sirolimus and Reperfusion-Injury

sirolimus has been researched along with Reperfusion-Injury* in 105 studies

Reviews

3 review(s) available for sirolimus and Reperfusion-Injury

ArticleYear
    The Egyptian journal of chest diseases and tuberculosis, 2016, Volume: 65, Issue:1

    Middle East Respiratory Syndrome (MERS) is a novel respiratory illness firstly reported in Saudi Arabia in 2012. It is caused by a new corona virus, called MERS corona virus (MERS-CoV). Most people who have MERS-CoV infection developed severe acute respiratory illness.. This work is done to determine the clinical characteristics and the outcome of intensive care unit (ICU) admitted patients with confirmed MERS-CoV infection.. This study included 32 laboratory confirmed MERS corona virus infected patients who were admitted into ICU. It included 20 (62.50%) males and 12 (37.50%) females. The mean age was 43.99 ± 13.03 years. Diagnosis was done by real-time reverse transcription polymerase chain reaction (rRT-PCR) test for corona virus on throat swab, sputum, tracheal aspirate, or bronchoalveolar lavage specimens. Clinical characteristics, co-morbidities and outcome were reported for all subjects.. Most MERS corona patients present with fever, cough, dyspnea, sore throat, runny nose and sputum. The presence of abdominal symptoms may indicate bad prognosis. Prolonged duration of symptoms before patients' hospitalization, prolonged duration of mechanical ventilation and hospital stay, bilateral radiological pulmonary infiltrates, and hypoxemic respiratory failure were found to be strong predictors of mortality in such patients. Also, old age, current smoking, smoking severity, presence of associated co-morbidities like obesity, diabetes mellitus, chronic heart diseases, COPD, malignancy, renal failure, renal transplantation and liver cirrhosis are associated with a poor outcome of ICU admitted MERS corona virus infected patients.. Plasma HO-1, ferritin, p21, and NQO1 were all elevated at baseline in CKD participants. Plasma HO-1 and urine NQO1 levels each inversely correlated with eGFR (. SnPP can be safely administered and, after its injection, the resulting changes in plasma HO-1, NQO1, ferritin, and p21 concentrations can provide information as to antioxidant gene responsiveness/reserves in subjects with and without kidney disease.. A Study with RBT-1, in Healthy Volunteers and Subjects with Stage 3-4 Chronic Kidney Disease, NCT0363002 and NCT03893799.. HFNC did not significantly modify work of breathing in healthy subjects. However, a significant reduction in the minute volume was achieved, capillary [Formula: see text] remaining constant, which suggests a reduction in dead-space ventilation with flows > 20 L/min. (ClinicalTrials.gov registration NCT02495675).. 3 组患者手术时间、术中显性失血量及术后 1 周血红蛋白下降量比较差异均无统计学意义(. 对于肥胖和超重的膝关节单间室骨关节炎患者,采用 UKA 术后可获满意短中期疗效,远期疗效尚需进一步随访观察。.. Decreased muscle strength was identified at both time points in patients with hEDS/HSD. The evolution of most muscle strength parameters over time did not significantly differ between groups. Future studies should focus on the effectiveness of different types of muscle training strategies in hEDS/HSD patients.. These findings support previous adverse findings of e-cigarette exposure on neurodevelopment in a mouse model and provide substantial evidence of persistent adverse behavioral and neuroimmunological consequences to adult offspring following maternal e-cigarette exposure during pregnancy. https://doi.org/10.1289/EHP6067.. This RCT directly compares a neoadjuvant chemotherapy regimen with a standard CROSS regimen in terms of overall survival for patients with locally advanced ESCC. The results of this RCT will provide an answer for the controversy regarding the survival benefits between the two treatment strategies.. NCT04138212, date of registration: October 24, 2019.. Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T. If milk is exposed to excessive amounts of light, Vitamins B. The two concentration of ZnO nanoparticles in the ambient air produced two different outcomes. The lower concentration resulted in significant increases in Zn content of the liver while the higher concentration significantly increased Zn in the lungs (p < 0.05). Additionally, at the lower concentration, Zn content was found to be lower in brain tissue (p < 0.05). Using TEM/EDX we detected ZnO nanoparticles inside the cells in the lungs, kidney and liver. Inhaling ZnO NP at the higher concentration increased the levels of mRNA of the following genes in the lungs: Mt2 (2.56 fold), Slc30a1 (1.52 fold) and Slc30a5 (2.34 fold). At the lower ZnO nanoparticle concentration, only Slc30a7 mRNA levels in the lungs were up (1.74 fold). Thus the two air concentrations of ZnO nanoparticles produced distinct effects on the expression of the Zn-homeostasis related genes.. Until adverse health effects of ZnO nanoparticles deposited in organs such as lungs are further investigated and/or ruled out, the exposure to ZnO nanoparticles in aerosols should be avoided or minimised.

    Topics: A549 Cells; Acetylmuramyl-Alanyl-Isoglutamine; Acinetobacter baumannii; Acute Lung Injury; Adaptor Proteins, Signal Transducing; Adenine; Adenocarcinoma; Adipogenesis; Administration, Cutaneous; Administration, Ophthalmic; Adolescent; Adsorption; Adult; Aeromonas hydrophila; Aerosols; Aged; Aged, 80 and over; Aging; Agriculture; Air Pollutants; Air Pollution; Airway Remodeling; Alanine Transaminase; Albuminuria; Aldehyde Dehydrogenase 1 Family; Algorithms; AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; Alzheimer Disease; Amino Acid Sequence; Ammonia; Ammonium Compounds; Anaerobiosis; Anesthetics, Dissociative; Anesthetics, Inhalation; Animals; Anti-Bacterial Agents; Anti-HIV Agents; Anti-Infective Agents; Anti-Inflammatory Agents; Antibiotics, Antineoplastic; Antibodies, Antineutrophil Cytoplasmic; Antibodies, Monoclonal, Humanized; Antifungal Agents; Antigens, Bacterial; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Antitubercular Agents; Antiviral Agents; Apolipoproteins E; Apoptosis; Arabidopsis; Arabidopsis Proteins; Arsenic; Arthritis, Rheumatoid; Asthma; Atherosclerosis; ATP-Dependent Proteases; Attitude of Health Personnel; Australia; Austria; Autophagy; Axitinib; Bacteria; Bacterial Outer Membrane Proteins; Bacterial Proteins; Bacterial Toxins; Bacterial Typing Techniques; Bariatric Surgery; Base Composition; Bayes Theorem; Benzoxazoles; Benzylamines; beta Catenin; Betacoronavirus; Betula; Binding Sites; Biological Availability; Biological Oxygen Demand Analysis; Biomarkers; Biomarkers, Tumor; Biopsy; Bioreactors; Biosensing Techniques; Birth Weight; Blindness; Blood Chemical Analysis; Blood Gas Analysis; Blood Glucose; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Blood-Brain Barrier; Blotting, Western; Body Mass Index; Body Weight; Bone and Bones; Bone Density; Bone Resorption; Borates; Brain; Brain Infarction; Brain Injuries, Traumatic; 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Transistors, Electronic; Translational Research, Biomedical; Transplantation Tolerance; Transplantation, Homologous; Transportation; Treatment Outcome; Tretinoin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Tubulin Modulators; Tumor Microenvironment; Tumor Necrosis Factor Inhibitors; Tumor Necrosis Factor-alpha; Twins; Ultrasonic Therapy; Ultrasonography; Ultraviolet Rays; United States; Up-Regulation; Uranium; Urethra; Urinary Bladder; Urodynamics; Uromodulin; Uveitis; Vasoconstrictor Agents; Ventricular Function, Left; Vero Cells; Vesicular Transport Proteins; Viral Nonstructural Proteins; Visual Acuity; Vital Capacity; Vitamin D; Vitamin D Deficiency; Vitamin K 2; Vitamins; Volatilization; Voriconazole; Waiting Lists; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; Whole Genome Sequencing; Wine; Wnt Signaling Pathway; Wound Healing; Wounds and Injuries; WW Domains; X-linked Nuclear Protein; X-Ray Diffraction; Xanthines; Xenograft Model Antitumor Assays; YAP-Signaling Proteins; Yogurt; Young Adult; Zebrafish; Zebrafish Proteins; Ziziphus

2016
Emerging functions of autophagy in kidney transplantation.
    American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons, 2014, Volume: 14, Issue:1

    In response to ischemic, toxic or immunological insults, the more frequent injuries encountered by the kidney, cells must adapt to maintain vital metabolic functions and avoid cell death. Among the adaptive responses activated, autophagy emerges as an important integrator of various extracellular and intracellular triggers (often related to nutrients availability or immunological stimuli), which, as a consequence,may regulate cell viability, and also immune functions,both innate or adaptive. The aim of this review is to make the synthesis of the recent literature on the implications of autophagy in the kidney transplantation field and to discuss the future directions for research.

    Topics: Adaptive Immunity; Autophagy; Cyclosporine; Humans; Immunity, Innate; Immunosuppressive Agents; Kidney; Kidney Transplantation; Reperfusion Injury; Sirolimus

2014
The multifunctional role of mTOR in innate immunity: implications for transplant immunity.
    American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons, 2009, Volume: 9, Issue:12

    The mammalian target of rapamycin (mTOR) is an evolutionary conserved serine-threonine kinase that senses various environmental stimuli in most cells primarily to control cell growth. Restriction of cellular proliferation by mTOR inhibition led to the use of mTOR inhibitors as immunosuppressants in allogeneic transplantation as well as novel anticancer agents. However, distinct inflammatory side effects such as fever, pneumonitis, glomerulonephritis or anemia of chronic disease have been observed under this treatment regime. Apart from the mere cell-cycle regulatory effect of mTOR in dividing cells, recent data revealed a master regulatory role of mTOR in the innate immune system. Hence, inhibition of mTOR promotes proinflammatory cytokines such as IL-12 and IL-1beta, inhibits the anti-inflammatory cytokine IL-10 and boosts MHC antigen presentation via autophagy in monocytes/macrophages and dendritic cells. Moreover, mTOR regulates type I interferon production and the expression of chemokine receptors and costimulatory molecules. These results place mTOR in a complex immunoregulatory context by controlling innate and adaptive immune responses. In this review, we discuss the clinical consequences of mTOR-inhibitor therapy and aim to integrate this recent data into our current view of the molecular mechanisms of clinically employed mTOR inhibitors and discuss their relevance with special emphasis to transplantation.

    Topics: Animals; Autophagy; Cell Cycle; Dendritic Cells; Humans; Immunity, Innate; Intercellular Adhesion Molecule-1; Intracellular Signaling Peptides and Proteins; Killer Cells, Natural; Lung Diseases, Interstitial; Macrophages; Mice; Protein Serine-Threonine Kinases; Rats; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2009

Trials

1 trial(s) available for sirolimus and Reperfusion-Injury

ArticleYear
    The Egyptian journal of chest diseases and tuberculosis, 2016, Volume: 65, Issue:1

    Middle East Respiratory Syndrome (MERS) is a novel respiratory illness firstly reported in Saudi Arabia in 2012. It is caused by a new corona virus, called MERS corona virus (MERS-CoV). Most people who have MERS-CoV infection developed severe acute respiratory illness.. This work is done to determine the clinical characteristics and the outcome of intensive care unit (ICU) admitted patients with confirmed MERS-CoV infection.. This study included 32 laboratory confirmed MERS corona virus infected patients who were admitted into ICU. It included 20 (62.50%) males and 12 (37.50%) females. The mean age was 43.99 ± 13.03 years. Diagnosis was done by real-time reverse transcription polymerase chain reaction (rRT-PCR) test for corona virus on throat swab, sputum, tracheal aspirate, or bronchoalveolar lavage specimens. Clinical characteristics, co-morbidities and outcome were reported for all subjects.. Most MERS corona patients present with fever, cough, dyspnea, sore throat, runny nose and sputum. The presence of abdominal symptoms may indicate bad prognosis. Prolonged duration of symptoms before patients' hospitalization, prolonged duration of mechanical ventilation and hospital stay, bilateral radiological pulmonary infiltrates, and hypoxemic respiratory failure were found to be strong predictors of mortality in such patients. Also, old age, current smoking, smoking severity, presence of associated co-morbidities like obesity, diabetes mellitus, chronic heart diseases, COPD, malignancy, renal failure, renal transplantation and liver cirrhosis are associated with a poor outcome of ICU admitted MERS corona virus infected patients.. Plasma HO-1, ferritin, p21, and NQO1 were all elevated at baseline in CKD participants. Plasma HO-1 and urine NQO1 levels each inversely correlated with eGFR (. SnPP can be safely administered and, after its injection, the resulting changes in plasma HO-1, NQO1, ferritin, and p21 concentrations can provide information as to antioxidant gene responsiveness/reserves in subjects with and without kidney disease.. A Study with RBT-1, in Healthy Volunteers and Subjects with Stage 3-4 Chronic Kidney Disease, NCT0363002 and NCT03893799.. HFNC did not significantly modify work of breathing in healthy subjects. However, a significant reduction in the minute volume was achieved, capillary [Formula: see text] remaining constant, which suggests a reduction in dead-space ventilation with flows > 20 L/min. (ClinicalTrials.gov registration NCT02495675).. 3 组患者手术时间、术中显性失血量及术后 1 周血红蛋白下降量比较差异均无统计学意义(. 对于肥胖和超重的膝关节单间室骨关节炎患者,采用 UKA 术后可获满意短中期疗效,远期疗效尚需进一步随访观察。.. Decreased muscle strength was identified at both time points in patients with hEDS/HSD. The evolution of most muscle strength parameters over time did not significantly differ between groups. Future studies should focus on the effectiveness of different types of muscle training strategies in hEDS/HSD patients.. These findings support previous adverse findings of e-cigarette exposure on neurodevelopment in a mouse model and provide substantial evidence of persistent adverse behavioral and neuroimmunological consequences to adult offspring following maternal e-cigarette exposure during pregnancy. https://doi.org/10.1289/EHP6067.. This RCT directly compares a neoadjuvant chemotherapy regimen with a standard CROSS regimen in terms of overall survival for patients with locally advanced ESCC. The results of this RCT will provide an answer for the controversy regarding the survival benefits between the two treatment strategies.. NCT04138212, date of registration: October 24, 2019.. Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T. If milk is exposed to excessive amounts of light, Vitamins B. The two concentration of ZnO nanoparticles in the ambient air produced two different outcomes. The lower concentration resulted in significant increases in Zn content of the liver while the higher concentration significantly increased Zn in the lungs (p < 0.05). Additionally, at the lower concentration, Zn content was found to be lower in brain tissue (p < 0.05). Using TEM/EDX we detected ZnO nanoparticles inside the cells in the lungs, kidney and liver. Inhaling ZnO NP at the higher concentration increased the levels of mRNA of the following genes in the lungs: Mt2 (2.56 fold), Slc30a1 (1.52 fold) and Slc30a5 (2.34 fold). At the lower ZnO nanoparticle concentration, only Slc30a7 mRNA levels in the lungs were up (1.74 fold). Thus the two air concentrations of ZnO nanoparticles produced distinct effects on the expression of the Zn-homeostasis related genes.. Until adverse health effects of ZnO nanoparticles deposited in organs such as lungs are further investigated and/or ruled out, the exposure to ZnO nanoparticles in aerosols should be avoided or minimised.

    Topics: A549 Cells; Acetylmuramyl-Alanyl-Isoglutamine; Acinetobacter baumannii; Acute Lung Injury; Adaptor Proteins, Signal Transducing; Adenine; Adenocarcinoma; Adipogenesis; Administration, Cutaneous; Administration, Ophthalmic; Adolescent; Adsorption; Adult; Aeromonas hydrophila; Aerosols; Aged; Aged, 80 and over; Aging; Agriculture; Air Pollutants; Air Pollution; Airway Remodeling; Alanine Transaminase; Albuminuria; Aldehyde Dehydrogenase 1 Family; Algorithms; AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; Alzheimer Disease; Amino Acid Sequence; Ammonia; Ammonium Compounds; Anaerobiosis; Anesthetics, Dissociative; Anesthetics, Inhalation; Animals; Anti-Bacterial Agents; Anti-HIV Agents; Anti-Infective Agents; Anti-Inflammatory Agents; Antibiotics, Antineoplastic; Antibodies, Antineutrophil Cytoplasmic; Antibodies, Monoclonal, Humanized; Antifungal Agents; Antigens, Bacterial; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Antitubercular Agents; Antiviral Agents; Apolipoproteins E; Apoptosis; Arabidopsis; Arabidopsis Proteins; Arsenic; Arthritis, Rheumatoid; Asthma; Atherosclerosis; ATP-Dependent Proteases; Attitude of Health Personnel; Australia; Austria; Autophagy; Axitinib; Bacteria; Bacterial Outer Membrane Proteins; Bacterial Proteins; Bacterial Toxins; Bacterial Typing Techniques; Bariatric Surgery; Base Composition; Bayes Theorem; Benzoxazoles; Benzylamines; beta Catenin; Betacoronavirus; Betula; Binding Sites; Biological Availability; Biological Oxygen Demand Analysis; Biomarkers; Biomarkers, Tumor; Biopsy; Bioreactors; Biosensing Techniques; Birth Weight; Blindness; Blood Chemical Analysis; Blood Gas Analysis; Blood Glucose; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Blood-Brain Barrier; Blotting, Western; Body Mass Index; Body Weight; Bone and Bones; Bone Density; Bone Resorption; Borates; Brain; Brain Infarction; Brain Injuries, Traumatic; Brain Neoplasms; Breakfast; Breast Milk Expression; Breast Neoplasms; Bronchi; Bronchoalveolar Lavage Fluid; Buffaloes; Cadherins; Calcification, Physiologic; Calcium Compounds; Calcium, Dietary; Cannula; Caprolactam; Carbon; Carbon Dioxide; Carboplatin; Carcinogenesis; Carcinoma, Ductal; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Carcinoma, Non-Small-Cell Lung; Carcinoma, Pancreatic Ductal; Carcinoma, Renal Cell; Cardiovascular Diseases; Carps; Carrageenan; Case-Control Studies; Catalysis; Catalytic Domain; Cattle; CD8-Positive T-Lymphocytes; Cell Adhesion; Cell Cycle Proteins; Cell Death; Cell Differentiation; Cell Line; Cell Line, Tumor; Cell Movement; Cell Nucleus; Cell Phone Use; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cells, Cultured; Cellulose; Chemical Phenomena; Chemoradiotherapy; Child; Child Development; Child, Preschool; China; Chitosan; Chlorocebus aethiops; Cholecalciferol; Chromatography, Liquid; Circadian Clocks; 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Proto-Oncogene Proteins c-ret; Proto-Oncogene Proteins p21(ras); Proton Pumps; Protons; Protoporphyrins; Pseudomonas aeruginosa; Pseudomonas fluorescens; Pulmonary Artery; Pulmonary Disease, Chronic Obstructive; Pulmonary Gas Exchange; Pulmonary Veins; Pyrazoles; Pyridines; Pyrimidines; Qualitative Research; Quinoxalines; Rabbits; Random Allocation; Rats; Rats, Sprague-Dawley; Rats, Wistar; Receptors, Histamine H3; Receptors, Immunologic; Receptors, Transferrin; Recombinant Proteins; Recurrence; Reference Values; Referral and Consultation; Regional Blood Flow; Registries; Regulon; Renal Insufficiency, Chronic; Reperfusion Injury; Repressor Proteins; Reproducibility of Results; Republic of Korea; Research Design; Resistance Training; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Insufficiency; Resuscitation; Retinal Dehydrogenase; Retreatment; Retrospective Studies; Reverse Transcriptase Inhibitors; Rhinitis, Allergic; Ribosomal Proteins; Ribosomes; Risk Assessment; Risk Factors; Ritonavir; Rivers; RNA Interference; RNA-Seq; RNA, Messenger; RNA, Ribosomal, 16S; RNA, Small Interfering; Rosuvastatin Calcium; Rural Population; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Salivary Ducts; Salivary Gland Neoplasms; San Francisco; SARS-CoV-2; Satiation; Satiety Response; Schools; Schools, Pharmacy; Seasons; Seawater; Selection, Genetic; Sequence Analysis, DNA; Serine-Threonine Kinase 3; Sewage; Sheep; Sheep, Domestic; Shock, Hemorrhagic; Signal Transduction; Silver; Silymarin; Single Photon Emission Computed Tomography Computed Tomography; Sirolimus; Sirtuin 1; Skin; Skin Neoplasms; Skin Physiological Phenomena; Sleep Initiation and Maintenance Disorders; Social Class; Social Participation; Social Support; Soil; Soil Microbiology; Solutions; Somatomedins; Soot; Specimen Handling; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis; Spinal Fractures; Spirometry; Staphylococcus aureus; STAT1 Transcription Factor; STAT3 Transcription Factor; Streptomyces coelicolor; Stress, Psychological; Stroke; Stroke Volume; Structure-Activity Relationship; Students, Medical; Students, Pharmacy; Substance Abuse Treatment Centers; Sulfur Dioxide; Surface Properties; Surface-Active Agents; Surveys and Questionnaires; Survival Analysis; Survival Rate; Survivin; Sweden; Swine; Swine, Miniature; Sympathetic Nervous System; T-Lymphocytes, Regulatory; Talaromyces; Tandem Mass Spectrometry; tau Proteins; Telemedicine; Telomerase; Telomere; Telomere Homeostasis; Temperature; Terminally Ill; Th1 Cells; Thiamethoxam; Thiazoles; Thiophenes; Thioredoxin Reductase 1; Thrombosis; Thulium; Thyroid Cancer, Papillary; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Time Factors; Titanium; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; TOR Serine-Threonine Kinases; Transcription Factor AP-1; Transcription Factors; Transcription, Genetic; Transcriptional Activation; Transcriptome; Transforming Growth Factor beta1; Transistors, Electronic; Translational Research, Biomedical; Transplantation Tolerance; Transplantation, Homologous; Transportation; Treatment Outcome; Tretinoin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Tubulin Modulators; Tumor Microenvironment; Tumor Necrosis Factor Inhibitors; Tumor Necrosis Factor-alpha; Twins; Ultrasonic Therapy; Ultrasonography; Ultraviolet Rays; United States; Up-Regulation; Uranium; Urethra; Urinary Bladder; Urodynamics; Uromodulin; Uveitis; Vasoconstrictor Agents; Ventricular Function, Left; Vero Cells; Vesicular Transport Proteins; Viral Nonstructural Proteins; Visual Acuity; Vital Capacity; Vitamin D; Vitamin D Deficiency; Vitamin K 2; Vitamins; Volatilization; Voriconazole; Waiting Lists; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; Whole Genome Sequencing; Wine; Wnt Signaling Pathway; Wound Healing; Wounds and Injuries; WW Domains; X-linked Nuclear Protein; X-Ray Diffraction; Xanthines; Xenograft Model Antitumor Assays; YAP-Signaling Proteins; Yogurt; Young Adult; Zebrafish; Zebrafish Proteins; Ziziphus

2016

Other Studies

102 other study(ies) available for sirolimus and Reperfusion-Injury

ArticleYear
Rapamycin ameliorates brain damage and maintains mitochondrial dynamic balance in diabetic rats subjected to middle cerebral artery occlusion.
    Metabolic brain disease, 2023, Volume: 38, Issue:2

    To investigate the effect of rapamycin on mitochondrial dynamic balance in diabetic rats subjected to cerebral ischemia-reperfusion injury. Male Sprague Dawley (SD) rats (n = 78) were treated with high fat diet combined with streptozotocin injection to construct diabetic model in rats. Transient middle cerebral artery occlusion (MCAO) of 2 hours was induced and the brains were harvested after 1 and 3 days of reperfusion. Rapamycin was injected intraperitoneally for 3 days prior to and immediately after operation, once a day. The neurological function was assessed, infarct volumes were measured and HE staining as well as immunohistochemistry were performed. The protein of hippocampus was extracted and Western blotting were performed to detect the levels of mTOR, mitochondrial dynamin related proteins (DRP1, p-DRP1, OPA1), SIRT3, and Nix/BNIP3L. Diabetic hyperglycemia worsened the neurological function performance (p < 0.01), enlarged infarct size (p < 0.01) and increased ischemic neuronal cell death (p < 0.01). The increased damage was associated with elevations of p-mTOR, p-S6, and p-DRP1; and suppressions of SIRT3 and Nix/BNIP3L. Rapamycin ameliorated diabetes-enhanced ischemic brain damage and reversed the biomarker alterations caused by diabetes. High glucose activated mTOR pathway and caused mitochondrial dynamics toward fission. The protective effect of rapamycin against diabetes-enhanced ischemic brain damage was associated with inhibiting mTOR pathway, redressing mitochondrial dynamic imbalance, and elevating SIRT3 and Nix/BNIP3L expression.

    Topics: Animals; Apoptosis Regulatory Proteins; Brain; Brain Injuries; Brain Ischemia; Diabetes Mellitus, Experimental; Infarction, Middle Cerebral Artery; Male; Mitochondrial Dynamics; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Sirtuin 3; TOR Serine-Threonine Kinases

2023
Rapamycin Does Not Act as a Dietary Restriction Mimetic in the Protection against Ischemia Reperfusion Injury.
    European surgical research. Europaische chirurgische Forschung. Recherches chirurgicales europeennes, 2023, Volume: 64, Issue:2

    Short-term fasting protects against renal ischemia reperfusion injury (IRI). mTOR signaling is downregulated and may be involved in its protective effect. Rapamycin is considered a possible mimetic as it inhibits the mTOR pathway. This study examines the effect of rapamycin on renal IRI.. Mice were divided into four groups: ad libitum (AL), fasted (F), AL treated with rapamycin (AL+R), and F treated with rapamycin (F+R). Rapamycin was administered intraperitoneally 24 h before bilateral renal IRI was induced. Survival was monitored for 7 days. Renal cell death, regeneration, and mTOR activity were determined 48 h after reperfusion. Oxidative stress resistance of human renal proximal tubular and human primary tubular epithelial cells after rapamycin treatment was determined.. All F and F+R mice survived the experiment. Although rapamycin substantially downregulated mTOR activity, survival in the AL+R group was similar to AL (10%). Renal regeneration was significantly reduced in AL+R but not in F+R. After IRI (48 h), pS6K/S6K ratio was lower in F, F+R, and AL+R groups compared to AL fed animals (p = 0.02). In vitro, rapamycin also significantly downregulated mTOR activity (p < 0.001) but did not protect against oxidative stress.. Rapamycin pretreatment does not protect against renal IRI. Thus, protection against renal IRI by fasting is not exclusively mediated through inhibition of mTOR activity but may involve preservation of regenerative mechanisms despite mTOR downregulation. Therefore, rapamycin cannot be used as a dietary mimetic to protect against renal IRI.

    Topics: Animals; Humans; Kidney; Mice; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2023
Ischemic postconditioning protects against acute kidney injury after limb ischemia reperfusion by regulating HMGB1 release and autophagy.
    Renal failure, 2023, Volume: 45, Issue:1

    Ischemic postconditioning (I-PostC) has a protective effect against acute kidney injury (AKI) induced by limb ischemia-reperfusion (LIR); however, the exact mechanism remains to be elucidated. Our study aims to investigate the potential involvement of high-mobility group box 1 protein (HMGB1) and autophagy in renoprotection generated by I-PostC. A rat model of LIR-induced AKI was established and rats were randomly assigned to five groups: (i) sham-operated control, (ii) I/R, (iii) I/R + I-PostC, (iv) I/R + I-PostC + rapamycin (autophagy activator), and (v) I/R + I-PostC + 3-methyladenine (autophagy inhibitor). Morphological changes in the kidneys were assessed by histology, and ultrastructural changes in renal tubular epithelial cells and glomerular podocytes were observed by transmission electron microscopy. The levels of kidney function parameters, serum inflammatory factors, and autophagy markers were detected. The results showed that the levels of HMGB1, Beclin1, LC3-II/LC3-I, and inflammatory cytokines (TNF-α and IL-6) were significantly higher in the I/R group compared to the sham control in serum and in renal tissues. I-PostC significantly reduced the levels of HMGB1, Beclin1, LC3-II/LC3-I, and inflammatory cytokines in renal tissues and improved renal function. Renal histopathology and ultrastructural observations indicated that I-PostC alleviated renal tissue injury. In addition, rapamycin (autophagy activator) treatment increased the levels of inflammatory cytokine expression levels and decreased renal function, reversed the protective effect of I-PostC against LIR-induced AKI. In conclusion, I-PostC could play a protective role against AKI by regulating the release of HMGB1 and inhibiting autophagy activation.

    Topics: Acute Kidney Injury; Animals; Autophagy; Beclin-1; Cytokines; HMGB1 Protein; Ischemia; Ischemic Postconditioning; Rats; Reperfusion; Reperfusion Injury; Sirolimus

2023
Electroacupuncture Pretreatment Alleviates Cerebral Ischemia-Reperfusion Injury by Regulating Mitophagy via mTOR-ULK1/FUNDC1 Axis in Rats.
    Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 2022, Volume: 31, Issue:1

    Electroacupuncture (EA) pretreatment has been shown to alleviate cerebral ischemia-reperfusion (I/R) injury; however, the underlying mechanism remains unclear. To investigate the involvement of mTOR signaling in the protective role of EA in I/R-induced brain damage and mitochondrial injury.. Sprague-Dawley male rats were pretreated with vehicle, EA (at Baihui and Shuigou acupoints), or rapamycin + EA for 30 min daily for 5 consecutive days, followed by the middle cerebral artery occlusion to induce I/R injury. The neurological functions of the rats were assessed using the Longa neurological deficit scores. The rats were sacrificed immediately after neurological function assessment. The brains were obtained for the measurements of cerebral infarct area. The mitochondrial structural alterations were observed under transmission electron microscopy. The mitochondrial membrane potential changes were detected by JC-1 staining. The alterations in autophagy-related protein expression were examined using Western blot analysis.. Compared with untreated I/R rats, EA-pretreated rats exhibited significantly decreased neurological deficit scores and cerebral infarct volumes. EA pretreatment also reversed I/R-induced mitochondrial structural abnormalities and loss of mitochondrial membrane potential. Furthermore, EA pretreatment downregulated the protein expression of LC3-II, p-ULK1, and FUNDC1 while upregulating the protein expression of p-mTORC1 and LC3-I. Rapamycin effectively blocked the above-mentioned effects of EA.. EA pretreatment at Baihui and Shuigou alleviates cerebral I/R injury and mitochondrial impairment in rats through activating the mTORC1 signaling. The suppression of autophagy-related p-ULK1/FUNDC1 pathway is involved in the neuroprotective effects of EA.

    Topics: Animals; Autophagy-Related Protein-1 Homolog; Brain Ischemia; Electroacupuncture; Infarction, Middle Cerebral Artery; Male; Mechanistic Target of Rapamycin Complex 1; Membrane Proteins; Mitochondrial Proteins; Mitophagy; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; TOR Serine-Threonine Kinases

2022
Regulation of the autophagy plays an important role in acute kidney injury induced acute lung injury.
    Renal failure, 2022, Volume: 44, Issue:1

    This study aimed to investigate the regulatory role of autophagy in acute kidney injury (AKI) induced acute lung injury (ALI).. The male Sprague-Dawley rats were divided into four groups: normal saline-treated sham rats (sham group), normal saline-treated ischemia-reperfusion injury rats (IRI group), 3-methyladenine-treated IRI rats (3-MA group), and rapamycin-treated IRI rats (RA group). The rats in the IRI rat model received the nephrectomy of the right kidney and was subjected to 60 mins of left renal pedicle occlusion, followed by 12, 24, 48, and 72 h of reperfusion. The levels of Scr, BUN, wet-to-dry ratio of lung, inflammatory cytokines, and oxidative stress were determined. The damage to tissues was detected by histological examinations. The western blot and immunohistochemistry methods were conducted to determine the expression of indicated proteins.. Renal IRI could induce the pulmonary injury after AKI, which caused significant increases in the function index of pulmonary and renal, the levels of inflammatory cytokines, and biomarkers of oxidative stress. In comparison to the IRI group, the RA group showed significantly decreased P62 and Caspase-3 expression and increased LC-II/LC3-I, Beclin-1, Bcl-2, and unc-51-like autophagy activating kinase 1 expression. Meanwhile, by suppressing the inflammation and oxidative stress, as well as inhibiting the pathological lesions in kidney and lung tissues, the autophagy could effectively ameliorate IRI-induced AKI and ALI.. Autophagy plays an important role in AKI-induced ALI, which could be used as a new target for AKI therapy and reduce the mortality caused by the complication.

    Topics: Acute Kidney Injury; Acute Lung Injury; Animals; Apoptosis; Autophagy; Beclin-1; Biomarkers; Caspase 3; Cytokines; Kidney; Male; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2022
Functionalized nanoparticles with monocyte membranes and rapamycin achieve synergistic chemoimmunotherapy for reperfusion-induced injury in ischemic stroke.
    Journal of nanobiotechnology, 2021, Oct-21, Volume: 19, Issue:1

    Ischemic stroke is an acute and severe neurological disease, and reperfusion is an effective way to reverse brain damage after stroke. However, reperfusion causes secondary tissue damage induced by inflammatory responses, called ischemia/reperfusion (I/R) injury. Current therapeutic strategies that control inflammation to treat I/R are less than satisfactory.. We report a kind of shield and sword nano-soldier functionalized nanoparticles (monocyte membranes-coated rapamycin nanoparticles, McM/RNPs) that can reduce inflammation and relieve I/R injury by blocking monocyte infiltration and inhibiting microglia proliferation. The fabricated McM/RNPs can actively target and bind to inflammatory endothelial cells, which inhibit the adhesion of monocytes to the endothelium, thus acting as a shield. Subsequently, McM/RNPs can penetrate the endothelium to reach the injury site, similar to a sword, and release the RAP drug to inhibit the proliferation of inflammatory cells. In a rat I/R injury model, McM/RNPs exhibited improved active homing to I/R injury areas and greatly ameliorated neuroscores and infarct volume. Importantly, in vivo animal studies revealed good safety for McM/RNPs treatment.. The results demonstrated that the developed McM/RNPs may serve as an effective and safe nanovehicles for I/R injury therapy.

    Topics: Animals; Anti-Inflammatory Agents; Cell Membrane; Ischemic Stroke; Male; Monocytes; Nanoparticle Drug Delivery System; Nanoparticles; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2021
Influence of an Early Application of Mammalian Target of Rapamycin Inhibitors Everolimus and Sirolimus on Acute Vascular Inflammatory Responses After Ischemia-Reperfusion Injury.
    Experimental and clinical transplantation : official journal of the Middle East Society for Organ Transplantation, 2021, Volume: 19, Issue:1

    Ischemia-reperfusion injury is correlated with a substantial inflammatory response. Inflammation triggers the migration of cells through vessel endothelium and leads to serious tissue injury. Our hypothesis was that an early application of mammalian target of rapamycin inhibitors has an impact on human vessels after ischemia-reperfusion injury.. After exposure to ischemia for 5 hours, human vessels (veins and arteries) from 20 patients were reperfused for 120 minutes in an in vitro bioreactor with heparinized human blood after oxygenation and warming to 37 °C. The vessels were treated with mammalian target of rapamycin inhibitor everolimus (5 ng/mL, n = 7) or sirolimus (10 ng/mL, n = 6). As a control group, untreated human vessels were reperfused (n = 7). During the reperfusion period, blood samples were collected continuously (after 0, 15, 30, 60, 120 minutes); vessel biopsies were performed at the end. Oxygen consumption was measured during reperfusion to determine vessel viability. Inflammatory markers (interleukin 6, tumor necrosis factor α, vascular endothelial growth factor) were analyzed in blood samples. To quantify vascular inflammation, we investigated the expression of CD11 and CD31.. Physiological oxygen consumption and pH values verified vessel viability. After reperfusion, interleukin 6 and vascular endothelial growth factor levels were significantly increased in the control group over time, whereas everolimus and sirolimus showed no significant differences. Furthermore, tumor necrosis factor α level increased significantly in the sirolimus group, whereas the everolimus and control groups showed constant values. A significant decrease of expression of CD11b and CD31 in both mammalian target of rapamycin inhibitor cohorts compared with control cohort was investigated.. Early use of mammalian target of rapamycin inhibitors may limit an inflammatory rise of interleukin 6 and vascular endothelial growth factor after ischemia-reperfusion injury and could be associated with a restriction in vascular cell transmigration.

    Topics: Everolimus; Humans; In Vitro Techniques; Inflammation; Interleukin-6; Reperfusion Injury; Sirolimus; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A

2021
PTEN protects kidney against acute kidney injury by alleviating apoptosis and promoting autophagy via regulating HIF1-α and mTOR through PI3K/Akt pathway.
    Experimental cell research, 2021, 09-01, Volume: 406, Issue:1

    Phosphatase and tensin homolog (PTEN) deleted on human chromosome 10 is a tumor suppressor with bispecific phosphatase activity, which is often involved in the study of energy metabolism and tumorigenesis. PTEN is recently reported to participate in the process of acute injury. However, the mechanism of PTEN in Ischemia-Reperfusion Injury (IRI) has not yet been clearly elucidated. In this study, mice with bilateral renal artery ischemia-reperfusion and HK-2 cells with hypoxia/reoxygenation (H/R) were used as acute kidney injury models. We demonstrated that PTEN was downregulated in IRI-induced kidney as well as in H/R-induced HK-2 cells. By silencing and overexpressing PTEN with si-PTEN RNA and PHBLV-CMV-PTEN-flag lentivirus before H/R, we found that PTEN protected HK-2 cells against H/R-induced injury reflected by the change in cell activity and the release of LDH. Furthermore, we inhibited HIF1-α with PX-478 and inactivated mTOR with Rapamycin before the silence of PTEN in H/R model. Our data indicated that the renoprotective effect of PTEN worked via PI3K/Akt/mTOR pathway and PI3K/Akt/HIF1-α pathway, hence alleviating apoptosis and improving autophagy respectively. Our findings provide valuable insights into the molecular mechanism underlying renoprotection of PTEN on autophagy and apoptosis induced by renal IRI, which offers a novel therapeutic target for the treatment of AKI.

    Topics: Acute Kidney Injury; Animals; Apoptosis; Autophagy; bcl-2-Associated X Protein; Cell Line; Disease Models, Animal; Epithelial Cells; Gene Expression Regulation; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Kidney; Male; Mice; Mice, Inbred C57BL; Mustard Compounds; Phenylpropionates; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; PTEN Phosphohydrolase; Reperfusion Injury; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2021
Computational research of mTORC1 inhibitor on cerebral ischemia-reperfusion injury.
    Aging, 2021, 08-03, Volume: 13, Issue:15

    Ischemic stroke contributes to more than 80% of all strokes and has the four characteristics of high prevalence, high disability, high mortality, and high recurrence. Stroke is a preventable and controllable disease. In addition to controlling the primary disease, effective prevention and control measures need to be given to the occurrence and development of stroke. With the development and progress of modern treatment methods for ischemic stroke, the mortality and disability rate have decreased significantly. At present, the main treatment methods for ischemic stroke include thrombolysis, thrombus removal at the ultra-early stage, and treatment of improving collateral circulation in the acute phase. However, the ultra-early and early blood reperfusion involves reperfusion injury, which will cause secondary nerve damage, which is called cerebral ischemia/reperfusion injury (CIRI). Studies have found that autophagy is involved in the entire process of CIRI and can reduce the damage of CIRI. The mammalian target of Rapamycin (mTORC1) is the primary signal pathway regulating autophagy. And the mTORC1 inhibitor, Rapamycin, has been proved to exert neuroprotective effects in the ultra-early and early cerebral ischemia-reperfusion. Therefore, screening and designing mTORC1 inhibitors is very important to control reperfusion injury and reduce neuronal death and apoptosis. In this research, plenty of computer-assisted was applied to virtually screen and select potential mTORC1's inhibitors. We used Libdock to screen the structure and performed toxicity predictions, ADME (absorption, distribution, metabolism, excretion) to predict small molecules' pharmacological and toxicological properties. To assess the binding mechanism and affinity between the mTORC1 dimer and the ligand, molecular docking was performed. Then, the pharmacophore of small molecules in the docking conformation with the protein was supplemented by Schrodinger. Additionally, molecular dynamics simulations were conducted to assess if the ligand-receptor complex was stable in a natural environment. Furthermore, an experiment was performed to verify the inhibitory effect of compound 1 and compound 2 on mTOR protein. All in all, the study provides a hand of candidate drugs as well as pharmacological properties, which can play an essential role in mTORC1 inhibitors.

    Topics: Animals; Apoptosis; Autophagy; Female; Humans; Ischemic Stroke; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Molecular Docking Simulation; Neurons; Neuroprotective Agents; Rats; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2021
Low-dose rapamycin does not impair vascular integrity and tubular regeneration after kidney transplantation in rats.
    Scientific reports, 2021, 08-11, Volume: 11, Issue:1

    mTOR inhibitors offer advantages after kidney transplantation including antiviral and antitumor activity besides facilitating low calcineurin inhibitor exposure to reduce nephrotoxicity. Concerns about adverse effects due to antiproliferative and antiangiogenic properties have limited their clinical use particularly early after transplantation. Interference with vascular endothelial growth factor (VEGF)-A, important for physiologic functioning of renal endothelial cells and tubular epithelium, has been implicated in detrimental renal effects of mTOR inhibitors. Low doses of Rapamycin (loading dose 3 mg/kg bodyweight, daily doses 1.5 mg/kg bodyweight) were administered in an allogenic rat kidney transplantation model resulting in a mean through concentration of 4.30 ng/mL. Glomerular and peritubular capillaries, tubular cell proliferation, or functional recovery from preservation/reperfusion injury were not compromised in comparison to vehicle treated animals. VEGF-A, VEGF receptor 2, and the co-receptor Neuropilin-1 were upregulated by Rapamycin within 7 days. Rat proximal tubular cells (RPTC) responded in vitro to hypoxia with increased VEGF-A and VEGF-R1 expression that was not suppressed by Rapamycin at therapeutic concentrations. Rapamycin did not impair proliferation of RPTC under hypoxic conditions. Low-dose Rapamycin early posttransplant does not negatively influence the VEGF network crucial for recovery from preservation/reperfusion injury. Enhancement of VEGF signaling peritransplant holds potential to further improve outcomes.

    Topics: Animals; Cell Proliferation; Dose-Response Relationship, Drug; Gene Expression; Kidney Transplantation; Kidney Tubules, Proximal; Male; Negative Results; Rats, Inbred F344; Rats, Inbred Lew; Regeneration; Reperfusion Injury; Sirolimus; Vascular Endothelial Growth Factor A

2021
Dexmedetomidine Protects Against Oxygen-Glucose Deprivation-Induced Injury Through Inducing Astrocytes Autophagy via TSC2/mTOR Pathway.
    Neuromolecular medicine, 2020, Volume: 22, Issue:2

    Although there is an increment in stroke burden in the world, stroke therapeutic strategies are still extremely limited to a minority of patients. We previously demonstrated that dexmedetomidine (DEX) protects against focal cerebral ischemia via inhibiting neurons autophagy. Nevertheless, the role of DEX in regulating astrocytes autophagic status in oxygen-glucose deprivation, a condition that mimics cerebral ischemia, is still unknown. In this study, we have shown that DEX and DEX + RAPA (autophagy inducer) increased viability and reduced apoptosis of primary astrocytes in oxygen-glucose deprivation (OGD) model compared with DEX + 3-methyladenine (3-MA) (autophagy inhibitor). DEX induced the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin 1, while reduced the expression of p62 in primary cultured astrocytes through induction of autophagy. In addition, DEX enhanced the expression of tuberous sclerosis complex 2 (TSC2) in primary cultured astrocytes, while reduced the expression of mammalian target of rapamycin (mTOR). In conclusion, our study suggests that DEX exerts a neuroprotection against OGD-induced astrocytes injury via activation of astrocytes autophagy by regulating the TSC2/mTOR signaling pathway, which provides a new insight into the mechanisms of DEX treatment for acute ischemic injury.

    Topics: Adenine; Animals; Astrocytes; Autophagy; Cell Hypoxia; Cells, Cultured; Dexmedetomidine; Drug Evaluation, Preclinical; Glucose; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Neuroprotective Agents; Random Allocation; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein

2020
Autophagy decreases alveolar epithelial cell injury by regulating the release of inflammatory mediators.
    Journal of cellular physiology, 2020, Volume: 235, Issue:11

    To research the impact of autophagy on alveolar epithelial cell inflammation and its possible mechanism in the early stages of hypoxia, we established a cell hypoxia-reoxygenation model and orthotopic left lung ischemia-reperfusion model. Rat alveolar epithelial cells stably expressing GFP-LC3 were treated with an autophagy inhibitor (3-MA) or an autophagy promoter (rapamycin), followed by hypoxia-reoxygenation treatment for 2, 4, and 6 hr in vitro. In vivo, 20 male Sprague Dawley rats were randomly divided into four groups (model group: No blocking of the hilum in the left lung; control group: Blocking of the hilum in the left lung for 1 hr with dimethyl sulfoxide lavage; 3-MA group: Blocking of the hilum in the left lung for 1 hr with 100 ml/kg of 3-MA (5 μmol/L) solution lavage; and rapamycin group: Blocking of the hilum in the left lung for 1 hr with 100 ml/kg of rapamycin (250 nmol/L) solution lavage) to establish an orthotopic left lung ischemia model. This study demonstrated that rapamycin significantly suppressed the nuclear factor kappa B signaling pathway and limited the expression of proinflammatory factors. A contrary result was found after the 3-MA pretreatment. These findings indicate that autophagy reduces ischemia-reperfusion injury by repressing inflammatory signaling pathways in the early stages of hypoxia in vitro and in vivo. Autophagy could be a new protective method for application in lung ischemia-reperfusion injury.

    Topics: Alveolar Epithelial Cells; Animals; Autophagy; Cell Hypoxia; Dimethyl Sulfoxide; Disease Models, Animal; Endoplasmic Reticulum Stress; Humans; Inflammation; Inflammation Mediators; Lung; Lung Injury; Male; Microtubule-Associated Proteins; NF-kappa B; Rats; Reperfusion Injury; Signal Transduction; Sirolimus

2020
Prevention of renal ischemia and reperfusion injury by penehyclidine hydrochloride through autophagy activation.
    Molecular medicine reports, 2020, Volume: 21, Issue:5

    Penehyclidine hydrochloride (PHC) suppresses renal ischemia and reperfusion (I/R) injury (IRI); however, the underlying mechanism of action that achieves this function remains largely unknown. The present study aimed to investigate the potential role of autophagy in PHC‑induced suppression of renal IRI, as well as the involvement of cell proliferation and apoptosis. A rat IRI model and a cellular hypoxia/oxygenation (H/R) model were established; PHC, 3‑methyladenine (3‑MA) and rapamycin (Rapa) were administered to the IRI model rats prior to I/R induction and to H/R cells following reperfusion. Serum creatinine was measured using a biochemistry analyzer, whereas aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) expression levels were detected using ELISA kits. Renal tissue injury was evaluated by histological examination. In addition, microtubule‑associated protein light chain 3B (LC3B) expression, autophagosome formation, cell proliferation and apoptosis were detected in the cellular H/R model. The results demonstrated that I/R induced renal injury in IRI model rats, upregulated serum creatinine, ALAT and ASAT expression levels, and increased autophagic processes. In contrast, pretreatment with PHC or Rapa significantly prevented these I/R‑induced changes, whereas the administration of 3‑MA enhanced I/R‑induced injuries through suppressing autophagy. PHC and Rapa increased LC3B and Beclin‑1 expression levels, but decreased sequestome 1 (p62) expression in the cellular H/R model, whereas 3‑MA prevented these PHC‑induced changes. PHC and Rapa promoted proliferation and autophagy in the cellular H/R model; these effects were accompanied by increased expression levels of LC3B and Beclin‑1, and reduced p62 expression levels, whereas these levels were inhibited by 3‑MA. Furthermore, PHC and Rapa inhibited apoptosis in the cellular H/R model through increasing Bcl‑2 expression levels, and suppressing Bax and caspase‑3 expression levels; the opposite effect was induced by 3‑MA. In conclusion, PHC suppressed renal IRI through the induction of autophagy, which in turn promoted proliferation and suppressed apoptosis in renal cells.

    Topics: Adenine; Alanine Transaminase; Animals; Apoptosis; Aspartate Aminotransferases; Autophagy; Beclin-1; Caspase 3; Cell Proliferation; Disease Models, Animal; Ischemia; Kidney; Male; Quinuclidines; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2020
Aescin Protects Neuron from Ischemia-Reperfusion Injury via Regulating the PRAS40/mTOR Signaling Pathway.
    Oxidative medicine and cellular longevity, 2020, Volume: 2020

    Topics: Animals; Cell Hypoxia; Cell Survival; Cells, Cultured; Escin; Female; Glucose; L-Lactate Dehydrogenase; Mice; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Phosphoproteins; Phosphorylation; Reperfusion Injury; RNA Interference; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2020
Galuteolin Inhibited Autophagy for Neuroprotection Against Transient Focal Cerebral Ischemia in Rats.
    Neuromolecular medicine, 2020, Volume: 22, Issue:4

    Galuteolin, a Chinese herbal medicine, purified from Lonicera Japonica. In this study, we aimed to investigate the neuroprotective effect of galuteolin against cerebral ischemia/reperfusion (I/R) injury. We administered galuteolin or galuteolin and rapamycin to rats which had middle cerebral artery occlusion/reperfusion (MCAO/R). A series of characterizations were carried out to monitor the outcomes of galuteolin in I/R rats regarding the infarct volumes, neurological deficits, and brain water, as well as its effect on neuroprotection and autophagy. It was found that galuteolin significantly reduced the infarct volume, brain water content, and the neurological deficits in a dose-dependent manner. Neuron damages were decreased in the hippocampal carotid artery 1 pyramidal layer by galuteolin. The expression levels of neuron-specific enolase (NSE) increased after galuteolin treatment. Galuteolin significantly decreased the expression levels of autophagy-related proteins. In addition, galuteolin decreased rapamycin-related neuron damages and activations of autophagy in I/R rats. Our data suggested that galuteolin can inhibit ischemic brain injuries through the regulation of autophagy-related indicators in I/R.

    Topics: Animals; Autophagy; Body Water; Cerebral Infarction; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Glucosides; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Luteolin; Male; Molecular Structure; Neurons; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2020
Modulation of oxidative-nitrosative stress and inflammatory response by rapamycin in target and distant organs in rats exposed to hindlimb ischemia-reperfusion: the role of mammalian target of rapamycin.
    Canadian journal of physiology and pharmacology, 2019, Volume: 97, Issue:12

    Topics: Animals; Biomarkers; Gene Expression Regulation, Enzymologic; Hindlimb; Inflammation; Kidney; Male; Muscle, Skeletal; NF-KappaB Inhibitor alpha; Nitrosative Stress; Oxidative Stress; Rats; Rats, Wistar; Reperfusion Injury; Ribosomal Protein S6; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factor RelA

2019
Angiopoietin-1 Protects Spinal Cord Ischemia and Reperfusion Injury by Inhibiting Autophagy in Rats.
    Neurochemical research, 2019, Volume: 44, Issue:12

    Spinal cord ischemia and reperfusion (SCIR) injury can induce autophagy, which is involved in the survival of neurons. However, whether autophagy plays a neuroprotective or a detrimental role in SCIR injury remains controversial. Angiopoietin-1 (Ang-1), an endothelial growth factor, has been shown to have neuroprotective effects. The present study aimed to explore the neuroprotective mechanisms of Ang-1 in neuronal cells in a rat model of SCIR injury in vivo. Ang-1 protein and rapamycin were injected intrathecally. Basso Beattie Bresnahan (BBB) scoring and hematoxylin and eosin staining were used to assess the degree of SCIR injury. Proteins that reflected the level of autophagy expression, such as Beclin-1 and LC3, were evaluated by western blotting. The results indicated that SCIR injury resulted in loss in lower limb motor function. Ang-1 protein inhibited the expression of Beclin-1 and LC3, which improved the BBB score and alleviated spinal cord injury. In contrast, rapamycin, an autophagy activator, caused the opposite effect. This study provides evidence that Ang-1 plays a neuroprotective role by inhibiting of autophagy expression in SCIR injury. Overall, findings could be useful for the treatment of SCIR injury.

    Topics: Angiopoietin-1; Animals; Autophagy; Male; Neurons; Neuroprotective Agents; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Spinal Cord; Spinal Cord Injuries; Spinal Cord Ischemia

2019
Rapamycin-inspired macrocycles with new target specificity.
    Nature chemistry, 2019, Volume: 11, Issue:3

    Rapamycin and FK506 are macrocyclic natural products with an extraordinary mode of action, in which they form binary complexes with FK506-binding protein (FKBP) through a shared FKBP-binding domain before forming ternary complexes with their respective targets, mechanistic target of rapamycin (mTOR) and calcineurin, respectively. Inspired by this, we sought to build a rapamycin-like macromolecule library to target new cellular proteins by replacing the effector domain of rapamycin with a combinatorial library of oligopeptides. We developed a robust macrocyclization method using ring-closing metathesis and synthesized a 45,000-compound library of hybrid macrocycles (named rapafucins) using optimized FKBP-binding domains. Screening of the rapafucin library in human cells led to the discovery of rapadocin, an inhibitor of nucleoside uptake. Rapadocin is a potent, isoform-specific and FKBP-dependent inhibitor of the equilibrative nucleoside transporter 1 and is efficacious in an animal model of kidney ischaemia reperfusion injury. Together, these results demonstrate that rapafucins are a new class of chemical probes and drug leads that can expand the repertoire of protein targets well beyond mTOR and calcineurin.

    Topics: Acute Kidney Injury; Animals; Cell Line; Drug Discovery; Human Umbilical Vein Endothelial Cells; Humans; Macrolides; Mice; Protective Agents; Proteome; Reperfusion Injury; Sirolimus; Swine; Tacrolimus; Tacrolimus Binding Proteins; TOR Serine-Threonine Kinases

2019
Preconditioning of umbilical cord-derived mesenchymal stem cells by rapamycin increases cell migration and ameliorates liver ischaemia/reperfusion injury in mice via the CXCR4/CXCL12 axis.
    Cell proliferation, 2019, Volume: 52, Issue:2

    Transfusion of umbilical cord-derived mesenchymal stem cells (UC-MSCs) is a novel strategy for treatment of various liver diseases. However, the therapeutic effect of UC-MSCs is limited because only a few UC-MSCs migrate towards the damaged regions. In this study, we observed the effects of autophagy on the migration of UC-MSCs in vitro and in a model of liver ischaemia/reperfusion (I/R) injury.. We investigated the effects of autophagy on the status of the cell, release of anti-inflammatory factors and migration of UC-MSCs in vitro. The therapeutic effects and in vivo migration of rapamycin-preconditioned UC-MSCs were observed in a C57/B6 mouse model of liver I/R injury.. Induction of autophagy by rapamycin enhanced the ability of UC-MSCs to migrate and release anti-inflammatory cytokines as well as increased expression of CXCR4 without affecting cell viability. Inhibition of CXCR4 activation markedly decreased migration of these cells. In a mouse model of liver I/R injury, we found significantly upregulated expression of CXCR12 in the damaged liver. More rapamycin-preconditioned UC-MSCs migrated towards the ischaemic regions than 3-methyladenine-preconditioned or non-preconditioned UC-MSCs, leading to improvement in hepatic performance, pathological changes and levels of inflammatory cytokines. These effects were abolished by AMD3100.. Preconditioning of UC-MSCs by rapamycin afforded increased protection against liver I/R injury by enhancing immunosuppression and strengthening the homing and migratory capacity of these cells via the CXCR4/CXCL12 axis.

    Topics: Animals; Cell Movement; Cells, Cultured; Chemokine CXCL12; Humans; Immunosuppressive Agents; Ischemic Preconditioning; Liver; Liver Diseases; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Receptors, CXCR4; Reperfusion Injury; Signal Transduction; Sirolimus; Umbilical Cord

2019
Aged kidneys are refractory to autophagy activation in a rat model of renal ischemia-reperfusion injury.
    Clinical interventions in aging, 2019, Volume: 14

    Ischemia-reperfusion (I/R) injury is the most common cause of acute kidney injury (AKI). Numerous therapeutic approaches for I/R injury have been studied, including autophagy, particularly in animal models of renal I/R injury derived from young or adult animals. However, the precise role of autophagy in renal ischemia-reperfusion in the aged animal model remains unclear. The purpose of this study was to demonstrate whether autophagy has similar effects on renal I/R injury in young and aged rats.. All rats were divided into two age groups (3 months and 24 months) with each group being further divided into four subgroups (sham, I/R, I/R+Rap (rapamycin, an activator of autophagy), I/R+3-MA (3-methyladenine, an inhibitor of autophagy)). The I/R+Rap and I/R+3-MA groups were intraperitoneally injected with rapamycin and 3-MA prior to ischemia. We then measured serum levels of urea nitrogen, creatinine and assessed damage in the renal tissue. Immunohistochemistry was used to assess LC3-II and caspase-3, and Western blotting was used to evaluate the autophagy-related proteins LC3-II, Beclin-1 and P62. Apoptosis and autophagosomes were evaluated by TUNEL and transmission electron microscopy, respectively.. Autophagy was activated in both young and aged rats by I/R and enhanced by rapamycin, although the level of autophagy was lower in the aged groups. In young rats, the activation of autophagy markedly improved renal function, reduced apoptosis in the renal tubular epithelial cells and the injury score in the renal tissue, thereby exerting protective effects on renal I/R injury. However, this level of protection was not present in aged rats.. Our data indicated that the activation of autophagy was ineffective in aged rat kidneys. These discoveries may have major implications in that severe apoptosis in aged kidneys might be refractory to antiapoptotic effect induced by the activation of autophagy.

    Topics: Acute Kidney Injury; Adenine; Age Factors; Animals; Apoptosis; Autophagosomes; Autophagy; Beclin-1; Blood Urea Nitrogen; Caspase 3; Creatinine; Disease Models, Animal; Kidney; Male; Microtubule-Associated Proteins; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2019
Inhibition of mitochondrial autophagy protects donor lungs for lung transplantation against ischaemia-reperfusion injury in rats via the mTOR pathway.
    Journal of cellular and molecular medicine, 2019, Volume: 23, Issue:5

    Impaired mitochondrial function is a key factor attributing to lung ischaemia-reperfusion (IR) injury, which contributes to major post-transplant complications. Thus, the current study was performed to investigate the role of mitochondrial autophagy in lung I/R injury and the involvement of the mTOR pathway. We established rat models of orthotopic left lung transplantation to investigate the role of mitochondrial autophagy in I/R injury following lung transplantation. Next, we treated the donor lungs with 3-MA and Rapamycin to evaluate mitochondrial autophagy, lung function and cell apoptosis with different time intervals of cold ischaemia preservation and reperfusion. In addition, mitochondrial autophagy, and cell proliferation and apoptosis of pulmonary microvascular endothelial cells (PMVECs) exposed to hypoxia-reoxygenation (H/R) were monitored after 3-MA administration or Rapamycin treatment. The cell apoptosis could be inhibited by mitochondrial autophagy at the beginning of lung ischaemia, but was rendered out of control when mitochondrial autophagy reached normal levels. After I/R of donor lung, the mitochondrial autophagy was increased until 6 hours after reperfusion and then gradually decreased. The elevation of mitochondrial autophagy was accompanied by promoted apoptosis, aggravated lung injury and deteriorated lung function. Moreover, the suppression of mitochondrial autophagy by 3-MA inhibited cell apoptosis of donor lung to alleviate I/R-induced lung injury as well as inhibited H/R-induced PMVEC apoptosis, and enhanced its proliferation. Finally, mTOR pathway participated in I/R- and H/R-mediated mitochondrial autophagy in regulation of cell apoptosis. Inhibition of I/R-induced mitochondrial autophagy alleviated lung injury via the mTOR pathway, suggesting a potential therapeutic strategy for lung I/R injury.

    Topics: Adenine; Animals; Autophagy; Endothelial Cells; Humans; Lung; Lung Transplantation; Mitochondria; Rats; Reperfusion Injury; Signal Transduction; Sirolimus; Tissue Donors; TOR Serine-Threonine Kinases

2019
Phosphorylated mTORC1 represses autophagic-related mRNA translation in neurons exposed to ischemia-reperfusion injury.
    Journal of cellular biochemistry, 2019, Volume: 120, Issue:9

    The sequential reactivation of mechanistic target of rapamycin (mTOR) inhibited autophagic flux in neurons exposed to oxygen-glucose deprivation/reperfusion (OGD/R), which was characterized by reduction of autophagosome formation and restriction of autolysosome degradation. However, its detailed molecular mechanism was still unknown. In this study, we further explore the existing form of mTOR and its suppression on the transcriptional levels of related mRNA from neurons exposed to ischemia-reperfusion injury.. The OGD/R or middle cerebral artery occlusion/reperfusion (MCAO/R)-treated neurons was used to simulate ischemia/reperfusion injury . Autophagy flux was monitored by means of microtubule-associated protein 1 light chain 3 (LC3) and p62. The reactivation of mTOR was determined by phosphorylation of ribosomal protein S6 kinase 1 (S6K1). Then the inhibitors of mTOR were used to confirm its existence form. Finally, the mRNA transcription levels were analyzed to observe the negative regulation of mTOR.. The sequential phosphorylation of mTOR contributed to the neuronal autophagy flux blocking. mTOR was re-phosphorylated and existed as mTOR complex 1 (mTORC1), which was supported by phosphorylation of S6K1 at Thr 389 in neurons. In addition, the phosphorylation of S6K1 was decreased roughly by applying mTORC1 inhibitors, rapamycin and torin 1. However, the administration of mTORC1/2 inhibitor PP242 could recover the phosphorylation of S6K1, which suggested that mTORC2 was involved in the regulation of mTORC1 activity. In paralleling with reactivation of mTORC1, related mRNA transcription was repressed in neurons under ischemia-reperfusion exposure in vivo and in vitro. The mRNA expression levels of LC3, Stx17, Vamp8, Snap29, Lamp2a, and Lamp2b were decreased in neurons after reperfusion, comparing with ischemia-treated neurons.. The reactivated mTORC1 could suppress the transcription levels of related mRNA, such as LC3, Stx17, Vamp8, Snap29, Lamp2a, and Lamp2b. The research will expand the horizons that mTOR would negatively regulate autophagy at transcription and post-translation levels in neurons suffering ischemia-reperfusion injury.

    Topics: Animals; Autophagy; Autophagy-Related Proteins; Cells, Cultured; Disease Models, Animal; Feedback, Physiological; Gene Expression Regulation; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Neurons; Phosphorylation; Reperfusion Injury; Ribosomal Protein S6 Kinases, 90-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2019
Inhibition of Autophagy Attenuated Intestinal Injury After Intestinal I/R via mTOR Signaling.
    The Journal of surgical research, 2019, Volume: 243

    Intestinal ischemia/reperfusion (I/R) is a grave condition related to high morbidity and mortality. Autophagy, which can induce a new cell death named type II programmed cell death, has been reported in some intestinal diseases, but little is known in I/R-induced intestinal injury. In this study, we aimed to explore the role of autophagy in intestinal injury induced by I/R and its potential mechanisms.. The rats pretreated with rapamycin or 3-methyladenine had intestinal I/R injury. After reperfusion, intestinal injury was measured by Chiu's score, intestinal mucosal wet-to-dry ratio, and lactic acid level. Intestinal mucosal oxidative stress level was measured by malondialdehyde and superoxide dismutase. Autophagosome, LC3, and p62 were detected to evaluate autophagy level. Mammalian target of rapamycin (mTOR) was detected to explore potential mechanism.. Chiu's score, intestinal mucosal wet-to-dry ratio, lactic acid level, malondialdehyde level, autophagosomes, and LC3-II/LC3-I were significantly increased, and superoxide dismutase level and expression of p62 were significantly decreased in intestinal mucosa after intestinal ischemia/reperfusion. Pretreatment with rapamycin significantly aggravated intestinal injury evidenced by increased Chiu's score, intestinal mucosal wet-to-dry ratio and lactic acid level, increased autophagy level evidenced by increased autophagosomes and LC3-II/LC3-I and decreased expression of p62, and downregulated expression of p-mTOR/mTOR. On the contrary, pretreatment with 3-methyladenine significantly attenuated intestinal injury and autophagy level and upregulated expression of p-mTOR/mTOR.. In summary, autophagy was significantly enhanced in intestinal mucosa after intestinal ischemia/reperfusion, and inhibition of autophagy attenuated intestinal injury induced by I/R through activating mTOR signaling.

    Topics: Adenine; Animals; Autophagy; Drug Evaluation, Preclinical; Intestinal Diseases; Intestinal Mucosa; Male; Malondialdehyde; Random Allocation; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Superoxide Dismutase; TOR Serine-Threonine Kinases

2019
Combined ischemic and rapamycin preconditioning alleviated liver ischemia and reperfusion injury by restoring autophagy in aged mice.
    International immunopharmacology, 2019, Volume: 74

    Old livers are more damaged by hepatic ischemia and reperfusion (IR) injury than young livers. The aim of this study was to investigate the effects of ischemic and rapamycin preconditioning on IR injury in old livers. Young (8-week-old) and aged (60-week-old) mice were subjected to IR or a sham control procedure. The aged mice were randomly divided into six groups: IR (CON), IR with ischemic preconditioning (IPC), IR with rapamycin preconditioning (RAPA), IR with combined ischemic and rapamycin preconditioning (IPC + RAPA), IR with 3-methyladenine (3-MA), IR with combined ischemic and rapamycin preconditioning with 3-MA pretreatment (IPC + RAPA+3-MA). Liver injury was evaluated 6 h after reperfusion. Hepatocellular autophagy induction was also analyzed by western blotting. The results revealed that aged mice had aggravated liver IR injury as compared to young mice. In aged mice following IR, IPC + RAPA but not IPC or RAPA alleviated liver injury, as evidenced by lower levels of serum ALT, improved preservation of liver architecture with lower Suzuki scores, and decreased caspase-3 activity compared with CON. In addition, western blot analysis revealed increased LC3B II but decreased p62 protein expression levels in the IPC + RAPA group, indicating that autophagic flux was restored by combined ischemic and rapamycin preconditioning. Furthermore, autophagy inhibition by the inhibitor 3-MA abrogated the protective role in the IPC + RAPA group, while no significant effects were observed in the CON group. In conclusions, our results demonstrated that combined ischemic and rapamycin preconditioning protected old livers against IR injury, which was likely attributed to restored autophagy activation.

    Topics: Aging; Animals; Autophagy; Caspase 3; Cells, Cultured; Combined Modality Therapy; Disease Models, Animal; Humans; Immunosuppressive Agents; Ischemic Preconditioning; Liver; Male; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; Reperfusion Injury; Sirolimus

2019
Suppressing the dark side of autophagy.
    Autophagy, 2019, Volume: 15, Issue:10

    Topics: Animals; Animals, Genetically Modified; Autophagy; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Down-Regulation; Humans; Mechanistic Target of Rapamycin Complex 2; Mice; Mice, Knockout; Mitochondrial Membrane Transport Proteins; Mitochondrial Membranes; Mitochondrial Permeability Transition Pore; Protein Serine-Threonine Kinases; Rapamycin-Insensitive Companion of mTOR Protein; Reperfusion Injury; Signal Transduction; Sirolimus; Voltage-Dependent Anion Channel 1

2019
The protective effect of alpha-lipoic acid against brain ischemia and reperfusion injury via mTOR signaling pathway in rats.
    Neuroscience letters, 2018, 04-03, Volume: 671

    Alpha-lipoic Acid(ALA), an endogenous short-chain fatty acid, has been found inducing a protective effect against ischemia and reperfusion(I/R) injury. Recently, mTOR signaling pathway has been proved to involve in the mechanism of I/R injury. In our previous study, we determined that ALA could protect cerebral endothelial cells against I/R injury via mTOR signaling pathway. However, whether ALA can protect against brain I/R injury in vivo and its mechanisms is uncertain. In this study, we try to explore if the ALA treatment can protect against brain I/R injury and confirm the relationship between ALA and mTOR signaling pathway. ALA was administrated to the animals after dMCAo and reperfusion model established with or without rapamycin pre-treatment. The results showed the infarct size was obviously reduced after ALA treatment in acute stage, neurological functions were also improved distinctly. The mTOR signaling pathway was remarkably blocked after brain I/R injury while it could be activated through ALA treatment. However, rapamycin, can abolish the protective effects induced by ALA treatment in both acute and long-term phase. In conclusion, we demonstrate the protective effects induced by ALA treatment against the brain I/R injury in rats and mTOR signaling pathway is required for the protective effects of ALA against brain I/R injury. The results might contribute to the potential clinical application of ALA and provide a potential therapeutic target on ischemic stroke.

    Topics: Animals; Brain Ischemia; Male; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Signal Transduction; Sirolimus; Thioctic Acid; TOR Serine-Threonine Kinases

2018
Dexmedetomidine attenuates renal fibrosis via α2-adrenergic receptor-dependent inhibition of cellular senescence after renal ischemia/reperfusion.
    Life sciences, 2018, Aug-15, Volume: 207

    Renal ischemia/reperfusion (IR) can induce acute kidney injury (AKI), which often progresses to chronic kidney disease (CKD). Dexmedetomidine (Dex), a highly selective α2 adrenergic receptor (α2-AR) agonist, protects against acute renal IR-induced injury. However, the effects of Dex on the transition of AKI to CKD remain unclear. Therefore, we investigated the mechanisms of Dex on renal fibrosis.. Adult male C57BL/6 mice were pretreated with Dex, a specific α2A-adrenergic receptor (AR) blocker (BRL-44408), or a cell senescence inhibitor (rapamycin) in a surgical bilateral renal IR model. The diagnoses of AKI and chronic renal fibrosis were performed by histopathological staining and western blotting. Histopathological changes, cell senescence, tubular fibrotic markers, and the expression of inflammatory factors were studied.. Pretreatment with Dex alleviated renal IR-induced AKI and chronic tubulointerstitial fibrosis in later stages. Similar to the effects of rapamycin, pretreatment with Dex also decreased the number of senescent tubular cells and weakened the protein expression of senescence-associated markers such as p53, p21, and p16. Furthermore, the expression of inflammatory markers was also decreased in Dex-treated IR mice; and these protective effects of Dex could be abolished by treatment with the specific α2A-AR blocker, BRL-44408.. The administration of a single dose of Dex protects against AKI and CKD. Dex inhibits tubular cell senescence and inflammation as well as improves renal fibrosis to moderate the AKI-to-CKD transition. The renal protective potential of Dex may provide a novel treatment strategy for high-risk renal injury patients.

    Topics: Acute Kidney Injury; Adrenergic alpha-2 Receptor Agonists; Animals; Cellular Senescence; Dexmedetomidine; Fibrosis; Imidazoles; Inflammation; Isoindoles; Kidney; Male; Mice; Mice, Inbred C57BL; Receptors, Adrenergic, alpha-2; Reperfusion Injury; Signal Transduction; Sirolimus

2018
Synergistic effect of rapamycin and metformin against germ cell apoptosis and oxidative stress after testicular torsion/detorsion-induced ischemia/reperfusion in rats.
    Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2018, Volume: 105

    The aim of this study was to investigate the effects of rapamycin (rapa) and metformin (met), combined administration on testicular torsion-detorsion (T/D) injury. A total of 108 male rats were divided randomly into six groups (n = 18), control, sham-operated, T/D, T/D + met (100 mg/kg), T/D + rapa (0.25 mg/kg) and T/D + met (100 mg/kg)+rapa (0.25 mg/kg). Except for the control and sham groups, torsion was created by rotating the right testis 720° in a clockwise direction for 1 h. Treatment groups received drug intraperitoneally, 30 min before detorsion. The right testis of 6 animals from each group was excised 4 h after detorsion for the measurement of lipid peroxidation, caspase-3, and antioxidant enzyme activities. Histopathological changes and germ cell apoptosis were determined by measuring mean of seminiferous tubules diameters (MSTD) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) test in rest of animals, 24 h after detorsion. In T/D group tissue malondialdehyde (MDA) level and caspase-3 activity increased and the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) decreased in comparison with the control group after detorsion. Met and rapa separately pre-treatment reduced MDA and caspase-3 levels, normalized antioxidant enzyme activities, reduced germ cell apoptosis and improved the MSTD in comparison with T/D group. However combined administration of met and rapa indicated a significant augmented effect as compared to the individual drug interventions on the reversal of T/D induced oxidative stress, apoptosis, and histologic changes, suggesting a synergistic response. Thus, this study shows that rapa and met combination have significant synergistic effects against oxidative stress and apoptosis and opens up further possibilities for the design of new combinatorial therapies to prevent tissue damage after ischemia-reperfusion (I/R).

    Topics: Animals; Apoptosis; Drug Synergism; Male; Metformin; Oxidative Stress; Rats, Wistar; Reperfusion Injury; Sirolimus; Spermatic Cord Torsion; Testis

2018
Rapamycin mediates mTOR signaling in reactive astrocytes and reduces retinal ganglion cell loss.
    Experimental eye research, 2018, Volume: 176

    Damage and loss of retinal ganglion cells (RGCs) can cause visual impairment. The underlying molecular mechanisms that mediate RGC death in ischemic retinal diseases are still unclear. In this study, we sought to understand the neuroprotective effect of rapamycin, the selective inhibitor of mTORC1, on RGC survival and the cellular mechanics that mediate this effect. Recent studies have reported that the epidermal growth factor (EGF) receptor shows an increase in expression in astrocytes after injury, and this receptor can promote their transformation into reactive astrocytes. Our results, along with previous works from others, show the colocalization of phosphor-EGF receptors with the astrocyte marker glial fibrillary acidic proteins in reactive astrocytes in the injured retina. In our in vitro studies, using primary astrocyte cultures of the optic nerve head of rats, showed that rapamycin significantly blocked EGF-induced mTOR signaling mainly through the PI3K/Akt pathway in primary astrocytes, but not through the MAPK/Erk pathway. Additionally, rapamycin dramatically inhibited the activation of mTOR signaling in our ratinal ischemia-reperfusion (I/R) injury model in vivo. Astrocyte activation was assessed by immunostaining retinal flat mounts or cross sections with antibody against GFAP, and we also used western blots to detect the expression of GFAP. Taken together, these results revealed that rapamycin decreases the activation of astrocytes after retinal ischemia-reperfusion injury. Furthermore, rapamycin can improve retinal RGC survival in rats during I/R, as detected by FluoroGold labeling. Our data reveals the neuroprotective effects of rapamycin in an experimental retina injury model, possibly through decreasing glial-dependent intracellular signaling mechanisms for suppressing apoptosis of RGCs. Our study also presents an approach to targeting reactive astrocytes for the treatment of optic neurodegenerations.

    Topics: Animals; Anti-Bacterial Agents; Apoptosis; Astrocytes; Blotting, Western; Cell Survival; Cells, Cultured; Epidermal Growth Factor; Glial Fibrillary Acidic Protein; Male; Neuroprotective Agents; Optic Disk; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Retinal Diseases; Retinal Ganglion Cells; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2018
Neuroprotective effects of pinocembrin on ischemia/reperfusion-induced brain injury by inhibiting autophagy.
    Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2018, Volume: 106

    Cerebral ischemia/reperfusion (I/R) injury is a common pathological process after cardiac arrest, shock and acute cerebral infarction recanalization, which causes serious injury in brain function. Pinocembrin (Pino), a natural flavonoid at the highest concentration in propolis, exhibited a variety of biological effects, including antitumor, antimicrobial and anti-inflammatory activities. However, the effects of Pino on brain injured after I/R and the mechanisms of its neuroprotective effects remain elusive.. In the present study, we used I/R model rats underwent transient cerebral ischemia inducing by four-vessel occlusion and reperfusion. Pino alone or in combination with autophagy inducer rapamycin (RAPA) was administered to I/R rats. The behavior and cognitive function were evaluated by open field test and Morris water maze test. HE staining was used to determine the survival of hippocampus CA1 pyramidal cells. Three key proteins of autophagy, LC3, Beclin1 and p62, were detected by Western blot.. Our results showed that Pino could significantly reduce the damage of hippocampus CA1 pyramidal neurons and alleviate the impairments of behavior and cognitive function in I/R rats. Pino also decreased the expression of LC3II and Beclin1 and increased the level of p62 in hippocampus CA1 of I/R rats. In addition, Pino also decreased RAPA-induced neuronal damage and excessive activation of autophagy in I/R rats.. Taken together, these results suggested that Pino could protect the brain injury induced by I/R and the potential mechanisms might attribute to inhibition of autophagy activity.

    Topics: Animals; Autophagy; Beclin-1; Behavior, Animal; Brain Ischemia; CA1 Region, Hippocampal; Cognition; Disease Models, Animal; Flavanones; Male; Maze Learning; Microtubule-Associated Proteins; Motor Activity; Neurons; Neuroprotective Agents; Rats, Sprague-Dawley; Reperfusion Injury; Sequestosome-1 Protein; Sirolimus; Time Factors

2018
Evidence that decreased expression of sinusoidal bile acid transporters accounts for the inhibition by rapamycin of bile flow recovery following liver ischemia.
    European journal of pharmacology, 2018, Nov-05, Volume: 838

    Rapamycin is employed as an immunosuppressant following organ transplant and, in patients with hepatocellular carcinoma, to inhibit cancer cell regrowth following liver surgery. Preconditioning the liver with rapamycin to induce the expression of antioxidant enzymes is a potential strategy to reduce ischemia reperfusion (IR) injury. However, pre-treatment with rapamycin inhibits bile flow, especially following ischemia. The aim was to investigate the mechanisms involved in this inhibition. In a rat model of segmental hepatic ischemia and reperfusion, acute administration of rapamycin by intravenous injection did not inhibit the basal rate of bile flow. Pre-treatment of rats with rapamycin for 24 h by intraperitoneal injection inhibited the expression of mRNA encoding the sinusoidal influx transporters Ntcp, Oatp1 and 2 and the canalicular efflux transporter Bsep, and increased expression of canalicular Mrp2. Dose-response curves for the actions of rapamycin on the expression of Bsep and Ntcp in cultured rat hepatocytes were biphasic, and monophasic for effects on Oatp1. In cultured tumorigenic H4IIE liver cells, several bile acid transporters were not expressed, or were expressed at very low levels compared to hepatocytes. In H4IIE cells, rapamycin increased expression of Ntcp, Oatp1 and Mrp2, but decreased expression of Oatp2. It is concluded that the inhibition of bile flow recovery following ischemia observed in rapamycin-treated livers is principally due to inhibition of the expression of sinusoidal bile acid transporters. Moreover, in tumorigenic liver tissue the contribution of tumorigenic hepatocytes to total liver bile flow is likely to be small and is unlikely to be greatly affected by rapamycin.

    Topics: Animals; Bile; Bile Ducts; Carcinoma, Hepatocellular; Carrier Proteins; Cell Line, Tumor; Cholestasis; Disease Models, Animal; Dose-Response Relationship, Drug; Hepatocytes; Humans; Immunosuppressive Agents; Ischemia; Liver; Liver Neoplasms; Liver Transplantation; Male; Membrane Glycoproteins; Rats; Rats, Sprague-Dawley; Rats, Zucker; Reperfusion Injury; Sirolimus; Transplantation Conditioning

2018
Rapamycin and fasting sustain autophagy response activated by ischemia/reperfusion injury and promote retinal ganglion cell survival.
    Cell death & disease, 2018, 09-24, Volume: 9, Issue:10

    Topics: Adaptor Proteins, Signal Transducing; Adenylate Kinase; Animals; Autophagosomes; Autophagy; Autophagy-Related Protein 12; Autophagy-Related Protein 5; Beclin-1; Cell Survival; Fasting; Female; Male; Mice; Mice, Inbred C57BL; Reperfusion Injury; Retina; Retinal Ganglion Cells; Sequestosome-1 Protein; Sirolimus; TOR Serine-Threonine Kinases

2018
Autophagy and Akt in the protective effect of erythropoietin helix B surface peptide against hepatic ischaemia/reperfusion injury in mice.
    Scientific reports, 2018, 10-02, Volume: 8, Issue:1

    Topics: Adenine; Animals; Autophagosomes; Autophagy; Cell Line; Chemical and Drug Induced Liver Injury; Chromones; Cobalt; Disease Models, Animal; Erythropoietin; Humans; Liver; Liver Function Tests; Mice; Mice, Inbred C57BL; Morpholines; Peptide Fragments; Proto-Oncogene Proteins c-akt; Random Allocation; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2018
Rapamycin induces autophagy to alleviate acute kidney injury following cerebral ischemia and reperfusion via the mTORC1/ATG13/ULK1 signaling pathway.
    Molecular medicine reports, 2018, Volume: 18, Issue:6

    Acute kidney injury (AKI) is a clinically common and severe complication of ischemia‑reperfusion (I/R), associated with high morbidity and mortality rates, and prolonged hospitalization. Rapamycin is a type of macrolide, primarily used for anti‑rejection therapy following organ transplantation and the treatment of autoimmune diseases. Rapamycin has been identified to exert a protective effect against AKI induced by renal I/R as an autophagy inducer. However, whether rapamycin preconditioning may relieve AKI following cerebral I/R (CIR) remains to be fully elucidated. The purpose of the present study was to investigate the effects of CIR on the renal system of rats and the role of rapamycin in AKI following CIR. In the present study, a CIR model was established in Sprague‑Dawley rats via a 90‑min period of middle cerebral artery occlusion and 24 h reperfusion, and pretreatment with an intraperitoneal injection of rapamycin (dosage: 1 mg/kg; 0.5 h) prior to CIR. The levels of serum creatinine and blood urea nitrogen (BUN), and the expression of inflammation‑, apoptosis‑ and autophagy‑associated markers were subsequently measured. In addition to certain histopathological alterations to the kidney, it was identified that CIR significantly increased the levels of serum creatinine, BUN, tumor necrosis factor‑α and interleukin‑1β, and significantly induced apoptosis and autophagy. It was observed that rapamycin induced autophagy through the mammalian target of rapamycin complex 1/autophagy‑related 13/unc‑51 like autophagy activating kinase 1 signaling pathway, and that rapamycin pre‑treatment significantly improved renal function and alleviated renal tissue inflammation and cell apoptosis in rats following CIR. In conclusion, the results suggested that rapamycin may alleviate AKI following CIR via the induction of autophagy.

    Topics: Acute Kidney Injury; Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Autophagy; Autophagy-Related Protein-1 Homolog; Autophagy-Related Proteins; Biomarkers; Intracellular Signaling Peptides and Proteins; Kidney Function Tests; Male; Mechanistic Target of Rapamycin Complex 1; Rats; Reperfusion Injury; Signal Transduction; Sirolimus

2018
[Rapamycin treatment starting at 24 h after cerebral ischemia/reperfusion exhibits protective effect on brain injury in rats].
    Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences, 2018, 05-25, Volume: 47, Issue:5

    To investigate whether rapamycin treatment starting at 24 h after cerebral ischemia/reperfusion(I/R) has protective effect on brain injury in rats.. The rat I/R model was established by middle cerebral artery occlusion according to Longa's method. A total of 104 Sprague Dawley rats were randomly divided into sham group, model group, and rapamycin-treated groups (6 h or 24 h after modeling). Neurological function was assessed with neurological severity score (NSS). Triphenyl tetrazolium chloride (TTC) staining and Fluoro-Jade B (FJB) staining were used to examine the infarct volume and neuronal apoptosis, respectively. The expression of p-S6 protein in mTOR signaling pathway was detected by Western blot analysis.. Compared with sham group, NSS of the model group was significantly increased and TTC staining indicated obvious infarct area (all. Rapamycin treatment starting at 24 h after I/R exhibits protective effect on brain injury in rats.

    Topics: Animals; Brain Ischemia; Immunosuppressive Agents; Infarction, Middle Cerebral Artery; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Treatment Outcome

2018
Downregulation of autophagy is associated with severe ischemia-reperfusion-induced acute kidney injury in overexpressing C-reactive protein mice.
    PloS one, 2017, Volume: 12, Issue:9

    C-reactive protein (CRP), was recently reported to be closely associated with poor renal function in patients with acute kidney injury (AKI), but whether CRP is pathogenic or a mere biomarker in AKI remains largely unclear. Impaired autophagy is known to exacerbate renal ischemia-reperfusion injury (IRI). We examined whether the pathogenic role of CRP in AKI is associated with reduction of autophagy. We mated transgenic rabbit CRP over-expressing mice (Tg-CRP) with two autophagy reporter mouse lines, Tg-GFP-LC3 mice (LC3) and Tg-RFP-GFP-LC3 mice (RG-LC3) respectively to generate Tg-CRP-GFP-LC3 mice (PLC3) and Tg-CRP-RFP-GFP-LC3 mice (PRG-LC3). AKI was induced by IRI. Compared with LC3 mice, PLC3 mice developed more severe kidney damage after IRI. Renal tubules were isolated from LC3 mice at baseline for primary culture. OKP cells were transiently transfected with GFP-LC3 plasmid. CRP addition exacerbated lactate dehydrogenase release from both cell types. Immunoblots showed lower LC-3 II/I ratios and higher levels of p62, markers of reduced autophagy flux, in the kidneys of PLC3 mice compared to LC3 mice after IRI, and in primary cultured renal tubules and OKP cells treated with CRP and H2O2 compared to H2O2 alone. Immunohistochemistry showed much fewer LC-3 punctae, and electron microscopy showed fewer autophagosomes in kidneys of PLC3 mice compared to LC3 mice after IRI. Similarly, CRP addition reduced GFP-LC3 punctae induced by H2O2 in primary cultured proximal tubules and in GFP-LC3 plasmid transfected OKP cells. Rapamycin, an autophagy inducer, rescued impaired autophagy and reduced renal injury in vivo. In summary, it was suggested that CRP be more than mere biomarker in AKI, and render the kidney more susceptible to ischemic/oxidative injury, which is associated with down-regulating autophagy flux.

    Topics: Acute Kidney Injury; Animals; Autophagy; Beclin-1; C-Reactive Protein; Disease Models, Animal; Epithelial Cells; Gene Expression; Humans; Kidney Tubules; Mice; Protein Binding; Proto-Oncogene Proteins c-bcl-2; Rabbits; Reperfusion Injury; Severity of Illness Index; Sirolimus

2017
The Effect of Autophagy on Inflammation Cytokines in Renal Ischemia/Reperfusion Injury.
    Inflammation, 2016, Volume: 39, Issue:1

    Acute kidney injury (AKI) is characterized by a rapid loss of kidney function and an antigen-independent inflammatory process that causes tissue damage, which was one of the main manifestations of kidney ischemia/reperfusion (I/R). Recent studies have demonstrated autophagy participated in the pathological process of acute kidney injury. In this study, we discuss how autophagy regulated inflammation response in the kidney I/R. AKI was performed by renal I/R. Autophagy activator rapamycin (Rap) and inhibitor 3-methyladenine (MA) were used to investigate the role of autophagy on kidney function and inflammation response. After the experiment, kidney tissues were obtained for the detection of autophagy-related protein microtubule-associated protein light chain 3(LC3)II, Beclin1, and Rab7 and lysosome-associated membrane protein type (LAMP)2 protein by reverse transcription-polymerase chain reaction (PT-PCR) and Western blotting, and histopathology and tissue injury scores also. The blood was harvested to measure kidney function (creatinine (Cr) and blood urea nitrogen (BUN) levels) after I/R. Cytokines TNF-α, IL-6, HMGB1, and IL-10 were measured after I/R. I/R induced the expression of LC3II, Beclin1, LAMP2, and Rab7. The activation and inhibition of autophagy by rapamycin and 3-MA were promoted and attenuated histological and renal function in renal I/R rats, respectively. Cytokines TNF-α, IL-6, and HMGB1 were decreased, and IL-10 was further increased after activation of autophagy treated in I/R rats, while 3-MA exacerbated the pro-inflammatory cytokines TNF-α, IL-6, HMGB1, and anti-inflammatory cytokine IL-10 in renal I/R. I/R can activated the autophagy, and autophagy increase mitigated the renal injury by decreasing kidney injury score, levels of Cr and BUN after renal I/R, and inflammation response via regulating the balance of pro-inflammation and anti-inflammation cytokines.

    Topics: Acute Kidney Injury; Adenine; Animals; Anti-Inflammatory Agents; Autophagy; Beclin-1; Enzyme Activation; HMGB1 Protein; Inflammation; Interleukin-10; Interleukin-6; Kidney; Lysosomal-Associated Membrane Protein 2; Male; Microtubule-Associated Proteins; rab GTP-Binding Proteins; rab7 GTP-Binding Proteins; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Tumor Necrosis Factor-alpha

2016
Effects of rapamycin pretreatment on blood-brain barrier disruption in cerebral ischemia-reperfusion.
    Neuroscience letters, 2016, 05-04, Volume: 620

    The mammalian target of rapamycin (mTOR) pathway is essential in neuronal survival and repair in cerebral ischemia. Decreases in blood-brain barrier (BBB) disruption are associated with a decrease in neuronal damage in cerebral ischemia. This study was performed to investigate how pre-inhibition of the mTOR pathway with rapamycin would affect BBB disruption and the size of the infarcted cortical area in the early stage of focal cerebral ischemia-reperfusion using quantitative analysis of BBB disruption. Rats were treated with 20mg/kg of rapamycin i.p. once a day for 2days (Rapamycin Group) or vehicle (Control Group) before transient middle cerebral artery (MCA) occlusion. After one hour of MCA occlusion and two hours of reperfusion, the transfer coefficient (Ki) of (14)C-α-aminoisobutyric acid ((14)C-AIB) to measure the degree of BBB disruption and the size of the cortical infarct were determined. Ischemia-reperfusion increased the Ki in the Rapamycin treated (+15%) as well as in the untreated control group (+13%). However, rapamycin pretreatment moderately decreased Ki in the contralateral (-30%) as well as in the ischemic-reperfused (-29%) cortex when compared with the untreated control group. Rapamycin pretreatment substantially increased the percentage of cortical infarct compared with the control group (+56%). Our data suggest that activation of mTOR pathway is necessary for neuronal survival in the early stage of cerebral ischemia-perfusion and that the reason for the enlarged cortical infarct by rapamycin pretreatment may be related to its non-BBB effects on the mTOR pathway.

    Topics: Animals; Blood-Brain Barrier; Brain Infarction; Brain Ischemia; Cerebral Cortex; Male; Permeability; Rats, Inbred F344; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

2016
Role of autophagy in the bimodal stage after spinal cord ischemia reperfusion injury in rats.
    Neuroscience, 2016, 07-22, Volume: 328

    Autophagy plays an important role in spinal cord ischemia reperfusion (I/R) injury, but its neuroprotective or neurodegenerative role remains controversial. The extent and persistence of autophagy activation may be the critical factor to explain the opposing effects. In this study, the different roles and action mechanisms of autophagy in the early and later stages after I/R injury were investigated in rats. Thespinal cord I/R injury was induced by 14-min occlusion of the aortic arch, after which rats were treated with autophagic inhibitor (3-methyladenine, 3-MA) or agonist (rapamycin) immediately or 48h following the injury. Autophagy markers, microtubule-associated protein light chain 3-II (LC3-II) and Beclin 1 increased and peaked at the early stage (8h) and the later stage (72h) after spinal cord I/R injury. Beclin 1 was mostly expressed in neurons, but was also expressed to an extent in astrocytes, microglia and vascular endothelial cells. 8h after injury, rats treated with 3-MA showed a decrease in the hind-limb Basso-Beattie-Bresnahan (BBB) motor function scores, surviving motor neurons, and B-cell lymphoma-2 (Bcl-2) expression, and increase in the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells, Bcl-2-associated X protein (Bax), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) expression, and activation of microglia, while those treated with rapamycin showed opposing effects. However, 72h after injury, rats treated with 3-MA improved the BBB scores, and the surviving motor neurons, and reduced the autophagic cell death, while those treated with rapamycin had adverse effects. These findings provide the first evidence that early activated autophagy alleviates spinal cord I/R injury via inhibiting apoptosis and inflammation; however later excessively elevated autophagy aggravates I/R injury through inducing autophagic cell death.

    Topics: Adenine; Animals; Apoptosis; Autophagy; Central Nervous System Agents; Disease Models, Animal; Male; Motor Activity; Neuroimmunomodulation; Random Allocation; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Spinal Cord; Spinal Cord Ischemia

2016
Role of mechanistic target of rapamycin (mTOR) in renal function and ischaemia-reperfusion induced kidney injury.
    Clinical and experimental pharmacology & physiology, 2016, Volume: 43, Issue:11

    Despite the presence of many studies on the role of mechanistic target of rapamycin (mTOR) in cardiorenal tissues, the definitive role of mTOR in the pathogenesis of renal injury subsequent to ischaemia-reperfusion (IR) remains unclear. The aims of the current study were to characterize the role of mTOR in normal kidney function and to investigate the role of mTOR activation in IR-induced kidney injury. In euvolemic anaesthetized rats, treatment with the mTOR inhibitor rapamycin increased blood pressure (121 ± 2 to 144 ± 3 mmHg; P<.05), decreased glomerular filtration rate (GFR; 1.6 ± 0.3 to 0.5 ± 0.2 mL/min; P<.05) and increased urinary sodium excretion (UNaV; 14 ± 1 to 109 ± 25 mmol/L per hour; P<.05). In rats subjected to IR, autophagy induction, p-mTOR expression and serum creatinine increased (1.9 ± 0.2 to 3 ± 0.3 mg/dL; P<.05); treatment with rapamycin blunted p-mTOR expression but further increased autophagy induction and serum creatinine (3 ± 0.3 to 5 ± 0.6 mg/dL; P<.05). In contrast, clenbuterol, an mTOR activator, blunted the effect of rapamycin on serum creatinine (4 ± 0.6 vs 2.3 ± 0.3 mg/dL; P<.05), autophagy induction and p-mTOR expression. IR also increased 24 hour protein excretion (9 ± 3 to 17 ± 2 mg/day; P<.05) and kidney injury molecule-1 (KIM-1) expression, and rapamycin treatment further increased KIM-1 expression. Clenbuterol exacerbated protein excretion (13 ± 2 to 26 ± 4 mg/day; P<.05) and antagonized the effect of rapamycin on KIM-1 expression. Histopathological data demonstrated kidney injury in IR rats that was worsened by rapamycin treatment but attenuated by clenbuterol treatment. Thus, mTOR signalling is crucial for normal kidney function and protecting the kidney against IR injury through autophagy suppression.

    Topics: Animals; Autophagy; Female; Glomerular Filtration Rate; Kidney; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; TOR Serine-Threonine Kinases

2016
Associations between autophagy, the ubiquitin-proteasome system and endoplasmic reticulum stress in hypoxia-deoxygenation or ischemia-reperfusion.
    European journal of pharmacology, 2016, Nov-15, Volume: 791

    The activation of autophagy has been demonstrated to exert protective roles during hypoxia-reoxygenation (H/R)-induced brain injuries. This study aimed to investigate whether and how preconditioning with a proteasome inhibitor (MG-132), a proteasome promoter (Adriamycin, ADM), an autophagy inhibitor (3-methyladenine, 3-MA) and an autophagy promoter (Rapamycin, Rap) affected endoplasmic reticulum stress (ERS), the ubiquitin-proteasome system (UPS), autophagy, inflammation and apoptosis. Ubiquitin protein and 26S proteasome activity levels were decreased by MG-132 pretreatment but increased by ADM pretreatment at 2h, 4h and 6h following H/R treatment. MG-132 pretreatment led to the increased expression of autophagy-related genes, ER stress-associated genes and IκB but decreased the expression levels of NF-κB and caspase-3. ADM pretreatment led to the decreased expression of autophagy-related genes, ERS-associated genes and IκB but increased the expression of NF-κB and caspase-3. Pretreatment with 3-MA reduced the expression of autophagy-related genes, autophagy and UPS co-related genes, as well as apoptosis-related although the latter was increased by Rap pretreatment at 2h, 4h and 6h following H/R treatment. In vivo, pretreatment of rats with ADM, MG-132, 3-MA or Rap followed by ischemia-reperfusion (I/R) treatment resulted in similar changes. Proteasome inhibition preconditioning strengthened autophagy and ER stress but decreased apoptosis and inflammation. Autophagy promotion preconditioning exhibited similar changes. The combination of a proteasome inhibitor and an autophagy promoter might represent a new possible therapy to treat H/R or I/R injury-related diseases.

    Topics: Adenine; Animals; Apoptosis; Autophagy; Cell Hypoxia; Cell Line; Cell Survival; Doxorubicin; Endoplasmic Reticulum Stress; Histone Deacetylase 6; Histone Deacetylases; Leupeptins; Lung; Male; NF-kappa B; Oxygen; Proteasome Endopeptidase Complex; Rats; Reperfusion Injury; Sirolimus; Ubiquitin

2016
Autophagy decreases alveolar macrophage apoptosis by attenuating endoplasmic reticulum stress and oxidative stress.
    Oncotarget, 2016, Dec-27, Volume: 7, Issue:52

    To study the impact of autophagy on alveolar macrophage apoptosis and its mechanism in the early stages of hypoxia, we established a cell hypoxia-reoxygenation model and orthotopic left lung ischemia-reperfusion model. Rat alveolar macrophages stably expressing RFP-LC3 were treated with autophagy inhibitor (3-methyladenine, 3-MA) or autophagy promoter (rapamycin), followed by hypoxia-reoxygenation treatment 2 h, 4 h or 6 h later. Twenty Sprague-Dawley male rats were randomly divided into four different groups: no blocking of left lung hilum (model group), left lung hilum blocked for 1h with DMSO lavage (control group), left lung hilum blocked for 1 h with 100 ml/kg 3-MA (5 μmol/L) lavage (3-MA group), and left lung hilum blocked for 1 h with 100 ml/kg rapamycin (250 nmol/L) lavage (rapamycin group). Rapamycin decreased the unfolded protein response, which reduced endoplasmic reticulum stress-mediated apoptosis in the presence of oxygen deficiency. Rapamycin increased superoxide dismutase activities and decreased malondialdehyde levels, whereas 3-MA decreased superoxide dismutase activities and increased malondialdehyde levels. Thus, autophagy decreases alveolar macrophage apoptosis by attenuating endoplasmic reticulum stress and oxidative stress in the early stage of hypoxia in vitro and in vivo. This could represent a new approach to protecting against lung ischemia-reperfusion injury.

    Topics: Adenine; Animals; Apoptosis; Autophagy; Caspase 3; Cell Hypoxia; Cells, Cultured; Endoplasmic Reticulum Stress; Macrophages, Alveolar; Male; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Superoxide Dismutase

2016
Rapamycin protection of livers from ischemia and reperfusion injury is dependent on both autophagy induction and mammalian target of rapamycin complex 2-Akt activation.
    Transplantation, 2015, Volume: 99, Issue:1

    Although rapamycin (RPM) have been studied extensively in ischemia models, its functional mechanisms remains to be defined.. We determined how RPM impacted the pathogenesis of ischemia-reperfusion injury (IRI) in a murine liver partial warm ischemia model, with emphasis on its regulation of hepatocyte death.. Rapamycin protected livers from IRI in the presence of fully developed liver inflammatory immune response. Rapamycin enhanced liver autophagy induction at the reperfusion stage. Dual mammalian (mechanistic) target of rapamycin (mTOR)1/2 inhibitor Torin 1, despite its ability to induced autophagy, failed to protect livers from IRI. The treatment with RPM, but not Torin 1, resulted in the enhanced activation of the mTORC2-Akt signaling pathway activation in livers after reperfusion. Inactivation of Akt by Triciribine abolished the liver protective effect of RPM. The differential cytoprotective effect of RPM and Torin 1 was confirmed in vitro in hepatocyte cultures. Rapamycin, but not Trin 1, protected hepatocytes from stress and tumor necrosis factor-α induced cell death; and inhibition of autophagy by chloroquine or Akt by Triciribine abolished RPM-mediated cytoprotection.. Rapamycin protected livers from IRI by both autophagy and mTORC2-Akt activation mechanisms.

    Topics: Animals; Autophagy; Cell Line; Cytoprotection; Disease Models, Animal; Endoplasmic Reticulum Stress; Enzyme Activation; Hepatocytes; Liver; Liver Diseases; Male; Mechanistic Target of Rapamycin Complex 2; Mice, Inbred C57BL; Multiprotein Complexes; Naphthyridines; Protective Agents; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Reperfusion Injury; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha; Warm Ischemia

2015
Electroacupuncture pretreatment induces tolerance against cerebral ischemia/reperfusion injury through inhibition of the autophagy pathway.
    Molecular medicine reports, 2015, Volume: 11, Issue:6

    Electroacupuncture (EA) pretreatment has been reported to induce tolerance against cerebral ischemia/reperfusion (I/R) injury; however, the mechanisms underlying the beneficial effects of EA remain to be elucidated. Increasing evidence has suggested that excess activation of autophagy is important in I/R injury. The present study aimed to investigate the hypothesis that EA pretreatment‑induced tolerance to cerebral I/R injury was mediated by inhibition of the autophagy pathway. Rats were treated with EA at the acupoint 'Baihui (GV20)' 30 min/day, for five consecutive days prior to the induction of focal cerebral ischemia for 120 min by middle cerebral artery occlusion. Levels of autophagy, cerebral apoptosis, infarct volumes, brain water content and motor deficit were evaluated 12 h following I/R. The autophagy inducer rapamycin was used to investigate the role of autophagy in mediating neuroprotective effects. The results showed that the number of autophagosomes and the expression of the marker proteins of autophagy, including microtubule‑associated protein 1A light chain 3 (LC3)‑II and Beclin 1 were significantly increased 12 h post‑I/R. EA pretreatment decreased the expression of autophagy markers and the number of autophagosomes in the ischemic cortex. In addition, EA pretreatment inhibited neuronal apoptosis, reduced infarct volume and water content, as well as improved neurological outcome of rats following I/R. Furthermore, the reduced expression of LC3‑II and Beclin 1 and the neuroprotective effects were reversed by the autophagy inducer rapamycin. In conclusion, the results of the present study demonstrated that EA pretreatment protected the brain against I/R injury via inhibition of the autophagy process.

    Topics: Acupuncture Points; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Brain; Disease Models, Animal; Electroacupuncture; Male; Microscopy, Electron, Transmission; Microtubule-Associated Proteins; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2015
Rapamycin protects cardiomyocytes against anoxia/reoxygenation injury by inducing autophagy through the PI3k/Akt pathway.
    Journal of Huazhong University of Science and Technology. Medical sciences = Hua zhong ke ji da xue xue bao. Yi xue Ying De wen ban = Huazhong keji daxue xuebao. Yixue Yingdewen ban, 2015, Volume: 35, Issue:1

    The purpose of this study was to investigate the potential cardioprotection roles of Rapamycin in anoxia/reoxygenation (A/R) injury of cardiomyocytes through inducing autophagy, and the involvement of PI3k/Akt pathway. We employed simulated A/R of neonatal rat ventricular myocytes (NRVM) as an in vitro model of ischemial/reperfusion (I/R) injury to the heart. NRVM were pretreated with four different concentrations of Rapamycin (20, 50, 100, 150 μmol/L), and pretreated with 10 mmol/L 3-methyladenine (3MA) for inhibiting autophagy during A/R. Then, Western blot analysis was used to examine variation in the expression of LC3-II, LC3-I, Bim, caspase-3, p-PI3KI, PI3KI, p-Akt and Akt. In our model, Rapamycin had a preferential action on autophagy, increasing the expression of LC3-II/LC3-I, whereas decreasing the expression of Bim and caspase-3. Moreover, our results also demonstrated that Rapamycin inhibited the activation of p-PI3KI and enhanced the activation of p-Akt. It is concluded that Rapamycin has a cardioprotection effect by inducing autophagy in a concentration-dependent manner against apopotosis through PI3K/Akt signaling pathway during A/R in NRVM.

    Topics: Animals; Autophagy; Base Sequence; Cells, Cultured; DNA Primers; Myocytes, Cardiac; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Real-Time Polymerase Chain Reaction; Reperfusion Injury; Sirolimus

2015
p53 inhibition provides a pivotal protective effect against ischemia-reperfusion injury in vitro via mTOR signaling.
    Brain research, 2015, Apr-24, Volume: 1605

    Tumor suppressor p53 has recently been reported to have numerous functions independent of tumorigenesis, including neuronal survival during ischemia. The mammalian target of rapamycin (mTOR) signaling pathway plays a central role in the regulation of metabolism, cell growth, development, and cell survival. Our recent work has demonstrated the neuroprotective effects of the mTOR pathway. Considering that p53 is also an important regulator of mTOR, to further clarify the role of p53 and the mTOR signaling pathway in neuronal ischemic-reperfusion injury, we used mouse primary mixed cultured neurons with an oxygen glucose deprivation (OGD) model to mimic an ischemic-reperfusion injury in vitro. A lentiviral system was also used to inhibit or overexpress p53 to determine whether p53 alteration affects OGD and reperfusion injury. Our results show that activated p53 was induced and it suppressed mTOR expression in primary mixed cultured neurons after OGD and reperfusion. Inhibiting p53, using either a chemical inhibitor or lentiviral-mediated shRNA, exhibited neuroprotective effects in primary cultured neurons against OGD and reperfusion injury through the upregulation of mTOR activity. Such protective effects could be reversed by rapamycin, an mTOR inhibitor. Conversely, p53 overexpression tended to exacerbate the detrimental effects of OGD injury by downregulating mTOR activity. These results suggest that p53 inhibition has a pivotal protective effect against an in vitro ischemia-reperfusion injury via mTOR signaling and provides a potential and promising therapeutic target for stroke treatment.

    Topics: Animals; Benzothiazoles; Cells, Cultured; Female; Mice; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Pregnancy; Reperfusion Injury; Signal Transduction; Sirolimus; Toluene; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53

2015
Telomerase deficiency delays renal recovery in mice after ischemia-reperfusion injury by impairing autophagy.
    Kidney international, 2015, Volume: 88, Issue:1

    The aged population suffers increased morbidity and higher mortality in response to episodes of acute kidney injury (AKI). Aging is associated with telomere shortening, and both telomerase reverse transcriptase (TerT) and RNA (TerC) are essential to maintain telomere length. To define a role of telomerase deficiency in susceptibility to AKI, we used ischemia/reperfusion injury in wild-type mice or mice with either TerC or TerT deletion. Injury induced similar renal impairment at day 1 in each genotype, as assessed by azotemia, proteinuria, acute tubular injury score, and apoptotic tubular epithelial cell index. However, either TerC or TerT knockout significantly delayed recovery compared with wild-type mice. Electron microscopy showed increased autophagosome formation in renal tubular epithelial cells in wild-type mice but a significant delay of their development in TerC and TerT knockout mice. There were also impeded increases in the expression of the autophagosome marker LC3 II, prolonged accumulation of the autophagosome protein P62, an increase of the cell cycle regulator p16, and greater activation of the mammalian target of rapamycin (mTOR) pathway. The mTORC1 inhibitor, rapamycin, partially restored the ischemia/reperfusion-induced autophagy response, without a significant effect on either p16 induction or tubule epithelial cell proliferation. Thus, muting the maintenance of normal telomere length in mice impaired recovery from AKI, owing to an increase in tubule cell senescence and impairment of mTOR-mediated autophagy.

    Topics: Acute Kidney Injury; Aging; Animals; Apoptosis; Autophagy; Blood Urea Nitrogen; Cell Proliferation; Cells, Cultured; Cyclin-Dependent Kinase Inhibitor p16; Disease Models, Animal; Epithelial Cells; Kidney; Kidney Tubules, Proximal; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Regeneration; Reperfusion Injury; RNA; Signal Transduction; Sirolimus; Telomerase; Telomere Shortening; TOR Serine-Threonine Kinases

2015
Regulation on Beclin-1 expression by mTOR in CoCl2-induced HT22 cell ischemia-reperfusion injury.
    Brain research, 2015, Jul-21, Volume: 1614

    It has been reported that cerebral ischemia/reperfusion (I/R) injury can activate autophagy. However, the role of autophagy in cerebral I/R injury remains controversy. Two major proteins, mTOR and Beclin-1, govern the formation of autophagosomes to regulate autophagy activity. However, the cross-talking between Beclin-1 and mTOR in cerebral I/R injury remains elusive. In this study, global cerebral I/R injury animal model and focal cerebral I/R injury animal model were induced to test the variation of Beclin-1 level in vivo. To further confirm the variation of Beclin-1 level and investigate the cross-talking between Beclin-1 and mammalian target of rapamycin (mTOR) in I/R injury, we used cobalt chloride (CoCl2) to develop an I/R injury cell model in HT22 cell line. Our data showed that the levels of Beclin-1 and phosphorylated mammalian target of rapamycin (p-mTOR) were clearly induced by I/R injury in vitro. And the time course studies suggested that the Beclin-1 and mTOR may have coordinated regulation in ischemia stages but not in reperfusion stages. Moreover, inhibitor of mTOR could prevent Beclin-1 decreasing, but this prevention may play opposite roles in different stages of I/R injury. We conclude that this study represents a major advance in our understanding of the cross-talking of two key proteins, Beclin-1 and mTOR, in autophagy and the role of autophagy in cerebral I/R injury.

    Topics: Analysis of Variance; Animals; Antimutagenic Agents; Apoptosis Regulatory Proteins; Beclin-1; Brain Ischemia; Cell Line; Cell Survival; Cobalt; Disease Models, Animal; Dose-Response Relationship, Drug; Gene Expression Regulation; Male; Mice; Neurons; Phosphorylation; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2015
Autophagy activation attenuates renal ischemia-reperfusion injury in rats.
    Experimental biology and medicine (Maywood, N.J.), 2015, Volume: 240, Issue:12

    Ischemia-reperfusion (I/R) injury is a leading cause of acute kidney injury (AKI), which is a common clinical complication but lacks effective therapies. This study investigated the role of autophagy in renal I/R injury and explored potential mechanisms in an established rat renal I/R injury model. Forty male Wistar rats were randomly divided into four groups: Sham, I/R, I/R pretreated with 3-methyladenine (3-MA, autophagy inhibitor), or I/R pretreated with rapamycin (autophagy activator). All rats were subjected to clamping of the left renal pedicle for 45 min after right nephrectomy, followed by 24 h of reperfusion. The Sham group underwent the surgical procedure without ischemia. 3-MA and rapamycin were injected 15 min before ischemia. Renal function was indicated by blood urea nitrogen and serum creatinine. Tissue samples from the kidneys were scored histopathologically. Autophagy was indicated by light chain 3 (LC3), Beclin-1, and p62 levels and the number of autophagic vacuoles. Apoptosis was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method and expression of caspase-3. Autophagy was activated after renal I/R injury. Inhibition of autophagy by 3-MA before I/R aggravated renal injury, with worsened renal function, higher renal tissue injury scores, and more tubular apoptosis. In contrast, rapamycin pretreatment ameliorated renal injury, with improved renal function, lower renal tissue injury scores, and inhibited apoptosis based on fewer TUNEL-positive cells and lower caspase-3 expression. Our results demonstrate that autophagy could be activated during I/R injury and play a protective role in renal I/R injury. The mechanisms were involved in the regulation of several autophagy and apoptosis-related genes. Furthermore, autophagy activator may be a promising therapy for I/R injury and AKI in the future.

    Topics: Acute Kidney Injury; Adenine; Animals; Apoptosis; Autophagy; Blood Urea Nitrogen; Caspase 3; Creatinine; Disease Models, Animal; In Situ Nick-End Labeling; Male; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus

2015
Microsphere-Based Rapamycin Delivery, Systemic Versus Local Administration in a Rat Model of Renal Ischemia/Reperfusion Injury.
    Pharmaceutical research, 2015, Volume: 32, Issue:10

    The increasing prevalence and treatment costs of kidney diseases call for innovative therapeutic strategies that prevent disease progression at an early stage. We studied a novel method of subcapsular injection of monodisperse microspheres, to use as a local delivery system of drugs to the kidney.. We generated placebo- and rapamycin monodisperse microspheres to investigate subcapsular delivery of drugs. Using a rat model of acute kidney injury, subcapsular injection of placebo and rapamycin monodisperse microspheres (monospheres) was compared to subcutaneous injection, mimicking systemic administration.. We did not find any adverse effects related to the delivery method. Irrespective of the injection site, a similar low dose of rapamycin was present in the circulation. However, only local intrarenal delivery of rapamycin from monospheres led to decreased macrophage infiltration and a significantly lower amount of myofibroblasts in the kidney, where systemic administration did not. Local delivery of rapamycin did cause a transient increase in the deposition of collagen I, but not of collagen III.. We conclude that therapeutic effects can be increased when rapamycin is delivered subcapsularly by monospheres, which, combined with low systemic concentrations, may lead to an effective intrarenal delivery method.

    Topics: Animals; Drug Delivery Systems; Kidney; Kidney Diseases; Male; Microspheres; Rats; Rats, Inbred F344; Reperfusion Injury; Sirolimus

2015
Autophagy protects renal tubular cells against ischemia / reperfusion injury in a time-dependent manner.
    Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology, 2015, Volume: 36, Issue:1

    Autophagy is a dynamic catabolic process that maintains cellular homeostasis. Whether it plays a role in promoting cell survival or cell death in the process of renal ischemia/reperfusion (I/R) remains controversial, partly because renal autophagy is usually examined at a certain time point. Therefore, monitoring of the whole time course of autophagy and apoptosis may help better understand the role of autophagy in renal I/R.. Autophagy and apoptosis were detected after mice were subjected to bilateral renal ischemia followed by 0-h to 7-day reperfusion, exposure of TCMK-1 cells to 24-h hypoxia, and 2 to 24-h reoxygenation. The effect of autophagy on apoptosis was assessed in the presence of autophagy inhibitor 3-methyladenine (3-MA) and autophagy activator rapamycin.. Earlier than apoptosis, autophagy increased from 2-h reperfusion, reached the maximum at day 2, and then began declining from day 3 when renal damage had nearly recovered to normal. Exposure to 24-h hypoxia induced autophagy markedly, but it decreased drastically after 4 and 8-h reoxygenation, which was accompanied with increased cell apoptosis. Inhibition of autophagy with 3-MA increased the apoptosis of renal tubular cells during I/R in vivo and hypoxia/reoxygenation (H/R) in vitro. In contrast, activation of autophagy by rapamycin significantly alleviated renal tissue damage and tubular cell apoptosis in the two models.. Autophagy was induced in a time-dependent manner and occurred earlier than the onset of cell apoptosis as an early response that played a renoprotective role during renal I/R and cell H/R. Up-regulation of autophagy may prove to be a potential strategy for the treatment of acute kidney injury.

    Topics: Adenine; Animals; Apoptosis; Autophagy; Cell Survival; Cells, Cultured; Gene Expression Regulation; Kidney Tubules; Male; Mice; Reperfusion Injury; Sirolimus; Time Factors

2015
Rapamycin Improves Mortality Following Intestinal Ischemia-Reperfusion via the Inhibition of Remote Lung Inflammation in Mice.
    Digestion, 2015, Volume: 92, Issue:4

    Acute-phase intestinal ischemia-reperfusion (I-R) injury can result in multiple organ failure, which may sometimes be fatal. However, no reliable treatment for this clinical state is available. Rapamycin has been reported to protect heart, brain and kidney against I-R injury. The aim of this study was to examine whether rapamycin could protect mice against I-R-induced intestinal and remote organ injury.. Ischemia was induced in the intestine of C57BL/6 mice by occluding the superior mesenteric artery for 1 h. Mice received rapamycin at a dose of 5 mg/kg or vehicle by the intraperitoneal injection 1 h before ischemia. The survival rate, inflammatory responses in the intestine and the lung, bacteria cultured from lung tissue and the phagocytic capacity of alveolar macrophages were examined.. Treatment with rapamycin improved survival rate after intestinal I-R. Histological and biochemical parameters of I-R-induced intestinal injury/inflammation were similar in both rapamycin-treated and untreated mice. However, signs of lung injury/inflammation were significantly attenuated in rapamycin-treated mice compared to control mice. The reduction of lung bacteria and the increase in phagocytic activity were accompanied in mice treated with rapamycin.. Rapamycin improved mortality following intestinal I-R via the inhibition of remote lung inflammation in mice.

    Topics: Animals; Anti-Bacterial Agents; Inflammation; Injections, Intraperitoneal; Intestinal Diseases; Intestines; Lung; Macrophages, Alveolar; Male; Mice; Mice, Inbred C57BL; Reperfusion Injury; Sirolimus; Survival Rate

2015
New autophagy reporter mice reveal dynamics of proximal tubular autophagy.
    Journal of the American Society of Nephrology : JASN, 2014, Volume: 25, Issue:2

    The accumulation of autophagosomes in postischemic kidneys may be renoprotective, but whether this accumulation results from the induction of autophagy or from obstruction within the autophagic process is unknown. Utilizing the differential pH sensitivities of red fluorescent protein (RFP; pKa 4.5) and enhanced green fluorescent protein (EGFP; pKa 5.9), we generated CAG-RFP-EGFP-LC3 mice to distinguish early autophagic vacuoles from autolysosomes. In vitro and in vivo studies confirmed that in response to nutrient deprivation, renal epithelial cells in CAG-RFP-EGFP-LC3 mice produce autophagic vacuoles expressing RFP and EGFP puncta. EGFP fluorescence diminished substantially in the acidic environment of the autolysosomes, whereas bright RFP signals remained. Under normal conditions, nephrons expressed few EGFP and RFP puncta, but ischemia-reperfusion injury (IRI) led to dynamic changes in the proximal tubules, with increased numbers of RFP and EGFP puncta that peaked at 1 day after IRI. The number of EGFP puncta returned to control levels at 3 days after IRI, whereas the high levels of RFP puncta persisted, indicating autophagy initiation at day 1 and autophagosome clearance during renal recovery at day 3. Notably, proliferation decreased in cells containing RFP puncta, suggesting that autophagic cells are less likely to divide for tubular repair. Furthermore, 87% of proximal tubular cells with activated mechanistic target of rapamycin (mTOR), which prevents autophagy, contained no RFP puncta. Conversely, inhibition of mTOR complex 1 induced RFP and EGFP expression and decreased cell proliferation. In summary, our results highlight the dynamic regulation of autophagy in postischemic kidneys and suggest a role of mTOR in autophagy resolution during renal repair.

    Topics: Acute Kidney Injury; Animals; Autophagy; Cells, Cultured; Chloroquine; Culture Media; Epithelial Cells; Female; Genes, Reporter; Green Fluorescent Proteins; Hydrogen-Ion Concentration; Kidney Tubules, Proximal; Luminescent Proteins; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Transgenic; Microtubule-Associated Proteins; Multiprotein Complexes; Phagosomes; Recombinant Fusion Proteins; Red Fluorescent Protein; Regeneration; Reperfusion Injury; Sirolimus; TOR Serine-Threonine Kinases; Vacuoles

2014
Melatonin inhibits mTOR-dependent autophagy during liver ischemia/reperfusion.
    Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology, 2014, Volume: 33, Issue:1

    Autophagy is a self-digestion system responsible for maintaining cellular homeostasis and interacts with reactive oxygen species produced during ischemia/reperfusion (I/R). Melatonin (MLT) is a potent and endogenous anti-oxidant that has beneficial effects in liver I/R injury. In this study, we examined the cytoprotective mechanisms of MLT in liver I/R, focusing on autophagic flux and associated signaling pathways.. Male C57BL/6 mice were subjected to 70% liver ischemia for 60 min followed by reperfusion. MLT (10 mg/kg, i.p.) was injected 15 min prior to ischemia and again immediately before reperfusion. Rapamycin (Rapa, 1 mg/kg, i.p.), which induces autophagy, was injected 1.5 h before ischemia.. Liver I/R increased autophagic flux as indicated by the accumulation of LC3-II and degradation of sequestosome1/p62. This increase was attenuated by MLT. Likewise, electron microscopic analysis showed that autophagic vacuoles were increased in livers of mice exposed to I/R, which was attenuated by MLT. I/R decreased phosphorylation of mammalian target of rapamycin (mTOR) and 4E-BP1 and 70S6K, downstream molecules of the mTOR pathway, but increased expression of calpain 1 and calpain 2. MLT attenuated the decrease in mTOR, 4E-BP1 and 70S6K phosphorylation. Pretreatment of Rapa reversed the effect of MLT on autophagic flux as well as mTOR pathway.. Our findings suggest that MLT downregulates autophagy via activation of mTOR signaling, which may in turn contribute to its protective effects in liver I/R injury.

    Topics: Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Calpain; Hepatocytes; Liver; Melatonin; Mice, Inbred C57BL; Oxidative Stress; Protective Agents; Reperfusion Injury; Sirolimus; Time Factors; TOR Serine-Threonine Kinases

2014
Autophagic effect of programmed cell death 5 (PDCD5) after focal cerebral ischemic reperfusion injury in rats.
    Neuroscience letters, 2014, Apr-30, Volume: 566

    Former studies indicated that programmed cell death 5 (PDCD5) protein could accelerate the process of apoptosis in response to some stimuli in various kinds of cells via the intrinsic or extrinsic pathway. In this study, we aimed to demonstrate for the first time that protein level of PDCD5 are related to autophagic activity after focal ischemic brain injury in rats. One hundred and twenty-five Sprague-Dawley rats (male) were randomly divided into the following groups: Sham operated, Middle Cerebral Artery Occlusion/Reperfusion (MCAO), MCAO+Control siRNA and MCAO+PDCD5 siRNA. Outcome measurements include neurobehavioral outcomes, brain infarct volume, brain water content, BBB disruption, MRI and double fluorescence labeling. Western blot and histopathophysiological techniques were used to measure the expression of PDCD5 and some pro-autophagic proteins such as Beclin 1 and the LC3-II/LC3-I ratio. The study found that decreased PDCD5 expression via intracerebroventricular injection of PDCD5 siRNA significantly improved the neurobehavioral outcome, reduced the infarct ratio, cerebral edema and BBB disruption. These results were associated with decreased expression of Beclin 1 and the LC3-II/LC3-I ratio in the penumbra area. Rapamycin, an inducer of autophagy, partially weakened the effect of PDCD5 siRNA. In conclusion, this study suggested that PDCD5 was a key regulator of autophagy that might play an important role following MCAO injury.

    Topics: Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Blood-Brain Barrier; Brain Edema; Brain Infarction; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Male; Microtubule-Associated Proteins; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Small Interfering; Sirolimus

2014
Protective effect of everolimus on renal ischemia reperfusion injury in rats.
    Saudi journal of kidney diseases and transplantation : an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia, 2014, Volume: 25, Issue:2

    The aim of this study was to determine the effect of everolimus and tacrolimus pretreatments on renal morphology and function in a rat ischemia reperfusion (I/R) model. Twenty-eight male Sprague-Dawley rats were randomly assigned to saline + sham operation, saline + I/R (IR), tacrolimus + I/R (TRL + I/R) and everolimus + I/R (ERL + I/R) groups. Saline and active treatments were administered intraperitoneally for seven consecutive days before the surgery. The suprarenal aorta was clamped to achieve warm ischemia, except in the sham group. Right nephrectomy was performed in all animals and histology was examined. Renal function was assessed on post-operative Day 7 by Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy, glomerular filtration rate (GFR) and serum biochemistry. Both everolimus and tacrolimus preserved serum creatinine and blood urea nitrogen levels, but only everolimus preserved GFR (0.74 ± 0.36, 1.20 ± 0.37 and 2.24 ± 0.32 mL/min for I/R, TRL + I/R and ERL + I/R, respectively, P < 0.001). %ID values for sham, I/R, TRL + I/R and ERL + I/R were 55 ± 3, 47 ± 4, 45 ± 6 and 62 ± 7 (P < 0.001). On histologic evaluation, ERL + I/R showed less tubular damage and necrosis than I/R, as well as TRL + I/R. Within the confines of this rat warm ischemia model, everolimus pre-treatment was useful in preserving renal function following I/R injury. The possibility of using everolimus as a pre-conditioning agent for I/R injury in kidney transplantation should be further explored.

    Topics: Animals; Blood Urea Nitrogen; Creatinine; Disease Models, Animal; Everolimus; Glomerular Filtration Rate; Immunosuppressive Agents; Ischemic Preconditioning; Kidney; Kidney Transplantation; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Tacrolimus; Warm Ischemia

2014
Autophagy induction does not protect retina against apoptosis in ischemia/reperfusion model.
    Advances in experimental medicine and biology, 2014, Volume: 801

    The role played by autophagy after ischemia/reperfusion (I/R) in the retina remains unknown. Our study investigated whether ischemic injury in the retina, which causes an energy crisis, would induce autophagy. Retinal ischemia was induced by elevation of the intraocular pressure and modulation of autophagic markers was analyzed at the protein levels in an early and late phase of recovery. Following retinal ischemia an increase in LC3BII was first observed in the early phase of recovery but did not stay until the late phase of recovery. Post-ischemic induction of autophagy by intravitreal rapamycin administration did not provide protection against the lesion induced by the ischemic stress. On the contrary, an increase in the number of apoptotic cells was observed following I/R in the rapamycin treated retinas.

    Topics: Animals; Apoptosis; Autophagy; Disease Models, Animal; Immunosuppressive Agents; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Retina; Retinal Diseases; Sirolimus

2014
Rapamycin alleviates brain edema after focal cerebral ischemia reperfusion in rats.
    Immunopharmacology and immunotoxicology, 2014, Volume: 36, Issue:3

    Brain edema is a major consequence of cerebral ischemia reperfusion. However, few effective therapeutic options are available for retarding the brain edema progression after cerebral ischemia. Recently, rapamycin has been shown to produce neuroprotective effects in rats after cerebral ischemia reperfusion. Whether rapamycin could alleviate this brain edema injury is still unclear. In this study, the rat stroke model was induced by a 1-h left transient middle cerebral artery occlusion using an intraluminal filament, followed by 48 h of reperfusion. The effects of rapamycin (250 μg/kg body weight, intraperitoneal; i.p.) on brain edema progression were evaluated. The results showed that rapamycin treatment significantly reduced the infarct volume, the water content of the brain tissue and the Evans blue extravasation through the blood-brain barrier (BBB). Rapamycin treatment could improve histological appearance of the brain tissue, increased the capillary lumen space and maintain the integrity of BBB. Rapamycin also inhibited matrix metalloproteinase 9 (MMP9) and aquaporin 4 (AQP4) expression. These data imply that rapamycin could improve brain edema progression after reperfusion injury through maintaining BBB integrity and inhibiting MMP9 and AQP4 expression. The data of this study provide a new possible approach for improving brain edema after cerebral ischemia reperfusion by administration of rapamycin.

    Topics: Animals; Aquaporin 4; Blood-Brain Barrier; Brain; Brain Edema; Brain Ischemia; Cerebrovascular Circulation; Male; Matrix Metalloproteinase 9; Permeability; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2014
Autophagy activation contributes to the neuroprotection of remote ischemic perconditioning against focal cerebral ischemia in rats.
    Neurochemical research, 2014, Volume: 39, Issue:11

    Remote ischemic perconditioning (RIPer) has been proved to provide potent cardioprotection. However, there are few studies on neuroprotection of RIPer. This study aims to clarify the neuroprotective effect of RIPer and the role of autophagy induced by RIPer against cerebral ischemia reperfusion injury in rats. Using a transient middle cerebral artery occlusion (MCAO) model in rats to imitate focal cerebral ischemia. RIPer was carried out 4 cycles of 10 min ischemia and 10 min reperfusion, with a thin elastic band tourniquet encircled on the bilateral femoral arteries at the start of 10 min after MCAO. Autophagy inhibitor 3-methyladenine (3-MA) and autophagy inducer rapamycin were administered respectively to determine the contribution of autophagy in RIPer. Neurologic deficit scores, infarct volume, brain edema, Nissl staining, TUNEL assay, immunohistochemistry and western blot was performed to analyze the neuroprotection of RIPer and the contribution of autophagy in RIPer. RIPer significantly exerted neuroprotective effects against cerebral ischemia reperfusion injury in rats, and the autophagy-lysosome pathway was activated by RIPer treatment. 3-MA reversed the neuroprotective effects induced by RIPer, whereas rapamycin ameliorated the brain ischemic injury. Autophagy activation contributes to the neuroprotection by RIPer against focal cerebral ischemia in rats.

    Topics: Adenine; Animals; Autophagy; Brain Ischemia; Cerebral Infarction; Ischemic Postconditioning; Ischemic Preconditioning; Male; Models, Animal; Neuroprotective Agents; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus

2014
Ulinastatin protects cardiomyocytes against ischemia‑reperfusion injury by regulating autophagy through mTOR activation.
    Molecular medicine reports, 2014, Volume: 10, Issue:4

    Autophagy is significant in myocardial ischemia-reperfusion (IR) injury. Ulinastatin has been demonstrated to protect cardiomyocytes against IR through inducing anti-inflammatory effects. However, whether ulinastatin has an anti‑autophagic effect is yet to be elucidated. The present study aimed to investigate the effect of ulinastatin on the regulation of autophagy during IR injury. Cardiomyocytes of neonatal rats were randomly divided into control, hypoxia-reoxygenation (HR) and ulinastatin groups. In order to investigate whether mammalian target of rapamycin (mTOR) is involved in mediating the protective effect of ulinastatin, cells were treated with the mTOR inhibitor, rapamycin 30 min prior to ulinastatin treatment. To demonstrate the anti-autophagic effect of ulinastatin in vivo, a rat IR model was established. Ulinastatin (1x104 U/kg body weight) was administered 30 min prior to the induction of IR via peritoneal injection. Light chain 3 (LC3), phosphorylated (p)‑mTOR, p‑protein kinase B (Akt) and p‑P70S6 kinase (p‑P70S6K) protein expression were assessed using western blot analysis. In addition, cell vitality, myocardial infarct size and lactate dehydrogenase (LDH) levels were measured. LC3‑Ⅱ protein expression was found to be downregulated, while p‑Akt, p‑mTOR and p‑P70S6K protein expression were observed to be upregulated by ulinastatin. In addition, cell vitality was found to increase and LDH was observed to decrease in the ulinastatin group compared with the HR group in vitro. Furthermore, rapamycin was found to attenuate the myocardial protective effect that is induced by ulinastatin. In vivo, ulinastatin was found to downregulate LC3‑Ⅱ protein expression, and reduce myocardium infarct size and LDH serum levels. These findings indicate that ulinastatin exhibits a myocardial protective effect against IR injury by regulating autophagy through mTOR activation.

    Topics: Animals; Autophagy; Cells, Cultured; Disease Models, Animal; Down-Regulation; Glycoproteins; Male; Microtubule-Associated Proteins; Myocytes, Cardiac; Phosphorylation; Protective Agents; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; TOR Serine-Threonine Kinases; Up-Regulation

2014
Rapamycin protects kidney against ischemia reperfusion injury through recruitment of NKT cells.
    Journal of translational medicine, 2014, Aug-19, Volume: 12

    NKT cells play a protective role in ischemia reperfusion (IR) injury, of which the trafficking in the body and recruitment in injured organs can be influenced by immunosuppressive therapy. Therefore, we investigated the effects of rapamycin on kidneys exposed to IR injury in early stage and on trafficking of NKT cells in a murine model.. Balb/c mice were subjected to kidney 30 min ischemia followed by 24 h reperfusion. Rapamycin (2.5 ml/kg) was administered by gavage daily, starting 1 day before the operation. Renal function and histological changes were assessed. The proportion of NKT cells in peripheral blood, spleen and kidney was detected by flow cytometry. The chemokines and corresponding receptor involved in NKT cell trafficking were determined by RT-PCR and flow cytometry respectively.. Rapamycin significantly improved renal function and ameliorated histological injury. In rapamycin-treated group, the proportion of NKT cells in spleen was significantly decreased but increased in peripheral blood and kidney. In addition, the CXCR3+ NKT cell in the kidney increased remarkably in the rapamycin-treated group. The chemokines, CXCL9 and CXCL10, as the ligands of CXCR3, were also increased in the rapamycin-treated kidney.. Rapamycin may recruit NKT cells from spleen to the IR-induced kidney to ameliorate renal IR injury in the early stage.

    Topics: Animals; Apoptosis; Chemotaxis, Leukocyte; Cytoprotection; Ischemia; Kidney; Kidney Function Tests; Killer Cells, Natural; Male; Mice; Mice, Inbred BALB C; Reperfusion Injury; Sirolimus

2014
Effects of everolimus on oxidative stress in kidney model of ischemia/reperfusion injury.
    American journal of nephrology, 2013, Volume: 37, Issue:4

    Reactive oxygen species play an important role in the pathogenesis of kidney ischemia/reperfusion injury (IRI) which may be influenced by immunosuppressive therapy. Pertinent to this, we investigated the effects of the mTOR inhibitor everolimus on redox settings and the activity of the anti-oxidative system in kidneys exposed to IRI.. C57BL/6 mice were subjected to IRI by clamping both renal pedicles for 45 min. Everolimus was applied in daily, subcutaneous doses (0.25 mg/kg body weight), starting 1 day before IRI induction. Both everolimus-treated and non-treated mice were sacrificed at several time points, starting 30 min and finishing 7 days after IRI induction. Markers of oxidation such as glutathione and NADPH levels and anti-oxidative enzyme activities were determined in the kidneys.. In comparison to both sham and non-treated animals, the treatment with everolimus resulted in an increased level of markers of oxidation, including a lower level of glutathione, increased level of oxidized glutathione and reduced level of NADPH. The activity of superoxide dismutase was reduced in both experimental groups, but the effects were less pronounced in everolimus-treated animals. In the early phase of reperfusion, everolimus-treated animals showed higher activity of glutathione reductase in comparison to non-treated animals, whereas the activities of glutathione peroxidase and catalase were generally similar. The treatment with everolimus significantly reduced heme oxygenase-1 expression and increased iNOS mRNA expression when compared to non-treated animals.. Our data imply that everolimus treatment may decrease cytoprotective capacity in kidneys exposed to IRI due to promoted oxidative/nitrosative stress.

    Topics: Animals; Catalase; Everolimus; Glutathione; Glutathione Disulfide; Glutathione Peroxidase; Immunosuppressive Agents; Kidney; Mice; Mice, Inbred C57BL; NADP; Oxidative Stress; Reperfusion Injury; Sirolimus; Superoxide Dismutase

2013
Ischemia preconditioning is neuroprotective in a rat cerebral ischemic injury model through autophagy activation and apoptosis inhibition.
    Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas, 2013, Volume: 46, Issue:7

    Sublethal ischemic preconditioning (IPC) is a powerful inducer of ischemic brain tolerance. However, its underlying mechanisms are still not well understood. In this study, we chose four different IPC paradigms, namely 5 min (5 min duration), 5×5 min (5 min duration, 2 episodes, 15-min interval), 5×5×5 min (5 min duration, 3 episodes, 15-min intervals), and 15 min (15 min duration), and demonstrated that three episodes of 5 min IPC activated autophagy to the greatest extent 24 h after IPC, as evidenced by Beclin expression and LC3-I/II conversion. Autophagic activation was mediated by the tuberous sclerosis type 1 (TSC1)-mTor signal pathway as IPC increased TSC1 but decreased mTor phosphorylation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and hematoxylin and eosin staining confirmed that IPC protected against cerebral ischemic/reperfusion (I/R) injury. Critically, 3-methyladenine, an inhibitor of autophagy, abolished the neuroprotection of IPC and, by contrast, rapamycin, an autophagy inducer, potentiated it. Cleaved caspase-3 expression, neurological scores, and infarct volume in different groups further confirmed the protection of IPC against I/R injury. Taken together, our data indicate that autophagy activation might underlie the protection of IPC against ischemic injury by inhibiting apoptosis.

    Topics: Adenine; Animals; Apoptosis; Autophagy; Brain Ischemia; Caspase 3; Cerebrum; Immunosuppressive Agents; In Situ Nick-End Labeling; Ischemic Preconditioning; Male; Nerve Degeneration; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 1 Protein; Tumor Suppressor Proteins

2013
Protective effect of autophagy inhibition on ischemia-reperfusion-induced injury of N2a cells.
    Journal of Huazhong University of Science and Technology. Medical sciences = Hua zhong ke ji da xue xue bao. Yi xue Ying De wen ban = Huazhong keji daxue xuebao. Yixue Yingdewen ban, 2013, Volume: 33, Issue:6

    Autophagy is a conserved and programmed catabolic process that degrades damaged proteins and organelles. But the underlying mechanism and functions of autophagy in the ischemia-reperfusion (IR)-induced injury are unknown. In this study, we employed simulated IR of N2a cells as an in vitro model of IR injury to the neurons and monitored autophagic processes. It was found that the levels of Beclin-1 (a key molecule of autophay complex, Beclin-1/class III PI3K) and LC-3II (an autophagy marker) were remarkably increased with time during the process of ischemia and the process of reperfusion after 90 min of ischemia, while the protein kinases p70S6K and mTOR which are involved in autophagy regulation showed delayed inactivation after reperfusion. Administration of 3-methyladenine (3MA), an inhibitor of class III PI3K, abolished autophagy during reperfusion, while employment of rapamycin, an inhibitor of mTORC1 (normally inducing autophagy), surprisingly weakened the induction of autophagy during reperfusion. Analyses of mitochondria function by relative cell viability demonstrated that autophagy inhibition by 3-MA attenuated the decline of mitochondria function during reperfusion. Our data demonstrated that there were two distinct dynamic patterns of autophagy during IR-induced N2a injury, Beclin-1/class III PI3K complex-dependent and mTORC1-dependent. Inhibition of over-autophagy improved cell survival. These suggest that targeting autophagy therapy will be a novel strategy to control IR-induced neuronal damage.

    Topics: Adenine; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Cell Line, Tumor; Cell Survival; Mechanistic Target of Rapamycin Complex 1; Mice; Mitochondria; Multiprotein Complexes; Neurons; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Reperfusion Injury; Sirolimus; TOR Serine-Threonine Kinases

2013
Preconditioning donor with a combination of tacrolimus and rapamacyn to decrease ischaemia-reperfusion injury in a rat syngenic kidney transplantation model.
    Clinical and experimental immunology, 2012, Volume: 167, Issue:1

    Reperfusion injury remains one of the major problems in transplantation. Repair from ischaemic acute renal failure (ARF) involves stimulation of tubular epithelial cell proliferation. The aim of this exploratory study was to evaluate the effects of preconditioning donor animals with rapamycin and tacrolimus to prevent ischaemia-reperfusion (I/R) injury. Twelve hours before nephrectomy, the donor animals received immunosuppressive drugs. The animals were divided into four groups, as follows: group 1 control: no treatment; group 2: rapamycin (2 mg/kg); group 3 FK506 (0, 3 mg/kg); and group 4: FK506 (0, 3 mg/kg) plus rapamycin (2 mg/kg). The left kidney was removed and after 3 h of cold ischaemia, the graft was transplanted. Twenty-four hours after transplant, the kidney was recovered for histological analysis and cytokine expression. Preconditioning treatment with rapamycin or tacrolimus significantly reduced blood urea nitrogen and creatinine compared with control [blood urea nitrogen (BUN): P < 0·001 versus control and creatinine: P < 0·001 versus control]. A further decrease was observed when rapamycin was combined with tacrolimus. Acute tubular necrosis was decreased significantly in donors treated with immunosuppressants compared with the control group (P < 0·001 versus control). Moreover, the number of apoptotic nuclei in the control group was higher compared with the treated groups (P < 0·001 versus control). Surprisingly, only rapamycin preconditioning treatment increased anti-apoptotic Bcl2 levels (P < 0·001). Finally, inflammatory cytokines, such as tumour necrosis factor (TNF)-α and interleukin (IL)-6, showed lower levels in the graft of those animals that had been pretreated with rapamycin or tacrolimus. This exploratory study demonstrates that preconditioning donor animals with rapamycin or tacrolimus improves clinical outcomes and reduce necrosis and apoptosis in kidney I/R injury.

    Topics: Animals; Apoptosis; Blood Urea Nitrogen; Complement C3; Creatinine; Cytokines; Drug Evaluation; Drug Synergism; Drug Therapy, Combination; Immunosuppressive Agents; Kidney Transplantation; Kidney Tubular Necrosis, Acute; Male; Postoperative Complications; Premedication; Proto-Oncogene Proteins c-bcl-2; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Tacrolimus

2012
[Immunosuppression in kidney donors with rapamycin and tacrolimus. Proinflammatory cytokine expression].
    Medicina, 2012, Volume: 72, Issue:1

    The ischemia-reperfusion injury (IRI) remains a major problem in transplantation. The objective of this study was to evaluate the effects of preconditioning a donor group with rapamycin and another donor group with tacrolimus to prevent IRI. Twelve hours before nephrectomy, donor Wistar rats received immunosuppressive drugs. The sample was divided into four experimental groups: a sham group, an untreated control group, a group treated with rapamycin (2 mg/kg) and a group treated with tacrolimus (0.3 mg/kg). Left kidneys were removed and, after three hours of cold ischemia, grafts were transplanted. Twenty-four hours later, the transplanted organs were recovered for histological analysis and evaluation of cytokine expression. The pre-conditioning treatment with rapamycin or tacrolimus significantly reduced donor blood urea nitrogen and creatinine levels compared with control group (BUN: p < 0.001 vs. control and creatinine: p < 0.001 vs. control). Acute tubular necrosis was significantly lower in donors treated with immunosuppressant drugs compared with the control group (p < 0.001). Finally, inflammatory cytokines such as TNF-a, IL-6 and rIL-21 showed lower levels in the graft of pre-treated animals. This exploratory experimental study shows that preconditioning donors with rapamycin and tacrolimus in different groups improves clinical outcome and pathology in recipients and reduces in situ pro-inflammatory cytokines associated with Th17 differentiation, creating a favorable environment for the differentiation of regulatory T cells (Tregs).

    Topics: Animals; Cytokines; Disease Models, Animal; Immunosuppression Therapy; Immunosuppressive Agents; Inflammation; Inflammation Mediators; Kidney Transplantation; Living Donors; Male; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Tacrolimus; Transplantation Conditioning; Tumor Necrosis Factor-alpha

2012
Rapamycin induces heme oxygenase-1 in liver but inhibits bile flow recovery after ischemia.
    The Journal of surgical research, 2012, Volume: 176, Issue:2

    Rapamycin, which is employed in the management of patients undergoing liver surgery, induces the synthesis of heme oxygenase-1 (HO-1) in some non-liver cell types. The aim was to investigate whether rapamycin can induce HO-1 expression in the liver, and to test the effects of rapamycin on liver function in the early phase of ischemia reperfusion (IR) injury.. Isolated rat hepatocytes and a rat model of segmental hepatic ischemia and reperfusion were employed. Bile flow was measured gravimetrically or by using indocyanine green. mRNA and protein (by quantitative PCR and Western blot, respectively) and blood concentrations of rapamycin, bilirubin, and liver marker enzymes were measured.. In isolated hepatocytes, rapamycin induced a 6-fold increase in HO-1, comparable to that induced by cobalt proporphyrin (CoPP), and a 2-fold increase in peroxiredoxin-1. Pretreatment of rats with rapamycin resulted in a small increase in liver HO-1 expression, a 20% inhibition of the basal rate of bile flow, and a 50% inhibition in the rate of bile flow recovery after ischemia. CoPP increased basal bile flow by 20% and inhibited bile flow recovery by 50%. These effects were associated with small increases in the blood concentrations of bilirubin and liver marker enzymes.. Rapamycin, through HO-1 induction, has the potential to protect the liver against damage in the late phase of IR. The inhibition by rapamycin of bile flow indicates that its actions on liver function in the acute phase of IR injury are complex.

    Topics: Animals; Anti-Bacterial Agents; Bile; Bilirubin; Disease Models, Animal; Female; Gene Expression Regulation, Enzymologic; Heme Oxygenase-1; Hepatocytes; Liver; Liver Transplantation; Male; Primary Cell Culture; Protoporphyrins; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus

2012
Calcium/calmodulin-dependent protein kinase IV limits organ damage in hepatic ischemia-reperfusion injury through induction of autophagy.
    American journal of physiology. Gastrointestinal and liver physiology, 2012, Jul-15, Volume: 303, Issue:2

    Sterile inflammatory insults, such as ischemia-reperfusion (I/R) injury, result from pathogenic factors, including damage-associated molecular pattern signaling, activation of innate immunity, and upregulation of proinflammatory cytokines. At the same time, a number of protective, or prosurvival, pathways are also activated, and the extent of end-organ damage is ultimately determined by the balance between these two systems. In liver I/R, members of the calcium/calmodulin-dependent protein kinase (CaMK) family are known to be activated, but their individual roles are largely unknown. In this study, we show that one CaMK member, CaMKIV, is protective in hepatic I/R by activating the prosurvival pathway of autophagy in hepatocytes. CaMKIV knockout mice experience significantly worse organ damage after I/R and are deficient in hepatocyte autophagic signaling. Restoration of autophagic signaling with rapamycin reduces organ damage in CaMKIV knockout mice to wild-type levels. In vitro, we show that CaMKIV activation induces autophagy in mouse hepatocytes, and that CaMKIV activation protects hepatocytes from oxidative stress-induced cell death. In conclusion, the protective autophagic signaling pathway serves to reduce organ damage following I/R and is regulated by activation of CaMKIV signaling in hepatocytes.

    Topics: Animals; Autophagy; Calcium-Calmodulin-Dependent Protein Kinase Type 4; Cells, Cultured; Hepatocytes; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxidative Stress; Reperfusion Injury; Signal Transduction; Sirolimus

2012
Ischemic postconditioning during reperfusion attenuates intestinal injury and mucosal cell apoptosis by inhibiting JAK/STAT signaling activation.
    Shock (Augusta, Ga.), 2012, Volume: 38, Issue:4

    The present study attempts to evaluate the role of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling in intestinal ischemia/reperfusion (I/R)-induced intestinal injury and whether immediate ischemic postconditioning ameliorates intestinal injury via attenuation of intestinal mucosal apoptosis subsequent to inhibiting JAK/STAT signaling activation. Anesthetized adult male Sprague-Dawley rats were subjected to superior mesenteric artery occlusion consisting of 60 min of ischemia and 2 h of reperfusion; sham laparotomy served as controls. Animals received either subcutaneous administration of JAK2 inhibitor (AG490, 8 mg/kg) or STAT inhibitor (rapamycin, 0.4 mg/kg) 30 min before ischemia. Ischemic postconditioning was performed by three cycles of 30-s reperfusion and 30-s ischemia initiated immediately upon reperfusion. It was found that intestinal I/R resulted in conspicuous intestinal injury evidenced by significant increases in Chiu's score, lactic acid, and diamine oxidase activity, accompanied with increases in plasma levels of 15-F2t-isoprostane, endothelin 1, and thromboxane B2, as well as increase in the intestinal tissue myeloperoxidase activity. Meanwhile, the apoptotic index and cleaved caspase 3, phosphorylated JAK2, phosphorylated STAT1, and phosphorylated STAT3 expression were significantly enhanced versus sham control. Both ischemic postconditioning and pretreatment with AG490 or rapamycin significantly attenuated all the above changes. These results indicate that JAK/STAT pathway activation plays a critical role in I/R-induced intestinal injury, which is associated with increased oxidative stress, neutrophil accumulation, intestinal mucosal apoptosis, and microcirculation disturbance. Ischemic postconditioning mediates attenuation of intestinal I/R injury, and cell apoptosis may be attributable to the JAK/STAT signaling inhibition.

    Topics: Amine Oxidase (Copper-Containing); Animals; Apoptosis; Caspase 3; Dinoprost; Endothelin-1; Enzyme Activation; Enzyme Inhibitors; Immunosuppressive Agents; Intestinal Mucosa; Ischemic Preconditioning; Janus Kinase 2; Lactic Acid; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; STAT3 Transcription Factor; Thromboxane B2; Tyrphostins

2012
Protective role of p70S6K in intestinal ischemia/reperfusion injury in mice.
    PloS one, 2012, Volume: 7, Issue:7

    The mTOR signaling pathway plays a crucial role in the regulation of cell growth, proliferation, survival and in directing immune responses. As the intestinal epithelium displays rapid cell growth and differentiation and is an important immune regulatory organ, we hypothesized that mTOR may play an important role in the protection against intestinal ischemia reperfusion (I/R)-induced injury. To better understand the molecular mechanisms by which the mTOR pathway is altered by intestinal I/R, p70S6K, the major effector of the mTOR pathway, was investigated along with the effects of rapamycin, a specific inhibitor of mTOR and an immunosuppressant agent used clinically in transplant patients. In vitro experiments using an intestinal epithelial cell line and hypoxia/reoxygenation demonstrated that overexpression of p70S6K promoted cell growth and migration, and decreased cell apoptosis. Inhibition of p70S6K by rapamycin reversed these protective effects. In a mouse model of gut I/R, an increase of p70S6K activity was found by 5 min and remained elevated after 6 h of reperfusion. Inhibition of p70S6K by rapamycin worsened gut injury, promoted inflammation, and enhanced intestinal permeability. Importantly, rapamycin treated animals had a significantly increased mortality. These novel results demonstrate a key role of p70S6K in protection against I/R injury in the intestine and suggest a potential danger in using mTOR inhibitors in patients at risk for gut hypoperfusion.

    Topics: Animals; Apoptosis; Cell Line; Epithelial Cells; Immunosuppressive Agents; Intestinal Diseases; Intestinal Mucosa; Male; Mice; Rats; Reperfusion Injury; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases

2012
Autophagy in proximal tubules protects against acute kidney injury.
    Kidney international, 2012, Volume: 82, Issue:12

    Autophagy is induced in renal tubular cells during acute kidney injury; however, whether this is protective or injurious remains controversial. We address this question by pharmacologic and genetic blockade of autophagy using mouse models of cisplatin- and ischemia-reperfusion-induced acute kidney injury. Chloroquine, a pharmacological inhibitor of autophagy, blocked autophagic flux and enhanced acute kidney injury in both models. Rapamycin, however, activated autophagy and protected against cisplatin-induced acute kidney injury. We also established a renal proximal tubule-specific autophagy-related gene 7-knockout mouse model shown to be defective in both basal and cisplatin-induced autophagy in kidneys. Compared with wild-type littermates, these knockout mice were markedly more sensitive to cisplatin-induced acute kidney injury as indicated by renal functional loss, tissue damage, and apoptosis. Mechanistically, these knockout mice had heightened activation of p53 and c-Jun N terminal kinase, the signaling pathways contributing to cisplatin acute kidney injury. Proximal tubular cells isolated from the knockout mice were more sensitive to cisplatin-induced apoptosis than cells from wild-type mice. In addition, the knockout mice were more sensitive to renal ischemia-reperfusion injury than their wild-type littermates. Thus, our results establish a renoprotective role of tubular cell autophagy in acute kidney injury where it may interfere with cell killing mechanisms.

    Topics: Acute Kidney Injury; Animals; Apoptosis; Autophagy; Autophagy-Related Protein 7; Biomarkers; Blood Urea Nitrogen; Cells, Cultured; Chloroquine; Cisplatin; Creatinine; Cytoprotection; Disease Models, Animal; Enzyme Activation; JNK Mitogen-Activated Protein Kinases; Kidney Tubules, Proximal; Mice; Mice, Inbred C57BL; Mice, Knockout; Microtubule-Associated Proteins; Reperfusion Injury; Signal Transduction; Sirolimus; Time Factors; Tumor Suppressor Protein p53

2012
Rapamycin preconditioning attenuates transient focal cerebral ischemia/reperfusion injury in mice.
    The International journal of neuroscience, 2012, Volume: 122, Issue:12

    Rapamycin, an mTOR inhibitor and immunosuppressive agent in clinic, has protective effects on traumatic brain injury and neurodegenerative diseases. But, its effects on transient focal ischemia/reperfusion disease are not very clear. In this study, we examined the effects of rapamycin preconditioning on mice treated with middle cerebral artery occlusion/reperfusion operation (MCAO/R). We found that the rapamycin preconditioning by intrahippocampal injection 20 hr before MCAO/R significantly improved the survival rate and longevity of mice. It also decreased the neurological deficit score, infracted areas and brain edema. In addition, rapamycin preconditioning decreased the production of NF-κB, TNF-α, and Bax, but not Bcl-2, an antiapoptotic protein in the ischemic area. From these results, we may conclude that rapamycin preconditioning attenuate transient focal cerebral ischemia/reperfusion injury and inhibits apoptosis induced by MCAO/R in mice.

    Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Brain Edema; Brain Infarction; Disease Models, Animal; Female; Gene Expression Regulation; Hippocampus; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred BALB C; Nervous System Diseases; Neurologic Examination; NF-kappa B; Reperfusion Injury; Sirolimus; Survival Rate; Tumor Necrosis Factor-alpha

2012
Protective effect of immunosuppressive treatment before orthotopic kidney autotransplantation.
    Transplant immunology, 2011, Jan-15, Volume: 24, Issue:2

    Ischemia reperfusion injury (IRI) is one of the risk factors for delayed graft function, acute rejection and long term allograft survival after kidney transplantation. IRI is an independent antigen inflammatory process that produces tissue damage. Our objective was to study the impact of immunosuppressive treatment (IS) on IRI applying only one dose of IS before orthotopic kidney autotransplantation.. Twenty-four rats allocated in four groups were studied. One group served as control (G1: autotransplanted rats without IS) and the rest received IS 12 h before kidney autotransplantation (G2: Rapamycin, G3: Mycophenolate mofetil and G4: Tacrolimus).. Improved renal function and systemic inflammatory response were found among IS groups compared to the control group (Delta Urea p<0.0001; Delta Creatinine p<0.0001; Delta C3 p<0.001). The number of apoptotic nuclei in renal medulla in G1 was higher than in IS groups (p<0.0001). Tubular damage was less severe in IS groups respecting G1 (p<0.001). C3, TNF-α and IL-6 expression in kidney samples was reduced when IS was used compared to the control group. No differences were observed among the different immunosuppressive drugs tested. However, Heme oxygenase-1(HO-1) was increased only in Rapamycin treatment.. These data suggest that the use of IS administered before transplant attenuates the IRI process after kidney transplantation in an animal model.

    Topics: Animals; Apoptosis; Complement C3; Creatinine; Graft Survival; Heme Oxygenase-1; Immunosuppressive Agents; Interleukin-6; Kidney Function Tests; Kidney Transplantation; Kidney Tubules; Male; Mycophenolic Acid; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Tacrolimus; Transplantation, Autologous; Urea

2011
Donor pre-treatment with everolimus or cyclosporine does not reduce ischaemia-reperfusion injury in a rat kidney transplant model.
    Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 2011, Volume: 26, Issue:6

    Immunosuppressive agents have been investigated in renal ischaemia-reperfusion injury (IRI) and have frequently demonstrated a beneficial effect. Most studies focused on treatment of the recipient at the time of transplantation. Pre-treatment of these organs before injury (pharmacological pre-conditioning) may particularly protect these organs. This study aimed to investigate the possible protective effects of donor pre-treatment with cyclosporine (CsA) or the mTOR inhibitor everolimus or their combination against IRI during renal transplantation in a rat model.. Donors received vehicle, CsA (5 mg/kg), everolimus (0.5 mg/kg) or CsA + everolimus. Two oral doses were administered to the donors at 24 h and again at 6 h prior to donor kidney removal. Syngeneic rat kidneys were preserved in UW solution for 24 h prior to transplantation. After 24 h of reperfusion, blood and tissue samples were collected from recipients for further analysis.. Renal functions as determined by creatinine and necrosis scores were not different between the experimental groups. Cleaved caspase-3, heat shock protein 70 (HSP70), tumor-necrosis factor-alpha (TNF-α) and nitrotyrosine protein levels were not statistically different between the four treatment groups at 24 h post-transplantation. Blood NMR analysis on metabolic markers for IRI reveals no beneficial effects of donor pre-treatment on the 24-h outcome in transplantation.. When given alone or as a combination to donors before organ recovery, cyclosporine or everolimus does not appear to ameliorate IRI.

    Topics: Animals; Cyclosporine; Everolimus; Graft Rejection; Immunosuppressive Agents; Kidney Function Tests; Kidney Transplantation; Male; Rats; Rats, Inbred Lew; Reperfusion Injury; Sirolimus; Tissue Donors; Transplantation Conditioning; Treatment Outcome

2011
Mechanisms mediating the cardioprotective effects of rapamycin in ischaemia-reperfusion injury.
    Clinical and experimental pharmacology & physiology, 2011, Volume: 38, Issue:1

    1. In the present study, the temporal and concentration-dependent cardioprotective effects of rapamycin against ischaemia-reperfusion (I/R) injury, as well as the underlying mechanisms, were investigated. 2. Rat Langendorff-perfused isolated hearts were exposed to 40 min global ischaemia followed by 120 min reperfusion. Hearts were perfused with different concentrations of rapamycin before and after ischaemia. Myocardial injury was assessed in terms of infarct size and the release of lactate dehydrogenase (LDH) and creatine kinase (CK). The phosphorylation of Akt, extracellular signal-regulated kinase (ERK) 1/2 and endothelial nitric oxide synthase (eNOS) was determined at the end of reperfusion. 3. When administered prior to ischaemia, 25, 50 and 100 nmol/L rapamycin significantly reduced infarct size compared with control (40.1 ± 1.5, 26.3 ± 4.1 and 21.2 ± 3.4 vs 52.5 ± 4.5%, respectively) without affecting the recovery of ventricular function. No reduction in infarct size was observed when 50 nmol/L rapamycin was administered 10 or 120 min into the reperfusion period. 4. Rapamycin (50 nmol/L) enhanced the phosphorylation of Akt kinase but did not affect the phosphorylation of ERK1/2 or eNOS at the end of reperfusion. The cardioprotective effect of rapamycin was blocked by the phosphatidylinositol 3-kinase (Akt) inhibitor LY294002 (15 nmol/L). 5. In conclusion, rapamycin mediates cardioprotection prior to ischaemia and after reperfusion. This protection may involve activation of the phosphatidylinositol 3-kinase pathway.

    Topics: Algorithms; Animals; Cardiotonic Agents; Creatine Kinase; Drug Evaluation, Preclinical; Hemodynamics; In Vitro Techniques; L-Lactate Dehydrogenase; Male; Myocardial Infarction; Organ Size; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Signal Transduction; Sirolimus

2011
Sirolimus prevents short-term renal changes induced by ischemia-reperfusion injury in rats.
    American journal of nephrology, 2011, Volume: 33, Issue:3

    Ischemia-reperfusion (I/R) is present at various degrees in kidney transplants. I/R plays a major role in early function and long-term survival of renal allograft. The purpose of our study was to determine if immunosuppressants modulate I/R in a model that separates I/R from all immune responses.. Sprague-Dawley rats with monolateral renal I/R received daily cyclosporine (A), tacrolimus (B), sirolimus (C) or saline (D). Sham-operated rats received saline (E). After 30 days, glomerular filtration rate for each kidney was measured by inulin clearance. Kidney injury was examined, and TGF-β, fibronectin and metalloproteases were evaluated by real-time PCR, Western blot and zymography.. Sirolimus, but not cyclosporine and tacrolimus, prevented a glomerular filtration rate decrease in I/R kidneys (403 ± 303 vs. 1,006 ± 484 μl/min, p < 0.05; 126 ± 170 vs. 567 ± 374 μl/min, p < 0.05; 633 ± 293 vs. 786 ± 255; A, B and C group, respectively, I/R vs. contralateral kidneys). Sirolimus reduced ED-1+ cell infiltrate, interstitial fibrosis and intimal thickening of small vessels observed in I/R kidneys of controls and calcineurin inhibitor-treated rats. Tacrolimus and cyclosporine increased fibronectin and TGF-β expression and matrix deposition. Only sirolimus increased metalloprotease activity.. Sirolimus but not calcineurin inhibitors prevented I/R-induced kidney injury.

    Topics: Animals; Cyclosporine; Glomerular Filtration Rate; Immunosuppressive Agents; Kidney; Kidney Diseases; Kidney Function Tests; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Tacrolimus

2011
Rapamycin (sirolimus) protects against hypoxic damage in primary heart cultures via Na+/Ca2+ exchanger activation.
    Life sciences, 2011, Jul-04, Volume: 89, Issue:1-2

    Rapamycin (sirolimus) is an antibiotic that inhibits protein synthesis through mammalian targeting of rapamycin (mTOR) signaling, and is used as an immunosuppressant in the treatment of organ rejection in transplant recipients. Rapamycin confers preconditioning-like protection against ischemic-reperfusion injury in isolated mouse heart cultures. Our aim was to further define the role of rapamycin in intracellular Ca(2+) homeostasis and to investigate the mechanism by which rapamycin protects cardiomyocytes from hypoxic damage.. We demonstrate here that rapamycin protects rat heart cultures from hypoxic-reoxygenation (H/R) damage, as revealed by assays of lactate dehydrogenase (LDH) and creatine kinase (CK) leakage to the medium, by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) measurements, and desmin immunostaining. As a result of hypoxia, intracellular calcium levels ([Ca(2+)](i)) were elevated. However, treatment of heart cultures with rapamycin during hypoxia attenuated the increase of [Ca(2+)](i). Rapamycin also attenuated (45)Ca(2+) uptake into the sarcoplasmic reticulum (SR) of skinned heart cultures in a dose- and time-dependent manner. KB-R7943, which inhibits the "reverse" mode of Na(+)/Ca(2+) exchanger (NCX), protected heart cultures from H/R damage with or without the addition of rapamycin. Rapamycin decreased [Ca(2+)](i) following its elevation by extracellular Ca(2+) ([Ca(2+)](o)) influx, thapsigargin treatment, or depolarization with KCl.. We suggest that rapamycin induces cardioprotection against hypoxic/reoxygenation damage in primary heart cultures by stimulating NCX to extrude Ca(2+) outside the cardiomyocytes.. According to our findings, rapamycin preserves Ca(2+) homeostasis and prevents Ca(2+) overload via extrusion of Ca(2+) surplus outside the sarcolemma, thereby protecting the cells from hypoxic stress.

    Topics: Animals; Calcium; Cell Hypoxia; Cells, Cultured; Creatine Kinase; Dose-Response Relationship, Drug; Homeostasis; L-Lactate Dehydrogenase; Rats; Reperfusion Injury; Sarcoplasmic Reticulum; Sirolimus; Sodium-Calcium Exchanger; Tetrazolium Salts; Thiazoles; Thiourea; Time Factors

2011
Short-term immunossupressive treatment of the donor does not prevent ischemia-reperfusion kidney damage in the rat.
    Transplantation proceedings, 2011, Volume: 43, Issue:9

    Ischemia-reperfusion (IR) kidney damage is an important factor for allograft survival in kidney transplantation. Recently it has been shown that immune factors from donor-derived cells are important in IR injury. The aim of this article was to evaluate the impact of short-term immunosuppressive treatment of the donor over a time frame relevant to cadaveric transplantation on IR damage to the rat kidney.. Male Sprague-Dawley rats served as donors and recipients. Three experimental groups were evaluated according to the donor treatment (n = 6); control (no treatment); sirolimus (1 mg/kg orally) or FTY720 (1 mg/kg intravenously) at 6 or 1 hours prior to left nephrectomy. Kidneys were flushed with cold Euro-Collins solution and after 2 hours transplanted using microsurgical techniques concomittant with a left nephrectomy. After 48 hours (day 0), we removed the right kidney. Serum creatinine (SCr) was determined daily thereafter as well as differential leukocyte counts prior to donor nephrectomy and sirolimus plasma levels thereafter.. No difference was observed in SCr on day 1: control (3.97 ± 0.73 mg/dL), sirolimus (4.02 ± 1.44 mg/dL) and FTY 720 (3.27 ± 1.79 mg/dL; P = NS), or thereafter. Mortality was 50% in each group. Animals receiving FTY 720 showed a significant reduction in lymphocyte count (8.0 ± 3.1 to 1.1 ± 0.3 (P < .01). Sirolimus levels were 9.3 ± 1.5 ng/mL.. We concluded that immunosuppressive treament of the donor within a time frame relevant to cadaveric kidney transplantation did not offer a benefit in terms of preventing IR injury.

    Topics: Animals; Cadaver; Creatinine; Fingolimod Hydrochloride; Graft Survival; Hypertonic Solutions; Immunosuppressive Agents; Kidney Transplantation; Male; Propylene Glycols; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Sphingosine; Tissue Donors

2011
Sirolimus attenuates reduced-size liver ischemia-reperfusion injury but impairs liver regeneration in rats.
    Digestive diseases and sciences, 2010, Volume: 55, Issue:8

    Evidence has suggested that immunosuppressive drugs impact ischemia-reperfusion injury.. The purpose of the present study was to evaluate the effect of sirolimus on hepatic injury and regeneration in a rat reduced-size liver ischemia-reperfusion model.. Using a newly developed rat reduced-size liver ischemia-reperfusion injury model, the effects of sirolimus were evaluated by assessing liver cell apoptosis and aspartate aminotransferase, myeloperoxidase, and malondialdehyde levels. In addition, liver regeneration after sirolimus treatment was evaluated by measuring liver weight resumption and by the histological examination of bromodeoxyuridine and proliferating cell nuclear antigen expression.. Sirolimus significantly decreased liver cell apoptosis as well as tissue myeloperoxidase and malondialdehyde levels, but impaired postischemic liver regeneration. Ischemia-reperfusion-induced elevation of aspartate aminotransferase serum levels was significantly decreased by sirolimus.. Despite an impairment of postischemic liver proliferation, sirolimus demonstrated beneficial amelioration of ischemia-reperfusion-induced liver injury in a reduced-size liver model in rats.

    Topics: Animals; Aspartate Aminotransferases; Cell Proliferation; Hepatocytes; Immunosuppressive Agents; Lipid Peroxidation; Liver; Liver Regeneration; Male; Neutrophil Activation; Neutrophils; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Time Factors

2010
Rapamycin inhibits cholangiocyte regeneration by blocking interleukin-6-induced activation of signal transducer and activator of transcription 3 after liver transplantation.
    Liver transplantation : official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society, 2010, Volume: 16, Issue:2

    Cholangiocyte proliferation is necessary for biliary recovery from cold ischemia and reperfusion injury (CIRI), but there are few studies on its intracellular mechanism. In this process, the role of rapamycin, a new immunosuppressant used in liver transplantation, is still unknown. In order to determine whether rapamycin can depress cholangiocyte regeneration by inhibiting signal transducer and activator of transcription 3 (STAT3) activation, rapamycin (0.05 mg/kg) was administered to rats for 3 days before orthotopic liver transplantation. The results indicated that cholangiocytes responded to extended cold preservation (12 hours) with severe bile duct injures, marked activation of the interleukin-6 (IL-6)/STAT3 signal pathway, and increased expression of cyclin D1 until 7 days after transplantation, and this was followed by compensatory cholangiocyte regeneration. However, rapamycin treatment inhibited STAT3 activation and resulted in decreased cholangiocyte proliferation and delayed biliary recovery after liver transplantation. On the other hand, rapamycin showed no effect on the expression of IL-6. We conclude that the IL-6/STAT3 signal pathway is involved in initiating cholangiocytes to regenerate and repair CIRI. Rapamycin represses cholangiocyte regeneration by inhibiting STAT3 activation, which might have a negative effect on the healing and recovery of bile ducts in grafts with extended cold preservation. Insights gained from this study will be helpful in designing therapy using rapamycin in clinical patients after liver transplantation.

    Topics: Animals; Bile Ducts, Intrahepatic; Cell Division; Cryopreservation; Cyclin D1; Disease Models, Animal; Graft Rejection; Immunosuppressive Agents; Interleukin-6; Liver Regeneration; Liver Transplantation; Male; Phosphorylation; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; STAT3 Transcription Factor

2010
Effects of sirolimus alone or in combination with cyclosporine A on renal ischemia/reperfusion injury.
    Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas, 2010, Volume: 43, Issue:8

    Calcineurin inhibitors exacerbate ischemic injury in transplanted kidneys, but it is not known if sirolimus protects or exacerbates the transplanted kidney from ischemic injury. We determined the effects of sirolimus alone or in combination with cyclosporin A (CsA) on oxygenated and hypoxic/reoxygenated rat proximal tubules in the following in vitro groups containing 6-9 rats per group: sirolimus (10, 50, 100, 250, 500, and 1000 nanog/mL); CsA (100 microg/mL); sirolimus (50 and 250 nanog/mL) + CsA (100 microg/mL); control; vehicle (20% ethanol). For in vivo studies, 3-week-old Wistar rats (150-250 g) were submitted to left nephrectomy and 30-min renal artery clamping. Renal function and histological evaluation were performed 24 h and 7 days after ischemia (I) in five groups: sham, I, I + SRL (3 mg x kg(-1) x day(-1), po), I + CsA (3 mg x kg(-1) x day(-1), sc), I + SRL + CsA. Sirolimus did not injure oxygenated or hypoxic/reoxygenated proximal tubules and did not potentiate the tubular toxic effects of CsA. Neither drug affected the glomerular filtration rate (GFR) at 24 h. GFR was reduced in CsA-treated rats on day 7 (0.5 +/- 0.1 mL/min) but not in rats receiving sirolimus + CsA (0.8 +/- 0.1 mL/min) despite the reduction in renal blood flow (3.9 +/- 0.5 mL/min). Acute tubular necrosis regeneration was similar for all groups. Sirolimus alone was not toxic and did not enhance hypoxia/reoxygenation injury or CsA toxicity to proximal tubules. Despite its hemodynamic effects, sirolimus protected post-ischemic kidneys against CsA toxicity.

    Topics: Animals; Cyclosporine; Drug Therapy, Combination; Glomerular Filtration Rate; Immunosuppressive Agents; Kidney; Kidney Tubules, Proximal; Male; Nephrectomy; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus

2010
Both tacrolimus and sirolimus decrease Th1/Th2 ratio, and increase regulatory T lymphocytes in the liver after ischemia/reperfusion.
    Laboratory investigation; a journal of technical methods and pathology, 2009, Volume: 89, Issue:4

    The protective effects of immunosuppressants against ischemia/reperfusion (I/R) injury have been attributed to their non-specific anti-inflammatory effect. However, these effects may also depend on their effect on T lymphocytes, which are increasingly considered to be key players in I/R. Here, we studied the effects of tacrolimus and sirolimus on lymphocyte subpopulations in an I/R rat model. The animals were treated with tacrolimus, sirolimus or vehicle, before undergoing a 60-min ischemia event of the right hepatic lobe, followed by excision of the remaining liver. After 2 h, I/R rats showed increased mortality, plasma lactate dehydrogenase (LDH) levels, hepatocyte apoptosis, liver histological injury and parenchymal infiltration by neutrophils, macrophages, NK cells and T lymphocytes. Most of the changes were antagonized by both immunosuppressants. Tacrolimus augmented the proportion of cycling cells in I/R rats, whereas sirolimus showed the opposite effect. The increased Th1/Th2 ratio found in I/R livers after 2 h was reverted by immunosuppressants, which also amplified the proportion of CD4(+)CD25(+)Foxp3(+) regulatory T lymphocytes at 24 h. The protective effects of both tacrolimus and sirolimus correlated well with a decreased ratio of proinflammatory to anti-inflammatory T lymphocytes, and with an increase in the Treg proportion. This suggests a new mechanism to explain the known beneficial effect shown by immunosuppressants early after I/R.

    Topics: Animals; Apoptosis; Hepatectomy; Immunosuppressive Agents; Liver; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; T-Lymphocytes, Regulatory; Tacrolimus; Th1 Cells; Th2 Cells

2009
In vitro induced CD4(+)CD25(+)Foxp3(+) Tregs attenuate hepatic ischemia-reperfusion injury.
    International immunopharmacology, 2009, Volume: 9, Issue:5

    Reperfusion injury causes liver dysfunction after warm or cold ischemia. Emerging data suggest a role of T cells as mediators in this ischemia/reperfusion (I/R) injury. In the T cells, a part of CD4(+)CD25(+)FoxP3(+) T regulatory cells (Tregs) were reported to facilitate recovery from I/R injury. These Tregs can be induced by TGF-beta in vitro. Interestingly, rapamycin was reported to selectively expand these Tregs in vitro. In the present study, addition of rapamycin to cultures containing TGF-beta further increased the frequency and absolute number of functional CD4(+) Tregs. Using a partial (70%) hepatic warm ischemia model, we investigated the effects of liver function recovery under the treatment of Tregs induced by rapamycin and TGF-beta. The treatment of Tregs significantly reduced serum alanine aminotransferase and aspartate aminotransferase compared to I/R control animals at 24 h after reperfusion (P<0.05). They also significantly attenuated the up-regulation of IFN-gamma and IL-17 compared to the I/R control animals (P<0.05). In conclusion, Tregs ameliorate the biochemical of hepatic I/R injury by preventing proinflammatory cytokines following a warm I/R insult. These data may pave the way to use Tregs as cell therapy to prevent hepatic I/R injury.

    Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; CD4 Antigens; Forkhead Transcription Factors; Interferon-gamma; Interleukin-17; Interleukin-2 Receptor alpha Subunit; Liver; Lymphocyte Activation; Male; Rats; Rats, Wistar; Recovery of Function; Reperfusion Injury; Sirolimus; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

2009
Effects of everolimus on cytokines, oxidative stress, and renal histology in ischemia-reperfusion injury of the kidney.
    Renal failure, 2009, Volume: 31, Issue:8

    To evaluate the effects of everolimus on renal ischemia-reperfusion injury (IRI).. Wistar albino rats were divided into control, ischemia-reperfusion (IR), and ischemia-reperfusion/everolimus (IR/eve) groups. Everolimus was administered for seven consecutive days to the IR/eve group prior to injury. IR and IR/eve groups underwent forty-five minutes ischemia followed by the application of reperfusion at 2 and 24 hours. Blood samples and kidneys were taken from all animals.. . Serum blood urea nitrogen and creatinine levels increased at two hours of reperfusion in the IR and IR/eve groups, and decreased at 24 hours of reperfusion in the IR group. In the IR/eve group, we detected significantly high interleukin-6 levels and low tumor necrosis factor-alpha and malondialdehyde levels at 24 hours. Myeloperoxidase levels increased at two hours of reperfusion in the IR/eve group, but decreased significantly at 24 hours. Everolimus did not improve renal tubular and interstitial injuries in renal IRI.. It has been demonstrated that pretreatment with everolimus has beneficial effects on cytokines and oxidative stress in renal IRI. However, these effects are insufficient for the correction of histopathological changes and restoration of normal kidney function.

    Topics: Animals; Cytokines; Everolimus; Immunosuppressive Agents; Kidney; Kidney Diseases; Oxidative Stress; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus

2009
Blockade of Hsp20 phosphorylation exacerbates cardiac ischemia/reperfusion injury by suppressed autophagy and increased cell death.
    Circulation research, 2009, Dec-04, Volume: 105, Issue:12

    The levels of a small heat shock protein (Hsp)20 and its phosphorylation are increased on ischemic insults, and overexpression of Hsp20 protects the heart against ischemia/reperfusion injury. However, the mechanism underlying cardioprotection of Hsp20 and especially the role of its phosphorylation in regulating ischemia/reperfusion-induced autophagy, apoptosis, and necrosis remain to be clarified.. Herein, we generated a cardiac-specific overexpression model, carrying nonphosphorylatable Hsp20, where serine 16 was substituted with alanine (Hsp20(S16A)). By subjecting this model to ischemia/reperfusion, we addressed whether: (1) the cardioprotective effects of Hsp20 are associated with serine 16 phosphorylation; (2) blockade of Hsp20 phosphorylation influences the balance between autophagy and cell death; and (3) the aggregation pattern of Hsp20 is altered by its phosphorylation.. Our results demonstrated that Hsp20(S16A) hearts were more sensitive to ischemia/reperfusion injury, evidenced by lower recovery of contractile function and increased necrosis and apoptosis, compared with non-TG hearts. Interestingly, autophagy was activated in non-TG hearts but significantly inhibited in Hsp20(S16A) hearts following ischemia/reperfusion. Accordingly, pretreatment of Hsp20(S16A) hearts with rapamycin, an activator of autophagy, resulted in improvement of functional recovery, compared with saline-treated Hsp20(S16A) hearts. Furthermore, on ischemia/reperfusion, the oligomerization pattern of Hsp20 appeared to shift to higher aggregates in Hsp20(S16A) hearts.. Collectively, these data indicate that blockade of Ser16-Hsp20 phosphorylation attenuates the cardioprotective effects of Hsp20 against ischemia/reperfusion injury, which may be attributable to suppressed autophagy and increased cell death. Therefore, phosphorylation of Hsp20 at serine 16 may represent a potential therapeutic target in ischemic heart disease.

    Topics: Alanine; Animals; Apoptosis; Autophagy; Base Sequence; Disease Models, Animal; Heart Failure; HSP20 Heat-Shock Proteins; Humans; Male; Mice; Mice, Transgenic; Molecular Sequence Data; Mutation; Myocardial Contraction; Myocardium; Necrosis; Phosphorylation; Recovery of Function; Reperfusion Injury; Serine; Sirolimus; Time Factors; Ventricular Function, Left; Ventricular Pressure

2009
Effects of delayed rapamycin treatment on renal fibrosis and inflammation in experimental ischemia reperfusion injury.
    Transplantation proceedings, 2009, Volume: 41, Issue:10

    Ischemia reperfusion injury (IRI) has long-term sequelae on kidney allograft function. Early initiation of rapamycin can retard surgical wound healing and recovery from IRI. In contrast, rapamycin may paradoxically retard long-term fibrotic effects of kidney IRI. We, therefore, hypothesized that delayed initiation of rapamycin after kidney ischemia, started after the initial week of wound healing, would decrease the long-term inflammation and fibrosis caused by IRI. C57BL/6 male mice were subjected to either 45 or 60 minutes of unilateral kidney ischemia or a sham operation. Mice were given rapamycin (subcutaneous, 1.5 mg/kg/d) or vehicle starting at 1 week after IRI surgery for 3 weeks. Urine albumin excretion, kidney histology, and kidney cytokine proteins were examined at 4 weeks after surgery. The 3-week treatment course of rapamycin significantly reduced body weight gain in all 3 groups and reduced postischemic kidney weight in both the 45- and 60-minute ischemia groups, but unexpectedly increased urine albumin excretion in all rapamycin-treated sham or IRI mice compared with vehicle-treated mice. Rapamycin treatment showed minimal effects on postischemic kidney fibrosis with variable effects on various cytokine/chemokine protein expressions, namely, decreasing interleukin (IL)-1alpha, IL-6, tumor necrosis factor (TNF)-alpha, and regulated on activation normal T cell expressed and secreted (RANTES) while increasing IL-4, keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP-1alpha), and IL-10 in the ischemic kidney. These data demonstrated that rapamycin reduced mouse body weight and ischemic kidney weight, while increasing urinary albumin excretion. Delayed initiation of rapamycin after IRI had a minimal effect on renal fibrosis and mixed effects on proinflammatory mediator production. These data do not support delayed initiation of rapamycin after IRI to attenuate IRI-induced progressive fibrosis and inflammation, and They raise further caution regarding rapamycin and albuminuria.

    Topics: Albuminuria; Animals; Body Weight; Cytokines; Fibrosis; Immunosuppressive Agents; Injections, Subcutaneous; Kidney; Kidney Diseases; Male; Mice; Mice, Inbred C57BL; Organ Size; Reperfusion Injury; Sirolimus; Weight Gain

2009
Sirolimus improves early microcirculation, but impairs regeneration after pancreatic ischemia-reperfusion injury.
    American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons, 2007, Volume: 7, Issue:1

    Ischemia and reperfusion injury remains a relevant problem in clinical pancreas transplantation. We investigated the effect of sirolimus (SRL) in a rodent model of 90-min warm pancreatic ischemia. Four groups were studied: (1) sham surgery and vehicle; (2) sham surgery and SRL; (3) warm ischemia and vehicle; (4) warm ischemia and SRL. SRL (1.5 mg/kg/day) and vehicle were administered intraperitoneally for 3 days prior to surgery until the animals were killed. Microcirculation was assessed immediately after reperfusion by means of intravital fluorescence microscopy. Histopathological injury, apoptosis, proliferation and biochemical parameters were analyzed at 2 h, 1 day and 5 days after surgery. Ninety minutes after ischemia, intravital microscopy revealed an improved functional capillary density (p < 0.05) and reduction of adherent leucocytes (p < 0.01) and platelets (p < 0.05) in the SRL-treated group compared to the vehicle-treated controls. In contrast, on day 5 after ischemia, the pancreatic tissue of SRL-treated animals showed a higher grade of histological injury (p < 0.05) and higher rate of apoptotic cells (p < 0.05) than the vehicle controls. In summary, our data indicate that administration of SRL improves microcirculation at a very early stage, but results in an impairment of the recovery phase after pancreatic ischemia-reperfusion injury.

    Topics: Animals; Apoptosis; Blood Platelets; Cell Adhesion; Cell Proliferation; Hot Temperature; Leukocytes; Male; Microcirculation; Pancreas; Pancreas Transplantation; Rats; Rats, Inbred Lew; Regeneration; Reperfusion Injury; Sirolimus; Splanchnic Circulation; Time Factors

2007
The role of immunosuppressive drugs in aggravating renal ischemia and reperfusion injury.
    Transplantation proceedings, 2007, Volume: 39, Issue:2

    Renal ischemia followed by reperfusion leads to acute renal failure in both native kidneys and renal allografts. Cyclosporine has known nephrotoxic effects. Thus, cyclosporine therapy subsequent to ischemia/reperfusion (I/R) injury may further exacerbate graft dysfunction. Rapamycin is a newer agent that suppresses the immune system by a different mechanism. In the present study, the effects of Cyclosporine and rapamycin at low and higher concentrations were investigated in an I/R-induced injury model.. Cyclosporine (100 mg/kg or 50 mg/kg), rapamycin (3 mg/kg per day or 1.5 mg/kg), or both were administered to mice before being subjected to 45 minutes of ischemia. Blood and kidney samples were collected at 24, 48, and 120 hours after surgery. We quantified acute tubular necrosis and tubular regeneration.. Animals subjected to I/R showed impaired renal function that peaked at 24 hours (2.05 +/- 0.23 mg/dL), decreasing thereafter. Treatment with higher concentrations of cyclosporine or rapamycin caused even more renal dysfunction at 48 hours, which was sustained up to 120 hours after reperfusion (1.53 +/- 0.6 mg/dL), when compared to the low concentrations of cyclosporine or rapamycin (1.08 +/- 0.19 mg/dL; 0.99 +/- 0.14 mg/dL, P < .05, respectively). Cyclosporine delayed tubular regeneration, which was higher in controls at day 5 (67.0% vs 37.6%, P < .05).. These results demonstrated that cyclosporine or rapamycin might further aggravate ischemically injured organs, negatively affecting posttransplantation recovery in a concentration-dependent fashion.

    Topics: Animals; Cyclosporine; Immunosuppressive Agents; Kidney Function Tests; Kidney Transplantation; Male; Mice; Mice, Inbred C57BL; Models, Animal; Postoperative Complications; Reperfusion Injury; Sirolimus; Transplantation, Isogeneic; Treatment Outcome

2007
A role for HO-1 in renal function impairment in animals subjected to ischemic and reperfusion injury and treated with immunosuppressive drugs.
    Transplantation proceedings, 2007, Volume: 39, Issue:2

    Ischemia/reperfusion injury (IRI) represents the single major antigen-independent factor implicated in pathogenesis of chronic graft dysfunction. Tacrolimus is a calcineurin inhibitor, which has been suggested to be helpful in cyclosporine-related chronic toxicity. Rapamycin has antiproliferative properties that may impair renal regeneration after IRI. Therefore, immunosuppressive drugs might impair renal graft outcome in those organs suffering IRI.. C57B1/6 male mice subjected to 45 minutes of renal pedicle ligation were reperfused for 24 hours. Mice were treated with rapamycin, cyclosporine, or tacrolimus. Blood and renal tissue samples were collected at 24 hours after IRI. Urea levels were measured. Heme Oxygenase 1 (HO-1) gene transcript was amplified by a real-time polymerase chain reaction technique.. Animals treated with cyclosporine and subjected to IRI showed impaired renal function that peaked at 24 hours. Additional pretreatment with rapamycin produced even more impairment of renal function, when compared with controls. However, tacrolimus pretreatment was associated with a better renal outcome. HO-1 expression was upregulated after IRI by 2.6 arbitrary units at 24 hours. Rapamycin showed worse impairment of renal function.. Tacrolimus was not associated with worsening renal function when compared with animals just subjected to IRI. Upregulation of HO-1 may be an attractive approach to limit graft injury.

    Topics: Animals; Cyclosporine; Heme Oxygenase-1; Immunosuppressive Agents; Kidney Diseases; Kidney Function Tests; Male; Mice; Mice, Inbred C57BL; Polymerase Chain Reaction; Reperfusion Injury; Sirolimus; Tacrolimus; Transcription, Genetic

2007
Effect of rapamycin on renal ischemia-reperfusion injury in mice.
    Transplant international : official journal of the European Society for Organ Transplantation, 2006, Volume: 19, Issue:10

    The aim of this study was to determine the effect of rapamycin on renal ischemia-reperfusion injury (IRI) in mice. Renal IRI was induced in male BALB/c mice by clamping both renal pedicles for 45 min. The mice were treated with either vehicle or rapamycin (2 mg/kg/day) by oral gavage, starting 1 day before the IRI and continued daily till killing. The mice were killed on days 1, 3 and 7 after the operation. The severity of the renal IRI was assessed by serum creatinine levels and renal histology. Proliferation of renal tubular cells was quantified by immunohistochemical staining for proliferating cell nuclear antigen (PCNA). One day after the IRI, the serum creatinine levels of rapamycin-treated mice were significantly higher than those of the vehicle-treated mice. Kidney sections from rapamycin-treated mice showed more marked tubular damage and significantly lower number of PCNA-positive cells. The number of PCNA-positive cells in the rapamycin-treated mice remained significantly lower on day 3 after the IRI. By day 7 after the IRI, the serum creatinine levels, renal histology and positive PCNA staining in the kidney sections became similar between the two treatment groups. We conclude that in this murine model of renal IRI, rapamycin treatment aggravates renal IRI during the first 3 days after the insult. This effect might be mediated, at least partly, through inhibition of renal tubular cell proliferation.

    Topics: Animals; Cell Proliferation; Creatinine; Immunohistochemistry; Immunosuppressive Agents; Kidney; Kidney Diseases; Kidney Transplantation; Kidney Tubules; Male; Mice; Mice, Inbred BALB C; Reperfusion Injury; Sirolimus

2006
The role of heme oxygenase 1 in rapamycin-induced renal dysfunction after ischemia and reperfusion injury.
    Kidney international, 2006, Volume: 70, Issue:10

    Ischemia and reperfusion injury (IRI) is the main etiology of acute renal failure in native and transplanted kidneys. In the transplantation field, immunosuppressive drugs may play an additional role in acute graft dysfunction. Rapamycin may impair renal regeneration post IRI. Heme oxygenase 1 (HO-1) is a protective gene with anti-inflammatory and anti-apoptotic actions. We investigated whether HO-1 played a role in rapamycin-induced renal dysfunction in an established model of IRI. Rapamycin (3 mg/kg) was administered to mice before being subjected to 45 min of ischemia. Animals subjected to IRI presented with impaired renal function that peaked at 24 h (2.05+/-0.23 mg/dl), decreasing thereafter. Treatment with rapamycin caused even more renal dysfunctions (2.30+/-0.33 mg/dl), sustained up to 120 h after reperfusion (1.54+/-0.4 mg/dl), when compared to the control (0.63+/-0.09 mg/dl, P<0.05). Rapamycin delayed tubular regeneration that was normally higher in the control group at day 5 (68.53+/-2.30 vs 43.63+/-3.11%, P<0.05). HO-1 was markedly upregulated after IRI and its expression was even enhanced by rapamycin (1.32-fold). However, prior induction of HO-1 by cobalt protoporphyrin improved the renal dysfunction imposed by rapamycin, mostly at later time points. These results demonstrated that rapamycin used in ischemic-injured organs could also negatively affect post-transplantation recovery. Modulation of HO-1 expression may represent a feasible approach to limit rapamycin acute toxicity.

    Topics: Acute Kidney Injury; Animals; Gene Expression Regulation, Enzymologic; Heme Oxygenase-1; Immunosuppressive Agents; Kidney; Kidney Transplantation; Male; Mice; Mice, Inbred C57BL; Protoporphyrins; Reperfusion Injury; Sirolimus

2006
Inflammation and caspase activation in long-term renal ischemia/reperfusion injury and immunosuppression in rats.
    Kidney international, 2005, Volume: 68, Issue:5

    We have previously shown the long-term influence of renal ischemia/reperfusion (I/R) injury and immunosuppression on fibrotic genes and apoptosis in a rat model. For the first time, we have now investigated the effects of I/R and immunosuppression on inflammation and caspase activation.. I/R injury was induced in the right kidney and the left was removed. Cyclosporin (CsA) (10 mg/kg), tacrolimus (0.2 mg/kg), rapamycin (1 mg/kg), or mycophenolate mofetil (MMF) (10 mg/kg) was then administered for 16 weeks. The effects of I/R and immunosuppressants on interstitial inflammation, interleukin (IL)-1beta expression, caspase-1 and caspase-3 activation, tubulointerstitial damage, and fibrosis were evaluated.. ED-1+ (a specific rat monocyte/macrophage marker) cells were mainly localized in the tubulointerstitium and periglomerular areas and increased in I/R group compared to controls (P < 0.01). This was further increased by CsA, but decreased by tacrolimus, rapamycin, or MMF (P < 0.05). The 17 kD active IL-1beta remained unchanged, but 35 kD IL-1beta precursor was decreased by rapamycin in comparison with I/R group (P < 0.05). The 45 kD or 20 kD caspase-1 was increased by I/R or CsA, respectively, and decreased by rapamycin (P < 0.05). The 24 kD caspase-3, which proved to be an active caspase-3 subunit, was increased in I/R and CsA groups and deceased by tacrolimus, rapamycin, or MMF (P < 0.05), but not 32 kD precursor or 17 kD active caspase-3. The activity data of caspase-1 and caspase-3 exhibited the same trend as Western blotting data. The staining of active caspase-3 was scattered in kidneys, mainly in tubular and interstitial areas, which was consistent with that of ED-1+ cells. There was a strong positive correlation between interstitial inflammation and 24 kD caspase-3 expression or caspase-3 activity (r = 0.814 or 0.484), all of which were also closely related with urinary protein (r = 0.537, 0.529, or 0.517), serum creatinine (r = 0.463, 0.573, or 0.539), tubulointerstitial damage (r = 0.794, 0.618, or 0.712) and fibrosis (r = 0.651, 0.567, or 0.469), all P < 0.01.. This study shows that the mechanisms of long-term I/R injury and immunosuppressants treatment include interstitial inflammation and caspase activation, most clearly demonstrated by the 24 kD active caspase-3.

    Topics: Animals; Apoptosis; Caspase 1; Caspase 3; Caspases; Chronic Disease; Cyclosporine; Electrophoresis, Polyacrylamide Gel; Extracellular Matrix; Fibrosis; Glomerulonephritis; Immunosuppressive Agents; Interleukin-1; Male; Mycophenolic Acid; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Tacrolimus

2005
Effect of sirolimus on renal ischaemia/reperfusion injury in normotensive and hypertensive rats.
    Transplant international : official journal of the European Society for Organ Transplantation, 2004, Volume: 17, Issue:8

    Renal ischaemia/reperfusion (I/R) injury and hypertension represent major alloantigen-independent factors contributing to the development of chronic allograft nephropathy of renal allografts. In the present study, we investigated the effect of the anti-proliferative immunosuppressant, sirolimus (SIR), in a model of accelerated renal injury in hypertensive transgenic rats (TGRs). Twenty anaesthetized uninephrectomized TGRs with renin overproduction [TGR(mREN2)27] and 20 normotensive Han SD (SD) rats as genetic controls had their renal pedicles clipped for 45 min and were subsequently treated with either SIR (0.5 mg/kg per day, orally) or placebo ( n=10 in each group) for 16 weeks, after which time the kidneys were harvested for morphological and immunohistochemical analysis. High-renin hypertension aggravated the functional and structural changes induced by I/R in SD animals: both SIR-treated and untreated TGRs exhibited significantly greater proteinuria and suffered from more severe glomerulosclerosis ( P<0.01) and vasculopathy ( P<0.01), as well as compensatory renal hypertrophy ( P<0.01) and tissue TGF-beta1 expression, than both normotensive SD groups ( P<0.01). SIR-treated SD rats showed reduced proteinuria ( P<0.01), glomerulosclerosis ( P<0.01), and TGF-beta1 expression in the glomerular epithelium and proximal tubuli ( P<0.05) compared with placebo-treated SD rats. SIR-treated TGRs had significantly lower proteinuria at week 4 after I/R ( P<0.01) than placebo-treated TGRs, but there were no significant differences thereafter. Morphological patterns were similar in treated and untreated TGRs at week 16. High-renin-induced hypertension aggravated the renal injury induced by I/R. Sirolimus treatment ameliorated some late functional and morphological changes induced by I/R injury in hypertensive TGRs but, particularly, in normotensive SD rats.

    Topics: Animals; Animals, Genetically Modified; Blood Pressure; Creatinine; Immunosuppressive Agents; Kidney Function Tests; Male; Mice; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Renal Circulation; Renin; Reperfusion Injury; Sirolimus; Urea

2004
Ischemia-reperfusion induces glomerular and tubular activation of proinflammatory and antiapoptotic pathways: differential modulation by rapamycin.
    Journal of the American Society of Nephrology : JASN, 2004, Volume: 15, Issue:10

    Ischemia-reperfusion (I-R) injury in transplanted kidney, a key pathogenic event of delayed graft function (DGF), is characterized by tubular cell apoptosis and interstitial inflammation. Akt-mammalian target of rapamycin-S6k and NF-kappaB-inducing kinase (NIK)-NF-kappaB axis are the two main signaling pathways regulating cell survival and inflammation. Rapamycin, an immunosuppressive drug inhibiting the Akt axis, is associated with a prolonged DGF. The aim of this study was to evaluate Akt and NF-kappaB axis activation in patients who had DGF and received or not rapamycin and in a pig model of I-R and the role of coagulation priming in this setting. In graft biopsies from patients who were not receiving rapamycin, phosphorylated Akt increased in proximal tubular, interstitial, and mesangial cells with a clear nuclear translocation. The same pattern of activation was observed for S6k and NIK. However, in rapamycin-treated patients, a significant reduction of S6k but not Akt and NIK activation was observed. A time-dependent activation of phosphatidylinositol 3-kinase, Akt, S6k, and NIK was observed in the experimental model with the same pattern reported for transplant recipients who did not receive rapamycin. Extensive interstitial and glomerular fibrin deposition was observed both in pig kidneys upon reperfusion and in DGF human biopsies. It is interesting that the activation of both Akt and NIK-NF-kappaB pathways was induced by thrombin in cultured proximal tubular cells. In conclusion, the data suggest that (1) coagulation may play a pathogenic role in I-R injury; (2) the Akt axis is activated after I-R, and its inhibition may explain the prolonged DGF observed in rapamycin-treated patients; and (3) NIK activation in I-R and DGF represents a proinflammatory, rapamycin-insensitive signal, potentially leading to progressive graft injury.

    Topics: Adult; Animals; Apoptosis; Biopsy, Needle; Disease Models, Animal; Female; Graft Rejection; Humans; Immunohistochemistry; Immunosuppressive Agents; Kidney Glomerulus; Kidney Transplantation; Kidney Tubules; Male; MAP Kinase Signaling System; Microscopy, Confocal; Middle Aged; NF-kappaB-Inducing Kinase; Phosphorylation; Probability; Prospective Studies; Protein Serine-Threonine Kinases; Reference Values; Reperfusion Injury; Risk Factors; Sirolimus; Swine

2004
Selectin inhibitor bimosiamose prolongs survival of kidney allografts by reduction in intragraft production of cytokines and chemokines.
    Journal of the American Society of Nephrology : JASN, 2004, Volume: 15, Issue:11

    Binding of the P-, L-, and E-selectins to sialyl Lewis(x) (sLe(x)) retards circulating leukocytes, thereby facilitating their attachment to the blood vessels of allografts. Whether the selectin inhibitor bimosiamose (BIMO; C(46)H(54)O(16) . 0.25 H(2)O [867.4 molecular weight]) inhibits the rejection process of kidney allografts in a rat model was examined. Rat recipients acutely rejected kidney allografts at a mean survival time of 8.8 +/- 0.75 d. An intravenous 7-d infusion by osmotic pump of 2.5, 5, 10, or 20 mg/kg BIMO extended kidney allograft survival to 11.5 +/- 2.2 d (P < 0.03), 25.4 +/- 11.4 d (P < 0.006), 37.4 +/- 13.6 d (P < 0.001), and 39.8 +/- 34.5 d (P < 0.01), respectively. Combination of BIMO with cyclosporine produced synergistic interactions, as documented by the combination index (CI) values of 0.34 to 0.43 (CI <1 is synergistic; CI = 1 is additive; and CI >1 is antagonistic). Similarly, BIMO interacted synergistically with sirolimus (CI = 0.64) and FTY720 (CI = 0.22). While the mechanism of immunosuppression was being analyzed, decreased infiltration of CD4(+), CD8(+), and macrophages on day 7 after grafting was observed. Multiple cytokines were also expressed, including IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12, IL-18, TNF-alpha, and IFN-gamma in kidney allografts on days 3, 5, and 7 after grafting, as measured by a ribonuclease protection assay. Furthermore, at similar time points, BIMO treatment reduced intragraft expression of P-selectin glycoprotein ligand-1, CX(3)CL1, CCL19, CCL20, and CCL2. Thus, BIMO blocks allograft rejection by reduction of intragraft expression of cytokines and chemokines.

    Topics: Animals; Chemokines; Cyclosporine; Cytokines; Drug Synergism; Graft Rejection; Graft Survival; Hexanes; Immunosuppressive Agents; Kidney; Kidney Transplantation; Male; Mannose; Rats; Rats, Inbred Strains; Reperfusion Injury; Selectins; Sirolimus

2004
Rapamycin preserves renal function compared with cyclosporine A after ischemia/reperfusion injury.
    Urology, 2003, Volume: 62, Issue:4

    To determine the effect of cyclosporine and rapamycin administration on renal function after ischemia/reperfusion injury (I/R). Cyclosporine A has known nephrotoxic effects. Thus, cyclosporine therapy subsequent to I/R injury may further exacerbate graft dysfunction. Rapamycin is a newer agent that suppresses the immune system by a different mechanism.. Male Wistar rats (250 g) were anesthetized, and the suprarenal aorta was clamped for 40 minutes. The right kidney was removed. After recovery, the rats were divided into four groups: group 1, controls, no ischemia and no treatment (n = 10); group 2, ischemia with no treatment (n = 8); group 3, ischemia plus rapamycin (0.17 mg/kg/day gavage, n = 8); and group 4, ischemia plus cyclosporine A (30 mg/kg/day intraperitoneally, n = 9). The glomerular filtration rate was measured 5 to 7 days after I/R injury using urinary iohexol clearance. Data are expressed as the mean +/- SEM, and intergroup comparisons were made using one-way analysis of variance.. The mean GFR value for the controls (no ischemia, no treatment) was 1.23 +/- 0.08 mL/min; for group 2 (ischemia, no treatment), it was 1.05 +/- 0.10 mL/min; for group 3 (ischemia plus rapamycin) 1.06 +/- 0.14 mL/min; and for group 4 (ischemia plus cyclosporine A) 0.44 +/- 0.06 mL/min (P <0.05 versus the other three groups). The mean arterial pressure was significantly lower in the ischemic rats treated with cyclosporine A (P <0.05 versus the other three groups).. After I/R injury, rapamycin may preserve renal function compared with cyclosporine treatment, because it does not have a direct vasoconstrictor effect on the renal microcirculation.

    Topics: Animals; Calcineurin; Cyclosporine; Glomerular Filtration Rate; Immunosuppressive Agents; Ischemia; Kidney; Kidney Diseases; Kidney Transplantation; Male; Nephrectomy; Postoperative Complications; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Tissue and Organ Procurement

2003
Sirolimus delays recovery of rat kidney transplants after ischemia-reperfusion injury.
    Transplantation, 2003, Dec-15, Volume: 76, Issue:11

    Sirolimus (SRL) seems to impair renal recovery from ischemic injury in animal models and delayed graft function after clinical renal transplantation. This study determined the impact of SRL on renal recovery after ischemia-reperfusion injury in a rat kidney transplant model.. Syngeneic kidneys were preserved in University of Wisconsin solution before transplantation into bilaterally nephrectomized rats. Recipients received vehicle or SRL targeting for whole-blood trough levels of 10 to 20 ng/mL as measured by high-performance liquid chromatography. Renal function was assessed by animal survival or daily serum creatinine. Tissue samples were collected for histologic examination.. Median SRL whole-blood concentrations were 16.6 +/- 1.6 ng/mL on postoperative day (POD) 1 and 12.0 +/- 0.9 ng/mL on POD 3. Transplantation of kidneys after 39 hr of cold storage resulted in 30% survival in the SRL-treated group compared with 100% survival in the control group (P=0.002). Transplantation of kidneys after 24 hr of cold storage resulted in no survival differences, but there were significant differences in renal function. Daily serum creatinine (PODs 1-4) was higher in the SRL-treated group compared with the control group (P<0.05 at all time points). Grafts from SRL-treated animals showed more severe tubular necrosis compared with control animals.. When given at therapeutic immunosuppressive doses, SRL compromises renal function after ischemia-reperfusion injury in a rat kidney transplant model. The antiproliferative effect of SRL may translate into impairment of tubular repair and regeneration necessary for recovery after such injury.

    Topics: Adenosine; Allopurinol; Animals; Creatinine; Glutathione; Immunosuppressive Agents; Insulin; Kidney; Kidney Transplantation; Organ Preservation Solutions; Raffinose; Rats; Reperfusion Injury; Sirolimus; Time Factors; Transplantation, Isogeneic; Treatment Outcome

2003
Effects of immunosuppressants, calcineurin inhibition, and blockade of endoplasmic reticulum calcium channels on free fatty acid efflux from the ischemic/reperfused rat cerebral cortex.
    Brain research, 2002, Dec-06, Volume: 957, Issue:1

    Elevated levels of free fatty acids (FFA) have been implicated in the pathogenesis of neuronal injury and death induced by cerebral ischemia. This study evaluated the effects of immunosuppressants agents, calcineurin inhibitors and blockade of endoplasmic reticulum (ER) calcium channels on free fatty acid formation and efflux in the ischemic/reperfused (I/R) rat brain. Changes in the extracellular levels of arachidonic, docosahexaenoic, linoleic, myristic, oleic and palmitic acids in cerebral cortical superfusates during four-vessel occlusion-elicited global cerebral ischemia were examined using a cortical cup technique. A 20-min period of ischemia elicited large increases in the efflux of all six FFAs, which were sustained during the 40 min of reperfusion. Cyclosporin A (CsA) and trifluoperazine, which reportedly inhibit the I/R elicited opening of a mitochondrial permeability transition (MPT) pore, were very effective in suppressing ischemia/reperfusion evoked release of all six FFAs. FK506, an immunosuppressant which does not directly affect the MPT, but is a calcineurin inhibitor, also suppressed the I/R-evoked efflux of FFAs, but less effectively than CsA. Rapamycin, a derivative of FK506 which does not inhibit calcineurin, did not suppress I/R-evoked FFA efflux. Gossypol, a structurally unrelated inhibitor of calcineurin, was also effective, significantly reducing the efflux of docosahexaenoic, arachidonic and oleic acids. As previous experiments had implicated elevated Ca(2+) levels in the activation of phospholipases with FFA formation, agents affecting endoplasmic reticulum stores were also evaluated. Dantrolene, which blocks the ryanodine receptor (RyR) channel of the ER, significantly inhibited I/R-evoked release of docosahexaenoic, arachidonic, linoleic and oleic acids. Ryanodine, which can either accentuate or block Ca(2+) release, significantly enhanced ischemia/reperfusion-elicited efflux of linoleic acid, with non-significant increases in the efflux of myristic, arachidonic, palmitic and oleic acids. Xestospongin C, an inhibitor of the inositol triphosphate (IP(3)R) channel, failed to affect I/R-evoked FFA efflux. Thapsigargin, an inhibitor of the Ca(2+)-ATPase ER uptake pump, elicited significant elevations in the efflux of myristic, arachidonic and linoleic acids, in the absence of ischemia. Collectively, the data suggest an involvement of both ER and mitochondrial Ca(2+) stores in the chain of events which lead to PLA(2) activation and

    Topics: Animals; Calcineurin; Calcineurin Inhibitors; Calcium Channels; Cerebral Cortex; Cyclosporine; Dantrolene; Endoplasmic Reticulum; Enzyme Inhibitors; Fatty Acids, Nonesterified; Gossypol; Immunosuppressive Agents; Macrocyclic Compounds; Male; Oxazoles; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Ryanodine; Sirolimus; Tacrolimus; Thapsigargin; Trifluoperazine

2002
Effect of sirolimus on ischemia/reperfusion injury in transgenic hypertensive rat.
    Transplantation proceedings, 2002, Volume: 34, Issue:8

    Topics: Animals; Animals, Genetically Modified; Hypertension, Renal; Kidney; Proteinuria; Rats; Renal Artery; Renal Veins; Reperfusion Injury; Sirolimus; Time Factors; Transforming Growth Factor beta

2002
Rapamycin impairs recovery from acute renal failure: role of cell-cycle arrest and apoptosis of tubular cells.
    American journal of physiology. Renal physiology, 2001, Volume: 281, Issue:4

    The immunosuppressive effect of rapamycin is mediated by inhibition of interleukin-2-stimulated T cell proliferation. We report for the first time that rapamycin also inhibits growth factor-induced proliferation of cultured mouse proximal tubular (MPT; IC(50) ~1 ng/ml) cells and promotes apoptosis of these cells by impairing the survival effects of the same growth factors. On the basis of these in vitro data, we tested the hypothesis that rapamycin would impair recovery of renal function after ischemic acute renal failure induced in vivo by renal artery occlusion (RAO). Rats given daily injections of rapamycin or vehicle were subjected to RAO or sham surgery. Rapamycin had no effect on the glomerular filtration rate (GFR) of sham-operated animals. In rats subjected to RAO, GFR fell to comparable levels 1 day later in vehicle- and rapamycin-treated rats (0.25 +/- 0.08 and 0.12 +/- 0.05 ml. min(-1). 300 g(-1), respectively) (P = not significant). In vehicle-treated rats subjected to RAO, GFR increased to 0.61 +/- 0.08 ml. min(-1). 300 g(-1) on day 3 (P < 0.02 vs. day 1) and then rose further to 0.99 +/- 0.09 ml. min(-1). 300 g(-1) on day 4 (P < 0.02 vs. day 3). By contrast, GFR did not improve in rapamycin-treated rats subjected to RAO over the same time period. Rapamycin also increased apoptosis of tubular cells while markedly reducing their proliferative response after RAO. Furthermore, rapamycin inhibited activation of 70-kDa S6 protein kinase (p70(S6k)) in cultured MPT cells as well as in the renal tissue of rats subjected to RAO. We conclude that rapamycin severely impairs the recovery of renal function after ischemia-reperfusion injury. This effect appears to be due to the combined effects of increased tubular cell loss (via apoptosis) and profound inhibition of the regenerative response of tubular cells. These effects are likely mediated by inhibition of p70(S6k).

    Topics: Acute Kidney Injury; Adenosine Triphosphate; Animals; Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Survival; Cells, Cultured; Cisplatin; Enzyme Activation; Epidermal Growth Factor; Glomerular Filtration Rate; Immunosuppressive Agents; Kidney Transplantation; Kidney Tubules, Proximal; Lysophospholipids; Mice; Mice, Inbred C57BL; Nephrectomy; Recovery of Function; Reperfusion Injury; Ribosomal Protein S6 Kinases; Sirolimus

2001
Immunosuppressants decrease neutrophil chemoattractant and attenuate ischemia/reperfusion injury of the liver in rats.
    The Journal of trauma, 1998, Volume: 44, Issue:3

    Neutrophils may play an important role in the development of liver ischemia/reperfusion injury. We investigated the effects of the immunosuppressants azathioprine (AZA), cyclosporine A (CsA), tacrolimus (FK506), and rapamycin (RPM) on the expression of cytokine-induced neutrophil chemoattractant (CINC) after ischemia/reperfusion of the liver.. Liver ischemia was induced in male Wistar rats by occluding the portal vein with a microvascular clip for 30 minutes. Rats received two intramuscular injections of AZA (4 mg/kg), CsA (5 mg/kg), FK506 (0.5 mg/kg), or RPM (0.5 mg/kg) 3 and 24 hours before ischemia/reperfusion of the liver.. Serum CINC concentrations in untreated animals increased, peaked 6 hours after reperfusion, and thereafter decreased gradually. Pretreatment with AZA, CsA, FK506, and RPM, however, inhibited the increase in serum CINC concentrations after reperfusion. CINC mRNA in liver tissue increased and peaked 3 hours after reperfusion, but was significantly lower in animals treated with AZA, CsA, FK506, and RPM. In vitro CINC production by Kupffer cells harvested from animals treated with AZA, CsA, FK506, or RPM 3 hours after reperfusion was also significantly lower than that observed in untreated animals. Both myeloperoxidase activity and the number of neutrophils accumulating in the liver 24 hours after reperfusion in animals treated with AZA, CsA, FK506, and RPM were significantly lower than in untreated animals. This correlated with lower serum aspartate transaminase, alanine transaminase, and lactate dehydrogenase levels in animals treated with AZA, CsA, FK506, and RPM 24 hours after reperfusion.. The immunosuppressants AZA, CsA, FK506, and RPM reduce neutrophil accumulation and attenuate ischemia/reperfusion injury of the liver.

    Topics: Animals; Azathioprine; Cyclosporine; Drug Evaluation, Preclinical; Immunosuppressive Agents; Interleukin-16; Liver; Male; Neutrophils; Polyenes; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; Tacrolimus; Time Factors

1998
Beneficial effects of cyclosporine and rapamycin in small bowel ischemic injury.
    The Journal of surgical research, 1996, Volume: 65, Issue:2

    Gut ischemia has been implicated in the pathogenesis of necrotizing enterocolitis. Cyclosporine A and rapamycin, both potent novel immunosuppressants which act on signal transduction pathways in CD4+ T-cells, could potentially modulate immune/inflammatory cellular reactions involved in tissue ischemia/reperfusion injury. We hypothesized that cyclosporine A and rapamycin would preserve mucosal cell function and attenuate inflammatory T-cell-mediated cellular changes associated with small bowel ischemic injury. Forty Sprague-Dawley rats underwent 60 min of gut ischemia by vascular occlusion of the superior mesenteric vessels. Animals were randomized to four groups (n = 10): cyclosporine A (CSA, 5 mg/kg/day SQ), rapamycin (RAP, 2 mg/kg/day SQ), cyclosporine A and rapamycin (C&R), and vehicle given to controls (CON). Following 1 hr of reperfusion, small bowel was harvested for xanthine oxidase (XO, units/mg protein) and maltase (MALT, mM substrate degraded/min/g protein) assays. Blood was obtained from the portal vein for tumor necrosis factor-alpha (TNF-alpha, pg/ml) assay. The results of the study are presented below (mean +/- SEM, *, P < 0.05 versus controls). (Table in text) The results indicate that cyclosporine and rapamycin each play a significant role in attenuating ischemia/reperfusion injury in the gut. These data suggest that there are cytoprotective and anti-inflammatory mechanisms of these drugs independent of T-cell signal transduction that provide some protective effect in small bowel ischemia. Furthermore, T-cell-mediated immune mechanisms may not be associated with the adverse effects of small bowel ischemia/reperfusion injury. Additional investigation will be necessary in order to define the role of T-cell-mediated immune injury in the gut and how this relates to the beneficial effect of immunosuppression in small bowel mucosal ischemic injury.

    Topics: alpha-Glucosidases; Animals; Cyclosporine; Immunosuppressive Agents; Intestinal Mucosa; Intestine, Small; Ischemia; Male; Polyenes; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sirolimus; Tumor Necrosis Factor-alpha; Xanthine Oxidase

1996