sirolimus and Acute-Kidney-Injury

The mammalian target of rapamycin (mTOR) signaling pathway is crucial in maintaining cell growth and metabolism. The mTOR protein kinase constitutes the catalytic subunit of two multimeric protein complexes called mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). As such, this pathway is indispensable for many organs, including the kidney. Since its discovery, mTOR has been associated with major renal disorders such as acute kidney injury, chronic kidney disease, and polycystic kidney disease. On top of that, emerging studies using pharmacological interventions and genetic disease models have unveiled mTOR role in renal tubular ion handling. Along the tubule, mTORC1 and mTORC2 subunits are ubiquitously expressed at mRNA level. Nevertheless, at the protein level, current studies suggest that a tubular segment-specific balance between mTORC1 and mTORC2 exists. In the proximal tubule, mTORC1 regulates nutrients transports through various transporters located in this segment. On the other hand, in the thick ascending limb of the loop of Henle, both complexes play a role in regulating NKCC2 expression and activity. Lastly, in the principal cells of the collecting duct, mTORC2 determines Na

Topics: Acute Kidney Injury; Biological Transport; Humans; Kidney; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Although calcineurin inhibitor drugs have been the mostly used therapy in modern immunosuppression in kidney transplantation, their effect on kidney allograft dysfunction has been suboptimal as far as preservation of kidney function is concerned. Additionally, there are metabolic and other nonmetabolic effects including increased risk of malignancy that has necessitated the use of mammalian target of rapamycin inhibitors to reduce exposure to calcineurin inhibitors. Mammalian target of rapamycin inhibitors, both sirolimus and everolimus, have been studied in several trials to facilitate preservation of kidney function with variable effects on kidney allograft function and immunogenicity. Preservation of kidney function is increasingly becoming the mainstay of immunosuppression not only in kidney transplantation, but also in extrakidney transplantation. The best kidney outcomes have been reported in calcineurin inhibitor withdrawal studies using mammalian target of rapamycin inhibitors, in kidney transplant recipients with stable kidney function. This review article summarizes data from several studies in which mammalian target of rapamycin inhibitors have been used to reduce exposure to or withdraw calcineurin inhibitors in an attempt to preserve kidney function.

Topics: Acute Kidney Injury; Animals; Calcineurin Inhibitors; Graft Rejection; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Kidney Transplantation; Sirolimus

The calcineurin inhibitors (CNIs) remain the standard of care for maintenance immunosuppression following renal transplantation. CNIs have demonstrated their effectiveness in reducing acute cellular rejection; however, some evidence suggests that these compounds negatively affect native renal function and are associated with allograft injury in renal transplant recipients. CNIs have also been linked with hypertension, new-onset diabetes after transplantation, tremor, and thrombotic microangiopathy, which have significant consequences for long-term allograft function and patient health overall. Thus, converting patients to a non-CNI-based regimen may improve renal function and also provide extrarenal benefits. A number of studies have been conducted that explore CNI conversion strategies in renal transplant recipients in an effort to improve long-term allograft function and survival. These include converting to alternative, non-nephrotoxic, maintenance immunosuppressants, such as the mammalian target of rapamycin inhibitors (sirolimus and everolimus) and the costimulation blocker belatacept. In this review of literature, evidence for the potential renal and extrarenal benefits of conversion to these non-CNI-based regimens is evaluated. Clinical challenges, including the adverse event profiles of non-CNI-based regimens and the selection of candidates for conversion, are also examined.

Topics: Abatacept; Acute Kidney Injury; Calcineurin Inhibitors; Everolimus; Graft Survival; Humans; Immunoconjugates; Immunosuppressive Agents; Kidney Transplantation; Patient Selection; Sirolimus

The mTOR pathway plays an important role in a number of common renal diseases, including acute kidney injury (AKI), diabetic nephropathy (DN), and polycystic kidney diseases (PKD). The activity of mTOR complex 1 (mTORC1) is necessary for renal regeneration and repair after AKI, and inhibition of mTORC1 by rapamycin has been shown to delay recovery from ischemic AKI in animal studies, and to prolong delayed graft function in humans who have received a kidney transplant. For this reason, administration of rapamycin should be delayed or discontinued in patients with AKI until full recovery of renal function has occurred. On the other hand, inappropriately high mTORC1 activity contributes to the progression of the metabolic syndrome, the development of type 2 diabetes, and the pathogenesis of DN. In addition, chronic hyperactivity of mTORC1, and possibly also mTORC2, contributes to cyst formation and enlargement in a number of forms of PKD. Inhibition of mTOR, using either rapamycin (which inhibits predominantly mTORC1) or "catalytic" inhibitors (which effectively inhibit both mTORC1 and mTORC2), provide exciting possibilities for novel forms of treatment of DN and PKD. In this second part of the review, we will examine the role of mTOR in the pathophysiology of DN and PKD, as well as the potential utility of currently available and newly developed inhibitors of mTOR to slow the progression of DN and/or PKD.

Topics: Acute Kidney Injury; Diabetic Nephropathies; Humans; Kidney; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Polycystic Kidney Diseases; Proteins; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Renal tubular cells die by apoptosis as well as necrosis in experimental models of ischemic and toxic acute renal failure as well as in humans with acute tubular necrosis. It is not yet possible, however, to determine the relative contribution of these two forms of cell death to loss of renal tubular cells in acute tubular necrosis. The beneficial effect of administering growth factors to animals with acute tubular necrosis is probably related to the potent antiapoptotic (survival) effects of growth factors as well as to their proliferative effects. Rapamycin inhibits both of these effects of growth factors and delays the recovery of renal function after acute tubular necrosis by inhibiting renal tubular cell regeneration and by increasing renal tubular cell loss by apoptosis. The administration of caspase inhibitors ameliorates ischemia-reperfusion injury in multiple organs including the kidney. However, the extent to which this protective effect of caspase inhibition is caused by reduced intrarenal inflammation, or by amelioration of renal tubular cell loss due to apoptosis, remains uncertain. In addition to caspase inhibition, the apoptotic pathway offers many potential targets for therapeutic interventions to prevent renal tubular cell apoptosis.

Topics: Acute Kidney Injury; Apoptosis; Caspase Inhibitors; Cell Adhesion; Cisplatin; Growth Substances; Guanosine Triphosphate; Humans; Ischemia; Kidney Tubules; Necrosis; Sirolimus

Acute and chronic nephrotoxicity frequently limits the therapeutic benefits of immunosuppressive therapy for transplant and autoimmune indications. The clinical aspects, pathophysiology, and relevant pharmacology of current and future immunosuppressive drugs are reviewed in this paper. Insights gained from experimental models of chronic nephrotoxicity associated with tubulointerstitial fibrosis are presented.

Topics: Acute Kidney Injury; Animals; Cyclosporins; Hemolytic-Uremic Syndrome; Humans; Hypertension; Immunosuppressive Agents; Kidney; Kidney Failure, Chronic; Kidney Transplantation; Polyenes; Sirolimus; Tacrolimus

Drugs used to modify the immune response in solid organ transplantation or autoimmune disease may cause dose-related nephrotoxicity. Cyclosporine, FK506, cyclosporine G, and rapamycin have all been studied experimentally and to a more limited extent in patients. This paper summarizes this literature using data from clinically relevant animal models.

Topics: Acute Kidney Injury; Animals; Cyclosporine; Humans; Hypertension, Renal; Immunosuppressive Agents; Kidney Failure, Chronic; Polyenes; Sirolimus; Tacrolimus

Based on its success as a transplant immunosuppressor, there is intense interest in using rapamycin in the treatment of progressive glomerulopathies involving native kidneys. However, we call attention to the potential toxicity associated with the use of rapamycin in this setting.. We conducted a study to examine the efficacy and safety of rapamycin in patients with progressive chronic renal failure. Eleven patients with either focal segmental glomerulosclerosis, immunoglobulin A nephropathy, membranous nephropathy or membrano-proliferative glomerulonephritis and progressive renal failure (defined as an increase in >25% of baseline serum creatinine over the last year or loss of glomerular filtration rate > or =5 ml/min/year as determined by the Cockcroft-Gault formula), proteinuria > or =1.0 g/24 h and with a creatinine clearance of > or 20 ml/min/1.73 m(2) were entered into a 12 month study. Patients were treated with rapamycin, starting at 5 mg/day, orally, aiming for target blood levels of 7-10 ng/dl. All patients were on treatment with an angiotensin-converting enzyme inhibitor and/or an angiotensin receptor blocker, aiming to control blood pressure < or =145/90 mmHg.. Six patients developed acute renal failure, defined as an increase in serum creatinine > or =0.5 mg/dl (baseline: 3.2+/-0.9 mg/dl; peak: 5.6+/-1.6 mg/dl; P<0.01, paired t-test). In four patients, discontinuation of the drug resulted in improvement of renal function close to baseline levels. One patient required haemodialysis and had no subsequent recovery of renal function. In another patient, renal function recovered after discontinuation of the drug and then rapamycin was resumed at a lower dose when creatinine returned to baseline. This resulted in a second acute increase in serum creatinine that failed to return to baseline when the medication was discontinued. Four other patients had the following adverse events: skin rash, severe hypertriglyceridaemia, diarrhoea and hyperkalaemia. In none of the subjects were rapamycin levels >15 ng/dl.. Rapamycin can cause nephrotoxicity in some patients with chronic glomerulopathies. Whether the toxicity is solely related to rapamycin, due to the combination of proteinuria and rapamycin, or other unknown factor use is presently undetermined.

Topics: Acute Kidney Injury; Adult; Creatinine; Humans; Immunosuppressive Agents; Kidney; Kidney Failure, Chronic; Sirolimus; Transplantation Conditioning; Transplantation Immunology

For nearly five decades, cisplatin has played an important role as a standard chemotherapeutic agent and been prescribed to 10-20% of all cancer patients. Although nephrotoxicity associated with platinum-based agents is well recognized, treatment of cisplatin-induced acute kidney injury is mainly supportive and no specific mechanism-based prophylactic approach is available to date. Here, we postulated that systemically delivered rapamycin perfluorocarbon nanoparticles (PFC NP) could reach the injured kidneys at sufficient and sustained concentrations to mitigate cisplatin-induced acute kidney injury and preserve renal function. Using fluorescence microscopic imaging and fluorine magnetic resonance imaging/spectroscopy, we illustrated that rapamycin-loaded PFC NP permeated and were retained in injured kidneys. Histologic evaluation and blood urea nitrogen (BUN) confirmed that renal structure and function were preserved 48 h after cisplatin injury. Similarly, weight loss was slowed down. Using western blotting and immunofluorescence staining, mechanistic studies revealed that rapamycin PFC NP significantly enhanced autophagy in the kidney, reduced the expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), as well as decreased the expression of the apoptotic protein Bax, all of which contributed to the suppression of apoptosis that was confirmed with TUNEL staining. In summary, the delivery of an approved agent such as rapamycin in a PFC NP format enhances local delivery and offers a novel mechanism-based prophylactic therapy for cisplatin-induced acute kidney injury.

Topics: Acute Kidney Injury; Apoptosis; Cisplatin; Fluorocarbons; Humans; Kidney; Nanoparticles; Sirolimus

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

Hypercholesterolemia can aggravate contrast-induced acute kidney injury, and the exacerbation of renal tubular epithelial cell (RTEC) injury is a major cause. However, the exact mechanisms remain obscure. Mitophagy, a type of autophagy, selectively eliminates damaged mitochondria and reduces mitochondrial oxidative stress, which is strongly implicated in cell homeostasis and acute kidney injury. Oxidized low-density lipoprotein (Ox-LDL) is accumulated in hypercholesterolemia and has a cytotoxic effect. This study aimed to determine whether and how ox-LDL exacerbates contrast-induced injury in RTECs and to further explore whether PINK1/Parkin-dependent mitophagy is involved in this process. Iohexol and ox-LDL were used alone or in combination to treat HK-2 cells. Rapamycin pretreatment was utilized to enhance mitophagy. Cell viability, apoptosis, mitochondrial membrane potential (MMP) and mitochondrial reactive oxygen species (mtROS) were detected by cell counting kit-8, TUNEL staining, JC-1 kit and MitoSOX fluorescence, respectively. The expression of mitophagy-related proteins (including PINK1, Parkin, and so on) and cleaved caspase-3 was confirmed by western blot. Colocalization of MitoTracker-labeled mitochondria and LysoTracker-labeled lysosomes was observed by fluorescence microscopy to evaluate mitophagy. The results of our study showed that ox-LDL aggravated MMP decline, mtROS release and apoptosis in iohexol-treated HK-2 cells, accompanied by a further increased autophagy level. Enhancement of PINK1/Parkin-dependent mitophagy by rapamycin alleviated apoptosis and mitochondrial injury in HK-2 cells in response to iohexol under ox-LDL condition. Therefore, our findings indicate that ox-LDL aggravates contrast-induced injury of RTECs by increasing mitochondrial damage and mitochondrial oxidative stress, which may be associated with the relative insufficiency of PINK1/Parkin-dependent mitophagy.

Topics: Acute Kidney Injury; Apoptosis; Epithelial Cells; Humans; Hypercholesterolemia; Iohexol; Lipoproteins, LDL; Protein Kinases; Reactive Oxygen Species; Sirolimus; Ubiquitin-Protein Ligases

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

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

To study how to effectively prevent or reduce renal injury caused by contrast agents in diabetic patients.. Sprague Dawley (SD) rats were bred with a high-fat diet for eight weeks, then intraperitoneally injected with Streptozotocin (STZ) to prepare the diabetes model. Rats were treated with Iodixanol to prepare a contrast-induced acute kidney injury (CIAKI) model. Moreover, 3-methyladenine (3-MA), an autophagy inhibitor, was administrated to diabetic rats with or without Rapamycin treatment. Serum creatinine (SCr) and blood urea nitrogen (BUN) were examined using Biochemical detector. Kidney injury molecule-1 (KIM-1), N-acetyl-β-D-amino glycosidase (NAG) in urine, inflammatory and oxidative stress factors in serum were determined by ELISA. The expression level of ROS was quantified by immunofluorescence (IF). The protein expressions of Bax, BCl-2, LC3, Beclin1, mTOR and p70S6K in renal tissue were detected by Western blot.. Rapamycin was demonstrated to improve renal injury induced by Iodixanol diabetic rats, decrease the levels of SCr, BUN, KIM-1, NAG, improve renal functions, reduce inflammatory response and oxidative stress injury, down-regulate Bax, while up-regulate BCl-2 and inhibit apoptosis. Moreover, Rapamycin could inhibit the phosphorylation of mTOR/p70S6K pathway-associated proteins, activate autophagy and increase the levels of LC3 and Beclin1. After treatment with 3MA, an inhibitor of mTOR/p70S6K signaling pathway, the protective effects of Rapamycin on CIAKI were weakened.. Rapamycin can alleviate renal injury induced by Iodixanol diabetic rats, and its regulatory mechanisms may be related to the regulation of mTOR/p70S6K signaling pathway and the activating autophagy.

Topics: Acute Kidney Injury; Animals; Apoptosis; Autophagy; Diabetes Mellitus, Experimental; Kidney; Male; Phosphorylation; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Streptozocin; TOR Serine-Threonine Kinases; Triiodobenzoic Acids

Small-molecule protein kinase inhibitors (PKIs) have substantially improved clinical outcomes of various diseases. However, some studies suggested these agents might induce acute kidney injury (AKI). This study was designed to comprehensively assess the adverse events of AKI in real-world patients receiving small-molecule PKIs using the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS).. The FAERS data between 2004 and 2019 were extracted to describe the characteristics of AKI cases after the use of small-molecule PKIs approved by the FDA. The reporting odds ratio (ROR) with 95% confidence interval (CI) for AKI was calculated for each small-molecule PKI agent. A disproportionality signal was defined when the lower limit of 95% CI > 1.. Among the 462,020 adverse event reports for small-molecule PKIs, 9970 (2.16%) were identified as AKI cases. The median AKI onset time was 32 (interquartile range 11-124) days after the initiation of small-molecule PKI treatment. A total of 61.38% and 26.04% of AKI cases resulted in hospitalization and death, respectively. Based on RORs, 14 of 52 small-molecule PKIs yielded disproportionality signals for AKI, including six VEGFR inhibitors, three mTOR inhibitors and five small-molecule PKIs with other targets. The agents with the highest AKI RORs were entrectinib (ROR 6.40, 95% CI 2.23, 18.34), sirolimus (ROR 3.76, 95% CI 3.45, 4.09), and cobimetinib (ROR 3.40, 95% CI 2.69, 4.28).. Analysis of the FAERS data helped identify the small-molecule PKIs that were most frequently reported for AKI. Further investigations are needed to confirm these potential risks.

Topics: Acute Kidney Injury; Adolescent; Adult; Adverse Drug Reaction Reporting Systems; Aged; Azetidines; Benzamides; Female; Hospital Mortality; Hospitalization; Humans; Indazoles; Male; Middle Aged; Odds Ratio; Pharmacovigilance; Piperidines; Protein Kinase Inhibitors; Retrospective Studies; Risk Assessment; Sirolimus; United States; United States Food and Drug Administration; Young Adult

Autophagy plays an important role in the pathogenesis of acute kidney injury (AKI). Although autophagy activation was shown to be associated with an increased lifespan and beneficial effects in various pathologies, the impact of autophagy activators, particularly, rapamycin and its analogues on AKI remains obscure. In our study, we explored the effects of rapamycin treatment in in vivo and in vitro models of ischemic and cisplatin-induced AKI. The impact of rapamycin on the kidney function after renal ischemia/reperfusion (I/R) or exposure to the nephrotoxic agent cisplatin was assessed by quantifying blood urea nitrogen and serum creatinine and evaluating the content of neutrophil gelatinase-associated lipocalin, a novel biomarker of AKI. In vitro experiments were performed on the primary culture of renal tubular cells (RTCs) that were subjected to oxygen-glucose deprivation (OGD) or incubated with cisplatin under various rapamycin treatment protocols. Cell viability and proliferation were estimated by the MTT assay and real-time cell analysis using an RTCA iCELLigence system. Although rapamycin inhibited mTOR (mammalian target of rapamycin) signaling, it failed to enhance the autophagy and to ameliorate the severity of AKI caused by ischemia or cisplatin-induced nephrotoxicity. Experiments with RTCs demonstrated that rapamycin exhibited the anti-proliferative effect in primary RTCs cultures but did not protect renal cells exposed to OGD or cisplatin. Our study revealed for the first time that the mTOR inhibitor rapamycin did not prevent AKI caused by renal I/R or cisplatin-induced nephrotoxicity and, therefore, cannot be considered as an ideal mimetic of the autophagy-associated nephroprotective mechanisms (e.g., those induced by caloric restriction), as it had been suggested earlier. The protective action of such approaches like caloric restriction might not be limited to mTOR inhibition and can proceed through more complex mechanisms involving alternative autophagy-related targets. Thus, the use of rapamycin and its analogues for the treatment of various AKI forms requires further studies in order to understand potential protective or adverse effects of these compounds in different contexts.

Topics: Acute Kidney Injury; Animals; Antineoplastic Agents; Cells, Cultured; Cisplatin; Glucose; Ischemia; Kidney Tubules; Male; Oxygen; Protective Agents; Rats; Sirolimus; TOR Serine-Threonine Kinases

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

mTOR (mammalian target of rapamycin) signaling has emerged as a key regulator in a wide range of cellular processes ranging from cell proliferation, immune responses, and electrolyte homeostasis. mTOR consists of 2 distinct protein complexes, mTORC1 (mTOR complex 1) and mTORC2 (mTOR complex 2) with distinct downstream signaling events. mTORC1 has been implicated in pathological conditions, such as cancer and type 2 diabetes mellitus in humans, and inhibition of this pathway with rapamycin has been shown to attenuate salt-induced hypertension in Dahl salt-sensitive rats. Several studies have found that the mTORC2 pathway is involved in the regulation of renal tubular sodium and potassium transport, but its role in hypertension has remained largely unexplored. In the present study, we, therefore, determined the effect of mTORC2 inhibition with compound PP242 on salt-induced hypertension and renal injury in salt-sensitive rats. We found that PP242 not only completely prevented but also reversed salt-induced hypertension and kidney injury in salt-sensitive rats. PP242 exhibited potent natriuretic actions, and chronic administration tended to produce a negative Na

Topics: Acute Kidney Injury; Animals; Blood Pressure; Cell Proliferation; Disease Models, Animal; Hypertension; Immunosuppressive Agents; Male; Rats; Rats, Inbred Dahl; Signal Transduction; Sirolimus; Sodium Chloride, Dietary; TOR Serine-Threonine Kinases

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

Contrast induced-acute kidney injury (CI-AKI) is one of the most common causes of acute kidney injury (AKI) in hospitalized patients. Mitophagy, the selective elimination of mitochondria via autophagy, is an important mechanism of mitochondrial quality control in physiological and pathological conditions. In this study, we aimed to determine effects of iohexol and iodixanol on mitochondrial reactive oxygen species (ROS), mitophagy and the potential role of mitophagy in CI-AKI cell models.. Cell viability was measured by cell counting kit-8. Cell apoptosis, mitochondrial ROS and mitochondrial membrane potential were detected by western blot, MitoSOX fluorescence and TMRE staining respectively. Mitophagy was detected by the colocalization of LC3-FITC with MitoTracker Red, western blot and electronic microscope.. The results showed that mitophagy was induced in human renal tubular cells (HK-2 cells) under different concentrations of iodinated contrast media. Mitochondrial ROS displayed increased expression after the treatment. Rapamycin (Rap) enhanced mitophagy and alleviated contrast media induced HK-2 cells injury. In contrast, autophagy inhibitor 3-methyladenine (3-MA) down-regulated mitophagy and aggravated cells injury.. Together, our finding indicates that iohexol and iodixanol contribute to the generation of mitochondrial ROS and mitophagy. The enhancement of mitophagy can effectively protect the kidney from iodinated contrast (iohexol)-induced renal tubular epithelial cells injury.

Topics: Acute Kidney Injury; Adenine; Apoptosis; Autophagy; Cell Line; Contrast Media; Epithelial Cells; Humans; Iodine; Iohexol; Kidney Tubules; Membrane Potential, Mitochondrial; Microscopy, Electron, Transmission; Microscopy, Fluorescence; Mitochondria; Mitophagy; Reactive Oxygen Species; Sirolimus; Triiodobenzoic Acids

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

Mechanistic target of rapamycin complex 1 (mTORC1) signaling is active in inflammation, but its involvement in septic acute kidney injury (AKI) has not been shown. mTORC1 activation (p-S6) in renal fibroblasts was increased in a mouse AKI model induced by 1.5 mg/kg lipopolysaccharide (LPS). Deletion of tuberous sclerosis complex 1 (TSC1), an mTORC1 negative regulator, in fibroblasts (Fibro-TSC1

Topics: Acute Kidney Injury; Animals; Apoptosis; Endothelin-1; Female; Fibroblasts; Immunosuppressive Agents; Kidney; Lipopolysaccharides; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; Signal Transduction; Sirolimus; Tuberous Sclerosis Complex 1 Protein

Semaphorin 3A (sema 3A) is one of a class of secretory proteins belonging to a family of axon-directed factors found in podocytes, distal tubules, and collecting tubes of the kidney. It is considered to be a potential target molecule involved in the mammalian target of the rapamycin (mTOR) pathway in renal injury or renal diseases, but it has an unknown role in the course of hexavalent chromium-Cr(VI) induced nephrotoxicity. In the present study, an acute kidney injury (AKI) model in rats or cultured tubular epithelial HK-2 cells was employed for Cr(VI) exposure alone or in combination with rapamycin (Rap) or N-acetyl-l-cysteine (NAC) or recombinant sema 3A. The methods of histopathology, biochemics, and western blotting were applied to evaluate tubular injury and the role of sema 3A. The results showed that a significant increase of urinary sema 3A indicates an early occurrence of AKI exposed to Cr(VI), accompanied with a significant increase of tubular injury score and phosphorylated mTOR proteins. Further, Cr(VI) treatment, in combination with pretreatment of the mTOR pathway inhibitor, Rap, showed a considerably stronger protective effect of Rap in protecting against Cr(VI)-induced nephrotoxicity than that seen with the free radical scavenger NAC, highlighting the dominant renal protective role of the mTOR pathway in inhibiting toxicity by downregulating the expressed levels of sema 3A in renal tissue. This study has demonstrated that an increased expression of sema 3A occurs in Cr(VI)-induced AKI resulting from activation of the mTOR pathway, and that inhibition of this pathway has been shown to decrease the severity of the toxicity. In conclusion, this study has shown that increased urinary sema 3A is indicative of an activated mTOR pathway and is a valuable biomarker of the early AKI induced by Cr(VI) exposure.

Topics: Acute Kidney Injury; Animals; Biomarkers; Cell Line; Cell Survival; Chromium; Disease Models, Animal; Humans; Kidney Function Tests; Kidney Tubules, Proximal; Male; Oxidative Stress; Rats, Sprague-Dawley; Semaphorin-3A; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

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

Cisplatin is a widely used chemotherapeutic drug with notorious toxicity in the kidneys, which involves mitochondrial dysfunction and damage in renal tubular cells. Mitophagy is a form of selective autophagy that removes damaged or dysfunctional mitochondria to maintain cellular homeostasis. In this study, we have used mouse and cell models to examine the role and regulation of mitophagy in cisplatin nephrotoxicity. Cisplatin treatment was associated with the activation of autophagy and mitophagy. Rapamycin, a pharmacological inhibitor of mTOR, stimulated autophagy and mitophagy, and alleviated the development of cisplatin nephrotoxicity. PINK1 and Parkin were increased in kidney tissues during cisplatin treatment of mice. In PINK1 or Parkin gene knockout mouse models, both basal and cisplatin-induced mitophagy in kidneys were defective. Compared with wild-type littermates, PINK1 and Parkin knockout mice showed more severe renal functional loss, tissue damage, and apoptosis during cisplatin treatment. The results suggest that PINK1/Parkin-mediated mitophagy is activated in cisplatin nephrotoxicity and has a protective role against kidney injury.

Topics: Acute Kidney Injury; Animals; Antineoplastic Agents; Autophagosomes; Autophagy; Cell Line; Cisplatin; Gene Expression Regulation; Kidney Function Tests; Kidney Tubules, Proximal; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; Mitophagy; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Ubiquitin-Protein Ligases

The mammalian target of rapamycin (mTOR) signal controls innate and adaptive immune response in multiple immunoregulatory contexts. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells of potent immunosuppressive capacity. In this study, we aimed to investigate the role of MDSCs in the protection of acute kidney injury (AKI) and the regulation of mTOR signal on MDSC's protective role in this context. In mice AKI model, rapamycin administration was associated with improved renal function, restored histological damage and decreased CD4

Topics: Acute Kidney Injury; Animals; Arginase; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Differentiation; Cell Proliferation; Disease Models, Animal; Immunosuppressive Agents; Interferon-gamma; Interleukin-1beta; Interleukin-6; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Myeloid Cells; Myeloid-Derived Suppressor Cells; Nitric Oxide Synthase Type II; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

There is a paucity of data evaluating acute kidney injury (AKI) incidence and its relationship with the tacrolimus-sirolimus (Tac-Sir) concentrations in the setting of reduced-intensity conditioning (RIC) after allogeneic stem cell transplantation (allo-HSCT). This multicenter retrospective study evaluated risk factors of AKI defined by 2 classification systems, Kidney Disease Improving Global Outcome (KDIGO) score and "Grade 0-3 staging," in 186 consecutive RIC allo-HSCT recipients with Tac-Sir as graft-versus-host disease prophylaxis. Conditioning regimens consisted of fludarabine and busulfan (n = 53); melphalan (n = 83); or a combination of thiotepa, fludarabine, and busulfan (n = 50). A parametric model, with detailed Tac-Sir consecutive blood levels, describing time to AKI was developed using the NONMEM software version 7.4. Overall, 81 of 186 (44%) RIC allo-HSCT recipients developed AKI with a cumulative incidence of 42% at a median follow-up of 25 months. Time to AKI was best described using a piecewise function. AKI-predicting factors were melphalan-based conditioning regimen (HR, 1.96; P < .01), unrelated donor (HR, 1.79; P = .04), and tacrolimus concentration: The risk of AKI increased 2.3% per each 1-ng/mL increase in tacrolimus whole blood concentration (P < .01). In multivariate analysis, AKI grades 2 and 3 according to KDIGO staging were independent risk factors for 2-year nonrelapse mortality (HR, 2.8; P = .05; and HR, 6.6; P < .0001, respectively). According to the KDIGO score, overall survival decreased with the increase in severity of AKI: 78% for patients without AKI versus 68%, 50%, and 30% for grades 1, 2, and 3, respectively (P < .0001). In conclusion, AKI is frequent after Tac-Sir-based RIC allo-HSCT and has a negative impact on outcome. This study presents the first predictive model describing time to AKI as a function of tacrolimus drug concentration.

Topics: Acute Kidney Injury; Adult; Aged; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Male; Middle Aged; Retrospective Studies; Risk Factors; Sirolimus; Tacrolimus; Transplantation Conditioning; Young Adult

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

Autophagy enables cells to digest endogenous/exogenous waste products, thus potentially prolonging the cellular lifespan. Early endothelial progenitor cells (eEPCs) protect mice from ischemic acute kidney injury (AKI). The mid-term prognosis in AKI critically depends on vascular rarefication and interstitial fibrosis with the latter partly being induced by mesenchymal transdifferentiation of endothelial cells (EndoMT). This study aimed to determine the impact of eEPC preconditioning with different autophagy inducing agents [suberoylanilide hydroxamic acid (SAHA)/temsirolimus] in ischemic AKI.. Male C57/Bl6 N mice were subjected to bilateral renal ischemia (40 min). Animals were injected with either untreated, or SAHA- or temsirolimus-pretreated syngeneic murine eEPCs at the time of reperfusion. Mice were analyzed 48 h and 4 weeks later. In addition, cultured eEPCs were treated with transforming growth factor (TGF)-β ± SAHA, autophagy (perinuclear LC3-II), and stress-induced premature senescence (SIPS-senescence-associated β-galactosidase, SA-β-Gal), and were evaluated 96 h later.. Cultured eEPCs showed reduced perinuclear density of LC3-II + vesicles and elevated levels of SA-β-Gal after treatment with TGF-β alone, indicating impaired autophagy and aggravated SIPS. These effects were completely abrogated by SAHA. Systemic administration of either SAHA or tems pretreated eEPCs resulted in elevated intrarenal endothelial p62 at 48 h and 4 weeks, indicating stimulated endothelial autophagy. This effect was most pronounced after injection of SAHA-treated eEPCs. At 4 weeks endothelial expression of mesenchymal alpha-smooth muscle actin (αSMA) was reduced in animals receiving untreated and SAHA-pretreated cells. In addition, SAHA-treated cells reduced fibrosis at week 4. Tems in contrast aggravated EndoMT. Postischemic renal function declined after renal ischemia and remained unaffected in all experimental cell treatment groups.. In ischemic AKI, intrarenal endothelial autophagy may be stabilized by systemic administration of pharmacologically preconditioned eEPCs. Early EPCs can reduce postischemic EndoMT and fibrosis in the mid-term. Autophagy induction in eEPCs either increases or decreases the mesenchymal properties of intrarenal endothelial cells, depending on the substance being used. Thus, endothelial autophagy induction in ischemic AKI, mediated by eEPCs is not a renoprotective event per se.

Topics: Actins; Acute Kidney Injury; Animals; Autophagy; beta-Galactosidase; Cells, Cultured; Disease Models, Animal; Endothelial Progenitor Cells; Epithelial-Mesenchymal Transition; Fibrosis; Hydroxamic Acids; Ischemia; Kidney; Male; Mice, Inbred C57BL; Microtubule-Associated Proteins; Phenotype; Sirolimus; Time Factors; Transforming Growth Factor beta; Vorinostat

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

Allogeneic hematopoietic cell transplantation is a potential curative treatment option for various malignant and nonmalignant hematologic disorders. Patients undergoing an allogeneic hematopoietic cell transplant are prescribed immune-suppressant therapies to facilitate hematopoietic donor-cell engraftment and prevent graft-versus-host disease. Drug-drug interactions may occur, owing to exposure to complex multidrug regimens with narrow therapeutic windows and high toxicity profiles. Here, we describe a unique case of a 65-year-old man with poor-risk acute myeloid leukemia who underwent a matched-sibling hematopoietic cell allograft. Sirolimus and tacrolimus were used for graft-versus-host disease prophylaxis. He developed oral thrush requiring treatment with clotrimazole troches, which subsequently resulted in serious renal toxicity attributed to supratherapeutic levels of sirolimus and tacrolimus. Patient renal function improved after temporarily holding both immune suppressants, and administering phenytoin to help induce sirolimus and tacrolimus metabolism. This case highlights sudden and serious toxicities that resulted from clotrimazole-sirolimus and clotrimazole-tacrolimus drug-drug interactions, even when administered topically.

Topics: Acute Kidney Injury; Aged; Clotrimazole; Creatinine; Hematopoietic Stem Cell Transplantation; Humans; Male; Sirolimus; Tacrolimus; Transplantation, Homologous

The mechanism of podocyte injury observed with the use of rapamycin (RPM) remains unclear. The conversion from calcineurin inhibitors (CNIs) to RPM in kidney transplant recipients has been associated with a higher incidence of proteinuria and renal injury. In this study, we performed proteomic analyses to investigate the alteration of protein expression in mouse podocytes treated with RPM in comparison with CNI/RPM combination.. Immortalized mouse podocytes were treated with 20 nmol/L RPM or 20 nmol/L RPM + 1 μg/mL cyclosporine. Podocyte proteins were separated by 2-dimensional polyacrylamide gel electrophoresis (2DE) and identified by matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry and peptide fingerprinting. Selected proteins were analyzed by means of Western blot assay.. We identified 36 differently expressed proteins after isolated RPM or CNI/RPM combination treatment in cultured mouse podocytes. There are 3 distinct patterns of protein expression: (1) potentiated down- or upregulation of proteins by CNI/RPM treatment compared with isolated RPM treatment (n = 4); (2) partial offset of down-regulation by CNI/RPM in comparison with RPM treatment (n = 25); (3) no difference in down-regulation between RPM and CNI/RPM treatment (n = 5). We found a significant interplay between RPM and CNI on the expression of the selected proteins in mouse podocytes. This might explain the higher incidence of proteinuria by CNI/RPM combination in clinical settings.. Further study is required to elucidate the target protein associated with RPM-induced podocyte injury.

Topics: Acute Kidney Injury; Animals; Calcineurin Inhibitors; Cells, Cultured; Cyclosporine; Drug Combinations; Immunosuppressive Agents; Kidney; Mice; Podocytes; Proteins; Proteinuria; Proteomics; Sirolimus; TOR Serine-Threonine Kinases

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

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

Gentamicin may cause acute kidney injury. The pathogenesis of gentamicin nephrotoxicity is unclear. Autophagy is a highly conserved physiological process involved in removing damaged or aged biological macromolecules and organelles from the cytoplasm. The role of autophagy in the pathogenesis of gentamicin nephrotoxicity is unclear. The miniature pigs are more similar to humans than are those of rodents, and thus they are more suitable as human disease models. Here we established the first gentamicin nephrotoxicity model in miniature pigs, investigated the role of autophagy in gentamicin-induced acute kidney injury, and determined the prevention potential of rapamycin against gentamicin-induced oxidative stress and renal dysfunction. At 0, 1, 3, 5, 7 and 10 days after gentamicin administration, changes in autophagy, oxidative damage, apoptosis and inflammation were assessed in the model group. Compared to the 0-day group, gentamicin administration caused marked nephrotoxicity in the 10-day group. In the kidneys of the 10-day group, the level of autophagy decreased, and oxidative damage and apoptosis were aggravated. After rapamycin intervention, autophagy activity was activated, renal damage in proximal tubules was markedly alleviated, and interstitium infiltration of inflammatory cells was decreased. These results suggest that rapamycin may ameliorate gentamicin-induced nephrotoxicity by enhancing autophagy.

Topics: Acute Kidney Injury; Animals; Anti-Bacterial Agents; Apoptosis; Autophagy; Disease Models, Animal; Gentamicins; Inflammation; Kidney Tubules, Proximal; Microscopy, Electron, Transmission; Mitochondria; Oxidation-Reduction; Oxidative Stress; Protective Agents; Sirolimus; Swine; Swine, Miniature

Cardiovascular disease is the most common cause of sickness and death for long-term kidney transplant recipients, and dyslipidemia is an important risk factor for developing cardiovascular disease. Lipid-lowering strategies, with the use of statins, have been shown to reduce the cardiovascular risks related to dyslipidemia, but concomitant use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and immunosuppressive agents may increase the risk of rhabdomyolysis owing to a drug-drug interaction. We report a case of simvastatin-induced rhabdomyolysis and acute kidney injury triggered by addition of sirolimus and cisplatin-based chemotherapy to a kidney transplant recipient who had previously tolerated chronic statin therapy.

Topics: Acute Kidney Injury; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Drug Interactions; Dyslipidemias; Fatal Outcome; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Immunosuppressive Agents; Kidney Transplantation; Lung Neoplasms; Middle Aged; Renal Dialysis; Rhabdomyolysis; Risk Factors; Severity of Illness Index; Simvastatin; Sirolimus; Time Factors; Treatment Outcome

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

Everolimus, a mammalian target of Rapamycin inhibitor, has recently been approved for the treatment of metastatic estrogen receptor-positive breast cancer, in combination with exemestane at a daily dose of 10mg. In the literature, few cases of acute kidney injury have been reported related to everolimus use, but none of them in a patient with breast cancer as we report here. Our case report of acute kidney injury demonstrates the potential nephrotoxic effects of everolimus therapy, necessitating close monitoring of renal function prior to, during and after discontinuation of the drug.. We report the first published case of acute kidney injury shortly after initiation of exemestane and everolimus for metastatic breast cancer resistant to letrozole in a 69-year-old Caucasian woman, initially treated for a stage IIB estrogen receptor-positive breast cancer in 1997. Within 2 weeks of therapy, she developed grade 1 to 2 diarrhea, lower extremity edema, lethargy, and anorexia. After 4 weeks of therapy, her blood pressure was 85/59 mmHg and she lost 4 kg bodyweight. Her serum creatinine was 3.34 mg/dL. Everolimus was stopped, and she was hospitalized for rehydration. Her serum creatinine levels peaked at 8.85 mg/dL 8 days after treatment discontinuation, with a calculated creatinine clearance of 7 mL/minute. Dialysis was not required. A month later, her serum creatinine levels slowly dropped to 2.26 mg/dL but did not return to baseline. No re-challenge of everolimus was attempted.. Extreme vigilance should be used when prescribing everolimus for metastatic breast cancer. Although the exact cause of acute kidney injury in our case is unknown, dehydration must be avoided and renal function closely monitored after initiating therapy. Spontaneous recovery after drug discontinuation is possible.

Topics: Acute Kidney Injury; Aged; Androstadienes; Antineoplastic Agents; Breast Neoplasms; Creatinine; Drug Therapy, Combination; Everolimus; Female; Humans; Sirolimus

Everolimus was recently introduced as a second-line treatment for renal cell carcinoma (RCC) and many other cancers. Several prospective studies have shown that serum creatinine levels are increased in a significant proportion of patients receiving everolimus. However, data on the occurrence of acute kidney injury (AKI) during everolimus treatment in clinical practice are sparse. Here, we report the incidence, risk factors, and clinical significance of AKI associated with everolimus treatment in patients with cancer.. We analyzed patients who received everolimus for more than 4 weeks as an anticancer therapy. AKI was defined as increase in creatinine levels from baseline levels greater than 1.5-fold.. The majority of the 110 patients enrolled in this analysis had RCC (N=93, 84.5%). AKI developed in 21 (23%) RCC patients; none of the patients (N=17) with other cancers had AKI. Fourteen of 21 cases were considered to be everolimus-associated AKI, in which there were no other nephrotoxic insults other than everolimus at the onset of AKI. The incidence of AKI increased progressively as baseline estimated glomerular filtration rate (eGFR) decreased (10% in subjects with eGFR >90 mL/min/1.73 m2, 17% in subjects with eGFR 60-90 mL/min/1.73 m2, 28% in subjects with eGFR 30-60 mL/min/1.73 m2, and 100% in subjects with eGFR 15-30 mL/min/1.73 m2; P=0.029 for trend). Baseline eGFR was an independent risk factor for the development of everolimus-associated AKI (hazard ratio per 10 mL/min/1.73 m2 increase, 0.70; 95% confidential interval, 049-1.00; P=0.047). Nine of 14 patients with everolimus-associated AKI continued receiving the drug at a reduced dose or after a short-term off period. Administration of the drug was discontinued in four of 14 patients because of progression of an underlying malignancy. Only one patient stopped taking the drug because of AKI.. This paper suggests that AKI is a common adverse effect of everolimus treatment, especially in subjects with impaired renal function. However, the occurrence of AKI did not require the discontinuation of the drug, and the treatment decision should be made via a multidisciplinary approach, including the assessment of the oncological benefits of everolimus and other therapeutic options.

Topics: Acute Kidney Injury; Aged; Antineoplastic Agents; Carcinoma, Renal Cell; Creatinine; Everolimus; Female; Glomerular Filtration Rate; Humans; Incidence; Kidney Neoplasms; Male; Middle Aged; Risk Factors; Sirolimus

To determine that 1) an age-dependent loss of inducible autophagy underlies the failure to recover from AKI in older, adult animals during endotoxemia, and 2) pharmacologic induction of autophagy, even after established endotoxemia, is of therapeutic utility in facilitating renal recovery in aged mice.. Murine model of endotoxemia and cecal ligation and puncture (CLP) induced acute kidney injury (AKI).. Academic research laboratory.. C57Bl/6 mice of 8 (young) and 45 (adult) weeks of age.. Lipopolysaccharide (1.5 mg/kg), Temsirolimus (5 mg/kg), AICAR (100 mg/kg).. Herein we report that diminished autophagy underlies the failure to recover renal function in older adult mice utilizing a murine model of LPS-induced AKI. The administration of the mTOR inhibitor temsirolimus, even after established endotoxemia, induced autophagy and protected against the development of AKI.. These novel results demonstrate a role for autophagy in the context of LPS-induced AKI and support further investigation into like interventions that have potential to alter the natural history of disease.

Topics: Acute Kidney Injury; Aminoimidazole Carboxamide; Animals; Autophagy; Class III Phosphatidylinositol 3-Kinases; Endotoxemia; Lipopolysaccharides; Male; Mice; Protein Kinase Inhibitors; Ribonucleotides; Sirolimus; TOR Serine-Threonine Kinases

Recipients after liver transplantation. (OLT) often experience renal dysfunction. Acute kidney injury (AKI) and chronic kidney disease (CKD) after OLT occur among 20% to 50% and 30% to 90% of recipients, respectively; 2% to 5% of them deteriorate into end-stage renal disease each year. Since the predictable factors for CKD have not been well identified. We sought to investigate the incidence and predictors of CKD at 5 years after OLT.. Between August 2002 and December 2005, we enrolled 77 patients who underwent adult living donor OLT with over 2 years of follow-up. The strategies to prevent renal dysfunction included induction with basiliximab to delay the use of tacrolimus: addition of mycophenolate mofetil to reduce the tacrolimus dosage; avoidance of the calcineurin inhibitor using sirolimus or administration of an angiotensin II receptor antagonist. The clinical variables were reviewed for analysis.. The mean follow-up was 76 ± 14 months. The incidence of AKI (over 50% increase level of creatinine) was 29%. Ten (13.0%) patients developed CKD (creatinine > 2 mg/dL). One (1.3%) subject developed end-stage renal disease requiring hemodialysis. Upon multivariate analysis the development of CKD was significantly associated with the posttransplant 4-week creatinine level: 0.92 ± 0.23 versus 1.37 ± 0.93 mg/dL (P = .008).. The 4-week creatinine value was predictive of the occurence of CKD over 5 years after OLT.

Topics: Acute Kidney Injury; Adult; Angiotensin Receptor Antagonists; Antibodies, Monoclonal; Basiliximab; Creatinine; Female; Humans; Immunosuppressive Agents; Incidence; Kidney Failure, Chronic; Liver Transplantation; Living Donors; Male; Middle Aged; Mycophenolic Acid; Recombinant Fusion Proteins; Sirolimus; Tacrolimus

Topics: Abdominal Cavity; Acute Kidney Injury; Axitinib; Carcinoma, Renal Cell; Combined Modality Therapy; Everolimus; Humans; Imidazoles; Immunosuppressive Agents; Indazoles; Interferon-alpha; Kidney Neoplasms; Lymph Node Excision; Lymph Nodes; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Recurrence, Local; Neoplasm Staging; Nephrectomy; Protein Kinase Inhibitors; Remission Induction; Sirolimus; Tomography, X-Ray Computed; Withholding Treatment

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

Inhibitors of mammalian target of rapamycin (mTOR) have immunosuppressive and anti-cancer effects, but their effects on the progression of kidney disease are not fully understood. Using cells from normal kidney epithelial cell lines, we found that the antiproliferative effects of mTOR inhibitor everolimus accompanied the accumulation of a marker for cellular autophagic activity, the phosphatidylethanolamine-conjugated form of microtubule-associated protein 1 light chain 3 (LC3-II) in cells. We also showed that the primary autophagy factor UNC-51-like kinase 1 was involved in the antiproliferative effects of everolimus. Levels of LC3-II decreased in the kidneys of rats treated with ischemia-reperfusion or cisplatin; however, renal LC3-II levels increased after administration of everolimus to rats subjected to ischemia-reperfusion or cisplatin treatment. Simultaneously, increased signals for kidney injury molecule-1 and single-stranded DNA and decreased signals for Ki-67 in the proximal tubules were observed after treatment with everolimus, indicating that everolimus diminished renal function after acute tubular injury. We also found leakage of LC3 protein into rat urine after treatment with everolimus, and urinary LC3 protein was successfully measured between 0.1 and 500ng/mL by using an enzyme-linked immunosorbent assay. Urinary LC3 levels were increased after administration of everolimus to rats subjected to ischemia-reperfusion or cisplatin treatment, suggesting that renal LC3-II and urinary LC3 protein are new biomarkers for autophagy in acute kidney injury. Taken together, our results demonstrated that the induction of autophagy by everolimus aggravates tubular dysfunction during recovery from kidney injury.

Topics: Acute Kidney Injury; Animals; Autophagy; Biomarkers; Cell Line; Dogs; Everolimus; Humans; Immunosuppressive Agents; Kidney; Microtubule-Associated Proteins; Muscle, Skeletal; Rats; Rats, Wistar; Sirolimus; TOR Serine-Threonine Kinases

Topics: Acute Kidney Injury; Drug Interactions; Fatty Acids, Monounsaturated; Fluvastatin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Immunosuppressive Agents; Indoles; Kidney Transplantation; Rhabdomyolysis; Sirolimus

To evaluate the effects of sirolimus (SRL) on renal injury in rats with bile duct ligation.. A total of 21 male Sprague-Dawley rats weighing 220-260 g were used. Group 1 (Sham-control, n=7) rats were undergone laparotomy alone and bile duct was just dissected from the surrounding tissue. Group 2 rats (BDL/Untreated, n=7) were subjected to bile duct ligation and no drug was applied. Group 3 rats (BDL/SRL, n =7) received a daily dose of sirolimus (0.5 mg·day(-1) x kg(-1) dissolved 1 ml in saline) by orogastric tube for 14 days after BDL. At the end of the two-week period, biochemical and histological evaluation were processed.. AST, ALT, AP and TB levels values were decreased in group 3 when compared to group 2. There was no significant difference in serum levels of BUN and creatinine among all the experimental groups. Histological evaluation of the liver of BDL/Untreated group rats demonstrated marked portal fibrosis and signs of major bile duct obstruction with prominent portal and lobular inflammation. In BDL/SRL group, moderate damage was seen. Tubular injury scores were higher in the BDL subgroups; however, group 3 rats showed considerably fewer lesions in the tubules and interstitium compared to the group 2 rats. In group 2 animals, in the epithelial cells of proximal tubules presented vacuoles and hydropic changes, atrophy and inflammatory cell infiltrate in the medullar interstitium.. Sirolimus decreased tubulointerstitial lesions in kidney induced by bile duct ligation in rats. The improve effects of sirolimus on renal morphology can be due to improved liver function or due to direct action on the kidney.

Topics: Acute Kidney Injury; Animals; Bile Ducts; Disease Models, Animal; Kidney; Ligation; Male; Nephritis; Random Allocation; Rats; Rats, Sprague-Dawley; Sirolimus

Topics: Acute Kidney Injury; Antineoplastic Agents; Carcinoma; Humans; Kidney Neoplasms; Male; Middle Aged; Sirolimus

Topics: Acidosis, Renal Tubular; Acute Kidney Injury; Drug Therapy, Combination; Glomerular Filtration Rate; Hepatitis C, Chronic; HIV Infections; HIV Integrase Inhibitors; Humans; Immunosuppressive Agents; Liver Transplantation; Male; Middle Aged; Pyrrolidinones; Raltegravir Potassium; Sirolimus

Topics: Acute Kidney Injury; Adult; Biopsy; Humans; Immunosuppressive Agents; Liver Transplantation; Male; Sirolimus

We reported that rapamycin impairs recovery after acute renal failure (ARF) in rats. The objective of this study was to determine if recovery will eventually occur after ARF despite continued rapamycin treatment.. ARF was induced in rats by renal artery occlusion. Glomerular filtration rate (GFR), morphology, and tubular cell proliferation were assessed either 2, 4, 6, or 7 days later. Rats were treated daily with rapamycin or vehicle throughout the study. Cultured mouse proximal tubular (MPT) cells were used to compare the antiproliferative effects of rapamycin after exposure for 1 and 7 days.. Two days after ARF, GFR was reduced severely but comparably in vehicle and rapamycin rats. In controls, GFR began to increase after day 2 and was normal by day 6. In rapamycin rats, GFR did begin to improve until after day 4 and reached normal values by day 7. In controls, many proliferating tubular cells were present in outer medulla on day 2, after which proliferation progressively decreased. By contrast, in rapamycin rats, proliferating cells were sparse on day 2, but then increased substantially through days 4 and 6. Cultured MPT cells exposed to rapamycin for 7 days were approximately 10-fold more resistant to the antiproliferative effects of rapamycin than cells exposed for 1 day.. Rapamycin delays but does not prevent renal recovery after ARF. MPT cells become resistant to rapamycin after prolonged exposure. We speculate that the ultimate recovery of renal function after ARF is due to the development of acquired tubular cell resistance to rapamycin.

Topics: Acute Kidney Injury; Animals; Cell Proliferation; Drug Resistance; Glomerular Filtration Rate; Immunosuppressive Agents; Kidney Tubules, Proximal; Male; Mice; Rats; Rats, Sprague-Dawley; Recovery of Function; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus

Topics: Acute Kidney Injury; Adult; Coronary Angiography; Coronary Thrombosis; Creatinine; Cyclosporine; Electrocardiography; Endomyocardial Fibrosis; Graft Rejection; Heart Transplantation; Humans; Immunosuppressive Agents; Male; Shock, Cardiogenic; Sirolimus

Since using an immunosuppression regimen that includes rapamycin, we have occasionally encountered renal transplant patients who develop unexpected severe acute renal dysfunction. Biopsies obtained in these recipients demonstrate acute tubular necrosis (ATN) occasionally associated with tubular casts giving the classic appearance of myoglobin casts.. We retrospectively reviewed all biopsies from consecutively transplanted kidneys engrafted between April 9, 2002 and June 29, 2004 to determine the incidence of ATN, ATN with intratubular casts, and casts with the classic myoglobin appearance. The clinical setting, treatment, and outcomes of those patients with classic myoglobin-appearing casts are reviewed.. Histological ATN as the principal finding in at least one biopsy occurred in 10.5% (57/543) of patients. About half of these patients (30/57) had tubular casts present in at least one biopsy and in 14 of these the casts had a classic appearance of myoglobin casts. These myoglobin-appearing casts were only noted in patients receiving rapamycin. A review of 28 ATN biopsies from an earlier prerapamycin era did not demonstrate similar myoglobin-appearing casts. Immunostaining for myoglobin was positive in all 14 recipient biopsies. This was confirmed by western blot analyses in three of five patient biopsies tested. Three of three recipients tested had elevated serum creatine phosphokinase levels and detectable serum myoglobin. All 14 patients slowly resolved their acute renal dysfunction and no grafts were lost.. We conclude that myoglobinuria with myoglobin cast formation can occur following rapamycin administration, and may be a causative factor in the development of unexpected severe acute renal dysfunction.

Topics: Acute Kidney Injury; Biopsy; Humans; Immunoblotting; Immunosuppressive Agents; Incidence; Kidney Transplantation; Kidney Tubules; Myoglobin; Pancreas Transplantation; Retrospective Studies; Sirolimus

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

Severe leptospirosis manifestations include acute renal failure, caused by acute interstitial nephritis and pulmonary hemorrohage. Spirochete invasion and toxicity of outer membrane cause robust inflammatory host responses. These responses lead to the generation of cytokines, chemokines, and inflammatory cell infiltrations which result in severe organ dysfunctions. The immunomodulation by the modulation of host immune response may alleviate the renal and pulmonary injury. The authors determined whether the current immunosuppressive agents could alleviate the inflammation and minimize the organ injury in hamster model.. The animal experiments were conducted with the approval of The Ethical Research Committee of Chulalongkorn University Hospital. The leptospira interrogan serovar pyrogenese was isolated from a wild rat. The spirochete was grown in Fletcher's semisolid media and after subcultures were transferred to the Fletcher's liquid media. An amount of 0.5 ml of the spirochete culture media containing 1 x 10(8) leptospires/ml was intraperitoneally injected to golden Syrian hamsters (Mesocrietus auratus), age 4-6 weeks, weighing 60-80 grams. The hamsters were randomed into 5 groups (n = 4 in each group) namely, 1) Normal group (Control group), 2) Leptospira group, 3) CsA group (leptospira with cyclosporine feeding, 100 mg/kg/ day), 4) Rapa group (leptospira with rapamicin feeding, 0.6 mg/kg/day), and 5) Irra group (leptospira with irradiation). Cyclosporine and rapamicin were started at day 0 after the spirochete injection. Gamma ray dose 200 cGy was irradiated to the hamster 3 days before the spirochete inoculation. The animals were autopsied or euthanized if expired or at day 5 post inoculation. The blood samples for BUN, and creatinine were drawn before the inoculation and at autopsy or euthanasia.. The inoculation of L Interrogan 0.5 ml (1 x 10(8) leptospires/ml) without immunomodulation cause mortality of all animals at day 4 or day 5 post inoculation. The blood chemistry showed acute severe azotemia. The autopsy findings revealed severe interstitial nephritis and severe pulmonary hemorrhage. The hamsters in the Rapa group had only minimal pulmonary hemorrhage and minimal focal interstitial inflammation of kidney. There were cytoadherance of inflammatory cells to the endothelial cells in lungs and kidneys without the intrusion into the interstitium. The blood chemistry in Rapa group showed mild elevation of BUN and Cr. The immunomodulation by cyclosporine and irradiation did not alleviate the disease. On the contrary, cyclosporine and irradiation caused more severe histopathology.. The immunomodulation by rapamicin in leptospirosis in hamsters could alleviate the kidney and pulmonary injuries. The up-regulation of IL-2 in peripheral blood lymphocytes did not result in the kidney and pulmonary injuries.

Topics: Acute Kidney Injury; Animals; Cricetinae; Disease Models, Animal; Immunosuppressive Agents; Kidney; Leptospira; Leptospirosis; Lung; Sirolimus

Rapamycin (sirolimus) is associated with functional nephrotoxicity in some patients with nephrotic glomerular diseases but the pathophysiologic mechanisms are not known. This study investigated the effects of rapamycin on renal function and structure in protein overload nephropathy.. Rats with protein overload nephropathy [induced by bovine serum albumin (BSA), 2.1 g by daily intraperitoneal injection, day 0 to day 3] received daily intraperitoneal injections of either vehicle [dimethyl sulfoxide (DMSO)], rapamycin (0.2 mg/kg, an inhibitor of mammalian target of rapamycin), or roscovitine (3.5 mg/kg, a small molecule cyclin-dependent kinase inhibitor) (N= 9 each) from day -3 to day 3.. In protein overload nephropathy, rapamycin caused severe acute renal failure and mild hypercholesterolemia (both P < 0.05). Rapamycin dramatically increased intratubular cast formation, and proximal tubular epithelial cells were swollen and engorged with increased cytoplasmic protein droplets. The number of 5-bromo-2'-deoxyuridine (BrdU)-positive tubular epithelial cells increased by more than 20-fold on day 3 in protein overload nephropathy, and this was attenuated by 65% with rapamycin (P < 0.05), whereas roscovitine was ineffective. Rapamycin increased the protein expression of p27(kip1) in tubular epithelial cells, but did not alter D-type cyclin expression or apoptosis.. Rapamycin caused a specific pattern of acute renal injury characterized by increased intratubular cast formation in protein overload nephropathy. This could be due to disruption of a potentially important compensatory mechanism in nephrotic glomerular diseases involving tubular epithelial cell protein endocytosis and proliferation.

Topics: Acute Kidney Injury; Animals; Apoptosis; Cell Division; Cyclin D1; Cyclin D3; Cyclin-Dependent Kinase Inhibitor p27; Cyclins; Cytoplasm; Epithelial Cells; Female; Growth Inhibitors; Immunosuppressive Agents; Kidney Cortex; Kidney Tubules; Monocytes; Proteinuria; Purines; Rats; Rats, Wistar; Roscovitine; Serum Albumin, Bovine; Sirolimus

Recently observations of rhabdomyolysis in patients treated with tacrolimus have been reported. The authors present a kidney transplant patient who had an epileptic seizures, severe rhabdomyolysis, and acute renal failure. The patient was initially immunosuppressed with tacrolimus and chimeric CD25 monoclonal antibody. After intensive therapy with plasmapheresis, CVVH, and dialysis, the patient completely recovered at 11/2 year his serum creatinine is 1.2 mg/dL.

Topics: Acute Kidney Injury; Adolescent; Antibodies, Monoclonal; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Receptors, Interleukin-2; Renal Dialysis; Rhabdomyolysis; Sirolimus; Tacrolimus; Treatment Outcome

We began a clinical trial in African Americans comparing sirolimus-tacrolimus to standard immunosuppression. We report two African American male living donor kidney recipients who developed acute renal failure after exposure to sirolimus-tacrolimus.. Both patients received similar doses of sirolimus and tacrolimus to achieve target levels of 5 to 15 ng/mL and prednisone in tapering doses. Renal function and tacrolimus and sirolimus levels were systematically monitored.. Although both kidneys functioned immediately, acute oliguric renal failure developed approximately 2 weeks after transplantation. Transplant kidney biopsy showed acute tubular necrosis in patient 2. Sirolimus-tacrolimus was then stopped in both patients. Both patients required temporary hemodialysis. Renal function returned 2 weeks later and was normal 2 months after transplantation on tacrolimus plus mycophenolate mofetil.. Combination sirolimus-tacrolimus may cause nephrotoxicity in some patients by mechanisms that are presently unexplained.

Topics: Acute Kidney Injury; Adult; Humans; Immunosuppressive Agents; Kidney Transplantation; Living Donors; Male; Middle Aged; Sirolimus; Tacrolimus; Transplantation, Homologous

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

Advances in surgical techniques, postoperative care, and experience have led to improved outcome in heart transplant patients. Specifically, the use of corticosteroid-free immunosuppression has reduced the risk of infection. The use of pravastatin early after transplantation has led to a decrease in clinically severe rejection episodes, improvement in survival, and reduction in transplant coronary artery disease. Reduction in natural-killer-cell cytotoxicity in the pravastatin-treated patients suggests an adjunct immunosuppressive effect of pravastatin in those patients on CyA-based immunosuppression. Quality of life has also improved in the heart transplant recipient with cardiac rehabilitation demonstrating a beneficial role in the improvement of exercise capacity. Newer immunosuppressive agents and strategies continue to demonstrate benefit in improving survival and the quality of life of the heart transplant recipient.

Topics: Acute Kidney Injury; Antibodies, Monoclonal; Denervation; Graft Rejection; Heart; Heart Transplantation; Humans; Immunosuppression Therapy; Mycophenolic Acid; Postoperative Care; Postoperative Complications; Quality of Life; Sirolimus; Tacrolimus; Ventricular Dysfunction, Right