sirolimus and Cerebral-Hemorrhage

Intracerebral hemorrhage (ICH) causes autophagy as well as inflammation; the latter is known to involve the high-mobility group box 1 protein (HMGB1)/Toll-like receptor 4 (TLR4) axis. Here we investigated whether this axis may help mediate both the autophagy and inflammation associated with ICH.. ICH was induced by injecting autologous blood into Sprague-Dawley rats, followed in some cases by intracerebroventricular injection of short interfering RNA (siRNA) against HMGB1 or TLR4 at 6 h after ICH induction or by intraperitoneal injection of the autophagy inhibitor 3-methyladenine (3-MA) or autophagy activator rapamycin at 6, 24, and 48 h after ICH induction. Western blotting, immunohistochemistry or immunofluorescence was used to assess levels of HMGB1/TLR4 signaling pathway proteins as well as markers of autophagy (LC3B, Beclin1, Atg5) or inflammation (IL-1 beta, TNF-α). Numbers of apoptotic cells were determined using TUNEL staining. Changes in levels of these proteins were correlated with neurological deficits measured using the modified Neurological Severity Score.. ICH caused HMGB1 to translocate from the nucleus into the cytoplasm, and it up-regulated expression of TLR4 and myeloid differentiation factor 88 (MyD88), and induced neurological deficits. Administering siRNA against HMGB1 or TLR4 reversed this up-regulation. Levels of markers of autophagy (LC3B, Beclin1, Atg5) or inflammation (IL-1 beta, TNF-α) were significantly higher 72 h after ICH than at baseline, as were the numbers of TUNEL-positive cells. Administering siRNA against HMGB1 or TLR4 markedly alleviated inflammation, and autophagy, apoptosis, and neurological deficits. Similarly, administering autophagy inhibitor 3-MA alleviated inflammation, apoptosis, and neurological deficits. Conversely, autophagy activator rapamycin exacerbated these effects of ICH.. During the acute phase of ICH, the HMGB1/TLR4/MyD88 axis acts via autophagy to promote inflammation.

Topics: Animals; Autophagy; Beclin-1; Cerebral Hemorrhage; HMGB1 Protein; Inflammation; Interleukin-1beta; Myeloid Differentiation Factor 88; Neuroinflammatory Diseases; Rats; Rats, Sprague-Dawley; RNA, Small Interfering; Sirolimus; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase and activation of its signal pathway plays an important role in regulating protein growth and synthesis as well as cell proliferation and survival. In the present study, we examined the contribution of mTOR signal and its downstream products to brain injuries induced by intracerebral hemorrhage (ICH) in rats.. Western Blot analysis was employed to examine the protein expression of mTOR and its downstream pathway and Caspase-3. ELISA was used to measure pro-inflammatory cytokines (PICs) and vascular endothelial growth factor (VEGF). Additionally, neurological Severity Score and brain water content were used to indicate neurological function and brain edema.. The protein expression of p-mTOR, mTOR-mediated phosphorylation of 4E-binding protein 4 (4E-BP1), p70 ribosomal S6 protein kinase 1 (S6K1) pathways were amplified in ICH rats compared with controls. Blocking mTOR using rapamycin significantly attenuated upregulation of PICs, namely IL-1β, IL-6 and TNF-α, and Caspase-3 indicating cell apoptosis, and promoted the levels of VEGF and its subtype receptor VEGFR-2 in brain tissues. Moreover, the effects of rapamycin were linked to improvement of neurological deficits and increased brain water content observed in ICH rats.. Activation mTOR signal is engaged in pathophysiological process during ICH and blocking mTOR pathway plays a beneficial role in regulating neuronal tissues via PIC, apoptotic Caspase-3 and VEGF mechanisms. This has pharmacological implications to target specific mTOR and its downstream signal pathway for neuronal dysfunction and vulnerability related to ICH.

Topics: Animals; Brain; Brain Edema; Carrier Proteins; Caspase 3; Cerebral Hemorrhage; Cytokines; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Intracellular Signaling Peptides and Proteins; Male; Phosphoproteins; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Up-Regulation; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

Intracerebral hemorrhage (ICH) results in a devastating brain disorder with high mortality and poor prognosis and effective therapeutic intervention for the disease remains a challenge at present. The present study investigated the neuroprotective effects of rapamycin on ICH-induced brain damage and the possible involvement of activated microglia. ICH was induced in rats by injection of type IV collagenase into striatum. Different dose of rapamycin was systemically administrated by intraperitoneal injection beginning at 1 h after ICH induction. Western blot analysis showed that ICH led to a long-lasting increase of phosphorylated mTOR and this hyperactivation of mTOR was reduced by systemic administration of rapamycin. Rapamycin treatment significantly improved the sensorimotor deficits induced by ICH, and attenuated ICH-induced brain edema formation as well as lesion volume. Nissl and Fluoro-Jade C staining demonstrated that administration with rapamycin remarkably decreased neuronal death surrounding the hematoma at 7 d after ICH insult. ELISA and real-time quantitative PCR demonstrated that rapamycin inhibited ICH-induced excessive expression of TNF-α and IL-1β in ipsilateral hemisphere. Furthermore, activation of microglia induced by ICH was significantly suppressed by rapamycin administration. These data indicated that treatment of rapamycin following ICH decreased the brain injuries and neuronal death at the peri-hematoma striatum, and increased neurological function, which associated with reduced the levels of proinflammatory cytokines and activated microglia. The results provide novel insight into the neuroprotective therapeutic strategy of rapamycin for ICH insult, which possibly involving the regulation of microglial activation.

Topics: Animals; Blotting, Western; Brain; Brain Edema; Cerebral Hemorrhage; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Gene Expression; Immunohistochemistry; Interleukin-1beta; Male; Microglia; Neurons; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha

This study examines the role of thrombin's protease-activated receptor (PAR)-1, PAR-4 in mediating cyclooxygenase-2 and mammalian target of rapamycin after germinal matrix hemorrhage.. Germinal matrix hemorrhage was induced by intraparenchymal infusion of bacterial collagenase into the right ganglionic eminence of P7 rat pups. Animals were treated with PAR-1, PAR-4, cyclooxygenase-2, or mammalian target of rapamycin inhibitors by 1 hour, and ≤5 days.. We found increased thrombin activity 6 to 24 hours after germinal matrix hemorrhage, and PAR-1, PAR-4, inhibition normalized cyclooxygenase-2, and mammalian target of rapamycin by 72 hours. Early treatment with NS398 or rapamycin substantially improved long-term outcomes in juvenile animals.. Suppressing early PAR signal transduction, and postnatal NS398 or rapamycin treatment, may help reduce germinal matrix hemorrhage severity in susceptible preterm infants.

Topics: Animals; Animals, Newborn; Anti-Inflammatory Agents, Non-Steroidal; Brain Injuries; Cerebral Hemorrhage; Cyclooxygenase 2; Immunosuppressive Agents; Nitrobenzenes; Rats; Receptor, PAR-1; Receptors, Thrombin; Signal Transduction; Sirolimus; Sulfonamides

Mammalian target of rapamycin (mTOR), a serine/threonine kinase, regulates many processes, including cell growth and the immune response. mTOR is also dysregulated in several neurological diseases, such as traumatic brain injury (TBI), stroke, and neurodegenerative disease. However, the role of mTOR in intracerebral hemorrhage (ICH) remains unexplored. The aims of our study were to determine whether inhibiting mTOR signaling could affect the outcome after ICH and to investigate the possible underlying mechanism.. A rat ICH model was induced by intracerebral injection of collagenase IV into the striatum, and mTOR activation was inhibited by administration of rapamycin. mTOR signaling activation was determined by western blotting. Neurobehavioral deficit after ICH was determined by a set of modified Neurological Severity Scores (mNSS). The levels of CD4+CD25+Foxp3+ regulatory T cells (Tregs) and cytokines were examined using flow cytometry and ELISA, respectively.. Our results demonstrated thatmTOR signaling was activated 30 minutes and returned to its basal level 1 day after ICH. Increased p-mTOR, which mean that mTOR signaling was activated, was predominantly located around the hematoma. Rapamycin treatment significantly improved the neurobehavioral deficit after ICH, increased the number of Tregs, increased levels of interleukin-10 and transforming growth factor-β and reduced interferon-γ both in peripheral blood and brain.. Our study suggests that mTOR improves ICH outcome and modulates immune response after ICH.

Topics: Animals; Blood Transfusion, Autologous; Cerebral Cortex; Cerebral Hemorrhage; Collagenases; Corpus Striatum; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Forkhead Transcription Factors; Gene Expression Regulation; Male; Nervous System Diseases; Rats; Rats, Sprague-Dawley; Signal Transduction; Sirolimus; T-Lymphocytes, Regulatory; Time Factors; TOR Serine-Threonine Kinases

The optimal duration of dual antiplatelet therapy (DAT) in patients undergoing intracoronary sirolimus-eluting stent implantation remains controversial.. To evaluate the clinical effects of long duration DAT in patients undergoing intracoronary sirolimus-eluting stent implantation in daily practice. In addition, to attempt to identify the optimal duration of DAT after implantation of a sirolimus-eluting stent.. We retrospectively report on 1293 consecutive patients who underwent successful intracoronary sirolimus-eluting stent implantation. We analyzed the cumulative incidence of stent thrombosis, non-fatal myocardial infarction (MI), death from cardiac causes, and the cumulative incidence of bleeding complications.. We compared the study end point in patients who received DAT for <6 months (n=1136) with that for patients who received DAT for >6 months (n=157). The median follow-up period was 1260 ± 462 days. Major bleeding occurred in 35 patients and intracranial hemorrhage in 8. In patients on DAT for >6 months, the incidence of any bleedings, major bleedings, and intracranial hemorrhage was significantly increased. On the other hand, there was no significant difference between the two groups in the risk of the primary end points (stent thrombosis, non-fatal MI, death from cardiac causes, death or MI).. Prolonged DAT for more than 6 months was not significantly more beneficial than aspirin monotherapy in reducing the risk of the occurrence of acute MI, stent thrombosis, and death, although it was associated with an increase in bleeding complications for low-risk patients.

Topics: Aged; Cerebral Hemorrhage; Coronary Vessels; Diabetes Complications; Drug-Eluting Stents; Female; Hemorrhage; Humans; Male; Myocardial Infarction; Platelet Aggregation Inhibitors; Prosthesis Implantation; Retrospective Studies; Sirolimus; Thrombosis; Time Factors

The long-term safety and efficacy of sirolimus-eluting stents (SES) remain uncertain in real practice in Japan.. We used a hospital-based cohort (n = 6,562) comprising all the new patients who had visited our hospital between 2004 and 2007 to investigate the mortality and morbidity after SES or bare-metal stent (BMS) implantation.. Of the total, coronary artery disease was observed in 822 patients (12.5%), and SES or BMS were implanted in 208 and 167 patients, respectively. Patients receiving SES more often had diabetes but less often presented with acute myocardial infarction (MI). Median follow-up periods were 815 and 894 days for SES and BMS, respectively (p = 0.305). Intravascular ultrasound (IVUS) was used at a high rate (> 90%) in both groups, and maximum pressure inflation for SES was high at approximately 18 atm. The unadjusted cumulative incidence of all-cause death and major adverse cardiac events (MACE) (cardiac death, MI or target vessel revascularization) at 2 years was 4.3% versus 7.2% (p = 0.233) and 16.3% versus 32.9% (p < 0.001), respectively. In multivariate analysis, all-cause mortality was similar between SES (hazard ratio [HR] 0.981, 95% confidence interval [CI] 0.366-2.632) and BMS, but SES significantly reduced MACE (HR 0.468, 95% CI 0.280-0.784). Definite stent thrombosis set by the Academic Research Consortium was not observed in either group, and the incidence of cerebral hemorrhage was 0.5% in SES and 1.2% in BMS, respectively (p = 0.588).. SES used in real-world settings appeared to be safe and significantly associated with a lower risk of adverse events at long-term follow up in Japan, especially utilizing a careful stent deployment technique including high-pressure inflation and IVUS use.

Topics: Aged; Anti-Bacterial Agents; Cerebral Hemorrhage; Cohort Studies; Coronary Artery Disease; Drug-Eluting Stents; Female; Follow-Up Studies; Humans; Japan; Male; Middle Aged; Multivariate Analysis; Proportional Hazards Models; Retrospective Studies; Risk Factors; Sirolimus; Stents; Thrombosis; Treatment Outcome