Adiponectin ameliorates lung ischemia-reperfusion injury through SIRT1-PINK1 signaling-mediated mitophagy in type 2 diabetic rats.

BACKGROUND: Diabetes mellitus (DM) is a key contributing factor to poor survival in lung transplantation recipients. Mitochondrial dysfunction is recognized as a critical mediator in the pathogenesis of diabetic lung ischemia-reperfusion (IR) injury. The protective effects of adiponectin have been demonstrated in our previous study, but the underlying mechanism remains unclear. Here we demonstrated an important role of mitophagy in the protective effect of adiponectin during diabetic lung IR injury. METHODS: High-fat diet-fed streptozotocin-induced type 2 diabetic rats were exposed to adiponectin with or without administration of the SIRT1 inhibitor EX527 following lung transplantation. To determine the mechanisms underlying the action of adiponectin, rat pulmonary microvascular endothelial cells were transfected with SIRT1 small-interfering RNA or PINK1 small-interfering RNA and then subjected to in vitro diabetic lung IR injury. RESULTS: Mitophagy was impaired in diabetic lungs subjected to IR injury, which was accompanied by increased oxidative stress, inflammation, apoptosis, and mitochondrial dysfunction. Adiponectin induced mitophagy and attenuated subsequent diabetic lung IR injury by improving lung functional recovery, suppressing oxidative damage, diminishing inflammation, decreasing cell apoptosis, and preserving mitochondrial function. However, either administration of 3-methyladenine (3-MA), an autophagy antagonist or knockdown of PINK1 reduced the protective action of adiponectin. Furthermore, we demonstrated that APN affected PINK1 stabilization via the SIRT1 signaling pathway, and knockdown of SIRT1 suppressed PINK1 expression and compromised the protective effect of adiponectin. CONCLUSION: These data demonstrated that adiponectin attenuated reperfusion-induced oxidative stress, inflammation, apoptosis and mitochondrial dysfunction via activation of SIRT1- PINK1 signaling-mediated mitophagy in diabetic lung IR injury.

Hydrogen Sulfide Ameliorates Lung Ischemia-Reperfusion Injury Through SIRT1 Signaling Pathway in Type 2 Diabetic Rats.

Lung ischemia-reperfusion (IR) injury remains a significant factor for the early mortality of lung transplantations. Diabetes mellitus (DM) is an independent risk factor for 5-year mortality following lung transplantation. Our previous study showed that DM aggravated lung IR injury and that oxidative stress played a key role in this process. Previously, we demonstrated that hydrogen sulfide (H2S) protected against diabetic lung IR injury by suppressing oxidative damage. This study aimed to examine the mechanism by which H2S affects diabetic lung IR injury. High-fat-diet-fed streptozotocin-induced type 2 diabetic rats were exposed to GYY4137, a slow-releasing H2S donor with or without administration of EX527 (a SIRT1 inhibitor), and then subjected to a surgical model of IR injury of the lung. Lung function, oxidative stress, cell apoptosis, and inflammation were assessed. We found that impairment of lung SIRT1 signaling under type 2 diabetic conditions was further exacerbated by IR injury. GYY4137 treatment markedly activated SIRT1 signaling and ameliorated lung IR injury in type 2 DM animals by improving lung functional recovery, diminishing oxidative damage, reducing inflammation, and suppressing cell apoptosis. However, these effects were largely compromised by EX527. Additionally, treatment with GYY4137 significantly activated the Nrf2/HO-1 antioxidant signaling pathway and increased eNOS phosphorylation. However, these effects were largely abolished by EX527. Together, our results indicate that GYY4137 treatment effectively attenuated lung IR injury under type 2 diabetic conditions via activation of lung SIRT1 signaling. SIRT1 activation upregulated Nrf2/HO-1 and activated the eNOS-mediated antioxidant signaling pathway, thus reducing cell apoptosis and inflammation and eventually preserving lung function.

Hydrogen sulfide attenuates lung ischemia-reperfusion injury through SIRT3-dependent regulation of mitochondrial function in type 2 diabetic rats.

BACKGROUND: Lung ischemia-reperfusion injury is a complex pathophysiologic process associated with high morbidity and mortality. We have demonstrated elsewhere that diabetes mellitus aggravated ischemia-induced lung injury. Oxidative stress and mitochondrial dysfunction are drivers of diabetic lung ischemia-reperfusion injury; however, the pathways that mediate these events are unexplored. In this study using a high-fat diet-fed model of streptozotocin-induced type 2 diabetes in rats, we determined the effect of hydrogen sulfide on lung ischemia-reperfusion injury with a focus on Sirtuin3 signaling. METHODS: Rats with type 2 diabetes were exposed to GYY4137, a slow release donor of hydrogen sulfide with or without administration of the Sirtuin3 short hairpin ribonucleic acid plasmid, and then subjected to a surgical model of ischemia-reperfusion injury of the lung (n = 8). Lung function, oxidative stress, inflammation, cell apoptosis, and mitochondrial function were measured. RESULTS: Compared with nondiabetic rats, animals with type 2 diabetes at baseline exhibited significantly decreased Sirtuin3 signaling in lung tissue and increased oxidative stress, apoptosis, inflammation, and mitochondrial dysfunction (P < .05 each). In addition, further impairment in Sirtuin3 signaling was found in diabetic rats subjected to this model of lung ischemia-reperfusion. Simultaneously, the indexes showed further aggravation. Treatment with hydrogen sulfide restored Sirtuin3 expression and decreased lung ischemia-reperfusion injury in animals with type 2 diabetes mellitus by improving lung functional recovery, decreasing oxidative damage, suppressing inflammation, ameliorating cell apoptosis, and preserving mitochondrial function (P < .05). Conversely, these protective effects were largely reversed in Sirtuin3 knockdown rats. CONCLUSION: Impaired lung Sirtuin3 signaling associated with type 2 diabetic conditions was further attenuated by an ischemia-reperfusion insult. Hydrogen sulfide ameliorated reperfusion-induced oxidative stress and mitochondrial dysfunction via activation of Sirtuin3 signaling, thereby decreasing lung ischemia-reperfusion damage in rats with a model of type II diabetes.

Effect of preoperative inhaled budesonide on pulmonary injury after cardiopulmonary bypass: A randomized pilot study.

BACKGROUND: Cardiopulmonary bypass can result in lung injury. This prospective, double-blinded, randomized trial aimed to evaluate the protective effect of inhaled budesonide on lung injury after cardiopulmonary bypass. METHODS: Sixty patients, aged 25 to 65 years, requiring cardiopulmonary bypass were randomized to groups treated with saline or budesonide inhalation preoperatively. The respiratory mechanics were recorded. Bronchoalveolar lavage fluid was collected before cardiopulmonary bypass and after sternal closure. Serum and bronchoalveolar lavage fluid levels of proinflammatory and anti-inflammatory factors were analyzed. The primary end point was the lowest ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen after cardiopulmonary bypass. The durations of ventilation and postoperative recovery time were noted. RESULTS: Budesonide significantly improved respiratory mechanics after cardiopulmonary bypass. Budesonide improved the partial pressure of arterial oxygen to the fraction of inspired oxygen ratio from 8 to 48 hours after the operation. Budesonide shortened the durations of mechanical ventilation and postoperative recovery time. Budesonide decreased the levels of proinflammatory factors while increasing the levels of anti-inflammatory factors in bronchoalveolar lavage fluid and serum (all P < .05). The macrophage and neutrophil counts, and protein and elastase concentrations were decreased by budesonide treatment. CONCLUSIONS: Budesonide treatment shortened the durations of mechanical ventilation, inhibited local and systemic inflammation, and improved respiratory function after cardiopulmonary bypass.

Epidural Co-Administration of Dexmedetomidine and Levobupivacaine Improves the Gastrointestinal Motility Function after Colonic Resection in Comparison to Co-Administration of Morphine and Levobupivacaine.

UNLABELLED: Gastrointestinal motility may be impaired after intestinal surgery. Epidural morphine is effective in controlling postoperative pain, but can further reduce gastrointestinal motility. Here, we aimed to investigate the effects of epidural dexmedetomidine on gastrointestinal motility in patients undergoing colonic resection. Seventy-four patients undergoing colonic resection were enrolled in this clinical trial and allocated randomly to treatment with dexmedetomidine (D group) or morphine (M group). The D group received a loading dose epidural administration of 3 ml dexmedetomidine (0.5 µg kg(-1)) and then a continuous epidural administration of 80 µg dexmedetomidine in 150 ml levobupivacaine (0.125%) at 3 ml h(-1) for two days. The M group received a loading dose epidural administration of 3 ml morphine (0.03 mg kg(-1)) and then a continuous epidural administration of 4.5 mg morphine in 150 ml levobupivacaine at 3 ml h(-1) for two days. Verbal rating score (VRS), postoperative analgesic requirements, side effects related to analgesia, the time to postoperative first flatus (FFL) and first feces (FFE) were recorded. VRS and postoperative analgesic requirements were not significantly different between treatment groups. In contrast, the time to FFL and time to FFE were significant longer in M group in comparison to D group (P < 0.05). Moreover, patients in M group had a significantly higher incidence of nausea, vomiting, and pruritus (P < 0.05). No patients showed neurologic deficits in either group. In comparison to morphine, epidural dexmedetomidine is safe and beneficial for the recovery of gastrointestinal motility after colonic resection when used as an adjunct with levobupivacaine for postoperative pain control. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-TRC-14004644.

MAPK mediates inflammatory response and cell death in rat pulmonary microvascular endothelial cells in an ischemia-reperfusion model of lung transplantation.

BACKGROUND: Hypoxia-reoxygenation of cultured macrovascular endothelial cells is used to study ischemia-reperfusion (IR)-related cellular and molecular changes; however, these models do not accurately depict events in pulmonary microvascular endothelial cells (PMVECs) during conventional lung retrieval and transplantation. We used rat PMVECs in a new non-hypoxic cell-based lung transplantation model to assess these events. METHODS: To simulate cold storage, rat PMVECs were preserved in 95% O2-5% CO2 at 4°C for 6 hours in low-potassium dextran solution. Dishes were warmed for 1 hour to room temperature for simulating implantation. Medium was added at 37°C in 50% O2-5% CO2-45% N2 to simulate reperfusion. Additional PMVECs were transfected with siRNA targeting mitogen-activated protein kinases (MAPKs) and then subjected to simulated IR. RESULTS: MAPKs and NF-κB were activated during simulated reperfusion, and AP-1 was activated during ischemia and reperfusion. Increased malondialdehyde levels were found during cold ischemia, and apoptosis and production of IL-1ß, IL-6, and TNF-α were observed during reperfusion. Silencing of MAPKs attenuated oxidative stress, inflammation and apoptosis. Silencing of JNK and p38 decreased NF-κB phosphorylation and increased inhibitor of NF-κB (IκB)α levels. Knockdown of ERK1/2 increased NF-κB phosphorylation but had no effect on IκBα expression. Silencing of JNK and ERK1/2, but not p38, decreased AP-1 phosphorylation. CONCLUSIONS: Exposing rat PMVECs to simulated non-hypoxic IR caused lipid peroxidation, inflammation and apoptosis, which required MAPK-mediated NF-κB and AP-1 activation and distinct regulation of MAPKs by these 2 transcription factors. This model could be used to uncouple mechanisms of IR and evaluate potential therapeutics in alleviating IR injury.

Intratracheal administration of p38α short-hairpin RNA plasmid ameliorates lung ischemia-reperfusion injury in rats.

BACKGROUND: Lung ischemia-reperfusion injury (LIRI) remains a significant problem after lung transplantation. A crucial signaling enzyme involved in inflammation and apoptosis during LIRI is p38 mitogen-activated protein kinase (MAPK). Gene silencing of p38α by short hairpin RNA (shRNA) can downregulate p38α expression. The lungs have an extremely large surface area, which makes the absorption of shRNA highly effective. Therefore, we evaluated the therapeutic efficacy of p38α shRNA plasmids in a rat model of lung transplantation. METHODS: The delivery of p38α shRNA plasmid was performed by intratracheal administration 48 hours before transplantation into donor rats. Control animals received scrambled shRNA plasmids. Reverse-transcription polymerase chain reaction and Western blots were used to assess gene silencing efficacy. The therapeutic effects of shRNA plasmids were evaluated by lung function tests. We determined the levels of inflammatory cytokines, the level of intercellular adhesion molecule 1 (ICAM-1), c-Myc mRNA expression, and ICAM-1 protein expression, and the presence of cell apoptosis. RESULTS: Rats administered p38α shRNA plasmids showed a significant downregulation in lung expression of p38α transcripts and protein levels. Compared with the control group, the p38α shRNA group showed a higher pulmonary vein oxygen level, lower wet weight-to-dry weight ratio, lower lung injury score, and lower serum levels of tumor necrosis factor-α, interleukin-6, and interleukin-8. Messenger RNA levels of ICAM-1 and c-Myc in the p38α shRNA group were dramatically lower than in the control group. Levels of ICAM-1 protein expression exhibited a similar trend. Cell apoptosis decreased in the p38α shRNA group vs the control group. CONCLUSION: Intratracheal administration of p38α shRNA plasmids provided therapeutic effects in a rat model of lung transplantation.