Browsing by Subject "Reperfusion injury"

Now showing 1 - 4 of 4
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    Hepatic Ischemia/Reperfusion Injury After Liver Transplantation Is Not Associated with Early Impairment of Left Ventricular Ejection Fraction
    (International Scientific Information, 2022-12-13) Rokop, Zachary P.; Frick, Kyle; Zenisek, Joseph; Kroepfl, Elizabeth; Mihaylov, Plamen; Patidar, Kavish R.; Nephew, Lauren; Mangus, Richard S.; Kubal, Chandrashekhar; Surgery, School of Medicine
    Background: Early myocardial dysfunction is a known complication following liver transplant. Although hepatic ischemia/reperfusion injury (hIRI) has been shown to cause myocardial injury in rat and porcine models, the clinical association between hIRI and early myocardial dysfunction in humans has not yet been established. We sought to define this relationship through cardiac evaluation via transthoracic echocardiography (TTE) on postoperative day (POD) 1 in adult liver transplant recipients. Material/Methods: TTE was performed on POD1 in all liver transplant patients transplanted between January 2020 and April 2021. Hepatic IRI was stratified by serum AST levels on POD1 (none: <200; mild: 200–2000; moderate: 2000–5000; severe: >5000). All patients had pre-transplant TTE as part of the transplant evaluation. Results: A total of 173 patients underwent liver transplant (LT) between 2020 and 2021 and had a TTE on POD 1 (median time to echo: 1 day). hIRI was present in 142 (82%) patients (69% mild, 8.6% moderate, 4% severe). Paired analysis between pre-LT and post-LT left ventricular ejection fraction (LVEF) of the entire study population demonstrated no significant decrease following LT (mean difference: −1.376%, P=0.08). There were no significant differences in post-LT LVEF when patients were stratified by severity of hIRI. Three patients (1.7%) had significant post-transplant impairment of LVEF (<35%). None of these patients had significant hIRI. Conclusions: hIRI after liver transplantation is not associated with immediate reduction in LVEF. The pathophysiology of post-LT cardiomyopathy may be driven by extra-hepatic triggers.
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    Human extracellular microvesicles from renal tubules reverse kidney ischemia-reperfusion injury in rats
    (PLOS, 2018-08-27) Dominguez II, James M.; Dominguez, Jesus H.; Xie, Danhui; Kelly, Katherine J.; Medicine, School of Medicine
    Hypoxic acute kidney injury, a major unresolved problem, initiates, or aggravates, renal functional and structural decline. There is no treatment for hypoxic acute renal injury and its sequelae. We tested the hypothesis that human kidney tubular cells, or their extracellular vesicles (exosomes), prevent renal injury when infused intravenously 24 hours after 50 minutes of bilateral renal ischemia in Nude rats. Cells and their exosomes were from harvested human kidneys declined for transplantation. Injections of either cells or exosomes, given after 24 and 48 hours of reperfusion, preserved renal function and structure in both treatment groups. However, exosomes were superior to cells; and maintained renal vascular and epithelial networks, prevented renal oxidant stress, and apoptosis; and restrained activation of pro-inflammatory and pro-fibrogenic pathways. Exosomes worked in 24 hours, consistent with functional rather than regenerative activity. Comprehensive proteomic analysis identified 6152 renal proteins from all cellular compartments; and 628 were altered by ischemia at all cell levels, while 377 were significantly improved by exosome infusions. We conclude that renal damage from severe ischemia was broad, and human renal exosomes prevented most protein alterations. Thus, exosomes seem to acutely correct a critical and consequential abnormality during reperfusion. In their absence, renal structure and cells transition to a chronic state of fibrosis and extensive renal cell loss.
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    Interleukin-6 Therapy Improves Intestinal Recovery Following Ischemia
    (Elsevier, 2019-07) te Winkel, Jan P.; Drucker, Natalie A.; Morocho, Bryant S.; Shelley, W. Christopher; Markel, Troy A.; Surgery, School of Medicine
    Background: Interleukin-6 (IL6) has both proinflammatory and anti-inflammatory pathways, but its effects on intestinal recovery following ischemia are unknown. We hypothesized that administration of IL6 following intestinal ischemia would improve mesenteric perfusion and mucosal injury. Methods: Adult male C57Bl6J mice were anesthetized, and a laparotomy was performed. Baseline intestinal perfusion was assessed by laser Doppler imaging. Intestinal ischemia was induced for 60 min by temporarily occluding the superior mesenteric artery. After ischemia, treatments were administered intraperitoneally before closure (Vehicle: 250 μL phosphate-buffered-saline, IL6 low dose (20 ng), IL6 medium dose (200 ng), or IL6 high dose (2 μg)). Animals were allowed to recover for 24 h, were reanesthetized, and their mesenteric perfusion was reassessed. Perfusion was expressed as percentage of baseline. Animals were then sacrificed, and the intestines were explanted for histological analysis. Separate frozen samples were homogenized and analyzed by ELISA for vascular endothelial growth factor (VEGF) and interferon gamma-induced protein 10. Results: IL6 increased mesenteric perfusion in low dose groups only, whereas it improved postischemic mucosal injury scores in both low and medium dose groups. No differences in perfusion or histology were seen when high dose IL6 was utilized. Intestinal VEGF was higher in the low dose IL6 group compared to vehicle, whereas IP-10 levels were lower in low and medium dose groups compared to vehicle. No differences were noted compared to vehicle in intestinal VEGF and IP-10 with high dose IL6 therapy.
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    The Effects of Peroxisome Proliferator-Activated Receptor-Delta Modulator ASP1128 in Patients at Risk for Acute Kidney Injury Following Cardiac Surgery
    (Elsevier, 2023-04-08) van Till, J. W. Olivier; Nojima, Hiroyuki; Kameoka, Chisato; Hayashi, Chieri; Sakatani, Taishi; Washburn, T. Benton; Molitoris, Bruce A.; Shaw, Andrew D.; Engelman, Daniel T.; Kellum, John A.; Medicine, School of Medicine
    Introduction: Peroxisome proliferator-activated receptor δ (PPARδ) plays a central role in modulating mitochondrial function in ischemia-reperfusion injury. The novel PPARδ modulator, ASP1128, was evaluated. Methods: A randomized, double-blind, placebo-controlled, biomarker assignment-driven, multicenter study was performed in adult patients at risk for acute kidney injury (AKI) following cardiac surgery, examining efficacy and safety of a 3-day, once-daily intravenous dose of 100 mg ASP1128 versus placebo (1:1). AKI risk was based on clinical characteristics and postoperative urinary biomarker (TIMP2)•(IGFBP7). The primary end point was the proportion of patients with AKI based on serum creatinine within 72 hours postsurgery (AKI-SCr72h). Secondary endpoints included the composite end point of major adverse kidney events (MAKE: death, renal replacement therapy, and/or ≥25% reduction of estimated glomerular filtration rate [eGFR]) at days 30 and 90). Results: A total of 150 patients were randomized and received study medication (81 placebo, 69 ASP1128). Rates of AKI-SCr72h were 21.0% and 24.6% in the placebo and ASP1128 arms, respectively (P = 0.595). Rates of moderate/severe AKI (stage 2/3 AKI-SCr and/or stage 3 AKI-urinary output criteria) within 72 hours postsurgery were 19.8% and 23.2%, respectively (P = 0.609). MAKE occurred within 30 days in 11.1% and 13.0% in the placebo and ASP1128 arms (P = 0.717), respectively; and within 90 days in 9.9% and 15.9% in the placebo and ASP1128 arms (P = 0.266), respectively. No safety issues were identified with ASP1128 treatment, but rates of postoperative atrial fibrillation were lower (11.6%) than in the placebo group (29.6%). Conclusion: ASP1128 was safe and well-tolerated in patients at risk for AKI following cardiac surgery, but it did not show efficacy in renal endpoints.