Search Results (48)

Background/Objectives: A novel treatment of absolute uterine factor infertility is uterus transplantation. In preparation for human surgery, autotransplantation was performed in a sheep model to assess ischemia-reperfusion injury of the uterine wall. Methods: Seven multiparous ewes underwent live-donor uterus autotransplantation; in six, the procedure was completed successfully. Tissue blocks of complete uterine wall, endometrium, and myometrium were obtained at four predefined time points: native (baseline), after 1 h of cold ischemia, after 30 min of warm ischemia, and after 30 min of reperfusion. Samples were analyzed by differential scanning calorimetry and routine hematoxylin–eosin histology. Results: Histology demonstrated preserved epithelial, glandular, and stromal structures, with only minimal, reversible changes that increased with the ischemic duration. Differential scanning calorimetry confirmed alterations in thermal stability: in the uterine wall and myometrium, the calorimetric enthalpy decreased from baseline (3.40 ± 0.53 J/g) to reperfusion (2.62 ± 0.22 J/g), indicating structural loosening; in contrast, the endometrium calorimetric enthalpy slightly increased, suggesting greater flexibility and less susceptibility to ischemia-reperfusion injury. Conclusions: In this preliminary study, differential scanning calorimetry proved to be an effective and sensitive method for detecting early structural alterations in the uterine wall that could negatively impact post-transplant function. Cold and warm ischemia did not cause irreversible damage within a two-hour time frame, supporting the feasibility of short-term preservation in uterus transplantation. The myometrium demonstrated more significant vulnerability than the endometrium, which highlights the necessity of protective strategies to preserve smooth muscle integrity during transplantation. Full article

Background: Optimizing organ preservation techniques is imperative in the face of donor kidney shortage and high waiting list mortality. Hypothermic machine perfusion (HMP) has emerged as an effective method to improve graft function post-transplantation, particularly for deceased donor kidneys, prone to ischemia reperfusion injury (IRI). The perfusion solution includes glucose to support kidney metabolism; however, its effect on mitochondrial function remains unclear. The present study investigated the effect of glucose supplementation during 24 h of oxygenated HMP on mitochondrial function in porcine kidneys. Methods: After 30 min of warm ischemia, porcine slaughterhouse kidneys were preserved for 24 h using HMP with one of the following three solutions: the standard HMP preservation solution, University of Wisconsin machine perfusion (UW-MP) solution, which contains glucose; the solution used for static cold storage, University of Wisconsin cold storage (UW-CS) solution, which lacks glucose; or the UW-CS supplemented with 10 mmol/L glucose. Tissue and perfusate samples were collected before, during, and after perfusion for further analysis. Results: ATP production, mitochondrial respiration, and oxidative stress markers were not significantly different between groups. Glucose was released into the perfusion solution even from kidneys without exogenous glucose supplementation in the perfusate. Conclusions: These results suggest that kidney mitochondrial respiration does not depend on the presence of glucose in the HMP perfusion solution at the start of perfusion, underscoring the need for further exploration of nutrient supplementation and mitochondrial function in organ preservation strategies. Full article

Background: Exercise can promote sustainable protection against cold and warm liver ischemia–reperfusion injury (IRI) and tumor metastases. We have shown that this protection is by the induction of hepatic mitochondrial biogenesis pathway. In this study, we hypothesize that ZLN005, a PGC-1α activator, can be utilized as an alternative therapeutic strategy. Methods: Eight-week-old mice were pretreated with ZLN005 and subjected to liver warm IRI. To establish a liver metastatic model, MC38 cancer cells (1 × 10⁶) were injected into the spleen, followed by splenectomy and liver IRI. Results: ZLN005-pretreated mice showed a significant decrease in IRI-induced tissue injury as measured by serum ALT/AST/LDH levels and tissue necrosis. ZLN005 pretreatment decreased ROS generation and cell apoptosis at the site of injury, with a significant decrease in serum pro-inflammatory cytokines, innate immune cells infiltration, and intrahepatic neutrophil extracellular trap (NET) formation. Moreover, mitochondrial mass was significantly upregulated in hepatocytes and maintained after IRI. This was confirmed in murine and human hepatocytes treated with ZLN005 in vitro under normoxic and hypoxic conditions. Additionally, ZLN005 preconditioning significantly attenuated tumor burden and increased the percentage of intratumoral cytotoxic T cells. Conclusions: Our study highlights the effective protection of ZLN005 pretreatment as a therapeutic alternative in terms of acute liver injury and tumor metastases. Full article

Donation after circulatory death (DCD) is a promising strategy for alleviating donor shortage in heart transplantation. Trehalose, an autophagy inducer, has been shown to be cardioprotective in an ischemia-reperfusion (IR) model; however, its role in IR injury in DCD remains unknown. In the present study, we evaluated the effects of trehalose on cardiomyocyte viability and autophagy activation in a DCD model. In the DCD model, cardiomyocytes (H9C2) were exposed to 1 h warm ischemia, 1 h cold ischemia, and 1 h reperfusion. Trehalose was administered before cold ischemia (preconditioning), during cold ischemia, or during reperfusion. Cell viability was measured using the Cell Counting Kit-8 after treatment with trehalose. Autophagy activation was evaluated by measuring autophagy flux using an autophagy inhibitor, chloroquine, and microtubule-associated protein 1A/1B light chain 3 B (LC3)-II by western blotting. Trehalose administered before the ischemic period (trehalose preconditioning) increased cell viability. The protective effects of trehalose preconditioning on cell viability were negated by chloroquine treatment. Furthermore, trehalose preconditioning increased autophagy flux. Trehalose preconditioning increased cardiomyocyte viability through the activation of autophagy in a DCD model, which could be a promising strategy for the prevention of cardiomyocyte damage in DCD transplantation. Full article

Heart transplantation with donation after circulatory death (DCD) provides excellent patient outcomes and increases donor heart availability. However, unlike conventional grafts obtained through donation after brain death, DCD cardiac grafts are not only exposed to warm, unprotected ischemia, but also to a potentially damaging pre-ischemic phase after withdrawal of life-sustaining therapy (WLST). In this review, we aim to bring together knowledge about changes in cardiac energy metabolism and its regulation that occur in DCD donors during WLST, circulatory arrest, and following the onset of warm ischemia. Acute metabolic, hemodynamic, and biochemical changes in the DCD donor expose hearts to high circulating catecholamines, hypoxia, and warm ischemia, all of which can negatively impact the heart. Further metabolic changes and cellular damage occur with reperfusion. The altered energy substrate availability prior to organ procurement likely plays an important role in graft quality and post-ischemic cardiac recovery. These aspects should, therefore, be considered in clinical protocols, as well as in pre-clinical DCD models. Notably, interventions prior to graft procurement are limited for ethical reasons in DCD donors; thus, it is important to understand these mechanisms to optimize conditions during initial reperfusion in concert with graft evaluation and re-evaluation for the purpose of tailoring and adjusting therapies and ensuring optimal graft quality for transplantation. Full article

A standardized extract of cultured Lentinula edodes mycelia (ECLM, AHCC^®) has been shown to have beneficial effects on organ metabolism. ECLM has been indicated to have liver protective properties by suppressing inflammatory responses. The pathogenesis of hepatic ischemia-reperfusion injury is thought to involve the induction of inflammatory mediators. However, whether ECLM affects inflammatory mediators caused by warm hepatic ischemia-reperfusion injury and partial hepatectomy (HIRI+PH) has not been clarified. In this study, we evaluated the protective effects of ECLM against liver damage caused by HIRI+PH. Rats were fed a normal diet (HIRI+PH) or a normal diet with 2% ECLM (HIRI+PH and ECLM) for ten days, then the liver and duodenal ligament were clamped and subjected to 15 min of hepatic ischemia. After 70% hepatectomy, the inflow occlusion was released, and liver and blood samples were collected at 3, 6, and 24 h. The effect of ECLM on mortality induced by 30 min of ischemia and hepatectomy was evaluated. The results showed that ECLM attenuated pathological liver damage, including apoptosis, in the rats treated with HIRI+PH, and decreased serum aminotransferase activity; ECLM decreased mRNA levels of the inflammation-related genes inducible nitric oxide synthase and C-X-C motif chemokine ligand 1, and increased mRNA levels of interleukin 10, an anti-inflammatory cytokine; ECLM increased hepatocyte growth factor mRNA levels and Ki-67 labeled nuclei in the liver at 24 h; ECLM significantly reduced HIRI+PH-induced mortality. In conclusion, ECLM may prevent HIRI+PH-induced liver injury in part by suppressing various inflammatory responses and promoting liver regeneration. Full article

Sulforaphane (SFN) has various beneficial effects on organ metabolism. However, whether SFN affects inflammatory mediators induced by warm hepatic ischemia/reperfusion injury (HIRI) is unclear. To investigate the hepatoprotective effects of SFN using an in vivo model of HIRI and partial hepatectomy (HIRI + PH), rats were subjected to 15 min of hepatic ischemia with blood inflow occlusion, followed by 70% hepatectomy and release of the inflow occlusion. SFN (5 mg/kg) or saline was randomly injected intraperitoneally 1 and 24 h before ischemia. Alternatively, ischemia was prolonged for 30 min to evaluate the effect on mortality. The influence of SFN on the associated signaling pathways was analyzed using the interleukin 1β (IL-1β)-treated primary cultured rat hepatocytes. In the HIRI + PH-treated rats, SFN reduced serum liver enzyme activities and the frequency of pathological liver injury, such as apoptosis and neutrophil infiltration. SFN suppressed tumor necrosis factor-alpha (TNF-α) mRNA expression and inhibited nuclear factor-kappa B (NF-κB) activation by HIRI + PH. Mortality was significantly reduced by SFN. In IL-1β-treated hepatocytes, SFN suppressed the expression of inflammatory cytokines and NF-κB activation. Taken together, SFN may have hepatoprotective effects in HIRI + PH in part by inhibiting the induction of inflammatory mediators, such as TNF-α, via the suppression of NF-κB in hepatocytes. Full article

Transplanted organs are subjected to harmful conditions through stopping blood flow, hypothermic storage of the graft, and subsequent reperfusion. In particular, kidneys donated from patients after cardiac arrest (DCD) are classified as more vulnerable to ischemia–reperfusion injury (IRI). Hypothermic machine perfusion is proposed as a solution for better kidney storage before transplantation, and it is a good platform for additional graft treatment. Antioxidants have gained interest in regenerative medicine due to their ability to scavenge reactive oxygen species (ROS), which play a key role in IRI. We evaluated the effect of Mitoquinone (MitoQ), a strong mitochondria-targeted antioxidant, administered directly to the perfusing buffer. Rat kidneys were isolated, randomly classified into one of the following groups, donation after brainstem death (DBD), DCD, and DCD with MitoQ, and perfused for 22 hours with a hypothermic machine perfusion system. Subsequently, we detected levels of kidney injury (KIM-1) and oxidative stress (ROS/RNS, cytochrome C oxidase, and mitochondrial integrity) markers. We compared the activation of the apoptosis pathway (caspase 3 and 9), the concentration of phosphorylated Akt (pAkt), and the pAkt/total Akt ratio. MitoQ reduces KIM-1 concentration, total ROS/RNS, and the level of caspases. We observed a decrease in pAkt and the pAkt/total Akt ratio after drug administration. The length of warm ischemia time negatively impacts the graft condition. However, MitoQ added to the perfusing system as an ‘on pump’ therapy mitigates injury to the kidney before transplantation by inhibiting apoptosis and reducing ROS/RNS levels. We propose MitoQ as a potential drug for DCD graft preconditioning. Full article

Cold preservation is a key component to organ procurement and transplantation. Cold preservation functions by slowing metabolic activity of procured organs and begins the period known as cold ischemic time (CIT). Reducing CIT and warm ischemic time (WIT) are paramount to minimizing donor organ damage from ischemia and the build-up of waste products and signals that drive reperfusion injury prior to transplantation into a matching recipient. Preventing damage from CIT and WIT and extending the amount of time that organs can tolerate has been a major goal of organ transplantation since donors and recipients are frequently not located within the same hospital, region, or state. Meanwhile, the amount of CIT that a transplant center is willing to accept differs based on the organ, the institution receiving the organ offer, and the doctor receiving the offer for that institution. With the introduction of a partial heart transplantation conducted last year at Duke University, it is important to discuss how much CIT transplant centers conducting a partial heart transplantation (pHT) are willing to accept. This article will review the physiology of WIT and CIT, associated organ damage, CIT variation among transplant centers and organ types, and provide a brief discussion of the future of pHT-accepted CIT and the need for research in this field. Full article

Warm ischemia-reperfusion injury is a prognostic factor for hepatectomy and liver transplantation. However, its underlying molecular mechanisms are unknown. This study aimed to elucidate these mechanisms and identify the predictive markers of post-reperfusion injury. Rats with normal livers were subjected to 70% hepatic warm ischemia for 15, 30, or 90 min, while those with steatotic livers were subjected to 70% hepatic warm ischemia for only 30 min. The liver and blood were sampled at the end of ischemia and 1, 6, and 24 h after reperfusion. The serum alanine aminotransferase (ALT) activity, Suzuki injury scores, and lipid peroxidation (LPO) products were evaluated. The ALT activity and Suzuki scores increased with ischemic duration and peaked at 1 and 6 h after reperfusion, respectively. Steatotic livers subjected to 30 min ischemia and normal livers subjected to 90 min ischemia showed comparable injury. A similar trend was observed for LPO products. Imaging mass spectrometry of normal livers revealed an increase in lysophosphatidylinositol (LPI (18:0)) and a concomitant decrease in phosphatidylinositol (PI (18:0/20:4)) in Zone 1 (central venous region) with increasing ischemic duration; they returned to their basal values after reperfusion. Similar changes were observed in steatotic livers. Hepatic warm ischemia time-dependent acceleration of PI (18:0/20:4) to LPI (18:0) conversion occurs initially in Zone 1 and is more pronounced in fatty livers. Thus, the LPI (18:0)/PI (18:0/20:4) ratio is a potential predictor of post-reperfusion injury. Full article

Circulatory death donor (DCD) kidneys are increasingly used to enlarge the donor pool. These kidneys undergo ischemia-reperfusion injury, frequently leading to renal fibrosis. Transforming growth factor beta 1 (TGF-β1) and matrix metalloproteases have been identified as central mediators of fibrosis and inhibition of these targets could attenuate fibrosis. We studied whether galunisertib, doxycycline, taurine, and febuxostat alleviated fibrosis in precision-cut kidney slices (PCKS). PCKS were prepared from porcine kidneys that were exposed to 30 min of warm ischemia followed by 3 h of oxygenated hypothermic machine perfusion. We subsequently incubated PCKS for 48 h at 37 °C with the described compounds. To further elucidate the antifibrotic effects of galunisertib, we cultured PCKS with TGF-β1. We first screened the effects of the compounds without TGF-β1. Most significant effects were observed for galunisertib which lowered the expression of ACTA2, TGFB1, FN2, and SERPINE1. We then investigated the effects of galunisertib in fibrotic PCKS incubated with TGF-β1. TGF-β1 significantly increased expression of TGFB1, FN1, SERPINE1, and SERPINH1. Galunisertib, however, attenuated the expression of all fibrosis-related genes. Galunisertib appears to be a promising antifibrotic compound requiring further research in a preclinical model and may ultimately be administered during machine perfusion as an antifibrotic treatment in a transplant setting. Full article

Ischemia-reperfusion injury (IRI), a pathological condition resulting from prolonged cessation and subsequent restoration of blood flow to a tissue, is an inevitable consequence of solid organ transplantation. Current organ preservation strategies, such as static cold storage (SCS), are aimed at reducing IRI. However, prolonged SCS exacerbates IRI. Recent research has examined pre-treatment approaches to more effectively attenuate IRI. Hydrogen sulfide (H₂S), the third established member of a family of gaseous signaling molecules, has been shown to target the pathophysiology of IRI and thus appears to be a viable candidate that can overcome the transplant surgeon’s enemy. This review discusses pre-treatment of renal grafts and other transplantable organs with H₂S to mitigate transplantation-induced IRI in animal models of transplantation. In addition, ethical principles of pre-treatment and potential applications of H₂S pre-treatment in the prevention of other IRI-associated conditions are discussed. Full article

Through kidney transplantation, ischemia/reperfusion is known to induce tissular injury due to cell energy shortage, oxidative stress, and endoplasmic reticulum (ER) stress. ER stress stems from an accumulation of unfolded or misfolded proteins in the lumen of ER, resulting in the unfolded protein response (UPR). Adaptive UPR pathways can either restore protein homeostasis or can turn into a stress pathway leading to apoptosis. We have demonstrated that N1-guanyl-1,7-diamineoheptane (GC7), a specific inhibitor of eukaryotic Initiation Factor 5A (eIF5A) hypusination, confers an ischemic protection of kidney cells by tuning their metabolism and decreasing oxidative stress, but its role on ER stress was unknown. To explore this, we used kidney cells pretreated with GC7 and submitted to either warm or cold anoxia. GC7 pretreatment promoted cell survival in an anoxic environment concomitantly to an increase in xbp1 splicing and BiP level while eiF2α phosphorylation and ATF6 nuclear level decreased. These demonstrated a specific modulation of UPR pathways. Interestingly, the pharmacological inhibition of xbp1 splicing reversed the protective effect of GC7 against anoxia. Our results demonstrated that eIF5A hypusination inhibition modulates distinctive UPR pathways, a crucial mechanism for the protection against anoxia/reoxygenation. Full article

Efforts to decrease the deleterious effects of renal ischemia–reperfusion injury (IRI) are ongoing. Recently, there has been increasing interest in using natural phytochemical compounds as alternative remedies in several diseases. Nerolidol is a natural product extracted from plants with floral odors and has been proven to be effective for the treatment of some conditions. We investigated the effect of nerolidol in a rat model of renal IRI. Nerolidol was dissolved in a vehicle and administered orally as single daily dose of 200 mg/kg for 5 days prior to IRI and continued for 3 days post IRI. G-Sham (n = 10) underwent sham surgery, whereas G-IRI (n = 10) and G-IRI/NR (n = 10) underwent bilateral warm renal ischemia for 30 min and received the vehicle/nerolidol, respectively. Renal functions and histological changes were assessed before starting the medication, just prior to IRI and 3 days after IRI. Nerolidol significantly attenuated the alterations in serum creatinine and urea, creatinine clearance, urinary albumin and the urinary albumin–creatinine ratio. Nerolidol also significantly attenuated the alterations in markers of kidney injury; proinflammatory, profibrotic and apoptotic cytokines; oxidative stress markers; and histological changes. We conclude that nerolidol has a renoprotective effect on IRI-induced renal dysfunction. These findings might have clinical implications. Full article

Microvascular dysfunction (MVD) in cardiac allografts is associated with an impaired endothelial function in the coronary microvasculature. Ischemia/reperfusion injury (IRI) deteriorates endothelial function. Hearts donated after circulatory death (DCD) are exposed to warm ischemia before initiating ex vivo blood perfusion (BP). The impact of cytokine adsorption during BP to prevent MVD in DCD hearts is unknown. In a porcine DCD model, we assessed the microvascular function of hearts after BP with (DCD-BP^CytoS, n = 5) or without (DCD-BP, n = 5) cytokine adsorption (CytoSorb^®). Microvascular autoregulation was assessed by increasing the coronary perfusion pressure, while myocardial microcirculation was measured by Laser-Doppler-Perfusion (LDP). We analyzed the immunoreactivity of arteriolar oxidative stress markers nitrotyrosine and 4-hydroxy-2-nonenal (HNE), endothelial injury indicating cell adhesion molecules CD54, CD106 and CD31, and eNOS. We profiled the concentration of 13 cytokines in the perfusate. The expression of 84 genes was determined and analyzed using machine learning and decision trees. Non-DCD hearts served as a control for the gene expression analysis. Compared to DCD-BP, relative LDP was improved in the DCD-BP^CytoS group (1.51 ± 0.17 vs. 1.08 ± 0.17). Several pro- and anti-inflammatory cytokines were reduced in the DCD-BP^CytoS group. The expression of eNOS significantly increased, and the expression of nitrotyrosine, HNE, CD54, CD106, and CD31, markers of endothelial injury, majorly decreased in the DCD-BP^CytoS group. Three genes allowed exact differentiation between groups; regulation of HIF1A enabled differentiation between perfusion (DCD-BP, DCD-BP^CytoS) and non-perfusion groups. CAV1 allowed differentiation between BP and BP^CytoS. The use of a cytokine adsorption device during BP counteracts preload-dependent MVD and preserves the microvascular endothelium by preventing oxidative stress and IRI of coronary arterioles of DCD hearts. Full article