Ischemic preconditioning attenuates ischemia/reperfusion injury in rat steatotic liver: role of heme oxygenase-1-mediated autophagy

Development and validation of a model for early survival prediction following liver transplantation based on donor and recipient characteristics

BACKGROUND

Circulating cytokine levels not only correlate with the progression of liver disease but also serve as indicators for the infection status of the body. Growing evidence points to the connection between donor cytokines and graft function following transplantation. This study set out to explore the clinical significance of donor cytokines in predicting liver transplantation prognosis.

METHODS

Data from 172 deceased donor liver transplantations conducted between 2017 and 2022, with available donor serum cytokine information, were collected. The subjects were randomly divided into estimation (n = 120) and validation (n = 52) groups to establish and validate the model. The newly developed SA10 score was compared against established models EAD, MEAF, L-GrAFT7, and L-GrAFT10.

RESULTS

Donor IL-10, along with donor age and recipient AST peak value within the first 7 days post-operation, was identified as an independent factor associated with recipient survival and was incorporated into the SA10 score. SA10 exhibited robust predictive capability, particularly for 1-month survival (AUC = 0.90, 95% CI = 0.84-0.96), outperforming EAD (AUC = 0.75, 95% CI = 0.60-0.90, p = 0.04) and L-GrAFT7 (AUC = 0.65, 95% CI = 0.49-0.81, p < 0.01). Comparable performance was observed between SA10, MEAF, and L-GrAFT10.

CONCLUSION

Donor IL-10 independently influences recipient survival, with the SA10 score demonstrating comparable and even superior predictive ability compared to existing models.

Autophagy in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (HIRI) is a major complication of liver resection or liver transplantation that can seriously affect patient's prognosis. There is currently no definitive and effective treatment strategy for HIRI. Autophagy is an intracellular self-digestion pathway initiated to remove damaged organelles and proteins, which maintains cell survival, differentiation, and homeostasis. Recent studies have shown that autophagy is involved in the regulation of HIRI. Numerous drugs and treatments can change the outcome of HIRI by controlling the pathways of autophagy. This review mainly discusses the occurrence and development of autophagy, the selection of experimental models for HIRI, and the specific regulatory pathways of autophagy in HIRI. Autophagy has considerable potential in the treatment of HIRI.

Novel Targets and Therapeutic Strategies to Protect Against Hepatic Ischemia Reperfusion Injury

Hepatic ischemia reperfusion injury (IRI), a fascinating topic that has drawn a lot of interest in the last few years, is a major complication caused by a variety of clinical situations, such as liver transplantation, severe trauma, vascular surgery, and hemorrhagic shock. The IRI process involves a series of complex events, including mitochondrial deenergization, metabolic acidosis, adenosine-5'-triphosphate depletion, Kupffer cell activation, calcium overload, oxidative stress, and the upregulation of pro-inflammatory cytokine signal transduction. A number of protective strategies have been reported to ameliorate IRI, including pharmacological therapy, ischemic pre-conditioning, ischemic post-conditioning, and machine reperfusion. However, most of these strategies are only at the stage of animal model research at present, and the potential mechanisms and exact therapeutic targets have yet to be clarified. IRI remains a main cause of postoperative liver dysfunction, often leading to postoperative morbidity or even mortality. Very recently, it was reported that the activation of peroxisome proliferator-activated receptor γ (PPARγ), a member of a superfamily of nuclear transcription factors activated by agonists, can attenuate IRI in the liver, and FAM3A has been confirmed to mediate the protective effect of PPARγ in hepatic IRI. In addition, non-coding RNAs, like LncRNAs and miRNAs, have also been reported to play a pivotal role in the liver IRI process. In this review, we presented an overview of the latest advances of treatment strategies and proposed potential mechanisms behind liver IRI. We also highlighted the role of several important molecules (PPARγ, FAM3A, and non-coding RNAs) in protecting against hepatic IRI. Only after achieving a comprehensive understanding of potential mechanisms and targets behind IRI can we effectively ameliorate IRI in the liver and achieve better therapeutic effects.

New Insights Into the Role of Autophagy in Liver Surgery in the Setting of Metabolic Syndrome and Related Diseases

Visceral obesity is an important component of metabolic syndrome, a cluster of diseases that also includes diabetes and insulin resistance. A combination of these metabolic disorders damages liver function, which manifests as non-alcoholic fatty liver disease (NAFLD). NAFLD is a common cause of abnormal liver function, and numerous studies have established the enormously deleterious role of hepatic steatosis in ischemia-reperfusion (I/R) injury that inevitably occurs in both liver resection and transplantation. Thus, steatotic livers exhibit a higher frequency of post-surgical complications after hepatectomy, and using liver grafts from donors with NAFLD is associated with an increased risk of post-surgical morbidity and mortality in the recipient. Diabetes, another MetS-related metabolic disorder, also worsens hepatic I/R injury, and similar to NAFLD, diabetes is associated with a poor prognosis after liver surgery. Due to the large increase in the prevalence of MetS, NAFLD, and diabetes, their association is frequent in the population and therefore, in patients requiring liver resection and in potential liver graft donors. This scenario requires advancement in therapies to improve postoperative results in patients suffering from metabolic diseases and undergoing liver surgery; and in this sense, the bases for designing therapeutic strategies are in-depth knowledge about the molecular signaling pathways underlying the effects of MetS-related diseases and I/R injury on liver tissue. A common denominator in all these diseases is autophagy. In fact, in the context of obesity, autophagy is profoundly diminished in hepatocytes and alters mitochondrial functions in the liver. In insulin resistance conditions, there is a suppression of autophagy in the liver, which is associated with the accumulation of lipids, being this is a risk factor for NAFLD. Also, oxidative stress occurring in hepatic I/R injury promotes autophagy. The present review aims to shed some light on the role of autophagy in livers undergoing surgery and also suffering from metabolic diseases, which may lead to the discovery of effective therapeutic targets that could be translated from laboratory to clinical practice, to improve postoperative results of liver surgeries when performed in the presence of one or more metabolic diseases.

Heme Oxgenase-1, a Cardinal Modulator of Regulated Cell Death and Inflammation

Heme oxygenase catalyzes the rate-limiting step in heme degradation in order to generate biliverdin, carbon monoxide (CO), and iron. The inducible form of the enzyme, heme oxygenase-1 (HO-1), exerts a central role in cellular protection. The substrate, heme, is a potent pro-oxidant that can accelerate inflammatory injury and promote cell death. HO-1 has been implicated as a key mediator of inflammatory cell and tissue injury, as validated in preclinical models of acute lung injury and sepsis. A large body of work has also implicated HO-1 as a cytoprotective molecule against various forms of cell death, including necrosis, apoptosis and newly recognized regulated cell death (RCD) programs such as necroptosis, pyroptosis, and ferroptosis. While the antiapoptotic potential of HO-1 and its reaction product CO in apoptosis regulation has been extensively characterized, relatively fewer studies have explored the regulatory role of HO-1 in other forms of necrotic and inflammatory RCD (i.e., pyroptosis, necroptosis and ferroptosis). HO-1 may provide anti-inflammatory protection in necroptosis or pyroptosis. In contrast, in ferroptosis, HO-1 may play a pro-death role via enhancing iron release. HO-1 has also been implicated in co-regulation of autophagy, a cellular homeostatic program for catabolic recycling of proteins and organelles. While autophagy is primarily associated with cell survival, its occurrence can coincide with RCD programs. This review will summarize the roles of HO-1 and its reaction products in co-regulating RCD and autophagy programs, with its implication for both protective and detrimental tissue responses, with emphasis on how these impact HO-1 as a candidate therapeutic target in disease.

Salidroside inhibits apoptosis and autophagy of cardiomyocyte by regulation of circular RNA hsa_circ_0000064 in cardiac ischemia-reperfusion injury

Salidroside (Sal), a natural extract of Rhodiola rosea, shows a latent effect on protecting cardiovascular system. Our study explored the effect of salidroside on ischemia-reperfusion (I/R) injury in rat heart. I/R was performed on Wistar rat hearts, and Sal pretreatment was performed in I/R rats. Cardiac marker enzyme, myocardial infarct size, malondialdehyde (MDA) and superoxide dismutase (SOD) content were then measured. Compared with the untreated group, Sal pretreatment observably ameliorated the cardiac function, decreased the myocardial infarct size, reduced the levels of cardiac lactate creatine kinase-MB (CK-MB) and dehydrogenase (LDH), and inhibited the anti-oxidative stress. In addition, Sal treatment also significantly inhibited autophagy and apoptosis, which could be partially reversed by Rapamycin (RAPA), an autophagic agonist. Furthermore, Sal treatment attenuated autophagy by up-regulating the expression of hsa_circ_0000064 (circ-0000064) and Rapamycin (RAPA) treatment abolished it. Our study showed that Sal protected the heart from I/R injury, which might berelated to the upregulation of circ-0000064 and the inhibition of autophagy.

Therapeutic strategies for ischemia reperfusion injury in emergency medicine

Ischemia reperfusion (IR) injury occurs when blood supply, perfusion, and concomitant reoxygenation is restored to an organ or area following an initial poor blood supply after a critical time period. Ischemia reperfusion injury contributes to mortality and morbidity in many pathological conditions in emergency medicine clinical practice, including trauma, ischemic stroke, myocardial infarction, and post‐cardiac arrest syndrome. The process of IR is multifactorial, and its pathogenesis involves several mechanisms. Reactive oxygen species are considered key molecules in reperfusion injury due to their potent oxidizing and reducing effects that directly damage cellular membranes by lipid peroxidation. In general, IR injury to an individual organ causes various pro‐inflammatory mediators to be released, which could then induce inflammation in remote organs, thereby possibly advancing the dysfunction of multiple organs. In this review, we summarize IR injury in emergency medicine. Potential therapies include pharmacological treatment, ischemic preconditioning, and the use of medical gases or vitamin therapy, which could significantly help experts develop strategies to inhibit IR injury.

Heme oxygenase-1/carbon monoxide as modulators of autophagy and inflammation

Heme oxygenase-1 (HO-1) catalyzes heme degradation to generate biliverdin-IXα, carbon monoxide (CO), and iron. The HO-1/CO system confers cytoprotection in animal models of organ injury and disease, via modulation of inflammation and apoptosis. Recent studies have uncovered novel anti-inflammatory targets of HO-1/CO including regulation of the autophagy and inflammasome pathways. Autophagy is a lysosome-dependent program for the turnover of cellular organelles such as mitochondria, proteins, and pathogens; which may downregulate inflammatory processes. Therapeutic modulation of autophagy by CO has been demonstrated in models of sepsis. The nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome regulates the maturation of pro-inflammatory cytokines. CO can regulate NLRP3 inflammasome activation and associated pro-inflammatory cytokines production and promote the resolution of inflammation by upregulating the synthesis of specialized pro-resolving mediators (SPMs). Mitochondria may represent a proximal target of HO-1/CO action. HO-1 may localize to mitochondria in response to stress, while CO can moderate mitochondrial dysfunction and regulate mitochondrial autophagy (mitophagy) and biogenesis. The interplay between mitochondrial autophagy, mitochondrial dysfunction, and the regulation and resolution of inflammation may make important contributions to the protection afforded by HO-1/CO in cellular and organ injury models. Recent studies have continued to explore the potential of CO for clinical applications.

Nrf2-miR-129-3p-mTOR Axis Controls an miRNA Regulatory Network Involved in HDACi-Induced Autophagy

Histone deacetylase inhibitors (HDACis) are the recommended treatment for many solid tumors; however, resistance is a major clinical obstacle for their efficacy. High levels of the transcription factor nuclear factor erythroid 2 like-2 (Nrf2) in cancer cells suggest a vital role in chemoresistance, and regulation of autophagy is one mechanism by which Nrf2 mediates chemoresistance. Although the molecular mechanisms underlying this activity are unclear, understanding them may ultimately improve therapeutic outcomes following HDACi treatment. In this study, we found that HDACi treatment increased Nrf2 mRNA and protein levels and enhanced Nrf2 transcriptional activity. Conversely, Nrf2 knockdown or inhibition blocked HDACi-induced autophagy. In addition, a microRNA (miRNA) array identified upregulation of miR-129-3p in response to Nrf2 overexpression. Chromatin immunoprecipitation assays confirmed miR-129-3p to be a direct Nrf2 target. RepTar and RNAhybrid databases indicated mammalian target of rapamycin (mTOR) as a potential miR-129-3p target, which we experimentally confirmed. Finally, Nrf2 inhibition or miR-129-3p in combination with HDACis increased cell death in vitro and in vivo. Collectively, these results demonstrated that Nrf2 regulates mTOR during HDACi-induced autophagy through miRNA-129-3p and inhibition of this pathway could enhance HDACi-mediated cell death.

Killing Two Angry Birds with One Stone: Autophagy Activation by Inhibiting Calpains in Neurodegenerative Diseases and Beyond

Proteolytic machineries execute vital cellular functions and their disturbances are implicated in diverse medical conditions, including neurodegenerative diseases. Interestingly, calpains, a class of Ca²⁺-dependent regulatory proteases, can modulate the degradational system of autophagy by cleaving proteins involved in this pathway. Moreover, both machineries are common players in many molecular pathomechanisms and have been targeted individually or together, as a therapeutic strategy in experimental setups. In this review, we briefly introduce calpains and autophagy, with their roles in health and disease, and focus on their direct pathologically relevant interplay in neurodegeneration and beyond. The modulation of calpain activity may comprise a promising treatment approach to attenuate the deregulation of these two essential mechanisms.

Diverse Functions of Autophagy in Liver Physiology and Liver Diseases

Autophagy is a catabolic process by which eukaryotic cells eliminate cytosolic materials through vacuole-mediated sequestration and subsequent delivery to lysosomes for degradation, thus maintaining cellular homeostasis and the integrity of organelles. Autophagy has emerged as playing a critical role in the regulation of liver physiology and the balancing of liver metabolism. Conversely, numerous recent studies have indicated that autophagy may disease-dependently participate in the pathogenesis of liver diseases, such as liver hepatitis, steatosis, fibrosis, cirrhosis, and hepatocellular carcinoma. This review summarizes the current knowledge on the functions of autophagy in hepatic metabolism and the contribution of autophagy to the pathophysiology of liver-related diseases. Moreover, the impacts of autophagy modulation on the amelioration of the development and progression of liver diseases are also discussed.

Young plasma attenuates age-dependent liver ischemia reperfusion injury

Aging is often associated with a decreased autophagic activity that contributes to the high sensitivity of aged livers to ischemia reperfusion injury (IRI). Blood from young animals can positively affect aged animals. This study was designed to evaluate the effect of young plasma in a model of liver IRI in aged rats. Aged rats were treated with pooled plasma collected from young rats before ischemia. Administration of young plasma restored aging-induced suppression in hepatic autophagic activity and reduced liver IRI. Inhibition of the young-plasma-restored autophagic activity abrogated the beneficial effect of young plasma against liver IRI. Similarly, young serum restored autophagic activity and reduced cellular injury after hypoxia/reoxygenation (H/R) in primary old rat hepatocytes. Mechanistic studies showed thatadministration of young plasma increased AMPK phosphorylation and led to unc-51-like autophagy activating kinase (ULK)1 activation. Furthermore, AMPK-inhibition abrogated the young serum-induced ULK1 activation and autophagic activity and diminished the protective action of young serum against H/R injury in primary old rat hepatocytes, whereas AMPK-activation potentiated the effects of young serum. Young plasma could restore age-impaired autophagy, at least in part, via AMPK/ULK1 signaling. Restoration of age-impaired autophagic activity may be a critical contributing mechanism to young-plasma-afforded protection against liver IRI in aged rats.-Liu, A., Yang, J., Hu, Q., Dirsch, O., Dahmen, U., Zhang, C., Gewirtz, D. A., Fang, H., Sun, J. Young plasma attenuates age-dependent liver ischemia reperfusion injury.

Autophagy and Akt in the protective effect of erythropoietin helix B surface peptide against hepatic ischaemia/reperfusion injury in mice

Helix B surface peptide (HBSP) is an erythropoietin (EPO)-derived peptide that protects tissue from the risks of elevated blood pressure and thrombosis. This study focused on the protection of HBSP in hepatic ischaemia/reperfusion (I/R) by enhancing the level of autophagy. In detail, we randomly divided C57BL/6 mice into sham-operated, hepatic ischaemia/reperfusion (I/R), I/R + HBSP, I/R + HBSP + 3-methyladenine (autophagy inhibitor), I/R + HBSP + rapamycin (mTOR inhibitor), and I/R + HBSP + Ly294002 (Akt inhibitor) groups. We assessed alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in mouse sera, and performed haematoxylin/eosin (HE) staining, immunohistochemistry, electron microscopy, immunofluorescence microscopy, and western blotting on liver tissue to detect the degree of liver injury, liver apoptosis, autophagy, and the expression of microtubule associated protein 1 light chain 3 alpha (Map1lc3, or LC3), Beclin 1, phospho-mTOR, mTOR, phospho-Akt (P-Akt), and Akt. HBSP relieved hepatic I/R injury in a concentration-independent manner. The expression of LC3II, LC3I, and Beclin 1, and the formation of autophagosomes, in the I/R + HBSP group were higher than those in the I/R group. The protective effects of HBSP were abolished by 3-methyladenine and, to a lesser extent, Ly294002, but enhanced by rapamycin. Furthermore, In vivo, HBSP also protected against hypoxia injury induced by cobalt chloride (CoCl₂) through improving the level of autophagy. Therefore, HBSP protected against hepatic I/R injury, mainly via regulating autophagy by targeting mTOR.

Rapamycin induces the expression of heme oxygenase-1 and peroxyredoxin-1 in normal hepatocytes but not in tumorigenic liver cells

Rapamycin (sirolimus) is employed as an immunosuppressant following liver transplant, to inhibit the re-growth of cancer cells following liver resection for hepatocellular carcinoma (HCC), and for the treatment of advanced HCC. Rapamycin also induces the expression of antioxidant enzymes in the liver, suggesting that pretreatment with the drug could provide a potential strategy to reduce ischemia reperfusion injury following liver surgery. The aim of this study was to further investigate the actions of rapamycin in inducing expression of the antioxidant enzymes heme oxygenase-1 (HO-1) and peroxiredoxin-1 (Prx-1) in normal liver and in tumorigenic liver cells. A rat model of segmental hepatic ischemia and reperfusion, cultured freshly-isolated rat hepatocytes, and tumorigenic H4IIE rat liver cells in culture were employed. Expression of HO-1 and Prx-1 was measured using quantitative PCR and western blot. Rapamycin pre-treatment of normal liver in vivo or normal hepatocytes in vitro led to a substantial induction of mRNA encoding HO-1 and Prx-1. The dose-response curve for the action of rapamycin on mRNA expression was biphasic, showing an increase in expression at 0 - 0.1 μM rapamycin but a decrease from maximum at concentrations greater than 0.1 μM. By contrast, in H4IIE cells, rapamycin inhibited the expression of HO-1 and Prx-1 mRNA. Oltipraz, an established activator of transcription factor Nrf2, caused a large induction of HO-1 and Prx-1 mRNA. The dose response curve for the inhibition by rapamycin of HO-1 and Prx-4 mRNA expression, determined in the presence of oltipraz, was monophasic with half maximal inhibition at about 0.01 μM. It is concluded that, at concentrations comparable to those used clinically, pre-treatment of the liver with rapamycin induces the expression of HO-1 and Prx-1. However, the actions of rapamycin on the expression of these two antioxidant enzymes in normal hepatocytes are complex and, in tumorigenic liver cells, differ from those in normal hepatocytes. Further studies are warranted to evaluate preconditioning the livers of patients subject to liver resection or liver transplant with rapamycin as a viable strategy to reduce IR injury following liver surgery.

MMP9 is involved in HO-1-mediated upregulation of apical junctional complex in Caco-2 cells under oxygen-glucose deprivation

Ischemia reperfusion injury is a critical factor in the recovery process after intestine trauma and the functional restoration of intestinal reconstruction. This study was the first to explore the expression of apical junctional complex (AJC) induced by heme oxygenase-1 (HO-1) in Caco-2 cells in oxygen-glucose deprivation (OGD) models. Here we showed that HO-1 was upregulated after OGD. Notably, activation of HO-1 largely enhanced the expression of AJC proteins including Claudin-4, E-cadherin and β-catenin in Caco-2 cells, but decreased the expression of matrix metalloproteinase 9 (MMP9). Knockdown of HO-1 attenuated the OGD-induced overexpression of AJC proteins but promoted the expression of MMP9. Interestingly, inhibition of MMP9 further enhanced AJC expression. These results suggest that HO-1 is involved in OGD-evoked upregulation of AJC proteins, which is partly mediated by MMP9 pathway. High expression of HO-1 may play an important role in the pathophysiological process of ischemia reperfusion injury and has potential clinical value for the treatment of intestine related diseases.

Young plasma reverses age-dependent alterations in hepatic function through the restoration of autophagy

Recent studies showing the therapeutic effect of young blood on aging‐associated deterioration of organs point to young blood as the solution for clinical problems related to old age. Given that defective autophagy has been implicated in aging and aging‐associated organ injuries, this study was designed to determine the effect of young blood on aging‐induced alterations in hepatic function and underlying mechanisms, with a focus on autophagy. Aged rats (22 months) were treated with pooled plasma (1 ml, intravenously) collected from young (3 months) or aged rats three times per week for 4 weeks, and 3‐methyladenine or wortmannin was used to inhibit young blood‐induced autophagy. Aging was associated with elevated levels of alanine transaminase and aspartate aminotransferase, lipofuscin accumulation, steatosis, fibrosis, and defective liver regeneration after partial hepatectomy, which were significantly attenuated by young plasma injections. Young plasma could also restore aging‐impaired autophagy activity. Inhibition of the young plasma‐restored autophagic activity abrogated the beneficial effect of young plasma against hepatic injury with aging. In vitro, young serum could protect old hepatocytes from senescence, and the antisenescence effect of young serum was abrogated by 3‐methyladenine, wortmannin, or small interfering RNA to autophagy‐related protein 7. Collectively, our data indicate that young plasma could ameliorate age‐dependent alterations in hepatic function partially via the restoration of autophagy.

Isoflurane Preconditioning Alleviated Murine Liver Ischemia and Reperfusion Injury by Restoring AMPK/mTOR-Mediated Autophagy

BACKGROUND

Isoflurane has a pharmacological preconditioning effect against ischemia injury in the heart, kidney, and brain, but whether and how isoflurane preconditioning protects livers against ischemia and reperfusion (IR) injury is unclear.

METHODS

Mice were randomly divided into an isoflurane preconditioning (ISO) group and control group, receiving 1.5% isoflurane or carrier gas for 40 minutes, respectively (n = 8/group). A partial warm liver IR model was used, and liver injury was evaluated. Primary hepatocytes were pretreated with 1.5% isoflurane for 2 hours before the induction of cell death by hydrogen peroxide. Cell death and survival were evaluated with the lactate dehydrogenase and cell counting kit-8 assay. Autophagy and regulatory molecules in stressed livers and hepatocytes were analyzed by Western blot (n = 6/group). An autophagy inhibitor (3-methyladenine [3-MA]) and 5' adenosine monophosphate-activated protein kinase (AMPK) inhibitor (dorsomorphin) were administered in vivo (n = 8/group) and in vitro (n = 6/group).

RESULTS

Compared to that observed in the control group, mice in the ISO group showed reduced liver injury (alanine aminotransferase [ALT] levels, control versus ISO group, 8285 ± 769 vs 4896 ± 917 U/L, P < .001) and enhanced hepatocellular antiapoptosis in livers after IR. Furthermore, liver autophagy was restored by ISO as indicated by elevated LC3B II protein levels accompanied with increased p62 degradation. The in vitro study of primary hepatocytes also found that ISO effectively attenuated hepatocyte cell death induced by hydrogen peroxide. In addition, 3-MA pretreatment showed no significant influence in the control group, but abrogated the protective role of ISO both in stressed livers (ALT levels, phosphate-buffered saline + ISO versus 3-MA + ISO group, 5081 ± 294 vs 8663 ± 607 U/L, P < .001) and in hepatocytes. Finally, signaling pathway analysis demonstrated that AMPK was activated by ISO. Pretreatment with an AMPK inhibitor also abrogated liver protection by ISO (ALT levels, phosphate-buffered saline + ISO versus dorsomorphin [DOR] + ISO group, 5081 ± 294 vs 8710 ± 500 U/L, P < .001), with no significant effect in control mice.

CONCLUSIONS

Our results indicate that isoflurane preconditioning attenuates liver IR injury via AMPK/mTOR-mediated hepatocellular autophagy restoration. Our findings provide a novel potential therapeutic strategy for managing liver IR injury.

TIM-1 attenuates the protection of ischemic preconditioning for ischemia reperfusion injury in liver transplantation

Ischemic preconditioning (IPC) has been introduced to protect grafts against ischemic reperfusion injury (IRI) during liver transplantation (LT) in recent years. However, the underlying molecular mechanisms of IPC are not fully understood. We aimed to confirm whether the efficacy of IPC is dependent on T cell Immunoglobulin and Mucin domain-containing molecules-1 (TIM-1). Quantitative real-time reverse transcription PCR and western blotting were used to detect the expression of genes of interest. Graft function was assessed using the levels of alanine transaminase (ALT) and aspartate transaminase (AST), percentage of apoptosis cells and pathological examination. IPC treatment alleviated graft function after ischemic reperfusion. AST, ALT, CD68, CD3 positive cells and tissue myeloperoxidase activity were decreased significantly by IPC. IPC decreased the expressions of the cytokines and chemokines. Compared with the IRI group, TIM-1 expression and TIM-1 positive cells were inhibited significantly in the IPC group. TIM-1 blockage abolished the protective effect of IPC on IRI damage. IPC could not further improve graft function and decrease the sequestration of immune cells after blocking TIM-1 signaling. IPC is a convenient therapeutic strategy against IRI during LT. The benefit of IPC depends on TIM-1 signaling.