Hypothermic machine perfusion increases A20 expression which protects renal cells against ischemia/reperfusion injury by suppressing inflammation, apoptosis and necroptosis

The role of neutrophil extracellular trap formation in kidney transplantation: Implications from donors to the recipient

Kidney transplantation remains the gold standard for patients with end-stage renal disease, but severe donor organ shortage has led to long waiting lists. The utilization of expanded criteria donor kidneys within the category of deceased donors has enlarged the pool of available kidneys for transplantation; however, these grafts often have an increased risk for delayed graft function or reduced graft survival following transplantation. During brain or circulatory death, neutrophils are recruited to the vascular beds of kidneys where a proinflammatory microenvironment might prime the formation of neutrophil extracellular traps (NETs), web-like structures, containing proteolytic enzymes, DNA, and histones. NETs are known to cause tissue damage and specifically endothelial damage while activating other systems such as coagulation and complement, contributing to tissue injury and an unfavorable prognosis in various diseases. In lung transplantation and kidney transplantation studies, NETs have also been associated with primary graft dysfunction or rejection. In this review, the role that NETs might play across the different phases of transplantation, already initiated in the donor, during preservation, and in the recipient, will be discussed. Based on current knowledge, NETs might be a promising therapeutic target to improve graft outcomes.

Prompt Thrombo-Inflammatory Response to Ischemia-Reperfusion Injury and Kidney Transplant Outcomes

Introduction

In kidney transplantation (KT), the role of the intravascular innate immune system (IIIS) in response to ischemia-reperfusion injury (IRI) is not well-understood. Here, we studied parallel changes in the generation of key activation products of the proteolytic cascade systems of the IIIS following living donor (LD) and deceased donor (DD) transplantation and evaluated potential associations with clinical outcomes.

Methods

In a cohort study, 63 patients undergoing LD (n = 26) and DD (n = 37) transplantation were prospectively included. Fifteen DD kidneys were preserved with hypothermic machine perfusion (HMP), and the remaining were cold stored. Activation products of the kallikrein-kinin, coagulation, and complement systems were measured in blood samples obtained systemically at baseline and locally from the transplant renal vein at 1, 10, and 30 minutes after reperfusion.

Results

DD kidneys exhibited a prompt and interlinked activation of all 3 cascade systems of IIIS postreperfusion, indicating a robust and local thrombo-inflammatory response to IRI. In this initial response, the complement activation product sC5b-9 exhibited a robust correlation with other IIIS activation markers and displayed a strong association with short-term and mid-term (24-month) graft dysfunction. In contrast, LD kidneys did not exhibit this thrombo-inflammatory response. The use of HMP was associated with reduced thromboinflammation and preserved mid-term kidney function.

Conclusion

Kidneys from DD are vulnerable to a prompt thrombo-inflammatory response to IRI, which adversely affects both short-term and long-term allograft function. Strategies aimed at minimizing graft immunogenicity prior to reperfusion are crucial to mitigate the intricate inflammatory response to IRI.

Necroptosis in Organ Transplantation: Mechanisms and Potential Therapeutic Targets

Organ transplantation remains the only treatment option for patients with end-stage organ dysfunction. However, there are numerous limitations that challenge its clinical application, including the shortage of organ donations, the quality of donated organs, injury during organ preservation and reperfusion, primary and chronic graft dysfunction, acute and chronic rejection, infection, and carcinogenesis in post-transplantation patients. Acute and chronic inflammation and cell death are two major underlying mechanisms for graft injury. Necroptosis is a type of programmed cell death involved in many diseases and has been studied in the setting of all major solid organ transplants, including the kidney, heart, liver, and lung. It is determined by the underlying donor organ conditions (e.g., age, alcohol consumption, fatty liver, hemorrhage shock, donation after circulatory death, etc.), preservation conditions and reperfusion, and allograft rejection. The specific molecular mechanisms of necroptosis have been uncovered in the organ transplantation setting, and potential targeting drugs have been identified. We hope this review article will promote more clinical research to determine the role of necroptosis and other types of programmed cell death in solid organ transplantation to alleviate the clinical burden of ischemia-reperfusion injury and graft rejection.

Liver transcriptomic and methylomic analyses identify transcriptional mitogen-activated protein kinase regulation in facultative hibernation of Syrian hamster

Hibernation consists of alternating torpor-arousal phases, during which animals cope with repetitive hypothermia and ischaemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole-genome bisulfide sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene ontology analysis was performed on 844 differentially expressed genes and confirmed the shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. Additionally, we showed a so far unreported suppression of mitogen-activated protein kinase (MAPK) and protein phosphatase 1 pathways during torpor. Notably, hibernating hamsters showed upregulation of MAPK inhibitors (dual-specificity phosphatases and sproutys) and reduced levels of MAPK-induced transcription factors (TFs). Promoter methylation was found to modulate the expression of genes targeted by these TFs. In conclusion, we document gene regulation between hibernation phases, which may aid the identification of pathways and targets to prevent organ damage in transplantation or ischaemia-reperfusion.

Deficiency of mindin reduces renal injury after ischemia reperfusion

BACKGROUND

Acute renal injury (AKI) secondary to ischemia reperfusion (IR) injury continues to be a significant perioperative problem and there is no effective treatment. Mindin belongs to the mindin/F-spondin family and involves in inflammation, proliferation, and cell apoptosis. Previous studies have explored the biological functions of mindin in liver and brain ischemic injury, but its role in AKI is unknown.

METHOD

To investigate whether mindin has a pathogenic role, mindin knockout (KO) and wild-type (WT) mice were used to establish renal IR model. After 30 min of ischemia and 24 h of reperfusion, renal histology, serum creatinine, and inflammatory response were examined to assess kidney injury. In vitro, proinflammatory factors and inflammatory signaling pathways were measured in mindin overexpression or knockdown and vector cells after hypoxia/reoxygenation (HR).

RESULTS

Following IR, the kidney mindin level was increased in WT mice and deletion of mindin provided significant protection for mice against IR-induced renal injury as manifested by attenuated the elevation of serum creatinine and blood urea nitrogen along with less severity for histological alterations. Mindin deficiency significantly suppressed inflammatory cell infiltration, TNF-α and MCP-1 production following renal IR injury. Mechanistic studies revealed that mindin deficiency inhibits TLR4/JNK/NF-κB signaling activation. In vitro, the expression levels of TNF-α and MCP-1 were increased in mindin overexpression cells compared with vector cells following HR. Moreover, TLR4/JNK/NF-κB signaling activation was elevated in the mindin overexpression cells in response to HR stimulation while mindin knockdown inhibited the activation of TLR4/JNK/ NF-κB signaling after HR in vitro. Further study showed that mindin protein interacted directly with TLR4 protein. And more, mindin protein was confirmed to be expressed massively in renal tubule tissues of human hydronephrosis patients.

CONCLUSION

These data demonstrate that mindin is a critical modulator of renal IR injury through regulating inflammatory responses. TLR4/JNK/NF-κB signaling most likely mediates the biological function of mindin in this model of renal ischemia.

Crystallographic mining of ASK1 regulators to unravel the intricate PPI interfaces for the discovery of small molecule

Protein seldom performs biological activities in isolation. Understanding the protein–protein interactions’ physical rewiring in response to pathological conditions or pathogen infection can help advance our comprehension of disease etiology, progression, and pathogenesis, which allow us to explore the alternate route to control the regulation of key target interactions, timely and effectively. Nonalcoholic steatohepatitis (NASH) is now a global public health problem exacerbated due to the lack of appropriate treatments. The most advanced anti-NASH lead compound (selonsertib) is withdrawn, though it is able to inhibit its target Apoptosis signal-regulating kinase 1 (ASK1) completely, indicating the necessity to explore alternate routes rather than complete inhibition. Understanding the interaction fingerprints of endogenous regulators at the molecular level that underpin disease formation and progression may spur the rationale of designing therapeutic strategies. Based on our analysis and thorough literature survey of the various key regulators and PTMs, the current review emphasizes PPI-based drug discovery’s relevance for NASH conditions. The lack of structural detail (interface sites) of ASK1 and its regulators makes it challenging to characterize the PPI interfaces. This review summarizes key regulators interaction fingerprinting of ASK1, which can be explored further to restore the homeostasis from its hyperactive states for therapeutics intervention against NASH.

The Effect of Hypothermic Machine Perfusion to Ameliorate Ischemia-Reperfusion Injury in Donor Organs

Hypothermic machine perfusion (HMP) has become the new gold standard in clinical donor kidney preservation and a promising novel strategy in higher risk donor livers in several countries. As shown by meta-analysis for the kidney, HMP decreases the risk of delayed graft function (DGF) and improves graft survival. For the liver, HMP immediately prior to transplantation may reduce the chance of early allograft dysfunction (EAD) and reduce ischemic sequelae in the biliary tract. Ischemia-reperfusion injury (IRI), unavoidable during transplantation, can lead to massive cell death and is one of the main causes for DGF, EAD or longer term impact. Molecular mechanisms that are affected in IRI include levels of hypoxia inducible factor (HIF), induction of cell death, endothelial dysfunction and immune responses. In this review we have summarized and discussed mechanisms on how HMP can ameliorate IRI. Better insight into how HMP influences IRI in kidney and liver transplantation may lead to new therapies and improved transplant outcomes.

Advances in Hypothermic and Normothermic Perfusion in Kidney Transplantation

Hypothermic and normothermic machine perfusion in kidney transplantation are purported to exert a beneficial effect on post-transplant outcomes compared to the traditionally used method of static cold storage. Kidney perfusion techniques provide a window for organ reconditioning and quality assessment. However, how best to deliver these preservation methods or improve organ quality has not yet been conclusively defined. This review summarises the promising advances in machine perfusion science in recent years, which have the potential to further improve early graft function and prolong graft survival.

Research Progress of the Application of Hypothermia in the Eye

Hypothermia is widely used in the medical field to protect organs or tissues from damage. Different research fields have different explanations of the protection mechanism of hypothermia. Hypothermia is also widely used in the field of ophthalmology, for example, in the eye bank, the preservation of corneal tissue and the preservation of the eyeball. Low temperature can also be applied to some ophthalmic diseases, such as allergic conjunctivitis, retinal ischemia, and retinal hypoxia. It is used to relieve eye symptoms or reduce tissue damage. Hypothermic techniques have important applications in ophthalmic surgery, such as corneal refractive surgery, vitrectomy surgery, and ciliary body cryotherapy for end-stage glaucoma. Hypothermia can reduce the inflammation of the cornea and protect the retinal tissue. The eyeball is a complex organ, including collagen tissue of the eyeball wall and retinal nerve tissue and retinal blood vessels. The mechanism of low temperature protecting eye tissue is complicated. It is important to understand the mechanism of hypothermia and its applications in ophthalmology. This review introduces the mechanism of hypothermia and its application in the eye banks, eye diseases (allergic conjunctivitis, retinal ischemia, and hypoxia), and eye surgeries (corneal transplant surgery, corneal refractive surgery, and vitrectomy).

Organ preservation solutions: linking pharmacology to survival for the donor organ pathway

PURPOSE OF REVIEW

To provide an understanding of the scientific principles, which underpinned the development of organ preservation solutions, and to bring into context new strategies and challenges for solution development against the background of changing preservation technologies and expanded criteria donor access.

RECENT FINDINGS

Improvements in organ preservation solutions continue to be made with new pharmacological approaches. New solutions have been developed for dynamic perfusion preservation and are now in clinical application. Principles defining organ preservation solution pharmacology are being applied for cold chain logistics in tissue engineering and regenerative medicine.

SUMMARY

Organ preservation solutions support the donor organ pathway. The solution compositions allow additives and pharmacological agents to be delivered direct to the target organ to mitigate preservation injury. Changing preservation strategies provide further challenges and opportunities to improve organ preservation solutions.

Early Protection by Resveratrol in Rat Lung Transplantation

BACKGROUND Resveratrol is a multifunctional bioactive substance that has effects in anti-inflammation and prevention of ischemia-reperfusion injury. This study compared the inflammation and expression of related proteins during the early stages after transplantation to explore the effects and mechanisms of resveratrol on transplanted lung. MATERIAL AND METHODS Sprague-Dawley rats were randomized to receive pretreatment of resveratrol suspension (60 mg/kg; RES group), dexamethasone (1 mg/kg; DEM group), or normal saline solution (2 mL/kg; control group) 1 h before lung transplantation. The cytokine concentration in the serum and bronchoalveolar lavage fluid (BALF) of the recipients was determined 24 h after transplantation. Histopathologic evaluation, including lung injury score, and the expression of necroptosis-associated proteins was assessed. RESULTS Histopathologic evaluation showed pneumocyte damage and endothelialitis associated with hemorrhage in the alveoli in the control group, the severity of which was greater than that in the other 2 groups. The levels of interleukin-6 and tumor necrosis factor-a in the serum and BALF of the RES and DEM groups were lower than those in the control group. The expression of necroptosis-associated proteins in the RES group was lower than that in the control group, and was inversely proportional to lung injury. CONCLUSIONS Pretreatment with resveratrol protected rat lung in the early stages after transplantation. We determined a relationship between necroptosis-associated proteins and transplanted lung injury, which suggests that the mechanism of lung transplantation-associated ischemia-reperfusion injury may be related to necroptosis.

N-n-Butyl Haloperidol Iodide Ameliorates Oxidative Stress in Mitochondria Induced by Hypoxia/Reoxygenation through the Mitochondrial c-Jun N-Terminal Kinase/Sab/Src/Reactive Oxygen Species Pathway in H9c2 Cells

Both c-Jun N-terminal kinase (JNK) and reactive oxygen species (ROS) play important roles in myocardial ischemia/reperfusion (I/R) injury. Our previous studies suggest that N-n-butyl haloperidol iodide (F₂) exerts cardioprotection by reducing ROS production and JNK activation caused by I/R. In this study, we hypothesized that there is a JNK/Sab/Src/ROS pathway in the mitochondria in H9c2 cells following hypoxia/reoxygenation (H/R) that induces oxidative stress in the mitochondria and that F₂ exerts mitochondrial protective effects during H/R injury by modulating this pathway. The results showed that H/R induced higher-level ROS in the cytoplasm on the one hand and JNK activation and translocation to the mitochondria by colocalization with Sab on the other. Moreover, H/R resulted in mitochondrial Src dephosphorylation, and subsequently, oxidative stress evidenced by the increase in ROS generation and oxidized cardiolipin in the mitochondrial membranes and by the decrease in mitochondrial superoxide dismutase activity and membrane potential. Furthermore, treatment with a JNK inhibitor or Sab small interfering RNA inhibited the mitochondrial translocation of p-JNK, decreased colocalization of p-JNK and Sab on the mitochondria, and reduced Src dephosphorylation and mitochondrial oxidative stress during H/R. In addition, Src dephosphorylation by inhibitor PP2 increased mitochondrial ROS production. F₂, like inhibitors of the JNK/Sab/Src/ROS pathway, downregulated the H/R-induced mitochondrial translocation of p-JNK and the colocalization of p-JNK and Sab on the mitochondria, increased Src phosphorylation, and alleviated the above-mentioned mitochondrial oxidative stress. In conclusion, F₂ could ameliorate H/R-associated oxidative stress in mitochondria in H9c2 cells through the mitochondrial JNK/Sab/Src/ROS pathway.

Calcitriol Ameliorates AngiotensinII-Induced Renal Injury Partly via Upregulating A20

Inflammation and reactive oxygen species (ROS) play crucial roles in the progression of chronic kidney diseases. Vitamin D has been shown anti-inflammatory effects, but the underlying mechanism is not fully understood. Here, we investigated whether calcitriol exerts protective effects via upregulating A20 in angiotensinII (AngII)-induced renal injury. Male C57BL/6 mice were infused with vehicle or AngII for 10 days. Calcitriol reduced infiltration of T lymphocytes and macrophages. This reduction of inflammatory cells was accompanied by elevated A20 and decreased pro-inflammatory cytokines (PICs) and reactive oxygen species (ROS). Calcitriol could inhibit NF-κB activation and necroptotic pathway. Induction of A20 was located primarily to the tubular epithelial cells. In rat proximal tubular epithelial cells (NRK-52E), calcitriol stably upregulated A20 and reduced the PICs and ROS. Inhibitory effect of A20 on PICs and ROS depended on suppressing NF-κB pathway and necroptotic pathway, respectively. A20 knockdown diminished the effect of calcitriol on suppressing NF-κB and necroptotic pathways. However, A20 deficiency could not abrogate the inhibitory effect of calcitriol on NF-κB and necroptotic pathways. Our results established that A20 is involved in the renoprotective effect by calcitriol via negatively modulating the NF-κB pathway and necroptotic pathway in AngII-induced renal injury.

Schisantherin A protects renal tubular epithelial cells from hypoxia/reoxygenation injury through the activation of PI3K/Akt signaling pathway

Schisantherin A (SchA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, was reported to possess anti-inflammatory and antioxidant activities. However, its protective effect against renal ischemia-reperfusion (I/R) injury in human renal tubular epithelial cells subjected to hypoxia/reoxygenation (H/R) has never been studied. Thus, herein, we investigated the effect of SchA on renal I/R injury in vitro. Our results demonstrated that SchA pretreatment significantly improved HK-2 cell viability exposed to H/R. Pretreatment with SchA markedly inhibited the levels of reactive oxygen species and malondialdehyde, as well as suppressed the production of tumor necrosis factor-α (TNF-α), interleukin-1β, and interleukin-6 in H/R-stimulated HK-2 cells. In addition, SchA also suppressed H/R-induced HK-2 cell apoptosis. Furthermore, this protective effect of SchA was mediated through the PI3K/Akt signaling pathway in HK-2 cells. These findings showed that SchA may exert a protective effect on renal tubular epithelial cells against H/R injury through the activation of PI3K/Akt signaling pathway.

Ripk3 regulates cardiac microvascular reperfusion injury: The role of IP3R-dependent calcium overload, XO-mediated oxidative stress and F-action/filopodia-based cellular migration

Ripk3-mediated cellular apoptosis is a major contributor to the pathogenesis of myocardial ischemia reperfusion (IR) injury. However, the mechanisms by which Ripk3 influences microvascular homeostasis and endothelial apoptosis are not completely understood. In this study, loss of Ripk3 inhibited endothelial apoptosis, alleviated luminal swelling, maintained microvasculature patency, reduced the expression of adhesion molecules and limited the myocardial inflammatory response. In vitro, Ripk3 deficiency protected endothelial cells from apoptosis and migratory arrest induced by HR injury. Mechanistically, Ripk3 had the ability to migrate onto the endoplasmic reticulum (ER), leading to ER damage, as evidenced by increased IP3R and XO expression. The higher IP3R content was associated with cellular calcium overload, and increased XO expression was involved in cellular oxidative injury. Furthermore, IP3R-mediated calcium overload and XO-dependent oxidative damage were able to initiate cellular apoptosis. More importantly, IP3R and XO also caused F-actin degradation into G-actin via post-transcriptional modification of cofilin, impairing the formation of the filopodia and limiting the migratory response of endothelial cells. Altogether, our data confirmed that Ripk3 was involved in microvascular IR injury via regulation of IP3R-mediated calcium overload, XO-dependent oxidative damage and filopodia-related cellular migration, ultimately leading to endothelial apoptosis and migratory inhibition. These findings provide a potential target for treating cardiac microcirculatory IR injury.

Elevated serum A20 is associated with severity of chronic hepatitis B and A20 inhibits NF-κB-mediated inflammatory response

A20 is a powerful suppressor for inflammatory response. This study aims to determine A20 level in patients with chronic hepatitis B (CHB), and analyze its association with the disease severity. The role of A20 in inflammatory response was further investigated in vivo and in vitro. Our results showed significantly higher A20 in both serum and liver tissues in CHB patients than in health controls. Serum A20 level was positively correlated with ALT, AST and TNF-α. To induce hepatitis with inflammation and liver injury, mice were injected intraperitoneally with D-galactosamine (D-GalN), resulting in rapid increase of A20 in serum and liver tissues. Consistently, HepG2 and Huh-7 cells exposed to Lipopolysaccharide (LPS) or D-GalN were promoted to express A20. Moreover, overexpression or knockdown of A20 inhibited or increased TNF-α secretion separately. A20 significantly reduced pro-inflammatory cytokines expression and down-regulated phospho-IκBα and phospho-p65 in both cells. In conclusion, elevated A20 expression is involved in the severity of CHB, suggesting A20 to be a possible serological biomarker for the disease prognosis. Additionally, the inflammatory response is attenuated by A20 through inhibiting NF-κB activity, which partially contributes to the hepato-protective function of this molecule. Thus, up-regulating A20 might be a potential strategy for preventing the progress of CHB.

Nanoparticle-mediated dual delivery of resveratrol and DAP5 ameliorates kidney ischemia/reperfusion injury by inhibiting cell apoptosis and inflammation

Ischemia reperfusion (I/R) injury is a leading cause of acute kidney injury with high morbidity and mortality due to limited therapy. NMDA receptor inhibitor (DAP5) and resveratrol (Res) could ameliorate kidney I/R injury, but their use is limited by low aqueous solubility and poor stability. Here, we examined the potential protective effects of Res-DAP5 nanoparticles (NP) against renal I/R injury. Mice were subjected to renal ischemia for 30 min followed by reperfusion for 24 h. The results showed that Res-DAP5-NP could decreased serum creatinine (Cr) and urea nitrogen (BUN), alleviated tubular damage and oxidative stress. In addition, Res-DAP5-NP suppressed cell apoptosis, promoted the expression of p-DAPK, and inhibited the expression of p-CaMK and p-AKT. Furthermore, Res-DAP5-NP decreased the production of pro-inflammatory cytokines such as tumor necrosis factor-α, IL-1β, IL-6, and p-IκBα induced by renal I/R injury. In addition, Res-DAP5-NP also attenuated renal I/R injury in vivo, as manifested by increase in cell viability, SOD level, and the expression of p-DAPK, decreases in intracellular Ca²⁺ concentration and the expression of p-CaMK. Taken together, our findings indicates that Res-DAP5-NP could effectively protect renal I/R injury by inhibiting apoptosis and inflammation responses, possibly through AKT/NMDA/CaMK/DAPK and NF-κB pathways.

Curcumin-carrying nanoparticles prevent ischemia-reperfusion injury in human renal cells

Renal ischemia-reperfusion injury (IRI) is a major complication in clinical practice. However, despite its frequency, effective preventive/treatment strategies for this condition are scarce. Curcumin possesses antioxidant properties and is a promising potential protective agent against renal IRI, but its poor water solubility restricts its application. In this study, we constructed curcumin-carrying distearoylphosphatidylethanolamine-polyethylene glycol nanoparticles (Cur-NPs), and their effect on HK-2 cells exposed to IRI was examined in vitro. Curcumin encapsulated in NPs demonstrated improved water solubility and slowed release. Compared with the IRI and Curcumin groups, Cur-NP groups displayed significantly improved cell viability, downregulated protein expression levels of caspase-3 and Bax, upregulated expression of Bcl-2 protein, increased antioxidant superoxide dismutase level, and reduced apoptotic rate, reactive oxygen species level, and malondialdehyde content. Results clearly showed that Cur-NPs demonstrated good water solubility and slow release, as well as exerted protective effects against oxidative stress in cultured HK-2 cells exposed to IRI.

Loss of A20 in BM-MSCs regulates the Th17/Treg balance in Rheumatoid Arthritis

Mesenchymal stem cells (MSCs) are multi-potent cells that are self-renewable and possess the potential to differentiate into multiple lineages. Several studies demonstrated that MSCs could regulate a Th17/Treg balance and could be a potential therapeutic target for Rheumatoid Arthritis (RA). A20 is highly expressed in many cell types after the stimulation of TNF-α, where it may inhibit pro-inflammatory cytokine secretion. However, the expression of A20 in BM-MSCs in RA is not fully understood. In our study, we found that A20 was decreased in RA patients’ bone marrow MSCs (BM-MSCs), and with more IL-6 secretion, the balance of Th17/Treg was broken. In CIA mice, we found a moderate A20 decrease in mice MSCs as compared with those of control group in mRNA and protein levels. However, the IL-6 expression was increased. After umbilical cord MSCs treatment, A20 and IL-6 expressions were equal to the control group. Thus, our study indicates that loss of A20 in MSCs regulates the Th17/Treg balance in RA and the regulatory role of A20 in pro-inflammatory IL-6 production could be a potential target for the transfer of MSCs in RA adoptive therapy.

Renoprotective effect of erythropoietin via modulation of the STAT6/MAPK/NF-κB pathway in ischemia/reperfusion injury after renal transplantation

Ischemia/reperfusion injury (IRI) commonly occurs in renal transplantation. Erythropoietin (EPO) exerts a protective effect in IRI. To investigate the underlying molecular mechanism, rat models of renal IRI were established and treated with EPO and/or lentivirus-mediated EPO-siRNA, the signal transducer and activator of transcription 6 (STAT6) inhibitor AS1517499, the JNK inhibitor SP600125, the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580, and the nuclear factor (NF)-κB inhibitor lactacystin. Histological examination revealed that EPO protected the kidney from IRI, through decreasing the extent of tissue congestion and inflammatory cell infiltration; however, EPO siRNA did not exert the same protective effect. In addition, the EPO level was inversely associated with renal IRI. EPO downregulated the expression of interferon-γ, interleukin (IL)-4, creatinine and caspase-3, and upregulated the expression of IL-10, thymic stromal lymphopoietin, STAT6, p-JNK and p-p38, while the opposite effects were observed with the administration of EPO-siRNA and the specific respective inhibitors. Further results revealed that MAPK (p-JNK and p-p38) acted upstream of NF-κB, and that NF-κB signaling regulated the expression of caspase-1 and -3, which may be responsible for the cytotoxicity associated with IRI. Taken together, the results of the present study demonstrated that EPO exerted a protective effect in renal IRI via the STAT6/MAPK/NF-κB pathway. This protective effect of EPO may improve reperfusion tolerance in ischemic kidneys and benefit transplant recipients.

Hypothermic oxygenated machine perfusion (HOPE) for orthotopic liver transplantation of human liver allografts from extended criteria donors (ECD) in donation after brain death (DBD): a prospective multicentre randomised controlled trial (HOPE ECD-DBD)

INTRODUCTION

Orthotopic liver transplantation (OLT) has emerged as the mainstay of treatment for end-stage liver disease. In an attempt to improve the availability of donor allografts and reduce waiting list mortality, graft acceptance criteria were extended increasingly over the decades. The use of extended criteria donor (ECD) allografts is associated with a higher incidence of primary graft non-function and/or delayed graft function. As such, several strategies have been developed aiming at reconditioning poor quality ECD liver allografts. Hypothermic oxygenated machine perfusion (HOPE) has been successfully tested in preclinical experiments and in few clinical series of donation after cardiac death OLT.

METHODS AND ANALYSIS

HOPE ECD-DBD is an investigator-initiated, open-label, phase-II, prospective multicentre randomised controlled trial on the effects of HOPE on ECD allografts in donation after brain death (DBD) OLT. Human whole organ liver grafts will be submitted to 1-2 hours of HOPE (n=23) via the portal vein before implantation and are going to be compared with a control group (n=23) of patients transplanted after conventional cold storage. Primary (peak and Δ peak alanine aminotransferase within 7 days) and secondary (aspartate aminotransferase, bilirubin and international normalised ratio, postoperative complications, early allograft dysfunction, duration of hospital and intensive care unit stay, 1-year patient and graft survival) endpoints will be analysed within a 12-month follow-up. Extent of ischaemia-reperfusion (I/R) injury will be assessed using liver tissue, perfusate, bile and serum samples taken during the perioperative phase of OLT.

ETHICS AND DISSEMINATION

The study was approved by the institutional review board of the RWTH Aachen University, Aachen, Germany (EK 049/17). The current paper represent the pre-results phase. First results are expected in 2018.

TRIAL REGISTRATION NUMBER

NCT03124641.

Gene expression in the twilight of death: The increase of thousands of transcripts has implications to transplantation, cancer, and forensic research

After a vertebrate dies, many of its organ systems, tissues, and cells remain functional while its body no longer works as a whole. We define this state as the "twilight of death" - the transition from a living body to a decomposed corpse. We claim that the study of the twilight of death is important to ethical, legal and medical science. We examined gene expression at the twilight of death in the zebrafish and mouse reaching the conclusion that apparently thousands of transcripts significantly increase in abundance from life to several hours/days postmortem relative to live controls. Transcript dynamics of different genes provided "proof-of-principle" that models accurately predict an individual's elapsed-time-of-death (i.e. postmortem interval). While many transcripts were associated with survival and stress compensation, others were associated with epigenetic factors, developmental control, and cancer. Future studies are needed to determine whether the high incidence of cancer in transplant recipients is due to the postmortem processes in donor organs.

Tisp40 deficiency attenuates renal ischemia reperfusion injury induced apoptosis of tubular epithelial cells

Renal ischemia reperfusion (IR) is a major cause of acute kidney injury (AKI) and no effective treatments have been established. Tisp40 is a transcription factor of the CREB/ATF family and involves in cell apoptosis, proliferation and differentiation, but its role in renal IR remains unknown. Here, we investigated the role of Tisp40 in renal IR injury. In vivo, Tisp40 knockout (KO) and wild-type (WT) mice were subjected to thirty minutes of bilateral renal ischemia and 48h reperfusion, the blood and kidneys were harvested for analysis. In vitro, Tisp40 overexpression and vector cells were subjected to hypoxia/reoxygenation (HR), the apoptosis rate and the expressions of related proteins were measured. Following IR, the expressions of Tisp40 protein, serum creatinine (sCr), blood urea nitrogen (BUN) and apoptosis of tubular cells were significantly increased in WT mice. However, Tisp40 deficiency significantly attenuated the increase of sCr, BUN and apoptosis of tubular cells. Following HR, apoptosis of tubular cells was increased in Tisp40 overexpression cells compared with vector cells. Mechanistically, Tisp40 promoted the expressions of C/EBP homologous protein (CHOP), Bax and Cleaved caspase3 and suppressed the expression of Bcl-2 in renal IR injury. In conclusion, Tisp40 aggravates tubular cells apoptosis in renal IR injury.

The regulatory and signaling mechanisms of the ASK family

Apoptosis signal-regulating kinase 1 (ASK1) was identified as a MAP3K that activates the JNK and p38 pathways, and subsequent studies have reported ASK2 and ASK3 as members of the ASK family. The ASK family is activated by various intrinsic and extrinsic stresses, including oxidative stress, ER stress and osmotic stress. Numerous lines of evidence have revealed that members of the ASK family are critical for signal transduction systems to control a wide range of stress responses such as cell death, differentiation and cytokine induction. In this review, we focus on the precise signaling mechanisms of the ASK family in response to diverse stressors.