Identification of the Anti-ischemia-reperfusion Injury Effect of Baicalein from Scutellaria Baicalensis Georgi in Liver Transplantation.

BACKGROUND: The complex etiology of Ischemia-Reperfusion Injury (IRI) induced by liver transplantation (LT) and the "one-target-focused" method limit the development of effective therapeutic interventions. We aimed to reveal the specific active ingredients and mechanisms involved in the Chinese herb Scutellaria baicalensis Georgi (SBG) in alleviating IRI in LT. METHODS: The active ingredients and potential macromolecular targets of SBG were screened through related databases. The differentially expressed genes of LT were obtained from GSE151648. The protein-protein interaction network was constructed by the STRING database, and Cytoscape 3.7.1 was used to construct a compound-target-disease network. GO and KEGG enrichment analyses were performed on the DAVID database. Finally, the main active components of SBG and the corresponding mechanisms were verified in a donation after circulatory death (DCD) rat LT model. RESULTS: Thirty-two active ingredients of SBG and their targets were identified, and a total of 38 intersection targets were obtained. GO function and KEGG pathway enrichment analyses demonstrated that the plasma membrane and its components play an important role. Molecular docking showed baicalein, the core component of SBG, had a strong binding ability to all hub targets. Next, in DCD rats, baicalein was proven to improve liver function, alleviate pathological injury and apoptosis, and increase the survival rate. Baicalein also significantly affected the expression of 7 hub genes. Furthermore, baicalein could inhibit ferroptosis by inhibiting phospholipid peroxidation. CONCLUSION: Baicalein, the main component of SBG, could alleviate IRI, affect the expression of hub genes, and inhibit ferroptosis in LT.

Wogonin Alleviates DCD Liver Ischemia/Reperfusion Injury by Regulating ALOX15/iNOS-mediated Ferroptosis.

BACKGROUND: Donation after circulatory death livers are more susceptible to ischemia/reperfusion injury (IRI) because of a longer period of warm ischemia. Growing evidence now suggests that ferroptosis plays a key regulatory role in the development of IRI, so targeting ferroptosis may be an effective strategy to alleviate IRI in liver transplantation (LT). METHODS: Using donation after circulatory death LT models in rats and oxygen-glucose deprivation/reoxygenation (OGD/R) models in BRL-3A cells, we tested the effect of the Chinese medicine monomer wogonin on liver IRI and explored the specific mechanism. RESULTS: Wogonin attenuated liver IRI and increased the survival rate of rats by inhibiting lipid peroxidation and ferroptosis. Mechanistically, arachidonic acid 15-lipoxygenase-1 (ALOX15) and inducible nitric oxide synthase (iNOS) were identified as potential targets of baicalein through bioinformatics analysis combined with in vivo and in vitro experiments. This result was further confirmed by molecular docking and cellular thermal shift assays. Finally, we silenced ALOX15 and iNOS in the OGD/R cell model and found that silencing ALOX15 and iNOS could reproduce the regulatory effect of wogonin and abrogate the regulatory effect of wogonin. CONCLUSIONS: In brief, this study emphasizes that wogonin exerts a protective effect in liver IRI through the regulation of ALOX15- and iNOS-mediated ferroptosis. ALOX15 and iNOS are potential targets for intervention in IRI induced by LT, and wogonin is a drug candidate for LT patients.

The positive efficacy of dexmedetomidine on the clinical outcomes of patients undergoing renal transplantation: evidence from meta-analysis.

INTRODUCTION: Whether dexmedetomidine (DEX), an anesthetic adjuvant, can improve renal transplant outcomes is not clear. METHODS: We systematically identified clinical trials in which DEX was administered in renal transplantation (RT). On November 1, 2022, we searched The Cochrane Library, MEDLINE, EMBASE and https://www. CLINICALTRIALS: gov/. The main outcomes were delayed graft function and acute rejection. RESULTS: A total of seven studies were included in the meta-analysis. The results showed that compared with the control, DEX significantly reduced the occurrence of delayed graft function (RR 0.76; 95% CI 0.60-0.98), short-term serum creatinine [postoperative day (POD) 2: (MD -22.82; 95% CI -42.01 - -3.64)] and blood urea nitrogen [POD 2: (MD -2.90; 95% CI -5.10 - -0.70); POD 3: (MD 2.07; 95% CI -4.12 - -0.02)] levels, postoperative morphine consumption (MD -4.27; 95% CI -5.92 - -2.61) and the length of hospital stay (MD -0.85; 95% CI-1.47 - -0.23). However, DEX did not reduce the risk of postoperative acute rejection (RR 0.75; 95% CI 0.45-1.23). The results of the subgroup analysis showed that country type, donor type, and average age had a certain impact on the role of DEX. CONCLUSIONS: DEX may improve the short-term clinical outcome of RT and shorten the length of hospital stay of patients.

Effect of dexmedetomidine on liver transplantation: a meta-analysis.

Background: Dexmedetomidine (DEX), an adjuvant anesthetic, may improve the clinical outcomes of liver transplantation (LT). Methods: We summarized the relevant clinical trials of DEX in patients undergoing LT. As of 30 January 2023, we searched The Cochrane Library, MEDLINE, EMBASE, Clinical Trial.gov and the WHO ICTRP. The main outcomes were postoperative liver and renal function. The random effect model or fixed effect model was used to summarize the outcomes across centers based on the differences in heterogeneity. Results: The meta-analysis included nine studies in total. Compared with the control group, the DEX group had a reduced warm ischemia time (MD-4.39; 95% CI-6.74--2.05), improved postoperative liver (peak aspartate transferase: MD-75.77, 95% CI-112.81--38.73; peak alanine transferase: MD-133.51, 95% CI-235.57--31.45) and renal function (peak creatinine: MD-8.35, 95% CI-14.89--1.80), and a reduced risk of moderate-to-extreme liver ischemia-reperfusion injury (OR 0.28, 95% CI 0.14-0.60). Finally, the hospital stay of these patients was decreased (MD-2.28, 95% CI-4.00--0.56). Subgroup analysis of prospective studies showed that DEX may have better efficacy in living donors and adult recipients. Conclusion: DEX can improve short-term clinical outcomes and shorten the hospital stay of patients. However, the long-term efficacy of DEX and its interfering factors deserves further study. Systematic Review: identifier CRD42022351664.

N-acetylcysteine in the Donor, Recipient, or Both Donor and Recipient in Liver Transplantation: A Systematic Review With Meta-analysis and Trial Sequential Analysis.

BACKGROUND: N-acetylcysteine (NAC) is a potentially effective drug for treating ischemia-reperfusion injury in transplanted livers, but its effect remains controversial. METHODS: A systematic review and meta-analysis of relevant clinical trials published and registered in the Cochrane Library, MEDLINE, EMBASE, ClinicalTrial.gov , WHO ICTRP, etc, before March 20, 2022 were conducted and registered with PROSPERO (CRD42022315996). Data were pooled using a random effects model or a fixed effects model based on the amount of heterogeneity. RESULTS: Thirteen studies with 1121 participants, 550 of whom received NAC, were included. Compared with the control, NAC significantly reduced the incidence of primary graft nonfunction (relative risk [RR], 0.27; 95% confidence interval [CI], 0.08-0.96), the incidence of postoperative complications (RR, 0.52; 95% CI, 0.41-0.67), the peak postoperative aspartate transferase level (mean difference [MD], -267.52; 95% CI, -345.35 to -189.68), and the peak alanine transferase level (MD, -293.29; 95% CI, -370.39 to -216.20). NAC also improved 2-y (RR, 1.18; 95% CI, 1.01-1.38) graft survival rate. However, NAC increased the intraoperative cryoprecipitate (MD, 0.94; 95% CI, 0.42-1.46) and red blood cell (MD, 0.67; 95% CI, 0.15-1.19) requirements. Moreover, NAC was administered in various modes in these studies, including to the donor, recipient, or both. Subgroup analysis and network meta-analysis showed that NAC administration to recipients could play a more significant role than the other 2 administration modes. CONCLUSIONS: Our study supports the protective effect of NAC against LT-induced ischemia-reperfusion injury and shows better clinical outcomes of NAC administration to recipients.

Dimethyloxalylglycine pretreatment of living donor alleviates both donor and graft liver ischemia-reperfusion injury in rats.

Background: Under the circumstance of the increasing waiting list for liver transplantation, living donor liver transplantation (LDLT) can alleviate the shortage of liver donors to some extent. However, how to reduce both donor and graft ischemia-reperfusion injury (IRI) is still an unsolved problem in LDLT. Hypoxia-induced transcription factor 1 (HIF1) activation is considered an important mechanism of cellular adaptation to hypoxia, and early activation of HIF1 may be a new way to alleviate liver IRI. Therefore, we aimed to investigate the impact of the HIF1 stabilizer dimethyloxalylglycine (DMOG) on IRI and the survival rate of donors and recipients of rat LDLT. Methods: Seventy percent partial liver resection and 30% partial liver transplantation were used to simulate donor and recipient of clinical LDLT. Rats were treated with DMOG (40 mg/kg) or with an equivalent amount of saline. The expression of HIF1 and downstream targets was analyzed after 2 h of reperfusion. Liver function and histopathology, apoptosis and oxidative stress levels were detected 6 h after reperfusion. At the same time, the 7-day survival rate of rats was calculated. Results: DMOG pretreatment significantly reduced IR-induced injury in the donor and recipient, which was manifested by reducing liver function damage and promoting tissue recovery. Meanwhile, compared with the untreated group, the oxidative stress level and the cell apoptosis rate were decreased in the group pretreated with DMOG. In addition, the transcription and expression of HIF1 target genes in the DMOG group were significantly enhanced. Remarkably, DMOG also increased the survival rate of the recipient. Conclusion: This study provides the first evidence that DMOG pretreatment of donors significantly alleviates liver IRI in both donors and recipients and increases the survival rate of recipients in LDLT. Therefore, DMOG may be a promising strategy for improving LDLT in the future.

Ischemic postconditioning improves the outcome of organs from donors after cardiac death in a pig liver transplantation model and provides synergistic protection with hypothermic machine perfusion.

AIM: This study investigated whether ischemic postconditioning (IPO) improved the outcome of organs from donors after cardiac death and had a synergistic effect with hypothermic machine perfusion (HMP) in a pig liver transplantation model. METHODS: A donor after cardiac death (DCD) model was developed in 48 healthy Bama miniature pigs randomly divided into four groups: simple cold storage group (SCS group), IPO group, HMP group, HMP-IPO group. The levels of serum alanine aminotransferase (ALT), total bilirubin, histopathological findings, apoptotic activity of hepatocytes, international normalized ratio (INR), tumor necrosis factor-α (TNF-α), and Malondialdehyde (MDA) were compared. RESULTS: All recipients in the SCS group died within 6 h after transplantation. The livers of the recipients in the IPO had 50% survival on day 5. HMP allowed 83.3% survival and HMP-IPO allowed 100% survival. After reperfusion, the recipients in the IPO and HMP-IPO group had lower ALT and total bilirubin levels, less Suzuki score, less apoptosis, and less injury to hepatocytes and biliary ducts and attenuated inflammatory response and oxidative load. CONCLUSIONS: IPO improved the outcome of organs from donors after cardiac death and had a synergistic effect with HMP in the pig liver transplantation model.

Toll-Like Receptor 3 Activator Preconditioning Enhances Modulatory Function of Adipose­Derived Mesenchymal Stem Cells in a Fully MHC-Mismatched Murine Model of Heterotopic Heart Transplantation.

BACKGROUND Donor-specific tolerance is the ultimate goal in organ transplantation. Diverse approaches, including the use of mesenchymal stem cells (MSCs), have been investigated to induce graft tolerance. Non-stimulated MSCs showed limited regulatory functions through interaction with multiple immune-regulatory cells, such as regulatory T cells (Tregs). To augment their functions, MSCs have been preconditioned with toll-like receptor (TLR3/4) agonist in autoimmune disease models, but results were conflicting. MATERIAL AND METHODS We evaluated the immunomodulatory effects of mouse adipose-derived mesenchymal stem cells (ADSCs) preconditioned with various combinations of TLR3/4 agonist and antagonists, including polyinosinic-polycytidylic acid poly(I:C)-TLR3 agonist, lipopolysaccharide (LPS) -TLR4 agonist, and TAK242-TLR4 antagonist. In vitro and in vivo experiments including mixed lymphocyte reaction, cytokines measurement, Tregs analysis, and a fully mismatched MHC heterotopic heart transplantation in mice (BALB/c to C57BL/6) were conducted. RESULTS ADSCs preconditioned with poly(I:C) showed the highest efficiency in inhibiting lymphocyte proliferation, which was correlated with the upregulation of fibrinogen-like protein 2 (FGL2), an effector molecule of Tregs. The mean survival of cardiac allografts was extended from 8 to 12 days by intravenous injection of a single dose of ADSCs preconditioned with TLR3 agonist. The proportion of Tregs in the recipient's spleen was significantly increased by injecting the poly(I:C)-stimulated ADSCs. CONCLUSIONS These results show that short-term TLR3 agonist preconditioning enhances the immunomodulatory efficacy of ADSCs, which can induce the generation of Tregs and upregulate the expression of FGL2, thereby improving the outcome of patients receiving organ transplantation.

Effect of the Selective NLRP3 Inflammasome Inhibitor mcc950 on Transplantation Outcome in a Pig Liver Transplantation Model With Organs From Donors After Circulatory Death Preserved by Hypothermic Machine Perfusion.

BACKGROUND: We investigated whether the outcome of organs from donors after circulatory death (DCD) can be improved by the addition of mcc950 to the perfusate of the hypothermic machine perfusion (HMP) system and intravenous mcc950 injection after transplantation in a pig liver transplantation model. METHODS: Thirty-six healthy Bama mini pigs randomized into 3 groups. All the DCD livers were preserved in an HMP system after 2 hours of simple cold storage. In HMP-Postop group, mcc950 was added to the perfusate; in the control group and Postop group, the perfusate was normal LPS. After transplantation, the pigs in the Postop group and HMP-Postop group were intravenously administered 3 mg/kg mcc950, at the time of reperfusion and on day 2 and day 3 after transplantation. During the 3-day follow-up period, general operative characteristics, and serological markers and histological features related to ischemia reperfusion injury were examined. RESULTS: The HMP-Postop group suffer the lightest ischemia reperfusion injury (IRI), and functioned best after transplantation. Model for the Early Allograft Function Score (predictor of long-term survival), degree of injury in the hepatocytes and rate of apoptosis was lowest in the HMP-Postop group. Further, in the HMP-Postop group, the nucleotide-binding domain leucine-rich repeat containing family pyrin domain containing 3 inflammasome pathway activation was lowest, and the level of IL-1ß was lowest. Postop group functioned better than control group, but not comparable with HMP-Postop group. CONCLUSIONS: The outcome of DCD organs can be improved by the addition of mcc950 to the perfusate of the HMP system and intravenous injection of mcc950 after transplantation.