Danshen protects liver grafts from ischemia/reperfusion injury in experimental liver transplantation in rats

Targeting NF-κB in Hepatic Ischemia-Reperfusion Alleviation: from Signaling Networks to Therapeutic Targeting

Hepatic ischemia-reperfusion injury (HIRI) is a major complication of liver trauma, resection, and transplantation that can lead to liver dysfunction and failure. Scholars have proposed a variety of liver protection methods aimed at reducing ischemia-reperfusion damage, but there is still a lack of effective treatment methods, which urgently needs to find new effective treatment methods for patients. Many studies have reported that signaling pathway plays a key role in HIRI pathological process and liver function recovery mechanism, among which nuclear transfer factor-κB (NF-κB) signaling pathway is one of the signal transduction closely related to disease. NF-κB pathway is closely related to HIRI pathologic process, and inhibition of this pathway can delay oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction. In addition, NF-κB can also interact with PI3K/Akt, MAPK, and Nrf2 signaling pathways to participate in HIRI regulation. Based on the role of NF-κB pathway in HIRI, it may be a potential target pathway for HIRI. This review emphasizes the role of inhibiting the NF-κB signaling pathway in oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction in HIRI, as well as the effects of related drugs or inhibitors targeting NF-κB on HIRI. The objective of this review is to elucidate the role and mechanism of NF-κB pathway in HIRI, emphasize the important role of NF-κB pathway in the prevention and treatment of HIRI, and provide a theoretical basis for the target NF-κB pathway as a therapy for HIRI.

Targeting the Hepatic Microenvironment to Improve Ischemia/Reperfusion Injury: New Insights into the Immune and Metabolic Compartments

Hepatic ischemia/reperfusion injury (IRI) is mainly characterized by high activation of immune inflammatory responses and metabolic responses. Understanding the molecular and metabolic mechanisms underlying development of hepatic IRI is critical for developing effective therapies for hepatic IRI. Recent advances in research have improved our understanding of the pathogenesis of IRI. During IRI, hepatocyte injury and inflammatory responses are mediated by crosstalk between the immune cells and metabolic components. This crosstalk can be targeted to treat or reverse hepatic IRI. Thus, a deep understanding of hepatic microenvironment, especially the immune and metabolic responses, can reveal new therapeutic opportunities for hepatic IRI. In this review, we describe important cells in the liver microenvironment (especially non-parenchymal cells) that regulate immune inflammatory responses. The role of metabolic components in the diagnosis and prevention of hepatic IRI are discussed. Furthermore, recent updated therapeutic strategies based on the hepatic microenvironment, including immune cells and metabolic components, are highlighted.

Research Trends, Hot Spots, and Prospects for Traditional Chinese Medicine in the Field of Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is one of the most common phenomena in ischemic disease or processes that causes progressive disability or even death. It has a major impact on global public health. Traditional Chinese medicine (TCM) has a long history of application in ischemic diseases and has significant clinical effect. Numerous studies have shown that the formulas or single herbs in TCM have specific roles in regulating oxidative stress, anti-inflammatory, inhibiting cell apoptosis, etc., in I/R injury. We used bibliometrics to quantitatively analyze the global output of publications on TCM in the field of I/R injury published in the period 2001–2021 to identify research hotspots and prospects. We included 446 related documents published in the Web of Science during 2001–2021. Visualization analysis revealed that the number of publications related to TCM in the field of I/R injury has increased year by year, reaching a peak in 2020. China is the country with the largest number of publications. Keywords and literature analyses demonstrated that neuroregeneration is likely one of the research hotspots and future directions of research in the field. Taken together, our findings suggest that although the inherent limitations of bibliometrics may affect the accuracy of the literature-based prediction of research hotspots, the results obtained from the included publications can provide a reference for the study of TCM in the field of I/R injury.

Neutralization of CD95 ligand protects the liver against ischemia-reperfusion injury and prevents acute liver failure

Ischemia-reperfusion injury is a common pathological process in liver surgery and transplantation, and has considerable impact on the patient outcome and survival. Death receptors are important mediators of ischemia-reperfusion injury, notably the signaling pathways of the death receptor CD95 (Apo-1/Fas) and its corresponding ligand CD95L. This study investigates, for the first time, whether the inhibition of CD95L protects the liver against ischemia-reperfusion injury. Warm ischemia was induced in the median and left liver lobes of C57BL/6 mice for 45 min. CD95Fc, a specific inhibitor of CD95L, was applied prior to ischemia. Hepatic injury was assessed via consecutive measurements of liver serum enzymes, histopathological assessment of apoptosis and necrosis and caspase assays at 3, 6, 12, 18 and 24 h after reperfusion. Serum levels of liver enzymes, as well as characteristic histopathological changes and caspase assays indicated pronounced features of apoptotic and necrotic liver damage 12 and 24 h after ischemia-reperfusion injury. Animals treated with the CD95L-blocker CD95Fc, exhibited a significant reduction in the level of serum liver enzymes and showed both decreased histopathological signs of parenchymal damage and decreased caspase activation. This study demonstrates that inhibition of CD95L with the CD95L-blocker CD95Fc, is effective in protecting mice from liver failure due to ischemia-reperfusion injury of the liver. CD95Fc could therefore emerge as a new pharmacological therapy for liver resection, transplantation surgery and acute liver failure.

Attenuation of Ischemia-Reperfusion Injury and Improvement of Survival in Recipients of Steatotic Rat Livers Using CD47 Monoclonal Antibody

BACKGROUND

Despite the efficacy of orthotopic liver transplantation in the treatment of end-stage liver diseases, its therapeutic utility is severely limited by the availability of donor organs. The ability to rehabilitate marginal organs, such as steatotic allografts, has the potential to address some of the supply limitations of available organs for transplantation. Steatotic livers are more susceptible to ischemia-reperfusion injury (IRI), which is exacerbated by the thrombospondin-1/CD47 pathway through inhibition of nitric oxide signaling. We postulated that CD47 blockade with a monoclonal antibody specific to CD47, clone 400 (CD47mAb400) may reduce the extent of IRI in steatotic liver allografts.

METHODS

Orthotopic liver transplantation was performed using steatotic liver grafts from Zucker rats transplanted into lean recipients. Control IgG or the CD47mAb400 was administered to the donor livers at procurement. Serum transaminases, histological changes, and animal survival were assessed. Hepatocellular damage, oxidative and nitrosative stress, and inflammation were also quantified.

RESULTS

Administration of CD47mAb400 to donor livers increased recipient survival and resulted in significant reduction of serum transaminases, bilirubin, triphosphate nick-end labeling staining, caspase-3 activity, oxidative and nitrosative stresses, and proinflammatory cytokine expression of TNF-α, IL-6 and IL-1β.

CONCLUSIONS

We conclude that administration of CD47mAb400 to donor grafts may reduce IRI through CD47 blockade to result in improved function of steatotic liver allografts and increased survival of recipients and represent a novel strategy to allow the use of livers with higher levels of steatosis.

Effects and mechanisms of compound Chinese medicine and major ingredients on microcirculatory dysfunction and organ injury induced by ischemia/reperfusion

Microcirculation dysfunction and organ injury after ischemia and reperfusion (I/R) result from a complex pathologic process consisting of multiple links, with metabolism impairment in the ischemia phase and oxidative stress in the reperfusion phase as initiators, and any treatment targeting a single link is insufficient to cope with this. Compound Chinese medicine (CCM) has been applied in clinics in China and some Asian nations for >2000years. Studies over the past decades revealed the protective and therapeutic effect of CCMs and major ingredients on I/R-induced microcirculatory dysfunction and tissue injury in the heart, brain, liver, intestine, and so on. CCM contains diverse bioactive components with potential for energy metabolism regulation; antioxidant effect; inhibiting inflammatory cytokines release; adhesion molecule expression in leukocyte, platelet, and vascular endothelial cells; and the protection of thrombosis, albumin leakage, and mast cell degranulation. This review covers the major works with respect to the effects and underlying mechanisms of CCM and its ingredients on microcirculatory dysfunction and organ injury after I/R, providing novel ideas for dealing with this threat.

Tanshinol suppresses cardiac allograft rejection in a murine model

BACKGROUND

Achieving long-term cardiac allograft survival without continuous immunosuppression is highly desired in organ transplantation. Studies have shown that Salvia miltiorrhiza, an herb also known as danshen, improves microcirculation and is highly effective in treating coronary heart disease. Our objective is to determine whether tanshinol, an ingredient of danshen, improves cardiac allograft survival.

METHODS

Fully vascularized heterotopic heart transplantation was performed using BALB/c mice as donors and C57BL/6 mice as recipients, which were then treated with tanshinol and rapamycin. CD4+FoxP3+ regulatory T cells (Tregs) were quantified by flow analyses, whereas CCL22 was measured by real-time polymerase chain reaction and Western blotting.

RESULTS

We found that tanshinol significantly delayed cardiac allograft rejection. It promoted long-term allograft survival induced by rapamycin, a mammalian target-of-rapamycin (mTOR) inhibitor. Tanshinol increased CD4+FoxP3+ Treg numbers in cardiac allografts, but not spleens and lymph nodes, of recipient mice by enhancing chemokine CCL22 expression in cardiac allografts, especially cardiac dendritic cells. In contrast, rapamycin increased Treg numbers in both lymphoid organs and allografts, suggesting that it generally expands Tregs. Moreover, Tregs induced by rapamycin plus tanshinol were more potent in suppressing T-cell proliferation in vitro than those from untreated recipients. Neutralizing CCL22 hindered CD4+FoxP3+ Treg migration to cardiac allografts and reversed long-term allograft survival induced by tanshinol plus rapamycin.

CONCLUSIONS

Tanshinol suppresses cardiac allograft rejection by recruiting CD4+FoxP3+ Tregs to the graft, whereas rapamycin does so via expanding the Tregs. Thus, tanshinol cooperates with rapamycin to further extend cardiac allograft survival.

Early markers of reperfusion injury after liver transplantation: association with primary dysfunction

BACKGROUND

In patients with end-stage liver disease, liver transplantation is the only available curative treatment. Although the outcome and quality of life in the patients have improved over the past decades, primary dys- or nonfunction (PDF/PNF) can occur. Early detection of PDF and PNF is crucial and could lead to individual therapies. This study was designed to identify early markers of reperfusion injury and PDF in liver biopsies taken during the first hour after reperfusion.

METHODS

Biopsies from donor livers were prospectively taken as a routine during the first hour after reperfusion. Recipient data, transaminases and outcome were routinely monitored. In total, 10 biopsy specimens taken from patients with 90-day mortality and PDF, and patients with long-term survival but without PDF were used for DNA microarrays. Markers that were significantly up- or down-regulated in the microarray were verified using quantitative real-time PCR.

RESULTS

Age, indications and labMELD score were similar in both groups. Peak-transaminases during the first week after transplantation were significantly different in the two groups. In total, 20 differentially regulated markers that correlated to PDF were identified using microarray analysis and verified with quantitative real-time PCR.

CONCLUSIONS

The markers identified in this study could predict PDF at a very early time point and might point to interventions that ameliorate reperfusion injury and thus prevent PDF. Identification of patients and organs at risk might lead to individualized therapies and could ultimately improve outcome.

A systematic review of pharmacological treatment options used to reduce ischemia reperfusion injury in rat liver transplantation

BACKGROUND

Although animal studies models are frequently used for the purpose of attenuating ischemia reperfusion injury (IRI) in liver transplantation (LT), many of pharmacological agents have not become part of clinical routine.

METHODS

A search was performed using the PubMed database to identify agents, from which 58 articles containing 2700 rat LT procedures were selected. The identified pharmacological agents were categorized as follows: I - adenosine agonists, nitric oxide agonists, endothelin antagonists, and prostaglandins, II - Kupffer cell inactivator, III - complement inhibiter, IV - antioxidant, V - neutrophil inactivator, VI -anti-apoptosis agent, VII - heat shock protein and nuclear factor kappa B inducer, VIII - metabolic agent, IX - traditional Chinese medicine, and X - others. Meta-analysis using 7-day-survival rate was also performed with Mantel-Haenszel's Random effects model.

RESULTS

The categorization revealed that the rate of donor-treated experiments in each group was highest for agents from Group II (70%) and VII (71%), whereas it was higher for agents from Group V (83%) in the recipient-treated experiments. Furthermore, 90% of the experiments with agents in Group II provided 7-day-survival benefits. The Risk Ratio (RR) of the meta-analysis was 2.43 [95% CI: 1.88-3.14] with moderate heterogeneity. However, the RR of each of the studies was too model-dependent to be used in the search for the most promising pharmacological agent.

CONCLUSION

With regard to hepatic IRI pathology, the categorization of agents of interest would be a first step in designing suitable multifactorial and pleiotropic approaches to develop pharmacological strategies.

Salvia miltiorrhiza compounds protect the liver from acute injury by regulation of p38 and NFκB signaling in Kupffer cells

CONTEXT

Salvia miltiorrhiza Bunge is a traditional Asian medicine used to treat cerebral and cardiac ischemia. However, the effects of the active compounds of S. miltiorrhiza on liver damage are unclear.

OBJECTIVE

In this study, we tested the effects on acute liver injury of crude S. miltiorrhiza extracts from roots as well as neotanshinone B, dehydromiltirone, tanshinol A, tanshinone I, dihydrotanshinono I, neotanshinone A, cryptanshinono, tanshinone II A, and salvianolie acid B from purified S. miltiorrhiza extracts.

MATERIALS AND METHODS

Various compounds or ethanol extract of S. miltiorrhiza (50, 100, and 200 mg/kg, p.o.) were administered to rats for five consecutive days. After acute carbon tetrachloride (CCl4)-induced liver injury by treatment of rats with a single dose of CCl4 (0.75 mL/kg, p.o), rat liver function was tested by measuring serum biochemical parameters. Serum cytokine concentrations were assessed by enzyme-linked immunosorbent assay (ELISA). Expression of p38 and NFκB was evaluated by western blot.

RESULTS

All S. miltiorrhiza components showed their effects on liver function from the dose from 50 to 200 mg/kg. At the dose of 200 mg/kg, they reduced serum levels of alkaline phosphatase (ALP) by 34-77%, alanine aminotransferase (ALT) by 30-57%, aspartate aminotransferase (AST) by 43-72%, creatine total bilirubin (BIL-T) by 33-81%, albumin (ALB) by 37-67%, indicating that S. miltiorrhiza extracts protected liver from CCl4-induced damage. Moreover, S. miltiorrhiza extracts at 200 mg/kg reduced the increase in the proinflammatory cytokines tumor necrosis factor-α (TNF-α) by 25-82%, interleukin-1 (IL-1) by 42-74% and interleukin-6 (IL-6) by 67-83%, indicating an effect on alleviating liver inflammation. Furthermore, in vitro, S. miltiorrhiza extracts inhibited p38 and NFκB signaling in Kupffer cells. This effect could be a main mechanism by which S. miltiorrhiza protects against acute liver toxicity.

DISCUSSION AND CONCLUSION

Active compounds of S. miltiorrhiza protected the liver from CCl4-induced injury. Protection might have been due to inhibition of p38 and NFκB signaling in Kupffer cells, which subsequently reduced inflammation in the liver.

Machine perfusion in solid organ transplantation: where is the benefit?

BACKGROUND

Machine perfusion (MP) in solid organ transplantation has been a topic of variable importance for decades. At the dawn of organ transplantation, MP was one of the standard techniques for preservation; today's gold standard for organ preservation for transplantation is cold storage (CS). The outcome after transplantation of solid organs has tremendously improved over the last five decades. MP has been continuously under investigation and may be an option for organ preservation in selected cases; however, there is only little evidence from clinical trials that can be used to advocate for MP as a routine organ preservation method.

METHODS

This article reviews the current knowledge on MP in the field of solid organ transplantation with special focus on findings from clinical trials.

CONCLUSION

Especially in heart and lung transplantation, MP seems to be a promising tool to improve postoperative outcome, but a general evidence-based recommendation for or against an application of MP cannot be given due to the lack of the highest level of clinical evidence. Gold standards such as CS should not be left behind without good reason. Randomized clinical trials are desperately needed to further improve outcome and for better understanding of the underlying pathophysiological mechanisms.

Effects of a preconditioning oral nutritional supplement on pig livers after warm ischemia

Background. Several approaches have been proposed to pharmacologically ameliorate hepatic ischemia/reperfusion injury (IRI). This study was designed to evaluate the effects of a preconditioning oral nutritional supplement (pONS) containing glutamine, antioxidants, and green tea extract on hepatic warm IRI in pigs. Methods. pONS (70 g per serving, Fresenius Kabi, Germany) was dissolved in 250 mL tap water and given to pigs 24, 12, and 2 hrs before warm ischemia of the liver. A fourth dose was given 3 hrs after reperfusion. Controls were given the same amount of cellulose with the same volume of water. Two hours after the third dose of pONS, both the portal vein and the hepatic artery were clamped for 40 min. 0.5, 3, 6, and 8 hrs after reperfusion, heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), portal venous flow (PVF), hepatic arterial flow (HAF), bile flow, and transaminases were measured. Liver tissue was taken 8 hrs after reperfusion for histology and immunohistochemistry. Results. HR, MAP, CVP, HAF, and PVF were comparable between the two groups. pONS significantly increased bile flow 8 hrs after reperfusion. ALT and AST were significantly lower after pONS. Histology showed significantly more severe necrosis and neutrophil infiltration in controls. pONS significantly decreased the index of immunohistochemical expression for TNF-α, MPO, and cleaved caspase-3 (P < 0.001). Conclusion. Administration of pONS before and after tissue damage protects the liver from warm IRI via mechanisms including decreasing oxidative stress, lipid peroxidation, apoptosis, and necrosis.

Ischemia/Reperfusion injury in liver surgery and transplantation: pathophysiology

Liver ischemia/reperfusion (IR) injury is caused by a heavily toothed network of interactions of cells of the immune system, cytokine production, and reduced microcirculatory blood flow in the liver. These complex networks are further elaborated by multiple intracellular pathways activated by cytokines, chemokines, and danger-associated molecular patterns. Furthermore, intracellular ionic disturbances and especially mitochondrial disorders play an important role leading to apoptosis and necrosis of hepatocytes in IR injury. Overall, enhanced production of reactive oxygen species, found very early in IR injury, plays an important role in liver tissue damage at several points within these complex networks. Many contributors to IR injury are only incompletely understood so far. This paper tempts to give an overview of the different mechanisms involved in the formation of IR injury. Only by further elucidation of these complex mechanisms IR injury can be understood and possible therapeutic strategies can be improved or be developed.