The effect of ischemic precondition to IL-6 on rat liver ischemia-reperfusion injury in transplantation

The Protective Effect of Nutraceuticals on Hepatic Ischemia-Reperfusion Injury in Wistar Rats

Nutraceuticals are bioactive compounds present in foods, utilized to ameliorate health, prevent diseases, and support the proper functioning of the human body. They have gained attention due to their ability to hit multiple targets and act as antioxidants, anti-inflammatory agents, and modulators of immune response and cell death. Therefore, nutraceuticals are being studied to prevent and treat liver ischemia-reperfusion injury (IRI). This study evaluated the effect of a nutraceutical solution formed by resveratrol, quercetin, omega-3 fatty acid, selenium, ginger, avocado, leucine, and niacin on liver IRI. IRI was performed with 60 min of ischemia and 4 h of reperfusion in male Wistar rats. Afterward, the animals were euthanized to study hepatocellular injury, cytokines, oxidative stress, gene expression of apoptosis-related genes, TNF-α and caspase-3 proteins, and histology. Our results show that the nutraceutical solution was able to decrease apoptosis and histologic injury. The suggested mechanisms of action are a reduction in gene expression and the caspase-3 protein and a reduction in the TNF-α protein in liver tissue. The nutraceutical solution was unable to decrease transaminases and cytokines. These findings suggest that the nutraceuticals used favored the protection of hepatocytes, and their combination represents a promising therapeutic proposal against liver IRI.

Inflammatory response to the ischaemia-reperfusion insult in the liver after major tissue trauma

BACKGROUND

Polytrauma is often accompanied by ischaemia-reperfusion injury to tissues and organs, and the resulting series of immune inflammatory reactions are a major cause of death in patients. The liver is one of the largest organs in the body, a characteristic that makes it the most vulnerable organ after multiple injuries. In addition, the liver is an important digestive organ that secretes a variety of inflammatory mediators involved in local as well as systemic immune inflammatory responses. Therefore, this review considers the main features of post-traumatic liver injury, focusing on the immuno-pathophysiological changes, the interactions between liver organs, and the principles of treatment deduced.

METHODS

We focus on the local as well as systemic immune response involving the liver after multiple injuries, with emphasis on the pathophysiological mechanisms.

RESULTS

An overview of the mechanisms underlying the pathophysiology of local as well as systemic immune responses involving the liver after multiple injuries, the latest research findings, and the current mainstream therapeutic approaches.

CONCLUSION

Cross-reactivity between various organs and cascade amplification effects are among the main causes of systemic immune inflammatory responses after multiple injuries. For the time being, the pathophysiological mechanisms underlying this interaction remain unclear. Future work will continue to focus on identifying potential signalling pathways as well as target genes and intervening at the right time points to prevent more severe immune inflammatory responses and promote better and faster recovery of the patient.

Ischemic Preconditioning Protects Against Hepatic Ischemia-Reperfusion Injury Under Propofol Anesthesia in Rats

BACKGROUND

Propofol is widely used in general anesthesia, and it has been reported to protect various organs against ischemia-reperfusion injury (IRI), including liver. To evaluate the hepatoprotective effects of ischemic preconditioning (IP) under propofol anesthesia, we investigated the possible underlying mechanisms in rats.

METHODS

Male Sprague-Dawley rats were randomly assigned to 3 groups: sham group (n = 5), non-IP group (n = 9; 45 minutes of hepatic ischemia followed by 2 hours of reperfusion), and IP group (n = 9; IP applied as 10 minutes of hepatic ischemia followed by 15 minutes of reperfusion before 45 minutes of ischemia). Anesthesia was maintained with intravenous (IV) infusion of propofol (800 μg/kg/min). Liver enzymes, histopathological changes, and cytokine expression were examined.

RESULTS

The IP group showed significantly lower liver enzyme levels (aspartate aminotransferase, P = .045; alanine aminotransferase, P = .006) and reduced the histologic grades of hepatic injury 2 hours after reperfusion (P = .004) compared to the non-IP group. Lactate dehydrogenase activity (P < .001) and interleukin-6 mRNA levels were significantly higher in the non-IP group than in the sham and IP groups (P = .002, both groups).

CONCLUSIONS

Our results demonstrate that IP under propofol anesthesia significantly attenuated hepatic IRI. The principal mechanism of the protective effects appeared to involve reduced expression of the IL-6 pro-inflammatory cytokine and subsequent reduction of the degree of necrosis.

Intrahepatic biliary strictures after liver transplantation are morphologically similar to primary sclerosing cholangitis but immunologically distinct

OBJECTIVE

Biliary strictures are an important cause of morbidity and mortality in primary hepatic disease and after liver transplantation (LT). We aimed to characterize inflammatory cytokines in biliary fluids in biliary strictures to investigate their immunological origin.

METHODS

We conducted a retrospective study on 72 patients with strictures after LT, eight patients with primary sclerosing cholangitis (PSC) and 15 patients with secondary sclerosing cholangitis (SSC). We measured cytokines interleukin (IL)-2, -4, -6, -10, -17, monocyte chemoattractant protein (MCP)-1, fibroblast growth factor (FGF)-2 and interferon (IFN)-γ as well as biochemical components such as protein and phospholipids in biliary fluid obtained from endoscopic retrograde cholangiography (ERC). Cell viability assays were performed on human cholangiocytes (H69) after being treated with IL-6, IL-4 and IFN-γ.

RESULTS

Bile of patients with diffuse strictures after LT or due to SSC showed low values of all measured cytokines except for IL-6 levels, which were largely elevated in patients with diffuse strictures after LT. Patients high in biliary IL-6 showed an increase in profibrotic markers FGF-2 and MCP-1. In contrast, PSC bile was dominated by a Th1/Th17 profile with elevated IL-2, IL-17 and IFN-γ. In LT patients with biliary strictures, biliary IL-6 negatively predicted retransplantation-free survival after ERC.

CONCLUSION

PSC patients showed a biliary Th1/Th17 cytokine profile, while SSC and diffuse strictures showed low values of cytokines except IL-6. In diffuse intrahepatic strictures after LT, biliary IL-6 is strongly associated with retransplantation-free survival after ERC.

Remifentanil Preconditioning Attenuates Hepatic Ischemia-Reperfusion Injury in Rats via Neuronal Activation in Dorsal Vagal Complex

Remifentanil, an ultra-short acting opiate, has been reported to protect against hepatic ischemia-reperfusion injury, which is a major cause of postoperative liver dysfunction. The objective of this study was to determine whether a central vagal pathway is involved in this protective procedure. Rat models of hepatic ischemia-reperfusion were used in the experimental procedures. The results revealed that intravenous pretreatment with remifentanil decreased serum aminotransferases and hepatic histologic damage; however, an intraperitoneal injection of μ-opioid receptor antagonist did not abolish the protection of remifentanil preconditioning. c-Fos immunofluorescence of the brain stem showed that dorsal motor nucleus of the vagus was activated after remifentanil preconditioning. Moreover, serum alanine aminotransferase, histopathologic damage, and apoptosis decreased in remifentanil preconditioning group compared to vagotomized animals with remifentanil preconditioning, and there was no statistical difference of TNF-α and IL-6 between NS/Va and RPC/Va groups. In addition, remifentanil microinjection into dorsal vagal complex decreased serum aminotransferases, inflammatory cytokines, and hepatic histologic injury and apoptosis, and these effects were also abolished by a peripheral hepatic vagotomy. In conclusion, remifentanil preconditioning conferred liver protection against ischemia-reperfusion injury, which was mediated by the central vagal pathway.

Pre-conditions for eliminating mitochondrial dysfunction and maintaining liver function after hepatic ischaemia reperfusion

The liver, the largest organ with multiple synthesis and secretion functions in mammals, consists of hepatocytes and Kupffer, stem, endothelial, stellate and other parenchymal cells. Because of early and extensive contact with the external environment, hepatic ischaemia reperfusion (IR) may result in mitochondrial dysfunction, autophagy and apoptosis of cells and tissues under various pathological conditions. Because the liver requires a high oxygen supply to maintain normal detoxification and synthesis functions, it is extremely susceptible to ischaemia and subsequent reperfusion with blood. Consequently, hepatic IR leads to acute or chronic liver failure and significantly increases the total rate of morbidity and mortality through multiple regulatory mechanisms. An increasing number of studies indicate that mitochondrial structure and function are impaired after hepatic IR, but that the health of liver tissues or liver grafts can be effectively rescued by attenuation of mitochondrial dysfunction. In this review, we mainly focus on the subsequent therapeutic interventions related to the conservation of mitochondrial function involved in mitigating hepatic IR injury and the potential mechanisms of protection. Because mitochondria are abundant in liver tissue, clarification of the regulatory mechanisms between mitochondrial dysfunction and hepatic IR should shed light on clinical therapies for alleviating hepatic IR‐induced injury.

Hypothermia is better than ischemic preconditioning for preventing early hepatic ischemia/reperfusion in rats

BACKGROUND

Topical hypothermia (TH) and ischemic preconditioning (IPC) are used to decrease I/R injury. The efficacy of isolated or combined use of TH and IPC in the liver regarding inflammation and cytoprotection in early ischemia/reperfusion (I/R) injury needs to be evaluated.

MATERIAL AND METHODS

Wistar rats underwent 70% liver ischemia for 90 min followed by 120 min of reperfusion. Livers of animals allocated in the sham, normothermic ischemia (NI), IPC, TH, and TH+IPC groups were collected for molecular analyses by ELISA and Western blot, aiming to compare proinflammatory, anti-inflammatory, and antioxidant profiles.

RESULTS

Compared with NI, TH presented decreased tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-12 concentrations and increased IL-10 levels. TH animals displayed lower inducible nitric oxide synthase (iNOS) and higher endothelial nitric oxide synthase (eNOS) expressions. NAD(P)H-quinone oxidoreductase-1(NQO1) expression was also lower with TH. Isolated IPC and NI were similar regarding all these markers. TH+IPC was associated with decreased IL-12 concentration and reduced iNOS and NQO1 expressions, similarly to isolated TH. Expression of Kelch-like ECH-associated protein (Keap)-1 was increased and expression of nuclear and cytosolic nuclear erythroid 2-related factor 2 (Nrf2) was decreased with TH+IPC vs. NI.

CONCLUSION

TH was the most effective method of protection against early I/R injury. Isolated IPC entailed triggering of second-line antioxidant defense enzymes. Combined TH+IPC seemed to confer no additional advantage over isolated TH in relation to the inflammatory process, but had the advantage of completely avoid second-line antioxidant defense enzymes.