Lack of a Protective Effect of Insulin on Three Reperfusion-Liver Injury Models in Rats and Mice

An Analysis of the Risk Factors for New-Onset Diabetes Mellitus After Liver Transplantation

Objective

To investigate the risk factors related to new-onset diabetes mellitus (NODM) and the significance of IL-6.

Methods

A retrospective analysis was conducted on clinical data from 64 patients who received either a living donor liver transplantation or a donation after circulatory death from September 2013 to October 2020 and attended regular follow-up visits for six or more months. During follow-up, patients were randomized into groups and followed up until the completion of the study or the death of the patient.

Results

The incidence of NODM was 31.25% (n = 20). The median age in the NODM group was 52.15 years (p < 0.01). Age (OR = 1.089; 95% CI: 0.0211-0.1495, p = 0.003) and elevated preoperative IL-6 (OR = 1.122; 95% CI: 0.0619-0.1677, p = 0.029) were found to be independent risk factors for NODM. HBV-induced liver cirrhosis, warm ischemia time (WIT), body mass index (BMI), and high preoperative fasting blood glucose (FBG) were also found to be risk factors for NODM. The recipient had a higher risk of NODM if the donor had a high BMI and poor hepatic function. The concentrations of IL-6, procalcitonin (PCT), FBG, and tacrolimus (TAC) in the first month postoperatively were significantly higher in the NODM group than in the NO-NODM group. The survival rate of the patients was not affected by NODM.

Conclusion

HBV-induced liver cirrhosis, WIT, BMI, and high preoperative FBG levels are risk factors for NODM, and age and preoperative IL-6 levels are independent risk factors. To a certain extent, higher BMI and poor hepatic function had reference significance for the incidence of NODM. Patients with a high concentration of FBG, IL-6, and TAC in the first month postoperatively had an increased risk of suffering from NODM.

Effect of propofol on the skeletal muscle insulin receptor in rats with hepatic ischemia-reperfusion injury

Objective

To investigate the effect of propofol on the expression and phosphorylation of the skeletal muscle insulin receptor and its substrates following hepatic ischemia-reperfusion injury (HIRI).

Methods

Sixty healthy Wistar rats were divided randomly into a propofol group (P) and an ischemia-reperfusion group (I/R). Rats in the P group received propofol infusion prior to ischemia and during a 120-minute post-reperfusion period. Plasma glucose and insulin concentrations were measured, as well as expression levels of the insulin signaling proteins insulin receptor (IR) β unit (IRβ) and IR substrate 1 (IRS-1). In addition, tyrosine phosphorylation levels of these proteins were measured in skeletal muscle.

Results

Plasma glucose levels in the two groups were higher at 2 hours after reperfusion (T2) versus exposure of the hepatic hilum (T1). Plasma glucose levels in the I/R group were higher than those in the P group, while insulin levels at T2 were lower. In addition, phosphotyrosine levels of IRβ and IRS-1 were decreased by 32.1% and 22.4%, respectively.

Conclusion

Propofol increased phosphotyrosine levels of IRβ and IRS-2, resulting in an alleviation of increased plasma glucose levels following HIRI.

Hepatic ischemia-reperfusion induces insulin resistance via down-regulation during the early steps in insulin signaling in rats

BACKGROUND

The effects of hepatic ischemia-reperfusion (I/R) on insulin signaling remain unclear. We observed changes in insulin secretion and signal protein expression during the early steps in insulin signaling after hepatic I/R in rats.

MATERIALS AND METHODS

Eighty healthy Wistar rats were randomly divided into an I/R group and a control (C) group. After we exposed the hepatic hilum, ischemia was induced by clamping the hepatic artery and portal vein for 30 minutes and then the liver was reperfused for 2 hours in the I/R group; a show procedure was done in the C group. Blood samples were obtained after exposure of the hepatic hilum (T1) and 2 hours after reperfusion in the I/R group (T2) and 2.5 hours after T1 in the C group (T2). We measured glucose and insulin plasma concentrations. We determined the expressions of insulin signaling proteins, including insulin receptor (IR) beta unit (IR beta), IR substrate 1 (IRS-1), IRS-2, and P85 in phosphatidylinositol 3-kinase (PI3K) and tyrosine phosphorylation of these proteins in liver and skeletal muscle.

RESULTS

Plasma glucose concentrations increased in both groups at T2 (P < .01) and were higher in the I/R group (P < .01). Insulin concentrations in the I/R group did not change significantly at T2. Insulin concentrations at T2 were higher than those at T1 in the C group (P < .05). Expressions of insulin signal proteins showed no significant difference between the 2 groups; however, tyrosine phosphorylation of IR beta, IRS-1, IRS-2, and the interactions between IRS-1 in skeletal muscle or IRS-2 in liver and PI3K were significantly lower in the I/R group than the C group.

CONCLUSION

Hepatic I/R inhibited insulin secretion and induced insulin resistance via down-regulation during the early steps in insulin signaling in rats.