The Effects Of GLUT4 And PPP1Cgamma Expression On The Perioperative Insulin Resistance In The Liver Transplantation Patients

PartⅠThe effects of skeletal GLUT4 and PPPlCgamma expression on the insulin resistance in the liver cirrhosis patientsIntroduction:About 60-80%of patients with liver cirrhosis have glucose intolerance and 10-20%can develop diabetes mellitus(GM) eventually.Central hyperinsulinemia and peripheral insulin-resistance are the main explanations for the high prevalence of diabetes in patients with liver cirrhosis.Insulin resistance refers to the lower sensitivity of the insulin target tissue to insulin.Insulin must combine with the insulin receptor on the target cell membrane which can activate a series of signal transduction system,and ultimately make glucose transporter4(GLUT4) translocate to the cell sursace and then GLUT4 transport glucose outside the cell into the target cell.After transported into cells by GLUT4,glucose is mainly transformed to glucogen.Recently,insulin was shown to stimulate a cascade of phosphorylation-dependent kinases which ultimately activate a glycogen-bound subunit of a phosphatase(regulatory subunit of phosphatase-1,PP1) which promotes dephosphorylation GS by the catalytic subunit to synthesize glycogen. Glucose transport,mediated by GLUT4 translocation,is a rate limiting step in glucose metabolism.Lower expression or insufficient translocation of GLUT4 may be one of the reasons of insulin resistance.It is reported that defective expression or the polymorphism of PPP1R3 which encodes the regulatory subunit of PP1 might be related to the insulin resistance because of lower activity of glycogen synthetase.Reports have said that the insulin resistance in the patients with liver cirrhosis manifest mainly a defective insulin-mediated glucose uptake in peripheral tissue,where nonoxidative glucose disposal(glucogen synthesis mainly) seems to be chiefly impaired,however there are few reports about the effects of GLUT4 and PPPlCgamma(the catalytic subunit of PP1) on the insulin resistance in liver cirrhosis patients.To investigate the effects of GLUT4 and PPP1Cgamma expression on the perioperative insulin resistance in the lever transplantation patients,we should at first study the the effects of GLUT4 and PPP1Cgamma expression on the insulin resistance in liver cirrhosis patients and explore the mechanism of insulin resistance in liver cirrhosis patients who are the main candidates of liver transplantation in our country.So,we would detect and compare the FSB,fast serum insulin,C-peptide,insulin index and skeletal expression of GLUT4,PPP1 gamma between the healthy people and patients with compensated and uncompensated liver cirrhosis.Material and methods:25 living-related donors(control group),17 patients with compensated liver cirrhosis who were selected to have splenectomy because of portal hypertention with chronic hepatitis B(group2,Child-Pugh classification A) and 20 patients with uncompensated liver cirrhosis who had the operation of liver transplantation(group3: Child-Pugh classification C 12cases,B 8 cases ) were recruited in our hospital.We detected FSB,serum insulin,C peptide concentration before anesthesia and the skeletal expression of GLUT4 and PPP1Cgamma of the three groups at the beginning of the operations by western-blot and Real-time PCR,meanwhile,we also studied their differences among the groups by statistical ways with SPSS software.Results:The level of FSB of the two groups with liver cirrhosis is significantly higher than that of the control group(p<0.01);There is no difference between the two cirrhosis groups(P>0.05).Fasting serum insulin,C peptide concentration with liver cirrhosis is significantly higher than that of control group(P<0.01),moreover,the level of fasting serum insulin,C peptide with uncompensated liver cirrhosis is significantly higher than that of the compensated liver cirrhosis group(p<0.05).The insulin sensitive index of the liver cirrhosis groups is significantly lower than that of the control group.Although The insulin sensitive index of the uncompensated liver cirrhosis group is lower than that of the compensated liver cirrhosis group,the difference is not significant.The expression of GLUT4 exists no difference among the three groups.The expression of PPP1Cgamma in liver cirrhosis groups is significantly lower than that of the control group(p<0.01),however,There was no difference between the two liver cirrhosis groups.Conclusion:The patients with liver cirrhosis exist insulin resistance;The skeletal expression of GLUT4 is normal in liver cirrhosis patients,however,the expression of PPPlCgamma in skeletal muscle is significantly lower.Insulin resistance in liver cirrhosis patients probably is related to the negative effect of the lower expression of PPPlCgamma on glycogen synthesis.Insulin resistance in liver cirrhosis patients probably is not related to the amount of GULT4 expression. PartⅡThe effects of liver transplantation on the insulin resistance and skeletal expression of GLUT4,PPP1Cgamma of the patientsIntroduction:Liver transplantation is the only definitive way of therapy for patients with end-stage liver diseases,however,its operative trauma,stress and the pathophisilogical specialty of the operation can affect homeostasis of the patients.One of the changes of homeostasis is that the patients manifest hyperglycemia and sever insulin resistance during liver transplantation.Perioperative hyperglycemia and insulin resistance can result in electrolyte imbalance,even hyperosmolar coma.They are also the risk factors of post-operative recognition dysfunction and postoperative infection.Perioperative hyperglycemia and insulin resistance of liver transplantation can develop post-transplantation Diabetes eventually which increased the graft and patient morbidity and mortality.Insulin resistance refers to the lower sensitivity of the insulin target tissue to insulin.Insulin must combine with the insulin receptor on the target cell membrane which can activate a series of signal transduction system,and ultimately make glucose transporter4(GLUT4) translocate to the cell sursace and then GLUT4 transport glucose outside the cell into the target cell.After transported into cells by GLUT4,glucose is mainly transformed to glucogen to maintain glucose homeostasis.Recently,insulin was shown to stimulate a cascade of phosphorylation-dependent kinases which ultimately activate a glycogen-bound subunit of a phosphatase(regulatory subunit of phosphatase-1,PP1) which promotes dephosphorylation GS by the catalytic subunit to synthesize glycogen.Glucose transport,mediated by GLUT4 translocation,is a rate limiting step in glucose metabolism.Lower expression or insufficient translocation of GLUT4 may be one of the reasons of insulin resistance.It is reported that defective expression or the polymorphism of PPP1R3 which encodes the regulatory subunit of PP1 might be related to the insulin resistance because of lower activity of glycogen synthetase.There are few reports about the effects of GLUT4 and PPP1Cgamma(the catalytic subunit of PP1) on the insulin resistance in liver transplantation patients.At present,the research on insulin resistance is mainly focused on the patients with type 2 Diabetes.Although there are some Controversial reports about the perioperative hyperglycemia and insulin resistance in the liver transplantation patients,they were at the level of glucose metabolism related hormones.Our previous study demonstrated that the liver transplantation patients exist cirrhosis related insulin resistance and lower skeletal expression of PPP1Cgamma before transplantation which may be some of the reasons that cause the perioperative insulin resistance in the liver transplantation patients.We would like to study the effects of liver transplantation operation on the patient's insulin sensitivity and expression of skeletal GLUT4 and PPP1Cgamma by comparing the FSB,serum insulin,C peptide concentration and expression of skeletal GLUT4 and PPP1Cgamma before and after liver transplantation.Material and methods:20 patients with uncompensated liver cirrhosis who had the operation of orthotopic liver transplantation(Child-Pugh classification C 12cases,B 8 cases) were recruited in our hospital.We detected FSB,serum insulin,C peptide concentration before anesthesia,after declamping the portal vein 0min,30min,1h and 2h and Insulin index was calculated by the formula of ln[1/(FBS×insulin)].The expression of GLUT4 and PPP1Cgamma in skeletal muscle at the beginning of the operations and 30min after declamping the portal vein was also detected by the way of western-blot and Real-time PCR.The differences were studied between the two groups by statistical ways with SPSS16.0 software.Result:The serum glucose concentration after declamping of the portal vein Omin, 30min,1h and 2h was all significantly higher than that before anesthesia(p<0.01).The serum glucose came to the peak 1h and 2h after declamping of the portal vein.Although the level of serum insulin had a trend to higher than that before the operation,there was no statistical difference.To the contrary,the serum c-peptide had a trend to lower than that before the operation,there was no statistical difference.The insulin index was all significantly lower than that before operation.The skeletal Glut4 and PPPlCgamma expression detected by Western-blot and Real-time PCR existed no difference from that before operation.Conclusion:The patients with cirrhosis exist more sever insulin resistance after liver transplantation;The skeletal GLUT4 and PPPlCgamma expression detected by Western-blot and Real-time PCR exists no difference from that before transplantation. The perioperative insulin resistance in liver transplantation patients is not only associated with the preexisted insulin resistance,lower expression of skeletal PPP1Cgamma related to cirrhosis,but also the other factors related to the liver transplantation operation.