[Steatosis and steatohepatitis in diabetic patient]

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized condition of excess fat deposition within the liver. NAFLD includes a spectrum of liver pathology ranging from bland hepatic steatosis to steatohepatitis and cirrhosis. Nonalcoholic steatohepatitis (NASH) is an inflammatory and fibrosing condition of the liver thought to be an intermediate stage of NAFLD that may progress to endstage liver disease, liver-related death and hepatocellular carcinoma. Nonalcoholic steatohepatitis (NASH) is a common liver disease that is characterized histologically by hepatic steatosis, lobular inflammation, and hepatocellular ballooning, it can progress to cirrhosis in up to 15% of patients. There is currently no therapy that is of proven benefit for nonalcoholic steatohepatitis. The disease is closely associated with insulin resistance and features of the metabolic syndrome such as obesity (increased waist circumference), hypertriglyceridemia, and type 2 diabetes. The pathologic criteria are now well established and the diagnosis can only be made once the absence or limited use of alcohol is confirmed. In addition to insulin resistance, oxidative stress has been implicated as a key factor contributing to hepatic injury in patients with nonalcoholic steatohepatitis. Thus, both insulin resistance and oxidative stress are attractive targets for therapy in patients with this disease. Several pilot studies have provided evidence that insulin sensitizers such as thiazolidinediones and antioxidants such as vitamin E improve clinical and histologic features of nonalcoholic steatohepatitis. The medical evidence of a benefit, however, is limited, because these studies had small samples and were performed at single centers. Moreover, a recent multicenter trial showed a reduction in hepatic steatosis but no improvement in markers of cell injury after a year of rosiglitazone therapy. The value of these remains uncertain. Until now the best trial was done by Sanyal, who studied 240 patients divided into 3 groups (pioglitazone versus vitamin E versus placebo)--multicenter, randomized, double-blind clinical trial in non-diabetics.

[Diabetes mellitus and ischemic heart disease]

Diabetes mellitus (DM) is closely associated with cardiovascular (CV) diseases. These are the main cause of death in patients not only with type 2 but also type 1 diabetes. Apart from the traditional risk factors such as arterial hypertension, dyslipidemia and obesity, hyperglycaemia is an independent risk factor for the development of ischemic heart disease (IHD). Long-term hyperglycaemia leads to vascular damage through several mechanisms. These include oxidative stress, formation of advanced glycation end products, activation of the nuclear factor kappa B and decreased production of nitrogen monoxide (NO). Insulin resistance is believed to have an important bearing on pathogenesis of IHD in type 2 diabetes (DM2) patients. The course of IHD in diabetic patients is usually more complicated. Direct percutaneous coronary intervention (PCI) is the gold standard in the treatment of myocardial infarction (MI) in diabetic as well as non-diabetic patients. Drug-eluting stents, associated with fewer reocclusions, have also proved useful. In addition to drug-eluting stent implantation, surgical revascularization, preferably utilizing internal thoracic artery, is a suitable technique in patients without acute coronary syndrome indicated for an intervention. Conservative approach should be applied in less severely affected patients. IHD prevention should include appropriate control of arterial hypertension, dyslipidemia and weigh reduction. Diabetes treatment should be managed individually and with respect to the potential risk of hypoglycaemia in high-risk patients with longer duration of diabetes and known CV disease. Newly diagnosed type 2 diabetes patients should from the onset be treated with metformin and tight compensation should be aimed for with target value for glycated haemoglobin of less than 4.5% (IFCC methodology). Evidence exists that this approach may significantly reduce the CV risk. Intensified insulin regimen is the most suitable treatment approach for the type 1 diabetes patients also with respect to microvascular and macrovascular complication prevention. Treatment of hyperglycaemia is one of the set of measures that may contribute to CV risk reduction in diabetic patients.

[Metabolic syndrome and the liver (NAFLD/NASH)]

Metabolic syndrome (MS) is one of the most prevalent disease states in the so-called developed countries and is closely associated with the incidence of cardiovascular as well as other diseases. Predominant sign is the abdominal type of obesity with increased visceral fat mass and the associated insulin resistance. Glucose metabolism disorder, dyslipidemia and arterial hypertension are other important attributes. Metabolic syndrome is also closely associated with the liver steatosis, mostly benign and reversible liver disease. Nevertheless, uncomplicated steatosis may, under certain conditions, progress to inflammation and the disease may, through the stage of NASH (nonalcoholic steatohepatitis) and liver fibrosis, result in liver cirrhosis and hepatocellular carcinoma. Anglo-Saxon literature uses the term NAFLD (non-alcoholic fatty liver disease) to refer to these various stages ofthe liver disease (uncomplicated liver steatosis, steatohepatitis, fibrosis and cirrhosis). While simple steatosis is not dangerous for the patient, NASH is the sign of developing cirrhosis. Etiopathogenesis of NASH features identical characteristics as etiopathogenesis of insulin resistance and metabolic syndrome. Even though liver biopsy remains the gold standard in the diagnosis, new diagnostic approaches are emerging that could be useful in distinguishing simple steatosis from NASH. Therapy includes lifestyle changes, insulin resistance-reducing medication (also useful in the treatment of type 2 diabetes) with a range of other agents under development. In the meantime, randomized double-blind placebo-controlled studies with histological proof of the results are still lacking. A range of unresolved issues remains with regards to etiopathogenesis as well as diagnosis and treatment of NAFLD and NASH.

[Effect of transjugular portosystemic shunt on insulin resistance]

Patients with cirrhosis of the liver suffer from hyperinsulinaemia and a certain degree of insulin resistance. More frequently than in the rest of the population they have diabetes. Transjugular intrahepatic portosystemic shunts (TIPS) as a therapeutic method in complications of portal hypertension lead to rapid haemodynamic changes in the liver. The objective of the submitted work was to assess whether TIPS has an impact on insulinaemia and whether it influences insulin resistance in patients with cirrhosis of the liver.

GROUP AND METHODS

The authors evaluated a group of 22 patients with cirrhosis of the liver (10 diabetics and 12 subjects without diabetes) indicated for TIPS. They investigated the insulin and C-peptide concentration in blood obtained by catheterization from the hepatic and portal vein before and after TIPS and in the peripheral blood before TIPS, 1 hour, 1 day, 1 week and 1 month after TIPS. The insulin resistance was examined by the method of the hyperinsulin euglycaemic clamp (HEC) before TIPS, 1 day, 1 week, and 1 month after TIPS. The levels of C-peptide and insulin were assessed by the IRMA method. The blood sugar level in HEC was measured by means of a Hemocue apparatus. The results were evaluated by the non-parametric Wilcoxon test for two dependent samples.

RESULTS

Both groups (diabetics and non-diabetics) were comparable as to age, sex, etiology of liver cirrhosis and indication for TIPS. After introduction of TIPS a change of insulin clearance occurred (p = 0.01) and a change of the insulin level in the hepatic vein immediately after TIPS (p = 0.02). Insulin clearance before TIPS was 37-90% (median 54%) and after TIPS it declined to 0-79% (median 38%) (p = 0.01). Already 1 hour after the operation the authors observed a rise of the insulin level in peripheral blood as compared with baseline values (p = 0.002). Statistically significant hyperinsulinaemia persisted one month after TIPS (p = 0.005). Values of C-peptide did not change significantly in time, neither in the hepatic vein nor in the peripheral blood. On examination of IR no statistically significant changes occurred after TIPS. On evaluation of different groups of diabetics and non-diabetics the IR was more marked in patients with DM (mean M = 1.7 mg/kg/min.) than in patients without DM (3.7 mg/kg/min.) (p = 0.03). The authors did not record significant changes of IR in time in different groups. Compensation of DM was not influenced by TIPS. The fasting blood sugar levels before TIPS and 1 month after TIPS were comparable.

CONCLUSION

After TIPS a rise of the insulin level in peripheral blood occurred due to the reduced insulin clearance in the liver. Despite hyperinsulinaemia which persisted for one month after the operation, the insulin resistance did not deteriorate. Compensation of diabetes was not affected by TIPS.