Insulin resistance in cirrhosis: evidence for a post-receptor defect

Prevalence of diabetes in liver cirrhosis: A systematic review and meta-analysis

An association between diabetes mellitus (DM) and liver cirrhosis is well-known, but estimates of the prevalence of DM in patients with liver cirrhosis vary widely. A systematic review was undertaken to determine the prevalence of DM in adult patients with liver cirrhosis. The Medline, EMBASE, and Cochrane Library databases were searched for peer-reviewed studies published in English (1979-2017) that investigated the prevalence of diabetes in adult patients with cirrhosis. Pooled estimates of prevalence of DM were determined for all eligible patients and according to aetiology and severity of liver disease. Fifty-eight studies satisfied criteria for inclusion, with 9705 patients included in the pooled prevalence analysis. The overall prevalence of DM was 31%. The prevalence of DM was highest in patients with nonalcoholic fatty liver disease (56%), cryptogenic (51%), hepatitis C (32%), or alcoholic (27%) cirrhosis. For assessing prevalence of DM as a function of severity of liver disease, evaluable data were available only for hepatitis C and hepatitis B cirrhosis. DM may be more prevalent in cirrhosis than previously thought. This has implications for prognosis and treatment in these patients.

Alterations in carbohydrate metabolism in cirrhotic patients before and after liver transplant

AIM

The main objective of this study is to demonstrate whether carbohydrate metabolism alterations identified in patients with advanced cirrhosis show any improvement after liver transplant.

METHODS

The study included 86 patients who underwent liver transplant between March 2010 and February 2011. An oral glucose tolerance test was performed before the liver transplant, and 6 and 12 months after. Beta cell function and insulin resistance were also calculated, applying formulae that use basal plasma glycaemia and insulin, and plasma glycaemia and insulin during an oral glucose tolerance test. Risk factors for pre- and post-transplant diabetes were also studied. The diagnosis of diabetes was based on an OGTT.

RESULTS

The proportion of patients with diabetes before transplant, and at month 6 and 12 after transplant were 70.9%, 48.8% and 39.2%, respectively. Compared to baseline, at month 6 the odds ratio of having diabetes was 0.39 (IC 95% [0.21, 0.73]) and at month 12 it was 0.26 (IC 95% [0.14, 0.50]). The composite insulin sensitivity index values at 6 and 12 months were 1.72 units higher (IC 95% [0.84, 2.58]) and 1.58 units higher (IC 95% [0.68, 2.44)] than baseline. A statistically significant association was found between high MELD values and high body mass index, and risk of pre-transplant diabetes (p=0.001 and p=0.033, respectively). Cirrhosis aetiology did not influence the risk of diabetes.

CONCLUSIONS

In this study, we were able to ascertain that alterations in carbohydrate metabolism typical of advanced cirrhosis improve after liver transplant. This improvement is mainly due to an improvement in insulin resistance.

Normalisation of insulin-like growth factor-I does not improve insulin action in cirrhosis

BACKGROUND & AIMS

Cirrhosis of the liver is characterised by insulin resistance and low levels of insulin-like growth factor I (IGF-I). Lack of IGF-I may contribute to this insulin resistance, as IGF-I increases insulin sensitivity. This study aimed to determine the effects of normalisation of IGF-I on insulin action in cirrhosis.

METHODS

This article is a randomised sequence-crossover placebo controlled study. Eight patients with cirrhosis and eight controls were studied following treatment with IGF-I (50 μg/kg twice daily) or saline. Insulin action, glucose utilisation and endogenous glucose production were measured during the euglycaemic hyperinsulinaemic clamp.

RESULTS

The patients with cirrhosis had normal fasting glucose level, but increased levels of insulin (P < 0.05) and C-peptide (P < 0.05). Insulin resistance resulted from a defect in glycogen synthesis, whereas insulin-mediated suppression of glucose production was unaltered. In cirrhosis, IGF-I treatment normalised free (from 0.07 ± 0.01 to 0.26 ± 0.05 μg/L) and total IGF-I (from 73 ± 6 to 250 ± 39 μg/L), whereas in controls, the IGF-I level increased into the upper physiological range (free IGF-I from 0.23 ± 0.02 to 0.61 ± 0.06 μg/L; total IGF-I from 200 ± 19 to 500 ± 50 μg/L) (all P-values < 0.05). In cirrhosis, IGF-I treatment did not change fasting glucose, insulin or C-peptide levels (P > 0.05). In the controls, insulin and C-peptide levels decreased (P < 0.05). IGF-I treatment did not improve insulin sensitivity in cirrhosis.

CONCLUSIONS

Because normalisation of IGF-I levels did not affect insulin sensitivity lack of IGF-I is unlikely to result in insulin resistance in cirrhosis. IGF-I supplementation is therefore unlikely to improve insulin action in patients with cirrhosis.

Prevalence of diabetes and incidence of angiopathy in patients with chronic viral liver disease

Patients with chronic liver disease (CLD) often develops glucose intolerance. We explored the prevalence of diabetes mellitus in viral CLD, and analyzed factors profoundly affecting the diabetic angiopathies. 229 CLD patients (124 chronic hepatitis and 105 liver cirrhosis) entered the study. The diagnosis of diabetes was made with the criteria by World Health Organization. Laboratory investigation included serum asparate aminotransferase, alanine aminotransferase, albumin, fasting blood sugar, hemoglobin A1c (HbA1c), fasting immunoreactive insulin, and HOMA-R (FBS*IRI/405). The incidence of macro- and microangiopathy were also examined. Forty (17.5%) CLD patients were diagnosed diabetes, giving a significantly higher incidence than that of general cohort (5.3%) (p<0.001). Among them, 12 (30%) had the triopathy, significantly lower than that in a matched group of diabetic patients without CLD (65%) (p<0.001). Significantly increased levels of HbA1c and HOMA-R were observed in diabetic CLD with angiopathy compared with diabetic CLD without. Incidence of diabetes was increased in viral CLD patients. The rate of diabetic angiopathies in CLD, however, was relatively low, this could be explained by low coagulability in these patients. Poor control of hyperglycemia, partly due to insulin resistance, might explain the onset of angiopathy in diabetic CLD.

Role of meal carbohydrate content for the imbalance of plasma amino acids in patients with liver cirrhosis

BACKGROUND AND AIM

Imbalance of circulating branched chain amino acids (BCAA) versus aromatic amino acids (AAA) and hyperinsulinemia are common metabolic alterations in patients with liver cirrhosis. The aim of this study was to characterize the effect of the carbohydrate component of a protein-rich mixed meal on postprandial plasma concentrations of 21 amino acids, insulin and C-peptide in patients with compensated liver cirrhosis. Furthermore, the effect of a dietary intervention on the metabolic alterations in cirrhotic patients was examined.

METHODS

Eighteen patients with cirrhosis and 12 healthy volunteers received a protein-rich meal (pork filet 200 g) with or without carbohydrates (bread 50 g, glucose 20 g). A subgroup of four cirrhotic patients received an isoenergetic (117 kJ/kg bw) carbohydrate-enriched (60%) and -restricted (20%) diet for 7 days each.

RESULTS

In the cirrhotic patients, basal plasma insulin and C-peptide concentrations were significantly elevated. The ingestion of a protein-rich meal without additional carbohydrates led to a significantly greater increase of insulin and C-peptide in the cirrhotic patients compared to controls. Postprandial increases of leucine and isoleucine were reduced, whereas those of phenylalanine were higher in cirrhotic patients. The addition of carbohydrates led to higher insulin and C-peptide plasma concentrations in cirrhotic patients. Postprandial BCAA increases were more impaired in the cirrhotic group after additional carbohydrate ingestion (46%vs 82%). After the carbohydrate-restricted diet for 7 days BCAA plasma levels increased but the BCAA/AAA ratio remained unaltered.

CONCLUSIONS

The carbohydrate content of a meal enhances reduction of BCAA plasma concentrations in clinically stable cirrhotic patients. An imbalanced BCAA/AAA ratio cannot be avoided by a carbohydrate-reduced diet alone, supporting mandatory BCAA supplementation.

The impact of diabetes mellitus on fibrosis progression in patients transplanted for hepatitis C

Despite the recognition of numerous factors for aggressive hepatitis C virus (HCV) recurrence after liver transplantation (LT) our understanding of this phenomenon is incomplete. We tested the hypothesis that diabetes mellitus (DM) was implicated. One hundred sixty-three patients undergoing primary LT for HCV from 1990 to 2004 were evaluated and biopsies were scored according to the modified Ishak score. Severe recurrence of HCV was defined as a fibrosis score > or = 4 within 6 years of LT. Risk factors assessed included recipient, donor and transplant variables. Fifty-four patients (33.1%) had a fibrosis score > or = 4 at the end of the study period. Factors associated with progression to severe fibrosis was donor age (p = 0.008) especially donor age >55 (p = 0.038, HR 2.43), pre-LT DM (p = 0.039, HR 2.68) and DM post-LT (p = 0.004, HR 3.28). The combination of receiving a liver from a donor older than 55 years and having DM post-LT was associated with an 8.38-fold risk of progression to severe fibrosis (p = 0.000124) when compared to patients not diabetic post-LT who received livers from donors aged <55 years. These data indicate that diabetic status is one of the more important variables determining the severity of HCV recurrence and is synergistic with donor age. This observation may provide an additional management opportunity to modify the impact of HCV recurrence.

Branched-chain amino acids improve glucose metabolism in rats with liver cirrhosis

It is well established that impaired glucose metabolism is a frequent complication in patients with hepatic cirrhosis. We previously showed that leucine, one of the branched-chain amino acids (BCAA), promotes glucose uptake under insulin-free conditions in isolated skeletal muscle from normal rats. The aim of the present study was to evaluate the effects of BCAA on glucose metabolism in a rat model of CCl(4)-induced cirrhosis (CCl(4) rats). Oral glucose tolerance tests were performed on BCAA-treated CCl(4) rats. In the CCl(4) rats, treatment with leucine or isoleucine, but not valine, improved glucose tolerance significantly, with the effect of isoleucine being greater than the effect of leucine. Glucose uptake experiments using isolated soleus muscle from the CCl(4) rats revealed that leucine and isoleucine, but not valine, promoted glucose uptake under insulin-free conditions. To clarify the mechanism of the blood glucose-lowering effects of BCAA, we collected soleus muscles from BCAA-treated CCl(4) rats with or without a glucose load. These samples were used to determine the subcellular location of glucose transporter proteins and glycogen synthase (GS) activity. Oral administration of leucine or isoleucine without a glucose load induced GLUT4 and GLUT1 translocation to the plasma membrane. GS activity was augmented only in leucine-treated rats and was completely inhibited by rapamycin, an inhibitor of mammalian target of rapamycin. In summary, we found that leucine and isoleucine improved glucose metabolism in CCl(4) rats by promoting glucose uptake in skeletal muscle. This effect occurred as a result of upregulation of GLUT4 and GLUT1 and also by mammalian target of rapamycin-dependent activation of GS in skeletal muscle. From these results, we consider that BCAA treatment may have beneficial effects on glucose metabolism in cirrhotic patients.

Contribution of defects in glucose uptake to carbohydrate intolerance in liver cirrhosis: assessment during physiological glucose and insulin concentrations

It is well established that subjects with liver cirrhosis are insulin resistant, but the contribution of defects in insulin secretion and/or action to glucose intolerance remains unresolved. Healthy individuals and subjects with liver cirrhosis were studied on two occasions: 1) an oral glucose tolerance test was performed, and 2) insulin secretion was inhibited and glucose was infused in a pattern and amount mimicking the systemic delivery rate of glucose after a carbohydrate meal. Insulin was concurrently infused to mimic a healthy postprandial insulin profile. Postabsorptive glucose concentrations were equal (5.36 +/- 0.12 vs. 5.40 +/- 0.25 mmol/l, P = 0.89), despite higher insulin (P < 0.01), C-peptide (P < 0.01), and free fatty acid (P = 0.05) concentrations in cirrhotic than in control subjects. Endogenous glucose release (EGR; 11.50 +/- 0.50 vs. 11.73 +/- 1.00 mumol.kg(-1).min(-1), P = 0.84) and the contribution of gluconeogenesis to EGR (6.60 +/- 0.47 vs. 6.28 +/- 0.64 mumol.kg(-1).min(-1), P = 0.70) were unaltered by cirrhosis. A minimal model recently developed for the oral glucose tolerance test demonstrated an impaired insulin sensitivity index (P < 0.05), whereas the beta-cell response to glucose was unaltered (P = 0.72). During prandial glucose and insulin infusions, the integrated glycemic response was greater in cirrhotic than in control subjects (P < 0.05). EGR decreased promptly and comparably in both groups, but glucose disappearance was insufficient at the prevailing glucose concentration (P < 0.05). Moreover, identical rates of [3-(3)H]glucose infusion produced higher tracer concentrations in cirrhotic than in control subjects (P < 0.05), implying a defect in glucose uptake. In conclusion, carbohydrate intolerance in liver cirrhosis is determined by insulin resistance and the ability of glucose to stimulate insulin secretion. During prandial glucose and insulin concentrations, EGR suppression was unaltered, but glucose uptake was impaired, which demonstrates that intolerance can be ascribed to a defect in glucose uptake, rather than abnormalities in glucose production or beta-cell function. Although insulin secretion ameliorates glucose intolerance, impaired glucose uptake during physiological glucose and insulin concentrations produces marked and sustained hyperglycemia, despite concurrent abnormalities in glucose production or insulin secretion.

Transjugular intrahepatic portosystemic shunt (TIPS) augments hyperinsulinemia in patients with cirrhosis

BACKGROUND/AIMS

Cirrhosis of the liver is characterized by glucose intolerance and hyperinsulinemia. Both increased insulin secretion and decreased insulin clearance appear to contribute to hyperinsulinemia in cirrhotic patients. A decrease in hepatic insulin extraction rate may be due either to hepatocellular dysfunction or to portosystemic shunting with decreased first-pass insulin clearance.

METHODS

To specifically address the contribution of portosystemic shunting to the pathogenesis of hyperinsulinemia in cirrhotic patients, we analyzed glycemic control and insulin levels in fasting serum in 23 cirrhotic patients before and after transjugular intrahepatic portosystemic shunt (TIPS).

RESULTS

Compared to respective values in healthy controls, C-peptide, insulin and proinsulin concentrations at baseline were increased by 340%, 120% and by 100% in cirrhotic patients (all p<0.05). In cirrhotic patients insulin levels before TIPS averaged 104+/-73 pmol/l and increased by more than 50% to 163+/-118 pmol/l after TIPS (p<0.01), whereas levels of C-peptide and proinsulin showed no significant change. Glucose and fructosamin levels also remained unchanged after TIPS.

CONCLUSION

Our data demonstrate that TIPS does not impair glycemic control in cirrhotic patients and that an increase in portosystemic shunting augments hyperinsulinemia, most likely by decreasing hepatic insulin clearance.

Association of nonalcoholic fatty liver disease with insulin resistance

BACKGROUND AND PURPOSE

Nonalcoholic fatty liver disease is frequently associated with type 2 diabetes mellitus, obesity, and dyslipidemia, but some patients have normal glucose tolerance or normal weight. We tested the hypothesis that there is an association between nonalcoholic fatty liver disease and insulin resistance that is independent of diabetes and obesity.

SUBJECTS AND METHODS

We measured anthropometric and metabolic variables in 46 patients with chronically elevated serum aminotransferase levels, "bright liver" on ultrasound scan, and normal glucose tolerance. Indexes of insulin resistance and secretion were determined using the homeostasis model assessment method. They were compared with 92 normal subjects who were matched for age and sex.

RESULTS

Patients with nonalcoholic fatty liver disease were characterized by fasting and glucose-induced hyperinsulinemia, insulin resistance, postload hypoglycemia, and hypertriglyceridemia. Insulin resistance [odds ratio (OR) = 15 per percent increase, 95% confidence interval (CI): 3.0 to 70], fasting triglyceride level (OR = 3.1 per mmol/liter increase, 95% CI: 1.1 to 8.9), 180-minute blood glucose level (OR = 4.3 per mmol/ liter decrease, 95% CI: 1.6 to 12), and average insulin concentration in response to oral glucose (OR = 3.0 per 100 pmol/liter increase, 95% CI: 1.5 to 6.2) were independently associated with nonalcoholic fatty liver disease. The exclusion of overweight and obese subjects did not change the results.

CONCLUSION

Nonalcoholic fatty liver disease is associated with insulin resistance and hyperinsulinemia even in lean subjects with normal glucose tolerance. Genetic factors that reduce insulin sensitivity and increase serum triglyceride levels may be responsible for its development.

Further evidence for an association between non-insulin-dependent diabetes mellitus and chronic hepatitis C virus infection

Non-insulin-dependent diabetes mellitus (NIDDM) may be associated with chronic hepatitis C virus (HCV) infection. This was studied further in two parts. First, 1,151 patients with HCV-related cirrhosis and 181 patients with hepatitis B virus (HBV)-related cirrhosis, well matched for age, sex, and severity of cirrhosis, were reviewed retrospectively. The prevalence of diabetes mellitus was higher in HCV-related cirrhosis (23.6%) than in HBV-related cirrhosis (9.4%; odds ratio [OR], 2.78; 95% confidence interval [CI], 1.6-4.79; P =.0002). The prevalence of diabetes mellitus was associated closely with the Child-Pugh score (OR, 3.83; 95% CI, 2. 38-6.17; P <.0001) and increasing age (OR, 1.02; 95% CI, 1.00-1.03; P =.0117). Second, 235 patients with biopsy confirmed chronic HBV or HCV underwent an oral glucose tolerance test. Only 1 of 70 patients with chronic viral hepatitis without cirrhosis was diabetic. However, 31 of 127 patients with HCV-related cirrhosis (24.4%) were diabetic compared with 3 of 38 patients with HBV-related cirrhosis (7.9%, P =.0477). The major variables associated with NIDDM were cirrhosis (OR, 14.39; 95% CI, 1.91-108; P =.0096) and male sex (OR, 4.64; 95% CI, 1. 32-16.18; P =.0161). Fasting insulin levels in 30 patients with HCV-related cirrhosis and diabetes mellitus were elevated significantly, which was consistent with insulin resistance. However, acute insulin responsiveness was reduced in all patients with HCV infection and diabetes suggesting concomitant B-cell dysfunction. This study confirms an association between HCV and NIDDM.

Human insulin receptor and insulin signaling proteins in hepatic disease

Insulin regulates hepatocellular metabolism and growth following insulin receptor (IR) autophosphorylation and activation of the intracellular adapter protein, insulin receptor substrate 1 (IRS-1). IRS-1 activates SH2 domain proteins such as Grb2, which may be vital to hepatocyte growth. To determine if these substances are abnormally expressed under pathophysiologic conditions, IR, IRS-1, Grb2 protein, and IR mRNA were studied in normal human liver (n = 10), cirrhotic liver (n = 10), and hepatocellular carcinoma (HCC) (n = 10) that had been procured during operative procedures. IR mRNA was quantified by S1-nuclease assay using a 195-bp digoxigenin-labeled IR DNA probe and normalized to the level of expression of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene. Protein concentrations were determined by immunoblot analysis following SDS-PAGE of liver homogenate samples. Labeled DNA and antibody-complexed protein were detected by chemiluminescent means and quantified by densitometric analysis (mean densitometric units +/- standard error). Similar levels of IR mRNA were observed in normal tissue, cirrhosis, and HCC. IR protein concentration was significantly greater in HCC than in normal liver (1.82 +/- 0.2 vs 1. 25 +/- 0.17; P < 0.05). IRS-1 was significantly increased in cirrhosis compared to normal liver (1.61 +/- 0.31 vs 0.86 +/- 0.21; P < 0.05). No differences were observed in Grb2 in the three tissue types. Insulin receptor overexpression, previously seen in other tumor types, may confer an insulin-mediated growth advantage in HCC if added receptors reflect functional high affinity binding sites. Although an altered mass of IRS-1 protein was not observed in HCC, an IRS-1 increase in cirrhosis may favor hepatic regeneration.

Effect of mesocaval interposition shunting and repeated sclerotherapy on blood levels of gastrointestinal regulatory peptides, amino acids, and lysosomal enzymes--a prospective randomised trial

AIMS/BACKGROUND

Patients with liver cirrhosis and portal hypertension frequently exhibit a multitude of alterations of hormones and metabolism, but the relation of these alterations to liver function, degree of blood shunting, and hepatic encephalopathy remains unclear.

METHODS

Twenty-four patients were randomised to mesocaval interposition shunt (MIS) and 21 patients to repeated sclerotherapy (ST). Several peptide hormones, amino acids and lysosomal enzymes were monitored during a 4 year follow-up period.

RESULTS

Insulin and glucagon levels were elevated in the MIS group compared to pre-therapy levels, whereas the gastrin level was significantly higher in the ST group. Pancreatic polypeptide, somatostatin and vasoactive intestinal peptide levels were not affected by either treatment. The branched chain amino acids valine, leucine and isoleucine serum levels were all elevated after ST, and the arginine, proline and tyrosine levels were higher in the MIS group at follow-up. Other amino acids were not changed, neither were the lysosomal enzymes beta-hexosaminidase nor beta-glucoronidase during this longterm follow-up.

CONCLUSION

MIS or repeated ST treatment only affected serum levels of hormones, amino acids and lysosomal enzymes to a limited extent. In this trial, the type of treatment had only a small influence on these parameters during long term follow-up.

Impaired nonoxidative glucose metabolism in patients with liver cirrhosis: effects of two insulin doses

Glucose intolerance is encountered in the majority of cirrhotic patients. This alteration has been attributed to a defective insulin-mediated glucose uptake in peripheral tissue, where nonoxidative glucose disposal seems to be chiefly impaired. To further investigate insulin action under euglycemic conditions, we studied how physiological (100 microU/mL) and pharmacological (1,000 microU/mL) plasma insulin concentrations affect whole-body insulin-mediated glucose uptake, as well as oxidative and nonoxidative glucose disposal, in cirrhotic patients and controls. To this aim, a sequential two-step insulin euglycemic clamp combined with indirect calorimetry was performed in eight cirrhotic patients and six control subjects. During the first step of the clamp, total glucose uptake was reduced by 40% in cirrhotic patients versus controls (4.42 +/- 1.39 v 7.63 +/- 1.60 mg/kg/min, P = .002). By increasing insulin to pharmacological levels, glucose disposal increased in both groups. However, the maximum rate of glucose metabolism achieved in cirrhotic patients was lower than in controls at all times (10.29 +/- 2.04 v 12.82 +/- 0.51 mg/kg/min, P = .012). Glucose oxidation was lower in cirrhotics in the basal state, but similar in both groups during insulin/glucose infusion. On the other hand, the reduced nonoxidative glucose disposal observed in cirrhotic patients was not normalized even by increasing insulin to pharmacological levels. In conclusion, in liver cirrhosis a reduced insulin sensitivity is associated with a reduced insulin responsiveness that is mainly caused by defective nonoxidative glucose disposal.

Influence of insulin on glucose metabolism and lipolysis in adipose tissue in situ in patients with liver cirrhosis

The influence of insulin on lipolysis and glucose metabolism in abdominal adipose tissue was studied in situ with the microdialysis technique during a euglycaemic insulin clamp (1 mU kg-1 min-1) in nine cirrhotic patients and 10 controls. The cirrhotic patients displayed a 50% decrease in glucose utilization rate during the clamp (P < 0.001). Dialysate glucose levels decreased similarly by 20-30%., in patients and controls, which in the presence of unchanged local blood flow in the adipose tissue in response to insulin, is at hand with a glucose uptake into the adipocytes of similar magnitude in both groups. Before and during the clamp, the arterial and dialysate levels of glycerol were higher in the patients than in the control subjects (ANOVA P = 0.001 and 0.048 in arterial blood and dialysate, respectively). In relative terms, however, insulin induced a 70% reduction of arterial and dialysate glycerol in both groups. The concentrations of lactate and pyruvate in the dialysate and blood increased in a similar way in both groups during hyperinsulinaemia. The results suggest an increased rate of lipolysis in cirrhotic patients. Insulin cannot lower it to normal, although it is still capable of achieving a relative reduction. No explanation was found in the adipose tissue to the insulin resistance to whole-body glucose utilization that was noted in the patients with cirrhosis.

Hypothalamic-pituitary adrenal function in end-stage non-alcoholic liver disease

Patients with end-stage liver disease have significant mortality often associated with intercurrent episodes of bleeding or sepsis. Intact adrenal function is essential in such situations. In order to test the hypothesis that adrenal insufficiency might be present in severe liver disease, hypothalamic-pituitary adrenal function was evaluated in patients with end-stage liver disease awaiting transplantation. The study had a prospective, open comparative design with patients restricted to those having non-alcoholic liver disease in order to avoid the confounding direct effects of alcohol on adrenocortical function. Fifty-one consecutive patients with end-stage, non-alcoholic liver disease undergoing evaluation for liver transplantation and 40 healthy controls were studied. Patients who had used corticosteroids (n = 8) or who were unable to complete the investigations (n = 5) were excluded leaving 38 patients eligible for analysis. Adrenal function was evaluated under basal conditions by single morning measurements of plasma total and free cortisol, corticosteroid-binding globulin, dehydroepiandrosterone sulfate and by adrenal stimulation indirectly using insulin-induced (0.1 U/kg, i.v.) hypoglycaemia and/or directly by adrenocorticotrophic hormone (ACTH); 250 micrograms tetracosactrin, i.v.) stimulation. Compared with healthy controls, patients with liver disease had a 64% reduction in maximal increments of plasma cortisol to indirect adrenal stimulation via insulin-induced hypoglycaemia and a 39% reduction to direct adrenal stimulation by ACTH (all P < 0.001). There was a significant negative correlation between the severity of underlying liver disease as assessed by Child-Pugh scores and peak control responses to ACTH (r = -0.647, P < 0.0001) and insulin-induced hypoglycaemia (r = -0.597, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic and hemodynamic responses of bivascularly perfused rat liver to nerve stimulation, noradrenaline, acetylcholine and glucagon in thioacetamide-induced micronodular cirrhosis

Thioacetamide-induced rat cirrhosis was characterized by single-cell necroses, fibrosis, nodular parenchyma, decrease in parenchymal volume density and an increase in liver weight per body weight so that the total amount of parenchyma was not altered. The glycogen content was normal, and signs of decompensation were not found. Isolated livers were single-pass perfused by way of both the hepatic artery and the portal vein. In the normal livers stimulation of the nerve plexuses around the hepatic artery or portal vein (7.5 Hz; 2 msec) and infusions of noradrenaline (1 mumol/L) by way of either vessel and of acetylcholine (10 mumol/L) by way of the artery only increased glucose output, reduced both portal and arterial flow and increased the intravascular pressures. Glucagon (0.5 nmol/L) augmented glucose release and had no hemodynamic effects. In chronically thioacetamide-injured livers all stimuli caused smaller metabolic alterations per gram of liver weight and decreased portal flow more and arterial flow less with stronger enhancements of intravascular pressures than in the controls. The lowered metabolic responsiveness per gram of cirrhotic liver was largely compensated by the increase in liver weight. Thus despite massive histological alterations and pronounced increases in stimulation-dependent resistances - predominantly in the portal system - cirrhotic rat livers responded in their glucose metabolism to nervous and hormonal stimuli in almost the same manner as normal livers.

Mechanism of insulin resistance in CCl4-induced cirrhosis of rats

Insulin action was studied in rats with CCl4/phenobarbital-induced cirrhosis of the liver using the euglycemic hyperinsulinemic clamp technique coupled with isotopic measurement of individual tissue glucose uptake, glycogen formation, and lipogenesis. In cirrhotic rats, dose response curves showed a reduction of insulin-stimulated total body glucose disposal of about 30%. Insulin action on tissue glucose uptake and initial phosphorylation (assessed with [3H]2-deoxyglucose) were unchanged; however, incorporation of [14C]glucose into lipids and particularly into glycogen was reduced substantially (being most pronounced in skeletal muscle and diaphragm) at maximally as well as half-maximally effective serum insulin concentrations during euglycemic clamping. At identical IV insulin infusion rates, steady-state serum insulin concentrations were elevated up to fourfold in cirrhotic animals. Antilipolytic action of insulin was unaltered. These data suggest that the principal metabolic pathway affected in insulin resistance of rats with experimental cirrhosis appeared to be insulin-stimulated glycogen formation in muscle tissues.

In vivo insulin action in hepatocellular and cholestatic liver cirrhosis

The in vivo dose response curve to insulin were studied, using an euglycemic insulin clamp technique, in 13 cirrhotic patients [8 with "hepatocellular" (HC) (nonalcoholics) and 5 with "cholestatic" (CHOL) cirrhosis] and 12 healthy controls (N). Subjects were studied in the basal state and during infusion of insulin at 3 different rates - 1, 3, 10 mU kg-1 min-1. Insulin responsiveness was similar in N and in HC, but it was 23% greater in CHOL (p less than 0.001). Insulin sensitivity was decreased in cirrhotics as compared with N but this difference was only significant (p less than 0.001) in HC. (ED50:62 + 5, 88 + 13 and 136 + 16 muu ml-1 in N, CHOL and HC respectively). Insulin clearance rate (ICR) was significantly (p less than 0.005) decreased in HC (1060 +/- 80, 996 +/- 95 and 776 +/- 128 ml sq m-1 ml-1 in N, CHOL and HC respectively. Basal hepatic glucose production (BHGP) was 39% lower in HC (p less than 0.005) and 24% lower in CHOL (p less than 0.05) than in N. Erythrocyte cholesterol phospholipid ratio was significantly elevated (p less than 0.001) in both groups of cirrhotic patients but was not correlated to specific metabolic changes described. In summary: i) intervariations in insulin dependent glucose metabolism were described in different cirrhotic groups; ii) basal hepatic glucose production and insulin clearance rate impaired in the different groups of cirrhotics; iii) the role of decreased cholesterol/phospholipid ratio on tissues glucose metabolism in cirrhotic patients should be further studied.

Effect of physiologic hyperinsulinemia on glucose and lipid metabolism in cirrhosis

Insulin secretion and insulin sensitivity were evaluated in eight clinically stable cirrhotic patients and in 12 controls. OGTT was normal in cirrhotics but plasma insulin response was increased approximately twofold compared with controls. Subjects received a three-step (0.1, 0.5, 1.0 mU/kg.min) euglycemic insulin clamp with indirect calorimetry, [6-3H]-glucose, and [1-14C]-palmitate. During the two highest insulin infusion steps glucose uptake was impaired (3.33 +/- 0.31 vs. 5.06 +/- 0.40 mg/kg.min, P less than 0.01, and 6.09 +/- 0.50 vs. 7.95 +/- 0.52 mg/kg.min, P less than 0.01). Stimulation of glucose oxidation by insulin was normal; in contrast, nonoxidative glucose disposal (i.e., glycogen synthesis) was markedly reduced. Fasting (r = -0.553, P less than 0.01) and glucose-stimulated (r = -0.592, P less than 0.01) plasma insulin concentration correlated inversely with the severity of insulin resistance. Basal hepatic glucose production was normal in cirrhotics and suppressed normally with insulin. In postabsorptive state, plasma FFA conc (933 +/- 42 vs. 711 +/- 44 mumol/liter, P less than 0.01) and FFA turnover (9.08 +/- 1.20 vs. 6.03 +/- 0.53 mumol/kg.min, P less than 0.01) were elevated in cirrhotics despite basal hyperinsulinemia; basal FFA oxidation was similar in cirrhotic and control subjects. With low-dose insulin infusion, plasma FFA oxidation and turnover failed to suppress normally in cirrhotics. During the two higher insulin infusion steps, all parameters of FFA metabolism suppressed normally. In summary, stable cirrhotic patients with normal glucose tolerance exhibit marked insulin resistance secondary to the impaired nonoxidative glucose disposal. Our results suggest that chronic hyperinsulinism may be responsible for the insulin resistance observed in cirrhosis.

Resistance to the growth-promoting and metabolic effects of growth hormone in children with chronic liver disease

Because growth failure is a frequent complication of chronic liver disease in childhood, we examined the growth hormone/insulin-like growth factor type I axis and its relationship to growth disturbances, nutritional status, and carbohydrate metabolism in nine children (2.1 to 18.6 years of age) with chronic cholestatic liver disease. Seven had cholestasis associated with splenomegaly and histologic findings of cirrhosis; two patients had Alagille syndrome. Stature was less than or equal to 15th percentile in all except the youngest subject and less than 5th percentile in five subjects. Ten-hour, nocturnal, integrated serum concentrations of growth hormone were considerably higher in patients with cholestasis than in control subjects (mean +/- SD) 9.7 +/- 3.8 vs 4.7 +/- 1.9 ng/ml; p less than 0.02). Serum concentrations of insulin-like growth hormone type I were less than 95th percentile confidence intervals for age- and sex-matched norms in five patients and at the lower limits of normal in the remaining four patients. Insulin sensitivity, determined with the minimal model intravenous glucose tolerance test, was not decreased in five patients despite elevated levels of circulating growth hormone. The estimated mean caloric and protein intake exceeded the recommended dietary allowance and the weight-for-height index was greater than 90% for six of nine patients. Triceps and subscapular skin-fold thicknesses, indicators of body fat stores, were greater than 25th percentile for five of nine and eight of nine patients, respectively, suggesting deficient lipolytic action of GH. We conclude that children with cholestatic liver disease have a resistance to the growth-promoting, diabetogenic, and lipolytic properties of growth hormone.

Effect of prolonged hyperinsulinaemia on adipocyte insulin binding and action in normal man

Prolonged moderate insulinaemia over 20 h in normal humans produces a significant reduction of in vivo insulin action. To examine the effects in man of such moderate hyperinsulinaemia on in vitro glucose metabolism, insulin-receptor binding, glucose transport and incorporation of glucose into lipid were determined in adipocytes isolated from paired gluteal fat biopsies, taken from six normal human volunteers before and 1 h after 20 h of exogenous hyperinsulinaemia (plasma insulin 38 +/- 3 mU/l). Specific binding of insulin to isolated adipocytes was not altered (6.7 +/- 0.7 versus 7.6 +/- 1.5% per 10(5) cells). Basal glucose transport of 3-O-[14C]methylglucose in the absence of insulin was reduced after hyperinsulinaemia (5.2 +/- 1.1 versus post 4.3 +/- 1.3 pmol/7 s per 10(5) cells, 0.1 less than P greater than 0.05; or expressed as percent of maximal response: 60 +/- 5 versus post 49 +/- 1%, P less than 0.05), but maximal transport (9.2 +/- 1.5 versus post 8.7 +/- 1.5 pmol/7 s per 10(5) cells) and ED50 (87 +/- 17 versus 67 +/- 15 pmol/l) were unchanged. Conversion of glucose into lipid, using 3-D-[3H]glucose, was unchanged basally, at maximal response or ED50 of the dose response curve. In conclusion, moderate 20 h in vivo hyperinsulinaemia in normal humans induces only a small change in basal vitro adipocyte glucose transport, and no change in insulin-receptor binding or in vitro incorporation of glucose into lipid. These data suggest that the adipocyte does not contribute to the impaired insulin action produced by in vivo moderate hyperinsulinaemia in man.

Alterations of glucose metabolism in chronic liver disease

The prevalence of glucose intolerance has been studied by oral glucose tolerance test in 670 patients affected by chronic liver disease. The glycometabolic status was evaluated by criteria given by WHO in 1980. Sixty-nine subjects appeared to be affected by chronic persistent hepatitis and 140 by chronic active hepatitis. In these patients the prevalence of diabetic responses (DR) did not differ much from that of the general population in our geographic area. In contrast, a markedly higher frequency of DR appeared in a cirrhotic group of 401 patients compared to non-cirrhotic subjects. The cirrhotics, divided according to different disease stages, showed a higher DR frequency in decompensated patients than in well compensated patients, the prevalence reaching 63% in the former subgroup. The coincident presence of hepatocarcinoma - documented in 60 other cirrhotic patients - does not modify the prevalence of diabetes. Other risk factors for diabetes such as age, sex, and family history have been considered. Our results suggest that: (1) all these factors seem not to play a major role in the pathogenesis of alterations of glucose metabolism in patients suffering from chronic liver disease, and therefore (2) liver cirrhosis by itself might be a risk factor in the disturbance of glucose tolerance.

Glucose and insulin metabolism in cirrhosis

Glucose intolerance, overt diabetes mellitus, and insulin resistance are characteristic features of patients with cirrhosis. Insulin secretion, although increased in absolute terms, is insufficient to offset the presence of insulin resistance. The defect in insulin-mediated glucose disposal involves peripheral tissues, primarily muscle, and most likely reflects a disturbance in glycogen synthesis. Hepatic glucose production is normally sensitive to insulin; at present, it is unknown whether hepatic glucose uptake is impaired in cirrhosis. One of the more likely candidates responsible for the insulin-resistant state is insulin itself. The hyperinsulinemia results from three abnormalities: diminished hepatic extraction, portosystemic/intrahepatic shunting, and enhanced insulin secretion.

Insulin resistance is the main determinant of impaired glucose tolerance in patients with liver cirrhosis

To clarify the pathogenesis of impaired glucose tolerance in patients with cirrhosis, several factors possibly affecting carbohydrate metabolism were studied in 12 cirrhotic patients with different blood glucose responses to an oral glucose tolerance test. Glucose levels, 120 min after the load, were inversely and significantly related to insulin sensitivity, measured by means of the euglycemic "glucose clamp" technique (r = -0.746). Basal and glucose-induced insulin secretion (insulin and C-peptide levels) only slightly correlated with glucose tolerance, which was not related to functional liver cell mass (galactose elimination), portal-systemic shunting (degree of varices at endoscopy), or maximal glucose-independent insulin secretion (peak C-peptide levels after a glucagon test). Multiple regression analysis identified insulin sensitivity and liver cell mass as the independent variables able to explain most of the variance of 120-min blood glucose (about 84%), and both of them contributed considerably to the regression. While reduced insulin sensitivity is probably the main cause of impaired glucose tolerance, the reduced hepatocellular mass only appears to modulate the degree, and therefore the clinical relevance, of this defect.

Defective glucose utilization in patients with functioning beta-cell tumors persists after tumor excision

Glucose utilization was assessed before and after operation in five patients with insulin-secreting tumors using the euglycemic clamp. Two groups of age, sex, and weight-matched controls were studied under conditions of either acute (3 h, N = 7) or chronic (48-72 h, N = 6) hyperinsulinemia (46 +/- 4 microU/mL). The rate of glucose infusion (M = mg/kg/min) required to maintain steady-state euglycemia was taken as index of glucose utilization. M was higher both in postoperative patients and in chronic controls than in preoperative patients (2.1 +/- 0.1 and 1.8 +/- 0.2 vs. 1.0 +/- 0.2, p less than 0.01), yet never achieved levels seen in acute controls (3.3 +/- 0.3, p less than 0.01). Also reported is one subject who had a predominantly proinsulin-producing tumor with little insulin secretion, who also manifested a similar defect in glucose utilization. Excision of this tumor resulted in partial reversal of the peripheral defect in glucose metabolism. In conclusion, chronic endogenous hyperinsulinemia (and hyperproinsulinemia) in humans is associated with a defect in peripheral glucose utilization that is only partially resolved 2 years after tumor removal.

Insulin binding to erythrocytes in hyperinsulinemic patients with precirrhotic hemochromatosis and cirrhosis

This study investigated insulin receptor binding (number and affinity) to erythrocytes in patients with precirrhotic hemochromatosis, patients with cirrhosis, and healthy subjects. To evaluate plasma glucose and insulin levels, an oral glucose tolerance test (OGTT) was performed in all subjects. In the fasting state, all patients exhibited normal glucose levels. Precirrhotic patients showed slight impairment of glucose tolerance while cirrhotic patients were strikingly glucose intolerant. In both patient groups, fasting plasma insulin levels were increased. Following the glucose load, plasma insulin levels were significantly enhanced in precirrhotic patients at 90 and 120 min and increased at all times in cirrhotic patients. In the postabsorptive state (in the presence of hyperinsulinemia) insulin binding and the number and affinity of insulin receptors of erythrocytes were not different in precirrhotic or cirrhotic patients when compared to controls. We conclude that studies of insulin binding on erythrocytes do not contribute to the evaluation of the pathogenesis of insulin resistance in liver disease.

Glucose intolerance and insulin resistance with aging--studies on insulin receptors and post-receptor events

The oral glucose tolerance test and immune reactive insulin level determination were performed on 100 non-obese healthy elderly and 40 young and middle-aged non-obese healthy subjects. In about 60% of the elderly an altered glucose tolerance test was found, but the insulin level was increased in the whole group of elderly subjects. This means an insulin-resistant state with aging. Further investigations were carried out to determine some possible causes of this insulin resistance. The chromium level in sera and granulocytes of elderly was significantly decreased as well as the insulin receptor numbers and the affinity to erythrocytes. In contrast, when the cyclic nucleotide levels were investigated in granulocytes under in vitro stimulation, an age-dependent increase of cAMP level was found and an unresponsiveness of cGMP, which ranged between mild and severe degrees. Concomitantly, all these changes found could contribute to the insulin resistance at the receptor and post-receptor levels with aging.

Glucose, insulin and C-peptide kinetics during intravenous glucose tolerance test in chronic liver disease

To elucidate the mechanism of glucose intolerance in chronic liver disease (CLD), the kinetics of plasma glucose, insulin and C-peptide were studied after intravenous glucose loading in patients with CLD. Fasting plasma insulin levels were higher in patients with CLD than in normal subjects. This hyperinsulinemia was attributed primarily to an increased pancreatic secretion of insulin. Patients with CLD were divided into two groups, one with normal fasting plasma glucose (FBS less than 100 mg/dl (Group I) and the other with higher FBS (Group II). In Group I, the glucose disappearance rate was normal and a brisk acute insulin response (AIR) to glucose was noted. The glucose disappearance rate in Group II was lower than that in normal subjects, and AIR to glucose was blunted. It is suggested that normal glucose tolerance in Group I patients could be interpreted as a state of compensation by hypersecretion of insulin. On the other hand, the glucose intolerance in Group II patients could be due to inadequate insulin secretion to overcome insulin resistance of CLD.

The development of diabetes mellitus and chronic liver disease in long term chelated beta thalassaemic patients

We studied 29 patients with thalassaemia major who had received intensive chelation for between 6.2 and 8.8 years. All patients had normal oral glucose tolerance tests before subcutaneous chelation therapy was introduced and 22 of 29 patients had normal liver function tests. At the end of the period of study 12 patients still had normal oral glucose tolerance (7 with normal liver function tests and 5 with chronic active hepatitis). On the other hand, 11 patients had developed impaired glucose tolerance tests (3 patients had normal liver function tests, 5 with chronic active hepatitis and 3 with cirrhosis), and 6 patients had developed frank diabetes mellitus (one with chronic active hepatitis and 5 with cirrhosis). Patients with chronic active hepatitis showed 91% positivity for one or more hepatitis B markers whilst all patients with cirrhosis were positive. Ferritin levels before subcutaneous chelation in patients with normal oral glucose tolerance tests were lower than in those patients with abnormal oral glucose tolerance or diabetes (P less than 0.05) but none had normal serum ferritin levels. In addition, a positive correlation was found between glucose area under the curve after chelation therapy and serum ferritin levels (r = 0.47, P less than 0.01). It is apparent that long term chelation therapy does not prevent the development of abnormal oral glucose tolerance in chronically transfused patients. More intensive chelation therapy is needed to prevent tissue damage. Chronic liver disease may have an important role to play in the deterioration of glucose tolerance.

Hyperinsulinaemia and insulin insensitivity: studies in subjects with insulinoma

Hepatic glucose turnover, peripheral insulin sensitivity and insulin receptor binding were measured in four subjects with insulinoma before and 3 months after surgical resection of the insulinoma. Basal hepatic glucose production, quantitated employing a primed constant infusion of tritiated glucose, was low pre-operatively (5.2 +/- 1.7 mumol X kg-1 X min-1) but returned to normal post-operatively (14.9 +/- 2.8; normal subjects 13.9 +/- 0.8 mumol X kg-1 X min-1). Paired euglycaemic dose-response curves were developed for each subject. Insulin sensitivity, expressed as a right shift of the dose-response curve (ED50), was low pre- and post-operatively. However, insulin responsiveness (Vmax) remained normal (pre-operatively 13.9 +/- 2.2, post-operatively 13.8 +/- 0.8, normal subjects 16.7 +/- 0.8 ml X kg-1 X min-1). There was no consistent pattern in monocyte or erythrocyte receptor binding before or after surgery. These data suggest that the chronic hyperinsulinaemia causes suppression of hepatic glucose production, and a state of insulin insensitivity which appears to be due to a post-receptor defect.