Glucose intolerance in liver cirrhosis

Skeletal muscle protein turnover responses to parenteral nutrition in patients with alcoholic liver cirrhosis and sarcopenia

Alcoholic liver cirrhosis (ALC) is accompanied by sarcopenia. The aim of this study was to investigate the acute effects of balanced parenteral nutrition (PN) on skeletal muscle protein turnover in ALC. Eight male patients with ALC and seven age- and sex-matched healthy controls were studied for 3 h of fasting followed by 3 h of intravenous PN (SmofKabiven 1,206 mL: amino acid = 38 g, carbohydrates = 85 g, and fat = 34 g) 4 mL/kg/h. We measured leg blood flow and sampled paired femoral arteriovenous concentrations and quadriceps muscle biopsies while providing a primed continuous infusion of [ring-2d5]-phenylalanine to quantify muscle protein synthesis and breakdown. Patients with ALC exhibited shorter 6-min walking distance (ALC: 487 ± 38 vs. controls: 722 ± 14 m, P < 0.05), lower hand-grip strength (ALC: 34 ± 2 vs. controls: 52 ± 2 kg, P < 0.05), and computed tomography (CT)-verified leg muscle loss (ALC: 5,922 ± 246 vs. controls: 8,110 ± 345 mm2, P < 0.05). Net leg muscle phenylalanine uptake changed from negative (muscle loss) during fasting to positive (muscle gain) in response to PN (ALC: -0.18 ± +0.01 vs. 0.24 ± 0.03 µmol/kg muscle·min-1; P < 0.001 and controls: -0.15 ± 0.01 vs. 0.09 ± 0.01 µmol/kg muscle·min-1; P < 0.001) but with higher net muscle phenylalanine uptake in ALC than controls (P < 0.001). Insulin concentrations were substantially higher in patients with ALC during PN. Our results suggest a higher net muscle phenylalanine uptake during a single infusion of PN in stable patients with ALC with sarcopenia compared with healthy controls.NEW & NOTEWORTHY Muscle protein turnover responses to parenteral nutritional (PN) supplementation have not previously been studied in stable alcoholic liver cirrhosis (ALC). We applied stable isotope tracers of amino acids to directly quantify net muscle protein turnover responses to PN in sarcopenic males with ALC and healthy controls. We found a higher net muscle protein gain in ALC during PN, thereby providing the physiological rationale for future clinical trials of PN as a potential countermeasure to sarcopenia.

Cannabis sativa L. (var. indica) Exhibits Hepatoprotective Effects by Modulating Hepatic Lipid Profile and Mitigating Gluconeogenesis and Cholinergic Dysfunction in Oxidative Hepatic Injury

Cannabis sativa L. is a crop utilized globally for recreational, therapeutic, and religious purposes. Although considered as an illicit drug in most countries, C. sativa until recently started gaining attention for its medicinal application. This study sought to investigate the hepatoprotective effect of C. sativa on iron-mediated oxidative hepatic injury. Hepatic injury was induced ex vivo by incubating hepatic tissues with Fe2+, which led to depleted levels of reduced glutathione, superoxide dismutase, catalase and ENTPDase activities, triglyceride, and high-density lipoprotein-cholesterol (HDL-C). Induction of hepatic injury also caused significant elevation of malondialdehyde, nitric oxide, cholesterol, and low-density lipoprotein-cholesterol (LDL-C) levels while concomitantly elevating the activities of ATPase, glycogen phosphorylase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, amylase, and lipase. Treatment with the hexane, dichloromethane (DCM), and ethanol extracts of C. sativa leaves significantly (p < 0.05) reversed these levels and activities to almost near normal. However, there was no significant effect on the HDL-C level. The extracts also improved the utilization of glucose in Chang liver cells. High-performance liquid chromatography (HPLC) analysis showed the presence of phenolics in all extracts, with the ethanol extract having the highest constituents. Cannabidiol (CBD) was identified in all the extracts, while Δ-9-tetrahydrocannabinol (Δ-9-THC) was identified in the hexane and DCM extracts only. Molecular docking studies revealed strong interactions between CBD and Δ-9-THC with the β2 adrenergic receptor of the adrenergic system. The results demonstrate the potential of C. sativa to protect against oxidative-mediated hepatic injury by stalling oxidative stress, gluconeogenesis, and hepatic lipid accumulation while modulating cholinergic and purinergic activities. These activities may be associated with the synergistic effect of the compounds identified and possible interactions with the adrenergic system.

Late-Evening Snack with Branched-Chain Amino Acid-Enriched Nutrients Does Not Always Inhibit Overt Diabetes in Patients with Cirrhosis: A Pilot Study

Cirrhosis patients often have abnormal glucose metabolism. We investigated the effects of a late-evening snack (LES) with branched-chain amino acid-enriched nutrients (BCAA-EN) on glucose metabolism in cirrhosis patients. LES with BCAA-EN was administered for 1 week in 13 patients with cirrhosis and hypoalbuminemia. Blood glucose (BG) levels were measured every 15 min. The patients were divided into two groups based on BG levels: group 1 (G1, n = 11): nocturnal BG levels <200 mg/dL and group 2 (G2, n = 2): nocturnal BG levels ≥200 mg/dL. G1 had nocturnal BG levels <200 mg/dL, whereas G2 had nocturnal BG levels ≥200 mg/dL. The average BG levels did not significantly change after BCAA-EN administration in G1 (before 91.9 ± 29.0 mg/dL; after 89.0 ± 24.3 mg/dl). However, the average BG levels significantly increased after BCAA-EN administration in G2 (before 153.6 ± 43.3 mg/dL; after 200.9 ± 59.7 mg/dL) (p < 0.01). The glycated albumin level (16.6 ± 0.9% vs. 16.2 ± 2.1%), fasting immunoreactive insulin (F-IRI) level (53.9 ± 34.0 μU/mL vs. 16.5 ± 11.0 μU/mL), and homeostasis model assessment of insulin resistance (HOMA-IR) score (17.85 ± 10.58 vs. 4.02 ± 2.59) were significantly higher in G2 than in G1 (p < 0.05, p < 0.05, and p < 0.01, respectively). The quantitative insulin sensitivity check indices (0.32 ± 0.03 vs. 0.27 ± 0.02) were significantly higher in G1 than in G2 (p < 0.01). One patient in G2 was obese and had type 2 diabetes. The other patient was obese and had a high HOMA-IR score and F-IRI level. A LES with BCAA-EN does not inhibit overt diabetes in most cirrhosis patients. However, close attention should be paid to fluctuations in BG levels in cirrhosis patients who present with obesity and severe insulin resistance.

Selective insulin resistance in hepatocyte senescence

Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence.

Effects of late evening snack including branched-chain amino acid on the function of hepatic parenchymal cells in patients with liver cirrhosis

AIM

  A late evening snack (LES) improves protein-energy malnutrition due to overnight starvation and the catabolic state in patients with liver cirrhosis. Our aim was to examine whether LES including a branched-chain amino acid (BCAA) could maintain hepatic reserve and the function of hepatic parenchymal cells in patients with liver cirrhosis, including those in the early stage of disease.

METHODS

  Seventeen patients with liver cirrhosis received LES with a BCAA-enriched nutrient mixture. During the study period, each patient was instructed on energy and protein intake. Indicators of liver function measured at 6 months included maximum asialoscintigraphic removal (Rmax: indicator of total liver receptors), asialoscintigraphic imaging grade, serum albumin, ammonia, tyrosine and BTR (molar ratio of branched-chain amino acids to tyrosine).

RESULTS

  Serum albumin levels, BTR and tyrosine levels of the 17 patients were significantly improved after nutrient treatment. In patients with Rmax of 0.2 or higher, serum albumin level and tyrosine level were significantly improved.

CONCLUSION

  LES with BCAA-enriched nutrient therapy can improve protein malnutrition in patients with liver cirrhosis, and is more useful in the early stages of liver cirrhosis in improving hepatic parenchymal cell mass.

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.

[Carbohydrate metabolism dysregulation in cirrhosis: pathophysiology, prognostic impact and therapeutic implications]

The liver plays a key-role in carbohydrates metabolism. Glucose intole-rance, overt diabetes mellitus and insulin resistance are characteristic features of patients with cirrhosis. Central hyperinsulinemia and peripheral insulin-resistance are the main explanations for the high prevalence of diabetes in patients with cirrhosis. On the other hand, type 2 diabetes is associated with a wide spectrum of liver diseases ranging from nonalcoholic fatty liver to cirrhosis and hepatocellular carcinoma. Carbohydrate metabolism abnormalities are a major aggravating risk factor in cirrhosis. Diabetes is also an independent negative prognostic factor in cirrhotic patients. This leads to specific diagnostic procedures and therapeutic issues. Patients with diabetes and liver disease frequently need insulin treatment. The presence of liver disease makes the treatment of diabetes complex, and additional research is needed to determine the best treatment strategies in these patients.

Zinc and the liver: an active interaction

Zinc is an essential trace element, exerting important antioxidant, anti-inflammatory, and antiapoptotic effects. It affects growth and development and participates in processes such as aging and cancer induction. The liver is important for the regulation of zinc homeostasis, while zinc is necessary for proper liver function. Decreased zinc levels have been implicated in both acute and chronic liver disease states, and zinc deficiency has been implicated in the pathogenesis of liver diseases. Zinc supplementation offers protection in experimental animal models of acute and chronic liver injury, but these hepatoprotective properties have not been fully elucidated. In the present review, data on zinc homeostasis, its implication in the pathogenesis of liver diseases, and its effect on acute and chronic liver diseases are presented. It is concluded that zinc could protect against liver diseases, although up to now the underlying pathophysiology of zinc and liver interactions have not been defined.

Restoration of the glycogen-forming function of hepatocytes in rats with liver cirrhosis is facilitated by a high-carbohydrate diet

Using cytofluorimetric and biochemical methods, the content of glycogen and its labile and stable fractions, as well as activities of glucose-6-phosphatase (EC 3.1.3.9), glycogen phosphorylase (EC 2.4.1.1) and glycogen synthase (EC 2.4.1.11) were determined in the rat liver for 6 months after chronic poisoning of the animals with CCl4 and then at 1, 3, and 6 months after the end of the poisoning. One group of rats was given a standard diet, the other, a high-carbohydrate diet. The 6-month long chronic intoxication with CCl4 was shown to produce development of typical liver cirrhosis characterized by a 2·8-fold increase in the total glycogen content in hepatocytes as compared with normal cells, by a fall in the glycogen labile fraction (from 85 to 53 % of the total glycogen) as well as by decreases in the activities of glycogen phosphorylase and glucose-6-phosphatase by 25 and 82% respectively. The structural rehabilitation occurred faster and more completely at the cellular level than at the tissue level. Functional variables of the cirrhotic liver tissue also recovered, after cessation of poisoning, faster and more completely than the liver structure at the tissue level: glycogen levels in hepatocytes fell dramatically, the labile: stable glycogen fraction ratio recovered completely, and the activity of glycogen phosphorylase rose to the level characteristic of the normal liver. Use of the high-carbohydrate diet promoted a somewhat faster and more complete recovery of hepatic structure and function.

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.

Effects of the 2-ethylthiobenzimidazole hydrobromide (bemithyl) on carbohydrate metabolism in cirrhotic rat liver

The effect of the actoprotector bemithyl (2-ethylthiobenzimidazole hydrobromide) on the content of glycogen and activities of glycogen synthase, glycogen phosphorylase, and glucose-6-phosphatase was studied in the cirrhotic rat liver. The content of glycogen and its fraction was determined by a cytofluorimetric method (Kudryavtseva et al. 1974). It has been shown that in cirrhosis the content of total glycogen in hepatocytes increases about 3 times and the content of its stable fraction increases 7.5 times. The activity of glucose-6-phosphatase fell to a level as low as 25% of normal. Activities of glycogen synthase and glycogen phosphorylase in the cirrhotic liver did not differ from normal. In the cirrhotic liver, bemithyl produced a decrease of the total glycogen content which was associated with a decrease of the glycogen synthase activity and an increase of the glucose-6-phosphatase and glycogen phosphorylase activities. Thus, the results of our studies indicate a favorable effect of bemithyl on the cirrhotic liver.

Biochemical abnormalities during the progression of hepatic fibrosis induced by dimethylnitrosamine

OBJECTIVES

The pathogenesis of hepatic fibrosis is accompanied with several biochemical and metabolic abnormalities. To obtain more information about the alteration of biochemical and metabolic parameters during alcoholic liver fibrosis, we have monitored the changes of certain important biochemical compounds in experimentally induced hepatic fibrosis.

DESIGN AND METHODS

The liver injury was induced in adult male albino rats by using dimethylnitrosamine (DMN) in doses of 1 mg/100 g body weight. Total collagen, total protein, cholesterol, lipid peroxides, glucose, urea, and inorganic phosphorus were monitored in liver and blood/serum samples on Days 0, 7, 14, and 21 after the start of DMN administration. Serum insulin levels were assayed by radioimmunoassay. The serum and urinary levels of hydroxyproline, uric acid, and creatinine were also monitored.

RESULTS

The total collagen content in the liver was increased about 4-fold by Day 21 after the start of DMN administration. A significant increase was observed in lipid peroxide levels in both liver and blood samples. Although inorganic phosphorus level decreased in both serum and liver tissue, cholesterol was lowered only in the serum. Increased serum insulin level with impaired glucose tolerance was observed after 21 days. Serum hydroxyproline level increased throughout after the start of DMN administration. The urinary excretion of hydroxyproline was also significantly increased with a striking elevation on Day 7. Elevated uric acid levels were recorded in serum and urine samples during the latter periods of DMN treatment. No alteration was observed in blood urea and creatinine levels.

CONCLUSIONS

The results of the present investigation demonstrated important alterations in metabolic parameters and biochemical abnormalities during experimentally induced liver damage. All alterations are compatible with the deterioration of liver functions during the pathogenesis of hepatic fibrosis.

Daily pattern of energy metabolism in cirrhosis

The daily pattern of energy expenditure and the oxidation rates of carbohydrates, fats, and protein were evaluated by indirect calorimetry in 18 control subjects (Group 1) and 34 cirrhotic patients who were divided into Groups 2a and 2b showing indocyanin green retention rates at 15 min of <30% and 30% or more, respectively. The ratio of resting energy expenditure to basal energy expenditure (%REE) was higher in the cirrhotic patients than in the controls at 8:30 AM and 2:30 PM. The oxidation rates of carbohydrates and fats under fasting conditions in Group 2b patients were respectively lower, and higher than in Group 1 and 2a patients. After the subjects ate, glucose became the substrate preferentially metabolized, and the proportion of fat metabolized was reduced from 82.9+/-5.1% to 43.9+/-21.9% and from 70.7+/-14.1% to 46.8+/-13.9% in the patients with advanced and less advanced cirrhosis, respectively, and from 59.4+/-27.2% to 48.4+/-18.5% in the controls. The fasting concentrations of non-esterified fatty acids in Group 2b were also significantly higher than those in the Group 1 and Group 2a patients. After eating, these concentrations fell and reached similar levels in the patients and controls. These data indicated that the patients with cirrhosis developed the catabolic state of starvation in the morning because of a lack of glycogen stores. Therefore, frequent meal supplementation to prevent early-onset starvation and energy deficiency may be advisable in such patients to maintain a well-nourished condition.

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.

Long-term (12 months) treatment with an anti-oxidant drug (silymarin) is effective on hyperinsulinemia, exogenous insulin need and malondialdehyde levels in cirrhotic diabetic patients

BACKGROUND/AIMS

Several studies have demonstrated that diabetic patients with cirrhosis require insulin treatment because of insulin resistance. As chronic alcoholic liver damage is partly due to the lipoperoxidation of hepatic cell membranes, anti-oxidizing agents may be useful in treating or preventing damage due to free radicals. The aim of this study was to ascertain whether long-term treatment with silymarin is effective in reducing lipoperoxidation and insulin resistance in diabetic patients with cirrhosis.

METHODS

A 12-month open, controlled study was conducted in two well-matched groups of insulin-treated diabetics with alcoholic cirrhosis. One group (n=30) received 600 mg silymarin per day plus standard therapy, while the control group (n=30) received standard therapy alone. The efficacy parameters, measured regularly during the study, included fasting blood glucose levels, mean daily blood glucose levels, daily glucosuria levels, glycosylated hemoglobin (HbA1c) and malondialdehyde levels.

RESULTS

There was a significant decrease (p<0.01) in fasting blood glucose levels, mean daily blood glucose levels, daily glucosuria and HbA1c levels already after 4 months of treatment in the silymarin group. In addition, there was a significant decrease (p<0.01) in fasting insulin levels and mean exogenous insulin requirements in the treated group, while the untreated group showed a significant increase (p<0.05) in fasting insulin levels and a stabilized insulin need. These findings are consistent with the significant decrease (p<0.01) in basal and glucagon-stimulated C-peptide levels in the treated group and the significant increase in both parameters in the control group. Another interesting finding was the significant decrease (p<0.01) in malondialdehyde/levels observed in the treated group.

CONCLUSIONS

These results show that treatment with silymarin may reduce the lipoperoxidation of cell membranes and insulin resistance, significantly decreasing endogenous insulin overproduction and the need for exogenous insulin administration.

Pathogenesis of glucose intolerance and diabetes mellitus in cirrhosis

Glucose intolerance and diabetes mellitus are both prevalent in cirrhosis, yet the pathogenesis of impaired glucose metabolism remains unknown. Therefore insulin secretion (hyperglycemic clamp, +125 mg/dl), insulin sensitivity (euglycemic hyperinsulinemic insulin clamp, +10 microU/ml and +50 microU/ml), whole-body glucose oxidation (indirect calorimetry) and glucose turnover ([6,6-2H2]glucose isotope dilution) were evaluated in a homogenous group of cirrhotic patients with glucose intolerance (n = 7) or frank diabetes mellitus (n = 6). The results were compared with those obtained in control subjects (n = 8). In glucose-intolerant patients, whole-body glucose uptake (mainly reflecting glucose utilization by muscle) was significantly impaired in patients during both insulin infusions as a result of decreased stimulation of the two major intracellular pathways of glucose disposal--nonoxidative glucose disposal (i.e., glycogen synthesis) and glucose oxidation. Hepatic glucose production was normal in the basal state and was normally suppressed during stepwise insulin infusion (by 65% and 85%, respectively, p = NS vs. controls). Hyperglycemia-induced increases of plasma C-peptide concentrations were comparable to those in controls (p = NS). In diabetic patients, insulin-mediated glucose uptake was significantly reduced, mainly because of impaired non-oxidative glucose disposal. Glucose oxidation appeared to be reduced, too. Hepatic glucose production was significantly increased in the basal state (3.03 +/- 0.24 vs. 2.34 +/- 0.10 mg/kg min, p < 0.02) and during insulin infusion (+50 microU/ml: 0.67 +/- 0.17 vs. 0.13 +/- 0.08 mg/kg min, p < 0.05) compared with that in controls. Both the first and second phases of beta-cell secretion were significantly reduced in response to steady-state hyperglycemia (both p < 0.01 vs. control values). In conclusion, glucose intolerance in cirrhosis results from two abnormalities that occur simultaneously: (a) insulin resistance of muscle and (b) an inadequate response (even when comparable to that of controls) of the beta-cells to appropriately secrete insulin to overcome the defect in insulin action. Diabetes mellitus in insulin-resistant cirrhotic patients develops as the result of progressive impairment in insulin secretion together with the development of hepatic insulin resistance leading to fasting hyperglycemia and a diabetic glucose tolerance profile.

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.

Leucine and phenylalanine kinetics in compensated liver cirrhosis: effects of insulin

BACKGROUND

The pathogenesis of the altered ratio of branched-chain amino acid to aromatic amino acid concentration in liver cirrhosis is poorly known. We explored the possible link between altered amino acid concentrations and kinetics in cirrhosis.

METHODS

Post-absorptive leucine and phenylalanine rates of appearance (Ra) and their response to insulin were studied in patients with compensated, nondiabetic cirrhosis and in controls.

RESULTS

In the cirrhotics, concentration of postabsorptive phenylalanine was greater and that of alpha-ketoisocaproate lower than in controls, whereas concentration of leucine was comparable. Leucine Ra was lower, phenylalanine Ra was greater, and the ratio of leucine Ra to phenylalanine Ra was markedly decreased (P < 0.001) in patients vs. controls (2.40 +/- 0.23 vs. 3.67 +/- 0.19, respectively). During an euglycemic-hyperinsulinemic clamp, glucose disposal was reduced and leucine Ra was suppressed more profoundly in cirrhotics than in controls, whereas suppression of phenylalanine Ra was comparable.

CONCLUSIONS

In compensated liver cirrhosis, postabsorptive phenylalanine Ra is increased with respect to leucine Ra, suggesting the existence either of altered amino acid pools and/or transport or of abnormally sequenced proteins and/or peptides. Insulin resistance is restricted to glucose, but not to amino acid metabolism.

Modulation of insulin secretion by hepatic vagotomy in cirrhotic rats

There is evidence that glucose sensors and arginine sensors are present in the hepato-portal system and exert a reflex regulation of the pancreatic neuroendocrine system in normal rats. To investigate the function of these sensor systems in liver cirrhosis, we examined the effect of hepatic vagotomy on plasma glucose and insulin concentrations after intraperitoneal (IP) injection of glucose or L-arginine in carbon tetrachloride (CCl4)-induced cirrhotic rats. After IP glucose injection, hepatic vagotomy decreased plasma insulin with elevation of plasma glucose in control rats; however, in cirrhotic rats, this procedure did not affect either plasma glucose or insulin concentrations. After IP arginine injection, hepatic vagotomy increased plasma insulin and reduced plasma glucose in control rats, although in cirrhotic rats, this procedure did not affect plasma glucose but did increase plasma insulin concentrations. These results suggest that function of the glucose sensor in CCl4-induced cirrhotic rats is disturbed, although that of the arginine sensor is retained.

Early postprandial energy expenditure and macronutrient use after a mixed meal in cirrhotic patients

The effect of meal ingestion (9 kcal/kg of body weight, 53% carbohydrate, 30% fat, 17% protein, as a liquid formula) on energy expenditure and oxidation rate of carbohydrate, fat, and protein was assessed by indirect calorimetry and urinary nitrogen excretion before and for 3 hours after eating in stable cirrhotic patients and control subjects of comparable age. Postprandial modifications of substrate and hormone levels were also studied. Compared with basal values, the mean +/- SD resting energy expenditure during the first 3 hours after meal ingestion increased similarly in cirrhotic patients (+0.32 +/- 0.12 kcal/min) and control subjects (+0.31 +/- 0.08 kcal/min). Dietary induced thermogenesis was equivalent to 10% of the energy contained in the meal in both groups. Before eating, the carbohydrate oxidation rate was lower and fat oxidation higher in cirrhotic patients than in the control subjects. After eating, glucose oxidation increased whereas fat and protein oxidation rates were reduced in both groups. As a consequence the amount of fat oxidized in the postprandial period remained higher in cirrhotic patients than in the control subjects. After meal ingestion, serum glucose levels increased whereas plasma free fatty acid and glycerol levels decreased in both groups. The substrates, however, remained significantly higher in cirrhotic patients than in control subjects, despite the higher postprandial insulin increment in the patients group, thus suggesting the presence of insulin resistance. Because the postprandial glucose oxidation rate was normal, the low insulin-mediated glucose uptake observed in cirrhotic patients seems to reflect a defect in the nonoxidative disposal of the glucose ingested.(ABSTRACT TRUNCATED AT 250 WORDS)

The thermogenic and metabolic effects of food in liver cirrhosis: consequences on the storage of nutrients and the hormonal counterregulatory response

The thermogenic effect of food and the rates of oxidation and storage of nutrients were evaluated by indirect calorimetry in 10 cirrhotic patients and seven normal controls for a 6-hour period, after they had consumed a standard meal supplying 15 kcal/kg body weight with 15%, 30%, and 55% protein, fat, and carbohydrate calories, respectively. Although the thermogenic response to food was not significantly lower in patients than in controls (51.6 +/- 13.5 v 72.2 +/- 8.8 kcal/6 h), patients exhibited a delayed and blunted increment of energy expenditure after the meal intake (P less than .025). The greater part of the glucose load was oxidized in patients (70.2 +/- 3.9% v 50.4 +/- 3.9% in controls; P less than .01), suggesting a defective glucose storage as glycogen. This result could be related to insulin resistance, which was evidenced by a large increase in glucose and insulin levels after the meal intake in patients (P +/- .001). Conversely, lipid oxidation was sharply reduced and de novo lipogenesis occurred in patients, so that the rate of lipid storage was increased. The profiles of circulating levels of catecholamines, thyroid hormones (free thyroxine [FT4] and triiodothyronine [T3]), and glucagon were assayed during the test. Norepinephrine and glucagon levels remained higher in patients throughout the test (P less than .001), whereas thyroid hormones stayed in the same range in the two groups. After an initial increase, glucose levels decreased sharply, inducing an activation of counterregulatory hormones, glucagon, and notably, epinephrine, for which the increment was correlated with the decrease of glucose (r = -.917; P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic clearance of a fat emulsion containing medium-chain triglycerides in cirrhotic patients

Medium-chain triglycerides (MCTs) may be advantageous in cirrhotic patients, but data on the clearing capacity are lacking. Intravenous fat tolerance test (IVFTT) was performed on 28 cirrhotic patients (Child's A, n = 9; Child's B, n = 13; Child's C, n = 6) to determine the clearance rate of Lipofundin MCT 20%, which contains a physical mixture of MCT and long-chain triglycerides (LCT). The mean fractional elimination rate (k2) of MCT/LCT physical blend in the cirrhotic patients (7.72%/min) was comparable with that of the healthy control subjects (n = 9, k2 = 5.43%/min). Significantly higher serum free fatty acid (FFA) levels were found in the cirrhotic patients during IVFTT. The difference could be accounted for by their higher basal levels. In all patients, serum FFA concentrations returned to basal value at the end of 1 hour. Prompt appearance of glycerol and beta-hydroxybutyrate was seen during IVFTT, indicating that hydrolysis of triglycerides and release of ketone bodies from the liver were rapid. It was concluded that the ability to eliminate MCT/LCT physical blend was not impaired in the cirrhotic patients.

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.

The effect of an eucaloric high carbohydrate diet on circulating levels of glucose, fructose and non-esterified fatty acids in patients with cirrhosis

Twelve cirrhotic patients and six controls were fed an eucaloric high carbohydrate (CHO) diet for 3 days. Fasting serum triglyceride (TG), non-esterified fatty acids (NEFA), glucose, insulin and glycerol were estimated daily. On the 3rd day of the study we measured NEFA, glucose, insulin, and fructose every 45 min from 07:45 h until 19:45 h, and then every 4 h until 07:45 h the next day. The patients were divided into two groups of six on the basis of plasma lecithin-cholesterol acyltransferase (LCAT) activity: group A cirrhotics (with good liver function--LCAT activity: 40.6-65.7 nmol.ml-1.h-1; mean 48.5), and group B (poor liver function--LCAT: 23.7-32.3; mean 27.4). On the high CHO diet there was an increase in the fasting serum TG with a peak after 2 or 3 days. The increase in serum TG in controls was greater (p less than 0.01) than in either group of cirrhotics. In the controls and in group A most of the extra TG was carried in VLDL; in group B only 39% of the TG increment was found in VLDL. Fasting NEFA fell with 3 days of CHO feeding in the control group (p less than 0.01); they were unchanged in group A, and rose in group B to a significantly higher level than in controls (p less than 0.01). During day 3 when a high CHO diet was fed plasma NEFA levels fell in cirrhotics, and for most of the day the mean NEFA concentration in group B patients was significantly (p less than 0.05) lower than in normals. On day 3 glucose and fructose levels rose after each meal--much more in cirrhotics than in controls (and more in group B than in group A), and for most of the day they were significantly higher in group B patients as compared to the controls (glucose p less than 0.01, fructose p less than 0.001). Our results supported the hypothesis that plasma NEFA would be lower following high CHO meals in cirrhotics than in controls. This suggests that a high NEFA utilisation, which occurs in fasting cirrhotics, is not present throughout the day. Following a CHO meal, we suggest that tissues derive energy directly from the dietary sugars which are present in high concentration during the period of absorption and that this reduces the post prandial requirement for NEFA.

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.

Resistance to insulin suppression of plasma free fatty acids in liver cirrhosis

Insulin action on carbohydrate metabolism is known to be reduced in liver cirrhosis. However, little is known about the effect of insulin on free fatty acid (FFA) metabolism in these patients. To investigate this aspect we performed a two-step insulin euglycemic clamp in 11 cirrhotic patients and 6 controls. Insulin was infused at 0.25 mU/Kg min from 0 to 100 min and at 1 mU/Kg from 100 to 200 min. The FFA lowering capacity of insulin was studied during the first step; the glucose metabolizing capacity (M) was evaluated during the second step. In the cirrhotic patients, the M value was lower than in controls (3.91 +/- 0.48 vs 7.75 +/- 1.09 mg/kg/min, respectively). During the low insulin infusion, FFA and glycerol plasma levels were decreased in both groups. However, the ability of insulin to suppress plasma FFA and glycerol was lower in cirrhotics than in controls. In fact, at 100 min, FFA were 50% of basal values in cirrhotics and 20% in controls (p less than 0.01), while glycerol plasma levels decreased to 70% of basal values in patients and to 56% in controls. The slope of the linear regression obtained between Ln-FFA concentrations vs time was significantly less in cirrhotic patients than in controls (p less than 0.001). In addition, a positive correlation was found between the M value (r = 0.70; p less than 0.01) and the slope of the Ln-FFA in each patient. These findings suggest that in cirrhotic patients the effects of insulin on both FFA and glucose metabolism are reduced.

Basal energy production rate and substrate use in stable cirrhotic patients

The basal energy production rate was measured using indirect calorimetry in 25 stable cirrhotic patients and 10 controls of comparable age. The endogenous substrate oxidation was also calculated by measuring urinary nitrogen excretion. The energy production rate was similar in cirrhotic patients and controls. The origins of liver disease and the degree of liver damage did not seem to influence the energy production rate. On the other hand, in cirrhotic patients, as in controls, a significant correlation was present between the energy production rate and parameters of body size, such as body weight and fat-free mass. As a consequence, cirrhotic patients with poor nutritional status, with a reduced fat-free mass, showed a lower energy production rate. The measured energy production rate was compared with the resting energy expenditure estimated by formulas commonly used in healthy individuals. The good agreement found between the measured energy production rate and calculated energy expenditure suggests that these formulas may be applied to stable cirrhotic patients in clinical practice. In cirrhotic patients, the oxidation of endogenous fat is the main contributor to basal energy production rate. The fat oxidation rate does not appear to be influenced by the hormonal pattern found in the cirrhotic patients. However, a significant correlation was present between fat oxidation and plasma free fatty acid levels. This confirms that the prevalent fat use in cirrhotic patients is supported by the greater availability of fat-derived substrates.

Reversible hepatomegaly and diabetes mellitus in an adult with disseminated histiocytosis X

Histiocytosis X rarely disseminates in an adult. The authors describe an unusual patients who presented with multiple areas of cutaneous and bone involvement. During the course of his disease he developed massive hepatomegaly. Aggregates of vacuolated histiocytes were found on liver biopsy. He subsequently developed diabetes mellitus complicated by ketoacidosis. Both his hepatomegaly and diabetes resolved spontaneously. No pancreatic nor pituitary abnormalities were identified. The combination of histiocytosis X, hepatomegaly, and diabetes mellitus has not been previously reported. The medical literature is reviewed with an emphasis on disseminated histiocytosis X in adults and the mechanism of glucose intolerance in liver disease.

Insulin and glucagon degradation in liver are not affected by hepatic cirrhosis

Hyperinsulinemia and impaired glucose tolerance are associated with liver cirrhosis. To investigate whether insulin-degrading activity in liver tissue plays a role in hyperinsulinemia, we assayed this activity in biopsy tissue from healthy and cirrhotic subjects. There was no difference in insulin degradation between these two groups. Also glucagon-degrading activity in liver tissue, which is catalyzed by the same enzyme as insulin-degrading activity, did not differ between the two groups studied. Therefore, insulin-degrading activity does not appear to be involved in the hyperinsulinemia that occurs in liver cirrhosis. The study provides indirect evidence that hyperinsulinemia and impaired glucose metabolism in liver cirrhosis are due to different mechanisms (receptorial and post-receptorial defects, and altered feedback inhibition of insulin secretion).

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.

Plasma lipid and lipoprotein response to carbohydrate feeding in cirrhotic patients

Serum lipids and lipoproteins, and glucose and insulin, were measured after an overnight fast, and during 3 days of a eucaloric diet rich in carbohydrate, in 15 patients with cirrhosis and seven normal subjects. Following the high-carbohydrate diet triglyceride rose in all groups but the increase in cirrhotics was lower than in normals. In normals and in cirrhotics with good liver function most of the triglyceride increment was carried in VLDL; in cirrhotics with poor liver function only 31% of the increment was found in VLDL, and 56% in triglyceride-rich LDL. In an earlier study on fat feeding, our cirrhotic patients with poor liver function had an impaired chylomicron and VLDL response; they also carried most of the triglyceride increment in triglyceride-rich LDL. The markedly impaired response of triglyceride-rich lipoproteins to both carbohydrate and fat feeding suggests that sick cirrhotics may have a problem with storage of dietary energy and that this contributes to loss of their adipose tissue.

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.

Exogenous lipid clearance in compensated liver cirrhosis

The tolerance to exogenous fats has been evaluated in patients with liver cirrhosis. A three-stage lipid clearance test with continuous infusion (3 hr) of a triglyceride emulsion, Intralipid, was performed on 10 patients with well compensated liver cirrhosis and 10 normolipidemic volunteers. During the infusion, blood samples were collected for the measurement of particulate triglycerides (TG) by nephelometry; samples were also collected for total TG, free fatty acids (FFA) and free tryptophan (TRP) determinations. Plasma endogenous triglycerides were calculated as the total minus exogenous, particulate, TG. The fractional removal rate (K2) and the maximal clearing capacity (K1) for exogenous TG were lower in patients than in controls, though a significant difference (p less than 0.05) was found only for K1. Endogenous TG and FFA showed a comparable rise in patients and controls during Intralipid infusion. A significant increase in free TRP was noted in cirrhotics upon maximal infusion rate. It is concluded that: in patients with well compensated liver cirrhosis the maximal clearing capacity (K1) for exogenous TG is impaired. Nonetheless, moderate amounts of fat may be removed at a normal rate from the bloodstream; a normal synthesis rate of exogenous TG may be maintained even in a severely damaged liver; considering the possible role of free TRP in the pathogenesis of hepatic encephalopathy (HE), the use of large amounts of lipids should be discouraged in patients with decompensated liver cirrhosis, or even avoided in those with impending or overt HE.

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.

Glucose tolerance and the insulin response in recently drinking alcoholic patients: possible effects of withdrawal

To investigate possible effects of withdrawal on carbohydrate metabolism in chronic alcoholic patients, intravenous glucose tolerance tests were performed in three periods in 11 alcoholic patients: early abstinence (less than three days), early abstinence plus ethanol (1 g/kg/BW IV), and late abstinence (three weeks later). According to liver biopsy results and laboratory tests, patients were classified as a group with liver damage (four cases) and a group without it (seven cases). In the group without damage, glucose tolerance expressed as K% and compared to a control group, was significantly decreased in early and late abstinence but not after the infusion of ethanol. Cases with damage also had glucose intolerance at admission. Plasma insulin levels after the glucose load were significantly lower at ten and 30 minutes in the group without damage, in early or late abstinence. They were normal in the presence of ethanol. Patients with liver damage presented higher basal and postglucose plasma insulin concentrations. It was concluded that glucose intolerance in alcoholic patients is a common finding that occurs in the presence or absence of liver damage. In cases with liver damage it seems to be due to peripheral insulin resistance. In those without damage it is related to low peripherovenous insulin levels.

Circulating somatostatin concentrations in healthy and cirrhotic subjects

Plasma insulin, glucagon, somatostatin, and glucose concentrations were measured in the fasting state as well as after mixed meals (breakfast, lunch, and dinner) in 10 cirrhotic patients and 10 control subjects during a 24-hour period. Cirrhotic patients had fasting glucose values higher than controls (at -15 min: 5.2 +/- 0.2 mmol/L v 3.9 +/- 0.5 mmol/L, P less than 0.05; at 0 min: 5.5 +/- 0.3 mmol/L v 4.3 +/- 0.5 mmol/L, P less than 0.01). After meals blood glucose values remained higher in cirrhotics than in controls. Insulin levels did not differ between the groups in the fasting state, but cirrhotics showed a lower response to meals. Corresponding glucagon concentrations were greater in cirrhotics than in controls before and after meals throughout the 24-hour period (from -15 min to 24 hour: P less than 0.01). BAsal plasma somatostatin levels in the cirrhotic group were significantly higher than in control subjects (at -15 min and at 0 min: P less than 0.05) and further increased after meals. Plasma somatostatin was heterogeneous in normal and cirrhotic group, but the increase in its concentrations in patients with chronic liver disease was for the most part a consequence of elevations in the 1600 and 3500 molecular weight components. The half-life of exogenously infused somatostatin in cirrhotics was comparable to that of controls. These results indicate that in liver cirrhosis elevated levels of circulating somatostatin are associated with hyperglucagonemia and impaired insulin release. The high plasma somatostatin levels observed in cirrhotic patients are the result of hypersecretion of the D cell rather than impaired removal of the peptide.

Hyperaminoacidaemia reduces insulin-mediated glucose disposal in healthy man

To determine whether hyperaminoacidaemia may modify insulin-mediated glucose disposal, normal subjects were studied with the euglycaemic glucose-clamp technique, with or without an amino acid infusion, at a rate sufficient to duplicate the plasma concentration of most amino acids. Steady-state glucose infusion rates to maintain euglycaemia were 36% lower during hyperaminoacidaemia (7.3 +/- 1.0 versus 11.4 +/- 0.8 mg X kg-1 X min-1, p less than 0.01) at comparable insulin concentrations (92 +/- 6 versus 93 +/- 7 mU/l respectively). Thus, under conditions of hyperinsulinaemia, amino acids could compete with glucose as metabolic fuels.

Mechanism of insulin resistance in human liver cirrhosis. Evidence of a combined receptor and postreceptor defect

Insulin resistance in liver cirrhosis may depend on either reduced sensitivity (receptor defect) and/or reduced response to insulin (postreceptor defect). To clarify the mechanism of such resistance, a [3H]glucose infusion (0.2 microCi/min) was performed for 120 min before and during a euglycemic clamp at approximately 100, 1,000, and 10,000 microU/ml steady state plasma insulin concentration in 18 compensated cirrhotics with portal hypertension and impaired glucose tolerance, and 18 healthy volunteers with no family history of diabetes, matched for sex, age, and weight. Mean fasting plasma insulin (29.2 +/- 3.4 SEM vs. 14.8 +/- 1.1 microU/ml) was significantly higher (P less than 0.001) in cirrhotics, while fasting plasma glucose was much the same in the two groups. Glucose use (milligrams per kilogram per minute) was significantly lower in cirrhotics at all three steady state plasma insulin levels: 3.04 +/- 0.34 vs. 7.72 +/- 0.61 (P less than 0.001) at approximately 100; 6.05 +/- 1.07 vs. 11.45 +/- 1.24 (P less than 0.001) at approximately 1,000; and 11.69 +/- 0.69 vs. 14.13 +/- 0.74 (P less than 0.05) at approximately 10,000 microU/ml. Mean plasma C-peptide was significantly higher in cirrhotics both basally and during the steady states (P less than 0.001); it was completely suppressed at approximately 10,000 microU/ml in controls and only 57.5% of the baseline in cirrhotics. Endogenous glucose production (milligrams per kilogram per minute) was much the same in the two groups in the fasting state and almost entirely suppressed in the controls (0.10 +/- 0.05 vs. 0.48 +/- 0.11, P less than 0.001) at approximately 100 microU/ml; at approximately 1,000 microU/ml a residual glucose production, 0.07 +/- 0.05, was observed in the cirrhotics only. In addition, insulin binding and 3-ortho-methyl-glucose transport were studied in vitro in six cirrhotics and six controls. Insulin binding to circulating monocytes and isolated adipocytes was significantly lower (P less than 0.025) in cirrhotics in all insulin concentration studies. Glucose transport values on isolated adipocytes were significantly lower in cirrhotics both basally (P less than 0.001) and at maximal insulin concentration (P less than 0.05). These results suggest that insulin resistance in human cirrhosis is more dependent on depressed peripheral glucose use than on increased endogenous glucose production, and that a combined receptor and postreceptor defect in insulin action on target cells seems to be present.

Insulin action in cirrhosis

In vivo insulin sensitivity and adipocyte insulin binding and action were assessed in 16 patients with histologically proven hepatic cirrhosis and 11 age-, weight- and sex-matched normal control subjects. The cirrhotic group displayed impaired oral glucose tolerance, despite an exaggerated serum immunoreactive insulin response, and in vivo insulin resistance as assessed both by the euglycemic hyperinsulinemic clamp and the glucose-insulin infusion techniques. Adipocytes of the cirrhotic patients bound significantly less insulin than those of the control subjects (2.21 +/- 0.12% vs. 2.64 +/- 0.13%; p less than 0.05). Although the adipocytes from the cirrhotic patients were less sensitive to insulin stimulation in vitro (half-maximal stimulation at 60.0 +/- 8.0 vs. 21.8 +/- 3.3 pM; p less than 0.001), they exhibited higher maximum rates of lipogenesis. Comparison of the responses of the alcoholic, primary biliary cirrhosis and cryptogenic subgroups suggested pronounced differences in the maximum rates of lipogenesis. There were significant negative correlations between specific binding to adipocytes and both fasting serum immunoreactive insulin and in vivo insulin resistance as assessed by glucose-insulin infusion. Monocyte insulin binding was normal in the cirrhotic group and did not correlate with in vivo insulin resistance. It is concluded that both binding and postbinding defects in insulin target organ cells contribute to the marked in vivo insulin resistance of hepatic cirrhosis.

Correction of altered plasma amino acid pattern in cirrhosis of the liver by somatostatin

The purpose of our study was to evaluate the effect of somatostatin (500 microgram/h intravenously) upon insulin, c-peptide, glucagon and plasma amino acids concentrations in patients with and without cirrhosis of the liver. The typical plasma amino acid pattern in cirrhosis is characterised by increased concentrations of the aromatic amino acids and decreased concentrations of the branched chain amino acids and of alanine and glycine. After administration of somatostatin insulin, c-peptide and glucagon concentrations decreased and those of the branched chain amino acids in both groups increased; in addition in patients with cirrhosis the plasma concentrations of threonine, serine, glycine, alanine, lysine, and arginine increased also. Infusion of somatostatin plus insulin in patients with cirrhosis succeeded in preventing the increase in the branched chain amino acid concentrations, while the infusion of somatostatin plus glucagon decreased threonine, serine, glycine, alinine, phenylalanine, tyrosine, lysine and arginine concentrations. It is therefore suggested that the effect of somatostatin on the plasma amino acids may be because of the reduction of insulin and glucagon concentrations; however, other effects of somatostatin cannot be excluded at present.

Total and individual free fatty acid concentrations in liver cirrhosis

The finding of high plasma free fatty acid (FFA) levels in cirrhotic patients has been attributed either to decreased hepatic clearance or to enhanced fat mobilization. To better clarify these hypotheses, total and individual FFA and glycerol levels were determined in 21 cirrhotic patients with different degrees of hepatocellular damage (evaluated by liver function tests), portal hypertension (evaluated by endoscopy and clinical signs), and nutritional status (evaluated by anthropometric and biohumoral parameters) and in 10 age- and sex-matched healthy subjects. Glucose tolerance and insulin and glucagon levels were determined in all individuals. Well-nourished and malnourished patients were identified within the cirrhotic group. Plasma FFA and glycerol concentrations were well correlated (r = 0.47, P less than 0.05), levels being significantly higher in cirrhotic individuals than in controls (746.6 +/- 46.29 SE v 359.22 +/- 40.82 mumol/L, P less than 0.001 for plasma FFA; 150.1 +/- 3.12 v 82.5 +/- 9.2 mumol/L, P less than 0.01 for glycerol). Plasma FFA and glycerol showed no correlation with the liver function test results or portal hypertension parameters. Interestingly, plasma levels of FFA and glycerol were influenced by the nutritional status, significantly higher FFA levels being observed in the well-nourished than in the malnourished patients (842.5 +/- 47.5 v 563.4 +/- 78 mumol/L, P less than 0.005). Furthermore, a positive correlation was found between plasma glycerol level and percentage of triceps skinfold (r = 0.45, P less than 0.05). No correlation was found between plasma levels of FFA or glycerol and glucose tolerance, insulin and glucagon.(ABSTRACT TRUNCATED AT 250 WORDS)