Relationship between insulin sensitivity, insulin secretion and glucose tolerance in cirrhosis

Autoimmune liver diseases and diabetes: A propensity score matched analysis and a proportional meta-analysis

BACKGROUND AND AIMS

Patients with some chronic liver diseases have increased risk of diabetes. Whether this is also the case for patients with autoimmune liver diseases is unknown. The study aimed to calculate risk and worldwide prevalence of diabetes in patients with autoimmune hepatitis (AIH), primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC).

METHODS

We performed a case-control study using data from the United Kingdom Biobank (UKB) and compared frequency of type 1 diabetes (T1D) and type 2 diabetes (T2D) in AIH and PBC with age-, sex-, BMI- and ethnicity-matched controls. Next, we performed a systematic review and proportional meta-analysis searching PubMed, Embase, Cochrane Library and Web of Science (inception to 1 May 2022 [AIH]; 20 August 2022 [PBC]; 11 November 2022 [PSC]). The pooled prevalence of diabetes was calculated using an inverse method random effects model.

RESULTS

Three hundred twenty-eight AIH patients and 345 PBC patients were identified in UKB and risk of T1D and T2D significantly increased compared with matched controls. Our systematic search identified 6914 records including the UKB study. Of these, 77 studies were eligible for inclusion comprising 36 467, 39 924 and 4877 individuals with AIH, PBC and PSC, respectively. The pooled prevalence of T1D was 3.8% (2.6%-5.7%), 1.7% (0.9%-3.1%), 3.1% (1.9%-4.8%) and of T2D 14.8% (11.1%-19.5%), 18.1% (14.6%-22.2%), 6.3% (2.8%-13.3%) in patients with AIH, PBC and PSC, respectively.

CONCLUSIONS

Patients with autoimmune liver diseases have increased risk of diabetes. Increased awareness of diabetes risk in patients with autoimmune liver diseases is warranted.

A glycogen storage disease type 1a patient with type 2 diabetes

Background

Glycogen storage disease type 1a (GSD1a) is an inborn genetic disease caused by glucose-6-phosphatase-α (G6Pase-α) deficiency and is often observed to lead to endogenous glucose production disorders manifesting as hypoglycemia, hyperuricemia, hyperlipidemia, lactic acidemia, hepatomegaly, and nephromegaly. The development of GSD1a with diabetes is relatively rare, and the underlying pathogenesis remains unclear.

Case presentation

Here we describe a case of a 25-year-old Chinese female patient with GSD1a, who developed uncontrolled type 2 diabetes mellitus (T2DM) as a young adult. The patient was diagnosed with GSD1a disease at the age of 10 and was subsequently treated with an uncooked cornstarch diet. Recently, the patient was treated in our hospital for vomiting and electrolyte imbalance and was subsequently diagnosed with T2DM. Owing to the impaired secretory function of the patient’s pancreatic islets, liver dysfunction, hypothyroidism, severe hyperlipidemia, and huge hepatic adenoma, we adopted diet control, insulin therapy, and hepatic adenoma resection to alleviate this situation. The WES discovered compound heterozygous mutations at the exon 5 of G6PC gene at 17th chromosome in the patient, c.648G>T (p.L216 L, NM_000151.4, rs80356484) in her father and c.674T>C (p.L225 P, NM_000151.4, rs1555560128) in her mother. c.648G>T is a well-known splice-site mutation, which causes CTG changing to CTT at protein 216 and creates a new splicing site 91 bp downstream of the authentic splice site, though both codons encode leucine. c.674T>C is a known missense mutation that causes TGC to become CGC at protein 225, thereby changing from coding for leucine to coding for proline.

Conclusion

We report a rare case of GSD1a with T2DM. On the basis of the pathogenesis of GSD1a, we recommend attentiveness to possible development of fasting hypoglycemia caused by GSD and postprandial hyperglycemia from diabetes. As the disease is better identified and treated, and as patients with GSD live longer, this challenge may appear more frequently. Therefore, it is necessary to have a deeper and more comprehensive understanding of the pathophysiology of the disease and explore suitable treatment options.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01344-3.

Hepatogenous Diabetes - A Report from Central India

Background/Objectives

Cirrhosis of liver is associated with loss of liver function, portal hypertension, and pancreatic β-cell dysfunction leading to hepatogenous diabetes (HD). Often HD is an underestimated and understudied problem, particularly in the Indian subcontinent, where the prevalence of both Chronic liver disease (CLD) and diabetes is high. Hence this study was planned to highlight the prevalence of HD and its association with the severity of cirrhosis.

Methods

A total of 121 cirrhotic patients without a history of diabetes were included in this prospective cross-sectional study. Seventy five g oral glucose tolerance test (OGTT) was done in all patients. Fasting serum insulin levels were done to calculate insulin resistance (IR) using homeostatic model assessment-insulin resistance (HOMA-IR). Upper gastrointestinal endoscopy was done to detect varices. Patients were divided into HD group and non-HD group for comparison of results.

Results

HD was seen in 52 (42.98%) patients; among them, 63.4% did not show evidence of HD by fasting plasma glucose (FPG) levels. Impaired glucose tolerance (IGT) was seen in 58 (47.93%) patients. Compared with the non-HD group, the HD group had significantly higher model for end-stage liver disease (MELD) score (P = 0.038), HOMA-IR (P < 0.001), incidence of large varices (P < 0.001) and variceal bleeding (P < 0.001). A statistically significant association was noted between HD and Hepatocellular carcinoma (HCC) (P < 0.001).

Conclusion

Patients with cirrhosis had a high prevalence of IGT, IR, and HD. The presence of HD is well associated with the severity of cirrhosis in the form of higher MELD score (>15), CTP score (>10), higher bilirubin levels, large varices, bleeding varices, and HCC. FPG levels and glycated hemoglobin (HbA1c) cannot be relied upon, and OGTT aids in the unmasking of HD in these patients.

Intrahepatic fat, irrespective of ethnicity, is associated with reduced endogenous insulin clearance and hepatic insulin resistance in obese youths: A cross-sectional and longitudinal study from the Yale Pediatric NAFLD cohort

AIM

To evaluate whether intrahepatic fat accumulation contributes to impaired insulin clearance and hepatic insulin resistance across different ethnic groups.

METHODS

The intrahepatic fat content (HFF%) was quantified by magnetic resonance imaging in a multi-ethnic cohort of 632 obese youths aged 7-18 years at baseline and after a 2-year follow-up. Insulin secretion rate (ISR), endogenous insulin clearance (EIC) and hepatic insulin resistance index (HIRI) were estimated by modelling glucose, insulin and C-peptide data during 3-hour, 9-point oral glucose tolerance tests.

RESULTS

African American youths exhibited the lowest HFF% and a prevalence of non-alcoholic fatty liver disease (NAFLD) less than half of that shown by Caucasians and Hispanics. Furthermore, African Americans had lower EIC and glucose-stimulated ISR, despite similar HIRI and plasma insulin levels, compared with Caucasians and Hispanics. EIC and HIRI were markedly reduced in individuals with NAFLD and declined across group-specific HFF% tertiles in all ethnic groups. Consistently, the HFF% correlated with EIC and HIRI, irrespective of the ethnic background, after adjustment for age, sex, ethnicity, adiposity, waist-hip ratio, pubertal status and plasma glucose levels. An increased HFF% at follow-up was associated with decreased EIC and increased HIRI across all groups.

CONCLUSIONS

Intrahepatic lipid accumulation is associated with reduced insulin clearance and hepatic insulin sensitivity in obese youths, irrespective of their ethnic background.

Post-transplant diabetes mellitus and preexisting liver disease - a bidirectional relationship affecting treatment and management

Liver cirrhosis and diabetes mellitus (DM) are both common conditions with significant socioeconomic burden and impact on morbidity and mortality. A bidirectional relationship exists between DM and liver cirrhosis regarding both etiology and disease-related complications. Type 2 DM (T2DM) is a well-recognized risk factor for chronic liver disease and vice-versa, DM may develop as a complication of cirrhosis, irrespective of its etiology. Liver transplantation (LT) represents an important treatment option for patients with end-stage liver disease due to non-alcoholic fatty liver disease (NAFLD), which represents a hepatic manifestation of metabolic syndrome and a common complication of T2DM. The metabolic risk factors including immunosuppressive drugs, can contribute to persistent or de novo development of DM and NAFLD after LT. T2DM, obesity, cardiovascular morbidities and renal impairment, frequently associated with metabolic syndrome and NAFLD, may have negative impact on short and long-term outcomes following LT. The treatment of DM in the context of chronic liver disease and post-transplant is challenging, but new emerging therapies such as glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium–glucose cotransporter 2 inhibitors (SGLT2i) targeting multiple mechanisms in the shared pathophysiology of disorders such as oxidative stress and chronic inflammation are a promising tool in future patient management.

Hepatic effects of low-dose rate radiation in natural mouse populations (Apodemus uralensis and Apodemus agrarius): comparative interspecific analysis

Hypothesis: Natural mouse populations in radioactive contamination zone provide adequate information about dose loads and biological effects for 'non-human biota'. The comparative analysis of the responses of different species of mice allows us to reveal the possible variation in the effects of low-dose rate radiation relative to the ecological-physiological and functional-metabolic features of the species.Materials and methods: Objects of study - two sympatric rodent species [pygmy wood mouse (Apodemus uralensis Pallas, 1811) and striped field mouse (Apodemus agrarius Pallas, 1771)] caught on the territory of the East-Ural radioactive trace (EURT). The EURT zone is consequence the Kyshtym accident in South Urals in 1957. Nowadays, the main dose-forming radionuclide is β-emitting ⁹⁰Sr. The individual dose rate of impacted mice caused by internal exposure to ⁹⁰Sr varied from 0.021 to 0.152 mGy/day. The baseline functional-metabolic characteristics of the liver were researched: protein-, lipid-, and glycogen-synthesizing processes; glycolysis; aerobic synthesis of ATP; lipid peroxidation; and the H₂O₂-scavenging enzymatic status; and the functional activity of the genome.Results: The hepatic shifts for impacted populations are amplified with increasing dose rate of irradiation, regardless of which species is considered. But, the response of closely related species of rodents to irradiation is different both in the vector and the level (in A. agrarius sample was 2 time higher than that for A. uralensis).Conclusion: The radiation-induced hepatic shifts in A. uralensis from the EURT area correspond to the chronic response under stressful environmental conditions. The impacted population of A. agrarius can be considered the more reactive species to the radiation burden, demonstrating an acute effect. The interspecies contrast in the radiation response is associated with the original interspecies differences (background rodents' samples in 28 km from the impact study site), and also the degree of residency of the species in the impact plots.

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.

Significant effects of late evening snack on liver functions in patients with liver cirrhosis: A meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Reducing post-absorptive (fasting) phase by eating late evening snacks (LESs) is a potential intervention to improve substrate utilization and reverse sarcopenia. This study analyzed the results of published randomized controlled trials and controlled clinical trials to evaluate the effects of LES on liver function of patients with cirrhosis.

METHODS

A meta-analysis was conducted. The search strategy included electronic database searches, and 300 articles were searched. Eight of these articles provided qualified data for pooling and analysis. Outcomes assessments included serum albumin, total bilirubin, alanine aminotransferase, prothrombin time, and aspartate aminotransferase, complications of cirrhosis, severity of liver disease, and blood glucose levels.

RESULTS

Our analysis included eight studies comprising 341 patients (167 in LES groups and 174 in control groups). The results showed that LES intervention helped to maintain liver reserves. These eight studies demonstrated that LES intervention had significant effects for liver biochemical parameters on albumin, ammonia, and prothrombin time, with respective effect sizes of 0.233, -0.425, and -0.589; liver enzymes include aspartate aminotransferase and alanine aminotransferase, with respective effect sizes of -0.320 and -0.284. Studies on clinical signs of liver dysfunction showed lower occurrence rates of ascites and hepatic encephalopathy than in the control group. LES had no significant effect on Child-Pugh score.

CONCLUSIONS

The overall results of the meta-analysis indicated that having LES can improve liver function reserve for patients with liver cirrhosis, with or without hepatocellular carcinoma. LES is a promising intervention for reversing anabolic resistance and the sarcopenia of cirrhosis, resulting in an improved quality of life for patients with cirrhosis.

Structural-functional modifications of the liver to chronic radioactive exposure in pygmy wood mouse (Apodemus uralensis) within the East-Urals Radioactive Trace

The hepatic parameters (contents of glycogen, total lipids, nuclear and cytoplasmic proteins, DNA and RNA, fructose-6-phosphate, water, lipid peroxidation products, as well as activities of succinate dehydrogenase and glucose phosphate isomerase), radiometric data, and the relative population abundance of the pygmy wood mouse (Apodemus uralensis Pall., 1811) inhabiting natural (Middle Urals, Southern Urals, and Trans-Urals) areas and radioactivity territory (the EURT zone after of the Kyshtym accident in the South Urals in 1957) were analysed. Structural-functional modifications of the liver in A. uralensis from the EURT area are presented, taking into account irradiation power by dose-forming radionuclides (external and internal exposure to ¹³⁷Cs and ⁹⁰Sr), population size, and reproductive status (sexually immature and sexually mature yearlings, representing different ontogenetic patterns). The sexually immature mice from the EURT area can be considered to be the more sensitive (reactive) intrapopulation group to synergistic factors, such as radiation burden and population overabundance. The extent of structural-functional hepatic modification under current conditions of radionuclide exposure, in addition to the 60 year long effect of radioactive contamination in the EURT, can exceed the level of natural (geographic) variation observed in this species in the Urals region, which points to a long term evolutionary-ecological process.

Sleep disturbances in patients with liver cirrhosis: prevalence, impact, and management challenges

Sleep-wake disturbances are common in liver cirrhosis and associated with impaired quality of life. The most common abnormalities are insomnia (difficulties falling asleep and maintaining sleep, or unrefreshing sleep), excessive daytime sleepiness, and sleep-wake inversion (disturbances of circadian rhythmicity). The underlying pathophysiological mechanisms for sleep disturbances in cirrhosis are complex and may include disturbed metabolism of melatonin and glucose, alterations in thermoregulation, and altered ghrelin secretion profiles. Sleep-wake abnormalities are related to the presence of hepatic encephalopathy (HE) and improvement in sleep parameters can be observed when HE is properly managed. A few non-specific treatments for sleep-wake abnormalities have been tried with encouraging results for hydroxyzine and modafinil. However, due to the potential for medication toxicity in these disabled patients, further studies are needed to address the potential role of non-drug therapies in this population (eg, cognitive behavioral therapy, mindfulness, yoga) that have demonstrated usefulness in insomnia disorders.

Hepatic Insulin Clearance in Regulation of Systemic Insulin Concentrations-Role of Carbohydrate and Energy Availability

Hyperinsulinemia is the hallmark of insulin resistance in obesity, and the relative importance of insulin clearance, insulin resistance, and insulin hypersecretion has been widely debated. On the basis of recent experimental evidence, we summarize existing evidence to suggest hepatic insulin clearance as a major and immediate regulator of systemic insulin concentrations responding within days to altered dietary energy and, in particular, carbohydrate intake. Hepatic insulin clearance seems to be closely associated with opposite alterations in hepatic lipid content and glucose production, providing a potential mechanistic link to hepatic insulin sensitivity. The molecular regulation of insulin clearance in the liver is likely to involve changes in insulin binding and receptor internalization in response to the dietary alterations, the molecular mechanisms of which await further research.

Outcomes in patients with diabetes 10 years after liver transplantation

BACKGROUND

There are discrepancies between studies regarding the effect of diabetes mellitus on morbidity and mortality in patients undergoing liver transplantation. The aim of the present study was to compare mortality, risk of liver graft rejection, and cardiovascular events in patients with and without diabetes undergoing liver transplantation over a 10-year follow-up period.

METHODS

A retrospective study was performed on 183 patients who underwent liver transplantation in 2005 and 2006. Mortality and morbidity data were collected until 2016, including information on mortality and survival time, graft rejection and graft survival time, coronary heart disease, stroke, and peripheral arterial ischemia.

RESULTS

During the follow-up, 41.3% and 27.8% of patients in the groups with and without diabetes, respectively, died. A trend for lower survival time was observed in patients with diabetes, although this effect was not confirmed by the Cox regression model. There was an increased risk of graft rejection in the group with diabetes compared with the group without diabetes ( P  < 0.001). In the survival analysis, diabetes was associated with reduced graft survival time ( P  = 0.001). Cardiovascular events were also more likely in the group with diabetes ( P  = 0.005).

CONCLUSIONS

In the present study diabetes was associated with a higher risk of liver graft rejection and cardiovascular events. There was also a trend for higher mortality, although the effect was not statistically significant. These findings suggest that patients with diabetes require a more rigorous pretransplant evaluation and closer monitoring after transplantation in order to try to reduce associated complications.

Hepatogenous diabetes: Is it time to separate it from type 2 diabetes?

By definition, hepatogenous diabetes is directly caused by loss of liver function, implying that it develops after cirrhosis onset. Therefore, it should be distinguished from type 2 diabetes developing before cirrhosis onset, in which specific causes of liver disease play a major role, in addition to traditional risk factors. Currently, although hepatogenous diabetes shows distinct pathophysiological and clinical features, it is not considered as an autonomous entity. Recent evidence suggests that the failing liver exerts an independent "toxic" effect on pancreatic islets resulting in β-cell dysfunction. Moreover, patients with hepatogenous diabetes usually present with normal fasting glucose and haemoglobin A_1c levels and abnormal response to an oral glucose tolerance test, which is therefore required for diagnosis. This article discusses the need to separate hepatogenous diabetes from type 2 diabetes occurring in subjects with chronic liver disease and to identify individuals suffering from this condition for prognostic and therapeutic purposes.

Diagnosis and Clinical Implications of Diabetes in Liver Cirrhosis: A Focus on the Oral Glucose Tolerance Test

The liver and skeletal muscles are responsible for maintaining glucose metabolism. As chronic liver disease progresses to cirrhosis, the loss of liver function is exacerbated and leads to the deterioration of skeletal muscle. Consequently, impaired glucose tolerance (IGT) and insulin resistance are often observed in patients with liver cirrhosis. Early stage cirrhosis with hepatogenous diabetes is characterized by marked postprandial hyperglycemia and hyperinsulinemia. Generally, it is possible to underestimate IGT when using either the conventional fasting plasma glucose (FPG) criterion or hemoglobin A_1c (HbA_1c) levels despite their status as the gold standard for diagnosing diabetes. The number of cirrhotic patients with diabetes tends to be underestimated because many of these patients show lower FPG levels or HbA_1c, which masks their IGT. In such cases, the oral glucose tolerance test is recommended to evaluate patients with suspected postprandial hyperglycemia who present with a normal FPG. Moreover, in addition to the Child-Pugh score, the early detection of diabetes may be a useful prognostic marker for patients with liver cirrhosis.

Re-evaluation of glycated hemoglobin and glycated albumin with continuous glucose monitoring system as markers of glycemia in patients with liver cirrhosis

Liver cirrhosis (LC) is frequently accompanied by glucose intolerance. The present study was designed to determine whether glycated hemoglobin A1c (HbA1c) and glycated albumin (GA) were predictive markers of glycemia, as determined by a continuous glucose monitoring system (CGMS), in patients with LC. A total of 30 patients with LC, including 3, 19, 5, 2 and 1 with LC due to hepatitis B virus, hepatitis C virus, non-alcoholic steatohepatitis, alcohol and unknown causes, respectively, were assessed by CGMS. The average, maximum and minimum blood glucose (BG) levels were measured by CGMS, and correlated with HbA1c and GA. The average, maximum and minimum BG in these individuals were 142±38.7, 209.3±65.7 and 85.1±25.4 mg/dl, respectively. HbA1c was significantly correlated with average BG (r=0.447, P=0.015) and maximum BG (r=0.523, P=0.004). In addition, GA was significantly correlated with average BG (r=0.687, P<0.001) and maximum BG (r=0.648, P<0.001). Neither HbA1c nor GA was significantly correlated with minimum BG. Correlation analysis yielded formulas by which HbA1c and GA were predictive of average BG in individuals with LC: Average BG=19.2 × HbA1c (%) + 36.5 and average BG=6.6 × GA (%) + 13.0, respectively. In conclusion, HbA1c and GA showed significant correlations with average and maximum BG, as determined by CGMS. The derived formulas allow for estimates of average BG based on HbA1c and GA, and may contribute to the control of glycemia in patients with LC.

Glucose fluctuations reduce quality of sleep and of life in patients with liver cirrhosis

BACKGROUND

Sleep disturbance and decreased health-related quality of life (HRQOL) are significant complaints in patients with liver cirrhosis. Although the etiology of these complications is unclear, we propose that glucose intolerance may be a predisposing factor. Therefore, our aim was to investigate the relationship between glucose intolerance and these complications.

METHODS

We assessed continuous glucose monitoring in 43 patients with chronic liver disease. Among these patients, 36 completed the Pittsburgh Sleep Quality Index (PSQI), the 36-Item Short-form Health Survey (SF-36), and the Neuropsychological Test (NPT). We also assessed the change in glucose fluctuations between preoperative periods and 1 year after liver transplantation in 13 patients.

RESULTS

Standard deviation (SD) of blood glucose was 24.15 ± 13.52. SD values correlated to glucose metabolism measures, including HbA1c and glycoalbumin. SD values also correlated to markers of liver fibrosis, including type IV collagen. Twenty-one patients (58.3 %) were classified as "poor" sleepers, with a global PSQI score ≥6. Glucose fluctuations correlated with the global PSQI score (r = 0.456, p = 0.008) and the SF-36 score (r = 0.434, p = 0.013). Multivariate regression analysis identified SD values as an independent risk factor for sleep disturbance (r = 0.12, p = 0.039) and decreased HRQOL (r = -0.32, p = 0.024). SD values did not correlate with the NPT. SD values were also improved in 11 (84.6 %) patients 1 year after liver transplantation.

CONCLUSION

Abnormal glucose fluctuations are a risk factor for sleep disturbance and decrease of HRQOL in patients with cirrhosis.

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.

Influence of gastrointestinal factors on glucose metabolism in patients with cirrhosis

BACKGROUND AND AIM

The impaired glucose tolerance in cirrhosis is poorly understood. We evaluated the influence of gastrointestinal-mediated glucose disposal and incretin effect in patients with cirrhosis.

METHODS

Non-diabetic patients with Child-Pugh A or B cirrhosis (n = 10) and matched healthy controls (n = 10) underwent a 50-g oral glucose tolerance test (OGTT) and an isoglycemic intravenous glucose infusion. We presented data as median ± interquartile range and compared groups using non-parametric analysis of variance.

RESULTS

Patients with cirrhosis were glucose intolerant compared with healthy controls (4-h OGTTAUC : 609 ± 458 vs 180 ± 155 min × mmol/L; P = 0.005), insulin resistant (homeostatic model assessment for insulin resistance: 3.7 ± 4.9 vs 2.6 ± 1.4; P = 0.014) and had fasting hyperglucagonemia (8 ± 3 vs 3 ± 4 pmol/L; P = 0.027). Isoglycemia was achieved using 35 ± 12 g of intravenous glucose in patients with cirrhosis compared with 24 ± 10 g in healthy controls (P = 0.003). The gastrointestinal-mediated glucose disposal was markedly lower in patients with cirrhosis (30 ± 23 vs 52 ± 20%; P = 0.003). Despite higher levels of the incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic peptide patients with cirrhosis had reduced incretin effect (35 ± 44 vs 55 ± 30%; P = 0.008).

CONCLUSION

Impaired gastrointestinal-mediated glucose disposal and reduced incretin effect may contribute to the glucose intolerance seen in patients with cirrhosis.

Diabetes diminishes the portal-systemic collateral vascular response to vasopressin via vasopressin receptor and Gα proteins regulations in cirrhotic rats

Liver cirrhosis may lead to portal-systemic collateral formation and bleeding. The hemostatic effect is influenced by the response of collateral vessels to vasoconstrictors. Diabetes and glucose also influence vasoresponsiveness, but their net effect on collaterals remains unexplored. This study investigated the impact of diabetes or glucose application on portal-systemic collateral vasoresponsiveness to arginine vasopressin (AVP) in cirrhosis. Spraque-Dawley rats with bile duct ligation (BDL)-induced cirrhosis received vehicle (citrate buffer) or streptozotocin (diabetic, BDL/STZ). The in situ collateral perfusion was done after hemodynamic measurements: Both were perfused with Krebs solution, D-glucose, or D-glucose and NaF, with additional OPC-31260 for the BDL/STZ group. Splenorenal shunt vasopressin receptors and Gα proteins mRNA expressions were evaluated. The survival rate of cirrhotic rats was decreased by STZ injection. The collateral perfusion pressure changes to AVP were lower in STZ-injected groups, which were reversed by OPC-31260 (a V2R antagonist) and overcome by NaF (a G protein activator). The splenorenal shunt V2R mRNA expression was increased while Gα proteins mRNA expressions were decreased in BDL/STZ rats compared to BDL rats. The Gαq and Gα11 mRNA expressions also correlated with the maximal perfusion pressure changes to AVP. Diabetes diminished the portal-systemic collateral vascular response to AVP in rats with BDL-induced cirrhosis, probably via V2 receptor up-regulation and Gα proteins down-regulation.

Perioperative monitoring in liver transplant patients

Liver transplant (LT) is a major surgical undertaking involving major fluid shifts, hemodynamic instability and metabolic derangements in a patient with preexisting liver failure and multisystemic derangements. Monitoring and organ support initiated in the preoperative phase is continued intraoperatively and into the postoperative phase to ensure an optimal outcome. As cardiovascular events are the leading cause of non-graft related death among LT recipients, major emphasis is placed on cardiovascular monitoring. The other essential monitoring are the continuous assessment of coagulapathy, extent of metabolic derangements, dyselectrolytemis and intracranial pressure monitoring in patients with fulminant hepatic failure. The type and extent of monitoring differs with need according to preexisting child status of the patient and the extent of systemic derangements. It also varies among transplant centers and is mainly determined by individual or institutional practices.

Insulin resistance, ceramide accumulation, and endoplasmic reticulum stress in human chronic alcohol-related liver disease

Background. Chronic alcohol-related liver disease (ALD) is mediated by insulin resistance, mitochondrial dysfunction, inflammation, oxidative stress, and DNA damage. Recent studies suggest that dysregulated lipid metabolism with accumulation of ceramides, together with ER stress potentiate hepatic insulin resistance and may cause steatohepatitis to progress. Objective. We examined the degree to which hepatic insulin resistance in advanced human ALD is correlated with ER stress, dysregulated lipid metabolism, and ceramide accumulation. Methods. We assessed the integrity of insulin signaling through the Akt pathway and measured proceramide and ER stress gene expression, ER stress signaling proteins, and ceramide profiles in liver tissue. Results. Chronic ALD was associated with increased expression of insulin, IGF-1, and IGF-2 receptors, impaired signaling through IGF-1R and IRS1, increased expression of multiple proceramide and ER stress genes and proteins, and higher levels of the C14, C16, C18, and C20 ceramide species relative to control. Conclusions. In human chronic ALD, persistent hepatic insulin resistance is associated with dysregulated lipid metabolism, ceramide accumulation, and striking upregulation of multiple ER stress signaling molecules. Given the role of ceramides as mediators of ER stress and insulin resistance, treatment with ceramide enzyme inhibitors may help reverse or halt progression of chronic ALD.

Late evening snack: exploiting a period of anabolic opportunity in cirrhosis

BACKGROUND AND AIM

Cirrhosis is a state of accelerated starvation with impaired protein synthesis. Increased rate of gluconeogenesis and alterations in skeletal muscle signaling pathways result in anabolic resistance and consequent loss of muscle mass or sarcopenia in cirrhosis. Late evening snack (LES) is an intervention to reduce the postabsorptive (fasting) phase with the potential to improve substrate utilization and reverse sarcopenia. Published reports were evaluated to examine the effect of LES on regulation of substrate utilization (short-term studies) and nutritional outcomes (long-term studies).

METHODS

PubMed, EMBASE, Google scholar and OVID databases were searched. All studies published on LES in cirrhosis were included. Studies that included few (n < 3) subjects and patients with hepatocellular carcinoma were excluded.

RESULTS

Late evening snack decreased lipid oxidation and improved nitrogen balance, irrespective of the composition or type of formulation used. Daytime isocaloric isonitrogenous snacks did not have the metabolic or clinical benefit of LES. LES decreased skeletal muscle proteolysis. No studies have examined its effect on muscle protein synthesis. There was inconsistent translation into an increase in lean body or skeletal muscle mass. Improved quality of life occurs but decreased mortality or need for transplantation has not been reported. The optimal composition of LES has not been defined, but based on mechanistic considerations, a branched chain supplemented LES holds most promise.

CONCLUSIONS

Late evening snack holds the most promise as an intervention to reverse anabolic resistance and sarcopenia of cirrhosis with improved quality of life in patients with cirrhosis. Long term benefit and improved survival need critical evaluation.

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.

Hepatitis B virus X protein regulates hepatic glucose homeostasis via activation of inducible nitric oxide synthase

Dysregulation of liver functions leads to insulin resistance causing type 2 diabetes mellitus and is often found in chronic liver diseases. However, the mechanisms of hepatic dysfunction leading to hepatic metabolic disorder are still poorly understood in chronic liver diseases. The current work investigated the role of hepatitis B virus X protein (HBx) in regulating glucose metabolism. We studied HBx-overexpressing (HBxTg) mice and HBxTg mice lacking inducible nitric oxide synthase (iNOS). Here we show that gene expressions of the key gluconeogenic enzymes were significantly increased in HepG2 cells expressing HBx (HepG2-HBx) and in non-tumor liver tissues of hepatitis B virus patients with high levels of HBx expression. In the liver of HBxTg mice, the expressions of gluconeogenic genes were also elevated, leading to hyperglycemia by increasing hepatic glucose production. However, this effect was insufficient to cause systemic insulin resistance. Importantly, the actions of HBx on hepatic glucose metabolism are thought to be mediated via iNOS signaling, as evidenced by the fact that deficiency of iNOS restored HBx-induced hyperglycemia by suppressing the gene expression of gluconeogenic enzymes. Treatment of HepG2-HBx cells with nitric oxide (NO) caused a significant increase in the expression of gluconeogenic genes, but JNK1 inhibition was completely normalized. Furthermore, hyperactivation of JNK1 in the liver of HBxTg mice was also suppressed in the absence of iNOS, indicating the critical role for JNK in the mutual regulation of HBx- and iNOS-mediated glucose metabolism. These findings establish a novel mechanism of HBx-driven hepatic metabolic disorder that is modulated by iNOS-mediated activation of JNK.

Nonalcoholic fatty liver is a risk factor for postprandial hyperglycemia, but not for impaired fasting glucose

PURPOSE

The first aim of this study was to elucidate the relationship between impaired glucose tolerance (IGT) and nonalcoholic fatty liver. The second was to make a rule regarding to whom 75-g oral glucose tolerance tests (OGTTs) should be applied to identify subjects with IGT and diabetes mellitus (DM) in the annual check-up at the human dry dock.

METHODS

A total of 716 subjects who visited the Department of General Medicine of the International Medical Center of Japan from May 2001 through January 2008 for an annual check-up at the human dry dock were analyzed. We evaluated risk factors related to nonalcoholic fatty liver using multivariate logistic regression analysis and compared the difference of body mass index (BMI) and glucose level at 75-g OGTT at two different time points in subjects whose fatty change had improved or worsened.

RESULTS

Nonalcoholic fatty liver was strongly related to 2-h- and 1-h-post-challenge glucose level (P<0.0001 and P=0.018, respectively), but not fasting plasma glucose (FPG) (P=0.706). The risk factors for IGT were nonalcoholic fatty liver (P<0.05), low levels of high-density lipoprotein cholesterol (HDL-C) (P=0.026) and age (P=0.013). A clearly positive relationship was observed between the difference of BMI and 2-h-post-challenge glucose level among the subjects whose fatty change had improved or worsened (R=0.6, P=0.018).

CONCLUSIONS

Nonalcoholic fatty liver was clearly related to the 2-h- or 1-h-post-challenge glucose level, but not to FPG, in 75-g OGTT, and this IGT was corrected by body weight reduction in accordance with diminished nonalcoholic fatty liver. Thus, 75-g OGTT should be applied to subjects with nonalcoholic fatty liver to evaluate IGT.

Insulin resistance is a major determinant of sustained virological response in genotype 1 chronic hepatitis C patients receiving peginterferon alpha-2b plus ribavirin

BACKGROUND

Cross-sectional studies suggest insulin resistance is strongly associated with hepatic steatosis and fibrosis in patients with chronic hepatitis C (CHC), which might affect the efficacy of antiviral therapy. Aim To investigate retrospectively the impact of insulin resistance on treatment response in Chinese genotype 1 CHC patients receiving a 24-week course therapy with peginterferon alpha-2b/ribavirin.

METHODS

A total of 133 biopsy-proven CHC patients were enrolled for analyses. Insulin resistance was evaluated by homeostasis model assessment of insulin resistance (HOMA-IR). Hepatic fibrosis was graded by the METAVIR scoring system.

RESULTS

Mean HOMA-IR progressively elevated along with the severity of hepatic fibrosis (F1-F2 fibrosis: 2.55 +/- 0.16 vs. F3-F4 fibrosis: 3.61 +/- 0.20, P < 0.001). Compared with patients with sustained virological response (SVR), patients without SVR had significantly higher percentages of F3-F4 fibrosis (62.2% vs. 21.6%, P < 0.001) and baseline high viral load (>or=600,000 IU/mL; 64.4% vs. 35.6%, P = 0.038). In addition, patients without SVR had significantly higher plasma levels of insulin (15.03 +/- 0.89 vs. 10.19 +/- 0.55 microU/mL, P < 0.001) and HOMA-IR values (3.76 +/- 0.23 vs. 2.50 +/- 0.15, P < 0.001). Multivariate analyses showed that F1-F2 fibrosis (odds ratio: 4.49, P = 0.001), HOMA-IR < 2 (odds ratio: 7.15, P = 0.005) and pre-treatment hepatitis C virus RNA < 600,000 IU/mL (odds ratio: 3.26, P = 0.012) were the independent factors associated with SVR.

CONCLUSIONS

Insulin resistance is a major determinant of SVR in genotype 1 CHC patients receiving peginterferon alpha-2b/ribavirin. Strategies to modify insulin resistance may be effective in enhancing SVR before or during anti-viral therapy.

Decreased hepatic RBP4 secretion is correlated with reduced hepatic glucose production but is not associated with insulin resistance in patients with liver cirrhosis

OBJECTIVE

Patients with liver cirrhosis have a high incidence of insulin resistance and diabetes. This study was designed to determine circulating levels and hepatic production of retinol-binding protein 4 (RBP4) in relation to parameters of hepatic and systemic metabolism in patients with liver cirrhosis.

DESIGN AND METHOD

Circulating RBP4 levels were measured in 19 patients with liver cirrhosis at different clinical stages of the disease and in 20 age-, sex- and body mass index (BMI)-matched controls. Hepatic production rates of RBP4 and glucose were assessed by measuring the arterial hepatic venous concentration difference together with hepatic blood flow. Insulin resistance was determined by the Quantitative Insulin Sensitivity Check Index (QUICKI) and the homeostasis model assessment of insulin resistance (HOMA-IR), energy expenditure by indirect calorimetry and body composition by bioelectrical impedance analysis (BIA).

RESULTS

Compared with controls, RBP4 levels in cirrhosis were decreased (8.1 +/- 1.8 vs. 22.6 +/- 2.4 mg/l, P < 0.001) due to decreased hepatic production (P < 0.05). RBP4 correlated with hepatic protein synthesis capacity (P < 0.01), but not with insulin resistance, energy expenditure, BMI or body fat mass. Plasma RBP4 correlated with hepatic glucose production (P < 0.05).

CONCLUSIONS

These data demonstrate that RBP4 in cirrhosis (i) is decreased due to reduced hepatic production, (ii) is not associated with insulin resistance, and (iii) might have a beneficial role by decreasing hepatic glucose production and could thus also be regarded as a hepatokine.

Insulin resistance and hepatitis C virus: a case-control study of non-obese, non-alcoholic and non-steatotic hepatitis virus carriers with persistently normal serum aminotransferase

BACKGROUND/AIMS

Recent studies using transgenic mouse models have demonstrated that the presence of hepatitis C virus (HCV) singularly induces insulin resistance (IR). When evaluated in humans, the exclusion of other factors influencing IR, such as obesity, alcohol intake, hepatic inflammation and steatosis is needed, but only few studies have been performed to these ends. Therefore, we aimed at exploring the singular effects of HCV on glucose metabolism through analysis of HCV carriers with persistently normal serum aminotransferase.

METHODS

Non-obese, non-diabetic and non-alcoholic HCV carriers (n=30) were enrolled with 30 hepatitis B virus carriers matched by age, gender, body mass index and waist-to-hip ratio. All patients maintained normal serum aminotransferase (<30 U/L), hyaluronic acid (<50 ng/ml) and platelet count (>150 x 10(3)/microl) for more than 5 years without additional treatments, and had no signs of steatosis. We then compared fasting plasma glucose, serum insulin and adiponectin, and homoeostasis model assessment of IR (HOMA-IR) and HOMA-beta indices between the groups.

RESULTS

There were no significant differences in IR/secretion-associated markers or serum adiponectin. Multivariate analysis demonstrated that the presence of HCV was not an independent predictor of IR. HOMA-IR was strongly correlated with waist circumferences and serum gamma-glutamyltransferase in HCV carriers, but not with serum aminotransferase, high-sensitivity C-reactive protein, hyaluronic acid or HCV core antigen.

CONCLUSIONS

These results suggest that the presence of HCV alone does not affect IR. Coexistence of hepatitis, steatosis and/or fibrosis may be important to the pathogenesis of IR induced by chronic HCV infection.

Transplant-associated hyperglycemia

As patient survival after solid organ transplantation continues to improve, comorbidites associated with chronic hyperglycemia will assume increasing importance in limiting outcomes and quality of life. New-onset diabetes mellitus commonly occurs in the posttransplant setting and is associated with multiple complications including graft loss, cardiovascular disease, infection, and death. Furthermore, recent studies have begun to highlight the very high posttransplant prevalence and the significant cardiovascular implications of the prediabetic states of impaired fasting glucose and impaired glucose tolerance, indicating that the overall burden of transplantation-associated hyperglycemia is far greater than previously appreciated. Shared and distinct pathogenic factors and clinical repercussions exist among the organ-specific transplant scenarios. Diabetogenic immunosuppressive agents are common to all organ transplant settings, whereas glucose regulation is also strained by the restoration of failed hepatic and renal function. The atherogenic properties of hyperglycemia are particularly significant in the kidney transplant population, which has a marked predisposition to cardiovascular disease, whereas accelerated cardiac allograft vasculopathy and liver fibrosis have been associated with hyperglycemia in the heart and liver transplant settings, respectively. Aggressive screening will effectively detect transplant-associated hyperglycemia, whereas risk factor modification, lifestyle intervention and, where appropriate, drug therapy, may decrease its impact. Topics of future investigation should include the use of emerging diabetes therapies and avenues for the prevention and reversal of transplant-associated hyperglycemia.

Effect of sustained virological response to treatment on the incidence of abnormal glucose values in chronic hepatitis C

BACKGROUND/AIMS

To investigate the effect of sustained virological response (SVR) on impaired fasting glucose (IFG) and/or type 2 diabetes (T2DM); to assess the influence of glucose abnormalities on the SVR rate.

METHODS

1059 patients with chronic HCV; normal glucose (< 100 mg/dl) in 734, IFG (between 100 and 125 mg/dl) in 218, and T2DM (126 mg/dl) in 107 cases, were treated with interferon plus ribavirin over 24 or 48 weeks, depending on viral genotype.

RESULTS

The SVR rate was lower in patients with IFG and/or T2DM than in patients with normal glucose concentrations [143/325 (44%) vs. 432/734 (58.8%); P=0.002]. In the follow-up, abnormal glucose concentrations were observed in 74 of 304 (24.3%) non-responders and in 49 of 430 (11.4%) sustained responders (log-rank: 13.8; P=0.00002). Reverse stepwise logistic regression analysis identified the independent variables predictive of IFG or T2DM development as: sustained response (OR: 0.44; 95%CI=0.20-0.97; P=0.004) and fibrosis stage (OR: 1.46; 95%CI=1.06-2.01;P=0.02). Family history of DM, steatosis, gender, HCV viral load, genotype, triglycerides, cholesterol and BMI did not enter the multivariate analysis equation.

CONCLUSIONS

SVR reduces the risk of IFG and/or T2DM development in patients with chronic hepatitis C while altered glucose metabolism impairs sustained response to viral treatment.

Insulin resistance in chronic hepatitis C: association with genotypes 1 and 4, serum HCV RNA level, and liver fibrosis

BACKGROUND & AIMS

Our study was designed to test the association between insulin resistance (IR) and hepatitis C virus (HCV) genotypes, serum HCV RNA level and liver fibrosis stage in a large prospective cohort of chronic hepatitis C (CHC) patients.

METHODS

Six hundred consecutive patients (CHC, n = 500; chronic hepatitis B (CHB), n = 100) were evaluated on the day of liver biopsy. IR (Homeostasis Model for Assessment of Insulin Resistance) and all components of the metabolic syndrome were assessed. By logistic regression, independent factors associated with IR and those associated with significant fibrosis were assessed in nondiabetic and noncirrhotic CHC, respectively. Parameters of IR were compared between hepatitis B and 240 CHC matched by epidemiologic, metabolic, and histologic features.

RESULTS

IR was present in 32.4% of the 462 nondiabetic CHC and associated with the metabolic syndrome, genotypes 1 and 4, significant fibrosis, and severe steatosis. IR was diagnosed in 15% of 145 CHC without metabolic syndrome or significant fibrosis, and associated with genotypes 1 and 4, high serum HCV RNA level, and moderate-severe necroinflammation. Significant fibrosis was present in 51.1% of the 454 noncirrhotic CHC patients and associated with male sex, age >40 years, IR, moderate-severe necroinflammation, and severe steatosis. IR was less frequent in CHB than in matched CHC (5% vs 35%, respectively, P < .001).

CONCLUSIONS

IR is a specific feature of CHC, associated with genotypes 1 and 4 and high serum HCV RNA level. Significant fibrosis is associated with IR independent from steatosis.

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.

Hepatitis C and insulin resistance: mutual interactions. A review

Worldwide approximately 200 million people are chronically infected with hepatitis C virus (HCV). Chronic HCV infection represents the leading cause of liver cirrhosis and the main indication for liver transplantation in the western world. In addition, chronic HCV infection is associated with numerous clinical manifestations, including type 2 diabetes. An obvious and frequently suggested explanation for the connection between HCV infection and type 2 diabetes is that cirrhosis by itself causes insulin resistance. However, the prevalence of type 2 diabetes in HCV cirrhosis is higher than in HBV cirrhosis (23.6% vs 9.4%). This suggests that HCV infection by itself can lead to insulin resistance and predispose to the onset of type 2 diabetes. First, HCV core protein induces hepatic steatosis by inhibition of microsomal triglyceride transfer protein and hepatic steatosis causes insulin resistance. Secondly, HCV core protein inhibits, through elevation of TNF-alfa and other factors, the insulin-signalling pathways causing insulin resistance. Moreover, recent data strongly suggest that insulin resistance is an important predictor of poor response to antiviral therapy in chronic hepatitis patients treated with peginterferon plus ribavirin.

Insulin resistance and hepatitis C

Insulin resistance is the major feature of the metabolic syndrome and depends on insulin secretion and insulin sensitivity. In chronic hepatitis C, insulin resistance and type 2 diabetes mellitus are more often seen than in healthy controls or chronic hepatitis B patients. Hepatitis C virus (HCV) infection promotes insulin resistance, mainly by increased TNF production together with enhancement of suppressor of cytokine (SOC-3); both events block PI3K and Akt phosphorylation. Two types of insulin resistance could be found in chronic hepatitis C patients: “viral” and “metabolic” insulin resistance. Insulin resistance in chronic hepatitis C is relevant because it promotes steatosis and fibrosis. The mechanisms by which insulin resistance promotes fibrosis progression include: (1) steatosis, (2) hyperleptinemia, (3) increased TNF production, (4) impaired expression of PPARγ receptors. Lastly, insulin resistance has been found as a common denominator in patients difficult-to-treat like cirrhotics, overweight, HIV coinfected and Afro-American. Insulin resistance together with fibrosis and genotype has been found to be independently associated with impaired response rate to peginterferon plus ribavirin. Indeed, in genotype 1, the sustained response rate was twice (60%) in patients with HOMA ≤ 2 than patients with HOMA > 2. In experiments carried out on Huh-7 cells transfected by full length HCVRNA, interferon alpha blocks HCV replication. However, when insulin (at doses of 128 μU/mL, similar that seen in the hyperinsulinemic state) was added to interferon, the ability to block HCV replication disappeared, and the PKR synthesis was abolished. In summary, hepatitis C promotes insulin resistance and insulin resistance induces interferon resistance, steatosis and fibrosis progression.

Elevated resistin levels in cirrhosis are associated with the proinflammatory state and altered hepatic glucose metabolism but not with insulin resistance

The adipokine resistin has been implicated in obesity and insulin resistance. Liver cirrhosis is associated with decreased body fat mass and insulin resistance. We determined plasma resistin levels in 57 patients with cirrhosis, 13 after liver transplantation, and 30 controls and correlated these with hemodynamic as well as hepatic and systemic metabolic parameters. Patients with cirrhosis had, dependent on the clinical stage, an overall 86% increase in resistin levels (P < 0.001) with hepatic venous resistin being higher than arterial levels (P < 0.001). Circulating resistin was significantly correlated with plasma TNF-alpha levels (r = 0.62, P < 0.001). No correlation was observed between resistin and hepatic hemodynamics, body fat mass, systemic energy metabolism, and the degree of insulin resistance. However, plasma resistin in cirrhosis was negatively associated with hepatic glucose production (r = -0.47, P < 0.01) and positively with circulating free fatty acids (FFA; r = 0.40, P < 0.01) and ketone bodies (r = 0.48, P < 0.001) as well as hepatic ketone body production (r = 0.40, P < 0.01). After liver transplantation, plasma resistin levels remained unchanged, whereas insulin resistance was significantly improved (P < 0.01). These data provide novel insights into the role of resistin in the pathophysiological background of a catabolic disease in humans and also indicate that resistin inhibition may not represent a suitable therapeutic strategy for the treatment of insulin resistance and diabetes in patients with liver cirrhosis.

Oral glucose tolerance test predicts prognosis of patients with liver cirrhosis

OBJECTIVE

The aim of this study was to evaluate whether oral glucose tolerance test (OGTT) was useful in evaluating the prognosis of patients with liver cirrhosis.

METHODS

Fifty-six patients with liver cirrhosis were enrolled in a prospective cohort study. In all cases, glucose tolerance was diagnosed by a 75-g OGTT according to World Health Organization (WHO) criteria. The relationship of clinical variables to the cirrhosis-related prognosis was investigated using univariate and multivariate regression models.

RESULTS

Diabetes mellitus (DM) was diagnosed in 21 subjects (38%), impaired glucose tolerance (IGT) in 13 subjects (23%), and normal glucose tolerance (NGT) in 22 subjects (39%) using OGTT. The cumulative survival rates of patients with liver cirrhosis and NGT were 94.7% at 5 yr; liver cirrhosis and IGT, 68.8% at 5 yr; liver cirrhosis and DM, 56.6% at 5 yr. The survival rates of patients with liver cirrhosis and DM significantly differed from those with NGT. Univariate analysis demonstrated that serum albumin, total bilirubin, prothrombin activity, Child-Pugh scores, and glucose intolerance were highly significant prognostic factors. Multiple regression analysis yielded albumin and DM as the most powerful independent negative predictors of survival.

CONCLUSIONS

OGTT appears to be useful for evaluating the prognosis of cirrhotic patients.

Review article: an unexpected virus-host interaction--the hepatitis C virus-diabetes link

There is now consistent epidemiological evidence for an association between chronic hepatitis C and diabetes. Important, although so far limited longitudinal data, have documented an increased risk for diabetes in patients infected by hepatitis C virus (HCV) especially in those with metabolic risk factors such as a high BMI and older age. HCV encoded proteins might alter insulin signalling thus explaining impaired insulin sensitivity and the occurrence of glycaemic dysregulation even before the cirrhotic stage. The consequences of the association between diabetes and HCV infection are an increased liver fibrosis stage and faster fibrosis progression rate. This article reviews recent human and experimental data on the HCV-diabetes association.

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.

Prevalence of type 2 diabetes mellitus in Brazilian liver transplant candidates: Negative association with HCV status

Recently, an epidemiological association between hepatitis C virus (HCV) infection and type 2 diabetes mellitus (DM) has been reported in several studies, although many of them did not consider known risk factors in the pathogenesis of type 2 DM. The aim of this study was to assess the prevalence of type 2 DM among Brazilian HCV (+) and HCV (-) liver transplant candidates, analyzing known confounding factors for the development of type 2 DM. We conducted a cross-sectional study to evaluate the prevalence of type 2 DM among 106 liver transplant adult candidates, comparing 36 HCV (+) cirrhotic patients with 70 HCV (-) patients who developed cirrhosis from other causes. Type 2 DM was diagnosed after two consecutive fasting glucose values > or =126 mg/dL. The age, sex, and race distribution, severity of liver disease (Child-Pugh score), and family history of DM were similar in both groups, but the mean body mass index (BMI) was higher in the HCV (-) subjects (26.81 +/- 5.29 vs 24.0 +/- 4.71, P < .01) Most of the patients were Caucasians (70.75%). Type 2 DM was detected in 36.11% of HCV (+) group and in 25.71% of the HCV (-) (P = .27). A multivariate analysis revealed that family history of DM was the only significant independent predictor for DM (odds ratio = 2.55, 95% CI = 1.03 to 6.31, P = .04). In conclusion, our study did not show an association between HCV infection and Type 2 DM in Brazilian liver transplant candidates. It confirmed that the family history of DM was a determinant factor for the development of type 2 DM.

Alterations in glucose metabolism associated with liver cirrhosis persist in the clinically stable long-term course after liver transplantation

With increasing long-term survival rates after orthotopic liver transplantation (OLT), metabolic alterations complicating the clinical course, such as diabetes mellitus (DM), become increasingly important. Liver cirrhosis is associated with severe alterations in glucose metabolism. However, it is currently unclear whether these changes are reversed by successful OLT. We therefore characterized glucose metabolism in patients with liver cirrhosis and normal fasting glucose levels before OLT (cir), in the clinically stable long-term course after OLT (OLT), and control subjects (con) using oral glucose tolerance tests (cir = 100, OLT = 62, con = 32), euglycemic-hyperinsulinemic clamps (cir = 10, OLT = 27, con = 14), and positron emission tomography (PET) scan analysis with 18F-fluorodeoxyglucose (FDG) as a tracer (cir = 7, OLT = 7, con = 5). Fasting insulin and C-peptide levels were significantly elevated in patients with liver cirrhosis compared with both control subjects (P <.001) and patients after OLT (P <.001). After OLT, insulin was normalized, whereas C-peptide remained elevated (P < 0.01). In the patients with liver cirrhosis, 27% had a normal glucose tolerance, 38% had an impaired glucose tolerance (IGT), and 35% were diabetic. After OLT, 34% had a normal glucose tolerance, 29% an IGT, and 37% were diabetic. Comparison of the same patients before and after OLT demonstrated that IGT or diabetes before OLT was the major risk factor for these conditions after OLT, which was independent of either immunosuppression (cyclosporine vs FK506) or low-dose prednisolone. Total glucose uptake was reduced in patients with liver cirrhosis to less than half the values in control subjects (21.2 +/- 2.8 vs 43.7 +/- 2.4 micromol/kg/minute, respectively, P <.001), whereas patients after OLT showed intermediate values (35.7 +/- 1.4 micromol/kg/minute, P < 0.05 vs con, P < 0.01 vs cir). This difference was caused by a reduction in nonoxidative glucose metabolism in patients with liver cirrhosis compared with control subjects (7.4 +/- 1.9 vs 28.7 +/- 1.8 micromol/kg/minute, respectively, P <.01) and patients after OLT (20.1 +/- 1.4 micromol/kg/minute, P < 0.05 vs con and OLT). In the PET study, skeletal muscle glucose uptake was significantly reduced in patients with liver cirrhosis compared with control subjects (3.5 +/- 0.4 vs 11.8 +/- 2.5 micromol/100g/minute, respectively, P <.05). After OLT, muscle glucose uptake improved compared with patients with liver cirrhosis (5.9 +/- 1.0 micromol/100g/minute, P <.05) but remained significantly lower than in control subjects (P <.05). In conclusion, these results demonstrate that preexisting IGT or diabetes are the major risk factors for IGT and diabetes after OLT. This finding was independent of the immunosuppressive medication. The peripheral insulin resistance in cirrhosis is characterized by a decrease in nonoxidative glucose disposal that is improved, but not normalized, after OLT.

Insulin resistance and insulin secretion in chronic hepatitis C virus infection

BACKGROUND/AIMS

Diabetes mellitus (DM) is frequently observed in patients with chronic hepatitis caused by hepatitis C virus infection (CHC). The present study was designed to determine the pathogenic factors responsible for glucose intolerance in CHC patients.

METHODS

A total of 131 patients with CHC were enrolled in this study. Insulin resistance and beta-cell function were determined after 75 g oral glucose tolerance tests.

RESULTS

Glucose intolerance was detected in 27.5% (36/131) of CHC patients; 10 had DM and 26 impaired glucose tolerance. HOMA-R [insulin 0xglucose 0/22.5] was greater in patients with both impaired glucose tolerance and DM than in those with normal glucose tolerance (P<0.01). Matsuda index [10(4)/ (square root) (mean insulinxmean glucosexglucose 0xinsulin 0)] was lower in diabetic patients than in those with normal glucose tolerance (P<0.05). The insulinogenic index [Deltainsulin 30-0/Deltaglucose 30-0] and DeltaC-peptide 30 [DeltaC-peptide 30-0/Deltaglucose 30-0] were significantly lower even in patients with impaired glucose tolerance than in patients with normal glucose tolerance (P<0.01).

CONCLUSIONS

Both insulin resistance and beta-cell dysfunction contribute to glucose intolerance in CHC patients.

Hepatitis C virus is independently associated with increased insulin resistance after liver transplantation

BACKGROUND AND AIMS

There is a strong epidemiologic association between diabetes mellitus (DM) and hepatitis C virus (HCV) infection. However, the pathogenetic basis for this association has not been established. We sought to evaluate the association between insulin resistance (IR), beta-cell dysfunction, and HCV among orthotopic liver transplant (OLT) recipients.

METHODS

We performed a cross sectional analysis comparing 39 HCV(+) with 60 HCV(-) OLT recipients. IR and beta-cell function were calculated using validated measures and were correlated with clinical variables.

RESULTS

By multivariate analysis of the entire cohort, HCV infection and body mass index (BMI) were independent predictors of IR (P =0.04 and 0.0006, respectively). HCV infection was associated with 35% increase in IR. Because the model used to calculate IR was derived from nondiabetic subjects, we performed additional analysis of patients who did not meet criteria for diabetes at the time of their study evaluation. In this analysis, HCV(+) subjects had greater fasting insulin and homeostasis model assessment (HOMA) IR (15.3 mu U/mL and 3.8) compared with HCV(-) patients (10.7 mu U/mL and 2.5) (P =0.03, 0.03). There was no difference in beta-cell function or hepatic insulin extraction between the HCV (+) and (-) groups. HCV (P =0.0005), BMI (P <0.0001), and high high-density lipoprotein (P =0.039) were the only independent predictors of IR. The presence of HCV infection and a 10-fold increase in HCV RNA were associated with a 62% and 8% increase in IR, respectively.

CONCLUSIONS

HCV is independently associated with increased IR after OLT. These findings provide a possible pathogenetic basis for the association of DM with HCV.