Edmondo Falleti

Hyperglycemia-Induced Thrombin Formation in Diabetes: The Possible Role of Oxidative Stress

Diabetes is characterized by the existence of a thrombosis-prone condition, possibly related to hyperglycemia. However, the mechanism linking hyperglycemia to the activation of the coagulation cascade is still unclear. It has been recently suggested that diabetes is accompanied by increased oxidative stress. In this work, the possibility that oxidative stress may be involved in the hyperglycemia-induced coagulation activation has been evaluated. Prothrombin fragment 1 + 2 (F1+2), which represents a reliable marker of the amount of thrombin released in the circulation, has been chosen for studying thrombin formation in vivo. In nine type II diabetic patients and in seven healthy control subjects, matched for age and body mass index, three different experiments were performed: oral glucose tolerance test (OGTT), intravenous antioxidant glutathione (GSH) administration for 2 h, and OGTT plus intravenous GSH administration. Samples were drawn at −15 min and every 30 min from 0 to 180 min. During the OGTT, F1+2 significantly increased in both diabetic and healthy subjects. GSH administration during OGTT normalized this phenomenon. GSH administered alone significantly decreased F1+2 in diabetic patients, while no effect was observed in the normal subjects. These data suggest that hyperglycemia may induce thrombin activation, possibly inducing an oxidative stress, and that antioxidant GSH may counterbalance this effect.

Total Radical-Trapping Antioxidant Parameter in NIDDM Patients

OBJECTIVE The existence of an oxidative stress in diabetes is still debated. This is largely due to the lack of good tools to assay the level of oxidative stress. The use of total radical-trapping antioxidant parameter (TRAP) has recently been proposed to explore the antioxidant property of a plasma sample. TRAP may be either directly measured by a fluorescence-based method (TRAPm) or calculated (TRAPc) by a mathematical formula, taking into account the serum levels of four natural antioxidants: protein-bound SH (thiol) groups, uric acid, vitamin E, and vitamin C. The difference between TRAPm and TRAPc is due to antioxidants, which are still unidentified, and to the possible synergism among the antioxidants. RESEARCH DESIGN AND METHODS In this study, we evaluated malondialdehyde (MDA), TRAPm, TRAPc, protein-bound SH groups, uric acid, vitamin E, and vitamin C in 40 NIDDM patients and 40 matched normal control subjects. RESULTS TRAPm and TRAPc were significantly lower in diabetic patients. A good correlation between TRAPm and TRAPc was found in both NIDDM patients (r = 0.68, P < 0.0001) and control subjects (r = 0.74, P < 0.0001). Protein-bound SH groups and uric acid were significantly lower in diabetic subjects, while MDA and vitamin E level were significantly higher. After correction for serum triglycerides (MDA) and cholesterol (vitamin E), MDA lost significance, while vitamin E did not. Vitamin C was not different in the two groups. CONCLUSIONS These data show decreased TRAP levels in NIDDM patients, suggesting the existence of lower antioxidant defenses in diabetes. The decrease appears to be due to various antioxidants, some of them not yet clearly defined. TRAP may represent a more reliable estimation of serum antioxidant capacity than the measurement of each known antioxidants. The correlation found between TRAPm and TRAPc values suggests that TRAPc, easier to measure than TRAPm, might be adequately reliable for routine assessment of oxidative stress in diabetic patients.

IL-28B rs12979860 C/T allele distribution in patients with liver cirrhosis: Role in the course of chronic viral hepatitis and the development of HCC

BACKGROUND & AIMS A single nucleotide polymorphism (rs12979860 C/T) 3kb upstream of the interleukin 28B (IL-28B) gene was shown to be associated with hepatitis C clearance. We verified whether this association also translates into a different genotype distribution at the end of the disease trajectory. METHODS A RFLP-PCR technique was used to genotype 412 patients with cirrhosis due to hepatitis C (n=199), hepatitis B (n=75), alcohol (n=110), and other causes (n=28), of whom 256 underwent liver transplantation (OLT). Hepatocellular carcinoma (HCC) was demonstrated in the native liver of 85 OLT patients, 52 with viral cirrhosis, and 33 with non-viral cirrhosis respectively. A group of 292 patients (235 HCV and 57 HBV positive) with mild chronic hepatitis and 344 healthy subjects served as controls. RESULTS A significant difference (p=0.0005) was observed in IL-28B rs12979860 genotype frequencies between patients with viral cirrhosis (C/C=99, C/T=137, T/T=38) and those with non-viral cirrhosis (C/C=72, C/T=58, T/T=8). Patients with HCV related cirrhosis carried more frequently the T/T genotype in comparison to mild hepatitis C or HBV-related cirrhosis. IL-28B rs12979860 genotype frequencies were C/C=23, C/T=50, T/T=12 among OLT patients with cirrhosis complicated by HCC, and C/C=79, C/T=78, T/T=14 among patients with cirrhosis not complicated by HCC (p<0.005). CONCLUSIONS IL-28B rs12979860 C/T polymorphism T allele is more prevalent in patients with viral cirrhosis due to HCV in comparison to other aetiologies and to patients with mild chronic hepatitis C. Among OLT patients, carriage of this allele seems to augment the risk of developing HCC.

Association between the PNPLA3 (rs738409 C>G) variant and hepatocellular carcinoma: Evidence from a meta-analysis of individual participant data.

The incidence of hepatocellular carcinoma (HCC) is increasing in Western countries. Although several clinical factors have been identified, many individuals never develop HCC, suggesting a genetic susceptibility. However, to date, only a few single‐nucleotide polymorphisms have been reproducibly shown to be linked to HCC onset. A variant (rs738409 C>G, encoding for p.I148M) in the PNPLA3 gene is associated with liver damage in chronic liver diseases. Interestingly, several studies have reported that the minor rs738409[G] allele is more represented in HCC cases in chronic hepatitis C (CHC) and alcoholic liver disease (ALD). However, a significant association with HCC related to CHC has not been consistently observed, and the strength of the association between rs738409 and HCC remains unclear. We performed a meta‐analysis of individual participant data including 2,503 European patients with cirrhosis to assess the association between rs738409 and HCC, particularly in ALD and CHC. We found that rs738409 was strongly associated with overall HCC (odds ratio [OR] per G allele, additive model = 1.77; 95% confidence interval [CI]: 1.42‐2.19; P = 2.78 × 10−7). This association was more pronounced in ALD (OR = 2.20; 95% CI: 1.80‐2.67; P = 4.71 × 10−15) than in CHC patients (OR = 1.55; 95% CI: 1.03‐2.34; P = 3.52 × 10−2). After adjustment for age, sex, and body mass index, the variant remained strongly associated with HCC. Conclusion: Overall, these results suggest that rs738409 exerts a marked influence on hepatocarcinogenesis in patients with cirrhosis of European descent and provide a strong argument for performing further mechanistic studies to better understand the role of PNPLA3 in HCC development. (Hepatology 2014;59:2170–2177)

Complementary role of vitamin D deficiency and the interleukin-28B rs12979860 C/T polymorphism in predicting antiviral response in chronic hepatitis C.

The widely accepted interleukin‐28B (IL‐28B) rs12979860 C/T polymorphism and the more recently proposed vitamin D serum concentration are two novel predictors of the response to antiviral treatment in chronic hepatitis C virus (HCV) infection. This study aimed to verify whether the IL‐28B rs12979860 C/T polymorphism and pretreatment serum vitamin D levels have independent or complementary roles in predicting the rates of sustained viral response (SVR). The present study included 211 consecutive, treatment‐naïve chronic HCV patients who had their pretreatment serum 25‐OH vitamin D level and IL‐28B rs12979860 C/T genotype determined. Overall, SVR was achieved by 134/211 (63.5%) patients and by 47/110 (42.7%) patients infected with difficult‐to‐treat HCV genotypes. On multivariate analysis, SVR was predicted by the HCV genotype, the IL‐28B rs12979860 C/T polymorphism, and gamma‐glutamyl transpeptidase, HCV RNA, cholesterol, and 25‐OH vitamin D serum levels, with an area under the receiver operating characteristic (ROC) curve of 0.827. When difficult‐to‐treat HCV genotypes were analyzed separately, the SVR was predicted by the IL‐28B rs12979860 C/T polymorphism, viral load, and serum vitamin D level, with an area under the ROC curve of 0.836. Moreover, by categorizing these latter patients into four groups—C/C homozygotes with vitamin D levels >20 ng/mL (group A) or ≤20 ng/mL (group B) and C/T heterozygotes or T/T homozygotes with vitamin D levels >20 ng/mL (group C) or ≤20 ng/mL (group D)—a significant linear trend was observed, with SVR rates in the following descending order: group A, 18/21 (85.7%); group B, 6/11 (54.5%); group C, 14/38 (36.8%); and group D, 9/40 (22.5%) (P < 0.0001). Conclusion: Vitamin D serum levels are complementary to the IL‐28B rs12979860 C/T polymorphism in enhancing the correct prediction of the SVR in treatment‐naïve chronic hepatitis C. (HEPATOLOGY 2011;)

Vitamin D supplementation improves response to antiviral treatment for recurrent hepatitis C.

In immune‐competent patients, higher vitamin D levels predicted sustained viral response (SVR) following interferon (INF) and ribavirin therapy for chronic hepatitis C. This study aimed to verify the influence of vitamin D serum levels and/or vitamin D supplementation in predicting SVR rates for recurrent hepatitis C (RHC). Forty‐two consecutive patients were treated for RHC with combination therapy with INF‐α and ribavirin for 48 weeks. Vitamin D serum levels were measured in all patients before antiviral therapy. In 15 patients oral vitamin D3 supplementation was administered to avoid further bone loss. SVR was observed in 13 patients; it was achieved in 1/10 severely vitamin D deficient (≤10 ng/ml) patients, in 6/20 deficient (>10 and ≤20 ng/ml) and in 6/12 with near normal (>20 ng/ml) 25‐OH vitamin D serum levels (P < 0.05). Cholecalciferol supplementation, in the presence of a normal or near normal baseline vitamin D concentration, (improvement of chi‐square P < 0.05, odds ratio 2.22) and possessing a genotype other than 1 (improvement of chi‐square P < 0.05, odds ratio 3.383) were the only variables independently associated to SVR. In conclusion, vitamin D deficiency predicts an unfavourable response to antiviral treatment of RHC. Vitamin D supplementation improves the probability of achieving a SVR following antiviral treatment.

Increased Circulating Intercellular Adhesion Molecule-1 Levels in Type II Diabetic Patients: The Possible Role of Metabolic Control and Oxidative Stress

Blood levels of the circulating form of the integrin intercellular adhesion molecule-1 (ICAM-1), malondialdehyde (MDA), and hemoglobin A1c (HbA1c) were studied at baseline and 3 months after improved metabolic control in 25 type II diabetic patients without signs of macroangiopathy, and were compared with those in 15 matched healthy normal controls. Circulating ICAM-1 and MDA levels were increased in diabetic patients, both at baseline and 3 months later. However, with improving metabolic control HbA1c, circulating ICAM-1, and MDA significantly decreased. A significant correlation between circulating ICAM-1, HbA1c, and MDA was found in diabetic patients at each time. Multiple regression analysis considering circulating ICAM-1 as the dependent variable and HbA1c and MDA as independent variables, showed a significant correlation between the three variable at each time. Similar correlations were found in control subjects. These data show increased levels of circulating ICAM-1 in type II diabetic patients, independent of the presence of macroangiopathy. Moreover, these results suggest that oxidative stress and metabolic control might participate in determining increased circulating ICAM-1 levels in both type II diabetic patients and normal subjects.

PNPLA3 rs738409C/G polymorphism in cirrhosis: relationship with the aetiology of liver disease and hepatocellular carcinoma occurrence.

Background and aim: The PNPLA3 rs738409 C>G polymorphism has been found to be strongly associated with non‐alcoholic fatty liver disease and with alcoholic liver disease. Whether the PNPLA3 rs738409 polymorphism could be a risk factor for the development of hepatocellular carcinoma (HCC) in cirrhosis patients is unknown.

Blood lipids of patients with chronic hepatitis: differences related to viral etiology

In order to investigate whether a difference might exist in blood cholesterol and its subtractions between patients with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, serum cholesterol, HDL-cholesterol, triglycerides and common liver function tests were measured in 138 patients (92 male, 46 female) with biopsy-proven chronic viral hepatitis without cirrhosis. Twenty-four had hepatitis B and 114 hepatitis C. Mean serum cholesterol was lower in HCV-infected in comparison to HBV-infected patients (175 +/- 36 mg/dl vs. 189 +/- 28 mg/dl, p < 0.05). On multivariate analysis, etiology of hepatitis appeared to be associated with the value of serum cholesterol, independently of age, sex and liver synthetic function (improvement of chi-square 4.40, p < 0.05). In patients with HBV infection, circulating tumor necrosis factor-alpha demonstrated a correlation with serum triglycerides (p = 0.618) and an inverse correlation with serum HDL-cholesterol (p = -0.456); in the group of patients with HCV infection, interleukin-6 correlated with triglycerides (p = 0.370) and HDL-cholesterol (p = -0.355). Thus, differences in the mechanisms of liver damage and of viral clearance in hepatitis C in comparison to hepatitis B, reflected in these patients by the levels of circulating cytokines, may be mirrored by differences in their blood lipid composition.

Fibrinogen Plasma Levels as a Marker of Thrombin Activation in Diabetes

This study attempted to verify the existence of a correlation between fibrinogen, a major cardiovascular risk factor in diabetes, and indexes of thrombin generation and action, prothrombin fragment 1 + 2 (F1 + 2), and D-dimer (D-D), in a group of diabetic subjects compared with a matched control group. Forty insulin-dependent diabetes mellitus patients and 30 matched healthy control subjects participated in this study. The subjects were tested for the following parameters: fibrinogen, prothrombin F1 + 2, D-D, fasting glycemia, and HbA1c. In addition, 5 diabetic subjects who maintained stable fibrinogen plasma levels > 300 mg/dl for at least 6 months before the study were treated with 12,500 U/day subcutaneous heparin for 7 days. Diabetic subjects showed increased levels of fibrinogen, prothrombin F1 + 2, and D-D plasma levels. Simple linear regression analysis detected a positive correlation between fibrinogen and prothrombin F1 + 2, D-D, and glycosylated HbA1c. In the five diabetic subjects treated with heparin fibrinogen, prothrombin F1 + 2 and D-D levels decreased at the end of the treatment. All these parameters returned to baseline after 7 days of washout. These data indicate that fibrinogen plasma levels are correlated to parameters of thrombin activation in plasma in diabetic patients and suggest that high fibrinogen plasma levels might be a risk marker for cardiovascular disease in diabetes because it is an expression of an existing thrombophilia.