Paolo Ventura

Bone morphogenetic protein signaling is impaired in an Hfe knockout mouse model of hemochromatosis

BACKGROUND AND AIMS Mutations in HFE are the most common cause of the iron-overload disorder hereditary hemochromatosis. Levels of the main iron regulatory hormone, hepcidin, are inappropriately low in hereditary hemochromatosis mouse models and patients with HFE mutations, indicating that HFE regulates hepcidin. The bone morphogenetic protein 6 (BMP6)-SMAD signaling pathway is an important endogenous regulator of hepcidin expression. We investigated whether HFE is involved in BMP6-SMAD regulation of hepcidin expression. METHODS The BMP6-SMAD pathway was examined in Hfe knockout (KO) mice and in wild-type (WT) mice as controls. Mice were placed on diets of varying iron content. Hepcidin induction by BMP6 was examined in primary hepatocytes from Hfe KO mice; data were compared with those of WT mice. RESULTS Liver levels of Bmp6 messenger RNA (mRNA) were higher in Hfe KO mice; these were appropriate for the increased hepatic levels of iron in these mice, compared with WT mice. However, levels of hepatic phosphorylated Smad 1/5/8 protein (an intracellular mediator of Bmp6 signaling) and Id1 mRNA (a target gene of Bmp6) were inappropriately low for the body iron burden and Bmp6 mRNA levels in Hfe KO, compared with WT mice. BMP6 induction of hepcidin expression was reduced in Hfe KO hepatocytes compared with WT hepatocytes. CONCLUSIONS HFE is not involved in regulation of BMP6 by iron, but does regulate the downstream signals of BMP6 that are triggered by iron.

Serum and liver iron differently regulate the bone morphogenetic protein 6 (BMP6)-SMAD signaling pathway in mice

The bone morphogenetic protein 6 (BMP6)‐SMAD signaling pathway is a central regulator of hepcidin expression and systemic iron balance. However, the molecular mechanisms by which iron is sensed to regulate BMP6‐SMAD signaling and hepcidin expression are unknown. Here we examined the effects of circulating and tissue iron on Bmp6‐Smad pathway activation and hepcidin expression in vivo after acute and chronic enteral iron administration in mice. We demonstrated that both transferrin saturation and liver iron content independently influence hepcidin expression. Although liver iron content is independently positively correlated with hepatic Bmp6 messenger RNA (mRNA) expression and overall activation of the Smad1/5/8 signaling pathway, transferrin saturation activates the downstream Smad1/5/8 signaling cascade, but does not induce Bmp6 mRNA expression in the liver. Hepatic inhibitory Smad7 mRNA expression is increased by both acute and chronic iron administration and mirrors overall activation of the Smad1/5/8 signaling cascade. In contrast to the Smad pathway, the extracellular signal‐regulated kinase 1 and 2 (Erk1/2) mitogen‐activated protein kinase (Mapk) signaling pathway in the liver is not activated by acute or chronic iron administration in mice. Conclusion: Our data demonstrate that the hepatic Bmp6‐Smad signaling pathway is differentially activated by circulating and tissue iron to induce hepcidin expression, whereas the hepatic Erk1/2 signaling pathway is not activated by iron in vivo. (HEPATOLOGY 2011;)

Alendronate Reduces Bone Resorption in HIV-Associated Osteopenia/Osteoporosis

Abstract Purpose: To evaluate the effects of alendronate, vitamin D, and calcium supplementation on bone metabolism and bone mineral density (BMD) in both HIV-infected men and women treated with highly active antiretroviral therapy (HAART). Method: We performed a 52-week prospective, multicenter, randomized, open-label clinical trial. Eligible participants were on stable HAART and had BMD values at the femoral neck or lumbar spine that corresponded to a t score less than -1. Patients were randomized to receive alendronate 70 mg weekly or no alendronate; calcium 1000 mg daily and vitamin D 500 IU daily were provided to all study recipients. Primary endpoint of the study was the change in bone metabolism evaluated by N-telopeptide of type 1 collagen and bone-specific alkaline phosphatase; the secondary endpoint was BMD variation. Results: 18 patients were randomized to the alendronate and 23 to the no-alendronate group (controls). The alendronate-treatment group compared to controls had a significant decrease in serum N-telopeptides, 1914 ± 1433.4 vs. 3967 ± 1650.5 pM/L (p = .005) after 1 year. Lumbar spine BMD increased by 4% in the alendronate group (p = .004) vs. 3.7% (p = .062) in controls, compared to baseline values. Femoral neck BMD decreased by 0.5% in the alendronate group (p = .05) and by 3.5% in the control group (p = .04). No between-groups differences for BMD were found (Δ lumbar-BMD 0.0351 ± 0.0406 in cases and 0.0356 ± 0.073 in controls [p = .977], Δ femoral-BMD –0.085 ± 0.160 in cases and –0.100 ± 0.165 in controls [p = .795]). Conclusion: Alendronate plus vitamin D and calcium was effective in reducing bone resorption. Alendronate improved lumbar BMD and minimized femoral BMD decrease after 52 weeks compared to treatment with vitamin D and calcium alone in patients on HAART with osteopenia/osteoporosis.

Hepatocellular Carcinoma in HIV-Infected Patients: Check Early, Treat Hard

PURPOSE Hepatocellular carcinoma (HCC) is an increasing cause of mortality in HIV-infected patients in the highly active antiretroviral therapy (HAART) era. The aims of this study were to describe HCC tumor characteristics and different therapeutic approaches, to evaluate patient survival time from HCC diagnosis, and to identify clinical prognostic predictors in patients with and without HIV infection. PATIENTS AND METHODS A multicenter observational retrospective comparison of 104 HIV-infected patients and 484 uninfected patients was performed in four Italian centers. HCC was staged according to the Barcelona Clinic Liver Cancer (BCLC) criteria. RESULTS Tumor characteristics of patients with and without HIV were significantly different for age, Eastern Cooperative Oncology Group performance status (PS) score ≤1, and etiology of chronic liver disease. Despite the similar potentially curative option rate and better BCLC stage at diagnosis, the median survival time was significantly shorter in HIV(+) patients. HIV(+) patients were less frequently retreated at relapse. Independent predictors of survival were: BCLC stage, potentially effective HCC therapy, tumor dimension ≤3 cm, HCC diagnosis under a screening program, HCC recurrence, and portal vein thrombosis. Restricting the analysis to HIV(+) patients only, all positive prognostic factors were confirmed together with HAART exposure. CONCLUSION This study confirms a significantly shorter survival time in HIV(+) HCC patients. The less aggressive retreatment at recurrence approach does not balance the benefit of younger age and better BCLC stage and PS score of HIV(+) patients. Thus, considering the prognosis of HIV(+) HCC patients, effective screening techniques, programs, and specific management guidelines are urgently needed.

Hyperhomocysteinemia and Other Newly Recognized Inherited Coagulation Disorders (Factor V Leiden and Prothrombin Gene Mutation) in Patients with Idiopathic Cerebral Vein Thrombosis

Background: Idiopathic cerebral vein thrombosis (iCVT) represents approximately 30% of the cases of cerebral vein thrombosis (CVT). New, inherited – factor V Leiden (FVL) and prothrombin gene mutation (PTHRA20210) – and inherited/acquired – hyperhomocysteinemia (HHcy) – prothrombotic conditions have been detected recently. Methods: We assessed fasting plasma homocysteine (Hcy) levels and main Hcy determinants, FVL and PTHRA20210 in 30 patients with documented iCVT and 40 age- and sex-matched healthy subjects. Results: A strong and significant association of PTHRA20210 [30% (9/30) vs. 2.5% (1/40) iCVT vs. controls, respectively, p = 0.001; OR = 16.174, p = 0.002] and HHcy [13/30 (43.3%) vs. 4/40 (10%) iCVT vs. controls, respectively; p = 0.002, OR = 6.88, p = 0.002] with iCVT was found. Conclusions: PTHRA20210 and HHcy should be considered when screening for thrombophilia and should be assessed in patients with a family or personal history of CVT.

Peroxidation indices and total antioxidant capacity in plasma during hyperhomocysteinemia induced by methionine oral loading

Hyperhomocysteinemia is a risk factor for vascular disease, although its mechanism of action is not fully clear. Different experimental studies have suggested that homocysteine (Hcy) exerts a pro-oxidant effect in the presence of metal ions (Fe and Cu). To test for a similar effect in vivo, we studied plasma markers of lipid and protein oxidation during hyperhomocysteinemia induced by an oral methionine load. Twenty-nine subjects (aged 61 +/- 25 years; 17 women), 25 of whom underwent oral methionine (100 mg/kg) loading, were studied; in every case, we measured total plasma Hcy, malondialdehyde (MDA), conjugated dienes (DIE), and oxidized protein ([PTOX] carbonylic groups) in basal conditions and 4, 6, 8, and 24 hours after methionine loading. Four participants acted as controls. In every case, we also measured total plasma antioxidant capacity (ANTOX) in basal conditions and 8 hours after methionine loading. Eight hours after methionine loading, plasma Hcy increased from 17.6 +/- 11.4 to 54.3 +/- 31.6 nmol/mL, PTOX from 0.33 +/- 0.18 to 0.71 +/- 0.33 nmol/mg protein, DIE from 493 +/- 163 to 590 +/-202 optical density units, and MDA from 1.66 +/- 0.81 to 2.1 +/- 0.93 nmol/mL. There was a significant correlation (Spearmans r) between Hcy and both PTOX (r = .86, P = .01) and MDA (r = .47, P < .05) 8 hours after methionine loading. No significant modifications of the plasma parameters were found during the observation period in controls. ANTOX at 8 hours was significantly (paired ttest) reduced in probands (from 1.74 +/- 0.59 to 1.14 +/- 0.55 mmol/mL, P = .014); no significant difference was observed for plasma ANTOX in controls. Hyperhomocysteinemia due to oral methionine loading induced an increase in plasma oxidation markers. In the absence of hyperhomocysteinemia, no significant modifications were observed. These findings, together with the decrease in ANTOX and the corresponding increase in total plasma Hcy, are consistent with a pro-oxidant effect of acute hyperhomocysteinemia in vivo.

Hyperhomocysteinaemia in chronic liver diseases: role of disease stage, vitamin status and methylenetetrahydrofolate reductase genetics

Abstract: Background/Aims: The liver plays a key role in sulphur aminoacid metabolism hence, homocysteine metabolism may be impaired in chronic liver diseases. The aim of this study was to investigate, in patients affected by chronic liver diseases, (1) the prevalence of hyperhomocysteinaemia and (2) the role of its determinants such as the stage and the aetiology of disease, vitamin status, genetic documented alterations (methylenetetrahydrofolate reductase deficiency) and presence/absence of documented malignant evolution (hepatocellular carcinoma).

Serum Ferritin as a Predictor of Treatment Outcome in Patients With Chronic Hepatitis C

OBJECTIVES:Antiviral treatment in chronic hepatitis C (CHC) involves ribavirin, a hemolytic agent. We planned a prospective study to evaluate whether drug-induced iron perturbation is clinically relevant as it relates to therapeutic outcome.METHODS:Iron variables were sequentially assessed in 206 CHC patients undergoing antiviral therapy and were correlated with pretreatment iron status and histology, hemolysis, and therapeutic outcome.RESULTS:At week 1 of therapy, serum iron (SI), transferrin saturation (TS), and serum ferritin (SF) increased markedly in all patients. All iron parameters correlated with hemolysis up to week 4; this correlation was lost for SF at later time points. SF rise during treatment was inversely related to baseline SF and iron deposits in hepatic mesenchymal/Kupffer cells. Both baseline SF and mesenchymal iron significantly correlated with fibrosis at multivariate analysis (P=0.015 and 0.008, respectively). Interestingly, baseline SF, despite good specificity (89%), had low sensitivity in predicting siderosis (25%). During therapy, SI, TS, and hemolysis parameters did not correlate with sustained virological response (SVR), whereas SF rise became an independent predictor of therapeutic response: a 2.5-fold increase of SF at week 12 associated with higher likelihood of SVR (odds ratio 1.91, P=0.032). Accordingly, lack of mesenchymal iron deposits at the baseline biopsy correlated with SVR (odds ratio 3.02, P=0.043).CONCLUSIONS:In CHC, SF is a useful marker for assessing disease duration and progression before starting treatment and for predicting therapeutic response while on therapy. SF rise during antiviral therapy is largely independent of hemolysis and likely indicates activation of macrophages in response to antivirals.

Urinary and Plasma Homocysteine and Cysteine Levels during Prolonged Oral N-Acetylcysteine Therapy

Acute administration of N-acetylcysteine (NAC) may induce alterations in plasma and urinary levels of homocysteine (Hcy) and cysteine (Cys). We studied the effects of continuous oral NAC therapy on different Hcy and Cys plasma and urinary forms in 40 healthy subjects assigned to three groups (groups A: n = 13, no therapy; group B: n = 14, NAC 600 mg/day, and group C: n = 14, NAC 1,800 mg/day) for 1 month (T1). After a 1-month washout period without therapy (T2), all subjects were treated with oral NAC (1,800 mg/day) for 2 months and (T3 and T4) reassessed monthly for plasma and urinary thiols. The treated subjects showed a significant decrease in plasma total Hcy and a slight increase in total Cys levels; the alterations of different forms of plasma thiols suggested an NAC-induced increase in disulfide forms and an increase in urinary Hcy and Cys excretion as disulfide forms. The effects appeared to be dose dependent, being more marked in subjects treated with higher dosages. This approach may be important, as an association or alternative therapy in hyperhomocysteinemic conditions of poor responses to vitamins.

Duplex‐Doppler assessment of cirrhosis in patients with chronic compensated liver disease

Portal venous flow velocity (PFV) was measured with duplex‐Doppler equipment in 50 normal subjects and in 117 patients with suspected chronic liver disease who showed no evidence of decompensation such as ascites, hepatic encephalopathy, jaundice or oesophageal bleeding. All the patients underwent percutaneous liver biopsy which demonstrated non‐cirrhotic liver disease in 58 cases (CH‐patients: steatosis 8, persistent chronic hepatitis 8, active chronic hepatitis 42) and liver cirrhosis in the other 59 cases (LC‐patients).