Maria Gisella Cavallo

No effect of oral insulin on residual beta-cell function in recent-onset Type I diabetes (the IMDIAB VII)

Aims/hypothesis. Induction of tolerance to insulin is achievable in animal models of Type I (insulin-dependent) Diabetes mellitus by oral treatment with this hormone, which can lead to prevention of the disease. In the Diabetes Prevention Trial of Type I diabetes (DPT-1), oral insulin is given with the aim of preventing disease insurgence. We investigated whether if given at diagnosis of Type I diabetes in humans, oral insulin can still act as a tolerogen and therefore preserve residual beta-cell function, which is known to be substantial at diagnosis. Methods. A double-blind trial was carried out in patients (mean age ± SD: 14 ± 8 years) with recent-onset Type I diabetes to whom oral insulin (5 mg daily) or placebo was given for 12 months in addition to intensive subcutaneous insulin therapy. A total of 82 patients with clinical Type I diabetes ( < 4 weeks duration) were studied. Basal C peptide and glycated haemoglobin were measured and the insulin requirement monitored every 3 months up to 1 year. Insulin antibodies were also measured in 27 patients treated with oral insulin and in 18 patients receiving placebo at the beginning of the trial and after 3, 6 and 12 months of treatment. Results. The trial was completed by 80 patients. Overall and without distinction between age at diagnosis, at 3, 6, 9 and 12 months baseline mean C-peptide secretion in patients treated with oral insulin did not differ from that of those patients treated with placebo. In patients younger than 15 years a tendency for lower C-peptide values at 9 and 12 months was observed in the oral insulin group. Insulin requirement at 1 year was similar between the two groups as well as the percentage of glycated haemoglobin. Finally, IgG insulin antibodies were similar in the two groups at each time point. Conclusion/interpretation. The results of this study indicate that the addition of 5 mg of oral insulin does not modify the course of the disease in the first year after diagnosis and probably does not statistically affect the humoral immune response against insulin. [Diabetologia (2000) 43: 1000–1004]

Strong association between non alcoholic fatty liver disease (NAFLD) and low 25(OH) vitamin D levels in an adult population with normal serum liver enzymes

BackgroundHypovitaminosis D has been recently recognized as a worldwide epidemic. Since vitamin D exerts significant metabolic activities, comprising free fatty acids (FFA) flux regulation from the periphery to the liver, its deficiency may promote fat deposition into the hepatocytes. Aim of our study was to test the hypothesis of a direct association between hypovitaminosis D and the presence of NAFLD in subjects with various degree of insulin-resistance and related metabolic disorders.MethodsWe studied 262 consecutive subjects referred to the Diabetes and Metabolic Diseases clinics for metabolic evaluation. NAFLD (non-alcoholic fatty liver disease) was diagnosed by upper abdomen ultrasonography, metabolic syndrome was identified according to the Third Report of National Cholesterol Education Program/Adult Treatment Panel (NCEP/ATPIII) modified criteria. Insulin-resistance was evaluated by means of HOMA-IR. Fatty-Liver-Index, a recently identified correlate of NAFLD, was also estimated. Serum 25(OH)vitamin D was measured by colorimetric method.ResultsPatients with NAFLD (n = 162,61.8%) had reduced serum 25(OH) vitamin D levels compared to subjects without NAFLD (14.8 ± 9.2 vs 20.5 ± 9.7 ng/ml, p < 0.001, OR 0.95, IC 95% 0.92-0.98). The relationship between NAFLD and reduced 25(OH)vitamin D levels was independent from age, sex, triglycerides, high density lipoproteins (HDL) and glycaemia (p < 0.005) and Fatty Liver Index inversely correlated with low 25(OH) vitamin D regardless sex, age and HOMA-IR (p < 0.007).ConclusionsLow 25(OH)vitamin D levels are associated with the presence of NAFLD independently from metabolic syndrome, diabetes and insulin-resistance profile.

Liver vitamin D receptor, CYP2R1, and CYP27A1 expression: relationship with liver histology and vitamin D3 levels in patients with nonalcoholic steatohepatitis or hepatitis C virus

Evidence suggests an association between low serum 25‐hydroxy‐vitamin D3 [25(OH)D3] levels and the presence and prognosis of liver disease. Vitamin D receptor (VDR) has been widely detected in the liver, but its expression in the course of liver disease has never been investigated. We evaluated the hepatic expression of VDR along with that of vitamin D 25‐hydroxylases in patients with nonalcoholic steatohepatitis (NASH) or chronic hepatitis C (CHC) and its relationship with hepatic histological features and serum 25(OH)D3 levels. We evaluated 61 patients (25 NASH and 36 CHC) who had undergone liver biopsy for clinical purposes and 20 subjects without liver disease. Serum 25(OH)D3 was measured via colorimetric assay. Expression of VDR, CYP2R1, and CYP27A1 was evaluated via immunohistochemistry in hepatocytes, cholangiocytes, and liver inflammatory cells. Parenchymal and inflammatory cells from liver biopsies of patients with NASH and CHC expressed VDR, CYP2R1, and CYP27A1. In NASH patients, VDR expression on cholangiocytes was inversely correlated with steatosis severity (P < 0.02), lobular inflammation (P < 0.01), and nonalcoholic fatty liver disease score (P < 0.03). Moreover, expression of CYP2R1 in hepatocytes correlated strongly with VDR positivity on liver inflammatory cells. In CHC subjects, fibrosis stage was associated with low hepatic CYP27A1 expression, whereas portal inflammation was significantly higher in patients with VDR‐negative inflammatory cells (P < 0.009) and low VDR expression in hepatocytes (P < 0.03). Conclusion: VDR is widely expressed in the liver and inflammatory cells of chronic liver disease patients and its expression is negatively associated with the severity of liver histology in both NASH and CHC patients. These data suggest that vitamin D/VDR system may play a role in the progression of metabolic and viral chronic liver damage. (HEPATOLOGY 2012;56:2180–2187)

No protective effect of calcitriol on β-cell function in recent-onset type 1 diabetes the IMDIAB XIII trial.

OBJECTIVE We investigated whether supplementation of the active form of vitamin D (calcitriol) in recent-onset type 1 diabetes can protect β-cell function evaluated by C-peptide and improve glycemic control assessed by A1C and insulin requirement. RESEARCH DESIGN AND METHODS Thirty-four subjects (aged 11–35 years, median 18 years) with recent-onset type 1 diabetes and high basal C-peptide >0.25 nmol/l were randomized in a double-blind trial to 0.25 μg/day calcitriol or placebo and followed-up for 2 years. RESULTS At 6, 12, and 24 months follow-up, A1C and insulin requirement in the calcitriol group did not differ from the placebo group. C-peptide dropped significantly (P < 0.001) but similarly in both groups, with no significant differences at each time point. CONCLUSIONS At the doses used, calcitriol is ineffective in protecting β-cell function in subjects (including children) with recent-onset type 1 diabetes and high C-peptide at diagnosis.

Cytokines in sera from insulin-dependent diabetic patients at diagnosis.

Cytokines are known to play an important role in autoimmunity and have been suggested to be involved in the pathogenesis of insulin‐dependent diabetes (IDDM). In the present study we have measured IL‐1, IL‐2, IL‐4, IL‐6, interferon‐gamma(IFN‐γ)and tumour necrosis factor (TNF) (using both immunoassays and bioassays) in sera from 50 patients affected by IDDM at the time of clinical diagnosis and 51 age and sex matched controls. Detectable levels of IL‐I, IL‐2, IL‐6 and IFN‐μgK were found in the serum of a small percentage of subjects and were not significantly different between patients and controls. IL‐4 was detectable in a higher number of both patients and controls and circulating TNF‐α (> I U/ml) was found in a percentage of patients (24%) significantly higher than controls (P<0.01). Raised levels of TNF‐α were detectable using an immunoenzymatic assay whereas TNF bioactivity in these samples was negligible. We conclude that the presence of immunoreactive TNF‐α in the patients sera may reflect an increased localized production of this cytokine at pancreatic level. However, the measurement in serum of other cytokines does not add information on the role that they may play in the pathogenesis of IDDM.

Double blind trial of nicotinamide in recent-onset IDDM (the IMDIAB III study)

SummaryNicotinamide has been recently introduced, in addition to intensive insulin therapy for patients with recent-onset insulin-dependent diabetes mellitus (IDDM) to protect beta cells from end-stage destruction. However, available data are conflicting. A double blind trial in 56 newly-diagnosed IDDM patients receiving nicotinamide for 12 months at a dose of 25 mg/kg body weight or placebo was designed in order to determine whether this treatment could improve the integrated parameters of metabolic control (insulin dose, glycated haemoglobin and C-peptide secretion) in the year after diagnosis. In addition to nicotinamide or placebo, patients received three to four insulin injections daily to optimize blood glucose levels. Patients treated with nicotinamide or placebo received similar doses of insulin during follow-up and 1 year after diagnosis with comparable glycated haemoglobin levels (6.7±1.8 % nicotinamide vs 7.1±0.6 % placebo). Basal and glucagon stimulated C-peptide secretion detectable at diagnosis were similarly preserved in the course of 12 months follow-up both in nicotinamide and placebo treated patients. No adverse effects were observed in patients receiving nicotinamide. When age at diagnosis was taken into account, nicotinamide treated older patients ( > 15 years of age) showed significantly higher stimulated C-peptide secretion than placebo treated patients (p < 0.02). These results suggest that nicotinamide can preserve and improve stimulated beta-cell function only in patients diagnosed after puberty. We conclude that in these patients nicotinamide can be added to insulin at the time of disease diagnosis to maintain and possibly improve residual beta-cell function. However, further studies on patients diagnosed after puberty are needed to confirm whether nicotinamide can be considered an additional tool to insulin in early-onset IDDM.

The immune response to influenza vaccination in diabetic patients

SummaryThe immune response of diabetic patients to influenza vaccination was examined in 31 patients, 10 with Type 1 (insulin-dependent) diabetes and 21 with Type 2 (non-insulin-dependent diabetes), and in 19 normal subjects. Each received a single intramuscular injection of the 3 virus strains (A/Chile,A/Philippines,B/USSR) anti-influenza vaccine recommended by WHO. The antibody titre and the cell-mediated immune response to the 3 virus strains, as evaluated by the generation of activated lymphocytes and enumeration of B lymphocytes, were studied before and 18 h, 72 h and 1, 2, 3 and 6 weeks after vaccination. Overall, the humoral and cell-mediated immune responses were normal in both groups of patients. However, patients with Type 1 diabetes showed a statistically significant increase (p< 0.01) of antibody titre of the A/Chile and an increased percentage of B lymphocytes one week after vaccination compared to age-matched control subjects. Four out of 21 patients with Type 2 diabetes had no antibody response to all 3 virus strains. A significant reduction (p< 0.01) of the percentage of activated cells possessing receptors for interleukin-2 was observed 72 h after vaccination in patients with Type 2 diabetes compared to age-matched control subjects. None of the patients who received the vaccine developed influenza in the course of the following year. These results suggest that valid protection against the influenza virus can be obtained in patients with Type 1 and Type 2 diabetes.

3,5,3′-triiodothyronine (T3) is a survival factor for pancreatic β-cells undergoing apoptosis

3,5,3′‐triiodothyronine (T3) is essential for the growth and the regulation of metabolic functions, moreover, the growth‐stimulatory effect of T3 has largely been demonstrated and the pathways via which T3 promotes cell growth have been recently investigated. Type 1 diabetes (T1D) is due to the destruction of β‐cells, which occurs even through apoptosis. Aim of our study was to analyze whether T3 could have an antiapoptotic effect on cultured β‐cells undergoing apoptosis. We have demonstrated that T3 promotes cell proliferation in islet β‐cell lines (rRINm5F and hCM) provoking an increment in cell number (up to 55%: rRINm5F and 45%: hCM), cell viability, and BrdU incorporation, and regulating the cell cycle‐related molecules (cyc A, D1, E, and p27kip1). T3 inhibited the apoptotic process induced by streptozocin, S‐Nitroso‐N‐Acetylpenicylamine (SNAP), and H2O2 via regulation of the pro‐ and anti‐apoptotic factors Bcl‐2, Bcl‐XL, Bad, Bax, and Caspase 3. The T3 protective effect was PI‐3 K‐, but not MAPK‐ or PKA‐mediated, involving pAktThr308. Thus, T3 could be considered a survival factor protecting islet β‐cells from apoptosis. J. Cell. Physiol. 206: 309–321, 2006.

Cytokines and autoimmunity

Although the immunopathology of most autoimmune diseases has been well defined, the mechanisms responsible for the breakdown of self‐tolerance and which lead to the development of systematic and organ‐specific autoaggression are still unclear. Evidence has accumulated which supports a role for a disregulated production of cytokines by leucocytes and possibly other cells in the pathogenesis of some autoimmune diseases. However, due to the complexity and heterogeneity of cytokine effects in the regulation of the immune response, it is difficult to determine whether abnormalities in the patterns of cytokine production are primary or secondary to the pathological process. Confusion is also caused by the fact that the biological activities of cytokines are multiple and often overlapping, and consequently it is difficult to focus on a unique effect of any one cytokine. Characterization of the potential and actual involvement of cytokines is important not only for a better understanding of the pathogenesis of autoimmune conditions, but particularly because of the implications for the development of immunotherapeutic strategies for the prevention and treatment of the diseases.

A multi-centre randomized trial of two different doses of nicotinamide in patients with recent-onset Type 1 diabetes (the IMDIAB VI)

Intensive insulin therapy is the gold standard by which Type 1 diabetes is treated. In addition to this therapy, administration of nicotinamide (NA) can be beneficial. This concept is reinforced by the results of a recent meta‐analysis of the use of NA in patients with recent‐onset Type 1 diabetes.