Association between intestinal permeability and faecal microbiota composition in Italian children with beta cell autoimmunity at risk for type 1 diabetes.

BACKGROUND: Pancreatic organ-specific autoimmunity in subjects at risk for type 1 diabetes (T1D) is associated with increased intestinal permeability and an aberrant gut microbiota, but these factors have not yet been simultaneously investigated in the same subjects. Thus, the aim of this study was to assess both intestinal permeability and gut microbiota composition in an Italian sample of children at risk for T1D. METHODS: Ten Italian children with beta cell autoimmunity at risk for T1D and 10 healthy children were involved in a case-control study. The lactulose/mannitol test was used to assess intestinal permeability. Analysis of microbiota composition was performed using polymerase chain reaction followed by denaturing gradient gel electrophoresis, based on the 16S rRNA gene. RESULTS: Intestinal permeability was significantly higher in children at risk for T1D than in healthy controls. Moreover, the gut microbiota of the former differed from that of the latter group: Three microorganisms were detected - Dialister invisus, Gemella sanguinis and Bifidobacterium longum - in association with the pre-pathologic state. CONCLUSIONS: The results of this study validated the hypothesis that increased intestinal permeability together with differences in microbiota composition are contemporaneously associated with the pre-pathological condition of T1D in a sample of Italian children. Further studies are necessary to confirm the microbial markers identified in this sample of children as well as to clarify the involvement of microbiota modifications in the mechanisms leading to increased permeability and the autoimmune mechanisms that promote diabetes onset. Copyright © 2016 John Wiley & Sons, Ltd.

IGF1 and PPARG polymorphisms are associated with reduced estimated glomerular filtration rate in a cohort of children and adolescents with type 1 diabetes.

INTRODUCTION: Several genetic loci have been associated with diabetic nephropathy; however, the underlying genetic mechanisms are still poorly understood, with no robust candidate genes identified yet. AIM: We aimed to determine whether two polymorphisms, previously associated with renal decline, influence kidney impairment evaluating their association with markers of renal function in a pediatric population with type 1 diabetes (T1D). MATERIAL AND METHODS: Renal function was evaluated by glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR) in a cohort of pediatric subjects with T1D (n = 278). Risk factors for diabetes complications (diabetes duration, blood pressure, HbA1c) were assessed. The IGF1 rs35767 and PPARG rs1801282 SNPs were genotyped by TaqMan RT-PCR system. An additive genetic interaction was calculated. Association analysis between markers of renal function and both SNPs or their additive interaction were performed. RESULTS: Both SNPs showed a significant association with eGFR: the A allele of rs35767 or the C allele of rs1801282 were associated to reduced eGFR compared to G alleles. Multivariate regression analysis adjusted for age, sex, z-BMI, T1D duration, blood pressure and Hba1c values showed that the additive genetic interaction was independently associated with lower eGFR (ß = -3.59 [-6.52 to -0.66], p = 0.017). No associations were detected between SNPs, their additive interaction and ACR. CONCLUSIONS: These results provide new insight into the genetic predisposition to renal dysfunction, showing that two polymorphisms in IGF1 and PPARG genes can lead to a reduction in renal filtration rate leading these patients to be exposed to a higher risk of early renal complications.

Diet, physical, and biochemical characteristics of children and adolescents with type 1 diabetes: relationship between dietary fat and glucose control.

BACKGROUND: Nutritional habits may significantly influence glycemic control and cardiovascular risk factors in youth with type 1 diabetes (T1D). AIMS: To assess dietary intake, cardiovascular risk factors, and the association between diet composition and glycemic control in Italian youth with T1D. METHODS: Subjects included 114 youth aged 6-16 yr with T1D receiving a routine treatment program with nutrition counseling and 448 controls. Cross-sectional measures included dietary intake, anthropometry, blood pressure, lipid profile, and, in children with diabetes, HbA1c. RESULTS: In prepubertal children, BMI, subcutaneous skinfolds, the prevalence of overweight/obesity, and LDL cholesterol (LDL-CH) were significantly lower in patients than in controls, whereas HDL cholesterol (HDL-CH) was higher. Pubertal boys with T1D did not differ significantly from controls in either anthropometry or lipid profile. Pubertal girls with T1D had a higher BMI and higher triceps skinfolds than controls but not significantly different prevalence of overweight/obesity or lipid profile. Compared to controls, participants with T1D had a lower intake of lipids and simple carbohydrates, a higher ratio of unsaturated/saturated fats and fibre, and a dietary intake closer to the National Reference Dietary Intakes (RDIs). The odds of having an HbA1c higher than 7.5, adjusted for BMI, lipid, and fibre intake, increases by 53% for every 1% increase of energy intake from saturated fat in the diet and by 30% for every year of duration of diabetes. CONCLUSIONS: Youth with T1D having regular nutritional counseling had a diet closer to RDIs than controls and not different cardiovascular risk factors. High saturated fatty acid intake was associated with poor blood glucose control.

Monogenic Diabetes Accounts for 6.3% of Cases Referred to 15 Italian Pediatric Diabetes Centers During 2007 to 2012.

Context: An etiologic diagnosis of diabetes can affect the therapeutic strategy and prognosis of chronic complications. Objective: The aim of the present study was to establish the relative percentage of different diabetes subtypes in patients attending Italian pediatric diabetes centers and the influence of an etiologic diagnosis on therapy. Design, Setting, and Patients: This was a retrospective study. The clinical records of 3781 consecutive patients (age, 0 to 18 years) referred to 15 pediatric diabetes clinics with a diagnosis of diabetes or impaired fasting glucose from January 1, 2007 to December 31, 2012 were examined. The clinical characteristics of the patients at their first referral to the centers, type 1 diabetes-related autoantibodies, molecular genetics records, and C-peptide measurements, if requested for the etiologic diagnosis, were acquired. Main Outcome Measures: The primary outcome was to assess the percentage of each diabetes subtype in our sample. Results: Type 1 diabetes represented the main cause (92.4%) of diabetes in this group of patients, followed by monogenic diabetes, which accounted for 6.3% of cases [maturity onset diabetes of the young (MODY), 5.5%; neonatal diabetes mellitus, 0.6%, genetic syndromes, 0.2%]. A genetic diagnosis prompted the transfer from insulin to sulphonylureas in 12 patients bearing mutations in the HNF1A or KCNJ11 genes. Type 2 diabetes was diagnosed in 1% of the patients. Conclusions: Monogenic diabetes is highly prevalent in patients referred to Italian pediatric diabetes centers. A genetic diagnosis guided the therapeutic decisions, allowed the formulation of a prognosis regarding chronic diabetic complications for a relevant number of patients (i.e.,GCK/MODY), and helped to provide genetic counseling.

Normal or defective immune response to Hepatitis B vaccine in patients with diabetes and celiac disease.

A defective production of protective levels of antibodies to Hepatitis B (HB) vaccine is reported to occur in 4-10% of healthy subjects and a correlation with the presence of specific human leukocyte antigen (HLA) molecules, including DQ2, which also confers genetic predisposition to celiac disease (CD) and type I diabetes mellitus (T1DM), has been suggested.   The aim of this study was to analyze the serological response to HB vaccine and measles-containing vaccines in 69 diabetic patients (T1DM), 42 patients with celiac disease (CD) and 79 healthy control subjects (CT). The median interval between the third dose of HB vaccine and serum collection was 6.8, 3.5, and 4.7 years for T1DM, CD and CT groups, respectively. 50/69 (72%) T1DM patients, 32/42 (76%) CD patients and 61/79 (77%) CT subjects showed protective anti-HBs antibodies after vaccination, with no statistically significant difference. On the contrary, a lower statistically significant difference was found in the mean HBsAb level of T1DM subjects when compared with the other two groups. No correlation between HLA DQ2 expression in T1DM and vaccine response was detected. The comparison of serological response to measles after vaccination also showed no statistically significant differences in the three groups. Contrasting results between these data and those reported in the literature might be due to differences in the time intervals between vaccination and testing. Prospective studies in pathological and healthy groups with the same age at HBV vaccination and with the same time interval for blood sample collection to determine antibody titers are necessary in order to provide more conclusive data.

Epidemiology of type 1 diabetes mellitus in the pediatric population in Veneto Region, Italy.

We assessed the prevalence and incidence of type 1 diabetes mellitus (T1DM) in Veneto Region in Italy. The average prevalence and incidence rates were 1.26/1000 subjects and 16.5/100,000 person-years, respectively. This study shows that the Veneto Region is an area with intermediate-high risk of T1DM.

Diabetic ketoacidosis at diagnosis: role of family history and class II HLA genotypes.

OBJECTIVE: To explore the relationship between family history of diabetes and frequency of diabetic ketoacidosis (DKA) at diagnosis and to analyze the possible association between HLA genotypes and DKA. DESIGN AND METHODS: We recruited 510 children and adolescents aged <17 years with type 1 diabetes (T1D) and collected information on first-degree relative (FDR) history of T1D. DKA and severe DKA were defined as blood pH <7.30 and <7.10 at diabetes onset respectively. Risk categories for developing T1D were determined according to various HLA DQA1-DQB1 haplotype combination genotypes. RESULTS: The frequency of DKA and severe DKA at diagnosis was 34.7 and 7.2% respectively. DKA was more frequent in younger patients (<2 years (60.0%; P<0.001)) and occurred less in children with at least one FDR affected by T1D (13.0 vs 37.4%, P<0.001). The logistic regression showed that age at diagnosis (<2 years) and increased HLA-associated risk genotypes were independent predictors of DKA (P<0.01, odds ratio (OR)=1.068 (95% confidence interval (CI) 1.021-1.117); P<0.05, OR=1.606 (95% CI 1.034-2.475)). Introducing the presence of T1D in at least one FDR in the logistic model, a significant association between DKA and age at diagnosis (<2 years; P<0.01, OR=1.072 (95% CI 1.024-1.123)) and absence of FDRs with T1D (P=0.001, OR=4.287 (95% CI 1.770-10.383)) was found, but no more with increased HLA-associated risk genotype (P=0.06, OR=1.550 (95% CI 0.992-2.423)). CONCLUSIONS: HLA-associated high-risk genotypes are associated with a high chance of presenting DKA at diabetes onset. However, having at least one FDR with T1D reduced the risk of DKA regardless of HLA genotype.

A subset of anti-rotavirus antibodies directed against the viral protein VP7 predicts the onset of celiac disease and induces typical features of the disease in the intestinal epithelial cell line T84.

Celiac disease (CD) is an autoimmune disorder of the small intestine triggered by environmental factors in genetically predisposed individuals. A strong association between type 1 diabetes (T1DM) and CD has been reported. We have previously shown that rotavirus infection may be involved in the pathogenesis of CD through a mechanism of molecular mimicry. Indeed, we identified a subset of anti-transglutaminase IgA antibodies that recognize the rotavirus viral protein VP7. In this study, we aimed at evaluating whether such antibodies may predict the onset of CD in children affected by T1DM. Moreover, to further analyze the link between rotavirus infection and pathogenesis of CD, we analyzed the effect of anti-rotavirus VP7 antibodies on T84 intestinal epithelial cells using the gene-array technique, complemented by the analysis of molecules secreted in the supernatant of stimulated cells. We found that anti-rotavirus VP7 antibodies are present in the vast majority (81%) of T1DM-CD tested sera, but are detectable also in a fraction (27%) of T1DM children without CD. Moreover, we found that anti-rotavirus VP7 antibodies are present before the CD onset, preceding the detection of anti-tTG and anti-endomysium antibodies. The gene-array analysis showed that purified anti-rotavirus VP7 antibodies modulate genes that are involved in apoptosis, inflammation, and alteration of the epithelial barrier integrity in intestinal epithelial cells, all typical features of CD. Taken together, these new data further support the involvement of rotavirus infection in the pathogenesis of CD and suggest a predictive role of anti-rotavirus VP7 antibodies.

Nutritional education and carbohydrate counting in children with type 1 diabetes treated with continuous subcutaneous insulin infusion: the effects on dietary habits, body composition and glycometabolic control.

Carbohydrate counting (CHC) in combination with nutritional education has been used to optimize the insulin dose in patients with type 1 diabetes (T1D). The aim of this study was to test the impact of CHC and nutritional education on changes in dietary habits, body composition and body fat distribution in children with T1D treated with insulin pumps (CSII). Twenty-five children with T1D and CSII were recruited and valuated at baseline and after 18 months of follow-up. They were trained in CHC and following standard nutrition education program (based on American Diabetes Association and International Society of Pediatric and Adolescent Diabetes guidelines); clinical, biochemical and nutritional variables were measured. In the total population, body composition, body fat distribution and biochemical variables did not change, at follow-up; HbA1c was significantly reduced (8.50 ± 0.77 vs 7.92 ± 0.74 %; p < 0.001) without changing insulin/kg/day requirement. In the sub-group of patients with a significant HbA1c reduction (ΔHbA1c ≥ 0.5 %, n = 12), the carbohydrate (CHO) intake was significantly higher at follow-up (53.0 ± 4.0 vs 57.6 ± 2.5 %; p < 0.01); on the contrary, fat (31.3 ± 3.6 vs 28.5 ± 1.6 %; p < 0.05) and protein intake (15.4 ± 1.8 vs 13.3 ± 1.6 %; p < 0.01) significantly decreased. Patients without a significant HbA1c reduction did not show any difference. CHC, in combination with nutritional education, does not affect dietary habits, body composition and body fat distribution in children with T1D treated with CSII. Moreover, the sub-group of subjects showing a significant improvement in glycometabolic control reported an increase in CHO intake and a reduction in fat and protein intake.

A novel synonymous substitution in the GCK gene causes aberrant splicing in an Italian patient with GCK-MODY phenotype.

GCK gene analysis in an Italian MODY patient revealed a novel synonymous substitution in exon 4 (c.459T>G; p.Pro153Pro) resulting in an aberrant transcript lacking the last eight codons of the same exon. Our findings emphazise the importance of not underestimating synonymous variations when screening for disease-causing mutations.