Estimated insulin sensitivity, cardiovascular risk, and hepatic steatosis after 12 years from the onset of T1D.

AIM: To test the hypothesis that intensive insulin treatment and optimal glycaemic control are not fully protective against reduction of insulin sensitivity in children with type 1 diabetes. MATERIAL AND METHODS: Cohort study of 78 normal-weight patients with prepubertal onset (T0 ) and follow-up waves at 1 (T1 ), 5 (T5 ), 10 (T10 ), and 12 (T12 ) years; matched for age and sex to 30 controls at T12 . Estimated insulin sensitivity (eIS) by three formulae; ultrasound evaluation of para and perirenal fat thickness; hepatic steatosis (HS); carotid intima media thickness (cIMT) at T12 . RESULTS: At T12, the 36 patients (46%) who had constantly or prevalently haemoglobin A1c (HbA1c) < 58 mmol/l during follow-up showed better eIS indexes (p = 0.049 to <0.0001); lipid profile (p = 0.042 to <0.0001), reduced fat mass (p = 0.012) and required lower insulin dose (p = 0.032) than the 42 patients (54%) with HbA1c ≥ 58 at T12. Patients (N = 25) with eISEDC  < 8.77 mg kg-1  min-1 showed higher cIMT (p < 0.0001). HS was found in 6 patients (∼8%). In patients and normal-weight controls, fat mass (p = 0.03), age (p = 0.03), cIMT (p = 0.05) predicted HS; eIS indexes (p from 0.04 to <0.0001) predicted cIMT. Body mass index, perirenal fat, fat mass, and triglycerides to high density lipoprotein cholesterol ratio were associated with eIS indexes (p from 0.03 to <0.0001). CONCLUSIONS: Young T1D patients have reduced insulin sensitivity and higher cIMT. Adiposity, glucose, and lipid control over follow-up are likely to influence both. Enhanced adiposity seems of paramount relevance for the onset of HS in T1D patients alike in healthy youths.

Seroreactivity against Specific L5P Antigen from Mycobacterium avium subsp. paratuberculosis in Children at Risk for T1D.

AIMS/HYPOTHESIS: Although numerous environmental agents have been investigated over the years as possible triggers of type 1 diabetes (T1D), its causes remain unclear. We have already demonstrated an increased prevalence of antibodies against peptides derived from Mycobacterium avuim subsp. paratuberculosis (MAP) homologous to human zinc transporter 8 protein (ZnT8) and proinsulin in Italian subjects at risk for or affected by T1D. In this study, we compared titers of the previously detected antibodies with seroreactivity to MAP lipopentapetide (L5P) that recently emerged as a strong immunogenic component able to specifically distinguish MAP from other mycobacteria. METHODS: Plasma of 32 children and youth at risk for T1D including follow-up samples and 42 age-matched healthy controls (HC) recruited at the Tor Vergata University Hospital in Rome was analyzed by indirect ELISA for the presence of antibodies against MAP-derived epitopes MAP3865c133-141, MAP3865c125-133, MAP2404c70-85 and MAP1,4αgbp157-173 along with their ZnT8 and proinsulin homologs. The data were analyzed through two-tailed Mann-Whitney U test and relation between variables was determined by principal component analysis. RESULTS: Responses to L5P were not detectable in subjects whose initial seroreactivity to MAP peptides and their human homologs was lost in follow-up samples, whereas anti-L5P antibodies appeared constantly in individuals with a stable immunity against MAP antigens. The overall coincidence in positivity to L5P and the four MAP epitopes both in children at risk for T1D and HC exceeded 90%. CONCLUSIONS: MAP-derived homologs may cross-react with ZnT8 and proinsulin peptides inducing immune responses at a young age in subjects predisposed for T1D. Thus, L5P may have a diagnostic value to immediately indicate the presence of anti-MAP seroreactivity when evaluation of a more complex antibody status is not required. Almost complete coincidence in responses to both types of antigens lends support to the involvement of MAP in T1D.

Type 1 Diabetes at-risk children highly recognize Mycobacterium avium subspecies paratuberculosis epitopes homologous to human Znt8 and Proinsulin.

Mycobacterium avium subspecies paratuberculosis (MAP) has been previously associated to T1D as a putative environmental agent triggering or accelerating the disease in Sardinian and Italian populations. Our aim was to investigate the role of MAP in T1D development by evaluating levels of antibodies directed against MAP epitopes and their human homologs corresponding to ZnT8 and proinsulin (PI) in 54 T1D at-risk children from mainland Italy and 42 healthy controls (HCs). A higher prevalence was detected for MAP/ZnT8 pairs (62,96% T1D vs. 7,14% HCs; p < 0.0001) compared to MAP/PI epitopes (22,22% T1D vs. 9,52% HCs) and decreasing trends were observed upon time-point analyses for most peptides. Similarly, classical ZnT8 Abs and GADA decreased in a time-dependent manner, whereas IAA titers increased by 12%. Responses in 0-9 year-old children were stronger than in 10-18 age group (75% vs. 69,1%; p < 0.04). Younger age, female sex and concomitant autoimmune disorders contributed to a stronger seroreactivity suggesting a possible implication of MAP in multiple autoimmune syndrome. Cross-reactivity of the homologous epitopes was reflected by a high correlation coefficient (r(2) > 0.8) and a pairwise overlap of positivity (>83% for MAP/ZnT8).

Proinsulin and MAP3865c homologous epitopes are a target of antibody response in new-onset type 1 diabetes children from continental Italy.

Mycobacterium avium subspecies paratuberculosis (MAP) asymptomatic infection is speculated to play a role in type 1 diabetes (T1D) among Sardinian subjects. Data obtained analyzing a pediatric population from mainland Italy lends support to the hypothesis, which envisions MAP as an environmental factor at play in T1D pathogenesis. Aiming to investigate the likelihood of cross-recognition between linear determinants shared by self (proinsulin) and non-self (MAP) proteins, 59 children with new onset T1D and 60 healthy controls (HCs) from continental Italy were enrolled in the study. Serum samples were subjected to indirect enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies (Abs) toward four homologues MAP/proinsulin epitopes. The rate of MAP infection (42.4% in T1D children and 5% in HCs; p < 0.0001) was estimated searching for Abs against MAP specific protein MptD. The homologous MAP2404c70-85 and proinsulin (PI)46-61 peptides were recognized by 42.4 and 39% of new-onset T1D children and only in 5% of HCs (AUC = 0.76, AUC = 0.7, p < 0.0001); whereas the prevalence of Abs against MAP 1,4-α-gbp157-173 and PI64-80 peptides was 45.7 and 49.1% in new-onset T1D children, respectively, compared with 3.3% of HCs (AUC = 0.74 and p < 0.0001 in both). Pre-incubation of MAP Ab-positive sera with proinsulin peptides was able to block the binding to the correspondent MAP epitopes, thus showing that Abs against these homologous peptides are cross-reactive. MAP/Proinsulin Ab mediated cross-recognition, most likely via molecular mimicry, maybe a factor in accelerating and/or initiating T1D in MAP-infected children. Indeed, it is known that anti-proinsulin and anti-Insulin autoantibodies are the earliest to appear.

Study of factors influencing susceptibility and age at onset of type 1 diabetes: A review of data from Continental Italy and Sardinia.

AIM: To investigate the role of protein tyrosin phosphatase 22 (PTPN22), maternal age at conception and sex on susceptibility and age at onset of type 1 diabetes (T1D) in Continental Italy and Sardinian populations. METHODS: Three hundred seventy six subjects admitted consecutively to the hospital for T1D and 1032 healthy subjects as controls were studied in Continental Italy and 284 subjects admitted consecutively to the hospital for T1D and 5460 healthy newborns were studied in Sardinia. PTPN22 genotype was determined by DNA analysis. Maternal age at conception and age at onset of disease were obtained from clinical records. χ(2) test of independence, student t test for differences between means and odds ratio analysis were carried out by SPSS programs. Three way contingency table analysis was carried out according to Sokal and Rohlf. RESULTS: The pattern of association between PTPN22 and T1D is similar in Continental Italy and Sardinia: the proportion of *T allele carriers is 13.6% in T1D vs 6.7% in controls in Continental Italy while in Sardinia is 7.3% in T1D vs 4.4% in controls. The association between T1D and maternal age at conception is much stronger in Sardinia than in Italy: the proportion of newborn from mother aging more than 32 years is 89.3% in T1D vs 32.7% in consecutive newborn in Sardinia (P < 10(-6)) while in Continental Italy is 32.2% in T1D vs 19.1% in consecutive newborns (P = 0.005). This points to an important role of ethnicity. A slight prevalence of T1D males on T1D females is observed both in Continental Italy and Sardinia. PTPN22 genotype does not exert significant effect on the age at onset neither in Continental Italy nor and Sardinia. Maternal age does not influence significantly age at onset in Italy (8.2 years in T1D infants from mothers aging 32 years or less vs 7.89 years in T1D infants from mothers aging more than 32 years: P = 0.824) while in Sardinia a border line effect is observed (5.75 years in T1D infants from mothers aging 32 years or less vs 7.54 years in T1D infants from mothers aging more than 32 years: P = 0.062). No effect of sex on age at onset is observed in Continental Italy while in Sardinia female show a lower age at onset of T1D as compared to males (8.07 years in males vs 6.3 years in females: P = 0.002). CONCLUSION: The present data confirm the importance of ethnicity on susceptibility and on the age at onset of T1D.

De novo 13q13.3-21.31 deletion involving RB1 gene in a patient with hemangioendothelioma of the liver.

Interstitial deletions of the long arm of chromosome 13 (13q) are related with variable phenotypes, according to the size and the location of the deleted region. The main clinical features are moderate/severe mental and growth retardation, cranio-facial dysmorphism, variable congenital defects and increased susceptibility to tumors. Here we report a 3-year-old girl carrying a de novo 13q13.3-21.32 interstitial deletion. She showed developmental delay, growth retardation and mild dysmorphism including curly hair, high forehead, short nose, thin upper lip and long philtrum. An abnormal mass was surgically removed from her liver resulting in a hemangioendothelioma. Array analysis allowed us to define a deleted region of about 27.87 Mb, which includes the RB1 gene. This is the first report of a 13q deletion associated with infantile hemangioendothelioma of the liver.

A variable degree of autoimmunity in the pedigree of a patient with type 1 diabetes homozygous for the PTPN22 1858T variant.

We investigated whether the PTPN22 C1858T polymorphism is associated with the autoimmune conditions present in the family of a child affected by type 1 diabetes (T1D) carrying the TT genotype (index patient) and the potential immunological effect of the variant. We found that nine family members carried the CT genotype and five suffered from autoimmunity. Interestingly, anti-ZnT8 antibodies were detected in T1D patients and in three healthy relatives. In the TT patient, we showed diminished T-cell proliferation and reduced interleukin-2 (IL-2) and interferon-gamma (IFN-γ) production. A marked reduction of IL-2 was also observed for all CT relatives with autoimmunity and a lack of IFN-γ production was observed for the younger brother of the index patient, heterozygous for the polymorphism. In this family, the C1858T variant might confer a high risk of autoimmunity. Moreover, our data confirm that impaired IL-2 production upon T-cell receptor stimulation is associated with autoimmunity in the carriers of the polymorphism. This study might prompt to extend the panel of risk markers in relatives of subjects affected by T1D.

Autoimmune-associated PTPN22 R620W variation reduces phosphorylation of lymphoid phosphatase on an inhibitory tyrosine residue.

A missense C1858T single nucleotide polymorphism in the PTPN22 gene recently emerged as a major risk factor for human autoimmunity. PTPN22 encodes the lymphoid tyrosine phosphatase (LYP), which forms a complex with the kinase Csk and is a critical negative regulator of signaling through the T cell receptor. The C1858T single nucleotide polymorphism results in the LYP-R620W variation within the LYP-Csk interaction motif. LYP-W620 exhibits a greatly reduced interaction with Csk and is a gain-of-function inhibitor of signaling. Here we show that LYP constitutively interacts with its substrate Lck in a Csk-dependent manner. T cell receptor-induced phosphorylation of LYP by Lck on an inhibitory tyrosine residue releases tonic inhibition of signaling by LYP. The R620W variation disrupts the interaction between Lck and LYP, leading to reduced phosphorylation of LYP, which ultimately contributes to gain-of-function inhibition of T cell signaling.

Type 1 diabetes: evidence of interaction between ACP1 and ADA1 gene polymorphisms.

BACKGROUND: ACP1 (acid phosphatase locus 1, a cytosolic low-molecular-weight phosphotyrosin phosphatase) and ADA1 (adenosine deaminase locus 1) are two polymorphic systems involved in immune reactions. Observed interactions at the biochemical and clinical levels between the two systems prompted this investigation of a possible interaction concerning susceptibility to type 1 diabetes. MATERIAL/METHODS: Two hundred eighty-seven children admitted consecutively to the hospital for type 1 diabetes and 727 healthy newborn infants were studied. All were from the Caucasian Italian population living in the central area of Italy. ACP1 and ADA1 genotypes were determined by DNA analysis. RESULTS: In the type 1 diabetics the distribution of ACP1 genotypes was dependent on the ADA1 genotypes, showing an excess of the low-activity *A/*A and *A/*B genotypes in the ADA1*2 carriers compared with the ADA1*1/*1 subjects (OR: 2.200, 95%CI: 1.133-4.298). Such an association was not present in the healthy newborn infants. CONCLUSIONS: This investigation based on the biological effects of ACP1 and ADA1 on the immune system and on the known biochemical interaction between the two systems showed a significant interaction between the two system concerning susceptibility to type 1 diabetes. The low-activity ACP1 genotypes *A/*A and *A/*B carrying the low-activity ADA1*2 allele were more common in type 1 diabetic than in healthy newborns (OR: 1.699 95%CI: 1.066-2.702).

[Evaluation and prevention of type II diabetes mellitus and cardiovascular diseases in obese children and adolescents: a public health intervention in a local health organisation in Rome (Italy)]. / Un intervento di sanità pubblica per la valutazione e la prevenzione del diabete di tipo 2 e delle malattie cardiovascolari in bambini e adolescenti obesi.

INTRODUCTION: Prevention of childhood obesity and of its complications is an increasingly important public health priority. During 2002-2003 a network of family paediatricians working in the territory of a local health organisation in Rome (Italy) was created, in order to evaluate the health status of obese children. A preferential diagnostic and therapeutic management workup procedure was then developed for these patients at the Paediatrics department of the "Policlinico Tor Vergata" (PTV) university teaching hospital in Rome (Italy). METHODS: Family paediatricians invited children aged 6-14 years with a body mass index (BMI) above the 95th percentile, to a clinical consultation at PTV where each child then underwent a clinical evaluation (including blood pressure measurement and evaluation of family history of cardiovascular disease and type 2 diabetes mellitus) and laboratory testing (including oral glucose tolerance testing-OGTT, measurement of cholesterol and trygliceride levels). The BMI z score and insulin resistance index (HOMA-IR) were also calculated and pubertal stage was assessed. RESULTS: Overall, 168 children, with a mean age of 11 years, were evaluated; 53% were males. The mean BMI z score was 2.43+/-0.45. Forty-four percent of children were found to be hypertensive and 28.3% had a positive family history for type 2 diabetes mellitus. Fifteen children (9%) were found to have Impaired Glucose Tolerance (IGT) while one child was frankly diabetic. Thirty-six children (23.4%) were diagnosed with a metabolic syndrome (MS). Systolic blood pressure was significantly correlated with BMI z score and with 2 hour glucose levels. Obese children with either hypertension or a family history of diabetes were significantly more likely to have glucose intolerance or metabolic syndrome (GI, OR= 4.7 ; MS, OR= 6.8) CONCLUSIONS: A high percentage of obese children and adolescents develop metabolic complications. The percentage of children with such complications is greater when other risk factors such as hypertension and family history of type 2 diabetes are present. Family paediatricians play a fundamental role in the prevention, evaluation and treatment of child obesity. This study underscores the importance of performing routine evaluations of BMI and blood pressure in children aged 6-14 years, eventually by extending well-child visits to this age group.

Idiopathic central diabetes insipidus is associated with abnormal blood supply to the posterior pituitary gland caused by vascular impairment of the inferior hypophyseal artery system.

Central diabetes insipidus (CDI) has been linked to vascular central nervous system damage, although the pathophysiology of the mechanism has never been perfectly understood. Indeed, the vascular system of human pituitary gland has rarely been the subject of rigorous investigation except at postmortem. Recently, studies of pituitary gland blood supply have been carried out by means of a time evaluation of pituitary gland enhancement with noninvasive dynamic magnetic resonance (MR) imaging after contrast medium injection. In the present study, we decided to investigate the status of posterior pituitary blood supply by evaluating vascular pituitary patterns in a group of 19 patients with idiopathic CDI in whom previous standard MR imaging had failed to identify causal specific lesions. The control group was composed of 55 subjects with a median age of 12 yr (range, 4.2-17 yr) who had idiopathic isolated GH deficiency and normal pituitary morphology and 15 young adults (18-25 yr) who had normal pituitary gland and no endocrine dysfunction. Nineteen patients (12 females and seven males), ranging in age at the time of diagnosis of CDI from 0.5-14.9 yr (median, 5 yr), were examined with dynamic MR imaging between 1990 and 1997 at a median age of 14.1 yr (range, 5.0-26.3 yr). CDI was diagnosed according to clinical findings of polyuria and polydipsia, water deprivation test, and desmopressin acetate therapeutic trial. All of the patients had permanent CDI and were being treated with satisfactory results with desmopressin, two to three times daily, either intranasally or orally. The previous MR imaging findings of the 19 CDI patients had shown the absence of posterior pituitary hyperintensity, normal pituitary stalk, and normal anterior pituitary size. Enhancement of the straight sinus, representing a temporal reference point and occurring in normal subjects simultaneously to that of the posterior pituitary gland, was observed in all subjects after iv gadopentetate dimeglumine administration, with no substantial differences between patients and controls. However, the enhancement of the posterior pituitary lobe occurred simultaneously with the enhancement of the straight sinus in all of the controls but in only 14 of the 19 patients with CDI. In the remaining five patients, the enhancement of the straight sinus was not associated with the expected contrast enhancement of the posterior pituitary gland, suggesting abnormal blood supply to the posterior pituitary lobe. This is in keeping with vascular impairment of the inferior hypophyseal artery system and suggests that abnormal blood supply to the posterior pituitary gland is associated with what, until now, has been considered idiopathic CDI.