Long-term complications of type 1 diabetes: what do we know and what do we need to understand?

Long-term complications of type 1 diabetes (T1D) include microvascular complications and macrovascular disease. Despite the important advances in the treatment of T1D of the last decades, these complications still represent the leading cause of morbidity and mortality in patients with T1D. Extensive evidence indicates that structural and functional alterations of the kidney, retina, nerves and large arteries occur already in the first years after the onset of diabetes. We performed a comprehensive review of the available evidence on screening, diagnosis, prevention and treatment of vascular complications of T1D. In particular, we focused on three major challenges related to long-term complications of T1D: 1) finding of new biomarkers and diagnostic methods able to identify early signs of complications; 2) identifying specific risk factors for the development of these complications; 3) identifying and implementing new therapeutic strategies able to prevent the development and progression of vascular complications.

Cardiovascular risk factors in children and adolescents with type 1 diabetes in Italy: a multicentric observational study.

AIMS: To assess the prevalence of cardiovascular risk factors (CVRFs) and to identify the variables associated with CVRFs in a cohort of children and adolescents with Type 1 Diabetes. METHODS: 2021 subjects, 2-18 year-old, were recruited in 17 Italian Pediatric Diabetes Centers. Anthropometric, blood pressure, biochemical (HbA1c, lipid profile, ACR), insulin therapy, physical activity level, smoking and family socio-economic status data were collected. CVRFs prevalence and their distribution were analyzed according to age and binary logistic regression was performed with positivity for at least one major CVRF (BMI-SDS > +2SD, blood pressure > 90th percentile, LDL cholesterol>100 mg/dL) as dependent variable and age, duration of illness, gender, HbA1c and physical activity, as independent variables. RESULTS: The prevalence of CVFRs not at the recommended target was respectively: 32.5% one CVRF, 6.7% two CVRFs and 0.6% three CVRFs, with no significant differences across the 3 age groups (2-10, 10-15, 15-18 years). In the total sample, HbA1c and inadequate physical activity were associated with a higher probability of having at least one major CVRF. This probability was associated with physical activity in the 2-10-year-old group, with physical activity and HbA1c in the 10-15-year-old group and with HbA1c only in subjects older than 15 years. CONCLUSIONS: More than 30% of subjects had at least a major CVRF. Early detection of CVRFs may be useful to enforce the therapeutic intervention in this subgroup, in order to reduce the risk to develop cardiovascular complications.

Expression of glucose transporters in duodenal mucosa of patients with type 1 diabetes.

AIMS: A higher SGLT1 and GLUT2 gene expression was shown in the intestine of subjects with type 2 diabetes, while no data have been reported in type 1 diabetes (T1D). The purpose of our study was to evaluate the expression of glucose transporters in duodenal mucosa of subjects with T1D, compared to healthy controls (CTRL) and to patients with celiac disease (CD), as gut inflammatory disease control group. MATERIALS AND METHODS: Gene expression of GLUT1, GLUT2, SGLT1 and SGLT2 was quantified on duodenal mucosa biopsies of subjects with T1D (n = 19), CD (n = 16), T1D and CD (n = 6) and CTRL (n = 12), recruited at San Raffaele Hospital (Milan, Italy), between 2009 and 2018. SGLT2 expression was further evaluated by immunohistochemical and immunofluorescence staining. RESULTS: The expression of all four glucose transporters was detected in duodenal mucosa of all groups. A reduced GLUT2, SGLT1 and SGLT2 expression was observed in CD in comparison with T1D and CTRL, as expected; GLUT1 was significantly more expressed in T1D compared to CTRL. SGLT2 expression was quantified at much lower levels than other transporters, with no differences between groups. SGLT2 expression was confirmed by immunohistochemistry in a restricted number of enterocytes lining in the mucosa of intestinal villi, also shown on immunofluorescence. CONCLUSIONS: Our results show that glucose transporters expression in duodenal mucosa of subjects with T1D, except an increased GLUT1, is not different from that observed in healthy controls. The expression of SGLT2 in human duodenal mucosa, although at low intensity, represents a novel finding.

Reduced PD-1 expression on circulating follicular and conventional FOXP3+ Treg cells in children with new onset type 1 diabetes and autoantibody-positive at-risk children.

Autoantibodies (AAbs) are a hallmark of Type 1 diabetes (T1D). Alterations in the frequency and phenotype of follicular helper (Tfh) T cells have been previously documented in patients with type 1 diabetes (T1D), but the contribution of follicular regulatory T (Treg) cells, which are responsible for suppressing AAb development, is less clear. Here, we investigated the frequency and activation status of follicular (CXCR5+) and conventional (CXCR5-) Treg cells in the blood of children with new-onset T1D, and children with risk for developing T1D (AAb-positive) and compared them to AAb-negative controls. Blood follicular and conventional Treg cells were higher in frequency in children with new onset T1D, but expressed reduced amounts of PD-1 as compared to AAb-negative children. Interestingly, the proportion of circulating FOXP3+ Tregs expressing PD-1 was also reduced in AAb-positive at-risk children as compared to AAb-negative controls, suggesting its potential use as a biomarker of disease progression. Follicular Treg cells were reduced in frequency in the spleens of prediabetic NOD mice as they became older and turned diabetic. Interestingly, PD-1 expression declined also on circulating follicular and conventional Treg cells in prediabetic NOD mice as they aged. Together, these findings show that the frequency of circulating follicular and conventional Treg cells and their levels of PD-1 change with disease progression in children at-risk for developing T1D and in NOD mice.

Study of 2009 H1N1 Pandemic Influenza Virus as a Possible Causative Agent of Diabetes.

Context: Recent studies have suggested that influenza A virus (IAV) might be involved in the etiology of diabetes. Objective and Methods: To address this question, we tested the ability of H1N1 pandemic IAV to infect, replicate, and damage human ß cells/pancreatic islets in vitro and induce pancreatic damage and/or glucose metabolism alterations in chemical and autoimmune models of ß cell damage in vivo. Moreover, we looked for direct and/or indirect evidence of correlation between IAV infection and autoimmunity/diabetes in humans. Results: Human H1N1 A/California/2009-derived viruses infected human pancreatic islets in vitro, inducing a proinflammatory response associated with substantial increases of CXCL9 and CXCL10 release. In vivo, infected mice showed a clear susceptibility to the virus, with its localization also found in extrapulmonary organs, including the pancreas. Infection was able to induce mild modifications of glycemia in C57B6 mice after chemical damage of islets but did not modulate the autoimmune damage of islets in NOD mice. One of 69 nasopharyngeal swabs collected from patients at the onset of type 1 diabetes yielded positive results for IAV. Pancreas sections from 17 organ donors available from the Network for Pancreatic Organ Donors With Diabetes showed the persistence of CXCL10-positive cells in islet autoimmunity-positive subjects; however, extremely rare cells stained for viral RNA and not preferentially in autoimmune subjects. Conclusion: Influenza H1N1 pdm strains are able to infect and replicate in mammalian pancreatic cells both in vitro and in vivo but did not cause any functional impairment consistent with diabetes.

Duodenal Mucosa of Patients With Type 1 Diabetes Shows Distinctive Inflammatory Profile and Microbiota.

Context: Increasing evidences suggest a correlation between gut and type 1 diabetes (T1D). Objective: The objective of this study is to evaluate the gut inflammatory profile and microbiota in patients with T1D compared with healthy control (CTRL) subjects and patients with celiac disease (CD) as gut inflammatory disease controls. Design/Setting/Participants: The inflammatory status and microbiome composition were evaluated in biopsies of the duodenal mucosa of patients with T1D (n = 19), in patients with CD (n = 19), and CTRL subjects (n = 16) recruited at San Raffaele Scientific Institute, in Milan, Italy, between 2009 and 2015. Main Outcome Measures: Inflammation was evaluated by gene expression study and immunohistochemistry. Microbiome composition was analyzed by 16S ribosomal RNA gene sequencing. Results: An increased expression of CCL13, CCL19, CCL22, CCR2, COX2, IL4R, CD68, PTX3, TNFα, and VEGFA was observed in patients with T1D compared with CTRL subjects and patients with CD. Immunohistochemical analysis confirmed T1D-specific inflammatory status compared with healthy and CD control tissues, mainly characterized by the increase of the monocyte/macrophage lineage infiltration. The T1D duodenal mucosal microbiome results were different from the other groups, with an increase in Firmicutes and Firmicutes/Bacteroidetes ratio and a reduction in Proteobacteria and Bacteroidetes. The expression of genes specific for T1D inflammation was associated with the abundance of specific bacteria in the duodenum. Conclusions: This study shows that duodenal mucosa in T1D presents disease-specific abnormalities in the inflammatory profile and microbiota. Understanding the mechanisms underlying these features is critical to disentangle the complex pathogenesis of T1D and to gain new perspectives for future therapies targeting the intestine.

Efficacy of Bariatric Surgery in Type 2 Diabetes Mellitus Remission: the Role of Mini Gastric Bypass/One Anastomosis Gastric Bypass and Sleeve Gastrectomy at 1 Year of Follow-up. A European survey.

BACKGROUND: A retrospective study was undertaken to define the efficacy of both mini gastric bypass or one anastomosis gastric bypass (MGB/OAGB) and sleeve gastrectomy (SG) in type 2 diabetes mellitus (T2DM) remission in morbidly obese patients (pts). METHODS: Eight European centers were involved in this survey. T2DM was preoperatively diagnosed in 313/3252 pts (9.62%). In 175/313 patients, 55.9% underwent MGB/OAGB, while in 138/313 patients, 44.1% received SG between January 2006 and December 2014. RESULTS: Two hundred six out of 313 (63.7 %) pts reached 1 year of follow-up. The mean body mass index (BMI) for MGB/OAGB pts was 33.1 ± 6.6, and the mean BMI for SG pts was 35.9 ± 5.9 (p < 0.001). Eighty-two out of 96 (85.4%) MGB/OAGB pts vs. 67/110 (60.9%) SG pts are in remission (p < 0.001). No correlation was found in the % change vs. baseline values for hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) in relation to BMI reduction, for both MGB/OAGB or SG (ΔFPG 0.7 and ΔHbA1c 0.4 for MGB/OAGB; ΔFPG 0.7 and ΔHbA1c 0.1 for SG). At multivariate analysis, high baseline HbA1c [odds ratio (OR) = 0.623, 95% confidence interval (CI) 0.419-0.925, p = 0.01], preoperative consumption of insulin or oral antidiabetic agents (OR = 0.256, 95% CI 0.137-0.478, p = <0.001), and T2DM duration >10 years (OR = 0.752, 95% CI 0.512-0.976, p = 0.01) were negative predictors whereas MGB/OAGB resulted as a positive predictor (OR = 3.888, 95% CI 1.654-9.143, p = 0.002) of diabetes remission. CONCLUSIONS: A significant BMI decrease and T2DM remission unrelated from weight loss were recorded for both procedures if compared to baseline values. At univariate and multivariate analyses, MGB/OAGB seems to outperform significantly SG. Four independent variables able to influence T2DM remission at 12 months have been identified.

Necrobiosis Lipoidica Diabeticorum: A pediatric case report.

INTRODUCTION: Necrobiosis lipoidica (NL) is a rare chronic granulomatous dermatitis that usually appears in the lower extremities. It affects about 0.3-1.2% of diabetic patients, the majority of whom have type 1 diabetes. The etiology and pathogenesis of this disorder are still unclear. NL is characterized by skin rash that usually affects the shins. The average onset is 30 years, with females being affected more commonly. There are very few reported cases of necrobiosis lipoidica in children. CASE REPORT: We report a case of a 16 year old girl affected by type 1 diabetes mellitus (15 years disease duration) who developed an erythematous nodular rash on the lower extremities and interscapular area. In the suspect of necrobiosis lipoidica, a skin biopsy was performed (lower extremities and interscapular area). The microscopic evaluation of the pretibial lesions was suggestive of necrobiosis lipoidica. The smaller lesions in the interscapular area showed signs of perivascular dermatitis which could be consistent with early stages of necrobiosis lipoidica. Local treatment with tacrolimus determined a progressive improvement of the lesions. CONCLUSION: In patients with T1DM, diagnosis of NL of the lower legs is usually unequivocal. However, diagnosis may be more challenging in the presence of lesions with recent onset and/or atypical clinical presentation and unusual site. In these cases, NL must always be taken in consideration in order to avoid misdiagnosis, wrong/late treatment decisions and progression to ulceration.

Occurrence of celiac disease after onset of type 1 diabetes: a 6-year prospective longitudinal study.

OBJECTIVE: To investigate the prevalence of celiac disease in a large cohort of children and adolescents at the onset of type 1 diabetes and the occurrence of new cases during a 6-year follow-up. METHODS: We prospectively studied, by repeated serologic screening, 274 consecutive patients at the onset of type 1 diabetes (age [mean +/- standard deviation]: 8.28 +/- 4.65 years) for 6 subsequent years. One patient had a diagnosis of celiac disease before the onset of diabetes. The immunoglobulin A-antiendomysium antibody test was selected as the screening test; patients with positive results (++ or +++) or with 2 consecutive weak positive tests (+) were considered appropriate for the jejunal biopsy. RESULTS: At diabetes onset, 15 (5.5%) of 273 patients tested positive with the antiendomysium test; jejunal biopsy was performed in 10, and celiac disease was diagnosed in 9. The prevalence of biopsy-confirmed celiac disease at the manifestation of diabetes was 3.6% (10 of 274 patients). Twelve more patients with a negative antiendomysium antibody test at diabetes onset tested positive during the follow-up within 4 years; 10 of them had biopsies performed, and 7 had celiac disease. Therefore, the overall prevalence of biopsy-confirmed celiac disease in the entire cohort of patients was 6.2%. The age at diabetes onset in patients with and without celiac disease was not different (7.88 +/- 5.69 vs 8.3 +/- 4.58 years). The majority of cases of celiac disease were asymptomatic in their presentation, and no signs of overt malnutrition were documented. CONCLUSIONS: The prevalence of celiac disease in patients with type 1 diabetes is approximately 20 times higher than in the general population. Sixty percent of cases are already present at diabetes onset, mostly undetected, but an additional 40% of patients develop celiac disease a few years after diabetes onset. Extending screening programs for celiac disease after the onset of type 1 diabetes is recommended, even in the absence of clinical symptoms.