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Background Early ocular neurodegenerative signs of diabetic neuropathy (DN) can be found in children and adolescents with type 1 diabetes (T1D). No data are available on the potential role of polymorphisms in miRNAs genes in predisposing T1D subjects to these signs. Aims To determine whether MIR146A rs2910164 and MIR128A rs11888095 polymorphisms are associated with early retinal and corneal neurodegenerative changes in pediatric patients with T1D. Methods A total of 140 T1D children/adolescents underwent spectral domain-optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM) with measurement of retinal and corneal nerve fiber parameters. Risk factors for diabetes complications (diabetes duration, blood pressure, HbA1c) were recorded. Genotyping of rs2910164 and rs1188095 SNPs and genotype–phenotype association analysis were performed. Results The C allele of rs2910164 in MIR146A was associated with higher values of IVCM parameters and minimum rim width (MRW) of the peripapillary region of optic nerve head measured in the retina, whereas the T allele of rs1188095 in MIR128A was associated with a significant impairment of them. Multiple regression analysis showed that MIR146A and MIR128A polymorphisms were significantly associated with corneal nerve fiber length (beta = 0.225 and − 0.204, respectively) and other IVCM parameters, independently from age, diabetes duration, HbA1c and systolic blood pressure percentile. Similar results were found for MRW (beta = 0.213 and − 0.286, respectively). Conclusions These results provide new insight into the genetic predisposition to DN showing that two polymorphisms in MIR146A and MIR128A genes could significantly contribute to the development of early ocular preclinical signs of DN.

Changes in the desaturation activity of LC-PUFAs may influence insulin sensitivity by modulating the relative abundance of omega-3. The aim of this cross-sectional study was to assess the association between genetic variants of fatty acid desaturase cluster genes (FADS1, FADS2, FADS3) and insulin sensitivity in a cohort of children and adolescents with obesity. Anthropometric evaluation, lipid profile, glucose metabolism parameters and the genotype of rs1535 on FADS2 gene were assessed. In 162 obese children and adolescents (12.6 ± 2.3 years; BMI 30.9 ± 7.3), we found a significant association between an index of insulin sensitivity, i.e., Matsuda index, and rs1535 (B = -0,192; p = 0.008), BMI (B = -0,003; p 0.001), and triglycerides (B = -0,034; p 0.001), independent of age and sex [R² = 0.35; p = 0.001]. In conclusion, FADS cluster variants were associated with insulin sensitivity in a population of children and adolescents with obesity, contributing to identify individuals who may benefit from personalised prevention and treatment nutritional strategies since childhood.

To assess whether combining glucose shape and 2-h glucose concentration during an oral glucose tolerance test (OGTT) may help identifying normal glucose tolerant obese children/adolescents with an impaired glucose tolerant (IGT)-like metabolic profile in term of insulin sensitivity (Matsuda index) and β-cell function (disposition index: DI).In total, 654 non-diabetic obese children/adolescents underwent a 2 h OGTT. The whole population was classified according to 2-hour plasma glucose ( 100, 100-119, 120-139, 140-200 mg/dL) and glucose shape (monophasic or biphasic). Monophasic morphology was characterized by an increase in OGTT glucose concentration followed by a decline of at least 4.5 mg/dL, a biphasic response was defined as a decrease in glucose after an initial increase, followed by a second increase of ≥ 4.5 mg/dL. A subset of 69 participants had also a prolonged OGTT to estimate β-cell function in "biphasic" versus "monophasic" patients.Matsuda index and DI decreased across 2-h glucose categories (both p 0.001) and were lower in monophasic compared with biphasic children, independently of 2-h glucose category (both p 0.001, both p for glucose category×shape interaction 0.05). Normal glucose tolerant children with 2-h glucose of 120-139 mg/dl and monophasic glucose shape did not differ from IGT children, as regards Matsuda index and DI (both p 0.05). Among children undergoing a prolonged OGTT, those with a monophasic glucose shape had worse β-cell function, modeled as proportional control, than those with a biphasic shape (p = 0.031).A monophasic OGTT glucose shape is associated with unfavorable glucose metabolism independently of 2-h glucose concentration. Children combining monophasic shape and normal-high 2-h glucose have an IGT-like glucose metabolism.

In order to assess whether flavin-containing monooxygenase-3 (FMO3) might be involved in early cardiovascular risk, we assessed adiposity and traditional metabolic variables in children/adolescents grouped according to their genotypes in two FMO3 exonic polymorphisms, rs2266782 (E158K) and rs2266780 (E308G), which are in linkage disequilibrium and have been associated with decreased FMO3 activity. Among 776 children/adolescents (10.8 ± 2.2 years) recruited from the general population (452) and from our obesity outpatient clinic (324), the 68 carrying either the 158K-308G/158K-308E or the 158K-308G/158K-308G diplotype had lower mean z-BMI and prevalence of obesity compared to their 708 peers carrying any of the other diplotypes (0.39 vs 0.80, p = 0.01; OR = 0.39[0.17-0.87], p = 0.018, respectively), and to the sub-sample of 303 children carrying the major diplotype (158E-308E/158E-308E) (0.39 vs 0.87, p = 0.008; OR = 0.35[0.16-0.81], p = 0.014, respectively). They also had lower z-BMI-adjusted lnHOMA-IR compared to all the other children (0.75 vs 0.97, p = 0.001) and those carrying the major diplotype, (0.75 vs 0.98, p = 0.03), as well as lower z-BMI-adjusted iln-triglycerides compared to all the other children (3.98 vs 4.17, p = 0.037). These associations provide the first evidence that FMO3 may be involved in early body weight, insulin sensitivity, and lipid regulation in humans.