Population-based and family-based studies on the protein tyrosine phosphatase non-receptor 22 gene polymorphism and type 1 diabetes: A meta-analysis

Purpose

Studies investigating the association between PTPN22 gene C1858T polymorphism and type 1 diabetes (T1D) susceptibility among Caucasian population have reported conflicting results. To investigate this inconsistency, we performed a meta-analysis of all available studies dealing with the relationship between the PTPN22 C1858T polymorphism and T1D.

Methods

Databases including PubMed, Web of Science, and EMBASE were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association.

Results

In total, 33 population-based studies with 22, 485 cases and 35, 292 controls, 9 family-based studies involving 7276 families were included. Under the random-effects model, the per-allele overall OR of the C1858T polymorphism for T1D was 1.89 (95% CI: 1.76–2.02, P < 10^− 5) by pooling all available case–control studies. In addition, we found significant evidence for overtransmission of the risk T allele in family-based studies (overall OR _TDT = 1.58, 95% CI: 1.43–1.74; P < 10^− 5). The summary OR from case–control and family-based association studies was 1.81 (95% CI: 1.70–1.93, P < 10^− 5).

Conclusions

In conclusion, this meta-analysis suggests that C1858T polymorphism in PTPN22 is associated with elevated T1D risk among Caucasian population.     

Impact of apolipoprotein A1- or lecithin:cholesterol acyltransferase-deficiency on white adipose tissue metabolic activity and glucose homeostasis in mice

High density lipoprotein (HDL) has attracted the attention of biomedical community due to its well-documented role in atheroprotection. HDL has also been recently implicated in the regulation of islets of Langerhans secretory function and in the etiology of peripheral insulin sensitivity. Indeed, data from numerous studies strongly indicate that the functions of pancreatic β-cells, skeletal muscles and adipose tissue could benefit from improved HDL functionality. To better understand how changes in HDL structure may affect diet-induced obesity and type 2 diabetes we aimed at investigating the impact of Apoa1 or Lcat deficiency, two key proteins of peripheral HDL metabolic pathway, on these pathological conditions in mouse models. We report that universal deletion of apoa1 or lcat expression in mice fed western-type diet results in increased sensitivity to body-weight gain compared to control C57BL/6 group. These changes in mouse genome correlate with discrete effects on white adipose tissue (WAT) metabolic activation and plasma glucose homeostasis. Apoa1-deficiency results in reduced WAT mitochondrial non-shivering thermogenesis. Lcat-deficiency causes a concerted reduction in both WAT oxidative phosphorylation and non-shivering thermogenesis, rendering lcat^?/? mice the most sensitive to weight gain out of the three strains tested, followed by apoa1^?/? mice. Nevertheless, only apoa1^?/? mice show disturbed plasma glucose homeostasis due to dysfunctional glucose-stimulated insulin secretion in pancreatic β-islets and insulin resistant skeletal muscles. Our analyses show that both apoa1^?/? and lcat^?/? mice fed high-fat diet have no measurable Apoa1 levels in their plasma, suggesting no direct involvement of Apoa1 in the observed phenotypic differences among groups.     

Factors Associated With Insulin Pump Discontinuation in Adults With Diabetes: A Time-to-Invent Analysis and Prediction Model

ObjectiveInsulin pump discontinuation has mostly been studied in children and adolescents living with diabetes. We aimed to assess the rate of insulin pump continuation in a population of adult patients with diabetes, at 18 months after initiation; determine the factors associated with pump discontinuation; and develop a simple prediction model.MethodsThis single-center, retrospective study included all adult patients with type 1 diabetes or type 2 diabetes who started insulin pump treatment between January 2015 and June 2018. The exclusion criteria were pregnancy, short-term pregnancy plans, and insulin pump discontinuation within the previous 6 months. The probability of insulin pump continuation after 18 months was estimated using the Kaplan-Meier method. Factors associated with insulin pump discontinuation were studied using a Cox regression model, and an exponential model was built for prediction purposes.ResultsThe study included 315 patients. The mean age was 41 years, the mean duration of diabetes was 16 years, 50% were men, 74% had type 1 diabetes, and the mean hemoglobin A1c level was 9.1% (76 mmol/mol). After 18 months, the rate of insulin pump continuation was 0.80 (95% Confidence Interval (CI), 0.76-0.85). By multivariate analysis, the occurrence of severe hypoglycemia in the previous year was associated with insulin pump discontinuation (hazard ratio, 2.42; 95% CI, 1.30-4.51), while other factors did not reach statistical significance.ConclusionInsulin pump discontinuation occurred in 20% of patients at 18 months after initiation and was mainly associated with a recent history of severe hypoglycemia. The type of diabetes and glycemic control at baseline were not associated with treatment discontinuation.     

Basal Insulin Degludec and Glycemic Control Compared to Aspart Via Insulin Pump in Type 1 Diabetes (BIGLEAP): A Single-Center,Open-Label,Randomized, Crossover Trial

ObjectiveWe compared the efficacy of the second-generation basal insulin degludec (IDeg) to that of insulin aspart via pump using continuous glucose monitoring in patients with well-controlled type 1 diabetes.MethodsIn this 40-week, single-center, randomized, crossover-controlled trial, adults with well-controlled type 1 diabetes (hemoglobin A1C of <7.5% [<58 mmol/mol]) (N = 52) who were using an insulin pump and continuous glucose monitoring were randomized to 1 of 2 treatments for a 20-week period: a single daily injection of IDeg with bolus aspart via pump or a continuous subcutaneous insulin infusion (CSII) with aspart, followed by crossover to the other treatment. The primary endpoint was time in range (70-180 mg/dL) during the final 2 weeks of each treatment period.ResultsFifty-two patients were randomized and completed both treatment periods. The time in range for IDeg and CSII was 71.5% and 70.9%, respectively (P = .553). The time in level 1 hypoglycemia for the 24-hour period with IDeg and CSII was 2.19% and 1.75%, respectively (P = .065). The time in level 2 hypoglycemia for the 24-hour period with IDeg and CSII was 0.355% and 0.271%, respectively (P = .212), and the nocturnal period was 0.330% and 0.381%, respectively (P = .639). The mean standard deviation of blood glucose levels for the 24-hour period for IDeg and CSII was 52.4 mg/dL and 51.0 mg/dL, respectively (P = .294). The final hemoglobin A1C level for each treatment was 7.04% (53 mmol/mol) with IDeg, and 6.95% (52 mmol/mol) with CSII (P = .288). Adverse events were similar between treatments.ConclusionWe observed similar glycemic control between IDeg and insulin aspart via CSII for basal insulin coverage in patients with well-controlled type 1 diabetes.     

Pragmatic Clinic-Based Investigation of Glycemic Variability in Patients With Type 1 Diabetes in Routine Clinical Practice and Its Association With Cardiovascular Autonomic Neuropathy: A Pilot Study

ObjectiveTo evaluate the relationship between markers of glycemic variability (GV), assessed by blinded continuous glucose monitoring (CGM), and cardiovascular autonomic neuropathy (CAN) in patients with type 1 diabetes (T1D).MethodsGV indices, such as SD and coefficient of variation were obtained by blinded CGM through an electrode inserted into the subcutaneous tissue for at least 3 consecutive days. CAN was assessed by cardiovascular reflex tests and HRV.ResultsFifteen T1D patients were included: 7 (46.7%) women, aged 47.1 ± 11.6 years, with a diabetes duration of 26 years (20 to 29.5 years). Five patients (25%) were excluded from our study. The majority of our patients presented glycated hemoglobin (60%), SD (86.3%), and coefficient of variation (60%) above the established goals. Patients with defined CAN had a longer diabetes duration, higher glycated hemoglobin levels, lower glomerular filtration rate, lower prevalence of indices related to hypoglycemic stress, and short-term GV indices compared with patients without CAN.ConclusionOur study showed an inverse association between GV and CAN. The most important risk factors associated with CAN were age, diabetes duration, and markers of chronic hyperglycemia. Furthermore, the difficulty in the interpretation of data extracted from the blinded CGM system, which also requires a minimum of 3 capillary blood glucose measurements for calibration, should be carefully analyzed to ensure the accuracy and usefulness of the blinded CGM system as a tool for diabetes management in developing countries. Further studies are necessary to establish the role of GV in the development of CAN in patients with T1D.