The bidirectional association of C-peptide with cardiovascular risk in nondiabetic adults and patients with newly diagnosed type 2 diabetes mellitus: a retrospective cohort study.

BACKGROUND: Recent literature reported the biological role of C-peptide, but this role is still controversial and unclear. The primary aim of this study was to investigate associations between C-peptide and cardiovascular biomarkers as well as events. METHODS: A total of 55636 participants who had a health examination from 2017 to 2021 were included. Of them, 6727 participants visited the hospital at least twice. Cardiovascular biomarkers like high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured and their relationships with fasting C-peptide were evaluated for all participants. Cardiovascular events were obtained during the last visit and their associations with C-peptide were evaluated for those participants who visited the hospital at least twice. RESULTS: Among the included participants, 11.1% had a previous type 2 diabetes mellitus (T2DM). In the participants without previous T2DM, the relationships between fasting C-peptide and hs-CRP and hs-cTnT were negative if the value of fasting C-peptide was < 1.4 ng/mL and positive if the value was ≥ 1.4 ng/mL. These relationships remained significant after adjusting for hemoglobin A1c, insulin resistance index, and its interaction with C-peptide, even if the participants were stratified by glucose metabolism status or levels of insulin resistance index. Hazard ratios of cardiovascular events were first decreased and then increased with the increasing of baseline C-peptide levels, though these associations became unsignificant using the multivariate Cox regression model. Unlike the participants without previous T2DM, the associations of C-peptide with cardiovascular biomarkers and events were not significant in the patients with previous T2DM. CONCLUSIONS: The associations of C-peptide with cardiovascular biomarkers and events were different between the participants without previous T2DM and those with previous T2DM. The effect of C-peptide on cardiovascular risk may be bidirectional, play a benefit role at a low level, and play a harmful role at a high level in the nondiabetic adults and the patients with newly diagnosed T2DM.

MiR-199a is overexpressed in plasma of type 2 diabetes patients which contributes to type 2 diabetes by targeting GLUT4.

Decreased GLUT4 expression and impaired GLUT4 cell membrane translocation are involved in type 2 diabetes mellitus (T2DM) pathogenesis so the factors impacting GLUT4 expression may be associated with T2DM. In this study, we identified four miRNAs: miR-31, miR-93, miR-146a, and miR-199a which suppress GLUT4 expression in HEK293T cells. Subsequently, we determined expression of these four miRNAs in plasma samples of T2DM patients, T2DM susceptible individuals, and healthy controls and found miR-199a was overexpressed in patients' plasma compared with healthy control. Because the miR-199a binding site in GLUT4 3'UTR is highly conserved among vertebrates, we detected the glucose uptake in rat L6 myoblast cells through gain- and loss-of-function of miR-199a. We found that miR-199a can repress glucose uptake in L6 cells, which was rescued by GLUT4 overexpression. These results indicate that T2DM patients may have a high level miR-199a that reduce GLUT4 expression and contribute to the insulin resistance. Hence, miR-199a may be a novel biomarker for risk estimation and classification in T2DM patients.

[Risks of type 2 diabetes mellitus and impaired glucose regulation among elderly patients with essential hypertension: a 10-years cohort study].

OBJECTIVE: To explore the incidence of type 2 diabetes mellitus (T2DM) and impaired glucose regulation (IGR) among elderly patients with and without hypertension during a follow-up period of 10 years. METHODS: The subjects were elderly patients (> 60 years old) undergoing annual health examinations at our hospital. And the previously diagnosed T2DM and IGR patients were excluded. And the incidence and risk factors were analyzed by Kaplan-Meier method and COX's proportional hazard. RESULTS: Among a total of 1136 subjects, 582 were enrolled. They were divided into essential hypertension group (HT, n = 384) and non-essential hypertension group (NHT, n = 198) (including new-onset 67 subjects). During a 10-year follow-up, the incidence of new-onset diabetes was 27.6% in HT group and 18.7% in NHT group (HR = 1.48; 95%CI: (1.07 - 2.04), P < 0.05). And the incidence density of T2DM were 33.8‰ and 20.6‰ respectively in two groups. There was no difference in the prevalence of IGR among HT and NHT groups and no difference was found in the prevalence of T2DM or IGR among new-onset HT and NHT groups. The independent risk factors of T2DM was dyslipidemia (HR = 1.459; 95%CI: 1.027 - 2.072, P < 0.05) and hypertension (HR = 1.516; 95%CI: 1.039 - 2.212, P < 0.05) based upon the COX's proportional hazard analysis. Dyslipidemia (HR = 1.545; 95%CI: 1.087 - 2.195, P < 0.05) and hypertension (HR = 1.524; 95%CI: 1.044 - 2.224, P < 0.05) were also independent risk factors of abnormal glycometabolism (T2DM and IGR). Kaplan-Meier analysis indicated that the accumulative incidence of DM and abnormal glycometabolism was different between the HT and NHT groups. CONCLUSION: The DM risk is 1.516 folds higher in elderly patients with HT than in those without. According to multivariate analysis, hypertension and dyslipidemia are independent risk factors of T2DM and abnormal glycometabolism (T2DM and IGR).

Effects of a prolonged diet regimen on autophagic function in rat islets with aging.

The prevalence of type 2 diabetes increases with age-associated increased susceptibility of islet ß-cells and altered dietary patterns, in part because of insufficient compensation of ß-cell functional mass in the face of increasing insulin resistance. However, the underlying mechanisms have not been fully elucidated. In the present study, we investigated the effects of a long-term calorie-restricted (CR) or high-fat (HF) diet compared to a normal ad libitum diet on ß-cell structure-function relationships and autophagy in the islets of 3- and 24-month-old Fischer 344 rats. Aging and the HF diet decreased the ß-cell-to-islet area ratio, disorganized the islet structure, and increased the expression of senescence markers. Aging and the long-term HF diet also decreased autophagy-related proteins, which suggests compromised autophagic function. These findings were further corroborated by increased p62 accumulation and polyubiquitin aggregates observed with aging and the HF diet intervention; these are cardinal markers of attenuated autophagic function. It is important to note that the 24-month-old rats maintained on the CR diet closely mimicked the 3-month-old rats, which indicates that a long-term CR diet can delay islet aging and prevent the decline in the autophagic function of islets during the aging process. Taken together, our results indicate an autophagy-dependent mechanism responsible for islet function in older people or those with altered dietary patterns and lay the foundations for future research leading to novel therapeutic strategies for treating diabetes.

Effects of body mass index and weight change on mortality in older men with impaired glucose regulation.

OBJECTIVES: To assess the effect of baseline body mass index (BMI) status and weight change on mortality in older men with impaired glucose regulation (IGR). METHODS: Eight hundred eighty-five men with IGR aged 60 to 90 were included. Baseline and endpoint weight were measured. All-cause and cardiovascular mortality were observed during a median follow-up period of 10years. Multivariate Cox regressions were used to estimate associations between BMI, weight change and mortality. RESULTS: Relative to normal weight, overweight was associated with lower all-cause mortality (hazard ratios, HRs [95% confidence interval, 95% CI]: 0.57 [0.41, 0.78]) and cardiovascular mortality (0.52 [0.29, 0.93]), whereas obesity did not significantly decrease or increase the mortality risk. Furthermore, compared to weight stability, all types of weight change led to increased mortality risk, except small weight gain. Specifically, after adjustment for covariates and the initial weight, the HRs (95% CI) of large weight loss were 1.64 (1.15, 2.34) for all-cause mortality and 1.85 (1.10, 3.14) for cardiovascular mortality, and the HRs (95% CI) of large weight gain were 1.55 (1.01, 2.40) for all-cause mortality and 2.11 (1.04, 4.30) for cardiovascular mortality. Similar associations were observed when weight change was redefined in sensitivity analyses. CONCLUSIONS: Both BMI at baseline and weight change have independent U-shaped associations with all-cause and cardiovascular mortality among older men with IGR. The present study suggests that older men with IGR may ensure their best survival by being overweight at baseline or by maintaining their weight regardless of their baseline weight status.

Clinical and pathological analysis of renal damage in elderly patients with type 2 diabetes mellitus.

The aim of this study was to investigate the causes and influential factors of renal damage in elderly patients with type 2 diabetes mellitus (T2DM). Clinical data and pathological findings at autopsy of 161 elderly T2DM patients died between October 1994 and August 2011 were retrospectively reviewed. The mean age of these patients was 80.8 ± 8.3 years (range 60-105 years). The incidences of diabetic nephropathy (DN), non-diabetic renal diseases (NDRD), and DN complicated with NDRD were 31.1, 62.7, and 16.2 %, respectively. In patients with NDRD, the incidence of hypertensive renal damage (HRD) was 54.7 %. In the factors causing renal damage, DN and NDRD accounted for 1/3 and 2/3, respectively. HRD accounted for the largest proportion of NDRD. Blood pressure control may provide additional benefits for elderly T2DM patients by preventing and delaying the occurrence and development of renal disease.

Association of calpain-10 rs2975760 polymorphism with type 2 diabetes mellitus: a meta-analysis.

Type 2 diabetes mellitus (T2DM) accounts for the majority of diabetes cases and affects a significant proportion of the adult population worldwide. Calpain-10 has been implicated in the development of type 2 diabetes, and some polymorphisms in the CAPN10 gene have been associated with an increased risk of developing this disease. Several molecular epidemiological studies were conducted in recent years to evaluate the association between the CAPN10 rs2975760 polymorphism and T2DM risk in diverse populations. However, the results remain conflicting rather than conclusive. We performed a meta-analysis of 8 case-control studies that included 2758 T2DM cases and 2762 case-free controls. We assessed the strength of the association, using odds ratios (ORs) with 95% confi dence intervals (CIs). Overall, this meta-analysis showed that the CAPN10 rs2975760 polymorphism was not associated with a significantly type 2 diabetes risk in three genetic models. However, after excluding two study for its heterogeneity, a significantly increased risk was found in all comparisons (for C vs T: OR=1.14, 95% CI=1.03-1.27, I (2)=0, P heterpgeneity=0.420, P b=0.012; for TC vs TT: OR=1.15, 95% CI=1.01-1.30, I (2)=3.8%, P heterpgeneity=0.392, P b=0.030; for CC+TC vs TT: OR=1.16, 95% CI=1.03-1.31, I (2)=3.7%, P heterpgeneity=0.393, P b=0.015). No publication bias was found in the present study. This meta-analysis suggests that the C allele of the CAPN10 rs2975760 polymorphism is associated with an increased T2DM risk. Further large and well-designed studies are needed to confi rm this association.