Anti-atherosclerotic effects of sitagliptin in patients with type 2 diabetes mellitus

Risk of Atherosclerosis Due to HMGB1-dependent Platelet-derived Microparticles in Patients with Type 2 Diabetes Mellitus

We measured high mobility group box 1 protein (HMGB1) and platelet-derived microparticles (PDMP) in blood samples from patients with untreated type 2 diabetes mellitus (T2DM). We examined the effects of a combination of sodium/glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors. Multiple regression analysis of HMGB1 was conducted on data from 252 patients in our previously reported T2DM-related clinical study. The results revealed significant correlations between HMGB1 and PDMP, soluble CD40 ligand, plasminogen activator inhibitor-1, and soluble E-selectin in multivariate analysis. Based on the HMGB1 levels before treatment with combination, 46 T2DM patients in the study were classified into two groups, high and low. The high HMGB1 group showed a significantly lower adiponectin level and higher PDMP production than the low HMGB1 group. T2DM risk significantly and positively correlated with HMGB1 and PDMPs. HMGB1-induced PDMP production was simulated in vitro using healthy platelets. Furthermore, The combination of a SGLT2 inhibitor and a DPP-4 inhibitor significantly reduced HMGB1 and PDMP levels. These results suggest that in addition to abnormal glucose metabolism, HMGB1-dependent PDMP production and the resulting development of atherosclerosis are also a concern in patients with T2DM.

Comparison of teneligliptin and other gliptin-based regimens in addressing insulin resistance and glycemic control in type 2 diabetic patients: a cross-sectional study

INTRODUCTION

The objective of this study was to compare the effects of teneligliptin-based regimens and other gliptin-based regimens with respect to insulin resistance and glycemic control in patients with type 2 diabetes mellitus (T2DM).

METHODS

We enrolled T2DM subjects, inadequately controlled with metformin and glimepiride and taking one of the gliptins, and divided them into two groups, i.e. group 1 (teneligliptin-based regimens) and group 2 (other gliptin-based regimens). Fasting plasma insulin, adiponectin levels, homeostatic model assessment for insulin resistance (HOMA-IR), glycated hemoglobin (HbA1c), and fasting blood glucose (FBG) were measured and compared. Costs of different gliptins were noted, and mean cost of per day therapy was compared.

RESULTS

Eighty-six subjects participated in this study (43 each in group 1 and group 2). No significant differences were observed in FBG, HbA1c, insulin levels, and HOMA-IR, but the trend was in favor of teneligliptin-based regimens. A significantly higher number of subjects achieved HbA1c target in group 1 (P < 0.001). Teneligliptin had significantly lower cost of per day therapy as compared to other dipeptidyl peptidase-4 inhibitors.

CONCLUSION

Teneligliptin seems to be cost-effective and safer option in T2DM subjects who were not adequately controlled with metformin and sulfonylureas. However, further prospective studies are needed.

Chemokines in Prediabetes and Type 2 Diabetes: A Meta-Analysis

Background

A growing number of studies found inconsistent results on the role of chemokines in the progression of type 2 diabetes (T2DM) and prediabetes (PDM). The purpose of this meta-analysis was to summarize the results of previous studies on the association between the chemokines system and T2DM/PDM.

Methods

We searched in the databases, PubMed, Web of Science, Embase and Cochrane Library, for eligible studies published not later than March 1, 2020. Data extraction was performed independently by 2 reviewers, on a standardized, prepiloted form. Group differences in chemokines concentrations were summarized using the standardized mean difference (SMD) with a 95% confidence interval (CI), calculated by performing a meta-analysis using the random-effects model.

Results

We identified 98 relevant studies that investigated the association between 32 different chemokines and T2DM/PDM. Altogether, these studies involved 14,708 patients and 14,574 controls. Results showed that the concentrations of CCL1, CCL2, CCL4, CCL5, CCL11, CXCL8, CXCL10 and CX3CL1 in the T2DM patients were significantly higher than that in the controls, while no difference in these concentrations was found between the PDM patients and controls.

Conclusion

Progression of T2DM may be associated with elevated concentrations of chemokines.

Meta-Analysis Registration

PROSPERO, identifier CRD42019148305.

[Sitagliptin inhibits lipopolysaccharide-induced inflammatory response in human gingival fibroblasts by blocking nuclear factor-κB signaling pathway]

OBJECTIVES

This study was performed to clarify the effects of sitagliptin on Porphyromonas gingivalis-lipopolysaccharide (LPS)-induced inflammatory response in human gingival fibroblasts (HGFs), explore the molecular mechanism of its roles, and provide a foundation for clinical therapeutics in periodontitis.

METHODS

Healthy gingival samples were collected from the donors. HGFs were isolated with enzymic digestion method and identified. The effects of LPS and sitagliptin on cell viability were detected by cell-counting kit-8 (CCK8). The mRNA levels of inflammatory cytokines, namely, interleukin (IL)-6, IL-8, C-C motif ligand 2 (CCL2), and superoxide dismutase 2 (SOD2), were evaluated by quantity real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immune sorbent assay (ELISA) was used to measure the secretion protein levels of IL-6, IL-8, and CCL2. Western blot analysis was used to further investigate the activation of nuclear factor (NF)-κB signaling pathway. The effect of NF-κB pathway inhibitor BAY11-7082 on LPS-induced HGF inflammatory cytokines at the gene level was verified by qRT-PCR.

RESULTS

Low concentrations of sitagliptin (0.1, 0.25, and 0.5 µmol·L^-1) did not affect HGF growth in 24 and 48 h, whereas high concentrations of sitagliptin (5-1 000 µmol·L^-1) significantly inhibited cell proliferation. Sitagliptin suppressed 5 µg·mL^-1 of LPS-induced IL-6, IL-8, CCL2, and SOD2 gene expression levels in HGF in a concentration-dependent manner. Furthermore, sitagliptin significantly decreased the elevated secretion of IL-6, IL-8, and CCL2 protein induced by LPS. Western blot analysis showed that 0.5 µmol·L^-1 of sitagliptin significantly inhibited LPS-induced NF-κB signaling pathway activation. Results of qRT-PCR analysis indicated that 0.5 µmol·L^-1 of sitagliptin and 5 µmol·L^-1 of BAY11-7082 significantly inhibited LPS-induced IL-6, IL-8, CCL2, and SOD2 gene expressions.

CONCLUSIONS

Sitagliptin could significantly inhibit LPS-induced HGF inflammatory response by blocking the NF-κB signaling pathway activation.

Impact of dipeptidyl peptidase-4 inhibitors on serum adiponectin: a meta-analysis

BACKGROUND

Adiponectin, an adipose-specific protein, is negatively correlated with pro-atherogenic low-density lipoprotein cholesterol (LDL-C) and other cardiovascular risk factors such as insulin resistance. Therefore, low levels of adiponectin are associated with a higher risk for diabetes and cardiovascular disease. Dipeptidyl peptidase-4 inhibitors (DPP4i) have been used for the treatment of type 2 diabetes mellitus (T2DM) as reversible inhibitors through interacting with DPP4 substrate and increase serum incretins such as glucagon-like peptide-1 (GLP-1). The present study aimed to evaluate the effect of DPP4i on serum adiponectin in T2DM patients.

METHODS

The PubMed, Embase, and Cochrane library databases were searched from inception to February 2016. Randomized controlled trials, evaluating the DPP4i (sitagliptin and vildagliptin) versus comparator (placebo or active-comparison), in T2DM patients with duration of ≥ 12 weeks, were identified. Weighted differences in means of adiponectin levels were calculated by using a fixed or random-effects model.

RESULTS

Ten randomized controlled trials, including 1,495 subjects, were identified. Compared with placebo, DPP4i (sitagliptin and vildagliptin) treatment significantly elevated adiponectin levels by 0.74 μg/mL (95% confidence interval [CI], 0.45 to 1.03) relative to that using an active-comparison by 0.00 μg/mL (95% CI, -0.57 to 0.56). Compared with active-comparison, vildagliptin treatment increased adiponectin levels by 0.32 μg/mL (95% CI, -0.01 to 0.65), whereas sitagliptin treatment decreased adiponectin levels by -0.24 μg/mL (95% CI, -1.07 to 0.58). Trials examining effects of other DPP4i were not found.

CONCLUSIONS

Sitagliptin and vildagliptin increased serum adiponectin levels and had no stronger effect than traditional oral antidiabetic drugs. Further trials with larger sample size are needed to confirm the results and investigate the association between serum adiponectin levels and treatment of other DPP-4 inhibitors.

TRIAL REGISTRATION

Registration No in PROSPERO: CRD42016037399 .

Subclinical Inflammation and Endothelial Dysfunction in Young Patients with Diabetes: A Study from United Arab Emirates

Background

The impact of obesity and dyslipidemia on cardiovascular health in adolescents and young adults with diabetes is incompletely understood. This study evaluated the effects of these co-morbidities on markers of inflammation and endothelial dysfunction in young patients with the disease.

Methods

The study investigated sets of inflammatory, endothelial, and adipocyte biomarkers in 79 patients with type 1 diabetes, 55 patients with type 2 diabetes, and 47 controls.

Results

Mean (±SD) age was 20±6 y (median = 17, range = 12–31). Patients with diabetes had higher levels of cytoadhesive molecules (sICAM-1 and sVCAM-1, p<0.001), adiponectin (p<0.001), and haptoglobin (p = 0.023). Their heart rate variability assessment revealed lower standard deviation of beat-to-beat intervals and lower total power (p≤0.019), reflecting autonomous nervous dysfunction. Hemoglobin A1c >8.0% (estimated average blood glucose >10 mmol/L) was associated with higher adiponectin (p<0.001) and obesity was associated with lower adiponectin (p<0.001); thus, obesity damped the effect of hyperglycemia on adiponectin. Obesity was associated with higher sICAM-1 (p≤0.015), tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP), p<0.001. Similarly, high-density lipoprotein (HDL) <1.02 mmol/L was associated with higher sICAM-1, TNFα, IL-6, and hsCRP (p≤0.009) and lower adiponectin (p<0.001). Adiponectin correlated negatively with the inflammatory biomarkers in patients with diabetes.

Conclusion

Subclinical inflammation and endothelial dysfunction are common among young patients with diabetes. Poor diabetes control is associated with higher adiponectin. Obesity and dyslipidemia are associated with lower adiponectin and higher inflammatory and endothelial biomarkers. Intuitively, these predictors of cardiovascular disease are amenable to proper glycemic control, nutritional choices, and regular exercise.

Plasma E-selectin levels can play a role in the development of diabetic retinopathy

PURPOSE

Diabetic retinopathy is one of the leading causes of blindness. There are several risk factors, such as the duration of diabetes or glycemic control of the patient; however, several biochemical factors also alter the process. Our aim was to investigate the role of soluble E-selectin in the formation of diabetic retinopathy.

PATIENTS AND METHODS

Fifty-seven patients (37 female and 20 male, aged 61.71 ± 12.31 years) and 14 healthy control subjects (ten female and four male, aged 63.06 ± 10.46 years) were enrolled in the study. We measured the soluble E-selectin level in the plasma of patients by ELISA. All patients underwent careful ophthalmological examination, including ophthalmoscopy and color fundus photography, while diabetic retinopathy grading was performed in line with the 2012 classification of the American Academy of Ophthalmology (AAO).

RESULTS

The soluble E-selectin level was significantly higher in patients with diabetes compared to controls (32.95 ng/ml vs. 26.55 ng/ml, p = 0.03). Dividing patients into groups by the presence of retinopathy, the E-selectin level was also significantly higher in the retinopathy group (p < 0.05). When we examined diabetic patients by the severity of retinopathy (groups A, B, and C, by the guidelines of the AAO), however, we did not find any significant difference in soluble E-selectin levels, although it tended to be higher in group B.

CONCLUSIONS

An elevated E-selectin level can play a role in the development of diabetic retinopathy, but it does not seem to alter disease severity. However, glycemic control and the reduction of cardiovascular risk factors may also alter the level of E-selectin that might play a role in the prevention of diabetic retinopathy.

Cardiovascular efficacy of sitagliptin in patients with diabetes at high risk of cardiovascular disease: a 12-month follow-up

BACKGROUND

Gliptins should have beneficial effects beyond glycemic control, potentially on the pathophysiology of cardiovascular (CV) diseases, with some basic studies demonstrating this possibility. However, we are yet to answer whether there are any direct CV effects in the clinical setting. We aimed to examine the beneficial effects of sitagliptin in Japanese patients with diabetes and high CV risk for 12 months.

METHODS

This was a prospective, multicenter, observational study of 205 patients with type 2 diabetes. All participants had more than one major CV risk factor and were treated with sitagliptin for 12 months. At 3 or 12 months, we examined the effects of treatment on glycemic control, CV function (by electrocardiography, echocardiography, and reactive hyperemia-peripheral arterial tonometry), and CV biomarkers.

RESULTS

Patients were predominantly elderly (68.8 ± 9.9 years) and male (71.5 %) and typically had more than three CV risk factors (79.2 %). Treatment with sitagliptin significantly reduced the hemoglobin A1c (HbA1c) level from 7.09 % ± 0.81 % at baseline to 6.67 % ± 0.69 % at 3 months and 6.68 % ± 0.73 % at 12 months (both P < 0.001). The reduction in HbA1c was also in tandem with the decrease in the level of high-sensitive C-reactive protein throughout the study. Independent of the change in HbA1c, sitagliptin reduced systolic (-7.0 ± 18.9 mmHg) and diastolic blood pressure (-5.1 ± 11.7 mmHg) at 12 months, and this was associated with a decrease in urinary albumin. In contrast, there were no beneficial effects on cardiac and endothelial function or on the levels of serum B-type natriuretic peptide, high-sensitive troponin T, and urinary 8-hydroxy-2'-deoxyguanosine.

CONCLUSIONS

In Japanese patients with diabetes and multiple CV risk factors, sitagliptin showed a decrease in blood pressure associated with an improvement in albuminuria in addition to glycemic control.

TRIAL REGISTRATION

UMIN000005663.