Decreased plasma myonectin levels in female patients with type 2 diabetes mellitus and its correlation with lipid and glycemic parameters

OBJECTIVE

Myonectin is a novel myokine which has significant implications on diabetes. This study aimed to investigate plasma myonectin levels in patients with type 2 diabetes mellitus (T2DM), and their correlation with body composition, lipid and glycemic parameters.

PATIENTS AND METHODS

The study participants included 40 diabetic and 33 non-diabetic healthy adult Saudi females matched for their BMI and age. Body composition was assessed by bioelectrical impedance analysis. Fasting blood samples were used to investigate plasma myonectin levels by ELISA, along with lipid and glycemic parameters.

RESULTS

We found that plasma myonectin levels were significantly decreased in diabetic patients (40.90±4.13 ng/ml, p<0.05) compared to non-diabetic participants (59.58±4.41). Diabetic patients with poor glycemic parameters had significantly decreased myonectin levels (35.18±4.03 ng/ml p<0.05) compared to non-diabetic healthy subjects. There was no significant difference in myonectin levels between diabetic patients with good glycemic control (55.76±8.09 ng/ml p>0.05) and non-diabetic healthy participants. Pearson correlation analysis indicated a significant negative correlation with fasting blood sugar (R=-0.366, p=0.001), HbA1c (R=-0.406, p<0.0001), triglycerides (R=-0.264, p=0.024), insulin (R=-0.278, p=0.017), and HOMA-IR (R=-0.409, p<0.0001).

CONCLUSIONS

Our findings highlight an important aspect of myonectin in the pathophysiology of T2DM. They also show that myonectin has the potential to be a useful biomarker and therapeutic target in T2DM.

Serum inducible and endothelial nitric oxide synthase in coronary artery disease patients with Type 2 Diabetes mellitus

OBJECTIVE

Coronary artery disease (CAD) is a well-known cause of morbidity and mortality in type 2 diabetes mellitus (T2DM). The role of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) in T2DM patients in relation to CAD is not well understood. We examined serum inducible and endothelial nitric oxide synthase activities in patients with T2DM in relation to the presence of coronary artery disease.

PATIENTS AND METHODS

The present study was conducted in the Department of Physiology, King Saud University, Riyadh, Saudi Arabia. Subjects were grouped into control (Group A, n=87), T2DM without CAD (Group B, n=70), and T2DM patients with CAD (Group C, n=49). The selection of T2DM subjects was according to the American Diabetes Association (ADA). Serum iNOS, eNOS, hsCRP, nitrates and nitrites along with lipid profile were compared between different groups. Spearman's correlation and ROC analysis were also performed.

RESULTS

Serum eNOS levels were significantly high in the control group (112.38±47.16 U/ml) than in DM without CAD (81.43±49.91 U/ml) and DM with CAD (84.80±43.32 U/ml, p<.001). Serum iNOS levels were significantly higher in DM with CAD (42.87±28.83 U/ml) compared to both control (22.08±11.77 U/ml) and DM without CAD (16.24±12.30 U/ml, p<.001). Additionally, the differences in nitrite and NO were not significant between the three groups (34.06±24.75, 33.02±21.50, 38.83±24.34 uM, p = .384), and (56.51±36.78, 49.89±28.83 vs. 55.77±30.34 uM, p=.416) respectively. ROC curve analysis revealed a sensitivity and specificity of 73.5% and 68.6% of iNOS level at a cutoff point of 21.1 U/ml to predict CAD in T2DM patients. The ROC analysis for iNOS, eNOS, and hs-CRP were .782 (p<.001), .574 (p=.170), and .726 (p<.001), respectively.

CONCLUSIONS

Patients with T2DM have significantly higher levels of serum iNOS and lower levels of eNOS. However, iNOS levels were significantly higher in T2DM patients with concomitant CAD. Moreover, iNOS activity positively correlated with glycemic control and hsCRP. Therefore, iNOS could be an emerging future marker for CAD in T2DM patients and its antagonists could be useful in the management of these patients.

The effects of calorie restriction on aging: a brief review

Calorie restriction (CR) without malnutrition slows aging and increase average and maximal lifespan in model organisms and rodents. In human and non-human primates, CR has beneficial effects on human longevity and reduces the incidence of age-related diseases such as obesity, diabetes mellitus hypertension, cardiovascular disease and cancer. CR exerts its anti-aging effects through different mechanisms including small noncoding RNA molecules (sncRNAs), the composition of diet and IGF-1 signaling. The aim of this review was to discuss recent developments to understand the consequences and mechanisms of CR on longevity.