Effects of GLP-1 receptor agonists on myokine levels and pro-inflammatory cytokines in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

To evaluate the change in circulating serum irisin and interleukin-6 (IL-6), in patients with type 2 diabetes mellitus (T2DM) after 6 and 12 months of GLP-1 treatment.

METHODS AND RESULTS

Eighty-five patients with T2DM inadequately controlled with insulin or other hypoglycaemic drugs were added to dulaglutide (N° = 44) and liraglutide (N° = 41) treatment. After 6 months of GLP-1 analogues a significant decrease in BMI (p < 0.001), waist circumference (WC) (p < 0.001), fasting blood glucose (p < 0.001), HbA1c (p < 0.001), total cholesterol (p < 0.001), LDL-cholesterol (p = 0.003), triglycerides (p = 0.017), IL-6 (p = 0.045) and a significant increase in serum irisin (p < 0.001) were observed compared to baseline. After 12 months of treatment no significant differences were found compared to the levels at 6 months. The change in irisin from baseline (Δ_irisin) was significantly related to the changes in total-cholesterol (Δ_total-cholesterol) (r = -0.293; p = 0.020), while the change in IL-6 (Δ_IL-6) was significantly related to the changes in WC (Δ_WC) (r = 0.347; p = 0.006).

CONCLUSIONS

Additive treatment with GLP1-analogues results in an increase in serum circulating irisin levels and a decrease in IL-6. The post-treatment change in irisin was correlated with a decrease in total cholesterol, while the change in IL-6 was correlated with a decrease in WC.

High-density lipoprotein cholesterol affects early endothelial progenitor cell number and endothelial function in obese women

OBJECTIVE

In order to improve our understanding of high-density lipoprotein cholesterol (HDL-C) cardiovascular (CV) impact in obesity, the association of HDL-C plasma level with circulating early endothelial progenitor cell (early-EPC) number and endothelium-dependent vasodilatation (EDV) in obese women with normal or high low-density lipoprotein cholesterol (LDL-C) plasma levels was evaluated.

DESIGN AND METHODS

One hundred thirteen obese female subjects and a control group of 78 healthy female subjects were recruited. Circulating early-EPC were assessed by single- and two-color flow cytometric analyses with a fluorescence activated cell sorting (FACScan) flow cytometer. EDV was evaluated as response to ischemia by strain gauge plethysmography.

RESULTS

Both early-EPC number and EDV were significantly decreased in obese women compared with the control group. Obese women with low HDL-C showed a further decrease of early-EPC and EDV in the presence of both high or normal LDL-C plasmatic levels. In the normal HDL-C level subgroup, hypercholesterolemic and nonhypercholesterolemic subjects showed no difference in early-EPC number, whereas slight EDV impairment was present in hypercholesterolemic subjects.

CONCLUSION

In obese women, low HDL-C is associated to decreased early-EPC number and impaired EDV, suggesting the need to assess whether evaluation of early-EPC and EDV may increase HDL-C prognostic value in the stratification of CV risk.

Ghrelin induces proliferation in human aortic endothelial cells via ERK1/2 and PI3K/Akt activation

The direct ghrelin (Ghr) involvement in cardiovascular (CV) system homeostasis has been suggested by the expression of its receptor in CV tissues and by evidence that ghrelin mediates CV activities in animals and in humans. Moreover, low Ghr plasma levels have been reported in pathological conditions characterized by high cardiovascular risk. In the present study, we investigated Ghr effect on proliferation of human aortic endothelial cell (HAEC) and involved transduction pathways. Our results indicate that ghrelin elicited proliferation in a dose-dependent manner (EC(50) about of 5nmol/L) in cultured HAEC, and that this effect was inhibited by the receptor antagonist (D-Lys3)-GHRP-6. Western blot experiments documented an activation of external receptor activated kinases (ERK1/2) and Akt in a dose-dependent fashion, as well as involvement of the cAMP pathway in ERK1/2 phosphorylation. Experiments conducted with appropriate pharmacological inhibitors to investigate Ghr-induced HAEC proliferation confirmed the involvement of ERK1/2 and I3P/Akt pathways, as well as the role of AMP cyclase/PKA pathway in ERK1/2 phosphorylation. Our results indicate that Ghr promotes HAEC proliferation, and thus may be a protective factor against vascular damage. The low ghrelin serum levels reported in insulin-resistant states may not be able to effectively counteract endothelial cell injury.