Brief periods of transcutaneous auricular vagus nerve stimulation improve autonomic balance and alter circulating monocytes and endothelial cells in patients with metabolic syndrome: a pilot study

BACKGROUND

There is emerging evidence that the nervous system regulates immune and metabolic alterations mediating Metabolic syndrome (MetS) pathogenesis via the vagus nerve. This study evaluated the effects of transcutaneous auricular vagus nerve stimulation (TAVNS) on key cardiovascular and inflammatory components of MetS.

METHODS

We conducted an open label, randomized (2:1), two-arm, parallel-group controlled trial in MetS patients. Subjects in the treatment group (n = 20) received 30 min of TAVNS with a NEMOS® device placed on the cymba conchae of the left ear, once weekly. Patients in the control group (n = 10) received no stimulation. Hemodynamic, heart rate variability (HRV), biochemical parameters, and monocytes, progenitor endothelial cells, circulating endothelial cells, and endothelial micro particles were evaluated at randomization, after the first TAVNS treatment, and again after 8 weeks of follow-up.

RESULTS

An improvement in sympathovagal balance (HRV analysis) was observed after the first TAVNS session. Only patients treated with TAVNS for 8 weeks had a significant decrease in office BP and HR, a further improvement in sympathovagal balance, with a shift of circulating monocytes towards an anti-inflammatory phenotype and endothelial cells to a reparative vascular profile.

CONCLUSION

These results are of interest for further study of TAVNS as treatment of MetS.

Cholinergic stimulation with pyridostigmine modulates a heart-spleen axis after acute myocardial infarction in spontaneous hypertensive rats

The mechanisms regulating immune cells recruitment into the heart during healing after an acute myocardial infarction (AMI) have major clinical implications. We investigated whether cholinergic stimulation with pyridostigmine, a cholinesterase inhibitor, modulates heart and spleen immune responses and cardiac remodeling after AMI in spontaneous hypertensive rats (SHRs). Male adult SHRs underwent sham surgery or ligation of the left coronary artery and were randomly allocated to remain untreated or to pyridostigmine treatment (40 mg/kg once a day by gavage). Blood pressure and heart rate variability were determined, and echocardiography was performed at day six after MI. The heart and spleen were processed for immunohistochemistry cellular analyses (CD3⁺ and CD4⁺ lymphocytes, and CD68⁺ and CD206⁺ macrophages), and TNF levels were determined at day seven after MI. Pyridostigmine treatment increased the parasympathetic tone and T CD4⁺ lymphocytes in the myocardium, but lowered M1/M2 macrophage ratio towards an anti-inflammatory profile that was associated with decreased TNF levels in the heart and spleen. Treatment with this cholinergic agent improved heart remodeling manifested by lower ventricular diameters and better functional parameters. In summary, cholinergic stimulation by pyridostigmine enhances the parasympathetic tone and induces anti-inflammatory responses in the heart and spleen fostering cardiac recovery after AMI in SHRs.

Effects of a combined oral contraceptive containing 20 mcg of ethinylestradiol and 3 mg of drospirenone on the blood pressure, renin-angiotensin-aldosterone system, insulin resistance, and androgenic profile of healthy young women

Combined oral contraceptives (COCs) may increase the risk for cardiovascular disease depending on the ethynyl estradiol (EE) dose and the androgenicity of the progestogens. Our objective was to evaluate the impact of a COC containing 20 mcg EE + 3 mg drospirenone on blood pressure (BP), renin-angiotensin-aldosterone system, insulin resistance, and androgenic profile of healthy young women. Eighty-one healthy young women aged 30 ± 1 years (case group, n = 49, received COC; control group, n = 32, used no COC) were assessed twice, before and after the 6-month study. Statistical analysis employed the paired t-tests and expressed the data in mean and standard deviation. Results were as follows: no changes in BP or in BMI; a significant increase in aldosterone, plasma renin activity, triglycerides, and total cholesterol levels, but a non-significant increase in HDL and no significant changes in LDL levels (these parameters remained within normal ranges); a significant increase in the HOMA-IR index and a significant decrease in dehydroepiandrosterone sulfate (SDHEA), androstenedione, total testosterone, and free testosterone levels; no significant variations in the control group parameters. An oral contraceptive combination of a low EE dose and an anti-androgenic progestogen does not negatively influence the risk factors for a cardiovascular disease.