Interplay between circulating nitric oxide and interleukin-17 in elderly outpatients with non-inflammatory conditions

Nitric oxide (NOx) availability in biological systems is associated with either favorable or unfavorable outcomes. In this sense, several studies bring about evidence that unbalanced NOx production may be underlying to the pathophysiology of vascular disorders. Our study investigated the possible association of clinical, biochemical and inflammatory variables with total circulating levels of NOx in elderly patients devoid of major inflammatory conditions. Clinical (demographics, lifestyle, anthropometry, pressoric traits) and biochemical characteristics (lipemic, glycemic and hormonal profiles) were assessed from 168 geriatrics outpatients eligible for primary care for age-related disorders. Furthermore, circulating levels of 10 inflammatory mediators and of NOx were measured. Correlation tests analyzed categorical or continuous traits according to serum NOx and found no association between NOx and any of the clinical or laboratory data but a negative correlation between plasma NOx concentrations and levels of the immune mediator IL17a (r = -0.236; P = 0.004). Evidence for a correlation between circulating NOx and IL17 is already present in the literature, mostly from studies conducted under inflammatory conditions. Our hypothesis is that such negative correlation can be attributed to an endogenous homeostatic system that IL17 production by the constitutively produced NOx from the vascular endothelium.