Altered Hypothalamic-Pituitary-Adrenal Axis Activity in Patients with Chronic Heart Failure

Abstract

Neuroendocrine factors play an important role in the pathogenesis of chronic heart failure. Despite numerous clinical and experimental studies, the role of the hypothalamic-pituitary-adrenal axis and glucocorticoid hormones is not fully characterised. Here we present a study of plasma cortisol concentration in 74 chronic heart failure patients, divided into four groups based on NYHA functional classes I-IV, and in 17 control subjects. In parallel, we performed morphological analysis of the hypothalamic-pituitary-adrenal axis components from 8 male patients who had died from chronic heart failure, and 9 male controls. In our study we applied immunohistochemical method and quantitative analysis to investigate an expression of hypothalamic neurohormones (corticotropin-releasing hormone, vasopressin) and adrenocorticotropin hormone in the pituitary, as well as performed general histological examination of the adrenal cortex. Measurement of morning cortisol concentration in plasma of chronic heart failure patients revealed neither difference compared to controls nor with the severity of the disease. Despite this, a two-fold increase in the density of corticotropin-releasing hormone-immunoreactive neurons as well as a two-fold increase in the number of corticotropin-releasing hormone neurons co-expressing vasopressin in the hypothalamic paraventricular nucleus were found. In the anterior pituitary the density of adrenocorticotropin hormone-immunoreactive cells was significantly increased. General histological analysis of the adrenal cortex revealed a drastic thinning of the zona fasciculata and dystrophic changes in corticocytes. Structural changes, observed in the adrenal cortex, suggest a relative glucocorticoid deficiency, which may contribute to corticotropin-releasing hormone and adrenocorticotropin hormone upregulation in hypothalamus and pituitary of chronic heart failure patients.