Hypercapnic Chemosensitivity in Patients with Heart Failure: Relation to Shifts in Type-1 Insulin-Like Growth Factor and Sex Hormone-Binding Globulin Levels

In patients suffering from heart failure (HF), autonomic imbalance develops even at early stages along with derangements of cardiopulmonary reflex control and abnormalities in metabolism of several hormones. In 34 men with stable systolic HF, we investigated hypercapnic chemosensitivity (HCS, liter/min·mm Hg) measured using the rebreathing method and defined as the slope of the regression line relating minute ventilation (VE, liter/min) to end-tidal carbon dioxide concentration (PETCO 2 , mm Hg). Serum levels of testosterone, dehydroepiandrosterone sulfate, type-1 insulin-like growth factor (IGF-1), sex hormone-binding globulin (SHBG), estradiol, and cortisol were measured using immunoassays. We found that there were no associations between HCS and clinical variables, applied therapy, and co-morbidities (all P > 0.2). Augmented HCS was accompanied by the significantly increased serum SHBG (when expressed in nM, r = 0.43, P 0.2). Thus, it may be suggested that the hormone stimuli can noticeably modify the reflex mechanisms in cardiorespiratory control in the clinical setting of cardiovascular pathology.