Study investigates adrenal function associated with rheumatic syndromes

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) have been identified as two closely related syndromes almost exclusively affecting people over 50 years old. The authors note that despite the close association with age, the pathogenic mechanisms that could explain this age-related predisposition are unknown. They add that aging is accompanied by a number of changes in the endocrine system that may predispose pathological conditions to occur in the elderly. As a result of these observations, the researchers explored the hypothalamic-pituitary-adrenal axis and its relationship to GCA and PMR. Basal levels of adrenal hormones as well as the response to low-dose adrenocorticotropin hormone (ACTH) were investigated in 20 patients (16 GCA and 4 PMR) with active untreated disease and compared with levels in 16 healthy age-matched controls.It was reported that male patients with active disease had low basal levels of androstenedione compared to the controls (2.1 ± 0.4 v 1.1 ± 8.8 nmol/L in male PMR/GCA patients, p=0.01). Furthermore, cortisol and dehydroepiandrosterone reached higher levels in patients than in healthy subjects after challenge with low-dose ACTH. The researchers note this observation to indicate that the adrenal gland function was not suppressed. In addition, the authors did not find a clear relationship between the levels of acute phase reactants and adrenal hormones in the patient population.In their discussion the authors comment that it is well known that the immune and endocrine systems are closely linked and that this may, in part, explain why elderly individuals show increased susceptibility to autoimmune processes. They describe their findings to be more compatible with the hypothesis that the abnormalities found in the patient group are the consequences of chronic illness rather than a crucial factor contributing to the pathogenesis of the disease.Reference...