Mast cell hyperplasia is associated with aldosterone hypersecretion in a subset of aldosterone-producing adenomas.

CONTEXT: Adrenal mast cells can stimulate aldosterone secretion through the local release of serotonin (5-HT) and activation of the 5-HT4 receptor (5-HT4). In aldosterone-producing adenomas (APAs), 5-HT4 receptor is overexpressed and the administration of 5-HT4 receptor agonists to patients with APA increases plasma aldosterone levels. These data and the well-documented role of mast cells in tumorigenesis suggest that mast cells may be involved in the pathophysiology of APA. OBJECTIVE: The study aimed at investigating the occurrence of mast cells in a series of APA tissues and to examine the influence of mast cells on aldosterone secretion. DESIGN: The occurrence of mast cells in APAs was investigated by immunohistochemistry. Mast cell densities were compared with clinical data. The influence of mast cells on aldosterone production was studied by using cultures of human mast cell and adrenocortical cell lines. RESULTS: In APA tissues, the density of mast cells was found to be increased in comparison with normal adrenals. Mast cells were primarily observed in adrenal cortex adjacent to adenomas or in the adenomas themselves, distinguishing two groups of APAs. A subset of adenomas was found to contain a high density of intratumoral mast cells, which was correlated with aldosterone synthase expression and in vivo aldosterone secretory parameters. Administration of conditioned medium from cultures of human mast cell lines to human adrenocortical cells induced a significant increase in aldosterone synthase (CYP11B2) mRNA expression and aldosterone production. CONCLUSION: APA tissues commonly contain numerous mast cells that may influence aldosterone secretion through the local release of regulatory factors.

Adrenal disorders in human immunodeficiency virus (HIV) infected patients.

Human Immunodeficiency Virus (HIV) infection is associated with adrenal disorders, which must not be underestimated. Adrenal morphologic changes are primarily related to opportunistic infections, mostly by cytomegalovirus and mycobacteria, and malignant tumours such as non-Hodgkin's lymphoma and Kaposi's sarcoma. The most frequent biological alteration reported to date is the increases in cortisol concentrations which results from a decrease in cortisol metabolism and hyperactivity of the hypothalamo-pituitary-adrenal axis commonly referred to as pseudo-Cushing's syndrome. These modifications can be a consequence of antiretroviral therapy and do not require any investigation or specific treatment. Conversely, adrenal insufficiency, either iatrogenic or secondary to glandular infiltration by neoplasms or infections, needs long-term substitution with hydrocortisone, but at present occurs more rarely and usually at late stages of disease progression. The impact of HIV infection on the other adrenocortical functions has been less reported in the literature although several studies show low levels of adrenal androgens, especially dehydroepiandrostenedione (DHEA). Impairment in mineralocorticoid function appears occasional and remains a subject of debate.