Innervation and receptor profiles of the human apocrine (epitrichial) sweat gland: routes for intervention in bromhidrosis

Abstract

Human apocrine (epitrichial) sweat glands secrete in response to local or systemic administration of catecholamines and cholinergic agonists. As the process of secretion in human apocrine glands is not fully understood and no literature detailing the expression of adrenergic, cholinergic and purinergic receptors is available, there is a need to know the receptor types. Such data could provide new approaches for the treatment of axillary bromhidrosis. To investigate the localization of nerve fibres, adrenergic, cholinergic and purinergic receptors in human axillary apocrine sweat glands by immunohistochemistry. Human axillary apocrine sweat glands were investigated by serial sectioning of paraffin wax-embedded skin samples from volunteers. Sections were examined by light microscopy and immunohistochemistry, using antibodies against neurofilament, alpha- and beta-adrenoceptors, P2Y(1), P2Y(2) and P2Y(4) purinoceptors, and M(3) cholinoceptors. Neurofilaments were found near the eccrine but not the apocrine gland. Apocrine glands demonstrated the presence of beta-2 and beta-3 adrenoceptors in the secretory coil of the gland, but not alpha-1, beta-1 or M(3) receptors. Glandular purinergic staining (P2Y(1), P2Y(2) and P2Y(4)) was found in what looked like myoepithelial cells, while P2Y(1) and P2Y(2) staining was found on apical membranes and diffusely throughout secretory cells. Eccrine gland staining acted as internal positive controls. No nerve fibres were found near the apocrine gland, suggesting that any catecholamine influence is through humoral effects and that glands could be influenced by beta-adrenoceptor subtypes and purinoceptors. Blockage of both these types of receptors offers a route to controlling apocrine secretion from axillary glands and reducing the opportunity for the development of bromhidrosis.