title: Immunolocalization of aquaporin-5 in normal human skin and hypohidrotic skin diseases.
abstract: Aquaporin (AQP)-5 has been shown to be expressed in the secretory parts of mouse, rat and horse sweat glands. However, the precise localization of AQP-5 in normal and diseased human skin has not been fully determined. The aim of the present study was to further clarify the immunolocalization of AQP-5 in normal human skin and hypohidrotic skin diseases. Normal human scalp skin and biopsies from skin affected by hypohidrotic diseases were analyzed for AQP-5 and/or dermcidin expression by immunohistochemistry, immunofluorescence and/or immunoelectronmicroscopy. AQP-5 was expressed on the apical and basolateral plasma membranes of the clear cells in eccrine sweat coils, but not in ductal components or apocrine glands. Numbers of AQP-5-positive coils in the secretory part of eccrine sweat glands were decreased in Sjögren's syndrome, but not in skin affected by idiopathic segmental anhidrosis or idiopathic pure sudomotor failure. AQP-5 was mostly localized to the plasma membranes of clear cells in the secretory coils of eccrine sweat glands, suggesting that it plays a role in producing the primary sweat fluid.
authors.affiliation: Division of Dermatology, Fujigaoka Hospital, Showa University School of Medicine, Yokohama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iizuka
authors.forename: Takao
authors.initials: T
authors.lastname: Suzuki
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Nakano
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Sueki
mesh_terms: D051402:Aquaporin 5 / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004439:Eccrine Glands / Q000033:anatomy & histology / Q000378:metabolism; D006801:Humans; D007007:Hypohidrosis / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D010455:Peptides / Q000378:metabolism; D012859:Sjogren's Syndrome / Q000378:metabolism / Q000473:pathology; D012867:Skin / Q000033:anatomy & histology / Q000378:metabolism*
chemical_list: C496036:AQP5 protein, human; D051402:Aquaporin 5; D010455:Peptides; C442243:dermcidin