title: Alterations of collagen-producing cells in human pituitary adenomas.
abstract: Extracellular matrix (ECM) is essential in tissue physiology and pathologic conditions such as tumorigenesis. ECM affects tumor cell behavior, proliferation, and metastasis. Pituitary adenomas vary in their clinical characteristics, including ECM deposition. However, the mechanism of desmoplasia in pituitary adenoma is not well understood. The present study focused on the principal component of ECM, collagen, and attempted to characterize collagen-producing cells in pituitary adenomas. Specimens of human pituitary adenomas and control pituitary were obtained during surgery. In situ hybridization for collagen I and III and immunohistochemistry for α-smooth muscle actin (a pericyte marker) and cytokeratin (an epithelial cell marker) were performed. The results showed that pericytes were the sole collagen-producing cells in control pituitary, while four types of collagen-producing cells were present in pituitary adenomas: pericytes, myofibroblasts, fibroblasts, and newly characterized "myoepithelial-like cells". Azan staining showed that fibrous matrix deposition varied among pituitary adenomas and that the area of fibrosis was associated with the number and types of collagen-producing cells. These results suggest that changes in the number and type of collagen-producing cells influence ECM arrangement, which may in turn reflect pathologic characteristics in pituitary adenomas.
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Shimotsuke-shi, Tochigi, Japan.
authors.forename: Alimuddin
authors.initials: A
authors.lastname: Tofrizal
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Shimotsuke-shi, Tochigi, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Shimotsuke-shi, Tochigi, Japan. tyashiro@jichi.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yashiro
authors.affiliation: Department of Hypothalamic and Pituitary Surgery, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Tokyo, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Yamada
mesh_terms: D002452:Cell Count; D024042:Collagen Type I / Q000096:biosynthesis*; D000090602:Collagen Type I, alpha 1 Chain; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D010902:Pituitary Gland / Q000378:metabolism* / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology*
chemical_list: D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain
keywords: Collagen; Desmoplasia; Extracellular matrix; Fibrous adenoma; Myoepithelial-like cells; Pituitary adenoma