title: Suburothelial interstitial cells.
abstract: The suburothelium has received renewed interest because of its role in sensing bladder fullness. Various studies evaluated suburothelial myofibroblasts (MFs), interstitial cells (ICs), interstitial Cajal cells (ICCs) or telocytes (TCs), which resulted in inconsistencies in terminology and difficulties in understanding the suburothelial structure. In order to elucidate these issues, the use of electron microscopy seems to be an ideal choice. It was hypothesized that the cell population of the suburothelial band is heterogeneous in an attempt to clarify the above-mentioned inconsistencies. The suburothelial ICs of the bladder were evaluated by immunohistochemistry (IHC) and transmission electron microscopy (TEM). Bladder samples from 6 Wistar rats were used for IHC and TEM studies and human bladder autopsy samples were used for IHC. Desmin labeled only the detrusor muscle, while all the myoid structures of the bladder wall were positive for α-smooth muscle actin (SMA). A distinctive α-SMA-positive suburothelial layer was identified. A layered structure of the immediate suburothelial band was detected using TEM: (1) the inner suburothelial layer consisted of fibroblasts equipped for matrix synthesis; (2) the middle suburothelial layer consisted of smooth muscle cells (SMCs) and myoid ICCs, and (3) the outer suburothelial layer consisted of ICs with TC morphology, building a distinctive network. In conclusion, the suburothelial layer consists of distinctive types of ICs but not MFs. The myoid layer, with SMCs and ICCs, which could be considered identical to the α-SMA-positive cells in the suburothelial band, seems the best-equipped layer for pacemaking and signaling. Noteworthy, the network of ICs also seems suitable for stromal signaling.
authors.affiliation: MEDCENTER - Center of Excellence in Laboratory Medicine and Pathology, Bucharest, Romania.
authors.forename: Mugurel Constantin
authors.initials: MC
authors.lastname: Rusu
authors.forename: Roxana
authors.initials: R
authors.lastname: Folescu
authors.forename: Vasile Sorin
authors.initials: VS
authors.lastname: Mănoiu
authors.forename: Andreea Cristiana
authors.initials: AC
authors.lastname: Didilescu
mesh_terms: D000199:Actins / Q000378:metabolism*; D000368:Aged; D000818:Animals; D002102:Cadaver; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D056885:Interstitial Cells of Cajal / Q000166:cytology* / Q000378:metabolism; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D051381:Rats; D017208:Rats, Wistar; D001743:Urinary Bladder / Q000166:cytology* / Q000378:metabolism
chemical_list: D000199:Actins