Journal of Cellular and Molecular Medicine vol:15 issue:12 pages:2586-2593
Introduction The upper lamina propria (ULP) area of interstitial cells (IC) in bladder has been studied for more than a decade in several species including humans. Nevertheless there is still lack of uniformity in terminology of this cell layer. The aim of the present study was to add new data to the morphological and immunohistochemical phenotype of these cells and to find out whether this phenotype is changed in bladders from patients with neurogenic detrusor overactivity (NDO) and bladder pain syndrome (BPS). Methods Bladder tissue was obtained from a control group and from patients with NDO and BPS. Samples were processed for morphology, electron microscopy and immunohistochemistry. A morphological and immunohistochemical phenotype for the ULP IC was assessed and changes in this phenotype were looked for in samples from patients with NDO and BPS. Results The ULP IC were characterized ultrastructurally by the presence of actin filaments with densifications, many caveolae and abundant RER; on immunohistochemistry ULP IC were immunoreactive for alpha-sma, vimentin, CD10 and podoplanin and categorized as interstitial Cajal-like cells (ICLC). In NDO and BPS bladders we found a phenotypical shift towards a fibroblastic phenotype which was even more pronounced in the NDO group. In both groups there was also an increased presence in ULP lymphocytes. Conclusion The ULP area in the human bladder contains a population of ICLC with distinct ultrastructural morphology and immunohistochemical phenotype. Their unique alpha-sma+/desmin-/CD34- phenotype allows to study this population in various bladder disorders. In bladders form patients with BPS and NDO, we observed these ULP ICLC to shift towards a fibroblast-phenotype.