Characterization of upper lamina propria interstitial cells in bladders from patients with neurogenic detrusor overactivity and bladder pain syndrome.
Bottom Line: The ULP IC were characterized ultrastructurally by the presence of actin filaments with densifications, many caveolae and abundant rough endoplasmic reticulum (RER); on immunohistochemistry ULP IC were immunoreactive for α-sma, vimentin, CD10 and podoplanin and categorized as interstitial Cajal-like cells (ICLC).In both groups there was also an increased presence in ULP lymphocytes.Their unique α-sma(+) /desmin(-) /CD34(-) phenotype allows studying this population in various bladder disorders.
Affiliation: KU Leuven, Department of Morphology and Molecular Pathology, Leuven, Belgium. Thomas.Gevaert@uz.kuleuven.ac.beShow MeSH
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Mentions: In bladders from NDO patients ULP IC were still present. However they appeared to be more slender with a broader space in between the cell layers and a less dense intercellular matrix (Fig. 1). Ultrastructurally the IC contained in their cytoplasm less actin filaments (with almost no organization in parallel bundles) and less caveolae in their peripheral membrane compared to those in normal bladders. In the perinuclear area several mitochondria and well-developed rough endoplasmic reticulum cisternae were obvious (Fig. 2). The immunohistochemical phenotype differed slightly: the IC were still vimentin+ but tend to express less α-sma (in line with the ultrastructural data, observed in all NDO bladders) (Fig. 7). Quantification of the reduced number of α-soma+ IC was difficult because the ULP area of IC was significantly enlarged in NDO bladders (Table 3, Fig. 6) (which means that comparison of cell counts/area with normal bladders was problematic). The ULP IC were also still immunoreactive for podoplanin and CD10 and negative for desmin and CD34. A significantly higher amount of CD20+ lymphoid aggregates/HPF compared to control bladders was present in the lamina propria of NDO bladders (Fig. 7, Table 3). The amounts of CD3+ T cells/HPF in the urothelium and in the ULP were not significantly increased compared to controls. A remarkable observation on electron microscopy was the close apposition of lymphocytes to IC in the ULP, lying in the same direction, and thus creating couples of IC and lymphocytes (Fig. 1).
Affiliation: KU Leuven, Department of Morphology and Molecular Pathology, Leuven, Belgium. Thomas.Gevaert@uz.kuleuven.ac.be