We examined whether interstitial cells (ICs) of the human urinary bladder expressed β-adrenoceptor (AR) subtypes, and semiquantitatively compared the staining intensity among urothelium, ICs and detrusor muscles.Methods:
Paraffin sections of the human urinary bladder were obtained from histologically normal areas of formalin-fixed specimens removed for bladder carcinoma. Double-labeling immunohistochemical methods using antibodies against each β-AR subtype and vimentin were performed to identify ICs of the human urinary bladder. The staining intensity of β-ARs was semiquantitatively compared among urothelium, ICs and detrusor muscles. Further, gender-related difference or age-related correlation in the staining intensity of β-ARs was compared in the same cell types.Results:
The expression of β1-, β2-, and β3-AR was observed in vimentin-positive ICs localized in suburothelium, between detrusor muscle bundles, and within these bundles of the human urinary bladder. The rank order of the staining intensity was urothelium > ICs = detrusor muscles in β1-AR, urothelium > ICs > detrusor muscles in β2-AR, whereas its order was ICs = detrusor muscles > urothelium in β3-AR. Except for urothelial β1-AR, there was no gender-related difference in the signal intensity of β-ARs in the urothelium, ICs or detrusor muscles. Age negatively correlated with the signal intensity of all β-AR subtypes.Conclusion:
β-ARs were expressed in vimentin-positive ICs of the human urinary bladder. As for β2- and β3-AR, there was no gender-related difference or age-related correlation in urothelium, ICs and detrusor muscles. In the human urinary bladder, β-ARs expressed in ICs may play a role in bladder physiology.