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Published on: December 1, 2017
C-Kit receptor (CD117) in the porcine urinary tract
Roman Metzger1, Anja Neugebauer, Udo Rolle
1Department of Pediatric Surgery, University of Leipzig, Leipzig, Germany. roman.metzger@medizin.uni-leipzig.de
Insights
C-Kit positive interstitial cells (IC) are widely distributed throughout the porcine urinary tract, suggesting a role in regulating smooth muscle function. These cells, along with interepithelial cells, may contribute to intrinsic pacemaker activity and urothelial regeneration.
Area of Science:
- Urology
- Gastroenterology
- Cell Biology
Background:
- C-Kit positive interstitial cells of Cajal (ICC) are crucial for smooth muscle motility in luminal organs.
- Previous research indicated the presence of c-Kit (CD117)-positive interstitial cells (IC) in the genitourinary tract, but systematic distribution studies were lacking.
Purpose of the Study:
- To systematically analyze the localization and distribution of the c-Kit receptor in the porcine urinary tract.
- To investigate the potential role of these cells in urinary tract function.
Main Methods:
- Immunohistochemistry (APAAP, IF) using multiple CD117 antibodies on porcine urinary tract tissues.
- Whole mount preparations with confocal fluorescence microscopy and 3D reconstruction.
- UV-laser microdissection and RT-PCR for molecular confirmation.
Main Results:
- CD117-immunoreactivity identified bipolar IC and mast cells (MC) throughout all layers (adventitia, tunica muscularis, submucosa) of the porcine urinary tract.
- Whole mounts revealed IC in close apposition to smooth muscle bundles and veins, with some CD117-positive cells found within the urothelium.
- The highest density of IC was observed at the ureteropelvic junction, though differences across segments were minimal.
Conclusions:
- The ubiquitous distribution and close association of IC with smooth muscle suggest their contribution to intrinsic pacemaker activity in the porcine urinary tract.
- Interepithelial CD117-positive cells may function as mechanosensors or play a role in urothelial regeneration.
Abstract:
C-Kit positive interstitial cells of Cajal (ICC) play an important role in the regulation of the smooth muscle motility, acting as internal pacemakers to provide the slow wave activity within various luminal organs. Recently c-Kit-(CD117)-positive interstitial cells (IC) have been shown in the genitourinary tract, but systematic studies on the distribution and density of IC within the urinary tract are still lacking. Therefore the aim of the present study was to analyze systematically the localization and distribution of the c-Kit receptor in the urinary tract of the pig using immunohistochemical and molecular methods. Tissue samples were harvested from the porcine urinary tract including renal calices and pelvis, ureteropelvic junction, proximal, middle and distal ureter, ureteral orifice, fundus, and corpus of the bladder and the internal urethral orifice. Small and large intestine specimen served as controls. Immunohistochemistry (APAAP, IF) was applied on serial frozen sections using four monoclonal and polyclonal antibodies recognizing CD117. Whole mounts of the porcine upper urinary tract were prepared and investigated using conventional and confocal fluorescence microscopy followed by three-dimensional reconstruction. UV-laser microdissection and RT-PCR were applied to confirm the immunohistochemical results. CD117-immunoreactivity labeled bipolar IC and round-shaped mast cells (MC) throughout the adventitia, tunica muscularis and submucosa within the whole porcine urinary tract. While MC were found continuously in all investigated segments, a gradient of bipolar IC was evident. The whole mount preparations gave a detailed cytomorphology of IC within the various layers of the porcine urinary tract. Whole mount preparations revealed closed apposition of bi- and tripolar c-Kit positive IC parallel to the smooth muscle bundles and to veins of the tunica muscularis and adventitia. In the urothelium single CD117-positive interepithelial cells were found. The highest density of CD117-positive cells was found at the ureteropelvic junction, however the differences in between the segments were minimal. Microdissection and RT-PCR confirmed the results uncovered by immunohistochemistry. The ubiquitous distribution of IC and their close relationship to smooth muscle provides strong evidence that IC could contribute to the intrinsic pacemaker activity within the porcine (upper and lower) urinary tract. The role of the interepithelial CD117-positive cells as mechanosensors or as a precursor cell in the regeneration of the urothelium, is conceivable.
