Immunohistochemical evaluation of Cajal-like cells and Caveolin-1 levels at ureteropelvic junction obstruction.

Objective: To compare c-kit-positive interstitial Cajal-like cells (ICC) and Caveolin-1 protein levels as a pacemaker and signaling molecules, on ureteropelvic junction (UPJ) specimens, between two groups of pediatric patients with and without ureteropelvic junction obstruction (UPJO).

Methods: We evaluated the UPJ specimens of 45 pediatric patients operated between 2005- 2012 retrospectively. Group 1 included 37 patients who underwent dismembered pyeloplasty due to UPJO. Eight patients underwent nephrectomy by the other reasons (renal tumor, trauma etc) and had normal UPJ were accepted as Group 2. The specimens were examined immunohistochemically with CD117 and Caveolin-1 antibody. According to the total number of ICC; 0-5 cells were accepted as a few (1), 610 cells as moderate (2), and > 10 as many (3). According to the staining intensity of Caveolin-1 at muscle tissue, a subjective evaluation was performed as; mild staining (1), moderate staining (2) and strong staining (3).

Results: The mean value of ICC distribution was calculated 1.37 ± 0.54 in Group 1 and 2.13 ± 0.64 in Group 2 (p = 0.003), and the median value of ICC distribution was found 1 [1-3] in Group 1 and 2 [1-3] in Group 2 (p = 0.008). Median values for the intensity of staining with Caveolin-1 were found 2 [1-3] in the Group 1, and 2.5 [2-3] in the Group 2 (p = 0.025).

Conclusions: A decrease in ICC and Caveolin-1 levels support that there may be a relationship between ICC and Caveolin-1 for UPJO associated with signal transduction and peristalsis in urinary system.