Influence of Interstitial Cells of Cajal in Congenital Ureteropelvic Junction Obstruction

BACKGROUND: The etiopathogenesis of congenital ureteropelvic junction obstruction (UPJO) has been inconclusive in spite of the numerous studies carried out to find the possible causative factor. The results of different studies have been conflicting and contradictory. It has been postulated that the interstitial cells of Cajal (ICC) are the pacemaker cells located in the ureteropelvic junction (UPJ) and regulate the peristalsis in this region. Paucity of these cells may be one of the causative factors for congenital UPJO although there is no clear consensus on this issue. Therefore, the present study has been carried out to ascertain the role of ICC as one of the possible etiological factors for congenital UPJO. The aim of this study is to first identify the presence of ICC at UPJ, second to compare the average number of ICC in congenital UPJO with a control population without UPJO, and third to ascertain whether any correlation exists between the number of ICC and postoperative improvement in function of the affected kidney. MATERIALS AND METHODS: A total number of 30 patients who underwent dismembered Anderson-Hynes pyeloplasty for congenital UPJO between June 2016 and November 2017, were compared with seven controls who underwent nephroureterectomy for various other reasons. The specimen was subjected to immunohistochemistry (IHC), and a quantitative comparison was made for the ICC between cases and controls. The preoperative and postoperative function was evaluated by renal diuretic scintigraphy. RESULTS: The disease was more common among males in the ratio of 6.5:1, and there was a predominance of the left-sided involvement. In the studied cases, the average number of ICC seen for every high-power field (hpf) was 4.86 ± 0.76/hpf, whereas in control it was 11.74 ± 0.86/hpf (P = 0.04). The postoperative outcome, as measured by the improvement in split renal function, did not have any correlation with the number of ICC. CONCLUSION: The ICC are present at the UPJ and can be detected by immunohistochemistry due to their CD117 positivity. These cells are significantly low at this site in cases of congenital UPJO when compared to controls without any obstruction. The number of ICC bears no correlation to the postoperative improvement in function.