Cajal cells in ureteropelvic junction obstruction

Aim: Cajal cells were described initially as a neuron like cells in the motor neuronal ends of the peripherally inervated organs. Recently, the number of investigations studying the localization and pathophysiology of Cajal cell?s are increasing. Aim of this study is to investigate the ultrastructural forms and quantitative changes of Cajal cells, which are thought be responsible as a pacemaker in peristaltic activity of the ureter, in ureteropelvic junction obstruction, which is the most common cause of congenital hydronephrosis.Material-Method: Obstructed ureteropelvic junction in 35 cases were compared with nonobstructed 7 cases for cell counts by immunohistochemical analysis after performing c-kit (CD117). In the electron microscopic study, obstructed 7 ureteropelvic junction cases were compared for occurence in ultrastructural changes with nonobstructed 3 cases.Results: Cajal cells, which were immunohistochemically positive for c-kit, were seen adjacent to the muscle layer in a parallel course to the muscle cells. The increase in the cell counts of the control group was statistically significant from the ureteropelvic junction obstructed group (p<0,001). Similarly in electron microscopic study, the number of interstitial were higher in the control group. Thin cytoplasmic processes of these cells, which didn?t have marked basal lamina, were penetrated between muscle cells. Caveolae counts in the cell cytoplasms of the ureteropelvic junction obstructed group were lower than the ones of the control group.Conclusion: The decrease in the number and the changes in the morphological structure of the Cajal cells in ureteropelvic junction obstruction, direct us to think that these cells have a relationship with ureteral peristaltic activity. Determination of the existence and physiologic effects of these cells, which are thought to act as a pacemaker in urinary system, will enable us better understanding of the urinary system and initiate new horizons in the approach for disorders which cause congenital hydronephrosis.Key words: Cajal cells, c-kit, CD117, obstruction, ureteropelvic