Immunohistochemical and electron microscopic examination of Cajal cells in ureteropelvic junction obstruction

Evaluation of Interstitial Cells of Cajal-Like Cells at the Pelviureteric Junction in Children with Pelviureteric Junction Obstruction: A Prospective Study and Review of Literature

INTRODUCTION

The etiopathogenesis of pelviureteric junction obstruction (PUJO) has been debated. Recently, the role of interstitial cells of Cajal-like cells (ICC-LC)has been studied and reported to be the cause of this functional obstruction. We studied the histopathology and ICC-LC density at PUJ and compared it with that of PUJ of the control group and distal ureteric margin of the study group.

METHODS

A prospective study was conducted which included PUJO patients in the study group and the renal tumor patients in the control group. Histopathological examination (muscle hypertrophy and fibrosis) and immunohistochemistry (ICC-LC density) were done. The muscle hypertrophy, fibrosis, and ICC-LC density at the PUJ in both the groups were compared. A similar comparison was performed between the findings at the PUJ and the distal margin in the study group.

RESULTS

The study and control groups included 37 PUJO patients and 13 Wilms tumor patients. The ICC-LC density at PUJ in the study group was significantly lower than that in the control group (P < 0.001) and that at the distal resected margin of the study group (P < 0.001). Significantly increased muscle hypertrophy (P < 0.001) and fibrosis (P = 0.002) were seen at PUJ in the study group compared to the control group. No significant association was noted between the ICC-LC density and muscle hypertrophy at PUJ and the distal resected margin in the study group.

CONCLUSION

A significant decrease in the density of ICC-LC and increased fibrosis and muscle hypertrophy at PUJ in children with PUJO play a role in the etiopathogenesis of the disease.

Variations in the Density and Distribution of Cajal Like Cells Associated With the Pathogenesis of Ureteropelvic Junction Obstruction: A Systematic Review and Meta-Analysis

Introduction: Cajal like cells (CLCs) in the upper urinary tract have an ability to generate coordinated spontaneous action potentials and are hypothesized to help propel urine from renal pelvis into the ureter. The objective of this review was to describe the variations in the density and distribution of CLCs associated with ureteropelvic junction obstruction (UPJO). Materials and Methods: Studies comparing the density and distribution of CLCs in the human upper urinary tract in patients with UPJO and healthy controls were included in this systematic review. We searched online electronic databases; Ovid MEDLINE, Scopus, PubMed and Cochrane reviews for the studies published before October 31, 2020. A meta-analysis was conducted to compare the density of CLCs at the ureteropelvic junction (UPJ) in patients with UPJO and matched controls. Results: We included 20 and seven studies in the qualitative and quantitative synthesis, respectively. In majority (55%) CLCs were located between the muscle layers of the upper urinary tract. The CLC density in the UPJ gradually increased with aging in both healthy subjects and patients with UPJO. The pooled analysis revealed that the density of CLCs at the UPJ was significantly low in patients with UPJO compared to the controls (SMD = -3.00, 95% CI = -3.89 to -2.11, p < 0.01). Conclusions: The reduction in CLC density at the UPJ in patients with UPJO suggests a contribution from CLCs in the pathogenesis of UPJO. Since age positively correlates with CLC density, it is imperative to carefully match age when conducting case control studies comparing the CLC density and distribution. Protocol Registration Number: CRD42020219882.

Comparison of different pathological markers in predicting pyeloplasty outcomes in children

PURPOSE

To compare the efficacy of pathological markers like Interstitial cells of Cajal (ICC), neurons and Collagen to Muscle ratio (CM ratio), in predicting pyeloplasty outcomes.

METHODS

Histological sections from 31 patients with UPJO were analyzed for ICC & neurons on immuno-histochemistry and CM ratio on Masson's trichrome staining. Post-operative outcomes were analyzed at 1-year follow up; expressed as excellent, moderate or mild improvement, static and deterioration based on the three factors: ultrasound grade, differential renal function and renogram drainage pattern. The pathological findings were correlated with clinical outcomes.

RESULTS

The study group (n = 31) had a mean age 2.9 (0.6) years (M: F = 22:9). UPJ segment had significantly less ICC/neurons and more collagen compared to normal ureter (p = 0.001). Pathological parameters at the anastomosed end of ureter had a better correlation than those at UPJ with clinical outcome. CM ratio with a stronger correlation (r = - 0.94; p = 0.001) was a better predictor of prognosis than ICC (r = 0.76; p = 0.01) or neuron (r = 0.83; p = 0.01) density. ICC >10/HPF, neurons >6/HPF and CM ratio <1.2 at ureteric end anastomosed were predictors of success.

CONCLUSIONS

CM ratio analysis at anastomosed ureter is a superior marker for predicting pyeloplasty outcomes.

LEVEL OF EVIDENCE

Type 2: Development of diagnostic criteria in a consecutive series of patients.

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.

Immunohistochemistry in Ureteropelvic Junction Obstruction and Its Correlation to Postoperative Outcome

Aim:

To investigate the correlation between the status of interstitial cells of Cajal (ICC) in ureteropelvic junction (UPJ) and the resected ureteric margin and the postoperative outcome of Anderson-Hynes pyeloplasty in UPJ obstruction (UPJO) and to compare the ICC in the UPJ and the resected margin of the normal ureter.

Materials and Methods:

An observational study was conducted over a period of 2 years at the Department of Pediatric Surgery at Niloufer Institute of Women and Child Health. Children with intrinsic UPJO who underwent Anderson-Hynes dismembered pyeloplasty were included in the study. Six months postoperatively, the patients were divided into two groups based on diuretic isotopic renogram using technetium-99m-labeled diethylene triaminepentaacetic acid. Group 1 comprised patients with good surgical outcome. Group 2 comprised patients with a poor outcome. The histologic specimens were evaluated for ICC, and the immunohistochemical findings were correlated with the outcome.

Results:

Twenty-five patients were included in this study (19 male and 6 female). Seventy-six percent of patients were under the age of 1 year. Group 1 had 23 cases and Group 2 had 2 cases. Out of the two patients with a poor outcome, one had negative grading at the UPJ and one had positive grading. Both these patients had a negative grading at the lower resected margins. More number of patients (24%) had +++ grading at the lower resected margin when compared to the UPJ (8%).

Conclusion:

This is the first study which correlates the status of ICC in UPJ with the outcome of pyeloplasty in pediatric patients. Both the cases with bad outcome had no ICC at the lower margin of the resected specimen and one case had no ICC at the UPJ. There is a statistically significant difference (P = 0.001) in the number of ICC at the UPJ and the resected margin.

Calcium signalling in Cajal-like interstitial cells of the lower urinary tract

Interstitial cells of Cajal (ICC) serve several critical physiological roles in visceral smooth muscle organs, including acting as electrical pacemakers to modulate phasic contractile activity and as intermediaries in motor neurotransmission. The major roles of ICC have been described in the gastrointestinal tract, however, ICC-like cells (ICC-LC) can also be found in other visceral organs, including those of the lower urinary tract (LUT), where they provide similar functions, acting as electrical pacemakers and as intermediary cells involved in the modulation of neurotransmission to adjacent smooth muscle cells. The physiological functions of ICC-LC, in particular their role as pacemakers, relies on their ability to generate transient and propagating intracellular Ca(2+) events. The role of ICC-LC as pacemakers and neuromodulators in the LUT is increasingly apparent and the study of their intracellular Ca(2+) dynamics will provide a better understanding of their role in LUT excitability.