title: Collagen-to-smooth muscle ratio helps prediction of prognosis after pyeloplasty.
abstract: OBJECTIVE
  We quantitatively evaluated the collagen-to-smooth muscle tissue matrix ratio in ureteropelvic junction obstruction, and compared the ratio with the degree of obstruction, patient age and postoperative renal recovery.
  
  
  METHODS
  We analyzed histological sections from 65 patients with ureteropelvic junction obstruction and 6 normal controls. Morphological and functional grading systems were adapted to determine the degree of renal obstruction. To examine smooth muscle and collagen tissue, sections were stained using Masson's trichrome. Two distinct populations of collagen versus smooth muscle were identified and the tissue matrix ratio was calculated by color image analysis.
  
  
  RESULTS
  The mean tissue matrix ratio plus or minus standard deviation was 1.32+/-0.79 in all patients with ureteropelvic junction obstruction but only 0.30+/-0.10 in normal controls (p <0.0001). It appeared that the lower the tissue matrix ratio, the better the improvement in postoperative hydronephrosis (r = -0.50, p = 0.0001). Better recovery of renal function after pyeloplasty was observed with a decrease in the tissue matrix ratio (r = -0.43, p = 0.0004). We divided patients according to the tissue matrix ratio into groups 1--ratio 1 or less, 2--greater than 1 to 1.5 and 3--greater than 1.5 to determine a more detailed and clinically applicable correlation of tissue matrix ratio with postoperative renal functional changes. Better improvement in postoperative renal function was observed in group 1 than in group 3 (p = 0.002). Also, the tissue matrix ratio increased with patient age (r = 0.33, p = 0.007).
  
  
  CONCLUSIONS
  Since our data represent an objective and quantitative parameter associated with ureteropelvic junction obstruction, we believe that our findings may help to predict the prognosis after pyeloplasty.
authors.affiliation: Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea.
authors.forename: W J
authors.initials: WJ
authors.lastname: Kim
authors.forename: S J
authors.initials: SJ
authors.lastname: Yun
authors.forename: T S
authors.initials: TS
authors.lastname: Lee
authors.forename: C W
authors.initials: CW
authors.lastname: Kim
authors.forename: H M
authors.initials: HM
authors.lastname: Lee
authors.forename: H
authors.initials: H
authors.lastname: Choi
mesh_terms: D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000032:analysis*; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000601:surgery*; D007223:Infant; D007231:Infant, Newborn; D007682:Kidney Pelvis; D008297:Male; D009130:Muscle, Smooth / Q000737:chemistry*; D011237:Predictive Value of Tests; D011379:Prognosis; D020127:Recovery of Function; D016896:Treatment Outcome; D014517:Ureteral Obstruction / Q000601:surgery*
chemical_list: D003094:Collagen