Failed endopyelotomy: Low expression of TGF beta regardless of the presence or absence of crossing vessels

Background and Objective: Endopyelotomy relies on Davis' intubated ureterot omy principle of healing by secondary intention and smooth-muscle regenerat ion. Approximately 15% of endopyelotomies fail, and the restrictured segmen t almost always shows evidence of reactive fibrosis with little smooth-musc le regeneration. Previous data suggests that an elevation of TGF beta in ob structed ureteropelvic junctures may be necessary for successful tissue rep air following endopyelotomy, The role of crossing vessels in endopyelotomy failure is very controversial, To better understand the pathophysiology of endopyelotomy failure, the expression of transforming growth factor-beta (T BG beta) in patients with a failed endopyelotomy and crossing vessels was c ompared with that in patients without crossing vessels, as well as those ha ving primary pyeloplasty or a normal ureteropelvic junction (UPJ), Materials and Methods: The expression of TGF beta was detected immunohistoc hemically in slide-mounted thin sections (4 mu m) cut from paraffin-blocked adult UPJ segments obtained during primary pyeloplasty (N = 11), secondary pyeloplasty after failed endopyelotomy with documented crossing vessels (N = 10), secondary pyeloplasty after failed endopyelotomy without crossing v essels (N = 11), and normal UPJs removed during nephrectomy for purposes un related to obstruction (N = 11), Expression was graded on a scale of 0 to 4 , Results: The combined failed endopyelotomy group had a significantly (P < 0 .05) lower level of TGF beta (1.9 +/- 0.7) than did primary obstructed UPJs (2.6 +/- 0.7). The TGF beta level in the crossing vessels group (1.9 +/- 0 .7) did not differ from that in the group without crossing vessels (1.8 +/- 0.7), nor did it differ from that in the group with normal UPJs (1.6 +/- 0 .7). As expected, primary obstructed UPJs had a significantly higher level of TGF beta than normal ones (P < 0.02). Conclusions: Obstructed UPJs that had failed endopyelotomy had a similarly reduced level of TGF beta whether or not crossing vessels were present. The se data suggest that an elevation of TGF beta in obstructed UPJs may be nec essary for successful tissue repair after endopyelotomy and that the presen ce of crossing vessels is probably not relevant.