Factors influencing success of pelvic organ prolapse repair using porcine dermal implant Pelvicol®

Inhibition of complement component C5 protects porcine chondrocytes from xenogeneic rejection

OBJECTIVE

Tissue-based xenografts such as cartilage are rejected within weeks by humoral and cellular mechanisms that preclude its clinical application in regenerative medicine. The problem could be overcome by identifying key molecules triggering rejection and the development of genetic-engineering strategies to counteract them. Accordingly, high expression of α1,2-fucosyltransferase (HT) in xenogeneic cartilage reduces the galactose α1,3-galactose (Gal) antigen and delays rejection. Yet, the role of complement activation in this setting is unknown.

DESIGN

To determine its contribution, we assessed the effect of inhibiting C5 complement component in α1,3-galactosyltransferase-knockout (Gal KO) mice transplanted with porcine cartilage and studied the effect of human complement on porcine articular chondrocytes (PAC).

RESULTS

Treatment with an anti-mouse C5 blocking antibody for 5 weeks enhanced graft survival by reducing cellular rejection. Moreover, PAC were highly resistant to complement-mediated lysis and primarily responded to human complement by releasing IL-6 and IL-8. This occurred even in the absence of anti-Gal antibody and was mediated by both C5a and C5b-9. Indeed, C5a directly triggered IL-6 and IL-8 secretion and up-regulated expression of swine leukocyte antigen I (SLA-I) and adhesion molecules on chondrocytes, all processes that enhance cellular rejection. Finally, the use of anti-human C5/C5a antibodies and/or recombinant expression of human complement regulatory molecule CD59 (hCD59) conferred protection in correspondence with their specific functions.

CONCLUSIONS

Our study demonstrates that complement activation contributes to rejection of xenogeneic cartilage and provides valuable information for selecting approaches for complement inhibition.

Risk factors for recurrence of genital prolapse

PURPOSE OF REVIEW

To review the available evidence regarding those risk factors potentially predicting a recurrence of pelvic organ prolapse (POP).

RECENT FINDINGS

POP is a very common condition in parous women, requiring very often a surgical treatment which may need to be repeated in up to 29% of cases. In the past few years, researchers have focused their attention on the evaluation of risk factors involved in either POP development or recurrence. Recent papers have reported the importance of genetic factors that could be responsible for an inherited weakness of the pelvic floor, predisposing to POP occurrence and/or recurrence. Moreover, a history of genital prolapse at the time of an elective hysterectomy, as well as an inappropriate reconstructive surgical procedure, can predict and be associated with POP development.

SUMMARY

POP recurrence can be associated with a combination of predisposing, inciting, and intervening factors. Based on actual knowledge, it is not possible to weight or score the importance of each single risk factor reported in literature for the development of POP recurrence. Larger series (collected with validated diagnostic and therapeutic tools) and longer follow-up are, therefore, needed to draw definitive conclusions on this issue.