Everolimus-induced loss of wound strength can be prevented by a short postoperative delay in its administration

The Effect of Mycophenolate Mofetil on Early Wound Healing in a Rodent Model

Background

Immunosuppressant agents are inevitable for solid organ recipients, but may have a negative effect on wound healing that is difficult to measure because of clinical use of a polydrug regime. The evidence on mycophenolate mofetil (MMF) is scarce and contradictory. This study aims to investigate the effect of MMF administration on wound healing.

Methods

Ninety-six male Wistar rats divided into 4 groups underwent anastomotic construction in ileum and colon at day 0. Three groups received daily oral doses of 20 or 40 mg/kg MMF or saline (control group) from day 0 until the end of the experiment. Half of each group was analyzed after 3 days and half after 7 days. Another group started the medication 3 days after the laparotomy and was analyzed after 7 days, half of this group received 20 mg/kg and half 40 mg/kg MMF. Wound strength in anastomoses and in the abdominal wall was measured using bursting pressure, breaking strength, and histology. Trough levels were measured.

Results

Significant differences in wound strength were seen in ileum tissue after 3 days, which surprisingly showed a stronger anastomosis in the experimental groups. Bursting pressure as well as breaking strength was higher in the low-dose and high-dose MMF group compared with the control group. A negative effect was measured in abdominal wall tissue for the highest-dose group, which disappeared when the medication was delayed for 3 days. Histology showed poorer bridging of the submucosal layer and more polymorphonuclear cell infiltration in the ileum specimens of the control group compared with the treatment groups.

Conclusions

As a single agent in a preclinical wound healing model in the rat, MMF has no negative effect on healing of bowel anastomoses but might have a negative effect on the healing of abdominal wall.

The role of everolimus in liver transplantation

During the last 5 decades, liver transplantation has witnessed rapid development in terms of both technical and pharmacologic advances. Since their discovery, calcineurin inhibitors (CNIs) have remained the standard of care for immunosuppression therapy in liver transplantation, improving both patient and graft survival. However, adverse events, particularly posttransplant nephrotoxicity, associated with long-term CNI use have necessitated the development of alternate treatment approaches. These include combination therapy with a CNI and the inosine monophosphate dehydrogenase inhibitor mycophenolic acid and use of mammalian target of rapamycin (mTOR) inhibitors. Everolimus, a 40-O-(2-hydroxyethyl) derivative of mTOR inhibitor sirolimus, has a distinct pharmacokinetic profile. Several studies have assessed the role of everolimus in liver transplant recipients in combination with CNI reduction or as a CNI withdrawal strategy. The efficacy of everolimus-based immunosuppressive therapy has been demonstrated in both de novo and maintenance liver transplant recipients. A pivotal study in 719 de novo liver transplant recipients formed the basis of the recent approval of everolimus in combination with steroids and reduced-dose tacrolimus in liver transplantation. In this study, everolimus introduced at 30 days posttransplantation in combination with reduced-dose tacrolimus (exposure reduced by 39%) showed comparable efficacy (composite efficacy failure rate of treated biopsy-proven acute rejection, graft loss, or death) and achieved superior renal function as early as month 1 and maintained it over 2 years versus standard exposure tacrolimus. This review provides an overview of the efficacy and safety of everolimus-based regimens in liver transplantation in the de novo and maintenance settings, as well as in special populations such as patients with hepatocellular carcinoma recurrence, hepatitis C virus-positive patients, and pediatric transplant recipients. We also provide an overview of ongoing studies and discuss potential expansion of the role for everolimus in these settings.