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

Mammalian Target of Rapamycin Inhibitors and Wound Healing Complications in Kidney Transplantation: Old Myths and New Realities

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients' profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods.

DOES THE ASSOCIATION OF TACROLIMUS AND MYCOPHENOLATE MOFETIL CHANGE THE HEALING OF THE ABDOMINAL WALL? STUDY IN RATS SUBMITTED TO ISCHEMIA AND KIDNEY REPERFUSION

BACKGROUND

Tacrolimus and mycophenolate mofetil are immunosuppressive agents widely used on the postoperative period of the transplants.

AIM

To evaluate the influence of the association of them on the abdominal wall healing in rats.

METHODS

Thirty-six Wistar rats were randomly assigned in three groups of 12. On the early postoperative period, four of the control group and three of the experimental groups died. The three groups were nominated as follow: control group (GC, n=8); group I (GI, n=11, standard operation, mycophenolate mofetil and tacrolimus); group II (GII, n=10, standard operation, mycophenolate mofetil and tacrolimus). The standard operation consisted of right total nephrectomy and 20 min ischemia of the left kidney followed by reperfusion. Both NaCl 0.9% and the immunosuppressive agents were administered starting on the first postoperative day and continuing daily until the day of death on the 14th day. On the day of their deaths, two strips of the anterior abdominal wall were collected and submitted to breaking strength measurement and histological examination.

RESULTS

There were no significant differences in wound infection rates (p=0,175), in the breaking strength measurement and in the histological examination among the three groups.

CONCLUSION

The combination of the immunosuppressive agents used in the study associated with renal ischemia and reperfusion does not interfere in the abdominal wall healing of rats.

Immunosuppressive Drugs Alter α1-Antitrypsin Production in Hepatocytes: Implications for Epithelial Gap Repair

Immunosuppressive drugs are an inherent component of hematopoietic stem cell transplantation (HSCT) for the prevention of acute graft-versus-host disease (GVHD). Circulating α1-antitrypsin (AAT), a serine-protease inhibitor produced predominantly by hepatocytes that rises during acute phase responses, is lost in patient's stool due to gastrointestinal GVHD, and its augmentation has been found to attenuate GVHD. Here we explored the effect of immunosuppressive drugs on hepatocyte production of AAT and intestinal epithelial gap repair. The effect of commonly used immunosuppressants on AAT production was examined in vitro using HepG2 cells and primary mouse hepatocytes, and their impact on human intestinal epithelial cell line gap repair was evaluated. Sera from 12 allogeneic HSCT recipients, obtained at 14 days post-transplantation, predating the diagnosis of GVHD (n = 6), were examined for reepithelialization, with added clinical-grade AAT. Rapamycin compromised AAT production under inflammatory conditions. Mycophenolate mofetil and cyclosporine A (CSA) inhibited reepithelialization; AAT minimized the effect of CSA. Patient sera displayed superior gap repair with exogenous AAT. Functional insufficiency in circulating AAT may be the result of drug toxicities leading to ineffective gut reepithelization and compromised gut lining. Taken together, our data strengthen the rationale for incorporating AAT augmentation therapy into immunosuppressive treatment protocols.

Burn patients with history of kidney transplant experience increased incidence of wound infection

OBJECTIVE

To determine if history of kidney transplant is an independent risk factor for increased incidence of wound infection and other morbidities in burn patients.

BACKGROUND

While the goal of immunosuppression post-organ transplantation is to prevent graft rejection, it is often associated with significant adverse effects such as increased susceptibility to infection, drug toxicity, and malignancy. Burn injuries lead to a dysregulated hypermetabolic state and a compromised cutaneous barrier, which predisposes to infection and delayed wound healing. We surmise that a history of kidney transplant increases the risk of wound infection in in-hospital burn victims.

METHODS

A retrospective analysis was performed on 57,948 adults diagnosed in-hospital with a burn injury between 2008-2014, obtained from the Nationwide Inpatient Sample (NIS) by Healthcare Cost and Utilization Project (HCUP).

RESULTS

103 burn victims (0.2%) with a history of kidney transplant (KTX) were identified. Compared to burn patients without a history of transplant (No-KTX), they were older (54.3 ± 13.8 vs 49.8 ± 18.7; p = 0.001), more likely be insured under Medicare (69.9% vs 31.1%; p < 0.001), and less likely to have Medicaid (5.8% vs 17.2%; p = 0.002). Higher in-hospital mortality index scores were observed in KTX compared to no-KTX with p < 0.001. The incidence rates of complications such as wound infection (33.0 vs 16.3; p < 0.001) and acute renal failure (18.4 vs 7.7; p < 0.001) were significantly higher in the KTX group. After adjusting for confounding factors in multivariable analysis, the incidence of wound infection remained significantly higher. Burn patients with history of KTX were not more likely to be treated at a transplant (TX) center. TX centers were determined to have higher mortality rate, longer length of stay, and higher total hospital charges.

CONCLUSION

History of kidney transplant is an independent risk factor for increased incidence of wound infection in burn patients.