Update on the reciprocal interference between immunosuppressive therapy and gut microbiota after kidney transplantation

Gut microbiota is often modified after kidney transplantation. This principally happens in the first period after transplantation. Antibiotics and, most of all, immunosuppressive drugs are the main responsible. The relationship between immunosuppressive drugs and the gut microbiota is bilateral. From one side immunosuppressive drugs modify the gut microbiota, often generating dysbiosis; from the other side microbiota may interfere with the immunosuppressant pharmacokinetics, producing products more or less active with respect to the original drug. These phenomena have influence over the graft outcomes and clinical consequences as rejections, infections, diarrhea may be caused by the dysbiotic condition. Corticosteroids, calcineurin inhibitors such as tacrolimus and cyclosporine, mycophenolate mofetil and mTOR inhibitors are the immunosuppressive drugs whose effect on the gut microbiota is better known. In contrast is well known how the gut microbiota may interfere with glucocorticoids, which may be transformed into androgens. Tacrolimus may be transformed by micro biota into a product called M1 that is 15-fold less active with respect to tacrolimus. The pro-drug mycophenolate mofetil is normally transformed in mycophenolic acid that according the presence or not of microbes producing the enzyme glu curonidase, may be transformed into the inactive product.

Clinical impact of complement deposition findings on biopsies in acute rejection episodes of pediatric renal transplant patients

INTRODUCTION

Rejection is the most important problem for renal graft function and survival. Complement system plays a key role in immune responses from host to graft. It was demonstrated that complement system activation is related with renal fibrosis. We evaluate clinical impact of complement deposition findings on biopsies in acute rejection episodes of pediatric renal transplant patients.

METHOD

Demographics of the patients, graft functions, acute rejection episodes and graft loss were recorded from data files of 165 pediatric renal transplant patients. Findings of 98 renal biopsies were retrospectively evaluated.

RESULTS

Thirty three patients with kidney transplant had 44 acute rejection episodes (32 pure cellular acute rejection episodes / 1 pure humoral acute rejection episode / 11 combined acute cellular and acute humoral rejection episodes) proven by biopsy. C1q staining was positive in 7 biopsies, C3 staining in 15 biopsies and, C4d staining in 15 biopsies. 26 patients had graft fibrosis. All patients with a rejection history had a significant decrease in GFR value during follow-up. Patients who did not have fibrotic changes in first biopsy had same level of deterioration of GFR when compared with patients who had fibrotic changes in first biopsy.

CONCLUSION

We could not demonstrate a significant relation between complement deposition and renal fibrosis, and between complement deposition and GFR values. Our data demonstrated that graft outcomes and graft loss after acute rejection episodes cannot be predicted only with complement deposition on graft or only with graft fibrosis.

Is it time to rethink combined liver-kidney transplant in hepatitis C patients with advanced fibrosis?

AIM

To reduce hepatic and extrahepatic complications of chronic hepatitis C in kidney transplant recipients.

METHODS

We conducted a systematic review of kidney only transplant in patients with hepatitis C and advanced fibrosis.

RESULTS

The 5 year patient survival of kidney transplant recipients with and without hepatitis C cirrhosis ranged from 31% to 90% and 85% to 92%, respectively. Hepatitis C kidney transplant recipients had lower 10-year survival when compared to hepatitis B patients, 40% and 90% respectively. There were no studies that included patients with virologic cure prior to kidney transplant that reported post-kidney transplant outcomes. There were no studies of direct acting antiviral therapy and effect on patient or graft survival after kidney transplantation.

CONCLUSION

Data on kidney transplant only in hepatitis C patients that reported inferior outcomes were prior to the development of potent direct acting antiviral. With the development of potent directing acting antiviral therapy for hepatitis C with high cure rates studies are needed to determine if patients with hepatitis C, including those with advanced fibrosis, can undergo kidney transplant alone with acceptable long term outcomes.

Current research on organ donor management

A shortage of organs is available for transplantation, with 116,000 patients on the Organ Procurement and Transplantation Network/United Network for Organ Sharing wait list. Because the demand for organs outweighs the supply, considerable care must be taken to maximize the number of organs transplanted per donor and optimize the quality of recovered organs. Studies designed to determine optimal donor management therapies are limited, and this research has many challenges. Although evidenced-based guidelines for managing potential organ donors do not exist, research in this area is increasing. This article reviews the existing literature and highlights recent trials that can guide management.