Microbiota, renal disease and renal transplantation

Abstract

Aim of this frontier review has been to highlight the role of microbiota in healthy subjects and in patients affected by renal diseases with particular reference to renal transplantation. The microbiota has a relevant role in conditioning the healthy status and the diseases. In particular gut microbiota is essential in the metabolism of food and has a relevant role for its relationship with the immune system. The indigenous microbiota in patients with chronic renal failure is completely different than that of the healthy subjects and pathobionts appear. This abnormality in microbiota composition is called dysbiosis and may cause a rapid deterioration of the renal function both for activating the immune system and producing large quantity of uremic toxins. Similarly, after renal trans-plantation the microbiota changes with the appearance of pathobionts, principally in the first period because of the assumption of immunosuppressive drugs and antibiotics. These changes may deeply interfere with the graft outcome causing acute rejection, renal infections, diarrhea, and renal interstitial fibrosis. In addition, change in the microbiota may modify the metabolism of immuno-suppressive drugs causing in some patients the need of modifying the immunosuppressant dosing. The restoration of the indigenous microbiota after transplantation is important, either to avoiding the complications that impair the normal renal graft, and because recent studies have documented the role of an indigenous microbiota in inducing tolerance towards the graft. The use of prebiotics, probiotics, smart bacteria and diet modification may restore the indigenous microbiota, but these studies are just at their beginning and more data are needed to draw definitive conclusions.

Keywords: Gut commensals, Microbioma, Microbiota, Renal disease, Renal trans-plantation, Transplant outcomes

Core Tip: Recent studies on the microbiota have documented that a microbiota modification, related to the assumption of immunosuppressive drugs and of antibiotics, as happens in the first period after transplantation may modify the outcomes of the graft. Indeed, dysbiosis may cause acute rejections and reduce the possibility of a tolerance status. In addition, dysbiosis if often the cause of infections and renal fibrosis. Dysbiosis may also cause diarrhea that is a frequent and severe complication in the transplanted patient. Modification of dysbiosis is possible with an appropriate treatment, but studies on this topic are just at their beginning.