In former studies we showed in a rat model of renal transplantation that Mesenchymal Stromal Cells (MSC) prevent acute rejection in an independent way of their endowing in the graft. In this study we investigated whether MSC operate by resetting cytokine network and Scatter Factor systems, i.e. Hepatocyte Growth Factor (HGF), Macrophage Stimulating Protein (MSP) and their receptors Met and RON, respectively. MSC were injected into the renal artery soon after reperfusion. Controls were grafted untreated and normal rats. Rats were sacrificed 7 days after grafting. Serum and renal tissue levels of IFN-γ, IL-1, IL-2, IL-4, IL-6, IL-10, MSP/RON, HGF/Met systems, Treg lymphocytes were investigated. In grafted untreated rats IFN-γ increased in serum and renal tissue and IL-6 rose in serum. MSC prevented both the phenomena, increased IL-10 serum levels and Treg number in the graft. Furthermore MSC increased serum and tissue HGF levels, Met tubular expression and prevented the suppression of tubular MSP/RON expression. Our results demonstrate that MSC modify cytokine network to a tolerogenic setting, they suppress Th1 cells, inactivate monocytes/macrophage, recruit Tregs. In addition, MSC sustain the expression of the Scatter Factor systems expression, i.e. systems that are committed to defend survival and stimulate regeneration of tubular cells.

We studied Mesenchymal Stromal Cells (MSC) effects in experimental Unilateral Ureteral Obstruction (UUO), a fibrogenic renal disease. Rats were divided in 5 groups: sham, UUO, MSC treated-UUO, ACEi treated-UUO, MSC+ACEi treated- UUO. Data were collected at 1, 7, 21 days. UUO induced monocyte renal infiltration, tubular cell apoptosis, tubular atrophy, interstitial fibrosis and overexpression of TGFβ, Renin mRNA (RENmRNA), increase of Renin, Angiotensin II (AII) and aldosterone serum levels. Both lisinopril (ACEi) and MSC treatment prevented monocyte infiltration, reduced tubular cell apoptosis, renal fibrosis and TGFβ expression. Combined therapy provided a further suppression of monocyte infiltration and tubular injury. Lisinopril alone caused a rebound activation of Renin-Angiotensin System (RAS), while MSC suppressed RENmRNA and Renin synthesis and induced a decrease of AII and aldosterone serum levels. Furthermore, in in-vitro and in-vivo experiments, MSC inhibit Human antigen R (HuR) trascription, an enhancer of RENmRNA stability by IL10 release. In conclusion, we demonstrate that in UUO MSC prevent fibrosis, by decreasing HuR-dependent RENmRNA stability. Our findings give a clue to understand the molecular mechanism through which MSC may prevent fibrosis in a wide and heterogeneous number of diseases that share RAS activation as common upstream pathogenic mechanism.

Background: Extended criteria donors (ECD) are widely utilized due to organ shortage, but they may increase the risk of graft dysfunction and poorer outcomes. Hypothermic oxygenated perfusion (HOPE) is a recent organ preservation strategy for marginal kidney and liver grafts, allowing a redirect from anaerobic metabolism to aerobic metabolism under hypothermic conditions and protecting grafts from oxidative species–related damage. These mechanisms may improve graft function and survival. Objective: With this study, we will evaluate the benefit of end-ischemic HOPE on ECD grafts for livers and kidneys as compared to static cold storage (SCS). The aim of the study is to demonstrate the ability of HOPE to improve graft function and postoperative outcomes of ECD kidney and liver recipients. Methods: This is an open-label, single-center randomized clinical trial with the aim of comparing HOPE with SCS in ECD kidney and liver transplantation. In the study protocol, which has been approved by the ethics committee, 220 patients (110 liver recipients and 110 kidney recipients) will be enrolled. Livers and kidneys assigned to the HOPE group undergo machine perfusion with cold Belzer solution (4-10°C) and continuous oxygenation (partial pressure of oxygen of 500-600 mm Hg). In the control group, livers and kidneys undergoing SCS are steeped in Celsior solution and stored on ice. Using the same perfusion machine for both liver and kidney grafts, organs are perfused from the start of the back-table procedure until implantation, without increasing the cold ischemia time. For each group, we will evaluate clinical outcomes, graft function tests, histologic findings, perfusate, and the number of allocated organs. Publication of the results is expected to begin in 2021. Results: Dynamic preservation methods for organs from high-risk donors should improve graft dysfunction after transplantation. To date, we have recruited 108 participants. The study is ongoing, and recruitment of participants will continue until January 2020. Conclusions: The proposed preservation method should improve ECD graft function and consequently the postoperative patient outcomes. Trial Registration: ClinicalTrials.gov NCT03837197; https://clinicaltrials.gov/ct2/show/NCT03837197 ; Archived by WebCite® at http://www.webcitation.org/76fSutT3R International Registered Report Identifier (IRRID): DERR1-10.2196/13922

For a long time, ABO incompatible living donor kidney transplantation has been considered contraindicated, due to the presence of isohemagglutinins, natural antibodies reacting with non-self ABO antigens. However, as the demand for kidney transplantation is constantly growing, methods to expand the donor pool have become increasingly important. Thus, in the last decades, specific desensitization strategies for ABOi transplantation have been developed. Nowadays, these regimens consist of transient removal of preformed anti-A or anti-B antibodies by using plasmapheresis or immunoadsorption and B-cell immunity modulation by CD20+ cells depletion with rituximab, in association with maintenance immunosuppression including corticosteroids, tacrolimus and mycophenolate mofetil. The outcome in ABOi kidney transplantation have markedly improved over the years. In fact, although randomized trials are still lacking, recent meta analysis has revealed that there is no difference in terms of graft and patient’s survival between ABOi and ABO compatible kidney transplant, even in the long term. However, many concerns still exist, because ABOi kidney transplantation is associated with an increased risk of bleeding and infectious complications, partly related to the effects of extracorporeal treatments and the strong immunosuppression. Thus, a continuous improvement in desensitization strategies, with the aim of minimize the immunosuppressive burden, on the basis of immune pathogenesis, antibodies titers and/or ABO blood group, is warranted. In this review, we discuss the main immune mechanisms involved in ABOi kidney transplantation, the pathogenesis of tolerance and the desensitization regimens, including immunoadsorption and plasmapheresis and the immunosuppressive protocol. Finally, we provide an overview on outcome and future perspectives in ABOi kidney transplant.