Chronic allograft nephropathy

Curcumin Blunts IL-6 Dependent Endothelial-to-Mesenchymal Transition to Alleviate Renal Allograft Fibrosis Through Autophagy Activation

Fibrosis contributes to graft loss in chronic renal allograft injury. Endothelial-to-mesenchymal transition (EndMT) plays an important role in the development of fibrosis following kidney transplantation. Autophagy plays an important role in the homeostasis of diverse cell types including endothelial cells. Here we demonstrate that inhibition of autophagy by treatment with 3-methyladenine (3-MA) or by silencing autophagy-related (ATG)5 promoted interleukin (IL)-6-dependent EndMT in human umbilical vein endothelial cells (HUVECs) and human renal glomerular endothelial cells (HRGECs), and autophagy inactivation was associated with EndMT in patients with chronic allograft dysfunction. IL-6 level was significantly higher in the culture medium of HUVECs transfected with ATG5 siRNA or treated with 3-MA compared to the respective control groups. IL-6 application induced EndMT in HUVECs and HRGECs, whereas antibody-mediated neutralization of IL-6 suppressed EndMT induced by ATG5 silencing. The protective role of curcumin (Cur) against allograft fibrosis was confirmed in a rat kidney transplantation model of F344 donors to Lewis recipients. Curcumin-a natural polyphenol compound with known antifibrotic effects in various tissues-alleviated IL-6-induced EndMT and promoted autophagy in the allografted organ and in HUVECs. This is the first demonstration of the role of autophagy in renal allograft fibrosis; our findings indicate that curcumin can alleviate chronic renal allograft injury by suppressing IL-6-dependent EndMT via activation of autophagy.

Inverse Association Between the Quantity of Human Peripheral Blood CXCR5+IFN-γ+CD8+ T Cells With De Novo DSA Production in the First Year After Kidney Transplant

BACKGROUND

We recently reported that a novel CXCR5IFN-γCD8 T-cell subset significantly inhibits posttransplant alloantibody production in a murine transplant model. These findings prompted the current study to investigate the association of human CD8 T cells with the same phenotype with the development of de novo donor-specific antibody (DSA) after kidney transplantation.

METHODS

In the current studies, we prospectively and serially analyzed peripheral blood CD8 and CD4 T-cell subsets and monitored for the development of de novo DSA in kidney transplant recipients during the first-year posttransplant. We report results on 95 first-time human kidney transplant recipients with 1-year follow-up.

RESULTS

Twenty-three recipients (24.2%) developed de novo DSA within 1-year posttransplant. Recipients who developed DSA had significantly lower quantities of peripheral CXCR5IFN-γCD8 T cells (P = 0.01) and significantly lower ratios of CXCR5IFN-γCD8 T cell to combined CD4 Th1/Th2 cell subsets (IFN-γCD4 and IL-4CD4 cells; P = 0.0001) compared to recipients who remained DSA-negative over the first-year posttransplant.

CONCLUSIONS

Our data raise the possibility that human CXCR5IFN-γCD8 T cells are a homolog to murine CXCR5IFN-γCD8 T cells (termed antibody-suppressor CD8 T cells) and that the quantity of CXCR5IFN-γCD8 T cells (or the ratio of CXCR5IFN-γCD8 T cells to Th1/Th2 CD4 T cells) may identify recipients at risk for development of DSA.

Updates on acute and chronic rejection in small bowel and multivisceral allografts

PURPOSE OF REVIEW

The surgical management of short bowel syndrome now includes intestinal (ITx) and multivisceral transplantation (MVTx), which has advanced and is now a sustainable option for the treatment of intestinal failure. Improvements in immunosuppressive therapies, excellence in surgical and medical management and enhanced post-transplant monitoring have all contributed to optimizing this solid organ transplant as a means of supplanting the diseased native bowel and alimentary tract with a functional alternative.

RECENT FINDINGS

Post-transplant management is a critical and challenging phase of gastrointestinal transplantation, and the transplant pathologist is an essential member of the transplant team who identifies many of the early and late complications after ITx and MVTx. Among the most injurious and common complications of ITx and MVTx is acute rejection and, to a lesser degree, chronic rejection. Both of these broad categories of rejection are principally identified by histopathological changes in the allograft; however, biomarkers and other laboratory analytes are rapidly evolving into critical ancillary tools in identifying and further characterizing the rejection process. Thus, the transplant pathologist must also be able to utilize numerous other laboratory tests and panels of molecular biomarkers that provide supplementary information to accompany the biopsy interpretation and clinical suspicion of rejection.

SUMMARY

Using biopsies and an assortment of additional approaches, the transplant pathologist is now able to provide swift and detailed information regarding the rejection process in the gastrointestinal transplant. This enables the clinical team to properly and successfully intercede, contributing to enhanced patient and graft survival.

Alloprimed CD8(+) T cells regulate alloantibody and eliminate alloprimed B cells through perforin- and FasL-dependent mechanisms

While it is well known that CD4(+) T cells and B cells collaborate for antibody production, our group previously reported that CD8(+) T cells down-regulate alloantibody responses following transplantation. However, the exact mechanism involved in CD8(+) T cell-mediated down-regulation of alloantibody remains unclear. We also reported that alloantibody production is enhanced when either perforin or FasL is deficient in transplant recipients. Here, we report that CD8(+) T cell-deficient transplant recipient mice (high alloantibody producers) exhibit an increased number of primed B cells compared to WT transplant recipients. Furthermore, CD8(+) T cells require FasL, perforin and allospecificity to down-regulate posttransplant alloantibody production. In vivo CD8-mediated clearance of alloprimed B cells was also FasL- and perforin-dependent. In vitro data demonstrated that recipient CD8(+) T cells directly induce apoptosis of alloprimed IgG1(+) B cells in co-culture in an allospecific and MHC class I-dependent fashion. Altogether these data are consistent with the interpretation that CD8(+) T cells down-regulate posttransplant alloantibody production by FasL- and perforin-dependent direct elimination of alloprimed IgG1(+) B cells.

Improving the safety of tolerance induction: chimerism and cellular co-treatment strategies applied to vascularized composite allografts

Although vascularized composite allografts (VCAs) have been performed clinically for a variety of indications, potential complications from long-term immunosuppression and graft-versus-host disease remain important barriers to widespread applications. Recently it has been demonstrated that VCAs incorporating a vascularized long bone in a rat model provide concurrent vascularized bone marrow transplantation that, itself, functions to establish hematopoietic chimerism and donor-specific tolerance following non-myeloablative conditioning of recipients. Advances such as this, which aim to improve the safety profile of tolerance induction, will help usher in an era of wider clinical VCA application for nonlife-saving reconstructions.

Greater efficacy of tolerance induction with cyclosporine versus tacrolimus in composite tissue allotransplants with less myeloablative conditioning

BACKGROUND

Previous studies demonstrated that both cyclosporine and tacrolimus in combination with antilymphocyte globulin could facilitate mixed chimerism and induce tolerance to composite tissue allotransplants under partial myeloablative conditioning. The purpose of this study was to compare the efficacy of cyclosporine and tacrolimus.

METHODS

Brown-Norway and Lewis rats were used as composite tissue allotransplant donors and recipients, respectively. Cyclosporine groups I (n = 6), II (n = 9), and III (n = 5) received subcutaneous injection of 16 mg/kg cyclosporine (days 0 to 10); intraperitoneal injection of 5 mg of antilymphocyte globulin (days -1 and 10); and 0-, 200-, and 400-cGy total body irradiation (day -1), respectively. Tacrolimus groups IV (n = 6), V (n = 7), and VI (n = 8) received intraperitoneal injection of 1 mg/kg tacrolimus (days 0 to 10) and 5 mg of antilymphocyte globulin (days -1 and 10); and 0-, 200-, and 400-cGy total body irradiation (day -1), respectively. Recipients underwent hind-limb osteomyocutaneous flap composite tissue allotransplantation on day 0. Chimerism levels were determined 2 weeks after composite tissue allotransplantation, and acceptance was defined as complete survival of the composite tissue allotransplant to the endpoint of the experiment at 150 days.

RESULTS

Chimerism levels 2 weeks after composite tissue allotransplant averaged 3.4, 4.9, 29, 2.4, 4.9, and 16 percent composite tissue allotransplant, and acceptance rates were 0, 33.3, 80, 0, 0, and 13 percent in group I, II, III, IV, V, and VI, respectively.

CONCLUSION

Despite relatively late development for clinical use in transplantation, tacrolimus has not proved advantageous for composite tissue allotransplant acceptance and tolerance when compared with cyclosporine.