Development Of Graft Vasculopathy Research Articles

Abnormal Nailfold Capillaries in Patients after Hand Transplantation.

Background: The development of graft vasculopathy may play a role in the long-term deterioration of hand grafts. The aim of study was to examine the patterns of the nailfold capillaries in hand transplant recipients. Methods: the study was performed on six patients who received hand transplantation. To normalize for the effect of immunosuppression an age- and sex-matched group of 12 patients with active kidney transplant was selected. As an additional control group, 12 healthy volunteers were recruited. Nailfold videocapillaroscopy was performed in all participants. Additionally, serum concentrations of vascular endothelial growth factor (VEGF) were measured. Results: Videocapillaroscopic examination of the hand allografts revealed significant abnormalities: including capillary disorganization and microhaemorrhages. The number of capillaries was reduced, the vessels were enlarged and branched. Surprisingly, similar, albeit slightly less pronounced, changes were seen in the nailfolds of healthy hands of the limb transplant recipients. In kidney transplant recipients the capillaroscopic pattern was general normal and comparable to healthy individuals. Moreover, serum concentrations of VEGF in all participants correlated with average capillary diameter in capillaroscopy. Conclusions: in hand transplant recipients advanced microvascular abnormalities are found in nailfold capillaroscopic pattern in both transplanted and own extremities connected with elevated levels of VEGF.

Sodium Sulfite Exacerbates Allograft Vasculopathy and Affects Tryptophan Breakdown in Murine Heterotopic Aortic Transplantation

Graft vasculopathy is the main feature of chronic rejection in organ transplantation, with oxidative stress being a major trigger. Inflammation-associated prooxidant processes may be controlled by antioxidants; however, interference with redox-regulated mechanisms is a complex endeavor. An essential feature of the cellular immune response is the acceleration of tryptophan (Trp) breakdown, leading to the formation of several bioactive catabolites. Long-term activation of this immunobiochemical pathway contributes to the establishment of a tolerogenic environment, thereby supporting allograft survival. Herein, the impact of the antioxidant sodium sulfite on the development of graft vasculopathy was assessed in murine aortic transplantation. Allogeneic (BALB/c to C57BL/6) heterotopic murine aortic transplantations were performed. Animals were left untreated or were treated with 10 μl of 0.1 M, of 0.01 M sodium sulfite, or of 0.1 M sodium sulfate, intraperitoneally once/day, until postoperative day (POD) 100. Grafts were assessed by histology, immunohistochemistry, and adhesion molecule gene expression. Serum concentrations of tryptophan and its catabolite kynurenine (Kyn) were measured. On day 100, graft vasculopathy was significantly increased upon treatment with 0.1 M sodium sulfite, compared to allogeneic untreated controls (p = 0.004), which correlated with a significant increase of α-smooth-muscle-actin, Vcam-1, and P-selectin. Serum Kyn concentrations increased in the allogeneic control group over time (p < 0.05, POD ≥ 50), while low-dose sodium sulfite treatment (0.01 M) treatment resulted in a decrease in Kyn levels over time (p < 0.05, POD ≥ 10), compared to the respective baselines (p < 0.05). Longitudinal analysis of serum metabolite concentrations in the different treatment groups further identified an overall effect of sodium sulfite on Kyn concentrations. Antioxidative treatment may result in ambivalent consequences. Our data reveal that an excess of antioxidants like sodium sulfite can aggravate allograft vasculopathy, which further highlights the challenges associated with interventions that interfere with the complex interplay of redox-regulated inflammatory processes.

Treatment of Therapy-Resistant Hyperlipidaemia after Heart Transplant with PCSK9-Inhibitors

Purpose Hyperlipidemia is a major factor in the development of graft vasculopathy (GVP) after heart transplant. The incidence of hyperlipidaemia in heart transplant (HTX) patients under immunosuppressive therapy is 74% in the first year, and 91% in the first five years. Lipid-lowering therapy with statins presents a great challenge due to interactions and adverse effects. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have already proven very effective in high-risk cardiovascular patients. In our centre, PCSK9-inhibitors have been administered to selected HTX-patients, in which the target LDL-Cholesterol of 100mg/dl could not be reached with reasonable doses of statins and/or Etizimib. Methods In the period 02/2017 to 06/2018, 15 adult HTX-patients (median age 55.3, (25-75%: 48.2-64.6), 25% female) were selected. The patients were at a median of 35.1 (25-75%: 28.4-78.6) months post-HTX. The selected patients were evaluated together in the lipid clinic (licenced for PCSK9-inhibitors). Therapy was initiated with Alirocumab 75mg. Statin-therapy was changed and appropriately documented when changes in lipid-parameters and/or adverse effects occurred. In order to evaluate incidence and prevalence of myopathy and hepatotoxicity, CK and liver enzymes and were measured 1, 3, 6, 9, 12, and 15 months post conversion. Analysis of effectiveness were conducted by measuring blood lipids (LDL-C, HDL, total cholesterol, triglycerides, and LP(a)). Results Total cholesterol (231 (198-245) vs. 151 (139-175) mg/dl; p Conclusion Therapy with PCSK9-inhibitors (Alirocumab) constitutes an effective and safe option in therapy of hyperlipidaemia after heart transplant. Under treatment liver and kidney parameters stayed stable, while a significant reduction of lipid levels could be achieved. To evaluate the long-term effects of PCSK9-Inhibitors longer observation period is necessary.

MTOR Inhibition and Clinical Transplantation: Heart.

This brief overview discusses recent data on the use of mammalian target of rapamycin (mTOR) inhibitors in heart transplantation. Trials on de novo use have shown good efficacy of mTOR inhibitors; however, adverse events are often seen. Conversion protocols in long-term patients are mainly used in patients with renal insufficiency. Calcineurin inhibitor minimization and conversion to calcineurin inhibitor-free protocols have proven to stabilize renal function in recent trials. Lastly, beneficial effects of mTORs against the development of graft vasculopathy, cytomeglovirus infection and malignancy have been shown. Nevertheless, lower tolerability of the drug has affected the long-term use in patients. Future consideration of using mTORs will be individualized protocols in special subpopulation after heart transplantation.

440: FR167653 Ameliorates Expression of Proinflammatory Mediators in HUVEC and Human Monocytes

events such as acute coronary syndrome, which originate from endothelial cells. When sCD40L is present in human plasma, it is mainly derived from activated platelets. This may lead to activation of endothelial cells resulting in atherosclerosis and eventually atherothrombosis. Therefore, the aim of the present study was to investigate differential gene expression profiles after stimulation of human endothelial cells (HUVEC) with sCD40L. Methods and Materials: HUVEC were stimulated with sCD40L for 2 hours. Differential gene expression patterns were evaluated with cDNA microarry analysis. Significantly up-regulated gene expression was confirmed and quantitated by Real-time-PCR as well as ELISA. Results: Stimulation of HUVEC with sCD40L leads to a profound release of proinflammatory mediators like IL-8, ICAM1, ISGF3 (interferon-stimulated transcription factor 3) as well as MCP-1 on a transcriptional level. In addition, gene expression profiling revealed a highly significant increase in expression of the macrophage inflammatory protein 2 (MIP-2), also known as GRO-beta, a receptor of CXCL2. This was quantitated as approximatly 30 fold up-regulation by real-time-PCR as well as in ELISA analysis (8 fold at 8 to 24 hours) derived from supernations. Conclusions: Proinflammatory mediators as well as MIP-2 play an important role in the chemoattraction of macrophages, which underlines the key role of CD40L as a link between thrombotic events and inflammatory processes in atherosclerosis as well as the development of graft vasculopathy. Therefore targeting the chemokine MIP-2 up-regulation might be a potential approach to prevent the progression of atherosclerotic diseases.

Survival in Allosensitized Children After Listing for Cardiac Transplantation

Little is known about the effect of pre-transplant alloantibody in the pediatric cardiac transplant population. All cardiac listings (n = 298) at Children's Hospital of Pittsburgh from January 1990 through February 2006 were reviewed to determine the impact of allosensitization on transplantation outcomes. Analysis focused on: (1) wait list outcomes; (2) survival from the time of listing, regardless of subsequent transplantation; (3) post-transplant graft and patient survival; and (4) post-transplant freedom from graft vasculopathy. Institutional policy required a negative, prospective crossmatch for candidates with panel-reactive antibody >20%. Alloantibody data were available for 252 (85%) listings. Median time to transplantation was greater for sensitized vs non-sensitized subjects (2.7 months vs 1.3 months; p = 0.02). At 1 year after listing, sensitized subjects had a higher incidence of death (22% vs 8.4%; p = 0.055). Survival at all time-points after listing (regardless of transplantation) was worse for sensitized subjects (p = 0.04). Although no statistically significant differences in post-transplant graft or patient survival were noted, pre-transplant allosensitization was associated with decreased freedom from graft vasculopathy (hazard ratio [HR] 2.76, 95% confidence interval [CI] 1.18 to 6.45; p = 0.019). A policy requiring a negative, prospective crossmatch for highly sensitized candidates is associated with longer wait list time and higher mortality after listing. The development of graft vasculopathy appears to be influenced by the presence of pre-transplant alloantibody.

Sanglifehrin A Blocks Key Dendritic Cell Functions In Vivo and Promotes Long-Term Allograft Survival Together with Low-Dose CsA

Sanglifehrin A (SFA) is a novel compound with unsurpassed cyclophilin-binding affinity, but relatively low direct antilymphocytic activity. Here, we report the capacity of SFA to selectively inhibit key dendritic cell (DC) functions in vivo and to suppress acute and chronic heart allograft rejection. We show that in vivo, SFA profoundly decreases DC receptor-mediated endocytosis and macropinocytosis and DC-T-cell allostimulatory activity. Furthermore, SFA abrogates >90% of IL-12p70 production in vivo while having no significant effect on IL-10 and TNF-alpha production. In a rat vascularized heart transplant model, SFA alone did not prevent graft rejection and rejection occurred within 23 days after low-dose CsA, whereas addition of SFA to low-dose CsA promoted long-term graft survival (median survival time >100 days; p = 0.0007). With respect to chronic rejection, SFA + CsA almost completely prevented graft arteriosclerosis compared to animals treated with CsA alone and controls. We propose that SFA represents a novel class of immunophilin-binding immunosuppressants with high activity against DCs and the development of graft vasculopathy in CsA-treated recipients.

THYMOGLOBULINE INDUCTION THERAPY CREATES EXCELLENT LONG-TERM OUTCOME OF PATIENTS WITH POSITIVE LYMPHOCYTE CROSSMATCH AFTER CARDIAC TRANSPLANTATION

P641 Aims: The effect of pretransplant sensitization on outcome after cardiac transplant has been controversial. Positive lymphocyte crossmatch (LCM) has been associated with with increased incidence of early and severe allograft rejection, vasculopathy and decreased survival. The aim of this study was to analyse outcome of cardiac transplant patients with positive LCM undergoing thymoglobuline induction therapy. Methods: A total number of 341 cardiac transplant patients underwent LCM since 1995. All patients received thymoglobuline induction therapy (2mg/kg/d for 3-7 days). maintenance immunosuppression consisted of calcineurinantagonists (Cyclosporine or tacrolimus), antiproliferative therapy (azathioprine or mycophenolate) and low dose steroids. Patients were divided into two groups (negative LCM, positive LCM) and were analysed for survival, rejection incidence and development of graft-vasculopathy. Results: A total of 36 patients (11%) showed a positive LCM. Patients in both groups were similar on regard to age, sex, diagnosis, previous cardiac operations, retransplantation and implantation of an assist device. There was a significantly higher number of patients with pretransplant PRA [gt]10% in the LCM pos. group (19% vs 8%, p=0.04). One-year (pos:83% vs neg: 83%) and eight year (71% vs 72%) survival were similar between the two groups. Freedom from rejection was also similar (92% vs 90%). Incidences of overall (any changes) and severe ([gt]50% stenosis) graftvasculopathy were similar and low in both groups. (overall: 25% vs 20%; severe: 14% vs 5%). Conclusions: Thymoglobuline induction therapy in patients transplanted across a positive LCM results in similar good outcome as in unsensitized patients.

Alloantigen profile of graft vascular endothelial cells in rat heart allograft rejection: expression of MHC and non-MHC alloantigens

Summary The alloantigen profile of vascular endothelial cells has been studied in a rat experimental model for MHC-mismatched and MHC-matched (non-MHC mismatched) allogeneic heart transplantation (TX). Hearts were studied for alloantibody deposition in the graft vasculature and the occurrence of vasculopathy. In addition reactivity of allosera with in vitro cultures of graft-type vascular endothelial cells was examined. Alloantibodies were seen deposited in the graft vasculature in MHC-mismatched as well as in MHC-matched TX. In MHC-matched hearts the most dominant vasculopathy consisted of early arteriosclerotic lesions. In vitro studies demonstrated that, in addition to MHC alloantigens, heart vascular endothelial cells express non-MHC alloantigens. These endothelial non-MHC alloantigens are constitutively expressed by heart endothelial cells, and expression is not influenced by cytokine stimulation. We conclude that humoral immune response against these endothelial non-MHC alloantigens may play an important role in development of graft vasculopathy and particularly of arteriosclerotic lesions.