Role of biliary complications in chronic graft rejection after living donor liver transplantation

Postoperative biliary complications remain a substantial challenge after living donor liver transplantation,especially due to its heterogeneous clinical presentation.

Chronic Kidney Isograft and Allograft Rejection

In this study antigen independent factor in the pathogenesis of chronic rejection of organ transplants was examined. Kidney isografts and allografts were transplanted orthotopically into bilaterally nephroectomized rat recipients and studied functionally, morphologically and immunohistologically, at serial intervals up to 52 weeks after transplantation. Allograft recipients developed progressive proteinuria after 12 weeks, with gradual renal failure ultimately leading to death. At the same time, morphological changes, including progressive arteriosclerosis and glomerulosclerosis, tubular atrophy and interstitial fibrosis, developed. Immunohistologically, macrophages infiltrated glomeruli during this period and cytokines became unregulated. Our results showed that antigen independent functional and morphological changes occurred in long term kidney isografts and mimicked those appearing much earlier in allografts that reject chronically. Initial injury and extent of functioning renal mass is suggested to be important factor for such late changes.

To analyze the differentially expressed genes in chronic rejection after renal transplantation by bioinformatics

Objective: To use bioinformatics technology to analyse differentially expressed genes in chronic rejection after renal transplantation, we can screen out potential pathogenic targets associated with the development of this disease, providing a theoretical basis for finding new therapeutic targets. Methods: Gene microarray data were downloaded from the Gene Expression Profiling Integrated Database (GEO) and cross-calculated to identify differentially expressed genes (DEGs). Analysis of differentially expressed genes (DEGs) with gene ontology (GO) is a method used to study the differences in gene expression under different conditions as well as their functions and interrelationships, while Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis is a tool used to explore the functions and pathways of genes in specific biological processes. By calculating the distribution of immune cell infiltration, the result of immune infiltration in the rejection group can be analysed as a trait in Weighted Gene Co-Expression Network Analysis (WGCNA) for genes associated with rejection. Then, protein-protein interaction networks (PPI) were constructed using the STRING database and Cytoscape software to identify hub gene markers. Results: A total of 60 integrated DEGs were obtained from 3 datasets (GSE7392, GSE181757, GSE222889). By GO and KEGG analysis, the GEDs were mainly concentrated in the regulation of immune response, defence response, regulation of immune system processes, and stimulation response. The pathways were mainly enriched in antigen processing and presentation, EBV infection, graft-versus-host, allograft rejection, and natural killer cell-mediated cytotoxicity. After further screening using WGCNA and PPI networks, HLA-A, HLA-B, HLA-F, and TYROBP were identified as hub genes (Hub genes). The data GSE21374 with clinical information was selected to construct the diagnostic efficacy and risk prediction model plots of the four hub genes, and the results concluded that all four Hub genes had good diagnostic value (area under the curve in the range of 0.794-0.819). From the inference, it can be concluded that the four genes, HLA-A, HLA-B, HLA-F and TYROBP, may have an important role in the development and progression of chronic rejection after renal transplantation. Conclusion: DEGs play an important role in the study of the pathogenesis of chronic rejection after renal transplantation, and can provide theoretical support for further research on the pathogenesis of chronic rejection after renal transplantation and the discovery of new therapeutic targets through enrichment analysis and pivotal gene screening, as well as inferential analyses of related diagnostic efficacy and disease risk prediction.

Long-term liver allograft fibrosis:A review with emphasis on idiopathic post-transplant hepatitis and chronic antibody mediated rejection

Liver transplantation(LT)is a life-saving surgical procedure and the current standard of care for most patients with end stage liver disease.With improvements in organ preservation techniques,perioperative care,and immunosuppression,there is better patient and graft survival following LT,and assessment of the liver allograft in long-term survivors is becoming increasingly important.Recurrent or de novo viral or autoimmune injury remains the most common causes of chronic hepatitis and fibrosis following liver transplantation in adults.However,no obvious cause can be identified in many adults with controlled recurrent disease and the majority of pediatric LT recipients,as they have been transplanted for non-recurrent liver diseases.Serial surveillance liver biopsies post LT have been evaluated in several adult and pediatric centers to identify long-term pathological changes.Pathological findings are frequently present in liver biopsies obtained after a year post LT.The significance of these findings is uncertain as many of these are seen in protocol liver biopsies from patients with clinically good allograft function and normal liver chemistry parameters.This narrative review summaries the factors predisposing to long-term liver allograft fibrosis,highlighting the putative role of idiopathic post-LT hepatitis and chronic antibody mediated rejection in its pathogenesis.

Early detection of cardiac allograft vasculopathy and chronic rejection after heart transplantation-Report of one case

Objective To study clinically the feasibility of early diagnosis of cardiac allograft vascularopathy(CAV) and chronic rejection. Methods A 13-year-old female patient with dilated cardiomy-opathy received orthotopic heart transplantation for advanced heart failure, and subsequent immunosuppressive therapy including cyclosporine, prednisone and mofetil, and a mondily close follow-up. Coronary angiography and left ventricular endomyocardial biopsy (EMB) was perormed 9 months after the operation. Results The clinical and follow-up data of the case showed that cardiac or systemic nonspecific symptoms such as exertional chest discomfort, palpitation, fatigue or fever of unknown reasons were the first and ignorable clinical symptoms, and found disappeared after dosage addition of cyclinsporine, which indicated a early clinical manifestations of rejection or vasculopathy. While persistent sinus tachycardia on electrocadiogram, decreased left ventricular ejection fraction(from 64% -68% down to 47% - 50% ),

Mice aorta loop grafting: A new model which separate vascular rejection and neointimal formation in chronic rejection

Objective: To study the cause and mechanism of transplantation vasculopathy which characterized by accelerated graft arteriosclerosis (AGA), we established a mouse aorta graft model. Methods: A segment of thoracic aortas of B10.A (2R) mice were transplanted to C57BL/10 mice abdominal aorta by end to side anastomoses. The different time point collected grafts were analyzed by morphological, histochemical and electro microscopic methods. Results: Rejection was manifested as a concentric progressive destruction of the smooth muscle cells. In contrast, the endothelial inflammation and subsequent neointimal proliferation characteristic of AGA was localized to the regions of turbulent flow, i.e. the junction of the graft with the recipient aorta. Conclusion: This model separates the processes of rejection and neointimal formation which usually manifested together in the lesion of AGA, elucidate that different mechanisms control vascular rejection and neointimal formation in chronic rejection.

Depressant effect and mechanism of atorvastatin on the chronic rejection of aortic allograft in rats

Objective To investigate the depressant effect and mechanism of atorvastatin on the chronic rejection of aortic allograft in rats.Methods:The models of abdominal aorta transplantation were made with micro-surgery in rats. The recipients were divided into three groups:allograft control group,atorvastatin-treated group and isograft control group.Vascular intimal thickness in all of the groups were observed by histological examination.The expression of PCNA andα-SMA were determined by immunohistochemistry.The content of nitric oxide was determined by nitrate reductase chromatometry.Results:The vascular intimal thickness in rats of atorvastatin-treated group (11.60%±2.40%) were lower than those in allograft control group(34.60%±6.40%;P<0.05) and higher than those in isograft control group (1.15%±0.65%;P<0.05).The expression level of PCNA was decreased in atorvastatin-treated group (4.80%±0.80%)than allograft control group (18.40%±1.80%;P<0.05) and higher than isograft group (1.20%±0.40%; P<0.05).Conclusion:The expression of PCNA in the transplant aorta could be suppressed by atorvastafin,which re- suited in relief of chronic rejection of aortic allograft.

Chronic rejection after liver transplantation:Opening the Pandora’s box

Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy,CR still represents an important cause of graft injury,which might be irreversible,leading to graft loss requiring re-transplantation.To date,we still do not fully appreciate the mechanisms underlying this process.In addition to T cell-mediated CR,which was initially the only recognized type of CR,recently a new form of liver allograft CR,antibody-mediated CR,has been identified.This has indeed opened an era of thriving research and renewed interest in the field.Liver biopsy is needed for a definitive diagnosis of CR,but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation.Moreover,the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury,which should not be disregarded.Therapies for CR may only be effective in the“early”phases,and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage.Herein,we provide an overview of the current knowledge and research on CR,focusing on early detection,identification of non-invasive biomarkers,immunosuppressive management,re-transplantation and future perspectives of CR.

Efficacy of estradiol on preventing chronic kidney allograft rejection

hronic rejection is the main factor to result in the loss of renal allograft In order to look for a potential therapy chronic rejection, we investigated the efficacy of estradiol on preventing renal chronic rejection The kidneys of female F344 rats were orthotopically transplanted into ovatiectomized female Lewis rats and treated for 16 weeks with either estradiol or vehicle Compared with controls treated with vehicle, estradiol treatment reduced urinary protein excretion, glomerular sclerosis, interstitial infiltration and fibrosis, vascular lesions, in parallel to a reduced ICAM 1 and TGF β mRNA expression Our results suggested that estrodiol could significantly decrease the progression of chronic rejection, at least in female recipients, and the reduced adhesion molecule and TGF β gene expression may be involved in the mechanism for estradiol to prevent chronic rejection

Lymphocyte infiltration and activation in iris-ciliary body and anterior chamber of mice in corneal allograft rejection

AIM: To investigate the infiltration and activation of lymphocyte in iris-ciliary body and anterior chamber after allogenic penetrating keratoplasty (PK), for further revealing the role of iris-ciliary body in corneal allograft immune rejection. METHODS: In the mice models of PK, BALB/C mice received orthotopic isografts (n =35) or C57BL/6 donor allografts (n=25). Grafts were examined daily for 3 weeks by slit-lamp microscopy and scored for opacity. The infiltration of CD4(+) T lymphocyte in iris-ciliary body and anterior chamber was examined by immunohistology and the mRNA of CD80 and CD86 in both cornea graft and iris-ciliary body by RT-PCR was analyzed in allograft recipient at days 3, 6, 10 and the day when graft rejection occurred. Isograft recipients were examined as control at the corresponding time points. Transmission electron microscope was used to study the ultrastructure, especially cell infiltration, of iris-cilary body and corneal graft at day 3, 7 and the day when rejection occurred after allogenic PK. RESULTS: Rejection was observed in all the allograft recipients followed more than 10 days, at a median time of 15 days (range 12-18 days), but not in any of isografts. CD4(+) T cells were first detected at day 6 after transplantation in limbus and Ciliary body, and then in the stroma of recipient, iris, anterior chamber and corneal allograft with an increased number until graft rejection occurred. CD80 and CD86 mRNA were detected under RT-PCR examination in both graft and iris-ciliary body of allograft recipient, but not in any of isograft recipient. Three days after operation, lymphocytes and monocytes macrophages were visible in iris blood vessels and the anterior chamber, and vascular endothelial cell proliferation and activation were significant under transmission electron microscopy examination. At day 7, corneal endothelial cells became thinner. Lymphocytes and mononuclear macrophages were found with great number in the anterior chamber and adhered to the corneal endothelium. Blood vessels in iris increased and were filled with lymphocytes. And lymphocytes were detected to migrate through endothelial cell gap out of vessels. When allograft rejection occurred, macrophages attached to endothelial cells with large number of lymphocytes and macrophages infiltrating in iris. CONCLUSION: Lymphocyte infiltration and activation occurred in iris-ciliary body after allogenic PK, and the lymphocytes could migrate from iris blood vessel to the anterior chamber, which might play an important role in corneal allograft immune rejection.

Biology of chronic graft-vs-host disease:Immune mechanisms and progress in biomarker discovery

Chronic graft-vs-host disease(c GVHD) is the leading cause of long-term morbidity and mortality following allogeneic hematopoietic stem cell transplantation. It presents as a chronic inflammatory and sclerotic autoimmune-like condition that most frequently affects the skin, oral mucosa, liver, eyes and gastrointestinal tract. Both clinical and animal studies have shown that multiple T cell subsets including Th1, Th2, Th17, T follicular helper cells and regulatory T-cells play some role in cG VHD development and progression; B cells also play an important role in the disease including the production of antibodies to HY and nuclear antigens that can cause serious tissue damage. An array of cytokines and chemokines produced by different types of immune cells also mediate tissue inflammation and damage of cG VHD target tissues such as the skin and oral cavity. Many of these same immune regulators have been studied as candidate cG VHD biomarkers. Recent studies suggest that some of these biomarkers may be useful for determining disease prognosis and planning long-term clinical followup of cG VHD patients.

Molecular and cellular pathways involved in the therapeutic functions of MHC molecules;a novel approach for mitigation of chronic rejection

The mutated major histocompatibility complex (MHC) class I that contains donor-type epitopes displayed on recipient-type molecule was show- n to inhibit acute and chronic rejection and in-duce indefinite survival of heterotopic cardiac allografts when administered in combination with a sub-therapeutic dose of cyclosporine (CsA) in a rat transplantation model. To eluci-date the molecular pathways involved in the immunosuppressive effects of the mutated MHC molecule, we analyzedgene and protein expres-sion profile during early and late phase follow-ing post-transplantation. Cytoskeletal structure analysis and expression status of Rho GTPase proteins, vacuolar transport and cytoskeleton regulatory pathways involved in immune re-sponse in T and dendritic cells demonstrated the novel mechanism for the abrogation of chronic rejection. Our studies confirm a new role of Rho GTPase pathway in the modification of T cell motility and infiltration of the graft. We discuss these results within the framework of the most recent literature on MHC and molecu-lar machinery controlling T cell functions and dendritic cell antigen presentation.

Rock1 Inhibitor Abrogates Chronic Rejection in Rat Cardiac Model System

Background: We have shown previously that the abrogation of acute and chronic rejection of rat cardiac allografts occurs through the down-regulation of RhoA pathway and involves the changes in RhoA kinase (ROCK)-dependent actin cytoskeleton and T cell motility. Here we studied the ability of the Y-27632, a highly selective inhibitor of Rho-associated protein kinase p160ROCK (ROCK1), to abrogate chronic rejection of the allograft and influence T cell infiltration. Methods: Heterotopic cardiac transplants were performed between donor Wistar Furth (WF) and ACI recipient rats. Controls received sub-therapeutic dose of cyclosporine (CsA, 10 mg/kg) for 3 days or 7 days therapeutic dose of cyclosporine. The experimental groups of ACI recipient received one preoperative dose of the Y-27632 inhibitor (2 mg/kg, gavage feed) in conjunction with the sub-therapeutic dose of CsA for 3 days or inhibitor alone for 7 days. The cardiac grafts were harvested at 100 days of post-transplantation for histological and immunohistochemical assessment of chronic rejection, vascular sclerosis, and infiltration by different T cell subtypes. Results: Cardiac allografts from recipients exposed to Y-27632 inhibitor in conjunction with sub-therapeutic dose of CsA showed drastically reduced vascular sclerosis, minimal myocardial total cellular infiltration, and were selectively infiltrated with Foxp3+ T regulatory (Treg) cells. Conclusions: Our novel finding that a single dose of the ROCK1 inhibitor Y-27632 attenuates chronic rejection in rat cardiac model system by promoting development of Treg cells warrants its potential as a novel therapeutic agent specific for the inhibition of chronic rejection.

Long-term outcomes of pediatric liver transplantation in acute liver failure vs end-stage chronic liver disease:A retrospective observational study

BACKGROUND Children with acute liver failure(ALF)who meet the criteria are eligible for super-urgent transplantation,whereas children with end-stage chronic liver disease(ESCLD)are usually transplanted electively.Pediatric liver transplantation(PLT)in ALF and ESCLD settings has been well described in the literature,but there are no studies comparing the outcomes in these two groups.AIM To determine if there is a difference in post-operative complications and survival outcomes between ALF and ESCLD in PLT.METHODS This was a retrospective observational study of all primary PLTs performed at a single center between 2000 and 2019.ALF and ESCLD groups were compared for pretransplant recipient,donor and operative parameters,and post-operative outcomes including graft and patient survival.RESULTS Over a 20-year study period,232 primary PLTs were performed at our center;195 were transplanted for ESCLD and 37 were transplanted for ALF.The ALF recipients were significantly older(median 8 years vs 5.4 years;P=0.031)and heavier(31 kg vs 21 kg;P=0.011).Living donor grafts were used more in the ESCLD group(34 vs 0;P=0.006).There was no difference between the two groups concerning vascular complications and rejection,but there were more bile leaks in the ESCLD group.Post-transplant patient survival was significantly higher in the ESCLD group:1-,5-,and 10-year survival rates were 97.9%,93.9%,and 89.4%,respectively,compared to 78.3%,78.3%,and 78.3%in the ALF group(P=0.007).However,there was no difference in 1-,5-,and 10-year graft survival between the ESCLD and ALF groups(90.7%,82.9%,77.3%vs 75.6%,72.4%,and 66.9%;P=0.119).CONCLUSION Patient survival is inferior in ALF compared to ESCLD recipients;the main reason is death in the 1st year post-PLT in ALF group.Once the ALF children overcome the 1st year after transplant,their survival stabilizes,and they have good long-term outcomes.

Mycophenolate Mofetil with Low Dose CsA for Chronic Rejection in Primary Cadaveric Renal Recipients

Objective To investigate the clinical efficacy of mycophenolate mofetil(MMF) with low dose CsA for chronic rejection in primary cadaveric renal recipients. Methods A total of 8 renal recipients who were clinically diagnosed as chronic rejection were given triimmunosuppressive agents: MMF 1.5~2.0 g/d+ CsA 2 to 3 mg/kg·d -1 and pred 10 mg/d.Results Blood creatinine reduced to normal level and urine protein disappeared in five cases, blood creatinine and urine protein decreased obviously in two cases, and kidney function deteriorated in another patient 4 to 9 weeks after this strategy. No acute rejection episodes or liver damage occurred among these patients during treatment. White blood cells reduced in one case, but it improved after therapy. Conclusion MMF combined with low dose CsA can bring a considerable efficacy in reversing chronic rejection of renal recipients. This immunosuppressive strategy may be a useful routine in the treatment of chronic rejection.

Chronic allograft rejection:A significant hurdle to transplant success

The state-of-the-art immunosuppression drugs do not ensure indefi nite transplant survival,and most transplants are continuously lost to chronic rejection even years posttransplantation.This form of rejection is responsible for long-term failure of transplanted organs.The mechanisms involved in development of chronic rejection are not well-understood.One of the main features of chronic rejection is progressive luminal narrowing of graft vessels,which results in compromised blood flow,ischemia,cell death,and finally graft failure.All the existing immunosuppressive regimens are targeting acute rejection,and at present there is no available therapy for prevention of chronic rejection.Chronic rejection involves two major,but interrelated responses:The first is the host immune response against the transplant mediated primarily by alloreactive T and B cells,and the second is injury and repair of the graft(vasculopathy of graft vessels).Here we focus on recent advances in understanding the cellular and molecular aspects of chronic transplant vasculopathy and function of macrophages,topics pivotal for development of novel antichronic rejection therapies.

Treatment with plasmapheresis, immunoglobulins and rituximab for chronic-active antibody-mediated rejection in kidney transplantation: Clinical, immunological and pathological results

AIM To evaluate the role of a therapeutic regimen with plasma exchange, intravenous immunoglobulins and rituximab in chronic-active antibody-mediated rejection(c AMR) settings.METHODS We compared 21 kidney transplant recipients(KTRs) with a diagnosis of c AMR in a retrospective casecontrol analysis: nine KTRs treated with plasmapheresis, intravenous immunoglobulins and rituximab(PE-IVIGRTX group) vs 12 patients(control group) not treated with antibody-targeted therapies. We examined kidney survival and functional outcomes 24 mo after diagnosis. Histological features and donor-specific antibody(DSA) characteristics(MFI and C1 q-fixing ability) were also investigated.RESULTS No difference in graft survival between the two groups was noted: three out of nine patients in the PE-IVIG-RTX group(33.3%) and 4/12 in the control group(33.3%) experienced loss of allograft function at a median time after diagnosis of 14 mo(min 12-max 18) and 15 mo(min 7-max 22), respectively. Kidney functional tests and proteinuria 24 mo after cA MR diagnosis were also similar in both groups. Only microvascular inflammation(glomerulitis + peritubular capillaritis score) was significantly reduced after PE-IVIG-RTX in seven out of eight patients(87.5%) in the PE-IVIG-RTX group(median score 3 in pre-treatment biopsy vs 1.5 in post-treatment biopsy; P = 0.047), without any impact on kidney survival and/or DSA characteristics. No functional or histological parameter at diagnosis was predictive of clinical outcome.CONCLUSION Our data showed no difference in the two year posttreatment outcome of kidney grafts treated with PE-IVIGRTX for c AMR diagnosis, however there were notable improvements in microvascular inflammation in posttherapy protocol biopsies. Further studies, especially involving innovative therapeutic approaches, are required to improve the management and long-term results of this severe condition.

Preservation of donor's heart and lung and discrimination and postoperative immunotherapy of graft rejection:a report of 2 cases of heart-lung transplantation

Objective To summarize preservation measures of donor’s heart and lung,and postoperative imrnunotherapy,as well as clinical experience of discrimination and management for graft rejection. Methods Clinical data of 2 cases of heart - lung transplantation in our depart-