The interleukin-17 G-197A polymorphism is associated with cyclosporine metabolism and transplant rejection in liver transplant recipients

The role of the indoleamine 2,3-dioxygenase gene in preventing ovarian transplant rejection in rats†

Indoleamine 2,3-dioxygenase (IDO) plays important roles in maternal immune tolerance. Female Sprague Dawley rats (9-11 weeks old) were randomly divided into an autoplastic transplantation group (n = 75) and an allograft transplantation group (n = 300) was further divided into subgroups of ovarian transplantation, allograft ovarian transplantation, allograft ovarian transplantation with cyclosporine A treatment, allograft ovarian transplantation and transfection with IDO-expressing lentiviruses, and allograft ovarian transplantation and transfection with control lentiviruses. IDO was successfully transfected into the transplanted ovarian tissue. The survival rate, success rate of ovarian transplantation, period until estrous cycle restoration, and estrogen levels of rats that received IDO-expressing lentiviruses were significantly different from those of rats that underwent allograft transplantation and with control transfection (all P < 0.05), but not significantly different from those rats that received autoplastic transplantation (all P > 0.05). The number of ovarian follicles in the transplanted ovarian tissue of rats that received IDO-expressing lentiviruses was also significantly higher. The expression level of IDO protein detected by immunohistochemistry and western blotting was especially high in ovaries that had received IDO-containing lentiviruses. Naturally pregnant rats were found in each group postoperatively. These results indicated that IDO-expressing lentiviruses were successfully transfected into transplanted ovarian tissues of rats and that IDO was stably expressed within a certain time. These findings suggest that the expression level of IDO protein is associated with an enhanced success rate of ovarian tissue transplantation and a short restoration period of endocrine function.

Cytokines in Liver Transplantation

Cytokines, soluble mediators of the immune system, play a critical role in the pathogenesis of autoimmune, allergic and infectious diseases. They are also implicated in the initiation and development of allograft rejection. During recent years, there have been considerable advances in generating novel anti-cytokine agents with promoted efficacy and safety, which could be administrated for managing dysregulated cytokine secretion; besides, gene therapy for overexpression of immunomodulatory cytokines has shown substantial improvements. Liver transplantation has been established as a life-saving treatment for end-stage hepatic diseases but the growing number of recipients urge for improved post-transplant care including tolerance induction, infection control and resolving immunosuppressant drugs adverse effects. Cytokines with a wide range of proinflammatory and regulatory properties might be considered as potential therapeutic targets for selective suppression or enhancement of the immune responses in recipients. In the present review, we aimed to summarize the positive and negative effects of cytokines on liver allograft in addition to their prognostic and therapeutic values.

Genomics and Liver Transplantation: Genomic Biomarkers for the Diagnosis of Acute Cellular Rejection

Acute cellular rejection (ACR) is a common complication in liver transplantation recipients (LTRs), especially within the first 12 months, and it is associated with increased morbidity and mortality. Although abnormalities in standard liver biochemistries may raise the clinical suspicion for ACR, it lacks specificity, and invasive liver biopsies, which are associated with numerous risks, are required for definitive diagnoses. Biomarker discovery for minimally invasive tools for diagnosis and prognostication of ACR after liver transplantation (LT) has become a rapidly evolving field of research with a recent shift in focus to omics-based biomarker discovery. Although none are yet ready to replace the standard of care, there are several promising minimally invasive, blood-derived biomarkers that are under intensive research for the diagnosis of ACR in LTRs. These omics-based biomarkers, encompassing DNA, RNA, proteins, and metabolites, hold tremendous potential. Some are likely to become integrated into ACR diagnostic algorithms to assist clinical decision making with a high degree of accuracy that is cost-effective and reduces or even obviates the need for an invasive liver biopsy.

Substrate-independent polymer coating with stimuli-responsive dexamethasone release for on-demand fibrosis inhibition

Tissue fibrosis caused by implantation of tissue engineering scaffolds is an urgent problem in clinical research. In this work, a substrate-independent coating with on-demand release of an antifibrotic drug has been fabricated to effectively address this issue. This coating was formed through a substrate-independent layer-by-layer (LBL) technique via a cationic polyelectrolyte (poly-diallyldimethylammonium, PDDA) and an anionic polyelectrolyte (poly-styrenesulfonate, PSS), where parts of PSS and PDDA were physically replaced by carboxyl functionalized polyethylene glycol grafted onto antifibrotic drug dexamethasone (DEX-PEG-COOH). Considering the easy generation of local inflammation after implantation, an ester bond was designed between PEG-COOH and DEX. Therefore, the overexpressed esterase under inflammatory conditions hydrolyzes the ester bond and thereby releases DEX from the film to inhibit fibrosis occurring in the tissue repair process. The in vivo capacity of this coating to restrain tissue fibrosis was investigated by a skin defect model using porous polycaprolactone (PCL) scaffolds as substrates. The experimental results showed that the fibrosis-related proteins (Col-I, TGF-β and fibronectin) and the infiltration of myofibroblasts (α-SMA) of skin tissues in the coated PCL scaffold group were significantly lower than those in the blank control group and pure PCL scaffold group. Moreover, the histological evaluations showed that the coating group could significantly decrease the deposition of collagen and meanwhile promote the partial regeneration of skin appendages. These results successfully demonstrate that the universal coating prepared with a simple protocol would be an effective strategy to address the fibrosis issues during tissue engineering.

Importance of genetic polymorphisms in liver transplantation outcomes

Although, liver transplantation serves as the only curative treatment for patients with end-stage liver diseases, it is burdened with complications, which affect survival rates. In addition to clinical risk factors, contribution of recipient and donor genetic prognostic markers has been extensively studied in order to reduce the burden and improve the outcomes. Determination of single nucleotide polymorphisms (SNPs) is one of the most important tools in development of personalized transplant approach. To provide a better insight in recent developments, we review the studies published in the last three years that investigated an association of recipient or donor SNPs with most common issues in liver transplantation: Acute cellular rejection, development of new-onset diabetes mellitus and non-alcoholic fatty liver disease, hepatocellular carcinoma recurrence, and tacrolimus concentration variability. Reviewed studies confirmed previously established SNP prognostic factors, such as PNPLA3 rs738409 for non-alcoholic fatty liver disease development, or the role of CYP3A5 rs776746 in tacrolimus concentration variability. They also identified several novel SNPs, with a reasonably strong association, which have the potential to become useful predictors of post-transplant complications. However, as the studies were typically conducted in one center on relatively low-to-moderate number of patients, verification of the results in other centers is warranted to resolve these limitations. Furthermore, of 29 reviewed studies, 28 used gene candidate approach and only one implemented a genome wide association approach. Genome wide association multicentric studies are needed to facilitate the development of personalized transplant medicine.

FK506 combined with GM6001 prevents tracheal obliteration in a mouse model of heterotopic tracheal transplantation

BACKGROUND

Obliterative bronchiolitis (OB) is the major complication limiting the long-term survival of allografts after lung transplantation. In this study, we investigated the effect of tacrolimus (FK506) combined with GM6001，a matrix metalloproteinase (MMP) inhibitor， on the formation of OB using a mouse heterotopic tracheal transplantation model.

METHODS

Syngeneic tracheal grafts were transplanted heterotopically from BALB/c mice to BALB/c mice. Allografts from C57BL/6 mice were transplanted to BALB/c mice. Isograft group, allograft group, allograft+FK506 group, allograft +GM6001 group and allograft+FK506 + GM6001 group was given respectively intraperitoneal injection of saline, saline, FK506, GM6001 and FK506 + GM6001 once a day. At 28 day after transplantation, OB incidence was determined by hematoxylin-eosin staining and the expressions of MMPs and cytokines were assessed using enzyme linked immunosorbent assay, immunohistochemical assays and western blot assay.

RESULTS

The tracheal occlusion rates of isograft group, allograft group, allograft+FK506 group, allograft+GM6001 group and allograft+FK506 + GM6001 group were 0, 74.1 ± 9.79%, 34.4 ± 6.04%, 40.3 ± 8.77% and 26.5 ± 5.73% respectively. There were significant differences between the latter two groups (P < .001). The serum MMP-8 and MMP-9 levels of allograft group were significantly higher than those of isograft group (P < .05) and had no significant decrease when treated by FK506. The serum MMP-8 and MMP-9 levels of allograft+FK506 + GM6001 group were significantly lower than those of allograft+FK506 group (P < .05). MMP-8 and MMP-9 protein expression in the grafts of allograft+FK506 + GM6001 group were lower than those of allograft+FK506 group verified by immunohistochemical staining and western blotting.

CONCLUSION

FK506 combined with GM6001 could alleviate tracheal obliteration in mouse heterotopic tracheal transplantation model, due to its inhibitory effect on MMPs.