Ipsilateral Lymphadenectomy to Inhibit Corneal Allograft Rejection in Rats

In order to investigate the ipsilateral lymphadenectomy for inhibiting rejection in rat corneal transplantation, corneal allogenic transplantation models were established in rats. Eighteen female Wister rats were used as donors, and 36 Sprague Dawley rats as recipients. After penetrating corneal transplantation, recipients were randomly divided into 3 groups: group A (control group); group B, the ipsilateral lymphadenectomy group; group C, the bilateral lymphadenectomy group. Among 12 rats in each group, the corneas of 2 rats in each group were used for pathological study at day 14 after the transplantation, and the remaining 10 rats were used for studying corneal rejection by a slit lamp. The time points when allograft rejection occurred were recorded and mean survival time (MST) was compared. The results showed that MST in groups B and C was 46 30±9 464 days and 44 43±7 604 days, respectively, which was significantly prolonged as compared with that in group A (10 71±1 567 days, P<0.01). There was no significant difference in MST between groups B and C (P>0.05). It was concluded that both bilateral and ipsilateral lymphadenectomy therapies could effectively inhibit the corneal allograft rejection. Ipsilateral lymphadenectomy is a less complex surgical procedure and is just as effective in preventing rejection.

NF-kB in allograft rejection

Nuclear factor-kappa B (NF-kB) as an essential transcription factor in the control of expression of the cytokine-induced genes in immune and inflammatory responses regulates cytokines in allograft rejection. In this review, we summarize the general properties of NF-kB and the principal findings to shed new light on transplantation.

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

SAHA, an HDAC inhibitor, synergizes with tacrolimus to Prevent murine cardiac allograft rejection

Suberoylanilide hydroxamic acid （SAHA）, as a histone deacetylase （HDAC） inhibitor （HDACi）, was recently found to exhibit an immunosuppressive effect. However, whether SAHA can synergize with calcineurin inhibitors （CNIs） to inhibit allograft rejection and its underlying mechanism remain elusive. In this study, we demonstrated the synergistic effects of SAHA and non-therapeutic dose of tacrolimus （FK506） in prolonging the allograft survival in a murine cardiac transplant model. Concomitant intragraft examination revealed that allografts from SAHA-treated recipients showed significantly lower levels of IL-17 expression, and no discernable difference for IL-17 expressions was detected between SAHA- and SAHA/FK506-treated allograft as compared with allografts from FK506-treated animals. In contrast, administration of FK506 significantly suppressed interferon （IFN）-y but increased IL-IO expression as compared with that of SAHA-treated animals, and this effect was independent of SAHA. Interestingly, SAHA synergizes with FK506 to promote Foxp3 and CTLA4 expression. In vitro, SAHA reduced the proportion of Th17 cells in isolated CD4＋ T-cell population and decreased expressions of IL-17A, IL-17F, STAT3 and RORyt in these cells. Moreover, SAHA enhances suppressive function of regulatory T （Treg） cells by upregulating the expression of CTLA-4 without affecting T effector cell proliferation, and increased the proportion of Treg by selectively promoting apoptosis of T effector cells. Therefore, SAHA, a HDACi, may be a promising immunosuppressive agent with potential benefit in conjunction with CNI drugs.

A proteomic analysis of allograft rejection in rats after liver transplantation

In order to understand the allograft rejection in orthotopic liver transplantation (OLT), an allograft re- jection rat model was established and studied by proteomic approach. The protein expression profiles of liver tissues were acquired by fluorescence two-dimensional difference gel electrophoresis (2D DIGE) that incorporated a pooled internal standard and reverse fluorescent labeling method. The expression levels of 27 protein spots showed significant changes in acute rejection rats. Among these spots, 19 were identified with peptide mass fingerprinting using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) after tryptic in-gel digestion. The results of the present paper could be helpful for our better understanding of allograft rejection in organ transplantation.

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

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% ),

Gene transfer of huCTLA4-Ig to inhibit the acute rejection of liver allograft in rats

To observe the effect of gene transfer of huCTLA4-Ig to inhibit the acute rejection of liver allograft in rats.Methods With AdEasy vector system,the recombinant adenovirus containing huCTLA4-Ig gene was constructed.Using ex vivo gene transfer technique,exogenous gene was introduced to the liver graft during cold preservation and expressed locally in the graft.The effect of inhibition of acute rejection and inducing liver graft tolerance was observed.Results No recipients in group A (without any treatment,n=5) or group B (treated with Ad-GFP,n=4) died within 3 weeks after transplantation and severe acute rejection (massive periportal infiltration,endothelilitis,damage to biliary epithelium and severe tissue destruction) was confirmed pathologically in the graft.In contrast,all recipients in group C (treated with Ad-huCTLA4-Ig,n=5) achieved long-term liver allograft survival (>150 days).Histological examination of Ad-huCTLA4-Ig transduced allografts demonstrated a mild to moderate periportal inflammation and mild injury to liver graft on day 8 posttransplant.A mild mononuclear infiltration was observed;however,there was complete preservation of the bild ducts and no evidence of vascular injury on day 150 posttransplant.The mean IL-2 concentration in serum was (362.09±45.84) ng/L at day 1 pretransplant.In control animals (groups A and B),serum IL-2 concentration was elevated to a high level within 7 days posttransplant,which was about 1.5 to 2.5 times as much as that before transplant.In contrast,in huCTLA4-Ig-treated animals (groups C),IL-2 concentration in serum was maintained at a relative low level,which was near or less than that before transplant (P<0.01).Conclusion Using ex vivo gene transfer technique,huCTLA4-Ig gene can be introduced to the liver graft during cold preservation.The modified graft can express and excrete immunoregulatory protein locally,which can suppress acute alloimmune response and is responsible for prolongation of graft survival without using routine immunosuppressive drugs.These findings provide some experimental evidence that gene delivery of sequences encoding immunoregulatory proteins can be applied to clinical liver transplantation for inhibiting the acute alloimmune response and achieving graft tolerance.7 refs,2 tabs.

Immunology demystified: A guide for transplant hepatologists

Liver transplantation has become standard practice for treating end-stage liver disease.The success of the procedure relies on effective immunosuppressive medications to control the host's immune response.Despite the liver's inherent capacity to foster tolerance,the early post-transplant period is marked by significant immune reactivity.To ensure favorable outcomes,it is imperative to identify and manage various rejection types,encompassing T-cell-mediated,antibody-mediated,and chronic rejection.However,the approach to prescribing immunosuppressants relies heavily on clinical judgment rather than evidencebased criteria.Given that the majority of patients will require lifelong immunosuppression as the mechanisms underlying operational tolerance are still being investigated,healthcare providers must possess an understanding of immune responses,rejection mechanisms,and the pathways targeted by immunosuppressive drugs.This knowledge enables customization of treatments and improved patient care,even though a consensus on an optimal immunosuppressive regimen remains elusive.

Effect of Emodin in Suppressing Acute Rejection Following Liver Allograft Transplantation in Rats

Objective：To investigate the mechanism of action of emodin for suppressing acute allograft rejection in a rat model of liver transplantation.Methods：Brown Norway（BW） recipient rats of orthotopic liver transplantation（OLT） were divided into three groups,Group A receiving isografting（with BW rats as donor）, Group B receiving allografting（with Lewis rats as donor）,Group C receiving allografting and emodin treatment （50 mg/kg daily）.They were sacrificed on day 7 of post-transplantation,and their hepatic histology,plasma cytokine levels,and T-cell subset expression were detected.Results：Compared with those in Group A,rats in Group B exhibited severe allograft rejection with a rejection activity index（RAI） of 7.67±0.98,extensive hepatocellular apoptosis with an apoptosis index（Al） of 35.83±2.32,and elevated plasma levels of interleukin-2 （IL-2）,interleukin-10（IL-10）,tumor necrosis factor-α（TNF-α）,CD4^＋ and CD4^＋/CD8^＋ ratio.However,recipients in Group C showed a decrease in histological grade of rejection and hepatocellular apoptosis,as well as a decrease in plasma levels of IL-2,TNF-α,CD4^＋ and CD4^＋/CD8^＋ ratio,but elevated levels of IL-10 as compared with the allograft group.Conclusion：Post-OLT acute rejection could be attenuated by emodin,its mechanism of action may be associated with protecting hepatocytes from apoptosis,polarizing the Th 1 paradigm to Th2,and inhibiting the proliferation of CD4^＋ T cell in plasma.

DETECTION OF CYTOMEGALOVIRUS(CMV) IMMEDIATE EARLY ANTIGEN IN KIDNEY BIOPSIES AND TRANSPLANT NEPHRECTOMIES

Objective To investigate the relationship between CMV infection and renal allograft rejection. Methods 39 kidney biopsies and transplant nephrectomies were collected and investigated for CMV immediate early antigen by immunohistochemistry. Results In 14 out of 39 tissue specimens CMV immediate early antigen were found. 8 biopsies from normal donor kidneys were negative; only 1 (10%) in 10 tissue specimens with early stage acute rejection was positive; 5(55.6%) in 9 biopsies with late stage acute rejection and 8 (66.7%) in 12 tissue blocks with chronic rejection were positive. Compared with normal kidney tissues, the infections in tissues with early stage acute rejection didn't increase obviously, but increased obviously in kidney tissue specimens with late stage rejection and with chronic rejection (P< 0.05). Conclusion CMV infection appears to contribute to late stage acute rejection and chronic rejection after renal transplantation.

Review of heart transplantation from hepatitis C-positive donors

Significant scarcity of a donor pool exists for heart transplantation(HT)as the prevalence of patients with end-stage refractory heart failure is increasing exceptionally.With the discovery of effective direct-acting antiviral and favorable short-term outcomes following HT,the hearts from hepatitis C virus(HCV)patient are being utilized to increase the donor pool.Short-term outcomes with regards to graft function,coronary artery vasculopathy,and kidney and liver disease is comparable in HCV-negative recipients undergoing HT from HCVpositive donors compared to HCV-negative donors.A significant high incidence of donor-derived HCV transmission was observed with great success of achieving sustained viral response with the use of direct-acting antivirals.By accepting HCV-positive organs,the donor pool has expanded with younger donors,a shorter waitlist time,and a reduction in waitlist mortality.However,the longterm outcomes and impact of specific HCV genotypes remains to be seen.We reviewed the current literature on HT from HCV-positive donors.

Lymphangiogenesis Occurring in Transplanted Corneas

To study corneal lymphangiogenesis after corneal transplantation, corneal allogenic transplantation models were established in rats. 8 female Wister rats were used as donors, and 16 Sprague Dawley （SD） rats were used as recipients and 2 SD served as controls. Corneal lymphangiogenesis and hemangiogenesis was examined by electron microscopy 1 and 2 weeks after corneal penetrating transplantation, and the expression of lymphatic vessel endothelial receptor （LY- VE-1） was examined 1, 3, 7, 14 days after the transplantation respectively. In addition, 19 allograft failed human corneas were examined by 5＇-nase-alkaline phosphatase （5＇-NA-ALP） doubleenzyme-histochemistry staining to detect corneal lymphangiogenesis and hemangiogenesis. By immunohistochemistry for LYVE-1, it was found that blown lymphatics were localized in the stroma 3 days after the corneal transplantation. With electron microscopy, new lymphatic vessels and blood vessels were found 1 and 2 weeks after the corneal transplantation. By 5＇-NA-ALP enzyme-histochemistry, corneal hemangiogenesis was found in all allograft failed human corneas and 5 of 19 （26.3 % ） cases had developed corneal lymphangiogenesis. It is concluded that corneal lymphangiogenesis is present after corneal transplantation, which may play an important role in allograft rejection.

Post-transplant plasma cell hepatitis in a liver transplant patient treated with pegylated interferon plus ribavirin

The recurrence of hepatitis C after a liver transplant remains an important cause of graft loss and retransplant. Antiviral therapy with peginterferon plus ribavirin (PEG-INF/RBV) can achieve a sustained viral response and histological improvement in a high percentage of cases. However, this treatment is not exempt from important side effects or from the possibility of precipitating rejection, with the resulting graft loss. We report the case of a liver transplant patient who received treatment with PEG-INF/RBV and developed plasma cell hepatitis as the presenting form of rejection.

Anti-CD25 monoclonal antibody modulates cytokine expression and prolongs allografts survival in rats cardiac transplantation

Objective To investigate the role of anti- interleukin-2 receptor(CD25) monoclonal antibody in the regulation of cytokine mRNA expression of IL-1β, IL-2, CD25, IL-4, IL-5, IL-6, IL-10, tumour necrosis factor-α (TNFα), and interferon-γ (IFNγ) in cardiac allografts to elucidate its immunological mechanism and role in rats that have undergone cardiac transplantation. Methods These in vivo studies were conducted using a rat MHC mismatch SD to Wistar heterotopic cardiac transplant model. Simulect, an anti-CD25 antibody, was used to prevent allograft rejection. An increase in the rate of allograft survival was observed. Rats were sacrificed on day 1, 3, 5, 7, 9, 11, 14 post-transplantation and hearts were harvested for furgher study. Cytokine mRNA expression was determined by semiquantitative RT-PCR. Results In the control group, cardiac allografts were rejected at 8.3±1.7 days after transplantation (±s). The rats who received CsA rejected the cardiac allograft at 26.4±5.7 days post-transplant. Allograft survival of Simulect-treated rats was 29.2±7.1 days (P<0.05 vs controls). Rats treated with simulect and CsA had the longest survival of 55.0±11.6 days (P<0.001 vs controls). CD25 mRNA expression in the heart tissue samples of treated rats was undetectable or very weak. However, the untreated group, CD25 expression increased, although anti-CD25 decreased this CD25 expression in the heart graft. Furthermore, in untreated allografts, IL-2, TNFα and IFN-γ were strongly expressed, an effect that markedly decreased after simulect treatment. Finally, IL-4, IL-5, IL-6 and IL-10 expression was strong in anti-CD25-treated allografts. Conclusions These results suggest that anti-CD25 antibody treatment may not only neutralize CD25 activity but also play a role in altering cytokine mRNA expression and prolong the survival of allografts.

Interleukin-1 receptor antagonist eye drops promoting high-risk corneal allografts survival in rats

Background Immune rejection is the main reason of grafts failure after corneal transplantation. This study was to determine whether interlerkin-1 receptor antagonist (IL-1ra) eye drops could prolong corneal allografts survival in high-risk corneal orthotopic allotransplantation in rat model and to study the effect of IL-1ra on the expression of CD 1-positive cells in the grafts Methods For all experiments, the Sprague-Dawley (SD) rats' corneas were transplanted into Wistar rats' eyes High-risk transplants included those that had been sutured into Wistar recipient beds with corneal neovascularization induced by placement of three interrupted sutures in the host cornea 7 days earlier All the animals were divided, in a masked fashion, into three treatment groups and one control group Each treatment group received IL-1ra eye drops of different concentrations (1 mg/ml, 3 mg/ml, or 5 mg/ml, respectively) four times a day for 30 days The control group received 0 9% normal saline (NS) eye drops in the same way as the treatment groups All allografts were evaluated for signs of rejection from the first day after surgery Ten days later, corneal specimens were processed to examine the expression of CD 1-positive cells and histopathological changes Results The survival time of the transplants was 5 80±0 79, 5 89±1 05, 6 78±0 83, and 9 00±2 36 days respectively in the control or three treatment groups Compared with the control group, 1 mg/ml IL-1ra eye drop did not prolong the survival time of the allografts ( t =0 210, P >0 05) However, 3 mg/ml and 5 mg/ml IL-1ra eye drop did prolong the survival time of the grafts ( t ≥2.627, P <0 05), with the latter showing more obvious effect Immunohistochemical examinations showed a significant decrease in inflammatory cell and CD 1-positive cell infiltration in IL-1ra treated groups compared with the control group Conclusions IL-1ra can promote corneal allograft survival in a dose-dependant manner by reducing the infiltration of CD 1-positive cells in high-risk corneal transplantation