Blockade of γc Signals in Combination with Donor-specific Transfusion Induces Cardiac Allograft Acceptance in Murine Models

The γc cytokines play an important role in proliferation and survival of T cells. Blocking the γc signals can cause the activated donor-reactive T cells losing the ability to proliferate, and getting into apoptosis pathway, which contributes to induction of the peripheral tolerance. In this study, we induced the transplant tolerance through blocking the γc in combination with donor-specific transfusion (DST) in the cardiac transplantation. Following DST, on the day 2, 4 and 6, C57BL/6 recipients received anti-γc monoclonal antibodies (mAbs) injection, and those in control group were not given anti-γc mAbs. On the day 7, Balb/c cardiac allografts were transplanted. All recipients in experimental group accepted cardiac allografts over 30 days, and two of them accepted allografts without rejection until sacrifice on the 120 day. Animals only receiving DST rejected grafts within 5 days, and the mice receiving cardiac transplantation alone rejected grafts within 9 days. Our study showed that blockade of γc signaling combined with DST significantly prolonged allograft survival, which was probably associated with inhibition of antigen-specific T-cell proliferation and induction of apoptosis.

Role of Oxidative Stress in Cardiac Allograft Vasculopathy

Cardiac Allograft Vasculopathy, an accelerated form of arterial occlusive disease, is the major cause of death in the long-term after heart transplantation. Multiple factors influence the initiation and progression of CAV. These include ischemia-reperfusion, dyslipidemia, insulin resistance, and hypertension due to the use of immunosuppressive agents, the direct effects of immunosuppressive agents on endothelial function, and viruses (CMV). Impaired endothelial function reflects abnormalities in the production or activity of several vasoactive substances. Disruption of the nitric oxide synthase (NOS) pathway leads to changes in vascular reactivity, structure, and interaction with circulating blood components. Since endothelium-derived nitric oxide (NO) suppresses vascular cell proliferation and vascular inflammation, a deficit in vascular NO facilitates development of CAV. The link between oxidative stress and CAV largely exists in the balance between free radical superoxide generation and NO production. This review focuses on identifying the oxidative stress factors affecting CAV.

Does Cyclosporine Down Regulate IL-17 in Cardiac Allograft Vasculopathy?

Background: Cardiac Allograft Vasculopathy (CAV) is characterized by vascular inflammation and intimal proliferation which results in luminal stenosis and myocardial infarction. During vascular inflammation elaboration of several cytokines and differential expression of growth factors have been noted. CAV remains the major threat to long-term graft survival. CD4 and CD8 T-cell subsets play a significant role in the development of transplant rejection. Chronic transplant rejection often leads to development of CAV. A new CD4 effector cell subset that produces IL-17 (Th17) has been shown to be up-regulated in the murine system in the setting of CAV. This study assesses the level of IL-17 in cardiac transplant patients with and without CAV as compared to nontransplanted controls. Methods: Levels of IL-17, IL-6, MCP-1 were measured by ELISA in plasma of four nontransplanted controls, nine cardiac allograft recipients with CAV (HT-GVD) and eight post transplant subjects without a diagnosis of CAV (HT-No GVD). All post transplant patients were immune suppressed with cyclosporine. HT-GVD patients were 1-15 years post transplant while HT-No GVD subjects were 1 - 10 years post transplant. Results: IL-17, MCP-1 and IL-6 were significantly down regulated in HT-GVD subjects compared to the HT-No GVD subjects (p 0.001) but not significant between controls and HT-No GVD (p = ns). Conclusions: A decrease in IL-17 in HT-GVD subjects as compared to HT-No GVD in the presence of cyclosporine treatment could be a consequence of down regulation of IL-6. It is likely that cyclosporine differentially regulates pro inflammatory molecules in the setting of graft vascular disease.

Expression of iNOSmRNA to prevent cardiac allograft vasculopathy after heart transplantation in rat

Objective Develop the model of post-transplant cardiac allograft vasculopathy (CAV) and prevent or treat CAV through Expression of iNOSmRNA.Methods Rat model of heterotopic heart transplantation was developed and three groups were divided as following: Comparison group, CsA group, iNSOmRNA group. Hearts were harvested at post-operative two weeks and four weeks and CAV was detected by immunohitochemical technique and in situ hybridization technique.Results iNOSmRNA group had no CAV develpment and synthetizing vast NO.Conclusion Expression of iNOSmRNA can prevent CAV development.

Effect of sirolimus on the expression of integrin αυβ3 mRNA in cardiac allograft in rats

Objective To investigate the effect of sirolimus ( SRL) on the expression of integrin αυβ3 mRNA in vascular smooth muscle cells of cardiac allografts in rats, and the possible mechanism of SRL in the prevention of cardiac allograft vasculopathy. Methods Heterotopic heart transplantation models were established Hearts

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% ),

Dysfunction of branded-chain amino acids catabolism in rat cardiac allograft

Objective Allograft vasculopathy ( AV) ,feature of chronic rejection,is a major serious long - term post - operation complication in organ transplantation. The accurate mechanisms for AV have not been definitively established,but extensive basic and clinical studies dem-

Effect of RDP1258 on survival of rat cardiac allograft

To investigate the effects of RDP1258 on survival of rat cardiac allograft.Methods RDP1258 was synthesized and the model of rat heart abdominal transplantation was established.Animals were divided into four groups.Group 1 received no immunosuppression.Group 2 received CsA alone.Group 3 received RDP1258 alone.Group 4 received RDP1258 and subtherapeutic CsA.In all cases RDP1258 was administrated intraperitoneally and CsA was gavaged.Light and electron microscopic examinations were taken.Transplanted hearts were monitored daily by direct palpation.Results The purity of synthesized RDP1258 was over 95% and the molecular weight was in accord with theoretical value.The histology and the ultrastructure changed little in grafts in group 3 and group 4.Survival of rat cardiac allograft was significantly prolonged in group 4.Conclusion RDP1258 can suppress acute rejection.Perioperative administration of RDP1258 in combination with CsA can significantly prolong survival of rat cardiac allograft.15 refs.

Allograft Inflammatory Factor-1 in Cardiac Ischemia Re-perfusion Injury: Release of Molecular Markers in an <i>in Vitro</i>Setting

Initial ischemia/reperfusion injury (IRI) may have an impact on recipient immune responses after transplantation. Allograft inflammatory factor-1 (AIF-1) has been implicated in the regulation of inflammation associated with organ rejection. We hypothesized that it is either passively released from injured tissues during organ procurement, or actively secreted by allograft infiltrating cells contributing to allograft dysfunction. We investigated the impact of IRI in an in vitro study of human heart tissue during the process of transplantation. The mRNA expression levels for both isoforms of the AIF-1, I2 and I3 were significantly increased after 30 minutes reperfusion (AIF-1 I2: p 0.01 vs. AIF-1 I3: p 0.005). Expression levels for IL-18 and the TLRs were increased after 30 minutes of reperfusion. Only IL-18 and TLR-2 were statistically significant (IL-18: p 0.0001 vs. TLR-2: p 0.01). The mRNA expression levels for AIF-1 I2 and IL-18 were decreased from the original levels of ischemia after 60 and 90 minutes reperfusion. The TLR-2 and -4 were presented with minimal levels of reduction after 60 minutes. However, mRNA expression levels for all were decreased to the original levels of ischemia after 90 minutes, except for AIF-1 I3, but the difference was not statistically significant. AIF-1 and IL-18 were specifically detected in myocytes and interstitial tissues by immunohistochemistry (IHC) stain after IRI. TLR-4 was non-specific, and TLR2 was minimally expressed. The study discusses the evidence supporting that the AIF-1 may have therapeutic potential for strategies in the control of innate immune responses early on, after transplantation.

Exosomes derived from microRNA-540-3p overexpressing mesenchymal stem cells promote immune tolerance via the CD74/nuclear factor-kappaB pathway in cardiac allograft

BACKGROUND Heart transplantation is a crucial intervention for severe heart failure,yet the challenge of organ rejection is significant.Bone marrow mesenchymal stem cells(BMSCs)and their exosomes have demonstrated potential in modulating T cells,dendtitic cells(DCs),and cytokines to achieve immunomodulatory effects.DCs,as key antigen-presenting cells,play a critical role in shaping immune responses by influencing T-cell activation and cytokine production.Through this modulation,BMSCs and their exosomes enhance graft tolerance and prolonging survival.AIM To explore the immunomodulatory effects of exosomes derived from BMSCs overexpressing microRNA-540-3p(miR-540-3p)on cardiac allograft tolerance,focusing on how these exosomes modulating DCs and T cells activity through the CD74/nuclear factor-kappaB(NF-κB)pathway.METHODS Rat models were used to assess the impact of miR-540-3p-enhanced exosomes on immune tolerance in cardiac allografts.MiR-540-3p expression was manipulated in BMSCs,and derived exosomes were collected and administered to the rat models post-heart transplantation.The study monitored expression levels of major histocompatibility complex II,CD80,CD86,and CD274 in DCs,and quantified CD4^(+)and CD8^(+)T cells,T regulatory cells,and cytokine profiles.RESULTS Exosomes from miR-540-3p-overexpressing BMSCs lead to reduced expression of immune activation markers CD74 and NF-κB p65 in DCs and T cells.Rats treated with these exosomes showed decreased inflammation and improved cardiac function,indicated by lower levels of pro-inflammatory cytokines(interleukin-1β,interferon-γ)and higher levels of anti-inflammatory cytokines(interleukin-10,transforming growth factorβ1).Additionally,miR-540-3p skewed the profiles of DCs and T cells towards immune tolerance,increasing the ratio of T regulatory cells and shifting cytokine secretion to favor graft acceptance.CONCLUSION Exosomes derived from BMSCs overexpressing miR-540-3p significantly enhance immune tolerance and prolong cardiac allograft survival by modulating the CD74/NF-κB pathway,which regulates activities of DCs and T cells.These findings highlight a promising therapeutic strategy to improve heart transplantation outcomes and potentially reduce the need for prolonged immunosuppression.

Diagnosis and management of coronary allograft vasculopathy in children and adolescents

Coronary allograft vasculopathy remains one of the leading causes of death beyond the first year post transplant. As a result of denervation following transplantation, patients lack ischaemic symptoms and presentation is often late when the graft is already compromised. Current diagnostic tools are rather invasive, or in case of angiography, significantly lack sensitivity. Therefore a non-invasive tool that could al ow early diagnosis would be invaluable.This paper review the disease form its different diagnosis techniques,including new and less invasive diagnostic tools to its pharmacological management and possible treatments.

Evaluation of the Management of Hyperlipidemia and Hypertension in an Outpatient Cardiac Transplant Clinic

Background: Allograft coronary artery disease (ACAD) is a common cause of morbidity and mortality post-orthotopic heart transplantation (OHT). ACAD progression may be reduced by modifying cardiovascular risk factors, such as hyperlipidemia and hypertension. We sought to evaluate the management of hyperlipidemia and hypertension among OHT recipients followed in an outpatient cardiac transplant clinic. Objective: The primary objective was to assess the proportion of OHT patients achieving both the recommended LDL target of <2.0 mmol/L and BP targets of <140/90 mmHg (or <130/80 mmHg for diabetics) in an outpatient cardiac transplant clinic. Methods: A cross-sectional retrospective analysis of the medical records of all adult OHT recipients actively followed in our outpatient cardiac transplant between January-March 2009. Results: Of the 193 patients included, both the low-density lipoprotein (LDL) cholesterol and blood pressure (BP) targets were achieved in 111 (57.5%) patients. The LDL target alone was achieved by 140 (72.5%) patients and the BP target alone by 153 (79.3%) patients. Statins were prescribed in 183 (94.8%) patients with a mean LDL of 1.81 mmol/L (±0.55). Angiotensin converting enzyme-inhibitors [ACE-I] (or angiotensin receptor blockers [ARB]) were prescribed in 154 (79.8%) patients, diltiazem in 101 (52.3%) patients, and both in 85 (44.0%) patients, with a mean BP of 124.2/77.8 mmHg (±13.6/8.2). Adverse reactions related to statins, ACE-inhibitors or diltiazem were uncommon and rarely resulted in drug discontinuation. Conclusions: Guideline recommended that LDL and BP targets are achievable in a significant proportion of OHT recipients. The high utilization rates of statins for dyslipidemia and ACE-I (or ARB) and diltiazem for BP were consistent with guideline recommendations for the prevention of ACAD. Despite concerns regarding the potential for pharmacokinetic drug interactions in OHT patients, the reported rates of any drug intolerance to these medications were low in our population.

雷公藤氯内酯醇对大鼠异位心脏移植免疫抑制作用的实验研究

本研究应用纯系大鼠（Ｌｏｕ→Ｆ３４４）心脏移植模型，比较分析了ＣｓＡ和不同剂量Ｔ４治疗组的移植心脏存活时间、病理损害计分以及移植受体大鼠脾单个核细胞ＩＬ－２生成活性和血清ｓＩＬ－２Ｒ水平，证实Ｔ４可明显延长移植心脏存活时间和减少移植排异反应程度。此研究结果表明Ｔ４具有较强的抗移植排异作用。

雷公藤内酯醇抗心脏移植排斥反应的实验研究

目的验证雷公藤内酯醇的抗移植排斥反应作用。方法应用小鼠同种异位心肌移植模型。结果和结论雷公藤内酯醇可明显延长移植心的存活期，其免疫抑制效果与用药剂量和给药时机有关，术后给药可明显延长移植物存活期。

合成组织相容性抗原衍生肽延长小鼠移植心肌存活时间的实验研究

目的 :探讨合成组织相容性抗原衍生 (HLA)肽延长小鼠移植心肌存活时间的供者特异性。 方法 :首先将NIH小鼠脾细胞 (5× 10 9/L ,0 2ml)注入Balb/c小鼠尾静脉 ,于注射前 7天、注射当日及之后连续 4天 ,每天给予HLA肽和亚治疗剂量的环胞素A(CsA) ,两周后将NIH和C5 7BL/ 6 (第三者 )新生鼠心肌分别移植于Balb/c小鼠左右耳后 ,不再给予HLA肽和CsA等免疫抑制剂。 结果 :移植与脾细胞同一供者小鼠 (NIH)心肌成活 ,在观察期内 (>2 0天 )未发生排斥反应 ;而移植的第三者 (C5 7BL/ 6 )心肌于移植后第 8天被排斥。 结论 :合成HLA肽加亚治疗剂量的CsA延长小鼠移植心肌存活时间具有供者特异性。

心脏移植的发展现状和新挑战

心脏移植是终末期心力衰竭患者的首选治疗。供者不足一直以来都是限制心脏移植数量增长的主要问题,随着新技术的不断更新和引入,供者池被不断扩大,比如使用年龄较大的供者、丙型肝炎病毒感染的供者、毒品过量致死的供者或心脏死亡器官捐献(DCD)供者的心脏等。与此同时,高龄、多器官功能不全、机械循环支持及人类白细胞抗原抗体致敏受者的比例近几年明显增加。供者数量的不足、受者状况的复杂化、免疫抑制治疗的个体化管理和远期移植物血管病的防治等都是心脏移植领域面临的挑战。本文通过概述现今全球在扩大供者库、提高受者质量、加强排斥反应的诊治和心脏移植物血管病变的预防等方面的新进展,以期有助于改善在等待或已经接受心脏移植的终末期心力衰竭患者的生存时间和生活质量。

大鼠心脏腹腔移植模型手术并发症的分析

目的:分析大鼠心脏腹腔移植模型建立中手术并发症的发生原因,以制订防治措施,提高移植成功率。方法:Wistar及SD大鼠分别作为供、受鼠,采用改进Ono术式腹腔移植术施行异位心脏移植。对预实验中并发症的发生情况进行统计,同时随机选取10只受鼠分别在麻醉后吸氧与不吸氧状态以及移植手术完成后进行血气分析, 经过技术处理和改良后,统计在正式实验中的并发症发生率,并进行对比分析。结果:预实验24只大鼠,并发症发生率为62．5％(9／24),正式实验40只,并发症发生率为12．5％(5／40);吸氧状态下氧分压[(128±2．83)mmHg] 较非吸氧状态氧分压[(74±2．42)mmHg]显著增高(P<0．05);移植手术创伤对大鼠的损伤导致各项生理指标方面均有显著变化,尤其是代谢性酸中毒较术前更为明显(P<0．05)。结论:预实验中发现并及时总结并发症的发生情况,对血气进行分析,通过改进手术方法和技巧、正确处理病理生理变化等措施,可显著提高正式实验的手术成功率及大鼠存活率。

左旋精氨酸抑制大鼠心脏移植术后移植物血管病的研究

目的 探讨左旋精氨酸 (L Arg)预防和治疗心脏移植术后移植物血管病的作用。 方法 建立大鼠异位心脏移植动物模型 ,观察给与L Arg、一氧化氮合酶 (NOS)抑制药物左旋精氨酸甲酯 (L NAME)后不同时间移植心脏冠状血管的改变。结果 L Arg组大鼠无移植物血管病 (CAV)的形成和一氧化氮 (NO)能大量合成 ,L NAME组大鼠有CAV形成。结论 NOS抑制药物L NAME加重移植后移植物血管病病变 ,L Arg可以预防和减轻移植后移植物血管病的病变 。

东莨菪碱对大鼠供心的保护作用

目的研究东莨菪碱在心脏移植中延长供体心脏低温保存时间的作用,探讨其可能的机制。方法将48只SD大鼠随机分为3组(n=16):对照组(C组,供心保存6h)、东莨菪碱组1(S1组,供心保存6h)和东莨菪碱组2(S2组,供心保存12h)。建立大鼠异位心脏移植模型。S1组和S2组的保存液中添加东莨菪碱(3mg/L),并在循环开放前静脉注射东莨菪碱(3μg/kg)。使用工作心脏模型检测心功能指标,取心肌组织检测NO含量,一氧化氮合酶(iNOS、cNOS)的活性和ICAM-1水平,以及iNOS、cNOS和ICAM-1mRNA表达。结果东莨菪碱能够改善移植后的心功能;下调再灌注后iNOS mRNA表达,降低iNOS活性,抑制cNOS的活性,总体上降低NO含量;通过下调ICAM-1mRNA水平,降低ICAM-1的表达。结论东莨菪碱能够减轻心肌缺血再灌注损伤,在心脏移植中延长供心低温缺血保存时间。其机制与调节心肌组织中NO水平、降低ICAM-1表达有关。

供者脾细胞对移植心脏免疫耐受的诱导

目的探讨供者脾细胞对同种异体心脏移植免疫耐受的诱导效果 ,为抗排斥反应治疗提供依据。方法分别采用供者脾细胞 (SPC)和环磷酰胺 (CP)预处理移植受者 ,然后行大鼠异位心脏移植术 ,根据实验分组对移植心脏存活情况进行观察。结果对照组、CP组和 SPC组移植心脏的存活时间分别为 7.2 1± 2 .5 6 d、9.78± 2 .5 5 d和 15 .14± 8.5 6 d,经统计学处理后证实 ,3组移植心脏的存活时间有显著性差异 (P<0 .0 5 )。结论供者脾细胞预处理移植受体 ,可以明显地延长大鼠同种异体心脏移植的存活时间。