简介：Calcineurin(CaN)为蛋白磷酸酶2B家族成员,是目前唯一已知的细胞内Ca2+/钙调素依赖性蛋白磷酸酶.

简介：目的:研究大鼠心肌肥厚时,钙依赖的蛋白激酶和蛋白磷酸酶在心肌细胞膜、细胞浆和细胞核的分布规律,以探讨核钙信号与核反应在心肌肥厚发生过程中的病理生理意义.方法:制备腹主动脉缩窄大鼠心肌肥厚模型、差速离心和密度梯度离心提纯心肌细胞核,同位素32P掺入法测激酶活性,无机磷生成显色法测定蛋白磷酸酶活性.结果:腹主动脉缩窄术后4周大鼠心肌显著肥厚,伴有明显的血液动力学异常.与正常对照组相比较,腹主动脉缩窄心肌肥厚组心肌细胞核钙调素蛋白激酶(CaMK)活性增加1.011倍(p＜0.001),膜升高40.16%(p＜0.001),胞浆不变(p＞0.05);心肌细胞核钙调神经磷酸酶(Calcineurin)活性增加43.57%(p＜0.05),膜和胞浆增加无显著性(p＞0.05).正常组和腹主动脉缩窄心肌肥厚组心肌细胞CaMK和Calcineurin活性分布为核＞膜＞胞浆(p＜0.01).结论:腹主动脉缩窄心肌肥厚时核内钙依赖的CaMK和Calcineurin活性增加,提示压力超负荷时细胞核内钙调节的蛋白磷酸化和去磷酸化水平增高,可能在介导心肌肥厚的发生中起重要作用.

简介：心肌肥大是心肌对各种内外刺激的适应性反应,包括高血压、心肌梗死、心律失常、瓣膜病、内分泌疾病等等.起初的心肌肥大是有益的,但持久的肥大可导致扩张性心肌病、心衰及猝死.有几种药物已显示可维持心衰病人的心功能及延长生命,但5年死亡率仍近50%.过去十年中已有不少文章描述了不同的信号转导通路,它们能诱导培养的心肌细胞和转基因鼠的心肌肥大.最近有报道Ca2+/钙调蛋白(CaM)依赖性蛋白磷酸酶calcineurin能在体内外转导肥大信号,而抑制calcineurin活性可阻断与肥大有关的细胞和分子事件[1],并且最终建立了通过激活calcineurin而刺激肥大的转导模型.因calcineurin通道可被免疫抑制剂所抑制,因此倍受关注.

简介：AbstractBackground:The calcineurin inhibitor (CNI)-based immune maintenance regimen that is commonly used after renal transplantation has greatly improved early graft survival after transplantation; however, the long-term prognosis of grafts has not been significantly improved. The nephrotoxicity of CNI drugs is one of the main risk factors for the poor long-term prognosis of grafts. Sirolimus (SRL) has been employed as an immunosuppressant in clinical practice for over 20 years and has been found to have no nephrotoxic effects on grafts. Presently, the regimen and timing of SRL application after renal transplantation vary, and clinical data are scarce. Multicenter prospective randomized controlled studies are particularly rare. This study aims to investigate the effects of early conversion to a low-dose CNI combined with SRL on the long-term prognosis of renal transplantation.Methods:Patients who receive four weeks of a standard regimen with CNI + mycophenolic acid (MPA) + glucocorticoid after renal transplantation in multiple transplant centers across China will be included in this study. At week 5, after the operation, patients in the experimental group will receive an additional administration of SRL, a reduction in the CNI drug doses, withdrawal of MPA medication, and maintenance of glucocorticoids. In addition, patients in the control group will receive the maintained standard of care. The patients’ vital signs, routine blood tests, routine urine tests, blood biochemistry, serum creatinine, BK virus (BKV)/cytomegalovirus (CMV), and trough concentrations of CNI drugs and SRL at the baseline and weeks 12, 24, 36, 48, 72, and 104 after conversion will be recorded. Patient survival, graft survival, and estimated glomerular filtration rate will be calculated, and concomitant medications and adverse events will also be recorded.Conclusion:The study data will be utilized to evaluate the efficacy and safety of early conversion to low-dose CNIs combined with SRL in renal transplant patients.Trial registration:Chinese Clinical Trial Registry, ChiCTR1800017277.