Spironolactone Therapy in Pulmonary Arterial Hypertension (PAH)

肺动脉高压(PAH)是一种罕见的疾病，与生存不良有关。由1)遗传易感性和2)引发肺血管损伤的刺激引起的内皮功能障碍，即二次打击假说，似乎在PAH的发病和进展中发挥了核心作用。炎症似乎驱动了这种功能障碍的内皮表型，在遗传易感的特发性肺动脉高压(IPAH)患者和疾病相关的PAH患者中传播损伤和修复的周期。以肺血管炎症为靶点的治疗方法中断损伤和修复的循环，从而延迟或防止RV衰竭和死亡，尚未经过测试。 螺内酯是一种盐皮质激素受体(MR)和雄激素受体(AR)拮抗剂，已被证明具有改善内皮功能和减轻炎症的作用。目前对患有严重PAH和NYHA/WHO IV级症状的患者的治疗包括使用MR拮抗剂，在疗程后期，一旦出现临床右心衰竭，就使用MR拮抗剂进行利尿和利钠作用。目前，还没有从随机临床试验中检验MR拮抗剂治疗早期PAH的安全性和有效性的数据。 该方案的概念在2011年获得了NIH长凳到床边奖，正式的方案最初于2012年9月获得NHLBI IRB的批准。随后，在合作地点寻求并获得了IRB的批准，到2013年夏天，所有机构的各种修正案都得到了一致。 受试者接受1)标准的临床检查，包括6分钟步行距离和超声心动图；2)心肺运动试验；3)炎症和神经激素标记物的血浆图谱；4)外周血单核细胞(PBMC)的基因表达图谱；5)基于高分辨率MRI的肺血管和RV结构和功能的确定。通过定期监测高钾血症和肾功能不全以及因不良反应而停药的发生率，评估螺内酯在PAH中的安全性和耐受性。 到目前为止，在我们的自然历史方案(13-CC-0012)中登记的14名受试者中，有4人进入了这项研究(螺内酯随机干预试验)。四个受试者中有两个已经完成了研究。 支持招聘和增加入学人数的计划包括： 1)我们的首席调查员每周都会参加当地的一家肺部诊所，以便在定期预约期间与诊所工作人员和PAH患者进行沟通。 2)我们继续向当地的肺动脉高压支持团体展示我们的研究，因此，患者自我转介成为潜在研究对象的一个重要来源。我们计划继续与肺高压协会保持密切的工作关系，并计划今后向区域支助小组，包括目前正在马里兰州南部组织的一个新小组介绍情况。 3)研究护士继续定期访问当地的转介地点，以促进与诊所工作人员和PAH患者的沟通。 4)除了接触地区性学术中心外，我们还继续接触地区性临床实践。当地的肺科和心脏科医生都表示有兴趣转介病人。

Pulmonary arterial hypertension (PAH) is a rare disorder associated with poor survival. Endothelial dysfunction resulting from 1) genetic susceptibility, and 2) a triggering stimulus that initiates pulmonary vascular injury, the two-hit hypothesis, appears to play a central role both in the pathogenesis and progression of PAH. Inflammation appears to drive this dysfunctional endothelial phenotype, propagating cycles of injury and repair in genetically susceptible patients with idiopathic PAH (IPAH) and patients with disease-associated PAH. Therapy targeting pulmonary vascular inflammation to interrupt cycles of injury and repair and thereby delay or prevent RV failure and death has not been tested. Spironolactone, a mineralocorticoid receptor (MR) and androgen receptor (AR) antagonist, has been shown to improve endothelial function and reduce inflammation. Current management of patients with severe PAH and NYHA/WHO class IV symptoms includes use of MR antagonists for their diuretic and natriuretic effects, late in the course, once clinical right heart failure has developed. Currently, no well described data exists from randomized clinical trials examining the safety and efficacy of MR antagonist therapy in early stages of PAH. The concept for the protocol received an NIH Bench-to-Bedside Award in 2011 and a formal protocol was initially approved by the NHLBI IRB in September 2012. Subsequently IRB approval was sought and obtained at collaborating sites and various amendments were brought into alignment at all institutions by summer 2013. Subjects undergo 1) standard clinical examinations including 6-minute walk distance and echocardiography; 2) cardiopulmonary exercise testing; 3) plasma profiling of inflammatory and neurohormonal markers; 4) gene expression profiling of peripheral blood mononuclear cells (PBMCs); and 5) high-resolution MRI-based determination of pulmonary vascular and RV structure and function. Safety and tolerability of spironolactone in PAH is assessed with periodic monitoring for hyperkalemia and renal insufficiency as well as the incidence of drug discontinuation for untoward effects. To date of the 14 subjects enrolled in our Natural History protocol (13-CC-0012) four have been enrolled in this study (Spironolactone Randomized Interventional Trial). Two of the four subjects have completed the study. Plans for bolstering recruitment and increasing enrollment included: 1) Our lead investigator has been participating at a local pulmonary clinic weekly in order to facilitate communication with clinic staff and PAH patients during regularly scheduled appointments. 2) We continue to present our study to local pulmonary hypertension support groups and as a result, patient self-referrals have ben a significant source of potential subjects. We plan to continue to maintain a close working relationship with the Pulmonary Hypertension Association and are planning future presentations to regional support groups including a new group currently being organized in Southern Maryland. 3) Research nurses continue to conduct periodic visits to local referral sites in order to facilitate communication with clinic staff and PAH patients. 4) In addition to reaching out to regional academic centers we continue to reach out to regional clinical practices. Local pulmonary and cardiology practices, have expressed interest in referring patients.