MMP9 as a response identification biomarker for doxycycline in Kawasaki disease

摘要 川崎（KD）是发达国家儿童获得性心脏病的主要原因。它 表现为一种急性自限性疾病，伴有发热和皮肤及粘膜炎症。在 KD，由迄今未知的外在因素触发的免疫系统诱导多系统血管炎，包括 冠状动脉即使按照目前的治疗指南，30%的KD儿童也会发生冠状动脉粥样硬化。 动脉扩张（CAD）。CAD患者可能面临永久性和潜在的破坏性并发症， 如冠状动脉血管病变、心肌梗死甚至死亡。目前没有可用的治疗方法或 KD患儿CAD的预防在KD急性期，巨噬细胞和淋巴细胞活化， 冠状动脉壁诱导基质金属蛋白酶9（MMP-9）， 降解导致CAD和动脉瘤。强力霉素（一种常见的抗生素和已知的MMP-9抑制剂） 降低MMP-9介导的冠状动脉弹性蛋白的破坏，改善冠状动脉预后。 KD动物模型强力霉素给药也被证明可以降低主动脉中MMP-9的活性。 成人腹主动脉瘤壁。我们的初步和公布的数据表明，亲- MMP-9是检测KD患儿急性期炎症反应的敏感生物标志物， 多西环素可预防KD患儿CAD的进展。根据这些数据，我们将 检验以下两个假设：1）KD急性期儿童给予强力霉素将 降低MMP-9的循环水平; 2）在KD急性期使用强力霉素是安全的 并有效预防儿童CAD和动脉瘤形成的进展。 具体目标1：表征循环MMP-9原和MMP-9水平响应于3-羟色胺的变化。 在KD急性期儿童口服强力霉素一周，通过定量测定前 3周前和3周后儿童血清样本中的MMP-9和MMP-9水平（通过ELISA测量） 多西环素治疗过程，并比较急性KD儿童和非KD儿童的变化。 强力霉素治疗。具体目标2：评估冠状动脉直径对3- 通过评估KD急性期儿童口服多西环素的大小， 在KD急性期的4个时间点使用已建立的超声心动图标准测量冠状动脉 并与未用强力霉素治疗的急性川崎病患儿作对照。根据这个结果， 初步研究，我们将开展一项前瞻性、多中心、盲法对照临床试验，以评估 多西环素治疗预防冠心病和动脉瘤。如果强力霉素被证明是有益的，我们将 建议改变目前接受的KD儿童治疗方案，包括多西环素， 预防冠状动脉瘤和潜在的致命并发症。

ABSTRACT Kawasaki disease (KD) is the leading cause of acquired heart disease in children of the developed world. It presents as an acute self-limiting illness with fever and inflammation of the skin and mucous membranes. In KD, the immune system triggered by a so far unknown extrinsic factor induces multisystem vasculitis including the coronary arteries. Even following current therapeutic guidelines, 30% of children with KD will have coronary artery dilation (CAD). Patients with CAD may face permanent and potentially devastating complications, such as coronary vasculopathy, myocardial infarction and even death. Currently there is no available treatment or prevention of CAD in children with KD. In the acute phase of KD, activated macrophages and lymphocytes in the wall of the coronary arteries induce matrix metalloproteinase 9 (MMP-9) that is responsible for elastin degradation causing CAD and aneurysm. Doxycycline (a common antibiotic and a known inhibitor of MMP-9) was shown to decrease MMP-9-mediated coronary elastin breakdown and improve coronary outcome in animal models of KD. Doxycycline administration was also demonstrated to reduce MMP-9 activity in the aortic wall of adults with abdominal aortic aneurysm. Our preliminary and published data demonstrates that pro- MMP-9 is a sensitive biomarker to detect inflammation in children during the acute phase of KD when CAD occurs, and doxycycline may prevent the progression of CAD in children with KD. Based on these data, we will test the following two hypotheses: 1) doxycycline administration in children during the acute phase of KD will decrease the circulating level of MMP-9; and 2) doxycycline treatment during the acute phase of KD is safe and effective to prevent the progression of CAD and aneurysm formation in children. Specific aim 1: To characterize the change in circulating pro-MMP-9 and MMP-9 levels in response to a 3- week oral administration of doxycycline in children during the acute phase of KD, by the quantification of pro- MMP-9 and MMP-9 levels (measured by ELISA) in serum samples of children before and after a 3-week course of doxycycline treatment, and comparing the changes to controls of children with acute KD and no doxycycline treatment. Specific aim 2: To assess the change in coronary artery diameter in response to a 3- week oral administration of doxycycline in children during the acute phase of KD, by assessing the size of coronary arteries using established echocardiographic standards during 4 time-points in the acute phase of KD and comparing to controls of children with acute KD and no doxycycline treatment. Based on the results of this pilot study, we will develop a prospective, multi-center, blinded controlled clinical trial to assess the efficacy of doxycycline treatment in the prevention of CAD and aneurysm. If doxycycline proves to be beneficial, we will propose a change of the currently accepted treatment protocol of children with KD to include doxycycline for the prevention of coronary artery aneurysms and potentially fatal complications.