机械瓣膜置换术后华法林抗凝治疗个体化差异的药物基因组学研究

Patients after heart mechanical valve replacement need to use warfarin commonly. But because warfarin's safety range is narrow and individual dose is different, so patients easy to occur complications, such as thrombopoiesis and haemorrhage. How to use warfarin reasonably is the key of preventing complication and it has become a hot topic in area of cardiovascular surgery. Researches revealed, genetic factor is the most mainly reason that lead to different dosage in patients. Recently, warfarin algorithm model which base on SNPs that associated with etabolism of warfarin in America. We supposed, because of different ethnic group, it is necessary to build warfarin individual therapy algorithm model that base on Chinese patients' hereditary feature. At early stage, We have build sample base of patients, and set up genotyping method associate with etabolism of warfarin. Our target people are patients after heart mechanical valve replacement in Han people of northern China. Our study will use HPLC to exam speed rate of warfarin's estabolism, and use genome-wide association study (GWAS) to scan SNPs that associate with sensibility of warfarin. What's more, we will use many sites conjoint-analysis method to study correlation between SNPs that we found and warfarin dose, and find some characteristic SNPs in Han people of northern China. Finally, we try to conbine inherent factors with non-inherent factors, use method of complicated disease statistics to establish "warfarin pharmacogenetic algorithm model". It can contribute to reduce anticoagulation complications, decrease mortality, improve life quality and provide a new method for individual therapy.

华法林是机械瓣膜置换术后患者最常用口服抗凝药，其安全范围窄、个体差异大，易出现出血或血栓形成等并发症。华法林合理用药是预防并发症的关键，受到心外科领域高度关注。研究显示，遗传因素是造成华法林个体差异的主要原因，最近美国已见基于华法林代谢相关SNP的个体化治疗剂量模型。我们提出："由于人种差异，需依据我国患者遗传特点建立个体化治疗剂量模型"的假设。前期已建立换瓣术患者样本资源库，初步建立华法林代谢相关基因分型方法。本研究拟以北方地区汉族换瓣术患者为研究对象，高压液相色谱多点测定华法林代谢速率，全基因组芯片扫描与华法林敏感性相关SNP位点及单倍体，联合分析法探讨SNP与该药代谢速度及剂量的相关性，发现和确定北方汉族人群特有的新基因及位点，同时结合环境因素运用复杂疾病统计学分析法建立适用于我国汉族人群的"个体化药物剂量预测模型"，实现个体化治疗减少并发症。

华法林是临床上广泛使用的抗凝剂，但其治疗窗窄，个体剂量差异大，如何对患者进行精准用药，实现个体化治疗是目前的研究热点。本研究建立了中国北方汉族人群机械瓣膜置换术后患者数据库和DNA样本库，收录600例患者数据。课题组对北方地区机械瓣膜置换术后患者华法林稳定剂量的人口学因素、合并用药等因素研究发现年龄、性别、体表面积、长期服用华法林抗凝增效药与华法林稳定剂量间有显著的相关性，多因素线性回归方程得到人口学因素和合并用药因素可解释14.1%的华法林剂量个体差异。我们筛选了与华法林药代动力学与药效动力学基因30种共96个单核苷酸多态位点，定制了相关基因分型芯片，对患者基因型进行了检测，通过单因素及多因素回归分析发现VKORC1（rs9923231）、CYP2C9（rs1957910）、CYP1A2（rs2069514）、CYP3A4（rs28371759）、APOE（rs7412）、EPHX1（rs2260863）基因多态性与华法林稳定剂量之间存在相关性。基因多态性是影响北方地区机械瓣膜置换术后患者华法林稳定剂量的遗传因素，共同解释32.4%的华法林剂量差异。提示其基因多态性是影响北方地区机械瓣膜置换术后患者华法林剂量差异的遗传因素。综合遗传和非遗传因素建立北方地区机械瓣膜置换术后患者华法林稳定剂量预测模型，验证模型的准确性并和IWPC模型进行比较。该模型可解释45.1%的华法林稳定剂量个体差异。Pearson相关分析证实该模型预测剂量与实际剂量之间有较好的相关性，该模型的预测剂量与实际剂量间的相关性优于IWPC模型。在中剂量组（2-4mg/天），本研究构建的北方地区剂量模型预测准确性优于IWPC算法模型，在低剂量组（<2mg/天）和高剂量组（>4mg/天），两个模型预测准确性无明显差别。该模型适合我国北方汉族人群，将此模型应用于临床，有助于提高华法林用药的安全性和准确性，实现个体化抗凝治疗。