脓毒症患者外周血淋巴细胞PPARγ表达和活性的变化

Changes of PPARγ protein expression and activity in peripheral blood lymphocytes of patients with sepsis

目的探讨不同病情程度和不同预后的脓毒症患者外周血淋巴细胞过氧化物酶体增殖物激活受体γ（peroxisome proliferator-activated receptor γ，PPARγ）的蛋白质表达量和活性的变化。方法根据2003年美国胸科医师学会／危重病医学会制定的脓毒症诊断标准，收集2007年12月至2008年3月复旦大学附属中山医院急诊科和外科ICU收治的48例脓毒症患者进行前瞻性研究，另选16例健康成年人作为对照。排除既往患有自身免疫性疾病、正在应用免疫抑制剂、AIDS和肿瘤患者。本研究获得复旦大学附属中山医院伦理委员会同意。根据患者的病情程度分为轻度脓毒症组和严重脓毒症组；根据患者28d是否存活，分为存活组和死亡组。利用Ficoll梯度离心法分离患者外周血淋巴细胞。分别采用蛋白质印迹（Western Blotting）和凝胶电泳迁移率（electrophoretic mobility shift assay，EMSA）方法测定外周血淋巴细胞PPAR7蛋白质表达量和活性变化。采用急性生理学与慢性健康评分Ⅱ（APACHEⅡ）系统对患者进行病情程度的评分。组间比较采用单因素方差分析。结果轻度脓毒症患者外周血淋巴细胞PPARγ蛋白质表达和活性（0．56±0．12，4．13±0．22）与正常对照组相比（0．39±0．07，2．42±0．17）明显增加、增强（P〈0．05）；严重脓毒症患者外周血淋巴细胞PPARγ蛋白质表达量和活性明显下降（0．30±0．07，1．63±0．12），均低于正常对照组和轻度脓毒症组（P〈0．05）。与脓毒症存活组患者相比（0．54±0．11，3．59±0．34），死亡组患者PPARγ蛋白质表达量和活性明显下降（0．21±0．08，1．94±0．25），差异具有统计学意义（P〈0．05）。结论外周血淋巴细胞PPARγ蛋白质表达量和活性对于预测脓毒症患者的病情程度和预后具有一定的参考价值。

Objective To investigate the changes of PPARγ protein expression and activity of peripheral blood lymphocytes in patients with sepsis and its association with severity and prognosis of sepsis. Method According to the guidelines to sepsis set by ACCP/SCCM consensus conference in 2003, 48 patients with sepsis admitted in Emergency and Surgical ICU from December 2007 to March 2008 were enrolled in this perspective study. Sixteen healthy individuals were selected as controls. Patients with metastatic tumors, autoimmune disease, AIDS or under innnunosuppressive therapy were excluded. This study was approved by the ethical committee of Zhongshan Hospital, Fudan University. All patients were divided into mild and severe sepsis groups. Patients were also divided into snrvivor and non-survivor groups as per 28-day mortality. Peripheral blood lymphocytes were isolated by using Ficoll density gradient centrifugation. PPARγ protein expression was determined by using Western Blotting. The activity of PPARγ was analyzed by using EMSA. Differences among groups were analyzed by using oneway ANOVA. Results The protein expression and activity of PPART were significantly increased in mild sepsis patients （0,56 ± 0.12 and 4.13 ± 0.22, respectively） compared with both healthy controls （0.39 ± 0.07 and 2.42 ± 0.17, respectively） and severe sepsis patients （0.30 ± 0.07 and 1.63 ± 0.12, respectively） （ P 〈 0.05）. However, the protein expression and activity of PPARγ were obviously decreased in severe sepsis patients compared with healthy individuals and mild sepsis patients （ P 〈 0.05）. Survivors from sepsis had significantly higher protein expression and activity （0.54 ± 0.11 and 3.59 ± 0.34, respectively） than non-survivors （0.21 ± 0.08 and 1.94 ± 0.25, respectively） （ P 〈 0.05）. Conclusions These data suggest that the protein expression and activity of PPARγ in peripheral blood lymphocytes might be valuable biomarkers in assessing the severity and outcome of patients with sepsis.