高詩奇 鄧代華 楊靜
摘要:成纖維細胞生長因子(FGF21)是一種參與糖脂代謝和胰島素分泌調控的內分泌因子,主要在肝臟、脂肪、胰腺和肌肉組織中表達和分泌。近年來研究表明,FGF21具有心血管保護作用,可抑制動脈粥樣硬化的發生、發展。FGF21不僅可以作為預測動脈粥樣硬化的生物標志物,還可能作為治療代謝性疾病及動脈粥樣硬化性心血管疾病的潛在靶點。本文就FGF21及其抗動脈粥樣硬化作用、生物標記物作用作一綜述,以期為臨床治療提供參考。
關鍵詞:成纖維細胞生長因子21;動脈粥樣硬化;生物標志物
中圖分類號:R543.5? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 文獻標識碼:A? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? DOI:10.3969/j.issn.1006-1959.2020.19.009
文章編號:1006-1959(2020)19-0028-03
Abstract:Fibroblast growth factor (FGF21) is an endocrine factor involved in the regulation of glucose and lipid metabolism and insulin secretion. It is mainly expressed and secreted in liver, fat, pancreas and muscle tissues. Recent studies have shown that FGF21 has cardiovascular protective effects and can inhibit the occurrence and development of atherosclerosis. FGF21 can be used not only as a biomarker for predicting atherosclerosis, but also as a potential target for the treatment of metabolic diseases and atherosclerotic cardiovascular diseases. This article reviews FGF21 and its anti-atherosclerosis and biomarker effects in order to provide reference for clinical treatment.
Key words:Fibroblast growth factor 21;Atherosclerosis;Biomarker
動脈粥樣硬化(atherosclerosis,AS)是心血管疾病發生發展的重要病理生理基礎,也是高血壓、糖尿病、高尿酸血癥等代謝性疾病導致的靶器官損害之一,其特點是在炎癥、氧化應激等的作用下,動脈內膜過度纖維化、脂肪斑塊形成、平滑肌細胞增殖[1-3]。在發生動脈粥樣硬化之前,利用生物標志物識別高風險人群對于預測和預防動脈粥樣硬化、降低心血管疾病發生率和改善預后具有重要意義。成纖維細胞生長因子(fibroblast growth factor 21,FGF21)是成纖維細胞生長因子超家族(fibroblast growth factors,FGFs)中的一員,是近些年被廣泛研究的代謝調節因子,具有改善胰島素抵抗、改善脂代謝、抗氧化應激、抗炎等作用[1-3]。研究表明[4,5],在亞臨床及臨床動脈粥樣硬化患者血清中FGF21水平升高。另有研究表明[6-8],給予外源性FGF21對動脈粥樣硬化有潛在治療作用。本文主要從FGF21概述及其抗動脈粥樣硬化作用、生物標記物作用進行綜述。
1 FGF21概述
FGF21基因最早于2000年由Nishimura T等[9]從小鼠胚胎組織中克隆得到。FGF21屬于FGF19亞家族,是一種多功能蛋白,主要由肝臟、脂肪組織、胰腺組織和肌肉組織分泌[9],在體內通過一種單通道跨膜蛋白βKlotho作為專性輔因子激活FGF受體(fibroblast growth factor receptor,FGFR)形成FGF21-βKlotho-FGFR復合體而發揮生物學效應。FGF21的表達主要受肝臟中過氧化物酶體增殖物激活受體α(peroxisome proliferators activated receptor α,PPARα)的調控和脂肪細胞中過氧化物酶體增殖物激活受體γ(peroxisome proliferators activated receptor γ,PPARγ)的調控。研究發現[10,11],FGF21有改善胰島素的敏感性、降低血糖、改善脂代謝等生理學作用。
2 FGF21的抗動脈粥樣硬化作用
2.1對血管內皮細胞的保護作用? ox-LDL誘導的血管內皮細胞凋亡是動脈粥樣硬化進展的重要步驟。Chen J等[12]研究發現,FGF21可以降低oxLDL誘導的線粒體動力相關蛋白(dynamin-related protein 1,Drp1)表達,抑制線粒體分裂,保護線粒體和細胞形態功能,減少ox-LDL誘導的血管內皮細胞(vascular endothelial cells,VECs)凋亡,進一步抑制動脈粥樣硬化。Yan X等[13]研究表明,FGF21可以通過抑制Fas的表達來保護人臍靜脈內皮細胞(human umbilical vein endothelial cells,HUVECs)的凋亡,在apoE-/-小鼠中可通過改善Fas介導的細胞凋亡來減輕動脈粥樣硬化。另研究表明[14],FGF21可通過激活CaMKK2-AMPKα信號通路改善糖尿病誘導的內皮功能障礙小鼠的氧化應激,并且FGF21可與FGF受體結合對主動脈內皮細胞直接發揮作用,以減輕高糖對內皮細胞功能的損害。
2.2改善脂代謝? 動脈內膜中過多脂質的積累是動脈粥樣硬化發生和發展的重要原因之一[2],降低脂質譜,尤其是膽固醇,可以抑制動脈粥樣硬化的發生發展。Dong J等[15]體內研究結果顯示,對肥胖或超重2型糖尿病患者單次靜脈注射長效FGF21類似物PF-05231023,可顯著降低甘油三酯、總膽固醇和低密度脂蛋白水平,并使高密度脂蛋白水平升高。Talukdar S等[16]對肥胖獼猴連續靜脈注射長效FGF21類似物PF-05231023,可顯著降低體重體重,改善血漿脂蛋白譜并使脂聯素水平升高。脂聯素是體內由脂肪細胞分泌的一種重要的生物活性因子,可通過減輕氧化應激,減少血管細胞粘附分子1(VCAM-1)等粘附分子來抑制巨噬細胞浸潤,從而發揮抗動脈粥樣硬化作用。
膽固醇調節元件結合蛋白2(sterol regulatory elementbinding protein-2,SREBP2)是調節膽固醇生物合成的主要轉錄因子。Lin Z等[17]研究顯示,apoE-/-小鼠注射FGF21后可通過激活FGFR2-βklotho受體復合物進而抑制SREBP-2表達,并降低apoE-/-小鼠肝臟中的總膽固醇。Li Q等[18]研究表明,蘇木乙酸乙酯提取物(ethyl acetate extract of sappanwood,SEAE)可通過FGF21/SREBP-2信號通路降低動脈粥樣硬化大鼠的總膽固醇、甘油三酯和低密度脂蛋白水平。自噬是一種高度保守的細胞應激反應,它通過減少泡沫細胞中脂滴降解來調節動脈粥樣硬化。研究表明[19],FGF21增加了ApoE-/-小鼠斑塊激活的蛋白激酶C受體1(activated kinase C receptor 1,RACK1)和自噬相關蛋白的表達,促進膽固醇外排,從而減少泡沫細胞中膽固醇的積累,進而改善高脂飲食ApoE-/-小鼠的動脈粥樣硬化。總之,FGF21可通過改善脂質譜、調節脂代謝而發揮抗動脈粥樣硬化作用。
2.3改善氧化應激及抗炎作用? 炎癥反應及氧化應激是動脈粥樣硬化發生發展的重要環節。研究表明[20,21],FGF21是一種新型的氧化應激調節因子。核轉錄因子E2相關因子(nuclear transcription factor E2-related factor,Nrf2)是氧化應激的敏感調節因子,也與動脈粥樣硬化進展相關。Jia H等[22]研究中發現,上調動脈粥樣硬化大鼠FGF21可增加Nrf2-ARE信號轉導相關蛋白的表達,提高抗氧化指標水平,降低內皮功能障礙水平,降低炎癥指標,而下調FGF21可以逆轉這些作用。表明FGF21可通過Nrf2-ARE信號通路降低動脈粥樣硬化大鼠的炎癥和氧化應激。Liu J等[23]給予暴露于缺氧條件下的大鼠服用FGF21,發現FGF21減輕了缺氧引起的平均肺動脈壓、右心室肥厚和肺動脈平滑肌細胞(pulmonary artery smooth muscle cells,PASMCs)的過度增殖。南瑛等[24]研究表明,FGF21可以通過SIRT1/PGC1α通路改善棕櫚酸酯誘導的線粒體活性氧(reactive oxygen species,ROS)產生,改善細胞線粒體損傷及線粒體功能障礙,同時可減少腫瘤壞死因子α(tumor necrosis factor,TNF-α)和白介素6(interleukin-6,IL-6)等炎癥細胞因子的釋放,從而減輕炎癥反應。總之,FGF21可以通過改善氧化應激、抗炎來實現抗動脈粥樣硬化的作用。
3 FGF21的生物標記物作用
越來越多證據表明,FGF21水平在代謝疾病及動脈硬化性心血管疾病中多有升高,被認為是疾病早期診斷的潛在生物標志物。Wang X等[25]對68例冠心病患者進行了模擬組織-血管超聲檢查,并測定其循環FGF21的濃度,發現血清FGF21水平與斑塊負荷呈顯著正相關。另一項大規模研究表明[26],在5年的隨訪中,高水平的FGF21與2型糖尿病患者發生心血管事件的風險增加有關。Wu L等[27]研究表明,非酒精性脂肪肝合并亞臨床動脈粥樣硬化的患者中FGF21水平升高,基線FGF21水平是動脈粥樣硬化性心血管疾病的獨立預測因子。Basurto L等[28]的研究對無心血管疾病史的絕經后女性單核細胞趨化蛋白-1(monocyte chemotactic protein 1,MCP-1)和FGF21的血清濃度進行測定,并測定頸動脈內膜中層厚度(cIMT),結果發現MCP-1和FGF21水平與亞臨床動脈粥樣硬化嚴重程度(即cIMT)相關。另有研究發現[29],血清FGF21在合并有亞臨床動脈粥樣硬化的2型糖尿病患者中升高,logistic回歸發現FGF21是亞臨床動脈粥樣硬化的獨立預測因子。以上研究表明FGF21水平升高可以預測動脈粥樣硬化及動脈粥樣硬化相關疾病的發生、發展,可以作為早期發現亞臨床動脈粥樣硬化的潛在生物標志物。
4總結
FGF21通過其抗氧化、抗炎、降脂和誘導脂聯素表達等作用,直接和間接地抑制了動脈粥樣硬化的發生發展。但目前這些研究多在實驗模型中進行,由于人與嚙齒類動物動脈粥樣硬化易感性存在差異,因此FGF21對人動脈粥樣硬化的治療作用仍需要更多研究。此外,還需要進一步的前瞻性研究來發現FGF21是否可以作為一種預測生物標志物來識別動脈粥樣硬化相關疾病中未來發生動脈粥樣硬化的高風險個體,或者FGF21治療是否可以降低這些疾病中動脈粥樣硬化發生的風險,是否可以起到真正的預防作用。
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收稿日期:2020-07-04;修回日期:2020-07-14
編輯/杜帆