心臟病發作後的組織損傷往往會最終導致心力衰竭,而加州大學Davis分校(UC Davis)的一項新研究,通過抑制一個促炎症的酶阻斷了上述組織損傷,此外研究人員還確定了其中的分子機制。文章發表在美國國家科學院院刊PNAS雜誌上。
可溶性環氧化物水解酶sEH,是組織修復相關免疫應答中的關鍵成員,不過在心臟病發作後,這種酶往往會產生事與願違的影響。Chiamvimonvat解釋道,sEH使促炎症的脂類介質增多,從而引起高水平的炎症,另外這種酶還會引發疤痕組織或者纖維化,最終使心臟功能衰退。研究人員在Nipavan Chiamvimonvat教授的帶領下,對sEH抑制劑進行了測試。
「在臨床上常常出現這樣的現象,心臟病發作的患者一開始治療效果良好,」致力於研究心臟病生物學機制的Chiamvimonvat說。「但隨著時間推移,一些患者的心臟功能持續惡化,導致心力衰竭。」
心力衰竭會逐漸限制全身的氧供給,損害患者的運動能力、呼吸能力和生活質量。據美國疾控中心統計,這種疾病影響了五百七十萬美國人,造成了大量的經濟損失。約有半數的心力衰竭患者在確診後的五年內死亡。.
此前,研究人員曾發現sEH抑制劑能夠緩解心肌細胞增大和相應心律失常。現在他們又進行了一系列實驗,測試這一化合物治療心肌纖維化的能力。心臟病發作和慢性心臟疾病都有可能引起心肌纖維化,因此研究人員對心臟病發作和高血壓小鼠模型分別進行了研究。高血壓會給心臟帶來慢性的壓力負荷。
研究人員將上述小鼠模型各分為兩組,一組通過飲用水攝入sEH抑制劑,一組作為對照。然後他們通過超聲心動圖echocardiography來評價這些小鼠的心臟功能。研究顯示,sEH抑制劑顯著減少了小鼠體內的有害心肌重塑,使其總體心臟功能得到改善。有害心臟重塑包括心肌細胞肥大、纖維化和電重構。
「心臟纖維化是心臟病學中最棘手的問題之一,而我們為此提供了新的治療靶標,」文章的共同作者,助理教授Javier Lopez說。研究人員指出,接受抑制劑治療的小鼠,體內的炎症因子也顯著減少。
下一步,研究團隊希望在更大型的模式動物中測試sEH抑制劑的治療效果,然後進入人類臨床試驗。該研究的作者中還包括山東大學的趙翠芬(音譯Cuifen Zhao)。(生物谷Bioon.com)
Unique mechanistic insights into the beneficial effects of soluble epoxide hydrolase inhibitors in the prevention of cardiac fibrosis
Sirish P, Li N, Liu JY, Lee KS, Hwang SH, Qiu H, Zhao C, Ma SM, López JE, Hammock BD, Chiamvimonvat N.
Tissue fibrosis represents one of the largest groups of diseases for which there are very few effective therapies. In the heart, myocardial infarction (MI) resulting in the loss of cardiac myocytes can culminate in adverse cardiac remodeling leading to eventual heart failure. Adverse cardiac remodeling includes myocyte hypertrophy, fibrosis, and electrical remodeling. We have previously demonstrated the beneficial effects of several potent soluble epoxide hydrolase inhibitors (sEHIs) in different models of cardiac hypertrophy and failure. Here, we directly determine the molecular mechanisms underlying the beneficial effects of sEHIs in cardiac remodeling post-MI. Treatment with a potent sEHI, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidine-4-yl)urea (TPPU), which was started 1 wk post-MI in a murine model, results in a significant improvement in cardiac function. Importantly, treatment with TPPU results in a decrease in cardiac fibrosis as quantified using histological and immunostaining techniques. Moreover, single-cell-based assays demonstrate that treatment with TPPU results in a significant decrease not only in the percentages but also the proliferative capacity of different populations of cardiac fibroblasts as well as a reduction in the migration of fibroblasts into the heart from the bone marrow. Our study provides evidence for a possible unique therapeutic strategy to reduce cardiac fibrosis and improve cardiac function post-MI .