Ezetimibe

Ezetimibe is a selective cholesterol absorption inhibitor with IC₅₀ values of 50µM for lung cancer cell (A549), human embryonic kidney cells (HEK293) and 30µM for melanoma cell (A375) for 48h^[1]. Ezetimibe primarily acts by blocking the Niemann-Pick C1-Like 1 (NPC1L1) protein in the small intestine, reducing the intestinal absorption of dietary and biliary cholesterol, which leads to a decrease in low-density lipoprotein cholesterol (LDL-C) levels ^[2].

In vitro, Hepa1c1c7 (mouse hepatoma) and MEF (mouse embryonic fibroblast) cells were treated with Ezetimibe (50μM) for 18h. Ezetimibe enhanced transactivation of Nrf2, as revealed by a luciferase reporter assay. Ezetimibe also upregulated Nrf2 target genes, including GSTA1, heme oxygenase-1 (HO-1) and Nqo-1 in a p62-dependent manner. Saturated fatty acids such as PA lead to ROS-mediated apoptotic cell death. Hepa1c1c7 cells pretreated with Ezetimibe (50μM) for 1h and incubated in the presence of PA for 18h have reduced cell death, apoptotic cell death, and TUNEL positive cells. Ezetimibe prevented against PA-induced apoptotic cell death through p62 phosphorylation-mediated Nrf2 activation^[3]. The sodium taurocholate co-transporting polypeptide (NTCP), a hepatic bile acid transporter, facilitates α-amanitin entry into hepatocytes. Human normal hepatocytes cells (L-02) and human hepatocellular carcinoma cells (HepG2) were cultured with Ezetimibe (1–6μM) for 48h. Ezetimibe significantly increased the viability of α-amanitin-stimulated hepatocytes and reduced inflammatory factor levels by inhibiting NTCP. Ezetimibe treatment also significantly reduced oxidative stress, with increased serum superoxide dismutase (SOD) and catalase (CAT) levels and decreased malondialdehyde (MDA) levels, suggesting alleviation of α-amanitin-induced oxidative stress^[4].

In vivo, albino mice received Ezetimibe at a dose of 2.5mg/kg p.o or a dispersion of the physical mixture of atorvastatin (5mg/kg; p.o) and Ezetimibe (2.5mg/kg; p.o) on daily basis for 2 weeks. Co-administration of both drugs in the form of physical mixture resulted in additional reduction in cholesterol concentration compared with each drug individually and this can be attributed to the synergetic pharmacological effect of atorvastatin and Ezetimibe. This synergistic pharmacological effect was reported as atorvastatin is able to inhibit HMG-CoA reductase (the rate-limiting enzyme in cholesterol biosynthesis in liver) and Ezetimibe that inhibits cholesterol absorption from small intestine^[5]. The Wistar rats were randomly assigned to an Ezetimibe or control group at 6 weeks of age. The control group received an high fat diet (60 Kcal%), whereas the Ezetimibe group received an high fat diet (60 Kcal%) containing 160mg/kg Ezetimibe for 14 weeks. The use of Ezetimibe reduced the sizes of adipocytes in visceral fat. Ezetimibe also reduced the accumulation of pro-inflammatory cytokines and induced the production of anti-inflammatory cytokines within adipocytes, leading to increased fatty acid oxidation; reduced levels of free fatty acids and improved insulin resistance^[6]. Male obese and diabetic OLETF rats were administered either PBS or Ezetimibe (10mg/kg per day) via stomach gavage for 20 weeks. Ezetimibe significantly decreased liver weight and lipid parameters including triglycerides (TG), free fatty acids (FFA), and total cholesterol (TC) in liver tissue. Autophagy-related mRNA expression including ATG5, ATG6, and ATG7 and the protein level of microtubule-associated protein light chain 3 (LC3) were significantly increased in the liver in rats that received Ezetimibe^[7].

References:
[1] Twala C, Malindisa S, Munnik C, Sooklal S, Ntwasa M. Ezetimibe Anticancer Activity via the p53/Mdm2 Pathway. Biomedicines. 2025 Jan 14;13(1):195.
[2] Olmastroni E, Scotti S, Galimberti F, Xie S, Casula M. Ezetimibe: Integrating Established Use with New Evidence - A Comprehensive Review. Curr Atheroscler Rep. 2024 Nov 25;27(1):10.
[3] Lee D H, Han D H, Nam K T, et al. Ezetimibe, an NPC1L1 inhibitor, is a potent Nrf2 activator that protects mice from diet-induced nonalcoholic steatohepatitis. Free Radic Biol Med. 2016 Sep 12;99:520-532. 
[4] Xue J F, Lou X R, Ning D Y, et al. Ezetimibe protects against alpha-amanitin-induced hepatotoxicity by targeting the NTCP receptor: Mechanistic insights from in vitro and in vivo models. Toxicon. 2025 Sep:264:108423.
[5] Arafa M F, Alshaikh R A, Abdelquader M M, Maghraby G M E. Co-processing of Atorvastatin and Ezetimibe for Enhanced Dissolution Rate: In Vitro and In Vivo Correlation. AAPS PharmSciTech. 2021 Jan 31;22(2):59.
[6] Cho Y Q, Kim R H, Park H K, et al. Effect of Ezetimibe on Glucose Metabolism and Inflammatory Markers in Adipose Tissue. Biomedicines. 2020 Nov 18;8(11):512.
[7] Chang E, Kim L, Park S E. et al. Ezetimibe improves hepatic steatosis in relation to autophagy in obese and diabetic rats. World J Gastroenterol. 2015 Jul 7;21(25):7754-63.

Ezetimibe是一种选择性胆固醇吸收抑制剂，对肺癌细胞(A549)和人胚肾细胞(HEK293)的IC₅₀为50µM，对黑色素瘤细胞(A375)的IC₅₀为30µM，作用时间均为48h^[1]。Ezetimibe主要通过阻断小肠中的Niemann-Pick C1-Like 1(NPC1L1)蛋白，减少饮食和胆汁胆固醇的肠道吸收，进而降低低密度脂蛋白胆固醇(LDL-C)水平^[2]。

体外实验中，Hepa1c1c7(小鼠肝癌)和MEF(小鼠胚胎成纤维细胞)细胞经Ezetimibe(50μM)处理18h。Ezetimibe增强了Nrf2的转录激活；Ezetimibe还以p62依赖方式上调Nrf2靶基因，包括GSTA1、血红素氧合酶-1(HO-1)和Nqo-1。饱和脂肪酸PA可诱导ROS介导的细胞凋亡。Hepa1c1c7细胞先用Ezetimibe(50μM)预处理1h，再在PA存在下孵育18h后，细胞死亡率、凋亡细胞数及TUNEL阳性细胞均显著降低。Ezetimibe通过p62磷酸化介导的Nrf2激活，抑制PA诱导的细胞凋亡^[3]。钠牛磺胆酸共转运多肽(NTCP)是肝细胞胆汁酸转运蛋白，可介导α-鹅膏蕈碱进入肝细胞。人正常肝细胞(L-02)和人肝细胞癌细胞(HepG2)与Ezetimibe(1–6μM)共培养48h后，Ezetimibe显著提高α-鹅膏蕈碱刺激后肝细胞的存活率，并通过抑制NTCP降低炎症因子水平；Ezetimibe治疗还显著减轻氧化应激，表现为血清超氧化物歧化酶(SOD)和过氧化氢酶(CAT)升高，丙二醛(MDA)下降，提示Ezetimibe缓解α-鹅膏蕈碱诱导的氧化应激[4]。

体内实验中，白化小鼠每日口服Ezetimibe 2.5mg/kg或atorvastatin(5mg/kg)与Ezetimibe(2.5mg/kg)的物理混合物，持续2周。两药联合给药较单药进一步降低血清胆固醇水平，这归因于atorvastatin抑制肝脏胆固醇生物合成的限速酶HMG-CoA还原酶，与抑制小肠胆固醇吸收的Ezetimibe产生协同药理效应^[5]。6周龄Wistar大鼠随机分为Ezetimibe组和对照组，对照组给予高脂饮食(60Kcal%)，Ezetimibe组给予含160mg/kg Ezetimibe的高脂饮食(60Kcal%)，持续14周。Ezetimibe减小内脏脂肪脂肪细胞体积，减少促炎细胞因子积聚并诱导抗炎细胞因子产生，促进脂肪酸氧化，降低游离脂肪酸水平，改善胰岛素抵抗^[6]。肥胖糖尿病OLETF雄鼠每日经胃管给予PBS或Ezetimibe(10mg/kg)，持续20周。Ezetimibe显著降低肝脏重量及肝组织中甘油三酯(TG)、游离脂肪酸(FFA)和总胆固醇(TC)水平；肝脏自噬相关mRNA(ATG5、ATG6、ATG7)表达及微管相关蛋白轻链3(LC3)蛋白水平显著升高^[7]。