PPARs:脂代谢调节与胰岛素增敏治疗药物的作用靶标

过氧化物酶体增殖物激活受体 (PPARs)是核受体超家族成员之一。PPARα、PPARγ可分别被氯贝特类和TZD类药物特异性激活 ,调节脂代谢、改善胰岛素抵抗 ;有研究表明PPARβ也参与脂肪代谢。因此 ,以PPARs为药物靶标 ,发现和优化单一或双重激动剂将为肥胖和 2型糖尿病的预防和治疗提供有效药物     

糖尿病和动脉粥样硬化发病机制的交会点-PPARs

糖尿病作为冠心病危险等同因素，糖尿病人易患动脉粥样硬化，其分子机制过去所知甚少，近年来对过氧化物酶体增殖物激活受体（PPARs）研究进展很快，对其在糖尿病和动脉粥样硬化发病机制中的作用有了新的发现和认识。本文就该方面的研究进展综述如下。     

中医药干预PPARs及其通路治疗冠心病的研究进展

过氧化物酶增殖物激活受体(PPARs)作为一类由配体激活的核转录因子超家族成员,属于Ⅱ型核受体超家族,控制细胞内多种代谢过程,具有广泛的生理和病理学功能。PPARs具有调节与脂代谢和葡萄糖代谢相关基因的功能,可直接下调促炎基因转录或间接影响脂代谢的转录效应来调控炎症反应。PPARs具有多效性,参与多种疾病的病理形成过程,例如肥胖、糖尿病、冠心病以及某些肿瘤疾病,因此是多种疾病的重要治疗靶点。文章就PPARs与冠心病的发生发展关系以及中药的干预作用作一概述。     

AMPK、PPARs在2型糖尿病中的作用机制及药物研究

2型糖尿病（T2DM）在全球范围内广泛流行,其主要特征为胰岛素抵抗和胰腺β细胞分泌的胰岛素减少,糖脂代谢发生紊乱,其发病原因是多因素的。AMPK和PPARs作为体内代谢过程的关键调节因子,对糖脂代谢平衡有着巨大贡献。本文着重综述两者在2型糖尿病发生发展中的作用机制,以及相应的药物对2型糖尿病的治疗效果和作用机制,以期为2型糖尿病药物的研发提供参考。     

游离脂肪酸与脂毒性

短期游离脂肪酸升高可促进基础胰岛素分泌，长期游离脂肪酸升高抑制基础胰岛素释放，称为“脂毒性”。不同游离脂肪酸对胰岛β细胞的不同作用。瘦素作用缺陷是脂毒性形成的重要原因。长期游离脂肪酸通过影响基础胰岛素信号转导通路中基因表达、葡萄德与脂肪酸代谢中关键酶的表达，转录因子PPARs、解偶联蛋白—2、AIP敏感的钾离子通道和一些凋亡通路致使β细胞功能下降，β细胞凋亡。研究脂毒性对阻止2型糖尿病发展及治疗糖尿病的脂代谢异常均有重要意义。     

Variable effects of anti-diabetic drugs in animal models of myocardial ischemia and remodeling: A translational perspective for the cardiologist

Diabetes and heart failure are very prevalent, and affect each other's incidence and severity. Novel therapies to reduce post-myocardial infarction (MI) remodeling that progresses into heart failure are urgently needed, especially in diabetic patients. Clinical studies have suggested that some oral anti-diabetic agents like metformin exert cardiovascular protective effects in heart failure patients with diabetes, whereas other agents may be deleterious. In the current review, we provide an overview of the cardio-specific effects of oral anti-diabetic drugs in animal models of acute MI, post-MI remodeling, and heart failure. Metformin has consistently been shown to ameliorate cardiac remodeling after ischemia/reperfusion (I/R) injury, as well as in several models of heart failure. Sulfonylurea derivatives are controversial with respect to their direct effects on the cardiovascular system. Thiazolidinediones protect against myocardial I/R injury, but their effects on post-MI remodeling are less clear and clinical studies raised concerns about their cardiovascular safety. Glucagon-like peptide-1 analogs have potential beneficial effects on the cardiovascular system that require further confirmation, whereas the results with dipeptidyl peptidase-4 inhibitors are equivocal. Current clinical guidelines, in the absence of prospective clinical trials that evaluated if certain oral anti-diabetic agents are superior over others, only provide generic recommendations, and do not take into account interesting experimental and mechanistic data. The available experimental evidence indicates that some anti-diabetic agents should be preferred over others if cardio-protective effects are warranted. These experimental clues need to be confirmed by clinical trials.     

Anti-obesity efficacy of LH-21, a cannabinoid CB(1) receptor antagonist with poor brain penetration, in diet-induced obese rats

BACKGROUND AND PURPOSE

Peripheral blockade of cannabinoid CB₁ receptors has been proposed as a safe and effective therapy against obesity, putatively devoid of the adverse psychiatric side effects of centrally acting CB₁ receptor antagonists. In this study we analysed the effects of LH-21, a peripherally acting neutral cannabinoid receptor antagonist with poor brain penetration, in an animal model of diet-induced obesity.

EXPERIMENTAL APPROACH

To induce obesity, male Wistar rats were fed a high-fat diet (HFD; 60 kcal% fat) whereas controls received a standard diet (SD; 10 kcal% fat). Following 10 weeks of feeding, animals received a daily i.p. injection of vehicle or 3 mg·kg⁻¹ LH-21 for 10 days. Plasma and liver samples were used for biochemical analyses whereas visceral fat-pad samples were analysed for lipid metabolism gene expression using real-time RT-PCR. In addition, the potential of LH-21 to interact with hepatic cytochrome P450 isoforms and cardiac human Ether-à-go-go Related Gene (hERG) channels was evaluated.

KEY RESULTS

LH-21 reduced feeding and body weight gain in HFD-fed animals compared with the control group fed SD. In adipose tissue, this effect was associated with decreased gene expression of: (i) leptin; (ii) lipogenic enzymes, including SCD-1; (iii) CB₁ receptors; and (iv) both PPARα and PPARγ. Although there were no significant differences in plasma parameters between HFD- and SD-fed rats, LH-21 did not seem to induce hepatic, cardiac or renal toxicity.

CONCLUSIONS AND IMPLICATIONS

These results support the hypothesis that treatment with the peripherally neutral acting CB₁ receptor antagonist, LH-21, may promote weight loss through modulation of visceral adipose tissue.     

PPAR激动剂在治疗非酒精性脂肪性肝病中的应用前景

由于肥胖症和2型糖尿病患者越来越多,非酒精性脂肪性肝病(NAFLD)也呈现逐年上升趋势。NAFLD可引起肝硬化和肝癌等并发症,严重威胁公众健康,目前尚无有效治疗NAFLD及其并发症的药物。肝脏甘油三酯聚集是NAFLD的重要标志,过氧化物酶体增殖物活化受体(PPAR)可参与脂代谢、糖代谢以及炎症的调控。本文综述了PPAR参与NAFLD的可能作用机制以及治疗NAFLD的PPAR激动剂的研究进展。