人参皂苷Rg1通过调节脂肪代谢改善非酒精性脂肪肝病大鼠的肝功能

目的:研究人参皂苷Rg1对高脂饮食(HFD)诱导的非酒精性脂肪肝病(NAFLD)大鼠肝脏β-氧化的作用。方法:60只SD大鼠随机分为对照组(CON)、HFD组、人参皂苷Rg1低、中、高剂量干预组(LDG、MDG及HDG)及阳性药物熊去氧胆酸钠治疗组(PDT)。HFD8周后成功复制NAFLD模型,之后用相应药物治疗,治疗4周和8周后分别处死大鼠各半,收集肝脏做切片HE染色,同时检测其肝功能和血脂指标,RT-PCR及Westernblotting测定肝脏脂酰CoA合成酶1(CoASH1)、肉毒碱脂酰转移酶I(CATI)及脂酰CoA氧化酶1(ACOX1)mRNA和蛋白的表达。结果:治疗4周后,肝脏HE染色除HDG组有改善外,PDT组、LDG组及MDG组的脂肪肝浸润现象没有改善;治疗8周后,PDT组与LDG组仍有少量脂肪颗粒聚集,而MDG组和HDG组则看不到脂滴浸润现象;治疗4周后,PDT组、LDG组、MDG组及HDG组与HFD组相比,肝功能指标AST、ALT、AKP以及血脂指标TC、TG、LDL-C明显降低(P<0.05),治疗8周后进一步降低;治疗4周后,4个治疗组HDL-C均明显升高,8周后几乎恢复到CON组的水平;治疗4周后4个治疗组肝脏组织的CoASH1、CACTI及ACOX1表达均有显著升高(P<0.05),治疗8周后改善更为明显,同时MDG组与HDG组表达要高于PDT组(P<0.05)。结论:人参皂苷Rg1可通过调节大鼠β-氧化相关的酶改善脂肪代谢对NAFLD大鼠的肝损伤,从而发挥治疗作用。     

一例肉碱棕榈酰转移酶1A缺乏症患儿的临床及CPT1A基因变异研究

目的分析一例肉碱棕榈酰转移酶1A(carnitine palmitoyl transferase 1A,CPT1A)缺乏症患儿的临床资料、代谢筛查和基因变异特征,探讨该病的诊断要点和分子遗传学发病机制。方法收集2018年5月就诊于湖南省儿童医院神经内科的一例以癫痫起病的CPT1A缺乏症患儿的临床资料及其血液酰基肉碱结果,采集患儿和父母外周血,提取DNA行基因检测。结果血液酰基肉碱谱提示游离肉碱(carnitine 0,C0)升高,C0/(C16+C18)明显升高。基因测序结果显示患儿CPT1A基因c.1846G>A和c.2201T>C复合杂合变异,母亲携带c.1846G>A变异,父亲携带c.2201T>C变异。结论本例CPT1A缺乏症患者以癫痫为第一临床表现发病,国内外暂未见相关报道。血液酰基肉碱分析是筛查和诊断CPT1A缺乏症的必要条件,二代测序有助于该病的确诊。CPT1A基因c.1846G>A和c.2201T>C变异可能为该患儿致病原因,c.1846G>A变异为未报道过的新变异,丰富了CPT1A基因变异谱。     

线粒体脂肪酸氧化缺陷与能量代谢研究

线粒体脂肪酸氧化(fatty ac id oxidation,FAO)在能量产生中起重要作用,尤其在饥饿时。线粒体FAO过程非常复杂,经过细胞摄取脂肪酸、活化、转脂化作用,通过线粒体膜、再脂化,线粒体内-氧化、电子产生和转运以及乙酰辅酶A在肝脏内形成酮体等约20个步骤,其中任何一个代谢途径异常     

新生儿筛查发现的游离肉碱降低33例分析及临床随访

目的 了解湖北省妇幼保健院游离肉碱降低所致的遗传代谢病病种分布特征、发病率、基因突变特征及确诊病例的临床转归。方法 对2017年12月至2022年9月在湖北省妇幼保健院新筛中心应用串联质谱技术进行筛查的新生儿205876例,完善酰基肉碱谱检测,初筛阳性者召回复查,仍阳性者同时检测患儿母亲游离肉碱,行高精准度二代测序技术明确诊断,并对确诊病例进行临床随访。结果 在205876例新生儿中,初筛游离肉碱降低33例,其中原发性肉碱缺乏症15例,母源性肉碱缺乏症6例,SLC22A5基因携带者6例,假阳性5例,继发性肉碱缺乏1例,1例失访。检测到16种SLC22A5基因突变,热点突变是c.1400C>G和c.51C>G,首次报道了c.403G>A和c.1540G>C这种新发突变。结论 新生儿串联质谱筛查是识别包括原发性肉碱缺乏症在内的遗传代谢病的有效方法,新生儿筛查游离肉碱降低最常见于原发性肉碱缺乏症,但也可以由其他代谢性疾病所继发,结合基因分析有助于明确诊断,并需排除假阳性及假阴性。我们的发现丰富了以游离肉碱降低为生化表现的遗传代谢病病种及基因突变谱,并为家系遗传咨询及产...     

Salusin-α转染血管平滑肌细胞对ACAT1和SA-R表达的调节作用

目的:探讨Salusin-α基因转染血管平滑肌细胞对乙酰辅酶A乙酰转移酶1(ACAT1)及清道夫受体(SA-R)表达的影响。方法:构建pcDNA3.1-Salusin-α-EGFP(EGFP为绿色荧光蛋白)和psiHIV-U6-Salusin-α质粒(psiHIV-U6为慢病毒RNA干扰载体)。分别转染pcDNA3.1-Salusin-α-EGFP质粒和psiHIV-U6-Sa-lusin-α质粒至氧化低密度脂蛋白(oxLDL)诱导培养的血管平滑肌细胞(VSMCs),并设置对照组,于37℃5%CO2培养箱中培养48h后,用Western-blotting方法检测ACAT1及SA-R的表达。结果:成功构建pcDNA3.1-Salusin-α-EGFP和psi-HIV-U6-Salusin-α质粒。转染pcDNA3.1-Salusin-α-EGFP入VSMCs,Salusin-α表达增加,ACAT1表达降低(P<0.05)。转染psiHIV-U6-Salusin-α入VSMCs,Sa-lusin-α降低表达,ACAT1表达增加(P<0.05)。同时转染pcDNA3.1-Salusin-α-EGFP和psiHIV-U6-Salusin-α入VSMCs,Salusin-α和ACAT1表达均无显著性变化(P>0.05)。Salusin-α表达增加或降低对SA-R的表达均无明显影响(P>0.05)。结论:Salusin-α可下调ACAT1表达,可能具有抗动脉粥样硬化的作用。     

运动与脂肪氧化动力学特征的应用启示

背景：当下降脂减肥已成为一个永恒的话题,运动作为降脂的重要手段,探讨影响运动中脂肪代谢的因素成为研究的热点。目的：探究运动方式、运动强度和运动时间对脂肪氧化动力学特征的影响,归纳总结运动调控脂肪氧化的生物学机制,探索合理运动处方在防治肥胖等代谢性疾病中的应用启示,并瞻望该领域的未来研究方向。方法：通过中国知网(CNKI)、百链云图书馆、PubMed和EBSCO运动科学全文等中英文数据库及Researcher、ResearchGate学术社交平台,选取“运动;脂肪氧化;脂肪动员;脂肪代谢;减肥”及“exercise;fat metabolism;fat energy ratio;fat oxidation rate”等作为检索词分别进行中文及英文组合检索,对最终纳入的相关文献进行归类、汇总、总结与提炼。结果与结论：①脂肪氧化动力学特征是一个复杂的非线性过程,主要包括脂肪供能比例和脂肪氧化率两个方面,并受运动强度、运动时间、运动方式、运动水平、运动习惯和体成分等因素的影响,上述各因素相互关联、相互制约,并呈现出阶段性变化特征。②运动调控脂肪氧化的分子生物学机制已较为成熟,但乳酸抑制脂肪氧化的生物学机制还不完全清楚。③为提高减肥效果,建议增加每日运动量,但受能量保护机制的影响,运动减肥的时间并非越长越好。建议后续加强运动调控脂肪氧化的基础应用性研究,借助蛋白组学、基因组学和免疫组学等手段,在器官系统和细胞分子水平上,从神经调节、免疫系统控制、骨骼肌代谢、线粒体适应、肠道菌群活性以及外泌体释放等方面入手寻找科学证据,探寻相关生物学机制。https://orcid.org/0000-0001-7308-1700 (孔凡明) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

ERK1/2/PPARα/SCAD信号途径对生理性和病理性心肌肥大的调控

 目的：研究ERK1/2/PPARα/SCAD（短链脂酰辅酶A脱氢酶）信号途径对生理性和病理性心肌肥大调控的不同机制,探索病理性心肌肥大治疗的新靶点。方法：分别以胰岛素样生长因子1（insulin-like growth factor 1,IGF-1）和苯肾上腺素（phenylephrine,PE）刺激心肌细胞,复制生理性和病理性心肌肥大模型,检测心肌细胞表面积,p-ERK1/2和PPARα蛋白表达变化,SCAD mRNA、蛋白表达和酶活性变化,心肌细胞游离脂肪酸含量变化。结果：与对照组比较,PE和IGF-1刺激后心肌细胞表面积均显著增大。与对照组相比,IGF-1刺激的心肌细胞SCAD mRNA和蛋白表达均上调,酶活性显著增高,游离脂肪酸含量明显减少,且PPARα mRNA和蛋白表达均上调,p-ERK1/2的蛋白表达显著下调;PE刺激的心肌细胞SCAD mRNA和蛋白表达均下调,酶活性显著降低,游离脂肪酸含量明显增加,且PPAR αmRNA和蛋白表达均下调,p-ERK1/2蛋白表达显著上调。结论：p-ERK1/2/PPARα/SCAD在生理性和病理性心肌肥大中呈现出不一致的变化趋势,表明ERK1/2/PPARα/SCAD信号途径对2种不同肌肥大的调控作用不同。SCAD可能作为2种不同心肌肥大的分子标志物及病理性心肌肥大的潜在治疗靶点。     

线粒体脂肪酸β-氧化障碍的研究新进展

脂肪酸是机体在饥饿、应激等状态下通过线粒体内的β-氧化为机体提供能量的主要来源。线粒体中存在着催化脂肪酸氧化的多种酶,近年来研究已发现在脂肪酸β-氧化过程有20余种参与的活性酶,相应酶的活性缺陷导致临床一系列脂肪酸氧化障碍。在脂肪酸β-氧化过程易出现障碍的环节主要涉及到脂肪酸和肉碱转运障碍,各种酰基辅酶A脱氢酶缺陷,线粒体基质内β-氧化所需的各种酶的功能障碍,酮体生成障碍等。临床上常表现为低血糖,心肌病,肌张力低下,酸中毒,猝死,脑病等症状。随着串联质谱技术在高危新生儿遗传代谢病筛查中的应用,使得此类疾病能够得到快速准确的诊断,做到早期发现,早期治疗,从而明显的改善疾病的预后。     

羟酰辅酶A脱氢酶在癌中作用机制的研究进展

脂肪酸代谢与癌的发生发展之间存在密切联系。羟酰辅酶A脱氢酶(HADH)作为脂肪酸β-氧化的关键酶,近年来被发现在多种癌中为抑癌因子,在急性髓系白血病等中为促癌因子。在癌细胞中,HADH除直接催化脂肪酸β-氧化外,还间接作用于PPAR、TNF-α、JAK-STAT3、PI3K/Akt、IFN-γ、MAPK与非经典Wnt等多种信号通路,影响癌细胞增殖与迁移。HADH作为不同种癌诊断、治疗和预后的潜在肿瘤标志物,具备较高临床应用价值。     

骨量及骨代谢中胰岛素生长因子1、转化生长因子β和白细胞介素6在长期递增负荷运动状态下的变化

背景：研究表明,合理的适量运动能够促进骨量,相反过量运动会影响骨量的蓄积,但负荷过量的运动对骨代谢的影响作用机制目前仍不清楚。 目的：探讨长期递增负荷运动对骨量的影响效应,以及对骨代谢的影响作用机制。 方法：将SD大鼠分别进行4,9,11,13,15,17周的递增负荷运动,并设置对照组,以放射免疫分析法测定各组大鼠雌二醇水平,以酶联免疫法测定各组血清胰岛素生长因子1,转化生长因子β及白细胞介素6的浓度,以双能X射线骨密度仪测定各组骨密度水平。 结果与结论：和同期对照组相比,胰岛素生长因子1和转化生长因子β在运动后9和17周显著降低(P < 0.05),转化生长因子β在运动第4周显著升高(P < 0.05),白细胞介素6在运动第9,15,17周均显著升高(P < 0.05)。雌二醇水平在运动第13,15和17周降低(P < 0.05或P < 0.01),全身骨密度值在运动第15,17周显著降低(P < 0.01)。结果证实,长期递增负荷运动导致大鼠机体骨代谢发生改变,由骨形成占优势过渡为骨吸收占优势,最终出现骨密度值降低,骨代谢平衡向破骨方向倾斜的重要致因与过量运动所造成的性腺轴功能受抑,雌二醇水平降低有关。     

Substrate oxidation and cardiac performance during exercise in disorders of long chain fatty acid oxidation

BackgroundThe use of long-chain fatty acids (LCFAs) for energy is inhibited in inherited disorders of long-chain fatty acid oxidation (FAO). Increased energy demands during exercise can lead to cardiomyopathy and rhabdomyolysis. Medium-chain triglycerides (MCTs) bypass the block in long-chain FAO and may provide an alternative energy substrate to exercising muscle.ObjectivesTo determine the influence of isocaloric MCT versus carbohydrate (CHO) supplementation prior to exercise on substrate oxidation and cardiac workload in participants with carnitine palmitoyltransferase 2 (CPT2), very long-chain acyl-CoA dehydrogenase (VLCAD) and long-chain 3-hydroxyacyl CoA dehydrogenase (LCHAD) deficiencies.DesignEleven subjects completed two 45-minute, moderate intensity, treadmill exercise studies in a randomized crossover design. An isocaloric oral dose of CHO or MCT-oil was administered prior to exercise; hemodynamic and metabolic indices were assessed during exertion.ResultsWhen exercise was pretreated with MCT, respiratory exchange ratio (RER), steady state heart rate and generation of glycolytic intermediates significantly decreased while circulating ketone bodies significantly increased.ConclusionsMCT supplementation prior to exercise increases the oxidation of medium chain fats, decreases the oxidation of glucose and acutely lowers cardiac workload during exercise for the same amount of work performed when compared with CHO pre-supplementation. We propose that MCT may expand the usable energy supply, particularly in the form of ketone bodies, and improve the oxidative capacity of the heart in this population.     

Role of fatty acid oxidation in mechanism of action of gastric secretagogues

The role of beta-oxidation in the mechanism of stimulation of acid secretion was examined in toad gastric mucosa in vitro. The incubation with 4-pentenoate selectively inhibited in a dose-dependent manner the rate of 14CO2 formation from [1-14C]octanoate. Pretreatment with 20 mM 4-pentenoate sharply reduced the respiratory and secretory responses to theophylline and histamine. Tracer studies showed a major utilization of exogenous octanoate over glucose and pyruvate by the in vitro toad gastric mucosa. Theophylline and histamine stimulated by 69% the rate of octanoate oxidation. Over 60% of the increments in oxygen uptake produced by theophylline and histamine accounted for the increments in octanoate oxidation, whereas glucose and pyruvate together accounted for less than 25%. Octanoate-dependent respiration was shown to correlate with octanoate oxidation under both inhibition with 4-pentenoate and stimulation with theophylline. Theophylline stimulated by 25% the rate of octanoate oxidation in Cl--free glucuronate-nutrient solutions. The present work provides further evidence for the primary role of fatty acid oxidation in the mechanism of acid secretion in amphibian.     

Reduced plasma free fatty acid availability during exercise: effect on gene expression

Endurance exercise transiently increases the mRNA of key regulatory proteins involved in skeletal muscle metabolism. During prolonged exercise and subsequent recovery, circulating plasma fatty acid (FA) concentrations are elevated. The present study therefore aimed to determine the sensitivity of key metabolic genes to FA exposure, assessed in vitro using L6 myocytes and secondly, to measure the expression of these same set of genes in vivo, following a single exercise bout when the post-exercise rise in plasma FA is abolished by acipimox. Initial studies using L6 myotubes demonstrated dose responsive sensitivity for both PDK4 and PGC-1α mRNA to acute FA exposure in vitro. Nine active males performed two trials consisting of 2 h exercise, followed by 2 h of recovery. In one trial, plasma FA availability was reduced by the administration of acipimox (LFA), a pharmacological inhibitor of adipose tissue lipolysis, and in the second trial a placebo was provided (CON). During the exercise bout and during recovery, the rise in plasma FA and glycerol was abolished by acipimox treatment. Following exercise the mRNA abundance of PDK4 and PGC-1α were elevated and unaffected by either acipimox or placebo. Further analysis of skeletal muscle gene expression demonstrated that the CPT I gene was suppressed in both trials, whilst UCP-3 gene was only modestly regulated by exercise alone. Acipimox ingestion did not alter the response for both CPT I and UCP-3. Thus, this study demonstrates that the normal increase in circulating concentrations of FA during the later stages of exercise and subsequent recovery is not required to induce skeletal muscle mRNA expression of several proteins involved in regulating substrate metabolism.     

Effect of carnitine loading on long-chain fatty acid oxidation,maximal exercise capacity,and nitrogen balance

Summary Carnitine has a potential effect on exercise capacity due to its role in the transport of long-chain fatty acids into the mitochondria for-oxidation, the export of acyl-coenzyme A compounds from mitochondria and the activation of branched-chain amino acid oxidation in the muscle. We studied the effect of carnitine supplementation on palmitate oxidation, maximal exercise capacity and nitrogen balance in rats. Daily carnitine supplementation (500 mg - kg^–1 body mass for 6 weeks) was given to 30 rats, 15 of which were on an otherwise carnitine-free diet (group 1) and 15 pair-fed with a conventional pellet diet (group II). A control group (group III,n = 6) was fed ad libitum the pellet diet. Palmitate oxidation was measured by collecting¹⁴CO₂ after an intraperitoneal injection of [1-¹⁴C]palmitate and exercise capacity by swimming to exhaustion. After carnitine supplementation carnitine concentrations in serum were supranormal [group I, total 150.8 (SD 48.5), free 78.9 (SD 18.4); group II, total 170.9 (SD 27.9), free 115.8 (SD 24.6) gmol·1^–1] and liver carnitine concentrations were normal in both groups [group I, total 1.6 (SD 0.3), free 1.2 (SD 0.2); group II, total 1.3 (SD 0.3), free 0.9 (SD 0.2) mol·g^–1 dry mass]. In muscle carnitine concentrations were normal in group I [total 3.8 (SD 1.2), free 3.2 (SD 1.0) mol · g^–1 dry mass] and increased in group II [total 6.6 (SD 0.5), free 4.9 (SD 0.9) mol·g^–1 dry mass]. Despite the difference in muscle carnitine concentrations there were no differences among the groups in cumulative palmitate oxidation after 3 h [group I, 39.7 (SD 11.6)%, group II, 29.6 (SD 14.0)%; group III, 36.5 (SD 10.8)% of injected activity] or swimming time to exhaustion [group I, 9.7 (SD 2.9); group II, 8.4 (SD 3.6); group III, 7.1 (SD 2.8) h]. A borderline increase in nitrogen balance was observed in group II. We concluded that increasing carnitine tissue concentrations by carnitine supplementation had no effect on palmitate oxidation and maximal exercise capacity in the rats studied.