脂质比值与代谢综合征的关联及预测价值评价：基于多阶段横断面研究

背景 随着代谢性疾病发病率的上升,代谢综合征(MS)的预防与控制引起广泛的关注。而脂质比值是重要的筛查指标之一,与MS之间的关系成为热点研究话题。目的 基于贵州省多阶段横断面研究人群分析三酰甘油/高密度脂蛋白胆固醇(TG/HDL-C)、总胆固醇/HDL-C(TC/HDL-C)、低密度脂蛋白胆固醇/HDL-C(LDL-C/HDL-C)及非高密度脂蛋白胆固醇(non-HDL-C)与MS发病风险的关联及预测价值评价。方法 回顾性选取贵州省参与2010年全国疾病监测地区慢性病及危险因素调查、2013年中国慢性病及其危险因素监测、2015年中国成人慢性病与营养监测和2018年中国成人慢性病与营养监测的21 727例自然人群为研究对象,收集研究对象的基线资料,根据是否患有MS将研究对象分为MS组(n=4 981)和非MS组(n=16 746)。绘制受试者工作特征曲线(ROC曲线)分别评价男性和女性TG/HDL-C、TC/HDL-C、LDL-C/HDL-C和non-HDL-C对MS的预测价值。通过Delong检验比较脂质比值预测MS发生的ROC曲线下面积(AUC)的差异。采用多因素Logistic回...     

Effects of a brisk walk on lipoprotein lipase activity and plasma triglyceride concentrations in the fasted and postprandial states

This study aimed to determine whether changes in plasma heparin-releasable lipoprotein lipase (LPL) activity following a brisk walk were associated with decreases in fasting and/or postprandial triglyceride (TG) concentrations. Two groups of pre-menopausal women participated. In one group (fasting study group, n=10), TG concentrations and post-heparin plasma LPL activity were measured in the fasted state on two occasions: ~18 h after a 2-h treadmill walk at 50% maximal oxygen uptake (exercise trial); and after a day of no exercise (control trial). The other group (postprandial study group, n=9) undertook two oral fat tolerance tests (blood samples taken fasting and for 6 h after a high-fat meal), with plasma LPL activity measured 6 h after meal ingestion. Pre-conditions were the same as for the fasting study group (i.e. control and prior exercise). Prior exercise reduced fasting TG concentrations by 23 (7)% (fasting study group) [mean (SEM)] and by 18 (9)% (postprandial study group) (both P<0.05), and the postprandial TG response by 23 (6)% (postprandial study group) (P<0.01). Plasma LPL activity was not significantly increased by exercise in either the fasting or postprandial study groups. However, exercise-induced changes in both fasting and postprandial LPL activity were significantly correlated with the respective exercise-induced changes in fasting TG concentration and the postprandial TG response (r=−0.70 and −0.77 respectively, P<0.05 for both). These data suggest that increased LPL activity may contribute to the hypotriglyceridaemic effect of moderate exercise, although other mechanisms are also likely to be involved. Electronic Publication     

Palmitic acid metabolism in the soleus muscle in vitro in hypo- and hyperthyroid rats

The aim of this study was to establish whether the rate of fatty acid (FA) incorporation and its utilization by the isolated soleus muscle is modified under conditions of thyroid hormone deficit or excess. The rate of palmitic acid (PA) uptake, oxidation and incorporation into intramuscular lipids with increasing PA concentration (0.5–1.5 mM) in the incubation medium were determined. In hypothyroid rats intramuscular triacylglycerol (TG) synthesis was increased, while the rate of PA oxidation to CO₂ and incorporation into mono- and diacylglycerols (MG/DG) and phospholipids (PL) remained unchanged. In rats with triiodothyronine (T₃) excess the rate of all processes studied was enhanced, although the percentage incorporation of PA into different classes of intramuscular lipids was fairly constant and, independently of thyroid state and FA concentration in the medium, was 56–66% for TG, 9-14% for MG/DG and 24–32% for PL. Our results thus indicate that even short-term T₃ excess accelerates the rate of FA uptake and metabolism in the oxidative soleus muscle, whereas in hypothyroid rats only intramuscular TG synthesis is affected.     

氯沙坦联合螺内酯片治疗原发性高尿酸血症并高血压的效果及对三酰甘油的影响

目的：研究氯沙坦联合螺内酯片治疗原发性高尿酸血症并高血压的效果及其对三酰甘油（TG）的影响。方法以2013年2月～2014年5月本院收治的80例原发性高尿酸血症并高血压患者为研究对象,按照随机数字表法均分为观察组与对照组,观察组给予氯沙坦联合螺内酯片治疗,对照组仅行氯沙坦治疗。连续用药8周,比较治疗前（T1）,治疗后2、4、6、8周（T2、T3、T4、T5）血压与血尿酸的变化,同时比较血TG的变化。结果两组血尿酸均得到有效控制,其水平随时间延长呈现显著下降趋势,差异有统计学意义（P＜0.05）,且从T3时刻开始,数据较T1时刻差异有统计学意义（P＜0.05）;两组各时间点血尿酸水平差异无统计学意义（P＞0.05）。两组血压均得到有效控制,舒张压及收缩压均随时间延长显著下降（P＜0.05）;但各时间点组间比较,差异无统计学意义（P＞0.05）。两组血TG水平均呈上升趋势（P＜0.05）;自T3开始,观察组血TG相较对照组更低（P＜0.05）。结论氯沙坦联合螺内酯片可有效降低原发性高尿酸血症并高血压患者的血尿酸及血压水平,同时还有助于抑制血TG升高。     

Perturbation of phospholipid and triacylglycerol fatty acid positional location in the heart of rats depleted of n-3 long-chain polyunsaturates

Rats depleted of long-chain polyunsaturated n-3 fatty acids (n-3–D) display several features of the metabolic syndrome, including obesity, liver steatosis, insulin resistance, hypertension, and cardiac hypertrophy. In this study, the heart phospholipid (PL) and triacylglycerol (TG) fatty acid content and pattern were compared between female control rats (C) and n-3–D rats. The sole n-3 fatty acids found in n-3–D rats, C22:5(n-3) and C22:6(n-3), were 10 to 20 times lower than in C. The total fatty acid content of PL was lower in n-3–D rats than C. No ectopic TG accumulation was found in n-3–D rats. In both PL and TG, the C16:0/C16:1(n-7) and C18:0/C18:1(n-9) ratios suggested increased Δ9-desaturase activity in n-3–D rats. The PL C18:2(n-6)/C20:4(n-6) and C20:4(n-6)/C22:4(n-6) ratios were also lower in n-3–D rats than C. Prior intravenous injection of a medium-chain TG:fish oil emulsion to n-3–D rats 60 to 120 minutes before killing augmented the PL content in C22:5(n-3) and C22:6(n-3), minimized the age-related decrease in the PL C18:1(n-9) relative content, and increased the TG C22:4(n-6) content. The alteration of cardiac function in n-3–D rats and its improvement after injection of medium-chain TG:fish oil emulsion coincides with parallel changes in heart lipid fatty acid content and pattern.     

平滑肌细胞双信使系统与钙火花相关性研究

在平滑肌细胞的肌醇脂质代谢中产生的肌醇三磷酸(IP3)和二酰甘油(DAG)是胞内重要的第二信使,由它们激动的IP3/Ca2+和DAG/蛋白激酶C(PKC)途径,即是调控胞内许多生理过程的重要信号途径。因此又把这一以肌醇磷脂代谢为基础的细胞信号系统称为“双信使系统”。大量研究表明,双信使系统与平滑肌细胞胞内Ca2+浓度的调节、胞内局部Ca2+释放事件、钙火花的产生和调控紧密相关。本文就此方面的研究进展进行综述。     

Mode of action of neuropeptides from the adipokinetic hormone family

Neuropeptides of the adipokinetic hormone (AKH) family regulate inter alia mobilisation of various substrates from stores in the fat body of insects during episodes of flight. How is this achieved? In insects which exclusively oxidise carbohydrates for flight (cockroaches), or which oxidise carbohydrates in conjunction with lipids (locusts) or proline (a number of beetles), the endogenous AKHs bind to a G(q)-protein-coupled receptor, activate a phospholipase C and the resulting inositol trisphosphate releases Ca(2+) from internal stores. In addition, influx of extracellular Ca(2+) is increased and, via a kinase cascade, glycogen phosphorylase is activated, glucose-1-phosphate produced, and transformed to trehalose, which is released into the haemolymph. In locusts, additionally, adenylate cyclase is activated and cyclic AMP is synthesised. In insects which use lipids for sustained flight (locust, tobacco hornworm moth) or proline for flight (certain beetles), adenylate cyclase is activated after the AKHs bind to their respective G(s)-protein-coupled receptor. The resulting cyclic AMP, together with the messengers intra- and extracellular Ca(2+), activate a triacylglycerol lipase, which results in the production of 1,2 diacylglycerols (in locusts, moths) or (hypothetically) free fatty acids (fruit beetle).     

Cerebral phosphoinositide, triacylglycerol and energy metabolism during severe hypoxia and recovery

The cerebral concentrations of phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP), phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidic acid (PA), triacylglycerol (TAG) and free fatty acids (FFA), as well as cerebral metabolites, were measured in rats subjected to 10 min of hypoxia and subsequent recovery of 7 or 30 min duration. The experiments were carried out with control of physiological variables. Hypoxia (paO2 values of about 15 mm Hg) caused a decrease in PI, whereas PIP and PIP2 did not change significantly. A two-fold increase of total FFA was noted, mainly comprising stearic and arachidonic acids. TAG-arachidonate tended to increase, but the other species in TAG decreased. Adenosine triphosphate (ATP) and energy charge (EC) decreased slightly and there was a marked lactate accumulation. PA did not change throughout the experiment. With recovery of 7 min duration, PI decreased further and total FFA continued to increase. TAG-arachidonate increased significantly. ATP remained depressed but EC recovered to the control range. Both tissue and plasma glucose increased. Tissue lactate remained elevated and systemic acidosis occurred. After a recovery period of 30 min, all lipids normalized and the energy state returned toward control. The data suggest that the phosphoinositide alterations during hypoxia are metabolically linked to changes in FFA and the lipid changes are accompanied by alterations in cerebral energy and carbohydrate metabolism. The selective increase in TAG-arachidonate may represent an incorporation of arachidonic acid into TAG, which may serve to reduce the free arachidonic acid level in the brain.     

Fatty acid metabolism in adipose tissue of aging mice after direct tracer injection into fat pads

We have examined previously reported age-related defects in triglyceride synthesis from [1-¹⁴C]palmitate in adipose tissue of mice. Three techniques were used: in vitro, using adipocytes isolated from epididymal fat pads of young and old mice; and in vivo, using two new methods to measure free fatty acid (FFA) esterification by adipose tissue (direct injection of labeled palmitate-albumin complexes in large or small volumes into the extracellular spaces of the epididymal or inguinal fat pads of young and old mice). When the entire fat pad was filled with tracer we no longer observed heterogeneous labeling of adipocytes in epididymal fat pads that occurred in an earlier study in which an in vivo-in vitro method has been used. Free fatty acids were converted to triacylglycerol faster by adipocytes of large cells from older animal than by those of small cells from young mice; when the cell sizes of young and old mice were approximately equal, then the rates of FFA esterification were the same in young and old adipocytes. When FFA was injected as a small bolus the fractional rates of FFA disappearance and of FFA incorporation into triacylglycerol in the different fat pads, observed during a 60-min period, were the same (about 5 min or less) regardless of the region of the fat pad studied (distal or proximal epididymal fat pad), the type of fat pad (epididymal or inguinal), or the age of the mice (12–92 weeks). Other potential applications of the direct injection technique for studying FFA metabolism and structure-function in adipose tissue in vivo are discussed. Our findings, coupled with the earlier study in which labeled FFA was added to the outside of fat pads, indicate that, in adipose tissue of old mice, there exist barriers comprising mesothelial cells, collagenous structures, and/or the outer layer of adipocytes in fat pads, that interfere in the transport of FFA to the interior adipocytes when FFA is added outside the fat pad. This age-related defect may be circumvented by injecting tracer directly into the interstitial fluid compartment.