Significance of bilayer-forming phospholipids for skeletal muscle insulin sensitivity and mitochondrial function

Phosphatidylcholine (PC) and phosphatidylethanolamine (PE), which make up the bulk of mammalian cell membrane phospholipids, are recognized for their importance in metabolic health. Perturbations in the ratio of PC:PE can affect membrane integrity and function, which thus have serious health consequences. Imbalance in the hepatic PC and PE membrane content can be linked to metabolic disturbances such as ER stress, fatty liver and insulin resistance. Given that impaired insulin sensitivity underlies the pathology of many metabolic disorders and skeletal muscle is a significant regulator of energy metabolism, it is likely that aberrant phospholipid metabolism in skeletal muscle affects whole-body insulin sensitivity. Sarco/endoplasmic reticulum Ca²⁺ ATPase (SERCA) activity and mitochondrial function respond to alterations in PC:PE ratio and are associated with glucose homeostasis. Moreover, PC and PE content within the mitochondrial membrane influence mitochondrial respiration and biogenesis and thus, metabolic function. As skeletal muscle phospholipids respond to stimuli such as diet and exercise, understanding the implications of imbalances in PC:PE ratio is of great importance in the face of the rising epidemic of obesity related diseases. This review will summarize the current state of knowledge signifying the links between skeletal muscle PC:PE ratio and insulin sensitivity with respects to PC and PE metabolism, SERCA activity, mitochondrial function and exercise.     

122例酒精性肝病患者的临床研究

目的探讨酒精性肝病患者的治疗方法与临床疗效。方法回顾性分析我院收治的122例酒精性肝病患者的临床资料,所有患者随机分为2组,实验组61例患者在常规治疗的基础上采用阿托莫兰联合易善复进行治疗,对照组61例患者采用常规治疗的方法进行治疗。治疗结束后观察2组的临床疗效。结果实验组的疗效明显高于对照组,2组差异有统计学意义（P〈0.05）。结论阿托莫兰联合易善复治疗酒精性肝病疗效肯定,能明显改善酒精性肝病患者的临床症状,并促进黄疸的消退,促进肝功能恢复。     

Sphingomyelin metabolism in erythrocyte membrane in asthma

Background. Sphingomyelin (SM), a major lipid constituent of outer leaflet of plasma membranes, with cholesterol, constitutes microdomains, which are termed as lipid rafts. These rafts provide support to proteins, receptors, enzymes, and so on and organize and orient them to conduct cellular functions including transmembrane signaling to substances in external milieu. The SM contents are regulated by its metabolism, changes in which may affect the composition of lipid rafts and cell response to the triggers of asthma which may lead to the pathophysiology. For studying changes in membranes, erythrocytes, which contain lipid rafts, are considered to be the best cell type. Hence, this study was conducted on plasma membrane of erythrocytes of asthmatic patients. Objective. The objective is to understand the changes in SM metabolism in asthma. Methods. The study included 50 subjects (25 asthmatics and 25 healthy subjects). Erythrocytes were isolated from the peripheral blood and membrane prepared. This was followed by determination of total cholesterol, phospholipids, SM, and sphingomyelinase activity. P < .05 was considered significant. Results and conclusions In asthmatics, there was a significant decrease in cholesterol contents (p < .05), decrease in total phospholipid contents (p < .005), increase in SM (p < .01), decrease in cholesterol: SM ratio (p < .001) and increase in sphingomyelinase activity (p < .001) in erythrocyte membranes. We conclude that in asthma, the increase in SM contents is associated with increased sphingomyelinase activity which shows an imbalance in SM metabolism, directed toward its accumulation. The ratio of cholesterol to SM, critical for maintenance of lipid rafts, was significantly lower in asthmatics. This indicates changes in structure of lipid rafts which may lead to the pathophysiology and development of asthma. Regulation of SM metabolism may help in disease regulation and its control.     

Cardiovascular Tissue Phospholipid Metabolism in the Dahl Rat: Influence of Dietary Salt

Cardiac and thoracic aortic tissue were removed from 8-9 week old Dahl salt resistant (DR) and salt sensitive (DS) rats following 2 and 4 weeks of 8% NaCI diets. The tissue was used to determine the pool size and rate of [³²P] Pi incorporation into phosphatidylinositol-4-5-bisphosphate (PIP₂), phosphatidylinositol-4-phosphate (PIP) and phosphatidic acid (PA). The studies show no strain differences in the pool size of these phospholipids nor any changes in pool size as a consequence of the duration of exposure to the 8% NaCI diet. However, [³²P] Pi incorporation into PIP₂, PIP and PA was increased in the cardiac tissue isolated from both DR and DS rats exposed to 4 versus 2 weeks of 8% NaCI diet prior to sacrifice. The relative increase was comparable in both strains. Further, the extent of [³²P] Pi incorporation into these phospholipids was also increased in the aorta of DR, but not DS, rats exposed to 8% NaCI diets for 4 versus 2 weeks. The present study defines a strain specific difference in aortic tissue response to prolonged 8% NaCI diet exposure.     

Experimental immunotherapeutic approaches for atherosclerosis

Therapeutic options in atherosclerosis have largely been limited to the control of risk factors, such as hypercholesterolemia, hypertension, or diabetes. However, atherosclerosis is a chronic inflammatory disease in which dyslipidemia and inflammation are equally involved in disease pathogenesis. Moreover, abundant epidemiological and experimental evidence point to an important modulatory role of innate and adaptive immunity in atherogenesis, providing novel therapeutic targets for this disease. Indeed, there is now accumulating data in animal models demonstrating the potential for immunotherapeutic approaches to treat atherosclerosis. These include both general and antigen-specific ways of modulating immune functions, and they show great promise for the development of alternative and/or adjuvant therapies for atherosclerosis.     

Elevated concentrations of linoleic acid in erythrocyte membrane phospholipids in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn disease (CD), is a disorder characterized by diffuse inflammation of the gastrointestinal tract. The immune response and inflammation are mediated by polyunsaturated fatty acids and influenced by dietary fats and lipid metabolism. This study examined the qualitative and quantitative fat intake of IBD patients and healthy controls on plasma phospholipid and erythrocyte membrane phospholipid (EMP) fatty acid content. Measurement of the fatty acid composition of plasma phospholipid and EMP were performed in 29 UC patients, 20 CD patients, and 31 healthy controls. Anthropometric characteristics and data on dietary intake were also collected. We observed significantly lower lipid intake in UC and CD patients vs controls. The UC and CD patients had significantly higher levels of linoleic acid in their EMP than did controls. There were no significant differences in the levels of n-3 polyunsaturated fatty acids, but there were significantly higher levels of the n-6 in the EMP of UC and CD patients compared with controls. The significant differences persisted after the data were adjusted for potential confounders and lipid intake. Higher levels of linoleic acids and n-6 fatty acids, which are involved in production of proinflammatory mediators, were found in IBD patients compared with controls, thereby implicating n-6 fatty acids in the pathophysiology of the disease.     

氟对SH-SY5Y神经细胞生物膜性脂质的作用

目的：深入了解氟中毒对神经细胞中生物膜性脂质结构的影响及其改变机制。方法：体外培养SH-SY5Y人脑神经母细胞瘤细胞，在培养液中加入不同浓度的氟化物或加入抗氧化剂，培养48h后用测定细胞MTT的方法来了解细胞的损伤程度，用高效液相色谱法分离和测定培养液中脂质过氧化物水平，用过柱和比色法测定细胞生物膜磷脂含量，用高效液相色谱法测定细胞生物膜辅酶Q和胆固醇含量。结果：经氟处理的神经细胞中MTT水平降低和脂质过氧化水平升高，呈现剂量依赖关系；高浓度氟处理的神经细胞中磷脂和辅酶Q含量减少，但胆固醇含量不变；加入维生素E后可减弱高剂量氟对生物膜性脂质的破坏作用。结论：氟中毒可引起SH-SY5Y神经母细胞瘤细胞生物膜性脂质结构发生异常改变，其机制可能与高剂量氟引起的自由基增多而对细胞生物膜造成的损害有关。     

活性磷脂延缓果蝇老化的实验研究

目的探讨活性磷脂对果蝇的延缓老化作用及其机理。方法将未交配的果蝇随机分为4组,给予含不同浓度活性磷脂的培养基喂养。结果活性磷脂能显著延长果蝇的平均寿命和最高寿命。结论活性磷脂具有延缓果蝇老化的作用。     

兔脑磷脂的抗炎与免疫调节作用

兔脑磷脂(RBP)100～200 mg·kg~(-1)ip或sc,对4种急性渗出性炎症模型均有显著的抗炎作用,卵磷脂和脑磷脂为RBP抗急性炎症的有效成分.但RBP对慢性增生性炎症无抗炎作用.对正常和免疫受抑动物,RBP能增加脾重,提高碳粒廓清率和腹腔巨噬细胞的吞噬指数,提高淋巴细胞转化率和溶血素抗体生成及肝细胞.cGMP含量.在体外,小剂量RBP促进正常人淋巴细胞增殖反应,大剂量呈抑制作用.