Serum lipids and apolipoproteins in families of postinfarction men

The study of relatives of postinfarction patients was designed to assess the familial associations of lipids (total cholesterol, triglycerides, high density lipoprotein-cholesterol), and of apolipoproteins A and B. Examination of 493 individuals from 106 families showed only some familial associations of serum lipids between mothers and offspring and among siblings, but similar associations in apolipoproteins among all groups of direct relatives (i.e. between mothers and offspring, among siblings and between fathers and offspring). Associations among direct relatives, and their absence between spouses, suggest the genetic influence on lipoproteins. Apolipoproteins appear to be a more suitable means of detecting such associations than serum lipid levels.     

Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia-hyperaminoacidaemia in healthy young and middle-aged men and women

Increased dietary LCn-3PUFA (long-chain n-3 polyunsaturated fatty acid) intake stimulates muscle protein anabolism in individuals who experience muscle loss due to aging or cancer cachexia. However, it is not known whether LCn-3PUFAs elicit similar anabolic effects in healthy individuals. To answer this question, we evaluated the effect of 8?weeks of LCn-3PUFA supplementation (4?g of Lovaza?/day) in nine 25-45-year-old healthy subjects on the rate of muscle protein synthesis (by using stable isotope-labelled tracer techniques) and the activation (phosphorylation) of elements of the mTOR (mammalian target of rapamycin)/p70S6K (p70 S6 kinase) signalling pathway during basal post-absorptive conditions and during a hyperinsulinaemic-hyperaminoacidaemic clamp. We also measured the concentrations of protein, RNA and DNA in muscle to obtain indices of the protein synthetic capacity, translational efficiency and cell size. Neither the basal muscle protein fractional synthesis rate nor basal signalling element phosphorylation changed in response to LCn-3PUFA supplementation, but the anabolic response to insulin and amino acid infusion was greater after LCn-3PUFA [i.e. the muscle protein fractional synthesis rate during insulin and amino acid infusion increased from 0.062±0.004 to 0.083±0.007%/h and the phospho-mTOR (Ser2448) and phospho-p70S6K (Thr389) levels increased by ～50%; all P<0.05]. In addition, the muscle protein concentration and the protein/DNA ratio (i.e. muscle cell size) were both greater (P<0.05) after LCn-3PUFA supplementation. We conclude that LCn-3PUFAs have anabolic properties in healthy young and middle-aged adults.     

中老年男性脂肪肝对血清睾酮水平的影响

目的探讨中老年男性脂肪肝对血清睾酮水平的影响。方法对128例中老年男性住院患者临床资料进行回顾性分析,研究对象分为脂肪肝组(75例)和非脂肪肝组(53例),分析比较两组患者体质指数(BMI)、血清总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、空腹血糖(FBG)、空腹胰岛素(FIns)、胰岛素抵抗指数(HOMA-IR)、雌激素(E)、睾酮(T)、雌激素/睾酮(E/T)等指标。结果脂肪肝组BMI、FBG、FIns、HOMA-IR高于非脂肪肝组,差异有统计学意义(P 0.05);脂肪肝组TC、TG高于非脂肪肝组,差异有统计学意义(P 0.05),两组LDL-C、HDL-C差异无统计学意义(P 0.05);脂肪肝组睾酮水平低于非脂肪肝组(P 0.05),雌激素/睾酮高于非脂肪肝组(P 0.05),两组雌激素水平差异无统计学意义(P 0.05);睾酮与TG、FBG、FIns、HOMA-IR等指标呈负相关(P 0.05)。结论中老年男性脂肪肝患者血清睾酮水平低于非脂肪肝患者。     

Fish oil fatty acids improve postprandial vascular reactivity in healthy men

Chronic fish oil intervention had been shown to have a positive impact on endothelial function. Although high-fat meals have often been associated with a loss of postprandial vascular reactivity, studies examining the effects of fish oil fatty acids on vascular function in the postprandial phase are limited. The aim of the present study was to examine the impact of the addition of fish oil fatty acids to a standard test meal on postprandial vascular reactivity. A total of 25 men received in a random order either a placebo oil meal (40 g of mixed fat; fatty acid profile representative of the U.K. diet) or a fish oil meal (31 g of mixed fat and 9 g of fish oil) on two occasions. Vascular reactivity was measured at baseline (0 h) and 4 h after the meal by laser Doppler iontophoresis, and blood samples were taken for the measurement of plasma lipids, total nitrite, glucose and insulin. eNOS (endothelial NO synthase) and NADPH oxidase gene expression were determined in endothelial cells after incubation with TRLs (triacylglycerol-rich lipoproteins) isolated from the plasma samples taken at 4 h. Compared with baseline, sodium nitroprusside (an endothelium-independent vasodilator)-induced reactivity (P=0.024) and plasma nitrite levels (P=0.001) were increased after the fish oil meal. In endothelial cells, postprandial TRLs isolated after the fish oil meal increased eNOS and decreased NADPH oxidase gene expression compared with TRLs isolated following the placebo oil meal (P相似文献   

Serum gamma-glutamyltransferase and risk of metabolic syndrome and type 2 diabetes in middle-aged Japanese men

OBJECTIVE: To investigate the association between serum gamma-glutamyltransferase (GGT) and risk of metabolic syndrome and type 2 diabetes in Japanese male office workers. RESEARCH DESIGN AND METHODS: This study included 2,957 metabolic syndrome-free men and 3,260 nondiabetic men aged 35-59 years who did not have medication for hepatitis, alanine aminotransferase (ALT) levels higher than three times the upper limit of the reference range, or a history of cardiovascular disease at study entry. Subjects were reexamined at periodic annual health examinations over a 7-year period. We used a modified National Cholesterol Education Program definition of metabolic syndrome with BMI instead of waist circumference and the revised criteria of the American Diabetes Association for type 2 diabetes. RESULTS: With adjustment for age, family history of diabetes, BMI, alcohol intake, cigarette smoking, regular physical activity (fasting plasma glucose for the risk of type 2 diabetes), and white blood cell (WBC) count, the risk of metabolic syndrome and type 2 diabetes increased in correlation with the levels of serum GGT, ALT, aspartate aminotransferase (AST), and alkaline phosphatase. Additional adjustment for all of the other liver enzymes attenuated these associations, but serum GGT remained a significant risk factor for the risk of both metabolic syndrome and type 2 diabetes (P for trend <0.001 for both). Top one-fifth versus bottom one-fifth relative risks of metabolic syndrome and type 2 diabetes were 2.23 (95% CI 1.51-3.30) and 2.44 (1.34-4.46), respectively. CONCLUSIONS: These results indicate that serum GGT may be an important predictor for developing metabolic syndrome and type 2 diabetes in middle-aged Japanese men.     

Acute haemodynamic effects of lipolysis-induced increase of free fatty acids in healthy men

Circulating free fatty acids (FFA) are elevated in subjects with insulin resistance and Type II diabetes, and increase during myocardial ischaemia, but their haemodynamic effects are incompletely understood. During an investigation of the effects of FFA on endothelial function, we administered lipid emulsion (150 mg x min(-1) of soybean oil) with heparin (0.2 unit x kg(-1) x min(-1)) intravenously to eight healthy men for 2 h. This increased circulating FFA to 3.1+/-0.5 mmol/l. Forearm blood flow was measured by venous occlusion plethysmography during brachial artery infusions of saline, acetylcholine and nitroprusside before, and at 1 and 2 h. Lipid/heparin infusion had no significant effect on vasodilation to nitroprusside but progressively increased responses to acetylcholine (from 6.3+/-2.0 during 30 microg x min(-1) before-lipid infusion to 7.9+/-1.3 at 1 h and 12.2+/-1.1 ml x min(-1) x 100 ml(-1) at 2 h, P<0.001). Basal flow increased from 2.7+/-0.7 to 4.7+/-0.8 ml x min(-1) x 100 ml(-1) from 0 to 2 h. We performed a second study to clarify this effect on basal blood flow. Healthy men (n=8) received, on separate occasions, 4 h intravenous infusions of lipid emulsion with heparin and, as a control, saline with heparin. Lipid with heparin increased mean arterial blood pressure (maximum increment 8.2+/-2.7 mm Hg, P<0.01 compared with saline/heparin control) and forearm blood flow (from 1.7+/-0.2 to 2.9+/-0.3 ml x min(-1) x 100 ml(-1), P<0.01) without a significant effect on heart rate, and reduced calculated forearm vascular resistance (from 49.1+/-5.4 to 31.3+/-3.9 arbitrary units, P<0.01). In conclusion, acute elevation of FFA in healthy men increases arterial blood pressure and reduces vascular resistance. These haemodynamic changes could be clinically relevant.     

老年2型糖尿病患者血清抵抗素、游离脂肪酸水平研究

目的探讨血清抵抗素、游离脂肪酸与老年糖尿病及胰岛素抵抗的关系。方法测量老年(年龄>60岁)2型糖尿病患者82例(老年糖尿病组),成年(年龄<60岁)2型糖尿病患者70例(成年糖尿病组),老年健康体检者50例(对照组)空腹血清抵抗素、游离脂肪酸、空腹血糖及胰岛素水平,计算胰岛素抵抗指数。结果老年糖尿病组血清抵抗素、游离脂肪酸水平高于对照组与成年糖尿病组(P<0.05或P<0.01)。老年糖尿病组胰岛素抵抗程度较成年糖尿病组明显,并伴有脂代谢紊乱。结论血清抵抗素、游离脂肪酸与老年糖尿病尤其是老年胰岛素抵抗密切相关。     

Smoking cessation improves insulin sensitivity in healthy middle-aged men

Cigarette smokers have recently been shown to exhibit insulin resistance, dyslipidaemia and markers of the insulin resistance syndrome (IRS). The aim of this study was to examine the effects of smoking cessation on insulin sensitivity and IRS. Forty male, non-obese healthy smokers participated in this open parallel study with 8 weeks of follow-up. Seventeen subjects were able to stop smoking, while 23 subjects continued to smoke and served as a controls group. Anthropometric and metabolic data were measured. Degree of insulin sensitivity was determined with the euglycaemic hyperinsulinaemic clamp technique. Smoking cessation increased insulin sensitivity and improved the lipoprotein profile in spite of a modest increase in body weight. Initial smoking habits correlated positively with the increase in BMI as well as the improvements in the metabolic variables after smoking cessation. These data support the view that smoking causes insulin resistance and IRS, and also demonstrate that the beneficial metabolic effects of smoking cessation override the effects of an accompanying modest increase in body weight.     

Dietary saturated fatty acids increase cholesterol synthesis and fecal steroid excretion in healthy men and women

Abstract. In a strictly controlled 6-week trial with 47 healthy volunteers we have determined the effect of replacement of polyunsaturated by saturated fatty acids on the fecal steroid excretion and on the rate of whole body cholesterol synthesis, as measured both by the sterol balance method and by the concentration of the cholesterol precursor lathosterol in serum. Subjects were fed mixed natural diets, of which the total fat content was kept constant at 45% energy. Consumption of polyunsaturated fatty acids, mainly linoleic acid, was 21 % energy for the first 3-week period (P: S ratio 1.9), and 5% of energy (P: S ratio 0.2) for the next 3-week period, or vice versa. Cholesterol intake as determined by analysis of duplicate diets was 41 mg MJ^-1 (about 500 mg day^-1) during both periods. Feces were collected for 5 days at the end of both periods. The steroid composition of the feces was not affected by the change of diets. The fecal excretion of neutral steroids was significantly higher on the low P: S high-saturated-fat (2.25 ± 0.68 mmol day-¹) than on the high P:S high-linoleic-acid diet (2.00 ± 0.69 mmol day-¹; P < 0.01). The excretion of bile acids was similar (0.77 ± 0.40 and 0.79 ± 0.41 mmol day^-1, respectively). The cholesterol balance and the rate of cholesterol synthesis were higher during the low P:S (1.86 ± 0.83 mmol day^-1) than during the high P:S period (1.55 ± 0.85 mmol day^-1; P < 0.01). The ratio of lathosterol to cholesterol in serum was 0.86 ± 0.33 μmol mmol^-1 on the high-and 1.07 ± 0.39 μmol mmol^-1 on the low P: S diet (P < 0.01). Thus, both the balance and the cholesterol precursor method suggested that saturated fatty acids stimulate whole-body cholesterol synthesis.     

Serum bile acids

Summary Serum bile acid measurements now available by radioimmunoassay have proven to be the most sensitive procedure developed to assess diseases of the hepatobiliary system in both adult and pediatric liver disease. Their clinical utility appears to hold particular promise in SGOT, alkaline phosphatase, bilirubin and albumin are still normal. Serum bile acid determinations have been shown to be particularly useful in the diagnosis of alcoholic liver disease, drug-induced liver disease, viral hepatitis and cholestasis of intra- and extrahepatic origin. In infants, serum bile acid measurements can be used to establish the diagnosis of biliary atresia. When serum bile acids are determined post-prandially, they are the most sensitive indicator of liver dysfunction developed to date.