Modification with homocysteine does not increase susceptibility of human low-density lipoprotein to iron-mediated oxidation

Oxidation of human low-density lipoprotein (LDL) is centrally involved in the development of cardiovascular diseases. This study investigated whether homocysteine-mediated thiolation of LDL rendered it more susceptible to oxidation by iron. After in vitro exposure to homocysteine thiolactone for 60 minutes, LDL's thiol content increased from 26 ± 5 (control) to 224 ± 20 nmol/mg of protein (thiolated; P < .0001). Control and thiolated LDL (0.2 mg of protein per milliliter) were incubated with either redox active iron (Fe³⁺; 10 μmol/L) or, as a positive control, copper (Cu²⁺; 10 μmol/L). Consistent with the observation of others, thiolation decreased Cu²⁺-dependent formation of lipid oxidation products in LDL (17 ± 16 nmol/mg of protein formed in thiolated LDL, compared with 81 ± 21 nmol/mg of protein in control, during 6 hours of incubation; P < .01). Thiolation had no effect, however, on Fe³⁺-mediated oxidation of LDL with lipid oxidation products remaining essentially nondetectable during prolonged incubation (up to 48 hours). Thiolation similarly had no effect on oxidation of LDL (0.2 mg of protein per milliliter) by heme-complexed iron (hemin; 10 μmol/L), with lipid oxidation products increasing to 24 ± 1 and 27 ± 4 nmol/mg of protein for control and thiolated LDL, respectively, during 6 hours of incubation (P > .05). Similar results were observed using LDL with varying degrees of thiolation (29 ± 5, 85 ± 14, 130 ± 15, and 213 ± 19 nmol of thiol per milligram of protein). In conclusion, these results demonstrate that thiolation has no effect on LDL's susceptibility to iron-mediated oxidation.     

Long-term fructose-enriched diet introduced immediately after weaning does not induce oxidative stress in the rat liver

Increased fructose consumption is correlated with the rising prevalence of obesity, metabolic syndrome, and type 2 diabetes. It is believed that reactive oxygen species contribute to the development and progression of metabolic disturbances, especially those associated with insulin resistance. Dietary fructose produces both pro-oxidative and antioxidative effects, depending upon the experimental conditions, dosage, duration of treatment, and pathophysiological milieu. The effects of fructose overconsumption on young populations, which have an increased risk of developing metabolic disorders in adulthood, have not been fully elucidated. We have previously shown that rats subjected to a long-term fructose-enriched diet immediately after weaning display impaired hepatic insulin sensitivity. In this study, we tested the hypothesis that long-term fructose consumption induces alterations in the redox setting of the liver. Starting from the 21st day after birth, male Wistar rats were maintained for 9 weeks on a standard diet (control) or a fructose-enriched diet that consisted of standard food and 10% fructose solution instead of drinking water. The expression and activity of antioxidant enzymes as well as lipid peroxidation and protein damage markers were measured. The results showed that a fructose-enriched diet led to an increased expression of mitochondrial manganese superoxide dismutase but did not affect antioxidant enzymes activity, lipid peroxidation, thiol content, and the level of protein oxidation. Therefore, our results suggest that the decrease in hepatic insulin sensitivity that was previously observed in rats that were kept on the same diet regime might be attributed to molecular mechanisms other than redox disbalance. A possible fructose-related micronutrient deficiency should be examined.     

Development and application of rapid assessment diet and physical activity indexes,which suggest high consumption of energy-dense foods and inadequate exercise among adolescents from 6 Latin American cities: a pilot study

This study describes the development and application of a rapid assessment diet quality index (RADQI) and a rapid assessment physical activity index (RAPAI) to characterize the energy intake and expenditure patterns of 1279 Latin American adolescents. Secondary aims were to describe the strength of the relationships of energy intakes and expenditures with sex, socioeconomic status, body mass index, and city of residence and to identify the students' reasons for undertaking physical activity and the types of activities they most enjoyed. Participants were eighth and ninth grade students from Buenos Aires, Argentina; Guatemala City, Guatemala; Havana, Cuba; Lima, Peru; Panama City, Panama; and Santiago, Chile. The RADQI and RAPAI scores were rescaled to T scores with a mean of 50 points (±10) for comparison. The RADQI scores ranged from 53.0 points (±10.5) in Panama City to 44.7 points (±8.3) in Santiago, and RAPAI scores ranged from 54.8 points (±9.2) in Panama City to 46.2 points (±8.6) in Santiago. The correlation between RADQI and RAPAI scores for the combined data set was weak but positive. The 2 reasons most often given for undertaking physical activity were to improve their physical health and to improve their psychological well-being, whereas the types of physical activities most enjoyed involved competitive sports. Results suggest frequent intakes of energy-dense diets and inadequate physical activity participation, prompting a need for learning opportunities targeted at adolescents and their families that teach healthy food choices and encourage greater physical activity participation.     

代谢综合征的患病机制及其防治

代谢综合征(MS)是以中心性肥胖、胰岛素抵抗(IR)、高血压、高脂血症、低高密度脂蛋白胆固醇(HDL-C)、糖耐量减低(IGT)或2型糖尿病(T2DM)为主要特征的综合征.防治MS的主要目标是防止或延缓心血管疾病(CVD)及T2DM的发生和发展.积极地改善生活方式是防治MS的首要和基础措施.对于生活方式干预后效果不显著和处在CVD高危状态的个体,应对代谢异常进行相应的药物治疗.     

Long-term intake of rice improves insulin sensitivity in mice fed a high-fat diet

ObjectiveThe aim of this study was to evaluate the effects of rice as a carbohydrate source and its molecular mechanisms on insulin resistance induced by a high-fat diet (HFD).MethodsC57 BL/6 J mice were divided into three groups and were fed a low-fat diet (LFD); a HFD (with 18% fat, 0.5% cholesterol, 51.5% w/w cornstarch and sucrose); or a HFD with rice (HFD-CR, with 18% fat, 0.5% cholesterol and 51.5% w/w rice powder) for 12 wk. In the HFD-CR diet, cooked rice powder was substituted for cornstarch and sucrose in the HFD as a carbohydrate source.ResultsHFD-CR–fed mice had significantly lower body weight, blood glucose, insulin and leptin levels and ameliorated glucose responses with decreased homeostasis model assessment-insulin resistance compared with HFD-fed mice. Hepatic mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase were down-regulated in the HFD-CR group. The hypertrophied islet size and the decreased pancreatic mRNA expression of glucose transporter 2 in the HFD group were normalized with cooked rice consumption. Rice promoted glucose uptake by activating AMP-activated protein kinase and downstream glucose transporter 4 in the skeletal muscle.ConclusionRice consumption as a carbohydrate source might potentiate improvements in glucose uptake via AMP-activated protein kinase activation and glucose transporter 4 expression in the skeletal muscles, thereby improving insulin sensitivity.     

某社区饮食干预对代谢综合征患者饮食的影响

[目的 ]　探讨社区饮食干预对代谢综合征患者饮食行为的影响。　 [方法 ]　随机挑选 13 2例代谢综合征患者 ,对其中 66例进行为期 3个月的饮食干预 ,干预方法采用食品交换法 ,另外 66例患者作为对照。　 [结果 ]　干预 3个月后 ,干预组患者每日摄入的总能量、碳水化合物和脂肪的量以及脂肪产生能量占总能量的百分比均有显著降低 ,且明显低于对照组。　 [结论 ]　社区饮食干预能有效改善代谢综合征患者的饮食行为。     

The metabolic and neuroinflammatory changes induced by consuming a cafeteria diet are age-dependent

Objectives: To compare the effects of a palatable cafeteria diet on serum parameters and neuroinflammatory markers of young and aged female Wistar rats.

Methods: Three-month-old (young) and 18-month-old (aged) female Wistar rats had access to a cafeteria diet (Caf-Young, Caf-Aged) or a standard chow diet (Std-Young, Std-Aged).

Results: The Caf-Young group showed a higher food consumption, weight gain, visceral fat depot, serum insulin and leptin levels, and the insulin resistance index (HOMA-IR) than the Std-Young group. The Caf-Aged group exhibited an increase in interleukin-1 levels in the cerebral cortex and hippocampus. The number of GFAP-positive cells did not differ between the groups, but there was a diet effect in the cerebral cortex and an age effect in the hippocampus. Phospho-tau expression did not differ between the groups.

Discussion: The 3- and 18-month-old rats responded differently to a cafeteria diet. Insulin and leptin levels are elevated in young animals fed a cafeteria diet, whereas aged animals are prone to neuroinflammation (indicated by an increase in interleukin-1β levels). A combination of hypercaloric diet and senescence have detrimental effects on the inflammatory response in the brain, which may predispose to neurological diseases.     

大气PM_(2.5)长期暴露对健康影响的队列研究进展

大气PM_(2.5)污染是危害人类健康的重要因素,已经成为全球热点问题。长期暴露于大气PM_(2.5)污染与疾病的发生和死亡密切相关,特别是心血管疾病和呼吸系统疾病,但不同研究的结论并不一致。基于人群的队列研究是评价大气污染慢性效应的重要方法。该文从暴露估计方法、健康效应评估两方面综述了大气PM_(2.5)长期暴露对健康影响的队列研究进展,指出了现有研究存在的问题,并提出了今后开展此类研究的建议。     

Chronic consumption of a moderately low protein diet does not alter hematopoietic processes in young adult mice

The current studies examined whether hematopoiesis in the bone marrow and T-cell development in the thymus were attenuated in young adult A/J mice fed a moderately low protein diet (MPD, 50 g protein/kg) for 15 wk compared with mice fed a control protein diet (CPD, 180 g protein/kg). Flow cytometric analyses using antibodies against CD31 and Ly-6C as well as CD4 and CD8 were performed to identify stem, mixed progenitor, erythroid, lymphoid, granuloid and monocytic compartments in the bone marrow and four thymocyte subsets, respectively. Chronic restriction of young adult mice to MPD neither decreased the cellularity nor altered the distribution of subpopulations in either primary tissue. Subsequently, a new set of mice were provided with CPD and a low protein diet (LPD, 25 g protein/kg). After 5 wk, body and thymus weights in LPD group were reduced 26 and 30%, respectively, which was accompanied by a 505% increase in serum corticosterone. Surprisingly, LPD did not alter the number or distribution of cells in the bone marrow and the percentages of thymocyte subsets, supporting the findings from the MPD group. We conclude that chronic consumption of a marginal protein diet by young adult mice does not disrupt hematopoietic processes.     

Repeated applications of cold atmospheric pressure plasma does not induce resistance in Staphylococcus aureus embedded in biofilms

Introduction: The increasing microbial resistance against antibiotics complicates the therapy of bacterial infections. Therefore new therapeutic options, particularly those causing no resistance, are of high interest. Cold atmospheric plasma is one possible option to eradicate multidrug resistant microorganisms, and so far no resistance development against physical plasma is known.Method: We tested 6-fold repeated plasma applications on a Staphylococcus aureus strain embedded in biofilm and compared the reduction of the colony forming units between the different treatment periods to asses a possible development of resistance.Result: For all treatment periods, the control biofilms were reduced by plasma in average by 1.7 log₁₀ CFU, and decreased from 7.6 to 5.8 log₁₀ (CFU/cm²) within 5 hours. The results demonstrated that repeated plasma doses not induce resistance or habituation against plasma applied within short time periods.Conclusion: The repeated application of cold plasma is a promising option for the treatment of infected wounds without the risk of development of resistance against plasma.     

Psychological benefits of a high-protein, low-carbohydrate diet in obese women with polycystic ovary syndrome--a pilot study

This study compared the psychological effects of a low-protein high-carbohydrate (LPHC) diet and a high-protein low-carbohydrate (HPLC) diet in women with polycystic ovary syndrome (PCOS). Twenty-five overweight women with PCOS were matched for age, weight, and whether they were trying to conceive. They were randomly allocated to the LPHC or HPLC diet for 16 weeks. All participants attended a weekly exercise, group support and educational program. The Hospital Anxiety and Depression Scale and the Rosenberg Self Esteem Scale were administered at the beginning and end of the study. The HPLC diet was associated with significant reduction in depression and improvement in self-esteem. There was no change in any psychological measures for the LPHC group. There was no difference in weight loss between the groups. Due to enhanced feelings of well-being, it is possible that HPLC diets may be associated with better compliance and hence be more successful in the long term treatment of obesity.     

Maternal hypertriglyceridemia during late pregnancy does not affect the increase in circulating triglycerides caused by the long-term consumption of a sucrose-rich diet by rats

Feeding a sucrose-rich diet (SRD) during pregnancy enhances maternal hypertriglyceridemia. The goal of this study was to investigate whether this effect is modified when pregnancy is initiated in rats at different times during feeding of a SRD (63 g sucrose/100 g). One group of rats was fed the SRD; another group received the same diet except that the sucrose was replaced by an equal amount of cornstarch. At different times during the feeding of the diets, i.e., 5, 45 or 90 d, half of the rats were mated; after serial tail blood collections, rats were studied at d 20 of pregnancy. Virgin rats fed the same diets were always studied in parallel. Plasma triglycerides increased progressively in virgin rats fed the SRD from d 1 to 35, declined thereafter up to d 50, increased again to attain the highest level at d 65-70, partially declined at d 100 and increased again at d 110. During late pregnancy, rats fed the control diet (CD) always had greater plasma triglyceride concentrations than virgin rats, whereas triglyceride levels did not differ between pregnant and virgin rats fed the SRD. These intergroup differences were similar to those seen for plasma VLDL-triglycerides. The liver triglyceride concentration in virgin rats fed the SRD was always significantly higher than that of rats fed the CD, whereas it did not differ in pregnant rats fed the SRD for either 25 or 65 d from those fed the CD. However, in those fed the SRD for 110 d, values were higher than in either pregnant or virgin rats fed the CD. We propose that the known capability of the liver to enhance triglyceride secretion during pregnancy protects dams from developing a fatty liver when fed a SRD for short periods of time, although not for long-term treatments.     

Dietary intake of medium- and long-chain triacylglycerols ameliorates insulin resistance in rats fed a high-fat diet

Objective

Excessive accumulation of visceral fat is strongly associated with insulin resistance. The present investigation examined the effects of dietary intake of medium- and long-chain triacylglycerols (MLCTs), which have been shown to induce significantly lower visceral fat accumulation in rats and humans, on high-fat diet-induced obesity and insulin resistance in rats. These effects were then compared with those observed in long-chain triacylglycerol (LCT)-fed rats.

Methods

After an 8-wk feeding of a high-fat diet, which induced severe whole-body insulin resistance, male Sprague-Dawley rats were fed a standard diet containing LCTs or MLCTs for 6 wk. After the dietary treatment, an oral glucose tolerance test was performed.

Results

Although body weight and total intra-abdominal fat mass did not differ between the two groups, mesenteric fat weight in the MLCT-fed group was significantly lower than that in the LCT group (P < 0.05). The increase in plasma insulin concentrations, but not in glucose, after glucose administration (area under the curve) was significantly smaller in the MLCT group than in the LCT group (P < 0.01) and was significantly associated with mesenteric fat weight (P < 0.05). MLCT-fed rats had significantly higher plasma adiponectin concentrations compared with LCT rats (P < 0.05). Adiponectin concentrations were negatively correlated with the area under the curve for plasma insulin (P < 0.05) and tended to be inversely related to mesenteric fat weight (P = 0.08).

Conclusion

These results suggest that dietary intake of MLCTs may improve insulin resistance in rats fed a high-fat diet, at least in part through increased adiponectin concentrations caused by a lower mesenteric fat mass.     

Cardiorespiratory fitness is associated with features of metabolic risk factors in children. Should cardiorespiratory fitness be assessed in a European health monitoring system? The European Youth Heart Study

The question as to whether fitness should be assessed in a European health monitoring system, perhaps from the early stages of life onwards, remains to be answered. We aimed to examine the associations between cardiorespiratory fitness and metabolic risk factors in children. A total of 873 healthy children from Sweden and Estonia aged 9–10 years (444 girls and 429 boys) were randomly selected. A maximal ergometer bike test was used to estimate cardiorespiratory fitness. Additional cardiovascular risk factors were assessed. Significant differences among cardiorespiratory fitness quartiles for the sum of five skinfolds, insulin resistance, triglycerides, and total cholesterol (TC) and high-density lipoprotein cholesterol (HDLc) ratio were shown in girls whereas in boys, the sum of five skinfolds and insulin resistance were significantly different. The lowest sum of five skinfolds and insulin resistance was shown in the highest cardiorespiratory fitness quartile in girls and boys, and the lowest values of triglyceride and TC/HDLc values in the highest cardiorespiratory fitness quartile was observed only in girls. Cardiorespiratory fitness was negatively associated with a clustering of metabolic risk factors in girls and boys. The results add supportive evidence to the body of knowledge suggesting that cardiorespiratory fitness in children is an important health marker and thus should be considered to be included in a pan-European health monitoring system.     

高脂饮食构建胰岛素抵抗脂肪肝大鼠模型

目的通过高脂饮食构建非酒精性脂肪肝病（NAFLD）大鼠模型;分析胰岛素抵抗（IR）在NAFLD形成过程中的作用。方法将48只雄性SD大鼠随机分为正常饮食组（NG）及高脂饮食组（FG）各24只。第2、4、6、8周末时,2组各随机抽取6只,称体重,测空腹血糖、空腹胰岛素、甘油三酯、总胆固醇、丙氨酸氨基转移酶和天门冬氨酸氨基转移酶,并计算空腹胰岛素抵抗指数;然后计算肝指数（肝湿重（g）／体重（g）×100％）;制备肝组织匀浆测丙二醛、超氧化物歧化酶以及光镜检查肝组织切片以评价肝脏脂肪变性程度。结果FG组大鼠的体重增长比NG组快;肝指数在第2、4、6、8周末均大于NG;第2周末时已出现肝细胞脂肪变,其程度随喂养时间的延长逐渐加重,第4周末开始出现IR、高TG、TC血症、肝脏转氨酶异常及肝脏脂质过氧化损害,第6周末时形成轻度脂肪肝,第8周末时发展为中度脂肪肝。结论SD大鼠用改良型高脂饲料持续喂养6周可形成伴有IR的NAFLD,IR在NAFLD的发生发展中有重要作用。     

Insulin resistance is not associated with thermogenic effect of a high-fat meal in obese children

In adults, insulin resistance may decrease the thermogenic effect of food, contributing to weight gain. We aimed to determine the effect of insulin resistance on energy expenditure in children with long-standing obesity. We hypothesized that thermogenic effect of food would decrease with increasing insulin resistance. Energy expenditure was measured using whole room indirect calorimetry in obese children 7 to 18 years old. Participants were fed a high-fat meal with energy content equal to 35% of measured resting energy expenditure. Thermogenic effect of food was measured for 180 minutes posttest meal and expressed as a percent of calories consumed. Body composition was assessed using whole-body dual-energy x-ray absorptiometry. Fasting glucose, insulin, and hemoglobin A1C were measured. Complete data were available for 25 children (median age, 12.1 years; 52% male). As expected, a significant decrease in resting energy expenditure was observed with increasing Tanner stage (P = .02 by Kruskal-Wallis test). Insulin sensitivity, as determined by homeostasis model assessment index equation, did not significantly affect resting energy expenditure (P = .3) or thermogenic effect of food (P = .7) after adjustment for Tanner stage. In conclusion, our study did not find an association between insulin resistance and energy expenditure in obese children.     

Long-term effects of non-surgical therapy for obesity on cardiovascular risk management: a weighted empirical review

Weight loss affects cardiovascular risk profiles in obese patients. Surgery is not a plausible or viable response to the public health problem of obesity, given that more than 30% of adults are obese in some countries. However, most studies investigating the effects of weight loss on the cardiovascular risk profile are focussed on weight loss and limited to short-term effects. Since newer data show a rebound of cardiovascular risks in studies that complete a short-term follow-up, the question arises whether, and to what extent, long-term treatments offer a more sustained cardiovascular benefit beside the extensive or less marked weight loss. Aims The purpose of this article is to critically review existing data on the long-term cardiovascular effects of weight loss in obese and overweight patients treated with dietary interventions, physical activity programmes, behavioural therapy and pharmacological treatments and their combination. Method Inclusion criteria were peer-reviewed, randomized controlled trials (RCT) in the English language which presented data on cardiovascular effects at a follow-up of at least 18 months during or after weight reduction interventions. The search was limited to adults and the publication years between 1990 and 2007. Studies of patients with diagnoses such as coronary heart disease and cancer, and medically treated diabetes and hypertension were excluded. Results Twenty-three studies measured cardiovascular risk factors after 18 months or more. Mean BMI was 33.9 kg/m2 including 13,733 patients. Mean duration of the studies was 37 months with a dropout rate of 16.1% on average. Regardless of the absolute amount of weight loss a positive effect on cardiovascular risk factors such as blood pressure, lipids and glucose tolerance was found.     

The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Purpose: Observationally, homocysteine is associated with higher risk of diabetes. Folate, which reduces homocysteine, is promising for the prevention and treatment of diabetes. Previous meta-analysis of three trials suggested folate might lower hemoglobin A_1c (HbA_1c). Methods: An updated systematic review and meta-analysis of placebo-controlled randomized trials was conducted. We searched PubMed using (“folate” or “folic acid”) and trial and (“glucose” or “diabetes” or “insulin” or “hemoglobin A_1c” or “HbA_1c”) in any field until February 3, 2017. We also conducted a bibliographic search of selected studies and relevant reviews. Relative risk of diabetes and mean differences in indicators of glucose metabolism between folate and placebo were summarized in a meta-analysis using inverse variance weighting with random effects. Heterogeneity, publication bias, and risk of bias were also assessed. Results: Eighteen trials of 21,081 people with/without diabetes were identified. Folate decreased fasting glucose (?0.15 mmol/L, 95% confidence interval [CI] ?0.29 to ?0.01), homeostatic model assessment–insulin resistance (?0.83, 95% CI ?1.31 to ?0.34), and insulin (?1.94 μIU/mL, 95% CI ?3.28 to ?0.61) but had no clear effect on diabetes or HbA_1c. Conclusions: Our study suggests a potential benefit of folate on insulin resistance and glycemic control; the latter requires examination in more high-quality trials.