咖啡酸苯乙酯对肥胖小鼠氧化应激状态调节作用研究

[目的]明确肥胖发生机制,并考察咖啡酸苯乙酯(CAPE)对肥胖小鼠体内氧化应激状态的调节作用。[方法]采用营养饲料(含有高组分的糖、蛋白以及脂肪)喂养昆明系小鼠4周,建模成功后随机分组,CAPE注射组分别给予不同剂量的CAPE,继续喂养50 d,测定其体重、脂体比和肝脏比重;测量其血清中总胆固醇(TC)和甘油三酯(TG)含量,并对其肝脏氧化损伤指标:脂质过氧化反应(LPO)、蛋白羰基化(PCO)以及体内抗氧化防御系统:谷胱甘肽(GSH)和过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性进行了测定。[结果]营养饲料能够促进小鼠体重(P0.01)、体脂含量(P0.05)以及肝脏比重(P0.05)的增加,提高其血清中TC、TG水平,有利于小鼠肥胖的发生;CAPE能够缓解小鼠体重、脂体比以及肝脏比重的增加(P0.05),同时肥胖会影响小鼠体内氧化应激状态,导致其氧化损伤程度增加,且抗氧化酶活性发生变化;CAPE能够缓解体内氧化应激状态,调节体内抗氧化酶的活性。[结论]氧化应激可能参与肥胖的发生,CAPE有望通过其抗氧化作用调节体内的氧化压力起到抑制肥胖发生的作用。     

Spontaneously obese dogs exhibit greater postprandial glucose, triglyceride, and insulin concentrations than lean dogs

Dogs do not appear to progress from obesity-induced insulin resistance to type 2 diabetes mellitus. Both postprandial hyperglycemia and postprandial hypertriglyceridemia have been proposed to cause or maintain beta cell failure and progression to type 2 diabetes mellitus in other species. Postprandial glucose, triglyceride, and insulin concentrations have not been compared in lean and obese dogs. We measured serum glucose, triglyceride, and insulin concentrations in nine naturally occurring obese and nine age- and gender-matched lean dogs. After a 24-h fast, dogs were fed half their calculated daily energy requirement of a standardized diet that provided 37% and 40% of metabolizable energy as carbohydrate and fat, respectively. Fasting and postprandial glucose and triglyceride concentrations were greater in the obese dogs (P < 0.001), although the mean insulin concentration for this group was five times greater than that of the lean group (P < 0.001). Most of the 0.6 mM (11 mg/dL) difference in mean postprandial glucose concentrations between lean and obese dogs was attributable to a subset of persistently hyperglycemic obese dogs with mean postprandial glucose concentrations 1.0 mM (18 mg/dL) greater than that in lean dogs. Persistently hyperglycemic obese dogs had lower triglyceride (P = 0.02 to 0.04) and insulin (P < 0.02) concentrations than other obese dogs. None of the dogs developed clinical signs of diabetes mellitus during follow-up for a median of 2.6 yr. We conclude that pancreatic beta cells in dogs are either not sensitive to toxicity because of mild hyperglycemia or lack another component of the pathophysiology of beta cell failure in type 2 diabetes mellitus.     

Effects of weight loss in obese cats on biochemical analytes related to inflammation and glucose homeostasis

The aim of the current study was to measure circulating metabolic and inflammation-related biochemical analytes in obese cats before and after weight loss. Thirty-seven overweight neutered cats were studied, median body weight 6.85 kg (range, 4.70 to 10.30 kg), representing a range of ages and both sexes. An individualized weight-loss program was devised for each cat and monitored until completion. Body fat mass was determined by dual-energy x-ray absorptiometry, whereas plasma concentrations of acute-phase proteins (APPs; eg, haptoglobin and serum amyloid A), hormones (eg, insulin, IGF-1, and adiponectin), and enzymes (eg, butyrylcholinesterase and paraoxonase type 1 [PON-1]) associated with inflammation and metabolic compounds (eg, glucose) were also measured. No significant changes were found in APPs after weight loss (P > 0.3), but significant increases in plasma adiponectin (P = 0.021) and IGF-1 (P = 0.036) were seen, whereas insulin (P < 0.001) and homeostasis model assessment (P = 0.005) decreased significantly. Plasma concentrations before weight loss of PON-1 (P = 0.004), adiponectin (P = 0.02), and IGF-1 (P = 0.048) were less in cats that failed to complete weight loss than cats that were successful, whereas glucose concentration was greater. Finally, multivariable linear regression analysis showed that lean tissue loss during weight management was associated with percentage weight loss (greater weight loss, greater lean tissue loss; R = 0.71, P < 0.001) and plasma adiponectin concentration before weight loss (lesser adiponectin, more lean tissue loss; R = -0.52, P = 0.023). In conclusion, various metabolic abnormalities occur in feline obesity, and these can be linked to outcomes of weight-loss programs. The changes that occur with weight loss suggest an improved metabolic status.     

Improvement in insulin resistance and reduction in plasma inflammatory adipokines after weight loss in obese dogs

Obesity is now a major disease of dogs, predisposing to numerous disorders including diabetes mellitus. Adipocytes are active endocrine cells, and human obesity is characterized by derangements in inflammatory adipokine production. However, it is unclear as to whether similar changes occur in dogs. The purpose of the current study was to assess insulin sensitivity and inflammatory adipokine profiles in dogs with naturally occurring obesity and to investigate the effect of subsequent weight loss. Twenty-six overweight dogs were studied, representing a range of breeds and both sexes. All dogs underwent a weight loss program involving diet and exercise. Body fat mass was measured by dual-energy x-ray absorptiometry; plasma concentrations of insulin, glucose, and a panel of inflammatory adipokines (including acute-phase proteins, cytokines, and chemokines) were also analyzed. Body fat mass before weight loss was positively correlated with both plasma insulin concentrations (Kendall τ = 0.30, P = 0.044) and insulin:glucose ratio (Kendall τ = 0.36, P = 0.022), and both decreased after weight loss (P = 0.0037 and 0.0063, respectively). Weight loss also led to notable decreases in plasma tumor necrosis factor-α (TNF-α), haptoglobin, and C-reactive protein concentrations (P < 0.05 for all), suggesting improvement of a subclinical inflammatory state associated with obesity. This study has demonstrated that in obese dogs, insulin resistance correlates with degree of adiposity, and weight loss improves insulin sensitivity. Concurrent decreases in TNF-α and adipose tissue mass suggest that in dogs, as in humans, this adipokine may be implicated in the insulin resistance of obesity.     

Regulation of Insulin Action by Diet and Exercise

The regulation of the cellular actions of the hormone insulin is essential to the maintenance of macronutrient metabolism, body weight regulation, and a surprisingly diverse range of other integrative physiologic functions. Because of the diverse targets of insulin action, any dysfunction in insulin is likely to have systemic consequences. Although type 1 and type 2 diabetes are the most obvious clinical consequences of impaired insulin synthesis and insulin action, respectively, there are also subclinical disorders that attend defects in the function of insulin. In humans and horses, the “metabolic syndrome” is characterized by a cluster of metabolic sequelae that arise as a result of insulin resistance. Importantly, both diet and exercise can regulate insulin action and can thus be leveraged as treatment tools to prevent and treat the metabolic syndrome. The aim of this review is to characterize the integrative biology of insulin action and to describe the role of diet and exercise in regulating tissue responsiveness to insulin.     

我国流动儿童超重及肥胖的社会经济因素的相关性分析*

以城市流动儿童为研究对象，分析流动儿童超重及肥胖的影响因素。运用文献资料法、测试法和数理统计法等对四川省8所公立学校7～12岁共2431名学生从身高、体重、 BMI,并调查相应的社会经济因素等指标进行动态观察、对比和分析，结果表明：父母不同的职业对儿童的超重及肥胖情况有影响，父母职业为公务员、商业服务业人员的儿童超重及肥胖情况更严重，父母职业为农民的儿童超重及肥胖的情况较轻；父母不同的教育程度对儿童的超重及肥胖情况有影响，母亲教育程度较低的儿童超重及肥胖情况更严重；不同的家庭收入对儿童的超重及肥胖情况有影响，家庭收入较低的儿童超重及肥胖情况更严重。     

Toll-like receptors and obesity-related hypertension

With increasing accumulation of evidence, obesity-related hypertension is becoming international health problem.However, the pathogenesis and treatment of this disease are still controversial.Recently, there is a widespread concern about the relationship between Toll-like receptors(TLRs) and the pathogenesis of obesity-related hypertension.The processes from the diet to the metabolism and the possible factors such as fat factors, insulin, adiponectin and renin-angiotensin system that directly lead to obesity-related hypertension are considered to be associated with the functions of TLRs.This paper will try to find the role of TLRs in the pathogenesis of obesity-related hypertension, and provide a new and important perspective for the treatment of this type of hypertension.     

Effects of chronic obesity and weight loss on plasma ghrelin and leptin concentrations in dogs

The objective of this study was to evaluate, in dogs, the effects of obesity and weight loss on plasma total ghrelin and leptin concentrations. Twenty-four Beagle dogs, 12 control lean and 12 obese dogs of both genders and aged between 1 and 9 years, were used for the experiments. Mean body weight was 12.7+/-0.7 kg for the lean group and 21.9+/-0.8 kg for the obese group. The trial was divided into three phases. During phase 1, all 24 Beagle dogs were fed a maintenance diet. During phase 2, the obese dogs were submitted to a weight loss protocol with a high protein-low energy diet. The weight loss protocol ended once dogs reached optimal body weight. During phase 3, the dogs that were submitted to the weight loss protocol were maintained at their optimal body weight for 6 months. Plasma total ghrelin, leptin, insulin and glucose concentrations were measured to evaluate the effects of obesity and weight loss on these parameters in dogs. Body weight, body condition score, thoracic and pelvic perimeters, and ingested food amounts were also recorded during the study. Obese dogs demonstrated a significant decrease in plasma ghrelin and a significant increase in plasma leptin and insulin concentrations when compared with control dogs. During weight loss, significant increases in plasma total ghrelin and glucose and significant decreases in plasma leptin and insulin were observed. The increase in plasma ghrelin concentrations seemed to be transient. Body weight and the morphometric parameters correlated positively with leptin concentrations and negatively with total ghrelin concentrations. These results suggest that ghrelin and leptin could play a role in dogs in the adaptation to a positive or negative energy balance, as observed in humans.     

Progress in resistin and type 2 diabetes as well as obesity

Resistin, a new hormone found in the year 2001 and secreted by adipocytes, is related to type 2 diabetes and obesity. It brings some hope to solve the medical hamper of insulin resistance. The resistin discovery, molecule structure, function and expression, secretion regulation as well as gene polymorphism are reviewed in the article.