Central nervous system control of food intake and body weight

The capacity to adjust food intake in response to changing energy requirements is essential for survival. Recent progress has provided an insight into the molecular, cellular and behavioural mechanisms that link changes of body fat stores to adaptive adjustments of feeding behaviour. The physiological importance of this homeostatic control system is highlighted by the severe obesity that results from dysfunction of any of several of its key components. This new information provides a biological context within which to consider the global obesity epidemic and identifies numerous potential avenues for therapeutic intervention and future research.     

PYY modulation of cortical and hypothalamic brain areas predicts feeding behaviour in humans

The ability to maintain adequate nutrient intake is critical for survival. Complex interrelated neuronal circuits have developed in the mammalian brain to regulate many aspects of feeding behaviour, from food-seeking to meal termination. The hypothalamus and brainstem are thought to be the principal homeostatic brain areas responsible for regulating body weight. However, in the current 'obesogenic' human environment food intake is largely determined by non-homeostatic factors including cognition, emotion and reward, which are primarily processed in corticolimbic and higher cortical brain regions. Although the pleasure of eating is modulated by satiety and food deprivation increases the reward value of food, there is currently no adequate neurobiological account of this interaction between homeostatic and higher centres in the regulation of food intake in humans. Here we show, using functional magnetic resonance imaging, that peptide YY3-36 (PYY), a physiological gut-derived satiety signal, modulates neural activity within both corticolimbic and higher-cortical areas as well as homeostatic brain regions. Under conditions of high plasma PYY concentrations, mimicking the fed state, changes in neural activity within the caudolateral orbital frontal cortex predict feeding behaviour independently of meal-related sensory experiences. In contrast, in conditions of low levels of PYY, hypothalamic activation predicts food intake. Thus, the presence of a postprandial satiety factor switches food intake regulation from a homeostatic to a hedonic, corticolimbic area. Our studies give insights into the neural networks in humans that respond to a specific satiety signal to regulate food intake. An increased understanding of how such homeostatic and higher brain functions are integrated may pave the way for the development of new treatment strategies for obesity.     

Obesity as a medical problem

Obesity is now so common within the world's population that it is beginning to replace undernutrition and infectious diseases as the most significant contributor to ill health. In particular, obesity is associated with diabetes mellitus, coronary heart disease, certain forms of cancer, and sleep-breathing disorders. Obesity is defined by a body-mass index (weight divided by square of the height) of 30 kg m(-2) or greater, but this does not take into account the morbidity and mortality associated with more modest degrees of overweight, nor the detrimental effect of intra-abdominal fat. The global epidemic of obesity results from a combination of genetic susceptibility, increased availability of high-energy foods and decreased requirement for physical activity in modern society. Obesity should no longer be regarded simply as a cosmetic problem affecting certain individuals, but an epidemic that threatens global well being.     

Mechanisms linking obesity with cardiovascular disease

Obesity increases the risk of cardiovascular disease and premature death. Adipose tissue releases a large number of bioactive mediators that influence not only body weight homeostasis but also insulin resistance - the core feature of type 2 diabetes - as well as alterations in lipids, blood pressure, coagulation, fibrinolysis and inflammation, leading to endothelial dysfunction and atherosclerosis. We are now beginning to understand the underlying mechanisms as well as the ways in which smoking and dyslipidaemia increase, and physical activity attenuates, the adverse effects of obesity on cardiovascular health.     

初中生身高、BMI与身体自我满意度的关系

目的:探讨初中生身高、BMI等客观身体指标的现状、特点以及它们与身体自我的关系.方法:用黄希庭编制的身体自我量表测试615名初中生,同时测量其身高、体重.结果:男生的超重、肥胖检出率、身高、体重满意度及身体自我各维度均显著高于女生;初中生身高与身高满意度、运动特征、身材特征得分正相关(P0.01),高矮两组学生身高满意度、运动特征、身材特征均值差异显著(P0.01);初中生BMI与体重满意度、身材特征负相关(P0.01),正常、超重、肥胖3组学生体重满意度、运动、身材特征差异显著(P0.05).结论:身高、BMI影响初中生身体自我,因此,加强健康教育与体育锻炼,有助于提高初中生的身体自我意识,进而健全初中生的人格.     

不同体重指数与大学生体质健康指标表现差异的研究

为探讨不同的体重指数与大学生各项体质健康指标的关系,以4802名大学生为研究对象,分别实施各项体质健康测验.依其体重指数将学生分为低体重、正常体重、超重及肥胖四组,以体重指数为自变量,其他体质健康指标为因变量,进行单因素方差分析,并进行均数的多重比较。结果显示:体质健康指标在不同的体重指数之间的变化趋势各不相同;正常体重学生心血管功能、呼吸机能、手臂力量、下肢爆发力均优于低体重组(除呼吸机能外)、超重、肥胖组学生;低体重(除呼吸机能外)、超重、肥胖对学生身体机能、素质均产生负面影响。     

Dynamics of fat cell turnover in humans

Obesity is increasing in an epidemic manner in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells (adipocytes) is thought to be most important. Here we show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fat cells stays constant in adulthood in lean and obese individuals, even after marked weight loss, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analysing the integration of 14C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in early onset obesity, suggesting a tight regulation of fat cell number in this condition during adulthood. The high turnover of adipocytes establishes a new therapeutic target for pharmacological intervention in obesity.     

高山姬鼠瘦素抵抗模式的初步研究

为探究高山姬鼠在长期充足摄食条件下是否存在瘦素抵抗,在实验室条件下选取15只健康雄性高山姬鼠进行实验,体重为32.98±0.96g,喂以充足的小鼠标准饲料.在(25±1)℃(光照12L:12 D)条件下驯化3个月,测定其体重、摄入能、脂肪重量、血清瘦素含量.结果显示,8只高山姬鼠的体重维持稳定(正常组),为(33.94±0.83)g;而另7只高山姬鼠体重显著增加(肥胖组),为(50.58±2.00)g.肥胖组体重、摄入能及血清瘦素含量极显著高于正常组,脂肪重量肥胖组显著高于正常组.分析知,高山姬鼠的血清瘦素含量与体重、脂肪重量和摄入能呈极显著正相关.以上结果表明,高山姬鼠可能存在瘦素抵抗.     

用皮褶厚度、体脂率评价江淮汉族肥胖标准初探

为了探讨用皮褶厚度、体脂率法评价江淮地区汉族肥胖的标准,于2010年在安徽滁州和江苏淮安调查了1 426例(城市男性309例,乡村男性414例,城市女性312例,乡村女性391例)江淮汉族成年人的身高、体重、肱三头肌皮褶、肩胛下皮褶,通过身高、体重来计算身体质量指数(BMI),通过肱三头肌皮褶、肩胛下皮褶来计算体密度,采用Brozek公式计算体脂率.用BMI、皮褶厚度、体脂率分别评价江淮汉族成年人的肥胖率.结果表明:(1)江淮汉族男性BMI值为(24.1±3.6)kg/m2,女性BMI值为(23.8±3.6)kg/m2.用BMI法判断,江淮汉族超重率男性为34.7%,女性为30.7%;肥胖率男性为14.4%,女性为13.2%.(2)随年龄增长,肱三头肌皮褶、肩胛下皮褶值、BMI、体脂率增大,身高下降.(3)用长岭晋吉皮褶厚度法判断,江淮汉族肥胖率男性为39.8%,女性为30.4%.皮褶厚度法得出的肥胖率远远高于BMI法,两种方法存在较大矛盾.本研究认为用肱三头肌皮褶与肩胛下皮褶之和来判断中国人群肥胖的标准,男性应该在35~45 mm之间,女性应该在45~55 mm之间选取.(4)用长岭晋吉体脂率法作为判断肥胖的标准,肥胖率男性为43.3%,女性为5.3%.用体脂率和BMI法判断江淮汉族成年人的肥胖存在较大矛盾.长岭晋吉体脂率法男性标准定得太低;女性标准定得太高.本研究认为用体脂率来判断江淮地区汉族肥胖,男性以大于24%、女性以大于28%为宜.     

双能X线吸收测量法（DEXA）测定成年人单纯性肥胖症脂肪含量研究

 为研究肥胖症定量诊断分析与价值,应用双能X线吸收测量法(DEXA)对120例肥胖者及对照组80例正常体质量者进行全身脂肪含量测定,研究不同年龄段、性别的肥胖症患者及正常体质量人体内脂肪含量及分布规律,探讨肥胖症患者及正常体质量者DEXA的诊断指标。结果显示利用DEXA测定脂肪含量与体质量指数法（BMI）关系比较,男性相关系数r＝0.871（P<0.001）,表明两种评价方法的一致性较好;女性相关系数r＝0.521（P<0.001）,两种评价方法的一致性一般;诊断单纯性肥胖最佳“切点”男性为19.45%,女性为34.00%。故DEXA测量人体内全身的脂肪含量可进行诊断肥胖症及定量分析。     

2000-2005年福建省3城市成年人体质指数的动态分析

采用体质测量法,观察福建省3城市成年人体质指数(BMI)的动态变化,为卫生研究和政策制订提供依据.结果显示,从2000-2005年BMI<18.5的人数百分比呈下降趋势,超重肥胖的人数百分比呈增加的趋势,其中男性、三明地区和农民肥胖百分率增加最多.     

长期应用重组人睫状神经因子(rhCNTF)对谷氨酸钠肥胖大鼠血脂的影响

目的研究长期应用rhCNTF对谷氨酸钠(MSG)肥胖大鼠血脂的影响。方法建立MSG肥胖大鼠模型。3月龄时将肥胖动物随机分5组:分别皮下注射rhCNTF300μg·kg-1·d-1(高剂量组)、100μg·kg-1·d-1(中剂量组)、30μg·kg-1·d-1(低剂量组);西布曲明灌胃8 mg·kg-1·d-1(阳性对照组);模型组和对照组均给予生理盐水1 mL·kg-1·d-1,连续给药33 d。末次给药后24 h,同时动物禁食过夜后,在水合氯醛麻醉下测体重、身长,计算LI;断头后取腹部脂肪称重计算脂肪系数;腹主动脉取血离心后测血清总胆固醇、甘油三酯、高密度脂蛋白、血糖和血清胰岛素水平。结果(1)造模:正常大鼠189.40±38.72 g,谷氨酸钠肥胖大鼠平均体重(246.72±36.67)g,(P<0.001);LI(Lee’s指数)分别为289.27±9.05和304.42±9.64(P<0.001),说明造模成功。(2)药物实验结果高、中剂量给药组LI、脂肪系数、血总胆固醇、甘油三酯、血糖明显下降,高剂量组胰岛素水平也有所下降,达到统计学要求的显著性。结论rhCNTF30～300μg·kg-1·d-1皮下注射连续用药33 d,对谷氨酸钠肥胖大鼠具有明显的降脂作用,可能对Ⅱ型糖尿病肥胖有效。     

高负荷无氧运动训练对肥胖人群自由基代谢的影响

为研究高负荷无氧运动训练对肥胖人群自由基代谢的影响,按照肥胖标准选择某高职院校肥胖学生80名,随机将其划分成高负荷无氧运动训练组和对照组,对照组在实验期间不进行任何形式的运动,高负荷无氧运动训练组通过Monark功率自行车进行急性高负荷无氧运动训练。实验发现,高负荷无氧运动训练能够有效降低肥胖人群的体重等,帮助改善肥胖人群的身体形态,同时促使肥胖人群MDA含量增加,但无统计学意义,SOD、GSH-PX、T-AOC活力显著增加,由此说明肥胖人群在短暂缺氧的情况下能够增强清除自由基的能力和快速应激能力。     

Rapid development of tolerance to the behavioural actions of cholecystokinin

Cholecystokinin (CCK) acts acutely to inhibit food consumption in fasted rats, mice, sheep, pigs, monkeys and humans. CCK has been proposed as a satiety signal, inducing the behavioural sequence of satiety, or as an aversive internal stimulus, which inhibits food intake by inducing malaise. Reductions in food intake and related exploratory behaviours are initiated by CCK at its peripheral receptor in the gut, which appears to transmit sensory feedback via the vagus nerve to brain regions mediating appetitive behaviours. The therapeutic potential of CCK as an appetite suppressant in obesity syndromes rests on the demonstration of significant, long-lasting body weight reduction. Chronic CCK administration by repeated injections is problematic, since this peptide is rapidly degraded in vivo. We chose the Alzet constant infusion osmotic minipump to investigate possible alterations in body weight and food intake during continuous infusion of CCK. We now report that no change was detected in either body weight or total daily food consumption at any time point during 2 weeks of intraperitoneally (i.p.) infused CCK. The mechanism underlying the lack of chronic CCK effects appears to be a rapid development of behavioural tolerance. Acute challenge doses of CCK which induced satiety-related behaviours in saline-infused rats were ineffective in CCK-infused rats. The behavioural tolerance was apparent within a few hours of minipump implantation. These results provide the first evidence that rapid and reversible tolerance develops to the actions of a gut peptide.     

超重和肥胖与脂肪肝的相关性分析

目的：调查拉萨市墨竹工卡县不同人群脂肪肝的患病率,分析脂肪肝与体质指数、性别、职业之间的关系。方法：对随机抽样的247名干部和365名农牧民测量的身高、体重、腹部B超检查结果进行统计分析。结果：墨竹工卡县脂肪肝的患病率为15.4%;脂肪肝组的超重和肥胖检出率为74.5%,明显高于非脂肪肝组的27.8%;男、女性脂肪肝患病率无差异;不同各职业间患病率有显著差异。结论：脂肪肝的发病与超重和肥胖密切相关,控制体重是降低人群脂肪肝患病率的重要措施。     

体力活动视角下建成环境对成年人健康的影响研究

肥胖率上升给公共健康带来严峻威胁,有效的体力活动能够降低肥胖、高血压、心脑血管疾病等慢性病的发病率,是增进人群健康的重要途径;提高居民体力活动水平已经成为世界众多国家面临的严峻挑战。建成环境是城市规划建设在空间上的反映,是影响居民体力活动和健康的重要载体,已有的研究表明,建成环境会对体力活动和肥胖情况产生重要影响;以重庆市主城区为例,选择成年上班群体为研究对象,假设建成环境变量会影响其交通体力活动和休闲体力活动,进而影响其肥胖程度;研究结果表明:通勤距离、公共交通站点距居住地(工作地)的距离、最近体力活动场所距居住地(工作地)的距离、一周内去休闲体力活动场所的次数等建成环境变量与成年上班群体身体质量指数(BMI)之间存在显著联系;提出了强化成年上班群体体力活动,减少肥胖发生的建成环境优化建议。     

不同年龄人群减肥运动处方的制定

随着人们物质生活水平的提高，肥胖症日益增多，严重威胁着人类的健康。然而经过实践证明：透彻地认识减肥机理，科学地制定运动处方才是防治肥胖症的最佳疗法。     

Inflammation and metabolic disorders

Metabolic and immune systems are among the most fundamental requirements for survival. Many metabolic and immune response pathways or nutrient- and pathogen-sensing systems have been evolutionarily conserved throughout species. As a result, immune response and metabolic regulation are highly integrated and the proper function of each is dependent on the other. This interface can be viewed as a central homeostatic mechanism, dysfunction of which can lead to a cluster of chronic metabolic disorders, particularly obesity, type 2 diabetes and cardiovascular disease. Collectively, these diseases constitute the greatest current threat to global human health and welfare.     

高校体育与健康教育对提高大学生体质健康水平的影响

为探讨高校体育与健康教育对大学生体质健康水平的渐进影响,以河北科技师范学院2006级4 879名在校大学生为研究对象,对其进行三学年体质健康测试、体育意识与行为问卷调查、体育健康知识与健康体育行为问卷跟踪调查。结果显示:大学生第一至第三学年体质健康水平呈逐渐提高趋势,而不及格比率随年级升高而增加。经数据统计显示,大部分体测不及格是由于其身体形态测试结果不合格所至,男生肥胖比例较高;大学生体育意识显著提高,但体育行为的提高速率显著慢于体育意识的增长速率,体育健康知识的掌握情况不容乐观,但大学生体育健康行为情况好于体育健康知识的掌握情况。     

从体脂肪含量看湖北省中小学学生的肥胖现状

肥胖已成为威胁中小学学生健康的重要因素之一,为预防中小学学生肥胖提供参考.用测量法及数理统计方法研究的结果是:肥胖男生的形态发育状况良好,其体重、体脂重和瘦体重均显著高于正常学生;肥胖女生的形态发育并不显著好于正常女生,其体重较大主要是体内的脂肪含量较多而并非瘦体重较大造成的;肥胖男、女学生的身体机能状况均较正常学生差,且这种差异,男生在高中阶段、女生则从初中阶段开始就已有显著性.要预防中小学学生肥胖,应特别注意那些形态发育较好的男生及在青春期体重及体脂肪含量迅速增加的女生.