不要迷信“瘦体素”

过去几年，美国哥伦比亚大学一个团队研究了许多减肥容易而保持减肥效果困难的例子。

罗伊氏乳酸杆菌(Lactobacillus reuteri) GKD2改善高脂高糖饮食动物模式之血糖调控

葡萄糖耐受不良(impaired glucose tolerance)系指生理对血糖调控能力较差的状态,虽无明显临床症状,却为糖尿病(diabetes)或心血管疾病(cardiovascular diseases)的病变前兆。此阶段往往被忽视,或医疗建议的饮食控制与运动对于此类族群的实施效果有限。益生菌(probiotics)系指对人体机能有益的细菌,可参与人体的生理代谢、肠道菌相调整等,广受市场接受,因此具应用于糖尿病病变前期对策的潜能。本实验以高脂、高糖(high fat-high sugar, HF-HS)的饮食方式诱导C57BL/6JNarl小鼠发生葡萄糖耐受不良的状况,模拟常见之葡萄糖耐受不良成因。HF-HS小鼠分别补充8周低剂量(20.5 mg/kg/day)与高剂量(102.5 mg/kg/day)的罗伊氏乳酸杆菌(Lactobacillus reuteri) GKD2菌粉。在口服葡萄糖耐受性试验(oral glucose toerance test)中,相比单纯HF-HS饮食组,摄入菌株GKD2的HF-HS小鼠,其餐后血糖值有较低的趋势。此外,血糖调节的相关指标瘦体素(leptin)在益生菌组观察到下降的趋势;非空腹的胰岛素(insulin)浓度以高剂量GKD2组呈显著下降(p p L. reuteri GKD2有助于高脂高糖饮食者的血糖调控与生理代谢。

Leptin and peroxisome proliferator-activated receptor γ expression in colorectal adenoma

AIM： To investigate the expressions of leptin and per- oxisome proliferator-activated receptor y （PPARG） in relation to body mass index （BMI）. METHODS： We evaluated leptin and PPARG expres- sion in 30 adenomas over 1 cm in size by immunohisto- chemical staining. In addition, clinicopathologic features including BMI were assessed. RESULTS： PPARG and leptin expression showed a strong positive correlation （P = 0.035）. The average BMI of the leptin-positive group was higher than that of the leptin-negative group （25.4 ＋ 3.4 kg/m2 vs 22.6 ＋ 2.4 kg/m2, P = 0.018）, and leptin expression was sig- nificantly correlated with high BMI （P = 0.024）. Leptinexpression was more frequently observed in intermedi- ate/high grade dysplasia than in low grade dysplasia （P = 0.030）. However, PPARG expression was not cor- related with BMI and grade of dysplasia. CONCLUSION： BMI has influenced on the leptin ex- pression of colorectal adenoma. The exact mechanism underlies the strong correlation between leptin and PPARG expression needs further study.

不吃早餐，大脑照样正常“上班”

肚子饿的时候，胃会分泌饥饿素，这种激素主要活动在下视丘里，具有促进食欲的功能。当我们断食时，血液中饥饿素的浓度会变高，一旦我们开始进食。血液中饥饿素的浓度就会开始降低。苗条的人，血液中饥饿素的浓度都比较高。肥胖的人则比较低。具有和饥饿素相反作用的，是脂肪细胞所分泌的瘦体素。当瘦体素这种激素增加时．就会刺激饱食中枢，进而抑制摄食中枢，使得食欲下降。

Effect of low-frequency electroacupuncture on pancreatic endocrine system in patients with simple obesity

Objective： To observe different efficacies of low-frequency electroacupuncture（EA） on pancreatic endocrine system in male and female patients with simple obesity due to spleen deficiency-related dampness. Methods： A total of 80 simple obesity patients were assigned to a male group（n=37） and a female group（n=43）. Both groups received a 30-minute low-frequency EA at Yinlingquan（SP 9）, Sanyinjiao（SP 6）, Zusanli（ST 36）, Fenglong（ST 40）, Quchi（LI 11）, Tianshu（ST 25）, Zhongwan（CV 12）, Shuifen（CV 9）, Qihai（CV 6） and Guanyuan（CV 4）. The treatment was done once a day, and 10 times made up a course of treatment. Patients in both groups were treated for 2 courses. Then the changes in body mass index（BMI）, serum insulin, insulin antibodies and leptin level in the two groups were observed and analyzed. Results： After treatment, the BMI, serum insulin, insulin antibodies and leptin levels were significantly reduced in both groups（P〈0.01 or P〈0.05）; the BMI and serum insulin concentration were more significantly reduced in the male group than those in the female group（both P〈0.01）; and the leptin level was more significantly reduced in the female group than that in the male group（P〈0.01）. Conclusion： EA can significantly regulate BMI and pancreatic endocrine system in both men and women with simple obesity; however, there is a gender difference： better effect for men in reducing BMI and serum insulin and better effect for women in reducing serum leptin level.

Influence of catgut implantation at acupoints on leptin and insulin resistance in simple obesity rats

OBJECTIVES:To investigate the influence of catgut implantation at acupoints on leptin resistance(LR) and insulin resistance(IR) in the simple obesity rat.METHODS:Rats were made obese with high-fat diets,after which surgical catgut was implanted at Zusanli(ST 36) and Neiting(ST 44) acupoints once a week for 4 weeks(implantation group).Rats from the implantation group were compared with normal rats and unoperated obese rats(control group).Gene expression of the leptin receptor(OB-R) was evaluated using RT-PCR and northern blot.Serum and hypothalamus leptin and insulin(INS) levels were determined by radioimmunoassay.Body weight,Lee's index,body fat,serum and hypothalamus leptin and INS levels,and hypothalamic OB-R gene expression were determined before and after treatment.RESULTS:Body weights,Lee's index,body fat,and serum leptin and INS levels were significantly higher in obese than in normal rats.Hypothalamic leptin and INS levels and OB-R gene expression were significantly lower in obese rats.Catgut implantation at acupoint promoted weight loss and decreased serum leptin and INS levels.Hypothalamic leptin and INS levels and OB-R gene expression increased significantly.CONCLUSIONS:Catgut implantation at acupoint adjusts central and peripheral leptin and promotes hypothalamic OB-R gene expression.This may be an important method for regulation of LR,IR and abnormal endocrinology and metabolism.

Leptin in normal physiology and leptin resistance

Since the discovery of leptin as an adipokine in 1994, much progress has been made in the research about leptin. Circulating leptin binds to leptin receptor, activates STAT3-dependent and STAT3-independent signaling pathways, and plays an effective role in energy home- ostasis, neuroendocrine function and metabolism mainly through acting on the central nervous system, especially the hypothalamus. Leptin resistance is considered as a key risk factor for obesity. Various mechanisms have been formu- lated in order to explain leptin resistance, including impairment in leptin transport, attenuation in leptin sig- naling, ER stress, inflammation and deficiency in autop- hagy. Here, we review our current knowledge about leptin action, leptin signaling and leptin resistance, hoping to provide new ideas for the battle against obesity.

Generation of obese rat model by transcription activator-like effector nucleases targeting the leptin receptor gene

The laboratory rat is a valuable mammalian model organism for basic research and drug discovery. Here we demonstrate an efficient methodology by applying transcription activator-like effector nucleases(TALENs) technology to generate Leptin receptor(Lepr) knockout rats on the Sprague Dawley(SD) genetic background. Through direct injection of in vitro transcribed m RNA of TALEN pairs into SD rat zygotes, somatic mutations were induced in two of three resulting pups. One of the founders carrying bi-allelic mutation exhibited early onset of obesity and infertility. The other founder carried a chimeric mutation which was efficiently transmitted to the progenies. Through phenotyping of the resulting three lines of rats bearing distinct mutations in the Lepr locus, we found that the strains with a frame-shifted or premature stop codon mutation led to obesity and metabolic disorders. However, no obvious defect was observed in a strain with an in-frame 57 bp deletion in the extracellular domain of Lepr. This suggests the deleted amino acids do not significantly affect Lepr structure and function. This is the first report of generating the Lepr mutant obese rat model in SD strain through a reverse genetic approach. This suggests that TALEN is an efficient and powerful gene editing technology for the generation of disease models.

Assessment of ghrelin and leptin receptor levels in postmenopausal women who received oral or transdermal menopausal hormonal therapy

Objective： In postmenopausal women, an increased leptin concentration and reduced levels of ghrelin and adiponectin were observed. The aim of this study was to evaluate the concentrations of the active form of ghrelin, total ghrelin, leptin receptor, lipoprotein（a） （Lp（a））, and plasminogen activator inhibitor type 1 （PAl-l） in postmenopausal women who received oral or transdermal menopausal hormonal therapy （MHT）. Methods： The study involved 76 healthy women： 46 women aged from 44 to 58 years who received oral （26） or transdermal （20） MHT; the control group consisted of 30 women aged from 44 to 54 years who did not receive MHT. The plasma concentrations of total ghrelin, the active form of ghrelin, Lp（a）, and PAI-I：Ag were measured by enzyme-linked immunosorbent assay （ELISA）. The concentration of the leptin receptor was measured by enzyme immunometric assay （EIA）. Results： We observed a significantly higher concentration o~ total ghrelin and the active form of ghrelin in women who received transdermal MHT in comparison with those who took oral MHT. We also found a significantly lower concentration of total ghrelin in women who received oral MHT compared with the control group. A higher concentration of PAl-1 ：Ag was found in the group of women who took transdermal MHT in comparison with those who took oral MHT and with the control group. The differences were statistically significant. Additionally, we found a significant negative correlation between the concentrations of total ghrelin and PAl-1 ：Ag and a positive correlation between the concentrations of total ghrelin and leptin receptor in women who received transdermal MHT. Conclusions： The study showed that women who used transdermal MHT had higher levels of total ghrelin than women who took oral MHT. This indicates a beneficial effect of the transdermal route of MHT. However, transdermal therapy was associated with adverse effects with regard to the observed higher levels of PAl-1 ：Ag, which in turn, can lead to a reduction in fibrinolytic activity.