脂肪酸诱导脂肪细胞促酰化蛋白抵抗及机制研究

目的:观察不同浓度单不饱和脂肪酸(油酸)和饱和脂肪酸(棕榈酸)对3T3-L1(前)脂肪细胞葡萄糖转运的影响,探讨高游离脂肪酸(FFA)负荷在促酰化蛋白(ASP)抵抗形成中的意义,及FFA诱导的3T3-L1(前)脂肪细胞ASP抵抗的机制。方法:体外培养3T3-L1细胞,诱导细胞分化,用不同浓度FFA作用于3T3-L1(前)脂肪细胞,孵育过夜后收获细胞,采用2-脱氧-[3H]-D-葡萄糖掺入法,观察3T3-L1成熟脂肪细胞和前脂肪细胞基础状态和ASP刺激状态的葡萄糖摄取率;采用Western blotting法检测基础状态和ASP刺激的鸟苷酸结合蛋白alpha-q/11(Gαq/11),鸟苷酸结合蛋白beta(Gβ),磷酸化蛋白激酶Calpha(p-PKCα)和磷酸化蛋白激酶Czeta(p-PKCζ)蛋白表达。结果:ASP刺激后,3T3-L1成熟脂肪细胞和前脂肪细胞葡萄糖摄取率分别是基础状态的1.98倍(P0.01)和2.87倍(P0.01)。低浓度FFA不影响ASP刺激的葡萄糖转运;而1.0mmol/L时油酸组和棕榈酸组ASP刺激的成熟脂肪细胞葡萄糖摄取率分别减少47%(P0.05)和34%(P0.05),前脂肪细胞葡萄糖摄取率分别减少43%(P0.05)和62%(P0.01)。1.0mmol/L油酸和棕榈酸抑制成熟脂肪细胞基础状态和ASP刺激的Gβ、Gαq/11、p-PKCα和p-PKCζ蛋白表达,油酸组ASP刺激的蛋白表达分别减少了47%Gβ(P0.01),44%Gαq/11(P0.05)、39%p-PKCα(P0.05)和20%p-PKCζ(P0.05);棕榈酸组也可观察到类似现象(P0.05或P0.01)。在前脂肪细胞,油酸仅抑制ASP刺激的p-PKCα和p-PKCζ(均P0.05)蛋白表达;而棕榈酸下调上述4种信号蛋白的表达(P0.05或P0.01)。结论:油酸或棕榈酸抑制3T3-L1成熟脂肪细胞和前脂肪细胞ASP刺激的葡萄糖转运,证明FFA诱导脂肪细胞产生胰岛素抵抗状态下同时存在ASP抵抗。FFA诱导的ASP抵抗的发生机制与其干扰ASP-C5L2信号转导途径有关。ASP抵抗参与了"脂毒性"-胰岛素抵抗/肥胖症的病理生理过程。     

Increased levels of acylation-stimulating protein in interleukin-6-deficient (IL-6(-/-)) mice

IL-6-deficient (IL-6(-/-)) mice develop obesity at 6-7 months of age. To elucidate the mechanisms of this mature-onset obesity, global gene expression profiles of 3-month-old preobese IL-6(-/-) were compared with those of IL-6(+/+) mice using DNA arrays. Genes that were up-regulated in IL-6(-/-) mice included the factors transthyretin and properdin in white adipose tissue and adipsin in muscle. These factors have been shown to influence the formation of acylation-stimulating protein (ASP), a cleavage product of complement C3. ASP stimulates the synthesis of triacylglycerol in adipocytes, and ASP-deficient mice are resistant to diet-induced obesity. In line with the increases in transthyretin, properdin, and adipsin, ASP levels in serum were increased by 31-54% in IL-6(-/-) compared with IL-6(+/+) mice. Furthermore, IL-6 replacement treatment in IL-6(-/-) mice decreased ASP levels significantly by 25-60%. In conclusion, ASP levels are increased in preobese IL-6(-/-) mice. This increase may result in increased triacylglycerol formation and uptake in IL-6(-/-) adipocytes and thereby contribute to the development of obesity in IL-6(-/-) mice.     

The role of high-sensitivity C-reactive Protein,interleukin-6 and cystatin C in ischemic stroke complicating atrial fibrillation

This study examined the role of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and cystatin C in ischemic stroke complicating atrial fibrillation (AF) and the relationship of systemic inflammation with this disease in order to identify AF patients who are at high risk of stroke and need optimal anticoagulant therapy.A total of 103 AF patients, simple (n=75) or complicated by ischemic stroke (n=28), and 112 control subjects were recruited.IL-6 level was detected by using enzyme linked immunosorbent assay.Cystatin C and hsCRP levels were measured by means of a particle-enhanced immunonephelometric assay.The results showed that the AF patients had higher levels of hsCRP (P=0.004), IL-6 (P=0.000), and cystatin C (P=0.000) than control subjects.Plasma hsCRP level was increased in the AF patients with ischemic stroke as compared to the patients with simple AF (P=0.036).The AF patients who had the level of hsCRP exceeding 3.83 mg/L were at a higher risk than those with hsCRP level lower than 3.83 mg/L (P=0.030).After adjusting for other factors, cystatin C remained positively associated with IL-6 (r=0.613) and hsCRP (r=0.488).It was concluded that hsCRP is positively correlated with ischemic stroke complicating AF and may be a risk factor independent of other risk factors for AF.Elevated cystatin C level is also indicative of the increased risk of AF.     

Molecular study of human herpesvirus 6 and 8 involvement in coronary atherosclerosis and coronary instability

Several lines of evidence suggest the involvement of infectious agents in the pathogenesis of atherosclerosis. Furthermore, a correlation between infection‐driven inflammatory burden and acute manifestation of coronary artery disease has been hypothesized. The aim of this work was to assess whether human herpesvirus (HHV)‐6 and HHV‐8, two DNA viruses with a distinct tropism for endothelium and lymphocytes, may be associated with coronary instability. An age‐ and gender‐matched cross‐sectional study was undertaken in 70 patients with testing of plasma HHV‐6 and HHV‐8 DNA load in different cardiovascular clinical settings: 29 patients with acute myocardial infarction, 21 patients with stable coronary artery disease, and 20 patients without coronary and carotid artery atherosclerosis subjected to cardiac valve replacement. In all patients, HHV‐6 and HHV‐8 plasma DNA was tested by using highly sensitive, calibrated quantitative real‐time PCR assays which employ a synthetic DNA calibrator to adjust for DNA extraction and amplification efficiency. HHV‐8 viremia was undetectable in all three groups. HHV‐6 viremia was detected in a substantial fraction of the samples examined (18.6%) without significant differences among the three groups (ST segment elevation myocardial infarction: 17.2%; stable coronary artery disease: 14.3%; patients without coronary and carotid artery atherosclerosis: 25%). Furthermore, no significant differences in plasma HHV‐6 load were observed amongst the three groups of patients. These findings indicate that coronary instability is not associated specifically with active HHV‐6 or HHV‐8 infection. However, an unusually high rate of active HHV‐6 infection was documented among patients without atherosclerosis admitted to hospital with cardiac disease. J. Med. Virol. 84:1961–1966, 2012. © 2012 Wiley Periodicals, Inc.     

Facial lipectomy

Facial lipectomy is an effective face-lifting technique. Using a line from the malar surface of one side of the face to the submental crease to the malar surface of the other side as a guide, the surgeon removes and sculptures the excess adipose tissue that forms with aging into a youthful firm jawline. We have used this technique in 520 patients since 1971 with excellent results and no complications. More follow-up is needed to establish the long-term results.     

Role of biotransformation in the alterations of chloroform hepatotoxicity produced by Kepone and mirex

A previous report demonstrated that pretreatment of mice with Kepone resulted in marked potentiation of CHCl₃-induced hepatotoxicity whereas pretreatment with a structural analog, mirex, had no effect on the liver injury produced by a challenging dose of CHCl₃. To determine some of the possible mechanisms for this difference in potentiating ability, various parameters were studied. The hepatic content of mirex and Kepone was determined 42 hr after the oral administration of each agent to male Swiss-Webster mice. The concentration of mirex within the liver increased in a dose-related fashion. Following a single dose (50 mg/kg) of either mirex or Kepone, the hepatic content of each agent was approximately equal. Kepone (50 mg/kg, po) had no effect on mouse hepatic glutathione content at 18 hr. The relationship between the effects of mirex and Kepone on microsomal mixed function oxidase (MFO) activity and the in vivo and in vitro irreversible binding of ¹⁴CHCl₃ reactive metabolite(s) to hepatic constituents was assessed at 18 hr. Mirex pretreatment (10, 50, 250 mg/kg) resulted in a more profound effect on hepatic MFO activity than did pretreatment with Kepone (50 mg/kg). However, mirex pretreatment (50 mg/kg) did not alter either the in vivo or in vitro irreversible binding of ¹⁴CHCl₃-derived radioactivity to mouse hepatic constituents. In contrast, pretreatment of mice with Kepone (50 mg/kg) resulted in profound increases in both the in vivo and in vitro irreversible binding of ¹⁴CHCl₃ metabolites. Thus it appears that the disparate potentiating abilities of mirex and Kepone are related to a difference in the capacity of these agents to increase the activity of the CHCl₃ bioactivation system of the liver.