Differential Interventional Effects of Omega-6 and Omega-3 Polyunsaturated Fatty Acids on High Fat Diet-Induced Obesity and Hepatic Pathology.

Current Dietary Guidelines for Americans recommend replacing saturated fat (SFA) intake with polyunsaturated fatty acids (PUFAs) and monosaturated fatty acids (MUFAs) but do not specify the type of PUFAs, which consist of two functionally distinct classes: omega-6 (n-6) and omega-3 (n-3) PUFAs. Given that modern Western diets are already rich in n-6 PUFAs and the risk of chronic disease remains high today, we hypothesized that increased intake of n-3 PUFAs, rather than n-6 PUFAs, would be a beneficial intervention against obesity and related liver diseases caused by high-fat diets. To test this hypothesis, we fed C57BL/6J mice with a high-fat diet (HF) for 10 weeks to induce obesity, then divided the obese mice into three groups and continued feeding for another 10 weeks with one of the following three diets: HF, HF+n-6 (substituted half of SFA with n-6 PUFAs), and HF+n-3 (substituted half of SFA with n-3 PUFAs), followed by assessment of body weight, fat mass, insulin sensitivity, hepatic pathology, and lipogenesis. Interestingly, we found that the HF+n-6 group, like the HF group, had a continuous increase in body weight and fat mass, while the HF+n-3 group had a significant decrease in body weight and fat mass, although all groups had the same calorie intake. Accordingly, insulin resistance and fatty liver pathology (steatosis and fat levels) were evident in the HF+n-6 and HF groups but barely seen in the HF+n-3 group. Furthermore, the expression of lipogenesis-related genes in the liver was upregulated in the HF+n-6 group but downregulated in the HF+n-3 group. Our findings demonstrate that n-6 PUFAs and n-3 PUFAs have differential effects on obesity and fatty liver disease and highlight the importance of increasing n-3 PUFAs and reducing n-6 PUFAs (balancing the n-6/n-3 ratio) in clinical interventions and dietary guidelines for the management of obesity and related diseases.

Omega-3 Polyunsaturated Fatty Acids Protect against High-Fat Diet-Induced Morphological and Functional Impairments of Brown Fat in Transgenic Fat-1 Mice.

The role of omega-3 polyunsaturated fatty acids (n-3 PUFAs) in the regulation of energy homeostasis remains poorly understood. In this study, we used a transgenic fat-1 mouse model, which can produce n-3 PUFAs endogenously, to investigate how n-3 PUFAs regulate the morphology and function of brown adipose tissue (BAT). We found that high-fat diet (HFD) induced a remarkable morphological change in BAT, characterized by "whitening" due to large lipid droplet accumulation within BAT cells, associated with obesity in wild-type (WT) mice, whereas the changes in body fat mass and BAT morphology were significantly alleviated in fat-1 mice. The expression of thermogenic markers and lypolytic enzymes was significantly higher in fat-1 mice than that in WT mice fed with HFD. In addition, fat-1 mice had significantly lower levels of inflammatory markers in BAT and lipopolysaccharide (LPS) in plasma compared with WT mice. Furthermore, fat-1 mice were resistant to LPS-induced suppression of UCP1 and PGC-1 expression and lipid deposits in BAT. Our data has demonstrated that high-fat diet-induced obesity is associated with impairments of BAT morphology (whitening) and function, which can be ameliorated by elevated tissue status of n-3 PUFAs, possibly through suppressing the effects of LPS on inflammation and thermogenesis.

Label-free aptamer-based sensor for specific detection of malathion residues by surface-enhanced Raman scattering.

A novel label-free aptamer surface-enhanced Raman scattering (SERS) sensor for trace malathion residue detection was proposed. In this process, the binding of malathion molecule with aptamer is identified directly. The silver nanoparticles modified with positively charged spermine served as enhancing and capture reagents for the negatively charged aptamer. Then, the silver nanoparticles modified by aptamer were used to specifically capture the malathion. The SERS background spectra of spermine, aptamer, and malathion were recorded and distinguished with the spectrum of malathion-aptamer. To enhance the characteristic peak signal of malathion captured by the aptamer, the aggregate reagents (NaCl, KCl, MgCl2) were compared and selected. The selectivity of this method was verified in the mixed-pesticide standard solution, which included malathion, phosmet, chlorpyrifos-methyl, and fethion. Results show that malathion can be specifically identified when the mixed-pesticide interferences existed. The standard curve was established, presenting a good linear range of 5×10-7 to 1×10-5mol·L-1. The spiked experiments for tap water show good recoveries from 87.4% to 110.5% with a relative standard deviation of less than 4.22%. Therefore, the proposed label-free aptamer SERS sensor is convenient, specifically detects trace malathion residues, and can be applied for qualitative and quantitative analysis of other pesticides.

[The etiology of neurological disorders in 1 188 elder patients with neuroimaging at geriatric outpatient clinic].

OBJECTIVE: To investigate the etiology of neurological disorders in elderly at outpatient clinic. METHODS: Elderly patients aged 60 years old or more who visited the geriatric neurological outpatient clinic of PLA General Hospital from July 1, 2009 to June 30, 2012 and underwent the brain MRI or CT imaging were retrospectively analyzed. The constituent ratio of common neurological disorders in all patients and patients from different age groups were statistically analyzed based on the information from PRIDE data management system. RESULTS: A total of 1 188 patients were enrolled in this study with well documented record of complaint examination of the nerve system and brain MRI or CT imaging. Common neurological disorders in those patients were cerebrovascular disease(22.39%), mild cognitive impairment and dementia (15.99%), movement disorders including Parkinson disease, Parkinsonism and essential tremor(9.09%), sleep disorders (6.73%) and psychological diseases(6.65%). Spinal degenerative diseases accompanied by neurological symptoms also accounted for 10.52%. Less common causes in those patients were benign paroxysmal positioning vertigo(3.96%), headache and neck pain (3.28%), cranial nerve diseases (2.78%) and intracranial tumors (2.61%). Constituent ratios of mild cognitive impairment and dementia in different age groups were associated with aging, and the same was observed with Parkinson disease. CONCLUSION: The common neurological disorders in the geriatric outpatients are cerebrovascular disease and neurodegenerative diseases including different type of dementia and Parkinson disease. Those disorders should be focused for the prevention and treatment of the nervous system diseases in the elderly.

[Two-dimensional electrophoregram for proteomic analysis of rat brain with intrahippocampal amyloid beta injection and normal rat brain].

OBJECTIVE: To investigate the molecular mechanisms of Alzheimer's disease by comparing global protein patterns in two-dimensional electrophoregram (2-DE) of the brain of rats with intrahippocampal amyloid beta injection and normal rats. METHODS: From adult SD rats with intrahippocampal injection of amyloid beta, 200 microg brain proteins were extracted with 9 mol/L urea, 4% CHAPS, 1% DTT, 0.5% CA and a cocktail of protease inhibitors. Immobilized pH gradient (IPG) isoelectric focusing electrophoresis of the extracted proteins was performed to obtain the electrophoretogram of the first dimension, with the second dimension obtained by vertical SDS-PAGE. The electrophoretograms were visualized using silver staining and analyzed with ImageMaster 2D-Elite software. RESULTS: On average, 496 and 491 protein spots could be obtained in the electrophoregraphs for rats with amyloid beta and the control rats, respectively, and 30 of these spots exhibited quantitative changes. Another 11 and 6 spots were exclusively shown on the protein maps for amyloid beta-treated rats and control rats, respectively. CONCLUSION: The differentially displayed proteins in the brain identified between the rats with intrahippocampal amyloid beta injection and control rats may provide further insight into the pathogenesis of Alzheimer's disease and useful clues for developing new drugs for its treatment.