Scholar Hub/Chủ đề/#triglyceride/
Triglyceride là một loại lipid quan trọng với vai trò chính là lưu trữ năng lượng trong các tế bào mỡ thông qua cấu trúc hóa học của glycerol và ba axit béo. Đóng vai trò như nguồn cung cấp năng lượng dự trữ, triglyceride được sử dụng khi cơ thể cần thông qua enzyme lipase. Chúng cũng bảo vệ cơ thể khỏi lạnh và sóc cơ học. Trong chế độ dinh dưỡng, triglyceride từ thực phẩm cung cấp năng lượng nhưng cần duy trì ở mức an toàn để tránh nguy cơ bệnh tim mạch và xơ vữa động mạch. Hiểu biết về chúng giúp cải thiện sức khỏe và phòng ngừa bệnh tật.
Triglyceride: Khái niệm và Vai Trò Sinh Học
Triglyceride là một loại lipid nổi tiếng, đóng vai trò quan trọng trong cơ thể sống. Được cấu thành từ một phân tử glycerol liên kết với ba phân tử axit béo, triglyceride là hình thức lưu trữ năng lượng chính trong các tế bào mỡ của động vật.
Cấu Trúc Hóa Học
Mỗi phân tử triglyceride gồm ba axit béo gắn kết với nhóm hydroxyl của glycerol thông qua liên kết ester. Các axit béo này có thể bão hòa hoặc không bão hòa, và sự khác biệt này ảnh hưởng đến tính chất vật lý và hóa học của triglyceride, chẳng hạn như điểm nóng chảy.
Chức Năng Sinh Học
Triglyceride chủ yếu đóng vai trò như một nguồn cung cấp năng lượng dự trữ. Khi cơ thể cần năng lượng, các enzyme lipase sẽ phân giải triglyceride thành glycerol và axit béo tự do để sử dụng trong quá trình trao đổi chất. Ngoài ra, triglyceride còn giúp bảo vệ cơ thể chống lại lạnh và sóc cơ học nhờ vào lớp mỡ bảo vệ.
Chuyển Hóa và Lưu Trữ
Sau khi được tiêu hóa và hấp thu, triglyceride được đóng gói vào các hạt chylomicron và vận chuyển qua hệ tuần hoàn để dự trữ trong mô mỡ. Cơ chế này giúp duy trì năng lượng cần thiết cho cơ thể trong những lúc cần thiết, chẳng hạn như lúc đói.
Vai Trò trong Chế Độ Dinh Dưỡng
Triglyceride là thành phần chính trong chất béo từ thực phẩm, bao gồm cả dầu thực vật và mỡ động vật. Chúng cung cấp phần lớn năng lượng trong chế độ ăn uống và ảnh hưởng đến tình trạng dinh dưỡng và sức khỏe. Điều quan trọng là phải duy trì mức triglyceride trong phạm vi an toàn để giảm nguy cơ các bệnh tim mạch.
Ảnh Hưởng đến Sức Khỏe
Mức triglyceride cao trong máu, điều kiện gọi là hypertriglyceridemia, có thể dẫn đến nhiều vấn đề sức khỏe nghiêm trọng, bao gồm bệnh tim mạch và xơ vữa động mạch. Để kiểm soát, việc điều chỉnh chế độ ăn uống và hoạt động thể chất là cần thiết.
Kết Luận
Hiểu biết về triglyceride và vai trò của nó trong cơ thể giúp chúng ta tiếp cận một cách có khoa học đối với chế độ dinh dưỡng và các phương pháp phòng ngừa bệnh tật. Duy trì mức triglyceride trong giới hạn khuyến nghị là quan trọng cho một sức khỏe tốt.
Quantitative Determination of Serum Triglycerides by the Use of Enzymes Clinical Chemistry - Tập 19 Số 5 - Trang 476-482 - 1973
Abstract
We describe a novel method for determining serum triglycerides, in which an enzymatic hydrolysis replaces the more commonly used saponification procedure. Under the conditions of the assay, the enzymatic hydrolysis can be completed in less than 10 min by the combined action of a microbial lipase and a protease. We have been able to demonstrate complete hydrolysis of triglycerides by thin-layer chromatography of the reaction products, by recovery of glycerol from sera of known triglycerides content, and by comparison of triglyceride assays on a number of sera assayed by our method vs. the AutoAnalyzer procedure. The hydrolysis is directly coupled to the enzymatic determination of glycerol, and is followed through absorbance changes at 340 nm. The assay is simple, rapid, and requires only 50 µl or less of sample. Because the enzymes used do not release glycerol from other compounds in serum, the hydrolysis can be considered specific for triglycerides.
Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide. Clinical Chemistry - Tập 28 Số 10 - Trang 2077-2080 - 1982
Abstract
In this direct colorimetric procedure, serum triglycerides are hydrolyzed by lipase, and the released glycerol is assayed in a reaction catalyzed by glycerol kinase and L-alpha-glycerol-phosphate oxidase in a system that generates hydrogen peroxide. The hydrogen peroxide is monitored in the presence of horseradish peroxidase with 3,5-dichloro-2-hydroxybenzenesulfonic acid/4-aminophenazone as the chromogenic system. The high absorbance of this chromogen system at 510 nm affords useful results with a sample/reagent volume ratio as low as 1:150, and a blank sample measurement is not needed. A single, stable working reagent is used; the reaction is complete in 15 min at room temperature. The standard curve is linear for triglyceride concentrations as great as 13.6 mmol/L. Average analytical recovery of triglycerides in human sera is 100.1%, and within-run and between-run precision studies showed CVs of less than or equal to 1.6 and less than or equal to 3.0%, respectively. The method is suitable for automation.
Triglyceride accumulation protects against fatty acid-induced lipotoxicity Proceedings of the National Academy of Sciences of the United States of America - Tập 100 Số 6 - Trang 3077-3082 - 2003
Excess lipid accumulation in non-adipose tissues is associated with insulin resistance, pancreatic β-cell apoptosis and heart failure. Here, we demonstrate in cultured cells that the relative toxicity of two common dietary long chain fatty acids is related to channeling of these lipids to distinct cellular metabolic fates. Oleic acid supplementation leads to triglyceride accumulation and is well tolerated, whereas excess palmitic acid is poorly incorporated into triglyceride and causes apoptosis. Unsaturated fatty acids rescue palmitate-induced apoptosis by channeling palmitate into triglyceride pools and away from pathways leading to apoptosis. Moreover, in the setting of impaired triglyceride synthesis, oleate induces lipotoxicity. Our findings support a model of cellular lipid metabolism in which unsaturated fatty acids serve a protective function against lipotoxicity though promotion of triglyceride accumulation.
Magnetic resonance spectroscopy to measure hepatic triglyceride content: prevalence of hepatic steatosis in the general population American Journal of Physiology - Endocrinology and Metabolism - Tập 288 Số 2 - Trang E462-E468 - 2005
Despite the increasing prevalence of nonalcoholic fatty liver disease (NAFLD), the criteria used to diagnose the disorder remain poorly defined. Localized proton magnetic resonance spectroscopy (MRS) accurately measures hepatic triglyceride content (HTGC) but has been used only in small research studies. Here, MRS was used to analyze the distribution of HTGC in 2,349 participants from the Dallas Heart Study (DHS). The reproducibility of the procedure was validated by showing that duplicate HTGC measurements were high correlated ( r = 0.99, P < 0.001) and that the coefficient of variation between measurements was low (8.5%). Intake of a high-fat meal did not significantly affect the measurements, and values were similar when measurements were made from the right and left hepatic lobes. To determine the “upper limit of normal” for HTGC, the distribution of HTGC was examined in the 345 subjects from the DHS who had no identifiable risk factors for hepatic steatosis (nonobese, nondiabetic subjects with minimal alcohol consumption, normal liver function tests, and no known liver disease). The 95th percentile of HTGC in these subjects was 5.56%, which corresponds to a hepatic triglyceride level of 55.6 mg/g. With this value as a cutoff, the prevalence of hepatic steatosis in Dallas County was estimated to be 33.6%. Thus MRS provides a sensitive, quantitative, noninvasive method to measure HTGC and, when applied to a large urban US population, revealed a strikingly high prevalence of hepatic steatosis.
Joint effects of serum triglyceride and LDL cholesterol and HDL cholesterol concentrations on coronary heart disease risk in the Helsinki Heart Study. Implications for treatment. Ovid Technologies (Wolters Kluwer Health) - Tập 85 Số 1 - Trang 37-45 - 1992
BACKGROUND
We studied the joint effect of baseline triglyceride and lipoprotein cholesterol levels on the incidence of cardiac end points in the trial group (n = 4,081) of the Helsinki Heart Study, a 5-year randomized coronary primary prevention trial among dyslipidemic middle-aged men. The relative risks (RR) were calculated using Cox proportional hazards models with a dummy variable technique that allows simultaneous study of subgroup combinations from the placebo and treatment groups.
METHODS AND RESULTS
In the placebo group (n = 2,045), the low density lipoprotein cholesterol (LDL-C)/high density lipoprotein cholesterol (HDL-C) ratio was the best single predictor of cardiac events. This ratio in combination with the serum triglyceride level revealed a high-risk subgroup: subjects with LDL-C/HDL-C ratio greater than 5 and triglycerides greater than 2.3 mmol/l had a RR of 3.8 (95% CI, 2.2-6.6) compared with those with LDL-C/HDL-C ratio less than or equal to 5 and triglyceride concentration less than or equal to 2.3 mmol/l. In subjects with triglyceride concentration greater than 2.3 mmol/l and LDL-C/HDL-C ratio less than or equal to 5, RR was close to unity (1.1), whereas in those with triglyceride level less than or equal to 2.3 mmol/l and LDL-C/HDL-C ratio greater than 5, RR was 1.2. The high-risk group with LDL-C/HDL-C ratio greater than 5 and triglyceride level greater than 2.3 mmol/l profited most from treatment with gemfibrozil, with a 71% lower incidence of coronary heart disease events than the corresponding placebo subgroup. In all other subgroups, the reduction in CHD incidence was substantially smaller.
CONCLUSIONS
Serum triglyceride concentration has prognostic value, both for assessing coronary heart disease risk and in predicting the effect of gemfibrozil treatment, especially when used in combination with HDL-C and LDL-C.
A peroxidase-coupled method for the colorimetric determination of serum triglycerides. Clinical Chemistry - Tập 29 Số 3 - Trang 538-542 - 1983
Abstract
We describe an enzymatic method for rapid, precise measurement of serum triglycerides with use of sample:reagent ratios as large as 1:200. Hydrolysis of triglycerides is catalyzed by lipase to produce glycerol and free fatty acids. The glycerol generated is then phosphorylated by adenosine 5'-triphosphate in the presence of glycerol kinase. Oxidation of the resulting glycerol 3-phosphate to produce hydrogen peroxide is catalyzed by L-alpha-glycerophosphate oxidase. An intense red chromogen is produced by the peroxidase-catalyzed coupling of 4-aminoantipyrene and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate with hydrogen peroxide. This sensitive chromogen system not only permits use of unusually small sample volumes, it also facilitates a linear response to serum triglyceride concentrations up to at least 10 g/L while displaying good Ringbom (measure of accuracy) characteristics.
Secondary Prevention by Raising HDL Cholesterol and Reducing Triglycerides in Patients With Coronary Artery Disease Ovid Technologies (Wolters Kluwer Health) - Tập 102 Số 1 - Trang 21-27 - 2000
Background
—Coronary heart disease patients with low high-density lipoprotein cholesterol (HDL-C) levels, high triglyceride levels, or both are at an increased risk of cardiovascular events, but the clinical impact of raising HDL-C or decreasing triglycerides remains to be confirmed.
Methods and Results
—In a double-blind trial, 3090 patients with a previous myocardial infarction or stable angina, total cholesterol of 180 to 250 mg/dL, HDL-C ≤45 mg/dL, triglycerides ≤300 mg/dL, and low-density lipoprotein cholesterol ≤180 mg/dL were randomized to receive either 400 mg of bezafibrate per day or a placebo; they were followed for a mean of 6.2 years. The primary end point was fatal or nonfatal myocardial infarction or sudden death. Bezafibrate increased HDL-C by 18% and reduced triglycerides by 21%. The frequency of the primary end point was 13.6% on bezafibrate versus 15.0% on placebo (
P
=0.26). After 6.2 years, the reduction in the cumulative probability of the primary end point was 7.3%, (
P
=0.24). In a post hoc analysis in the subgroup with high baseline triglycerides (≥200 mg/dL), the reduction in the cumulative probability of the primary end point by bezafibrate was 39.5% (
P
=0.02). Total and noncardiac mortality rates were similar, and adverse events and cancer were equally distributed.
Conclusions
—Bezafibrate was safe and effective in elevating HDL-C levels and lowering triglycerides. An overall trend in a reduction of the incidence of primary end points was observed. The reduction in the primary end point in patients with high baseline triglycerides (≥200 mg/dL) requires further confirmation.