Human Fatty Acid Binding Protein 4 (FABP4) ELISA Kit
FABP-4, also termed adipocyte fatty-acid binding protein (A-FABP) or AP2, has been shown to play a key role in obesity and metabolic syndrome. A-FABP knockout mice are substantially protected from insulin resistance, dyslipidemia, type 2 diabetes and fatty liver disease, despite of increased adipocity.
In clinical studies, increased circulating A-FABP levels are found in obese subjects and associated with non-alcoholic fatty liver disease, stroke, and carotid atherosclerosis.
PRINCIPLE OF THE ASSAY
This assay is a quantitative sandwich ELISA. The immunoplate is pre-coated with a mouse monoclonal antibody specific for human FABP4. Standards and samples are pipetted into the wells and any Human FABP4 present is bound by the immobilized antibody. After washing away any unbound substances, a biotin labelled polyclonal antibody specific for human FABP4 is added to the wells. After wash step to remove any unbound reagents, streptavidin-HRP conjugate is added, after the last wash step, an HRP substrate solution is added and colour develops in proportion to the amount of human FABP4 bound initially. The assay is stopped and the optical density of the wells determined using a microplate reader. Since the increases in absorbance are directly proportional to the amount of captured human FABP4, the unknown sample concentration can be interpolated from a reference curve included in each assay.
A. Typical representation of standard curve
The following standard curve is provided for demonstration only. A standard curve should be generated for each set of sample assay.
Absorbance (450 nm)
The lowest level of FABP4 that can be detected by this assay is 0.39 ng/mL.
The antibodies used in this assay are specific to human FABP4 and do not cross-react with mouse and rat FABP4, and other cytokine or hormone molecules.
Intra-assay Precision (Precision within an assay) C.V. <4.1%.
Inter-assay Precision (Precision between assays) C.V. <4.5%.
PUBLICATIONS CITING THIS PRODUCT
- Alkharfy KM, Al-Daghri NM, Vanhoutte PM, Krishnaswamy S, Xu A. Serum retinol-binding protein 4 as a marker for cardiovascular disease in women. PloS one. 2012 Oct 31;7(10):e48612.
- Ong KL, Rye KA, O'Connell R, Jenkins AJ, Brown C, Xu A, Sullivan DR, Barter PJ, Keech AC, FIELD Study Investigators. Long-term fenofibrate therapy increases fibroblast growth factor 21 and retinol-binding protein 4 in subjects with type 2 diabetes. The Journal of Clinical Endocrinology & Metabolism. 2012 Dec 1;97(12):4701-8.
- Liu M, Zhou M, Bao Y, Xu Z, Li H, Zhang H, Zhu W, Zhang J, Xu A, Wei M, Jia W. Circulating adipocyte fatty acid-binding protein levels are independently associated with heart failure. Clinical science. 2013 Jan 1;124(2):115-22.
- Li X, Tse HF, Yiu KH, Zhang C, Jin LJ. Periodontal therapy decreases serum levels of adipocyte fatty acid‐binding protein in systemically healthy subjects: a pilot clinical trial. Journal of periodontal research. 2013 Jun;48(3):308-14.
- Heilbronn LK, Campbell LV, Xu A, Samocha-Bonet D. Metabolically protective cytokines adiponectin and fibroblast growth factor-21 are increased by acute overfeeding in healthy humans. PloS one. 2013 Oct 18;8(10):e78864.
- Chen DL, Liess C, Poljak A, Xu A, Zhang J, Thoma C, Trenell M, Milner B, Jenkins AB, Chisholm DJ, Samocha-Bonet D. Phenotypic characterization of insulin-resistant and insulin-sensitive obesity. The Journal of Clinical Endocrinology & Metabolism. 2015 Nov 1;100(11):4082-91.
- Elie AG, Jensen PS, Nissen KD, Geraets IM, Xu A, Song E, Hansen ML, Irmukhamedov A, Rasmussen LM, Wang Y, De Mey JG. Adipokine imbalance in the pericardial cavity of cardiac and vascular disease patients. PloS one. 2016 May 3;11(5):e0154693.
- Chen DL, Brown R, Liess C, Poljak A, Xu A, Zhang J, Trenell M, Jenkins A, Chisholm D, Samocha-Bonet D, Macefield VG. Muscle sympathetic nerve activity is associated with liver insulin sensitivity in obese non-diabetic men. Frontiers in physiology. 2017 Feb 28;8:101.
- Zhang C, Li T, Chiu KY, Wen C, Xu A, Yan CH. FABP4 as a biomarker for knee osteoarthritis. Biomarkers in medicine. 2018 Feb;12(2):107-18.
- Wong YK, Cheung CY, Tang CS, Au KW, Hai JS, Lee CH, Lau KK, Cheung BM, Sham PC, Xu A, Lam KS. Age-biomarkers-clinical risk factors for prediction of cardiovascular events in patients with coronary artery disease. Arteriosclerosis, thrombosis, and vascular biology. 2018 Oct;38(10):2519-27.
- Lee CH, Cheung CY, Woo YC, Lui DT, Yuen MM, Fong CH, Chow WS, Xu A, Lam KS. Circulating adipocyte fatty acid–binding protein concentrations predict multiple mortality outcomes among men and women with diabetes. Clinical chemistry. 2018 Oct 1;64(10):1496-504.
- Elie AG, Bloksgaard M, Sun WY, Yang K, Man AW, Xu A, Irmukhamedov A, Riber LP, Wang Y, De Mey JG. Local enrichment of fatty acid-binding protein 4 in the pericardial cavity of cardiovascular disease patients. PloS one. 2018 Nov 5;13(11):e0206802.
- Xu Y, Ma X, Pan X, He X, Wang Y, Bao Y. Serum adipocyte fatty acid‐binding protein levels: An indicator of non‐alcoholic fatty liver disease in Chinese individuals. Liver International. 2019 Mar;39(3):568-74.
- Tang A, Coster AC, Tonks KT, Heilbronn LK, Pocock N, Purtell L, Govendir M, Blythe J, Zhang J, Xu A, Chisholm DJ. Longitudinal changes in insulin resistance in normal weight, overweight and obese individuals. Journal of clinical medicine. 2019 May;8(5):623.
- Mak LY, Lee CH, Cheung KS, Wong DK, Liu F, Hui RW, Fung J, Xu A, Lam KS, Yuen MF, Seto WK. Association of adipokines with hepatic steatosis and fibrosis in chronic hepatitis B patients on long‐term nucleoside analogue. Liver International. 2019 Jul;39(7):1217-25.
- Harari A, Coster AC, Jenkins A, Xu A, Greenfield JR, Harats D, Shaish A, Samocha-Bonet D. Obesity and insulin resistance are inversely associated with serum and adipose tissue carotenoid concentrations in adults. The Journal of nutrition. 2020 Jan 1;150(1):38-46.
- Liao B, Geng L, Zhang F, Shu L, Wei L, Yeung PK, Lam KS, Chung SK, Chang J, Vanhoutte PM, Xu A. Adipocyte fatty acid-binding protein exacerbates cerebral ischaemia injury by disrupting the blood–brain barrier. European heart journal. 2020 Sep 1;41(33):3169-80.
- Ong KL, Wu L, Januszewski AS, O'Connell RL, Xu A, Rye KA, Ma RC, Li H, Jenkins AJ, Jia W, Keech AC. Relationships of adipocyte-fatty acid binding protein and lipocalin 2 with risk factors and chronic complications in type 2 diabetes and effects of fenofibrate: A fenofibrate Intervention and event lowering in diabetes sub-study. Diabetes Research and Clinical Practice. 2020 Nov 1;169:108450.
- Nie X, Ma X, Xu Y, Shen Y, Wang Y, Bao Y. Increased Serum Adipocyte Fatty Acid-Binding Protein Levels Are Associated with Decreased Sensitivity to Thyroid Hormones in the Euthyroid Population. Thyroid. 2020 Dec 1;30(12):1718-23.
- Xiao Y, Shu L, Wu X, Liu Y, Cheong LY, Liao B, Xiao X, Hoo RL, Zhou Z, Xu A. Fatty acid binding protein 4 promotes autoimmune diabetes by recruitment and activation of pancreatic islet macrophages. JCI insight. 2021 Apr 8;6(7).