What Is H-FABP？

Fatty acid binding protein is a family of homologous small molecule intracellular proteins with a molecular weight of 14000-16000. It is widely present in cells with active fatty acid metabolism. At present, at least 9 types of FABP have been found, namely liver type (L, Z-protein, FABP1), intestinal type (I, FABP2), heart type (H, FABP3), adipocyte type (A, FABP4), brain type (B, FABP6), ileum type (I1), epithelial cell type (E, PABP5), myelin type (My, MP2), and testis type. They are named after the first tissue isolated and identified. The amino acid sequences of different types of FABP have 38%-70% homology.

Heart type fatty acid binding protein（H-FABP） is one type of FABP, which exists specifically in myocardial tissue, red skeletal muscle, smooth muscle cells of the aortic wall, endothelial cells, parietal cells of gastric glands and testicular interstitial cells. A small amount exists in kidney, white skeletal muscle, adrenal glands, brain, but H-FABP is not distributed in liver and adipose tissue. Heart-type fatty acid binding protein accounts for about 4%-8% of all soluble proteins in the heart.

H-FABP is highly specific, and its expression concentration in the heart is 10 times that of skeletal muscle. Under normal circumstances, H-FABP is present in large quantities in myocardial cells. When myocardial cells are damaged, they will quickly flow into the blood, causing the activity of serum H-FABP to increase rapidly, and finally be excreted from the body through urine (excreted by the kidneys). When myocardial cells are no longer damaged, the concentration of H-FABP will drop rapidly.

Clinical application of H-FABP

1、Early diagnosis of AMI:

Cardiac troponin I (cTnI), myoglobin (MYO) and serum creatine kinase isoenzyme B (CK-MB) are the most commonly used biomarkers for evaluating the occurrence of AMI in hospitals. However, cTnI has low sensitivity in the first few hours after AMI; MYO has high sensitivity and rises rapidly after AMI, but has poor cardiac specificity; CK-MB has always been considered the most widely used biomarker of myocardial injury, but it is released into the blood relatively late after the onset of AMI (within 6 hours). H-FABP is highly sensitive to myocardial ischemic injury and can be detected 1 hour after AMI. This suggests that H-FABP is an ideal serum marker for diagnosing AMI. acute dyspnea.tration change from 0 to 3h is ≥ 50% (and the 3h hs-cTn level is higher than 99^thURL), NSTEMI can be considered.

2、Assessment of myocardial infarction area

The infarction area after AMI can reflect the degree of weakening of ventricular function, so the size of the infarction area plays a very important role in prognosis assessment. H-FABP is excreted through the kidneys. In order to avoid overestimation of the infarction area due to renal insufficiency, the clearance rate of FABP within 24 hours is measured to reliably assess the size of the infarction area. 

3、Markers of myocardial ischemia-reperfusion injury

In order to effectively eliminate coronary artery occlusion and reperfuse the AMI part, timely and effective reperfusion and opening of blood vessels is the key to improving prognosis and reducing mortality. After successful perfusion, H-FABP in plasma increases rapidly, and the prediction accuracy of the relative increase rate in the first hour is higher than 93%. When perfusion is unsuccessful, the increase rate of plasma H-FABP is very slow. Therefore, H-FABP can be used as a serum marker for the success of ischemia-reperfusion.

4、Used for prognostic assessment of heart failure (HF)

Studies have shown that elevated H-FABP levels are positively correlated with heart failure. The more severe the heart failure, the higher the proportion of H-FABP elevation. H-FABP is an ideal indicator for judging the prognosis of HF. Combined detection of H-FABP and BNP or NT-proBNP helps improve HF diagnosis and prognosis prediction.

Clinical application of combined detection of H-FABP and cTnI?

1、H-FABP is an early marker for the diagnosis of acute myocardial infarction. Within 12 hours after the onset of chest pain, its sensitivity is better than that of cTnI. The sensitivity, specificity, positive predictive value and negative predictive value of H-FABP and cTnI combined detection are better than those of cTnI/CK-MB/MYO combined detection. Therefore, it can quickly diagnose or exclude suspected AMI patients, which is more conducive to the identification and rescue treatment of emergency patients.

2、Combined detection of H-FABP and cTnI, combined with electrocardiogram results, can significantly improve the exclusion rate of suspected AMI in emergency patients. Research in Manchester shows that using this method can increase the exclusion rate of patients with suspected AMI in the emergency department from 27.7% to 48.8%, and also save patients' hospitalization time and hospitalization expenses.

The ReLIA H-FABP Immunoassay is CE-marked cleared. For more details on ReLIA H-FABP Immunoassay products and prices please contact us at  marketing@ReLIAchina.com

References

[1] Ye X D, He Y, Wang S, et al. Heart-type fatty acid binding protein (H-FABP) as a biomarker for acute myocardial injury and long-term post-ischemic prognosis.[J]. Acta Pharmacologica Sinica, 2018.

[2] Ishii J, Nagamura Y, Nomura M, et al. Early detection of successful coronary reperfusion based on serum concentration of human heart-type cytoplasmic fatty acid-binding protein. Clin Chim Acta, 1997, 262: 13-27.

[3] Body R, Carley S, Burrows G, Pemberton P, Mackway-Jones K. Cardiac fatty acid binding protein and high-sensitivity troponin binding assays in the emergency department. 14th International Conference on Emergency Medicine. Acad Emerg Med. 2012, 19(6): 748-749.

[4] McCann CJ, Glover BM, Menown IB, Moore MJ, McEneny J, Owens CG, Smith B, Sharpe PC, Young IS, Adgey JA. Comparison of novel biomarkers of acute myocardial infarction with cardiac troponin T. Eur. Heart J. 2008, 29(23): 2843-50.