GAS6 and sAXL serum levels in heart failure

Background: Heart failure (HF) is known as an abnormality of the cardiac structure or function that leads to impaired delivery of oxygen to the tissues of the body. This syndrome can be classified in reduced or systolic (HFREF) and preserved or diastolic EF1,2 (HFPEF). A previous study proposed, for the first time in 2014, the participation and expression of a member of TAM receptors, AXL in the pathology of HF. This protein has been related with the clearance of apoptotic cells, the control of the inflammatory response, fibrosis and other mechanisms that participate in HF events. Objectives: The aim of this study is to find out if the soluble form of the protein tyrosine kinase receptor AXL and its ligand, GAS6, are altered in sera of patients suffering of these conditions and whether they may be eligible for future diagnostic and/or prognostic analysis. Methods and results: We used the Enzyme-Linked Immunosorbent Assay (ELISA) technique in order to quantify GAS6 and sAXL serum levels of patients affected by HFPEF and HFREF. A total of 167 patients were tested: 68 patients did not have HF diagnosis and were used as controls for this study, 63 patients had HFPEF and 36 had HFREF. We obtained higher levels of sAXL and GAS6 in HF groups compared with the control group, but they did not reach statistical significance at the 95% confidence level. Conclusions: We could not confirm the diagnostic usefulness of sAXL or its ligand GAS6 for HF in our cohort of patients. To reach conclusive information regarding this issue, we propose the following actions. First, enlarge the number of patient¿s samples in the 3 groups of study. Second, perform a multivariate analysis with other biomarkers, such as brain natriuretic peptides (BNP and NT-proBNP). Finally, obtain samples from patients in different stages of the disease. It would be also essential to improve our knowledge of their molecular roles in the disease, possibly using cellular and animal models.Peer reviewe