Fatty acid transporters in plasma membranes of cardiomyocytes in patients with dilated cardiomyopathy.

Background: Long-chain fatty acids are one of the major cardiac energy substrates. Although the exact mechanism of myocardial fatty acid uptake is not known, several proteins, including the integral membrane proteins FATP1 (fatty acid transport protein 1) and FAT (fatty acid translocase), are being implicated in this process. The aim of this study was to further investigate FATP1 and FAT in the heart and its potential role in myocardial fatty acid utilization. -

Methods: The expression of FATP1 and FAT in mouse myocardium and in myocardial biopsies of 14 patients with different cardiomyopathies was detected by immunocytochemistry and visualized with a laser scanning microscope. -

Results: FAT and FATP1 are co-expressed on the plasma membrane of cardiac endothelial cells and on the sarcolemma of cardiomyocytes. The staining-pattern and the intensity of signal for both transport proteins was constant in different cardiomyopathies compared with the expression in biopsies of patients with other cardiac diseases and the expression in the myocardium of healthy mice. -

Conclusion: Cardiac endothelial cells and cardiomyocytes express FAT and FATP1 in vivo, suggesting an active part of these proteins in the uptake process of long-chain fatty acids. However, we did not find evidence for an altered expression of fatty acid transport proteins in patients with dilated cardiomyopathy, suggesting that these proteins are of minor importance in this kind of heart failure.