The skin is a flexible organ that forms a barrier between the environment and the body's interior; it is involved in the immune response, in protection and regulation, and is a dynamic environment in which skin lipids play an important role in maintaining homeostasis. The different layers of the skin differ in both the composition and amount of lipids. The epidermis displays the best characteristics in this respect. The main lipids in this layer are cholesterol, fatty acids (FAs) and ceramides. FAs can occur in free form and as components of complex molecules. The most poorly characterized FAs are very long-chain fatty acids (VLCFAs) and ultra long-chain fatty acids (ULCFAs). VLCFAs and ULCFAs are among the main components of ceramides and are part of the free fatty acid (FFA) fraction. They are most abundant in the brain, liver, kidneys, and skin. VLCFAs and ULCFAs are responsible for the rigidity and impermeability of membranes, forming the mechanically and chemically strong outer layer of cell membranes. Any changes in the composition and length of the carbon chains of FAs result in a change in their melting point and therefore a change in membrane permeability. One of the factors causing a decrease in the amount of VLCFAs and ULCFAs is an improper diet. Another much more important factor is mutations in the genes which code proteins involved in the metabolism of VLCFAs and ULCFAs—regarding their elongation, their attachment to ceramides and their transformation. These mutations have their clinical consequences in the form of inborn errors in metabolism and neurodegenerative disorders, among others. Some of them are accompanied by skin symptoms such as ichthyosis and ichthyosiform erythroderma. In the following review, the structure of the skin is briefly characterized and the most important lipid components of the skin are presented. The focus is also on providing an overview of selected proteins involved in the metabolism of VLCFAs and ULCFAs in the skin.
The Western diet can lead to alterations in cardiac function and increase cardiovascular risk, which can be reproduced in animal models by implementing a high-fat diet (HFD). However, the mechanism of these alterations is not fully understood and may be dependent on alterations in heart lipid composition. The aim of this study was to evaluate the effect of an HFD on the fatty acid (FA) composition of total lipids, as well as of various lipid fractions in the heart, and on heart function. C57BL/6 mice were fed an HFD or standard laboratory diet. The FA composition of chow, serum, heart and skeletal muscle tissues was measured by gas chromatography–mass spectrometry. Cardiac function was evaluated by ultrasonography. Our results showed an unexpected increase in polyunsaturated FAs (PUFAs) and a significant decrease in monounsaturated FAs (MUFAs) in the heart tissue of mice fed the HFD. For comparison, no such effects were observed in skeletal muscle or serum samples. Furthermore, we found that the largest increase in PUFAs was in the sphingolipid fraction, whereas the largest decrease in MUFAs was in the phospholipid and sphingomyelin fractions. The hearts of mice fed an HFD had an increased content of triacylglycerols. Moreover, the HFD treatment altered aortic flow pattern. We did not find significant changes in heart mass or oxidative stress markers between mice fed the HFD and standard diet. The above results suggest that alterations in FA composition in the heart may contribute to deterioration of heart function. A possible mechanism of this phenomenon is the alteration of sphingolipids and phospholipids in the fatty acid profile, which may change the physical properties of these lipids. Since phospho- and sphingolipids are the major components of cell membranes, alterations in their structures in heart cells can result in changes in cell membrane properties.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.