Thematic review series: Skin Lipids. Sebaceous gland lipids: friend or foe?

Abstract

Sebaceous glands are intriguing glands that are found throughout the human body except on the palms of the hands and soles of the feet. The true function of these glands has yet to be determined, but there are several theories, including antioxidant effects, antibacterial effects, and transport of pheromones. Sebaceous glands produce lipids that are involved in the pathogenesis of one of the most prevalent diseases of adolescence, acne. Although the majority of lipids produced by the sebaceous gland are also produced in other areas of the body, there are two that are characteristic of the sebaceous gland, wax esters and squalene.This review seeks to present an update on the physiology of the sebaceous glands, with particular emphasis on the production of sebaceous lipids.

Normal Fur Development and Sebum Production Depends on Fatty Acid 2-Hydroxylase Expression in Sebaceous Glands

“…These observations underline the importance of the SG in hair follicle homeostasis. The major function of SG is the production of sebum, which contains various lipids and is released into the hair canal by holocrine secretion (5,6). Sebum components have antimicrobial activity (33,34), and sebum is protective against oxidative stress and UVB (35,36).…”

“…For example, -hydroxylated ceramides covalently bound to proteins in the cornified envelope are essential components of the water barrier of the skin (4). The major fraction of the noncovalently bound skin surface lipids is derived from the sebum produced by SG and released by holocrine secretion (5,6). In general, sebum is deposited on the hair inside the follicle and is brought up to the surface of the skin along the hair shaft.…”

“…Sebum lubricates and protects the hair and skin and prevents drying and irritation of membranes. Sebum lipids possibly play a role in waterproofing, and antibacterial sebum lipids may inhibit infections of the skin (5). Significant species-specific differences in the sebum composition exist, but their functional relevance is largely unknown (7).…”

In vitro activity, extraction, separation and structure elucidation of antibiotic produced by Streptomyces anulatus NEAE-94 active against multidrug-resistant Staphylococcus aureus

“…Fatty acids are promising as antimicrobial agents in medicine and the food industry due to their safety, non-specific mode of action and the lack of resistance mechanisms against the actions of these fatty acids [26,27]. When S. aureus colonization occurs in the skin, human skin summons a battery of host-defence mechanisms responsible for natural protective immunity, which include fatty acids and antimicrobial peptides [28]. The most potent antibacterial fatty acid in mice is 9-hexadecenoic acid, and in humans, its isomer 6-hexadecenoic acid [29].…”

Sebaceous lipids are essential for water repulsion, protection against UVB-induced apoptosis, and ocular integrity in mice

“…The prototype sebocyte is found in hair follicle-associated sebaceous glands (SGs), that produce sebum consisting essentially of triglycerides, wax esters, squalene (in humans only) and free fatty acids (Smith and Thiboutot, 2008). Sebum is reported to be important for skin and hair coat waterproofing, and its antioxidative and antimicrobial properties have led to the assumption that it is also important to maintain the epidermal barrier (Hinde et al, 2013;Schneider and Paus, 2010;Tóth et al, 2011).…”