Age-Related Changes in Sebaceous Wax Ester Secretion Rates in Men and Women

Jacobsen, Ellen; Billings, Julie K.; Frantz, Rita A.; Kinney, Carolyn K.; Stewart, Mary Ellen; Downing, Donald T.

doi:10.1111/1523-1747.ep12277224

Cited by 133 publications

(82 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Age and sex related differences have been reported in wax ester synthesis, which also correlates with total sebum output and activity. [30][31][32] In nature, waxes act as protective layers for leaves and fruits of plants, or skin, feathers and fur of animals. Additionally waxes are also found to coat bacteria, algae and fungi.…”

Section: Sebaceous Lipidsmentioning

confidence: 99%

Epidermal surface lipids

Pappas

2009

Dermato-Endocrinology

270

222

View full text Add to dashboard Cite

A layer of lipids, which are of both sebaceous and keratinocyte origin, covers the surface of the skin. The apparent composition of surface lipids varies depending on the selected method of sampling. Lipids produced by the epidermal cells are an insignificant fraction of the total extractable surface lipid on areas rich in sebaceous glands. Due to the holocrine activity of the sebaceous gland, its product of secretion (sebum) is eventually released to the surface of the skin and coats the fur as well. Lipids of epidermal origin fill the spaces between the cells, like mortar or cement. The sebaceous lipids are primarily non polar lipids as triglycerides, wax esters and squalene, while epidermal lipids are a mixture of ceramides, free fatty acids and cholesterol. The composition of the sebaceous lipids is unique and intriguing and elevated sebum excretion is a major factor involved in the pathophysiology of acne. Recent studies have elucidated the roles that epidermal surface lipids have on normal skin functions and acne. IntroductionThe sebaceous gland is now considered to be an important endocrine organ. The holocrine eruption of the sebaceous cells results in the secretion and release of sebum, which eventually coats the surface of the skin and the fur. The majority of the epidermal surface lipids are in fact of sebaceous origin while the lipids produced by the epidermis are an insignificant fraction of the total extractable surface lipid. 1 That is more apparent on areas rich in sebaceous glands, where the epidermal origin lipids average between 5 to 10 μg per sq cm, compared with average recoveries of 150 to 300 μg of sebum per sq cm from the forehead. Since this chapter is part of a sebaceous forum, the focus will include both classes of lipids on the surface of the skin. In addition, areas rich in sebaceous glands are the areas that acne lesions are manifested.Human sebum is a mixture of non-polar lipids, mainly triglycerides, wax esters, squalene, fatty acids and smaller amounts of cholesterol, cholesterol esters and diglycerides. [2][3][4][5] On the other hand, lipids produced by keratinocytes are a mixture of almost equal proportions of free fatty acids, cholesterol and ceramides. 6 Figure 1 shows the representative structures of the various lipid classes of epidermal surface lipids. Sebaceous LipidsThe sebaceous lipids are unique and intriguing. According to Nicolaides: 7 "two key words characterize the uniqueness of skin lipids: complexity and perversity". The relative composition of sebum depends on the sampling method used. In particular, if the major components of sebum, triglycerides, are sampled before or after their modification by bacteria, which hydrolyze them to free fatty acids and glycerol. [7][8][9][10][11] The mean weight % that is often cited in the literature is given in Table 1.Interestingly, human sebaceous lipids are significantly different in quantity and quality from sebaceous lipids of other species. [12][13][14] The reason for such a unique sebum composition is not understood; how...

show abstract

Section: Sebaceous Lipidsmentioning

confidence: 99%

Epidermal surface lipids

Pappas

2009

Dermato-Endocrinology

270

222

View full text Add to dashboard Cite

show abstract

“…Skin oiliness is caused by increased sebum production that declines with age [41], in women it falls by 40% by the age of 60 [42]. Sebum is composed of squalene, wax monoesters, triglycerides, cholesterol and cholesterol esters [43], and its production is primarily influenced by androgens [44] but also environmental factors like season, relative humidity and temperature [45] and the phase of the menstrual cycle [46].…”

Section: Increased Sebum Productionmentioning

confidence: 99%

Expert opinion and review article: The timing of comedone extraction in the treatment of premenstrual acne – a proposed therapeutic approach

Steventon¹

2010

Intern J of Cosmetic Sci

View full text Add to dashboard Cite

Synopsis The face is the most exposed part of our body, and deterioration of facial appearance, through disease or ageing, causes psychological distress. Acne lesions and subsequent pigmentation changes contribute to the unevenness of skin colour that is detrimental to facial attractiveness and leads to rejection and stigmatization in our society. The purpose of this review is to look at the root causes of premenstrual acne and, for the first time ever, propose that the specific timing of treatment can, at least in part, resolve the acne lesions. We postulate that it is the timing of the manual extraction that matters in resolving premenstrual acne and that the effectiveness of this therapy could be improved. Based on the reviewed evidence, we propose that it is important to remove the comedones at the time of ovulation, prior to the reduction of the size of the sebaceous orifice and epidermal barrier function, to counteract the onset of increased sebum production, prevent blockage of the pores and subsequent bacterial colonization and inflammation. If performed successfully, the extraction may contribute to a reduction in inflamed acne lesions and thus benefit women by increasing their facial attractiveness, well‐being, social function and thereby decrease psychological stress.

show abstract

“…Found throughout the domains of life, WEs have both functional and structural roles (12)(13)(14)(15). In some oleaginous bacteria, WEs are primarily used to store energy (16,17).…”

mentioning

confidence: 99%

A Fatty Acyl Coenzyme A Reductase Promotes Wax Ester Accumulation in Rhodococcus jostii RHA1

Round

Roccor

et al. 2017

Appl Environ Microbiol

View full text Add to dashboard Cite

Many rhodococci are oleaginous and, as such, have considerable potential for the sustainable production of lipid-based commodity chemicals. Herein, we demonstrated that Rhodococcus jostii RHA1, a soil bacterium that catabolizes a wide range of organic compounds, produced wax esters (WEs) up to 0.0002% of its cellular dry weight during exponential growth on glucose. These WEs were fully saturated and contained primarily 31 to 34 carbon atoms. Moreover, they were present at higher levels during exponential growth than under lipid-accumulating conditions. Bioinformatics analyses revealed that RHA1 contains a gene encoding a putative fatty acyl coenzyme A (acyl-CoA) reductase (FcrA). The purified enzyme catalyzed the NADPH-dependent transformation of stearoyl-CoA to stearyl alcohol with a specific activity of 45 Ϯ 3 nmol/mg · min and dodecanal to dodecanol with a specific activity of 5,300 Ϯ 300 nmol/mg · min. Deletion of fcrA did not affect WE accumulation when grown in either carbon-or nitrogen-limited medium. However, the ΔfcrA mutant accumulated less than 20% of the amount of WEs as the wild-type strain under conditions of nitric oxide stress. A strain of RHA1 overproducing FcrA accumulated WEs to ϳ13% cellular dry weight under lipid-accumulating conditions, and their acyl moieties had longer average chain lengths than those in wild-type cells (C 17 versus C 16 ). The results provide insight into the biosynthesis of WEs in rhodococci and facilitate the development of this genus for the production of highvalue neutral lipids. IMPORTANCE Among the best-studied oleaginous bacteria, rhodococci have considerable potential for the sustainable production of lipid-based commodity chemicals, such as wax esters. However, many aspects of lipid synthesis in these bacteria are poorly understood. The current study identifies a key enzyme in wax ester synthesis in rhodococci and exploits it to significantly improve the yield of wax esters in bacteria. In so doing, this work contributes to the development of novel bioprocesses for an important class of oleochemicals that may ultimately allow us to phase out their unsustainable production from sources such as petroleum and palm oil.KEYWORDS fatty acyl-CoA reductase, lipid accumulation, Rhodococcus, wax esters, metabolic engineering M any bacterial species, particularly the mycolic acid-producing Actinobacteria, synthesize neutral lipids for energy storage. For example, the soil bacterium Rhodococcus jostii RHA1 (referred to as RHA1 here) accumulates neutral lipids up to 70% of cellular dry weight (CDW) in response to environmental stresses, such as nitrogen limitation (1-3). These neutral lipids are primarily triacylglycerides (TAGs) and are stored in lipid bodies within the cytoplasm (4). Proteins associated with these carbon storage organelles (5) facilitate the dynamic shuffling of lipids between utilization and storage, allowing the bacterium to sequester intracellular energy reserves as needed. Due in

show abstract

Age-Related Changes in Sebaceous Wax Ester Secretion Rates in Men and Women

Cited by 133 publications

References 8 publications

Epidermal surface lipids

Epidermal surface lipids

Expert opinion and review article: The timing of comedone extraction in the treatment of premenstrual acne – a proposed therapeutic approach

A Fatty Acyl Coenzyme A Reductase Promotes Wax Ester Accumulation in Rhodococcus jostii RHA1

Contact Info

Product

Resources

About