Journal of Clinical & Experimental Dermatology Research
Open Access

The Connection between Scalp Dermal Aging and Hair Follicle Aging

Nicola Ruggiero^{* *}Correspondence: Nicola Ruggiero, Department of Plastic and Reconstructive Surgery, University of Naples Federico, Naples, Italy, Email:

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Description

The scalp consists of tissue layers that cover the cranium. It is an anatomic region bordered anteriorly by the face, and laterally and posteriorly by the neck. Scalp consists of 5 layers: the skin, connective tissue layer, galea aponeurotica, loose areolar connective tissue, and pericranium. The scalp is a physical barrier to guard the cranium against physical trauma and potential pathogens that may cause infection. Hair grows on the skin of the scalp not only aid in heat conservation however to plays a role in the appearance and sexual signaling. The primary layer is the skin, which is thick and contains hair follicles and sebaceous glands. The hair follicles will extend into the dense connective tissue layer, wherever the nerves, lymphatics, and also the vascular supply of the scalp reside [1]. It is firmly attached up to the connective tissue layer and serves to prevent stretching of the scalp, particularly throughout surgery, which prevents complications. The pericranium is the deepest layer of the scalp that's composed of dense irregular tissue. It contains the vascular supply that's very important to support the underlying calvarium.

Age-related structural and functional changes discovered in human skin are probably to be paralleled in sun-exposed scalp skin, despite the protection offered by the covering of terminal hair follicles. Structural changes, as well as cutting of the stratum, flattening of the epidermal-dermal basement membrane and related loss of the plexus ridges, additionally to changes within the composition of the papillary and latticed stratum. Having physically altered dermal surroundings that are a lot stiffer can ultimately impact the power of the follicle to move up and down throughout the remodelling section with every hair cycle [2]. With the structural changes inside the scalp dermal surroundings, a big range of age-related biochemical changes additionally occur. Transcriptomic analysis of Dissecting Folliculitis (DFs) derived from sun-protected, inguinal iliac skin of young. It is found that the foremost up-regulated genes in older fibroblasts are those attached to the immune reaction. A rise in the prevalence of inflammatory-associated fibroblasts in aging scalp skin with a magnified expression of proinflammatory genes and SASP can have a damaging impact on the anagen follicle.

Single-cell ribonucleic acid sequencing has shown that aged DFs undergo a considerable decrease in their interactions with alternative skin cell varieties. The reduced interaction with uniform bulb matrix keratinocytes will undoubtedly impact on the maintenance of the anagen follicle. Since dermal sheath cells migrate into the stratum during wound healing, chronic unresolved inflammation related to dermal scalp aging could induce evacuation of follicular dermal sheath cells into the dermal surroundings, and exploit the follicle with an aged phenotype [3,4]. It is vital to recollect that hair aging is very variable in terms of quality, lifestyle, genetic predisposition and graphical location, that all impact the hair type (ie diameter, density, colour, durability, and curl). Some individuals face early onset greying, and a few women face hair thinning/ loss earlier than others, again this might be the result of environmental or genetic factors. Sporadic washing, sun exposure, pollution and gas exposure will increase aerobic stress in scalp skin due to oxidation of lipids and squalene within the sebum [5]. Sebum secretion encompasses squalene, triglycerides, wax and steroid esters, and also the product of carboxylic acid breakdown and coats the hair fibre and surface of the skin. These lipids play a vital role within the normal functioning of the skin barrier, however, they're additionally liable to external stressors since pollution and ultraviolet will cause peroxidation of lipids and squalene.

Magnified exposure to ground ozone will increase macromolecule peroxidation and protein oxidation, depleting antioxidants within the corneum. These lipids will become oxidized by pollution ozone and ultraviolet, inflicting aerobic stress and inflammation on the scalp. However this impact on the follicle is unclear, but squalene monohydroperoxide (peroxidized squalene) induces hyperproliferation and inflammation in an exceeding keratinocyte cell line and colocalizes with the aerobic stress marker malondialdehyde in scalp dandruff. This might be important for the follicle, as murine studies found lipid peroxidation induced apoptosis in follicle cells leading to early-onset catagen.

References

1. Alster Serris A, Snippert HJ, Haegebarth A, Kasper M. Lgr6 marks stem cells in the hair follicle that generate all cell lineages of the skin. Science. 2010;327(5971): 1385-1389.

   [CrossRef] [Google Scholar] [PubMed]

2. Gurtner GC, Werner S, Barrandon Y, Longaker MT. Wound repair and regeneration. Nature. 2008;453(7193): 314-321.

   [CrossRef] [Google Scholar] [PubMed]

3. Hsu YC, Li L, Fuchs E. Emerging interactions between skin stem cells and their niches. Nat Med. 2014;20(8): 847-856.

   [CrossRef] [Google Scholar] [PubMed]

4. Ito M, Liu Y, Yang Z. Stem cells in the hair follicle bulge contribute to wound repair but not to homeostasis of the epidermis. Nat Med. 2005;11(12): 1351-1354.

   [CrossRef] [Google Scholar] [PubMed]

5. Harding KG, Morris HL, Patel GK. Science, medicine and the future: healing chronic wounds. BMJ. 2002;324(7330): 160-163.

   [CrossRef] [Google Scholar] [PubMed]