| FUTURISTIC APPROACHES TO SKIN CARE | arTicle
to skin care: stem cells, genes and topical treatment
Futuristic approacHes
NEIL S. SADICK MD., F.A.A.D., F.A.A.C.S., F.A.C.P.,
F.A.C.PH. is a Clinical Professor of Dermatology at Weill Cornell Medical College in New York, New York, U.S.A. He is also the clinical director and founder of Sadick Dermatology and Sadick Research Group, New York, New York, U.S.A. His multiple discoveries have strongly influenced and transformed the future of dermatology.’
Neil S. Sadick describes how a formulation enriched with biopeptides improves multiple signs of skin ageing
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his arTicle begins by inTroducing epidermal stem cells and discussing concepts that relate to stem cells and ageing. The article then goes on to review scientific methods in the development of products to combat ageing and cellulite.
specific topics covered include cell longevity genes; anti- ageing by gene modulation; and topical treatment of cellulite with a retinol, caffeine and ruscogenine combination.
Stem cells Embryonic stem cells can differentiate into all types of cells or they can divide many times without differentiating. Like embryonic stem cells, adult stem cells can renew themselves and divide many times, but they can give rise to only several cell types. Adult stem cells retain their high capacity for renewing themselves throughout adult life, and they can usually produce daughter cells, called transit amplifying (TA) cells, that undergo terminal differentiation (1,2). Adult stem cells are found in animal tissues whose
cells must be replaced by continual cell division. In such tissues, which include epithelial cells of the skin, cells are replaced not by proliferation of fully differentiated cells, but by replication of the less differentiated stem cells. Stem cells can divide symmetrically to produce two identical daughter cells or asymmetrically to produce an identical stem cell or a more differentiated TA cell (3). In
this way, stem cells provide a source of differentiated cells throughout the life of the organism. The destiny of a stem cell is determined by the
intercellular signals of its environment. Adult stem cells are surrounded by “niche” cells that shelter the stem cells from stimuli for differentiation, apoptosis, and other activities that would compromise stem cell reserves (4). Niche cells also protect stem cells against uncontrolled production that could lead to malignancy (3).
Epidermal stem cells Epidermal stem cells maintain tissue homeostasis and repair injured tissue (5). Homeostasis is maintained by replication of keratinocytes (derived from stem cells) in the basal layer attached to the basement membrane. A stem cell in the basal layer divides asymmetrically to produce an identical stem cell and a TA cell. Daughter cells of the TA cell undergo terminal differentiation and divide only about five times (3). As the TA cells differentiate and stratify, they detach from the basement membrane and progress upward to the spinous layer, the granular layer, and finally to the stratum corneum (5). These three epidermal cell layers represent early versus late stages of differentiation (6). Stratum corneum cells are constantly shed from the skin surface and must be replaced by differentiating cells from below (1,5). The epidermis, hair follicles, and sebaceous glands each have distinct stem cells that can renew themselves, generate all cell types in their resident tissue, and maintain homeostasis in their tissues (7).
email nssderm@
sadickdermatology.com
KEYWORDS cosmeceutical, ageing, stem cell, gene modulation, sirtuin, SIRT1, ageing-responsible interface, ARI, cellulite, retinol, vitamin A, epidermis, caffeine, ruscogenine
like
embryonic stem cells, adult stem cells can renew themselves and divide many times, but they can give rise to only several cell types.
prime-journal.com | March 2011 ❚ 23
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