Are epidermal stem cells unique with respect to aging?

Abstract

Epidermal stem cells are a population of somatic stem cells responsible for maintaining and repairing the epidermis of the skin. A malfunctioning epidermal stem cell compartment results in loss of the epidermis and death of the whole organism. Since the epidermis continually renews itself by sloughing a layer of cells every day, it is in a constant state of cellular turnover and requires continual cell replacement for life. Thus, maintaining a pristine epidermal stem cell population is of prime importance, even during aging. Unlike stem cells from internal tissues, epidermal stem cells show little response to aging. They do not appear to decrease in number or functionality with age, and do not show changes in gene expression, developmental responsiveness, or age-associated increases of reactive oxygen species. Thus, epidermal stem cells may be a unique somatic stem cell.

Stratum basale keratinocyte expression of the cell-surface glycoprotein CDCP1 during epidermogenesis and its role in keratinocyte migration

“…Epidermogenesis is a crucial step in skin regeneration and wound healing resulting in the formation of a new epidermal layer 35 . An important process in epidermogenesis is the constant shedding and sloughing off of the stratum corneum at the cellular surface, which stimulates the process of basal cell proliferation and thus epidermal renewal 38 . The restricted location of CDCP1 to the stratum basale indicates its possible involvement in the regulation of the cell migration necessary for epidermal renewal.…”

Characteristics of the Aging Skin

“…Moreover, within these epidermal stem cells, there is no evidence of changes in gene expression or developmental responsiveness or of any buildup of the ROS that contribute substantially to cellular degeneration. 33 Further characterization of these cells, particularly with regard to acquiring a comprehensive of the molecular and cellular components of their unique resistance to aging, could greatly facilitate further therapies for aging skin.…”

Cell-Extracellular Matrix Interactions in Normal and Diseased Skin

“…Although the epidermal stem cell compartment does not show evidence of major depletion, there is a reduction in b1 integrin expression and, in human skin, a flattening of the boundary between epidermis and dermis (Bosset et al 2003;Makrantonaki and Zouboulis 2007;Giangreco et al 2008Giangreco et al , 2010Racila and Bickenbach 2009). Given the non-cell-autonomous roles of integrins, one can speculate that reduced epidermal integrin levels may affect other cell compartments, such as skin vasculature and pigmentation.…”