IL-6 Stimulates but is not essential for stratum corneum formation and permeability barrier development during gestation

Epidermal Dysfunction Leads to an Age-Associated Increase in Levels of Serum Inflammatory Cytokines

Even though elderly populations lack visible or other clinical signs of inflammation, their serum cytokine and C-reactive protein levels typically are elevated. However, the origin of age-associated systemic inflammation is unknown. Our previous studies showed that abnormalities in epidermal function provoke cutaneous inflammation, and because intrinsically aged skin displays compromised permeability barrier homeostasis and reduced stratum corneum hydration, we hypothesized here that epidermal dysfunction could contribute to the elevations in serum cytokines in the elderly. Our results show first that acute disruption of the epidermal permeability barrier in young mice leads not only to a rapid increase in cutaneous cytokine mRNA expression but also an increase in serum cytokine levels. Second, cytokine levels in both the skin and serum increase in otherwise normal, aged mice (>12 months). Third, expression of tumor necrosis factor-α and amyloid A mRNA levels increased in the epidermis, but not in the liver, in parallel with a significant elevation in serum levels of cytokines. Fourth, disruption of the permeability barrier induced similar elevations in epidermal and serum cytokine levels in normal and athymic mice, suggesting that T cells play a negligible role in the elevations in cutaneous and serum inflammatory cytokines induced by epidermal dysfunction. Fifth, correction of epidermal function significantly reduced cytokine levels not only in the skin but also in the serum of aged mice. Together, these results indicate that the sustained abnormalities in epidermal function in chronologically aged skin contribute to the elevated serum levels of inflammatory cytokines, potentially predisposing the elderly to the subsequent development or exacerbation of chronic inflammatory disorders.

Newborn skin care

Many organ systems undergo significant and rapid changes during the transition from an intrauterine to an extrauterine environment, especially those which serve as interfaces between the infant and the external environment. Historically the skin care methods employed during and after this period of rapid physiologic change have been derived from individual anecdotal experience or cultural tradition, rather than evidence-based or pathomechanistically derived data. While research in this area has historically been limited, it is increasing in scope and volume, and recent work has shed light on the changes experienced by the cutaneous organ during this period of transition. This increased understanding has driven new recommendations in skin care protocols for newborn infants and neonates.