INTRODUCTION
The epidermis has an obvious role of protecting us from the environment, but recent research is revealing some new functions. Keratinocytes have been shown to secrete oxytocin (OT) in response to an ATP analogue in a dose-dependent manner.1 Oxytocin is a neuropeptide which is involved with milk ejection, uterine contractions, behavior, memory, social bonding, and mental state.1,2,3,4 Oxytocin has also been shown to be involved with muscle regeneration, cardiovascular regulation, and osteocyte-adipocyte balance.4 In fact, both OT and its carrier protein neurophysin 1 are synthesized in keratinocytes.1
The oxytocin receptor (OTR) is a seven-membrane spanning receptor that is coupled via various G-protein isoforms to different signaling pathways, allowing it to have various physiologic functions in different cell types.2,5,6 The OTR is expressed on human fibroblasts.2,5 This receptor is internalized after binding with OT and is transported to the cell nucleus.5 Once in the cell nucleus, OT effects gene regulation.
Oxytocin binding to its receptor on fibroblasts has been shown to suppress senescence-associated secretory phenotype (SASP).4 When not suppressed, SASP promotes a low-level chronic inflammatory state by releasing proinflammatory cytokines such as interleukin (IL)-6, IL-1, chemokines, growth factors, and extracellular matrix-remodeling proteases.4 This leads to aging of the skin. Therefore, OT binding would have a protective, anti-inflammatory effect through its suppression of SASP and in turn its prevention of inflammatory cytokine release.4
This study attempts to establish a link between OT levels and clinical evaluation of the skin. Of interest, is whether or not a higher OT level correlates to more youthful appearing skin. Knowing that the appearance of the skin is not only due to intrinsic factors, we also evaluated the amount of lifetime sun exposure for each study subject as an indication of the amount of extrinsic or environmental aging.
The oxytocin receptor (OTR) is a seven-membrane spanning receptor that is coupled via various G-protein isoforms to different signaling pathways, allowing it to have various physiologic functions in different cell types.2,5,6 The OTR is expressed on human fibroblasts.2,5 This receptor is internalized after binding with OT and is transported to the cell nucleus.5 Once in the cell nucleus, OT effects gene regulation.
Oxytocin binding to its receptor on fibroblasts has been shown to suppress senescence-associated secretory phenotype (SASP).4 When not suppressed, SASP promotes a low-level chronic inflammatory state by releasing proinflammatory cytokines such as interleukin (IL)-6, IL-1, chemokines, growth factors, and extracellular matrix-remodeling proteases.4 This leads to aging of the skin. Therefore, OT binding would have a protective, anti-inflammatory effect through its suppression of SASP and in turn its prevention of inflammatory cytokine release.4
This study attempts to establish a link between OT levels and clinical evaluation of the skin. Of interest, is whether or not a higher OT level correlates to more youthful appearing skin. Knowing that the appearance of the skin is not only due to intrinsic factors, we also evaluated the amount of lifetime sun exposure for each study subject as an indication of the amount of extrinsic or environmental aging.
METHODS
A chart review was performed in an IRB-exempt study, revealing six female subjects aged 48–61 years old who qualified to be included. All were average BMI and non-smokers. Fitzpatrick skin types II–IV were included. Exclusionary criteria included any cosmetic procedures such as neurotoxin injections, dermal filler injections, chemical peels, laser treatments, or any other
