Extrinsic ageing in the human skin is associated with alterations in the expression of hyaluronic acid and its metabolizing enzymes

Abstract

Extrinsic skin ageing or 'photoageing', as opposed to intrinsic skin ageing, is the result of exposure to external factors, mainly ultraviolet irradiation. Glycosaminoglycans (GAG) and particularly hyaluronic acid (HA) are major components of the cutaneous extracellular matrix involved in tissue repair. However, their involvement in extrinsic skin ageing remains elusive. In this study, we investigated the expression of HA and its metabolizing enzymes in photoexposed and photoprotected human skin tissue specimens, obtained from the same patient. Total GAG were isolated, characterized using specific GAG-degrading enzymes and separated by electrophoresis on cellulose acetate membranes and polyacrylamide gels. Quantitation of HA in total GAG was performed using ELISA. Gene expression of hyaluronan synthases (HAS), hyaluronidases (HYAL) and HA receptors CD44 and receptor for HA-mediated motility (RHAMM) was assessed by RT-PCR. We detected a significant increase in the expression of HA, of lower molecular mass, in photoexposed skin as compared with photoprotected skin. This increase was associated with a significant decrease in the expression of HAS1 and an increase in the expression of HYAL1-3. Furthermore, the expression of HA receptors CD44 and RHAMM was significantly downregulated in photoexposed as compared with photoprotected skin. These findings indicate that extrinsic skin ageing is characterized by distinct homoeostasis of HA. The elucidation of the role of HA homoeostasis in extrinsic skin ageing may offer an additional approach in handling cutaneous ageing.

Aging Skin: Nourishing from the Inside Out – Effects of Good Versus Poor Nitrogen Intake on Skin Health and Healing

“…Extrinsic skin aging is also characterized by a distinct homeostasis of HA [40]. Photo-exposed skin shows an increased amount of degraded (lower molecular weight) HA compared with the photo-protected skin, and this degradation is associated with an increase of hyaluronidases 1, 2, and 3 and with a decreased expression of HAS1.…”

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“…[31] HA is most abundant in the skin, [32][33][34][35][36] accounting for 50% of total body HA. [37] HA is mainly produced by mesenchymal cells but can also be produced by other cell types.…”

Estudo do revestimento de modelos de stents coronários biorreabsorvíveis de PLLA com PLDLA/PLGA e ácido hialurônico

“…Figura 3: Estrutura química do ácido hialurônico (Tzellos et al, 2009) O HA é um glicosaminoglicano que está relacionado diretamente à diversas funções, entre elas a adesão e migração de leucócitos nos tecidos conectivos, principalmente linfócitos-T, que são importantes mediadores da resposta imunológica. Assim, o HA pode ter um papel importante na função das células T e sua interação com outros tecidos, principalmente durante o processo inflamatório (Evanko et al, 2012;Tzellos et al, 2009).…”

“…Assim, o HA pode ter um papel importante na função das células T e sua interação com outros tecidos, principalmente durante o processo inflamatório (Evanko et al, 2012;Tzellos et al, 2009).…”

“…Figura 3: Estrutura química do ácido hialurônico (Tzellos et al, 2009). 16 PLGA superfície vidro esterilizada por UV; E) PLGA superfície ar esterilizada por plasma; F) PLGA superfície vidro esterilizada por plasma; G) PLGA-HA e H) PLGA-HAADH.…”