Nouveautés dans la pathogenèse et le prévention du vieillissement cutanée d’origine extrinsèque (photovieillissement)(dermatohéliose)(pour les professionnels)

What’s New In The Pathogenesis And Prevention Of Extrinsic Aging (Ageing) (Photoaging) (For Professionals)

Skin Aging can be Understood by considering two concepts

• Cumulative acute stress through chronic mechanisms: three stages

1. degeneration of macromolecules
2. Altered cell function
3. Modified Structure and function of organs

• Mt (mitochondrial) DNA mutation: increased oxidative stress generation

1. characterized4977 base pairs (bouble stranded)
2. deletion mutations cause premature ageing (Trifunovicz, Nature 2004: progeria in mice, Kujoth, Science)

• Concerning humans, our understanding of mt mitochondrial mutation is circumstancial

1. photoaged skin is characterized by increased mitochondrial DNA mutations
2. irradition in vitro and in in Vivo of fibroblasts with UV exposure

How does Reactive oxidative stress lead to skin ageing ? The team of the presenter used human unirradiated fibroblasts with mtDNA deletion mutation

1. these can be extracted from patients with Kearns-Sayre Syndrome: all the cells carry the deletion (ptosis is a symptom and the patients die before reaching  the age of 10)
2. increases ROS (Reactive Oxgen Species or Free Radicals) and lysyl oxidase enzyme levels initially

• Levels at which the changes occur

1. dermis: after 1-6 weeks: overexpression of MMP 1 and 2 and VEGF, decrease of TIMP-1: all of this increases collagen breakdown which correlates with wrinkles (destruction of picrosirius expression)
2. also epidermal atrophy: (immunohistochemical staining of KSS shows after 2 weeks that epidermis is thinner and stratified than normal counterparts): increase of filaggrin, increase in lipid enzymes (glkccer) and decrease of hbd-2 (antimicrobial peptase)

How to prevent and cure photoaging ?

• improvement of mitochondrial function and integrity-novel ingredients, revert symptoms of skin aging

• Concretely, Environmental factors play a role

1. Uv radiation by the sun
2. pollution: Ambient Particulate Matter (PM): air pollution=incomplete exhast fumes. Diesel engines (diesel) (Soot): increased risks of pigment spots=Epidemiological observation (Polyhydrocarbon particles attach to AhR which increases MMP-1 and melanin synthesis)

Contributors:

Dr Christophe HSU – dermatologist. Geneva, Switzerland

Krutmann J, Aging and Photoaging – 22nd World Congress of Dermatology (WCD) – Seoul, South Korea