Skin Training 2

7/30/2019 Skin Training 2

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SKIN CARE

TRAINING

Alain KHAIAT, Ph. D.Vice President R&D Asia Pacific


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TRAINING CONTENT

Skin physiology Cosmetic functions:

mechanism

ingredients used

performance assessment


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Skin

Is the external barrier of the body, both

physical and immunological

Is the mirror of the state of health of thebody

Skin plays an essential role both in the

aesthetic and health field.


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SKIN PHYSIOLOGY

The skin is the outer most layer of the body. It

is constituted of 2 layers :

epidermis

dermis

which sit on the fat layer around the muscles.


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EPIDERMIS

The stratum corneum made essentially of

dead cells is exfoliating.

The space between the cells constitutes theintercellular cement.


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DERMIS

The dermis is where the collagen and elastin

fibers are. These fibers are responsible for

the skin structure and elasticity.They are degraded by enzymes called

collagenase and elastase which belong to

the class of Matrix Metallo Proteases orMMP.


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OIL PRODUCTION

Oil is produced in the sebaceous gland ,

production is stimulated by hormones

Oil flows into the hair follicle then onto the

skin surface


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Oil Production

Normal hair follicle where sebum empties onto skin surfacethrough follicle opening


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COMEDONES

Whiteheads are closed comedones. Theobstructed follicle prevents oil flow andprovides an oil reservoir for bacterial

growth. They lead to inflammation Blackheads are open comedones (follicle

obstruction). The color is melanin and

oxidized lipids, not dirt. The content is firmand dilates the follicle, blackheads are notinflammatory


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COMEDONESWhiteheadsor closed comedones

stays beneath the skin. Slightly raised, lightcoloured lesion

Caused by build up of debris ( cells + sebum)

within follicle

Blackheads oropen comedones

a whitehead becomes a blackhead when

it enlarges until a dark plug protrudes through

the skin surface

* Both whiteheads and blackheads may stay

on the skin for a long time.

* Whiteheads and Blackheads are non-

inflammatory


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SOLAR SPECTRUM


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UVB DAMAGE

UVB impact on DNA in the cell creating

damages which may lead to cancer

P53 gene codes for a protein that allowsrepair of the DNA or kill the cell if repair is

not possible: sunburn cells


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UVA DAMAGE

UVA acts through an oxidative stress,

forming free radicals (reactive oxygen

species) that will damage the DNA Reactive oxygen species create damages

leading to cancer

Pigment production is the defensemechanism


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TRAINING CONTENT

Skin physiology

Cosmetic functions: mechanism

ingredients used

performance assessment


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COSMETICS

DEFINITION :

Products applied on the skin, hair, teeth or

teguments in order to : beautify

perfume

cleanse

promote attractiveness

alter the appearance


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COSMETICS : FUNCTIONS

Cleansing

Moisturizing

UV protection

Aging - Wrinkle

Acne & Oily skin

Pigmentation


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CLEANSING

Soap : high pH, low rinsability, high

irritation

Some soap have high rinsability, low irritation

Cream cleanser / Facial wash :

rinse off : detergent-based, neutral pH,

irritation depends on detergent type andconcentration

tissue off : leave on, emulsion-based, less

fresh clean feel


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RINSABILITY

Measured by Fourrier Transform Infra Red

or FTIR : scanning of the skin before

application and after rinsing of a cleanser.The difference is representative of the

quantity of product left on the skin.

Digital imaging with proper light allowsalso to evaluate rinsability


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IRRITATION

Patch test

Chromameter (red color)

Trans epidermal water loss : TEWL


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CLEANSER FORMULA

A typical cleanser formula consists of :

detergent 10 - 15 %

foam booster 0 - 2%

preservative < 1 %

fragrance 0 - 1%

water Qs 100 %


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CLEANSER FORMULA

Surfactants : usually combinations are used to

enhance lathering and reduce irritation. SLS is to

be avoided, it strips the skin of its lipids

contributing to irritation. Preservatives : allergy potential of formaldehyde

donors.

Fragrance : known allergens (like Peru BalsamorMuskAmbrette)have been banned. It is important

for the fragrance to meet IFRA guidelines


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MOISTURIZING

Water, like air or light, is essential to life

Moisturization is a womans main

expectation from a cosmetic product

Dermatologists face dry skin condition

every day : physiological, pathological(ichthyosis), therapeutic (PUVA, retinoids)


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WHERE IS THE WATER ?

50% is intracellular

15% is extracellular

5% is plasmatic

30% is in the sweat glands


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MECHANISMS OF REGULATION

Hydration through deeper layers

Loss through evaporation

Moisture retaining ability of the stratum

corneum,dependent on :

Hydro Lipido Proteic film (HLP)

Natural Moisturizing Factor (NMF)

integrity of intercellular cement


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HLP FILM

Originates from sebum and sweat secretions

Composed of :

water - triglycerides ions - cholesterol free & esterified

amino acids - squalene

urea - fatty acids

- waxes


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NMF

Amino acids

Urocanic acid

Pyrollidone carboxylic acid : PCA

Electrolytes

Sugars


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INTERCELLULAR CEMENT

Ceramides ( sphingolipides )

Fatty acids ( Linoleic acid )

Cholesterol ( free & esters )


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MOISTURIZING INGREDIENTS

Occlusive agents

Structural lipids

Hydrophilic film forming agents

Humectants

NMF

AHA


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OCCLUSIVE AGENTS

Vaseline, paraffin

Waxes of animal or plant origin

Some silicone oils or waxes

Some vegetable oil (sweet almond)

Some fatty esters (isopropyl myristate)

Fatty alcohols

older technique, often comedogenic


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STRUCTURAL LIPIDS

Essential Fatty Acids (EFA : linoleic,

linolenic acids)

Poly unsaturated fatty acids (PUFA : EPA,DHA)

Ceramides or pseudo ceramides

Cholesterol


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HYDROPHILIC FILM FORMING

AGENTS GAG : glycosaminoglycans like Hyaluronic

acid or chondroitin sulfates

Collagen

Proteins

Chitin or Chitosan


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HUMECTANTS

Glycerin

Propylene Glycol or Butylene Glycol

Sugars


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NMF

PCA

Urea (below 10 %)

Amino Acids or hydrolyzed protein


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AHA

At low concentration (< 2 % ) AHA are

moisturizing agents by creating hydrogen

bonds between the protein chains.The most common are :

glycolic acid

lactic acid citric acid

malic acid


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PERFORMANCE ASSESSMENT

FTIR :the ratio of amide I to amide II peaks is

function of the skin hydration

NMR : nuclear magnetic resonance

TEWL : trans epidermal water loss

Capacitance (Corneometer)

Conductance (Skicon)


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FORMULATION

Typically they are oil in water emulsions :

water

propylene glycol : penetration enhancer itbecomes irritating above 5%

humectants, film forming agents, AHA, NMF

emulsifiers : could contribute to irritation,concentration to be kept to a minimum

oils, fatty esters : some are comedogenic


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UV PROTECTION

Two types of filters are used :

chemical

mineral


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SOLAR SPECTRUM


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CHEMICAL FILTERS

Limited spectrum, highly regulated

Most common filters :

cinnamates (UVB)

PABA (UVB)

Oxybenzone (UVA)

Avobenzone (UVA)


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MINERAL FILTERS

Broad spectrum, filtering capacity function

of size, influence on product texture

Most common filters : TiO2

ZnO


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PERFORMANCE ASSESSEMENT

SPF measurement in vivo: it is the ratio of

the minimum erythemal dose with and

without protection ( relates only to UVBprotection )

in vitromeasurements :

Diffey method spectrophotometric absorption method


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AGING : INTRINSIC

Program theory : each cell contains a clock

which control the number of multiplication

Error theory : occurrence of errors in thereplication which eventually lead to cell

death

Control theory : cells function is remotelycontrolled by secretions ( hormones )


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AGING : EXTRINSIC

Sun : UVA / UVB / IR

Psycho social factors : overwork, stress

Dietary factors : insufficient water supply,vitamin deficiency, alcohol, smoking

Iatrogenic factors : corticosteroids,

ionizing radiation, diuretics Pathological factors : genodermatose,

acrogenia

Hormonal factor : menopause


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MANIFESTATIONS OF SKIN AGING

Epidermis :

reduction in cell renewal rate

thickening of stratum corneum decrease in barrier efficiency : increase in

TEWL and hyperkeratosis

ridges are flattened out and intercellular

spaces enlarged

pigmentation problems : actinic lentigines

decrease in skin immune system


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MANIFESTATIONS OF SKIN AGING

Sebaceous glands :

reduction in sebum secretion (hormones

influenced) Sweat glands :

less active

HLP film : thinning of film means less protective barrier


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MANIFESTATION OF SKIN AGING

Dermis :

destruction of collagen and elastin fibers

network proteoglycans and glycoproteins are reduced

increase in elastin synthesis : elastosis


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WRINKLES

Expression lines :

they are the first manifestation

due to constant creasing of the face accentuated by environmental factors

they appear around the eyes (crows feet), the

nose and mouth (naso-labial fold), forehead(frown lines)


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WRINKLES

Gravity lines :

skin and muscle structure become slack and

droops downwards subcutaneous tissues tend to sag

flabby cheeks, double chin, bags under the

eyes and drooping eyelids


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WRINKLES

Elastosis wrinkles :

due to UV radiation, the epidermis is injured

(free radicals), the fibroblasts in the dermisare over-active and abnormal deposits of

elastin occur


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ANTI AGING : PREVENTION

Protective agents :

sun protection

anti free radicals : SOD, Se, Si, Vit. E, Vit. C,carotenoids, flavonoids, -orizanol

Nourishing agents

vitamins : A (esters), B5 (panthenol), C, E, EFA(linoleic & linolenic acids), PUFA


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ANTI AGE : PREVENTION

Moisturizing agents

Metabolism activators :

unsaponifiable lipids (phytosterols)

plant extracts (Centella asiatica, Ginseng)

microalgae extracts

Bacteria, fungal or yeast extracts


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ANTI AGING : PREVENTION

Conditioning agents :

anti MMP (elastase, collagenase)

hyaluronic acid collagen, elastin (hydrolyzed)

nucleic acids (DNA, RNA)


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ANTI AGING : REPARATION

Retinol : transformed into the skin inretinoic acid, it has its positive propertieswithout the irritation

AHAs work by reducing the corneocytescohesion, increasing desquamation (cellrenewal), hydration and plasticity

Vitamin C

micro circulation activators : plant extracts


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PERFORMANCE ASSESSMENT

Cutaneous relief :

imprint techniques : micro depressionary

network, profilometry macrophotography : visible, UV light

confocal microscopy

biopsy Cell renewal :

use of a dye : danzyl chloride or dihydroxy

acetone (DHA)


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PERFORMANCE ASSESSEMENT

Alternative methods :

used to determine the activity of ingredients

on molecules, cell cultures or skin replica Physiological parameters :

hydration

elasticity : cutometry, twistometry,balistometry

pigmentation : photography, chromameter

vascularisation : Laser Doppler Velocimetry


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COSMETIC ACNE: from physiology

to treatment


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ACNE

95% of the population is affected at one

time or another by ACNE

ACNE affects 85% of the teenagers: 10% require medical attention: severe acne

with 1% difficult to treat

90% have mild acne or cosmetic acne


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Puberty : period over which thesecondary sexual characters gradually

become manifest as the reproductive

system develops to full capacity and

there is rapid somatic growth.


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Onset of puberty in girls

Breast development following the increase

of estrogen from the ovaries

Menstruation


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Puberty and Adolescence

Adolescence is a difficult period for most

people: period of changes

Herd bonding & sexual involvement

Adolescence is a particularly bad time to

have skin problems, especially on the faceor on the extremities

Physiological changes in the


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Physiological changes in theskin during puberty and

adolescence

Increase in sebum production: oily skinand hair

Onset of "body odor"

Anguish in young men when male-patternbalding begins in the teenage years


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Ideal skin for girls

Skin should be oil-free with no pimples or spots

Plenty of hair on head, but none on face, under thearms or on the legs

puberty makes this ideal image virtually

impossible to achieve


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Acne vulgaris (Pimples)


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Acne : a disorder of the pilosebaceous

unit, occurs in both sexes but is more

distressing to the women, not only

because of the cosmetic effect but

because of the frequent permanent

scarring


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ACNE

Normal hair follicle where sebum empties onto skin surfacethrough follicle opening


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Classification of acne

Non-inflammatory lesions: open & closed

comedones

Inflammatory lesions: papules, pustules,

nodules, cysts


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Pathogenesis of acne

Sebaceous glands hyper-activity

Pilosebaceous duct obstruction

Bacterial colonization and inflammation


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Increases sebum secretion

The cause of acne (1)

The effect of Androgen hormones

Im Androgen

Hyperkeratinization


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The cause of acne (2)

The effect of Propionobacterium acnes

We love

sebum Hydrolyzes sebum

Free fatty acids

Inflammatory acne


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ACNE TREATMENT

Drugs

Dermatological Procedures

Cosmetics

and/or

Squeeze the pimple


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DERMATOLOGICAL PROCEDURE

Peeling with drying and keratolytic agents : sulfur,

salicylic acid, resorcinol, benzoyl peroxide


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COSMETICS

Traditionally the anti-acne approach has

used drying keratolytic ingredients:

Benzoyl peroxide (5 or 10%) Salicylic acid (0.5 or 2%)

Sulfur (~2%)


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OILY SKIN

Ingredients usually used to reduce shine :

clay (bentonite)

talc Kaolin

These ingredients will increase oil production

Ingredients used to control oil secretion: Soy/Wheat protein

Cedarwood


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OILY SKIN

Efficacy is measured by :

Sebumeter : measure of the absorbance

of a tape Sebutape

removal of lipids and determination of

quantity


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PIGMENTATION

Melanins are the result of the

transformation of Tyrosine into DOPA then

Dopaquinone by Tyrosinase in themelanocyte.

Melanins are transferred from the

melanocyte to the keratinocyte layers

Pigmentation Formation Mechanism


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Tyrosinase

KERATINOCYTE

(Epidermis)

MELANOCYTE

(Basal Layer)

Tyrosine Melanin

Dermis

UVIrritation

Inflammatory Response

Hormone3

1

2

Melanosome

FIBROBLAST

Variety of Causes

Variety of Responses


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PIGMENTATION

Ingredients used to decrease pigmentation :

hydroquinone : effective but not safe

ascorbic acid derivatives plant extracts : Kojic acid, arbutin, Licorice,

Centella, Bayberryextract

Except for Hydroquinone, the skin lighteningeffect is only visible after several weeks.


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PIGMENTATION

Efficacy is measured by :

Chromameter : L measure

Mexameter : evaluation of melanin andredness

Photography : visible, UV with data analysis


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