INDICATE ALTERATION OF THE SKIN BARRIER Pascale MILANI, Anna - - PowerPoint PPT Presentation

▶
indicate alteration of the skin barrier
SMART_READER_LITE
LIVE PREVIEW

INDICATE ALTERATION OF THE SKIN BARRIER Pascale MILANI, Anna - - PowerPoint PPT Presentation

Aug 28, 2023 21 likes •323 views

CORNEOCYTES NANO-MECHANICAL PROPERTIES CHANGES INDICATE ALTERATION OF THE SKIN BARRIER Pascale MILANI, Anna Drillat, Julien CHLASTA, Rawad ABDAYEM, Sanja KEZIC, and Marek HAFTEK Stratum corneum: an essential physical barrier Physical barrier

slide-1
SLIDE 1

CORNEOCYTES NANO-MECHANICAL PROPERTIES CHANGES INDICATE ALTERATION OF THE SKIN BARRIER

Pascale MILANI, Anna Drillat, Julien CHLASTA, Rawad ABDAYEM, Sanja KEZIC, and Marek HAFTEK

slide-2
SLIDE 2

Stratum corneum: an essential physical barrier

  • Physical barrier – mechanical resistance
  • Chemical barrier
  • Water barrier
  • Photoprotective barrier
  • …
slide-3
SLIDE 3

Stratum corneum: an essential physical barrier

Lipid envelope Cornified envelope Keratin & NMF Corneodesmosome

Mature Immature Desquamation

Intercellular lipids

slide-4
SLIDE 4

Evaluation of barrier condition in a minimally invasive manner

Tape stripping

+

Atomic force microscopy

slide-5
SLIDE 5

AFM operation

x y z

slide-6
SLIDE 6

AFM operation

slide-7
SLIDE 7

Evaluation of corneocytes mechanical properties

Milani et al, J. Mol. Rec. 2017

slide-8
SLIDE 8

Evaluation of corneocytes mechanical properties

20 40 60 80 100 120 140

Elastic Modulus (MPa) keratin fibers Cornified envelope Lipid envelope

*** *** 350 300 250 200 150 100 50

Ceramide Keratin filament NMF Involucrine Loricrine Transglutaminase

Milani et al, J. Mol. Rec. 2017

slide-9
SLIDE 9

Exploration of the maturation process

immature mature

L2 L7 L14

Stratum corneum

immature mature superficial profound L2 L7 L14

50 MPa 500 MPa

Lipid envelope Cornified envelope Keratin fibers

EXISTENCE OF DEPTH AND MATURATION-RELATED

MECHANICAL CHANGES WITHIN THE SC

Milani et al, J. Mol. Rec. 2017

slide-10
SLIDE 10

Exploration of the maturation process

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Relative stiffness N2 N7 N14

Cornified envelope Intracellular matrix

immature mature superficial profound Intracellular stiffness CE stiffness

THE RELATIVE STIFFNESS : AN INDICATION OF CORNEOCYTE MATURITY

Milani et al, J. Mol. Rec. 2017

slide-11
SLIDE 11

THE RELATIVE STIFFNESS : AN INDICATION OF CORNEOCYTE MATURITY

Exploration of the maturation process

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Relative stiffness N2 N7 N14

Cornified envelope Keratin fibers

immature mature superficial profound Intracellular stiffness

  • 1. Moisture gradient

Milani et al, J. Mol. Rec. 2017

slide-12
SLIDE 12

THE RELATIVE STIFFNESS : AN INDICATION OF CORNEOCYTE MATURITY

Exploration of the maturation process

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Relative stiffness N2 N7 N14

Cornified envelope Keratin fibers

immature mature superficial profound Intracellular stiffness

  • 1. Moisture gradient

Milani et al, J. Mol. Rec. 2017

slide-13
SLIDE 13

THE RELATIVE STIFFNESS : AN INDICATION OF CORNEOCYTE MATURITY

Exploration of the maturation process

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Relative stiffness N2 N7 N14

Cornified envelope Keratin fibers

immature mature superficial profound Intracellular stiffness

  • 1. Moisture gradient
  • 2. Water holding capacity

❖ Ongoing enzymatic processing of filaggrin ❖ Folding and cross-linking of keratin filaments

Milani et al, J. Mol. Rec. 2017

slide-14
SLIDE 14

THE RELATIVE STIFFNESS : AN INDICATION OF CORNEOCYTE MATURITY

Exploration of the maturation process

CE stiffness

  • 1. Cross-linking during maturation

JA Segre et al, Nat Genet, 1999

slide-15
SLIDE 15

Exploration of the maturation process

  • 1. Physical-Mechanical barrier
  • 2. Mechanical constraint likely

contributes to proneness to desquamation

Rigid – « stronger » Soft – « fragile »

Mechanical resistance Mechanical constraint OPTIMAL DESQUAMATION

slide-16
SLIDE 16

Understanding age-induced mechanical alterations of the barrier

Structural and molecular modification Rate of turnover is decreased Non-optimal desquamation … Biomechanical properties ? Aging

slide-17
SLIDE 17

CORNEOCYTE STIFFNESS INCREASES WITH AGE

Understanding age-induced mechanical alterations of the barrier

♀

100 200 300 400 500 600 700 800 20-30yrs 30-40yrs 40-50yrs 50-60yrs 60-70yrs

Ea (Mpa)

N = 2 N = 2 N = 2 N = 3 N = 6

Biniek et al. J of derm. 2015

Overall mesure of the SC Subcellular scale measurement

slide-18
SLIDE 18

CORNEOCYTE STIFFNESS INCREASES WITH AGE

Understanding age-induced mechanical alterations of the barrier

❑ Cross-linking of keratin filaments ❖ Oxydation ❖ Glycation ❑ Decreasing water holding capacity ❖ Less NMFs ❖ Increased intermolecular forces

♀

100 200 300 400 500 600 700 800 20-30yrs 30-40yrs 40-50yrs 50-60yrs 60-70yrs

Ea (Mpa)

N = 2 N = 2 N = 2 N = 3 N = 6

slide-19
SLIDE 19

INTERNAL STIFFNESS GRADIENT IS DISRUPTED

Understanding age-induced mechanical alterations of the barrier

0.2 0.4 0.6 0.8 1 1.2 20-30yrs 30-40yrs 40-50yrs 50-60yrs 60-70yrs

Relative stiffness

L2/L7 ❑ Less turnover ❑ Non-optimal desquamation ❖ Accumulation of mature corneocytes

slide-20
SLIDE 20

SC undergoes significant alterations

  • 1. Stiffer with higher frature stress
  • 2. Non-optimal desquamation

Rigid

Soft

Mechanical constraint OPTIMAL DESQUAMATION

Understanding age-induced mechanical alterations of the barrier

Rigid

Higher fracture stress

slide-21
SLIDE 21

Characterization of barrier dysfunction: atopic dermatitis

❑ Disrupted epidermal terminal differentiation ❑ Deficiency of structurale proteins ❑ Reduced lipids ❑ Abnormal skin barrier ❑ Inflammation ❖ GENETIC (FLG) ❖ ENVIRONNEMENT ❖ IMMUNOLOGIC FACTORS…

slide-22
SLIDE 22

Characterization of barrier dysfunction: atopic dermatitis

Haftek et al, in preparation

slide-23
SLIDE 23

Characterization of barrier dysfunction: atopic dermatitis

Ea (MPa) FLG+/+ FLG-/+ FLG+/+ FLG-/+ FLG-/- HEALTHY AD

N = 30 N = 50 N = 50 N = 80 N = 49

100 200 300 400 500 600 700 800

***

AD CORNEOCYTES ARE SOFTER

Haftek et al, in preparation

slide-24
SLIDE 24

Rigid – « stronger » Soft – « fragile » Mechanical resistance Mechanical constraint OPTIMAL DESQUAMATION Soft – « fragile » Mechanical resistance Mechanical constraint Soft – « fragile » OPTIMAL DESQUAMATION

Characterization of barrier dysfunction: atopic dermatitis

NORMAL SKIN AD SKIN

slide-25
SLIDE 25
  • The relative stiffness of corneocytes appears to be linked to their

maturity level

  • The rigidity of superficial corneocytes may likely contribute to

their proneness to optimal desquamation

  • Age induced accumulation of stiff corneocytes at the surface
  • Corneocytes from AD patients presented a lower stiffness than

healthy subjects

  • This approach can be used for minimally invasive evaluation of

various skin conditions and exploring the mode of action of pharmacological or cosmetic ingredients.

Conclusions

slide-26
SLIDE 26

Thanks you for attention

AD samples were collected in Dublin , Ireland, in Prof. Alan Irvine’s Dept .

slide-27
SLIDE 27

Bio BioMeca SAS 46, Allée d’Italie 69007 Lyon +33 (0)4 72 72 89 35 contact@bio-meca.com www.bio-meca.com

slide-28
SLIDE 28

Characterization of barrier dysfunction: atopic dermatitis

slide-29
SLIDE 29

CONFIDENTIAL

Supplemental data

Extracted from Roduit et al.,2009 Extracted from Milani et al.,2011

SIMULATION BY FINITE ELEMENTS

slide-30
SLIDE 30

CONFIDENTIAL

nm µm cm m Traction,Tension and Suction assay Indenter Micro indenter AFM cutometer