Elastin is an integral component of connective tissue that provides resilience and elasticity. It is composed of elastic fibers made of elastin protein. There are three types of elastic fibers - oxytalan, elaunin, and elastic fibers, located at different depths of the dermis. Elastin provides the skin with extensibility, elasticity, and resilience. It is synthesized from tropoelastin precursor proteins which are secreted into microfibrils and crosslinked to form insoluble elastic fibers through enzymatic processes. Elastin is important for various tissues and clinical disorders are associated with deficiencies in elastic fibers.

1. ELASTIN
Preethi chekuri

2. ELASTIC FIBRES
• Integral component of dermal connective
tissue
• It provides resilience & elasticity to the skin
• These are relatively minor component in
normal sun- protected adult skin
• less than 2–4% of the total dry weight of the
dermis.
• Reticular dermis : fibres consists of
horizontally oriented fibres which
interconnect to provide a network structure.

3. FUNCTIONS
• Extensibility
• Elasticity
• Resilience

4. CONVENTIONAL MICROSCOPY
• Oxytalan fibres
• Elaunin fibres
• Elastic fibres

5. OXYTALAN FIBRES
• More superficial
• Thin & oriented perpendicular to dermo
epidermal junction
• Ultrastructurally : composed of bundles of
tubular microfibrils
• 11 nm in diameter

6. ELAUNIN FIBRES
• Thin fibres which form a plexus within
papillary dermis parallel to dermo –
epidermal junction
• Spherules of elaunin that punctate this
plexus are called elastic globes.
• These are connected to elastic fibres of
reticular dermis that are alligned parallel to
skin surface

7. LASER SCAN MICROSCOPY

8. ELASTIN
• Initially synthesized as precursor
polypeptide : tropoelastin
• Consists of approximately 700 aminoacids
with molecular mass of 700 kDa
• It is one of the component of reticular
dermis

9. ELECTRON MICROSCOPY
• An amorphous electroluscent core
• Microfibrils - electron dense fibrils of insoluble
glycoprotein complexes
• 11nm diameter

10. BIO CHEMICALLY
• Elastin consists of linear ,polypeptide
tropoelastin subunits whose m.wt
72,000daltons
• rich in valine, proline & alanine
• It does not contains hydroxylysine or
covalently linked sugar residues & 1% of it
is composed of hydroxyproline

11. Amino Acids in Elastin
• Composed of amino acids.
• Valine, Glycine, Alanine and Proline.

12. BIO SYNTHESIS
• Biosynthesis of fibres by fibrocytes :
• 1.microfibrils of elastic fibres secreted in form of
grouped linear arrays in long cylindrical infolding of
cell surface,where polymerization occurs.
• 2. newly synthesized ,soluble,tropoelastin polypeptides
are secreted by fibrocytes into the pre-formed cylinder
of microfibrils
• By means of complex process that involves enzyme
lysyl oxidase polypeptides are linked by formation of
cross links : desmosines or isodesmosines

14. Four lysine chains can be combined to
form a desmosine cross-link

15. CYTOKINE & HORMONAL REGULATION
• Inflammatory mediators modulate elastin
gene expression
• They play a role in diseaes charecterized by
accumulation of elastic fibres in tissues
• Vitamin D3 modulates gene expression
• Incubation of fibroblast with vit D3 results in
80-90% decrease in total distribution of
tropoelastin
• Insulin like growth factor enhances gene
expression

16. IMAGE OF ELASTIC FIBRES

17. TISSUE DISTRIBUTION
• Lungs
• Elastic ligaments
• Skin
• Bladder
• Elastic cartilage
• Blood vessels

18. • Elastic fibres absent in : scars
: keloid
: dermatofibromas
• Decreased or absent in anetoderma

19. CLINICAL SIGNIFICANCE
• Marfan syndrome
• Emphysema caused by alpha -1 anti trypsin
deficiency
• Atherosclerosis
• Menkes syndrome
• Pseudo xanthoma elasticum
• Williams syndrome

20. THANK YOU