Ageing Skin Dr Bill Revell

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Ageing SkinDr Bill Revell

• AGEING
• Process of progressive generalised impairment of
  function
• Resulting in an increasing age- specific death
  rate
• Tom Kirkwood

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Ageing

• Results from accumulation of un-repaired damage
  of somatic cells and tissues
• Progressive failure of maintenance mechanisms to
  respond to environmental attrition
• Free radical damage may offer a unifying theory
  for cellular senescence, underlying human ageing
  and age related diseases

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Deteriorating Tissue Function

• Associated with change in cell functioning
• /- Change in cell turnover when old or defective
  cells are not replaced

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age related changes in metabolic functions

• Reduced oxidative phosphorylation by mitochondria
  
• Diminished synthesis of structural, enzymatic and
  regulatory proteins
• Decreased capacity for uptake of nutrients
• Increased DNA damage and diminished repair of
  chromosomal damage
• Accumulation of oxidative damage in proteins and
  lipids (eg lipofuscin pigment)
• Accumulation of advanced glycosylation end
  products

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Morphological alterations

• Irregular and abnormally lobed nuclei
• Swollen, pleomorphic and vacuolated mitochondria
• Decreased endoplasmic reticulum
• Distorted Golgi apparatus

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Ageing skin a preamble.

• Huge efforts to hide and disguise
• Gerontological discussion has little to do with
  morbidity or mortality very few patients die of
  old skin, or succumb to skin failure
• Importance is primarily psychological
• Emotional impact of skin ageing should not be
  underestimated

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Ageing skin

• Wrinkled
• Most pronounced on sun exposed parts
• Age or liver spots
• Loss of hair
• Sagging facial muscles
• Increased fragility
• Skin contains less collagen and elastin abnormal

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changes to collagen and elastin

• Thinner less elastin less collagen
• Abnormal elastin and collagen
• Wrinkling most pronounced on sun-exposed skin

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Collagen Cross Links

• Eg intermolecular cross links between lysine
  residues in adjacent collagen helices
• Non-reducible cross links increase with age
• Arise as a side effect of free radical damage

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Advanced Glycosylation End Products

• Post-translational modification of collagen by
  sugar (AGE products)
• Non-enzymatic attachment of glucose to proteins
• Formation of irreversible cross links

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Structural age changes in skin
dermis
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Age related changes normal ageingEpidermis

• Epidermis thinner
• Increased scaling off
• Declining rate of cell division
• Decrease in dermal papillae
• Decrease in interdigitation
• epidermis held less tightly
• Looser feel of ageing skin
• By age 80yr keratinocyte turnover in epidermis
  slows to 50

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Age related changes normal ageingDermis

• Reduction in fibroblast numbers
• Less matrix turnover
• Dermis thins more than epidermis (transparency)
• Collagenous fibres become larger and coarser
• Fat, water, matrix content diminishes
• Elastic fibres less resilient
• Formation of cross links some calcification
• Skin less able to smooth out
• Wrinkles
• Loss of smooth padding provided by fat cells of
  the hypodermis

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Age related changes normal ageingDermis

• Reduction in sweat glands and sebaceous glands
• Gradual atrophy
• Sweat less drier and scaly skin
• Reduced ability to regulate body temperature
• Heat exhaustion more likely
• Generalised reduction of blood flow to skin
• Skin surface cooler slow growth of hair and
  nails
• Nails yellowish, ridged, thicker with Ca2
  deposits
• Decrease in hair follicles, loss of body hair
• cf (males) eyebrow, nostril, ear hair becomes
  coarse and grow more rapidly
• Reduced hair pigment grey/white is default
  colour

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Age related changes normal ageingHypodermis

• Layer of loose connective tissue, containing fat
• Subcutaneous tissue not part of skin
  (technically)
• . but changes affect skin.
• Generalised loss of fat most obvious in face and
  limbs
• Major cause of wrinkles
• old age is when, upon getting out of the bath,
  you notice the full length mirror is steamed up
  and you are glad of it (Modern Maturity)

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Age related changes normal ageingHypodermis

• Loss of subcutaneous fat also loss of padding
• Combine with reduction of blood supply to skin
• Bed sores in areas of constant pressure over bony
  prominences
• Loss of fat
• Diminished insulation allows heat to escape
• Need to keep rooms warmer than young people can
  tolerate

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Age or liver spots

• Intrinsic resulting from the ageing process
• Resulting from UV damage photo-ageing
• dermatoheliosis
• Free radical damage
• Lipofuscin deposition in cells, often in
  secretary cells of sweat glands
• End product of lipid peroxidation

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SenileFRECKLESinvolving melanocytes

• pigmented area (melanin) surrounded by
  normal-appearing skin.
• melanocytes are present may be increased in
  number
• may evolve slowly over years, or may be eruptive
  and appear suddenly
• Pigmentation may be homogeneous or variegated,
  with a colour ranging from brown to black.

cf solar LENTIGO
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Age related dysfunctions

• Senile angiomas
• 75 gt70yr
• Elevated clusters of dilated capillaries
• Seborrheic keratosis
• Benign epidermal tumours
• Greasy wart-like crust often forms on surface of
  tumours
• Senile pruritis (itching)
• Loss of oil secreting sebaceous gland
• Dry, less pliant skin cracks
• Deep fissures that exude tissue fluid

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Herpes Zoster(shingles)
Viral disease Peak incidence 50-70yrs Varicella
(chicken pox) when young Remains dormant in
nervous system When reactivated, attacks sensory
nerve fibres and skin supplied by nerves Itching,
red papules, fluid filled vesicles, dries down
and forms crust, scales off, leaving pigmented
area 1 2 weeks, pain for months
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Skin Cancerscancers of all types increase with
age

• Melanoma most serious
• Associated with sun UV light
• Develops in pigment cells (melanocytes) of a
  pre-existing epidermal mole

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Non-melanoma skin cancers gt50 pink, red or white

• Basal cell carcinoma
• Most common
• Develops from cells in basal layer of epidermis
• Most common in regions with strong sunlight
• Most prevalent in light skinned races
• Head and neck usually
• Rarely metastasise
• Variously reddish patches small open sores
  bumps
• Growths can invade underlying tissue

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Non-melanoma skin cancers

• Squamous cell carcinoma
• Less common
• Associated with excessive sun exposure
• More common in elderly, esp. older men
• Appears as a wart
• Often in form of hard nodule, with small reddened
  areas showing through surface
• May be ulcerous