13. Skin Reconstruction and Dermal Equivalents Flashcards
How often does the body replace skin?
1 month entirely new layer of skin
What are the layers of skin?
Epidermis - Keratinocytes (90%) melanocytes
Dermis - Fibroblasts (matrix), endothelial cells, hair follicle cells
What are the 4 grades of burns?
Epidermal burn Partial thickness burn Deep dermal burn - Mesh graft to treat Full thickness burn
What is the ultimate goal of burn repair?
Reduce scar formation
What are some complications associated with burns?
Delayed healing increases scar risk
Infection leads to delay in healing
Oedema increases infection risk
Inflammation increases oedema
What are the aims of cell based therapies?
Reduce inflammation
Decrease time to cover wound
What are some cell types being used in cell based therapies of burns?
Keratinocytes - epithelial cover
Fibroblasts - dermal matrix
Melanocytes - pigmentation
Endothelial cells - revascularisation
What are combined therapies and what do they treat?
Dermal matrices and scaffolds
- Greater depth
What is the process for a skin graft?
Skin taken
Meshed to cover larger surface area
Mesh pattern of healed skin
What are some complications on skin grafts?
Donor site morbidity, ugly
What are the three types of grafts?
Xenografts
Allografts
Autografts
What are the drawbacks of xenografts?
rejected very often
Temporary dressing
What are the drawbacks of allografts?
Eventual rejection
Immunosupressive therapy must be given
Cross contamination
Are autografts and allografts cultured?
They can be. Depends on how you feel
What are cultured epithelial autograft sheets?
Cultured using large full thickness biopsy
3 - 10 cell layers thick
Clipped to petrolatum gauze
Available up to 3-5 weeks after initial biopsy
What is the optimal surgical timing in regards to scar formation?
10 days = 4%
21 days = 78% risk
Why is the need for cell culture a limitation for burn treatment?
Increase risk of scar formation due to time required to culture cells
What did Fiona Wood do so well?
Developed Autologous non-cultured Skin Cell Based Therapy
What shift is happening in the treatment of burns?
Moving from skin derived cells to multipotent/pluripotent cells
What are the origin of stem cells used in treatment of burns?
Hematopoietic
Mesenchymal
Adipose derived
reprogrammed
What are some of the functions of these stem cells?
Immune modulation (anti-inflammatory)
Growth factor stores
Cell engraftment
What is the importance of ECM?
Previously though ECM was passive scaffold However..... Physical characteristics important - Strength - Stress Biological characteristics also important - Secreted factors - Glycosylation/sugars
What are matrices good for in treatment of burns?
Enhance recovery in deep burns
Rapid replacement of dermal template
Limited by angiogenesis however
What is an example of a matrice used clinically?
INTEGRA
3 weeks until epidermal cells plated
Collagen based
What is still currently the most common treatment for burns?
Split thickness skin grafts (STKG)
