Increment of subcutaneous adipose tissue is associated with decrease of elastic fibers in the dermal layer.
Ezure T, Amano S.
Exp Dermatol. 2015 Jul 21. doi: 10.1111/exd.12816. [Epub ahead of print]
Obesity is the big health problem of industrialized countries.It is measured by the Body Mass Index (BMI) which is a score obtained by dividing the weight (in Kg) by the squared height (in meters) (Kg/m2):
-A score over 25 indicated excess weight
-A score over 30 defines obesity
Fat accumulation takes place mainly in the subcutaneous layer (under the dermis) and the volume increase of fat is mainly due to the increase in size of adipocytes (fat cells)
Obesity leads to many skin problems, two of which are pressure ulcers and delayed wound healing. To read more about skin problems related to obesity, click HERE.
This Japanese study was done on abdominal skin obtained from cosmetic procedures done in 27 middle-aged females (49.5 (40-59)) with various BMI’s (31 (20-42))
Results show that with increased there is an increase in size of adipocytes and a proportional decrease in the quantity of elastic elastic fibers in the dermis
–Gene analysis shows and increased expression and secretion (by fibroblasts) of Matrix Metalloproteinase 9 (MMP9)
-Nuclear translocation (activation) of AP-1, a downstream Extracellular-signal Regulated Kinase (ERK) signalling molecule, is also observed in enlarged adipocytes
-This is stopped by blocking ERK.
What are elastic fibers ?
-Elastic fibers (Elastin) are the molecules which give to the skin its flexibility (and return deformed skin to its resting state)
-They are located in the dermis and amount to 10% of the fibers (collagen amounts to the other 90%). They are thin in the papillary dermis and thicker in the reticular dermis.
-They are produced by fibroblasts (which also produce the enzymes that degrade them)
They can be compared to rubber bands:
-When new, they stretch without breaking and go back to their initial mechanical position afterwards
-However, aged rubber bands are fissured at “rest” and break very easily when stretched and thus are unable to return skin to its initial position.
-Elastic fibers play an important in functional adaptive skin and they are degraded in obese individuals through ERK-dependant signals sent by adipocytes
-Diabetes can also present with pressure ulcers and delayed wound healing but they are the result of microvasculature problems (To read more on skin problems related to diabetes, click HERE)
-Diabetes and Obesity are often associated, particularly in type 2 diabetes. It would be interesting to see if the is an additive effect of elastic fiber degradation when diabetes is associated with obesity. Also it would be interesting to see if elastic fiber degradation is present in diabetes type I, where obesity is often absent.