Transplanted Plantar Skin Cells Could Reduce Stump Injury

Re-engineering stump skin using skin cells from the sole of the feet could help amputees tolerate prosthetics more comfortably, according to a new study.

Researchers at Imperial College London (Imperial; United Kingdom) developed computational models to analyze the make-up of the skin on the soles of the feet, and how it behaves differently to regular skin under pressure. They found that the outermost layer of sole skin, the stratum corneum, plays the biggest role in protecting skin from tears and blisters, as it is much thicker in sole skin than other skin types. They also found that the thickness of the skin was not the key factor, but rather how the structural proteins, keratin and collagen, were arranged.

Plantar epidermis, which lies below the stratum corneum, contains far more total keratin, as well as different types of keratin, than in other skin, helping sole skin to resist breakages. Similarly, collagen is arranged in much thicker bundles, and the collagen fibers themselves are thicker. The combination of all these factors result in plantar skin that is tougher and more resistant to injury than body skin, which could be useful characteristics for amputees, if they could be incorporated in stumps. The researchers have already defined several potential avenues to do so.

These include incorporating genetic material into stump skin to help it grow thicker, and using sole skin-inspired skin grafts. The researchers also suggest manipulation of the genetic material that’s already in stump skin to change its make-up. For example, fibroblasts could be transplanted, which could trigger the production of collagen and alter the type of keratin produced, making skin layers thicker over time.

Alternatively, plantar skin cells could be grown in-vitro, which could then be grafted onto stumps. The study was published on October 9, 2019, in Science Advances.

“A thick stratum corneum is most important to protect skin from stress-induced injuries such as skin tears and blisters, while the composition of each skin layer is most important for protection against deformation-induced injuries such as pressure ulcers,” said senior author Claire Higgins, PhD, of the department of mechanical engineering. “The combined approach of multiscale mechanical testing and computational modeling can now be extended to investigate age-related skin changes and to enhance the load tolerance of engineered skin substitutes.”

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Imperial College London