Sub-Populations of Dermal Skin Fibroblasts Secrete Distinct Extracellular Matrix: Implications for Using Skin Substitutes in the Clinic

Summary

Background

While several commercial dermo-epidermal scaffolds can promote wound healing of the skin, the achievement of complete skin regeneration still represents a major challenge.

Objective

We postulated that three dimensional structures derived through the physiological cell secretion of extracellular matrix (ECM) may be a bioinspired scaffold for skin tissue engineering. In the present study we performed a biological characterization of self-assembled ECMs from three different sub-populations of fibroblasts found in human skin; papillary fibroblasts (Pfi), reticular fibroblasts (Rfi), and dermal papilla fibroblasts (DPfi).

Methods

Fibroblast sub-populations were cultured with ascorbic acid to promote cell assembled matrix production for 10 days. Subsequently, cells were removed and the remaining matrices were characterized. Additionally, in another experiment, keratinocytes were seeded on the top of cell depleted ECMs to generate epidermal only skin constructs.

Results

We found that the ECM self-assembled by Pfi exhibited randomly oriented fibers associated with highest interfibrillar space, reflecting ECM characteristics which are physiologically present within the papillary dermis. Mass spectrometry followed by validation with immunofluorescence analysis showed that THROMBOSPONDIN 1 (THBS1) is preferentially expressed within the DPfi derived matrix. Moreover we observed that epidermal constructs grown on DPfi or Pfi matrices exhibited normal basement membrane formation, while Rfi matrices were unable to support membrane formation.

Conclusion

We argue that inspiration can be taken from these different ECMs, to improve the design of therapeutic biomaterials in skin engineering applications.

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