Facial reconstruction by biosurgery: cell transplantation versus cell homing

Abstract

The face distinguishes one human being from another. When the face is disfigured because of trauma, tumor removal, congenital anomalies, or chronic diseases, the patient has a strong desire for functional and esthetic restoration. Current practice of facial reconstruction using autologous grafts, synthetic fillers, and prostheses is frequently below the surgeon's and patient's expectations. Facial reconstruction is yet to take advantage of recent advances in seemingly unrelated fields of stem cell biology, chemical engineering, biomaterials, and tissue engineering. "Biosurgery," a new concept that we propose, will incorporate novel principles and strategies of bioactive cues, biopolymers, and/or cells to restore facial defects. Small facial defects can likely be reconstructed by cell homing and without cell transplantation. A critical advantage of cell homing is that agilely recruited endogenous cells have the potential to harness the host's innate capacity for regeneration, thus accelerating the rate of regulatory and commercialization processes for product development. Large facial defects, however, may not be restorable without cell delivery per our understanding at this time. New breakthrough in biosurgery will likely originate from integrated strategies of cell biology, cytokine biology, chemical engineering, biomaterials, and tissue engineering. Regardless of cell homing or cell delivery approaches, biosurgery not only will minimize surgical trauma and repetitive procedures, but also produce long-lasting results. At the same time, caution must be exercised against the development of products that lack scientific basis or dogmatic combination of cells, biomaterials, and biomolecules. Together, scientifically derived biosurgery will undoubtedly develop into new technologies that offer increasingly natural reconstruction and/or augmentation of the face.

FIG. 1.

Divergence of two biological approaches for facial reconstruction or augmentation. Cells, including stem/progenitor cells, may be injected in soluble matrices or seeded in preformed anatomically correct matrices for the healing or augmentation of dental, oral, and craniofacial defects, as shown in the schematics on the right. However, cell delivery is associated with potential commercialization and regulatory hurdles such as excessive cost of cell harvest, processing, packaging/shipping/storage, contamination, and clinical acceptance rate. In comparison, biological cues can be encapsulated in biocompatible microparticles such as injectables or loaded into preformed, anatomically correct matrices for the healing or augmentation of dental, oral, and craniofacial defects, as shown in the schematics on the right. Biological cues are capable of homing the host's endogenous cells, including stem/progenitor cells, and can be prepackaged and made available in a medical or dental office at the time of clinical need, with several previous products approved for clinical applications. Cell homing and cell delivery combined is the foundation for facial biosurgery that minimizes surgical trauma and yield long-lasting esthetic and functional outcome, in comparison with shortcomings of current practice of tissue grafting and synthetic fillers. Color images available online at www.liebertonline.com/ten.

FIG. 2.

Escalating magnitude of regulatory and commercialization challenge of different products for healing dental, oral, and craniofacial defects. The magnitude of regulatory and commercialization difficulty increases from the left to the right. Biocompatible material scaffolds or biological cues alone typically cost the least to develop commercially and have examples of prior regulatory approval for clinical applications. This is followed closely by the incorporation of cues in scaffolds. Cell delivery with or without biological cues and/or scaffolds represents the most costly and challenging approach for regulatory approval and commercialization. Color images available online at www.liebertonline.com/ten.