Introducing aesthetic regenerative scaffolds: An immunological perspective.

Abstract

Skin aging arises from immunological responses to tissue deterioration and damage. Tissue repair processes encompass the regeneration of original tissue and 'scarless' wound healing seen in foetuses, and the extreme fibrotic responses and scarring seen in adults. Anti-aging aesthetic medicine uses interventions like biomaterial-based fillers to influence these immunological responses and renew aged tissue structure and function. At filler injection sites, an inflammatory response occurs that causes a spectrum of outcomes, ranging from tissue regeneration to fibrosis and filler encapsulation. Importantly, the resulting inflammatory pathway can be predetermined by the biomaterial injected. By understanding this immunological process, we can develop Aesthetic Regenerative Scaffolds (ARS) - aesthetic injectable biomaterials - to direct inflammatory wound healing away from chronic, fibrotic responses, and towards physiological tissue regeneration. We identified and reviewed literature on the immunological and cellular responses to injected dermal fillers, whereby the wound healing response to the injection was moderated under the influence of an injected biomaterial. We described the mechanisms of dermal wound healing and the use of ARS to direct healing towards tissue regeneration instead of scarring. We also summarised studies on extracellular matrix remodeling by calcium hydroxylapatite. We found that Calcium hydroxylapatite fillers produce collagen as they gradually degrade and their spherical structures serve as a scaffold for tissue regeneration. Furthermore, CaHA improved fibroblast contractility, collagen type III and elastin production, proliferation and angiogenesis with less inflammation than hyaluronic acid fillers. Regneration pathways can be influenced at specific points between a facial filler biomaterial and the wound healingmechanisms at its site of implantaion. Physicians can select scaffolds that direct the immune response away from a fibrotic chronic inflammatory pathway and towards regeneration to enable true repair of the aging skin.