Marine sponge collagen-derived bioactive products and biomaterials for the development of cellular supports for tissue engineering and oxidative stress protection of human skin cells

Collagen is involved in the formation of complex fibrillar networks able to provide the tridimensional support and to ensure the structural integrity of many tissues. Its low immunogenicity and mechanical properties allow the use of this molecule as a biomaterial suitable as support for in vitro monolayer cell cultures mimicking in vivo basal membranes, for the development of cell culture 3D matrices as well as for tissue engineering and regenerative medicine (TERM) strategies in human health issues. Here, we used four different methods to obtain sponge collagenous fibrillar suspensions (FSs) from C. reniformis demosponge which were then chemico-physically and biologically characterized, in terms of collagen and glycosaminoglycans content, viscous properties, biocompatibility and antioxidant activity (1). These four FSs were then tested for their capability to generate thin sponge collagenous membranes (SCMs) suitable for TERM and in vitro cell monolayer culture purposes. Two types of FSs were able to generate SCMs and showed good mechanical properties, enzymatic degradation resistance, water binding capacity and antioxidant activity. Interestingly, they showed good biocompatibility for both fibroblast and keratinocyte cells cultured onto the various SCMs opening the possibility for the use of these thin membranes for TERM purposes and for the setup of in vitro assays of human skin cells alternative to animal testing. Furthermore, besides their role as structural supports and scaffolds, marine collagen and marine collagen hydrolysates may also possess interesting bioactive properties, which to date, in some organisms like sponges, have been poorly investigated. Thus, starting from the abovementioned C. reniformis collagen FSs, we obtained four HPLC-purified fractions of trypsin-digested extracts (MCHs) of which we studied the in vitro toxicity, antioxidant, wound healing and photo-protective properties by use of cellular in vitro assays alternative to animal testing (2). The four MCHs had no degree of toxicity and were able to stimulate cell growth. They showed a significant antioxidant activity in H2O2- or quartz-stimulated macrophages, they stimulated wound healing in a 2D in vitro cell assay and they promoted significant cell survival in an in vitro assay reproducing damages from UV-radiation on skin cells. Overall, our data, obtained by the sole use of alternative methods to animal testing, open the way to the use of C. reniformis MCHs in drug and cosmetic formulations for damaged or photo-aged skin repair