The present research aimed to characterize soft tissue implants that were prepared with the use of crosslinked hyaluronic acid (HA) using two different crosslinkers and multiple reagent concentrations, alone or in combination with fibrin. The effect of the implants was evaluated in an in vivo mouse model, after 4 weeks in one group and after 12 weeks in the other. The explants were compared using analytical methods, evaluating microscopic images, and a histology analysis. The kinetics of the degradation and remodeling of explants were found to be greatly dependent on the concentration and type of crosslinker; generally, divinyl sulfone (DVS) resists degradation more effectively compared to butanediol diglycidyl ether (BDDE). The presence of fibrin enhances the formation of blood vessels, and the infiltration of cells and extracellular matrix. In summary, if the aim is to create a soft tissue implant with easier degradation of the HA content, then the use of 2–5% BDDE is found to be optimal. For a longer degradation time, 5% DVS is the more suitable crosslinker. The use of fibrin was found to support the biological process of remodeling, while keeping the advances of HA in void filling, enabling the parallel degradation and remodeling processes.

Fibrin membranes are widely used in regenerative medicine because they are biocompatible, biodegradable, contain growth factors, and support cell attachment. Most commonly they are produced from serum, but they can also be isolated from activated plasma. To increase the fibrinogen concentration of plasma, cryoprecipitate isolation is a possible solution. In this work, cryoprecipitate was prepared from fresh frozen plasma, isolated by plasmapheresis. The concentration of cellular elements, fibrinogen, total protein, and immunoglobulins among others was measured in different concentrations of cryoprecipitates. After activation with Ca-gluconate, fibrin membranes were produced in different thicknesses, and human mesenchymal stem cells were seeded onto the membranes. They were visualized by live-dead staining and their viability was determined by XTT. The platelet-derived growth factor AB content was quantified by ELISA. Our results showed that fibrinogen and platelet concentration can be multiplied in plasma by cryoprecipitate isolation, which affects the thickness and slightly the growth factor content of the membranes. According to live-dead staining, the thickness of the membranes does not influence cell attachment, and XTT measurement did not reveal a significant difference in cell attachment capacity either; however, a growing trend could be observed in the case of some membranes.

Scaffolds can provide a healthy environment for cell attachment, differentiation, proliferation, and migration in vitro and in vivo. Lysophosphatidic acid (LPA) is a naturally occurring bioactive phospholipid that is present in the serum mainly bound to albumin. The present study aims to investigate the biocompatibility of LPA. It also aims to determine the effect of different LPA species on the proliferation and migration of human bone marrow-derived mesenchymal stem cells (hBM-dMSCs) for LPA and human serum albumin (HSA) containing bone scaffold development. The HSA-LPA complex formation was assessed using Fourier-transform infrared (FTIR) spectroscopy. The effect of 18:1, 18:2, or 16:0 LPA alone, or in combination with 4% HSA, on cell viability and proliferation was determined by XTT. The cell migration was examined in a wound healing assay. The changes in the FTIR spectra of LPA-HSA compositions, compared with HSA alone, indicate the complex formation between the components. Our study showed that 18:1, 18:2, and 16:0 LPA species had no cytotoxic effects up to 10 µM concentration. The different LPA species increased the proliferation of hBM-dMSCs in a dose-dependent manner when administered in the presence of HSA, without an effect on the migration of this cell type. These findings make the in vivo application of LPA-HSA complex promising for bone regeneration.