Biostimulatory effects of low-level laser therapy on epithelial cells and gingival fibroblasts treated with zoledronic acid

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Low-level laser therapy (LLLT) has been considered as an adjuvant treatment for bisphosphonate-related osteonecrosis, presenting positive clinical outcomes. However, there are no data regarding the effect of LLLT on oral tissue cells exposed to bisphosphonates. This study aimed to evaluate the effects of LLLT on epithelial cells and gingival fibroblasts exposed to a nitrogen-containing bisphosphonate-zoledronic acid (ZA). Cells were seeded in wells of 24-well plates, incubated for 48 h and then exposed to ZA at 5 mu M for an additional 48 h. LLLT was performed with a diode laser prototype-LaserTABLE (InGaAsP-780 nm +/- 3 nm, 25 mW), at selected energy doses of 0.5, 1.5, 3, 5, and 7 J cm(-2) in three irradiation sessions, every 24 h. Cell metabolism, total protein production, gene expression of vascular endothelial growth factor (VEGF) and collagen type I (Col-I), and cell morphology were evaluated 24 h after the last irradiation. Data were statistically analyzed by Kruskal-Wallis and Mann-Whitney tests at 5% significance. Selected LLLT parameters increased the functions of epithelial cells and gingival fibroblasts treated with ZA. Gene expression of VEGF and Col-I was also increased. Specific parameters of LLLT biostimulated fibroblasts and epithelial cells treated with ZA. Analysis of these in vitro data may explain the positive in vivo effects of LLLT applied to osteonecrosis lesions.235Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2009/54722-1, BP.DR 2009/52326-1]CNPq [301029/2010-1

HydroGEV: Extracellular Vesicle-Laden Hydrogel for Wound Healing Applications

Chronic wounds contribute a substantial social and economic burden on the healthcare system. The global cost of wound treatment was about $19.8 Billion USD in 2019. Healing of chronic wounds takes typically more than 3 months. Current treatments are ineffective and do not always promote wound closure, which requires the activation of multiple cell types. Extracellular vesicles (EVs) contain multiple biomolecules that influence surrounding cells and thus have large capacity to promote tissue repair. To harness the chemoattractant properties of EVs, we developed an extracellular vesicle-laden hydrogel (HydroGEV) with optimized stiffness to promote functional tissue repair, since both mechanical and biological factors influence cell growth and subsequent tissue repair. EVs were isolated and purified from placental stem cells, characterized and incorporated into a gelatin-based hydrogel (GHPA) with different relative stiff-nesses (low, medium and high) determined by crosslinking density. The EVs were found to increase the migration capability of cells in a migration assay, confirming their strong chemoattractant properties and supporting their application for cell recruitment in wound healing. When incorporated into GHPA hydrogels, the EVs effectively improved cell attachment regardless of the stiffness of the hydrogels. Importantly, we demonstrated that by optimizing hydrogel stiffness it was possible to achieve higher cell proliferation and more phenotypic morphology. These promising results support the potential of HydroGEV as a better therapeutic option for patients with acute or chronic wounds