Nanoemulsions and topical creams for the safe and effective delivery of lipophilic antioxidant coenzyme Q10.

Emulsion-based delivery systems have been developed to increase the topical bioavailability of lipophilic active compounds within skin membrane. The aim was to develop nanoemulsion from natural sources (rapeseed oil) with the same sources of pure phospholipids (lecithin) rich on mono and polyunsaturated fatty acids for encapsulation of hydrophobic antioxidant (Coenzyme Q10) giving nanoemulsion with double functionality. Nanoemulsions were used for cream preparation using xanthan gum and carboxylmethylcellulose as texturizing agents. The physico-chemical properties, toxicity and biocompatibility were evaluated. Physical stability was followed under different storage temperatures (25; 37 and 50 °C) for one month and revealed stable systems with 150 nm particle size. Anionic thickening addition influenced the electrophoretic mobility but not the size distribution. The addition of polyanionic thickening in nanoemulsions promoted negative surface charge that increased electrostatic repulsive forces between droplets avoiding destabilization phenomena such as coalescence and Ostwald ripening. Moreover, chemical stability evaluation of components confirmed the absence of interactions. FTIR analysis indicated the vibration band position of cis double stretching of unsaturated fatty acids between 3009 and 3006 cm-1, which characterized the non-oxidized oils with same intensities before and after sonication. Antioxidants measurement shown that CMC significantly reduced antioxidant activity due to masking action of CoQ10 functional groups by the carboxylmethylcellulose gum conversely to xanthan gum addition. Finally, in vitro biocompatibility results shown that CoQ10 protected the DNA, and xanthan gum improve glucose metabolism inducing a better cell growth, while carboxymethylcellulose which was not metabolized by fibroblast cell inducing lower growth rate.

Evaluation of the pro-angiogenic effect of nanoscale extracellular vesicles derived from human umbilical cord mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are a common tool in regenerative medicine. The nanoscale extracellular vesicles (nEVs) secreted by these cells were recently brought up to light thanks to their therapeutic potential. In this study, we assessed the in vitro behaviour of human umbilical vein endothelial cells (HUVECs) exposed to nEVs derived from human umbilical cord mesenchymal stem cells (hUC-MSCs). Nanoscale extracellular vesicles were isolated and characterized by NanoSight® and flow cytometry. HUVECs were stimulated with various concentrations of nEVs. To assess nEV interactions with HUVECs, confocal microscopy and angiogenesis assay were performed. The use of nEVs derived from hUC-MSCs was able to produce positive outcomes on HUVECs by acting on their angiogenic potential.

Transforming growth factor-beta 1 or ascorbic acid are able to differentiate Wharton's jelly mesenchymal stem cells towards a smooth muscle phenotype.

Wharton's jelly mesenchymal stem cells (WJ-MSCs) are widely used in tissue engineering. In vascular engineering, the ability to obtain a vessel replacement with contractile smooth muscle cells (SMC) is a key factor. In this work, we demonstrated that WJ-MSCs differentiate towards a SMC phenotype with various stimulations in vitro and that the modification of redox state could be involved. WJ-MSCs were isolated from umbilical cords. After their expansion, the cells were stimulated with ascorbic acid (AA, 300 µM) or transforming growth factor (TGF)-ß1 (1 to 5 ng/mL). SMC markers were analyzed by Western blot. Modification of redox state was evaluated by reactive oxygen species (ROS) production and glutathione (GSH) content measurements. TGF-ß1 or AA-stimulated WJ-MSCs express early and intermediate SMC markers. TGF-ß1 (5 ng/mL) modifies the redox state by a ROS production and a GSH content drop, while AA has no effect. This work showed that TGF-ß1 and AA are effective SMC phenotype inducers to differentiate WJ-MSCs.

Efficiency of emulsifier-free emulsions and emulsions containing rapeseed lecithin as delivery systems for vectorization and release of coenzyme Q10: physico-chemical properties and in vitro evaluation.

To improve the encapsulation and release of coenzyme Q10 (CoQ10), emulsifier-free-emulsions were developed with a new emulsification process using high-frequency ultrasound (HFU) at 1.7MHz. Nano-emulsions containing CoQ10 were prepared with or without rapeseed lecithin as an emulsifier. The emulsions prepared with HFU were compared with an emulsion of CoQ10 containing emulsifier prepared with the same emulsification technique as well as with emulsions prepared with low-frequency ultrasound coupled with high-pressure homogenization (LFU+HPH). The physico-chemical properties of the emulsions were determined by average droplet size measurement with nano-droplet tracking analysis, droplet surface charge with ζ potential measurement, surface tension and rheological behaviour. Emulsions made by LFU+HPH with an emulsifier showed lower droplet sizes due to cavitation generated by the HFU process. Surface tension results showed that there was no significant difference between emulsions containing lecithin emulsifier regardless of the preparation process or the inclusion of CoQ10. In vitro biocompatibility tests were performed on human mesenchymal stem cells in order to show the cytotoxicity of various formulations and the efficiency of CoQ10-loaded emulsions. In vitro tests proved that the vectors were not toxic. Furthermore, CoQ10 facilitated a high rate of cell proliferation and metabolic activity especially when in an emulsifier-free formulation.

Brillouin spectroscopy: a new tool to decipher viscoelastic properties of biological scaffold functionalized with nanoscale films.

BACKGROUND: In tissue engineering, the endothelialization of vascular scaffold can be a crucial step to improve graft patency. A functional cellularization requires coating surfaces. Since 2003, our group used polyelectrolyte multilayer films (PEMFs) made of poly(allylamine hydrochloride) and polystyren sulfonate to coat luminal surface of blood vessel. Previous results showed that PEMFs have remarkable effect on cellular behavior: adhesion, proliferation, differentiation. However, no method seems adapted for in vitro measurement of the viscoelastic shift after PEMFs buildup. OBJECTIVE: In this present work, we proposed to use a new analytical method based on Brillouin spectroscopy (BS) to investigate the influence PEMFs coating on vessel intrinsic viscoelasticy. METHODS: On human umbilical arteries and rabbit vessels, PEMFs were buildup and the luminal surfaces viscoelasticy were measuring by BS. RESULTS: It seems that these films do not alter dynamic functionality and BS could be an interesting method for understanding the role of the tissue architecture, the interrelation between the different structures constituting the wall and the influence of this architecture on the tissue behavior, especially with the characterized components of the different vascular wall. CONCLUSION: The ability of BS to characterize biological samples opens potential applications in tissue engineering field, especially as a tool for a better understanding of vascular diseases.

Reversing charges or how to improve Wharton's jelly mesenchymal stem cells culture on polyelectrolyte multilayer films.

BACKGROUND: Polyelectrolyte multilayer (PEMs) films made of poly(allylamine hydrochloride) (PAH) as polycation and poly(styrene sulfonate) (PSS) as polyanion, with a PAH ending layer, can be used as a coating in order to improve the anti-thrombogenicity and patency of vascular grafts in vascular engineering field. They induce strong adhesion of mature endothelial cells on glass, expanded polytetrafluoroethylene and cryopreserved arteries. Despite their outstanding effect on mature and progenitor endothelial cells, PEMs ending with PAH showed a poor outcome on Wharton's jelly mesenchymal stem cells (WJ-MSCs) culture. OBJECTIVE: The aim of this work was to examine the influence of the ending charge of PEMs on WJ-MSCs behavior. METHODS: WJ-MSCs amplified until the 3rd passage were seeded and cultured on (PAH-PSS)3-PAH and on (PAH-PSS)4 coated glass for 10 days. Stem cell phenotype was checked by flow cytometry and cell morphology was followed by bright field microscopy. RESULTS: Flow cytometry analysis showed that WJ-MSCs were positive for MSC's markers CD73, CD90 and CD105 and negative for hematopoietic markers CD34 and CD45. Light microscopy showed development of nodule-like structures after 10 days of culture on (PAH-PSS)3-PAH, which resulted in a disturbance of cell monolayer. Whereas WJ-MSCs cultured on (PAH-PSS)4 ending with PSS showed a normal cell growth like on collagen and reached confluence after 10 days. CONCLUSION: The culture surface seems to have a determining role in WJ-MSC's "spatial" behavior, which could be considered in the field of tissue engineering.