The skin regeneration potential of a pro-angiogenic secretome from human skin-derived multipotent stromal cells.

Multipotent stromal cells stimulate skin regeneration after acute or chronic injuries. However, many stem cell therapy protocols are limited by the elevated number of cells required and poor cell survival after transplantation. Considering that the beneficial effects of multipotent stromal cells on wound healing are typically mediated by paracrine mechanisms, we examined whether the conditioned medium from skin-derived multipotent stromal cells would be beneficial for restoring the skin structure of mice after wounding. A proteomic characterization of skin-derived multipotent stromal cell-conditioned medium was performed, and the angiogenic function of this secretome was investigated in vitro using an endothelial cell tube formation assay. We then applied the skin-derived multipotent stromal cell-conditioned medium directly to full-thickness excisional wounds or embedded it into carrageenan or poly(vinyl alcohol) hydrogels to monitor tissue regeneration in mice. Biological processes related to wound healing and angiogenesis were highlighted by the analysis of the skin-derived multipotent stromal cell secretome, and a pro-angiogenic capacity for promoting tubule-like structures was first confirmed in vitro. Skin wounds treated with skin-derived multipotent stromal cell-conditioned medium also displayed increased angiogenesis, independently of the association of the conditioned medium with hydrogels. However, improvements in wound closure and epidermis or decreased inflammatory cell presence were not observed. Hence, the use of the secretome obtained from human skin-derived multipotent stromal cells may be a potential strategy to aid the natural skin repair of full-thickness lesions mainly based on its pro-angiogenic properties.

Carrageenan hydrogel as a scaffold for skin-derived multipotent stromal cells delivery.

Carrageenan is a thermoreversible polymer of natural origin widely used in food and pharmaceutical industry that presents a glycosaminoglycan-like structure. Herein, we show that kappa-type carrageenan extracted by a semi-refined process from the red seaweed Kappaphycus alvarezii displayed both chemical and structural properties similar to a commercial carrageenan. Moreover, both extracted carrageenan hydrogel and commercial carrageenan hydrogel can serve as a scaffold for in vitro culture of human skin-derived multipotent stromal cells, demonstrating considerable potential as cell-carrier materials for cell delivery in tissue engineering. Skin-derived multipotent stromal cells cultured inside the carrageenan hydrogels showed a round shape morphology and maintained their growth and viability for at least one week in culture. Next, the effect of the extracted carrageenan hydrogel loaded with human skin-derived multipotent stromal cells was evaluated in a mouse model of full-thickness skin wound. Macroscopic and histological analyses revealed some pointed ameliorated features, such as reduced inflammatory process, faster initial recovery of wounded area, and improved extracellular matrix deposition. These results indicate that extracted carrageenan hydrogel can serve as a scaffold for in vitro growth and maintenance of human SD-MSCs, being also able to act as a delivery system of cells to wounded skin. Thus, evaluation of the properties discussed in this study contribute to a further understanding and specificities of the potential use of carrageenan hydrogel as a delivery system for several applications, further to skin wound healing.

Seaweeds: an opportunity for wealth and sustainable livelihood for coastal communities.

The European, Canadian, and Latin American seaweed industries rely on the sustainable harvesting of natural resources. As several countries wish to increase their activity, the harvest should be managed according to integrated and participatory governance regimes to ensure production within a long-term perspective. Development of regulations and directives enabling the sustainable exploitation of natural resources must therefore be brought to the national and international political agenda in order to ensure environmental, social, and economic values in the coastal areas around the world. In Europe, Portugal requires an appraisal of seaweed management plans while Norway and Canada have developed and implemented coastal management plans including well-established and sustainable exploitation of their natural seaweed resources. Whereas, in Latin America, different scenarios of seaweed exploitation can be observed; each country is however in need of long-term and ecosystem-based management plans to ensure that exploitation is sustainable. These plans are required particularly in Peru and Brazil, while Chile has succeeded in establishing a sustainable seaweed-harvesting plan for most of the economically important seaweeds. Furthermore, in both Europe and Latin America, seaweed aquaculture is at its infancy and development will have to overcome numerous challenges at different levels (i.e., technology, biology, policy). Thus, there is a need for regulations and establishment of "best practices" for seaweed harvesting, management, and cultivation. Trained human resources will also be required to provide information and education to the communities involved, to enable seaweed utilization to become a profitable business and provide better income opportunities to coastal communities.

Cultivation of the red algae Kappaphycus alvarezii in Brazil and its pharmacological potential

Kappaphycus alvarezii (Rhodophyta, Gigartinales) is a red algae widely cultivated as the main source of raw material for the carrageenan industry. This hydrocolloid is normally used in the food industry as a gelling and stabilizing agent. The facility of its commercial farming based on vegetative propagation promoted the success of the aquaculture of this macroalgae that consequently stimulated studies focusing on new potential uses of this resource. This work presents a brief review of the studies related to K. alvarezii cultivation in southern and southeastern Brazil, the latest discoveries in the world concerning pharmacological studies with this species and the advantages of the use of carrageenan as a source of dietary fiber, cholesterol reducer, and antioxidant, anti-viral and anti-cancer compounds, as well as the effects in hemagglutination activity.