Wound healing treatment using insulin within polymeric nanoparticles in the diabetes animal model.

The aim of this work was to prepare chitosan nanoparticles containing insulin and to evaluate its therapeutic activity during wound healing in diabetic rats. The hypothesis that guided this study was that the combination of insulin within chitosan nanoparticles could stimulate the signaling pathway for wound healing. The chitosan nanoparticles were prepared by the ionotropic gelation method presenting average size of 183.3 ± 8.32 nm, polydispersity index (PDI) 0.397 ± 0.07 and zeta potential of 33.7 ± 2.45 mV for empty chitosan nanoparticles (EC) and 245.9 ± 25.46 nm and PDI 0.463 ± 0.01, and zeta potential of 39.3 ± 4.88 mV for chitosan nanoparticles containing insulin (IC). The insulin association efficiency was 97.19% ± 2.18. These nanoparticles and free insulin (FI) were incorporated within a hydrogel (Sepigel®) for topical application in the wound of 72 diabetic rats distributed in four groups: Sepigel® (S, control), free insulin (FI), empty chitosan nanoparticles (EC), and chitosan nanoparticles containing insulin (IC). The animals in each group were reorganized into three subgroups (n = 6) to assess their clinical signs after days 3, 7, and 14 from the beginning of treatments. Intense fibroplasias were observed in the free or insulin-chitosan nanoparticles groups. In the latter, a large number of blood vessels were observed at day 7th. Our data indicated that both empty and insulin-containing chitosan nanoparticles were able to stimulate inflammatory cell proliferation, and angiogenesis, followed by wound maturation.

The mycma_1113 Gene from Mycobacterium abscessus subsp. massiliense is Related to Siderophore Synthesis.

Iron (Fe) homeostasis control is important for both pathogen and the host. During infection, the host reduces the access of microorganisms to iron, however, studies have shown that virulent pathogens are capable to sequester Fe from host proteins, and establish the infection. M. abscessus subsp. massiliense (Mycma), that is resistant to most drugs used against tuberculosis, was responsible for outbreaks around the world showing increased virulence when compared to other rapidly growing mycobacteria. The goal of this study was to determine whether Mycma produce siderophores and if the mycma_1113 gene expression, a putative homolog of M. tuberculosis mbtB gene located in the mbt gene cluster, is related to the synthesis of these molecules. For that, the effect of different iron concentrations on the growth of Mycma, the expression of mycma_1113 gene, and the production of siderophores was evaluated in vitro and in vivo. It is shown that Mycma produce siderophores under iron deprivation conditions and mycma_1113 gene expression was influenced by iron availability. The mycma_1113 gene expression was also increased after macrophage or in vivo infection indicating that mycobactin synthesis by Mycma could participate in the Fe sequestration from the host during infection. In conclusion, we show that Mycma produces siderophores under iron deprivation conditions and that the mycma_1113 gene is involved in this process, furthermore, this gene expression is induced during infection.