Hyphae of Rhizopus arrhizus and Lichtheimia corymbifera Are More Virulent and Resistant to Antifungal Agents Than Sporangiospores In Vitro and in Galleria mellonella.

Mucorales species cause debilitating, life-threatening sinopulmonary diseases in immunocompromised patients and penetrating wounds in trauma victims. Common antifungal agents against mucormycosis have significant toxicity and are often ineffective. To evaluate treatments against mucormycosis, sporangiospores are typically used for in vitro assays and in pre-clinical animal models of pulmonary infections. However, in clinical cases of wound mucormycosis caused by traumatic inoculation, hyphal elements found in soil are likely the form of the inoculated organism. In this study, Galleria mellonella larvae were infected with either sporangiospores or hyphae of Rhizopus arrhizus and Lichtheimia corymbifera. Hyphal infections resulted in greater and more rapid larval lethality than sporangiospores, with an approximate 10-16-fold decrease in LD50 of hyphae for R. arrhizus (p = 0.03) and L. corymbifera (p = 0.001). Liposomal amphotericin B, 10 mg/kg, was ineffective against hyphal infection, while the same dosage was effective against infections produced by sporangiospores. Furthermore, in vitro, antifungal susceptibility studies show that minimum inhibitory concentrations of several antifungal agents against hyphae were higher when compared to those of sporangiospores. These findings support using hyphal elements of Mucorales species for virulence testing and antifungal drug screening in vitro and in G. mellonella for studies of wound mucormycosis.

Cellular Senescence in Aging, Tissue Repair, and Regeneration.

SUMMARY: Society and our healthcare system are facing unprecedented challenges due to the expansion of the older population. As plastic surgeons, we can improve care of our older patients through understanding the mechanisms of aging that inevitably impact their outcomes and well-being. One of the major hallmarks of aging, cellular senescence, has recently become the focus of vigorous research in academia and industry. Senescent cells, which are metabolically active but in a state of stable cell cycle arrest, are implicated in causing aging and numerous age-related diseases. Further characterization of the biology of senescence revealed that it can be both detrimental and beneficial to organisms depending on tissue context and senescence chronicity. Here, we review the role of cellular senescence in aging, wound healing, tissue regeneration, and other domains relevant to plastic surgery. We also review the current state of research on therapeutics that modulate senescence to improve conditions of aging.

Elevated skin senescence in young mice causes delayed wound healing.

Although there is growing evidence that cellular senescence influences wound healing, a clear understanding of how senescence can be beneficial and/or detrimental to wound healing is unknown. Wound healing may also be influenced by the baseline tissue senescence, which is elevated in aging and chronic wounds, both of which have significant healing delays. To study the effects of skin senescence on wound healing, we developed an elevated skin senescence model based on the subcutaneous transfer of irradiated fibroblasts into young 8-week-old wild-type C57BL/6 male mice. This senescent cell transfer significantly increased skin senescence levels compared to control transfers of non-irradiated fibroblasts. There was an increased presence of SA-ß-Gal- and p21-positive senescent cells throughout the skin. Furthermore, the entire skin showed significantly elevated gene expression of senescence (p16, p21) and SASP markers (IL-6, MCP-1, MMP-3, MMP-9, and TGF-ß). Subsequent wound healing in the skin with elevated senescence was markedly delayed and had similar kinetics to naturally aged 2-year-old mice. After the wounds had healed, the skin developed persistently elevated senescence. Our results demonstrate that states of elevated skin senescence can delay wound healing and result in sustained senescence after healing. Therefore, the accumulation of senescent cells in aged skin or chronic wounds may be a driver of delayed healing and can be considered a potential target to improve healing.

Lobelia trigona Roxb-based nanomedicine with enhanced biological applications: in vitro and in vivo approach.

This is the first study to report the green synthesis of Lobelia trigona Roxb-mediated silver nanoparticles (LTAgNPs). The optical and structural properties of the synthesised LTAgNPs were analysed using ultraviolet-visible spectroscopy, scanning electron microscopy, Fourier transform infrared, dynamic light scattering and energy dispersive X-ray. LTAgNps were evaluated for their anti-bacterial and anti-fungal properties against 18 pathogens and exhibited significant inhibition against all the strains tested. LTAgNPs had potential scavenging effects on the DPPH, •OH, O2•- free radical scavenging assays and reducing power assay. LTAgNps possess strong anti-cancer activity against five human cancer cell lines (A549, MCF-7, MDA-MB-231, HeLa and KB) in a dose-dependent manner. The antiproliferative, anti-inflammatory and genotoxicity effects of LTAgNPs were further confirmed by the lactate dehydrogenase release assay, nitric oxide inhibitory assay and comet assay. Furthermore, the incision, excision and burn wound-healing activity of formulated LTAgNPs ointment was assessed in rats. All the wounds had significant healing in groups treated with LTAgNPs ointment compared to the groups treated with the commonly prescribed ointment (SilverexTM). This study shows and suggests that the previously unreported LTAgNPs could be used as a nanomedicine with significant biological applications.

Efficacy of Lobelia alsinoides Lam ethanolic extract on a third-degree burn: An experimental study on rats.

This is the first study to evaluate the topical application of Lobelia alsinoides Lam (LT) ethanolic extract on burns in rats. A deep third-degree burn wound was inflicted in adult male Wistar rats and the burns were dressed daily with a topical ointment formulation (Patent filed) comprising of Lobelia alsinoides Lam (5% and 10% w/w). The wound had noteworthy contraction and quicker eschar removal in 10% w/w LT-treated groups followed by 5% w/w treated groups on comparing with the commonly prescribed ointment (SilverexTM containing 1% w/w Silver sulfadiazine). Histopathological analysis showed that ointment containing 10% w/w LT ethanolic extract significantly increased fibroblast growth, which plays a major role in anatomic integrity, collagen synthesis, and accelerated the rate of the healing process. This study shows that the ethanolic extract of Lobelia alsinoides Lam, a previously pharmacologically unreported traditional medicinal plant, possesses wound contraction and eschar removal properties on burn wounds.