Physiologically-obtainable polyphenol exposures modulate reactive oxygen and nitrogen species signaling in the C2C12 model of skeletal muscle ageing.

Age-related frailty is a significant health and social care burden, with limited treatment options. There is a lack of suitable cell culture model for screening large numbers of test compounds to identify those which promote healthy skeletal muscle function. This paper describes the characterization of reactive oxygen and nitrogen species (RONS) signalling changes in young and aged myoblasts and myotubes using C2C12 cells, and the application of aged cultures to assess the effect of dietary polyphenols on RONS signalling. Aged myoblasts and myotubes showed significantly increased reactive oxygen species (p < 0.01 and p < 0.001 respectively), nitric oxide (p < 0.05 for myoblasts and myotubes), and lipid peroxidation (p < 0.05 for myoblasts and myotubes). Nine polyphenols were assessed in aged myoblasts and myotubes using concentrations and incubation times consistent with known pharmacokinetic parameters for these compounds. Although several polyphenols were seen to reduce single markers of RONS signalling, only kaempferol and resveratrol significantly reduced multiple markers in both cell models. Modulation of enzymatic antioxidant activities was assessed as a possible mechanism of action, although superoxide dismutase and catalase activities were significantly reduced in aged (versus young) myotubes (p < 0.01 and p < 0.05 respectively), no effect of polyphenol treatment on these enzyme activities were observed. Overall, this research has shown the utility of the C2C12 model (myoblasts and myotubes) for screening compounds in aged muscle, and that resveratrol and kaempferol (using pharmacokinetically-informed exposures) can modulate RONS signalling in skeletal muscle cells after an acute exposure.

Co-Loading of Black Phosphorus Nanoflakes and Doxorubicin in Lysolipid Temperature-Sensitive Liposomes for Combination Therapy in Prostate Cancer.

Black phosphorus (BP) is one of the most promising nanomaterials for cancer therapy. This 2D material is biocompatible and has strong photocatalytic activity, making it a powerful photosensitiser for combined NIR photothermal and photodynamic therapies. However, the fast degradation of BP in oxic conditions (including biological environments) still limits its use in cancer therapy. This work proposes a facile strategy to produce stable and highly concentrated BP suspensions using lysolipid temperature-sensitive liposomes (LTSLs). This approach also allows for co-encapsulating BP nanoflakes and doxorubicin, a potent chemotherapeutic drug. Finally, we demonstrate that our BP/doxorubicin formulation shows per se high antiproliferative action against an in vitro prostate cancer model and that the anticancer activity can be enhanced through NIR irradiance.