Dose-dependent effects of vitamin D on transdifferentiation of skeletal muscle cells to adipose cells

Fat infiltration within muscle is one of a number of features of vitamin D deficiency, which leads to a decline in muscle functionality. The origin of this fat is unclear, but one possibility is that it forms from myogenic precursor cells present in the muscle, which transdifferentiate into mature adipocytes. The current study examined the effect of the active form of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), on the capacity of the C2C12 muscle cell line to differentiate towards the myogenic and adipogenic lineages. Cells were cultured in myogenic or adipogenic differentiation media containing increasing concentrations (0, 10−13, 10−11, 10−9, 10−7 or 10−5 M) of 1,25(OH)2D3 for up to 6 days and markers of muscle and fat development measured. Mature myofibres were formed in both adipogenic and myogenic media, but fat droplets were only observed in adipogenic media. Relative to controls, low physiological concentrations (10−13 and 10−11 M) of 1,25(OH)2D3 increased fat droplet accumulation, whereas high physiological (10−9 M) and supraphysiological concentrations (≥10−7 M) inhibited fat accumulation. This increased accumulation of fat with low physiological concentrations (10−13 and 10−11 M) was associated with a sequential up-regulation of PPARγ2 (PPARG) and FABP4 mRNA, indicating formation of adipocytes, whereas higher concentrations (≥10−9 M) reduced all these effects, and the highest concentration (10−5 M) appeared to have toxic effects. This is the first study to demonstrate dose-dependent effects of 1,25(OH)2D3 on the transdifferentiation of muscle cells into adipose cells. Low physiological concentrations (possibly mimicking a deficient state) induced adipogenesis, whereas higher (physiological and supraphysiological) concentrations attenuated this effect

Challenging the business case logic for sustainability as an instrument of CSR: Do consumer attitudes in Germany support a business case?

Abstract Purpose: The overall goal of this paper is to critique the purported business case for CSR and sustainability, which persists as a major contentious force in convincing companies to become more sustainable. Extant literature on sustainability, CSR and Socially Responsible Investments (SRIs) generally tends to focus on company perspectives decision-making and approaches. This paper considers an alternative and under-developed perspective and examines CSR from a consumer/ public perspective situ-ated in a German context. Methodology/approach: This paper builds a comprehensive literature review and employs a research philo-sophical point of view underpinned by a social constructionist stance. It examines indicators and attitudes towards sustainability and sustainable consumption together with socially responsible investments and considers whether the buying patterns of German consumers may serve as a rationalisation for a potential business case for CSR and sustainability. Findings: While the awareness of consumers of CSR in Germany towards sustainability tends to be generally relatively prima facie high, it is nevertheless noticeable that German consumers are predominately reluctant to pay a price premium for product possessing a superior sustainability performance. From the alternative lens of SRIs, rather than being a replete and widespread phenomenon, they are still largely a niche market.. For these reasons, the potential for the existence of a business case for sustainability, CSR and SRIs tends, in reality to be low, in spite of some populist or survey reports and perceptions. Originality/value of paper: The paper links a consumer perspective with the business case for CSR. Moreover, it focuses on the German context with tends to be underrepresented in international research. Keywords: Business Case, CSR, Sustainable Development, Sustainable Consump-tion, SRIs, German