(P09-007-24) Fava Bean Hydrolysate Augments Anabolic Response to Leucine in a Model of Aged Muscle

Objectives: Maintaining skeletal muscle (SkM) function is critical for sustaining general health throughout life, with prolonged deterioration of SkM integrity culminating in the onset of Sarcopenia and comorbid disease. To understand the mechanisms of age related SkM atrophy, in-vitro models that recapitulate the complexities of ageing muscle are required. We propose differentiated human myofibroblasts (DIMS) to be a suitable model for capturing these molecular hallmarks and sought to determine whether a fava bean hydrolysate, clinically proven to promote muscle protein synthesis (MPS), could stimulate components of the mTORC1 pathway in young and aged DIMS. Additionally, we aimed to determine whether combination of fava hydrolysate and leucine would further stimulate this pathway.

Methods: IMR90 fibroblasts were infected with lentivirus for stable expression of the myogenic transcription factor, Myogenic Differentiation 1 (MyoD). Differentiation into young and aged myofibroblasts was achieved with addition of doxycycline. Western blotting was used to detect phosphorylation of mTORC1 pathway proteins including ribosomal S6 (rpS6), and the large neutral amino acid transporter (LAT1). Analysis of variance (ANOVA) between means was performed in Prism™.

Results: Dose response experiments in young and aged DIMS showed significant phosphorylation of rpS6 following treatment with fava bean hydrolysate at concentrations from 5µg-50µg/ml compared to basal medium (P < 0.05). Leucine treatments failed to show any significant increase across all concentrations (130µg-1950µg/ml). In young DIMS, combinatorial treatment with fava hydrolysate (0.05µg/ml) and leucine (130µg/ml) caused a 3-fold increase in rpS6 phosphorylation relative to leucine alone. Aged DIMS demonstrated a similar trend, with combined treatment causing a 2-fold increase. Interestingly, basal expression of LAT1 component proteins were found to be significantly reduced in aged relative to young DIMs (P < 0.5).

Conclusions: We show that fava bean hydrolysate elicits phosphorylation of key proteins involved in MPS and identify how combination of fava hydrolysate and leucine augments these effects in young and aged DIMS. Additionally, we show marked reductions in LAT1 expression in aged DIMS, highlighting a potential target for exploring age related muscle loss.

Funding Sources: Nuritas Ltd.