Optimisation of skeletal muscle sampling for cultured fat production

Abstract

To produce cultured meat at a commercially-relevant scale, bioprocesses must be robust, standardised and cost-efficient. In this respect, the limited in vitro lifespan of primary cells poses a major challenge, which requires regular cell sourcing by means of biopsy. We have previously shown that muscle-derived fibro-adipogenic progenitor cells (FAPs) represent a promising starting cell type for cultured fat production. These cells proliferate for a high number of population doublings (PDs) in serum-free growth medium. However, with accumulating PDs, FAPs lose their adipogenic differentiation capacity, thereby limiting the amount of cultured fat that can be produced from a given starting sample. Donor animal characteristics, including age, may affect this loss of differentiation. Here, we performed a longitudinal biopsy study to ask whether physiological differences between donor animals are reflected in FAP cell biology, and if this has an effect on loss of FAP differentiation capacity. We sampled twelve Limousin cattle over the first two years of their lives, successfully performing 144 muscle biopsies. Animals younger than six months demonstrated higher FAP yields per gram of muscle tissue, making them ideal donors for cultured fat production, but we observed little difference in the proliferation or differentiation of derived cell cultures. This work also provides valuable insights into the tissue harvesting process, highlighting the need for new, robust and standardised biopsy systems to mitigate contamination risk.