In this study published in the journal Nutrition Research, researchers from Sungkyunkwan University in South Korea investigated the proliferative effect of apple ethanol extract on human adipose tissue-derived mesenchymal stem cells (ADSCs) and human cord blood-derived mesenchymal stem cells (CB-MSCs). They also identified the possible molecular mechanisms behind its beneficial effects.

• Tissue regeneration using adult stem cells (ASCs) has significant potential as a novel treatment for many degenerative diseases.
• According to previous studies, age negatively affects the proliferation status and differentiation potential of ASCs, suggesting a possible limitation in their potential therapeutic use.
• The researchers hypothesized that apple extract might exert beneficial effects on ASCs.
• Through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Click-iT 5-ethynyl-2?-deoxyuridine flow cytometry assays, they found that apple extract promoted the proliferation of ADSCs and CB-MSCs.
• Apple extract also induced the stepwise phosphorylation of p44/42 MAPK (ERK), mammalian target of rapamycin (mTOR), p70 S6 kinase (p70S6K), S6 ribosomal protein (S6RP), eukaryotic initiation factor (eIF) 4B, and eIF4E in ADSCs.
• Furthermore, apple extract significantly induced the production of vascular endothelial growth factor and interleukin-6 in both ADSCs and CB-MSCs.
• Pre-treatment with PD98059, a specific ERK inhibitor, inhibited the phosphorylation of the mTOR/p70S6K/S6RP/eIF4B/eIF4E pathway induced by apple extract.
• The researchers discovered that apple extract-induced proliferation of ADSCs under serum-free conditions is mediated by ERK-dependent cytokine production.

Based on these findings, the researchers concluded that the beneficial effect of apple extract on the proliferation of ASCs may overcome the limitation in their therapeutic use in tissue regeneration and maintenance of stem cell homeostasis.

Journal Reference:

Lee J, Shin MS, Kim MO, Jang S, Oh SW, Kang M, Jung K, Park YS, Lee J. APPLE ETHANOL EXTRACT PROMOTES PROLIFERATION OF HUMAN ADULT STEM CELLS, WHICH INVOLVES THE REGENERATIVE POTENTIAL OF STEM CELLS. Nutrition Research. September 2016;36(9):925–936. DOI: 10.1016/j.nutres.2016.06.010