Stem cell secretome restore the adipo-osteo differentiation imbalance in diabetic dental pulp-derived mesenchymal stem cells.

Background: Mesenchymal stem cells (MSCs) from type 2 diabetes mellitus (T2DM) individuals exhibit increased adipogenesis and decreased osteogenesis. We investigated the potential of adipose tissue-derived MSCs (ADMSCs) secretome obtained from healthy individuals in restoring the tumor necrosis factor-α (TNF-α) mediated imbalance in the adipo/osteogenic differentiation in the dental pulp-derived MSCs obtained from T2DM individuals (dDPMSCs).

Methods: dDPMSCs were differentiated into adipocytes and osteocytes using a standard cocktail in the presence of (a) induction cocktail, (b) induction cocktail + TNF-α, and (c) induction cocktail+ TNF-α + ADMSCs-secretome (50%) for 15 and 21 days resp. Differentiated adipocytes and osteocytes were stained by oil red O and alizarin red and analyzed by using ImageJ software. Molecular expression of the key genes involved was analyzed by using reverse-transcription polymerase chain reaction (RT-PCR).

Results: Treatment of TNF-α augmented the adipogenesis (9571 ± 765 vs. 19,815 ± 1585 pixel,  < 0.01) and decreased the osteogenesis (15,603 ± 1248 vs. 11,894 ± 951 pixel,  < 0.05) of dDPMSCs as evidenced by the oil red O and alizarin red staining respectively. Interestingly, dDPMSCs differentiated along with TNF-α and 50% ADMSCs secretome exhibited enhanced osteogenesis (11,894 ± 951 vs. 41,808 ± 3344 pixel,  < 0.01) and decreased adipogenesis (19,815 ± 1585 vs. 4480 ± 358 pixel,  < 0.01). Additionally, dDPMSCs differentiated along with ADMSCs secretome exhibited decreased expression of PPARg ( < 0.01), C/EBPa ( < 0.05), and FAS ( < 0.01) whereas mRNA expression of Runx2 ( < 0.05), Osterix ( < 0.01), and OCN ( < 0.05) was upregulated as revealed by the RT-PCR analysis.

Conclusion: ADMSCs secretome from healthy individuals restore the TNF-α influenced differentiation fate of dDPMSCs and therefore can be explored for T2DM clinical management in the future.