Short Pretreatment with Calcitriol Is Far Superior to Continuous Treatment in Stimulating Proliferation and Osteogenic Differentiation of Human Adipose Stem Cells

16S rDNA analysis of osteoporotic rats treated with osteoking

Introduction. Osteoporosis (OP) is characterized by microstructural degeneration of bone tissue, low bone mass, bone fragility and even brittle fracture (osteoporotic fracture, OPF). OP and OPF are common and there are many disadvantages to the current medications for OP/OPF. Osteoking is a traditional Chinese medicine (TCM) originating from the Yi nationality (Yunnan, China) that has been used to treat bone diseases for decades.Hypothesis/Gap Statement. This study will reveal the changes in the intestinal microbiota of OP rats after 70 days of osteoking treatment.Method. With duplication of sham and OP rats, eight groups were established, with six rats in each group. The intestinal microbiotas were analysed by 16S rDNA sequencing.Results. The results showed that osteoking changed the intestinal microbiota of sham rats and OP rats. The mechanism by which osteoking improves OP is related to the functions of the intestinal microbiota. After 70 days of treatment with osteoking, the contents of Pseudonocardia, Pedomicrobium, Variovorax, Niastella and Actinosynnema were decreased in OP rats. The functions of the above intestinal microbiota related to iron metabolism affected calcifediol and 25(OH)D, and measuring these bone metabolic indicators is required for further study.Conclusion. Osteoking changes the intestinal microbiota to improve OP, and further study which reveals these intestinal microbiota and mechanism is needed.

Osteogenic and Angiogenic Synergy of Human Adipose Stem Cells and Human Umbilical Vein Endothelial Cells Cocultured in a Modified Perfusion Bioreactor

Synergistic promotion of angiogenesis and osteogenesis in bone tissue-engineered constructs remains a crucial clinical challenge, which might be overcome by simultaneous employment of superior techniques including coculture systems, differentiation-stimulated factors, combinatorial scaffolds and bioreactors.Current study investigated the effect of flow perfusion along with coculture of human adipose stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs) on osteogenic and angiogenic differentiation.Pre-treated hASCs with 1,25-dihydroxyvitamin D₃ were seeded onto poly(lactic-co-glycolic acid)/β-tricalcium phosphate/polycaprolactone (PLGA/β-TCP/PCL) scaffold with/without HUVECs, and cultured for 14 days within a flask or modified perfusion bioreactor. Analysis of osteogenic and angiogenic gene expression, alkaline phosphatase (ALP) activity and ALP staining indicates a synergistic effect of perfusion flow and coculture system on osteogenic and angiogenic differentiation. The advantage of modified perfusion bioreactor is its five-branch flow distributor which directly connect to the porous PCL hollow fibers embedded in the 3D scaffold to improve flow and flow-induced shear stress uniformity.Dynamic coculture increased VEGF₁₆₅ by 6-fold, VEGF₁₈₉ by 2-fold, and Endothelin-1 by 4-fold, relative to dynamic monoculture. Static coculture enhanced osteogenic and angiogenic differentiation, compared with static monoculture. Although dynamic coculture is in preference to static coculture due to significant increase in ALP activity and promoted angiogenic marker expression. Our finding is the first to indicate that the modified perfusion bioreactor combined with the beneficial cell-cell crosstalk in pre-treated hASC/HUVEC cocultures provides a synergy between osteogenic and angiogenic differentiation of the accumulation of cells, suggesting that it represents a promising approach for regeneration of critical-sized bone defects.

Burst, Short, and Sustained Vitamin D3 Applications Differentially Affect Osteogenic Differentiation of Human Adipose Stem Cells

Incorporation of 1,25(OH)₂ vitamin D₃ (vitD₃) into tissue-engineered scaffolds could aid the healing of critical-sized bone defects. We hypothesize that shorter applications of vitD₃ lead to more osteogenic differentiation of mesenchymal stem cells (MSCs) than a sustained application. To test this, release from a scaffold was mimicked by exposing MSCs to exactly controlled vitD₃ regimens. Human adipose stem cells (hASCs) were seeded onto calcium phosphate particles, cultured for 20 days, and treated with 124 ng vitD₃, either provided during 30 min before seeding ([200 nM]), during the first two days ([100 nM]), or during 20 days ([10 nM]). Alternatively, hASCs were treated for two days with 6.2 ng vitD₃ ([10 nM]). hASCs attached to the calcium phosphate particles and were viable (~75%). Cell number was not affected by the various vitD₃ applications. VitD₃ (124 ng) applied over 20 days increased cellular alkaline phosphatase activity at Days 7 and 20, reduced expression of the early osteogenic marker RUNX2 at Day 20, and strongly upregulated expression of the vitD₃ inactivating enzyme CYP24. VitD₃ (124 ng) also reduced RUNX2 and increased CYP24 applied at [100 nM] for two days, but not at [200 nM] for 30 min. These results show that 20-day application of vitD₃ has more effect on hASCs than the same total amount applied in a shorter time span.