HIF-1α as a Regulator of BMP2-Induced Chondrogenic Differentiation, Osteogenic Differentiation, and Endochondral Ossification in Stem Cells.

BACKGROUND/AIMS: Joint cartilage defects are difficult to treat due to the limited self-repair capacities of cartilage. Cartilage tissue engineering based on stem cells and gene enhancement is a potential alternative for cartilage repair. Bone morphogenetic protein 2 (BMP2) has been shown to induce chondrogenic differentiation in mesenchymal stem cells (MSCs); however, maintaining the phenotypes of MSCs during cartilage repair since differentiation occurs along the endochondral ossification pathway. In this study, hypoxia inducible factor, or (HIF)-1α, was determined to be a regulator of BMP2-induced chondrogenic differentiation, osteogenic differentiation, and endochondral bone formation. METHODS: BMP2 was used to induce chondrogenic and osteogenic differentiation in stem cells and fetal limb development. After HIF-1α was added to the inducing system, any changes in the differentiation markers were assessed. RESULTS: HIF-1α was found to potentiate BMP2-induced Sox9 and the expression of chondrogenesis by downstream markers, and inhibit Runx2 and the expression of osteogenesis by downstream markers in vitro. In subcutaneous stem cell implantation studies, HIF-1α was shown to potentiate BMP2-induced cartilage formation and inhibit endochondral ossification during ectopic bone/cartilage formation. In the fetal limb culture, HIF-1α and BMP2 synergistically promoted the expansion of the proliferating chondrocyte zone and inhibited chondrocyte hypertrophy and endochondral ossification. CONCLUSION: The results of this study indicated that, when combined with BMP2, HIF-1α induced MSC differentiation could become a new method of maintaining cartilage phenotypes during cartilage tissue engineering.

Retrospective study of effect of whole-body vibration training on balance and walking function in stroke patients.

BACKGROUND: Dysfunction in stroke patients has been a problem that we committed to solve and explore. Physical therapy has some effect to regain strength, balance, and coordination. However, it is not a complete cure, so we are trying to find more effective treatments. AIM: To observe the effect of whole-body vibration training (WVT) on the recovery of balance and walking function in stroke patients, which could provide us some useful evidence for planning rehabilitation. METHODS: The clinical data of 130 stroke participants who underwent conventional rehabilitation treatment in our hospital from January 2019 to August 2020 were retrospectively analyzed. The participants were divided into whole-body vibration training (WVT) group and non-WVT (NWVT) group according to whether they were given WVT. In the WVT group, routine rehabilitation therapy was combined with WVT by the Galileo Med L Plus vibration trainer at a frequency of 20 Hz and a vibration amplitude of 0+ACY-plusmn+ADs-5.2 mm, and in the NWVT group, routine rehabilitation therapy only was provided. The treatment course of the two groups was 4 wk. Before and after treatment, the Berg balance scale (BBS), 3 m timed up-and-go test (TUGT), the maximum walking speed test (MWS), and upper limb functional reaching (FR) test were performed. RESULTS: After 4 wk training, in both groups, the BBS score and the FR distance respectively increased to a certain amount (WVT = 46.08 ± 3.41 vs NWVT = 40.22 ± 3.75; WVT = 20.48 ± 2.23 vs NWVT = 16.60 ± 2.82), with P < 0.05. Furthermore, in the WVT group, both BBS score and FR distance (BBS: 18.32 ± 2.18; FR: 10.00 ± 0.92) increased more than that in the NWVT group (BBS: 13.29 ± 1.66; FR: 6.16 ± 0.95), with P < 0.05. Meanwhile, in both groups, the TUGT and the MWS were improved after training (WVT = 32.64 ± 3.81 vs NWVT = 39.56 ± 3.68; WVT = 12.73 ± 2.26 vs NWVT = 15.04 ± 2.27, respectively), with P < 0.05. The change in the WVT group (TUGT: 17.49 ± 1.88; MWS: 6.79 ± 0.81) was greater than that in the NWVT group (TUGT: 10.76 ± 1.42; MWS: 4.84 ± 0.58), with P < 0.05. CONCLUSION: The WVT could effectively improve the balance and walking function in stroke patients, which may be good for improving their quality of life.