The microenvironment plays an important role in the homing in and differentiation of stem cells to repair injured tissue. Infrapatellar fat pad stromal cells (IFPSCs) are a promising source of such cells for the repair of articular injury-induced degeneration. This study investigated the chemotaxis of IFPSCs to chondrocytes and the effect of hyaluronan (HA) on the biological and regenerative properties of IFPSCs. The IFPSCs were obtained from patients undergoing arthroscopy and cultured via a standard 2-week culture protocol that yielded more than 10 million cells on passage 3. The results showed that the IFPSCs had a higher capacity for chondrogenic differentiation than mesenchymal cells from body fat, bone marrow, and Wharton's jelly of the umbilical cord. The IFPSCs cultured on 25% or 50% HA showed better osteogenic and adipogenic capabilities than those without HA or with 75% HA (p < 0.001). Cultures of the IFPSCs on 25% HA had a fourfold increase in chondrogenic differentiation compared to cultures without HA, which was better than with 50% and 75% HA (p < 0.05). Cell proliferation was not affected by the presence of HA. In conclusion, IFPSCs have a strong potential for chondrogenic regeneration, which can even be augmented in a 25% HA microenvironment.

This study provides a quantitative analysis of the active movements of the chick embryo and of the contractions of the amnion over the entire developmental period of 21 days. Four types of embryo movements are distinguished. The motor activity of the embryo shows two characteristic peaks, with maximum contraction frequencies on the 12th and on the 16th day. In contrast, the amnion activity is higher at earlier stages and decreases as the body activity increases. The amnion activity is largely independent of the body activity. Illumination has a strong influence on embryo movements. It is shown that increases of light intensity affect the patterns of activity of both the embryo and the amnion. While the effect of light on the embryo can be interpreted as being transmitted via the optic system, the mechanism of the amniotic response is unclear. The results suggest that the amnion itself may be sensitive to light. J. Exp. Zool. (Mol. Dev. Evol.) 291:186-194, 2001.

Osteoarthritis is a chronic degenerative joint disorder characterized by articular cartilage destruction and osteophyte formation. Chondrocytes in the matrix have a relatively slow turnover rate, and the tissue itself lacks a blood supply to support repair and remodeling. Researchers have evaluated the effectiveness of stem cell therapy and tissue engineering for treating osteoarthritis. All sources of stem cells, including embryonic, induced pluripotent, fetal, and adult stem cells, have potential use in stem cell therapy, which provides a permanent biological solution. Mesenchymal stem cells (MSCs) isolated from bone marrow, adipose tissue, and umbilical cord show considerable promise for use in cartilage repair. MSCs can be sourced from any or all joint tissues and can modulate the immune response. Additionally, MSCs can directly differentiate into chondrocytes under appropriate signal transduction. They also have immunosuppressive and anti-inflammatory paracrine effects. This article reviews the current clinical applications of MSCs and future directions of research in osteoarthritis.

Aim This study investigated the risk of osteoporosis or bone fractures (vertebrae, hip and others) in hysterectomized women in Taiwan. Materials and methods This is a retrospective population-based cohort study from 2000 to 2013. Women aged ≥30 years who underwent hysterectomy between 2000 and 2012 were included in this study. The comparison group was randomly selected from the database with a 1:4 matching with age and index year. Incidence rate and hazard ratios of osteoporosis and bone fracture between hysterectomized women and the comparison group were calculated. Cox proportional hazard regressions were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Results We identified 9,189 hysterectomized women and 33,942 age-matched women without a hysterectomy. All women were followed for a median time of about 7 years. The adjusted hazard ratio (aHR) of subsequent osteoporosis or bone fracture was higher in the hysterectomy women (2.26, 95% confidence interval [CI] = 2.09–2.44) than in the comparison group. In the subgroup analysis, oophorectomy and estrogen therapy increase the risk of osteoporosis or fracture in both groups. Regarding the fracture site, the aHR of vertebral fracture (4.92, 95% CI = 3.78–6.40) was higher in the hysterectomized women than in the comparison group. As follow-up time increasing, the aHR of vertebral fracture in hysterectomized women were 4.33 (95% CI = 2.99–6.28), 3.89 (95% CI = 2.60–5.82) and 5.42 (95% CI = 2.66–11.01) for <5, 5–9 and ≥9 years of follow-up, respectively. Conclusions In conclusion, we found that hysterectomized women might be associated with increased risks of developing osteoporosis or bone fracture.

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Objectives:Osteoarthritis (OA) is a chronic disease of degenerative joints. Mesenchymal stem cells (MSCs) have been used for cartilage regeneration in OA. We investigated the therapeutic potential of human umbilical cord-derived MSCs (HUCMSCs) with hyaluronic acid (HA) hydrogel transplanted into a porcine OA preclinical model.Materials and Methods:The HUCMSCs were characterized with respect to morphology, surface markers, and differentiation capabilities. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was used to examine gene expressions in a HUCMSC–HA coculture. Two healthy female minipigs weighing 30–40 kg and aged approximately 4 months were used in this large animal study. A full-thickness chondral injury was created in the trochlear groove of each of the pig's rear knees. After 3 weeks, a second osteochondral defect was created. Then, 1.5 mL of a HUCMSC (5 × 106 cells) and HA composite (4%) was transplanted into the chondral-injured area in the right knee of each pig. Using the same surgical process, an osteochondral defect (untreated) was created in the left knee as a control. The pigs were sacrificed 12 weeks after transplantation. Macroscopic and microscopic histologies, qRT-PCR, and immunostaining evaluated the degree of chondral degradation.Results:The HUCMSCs exhibited typical MSC characteristics, including spindle morphology, expression of surface markers (positive for CD29, CD4, CD73, CD90, and human leukocyte antigen [HLA]-ABC; negative for CD34, CD45, and HLA-DR), and multipotent differentiation (adipogenesis, osteogenesis, and chondrogenesis). More extensive proliferation of HUCMSCs was noted with 4% and 25% of HA than without HA. Expression of COL2A1 and aggrecan in the HUCMSC-derived chondrocytes was increased when HA was included. The treated knees showed significant gross and histological improvements in hyaline cartilage regeneration when compared to the control knees. The International Cartilage Repair Society histological score was higher for the treated knees than the control knees.Conclusion:Our findings suggest that cartilage regeneration using a mixture of HUCMSCs and HA in a large animal model may be an effective treatment for OA, and this study is a stepping stone toward the future clinical trials.

The aim of this study was to explore the therapeutic effect of iPSC-mesenchymal stem cell (MSC)-derived chondrocytes in a rabbit osteoarthritis (OA) model. The iPSCs were characterized by gene expressions, immunostaining of pluripotent markers, and in vivo teratoma formation. iPSC-differentiated MSCs were characterized by flow cytometry and trilineage differentiation. A rabbit OA model was established by the transection of the anterior cruciate ligament. The therapeutic effect of transplanted iPSC-MSC-chondrocytes on the OA was evaluated by the histology, immunostaining, and qPCR of defective cartilage. The results showed iPSC could express pluripotency markers such as OCT4, SOX2, and NANOG and form an embryoid body and a teratoma. After differentiation of iPSCs for 30 days, MSCs were established. The iPSC-MSC could express typical MSC markers such as CD29, CD44, CD90, CD105, and HLA-ABC. They could differentiate into adipocytes, osteocytes, and chondrocytes. In this model, iPSC-MSC-chondrocytes significantly improved the histology and ICRS (International Cartilage Repair Society) scores. The transplanted cartilage expressed less IL-1β, TNF-α, and MMP13 than control cartilage. In conclusion, the iPSCs we derived might represent an emerging source for differentiated MSC-chondrocyte and might rescue cartilage defects through its anti-inflammatory and anti-catabolic effects.