BACKGROUND: Knee osteoarthritis (KOA) is a prevalent chronic joint disease caused by various factors. Mesenchymal stem cells (MSCs) therapy is an increasingly promising therapeutic option for osteoarthritis. However, the chronic inflammation of knee joint can severely impede the therapeutic effects of transplanted cells. Gelatin microspheres (GMs) are degradable biomaterial that have various porosities for cell adhesion and cell–cell interaction. Excellent elasticity and deformability of GMs make it an excellent injectable vehicle for cell delivery. METHODS: We created Wharton’s jelly derived mesenchymal stem cells (WJMSCs)-GMs complexes and assessed the effects of GMs on cell activity, proliferation and chondrogenesis. Then, WJMSCs loaded in GMs were transplanted in the joint of osteoarthritis mice. After four weeks, joint tissue was collected for histological analysis. Overexpressing-luciferase WJMSCs were performed to explore cell retention in mice. RESULTS: In vitro experiments demonstrated that WJMSCs loaded with GMs maintained cell viability and proliferative potential. Moreover, GMs enhanced the chondrogenesis differentiation of WJMSCs while alleviated cell hypertrophy. In KOA mice model, transplantation of WJMSCs-GMs complexes promoted cartilage regeneration and cartilage matrix formation, contributing to the treatment of KOA. Compared with other groups, in WJMSCs+GMs group, there were fewer cartilage defects and with a more integrated tibia structure. Tracking results of stable-overexpressing luciferase WJMSCs demonstrated that GMs significantly extended the retention time of WJMSCs in knee joint cavity. CONCLUSION Our results indicated that GMs facilitate WJMSCs mediated knee osteoarthritis healing in mice by promoting cartilage regeneration and prolonging cell retention. It might potentially provide an optimal strategy for the biomaterial-stem cell based therapy for knee osteoarthritis.

Objective:To compare the endometrial blood flow in patients with recurrent implantation failure (RIF) and non RIF patients.Methods:A prospective cohort study was perfomed. Infertility patients who underwent frozen-thawed embryo transfer (FET) cycles in the Reproductive Medicine Center of the First Affiliated Hospital of Sun Yat-Sen University from February 2019 to July 2019 were included. Transvaginal color Doppler ultrasound was used to detect whether there was subendometrial blood flow in the endometrium of RIF patients (RIF group, n=85) and non-RIF patients (non-RIF group, n=17). The proportion of patients without endometrial blood flow signal was compared, as well as endometrial blood flow pulsatility index (PI) and resistance index (RI). Results:Compared with non-RIF group, the proportion of patients without endometrial blood flow signal detected by ultrasound was significantly increased in RIF group [34.12% (29/85) vs. 5.88% (1/17), P=0.020]. PI and RI values of RIF group were significantly higher than those of non-RIF group (0.895 9±0.182 0 vs. 0.779 1±0.271 9, P=0.048; 0.575 6±0.078 4 vs. 0.511 1±0.130 7, P=0.016). Univariate logistic regression analysis showed that endometrial blood flow was an independent risk factors for RIF ( P=0.045). Conclusion:Abnormal endometrial blood flow may be related to RIF, which may cause RIF by reducing the receptivity of endometrium to embryo.

Objective:To compare the endometrial blood flow in patients with recurrent implantation failure (RIF) and non RIF patients.Methods:A prospective cohort study was perfomed. Infertility patients who underwent frozen-thawed embryo transfer (FET) cycles in the Reproductive Medicine Center of the First Affiliated Hospital of Sun Yat-Sen University from February 2019 to July 2019 were included. Transvaginal color Doppler ultrasound was used to detect whether there was subendometrial blood flow in the endometrium of RIF patients (RIF group, n=85) and non-RIF patients (non-RIF group, n=17). The proportion of patients without endometrial blood flow signal was compared, as well as endometrial blood flow pulsatility index (PI) and resistance index (RI). Results:Compared with non-RIF group, the proportion of patients without endometrial blood flow signal detected by ultrasound was significantly increased in RIF group [34.12% (29/85) vs. 5.88% (1/17), P=0.020]. PI and RI values of RIF group were significantly higher than those of non-RIF group (0.895 9±0.182 0 vs. 0.779 1±0.271 9, P=0.048; 0.575 6±0.078 4 vs. 0.511 1±0.130 7, P=0.016). Univariate logistic regression analysis showed that endometrial blood flow was an independent risk factors for RIF ( P=0.045). Conclusion:Abnormal endometrial blood flow may be related to RIF, which may cause RIF by reducing the receptivity of endometrium to embryo.