Yingchun Wang

Objective— Apheresis platelets for transfusion treatment are currently stored at room temperature because after refrigeration platelets are rapidly cleared on transfusion. In this study, the role of von Willebrand factor (VWF) in the clearance of refrigerated platelets is addressed. Approach and Results— Human and murine platelets were refrigerated in gas-permeable bags at 4°C for 24 hours. VWF binding, platelet signaling events, and platelet post-transfusion recovery and survival were measured. After refrigeration, the binding of plasma VWF to platelets was drastically increased, confirming earlier studies. The binding was blocked by peptide OS1 that bound specifically to platelet glycoprotein (GP)Ibα and was absent in VWF − / − plasma. Although surface expression of GPIbα was reduced after refrigeration, refrigeration-induced VWF binding under physiological shear induced unfolding of the GPIbα mechanosensory domain on the platelet, as evidenced by increased exposure of a linear epitope therein. Refrigeration and shear treatment also induced small elevation of intracellular Ca 2+ , phosphatidylserine exposure, and desialylation of platelets, which were absent in VWF −/− platelets or inhibited by OS1, which is a monomeric 11-residue peptide (CTERMALHNLC). Furthermore, refrigerated VWF −/− platelets displayed increased post-transfusion recovery and survival than wild-type ones. Similarly, adding OS1 to transgenic murine platelets expressing only human GPIbα during refrigeration improved their post-transfusion recovery and survival. Conclusions— Refrigeration-induced binding of VWF to platelets facilitates their rapid clearance by inducing GPIbα-mediated signaling. Our results suggest that inhibition of the VWF–GPIbα interaction may be a potential strategy to enable refrigeration of platelets for transfusion treatment.

BACKGROUND: Supraspinatus tendinitis recurs easily after treatment. One of the main reasons is the lack of objective tools for the efficacy evaluation. Shear wave elastography (SWE) can quantitatively analyze the tissue elasticity of region of interest by measuring the Young's modulus (YM) value. AIM: To explore the role of SWE in the efficacy and prognostic evaluation of supraspinatus tendinitis. METHODS: Eighty-seven patients with supraspinatus tendinitis treated in Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health Sciences were recruited. Another 30 healthy volunteers were enrolled as the control group. The visual analogue scale (VAS) and Constant-Murley Score (CMS) were recorded before treatment. All participants were scanned by SWE scan, and the YM value of the region of interest were recorded. Spearman correlation analysis was performed on YM values with VAS and CMS. Univariate repeated measures analysis of variance was used to calculate the changing trend of VAS, CMS and SWE under different treatment courses. After treatment, the patients were further grouped based on who achieved significantly effective and curative treatment. The patients in the continued treatment group continued to receive treatment according to the YM value, and the remaining patients who stopped receiving treatment were included in the stopped treatment group. All patients were followed up for 1 year, and the difference in recurrence rates between the continued treatment group and the stopped treatment group were compared. RESULTS: = 0.007). CONCLUSION: SWE can objectively indicate the severity of supraspinatus tendinitis. Using the YM value as a criterion for curative effect may reduce the recurrence rate.

BACKGROUND: To investigate the effect of low-intensity pulsed ultrasound (LIPUS) combined with lipid microbubbles on the proliferation and bone regeneration of bone marrow mesenchymal stem cells (BMSCs) in poly (lactic-glycolic acid copolymer) (PLGA)/α-tricalcium phosphate (TCP) 3D-printed scaffolds. METHODS: BMSCs were irradiated with different LIPUS parameters and microbubble concentrations, and the best acoustic excitation parameters were selected. The expression of type I collagen and the activity of alkaline phosphatase were detected. Alizarin red staining was used to evaluate the calcium salt production during osteogenic differentiation. RESULTS: sound intensity and 20% duty cycle. After 14 days, the type I collagen expression and alkaline phosphatase activity in the scaffold increased significantly compared to those in the control group, and alizarin red staining showed more calcium salt production during osteogenic differentiation. After 21 days, scanning electron microscopy experiments showed that osteogenesis was obvious in the PLGA/TCP scaffolds. CONCLUSION: LIPUS combined with lipid microbubbles on PLGA/TCP scaffolds can promote BMSCs growth and bone differentiation, which is expected to provide a new and effective method for the treatment of bone regeneration in tissue engineering.