We regulated the amount of trehalose and combined it with glycerol to achieve unusually low glycerol concentrations in the cryopreservation of RBCs compared with traditional methods.

Cryopreservation of red blood cells (RBCs) has been studied as a typical example of cryobiology methodology. To date, a mature and long-term cryopreservation process for RBCs has been developed, which has the weakness of complicated procedures due to high concentrations of glycerol (Gly). Therefore, it is still a research focus to find a new method for cryopreservation of RBCs to reduce the concentrations of cryoprotectants (CPAs). In this study, alginate hydrogels, which have been widely used in preservation research, were selected because of their advantages such as lower cost, cytocompatibility, and crosslinking occurring under mild conditions. With a variety of CPA solutions, the RBC recovery with the cryopreservation of RBCs and RBCladen hydrogel microfibers was compared in different situations. It was found that hydrogel microfiber encapsulation enhances cryopreservation of human RBCs with low concentrations of CPAs. And Gly can be removed by washing directly with a 0.9% sodium chloride solution. This study validated the feasibility of cryopreservation of RBC-laden hydrogel microfibers. It may provide a new and evolving direction for reducing the concentrations of CPAs used in the preservation of RBCs.

Vitrification has become one of the promising cryopreservation methods for biosamples including cells and tissues because the vitreous state reduces the damage of ice crystals to cells. However, besides extremely high cooling rates, routine vitrification protocols require a high concentration of penetrating cryoprotectants (pCPAs, ∼6−8 M), which is toxic for cells and brings trouble when removing pCPAs. Therefore, reducing the concentration of toxic pCPAs in vitrification remains a challenge, and advanced strategies are urgently needed. Hydrogel encapsulation has become one effective method to achieve low-cryoprotectant (CPA) concentration preservation of stem cells with rapid cooling, but there are very few related studies about endothelial cells (ECs). In this study, we achieved pCPA concentration (up to 3 M) vitrification by encapsulating human umbilical vein endothelial cells (HUVECs) into core−shell alginate hydrogel microcapsules. Alginate encapsulation increased HUVEC cryosurvival up to 80%, which is 60% improvement compared to control without encapsulation. Furthermore, two different sizes of capsules (diameter: ∼900 and 400 μm) were produced to explore the effects of microcapsule volume on the cell preservation results, and it was found that larger capsules (∼900 μm) have no significant effect on cell survival while improving encapsulation efficiency. This encapsulation method provides a new strategy for EC preservation and serves as an improvement to optimize the preservation of biosamples.

ImportancePlatelet transfusion is commonly performed in infants to correct severe thrombocytopenia or prevent bleeding. Exploring the associations of platelet transfusion, platelet count (PC), and mean platelet volume (MPV) with intraventricular hemorrhage (IVH) and in-hospital mortality in preterm infants can provide evidence for the establishment of future practices.ObjectivesTo evaluate the associations of platelet transfusion, PC, and MPV with IVH and in-hospital mortality and to explore whether platelet transfusion–associated IVH and mortality risks vary with PC and MPV levels at the time of transfusion.Design, Setting, and ParticipantsThis retrospective cohort study included preterm infants who were transferred to the neonatal intensive care unit on their day of birth and received ventilation during their hospital stay. The study was conducted at a neonatal intensive care unit referral center in Beijing, China, between May 2016 and October 2017. Data were retrieved and analyzed from December 2020 to January 2022.ExposuresPlatelet transfusion, PC, and MPV.Main Outcomes and MeasuresAny grade IVH, severe IVH (grade 3 or 4), and in-hospital mortality.ResultsAmong the 1221 preterm infants (731 [59.9%] male; median [IQR] gestational age, 31.0 [29.0-33.0] weeks), 94 (7.7%) received 166 platelet transfusions. After adjustment for potential confounders, platelet transfusion was significantly associated with mortality (hazard ratio [HR], 1.48; 95% CI, 1.13-1.93; P = .004). A decreased PC was significantly associated with any grade IVH (HR per 50 × 103/μL, 1.13; 95% CI, 1.05-1.22; P = .001), severe IVH (HR per 50 × 103/μL, 1.16; 95% CI, 1.02-1.32; P = .02), and mortality (HR per 50 × 103/μL, 1.74; 95% CI, 1.48-2.03; P < .001). A higher MPV was associated with a lower risk of mortality (HR, 0.83; 95% CI, 0.69-0.98; P = .03). The platelet transfusion–associated risks for both IVH and mortality increased when transfusion was performed in infants with a higher PC level (eg, PC of 25 × 103/μL: HR, 1.20; 95% CI, 0.89-1.62; PC of 100 × 103/μL: HR, 1.40; 95% CI, 1.08-1.82). The platelet transfusion–associated risks of IVH and mortality varied with MPV level at the time of transfusion.Conclusions and RelevanceIn preterm infants, platelet transfusion, PC, and MPV were associated with mortality, and PC was also associated with any grade IVH and severe IVH. The findings suggest that a lower platelet transfusion threshold is preferred; however, the risk of a decreased PC should not be ignored.