Mesenchymal stem cell (MSC)‐derived extracellular vesicles (EVs) have emerged as potential therapeutic agents for numerous applications. EVs offer potential advantages over cell‐based therapies with regard to safety, stability and clearance profiles, however production and potency limitations must be addressed to enable eventual translation of EV‐based approaches. Thus, we sought to examine the role of specific cell culture parameters on MSC EV production and bioactivity toward informing rational design parameters for scalable EV biomanufacturing. We report significantly reduced MSC EV vascularization bioactivity, as measured by an endothelial cell gap closure assay, with increasing passage in culture by trypsinization, especially beyond passage 4. We further show that increased frequency of EV collection yielded higher numbers of EVs from the same initial number of MSCs over a 24 hr period. Finally, we demonstrate that decreased cell seeding density in culture flasks resulted in increased production of EVs per cell in MSCs and other cell types. Overall, these studies highlight the need for careful consideration of the parameters of cell passage number and cell seeding density in the production of therapeutic EVs at laboratory scale and for rational design of large‐scale EV biomanufacturing schemes.

Objective: Infants receiving parenteral nutrition (PN) are at increased risk of PN-associated liver disease (PNALD), which can lead to hepatic fibrosis. Congenital heart disease (CHD) represents a risk factor for hepatic fibrosis, so this study sought to better understand whether infants with CHD were at elevated risk of PNALD when receiving long-term PN.Study Design: This study includes a retrospective cohort of infants at a level IV neonatal intensive care unit from 2010 to 2020 who received long-term PN during the first 8 weeks of life. A time-varying Cox survival model was used to model risk of PNALD between infants with and without CHD, adjusted for demographics, surgical intervention, and PN exposure, using a 5000-iteration bootstrap estimation.Secondary analyses evaluated risk against discrete CHD diagnoses, and sensitivity analysis was performed on the magnitude and quantity of direct bilirubin laboratory measurements making up the PNALD definition.Results: Neonates with CHD were found to be at higher risk for PNALD during or soon after long-term PN exposure. A pattern of increasing association strength with increasing bilirubin threshold suggests infants with CHD may also experience higher degrees of injury.Conclusions: This work offers a step in understanding how diagnoses can be factored into neonate PN prescription. Future work will explore modifications in lipid profiles and timing to mitigate risk in patients with CHD.

Objective: Infants receiving parenteral nutrition (PN) are at increased risk of PN associated liver disease (PNALD) which can manifest in hepatic fibrosis. While congenital heart disease (CHD) represents a risk factor for hepatic fibrosis, this study sought to better understand if infants with CHD were at elevated risk of PNALD when receiving long-term PN. Study Design: A retrospective cohort of infants at a Level-IV NICU 2010-2020 who received long-term PN during the first 8-weeks of life. A 5000-iteration bootstrap estimation for time-varying cox-survival model was used to model risk of PNALD adjusted for demographics and PN exposure. Results: Neonates with CHD were found to be at higher risk for PNALD during or quickly following long-term PN exposure. Conclusions: This work offers a step in understanding how diagnoses can be factored into neonate PN prescription. Future work will explore lipid profiles and timing to mitigate risk in patients with CHD.