Mesenchymal Stromal Cell Therapy to Prevent Bronchopulmonary Dysplasia in Extreme Preterm Infants

Effects of uc-MSCs on the date of extubation for participants.

This respiratory outcome will be measured to determine if uc-MSCs have an effect on the date of extubation for participants

Time frame: From date of randomization until the date of discharge home or date of death from any cause, whichever came first, assessed up to 12 months

Effects of uc-MSCs on the rate of survival without moderate or severe BPD at 36 weeks corrected age.

This will assess if uc-MSCs impact survival with moderate or severe Bronchopulmonary dysplasia.

Time frame: BPD severity will be assessed for each participant at 36 weeks of corrected age

Effects of uc-MSCs on the Number of Participants receiving open-label dexamethasone for severe chronic lung disease

This will help us determine if the intervention reduces use of dexamethasone for the treatment of severe chronic lung disease.

Time frame: From date of randomization until the date of discharge home or date of death from any cause, whichever came first, assessed up to 12 months

Effects of uc-MSCs on the duration of respiratory support.

Since ventilation damages underdeveloped lungs, determining the duration of ventilation is important to monitor as an outcome of uc-MSCs. We will collect the total number of days on mechanical ventilation, non-invasive ventilation, and oxygen therapy during the NICU hospitalization for each participant

Time frame: From date of randomization until the date of discharge home or date of death from any cause, whichever came first, assessed up to 12 months

Effects of uc-MSCs on the levels of respiratory support at 36 weeks CA, 40 weeks CA and at hospital discharge.

The different levels of intensity of ventilation will help us determine if uc-MSCs reduce ventilation days. The respiratory support being used are the following (Room air being the least intensive and best for participant health outcome.): mechanical ventilation vs. Continuous Positive Airway pressure/High Flow Nasal Canula, vs. Low Flow Nasal Canula vs. room air

Time frame: From date of randomization until the date of discharge home or date of death from any cause, whichever came first, assessed up to 12 months

Effects of uc-MSCs on the occurrence of pulmonary hypertension related to severe BPD

This will help us determine the therapeutic properties of UC-MSCs in reducing the occurrence of pulmonary hypertension related to severe BPD. Participants will be screened by echocardiography for pulmonary hypertension at 36 weeks of corrected age. Medication for chronic pulmonary hypertension will be collected.

Time frame: From date of randomization until the date of discharge home or date of death from any cause, whichever came first, assessed up to 12 months

Neurodevelopment and health outcomes at 24 months corrected age (Bayleys)

The neurodevelopmental assessment will be scheduled at 24 months CA with a window of +/- 6 months (i.e., between 18 to 30 months CA). Participants will be evaluated in the Neonatal Follow-Up clinic for high-risk infants. An assessment of general health and growth will be performed, and the most recent audiology and ophthalmology results will be recorded. The Bayley Scales of Infant Develpment-4th edition will be performed by a qualified professional to further evaluate the neurodevelopment of the participant.

Time frame: Assessment will be scheduled at 24 months corrected age.

Evaluation of safety of IV administration of UC-MSCs: Dose Limiting toxicity

Dose-limiting toxicity, defined as one of the following events, occurring within 24-hour post UC-MSC injection: * Death * Anaphylaxis * Increase need for respiratory support define by increase FiO2 \>30% from baseline and/or increase in mean airway pressure \> 5 cmH2O from baseline * Medications to support hemodynamic status (including management of cardiac arrest) including fluid boluses, inotropes, or vasopressors * Any SAE not expected in this patient population for which there is no alternative explanation but the IV administration of UC-MSCs and occurring within 1 week after UC-MSCs injection.

Time frame: 24-hours post uc-MSC injection

Evaluation of safety of IV administration of UC-MSCs: potential adverse event

Any Serious Adverse Event (SAE) not expected in this patient population for which there is no alternative explanation but the IV administration of UC-MSCs and occurring within 1 week after UC-MSCs injection.

Time frame: within 1 week post uc-MSC injection

Long-term participant safety follow-up

We plan to have annual parental interviews via telephone until the participant is 10 years old. This is to assess the respiratory status and any new diagnoses of study participants.

Time frame: From enrollment until participant is 10 years of age.

Complications of prematurity (assessed at time of hospital discharge)

The complications of prematurity assessed are the following: * BPD. * Patent Ductus Arteriosus requiring medical, surgical or device closure. * Intra-ventricular hemorrhage ≥ grade 3 according to Papille's classification. * Periventricular leukomalacia. * Necrotizing enterocolitis ≥ stage 2 according to Bell's classification. * Retinopathy of prematurity requiring treatment * Late-onset sepsis

Time frame: From date of randomization until the date of discharge home or date of death from any cause, whichever came first, assessed up to 12 months