Improved Preservation Outcomes of Cluster of Differentiation 34+ Stem Cells in Cord Blood following long-Term Storage at Ultra-low Temperature

Abstract

Background: Umbilical cord blood is a rich source of Cluster of Differentiation (CD) 34 + stem cells with therapeutic value, but its use in Nigeria is limited due to inadequate cryopreservation infrastructure and underdeveloped cord blood banking systems. Objective: This study aimed to assess the viability of CD34 + stem cells in cord blood after long-term storage at ultra-low temperature. Methods: In this longitudinal study, cord blood was collected and cryopreserved at −190°C in a liquid nitrogen tank. CD34 + stem cell viability was assessed biweekly over 48 weeks using flow cytometry. Data were analyzed with SPSS to evaluate viability trends and predict future cell preservation. Results: Fifty postpartum women (mean age: 32.4 ± 5.91 years) participated. Baseline CD34 + counts averaged 330 cells/µL, declining steadily to about 220 cells/µL over 48 weeks. Forecasting predicts a continued gradual decline, with viability potentially lost after approximately 200 weeks if current trends persist. Conclusion: CD34 + stem cells remain viable after 48 weeks at −190°C, with viability expected beyond 3 years, confirming the effectiveness of ultra-low-temperature storage. This demonstrates the potential for sustainable cord blood banking in Nigeria, where funding is limited for its establishment. To fully realize this opportunity, increased public awareness, healthcare training, supportive policies, and further research on the optimization and clinical application are necessary.