The influence of pH and pCO2 levels of umbilical cord blood obtained perinatally on selected parameters of stem cells

OBJECTIVE: The aim of the study was to demonstrate a correlation between pH and pCO2 levels in umbilical cord blood and the quality of the harvested material. Additionally the effect of pH and pCO2 on the number of cord blood CD34+ cells and their vitality was analyzed. MATERIAL AND METHODS: The study included 50 pregnant women after vaginal delivery at term or elective cesarean section. Umbilical cord blood was collected immediately after birth. The probes were analyzed at the Polish Stem Cell Bank in Warsaw. RESULTS: The number of CD34+ cells ranged from 0.1-0.2 in white blood cells count over 12 thousand/ml and pH of > 7.3. If pH ranged between 7.35-7.40, the number of CD34+ was 0.3-0.4. The highest number of CD34+ cells was noted for pH of 7.30-7.35 and amounted to 0.4-0.5. Analysis of stem cell vitality showed that the highest level, over 98%, was obtained when pH was < 7.3 and > or = 7.4. The study revealed the viability of stem cells to drop to 97-98% at pH level of 7.3-7.4. Low values of CD34+ (0.01-0.09) were related to pCO2 of > 40.0 mmHg. For pCO2 < 38 mmHg, the value of CD34+ cells was 0.2-0.3%, which is relatively high. However when pCO2 was > or = 38 mmHg, the number of CD34+ ranged between 0.1-0.2. CONCLUSIONS: Viability of the umbilical cord stem cells increases along with the decrease of pH and pCO2 levels. The mode of delivery does not influence the viability of the stem cells.