The osmotic characteristics of human fetal liver-derived hematopoietic stem cell candidates

Hematopoietic stem cells derived from fetal liver have promising therapeutic potential for allotransplantation but require a specific protocol to minimize the damage produced by cryopreservation procedures. In this study, a fundamental approach was applied for designing a cell preservation protocol. To this end, the biophysical characteristics that describe the osmotic reaction of CD34⁺CD38^- human fetal liver stem cell candidates were studied using fluorescent microscopy. The osmotically inactive volume of the stem cell candidates was determined as 48% of the isotonic volume. The permeability coefficients for water and Me₂SO were determined at T=+22°C: L_p=0.27±0.03μmmin^-1atm ^-1, P_Me2SO=2.09±0.85×10 ^-4cmmin^-1, σ_Me2SO=0.63±0.03 and at T=+12°C: L_p=0.15±0.02μmmin^-1atm ^-1, P_Me2SO=6.44±1.42×10 ^-5cmmin^-1, σ_Me2SO=0.46±0.05. The results obtained suggest that post-hypertonic and hypotonic stress are the possible reasons for damage to a CD34⁺CD38^- cell during the cryopreservation procedure.