Current and historical perspectives on methodological flaws in processing umbilical cord blood

Area of Science:

• Stem cell biology
• Hematopoietic stem cell transplantation
• Biomaterials science

Background:

• Umbilical cord blood (UCB) hematopoietic stem cells (HSCs) are crucial for treating various diseases.
• Current UCB processing methods, including HESPAN and Miltenyi particles, yield insufficient cells for adult treatment and introduce procedural artifacts.
• Temperature variations and processing reagents can damage HSCs, affecting their properties and leading to cell loss.

Purpose of the Study:

• To identify and highlight procedural flaws in UCB processing that affect HSC yield and viability.
• To suggest improvements in UCB processing to enhance the quality and quantity of HSCs for therapeutic applications.
• To address potential toxicity risks associated with current cell separation media.

Main Methods:

• Physicochemical and electrokinetic studies were conducted on UCB mononuclear cells (MNCs).
• Investigated the effects of delayed processing, temperature extremes (ice/freezing), and cell separation media on cell properties.
• Critically assessed current methods for isolating CD34+ cells, including positive selection with antibody-linked Miltenyi particles.

Main Results:

• Procedural artifacts, including biomaterial adsorption from cell damage and reagent degradation, were identified.
• Internalization of Miltenyi particles poses a potential toxicity risk due to iron accumulation.
• Optimized processing achieved approximately 5% yield of CD34+ cells, a significant advance for adult stem cell therapy.

Conclusions:

• Avoiding ice temperatures prevents platelet activation and subsequent biomaterial adsorption, preserving UCB-MNC/HSC properties.
• Omitting positive selection with Miltenyi particles avoids harsh reagents and potential toxicity hazards.
• Improved UCB processing methods offer a promising prospect for adult stem cell therapy using a single UCB donation.