Cryopreservation of human mucosal tissues

Area of Science:

• Immunology
• Cellular Biology
• Tissue Engineering

Background:

• Leukocyte cryopreservation aids cellular immunity studies.
• Intact mucosal tissue is crucial for studying mucosal biology and STIs.
• A standardized protocol for mucosal tissue cryopreservation is lacking.

Purpose of the Study:

• To establish an optimal cryopreservation protocol for intact mucosal tissues.
• To compare cryopreservation and vitrification methods for cervicovaginal and colorectal tissues.
• To evaluate the impact of preservation methods on tissue integrity and function.

Main Methods:

• Tested slow cooling (1°C/min) with 10% dimethylsulfoxide (cryopreservation) and fast cooling with 20% dimethylsulfoxide and 20% ethylene glycol (vitrification).
• Assessed metabolic activity, HIV infectability, cell phenotype, tissue structure, cell number/viability, cytokine production, and microbicide concentrations.
• Compared fresh, cryopreserved, and vitrified human cervicovaginal and colorectal tissues.

Main Results:

• Cryopreservation and vitrification showed similar metabolic activity, HIV infectability, and tissue structure in vaginal tissues.
• Vitrification resulted in significantly lower cell recovery from colorectal mucosa (90% fewer cells).
• Cryopreserved colorectal tissues showed reduced HIV infectability compared to fresh tissues (HR 0.7).
• Cell recovery was higher from cryopreserved intact tissue pieces than from single-cell suspensions isolated before freezing.
• Cellular function remained similar to fresh tissue in both isolation methods.

Conclusions:

• Dimethylsulfoxide-based cryopreservation is effective for intact cervicovaginal and colorectal tissues.
• Vitrification has limited utility, particularly for colorectal mucosal tissues.
• Cryopreservation of intact tissue pieces yields higher cell numbers than pre-freezing single-cell isolation, with comparable T cell function.