SBIR-STTR Award

This proposal requests funding to develop and test a system by which cryopreserved human sperm can be thawed without damage. The P.I. points out that for most samples of cryopreserved sperm glycerol is used as the cryoprotectant. Thawing results in more than 50 percent of the sperm being damaged due to change in the osmotic environment which distends and damages or ruptures the plasma membrane. If the glycerol concentration is reduced slowly this minimizes damage but is impractical in the clinical setting. Alternative cryoprotectants which reduce damage such as ethylene glycol must be removed prior to insemination to prevent tissue irritation. A simple automated system to remove cryoprotectant from thawed human sperm at a non-damaging but rapid rate would improve success with sperm cryopreserved using glycerol. This is a phase 1 project which has three specific aims: 1) fabricate a prototype removal device to automatically and rapidly remove cryoprotectant from human sperm without a change in sperm concentration; 2) to evaluate capability of the prototype RCRD to remove cryoprotectant from sperm contained in a CryoCell container at a rate which is fast and non-damaging using glycerol as a test cryoprotectant; and 3) using thawed human sperm to compare quality of sperm deglycerolated and returned at 290 mOsm buffer using BioPore technology with that of sperm returned to that concentration buffer by conventional abrupt dilution or by slow step-wise dilution. It is suggested that fertility would be improved by use of this technology minimizing damage to human sperm. This is important for men having their sperm cryopreserved for therapy or surgery that is likely to impair testicular function. It will also benefit women requiring insemination with donor semen. It is estimated that by the year 2002 demands in these areas would be greater than 1 million and greater than 0.4 million doses respectively resulting in adequate sales potential for a system meeting project goals.

Thesaurus Terms:
biomedical automation, clinical biomedical equipment, cryopreservation, cryoprotective agent, heat injury, method development, physical separation, sperm, tissue /cell preparation cell membrane, cell osmotic pressure, cytotoxicity human tissueNational Institute of Child and Human Development (NICHD)

Cryopreserved human sperm are essential for important therapies. With standard procedures, post-thaw quality of samples from many/most patients (donors are highly selected) is unacceptable, 40 percent of the sperm are damaged, and pregnancy rate is low. Biology to improve outcome is available, but unused because of limited efforts to adapt knowledge to an approach practical in a clinical setting. This project is focused on that goal and will use containers with "gated-pore" faces and a "rapid cryoprotectant removal device" (RCRD) to eliminate post-thaw damage to human sperm resulting from rapid movement of water into the cells. Their use allows cryopreservation of sperm within a sealed container, and post-thaw opening of the gated pores and, at a rate safe for the sperm, replacement of cryo-extender with a buffer appropriate for intrauterine insemination (IUI) and not irritating to tissues--automatically and safely (for sperm and operator) without dilution or removal of sperm from the container until IUI. Phase-I demonstrated feasibility. Phase-II objectives are: (1) refine the CryoCell container and RCRD to meet standards needed for clinical trials and optimize thaw rate; (2) compare results with the new technology and standard procedures; and (3) evolve and validate procedures appropriate for clinical trials. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE

Public Health Relevance:
This Public Health Relevance is not available.

Thesaurus Terms:
Biomedical Automation, Clinical Biomedical Equipment, Cryopreservation, Cryoprotective Agent, Heat Injury, Physical Separation, Sperm, Technology /Technique Development, Tissue /Cell Preparation Cell Membrane, Cell Osmotic Pressure, Cytotoxicity Human Tissue, Male