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A Heart for Service, A Mind for Science
Our many years of working in both clinical and research spheres have connected Reprovantage with numerous leaders in medicine and academia. Our professional network and board of advisors is helping to establish Reprovantage as a private research organization, with highly adaptable mobile laboratories at its core. Our desire is to advance the science of sperm cryobiology. Our mission is to continually offer to our Clients fertility preservation services which utilize the most effective protocols and technology available.
Science News
A new study, a large meta-analysis published in the journal Human Reproduction Update in Nov 2022, confirms a prior report concerning the significant decrease in sperm counts across the planet. The study presents evidence, both startling and controversial, that the average number of sperm in a semen specimen has dropped by over 50% in the last 50 years. As the claims of the report are being debated, many questions arise about the implications for the present and future of men's reproductive health.
For one, what is the cause of the apparent global decrease in male fecundity (reproductive fitness)?
Dr. Shanna Swan, the leader of the research team who conducted the study, is a world renowned reproductive epidemiologist and foremost authority on environmental factors that impact the development and function of male and female reproductive systems. Dr. Swan summarizes in her book "Count Down" decades of research findings regarding the pervasive nature of various environmental toxicants, and their insidious effects on animal and human reproduction.
"Count Down" is an important book, not only for helping to build awareness of a current public health issue, but also for providing guidance on how men and their partners can reduce their exposure to "reproductive toxicants". In this current age of lifestyle and environmental chemical assaults on reproduction, fertility should not be assumed. Men who hope to have children should take active steps to protect and preserve their fertility.
Past Studies with Future Implications
While one of the smallest of mammalian cells, the spermatozoan, or sperm cell has remarkable complexity. The sperm cell has many integrated systems, the specific actions of each must be deployed at the correct time in order for the sperm cell to fulfil its purpose; the autonomous delivery of ever-critical genetic cargo to the egg.
Reprovantage is focused on understanding how these sub-cellular systems within sperm are altered by the process of cryopreservation. Our past research in sperm structure and function provides the tools and understanding to explore potential deleterious effects associated with laboratory processing of sperm cells as well as the means to evaluate and improve methods of cryopreservation.
A variety of receptor molecules on the head of the sperm are needed to recognize and firmly bind to the outer-most layer of the egg, a "shell-like" structure called the zona pellucida (ZP). Once these receptors engage specific attachment sites on the ZP, the sperm undergoes the acrosome reaction; the surface membranes of the sperm head become fenestrated, exposing enzymes that assist sperm in the penetration of the ZP. Once through the ZP, sperm can bind to the egg membrane and fertilize the egg.
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The surface of sperm is in continual change through sperm formation and during movement in the female reproductive tract. Molecules on the sperm surface are shed while others are exposed as sperm are readied to interact with the cells and gelatinous matrix that surrounds the egg.
Using Computer Assisted Sperm Analysis (CASA), nuances in sperm motion can be tracked and studied. Sperm exhibit changes in motility, in swimming speed and directionality, in response to the different microenvironments of the female reproductive tract and to specific chemical cues released by nurse cells that encircle the egg. Changes in sperm motility are also observed with oxidative stress.
The shape of sperm, referred to as sperm morphology, is an important measure of a semen analysis. Men who produce semen specimens with many abnormally-shaped sperm generally have reduced fertility potential, even though their specimen may contain millions of sperm with a normal shape. Understanding the relationship between the normal-shaped sperm and their amorphous counterparts is an important area of ongoing research.
Sperm possess a surface-coat comprised of a dense "scaffold" of branched carbohydrates (chains of sugars). The "sugar-coat", called the glycocalyx, is deposited on sperm while they are matured and stored in the excurrent ducts of the male reproductive system (shortly after exiting the testes). Many of the sugar chains are attached to a protein backbone which inserts into the sperm surface membrane (shown above).
The ends of the sugar chains are negatively charged resulting in a "charge shell" over the entire sperm. The negative charge shell facilitates many of the activities sperm must undergo while in transport in the female reproductive tract in route to the egg (shown to the right). The surface coat is mostly released shortly before the sperm reaches the site of fertilization in the Fallopian tube, exposing important molecules on the sperm surface which allow the sperm to "recognize" and bind to the egg.
Projects in the Works
Cryos International - USA: We are working with Cryos, the world’s largest cryobank for donor sperm, on a range of projects with the ultimate goal of optimizing the processing and cryopreservation of human sperm. Reprovantage is presently developing novel sperm separation technology to quickly remove viable sperm from seminal plasma, both accelerating processing time and eliminating the damaging effects associated with centrifugation.
University of California, Davis: Dr. Catherine VandeVoort, Professor of Reproductive Biology, has studied the role oxidative stress in the impact of various lifestyle hazards (obesity, cigarette smoking, alcohol consumption, among others) on male reproduction and sperm function. She is working with Reprovantage on developing a simple assay for measuring reactive oxygen species in semen and identifying antioxidants that can be added to sperm processing media to reduce oxidative damage associated with cryopreservation.