For men and women who yearn for children and try unsuccessfully to conceive, sometimes for years, fertility problems can be devastating. In recent decades many technologies have been developed, such as in vitro fertilization, that help people conceive a child much more successfully.
New advances are made all the time, and some recent research is bringing even more hope to people who struggle with infertility.
New Sperm Testing: The Fertility Chip
On the male side, an exciting new method is a fertility chip, developed at the University of Twente in The Netherlands. The fertility chip, created by researcher Loes Segerink, can accurately count sperm as well as measure their mobility - meaning that a home sperm-count testing device could soon be available, making it possible for men to test their sperm in privacy and a familiar environment.
The costs for health insurers can also be decreased.
A sperm analysis is typically the first step of fertility research, but until now testing sperm quality has required stringent pre-test preparations and a specialized laboratory.
Tests often have to be repeated two to five times for sufficient reliability. If men can carry out the tests in the privacy of their own home, the procedure is less intimidating and awkward, and scientists believe that the probability of a reliable diagnosis would also be increased.
While there are some simple home sperm tests available on the market currently, they are limited because they simply indicate whether a man's sperm count is above or below the norm; they do not actually measure the concentration of spermatozoa.
The chip developed by Segerink can accurately count spermatozoa per milliliter of ejaculate, by flowing the spermatozoa through a fluid channel above which electrodes are fitted. When the cells flow under this electronic "bridge," their electrical resistance is changed momentarily which allows them to be counted.
The method can also distinguish between spermatozoa and other cells or particles in the fluid, for a highly accurate count.
Concentration is not the only indicator of sperm quality, however. How active the sperm are also plays a major role - this spontaneous activity is called motility. Segerink and her team suggest further research to determine whether motility, as well as shape, can also be accurately measured with the fertility chip.
Segerink believes that a small adjustment to the chip is all that is needed to sort motile sperm from non-motile sperm, to offer a truly complete test.
In 2011, Segerink received a Valorisation Grant, as a first step towards establishing a company. This will provide her with a platform for refining the fertility chip and its accompanying read-out device into a market-ready product.
"The 'fertility chip' is an interesting concept that bears further investigation," says Scott Roseff, MD, Director of the Palm Beach Center for Reproductive Medicine in Florida. "Sperm count and motility are two of the aspects we evaluate when we perform a semen analysis."
In order to conceive naturally, sperm have to swim through the vagina, cervix, uterus, and fallopian tube to reach the egg. Dr. Roseff explains that is a very long way, at the microscopic level. "The chip sorts motile from non-motile sperm, but it doesn't say if it measures rapid, straight-forward, progressive motility. Indeed, if a sperm swims in circles, it is motile but may not make its way up into the fallopian tube to reach and fertilize an egg."
Dr. Roseff agrees that sperm shape, or morphology, is important for proper fertilization to occur. "While we analyze morphology during laboratory semen testing, the chip does not look at this important parameter. If a man has a very high percentage of abnormally-shaped sperm, pregnancy may not occur."
Advances for Aging Eggs
On the female side, a common factor in fertility problems is that of aging eggs. As women wait longer to have children, they face the biological clock.
"People may scan the mirror anxiously for the first gray hair or wrinkle, but the cruelest sign of aging for half the human race is visible only on the calendar," says Coleen Murphy, PhD of Princeton University. "When women pass the age of 35, their chances of infertility, miscarriage, and birth defects rise precipitously, driven by the aging and resulting quality decline of their eggs (oocytes)."
With our longer life spans today, reproductive cessation for women now occurs before the midpoint of the average life; and it stands in sharp contrast to the rest of the body's cells, which age much slower. Murphy wanted to find the answer to the question of why that occurs.
Murphy led a study at Princeton to study reproductive and somatic aging at the molecular level. She found that the molecular mechanisms found in reproductive aging, compared to somatic (non-reproductive cell) aging, are completely different. After studying the model organism Caenorhabditis elegans, the worm-like nematode that sparked longevity research in the 1990s with the discovery of gene mutations that caused the worms to live longer, researchers used microarray technology to see which genes were being switched on and off as oocytes aged. Murphy concluded that there was little overlap between the genes required to keep oocytes healthy and the ones that generally extend life span.
These different genetic pathways help explain why a woman's fertility begins to decline after 35 years of age, while her other cells don't show significant aging until decades later. “It seems that maintaining protein and cell quality is the most important component of somatic longevity in worms,” Murphy said, “while chromosomal/DNA integrity and cell cycle control are the most critical factors for oocyte health.”
Despite the fact that the study was done on a lowly worm, the findings may be highly relevant to women. Finding ways to keep oocytes healthy longer would help with fertility for older women, and reduce the risk of age-related birth defects.
"Dr. Murphy's research at Princeton is a nice step forward in our understanding of the mechanisms underlying these differences," says Dr. Roseff. "We've always known that oocyte aging appears to take a different path than other body cell aging. While her research into reproductive aging in worms is important, we will need to see if and how this may translate into oocyte aging in humans."
