Sperm cells, we’re on your tails with the help of new tech
An exciting new study from the University of Birmingham shows that scientists can learn a great deal about fertility in men by analysing the movement of the tails of sperm cells [1. Gallagher MT, Cupples G, Ooi EH, Kirkman-Brown JC, Smith DJ. Rapid sperm capture: high throughput flagellar waveform analysis. Human Reproduction. 2019].
The tale of the sperm tail
Movement is vital for sperm cells. They have the crucial job of travelling all the way up the female reproductive tract in order to fertilise an egg cell. To be able to swim successfully, sperm cells rely on their tail which is also called a flagellum.
The role of the flagellum is to navigate the sperm towards an egg cell and to propel the sperm cell forwards. It does this through a whipping and beating type of action. Previously scientists have not thoroughly investigated the exact movement of the sperm’s tail and the impact of this on fertility, but this is about to change.
The scientists are on the sperm’s tail
Professor Dave Smith and his team at the University of Birmingham analysed the movement of sperm tails from samples provided by donors. Specifically, the team measured the speed and action of the sperm tail.
The team were able to do this by using rapid high-throughput digital imaging and they combined this with mathematics and fluid dynamics. To carry out this fancy technique, they used a software tool called Flagellar Analysis and Sperm Tracking, also known as FAST, to analyse microscopy videos.
In the team’s research which was recently published in the journal Human Reproduction, they used a mathematical model which measured the miniscule forces generated by the movement of a sperm cell’s tail. It would not normally be possible to detect these tiny forces in laboratory experiments.
By using this, the team were able to analyse whether the sperm cells had the potential to reach and fertilise an egg cell. The software also analysed the amount of energy the sperm cells needed to swim effectively.
What are the current methods of analysing sperm cells?
At the moment, we have a limited number of ways to analyse the movement of sperm cells to find out information about what might be the problem in patients with fertility issues. One of the most popular methods which you have probably heard of is a sperm count, which measures the number of sperm cells present in a certain amount of semen.
Sperm morphology is also part of a normal semen analysis. This involves scientists examining the size and shape of the sperm cells, and determining whether they have any defects such as multiple tails or unusually shaped heads. Sperm morphology results are given as a percentage of sperm cells which appear normal under a microscope.
Sperm motility is also measured in a semen analysis, and this involves scientists counting the number of sperm moving under a microscope. Importantly it is not just about movement as the name suggests. It is vital that the sperm cells are ‘progressively motile’, which means that they are actually swimming forwards in a reasonably straight line. This maximises the chances of the sperm cells reaching an egg cell to fertilise it.
Scientists are also able to measure the movement of the heads of sperm cells in a method called Computer Aided Sperm Analysis, or CASA. But in the new technique studied by Smith and his team using FAST, the scientists discovered information that they would not have been able to gain by studying the sperm head alone. This included insights into how the area around the sperm cells was disturbed by the movement of the cells and the metabolic requirements of mobility for sperm cells.
The team are keen to share
Smith and his team have made the FAST software widely available and free to use for other scientists and doctors. They believe that just as technology has improved every other aspect of our lives, fertility should be no exception.
By widening access to this new technology, the team aim to encourage scientific progress and an improvement in our understanding of male fertility. Currently there are no drugs available to treat male infertility, but Smith and his team hope that this will change in the near future.
The new tech could help men with fertility issues
The FAST technique offers a new insight into the movement of sperm cells. By understanding how a sperm tail should move in order to maximise a sperm cell’s mobility, scientists will be better able to diagnose the exact problems in sperm tail movement correctly.
These issues may not have even been identified by analysing the sperm head movement, or overall sperm cell motility alone. Therefore Smith and his team hope that the FAST technique will help to better diagnose and categorise fertility problems in men. Additionally by using the FAST technique the diagnoses will be more specific than the current World Health Organisation motility categories.
If scientists can identify the exact errors occurring in the movement of sperm tails, this will lead to more investigations into why these occur and how doctors can treat them. Therefore the treatments will be more tailored to the exact motility problems which occur.
This will benefit patients as men will be assigned the treatments which have the greatest chance of working for them, in addition to the relevant lifestyle changes. This will maximise the chances of patients having a child as soon as possible, as well as reducing the use of treatments which are less likely to work.
Sperm technology might be useful in other fields too
The scientists involved in this new research are hopeful that this new technology would be relevant in other areas which involve the movement of substances. This technology could help analyse the spread of bacteria in the human body. It could also be useful when investigating the movement of other fluids within enclosed spaces in the body, such as the brain.
This research shows important progress in the field of male fertility. More studies are needed to understand how this new technology can be applied to the wider population in clinical practice. Fortunately the progress of this will be greatly helped by the wide availability of the team’s FAST software.
At the moment, it is important to lead a healthy lifestyle as much as possible to maximise your fertility and improve the sperm health parameters which doctors currently measure, such as sperm count.