Through the eyes of science

Our understanding of DNA has changed a lot since the molecule was described in 1953. On this journey there have been many perceptions which have later shown themselves to be wrong. Today it is a rapidly developing area of study and research into sperm DNA integrity is no exception.

The structure of DNA

The structure of DNA was described in 1953 by scientists Watson, Crick and Wilkins. In 1962, they received the Nobel Prize for their work in this field.

In the first years after the discovery it was commonly believed that DNA had to be extremely stable. This is why it came as a big surprise as it gradually became clear that DNA in body cells is actually rather fragile!

DNA is damaged millions of times per day

The majority of damage to our DNA is due to the generation of energy during cell activity. The presence of oxygen leads to oxidative stress, which continually causes damage.

The DNA in our cells is actually damaged millions of times per day! We would not be able to survive for very long if it wasn’t for the highly-developed system of DNA repair in all our body’s cells. This damage and repair are completely natural processes. It is nothing that we notice in our day-to-day lives, but our health depends on this unique balance. Cells need the ability to repair all the damage that takes place.

If cells could not overcome and repair the damage, some of the cells would die. In other cells the damage is incorrectly repaired and what some would call a mutation occurs. Mutations can affect the cell function and in some cases cause uncontrolled cell division. This is what we know as cancer.

Sperm cannot repair DNA

The sperm cell is fairly unique on a number of points. It is, for example, able to swim and has a tail. It is actually designed for transport and only contains the most essential items. One of the functions that the sperm lacks is the ability to repair DNA. To be well-protected against damage, its DNA is tightly packed.

Cancer research and sperm cells

In the field of cancer research, one of the important questions in the early 1960’s was to understand why DNA in normal cells becomes damaged. Maybe it could give an answer to the mystery of cancer.

The great challenge was to find suitable methods of examining DNA damage.

At the end of the 1970’s, scientists at the Sloan Kettering Cancer Center in New York had made significant progress on a dye called acridine-orange. It produced some interesting results. Researchers believed that it would be useful to examine a sample where the DNA was intact. For this reason they chose to examine some sperm cells.

The results of the test with sperm surprised the three scientists, Darzynkiewicz, Evenson og Melamed. Contrary to their expectations, they discovered that many sperm contained fragile DNA! They realised that this could have an influence on fertility and took out a patent on their discovery.

DNA integrity in sperm and fertility

It was not easy to show a link between sperm DNA integrity and fertility. Evenson continued to research into this field and made a number of important discoveries during the 1980’s. The method was improved and Evenson began to make use of flow cytometry, which was a relatively new technology at that time.

In the first half of the 1990’s, Evenson managed to carry out a study on natural fertility. The trial was popularly known as ”The Georgetown Study” and was the first research to show a clear connection between fertility and DNA integrity. Since 2000, several studies have been carried out to investigate the significance of the different types of fertility treatment.

Dr. Declan Keane

Dr. Declan Keane, ReproMed, Dublin, Ireland

SPZ Lab has performed the test for sperm DNA integrity for ReproMed since 2010. The SDI-test is a valuable help for us to guide the couples to the best possible fertility treatment.
Dr. Declan Keane

How to improve your DNA integrity

3 in 4 men can improve their DNA integrity and as a result increase their fertility.