Research provides new insights to help diagnose and treat unknown origin male infertility

^{Translation by Diana Taborda}

A multidisciplinary research team led by the University of Coimbra (UC) has carried out a study to increase knowledge about male infertility of unknown origin. The scientists were able to pinpoint molecular and metabolic details associated with this type of infertility, which are not routinely evaluated but could be crucial for a better diagnosis and more effective treatment.

According to Sandra Amaral, researcher of the Biology of Reproduction & Stem Cells group at the UC Centre for Neuroscience and Cell Biology (CNC-UC), infertility “is a disease with a significant impact on the life, health, and well-being of couples, who often face psychosocial and financial problems. An estimated 300,000 couples in Portugal are affected by infertility, with the male factor contributing to around 50% of cases. However, the cause of male infertility cannot be identified in around 30%of cases - the so-called male infertility of unknown origin”.

The study New Insights on Sperm Function in Male Infertility of Unknown Origin: A Multimodal Approach, published in the Biomolecules journal, involved more than 1,400 patients, analysing sperm from healthy individuals with no fertility problems, as well as men diagnosed with infertility of unknown origin. Scientists were able to identify some functional aspects of the affected male gamete: its DNA integrity (the genetic material that is passed on to future generations), the capacitation process (which gives the gamete the ability to fertilise) and also mitochondrial function (related to mitochondria, a cell organelle involved in multiple functions such as energy production).

The team also identified six proteins that are differentially expressed in individuals diagnosed with infertility. The researchers believe that all these aspects affect the ability of sperm to fertilise. "The new functional aspects that we present in this study provide new insights that may, in the future, make it possible to identify the factors that cause infertility in these men, paving the way for the development of improved diagnostic tools and future treatment options," highlights Sandra Amaral.

In men, the diagnosis of this pathology consists of an integrated evaluation that includes clinical history, a physical examination, an ultrasound scan and hormonal and semen analysis. “There is currently some concern about the routine semen analysis, due to its limitations," explains Sandra Amaral.

"Seminal analysis (which essentially consists of semen and sperm) is the cornerstone of infertility diagnosis, but it doesn't always determine the exact cause of infertility and the likelihood of conception because sperm have many other characteristics and functions that are not routinely analysed," explains the UC researcher, further adding that "This shows the need to analyse other cellular and molecular aspects of these cells, as we have done in this study, in order to gain a deeper understanding of how they work and thus better understand and treat male infertility."

The research, funded by the Portuguese Foundation for Science and Technology, involved scientists, medical doctors, embryologists, psychologists and biostatisticians, as well as three UC faculties (Faculty of Sciences and Technology, Faculty of Medicine and Faculty of Psychology and Educational Sciences), and was carried out in close collaboration with the Reproductive Medicine Service of the Coimbra Hospital and University Centre.

The first authors of the study are Rita Ivo Pacheco and Maria Inês Cristo (PhD student), and the article is available here.