Metabolomics: a bird's eye view of infertile men: review article

Infertility influences an estimated 20% of couples worldwide. The factors that can affect the fertility potential are equally distributed between men and women. Despite extensive research in male infertility, the etiology in majority of infertile men is unknown. In 2010, there was an opinion published in Nature asking a selection of leading researchers and policy-makers about what their future focuses will be in 2020. Metabolomics was mentioned as the leading omics technology by them. The word metabolomics has been defined almost 20 years ago. However, the clinical metabolomics history goes back to more than 1,000 years ago. The great Persian physician and philosopher Avicenna observed an individual urine changes during illness. Today, the color or smell changes are known to be caused by metabolites deregulation indicating metabolic diseases. Metabolomics approach is a systematic analysis of the unique pattern followed by a specific biochemical pathway that uses a biological material, e.g. spermatozoa or human seminal plasma. For the diagnosis of infertile men, the typical parameters of semen analysis are: sperm motility, sperm morphology, concentration and count. Human seminal plasma is a valuable biological source which was not used in the diagnosis of infertile men, unfortunately. To the best of our knowledge, there is no parameter for analysis of the human seminal plasma. Thus, the need for a novel parameter to diagnose infertile men is urgently needed. We recommend the use of seminal plasma in order to diagnose infertile men according to our previous research. Only a handful studies have used metabolomics approaches in the male infertility. In this study, we summarize the current research and our contribution to the field of male infertility and metabolomics. One of our main contributions has been to use metabolic profiling of seminal plasma from non-obstructive azoospermia to find 36 potentials biomarkers for detection of spermatogenesis. A search in the PubMed using keywords “metabolomics” and “infertility” shows only 59 publications. This demonstrates how newborn the metabolomics in its application for male infertility is. In this review article we have tried to have a comprehensive and specific approach to male infertility from a metabolomics perspective and related techniques.