Oxidative stress is involved in most cases of human infertility. It is causing the aging of different organs of the human body, and the reproductive organs are no exception. It affects both sperm and eggs, and causes different types of fertilization problems, as well as abnormalities of preimplantation development of embryos, the same implantation process (nesting) of embryos in the womb, and an elevated risk of miscarriages and anomalies of the offspring.
The harmful effect of oxidative stress on sperm quality has been well known for more than 30 years and, initially, it was associated with smoking, drug use and with professional exposures to toxic substances.
The first therapies used were based on the use of antioxidant substances, both in vivo (ingestion by mouth) and in vitro (direct exposure of sperm). However, the development of intracytoplasmic micro injection of sperm into ovules (ICSI) and its subsequent extensions, including the selection of sperm to be injected using special microscopes and higher optical magnifications (IMSI), have improved the efficacy of treatments.
Healthy sperm can also be selected using their affinity (adherence) to different types of molecules attached to the plastic material. In a recent article, the research team at the MARGen clinic in Granada, led by doctors Jan Tesarik and Raquel Mendoza-Tesarik, review the history of the diagnostic and therapeutic methods used in men.
Oxidative stress in women
In the female organism, oxidative stress is currently the subject of intense study at the molecular level. In an article published by the directors of the MARGen Clinic in Granada in the International Journal of Molecular Sciences, different genes are listed whose abnormalities can cause this phenomenon. However, the effects of the malfunction of those genes appear when it is too late, with important consequences in the quantity and quality of the ovules. Often, the origin is in bad eating habits and a sedentary life. In other cases the main cause is endometriosis. Also, genetic problems cause a predisposition to premature ovarian aging.
Information on the impact of oxidative stress on the quality and quantity of eggs forms a basis for new treatments for different female pathologies. The Granada authors emphasize that “the treatment is based on the activation of antioxidant systems to eliminate the surplus reactive oxygen species. However, the choice of the most appropriate drugs, used alone or in combination, depends on a thorough evaluation of the condition of each woman. There are basically 2 types of antioxidants, indirect and direct. A well-known indirect antioxidant is growth hormone, which does not directly attack oxygen species, but rather strengthens the cells’ own systems to carry out this task. Apart from this action, growth hormone also “rejuvenates” the ovaries through other mechanisms and improves ovulation in women with polycystic ovaries. For these reasons it is recommended in women with a physiological or premature premenopause, and in cases of polycystic ovaries ”.
Among the antioxidant substances with a direct effect, vitamins C and E, folic acid, coenzyme Q10 and, above all, melatonin, the strongest of all, stand out. In addition to combining the direct and indirect antioxidant effects, melatonin also slows the development of endometriosis and adenomyosis, and acts as an immunomodulator. «This last action justifies the use of melatonin in the prevention and therapy of COVID-19, apart from strong circumstantial evidence that suggests that melatonin can act directly against the virus responsible for COVID-19, blocking its replication in infected cells, ”concludes Dr. Tesarik.
What causes it
Oxidative stress has its origin in an imbalance between the production of reactive oxygen species and the elimination of excess products from the cells. While the production of reactive oxygen species it is a necessary process to provide cells with the energy used in various intracellular processes, the excessive accumulation of these molecules can have devastating effects, causing significant damage to the mitochondria, the organelles responsible for energy metabolism. In addition, reactive oxygen species sooner or later escape from damaged mitochondria and attack other cellular components, including their genetic material (DNA).