Abstract

Background: In recent decades the incidence of obesity has increased, namely in industrialized countries. Unhealthy eating behaviors and lack of physical exercise have been ascribed to the major causes of obesity. Nevertheless, compelling evidence have placed new pieces in the complex puzzle of obesity's etiology. Environmental factors, known as obesogens, are functionally defined as chemicals that enhance lipid accumulation and weight gain by altering lipid metabolism or the regulation of appetite and satiety. This is a matter of great concern since obesogens can be virtually everywhere and thus, men are permanently exposed to those contaminants. Some obesogens act as endocrine disruptors altering cellular processes and physiological systems. Male infertility is one of the "silent" problems that may result from exposure to obesogens. Indeed, the observed decline in male fertility has been concurrent with the global change of the environmental exposure, supporting in part the previous hypothesis. However, the etiology of this trend in male reproductive health has posed more questions than answers. Male reproduction is extremely sensitive to environmental contaminants, since they interfere with spermatogenesis limiting the normal sperm production, compromising sperm function and/or morphology, thus impairing male fertility. Most of the studies have been focused on the clinical aspects and not on the molecular mechanisms involved in sperm formation. During sperm passage throughout, the epididymal duct undergoes a series of molecular changes mediated by proteins that are secreted by epididymal cells. This is a crucial step since these molecular transformations have huge implications in sperm functionality and may define the success of post-ejaculatory events, such as fertilization, pregnancy or even the offspring's health. It is imperative to unveil the mechanisms by which obesogens may affect sperm maturation.

Conclusion: This mini-review aims to present and discuss new insights concerning the effects of obesogens in sperm maturation. We will give special emphasis to the molecular mechanisms involved in sperm maturation and how they may be targeted by obesogens.

Keywords: Environmental contaminants, obesogens, obesity, male fertility, sperm maturation, sperm parameters.

Graphical Abstract