Impaired sperm function in infertile men relies on the membrane sterol pattern.

Membrane cholesterol removal appears a key step for the gain of fertility potential during sperm maturation. However, the membrane sterol pattern in sperm cells from infertile patients, with impaired sperm parameters, has been poorly investigated. To elucidate a causative link between sperm membrane composition in male fertility, here we have investigated the levels of cholesterol and its oxidized derivatives 7ß-hydroxycholesterol and 7-keto-cholesterol in sixteen infertile patients with oligo-asthenozoospermia and 16 normozoospermic (N) fertile subjects. Furthermore, ten of 16 N fertile subjects agreed to receive a defined testicular thermal challenge by adhering to a programme of sauna sessions for 1 month. Semen samples were obtained from each of the participants, and sperm parameters were assessed according to the World Health Organization criteria. Sperm levels of cholesterol, 7ß-hydroxycholesterol and 7-keto-cholesterol were quantified by ultra-pressure liquid chromatography mass spectrometry. The results showed that oligo-asthenozoospermia patients had a huge amount of cholesterol content compared with fertile subjects (12.40 ± 6.05 µg/106 cells vs. 0.45 ± 0.28 µg/106 cells, p < 0.001, N and oligo-asthenozoospermia, respectively). Also, oxidized derivatives were significantly higher in oligo-asthenozoospermia patients (7ß-hydroxycholesterol: 1.96 ± 1.03 ng/106 cells vs. 0.075 ± 0.05 ng/106 cells, p < 0.001 and 7-keto-cholesterol: 1.11 ± 0.72 ng/106 cells vs. 0.005 ± 0.003 ng/106 cells, p < 0.001). Moreover, sauna exposure, in parallel with a progressive worsening of sperm motility parameters, was associated with a reversible increase in sperm cholesterol after the third and fourth week of treatment, whilst 7ß-hydroxycholesterol and 7-keto-cholesterol levels showed an earlier enhancement starting from the second week. Our data show for the first time in humans a strong difference in the cholesterol and its oxidized derivatives of infertile and fertile subjects. These findings suggest a strict biochemical link relating testis function, sperm membrane status and male fertility potential.

Impact of perfluorochemicals on human health and reproduction: a male's perspective.

Perfluoroalkyl compounds (PFCs) are a class of organic molecules used in industry and consumer products. PFCs are non-biodegradable and bioaccumulate in the environment and for these reasons they have been a major subject of research regarding their toxicity, environmental fate, and sources of human exposure, since they have been shown to induce severe health consequences, such as neonatal mortality, neurotoxicity and immunotoxicity. The aim of this review is to explore the existing knowledge of the interplay between PFCs exposure and human health, with a focus on male reproductive health, given the emerging gender differences in PFCs clearance and their interaction with sex hormones receptors. A comprehensive PUBMED search was performed using relevant key terms for PFCs and male fertility. Different degrees of evidence suggest an impairment of semen parameters and sex hormones in relation to PFCs exposure. These preliminary results point towards a sex-dependent pharmacodynamics and clearance, with males having a much higher tendency to accumulation. Moreover, because of the widespread environmental occurrence of these chemicals, along with their ability to cross the placental barrier, exposure of the foetus to these compounds is inevitable. This is of concern because foetal development of the male reproductive organs may be disturbed by exposure to exogenous factors. These findings clearly suggest an antiandrogenic potential of PFCs and a link between endocrine disruptors and disorders of male health.