The aim of the present study was to measure lanthanum (La), cerium (Ce), europium (Eu), and gadolinium (Gd) concentrations in human semen and correlate the results with sperm quality. The median semen content of La was 19.5 µg kg⁻¹ dry weight (dw) (range 2.27–269), of Ce was 41.9 µg kg⁻¹ dw (range 4.52 to 167), of Eu was 0.68 µg kg⁻¹ dw (range 0.06–1.95), of Gd was 3.19 µg kg⁻¹ dw (range 0.38–12.0), and of calcium (Ca) was 4063 mg kg⁻¹ dw (range 484–17,191). Concentrations of La, Ce, Eu, Gd, and Ca were significantly lower in nondrinkers’ semen than in semen from drinkers. Significant differences were detected between La, Ce, Eu, Gd, and Ca concentrations in semen from nondrinkers and moderate drinkers. Concentrations of La, Ce, and Gd in semen of short-term smokers were significantly lower than those in extremely long-term smokers. Significant differences were also detected between La concentration in semen from a group of short-term smokers and that of a group of long-term smokers. Positive correlations were found between La, Ce, Eu, Gd, and Ca concentrations in semen. La, Ce, Gd, and Ca concentrations in semen were positively associated with progressive motility and percentage of normal spermatozoa. Positive correlations were found between Ca and sperm concentration. Concentrations of La, Ce, and Gd were negatively associated with sperm concentration, whilst Ca concentration was negatively associated with volume of ejaculate. At the examined level, La, Ce, Eu, and Gd did not affect sperm quality, whereas alcohol consumption and smoking might have increased the level of rare earth elements in semen.

The inability to become pregnant for at least 1 year despite regular unprotected intercourse may indicate infertility of one or both partners. This problem affects approximately 10–20% of couples worldwide, regardless of race, with male infertility reported to account for 25–60% of cases. Among the most common pathological causes of male infertility is the presence of varicocele and chronic infections of the male reproductive system. This study was performed using data collected at the Genesis Infertility Treatment Clinic, Bydgoszcz, Poland, between 1 January 2015 and 30 June 2017. A total of 163 men meeting the inclusion criteria were selected and divided into the idiopathic infertility group (78 men) and varicocele-related infertility group (85 men). All patients received treatment with a male fertility supplement containing a combination of 1725 mg of L-carnitine fumarate, 500 mg of acetyl-L-carnitine, 90 mg of vitamin C, 20 mg of coenzyme Q10, 10 mg of zinc, 200 µg of folic acid, 50 µg of selenium, and 1.5 µg of vitamin B12 (Proxeed^® Plus, Sigma-Tau, Italy) twice a day for a period of 6 months from the time of the diagnosis of infertility. The treatment resulted in significant improvements in general semen parameters, particularly sperm count, sperm concentration, total motility, and progressive motility. This antioxidant therapy produced a particularly marked therapeutic benefit in patients with Grade III varicocele, with a greater improvement in progressive motility than in men with less severe or no varicocele. The use of the antioxidant preparation examined here seems reasonable in men with idiopathic infertility and as an adjuvant in those with varicocele-related infertility in whom surgical treatment has resulted in no improvement. Its use should be considered particularly in patients with Grade III varicocele who do not wish to undergo surgical treatment or in whom such a treatment is not possible for various reasons.