Association of Vitamin D Status with Semen Parameters and Male Reproductive Hormones in Egyptian Infertile Men

Research Article

Austin Andrology. 2021; 5(1): 1028.

Association of Vitamin D Status with Semen Parameters and Male Reproductive Hormones in Egyptian Infertile Men

Doaa Abou-Taleb AE¹*, Mahran AM¹1, Mahmoud MA² and Gaber MA³

1Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Assiut University, Assiut, Arab Republic of Egypt

2Luxor International Hospital, Luxor, Arab Republic of Egypt

3Department of Medical Biochemistry, Assiut University, Assiut, Arab Republic of Egypt

*Corresponding author: Doaa AE Abou-Taleb, Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Assiut University, Assiut, Egypt

Received: August 01, 2021; Accepted: August 20, 2021; Published: August 27, 2021

Abstract

Background: Although vitamin D receptor (VDR) is expressed in human sperm, little is known about the role of vitamin D (Vit. D) in male reproduction. Our objective was to assess Vit. D levels both in serum and seminal fluid and to establish the relation between serum and seminal Vit. D levels, semen parameters, male sex hormones and serum calcium level in Egyptian infertile men.

Patients and Methods: We conducted a prospective case control study including 30 healthy fertile males as a control group and 60 male patients with infertility of unknown etiology. Semen samples were collected and semen parameters were evaluated. Also, seminal Vit. D level was measured. Blood samples were taken as serum levels of Vit. D, calcium, testosterone, Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) were estimated.

Results: There was significant decrease of both serum and seminal Vit. D level in groups of male infertility compared to control group. A significant positive correlation was found between serum and seminal Vit. D levels in different study groups. Also, significant positive correlation between serum Vit. D level and non-progressive sperm motility.

Conclusion: Our results support the role of Vit. D in semen parameters and male fertility status.

Keywords: Vitamin D; Male infertility; Semen parameters; Reproductive hormones

Background

Infertility is failure to achieve a clinical pregnancy after a year or more of unprotected and regular sexual intercourse [1], or due to an impairment of a person’s capacity to reproduce either as an individual or with his/her partner. There are 2 types of male infertility. Primary male infertility which means a male who has never initiated a clinical pregnancy and meets the criteria of being classified as infertile. While a male who is unable to initiate a clinical pregnancy, but had previously initiated a clinical pregnancy is defined as secondary male infertility [2]. About 15% of couples are suffering from infertility, among them; approximately 50% of the cases infertility is partially or wholly attributable to a male factor [3,4].

Male infertility can be due to identifiable hormonal or anatomical causes that may be reversible or irreversible [5] Hormonal etiologies of male infertility are often referred as pre-testicular causes. Fertility impairment in these cases is due to either hormonal deficiency or excess [6]. Normal functioning of the hypothalamus, pituitary glands and testes is required for male fertility and complete male germ cell maturation is dependent on the balanced hormonal secretion of these glands [7].

Hypogonadotrophic hypogonadism which is the failure of pituitary gland to secrete adequate amounts of FSH and LH can lead to decreased sperm count and male infertility [8]. In addition; in oligospermic males hyperprolactinemia can cause infertility. It inhibits the pulsatile secretion of the gonadotrophin releasing hormone with subsequent decreased pulsatile release of FSH, LH and testosterone, which in turn causes spermatogenic arrest and impaired sperm motility. It leads to secondary hypogonadism and male infertility [9].

The exact etiology of male infertility remains unknown in 30% to 50% of patients, who are classified as having idiopathic male infertility [10], which characterized by the presence of abnormal semen parameters without a discernible cause and absence of female infertility [11]. In contrast, unexplained male infertility is the inability of the male to establish pregnancy, despite having normal semen parameters without any known cause of infertility and the absence of female factor of infertility [12].

Although vitamin D (Vit. D) is most strictly connected with regulation of calcium and bone homeostasis [13], it has been suggested to have many other actions, including effects on the immune system, diabetes, and cancer prevention [14,15]. One of the recently identified target zones of Vit. D is male reproductive function. The basis of the interplay between Vit. D and reproduction lays on the expression of both Vit. D in Vit. D receptors (VDR) and all the Vit. D3 metabolic enzymes (CYP2R1, CYP27B1, and CYP24A1) in different tissues of the reproductive system in both sex [16]. VDR was shown to be expressed in neck and post-acrosomal regions of the sperm, and found to be higher in normal men than in infertile men [17]. The metabolizing enzymes are expressed in testis, epididymis, seminal vesicle, prostate, and spermatozoa suggesting a local regulation of active Vit. D that may be important for spermatogenesis and sperm function [18].

The exact role of VDR in the sperm nucleus is not known. It may act as a protective genomic factor, as it is essential for the proper control of sperm DNA integrity and maintenance of genome stability [19]. Vit. D could decrease early apoptosis and necrosis, and increase sperm motility in asthenozoospermia [20]. Hypovitaminosis D has a negative impact on semen and hormone function, either in animals or in humans [21].

It has been suggested that Vit. D increases intracellular calcium concentration and sperm motility, and induces acrosome reaction in mature sperm from healthy males [18,22]. Vit. D might also enhance sperm motility by promoting the synthesis of ATP, both through the cAMP/PKA pathway and the increase in intracellular calcium ions [23,24].

Previous researchers have found positive relationship between the serum level of Vit. D and semen parameters [18-22]. However, the relation between serum and seminal levels of Vit. D, semen parameters and male sex hormones, is still unclear.

Our objective was to assess both seminal and serum Vit. D levels in Egyptian infertile males and to verify if serum Vit. D level is a reflection of its seminal level. Also, to establish the relation between serum and seminal Vit. D levels, semen parameters, male reproductive hormones and serum calcium level in Egyptian infertile men.

Patients and Methods

Study design and population

A prospective case control study was performed at Dermatology, Venereology and Andrology Department and Medical Biochemistry Department, Faculty of Medicine, Assiut University, Assiut, Arab Republic of Egypt. The study received an approval from the Medical Ethics Committee of Faculty of Medicine, Assiut University (Approval number IRB17100087). From all participants an informed consent was obtained before the study.

All infertile male patients attending the Andrology Outpatient Clinic of Assiut University Hospital (AUH) were screened. After excluding 186 cases of infertile men not fulfilled the inclusion criteria, a total of 60 male patients with infertility of unknown etiology were incorporated in the study. In addition, 30 healthy fertile males (as controls) were randomly recruited.

Inclusion criteria included infertile male patients without any detectable cause of infertility with normal clinical examination ± normal semen parameters.

Exclusion criteria

The study excluded patients with any apparent physical finding and any known pathology of the reproductive tract (e.g. prostatitis, epididymitis, any genital tract infections, varicocele, diminished testicular volume or abnormal hormonal profile, etc.), or those received Vit. D therapy or other hormonal therapy. Moreover, patients with chronic systemic disease, cancer, malabsorption, poor general status or combined male and female factor of infertility were also excluded.

The participants were subdivided into 3 groups

• Control group: included 30 fertile males.

• Unexplained male infertility group: included 30 infertile male patients with normal clinical examination and normal semen parameters.

• Idiopathic male infertility group: included 30 infertile male patients presented with normal clinical examination and abnormal semen parameters.

A detailed history was taken from all patients including: personal, sexual, medical history and family history in addition to the fertility history of his wife. General physical examination and genital examination of testis, epididymis, vas deferens, spermatic cord, penis, scrotum and inguinal lymph nodes were performed.

Semen analysis

From all patients semen samples were collected after 2-5 days of sexual abstinence. It was obtained by masturbation into a sterile plastic container. Patients were instructed to report any semen loss during semen collection. After complete liquefaction in 37ºC incubator, semen samples were evaluated for physical criteria and then centrifuged where the pellets are used to assess the semen parameters based on World Health Organization (WHO) laboratory manual [3]. Normal sperm parameters are considered if total sperm count >39 million sperm per ejaculate, sperm concentration >15 million sperm per ml, progressive motility >32%, total motility >40% and normal morphology ≥4%. Seminal fluid was evaluated for Vit. D level as described in the kit manual supplied by Epitope Diagnostics, Inc (EDITM Total 25-OH Vit. D EIA Kit, Cat No.: KT715, United States).

Biochemical analysis

Venous blood samples from all patients were collected via venipuncture of superficial vessels in the antecubital fossa or hands by a well-trained clinician. Five ml of peripheral venous blood was withdrawn from each patient; it was dispensed into plain tubes then centrifuged for 15-minutes at the speed of 2000-3000 r.p.m. and serum collected. Serum is divided into 5 eppendorf tubes then stored in -20ºC to avoid repeated freeze-thaw cycles till batch assay of our markers. Serum level of total Vit. D was measured using the same kit as seminal levels (EDITM Total 25-OH Vit. D EIA Kit, Cat No.: KT715, United States), serum calcium was measured by colorimetric method using abcam assay kit (ab102505, United Kingdome). FSH and LH levels were measured by enzyme-linked immunosorbent assay (ELISA) kits supplied by Perfecta Ease Biotec (Beijing) co., USA, Cat No.:10001 and 10004 respectively. Testosterone Hormone levels were detected by ELISA kit supplied by Abia (AB diagnostic system, German, Cat No.: DK.004.01.3).

Statistical analysis

The data were analyzed using the Statistical Package of Social Science (SPSS version 19; SPSS Inc., Chicago, IL) software program. Data statistically stated in terms of number, percentage, mean, median, range and Standard Deviation (SD). Chi-square test was used to compare between qualitative variables. Independent samples t-test was used to compare quantitative variables between two groups in case of parametric data and Mann-Whitney test was used for non-parametric data. Spearman correlation was used to measure the correlation between quantitative variables. A P-value ≤0.05 was considered statistically significant.

Determination of the threshold value for optimal sensitivity and specificity of our markers was done by the Receiver Operating Characteristics (ROC) curve, which was plotted by calculating sensitivity and specificity at multiple cut-off points. Area Under the Curve (AUC) of the ROC plots was calculated using discriminate analysis, where AUC=1.0 means perfect separation of test values into two groups and AUC = 0.5 means no distributional differences. AUC >0.8 indicates excellent discriminating power of the test and AUC >0.7 indicates a discriminating strength of statistical significance.

Results

The Demographic data of the study

The demographic data of the studied groups were summarized in (Table 1). A total of 60 infertile male patients of unknown etiology were included in the study and were divided into 2 groups as mentioned before. There was no statistical significant difference in the mean age between the studied case groups and the control healthy group (29.93±4.39, 29.20±5.27 versus 28.70±3.71 respectively). Both types of infertility were more common in smokers, workers and rural residents.