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Year : 2019  |  Volume : 32  |  Issue : 3  |  Page : 1009-1012

Evaluation of serum kisspeptin in infertile men with severe oligospermia

1 Department of Dermatology and Andrology, Faculty of Medicine, Menoufia University, Shebin El-Kom, Menoufia Governorate, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Menoufia University, Shebin El-Kom, Menoufia Governorate, Egypt
3 Department of Dermatology and Andrology, Shebin El-Kom Teaching Hospital, Shebin El-Kom, Menoufia Governorate, Egypt

Date of Submission29-Nov-2017
Date of Acceptance09-Jan-2018
Date of Web Publication17-Oct-2019

Correspondence Address:
Mohammed M El-Meligi
Quesna, Menoufia Governorate
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mmj.mmj_769_17

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The aim of this study was to determine whether an abnormality in the serum levels of kisspeptin is associated with oligospermia and male infertility.
The study of kisspeptin has yielded a new concept on the physiology of the hypothalamic–pituitary–testicular axis and thus the sexual and reproductive functions of men.
Patients and methods
Our case–control study included 44 male participants aged 20–45 years divided into two groups: a case group composed of 22 infertile men with severe oligospermia and with normal serum levels of testosterone, luteinizing hormone, follicle-stimulating hormone, and prolactin and an age-matched control group composed of 22 fertile men. Serum kisspeptin levels were evaluated by an enzyme-linked immunosorbent assay in both groups.
The results of our study showed that the serum levels of kisspeptin in the infertile oligospermic group were significantly lower than those of the fertile group.
Deficiency of serum kisspeptin might be associated with oligospermia and fertility problems.

Keywords: hypothalamus, infertility, kisspeptin, oligospermia, testosterone

How to cite this article:
Attia AM, El Hamid Yassien HA, El-Mohsen Montaser BA, El-Meligi MM. Evaluation of serum kisspeptin in infertile men with severe oligospermia. Menoufia Med J 2019;32:1009-12

How to cite this URL:
Attia AM, El Hamid Yassien HA, El-Mohsen Montaser BA, El-Meligi MM. Evaluation of serum kisspeptin in infertile men with severe oligospermia. Menoufia Med J [serial online] 2019 [cited 2020 Feb 27];32:1009-12. Available from: http://www.mmj.eg.net/text.asp?2019/32/3/1009/268844

  Introduction Top

Infertility, which is the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse, is considered a social problem in all cultures and societies [1]. The prevalence rate ranges from 3.5 to 16.7% in more developed nations and from 6.9 to 9.3% in less developed nations, with an overall median prevalence of 9% [2]. Male infertility accounts for 40–50% of infertility and affects ∼7% of all men [3]. One of the most common findings in the semen analysis of infertile men is oligospermia, which is defined as a low sperm concentration in the ejaculate (<15 million sperms/ml) representing about 34.14% of infertile men [4]. Oligospermia is classified according to sperm concentration into three grades: mild (concentrations l0–15 million sperm/ml), moderate (concentrations 5–10 million sperm/ml), and severe (concentrations <5 million sperm/ml) [5]. The hormonal treatment of male infertility involves the manipulation of the hypothalamic–pituitary–testicular axis. Kisspeptins are the peptide products of the “Kiss I” gene and “Kiss1r” gene their actions by binding to their specific receptors have yielded a new significant concept on control of the hypothalamic–pituitary–gonadal axis, and thus various reproductive and sexual functions of men [6]. The Kiss1 gene was discovered in 1996 as a tumor-suppressor gene known as metastin. The initial protein product of the Kiss1 gene is a 145-amino-acid peptide. It is cleaved into shorter, biologically active peptides known as kisspeptin-54, kisspeptin-14, kisspeptin-13, and kisspeptin-10, where each number corresponds to the number of amino acids [7]. About 3 years later, the kisspeptin receptor, which is a product of the Kiss1r gene, was discovered. The kisspeptin receptor is a member of the rhodopsin family of G-protein-coupled receptor 54. In the brain, neurons that express kisspeptin are present mainly in the hypothalamus, particularly within the infundibular nucleus and to a lesser extent in the rostral preoptic area in close apposition to gonadotropin-releasing hormone (GnRH) neurons that express kisspeptin receptors [8]. By the action of kisspeptins on their receptors, a pulsatile release of GnRH from the hypothalamus is stimulated, which in turn stimulates the release of gonadotrophic hormones from the anterior pituitary [9]. This is a complex process that requires sharing of other neuropeptides such as neurokinin B and dynorphin A [10]. Therefore, any dysfunctional or deletional mutations in the genes encoding for kisspeptins or their receptors (G-protein-coupled receptor 54) can be complicated by hypogonadotrophic hypogonadism proved by multiple researches focused mainly on mice [11]. In addition to their significant expression in the hypothalamus, Kiss1 and Kiss1r mRNAs are expressed in various peripheral tissues including the testis, where their role in spermatogenesis is highly suggested [12]. There are few data on correlations between the serum levels of kisspeptins and male infertility, for the aim of our study was to obtain these data.

  Patients and Methods Top

We designed a case–control study that included 44 male participants aged 20–45 years. The participants were divided into two groups: a patient group composed of 22 infertile men with severe oligospermia and a control group composed of 22 age-matched fertile men. A written consent form approved by the Committee of Human Rights in Research at Menoufia University was obtained from every participant in both groups before the study initiation. The study was carried out between August 2016 and June 2017. All participants in the patient group were subjected to a full assessment of history, a proper general and genital examination, and laboratory investigations in the form of semen analysis of at least two semen samples obtained by masturbation after a period of sexual abstinence of 3 days; the results were evaluated according to the criteria recommended by WHO in 2010. Finally, evaluation of serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, and testosterone was performed by analysis of nonfasting venous blood samples collected from the participants using disposable sterile syringes from which serum was separated through centrifugation at 1600g and stored at − 80°C for subsequent hormonal analysis. FSH, LH, testosterone, and prolactin were determined quantitatively using chemiluminescence immunoassay kits. Patients with a risk factor for oligospermia were excluded from the study, including any occupational exposure to excess heat or irradiation, smokers or opiate and steroid abusers. Patients with chronic systemic diseases as hepatic, uremic or diabetic patients and patients running on certain drugs as chemotherapeutic agents or drugs that can be complicated by hyperprolactinemia were also excluded from the study. In addition, exclusion criteria included obese patients, patients with varicoceles, pyospermic patients, patients with hypergonadotropic or hypogonadotrophic hypogonadism, and hyperprolactinemic patients.

Quantitative evaluation of serum kisspeptin by enzyme-linked immunosorbent assay was performed in all participants. The essential reagents required for an imunoenzymometric assay include high-affinity and high-specificity antibodies (enzyme conjugated and immobilized) with different and distinct epitope recognition in excess and native antigen. In this procedure, immobilization occurs during the assay on the surface of a microplate well through the interaction of streptavidin (serum avidin) coated on the well and exogenously added biotinylated monoclonal antikisspeptin antibody (product code: EK-048-56, human kisspeptin; Phoenix Pharmaceuticals Inc., Burlingame, California, USA). An interaction was achieved between a labeled antibody and a serum containing the native antigen in the form of a globule sandwich complex. The minimum detectable concentration was 0.15 ng/ml.

Data were fed into a computer and analyzed using the IBM SPSS software package, version 20.0 (IBM Corp., Armonk, New York, USA). Qualitative data were described using number and percentage. The Kolmogorov–Smirnov test was used to verify the normality of distribution. Quantitative data were described using range (minimum and maximum), mean, SD, and median. Significance of the obtained results was judged at the 5% level.

  Results Top

The mean age (years) and kisspeptin levels (ng/ml) of participants in both groups are listed in [Table 1]. There were no significant differences between the age of both groups [Figure 1] (the mean age of the patient group was 30.36 ± 4.19 years and the mean age of the control group was 32.68 ± 5.88 years, P = 0.140) and serum kisspeptin levels in the infertile severe oligospermic men were significantly lower than those of the fertile men (the mean serum kisspeptin of the patient group level was 21.10 ± 10.45 and the mean serum kisspeptin level in the control group was 38.50 ± 5.25, P < 0.001).
Table 1: Statistical comparison between the two groups studied according to age (years) and kisspeptin levels (ng/ml)

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Figure 1: Comparison between the two studied groups according to age (years).

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Comparison between the two studied groups according to kisspeptin levels is presented in [Figure 2].
Figure 2: Comparison between the two groups studied according to kisspeptin levels (ng/ml).

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The relationship between serum kisspeptin and the other parameters of the patient group is listed in [Table 2]. There was an insignificant correlation between serum kisspeptin levels and the age of the participant (P = 0.327), sperm count (P = 0.760), serum LH (P = 0.887), serum FSH (P = 0.259), serum prolactin level (P = 0.586), and serum testosterone level (P = 0.743).
Table 2: Correlation between kisspeptin levels and different parameters of the participants in the case group

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  Discussion Top

Kisspeptins, the peptide products of the Kiss1 gene, represent a new concept in the physiology of the reproductive axis through stimulating the pulsatile release of GnRH from the hypothalamus by binding to their specific receptors that are present in close apposition to the GnRH neurons [13]. It was reported that mutations of the Kiss1 gene can be complicated by hypogonadotrophic hypogonadism, which was confirmed by several studies indicating that kisspeptins and their receptors are considered to be one of the cornerstones in regulating the hypothalamic–pituitary–gonadal axis and, hence, sexual differentiation of the brain, the onset of puberty, and fertility [14]. Kisspeptins are also expressed in different peripheral tissues including the testis, where kisspeptins are expressed in both the tubular and the interstitial components. In the interstitial component, kisspeptins exert a direct stimulatory effect on steroidogenesis as confirmed by studies that indicated that men with mutations in the kisspeptin receptor gene have a reduction in testosterone response to human chorionic gonadotrophin [14]. At the level of seminiferous tubules, both kisspeptins and their receptors have been detected in  Sertoli cells More Details as well as various types of germ cells including spermatocytes, spermatids, and spermatozoa in the tubular compartment of the testis across several species including humans, proving that kisspeptin–KISS1R signaling plays a direct role in spermatogenesis [15]. Indeed, studies have shown a role for kisspeptin in sperm motility and fertilization capacity. In human spermatozoa, researchers have reported the presence of kisspeptin and Kiss1r on the midpiece of the flagellum, around the neck and head part. Strikingly, application of kisspeptin increases Ca 2+ and leads to a clear alteration in sperm progressive motility. This also causes a transient hyperactivation of sperm, an action blocked by co treatment with the kisspeptin receptor antagonist [16]. Therefore, kisspeptins are important for normal male fertility not only because of their role in regulating reproductive axis but also because of their reported roles in the testis. Several studies have been carried out to confirm the role of kisspeptins in regulating the reproductive axis including studies that reported a significant increase in the serum levels of FSH, LH, and testosterone after intravenous infusion of kisspeptin-54 in human males [17]. However, there are very few studies on estimation of serum levels of kisspeptins in infertile men. We hypothesized that the serum kisspeptin concentrations might be decreased in infertile men compared with fertile men. To this end, we designed our case–control study to compare the serum levels of kisspeptin in infertile oligospermic men (patient group) and their age-matched fertile group (control group). Certain criteria were used for the infertile group to exclude other causes of oligospermia by proper assessment of history, clinical examination, and investigations. The results of our study indicated that serum kisspeptin concentrations in the infertile oligospermic group were significantly lower than those of the fertile group, supported by the results of the only study carried out with the same aim [18]. The difference between our study and that reference study was that we restricted our case group to severe oligospermic men, whereas the reference study included a larger category of infertile men as azoospermic, asthenozoospermic and all grades of oligospermic males. In terms of the correlation between serum levels of kisspeptin and the other parameters included in the case group, our study indicated that there was an insignificant correlation between serum levels of kisspeptin and age, sperm count, LH level, FSH level, prolactin level, and testosterone level of the case group, and up to our best knowledge, there has been no available study assessing such correlation. As our study indicated that serum levels of kisspeptins were much lower in infertile oligospermic men than in fertile men, deficiency of kisspeptin might be a cause of oligospermia and, hence, male infertility.

  Conclusion Top

Kisspeptin can be used as a diagnostic tool for male infertility and as a line of treatment of infertility disorders, but further researches are needed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

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Hrabovszky E, Ciofi O, Vida B, Horvath MC, Keller E, Caraty A, et al. The kisspeptin system of the human hypothalamus: sexual dimorphism and relationship with gonadotrophin releasing hormone and neurokinin B neurons. Eur J Neurosci 2010; 11:1984–1998.  Back to cited text no. 8
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Tarik AR. Kiss1 and Kiss1 receptor expression in the rhesus monkey testis: a possible local regulator of testicular function. Cent Eur J Biol 2013; 8:968–974.  Back to cited text no. 15
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  [Figure 1], [Figure 2]

  [Table 1], [Table 2]


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