Possible significance of transferrin levels in seminal plasma of fertile and infertile men

Role of Seminal Plasma Proteins in Effective Zygote Formation- A Success Road to Pregnancy

Seminal plasma proteins contributed by secretions of accessory glands plays a copious role in fertilization. Their role is overlooked for decades and even now, as Artificial Reproduction Techniques (ART) excludes the plasma components in the procedures. Recent evidences suggest the importance of these proteins starting from imparting fertility status to men, fertilization and till successful implantation of the conceptus in the female uterus. Seminal plasma is rich in diverse proteins, but a major part of the seminal plasma is constituted by very lesser number of proteins. This makes isolation and further research on non abundant protein a tough task. With the advent of much advanced proteomic techniques and bio informatics tools, studying the protein component of seminal plasma has become easy and promising. This review is focused on the role of seminal plasma proteins on various walks of fertilization process and thus, the possible exploitation of seminal plasma proteins for understanding the etiology of male related infertility issues. In addition, a compilation of seminal plasma proteins and their functions has been done.

A proteomic analysis of human follicular fluid: comparison between younger and older women with normal FSH levels

The follicular fluid (FF) is produced during folliculogenesis and contains a variety of proteins that play important roles in follicle development and oocyte maturation. Age-related infertility is usually considered as a problem that can be solved by assisted reproduction technology. Therefore, the identification of novel biomarkers that are linked to reproductive aging is the subject of this study. FF was obtained from healthy younger (20–32 years old) and older (38–42 years old) women undergoing intracytoplasmic sperm injection (ICSI) due to male factor infertility. The FF was analyzed by two-dimensional gel electrophoresis (2-DE). The power of two-dimensional gel electrophoresis and the identification of proteins were exploited using matrix-assisted laser desorption-ionization time-of-flight/time-of-flight (MALDI-TOF-TOF) mass spectrometry. Twenty three protein spots showed reproducible and significant changes in the aged compared to the young group. Of these, 19 protein spots could be identified using MALDI-TOF-TOF-MS. As a result of MASCOT search, five unique downregulated proteins were identified in the older group. These were identified as serotransferrin, hemopexin precursor, complement C3, C4 and kininogen. A number of protein markers were found that may help develop diagnostic methods of infertility.

Protein profile of the seminal plasma of collared peccaries (Pecari tajacu Linnaeus, 1758)

This study was conducted to characterize the major proteins of the peccary seminal plasma, based on the semen samples collected from nine adult and reproductively sound animals. Our approach included the use of two-dimensional electrophoresis followed by Coomassie blue staining and analysis of polypeptide maps with PDQuest Software (Bio-Rad). Proteins were identified by tandem mass spectrometry (LC-MS/MS). We detected 179 protein spots per gel and 98 spots were identified by mass spectrometry, corresponding to 23 different proteins. The combined intensity of those spots accounted for 56.2±6% of the intensities of all spots and 60.9% of the intensities of spots presented in every protein map. Protein spots identified as clusterin represented 19.7±8.3% of the integrated optical densities of all spots detected in the seminal plasma maps. There was a negative association (r=-0.87; P<0.05) between the intensity of a clusterin spot and the percentage of sperm with functional membrane. Spermadhesin porcine seminal plasma protein 1 and bodhesin 2 comprised 5.4±1.9 and 8.8±3.9% of the total intensity of all spots respectively. Many proteins appeared in a polymorphic pattern, such as clusterin (27 spots), epididymal secretory glutathione peroxidase (ten spots), inter-α-trypsin inhibitor (12 spots), and IgG-binding protein (ten spots), among others. In conclusion, we presently describe the major seminal plasma proteome of the peccary, which exhibits a distinct high expression of clusterin isoforms. Knowledge of wild species reproductive biology is crucial for an understanding of their survival strategies and adaptation in a changing environment.

Seminal plasma lactoferrin but not transferrin reflects gonadal function in dogs

Lactoferrin purified from canine seminal plasma by a three-step chromatography procedure had a molecular mass of 75.2 kDa and cross-reacted with antiserum to equine seminal plasma lactoferrin. Seminal plasma lactoferrin concentrations were determined by a competitive enzyme-linked immunosorbent assay (ELISA) by using rabbit anti-equine lactoferrin antibody and alkaline phosphatase-labeled goat anti-rabbit IgG antibody in 14 normal dogs and found to range from 12 to 197 micro g/ml, with a mean value of 77 +/- 59 micro g/ml (the mean +/- SD). Seminal plasma transferrin concentrations were determined by a sandwich ELISA with goat antibody to canine serum transferrin and alkaline phosphatase-conjugated goat anti-canine transferrin antibody and found to range from 0.32 to 12.6 micro g/m l, with a mean value of 2.44 +/- 3.25 micro g/m l. The lactoferrin concentration significantly correlated with the sperm concentration (r=0.7025, P<0.01), but there was no significant correlation between the seminal plasma transferrin concentration and sperm density. These results indicate that seminal plasma lactoferrin, but not transferrin, reflects gonadal function.

Presence of alpha1-antitrypsin and transferrin in human follicular fluid--correlation with fertilization

We purified two proteins with molecular masses of approximately 50 kDa and 80 kDa with N-terminal sequences similar to those of alpha1-antitrypsin (a1AT) and transferrin indicating that they are identical to or highly homologous to these proteins. Proteins from human follicular fluid were purified after ammonium sulfate fractionation followed by water dialysis and High Performance Liquid Chromatography. The fraction of peak 3 showed a single band on electrophoresis and its N-terminal amino acid sequence was similar to that of human serum transferrin. The fraction of peak 10 proved to be a glycoprotein and its N-terminal amino acid sequence was similar to that of human serum a1AT. There are indications that transferrin may be involved in the fertilization process. Sperm motion was assessed employing computer-assisted semen analysis. The addition of purified protein to prepared sperm samples from normospermic men significantly increases the straight-line velocity (VSL), the amplitude of lateral head displacement (ALH) and the number of progressively motile sperm. a1AT does not seem to have a stimulatory effect on sperm motility.

Seminal fibronectin-like antigen and transferrin concentrations in infertile and fertile men

Fibronectin like antigen (Fn) and transferrin (Trs) levels were measured in the seminal plasma of 40 fertile and 102 infertile men. The concentrations of both proteins were significantly (P < 0.001) higher in the fertile controls compared to the infertile groups. The levels of Fn and Trs (mean value +/- SEM) in the fertile men were 857.9 +/- 9.8 micrograms ml-1 and 164.0 +/- 6.5 micrograms ml-1, respectively; in the azoospermic men (n = 17) 552.7 +/- 24.65 micrograms ml-1 and 20.7 +/- 2.19 micrograms ml-1, respectively; in the group of severe oligozoospermia (n = 35) 568.34 +/- 25.7 micrograms ml-1 and 31.1 +/- 4.18 micrograms ml-1, respectively; in the moderate oligozoospermic group (n = 8) 572.50 +/- 47.9 micrograms ml-1 and 43.4 +/- 15.4 micrograms ml-1 respectively, and in the asthenozoospermic group (n = 26) 512.76 +/- 40.4 micrograms ml-1 and 47.0 +/- 7.9 micrograms ml-1, respectively. Of special interest was the finding from a group of 16 normospermic men (partners of couples with unexplained infertility) who showed significantly lower levels of Fn like antigen, 632.5 +/- 26.9 micrograms ml-1 (P < 0.001) and Trs 41.8 +/- 6.94 micrograms ml-1 (P < 0.0001) compared to normals. No correlation was found between Fn levels with either Trs or FSH levels or sperm count. In conclusion, our results indicate that male infertility is associated with changes in seminal plasma Fn like antigen concentrations and that it can be possibly used as an index of sperm fertilizing capacity.

Changes in seminal plasma transferrin concentration following administration of clomiphene citrate

This study was designed to investigate the functional changes in Sertoli cells following clomiphene citrate administration to patients with idiopathic infertility. The agent was administered to 44 oligozoospermic patients. Patients with improvement in sperm concentration after treatment (improvement group) showed significantly lower pretreatment follicle-stimulating hormone (FSH) levels in serum. Serum FSH and testosterone levels significantly increased in the improvement group after treatment (both p < 0.05). Seminal transferrin concentration significantly increased in the improvement group after treatment (p < 0.05), although there was no significant difference between pretreatment seminal transferrin concentration in the improvement group and that in patients with no improvement in sperm concentration. Seminal plasma transferrin concentration in patients in whom pretreatment luteinizing hormone level in serum was below 10 mIU/mL, and in those in whom the ratio of post- to pretreatment values was 1.5 or more, tended to increase after treatment. This group also contained a few more patients with improvement in sperm concentration than the other groups. The patients showing low pretreatment FSH levels and a high ratio of post- to pretreatment values demonstrated a significant increase in seminal plasma transferrin concentration after treatment (p < 0.01), and this group contained more patients with improvement than the other groups. It would appear that Sertoli cell stimulation may induce an increase in sperm concentration after clomiphene citrate administration, and the elevated transferrin secretion seems to be associated with the increase of serum FSH level after treatment.

Seminal plasma transferrin in infertile men

Seminal plasma transferrin levels were estimated in 51 men with various infertility problems and in 15 fertile subjects. The estimation of transferrin was carried out by using the radial immunodiffusion technique on LC-partigen transferrin plates. The mean value of transferrin decreased (p less than .05) in cases of azoospermia (91 +/- 51 micrograms/ejaculate). No significant difference was found in other sperm quality disorders (asthenoteratospermia = 227 +/- 141, mild OTA = 186 +/- 96, severe OTA = 247 +/- 137 micrograms/ejaculate). The mean value of transferrin decreased (p less than .05) in obstructive azoospermia cases (73 +/- 70 micrograms/ejaculate), whereas in the other causes of infertility no statistical differences were found. Transferrin was correlated with sperm count, sperm volume, and serum LH.

The concentrations of transferrin, beta 2-microglobulin, and albumin in seminal plasma in relation to sperm count

A number of studies have shown a relationship between transferrin levels in seminal plasma and sperm count. In the present study, the levels of transferrin, beta 2-microglobulin and albumin were measured in 171 samples of seminal plasma (50 subjects with normal sperm count; 32 with azoospermia; 49 with oligozoospermia; 10 with polyzoospermia; and 31 vasectomized). All three proteins were related to sperm count. It is concluded that there is a general relationship between seminal plasma proteins and sperm numbers and that some products of the sperm themselves must control the entry of plasma proteins into seminal plasma.

Seminal plasma transferrin concentration in idiopathic oligozoospermia

To investigate whether or not transferrin production is decreased in the testis of idiopathic oligozoospermia, the seminal plasma transferrin concentration was measured and the values were compared in two groups (15 men of pregnancy-proved normozoospermia and 22 patients with idiopathic oligozoospermia). Seminal plasma transferrin concentration in the pregnancy-proved normozoospermic group was 78.5 +/- 37.9 micrograms/mL, and the concentration in the patients with idiopathic oligozoospermia was 44.4 +/- 37.6 micrograms/mL. There was a significant difference between them (P less than 0.01). The patients with idiopathic oligozoospermia could be divided into two subgroups according to seminal plasma transferrin concentration and serum gonadotropin levels. One group had high transferrin levels with elevated serum gonadotropin levels. The results indicate that the determination of seminal plasma transferrin concentration is one of the useful parameters for evaluation of testicular function and also suggest that additional studies may allow for the subdivision of the patients with so-called idiopathic oligozoospermia.