Seminal arginase activity in infertility

Semen quality and sperm characteristics in broiler breeder cockerels fed vitamin E during hot season

Thirty-two Arbor Acres (AA) cockerels aged 27 weeks were used to determine the effect of vitamin E (VE) on the semen characteristics and sperm quality during hot season. The birds were fed diets containing 0, 50, 100 and 150mg VE kg-1 feed. There were 4 replicates and two birds per replicate. Semen collection was done thrice a week for three weeks in all birds. Dietary vitamin E significantly (p < 0.05) increased the semen volume (SV) and number of sperm cells (NS) in AA cockerels. CONTROL birds (0.71 mL) had lower SV than birds fed 150 mg VE (0.94 mL). Birds on 100 and 150 mg VE recorded similar NS, which was higher than 0 and 50 mg VE groups. The least NS was in the CONTROL group. Sperm abnormality gradually (p < 0.05) decreased as dietary VE increased from 0 to 150 mg. Significant (p < 0.01) effect of dietary VE was recorded in percentage live sperm (PLS). Semen from cockerels on VE treatment had higher PLS than the CONTROL. In conclusion, it may be beneficial to supplement the broiler breeder cockerel diet with VE up to 150 mg kg-1 feed during hot season as it increased SV, NS and PLS and decreased sperm abnormality.

Proteomics and metabolomics - Current and future perspectives in clinical andrology

Proteomics and metabolomics are emerging as promising tools to investigate the molecular mechanisms associated with male infertility. Proteins and metabolites play a pivotal role in regulating the molecular pathways associated with physiological functions of spermatozoa. Semen analysis, physical examination and laboratory work up cannot identify the etiology of infertility in 30%-40% of cases, which are classified as idiopathic. Therefore, the application of proteomics and metabolomics in the field of andrology will aid to overcome the limitations of the standard semen analysis. Understanding the molecular pathways associated with male infertility will help in planning ad hoc treatments, contributing to the clinical management of infertile patients. In this review, proteomics and metabolomics studies on spermatozoa and seminal plasma are discussed with a focus on molecular biomarkers associated with male infertility-related conditions.

Effect of sunflower lecithin on Kalahari Red goat semen during cryopreservation

Soybean lecithin had been used as an alternative to egg yolk in domestic animal semen extender during cryopreservation due to its characteristic phospholipid content which played a major cryoprotective role. This composition of soybean lecithin informed the replacement of soybean with sunflower lecithin (SL) in the extender for the Kalahari Red (KR) buck semen cryopreservation in this study. Effect of different levels of SL on the quality of the KR buck semen during cryopreservation using slow freezing method was evaluated. Semen samples were collected from four KR bucks of between two and two and half of age using artificial vagina, evaluated for motility and then diluted in extenders containing different levels of SL (1.5%, 3.0% and 4.5%) as experimental group and 0% SL or 20% egg yolk as control. Semen parameters including motility, acrosome integrity (AcI), membrane integrity (MI), malondialdehyde (MDA) concentration, cholesterol level and seminal arginase activity were evaluated for. The results showed that motility, acrosome integrity (AI) and membrane integrity were comparable at 0%, (22.00 ± 4.58, 82.00 ± 3.51 and 96.00 ± 2.03); 1.5%, (23.00 ± 2.08, 87.00 ± 3.79 and 89.00 ± 2.08); 3.0%, (13.00 ± 2.52, 81.33 ± 0.41 and 76.67 ± 1.20) and 4.5% (11.00 ± 4.51, 85.33 ± 9.88 and 84.00 ± 8.50), respectively, after thawing. SL at 0% had the highest (P < 0.05) values for MDA, cholesterol and seminal arginase activity (1.10 ± 0.008 nmol/ml, 236.35 ± 4.08 mg/dl and 0.54 ± 3.3 E-3 units/mg protein, respectively). Our data suggest that 1.5% sunflower lecithin can be used in place of soy lecithin as a substitute for egg yolk during the cryopreservation of caprine semen.

Alterations in Arginase-NO-synthase System of Spermatozoa in Human Subjects with Different Fertility Potential

BACKGROUND

Infertility is an important worldwide problem which affects 10-15% of couples globally. Altered NO production has also been implicated in the pathogenesis of the male infertility. The present study was designed to evaluate the changes in the activity of NO-synthase (NOS) and arginase in spermatozoa of patients with infertility.

METHODS

The total NOS, Ca2+-dependent constitutive (cNOS) and Ca2+-independent inducible (iNOS) activity and arginase activity were assessed in sperm cells of patients with different forms of pathospermia.

RESULTS

We found a significant increase in iNOS activity, but significantly decreased cNOS and arginase activity in sperm cells of infertile men vs fertile, normozoospermic men (p<0.001). The arginase/NOS ratio significantly decreased compared to control group. The iNOS/cNOS ratio was drastically increased in patients with decreased fertility potential indicating predominance of iNOS. Men with leuko cytospermia were distinguished to have the most express iNOS activity.

CONCLUSIONS

These observations provide evidence for a disturbed balance between the L-arginine metabolic pathways in sperm cells of infertile men. This imbalance includes the considerable activation of the inducible isoform of NO-synthase accompanied by significant inhibition of its constitutive isoform which indicates disturbances in NO production. In patients with decreased fertility potential the arginase/NOS was shifted towards predominance of iNOS-derived NO production.

Empirical Drug Therapy for Idiopathic Male Infertility: What is the New Evidence?

Idiopathic male infertility is empirically managed using a number of drugs. We reviewed 64 articles published in the last 10 years on such drug therapy. There was severe heterogeneity in data along with poor definition of outcome parameters. Pregnancy or live birth rate was not reported in many studies. Antiestrogens appear to improve pregnancy rates while there is some data supporting the use of aromatase inhibitors. Antioxidants significantly increase the rate of both live birth and pregnancy but the data are limited. However, valid end-points based on data are limited for the empirical use of drugs in idiopathic male infertility.

Major protein alterations in spermatozoa from infertile men with unilateral varicocele

BACKGROUND

The etiology of varicocele, a common cause of male factor infertility, remains unclear. Proteomic changes responsible for the underlying pathology of unilateral varicocele have not been evaluated. The objective of this prospective study was to employ proteomic techniques and bioinformatic tools to identify and analyze proteins of interest in infertile men with unilateral varicocele.

METHODS

Spermatozoa from infertile men with unilateral varicocele (n=5) and from fertile men (control; n=5) were pooled in two groups respectively. Proteins were extracted and separated by 1-D SDS-PAGE. Bands were digested and identified on a LTQ-Orbitrap Elite hybrid mass spectrometer system. Bioinformatic analysis identified the pathways and functions of the differentially expressed proteins (DEP).

RESULTS

Sperm concentration, motility and morphology were lower, and reactive oxygen species levels were higher in unilateral varicocele patients compared to healthy controls. The total number of proteins identified were 1055, 1010 and 1042 in the fertile group, and 795, 713 and 763 proteins in the unilateral varicocele group. Of the 369 DEP between both groups, 120 proteins were unique to the fertile group and 38 proteins were unique to the unilateral varicocele group. Compared to the control group, 114 proteins were overexpressed while 97 proteins were underexpressed in the unilateral varicocele group. We have identified 29 proteins of interest that are involved in spermatogenesis and other fundamental reproductive events such as sperm maturation, acquisition of sperm motility, hyperactivation, capacitation, acrosome reaction and fertilization. The major functional pathways of the 359 DEP related to the unilateral varicocele group involve metabolism, disease, immune system, gene expression, signal transduction and apoptosis. Functional annotations showed that unilateral varicocele mostly affected small molecule biochemistry and post-translational modification proteins. Proteins expressed uniquely in the unilateral varicocele group were cysteine-rich secretory protein 2 precursor (CRISP2) and arginase-2 (ARG2).

CONCLUSIONS

The expression of these proteins of interest are altered and possibly functionally compromised in infertile men with unilateral varicocele. If validated, these proteins may lead to potential biomarker(s) and help better understand the mechanism involved in the pathophysiology of unilateral varicocele in infertile men.

Distribution of arginase in tissues of cat (Felis catus)

Arginase (EC 3.5.3.1), the final enzyme in the urea cycle, catalyses the hydrolysis of l-arginine to l-ornithine and urea. High activity of this enzyme in the liver indicates its primary role in ammonia detoxification. However, its wide tissue distribution suggests that this enzyme might perform other functions besides hepatic ureagenesis. Although the distribution and properties of arginase from many tissues of human, laboratory animals and some domestic animals have been studied, little is known about the pattern of distribution and physiological roles of this enzyme in the cat. The purpose of this study was to examine and compare the distribution of arginase in different tissues of the cat. A selection of tissue samples was assayed for arginase by the diacetyl monoxime method of determination of enzymatically formed urea. The protein content of tissues and enzymatic activities were calculated as units per gram tissue and units per milligram protein of the tissue. Results showed that the liver was the richest source of arginase followed by the oesophageal and tongue mucosal layers. Significant activity of this enzyme was found in the mucosa of the small intestine, kidney cortex, lung, testis and ovary. The results of this study will be discussed in terms of the involvement of arginase in several biochemical and physiological functions in this species.

Effect of psychological stress on the L-arginine-nitric oxide pathway and semen quality

It has been reported that mental stress causes abnormality of spermiogram parameters. We investigated the effect of psychological stress on the L-arginine-nitric oxide (NO) pathway. Semen samples were collected from 29 healthy fourth semester medical students just before (stress) and 3 months after (non-stress) the final examinations. Psychological stress was measured by the State Anxiety Inventory questionnaire. After standard semen analysis, arginase activity and NO concentration were measured spectrophotometrically in the seminal plasma. Measurements were made in duplicate. During the stress period, sperm concentration (41.28 +/- 3.70 vs 77.62 +/- 7.13 x 10(6)/mL), rapid progressive motility of spermatozoa (8.79 +/- 1.66 vs 20.86 +/- 1.63%) and seminal plasma arginase activity (0.12 +/- 0.01 vs 0.22 +/- 0.01 U/mL) were significantly lower than in the non-stress situation, whereas seminal plasma NO (17.28 +/- 0.56 vs 10.02 +/- 0.49 micromol/L) was higher compared to the non-stress period (P < 0.001 for all). During stress there was a negative correlation between NO concentration and sperm concentration, the percentage of rapid progressive motility and arginase activity (r = -0.622, P < 0.01; r = -0.425, P < 0.05 and r = -0.445, P < 0.05, respectively). These results indicate that psychological stress causes an increase of NO level and a decrease of arginase activity in the L-arginine-NO pathway. Furthermore, poor sperm quality may be due to excessive production of NO under psychological stress. In the light of these results, we suggest that the arginine-NO pathway, together with arginase and NO synthase, are involved in semen quality under stress conditions.

Development of a sandwich ELISA test for arginase measurement based on monoclonal antibodies

Human arginase was purified from liver and two monoclonal antibodies (MAbs), HA1 and HA2, were produced by fusion of spleen cells from an arginase-immunized BALB/c mouse and the NS-1 myeloma cell line. Both MAbs were of the IgG3 subclass and contained the kappa light chain. HA1 inhibited arginase activity, suggesting that it binds to the arginase catalytic site. HA1 and a horseradish peroxidase-conjugated polyclonal rabbit anti-human arginase antibody were used to develop a sandwich enzyme-linked immunoadsorbent assay (ELISA) for the quantification of human arginase, which can be used in the 1 to 300 ng/mL range. Because of its sensitivity and specificity, this MAb can be successfully applied to the ELISA quantification of arginase in serum and culture supernatants.