Does prohibitin expression regulate sperm mitochondrial membrane potential, sperm motility, and male fertility?

Prohibitin (PHB) is a highly conserved major sperm mitochondrial membrane protein whose absence in somatic cells is associated with mitochondrial membrane depolarization and increased generation of reactive oxygen species (ROS). Our recent findings suggest that high levels of oxidants in human semen may contribute to male infertility and that sperm motility could be the earliest and most sensitive indicator of oxidative damage. Based on PHB's roles in mitochondrial sub-compartmentalization and respiratory chain assembly, we examine sperm PHB expression and mitochondrial membrane potential (MITO) in infertile men with poor sperm motility (asthenospermia, A) and/or low sperm concentrations (oligoasthenospermia, OA). Here, we demonstrate that MITO is significantly lower in sperm from A and OA subjects than in normospermic (N) subjects; the decrease is more severe for OA than for A subjects. PHB expression is also significantly lower in sperm from A and OA subjects. Significantly positive correlations are found among PHB expression, MITO, and sperm motility in normospermic, asthenospermic, and oligoasthenospermic subjects. Collectively, our observations lead to the hypothesis that PHB expression is an indicator of sperm quality in infertile men, and that it regulates sperm motility via an alteration in MITO and increased ROS levels.     

The role of sperm aneuploidy as a predictor of the success of intracytoplasmic sperm injection?

BACKGROUND: We present the first powered prospective study to assess whether sperm aneuploidy can predict the outcome of ICSI. METHODS: Our null hypothesis was that aneuploidy rates (AR) are identical in men who achieve successful (Group A) and unsuccessful (Group B) ICSI outcome. A power calculation yielded a sample number of 56 to achieve 80% power to reject our hypothesis at the 5% significance level. Samples for testing were obtained on the day of embryo transfer and tests were performed on raw pre-preparation samples. Sperm AR of chromosomes 13, 18, 21, X/Y were assessed using fluorescence in-situ hybridization (FISH) techniques (mean of 1223 sperm). RESULTS: There was no significant difference in any patient, seminal, cycle or laboratory characteristic between groups that may have affected outcome. Total AR (2.37 versus 1.18%, P = 0.01), as well as AR of chromosomes 18, X/Y and 18 + X/Y (1.48 versus 0.67%, P = 0.005) were significantly higher in Group B compared with Group A. Regression analysis confirmed these differences to be independent of other variables and showed a 2.6-fold change in odds of achieving a pregnancy for every 1% change in total AR. CONCLUSIONS: Our findings confirm a potential role for aneuploidy testing in the work-up of ICSI patients as a predictor of success, as well as in future genetic counselling. If confirmed, there may also be a place for a study of preimplantation genetic screening to improve ICSI success in men found to have high AR and ICSI failure.     

Can mitochondrial DNA mutations cause sperm dysfunction?

Very low levels of somatic mitochondrial (mt)DNA deletions have been identified in the semen of infertile men. It has been suggested that these mutations cause infertility through an effect on sperm motility, but there has been no direct evidence to show that mutant mtDNA can affect sperm function. We have carried out semen analysis on a male harbouring the A3243G mtDNA mutation and show that high levels of mutant mtDNA strongly correlate with low sperm motility.     

Anonymous or identity-registered sperm donors? A study of Dutch recipients' choices

BACKGROUND: The aim of the present study was to gain insight into parents' own donor preferences within a system offering the choice between an anonymous and identity-registered donor. A comparison was made between recipients choosing for an anonymous donor (AD choosers) and those choosing for an identifiable donor (ID choosers) with regard to their sexual orientation, demographic characteristics, disclosure issues and infertility distress. METHODS: Data from 105 couples (61% heterosexual, 39% lesbian) were registered on a standardized form during implication counselling sessions previous to treatment. RESULTS: Sixty-three per cent of the heterosexual couples and 98% of the lesbian couples had chosen an ID donor. Major differences between ID and AD choosers were identified. Among the ID choosers secrecy towards the child was no option, whereas 83% of the AD choosers did not intend to inform their child. Compared with heterosexual ID choosers, AD choosers were more distressed about their infertility and had a lower educational level. CONCLUSION: Legislation imposing ID donors appears to be acceptable for the majority of this study population. For a vulnerable group of heterosexual couples, who remained secretive about the use of a donor, adaptation to the new system is not self-evident.     

How successful is repeat testicular sperm extraction in patients with azoospermia?

BACKGROUND: Little is known about the extraction rate in repeated sperm retrieval procedures in azoospermic patients. This study aimed to assess the feasibility of repeated sperm recovery in these patients. METHODS: A total of 1066 azoospermic men had their first sperm recovery between 1 January 1995 and 31 December 2003. A total of 381 men had obstructive azoospermia (OA), 628 nonobstructive azoospermia (NOA) and 57 showed hypospermatogenesis. RESULTS: Overall, sperm could be retrieved in all procedures in the 598 cycles performed in OA men (100%). A total of 117, 57, 24, 11, 7 and 1 men underwent, respectively, two, three, four, five, six and seven sperm retrievals; all were successful. Of the 784 procedures performed on the 628 men with NOA, sperm could be retrieved in 384 procedures (49%). During the first testicular sperm extraction (TESE) procedure, sperm could be extracted in 261 men with NOA (41.6%). A total of 103 men had a second attempt, 34 had a third attempt, 11 had a fourth attempt, 6 had a fifth attempt and 2 had a sixth attempt. In these cycles, sperm could be extracted in, respectively, 77 (74.7%), 28 (82.3%), 11 (100%), 5 (83.3%) and 2 (100%) men. CONCLUSION: Repeated TESE ensures a high sperm recovery rate even in patients with NOA. In NOA patients, studies reporting on TESE may therefore overestimate the retrieval rate by reallocating successful patients. These data also show that when no spermatozoa can be obtained after thawing cryopreserved testicular sperm for ICSI in NOA patients, a repeat TESE procedure can be planned.     

Development of a novel home sperm test - what are the limitations?

Sir, I read with great interest the article by Bjorndahl et al. entitled‘Development of a novel home sperm test’ publishedin the January 2006 issue of Human Reproduction. The device is based on a lateral-flow immunoassay using an anti-CD59antibody conjugated to colloidal gold to generate a visiblered line when sperm are present. Progressively motile spermfrom liquefied semen are separated by a direct swim-up throughhyaluronic acid, and the sperm fraction from the swim-up reactswith the anti-CD59 antibody. The appearance of a clear red line,due to the     

Why are sperm cells phagocytosed by leukocytes in the female genital tract?

When mammalian sperm cells enter the female genital tract, many of them are attacked and phagocytosed by leukocytes and epithelial cells. Although this intriguing phenomenon is known for almost five decades, there is no satisfactory explanation for it. Here, on the basis of recent information on the nature of the capacitated stage of mammalian sperm cells, that is, the sperm's stage of readiness for fertilizing the egg, I put forward the hypothesis that the phagocytosed sperm cells are post-capacitated cells. These cells, which lost their fertilizing ability and became functionless, apparently recruit leukocytes and then undergo apoptosis and phagocytosis and, thereby, are removed from the female genital tract. This fast removal probably prevents severe inflammation that could have been caused by necrotic products of sperm cells that remain functionless in the tract.     

Staining effect of Hibiscus sabdariffa extract on sperm cell morphology of Sprague–Dawley rats

Abstract

There is increasing awareness among people towards natural products. Due to their non-toxic properties, low pollution, and lower side effects, natural dyes are used in many day-to-day products. Although the African continent possesses plentiful plant resources, only a small amount has been exploited so far. This study evaluated the use of Hibiscus sabdariffa as a stain to evaluate sperm morphology. Following liquefaction, 10 μl of semen was spread onto glass slides and allowed to air-dry at room temperature. The smear was fixed for 15 minutes in methanol. The sperm morphology was analyzed by staining 10 slides of the smears with eosin (control) and the ethanolic extract of Hibiscus sabdariffa dye was used to stain the sperm cells. The smears were air-dried and viewed at magnification of ×400. Phytochemical and chromatographic analyses were carried out. The sperm cells were stained in shades of reddish brown. Preliminary phytochemical screening of Hibiscus sabdariffa revealed that it contains alkaloids, saponins, flavonoids, and tannins. Hibiscus sabdariffa has potential for use as a stain for study of sperm morphology.     

Do weekend oocyte retrievals have an impact on the intracytoplasmic sperm injection cycles outcome?

Introduction

Despite the fact that ovarian stimulation is controlled, it is not always predictable. Because the day of human chorionic gonadotrophin (hCG) injection depends mainly on the patient''s ovarian response to gonadotrophins, the day of oocyte retrieval cannot be determined in advance. As a result, oocyte retrievals are often scheduled to occur on weekends, a fact that entails at least one extra working day for the staff, and could lead to physical and psychological stress, especially in embryologists. The aim of this study was to evaluate whether intracytoplasmic sperm injection (ICSI) outcomes are influenced by the day of oocyte retrieval.

Material and methods

A total of 327 ICSI cycles, whose retrievals were performed on Wednesdays and Sundays, were analysed in this retrospective study. Cycles were subdivided into two groups according to the day of oocyte retrieval: group W (n = 196), cycles in which oocyte retrieval was performed on Wednesday; and group S (n = 131), cycles in which oocyte retrieval was performed on Sunday. Groups were compared regarding fertilization, implantation, pregnancy and take-home baby rates.

Results

No significant differences were observed between groups A and B regarding fertilization rate (68.9% and 72.5%; p = 0.1589), implantation rate (21.8% and 24.3%; p = 0.5714), pregnancy rate (29.9% and 31.6%; p = 0.7129) and take-home baby rate (23.6% and 28.1%; p = 0.4351).

Conclusions

A well-trained embryologist''s group adhering to staff scheduling allows large programmes to ensure a similar outcome independent of the workload or workday on which embryologists perform the manipulation of gametes.     

Reply: Development of a novel home sperm test - What are the limitations?

Sir, We appreciate the comments from Dr Alvarez and Dr Agarwal andwelcome the opportunity to address them. Regarding point 1

1. We clearly stated in the Material and Methods the selectioncriteria for the study (see Björndahl et al., 2006). Westated that we intended that a target minimum of 25% of subjectsshould have progressively motile sperm concentrations belowthe test threshold (10 million progressively motile cells/mlsemen). The selected research donors had a variety of semencharacteristics—some were recruited specifically becausethey had poor semen quality—thus     

Glycolysis and sperm motility: does a spoonful of sugar help the flagellum go round?

It is doubtful that diffusion can deliver sufficient ATP from the mitochondria to sustain activity at the distal end of the sperm flagellum. Glycolytic enzymes bound to the fibrous sheath could provide energy along the flagellum at the point it is required. An obligatory role for glycolysis is supported by the lack of progressive motility in sperm from mice where the gene for sperm-specific glyceraldehyde-3-phosphate dehydrogenase (GAPDHs) had been 'knocked out'. Here, I review some evidence against this idea. First, pure diffusion from the mitochondrion is likely to be adequate in species with smaller sperm, and it is possible that rapid ATP delivery required in larger sperm could be achieved by an adenylate kinase shuttle. Second, experience with alpha-chlorohydrin demonstrates that sperm can remain motile with normal ATP concentrations despite inhibition of GAPDHs; adverse effects only occur if glucose is added and high levels of glycolytic intermediates accumulate. These observations undermine the GAPDHs knockout mouse as evidence for an essential role of local glycolysis. Third, sperm from many species can remain motile for long periods in sugar-free media and excepting dog sperm, evidence that gluconeogenesis is a possible explanation, is weak. In most species, it is unlikely that local glycolysis is the only way that ATP can be supplied to the distal flagellum.     

Does the presence of nuclear vacuoles in human sperm selected for ICSI affect pregnancy outcome?

BACKGROUND: To verify whether or not microinjection of sperm with a normal nuclear shape but large vacuoles affects IVF-ICSI pregnancy outcome. METHODS: A comparative study testing IVF outcome parameters of IVF-ICSI, based on morphological selection of spermatozoa with normal nuclei against those based on microinjection of sperm with a normal nuclear shape but large vacuoles. An experimental group, including 28 IVF-ICSI cycles, where only embryos obtained from microinjection of spermatozoa with a normal nuclear shape but large vacuoles were transferred, was matched with a control group, including 28 IVF-ICSI cycles, where only embryos obtained from microinjection of spermatozoa with a strictly defined morphologically normal nuclear shape and content were transferred. The main outcome was IVF-ICSI pregnancy rate. RESULTS: The experimental group exhibited a significantly lower pregnancy rate per cycle and significantly higher abortion rate per pregnancy compared to the control group (18 versus 50%, and 80 versus 7%, respectively, P=0.01). CONCLUSION: Microinjection of vacuolated sperm appears to reduce the pregnancy rate and appears to be associated with early abortion.     

Can biological or clinical parameters predict testicular sperm recovery in 47,XXY Klinefelter's syndrome patients?

BACKGROUND: Contradictory results are available regarding prediction of testicular sperm extraction in 47,XXY patients. This study, therefore, aimed at assessing the availability of testicular sperm and evaluates clinical parameters predicting successful sperm retrieval in azoospermic 47,XXY Klinefelter's syndrome patients. METHODS: Sperm recovery procedures were performed in 50 non-mosaic azoospermic Klinefelter patients. The facial hair pattern and the presence of gynaecomastia in men with successful and unsuccessful sperm recovery were compared using Fisher's exact test. The predictive value of clinical parameters such as age, testicular volume, FSH, FSH:LH ratio, testosterone and androgen sensitivity index (LH x testosterone) for successful testicular sperm retrieval was evaluated using the receiver operating characteristics (ROC) curve analysis. RESULTS: In 24 patients (48%) testicular sperm were recovered. Ninety-four per cent of the men in whom sperm was found had a normal facial hair pattern compared to 93% in whom no sperm was recovered (not significant, NS). Seventeen percent of the men with successful testicular sperm extraction had gynaecomastia compared to 31% of the men with failed testicular sperm extraction (NS). The mean testicular volume of the largest testis in patients with sperm found was 4.2 ml compared to 3.6 ml in patients with no sperm found (NS). The mean FSH and testosterone values in patients with sperm recovered were 31.2 IU/l and 3.1 ng/ml versus 40.4 IU/l (P = 0.04) and 3.2 ng/ml (NS) in patients without sperm recovered. All examined clinical and biological parameters failed to predict the outcome of the testicular sperm extraction using ROC curve analysis. CONCLUSION: As in the general population of men with non-obstructive azoospermia, there are currently no clinical parameters predicting successful sperm retrieval in the subpopulation of patients with non-mosaic Klinefelter syndrome.     

Infertility: Enhancement of outcome from intracytoplasmic sperm injection: does co-culture or assisted hatching improve implantation rates?

In two separate prospectively randomized trials, intracytoplasmicsperm injection (ICSI) cycles were studied in a controlled mannerto monitor the effects of either bovine oviductal epithelialcell co-culture (n = 119) or assisted hatching by zona drilling(n = 100). In the first study, immediately following ICSI, alleggs were placed directly either onto partial monolayers ofbovine oviductal cells or into regular culture medium. Althoughthe embryo developmental rate was apparently compromised inpart by the presence of the co-culture cells, ultimately therewere no significant differences in either the viable pregnancyrate (31.6% co-culture versus 29.0% control) or the embryonicimplantation rate (11.4% co-culture versus 13.6% control). Assistedhatching also had no significant impact on ICSI cycle outcomein terms of either the viable pregnancy rate (30.0% assistedhatching versus 32.0% control) or the embryonic implantationrate (8.5% assisted hatching versus 13.5% control). However,in female patients aged 235 years, assisted hatching appearedto convey a marginally significant benefit in terms of boththe viable pregnancy rate (35.5% assisted hatching versus 11.1%control) and the embryonic implantation rate (103% assistedhatching versus 3.1 % control). It seems that the overall improvementof ICSI cycle outcome cannot be achieved by the general applicationof either co-culture or assisted hatching. Nevertheless, itis possible that there remain specific patient groups that mightbenefit from selected use of either of these modalities.