Eilish T. Donnelly

In vitro fertilization and pregnancy rates: the influence of sperm motility and morphology on IVF outcome

OBJECTIVE To determine the relationship between sperm motility and sperm morphology parameters and IVF and pregnancy rates. DESIGN Pre- and postpreparation analysis of semen samples from infertile couples undergoing IVF-ET. SETTING Andrology Laboratory, Royal Maternity Hospital, Belfast, Northern Ireland. PATIENT(S) One hundred fifty couples undergoing IVF-ET treatment at the Regional Fertility Centre. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) The ability of human sperm to achieve IVF and pregnancy was investigated in relation to motility parameters (assessed with computer-aided sperm analysis [Integrated Visual Optical System] and percent normal morphology (determined with the strict criteria). RESULT(S) Significant differences were observed in motility parameters and percent normal morphology in samples that achieved > or =50% fertilization compared with < or =50% fertilization and between samples that achieved a pregnancy compared with those that did not. Significant positive correlations were observed between percent progressive motility, the velocity of sperm movement, and morphology parameters and both IVF and pregnancy. CONCLUSION(S) Both sperm motility parameters and percent normal morphology are significant factors in predicting fertilization and pregnancy rates in IVF.

Cryopreservation of human semen and prepared sperm: effects on motility parameters and DNA integrity

OBJECTIVE To investigate effects of cryopreservation on sperm motility and DNA integrity. DESIGN Pre-cryopreservation and post-cryopreservation analysis of motility and DNA integrity of semen and prepared sperm samples. SETTING A hospital andrology laboratory. PATIENT(S) Forty men attending the Regional Fertility Centre, Belfast, Northern Ireland. INTERVENTION(S) Each sample was divided, and an aliquot was frozen unprepared. Remaining aliquots were prepared by Percoll density centrifugation (95.0:47.5) or direct swim-up procedure and divided into aliquots to allow direct comparison of fresh and frozen semen and prepared sperm (frozen with or without the addition of seminal plasma) from the same ejaculate. Samples were frozen by static-phase vapor cooling and being plunged into liquid nitrogen. Thawing was carried out at room temperature. MAIN OUTCOME MEASURE(S) Sperm DNA integrity was determined using a modified alkaline single cell gel electrophoresis (comet) assay, and motility was determined using computer-assisted semen analysis. RESULT(S) Sperm frozen unprepared in seminal fluid appeared more resistant to freezing damage than frozen prepared sperm. Further improvements can be achieved by selecting out the subpopulation of sperm with best motility and DNA integrity and freezing these sperm in seminal plasma, making this the optimal procedure. CONCLUSION(S) Freezing sperm in seminal plasma improves postthaw motility and DNA integrity.

Antioxidant supplementation in vitro does not improve human sperm motility

OBJECTIVE To determine the effects of supplementation of preparation media with ascorbate and alpha-tocopherol on subsequent sperm motility and reactive oxygen species production. DESIGN Prospective study to analyze postpreparation human sperm motility parameters and reactive oxygen species production following antioxidant supplementation. SETTING Andrology Laboratory, Royal Maternity Hospital, Belfast, Northern Ireland. PATIENT(S) Sixty patients attending the Andrology Laboratory for semen analysis. INTERVENTION(S) Normozoospermic and asthenozoospermic semen samples (n = 10 for each control and antioxidant group) were prepared by Percoll density centrifugation (95%-47.5%) in media supplemented with ascorbate or alpha-tocopherol to different concentrations within physiologic levels. Controls were included that were not exposed to antioxidant. MAIN OUTCOME MEASURE(S) Sperm motility parameters were assessed using computer-assisted semen analysis. The generation of reactive oxygen species was determined using luminol-dependent chemiluminescence. RESULT(S) The production of reactive oxygen species by sperm was reduced by supplementation in vitro with ascorbate and alpha-tocopherol. However, progressive motility, average path velocity, curvilinear velocity, straight-line velocity, and linearity were decreased significantly, with the greatest inhibition observed with the highest concentrations of antioxidants. CONCLUSION(S) Supplementation of preparation media with ascorbate and alpha-tocopherol, either singly or in combination, is not beneficial to sperm motility.

The dextran sulphate sodium (DSS) model of colitis: an overview

The dextran sulphate sodium model of colitis has demonstrated several correlations with human inflammatory bowel disease and is deemed suitable for investigating pathogenesis, therapeutic options and the dysplasia–adenocarcinoma sequence of inflammatory bowel disease. It is widely applicable to mice, rats, hamsters and guinea pigs. This review explores the features of this model and identifies areas for further research studies.

Effects of cryopreservation on testicular sperm nuclear DNA fragmentation and its relationship with assisted conception outcome following ICSI with testicular spermatozoa

The objective of the study was to investigate the effects of freeze-thawing on testicular sperm DNA fragmentation, fertilization rates and pregnancy rates following intracytoplasmic sperm injection with testicular spermatozoa (TESE). This ongoing prospective study included 88 couples attending for infertility treatment where the man presented with obstructive azoospermia at the Regional Fertility Centre, Belfast, UK. Patients were allocated to receive TESE treatment with fresh or freeze-thawed spermatozoa. Sperm aliquots were stored in liquid nitrogen at -196 degrees C following static phase vapour cooling or cooling at controlled rates using a programmable freezer. Samples were thawed at either room temperature or 37 degrees C. Sperm nuclear DNA; assessed by the alkaline Comet assay, was significantly damaged by slow freezing followed by fast thawing. Pregnancies were more likely to be achieved with spermatozoa displaying markedly less DNA damage. However, no differences were observed in the fertilization rates, the number of blastomeres or the cumulative embryo score between TESE cycles using either fresh or frozen thawed testicular spermatozoa. The pregnancy rates tended to be higher following fresh TESE cycles (30%) compared with TESE cycles using frozen-thawed testicular spermatozoa (26%), although this difference did not reach statistical significance. It is concluded that cryopreservation of testicular spermatozoa may reduce pregnancy rates, although this will only be confirmed by a much larger multi-centre trial.

Human sperm morphology and in vitro fertilization: sperm tail defects are prognostic for fertilization failure

Summary. The aim of this study was to determine the relationship between sperm morphology and fertilization rates in vitro. Semen samples were obtained from 50 couples undergoing IVF treatment. Sperm morphology was classified by strict criteria (Tygerberg) according to head, midpiece and tail defects in neat semen and after sperm selection by Percoll gradient centrifugation. Percoll preparation significantly increased the percentage of sperm with normal morphology from 13 to 20%. However, the greatest single regression coefficient was observed with the percentage of sperm with tail defects and correlated negatively with fertilization rates in vitro both before and after Percoll preparation. Therefore, tail morphology may be of value as a prognostic factor in assisted conception both before and after Percoll preparation.—

Metallothionein crypt-restricted immunopositivity indices (MTCRII) correlate with aberrant crypt foci (ACF) in mouse colon

Metallothionein (MT) crypt-restricted immunopositivity indices (MTCRII) are colonic crypt stem cell mutation markers that may be induced early and in abundance after mutagen treatment. Metallothionein is the endogenous reporter gene for MTCRII, but is not typically implicated in the classical pathway of colorectal tumorigenesis. Hence, the oncological relevance of MTCRII is unclear. This study tests the hypothesis that MTCRII induced by N-methyl-N-nitrosourea (MNU) and lambda carrageenan (λCgN) associate with aberrant crypt foci (ACF) in mouse colon. Undegraded λCgN and MNU were tested alone and in combination against MTCRII and ACF in Balb/c mice, at 20 weeks after the start of treatment. MTCRII were unaffected by λCgN alone. Combined λCgN/MNU treatments induced greater MTCRII (P<0.01) as well as greater number (P<0.001) and crypt multiplicity (P<0.01) of ACF than MNU alone. MTCRII were approximately 10-fold more numerous than ACF, although linear correlations were observed between these parameters (r=0.732; P<0.01). MTCRII are induced by λCgN/MNU interactions in sufficient numbers to provide statistical power from relatively small sample sizes and correlate with ACF formation. MTCRII could thus provide the basis for a novel medium-term murine bioassay relevant to early-stage colorectal tumorigenesis.