Biomedical subjects

Vincent W Aoki

Publications and source records attributed to Vincent W Aoki.

11 recordsLinked to original sources

PubMed2006

Global sperm deoxyribonucleic acid methylation is unaffected in protamine-deficient infertile males.

Sperm protamine-1 (P1) and protamine-2 (P2) concentrations were evaluated concomitantly with global DNA methylation patterns in a population of male infertility patients. Protamine quantification and immunofluorescence microscopy in conjunction with quantitative image analysis revealed no significant relationships between the P1/P2 ratio, P1 concentrations, or P2 concentrations and levels of global DNA methylation in mature spermatozoa.

Adult↗

PubMed2006

Sperm protamine 1/protamine 2 ratios are related to in vitro fertilization pregnancy rates and predictive of fertilization ability.

OBJECTIVE: To evaluate whether aberrant sperm P1/P2 ratios are predictive of abnormal fertilizing ability and are related to in vitro fertilization (IVF) outcome. DESIGN: Prospective case-control study. SETTING: University-based infertility and IVF clinic. PATIENT(S): Forty-three male infertility patients with an abnormally reduced P1/P2 ratio, 251 patients with a normal P1/P2 ratio, and 121 patients with an abnormally elevated P1/P2 ratio. INTERVENTION(S): Human IVF, the sperm penetration assay (SPA), and sperm protamine quantification via nuclear protein extraction, gel electrophoresis, and densitometry analysis. MAIN OUTCOME MEASURE(S): Sperm P1/P2 ratios; P1 and P2 quantities; SPA scores; and IVF-fertilization, embryo-quality, pregnancy, delivery, and spontaneous-abortion rates. RESULT(S): Standard IVF fertilization rates and SPA scores were significantly reduced in patients with abnormally low and high P1/P2 ratios. In vitro fertilization embryo quality was comparable between these groups, but pregnancy rates were significantly reduced in patients with abnormally reduced P1/P2 ratios. CONCLUSION(S): The P1/P2 ratio has a significant relationship to sperm fertilization ability. The relationship between protamines and fertilization ability is not understood but may be either a reflection of generalized abnormalities during spermiogenesis or an indication of protamine deficiency acting as a regulator or checkpoint of spermatogenesis.

Biomarkers↗

PubMed2006

Identification of novel polymorphisms in the nuclear protein genes and their relationship with human sperm protamine deficiency and severe male infertility.

OBJECTIVE: To screen populations of fertile men, severely infertile men, and infertility patients with aberrations in the protamine-1-to-protamine-2 ratio (P1/P2) for clinically relevant alterations in the P1, P2, transition protein 1 (TP1), and transition protein 2 (TP2) genes. DESIGN: Prospective case-control study. SETTING: University-based infertility clinic. PATIENT(S): Ninety-six fertile men, 96 severely infertile men, and 96 infertility patients with aberrations in the sperm P1/P2 ratio. INTERVENTION(S): Sperm nuclear protein extraction, gel electrophoresis, and densitometry to evaluate the P1/P2 ratios of infertility patients. DNA extraction, polymerase chain reaction (PCR), and gene sequencing to screen the nuclear protein genes. MAIN OUTCOME MEASURE(S): Sperm P1/P2 ratios and single nucleotide polymorphisms (SNPs) in the sperm nuclear protein genes (P1, P2, TP1, and TP2). RESULT(S): Fifteen SNPs were identified in the nuclear protein genes, 12 of which were previously unreported. Five variants were identified that resulted in amino acid changes (one in P1, one in TP1, and three in TP2). The frequency of the 15 SNPs was similar in protamine-deficient patients, severely infertile patients, and fertile controls. CONCLUSION(S): A number of SNPs are present in the testis-specific nuclear protein genes. However, the gene variants do not appear to underlie protamine deficiency and severe male infertility.

Adult↗

PubMed2006

Protamine levels vary between individual sperm cells of infertile human males and correlate with viability and DNA integrity.

Sperm protamine deficiency has been associated with human male infertility. However, most studies have adopted a global approach to assessing sperm protamine levels. Thus, it is not known whether sperm cells from individual human males possess variations in protamine protein content. The objectives of this study were to evaluate variations in protamine-1 (P1) and protamine-2 (P2) content between individual sperm cells of fertile and infertile men and to correlate DNA integrity and sperm cell viability with protamine levels in individual sperm cells. The semen samples of fertile and infertile men were evaluated globally for protamine protein content using nuclear protein extraction, gel electrophoresis, and densitometry analysis. Individual sperm cell P1 and P2 levels were assessed using immunofluorescence microscopy in conjunction with automated image analysis. The terminal transferase dUTP nick end labeling (TUNEL) assay was performed simultaneously with protamine immunostaining to assess the relationship between protamine levels and DNA integrity in individual spermatozoa. Additionally, the relationship between sperm cell viability and protamine levels was assessed via viability staining concomitant with protamine staining. The protamine fluorescence data demonstrate significant variations in protamine content within individual sperm cells of human males. Overall population-based measures of DNA integrity and sperm cell viability correlate significantly with population-based measurements of protamine levels. The data also demonstrate individual sperm cells displaying the lowest protamine levels display diminished viability and increased sperm cell susceptibility to DNA damage.

Cell Survival↗

PubMed2005

Identification and evaluation of a novel sperm protamine abnormality in a population of infertile males.

BACKGROUND: A significant relationship exists between an abnormally high sperm protamine-1 (P1)/protamine-2 (P2) ratio and male infertility. In this study we investigate whether a decreased P1/P2 ratio is also linked to male infertility and we attempt to describe, at the protein expression level, the underlying cause of sperm P1/P2 deregulation. METHODS: P1 and P2 protein concentrations were quantified in sperm from 272 infertility patients and 87 fertile donors. P1/P2 ratios and protamine quantity were correlated with fertility status using semen analysis, sperm penetration capacity, and IVF data. RESULTS: We identified four distinct groups in the study: normal P1/P2 fertile donors, normal P1/P2 patients, low P1/P2 patients, and high P1/P2 patients. P1 and P2 were both under-expressed in patients with a normal P1/P2 ratio, but not in fertile donors. In patients with a low P1/P2 ratio, P1 was under-expressed while P2 was over-expressed; in patients with a high P1/P2 ratio, P1 was normally expressed and P2 was under-expressed. Patients with abnormal P1/P2 ratios displayed significantly reduced semen quality and sperm penetration ability. CONCLUSIONS: We have identified a novel population of infertile males with a reduced P1/P2 ratio. Aberrant P1/P2 ratios arise from an abnormal concentration of P1 and/or P2, either of which is associated with male infertility.

Female↗

PubMed2005

Correlation of sperm penetration assay score with polyspermy rate in in-vitro fertilization.

BACKGROUND: The sperm penetration assay (SPA) is used to predict the fertilizing capacity of sperm. Thus, some programs rely on SPA scores to formulate insemination plans in conjunction with in-vitro fertilization (IVF) cycles. The purpose of this study was to evaluate if a relationship exists between SPA scores and polyspermy rates during conventional IVF cycles. METHODS: A total of 1350 consecutive IVF patients using conventional IVF insemination were evaluated in the study. Oocytes were inseminated three hours post-retrieval by the addition of 150,000 to 300,000 progressively motile sperm. Approximately 18 hours after insemination, the oocytes were evaluated for fertilization by the visualization of pronuclei. The presence of three or more pronuclei was indicative of polyspermy. Polyspermy rates, fertilization success, embryo quality, and pregnancy rates were analyzed retrospectively to evaluate their relationship with SPA score, count, motility, number of progressively motile sperm inseminated, oocyte pre-insemination incubation time, patient age, and diagnosis. RESULTS: A significant positive relationship was observed between SPA score and polyspermy rate (rs = 0.10, p < 0.05). Patients with a normal SPA score had significantly higher polyspermy rates than those with abnormal SPA scores (6.3% +/- 1.5% vs. 2.0% +/- 0.7%, p < 0.05). Fertilization percentage was significantly lower in the group with severely abnormal SPA scores versus all other SPA groups (57.5% +/- 2.1% vs. 70.2% +/- 1.3%, p < 0.005). Although embryo quality was not affected, both clinical pregnancy and implantation rates improved slightly as SPA score increased. In addition, there was a decrease in the rate of spontaneous abortion as SPA score increased. CONCLUSIONS: These data indicate SPA score is positively correlated with polyspermy rates and IVF fertilization percentage. Additionally, there is a slight increase in clinical pregnancy rates, and embryo implantation rates with increased SPA. Furthermore, there is a slight decrease in spontaneous abortions rates related to increased SPA.

Journal Article↗

PubMed2005

In vitro oocyte maturation and subsequent delayed fertilization is associated with increased embryo aneuploidy.

Failed fertilization and the appearance of immature oocytes are common in IVF practice; rescue intracytoplasmic sperm injection can be used as a therapy. However, this study indicates that embryos created after in vitro maturation and delayed intracytoplasmic sperm injection contain an increase in aneuploidy (79.7%) over control embryos (60.5%). Therefore, patients should be informed of the possible risk when presented with delayed intracytoplasmic sperm injection.

Adult↗

PubMed2005

Comparison of four media types during 3-day human IVF embryo culture.

The aim of this study was to compare the effectiveness of human tubal fluid (HTF), G1.2, Sage Cleavage and Life Global media for IVF outcome during 3-day culture of human embryos. A three-phase auto-controlled study was conducted in which IVF outcome was compared between (1) HTF and G1.2, (2) HTF and Cleavage, and (3) Cleavage and Life Global. In phase 1, no differences in embryo quality were observed between HTF and G1.2. However, embryos derived from intracytoplasmic sperm injection (ICSI) displayed significantly improved quality when grown in HTF versus G1.2. No differences in pregnancy and implantation rates were observed in cases where embryos transferred were grown exclusively in HTF or G1.2 media. In phase 2, embryo quality was significantly improved for embryos cultured in Cleavage versus HTF media (P < 0.001). However, pregnancy, implantation and spontaneous abortion rates were similar between the two media. In phase 3, there were no differences in embryo quality, pregnancy, implantation, and spontaneous abortion rates between Cleavage and Life Global media. Overall, the data indicate that Life Global and Cleavage media yield similar results in a 3-day IVF culture programme. Cleavage medium is superior to HTF, as evidenced by significantly improved embryo quality (P < 0.001). Meanwhile, HTF medium is superior to G1.2 for ICSI cases.

Cleavage Stage, Ovum↗

PubMed2004

Improved in vitro fertilization embryo quality and pregnancy rates with intracytoplasmic sperm injection of sperm from fresh testicular biopsy samples vs. frozen biopsy samples.

OBJECTIVE: To compare the outcomes of first-attempt IVF-intracytoplasmic sperm injection (ICSI) cycles when using fresh testicular biopsy samples vs. frozen biopsy samples. DESIGN: Retrospective chart review of 92 consecutive first-attempt IVF-ICSI cycles. SETTING: Two IVF programs. PATIENT(S): Forty consecutive first-attempt IVF-ICSI patients using sperm from fresh testicular biopsy samples and 52 consecutive first-attempt IVF-ICSI cycles using frozen testicular biopsy samples. INTERVENTION(S): Testicular biopsy, IVF-ICSI with fresh and frozen-thawed spermatozoa. MAIN OUTCOME MEASURE(S): Fertilization rates, embryo quality, pregnancy, delivery, and spontaneous abortion rates. RESULT(S): A significantly increased ICSI fertilization percentage was obtained with frozen testicular biopsy samples (76.5% +/- 3.1%) vs. fresh biopsy samples (68.3% +/- 2.6%). However, embryo quality, pregnancy, and delivery rates were higher in the fresh biopsy group. Mean embryo score was 4.54 +/- 0.31 and 3.62 +/- 0.2 in the fresh vs. frozen group, respectively. Chemical pregnancy rates (60% vs. 49.1%), clinical pregnancy rates (56.4% vs. 41.2%), and delivery rates (48.7% vs. 31.2%) were each higher in the fresh group vs. frozen group. Accordingly, the spontaneous abortion rate was lower in the fresh group (21.7%) vs. the frozen group (33.3%). CONCLUSION(S): Although the use of frozen biopsy samples has logistical advantages, we conclude it may be advantageous to use fresh testicular biopsy samples in IVF-ICSI cases whenever possible, as fresh specimens yielded significantly improved embryo quality, generally higher pregnancy rates, and lower spontaneous abortion rates.

Abortion, Spontaneous↗

PubMed2003

Human protamines and the developing spermatid: their structure, function, expression and relationship with male infertility.

During spermiogenesis, the protamine proteins play an integral role in spermatid chromatin compaction. Recent research has focused on many facets of protamine biology, including protamine gene and protein structure/function relationships, mechanisms of protamine expression regulation and involvement of the protamines in male fertility. In this paper, we review our current understanding of the structure and function of the protamine-1 (P1) and protamine-2 (P2) proteins and genes, the expression and regulation of these genes and the relationship between the protamines and male fertility. In addition, we offer a brief outlook on future investigation into protamine proteins.

Amino Acid Sequence↗

PubMedDate not supplied

DNA integrity is compromised in protamine-deficient human sperm.

The objective of this study was to examine the relationship between DNA integrity and protamines in human sperm. One hundred forty-nine male infertility patients were included in an Institutional Review Board-approved study. Sperm were evaluated for DNA fragmentation using the DNA Integrity Assay, a test equivalent to the sperm chromatin structure assay (SCSA). Additionally, nuclear proteins were extracted and the protamine-1/protamine-2 ratio (P1/P2), protamine-1 (P1), protamine-2 (P2), and total protamine concentrations were evaluated. We identified 37 patients with abnormally low P1/P2 ratios, 99 patients with normal P1/P2 ratios, and 13 patients with abnormally high P1/P2 ratios. DNA fragmentation was significantly elevated in patients with low P1/P2 ratios (37.1 +/- 6.02) vs those with normal and high P1/P2 ratios (26.7 +/- 1.9 and 23.8 +/- 3.2, respectively; P < .05) and was inversely correlated with the P1/P2 ratio (R(s) -0.18, P < .05), P1 concentration (R(s) -0.29, P < .001), P2 concentration (R(s) - 0.24, P < .005), and total protamine concentration (R(s) -0.28, P < .001). Furthermore, chi2 analysis revealed a significant increase in the incidence of marked DNA fragmentation in patients with diminished levels of either P1 or P2. The present study is the first to report that human sperm protamine content is significantly related to DNA fragmentation. In particular, sperm P1 and P2 concentrations inversely correlate with DNA fragmentation, indicating a protective role of the protamines against sperm DNA damage. In light of recent studies highlighting the negative effect of sperm DNA damage on ART outcomes, these findings indicate a possible clinical significance for human sperm protamine levels.

DNA Fragmentation↗