Alzheimer's disease-related amyloid-ß1-42 peptide induces the loss of human sperm function.

Characteristically identified as the main component of senile plaques present in patients suffering from Alzheimer's disease, Aß has been detected in human testis and reproductive fluids, but its effect on spermatozoa has not been addressed. The present study evaluated whether the most toxic and aggregant amyloid precursor protein (APP)-proteolytic product, amyloid-ß1-42 (Aß1-42), was capable of affecting sperm functionality. Normozoospermic samples were either exposed to different Aß1-42 doses or to the untreated and scrambled controls for a maximum of 48 h at 37 °C and 5%CO2, and motility, viability and mitochondrial status were evaluated. Additionally, tyrosine phosphorylation was analyzed by immunocytochemistry and acrosomal integrity through PSA-FITC. A shorter treatment period was used to monitor prompt Ca2+ responses. Aß1-42 peptide decreased motility before inducing mitochondrial impairment (p < 0.05; n = 6). Both outcomes became more pronounced with time, reaching their maximal decrease at 48 h, where even 1 µM produced undesirable effects (p < 0.05; n = 6). Aß1-42 peptide also decreased cell survival (p < 0.05; n = 6). Furthermore, although no effects on tyrosine phosphorylation were observed (p > 0.05; n = 6), reduced acrosomal integrity was detected (p < 0.05; n = 7), which was not correlated with viability loss (p > 0.05). In parallel, all Aß1-42 concentrations elicited a [Ca2+]i rise but a significant difference was only observed at 20 µM (p < 0.05; n = 7) and a tendency was obtained with 10 µM (p = 0.053; n = 7). In conclusion, Aß1-42 peptide oligomers impair sperm function in vitro, although further studies are required to determine the clinical relevance of these findings.

Parental investment in couples who conceived spontaneously or with assisted reproductive techniques.

BACKGROUND: It has been suggested that couples who conceive with assisted reproductive technologies (ART) invest more in their child than those who conceive spontaneously. This study examined how parental investment in the child (PIC) varied as a function of method-of-conception, gender and other contextual variables, i.e. prenatal depression, social support and satisfaction with the marital relationship. METHODS: A total of 39 couples who conceived with ART and 34 couples who conceived spontaneously completed self-report questionnaires about depression, marital satisfaction and social support at their 24th pregnancy week and about PIC 4 months after the partum. Data were analysed with multilevel regression analyses. RESULTS: Results showed that method-of-conception and gender did not predict parental investment. There was a strong association between spouses on parental investment and investment was associated with couples' satisfaction with their marital relationship and the amount of support they perceived from their network. CONCLUSIONS: Investment in children depends on the marital relationship and support perceived from family members and friends and not on how the child was conceived nor on the gender of the parents.

Evaluation of human sperm chromatin status after selection using a modified Diff-Quik stain indicates embryo quality and pregnancy outcomes following in vitro fertilization.

Sperm chromatin/DNA damage can be measured by a variety of assays. However, it has been reported that these tests may lose prognostic value in Assisted Reproductive Technology (ART) cycles when assessed in post-prepared samples, possibly due to the normalizing effect promoted by sperm preparation procedures. We have recently implemented a modified version of the Diff-Quik staining assay that allows for the evaluation of human sperm chromatin status in native samples, together with standard sperm morphology assessment. However, the value of this parameter in terms of predicting in vitro fertilization (IVF) and Intracytoplasmic sperm injection (ICSI) outcomes after sperm selection is unknown. In this study, data from 138 couples undergoing in vitro fertilization (IVF) or Intracytoplasmic sperm injection (ICSI) treatments showed that sperm chromatin integrity was significantly improved after density gradient centrifugation and swim up (p < 0.001), but no correlations were found with fertilization or embryo development rates (p > 0.05). However, sperm samples presenting lower percentages of damaged chromatin were associated with better quality (Grade I) embryos in both ART procedures (p < 0.05) and clinical pregnancy among IVF couples (p < 0.05). Furthermore, regression analysis confirmed the clinical value of Diff-Quik staining in predicting IVF (but not ICSI) clinical pregnancy (OR: 0.927, 95% CI: 0.871-0.985, p = 0.015), and a threshold value of 34.25% for this parameter was established. The proportion of IVF couples achieving a clinical pregnancy was reduced 1.9-fold when the percentage of abnormal dark staining was ≥34.25% (p = 0.05). In conclusion, the Diff-Quik staining assay provides useful information regarding ART success, particularly in IVF cycles, where some degree of 'natural' sperm selection may occur; but not in ICSI, where sperm selection is operator dependent. This quick and low-cost assay is suggested as an alternative method to detect sperm chromatin status in minimal clinical settings, when no other well-established and robust assays (e.g. Sperm chromatin structure assay, terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling) are available.

Analysis of human spermatozoa by fluorescence in situ hybridization with preservation of the head morphology is possible by avoiding a decondensation treatment.

PURPOSE: Development of a hybridization technique for spermatozoa allowing the preservation of the head morphology. METHODS: FISH analysis of fixed semen samples from oligoasthenoteratozoospermia (OAT) patients with a normal somatic karyotype attending the Cytogenetics and the IVF Laboratories of a University hospital for semen analysis. In situ hybridization with centromeric probes for chromosomes X, Y, and 18 and locus specific probe for chromosome 21. RESULTS: More than 95% of the sperm heads showed clear hybridization signals and a conserved morphology including the visualization of the tail. Few cells with splitted signals were not considered. CONCLUSIONS: This is the first description of a simple and fast hybridization protocol for spermatozoa without a decondensation step, allowing preservation of the morphology of the sperm head that is particularly useful to correlate abnormal spermatozoa with specific chromosome aneuploidies. With this technique we were able to avoid troubles in interpretation of FISH spots that does not depend on the quality of nuclear decondensation, as it is the case in the previously described methods. Our goal was to demonstrate the efficiency of the method without loosing sperm head morphology. Further studies are needed to correlate the aneuploidy rates for specific chromosomes with sperm morphology.