A. Franchi

DNA fragmentation of normal spermatozoa negatively impacts embryo quality and intracytoplasmic sperm injection outcome.

OBJECTIVE To evaluate DNA fragmentation in morphologically normal sperm recovered from the same sample used for intracytoplasmic sperm injection (ICSI) and to correlate DNA damage with embryo quality and pregnancy outcome. DESIGN Prospective study. SETTING Academic center. PATIENT(S) 36 infertile men participating in the ICSI program. INTERVENTION(S) Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-fluorescein nick end labeling (TUNEL) assay and morphologic assessment by phase contrast. MAIN OUTCOME MEASURE(S) Simultaneous assessment of sperm morphology and DNA fragmentation by TUNEL assay was performed in the same cell, then the percentage of normal sperm with fragmented DNA (normal SFD) was correlated with embryo quality and pregnancy outcomes. RESULT(S) A highly statistically significant negative correlation was found between the percentage of normal SFD and embryo quality. This association was confirmed for the transferred embryos and for the total embryo cohort. The receiver operating characteristics curve analysis demonstrated that the percentage of normal SFD and embryo quality were statistically significant predictors of pregnancy. When the percentage of normal SFD was <or=17.6 %, the likelihood of pregnancy was 3.5 times higher. No correlation was found between the percentage of total sperm with fragmented DNA (morphologically normal and abnormal) and ICSI outcomes. CONCLUSION(S) The DNA fragmentation of morphologically normal sperm negatively impacts embryo quality and probability of pregnancy in ICSI cycles.

Fragmentation of DNA in morphologically normal human spermatozoa

OBJECTIVE To evaluate DNA fragmentation in spermatozoa with normal morphological appearance. DESIGN Prospective study. SETTING Academic tertiary center. PATIENT(S) Fertile, subfertile, and infertile men were studied. INTERVENTION(S) Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-fluorescein nick-end labeling assay and morphology assessment by phase contrast in the swim-up fractions. MAIN OUTCOME MEASURE(S) Simultaneous assessment of the percentage of normally shaped sperm and DNA fragmentation. RESULT(S) No DNA fragmentation was found in spermatozoa with normal morphology in any of the samples from the fertile group. In only one sample from the subfertile group did we observed normally shaped sperm cells exhibiting DNA fragmentation. However, in all the samples from the infertile group, we observed normal spermatozoa with DNA fragmentation. Spermatozoa from this late group exhibited a high proportion of DNA damage. CONCLUSION(S) In infertile men with moderate and severe teratozoospermia, the spermatozoa with apparently normal morphology present in the motile fractions after swim-up may have DNA fragmentation.

Pregnancy-specific β-1-glycoprotein 1 and human leukocyte antigen-E mRNA in human sperm: differential expression in fertile and infertile men and evidence of a possible functional role during early development

BACKGROUND Mature spermatozoa contain thousands of mRNA transcripts. It has been recently shown that human sperm can deliver RNA into the oocyte, suggesting that mRNAs might have a role before or after fertilization. Human embryos express PSG1 (pregnancy-specific beta-1-glycoprotein 1) and HLA-E (human leukocyte antigen-E), molecules playing a role in implantation and early development. We compared PSG1 and HLA-E sperm mRNA levels in fertile and infertile men and we tested the hypothesis that these transcripts are selectively retained in the newly formed zygote. METHODS Real-time RT-PCR was used to analyze sperm mRNA levels (n = 11 fertile, n = 31 infertile patients) of PSG1, HLA-E and PRM2 (protamine 2). The presence of PSG1 and HLA-E proteins was evaluated by western blot in sperm protein extracts (n = 3). Using ICSI of human sperm into hamster oocytes we evaluated the permanence of these mRNAs at different time points (n = 10 for each time) after fertilization. RESULTS PSG1, HLA-E and PRM2 transcripts were demonstrated in ejaculated sperm. The fertile group showed significantly higher levels of PSG1 and HLA-E mRNA (both P < 0.05) than the infertile group, whereas PRM2 levels were not significantly different. However, PSG1 and HLA-E proteins were not found in ejaculated sperm. Following ICSI, PRM2 was undetectable after fertilization; conversely, PSG1 and HLA-E transcripts remained detectable for at least 24 h of zygotic development. CONCLUSIONS We provide new evidence that indicates that human sperm deliver transcripts that may have a role in early embryo development and decreased levels of these transcripts may be associated with infertility.

Expression of immunomodulatory genes, their protein products and specific ligands/receptors during the window of implantation in the human endometrium

We have demonstrated up-regulation of the immunomodulatory genes decay accelerating factor (DAF), interleukin 15 (IL-15) and osteopontin (OPN) during the window of implantation (WOI). Here, we characterized gene expression and determined the localization of their protein products and respective ligands at the opening and closure of the WOI. In addition, we used laser capture microdissection (LCM) to analyze the cell type-specific gene expression. Human endometrial biopsies from cycle Days 16, 21 and 24 were evaluated by real-time RT-PCR. Purified epithelial and stromal cells were obtained by LCM. Localization of the proteins and their ligands was assessed by immunohistochemistry. mRNA expression of DAF, IL-15 and OPN was significantly increased throughout the WOI. DAF, OPN and alpha(v)beta(3) integrin were strongly immunolocalized to the glandular compartment by Days 21 and 24, whereas C3, IL-15 and IL-15Ralpha were highly stained in both glandular and stromal compartments. After LCM, gene expression of DAF was 4.8-fold increased in epithelium versus stroma, whereas for OPN there was a 2-fold increase. For IL-15, the expression in stroma was 8.7-fold higher than in epithelial cells. The progressive increase of the expression of these immunomodulatory genes, proteins and ligands during the WOI, support a critical role at the time of endometrial receptiveness.

Expression of milk fat globule EGF-factor 8 (MFG-E8) mRNA and protein in the human endometrium and its regulation by prolactin

Milk fat globule epidermal growth-factor 8 (MFG-E8) has not been previously linked to endometrial physiology. We reported on MFG-E8 mRNA up-regulation in the human endometrium during the window of implantation (WOI) using microarrays. Prolactin (PRL) secreted by stromal cells has been suggested to modulate protein expression. The objective of this study was to characterize the endometrial expression of MFG-E8 and its ligand αvβ3 integrin during the menstrual cycle and its possible regulation by PRL. MFG-E8 mRNA (real-time RT-PCR) and protein expression (immunohistochemistry and immunoblotting) were analyzed in human endometrial biopsies at different times of the menstrual cycle, as well as in primary endometrial cell cultures. In primary cultures of epithelial cells, MFG-E8 intracellular protein expression was evaluated in absence or presence of PRL (0.2 and 1 μg/ml). The results show that MFG-E8 protein is almost exclusively localized to the epithelium in whole endometrial biopsies. Both MFG-E8 mRNA and protein expression increased in the luteal phase and were highest during the WOI; epithelial protein location of αvβ3 integrin also peaked on cycle Day 24. Cultured epithelial cells showed a diffuse staining of MFG-E8 over the cytoplasmic area; however, some cells presented a punctuated staining pattern. PRL treatment of epithelial cells for 72 h in vitro significantly increased MFG-E8 protein intracellular expression. This is the first report on MFG-E8 protein localization to the human endometrial epithelium and its up-regulation during the WOI. The pattern of glandular expression of its ligand αvβ3 integrin was remarkably similar. In vitro data support a modulatory role for PRL as a stromal/epithelial paracrine factor controlling MFG-E8.

Epithelial cell protein milk fat globule-epidermal growth factor 8 and human chorionic gonadotropin regulate stromal cell apoptosis in the human endometrium.

OBJECTIVE To study the regulation of apoptosis in human endometrial cells. The specific aims were to determine whether milk fat globule-epidermal growth factor 8 (MFG-E8), a novel endometrial epithelial protein, modulates caspase activation and DNA fragmentation; and to examine whether hCG, an early embryonic product, regulates Bax and Bcl-2 equilibrium, as well as MFG-E8 expression. DESIGN Primary cultures of human endometrial epithelial cells (EECs) and endometrial stromal cells (ESCs). SETTING Academic center. PATIENT(S) Ovulatory women aged 21-30 years. INTERVENTION(S) Treatment with MFG-E8 and hCG. MAIN OUTCOME MEASURE(S) Apoptotic activity was quantified using a luciferase assay. Deoxyribonucleic acid fragmentation was detected by TUNEL assay. Bax, Bcl-2, and MFG-E8 messenger RNA expression levels were determined by quantitative reverse transcription-polymerase chain reaction. Immunocytochemistry was used to establish cell purity and presence of MFG-E8 and hCG-R (receptor) proteins. RESULT(S) Endometrial epithelial cells were cytokeratin(+), vimentin(-), MFG-E8(+), and hCG-R(+), whereas ESC were vimentin(+), cytokeratin(-), MFG-E8(-), and hCG-R(+). Treatment of ESC with MFG-E8 resulted in a 13-fold increase in caspase activity and a 30-fold increase in TUNEL. On the other hand, hCG decreased messenger RNA expression of Bax in ESC. CONCLUSION(S) Milk fat globule-epidermal growth factor 8 has proapoptotic activity, suggesting participation in endometrial remodeling via an epithelial-stromal cell paracrine effect. Conversely, pregnancy levels of hCG has opposite effects on stromal cells.