Celso Silva

The first polar body does not predict accurately the location of the metaphase II meiotic spindle in mammalian oocytes

OBJECTIVE To evaluate how well polar body location predicts spindle localization and to examine spindle morphology. DESIGN Randomized, controlled animal study. SETTING University-affiliated research laboratory. ANIMAL(S) Mature, female golden hamsters. INTERVENTION(S) After superovulation with pregnant mare serum gonadotropin and hCG, metaphase II oocytes were obtained and imaged under digital polarization microscopy. MAIN OUTCOME MEASURE(S) Identify the meiotic spindle in living, unfixed hamster oocytes and determine spindle location relative to the polar body. RESULT(S) Spindles were imaged in 30 oocytes and only in 5 of them could the polar body predict the spindle localization. In the remaining oocytes, the spindles presented a random distribution within the cytoplasm. CONCLUSION(S) These data show that the polar body location is not an accurate predictor for meiotic spindle location in mammalian oocytes.

Imaging meiotic spindles by polarization light microscopy: principles and applications to IVF

Meiotic spindles tether the chromosomes of oocytes and have been found to be structurally abnormal in older women. Conventional methods to image the meiotic spindle, such as immunostaining or transmission electron microscopy, require prior fixation, so they cannot be used clinically, and their utility in developmental studies is limited. Spindles can also be imaged non-invasively based on their birefringence, an inherent optical property of highly ordered molecules, such as microtubules, as they are illuminated with polarized light. Polarized light microscopy has been gainfully applied to embryology for decades, but recently a digital, orientation-independent polarized light microscope, the polscope, has demonstrated the exquisite sensitivity needed to image the low levels of birefringence exhibited by mammalian spindles. Its use of nearly circularly polarized light also produces orientation-independent measures of spindle birefringence, thus providing a method to quantify spindle architecture in living oocytes. The safety and utility of polscope imaging has been demonstrated in mammalian oocytes, including those from women undergoing ICSI. Spindle imaging with the polscope provides structural information closely related to the more invasive immunostaining method, and also enables study of the dynamic architecture of spindles. Profound effects of cooling on meiotic spindles have also been shown, and polscope imaging has been used to optimize thermodynamic stability of oocytes during ICSI. It has been shown that embryos derived from oocytes with normal, intact meiotic spindles exhibit superior development after fertilization and in-vitro culture. The mechanisms underlying age-related disruption of meiotic spindles in women remain unclear, but may relate to factors residing within the chromosomes themselves, since mice engineered to shorten their telomeres exhibit structurally abnormal spindles in their oocytes, and their embryos undergo cell cycle arrest and apoptosis, a phenotype remarkably similar to that observed in oocytes and embryos from older women. A time-lapse video of a mouse oocyte imaged by polscope may be purchased for viewing on the internet at www.rbmonline.com/Article/824 (free to web subscribers).

The transfer point is a novel measure of embryo placement

OBJECTIVE To study the relationship between IVF-ET pregnancy outcomes and measures of embryo placement. DESIGN Case-control study. SETTING Tertiary care center. PATIENT(S) Twenty-three patients who underwent two ultrasonography-guided ETs, of which one resulted in a clinical pregnancy and the other did not. MAIN OUTCOME MEASURES Point of embryo placement normalized to the endometrial cavity length (the transfer point), distance from the point of embryo placement to the uterine fundus, time required for ET, contact with the uterine fundus, and evidence of trauma. Videotaped ETs were quantitatively analyzed. RESULT(S) From February 1, 2000, to March 31, 2001, videotaped ETs from 23 pairs of pregnant and nonpregnant cycles were identified. Embryo placement was more shallow in pregnancy cycles than in nonpregnancy cycles. The groups did not differ in the absolute distance of embryo placement to the fundus, ovarian stimulation, or other features of the ET. CONCLUSION(S) The transfer point may serve as a better marker of embryo position than does the absolute distance to the uterine fundus.

Inflammatory biomarkers and telomere length in women with polycystic ovary syndrome.

OBJECTIVE To analyze whether leukocyte telomere length (LTL) is impaired in women with polycystic ovary syndrome (PCOS). DESIGN Case-control study. SETTING Hospital. PATIENT(S) A total of 274 women, including 150 patients with PCOS and 124 controls. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Body mass index (BMI), waist circumference, systemic arterial pressure, lipid profile, E(2), LH, T, androstenedione, PRL, TSH, sex hormone-binding globulin, C-reactive protein (CRP), homocysteine, free androgen index, and the homeostatic model of insulin sensitivity (HOMA-IR) index were analyzed. The LTL evaluation was measured by quantitative polymerase chain reaction. RESULT(S) The PCOS group had higher values for weight, BMI, waist circumference, systolic arterial pressure, triglycerides, LH, T, insulin, CRP, free androgen index, and HOMA-IR compared with the control group. Sex hormone-binding globulin and E(2) levels were lower in the PCOS group than in the control group. The LTL did not differ between groups. Age, BMI, and HOMA-IR had no significant effect on LTL. The inflammatory biomarkers CRP and homocysteine were negatively correlated with LTL in patients with PCOS. CONCLUSION(S) Our results showed no differences in LTL between patients with PCOS and controls, but CRP and homocysteine biomarkers negatively correlated with LTL in the PCOS group.