Temporal and receptor correlates of the estrogen response in sheep

Transrectal Doppler sonography of uterine blood flow

Transrectal Doppler ultrasound was used for the noninvasive investigation of uterine blood flow in cows. Both the left and right Aa. uterinae were scanned to obtain blood flow velocity waveforms over 2 consecutive estrous cycles. Blood flow was reflected by the resistance index (RI) and the time-averaged maximum velocity (TAMV). Intra-observer reproducibility of Doppler measurements was evaluated. The intra-class correlation coefficient (Intra-CC) was 0.97 for the RI and 0.95 for TAMV. While RI values did not differ between the left and right A. uterina (P > 0.05), differences in TAMV occurred between both vessels in 2 cows. These differences were not related to the ovary bearing the dominant follicle or to the corpus luteum (P < 0.001). As in all cows, changes of RI and TAMV values between the left and right artery during the estrous cycle were correlated (correlation coefficient r > 0.72; P < 0.0001); the mean values of both sides were used for subsequent analyses. Variance component estimates for the effect of cow on RI and TAMV were 8 and 13% and for the influence of day of estrous cycle they were 70 and 47%, respectively (P <0.0001). Between estrous cycles no significant differences could be measured within cows (P > 0.05). The highest RI and lowest TAMV values occurred on Day 0 (= day of ovulation) and Day 1, while the lowest RI and highest TAMV values were measured between Days -3 and -1 of the estrous cycle, respectively. There was a positive correlation between TAMV and estrogen concentrations and a negative correlation between RI and plasma estrogen levels. Plasma progesterone levels and TAMV were negatively correlated, but no correlation could be measured (P > 0.05) between RI values and plasma progesterone concentrations. While there were no differences in plasma concentrations of estrogens and progesterone between estrous cycles within cows, the levels of these hormones differed between cows. The results show that transrectal Doppler sonography is a useful, noninvasive method for examining uterine blood flows in cows. If there is an influence of uterine perfusion on fertility in cows its role needs further investigation.

Relaxin secretion by human granulosa cell culture is predictive of in-vitro fertilization-embryo transfer success

We have developed a cell culture system for human luteinizing granulosa cells which supports the timely and dynamic secretion of oestrogen, progesterone and relaxin in patterns that mimic serum concentrations of these hormones during the luteal phase of the menstrual cycle. There was a wide variation in the amount of relaxin secreted by the cultured cells for the 69 patients studied. As relaxin production was generally maximal by day 10 of culture, comparisons were made at this time point. It was observed that most of the conceptions occurred in patients with higher relaxin secretion in vitro. All cycles with relaxin > 800 pg/ml on day 10 had a term pregnancy while only 13% of cycles with relaxin < 200 pg/ml had term pregnancies. A limited number of cycles from donor/recipient cycles did not show similar results. Steroid concentrations were not predictive of conception. These results demonstrated that in-vitro production of relaxin is predictive of implantation success in in-vitro fertilization (IVF)-embryo transfer cycles. This supports the hypothesis that relaxin may be involved in implantation and that lowered relaxin concentrations may be a partial cause of poor pregnancy rates after IVF.

Effects of estradiol and progesterone on the reproductive tract and on uterine sex steroid receptors in female lambs

The effects of estradiol-17 beta (E(2)) and progesterone (P) on the reproductive tract and on uterine estrogen receptors and P receptors were studied in 2-mo-old female lambs (n = 11). On Days 0, 1 and 2, E(2) (1 ug/kg, Group E, n = 4), P (0.3 mg/kg, Group P, n = 4) or corn oil (control) vehicle (Group C, n = 3) were administered, and in Day 3 all lambs were slaughtered. Group E (n = 12) had E(2) serum concentrations (mean +/- SEM) of 43.8 +/- 2.2 pmol L , similar to that of the follicular phase; while P concentrations in Group P (n = 12) were similar (2.8 +/- 0.18 nmol L ) to those of the luteal phase of the ewe estrous cycle. The E(2) treatment increased the reproductive tract weight, while P treatment increased only the uterine weight. Both E(2) and P receptors from upper and middle uterine zones (including the myometrium, endometrium and caruncles) were determined by binding assays with tritiated hormones, dextran-charcoal separation and inverse Scatchard analysis. Both the E(2) and P treatments decreased E(2) and P receptor concentrations in upper and middle zones, although the upper zone had higher receptor concentrations than the middle zone (P < 0.01). E(2) receptor concentrations in the upper zone (mean +/- SEM, fmol mg prot) were 1236 +/- 34, 667 +/- 80 and 444 +/- 103 for Groups C, P and E, respectively. The P receptor concentrations were 2434 +/- 135, 1273 +/- 102 and 1536 +/- 213 for the same groups. The high uterine P receptor concentrations allowed P action without prior estrogen priming of female lambs. The present results suggest that E(2) and P might down-regulate their own and each other's receptors during development. The biological responses induced by E(2) and P, as measured by the reproductive tract weight, demonstrated that at an early stage of development uterine receptors are physiologically active.

Vaginal color Doppler assessment of uterine artery impedance correlates with immunohistochemical markers of endometrial receptivity required for the implantation of an embryo

OBJECTIVE

To investigate the correlation between uterine artery impedance with immunohistochemical histologic, and ultrasonographic markers of uterine receptivity.

DESIGN

A prospective study of subfertile women undergoing a frozen embryo replacement cycle.

SETTING

A tertiary infertility clinic.

PATIENTS

The study was based on 86 patients who had failed to become pregnant during a standard IVF treatment cycle and who had at least two good quality embryos cryopreserved.

INTERVENTIONS

All patients had pituitary desensitization with the GnRH analogue buserelin acetate, followed by E2 and P replacement therapy. Vaginal color Doppler images of both uterine arteries were obtained on days 7, 14, and 21 of the first (trial) cycle. On day 21, an endometrial biopsy was taken for dating a 24-kd protein, placental protein 14, and E2 receptor assessment. After a menstrual bleed had been induced, administration of estrogen and P was reinstituted and embryos transferred to the uterus on the 3rd or 4th day of P administration.

MAIN OUTCOME MEASURES

The mean pulsatility index of the left and right uterine arteries, a semiquantitative score of endometrial 24-kd protein, PP14, and E2 receptor assessment, endometrial histologic dating, and pregnancy outcome.

RESULTS

Nineteen of 76 patients who had a successful ET became pregnant. The pulsatility index on day 14 of both the trial and ET cycles was significantly lower in those who achieved pregnancy as compared with those who did not conceive: 2.65 (range 1.3 to 3.4) versus 3.85 (1.8 to 6.8) and 2.85 (1.4 to 3.6) versus 4.15 (2.1 to 6.8), respectively. There were significant correlations between pulsatility index and 24-kd protein, E2 receptor, and endometrial histology but not with PP14 and endometrial thickness.

CONCLUSIONS

Uterine artery impedance has a significant correlation with biochemical markers of uterine receptivity and accurately predicts the probability of pregnancy in frozen embryo replacement cycles. It is a useful method for assessing uterine receptivity in assisted conception programs.

Systemic and uterine responses to chronic infusion of estradiol-17 beta

Human and ovine pregnancies are associated with increases in plasma levels of estrogens and angiotensin II (ANG II), cardiac output (CO), blood volume (BV), and uterine blood flow (UBF), as well as attenuated ANG II pressor responses. We hypothesized that, in nonpregnant animals, prolonged estradiol-17 beta (E2 beta) treatment would reproduce these endocrine and hemodynamic alterations. Nonpregnant ovariectomized ewes (n = 5) received 5 microgram E2 beta/kg iv followed by 220 micrograms/day for 14 days. Plasma E2 beta increased from 36 +/- 6 to 269 +/- 79 (SE) pg/ml (P < 0.05) during E2 beta treatment, returning to control values 4 days posttreatment. By 3 days of E2 beta, mean arterial pressure (MAP) and systemic vascular resistance (SVR) fell 9 +/- 1 and 29 +/- 1%, whereas heart rate (HR) and CO increased 20 +/- 5 and 26 +/- 1% (P < 0.05). Stroke volume (SV), BV, and plasma volume were unchanged until 7 days of E2 beta, with values rising 17 +/- 5, 13 +/- 3, and 14 +/- 4, respectively (P < 0.05). Although MAP remained similarly depressed (-11 +/- 1%) during week 2 of E2 beta, SVR decreased further (-37 +/- 3%) and was associated with additional increases (P < 0.05) in CO to 44 +/- 5%, reflecting rises in SV (21 +/- 2%) but not HR. Increases in BV correlated with rises in CO (r = 0.55) and SV (r = 0.64) but not HR (r = -0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

The use of transvaginal color flow imaging after in vitro fertilization to identify optimum uterine conditions before embryo transfer

OBJECTIVE

To assess whether a measure of uterine blood flow impedance (the pulsatility index, PI) as determined by transvaginal ultrasonography with color blood flow imaging, may be used to assess endometrial receptivity immediately before the time of embryo transfer (ET) after assisted conception.

DESIGN

A prospective study of infertile women who had undergone treatment to induce multiple follicular development followed by ultrasound-guided oocyte retrieval. The oocytes were fertilized in vitro.

SETTING

The Hallam Medical Centre.

PATIENTS

Eight-two women (22 to 44 years of age) who all had three or four good quality embryos available for transfer to the uterus.

INTERVENTIONS

All women were examined by transvaginal ultrasonography, with color flow imaging and blood flow analysis, immediately before ET.

MAIN OUTCOME MEASURES

The mean PI of the left and right uterine arteries, the pregnancy rate (PR) (%), the embryo implantation rate (%), and the multiple PR (%).

RESULTS

The patients were grouped according to whether the PI was low (1.00 to 1.99), medium (2.00 to 2.99), or high (3+). There were 27 women in the low PI group, 36 in the medium, and 19 in the high. The PR (%), embryo implantation rate (%), and multiple PR (%) were 41%, 15.3%, and 27.3% for the low PI group and 47%, 22.2%, and 47.1% for the medium PI group. There were no pregnancies in the high PI group. Thus 35% (19/54) of women who failed to become pregnant had a PI value greater than 3.0.

CONCLUSIONS

These data suggest that the PI value on the day of ET could be used to: (1) increase the implantation rate by showing which embryos should be cryopreserved until the uterus is more receptive and (2) reduce the multiple PR by indicating that the number of embryos transferred should be limited when the uterus is most receptive.