Katsunori Shimamura

Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate

Abstract:  We investigated the relationship between oxidative stress and poor oocyte quality and whether the antioxidant melatonin improves oocyte quality. Follicular fluid was sampled at oocyte retrieval during in vitro fertilization and embryo transfer (IVF‐ET). Intrafollicular concentrations of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) in women with high rates of degenerate oocytes were significantly higher than those with low rates of degenerate oocytes. As there was a negative correlation between intrafollicular concentrations of 8‐OHdG and melatonin, 18 patients undergoing IVF‐ET were given melatonin (3 mg/day), vitamin E (600 mg/day) or both melatonin and vitamin E. Intrafollicular concentrations of 8‐OHdG and hexanoyl‐lysine adduct were significantly reduced by these antioxidant treatments. One hundred and fifteen patients who failed to become pregnant with a low fertilization rate (50%) in the previous IVF‐ET cycle were divided into two groups during the next IVF‐ET procedure; 56 patients with melatonin treatment (3 mg/day) and 59 patients without melatonin treatment. The fertilization rate was improved by melatonin treatment compared to the previous IVF‐ET cycle. However, the fertilization rate was not significantly changed without melatonin treatment. Oocytes recovered from preovulatory follicles in mice were incubated with H2O2 for 12 hr. The percentage of mature oocytes with a first polar body was significantly reduced by addition of H2O2 (300 μm). The inhibitory effect of H2O2 was significantly blocked by simultaneous addition of melatonin. In conclusion, oxidative stress causes toxic effects on oocyte maturation and melatonin protects oocytes from oxidative stress. Melatonin is likely to improve oocyte quality and fertilization rates.

Endometrial growth and uterine blood flow: a pilot study for improving endometrial thickness in the patients with a thin endometrium

OBJECTIVE To examine whether thin endometria can be improved by increasing uterine radial artery (uRA) blood flow. DESIGN A prospective observational study. SETTING University hospital and city general hospital. PATIENT(S) Sixty-one patients with a thin endometrium (endometrial thickness [EM] <8 mm) and high radial artery-resistance index of uRA (RA-RI >or=0.81). INTERVENTION(S) Vitamin E (600 mg/day, n = 25), l-arginine (6 g/day, n = 9), or sildenafil citrate (100 mg/day, intravaginally, n = 12) was given. MAIN OUTCOME MEASURE(S) EM and RA-RI were assessed by transvaginal color-pulsed Doppler ultrasound. RESULT(S) Vitamin E improved RA-RI in 18 (72%) out of 25 patients and EM in 13 (52%) out of 25 patients. L-arginine improved RA-RI in eight (89%) out of nine patients and EM in six (67%) patients. Sildenafil citrate improved RA-RI and EM in 11 (92%) out of 12 patients. In the control group (n = 10), who received no medication to increase uRA-blood flow, only one (10%) patient improved in RA-RI and EM. The effect of vitamin E was histologically examined in the endometrium (n = 5). Vitamin E improved the glandular epithelial growth, development of blood vessels, and vascular endothelial growth factor protein expression in the endometrium. CONCLUSION(S) Vitamin E, l-arginine, or sildenafil citrate treatment improves RA-RI and EM and may be useful for the patients with a thin endometrium.

Protective role of melatonin in progesterone production by human luteal cells.

Abstract:  This study investigated whether melatonin protects luteinized granulosa cells from reactive oxygen species (ROS) as an antioxidant to enhance progesterone production in the follicle during ovulation. Follicular fluid was sampled at the time of oocyte retrieval in women undergoing in vitro fertilization and embryo transfer (IVF‐ET). Melatonin concentrations in the follicular fluid were positively correlated with progesterone concentrations (r = 0.342, P < 0.05) and negatively correlated with the concentration of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG), an oxidative stress marker (r = −0.342, P < 0.05). The progesterone and 8‐OHdG concentrations were negatively correlated (r = −0.246, P < 0.05). Luteinized granulosa cells were obtained at the time of oocyte retrieval in women undergoing IVF‐ET. Cells were incubated with H2O2 (30, 50, 100 μm) in the presence or absence of melatonin (1, 10, 100 μg/mL). Progesterone production by luteinized granulosa cells was significantly inhibited by H2O2. Melatonin treatment overcame the inhibitory effect of H2O2. Twenty‐five patients who had luteal phase defect (serum progesterone concentrations <10 ng/mL during the mid‐luteal phase) were divided into two groups during the next treatment cycle: 14 women were given melatonin (3 mg/day at 22:00 hr) throughout the luteal phase and 11 women were given no medication as a control. Melatonin treatment improved serum progesterone concentrations (>10 ng/mL during the mid‐luteal phase) in nine of 14 women (64.3%), whereas only two of 11 women (18.1%) showed normal serum progesterone levels in the control group. In conclusion, melatonin protects granulosa cells undergoing luteinization from ROS in the follicle and contributes to luteinization for progesterone production during ovulation.

Changes in blood-flow impedance of the human corpus luteum throughout the luteal phase and during early pregnancy

OBJECTIVE To examine changes in blood flow in the corpus luteum throughout the luteal phase and during early pregnancy. DESIGN Longitudinal and cross-sectional prospective studies. SETTING University hospital and city general hospital. PATIENT(S) Sixty-one women with normal menstrual cycles and normal luteal function, 13 women with hCG-induced ovulatory cycle, 10 women with luteal phase defect, six women with luteinized unruptured follicle (LUF), and 17 pregnant women (4-10 weeks of gestation). INTERVENTION(S) Blood-flow impedance in the corpus luteum was assessed by transvaginal color-pulsed Doppler ultrasound. MAIN OUTCOME MEASURES Resistance index (RI) in the corpus luteum. RESULT(S) In the normal menstrual cycle, the RI of the preovulatory follicle was high and significantly decreased after ovulation. Luteal-RI further decreased during the early to midluteal phase but significantly increased during the late luteal phase. Those changes in luteal-RI were similar to those of the hCG-induced ovulatory cycle. Luteal-RI during the midluteal phase was significantly higher in the patients with luteal phase defect than in women with normal luteal function. Luteal-RI of the LUF patients remained high throughout the luteal phase. In pregnant women, luteal-RI remained at the midluteal phase level until 7 weeks of gestation and significantly increased thereafter. CONCLUSION(S) The change in luteal-RI was associated with corpus luteum development and corpus luteum regression. Luteal-RI was closely associated with luteal function.

Luteal blood flow and luteal function

BackgroundBlood flow in the corpus luteum (CL) is associated with luteal function. The present study was undertaken to investigate whether luteal function can be improved by increasing CL blood flow in women with luteal phase defect (LFD).MethodsBlood flow impedance in the CL was measured by transvaginal color-pulsed-Doppler-ultrasonography and was expressed as a resistance index (RI). The patients with both LFD [serum progesterone (P) concentrations < 10 ng/ml during mid-luteal phase] and high CL-RI (≥ 0.51) were given vitamin-E (600 mg/day, n = 18), L-arginine (6 g/day, n = 14) as a potential nitric oxide donor, melatonin (3 mg/day, n = 13) as an antioxidant, or HCG (2,000 IU/day, n = 10) during the subsequent menstrual cycle.ResultsIn the control group (n = 11), who received no medication to increase CL blood flow, only one patient (9%) improved in CL-RI and 2 patients (18%) improved in serum P. Vitamin-E improved CL-RI in 15 patients (83%) and improved serum P in 12 patients (67%). L-arginine improved CL-RI in all the patients (100%) and improved serum P in 10 patients (71%). HCG improved CL-RI in all the patients (100%) and improved serum P in 9 patients (90%). Melatonin had no significant effect.ConclusionVitamin-E or L-arginine treatment improved luteal function by decreasing CL blood flow impedance. CL blood flow is a critical factor for luteal function.

Melatonin as a new drug for improving oocyte quality

BackgroundAlthough recent technical advances have benefited infertile couples, inadequate embryo development as a result of poor quality oocytes still contributes to infertility. The purpose of the present study was to evaluate melatonin as a drug for improving oocyte quality in such cases.MethodsTwenty-seven women from whom fewer than three fertilized embryos were grown and who failed to fall pregnant in previous treatment cycles were enrolled in the current prospective clinical study. Subjects took 1 mg or 3 mg tablets of melatonin orally at 22:00 h from the fifth day of the previous menstrual cycle to the day they were injected with human chorionic gonadotropin. The numbers of mature follicles, retrieved oocytes, degenerate oocytes, and fertilized embryos were compared to their previous data without melatonin (the control cycle).ResultsIntrafollicular melatonin concentrations were significantly increased, and intrafollicular lipid peroxide concentrations showed a tendency towards lower levels in the 3 mg melatonin treatment cycles compared with the control cycles. The number of degenerate oocytes was significantly reduced, and the number of fertilized embryos showed a tendency towards an increase in the 3 mg cycle compared to the control cycle. Three women succeeded in falling pregnant.ConclusionMelatonin is likely to become the drug of choice for improving oocyte quality in women who cannot fall pregnant because of poor quality oocytes.

Luteal blood flow in patients undergoing GnRH agonist long protocol.

BackgroundBlood flow in the corpus luteum (CL) is closely related to luteal function. It is unclear how luteal blood flow is regulated. Standardized ovarian-stimulation protocol with a gonadotropin-releasing hormone agonist (GnRHa long protocol) causes luteal phase defect because it drastically suppresses serum LH levels. Examining luteal blood flow in the patient undergoing GnRHa long protocol may be useful to know whether luteal blood flow is regulated by LH.MethodsTwenty-four infertile women undergoing GnRHa long protocol were divided into 3 groups dependent on luteal supports; 9 women were given ethinylestradiol plus norgestrel (Planovar) orally throughout the luteal phase (control group); 8 women were given HCG 2,000 IU on days 2 and 4 day after ovulation induction in addition to Planovar (HCG group); 7 women were given vitamin E (600 mg/day) orally throughout the luteal phase in addition to Planovar (vitamin E group). Blood flow impedance was measured in each CL during the mid-luteal phase by transvaginal color-pulsed-Doppler-ultrasonography and was expressed as a CL-resistance index (CL-RI).ResultsSerum LH levels were remarkably suppressed in all the groups. CL-RI in the control group was more than the cutoff value (0.51), and only 2 out of 9 women had CL-RI values < 0.51. Treatments with HCG or vitamin E significantly improved the CL-RI to less than 0.51. Seven of the 8 women in the HCG group and all of the women in the vitamin E group had CL-RI < 0.51.ConclusionPatients undergoing GnRHa long protocol had high luteal blood flow impedance with very low serum LH levels. HCG administration improved luteal blood flow impedance. This suggests that luteal blood flow is regulated by LH.

Usefulness of intermittent clomiphene citrate treatment for women with polycystic ovarian syndrome that is resistant to standard clomiphene citrate treatment

Clomiphene citrate (CC) has been used as a first‐line treatment for anovulatory polycystic ovary syndrome (PCOS). However, some patients with PCOS are resistant to standard CC treatment. In this study, a new CC treatment protocol was developed, named “intermittent CC treatment” (ICT) and its efficacy was investigated on the induction of follicular growth in patients with PCOS who were resistant to standard CC treatment.