Effect of coenzyme Q(10) and alpha-tocopherol content of mitochondria on the production of superoxide anion radicals

The effects of coenzyme Q(10) (CoQ(10)) and alpha-tocopherol on the rate of mitochondrial superoxide anion radical (O2(./-)) generation were examined in skeletal muscle, liver, and kidney of 24-month-old mice. Mice were orally administered alpha-tocopherol (200 mg.kg(-1).day(-1)) alone, CoQ(10) (123 mg.kg(-1).day(-1)) alone, or the two together for 13 wk. Administration of alpha-tocopherol resulted in an approximately sevenfold elevation of mitochondrial alpha-tocopherol content. Intake of CoQ(10) alone caused an approximately fivefold increase in CoQ content (CoQ(9) and/or CoQ(10)) and alpha-tocopherol of mitochondria. The rate of (O2(./-)) generation by submitochondrial particles (SMPs) was inversely related to their alpha-tocopherol content but unrelated to CoQ content. Experimental in vitro augmentation of SMPs with varying amounts of alpha-tocopherol caused an up to approximately 50% decrease in the rate of O2(./-) generation. Similar in vitro augmentations of SMPs with CoQ(10) had previously been found to have no effect on the rate of O2(./-) generation The CoQ(10)-induced elevation of alpha-tocopherol in the present study was inferred to be due to a 'sparing/regeneration' by CoQ. Results indicate the involvement of alpha-tocopherol in the elimination of mitochondrially generated O2(./-)

How useful is cervical dilatation in patients with cervical stenosis who are participating in an in vitro fertilization-embryo transfer program? The Bourn Hall experience

OBJECTIVE

To evaluate the place of cervical dilatation performed at the initial visit in an IVF-ET cycle in patients with known cervical stenosis.

DESIGN

Retrospective study.

SETTING

A tertiary care assisted conception unit.

PATIENT(S)

Fifty-seven patients who failed to conceive after a previous ET attempt and in whom the ET was classified as "difficult."

INTERVENTION(S)

Cervical dilatation under general anesthesia after pituitary suppression and before gonadotropin stimulation.

MAIN OUTCOME MEASURE(S)

Ease of the ET procedure and clinical pregnancy rate.

RESULT(S)

Eighteen (31.6%) of 57 women who failed to conceive after a previous attempt at IVF-ET achieved a clinical pregnancy after cervical dilatation. In 40 patients (70.2%), the subsequent ET was classified as "easy," whereas in the other 17 (29.8%), it remained difficult. The pregnancy rate was significantly higher when the ET was easy than when it was difficult (40% versus 11.8%, P<.05).

CONCLUSION(S)

In patients with cervical stenosis and a previous difficult ET, cervical dilatation during the initial visit leads to an easier subsequent ET and improves the pregnancy rate.

The effect of endometrial polyps on outcomes of in vitro fertilization (IVF) cycles

PURPOSE

Our purpose was to investigate the effect of endometrial polyps on pregnancy outcome in an in vitro fertilization (IVF) program.

METHODS

Endometrial polyps less than 2 cm in diameter were suspected by transvaginal ultrasound before oocyte recovery in 83 patients. Forty-nine women (Group I) had standard IVF-embryo transfer, while in 34 women (Group II) hysteroscopy and polypectomy were performed immediately following oocyte retrieval, the suitable embryos were all frozen, and the replacement cycle took place a few months later.

RESULTS

Of the 32 hysteroscopies, a polyp was diagnosed in 24 cases (75%) and polypoid endometrium in another 5 patients (15.6%). An endometrial polyp was confirmed by histopathological examination in 14 women (58.3%). The pregnancy rate in group I was similar to the general pregnancy rate of our unit over the same period (22.4 vs 23.4%) but the miscarriage rate was higher (27.3 vs 10.7%, P = 0.08). In Group II, the pregnancy and miscarriage rates were similar to those of the frozen embryo cycles at Bourn Hall (30.4 and 14.3 vs 22.3 and 12.1%, respectively).

CONCLUSIONS

Small endometrial polyps, less than 2 cm, do not decrease the pregnancy rate, but there is a trend toward increased pregnancy loss. A policy of oocyte retrieval, polypectomy, freezing the embryos, and replacing them in the future might increase the "take-home baby" rate.

The fertility potential of women with a single ovary

The incidence of having a single ovary is quite common in infertile patients and can reach up to 17% of women with severe tubal disease who require in-vitro fertilization (IVF) treatment. Data on the short- and long-term implications of having only one ovary are scarce, and patients in this situation are naturally concerned. This article reviews the effect of possessing a single ovary on the fertility potential and ovarian reserve of these women and their performance in assisted reproduction treatment.

Comparisons of coenzyme Q bound to mitochondrial membrane proteins among different mammalian species

The objective of this study was to elucidate the mechanisms that govern the variations in the rates of mitochondrial superoxide anion radical (O2-*) generation in different species. The amounts of coenzyme Q (CoQ) associated with mitochondrial membrane proteins were compared in five different mammalian species, namely mouse, rat, rabbit, pig, and cow. Micelles of cardiac mitochondria were prepared using Triton X-100 or deoxycholate (DOC) as detergents, and the micelles containing mitochondrial proteins were sedimented by sucrose density ultracentrifugation. The amount of CoQ present in both types of micelles varied in different species, whereas alpha-tocopherol, another lipoidal molecule in mitochondrial membranes, could not be detected in the micelles of any of these species. The amounts of CoQ bound to mitochondrial proteins in DOC micelles were higher in those mammalian species where CoQ10 was the predominant CoQ homologue, and the amounts were found to be inversely correlated with the rate of mitochondrial 02-* generation among different species. Results also indicated that mitochondrial CoQ exists in at least two distinct pools, one of which is associated with the membrane proteins. The degree of association between CoQ and membrane proteins appears to be a factor determining the rate of mitochondrial O2-* generation.

Effects of coenzyme Q10 and alpha-tocopherol administration on their tissue levels in the mouse: elevation of mitochondrial alpha-tocopherol by coenzyme Q10

Coenzyme Q (CoQ) was previously demonstrated in vitro to indirectly act as an antioxidant in respiring mitochondria by regenerating alpha-tocopherol from its phenoxyl radical. The objective of this study was to determine whether CoQ has a similar sparing effect on alpha-tocopherol in vivo. Mice were administered CoQ10 (123 mg/kg/day) alone, or alpha-tocopherol (200 mg/kg/day) alone, or both, for 13 weeks, after which the amounts of CoQ10, CoQ9 and alpha-tocopherol were determined by HPLC in the serum as well as homogenates and mitochondria of liver, kidney, heart, upper hindlimb skeletal muscle and brain. Administration of CoQ10 and alpha-tocopherol, alone or together, increased the corresponding levels of CoQ10 and alpha-tocopherol in the serum. Supplementation with CoQ10 also elevated the amounts of the predominant homologue CoQ9 in the serum and the mitochondria. A notable effect of CoQ10 intake was the enhancement of alpha-tocopherol in mitochondria. alpha-Tocopherol administration resulted in an elevation of alpha-tocopherol content in the homogenates of nearly all tissues and their mitochondria. Results of this study thus indicate that relatively long-term administration of CoQ10 or alpha-tocopherol can result in an elevation of their concentrations in the tissues of the mouse. More importantly, CoQ10 intake has a sparing effect on alpha-tocopherol in mitochondria in vivo.

The role of ovarian volume in reproductive medicine

The human ovary is a dynamic organ which continually changes in size and activity through life, as an integral part of the changes that the female is going through before during and after her reproductive life. Following the rapid increase in the use of transvaginal scan in recent years, the measurement of ovarian volume has become quick, accurate and cost-effective. Ovarian volume is an important tool in the screening, diagnosis and monitoring the treatment of conditions such as polycystic ovarian syndrome, ovarian cancer and adolescent abnormalities. In reproductive medicine, measurement of ovarian volume has a role in the assessment of ovarian reserve and prediction of response to superovulation.

A sensitive chemiluminescence method to measure the lipoxygenase catalyzed oxygenation of complex substrates

Oxidative modification of low-density lipoprotein (LDL) has been implicated as a patho-physiological process in early atherogenesis and 15-lipoxygenases (15-LOX) may be involved. While studying the in vitro kinetics of the 15-LOX/LDL interaction, we found that the conventional spectrophotometric assays failed in the range of substrate saturation owing to the high optical density of concentrated LDL solutions. Therefore, we developed a much more sensitive assay system which was based on peroxide induced isoluminol enhanced chemiluminescence. With this method reliable kinetic data were obtained at LDL concentrations of up to 1 mg/ml. To validate this luminometric method the kinetic parameters of 15-LOX catalyzed oxygenation of linoleic acid (Km=3.7 microM, kcat=17 s-1) were determined and we observed a good agreement with previously published data obtained with a spectrophotometric assay. Moreover, we found that the kinetic constants of 15-LOX catalyzed LDL oxidation (Km=0.64 microM, kcat=0.15 s-1) are quite different from those of free fatty acid oxygenation and that the cholesterol esters are preferentially oxidized during 15-LOX/LDL interaction. Vitamin E depletion does not reduce the rate of LDL oxidation and analysis of the structure of the oxygenation products suggests that the majority of the products were formed via direct LOX catalyzed oxidation of LDL ester lipids. The luminometric method described here is not restricted to the measurement of LOX catalyzed LDL oxidation, but may also be used to determine kinetic constants for the oxidation of other complex substrates such as biomembranes or liposomes.

Mitochondrial coenzyme Q content and aging

The main objective of this study was to determine the nature of the relationship between aging and mitochondrial coenzyme Q (CoQ) content. Mitochondria in the heart, skeletal muscle, kidney and brain of the mouse varied in both the amount of total CoQ (CoQ9 + CoQ10) content as well as in the ratio of the CoQ9 to CoQ10. CoQ content declined with age only in the skeletal muscle. Caloric restriction (CR) resulted in an increase in the amount of CoQ9 in skeletal muscle mitochondria. This effect was partially reversible upon termination of the caloric restriction regimen. Results suggest that a decrease in mitochondrial CoQ content is an integral aspect of aging in skeletal muscle.

Caloric restriction prevents age-associated accrual of oxidative damage to mouse skeletal muscle mitochondria

The purpose of this study was to understand the nature of the causes underlying the senescence-related decline in skeletal muscle mass and performance. Protein and lipid oxidative damage to upper hindlimb skeletal muscle mitochondria was compared between mice fed ad libitum and those restricted to 40% fewer calories--a regimen that increases life span by approximately 30-40% and attenuates the senescence-associated decrement in skeletal muscle mass and function. Oxidative damage to mitochondrial proteins, measured as amounts of protein carbonyls and loss of protein sulfhydryl content, and to mitochondrial lipids, determined as concentration of thiobarbituric acid reactive substances, significantly increased with age in the ad libitum-fed (AL) C57BL/6 mice. The rate of superoxide anion radical generation by submitochondrial particles increased whereas the activities of antioxidative enzymes superoxide dismutase, catalase, and glutathione peroxidase in muscle homogenates remained unaltered with age in the AL group. In calorically-restricted (CR) mice there was no age-associated increase in mitochondrial protein or lipid oxidative damage, or in superoxide anion radical generation. Crossover studies, involving the transfer of 18- to 22-month-old mice fed on the AL regimen to the CR regimen, and vice versa, indicated that the mitochondrial oxidative damage could not be reversed by CR or induced by AL feeding within a time frame of 6 weeks. Results of this study indicate that mitochondria in skeletal muscles accumulate significant amounts of oxidative damage during aging. Although such damage is largely irreversible, it can be prevented by restriction of caloric intake.

One thousand initiated cycles of in vitro fertilization in women > or = 40 years of age

OBJECTIVE

To evaluate the results of IVF in women > or = 40 years of age using their own oocytes.

DESIGN

Retrospective study.

SETTING

Wolfson and Royal Masonic in vitro fertilization units, London, United Kingdom.

PATIENT(S)

A total of 1,087 IVF cycles were started in women > or = 40 years of age.

INTERVENTION(S)

Medical records of patient outcomes were reviewed.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy, miscarriage, and delivery rates.

RESULT(S)

Of the 1,087 cycles started in 471 women > or = 40 years of age, 842 reached oocyte retrieval (77.5%) and 702 had embryos transferred (64.6%). The pregnancy rate (PR) was significantly lower in women > or = 40 years of age than in a control group of women <40 years of age (11.3% versus 28.2%). It decreased sharply in women >42 years of age, and no women >45 years of age had a child. Women > or = 40 years of age were more likely to miscarry (27% versus 12.7%). When only one embryo was available for transfer, the PR was 3.3%. When >2 embryos were available for transfer, the PR was similar whether 2 or 3 embryos were replaced. No triplet pregnancy occurred. Women > or = 40 years of age achieved a cumulative PR of 30% after three cycles with a cumulative "take home baby" rate of 21%.

CONCLUSION(S)

In vitro fertilization is a reasonable treatment for women <45 years of age using their own gametes. Those with a "good response" in their first attempt may be encouraged to complete three cycles with an acceptable chance of conception.

Effect of salpingectomy on ovarian response to superovulation in an in vitro fertilization-embryo transfer program

OBJECTIVE

To investigate the effect of salpingectomy on the response of each ovary in patients undergoing an IVF-ET treatment cycle and to compare the results with those of patients who had not had surgery and were undergoing IVF-ET during the same period.

DESIGN

A prospective study.

SETTING

Tertiary referral academic IVF unit.

PATIENT(S)

Twenty-nine ET cycles were evaluated in 29 patients who previously had undergone unilateral salpingectomy because of ectopic pregnancy (study group). Seventy-three patients with unexplained or male factor infertility served as controls.

INTERVENTION(S)

Ovulation induction and IVF-ET.

MAIN OUTCOME MEASURE(S)

In the study group, mean ovarian volume, number of follicles, and number of oocytes recovered from each ovary were assessed and compared. The overall results, cycle characteristics, and pregnancy rates of the two groups were compared.

RESULT(S)

Among the patients who had undergone salpingectomy, significantly fewer follicles developed and consequently fewer oocytes were retrieved from the ovary on the operated side (4.4 versus 8.2 follicles and 3.8 versus 6.0 oocytes). There were no differences in the total numbers of follicles and oocytes recovered from both ovaries, the cycle characteristics, or the pregnancy rates between study and control groups.

CONCLUSION(S)

Salpingectomy has no detrimental effect on the total ovarian performance during IVF-ET treatment or on the outcome of IVF-ET. However, the ipsilateral ovary could be adversely affected. This could be detrimental in selected patients undergoing IVF-ET, in whom the second ovary already is compromised or missing.

Histological evaluation of endometrium on the day of oocyte retrieval after gonadotrophin-releasing hormone agonist-follicle stimulating hormone ovulation induction for in-vitro fertilization

The objective of this study was to evaluate the histopathological characteristics of endometrial biopsies taken on the day of oocyte recovery in in-vitro fertilization (IVF) cycles with a satisfactory response to ovulation induction. A group of 33 patients who went through ovulation induction for IVF, and in whom an endometrial polyp was suspected on transvaginal ultrasonography during the monitoring phase, were studied. Following oocyte recovery, hysteroscopy, polypectomy and endometrial curettage were performed. Dating of endometrial glands and stroma was carried out in the tissue not containing the polyps. The total dose of follicle stimulating hormone (FSH), duration of ovulation induction, peak oestradiol and luteinizing hormone (LH) concentrations, thickness of endometrium and number of oocytes were recorded and compared to the endometrial dating of the specimens. In 15 cycles (45.5%), the endometrium was classified as 'in phase' (group I), 'advanced' by 2-4 days in a further 15 (45.5%, group II), and in the remaining three cycles (9%) it was delayed in maturation (group III). Younger age was correlated with advanced staging of the endometrium (r = -0.42; P = 0.015). Women with 'in phase' and 'advanced' maturation were similar in their response to ovulation induction; however, there was a strong correlation between advanced dating of endometrium and number of oocytes retrieved (r = 0.49; P = 0.04). Endometrial staging on the day of oocyte retrieval varied widely in patients treated by the same gonadotrophin-releasing hormone agonist (GnRHa)/FSH protocol for ovulation induction. This difference was not predictable by parameters monitored through the cycles.

A programme of semen cryopreservation for patients with malignant disease in a tertiary infertility centre: lessons from 8 years' experience

The improved survival in recent years of young males suffering from cancer, and an understanding of the gonadotoxic effects of chemotherapy treatment, have motivated patients and clinicians to preserve fertility potential before embarking on adjuvant therapy. Among 231 men (mean age 28.0; range 15-56 years) diagnosed with malignant disease and referred to our unit for semen cryopreservation, 112 patients (49.8%) had reduced sperm quality of <10 x 10(6) motile spermatozoa per ejaculate; however, most had sufficient suitable spermatozoa for freezing. In 40 patients (17.3 %) the semen samples were not frozen because of complete azoospermia (n = 32) or only immotile sperm in the ejaculate (n = 2), while six men were unable to produce a single sample. Some 79 men had testicular tumours (group I), 121 suffered from haematological malignancy (leukaemia or lymphoma; group II), and 27 had cancer of different causes (group III). Men in group I had significantly lower (P < 0.001) sperm quality compared with groups II and III. There was no difference between patients with seminoma and non-seminoma tumours. In the haematological malignancy group there was no difference in sperm parameters between leukaemia (n = 12) and lymphoma (n = 77) patients, but patients with Hodgkin's lymphoma had significantly lower sperm quality compared with non-Hodgkin's lymphoma. Following chemotherapy, six couples attended the clinic for assisted conception treatment using the frozen semen. Two had successful intrauterine insemination cycles which each resulted in delivery of a healthy girl; one couple had conceived in their first in-vitro fertilization (IVF) attempt, followed by delivery of healthy twins. Two women conceived after intracytoplasmic sperm injection treatment and the sixth woman achieved only biochemical pregnancy after numerous IVF and frozen embryo replacement cycles. We recommend that a properly designed programme for semen cryopreservation for cancer patients should be developed in leading tertiary assisted conception centres, which have adequate facilities and experience for cryopreservation and can offer the whole range of appropriate assisted reproductive treatment and counselling.

Electron transport-linked ubiquinone-dependent recycling of alpha-tocopherol inhibits autooxidation of mitochondrial membranes

The objective of this study was to elucidate the anti-oxidative roles of coenzyme Q (CoQ) and alpha-tocopherol in mitochondrial membranes by determining whether CoQ directly scavenges peroxyl- and alkoxyl-radicals or indirectly regenerates alpha-tocopherol during autooxidation of mitochondrial membranes. A comparison of the interaction between alpha-tocopherol and CoQ during autooxidation was made between bovine and rat heart mitochondria, which differ approximately 15-fold in their alpha-tocopherol content. Autooxidation of both bovine and rat heart mitochondria resulted in the formation of thiobarbituric-acid-reactive substances and protein carbonyls; however, the differences in the autooxidizability of mitochondria between rat and bovine heart mitochondrial membranes were relatively minor. Supplementation of rat heart mitochondria with succinate caused reduction of CoQ to ubiquinol while alpha-tocopherol concentration remained unaffected during autooxidation. In contrast, in the absence of succinate, CoQ was present in the oxidized form (ubiquinone) and the mitochondrial membranes were depleted of alpha-tocopherol. CoQ concentrations remained unchanged over time irrespective of the presence or absence of succinate. In the absence of succinate, autooxidation of bovine SMPs, supplemented with different amounts of alpha-tocopherol, was inversely related to the amount of alpha-tocopherol, whereas in the presence of succinate autooxidation was greatly reduced. Results of this study indicate that during autooxidation of mitochondria, alpha-tocopherol acts as the direct radical scavenger, whereas ubiquinol regenerates alpha-tocopherol.

Predictive value of the results of a first in-vitro fertilization cycle on the outcome of subsequent cycles

This study examines the relationship between the first cycle of in-vitro fertilization (IVF) and subsequent cycles. The results of all IVF cycles conducted at The Hammersmith Hospital or The Royal Masonic Hospital between 1988 and 1995 were studied including those cycles where egg recovery was abandoned due to poor ovarian response. All patients underwent a standardized treatment protocol. Of those women who achieved a clinical pregnancy during their first IVF attempt, 33% achieved a pregnancy during their second cycle, statistically significantly different from the 24% of patients conceiving during a second cycle who had failed to conceive during their first. 36% of those who achieved a biochemical pregnancy in their first cycle became pregnant in their second. Age was an important factor in the success of IVF treatment, with pregnancy rates of 48% in the 20-25 year age group falling to 8% in those aged > or =41 years. Cumulative pregnancy rates were 26% after one cycle, increasing to 43% after two cycles and reached 80% after seven cycles. A previous pregnancy significantly improved a couple's probability of conception in a later IVF cycle. Overall pregnancy rates per cycle were constant for the first three attempts. Cumulative pregnancy rates continued to rise to 72% after six cycles. Thus the more cycles a couple undergo (up to six) the greater their chance of a pregnancy.

Mitochondrial ubiquinone homologues, superoxide radical generation, and longevity in different mammalian species

Rates of mitochondrial superoxide anion radical (O-2) generation are known to be inversely correlated with the maximum life span potential of different mammalian species. The objective of this study was to understand the possible mechanism(s) underlying such variations in the rate of O-2 generation. The hypothesis that the relative amounts of the ubiquinones or coenzyme Q (CoQ) homologues, CoQ9 and CoQ10, are related with the rate of O-2 generation was tested. A comparison of nine different mammalian species, namely mouse, rat, guinea pig, rabbit, pig, goat, sheep, cow, and horse, which vary from 3.5 to 46 years in their maximum longevity, indicated that the rate of O-2 generation in cardiac submitochondrial particles (SMPs) was directly related to the relative amount of CoQ9 and inversely related to the amount of CoQ10, extractable from their cardiac mitochondria. To directly test the relationship between CoQ homologues and the rate of O-2 generation, rat heart SMPs, naturally containing mainly CoQ9 and cow heart SMPs, with high natural CoQ10 content, were chosen for depletion/reconstitution experiments. Repeated extractions of rat heart SMPs with pentane exponentially depleted both CoQ homologues while the corresponding rates of O-2 generation and oxygen consumption were lowered linearly. Reconstitution of both rat and cow heart SMPs with different amounts of CoQ9 or CoQ10 caused an initial increase in the rates of O-2 generation, followed by a plateau at high concentrations. Within the physiological range of CoQ concentrations, there were no differences in the rates of O-2 generation between SMPs reconstituted with CoQ9 or CoQ10. Only at concentrations that were considerably higher than the physiological level, the SMPs reconstituted with CoQ9 exhibited higher rates of O-2 generation than those obtained with CoQ10. These in vitro findings do not support the hypothesis that differences in the distribution of CoQ homologues are responsible for the variations in the rates of mitochondrial O-2 generation in different mammalian species.

Right or left ovary--which one is better?

This study tests the hypothesis that there is a different response after gonadotrophin-releasing hormone and human menopausal gonadotrophins (GnRH/HMG) stimulation for in-vitro fertilization (IVF) in patients with either a right or left ovary. A total of 56 cycles in 44 women after left oophorectomy (group A) was compared with 42 cycles in 29 women following right oophorectomy (group B). Tubal disease was the sole cause of infertility in all cases. The two groups were similar in age. There was no difference in total amount or days of HMG required for ovulation induction, peak oestradiol concentrations, number of oocytes retrieved and fertilization rate. The pregnancy rate was identical in the two groups (20.0 and 20.9% respectively). Our results indicate that with GnRH/HMG ovulation induction protocol for IVF there is no predilection of one ovary over the other.