Concentration of soluble urokinase plasminogen activator receptor (suPAR) in the pre-ovulatory follicular fluid is associated with development of ovarian hyperstimulation syndrome during ovarian stimulation

PURPOSE

Investigating whether pre-ovulatory follicular fluid (FF) levels of selected proteins differ between women who do or do not develop severe ovarian hyperstimulation syndrome (OHSS) and evaluate whether they potentially could guide a "freeze-all" strategy.

METHODS

FF was collected during a randomized controlled trial comparing OHSS in antagonist versus agonist protocol including 1050 women in their first assisted reproductive technology (ART) cycle during year 2009-2013. The present sub-study is a matched case-control study comparing FF levels of soluble urokinase plasminogen activator receptor (suPAR), C-reactive protein, placental growth factor, vascular endothelial growth factor, and angiopoietins 1 and 2 in OHSS cases (n = 25, severe OHSS, and ≥ 15 oocytes), high-risk controls (n = 25, no OHSS, and ≥ 15 oocytes), and low-risk controls (n = 25, no OHSS, and 5-8 oocytes).

RESULTS

FF level of suPAR differed significantly between the three groups (p = 0.018) with mean (SD) levels of 2.3 (0.4) μg/L, 2.6 (0.8) μg/L, and 2.8 (0.6) μg/L in OHSS cases, high-risk controls, and low-risk controls, respectively. Receiver operating characteristic curve analysis demonstrated that suPAR levels could predict severe OHSS (AUC 0.678; 95% CI 0.553-0.803) with a sensitivity of 64% and a specificity of 66%. None of the other investigated proteins differed between the three groups or between OHSS cases and combined controls.

CONCLUSION

The pre-ovulatory FF level of suPAR was significantly lower in women developing severe OHSS, indicating that the plasminogen activator system could be involved in the pathophysiology of OHSS. However, suPAR did not provide a satisfying predictive value for the prediction of OHSS.

Paraoxonase activities in human follicular fluid: role in follicular maturation

The paraoxonases (PONs) are antioxidant enzymes associated with beneficial effects against several diseases and some exposures. Little is known, however, about the role of PONs in human reproduction. This work was conducted to investigate whether any association existed between the activities of the PON enzymes (1, 2, and 3) with the follicular size and fertility parameters in assisted reproduction. The study included 100 subfertile women (patients) and 55 proven fertile women (oocyte donors), all undergoing an ovarian stimulation cycle. Follicular fluid from small (diameter <12 mm) and large (diameter ≥18 mm) follicles was collected from each woman. The PONs were quantified in follicular fluid by immunoblotting. PON1 arylesterase and paraoxonase, PON2 methyl paraoxonase and PON3 simvastatinase activities from both donors and patients were significantly higher (P < 0.001) in follicular fluid from large follicles compared with small ones. In large follicles, PON3 activity was significantly higher (P < 0.01) in donors compared with patients. Follicular fluid PON1 arylesterase and paraoxonase activity was positively correlated with the number of retrieved oocytes in donors. This study shows an increase in the activities of PONs with follicle size, thus providing indirect evidence for the role of PONs in follicle maturation.

Pro-nerve growth factor in the ovary and human granulosa cells

BACKGROUND

Pro-nerve growth factor must be cleaved to generate mature NGF, which was suggested to be a factor involved in ovarian physiology and pathology. Extracellular proNGF can induce cell death in many tissues. Whether extracellular proNGF exists in the ovary and may play a role in the death of follicular cells or atresia was unknown.

MATERIALS AND METHODS

Immunohistochemistry of human and rhesus monkey ovarian sections was performed. IVF-derived follicular fluid and human granulosa cells were studied by RT-PCR, qPCR, Western blotting, ATP- and caspase-assays.

RESULTS AND CONCLUSION

Immunohistochemistry of ovarian sections identified proNGF in granulosa cells and Western blotting of human isolated granulosa cells confirmed the presence of proNGF. Ovarian granulosa cells thus produce proNGF. Recombinant human proNGF even at high concentrations did not affect the levels of ATP or the activity of caspase 3/7, indicating that in granulosa cells proNGF does not induce death. In contrast, mature NGF, which was detected previously in follicular fluid, may be a trophic molecule for granulosa cells with unexpected functions. We found that in contrast to proNGF, NGF increased the levels of the transcription factor early growth response 1 and of the enzyme choline acetyl-transferase. A mechanism for the generation of mature NGF from proNGF in the follicular fluid may be extracellular enzymatic cleavage. The enzyme MMP7 is known to cleave proNGF and was identified in follicular fluid and as a product of granulosa cells. Thus the generation of NGF in the ovarian follicle may depend on MMP7.

Matrix metalloproteinase 2 level in human follicular fluid is a reliable marker of human oocyte maturation in in vitro fertilization and intracytoplasmic sperm injection cycles

BACKGROUND

To determine whether matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMP-1 and TIMP-2) in human follicular fluid, have any relationships with oocyte maturation in vivo and subsequent fertilization during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles.

METHODS

The follicular fluids were obtained from 150 female patients undergoing IVF/ICSI cycles and a total of 1504 oocytes were retrieved for analysis. MMP-2 and MMP-9 activities were measured using zymography assay. TIMP-1 and TIMP-2 concentrations were quantitatively assessed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Human follicular fluid MMP-2 level was significantly associated with the rate of maturity of oocytes (P < 0.001). Furthermore, the MMP-2 was significantly associated with the higher fertilization rate (P < 0.01). There was no significant correlation between follicular MMP-9 and the maturation rate of oocytes. The TIMP-1 and TIMP-2 also showed no correlation with the oocyte maturation rate.

CONCLUSIONS

The level of gelatinase MMP-2 in human follicular fluid might be a reliable marker of mature oocytes during IVF/ICSI cycles. Furthermore, the MMP-2 expression has a strong association with higher fertilization rate. Further studies are needed to support this theory.

Arachidonic and linoleic acid derivatives impact oocyte ICSI fertilization--a prospective analysis of follicular fluid and a matched oocyte in a 'one follicle--one retrieved oocyte--one resulting embryo' investigational setting

Objective

To evaluate human oocyte ability to undergo fertilization and subsequent preimplantation embryonic development in relation to a wide panel of follicular fluid (FF) arachidonic acid derivatives (AAD) and linoleic acid derivatives (LAD) of prospectively selected patients undergoing intracytoplasmic sperm injection (ICSI).

Methodology

Study was designed as a two center (a university clinic and a private clinic) prospective study. 54 women of 181 consecutive couples undergoing ICSI were prospectively found to be eligible for analysis. 'One follicle – one retrieved oocyte – one resulting embryo' approach was used. Each individual follicle was aspirated independently and matched to an oocyte growing in this particular follicular milieu. FF samples were assessed for AAD and LAD by high-performance liquid chromatography; additionally, activity of secretory phospholipase A (sPLA₂) was determined by enzyme-linked immunosorbent assay.

Principal Findings

Increased activity of sPLA₂ and significantly higher AAD and LAD levels were found in FF of oocytes that did not show two pronuclei or underwent degeneration after ICSI in comparison to oocytes with the appearance of two pronuclei. Receiver operating characteristics curve analysis identified acids with the highest sensitivity and specificity: 5oxo-hydroxyeicosatetraenoic, 16-hydroxyeicosatetraenoic, 9-hydroxyoctadecadieneoic and 12-hydroxyeicosatetraenoic. No significant differences between AAD and LAD related to embryo quality were found.

Conclusions/Significance

Our study demonstrates for the first time that elevated concentrations of AAD and LAD in FF at the time of oocyte retrieval significantly decrease the ability of oocytes to form pronuclei after ICSI. This may serve as a new tool for non-invasive assessment of oocyte developmental capacity. However, levels of AAD and LAD are not associated with subsequent embryo quality or pregnancy rate, and therefore more studies are needed to determine their usefulness in human IVF procedure.

Do alterations in follicular fluid proteases contribute to human infertility?

PURPOSE

Cathepsin L and ADAMTS-1 are known to play critical roles in follicular rupture, ovulation, and fertility in mice. Similar studies in humans are limited; however, both are known to increase during the periovulatory period. No studies have examined either protease in the follicular fluid of women with unexplained infertility or infertility related to advanced maternal age (AMA). We sought to determine if alterations in cathepsin L and/or ADAMTS-1 existed in these infertile populations.

METHODS

Patients undergoing in vitro fertilization (IVF) for unexplained infertility or AMA-related infertility were prospectively recruited for the study; patients with tubal or male factor infertility were recruited as controls. Follicular fluid was collected to determine gene expression (via quantitative polymerase chain reaction), enzyme concentrations (via enzyme-linked immunosorbent assays), and enzymatic activities (via fluorogenic enzyme cleavage assay or Western blot analysis) of cathepsin L and ADAMTS-1.

RESULTS

The analysis included a total of 42 patients (14 per group). We found no statistically significant difference in gene expression, enzyme concentration, or enzymatic activity of cathepsin L or ADAMTS-1 in unexplained infertility or AMA-related infertility as compared to controls. We also found no statistically significant difference in expression or concentration with advancing age.

CONCLUSIONS

Cathepsin L and ADAMTS-1 are not altered in women with unexplained infertility or AMA-related infertility undergoing IVF, and they do not decline with advancing age. It is possible that differences exist in natural cycles, contributing to infertility; however, our findings do not support a role for protease alterations as a common cause of infertility.

Evidence that increased ovarian aromatase activity and expression account for higher estradiol levels in African American compared with Caucasian women

CONTEXT

Serum estradiol levels are significantly higher across the menstrual cycle in African American (AAW) compared with Caucasian women (CW) in the presence of similar FSH levels, yet the mechanism underlying this disparity is unknown.

OBJECTIVE

The objective of the study was to determine whether higher estradiol levels in AAW are due to increased granulosa cell aromatase mRNA expression and activity.

DESIGN

The design of the study included daily blood sampling and dominant follicle aspirations at an academic medical center during a natural menstrual cycle.

SUBJECTS

Healthy, normal cycling AAW (n = 15) and CW (n = 14) aged 19-34 years participated in the study.

MAIN OUTCOME MEASURES

Hormone levels in peripheral blood and follicular fluid (FF) aspirates and aromatase and FSH receptor mRNA expression in granulosa cells were measured.

RESULTS

AAW had higher FF estradiol [1713.0 (1144.5-2032.5) vs 994.5 (647.3-1426.5) ng/mL; median (interquartile range); P < .001] and estrone [76.9 (36.6-173.4) vs 28.8 (22.5-42.1) ng/mL; P < .001] levels than CW, independent of follicle size. AAW also had lower FF androstenedione to estrone (7 ± 1.8 vs 15.8 ± 4.1; mean ± SE; P = .04) and T to estradiol (0.01 ± 0.002 vs 0.02 ± 0.005; P = .03) ratios, indicating enhanced ovarian aromatase activity. There was a 5-fold increase in granulosa cell aromatase mRNA expression in AAW compared with CW (P < .001) with no difference in expression of FSH receptor. FSH, inhibin A, inhibin B, and AMH levels were not different in AAW and CW.

CONCLUSIONS

Increased ovarian aromatase mRNA expression, higher FF estradiol levels, and decreased FF androgen to estrogen ratios in AAW compared with CW provide compelling evidence that racial differences in ovarian aromatase activity contribute to higher levels of estradiol in AAW across the menstrual cycle. The absence of differences in FSH, FSH receptor expression, and AMH suggest that population-specific genetic variation in CYP19, the gene encoding aromatase, or in factors affecting its expression should be sought.

Immunohistochemical expression of MMP-14 and MMP-2, and MMP-2 activity during human ovarian follicular development

BACKGROUND

The aim of this study was to investigate the presence of MMP-14 and MMP-2 during human ovarian follicular development using immunohistochemistry, and the activity of MMP-2 in follicular fluid using zymography.

METHODS

Ovarian tissue collected from the archives of the Department of Pathology was examined and medical records and histopathology were reviewed. Follicular fluids were collected at the IVF-department and analyzed using zymography.

RESULTS

MMP-14 and MMP-2 were increasingly found in the growing follicles and MMP-2 was highly expressed in the corpus luteum. Pro-MMP-2 was present in follicular fluid of IVF-patients.

CONCLUSIONS

The presence of MMP-14 and MMP-2 during human ovarian follicular development from the primordial follicle to the tertiary follicle and corpus luteum is confirmed, as was indicated by earlier animal studies following stimulation with gonadotrophins.

Gelatinases (MMP2 and MMP9) in swine antral follicle

Follicular growth is allowed by extracellular matrix remodeling and vascular network development. Since matrix metalloproteinases (MMPs) play a crucial role in both of these processes, the aim of the present study was to evaluate the expression of gelatinases MMP2 and MMP9 in swine ovarian follicle (theca and granulosa compartments) during its development. Moreover, we measured gelatinase activities into follicular fluids (FF). Our data demonstrate for the first time that MMP2 and MMP9 are expressed in swine ovarian follicle both in theca and granulosa layers; moreover we show that the expression of both gelatinases increases in theca while decreases in granulosa during follicle growth. Additionally, MMP2 activity has been detected in FF. The spatial pattern of expression of gelatinases in swine follicle suggests a differential role during physiological ovarian events.

Intrafollicular levels of matrix metalloproteinases-2 and -9 in patients with polycystic ovaries are not associated with pregnancy rate during IVF cycle

This study aimed to detect the levels of matrix metalloproteinases (MMP)-2 and -9, using enzyme-linked immunosorbent assays, in the follicular fluid of 35 patients with polycystic ovaries, compare them with the levels found in 35 normally ovulating women enrolled in their first in vitro fertilization (IVF) cycle and then correlate them with pregnancy rates in these two groups. Levels of MMP-9 were found significantly increased in women with polycystic ovaries when compared with the controls, while MMP-2 levels were higher in women with polycystic ovaries without reaching statistical significance. The two groups did not differ in age, in the number of embryos transferred or in pregnancy rates. In conclusion, the results indicated an increased gelatinolytic activity in patients with polycystic ovaries after ovarian stimulation for IVF treatment without detecting any association between levels of MMP-2 and 9 and IVF pregnancy rates.

Selective processing of a follicular matrix metalloproteinase-2 isoform by human oviducal fluid

The present study demonstrates that a unique isoform of matrix metalloproteinase (MMP)-2 present in human follicular fluid (FF) can be processed selectively by human oviducal fluid (OF). A gelatin zymogram of untreated FF showed distinct 88-, 84- and 62-kDa gelatinases. Treatment of FF with EDTA resulted in the appearance of 110-kDa gelatinase (GA110). Most gelatinases, except for the 88- and 84-kDa gelatinases, were abolished by pretreatment with EDTA or phenanthroline, but not by pretreatment with a serine/threonine protease inhibitor. When EDTA-pretreated FF was mixed with OF, the GA110 of the FF was specifically reduced. The reduction in GA110 was dependent upon the amount of OF protein and the incubation period after mixing. Treatment of FF with aminophenylmercuric acetate reduced GA110 activity, but this reduction was accompanied by a concomitant increase of 62-kDa gelatinase activity. Anti-human MMP-2 antibody strongly reacted with both GA110 and 62-kDa gelatinases of FF, but only GA110 immunoreactivity was abolished when FF was mixed with OF. The results suggest that the GA110 of FF is an MMP-2 isoform that can be processed selectively by OF.

Granulosa cell aromatase enzyme activity: effects of follicular fluid from patients with polycystic ovary syndrome, using aromatase conversion and [11C]vorozole-binding assays

The local regulation of ovarian aromatase enzyme in polycystic ovary syndrome (PCOS) was studied with aromatase conversion and [11C]vorozole-binding assays to analyze aromatase activity, substrate-enzyme affinity and number of aromatase binding sites in non-cultured human granulosa cells (GC) incubated with different sources and preparations of follicular fluid (FF). Incubation with FF from women stimulated in in vitro fertilization cycles with follicle-stimulating hormone yielded higher conversion activity than with FF from healthy women and PCOS patients, paralleled with higher substrate affinity (lower Kd) than with FF from healthy women. In PCOS women, charcoal-pretreated FF yielded higher conversion, whereas the ether-pretreated FF yielded lower conversion activity, than with untreated PCOS FF. Both preparations of FF yielded higher affinity to substrate (lower Kd values) and the ether-pretreated FF a lower number of binding sites (Bmax). It seems that steroids with the presence of proteins in PCOS FF reduced aromatase conversion activity through decreased substrate affinity, whereas FF preparations devoid of proteins reduced the aromatase conversion activity mainly through blocking of aromatase active sites. Identification of specific agents responsible for this rapid regulation of aromatase function might help to understand normal regulation of the menstrual cycle and supposed imbalances of inhibitors/activators in PCOS.

Ovarian iodide uptake and triiodothyronine generation in follicular fluid. The enigma of the thyroid ovary interaction

Since 1928, the iodine concentration in the ovary has been known to be higher than in every other organs except the thyroid. The ovarian iodide uptake varies with sexual activities, is enhanced by estrogens and a hypothyroid state and blocked by goitrogens. The recent discovery of a sodium iodide symporter (NIS) in ovaries has offered a possible mechanism for ovarian iodide uptake and other functional similarities to its thyroid counterpart. Nevertheless, the physiological significance of ovarian iodine uptake and accumulation remains unknown. The presence of thyroid hormones (TH) in follicular fluid (FF) has been established recently. Our preliminary studies on TH in FF (1996-1998) in rabbits, pigs, horses showed that the concentration of T4 is generally lower than that in serum and that for T3 is within the normal range or higher. A positive correlation exists between the T4 levels in FF and serum but not between the corresponding T3 levels. These studies revealed, for the first time, the presence of the ovarian 5'-monodeiodinase system in FF capable of generating T3 (ovary-born T3) by outer ring deiodination of T4. In mares, seasonal polyestrus, ovarian 5'-monodeiodinase (MD) activity and FF T3 levels have been found to be higher during the ovulatory period than in the anovulatory one. The exact physiological significance of this system generating T3 and coexisting with isoforms of TH receptors in granulosa cells has not been elucidated. A direct role of T3 for the early follicular development, differentiation and for the steroidogenic capability of granulosa cells, although strongly suggested by data obtained from in vitro studies, has to be elucidated.

[Intrafollicular levels of sexual steroids and their relation with the antioxidant enzymes on the oocyte quality in an in vitro fertilization program]

OBJECTIVE

To establish a correlation between intrafollicular superoxide dismutase enzyme concentrations, activity with oestradiol levels, and the effects on oocyte quality and maturity.

STUDY

Prospective, descriptive and observational.

MATERIAL AND METHODS

Forty-one patients underwent IVF-ET program. The ovarian stimulation protocol was made with recombinant FSH and GnRH antagonists. All follicles were aspirated one by one, and the follicular fluid was stored at a -20 degrees C room temperature. We retrieved 120 follicular fluids and performed the measurement of oestradiol and superoxide dismutase enzyme on each follicular fluid and its correlation with fertilization and cleavage rates. Statistical analysis was carried out with ANOVA, t Student, chi2 and P Pearson tests.

RESULTS

Patients' mean age was of 33.74 +/- 5.04 years, the mean of enzyme activity was of 76.89%, and the mean concentration of superoxide dismutase enzyme was of 68.71 UI/L. According to oocyte quality or maturity, no statistical differences were observed when comparing oestradiol levels with superoxide dismutase enzyme concentrations. But when we analized both variables, we observed a positive correlation in metaphase 2 oocytes (p = 0.236). When we correlated the superoxide dismutase enzyme activity with oestradiol concentrations in relation to oocyte quality, a positive correlation in good quality oocytes was observed too (p = 0.218). We perceived a strong correlation between SOD concentrations and oestradiol intrafollicular measurements in good quality oocytes.

COMMENTS

Oocyte maturity and development are conditionated by a close relationship between SOD and intrafollicular oestradiol.

Production of matrix metalloproteinases by cultured bovine theca and granulosa cells

Matrix metalloproteinases (MMPs) degrade the proteinaceous components of the extracellular matrix and are presumably essential for follicular growth culminating in ovulation or atresia. The objectives of this study were to characterize the gelatinolytic and caseinolytic MMPs secreted by cultured bovine thecal and granulosal cells and to determine the effect of luteinizing hormone (LH) on MMP secretion. Thecal and granulosal cells were collected from small bovine follicles (<5 mm) on day 2 or 5 of the estrous cycle (day 0 = estrus). A serum-free culture system was utilized in which bovine thecal and granulosal cells do not spontaneously luteinize, but produce androstenedione and estradiol in response to physiological concentrations of LH and follicle-stimulating hormone (FSH) respectively. The effect of LH (0, 1 or 100 ng/ml) on MMP production was determined in conditioned media collected every 48 h for 144 h. MMPs were detected by gelatin and casein zymography and MMP activity was quantified by image analysis. Thecal and granulosal cell conditioned media contained MMPs that had a relative molecular size (Mr) ranging from 53 000 to 200 000 and addition of 1,10 phenanthroline (MMP inhibitor) blocked gelatinolytic and caseinolytic activity. Patterns of gelatinolytic activity in thecal and granulosal cell conditioned media differed over time with theMr62 000 and 83 000 MMPs being increased (P< 0.05) and theMr53 000 MMP being decreased (P< 0.05) at 96 h of culture. LH (1 or 100 ng/ml) increased (P< 0.05) gelatinolytic activity of theMr53 000 and 62 000 gelatinases within thecal cell conditioned media but not granulosal cell conditioned media. TheMr62 000 and 83 000 gelatinolytic activities corresponded to the active forms of gelatinase A (Mr62 000) and B (Mr, 83 000) and gelatinase A was detected in thecal cell conditioned media by Western blot analysis. Caseinolytic activity (Mr83 000) was detected in both thecal and granulosal cell conditioned media and increased from 48 to 96 h. In summary, thecal and granulosal cells secrete gelatinolytic and caseinolytic MMPs and thecal cell production of gelatinase A was stimulated by LH.

Activity of an enzyme converting single-chain tissue-type plasminogen activator to the two-chain form in preovulatory human follicular fluid

The biological role of the tissue-type plasminogen activator (tPA)/plasmin system has long been implicated in ovarian function. We have recently shown that the follicular fluid of human ovaries contains an alpha(2)-macroglobulin/protease complex capable of converting single-chain (sc) tPA to the two-chain (tc) enzyme tPA, suggesting the occurrence of its corresponding enzyme in a free form in the fluid. The aim of the current study is therefore to gain further information about the putative sctPA-converting enzyme present in follicular fluid. Incubation of human recombinant sctPA with the fluid brought about the production of tctPA. It was also demonstrated that tctPA production resulted in the activation of endogenous fluid plasminogen. Production of tctPA and plasmin both was strongly inhibited by aprotinin, suggesting that the enzyme is a serine protease. The sctPA-converting enzyme was partially purified from the fluid by column chromatographies. The enzyme preferably hydrolyzed synthetic peptide substrates containing arginine at the P(1) position. The enzyme preparation had a protease inhibitor profile similar to that observed with the crude fluid sample. These results clearly demonstrated that follicular fluid contains an enzyme capable of efficiently converting sctPA to tctPA. Discovery of this sctPA-converting enzyme strongly suggests that the tPA/plasmin system in the preovulatory follicle of human ovaries is operated through the proteolytic conversion of sctPA to tctPA rather than being regulated by a fibrin-dependent mechanism.

Antioxidant enzymatic defences in human follicular fluid: characterization and age-dependent changes

The aim of this work was to study the antioxidant enzymatic defences in human follicular fluid and investigate their possible changes during reproductive ageing. To this end, we tested the specific activities and protein expression of enzymes involved in reactive oxygen species (ROS) scavenging and in detoxification of ROS byproducts in follicular fluid from young (range 27-32 years, n = 12) and older (range 39-45 years, n = 12) women participating in an IVF programme. Results show that all the tested enzymes [superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione transferase, glutathione reductase] were significantly expressed in human follicular fluid. However, when the two age groups were compared, we found that follicular fluid from older women exhibited a reduced level of glutathione transferase and catalase activities and a higher level of SOD activity. Immunoblot analysis revealed that ageing was associated with decreased protein expression of GST Pi isoform and did not affect SOD and catalase protein expression. Taken together, these findings indicate that reproductive ageing is accompanied by a change in the antioxidant enzymatic pattern that could impair ROS scavenging efficiency in the follicular environment.

Protection of porcine oocytes against cell damage caused by oxidative stress during in vitro maturation: role of superoxide dismutase activity in porcine follicular fluid

To elucidate the beneficial effects of porcine follicular fluid (pFF) added to maturation medium on the sustenance of cytoplasmic maturation responsible for the subsequent developmental competence after in vitro fertilization (IVF) of porcine oocytes, we focused on the antioxidative role of pFF in its function of protecting oocytes from reactive oxygen species (ROS)-induced cell damage. Porcine follicular fluid collected from small (2-6 mm) follicles had about 7.2-fold higher levels of superoxide dismutase (SOD) activity than that of fetal bovine serum (FBS), and this activity was markedly blocked by the CuZn-SOD inhibitor, diethyldithiocarbamate (DETC). The interruption of meiotic progression and the increasing intracellular glutathione (GSH) content throughout the maturation period, as well as an outbreak of DNA damage in oocytes and cumulus cells were difficult to detect in oocytes cultured in a medium supplemented with 10% pFF, even in the presence of ROS generated by the hypoxanthine-xanthine oxidase system, whereas cell damage encompassed by ROS was prominent in oocytes cultured with 10% FBS and 10% pFF plus 100 microM DETC. Similarly, significant enhancement to the degree of transformation of the sperm nucleus into the male pronucleus (MPN) after in vitro fertilization was shown by the addition of pFF to the maturation medium. The presence of DETC during in vitro maturation reduced the ability of oocytes to promote MPN formation to the same extent as oocytes matured with FBS. The proportion developing to the blastocyst stage was increased in oocytes that matured with pFF, but this developmental competence was significantly lowered by treatment with DETC (P < 0.05). These findings suggest that pFF plays a critical role in protecting oocytes from oxidative stress through a higher level of radical scavenging activity elicited from SOD isoenzymes, resulting in the enhancement of cytoplasmic maturation responsible for developmental competence postfertilization.

Matrix metalloproteinase-2 and -9 secretion by the equine ovary during follicular growth and prior to ovulation

Profound hormonally controlled tissue remodelling occurs in the equine ovary for follicle growth and development, and also for the alteration in follicle shape directed towards the ovulation fossa, the site where ovulation occurs. The aim of this study was to examine the spatial and temporal regulation of matrix metalloproteinases (MMP)-2 and MMP-9, important enzymes in tissue remodelling, during follicle growth, and ovulation. Using gelatin substrate zymography, we measured these MMPs in follicular fluid of large anovulatory follicles collected during spring transition, early dominant follicles (> 23 mm), and at oestrus in follicles approximately 3 days prior to ovulation, and post-hCG treatment when ovulation was predicted in approximately 4 h. The most abundant activity detected in follicular fluid was MMP-2, although there were no changes in secretion or activation in association with ovulation. The activity of MMP-9 was detected in lower amounts, with no changes prior to ovulation, although it decreased significantly (P < 0.05) post-hCG treatment. At oestrus, when different regions of the ovary were maintained in explant culture for 24 h, there were no significant changes in either MMP-2 or MMP-9 secretion by stromal tissues collected at the ovarian fossa, adjacent to the preovulatory follicle but away from the fossa, and a further site remote from the preovulatory follicle. Over this same time period, follicular progesterone (P < 0.01) and oestradiol (P < 0.05) increased significantly, although oestradiol tended to decrease after hCG administration. These findings indicate that MMP-2 and MMP-9 are not key acute regulators for the changes in follicle shape immediately prior to ovulation.

Mast cell-sperm interaction: evidence for tryptase and proteinase-activated receptors in the regulation of sperm motility

BACKGROUND

The detection of significant levels of tryptase in human seminal plasma and follicular fluid and of tryptase-positive mast cells (MCs) in the wall of human Fallopian tubes lead us to hypothesize that tryptase may exert regulatory actions on human spermatozoa.

METHODS AND RESULTS

Immunoelectronmicroscopy revealed proteinase-activated receptor 2 (PAR-2) in the membranes of the acrosomal region and midpiece of human spermatozoa. These PAR-2 were functional, as exposure of spermatozoa from healthy men (n = 12) with regular standard semen parameters to human recombinant tryptase significantly decreased motility in a dose- and time-dependent fashion. Motile spermatozoa (WHO a + b) were significantly decreased within 10 min of incubation with 1.000 ng/ml tryptase (P = 0.045). After 30 and 60 min, significant reduction of motility was also observed in the presence of lower tryptase concentrations (100 ng/ml, P = 0.037; 10 ng/ml, P = 0.046). The inhibitory effects of tryptase progressed throughout an observation period of 180 min. Furthermore, tryptase effects were reversible after washing procedures and could be inhibited by pretreatment with anti-tryptase antibody or anti-PAR-2 antiserum.

CONCLUSIONS

The observations presented raise the possibility that tryptase directly interacts with human spermatozoa during their migration through the female genital tract. Genital tract MCs and their products may be as yet unrecognized factors involved in human fertility/sterility.

Antimicrobial activity of human follicular fluids

The aim of this study was to explore the antimicrobial activity of human follicular fluid (HFF), to test the hypothesis that different strains of the same bacterial species could display different patterns of susceptibility to antimicrobial action of HFF, and to preliminarily investigate the possible mechanism of antimicrobial action of this fluid. Antimicrobial activity of 60 samples of HFF toward 30 Streptococcus agalactiae strains was determined by the agar diffusion method and broth dilution method. To explore the mechanism of antimicrobial activity, biochemical analyses were performed with selected fluid samples. The obtained results indicate that 38.3% fluid samples did not inhibit bacterial growth, 53.3% showed moderate and 8.3% high antimicrobial activity. The tested effect of HFF on S. agalactiae strains was bactericidal and was not strain dependent. Lysozyme activity was detected in HFF exhibiting antimicrobial activity. There were no statistically significant differences in concentrations of estradiol, progesterone, transferrin, iron, total protein and albumin levels among tested samples regardless of the different rate of antimicrobial activity. The obtained results indicate that lysozyme is most probably a crucial antibacterial agent in this fluid; however, some other still unidentified factors may contribute to it.

Ovarian modulators of 11beta-hydroxysteroid dehydrogenase (11beta HSD) activity in follicular fluid from bovine and porcine large antral follicles and spontaneous ovarian cysts

In the ovary, cortisol is oxidized to cortisone by 11beta-hydroxysteroid dehydrogenase (11betaHSD). The present study investigated whether follicular fluid (FF) from large antral follicles and spontaneous ovarian cysts, isolated from bovine and porcine ovaries, contained modulators of 11betaHSD activity. Whereas FF from antral follicles had no significant effect over 1 h on NADP+-dependent 11betaHSD activity in rat kidney homogenates, enzyme activity was inhibited by FF from bovine and porcine ovarian cysts (80.5% +/- 2.3% and 72.8% +/- 3.4% of control, respectively). Following C18 reverse-phase chromatography, the hydrophilic fractions of FF from bovine and porcine antral follicles stimulated NADP+-dependent 11betaHSD activities (111.5% +/- 21.6% and 55.2% +/- 5.7% respectively). Hydrophobic compounds inhibited NADP+-dependent cortisol oxidation by 58.2% +/- 5.1% (bovine) and 45.7% +/- 2.0% (porcine). In both species, FF from ovarian cysts appeared to contain less of the hydrophilic stimuli to 11betaHSD activity and more of the hydrophobic inhibitors. The FF from antral follicles and ovarian cysts, and the C18 fractions thereof, had no significant effect on NAD+-dependent cortisol oxidation. The ovarian modulators of NADP+-dependent 11betaHSD activities did not coelute with cortisol, cortisone, estradiol, testosterone, progesterone, pregnenolone, and cholesterol. However, the 11betaHSD stimuli in porcine FF from both antral follicles and cysts coeluted with prostaglandin (PG) E2 and PGF2alpha. We conclude that large antral follicles and spontaneous ovarian cysts, in both the cow and the pig, contain ovarian modulators of the NADP+-dependent 11betaHSD activity. Moreover, FF from spontaneous ovarian cysts, because of decreased content of the 11betaHSD stimulus accompanied by increased content of the 11betaHSD inhibitors, exerts a net inhibitory effect on 11betaHSD activity.

Matrix metalloproteinases-2 and -9 activities in bovine follicular fluid of different-sized follicles: relationship to intra-follicular inhibin and steroid concentrations

Matrix metalloproteinases (MMPs) play very important roles in extracellular matrix (ECM) remodeling during ovarian follicular development, ovulation and atresia. The aim of the present study was to determine the content of gelatinases in follicular fluid in various sized bovine follicles. Bovine ovaries were collected from local slaughterhouse and follicular fluid from follicles of 2 to over 25 mm in diameter was collected. Gelatinase activity within the follicular fluid was analyzed by gelatin zymography. The concentration of inhibin in the follicular fluid was also measured by immunoblot analysis. The proMMP-2 and alpha-subunit (alphaN) inhibin was detected in all follicles regardless of their size. The abundance of proMMP-2 varied with follicular size, while alphaN inhibin increased significantly (P<0.01) in follicles of 10-14 and 15-20 mm in size. There was a positive and negative correlation between estradiol (E(2)) and progesterone (P(4)) concentrations with abundance of proMMP-2, respectively. Follicles of diameter over 25 mm had greater proMMP-9 activity than other follicles. These same follicles had significantly (P<0.01) lower inhibin levels than follicles of 10-14 and 15-20 mm in size. In conclusion, these results suggest a significant role of these proteases in growth and development of bovine follicle, particularly proMMP-2 and active MMP-2 activities in the follicular fluid could serve as markers of follicular health while abundance of proMMP-9 may possibly denote a follicular cyst.

Matrix metalloproteinases 2 and 9 in follicular fluids of patients undergoing controlled ovarian stimulation for ICSI/ET

The objective of this study was to detect the level of matrix metalloproteinases 2 and 9 in the follicular fluid of patients undergoing controlled ovarian stimulation and to correlate these levels with hormonal and clinical parameters. Follicular fluids were collected from thirty patients participating in an intracytoplasmic sperm injection/embryo transfer (ICSI/ET) program in "Otmar Bauer" Assisted Reproduction Center, Alexandroupolis, Greece. Follicular fluid was collected at oocyte retrieval and MMP-2 and MMP-9 were identified by gelatin zymography. Gelatin zymography of the follicular fluids revealed bands consistent with proMMP-2 and proMMP-9. ProMMP-2 was the predominant band in the majority of samples. The levels of MMPs varied considerably among the samples. A significant positive correlation between MMP-2 and the peak estradiol levels was found.

Decreased expression of tissue inhibitor of matrix metalloproteinases in follicular fluid from women with polycystic ovaries compared with normally ovulating patients undergoing in vitro fertilization

OBJECTIVE

To compare activity of matrix metalloproteinases (MMP) and expression of their tissue-specific inhibitor (TIMP) in the follicular fluid of normally ovulating women and women with the polycystic ovary syndrome (PCOS).

DESIGN

Prospective study.

SETTING

IVF unit and endocrine research unit.

PATIENT(S)

Fourteen patients undergoing IVF treatment (seven with normal ovulation and seven with PCOS).

MAIN OUTCOME MEASURE(S)

Activity of MMP-2 and MMP-9 and expression of MMP-1, TIMP-1, and TIMP-2 was measured in follicular fluid of the leading follicles by using gel zymography and immunoblot analysis.

RESULT(S)

The activity of MMP-2 and MMP-9 and expression of MMP-1 was similar in follicular fluid of normally ovulating patients and patients with PCOS. Significantly lower expression of TIMP-1 was found in follicular fluid of patients with PCOS women compared with normally ovulating patients.

CONCLUSION(S)

Because MMPs and TIMPs play a role in the physical and chemical structure of the follicular compartment, the decreased expression of TIMP in patients with PCOS may be part of a compensatory process to overcome the physical properties of the thick ovarian capsule.

Ovarian modulators of 11beta-hydroxysteroid dehydrogenase (11betaHSD) activity in follicular fluid from gonadotrophin-stimulated assisted conception cycles

In the ovary, cortisol-cortisone interconversion is catalysed by isoforms of 11beta-hydroxysteroid dehydrogenase (11betaHSD). The objective of this study was to establish whether human follicular fluid (hFF), obtained after controlled ovarian hyperstimulation, contains paracrine modulators of 11betaHSD activity. Of 274 hFF samples tested for effects in rat kidney homogenates, 206 hFF samples significantly inhibited NADP(+)-dependent oxidation of cortisol within 1 h (by 11-67% of control 11betaHSD activity), whereas 42 hFF samples significantly stimulated 11betaHSD activity (16-210% increase relative to control). Although charcoal-stripping of hFF prevented the inhibition and potentiated the stimulation of NADP(+)-dependent cortisol oxidation in a renal homogenate, effects of individual hFF samples on NADP(+)-dependent cortisol oxidation were independent of intrafollicular progesterone concentrations. Hydrophilic fractions of hFF samples, isolated by C18 column chromatography, stimulated both the NADP(+)-dependent oxidation of cortisol (by 55+/-5%, n=98) and the NADPH-dependent reduction of cortisone (by 86+/-22%, n= 5). In contrast, the hydrophobic fractions of hFF (eluted at 65-85% methanol) inhibited both NADP(+)-dependent 11beta-dehydrogenase and NADPH-dependent 11-ketosteroid reductase activities (by 63+/-2% and 74+/-4%, respectively). None of the C18 column fractions of 50 hFF samples had any significant effect on NAD(+)-dependent 11beta-dehydrogenase activities. The hydrophobic inhibitors of NADP(H)-dependent cortisol-cortisone metabolism did not co-elute with several candidate compounds (prostaglandins E(2) and F(2alpha), cortisol, cortisone, oestradiol, testosterone, progesterone, pregnenolone or cholesterol). Hence, hFF aspirated from women undergoing controlled ovarian hyperstimulation for assisted conception contains both hydrophilic stimuli and hydrophobic inhibitors of glucocorticoid metabolism which appear to be selective for the NADP(H)-dependent, type 1 isoform of 11betaHSD.

Lactate dehydrogenase estimation in follicular fluid: correlation with patient age, follicle size and super ovulation in ART cycles

OBJECTIVE

To quantify the lactate dehydrogenase (LDH) level in human follicular fluids, and to define its relationship with follicle size, patient age, serum estradiol (E(2)) level, and the amount of gonadotropins administered during superovulation in ART cycles.

STUDY DESIGN

In this prospective study, 21 women undergoing ART treatment were selected. Follicular fluid from the largest follicle of both ovaries was collected from each patient on the day of oocyte aspiration and analyzed for LDH. Serum oestradiol was estimated on the day of hCG administration. Relationship between LDH level and (1) patient age, (2) follicle size, (3) follicle stimulating hormone administered during superovulation period and (4) serum oestradiol was studied.

RESULT(S)

LDH activity increased with chronological age of the patient. As follicular size (diameter) increased, increase in the LDH concentration in follicular fluid was observed. Serum estradiol level did not show any relationship with LDH activity. Similarly, administration of various doses of follicle stimulating hormone during superovulation did not show any correlation with LDH level.

CONCLUSION(S)

Follicular fluid LDH level has shown association with patient age and the follicle size, however, no significant association was found with other parameters studied.

Presence of angiotensin-converting enzyme in follicular fluids of porcine ovaries and its possible involvement in the intrafollicular breakdown of bradykinin

The follicular fluid of porcine ovaries contains a metalloenzyme capable of hydrolyzing the synthetic substrate, benzyloxycarbonyl-Val-Lys-Met-MCA. This enzyme was purified by ammonium sulfate fractionation followed by column chromatography on DEAE-cellulose, CM-cellulose, Zn(2+)-chelating Cellulofine, and Diol-300 gel-filtration columns. The molecular weight of the purified enzyme was estimated to be 170,000 by SDS-PAGE and 400,000 by gel-filtration analysis, suggesting that the native enzyme is a dimer of the 170-kDa subunit polypeptide. The enzyme activity was drastically enhanced by the presence of chloride ion, and strongly inhibited by captopril and bradykinin potentiator B. A 9-residue peptide containing a processing site of human amyloid precursor protein was degraded by its dipeptidyl carboxypeptidase activity. Furthermore, the purified protein was recognized by specific antibody raised against human angiotensin-converting enzyme. The enzyme rapidly degraded bradykinin in vitro. These results indicate that benzyloxycarbonyl-Val-Lys-Met-MCA-hydrolyzing enzyme is a porcine angiotensin-converting enzyme, and that the enzyme may play a role in bradykinin turnover within the follicles of porcine ovaries.

Angiotensin converting enzyme in bovine ovarian follicular fluid and its relationship with oestradiol and progesterone

CONTENT

The purpose of the present study was to identify angiotensin converting enzyme (ACE) in bovine ovarian follicular fluid and to relate the ACE activity to the phase of the oestrous cycle, pregnancy, and the follicular fluid concentrations of oestradiol and progesterone. The ACE activity was similar to that found in bovine serum and was completely inhibited by the specific ACE inhibitor captopril. The 50% inhibitory concentration (IC50) was 1.4 x 10(-8) mol/l (range 0.8 x 10(-8) to 5.0 x 10(-8) mol/l; n=6), which is similar to that found in bovine and human serum. The ACE activity did not differ in the pre-ovulatory and luteal phase, pregnancy or cystic follicles. It correlated with the follicular fluid concentration of progesterone in cycling cows (rho=0.476; p < 0.005; n=36), but did not correlate with the diameter of the follicles, the follicular fluid concentration of oestradiol or the ratio between the oestradiol and progesterone concentrations. The demonstration of ACE in bovine ovarian follicular fluid provides further evidence for the presence of a local renin-angiotensin system in the bovine ovary.

Expression and distribution of cyclooxygenase-2 in human periovulatory ovary

Cyclooxygenase, which converts arachidonic acid into prostaglandins, has two types of isoforms, cyclooxygenase-1 and cyclooxygenase-2 (COX-2). The latter is thought to be essential for the ovulatory mechanism. However, expression or distribution of COX-2 in periovulatory human ovary has not been reported. The aim of our study was to examine COX-2 expression and distribution in pre- and postovulatory human ovary. COX-2 was detected by Western blot analysis of pre-ovulatory human ovarian follicular fluid. The levels of COX-2 in preovulatory fluid obtained from 20 subjects underwent in vitro fertilization and embryo transfer, and were assayed using enzyme immunoassay for human COX-2. The results showed 7.3+/-4.1 ng/ml (mean +/- SD) with a COX-2 level range of 2.7 to 19.5 ng/ml of follicular fluid. Detection of COX-2 is considered to reflect its production in the preovulatory follicle. Immunofluorescence microscopic examination of an ovary obtained from a woman at the postovulatory period showed distribution of COX-2 in interstitial but not in granulosa cells in a ruptured follicle. These findings collectively suggest the possibility that COX-2 is mainly produced in follicles in a preovulatory phase, while after ovulation, COX-2 is produced in interstitial cells in human ovary.

Bovine follicular fluid and serum share a unique isoform of matrix metalloproteinase-2 that is degraded by the oviductal fluid

Whereas the mammalian fertilization environment consists of possible products of the mutual interaction between oviductal and follicular fluids in addition to both fluid components, little is known regarding the interaction. In the present study, we have demonstrated that a mutual interaction occurs, resulting in the biochemical changes of follicular fluid components. Gelatin zymographic analyses of bovine follicular fluid (bFF) showed consistently a distinct, gelatinolytic activity having a molecular weight of 110 kDa (GA110) in addition to other gelatinases, whereas bovine oviductal fluid (bOF) showed a lack of GA110. Surprisingly, when bFF was mixed with bOF before zymography, the GA110 of bFF mostly disappeared at a 1:1 (v/v) mixture, completely disappeared at a 1:10 mixture, as fast as within 30 min after mixing. Other bFF gelatinase activities were not affected by bOF at 1:1 or 10:1 mixtures. Addition of EDTA or phenanthroline, but not of phenylmethylsulfonyl fluoride or trypsin inhibitor, to the mixture greatly increased the gelatinolytic activity of bFF GA110. The increased activity of bFF GA110 by EDTA was again abolished by subsequent bOF treatment. Addition of aminophenylmercuric acetate to the EDTA-treated bFF also abolished GA110; however, this was accompanied by the disappearance of other gelatinases, except the 62-kDa gelatinase, the activity of which increased as the treatment continued up to 24 h. Addition of EDTA or phenanthroline to the gelatin gel incubation buffer after electrophoresis abolished almost all gelatinases of bFF, except those of 88-84 kDa, demonstrating that they were indeed gelatinases or isoforms. Bovine serum and fetal bovine serum also showed the presence of GA110, the activity of which was increased by EDTA. However, ovarian granulosa cell homogenate did not exhibit GA110. Immunoblot experiments using antibodies against matrix metalloproteinase (MMP)-2 and MMP-9 demonstrated that bFF GA110 was an isoform of MMP-2, and that the 62-kDa form was an active form of MMP-2. Disappearance of immunoreactive GA110 of bFF and serum by bOF was also observed. Based on these observations, we conclude that bFF and bovine serum share a unique isoform of MMP-2, and that bOF can specifically degrade the isoform, suggesting that a mutual interaction between bFF and bOF could occur at the time of ovulation.

Localization of the renin-angiotensin system in the bovine ovary: cyclic variation of the angiotensin II receptor expression

Angiotensin (Ang) II may modulate reproductive function in the bovine ovary. Therefore, expression and localization of a local ovarian renin-angiotensin system (RAS) were investigated by elucidating the influence of the estrus cycle, pregnancy, and the presence of follicular cysts. Receptor analysis and autoradiography were used to characterize and localize Ang II receptors. Cyclic variations in the density of ovarian Ang II receptors were found with a higher value in estrus than in diestrus. The density in ovaries with follicular cysts was in the same order of magnitude as in estrus. The Ang II receptor type 2 (AT(2)) dominated in all three groups. Autoradiography showed that the majority of antral follicles and follicular cysts had intense AT(2) receptor binding in the theca externa. Binding was less intense in the theca interna, whereas there was no binding in the granulosa layer. In the corpora lutea, the AT(2) receptor was dominant in the capsule and in connective tissue infoldings, whereas no binding was observed in the luteal tissue. The type 1 Ang II receptor (AT(1)) was dominant in the stroma and showed no cyclic changes. Angiotensin-converting enzyme (ACE) activity was detected in all aspirated follicular fluids and homogenates of ovarian tissue. Autoradiography showed that most of the ACE was localized on endothelial cells. Renin immunoreactivity was found in granulosa and thecal cells of antral follicles and in luteal cells. Furthermore, solitary cells in the stroma, presumably macrophages, displayed intense staining. Our finding of cyclic changes support the concept of an active and regulated RAS in the bovine ovary.

Role of gelatinase on follicular atresia in the bovine ovary

Follicular atresia, like follicular growth and ovulation, is characterized by excessive tissue remodeling. It is hypothesized that probably one of the tissue-remodeling enzymes, such as the gelatinases, could be playing an important role in this process. The present study was undertaken to determine the role of gelatinase on follicular atresia in the cow. Follicles of 2-6 mm in diameter were dissected from ovaries, and follicular fluid was categorized according to the morphological appearance of the cumulus-oocyte complexes. Gelatinase activity within the follicular fluid was analyzed by gelatin zymography, and film in situ zymography was employed in order to localize gelatinase. TUNEL was performed on cryosectioned ovaries to understand follicular health. The concentrations of steroids in follicular fluid were also measured by solid phase fluoroimmunoassay. ProMMP-2 was detected in all normal and atretic categories of follicular fluid. The active form of MMP-2 and an additional band of proMMP-9 were detected only in atretic follicular fluid. Gelatinase activity was recorded in both granulosa cells (GCs) and theca cells (TCs) but were found in comparatively higher numbers in those follicles that exhibited a thinned and partially detached granulosa layer. TUNEL confirmed that apoptosis had commenced in the GCs of follicles of the latter category. The estradiol-17beta (E(2)):progesterone (P(4)) ratio was found to be significantly lower in atretic follicles than in normal follicles. These results suggest a plausible role for gelatinase in follicular health, especially the active form of MMP-2 and proMMP-9, and that bovine follicular fluid may be a key indicator of atresia.

Proteolysis of insulin-like growth factor binding proteins during preovulatory follicular development in cattle

The present study was conducted to evaluate changes in follicular fluid (FF) insulin-like growth factor binding protein (IGFBP) proteolytic activity and levels of steroids and IGFBP during follicular development in cattle. Estrous cycles of cows were synchronized with two injections of prostaglandin F2alpha (PGF) 11 d apart and follicular growth monitored via daily rectal ultrasonography in order to identify the dominant follicle. All cows were ovariectomized 48 hr after the second injection of PGF. Follicular fluid was collected individually for all follicles > 5 mm and pooled for small (1 to 5 mm) follicles. Follicular fluid estradiol and androstenedione levels were greater (P < 0.05) and progesterone and IGFBP-3 levels not different (P > 0.10) in large dominant than in small (1 to 5 mm) or large (>5 mm) subordinate follicles, whereas IGFBP-2, -4 and -5 levels were less (P < 0.05) in large dominant than in small or large subordinate follicles. To evaluate proteolysis of IGFBPs, FF was incubated with recombinant human (125) I-labeled IGFBP-2, -3, -4, and -5 and proteins separated by 12% SDS-PAGE. Follicular fluid caused little or no proteolysis of (125)I-lableled IGFBP-2 or -3. However, cleavage of (125)I-labeled IGFBP-4 and -5 by FF from large dominant follicles was greater (P < 0.05) than by FF from small or large subordinate follicles indicating that a protease to IGFBP-4 and -5 exists in estrogen dominant follicles. We conclude that lower levels of IGFBP-2 in estrogen dominant follicles of cattle are not due to increased proteolysis, whereas decreases in IGFBP-4 and -5 levels are likely due, in part, to increased protease activity. Changes in IGFBP may alter levels of bioavailable IGFs that stimulate steroidogenesis and mitogenesis in developing bovine follicles.

Haptoglobin inhibits lecithin-cholesterol acyltransferase in human ovarian follicular fluid

The activity of the enzyme lecithin-cholesterol acyltransferase (LCAT; E.C. 2.3.1.43) is involved in the removal of cholesterol excess from peripheral cells. This activity is stimulated by the HDL (high density lipoprotein) apolipoprotein A1 (ApoA1). Haptoglobin (Hpt) was previously found to be associated with ApoA1 in ovarian follicular fluid. LCAT activity was analyzed in follicular fluids, collected from an IVF program, containing different amounts of Hpt or Hpt/ApoA1 ratio. Addition of purified Hpt to follicular fluid caused a decrease in the enzyme activity, which was measured as the rate of synthesis of cholesteryl esters. In the fractions of fluid proteins, as obtained by gel filtration chromatography, Hpt and HDL were titrated by ELISA while the LCAT activity was assayed by using radioactive cholesterol and purified HDL. When isolated LCAT was incubated with fractions containing different Hpt/ApoA1 ratios, the enzyme activity was found negatively correlated with the Hpt/ApoA1 ratio (P < 0.01). LCAT kinetic parameters were measured in two fractions with the same amount of ApoA1 (5 microg/ml) but different amounts of Hpt (0.69 or 3.77 microg/ml): the V(max) did not change while the K(m) values were 24.1 or 78.6 microM in the presence of the low or high Hpt level, respectively. The analysis of fluids associated with cytoplasmically mature MII oocytes, in a cross-sectional study, confirmed that a negative correlation exists between the Hpt/ApoA1 ratio and the LCAT activity (P < 0.01). The results suggest that Hpt inhibits the reverse transport of cholesterol by preventing ApoA1 stimulation of the LCAT activity.

Secretion of matrix metalloproteinases 2 and 9 and tissue inhibitor of metalloproteinases into follicular fluid during follicle development in equine ovaries

Extensive tissue remodelling is required in equine ovaries for follicle growth and development and also migration of the follicle to the ovulatory fossa, where ovulation occurs. The mechanisms for these processes are largely unexplored. Matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs) are important for control of breakdown of extracellular matrix during tissue remodelling. The aims of this study were to determine the pattern and sites of secretion of the gelatinases MMP-2 and -9 and TIMPs into follicular fluid during follicle development in mare ovaries. The predominant gelatinase detected in follicular fluid was MMP-2, which was present in similar amounts throughout follicular development, as demonstrated by zymography. MMP-9 was also present in follicular fluid and secretion increased significantly (P < 0.05) with development of follicles from < 10 mm to 11-20 mm in diameter. Follicular fluid also contained TIMP-1, TIMP-2, unglycosylated and glycosylated TIMP-3, and TIMP-4, as shown by reverse zymography. The abundance of TIMPs remained largely unchanged during follicle development. MMP-2 and -9 were localized by immunohistochemistry to stromal cells and granulosa and theca cells. TIMP-1, -2, -3 and -4 were present in granulosa and theca cells of the follicle and in stromal cells and also associated with extracellular matrix of the ovarian stromal tissue. The MMPs and TIMPs are likely to be involved in the regulation of the breakdown of extracellular matrix during tissue remodelling for follicle development and migration to the ovulation fossa in mares.

Development-related increase in cortisol biosynthesis by human granulosa cells

Antiinflammatory mechanisms are important in ovulation and may be regulated by cortisol (F). We previously showed that after administration of human (h)CG for ovulation induction, luteinized granulosa cells (LGC) abundantly express 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1) messenger RNA but not 11betaHSD type 2 (11betaHSD2) messenger RNA. 11ssHSD1 is responsible for the reversible formation of antiinflammatory F from its inactive precursor cortisone (E), whereas 11betaHSD2 unidirectionally converts F to E through 11-oxidation. This pattern of gene expression predicts that LGC from periovulatory follicles would show increased activation of E to F, compared with granulosa cells from immature follicles (IGC), and that follicular fluid concentrations of E and F would alter accordingly. To test this hypothesis, we isolated IGC, thecal cells (TC), and follicular fluid, from ovaries of cyclic women, removed during surgery for benign gynecological disease. LGC and follicular fluid were aspirated from periovulatory follicles, 35 h after hCG injection, in patients undergoing in vitro fertilization treatment. In an 11betaHSD assay based on interconversion of tritiated E and F by cell suspensions in vitro, IGC (% conversion, 0.6 +/- 0.4, mean +/- SEM) and collagenase-dispersed TC (0.2 +/- 0.1%) were unable to convert E to F, whereas LGC (36.3 +/- 3.7%) were highly efficient at this reaction. Immature granulosa cells, LGC, and (to a lesser extent) TC were all able to convert F to E. Correspondingly, follicular fluid concentrations of total F and F:E ratios were significantly higher in periovulatory follicles, compared with immature follicles. Culturing IGC for 48 h in the presence of hFSH resulted in increased 11betaHSD1 reductase activity, paralleling stimulation of estrogen (aromatase activity) and progesterone biosynthesis. Similar treatment with hLH did not influence 11betaHSD1 reductase activity, except in a patient with more mature IGC, which also showed a significant increase in E-to-F conversion, as well as progesterone synthesis in response to hLH. These data confirm that 11betaHSD activity in the human ovary is developmentally regulated and gonadotropin responsive, favoring metabolism of F to E in immature follicles and E to F in periovulatory follicles. Increased formation of F by LGC in periovulatory follicles is consistent with an antiinflammatory function for this glucocorticoid at ovulation.

Insulin-like growth factor (IGF)-binding protein-4 proteolytic degradation in bovine, equine, and porcine preovulatory follicles: regulation by IGFs and heparin-binding domain-containing peptides

We recently showed that insulin-like growth factor-binding protein-4 (IGFBP-4) proteolytic degradation in ovine preovulatory ovarian follicles is IGF-dependent and regulated by the heparin-binding domain (HBD) from IGFBP-3 and from connective tissue growth factor (CTGF), heparan/heparin-interacting protein (HIP), and vitronectin. The present study investigated regulation of IGFBP-4 proteolytic degradation in porcine, bovine, and equine ovarian preovulatory follicles. Follicular fluid from such preovulatory follicles contains proteolytic activity, degrading exogenous IGFBP-4. An excess of IGF-I enhanced IGFBP-4 degradation. In contrast, IGFBP-2 or -3 or monoclonal antibodies against IGF-I or -II dose-dependently inhibited IGFBP-4 degradation, and IGF-I or -II reversed this inhibition in a dose-dependent manner. Heparin-binding peptides derived from the C-terminal domain of IGFBP-3 or -5 inhibited IGFBP-4 degradation. Other heparin-binding peptides derived from CTGF, HIP, and vitronectin also inhibited IGFBP-4 degradation, except in porcine follicles. Finally, IGFBP-3 that was mutated in its HBD was less effective at inhibiting IGFBP-4 degradation. Thus, in bovine, porcine, and equine preovulatory follicles, IGFBP-4 proteolytic degradation both depends on IGFs and is inhibited by peptides containing HBD. Overall, these results suggest that during terminal development of follicles to the preovulatory stage in domestic animal species, the increase in IGF bioavailability might enhance IGFBP-4 degradation. In contrast, in atretic follicles, the decrease in IGF bioavailability, resulting partly from the increase in IGFBP-2 (sow, heifer, mare) and IGFBP-5 (heifer) expression would participate in the decrease of IGFBP-4 degradation. In bovine atretic follicles, IGFBP-5 would also strengthen the inhibition of IGFBP-4 degradation by direct interaction of its HBD with the protease. The involvement of other HBD-containing proteins in the modulation of intrafollicular proteases degrading IGFBP-4 remains to be investigated.

Ovine follicular fluid inhibits aromatase activity

"Within follicle" regulations may be important for the fine tuning of gonadotrophin action in ovarian follicles. While numerous growth factors, steroids or proteins which are present in follicular fluid have been shown to have the ability of positively or negatively affecting follicle function, the net effect of follicular fluid of the dominant follicle on its function is unclear.A bioassay measuring aromatase activity of follicular walls was used (1) to check whether follicular fluid from dominant follicles can alter aromatase activity (2), to check how follicle size, atresia and specific gonadotrophins alter the effects of follicular fluid (3), to identify the nature (steroid or protein) of the active compound(s), and (4) to check whether the inhibition is specific of aromatase. Dominant follicular fluid had the ability to reduce aromatase activity. This effect was dose dependent and was obvious whether or not a protease inhibitor was added to the incubation medium. There was no difference in the magnitude of the inhibitory effect of follicular fluid when FSH (2 ng/ml) or no FSH was added to the incubation medium. LH, however, could potentialise the inhibitory effects of follicular fluid. Dominant follicular fluid was more potent to inhibit aromatase than follicular fluid from atretic follicles. Medium conditioned by granulosa cells, but not by theca cells could inhibit aromatase activity when added to the incubation medium. Charcoal treatment of dominant follicular fluid did not remove its inhibitory potential. Fractionation of dominant follicular fluid by a desalting column demonstrated that the inhibition was related to a compound(s) > 10 kDa. Finally, the effect of dominant follicular fluid on aromatase appears specific of this enzyme as follicular fluid does not affect androgen output by thecal shells or progesterone output by luteal cells. Further research is required to check whether the activity observed in dominant follicular fluid is related to compounds known to affect aromatase activity (inhibin, mullerian inhibiting substance, heat shock protein 90, superoxyde dismutase) or to another peptide/protein.

Multiparametric study of atresia in ewe antral follicles: histology, flow cytometry, internucleosomal DNA fragmentation, and lysosomal enzyme activities in granulosa cells and follicular fluid

The differential quantitative participation of apoptosis and necrosis in ewe antral follicles of two different sizes, separated in four stages of atresia using macroscopic, histologic, and esteroid quantification methods was assessed. Annexin V binding and propidium iodide (PI) uptake was used to detect healthy live cells (Annexin V negative/PI negative), early apoptotic cells (Annexin V+/PI-), and necrotic or late apoptotic cells (PI+). Additionally we used internucleosomal DNA fragmentation as a quantitative estimate of apoptosis. Presence and distribution of lysosomal enzymes in follicular fluid and granulosa cells was used as a measure of necrotic cell death. DNA flow cytometry and gel electrophoresis were positively correlated with the progression of atresia, small atretic follicles tend to have higher percentages of internucleosomal cleaved DNA than follicles >6 mm. Annexin/PI binding also indicates that apoptosis and necrosis increase with atresia progression, generally apoptosis outweighs necrosis in small follicles. Acid phosphatase and glucosaminidase in follicular fluid of 3-6 mm follicles showed no significant modifications between healthy and initially atretic follicles, and only a small, but significant increase in activity in advancedly atretic follicles. On the contrary, lysosomal enzyme activity in follicles >6 mm showed positive correlation between atresia stages and the activities of acid phosphatase and glucosaminidase in follicular fluid. A similar size-differential behavior was found in free or membrane-bound lysosomal enzyme activity of granulosa cells. Necrosis, but principally apoptosis, were present during all stages of follicular maturation indicating that growth and maturation of ovarian follicles involves a continuous renewal of granulosa cells, regulated by apoptosis. Mechanisms regulating this equilibrium may participate in the final destiny, whether ovulation or atresia of ovarian follicles.

Superoxide dismutase activity in human follicular fluid after controlled ovarian hyperstimulation in women undergoing in vitro fertilization

OBJECTIVE

To determine the activity of superoxide dismutase (SOD) and the total protein concentration in human preovulatory ovarian follicular fluid (FF) in relation to corresponding serum levels and the fertilization capacity of oocytes.

DESIGN

Prospective, observational study.

SETTING

Academic-based center for reproductive medicine.

PATIENT(S)

Twenty-eight female partners of infertile couples, 13 of whom were smokers, undergoing controlled ovarian hyperstimulation for IVF.

INTERVENTION(S)

Blood and follicular fluid samples were collected 34-36 hours after hCG administration.

MAIN OUTCOME MEASURE(S)

Levels of SOD activity and total protein concentrations.

RESULT(S)

Superoxide dismutase activity was present in all the FF studied and mean levels were statistically significantly higher than in serum. Total protein concentrations in serum were statistically significantly correlated with corresponding concentrations in FF. There was no difference in SOD activity between smokers and nonsmokers. Total protein concentrations in FF were marginally and statistically significantly lower in nonsmokers. Follicular fluid from patients whose oocytes did not become fertilized had a statistically significantly higher level of SOD activity than that from patients whose oocytes did become fertilized.

CONCLUSION(S)

Superoxide dismutase activity is present in FF and is higher than in serum. The degree of SOD activity is variable and seems to be inversely related to the fertilization of oocytes.

Evidence that the insulin-like growth factor binding protein-4 protease in human ovarian follicular fluid is pregnancy associated plasma protein-A

Ovarian insulin-like growth factor binding protein-4 (IGFBP-4) proteolysis is involved in the regulation of follicular development, but until now the identity of the responsible enzyme was unknown. In this study, we identify the IGFBP4 protease in human follicular fluid as pregnancy associated plasma protein-A (PAPP-A) based on distinctive IGFBP-4 cleavage pattern, the same protease inhibitor profile, specific inhibition and immunodepletion of IGFBP-4 protease activity with PAPP-A polyclonal antibodies, and immunorecognition by PAPP-A monoclonal antibodies in ELISA. Furthermore, PAPP-A levels in estrogen-dominant and androgen-dominant follicular fluids reflect their IGFBP-4 proteolytic activity. PAPP-A was also secreted by human granulosa cells, the reputed source of IGFBP-4 protease activity in follicular fluid. We have the molecular and biochemical tools to begin to delineate the regulation and biological function of PAPP-A in normal and dysregulated follicular development and atresia.

Production of lysophosphatidic acids by lysophospholipase D in human follicular fluids of In vitro fertilization patients

Lysophosphatidic acids (LPAs) are known to be normal constituents of mammalian serum, and they mimic some biological effects of the serum. We previously reported that lysophospholipase D (LPLD) was involved in the accumulation of LPAs in incubated rat plasma and serum. In this study we detected, by gas-liquid chromatography, various molecular species of LPA in follicular fluids collected from women programmed for in vitro fertilization. When the follicular fluid was incubated at 37 degrees C for 48 h, persistent increases in the amounts of LPAs were observed concomitant with decreases in the amounts of the corresponding lysophosphatidylcholines (LPCs), although the concentrations of saturated LPCs increased in the first 6 h of incubation. These results suggest that human follicular fluid has LPLD activity, and this was confirmed by experiments with follicular fluids mixed with an exogenous radioactive LPC. The LPLD showed preference for unsaturated over saturated LPCs, similar to plasma LPLD, indicating that it originated from the circulation.

Aromatase activity of human granulosa cells in vitro: effects of gonadotrophins and follicular fluid

The aim of this study was to assess whether human dominant follicular fluid has the ability to modulate aromatase activity and/or granulosa cell proliferation. Dominant follicular fluid was obtained by laparoscopy before the luteinizing hormone surge in naturally cycling women while granulosa cells used in the tests were obtained from in-vitro fertilization patients. Aromatase was measured by the tritiated water release assay, following a 48 h incubation with follicular fluid and serum, and expressed for 5x10(4) granulosa cells. The effects of a range of follicular fluid or serum concentrations (2.5, 5, 10 and 20%) were compared. A decrease in aromatase activity was observed when high follicular fluid concentrations (20%) (P < 0.01) were added. Low concentrations (2.5%) of follicular fluid significantly increased cell proliferation (P < 0.01) as compared to basal values (0%). No further stimulation was however observed when concentrations increased up to 20%. Further characterization of these compounds is required to understand how they may modulate maturation of the dominant follicle.

[Molecular dynamics of human intrafollicular plasma kallikrein and the mechanism of activation of tissue-type plasminogen activator (tPA) in ovarian follicles]

Tissue-type plasminogen activator (tPA)/plasmin system is generally believed to play an important role in follicle wall degradation upon ovulation. For examination of the proteolytic activation of tPA within the follicle, human plasma kallikrein (hPK) was purified from preovulatory follicular fluid obtained from women hyperstimulated by GnRHa-hMG-hCG in in vitro fertilization procedures. After ammonium sulfate fractionation, three enzyme fractions were isolated in the DEAE-cellulose ionic exchange column chromatography. Each fraction was further purified by various column chromatographies using CM-cellulose, benzamidine-Sepharose 6B, heparin-Cellulofine, and Sephacryl S-300. Enzymatic (substrate specificity, susceptibility to various proteinase inhibitors), electrophoretic, and immunological characterization of the enzymes revealed that they were hPK in free form (Mr = 89,000-90,000), in complex with alpha 2-macroglobulin (Mr = 730,000), and a newly-found isoform of pPK (Mr = 80,000-87,000). Each fraction was capable to convert human single-chain tPA (sctPA) to its active two-chain form. The present data also demonstrates that the activation of tPA by the alpha 2-macroglobulin fraction is due to the action of a bound proteinase distinct from hPK, indicating the presence of an additional tPA activator. These proteinases are presumably involved in triggering of the tPA/plasmin system by activating tPA upon ovulation.

Identification and partial characterization of a metallopeptidase from porcine ovaries

The follicular fluid of porcine ovaries contains an EDTA-sensitive enzyme activity for the synthetic substrate benzyloxycarbonyl-Val-Lys-Met-4-methylcoumaryl-7-amide. To investigate its characteristics and its identification, the enzyme was partially purified by ammonium sulfate fractionation followed by column chromatographies on DEAE-Cellulose and chelating Cellulofine columns. The enzyme activity was strongly inhibited by typical chelators, such as EDTA and o-phenanthroline, but after inhibition by EDTA the activity was completely restored with an appropriate amount of Zn2+ and Co2+ ions. It showed enzyme activity solely for benzyloxycarbonyl-Val-Lys-Met-4-methylcoumaryl-7-amide among the substrates tested. The molecular weight of the enzyme was estimated to be 400,000 by gel filtration. The enzyme activity in the fluid obtained from large follicles of porcine ovaries was significantly higher than that from smaller follicles. It appeared that the granulosa cell extract did not contain the metalloenzyme activity. Similar enzyme activities were detected in follicular fluids from bovine and human ovaries. These results suggest that the present enzyme is distinct from any other metalloendopeptidases thus far reported.

Carbonic anhydrase isoenzymes CAI and CAII in semen, decidua, chorionic villi and various fetal tissues

ELISA methods were used to determine the concentrations of CAI and CAII in spermatozoa, seminal plasma, ovarian follicular fluid, decidual tissues, chorionic villi and various fetal tissues at 8-11 weeks gestation. Both CAI and CAII were expressed in all subjects except ovarian follicular fluid samples. The possible physiological role(s) of carbonic anhydrases in fertilization, implantation and fetal development are discussed.

Localization of prolyl endopeptidase mRNA in small growing follicles of porcine ovary

Prolyl endopeptidase (EC3.4.21.26) has been considered a unique intracellular enzyme catalyzing internal peptide bond hydrolysis of Pro-X. In this study, the distribution of prolyl endopeptidase activity and its mRNA was investigated in the follicles of porcine ovary. Both follicular fluid and granulosa cell fractions from small follicles showed higher activity than those from large follicles. Molecular cloning and Northern blot analysis suggested that only one species of prolyl endopeptidase gene was expressed in the ovary. In addition, in situ hybridization study revealed that the prolyl endopeptidase mRNA expression was more noticeable in the granulosa cell layers of small ovarian follicles than in those of large follicles, suggesting its importance in the early stage of follicular development.

Aromatase mRNA expression in individual follicles from polycystic ovaries

Polycystic ovary syndrome (PCOS) is a common reproductive disorder characterized by arrested follicular development prior to selection of a dominant follicle. Dominant follicles produce large amounts of oestradiol but PCOS follicles do not. With several potential aromatase (P450AROM) inhibitors in follicular fluid, the question arises whether P450AROM is expressed in PCOS granulosa cells, but the activity is inhibited, or whether P450AROM is not expressed in PCOS. The purpose of the present study was to determine whether P450AROM mRNA expression is altered in PCOS and to correlate P450AROM mRNA expression in individual follicles with aromatase stimulatory bioactivity and oestradiol in the follicular microenvironments. P450AROM mRNA was measured in individual follicles from 16 PCOS and 48 regularly cycling control women by quantitative polymerase chain reaction (PCR) and correlated with follicular fluid oestradiol concentrations and aromatase stimulating bioactivity measured by the rat granulosa cells aromatase bioassay. Follicular fluid oestradiol was low in all control follicles <7 mm in diameter. Some follicles > or = 7 mm contained elevated oestradiol values (P < 0.01) and all had an androstenedione:oestradiol ratio of <4. Only in granulosa cells from follicles > or = 7 mm with an androstenedione:oestradiol ratio of <4 were P450AROM mRNA levels increased (P < 0.05). These same follicles also contained increased levels of aromatase stimulating bioactivity whereas follicles <7 mm or with androstenedione:oestradiol ratio of >4 contained little or no bioactivity. All PCOS follicles contained low levels of oestradiol, P450AROM mRNA and aromatase stimulating bioactivity similar to size-matched control follicles. These data indicate that P450AROM mRNA expression and oestradiol production begin in developing follicles when they reach approximately 7 mm in diameter. Oestradiol production is low in PCOS follicles because there is insufficient aromatase stimulating bioactivity to increase P450AROM mRNA expression.

Glutathione S-transferases in human ovarian follicular fluid

OBJECTIVE

To study the levels of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 in human preovulatory ovarian follicular fluid (FF) and pooled granulosa and cumulus cells.

DESIGN

The relation of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 with P and 17 beta-E2 concentrations were studied.

SETTING

The Department of Obstetrics and Gynecology, the Department of Gastroenterology, and the Laboratory of Endocrinology and Reproduction of the University Hospital Nijmegen in Nijmegen, the Netherlands.

PATIENT(S)

Infertile women participating in an IVF program.

RESULT(S)

Detectable amounts of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 were found in ovarian FF and pooled cumulus and granulosa cells. Concentrations of glutathione S-transferase Alpha 1-1 were always much higher than those of glutathione S-transferase Pi 1-1. Both ovarian FF concentrations of glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 did not correlate with ovarian FF concentrations of 17 beta-E2 and P.

CONCLUSION(S)

The high FF concentrations of glutathione S-transferase Pi 1-1 and especially of glutathione S-transferase Alpha 1-1 suggest that these enzymes may play an important role in the detoxification processes in the follicles. The lack of correlation between follicular P and 17 beta-E2 and glutathione S-transferase Alpha 1-1 and glutathione S-transferase Pi 1-1 indicates that both enzymes presumably are not present as a result of the high steroid levels.