Changes in the extracellular matrix of the normal human breast during the menstrual cycle

Summary The normal human mammary gland undergoes a well defined sequence of histological changes in both epithelial and stromal compartments during the menstrual cycle. Studies in vitro have suggested that the extracellular matrix surrounding the individual cells plays a central role in modulating a wide variety of cellular events, including proliferation, differentiation and gene expression. We therefore investigated the distribution of a number of extracellular matrix molecules in the normal breast during the menstrual cycle. By use of indirect immunofluorescence, with specific antibodies, we demonstrated that laminin, heparan sulphate proteoglycan, type IV collagen, type V collagen, chondroitin sulphate and fibronectin undergo changes in distribution during the menstrual cycle, whereas collagen types I, III, VI and VII remain unchanged. These changes were most marked in the basement membrane, sub-basement membrane zone and delimiting layer of fibroblasts surrounding the ductules where basement membrane markers such as laminin, heparan sulphate proteoglycan, and type IV and V collagens appear greatly reduced during the mid-cycle period (days 8 to 22). These results suggest that some extracellular matrix molecules may act as medittors in the hormonal control of the mammary gland, whereas others may have a predominantly structural role.     

Changes in breast volume during normal menstrual cycle and after oral contraceptives.

The volume of the left and right breasts was measured daily in four nulliparous women during normal menstrual cycles and after the use of oral contraceptives. Breast volume increased significantly in the second half of both normal and contraceptive-controlled cycles. The mean total change in volume throughout the cycle was 100 ml under natural conditions and 66 ml on oral contraceptives.     

Changes in brain size during the menstrual cycle

Background

There is increasing evidence for hormone-dependent modification of function and behavior during the menstrual cycle, but little is known about associated short-term structural alterations of the brain. Preliminary studies suggest that a hormone-dependent decline in brain volume occurs in postmenopausal, or women receiving antiestrogens, long term. Advances in serial MR-volumetry have allowed for the accurate detection of small volume changes of the brain. Recently, activity-induced short-term structural plasticity of the brain was demonstrated, challenging the view that the brain is as rigid as formerly believed.

Methodology/Principal Findings

We used MR-volumetry to investigate short-term brain volume changes across the menstrual cycle in women or a parallel 4 week period in men, respectively. We found a significant grey matter volume peak and CSF loss at the time of ovulation in females. This volume peak did not correlate with estradiol or progesterone hormone levels. Men did not show any significant brain volume alterations.

Conclusions/Significance

These data give evidence of short-term hormone-dependent structural brain changes during the menstrual cycle, which need to be correlated with functional states and have to be considered in structure-associated functional brain research.     

Tenascin distribution in the normal human breast is altered during the menstrual cycle and in carcinoma

Tenascin is a novel extracellular matrix glycoprotein which appears to have a major role in tissue development. Previous studies have stated that tenascin is absent from the normal human, rat and mouse breast, its distribution being restricted to embryonic and malignant mammary tissues. No previous studies have investigated tenascin distribution as a function of the normal menstrual cycle. Therefore this study addresses the cyclical appearance of tenascin in the normal breast and associated changes in distribution in preinvasive cancer (carcinoma-in-situ) and invasive infiltrating ductal carcinoma. Tenascin is present in the normal human adult mammary gland, principally in the basement membrane, sub-basement-membrane zone and delimiting layer of fibroblasts around the ductules. Both the distribution and quantity of tenascin change during the menstrual cycle. In carcinoma-in-situ (preinvasive cancer) tenascin is present in the attenuated basement membrane/sub-basement-membrane zone around the expanded ductules and in small amounts in the stroma. In infiltrating ductal carcinoma, tenascin is absent from the remnants of the basement membrane and sub-basement-membrane zone but greatly increased in the adjacent intralobular and interlobular stroma. Therefore, if tenascin is used as a basement membrane/sub-basement-membrane marker for distinguishing carcinoma-in-situ from invasive ductal carcinoma, the time of the menstrual cycle is of importance in interpreting the biopsy appearance. This study suggests that the optimal time for biopsy is between weeks 3 and 4 of the cycle, to avoid confusion between the normal low levels of tenascin (due to hormonal status) and those due to microinvasive disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lipid metabolism and coagulation during the normal menstrual cycle

To examine the effects of sex-hormones on lipids, lipoproteins and coagulation in the normal menstrual cycle 37 women had blood samples taken early in the follicular phase (low estrogen) at the midcycle (high estrogen) and late in the luteal phase (high estrogen and high progesterone) under the best possible uniform and basal conditions. No significant changes (P greater than 0.05) in lipids and lipoproteins (including the HDL subfractions and apolipoproteins) were found throughout the menstrual cycle. In the coagulation system antithrombin III and factor VII did not change (P greater than 0.05). Fibrinogen, however, showed a significant (P less than 0.05) increase in the luteal phase compared to the follicular phase and midcycle. Fibrinogen showed a significant positive correlation (r = 0.2766; P less than 0.01) with progesterone, so the rise in fibrinogen in the luteal phase could be a progesterone effect. This longitudinal study performed on a large number of women under basal conditions showed that it seems of minor importance to define exact days of the cycle for analysing lipids and lipoproteins e.g. as controls in a study of lipid metabolism in women taking sex-hormones. For coagulation studies the cycle days may, however, be of importance.     

Changes in plasma adrenomedullin levels during the menstrual cycle

We investigated whether the levels of adrenomedullin, a novel peptide produced by several tissues, including the pituitary gland, change during the ovarian cycle. We studied 13 healthy women with regular menstrual cycles. Plasma samples were collected at 7, 14, 21 and 28 days of the ovarian cycle and assayed for adrenomedullin 1-52 using a specific RIA. LH, FSH, 17beta-estradiol, and progesterone concentrations were also determined. The adrenomedullin profile during ovarian cycle was similar to that of LH; plasma adrenomedullin increased from 10.9 pg/ml at the 7th day to 15.1 pg/ml at the 14th, and decreased to 8.5 pg/ml in the subsequent menses. The changes in plasma adrenomedullin were related to changes in LH and 17beta-estradiol. The cause of the increase in adrenomedullin levels during the late follicular phase of the menstrual cycle is not clear. Since it has been demonstrated that adrenomedullin is involved in the regulation of hypothalamus-pituitary-adrenal gland and its secretion is regulated by sex hormones we speculate that adrenomedullin could also play a role in regulating the hypothalamus-pituitary-ovary feedback. Alternatively it may be involved in the regulation of fluid and electrolyte homeostasis during the menstrual cycle.     

Changes in breast sensitivity at puberty,during the menstrual cycle,and at parturition.

Sensitivity to pain and touch was measured in the nipple, areola, and cutaneous breast tissue of prepubertal boys and girls, postpubertal men and nuliparous women before and after delivery. Before puberty there were no differences between the sexes, but after puberty the tactile sensitivity of all areas of the women''s breast was significantly greater than the men''s. Tactil sensitivity of all areas also varied during the menstrual cycle, with maximal sensitivity at midcycle and at menstruation; the mid-cycle peak was absent when the women were taking oral contraceptives. But the most dramatic changes occured within 24 hours of parturition, when there was a great increase in breast sensitivity. This may be the key event for activating the suckling-induced discharge of oxytocin and prolactin and inhibiting ovulation during lactation.     

Fluctuations in human serum lipoproteins during the normal menstrual cycle

1. Lipoproteins were measured in sera from 11 young women having a similar environment and diet. Sera were obtained at weekly intervals over a 12-week period. The values of the lipoproteins during periods in the normal ovulatory cycle were compared to assess their relation to reported hormone concentrations in blood. 2. Only the 4–0s_f (HDL₂) (d 1·125 sodium chloride) fraction changed significantly; it increased at ovulation in ten of the 11 subjects and fell as menstruation approached. 3. There was greater variability in most of the low-density rather than the high-density lipoproteins within individuals. The lipoprotein class most characteristic for an individual was the 4–0s_f or HDL₂ fraction.     

Oestrogen receptor content of normal breast cells and breast carcinomas throughout the menstrual cycle

To examine the presence and distribution of oestrogen receptors in the normal breast during the menstrual cycle cytological samples obtained by fine needle aspiration from 69 premenopausal women with normal breasts were analysed immunocyto-chemically with a monoclonal antibody to oestrogen receptor; samples from 15 postmenopausal women were also analysed. The receptor content of breast cancers from 83 premenopausal women was also determined in relation to when during the menstrual cycle excision was performed. In the normal premenopausal women oestrogen receptors were detected in the nuclei of epithelial cells in 21 out of 68 (31%) assessable samples. All 21 of these samples were obtained from the 35 women who were studied during the first half of their menstrual cycle (days 28 to 14). None of the 33 samples obtained during the second half of the cycle contained oestrogen receptors. Samples were assessable in eight of the postmenopausal women, six giving a positive result for oestrogen receptor. Fifty one of the 83 carcinomas were positive for oestrogen receptor, 24 having been excised during the first half of the cycle and 27 during the second half.Production of oestrogen receptor protein is suppressed at the time of ovulation in the normal breast epithelium of premenopausal women. In contrast, breast carcinoma cells either synthesise this protein continuously throughout the cycle or fail to express it despite fluctuations of serum hormone concentrations.     

Changes of markers of oxidative stress during menstrual cycle

The levels of urinary hydrogen peroxide and thiobarbituric acid reactive substances have been compared during the menstrual cycle of 12 regularly menstruating women. Higher level of both indices of oxidative stress (normalized with respect to creatinine content) were found in the luteal phase of the cycle. These results give further evidence for the usefulness of urinary hydrogen peroxide and thiobarbituric acid reactive substances as potential biomarkers of oxidative stress and for the antioxidant action of estrogens.     

Changes in the density gradient distribution of erythrocytes during the menstrual cycle

Modifications in erythrocyte density distribution were evaluated, by means of centrifugation on Ficoll-Triosil discontinuous density gradient, in five healthy young women during menstrual cycle. Oestradiol and progesterone plasma levels were tested, showing normal and typically ovulatory-like variations during the cycle. Youngest cell populations showed always quantitative increases from the follicular to the ovulatory phase of the cycle, reverting to basal values in the luteal phase. Possible hormonal or haemorrhagic causes are discussed.     

Timing of surgery during the menstrual cycle and prognosis of breast cancer

There are conflicting reports on the differential effect of surgery performed during the two phases of the menstrual cycle, namely, follicular and luteal, and prognosis of operable breast cancer. A statistical meta-analysis of the published evidence suggests a modest survival benefit of 15+/-4% when the operation is performed during the luteal phase. Further research in this area might provide a novel avenue to understand the natural history of breast cancer. A spin off from these studies might be the understanding of the importance of events that occur at the time of surgery in determining long term prognosis.     

Ultrasonographic assessment of the endometrium in rhesus monkeys during the normal menstrual cycle

This study was undertaken to determine whether cyclical changes in the endometrium of the rhesus monkey could be observed by using ultrasound. Three indices of endometrial size were examined: the antero-posterior (or ventro-dorsal), longitudinal, and transverse diameters. Changes in the ultrasonic reflectivity of the endometrium were also assessed. We have attempted to correlate these endometrial parameters with the hormonal status of the animal. Ultrasonography was performed for an average of 12 consecutive days during 19 menstrual cycles. All ultrasonic recordings were normalized to the day of the estradiol (E2) peak (Day 0). We found that the reflectivity of the endometrium was dependent on the stage of the cycle: during the follicular phase, the endometrium appeared less echogenic (darker) compared to the myometrium; in the luteal phase, the endometrium was more echogenic (lighter). During the follicular phase (Days -9 to 0), there was a linear increase in the antero-posterior (p less than 0.001), longitudinal (p less than 0.05), and transverse (p less than 0.001) diameters. In the luteal phase (Days 1-15), no significant changes were observed in these diameters. An estimated endometrial volume (EEV) was obtained by the product of the antero-posterior, longitudinal, and transverse diameters. Each animal observed during the follicular phase (n = 14) exhibited a peak in the EEV, which correlated with the day of the E2 peak (p less than 0.01). From this study, we conclude that the sonographic appearance of the endometrium of the rhesus monkey reflects the cyclical changes that occur during the menstrual cycle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Patterns of estrogen and progesterone receptors in monkey endometrium during the normal menstrual cycle

Total concentrations of estradiol-17β (E₂) and progesterone (P) receptors (R) were measured in the endometrium of rhesus monkeys ($\text{Macaca mulatta}$) during the normal menstrual cycle. The endometrium was collected at abdominal fundal hysterotomy on days 8, 12, 15, 18 and 24 of the menstrual cycle. Visual inspection of the ovaries and measurement of E₂, P, follicle stimulating hormone (FSH) and luteinizing hormone (LH) provided assuredness of normal ovarian function. Exchange procedures were used in order to measure the total concentrations of E₂R and PR in nuclear and cytosol fractions. The pattern of estrogen receptor showed a slight increase in the cytosol and nuclear concentrations at the preovulatory interval. Later, the total E₂R concentration was decreased when P increased during the luteal phase. Cytosol PR synthesis was parallel to the serum E₂ increase during the late follicular phase. Secretion of P by the corpus luteum was accompanied by a rapid nuclear translocation and concomitant decrease in cytoplasmic PR. Thereafter the total PR concentration declined during the second half of the luteal phase. These findings in monkey endometrium are similar to those reported for human endometrium during the normal menstrual cycle and further establish the utility of these surrogate primates in investigations indicative of human endometrial function.     

Gonadocrinin-like activity of the peritoneal fluid during the menstrual cycle in the normal female

Peritoneal fluid formation and composition is under the dependence of the ovarian function. Collection of these fluids was performed by laparoscopy in normal cycling women. After absorption of the steroids, they were tested on monolayer pituitary cell cultures in order to study the influence on gonadotrophin release. LH secretion was stimulated through cell the menstrual cycle without any cycling variations. FSH secretion was also increased, excepted in the immediate post-ovulation period. Thus the Peritoneal fluid contains, as follicular fluid, substances with gonadocrinin- and inhibin-like activity. Gonadocrinin activity was not correlated with estradiol and progesterone levels in serum and peritoneal fluid.