Progesterone stimulates expression of follistatin splice variants Fst288 and Fst315 in the mouse uterus

Follistatin, an inhibitor of activin A, has key regulatory roles in the female reproductive tract. Follistatin has two splice variants: FST288, largely associated with cell surfaces, and FST315, the predominant circulating form. The mechanism regulating uterine expression of these variants is unknown. Quantitative RT-PCR was used to measure expression of follistatin splice variants (Fst288, Fst315), the activin bA subunit (Inhba) and the inhibin a subunit (Inha) in uterine tissues during early pregnancy (days 1–4, preimplantation) and in response to exogenous 17b-oestradiol (single s.c. injection) and progesterone (three daily s.c. injections) in ovariectomized mice. Uterine Fst288, Fst315 and Inhba expression increased during early pregnancy, with greater increases in Fst315 relative to Fst288 suggesting differential regulation of these variants. Fst288, Fst315, Inhba and Inha all increased in response to progesterone treatment. Fst288, but not Fst315, mRNA decreased in response to 17b-oestradiol treatment, whereas Inhba increased. A comparison of the absolute concentrations of uterine follistatin mRNA using crossing thresholds indicated that both variants were more highly expressed in early pregnancy in contrast to the hormone treatment models. It is concluded that progesterone regulates uterine expression of both follistatin variants, as well as activin A, during early pregnancy in the mouse uterus

531. Lyve-1 AND Vegfr-3 POSITIVE LYMPHATIC VESSELS ARE LARGELY RESTRICTED TO THE MYOMETRIUM IN THE MOUSE UTERUS

The human endometrium contains a distinct population of lymphatic vessels, with reduced numbers of vessel profiles in the functionalis relative to the basalis and underlying myometrium. The mechanisms restricting lymphatic vessel development within the functionalis and the consequences of this distribution for endometrial function have not been investigated. To determine how the distribution of endometrial lymphatics is regulated, an in vivo animal model is required for mechanistic studies. As an initial step, we described the distribution of lymphatic vessels and the expression of Vegf-C and Vegf-D within the mouse uterus using immunohistochemistry. Uterine tissues were collected from mice during the oestrus cycle (diestrus, proestrus and oestrus, n=7–9 per group), during early pregnancy (days 1-4, n = 4–5 per group), and from ovariectomised mice treated with vehicle, estradiol-17β or progesterone treatment (n=7–8 per group). Uterine sections were immunostained with antibodies against Lyve-1, Vegfr3, Vegf-C and Vegf-D. Lyve-1 positive lymphatic vessels were almost exclusively observed in the connective tissue between the longitudinal and circular muscle layers of the myometrium. Lymphatic vessel profiles were rare within the endometrium and were only observed on 24 % of the sections examined. The Vegfr3 immunostaining was less robust than Lyve-1 with considerable variation in non-lymphatic staining among the different sections (which did not relate to a particular reproductive state or treatment group). Despite the variability, the pattern of lymphatic vessels was as seen with the Lyve-1 antibody. Vegf-C and Vegf-D immunostaining was present in all uterine compartments (epithelium, stroma, myometrium), however, only minimal changes were noted in expression across the oestrus cycle, during early pregnancy, or in hormone treated mice. In conclusion, despite the presence of the key lymphangiogenic growth factors Vegf-C and Vegf-D, there are minimal lymphatic vessels present within the mouse endometrium. This implicates other factors in the mechanism restricting endometrial lymphatic vessel growth.

Influence of different hormonal regimens on endometrial microvascular density and VEGF expression in women suffering from breakthrough bleeding

BACKGROUND

The aim of this study was to quantify blood vessel density (BVD) and immunoreactive vascular endothelial growth factor (VEGF) levels in endometrial biopsies taken from women suffering breakthrough bleeding (BTB) under different exogenous hormonal regimes.

METHODS

Endometrial biopsies from women in Melbourne with BTB were divided into four groups: combined-continuous hormone therapy (HT) (estrogen and progestin taken daily), cyclical HT (daily estrogen with progestin for 14 days each cycle), progestin-only, or no HT. Subjects from Barcelona were using the Mirena intrauterine levonorgestrel-releasing system for contraceptive purposes, with menstrual diaries for classification into four groups (amenorrhea, infrequent, regular and prolonged). Control biopsies from Melbourne were included in the study. Endometrial samples were immunostained for VEGF and blood vessel localization using an antibody to CD34.

RESULTS

Results showed that BVD was significantly reduced in the progestin-only treated group compared with the other three treatment groups (P = 0.028). In addition, all four Mirena BTB groups had significantly reduced BVD compared with controls. Considerable heterogeneity was observed in VEGF immunostaining within and between individual samples with no major differences between HT or Mirena.

CONCLUSION

These results provide strong evidence that unopposed progestins reduce endometrial BVD and that there is no link between VEGF immunostaining and BVD or BTB.

Differences between the pre-menopausal and post-menopausal uterine fibroid vasculature

OBJECTIVES

To quantitatively examine differences in microvascular density between fibroid and myometrial tissue from fibroid uteri removed at hysterectomy, both before and after the menopause, and with hormone replacement therapy.

METHODS

Factor VIII immunostaining of formalin fixed tissues was used to identify blood vessels, and the vessels counted by an investigator blinded to tissue type or menopausal status.

RESULTS

The mean myometrial: fibroid MVD ratio was 2.38 higher in the post-menopausal group (95% CI: 0.12, 4.65, p=0.0474) than in the pre-menopausal group, with the hormone therapy (HT)-using post-menopausal group lying in between. An increase in microvascular density in the myometrium after the menopause was responsible for most of the change in ratios seen between the pre and post-menopausal pairs. There was a trend to increasing myometrial MVD with increasing number of years post-menopause.

CONCLUSIONS

Myometrial microvascular density increases markedly after the menopause, while fibroid microvascular density does not alter. Thus, the difference between myometrial and fibroid vasculature becomes greater after the menopause. The implications of this for the treatment of fibroids in post-menopausal women is discussed.

[The price of the drugs in Rome: economy and pharmacy from 1700 till 1870]

Since the Middle Ages pharmacists had played an important role as producers and retailers of drugs, many of them exotic and precious. Proof is the resignation of the church of San Lorenzo by Martin V to the guild of apothecaries. 100 years later, Pope Clemens VII introduced the principle of drug taxes. The first roman tax was published in 1558. Until Garibaldi overthrew the papal state in 1870, these principles had remained the same, only to be interrupted by the French occupation at the beginning of the 19th century. An analysis of the drug prices shows the general development of drug costs between 1700 and 1854, the prices and the drug trade in particular being especially dependent on strong political tendencies. The introduction of new drugs and the omission of old ones had a remarkable effect on the costs, a fact which is represented by a study about the development of the prices comparing different drug groups. A further comparison between the wages and the cost of living explains why mainly members of the higher social classes could afford to buy drugs in pharmacies. This economical study of taxes emphasizes the fact that drugs, in regard to their development in prices, can hardly be compared to other goods.

Focal vascular endothelial growth factor correlates with angiogenesis in human endometrium. Role of intravascular neutrophils

Vascular endothelial growth factor (VEGF) is expressed in human endometrium, but the cellular source of VEGF for endometrial angiogenesis has not been determined. In the present study the relationship between focal VEGF associated with microvessels and endothelial cell proliferation was examined in three layers of human endometrium at various stages of the menstrual cycle (menstrual, proliferative and secretory). Immunohistochemical analysis of full thickness endometrium from 18 hysterectomy samples without endometrial pathology were examined. The percentage of proliferating vessels was higher in proliferative compared to secretory endometrium, but this was only statistically significant in the basalis layer. A significantly greater percentage of VEGF-expressing microvessels was observed in proliferative than secretory endometrium (P < 0.05). The most VEGF-expressing microvessels were observed in the subepithelial capillary plexus, followed by the functionalis and least were present in the basalis. There was a significant correlation between focal VEGF-expressing microvessels and proliferating vessels for the subepithelial capillary plexus (R(s) = 0.70, P = 0.008), the functionalis (R(s) = 0.70, P = 0.001) and the basalis (R(s) = 0.76, P < 0.001). Focal VEGF associated with microvessels was found in marginating and adherent neutrophils. These data suggest that neutrophils in intimate contact with endometrial endothelium may be a source of intravascular VEGF for vessels undergoing angiogenesis by elongation or intussusception, particularly during the proliferative phase of rapid endometrial growth.

Localization of vascular endothelial growth factor-D in malignant melanoma suggests a role in tumour angiogenesis

Expression of angiogenic and lymphangiogenic factors by tumours may influence the route of metastatic spread. Vascular endothelial growth factor (VEGF) is a regulator of tumour angiogenesis, but studies of the inhibition of solid tumour growth by neutralizing anti-VEGF antibodies indicated that other angiogenic factors may be involved. VEGF-D may be an alternative regulator because like VEGF it is angiogenic and it activates VEGF receptor-2 (VEGFR-2), an endothelial cell receptor which is a key signalling molecule in tumour angiogenesis. This study reports the generation of monoclonal antibodies to the receptor-binding domain of VEGF-D and the use of these antibodies to localize VEGF-D in malignant melanoma. VEGF-D was detected in tumour cells and in vessels adjacent to immunopositive tumour cells, but not in vessels distant from the tumours. These findings are consistent with a model in which VEGF-D, secreted by tumour cells, activates endothelial cell receptors and thereby contributes to the regulation of tumour angiogenesis and possibly lymphangiogenesis. In addition, VEGF-D was detected in the vascular smooth muscle, but not the endothelium, of vessels in adult colon. The endothelium of these vessels was negative for VEGFR-2 and VEGFR-3. As VEGF receptors can be up-regulated on endothelium in response to vessel damage and ischaemia, these findings of a specific localization of VEGF-D in smooth muscle of the blood vessels suggest that VEGF-D produced by vascular smooth muscle could play a role in vascular repair by stimulating the proliferation of endothelial cells.

Bcl-2, Fas and caspase 3 expression in endometrium from levonorgestrel implant users with and without breakthrough bleeding

Women using the progestin-only contraceptive Norplant often suffer from unpredictable bouts of breakthrough bleeding, which usually occurs from a thin atrophic endometrium. The role of cellular apoptosis in the endometrial response to Norplant has not been investigated. The aim of the present study was to use immunohistochemistry to produce semi-quantitative scores for expression of the apoptosis-related proteins Bcl-2, Fas and caspase 3 in endometrium from 16 controls and 42 women using Norplant with minimal or major breakthrough bleeding problems. The results showed no difference in endometrial immunostaining for any of the three proteins between Norplant users with and without breakthrough bleeding. There was also no evidence of endometrial endothelial cell immunostaining for any of the proteins. Bcl-2 was the only protein to show a cyclical pattern, with higher expression in the proliferative compared to secretory glands. All three proteins showed different expression levels in control functionalis versus basalis, with the survival protein Bcl-2 being higher in basalis, and the death receptor Fas and the proteolytic enzyme caspase 3 being higher in the functionalis. Overall, the results suggest that apoptosis is regulated differently in functionalis compared to basalis, and that atrophic Norplant-exposed endometrium appears more like functionalis than basalis with respect to expression of Fas and caspase 3. There was no evidence for a role for apoptosis in the mechanisms that underlie progestin-induced endometrial breakthrough bleeding.

Endometrial microvascular growth in normal and dysfunctional states

As a tissue that exhibits rapid cyclical growth and shedding throughout the reproductive life of the female, human endometrium provides a good model for the study of normal physiological angiogenesis. The objective of this paper is to summarize recent data on endometrial vascular growth, present new data on regional variability in endothelial cell proliferation within the endometrium, and interpret this information in light of current knowledge of the mechanisms by which angiogenesis occurs. Conventional angiogenesis normally involves a series of steps which include endothelial cell activation, breakdown of the basement membrane, migration and proliferation of the endothelial cell, fusion of sprouts, and tube formation. Other mechanisms by which angiogenesis occurs include intussusception and vessel elongation. Using immunohistochemical techniques we have shown repeatedly that levels of endothelial cell proliferation within human endometrium do not show any consistent pattern across the different stages of the menstrual cycle, which is unexpected since significant vascular growth must occur during the proliferative phase, when the endometrium increases in thickness by up to 4-fold. There are two possible explanations for this; either there is no obligatory link between endometrial endothelial cell proliferation and new vessel formation, or there is significant variation in endothelial cell proliferation within different regions of the same uterus. Multiple samples from hysterectomy specimens subsequently demonstrated that the variability is due to real differences between individuals, as well as showing that the endothelial cell proliferation index is significantly elevated in functionalis compared with basalis. During these studies we observed that endothelial cell proliferation nearly always appeared inside existing endometrial vessels, rather than be associated with structures that could be identified as vascular sprouts. To explore further whether sprout formation occurs during endometrial angiogenesis, we investigated the immunohistochemical distribution of integrin alphavbeta3 on endometrial endothelial cells. As for endothelial cell proliferation, integrin alphavbeta3 immunostaining was seen only on endothelial cells that appeared within existing blood vessels. The results from these studies have major implications for our understanding of the mechanisms that control endometrial angiogenesis. The lack of correlation between menstrual cycle stage and endothelial cell proliferation index, or endothelial cell expression of integrin alphavbeta3, suggests that vascular growth is not under the overall control of oestrogen and progesterone.

Endometrial vascular smooth muscle oestrogen and progesterone receptor distribution in women with and without menorrhagia

This study tested the hypothesis that alterations in the expression of oestrogen and progesterone receptors (ER and PR) in endometrial vascular smooth muscle cells (VSMC) may play a role in the increased blood loss that occurs during menorrhagia. Subject groups were: controls (n = 40), those with menorrhagia (menstrual blood loss > 80 ml, n = 39) and patients post-endometrial ablation (n = 16). The aims of our study were to describe the changing distribution of VSMC ER and PR during the menstrual cycle and to look for differences between the three groups. Immunohistochemical double-staining results for VSMC and either ER or PR were highly varied, with 0-85% of endometrial arterioles in a biopsy section having alpha smooth muscle actin/ER positive cells, and 0-70% demonstrating PR. There were no significant differences between controls, menorrhagia or post-ablation specimens (analysis of variance for ER P = 0.72; for PR P = 0.17). There were also no significant differences between the different stages of the menstrual cycle when all three groups were combined (analysis of variance for ER P = 0.11; for PR P = 0.13). The high variability found in this study may mask biologically relevant differences in endometrial vascular ER and PR distribution between different groups.