Eosinophil-Associated Gene Pathways but not Eosinophil Numbers are Differentially Regulated between Synchrotron Microbeam Radiation Treatment and Synchrotron Broad-Beam Treatment by 48 Hours Postirradiation

Synchrotron microbeam radiation treatment (MRT) is a preclinical radiotherapy technique with considerable clinical promise, although some of the underlying radiobiology of MRT is still not well understood. In recently reported studies, it has been suggested that MRT elicits a different tumor immune profile compared to broad-beam treatment (BB). The aim of this study was to investigate the effects of synchrotron MRT and BB on eosinophil-associated gene pathways and eosinophil numbers within and around the tumor in the acute stage, 48 h postirradiation. Balb/C mice were inoculated with EMT6.5 mouse mammary tumors and irradiated with microbeam radiation (112 and 560 Gy) and broad-beam radiation (5 and 9 Gy) at equivalent doses determined from a previous in vitro study. After tumors were collected 24 and 48 h postirradiation, RNA was extracted and quantitative PCR performed to assess eosinophil-associated gene expression. Immunohistochemistry was performed to detect two known markers of eosinophils: eosinophil-associated ribonucleases (EARs) and eosinophil major basic protein (MBP). We identified five genes associated with eosinophil function and recruitment (Ear11, Ccl24, Ccl6, Ccl9 and Ccl11) and all of them, except Ccl11, were differentially regulated in synchrotron microbeam-irradiated tumors compared to broad-beam-irradiated tumors. However, immunohistochemical localization demonstrated no significant differences in the number of EAR- and MBP-positive eosinophils infiltrating the primary tumor after MRT compared to BB. In conclusion, our work demonstrates that the effects of MRT on eosinophil-related gene pathways are different from broad-beam radiation treatment at doses previously demonstrated to be equivalent in an in vitro study. However, a comparison of the microenvironments of tumors, which received MRT and BB, 48 h after exposure showed no difference between them with respect to eosinophil accumulation. These findings contribute to our understanding of the role of differential effects of MRT on the tumor immune response.

157. LYMPHATICS IN THE HUMAN PLACENTAL BED AND SURROUNDING THE SPIRAL ARTERIOLES DISAPPEAR DURING ENDOMETRIAL DECIDUALISATION

The mammalian placenta plays central roles in maternal tolerance of the semi-allogeneic fetus and fluid balance between maternal and fetal compartments. The lymphatics play a role in both immune function and fluid balance. The aim of this study was to describe the distribution of lymphatic vessels in human placental bed and decidua, with particular focus on the lymphatics that surround the remodelling spiral arteries during decidualisation and trophoblast invasion. Placental bed, non-placental bed and decidual biopsies were obtained from women undergoing elective pregnancy termination (6–18 weeks gestational age) and from women undergoing elective caesarean section at term. Double immunohistochemical labeling was performed on serial sections to identify lymphatic vessels in conjunction with blood vessels, smooth muscle, epithelial and trophoblast cells, or proliferating cells. Using representative photomicrographs, descriptive findings of the organisation of the human placental bed lymphatics were made. Lymphatic vessels positive for podoplanin (D2-40) were abundant in hypersecretory endometrium (lacking stromal decidualisation) at all stages of gestation. By contrast, the decidua was nearly always devoid of lymphatics. In some samples, structures that appeared to be regressing lymphatics were observed at the boundary between hypersecretory and decidual tissues. Lymphatic vessels were notably absent from the vicinity of spiral arteries that were surrounded by decidualised stromal cells. Lymphatic vessels in hypersecretory endometrium appeared larger and more elongated as gestation progressed. Proliferating lymphatic vascular endothelial cells were identified in both large vessels, and in streaks of D2-40 positive cells that could have been newly forming lymphatic vessels. In conclusion endometrial stromal cell decidualisation results in a loss of lymphatics, with this phenomenon being particularly apparent around the spiral arterioles; the functional consequences of this loss have yet to be elucidated.

527. EXTENSIVE LYMPHATIC REMODELLING OCCURS IN HUMAN PLACENTAL BED DURING THE FIRST 20 WEEKS OF PREGNANCY

The aim of this study was to describe the distribution of lymphatics in human placental bed from 6–20 weeks of pregnancy, with emphasis on the lymphatics surrounding the spiral arterioles as they undergo remodelling associated with trophoblast invasion. Placental bed biopsies were obtained following elective termination (n=41, 6–18 weeks gestation) and at term (n=5). Samples were routinely processed for serial sectioning at 3um to allow structural relationships to be compared in consecutive sections. Double immunohistochemistry protocols were used to identify lymphatic vessels in conjunction with one of: blood vessels, smooth muscle, epithelium and trophoblast, or proliferating cells. Immunostaining demonstrated that lymphatic vessels were present in abundance in the hypersecretory endometrium throughout all stages of gestation, and were prominent encircling spiral arterioles and adjacent to the endometrial glands. In contrast, the decidua was nearly always devoid of lymphatics, and in particular they were absent from the vicinity of spiral arterioles that were surrounded by decidual cells. In hypersecretory endometrium lymphatic vessel profiles varied greatly in architecture and size, and included focal accumulations of endothelial cells, through to fully formed lymphatic vessels. There was evidence of lymphatic vessel endothelial cell proliferation in all the different vessel types. The trophoblast appeared to have no overt influence on the structure or appearance of the lymphatic endothelium, with no evidence of incorporation into, or distortion of, the lymphatic vessel walls. Obvious increases were noted in the size of the lymphatic vessel profiles in hypersecretory endometrium as gestation progressed. The study provides the first detailed description of the placental bed lymphatics and their relationship to other endometrial structures during human pregnancy. We have shown that lymphatic vessels are absent from the decidua, apparently regressing as surrounding stromal cells decidualise. In contrast, the underlying hypersecretory endometrium contains abundant lymphatics which increase in size as pregnancy progresses.

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.

Immunohistochemical and ultrastructural characterization of the initial post-hatching development of bovine embryos

The problems of sustaining placenta formation in embryos produced by nuclear transfer have emphasized the need for basic knowledge about epiblast formation and gastrulation in bovine embryos. The aims of this study were to define stages of bovine post-hatching embryonic development and to analyse functional mechanisms of germ-layer formation. Embryos developed in vivo were collected after slaughter from superovulated cows on days 9, 11, 14 and 21 after insemination and processed for transmission electron microscopy (n = 26) or immunohistochemistry (n = 27) for potential germ-layer characterization (cytokeratin 8 for potential ectoderm; alpha-1-fetoprotein for potential endoderm; and vimentin for potential mesoderm). On day 9, the embryos were devoid of zona pellucida and presented a well-defined inner cell mass (ICM), which was covered by a thin layer of trophoblast cells (the Rauber's layer). Formation of the hypoblast from the inside of the ICM was ongoing. On day 11, the Rauber's layer was focally interrupted and adjacent underlying ICM cells formed tight junctions. The hypoblast, which formed a thin confluent cell layer, was separated from the ICM and the tropho-blast by intercellular matrix. The embryos were ovoid to tubular and displayed a confluent hypoblast on day 14. The epiblast was inserted into the trophoblast epithelium and tight junctions and desmosomes were present between adjacent epiblast cells as well as between peripheral epiblast and trophoblast cells. In some embryos, the epiblast was more or less covered by foldings of trophoblast in the process of forming the amniotic cavity. Cytokeratin 8 was localized to the trophoblast and the hypoblast underlying the epiblast; alpha-1-fetoprotein was localized to most hypoblast cells underlying the trophoblast; and vimentin was localized to most epiblast cells. On day 21, the smallest embryos displayed a primitive streak and formation of the neural groove, whereas the largest embryos presented a neural tube, up to 14 somites and allantois development. These embryos depicted the gradual formation of the endoderm, mesoderm and ectoderm as well as differentiation of paraxial, intermediate and lateral plate mesoderm. Cytokeratin 8 was localized to the trophoblast, the hypoblast and the surface and neural ectoderm; and alpha-1-fetoprotein was localized to the hypoblast, but not the definitive endoderm, the intensity increasing with development. Vimentin was initially localized to some, but not all, cells positioned particularly in the ventral region of the primitive streak, to presumptive definitive endoderm cells inserted into the hypoblast, and to mesoderm. In conclusion, within 2 weeks of hatching, bovine embryos complete formation of the hypoblast and the epiblast, establishment of the amniotic cavity, ingression of epiblast cells for primitive streak formation, involution of cells through the node and the streak for endoderm and mesoderm fomation, neurulation and differentiation of the mesoderm. The recruitment of cells from the epiblast to form the primitive streak as well as the endoderm and mesoderm is associated with expression of the intermediate filament vimentin.

Immunohistochemical and ultrastructural characterization of the initial post-hatching development of bovine embryos

The problems of sustaining placenta formation in embryos produced by nuclear transfer have emphasized the need for basic knowledge about epiblast formation and gastrulation in bovine embryos. The aims of this study were to define stages of bovine post-hatching embryonic development and to analyse functional mechanisms of germ-layer formation. Embryos developed in vivo were collected after slaughter from superovulated cows on days 9, 11, 14 and 21 after insemination and processed for transmission electron microscopy (n = 26) or immunohistochemistry (n = 27) for potential germ-layer characterization (cytokeratin 8 for potential ectoderm; alpha-1-fetoprotein for potential endoderm; and vimentin for potential mesoderm). On day 9, the embryos were devoid of zona pellucida and presented a well-defined inner cell mass (ICM), which was covered by a thin layer of trophoblast cells (the Rauber's layer). Formation of the hypoblast from the inside of the ICM was ongoing. On day 11, the Rauber's layer was focally interrupted and adjacent underlying ICM cells formed tight junctions. The hypoblast, which formed a thin confluent cell layer, was separated from the ICM and the tropho-blast by intercellular matrix. The embryos were ovoid to tubular and displayed a confluent hypoblast on day 14. The epiblast was inserted into the trophoblast epithelium and tight junctions and desmosomes were present between adjacent epiblast cells as well as between peripheral epiblast and trophoblast cells. In some embryos, the epiblast was more or less covered by foldings of trophoblast in the process of forming the amniotic cavity. Cytokeratin 8 was localized to the trophoblast and the hypoblast underlying the epiblast; alpha-1-fetoprotein was localized to most hypoblast cells underlying the trophoblast; and vimentin was localized to most epiblast cells. On day 21, the smallest embryos displayed a primitive streak and formation of the neural groove, whereas the largest embryos presented a neural tube, up to 14 somites and allantois development. These embryos depicted the gradual formation of the endoderm, mesoderm and ectoderm as well as differentiation of paraxial, intermediate and lateral plate mesoderm. Cytokeratin 8 was localized to the trophoblast, the hypoblast and the surface and neural ectoderm; and alpha-1-fetoprotein was localized to the hypoblast, but not the definitive endoderm, the intensity increasing with development. Vimentin was initially localized to some, but not all, cells positioned particularly in the ventral region of the primitive streak, to presumptive definitive endoderm cells inserted into the hypoblast, and to mesoderm. In conclusion, within 2 weeks of hatching, bovine embryos complete formation of the hypoblast and the epiblast, establishment of the amniotic cavity, ingression of epiblast cells for primitive streak formation, involution of cells through the node and the streak for endoderm and mesoderm fomation, neurulation and differentiation of the mesoderm. The recruitment of cells from the epiblast to form the primitive streak as well as the endoderm and mesoderm is associated with expression of the intermediate filament vimentin.

Myometrial microvascular endothelial cells express oxytocin receptor

OBJECTIVE

1. To establish whether microvascular endothelial cells from the human myometrium (MMECs) express oxytocin receptor, and to compare its expression levels relative to HUVECs. 2. To verify an up-regulation of oxytocin receptor expression in MMECs as a result of vascular endothelial growth factor (VEGF), which had been found in a previous study.

DESIGN

Laboratory scientific study.

SETTING

University department.

POPULATION OR SAMPLE

Myometrial biopsies from 12 hysterectomy specimens.

METHODS

MMECs and HUVECs were established in vitro. Immunohistochemistry of in vitro cultures was performed to investigate protein expression of the oxytocin receptor. Semi-quantitative RT-PCR and Northern blots were performed to examine the presence and relative abundance of oxytocin receptor mRNA in MMECs and HUVECs, and in both cell types with and without VEGF. Total RNA from oxytocin acetate (100 nmol/L) and vehicle stimulated endothelial cell cultures was used to examine gene expression differences on a 10.5K cDNA microarray.

MAIN OUTCOME MEASURES

Oxytocin receptor mRNA and protein; gene expression anlysis.

RESULTS

Oxytocin receptor mRNA and protein was present in MMECs. The level of expression was the same as for the HUVECs, but much less than the pregnant myometrium. No effect on gene expression could be demonstrated by gene expression microarray following 10 hours of oxytocin stimulation. Twenty-four hours of VEGF stimulation did not significantly alter oxytocin receptor mRNA expression in MMECs or HUVECs.

CONCLUSION

The myometrial microvasculature expresses oxytocin receptor. This finding means that oxytocin may exert some of its effects on the myometrial microvasculature. No evidence could be found for a transcriptional effect of oxytocin stimulation in this study, but further work on the role of the myometrial vessel oxytocin receptor is needed.

Bladder microvasculature in women with interstitial cystitis

PURPOSE

A cardinal cystoscopic finding in women with interstitial cystitis is mucosal small vessel hemorrhage or glomerulations after hydrodistention. We quantified and compared microvascular density and endothelial proliferation in the bladder biopsies of women with interstitial cystitis and a control group of women who were undergoing incontinence or prolapse surgery.

MATERIALS AND METHODS

We performed computer assisted image analysis and immunohistochemical studies to compare differences in the blood vessel count, and proportional area in the bladder suburothelium and deeper submucosa of bladder biopsies of 52 women, including 26 with interstitial cystitis. Routine light microscopy features were examined and correlated with microvascular density.

RESULTS

In the bladder biopsies of women with interstitial cystitis there was a lower blood vessel count (p = 0.01), and a lower proportion of the total image consisted of blood vessel wall (p = 0.03) in the suburothelium than in control biopsies. We noted no difference in the blood vessel count of the deeper submucosa or in the degree of endothelial cell proliferation. Suburothelial blood vessel differences correlated with the degree of histological change, such as edema, inflammatory infiltrate and vascular congestion.

CONCLUSIONS

We found decreased microvascular density in the suburothelium but not in the deeper submucosa in bladder biopsies of women with interstitial cystitis.