Biomedical subjects

D Stephen Charnock-Jones

Publications and source records attributed to D Stephen Charnock-Jones.

27 records · Page 2Linked to original sources

PubMed2003

Determination of the transcript profile of human endometrium.

The response of the human endometrium to the ovarian hormones, estrogen and progesterone, has been the focus of decades of research. In order to understand this critical aspect of endometrial physiology, we undertook a genome-wide analysis of transcript abundance and changes in transcript level between normal endometrium in the proliferative and secretory phases of the menstrual cycle. A high-density, oligonucleotide gene array, comprising 60 000 gene targets, was used to define the gene expression profile of proliferative and secretory phase endometrium. Results from the arrays were verified using real-time PCR. The expression levels of 149 transcripts differed significantly between the two phases of the cycle determined by stringent range limits (99.99%), calculated using local variance values. These transcripts include previously documented steroidally responsive genes (such as placental protein 14 and stromelysin-3) and novel transcripts not previously linked to either endometrial physiology or steroid regulation (such as intestinal trefoil factor and a number of expressed sequence tags). Examination of the 5' promoter regions of these genes identified many putative estrogen and progesterone receptor DNA binding domains, suggesting a direct response of these genes to the ovarian hormones.

Base Sequence↗

PubMed2003

Soluble vascular endothelial growth factor receptor 1 inhibits edema and epithelial proliferation induced by 17beta-estradiol in the mouse uterus.

The uterine response to 17beta-estradiol (E2) includes increased water retention, enhanced vascular permeability, DNA and RNA synthesis, and increased cellular mitosis. We have used the natural antagonist of vascular endothelial growth factor A (VEGF-A), sflt-1 (soluble form of flt-1), to determine whether the edematous and proliferative effects of E2 in the uterus are mediated by VEGF-A. Female BALB/c mice were ovariectomized and treated with E2 (10 micro g/kg) in the absence or presence of sflt-1 (0.8 and 4.0 mg/kg) for 24 h. E2 induced increases in uterine mass from 25.3 to 36.8 mg, in total cross-sectional uterine area from 771 to 1133 micro m(2), in cross-sectional endometrial area from 268 to 569 micro m(2), and in the mitotic index of lumenal epithelial cells from 0% to 53%. Antagonism with sflt-1 reduced the E2-induced increases in total uterine area to 779 micro m(2), endometrial area to 398 micro m(2) and the mitotic index of lumenal epithelial cells to 25%, but the E2-induced increase in uterine mass was not significantly reduced. From these data we conclude that the edematous response and proliferation of lumenal epithelial cells in the murine uterus are mediated in part through VEGF-A. These data suggest that sflt-1 could be a useful anti-VEGF-A agent and may be effective in modifying uterine biology.

Animals↗

PubMed2003

Antiangiogenic agents are effective inhibitors of endometriosis.

Endometriosis is a disease in which the lining of the uterus (endometrium), shed at the time of menstruation, becomes established at sites such as the peritoneum and ovaries. These explants develop a rich blood supply that enables them to survive and grow. We hypothesized that inhibitors of angiogenesis would prevent this growth by disrupting sensitive vessels supplying endometriotic lesions. Vessels sensitive to angiogenic antagonism have few associations with pericyte cells. The vessels supplying human endometriotic lesions were immunohistochemically characterized and found to be predominantly pericyte free. A model in which human endometrium is implanted into nude mice was used to test the effects of two antagonists of the angiogenic growth factor, vascular endothelial cell growth factor A. Soluble truncated receptor (flt-1; P = 0.002) and an affinity-purified antibody to human vascular endothelial cell growth factor A (P = 0.03) significantly inhibited the growth of nude mouse explants. Pericyte-free vessels were shown to supply endometrial lesions in nude mice and were disrupted in lesions taken from soluble flt-1-treated mice. In summary, antiangiogenic agents inhibited the growth of explants in an in vivo model of endometriosis by disrupting the vascular supply, and this effect is likely to apply to the human disease. These findings suggest that antiangiogenic agents may provide a novel therapeutic approach for the treatment of endometriosis.

Angiogenesis Inhibitors↗

PubMed2003

Expression of vascular endothelial growth factor (VEGF)-D and its receptor, VEGF receptor 3, as a prognostic factor in endometrial carcinoma.

PURPOSE: To evaluate the prognostic value of vascular endothelial growth factor (VEGF)-D and VEGF receptor (VEGFR)-3 in endometrial carcinoma. EXPERIMENTAL DESIGN: We assessed the levels of immunoreactivity for VEGF-D and VEGFR-3 in 71 endometrial carcinomas, 14 complex atypical endometrial hyperplasias, and 16 normal endometria by immunohistochemistry. RESULTS: VEGF-D was stained in both tumor cells and adjacent stromal cells. VEGFR-3 was stained in both tumor cells and adjacent endothelial cells. Immunoreactivity for VEGF-D in tumor cells and adjacent stromal cells became significantly stronger as lesions progressed from normal endometrium to advanced carcinoma. Similarly, immunoreactivity for VEGFR-3 in tumor cells and adjacent endothelial cells was significantly greater as lesions progressed from normal endometrium to advanced carcinoma. A strong correlation was found between high levels of VEGF-D immunoreactivity in carcinoma cells and VEGFR-3 in both carcinoma cells and adjacent endothelial cells. Similarly, high levels of VEGF-D immunoreactivity in stromal cells were significantly correlated with those of VEGFR-3 in both carcinoma cells and endothelial cells. High levels of VEGF-D in carcinoma cells and stromal cells, as well as those of VEGFR-3 in carcinoma cells and endothelial cells, were significantly related to myometrial invasion and lymph node metastasis. A strong correlation was found between poor survival and high levels of VEGF-D in both carcinoma cells and stromal cells and between poor survival and high levels of VEGFR-3 in carcinoma cells. Moreover, the high levels of VEGF-D in stromal cells and VEGFR-3 in carcinoma cells were independent prognostic factors in endometrial carcinoma. CONCLUSIONS: The presence of VEGF-D and VEGFR-3 in endometrial carcinoma may predict myometrial invasion and lymph node metastasis and may prospectively identify patients who are at increased risk for poor outcome. In addition, VEGF-D and VEGFR-3 may be promising targets for new therapeutic strategies in endometrial carcinoma.

Adult↗

PubMed2002

Hypoxia-reoxygenation: a potent inducer of apoptotic changes in the human placenta and possible etiological factor in preeclampsia.

Preeclampsia is a severe disorder of human pregnancy characterized by generalized activation of maternal endothelial cells. Oxidative stress of the placenta is considered a key intermediary step, precipitating deportation of apoptotic fragments into the maternal circulation, but the cause remains unknown. We hypothesize that intermittent placental perfusion, secondary to deficient trophoblast invasion of the endometrial arteries, leads to an ischemia-reperfusion-type insult. We therefore tested whether hypoxia-reoxygenation (H/R) in vitro stimulates apoptosis in human placental tissues compared with controls kept hypoxic or normoxic throughout. After H/R, release of cytochrome c from mitochondria was significantly increased and was associated with intense immunolabeling for active caspase 3 in the syncytiotrophoblast and fetal endothelial cells. There was also increased labeling of syncytiotrophoblastic nuclei for cleaved poly (ADP-ribose) polymerase (PARP), and higher cytosolic concentrations of cleaved PARP fragment were detected by Western blot. Syncytiotrophoblastic nuclei displayed increased chromatin condensation, and a significantly greater percentage was TUNEL positive. These changes were accompanied by increased lactate dehydrogenase release into the medium. Preadministration of the free radical scavenger, desferrioxamine, reduced cytochrome c release and the TUNEL-positive index, suggesting generation of hydroxyl radicals mediates these processes. By contrast, hypoxia alone caused a smaller increase in the TUNEL-positive index, and the majority of syncytiotrophoblastic nuclei displayed karyolysis, whereas normoxic controls remained euchromatic. We conclude that H/R stimulates apoptotic changes within the syncytiotrophoblast, whereas hypoxia principally induces necrosis. The quality of placental perfusion may therefore be a more important factor in the pathophysiology of preeclampsia than the absolute quantity.

Apoptosis↗

PubMed2002

VavCre transgenic mice: a tool for mutagenesis in hematopoietic and endothelial lineages.

Cre transgenic mice can be used to delete gene sequences flanked by loxP sites in specific somatic tissues. We have generated vavCre transgenic mice, which can be used to inactivate genes specifically in adult hematopoietic and endothelial cells. In these animals, a Cre transgene is expressed under control of murine vav gene regulatory elements. To assess their usefulness, vavCre transgenic mice were bred with R26R mice, which express a lacZ reporter gene only in cells where Cre-mediated recombination has occurred. VavCre/R26R double-heterozygous offspring were analyzed by beta-galactosidase histochemistry and flow cytometry. VavCre-mediated recombination occurred in most hematopoietic cells of all hematopoietic organs, including the hematopoietic progenitor-rich bone marrow. Recombination also occurred in most endothelial and germ cells, but only rarely in other cell types. The recombination in both hematopoietic and endothelial lineages may partly reflect their putative shared ontogeny and provides a unique tool for simultaneous pan-hematopoietic and endothelial mutagenesis.

Animals↗

PubMed2002

Soluble flt-1 and the angiopoietins in the development and regulation of placental vasculature.

One of the key roles of the placenta is to mediate exchange of oxygen, nutrients and waste products between the maternal and fetal circulations. While some nutrients are actively taken up, oxygen is passively transported (i.e. it moves down a simple concentration gradient). To ensure an adequate supply as gestation progresses, the vascular structures in the human placenta remodel to facilitate this transfer. Under conditions in which oxygen is limited, at high altitude for example, these adaptations become more pronounced. In placentae obtained from high altitude the mean diameter of vessels is increased and the number of perivascular cells (pericytes) is reduced. Pericytes play an important role in modulating endothelial cell function and in their absence the endothelial cells are sensitive to growth factor withdrawal. The vascular remodelling that occurs in normal pregnancy is in part mediated by soluble factors (some produced by pericytes) and the level of these may in turn be regulated by local oxygen tension. We have shown that the mRNAs encoding both angiopoietins are present in the placenta and both are regulated by local PO2. Ang-2 mRNA transcription is increased under reduced oxygen and the stability of Ang-1 mRNA is reduced under similar conditions. Thus the ratio of mRNAs encoding these antagonistic factors changes (in favour of Ang-2), in the placenta in response to a reduction in PO2. The adaptations seen in the placenta and the mechanism by which they are achieved may be generally applicable.

Adaptation, Physiological↗

PubMed2002

A longitudinal study of biochemical variables in women at risk of preeclampsia.

OBJECTIVE: The purpose of this study was to characterize gestational profiles of biochemical markers that are associated with preeclampsia in the blood of pregnant women in whom preeclampsia developed later and to compare these markers with the markers of women who were delivered of small-for-gestational-age infants without preeclampsia and with women who were at low risk for the development of preeclampsia. STUDY DESIGN: This was a prospective case control study. The subjects were women at risk of preeclampsia who were enrolled in the placebo arm of a clinical trial. Indices of antioxidant status, oxidative stress, placental and endothelial function, and serum lipid concentrations were evaluated from 20 weeks of gestation until delivery in 21 women in whom preeclampsia developed later, in 17 women without preeclampsia who were delivered of small-for-gestational-age infants, and in 27 women who were at low risk for the development of preeclampsia. RESULTS: Ascorbic acid was reduced early in preeclampsia and small-for-gestational-age pregnancies. Leptin, placenta growth factor, the plasminogen activator inhibitor (PAI-1)/PAI-2 ratio, and uric acid were predictive of the development of preeclampsia. CONCLUSION: Gestational profiles of several markers were abnormal in the group with preeclampsia, and some of the markers that may prove useful in the selective prediction of preeclampsia were identified.

Algorithms↗

PubMed2002

Vitamin C and E supplementation in women at risk of preeclampsia is associated with changes in indices of oxidative stress and placental function.

OBJECTIVE: We have previously reported a reduced incidence of preeclampsia in women who were at risk and were taking vitamin C (1000 mg/d) and vitamin E (400 IU/d) supplements. In this study, we determined whether supplementation in the same cohort was associated with an improvement in indices of placental dysfunction and oxidative stress toward values determined in women who were at low risk of preeclampsia. STUDY DESIGN: Seventy-nine women who were at high risk and who were taking vitamin supplements and 81 who were taking placebos were compared with 32 women who were at low risk and who were not taking supplements who were studied simultaneously. RESULTS: Indices of oxidative stress and placental function were abnormal in the placebo group. When the placebo group was compared with the women who were at low risk, ascorbic acid, plasminogen activator inhibitor-2, and placenta growth factor concentrations were decreased; and 8-epi-prostaglandin F(2alpha),leptin, and the plasminogen activator inhibitor-1/-2 ratio were increased. In the group that received vitamin supplements, ascorbic acid, 8-epi-prostaglandin F(2alpha), leptin, and plasminogen activator inhibitor-1/-2 values were similar to women who were at low risk. CONCLUSION: Antioxidant supplementation in women who were at risk of preeclampsia was associated with improvement in biochemical indices of the disease.

Adult↗