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Biomedical subjects

C J Lockwood

Publications and source records attributed to C J Lockwood.

At least 19 recordsLinked to original sources
PubMed2006

Regulation of chemokine production in response to pro-inflammatory cytokines in first trimester decidual cells.

OBJECTIVE: Chemokines initiate the immune response by controlling leukocyte migration and lymphocyte development. Macrophage infiltration of the decidua has been implicated in the genesis of recurrent miscarriage and preeclampsia. Therefore, we determined whether cultured human decidual cells produce monocyte/macrophage-recruiting chemokines in response to a potent pro-inflammatory cytokine, interleukin-1beta (IL-1beta), and whether decidual cell-conditioned medium contains monocyte- and macrophage-chemoattractant activity. METHODS: Leukocyte-free first trimester decidual cells were treated for 6h with estradiol (E(2)) and medroxyprogesterone acetate (MPA) to mimic the steroidal milieu of pregnancy, or E(2) and MPA and IL-1beta (1 ng/ml) to mimic inflamed decidua. Total RNA was used for cDNA synthesis. Biotinylated cRNAs were generated and chemically fragmented for hybridization on Affymetrix HG_U133 Plus 2.0 chips followed by fluorescence labeling and optical scanning. Raw data generated from Affymetrix GCOS 1.2 (GeneChip Operating Software) were analyzed by GeneSpring 7.2 software. Subsequently microarray results were validated by real time RT-PCR and Western blotting. A functional study of monocyte migration was carried out also using conditioned media from culture. RESULTS: Five chemokines responsible for monocyte/macrophage chemoattraction and activation, including C-C motif ligand 2 (CCL2), CCL5, C-X-C motif ligand 2 (CXCL2), CXCL3 and CXCL8, were markedly elevated from 29- to 975-fold after exposure to IL-1beta in cultured first trimester decidual cells. The results of real-time RT-PCR (up-regulation from 43- to 3069-fold) and Western blotting (up-regulation from 15- to 300-fold) confirmed the microarray findings. Monocyte migration was significantly induced by the conditioned medium from IL-1beta-treated decidual cells. CONCLUSIONS: Treatment of first trimester decidual cells with IL-1beta induces secretion of monocyte/macrophage recruiting-chemokines and promotes monocyte migration. Extrapolation of these in vitro results to the milieu of implantation site suggests a mechanism whereby IL-1beta could mediate excessive macrophage infiltration of the decidua.

Blotting, Western↗
PubMed2006

Long-term progestin-only contraceptives result in reduced endometrial blood flow and oxidative stress.

CONTEXT: Because of their safety and efficacy, long-term progestin-only contraceptives (LTPOCs) are well-suited for women with restricted access to health care. However, abnormal uterine bleeding (AUB) causes half of all users to discontinue therapy within 12 months. Endometria of LTPOC-treated patients display aberrant angiogenesis with abnormally enlarged, thin-walled, fragile blood vessels, inflammation, and focal hemorrhage. In this study, similar effects were observed with a new third-generation implantable LTPOC. OBJECTIVE: We hypothesized that LTPOC reduces uterine and endometrial blood flow, leading to hypoxia/reperfusion, which triggers the generation of reactive oxygen species. The latter induce aberrant angiogenesis, causing AUB. DESIGN: Endometrial perfusion was measured by laser-Doppler fluxmetry in women requesting LTPOCs. Endometrial biopsies were obtained for in vivo and in vitro experiments. SETTING: The study was conducted in the Yale University School of Medicine and Family-Planning Center in Western Australia. PATIENTS: Seven women 18 yr or older requesting implantable LTPOCs were recruited in Western Australia. INTERVENTION: Women received etonorgestrel implants. MAIN OUTCOME: LTPOC treatment resulted in reduced endometrial perfusion and increased endometrial oxidative damage. CONCLUSIONS: We propose that LTPOCs result in hypoxia reperfusion, which leads to aberrant angiogenesis resulting in AUB.

Adult↗
PubMed2005

Protein Z, protein S levels are lower in patients with thrombophilia and subsequent pregnancy complications.

OBJECTIVE: We posit that low levels of protein S (PS) and protein Z (PZ) contribute to adverse pregnancy outcome (APO). PATIENTS: We evaluated 103 women with subsequent normal pregnancy outcome (NPO), 106 women with APO, and 20 women with thrombophilia (TP). METHODS: We compared first trimester (1st TRI) PZ levels in 103 women with NPO, 106 women with APO, and in 20 women with TP. We compared plasma levels of PZ and free PS antigen during the second (2nd TRI) and third trimesters (3rd TRI) of pregnancy in 51 women with APO and 51 matched women with NPO. RESULTS: The mean 1st TRI PZ level was significantly lower among patients with APO, compared to pregnant controls (1.81 +/- 0.7 vs. 2.21 +/- 0.8 microg mL(-1), respectively, P < 0.001). Of patients with known TP, those with APO had a tendency for lower mean PZ levels compared to those TP women with NPO (1.5 +/- 0.6 vs. 2.3 +/- 0.9 microg mL(-1), respectively, P < 0.0631). There was a significant decrease in the PZ levels in patients with APO compared to NPO (2nd TRI 1.5 +/- 0.4 vs. 2.0 +/- 0.5 microg mL(-1), P < 0.0001; and 3rd TRI 1.6 +/- 0.5 vs. 1.9 +/- 0.5 microg mL(-1), P < 0.0002). Protein S levels were significantly lower in the 2nd and 3rd TRIs among patients with APO compared to patients with NPO (2nd TRI 34.4 +/- 11.8% vs. 38.9 +/- 10.3%, P < 0.05, respectively; and 3rd TRI 27.5 +/- 8.4 vs. 31.2 +/- 7.4, P < 0.025, respectively). CONCLUSIONS: We posit that decreased PZ and PS levels are additional risk factors for APO.

Adult↗
PubMed2005

Metalloproteinase expression by control and telomerase immortalized human endometrial endothelial cells.

Vascular endothelial cells play a critical role in the maintenance of endometrial homeostasis. Indeed many pathological conditions causing abnormal endometrial bleeding including progestin only contraception, hormone replacement therapy, endometrial polyps, myomas, hyperplasia and cancer are associated with aberrant angiogenesis. Critical to the process of angiogenesis is the breakdown of the surrounding tissues by matrix metalloproteases (MMPs). In addition to the cells surrounding the endometrial endothelial cells, the endothelial cells themselves produce their own panel of MMPs. We now characterize the specific MMPs that are expressed by endothelial cells derived from human endometrium. These include MMP-1, MMP-2 and MMP-10 but not MMP-3. In addition, in order to successfully carry out consistent, homogeneous and sufficient numbers of studies we investigated the in vitro expression of the MMPs with both freshly isolated, early passaged endometrial endothelial cells (HEECs) as well as with newly telomerase immortalized HEECs (T-HEECs). The latter were karyotypically normal and expressed classic endothelial cell endpoints such as tubulogenesis on matrigel and expression of the endothelial cell markers CD-31 (PECAM), von Willebrand's factor, and the Tie-2 receptors. The levels of MMP expression as well as that of the metalloprotease inhibitors TIMP-1 and TIMP-2 were similar in parent and immortalized endothelial cells.

Cell Line, Transformed↗
PubMed2005

Role of cytokines in preterm labor and birth.

Preterm birth (defined as delivery prior to 37 weeks' gestation) complicates 5-10% of all births. It is a major cause of perinatal mortality and morbidity. Approximately 20% of all preterm births are iatrogenic resulting from obstetric intervention for maternal and/or fetal indications. Of the remainder, 2/3 are spontaneous preterm labor with or without preterm premature rupture of the membranes (pPROM). Preterm labor is a syndrome rather than a diagnosis since the etiologies are varied. Risk factors include, among others, pPROM, cervical insufficiency, pathologic uterine distention (polyhydramnios, multiple gestation), uterine anomalies, intrauterine infection/inflammation, and social factors (stress, smoking, heavy work). The final common pathway appears to be activation of the inflammatory cascade. Bacterial colonization and/or inflammation of the choriodecidual interface induces production of pro-inflammatory cytokines that, in turn, lead to neutrophil activation and the synthesis and release of uterotonins such as prostaglandins (which cause uterine contractions) and metalloproteinases (that weaken fetal membranes and remodel cervical collagen). This monograph reviews the role of cytokines in the pathophysiology of preterm labor and delivery.

Adolescent↗
PubMed2004

Endometrial angiogenesis: from physiology to pathology.

Numerous factors have been implicated in angiogenesis. This article concentrates on the expression of the major angiogenic factors, namely, vascular endothelial growth factor (VEGF) and the angiopoietins in the human endometrium. Particular emphasis is placed on the expression of the angiopoietins and their physiological and pathological expression.

Adenocarcinoma↗
PubMed2004

Angiogenic factors and the endometrium following long term progestin only contraception.

Endometria from long term progestin only contraceptive-treated patients display abnormally enlarged blood vessels that are prone to bleeding as well as inflammation and possibly local diminution in blood flow. Such bleeding is also characterized by focal reductions in the expression of angiopoietin-1, a vessel stabilization and maturation agent, and excess production of the potent angiogenic agents, vascular endothelial growth factor and angiopoietin-2. In addition, tissue factor, the key initiator of hemostasis may play an angiogenic role either directly or via the activation of thrombin. This review article summarizes current findings related to the endometrial dysregulation of angiogenic/hemostatic agents following treatment with long term progestin only contraception. Studies in this area offer a promising avenue to alleviate abnormal uterine bleeding associated with this otherwise highly effective form of contraception

Angiogenesis Inducing Agents↗
PubMed2003

Intrauterine transfusion for rhesus alloimmunization elevates fetal beta2-microglobulin levels.

BACKGROUND: Intrauterine transfusions for rhesus alloimmunization leads to alterations in circulating T-cell populations. Given that elevations in circulating beta2-microglobulin are a marker of T-cell-mediated organ transplant rejection, we evaluated the effect of intrauterine transfusion on fetal beta2-microglobulin levels. METHODS: Umbilical venous samples were obtained immediately prior to initial transfusion in ten anemic fetuses and in 12 fetuses with prior transfusions. Samples were also obtained from 18 gestational age-matched non-anemic fetuses and eight healthy neonates. RESULTS: The median concentration of beta2-microglobulin was significantly higher in fetuses with prior transfusions compared with non-anemic controls. In non-anemic controls, and in transfused fetuses, beta2-microglobulin levels decreased throughout gestation (r = -0.69, p = 0.01; and r = -0.80, p = 0.01, respectively). Among anemic and transfused fetuses, beta2-microglobulin levels displayed a negative correlation with fetal hematocrit (r = -0.62, p < 0.05; and r = -0.58, p = 0.04, respectively). CONCLUSIONS: We conclude that intrauterine transfusion for fetal anemia is associated with increased beta2-microglobulin levels, suggesting immunomodulatory effects of intrauterine transfusion on host immune responses to donor leukocyte antigens.

Anemia↗
PubMed2003

Fetal and maternal plasma leptin levels during the second half of normal pregnancies and those with Down syndrome.

OBJECTIVE: To assess the correlation of fetal and maternal plasma leptin concentrations during the second half of uncomplicated, euploid pregnancies and to compare these values with those obtained from pregnancies with Down syndrome. METHODS: Paired maternal venous and fetal umbilical blood samples were obtained during cordocentesis in 36 uncomplicated, euploid pregnancies and nine pregnancies with Down syndrome fetuses. Concentrations of leptin were measured by sensitive radioimmunoassay. RESULTS: Among pregnancies with euploid fetuses, there was significant correlation between both fetal and maternal leptin levels and gestational age (r = 0.464, p = 0.005 and r = 0.629, p < 0.001, respectively). Fetal plasma leptin concentrations also correlated with maternal levels (r = 0.485, p = 0.003), but fetal levels were significantly lower than maternal values (mean 2.12 +/- 0.44 ng/ml vs. 17.79 +/- 5.48 ng/ml, respectively; p < 0.001). Down syndrome fetuses had significantly lower fetal plasma leptin levels than gestational age-matched control euploid fetuses (0.72 + 0.54 ng/ml vs. 2.12 + 0.44 ng/ml; p < 0.002). However, there was no difference in maternal leptin concentrations between euploid and Down syndrome pregnancies. CONCLUSION: In euploid pregnancies, fetal leptin levels were significantly lower than the corresponding maternal values but increased across gestation. Down syndrome was associated with significantly lower fetal leptin levels.

Cordocentesis↗
PubMed2003

Perinatal outcomes in monoamniotic gestations.

OBJECTIVE: A comprehensive review of monoamniotic twin gestations reported between 1990 and 2002 was performed to estimate current perinatal mortality and morbidity rates, as well as the predictive value of an antenatal diagnosis of cord entanglement for poor obstetric outcomes. METHOD: A Medline literature review using the search term 'monoamniotic' and limited to articles published in the English language between 1990 and 2002 was performed. RESULTS: A total of 133 continuing, non-conjoined twin monoamniotic pregnancies with delivery information were identified. Perinatal loss per 2-week interval was relatively constant at 2-4% from 15 to 32 weeks. However, of the 131 fetuses reaching 33 weeks, the percentage loss significantly increased to 11.0% at 33-35 weeks and 21.9% at 36-38 weeks compared to that at 30-32 weeks. Overall perinatal mortality was 23.3%. Of all losses, 61.2% involved both twins and 38.8% involved only one fetus. Cord entanglements were documented antenatally in 22.6% of reports. There was a statistically significant decrease in the average number of neonatal intensive care unit days for non-anomalous neonates (10.6 +/- 7.7 vs. 32.6 +/- 32.0), average gestational age at the time of delivery (30.4 +/- 7.6 vs. 32.6 +/- 4.1), as well as a decrease in the prevalence of total (8.3% vs. 27.7%) and non-anomalous (7.0% vs. 21.6%) perinatal mortality in pregnancies with an antenatal diagnosis of cord entanglement compared to those without the antenatal diagnosis of cord entanglement. The presence of fetal anomalies was associated with a 42.9% perinatal mortality rate. CONCLUSIONS: Contrary to previous reports, there is a significant increase in the incidence of perinatal loss beyond 32 weeks among monoamniotic twins, suggesting that delivery after corticosteroid therapy should be strongly considered at this gestational age.

Female↗
PubMed2002

Thrombin-enhanced matrix metalloproteinase-1 expression: a mechanism linking placental abruption with premature rupture of the membranes.

OBJECTIVE: Given the strong clinical association between the decidual hemorrhage of placental abruption and subsequent preterm premature rupture of the membranes, we assessed the effects of thrombin on the expression of the potent interstitial collagenase, matrix metalloproteinase-1 (MMP-1), in cultured endometrial stromal and decidual cells. STUDY DESIGN: Stromal cells derived from predecidualized cycling endometrium and decidual cells from term decidua were cultured in a defined medium containing estradiol, to mimic the hormonal milieu of the non-pregnant proliferative phase, or estradiol plus medroxyprogesterone acetate (MPA), to mimic the hormonal milieu of pregnancy, in the presence and absence of thrombin. Culture media were examined for MMP-1 protein levels and cell lysates were examined for steady-state MMP-1 mRNA levels. RESULTS: MPA strongly inhibited MMP-1 levels in endometrial stromal and term decidual cells. However, thrombin overcame this suppression, producing MMP-1 levels that were several-fold higher than control levels. CONCLUSION: Extrapolation of thrombin-enhanced MMP-1 expression in cultured endometrial stromal and decidual cells to the in vivo pregnant state provides an explanation for the strong association between placental abruption and preterm membrane rupture.

Abruptio Placentae↗
PubMed2001

Risk stratification and pathological mechanisms in preterm delivery.

The delivery of infants before 37 weeks gestation is a leading cause of perinatal mortality and morbidity in the United States. Traditional methods of predicting women at risk relying on obstetric history or premonitory symptoms (detected clinically or by tocodynamometry) are neither sensitive nor specific. Recent approaches to predicting preterm delivery have included sonographic measurement of cervical length and various biochemical assays. Although more sensitive than traditional methods, none of these alone exhibits sufficient accuracy to warrant widespread use. We contend that the failure of current approaches to predicting preterm delivery reflects an inadequate understanding of the underlying pathogenesis. Clinical and experimental evidence support the concept that most cases of preterm delivery reflect four pathogenic processes, which share a common final biological pathway leading to uterine contractions and cervical changes with or without premature rupture of membranes. These pathogeneses are: (1) activation of the maternal or fetal hypothalamic-pituitary-adrenal axis; (2) decidual-chorioamniotic or systemic inflammation; (3) decidual haemorrhage (i.e. abruption); and (4) pathological distention of the uterus. Our research seeks to combine the most useful biophysical and biochemical markers of such processes with optimal clinical and epidemiological predictors into a composite, easily applied risk tool. This integrated approach has the potential to identify at-risk asymptomatic patients with high sensitivity, specificity, and positive and negative predictive values, and also to ascertain underlying pathogenic processes that can lead to targeted therapy. To accomplish these goals, we employ logistic regression and artificial neural network models to assess and apply the appropriate weight to markers associated with each of the above pathogenic pathways, in addition to markers of the final common pathway leading to fetal membrane rupture, cervical extracellular matrix degradation, and myometrial activation. By combining these markers, we expect ultimately to produce a predictive model that is more robust than any existing method, and that identifies the relative contribution of each pathogenic process. Further analysis of this model using a neural network will enable us to identify asymptomatic patients destined to deliver preterm with high sensitivity, specificity, positive and negative predictive values, and to assess the relative contribution of each of the four distinct pathogeneses to this preterm delivery risk.

Adult↗
PubMed2001

Regulation of plasminogen activator inhibitor 1 expression by interaction of epidermal growth factor with progestin during decidualization of human endometrial stromal cells.

OBJECTIVE: During human pregnancy implantation, trophoblasts invade maternal blood vessels in a process that risks hemorrhage. Previous studies have demonstrated enhanced expression of type 1 plasminogen activator inhibitor, the primary inhibitor of fibrinolysis, during progestin-induced decidualization of estradiol-primed human endometrial stromal cells in vivo and in vitro. Decidual cell-expressed plasminogen activator inhibitor 1 is appropriately positioned to avert implantational hemorrhage. Because of the absence of estrogen or progesterone response elements from the plasminogen activator inhibitor 1 gene promoter, I posited that epidermal growth factor mediates these steroid effects and that expression of epidermal growth factor receptor in human endometrial stromal cells is under ovarian steroid control. STUDY DESIGN: Confluent human endometrial stromal cells were exposed to vehicle control or to either estradiol (10(-8) mol/L) or medroxyprogesterone acetate (10(-7) mol/L), or both, with or without growth factors. After 40 hours the cultures were analyzed for plasminogen activator inhibitor 1 protein and messenger ribonucleic acid expressions. Immunostaining for epidermal growth factor receptor was carried out in sections of cycling and gestational endometrial tissues. RESULTS: In the absence of steroids, epidermal growth factor did not alter plasminogen activator inhibitor 1 expression. In the absence of epidermal growth factor, estradiol and medroxyprogesterone acetate enhanced human endometrial stromal cell-secreted plasminogen activator inhibitor 1 protein levels 8-fold (n = 12; P <.001), whereas estradiol alone had no effect. Marked synergistic increases in plasminogen activator inhibitor 1 levels were elicited when epidermal growth factor was added with estradiol and medroxyprogesterone acetate (n = 12; 65-fold; P <.0001). Both transforming growth factor alpha and epidermal growth factor, which act through epidermal growth factor receptor, increased steady-state plasminogen activator inhibitor 1 messenger ribonucleic acid levels several-fold when added with estradiol and medroxyprogesterone acetate. In contrast, transforming growth factor beta, which does not activate epidermal growth factor receptor, did not elevate plasminogen activator inhibitor 1 messenger ribonucleic acid or protein levels whether added alone or with estradiol and medroxyprogesterone acetate. In correspondence with these in vitro observations, immunostaining for epidermal growth factor receptor was increased in human endometrial stromal cells undergoing decidualization in sections of secretory phase and first-trimester endometrial tissue. CONCLUSIONS: Taken together, these in vitro and in vivo results indicate that both epidermal growth factor and progesterone receptors are required for maximal plasminogen activator inhibitor 1 expression by human endometrial stromal cells.

Blotting, Northern↗
PubMed2001

Plasma levels of thrombin-antithrombin complexes predict preterm premature rupture of the fetal membranes.

OBJECTIVE: Decidual hemorrhage (abruption) is strongly associated with preterm premature rupture of fetal membranes (PPROM). Moreover, thrombin enhances decidual matrix metalloproteinase (MMP) expression, and MMP has been strongly linked to PPROM. The current study sought to determine whether increased thrombin activation, as assessed by circulating maternal plasma thrombin-antithrombin (TAT) complexes, predicted subsequent PPROM. STUDY DESIGN: We conducted a nested, case-control study of plasma TAT levels, measured by sensitive immunoassay, among 27 women with a singleton preterm birth preceded by PPROM and 54 matched, term controls. Receiver operating characteristic curve analysis was performed to identify the optimal TAT cut-off level predicting PPROM. RESULTS: Mean gestational age at delivery in cases was 33.3 weeks, compared to 39.7 weeks in controls (p < 0.001). Compared with controls, women with PPROM had increased median plasma TAT levels in both the second trimester (5.1 microg/l (range 2.2-26.3 microg/l) vs. 3.2 microg/l (range 1.3-7.3 microg/l); p = 0.001) and third trimester (7.0 microg/l (range 2.6-85.8 microg/dl) vs. 4.8 microg/l (range 1.7-15.4 microg/dl); p = 0.01). In the PPROM group, 16.0% of the women exhibited bleeding during the pregnancy, while the corresponding value among controls was 3.6% (p = 0.07). In the second trimester, the odds ratio for PPROM with a TAT level of > 3.9 microg/l was 6.0 (95% CI 1.67-21.1). This value predicted PPROM with a sensitivity of 88%, specificity of 68% and positive and negative predictive values of 82% and 97%, respectively. CONCLUSION: Second-trimester elevated plasma TAT concentrations are predictive of subsequent PPROM. These data provide further evidence that PPROM is associated with decidual thrombin activation.

Adult↗
PubMed2001

Decidual cell-expressed tissue factor maintains hemostasis in human endometrium.

We showed that decidualized stromal cells of luteal phase and pregnant human endometrium express tissue factor (TF), the primary initiator of hemostasis, thereby suggesting a mechanism by which perivascular decidual cells can mitigate the risk of hemorrhage during endovascular trophoblast invasion. Progestins enhanced TF mRNA and protein levels in monolayers of human endometrial stromal cells (HESCs), with estradiol (E2) + progestin, further enhancing TF levels despite a lack of response to E2 alone. This differential ovarian steroid response has been found for several decidualization markers. Further studies with cultured HESCs established that elevated TF levels are mediated by the progesterone receptor and are maintained for weeks in response to E2 plus progestin, thus simulating the chronic upregulation of TF levels observed in decidualized HESCs in vivo. Recent studies revealed that elevated TF expression during in vitro decidualization of HESCs involved both the EGFR and progesterone receptor. Thus, enhancement of TF mRNA and protein levels in the HESCs required co-incubation with a progestin (MPA) and an EGFR agonist such as EGF or TGF-alpha. In correspondence with co-elevation of EGFR and TF in decidualized HESCs in sections of luteal phase and pregnant endometrium, EGFR levels proved to be progestin-enhanced in the cultured HESCs. We established that progestin-enhanced TF expression in HESCs was trancriptionally regulated, then evaluated the relative roles of SP and EGR-1 sites on the TF promoter in regulating this expression. Transient transfections with a series of promoter constructs containing overlapping SP and EGR-1 sites and with constructs in which the EGR-1 and SP sites were systematically inactivated by site-directed mutagenesis established the dominance of SP sites in both basal and progestin-enhanced TF transcriptional activity. Additional experiments involving transient transfections with SPloverexpressing vectors and with a specific blocker of if Sp1 binding to its corresponding GC box specified the importance of the Sp1 transcription factor. These results were further validated by immunostaining, which revealed that the ratio of Sp1 to Sp3 increased during progestin-regulated decidualization of HESCs in vitro and in vivo. The absence of canonical estrogen and progesterone response elements from either the TF or Sp1 gene promoters suggests that the EGFR may help to mediate progestin-enhanced TF expression during decidualization of HESCs.

Animals↗