Antibody to Endogenous Cardiotonic Steroid Reverses Vascular Fibrosis and Restores Vasorelaxation in Chronic Kidney Disease.

Marinobufagenin (MBG) is implicated in chronic kidney disease, where it removes Fli1-induced inhibition of the collagen-1. We hypothesized that (i) in nephrectomized rats, aortic fibrosis develops due to elevated plasma MBG and inhibited Fli1, and (ii) that the antibody to MBG reduces collagen-1 and improves vasodilatation. A partial nephrectomy was performed in male Sprague-Dawley rats. Sham-operated animals comprised the control group. At 5 weeks following nephrectomy, rats were administered the vehicle (n = 8), or the anti-MBG antibody (n = 8). Isolated aortic rings were tested for their responsiveness to sodium nitroprusside following endothelin-1-induced constriction. In nephrectomized rats, there was an increase in the intensity of collagen staining in the aortic wall vs. the controls. In antibody-treated rats, the structure of bundles of collagen fibers had ordered organization. Western blots of the aorta had lower levels of Fli1 (arbitrary units, 1 ± 0.05 vs. 0.2 ± 0.01; p < 0.001) and greater collagen-1 (arbitrary units, 1 ± 0.01 vs. 9 ± 0.4; p < 0.001) vs. the control group. Administration of the MBG antibody to rats reversed the effect of the nephrectomy on Fli1 and collagen-1 proteins. Aortic rings pretreated with endothelin-1 exhibited 50% relaxation following the addition of sodium nitroprusside (EC50 = 0.28 µmol/L). The responsiveness of the aortic rings obtained from nephrectomized rats was markedly reduced (EC50 = 3.5 mol/L) compared to the control rings. Treatment of rats with the antibody restored vasorelaxation. Thus, the anti-MBG antibody counteracts the Fli1-collagen-1 system and reduces aortic fibrosis.

Canrenone Restores Vasorelaxation Impaired by Marinobufagenin in Human Preeclampsia.

Previous studies implicated cardiotonic steroids, including Na/K-ATPase inhibitor marinobufagenin (MBG), in the pathogenesis of preeclampsia (PE). Recently, we demonstrated that (i) MBG induces fibrosis in rat tissues via a mechanism involving Fli1, a negative regulator of collagen-1 synthesis, and (ii) MBG sensitive Na/K-ATPase inhibition is reversed by mineralocorticoid antagonists. We hypothesized that in human PE elevated MBG level is associated with the development of fibrosis of the umbilical arteries and that this fibrosis can be attenuated by canrenone. Fifteen patients with PE (mean BP = 118 ± 4 mmHg; 34 ± 2 years; 38 ± 0.3 weeks gest. age) and twelve gestational age-matched normal pregnant subjects (mean BP = 92 ± 2 mmHg; 34 ± 1 years; 39 ± 0.2 weeks gest. age) were enrolled in the study. PE was associated with a higher plasma MBG level, with a four-fold decrease in Fli1 level and a three-fold increase in collagen-1 level in the PE umbilical arteries vs. those from the normal subjects (p < 0.01). Isolated rings of umbilical arteries from the subjects with PE exhibited impaired responses to the relaxant effect of sodium nitroprusside vs. control vessels (EC50 = 141 nmol/L vs. EC50 = 0.9 nmol/L; p < 0.001). The effects of PE on Fli1 and collagen-1 were blocked by the in vitro treatment of umbilical arteries by 10 µmol/L canrenone. Similar results were obtained for umbilical arteries pretreated with MBG. These data demonstrate that elevated MBG level is implicated in the development of the fibrosis of umbilical arteries in PE, and that this could be blocked by mineralocorticoid antagonists.

Preeclampsia: Cardiotonic Steroids, Fibrosis, Fli1 and Hint to Carcinogenesis.

Despite prophylaxis and attempts to select a therapy, the frequency of preeclampsia does not decrease and it still takes the leading position in the structure of maternal mortality and morbidity worldwide. In this review, we present a new theory of the etiology and pathogenesis of preeclampsia that is based on the interaction of Na/K-ATPase and its endogenous ligands including marinobufagenin. The signaling pathway of marinobufagenin involves an inhibition of transcriptional factor Fli1, a negative regulator of collagen synthesis, followed by the deposition of collagen in the vascular tissues and altered vascular functions. Moreover, in vitro and in vivo neutralization of marinobufagenin is associated with the restoration of Fli1. The inverse relationship between marinobufagenin and Fli1 opens new possibilities in the treatment of cancer; as Fli1 is a proto-oncogene, a hypothesis on the suppression of Fli1 by cardiotonic steroids as a potential anti-tumor therapeutic strategy is discussed as well. We propose a novel therapy of preeclampsia that is based on immunoneutralization of the marinobufagenin by monoclonal antibodies, which is capable of impairing marinobufagenin-Na/K-ATPase interactions.

Robotic-Assisted Laparoscopic Abdominal Cerclage Placement During Pregnancy.

STUDY OBJECTIVE: The objective of this study is to report our center's series of robotic-assisted laparoscopic abdominal cerclage (RALAC) placement during pregnancy. DESIGN: Descriptive study (Canadian Task Force classification III). SETTING: Single academic institution. PATIENTS: Patients undergoing RALAC placement during pregnancy. INTERVENTIONS: Eleven patients underwent RALAC. MEASUREMENTS AND MAIN RESULTS: Nine out of 11 (81.8%) primary RALAC procedures resulted in a viable live-born neonate; 8 (72.7%) were born at >34 weeks of gestation. Three patients (27.3%) had preterm premature rupture of membranes on postoperative day one, 2 of whom subsequently underwent a dilation and curettage, and 1 patient carried the pregnancy to 29 weeks and delivered a live-born neonate. Four patients had subsequent pregnancies after placement of a RALAC in the antepartum period, all of whom carried successfully beyond 36 weeks, for a total of 16 pregnancies. Fourteen pregnancies (87.5%) resulted in a live birth, and 13 pregnancies (81.3%) were delivered beyond 34 weeks. CONCLUSION: RALAC is a minimally invasive procedure with an acceptable risk profile and comparable efficacy to traditional open abdominal cerclage. RALAC may be considered an acceptable alternative to open abdominal cerclage in pregnancy, and may be a particularly favorable option in certain settings.

Antibody to Marinobufagenin Reverses Placenta-Induced Fibrosis of Umbilical Arteries in Preeclampsia.

BACKGROUND: Previous studies implicated cardiotonic steroids, including Na/K-ATPase inhibitor marinobufagenin (MBG), in the pathogenesis of preeclampsia (PE). Immunoneutralization of heightened MBG by Digibind, a digoxin antibody, reduces blood pressure (BP) in patients with PE, and anti-MBG monoclonal antibody lessens BP in a rat model of PE. Recently, we demonstrated that MBG induces fibrosis in cardiovascular tissues via a mechanism involving inhibition of Fli-1, a nuclear transcription factor and a negative regulator of collagen-1 synthesis. OBJECTIVES AND METHODS: We hypothesized that in PE, elevated placental MBG levels are associated with development of fibrosis in umbilical arteries. Eleven patients with PE (mean BP 124 ± 4 mmHg; age 29 ± 2 years; 39 weeks gest. age) and 10 gestational age-matched normal pregnant subjects (mean BP 92 ± 2 mmHg; controls) were enrolled in the clinical study. RESULTS: PE was associated with a higher placental (0.04 ± 0.01 vs. 0.49 ± 0.11 pmol/g; p < 0.01) and plasma MBG (0.5 ± 0.1 vs. 1.6 ± 0.5 nmol/L; p < 0.01), lower Na/K-ATPase activity in erythrocytes (2.7 ± 0.2 vs. 1.5 ± 0.2 µmol Pi/mL/hr; p < 0.01), 9-fold decrease of Fli-1 level and 2.5-fold increase of collagen-1 in placentae (p < 0.01) vs. control. Incubation of umbilical arteries from control patients with 1 nmol/L MBG was associated with four-fold decrease in Fli-1 level and two-fold increase in collagen-1 level vs. those incubated with placebo (p < 0.01), i.e., physiological concentration of MBG mimicked effect of PE in vitro. Collagen-1 abundance in umbilical arteries from PE patients was 4-fold higher than in control arteries, and this PE-associated fibrosis was reversed by monoclonal anti-MBG antibody ex vivo. CONCLUSION: These results demonstrate that elevated placental MBG level is implicated in the development of fibrosis of the placenta and umbilical arteries in PE.

Assessment of a cervicometer compared to transvaginal ultrasound in identifying women with a short cervical length: a multicenter study.

BACKGROUND: Preterm birth remains a major cause of neonatal morbidity and mortality worldwide. Short cervical length (CL) as measured by transvaginal ultrasound (TVU) in the second trimester represents the single most predictive risk factor for spontaneous preterm birth. Previous studies have addressed, in part, the limitations of TVU availability by utilizing a cervicometer to screen patients for short cervix, identifying those patients who may not benefit from TVU CL screening. In view of the prior studies indicating that a cervicometer measurement may have a high negative predictive value (NPV) for a sonographically short cervix, we sought to identify the ideal cervicometer threshold value in a prospective, multicenter study. OBJECTIVE: The primary objective was to determine the cervicometer CL measurement threshold that provides a high NPV for the identification of patients who are highly unlikely to have a TVU CL measurement ≤20 and ≤25 mm and, therefore, may forego TVU. STUDY DESIGN: This prospective study, executed in 5 US centers, included 401 women ≥18 years of age who provided written informed consent to undergo CL measurement in the mid trimester. All women underwent both cervicometer- and TVU-measured CLs by individuals blinded to results of the other measurement. Both measurements were performed at 17-23 weeks' gestation (visit 1) and repeated at 24-29 weeks' gestation (visit 2). All TVU measurement images were reviewed by a central reader. Test characteristics and receiver operating characteristic curves were created to determine and confirm the optimal cervicometer CL threshold, maximizing the NPV. RESULTS: In all, 358 subjects were evaluable at visit 1 and 267 at visit 2. At visit 1, the average TVU CL was 38.7 ± 7.6 mm and the average cervicometer CL was 30.3 ± 8.8 mm. Similar measurements were seen at visit 2. Receiver operating characteristic curves were utilized to graphically identify a cervicometer CL threshold of 30 mm that maximized sensitivity while minimizing the false-positive rate. The 30-mm cervicometer CL threshold provided a 98-100% NPV and 0.0 negative likelihood ratio for identification of women who have a low likelihood to have a sonographic short cervix (ie, transvaginal CL ≤20 mm or ≤25 mm). The 17-23 weeks' gestation 30-mm cervicometer CL threshold has 100% sensitivity, 45-46% specificity, and 1.8 and 0.0 positive and negative likelihood ratios to predict sonographic CL ≤20 and ≤25 mm. CONCLUSION: Cervicometer CL screening successfully identifies women at low risk for short transvaginal CL. Use of a 30-mm threshold by cervicometer CL measurement confers a 98-100% NPV, with high sensitivity and moderate specificity to predict a TVU short CL. Cervicometer measurement of CL may permit almost 50% of women to avoid TVU.

Expectant management of mild preeclampsia versus superimposed preeclampsia up to 37 weeks.

OBJECTIVE: We sought to compare maternal and neonatal outcomes of expectantly managed pregnancies complicated by chronic hypertension with superimposed preeclampsia vs mild preeclampsia up to 37 weeks of gestation. STUDY DESIGN: This was a multicenter retrospective cohort study of all pregnancies complicated by chronic hypertension with superimposed preeclampsia or mild preeclampsia expectantly managed in the hospital from January 2008 through December 2011. The primary outcomes, adverse maternal and neonatal composite morbidities, were compared between these 2 groups. Frequency differences of maternal adverse outcomes were stratified by gestational age at delivery of <34 and 34-36(6/7) weeks of gestation. RESULTS: We found no significant differences in rates of neonatal composite morbidity or latency periods between women with superimposed preeclampsia and mild preeclampsia. Adverse neonatal outcomes were significantly higher at <34 compared to 34-36(6/7) weeks of gestation (97-98% vs 48-50%) in both cohorts. Maternal adverse composite outcome occurred more frequently in women with superimposed preeclampsia compared to mild preeclampsia (15% vs 5%; P = .003; relative risk, 3.0; 95% confidence interval, 1.45-6.29). CONCLUSION: Women with superimposed preeclampsia have similar neonatal outcomes but more maternal complications than women with preeclampsia without severe features who are expectantly managed <37 weeks.

Initial experience with a dual-balloon catheter for the management of postpartum hemorrhage.

OBJECTIVE: When uterotonics fail to cause sustained uterine contractions and satisfactory control of hemorrhage after delivery, tamponade of the uterus can be effective in decreasing hemorrhage secondary to uterine atony. STUDY DESIGN: These data are from a postmarketing surveillance study of a novel dual-balloon catheter tamponade device, the Belfort-Dildy Obstetrical Tamponade System (ebb). RESULTS: A total of 57 women were enrolled: 55 women had the diagnosis of postpartum hemorrhage, and 51 women had uterine balloon placement within the uterine cavity. This study reports the outcomes in the 51 women who had uterine balloon placement within the uterine cavity for treatment of postpartum hemorrhage, as defined by the "Instructions for Use." We further assessed 4 subgroups: uterine atony only (n = 28 women), placentation abnormalities (n = 8 women), both uterine atony and placentation abnormalities (n = 9 women), and neither uterine atony nor placentation abnormalities (n = 6 women). The median (range) time interval between delivery and balloon placement was 2.2 hours (0.3-210 hours) for the entire cohort (n = 51 women) and 1.3 hours (0.5-7.0 hours) for the uterine atony only group (n = 28 women). Bleeding decreased in 22/51 of cases (43%), stopped in 28/51 of cases (55%), thus decreased or stopped in 50/51 of the cases (98%) after balloon placement. Nearly one-half (23/51) of all women required uterine balloon volumes of >500 mL to control bleeding. CONCLUSION: We conclude that uterine/vaginal balloon tamponade is very useful in the management of postpartum hemorrhage because of uterine atony and abnormal placentation.

Digoxin antibody fragment, antigen binding (Fab), treatment of preeclampsia in women with endogenous digitalis-like factor: a secondary analysis of the DEEP Trial.

OBJECTIVE: Endogenous digitalis-like factors (EDLFs) are elevated in women with preeclampsia, and the use of an anti-digoxin antibody Fab (DIF) in women with preeclampsia who were remote from term reduced maternal blood pressure and preserved renal function. The objective was to determine whether DIF treatment in women with severe preeclampsia in association with positive EDLFs in maternal serum improves maternal-perinatal outcomes. STUDY DESIGN: This was a planned secondary analysis from a randomized, placebo-controlled, double-blind study of DIF in women with severe preeclampsia with positive EDLF status that was managed expectantly between 23 weeks 5 days and 34 weeks' gestation (19 women received placebo, and 17 women received DIF). Primary outcome variables were a change in creatinine clearance and the use of antihypertensives. Secondary outcomes were maternal and perinatal complications. RESULTS: Women with positive EDLFs who received DIF had an attenuated decline in creatinine clearance from baseline compared with placebo (-4.5 ± 12.9 vs -53.2 ± 12.6 mL/min; P = .005). In this same group, the use of antihypertensives (the other primary outcome) was lower but not significantly so (41% vs 63%; P = .12). However, women who were treated with DIF had a lower rate of pulmonary edema (1/17 vs 6/19 women; P = .035) and lower rates of neonatal intraventricular hemorrhage (DIF: 0/17 women vs placebo: 5/19 women; P = .015). CONCLUSION: In women with severe preeclampsia who were remote from term who were EDLF positive, the use of DIF was associated with improved maternal and neonatal outcome. These findings suggest the need for a large multicenter trial that would evaluate the benefits of DIF in the treatment of women with severe preeclampsia who are remote from term and with positive EDLF status.

Directional Sensors for Recording Uterine EMG During Pregnancy.

Multichannel uterine electromyography (uEMG) during pregnancy is traditionally performed with electrocardiography (ECG) sensors. Similar signals are often observed in two or more channels, suggesting the ECG sensors report activities originating from the same location on the uterus. To improve signal source localization, we designed a directional sensor or "Area Sensor". Here we compare Area Sensors with ECG sensors for source localization. Subjects were ≥ 38 wks experiencing regular contractions. 6 Area Sensors (n = 8) or 6 to 7 ECG sensors (n = 7) were used to record multichannel uEMG for 60 min. For each sensor type, the similarity of signals observed in pairs of channels during contractions was assessed by quantifying channel crosstalk. Since crosstalk depends on the separation between sensors, analyses were performed within distance groups: A 9-12 cm; B 13-16 cm; C 17-20 cm; D 21-24 cm; E ≥ 25 cm. For ECG sensors, crosstalk was 67.9 ± 14.4% in group A, decreasing to 27.8 ± 17.5% in group E. For Area Sensors, crosstalk was 24.6 ± 18.6% in Group A, decreasing to 12.5 ± 13.8% in group E. Area Sensors showed less crosstalk than ECG sensors in distance groups A, B, C and D, with all p < 0.002. Compared with ECG sensors, Area Sensors are more directional and report uterine activity from a smaller area of the uterine wall. Using 6 Area Sensors separated by at least 17 cm provides acceptably independent multichannel recording. This introduces the possibility of non-invasively evaluating uterine synchronization and the strength of individual uterine contractions in real time.

Labor induction with intravaginal misoprostol compared with the dinoprostone vaginal insert: a systematic review and metaanalysis.

OBJECTIVE: The purpose of this study was to review randomized trials that compared the efficacy of the dinoprostone 10-mg controlled-release vaginal insert with that of vaginally administered misoprostol tablets in cervical ripening and labor induction. STUDY DESIGN: Electronic databases were used to identify randomized clinical trials that compared dinoprostone with misoprostol. Estimates of the relative risk for individual studies and risk difference from dichotomous outcomes with the use of random and fixed-effects models were calculated. RESULTS: Women who received misoprostol had a higher incidence of vaginal delivery within 12 and 24 hours of prostaglandin application, compared with dinoprostone. Both modalities had similar incidences of cesarean delivery, uterine hyperstimulation, and fetal tachysystole. There was an increased need for oxytocin augmentation in the dinoprostone group. No significant difference in neonatal outcomes was noted between the 2 groups. CONCLUSION: Vaginally administered misoprostol was more effective than the dinoprostone vaginal insert for cervical ripening and labor induction. The safety profiles of both drugs were similar.

Digoxin immune fab treatment for severe preeclampsia.

We evaluated the efficacy, safety, and biological mechanisms of digoxin immune Fab (DIF) treatment of severe preeclampsia. Fifty-one severe preeclamptic patients were randomized in double-blind fashion to DIF ( N = 24) or placebo ( N = 27) for 48 hours. Primary outcomes were change in creatinine clearance (CrCl) at 24 to 48 hours and antihypertensive drug use. Serum sodium pump inhibition, a sequela of endogenous digitalis-like factors (EDLF), was also assessed. CrCl in DIF subjects was essentially unchanged from baseline versus a decrease with placebo (-3 +/- 10 and -34 +/- 10 mL/min, respectively, P = 0.02). Antihypertensive use was similar between treatments (46 and 52%, respectively, P = 0.7). Serum sodium pump inhibition was decreased with DIF compared with placebo at 24 hours after treatment initiation (least squares mean difference, 19 percentage points, P = 0.03). DIF appeared to be well tolerated. These results suggest DIF prevents a decline in renal function in severe preeclampsia by neutralizing EDLF. Sodium pump inhibition was significantly improved. Further research is warranted.

Antibody against Na/K-ATPase Inhibitor Lowers Blood Pressure and Increases Vascular Fli1 in Experimental Preeclampsia.

BACKGROUND: Previous studies implicated cardiotonic steroids, including Na/K-ATPase inhibitor marinobufagenin (MBG), in the pathogenesis of preeclampsia (PE). We demonstrated that MBG induces fibrosis via mechanism involving inhibition of Fli1, a nuclear transcription factor and a negative regulator of collagen-1 synthesis. We hypothesized that PE blockade of increased MBG with antibody would lessen the fibrosis of umbilical arteries and lower the blood pressure in rats with PE. METHODS: We tested 36 pregnant Sprague-Dawley rats in which 12 were made hypertensive by 1.8% Na supplementation (days 6-19 of gestation), 12 pregnant rats served controls. At day 19, PE rats received one intraperitoneal injection of polyclonal anti-MBG-4 antibody (0.5 ug/ml) for 4 hours. RESULTS: PE was associated with higher blood pressure (117 ± 2 vs. 107 ± 2 mm Hg; P < 0.01), plasma MBG levels (1.54 ± 0.34 vs. 0.49 ± 0.11 nmol/L; P < 0.01), protein excretion (26 vs. 12 mg/24 hours), sFlt-1 (3-fold), decrease in Fli1 (7-fold) and increase in collagen-1 in aorta (4-fold) vs. control rats (all P < 0.01). In 12 rats treated with polyclonal anti-MBG-4 antibody blood pressure dropped (93 ± 3 mm Hg) and Fli1 was decreased much less (2-fold; P < 0.01 vs. nontreated rats). CONCLUSIONS: These results demonstrate that in experimental PE elevated MBG level is implicated in umbilical fibrosis via suppression of Fli1.

Endogenous Bufadienolides, Fibrosis and Preeclampsia.

Frequency of preeclampsia has no tendency to decrease, and it still takes the leading position in the structure of maternal mortality and morbidity worldwide. In this review, we present the "fibrotic concept" of the etiology and pathogenesis of preeclampsia which involves system consisting of Na/K-ATPase and its endogenous ligands including marinobufagenin. New therapy of preeclampsia includes modulation of the Na/K-ATPase system by immunoneutralization of the marinobufagenin and use of mineralocorticoid antagonists which are capable to impair marinobufagenin-Na/K-ATPase interactions.

Robotic-assisted laparoscopic placement of transabdominal cerclage during pregnancy.

Cervical incompetence treated with transabdominal cerclage can carry significant morbidity with the need for sequential laparotomies and necessitating prolonged postoperative recovery. Laparoscopic transabdominal cerclage placement has been described but has significant limitations with only two-dimensional depth perception and limited dexterity. Robotic-assisted laparoscopic surgery (RALS) is rapidly gaining acceptance in gynecologic surgery. RALS has reportedly been used for placement of an interval transabdominal cerclage. We report the first two cases where the da Vinci robot was used during pregnancy for placement of abdominal cerclage. Two women were successfully treated with robotic-assisted laparoscopic placement of transabdominal cerclage in pregnancy. Robotic-assisted laparoscopic transabdominal cerclage placement is less invasive and is effective not only as an interval procedure but also during pregnancy, offering the patient an alternative to the traditional laparotomy with quicker recovery time.

Digoxin immune fab protects endothelial cells from ouabain-induced barrier injury.

PROBLEM Endogenous digitalis-like factors (EDLF) inhibit sodium pump Na(+) /K(+) ATPase activity, and maternal EDLF levels are elevated in preeclampsia (PE). This study determined whether digoxin immune Fab (DIF) could protect endothelial cells (ECs) from EDLF-induced endothelial barrier dysfunction. METHOD OF STUDY ECs were treated with escalating doses of ouabain (a known EDLF) in the presence or absence of DIF. EC barrier integrity was examined by junction protein VE-cadherin and occludin expressions. EC permeability was determined by horseradish-peroxidase (HRP) leakage and transendothelial electrical resistance (TEER). RESULTS EC junction protein VE-cadherin distribution was disrupted in cells treated with ouabain. DIF, but not control IgG Fab fragment, blocked ouabain-induced decreases in VE-cadherin and occludin expressions and prevented ouabain-induced HRP leakage and TEER changes. CONCLUSION DIF protects ECs from ouabain-induced barrier injury, providing evidence of beneficial effects of DIF on EC function and supporting that Na(+) /K(+) ATPase might be a therapeutic target to ameliorate endothelial dysfunction.

Increasing evidence for and regulation of a human placental endogenous digitalis-like factor.

Endogenous digitalis-like factors (EDLFs) appear to be hypertensiogenic and increased in the serum and placenta of women with preeclampsia (PE), a complication of pregnancy. Digibind, an anti-digoxin antibody Fab fragment, reverses in vitro effects of EDLF and in vivo features of PE. We used Digibind in a radioimmunoassay to measure EDLF and compared this to a bio-functional assay of EDLF with good agreement. These methods confirmed that human placenta was a source of EDLF, synthesizing and releasing EDLF into the media of cultured human placental tissue. Ketoconazole, a steroid synthesis inhibitor, and 17-OH progesterone, a possible substrate of steroid synthesis, were shown to inhibit or increase EDLF release respectively, suggesting overlap of synthetic pathways. Abnormalities of PE such as placental hypoxia, increased reactive oxygen species and increased pro-inflammatory cytokines were demonstrated to increase placental EDLF release. These findings strongly support placental production of EDLF with increased release due to features of PE.

DigiFab interacts with endogenous cardiotonic steroids and reverses preeclampsia-induced Na/K-ATPase inhibition.

Elevated levels of endogenous Na/K-ATPase (NKA) inhibitors, cardiotonic steroids (CTSs) including marinobufagenin (MBG), contribute to pathogenesis of preeclampsia (PE) and represent a target for immunoneutralization by Digibind (Ovine Digoxin Immune Antibody, Glaxo-Smith Kline). Because Digibind is no longer commercially available, we studied whether DigiFab (BTG International Ltd, UK) can substitute Digibind for immunoneutralization of CTS in patients with PE. We compared DigiFab, Digibind, and anti-MBG monoclonal antibody (mAb) with respect to their ability to interact with CTS in PE plasma and to restore NKA activity in erythrocytes from patients with PE. Using immunoassays based on DigiFab, Digibind, and anti-MBG mAb, we studied the elution profile of CTS following high-performance liquid chromatography (HPLC) fractionation of PE plasma. Totally, 7 patients with mild PE (28 ± 2 years; gestational age, 39 ± 0.5 weeks; blood pressure 156 ± 5/94 ± 2 mm Hg) and 6 normotensive pregnant participants (28 ± 1 years; gestational age, 39 ± 0.4 weeks; blood pressure 111 ± 2/73 ± 2 mm Hg) were enrolled. Preeclampsia was associated with a substantial inhibition of erythrocyte NKA (1.47 ± 0.17 vs 2.65 ± 0.16 µmol Pi/mL per h in control group, P < .001). Ex vivo, at 10 µg/mL concentration, which is consistent with the clinical dosing of Digibind administered previously in PE, DigiFab and Digibind as well as anti-MBG mAb (0.5 µg/mL) restored erythrocyte NKA activity. Following HPLC fractionation of pooled PE and control plasma, PE-associated increase in CTS material was detected by Digibind (176 vs 75 pmoles), DigiFab (221 vs 70 pmoles), and anti-MBG mAb (1056 vs 421 pmoles). Therefore, because DigiFab interacts with CTS from PE plasma and reverses PE-induced NKA inhibition, it can substitute Digibind for immunoneutralization of CTS in patients with PE.

Environmental toxicant exposure during pregnancy.

UNLABELLED: This literature review is meant to serve as a brief reference for acute and chronic poisonings in pregnant women, specifically involving environmental toxicants commonly present in the home or workplace. These scenarios are familiar to primary care providers but cause great confusion for practitioners and anxiety in the pregnant patient. Herein, we review metals and metalloids, organic solvents, disinfectant byproducts, pesticides, plasticizers, and multiple air pollutants. Reviews of specific studies involving these toxicants are provided to assist practitioners in providing information to patients regarding potential sources, mechanism of action, current laboratory and epidemiological studies, and possible treatments. Literature-based associations with specific toxicants and various pregnancy outcomes are also outlined. Finally, a contact list of important federal and state toxicology support services is provided. TARGET AUDIENCE: Obstetricians & Gynecologists. LEARNING OBJECTIVES: After completing this CME activity, physicians should be better able to assess both acute and chronic consequences of various environmental toxic exposures in pregnancy; to evaluate possible pregnancy related specific events surrounding environmental pollutants; and to identify common exposure routes and implement therapeutic interventions where appropriate.

Digibind reverses inhibition of cellular rb+ uptake caused by endogenous sodium pump inhibitors present in serum and placenta of women with preeclampsia.

INTRODUCTION: Mechanisms mediating preeclampsia (PE) are unclear. Endogenous digitalis-like factors (EDLFs) are sodium pump (SP) inhibitors implicated in essential hypertension, but not fully explored in PE. This study asks whether EDLFs are present and increased in PE and considers their source. METHODS: EDLF in sera and placentas from third trimester women with uncomplicated pregnancies or PE was assessed by a Rb(+) uptake assay. A digoxin antibody Fab fragment (Digibind) known to inactivate EDLFs was also used to assess EDLFs. RESULTS: PE serum caused significantly more SP inhibition than serum from uncomplicated pregnancies. This inhibition was concentration-dependent and reversed by Digibind. Serum from uncomplicated pregnancies showed no concentration-dependence or reversal with Digibind. Placental homogenates from control women showed little SP inhibition, but homogenates from PE women showed marked SP inhibition reversed by Digibind. CONCLUSION: These studies evidence EDLF in PE serum. Additionally, PE placentas have high EDLF and may represent a source.