Encapsulating peritoneal sclerosis (EPS) is a devastating complication of peritoneal dialysis (PD), characterized by marked inflammation and severe fibrosis of the peritoneum, and associated with high morbidity and mortality. EPS can occur years after termination of PD and, in severe cases, leads to intestinal obstruction and ileus requiring surgical intervention. Despite ongoing research, the pathogenesis of EPS remains unclear. We performed a global transcriptome analysis of peritoneal tissue specimens from EPS patients, PD patients without EPS, and uremic patients without history of PD or EPS (Uremic). Unsupervised and supervised bioinformatics analysis revealed distinct transcriptional patterns that discriminated these three clinical groups. The analysis identified a signature of 219 genes expressed differentially in EPS as compared to PD and Uremic groups. Canonical pathway analysis of differentially expressed genes showed enrichment in several pathways, including antigen presentation, dendritic cell maturation, B cell development, chemokine signaling and humoral and cellular immunity (P value<0.05). Further interactive network analysis depicted effects of EPS-associated genes on networks linked to inflammation, immunological response, and cell proliferation. Gene expression changes were confirmed by qRT-PCR for a subset of the differentially expressed genes. EPS patient tissues exhibited elevated expression of genes encoding sulfatase1, thrombospondin 1, fibronectin 1 and alpha smooth muscle actin, among many others, while in EPS and PD tissues mRNAs encoding leptin and retinol-binding protein 4 were markedly down-regulated, compared to Uremic group patients. Immunolocalization of Collagen 1 alpha 1 revealed that Col1a1 protein was predominantly expressed in the submesothelial compact zone of EPS patient peritoneal samples, whereas PD patient peritoneal samples exhibited homogenous Col1a1 staining throughout the tissue samples. The results are compatible with the hypothesis that encapsulating peritoneal sclerosis is a distinct pathological process from the simple peritoneal fibrosis that accompanies all PD treatment.

ABSTRACT

To investigate the role of FMS-like tyrosine kinase 1 (FLT1, also known as VEGFR1) signaling during pregnancy, mice were injected with anti-FLT1 neutralizing antibody (Ab) beginning on Gestational Day 8 or 12 and every other day thereafter until Day 18; vehicle-only injected mice served as controls. Uterine artery blood flow was measured with ultrasound on Days 13 and 18, and morphometric measurements of the uterine arcade were carried out on Day 19 to provide a measure of gestational vascular remodeling; reproductive performance was evaluated by determining litter size, resorption rates, and pup and placental weights. Ab injections beginning on Day 8 or Day 12 resulted in significant reductions of uterine artery peak systolic and diastolic flows at Days 13 and 18. In addition, normal reproductive function was compromised, as evidenced by a significant reduction in average number of viable pups along with enhanced resorption rates. Reproductive performance was also significantly compromised in this group, although less severely. There was no evidence of a reduction in main uterine artery diameters, though arterial distensibility was reduced, and the diameter of the main uterine vein was significantly smaller in the Ab-injected mice. Significant reductions in main uterine artery and segmental artery length were also noted. Placental and pup weights were similar in all the groups. FLT1 inhibition during murine pregnancy impaired blood flow to the fetal-placental unit, compromised several indices of vascular remodeling, reduced fecundity, and increased fetal reabsorptions. The effects of FLT1 inhibition are most pronounced when targeted during early pregnancy.

Systemic inhibition of FLT1 signaling during normal murine pregnancy is associated with significant fetal loss, abnormal uteroplacental blood flow, and altered remodeling and biomechanical properties of the uterine circulation.

To evaluate whether angiogenic factor levels correlate with preeclampsia-related adverse maternal and perinatal outcomes in women with twin pregnancy, we studied 79 women with suspected preeclampsia in the 3rd trimester. Anti-angiogenic soluble fms-like tyrosine kinase 1 (sFlt1) and pro-angiogenic placental growth factor (PlGF) were measured at presentation on an automated platform. An adverse outcome was defined as hemolysis elevated liver enzymes and low platelets syndrome; disseminated intravascular coagulation; abruption; pulmonary edema; cerebral hemorrhage; maternal, fetal and neonatal death; eclampsia; acute renal failure; small for gestational age; and indicated delivery. All outcomes were ascertained 2 weeks after initial evaluation. Comparing the 52 (65.8%) women who experienced an adverse outcome to the 27 (34.2%) women without an adverse outcome, the median sFlt1 was elevated [11461.5 pg/ml (8794.0–14847.5) versus 7495.0 pg/ml (3498.0–10482.0, P=0.0004], PlGF was reduced [162.5 pg/ml (98.0–226.5) versus 224.0 pg/ml (156.0–449.0), P=0.005] and sFlt1/PlGF ratio was elevated [74.2 (43.5–110.5) versus 36.2 (7.1–71.3), P=0.0005]. Among those presenting <34 weeks (n=40), the difference in sFlt1/PlGF ratio was more striking [97.7 (76.6–178.1) versus 31.7 (6.5–48.7); P=0.001]. Addition of sFlt1/PlGF to the highest systolic blood pressure and proteinuria improved prediction of adverse outcomes. We conclude that in women with twin pregnancy and suspected preeclampsia, the sFlt1/PlGF ratio at the time of initial evaluation is associated with subsequent adverse maternal and perinatal outcomes. These findings are similar to singleton pregnancies and may implicate common pathogenic pathways.

Objective

To test utility of cystatin-C as a marker of glomerular filtration rate during pregnancy, we performed serial correlations with inulin clearance during pregnancy and postpartum.

Methods

Twelve subjects received inulin infusions and serum cystatin-C at three time points. Pearson's correlation coefficient was calculated.

Results

Cystatin-C levels ranged 0.66 to 1.48 mg/L during pregnancy, and 0.72 to 1.26 mg/L postpartum. Inulin clearance ranged 130 to 188 ml/min during pregnancy, and 110 to 167 ml/min postpartum. Cystatin-C did not correlate with inulin clearance at any time point.

Conclusion

Serum cystatin-C did not correlate with inulin clearance during pregnancy or postpartum.

Objective

The objective was to evaluate whether intravenous magnesium sulfate (magnesium) alters levels of angiogenic factors in women with preeclampsia.

Study Design

This was a prospective cohort study comparing women with preeclampsia treated with magnesium for seizure prophylaxis to those who were not. Serum levels of angiogenic factors, soluble fms-like tyrosine kinase 1, soluble endoglin and placental growth factor, were measured at the time of diagnosis and approximately 24 hours later. Secondary analysis compared women receiving magnesium for preeclampsia to women receiving magnesium for preterm labor. Analysis of covariance was used to compare levels at 24 hours, adjusting for levels at enrollment and potential confounders.

Results

Angiogenic factor levels did not differ between preeclampsia groups with and without magnesium or between preeclampsia and preterm labor groups treated with magnesium (all P > 0.05).

Conclusion

Magnesium likely decreases seizure risk in preeclampsia by a mechanism other than altering angiogenic factor levels.

Prior studies showed conflicting results regarding the association between 25-hydroxyvitamin D (25(OH)D) levels and mineral metabolism in end-stage renal disease. In order to determine whether the bioavailable vitamin D (that fraction not bound to vitamin D binding protein) associates more strongly with measures of mineral metabolism than total levels, we identified 94 patients with previously measured 25(OH)D and 1,25-dihydroxyvitamin D (1,25(OH)2D) from a cohort of incident hemodialysis patients. Vitamin D binding protein was measured from stored serum samples. Bioavailable 25(OH)D and 1,25(OH)2D were determined using previously validated formulae. Associations with demographic factors and measures of mineral metabolism were examined. When compared with whites, black patients had lower levels of total, but not bioavailable, 25(OH)D. Bioavailable, but not total, 25(OH)D and 1,25(OH)2D were each significantly correlated with serum calcium. In univariate and multivariate regression analysis, only bioavailable 25(OH)D was significantly associated with parathyroid hormone levels. Hence, bioavailable vitamin D levels are better correlated with measures of mineral metabolism than total levels in patients on hemodialysis.

Peri-partum cardiomyopathy (PPCM) is a frequently fatal disease that affects women near delivery, and occurs more frequently in women with pre-eclampsia and/or multiple gestation. The etiology of PPCM, or why it associates with pre-eclampsia, remains unknown. We show here that PPCM is associated with a systemic angiogenic imbalance, accentuated by pre-eclampsia. Mice that lack cardiac PGC-1α, a powerful regulator of angiogenesis, develop profound PPCM. Importantly, the PPCM is entirely rescued by pro-angiogenic therapies. In humans, the placenta in late gestation secretes VEGF inhibitors like soluble Flt1 (sFlt1), and this is accentuated by multiple gestation and pre-eclampsia. This anti-angiogenic environment is accompanied by sub-clinical cardiac dysfunction, the extent of which correlates with circulating levels of sFlt1. Exogenous sFlt1 alone caused diastolic dysfunction in wildtype mice, and profound systolic dysfunction in mice lacking cardiac PGC-1α. Finally, plasma samples from women with PPCM contained abnormally high levels of sFlt1. These data strongly suggest that PPCM is in large part a vascular disease, caused by excess anti-angiogenic signaling in the peri-partum period. The data also explain how late pregnancy poses a threat to cardiac homeostasis, and why pre-eclampsia and multiple gestation are important risk factors for the development of PPCM.

Background

The objective of this study was to comprehensively profile biological factors in pregnancy that have been postulated to be important components of the in utero environment and may also have relevance to later susceptibility to cancer and other chronic diseases.

Methods

Steroid sex hormones, IGFs, and angiogenic factors were measured in maternal and cord serum from term, normotensive pregnancies. Spearman correlations and linear regression estimated relationships among the biological factors and clinical characteristics.

Results

The analytes were generally not correlated between maternal and fetal circulations. However, significant correlations were demonstrated among several analytes within maternal or cord samples. A few analytes were associated with clinical characteristics (e.g., maternal IGF-1and IGFBP-3 were inversely correlated with offspring birth weight, while maternal leptin and cord testosterone were positively correlated with this characteristic). Maternal androgens were higher in African-Americans than whites and maternal PlGF and soluble fms-like tyrosine kinase-1 (sFlt-1) were higher in male than female offspring.

Conclusions

There were significant correlations among analytes but the patterns differed depending on whether they were measured in the maternal or fetal circulation. The number and magnitude of correlations among analytes, however, should affect the design and interpretation of future studies.

Background

The purpose of this study was to compare plasma soluble endoglin (sEng) levels with standard clinical evaluation or plasma levels of other angiogenic proteins [soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF)] in predicting short-term adverse maternal and perinatal outcomes in women with suspected preeclampsia presenting prior to 34 weeks.

Methods and Findings

Data from all women presenting at <34 weeks for evaluation of preeclampsia with singleton pregnancies (July 2009−October 2010) were included in this analysis and sEng levels were measured at presentation. Data was analyzed for 170 triage encounters and presented as median {25−75th centile}. Thirty-three percent of patients (56 of 170) experienced an adverse outcome. sEng levels (ng/ml) were significantly elevated in patients who subsequently experienced adverse outcomes compared to those who did not (32.3 {18.1, 55.8} vs 4.8 {3.2, 8.6}, p<0.0001). At a 10% false positive rate, sEng had higher detection rates of adverse outcomes than the combination of highest systolic blood pressure, proteinuria and abnormal laboratory tests (80.4 {70.0, 90.8} vs 63.8 {51.4, 76.2}, respectively). Subjects in the highest quartile of sEng were more likely to deliver early compared to those in the lowest quartile (HR: 14.96 95% CI: 8.73−25.62, p<0.0001). Natural log transformed sEng correlated positively with log sFlt1 levels (r = 0.87) and inversely with log PlGF levels (r = −0.79) (p<0.0001 for both). Plasma sEng had comparable area under the curve for prediction of adverse outcomes as measurement of sFlt1/PlGF ratio (0.88 {0.81, 0.95} for sEng versus 0.89 {0.83, 0.95} for sFlt1/PlGF ratio, p = 0.74).

Conclusions

In women with suspected preeclampsia presenting prior to 34 weeks of gestation, sEng performs better than standard clinical evaluation in detecting adverse maternal and fetal outcomes occurring within two weeks of presentation. Soluble endoglin was strongly correlated with sFlt1 and PlGF levels, suggesting common pathogenic pathways leading to preeclampsia.

OBJECTIVE

To test the hypothesis that high circulating concentrations of maternal anti-angiogenic factors are associated with increased risk of respiratory distress syndrome (RDS).

STUDY DESIGN

This is a nested case-control study of nulliparous women who delivered less than 37 weeks of gestation within the Calcium for Preeclampsia Prevention (CPEP) trial. The study included 116 women with preeclampsia or gestational hypertension and 323 normotensive controls. Soluble fms-like tyrosine kinase 1 (sFlt1), placental growth factor [PlGF] and soluble endoglin [sEng] in maternal serum were measured at 21–32 weeks of gestation.

RESULTS

Preterm infants born to hypertensive mothers were more likely to develop RDS (22.5 % versus 20.9%, P=0.03). After adjustment for gestational age at delivery, the odds ratio for the relationship between hypertension in pregnancy and RDS was 2.18 (95% C.I. 1.08, 4.39). In hypertensive pregnancies women whose infants developed RDS had significantly higher circulating mean sFlt1 levels during mid-pregnancy (21–32 weeks of gestation) even after adjustment for gestational age at delivery (21,516 pg/mL versus 7,000 pg/mL, P = 0.01).

CONCLUSIONS

Preterm preeclampsia and gestational hypertension, characterized by high circulating levels of sFlt1, are associated with a twofold increased risk of RDS in infants delivered before 37 weeks. Among women with these hypertensive pregnancies circulating sFlt1 concentrations during mid-pregnancy were substantially higher in women whose infants developed RDS.

Objective

The objective of this study is to define the ultrasonographic changes in the cardiovascular and uteroplacental circulation of normal pregnant mice compared to non-pregnant mice using high-frequency, high-resolution ultrasonography.

Methods

Ten to twelve-week-old CD-1 mice (six non-pregnant and six pregnant animals) were used for all experiments. Vevo® 2100 (VisualSonics) was used to evaluate the cardiovascular and uteroplacental circulation physiology. Cardiac echocardiogram and uterine artery Doppler studies were performed on all animals. Pregnant animals were evaluated on embryonic day seven (E7), thirteen (E13) and eighteen (E18). Fetal heart rate and umbilical artery Doppler flows were obtained on pregnant animals. Three-dimensional ultrasonography imaging was utilized for quantification of placental volumes. All data are presented as median {10th–90th percentiles}.

Results

In pregnant mice on E7 compared to non-pregnant mice, there was an increase in cardiac output (p=0.008), stroke volume (p=0.002), ejection fraction, (p=0.02) and fractional shortening (p=0.02). The maternal heart rate increased throughout gestation (p= 0.009). During pregnancy, a gestational sac was clearly visible on E7. Between E13 and E18, the fetal size and fetal heart rate increased (p=0.001) and the umbilical artery peak systolic velocity increased (p <0.001). Minimal diastolic blood flow was observed in the umbilical artery on E13, which increased slightly on day E18 (p=0.01). There was also no change in the uterine artery resistance index between non-pregnant and pregnant mice. The placental volume increased between E13 and E18 (p=0.03).

Conclusion

Several changes noted in cardiovascular and uteroplacental systems occurring during normal murine pregnancy have striking similarities to humans and can be accurately measured using newer ultrasonographic techniques. Further studies are needed to evaluate changes in these vascular beds in mouse models of diseases such as preeclampsia and intrauterine growth restriction.

Aims

Vitamin D deficiency is associated with cardiac hypertrophy and heart failure, and vitamin D therapy prevents the progression of cardiac hypertrophy in animal models. Here, we examine whether vitamin D therapy prevents progression of pre-existing cardiac hypertrophy and development of heart failure.

Methods and results

When male Dahl salt-sensitive rats were fed a high salt (HS) diet, all rats developed cardiac hypertrophy after 5 weeks. Thereafter, rats were treated with vehicle (V), paricalcitol (PC, an active vitamin D analogue, at 200 ng, IP 3x/week), enalapril (EP, 90 μg/day), and PC + EP. All groups were continued on the HS diet and evaluated after 4 weeks of therapy. The PC and PC + EP groups, but not the V and EP only groups, showed significant prevention of progression of pre-existing cardiac hypertrophy. The signs of decompensated heart failure were evident in the vehicle-treated group; these heart failure parameters significantly improved with PC, EP or PC + EP therapy. The expression of PKCα, which is regulated by Ca2+and known to stimulate cardiac hypertrophy, was significantly increased in the vehicle group, and PC, EP or PC + EP effectively decreased PKCα activation. We also observed normalization of genetic alterations during progression to heart failure with PC treatment.

Conclusion

PC treatment resulted in both the prevention of progression of pre-existing cardiac hypertrophy and the development of heart failure, compared with improvement in progression to heart failure by EP alone. These beneficial findings in heart were associated with inhibition of PKCα activation and reversal of gene alterations.

Background

An imbalance in circulating angiogenic factors plays a central role in the pathogenesis of preeclampsia.

Methods and Results

We prospectively studied 616 women who were evaluated for suspected preeclampsia. We measured plasma levels of antiangiogenic soluble fms-like tyrosine kinase 1 (sFlt1) and proangiogenic placental growth factor (PlGF) at presentation, and examined for an association between sFlt1/PlGF ratio and subsequent adverse maternal and perinatal outcomes within 2 weeks.

The median [25th–75th centile] sFlt1/PlGF ratio at presentation was elevated in participants who experienced any adverse outcome compared to those who did not (47.0 [15.5–112.2] versus 10.8 [4.1–28.6], p<0.0001). Among those presenting <34 weeks (N=167), the results were more striking (226.6 [50.4–547.3] versus 4.5 [2.0–13.5], p<0.0001), and the risk was markedly elevated when the highest sFlt1/PlGF ratio tertile was compared to the lowest (OR 47.8, 95% CI 14.6–156.6). Among participants presenting at <34 weeks, the addition of sFlt1/PlGF ratio to hypertension and proteinuria significantly improved the prediction for subsequent adverse outcomes (AUC=0.93 for hypertension, proteinuria, and sFlt1/PlGF versus AUC=0.84 for hypertension and proteinuria alone; P=0.001). Delivery occurred within two weeks of presentation in 86.0% of women with sFlt1/PlGF ratio ≥ 85 compared with 15.8% of women with sFlt1/PlGF ratio <85 (HR 15.2, 95% CI 8.0–28.7).

Conclusions

In women with suspected preeclampsia presenting at <34 weeks, circulating sFlt1/PlGF ratio predicts adverse outcomes occurring within two weeks. The accuracy of this test is substantially better than current approaches and may be useful in risk stratification and management. Additional studies are warranted to validate these findings.

The cardinal manifestations of the pregnancy-specific disorder preeclampsia, new-onset hypertension and proteinuria that resolve with placental delivery, have been linked to an extracellular protein made by the placenta, sFlt1 (soluble fms-like tyrosine kinase 1), that injures the maternal vasculature. However, the mechanisms by which sFlt1, which is heavily matrix-bound, gains access to the systemic circulation remain unclear. Here we report that the preeclamptic placenta’s outermost layer, the syncytiotrophoblast, forms abundant “knots” that are enriched with sFlt1 protein. These syncytial knots easily detach from the syncytiotrophoblast, resulting in free, multinucleated aggregates (50–150 μm diameter) that are loaded with sFlt1 protein and mRNA, are metabolically active, and are capable of de novo gene transcription and translation. At least 25% of the measurable sFlt1 in 3rd trimester maternal plasma is bound to circulating placental microparticles. We conclude that detachment of syncytial knots from the placenta results in free, transcriptionally active syncytial aggregates that represent an autonomous source of sFlt1 delivery into the maternal circulation. The process of syncytial knot formation, shedding of syncytial aggregates, and appearance of placental microparticles in the maternal circulation appears to be greatly accelerated in preeclampsia and may contribute to the maternal vascular injury that characterizes this disorder.

Studies examining the relationship between total circulating 25-hydroxyvitamin D [25(OH)D] levels and bone mineral density (BMD) have yielded mixed results. Vitamin D–binding protein (DBP), the major carrier protein for 25(OH)D, may alter the biologic activity of circulating vitamin D. We hypothesized that free and bioavailable 25(OH)D, calculated from total 25(OH)D, DBP, and serum albumin levels, would be more strongly associated with BMD than levels of total 25(OH)D. We measured total 25(OH)D, DBP, and serum albumin levels in 49 healthy young adults enrolled in the Metabolic Abnormalities in College-Aged Students (MACS) study. Lumbar spine BMD was measured in all subjects using dual-energy X-ray absorptiometry. Clinical, diet, and laboratory information also was gathered at this time. We determined free and bioavailable (free + albumin-bound) 25(OH)D using previously validated formulas and examined their associations with BMD. BMD was not associated with total 25(OH)D levels (r = 0.172, p = .236). In contrast, free and bioavailable 25(OH)D levels were positively correlated with BMD (r = 0.413, p = .003 for free, r = 0.441, p = .002 for bioavailable). Bioavailable 25(OH)D levels remained independently associated with BMD in multivariate regression models adjusting for age, sex, body mass index, and race (p = .03). It is concluded that free and bioavailable 25(OH)D are more strongly correlated with BMD than total 25(OH)D. These findings have important implications for vitamin D supplementation in vitamin D–deficient states. Future studies should continue to explore the relationship between free and bioavailable 25(OH)D and health outcomes.

Objective

To describe relations among maternal demographic and lifestyle characteristics and mid-pregnancy levels of angiogenic markers (soluble Fms-like tyrosine kinase-1 (sFlt-1); placental growth factor (PlGF); soluble endoglin (sEng)).

Study Design

In a large pregnancy cohort, linear models were used to evaluate relations among maternal characteristics and mid-pregnancy angiogenic markers with and without covariate adjustment. Associations were examined in a sub-cohort including term and preterm deliveries (N = 1302) and among “normal” term pregnancies (N = 668).

Results

Concentrations of all factors declined with increasing maternal BMI. Multiparous women had lower sFlt-1 levels than primiparas. Higher PlGF and slightly lower sEng were observed among women who smoked at enrollment, but not among those who quit before enrollment. African-American women had higher levels of all markers.

Conclusions

Understanding relations among maternal characteristics and levels of angiogenic factors may improve studies utilizing these markers to examine etiologies and/or to predict adverse pregnancy outcome.

The malignant transformation of a normal cell into a cancer cell requires no vasculature. Growth of solid tumors, however, requires angiogenesis to provide oxygen and nutrients to support cell proliferation. The switch from an avascular to a vascular phenotype is typically associated with acceleration of tumor growth. Antiangiogenic therapy, starving a tumor of its blood supply, is an attractive addition to the anticancer armamentarium. Animal tests of antiangiogenic therapy have shown remarkable potential. Initial human trials have proven antiangiogenic therapy to be remarkably nontoxic. Numerous antiangiogenic agents have been isolated as proteolytic fragments of endogenous polypeptides of the extracellular matrix. Endostatin was the first such antiangiogenic protein described and its potent antitumor effects in mice have generated wide interest. This review summarizes recent advances in endostatin biology and highlights new results on the cellular and subcellular mechanisms of endostatin action.

Objective

To determine if eclampsia has a different circulating profile of angiogenic [placental growth factor (PlGF)] and anti-angiogenic factors [soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and soluble endoglin (sEng)] than severe preeclampsia.

Study Design

This cross-sectional study included women in the following groups: 1) normal pregnancy (n=40); 2) severe preeclampsia (n=40); and 3) eclampsia (n=20). Maternal serum PlGF, sVEGFR-1, and sEng concentrations were determined using ELISA.

Results

1) The median concentration of sVEGFR-1 and sEng was higher and of PlGF lower in severe preeclampsia or eclampsia than in normal pregnancy (p<0.001 for all); 2) the median concentrations of these 3 analytes did not differ significantly between the severe preeclampsia and eclampsia groups.

Conclusions

Eclampsia is associated with higher maternal circulating concentrations of sVEGFR-1 and sEng and lower concentrations of PlGF than normal pregnancy, but with similar concentrations to severe preeclampsia. These findings suggest that eclampsia shares a common pathogenic pathway as severe preeclampsia.

Hemolytic uremic syndrome (HUS) is a potentially life-threatening condition. It often occurs after gastrointestinal infection with E. coli O157:H7, which produces Shiga toxins (Stx) that cause hemolytic anemia, thrombocytopenia, and renal injury. Stx-mediated changes in endothelial phenotype have been linked to the pathogenesis of HUS. Here we report our studies investigating Stx-induced changes in gene expression and their contribution to the pathogenesis of HUS. Stx function by inactivating host ribosomes but can also alter gene expression at concentrations that minimally affect global protein synthesis. Gene expression profiling of human microvascular endothelium treated with Stx implicated a role for activation of CXCR4 and CXCR7 by their shared cognate chemokine ligand (stromal cell–derived factor-1 [SDF-1]) in Stx-mediated pathophysiology. The changes in gene expression required a catalytically active Stx A subunit and were mediated by enhanced transcription and mRNA stability. Stx also enhanced the association of CXCR4, CXCR7, and SDF1 mRNAs with ribosomes. In a mouse model of Stx-mediated pathology, we noted changes in plasma and tissue content of CXCR4, CXCR7, and SDF-1 after Stx exposure. Furthermore, inhibition of the CXCR4/SDF-1 interaction decreased endothelial activation and organ injury and improved animal survival. Finally, in children infected with E. coli O157:H7, plasma SDF-1 levels were elevated in individuals who progressed to HUS. Collectively, these data implicate the CXCR4/CXCR7/SDF-1 pathway in Stx-mediated pathogenesis and suggest novel therapeutic strategies for prevention and/or treatment of complications associated with E. coli O157:H7 infection.

Therapies that target the vascular endothelial growth factor (VEGF) pathway cause hypertension but the mechanism remains unknown. This cross-sectional study tested the hypothesis that VEGF inhibition causes hypertension by suppressing VEGF-mediated vasodilatory pathways. Urine was collected from 80 patients with metastatic renal cell carcinoma from 2002–2009, 40 at baseline and 40 while on VEGF inhibitors. Measured urinary biomarkers include albumin, metabolites of the nitric oxide pathway and its downstream effector, cGMP, and prostaglandin pathway biomarkers prostaglandin E2, 6-keto PGF 1α, and cAMP, all normalized to urinary creatinine. The mean age in both groups was 61.8 years, 76% were male, and urinary albumin was higher in patients receiving VEGF inhibitors (median 18.4mg/g vs. 4.6 mg/g; p=0.009). cGMP/Cr was suppressed in patients on VEGF inhibitors (0.28 pmol/ug vs. 0.39 pmol/ug; p=0.01), with a trend toward suppression of nitrate/Cr (0.46 umol/mg vs. 0.62 umol/mg; p=0.09). Both comparisons were strengthened when patients on bevacizumab were excluded and only those receiving small molecule tyrosine kinase inhibitors were analyzed (cGMP/Cr, p=0.003; Nitrate/Cr, p=0.01). Prostaglandin E2, 6-keto PGF1α, and cAMP did not differ between groups. These results suggest that hypertension induced by VEGF inhibitors is mediated by suppression of nitric oxide production. Prospective studies are needed to explore whether these biomarkers may be useful predictors of efficacy in patients receiving VEGF-targeted therapies.

Drugs that inhibit the vascular endothelial growth factor (VEGF) signaling pathway are a rapidly growing chemotherapy class for treatment of solid tumors. This “targeted therapy” is more specific than traditional chemotherapy, causing fewer side effects. However, VEGF-targeted therapies cause hypertension in 30 – 80% of patients. Unlike traditional “off-target” side effects, hypertension is a mechanism-dependent, “on-target” toxicity – reflecting effective inhibition of the VEGF signaling pathway rather than non-specific effects on unrelated signaling pathways. In this article, we review current understanding of the mechanisms of VEGF-targeted therapy-induced hypertension, discuss similarities with preeclampsia, review implications for therapy of this increasingly common clinical problem and discuss the potential use of blood pressure rise as a biomarker for proper drug dosing and effective VEGF pathway inhibition.

Sepsis-associated acute kidney injury (AKI) is a common and morbid condition that is distinguishable from typical ischemic renal injury by its paucity of tubular cell death. The mechanisms underlying renal dysfunction in individuals with sepsis-associated AKI are therefore less clear. Here we have shown that endotoxemia reduces oxygen delivery to the kidney, without changing tissue oxygen levels, suggesting reduced oxygen consumption by the kidney cells. Tubular mitochondria were swollen, and their function was impaired. Expression profiling showed that oxidative phosphorylation genes were selectively suppressed during sepsis-associated AKI and reactivated when global function was normalized. PPARγ coactivator–1α (PGC-1α), a major regulator of mitochondrial biogenesis and metabolism, not only followed this pattern but was proportionally suppressed with the degree of renal impairment. Furthermore, tubular cells had reduced PGC-1α expression and oxygen consumption in response to TNF-α; however, excess PGC-1α reversed the latter effect. Both global and tubule-specific PGC-1α–knockout mice had normal basal renal function but suffered persistent injury following endotoxemia. Our results demonstrate what we believe to be a novel mechanism for sepsis-associated AKI and suggest that PGC-1α induction may be necessary for recovery from this disorder, identifying a potential new target for future therapeutic studies.

Objective

Preeclampsia is diagnosed using clinical criteria and in atypical cases the diagnosis may be inaccurate as there are no specific tests to confirm or exclude preeclampsia. This study sought to evaluate the utility of angiogenic biomarkers, sFlt1, sEng and PlGF to distinguish patients with gestational thrombocytopenia and immune thrombocytopenic purpura (ITP) from patients with thrombocytopenia resulting from the HELLP syndrome, a complication of severe preeclampsia.

Methods

Serum was collected and the angiogenic biomarkers of patients with ITP and gestational thrombocytopenia (N=9) were compared to patients with HELLP (N=11) and preeclampsia (N=11). Circulating levels of these angiogenic biomarkers were also compared by gestational age to 1564 randomly selected normotensive women from the Calcium for Preeclampsia Prevention study.

Results

Patients with non-HELLP thrombocytopenia had lower sFlt1 (7.3 +/- 3.8 ng/mL vs 15.5 +/- 5 ng/mL, p<0.001), lower sEng (8.7 +/- 3.6 vs 34 +/- 17, p <0.001) and higher PlGF (484 +/- 412 vs 66.3 +/- 44, p= 0.003) than patients with HELLP syndrome. Angiogenic factor abnormalities in patients with preeclampsia were similar to patients with HELLP syndrome, suggesting a common pathogenesis. Patients with non-HELLP thrombocytopenia had angiogenic profiles similar to normotensive controls, whereas patients with HELLP syndrome had levels higher than the 90th percentile for sFlt1 and sEng and lower than the 10th percentile for PLGF.

Conclusion

Angiogenic biomarkers may be useful in excluding conditions, which mimic preeclampsia.