There are about 2.5 million glomeruli in the kidneys each consisting of a barrel of glomerular basement membrane surrounded by glomerular endothelial cells on the inside and glomerular epithelial cells with established foot processes (podocytes) on the outside. Defects in this filtration apparatus lead to glomerular vascular leak or proteinuria. The role of vascular endothelial growth factor (VEGF) in the regulation of glomerular vascular permeability is still unclear. Recent studies indicate that patients receiving anti-VEGF antibody therapy may have an increased incidence of proteinuria. In a different setting, pregnancies complicated by preeclampsia are associated with elevated soluble VEGF receptor 1 protein (sFlt-1), endothelial cell dysfunction and proteinuria. These studies suggest that neutralization of physiologic levels of VEGF, a key endothelial survival factor, may lead to proteinuria. In the present study, we evaluated the potential of anti-VEGF neutralizing antibodies and sFlt-1 in the induction of proteinuria. Our studies demonstrate that anti-VEGF antibodies and sFlt-1 cause rapid glomerular endothelial cell detachment and hypertrophy, in association with down-regulation of nephrin, a key epithelial protein in the glomerular filtration apparatus. These studies suggest that down-regulation or neutralization of circulating VEGF may play an important role in the induction of proteinuria in various kidney diseases, some forms of cancer therapy and also in women with preeclampsia.
"In pre - eclampsia , sFlt - 1 is elevated and has since been considered a marker for pre - eclampsia ( Vuorela et al . , 2000 ; Buhimschi et al . , 2005 ) . In Wt mice , neutralization of VEGF - induced proteinuria ( Sugimoto et al . , 2003 ) and sFlt - 1 gene transfer provoked pre - eclampsia - like signs ( Maynard et al . , 2003 ; Lu et al . , 2007 ) . Cudmore et al . ( 2007 ) showed that , in vitro , the overexpression of HO - 1 in endothelial cells by using a retrovirus - inhibited sFlt - 1 release , whereas HO - 1 inhibition potentiated sFlt - 1 production from endoth"
[Show abstract][Hide abstract] ABSTRACT: The onset of pregnancy implies the appearance of a new organ, the placenta. One main function of the placenta is to supply oxygen to the fetus via hemoproteins. In this review, we highlight the importance of the enzyme heme oxygenase-1 (HO-1) for pregnancy to be established and maintained. HO-1 expression is pivotal to promote placental function and fetal development, thus determining the success of pregnancy. The deletion of the gene Hmox1 in mice leads to inadequate remodeling of spiral arteries and suboptimal placentation followed by intrauterine growth restriction (IUGR) and fetal lethality. A partial Hmox1 deletion leads to IUGR as well, with heterozygote and wild-type fetuses being born, but Hmox1-/- significantly below the expected Mendelian rate. This strong phenotype is associated with diminished number of pregnancy-protective uterine natural killer (uNK) cells. Pregnant heterozygote females develop gestational hypertension. The protective HO-1 effects on placentation and fetal growth can be mimicked by the exogenous administration of carbon monoxide (CO), a product of heme catalyzed by HO-1. CO application promotes the in situ proliferation of uNK cells, restores placentation and fetal growth, while normalizing blood pressure. Similarly, HO-1 inhibition provokes hypertension in pregnant rats. The HO-1/CO axis plays a pivotal role in sustaining pregnancy and aids in the understanding of the biology of pregnancy and reveals a promising therapeutic application in the treatment of pregnancy complications.
Frontiers in Pharmacology 12/2014; 5. DOI:10.3389/fphar.2014.00291 · 3.80 Impact Factor
"BJP A Ahmed and W Ramma damage and proteinuria (Sugimoto et al., 2003). Cancer patients receiving anti-VEGF therapy exhibit pre–eclampsialike symptoms, suggesting that decreased bioavailability of VEGF causes these symptoms (Kabbinavar et al., 2003). "
[Show abstract][Hide abstract] ABSTRACT: Preeclampsia is like a car with failed brakes. Statins up the brakes & could cure preeclampsia. Watch this video - http://youtu.be/vWUCWbKo1dE We discovered the two protective enzyme systems to prevent preeclampsia: the role of heme oxygenase-1 (Hmox1/CO) and cystathionine gama-lyase (CSE/H2S) pathways. We showed that statins induce these enzymes and inhibit a culprit protein called sFlt-1. We developed a therapy and led The StAmP Trial. Statins may quite possibly prevent or treat preeclampsia. It's a start not a panacea for pregnancy complications. http://youtu.be/vWUCWbKo1dE
"We further explored the correlations of elevated sFlt-1 with proteinuria, hypertension, Oxford-E scores and vWF levels (Figure S1). Previous studies in animal models and humans have proven the importance of VEGF signaling in maintaining the integrity of glomerular filtration barrier, . A defective survival of glomerular endothelial cells would occur in the absence of VEGF signaling, which leads to proteinuria. "
[Show abstract][Hide abstract] ABSTRACT: Background
Endothelial injury, which may present clinically as hypertension, proteinuria and increased von Willebrand Factor (vWF) level, is a common manifestation in IgA nephropathy (IgAN). However, causal factors for endothelial injury in IgAN are not completely understood. An imbalance of vascular endothelial growth factor/Soluble fms-like tyrosine kinase-1 (VEGF/sFlt-1) has been observed in many diseases with endothelial dysfunction, including pre-eclampsia and diabetic retinopathy, but whether it contributes to endothelial injury in IgAN requires further exploration.
Initially, 96 IgAN patients and 22 healthy volunteers were enrolled as a discovery cohort. VEGF/sFlt-1, sFlt-1 and VEGF levels were compared between patients with IgAN and healthy volunteers to explore the underlying factors that contribute to endothelial injury in IgAN. The identified contributor (sFlt-1) was further confirmed in a replication cohort, which included 109 IgAN patients and 30 healthy volunteers. Correlations of sFlt-1 with hypertension, proteinuria, Oxford-E score and plasma vWF were further evaluated in the combined 205 patients with IgAN.
VEGF/sFlt-1 levels were significantly lower in IgAN patients than healthy volunteers (0.33±0.27 vs. 0.43±0.22, p = 0.02) in the discovery cohort. Within the ratio, plasma sFlt-1 levels were significantly elevated (101.18±25.19 vs. 79.73±18.85 pg/ml, p<0.001), but plasma VEGF levels showed no significant differences. Elevated sFlt-1 levels in the replication cohort were confirmed in IgAN patients (93.40±39.78 vs. 71.92±15.78 pg/ml, p<0.001). Plasma sFlt-1 levels in IgAN patients correlated with proteinuria (severe (>3.5 g/d) vs. moderate (1–3.5 g/d) vs. mild (<1 g/d) proteinuria: 115.95±39.09 vs. 99.89±28.55 vs. 83.24±33.92 pg/ml; severe vs. mild: p<0.001, moderate vs. mild p = 0.001, severe vs. moderate: p = 0.014), hypertension (with vs. without hypertension: 107.87±31.94 vs. 87.32±32.76 pg/ml, p = 0.015) and vWF levels (r = 0.161, p = 0.021).
The present study found elevated sFlt-1 in IgAN patients and further identified its correlation with proteinuria, hypertension and vWF levels. These results suggested that elevated sFlt-1 contributes to endothelial injury in IgAN.
PLoS ONE 07/2014; 9(7):e101779. DOI:10.1371/journal.pone.0101779 · 3.23 Impact Factor
M J Torres-Sánchez, E Ávila-Barranco, R J Esteban de la Rosa, R Fernández-Castillo, M A Esteban, J J Carrero, M García-Valverde, J A Bravo-Soto
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