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In vivo experiments reveal the good, the bad and the ugly faces of sFlt-1 in pregnancy.

Szalai G, Xu Y, Romero R, Chaiworapongsa T, Xu Z, Chiang PJ, Ahn H, Sundell B, Plazyo O, Jiang Y, Olive M, Wang B, Jacques SM, Qureshi F, Tarca AL, Erez O, Dong Z, Papp Z, Hassan SS, Hernandez-Andrade E, Than NG - PLoS ONE (2014)

Bottom Line: Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1.MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos.In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development.

View Article: PubMed Central - PubMed

Affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI, United States of America.

ABSTRACT

Objective: Soluble fms-like tyrosine kinase (sFlt)-1-e15a, a primate-specific sFlt-1-isoform most abundant in the human placenta in preeclampsia, can induce preeclampsia in mice. This study compared the effects of full-length human (h)sFlt-1-e15a with those of truncated mouse (m)sFlt-1(1-3) used in previous preeclampsia studies on pregnancy outcome and clinical symptoms in preeclampsia.

Methods: Mice were injected with adenoviruses or fiber-mutant adenoviruses overexpressing hsFlt-1-e15a, msFlt-1(1-3) or control GFP under the CMV or CYP19A1 promoters on gestational day 8 (GD8) and GD11. Placentas and pups were delivered by cesarean section, and dams were monitored postpartum. Blood pressure was telemetrically recorded. Urine samples were collected with cystocentesis and examined for albumin/creatinine ratios. Tissue specimens were evaluated for transgene as well as endogenous mFlt-1 and msFlt-1-i13 expression. H&E-, Jones- and PAS-stained kidney sections were histopathologically examined. Placental GFP expression and aortic ring assays were investigated with confocal microscopy.

Results: Mean arterial blood pressure (MAP) was elevated before delivery in hsFlt-1-e15a-treated mice compared to controls (GD18: ΔMAP = 7.8 mmHg, p = 0.009), while ΔMAP was 12.8 mmHg (GD18, p = 0.005) in msFlt-1(1-3)-treated mice. Urine albumin/creatinine ratio was higher in hsFlt-1-e15a-treated mice than in controls (GD18, p = 0.04; PPD8, p = 0.03), and msFlt-1(1-3)-treated mice had marked proteinuria postpartum (PPD8, p = 4 × 10(-5)). Focal glomerular changes were detected in hsFlt-1-e15a and msFlt-1(1-3)-treated mice. Aortic ring microvessel outgrowth was decreased in hsFlt-1-e15a (p = 0.007) and msFlt-1(1-3)-treated (p = 0.02) mice. Full-length msFlt-1-i13 expression was unique for the placenta. In hsFlt-1-e15a-treated mice, the number of pups (p = 0.046), total weight of living pups (p = 0.04) and maternal weights (p = 0.04) were higher than in controls. These differences were not observed in truncated msFlt-1(1-3)-treated mice.

Conclusions: Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1. MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos. In contrast, hsFlt-1-e15a induced preeclampsia-like symptoms; however, it also increased litter size. In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development. These observations point to the difference in the biological effects of full-length and truncated sFlt-1 and the changes in the effect of full-length sFlt-1 during pregnancy, and may have important implications in the management of preeclampsia.

No MeSH data available.


Related in: MedlinePlus

Histopathological evaluation of the kidneys.(A,B,G) Representative H&E (A: Ad-RGD-CMV-GFP, B: Ad-RGD-CYP-GFP) and Jones (G: Ad-RGD-CMV-GFP) stained sections show morphologically normal glomeruli in control animals. (C,D,F,H) Representative H&E (C: Ad-RGD-CMV-sFlt-1-e15a, D: Ad-RGD-CYP-sFlt-1-e15a, F: Ad-CMV-sFlt-1-e15a) and Jones (H: Ad-RGD-CMV-sFlt-1-e15a) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in mice overexpressing sFlt-1-e15a. (E,I) Representative H&E (E) and Jones (I) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in the dam overexpressing msFlt-1(1-3) with chronic hypertension. 400x magnifications. (J) High magnification image (1200x) from sub-image G shows a normal capillary structure. (K) High magnification image (1200x) from sub-image I shows thickened capillary loops. (M) The glomerular damage score was significantly higher in all treatment groups compared to the combined control group. Mice treated with msFlt-1(1-3) had an odds ratio (OR) of 2.4 for glomerular damage (p = 0.01). The OR for glomerular damage was 3.1 in hsFlt-1-e15a-treated mice (2.8×10−5). Among hsFlt-1-e15a-treated mice, mice in the Ad-CMV-hsFlt-1-e15a group had the largest OR (3.9, p = 4.8×10−5) for glomerular damage.
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pone-0110867-g006: Histopathological evaluation of the kidneys.(A,B,G) Representative H&E (A: Ad-RGD-CMV-GFP, B: Ad-RGD-CYP-GFP) and Jones (G: Ad-RGD-CMV-GFP) stained sections show morphologically normal glomeruli in control animals. (C,D,F,H) Representative H&E (C: Ad-RGD-CMV-sFlt-1-e15a, D: Ad-RGD-CYP-sFlt-1-e15a, F: Ad-CMV-sFlt-1-e15a) and Jones (H: Ad-RGD-CMV-sFlt-1-e15a) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in mice overexpressing sFlt-1-e15a. (E,I) Representative H&E (E) and Jones (I) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in the dam overexpressing msFlt-1(1-3) with chronic hypertension. 400x magnifications. (J) High magnification image (1200x) from sub-image G shows a normal capillary structure. (K) High magnification image (1200x) from sub-image I shows thickened capillary loops. (M) The glomerular damage score was significantly higher in all treatment groups compared to the combined control group. Mice treated with msFlt-1(1-3) had an odds ratio (OR) of 2.4 for glomerular damage (p = 0.01). The OR for glomerular damage was 3.1 in hsFlt-1-e15a-treated mice (2.8×10−5). Among hsFlt-1-e15a-treated mice, mice in the Ad-CMV-hsFlt-1-e15a group had the largest OR (3.9, p = 4.8×10−5) for glomerular damage.

Mentions: The kidneys from GFP-treated mice showed widely open capillary loops which had thin delicate walls, and no segmental thickening or hypercellularity was noted (Figure 6A,B). These findings were confirmed using the Jones basement membrane reticulum stain, in which the capillary basement membranes were thin and delicate, and no mesangial thickening was seen (Figure 6G). In contrast, the most consistent histopathological changes seen in the kidneys of mice overexpressing hsFlt-1-e15a or msFlt-1(1-3) were focal and segmental, with swollen capillary endothelial cells, occlusion of glomerular capillaries, and focal mesangial thickening (Figure 6C–F). Scattered glomeruli appeared sclerotic. Glomerular capillary changes were further confirmed by PAS staining and Jones basement membrane reticulum stain, which showed thickened capillary loops and focal expansion of the mesangium (Figure 6H). The dam in the msFlt-1(1-3)-treatment group with the constantly increasing blood pressure had dramatic changes in kidney histology, with extensive glomerular lesions seen in all glomeruli examined. These glomeruli appeared to be somewhat enlarged with marked thickening and expansion of the mesangium, and marked occlusion of capillaries and thickened capillary loops (Figure 6E). In this mouse, Jones basement membrane reticulum stain showed marked thickening and reduplication of the capillary loop basement membranes (Figure 6I). Figure 6K shows severe capillary loop damage with reduplication of the capillary loop in this mouse at high magnification. A normal capillary loop stained with Jones basement membrane reticulum stain is shown in Figure 6J at high magnification.


In vivo experiments reveal the good, the bad and the ugly faces of sFlt-1 in pregnancy.

Szalai G, Xu Y, Romero R, Chaiworapongsa T, Xu Z, Chiang PJ, Ahn H, Sundell B, Plazyo O, Jiang Y, Olive M, Wang B, Jacques SM, Qureshi F, Tarca AL, Erez O, Dong Z, Papp Z, Hassan SS, Hernandez-Andrade E, Than NG - PLoS ONE (2014)

Histopathological evaluation of the kidneys.(A,B,G) Representative H&E (A: Ad-RGD-CMV-GFP, B: Ad-RGD-CYP-GFP) and Jones (G: Ad-RGD-CMV-GFP) stained sections show morphologically normal glomeruli in control animals. (C,D,F,H) Representative H&E (C: Ad-RGD-CMV-sFlt-1-e15a, D: Ad-RGD-CYP-sFlt-1-e15a, F: Ad-CMV-sFlt-1-e15a) and Jones (H: Ad-RGD-CMV-sFlt-1-e15a) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in mice overexpressing sFlt-1-e15a. (E,I) Representative H&E (E) and Jones (I) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in the dam overexpressing msFlt-1(1-3) with chronic hypertension. 400x magnifications. (J) High magnification image (1200x) from sub-image G shows a normal capillary structure. (K) High magnification image (1200x) from sub-image I shows thickened capillary loops. (M) The glomerular damage score was significantly higher in all treatment groups compared to the combined control group. Mice treated with msFlt-1(1-3) had an odds ratio (OR) of 2.4 for glomerular damage (p = 0.01). The OR for glomerular damage was 3.1 in hsFlt-1-e15a-treated mice (2.8×10−5). Among hsFlt-1-e15a-treated mice, mice in the Ad-CMV-hsFlt-1-e15a group had the largest OR (3.9, p = 4.8×10−5) for glomerular damage.
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Related In: Results  -  Collection

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pone-0110867-g006: Histopathological evaluation of the kidneys.(A,B,G) Representative H&E (A: Ad-RGD-CMV-GFP, B: Ad-RGD-CYP-GFP) and Jones (G: Ad-RGD-CMV-GFP) stained sections show morphologically normal glomeruli in control animals. (C,D,F,H) Representative H&E (C: Ad-RGD-CMV-sFlt-1-e15a, D: Ad-RGD-CYP-sFlt-1-e15a, F: Ad-CMV-sFlt-1-e15a) and Jones (H: Ad-RGD-CMV-sFlt-1-e15a) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in mice overexpressing sFlt-1-e15a. (E,I) Representative H&E (E) and Jones (I) stained sections show glomeruli with signs of swollen capillary endothelial cells and occlusion of glomerular capillaries in the dam overexpressing msFlt-1(1-3) with chronic hypertension. 400x magnifications. (J) High magnification image (1200x) from sub-image G shows a normal capillary structure. (K) High magnification image (1200x) from sub-image I shows thickened capillary loops. (M) The glomerular damage score was significantly higher in all treatment groups compared to the combined control group. Mice treated with msFlt-1(1-3) had an odds ratio (OR) of 2.4 for glomerular damage (p = 0.01). The OR for glomerular damage was 3.1 in hsFlt-1-e15a-treated mice (2.8×10−5). Among hsFlt-1-e15a-treated mice, mice in the Ad-CMV-hsFlt-1-e15a group had the largest OR (3.9, p = 4.8×10−5) for glomerular damage.
Mentions: The kidneys from GFP-treated mice showed widely open capillary loops which had thin delicate walls, and no segmental thickening or hypercellularity was noted (Figure 6A,B). These findings were confirmed using the Jones basement membrane reticulum stain, in which the capillary basement membranes were thin and delicate, and no mesangial thickening was seen (Figure 6G). In contrast, the most consistent histopathological changes seen in the kidneys of mice overexpressing hsFlt-1-e15a or msFlt-1(1-3) were focal and segmental, with swollen capillary endothelial cells, occlusion of glomerular capillaries, and focal mesangial thickening (Figure 6C–F). Scattered glomeruli appeared sclerotic. Glomerular capillary changes were further confirmed by PAS staining and Jones basement membrane reticulum stain, which showed thickened capillary loops and focal expansion of the mesangium (Figure 6H). The dam in the msFlt-1(1-3)-treatment group with the constantly increasing blood pressure had dramatic changes in kidney histology, with extensive glomerular lesions seen in all glomeruli examined. These glomeruli appeared to be somewhat enlarged with marked thickening and expansion of the mesangium, and marked occlusion of capillaries and thickened capillary loops (Figure 6E). In this mouse, Jones basement membrane reticulum stain showed marked thickening and reduplication of the capillary loop basement membranes (Figure 6I). Figure 6K shows severe capillary loop damage with reduplication of the capillary loop in this mouse at high magnification. A normal capillary loop stained with Jones basement membrane reticulum stain is shown in Figure 6J at high magnification.

Bottom Line: Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1.MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos.In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development.

View Article: PubMed Central - PubMed

Affiliation: Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, and Detroit, MI, United States of America.

ABSTRACT

Objective: Soluble fms-like tyrosine kinase (sFlt)-1-e15a, a primate-specific sFlt-1-isoform most abundant in the human placenta in preeclampsia, can induce preeclampsia in mice. This study compared the effects of full-length human (h)sFlt-1-e15a with those of truncated mouse (m)sFlt-1(1-3) used in previous preeclampsia studies on pregnancy outcome and clinical symptoms in preeclampsia.

Methods: Mice were injected with adenoviruses or fiber-mutant adenoviruses overexpressing hsFlt-1-e15a, msFlt-1(1-3) or control GFP under the CMV or CYP19A1 promoters on gestational day 8 (GD8) and GD11. Placentas and pups were delivered by cesarean section, and dams were monitored postpartum. Blood pressure was telemetrically recorded. Urine samples were collected with cystocentesis and examined for albumin/creatinine ratios. Tissue specimens were evaluated for transgene as well as endogenous mFlt-1 and msFlt-1-i13 expression. H&E-, Jones- and PAS-stained kidney sections were histopathologically examined. Placental GFP expression and aortic ring assays were investigated with confocal microscopy.

Results: Mean arterial blood pressure (MAP) was elevated before delivery in hsFlt-1-e15a-treated mice compared to controls (GD18: ΔMAP = 7.8 mmHg, p = 0.009), while ΔMAP was 12.8 mmHg (GD18, p = 0.005) in msFlt-1(1-3)-treated mice. Urine albumin/creatinine ratio was higher in hsFlt-1-e15a-treated mice than in controls (GD18, p = 0.04; PPD8, p = 0.03), and msFlt-1(1-3)-treated mice had marked proteinuria postpartum (PPD8, p = 4 × 10(-5)). Focal glomerular changes were detected in hsFlt-1-e15a and msFlt-1(1-3)-treated mice. Aortic ring microvessel outgrowth was decreased in hsFlt-1-e15a (p = 0.007) and msFlt-1(1-3)-treated (p = 0.02) mice. Full-length msFlt-1-i13 expression was unique for the placenta. In hsFlt-1-e15a-treated mice, the number of pups (p = 0.046), total weight of living pups (p = 0.04) and maternal weights (p = 0.04) were higher than in controls. These differences were not observed in truncated msFlt-1(1-3)-treated mice.

Conclusions: Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1. MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos. In contrast, hsFlt-1-e15a induced preeclampsia-like symptoms; however, it also increased litter size. In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development. These observations point to the difference in the biological effects of full-length and truncated sFlt-1 and the changes in the effect of full-length sFlt-1 during pregnancy, and may have important implications in the management of preeclampsia.

No MeSH data available.


Related in: MedlinePlus