Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Feb 13;3(2):e1608.
doi: 10.1371/journal.pone.0001608.

Pregnancy outcome and placenta pathology in Plasmodium berghei ANKA infected mice reproduce the pathogenesis of severe malaria in pregnant women

Rita Neres  1 , Claudio R F Marinho, Lígia A Gonçalves, Manuela Beirão Catarino, Carlos Penha-Gonçalves
Affiliations

Pregnancy outcome and placenta pathology in Plasmodium berghei ANKA infected mice reproduce the pathogenesis of severe malaria in pregnant women

Rita Neres et al. PLoS One. .

Abstract

Pregnancy-associated malaria (PAM) is expressed in a range of clinical complications that include increased disease severity in pregnant women, decreased fetal viability, intra-uterine growth retardation, low birth weight and infant mortality. The physiopathology of malaria in pregnancy is difficult to scrutinize and attempts were made in the past to use animal models for pregnancy malaria studies. Here, we describe a comprehensive mouse experimental model that recapitulates many of the pathological and clinical features typical of human severe malaria in pregnancy. We used P. berghei ANKA-GFP infection during pregnancy to evoke a prominent inflammatory response in the placenta that entails CD11b mononuclear infiltration, up-regulation of MIP-1 alpha chemokine and is associated with marked reduction of placental vascular spaces. Placenta pathology was associated with decreased fetal viability, intra-uterine growth retardation, gross post-natal growth impairment and increased disease severity in pregnant females. Moreover, we provide evidence that CSA and HA, known to mediate P. falciparum adhesion to human placenta, are also involved in mouse placental malaria infection. We propose that reduction of maternal blood flow in the placenta is a key pathogenic factor in murine pregnancy malaria and we hypothesize that exacerbated innate inflammatory responses to Plasmodium infected red blood cells trigger severe placenta pathology. This experimental model provides an opportunity to identify cell and molecular components of severe PAM pathogenesis and to investigate the inflammatory response that leads to the observed fetal and placental blood circulation abnormalities.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Increased disease susceptibility in pregnant BALB/c mice infected with P. berghei-GFP.
BALB/c pregnant females were infected on G13 by IV injection of 106 iRBC and non-pregnant females were simultaneously infected. The plots represent cumulative results of three independent experiments in a total of 32 pregnant and 16 non-pregnant females. (A) Parasitemia curves where data points represent mean±SE. From day 3 post-infection onwards parasitemia was significantly higher in pregnant females (P-value<0.05). (B) Survival curves up to 10 days after infection show that survival time of pregnant female mice are significantly lower than in controls (P-value<0.0001). It should be noted that non-pregnant females died at a later stage with hyperparasitemia.
Figure 2
Figure 2. Reduced growth rate in progenies of P. berghei-GFP infected mothers.
BALB/c pregnant females were infected on G13 by IV injection of 106 iRBC. After delivery newborns were transferred to a foster mother and their body weight was followed up to weaning (A). Example of body size difference at day 21 of age is shown in (B), mouse born from non-infected (left side) and from infected mother (right side).
Figure 3
Figure 3. P. berghei-GFP infection impairs pregnancy outcome and fetus development.
(A) Representative uterus at G18 from BALB/c pregnant females, uninfected (upper) and infected on G13 with P. berghei-GFP by IV injection of 106 iRBC (bottom). The arrowheads indicate abortions. (B) Fetus from uninfected (left) and from infected mother (right). In detail, mouse placenta from an uninfected (C) and infected mother (D). Lack of blood circulation is noticeable in the placenta, paws and tail in panel (D). Scale bar represents 1 cm in A–B and 0.5 cm in C–D.
Figure 4
Figure 4. Placenta pathology in infected pregnant mice.
Histology of infected placentas collected at G18. HE stained sections from non-infected mice (panels A and C) and infected (panels B and D) are depicted. Different cell types are identified in panel A as (DC) decidual cells, (Cy) cytotrophoblastic cells and (La) labyrinthic cells. Fibrinoid necrosis areas (Ne) are indicated in panel B. Arrowhead in D shows syncytiotrophoblast tissue thickening. Scale bar represents 100 μm in (A–B), and 10 μm in (C–D).
Figure 5
Figure 5. Placental malaria.
HE stained placentas from BALB/c females infected with P. berghei-GFP and collected at G18. (A) Image from severely infected placenta with high number of parasitized maternal erythrocytes. (B) The same field as (A) under polarization microscopy revealing hemozoin parasite pigment. (C) Arrowhead and insert show an infected erythrocyte adhered to the syncytiotrophoblast layer. (D) Placental section with infected erythrocytes (arrowhead) in the maternal blood and fetal erythroblasts that were enhanced in the insert. Scale bar represents 30 μm in (A, B and D) and 20 μm in (C).
Figure 6
Figure 6. Inflammatory infiltration and macrophage/monocyte attractant chemokine expression in malaria infected placenta.
(A) Immunohistochemistry analysis of placentas from BALB/c females infected on G13 with P. berghei-GFP iRBC and collected at G18 that were stained with anti-GFP (green) and anti-CD11b (red) revealing the presence of parasites on vascular walls and monocytes/macrophages infiltration, respectively. The (B) panel represents sections of non infected placentas. The cell nuclei were stained with DAPI (blue). Scale bar represents 30 μm. (C) RNA expression of MIP-1 alpha and MCP-1 genes were quantified in 30 infected and 8 uninfected BALB/c placentas collected on G18. Relative quantification was obtained by normalization for GAPDH expression. Each bar represents the mean±standard error of individual values. P-value = 0.0002 is represented by ***.
Figure 7
Figure 7. Reduction of placental vascular space in infected pregnant mice.
(A) The available area for blood circulation at G18 is reduced in the case of infected placentas (A, right) in comparison with non-infected (A, left). Scale bar represents 25 μm. (B) The placental area occupied by blood sinusoids was quantified in relation to the total placental area using an automated morphometric procedure, as described in Materials and Methods (p<0.001, Mann Whitney Test).
Figure 8
Figure 8. Ex vivo adherence of P. berghei-GFP iRBC to mouse placenta.
(A) Typical microscopic image of adherence assays showing iRBC adhered in the intervillous space and to syncytiotrophoblast cell layer (A). Representative images of blocking adherence assays where iRBC were pre-incubated with 2 mg/ml of CSA (B) and HA (C). IRBC were preincubated with increasing concentrations of HA, CSA and colominic acid and then used in binding assays as described in materials and methods (D, upper graph). Adhesion of iRBC to uninfected placental tissue pre-treated with chondroitinase ABC and hyaluronidase but not with heparinase (D, middle graph). Intact iRBC were treated with neuraminidase, proteinase K and trypsin prior incubation with the placental tissue (D, lower graph). All data represent the proportion of bound iRBC expressed as a percentage of control (mean±s.e.m. for three experiments). P-value<0.001 is represented by ***.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Steketee RW, Nahlen BL, Parise ME, Menendez C. The burden of malaria in pregnancy in malaria-endemic areas. Am J Trop Med Hyg. 2001;64:28–35. - PubMed
    1. Desai M, ter Kuile FO, Nosten F, McGready R, Asamoa K, et al. Epidemiology and burden of malaria in pregnancy. Lancet Infect Dis. 2007;7:93–104. - PubMed
    1. Menendez C. Malaria during pregnancy: a priority area of malaria research and control. Parasitol Today. 1995;11:178–183. - PubMed
    1. Nosten F, Rogerson SJ, Beeson JG, McGready R, Mutabingwa TK, et al. Malaria in pregnancy and the endemicity spectrum: what can we learn? Trends Parasitol. 2004;20:425–432. - PubMed
    1. Shulman CE, Graham WJ, Jilo H, Lowe BS, New L, et al. Malaria is an important cause of anaemia in primigravidae: evidence from a district hospital in coastal Kenya. Trans R Soc Trop Med Hyg. 1996;90:535–539. - PubMed

Publication types