Spatiotemporal immunofluorescent evaluation of porcine reproductive and respiratory syndrome virus transmission across the maternal-fetal interface

Suleman, Muhammad; Novakovic, Predrag; Malgarin, Carolina Maciel; Detmer, Susan E.; Harding, John C. S.; MacPhee, Daniel J.

doi:10.1093/femspd/fty060

Cited by 10 publications

(9 citation statements)

References 41 publications

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“…We used tissues collected from a previously described PRRSV challenge experiment, 16,19,23 adhering to principles established by the Canadian Council on Animal Care and approved by the Animal Research Ethics Board at the University of Saskatchewan (Certification 20160023). Briefly, 15 purebred Landrace gilts from a PRRSV-naive farm were experimentally inoculated intranasally and intramuscularly (total dose 1 × 10 5 TCID 50 ) with PRRSV-2 strain NVSL 97-7895 at 86 ± 0.4 d of gestation.…”

Section: Methodsmentioning

confidence: 99%

“…8 The virus replicates in macrophages expressing the CD163 cell surface receptor, 9 and following infection of late-gestation females, viremia and endometritis rapidly develop whereas placentitis and placental detachment develop more slowly. 19 Although the mechanism of in-utero transmission is not understood completely, the virus crosses the placenta within a few days, 23 progressively infecting fetal placenta, umbilical cord, and the fetus. 16…”

Section: Introductionmentioning

confidence: 99%

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Samples sizes required to accurately quantify viral load and histologic lesion severity at the maternal–fetal interface of PRRSV-inoculated pregnant gilts

et al. 2021

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Porcine reproductive and respiratory syndrome virus (PRRSV) is transmitted vertically, causing fetal death in late gestation. Spatiotemporal distribution of virus at the maternal–fetal interface (MFI) is variable, and accurate assessment of viral concentration and lesions is thus subject to sampling error. Our objectives were: 1) to assess whether viral load and lesion severity in a single sample of endometrium (END) and placenta (PLC), collected near the base of the umbilical cord (the current standard), are representative of the entire organ; and 2) to compare sampling strategies and evaluate if spatial variation in viral load can be overcome by pooling of like-tissues. Spatially distinct pieces of END and PLC of 24 fetuses from PRRSV-2–infected dams were collected. PRRSV RNA quantified by RT-qPCR was compared in 5 individual pieces per fetus and in respective pools of tissue and extracted RNA. Three distinct pieces of MFI were assessed for histologic severity. Concordance correlation and kappa inter-rater agreement were used to characterize agreement among individual samples and pools. The viral load of individual samples and pools of END had greater concordance to a referent standard than did samples of PLC. Larger pool sizes had greater concordance than smaller pool sizes. Average viral load and lesion severity did not differ by location sampled, and no technical advantages of pooling tissues versus RNA extracts were found. We conclude that multiple pieces of MFI tissues must be evaluated to accurately assess lesion severity and viral load. Three pieces per fetus provided a reasonable balance of cost and logistic feasibility.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Samples sizes required to accurately quantify viral load and histologic lesion severity at the maternal–fetal interface of PRRSV-inoculated pregnant gilts

et al. 2021

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“…Porcine reproductive and respiratory syndrome (PRRS) is a financially devastating Arteriviral disease (Holtkamp et al, 2013) associated with systemic vasculitis, immunosuppression, and persistent infections in post-natal pigs. Infection of pregnant sows or gilts during the third trimester results in rapid endometritis and endometrial vasculitis (Novakovic et al, 2018) followed by rapid transmission across the diffuse epitheliochorial placenta within days of maternal infection (Suleman et al, 2018;Malgarin et al, 2019). Fetal infection FIGURE 1 | Metabolite profiles of four disease progression fetal phenotypes.…”

Section: Introductionmentioning

confidence: 99%

Fetal Metabolomic Alterations Following Porcine Reproductive and Respiratory Syndrome Virus Infection

Malgarin

MacPhee

Harding

2020

Front. Mol. Biosci.

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PRRSV infection in third-trimester pregnant sows can lead to fetal death and abortions, although the mechanisms triggering these effects are not well understood. Since resistant and susceptible fetuses can coexist in the same litter, we propose that there may be differential mechanisms used by some fetuses to evade infection and/or disease progression. Our objectives were to investigate possible differences in the metabolome of PRRSV-infected and non-infected fetuses, as well as the interaction of altered intrauterine growth development and PRRSV infection to elucidate possible causes of fetal death following PRRSV infection. Near-term serum samples collected from fetuses on gestation day 106, 21 days post PRRSV-2 infection, were processed by direct flow injection mass spectrometry (DI-MS) and nuclear magnetic resonance (NMR) techniques. Experiment one investigated disease progression with 24 fetuses selected from each of four phenotypic groups: fetuses from non-inoculated gilts (CTRL); fetuses from inoculated gilts that escaped infection (UNINF); infected high viral load viable fetuses (INF); and infected high viral load meconium-stained fetuses (MEC). Experiment two investigated the interaction of intrauterine growth retardation (IUGR) and PRRSV infection by analyzing differences among: non-infected normal development (CON-N); CON-IUGR; PRRS infected normal development (PRRS-N); and PRRS-IUGR. Univariate and multivariate (PCA, PLS-DA) statistics determined group differences among various contrasts, and the most important metabolites associated with disease progression and fetal development. Significant differences in the metabolome were observed, especially between PRRSV-negative fetuses (CTRL and UNINF) and MEC fetuses, while INF fetuses appear to span both groups. The two metabolites with highest variable importance in projection (VIP) scores related to disease progression were alpha-aminoadipic acid (alpha-AAA) and kynurenine (KYN), having the highest concentration in MEC and INF fetuses, respectively, compared to CTRL and UNINF. In experiment two, non-IUGR fetuses were found to have increased levels of lysoPCs, PCs and amino acids compared to IUGR fetuses, while the near complete absence of lysoPCs and PCs in IUGR fetuses, even during infection, indicate a distinctive response to infection compared to non-growth retarded fetuses. Possible markers of PRRSV fetal susceptibility, such as alpha-AAA, kynurenine and lysoPCs, are presented and discussed.

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“…Three size categories were established: “large foci” above 23 μm 2 ; “medium foci” between 5 and 23 μm 2 ; and “small foci” below 5 μm 2 . The “small foci” category was removed from further analyses because they were considered artifacts, or not related to cell-associated PRRSV infection, as PRRSV infection is restricted to porcine alveolar macrophages or differentiated blood monocytes [ 40 ], which measure between 15 and 20 μm [ 5 ]. Data was tested for normality using the Shapiro-Wilk test.…”

Section: Methodsmentioning

confidence: 99%

“…The mechanisms of fetal disease are not entirely understood and few studies have explored this topic, in part due to the lack of obvious fetal lesions [ 3 , 4 ]. Following maternal infection, PRRSV rapidly infects the endometrium and crosses the epitheliochorial placenta to the fetus [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Fetal hypoxia and apoptosis following maternal porcine reproductive and respiratory syndrome virus (PRRSV) infection

Malgarin¹,

Moser²,

Pasternak

et al. 2021

BMC Vet Res

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Background Mechanisms of fetal death following maternal PRRSV2 infection remain uncharacterized, although hypoxia from umbilical cord lesions and/or placental detachment due to apoptosis are hypothesized. We performed two experiments examining hypoxia and apoptosis in PRRSV-infected and non-infected, third-trimester fetuses to elucidate possible associations with fetal death. Fetuses were selected based on four phenotypic infection groups: fetuses from non-challenged control gilts (CTRL); low viral load fetuses (LVL; Exp 1) or uninfected fetuses (UNINF; Exp 2) from inoculated gilts; viable high viral load fetuses (HVL-VIA); and HVL meconium-stained fetuses (HVL-MEC). Results In experiment 1, paraffin embedded fetal tissues collected 21 days post maternal infection (DPI) were examined for DNA fragmentation associated with apoptosis. Positively stained foci were larger and more numerous (P < 0.05) in heart, liver, and thymus of HVL-VIA and HVL-MEC compared to CTRL and LVL fetuses. In experiment 2, group differences in gene expression within the hypoxia (HIF1a, IDO1, VEGFa, LDHA, NOS2, NOX1) and apoptosis (CASP3, CASP7, CASP8, CASP9, RIPK1, RIPK3) pathways were assessed by RT-qPCR in fetal tissues collected at 12 DPI. High viral load fetuses showed differential expression relative to the CTRL and UNINF (P < 0.05 for all). Brain tissue from HVL-VIA and HVL-MEC fetuses presented increased expression of CASP7, CASP8, RIPK3, HIF1a and IDO1. Fetal heart showed increased expression of CASP8, HIF1a, IDO and NOX1 and a decrease in NOS2 expression in infected groups. CASP7, CASP9, RIPK1 and RIPK3 were only increased in the heart of HVL-VIA while VEGFa was only increased for HVL-MEC fetuses. Thymus from HVL-MEC had decreased expression of CASP9 and there was increased IDO1 in all infected fetuses. Conclusions There is strong evidence of apoptosis occurring in the heart, liver and thymus of highly viral load fetuses at 21 DPI. Furthermore, there was clear upregulation of apoptotic genes in the heart of high viral load infected fetuses and less prominent upregulation in the brain of PRRSV-infected fetuses, whereas thymus appears to be spared at 12 DPI. There was no strong evidence of hypoxia at 12 DPI in brain and thymus but some indication of hypoxia occurring in fetal heart.

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Spatiotemporal immunofluorescent evaluation of porcine reproductive and respiratory syndrome virus transmission across the maternal-fetal interface

Cited by 10 publications

References 41 publications

Samples sizes required to accurately quantify viral load and histologic lesion severity at the maternal–fetal interface of PRRSV-inoculated pregnant gilts

Samples sizes required to accurately quantify viral load and histologic lesion severity at the maternal–fetal interface of PRRSV-inoculated pregnant gilts

Fetal Metabolomic Alterations Following Porcine Reproductive and Respiratory Syndrome Virus Infection

Fetal hypoxia and apoptosis following maternal porcine reproductive and respiratory syndrome virus (PRRSV) infection

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