Fatty acid uptake, transport and storage in placenta in normal and dyslipidemic pregnancies

Transport of fatty acids across the placenta is vital for growth and development of the fetus. The placenta also plays an essential role in the development of preeclampsia, a disease associated with dyslipidemia, oxidative stress and inflammation. This thesis investigates the role of trophoblasts and placenta in lipid transport and storage in general, and in dyslipidemic pregnancies specifically. The transport and uptake of fatty acids across trophoblast cells were studied in a placental cell line (BeWo). It was found that long-chain polyunsaturated fatty acids (LCPUFAs) are more efficiently transferred across these cells, and long term incubation with these fatty acids increases the general uptake of fatty acids compared with oleic acid. This suggests that LCPUFAs may function as regulators of fatty acid uptake by trophoblasts, which could have important implications for fetal nutrition and placental function. The expression of several genes involved in fatty acid uptake and metabolism were analyzed. The expression of long-chain acyl-CoA synthetases (ACSL1 and 5) and the lipid droplet associated protein ADRP was increased by LCPUFAs, suggesting that these genes may be involved in the enhanced uptake of fatty acids mediated by LCPUFAs. Expression of these genes was also investigated in placenta from women with healthy pregnancies or preeclampsia. The expression of the transcription factor LXR, an important regulator of lipid metabolism, was decreased in preeclamptic placenta. ADRP was increased in preeclamptic placenta. ADRP expression in BeWo cells was increased by fatty acids (those elevated in the maternal circulation in preeclampsia) and by agents inducing oxidative stress. This suggests that placental ADRP could be regulated by both dyslipidemia and oxidative stress, and implies a role for ADRP in preeclamptic pregnancies. However, the exact function of ADRP and lipid droplets in placenta needs to be explored further

Pregnancy and postpartum levels of circulating maternal sHLA-G in preeclampsia

Preeclampsia is a leading cause of maternal and offspring mortality and morbidity, and predicts increased future cardiovascular disease risk. Placental dysfunction and immune system dysregulation are likely key pathophysiological factors. Soluble human leukocyte antigen G (sHLA-G) may dampen the specific immune response towards placental trophoblasts. Previous studies have shown low sHLA-G levels in preeclampsia, but postpartum, levels are unknown. Furthermore, the relationship between sHLA-G and sFlt-1 and PlGF, placental function markers, is unknown. We hypothesized that low maternal sHLA-G during pregnancy would be associated with placental dysfunction, including preeclampsia, gestational hypertension, and dysregulated sFlt-1 and PlGF, and that sHLA-G would remain decreased following preeclampsia. We included 316 pregnant women: 58 with early-onset preeclampsia (<34 weeks’ gestation), 81 with late-onset preeclampsia (≥34 weeks’ gestation), 25 with gestational hypertension, and 152 normotensive controls. Postpartum (1 or 3 years), we included 321 women: 29 with early-onset preeclampsia, 98 with late-onset preeclampsia, 57 with gestational hypertension, and 137 who were normotensive during their index pregnancies. In pregnancy, plasma sHLA-G was significantly lower both in the early- and late-onset preeclampsia groups compared to controls. In women with preeclampsia or gestational hypertension, sHLA-G was inversely correlated with serum sFlt-1. Postpartum, plasma sHLA-G levels were significantly higher in women who had had early-onset preeclampsia compared to controls. Our results support that sHLA-G may be important for placental function. Unexpectedly, sHLA-G was elevated up to 3 years after early-onset preeclampsia, suggesting an excessively activated immune system following this severe preeclampsia form, potentially contributing to future cardiovascular disease risk

Lymphocyte characterization of decidua basalis spiral arteries with acute atherosis in preeclamptic and normotensive pregnancies

Uteroplacental acute atherosis (AA) is a common spiral arterial lesion in preeclampsia, characterized by intramural foam cells, fibrinoid necrosis, and a perivascular immune cell infiltrate. A clear definition of this infiltrate is lacking. Therefore, our aim was to characterize lymphocytes in pre-defined zones regarding spiral arteries with or without AA, from preeclamptic and normotensive pregnancies. Lymphocytes were characterized in decidua basalis samples (n = 91), previously evaluated for AA, around spiral arteries in three pre-defined zones; 1) intramural, 2) perivascular and 3) interstitial. Adjacent serial sections were immunostained to identify different T-cell populations (CD3+, CD8+, FOXP3+), and NK-cells (CD56+). CD3+CD8- T-cells were also identified. These were presumed to be largely CD4+ T-cells. AA was associated with significantly higher intramural CD3+ cell concentrations in Zone 1, in both normotensives and preeclamptics. In preeclamptics only, this difference extended into Zone 2. Similar results were observed for CD3+CD8- cells. AA was also associated with increased intramural CD8+ concentration; however, the number of cells was low. Regulatory T-cells (FOXP3+) were generally scarce or absent in all pre-defined zones. Although intramural NK-cells (CD56+) were scarce, the intramural concentration was significantly lower in spiral arteries with AA compared to without AA in preeclamptics. Our main finding was that CD3+CD8-FoxP3- T-cells were associated with AA. We therefore suggest that T-cells, of a non-regulatory CD4+ subtype, could be involved in the formation of spiral artery AA in the decidua basalis. Whether AA gives rise to, or is partly mediated by increased T-cell concentration around the lesions, remains to be determined

Classical cardiovascular risk markers in pregnancy and associations to uteroplacental acute atherosis

Uteroplacental acute atherosis (AA) is a pregnancy-specific arterial lesion resembling early stages of atherosclerosis. AA is frequent in preeclamptic pregnancies, which associate with increased long-term maternal risk of atherosclerotic cardiovascular disease. We hypothesized that AA in pregnant women associates with classical risk factors for cardiovascular disease, including hypertension, hyperlipidemia, glucose intolerance, elevated C-reactive protein, age, and body mass index. We included 237 women delivered by cesarean section (healthy pregnancies, n=94; preeclampsia, n=87; pregestational and gestational diabetes mellitus, n=39; diabetes mellitus with preeclampsia, n=17). They provided blood before delivery for biomarker analyses. AA was diagnosed by immunohistochemistry in uteroplacental (decidual) tissue collected after placental removal. Statistical analyses were performed with Mann-Whitney test. Levels of traditional cardiovascular markers were not associated with decidual AA within the groups of women with normotensive pregnancies, preeclampsia, diabetes mellitus, or diabetes mellitus superimposed with preeclampsia. However, the oldest patient age quartile (36–43 years old) with AA had significantly higher levels of LDL (low-density lipoprotein) and apolipoprotein B (both P<0.01) than women of the same age without AA. AA was associated with elevated median prepregnancy/early pregnancy systolic blood pressure (P=0.01) in the total cohort, but as preeclampsia was strongly associated with this finding (P<0.01), this was likely caused by a large proportion of preeclamptic pregnancies in the AA group (62.7%). Our findings demonstrate that dyslipidemia associated with cardiovascular risk is a feature of uteroplacental AA in older women, not of AA in pregnancy in general

Acute Atherosis Lesions at the Fetal-Maternal Border: Current Knowledge and Implications for Maternal Cardiovascular Health

Decidua basalis, the endometrium of pregnancy, is an important interface between maternal and fetal tissues, made up of both maternal and fetal cells. Acute atherosis is a uteroplacental spiral artery lesion. These patchy arterial wall lesions containing foam cells are predominantly found in the decidua basalis, at the tips of the maternal arteries, where they feed into the placental intervillous space. Acute atherosis is prevalent in preeclampsia and other obstetric syndromes such as fetal growth restriction. Causal factors and effects of acute atherosis remain uncertain. This is in part because decidua basalis is challenging to sample systematically and in large amounts following delivery. We summarize our decidua basalis vacuum suction method, which facilitates tissue-based studies of acute atherosis. We also describe our evidence-based research definition of acute atherosis. Here, we comprehensively review the existing literature on acute atherosis, its underlying mechanisms and possible short- and long-term effects. We propose that multiple pathways leading to decidual vascular inflammation may promote acute atherosis formation, with or without poor spiral artery remodeling and/or preeclampsia. These include maternal alloreactivity, ischemia-reperfusion injury, preexisting systemic inflammation, and microbial infection. The concept of acute atherosis as an inflammatory lesion is not novel. The lesions themselves have an inflammatory phenotype and resemble other arterial lesions of more extensively studied etiology. We discuss findings of concurrently dysregulated proteins involved in immune regulation and cardiovascular function in women with acute atherosis. We also propose a novel hypothesis linking cellular fetal microchimerism, which is prevalent in women with preeclampsia, with acute atherosis in pregnancy and future cardiovascular and neurovascular disease. Finally, women with a history of preeclampsia have an increased risk of premature cardiovascular disease. We review whether presence of acute atherosis may identify women at especially high risk for premature cardiovascular disease

HLA-G whole gene amplification reveals linkage disequilibrium between the HLA-G 3′UTR and coding sequence

Polymorphic sites in the HLA‐G gene may influence expression and function of the protein. Knowledge of the association between high‐resolution HLA‐G alleles and 3‐prime untranslated (3′UTR) haplotypes is useful for studies on the role of HLA‐G in transplantation, pregnancy, and cancer. We developed a next generation sequencing (NGS)‐based typing assay enabling full phasing over the whole HLA‐G gene sequence with inclusion of the 3′UTR region. DNA from 171 mother‐child pairs (342 samples) was studied for: (a) HLA‐G allele information by the NGSgo‐AmpX HLA‐G assay, (b) 3′UTR haplotype information by an in‐house developed sequence‐based typing method of a 699/713 base pair region in the 3′UTR, and (c) the full phase HLA‐G gene sequence, by combining primers from both assays. The mother to child inheritance allowed internal verification of newly identified alleles and of association between coding and UTR regions. The NGSgo workflow compatible with Illumina platforms was employed. Data was interpreted using NGSengine software. In 99.4% of all alleles analyzed, the extended typing was consistent with the separate allele and 3′UTR typing methods. After repeated analysis of four samples that showed discrepancy, consistency reached 100%. A high‐linkage disequilibrium between IPD‐IMGT/HLA Database‐defined HLA‐G alleles and the extended 3′UTR region was identified (D′ = 0.994, P < .0001). Strong associations were found particularly between HLA‐G*01:04 and UTR‐3, between HLA‐G*01:01:03 and UTR‐7, and between HLA‐G*01:03:01 and UTR‐5 (for all: r = 1). Six novel HLA‐G alleles and three novel 3′UTR haplotype variants were identified, of which three and one, respectively, were verified in the offspring