| 1. |
- Schneider, Henning, et al.
(författare)
-
Ex vivo dual perfusion of an isolated human placenta cotyledon : Towards protocol standardization and improved inter-centre comparability
- 2022
-
Ingår i: Placenta. - : Elsevier BV. - 0143-4004. ; 126, s. 83-89
-
Tidskriftsartikel (refereegranskat)abstract
- Since the full development of the ex vivo dual perfusion model of the human placenta cotyledon, the technique has provided essential insight into how nutrients, lipids, gases, immunoglobulins, endocrine agents, pharmaceuticals, chemicals, nanoparticles, micro-organisms and parasites might traverse the maternofetal barrier. Additionally, the model has been instrumental in gaining a better understanding of the regulation of vascular tone, endocrinology and metabolism within this organ. The human placenta is unique amongst species in its anatomy and transfer modalities. This orthologous diversity therefore requires an appropriate consideration of placental transfer rates of compounds, particles and micro-organisms specific to humans. Different research centres have adapted this model with a wide variation in perfusion parameters, including in the establishment of perfusion, perfusate composition, gassing regime, cannulation method, flow rates, perfused tissue mass, and also in the application of quality control measures. The requirement to harmonise and standardise perfusion practice between centres is largely driven by the need to obtain consistency in our understanding of placental function, but also in the qualification of the model for acceptance by regulatory agencies in drug and toxicology testing. A pilot study is proposed, aiming to describe how existing inter-centre variation in perfusion methodology affects placental metabolism, protein synthesis, oxygen consumption, the materno-fetal transfer of key molecular markers, and placental structure.
|
|
| 2. |
- Abelius, Martina, et al.
(författare)
-
Placental immune response to apple allergen in allergic mothers
- 2014
-
Ingår i: Journal of Reproductive Immunology. - : Elsevier. - 0165-0378 .- 1872-7603. ; 106, s. 100-109
-
Tidskriftsartikel (refereegranskat)abstract
- The immunological milieu in the placenta may be crucial for priming the developing foetal immune system. Early imbalances may promote the establishment of immune-mediated diseases in later life, including allergies. The initial exposure to allergens seems to occur in utero, but little is known about allergen-induced placental cytokine and chemokine release. The release of several cytokines and chemokines from placenta tissue after exposure to mast cell degranulator compound 48/80 or apple allergen in placentas from allergic and healthy mothers was to be analysed. Four placentas from women with apple allergy and three controls were applied in a placental perfusion model with two separate cotyledons simultaneously perfused with and without apple allergen (Mal d 1). Two control placentas were perfused with compound 48/80. In outflow, histamine was quantified spectrophotofluorometrically, IL-2, IL-4, IL-6, IL-10, TNF and IFN-gamma by a cytometric multiplex bead array and IL-13 and CXCL10, CXCL11, CCL17 and CCL22 with an in-house multiplex Luminex assay. Compound 48/80 induced a rapid release of histamine, CXCL10, CXCL11, CCL17 and CCL22, but not of the other factors. Apple allergen induced a time-dependent release of IL-6 and TNF, but not of histamine, in placentas of women with apple allergy compared with the unstimulated cotyledon. CCL17 levels were slightly increased after allergen stimulation in control placentas. Allergens can induce placental cytokines and chemokines distinctly in allergic and healthy mothers. These mediators may affect the prenatal development of the immune system and modify the risk of diseases related to immune disorders in childhood such as allergies.
|
|
| 3. |
- Brownbill, Paul, et al.
(författare)
-
An international network (PlaNet) to evaluate a human placental testing platform for chemicals safety testing in pregnancy
- 2016
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238. ; 64, s. 191-202
-
Tidskriftsartikel (refereegranskat)abstract
- The human placenta is a critical life-support system that nourishes and protects a rapidly growing fetus; a unique organ, species specific in structure and function. We consider the pressing challenge of providing additional advice on the safety of prescription medicines and environmental exposures in pregnancy and how ex vivo and in vitro human placental models might be advanced to reproducible human placental test systems (HPTSs), refining a weight of evidence to the guidance given around compound risk assessment during pregnancy. The placental pharmacokinetics of xenobiotic transfer, dysregulated placental function in pregnancy-related pathologies and influx/efflux transporter polymorphisms are a few caveats that could be addressed by HPTSs, not the specific focus of current mammalian reproductive toxicology systems. An international consortium, “PlaNet”, will bridge academia, industry and regulators to consider screen ability and standardisation issues surrounding these models, with proven reproducibility for introduction into industrial and clinical practice.
|
|
| 4. |
- Bruno, Valentina, 1986-
(författare)
-
Clinical and immunological aspects on recurrent pregnancy loss
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Paper I. Effects of low molecular weight heparin on the polarization and cytokine profile of macrophages and T helper cells in vitro. Sci Rep 2018. In paper I low molecular weight heparin (LMWH) in vitro effects on activation and polarization of central regulatory immune cells, such as Th cells and macrophages, were assessed, since LMWH has been widely used as an empiric treatment in recurrent pregnancy loss (RPL) and its immunological effects are not fully known. Isolated blood monocytes and T helper (Th) cells under different activation and polarizing conditions were cultured without or with LMWH at different concentrations. LMWH exposure induced an activated phenotype of macrophages, with high expression of HLA-DR and CD206 assessed by flow cytometry, associated with increased secretion of Th17-associated CCL20, and decreased secretion of CCL2 (M2-associated) and CCL22 (Th2), as measured by multiplex bead array. In accordance, LMWH exposure to Th cells reduced the proportion of CD25highFoxp3+ regulatory Tcells, and intensified IFN-γ secretion. Collectively, a mainly pro-inflammatory effect was noted on two essential tolerance-promoting cells, suggesting that potential immunological effects of LMWH may be effective mainly at an earlier gestational age to provide an appropriate implantation process in women with recurrent miscarriage. Paper II. Low-molecular-weight-heparin increases Th1- and Th17-associated chemokine levels during pregnancy in women with unexplained recurrent pregnancy loss: a randomized controlled trial. Sci Rep 2019.In paper II we investigated whether LMWH could modulate immune responses in vivo during pregnancy of women with unexplained RPL. A Swedish open multi-centre randomized controlled trial included 45 women treated with tinzaparin and 42 untreated women. Longitudinally collected plasma samples were obtained at gestational weeks (gw) 6, 18, 28 and 34 and analyzed by multiplex bead technology for levels of 11 cytokines and chemokines, chosen to represent inflammation and T-helper subset-associated immunity. LMWH-treated and untreated women showed differences during pregnancy of the Th1-associated chemokines CXCL10 (p = 0.01), CXCL11 (p < 0.001) and the Th17- associated chemokine CCL20 (p = 0.04), while CCL2, CCL17, CCL22, CXCL1, CXCL8, CXCL12, CXCL13 and IL-6 did not differ. Significantly higher plasma levels of CXCL10 and CXCL11 in treated women were detected at gw 28 and 34, compared to the untreated ones. Thus, a potential proinflammatory effect, linked mainly to Th1 immunity, was shown, suggesting an unfavorable effect of LMWH treatment, since Th1 responsea are responsible for breaking the fetal-maternal immune tolerance. Paper III. First-trimester trophoblasts obtained by chorionic villus sampling maintain tolerogenic and proteomic features in successful pregnancies despite a history of unexplained recurrent pregnancy loss. Am J Reprod Immunol. 2020.In paper III we investigate the “local” immune changes in women with RPL, since they potentially could reveal important mechanisms in RPL. Supernatants from superfluous chorionic villus sampling material culture was used in an ex vivo model, to determinate the immune proteomics profile and to perform functional assays for M2 like macrophages and regulatory T cells polarization, assessed by flow cytometry technique. Chorionic villi, human fetally derived placental tissue, were shown to induce an M2 like-phenotype and an expansion of Treg cells in an ex vivo model, and these immunological properties were maintained despite a history of RPL. Accordingly, no differences in the inflammation proteomic profile were found in RPL, compared to controls. Trophoblasts in an ex vivo model thus maintain tolerogenic and proteomic profile features in successful pregnancies, despite a history of RPL.
|
|
| 5. |
- Buse, Eberhard, et al.
(författare)
-
The placenta in toxicology. Part I : Animal models in toxicology
- 2014
-
Ingår i: Toxicologic pathology (Print). - : Sage Publications. - 0192-6233 .- 1533-1601. ; 42:2, s. 314-326
-
Forskningsöversikt (refereegranskat)abstract
- The immune system represents a key defense mechanism against potential pathogens and adverse non-self materials. During pregnancy, the placenta is the point of contact between the maternal organism and non-self proteins of the fetal allograft and hence undoubtedly fulfils immune functions. In the placenta bacteria, foreign (non-self) proteins and proteins that might be introduced in toxicological studies or by medication are barred from reaching the progeny, and the maternal immune system is primed for acceptance of non-maternal fetal protein. Both immunologic protection of the fetus and acceptance of the fetus by the mother require effective mechanisms to prevent an immunologic fetomaternal conflict and to keep both organisms in balance. This is why the placenta requires toxicological consideration in view of its immune organ function. The following articles deal with placenta immune-, control-, and tolerance mechanisms in view of both fetal and maternal aspects. Furthermore, models for experimental access to placental immune function are addressed and the pathological evaluation is elucidated. "The Placenta as an Immune Organ and Its Relevance in Toxicological Studies" was subject of a continuing education course at the 2012 Society of Toxicologic Pathology meeting held in Boston, MA.
|
|
| 6. |
- Cline, J Mark, et al.
(författare)
-
The placenta in toxicology. Part III : Pathologic assessment of the placenta
- 2014
-
Ingår i: Toxicologic pathology (Print). - : Sage Publications. - 0192-6233 .- 1533-1601. ; 42:2, s. 339-344
-
Tidskriftsartikel (refereegranskat)abstract
- This short review is derived from the peer-reviewed literature and the experience and case materials of the authors. Brief illustrated summaries are presented on the gross and histologic normal anatomy of rodent and macaque placentas, including typical organ weights, with comments on differences from the human placenta. Common incidental findings, background lesions, and induced toxic lesions are addressed, and a recommended strategy for pathologic evaluation of placentas is provided.
|
|
| 7. |
- Göhner, Claudia, et al.
(författare)
-
The placenta in toxicology. Part IV : Battery of toxicological test systems based on human placenta
- 2014
-
Ingår i: Toxicologic pathology (Print). - : Sage Publications. - 0192-6233 .- 1533-1601. ; 42:2, s. 345-351
-
Tidskriftsartikel (refereegranskat)abstract
- This review summarizes the potential and also some limitations of using human placentas, or placental cells and structures for toxicology testing. The placenta contains a wide spectrum of cell types and tissues, such as trophoblast cells, immune cells, fibroblasts, stem cells, endothelial cells, vessels, glands, membranes, and many others. It may be expected that in many cases the relevance of results obtained from human placenta will be higher than those from animal models due to species specificity of metabolism and placental structure. For practical and economical reasons, we propose to apply a battery of sequential experiments for analysis of potential toxicants. This should start with using cell lines, followed by testing placenta tissue explants and isolated placenta cells, and finally by application of single and dual side ex vivo placenta perfusion. With each of these steps, the relative workload increases while the number of feasible repeats decreases. Simultaneously, the predictive power enhances by increasing similarity with in vivo human conditions. Toxic effects may be detected by performing proliferation, vitality and cell death assays, analysis of protein and hormone expression, immunohistochemistry or testing functionality of signaling pathways, gene expression, transport mechanisms, and so on. When toxic effects appear at any step, the subsequent assays may be cancelled. Such a system may be useful to reduce costs and increase specificity in testing questionable toxicants. Nonetheless, it requires further standardization and end point definitions for better comparability of results from different toxicants and to estimate the respective in vivo translatability and predictive value.
|
|
| 8. |
- Kalkunte, Satyan S., et al.
(författare)
-
Transthyretin Is Dysregulated in Preeclampsia, and Its Native Form Prevents the Onset of Disease in a Preclinical Mouse Model
- 2013
-
Ingår i: American Journal of Pathology. - : ELSEVIER SCIENCE INC, 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA. - 0002-9440 .- 1525-2191. ; 183:5, s. 1425-1436
-
Tidskriftsartikel (refereegranskat)abstract
- Preeclampsia is a major pregnancy complication with potential short- and long-term consequences for both mother and fetus. Understanding its pathogenesis and causative biomarkers is likely to yield insights for prediction and treatment. Herein, we provide evidence that transthyretin, a transporter of thyroxine and retinal, is aggregated in preeclampsia and is present at reduced levels in sera of preeclamptic women, as detected by proteomic screen. We demonstrate that transthyretin aggregates form deposits in preeclampsia placental tissue and cause apoptosis. By using in vitro approaches and a humanized mouse model, we provide evidence for a causal link between dysregulated transthyretin and preeclampsia. Native transthyretin inhibits all preeclampsia-like features in the humanized mouse model, including new-onset proteinuria, increased blood pressure, glomerular endotheliosis, and production of anti-angiogenic factors. Our findings suggest that a focus on transthyretin structure and function is a novel strategy to understand and combat preeclampsia.
|
|
| 9. |
- Svensson-Arvelund, Judit, 1982-, et al.
(författare)
-
The placenta in toxicology. Part II : Systemic and local immune adaptations in pregnancy
- 2014
-
Ingår i: Toxicologic pathology (Print). - : Sage Publications. - 0192-6233 .- 1533-1601. ; 42:2, s. 327-338
-
Tidskriftsartikel (refereegranskat)abstract
- During pregnancy, the maternal immune system is challenged by the semiallogeneic fetus, which must be tolerated without compromising fetal or maternal health. This review updates the systemic and local immune changes taking place during human pregnancy, including some examples in rodents. Systemic changes are induced by contact of maternal blood with placental factors and include enhanced innate immunity with increased activation of granulocytes and nonclassical monocytes. Although a bias toward T helper (Th2) and regulatory T cell (Treg) immunity has been associated with healthy pregnancy, the relationship between different circulating Th cell subsets is not straightforward. Instead, these adaptations appear most evidently at the fetal-maternal interface, where for instance Tregs are enriched and promote fetal tolerance. Also innate immune cells, that is, natural killer cells and macrophages, are enriched, constituting the majority of decidual leukocytes. These cells not only contribute to immune regulation but also aid in establishing the placenta by promoting trophoblast recruitment and angiogenesis. Thus, proper interaction between leukocytes and placental trophoblasts is necessary for normal placentation and immune adaptation. Consequently, spontaneous maladaptation or interference of the immune system with toxic substances may be important contributing factors for the development of pregnancy complications such as preeclampsia, preterm labor, and recurrent miscarriages.
|
|
