scholarly journals TLR4-endothelin axis controls syncytiotrophoblast motility and confers fetal protection in placental malaria

2021 ◽  
Author(s):  
Yash Pandya ◽  
Alexander Marta ◽  
André Barateiro ◽  
Carla Letícia Bandeira ◽  
Jamille Gregório Dombrowski ◽  
...  
Keyword(s):  
Malaria Infection ◽  
Acute Infection ◽  
Primary Cultures ◽  
Placental Malaria ◽  
In Vitro Assays ◽  
Endothelin Receptor ◽  
Fetal Protection ◽  
Endothelin Receptor B ◽  
Adverse Pregnancy

Pregnancy associated malaria is often associated with adverse pregnancy outcomes. Placental circulatory impairments are an intriguing and unsolved component of malaria pathophysiology. Here, we uncovered a TLR4-TRIF-endothelin axis that controls trophoblast motility and is linked to fetal protection during Plasmodium infection. In a cohort of 401 pregnancies from Northern Brazil we found that infection during pregnancy reduced expression of endothelin receptor B in syncytiotrophoblasts while endothelin expression was only affected during acute infection. We further show that quantitative expression of placental endothelin and endothelin receptor B proteins are differentially controlled by maternal and fetal TLR4 alleles. Using murine malaria models, we identified placental autonomous responses to malaria infection mediated by fetally encoded TLR4 that not only controlled placental endothelin gene expression but also correlated with fetal viability protection. In vitro assays showed that control of endothelin expression in fetal syncytiotrophoblasts exposed to Plasmodium -infected erythrocytes was dependent on TLR4 via the TRIF pathway but not MyD88 signaling. Time-lapse microscopy in syncytiotrophoblast primary cultures and cell invasion assays demonstrated that ablation of TLR4 or endothelin receptor blockade abrogate trophoblast collective motility and cell migration responses to infected erythrocytes. These results cohesively substantiate the hypothesis that fetal innate immune sensing, namely the TRL4-TRIF pathway exerts a fetal protective role during malaria infection by mediating syncytiotrophoblast vasoregulatory responses that counteract placental insufficiency.

scholarly journals Factors associated with sub-microscopic placental malaria and its association with adverse pregnancy outcomes among HIV-negative women in Dar es Salaam, Tanzania: a cohort study

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Aneth Vedastus Kalinjuma ◽  
Anne Marie Darling ◽  
Ferdinand M. Mugusi ◽  
Ajibola Ibraheem Abioye ◽  
Fredros O. Okumu ◽  
...  
Keyword(s):  
Birth Weight ◽  
Pregnancy Outcomes ◽  
Malaria Infection ◽  
Placental Malaria ◽  
Adverse Pregnancy Outcomes ◽  
Placental Infection ◽  
Factors Associated ◽  
Adverse Pregnancy ◽  
Prevention Methods ◽  
Dna Pcr

Abstract Background Malaria infection during pregnancy has negative health consequences for both mothers and offspring. Sub-microscopic malaria infection during pregnancy is common in most African countries. We sought to identify factors associated with sub-microscopic placental malaria, and its association with adverse pregnancy outcomes among HIV-negative pregnant women in Dar es Salaam, Tanzania. Methods We recruited a cohort of pregnant women during their first trimester and assessed for the occurrence of placental malaria and pregnancy outcomes. The follow-up was done monthly from recruitment until delivery. Histopathology placental malaria positive results were defined as the presence of malaria pigment or parasitized erythrocytes on the slide (histology-positive (HP)), and the sub-microscopic placental infection was defined as positive Plasmodium falciparum DNA by polymerase chain reaction (DNA PCR) amplification in a negative histopathology test. Adverse pregnancy outcomes investigated included low birth weight (birth weight below 2.5 kg), prematurity (live birth below 37 weeks), and small-for-gestational-age (SGA) (live born with a birth weight below 10th percentile for gestational age and sex). Weighted baseline category logit, log-binomial, and log-Poisson models were used to assess factors associated with placental malaria, and its association with adverse pregnancy outcomes. Results Among 1115 women who had histopathology and DNA PCR performed, 93 (8%) had HP placental infection, and 136 (12%) had the sub-microscopic placental infection. The risk of sub-microscopic placental malaria was greater in women who did not use mosquito prevention methods such as bed nets, fumigation, or mosquito coils (odds ratio (OR) = 1.75; 95% confidence interval (CI): 1.05–2.92; P = 0.03) and in women who were anemic (OR = 1.59; 95% CI: 1.20–2.11; P = 0.001). Women who were underweight had reduced odds of sub-microscopic placental malaria infection (OR = 0.33; 95% CI: 0.17–0.62; P = 0.001). Women who were overweight/obese had 1.48 times higher the odds of HP placental malaria compared to normal weight (OR = 1.48; 95% CI: 1.03–2.11; P = 0.03). HP placental malaria infection was associated with an increased risk of SGA births (RR = 1.30, 95% CI: 0.98–1.72, P = 0.07). In contrast, the sub-microscopic infection was associated with a reduced risk of SGA births (RR = 0.61, 95% CI: 0.43–0.88, P = 0.01). Placental malaria was not associated with low birth weight or prematurity. Conclusion Malaria prevention methods and maternal nutrition status during early pregnancy were important predictors of sub-microscopic placental malaria. More research is needed to understand sub-microscopic placental malaria and the possible mechanisms mediating the association between placental malaria and SGA.

Comparative in-Vitro Evaluation of the Myeloid Toxicity of Pentostatin and the Novel PNP-Inhibitor Forodesine.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3766-3766
Author(s):  
Mario Schubert ◽  
Christian Wallenwein ◽  
Larissa Pietsch ◽  
Dan Ran ◽  
Isabel Taubert ◽  
...  
Keyword(s):  
Primary Cultures ◽  
Flow Cytometric Analysis ◽  
Chemotherapeutic Agents ◽  
Dose Effect ◽  
In Vitro Assays ◽  
In Vitro Toxicity ◽  
The Novel ◽  
Xtt Assay ◽  
Cd34 Cells

Abstract Abstract 3766 Poster Board III-702 Inhibitors of the purine metabolism show promising results in the treatment of lymphatic malignancies due to their suppressive effects on lymphogenesis. Their first representative, Pentostatin (Pento), an inhibitor of the deoxyadenosine deaminase, has been in clinical use for several decades. However, early clinical trials with higher dose ranges of the drug reported unforseen severe myelotoxic effects. Recently, Forodesine (Foro), a novel inhibitor of the nucleoside phosphorylase (PNP) has been introduced and is currently deployed in clinical phase I/II trials for the treatment of acute lymphatic leukemia (ALL). In order to systematically evaluate the myelotoxic effects of Pento and Foro, we have now examined their influence on the proliferation and differentiation of primitive and lineage committed hematopoietic progenitor cells (HPCs). In vitro dose/effect-curves for Foro, Pento, and Cytarabine (AraC) were generated for the leukemic cell line jurkat by 48 hours of co-incubation with the compounds. Adequate cytotoxic effects, measured in the XTT assay and by flow cytometric analysis, were observed in clinically relevant dose ranges. For the following studies, an equivalent IC60 dose of each chemotherapeutic agent was selected and CD34+ HPCs from either bone marrow, mobilized peripheral blood, or umbilical cord blood were incubated with the compounds for 48 hours. Subsequently, the rate of vital cells was determined by flow cytometry after stainig with Annexin-V and Propidium Iodide. Compared to the untreated control, the lowest amount of vital CD34+ cells was found in AraC-treated samples (30%); Foro and Pento yielded more vital cells (66% vs 61%). The combination of Foro and Pento unexpectedly had the least toxic effect on CD34+ cells (72%; n=5; p<0.05). Cells from those primary cultures were harvested and short- and long term in vitro assays for colony forming units were performed to evaluate the compounds' toxicity on primitive and lineage committed HPCs. The frequency of primitive myeloic progenitors (LTC-IC) was 2.3% in the untreated samples and diminished after treatment with AraC (1.2%) and Pento (1.9%) but surprisingly significantly increased after Foro-treatment (2.7%); the combination of Foro and Pento resulted in a LTC-IC frequency of 2.3% (p<0.01; n=5) suggesting that Foro may have attenuated the myelotoxicity of Pento. Similar effects of Foro were also observed in the short term colony forming assays where Foro seemed to have a protective effect on multipotent GEMM-progenitors: colony count increased 1.3-fold in comparison to the control; AraC yielded only 0.1-fold, Pento 0.8-fold and the combination of Pento and Foro reached 0.9-fold of the control (p<0.05; n=15). In summary, the novel PNP-inhibitor Forodesine has not only proven to have a low in vitro toxicity on lineage committed HPCs but, surprisingly, the frequency of primitive myeloic progenitors (LTC-IC) increased; clinical studies should therefore be performed to evaluate whether Forodesine, while adding to the therapeutic efficiency, may attenuate adverse effects in combination with other chemotherapeutic agents, such as Pentostatin. Disclosures: Schubert: Mundipharma Int. LTD: Research Funding.

scholarly journals Comediation of Erythrocyte Haemolysis by Erythrocyte-Derived Microparticles and Complement during Malaria Infection

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Ransford Kyeremeh ◽  
Samuel Antwi-Baffour ◽  
Max Annani-Akollor ◽  
Jonathan Kofi Adjei ◽  
Otchere Addai-Mensah ◽  
...  
Keyword(s):  
Malaria Infection ◽  
Surface Protein ◽  
Surface Proteins ◽  
Sub Saharan Africa ◽  
In Vitro Assays ◽  
Intracellular Location ◽  
Fixed Volume ◽  
Global Threat ◽  
Erythrocyte Haemolysis

Background. Due to the sustained morbidity and mortality that malaria-associated anaemia imposes on patients, malaria is still a global threat, most especially, to residents in sub-Saharan Africa. Merozoite invasion and destruction of erythrocytes, a target for this study, have been necessary due to its unique nature and also since the erythrocytes suffer the most brunt of malarial infection leading to anaemia. The issue of malaria anaemia has to do with why uninfected RBCs get destroyed and even more so than infected ones. Studies have proposed that cytophilic anti-RSP2 (ring surface protein 2—merozoite rhoptry protein 2) antibodies present in sera enhance phagocytosis of RSP2-tagged RBCs by macrophages either directly or via complement, while others have proposed transfer of RSP2 to both infected and uninfected RBCs which may render them susceptible to phagocytosis. What is missing is the agent involved in the transfer of these parasite-induced surface proteins onto the uninfected RBCs, i.e., the mediator molecules. Considering the intracellular location of the parasite in the parasitophorous vacuolar membrane and the absence of a transport mechanism such as the Golgi apparatus within the mature RBC, since the latter has no nucleus, we propose that erythrocyte-derived microparticles (EMPs) may be the possible mediators. Aim. This study aimed at examining the immunological interactions between EMPs released during malarial infections and host erythrocytes that may lead to their lysis possibly through complement mediation. Methods. This was an experimental study during which malarial EMPs were isolated by differential centrifugation of malaria-positive plasma. This was followed by cell-based in vitro assays where malaria-positive EMPs were added to uninfected blood group “O” negative erythrocytes in the presence of complement and haemolysis checked for. Results and Conclusion. At a fixed volume of 50 μL complement, there were statistically significant (p<0.01) increases in mean percentage haemolysis as the volume of EMPs increased. Similarly, at a fixed volume of 50 μL EMPs, there were statistically significant (p<0.01) increases in mean percentage haemolysis with increasing volumes of complement. This was an indication that both complement and EMPs contribute significantly to uninfected erythrocyte haemolysis during malaria infection.

scholarly journals Ribavirin Induces Error-Prone Replication of GB Virus B in Primary Tamarin Hepatocytes

2001 ◽  
Vol 75 (17) ◽  
pp. 8074-8081 ◽  
Author(s):  
Robert E. Lanford ◽  
Deborah Chavez ◽  
Bernadette Guerra ◽  
J. Y. N. Lau ◽  
Zhi Hong ◽  
...  
Keyword(s):  
Acute Infection ◽  
Primary Cultures ◽  
Antiviral Effect ◽  
Hcv Infection ◽  
Viral Rna ◽  
Human Interferon ◽  
Antiviral Compounds ◽  
Concomitant Reduction

ABSTRACT GB virus B (GBV-B) is the closest relative of hepatitis C virus (HCV) and is an attractive surrogate model for HCV antiviral studies. GBV-B induces an acute, resolving hepatitis in tamarins. Utilizing primary cultures of tamarin hepatocytes, we have previously developed a tissue culture system that exhibits high levels of GBV-B replication. In this report, we have extended the utility of this system for testing antiviral compounds. Treatment with human interferon provided only a marginal antiviral effect, while poly(I-C) yielded >3 and 4 log units of reduction of cell-associated and secreted viral RNA, respectively. Interestingly, treatment of GBV-B-infected hepatocytes with ribavirin resulted in an approximately 4-log decrease in viral RNA levels. Guanosine blocked the antiviral effect of ribavirin, suggesting that inhibition of IMP dehydrogenase (IMPDH) and reduction of intracellular GTP levels were essential for the antiviral effect. However, mycophenolic acid, another IMPDH inhibitor, had no antiviral effect. Virions harvested from ribavirin-treated cultures exhibited a dramatically reduced specific infectivity. These data suggest that incorporation of ribavirin triphosphate induces error-prone replication with concomitant reduction in infectivity and that reduction of GTP pools may be required for incorporation of ribavirin triphosphate. In contrast to the in vitro studies, no significant reduction in viremia was observed in vivo following treatment of tamarins with ribavirin during acute infection with GBV-B. These findings are consistent with the observation that ribavirin monotherapy for HCV infection decreases liver disease without a significant reduction in viremia. Our data suggest that nucleoside analogues that induce error-prone replication could be an attractive approach for the treatment of HCV infection if administered at sufficient levels to result in efficient incorporation by the viral polymerase.

A in Vivo Assay for Standardizing Heparin Preparations

1979 ◽  
Vol 41 (03) ◽  
pp. 576-582
Author(s):  
A R Pomeroy
Keyword(s):  
In Vitro Assays ◽  
British Pharmacopoeia ◽  
In Vitro Method ◽  
Standard Preparation ◽  
Reliable Estimation ◽  
Assay Procedure ◽  
Accuracy And Precision ◽  
Heparin Preparation

SummaryThe limitations of currently used in vitro assays of heparin have demonstrated the need for an in vivo method suitable for routine use.The in vivo method which is described in this paper uses, for each heparin preparation, four groups of five mice which are injected intravenously with heparin according to a “2 and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours to test five heparin preparations against a standard preparation of heparin. Levels of accuracy and precision acceptable for the requirements of the British Pharmacopoeia are obtained by combining the results of 3 to 4 assays of a heparin preparation.The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia gives a reliable estimation of the in vivo activity of heparin.

Potentially Thrombogenic Materials in Factor IX Concentrates

1975 ◽  
Vol 33 (03) ◽  
pp. 617-631 ◽  
Author(s):  
H. S Kingdon ◽  
R. L Lundblad ◽  
J. J Veltkamp ◽  
D. L Aronson
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Factor Ix ◽  
In Vitro Assays ◽  
Substantial Agreement ◽  
Coefficient Of Correlation

SummaryFactor IX concentrates manufactured from human plasma and intended for therapeutic infusion in man have been suspected for some time of being potentially thrombogenic. In the current studies, assays were carried out in vitro and in vivo for potentially thrombogenic materials. It was possible to rank the various materials tested according to the amount of thrombogenic material detected. For concentrates not containing heparin, there was substantial agreement between the in vivo and in vitro assays, with a coefficient of correlation of 0.77. There was no correlation between the assays for thrombogenicity and the antithrombin III content. We conclude that many presently available concentrates of Factor IX contain substantial amounts of potentially thrombogenic enzymes, and that this fact must be considered in arriving at the decision whether or not to use them therapeutically.

Pulsatile GnRH secretion from primary cultures of sheep olfactory placode explants

Reproduction ◽  
2000 ◽  
pp. 391-396 ◽  
Author(s):  
AH Duittoz ◽  
M Batailler
Keyword(s):  
Culture Medium ◽  
Primary Cultures ◽  
Pulsatile Secretion ◽  
Olfactory Placode ◽  
Gnrh Secretion ◽  
Individual Culture ◽  
Pulsatile Gnrh

The aim of this study was to investigate the development of pulsatile GnRH secretion by GnRH neurones in primary cultures of olfactory placodes from ovine embryos. Culture medium was collected every 10 min for 8 h to detect pulsatile secretion. In the first experiment, pulsatile secretion was studied in two different sets of cultures after 17 and 24 days in vitro. In the second experiment, a set of cultures was tested after 10, 17 and 24 days in vitro to investigate the development of pulsatile GnRH secretion in each individual culture. This study demonstrated that (i) primary cultures of GnRH neurones from olfactory explants secreted GnRH in a pulsatile manner and that the frequency and mean interpulse duration were similar to those reported in castrated ewes, and (ii) pulsatile secretion was not present at the beginning of the culture but was observed between 17 and 24 days in vitro, indicating the maturation of individual neurones and the development of their synchronization.

In-silico Studies of Isolated Phytoalkaloid Against Lipoxygenase: Study Based on Possible Correlation

2018 ◽  
Vol 21 (3) ◽  
pp. 215-221
Author(s):  
Haroon Khan ◽  
Muhammad Zafar ◽  
Helena Den-Haan ◽  
Horacio Perez-Sanchez ◽  
Mohammad Amjad Kamal
Keyword(s):  
In Silico ◽  
Docking Studies ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Chronic Obstructive ◽  
Lipoxygenase Inhibitors ◽  
Lipoxygenase Inhibition ◽  
In Silico Studies

Aim and Objective: Lipoxygenase (LOX) enzymes play an important role in the pathophysiology of several inflammatory and allergic diseases including bronchial asthma, allergic rhinitis, atopic dermatitis, allergic conjunctivitis, rheumatoid arthritis and chronic obstructive pulmonary disease. Inhibitors of the LOX are believed to be an ideal approach in the treatment of diseases caused by its over-expression. In this regard, several synthetic and natural agents are under investigation worldwide. Alkaloids are the most thoroughly investigated class of natural compounds with outstanding past in clinically useful drugs. In this article, we have discussed various alkaloids of plant origin that have already shown lipoxygenase inhibition in-vitro with possible correlation in in silico studies. Materials and Methods: Molecular docking studies were performed using MOE (Molecular Operating Environment) software. Among the ten reported LOX alkaloids inhibitors, derived from plant, compounds 4, 2, 3 and 1 showed excellent docking scores and receptor sensitivity. Result and Conclusion: These compounds already exhibited in vitro lipoxygenase inhibition and the MOE results strongly correlated with the experimental results. On the basis of these in vitro assays and computer aided results, we suggest that these compounds need further detail in vivo studies and clinical trial for the discovery of new more effective and safe lipoxygenase inhibitors. In conclusion, these results might be useful in the design of new and potential lipoxygenase (LOX) inhibitors.

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