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Nanomedicine holds immense potential for therapeutic manipulation of phagocytic immune cells. However, in vitro studies often fail to accurately translate to the complex in vivo environment. To address this gap, we employed an ex vivo human whole-blood assay to evaluate liposome interactions with immune cells. We systematically varied liposome size, PEG-surface densities and sphingomyelin and ganglioside content. We observed differential uptake patterns of the assessed liposomes by neutrophils and monocytes, emphasizing the importance of liposome design. Interestingly, our results aligned closely with published in vivo observations in mice and patients. Moreover, liposome exposure induced changes in cytokine release and cellular responses, highlighting the potential modulation of immune system. Our study highlights the utility of human whole-blood models in assessing nanoparticle-immune cell interactions and provides insights into liposome design for modulating immune responses., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Alginate microspheres are presently under evaluation for future cell-based therapy. Their ability to induce harmful host reactions needs to be identified for developing the most suitable devices and efficient prevention strategies. We used a lepirudin based human whole blood model to investigate the coagulation potentials of alginate-based microspheres: alginate microbeads (Ca/Ba Beads), alginate poly-l-lysine microcapsules (APA and AP microcapsules) and sodium alginate-sodium cellulose sulfate-poly(methylene-co-cyanoguanidine) microcapsules (PMCG microcapsules). Coagulation activation measured by prothrombin fragments 1+2 (PTF1.2) was rapidly and markedly induced by the PMCG microcapsules, delayed and lower induced by the APA and AP microcapsules, and not induced by the Ca/Ba Beads. Monocytes tissue factor (TF) expression was similarly activated by the microcapsules, whereas not by the Ca/Ba Beads. PMCG microcapsules-induced PTF1.2 was abolished by FXII inhibition (corn trypsin inhibitor), thus pointing to activation through the contact pathway. PTF1.2 induced by the AP and APA microcapsules was inhibited by anti-TF antibody, pointing to a TF driven coagulation. The TF induced coagulation was inhibited by the complement inhibitors compstatin (C3 inhibition) and eculizumab (C5 inhibition), revealing a complement-coagulation cross-talk. This is the first study on the coagulation potentials of alginate microspheres, and identifies differences in activation potential, pathways and possible intervention points., Statement of Significance: Alginate microcapsules are prospective candidate materials for cell encapsulation therapy. The material surface must be free of host cell adhesion to ensure free diffusion of nutrition and oxygen to the encapsulated cells. Coagulation activation is one gateway to cellular overgrowth through deposition of fibrin. Herein we used a physiologically relevant whole blood model to investigate the coagulation potential of alginate microcapsules and microbeads. The coagulation potentials and the pathways of activation were depending on the surface properties of the materials. Activation of the complement system could also be involved, thus emphasizing a complement-coagulation cross-talk. Our findings points to complement and coagulation inhibition as intervention point for preventing host reactions, and enhance functional cell-encapsulation devices., (Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Introduction: The first trimester of pregnancy is characterised by a mild pro-inflammatory environment, however excessive inflammation threatens placental development and function. Toll-like receptors (TLRs) are crucial in initiating inflammation. TLR1, TLR2, TLR4, TLR5, TLR6 and TLR10 are expressed on the cell surface, and respond to microbial infection and cell damage and stress signals. Recent findings of TLRs in trophoblasts indicate a role in inflammation during pregnancy, but further studies are warranted., Objectives: To investigate gene expression and function of cell surface TLRs in first trimester trophoblasts, to extend knowledge on the role of trophoblast TLRs during placental development., Methods: Primary trophoblasts were isolated from first trimester placentas (n=6) by enzyme degradation and density gradient centrifugation. Gene expression of TLR1, TLR2, TLR4, TLR5, TLR6 and TLR10 was quantified by RT-qPCR in primary first trimester trophoblasts and the trophoblast cell line BeWo. Trophoblasts were stimulated with cell surface TLR ligands and pro-inflammatory cytokine release was analysed by multiplex immunoassay., Results: Primary first trimester trophoblasts expressed all cell surface TLR mRNAs, and activation of TLR2/1, TLR4 and TLR5 induced IL-6 and/or IL-8., Conclusion: The broad expression of functional cell surface TLRs in primary first trimester trophoblasts suggests a central role for trophoblasts in placental inflammation and immune activation., (Copyright © 2013. Published by Elsevier B.V.)

Introduction: A mild systemic inflammation may be beneficial to normal pregnancy, however exaggerated inflammation may contribute to pregnancy complications. Infections and cell stress or damage may evoke placental inflammation by activation of Toll-like receptors (TLRs). TLR3, TLR7, TLR8 and TLR9 are located intracellulary on endosomes and are activated by nucleic acids from microbes and damaged cells. Trophoblasts play a crucial role during placentation, and the role of TLRs in first trimester trophoblasts needs to be determined., Objectives: To characterize endosomal TLR gene expression and activation in first trimester trophoblasts, to extend knowledge of endosomal TLR involvement in placental inflammation., Methods: Primary trophoblasts were isolated from six first trimester placentas by enzyme degradation and gradient centrifugation. Gene expression of TLR3, TLR7, TLR8 and TLR9 in primary first trimester trophoblasts and the trophoblast cell line BeWo was quantified by RT-qPCR. The trophoblasts were stimulated with ligands for endosomal TLRs, and release of pro-inflammatory cytokines was analyzed by multiplex., Results: Primary first trimester trophoblasts showed gene expression of all endosomal TLRs, and endosomal TLR activation gave increased production of the pro-inflammatory cytokines IL-6, IL-8, and IP-10., Conclusion: Primary first trimester trophoblasts express functional endosomal TLRs, indicating TLR-mediated trophoblast involvement in early placental inflammation., (Copyright © 2013. Published by Elsevier B.V.)

Alginate microbeads and microcapsules are presently under evaluation for future cell-based therapy. Defining their inflammatory properties with regard to humans is therefore essential. A lepirudine-based human whole blood model was used as an inflammation predictor by measuring complement and leukocyte stimulation. Alginate microbeads were complement-compatible since they did not activate complement as measured by the soluble terminal complement complex (sTCC), Bb or the anaphylatoxins C3a and C5a. In addition, alginate microbeads were free of surface adherent leukocytes. In contrast, microcapsules containing poly-L-lysine (PLL) induced elevated levels of sTCC, Bb, C3a and C5a, surface active C3 convertase and leukocyte adhesion. The soluble PLL induced elevated levels of sTCC and up-regulated leukocyte CD11b expression. PMCG microcapsules containing poly(methylene-co-guanidine) complexed with sodium alginate and cellulose sulfate triggered a fast sTCC response and C3 deposition. The PMCG microcapsules were still less activating than PLL-containing microcapsules as a function of time. The amounts of anaphylatoxins C3a and C5a were diminished by the PMCG microcapsules, whereas leukocyte adherence demonstrated surface activating properties. We propose the whole blood model as an important tool for measuring bioincompatibility of microcapsules and microbeads for future applications as well as determining the mechanisms leading to inflammatory reactions., (Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)