Prognostic significance of circulating tumor cells and tumor related transcripts in small cell lung cancer: A step further to clinical implementation

Small-cell lung cancer (SCLC) is a fatal disease with limited treatment options. Circulating tumor cells (CTCs) in liquid biopsy samples may serve as predictive and prognostic biomarkers; but the analysis of CTCs is still challenging. By using microfluidic or density gradient CTC enrichment in combination with immunofluorescent (IF) staining or qPCR of CTC-related transcripts, we achieved a 60.8% to 88.0% positivity in SCLC blood samples. Epithelial and neuroendocrine transcripts including the druggable target DLL3 were associated with shorter overall survival (OS), indicating the clinical value of these markers in terms of differential diagnosis and treatment decisions. High CTC counts and the presence of CTC duplets detected by IF staining were prognostic for OS, and thus may serve as indicators of disease progression or therapy failure. In patient samples with high CTC load detected by IF staining, a concordance of the transcripts positivity in circulating free plasma RNA and CTCs was observed. Our data emphasize the role of CTCs and CTC-related transcripts and underline the clinical value of liquid biopsy analysis in SCLC.

Single molecule studies of dynamic platelet interactions with endothelial cells

A biotechnological platform consisting of two-color 3D super-resolution readout and a microfluidic system was developed to investigate platelet interaction with a layer of perfused endothelial cells under flow conditions. Platelet activation has been confirmed via CD62P clustering on the membrane and mitochondrial morphology of ECs at the single cell level were examined using 3D two-color single-molecule localization microscopy and classified applying machine learning. To compare binding of activated platelets to intact or stressed ECs, a femtosecond laser was used to induced damage to single ECs within the perfused endothelial layer. We observed that activated platelets bound to the perfused ECs layer preferentially in the proximity to single stressed ECs. Platelets activated under flow were ∼6 times larger compared to activated ones under static conditions. The CD62P expression indicated more CD62P proteins on membrane of dynamically activated platelets, with a tendency to higher densities at the platelet/EC interface. Platelets activated under static conditions showed a less pronounced CD62P top/bottom asymmetry. The clustering of CD62P in the platelet membrane differs depending on the activation conditions. Our results confirm that nanoscopic analysis using two-color 3D super-resolution technology can be used to assess platelet interaction with a stressed endothelium under dynamic conditions.

Impact of production methods and storage conditions on extracellular vesicles in packed red blood cells and platelet concentrates

The use of blood and blood products can be life-saving, but there are also certain risks associated with their administration and use. Packed red blood cells (pRBCs) and platelet concentrates are the most commonly used blood products in transfusion medicine to treat anemia or acute and chronic bleeding disorders, respectively. During the production and storage of blood products, red blood cells and platelets release extracellular vesicles (EVs) as a result of the storage lesion, which may affect product quality. EVs are subcellular structures enclosed by a lipid bilayer and originate from the endosomal system or from the plasma membrane. They play a pivotal role in intercellular communication and are emerging as important regulators of inflammation and coagulation. Their cargo and their functional characteristics depend on the cell type from which they originate, as well as on their microenvironment, influencing their capacity to promote coagulation and inflammatory responses. Hence, the potential involvement of EVs in transfusion-related adverse events is increasingly recognized and studied. Here, we review the knowledge regarding the effect of production and storage conditions of pRBCs and platelet concentrates on the release of EVs. In this context, the mode of processing and anticoagulation, the influence of additive solutions and leukoreduction, as well as the storage duration will be addressed, and we discuss potential implications of EVs for the clinical outcome of transfusion.

Association of Four Interleukin-8 Polymorphisms (-251 A>T, +781 C>T, +1633 C>T, +2767 A>T) with Ovarian Cancer Risk: Focus on Menopausal Status and Endometriosis-Related Subtypes

Interleukin-8 (IL-8) is involved in the regulation of inflammatory processes and carcinogenesis. Single-nucleotide polymorphisms (SNPs) within the IL-8 gene have been shown to alter the risks of lung, gastric, or hepatocellular carcinomas. To date, only one study examined the role of IL-8 SNPs in ovarian cancer (OC), suggesting an association between two IL-8 SNPs and OC risk. In this study, we investigated four common IL-8 SNPs, rs4073 (-251 A>T), rs2227306 (+781 C>T), rs2227543 (+1633 C>T), and rs1126647 (+2767 A>T), using the restriction fragment length polymorphism (PCR-RFLP) technique. Our study included a cohort of 413 women of Central European descent, consisting of 200 OC patients and 213 healthy controls. The most common (73.5%) histological type was high-grade serous OC (HGSOC), whereas 28/200 (14%) patients had endometriosis-related (clear cell or endometrioid) OC subtypes (EROC). In postmenopausal women, three of the four investigated SNPs, rs4073 (-251 A>T), rs2227306 (+781 C>T), and rs2227543 (+1633 C>T), were associated with OC risk. Furthermore, we are the first to report a significant relationship between the T allele or TT genotype of SNP rs1126647 (+2767 A>T) and the EROC subtype (p = 0.02 in the co-dominant model). The TT homozygotes were found more than twice as often in EROC compared to other OC subtypes (39% vs. 19%, p = 0.015). None of the examined SNPs appeared to influence OC risk in premenopausal women, nor were they associated with the aggressive HGSOC subtype or the stage of disease at the initial diagnosis.

Functionally impaired antibody response to BNT162b2 booster vaccination in CVID IgG responders

BACKGROUND

Although previous studies described the production of IgG antibodies in a subgroup of patients with common variable immunodeficiency (CVID) following messenger RNA vaccinations with BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (CVID responders), the functionality of these antibodies in terms of avidity as measured by the dissociation rate constant (k_dis) and the antibody response to booster immunization has not been studied.

OBJECTIVE

We sought to analyze in CVID responders and healthy individuals, the avidity of anti-SARS-CoV-2 serum antibodies and their neutralization capacity as measured by surrogate virus-neutralizing antibodies in addition to IgG-, IgM-, and IgA-antibody levels and the response of circulating (peripheral blood) follicular T-helper cells after a third vaccination with BNT162b2 SARS-CoV-2 messenger RNA vaccine.

METHODS

Binding IgG, IgA, and IgM serum levels were analyzed by ELISA in patients with CVID responding to the primary vaccination (CVID responders, n = 10) and healthy controls (n = 41). The binding avidity of anti-spike antibodies was investigated using biolayer interferometry in combination with biotin-labeled receptor-binding-domain of SARS-CoV-2 spike protein and streptavidin-labeled sensors. Antigen-specific recall T-cell responses were assessed by measuring activation-induced markers by flow cytometry.

RESULTS

After the third vaccination with BNT162b2, IgG-, IgM-, and IgA-antibody levels, surrogate virus-neutralizing antibody levels, and antibody avidity were lower in CVID responders than in healthy controls. In contrast, anti-SARS-CoV-2 spike protein avidity was comparable in CVID responders and healthy individuals following primary vaccination. Follicular T-helper cell response to booster vaccination in CVID responders was significantly reduced when compared with that in healthy individuals.

CONCLUSIONS

Impaired affinity maturation during booster response provides new insight into CVID pathophysiology.

Interleukin-4 receptor alpha signaling regulates monocyte homeostasis

Interleukin‐4 (IL‐4) and its receptors (IL‐4R) promote the proliferation and polarization of macrophages. However, it is unknown if IL‐4R also influences monocyte homeostasis and if steady state IL‐4 levels are sufficient to affect monocytes. Employing full IL‐4 receptor alpha knockout mice (IL‐4Rα^−/−) and mice with a myeloid‐specific deletion of IL‐4Rα (IL‐4Rα^f/f LysM^cre), we show that IL‐4 acts as a homeostatic factor regulating circulating monocyte numbers. In the absence of IL‐4Rα, murine monocytes in blood were reduced by 50% without altering monocytopoiesis in the bone marrow. This reduction was accompanied by a decrease in monocyte‐derived inflammatory cytokines in the plasma. RNA sequencing analysis and immunohistochemical staining of splenic monocytes revealed changes in mRNA and protein levels of anti‐apoptotic factors including BIRC6 in IL‐4Rα^−/− knockout animals. Furthermore, assessment of monocyte lifespan in vivo measuring BrdU⁺ cells revealed that the lifespan of circulating monocytes was reduced by 55% in IL‐4Rα^−/− mice, whereas subcutaneously applied IL‐4 prolonged it by 75%. Treatment of human monocytes with IL‐4 reduced the amount of dying monocytes in vitro. Furthermore, IL‐4 stimulation reduced the phosphorylation of proteins involved in the apoptosis pathway, including the phosphorylation of the NFκBp65 protein. In a cohort of human patients, serum IL‐4 levels were significantly associated with monocyte counts. In a sterile peritonitis model, reduced monocyte counts resulted in an attenuated recruitment of monocytes upon inflammatory stimulation in IL‐4Rα^f/f LysM^cre mice without changes in overall migratory function. Thus, we identified a homeostatic role of IL‐4Rα in regulating the lifespan of monocytes in vivo.

Antigen-Specific CD4+ T-Cell Activation in Primary Antibody Deficiency After BNT162b2 mRNA COVID-19 Vaccination

Previous studies on immune responses following COVID-19 vaccination in patients with common variable immunodeficiency (CVID) were inconclusive with respect to the ability of the patients to produce vaccine-specific IgG antibodies, while patients with milder forms of primary antibody deficiency such as immunoglobulin isotype deficiency or selective antibody deficiency have not been studied at all. In this study we examined antigen-specific activation of CXCR5-positive and CXCR5-negative CD4⁺ memory cells and also isotype-specific and functional antibody responses in patients with CVID as compared to other milder forms of primary antibody deficiency and healthy controls six weeks after the second dose of BNT162b2 vaccine against SARS-CoV-2. Expression of the activation markers CD25 and CD134 was examined by multi-color flow cytometry on CD4⁺ T cell subsets stimulated with SARS-CoV-2 spike peptides, while in parallel IgG and IgA antibodies and surrogate virus neutralization antibodies against SARS-CoV-2 spike protein were measured by ELISA. The results show that in CVID and patients with other milder forms of antibody deficiency normal IgG responses (titers of spike protein-specific IgG three times the detection limit or more) were associated with intact vaccine-specific activation of CXCR5-negative CD4⁺ memory T cells, despite defective activation of circulating T follicular helper cells. In contrast, CVID IgG nonresponders showed defective vaccine-specific and superantigen-induced activation of both CD4⁺T cell subsets. In conclusion, impaired TCR-mediated activation of CXCR5-negative CD4⁺ memory T cells following stimulation with vaccine antigen or superantigen identifies patients with primary antibody deficiency and impaired IgG responses after BNT162b2 vaccination.

Quantitative and Functional Assessment of the Influence of Routinely Used Cryopreservation Media on Mononuclear Leukocytes for Medical Research

Quantitative and functional analysis of mononuclear leukocyte populations is an invaluable tool to understand the role of the immune system in the pathogenesis of a disease. Cryopreservation of mononuclear cells (MNCs) is routinely used to guarantee similar experimental conditions. Immune cells react differently to cryopreservation, and populations and functions of immune cells change during the process of freeze–thawing. To allow for a setup that preserves cell number and function optimally, we tested four different cryopreservation media. MNCs from 15 human individuals were analyzed. Before freezing and after thawing, the distribution of leukocytes was quantified by flow cytometry. Cultured cells were stimulated using lipopolysaccharide, and their immune response was quantified by flow cytometry, quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay (ELISA). Ultimately, the performance of the cryopreservation media was ranked. Cell recovery and viability were different between the media. Cryopreservation led to changes in the relative number of monocytes, T cells, B cells, and their subsets. The inflammatory response of MNCs was altered by cryopreservation, enhancing the basal production of inflammatory cytokines. Different cryopreservation media induce biases, which needs to be considered when designing a study relying on cryopreservation. Here, we provide an overview of four different cryopreservation media for choosing the optimal medium for a specific task.

Heparin-Functionalized Adsorbents Eliminate Central Effectors of Immunothrombosis, including Platelet Factor 4, High-Mobility Group Box 1 Protein and Histones

Inflammation and thrombosis are closely intertwined in numerous disorders, including ischemic events and sepsis, as well as coronavirus disease 2019 (COVID-19). Thrombotic complications are markers of disease severity in both sepsis and COVID-19 and are associated with multiorgan failure and increased mortality. Immunothrombosis is driven by the complement/tissue factor/neutrophil axis, as well as by activated platelets, which can trigger the release of neutrophil extracellular traps (NETs) and release further effectors of immunothrombosis, including platelet factor 4 (PF4/CXCL4) and high-mobility box 1 protein (HMGB1). Many of the central effectors of deregulated immunothrombosis, including activated platelets and platelet-derived extracellular vesicles (pEVs) expressing PF4, soluble PF4, HMGB1, histones, as well as histone-decorated NETs, are positively charged and thus bind to heparin. Here, we provide evidence that adsorbents functionalized with endpoint-attached heparin efficiently deplete activated platelets, pEVs, PF4, HMGB1 and histones/nucleosomes. We propose that this elimination of central effectors of immunothrombosis, rather than direct binding of pathogens, could be of clinical relevance for mitigating thrombotic complications in sepsis or COVID-19 using heparin-functionalized adsorbents.

A 3-Dimensional In Vitro Model of Zonally Organized Extracellular Matrix

OBJECTIVE

Functional cartilage repair requires the new formation of organized hyaline cartilaginous matrix to avoid the generation of fibrous repair tissue. The potential of mesenchymal progenitors was used to assemble a 3-dimensional structure in vitro, reflecting the zonation of collagen matrix in hyaline articular cartilage.

DESIGN

The 3-dimensional architecture of collagen alignment in pellet cultures of chondroprogenitors (CPs) was assessed with Picrosirius red staining analyzed under polarized light. In parallel assays, the trilineage capability was confirmed by calcium deposition during osteogenesis by alizarin S staining and alkaline phosphatase staining. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), mRNA levels of ALP, RUNX2, and BGLAP were assessed after 21 days of osteoinduction. Lipid droplets were stained with oil red O and adipogenic differentiation was confirmed by RT-qPCR analysis of PPARG and LPL gene expression.

RESULTS

Under conditions promoting the chondrogenic signature in self-assembling constructs, CPs formed an aligned extracellular matrix, positive for glycosaminoglycans and collagen type II, showing developing zonation of birefringent collagen fibers along the cross section of pellets, which reflect the distribution of collagen fibers in hyaline cartilage. Induced osteogenic and adipogenic differentiation confirmed the trilineage potential of CPs.

CONCLUSION

This model promotes the differentiation and self-organization of postnatal chondroprogenitors, resulting in the formation of zonally organized engineered hyaline cartilage comparable to the 3 zones of native cartilage.

Dependence of mitochondrial function on the filamentous actin cytoskeleton in cultured mesenchymal stem cells treated with cytochalasin B

Owing to their self-renewal and multi-lineage differentiation capability, mesenchymal stem cells (MSCs) hold enormous potential in regenerative medicine. A prerequisite for a successful MSC therapy is the rigorous investigation of their function after in vitro cultivation. Damages introduced to mitochondria during cultivation adversely affect MSCs function and can determine their fate. While it has been shown that microtubules and vimentin intermediate filaments are important for mitochondrial dynamics and active mitochondrial transport within the cytoplasm of MSCs, the role of filamentous actin in this process has not been fully understood yet. To gain a deeper understanding of the interdependence between mitochondrial function and the cytoskeleton, we applied cytochalasin B to disturb the filamentous actin-based cytoskeleton of MSCs. In this study we combined conventional functional assays with a state-of-the-art oxygen sensor-integrated microfluidic device to investigate mitochondrial function. We demonstrated that cytochalasin B treatment at a dose of 16 μM led to a decrease in cell viability with high mitochondrial membrane potential, increased oxygen consumption rate, disturbed fusion and fission balance, nuclear extrusion and perinuclear accumulation of mitochondria. Treatment of MSCs for 48 h ultimately led to nuclear fragmentation, and activation of the intrinsic pathway of apoptotic cell death. Importantly, we could show that mitochondrial function of MSCs can efficiently recover from the damage to the filamentous actin-based cytoskeleton over a period of 24 h. As a result of our study, a causative connection between the filamentous actin-based cytoskeleton and mitochondrial dynamics was demonstrated.

Signs of sympathetic and endothelial cell activation in the skin of patients with restless legs syndrome

OBJECTIVES

To evaluate skin biopsies of patients with early- and late onset restless legs syndrome (RLS) for concomitant small fiber neuropathy (SFN) and to determine cutaneous sympathetic innervation and microvascularization in comparison to healthy individuals.

METHODS

Density of intraepidermal nerve fibers (IENFD), adrenergic nerve fibers and dermal capillaries was analyzed by immunofluorescence for PGP9.5, tyrosine hydroxylase and endothelial markers CD31 and CD105 in skin biopsies of 11 individuals with RLS and 8 age- and sex-matched controls.

RESULTS

IENFD did not differ between RLS and controls, but two RLS patients with comorbid impaired glucose metabolism fulfilled morphometric criteria of SFN according to published normative values. In contrast, dermal nerve bundles of RLS patients showed an increased density of tyrosine hydroxylase⁺ adrenergic nerve fibers (p < 0.005). Moreover, an increased ratio between immature CD105⁺ and mature CD31⁺ endothelial cells within dermal capillaries was observed in RLS (p < 0.02).

CONCLUSIONS

SFN, as a potential contributing factor for RLS, should be considered in patients with predisposing comorbidities presenting with burning or shooting pain, dysesthesias and impaired sensory and temperature perception. Evidence of an increased adrenergic innervation of the skin in RLS patients is in accordance with sympathetic hyperactivity while signs of endothelial cell activation may reflect an adaptive response to tissue hypoxia.

Pharmacological inhibition of fatty acid oxidation reduces atherosclerosis progression by suppression of macrophage NLRP3 inflammasome activation

BACKGROUND

Inflammation is a key process during atherosclerotic lesion development and propagation. Recent evidence showed clearly that especially the inhibition of interleukin (IL)-1β reduced atherosclerotic adverse events in human patients. Fatty acid oxidation (FAO) was previously demonstrated to interact with the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) pathway which is required for mature IL-1β secretion. To understand possible anti-inflammatory properties of FAO inhibition, we tested the effect of pharmacological FAO inhibition using the inhibitor for long-chain 3-ketoacyl coenzyme A thiolase trimetazidine on atherosclerotic plaque development and inflammation.

EXPERIMENTAL APPROACH

The effect of FAO inhibition was determined in LDL-R^-/- male mice on a C57/BL6 background. In vitro effects of trimetazidine treatment were analyzed in human umbilical vein endothelial cells and human monocyte derived macrophages.

KEY RESULTS

We were able to demonstrate that inhibition of FAO reduced atherosclerotic plaque growth. We did not find direct anti-inflammatory properties of trimetazidine in endothelial cells or macrophages in vitro. However, we found that the activation of the NLRP3 system and the secretion of IL-1β were significantly reduced in macrophages after FAO inhibition. These results were confirmed in atherosclerotic lesions of mice treated with trimetazidine as they showed a significant reduction of IL-1β and cleaved caspase-1 in the atherosclerotic lesion as well as of IL-1β and IL-18 in the circulation.

CONCLUSION

Overall, we therefore suggest that the main mechanism of reducing inflammation of trimetazidine and FAO inhibition is the reduction of the NLRP-3 activation leading to reduced levels of the proinflammatory cytokine IL-1β.

Alternative activation of human macrophages enhances tissue factor expression and production of extracellular vesicles

Macrophages are versatile cells that can be polarized by the tissue environment to fulfill required needs. Proinflammatory polarization is associated with increased tissue degradation and propagation of inflammation whereas alternative polarization within a Th2 cytokine environment is associated with wound healing and angiogenesis. To understand whether polarization of macrophages can lead to a procoagulant macrophage subset we polarized human monocyte-derived macrophages to proinflammatory and alternative activation states. Alternative polarization with interleukin-4 and interleukin-13 led to a macrophage phenotype characterized by increased tissue factor (TF) production and release and by an increase in extracellular vesicle production. In addition, TF activity was enhanced in extracellular vesicles of alternatively polarized macrophages. This TF induction was dependent on signal transducer and activator of transcription- 6 signaling and poly ADP ribose polymerase activity. In contrast to monocytes, human macrophages did not show increased TF expression upon stimulation with lipopolysaccharide and interferon-γ. Previous polarization to either a proinflammatory or an alternative activation subset did not change the subsequent stimulation of TF. The inability of proinflammatory activated macrophages to respond to lipopolysaccharide and interferon- γ with an increase in TF production seemed to be due to an increase in TF promoter methylation and was reversible when these macrophages were treated with a demethylating agent. In conclusion, we provide evidence that proinflammatory polarization of macrophages does not lead to enhanced procoagulatory function, whereas alternative polarization of macrophages leads to an increased expression of TF and increased production of TF-bearing extracellular vesicles by these cells suggesting a procoagulatory phenotype of alternatively polarized macrophages.

Mus musculus papillomavirus 1 is a key driver of skin cancer development upon immunosuppression

Epidemiological and experimental data implicate cutaneous human papillomavirus infection as co-factor in the development of cutaneous squamous cell carcinomas (cSCCs), particularly in immunocompromised organ transplant recipients (OTRs). Herein, we established and characterized a skin cancer model, in which Mus musculus papillomavirus 1 (MmuPV1) infection caused cSCCs in cyclosporine A (CsA)-treated mice, even in the absence of UV light. Development of cSCCs and their precursors were observed in 70% of MmuPV1-infected, CsA-treated mice on back as well as on tail skin. Immunosuppression by systemic CsA, but not UV-B irradiation, was a prerequisite, as immunocompetent or UV-B-irradiated mice did not develop skin malignancies after infection. In the virus-driven cSCCs the MmuPV1-E6/E7 oncogenes were abundantly expressed, and transcriptional activity and productive infection demonstrated. MmuPV1 infection induced the expression of phosphorylated H2AX, but not degradation of proapoptotic BAK in the cSCCs. Transfer of primary cells, established from a MmuPV1-induced cSCC from back skin, into athymic nude mice gave rise to secondary cSCCs, which lacked viral DNA, demonstrating that maintenance of the malignant phenotype was virus independent. This papillomavirus-induced skin cancer model opens future investigations into viral involvement, pathogenesis, and cancer surveillance, aiming at understanding and controlling the high incidence of skin cancer in OTRs.

Deficiency of Cathelicidin-related Antimicrobial Peptide Promotes Skin Papillomatosis in Mus musculus Papillomavirus 1-infected Mice

Cathelicidins have been reported to inhibit human papillomavirus infection in vitro; however, nothing is known about their activity in vivo. In this study, experimental skin infection with Mus musculus papillomavirus 1 resulted in robust development of cutaneous papillomas in cyclosporine A-treated C57BL/6J mice deficient for the murine cathelicidin-related antimicrobial peptide (CRAMP), in contrast to wild-type controls. Analysis of the underlying mechanisms revealed moderate disruption of virion integrity and lack of interference with viral entry and intracellular trafficking by a synthetic CRAMP peptide. Differences in the immune response to Mus musculus papillomavirus 1 infection were observed between CRAMP-deficient and wild-type mice. These included a stronger reduction in CD4+ and CD8+ T-cell numbers in infected skin, and lack of Mus musculus papillomavirus 1-specific neutralizing antibodies in response to cyclosporine A in the absence of endogenous CRAMP. CRAMP has modest direct anti-papillomaviral effects in vitro, but exerts protective functions against Mus musculus papillomavirus 1 skin infection and disease development in vivo, primarily by modulation of cellular and humoral immunity.

De novo Vessel Formation Through Cross-Talk of Blood-Derived Cells and Mesenchymal Stromal Cells in the Absence of Pre-existing Vascular Structures

BACKGROUND

The generation of functional blood vessels remains a key challenge for regenerative medicine. Optimized in vitro culture set-ups mimicking the in vivo perivascular niche environment during tissue repair may provide information about the biological function and contribution of progenitor cells to postnatal vasculogenesis, thereby enhancing their therapeutic potential.

AIM

We established a fibrin-based xeno-free human 3D in vitro vascular niche model to study the interaction of mesenchymal stromal cells (MSC) with peripheral blood mononuclear cells (PBMC) including circulating progenitor cells in the absence of endothelial cells (EC), and to investigate the contribution of this cross-talk to neo-vessel formation.

MATERIALS AND METHODS

Bone marrow-derived MSC were co-cultured with whole PBMC, enriched monocytes (Mo), enriched T cells, and Mo together with T cells, respectively, obtained from leukocyte reduction chambers generated during the process of single-donor platelet apheresis. Cells were embedded in 3D fibrin matrices, using exclusively human-derived culture components without external growth factors. Cytokine secretion was analyzed in supernatants of 3D cultures by cytokine array, vascular endothelial growth factor (VEGF) secretion was quantified by ELISA. Cellular and structural re-arrangements were characterized by immunofluorescence and confocal laser-scanning microscopy of topographically intact 3D fibrin gels.

RESULTS

3D co-cultures of MSC with PBMC, and enriched Mo together with enriched T cells, respectively, generated, within 2 weeks, complex CD31+/CD34+ vascular structures, surrounded by basement membrane collagen type-IV+ cells and matrix, in association with increased VEGF secretion. PBMC contained CD31+CD34+CD45dimCD14- progenitor-type cells, and EC of neo-vessels were PBMC-derived. Vascular structures showed intraluminal CD45+ cells that underwent apoptosis thereby creating a lumen. Cross-talk of MSC with enriched Mo provided a pro-angiogenic paracrine environment. MSC co-cultured with enriched T cells formed "cell-in-cell" structures generated through internalization of T cells by CD31+CD45 dim⁣/ - cells. No vascular structures were detected in co-cultures of MSC with either Mo or T cells.

CONCLUSION

Our xeno-free 3D in vitro vascular niche model demonstrates that a complex synergistic network of cellular, extracellular and paracrine cross-talk can contribute to de novo vascular development through self-organization via co-operation of immune cells with blood-derived progenitor cells and MSC, and thereby may open a new perspective for advanced vascular tissue engineering in regenerative medicine.

Neutrophil Extracellular Trap Degradation by Differently Polarized Macrophage Subsets

Supplemental Digital Content is available in the text.

Macrophages are immune cells, capable to remodel the extracellular matrix, which can harbor extracellular DNA incorporated into neutrophil extracellular traps (NETs). To study the breakdown of NETs we studied the capability of macrophage subsets to degrade these structures in vitro and in vivo in a murine thrombosis model. Furthermore, we analyzed human abdominal aortic aneurysm samples in support of our in vitro and in vivo results.

Extracellular Vesicles Derived From Platelets, Red Blood Cells, and Monocyte-Like Cells Differ Regarding Their Ability to Induce Factor XII-Dependent Thrombin Generation

As transmitters of biological information, extracellular vesicles (EVs) are crucial for the maintenance of physiological homeostasis, but also contribute to pathological conditions, such as thrombotic disorders. The ability of EVs to support thrombin generation has been linked to their exposure of phosphatidylserine, an anionic phospholipid that is normally restricted to the inner leaflet of the plasma membrane but exposed on the outer leaflet during EV biogenesis. Here, we investigated whether EVs of different cellular origin and from different settings, namely platelets and red blood cells from blood bank units and a monocyte-like cell line (THP-1), differ regarding their potential to support factor XII-dependent thrombin generation. EVs were isolated from blood products or THP-1 cell culture supernatants using differential centrifugation and characterized by a combination of flow cytometry, nanoparticle tracking analysis, and Western blotting. Soluble factors co-enriched during the isolation of EVs were depleted from blood-cell derived EV fractions using size exclusion chromatography, while proteins bound to the surface of EVs were degraded by mild protease treatment. We found that platelet-derived and red blood cell-derived EVs supported factor XII-dependent thrombin generation to comparable extents, while monocytic EVs failed to support thrombin generation when added to EV-depleted human plasma. We excluded a major contribution of co-enriched soluble proteins or of proteins bound to the EV surface to the thrombogenicity of blood cell-derived EVs. Our data suggest that the enhanced potential of blood cell-derived EVs to support thrombin generation is rather due to enhanced exposure of phosphatidylserine on the surface of blood cell-derived EVs. Extending these investigations to EVs from other cell types, such as mesenchymal stromal cells, will be crucial for their future therapeutic applications.

Influence of Platelet Lysate on 2D and 3D Amniotic Mesenchymal Stem Cell Cultures

The mechanobiological behavior of mesenchymal stem cells (MSCs) in two- (2D) or three-dimensional (3D) cultures relies on the formation of actin filaments which occur as stress fibers and depends on mitochondrial dynamics involving vimentin intermediate filaments. Here we investigate whether human platelet lysate (HPL), that can potentially replace fetal bovine serum for clinical-scale expansion of functional cells, can modulate the stress fiber formation, alter mitochondrial morphology, change membrane elasticity and modulate immune regulatory molecules IDO and GARP in amnion derived MSCs. We can provide evidence that culture supplementation with HPL led to a reduction of stress fiber formation in 2D cultured MSCs compared to a conventional growth medium (MSCGM). 3D MSC cultures, in contrast, showed decreased actin concentrations independent of HPL supplementation. When stress fibers were further segregated by their binding to focal adhesions, a reduction in ventral stress fibers was observed in response to HPL in 2D cultured MSCs, while the length of the individual ventral stress fibers increased. Dorsal stress fibers or transverse arcs were not affected. Interestingly, ventral stress fiber formation did not correlate with membrane elasticity. 2D cultured MSCs did not show differences in the Young's modulus when propagated in the presence of HPL and further cultivation to passage 3 also had no effect on membrane elasticity. In addition, HPL reduced the mitochondrial mass of 2D cultured MSCs while the mitochondrial mass in 3D cultured MSCs was low initially. When mitochondria were segregated into punctuate, rods and networks, a cultivation-induced increase in punctuate and network mitochondria was observed in 2D cultured MSCs of passage 3. Finally, mRNA and protein expression of the immunomodulatory molecule IDO relied on stimulation of 2D culture MSCs with pro-inflammatory cytokines IFN-γ and TNF-α with no effect upon HPL supplementation. GARP mRNA and surface expression was constitutively expressed and did not respond to HPL supplementation or stimulation with IFN-γ and TNF-α. In conclusion, we can say that MSCs cultivated in 2D and 3D are sensitive to medium supplementation with HPL with changes in actin filament formation, mitochondrial dynamics and membrane elasticity that can have an impact on the immunomodulatory function of MSCs.

Protease-Activated Receptors 1 and 3 are Differentially Expressed on Human Monocyte Subsets and are Upregulated by Lipopolysaccharide Ex Vivo and In Vivo

Monocytes are activated in inflammatory conditions via a variety of cytokine receptors as well as in a procoagulatory setting through thrombin, acting upon protease-activated receptors (PARs). This study investigated the expression pattern of PAR1 and PAR3 on human monocyte subsets. Furthermore, a possible regulation of the expression of PAR1 and PAR3 in these cells by inflammatory activation were studied. CD16⁺ monocytes showed significantly higher levels of PAR1 and PAR3 as compared with CD16^- monocytes. Ex vivo treatment of whole blood with lipopolysaccharide (LPS) increased PAR1 and PAR3 messenger ribonucleic acid (mRNA) in human monocytes. In addition, increase of PAR1 was seen in all three subsets upon LPS treatment, whereas PAR3 increased significantly only in CD16^- monocytes and nonclassical CD16⁺ monocytes. Protein levels of PAR1 and PAR3 significantly increased on monocytes in vivo in human endotoxemia 1 hour after LPS infusion. PAR1 increased significantly in CD16^- monocytes and nonclassical CD16⁺ monocytes. In this in vivo model, PAR3 was also significantly elevated in CD16^- monocytes and increased slightly albeit not significantly in CD16⁺ monocytes. Endotoxemia increased plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) expression in monocytes in humans. Pretreatment of healthy volunteers with the PAR1 antagonist vorapaxar blocked the increase in PAI-1 but not the increase in TF. We here provide new evidence for a critical role for monocytes as cellular mediators that contribute to the activation of coagulation in diseases characterized by an inflammatory state.

Hypomorphic Mutations in the BCR Signalosome Lead to Selective Immunoglobulin M Deficiency and Impaired B-cell Homeostasis

B cell activation via the B cell receptor (BCR) signalosome involves participation of signaling molecules such as BTK and BLNK. Genetic defects in these molecules are known to impair B cell differentiation and subsequently lead to agammaglobulinemia. Here we identified novel mutations in BTK and BLNK in two unrelated patients that perturb the intrinsic B-cell receptor signaling pathway and lead to selective IgM deficiency, whereas production of other immunoglobulin isotypes and IgG antibody response remain intact. Currently it is unknown how BCR signaling strength affects mature B cell development in humans. Both patients show reduced levels of BCR signalosome phosphorylation as well as impaired BCR-dependent Ca²⁺ influx, which was accompanied by a marked decrease in IgD⁺IgM⁺CD27⁺ MZ-like B-cells. We further describe reduced expression of essential B cell differentiation factors such as BAFF-R and T-Bet in the patients' B-cells, which might contribute to the observed deficiency of MZ-like B cells. MZ-like B cells are known to produce natural IgM antibodies that play an essential role in immune homeostasis. By using surface plasmon resonance (SPR) technology and a synthetic blood group A trisaccharide as antigen we were able to show that both patients lack the presence of anti-blood group A IgM considered to be prototypical natural antibodies whereas IgG levels were normal. Antibody binding dynamics and binding affinity of anti-blood group A IgG were comparable between patients and healthy controls. These results indicate that human IgM deficiency can be associated with signaling defects in the BCR signalosome, defective production of natural IgM antibodies in the blood group A/B/0 system and abnormalities in B cell development.

Differential Interaction of Platelet-Derived Extracellular Vesicles With Circulating Immune Cells: Roles of TAM Receptors, CD11b, and Phosphatidylserine

Secretion and exchange of biomolecules by extracellular vesicles (EVs) are crucial in intercellular communication and enable cells to adapt to alterations in their microenvironment. EVs are involved in a variety of cellular processes under physiological conditions as well as in pathological settings. In particular, they exert profound effects on the innate immune system, and thereby are also capable of modulating adaptive immunity. The mechanisms underlying their interaction with their recipient cells, particularly their preferential association with monocytes and granulocytes in the circulation, however, remain to be further clarified. Surface molecules exposed on EVs are likely to mediate immune recognition and EV uptake by their recipient cells. Here, we investigated the involvement of Tyro3, Axl, and Mer (TAM) tyrosine kinase receptors and of integrin CD11b in the binding of platelet-derived EVs, constituting the large majority of circulating EVs, to immune cells in the circulation. Flow cytometry and Western Blotting demonstrated a differential expression of TAM receptors and CD11b on monocytes, granulocytes, and lymphocytes, as well as on monocyte subsets. Of the TAM receptors, only Axl and Mer were detected at low levels on monocytes and granulocytes, but not on lymphocytes. Likewise, CD11b was present on circulating monocytes and granulocytes, but remained undetectable on lymphocytes. Differentiation of monocytes into classical, intermediate, and non-classical monocyte subsets revealed distinct expression patterns of Mer and activated CD11b. Co-incubation of isolated monocytes and granulocytes with platelet-derived EVs showed that the binding of EVs to immune cells was dependent on Ca⁺⁺. Our data do not support a particular role for TAM receptors or for activated CD11b in the association of platelet-derived EVs with monocytes and granulocytes in the circulation, as anti-TAM antibodies did not interfere with EV binding to isolated immune cells, as binding was not dependent on the presence of TIM4 acting synergistically with TAM receptors, and as neither low levels of Gas6, required as a linker between phosphatidylserine (PS) on the EV surface and TAM receptors on immune cells, nor masking of PS on the EV surface did interfere with EV binding.

Audencel Immunotherapy Based on Dendritic Cells Has No Effect on Overall and Progression-Free Survival in Newly Diagnosed Glioblastoma: A Phase II Randomized Trial

Dendritic cells (DCs) are antigen-presenting cells that are capable of priming anti-tumor immune responses, thus serving as attractive tools to generate tumor vaccines. In this multicentric randomized open-label phase II study, we investigated the efficacy of vaccination with tumor lysate-charged autologous DCs (Audencel) in newly diagnosed glioblastoma multiforme (GBM). Patients aged 18 to 70 years with histologically proven primary GBM and resection of at least 70% were randomized 1:1 to standard of care (SOC) or SOC plus vaccination (weekly intranodal application in weeks seven to 10, followed by monthly intervals). The primary endpoint was progression-free survival at 12 months. Secondary endpoints were overall survival, safety, and toxicity. Seventy-six adult patients were analyzed in this study. Vaccinations were given for seven (3⁻20) months on average. No severe toxicity was attributable to vaccination. Seven patients showed flu-like symptoms, and six patients developed local skin reactions. Progression-free survival at 12 months did not differ significantly between the control and vaccine groups (28.4% versus 24.5%, p = 0.9975). Median overall survival was similar with 18.3 months (vaccine: 564 days, 95% CI: 436⁻671 versus control: 568 days, 95% CI: 349⁻680; p = 0.89, harzard ratio (HR) 0.99). Hence, in this trial, the clinical outcomes of patients with primary GBM could not be improved by the addition of Audencel to SOC.

Vascular Morphogenesis in the Context of Inflammation: Self-Organization in a Fibrin-Based 3D Culture System

Introduction: New vessel formation requires a continuous and tightly regulated interplay between endothelial cells with cells of the perivascular microenvironment supported by mechanic-physical and chemical cues from the extracellular matrix. Aim: Here we investigated the potential of small fragments of synovial tissue to form de novo vascular structures in the context of inflammation within three dimensional (3D) fibrin-based matrices in vitro, and assessed the contribution of mesenchymal stromal cell (MSC)-immune cell cross-talk to neovascularization considering paracrine signals in a fibrin-based co-culture model. Material and Methods: Synovial tissue fragments from patients with rheumatoid arthritis (RA) and inflammatory osteoarthritis (OA) were cultivated within 3D fibrin matrices for up to 4 weeks. Cellular and structural re-arrangement of the initially acellular matrix were documented by phase contrast microscopy and characterized by confocal laser-scanning microscopy of topographically intact 3D cultures and by immunohistochemistry. MSC-peripheral blood mononuclear cell (PBMC) co-cultures in the 3D fibrin system specifically addressed the influence of perivascular cell interactions to neo-vessel formation in a pro-inflammatory microenvironment. Cytokine levels in the supernatants of cultured explant tissues and co-cultures were evaluated by the Bio-Plex cytokine assay and ELISA. Results: Vascular outgrowth from the embedded tissue into the fibrin matrix was preceded by leukocyte egress from the tissue fragments. Neo-vessels originating from both the embedded sample and from clusters locally formed by emigrated mononuclear cells were consistently associated with CD45⁺ leukocytes. MSC and PBMC in co-culture formed vasculogenic clusters. Clusters and cells with endothelial phenotype emerging from them, were surrounded by a collagen IV scaffold. No vascular structures were observed in control 3D monocultures of PBMC or MSC. Paracrine signals released by cultured OA tissue fragments corresponded with elevated levels of granulocyte-colony stimulating factor, vascular endothelial growth factor and interleukin-6 secreted by MSC-PBMC co-cultures. Conclusion: Our results show that synovial tissue fragments with immune cell infiltrates have the potential to form new vessels in initially avascular 3D fibrin-based matrices. Cross-talk and cluster formation of MSC with immune cells within the 3D fibrin environment through self-organization and secretion of pro-angiogenic paracrine factors can support neo-vessel growth.

Canine macrophages can like human macrophages be in vitro activated toward the M2a subtype relevant in allergy

The M2a subtype of macrophages plays an important role in human immunoglobulin E (IgE-mediated allergies) and other Th2 type immune reactions. In contrast, very little is known about these cells in the dog. Here we describe an in vitro method to activate canine histiocytic DH82 cells and primary canine monocyte-derived macrophages (MDMs) toward the M2a macrophages using human cytokines. For a side-by-side comparison, we compared the canine cells to human MDMs, and the human monocytic cell line U937 activated towards M1 and M2a cells on the cellular and molecular level. In analogy to activated human M2a cells, canine M2a, differentiated from both DH82 and MDMs, showed an increase in CD206 surface receptor expression compared to M1. Interestingly, canine M2a, but not M1 derived from MDM, upregulated the high-affinity IgE receptor (FcεRI). Transcription levels of M2a-associated genes (IL10, CCL22, TGFβ, CD163) showed a diverse pattern between the human and dog species, whereas M1 genes (IDO1, CXCL11, IL6, TNF-α) were similarly upregulated in canine and human M1 cells (cell lines and MDMs). We suggest that our novel in vitro method will be suitable in comparative allergology studies focussing on macrophages.

Extracellular Purine Metabolism Is the Switchboard of Immunosuppressive Macrophages and a Novel Target to Treat Diseases With Macrophage Imbalances

If misregulated, macrophage (Mϕ)-T cell interactions can drive chronic inflammation thereby causing diseases, such as rheumatoid arthritis (RA). We report that in a proinflammatory environment, granulocyte-Mϕ (GM-CSF)- and Mϕ colony-stimulating factor (M-CSF)-dependent Mϕs have dichotomous effects on T cell activity. While GM-CSF-dependent Mϕs show a highly stimulatory activity typical for M1 Mϕs, M-CSF-dependent Mϕs, marked by folate receptor β (FRβ), adopt an immunosuppressive M2 phenotype. We find the latter to be caused by the purinergic pathway that directs release of extracellular ATP and its conversion to immunosuppressive adenosine by co-expressed CD39 and CD73. Since we observed a misbalance between immunosuppressive and immunostimulatory Mϕs in human and murine arthritic joints, we devised a new strategy for RA treatment based on targeted delivery of a novel methotrexate (MTX) formulation to the immunosuppressive FRβ⁺CD39⁺CD73⁺ Mϕs, which boosts adenosine production and curtails the dominance of proinflammatory Mϕs. In contrast to untargeted MTX, this approach leads to potent alleviation of inflammation in the murine arthritis model. In conclusion, we define the Mϕ extracellular purine metabolism as a novel checkpoint in Mϕ cell fate decision-making and an attractive target to control pathological Mϕs in immune-mediated diseases.

Effect of intravenous immunoglobulin administration on erythrocyte and leucocyte parameters

BACKGROUND

Intravenous immunoglobulins (IVIG) are an attractive therapeutic tool for therapy of toxic epidermal necrolysis and severe forms of certain autoimmune diseases, including dermatomyositis, autoimmune blistering diseases, systemic vasculitis and lupus erythematodes.

OBJECTIVES

Prompted by a case of IVIG-associated haemolytic anaemia, the effects of IVIG administrations on haematological parameters in patients with dermatological conditions were investigated.

METHODS

Erythrocyte and leucocyte parameters were retrospectively analysed in 16 patients who had received IVIG at doses from 1 to 3 g/kg bodyweight (n = 35 cycles). The influence of IVIG on leucocyte survival was determined in vitro.

RESULTS

Decreased absolute erythrocyte numbers, haemoglobin and haematocrit levels and a case of haemolytic anaemia were linked to transfusion of high-, but not low-dose IVIG. In contrast, leucopenia post-IVIG occurred in the vast majority of the recipients, unrelated to the administered IVIG amounts. In vitro investigations revealed a dose-dependent impairment of cell survival by IVIG in the neutrophil and monocyte, but not in the lymphocyte subpopulations. In several IVIG preparations, substantial amounts of blood group anti-A/anti-B antibodies were detected which could have accounted for the observed changes in the haematological parameters in our study cohort.

CONCLUSIONS

IVIG products should be administered strictly according to indications. Commercially available IVIG products can contain blood group-specific antibodies that may induce haemolysis in some recipients. Monitoring of blood counts during applied IVIG therapy, especially when high doses are administered, is recommended.

Development of a Multifunctional Nanobiointerface Based on Self-Assembled Fusion-Protein rSbpA/ZZ for Blood Cell Enrichment and Phenotyping

We present a multifunctional nanobiointerface for blood cell capture and phenotyping applications that features both excellent antifouling properties and high antibody activity. Multifunctionality is accomplished by modifying polymeric materials using self-assembled S-layer fusion-protein rSbpA/ZZ to immobilize high density antibodies at the two protein A binding sites of the rSbpA/ZZ nanolattice structure. Controlled orientation and alignment of the antibodies reduced antibody consumption 100-fold and increased cell capture efficiency 4-fold over standard methodologies. Cell analysis in complex samples was made possible by the remarkable antifouling properties of the rSbpA domain, while at the same time reducing unspecific binding and forgoing tedious blocking procedures. An automated microfluidic in situ cell analysis platform for isolation and phenotyping of primary peripheral blood mononuclear cells was developed as practical application. Results obtained using our automated microfluidic cell analysis platform showed that the multifunctional nanobiointerface can discriminate among T helper and cytotoxic T cells, and thymocytes. Additionally, on-chip cell capture under flow conditions using a high affinity CD 3 selective nanobiointerface preferentially isolated cells with strong surface marker expression. This means that our dynamic microfluidic cell purification method allows the enrichment of 773 CD 8 positive cytotoxic T cells out of a total blood cell population of 7728 PBMCs, which is an increase in cell enrichment of 8-fold with a purity of 85%.

PAI-1 (Plasminogen Activator Inhibitor-1) Expression Renders Alternatively Activated Human Macrophages Proteolytically Quiescent

OBJECTIVE

Macrophages are versatile immune cells capable of polarizing into functional subsets depending on environmental stimulation. In atherosclerotic lesions, proinflammatory polarized macrophages are associated with symptomatic plaques, whereas Th2 (T-helper cell type 2) cytokine-polarized macrophages are inversely related with disease progression. To establish a functional cause for these observations, we analyzed extracellular matrix degradation phenotypes in polarized macrophages.

APPROACH AND RESULTS

We provide evidence that proinflammatory polarized macrophages rely on membrane-bound proteases including MMP-14 (matrix metalloproteinase-14) and the serine protease uPA (urokinase plasminogen activator) together with its receptor uPAR for extracellular matrix degradation. In contrast, Th2 cytokine alternatively primed macrophages do not show different proteolytic activity in comparison to unpolarized macrophages and lack increased localization of MMP-14 and uPA receptor to the cell membrane. Nonetheless, they express the highest amount of the serine protease uPA. However, uPA activity is blocked by similarly increased expression of its inhibitor PAI-1 (plasminogen activator inhibitor 1). When inhibiting PAI-1 or when analyzing macrophages deficient in PAI-1, Th2 cytokine-polarized macrophages display the same matrix degradation capability as proinflammatory-primed macrophages. Within atherosclerotic lesions, macrophages positive for the alternative activation marker CD206 express high levels of PAI-1. In addition, to test changed tissue remodeling capacities of alternatively activated macrophages, we used a bleomycin lung injury model in mice reconstituted with PAI-1^-/- bone marrow. These results supported an enhanced remodeling phenotype displayed by increased fibrosis and elevated MMP activity in the lung after PAI-1 loss.

CONCLUSIONS

We were able to demonstrate matrix degradation dependent on membrane-bound proteases in proinflammatory stimulated macrophages and a forced proteolytical quiescence in alternatively polarized macrophages by the expression of PAI-1.

A New Method Using Autogenous Impacted Third Molars for Sinus Augmentation to Enhance Implant Treatment: Case Series with Preliminary Results of an Open, Prospective Longitudinal Study

PURPOSE

This prospective longitudinal study reports on the results in patients given autologous tooth material for augmentation in a sinus elevation procedure.

MATERIALS AND METHODS

Six patients with inadequate bone supply for augmentation in the maxillary posterior tooth region and at least one impacted maxillary third molar underwent sinus elevation surgery with lateral access using the particulate tooth material. One of the patients received four implants during the same session, while the other patients had a total of 15 implants placed after a healing phase of an average 5.5 months. Drill cylinders collected from the implant bed during the procedure were subjected to histologic/immunohistochemical evaluation.

RESULTS

All six patients showed normal and unobtrusive postoperative healing, having undergone prosthetic restoration up to 5 years before. The average peri-implant probing pocket depth after a period of up to 5 years ranged between 1.86 mm (mesial and lingual) and 2.07 mm (distal and buccal). No bleeding could be triggered with any of the peri-implant probes. The average peri-implant bone resorption measured during the first year was up to 0.63 mm, with the lowest being 0 mm and the maximum 2.9 mm. Peri-implant bone remained stable for the follow-up time of up to 5 years. Histologically, six biopsy specimens collected from five patients showed osteoconductive osteogenesis with encapsulation of tooth enamel and dentin portions and partial resorption of the tooth components. Cementum shares were no longer discernible. Immunohistochemical assessment showed intense new vessel formation that could be observed in the area of loose stroma of reorganized tissue in the augmented area.

CONCLUSION

Within the limits of these preliminary results and with adequate consideration of the small number of patients included, the use of autogenous crushed tooth material from impacted third molars may represent an alternative augmentation material for use in sinus elevation procedures.

Release kinetics and mitogenic capacity of collagen barrier membranes supplemented with secretome of activated platelets - the in vitro response of fibroblasts of the periodontal ligament and the gingiva

Background

Platelet preparations can stimulate the healing process and have mitogenic properties. We hypothesized that collagen barrier membranes (CBM), clinically used in guided bone regeneration and guided tissue regeneration, can serve as carriers for platelet secretome.

Methods

Secretome was generated from washed platelets and unwashed platelets (washed/unwashed PSEC) and lyophilized onto CBM. Overall appearance of CBM was evaluated by scanning electron microscopy. The impact of PSEC on cell attachment was measured based on fluorescence microscopy with DiI-labeled cells. To assess the release kinetics, supernatants of CBM were collected and medium was replaced at hour 1–48. The mitogenic effect was evaluated with periodontal fibroblasts. Furthermore, the release of total protein, platelet-derived growth factor (PDGF)-BB, and transforming growth factor (TGF) β1 was measured.

Results

CBM overall appearance and cell attachment was not modulated by PSEC. Supernatants taken after one hour induced a mitogenic response in fibroblasts and showed the highest levels of total protein, TGFβ1 and PDGF-BB. These effects decreased rapidly in subsequent supernatants. While supernatants of CBM loaded with unwashed PSEC induced a stronger mitogenic response than supernatants of CBM loaded with washed PSEC this difference between the PSEC preparations was not observed when cells were seeded on 48–hours-washed CBM.

Conclusions

CBM release platelet-derived factors in continuously declining release kinetics.

The impact of citrate concentration on adhesion of platelets and leukocytes to adsorbents in whole blood lipoprotein apheresis

Lipoprotein apheresis is applied to deplete low density lipoprotein and other apolipoprotein B containing lipoproteins in patients with severe familial hypercholesterolemia, hypertriglyceridemia associated pancreatitis, or lipoprotein (a)-hyperlipoproteinemia. Anticoagulation of the extracorporeal circuit may influence cellular activation, as evidenced by a reduction of inflammatory parameters during regional citrate anticoagulation with acid citrate dextrose A (ACD-A) commonly used in whole blood lipid apheresis. While the citrate concentration in the extracorporeal circuit has to ensure efficient anticoagulation, citrate infusion into the patient should be limited to avoid citrate overload. We assessed the influence of citrate concentration on cellular activation during in vitro circulation of whole blood containing 2.8 mM citrate (ACD-A 1:40), 5.6 mM citrate (ACD-A 1:20), or 13 mM citrate over polyacrylate-based adsorbents for lipoprotein apheresis. We found increased platelet adhesion for anticoagulation with 2.8 mM citrate as compared to 5.6 or 13 mM citrate, as shown by cell counting and confirmed by scanning electron microscopy of adsorbent beads as well as by elevated levels of platelet activation markers and of platelet-derived microvesicles. Leukocytes showed an equivalent adhesion pattern, while red blood cells remained unaffected at all citrate concentrations. Passage of blood over two consecutive columns resulted in enhanced platelet adhesion to the second column, presumably due to upstream preactivation. In conclusion, citrate influences activation and adhesion of platelets and leukocytes in a concentration-dependent manner, and ACD-A 1:20, equivalent to a citrate concentration of 5.6 mM in whole blood, ensures minimal cellular activation during passage of whole blood over polyacrylate-based adsorbents.

Pneumococcal Polysaccharide Vaccination Elicits IgG Anti-A/B Blood Group Antibodies in Healthy Individuals and Patients with Type I Diabetes Mellitus

Hypothesis

Blood group antibodies are natural antibodies that develop early in life in response to cross-reactive environmental antigens in the absence of antigen encounter. Even later in life structural similarities in saccharide composition between environmental antigens such as bacterial polysaccharides and blood group A/B antigens could lead to changes in serum levels, IgM/IgG isotype, and affinity maturation of blood group anti-A/B antibodies. We addressed the question whether immunization with pneumococcal polysaccharide (PnP) vaccine Pneumo 23 Vaccine “Pasteur Merieux” (Pn23) could have such an effect in patients with type I diabetes mellitus (DM I), an autoimmune disease where an aberrant immune response to microbial antigens likely plays a role.

Methods

Anti-PnP IgM and IgG responses were determined by ELISA, and the DiaMed-ID Micro Typing System was used to screen anti-A/B antibody titer before and after Pn23 immunization in 28 healthy individuals and 16 patients with DM I. In addition, surface plasmon resonance (SPR) technology using the Biacore^® device and a synthetic blood group A/B trisaccharide as the antigen was applied to investigate IgM and IgG anti-A/B antibodies and to measure antibody binding dynamics.

Results

All healthy individuals and DM I patients responded with anti-PnP IgM and IgG antibody production 4–6 weeks after Pn23 immunization, while no increase in blood group anti-A/B antibody titer was observed when measured by the DiaMed-ID Micro Typing System. Interestingly, isotype-specific testing by SPR technology revealed an increase in blood group anti-A/B IgG, but not IgM, following Pn23 immunization in both patients and controls. No change in binding characteristics of blood group anti-A/B antibodies could be detected following Pn23 vaccination, supporting the assumption of an increase in IgG antibody titer with no or very little affinity maturation.

Conclusion

The study provides evidence for epitope sharing between pneumococcal polysaccharides and blood group ABO antigens, which leads to a booster of blood group anti-A/B antibodies of the IgG isotype after Pn23 immunization in healthy individuals. Manifest autoimmunity such as present in DM I patients has no additional effect on the cross-reactive antibody response against pneumococcal polysaccharides and blood group antigens.

Differentiation of human monocytes and derived subsets of macrophages and dendritic cells by the HLDA10 monoclonal antibody panel

The mononuclear phagocyte system, consisting of monocytes, macrophages and dendritic cells (DCs), has an important role in tissue homeostasis as well as in eliciting immune responses against invading pathogens. Blood monocytes have been viewed for decades as precursors of tissue macrophages. Although the newest data show that in the steady state resident macrophages of many organs are monocyte independent, blood monocytes critically contribute to tissue macrophage and DC pools upon inflammation. To better understand the relationship between these populations and their phenotype, we isolated and differentiated human blood CD14⁺ monocytes in vitro into immature and mature monocyte-derived dendritic cells (MoDCs) as well as into seven different monocyte-derived macrophage subsets. We used the panel of 70 monoclonal antibodies (mAbs) submitted to the 10th Human Leukocyte Differentiation Antigen Workshop to determine the expression profiles of these 10 populations by flow cytometry. We now can compile subpanels of mAbs to differentiate the 10 monocyte/macrophage/MoDC subsets, providing the basis for novel diagnostic and therapeutic tools.

Association of HER2 codon 655 polymorphism with ovarian cancer

The role of the human epidermal growth factor receptor 2 (HER2) codon 655 (Ile655Val) polymorphism in ovarian cancer is not fully understood. Two studies indicated a possible association between the Val allele and elevated risk or reduced prognosis of ovarian cancer. We investigated the HER2 codon 655 (rs1136201) polymorphism in 242 Austrian women-142 ovarian cancer patients and 100 healthy controls-by polymerase chain reaction and pyrosequencing. Associations between Ile655Val polymorphism and clinicopathological variables (e.g., age, FIGO stage, grading, serous vs. non-serous histology) were evaluated. The genotype distributions in ovarian cancer patients and controls were: AA; 66.2 %, AG; 25.35 %, GG; 8.45 %, and AA; 63 %, AG; 34 %, GG; 3.7 %, respectively (OR 1.15, CI 95 % 0.67-1.96). We observed a non-significant trend toward elevated cancer risk in Val/Val genotype (OR 2.98, CI 95 % 0.82-10.87, p = 0.10). Of note, 11 out of 12 Val/Val homozygotes were postmenopausal. The link between the Val/Val homozygosity and age over 50 years at diagnosis (OR 0.15, CI 95 % 0.02-1.2) was barely significant (p = 0.056). Summarizing, our data indicated a non-significant trend toward increased ovarian cancer risk in the Val/Val homozygosity, especially in women aged above 50 years. Further large-cohort studies focusing on the role of the HER2 codon 655 Val allele are needed.

Release and cellular origin of extracellular vesicles during circulation of whole blood over adsorbent polymers for lipid apheresis

Whole blood lipid apheresis is clinically applied in patients with familial hypercholesterolemia to reduce low density lipoprotein and other apolipoprotein B 100 containing lipoproteins. Here, the hemocompatibility of two polyacrylate-coated polyacrylamide-based polymers for lipid apheresis by evaluating the adhesion of blood cells to the adsorbent polymers, their respective activation, as well as the release of microvesicles during circulation of whole blood over the polymers was studied. Characterization of the adsorbents by scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy revealed differences with respect to their surface morphology and their surface chemical composition. Despite these differences, equivalent amounts of leukocytes and platelets adhered to both polymers during circulation of whole blood over the adsorbent columns. The release of phosphatidylserine-exposing microvesicles, in contrast, increased significantly with increasing surface roughness and with the amount of polyacrylate groups at the adsorbent surface. The majority of microvesicles generated during blood-material contact were platelet-derived, and their release was associated with enhanced thrombin generation. Microvesicles were present in free and in cell-bound form, and 75% of all monocytes, but only 0.2% and 2.3% of red blood cells and platelets, respectively, were associated with microvesicles, pointing to a role of monocytes in the clearance of released microvesicles. Taken together, microvesicles are sensitive indicators for biomaterial-induced activation of blood cells in apheresis. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 636-646, 2017.

HER2 Codon 655 (Ile/Val) Polymorphism and Breast Cancer in Austrian Women

BACKGROUND

The overexpression of the human epidermal growth factor receptor 2 (HER2) in breast cancer (BC) is associated with impaired prognosis. Data concerning the HER2 codon 655 polymorphism (Ile/Val) and BC risk are conflicting.

MATERIALS AND METHODS

We studied the HER2 codon 655 (rs1136201) polymorphism in 80 Austrian patients with BC and 100 healthy volunteers by pyrosequencing and polymerase chain reaction. Associations between codon 655 allelic variants and clinicopathological variables (e.g. age, stage of disease, tumor type, grading, and receptor status) were studied with 2×2 tables.

RESULTS

The genotypic distributions in patients with BC (AA: 63.75%, AG: 32.5%, GG: 3.75%) and controls (AA: 63%, AG: 34%, GG: 3.7%) were virtually identical (odds ratio=1.03, 95% confidence interval=0.56-1.90). A non-significant link between carrying at least one G allele and more aggressive tumor type (estrogen receptor-negative p=0.08, G3 tumor p=0.19) was observed.

CONCLUSION

Genotypic variation within the codon 655 of HER2 does not alter the BC risk in Caucasian Austrian women. The association between the G allele and more aggressive tumor types requires further investigation.

M2 Polarization of Human Macrophages Favors Survival of the Intracellular Pathogen Chlamydia pneumoniae

Intracellular pathogens have developed various strategies to escape immunity to enable their survival in host cells, and many bacterial pathogens preferentially reside inside macrophages, using diverse mechanisms to penetrate their defenses and to exploit their high degree of metabolic diversity and plasticity. Here, we characterized the interactions of the intracellular pathogen Chlamydia pneumoniae with polarized human macrophages. Primary human monocytes were pre-differentiated with granulocyte macrophage colony-stimulating factor or macrophage colony-stimulating factor for 7 days to yield M1-like and M2-like macrophages, which were further treated with interferon-γ and lipopolysaccharide or with interleukin-4 for 48 h to obtain fully polarized M1 and M2 macrophages. M1 and M2 cells exhibited distinct morphology with round or spindle-shaped appearance for M1 and M2, respectively, distinct surface marker profiles, as well as different cytokine and chemokine secretion. Macrophage polarization did not influence uptake of C. pneumoniae, since comparable copy numbers of chlamydial DNA were detected in M1 and M2 at 6 h post infection, but an increase in chlamydial DNA over time indicating proliferation was only observed in M2. Accordingly, 72±5% of M2 vs. 48±7% of M1 stained positive for chlamydial lipopolysaccharide, with large perinuclear inclusions in M2 and less clearly bordered inclusions for M1. Viable C. pneumoniae was present in lysates from M2, but not from M1 macrophages. The ability of M1 to restrict chlamydial replication was not observed in M1-like macrophages, since chlamydial load showed an equal increase over time for M1-like and M2-like macrophages. Our findings support the importance of macrophage polarization for the control of intracellular infection, and show that M2 are the preferred survival niche for C. pneumoniae. M1 did not allow for chlamydial proliferation, but failed to completely eliminate chlamydial infection, giving further evidence for the ability of C. pneumoniae to evade cellular defense and to persist in human macrophages.

HER2 Codon 655 (Ile/Val) Polymorphism and Breast Cancer in Austrian Women

BACKGROUND

The overexpression of the human epidermal growth factor receptor 2 (HER2) in breast cancer (BC) is associated with impaired prognosis. Data concerning the HER2 codon 655 polymorphism (Ile/Val) and BC risk are conflicting.

MATERIALS AND METHODS

We studied the HER2 codon 655 (rs1136201) polymorphism in 80 Austrian patients with BC and 100 healthy volunteers by pyrosequencing and polymerase chain reaction. Associations between codon 655 allelic variants and clinicopathological variables (e.g. age, stage of disease, tumor type, grading, and receptor status) were studied with 2×2 tables.

RESULTS

The genotypic distributions in patients with BC (AA: 63.75%, AG: 32.5%, GG: 3.75%) and controls (AA: 63%, AG: 34%, GG: 3.7%) were virtually identical (odds ratio=1.03, 95% confidence interval=0.56-1.90). A non-significant link between carrying at least one G allele and more aggressive tumor type (estrogen receptor-negative p=0.08, G3 tumor p=0.19) was observed.

CONCLUSION

Genotypic variation within the codon 655 of HER2 does not alter the BC risk in Caucasian Austrian women. The association between the G allele and more aggressive tumor types requires further investigation.

Surface Plasmon Resonance Analysis Shows an IgG-Isotype-Specific Defect in ABO Blood Group Antibody Formation in Patients with Common Variable Immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID) is the most common clinically severe primary immunodeficiency and comprises a heterogeneous group of patients with recurrent severe bacterial infections due to the failure to produce IgG antibodies after exposure to infectious agents and immunization. Diagnostic recommendations for antibody failure include assessment of isoagglutinins. We have readdressed this four decades old but still accepted recommendation with up to date methodology.

METHODS

Anti-A/B IgM- and IgG-antibodies were measured by Diamed-ID Micro Typing, surface plasmon resonance (SPR) using the Biacore(®) device and flow cytometry.

RESULTS

When Diamed-ID Micro Typing was used, CVID patients (n = 34) showed IgG- and IgM-isoagglutinins that were comparable to healthy volunteers (n = 28), while all XLA patients (n = 8) had none. Anti-A/B IgM-antibodies were present in more than 2/3 of the CVID patients and showed binding kinetics comparable to anti-A/B IgM-antibodies from healthy individuals. A correlation could be found in CVID patients between levels of anti-A/B IgM-antibodies and levels of serum IgM and PnP-IgM-antibodies. In contrast in CVID patients as a group ABO antibodies were significantly decreased when assessed by SPR, which correlated with levels of switched memory, non-switched memory and naïve B cells, but all CVID patients had low/undetectable anti-A/B IgG-antibodies.

CONCLUSION

These results indicate that conventional isoagglutinin assessment and assessment of anti-A/B IgM antibodies are not suited for the diagnosis of impaired antibody production in CVID. Examination of anti-A/B IgG antibodies by SPR provides a useful method for the diagnosis of IgG antibody failure in all CVID patients studied, thus indicating an important additional rationale to start immunoglobulin replacement therapy early in these patients, before post-infectious sequelae develop.

The secretome of apoptotic human peripheral blood mononuclear cells attenuates secondary damage following spinal cord injury in rats

After spinal cord injury (SCI), secondary damage caused by oxidative stress, inflammation, and ischemia leads to neurological deterioration. In recent years, therapeutic approaches to trauma have focused on modulating this secondary cascade. There is increasing evidence that the success of cell-based SCI therapy is due mainly to secreted factors rather than to cell implantation per se. This study investigated peripheral blood mononuclear cells as a source of factors for secretome- (MNC-secretome-) based therapy. Specifically, we investigated whether MNC-secretome had therapeutic effects in a rat SCI contusion model and its possible underlying mechanisms. Rats treated with MNC-secretome showed substantially improved functional recovery, attenuated cavity formation, and reduced acute axonal injury compared to control animals. Histological evaluation revealed higher vascular density in the spinal cords of treated animals. Immunohistochemistry showed that MNC-secretome treatment increased the recruitment of CD68(+) cells with concomitant reduction of oxidative stress as reflected by lower expression of inducible nitric oxide synthase. Notably, MNC-secretome showed angiogenic properties ex vivo in aortic rings and spinal cord tissue, and experiments showed that the angiogenic potential of MNC-secretome may be regulated by CXCL-1 upregulation in vivo. Moreover, systemic application of MNC-secretome activated the ERK1/2 pathway in the spinal cord. Taken together, these results indicate that factors in MNC-secretome can mitigate the pathophysiological processes of secondary damage after SCI and improve functional outcomes in rats.

Circulating microparticles carry oxidation-specific epitopes and are recognized by natural IgM antibodies

Oxidation-specific epitopes (OSEs) present on apoptotic cells and oxidized low density lipoprotein (OxLDL) represent danger-associated molecular patterns that are recognized by different arcs of innate immunity, including natural IgM antibodies. Here, we investigated whether circulating microparticles (MPs), which are small membrane vesicles released by apoptotic or activated cells, are physiological carriers of OSEs. OSEs on circulating MPs isolated from healthy donors and patients with ST-segment elevation myocardial infarction (STE-MI) were characterized by flow cytometry using a panel of OSE-specific monoclonal antibodies. We found that a subset of MPs carry OSEs on their surface, predominantly malondialdehyde (MDA) epitopes. Consistent with this, a majority of IgM antibodies bound on the surface of circulating MPs were found to have specificity for MDA-modified LDL. Moreover, we show that MPs can stimulate THP-1 (human acute monocytic leukemia cell line) and human primary monocytes to produce interleukin 8, which can be inhibited by a monoclonal IgM with specificity for MDA epitopes. Finally, we show that MDA⁺ MPs are elevated at the culprit lesion site of patients with STE-MI. Our results identify a subset of OSE⁺ MPs that are bound by OxLDL-specific IgM. These findings demonstrate a novel mechanism by which anti-OxLDL IgM antibodies could mediate protective functions in CVD.

Human blood monocytes support persistence, but not replication of the intracellular pathogen C. pneumoniae

Background

Intracellular pathogens have devised various mechanisms to subvert the host immune response in order to survive and replicate in host cells. Here, we studied the infection of human blood monocytes with the intracellular pathogen C. pneumoniae and the effect on cytokine and chemokine profiles in comparison to stimulation with LPS.

Results

Monocytes purified from peripheral blood mononuclear cells by negative depletion were infected with C. pneumoniae. While immunofluorescence confirmed the presence of chlamydial lipopolysaccharide (LPS) in the cytoplasm of infected monocytes, real-time PCR did not provide evidence for replication of the intracellular pathogen. Complementary to PCR, C. pneumoniae infection was confirmed by an oligonucleotide DNA microarray for the detection of intracellular pathogens. Raman microspectroscopy revealed different molecular fingerprints for infected and non-infected monocytes, which were mainly due to changes in lipid and fatty acid content. Stimulation of monocytes with C. pneumoniae or with LPS induced similar profiles of tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6, but higher levels of IL-1β, IL-12p40 and IL-12p70 for C. pneumoniae which were statistically significant. C. pneumoniae also induced release of the chemokines MCP-1, MIP-1α and MIP-1β, and CXCL-8, which correlated with TNF-α secretion.

Conclusion

Infection of human blood monocytes with intracellular pathogens triggers altered cytokine and chemokine pattern as compared to stimulation with extracellular ligands such as LPS. Complementing conventional methods, an oligonucleotide DNA microarray for the detection of intracellular pathogens as well as Raman microspectroscopy provide useful tools to trace monocyte infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-014-0060-1) contains supplementary material, which is available to authorized users.

Vascularization of primary and secondary ossification centres in the human growth plate

Background

The switch from cartilage template to bone during endochondral ossification of the growth plate requires a dynamic and close interaction between cartilage and the developing vasculature. Vascular invasion of the primarily avascular hypertrophic chondrocyte zone brings chondroclasts, osteoblast- and endothelial precursor cells into future centres of ossification.

Vascularization of human growth plates of polydactylic digits was studied by immunohistochemistry, confocal-laser-scanning-microscopy and RT-qPCR using markers specific for endothelial cells CD34 and CD31, smooth muscle cells α-SMA, endothelial progenitor cells CD133, CXCR4, VEGFR-2 and mesenchymal progenitor cells CD90 and CD105. In addition, morphometric analysis was performed to quantify RUNX2⁺ and DLX5⁺ hypertrophic chondrocytes, RANK⁺ chondro- and osteoclasts, and CD133⁺ progenitors in different zones of the growth plate.

Results

New vessels in ossification centres were formed by sprouting of CD34⁺ endothelial cells that did not co-express the mature endothelial cell marker CD31. These immature vessels in the growth plate showed no abluminal coverage with α-SMA⁺ smooth muscle cells, but in their close proximity single CD133⁺ precursor cells were found that did not express VEGFR-2, a marker for endothelial lineage commitment. In periosteum and in the perichondrial groove of Ranvier that harboured CD90⁺/CD105⁺ chondro-progenitors, in contrast, mature vessels were found stabilized by α-SMA⁺ smooth muscle cells.

Conclusion

Vascularization of ossification centres of the growth plate was mediated by sprouting of capillaries coming from the bone collar or by intussusception rather than by de-novo vessel formation involving endothelial progenitor cells. Vascular invasion of the joint anlage was temporally delayed compared to the surrounding joint tissue.

Thrombocyte adhesion and release of extracellular microvesicles correlate with surface morphology of adsorbent polymers for lipid apheresis

Whole blood lipid apheresis is clinically applied to reduce low density lipoprotein cholesterol in patients with homozygous familial hypercholesterolemia. Here, we studied the correlation between physicochemical parameters, in particular, surface roughness and blood compatibility, of two polyacrylate-based and a dextran sulfate-based polymer for lipid apheresis. The adsorbent surface roughness was assessed by atomic force microscopy. Freshly isolated human thrombocytes were circulated over adsorbent columns downscaled equivalent to clinical use to study thrombocyte adhesion and microvesicle generation. Quantification of thrombocytes and microvesicles in the flow-through of the columns revealed that both thrombocyte adhesion and microvesicle generation increased with increasing adsorbent surface roughness. Activation of thrombocytes with thrombin receptor-activating peptide-6 favored their adhesion to the adsorbents, as demonstrated by preferential depletion of CD62(+) and PAC-1(+) thrombocytes. Taken together, enhanced polymer surface roughness fostered cell adhesion and microvesicle release, underscoring the role of extracellular microvesicles as markers of cellular activation and of blood compatibility.

Platelets increase while serum reduces the differentiation and activity of osteoclasts in vitro

Platelets modulate formation of osteoclasts and osteoblasts, but research with different preparations of platelets remains inconclusive. Here, we assessed whether serum components modulate the effect of platelet preparations. In murine bone marrow cultures, osteoclastogenesis was investigated in the presence of platelet-released supernatant (PRS), serum containing PRS (SC-PRS), and serum. Osteoclastogenesis was quantified by the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, TRAP activity and resorption assays. Also human osteoclastogenesis assays were performed. Viability and proliferation were tested by MTT and (3) [H]thymidine incorporation assays, respectively. Osteoblastogenesis was assessed by histochemical staining for alkaline phosphatase-of murine bone marrow cultures and human MG63 cells. We found PRS to increase the number of TRAP(+) multinucleated cells in the early phase and TRAP activity in the later phase of osteoclastogenesis. SC-PRS and serum decreased the number and activity of TRAP(+) multinucleated cells. Both serum containing preparations reduced viability and proliferation of hematopoietic progenitors. PRS decreased the numbers of alkaline phosphatase-positive colonies while SC-PRS and serum increased osteoblastmarkers in MG63. Proliferation of MG63 was stimulated by all preparations. These results show that activated platelets support osteoclastogenesis, while platelet preparations that contain serum components decrease osteoclastogenesis and increase osteoblastogenesis in vitro, suggesting that serum components modulate the effects of platelets on osteoclastogenesis and osteoblastogenesis.