Hemolytic properties of synthetic nano- and porous silica particles: the effect of surface properties and the protection by the plasma corona

Novel silica materials incorporating nanotechnology are promising materials for biomedical applications, but their novel properties may also bring unforeseen behavior in biological systems. Micro-size silica is well documented to induce hemolysis, but little is known about the hemolytic activities of nanostructured silica materials. In this study, the hemolytic properties of synthetic amorphous silica nanoparticles with primary sizes of 7-14 nm (hydrophilic vs. hydrophobic), 5-15 nm, 20 nm and 50 nm, and model meso/macroporous silica particles with pore diameters of 40 nm and 170 nm are investigated. A crystalline silica sample (0.5-10 μm) is included for benchmarking purposes. Special emphasis is given to investigations of how the temperature and solution complexity (solvent, plasma), as well as the physicochemical properties (such as size, surface charge, hydrophobicity and other surface properties), link to the hemolytic activities of these particles. Results suggests the potential importance of small size and large external surface area, as well as surface charge/structure, in the hemolysis of silica particles. Furthermore, a significant correlation is observed between the hemolytic profile of red blood cells and the cytotoxicity profile of human promyelocytic leukemia cells (HL-60) induced by nano- and porous silica particles, suggesting a potential universal mechanism of action. Importantly, the results generated suggest that the protective effect of plasma towards silica nanoparticle-induced hemolysis as well as cytotoxicity is primarily due to the protein/lipid layer shielding the silica particle surface. These results will assist the rational design of hemocompatible silica particles for biomedical applications.     

Treatment of inflammatory bowel disease by chemokine receptor-targeted leukapheresis

Leukapheresis removes circulating leukocytes en route to the target organ. Hitherto unspecific matrixes have been used to remove leukocytes in inflammatory bowel disease (IBD). This report describes a novel selective leukapheresis column based on chemokine–chemokine receptor interaction. We found an increased expression of the gut homing chemokine receptor CCR9 on CD14⁺ monocytes and on CD3⁺ T lymphocytes from IBD patients. Biologically active CCL25 was coupled to a Sepharose matrix and demonstrated to selectively remove CCR9-expressing cells leaving other cell populations largely unaffected. A patient with active ulcerative colitis, was subjected to CCL25-column leukapheresis. Four days after treatment, he experienced clinical improvement and stable disease improvement ensued. The study illustrates that specific cells can be targeted using high affinity interactions, i.e., CCL25–CCR9 interactions to remove pathogenic gut-homing cells. Leukapheresis using the bCCL25 column should be investigated in a clinical phase I trial of patients with inflammatory bowel disease.     

A Genome‐Wide Assessment of Variability in Human Serum Metabolism

The study of the genetic regulation of metabolism in human serum samples can contribute to a better understanding of the intermediate biological steps that lead from polymorphism to disease. Here, we conducted a genome‐wide association study (GWAS) to discover metabolic quantitative trait loci (mQTLs) utilizing samples from a study of prostate cancer in Swedish men, consisting of 402 individuals (214 cases and 188 controls) in a discovery set and 489 case‐only samples in a replication set. A global nontargeted metabolite profiling approach was utilized resulting in the detection of 6,138 molecular features followed by targeted identification of associated metabolites. Seven replicating loci were identified (PYROXD2, FADS1, PON1, CYP4F2, UGT1A8, ACADL, and LIPC) with associated sequence variants contributing significantly to trait variance for one or more metabolites (P = 10^?13–10^?91). Regional mQTL enrichment analyses implicated two loci that included FADS1 and a novel locus near PDGFC. Biological pathway analysis implicated ACADM, ACADS, ACAD8, ACAD10, ACAD11, and ACOXL, reflecting significant enrichment of genes with acyl‐CoA dehydrogenase activity. mQTL SNPs and mQTL‐harboring genes were over‐represented across GWASs conducted to date, suggesting that these data may have utility in tracing the molecular basis of some complex disease associations.     

No protective role for hypoxic pulmonary vasoconstriction in severe hypergravity-induced arterial hypoxemia

Supine subjects exposed to hypergravity show a marked arterial desaturation. Previous work from our laboratory has also shown a paradoxical reduction of lung perfusion in dependent lung regions in supine subjects exposed to hypergravity. We reasoned that the increased lung weight during hypergravity caused either direct compression of the blood vessels in the dependent lung tissue or that poor regional ventilation caused reduced perfusion through hypoxic pulmonary vasoconstriction (HPV). The objective of this study was to evaluate the importance of HPV through measurements of arterial oxygenation during exposure to hypergravity with normal and attenuated HPV. A further increased arterial desaturation during hypergravity with attenuated HPV would support the hypothesis that HPV contributes to the paradoxical redistribution of regional perfusion. In a two-phased randomized study we first exposed 12 healthy subjects to 5 G while supine during two single-blinded conditions; control and after 50 mg sildenafil p.o.. In a second phase, 12 supine subjects were exposed to 5 G during three single-blinded conditions; control, after 100 mg sildenafil p.o. and after inhalation of 10 μg iloprost. There was a substantial arterial desaturation by 5–30% units in all subjects with no or only minor differences between conditions. The results speak against HPV as a principal mechanism for the hypergravity-induced reduction of lung perfusion in dependent lung regions in supine humans.     

Invariant natural killer T cells balance B cell immunity

Invariant natural killer T (iNKT) cells mediate rapid immune responses which bridge the gap between innate and adaptive responses to pathogens while also providing key regulation to maintain immune homeostasis. Both types of important iNKT immune responses are mediated through interactions with innate and adaptive B cells. As such, iNKT cells sit at the decision‐making fulcrum between regulating inflammatory or autoreactive B cells and supporting protective or regulatory B cell populations. iNKT cells interpret the signals in their environment to set the tone for subsequent adaptive responses, with outcomes ranging from getting licensed to maintain homeostasis as an iNKT regulatory cell (iNKT_reg) or being activated to become an iNKT follicular helper (iNKT_FH) cell supporting pathogen‐specific effector B cells. Here we review iNKT and B cell cooperation across the spectrum of immune outcomes, including during allergy and autoimmune disease, tumor surveillance and immunotherapy, or pathogen defense and vaccine responses. Because of their key role as influencers, iNKT cells provide a valuable target for therapeutic interventions. Understanding the nature of the interactions between iNKT and B cells will enable the development of clinical interventions to strategically target regulatory iNKT and B cell populations or inflammatory ones, depending on the circumstance.     

BCOR internal tandem duplication and YWHAE–NUTM2B/E fusion are mutually exclusive events in clear cell sarcoma of the kidney

Clear cell sarcoma of the kidney (CCSK) is the second most common pediatric renal tumor. Two recurrent genetic aberrations have been described in CCSK. One is a fusion of YWHAE and NUTM2B/E, the other is an internal tandem duplication (ITD) in the BCOR gene. Here it is shown that YWHAE–NUTM2B/E fusion and the BCOR ITD are mutually exclusive events and activated different downstream signaling systems. This has important diagnostic implications and opens up for further mechanistic studies of CCSK pathogenesis. © 2015 Wiley Periodicals, Inc.     

The presence of stomatin in detergent-insoluble domains of neutrophil granule membranes

Neutrophil azurophil granules, traditionally regarded as the neutrophil counterpart to lysosomes, lack the lysosomal marker lysosome-associated membrane glycoprotein and have recently been suggested to be nonlysosomal secretory organelles. The membrane of the azurophil granules is poorly characterized-CD63 and CD68 are the only membrane proteins identified so far. Here, azurophil granule membranes were isolated by Percoll gradient subcellular fractionation. Using matrix-assisted laser desorption ionization time of flight mass spectrometry of tryptic peptides from an isolated protein, stomatin was identified in these membranes. Using immunoelectron microscopy and immunoblot analysis of isolated organelles, stomatin was found to be subcellularly localized, not only to the azurophil granules but also by a major part to the specific granules and by a minor part to the secretory vesicles/plasma membrane. We also show the presence of detergent-insoluble, low-density membrane domains in the plasma membrane and the granule membranes and found stomatin to be localized to these domains.     

Glutamate-induced currents reveal three functionally distinct NMDA receptor populations in rat dorsal horn - effects of peripheral nerve lesion and inflammation

The importance of the N-methyl-D-aspartate (NMDA) receptor in various painful conditions is well established. The effects of peripheral nerve lesion or joint inflammation, as models of different pain states, on NMDA receptor-mediated currents and NMDA receptor subunit mRNA expression were therefore studied in acutely dissociated neurones from the rat spinal cord dorsal horn. In the neuronal population from control rats, all four NR2 subunits and both NR1 splice variants assayed were detected. A majority of neurones expressed mRNA for more than one NR2 subunit, and some neurones expressed all four NR2 subunits as well as both NR1 splice variants. The NR2B subunit was the most commonly expressed, while the NR2C was the rarest. Following nerve lesion, fewer neurones expressed NR2A compared to the control. The dose-response curve for glutamate-evoked NMDA receptor-mediated currents in the neurones was best described by a three-component fit, suggesting that three functionally distinct NMDA receptor populations are present in the dorsal horn. Minor changes in the dose-response curve after nerve lesion could not be ascribed with certainty to the lesion. Changes in other parameters of NMDA receptor-mediated currents were observed neither after nerve lesion nor after joint inflammation.In summary, the present work demonstrates that single dorsal horn neurones express mRNA for several NMDA receptor subunits. The glutamate dose-response curves indicate that there are three major types of NMDA receptors present in dorsal horn neurones. We also report a reduced expression of NR2A following peripheral nerve lesion.     

Myocardial perfusion monitoring during coronary artery bypass using an electrocardiogram-triggered laser Doppler technique

Electrocardiogram (ECG)—triggered laser Doppler perfusion monitoring (LDPM) was used to assess myocardial perfusion, with minimum myocardial tissue motion influence, during coronary artery bypass grafting (CABG). Thirteen subjects were investigated at six phases: pre- and post-CABG; post aorta cross-clamping; pre and post left internal mammary artery (LIMA) graft declamping; and post aorta declamping. The perfusion signal was calculated in late systole and late diastole, with expected minimum tissue motion, and compared with arrested heart measurements. Patient conditions or artifacts caused by surgical activity made it impossible to perform and analyse data in all six phases for some patients. No significant (n=5) difference between perfusion signals pre- and post-CABG was found. Diastolic perfusion signal levels were significantly (p<0.02) lower compared with systolic levels. After aorta cross-clamping, the signal level was almost zero. A distinct perfusion signal increase after LIMA and aorta declamping, compared with pre-LIMA declamping, was found in ten cases out of 13. A significantly (p<0.04) lower perfusion signal in the arrested heart compared with in the beating heart was registered. Influence from mechanical ventilation was observed in 14 measurements out of 17. In conclusion, ECG-triggered LDPM can be used to assess myocardial perfusion during CABG. Perfusion signals were lower in the arrested heart compared with in the beating heart and in late diastole compared with late systole. No significant difference between pre- and post-CABG was found.