Phenotypic and functional characterisation of synovial fluid-derived neutrophils in knee osteoarthritis and knee infection

OBJECTIVE

An increase in the number of neutrophils (NEUs) has long been associated with infections in the knee joints; however, their impact on knee osteoarthritis (KOA) pathophysiology remains largely unexplored.

DESIGN

This study compared the phenotypic and functional characteristics of synovial fluid (SF)-derived NEUs in KOA and knee infection (INF).

RESULTS

KOA NEUs were characterised by a lower expression of CD11b, CD54, and CD64 and higher expression of CD62L, TLR2, and TLR4 compared with INF NEUs. Except for CCL2, lower levels of inflammatory mediators and proteases were detected in KOA SF than in INF SF. Functionally, KOA NEUs displayed increased reactive oxygen species production and phagocytic activity compared with INF NEUs. Moreover, KOA and INF NEUs differed in cell sizes, histological characteristics of the surrounding synovial tissues, and their effects on the endothelial cells assessed by human umbilical vein endothelial cells. When KOA patients were subdivided based on the SF NEU abundance, patients with high NEUs (10%-60%) were characterised by i) elevated SF protein levels of TNF-α, IL-1RA, MMP-9, sTREM-1, VILIP-1 and ii) lower CD54, CD64, TLR2 and TLR4 expression compared to patients with low NEUs (<10%). Analysis of paired SF samples suggests that low or high NEU percentages, respectively, persist throughout the course of disease.

CONCLUSIONS

Our findings suggest that NEU may play a significant role in KOA pathophysiology. Further studies should explore the mechanisms that contribute to the increased number of NEUs in SF and the clinical consequences of neutrophilic phenotype in KOA.

Gender-related differences observed among immune cells in synovial fluid in knee osteoarthritis

OBJECTIVE

There is no existing comprehensive report on the cellular composition of synovial fluids (SFs) from knee osteoarthritis (OA). We therefore aimed to characterise the immune cell composition in SFs from knee OA (KOA) and in subgroups according to gender.

DESIGN

The immunophenotyping of monocyte/macrophage lineage cells, T and B cells, NK cells, neutrophils, dendritic and mast cells (MC) present in SFs from 53 patients (24 males/29 females) with KOA was performed using 6-colour flow cytometry.

RESULTS

SFs from patients with OA contained 90% hematopoietic cells. Lymphocytes were the predominant cell population (44.8%) in the SFs of OA patients, with CD4⁺ T lymphocytes being more prevalent than CD8⁺ T cells (CD4⁺/CD8⁺ ratio = 1.3). Within the monocyte/macrophage lineage gating, monocytes accounted for 33.9%, macrophages 14.8%, myeloid dendritic cells 16.4%. The rest of the hematopoietic cells were comprised of neutrophils (8%), NK cells (3.8%), T regulatory cells (1.2%), plasmacytoid dendritic cells (1.1%), mast cells (0.3%). In OA females, a higher percentage of CD4⁺ T cells (P = 0.023), macrophages (P = 0.012), and a lower percentage of monocytes (P = 0.008) and CD8⁺ T cells (P = 0.002) were detected in comparison to OA males.

CONCLUSIONS

Based on the immune cell composition of SFs, data mining analysis revealed distinct phenotypes (monocyte- and lymphocyte-predominant) within each gender group. This first study on the cellular complexity of SFs in KOA showed marked differences between male and female patients. The findings give a rational starting point for patient stratification according to their phenotypes, as is required for phenotype-specific treatment strategies.

ANTIPHOSPHOLIPID SYNDROME AND MONOCYTES: NEW ASPECTS

After discovery of antiphospholipid syndrome (APS) our understanding of molecular mechanisms of living matter has become more sophisticated and on this way monocytes has become crucial player, particularly in pathogenesis of APS. Thrombotic and non-thrombotic complications of APS could be explained by monocytes' activation too. But mechanisms underlying their activation are poorly investigated. So we aimed to determine transcriptional activity of monocytes after exposing them to low concentrations of lipopolysaccharide (LPS) and LPS+ATP using comparative of RT-PCR. Our study included eleven women suffering from recurrent miscarriages and APS (mean age 30±5,6 years). Nine healthy women (mean age of 29±8,5 years) without a positive family history of APS, autoimmune diseases and thrombosis were chosen as a control group. The results showed increasing levels of TLR2, IL-23, CCL2, CXCL10, IL-1β and IL-6 in APS cells, while in healthy cells LPS resulted in IL-6 and STAT3 elevated mRNAs. Double stimulation of APS cells resulted in decreased mRNA levels of CCL-2, IL-1β, and mRNA NLRP3 in healthy cells. At the same time TLR2 mRNAs were elevated in both groups after double stimulation. Thus increased sensitivity of APS cells to LPS may contribute to thrombus formation. Low concentration of ATP diminishes LPS-induced inflammatory state of APS monocytes, which might be one of potential regulatory mechanisms.

Transcriptional activity of neutrophils exposed to high doses of colchicine: short communication

Colchicine is an antimitotic drug which binds to tubulin and at high doses results in cytoskeleton disruption. Colchicine is believed to be an anti-inflammatory agent, though its modulatory effects on the level and transcriptional activity of genes is still a matter of debate. There is growing evidence that alterations in the cytoskeleton exert specific effects on the expression of various genes. This study was undertaken to analyze whether disrupting the microtubule cytoskeleton by colchicine modulates transcriptional levels of MEFV, NF-κB p65, NLRP3, HMGB1, and caspase-3 in neutrophils from patients with familial Mediterranean fever (FMF) and healthy subjects. In the present study, colchicine caused increased expression of NLRP3 (p=0.007) and MEFV (p=0.03), but had no effect on caspase-3, NF-κB p65 and HMGB1 genes in healthy neutrophils. FMF neutrophils were less responsive to the drug treatment. This study supports the hypothesis that, being an anti-inflammatory agent, colchicine at relatively high concentrations might lead to the activation of pro-inflammatory signalling pathways in neutrophils.

Colchicine modulates expression of pro-inflammatory genes in neutrophils from patients with familial Mediterranean fever and healthy subjects

Colchicine (Col) is a microtubule depolymerizing drug, widely used for treatment of familial Mediterranean fever (FMF). Mechanisms by which Col exerts its beneficial effects are not yet completely understood, especially with respect to gene expression in polymorphonuclear neutrophils (PMNs), the main effector cells in acute inflammatory attacks of FMF. This study was, therefore, designed to elucidate possible modulatory effect of Col on expression of inflammation-related genes in circulating PMNs from 16 FMF patients in the remission period and 11 healthy subjects. In vitro effect of Col exposure (1 microg/ml) on expression of 8 selected genes was examined using quantitative real-time RT-PCR. Col up-regulated expression of IL-8 and IL-1beta genes in FMF (13-fold and 2.7-fold, p less than 0.05, respectively) and healthy (3-fold and 6.5-fold, p less than 0.05, respectively) PMNs, and down-regulated caspase-1 in FMF neutrophils (3-fold, p less than 0.05). In FMF PMNs treated with Col mRNAs of IL-8 (51-fold, p less than 0.01) and c-FOS (7-fold, p less than 0.05) transcripts were elevated compared to those from healthy subjects. By contrast, caspase-1 mRNA was decreased in FMF neutrophils compared to healthy cells (1.6-fold, p less than 0.05). Hereby, we provide evidence that, at least in vitro, Col displays pro-inflammatory potential in respect to IL-1beta and IL-8 genes. At the same time, our findings implicate suppression of caspase-1 expression by Col as a potential mechanism for its effects in FMF treatment.

Wetting of a drop on a sphere

In this work, the equilibrium morphology of a drop on a sphere is analyzed as a function of the contact angle and drop volume experimentally and with analytical effective interfacial energy calculations. Experimentally, a drop on a sphere geometry is realized in an oil bath by placing a water drop on a sphere coated with a dielectric, of which the radii of curvature are comparable with that of the drop. Electrowetting (EW) is used to change the contact angle of the water drop on the sphere. To validate the applicability of EW and the Lippman-Young equation on nonflat surfaces, we systematically investigate the response of the contact angle to the applied voltage (EW response) for various drop volumes and compared the results with the case of a planar surface. The effective interfacial energy of two competing morphologies, namely, the spherically symmetric "completely engulfing" and "partially engulfing" morphologies are calculated analytically. The analytical calculations are then compared to the experimental results to confirm which morphology is energetically more favored for a given contact angle and drop volume. Our findings indicate that the "partially engulfing" morphology is always the energetically more favorable morphology.

Electrical switching of wetting states on superhydrophobic surfaces: a route towards reversible Cassie-to-Wenzel transitions

We demonstrate that the equilibrium shape of the composite interface between superhydrophobic surfaces and drops in the superhydrophobic Cassie state under electrowetting is determined by the balance of the Maxwell stress and the Laplace pressure. Energy barriers due to pinning of contact lines at the edges of the hydrophobic pillars control the transition from the Cassie to the Wenzel state. Barriers due to the narrow gap between adjacent pillars control the lateral propagation of the Wenzel state. We demonstrate how reversible switching between the two wetting states can be achieved locally using suitable surface and electrode geometries.

Direct observation of a nonequilibrium electro-osmotic instability

We present a visualization of the predicted instability in ionic conduction from a binary electrolyte into a charge selective solid. This instability develops when a voltage greater than critical is applied to a thin layer of copper sulfate flanked by a copper anode and a cation selective membrane. The current-voltage dependence exhibits a saturation at the limiting current. With a further increase of voltage, the current increases, marking the transition to the overlimiting conductance. This transition is mediated by the appearing vortical flow that increases with the applied voltage.

Precision in stitches: Radius Surgical System

BACKGROUND

The Radius Surgical System is a manual manipulator with two additional degrees of freedom compared with conventional laparoscopic instruments (CLIs). This study aimed to compare the performance of laparoscopic suturing tasks with the use of the Radius Surgical System and CLIs, respectively.

METHODS

Five experienced laparoscopic surgeons performed laparoscopic surgical tasks in a training box. The tasks consisted of knot-tying, suturing, and needle control tasks. The needle control task was performed to evaluate the precision of the needle drive by analysis of the needle exit point on a suture pad. In the knot-tying and suturing tasks, required time and accuracy value were measured. Needle control tasks were performed on three different angulations of plane. The angles between the instrument plane and the target plane (AIT) were 30 degrees, 60 degrees, and 90 degrees. The distance of the exit point to the center of the target field, the number of actions needed to fulfill a single task, and the required time were recorded and analyzed.

RESULTS

In the knot-tying and frontal suturing tasks, there were no significant differences between the two groups. In the sagittal suturing task, the required time in the Radius group was significantly shorter than in the CLI group. In the needle control tasks on 30 degree and 60 degree AIT, the distance was significantly shorter in the Radius group than in the CLI group. There were no significant differences in the number of actions or the required time. In the frontal and sagittal needle control task on 90 degree AIT, the distance was significantly shorter in the Radius group than in the CLI group. The number of actions and the required time were significantly less in the Radius group than in the CLI group.

CONCLUSIONS

The two additional degrees of freedom contributed to accurate and controlled needle guidance, especially in difficult spatial situations.