Seroprevalence of Toxoplasma gondii infection in arthritis patients in eastern China

Background: There is accumulating evidence for an increased susceptibility to infection in patients with arthritis. We sought to understand the epidemiology of Toxoplasma gondii infection in arthritis patients in eastern China, given the paucity of data on the magnitude of T. gondii infection in these patients. Methods: Seroprevalence of T. gondii infection was assessed by enzyme-linked immunosorbent assay using a crude antigen of the parasite in 820 arthritic patients, and an equal number of healthy controls, from Qingdao and Weihai cities, eastern China. Sociodemographic, clinical and lifestyle information on the study participants were also obtained. Results: The prevalence of anti-T. gondii IgG was significantly higher in arthritic patients (18.8%) compared with 12% in healthy controls (P < 0.001). Twelve patients with arthritis had anti-T. gondii IgM antibodies comparable with 10 control patients (1.5% vs 1.2%). Demographic factors did not significantly influence these seroprevalence frequencies. The highest T. gondii infection seropositivity rate was detected in patients with rheumatoid arthritis (24.8%), followed by reactive arthritis (23.8%), osteoarthritis (19%), infectious arthritis (18.4%) and gouty arthritis (14.8%). Seroprevalence rates of rheumatoid arthritis and reactive arthritis were significantly higher when compared with controls (P < 0.001 and P = 0.002, respectively). A significant association was detected between T. gondii infection and cats being present in the home in arthritic patients (odds ratio [OR], 1.68; 95% confidence interval [CI]: 1.24 – 2.28; P = 0.001). Conclusions: These findings are consistent with and extend previous results, providing further evidence to support a link between contact with cats and an increased risk of T. gondii infection. Our study is also the first to confirm an association between T. gondii infection and arthritis patients in China. Implications for better prevention and control of T. gondii infection in arthritis patients are discussed. Trial registration: This is an epidemiological survey, therefore trial registration was not required

Investigating NF-kappa B signaling in lung fibroblasts in 2D and 3D culture systems

BACKGROUND: Inflammatory respiratory diseases are amongst major global health challenges. Lung fibroblasts have been shown to play a key role in lung inflammatory responses. However, their exact role in initiation and maintenance of lung diseases has remained elusive partly due to the limited availability of physiologically relevant in vitro models. Therefore, developing new tools that enable investigating the molecular pathways (e.g. nuclear factor-kappa B (NF-κB) activation) that underpin inflammatory responses in fibroblasts could be a valuable resource for scientists working in this area of research. RESULTS: In order to investigate NF-κB activation in response to pro-inflammatory stimuli in real-time, we first developed two detection systems based on nuclear localization of NF-κB by immunostaining and luciferase reporter assay system. Furthermore using electrospun porous scaffolds, with similar geometry to human lung extracellular matrix, we developed 3D cultures of lung fibroblasts allowing comparing NF-κB activation in response to pro-inflammatory stimuli (i.e. TNF-α) in 2D and 3D. Our data clearly show that the magnitude of NF-κB activation in 2D cultures is substantially higher than 3D cultures. However, unlike 2D cultures, cells in the 3D model remained responsive to TNF-α at higher concentrations. The more subdued and wider dynamic range of NF-κB responses in 3D culture system was associated with a different expression pattern for TNF receptor I in 3D versus 2D cultures collectively reflecting a more in vivo like TNF receptor I expression and NF-κB activation pattern in the 3D system. CONCLUSION: Our data suggest that lung fibroblasts are actively involved in the pathogenesis of lung inflammation by activation of NF-κB signaling pathway. The 3D culture detection system provides a sensitive and biologically relevant tool for investigating different pro-inflammatory events involving lung fibroblasts

Electronic sorting and recovery of single live cells from microlitre sized samples

International audienceSorting and recovering specific live cells from samples containing less than a few thousand cells have become major hurdles in rare cell exploration such as stem cell research, cell therapy and cell based diagnostics. We describe here a new technology based on a microelectronic chip integrating an array of over 100,000 independent electrodes and sensors which allow individual and parallel single cell manipulation of up to 10,000 cells while maintaining viability and proliferation capabilities. Manipulation is carried out using dynamic dielectrophoretic traps controlled by an electronic interface. We also demonstrate the capabilities of the chip by sorting and recovering individual live fluorescent cells from an unlabeled population

Non-linearity in lipase assays: A multicentric comparison on different analysers

OBJECTIVES: Non-linearity in lipase assays and the ensuing gaps in results distribution have been described on Roche analysers, but have yet to be studied on other analysers. DESIGN AND METHODS: Eighteen lithium-heparinized plasma pools of lipase activities decreasing from 1700 to \textless4 U/L were prepared for multicentric evaluation on several analysers. Non-linearity was modelled as the difference between the polynomial regression of lipase activities depending on relative dilutions over the primary measuring range, and the linear regression of the same variables above the manufacturer's limit of linearity (MLL). Gaps in lipase distribution resulting from non-linearity were graphically evidenced through histograms. Upper limits of gaps were calculated, which are lipase activities where non-linearity biases no longer impact the diluted lipase results. RESULTS: MLLs and lipase (U/L) calculated at MLL (%biases versus MLL) were respectively: 1200 and 1124 (-6.3%) on the Architect C16000 (Abbott); 300 and 248 (-17.3%) on the Cobas c503 (Roche); 1500 and 1458 (-2.8%) on the Dimension Vista (Siemens); and 700 and 659 (-5.9%) on the Atellica CH930 (Siemens). Using Sentinel Lipase reagents on Abbott analysers, these measurements were respectively: 300 and 294 (-2.0%) on the Architect C16000, and 300 and 298 (-0.7%) on the Alinity. Setting Randox Lipase reagents on the Alinity, MLL and lipase at MLL were 953 and 776 (-18.6%), respectively. CONCLUSIONS: Considering the desirable (±14.2 %) and optimal (±7.1 %) allowable total error for lipase (EFLM/EuBIVAS), biases at manufacturer's limit of linearity were acceptable, except for Roche Cobas c503 method and Randox method on Abbott Alinity

Toxoplasma gondii infection can regulate the expression of tumour necorsis factor-alpha receptors on human cell in vitro

International audienceThe in vitro regulation of tumour necrosis factor (TNF)-α receptors during Toxoplasma gondii infection of human MRC5 fibroblasts and human myelomonocytic THP-1 cells was investigated. Cells were infected with the virulent RH of T. gondii. TNFR membrane receptors were analysed by flow cytometry with biotinylated TNF-α. Shedding of the soluble form of TNFR1 and TNFR2 in cell culture supernatants was measured by enzyme-linked immunosorbent assay, and expression of mRNA production of TNFR1 and TNFR2 was analysed by quantitative real-time ploymerase chain reaction, 1 h after infection. In the MRC5 cell line, T. gondii infection did not induce any up- or down-regulation of membrane TNFRs, soluble TNFRs or mRNA of TNFRs. However, THP-1 cell infection with living parasites induced a significant soluble TNFR1 release by THP-1 cells after 1 h. We detected an approximately 50% up-regulation (P < 0·01) of soluble TNFR1 in infected THP-1 cells compared to controls. No change in soluble TNFR2 levels was observed in the same conditions. Moreover, infection decreased the level of TNF membrane receptors, but had no effect on TNFR1 and TNFR2 mRNA levels. TNFR modulation by T. gondii infection, in vitro, depends on the cell type. Furthermore, our data suggest that living parasites control the shedding of the soluble form of TNFR1. This mechanism may influence the role of TNF-α in toxoplasmosis