Serum Neurotrophin Profile in Systemic Sclerosis

International audienceBACKGROUND: Neurotrophins (NTs) are able to activate lymphocytes and fibroblasts; they can modulate angiogenesis and sympathic vascular function. Thus, they can be implicated in the three pathogenic processes of systemic sclerosis (SSc). The aims of this study are to determine blood levels of Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF) and Neurotrophin-3 (NT-3) in SSc and to correlate them with clinical and biological data.METHODS: Serum samples were obtained from 55 SSc patients and 32 control subjects to measure NTs levels by ELISA and to determine their relationships with SSc profiles. FINDINGS: Serum NGF levels were higher in SSc patients (288.26 ± 170.34 pg/mL) than in control subjects (170.34 ± 50.8 pg/mL, p<0.001) and correlated with gammaglobulins levels and the presence of both anti-cardiolipin and anti-Scl-70 antibodies (p<0.05). In contrast, BDNF levels were lower in SSc patients than in controls (1121.9 ± 158.1 vs 1372.9 ± 190.9 pg/mL, p<0.0001), especially in pulmonary arterial hypertension and diffuse SSc as compared to limited forms (all p<0.05). NT-3 levels were similar in SSc and in the control group (2657.2 ± 2296 vs 2959.3 ± 2555 pg/mL, NS). BDNF levels correlated negatively with increased NGF levels in the SSc group (and not in controls). CONCLUSION: Low BDNF serum levels were not previously documented in SSc, particularly in the diffuse SSc subset and in patients with pulmonary hypertension or anti-Scl-70 antibodies. The negative correlation between NGF and BDNF levels observed in SSc and not in healthy controls could be implicated in sympathic vascular dysfunction in SSc

Biosensors fabricated by inkjet printing of functionalized mesoporous silica substrates

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Ultra sensitive biosensor based on impedance spectroscopy at microwave frequencies for cell scale analysis

International audienceThis paper presents an original approach for biological cell discrimination using impedance spectroscopy analysis at microwave frequencies. The proposed method allows label-free analysis at the cell scale using high frequency electromagnetic waves as a non-invasive probe to analyze the intracellular medium. In the present case, the biosensor design takes advantage of classical planar microwave filter topology, where coupling zones present high sensitivity to tiny dielectric perturbations. With proper design, these specific areas can be used as an electromagnetic (EM) detector. In the present work, biosensor sensitivity allows reaching selective biological sample detection and bio-impedance measurements down to single-cell analysis. As presented in this paper, this concept has been experimentally validated with characterisations conducted on biological cancerous stem cells (cells considered at a low differentiation degree) and U87 glial cells (differentiated cells); both coming from human nervous system. Stem cells are almost similar in shape and size as differentiated cells. They are therefore quite difficult to identify using a microscope, and studies focusing on their differentiation mechanisms are very challenging. Cell chemical labeling would have been suitable if we would have been sure that used label will not induce an unwanted cell differentiation. To the contrary, EM impedance measurements show a significant difference between stem and differentiated cells dielectric permittivity. Therefore, such measurements can be an efficient approach to determine cell differentiation degree in a non-invasive way. As a label-free approach, the high frequency impedance spectroscopy could be very interesting for accurate discrimination of un-differentiated cells. Indeed, stem cells are currently the subject of a large research effort in the biologist community; especially in case of cancers, where cancerous stem cells are suspected to be the origin of most of tumor recurrences. Hence, based on this identification technique, a new diagnostic analysis could be developed for early cancer recurrence prevention