In vitro and ex vivo effect of hyaluronic acid on erythrocyte flow properties

<p>Abstract</p> <p>Background</p> <p>Hyaluronic acid (HA) is present in many tissues; its presence in serum may be related to certain inflammatory conditions, tissue damage, sepsis, liver malfunction and some malignancies. In the present work, our goal was to investigate the significance of hyaluronic acid effect on erythrocyte flow properties. Therefore we performed <it>in vitro </it>experiments incubating red blood cells (RBCs) with several HA concentrations. Afterwards, in order to corroborate the pathophysiological significance of the results obtained, we replicated the <it>in vitro </it>experiment with <it>ex vivo </it>RBCs from diagnosed rheumatoid arthritis (RA) patients, a serum HA-increasing pathology.</p> <p>Methods</p> <p>Erythrocyte deformability (by filtration through nucleopore membranes) and erythrocyte aggregability (EA) were tested on blood from healthy donors additioned with purified HA. EA was measured by transmitted light and analyzed with a mathematical model yielding two parameters, the aggregation rate and the size of the aggregates. Conformational changes of cytoskeleton proteins were estimated by electron paramagnetic resonance spectroscopy (EPR).</p> <p>Results</p> <p><it>In vitro</it>, erythrocytes treated with HA showed increased rigidity index (RI) and reduced aggregability, situation strongly related to the rigidization of the membrane cytoskeleton triggered by HA, as shown by EPR results. Also, a significant correlation (r: 0.77, p < 0.00001) was found between RI and serum HA in RA patients.</p> <p>Conclusions</p> <p>Our results lead us to postulate the hypothesis that HA interacts with the erythrocyte surface leading to modifications in erythrocyte rheological and flow properties, both <it>ex vivo </it>and <it>in vitro</it>.</p

Erythrocyte aggregation in rheumatoid arthritis: cell and plasma factor’s role

ncrease in erythrocyte aggregation (EA) is pathognomonic for rheumatoid arthritis (RA), and its estimation through erythrocyte sedimentation rate (ESR) is part of DAS 28-4 activity diagnosis, with low correlation with EA and that does not discriminate the contribution of cell factors that increase aggregation. Objective: To analyse cell and plasma factors that might be involved in EA increase, to understand how RA affects blood components, thus modifying blood fluid behavior. Methodology: One hundred women presenting active RA were compared with age-matched controls (C). EA was measured by transmitted light, obtaining two parameters: 2k2n0, characterizing the aggregation process kinetics and s0/n0, estimating aggregates size. Cell factors assays: erythrocyte deformability, by filtration through nucleopore membranes, cell shape, by microscopy, and membrane fluidity by EPR. Plasma: total proteins and CRP, albumin, fibrinogen (Fb), by gravimetry, and IgG and IgM by single radial immuno-diffusion. Results: AR and C (x ± SE). 2k2n0: 31.83 ± 2.84, 23.75 ± 1.91; s0/n0: 0.92 ± 0.05, 0.87 ± 0.04. Rigidity index (RI): 14.79 ± 4.71, 6.92 ± 1.31. Morphological index: 0.28 ± 0.03, 0.30 ± 0.05, n.s. Fb (mg/dl): 382 ± 80, 299 ± 70. IgG (mg/dl): 1580 ± 219, 1296 ± 158; IgM (mg/dl) 233 ± 28, 183 ± 23; albumin (g/dl) 3.84 ± 0.44, 3.77 ± 0.51 n.s. p < 0.05 accepted. Correlations: 2k2n0 vs. Fb r = 0.66; s0/n0 vs. Fb r = 0.51; 2k2n0 vs. Igs r = 0.65; s0/n0 vs. Igs r = 0.56. 2k2n0 vs. RI r = -0.59; s0/n0 vs. RI = -0.52, p < 0.05. Conclusions: Plasma factors, Igs and Fb increased aggregation, since RI is altered, this reduces the process efficiency regarding aggregation. Patients with active RA present an increased EA, with values modifications associated with the activity index DAS 28-4, thus becoming an RA activity indicator.Fil: Luquita, A.. Universidad Nacional de Rosario; ArgentinaFil: Urli, L.. Universidad Nacional de Rosario; ArgentinaFil: Svetaz, M. J.. Universidad Nacional de Rosario; ArgentinaFil: Gennaro, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Volpintesta, R.. Universidad Nacional de Rosario; ArgentinaFil: Palatnik, S.. Universidad Nacional de Rosario; ArgentinaFil: Rasia, M.. Universidad Nacional de Rosario; Argentin

Haemorheological variables as a rheumatoid arthritis activity indicator

Objective: To investigate if blood hyperviscosity in RA patients is due to a reduced erythrocyte deformability and, therefore, turning it into a reliable activity indicator, as well as a therapy follow-up marker for this pathology. Methods: (1) The haemorheological profile consisting of erythrocyte deformability, blood and plasma viscosity, and erythrocyte membrane fluidity was determined in 24 AR patients and 17 healthy controls. (2) A 4 year follow-up was carried on in 16 patients monitoring blood viscosity, erythrocyte deformability and biochemical variables in relation to clinical assessment of disease activity (Disease Activity Score “DAS 28-4”). Results: Erythrocyte deformability and membrane fluidity were impaired in RA patients compared to controls (p<0.001). Blood viscosity was significantly increased and correlated with the cell rigidity index (r=0.85, p<0.0000) in RA patients. The follow-up showed a good correlation between haemorheological parameters and DAS 28-4 during disease evolution. Conclusion: our results support the hypothesis that in RA, blood hyperviscosity is determined by deformability loss, which in turn is due to a membrane rigidization. This could evidenced that a widespread cell membrane damage is expressed through an impaired erythrocyte deformability, turning haemorheological parameters into reliable tools to study disease evolution. The follow-up study enabled us to confirm that erythrocyte deformability is an efficient indicator of rheumatoid arthritis activity.Fil: Luquita, A.. Universidad Nacional de Rosario; ArgentinaFil: Urli, L.. Universidad Nacional de Rosario; ArgentinaFil: Dominighini, A.. Universidad Nacional de Rosario; ArgentinaFil: Svetaz, M. J.. Universidad Nacional de Rosario; ArgentinaFil: Gennaro, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Volpintesta, R.. Universidad Nacional de Rosario; ArgentinaFil: Palatnik, S.. Universidad Nacional de Rosario; ArgentinaFil: Rasia, M.. Universidad Nacional de Rosario; Argentin

Phase I-II trial of gemcitabine-based first-line chemotherapies for small cell lung cancer in elderly patients with performance status 0-2: The G-Step trial

Introduction: Treatment of elderly patients with small cell lung cancer (SCLC) is based on scanty evidence. Methods: Patients with extensive SCLC, age &gt;70 years, and performance status 0-2 were eligible for a study looking for optimal two-drug combination of gemcitabine (Gem) with vinorelbine (Vin), etoposide (Eto), cisplatin (Cis), or carboplatin (Car). Gemcitabine dose was the same (1000 mg/m2, days 1-8) in all combinations. A two-stage minimax flexible design for response was applied to GemVin combination (Vin 25 mg/m2, days 1-8). For GemCar, GemCis, GemEto, a phase I-II Bayesian design was applied, looking for the optimal dose of the partner drugs. Objective response rate ≥60% and unacceptable toxicity ≤25% were required to define a combination worthy of further studies. Results: Median age of 78 eligible patients was 74 years. GemVin produced a 36.7% objective response rate. GemEto and GemCis arms were found not sufficiently active. GemCar produced 16 responses (14 with area under the curve [AUC] 3.5 and 2 with AUC 4.0) in 26 patients (61.5%) and 6 cases of unacceptable toxicity (3 at each Car dose). Conclusions: In elderly patients with extensive SCLC, GemVin, GemEto, and GemCis are not enough active and do not merit further studies. Gem plus Car might deserve further attention. © 2011 by the International Association for the Study of Lung Cancer