Impaired Hemorheology in Exacerbations of COPD

Background. Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation. Cardiovascular-related comorbidities are established to contribute to morbidity and mortality especially during exacerbations. The aim of the current study was to determine alterations in hemorheology (erythrocyte aggregation, deformability) in newly diagnosed COPD patients and their response to medical treatment and to compare with values of COPD patients with exacerbations. Materials and Methods. The study comprised 13 COPD patients, 12 controls, and 16 COPD patients with exacerbations. The severity of COPD was determined according to Global Initiative for Chronic Obstructive Lung Disease guidelines. Red blood cell (RBC) deformability and aggregation were measured by an ektacytometer. Results. RBC deformability of COPD patients with exacerbations was decreased compared to the other groups. Erythrocyte aggregation and plasma fibrinogen of COPD patients determined during exacerbations were higher than control. Conclusion. Decreased RBC deformability and increased aggregation associated with exacerbations of COPD may serve as unfavorable mechanisms to worsen oxygenation and thus clinical symptoms of the patient. Treatment modalities that modify rheological parameters might be beneficial. © 2017 Erhan Ugurlu et al

Modulation of density-fractionated RBC deformability by nitric oxide

The role of nitric oxide (NO) in maintaining normal mechanical behavior of red blood cell (RBC) has been previously demonstrated. The effects of NO donor and NOS inhibitor on the mechanical properties of density fractionated RBC were tested in this study. A non-specific NOS inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME) at a concentration of 10-3 M and sodium nitroprusside (SNP), a nitric oxide donor at a concentration of 10-6 M was added to blood samples with hematocrit adjusted to 0.4 l/l and RBC deformability was measured by an ektacytometer in the density fractionated RBC after one hour incubation at 37°C. There was no significant effect of the NO donor SNP on cellular deformability in the older (denser) RBC fraction in contrast with the younger (least dense) fraction. Alternatively, the sensitivity of cellular deformability to competitive NOS inhibition by L-NAME was greater in the older fraction. These findings suggest that older RBC are characterized by diminished internal NO synthesis and are also less sensitive to external NO indicating that the target mechanisms for NO may also be deteriorated. © 2005 - IOS Press and the authors. All rights reserved

Effect of penicillin G-induced epileptic seizures on hemorheological parameters in rats

Normally, cerebral blood flow (CBF) is quantitatively coupled to cerebral metabolic rate like other tissues and maintained basically by altering vascular geometry and appropriate perfusion pressure. However, the rheological properties of the blood are important factors for effective tissue perfusion. Although a lot of studies have reported that hemorheological parameters are affected by a wide range of pathophysiological conditions, to our knowledge no research related to the effects of epileptic seizures on hemorheological parameters has been carried out. Thus, the aim of this study was to explore possible changes in rheological parameters including red blood cell (RBC) deformability, rigidity and aggregation, whole blood and plasma viscosity during epileptic seizures induced by penicillin G in rats. Eighteen female albino rats were divided into three groups that included sham operated controls (Group S), epileptic group (Group E), intraperitoneal penicillin group (Group IPP). Epilepsy was induced by intracortical injections of penicillin G. Hemorheological studies had been carried out 3 h after the induction of epilepsy. Among the studied hemorheological parameters, only RBC deformability was found to be different in the E group compared to S group. Epileptic seizures led to an increase in RBC deformability in the E group. In conclusion, these results suggest that in addition to an increase in CBF, RBC deformability may also improve to better match brain metabolic demands during seizures. © 2006 Elsevier Inc. All rights reserved