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Measuring Deformability and Red Cell Heterogeneity in Blood by Ektacytometry.
J Vis Exp. 2018 01 12JV

Abstract

Decreased red cell deformability is characteristic of several disorders. In some cases, the extent of defective deformability can predict severity of disease or occurrence of serious complications. Ektacytometry uses laser diffraction viscometry to measure the deformability of red blood cells subject to either increasing shear stress or an osmotic gradient at a constant value of applied shear stress. However, direct deformability measurements are difficult to interpret when measuring heterogenous blood that is characterized by the presence of both rigid and deformable red cells. This is due to the inability of rigid cells to properly align in response to shear stress and results in a distorted diffraction pattern marked by an exaggerated decrease in apparent deformability. Measurement of the degree of distortion provides an indicator of the heterogeneity of the erythrocytes in blood. In sickle cell anemia, this is correlated with the percentage of rigid cells, which reflects the hemoglobin concentration and hemoglobin composition of the erythrocytes. In addition to measuring deformability, osmotic gradient ektacytometry provides information about the osmotic fragility and hydration status of erythrocytes. These parameters also reflect the hemoglobin composition of red blood cells from sickle cell patients. Ektacytometry measures deformability in populations of red cells and does not, therefore, provide information on the deformability or mechanical properties of individual erythrocytes. Regardless, the goal of the techniques described herein is to provide a convenient and reliable method for measuring the deformability and cellular heterogeneity of blood. These techniques may be useful for monitoring temporal changes, as well as disease progression and response to therapeutic intervention in several disorders. Sickle cell anemia is one well-characterized example. Other potential disorders where measurements of red cell deformability and/or heterogeneity are of interest include blood storage, diabetes, Plasmodium infection, iron deficiency, and the hemolytic anemias due to membrane defects.

Authors+Show Affiliations

Department of Pediatrics, Saint Louis University School of Medicine; nermi.parrow@nih.gov.Molecular and Clinical Nutrition Section, Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases.Molecular and Clinical Nutrition Section, Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases.Molecular and Clinical Hematology Branch, National Institute of Diabetes and Digestive and Kidney Diseases.Sickle Cell Branch, National Heart, Lung and Blood Institute, National Institutes of Health.Sickle Cell Branch, National Heart, Lung and Blood Institute, National Institutes of Health.Department of Pediatrics, Saint Louis University School of Medicine; Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine.Red Cell Physiology Laboratory, New York Blood Center.Molecular and Clinical Hematology Branch, National Institute of Diabetes and Digestive and Kidney Diseases.Molecular and Clinical Nutrition Section, Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases.

Pub Type(s)

Journal Article
Research Support, N.I.H., Intramural
Video-Audio Media

Language

eng

PubMed ID

29364234

Citation

Parrow, Nermi L., et al. "Measuring Deformability and Red Cell Heterogeneity in Blood By Ektacytometry." Journal of Visualized Experiments : JoVE, 2018.
Parrow NL, Violet PC, Tu H, et al. Measuring Deformability and Red Cell Heterogeneity in Blood by Ektacytometry. J Vis Exp. 2018.
Parrow, N. L., Violet, P. C., Tu, H., Nichols, J., Pittman, C. A., Fitzhugh, C., Fleming, R. E., Mohandas, N., Tisdale, J. F., & Levine, M. (2018). Measuring Deformability and Red Cell Heterogeneity in Blood by Ektacytometry. Journal of Visualized Experiments : JoVE, (131). https://doi.org/10.3791/56910
Parrow NL, et al. Measuring Deformability and Red Cell Heterogeneity in Blood By Ektacytometry. J Vis Exp. 2018 01 12;(131) PubMed PMID: 29364234.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Measuring Deformability and Red Cell Heterogeneity in Blood by Ektacytometry. AU - Parrow,Nermi L, AU - Violet,Pierre-Christian, AU - Tu,Hongbin, AU - Nichols,James, AU - Pittman,Corinne A, AU - Fitzhugh,Courtney, AU - Fleming,Robert E, AU - Mohandas,Narla, AU - Tisdale,John F, AU - Levine,Mark, Y1 - 2018/01/12/ PY - 2018/1/25/entrez PY - 2018/1/25/pubmed PY - 2018/6/21/medline JF - Journal of visualized experiments : JoVE JO - J Vis Exp IS - 131 N2 - Decreased red cell deformability is characteristic of several disorders. In some cases, the extent of defective deformability can predict severity of disease or occurrence of serious complications. Ektacytometry uses laser diffraction viscometry to measure the deformability of red blood cells subject to either increasing shear stress or an osmotic gradient at a constant value of applied shear stress. However, direct deformability measurements are difficult to interpret when measuring heterogenous blood that is characterized by the presence of both rigid and deformable red cells. This is due to the inability of rigid cells to properly align in response to shear stress and results in a distorted diffraction pattern marked by an exaggerated decrease in apparent deformability. Measurement of the degree of distortion provides an indicator of the heterogeneity of the erythrocytes in blood. In sickle cell anemia, this is correlated with the percentage of rigid cells, which reflects the hemoglobin concentration and hemoglobin composition of the erythrocytes. In addition to measuring deformability, osmotic gradient ektacytometry provides information about the osmotic fragility and hydration status of erythrocytes. These parameters also reflect the hemoglobin composition of red blood cells from sickle cell patients. Ektacytometry measures deformability in populations of red cells and does not, therefore, provide information on the deformability or mechanical properties of individual erythrocytes. Regardless, the goal of the techniques described herein is to provide a convenient and reliable method for measuring the deformability and cellular heterogeneity of blood. These techniques may be useful for monitoring temporal changes, as well as disease progression and response to therapeutic intervention in several disorders. Sickle cell anemia is one well-characterized example. Other potential disorders where measurements of red cell deformability and/or heterogeneity are of interest include blood storage, diabetes, Plasmodium infection, iron deficiency, and the hemolytic anemias due to membrane defects. SN - 1940-087X UR - https://www.unboundmedicine.com/medline/citation/29364234/Measuring_Deformability_and_Red_Cell_Heterogeneity_in_Blood_by_Ektacytometry_ DB - PRIME DP - Unbound Medicine ER -