Research

The RBC membrane consists of a lipid bilayer with a cytoskeleton underneath. Among the important function of the membrane components is deformability and mechanical stability [1]. Inherited red blood cell (RBC) membrane disorders, such as hereditary spherocytosis, elliptocytosis and hereditary ovalocytosis, result from mutations in genes encoding various RBC membrane and skeletal proteins [2]. These diseases mainly lead to reduced RBC deformability, shortened RBC lifespan, splenomegaly, and hemolytic anemia.

The Lorrca instrument has a dedicated test to assess automatically measure RBC deformability over a gradient of osmotic values. This results in a continuous curve; an Osmoscan test shows the cell’s condition at the different osmotic values. The test provides information about the cell’s deformability and membrane rigidity, depending on both the shape and the position along the osmolality axis. Furthermore, the Lorrca harbors the deformability test, RBCs suspended in Elon-ISO are sheared between two concentric cylinders, the cup, and the bob. A known shear stress is applied to the cells, resulting in the deformation of the RBCs, expressed on the y-axis as Elongation Index (EI) as a function of the shear stress. In the aggregation measurement, a complete disaggregation of the RBC’s is induced by applying a high shear rate; followed by an abrupt stop, which causes the elongated RBC to retake their normal shape. Then the aggregation process starts, at which rouleaux formation occurs. A syllectogram is created by plotting the backscattered laser intensity versus time.

The Lorrca Osmoscan based on ektacytometry helps to expand our realms in this field. The red cell enzymes allow erythrocytes to meet the tasks such as energy production and protection from oxidative stress by supporting the glycolytic and pentose pathways. The hereditary enzyme deficiencies of these pathways can cause diverse effects such as anemia, polycythemia, methemoglobinemia [1,2].

Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD)

G6PD enzyme is essential for protecting red cell proteins from oxidative damage. NADPH generated by G6PD enzyme is used for glutathione reduction. This brings back hemoglobin to the soluble form and helps in maintaining the oxidation ratio of glutathione, providing protection against the oxidative damage [1]. G6PD deficiency phenotype ranges from mild to acute hemolytic anemia.

Pyruvate Kinase Deficiency (PKD)

Pyruvate Kinase deficiency is an inherited disorder that affects RBC resulting in hemolysis [3]. Pyruvate Kinase generates ATP by converting phosphoenolpyruvate to lactate [1]. PKD phenotype ranges from mild to acute hemolysis, splenomegaly, and anemia [1].

Both disorders affect RBC causing hemolysis and anemia. The Lorrca deformability and Osmoscan test can be used in the research of above-mentioned RBC enzyme disorders

Sickle Cell Disease

There has been a recent explosion in the interest among investigators in both the hematologic academic community and in the pharmaceutical industry to develop new treatments for sickle cell disease. There are various new therapies and drugs focusing on different modes of action to prevent SCD events and complications. The Lorrca Oxygenscan provides a parameter that is independent of the patient-reported outcome but is an indication of the severity of the disease as described in Rab et al., 2019 [4].

Thalassemia

The Lorrca Osmoscan measures red blood cell (RBC) deformability, osmotic fragility, and cell hydration. It is a valuable technique in research of Thalassemia as it can distinguish ß-Thalassemia from RBC membrane disorders. As an example, Krishnevskaya et al., 2021 [5] describes how the Lorrca Osmoscan supports distinguishing iron deficiency anemia from ß-Thalassemia.

Malaria

Reduced deformability of the red blood cell (RBC) contributes to the pathogenesis of malaria parasites by impairing RBC circulation through systemic capillaries and splenic slits. Little is known about the reduced deformability of uninfected RBCs during malaria and their handling by the spleen. Lorrca deformability measurements showed that RBCs were less deformable during acute malaria compared to healthy subjects. Reduced RBC deformability in malaria has been attributed to increased rigidity of malaria infected RBCs and, quite interestingly, of uninfected RBCs as well [6, 7, 8].

Sepsis

Sepsis is the response to infection that can be life threatening at times. It can cause hypothermia, hypotension, high blood lactate levels, reduced blood flow, increased heartbeat, and sepsis related anemia [10]. This condition weakens the immune system and can lead to stroke, multiple organ failure and heart failure [12]. Sepsis causes endothelium barrier dysfunction that dysregulates the harmony within the microcirculation [13]. The changes in RBC rheology are observed in intensive care unit patients, mainly suffering from sepsis [14]. According to the Reggiori et al., RBC aggregation and deformability is altered in critical patients with sepsis compared to the control group [10]. Another study by Donadello K et al., reported increase in RBC aggregation and decrease in deformability in critical patients with sepsis. The study further suggested that the reduced deformability over time is associated with increased mortality [15].

Since these parameters play an important role in sepsis morbidity, the Lorrca deformability and aggregation tests can be used in the research of sepsis.

Deformability at different levels of shear is a known measure of the RBC’s condition. The Lorrca can accurately measure RBC properties such as deformability related to shear as indicator perfusion quality. Deformability related to osmolality can be measured as indicator of cell fragility and ion pump functioning. Aggregation to measure the speed at which the cells flock together into rouleaux and the strength needed to separate the rouleaux again is another indicator for perfusion quality

Engineered RBCs appeared into a new class of cellular medicines. This technology harnesses both the unique properties of RBCs and the creative potential of engineering to deliver on the promise of cellular therapy and transform how diseases are treated. The Lorrca Deformability and Osmoscan tests are well suited to determine the deformability characteristics of these engineered RBCs to assure these cells are not immediately sequestered in the spleen.

RBCs have several mechanisms to neutralize reactive oxygen species (ROS) that cause oxidative stress. With the presence of RBCs throughout the body, they function as a sink for oxidative stress. However, excess oxidative stress can cause RBCs to become less deformable. This way the RBC’s deformability can become a biomarker for research into oxidative stress.

With the help of Starrsed ESR instruments, various diseases that can affect RBC sedimentation rate such as tuberculosis, rheumatoid arthritis, multiple myeloma, and temporal arteritis are being explored. Our focus is to aid in diagnosis of such diseases that can help patients start early treatment.

1. Li H, Lykotrafitis G. Erythrocyte membrane model with explicit description of the lipid bilayer and the spectrin network. Biophys J. 2014;107(3):642-653. doi:10.1016/j.bpj.2014.06.031
   
   
2. Barcellini W, Bianchi P, Fermo E, et al. Hereditary red cell membrane defects: diagnostic and clinical aspects. Blood Transfus. 2011;9(3):274-277. doi:10.2450/2011.0086-10
   
   
3. Da Costa L, Suner L, Galimand J, Bonnel A, Pascreau T, Couque N, Fenneteau O, Mohandas N; Society of Hematology and Pediatric Immunology (SHIP) group; French Society of Hematology (SFH). Diagnostic tool for red blood cell membrane disorders: Assessment of a new generation ektacytometer. Blood Cells Mol Dis. 2016 Jan;56(1):9-22. doi: 10.1016/j.bcmd.2015.09.001. Epub 2015 Sep 16. PMID: 26603718; PMCID: PMC4811191.
   
   
4. Rab, M., Van Oirschot, B., Bos, J., Merkx, T., Van Wesel, A., Abdulmalik, O., Safo, M., Versluijs, B., Houwing, M., Cnossen, M., Riedl, J., Schutgens, R., Pasterkamp, G., Bartels, M., Van Beers, E., Van Wijk, R; Rapid and reproducible characterization of sickling during automated deoxygenation in sickle cell disease patients. Am. Journal of Hematology 2019 Feb; 94:575–584.
   
   
5. Krishnevskaya, E., Payán-Pernía, S., Hernández-Rodríguez, I., Sevilla, Á. F. R., Serra, Á. A., Morales-Indiano, C., et al. (2021). Distinguishing iron deficiency from beta-thalassemia trait by new generation ektacytometry. Int. J. Lab Hematol. 43, e58–e60. doi: 10.1111/ijlh.13362
   
   
6. Prchal JT, Gregg XT. Red cell enzymes. ASH Education Program Book. 2005;2005(1):19-23
   
   
7. https://www.who.int/news-room/fact-sheets/detail/malaria
   
   
8. Mohandas N, An X. Malaria and human red blood cells. Med Microbiol Immunol. 2012 Nov;201(4):593-8. doi: 10.1007/s00430-012-0272-z. Epub 2012 Sep 11. PMID: 22965173; PMCID: PMC3699179.
   
   
9. Grace RF, Glader B. Red Blood Cell Enzyme Disorders. Pediatr Clin North Am. 2018 Jun;65(3):579-595.
   
   
10. https://medlineplus.gov/ency/article/001197.htm accessed 02/08/21
    
    
11. Dellinger R, et al., Surviving Sepsis Campaign Guidelines Committee including the Pediatric Subgroup Surviving Sepsis Campaign, Critical Care Medicine: 2013 – Volume 41 – Issue 2 – p 580-637.
    
    
12. https://www.healthline.com/health/septic-shock#diagnosis
    
    
13. Hotchkiss RS, et al., Sepsis and septic shock. Nat Rev Dis Primers. 2016;2:16045.
    
    
14. Reggiori G, et al., Early alterations of red blood cell rheology in critically ill patients. Critical care medicine. 2009;37(12):3041-6.
    
    
15. Donadello K, et al., Reduced red blood cell deformability over time is associated with a poor outcome in septic patients. Microvascular research. 2015;101:8-14