Morphological Features of Red Blood Cells in Patients with Severe Concomitant Injury

Abstract

Objective: to reveal changes in the structure and shape of red blood cells depending on blood loss (BL) volume in patients with severe concomitant injury (SCI). Subjects and methods. Eighteen patients (9 men, 9 women) aged 48.6±16.1 years who had sustained severe concomitant mechanical injury (CMI) with different BL volumes and hemodynamic disorders were examined. According to the volume of BL, the patients were divided into two groups: 1) 7 victims with a BL volume of < 750 ml (5.7±1.9 ml/kg), grade 1 BL; 2) 11 victims with a BL volume of > 2000 ml (37.5±5.1 ml/kg), grade 4 BL. A comparison group consisted of 5 apparently healthy volunteers whose mean age was 26.4±2.7 years. The shapes and sizes of red blood cells were examined by light optical and atomic force microscopy (AFM). To study the composition of red blood cells, ten microliters of whole blood were applied to the slides and red blood cell monolayers were prepared using a V-sampler. The membrane surface was scanned by semicontact resonance AFM. The investigators used NSGL 01-A cantilevers with a resonance frequency in the range of 80200 kHz, a probe radius of 10 nm, 512 and 1024 scanning points, and 100X100 ^m and 10X10 ^m scanning fields. Planar and 3D images were obtained. Results. Calculation of 1000 cells by light optical microscopy and AFM showed significantly different counts of macro- and microcytes in the comparison group. The 100X100-^m field exhibited the following types of red blood cells: discocytes (97.9±1.5% and 96±5%), echinocytes (2.1±0.9% and 3±1%), and squamous cells (0.1±0.02% and 1±0.5%). Within the first 24 hours after injury, the victim group displayed lower normocyte counts and higher counts of macrocytes and microcytes than the control group. AFM in the 100X100-^m field revealed that the victims with SMI when admitted to an intensive care unit exhibited a significant decrease in the counts of discocytes counts and increases in those of echinocytes, stomatocytes, and squamous cells, as compared to the controls. Anisocytosis and poikylocytosis was found to depended on the degree of BL. The squamous cells are most likely to be a variety of young erythrocytes. An appreciable increase in macrocytes and squamous cells on day 5 most likely reflects enhanced compensatory erythropoiesis in response to BL. Examination of red blood cell shapes within the first 24 hours after injury in the AFM field revealed profound discocytes with a protuberance in the center. On day 1 of injury changes in the nanostructure of red blood cell membranes included: 9-fold increase of first-order height (hj); 1.5-fold and 3-fold increase of second- and third-order heights (h2 and h3), respectively. The magnitude of changes in hj, h2 and h3 depended on the volume of BL and tended to decrease within the first two weeks of injury. Conclusion. The victims with SMI were observed to possess significant anisocytosis and poikylocytosis. The changes were associated with the volume of BL and included profound discocytes with a protuberance in the center as well aso changes in heights of nanostructural patterns of red blood cell membranes. Key words: severe concomitant injury, blood loss, atomic force microscopy, light optical microscopy, nanostructure of red blood cell membranes.