Electron confocal and atomic force microscopic analysis of platelets fibrin and erythrocytes in atopic asthma
Year: 2018
Type: dissertation
Study design: Observational Study
Abstract: Background: The underlying risk factor of non-communicable diseases is\ninflammation. The pathophysiology of asthma and/or allergic asthma is also, no\nsurprisingly, also linked to chronic inflammation. The prevalence and incidence of\nasthma is on the increase, despite of a variety of treatment modalities. Asthma\ntherefore is a growing burden on healthcare system and on society.\nAsthma pathophysiology is not only linked to inflammation, but also with\nactivation of coagulation and reduced fibrinolysis due to plasma and locally derived\nfactors in the airways. Alterations to these factors may thus influence the biophysical\nand mechanical properties of the coagulation, fibrin deposition followed by asthma\npathology.\nMethodology: The objective of this study was to evaluate changes of blood\ncomponents in asthma patients (n=30) compared to controls (n=30) using routine\nhaematology screening using a haematology analyser; structural changes and axial\nratio analysis using light microscopy (erythrocytes), elasticity using atomic force\nmicroscopy (erythrocytes); ultrastructural changes using scanning electron\nmicroscopy (erythrocytes, platelets and fibrin), transmission electron microscopy\n(platelets) and confocal microscopy (platelets) as well as the viscoelastic properties\nof the fibrin clot using thromboelastography; and mRNA levels of FXIII-A in whole\nblood by quantitative PCR.\nResults: The haematology findings of controls and asthma patients were within\nnormal clinical ranges. There was, however, a significantly higher level of circulating\nmonocytes (p=0.0066), erythrocytes (p=0.0004), haemoglobin (p=0.0057) and\nhaematocrit (p=0.0049).\nThe analysis of eosin stained erythrocytes by light microscopy showed more\nechinocytes, acanthocytes and ovalocytes compared to controls and the axial ratio\nwas also significantly higher (controls: 1.2�0.22nm vs. asthma: 1.165�0.16nm,\np<0.0001). Atomic force microscopy findings showed significantly reduced\nerythrocyte membrane elasticity (p=0.001). Morphological changes of erythrocytes\nwere also noted from scanning electron microscopy. Platelet morphology and ultrastructure were qualitatively assessed using scanning\nelectron microscopy, transmission electron microscopy and confocal microscopy and\nshowed morphological changes indicative of platelet activation in asthma samples.\nIn addition, the assessment of clot kinetics by thromboelastography also\nshowed alteration with a tendency to produce stronger fibrin clots in asthma\nsamples. The reaction time was higher (p<0.0001), alpha-angle was lower\n(p<0.0001), maximum rate of clot formation was higher (p<0.0001) � all indicative of\na longer time for clotting to occur but the maximal amplitude which is indicative of\nclot strength and stability was significantly higher in asthma samples (p=0.0478). As\nthe aggregation and cross-linking of fibrin fibres depends on factor XIII (FXIII), its\nexcessive production may lead to alterations in fibrin polymerisation and crosslinking\nresulting in stronger fibrin clot formation and resistance to fibrinolysis. Densitometry\nanalysis of scanning electron microscopy images of fibrin fibres showed a\nsignificantly lower variance in asthma samples (p<0.0001) indicative of more matt\nlike structures compared to normal fibrin fibres in controls.\nThe analysis of gene expression by qPCR revealed a significant 17.34-fold\nhigher FXIII-A mRNA level in whole blood of asthma patients compared to controls\nindicating greater potential for de novo production of FXIII-A compared to the control\ngroup. These results would facilitate further research possibilities for identifying\npotential biomarkers in allergic asthma.\nThese findings support the hypothesis of this study: enhanced coagulation\nmay be attributed to the altered morphology and activation of platelets, erythrocyte\nand fibrin networks in asthma.\nConclusion: In conclusion, altered erythrocyte and platelet morphology, excess\nproduction of FXIII-A, altered fibrin architecture and clot properties affects the\ncoagulation profile in asthma, systemically. Further research is needed to extrapolate\nexact mechanism by which increased systemic coagulation contributes to the\npathophysiology of the disease locally.
Author: Sajee Alummoottil
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2908028706