Scanning electron microscopy analysis of erythrocytes in thromboembolic ischemic stroke

INTRODUCTION : Erythrocytes play an important role in hemostasis and disease conditions. During ischemic stroke, erythrocytes undergo oxidative and proteolytic changes resulting in a changed cellular rheology. METHODS : Blood samples were obtained from controls and thromboembolic ischemic stroke patients (within 48 h of stroke). The ultrastructure of erythrocytes was compared, using a scanning electron microscope (SEM). Abnormal morphology included codocytes, knizocytes,stomatocytes, and echinocytes. Percentage of abnormal cells was calculated, and the analyses were performed using the statistical program NCSS with the level of significance set at 0.05. A t-test was carried out to compare the data from the erythrocyte counts of stroke patients with that of the control subjects. RESULTS : Ultrastructural SEM results showed that there are a large percentage of erythrocytes in healthy individuals that do not have a typical discoid shape, when studying the cells using a high magnification electron microscope. Furthermore, analysis showed that variation in shape is so subtle that it is not clearly visible using a typical light microscopy blood smear analysis. Thromboembolic ischemic stroke patients presented with a significant amount of erythrocytes with abnormal morphology. CONCLUSION: We suggest that in healthy individuals, a typical smear would contain several nondiscoid-shaped erythrocytes, only clearly visible at high magnification. However, thromboembolic ischemic stroke does significantly impact erythorcyte shape, and this change in morphology may result in an impaired microcirculation, as well as impaired oxygen carrying capacity. This changed morphology may further complicate the restoring of homeostasis caused by acute thromboembolic stroke.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1751-553Xhb2016Physiolog

Prevention and follow-up in thromboembolic ischemic stroke : do we need to think out of the box?

Stroke is one of the most debilitating thrombotic diseases, and world-wide it is estimated that by, 2030, 23 million people will be affected. Except for the impact on the individual families, the world economy is also affected adversely. Although the medical treatment and knowledge of stroke are both increasing and wellresearched, we still do not see a decrease in stroke prevalence. Currently various diagnostic tests are employed to determine the specific type of ischemic stroke as classified by the TOAST criteria. However, these tests are done after the stroke has occurred and therefore only contribute to the unquestionably crucial aspect of treating that particular stroke patient, but it does not improve prevention of future events. Prevention strategies regarding first-time stroke need urgent attention given the alarming present and future incidence of stroke. Therefore, here we discuss the importance of stroke prevention and suggest amore inclusive, perhaps “new” comprehensive approach for pre-stroke screening.Ultrastructural tests, particularly scanning electron microscopy, provide an innovative and novel advance in preventative and individualized patient-centered precision medicine. This precise technique when used in combination with well-established methods, as well as viscoelastic methods like thromboelastography (TEG), as a screening tool to prevent stroke can ultimately alleviate the financial and economical burden of stroke and also improve quality of life. Although we appreciate the fact that this suggestion might be difficult to accept by clinicians, a bold new approach is needed to address this pandemic we call stroke.NRF and MRC of South Africa.http://www.elsevier.com/locate/thromres2016-12-31hb201

Ultrastructural analysis of platelets during three phases of pregnancy : a qualitative and quantitative investigation

OBJECTIVES : In the past, platelet morphology during normal pregnancy has not been given much attention. METHODS : Electron microscopy analysis of platelets from 60 pregnant individuals (30 early pregnancy (weeks 8-14) participants and 30 late pregnancy (weeks 36-40) participants which were followed up 6-8 weeks post-partum) were compared to platelets from 30 non-pregnant individuals as well as each other to establish whether differences in platelet morphology exist during pregnancy. RESULTS : Ultrastructural changes pertaining to the external and internal arrangements of platelets were visible. Fixated platelets showed pseudopodia formation and membrane blebbing. Increased and enlarged open canalicular system pores, pseudopodia formation, platelet spreading, and membrane blebbing were visible in vital platelets. Platelets from pregnancy were tightly packed and internal structures were different from the non-pregnant group. The internal granules showed modification in their occurrence within the cell. The α- and lysosomal granule counts were significantly increased during pregnancy while dense granule and mitochondrial numbers were significantly decreased. DISCUSSION : This may point to a pregnancy-specific modification. The changes in platelet ultrastructure discerned in this study attribute to the hypercoagulable state associated with pregnancy. All ultrastructural alterations associated with pregnancy persist for at least 2 months after birth.National Research Foundation (NRF) of South Africahttp://www.maneyonline.com/loi/hem2016-01-31hb201

Erythrocyte–platelet interaction in uncomplicated pregnancy

Maternal and fetal requirements during uncomplicated pregnancy are associated with changes in the hematopoietic system. Platelets and erythrocytes [red blood cells (RBCs)], and especially their membranes, are involved in coagulation, and their interactions may provide reasons for the changed hematopoietic system during uncomplicated pregnancy.We review literature regarding RBC and platelet membrane structure and interactions during hypercoagulability and hormonal changes. We then study interactions between RBCs and platelets in uncomplicated pregnancy, as their interactions may be one of the reasons for increased hypercoagulability during uncomplicated pregnancy. Scanning electronmicroscopy was used to study whole blood smears from90 pregnant females in different phases of pregnancy. Pregnancy-specific interaction was seen between RBCs and platelets. Typically, one or more platelets interacted through platelet spreading and pseudopodia formation with a single RBC. However, multiple interactions with RBCs were also shown for a single platelet. Specific RBC–platelet interaction seen during uncomplicated pregnancy may be caused by increased estrogen and/or increased fibrinogen concentrations. This interaction may contribute to the hypercoagulable state associated with healthy and uncomplicated pregnancy and may also play a fundamental role in gestational thrombocytopenia.http://journals.cambridge.org/action/displayJournal?jid=MAM2015-12-30hb201

Editorial : Pathological changes in erythrocytes during inflammation and infection

No abstract available.https://www.frontiersin.org/journals/physiologydm2022Physiolog

Synthetic hormones and clot formation

Combined oral contraceptives (COCs), colloquially referred to as "the pill," have been regarded as a medical breakthrough, as they have improved the lives of countless women, from simplifying family planning to the treatment of acne, endometriosis, polycystic ovarian syndrome, and dysmenorrhea. Unfortunately, COC usage has been associated with an increased occurrence of venous thrombosis and therefore a systemic hypercoagulable state in susceptible females. Here we discuss the health risks of COC usage and use viscoelastic and morphological techniques to investigate the effect of different COC constituents on clot formation, particularly fibrin network packaging and whole blood viscoelasticity. Viscoelastic properties of whole blood showed gender-specific changes while morphological alterations were person-specific, regardless of gender. Using scanning electron microscopy and thromboelastography provides great insight regarding fibrin packaging and the development of a hypercoagulable state in high-risk individuals. We proposed a three-step approach where (1) an individual's coagulation profile baseline is determined, after which (2) the "ideal" combination of constituents is prescribed, and (3) the coagulation profile of the individual is monitored to assess possible risk of thrombosis. Only in following such an individualized patient-oriented approach will we be able to avoid the many health issues due to COC usage in susceptible females.http://journals.cambridge.org/action/displayJournal?jid=MAM2017-02-28hb2016Physiolog

Flow cytometric comparison of platelets from a whole blood and finger-prick sample : impact of 24 hours storage

In this study, we investigate the validity and laboratory utility of flow cytometry when analyzing platelet activation by studying CD41, CD42b, CD62P and CD63. We compare flow cytometry results from citrated whole blood and finger-prick samples directly after collection and also after storing both a finger-prick and whole blood sample for 24 hours. Citrated whole blood and finger-prick samples were taken from three healthy individuals on two occasions, and a total of 60 000 cells were analyzed for each of the 4 phycoerythrin-labelled monoclonal antibodies. Half of each sample was analyzed immediately after sampling while the other half was kept in the fridge at 6°C for 24 hours before analysis. No significant difference was found between the sampling methods or the period of time before analysis. Results therefore suggest that an appropriately prepared finger-prick sample can be used for platelet function analysis, and samples can be stored for 24 hours in the fridge at 6°C before analysis.http://www.maneyonline.com/loi/hemhb2016Physiolog

Viscoelasticity and ultrastructure in coagulation and inflammation : two diverse techniques, one conclusion

The process of blood clotting has been studied for centuries. A synopsis of current knowledge pertaining to haemostasis and the blood components, including platelets and fibrin networks which are closely involved in coagulation, are discussed. Special emphasis is placed on tissue factor (TF), calcium and thrombin since these components have been implicated in both the coagulation process and inflammation. Analysis of platelets and fibrin morphology indicate that calcium, tissue factor and thrombin at concentrations used during viscoelastic analysis (with thromboelastography or TEG) bring about alterations in platelet and fibrin network ultrastructure, which is similar to that seen in inflammation. Scanning electron microscopy indicated that, when investigating platelet structure in disease, addition of TF, calcium or thrombin will mask disease-induced alterations associated with platelet activation. Therefore, washed platelets without any additives is preferred for morphological analysis. Furthermore, morphological and viscoelastic analysis confirmed that thrombin activation is the preferred method of fibrin activation when investigating fibrin network ultrastructure.http://link.springer.com/journal/107532016-08-04hb201

Tissue factor levels in type 2 diabetes mellitus

INTRODUCTION : Type 2 diabetes mellitus is a pandemic associated with disturbance inhaemostasis that could contribute to the development of diabetic vascular disease and accelerated atherosclerosis. In this population, hypercoagulation is prevalent, as well as pathological changes to erythrocytes. This is mainly due to upregulated circulating inflammatory markers. MATERIALS AND METHODS : Here we looked at tissue factor (TF) levels using ELISA, in a sample of diabetics, with and without cardiovascular complications. Diabetic subjects were recruited from the diabetic clinic at Steve Biko Academic Hospital, Pretoria, South Africa. 20 diabetics with cardiovascular disease and 22 without were enrolled to participate. RESULTS AND CONCLUSION : TF levels were significantly elevated in both diabetic groups when compared to the controls. We suggest that pathologic plasma TF activity, as marker of increased propensity of clot pathology, should be investigated. Agents that might lower TF levels might also possibly lower thrombotic complications.This work is based on the research supported in part by the National Research Foundation of South Africa (UNIQUE GRANT NO: 92709) and the MRC : E Pretorius (fund number A0X331).http://link.springer.com/journal/112018-05-28hb2017Physiolog

Part 2 : Ultrastructural changes of fibrin networks during three phases of pregnancy : a qualitative investigation

INTRODUCTION: Normal pregnancy is characterized by significant alterations in the haemostatic system accompanied by an augmented risk of thrombosis. MATERIALS AND METHODS: The fibrin network ultrastructure of different phases of pregnancy, namely early pregnancy (week 8 – 14), late pregnancy (week 36 – 40) as well as post-partum (week 6 – 8 after birth) were compared to non-pregnant fibrin networks as well as each other to establish whether differences in fibrin network morphology exist during pregnancy. Scanning electron microscopy was employed to analyse fibrin network morphology. RESULTS: The fibrin networks from all phases of pregnancy appeared similar to each other, exhibiting prominent coagulant formation, an increase in the formation of minor, thin fibers, and the presence of granular globules. Al three phases however differ from the typical fibrin network ultrastructure exhibited by the fibrin networks from non-pregnant individuals. The increase in estrogen associated with pregnancy may cause the increase in coagulation factors and ultimately the pro-thrombotic state characteristic of pregnancy. CONCLUSIONS: Since no differences were apparent between the different phases of pregnancy it suggests that activation of the coagulation system commences with pregnancy and this pro-thrombotic state continues till at least 8 weeks after birth. These results may shed light on possible pathological mechanisms employed in the development of abnormal or ailing pregnancy.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1097-0029hb201