Erythrocyte Aggregation and Erythrocyte Membrane Properties in Type 2 Diabetes mellitus and in Vascular Atherosclerotic Disease

Relationship of thrombus characteristics to the incidence of angiographically visible distal embolization in patients with ST-segment elevation myocardial infarction treated with thrombus aspiration

OBJECTIVES

This study sought to investigate the association between pathological characteristics of aspirated intracoronary thrombi and the incidence of angiographically visible distal embolization (AVDE) during primary percutaneous coronary intervention (p-PCI) in patients with ST-segment elevation myocardial infarction (STEMI) treated with thrombus aspiration.

BACKGROUND

AVDE of atherosclerotic and thrombotic material has been shown to impair myocardial perfusion and contribute to poor clinical outcome in patients with STEMI. Recent studies have shown that thrombus composition and size are associated with the incidence of AVDE.

METHODS

Aspirated thrombi from 164 STEMI patients within 12 h of symptom onset were investigated immunohistochemically using antibodies against platelets, erythrocytes, and inflammatory cells.

RESULTS

The angiographic results showed that AVDE during p-PCI occurred in 22 (13.4%) patients. Pathological analysis revealed that thrombi from patients with AVDE had a greater erythrocyte-positive area (60 ± 15% vs. 43 ± 21%, p < 0.0005) and more myeloperoxidase-positive cells (943 ± 324 cells/mm(2) vs. 592 ± 419 cells/mm(2), p < 0.0005) than those from patients without AVDE. Thrombus size, quantified as the thrombus surface area, was positively correlated with the erythrocyte component (r = 0.362, p < 0.0001). Moreover, multivariate logistic analysis demonstrated that erythrocyte-positive area in the thrombi, glucose levels on admission, larger vessel diameter (≥ 3.5 mm), and pre-balloon dilation were independent predictors of the incidence of AVDE.

CONCLUSIONS

This study demonstrated that the erythrocyte-rich component of aspirated thrombi may be associated with the incidence of AVDE during p-PCI in patients with STEMI.

Red blood cell membrane mechanical fluctuations in non-proliferative and proliferate diabetic retinopathy

PURPOSE

To study whether cell membrane mechanical fluctuation (CMF) of red blood cells (RBCs) are attenuated in non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).

PATIENTS AND METHODS

Point dark-field microscopy-based recordings of local membrane displacements (frequency 0.3-25 Hz) were compared between type 2 diabetes patients with mild-to-moderate and severe NPDR and type 2 diabetes patients with PDR. The matched control group, corresponding to each stage of diabetic retinopathy, was based on non-diabetic patients who were evaluated in our clinic due to cataract.

RESULTS

The average mean values of the maximal CMF amplitude did not differ between RBCs of NPDR patients (n=20) and controls (n=20) (19.5+/-1.5% and 19.6+/-1.7%, respectively). A statistically significant decrease in CMF amplitudes was observed in patients with PDR compared with patients with a non-proliferative disease (NPDR -20%, PDR -90%).

CONCLUSION

This new rheological characteristic demonstrates differences in the mechanical properties of RBCs in different stages of diabetic retinopathy. The significant reduction in CMF in patients with PDR may shed more light on the possible mechanism modulating retinal ischemia and leading to angiogenesis in these patients. Larger-scale studies are needed to evaluate these findings and the possible correlation between significantly lower CMF values and the progression of diabetic retinopathy.

The appearance of aggregated erythrocytes in the peripheral blood of individuals with insulin resistance

BACKGROUND

Insulin resistance is associated with low-grade inflammatory response. The probability that the acute-phase response is associated with enhanced erythrocyte adhesiveness/aggregation was not explored.

METHODS

The degree of erythrocyte adhesiveness/aggregation was evaluated by using a simple slide test. The insulin resistance was evaluated by insulin and glucose concentrations after a night of fasting. The inflammatory response was evaluated by variables of acute-phase response.

RESULTS

A significant correlation (r = -0.2, p = 0.02) was noted between insulin resistance expressed as the HOMA index and the degree of erythrocyte adhesiveness/aggregation. This was probably due to the concomitant acute-phase response and the presence of increased amounts of inflammation-sensitive proteins that were found to correlate significantly with the degree of erythrocyte adhesiveness/aggregation. In the multiple linear regression analysis, erythrocyte sedimentation rate and fibrinogen concentration but not HOMA index were found to correlate significantly (p < 0.0001 and p = 0.0007 respectively) with the degree of red blood cell adhesiveness/aggregation.

CONCLUSIONS

Insulin resistance is associated with an enhanced degree of erythrocyte adhesiveness/aggregation and this is related to the presence of enhanced inflammation-sensitive plasma proteins that are part of the acute-phase response. These findings might have hemorheological consequences and might contribute to the pathophysiology of the insulin-resistance syndrome.

A leukocyte and erythrocyte adhesiveness/aggregation test to reveal the presence of smoldering inflammation and risk factors for atherosclerosis

The number of white blood cells in the peripheral blood, the presence of inflammation, increased fibrinogen concentrations and hyperlipidemia are established risk factors for atherosclerosis. It is known that hyperfibrinogenemia and hyperlipidemia cause increased erythrocyte aggregation, that inflammation will confer increased adhesive properties upon white blood cells and that the increased number of white blood cells can be detected in the peripheral blood. Therefore, we adopted a simple slide test and image analysis to determine the number of peripheral blood leukocytes and their state of adhesiveness/aggregation together with an erythrocyte adhesiveness/aggregation test to reveal the presence of these risk factors. The significant correlation between the fibrinogen and cholesterol concentration and the erythrocyte aggregation, between the white blood count and the number of leukocytes on the slides, and between the concentration of C-reactive protein and leukocyte adhesiveness indicate that we have succeeded in designing a simple one-step screening test that will identify patients at risk for atherosclerosis.