INFLAMET: an image analyzer to display erythrocyte adhesiveness/aggregation

Assessment of Red Blood Cell Aggregation in Preeclampsia by Microfluidic Image Flow Analysis-Impact of Oxidative Stress on Disease Severity

Preeclampsia (PE) is a hypertensive disease characterized by proteinuria, endothelial dysfunction, and placental hypoxia. Reduced placental blood flow causes changes in red blood cell (RBC) rheological characteristics. Herein, we used microfluidics techniques and new image flow analysis to evaluate RBC aggregation in preeclamptic and normotensive pregnant women. The results demonstrate that RBC aggregation depends on the disease severity and was higher in patients with preterm birth and low birth weight. The RBC aggregation indices (EAI) at low shear rates were higher for non-severe (0.107 ± 0.01) and severe PE (0.149 ± 0.05) versus controls (0.085 ± 0.01; p < 0.05). The significantly more undispersed RBC aggregates were found at high shear rates for non-severe (18.1 ± 5.5) and severe PE (25.7 ± 5.8) versus controls (14.4 ± 4.1; p < 0.05). The model experiment with in-vitro-induced oxidative stress in RBCs demonstrated that the elevated aggregation in PE RBCs can be partially due to the effect of oxidation. The results revealed that RBCs from PE patients become significantly more adhesive, forming large, branched aggregates at a low shear rate. Significantly more undispersed RBC aggregates at high shear rates indicate the formation of stable RBC clusters, drastically more pronounced in patients with severe PE. Our findings demonstrate that altered RBC aggregation contributes to preeclampsia severity.

Role of red blood cell flow behavior in hemodynamics and hemostasis

The primary role of red blood cells (RBCs) is to transport oxygen to the tissues, which is performed predominantly in the blood capillaries. However, RBCs have unique flow-affecting properties that play a key role in blood flow in all blood vessel types and sizes. While RBCs as oxygen carriers have been studied extensively, their hemodynamic function has been examined less comprehensively. This review aims to bridge this gap, focusing on the role of RBC flow properties in hemodynamics, hemostasis and thrombosis.

Extracellular methemoglobin primes red blood cell aggregation in malaria: an in vitro mechanistic study

Toxic byproducts from infected RBC cause rheological alteration and RBC aggregation. Malaria culture supernatant has the ability to exhibit RBC aggregation. Ammonium sulfate fractionation and immunodepletion of methemoglobin from culture supernatant confirms methemoglobin as a major aggregant. In vitro treatment of RBC with methemoglobin induces irreversible high order RBC aggregates, resistant to shear stress and physical forces. Methemoglobin-mediated ROS generation in the external micro-environment to develop oxidative stress close to RBC membrane seems to be responsible for initiating and forming high order RBC aggregates through phosphatidyl-serine externalization. Removal of oxidative stress through antioxidant treatment abolishes high order RBC aggregate formation. In conclusion, we discovered a novel pathway of methemoglobin-mediated RBC aggregation and its potential role in patho-physiological effects during malaria.

Increased erythrocyte adhesiveness and aggregation in obstructive sleep apnea syndrome

BACKGROUND

Obstructive sleep apnea (OSA) is associated with an increased incidence of stroke and myocardial infarction as well as increased prothrombotic and inflammatory processes. Although erythrocyte adhesiveness/aggregation is known to be elevated in cardiovascular diseases, it has never been evaluated in OSA. The aim of this study was to examine the possible association of OSA and erythrocyte adhesiveness/aggregation.

METHODS

The study was conducted in the Sleep Laboratory of a tertiary university-affiliated medical center in 79 patients (age 57.1+/-12.9 years) with a diagnosis of OSA (apnea hypopnea index 41.2+/-25.9). Findings were compared with data on 1079 controls without clinical symptoms of OSA, matched for sex, age, and body mass index. Overnight polysomnography and blood sampling for erythrocyte sedimentation rate, levels of fibrinogen, high-sensitivity C-reactive protein, and erythrocyte adhesion/aggregation test consisting of measures of erythrocyte percentage and vacuum range on image analysis.

RESULTS

The study group had significantly higher values than controls of all three markers of inflammation (p<0.001 for erythrocyte sedimentation rate and fibrinogen; p=0.037 for C-reactive protein). Erythrocyte percentage was significantly lower in the sleep apnea group (84.05+/-15.97 vs. 90.79+/-11.23%, p<0.001), and vacuum range was significantly higher (8.22+/-7.98 vs. 4.63+/-4.05 microm, p<0.001), indicating stronger erythrocyte adhesion/aggregation. Both these factors were significantly correlated with erythrocyte sedimentation rate and to hs-CRP (percentage: r=-0.630; 0.258, p=0.005; 0.031; vacuum range: r=0.494; -0.328, p=0.001; 0.005 respectively).

CONCLUSION

OSA is associated with increased erythrocyte aggregation/adhesion, which is correlated with an increase in inflammation markers. These findings might help explain the increased cardiovascular morbidity in OSA.

Erythrocyte aggregation is increased in preterm premature rupture of the membranes

OBJECTIVE

To asses the degree of erythrocyte aggregation in the peripheral blood of women with preterm premature rupture of the membranes (PPROM).

STUDY DESIGN

This was a prospective case control study. Twenty patients with preterm premature rupture of the membranes and matched controls were recruited at the Lis Maternity Hospital. A slide test and image analysis were used to quantitate the degree of erythrocyte aggregation. Hematological indices and markers of inflammation such as the erythrocyte sedimentation rate and C-reactive protein were also compared.

RESULTS

The vacuum radius (VR) of the study group was significantly higher than in the control group at 14.8+/-1.6 microm versus 10.0+/-1.0 microm, respectively (P=0.03). Other hematological indices were not changed significantly between the groups.

CONCLUSIONS

We found an increase in erythrocyte aggregation in the peripheral blood of patients with preterm premature rupture of the membranes. We used this sensitive marker of inflammation to further support the theory that PPROM is an inflammatory state.

Use of nebulized budesonide in two critical patients with hydrocarbon intoxication

Reports of acute naphtha (a petroleum distillate) intoxication, particularly those containing treatment and toxicological data, are poorly verified in the literature. Systemic steroids have not usually been advised for routine management, but no previous studies have been reported on the effects of corticosteroid inhalations. In this study, two critical pediatric patients with chemical pneumonia due to naphtha ingestion have been reported who were effectively managed with nebulized budesonide.

Enhanced Erythrocyte Aggregation in Clinically Diagnosed Pelvic Inflammatory Disease

OBJECTIVE

Enhanced erythrocyte aggregation, revealed using a simple bedside test, has been found recently in several inflammatory conditions. The diagnosis of pelvic inflammatory disease (PID) is at times difficult because of the vague symptoms and signs, but is crucial because even mild PID can have future reproductive consequences. Our objective was to determine the degree of erythrocyte aggregation in PID. The demonstration of an increase in aggregation could be of additive value in cases in which the diagnosis is difficult.

STUDY DESIGN

A prospective case-control study was conducted. Fifteen consecutive women diagnosed clinically as having PID based on Centers for Disease Control and Prevention criteria, and 15 matched controls were enrolled. Blood samples were drawn for hematologic indices, C-reactive protein, fibrinogen levels, and red cell aggregation. We studied the degree of red cell aggregation using a simple slide test and image analysis. The variable measured was the erythrocyte percent (EP), equivalent to the slide area covered by erythrocytes.

RESULTS

Erythrocyte percent was 59.6 +/- 4.2 and 80.0 +/- 3.6 for the study group and controls, respectively (P <0.001). A significant difference was noted also for the other hematologic and biochemical markers of inflammation between patients and the controls.

CONCLUSIONS

We conclude that the degree of erythrocyte aggregation is increased in PID. Its simplicity, rapidity, and low cost should be further evaluated as a diagnostic tool in the context of this frequent disease.

The Erythrosense as a Real-Time Biomarker to Reveal the Presence of Enhanced Red Blood Cell Aggregability in Atherothrombosis

This paper reviews the longitudinal studies in which the association between hypertension and cognitive functioning has been explored. The findings of these studies are far from being consistent: positive, adverse, or no relationships between cognitive performance and blood pressure have been reported. In some studies, cognitive functioning was related only to systolic blood pressure, whereas in others, it was related to diastolic blood pressure alone. Most probably, the inconsistency is due to the variability in research design, the measures employed, and data management. Some of the main methodological issues are the wide range in the age of the subjects and the variability in hypertension at baseline. Length of exposure to hypertension was rarely considered, and the search for the possible effects of the different antihypertensive treatments on cognitive ability is in its infancy. Many studies seek to identify cognitively impaired elderly and do not distinguish between the different types of dementia or the different cognitive domains. Thus, the possibility that hypertension affects specific cognitive functions has not been explored. The use of subdivisions of blood pressure values may have obscured nonlinear relationship. Nevertheless, the pattern that emerges is that midlife hypertension enhances cognitive impairment later in life, but at old age, mild hypertension may increase cognitive performance. Directions for future research to further elucidate the complex relationship between age, blood pressure, and cognition are discussed.

The Erythrosense as a Real-Time Biomarker to Reveal the Presence of Enhanced Red Blood Cell Aggregability in Atherothrombosis

Both anemia and inflammation might be present in individuals with atherothrombosis. We have evaluated the eventual influence of these 2 variables on the degree of erythrocyte adhesiveness/aggregation in the peripheral blood of 583 women and 402 men with various atherothrombotic risk factors and vascular events. It turned out that both anemia and inflammation (highly sensitive C-reactive protein concentrations) influence the degree of cell adhesiveness/aggregation and that there is no interaction between them. Thus, the degree of erythrocyte adhesiveness/aggregation might have the diagnostic advantage of being enhanced in individuals with atherothrombosis who have inflammation and no anemia as well as those who have anemia and no inflammation. These findings might help to turn a phenomenon of hemorheological relevance into a diagnostic tool for the detection of individuals at risk of an acute ischemic event.

The Erythrosense as a Real-Time Biomarker to Reveal the Presence of Enhanced Red Blood Cell Aggregability in Atherothrombosis

A common mode of deep vein thrombosis prophylaxis in medical inpatients is unfractionated heparin 5000 U subcutaneously (s.q.) twice daily. We examined the evidence in favor of using this dose of heparin in this group of patients. MEDLINE was searched for studies using the words deep vein thrombosis prophylaxis and heparin. All randomized controlled trials comparing heparin and placebo or heparin and a low molecular weight heparin were used. Relative risk was 0.4 (95% confidence interval 0.22-0.73) in studies comparing heparin 5000 U s.q. b.i.d. with placebo. Relative risk was 0.28 (95% confidence interval 0.21-0.38) in studies comparing heparin 5000 units s.q. t.i.d. versus placebo. In studies comparing unfractionated heparin with enoxaparin relative risk was 1.42 (95% confidence interval 0.99-2.05). Heparin 5000 U s.q. b.i.d. is less efficacious than low molecular weight heparins and unfractionated heparin 5000 U s.q. t.i.d.

Inflammation-sensitive proteins and erythrocyte aggregation in atherothrombosis

OBJECTIVE

To find the relative contribution of various inflammation-sensitive proteins including fibrinogen, immunoglobulins (IgG, IgM and IgA), ceruloplasmin and high sensitivity C-reactive protein (hs-CRP) to the induction and/or maintenance of enhanced erythrocyte adhesiveness/aggregation in the peripheral blood of individuals with atherothrombotic risk factors.

METHODS

The degree of erythrocyte adhesiveness/aggregation was determined by a simple slide test and image analysis. In addition, we measured various inflammation-sensitive protein levels including fibrinogen, ceruloplasmin, immunoglobulins and hs-CRP in a group of 234 individuals with atherothrombotic risk factors and healthy ones. Pearson partial correlations and multiple linear regression analysis were performed.

RESULTS

Fibrinogen was found to be the major protein contributing to the enhanced erythrocyte adhesiveness/aggregation, explaining 30% of the model. Fibrinogen and IgG together explained 32.4% of the model. Other inflammation-sensitive proteins did not reach statistical significance and were excluded from the model.

CONCLUSIONS

Among inflammation-sensitive proteins measured in our cohort, fibrinogen is the dominant contributor to erythrocyte adhesiveness/aggregation in the peripheral blood of individuals with atherothrombotic risk factors and healthy ones. These findings may pave the way for the development of therapeutic strategies directed at the attenuation of erythrocyte aggregability in individuals with atherothrombosis.

Erythrocyte adhesiveness/aggregation: a novel biomarker for the detection of low-grade internal inflammation in individuals with atherothrombotic risk factors and proven vascular disease

BACKGROUND

We have introduced a concept of using the erythrocyte as a sensor for the detection of enhanced inflammation-sensitive protein concentrations. We presently evaluated the capability of this new biomarker to detect the presence of inflammation in individuals with a history of a vascular disease as opposed to individuals with atherothrombotic risk factors but no clinically evident vascular disease.

METHODS

The degree of erythrocyte adhesiveness/aggregation was determined in the peripheral venous blood by using a simple blood test. Blood was drawn into a syringe containing sodium citrate and trickled onto a slide at an angle of 30 degrees. The slides were than scanned by a blinded technician by using an image analyzer to determine the area that is covered by the erythrocytes.

RESULTS

One hundred fifty-six subjects (61 women and 95 men) of 2586 (1238 women and 1348 men) met the criteria of a definite vascular disease (history of stroke, myocardial infarction, coronary artery bypass grafting, or peripheral vascular disease). The degree of erythrocyte aggregation was significantly (P = .008) higher in men, but not in women, with vascular disease as opposed to these without a vascular disease. The results of receiver operating characteristic curve analysis confirmed the diagnostic superiority of the erythrocyte aggregation biomarker over other commonly used markers of the acute phase in men. Similar results were obtained by using discriminant analysis. Finally, a significant correlation was found between the degree of erythrocyte aggregation and other markers of the acute phase suggesting its relevance for the detection and quantitation of low-grade inflammation in individuals with atherothrombosis.

CONCLUSION

Erythrocyte adhesiveness/aggregation may be a useful biomarker to detect internal inflammation in individuals with atherothrombosis.

Rheological determinants in patients with Gaucher disease and internal inflammation

The purpose of this study was to determine whether the inflammatory response in patients with Gaucher disease (GD) is accompanied by enhanced adhesiveness/aggregation of both red and white blood cells. Sixty patients with GD and matched controls were included. The degree of erythrocyte and leukocyte adhesiveness/aggregation was determined by using a simple slide test and image analysis. Patients with GD had significantly elevated concentrations of fibrinogen (328 vs. 262 mg/dl, P < 0.0001) and accelerated erythrocyte sedimentation rates (27 vs. 13 mm/H, P < 0.005). This was accompanied by a significantly enhanced degree of erythrocyte (75 vs. 85, P < 0.0001) and leukocyte (3.5 vs. 1.3, P < 0.002) adhesiveness/aggregation. The low-grade, smoldering, and subclinical internal inflammation in individuals with GD is accompanied by an increased degree of erythrocyte and leukocyte adhesiveness/aggregation. These findings might have rheological consequences in terms of microcirculatory slow flow and tissue hypoxemia.

Sex differences in the expression of haemorheological determinants in individuals with atherothrombotic risk factors and in apparently healthy people

BACKGROUND

Increased red cell aggregation can be detrimental, leading to slow capillary blood flow and tissue hypoxaemia. Sex differences in the degree of erythrocyte adhesiveness/aggregation in the peripheral blood have not been clearly shown.

OBJECTIVES

To determine whether there are sex differences in the expression of erythrocyte adhesiveness/aggregation in the peripheral blood in individuals with atherothrombotic risk factors and in apparently healthy people.

METHODS

From a cohort of 965 participants in the Tel Aviv Medical Centre inflammation survey, 192 pairs of different sex were matched for age, body mass index, hip and waist circumferences, cardiovascular risk factors, and the intake of active cardiovascular drugs.

RESULTS

Women had an enhanced degree of red cell aggregation (p < 0.0005) as well as increased concentrations of inflammation sensitive proteins including fibrinogen and C reactive protein. Women had a lower haemoglobin concentration than men, but this did not affect the degree of erythrocyte adhesiveness/aggregation.

CONCLUSIONS

The significant increase in red blood cell adhesiveness/aggregation in the peripheral blood of women with atherothrombosis could be relevant to the more eventful course that some women experience during and following acute ischaemic disease.

A synergistic effect of albumin and fibrinogen on immunoglobulin-induced red blood cell aggregation

Therapeutic administration of immunoglobulins (Ig) has the potential to precipitate thrombotic events. This phenomenon may be explained by red blood cell (RBC) aggregation, which can be potentiated by Ig. The contribution of plasma albumin and fibrinogen to Ig-induced RBC aggregation is unclear. We examined RBC aggregation in three settings: 1) patients receiving therapeutic infusions of Ig; 2) patients receiving plasma supplemented in vitro with Ig; and 3) patients receiving RBC suspensions in standard buffer with varying concentrations of albumin, Ig, and fibrinogen. Ig infusion augmented aggregation of RBCs from patients with normal or high plasma levels of albumin but decreased aggregation in those with lower plasma albumin concentrations. In vitro, RBC aggregation was significantly increased only when all three components, fibrinogen, albumin, and Ig, were present at or above normal concentrations in the suspension but was unaffected when any one of the components was absent from the suspension. Our results suggest a three-way interaction among fibrinogen, Ig, and albumin that synergistically induces RBC aggregation in plasma. Understanding these interactions may help predict clinically important phenomena related to RBC aggregation, such as thrombotic complications of Ig infusion.

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.

Prognostic implications of admission inflammatory profile in acute ischemic neurological events

OBJECTIVE

To reveal the potential prognostic implications of admission inflammatory markers in patients with acute ischemic neurological events.

PATIENTS AND METHODS

Sixty patients with an acute ischemic neurological event who were examined within 24 h from the appearance of symptomatology. We determined the high-sensitive C-reactive protein (hs-CRP) concentrations, erythrocyte sedimentation rate (ESR), fibrinogen concentrations and degree of erythrocyte adhesiveness/aggregation.

RESULTS

A significant correlation was noted between baseline hs-CRP concentrations, ESR as well as adhesiveness/aggregation and the outcome of the ischemic neurological event as determined by the modified Rankin scale 8-12 months following the insult.

CONCLUSION

Admission inflammatory markers have long-term prognostic implications in patients with acute ischemic neurological events. These findings are relevant in view of the new therapeutic interventions now available for reducing the inflammatory response.

The erythrocyte adhesiveness/aggregation test for the detection of an acute phase response and for the assessment of its intensity

We have developed a simple slide test and image analysis to reveal the state of erythrocyte adhesiveness/aggregation in the peripheral blood of patients with various degrees of the humoral acute phase response. The significant correlation between the results of the erythrocyte adhesiveness/aggregation test (EAAT), the erythrocyte sedimentation rate and fibrinogen concentration support the notion that it is possible to use the EAAT as a marker for the intensity of the acute phase response. Within a group of 860 individuals, we were able to differentiate effectively between groups of patients with a different intensity of humoral acute phase response. The present study confirms previous observations that support the applicability of the EAAT to routine clinical practice.

Superiority of a functional leukocyte adhesiveness/aggregation test over the white blood cell count to discriminate between mild and significant inflammatory response in patients with acute bacterial infections

Electronic cell counters may underestimate the white blood cell count (WBCC) in the presence of aggregated leukocytes. In the present study we focused on the possibility of using a functional, as opposed to an anatomic, count to circumvent this eventual underestimation. A model of bacterial infection was used because of the importance of leukocytosis in the physician's clinical decision-making process. There were 35 patients with low C-reactive protein (CRP) concentrations (0.5-4.9 mg/dL), 45 with intermediate (5-9.9 mg/dL), and 120 with relatively high (>10 mg/dL) CRP concentrations. A significant (P=0.008) difference was noted between the state of leukocyte adhesiveness/aggregation in the peripheral blood of individuals with low CRP concentrations (3.5%+/-4.3%) and those with high CRP concentrations (7.4%+/-8%), while there was no significant difference in the respective number of WBCs per cubic millimeter (cmm) (11,600 +/- 5,500 and 14,000 +/- 7,200, respectively). We raise the possibility that a functional test might be superior over an anatomic count in patients with acute bacterial infection and a significant acute phase response.

The usefulness of telemedicine for the detection of infection/inflammation at the point of care

The objective of this study is to examine the possibility of using Telemedicine to diagnose the presence of the inflammatory response and to assess its intensity at the point of care. One drop of citrated peripheral venous blood from 15 patients with infection/inflammation and 15 controls were used to prepare the slides. Unstained pictures were analyzed using a microscope, video camera and image analyzer (INFLAMETTM, Biovision, Tel Aviv, Israel). The jpg-compressed images were transferred via telephone to a physician in a remote location. A significant correlation was noted between the white blood cell count and the number of leukocytes per square mm by image analysis (r = 0.67 p < 0.0001 n = 30), between the degree of leukocyte adhesiveness/aggregation and the concentration of C-reactive protein (r = 0.42 p = 0.02 n = 29) and between the degree of erythrocyte aggregation and either fibrinogen concentrations (r = 0.73 p < 0.0001) or erythrocyte sedimentation (r = 0.83, p < 0.0001). No problems occurred during file transmission and there were no transfer errors. Physicians can successfully estimate the presence of an inflammatory response and its intensity using a simple slide test, image analysis, and Telemedicine technology.

The erythrocyte adhesiveness/aggregation test to reveal real-time information of rheological relevance in patients with familial and primary hypercholesterolemia before and following plasma exchange

We applied an erythrocyte adhesiveness/aggregation test (EAAT) to a model of plasma exchange in individuals with familial and primary hypercholesterolemia. The significant (p < 0.0001) reduction in the concentration of fibrinogen by 56%, globulins by 48%, and cholesterol by 53% corresponded to the expected significant (p < 0.0001) reduction in the degree of erythrocyte adhesiveness/aggregation in the peripheral venous blood. By virtue of its being a real-time, simple, very-low-cost, and essentially bedside technique, the EAAT might have the potential of disclosing information of rheological relevance immediately before, during, as well as following apheretical procedures administered to patients with an impaired rheological profile.

The usefulness of an inflammation meter to detect the presence of infection/inflammation in elderly patients

BACKGROUND

Medical personnel who work in small geriatric institutions most frequently do not have access to realtime laboratory facilities.

METHODS

In order to present a new method to determine the presence of an inflammatory response and for the assessment of its intensity, 118 patients aged 77 +/- 6 years with various bacterial infections were evaluated as well as 129 elderly individuals with various stressful conditions but no acute infections who served as controls. The leukocyte and erythrocyte adhesiveness/aggregation tests were performed by using a simple slide test and image analysis. The availability of the CD11b/CD18 and CD62L antigen on the leukocytes' surface was measured by whole blood flow cytometry, and the quantitative C-reactive protein by using laser nephelometry and specific antihuman C-reactive protein antibodies.

RESULTS

A significant difference was noted between patients and controls for all variables obtained by the slide test and image analysis. In addition, a highly significant correlation was noted between the number of leukocytes counted on the slides and white blood cell count, between the leukocyte adhesiveness/aggregation test and quantitative C-reactive protein, and between the degree of erythrocyte adhesiveness/aggregation and either the Westergren sedimentation or fibrinogen concentration.

CONCLUSIONS

By using our low-cost and real-time slide test, any medical or paramedical personnel can get relevant information regarding the presence of an acute phase response at the point of care.

Rheological determinants of red blood cell aggregation in diabetic patients in relation to their metabolic control

AIMS

To determine whether increased red blood cell adhesiveness/aggregation in diabetic patients is related to the extent of their metabolic control.

METHODS

We measured erythrocyte adhesiveness/aggregation in a group of 85 adult patients with diabetes mellitus by using citrated venous whole blood and a simple slide test. The erythrocyte adhesiveness/aggregation was determined by measuring the size of the spaces that are formed between the aggregated erythrocytes. We divided the patients into those with either low or high erythrocyte adhesiveness/aggregation values.

RESULTS

The erythrocyte adhesiveness/aggregation values of the two groups differed significantly in terms of their fibrinogen concentration, erythrocyte sedimentation rate, high sensitive C-reactive protein (CRP), total cholesterol and triglyceride concentrations. There was no difference between the two groups regarding the concentrations of HbA(1c). Logistic regression was applied to construct a model to predict the belonging of a patient in the low or high erythrocyte adhesiveness/aggregation group. A linear regression was applied to construct a model to predict the erythrocyte adhesiveness/aggregation values. Both models turned out to include gender, age, fibrinogen, triglyceride, retinopathy, coronary artery disease and age and gender interaction. Neither HbA(1c) nor CRP entered the models.

CONCLUSIONS

The degree of erythrocyte adhesiveness/aggregation and several variables of the acute-phase response in patients with diabetes mellitus are not directly related to the degree of metabolic control as evaluated by means of HbA(1c) concentration. Diabetic patients might benefit from rheological or anti-inflammatory interventions regardless of their metabolic control.

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.

The erythrocyte adhesiveness/aggregation test in the peripheral blood of patients with ischemic brain events

We adopted a simple slide test and image analysis to determine the state of erythrocyte adhesiveness/aggregation in the peripheral blood of 45 patients with acute ischemic stroke, 30 with TIA and 27 matched controls. A highly significant (P=0.005) difference was noted between patients and controls regarding the degree of erythrocyte adhesiveness/aggregation while there was no significant difference for both erythrocyte sedimentation rate or fibrinogen concentrations. We suggest that our slide test might be a low cost and real time method to detect the increased erythrocyte aggregability in the peripheral blood of patients with acute ischemic neurological events. These findings might be relevant in view of recent studies that suggest a favorable effect of therapeutic interventions directed at the improvements of this hemorrheological aspect in individuals with ischemic vascular conditions.

Combined leukocyte and erythrocyte aggregation in patients with acute myocardial infarction

OBJECTIVES

To determine whether the increased aggregability of both white and red blood cells previously reported in acute myocardial infarction (aMI) correlates with each other.

DESIGN

Cross-sectional study comparing two groups of patients and a group of healthy controls.

SETTING

A tertiary university affiliated hospital (Intensive Cardiac Care Unit and Department of General Internal Medicine).

PATIENTS

Consecutive patients with aMI, patients with chest pain and no infarction, and healthy controls.

MEASUREMENTS AND RESULTS

We adapted a simple slide test and image analysis to reveal the state of both leukocyte and erythrocyte adhesiveness/aggregation in the peripheral blood of patients with aMI. A significant (P=0.0001) increment in the aggregation of both cellular populations was noted in 48 patients with aMI as opposed to the 141 patients with ischemic heart disease and no infarction and in 45 matched controls. In addition, a significant correlation was noted between the various variables of the leukocyte and erythrocyte adhesiveness/aggregation tests.

CONCLUSIONS

The significant correlation between the aggregability of white and red blood cells in patients with aMI is suggestive of there being a commonly shared adhesive protein(s). The prompt identification of patients with increased aggregation might have clinical and therapeutic implications.

The feasibility of estimating the erythrocyte sedimentation rate within a few minutes by using a simple slide test

The acute phase response is accompanied by the appearance of aggregated red blood cells in the peripheral blood. The Westergren erythrocyte sedimentation rate (ESR) is an indirect measurement of this enhanced aggregability. We adopted a simple slide test and image analysis to reveal the adhesiveness/aggregation of red blood cells. A significant correlation was found between the erythrocyte adhesiveness/aggregation test (EAAT) and the ESR. A predictive model for ESR based on EAAT and the age of the patients was created. This new approach will enable us to obtain within a few minutes a good estimate of whether a given individual has a mild moderate or significant acute phase response. With further development, we will be able to use a bedside small cartridge that will deliver the extrapolated ESR at low costs and within a couple of minutes.