Increased erythropoiesis and subclinical inflammation as part of the metabolic syndrome.

Recent studies have suggested the insulin resistance might be accompanied by enhanced erythropoiesis. We have examined this association in individuals with the metabolic syndrome (MS) who in addition to insulin resistance harbor a chronic low grade inflammation. This study is relevant because chronic inflammation might have a suppressive effect on erythropoiesis. 280 and 554 non-smoking women and men with respective age of 46.4+/-9.3 (mean+/-S.D.) and 44.0+/-11.0 years are included. A significant correlation was noted between the numbers of the components of the MS and the inflammatory biomarkers including the white blood cell count, high sensitivity C-reactive protein, fibrinogen concentrations and the erythrocyte sedimentation rate. In addition, a significant correlation (r=0.157, p=0.008) was noted between the number of components of the MS and the number of red blood cells in the peripheral blood in women. The same was true for men (r=0.192, p<0.0005). We conclude that enhanced erythropoiesis could be a new, hitherto unrecognized component of the MS. The enhanced erythropoiesis could give an erroneous impression of general "good" health in these individuals.

Flow-resistant red blood cell aggregation in morbid obesity.

OBJECTIVE: Enhanced red blood cell (RBC) aggregation has an adverse effect on microcirculatory blood flow and tissue oxygenation. It has been previously shown that obesity is associated with increased RBC aggregation. The objectives of the present study were to further characterize obesity-related RBC aggregation and to examine whether the enhanced aggregation is a plasma- or cellular-dependent process. METHODS: Obese (body mass index (BMI)=40+/-6.3 kg/m2, n=22) and nonobese (BMI=24+/-3.4 kg/m2, n=18) individuals were evaluated for inflammation markers and aggregation parameters. Aggregation parameters were derived from the distribution of RBC population into aggregate sizes, and from the variation of the distribution as a function of flow-derived shear stress, using a cell flow properties analyzer. To differentiate plasmatic from cellular factors, we determined the aggregation in the presence of autologous plasma or dextran-500 kDa and calculated the plasma factor (PF) in the obese group. PF ranges from 0 to 1. When the PF=1, the aggregation is all due to plasmatic factors, when PF=0, the altered aggregation depends entirely on cellular factors, whereas 0

Serum lipids as minor determinants of the degree of erythrocyte adhesiveness/aggregation in the peripheral blood of individuals with low grade inflammation and moderately increased serum lipids.

Both lipids and inflammation sensitive proteins have been reported to affect the aggregation of red blood cells yet their relative importance in this regard have not been determined. We have included high sensitive C-reactive protein, erythrocyte sedimentation, fibrinogen concentrations as well as various serum lipid concentrations and the degree of erythrocyte adhesiveness/aggregation in the peripheral blood in a linear regression analysis. Partial Pearson correlation coefficients were included as well. In a group of 674 individuals with various atherosclerotic risk factors, low grade inflammation and moderately increased serum lipids, a relatively low correlation was noted between red blood cell adhesiveness/aggregation and triglycerides concentrations. A negative correlation was noted for HDL cholesterol. None of the lipid variables turned significant in the regression analysis. In a group of individuals with atherosclerotic risk factors, low grade inflammation and moderately increased serum lipids, the degree of erythrocyte adhesiveness/aggregation in the peripheral blood correlates much better with the presence of inflammation sensitive proteins than with the presence of increased lipid concentrations.

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.

Capillary and venous leukocyte adhesiveness/aggregation to differentiate between viral and bacterial infection.

BACKGROUND: A simple capillary leukocyte adhesiveness/aggregation test (CAPLAAT) might be helpful in determining the intensity of inflammation in acute viral and bacterial infections. PATIENTS AND METHODS: We included 30 patients with acute bacterial infections, 14 with viral infections as well as 48 healthy controls. The leukocyte adhesiveness/aggregation test (LAAT) test was performed using a simple slide test and image analysis. RESULTS: The CAPLAAT had a similar discrimination power between bacterial and viral infections as both the white blood cell count (WBC) and the erythrocyte sedimentation rate (ESR). It was more sensitive than the WBC and the ESR (77%, 68% and 66%, respectively) for the detection of bacterial infections and had a comparable negative predictive value. By analyzing the size distribution of the aggregated leukocytes, we found that a venous leukocyte adhesiveness/aggregation test (VLAAT) of four cells and more had the best positive predictive value (94%) and specificity (95%) for diagnosis of an acute bacterial infection (from all the acute phase response variables examined). CONCLUSION: The CAPLAAT might be attractive for the detection of inflammation and for the assessment of its severity at points of care where the services of a clinical laboratory are not available around the clock.

The leukocyte adhesiveness/aggregation test (LAAT) conveys information of biological relevance and is not a result of chance collision. Something more than another hypothesis.

The leukocyte adhesiveness/aggregation test is a sensitive marker for the detection of inflammation and for the assessment of its intensity. This has been convincingly shown by several independent groups as well as in various models of infection/inflammation. However, it has not been settled whether the concomitant appearance of leukocytosis and aggregation is a result of chance collision or not. We recently examined a group of individuals with proven acute infection/inflammation who had absolutely the same number of white blood cells in the peripheral blood and found significantly enhanced leukocyte adhesiveness/aggregation in patients as opposed to control. These findings clearly demonstrate that the phenomenon of leukocyte adhesiveness/aggregation does not result from a simple chance collision. It probably conveys a message of biological relevance reflecting both the appearance of cell adhesive molecules during activation as well as the contribution of plasmatic sticky proteins.

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.

Cutaneous involvement in a rare case of adult visceral leishmaniasis acquired in Israel.

Skin lesions are rare in visceral leishmaniasis, especially in Mediterranean countries. We describe an unusual case of visceral leishmaniasis in a 41-year-old man that began with a skin lesion. The parasites isolated from both the skin lesion and the bone marrow were typed as Leishmania donovani sensu stricto. This pathogen is not endemic in Israel or neighboring countries; its contribution to adult visceral leishmaniasis in Israel is summarized.

Correlated expression of adhesive properties for both white and red blood cells during inflammation.

The state of leukocyte and erythrocyte adhesiveness/aggregation was determined in the peripheral blood of 382 patients with infection/inflammation as well as in 72 controls by using a simple slide test and image analysis. A highly significant correlation (r = 0.4, n = 455, p < 0.001) was found between the state of leukocyte and erythrocyte adhesiveness/aggregation. The extent of both leukocyte and erythrocyte aggregation correlated with the concentration of fibrinogen. Significant aggregation of leukocytes with erythrocytes was noted as well. We conclude that both leukocyte and erythrocyte aggregation occur in the peripheral blood of patients with infection/inflammation. Such cell aggregation, which might have detrimental rheological consequences, can be detected by using our novel technique.