Impact of altered venous hemodynamic conditions on the formation of platelet layers in thromboemboli

Although it is generally believed that the structure of venous thromboemboli is a homogeneous red blood cell-fibrin clot, their structure may be heterogeneous, with non-uniformly distributed platelet layers, known as the lines of Zahn. We tested (a) whether venous thromboemboli ex vivo contained platelet layers, i.e. the lines of Zahn, and (b) whether, according to mathematical modeling, eddies can arise in the venous system, possibly contributing to platelet aggregation. The structure of venous thromboemboli ex vivo was determined by high-resolution magnetic resonance imaging (MRI) and by immunohistochemistry (IHC). High-resolution ultrasound (US) imaging was employed to determine the popliteal vein geometry and hemodynamics in healthy subjects and in subjects with previous venous thrombosis. The US data were then used as input for numerical simulations of venous hemodynamics. MRI and IHC confirmed that 42 of 49 ex vivo venous thromboemboli were structurally heterogeneous with platelet layers. The peak venous flow velocity was higher in patients with partly recanalized deep vein thrombosis than in healthy subjects in the prone position (46 ± 4 cm/s vs. 16 ± 3 cm/s). Our numerical simulation showed that partial venous obstruction with stenosis or malfunctioning venous valves creates the conditions for eddy blood flow. Our experimental results and computer simulation confirmed that the heterogeneous structure of venous thromboemboli with twisted platelet layers may be associated with eddy flow at the sites of their formation.     

Anemia correction by erythropoietin reduces BNP levels, hospitalization rate, and NYHA class in patients with cardio-renal anemia syndrome

Little is known about the effect of anemia correction with erythropoietin (EPO) on B-type natriuretic peptide (BNP) levels, NYHA class, and hospitalization rate. The aim of the study was to investigate, in patients with cardio-renal anemia syndrome, the effects of EPO on hemochrome and renal function parameters and BNP levels. We also analyzed the effect of EPO therapy on hospitalization rate and NYHA class after 12 months in comparison with a population undergoing to standard therapy. We performed a randomized double-blind controlled study of correction of the anemia with subcutaneous α (group A n = 13) or β (group B n = 14) EPO for 12 months in addition to standard therapy with oral iron in 27 subjects. Control group (n = 25 patients) received only oral iron. Significant increase in hemoglobin (Hb), hematocrit (Hct), and red blood cells (RBC) were revealed in EPO groups at 12 months; Hb, group A 12.3 ± 0.6; group B 11.7 ± 0.8; control group 10.6 ± 0.5 g/dl P < 0.0001; Hct group A 34.2 ± 2.3, group B 34 ± 2, control group 32.3 ± 1.8% P < 0.01; RBC, group A 3.9 ± 0.2, group B 3.8 ± 0.2, control group 3.3 ± 0.2, (P < 0.0001). Plasma BNP levels in EPO groups were significantly reduced after 12 months (group A: 335 ± 138 vs. group B: 449 ± 274 pg/ml control group 582 ± 209 pg/ml (P < 0.01). After 12 months of treatment, hospitalization rate and NYHA class were reduced in EPO groups with respect to control group (P < 0.05). Finally, an inverse correlation was observed between BNP and Hb levels in EPO Groups (r = −0.70 P < 0.001). EPO treatment reduces BNP levels and hospitalization rate in patients with cardio-renal anemia syndrome. The correction of anemia by EPO treatment appears able to improve clinical outcome in this subset of patients with heart failure.     

The Relationship of Ghrelin and Adiponectin with Bone Mineral Density and Bone Turnover Markers in Elderly Men

Body weight is commonly considered a significant predictor of bone mineral density (BMD). Adiponectin, an adipocyte-derived hormone, could modulate BMD. Moreover, recent studies have reported that ghrelin is able to stimulate bone formation. In this study, we investigated any associations of adiponectin and ghrelin serum levels with bone turnover markers and BMD in elderly men. In 137 men aged 55 years and older (mean age 67.4 +/- 5.4 years, mean body mass index [BMI] 26.6 +/- 3.4 kg/m(2)), we evaluated serum adiponectin, serum ghrelin, body composition (fat mass and lean mass), BMD, bone alkaline phosphatase (ALP), and the carboxy-terminal telopeptide of type I collagen (betaCTX). Ghrelin showed significant correlations with BMD at the femoral neck (r = 0.25, P < 0.01), total femur (r = 0.22, P < 0.05), and whole body (r = 0.18, P < 0.05). However, after adjusting for age, BMI, and calcium intake, the correlation remained significant only for femoral neck BMD. Ghrelin showed a significant correlation with lean mass but not with fat mass and bone turnover markers. Adiponectin showed a positive association with both bone ALP and betaCTX; the correlation between adiponectin and bone ALP (r = 0.25, P < 0.01) remained significant after adjusting for confounding variables. No significant correlations between adiponectin and BMD at all skeletal sites were observed. In conclusion, our study suggests that in elderly Italian men serum ghrelin was significantly associated with femoral neck BMD and that adiponectin was positively associated with bone ALP. Further studies are needed to elucidate the role of adipocytokines in bone metabolism.