Adherence of sickle (SS) erythrocytes to endothelial cells represents interactions between red blood cell (RBC) and endothelial cell surface molecules. To enhance our understanding of the ligands involved, we transfected COS cells with the cDNAs of two endothelial cell adhesion molecules, VCAM-1 and E-selectin, and measured the binding of normal and sickle RBCs after static incubation. The perc...

During storage, red blood cells (RBCs) for transfusion purposes suffer progressive deterioration. Sialylated glycoproteins of the RBC membrane are responsible for a negatively charged surface which creates a repulsive electrical zeta potential. These charges help prevent the interaction between RBCs and other cells, and especially among each RBCs. Reports in the literature have stated that RBCs...

BACKGROUND Within erythrocytes (RBCs), cAMP levels are regulated by phosphodiesterases (PDEs). Increases in cAMP and ATP release associated with activation of β-adrenergic receptors (βARs) and prostacyclin receptors (IPRs) are regulated by PDEs 2, 4 and PDE 3, respectively. Here we establish the presence of cytosolic PDEs in RBCs and determine a role for PDE5 in regulating levels of cGMP. MAT...

Infusion of epinephrine-activated human sickle erythrocytes (SS RBCs) into nude mice promotes both SS RBC and murine leukocyte adhesion to vascular endothelium in vivo. We hypothesized that interaction of epinephrine-stimulated SS RBCs with leukocytes leads to activation of leukocytes, which then adhere to endothelial cells (ECs). In exploring the underlying molecular mechanisms, we have found ...

Gaucher disease (GD) is a lysosomal storage disorder caused by glucocerebrosidase deficiency. It is notably characterized by splenomegaly, complex skeletal involvement, ischemic events of the spleen and bones, and the accumulation of Gaucher cells in several organs. We hypothesized that red blood cells (RBCs) might be involved in some features of GD and studied the adhesive and hemorheologic pr...

Hemorrhage is a common clinical manifestation in patients with cancer. Intratumor hemorrhage has been demonstrated to be a poor prognostic factor for cancer patients. In this study, we investigated the role of RBCs and hemoglobin (Hb) in the process of tumor progression and therapeutical response. RBCs and Hb potently promoted tumor cell proliferation and syngenic tumor growth. RBCs and Hb acti...

Previous studies have shown that approximately 20% of hemoglobin is lost from circulating red blood cells (RBCs), mainly during the second half of the cells' life span. Because hemoglobin-containing vesicles are known to circulate in plasma, these vesicles were isolated. Flow cytometry studies showed that most RBC-derived vesicles contain hemoglobin with all hemoglobin components present. The h...

Recent studies suggest that pericytes around capillaries are contractile and able to alter the diameter of capillaries. To investigate the effects of capillary dilation on network dynamics, we performed simulations in artificial capillary networks of different sizes and complexities. The unequal partition of hematocrit at diverging bifurcations was modeled by assuming that each red blood cell (...

Human normal and sickle red blood cells (RBCs) adhere with high affinity to the alpha5 chain of laminin (LAMA5) via the basal cell adhesion molecule/Lutheran (BCAM/Lu) receptor, which is implicated in vasoocclusive episodes in sickle cell disease and activated through the cyclic adenosine monophosphate (cAMP) signaling pathway. However, the effect of the cAMP pathway on the expression of active...

When red blood cells (RBCs) pass constrictions or small capillaries they need to pass apertures falling well below their own cross section size. We used different means of mechanical stimulations (hypoosmotic swelling, local mechanical stimulation, passing through microfluidic constrictions) to observe cellular responses of human RBCs in terms of intracellular Ca2+-signaling by confocal microsc...