Differential impact of bortezomib on HL-60 and K562 cells.

Bortezomib (PS-341, or Velcade), reversible inhibitor of 20S proteasome approved for the treatment of multiple myeloma and mantle cell lymphoma, exhibited a cytotoxic effect toward other malignancies including leukaemia. In this study, we have documented that incubation of both HL-60 and K562 leukaemia cells with nanomolar concentrations of bortezomib is associated with the death of HL-60 cells observed within 24 hours of incubation with bortezomib and the death of K562 cells that were observed after 72 hours of incubation with bortezomib. The relative resistance of K562 cells to bortezomib correlated well with significantly higher expression of HSP27, HSP70, HSP90α, HSP90ß and GRP75 in these cells. Incubation of both HL-60 and K562 cells with bortezomib induced a cleavage of HSP90ß as well as expression of HSP70 and HSP90ß but bortezomib did not affect levels of HSP27, HSP90α, GRP75 and GRP78. The death of both types of cells was accompanied with proteolytic activation of caspase 3 that was observed in HL-60 cells and proteolytic degradation of procaspase 3 in K562 cells. Our study has also pointed to essential role of caspase 8 in bortezomib-induced cleavage of HSP90ß in both HL-60 and K562 cells. Finally, we have shown that bortezomib induced activation of caspase 9/caspase 3 axis in HL-60 cells, while the mechanism of death of K562 cells remains unknown.

Therapeutic angiogenesis for the critical limb ischemia decreases platelet activation.

Platelets are required for the recruitment of bone marrow-derived mononuclear cells (BMMNC) into ischemia-induced vasculature, which underlines their key role in angiogenesis. The difference in platelet immunophenotype between healthy controls and patients with critical limb ischemia (CLI) treated with therapeutic angiogenesis (TA) using BMMNC was assessed. The impact of TA on the expression of platelet membrane markers was studied as well. CLI patients (N = 26) and blood donors as controls (N = 21) were enrolled. Bone marrow (600 ± 50 ml) was centrifuged (3200 g, 20 min, 22 °C). BMMNC (100-120 ml) were separated by Optipress I and implanted to the ischemic limb using deep intramuscular injections. Flow cytometry was employed for the peripheral blood platelets immunophenotyping. CD41FITC, CD62PE, CD36FITC, CD29FITC antibodies were used. Patients were followed up prior to the procedure and at months 1, 3 and 6. The expression of CD41 was lower in CLI patients than in the controls. P-selectin (CD62P) was higher in CLI patients than in controls at the baseline and at month 6. It was significantly down-regulated at month 3, however not at months 1 and 6 compared to baseline. Platelet GPIV (CD36) was higher at the baseline, but not during the follow-up compared to the controls. ß1-integrin (CD29) progressively decreased during the follow-up as compared to the baseline value. Platelets in CLI express P-selectin, GPIV and ß1-integrin more abundantly than platelets of healthy subjects. TA down-regulates the expression of the respective markers. Possible mechanism could be higher clearance of the activated platelets in the ischemic tissues during angiogenesis.

Therapeutic angiogenesis improves fibrinolytic imbalance in patients with critical limb ischemia.

The mechanisms of fibrinolysis have been suggested to be linked to the pathogenesis of peripheral artery disease. The impact of therapeutic angiogenesis on the parameters of fibrinolysis was studied in critical limb ischemia (CLI). CLI patients (N = 29) and blood donors as controls (N = 29) were enrolled. Bone marrow (600 ±â€Š50 ml) was centrifuged (3200g, 20 min, 22°C), bone marrow-derived mononuclear cells (100-120 ml) were separated by Optipress I and implanted into the ischemic limb using intramuscular injections. ELISA was employed for the assessment of plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) levels. Patients were followed-up prior to the procedure and after 1, 3 and 6 months. All stage-IV patients (N = 22) had ischemic lesions. The lesions resolved in 10 patients. Five patients underwent major amputation; they all were stage-IV. Ischemic lesions persisted in seven patients beyond 6 months. The t-PA levels were higher in patients compared with the healthy controls both at baseline (P < 0.01) and after 6 months (P < 0.05). No significant changes were observed in the t-PA levels during the follow-up. PAI-1 was higher in patients than in the healthy individuals at baseline (P < 0.001) and at month 1 (P < 0.05). However, no difference in PAI-1 levels between the patients and the healthy individuals was found after 3 and 6 months. The PAI-1 levels were significantly downregulated during the follow-up compared with the baseline (P < 0.0001). Therapeutic angiogenesis for the CLI downregulates PAI-1 levels, thus having a systemic effect on fibrinolysis.

Nine kindreds of familial sticky platelet syndrome phenotype.

INTRODUCTION: Sticky platelet syndrome (SPS) is most likely a hereditary thrombophilia characterized by platelet hyperaggregation after low concentrations of platelet inducers--adenosine diphosphate and/or epinephrine. We present 9 kindreds with SPS familial occurrence. MATERIAL AND METHODS: Familial trait of SPS was looked up in the database of the National Center of Hemostasis and Thrombosis. Families with at least 3 SPS-positive members were studied, described, and presented. RESULTS: In the group of 1093 symptomatic patients, SPS was confirmed in 240 cases. Familial occurrence with at least 3 SPS-positive relatives was found in 9 cases. CONCLUSION: The exact pathogenesis of SPS is not sufficiently explained. Our findings seem to support the idea that SPS might have an autosomal dominant hereditary fashion.

Variability of GP6 gene in patients with sticky platelet syndrome and deep venous thrombosis and/or pulmonary embolism.

The GP6 gene encodes the GPVI, a crucial platelet membrane glycoprotein, for adequate platelet activation, adhesion and aggregation. The objectives of the present study were to assess the genetic variability of the GP6 gene in patients with platelet hyperaggregability phenotype, known as sticky platelet syndrome (SPS) manifesting as deep vein thrombosis (DVT), and/or pulmonary embolism, and in controls; and to evaluate its role in the pathogenesis of venous thromboembolism (VTE) in SPS. Seventy-seven patients with SPS and 77 healthy blood donors as controls were enrolled. Light transmission aggregometry was used to diagnose SPS according to the method of Mammen and Bick. Seven single-nucleotide polymorphisms (SNPs) of the GP6 gene (rs1654410, rs1671153, rs1654419, rs11669150, rs12610286, rs1654431, rs1613662) were assessed using restriction fragment length polymorphism analysis. A significant association between 1613662-G [P < 0.05, odds ratio (OR) 2.087, confidence interval (CI) 1.049-4.148], 1654419-A (P < 0.05, OR 2.161, CI 1.020-4.577) and VTE was found in patients with SPS. The analysis based on SPS type revealed a significantly higher occurrence of 1671153-G (P < 0.05, OR 2.317, CI 1.103-4.865) and 1654419-A (P < 0.05, OR 2.317, CI 1.103-4.865) in the SPS type II compared to the control group. No association between the studied GP6 genotypes and the severity of VTE (pulmonary embolism vs. DVT) was found. In the patients, significant positive relationship between the 1671153-G, 1654419-A, 1613662-G alleles and male sex was observed. GP6 SNPs 1613662-G, 1671153-G and 1654419-A alleles are associated with an increased risk of VTE in SPS. They could contribute to the SPS phenotype.

The relationship among TAFI, t-PA, PAI-1 and F1 + 2 in type 2 diabetic patients with normoalbuminuria and microalbuminuria.

Disturbances of coagulation and fibrinolysis in type 2 diabetes mellitus (DM2) contribute to increased rates of macrovascular complications such as myocardial infarction and ischemic stroke. The aim of the study was to investigate the relationship among plasminogen activator inhibitor 1 (PAI-1), thrombin-activable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (t-PA), prothrombin fragments 1+2 (F1+2), glycemic control, hypertension, sex and body mass index (BMI) in DM2 patients with normoalbuminuria and microalbuminuria. Forty-two normoalbuminuric (NAU), 42 microalbuminuric (MAU) patients with DM2 and 42 blood donors as control group were enrolled. TAFI, PAI-1, t-PA and F1+2 were assessed by enzyme-linked immunosorbent assay (ELISA) in all patients. TAFI was significantly increased in the MAU group, PAI-1 and F1+2 were increased in both groups and t-PA was not elevated in either group compared to controls. We found positive correlations in the NAU: TAFI and fibrinogen (r=0.65, P=0.02), PAI-1 and triglycerides (r=0.67, P=0.01), in the MAU: TAFI and F1+2 (r=0.48, P=0.02), TAFI and systolic blood pressure (r=0.53, P=0.01), PAI-1 and BMI (r=0.43, P<0.05). We found decreased fibrinolysis in DM2 patients presented with increased PAI-1 in both NAU and MAU. Hypofibrinolysis in MAU is further accented by the elevation of TAFI. TAFI-mediated inhibition of fibrinolysis in DM2 is regulated independently from PAI-1. Patient[Combining Acute Accent]s sex does not affect diabetes-related changes in hemostasis and fibrinolysis.

Circulating vascular endothelial growth factor in the normo- and/or microalbuminuric patients with type 2 diabetes mellitus.

Relationship between serum vascular endothelial growth factor (VEGF) level and parameters of endothelial injury and/or dysfunction in patients with diabetes mellitus type 2 with or without microalbuminuria was investigated. Eighty-four diabetic patients were divided in two subgroups (42 each): normoalbuminuric (NAU) and microalbuminuric (MAU). Forty-two blood donors were in control group. Serum VEGF and plasma von Willebrand factor, soluble thrombomodulin, plasminogen activator inhibitor 1, thrombin-activatable fibrinolysis inhibitor (TAFI) and tissue plasminogen activator (t-PA) were measured using enzyme-linked immunosorbent assay in all subjects. VEGF was significantly higher in NAU compared to controls. The difference between MAU and controls was not statistically significant, but there was a trend toward significance. Only TAFI correlated with VEGF in MAU. An observed significant increase of serum VEGF level already in NAU suggests that serum VEGF could be a sensitive predictor of endothelial dysfunction in type 2 diabetes.