Michela Cortiana

Endothelial precursors and mature endothelial cells are increased in the peripheral blood of myelodysplastic syndromes

Increased angiogenesis has been demonstrated to be a significant prognostic factor in many solid tumors. In the oncohematological setting, it has been associated with myelodysplastic syndromes (MDS), chronic myeloid leukemia, acute lymphoid, and myeloid leukemias. Recently, increased circulating endothelial cells (CECs) have been associated with breast cancer and non-Hodgkin lymphoma (NHL). Based on these premises we analysed total and activated CECs, and endothelial precursors (CEPs) in 50 MDS patients and 20 healthy donors. CECs and CEPs were quantified by flow cytometry. CEC levels were compared with bone marrow (BM) microvessel density (MVD). In addition, some angiogenic factors, namely vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and soluble VEGF-Receptor2 (VEGFR2), were tested in the sera from 25 MDS patients. Total, activated CECs and CEPs were significantly increased in MDS when compared to control group (p<0.0001); whereas in the MDS cases no association was found with French--American--British (FAB), International Prognostic Scoring System (IPSS) subtypes or survival. Patients with higher CECs also showed higher MVD. Among the cytokines analysed, sVEGFR2 was significantly higher in the lower IPSS risk classes, while the levels of bFGF directly correlated with total and activated CECs. Taken together these data strengthen the hypothesis of a possible role of angiogenesis in MDS pathogenesis.

Pulmonary arterial hypertension in primary myelofibrosis is common and associated with an altered angiogenic status

Pulmonary arterial hypertension in primary myelofibrosis is common and associated with an altered angiogenic status

Endothelial Colony Forming Capacity is Related to C-Reactive Protein Levels in Healthy Subjects

The majority of clinical studies on endothelial progenitor cells (EPCs) focuses on the role of these cells in cardiovascular diseases and no systematic studies exist regarding their variations in healthy subjects. In order to define the burden of angiogenesis in physiological conditions we assessed the frequency of peripheral blood endothelial colonies (PB-ECs) and their relation with other factors possibly involved in their function such as high-sensitivity C-reactive protein (hs-CRP), endothelial cell-specific mitogen factor (VEGF) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in a highly selected healthy population. A PB sample was obtained from 37/47 healthy subjects (age 40.2+/-15.0yrs; M/F 15/22) without known cardiovascular risk factors. The serum level of hs-CRP, VEGF, TIMP-1, the frequency of PB-ECs by clonogenic assay, and the number of early EPCs and late EPCs by flow cytometry analysis were evaluated. PB-ECs were formed by 40.5% of studied subjects with a mean of 0.40+/-0.82 colonies/10(6) cells. The differences in the frequency of colony formation between genders were not statistically significant. The subjects with PB-ECs were characterized by higher values of hs-CRP, when compared with those not forming colonies, 0.276+/-0.230 vs 0.095+/-0.077 mg/l (p=0.003) respectively, and of VEGF, 328.3+/-162.9 vs 202.68+/-118.53 pg/ml (p=0.02). No significant differences were found in TIMP-1 values. The EPC clonogenic potential seems to be related to hs-CRP and VEGF levels even in healthy population supporting the concept that these mediators are involved in physiological ECs function.

Effects of simulated altitude (normobaric hypoxia) on cardiorespiratory parameters and circulating endothelial precursors in healthy subjects

BackgroundCirculating Endothelial Precursors (PB-EPCs) are involved in the maintenance of the endothelial compartment being promptly mobilized after injuries of the vascular endothelium, but the effects of a brief normobaric hypoxia on PB-EPCs in healthy subjects are scarcely studied.MethodsClinical and molecular parameters were investigated in healthy subjects (n = 8) in basal conditions (T0) and after 1 h of normobaric hypoxia (T1), with Inspiratory Fraction of Oxygen set at 11.2% simulating 4850 mt of altitude. Blood samples were obtained at T0 and T1, as well as 7 days after hypoxia (T2).ResultsIn all studied subjects we observed a prompt and significant increase in PB-EPCs, with a return to basal value at T2. The induction of hypoxia was confirmed by Alveolar Oxygen Partial Pressure (PAO2) and Spot Oxygen Saturation decreases. Heart rate increased, but arterial pressure and respiratory response were unaffected. The change in PB-EPCs percent from T0 to T1 was inversely related to PAO2 at T1. Rapid (T1) increases in serum levels of hepatocyte growth factor and erythropoietin, as well as in cellular PB-EPCs-expression of Hypoxia Inducible Factor-1α were observed.ConclusionIn conclusion, the endothelial compartment seems quite responsive to standardized brief hypoxia, possibly important for PB-EPCs activation and recruitment.