Growth Differentiation Factor 15 in Severe Aortic Valve Stenosis: Relationship with Left Ventricular Remodeling and Frailty.

Background: Frailty is an important outcome predictor in patients with aortic stenosis who are candidates for transcatheter or surgical aortic valve replacement (AVR). Growth/differentiation factor 15 (GDF15) is a cytokine playing a role in the pathophysiology of ventricular remodeling. We assessed its potential role as an independent soluble biomarker of frailty in these patients. Methods: We studied 62 patients (age, mean 79 years, 95% confidence interval (CI) 77-81; 54.8% female) with severe aortic valve stenosis and candidates for AVR. We systematically assessed pre-intervention GDF15 levels for their relationship with frailty (Katz score) and echocardiographic parameters of left ventricular dysfunction/remodeling. Fifteen hypertensive patients with left ventricular (LV) hypertrophy served as controls. Results: Patients with aortic valve stenosis featured higher GDF15 levels than controls (1773, 95% CI 1574-1971 pg/mL vs. 775, 95% CI 600-950 pg/mL, respectively, p < 0.0001). Subjects in the upper GDF15 tertile were older (p = 0.004), with a more advanced NYHA functional class (p = 0.04) and a higher prevalence of impaired renal function (p = 0.004). Such patients also showed a higher frailty score (p = 0.04) and higher indices of LV dysfunction, including reduced global longitudinal strain (p = 0.01) and a higher left ventricular mass (p = 0.001). GDF15 was significantly related to the Katz score, and predicted (OR 1.05; 95% CI 0.9-1.1; p = 0.03) a low (<5) Katz score, independent of the relationship with LV mass, age, renal function or indices of LV dysfunction. Conclusions: GDF15 is increased in patients with severe aortic stenosis and appears to be a soluble correlate of patients' frailty, independent of indices of left ventricular dysfunction.

Chitosan-Based Nanoparticles Containing Cherry Extract from Prunus avium L. to Improve the Resistance of Endothelial Cells to Oxidative Stress.

Cherries are known for their nutraceutical properties, in particular for their antioxidant ability due to their polyphenol content, which causes a reduction of cardiovascular disease (CVD) risk factors. However, once ingested these molecules are degraded in the Gastrointestinal (GI) tract before reaching the blood, which is the action site. The object of the present work is to evaluate the ability of cherry extract (CE), encapsulated in nanoparticles (NPs) based on different chitosan (Ch) derivatives, to promote a protective effect of human umbilical vein endothelial cells (HUVECs) involved in vascular dysfunction against oxidative stress. CE-loaded NPs based on quaternary ammonium chitosan (NP1) and an S-protected thiolated derivative thereof (NP2) were prepared. The mean particle size (NP1 344.9 ± 17.8, NP2 339.9 ± 68.2 nm), the polydispersity index, the encapsulation efficiency (NP1 78.4 ± 4.5, NP2 79.8 ± 0.6%), and the zeta potential (NP1 14.8 ± 0.3, NP2 15.8 ± 0.5 mV) did not appear to be significantly different. Both NP types improved the CE apparent permeation parameters with respect to the control. Conversely, CE-loaded NP2 protected HUVECs from oxidative stress and reduced reactive oxygen species (ROS) production more than CE-loaded NP1 and free CE. In addition to promoting HUVEC resistance, NP2 could be a useful tool to overcome the problem of cherry seasonality.

Endothelial progenitor cell secretome delivered by novel polymeric nanoparticles in ischemic hindlimb.

Endothelial progenitor cells (EPCs) contribute to ischemic tissue repair by paracrine secretion up-regulated by hypoxia. In this study we use novel nanoparticles (NPs) as carriers for a controlled release of EPC secretome (CM) to improve their angiogenic properties. The in vivo effect in ischemic hindlimb rat model was evaluated, comparing hypoxic EPC-CM-NPs with hypoxic EPC-CM alone. A proteomic characterization of hypoxic CM and the in vitro effect on endothelial cells (HUVECs) were also performed. Up to 647 protein, 17 of which with angiogenic properties, were upregulated by hypoxia. Moreover, hypoxic EPC-CM significantly promoted capillary-like structures on Matrigel. A significant increase of blood perfusion in ischemic limbs at 2 weeks with EPC-CM-loaded NPs as compared to both EPC-CM and control and a significant increase of capillary formation were observed. The use of EPC-CM-NPs significantly improved neoangiogenesis in vivo, underlining the advantages of controlled release in regenerative medicine.

Effect of aminaphtone on in vitro vascular permeability and capillary-like maintenance.

Objectives Aminaphtone, a naphtohydrochinone used in the treatment of capillary disorders, may affect oedema in chronic venous insufficiency. Aim of study is to investigate the effect of aminaphtone on vascular endothelial permeability in vitro and its effects on three-dimensional capillary-like structures formed by human umbilical vein endothelial cells. Method Human umbilical vein endothelial cells were treated with 50 ng/ml VEGF for 2 h and aminaphtone for 6 h. Permeability assay, VE-cadherin expression and Matrigel assay were performed. Results VEGF-induced permeability was significantly decreased by aminaphtone in a range concentration of 1-20 µg/ml. Aminaphtone restored VE-cadherin expression. Finally, 6 h pre-treatment with aminaphtone significantly preserved capillary-like structures formed by human umbilical vein endothelial cells on Matrigel up to 48 h compared to untreated cells. Conclusions Aminaphtone significantly protects endothelium permeability and stabilises endothelial cells organised in capillary-like structures, modulating VE-cadherin expression. These data might explain the clinical benefit of aminaphtone on chronic venous insufficiency.

The integrated value of sST2 and global longitudinal strain in the early stratification of patients with severe aortic valve stenosis: a translational imaging approach.

Aortic valve stenosis (AVS) is associated with significant myocardial fibrosis (MF). Global longitudinal strain (GLS) is a sensible indicator of systolic dysfunction. ST2 is a member of the interleukin (IL)-1 receptor family and a modulator of hypertrophic and fibrotic responses. We aimed at assessing: (a) the association between adverse LV remodeling, LV functional parameters (including GLS) and sST2 level. (b) The association between MF (detected by endo-myocardial biopsy) and sST2 in patients with AVS undergoing surgical valve replacement. Twenty-two patients with severe AVS and preserved EF underwent aortic valve replacement. They performed laboratory analysis, including serum ST2 (sST2), echocardiography and inter-ventricular septum biopsy to assess MF (%). We included ten controls for comparison. Compared to controls, patients showed higher sST2 levels (p < 0.0001). sST2 showed correlation with Age (r = 0.58; p = 0.0004), E/e' average (r = 0.58; p = 0.0007), GLS (r = 0.61; p = 0.0002), LAVi (r = 0.51; p = 0.003), LVMi (r = 0.43; p = 0.01), sPAP (r = 0.36; p = 0.04) and SVi (r = -0.47; p < 0.005). No correlation was found between MF and sST2. At ROC analysis, a sST2 ≥ 284 ng/mL had the best accuracy to discriminate controls from patients with impaired GLS, i.e. GLS ≤ 17% (AUC 0.80; p = 0.003; sensitivity 95%; specificity 83%) and increased E/e' average (AUC 0.87; p = 0.0001; sensitivity 96%; specificity 74%). At multivariate regression analysis GLS resulted the only independent predictor of sST2 levels (R2 = 0.35; p =  0.0004). Patients with severe AVS present elevated sST2 levels. LV GLS resulted the only independent predictor of sST2 levels.

Effect of different chitosan derivatives on in vitro scratch wound assay: a comparative study.

Different strategies have been developed to make the wound-healing process faster and less painful. Recently, numerous studies demonstrated the ability of chitosan to accelerate wound healing. Aim of the present study has been to evaluate the effect of different chitosan derivatives to improve wound healing process. Quaternary ammonium-chitosan conjugates with low or high molecular weight (MW) and their thiolated derivatives effect were studied on human skin fibroblasts in terms of viability and migration (scratch wound assay). Results were compared both with basal medium (untreated cells) and with a positive control (chitosan chlorhydrate). After 24h both high and low MW chitosan derivatives were non-toxic up to 10 µg/ml. The concentration of 10 µg/ml was used for wound healing experiments. High-MW quaternary ammonium-chitosan conjugates bearing thiol groups on their chains were more effective in promoting cell migration than the non-thiolated conjugates and the chitosan chlorhydrate. Moreover, they significantly improve wound healing process compared to untreated cells. According to the present in vitro preliminary results, high MW thiolated quaternary ammonium-chitosan conjugates can be considered good candidates for the management of wounds.

Significant endothelin release in patients treated with foam sclerotherapy.

BACKGROUND: Foam sclerotherapy has been proven to be a safe and effective treatment for superficial venous insufficiency, but transient visual and neurologic disturbances continue to be reported. These side effects have been theorized to be related to the presence of air or gases in the sclerosing foam that results in "bubble" migration into the cerebral circulation. We present a differing hypothesis that significant amounts of endothelin are released from the treated veins, amounts capable of causing these complications. MATERIAL AND METHODS: We tested the release of endothelin 1 (ET-1) in 12 rats after sclerotherapy with sodium tetradecyl sulfate (STS) in liquid and foam preparations. In 11 human subjects, we measured ET-1 in systemic circulation and in a draining vein after foam sclerotherapy with polidocanol. RESULTS: Rats treated with STS showed a significant increase in ET-1 levels 1 and 5 minutes after foam sclerotherapy. Patients treated with foam sclerotherapy showed a marked increase in ET-1 levels that correlated significantly with local ET-1 levels. CONCLUSIONS: Evidence of ET-1 release represents a plausible relationship explaining neurologic and visual disturbances reported after sclerotherapy.

Human peripheral blood endothelial progenitor cells synthesize and express functionally active tissue factor.

INTRODUCTION: Endothelial progenitor cells are circulating cells able to home to sites of vascular damage and to contribute to the revascularization of ischemic areas. We evaluated whether endothelial progenitor cells synthesize tissue factor, a procoagulant protein also involved in angiogenesis. MATERIALS AND METHODS: Endothelial progenitor cells were obtained from the peripheral blood mononuclear fraction of normal donors and cultured in endothelial medium supplemented with specific growth factors. The procoagulant activity expressed by cells disrupted by freeze-thaw cycles was assessed by a one stage clotting assay. Tissue factor mRNA expression was evaluated by RT-PCR. RESULTS: Endothelial progenitor cells do not express procoagulant activity in baseline conditions. However, lipopolysaccharide induces the expression of procoagulant activity. The effect is dose-dependent and reaches statistical significance at 100 ng/mL lipopolysaccharide. Inhibition with an anti-tissue factor antibody and amplification of cDNA with primers based on the tissue factor sequence confirm the identity of this activity with tissue factor. The kinetics of tissue factor expression by endothelial progenitor cells is identical to that of human umbilical vein endothelial cells showing maximal activity within 4 hours, and then decreasing; in contrast, tissue factor expression by mononuclear cells lasts for longer times. Both 5,6-dichloro-beta D-ribofuranosyl-benzimidazole and cycloheximide prevented the expression of procoagulant activity. Stimulation of endothelial progenitor cells with tumor necrosis factor-alpha did not elicit any detectable procoagulant activity. CONCLUSIONS: Endothelial progenitor cells can be stimulated by lipopolysaccharide to synthesize tissue factor. This protein might be involved in thrombotic phenomena and might contribute to endothelial progenitor cells related neovascularization.

The prostacyclin analogue iloprost increases circulating endothelial progenitor cells in patients with critical limb ischemia.

Patients with critical limb ischemia (CLI) have low levels of endothelial progenitor cells (EPC). Iloprost has been demonstrated to stimulate vascular endothelial growth factor (VEGF) and promote angiogenesis. We investigated the effects of iloprost on EPC levels in vivo in CLI patients. Twenty-three patients with stage III and IV CLI were treated with iloprost for four weeks, improving clinical and instrumental parameters. Mononuclear cells isolated from peripheral blood were cultured to obtain "early" EPC, evaluated counting adherent cells with double positivity for acetylated low-density lipoprotein uptake and Ulex Europaeus lectin at flow cytometry. These cells also co-expressed the monocyte markers CD14 and CD45. Iloprost increased EPC number in the whole patient population: pre-treatment median: 13,812/ml; range: 1,263-83,648/ml; post-treatment median: 23,739/ml; range: 3,385-99,251/ml; p = 0.035, irrespective of age, sex, disease stage or atherosclerosis risk factors. In conclusion, iloprost increases EPC number in peripheral blood in vivo. Such an effect may have therapeutic relevance.

Polymorphic analysis of the matrix metalloproteinase-9 gene and susceptibility to sporadic abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) has a multifactorial aetiology and the importance of genetic components is getting increasing interest. Alteration in the structure of the vascular extracellular matrix has been described in AAA. Matrix metalloproteinases (MMPs) degrade extracellular matrix proteins which alter the vessel wall stability. We evaluated two different polymorphisms, a CA repeat and a cytosine to thymidine transition in the promoter sequence of MMP-9 gene for frequency in 146 patients with AAA. We compared the results with those of 156 healthy subjects. No difference was found in the allelic distribution of either polymorphisms. We therefore found no evidence that MMP-9 is a marker of susceptibility for AAA.

Endothelial progenitor cells induction by short-term stimulation with phytohaemagglutinin of mononuclear cells.

BACKGROUND: The identification of circulating endothelial progenitors cells (EPCs) in the adult has forced to reconsider how new blood vessels grow in physiological and pathological conditions. Neovascularization during adult life has long been attributed to angiogenesis only. However, recent studies have revealed that peripheral blood EPCs may be recruited and incorporated into sites of active neovascularization. PURPOSE: To verify that EPCs are induced from peripheral blood mononuclear cells (PBMCs) and bone marrow derived mononuclear cells (BMMCs) upon short-term stimulation with phytohaemoagglutinin (PHA), a potent T-cell mitogen. METHODS: PBMCs and BMMCs were isolated from healthy donors. Freshly isolated or depleted of adherent cells (one day and three days of adherence) mononuclear cells (MCs) were cultured in RPMI, 10% FBS, containing PHA (10 microl/10(6) cells) for 24 h. After stimulation with PHA, clusters of adherent cells were further propagated in M199 containing L-glutammine, Hepes, 20% FBS, heparin, antibiotics and bovine retina extract for 1 and 2 weeks. PBMCs and BMMCs cultured without PHA stimulation served as controls. FACS of EPCs was performed on attached cells after 7 and 14 days of culture. RESULTS AND CONCLUSION: After stimulation of MCs with PHA for 24 h, many cells clusters were observed and around these clusters some adherent EC-like cells were observed. These cells were ovoid but a very little of these were elongated in morphology, however their number and size gradually increased during culture. However a longer time was needed for obtaining EPCs from MCs harvested after adherence. Thus this indicates that short-term signals provided by PHA must be sufficient for MCs to express the ligands necessary for the induction of EPCs but signals from monocytes/macrophages are important for a more rapid differentiation.

Different growth conditions for peripheral blood endothelial progenitors.

PURPOSE: To compare different growth conditions for endothelial progenitor cells (EPCs) from peripheral blood mononuclear cells (PBMNCs). METHODS AND MATERIALS: PBMNCs of healthy volunteers were cultured on fibronectin as follows: M199 with VEGF, bFGF, IGF-I; the same medium with bovine retina-derived extract (RDE); freshly isolated or depleted of adherent cells PBMNCs in HUVEC conditioned medium; DiI-stained PBMNCs with HUVECs (1:4 ratio) in Ml99 with RDE. PBMNCs were analysed by FACS using mAbs for endothelial markers. EPCs migration was determined using a modified Boyden chamber assay and VEGF as chemoattractant. EPCs were seeded alone or with HUVECs on Matrigel to assess in vitro angiogenesis. RESULTS: With growth factors, numerous cell clusters appeared within 1 week. Spindle-shaped and attached cells sprouted, differentiating in endothelial cell (EC)-like cells within 2 weeks and forming cobblestone-like monolayers within 3 weeks. With RDE, numerous large cell clusters appeared within 1 week, but the number of cells with an EC morphology decreased during culture. FACS confirmed the endothelial phenotype and attached cells were able to migrate in response to VEGF. When nonadherent cells were cultured in HUVEC conditioned medium, they proliferated readily and EPCs were induced while freshly isolated cells neither proliferated nor induced EPCs. FACS analysis of the cocultures showed the presence of double-labeled PBMNCs expressing endothelial antigens. Capillary-like structures were observed on Matrigel only from cocultures and PBMNCs were able to incorporate in these networks. CONCLUSIONS: PBMNCs are able to differentiate in EPCs when stimulated with appropriate culture conditions (growth factors, HUVEC conditioned medium, HUVECs).