The purpose of this study was to test the hypothesis that specific epicardial adipose tissue (EAT) proinflammatory adipokines might be implicated in acute coronary syndrome (ACS). We compared expression and protein secretion of several EAT adipokines of male ACS with those of matched stable coronary artery disease (CAD) patients and controls with angiographically normal coronary arteries. The effect of supernatant of cultured EAT on endothelial cell permeability in vitro was also evaluated in the three study groups. EAT of ACS patients showed significantly higher gene expression and protein secretion of resistin than patients with stable CAD. Interleukin-6, plasminogen activator inhibitor-1, and monocyte chemoattractant protein-1 genes were also significantly overexpressed in ACS compared with the control group but not when compared with stable CAD. Immunofluorescence of EAT sections revealed a significantly greater number of CD68⁺cells in ACS patients than stable CAD and control groups. The permeability of endothelial cells in vitro was significantly increased after exposure to supernatant of cultured EAT from ACS, but not control or stable CAD groups, and this effect was normalized by anti-resistin antiserum. We found that EAT of patients with ACS is characterized by increased expression and secretion of resistin and associated with increased in vitro endothelial cell permeability.

A growing body of evidence suggests that chromogranin A (CgA), a secretory protein released by many neuroendocrine cells and frequently used as a diagnostic and prognostic serum marker for a range of neuroendocrine tumors, is a precursor of several bioactive fragments. This work was undertaken to assess whether the N‐terminal fragment CgA _1–76 (called vasostatin I) can inhibit the proangiogenic activity of vascular endothelial growth factor (VEGF), a factor involved in tumor growth. The effect of recom‐binant human vasostatin I (VS‐1) on VEGF‐induced human umbilical endothelial cells (HUVEC) signaling, proliferation, migration, and organization has been investigated. We have found that VS‐1 (3 μg/ml;330 nM) can inhibit VEGF‐induced ERK phosphorylation, as well as cell migration, proliferation, morphogenesis, and invasion of collagen gels in various in vitro assays. In addition, VS‐1 could inhibit the formation of capillary‐like structures in Matrigel plugs in a rat model. VS‐1 could also inhibit basal ERK phosphorylation and motility of HUVEC, leading to a more quiescent state in the absence of VEGF, without inducing apoptotic or necrotic effects. Conclusion: These findings suggest that vasostatin I may play a novel role as a regulator of endothelial cell function and homeostasis.—Belloni, D., Scabini, S., Foglieni, C., Veschini, L., Giazzon, A., Colombo, B., Fulgenzi, A., Helle, K. B., Ferrero, M. E., Corti, A., Ferrero, E. The vasostatin‐I fragment of chromogranin A inhibits VEGF‐induced endothelial cell proliferation and migration. FASEB J. 21, 3052–3062 (2007)

Osteochondral defects remain a major clinical challenge mainly due to the combined damage to the articular cartilage and the underlying bone, and the interface between the two tissues having very different properties. Current treatment modalities have several limitations and drawbacks, with limited capacity of restoration; however, tissue engineering shows promise in improving the clinical outcomes of osteochondral defects. In this study, a novel gradient scaffold has been fabricated, implementing a gradient structure in the design to mimic the anatomical, biological and physicochemical properties of bone and cartilage as closely as possible. Compared with the commonly studied multi-layer scaffolds, the gradient scaffold has the potential to induce a smooth transition between cartilage and bone and avoid any instability at the interface, mimicking the natural structure of the osteochondral tissue. The scaffold comprises a collagen matrix with a gradient distribution of low-crystalline hydroxyapatite particles. Physicochemical analyses confirmed phase and chemical compositions of the gradient scaffold and the distribution of the mineral phase along the gradient scaffold. Mechanical tests confirmed the gradient of stiffness throughout the scaffold, according to its mineral content. The gradient scaffold exhibited good biological performances both in vitro and in vivo. Biological evaluation of the scaffold, in combination with human bone-marrow–derived mesenchymal stem cells, demonstrated that the gradient of composition and stiffness preferentially increased cell proliferation in different sub-regions of the scaffold, according to their high chondrogenic or osteogenic characteristics. The in vivo biocompatibility of the gradient scaffold was confirmed by its subcutaneous implantation in rats. The gradient scaffold was significantly colonised by host cells and minimal foreign body reaction was observed. The scaffold’s favourable chemical, physical and biological properties demonstrated that it has good potential as an engineered osteochondral analogue for the regeneration of damaged tissue.

Angiogenesis is a complex, orchestrated process that plays a critical role in several conditions and has special relevance in the progression of cancer. Hypoxia is the major stimulus for angiogenesis, and hypoxia-inducible transcription factor–1 alpha (HIF-1α) is its key mediator. We set up a novel in vitro model of HIF-1α up-regulation by treating human umbilical vein endothelial cells (HUVECs) with the hypoxia-mimicking deferoxamine (DFO) and found that this condition was sufficient to promote angiogenesis, like the well-known HUVEC model cultured under low pO_2. The proteasome inhibitor bortezomib, which induces strong apoptosis in cancer cells, abrogated proliferation and angiogenesis of HUVECs when used at a high concentration (100 nM), yet promoted both functions at a low dosage (10 nM). This double-edged effect appeared to be mediated by differential effects exerted by the different concentrations of bortezomib on 2 master regulators of tumor-associated angiogenesis, HIF-1α and nuclear factor kappa B (NF-kB). Significantly, when HUVECs were induced to express HIF-1α prior to bortezomib treatment, proliferative and angiogenic responses were abolished, and a greatly enhanced proapoptotic effect was promoted with both concentrations of the drug. These findings indicate that HIF-1α up-regulation may sensitize endothelial cells to the antiangiogenic and proapoptotic effects of bortezomib and might be exploited to target tumor-associated vessels in the course of antiangiogenic therapies.