To favor bone reconstitution with biomaterials endothelial cells should maintain proper functions to drive angiogenesis. To this aim nanocrystals of hydroxyapatite (HA) have been synthesized and characterized on endothelial cells. Microvascular endothelial cells have been exposed to stoichiometric HA nanocrystals. Cell morphology and organization of cytoskeletal proteins have been monitored by SEM analysis and immunofluorescence. Biochemical markers of physiological and pathological responses of endothelial cells, endothelial constitutive nitric oxide synthase, and cycloxygenase-2 (ecNOS and COX-2, respectively) have been measured by immunofluorescence. Crystallized HA sustained endothelial survival without any cytotoxic effect. At the observation with SEM, endothelial cell morphology was maintained in the presence of HA. The localization and organization of beta-actin documented the formation of stress fibers, indicating an activation of endothelial cells induced by HA nanocrystals. Immunohistochemistry for biochemical key signaling pathways in endothelium demonstrated that nanocrystals of HA maintained the expression of ecNOS and did not increase COX-2 expression. In conclusion, the present findings indicate that HA nanocrystals exhibit high biocompatibility for microvascular endothelium. In the presence of HA nanocrystals endothelial cells maintain biochemical markers of healthy endothelium. They do not acquire a proinflammatory or thrombogenic phenotype, but express markers of functioning endothelium that might contribute to angiogenesis.

No abstract

The number of astronauts involved in longlasting missions and extra-vehicular activities is going to increase in the future. Consequently, the chance of injury due to traumatic events or unexpected emergency surgery will also increase and medical evacuation times to earth will be prolonged. Hence, the need to address requirements for surgery and trauma care in non terrestrial environments will be a priority. Tissue repair in weightlessness should therefore be regarded as a major issue not enough studied to date. Wound healing is a complex multi-step process, crucial to the survival of the organism. It starts with an inflammatory phase followed by a remodelling phase. During repair, the extracellular matrix (ECM) is sequentially remodelled by the concerted action of different cell types, in order to rebuild a functional tissue. The available literature concerning wound healing with mechanical unloading presents controversial results. However, many studies indicate impairment of the healing processes. Here we present a study on the behaviour of cells involved in the remodelling phase of repair, e.g. fibroblasts and endothelial cells, in response to microgravity (μg). In particular, their adhesion/migration, cytoskeleton organization, production of ECM molecules and receptors have been investigated. Cell response to pulsed Nd:YAG laser irradiation has also been investigated in order to evaluate the possibility to use laser irradiation for counteracting the effect of μg on wound healing. In μg, we observed alterations in production/assembling of ECM molecules. Increased fibronectin (FN) and laminin (LM) could be the cause for impaired ECM rebuilding and altered cell adhesion/migration. Treatment with Nd:YAG laser pulses induced organized fibrillogenesis and favoured endothelial cell spreading and monolayer formation. These findings open the way for a better understanding of tissue repair mechanisms in space and future clinical applications on earth.

No abstract

We evaluated the effects of urban air pollutants on human nasal mucosa over an 8-month period on 102 subjects living in Florence, Tuscany, Italy. A group of subjects living in a city with a lower level of pollution (Sassari, Sardinia, Italy) was also analyzed. Nasal mucosa cells were harvested by brushing, a noninvasive procedure. Half of the cells were used for genotoxicity studies using the alkaline comet assay, and half for morphological studies. The levels of DNA damage in the nasal mucosa were considerably higher (+73%) in the subjects living in Florence than in Sassari. High levels of atmospheric ozone in Florence air correlated with DNA damage, and to the prevalence of inflammatory pathologies of the upper respiratory tract, although the ozone concentrations were below the Italian recommended attention level. Furthermore, higher levels of DNA damage were correlated with a dysfunction in the ability to maintain a normal epithelial cell structure. These data suggest an association between ozone air levels and damage in the upper respiratory tract. It remains unclear whether ozone itself or other associated pollutants are responsible for the observed alterations.