New bioactive motifs and their use in functionalized self-assembling peptides for NSC differentiation and neural tissue engineering.

Developing functionalized biomaterials for enhancing transplanted cell engraftment in vivo and stimulating the regeneration of injured tissues requires a multi-disciplinary approach customized for the tissue to be regenerated. In particular, nervous tissue engineering may take a great advantage from the discovery of novel functional motifs fostering transplanted stem cell engraftment and nervous fiber regeneration. Using phage display technology we have discovered new peptide sequences that bind to murine neural stem cell (NSC)-derived neural precursor cells (NPCs), and promote their viability and differentiation in vitro when linked to LDLK12 self-assembling peptide (SAPeptide). We characterized the newly functionalized LDLK12 SAPeptides via atomic force microscopy, circular dichroism and rheology, obtaining nanostructured hydrogels that support human and murine NSC proliferation and differentiation in vitro. One functionalized SAPeptide (Ac-FAQ), showing the highest stem cell viability and neural differentiation in vitro, was finally tested in acute contusive spinal cord injury in rats, where it fostered nervous tissue regrowth and improved locomotor recovery. Interestingly, animals treated with the non-functionalized LDLK12 had an axon sprouting/regeneration intermediate between Ac-FAQ-treated animals and controls. These results suggest that hydrogels functionalized with phage-derived peptides may constitute promising biomimetic scaffolds for in vitro NSC differentiation, as well as regenerative therapy of the injured nervous system. Moreover, this multi-disciplinary approach can be used to customize SAPeptides for other specific tissue engineering applications.

[Biological monitoring of occupational exposure to acrylonitrile]. / Monitoraggio biologico delle esposizioni professionali ad acrilonitrile.

Acrylonitrile (ACN) is a solvent widely used in industry especially as raw material in the manufacturing of acrylic fibres, clothes and domestic furniture. It is also used in manufacturing of resins (ACN-butadiene-styrene...) and for production of nitrilic elastomers. Some researchers proposed the biological monitoring of occupational exposure to ACN by measuring the solvent in the urine, but results were widely spread especially in relation to the analytical method used. This article reports the main aspects that can reduce the variability of results. We checked several ACN solutions in water and urine after heating at 90 degrees C for 1, 3, 5, 8 and 16 hours. Water solutions maintained their ACN concentration in all the checked conditions, while urine concentrations of ACN in urine deceased during the conditioning time until 80% of their initial concentration. The analysis of ACN in urine provided by workers potentially exposed to ACN and by control subjects gave median results of 1.9 and 2.0 micrograms/g creat, without any statistical difference. The results split in relation to the smoking habit showed a statistic difference: the median values of ACN were 1.7 and 4.7 micrograms/g creat, respectively among the 175 non-smokers and 57 smokers.