Potentialities of LL37 for Wound Healing Applications: Study of Its Activity in Synergy with Biodegradable Composites Made of PVA and CA

Wound healing is a dynamic and complex process that results from the interaction between cytokines, growth factors, blood components and the extracellular matrix. Conventional dressings made of natural or synthetic materials have only the ability to manage the wound and protect it from repeated trauma. With the advancement of technology, wound dressings have evolved and are now capable of intervening in the healing process by targeting specific features of the wound, aside from protecting the wounded site. In this work, bioactive dressings capable of promoting healing and fighting infection in chronic wounds were explored. Various antimicrobial biomolecules were examined in light of their pathogen fighting skills and immunoregulatory potentialities. Dressing production processes were also investigated. Biodegradable composite dressings made of poly(vinyl alcohol), polycaprolactone, chitosan and cellulose blends were our main focus. The goal was to evaluate the synergistic effect of biomolecules and biodegradable polymeric dressings, considering the local and systemic treatment demands of chronic wounds.Portuguese Foundation for Science and Technology (FCT), FEDER funds by means of Competitive Factors Operational Program (POCI) for funding the projects POCI-01-0145-FEDER-028074 and UID/CTM/00264/201

Cellulose acetate in wound dressings formulations: potentialities and electrospinning capability

Série: IFMBE Proceedings, vol. 76Any open wound is a potential site for microorganisms’ invasion since their presence around us is inevitable. Skin wound healing relies on a series of complex physiochemical processes that remain a big challenge for healthcare professionals, particularly when the wounds are colonized by bacteria. Wound dressings play a major role in wound healing as they manage the wounded site, controlling the moisture balance and protecting the wound from repeated trauma, and by preventing possible infections from developing into more serious complications. Recently, bioactive dressings loaded with drugs and/or antimicrobial agents, allowing for a continuous and sustainable release of these molecules at the wounded site, have appeared in the market. Antimicrobial resistance is a growing health care problem, requiring more effective solutions than antibiotics. As such, nano- and microfibrous mats produced via electrospinning technique and loaded with natural-origin antimicrobial agents have attracted a lot of attention. Various polymers have been applied to engineer nanofibrous electrospun dressings. However, the environment impact of the synthesis and processing methods of synthetic polymers is undesirable. Therefore, the application of cellulose-derived materials (highly abundant polymer of natural-origin) becomes crucial as a green alternative to produce electrospun wound dressings with superior wettability, breathability and high capacity to promote cell proliferation, at relatively low costs. In this paper, different biomolecules loaded onto cellulose acetate (CA)-based polymeric nanofibers were investigated, and their antimicrobial properties were highlighted as alternatives to conventional antibiotics.Authors acknowledge the Portuguese Foundation for Science and Technology (FCT), FEDER funds by means of Competitive Factors Operational Program (POCI) for funding the projects POCI-01-0145-FEDER-028074 and UID/CTM/00264/2019

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Cerebral blood flow (CBF) increases from rest to ∼60% of peak oxygen uptake (VO(2peak)) and thereafter decreases towards baseline due to hyperventilation-induced hypocapnia and subsequent cerebral vasoconstriction. It is unknown what happens to CBF in older adults (OA), who experience a decline in CBF at rest coupled with a blunted ventilatory response during VO(2peak). In 14 OA (71 ± 10 year) and 21 young controls (YA; 23 ± 4 years), we hypothesized that OA would experience less hyperventilation-induced cerebral vasoconstriction and therefore an attenuated reduction in CBF at VO(2peak). Incremental exercise was performed on a cycle ergometer, whilst bilateral middle cerebral artery blood flow velocity (MCA V(mean); transcranial Doppler ultrasound), heart rate (HR; ECG) and end-tidal PCO(2) (P(ET)CO(2)) were monitored continuously. Blood pressure (BP) was monitored intermittently. From rest to 50% of VO(2peak), despite greater elevations in BP in OA, the change in MCA V(mean) was greater in YA compared to OA (28% vs. 15%, respectively; P < 0.0005). In the YA, at intensities >70% of VO(2peak), the hyperventilation-induced declines in both P(ET)CO(2) (14 mmHg (YA) vs. 4 mmHg (OA); P < 0.05) and MCA V(mean) (−21% (YA) vs. −7% (OA); P < 0.0005) were greater in YA compared to OA. Our findings show (1), from rest-to-mild intensity exercise (50% VO(2peak)), elevations in CBF are reduced in OA and (2) age-related declines in hyperventilation during maximal exercise result in less hypocapnic-induced cerebral vasoconstriction