Mechanical ventilation and volutrauma: study in vivo of a healthy pig model

Mechanical ventilation is essential in intensive care units. However, it may itself induce lung injury. Current studies are based on rodents, using exceptionally large tidal volumes for very short periods, often after a "priming" pulmonary insult. Our study deepens a clinically relevant large animal model, closely resembling human physiology and the ventilator setting used in clinic settings. Our aim was to evaluate the pathophysiological mechanisms involved in alveolo/capillary barrier damage due to mechanical stress in healthy subjects. We randomly divided 18 pigs (sedated with medetomidine/tiletamine-zolazepam and anesthetised with thiopental sodium) into three groups (n=6): two were mechanically ventilated (tidal volume of 8 or 20 ml/kg), the third breathed spontaneously for 4 hours, then animals were sacrifi ced (thiopental overdose). We analyzed every 30' hemogasanalysis and the main circulatory and respiratory parameters. Matrix gelatinase expression was evaluated on bronchoalveolar lavage fl uid after surgery and before euthanasia. On autoptic samples we performed zymographic analysis of lung, kidney and liver tissues and histological examination of lung. Results evidenced that high V T evoked profound alterations of lung mechanics and structure, although low V T strategy was not devoid of side effects, too. Unexpectedly, also animals that were spontaneously breathing showed a worsening of the respiratory functions

Pre-odontoblast proliferation induced by near-infrared laser stimulation

OBJECTIVE: Laser therapy is known to stimulate cell proliferation and differentiation, an effect called "biostimulation". Although many clinical applications of laser therapy take advantage from such positive effect, the underlying molecular mechanisms are not fully understood. The aim of this work was to investigate the effect of near-infrared laser stimulation on rat pre-odontoblast cells (MDPC-23 cells) and the molecular mechanism/s involved. MATERIALS AND METHODS: MDPC-23 cells were stimulated with a near-infrared (980 nm) laser source with different energy settings (1-50 J, corresponding to 0.65-32.47 J/cm2) and cell proliferation was evaluated by manual count. ERK 1/2 pathway activation was evaluated by Western blot analysis. RESULTS: 1-10 J stimulation (corresponding to 0.65-6.5 J/cm2) significantly increase MDPC-23 cell proliferation and such effect seems to be mediated by ERK 1/2 signalling pathway activation, showing a key role of ERK 1/2 pathway in mediating the proliferative response induced by laser stimulation. CONCLUSIONS: Near infrared laser stimulation with low energies (1-10 J) is able to increase cell proliferation through ERK 1/2 signalling pathway activation. At the same time, higher energy stimulation (25-50 J) induces an initial toxic effect, probably activating pro-apoptotic signalling molecules, downstream ERK 1/2 kinase. Such results foster the application of this therapeutic approach in different clinical settings in which a regenerative tissue response is needed

Epiregulin-loaded PLGA nanoparticles increase human keratinocytes proliferation: preliminary data

OBJECTIVE:Epiregulin is a member of the epidermal growth factor (EGF) family produced by keratinocytes: the aim of this study was to investigate the ability of biocompatible nanoparticles loaded with such growth factor to increase human keratinocytes proliferation. MATERIALS AND METHODS:Different PLGA (Poly-d,l-lactide-co-glycolide)-nanoparticles (NPs) formulations have been characterized in size and zeta potential by dynamic light scattering (DLS) analysis. The ability of the different PLGA-NPs formulations to adhere onto dental surfaces has been tested, and epiregulin-enriched PLGA-NPs has been produced. Epiregulin release from NPs has been tested by enzyme-linked immunosorbent (ELISA) assay and the proliferative effects of epiregulin-NPs on human keratinocytes have been evaluated. RESULTS:DLS analysis revealed a different size distribution depending on the PLA/PGA (poly lactic acid/poly glycolic acid) ratio used. 50:50 PLGA-NPs exhibited the smaller size and the best dental adhesive ability. Moreover, such epiregulin-loaded NPs was able to increase cell proliferation. CONCLUSIONS:Direct dental pocket drug delivery implies the NPs solution loading onto the dental surface at the cement-enamel junction level: 50:50 PLGA-NPs, with their small size and excellent adhesive ability, represent an interesting tool to deliver epiregulin directly where there is the need for epithelial proliferation. These results describe a possible strategy for periodontal pocket delivery of Epiregulin-loaded PLGA-NPs and might provide a new approach for the treatment of gingival recession, where gingival epithelium proliferation is needed

Epiregulin induced human neuroblastoma cells differentiation through ERK1/2 signaling pathway

Neuroblastoma is one of the most frequent undifferentiated childhood extracranial solid tumor, arising from neural crest primitive neuroepithelial cells [1]. Epidermal growth factor (EGF) has been described as a modulator of neuroblastoma cells behavior [2]. The newest EGF family member, Epiregulin (Epi) is characterized by the broadest ErbB binding specificity and it is known to be a more potent stimulating factor than EGF alone [3]. SK-N-BE human neuroblastoma cell line was used in order to observe the effect of Epi on neuroblastoma cell proliferation and differentiation. After 72 h treatment, Epi (50-1000 ng/ml) reduced SK-N-BE cells proliferation and induced their differentiation towards a neuronal-like phenotype. Morphological differentiation has been confirmed by the increased expression of matrix metalloprotease 9 (MMP-9), a differentiation marker for SK-N-BE cells [4]. Moreover Epi induced ERK1/2 phosphorilation in SK-N-BE and the presence of U0126 (10 μM, ERK1/2 inhibitor) completely abolished Epi-induced differentiation, while PD98059 (5 μM, MAPK/ERK1 inhibitor) only reduced it. These data suggest a potential use of Epi as a therapeutic tool for neuroblastoma treatment

1α,25-Dihydroxycholecalciferol (Vitamin D3) induces NO-dependent endothelial cell proliferation and migration in a three-dimensional matrix.

Background/Aims: The 1α,25-dihydroxycholecalciferol (Vit. D) induces eNOS dependent nitric oxide (NO) production in human umbilical vein endothelial cells (HUVEC). To our knowledge, there are no reports directly relating Vit. D induced NO production to proliferation and/or migration in endothelial cells (EC). The aim of this study was to evaluate whether Vit. D addition to porcine EC could affect their proliferation and/or migration in a three-dimensional matrix via NO production. Materials and Methods: Porcine aortic endothelial cells (PAE) were used to evaluate Vit. D effects on cell proliferation and migration in a three-dimensional matrix. Results: Vit. D induced NO production in PAE cells. Moreover, it induced a significant increase in cellular proliferation and migration in a three-dimensional matrix. These effects were NO dependent, as inhibiting eNOS activity by L-NAME PAE migration was abrogated. This effect was strictly related to MMP-2 expression and apparently dependent on Vit. D and NO production. Conclusions: Vit. D can promote both endothelial cells proliferation and migration in a three-dimensional matrix via NO-dependent mechanisms. These findings cast new light on the role of Vit. D in the angiogenic process, suggesting new applications for Vit. D in such fields as tissue repair and wound healing

Down-regulation of the Lamin A/C in neuroblastoma triggers the expansion of tumor initiating cells

Tumor-initiating cells constitute a population within a tumor mass that shares properties with normal stem cells and is considered responsible for therapy failure in many cancers. We have previously demonstrated that knockdown of the nuclear envelope component Lamin A/C in human neuroblastoma cells inhibits retinoic acid-mediated differentiation and results in a more aggressive phenotype. In addition, Lamin A/C is often lost in advanced tumors and changes in the nuclear envelope composition occur during tumor progression. Based on our previous data and considering that Lamin A/C is expressed in differentiated tissues, we hypothesize that the lack of Lamin A/C could predispose cells toward a stem-like phenotype, thus influencing the development of tumor-initiating cells in neuroblastoma. This paper demonstrates that knockdown of Lamin A/C triggers the development of a tumor-initiating cell population with self-renewing features in human neuroblastoma cells. We also demonstrates that the development of TICs is due to an increased expression of MYCN gene and that in neuroblastoma exists an inverse relationship between LMNA and MYCN expression

Baseline Plasma Gas6 Protein Elevation Predicts Adverse Outcomes in Hospitalized COVID-19 Patients

: Reliable biomarkers allowing early patients' stratification for the risk of adverse outcomes in COVID-19 are lacking. Gas6, together with its tyrosine kinase receptors named TAM, is involved in the regulation of immune homeostasis, fibrosis, and thrombosis. Our aim was to evaluate whether Gas6, sAxl, and sMerTK could represent early predictors of disease evolution either towards a negative (death or need of ICU admission) or a positive (discharge and/or clinical resolution within the first 14 days of hospitalization) outcome. To this purpose, between January and May 2021 (corresponding to third pandemic wave in Italy), 139 consecutive SARS-CoV-2 positive patients were enrolled in a prospective observational study. Plasma levels of these molecules were measured by ELISA at the time of hospitalization and after 7 and 14 days. We observed that higher plasma Gas6 concentrations at hospital admission were associated with a worsening in clinical conditions while lower sMerTK concentrations at baseline and after 7 days of hospitalization were associated with a more favorable outcome. At multivariate analysis, after correction for demographic and COVID-19 severity variables (NEWS2 and PiO2/FiO2), only Gas6 measured at baseline predicted an adverse prognosis with an odds ratio of 1.03 (C.I. 1.01-10.5). At ROC curve analysis, baseline Gas6 levels higher than 58.0 ng/ml predicted a severe disease evolution with 53.3% sensitivity and 77.6% specificity (area under the curve 0.653, p = 0.01, likelihood ratio of 2.38, IQR: 1.46-3.87). Taken together, these results support the hypothesis that a dysregulation in the Gas6/TAM axis could play a relevant role in modulating the course of COVID-19 and suggest that plasma Gas6 may represent a promising prognostic laboratory parameter for this condition

Baseline Plasma Osteopontin Protein Elevation Predicts Adverse Outcomes in Hospitalized COVID-19 Patients

More than three years have passed since the first case, and COVID-19 is still a health concern, with several open issues such as the lack of reliable predictors of a patient's outcome. Osteopontin (OPN) is involved in inflammatory response to infection and in thrombosis driven by chronic inflammation, thus being a potential biomarker for COVID-19. The aim of the study was to evaluate OPN for predicting negative (death or need of ICU admission) or positive (discharge and/or clinical resolution within the first 14 days of hospitalization) outcome. We enrolled 133 hospitalized, moderate-to-severe COVID-19 patients in a prospective observational study between January and May 2021. Circulating OPN levels were measured by ELISA at admission and at day 7. The results showed a significant correlation between higher plasma concentrations of OPN at hospital admission and a worsening clinical condition. At multivariate analysis, after correction for demographic (age and gender) and variables of disease severity (NEWS2 and PiO2/FiO2), OPN measured at baseline predicted an adverse prognosis with an odds ratio of 1.01 (C.I. 1.0-1.01). At ROC curve analysis, baseline OPN levels higher than 437 ng/mL predicted a severe disease evolution with 53% sensitivity and 83% specificity (area under the curve 0.649, p = 0.011, likelihood ratio of 1.76, (95% confidence interval (CI): 1.35-2.28)). Our data show that OPN levels determined at the admission to hospital wards might represent a promising biomarker for early stratification of patients' COVID-19 severity. Taken together, these results highlight the involvement of OPN in COVID-19 evolution, especially in dysregulated immune response conditions, and the possible use of OPN measurements as a prognostic tool in COVID-19

Vitamin E modifies poly(D,L)lactic acid wettability and reduces bacterial adhesion

Highly biocompatible polylactic acid (PLA)-derived polymers are used for different biomedical applications such as orthopaedic screws and drug delivery devices. Nevertheless their clinical use is limited by their proinflammatory characteristics. Vitamin E (α-tocopherol, Vit. E), a natural antioxidant and anti-inflammatory agent has been used to improve different biomaterials biostability [1], and among them also P(D,L)LA [2]. In this work, addition of Vit.E (10-40% w/v) to P(D,L)LA films obtained by solvent casting technique increased polymer surface wettability and human plasma protein adsorption, while addition of Vit.E acetate (Vit.E Ac, 10-40% w/v), the acetic ester of α-tocopherol, often used as an alternative to Vit.E itself, failed in modifying polymer wettability. On the other hand, bacterial adhesion experiments onto control, Vit.E and Vit.E Ac enriched P(D,L)LA films showed that both presence of Vit.E and Vit.E Ac was able to reduce the adhesion of the RP62A Staphylococcus epidermidis strain [3]. In particular, in PLA + Vit. E samples the decrease in bacterial adhesion was of 56%, while, in the case of PLA + Vit. E Ac samples the decrease was of 40%. These preliminary data suggest that Vit. E addition to PLA containing medical devices could improve their resistance to bacterial infections