Predittori di danno polmonare in fibrosi cistica: indagine su infezione e infiammazione

Background: Inflammation and infection are cornerstones in Cystic fibrosis (CF) lung disease. The research about a biomarker related to disease progression, tracking respiratory exacerbations and effectiveness of antibiotic therapy, is fervent. Aim: this PhD work aimed to investigate: -if plasma and exhaled breath condensate (EBC) levels of Asymmetric dimethilarginine (ADMA) and related metabolites, reportedly related to inflammation in asthma, could associate to disease history, especially respiratory exacerbation onset and effectiveness of treatment; -if lung MRI sequence diffusion weighted imaging (DWI), known to depict tissue inflammation, could discriminate between stable disease and exacerbation, and highlight treatment effectiveness; and if morphological MRI may be influenced by chronic colonization of the airways by P. aeruginosa; -if chronic colonization of the airways by P. aeruginosa may be characterized by an evolution in antibiotic resistance, especially in pediatric CF population; Methods: 4 studies were elaborated -a perspective study on pediatric CF patients, divided into stable and exacerbated patients; clinical data, EBC and plasma were collected in stable group at enrollment, and in exacerbated group before and after antibiotic treatment; ADMA and related metabolites were measured in plasma and EBC through Ultra performance liquidi cromatography, coupled with tandem mass spectrometry, and compared to healthy controls; -a perspective study on pediatric CF patients, in which EBC and clinical data were collected every month for 6 month or till exacerbation; ADMA and related metabolites were measured and correlation with clinical data was tested; -a perspective study on patients divided into stable and exacerbated; spirometry and RMN were performed in exacerbated patients before and after antibiotic treatment and in stable patients at enrollment and after 2 weeks; -a retrospective study about a 4-year period, based upon extraction of clinical and microbiologic data about antibiotic sensitivity of P.aeruginosa in CF patients chronically colonized by P.aeruginosa. Results: -an univocal marker of inflammation could not be identified in EBC; given the absence of differences in ADMA levels among patient groups and healthy controls, and the increase of Citrullin levels in CF compared with controls, a dysregulation of ADMA metabolism was suspected; -various metabolites were higher in plasma of CF patients than in controls; ADMA was increased in exacerbated patients before antibiotic treatment and decreased to levels similar to stable patients after antibiotic treatment; Aginine was increased in all groups, with a further increase after antibiotic treatment; -DWI tracked respiratory exacerbation and effectiveness of treatment; a good correlation to clinical and spirometric parameters was proved; inter and intra-observer agreement were very good; morphologic MRI showed correlation with spirometry and colonization of the airways by P. aeruginosa; -the prevalence of antibiotic sensitivity of P. aeruginosa showed an evolution during the 4-year study period; a decrease in sensitivity especially to fluoroquinolones was proved; sensitivity diminished to a greater extent in pediatic population; increased minimum inhibitory concentrations were found in pediatric patients who underwent more antibiotic courses per year. Conclusions: CF has great phenotipic variability among patients and many factors may influence airways conditions, so a marker can hardly describe this complexity. Moreover, inflammatory pathways alterations are still not completely understood, and deserve futher investigations, given our findings in EBC. Findings on plasma highlighted ADMA role and depicted systemic alterations of the disease. A novel method as metabolomics could enlighten different aspects of the disease in future and help in the stratification of patients. Thoracic MRI with DWI sequence has shown a promising role in inflammation localization and quantification and surely deserves further detailed studies as clinical and research outcome measure