Bronchopulmonary dysplasia (BPD) was first described in 1967 in a group of preterm infants as chronic inflammatory lung disease associated with arrested pulmonary development and supplemental oxygen needed. In humans is the earliest onset and probably the longest disease, and presents multifactorial origins. Nowadays, in preterm newborns the gold standard diagnostic methods for evaluating predisposition to develop BPD is airway lavage and tracheal aspirate, and less invasive for assessing immunological settings and biomarkers, is blood sample. Recently, non-invasive method based on cooling and condensing of exhaled breath condensate (EBC) containing several classes of compounds and biomarkers was proposed. Numerous researches demonstrate that in EBC high levels of leptin, a pro-inflammatory marker involved in lung injury, are associated with chronic lung disease such as asthma and COPD, but BPD was never evaluated. In the present study we assess EBC levels of leptin and its antagonist ghrelin, in preterm newborns mechanical ventilated, to identify the correlation with BPD development. Only few studies performed EBC on intubated preterm newborns to identify others markers of lung injury. EBC collection in first day of life showed no leptin and ghrelin concentration neither in BPD and nor in control group. Significant difference (p=0.002) in gestational age of controls compared to BPD was found, and significant difference (p=0.005) in the body weight of control group compared with BPD. An improved understanding of markers in BPD requires animal model, and the expression of leptin and ghrelin and their receptor were assessed in lung tissue of murine model of BPD obtained exposing newborns Wistar rats at high oxygen concentration for 14 days (PN 14), and to achieve severe BPD, prolonging the exposition for 28 days (PN28). PN14 and PN28 exposition showed a suffering look: shaggy hair, and general growth slowed if related with healthy controls. Architectural changes at PN14 confirms impaired alveolar lung development, and a reduction in the number and development of alveoli. Additionally, increased interstitial thickness, and epithelial cells with low cilia number, compared with control were found, and a continued exposure (PN28) showed an inflammatory and pulmonary edema increase. In pups statistically significant lowest values of body weight were found in BPD group at PN14 (p=0.002) and at PN28 (p=0.012) compared with controls in air room. Different dimensions of trachea were found in two groups of treatment at PN14: BPD presented high trachea caliber (p=0.008) if related to control. In lung tissue no significant changes expression of leptin and ghrelin and their receptors in control group and BPD group were observed for both exposure periods. In conclusion, it’s possible that leptin and ghrelin may not be predictive markers of lung injury: probably we have collected EBC too prior with respect the possible BPD development, but is essential to standardize EBC collection, with specific attention in hardware. Another explanation is that these markers are not involved in BPD lung injury as well as chronic lung disease such as asthma and COPD. Specific role and tissue expression of leptin and ghrelin remain to be clarify, for this reason is necessary to further investigate and focus the attention on metabolic issue with other approaches like proteomic and metabolomics, to better understand and identify this disease that nowadays presents high incidence.
La broncodisplasia (BPD) è una patologia cronica che colpisce i neonati pretermine e già dalla sua prima descrizione nel 1967, è stata associata ad un arresto dello sviluppo polmonare che necessita di ossigenoterapia. Il prelievo sanguigno risulta oggi giorno il metodo clinico meno invasivo per valutare il rischio di sviluppare BPD, tuttavia le metodiche di elezione prevedono il dosaggio di markers ottenuti attraverso procedure invasive quali l’aspirazione endotracheale ed il lavaggio bronchiale. Negli ultimi anni è stata posta particolare attenzione su una nuova metodica non invasiva che prevede la raccolta del condensato dell’aria esalata (EBC dall’acronimo Exhaled Breath Condensate). In un campione di EBC è possibile rilevare numerose molecole che permettono di valutare le condizioni respiratorie del soggetto. Tra i molteplici markers respiratori presenti, la leptina è un ormone recentemente associato a patologie croniche come l’asma e la BPCO, anche se tuttavia non è stata ancora indagata la possibile correlazione con la BPD. In questo studio sono stati raccolti, durante il primo giorno di vita, campioni di EBC in soggetti prematuri sottoposti a ventilazione meccanica per valutare i livelli di leptina e della sua antagonista metabolica, la grelina. Sono emerse differenze significative (p=0.002) nell’età gestazionale del gruppo di soggetti che hanno sviluppato BPD, rispetto ai soggetti controllo. Inoltre, è stato osservato come il peso corporeo alla nascita è nettamente superiore nei soggetti sani rispetto ai soggetti con BPD (p=0.005). Il dosaggio dei putativi markers nel campione di EBC non ha rivelato la presenza di leptina e di grelina, e questo esito potrebbe essere riconducibile al fatto che il campione sia stato raccolto troppo precocemente rispetto allo sviluppo della patologia. Un'altra supposizione prende in considerazione la mancanza di linee guida sulla corretta modalità di raccolta in pazienti intubati, causa di un probabile deterioramento del campione stesso. È stato quindi creato un modello animale di BPD esponendo ratti Wistar neonati ad alte concentrazioni di ossigeno per 14 e 28 giorni (rispettivamente PN14 e PN28). Al termine dell’esposizione sono stati prelevati i tessuti polmonari per una valutazione dell’espressione di leptina e grelina, ma anche in questo caso non sono emerse differenze significative nel gruppo BPD rispetto agli animali cresciuti in normossia, indipendentemente dalla durata dell’esposizione. Tuttavia sono state riscontrate sostanziali differenze nel peso e nello sviluppo dell’architettura bronchiale, con particolare sofferenza nel gruppo con BPD comparato con gli animali controllo dove è emerso un calibro tracheale nettamente superiore come segno di danno respiratorio. Questi risultati suggeriscono come probabilmente leptina grelina non siano direttamente coinvolte nel danno polmonare presente nella broncodisplasia, e pertanto non possono essere considerati dei marcatori precoci di patologia. Tuttavia, questo studio ha gettato le basi per ulteriori approfondimenti nell’ambito della standardizzazione della raccolta del campione di EBC per evidenziare i più idonei timepoint di campionamento, e preservare il possibile deterioramento del campione raccolto. Sarà comunque necessario approfondire il putativo ruolo di leptina e grelina, indagando anche sugli aspetti di metabolomica e proteomica, con l’obiettivo di analizzare il rischio di sviluppo di una patologia cronica che tutt’oggi presenta ancora un’elevata incidenza.
Levels of leptin and ghrelin in exhaled breath condensate (EBC) as potential markers of bronchopulmonary dysplasia in ventilated preterm newborns
PIAZZA, Michele
2017
Abstract
Bronchopulmonary dysplasia (BPD) was first described in 1967 in a group of preterm infants as chronic inflammatory lung disease associated with arrested pulmonary development and supplemental oxygen needed. In humans is the earliest onset and probably the longest disease, and presents multifactorial origins. Nowadays, in preterm newborns the gold standard diagnostic methods for evaluating predisposition to develop BPD is airway lavage and tracheal aspirate, and less invasive for assessing immunological settings and biomarkers, is blood sample. Recently, non-invasive method based on cooling and condensing of exhaled breath condensate (EBC) containing several classes of compounds and biomarkers was proposed. Numerous researches demonstrate that in EBC high levels of leptin, a pro-inflammatory marker involved in lung injury, are associated with chronic lung disease such as asthma and COPD, but BPD was never evaluated. In the present study we assess EBC levels of leptin and its antagonist ghrelin, in preterm newborns mechanical ventilated, to identify the correlation with BPD development. Only few studies performed EBC on intubated preterm newborns to identify others markers of lung injury. EBC collection in first day of life showed no leptin and ghrelin concentration neither in BPD and nor in control group. Significant difference (p=0.002) in gestational age of controls compared to BPD was found, and significant difference (p=0.005) in the body weight of control group compared with BPD. An improved understanding of markers in BPD requires animal model, and the expression of leptin and ghrelin and their receptor were assessed in lung tissue of murine model of BPD obtained exposing newborns Wistar rats at high oxygen concentration for 14 days (PN 14), and to achieve severe BPD, prolonging the exposition for 28 days (PN28). PN14 and PN28 exposition showed a suffering look: shaggy hair, and general growth slowed if related with healthy controls. Architectural changes at PN14 confirms impaired alveolar lung development, and a reduction in the number and development of alveoli. Additionally, increased interstitial thickness, and epithelial cells with low cilia number, compared with control were found, and a continued exposure (PN28) showed an inflammatory and pulmonary edema increase. In pups statistically significant lowest values of body weight were found in BPD group at PN14 (p=0.002) and at PN28 (p=0.012) compared with controls in air room. Different dimensions of trachea were found in two groups of treatment at PN14: BPD presented high trachea caliber (p=0.008) if related to control. In lung tissue no significant changes expression of leptin and ghrelin and their receptors in control group and BPD group were observed for both exposure periods. In conclusion, it’s possible that leptin and ghrelin may not be predictive markers of lung injury: probably we have collected EBC too prior with respect the possible BPD development, but is essential to standardize EBC collection, with specific attention in hardware. Another explanation is that these markers are not involved in BPD lung injury as well as chronic lung disease such as asthma and COPD. Specific role and tissue expression of leptin and ghrelin remain to be clarify, for this reason is necessary to further investigate and focus the attention on metabolic issue with other approaches like proteomic and metabolomics, to better understand and identify this disease that nowadays presents high incidence.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14242/113385
URN:NBN:IT:UNIVR-113385