The profibrotic effects of chronic microaspiration of bile acids on lungs of rats at different stages.

This study aimed to explore the profibrotic effects of chronic microaspiration of two major bile acids, including chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA), on lungs of rats at different stages, as well as the underlying mechanisms in vivo. A rat model was induced by weekly intratracheal instillation of DCA and CDCA. Our results showed that chronic microaspiration of bile acids resulted in alveolar structure disorder, and inflammatory cells infiltration in the pulmonary interstitium at the early stage. Subsequently, numerous fibroblasts were proliferated, and collagen deposition was profoundly increased over the interstitium of the airways and vessels. Compared with control group, the expression of α-smooth muscle actin, type I collagen, hydroxyproline, transforming growth factor-ß1 (TGF-ß1), and matrix metalloproteinase-9 in the lung tissues were remarkably elevated at the 2nd week, reached the highest level at the 6th week, and maintained high at the 8th week in both DCA- and CDCA-treated groups (P < 0.05). Furthermore, chronic microaspiration of bile acids led to higher levels of glutathione and malondialdehyde, while lower level of superoxide dismutase in lung tissues compared with controls (P < 0.05), thereby resulting in the oxidant/antioxidant enzyme imbalance in the formation of fibrosis. In addition, we also found a consistent growth in the expression of farnesoid X receptor (FXR) in both DCA- and CDCA-treated groups. Our findings suggested that chronic microaspiration of bile acids could initiate the process of pulmonary fibrosis from the early phase and promote its progression in a time-dependent manner, which likely involved the TGF-ß1, oxidative stress, and FXR-related pathways.

Histopathological Findings Associated With Gastroesophageal Reflux Disease and Aspiration After Lung Transplantation: Initial Brazilian Single-Center Experience.

BACKGROUND: Gastro-esophageal reflux disease (GERD) and broncho-aspiration (BA) are known to increase the risk for chronic lung allograft dysfunction (CLAD). However, specific lung injury mechanisms are not clearly known. The objective of the study was to describe histopathological findings in surveillance lung transbronchial biopsies that can be correlated with episodes of BA in the lung allograft. METHODS: This retrospective analysis of surveillance transbronchial biopsies was performed in lung transplant recipients, with available data of broncho-alveolar fluid (cultures and cytology), lung function parameters, and esophageal functional tests. RESULTS: Were analyzed 11 patients, divided into 3 groups: (1) GERD group: 4 patients with GERD and CLAD diagnosis; (2) control group: 2 patients without GERD or CLAD; and (3) BA group: 5 patients with foreign material in lung biopsies. A histopathological pattern of neutrophilic bronchitis (NB) was present in 4 of 4 cases in the GERD group and in 1 of 5 cases in the BA group in 2 or more biopsy samples; culture samples were all negative; the 5 NB-positive patients developed CLAD and died (3/5) or needed re-transplantation (2/5). The other 3 patients in the BA group had GERD without NB or CLAD. Both patients in the control group had transient NB in biopsies with positive cultures but remained free of CLAD. CONCLUSIONS: Surveillance transbronchial biopsies may provide useful information other than the evaluation of acute cellular rejection and can help to identify high-risk patients for allograft dysfunction related to gastro-esophageal reflux.

Could prominent airway-centered fibroblast foci in lung biopsies predict underlying chronic microaspiration in idiopathic pulmonary fibrosis patients?

Chronic occult aspiration of small droplets (microaspiration) due to gastroesophageal reflux disease (GERD) and/or hiatal hernia is postulated to be a contributing factor in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Usual interstitial pneumonia (UIP) is the histopathologic correlate of IPF. We hypothesized that chronic microaspiration may manifest as prominent airway-centered fibroblastic foci (FFs) in IPF. UIP cases diagnosed by wedge biopsies over a 6-year period (2006-2011) were identified and scored (1-3) for the prominence of airway-centered FFs by 2 authors blinded for clinical history. Relevant clinical information was obtained. Thirty-seven patients (22 men) were diagnosed with IPF by multidisciplinary approach. Thirteen cases (35.1%) demonstrated high airway-centered FF score (score 3). Twenty (54.1%) patients carried a clinical diagnosis of GERD, and 3 patients (8.1%) had hiatal hernia. High airway-centered FF score was significantly associated with hiatal hernia diagnosis (P=.037) but not with a diagnosis of GERD or the use of proton pump inhibitors/histamine-2 receptor antagonists. High airway-centered FF score was associated with airway-centered acute inflammation (P=.028) and peribronchiolar granulomas (P=.042). In summary, IPF cases with hiatal hernia were more likely to have a prominent airway-centered FF. Given the strong association between hiatal hernia and GERD and their risk for developing chronic microaspiration, the prominent airway-centered FF in UIP might predict the presence of chronic microaspiration, acknowledging that GERD and proton pump inhibitor/histamine-2 receptor antagonist use failed to demonstrate a significant association. Larger studies are warranted for further investigation.

Modelo de instilación intra-traqueal de jugo gástrico en la rata: curso temporal de las alteraciones histológicas / Intra-tracheal instillation of gastric juice in the rat: time course of histological changes

Introduction: Aspiration of gastric content is associated with a wide range of clinical conditions (acute lung injury, severe interstitial pneumonia or bronchiolitis obliterans following lung transplantation). Objective: To study the course of histological alterations in a model of intra-tracheal instillation of gastric juice in rats. Methods: Anesthetized rats were euthanized at different times: 4, 12 and 24 hours and 4 and 7 days after intratacheal (IT) instillation of gastric juice. Animals that were not intervened served as controls. The right inferior lobe was studied (H-E) and a histological injury score was given according to a recently published score system. Results: Between 4-24 h an inflammatory-hemorragic pattern with bronchiol-centric distribution was characterized by a large proportion of neutrophils in both alveoli and interstitium, alveolarfluid accumulation, proteinaceous material andfew hyaline membranes. Between 4 and 7 days, mononuclear cells were more prevalent, the hemorrhagic component disappeared, the percentage of abnormal bronchioles was significantly reduced and there was organization of the alveolar infiltrate, with Masson bodies, granulomas and giant cells associated with gastric juice particles. Conclusions: In rats, IT instillation of gastric juice induces diffuse alveolar damage that evolves towards an early granulomatous interstitial pneumonia along with lax fibrous tissue. Knowledge of the temporary course of the pulmonary responses helps to the understanding of the consequences of the several clinical conditions that favor gastric content aspiration.

Introducción: La aspiración de contenido gástrico se asocia con diversas condiciones clínicas (daño pulmonar agudo, neumonía intersticial severa o bronquiolitis obliterante post-trasplante). Objetivo: Estudiar el curso de las alteraciones histológicas en un modelo de instilación intra-traqueal (IT)de jugo gástrico en ratas. Métodos: Ratas anestesiadas recibieron vía ITjugo gástrico de un pool obtenido previamente. Los animales fueron sacrificados a las: 4, 12 y 24 h y 4 y 7 días post-instilación. Animales sin intervención sirvieron como controles. El lóbulo inferior derecho fue estudiado (H-E) para la asignación de un puntaje de daño histológico de acuerdo a un sistema de puntuación recientemente publicado. Resultados: Entre 4-24 h se observó un patrón inflamatorio-hemorrágico de distribución bronquíolo-céntrica, con predominio de neutrófilos intersticiales y alveolares, edema, material proteináceo alveolar y escasas membranas hialinas. Entre los 4 y 7 días, se observó predominio mononuclear y desaparición del componente hemorrágico, se redujo significativamente el porcentaje de bronquíolos afectados y se observó organización del infiltrado inflamatorio, con cuerpos de Masson, granulomas y células gigantes asociadas a partículas del jugo gástrico. Conclusiones: En ratas, la instilación IT de jugo gástrico induce daño alveolar difuso que progresa hacia una neumonía intersticial granulo-matosa temprana con tejido fibroso laxo. El conocimiento del curso de la respuesta pulmonar en este modelo, contribuye a comprender las posibles consecuencias de las condiciones clínicas que favorecen la aspiración de contenido gástrico.

[The determination of stomach contents left on the material objects and in the environment].

The objective of the present experimental study was to develop the qualitatively new method for the determination of stomach contents left on the material objects and in the environment with special reference to the cases of aspiration asphyxia. We proposed the original approach for the determination of the origin of the traces of stomach contents based on the detection of pepsin, an enzyme that digests in the acidic milieu protein substances, such as gelatin (hydrolyzed collagen), a component of the emulsion layer of X-ray and photographic films. Samples of the stomach contents were taken from a corpse and placed on the surface of various materials that did not absorb moisture or repulsed it. In addition, materials undergoing putrefactive decomposition were investigated. Moreover, stains left by the cadaveric lung sections from the subjects who allegedly died from aspiration asphyxia on the emulsion layers were studied. A specially developed method was employed to detect pepsin, the main enzyme of the gastric juice. The majority of the studied samples including the control ones exhibited pepsin activity. The results of the study suggest the possibility of application of the proposed method for the detection of stomach contents on the environmental objects provided the material being studied avoided putrefactive modification.

Gastro-oesophageal reflux and gastric aspiration in idiopathic pulmonary fibrosis patients.

The aim of the study was to characterise gastro-oesophageal reflux (GOR) in idiopathic pulmonary fibrosis (IPF). 40 consecutive IPF patients underwent pulmonary high-resolution computed tomography (HRCT) scan and impedance-pH monitoring while off antisecretory therapy. The presence of pulmonary fibrosis was assessed using validated HRCT scores. Reflux features included distal oesophageal acid exposure, number of acid/weakly acidic reflux episodes and their proximal migration. 40 consecutive patients with interstitial lung disease other than IPF (non-IPF patients) and 50 healthy volunteers were also enrolled. IPF patients had significantly higher (p<0.01) oesophageal acid exposure (median (interquartile range (IQR)) 9.25 (4.7-15.4)% versus 3.3 (1.4-7.4)% versus 0.7 (0.2-4.2)%, number of acid (median (IQR) 45 (23-55) versus 32 (19-44) versus 18 (10-31)), weakly acidic (median (IQR) 34 (19-43) versus 21 (11-33) versus 18 (15-28)) and proximal reflux (median (IQR) 51 (26.5-65.5) versus 20 (9.5-34.5) versus 9 (5-20)) events compared to non-IPF patients and healthy volunteers, respectively. Pulmonary fibrosis HRCT scores correlated well with reflux episodes in both the distal (r(2)=0.567) and proximal (r(2)=0.6323) oesophagus. Patients with IPF had more bile acids and pepsin (p<0.03) in bronchoalveolar lavage fluid (BALF) (62% and 67%, respectively) and saliva (61% and 68%, respectively) than non-IPF patients (25% and 25% in BALF, and 33% and 36%, respectively, in saliva) and controls (0% and 0% in BALF and saliva, respectively). Acid GOR is common in IPF, but weakly acidic GOR may also occur. Patients with IPF had a risk of pulmonary aspiration of gastric contents. Outcome studies with intense antireflux therapy are needed.

Sudden death in Leigh syndrome: an autopsy case.

The present report describes the sudden death of a 3-year-old female child who had been clinically diagnosed with Leigh syndrome.Leigh syndrome is a heterogeneous progressive neurodegenerative disorder, which is characterized by focal or bilateral lesions in the thalamus, basal ganglia, brainstem, cerebellum, and spinal cord. Affected patients exhibit a variable clinical picture that frequently includes psychomotor retardation or regression, recurrent episodes of vomiting, failure to thrive, and signs of brainstem and basal ganglia dysfunction.The child was found dead in bed. Autopsy described the presence of symmetrical, necrotizing lesions scattered within the basal ganglia, thalamus, diencephalon, brainstem, and spinal-cord gray matter and revealed the presence of gastric contents in the upper and lower airways. We report the results of genetic investigations and describe the histological and immunohistochemical features that confirmed the diagnosis. These findings suggest that Leigh syndrome should be regarded as predisposing children to sudden death, especially by asphyxia secondary to the neurological disorder.

An assessment of the usefulness of routine histological examination in hanging deaths.

A retrospective study was carried out on 100 randomly selected medico-legal autopsies of victims who had committed suicide by hanging. All cases had undergone full police and coronial investigation. Complete external and internal examinations had been carried out including routine histological examination of organs. The age range of victims was 15-94 years (average, 41.7 years) with a male-to-female ratio of 7:1. External and internal injuries were consistent with the reported events. Diagnoses based purely on histology included hepatic steatosis (n = 16), asthma (n = 3), lymphocytic thyroiditis (n = 2), and pulmonary and cardiac sarcoidosis (n = 1). A large cell carcinoma of the lung and a rectal adenocarcinoma were confirmed. Histological evaluation was, however, of limited usefulness in contributing to the medico-legal evaluation of cases, with careful scene, external and internal examinations providing the most relevant information. The results of histological examination of tissues were all incidental to the cause, mechanism, and manner of death.