Reduction of lipid-laden macrophage index after laparoscopic Nissen fundoplication in cystic fibrosis patients after lung transplantation

Surgical considerations in cystic fibrosis: what every general surgeon needs to know

Cystic fibrosis (CF) is a complex multiorgan disease, which often affects the gastrointestinal tract. With improved CF specific therapies and multidisciplinary management, patients with CF are now living longer with a median life expectancy of around 50 years. This increased life expectancy has resulted in corresponding increase in presentations of the CF patient with comorbid surgical conditions that were never important considerations. Investigations and management of these conditions, such as distal intestinal obstruction syndrome and colorectal cancer warrant good clinical understanding of the unique challenges that CF patients present including chronic immunosuppression, impaired respiratory function and their multi-organ dysfunction. The purpose of this review is to provide general surgeons with a contemporary update on the CF related surgical issues as they are likely to become increasingly involved in the care of these complex patients and form an integral part of the multidisciplinary team.

Laparoscopic surgery in patients with cystic fibrosis: A systematic review

INTRODUCTION

Laparoscopic surgery may be advantageous for cystic fibrosis (CF) patients because it leads to fewer complications than open surgery. However, it could still lead to pulmonary and cardiovascular complications in CF patients. We aimed to systematically review the use of laparoscopic surgery in CF patients.

METHODS

A systematic review was performed in compliance with PRISMA guidelines. A literature search was performed using PubMed/MEDLINE, ScienceDirect, EMBASE, and Google Scholar, with "cystic fibrosis and laparoscopic surgery" and "cystic fibrosis and minimally invasive surgery" used as the search terms. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria were applied. The protocol was registered with the PROSPERO register.

RESULTS

Six studies met the predetermined inclusion criteria; accordingly, two studies provided high-quality evidence and four provided moderate-quality evidence. The interrater correlation was convincing (r_s  = .95, P = .02, two-tailed). Therefore, three quantitative studies and three qualitative studies were assessed and evidence-graded in accordance with the GRADE protocol.

CONCLUSION

The benefits of laparoscopic surgical interventions for patients with CF were supported with good evidential value and recognized as a safe and suitable surgical option.

Effects of fermented Yupingfeng on intramuscular fatty acids and ruminal microbiota in Qingyuan black goats

Our previous work has demonstrated that Yupingfeng, a Chinese herb medicine, considered as prebiotic showed beneficial properties in poultry health and disease prevention and regulated intestinal microbiota. The effects of Yupingfeng on fatty acids related to meat flavor and ruminal microbiota are not yet known in Qingyuan black goat. In this study, we supplemented fermented (FYP) and unfermented (UYP) Yupingfeng in different combinations to 90 goats. Compared with the normal control group, FYP and UYP significantly increased the concentration of palmitic acid, octadecanoic acid, and arachidonate acid (related to meat flavor) in the longissimus dorsi muscle (p < .05). In addition, the significant upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid translocase (CD36) was observed in the FYP and UYP groups (p < .05). In addition, Firmicutes and Bacteroidetes were the most abundance in goat rumen. At the genus level, FYP and UYP significantly increased Ruminococcus related to fiber degradation, and Alistipes related to short-chain fatty acids production. In summary, Yupingfeng could improve fatty acids of goat meat, which is probably triggered by the increase of PPARγ and CD36, and microbial activity. Besides, FYP showed more beneficial effects than UYP, with increased flavor fatty acids and beneficial microbes.

Alveolar Macrophage ABCG1 Deficiency Promotes Pulmonary Granulomatous Inflammation

Pulmonary granuloma formation is a complex and poorly understood response to inhaled pathogens and particulate matter. To explore the mechanisms of pulmonary granuloma formation and maintenance, our laboratory has developed a multiwall carbon nanotube (MWCNT)-induced murine model of chronic granulomatous inflammation. We have demonstrated that the MWCNT model closely mimics pulmonary sarcoidosis pathophysiology, including the deficiency of alveolar macrophage ATP-binding cassette (ABC) lipid transporters ABCA1 and ABCG1. We hypothesized that deficiency of alveolar macrophage ABCA1 and ABCG1 would promote pulmonary granuloma formation and inflammation. To test this hypothesis, the effects of MWCNT instillation were evaluated in ABCA1, ABCG1, and ABCA1/ABCG1 myeloid-specific knockout (KO) mice. Histological examination revealed significantly larger pulmonary granulomas in ABCG1-KO and ABCA1/ABCG1 double-KO animals when compared with wild-type animals. Evaluation of BAL cells indicated increased expression of CCL2 and osteopontin, genes shown to be involved in the formation and maintenance of pulmonary granulomas. Single deficiency of alveolar macrophage ABCA1 did not affect MWCNT-induced granuloma formation or proinflammatory gene expression. These observations indicate that the deficiency of alveolar macrophage ABCG1 promotes pulmonary granulomatous inflammation and that this is augmented by additional deletion of ABCA1.

Gastroesophageal reflux in cystic fibrosis across the age spectrum

Background

Scientific advances have improved longevity in cystic fibrosis (CF) patients and many of these patients can expect to experience age-related gastrointestinal co-morbidities. We aimed to assess the extent to which age might impact gastroesophageal reflux (GER) in patients with CF.

Methods

Our esophageal pH-multichannel intraluminal impedance monitoring database was searched for tracings belonging to CF patients ≥2 years old without prior fundoplication and not taking anti-reflux medications immediately prior (within 7 days) and during the study. Tracings were retrospectively analyzed; Impedance and pH variables were evaluated with respect to age and pulmonary function.

Results

Twenty-eight patients were enrolled; 16 children (3.1-17.7 years) and 12 adults (18.2-48.9 years). Among pH probe parameters, correlation analysis showed DeMeester score (P=0.011) and number of acid reflux events lasting >5 minutes (P=0.047) to be significantly correlated with age. Age was not significantly correlated with any of the impedance parameters. Age was negatively correlated with baseline impedance (BI) in the distal esophagus (r=-0.424, P=0.023) and BI was negatively correlated with several pH parameters, including reflux index (r=-0.553, P=0.002), number of total acid reflux events (r=-0.576, P=0.001), number of acid reflux events lasting >5 minutes (r=-0.534, P=0.003), and DeMeester score (r=-0.510, P=0.006). Pulmonary function (percent predicted forced expiratory volume in one minute; ppFEV₁) was negatively correlated with age (r=-0.494, P=0.0007). The interaction of age and ppFEV₁ and any of the reflux parameters, however, was not significant (P>0.05); the strongest evidence for an interaction was found for the number of acid reflux events reaching the proximal esophagus, but this interaction still did not reach statistical significance (P=0.070).

Conclusions

In a small cohort, we found evidence that age may be associated with increased acid exposure and that both age and increased acid exposure are associated with reduced BI in the distal esophagus. The negative relationship between pulmonary function and age in our cohort is not related to GER. This pilot study supports the need for esophageal assessment and treatment of GER as standard components of clinical care for an aging CF population.

Lipid Uptake by Alveolar Macrophages Drives Fibrotic Responses to Silica Dust

Silicosis is a common occupational disease and represents a significant contributor to respiratory morbidity and mortality worldwide. Lipid-laden macrophages, or foam cells, are observed in the lungs of patients with silicosis but the mechanisms mediating their formation remain poorly understood. In this study, we sought to elucidate the mechanisms by which silica promotes foam cell formation in the lung, and to determine whether uptake of lipids alone is sufficient to drive TGF-β production by alveolar macrophages. Consistent with previous reports, we found that foam cells were markedly increased in the lungs of patients with silicosis and that these findings associated with both higher levels of intracellular lipid levels (oxidized LDL, ox-LDL) and elevated transcript levels for the lipid scavenger receptor CD36 and the nuclear receptor PPARγ. Employing a rat alveolar macrophage cell line, we found that exposure to silica dust or ox-LDL alone had a modest effect on the induction of foam cell formation and only silica was capable of inducing the production of TGF-β. In contrast, foam cell formation and TGF-β production were both dramatically increased when cells were exposed to a combination of silica dust and ox-LDL. Moreover, we found that these endpoints were markedly attenuated by either blocking CD36 or inhibiting the activity of PPARγ. Altogether, our findings suggest that foam cell formation and TGF-β production are driven by the simultaneous uptake of silica and lipids in alveolar macrophages and that strategies aimed at blocking lipid uptake by alveolar macrophages might be effective in ameliorating fibrotic responses to silica in the lung.

Cystic Fibrosis and gastroesophageal reflux disease

Gastroesophageal reflux is common in children and adults with cystic fibrosis (CF). Pathological gastroesophageal reflux disease (GERD) is also frequent in patients of all ages with CF. This article reviews the pathophysiology, diagnostic work-up, management options, complications, and future directions in the evaluation and management of GERD - unique to and pertinent for - patients with CF in particular.

The Role of Microaspiration in the Pathogenesis of Gastroesophageal Reflux-related Chronic Cough

Background/Aims

Gastroesophageal reflux disease (GERD) is one of the main causes of chronic cough. We evaluated the role of microaspiration in the pathogenesis of reflux-related cough by determining the amount of lipid-laden macrophages (LLMs) in bronchoalveolar lavage (BAL) specimens.

Methods

A total of 161 cases of chronic cough were evaluated, and 36 patients (average age 48.2 years) were recruited for this single center prospective study. Patients with a history of smoking, angiotensin converting enzyme inhibitor usage, any abnormality on pulmonary function tests, abnormal chest X-rays, occupational or environmental exposures, or upper airway cough syndrome were excluded. GERD was evaluated by 24-hour esophageal impedance-pH monitoring. BAL specimens for LLM determination were obtained from 34 patients by flexible bronchoscopy.

Results

Patients with pathological intra-esophageal reflux according to multichannel intraluminal impedance and pH monitoring had higher LLM positivity in BAL specimens than patients without pathological reflux (8/14 in reflux positive group vs 1/22 in reflux negative group; P = 0.004). The BAL cell distribution was not different between the 2 groups (P = 0.574 for macrophages, P = 0.348 for lymphocytes, P = 0.873 for neutrophils and P = 0.450 for eosinophils).

Conclusions

Our results confirm the role of the microaspiration of refluxate in the pathogenetic mechanism of chronic cough. While bronchoscopy is indicated in patients with chronic cough, in addition to the routine airway evaluation, BAL and LLM detection should be performed. LLM can be used to diagnose aspiration in reflux-related chronic cough. Future studies are needed to evaluate the response to anti-reflux medications or surgery in patients with LLM positivity.

Esophageal Dysmotility, Gastro-esophageal Reflux Disease, and Lung Transplantation: What Is the Evidence?

Lung transplantation is an effective and life-prolonging therapy for patients with advanced lung disease (ALD). However, long-term patient survival following lung transplantation is primarily limited by development of an inflammatory and fibrotic process involving the lung allograft known as bronchiolitis obliterans syndrome (BOS). Although the precise cause of BOS remains uncertain and is likely multifactorial, chronic aspiration of gastro-duodenal contents is one possible contributing factor. Multiple small, cross-sectional studies performed over the past two decades have reported a high prevalence of gastro-esophageal reflux disease (GERD) and esophageal dysmotility in the ALD population and several investigations suggest the prevalence may increase following lung transplantation. More recent studies evaluating the direct effect of gastro-duodenal contents on airways have demonstrated a possible biologic link between GERD and BOS. Despite the recent advances in our understanding of BOS, further investigations are needed to establish GERD as a causative factor in its development. This review will discuss the existing literature that has identified an association of GERD with ALD and post-transplant populations, with a focus on recent advances in the field.

A pneumocyte-macrophage paracrine lipid axis drives the lung toward fibrosis

Lipid-laden macrophages, or "foam cells," are observed in the lungs of patients with fibrotic lung disease, but their contribution to disease pathogenesis remains unexplored. Here, we demonstrate that fibrosis induced by bleomycin, silica dust, or thoracic radiation promotes early and sustained accumulation of foam cells in the lung. In the bleomycin model, we show that foam cells arise from neighboring alveolar epithelial type II cells, which respond to injury by dumping lipids into the distal airspaces of the lungs. We demonstrate that oxidized phospholipids accumulate within alveolar macrophages (AMs) after bleomycin injury and that murine and human AMs treated with oxidized phosphatidylcholine (oxPc) become polarized along an M2 phenotype and display enhanced production of transforming growth factor-β1. The direct instillation of oxPc into the mouse lung induces foam cell formation and triggers a severe fibrotic reaction. Further, we show that reducing pulmonary lipid clearance by targeted deletion of the lipid efflux transporter ATP-binding cassette subfamily G member 1 increases foam cell formation and worsens lung fibrosis after bleomycin. Conversely, we found that treatment with granulocyte-macrophage colony-stimulating factor attenuates fibrotic responses, at least in part through its ability to decrease AM lipid accumulation. In summary, this work describes a novel mechanism leading to foam cell formation in the mouse lung and suggests that strategies aimed at blocking foam cell formation might be effective for treating fibrotic lung disorders.

Prevalence of gastroesophageal reflux in cystic fibrosis and implications for lung disease

Gastroesophageal reflux (GER) is common in patients with cystic fibrosis (CF) and is often regarded as playing a role in the pathogenesis of CF lung disease. Individuals with CF have many predisposing factors to the development of GER, with a reported prevalence ranging from 35 to 81%. Several studies have suggested that patients with CF who have coexisting GER have more severe lung disease with lower pulmonary function and increased numbers of respiratory exacerbations. Furthermore, GER may alter the respiratory microbiology in CF. Both the acid and nonacid components of GER may have an effect on lung disease. More than 50% of U.S. patients with CF were being treated with proton pump inhibitors in 2012; however, data regarding safety and efficacy of these agents in CF are lacking. Pharmacologic and surgical treatment of GER may improve respiratory morbidity, although prospective controlled studies have not been performed. Given the lack of evidence-based guidelines for evaluation, diagnosis, and treatment of GER in CF, initiation of treatment for symptomatic GER should be based on standard guidelines for the general population. Because there is no clear evidence that GER leads to worse respiratory outcomes in CF or that treatment of GER improves pulmonary outcomes, invasive testing for GER in patients without reflux symptoms is not warranted. Further studies to determine the role of GER in CF lung disease and the risks and benefits of surgical and pharmacologic therapy for GER are warranted.

Lung transplantation in patients with cystic fibrosis: special focus to infection and comorbidities

Despite advances in medical care, patients with cystic fibrosis still face limited life expectancy. The most common cause of death remains respiratory failure. End-stage cystic fibrosis can be treated with lung transplantation and is the third most common reason for which the procedure is performed. Outcomes for cystic fibrosis are better than most other lung diseases, but remain limited (5-year survival 60%). For patients with advanced disease lung transplantation appears to improve survival. Outcomes for patients with Burkholderia cepacia remain poor, although they are better for patients with certain genomovars. Controversy exists about Mycobacterium abscessus infection and appropriateness for transplant. More information is also becoming available for comorbidities, including diabetes and pulmonary hypertension among others. Extra-corporeal membrane oxygenation is used more frequently for end-stage disease as a bridge to lung transplantation and will likely be used more in the future.

Lipid-laden bronchoalveolar macrophages in asthma and chronic cough

BACKGROUND

The presence of lipids in alveolar macrophages (AMs) may impair their phagocytic response, and determine airway inflammation and obstruction.

OBJECTIVE

To determine the factors such as severity of asthma, chronic cough, airway inflammation and obesity that may influence the presence of lipids in lung macrophages.

METHODS

Bronchoalveolar lavage fluid (BALF) was obtained from 38 asthmatics (21 severe and 17 mild/moderate), 16 subjects with chronic cough and 11 healthy control subjects. The presence of lipids in macrophages was detected using an Oil-red-O stain and an index of lipid-laden macrophages (LLMI) was obtained.

RESULTS

LLMI scores were higher in healthy subjects (median 48 [IQR 10-61]) and the severe asthma group (37 [11.5-61]) compared to mild/moderate asthmatics (7 [0.5-37]; p < 0.05 each). Subjects reporting a history of gastro-oesophageal reflux disease (GORD) had higher LLMI values (41.5 [11.3-138] versus 13 [0-39.3], p = 0.02). There was no significant correlation between LLMI and chronic cough, BAL cell differential counts, FEV1, FEV1/FVC or body mass index (BMI).

CONCLUSIONS

The reduced LLMI in mild/moderate asthma may be related to lower incidence of GORD. However, this was not related to the degree of airflow obstruction, obesity or airway inflammation.