Alterations of pulmonary function in patients with inflammatory bowel diseases

Development of severe colitis is associated with lung inflammation and pathology

Inflammatory bowel diseases (IBD) such as Crohn’s disease and ulcerative colitis are chronic relapsing diseases that affect the gastrointestinal tract, most commonly the colon. A link between the gut and the lung is suggested since patients with IBD have an increased susceptibility for chronic inflammatory lung disease. Furthermore, in the absence of overt lung disease, IBD patients have worsened lung function and more leukocytes in sputum than healthy individuals, highlighting a conduit between the gut and lung in disease. To study the gut-lung axis in the context of IBD, we used TCRδ-/- mice, which are highly susceptible to dextran sulfate sodium (DSS) due to the importance of γδ T cells in maintenance of barrier integrity. After induction of experimental colitis using DSS, the lungs of TCRδ-/- mice exhibited signs of inflammation and mild emphysema, which was not observed in DSS-treated C57BL/6 mice. Damage to the lung tissue was accompanied by a large expansion of neutrophils in the lung parenchyma and an increase in alveolar macrophages in the lung wash. Gene expression analyses showed a significant increase in Csf3, Cxcl2, Tnfa, and Il17a in lung tissue in keeping with neutrophil infiltration. Expression of genes encoding reactive oxygen species enzymes and elastolytic enzymes were enhanced in the lungs of both C57BL/6 and TCRδ-/- mice with colitis. Similarly, surfactant gene expression was also enhanced, which may represent a protective mechanism. These data demonstrate that severe colitis in a susceptible genetic background is sufficient to induce lung inflammation and tissue damage, providing the research community with an important tool for the development of novel therapeutics aimed at reducing co-morbidities in IBD patients.

Pulmonary Function in Paediatric Patients with Inflammatory Bowel Disease

BACKGROUND

Among the extraintestinal manifestations of inflammatory bowel disease (IBD), those involving the lungs are relatively rare and often overlooked. There are only scarce data on the prevalence of IBD-associated lung involvement in children.

OBJECTIVES

The aim of our study was to assess pulmonary function in IBD children by different methods and to evaluate the influence of immunosuppressive therapy on disease severity.

METHODS

Seventy-two children with IBD (mean age of 14.45 ± 2.27 years) and 40 age-matched healthy controls (mean age of 14.17 ± 2.82) were included in the study. Pulmonary function tests (PFTs) were carried out by means of spirometry, oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) to assess the pulmonary involvement.

RESULTS

Certain differences were observed between the study group and the control group, regarding the spirometric and oscillometry parameters. The fractions of exhaled nitric oxide did not differ between the group with IBD patients and the control group with regards to disease activity, the duration of illness and the administered immunosuppressive treatment.

CONCLUSIONS

The mean spirometry results were significantly different in the study group compared to the controls, although they were still within the normal limits. The pulmonary function abnormalities did not depend on either the disease activity or the immunosuppressive therapy. Oscillometry could be a supplementary method to assess pulmonary resistance. In turn, FeNO does not appear to be useful either in screening IBD children for pulmonary involvement or for the evaluation of disease activity. It appears then that only general screening of asymptomatic patients is a suitable method and a necessary recommendation in this population, prompting a revision of the current diagnostic approach.

Respiratory Tract Manifestations of Inflammatory Bowel Disease

Inflammatory bowel disease can manifest in many extraintestinal organ systems. The most frequently involved extraintestinal locations include the mucocutaneous, hepatobiliary, and ocular organ systems. The respiratory tract is less commonly involved and is therefore frequently overlooked. Consequently, it is believed that involvement of the respiratory tract in patients with inflammatory bowel disease is underreported. The pathogenesis is thought to be multifactorial, involving the common embryologic origin shared by the respiratory and luminal digestive tract, molecular mimicry, and immunologic interactions leading to immune-complex deposition in affected tissue. The spectrum of manifestations of the respiratory tract related to inflammatory bowel disease is broad. It not only includes direct involvement of the respiratory tract (ie, airways, interstitium, and pleura) but also can result as a consequence of systemic involvement such as in thromboembolic events. In addition, it may also be related to other conditions that affect the respiratory tract such as sarcoidosis and alpha-1 antitrypsin deficiency. Though some conditions related to respiratory tract involvement might be subclinical, others may have life-threatening consequences. It is critical to approach patients with suspected inflammatory bowel disease-related respiratory tract involvement in concert with pulmonology, infectious diseases, and any other pertinent experts, as treatments may require a multidisciplinary overlap of measures. Therefore, it is of paramount importance for the clinician to be aware of the array of respiratory tract manifestations of patients with inflammatory bowel disease, in addition to the possible spectrum of therapeutic measures.

Genetic association and causal inference converge on hyperglycaemia as a modifiable factor to improve lung function

Measures of lung function are heritable, and thus, we sought to utilise genetics to propose drug-repurposing candidates that could improve respiratory outcomes. Lung function measures were found to be genetically correlated with seven druggable biochemical traits, with further evidence of a causal relationship between increased fasting glucose and diminished lung function. Moreover, we developed polygenic scores for lung function specifically within pathways with known drug targets and investigated their relationship with pulmonary phenotypes and gene expression in independent cohorts to prioritise individuals who may benefit from particular drug-repurposing opportunities. A transcriptome-wide association study (TWAS) of lung function was then performed which identified several drug–gene interactions with predicted lung function increasing modes of action. Drugs that regulate blood glucose were uncovered through both polygenic scoring and TWAS methodologies. In summary, we provided genetic justification for a number of novel drug-repurposing opportunities that could improve lung function.

Chronic respiratory disorders like asthma affect around 600 million people worldwide. Although these illnesses are widespread, they can have several different underlying causes, making them difficult to treat. Drugs that work well on one type of respiratory disorder may be completely ineffective on another. Understanding the biological and environmental factors that cause these illnesses will allow them to be treated more effectively by tailoring therapies to each patient.

Reduced lung function is a factor in respiratory disorders and it can have many genetic causes. Studying the genes of patients with reduced lung function can reveal the genes involved, some of which may already be targets of existing drugs for other illnesses. So, could a patient’s genetics be used to repurpose existing drugs to treat their respiratory disorders?

Reay et al. combined three methods to link genetics and biological processes to the causes of reduced lung function. The results reveal several factors that could lead to new treatments. In one example, reduced lung function showed a link to genes associated with high blood sugar. As such, treatments used in diabetes might help improve lung function in some patients. Reay et al. also developed a scoring system that could predict the efficacy of a treatment based on a patient’s genetics. The study suggests that COVID-19 infection could be affected by blood sugar levels too.

Chronic respiratory disorders are a critical issue worldwide and have proven difficult to treat, but these results suggest a way to identify new therapies and target them to the right patients. The findings also support a connection between lung function and blood sugar levels. This implies that perhaps existing diabetes treatments – including diet and lifestyle changes aimed at reducing or limiting blood sugar – could be repurposed to treat respiratory disorders in some patients. The next step will be to perform clinical trials to test whether these therapies are in fact effective.

Pulmonary Manifestations of Gastrointestinal, Pancreatic, and Liver Diseases in Children

Pulmonary manifestations of gastrointestinal (GI) diseases are often subtle, and underlying disease may precede overt symptoms. A high index of suspicion and a low threshold for consultation with a pediatric pulmonologist is warranted in common GI conditions. This article outlines the pulmonary manifestations of different GI, pancreatic, and liver diseases in children, including gastroesophageal reflux disease, inflammatory bowel disease, pancreatitis, alpha1-antitrypsin deficiency, nonalcoholic fatty liver disease, and complications of chronic liver disease (hepatopulmonary syndrome and portopulmonary hypertension).

Links Between Inflammatory Bowel Disease and Chronic Obstructive Pulmonary Disease

Inflammatory bowel disease (IBD) and chronic obstructive pulmonary disease (COPD) are chronic inflammatory diseases of the gastrointestinal and respiratory tracts, respectively. These mucosal tissues bear commonalities in embryology, structure and physiology. Inherent similarities in immune responses at the two sites, as well as overlapping environmental risk factors, help to explain the increase in prevalence of IBD amongst COPD patients. Over the past decade, a tremendous amount of research has been conducted to define the microbiological makeup of the intestine, known as the intestinal microbiota, and determine its contribution to health and disease. Intestinal microbial dysbiosis is now known to be associated with IBD where it impacts upon intestinal epithelial barrier integrity and leads to augmented immune responses and the perpetuation of chronic inflammation. While much less is known about the lung microbiota, like the intestine, it has its own distinct, diverse microflora, with dysbiosis being reported in respiratory disease settings such as COPD. Recent research has begun to delineate the interaction or crosstalk between the lung and the intestine and how this may influence, or be influenced by, the microbiota. It is now known that microbial products and metabolites can be transferred from the intestine to the lung via the bloodstream, providing a mechanism for communication. While recent studies indicate that intestinal microbiota can influence respiratory health, intestinal dysbiosis in COPD has not yet been described although it is anticipated since factors that lead to dysbiosis are similarly associated with COPD. This review will focus on the gut-lung axis in the context of IBD and COPD, highlighting the role of environmental and genetic factors and the impact of microbial dysbiosis on chronic inflammation in the intestinal tract and lung.

Pulmonary Manifestations of Inflammatory Bowel Disease

Pulmonary manifestations of inflammatory bowel disease are increasingly recognized in patients with ulcerative colitis and Crohn's disease. Most commonly, incidental abnormalities are noted on chest imaging or pulmonary function tests. Although clinically significant pulmonary disease is less common, it can carry significant morbidity for patients. We review the presenting symptoms, workup, and management for several of the more common forms of inflammatory bowel disease-related pulmonary disease. Increased awareness of the spectrum of extraintestinal inflammatory bowel disease will help providers more readily recognize this phenomenon in their own patients and more comprehensively address the protean sequelae of inflammatory bowel disease.

A comprehensive review and update on ulcerative colitis. Dis Mon 2019;65:100851. [PMID: 30837080 DOI: 10.1016/j.disamonth.2019.02.004]

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disorder of the colon that causes continuous mucosal inflammation extending from the rectum to the more proximal colon, with variable extents. UC is characterized by a relapsing and remitting course. UC was first described by Samuel Wilks in 1859 and it is more common than Crohn's disease worldwide. The overall incidence and prevalence of UC is reported to be 1.2-20.3 and 7.6-245 cases per 100,000 persons/year respectively. UC has a bimodal age distribution with an incidence peak in the 2nd or 3rd decades and followed by second peak between 50 and 80 years of age. The key risk factors for UC include genetics, environmental factors, autoimmunity and gut microbiota. The classic presentation of UC include bloody diarrhea with or without mucus, rectal urgency, tenesmus, and variable degrees of abdominal pain that is often relieved by defecation. UC is diagnosed based on the combination of clinical presentation, endoscopic findings, histology, and the absence of alternative diagnoses. In addition to confirming the diagnosis of UC, it is also important to define the extent and severity of inflammation, which aids in the selection of appropriate treatment and for predicting the patient's prognosis. Ileocolonoscopy with biopsy is the only way to make a definitive diagnosis of UC. A pathognomonic finding of UC is the presence of continuous colonic inflammation characterized by erythema, loss of normal vascular pattern, granularity, erosions, friability, bleeding, and ulcerations, with distinct demarcation between inflamed and non-inflamed bowel. Histopathology is the definitive tool in diagnosing UC, assessing the disease severity and identifying intraepithelial neoplasia (dysplasia) or cancer. The classical histological changes in UC include decreased crypt density, crypt architectural distortion, irregular mucosal surface and heavy diffuse transmucosal inflammation, in the absence of genuine granulomas. Abdominal computed tomographic (CT) scanning is the preferred initial radiographic imaging study in UC patients with acute abdominal symptoms. The hallmark CT finding of UC is mural thickening with a mean wall thickness of 8 mm, as opposed to a 2-3 mm mean wall thickness of the normal colon. The Mayo scoring system is a commonly used index to assess disease severity and monitor patients during therapy. The goals of treatment in UC are three fold-improve quality of life, achieve steroid free remission and minimize the risk of cancer. The choice of treatment depends on disease extent, severity and the course of the disease. For proctitis, topical 5-aminosalicylic acid (5-ASA) drugs are used as the first line agents. UC patients with more extensive or severe disease should be treated with a combination of oral and topical 5-ASA drugs +/- corticosteroids to induce remission. Patients with severe UC need to be hospitalized for treatment. The options in these patients include intravenous steroids and if refractory, calcineurin inhibitors (cyclosporine, tacrolimus) or tumor necrosis factor-α antibodies (infliximab) are utilized. Once remission is induced, patients are then continued on appropriate medications to maintain remission. Indications for emergency surgery include refractory toxic megacolon, colonic perforation, or severe colorectal bleeding.

Pulmonary dysfunction in 114 patients with inflammatory bowel disease

This study aimed to investigate the pulmonary function in patients with inflammatory bowel disease (IBD) and its clinical feature and risk factors.One hundred fourteen patients with IBD and 120 healthy subjects were recruited. The medical information including general situation, biochemical examinations, lung function, and the treatment was recorded and analyzed.In 107 patients (107/114, 93.86%), lung function testing showed the pulmonary ventilation, residual volume, and pulmonary diffusion in IBD patients significantly increased as compared to controls (P < .05). No significant differences were observed between ulcerative colitis (UC) patients and Crohn disease (CD) patients (P > .05). However, the vital capacity, forced vital capacity, MVV, forced expiratory volume in first second, peak expiratory flow rate, and maximum mid-expiratory flow in IBD patients significantly decreased when compared with controls (P < .01). There was no significant correlation between pulmonary function and severity and extent of IBD. The chronicity of inflammation might probably reduce the possibility of developing pulmonary dysfunction, while the erythrocyte sedimentation rate (ESR) was found as a harmful factor for developing pulmonary dysfunction.The pulmonary function significantly decreases in IBD patients and is characterized by either simple restrictive/obstructive dysfunction or mixed. The pulmonary function of IBD patients has no relationship with the severity and extent of IBD. IBD combined with pulmonary dysfunction was imperceptible, and clinicians could consider performing pulmonary function testing for IBD patient as many as possible, especially for those who have high level of ESR or any respiratory symptoms like cough, in order to avoid severe pulmonary damage.