Translational research in pediatrics III: bronchoalveolar lavage

Pulmonary and Clinical Outcomes After Bilateral Submandibular Gland Excision and Parotid Duct Ligation for Refractory Sialorrhea

Importance

Refractory sialorrhea in children can result in pulmonary aspiration and irreversible lung damage. Despite many studies devoted to the surgical treatment of sialorrhea, there is a paucity of objective outcome measures after surgery, especially with regard to pulmonary health.

Objectives

To assess whether bilateral submandibular gland excision and bilateral parotid duct ligation ("DROOL" procedure) is associated with reduced pulmonary inflammation in bronchoalveolar lavage (BAL) samples after surgery and to assess patient factors associated with improvement after surgery.

Design, Setting, and Participants

This retrospective case series included all 112 patients undergoing the DROOL procedure at a single tertiary care pediatric children's hospital from January 1, 2012, to December 31, 2021. Statistical analysis was performed from March 30 to June 10, 2023, and August 20 to September 23, 2023.

Exposure

DROOL procedure for refractory sialorrhea.

Main Outcomes and Measures

Degree of pulmonary inflammation (neutrophil percentage) according to BAL cytologic findings and overall bronchoscopy findings up to 12 months before and after the DROOL procedure. Secondary outcomes included number of annual hospitalizations, caregiver report of function before and after the procedure, and need for revision procedures and/or additional operations for secretion management.

Results

A total of 112 patients (median age, 3.4 years [IQR, 2.0-7.1 years]; 65 boys [58.0%]) underwent DROOL procedures and had both preoperative and postoperative BAL samples during the study period. Patients demonstrated objective improvement in pulmonary inflammation after surgery, with the median polymorphonuclear neutrophil percentage decreasing from 65.0% (IQR, 14.0%-86.0%) before the surgery to 32.5% (IQR, 3.0%-76.5%) after the surgery (median difference in percentage points, -9.0 [95% CI, -20.0 to 0.0]). Prior to the DROOL procedure, 34 patients (30.4%; 95% CI, 21.8%-38.9%) were hospitalized 2 or more times annually for respiratory illness, which decreased to 10.1% (11 of 109; 95% CI, 4.4%-15.7%) after surgery (3 patients did not have hospitalization data available following surgery). Most caretakers (73 [65.2%]) reported improved secretion management after the procedure.

Conclusions and Relevance

This study suggests that patients with impaired secretion management who underwent a DROOL procedure demonstrated improvement in pulmonary inflammation and a reduction in hospitalizations after surgery. Caretakers were also likely to report subjective improvement in secretion management and quality of life. Additional research is necessary to guide optimal timing and patient selection for this procedure.

Pulmonary microbiome and transcriptome signatures reveal distinct pathobiologic states associated with mortality in two cohorts of pediatric stem cell transplant patients

Lung injury is a major determinant of survival after pediatric hematopoietic cell transplantation (HCT). A deeper understanding of the relationship between pulmonary microbes, immunity, and the lung epithelium is needed to improve outcomes. In this multicenter study, we collected 278 bronchoalveolar lavage (BAL) samples from 229 patients treated at 32 children's hospitals between 2014-2022. Using paired metatranscriptomes and human gene expression data, we identified 4 patient clusters with varying BAL composition. Among those requiring respiratory support prior to sampling, in-hospital mortality varied from 22-60% depending on the cluster (p=0.007). The most common patient subtype, Cluster 1, showed a moderate quantity and high diversity of commensal microbes with robust metabolic activity, low rates of infection, gene expression indicating alveolar macrophage predominance, and low mortality. The second most common cluster showed a very high burden of airway microbes, gene expression enriched for neutrophil signaling, frequent bacterial infections, and moderate mortality. Cluster 3 showed significant depletion of commensal microbes, a loss of biodiversity, gene expression indicative of fibroproliferative pathways, increased viral and fungal pathogens, and high mortality. Finally, Cluster 4 showed profound microbiome depletion with enrichment of Staphylococci and viruses, gene expression driven by lymphocyte activation and cellular injury, and the highest mortality. BAL clusters were modeled with a random forest classifier and reproduced in a geographically distinct validation cohort of 57 patients from The Netherlands, recapitulating similar cluster-based mortality differences (p=0.022). Degree of antibiotic exposure was strongly associated with depletion of BAL microbes and enrichment of fungi. Potential pathogens were parsed from all detected microbes by analyzing each BAL microbe relative to the overall microbiome composition, which yielded increased sensitivity for numerous previously occult pathogens. These findings support personalized interpretation of the pulmonary microenvironment in pediatric HCT, which may facilitate biology-targeted interventions to improve outcomes.

Pediatric bronchoscopy: recent advances and clinical challenges

Introduction: During the last 40 years equipment has been improved with smaller instruments and sufficient size working channels. This has ensured that bronchoscopy offers therapeutic and interventional options.Areas covered: We provide a review of recent advances and clinical challenges in pediatric bronchoscopy. This includes single-use bronchoscopes, endobronchial ultrasound, and cryoprobe. Bronchoscopy in persistent preschool wheezing and asthma is included. The indications for interventional bronchoscopy have amplified and included balloon dilatation, endoscopic intubation, the use of airway stents, whole lung lavage, closing of fistulas and air leak, as well as an update on removal of foreign bodies. Others include the use of laser and microdebrider in airway surgery. Experience with bronchoscope during the COVID-19 pandemic has been included in this review. PubMed was searched for articles on pediatric bronchoscopy, including rigid bronchoscopy as well as interventional bronchoscopy with a focus on reviewing literature in the past 5 years.Expert opinion: As the proficiency of pediatric interventional pulmonologists continues to grow more interventions are being performed. There is a scarcity of published evidence in this field. Courses for pediatric interventional bronchoscopy need to be developed. The COVID-19 experience resulted in safer bronchoscopy practice for all involved.

Pre-analytical Practices in the Molecular Diagnostic Tests, A Concise Review

Molecular assays for detection of nucleic acids in biologic specimens are valuable diagnostic tools supporting clinical diagnoses and therapeutic decisions. Pre-analytical errors, which occur before or during processing of nucleic acid extraction, contribute a significant role in common errors that take place in molecular laboratories. Certain practices in specimen collection, transportation, and storage can affect the integrity of nucleic acids before analysis. Applying best practices in these steps, helps to minimize those errors and leads to better decisions in patient diagnosis and treatment. Widely acceptable recommendations, which are for optimal molecular assays associated with pre-analytic variables, are limited. In this article, we have reviewed most of the important issues in sample handling from bed to bench before starting molecular tests, which can be used in diagnostic as well as research laboratories. We have addressed the most important pre-analytical points in performing molecular analysis in fixed and unfixed solid tissues, whole blood, serum, plasma, as well as most of the body fluids including urine, fecal and bronchial samples, as well as prenatal diagnosis samples.

Tannic acid alleviates experimental pulmonary fibrosis in mice by inhibiting inflammatory response and fibrotic process

Pulmonary fibrosis (PF) is a chronic and irreversible scarring disease in the lung with limited treatment options. Therefore, it is critical to identify new therapeutic options. This study was undertaken to identify the effects of tannic acid (TA), a naturally occurring dietary polyphenol, in a mouse model of PF. Bleomycin (BLM) was intratracheally administered to induce PF. Administration of TA significantly reduced BLM-induced histological alterations, inflammatory cell infiltration and the levels of various inflammatory mediators (nitric oxide, leukotriene B₄ and cytokines). Additionally, treatment with TA also impaired BLM-mediated increases in pro-fibrotic (transforming growth factor-β1) and fibrotic markers (alpha-smooth muscle actin, vimentin, collagen 1 alpha and fibronectin) expression. Further investigation indicated that BLM-induced phosphorylation of Erk1/2 (extracellular signal-regulated kinases 1 and 2) in lungs was suppressed by TA treatment. Findings of this study suggest that TA has the potential to mitigate PF through inhibiting the inflammatory response and fibrotic process in lungs and that TA might be useful for the treatment of PF in clinical practice.

Emergent high fatality lung disease in systemic juvenile arthritis

OBJECTIVE

To investigate the characteristics and risk factors of a novel parenchymal lung disease (LD), increasingly detected in systemic juvenile idiopathic arthritis (sJIA).

METHODS

In a multicentre retrospective study, 61 cases were investigated using physician-reported clinical information and centralised analyses of radiological, pathological and genetic data.

RESULTS

LD was associated with distinctive features, including acute erythematous clubbing and a high frequency of anaphylactic reactions to the interleukin (IL)-6 inhibitor, tocilizumab. Serum ferritin elevation and/or significant lymphopaenia preceded LD detection. The most prevalent chest CT pattern was septal thickening, involving the periphery of multiple lobes ± ground-glass opacities. The predominant pathology (23 of 36) was pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia (PAP/ELP), with atypical features including regional involvement and concomitant vascular changes. Apparent severe delayed drug hypersensitivity occurred in some cases. The 5-year survival was 42%. Whole exome sequencing (20 of 61) did not identify a novel monogenic defect or likely causal PAP-related or macrophage activation syndrome (MAS)-related mutations. Trisomy 21 and young sJIA onset increased LD risk. Exposure to IL-1 and IL-6 inhibitors (46 of 61) was associated with multiple LD features. By several indicators, severity of sJIA was comparable in drug-exposed subjects and published sJIA cohorts. MAS at sJIA onset was increased in the drug-exposed, but was not associated with LD features.

CONCLUSIONS

A rare, life-threatening lung disease in sJIA is defined by a constellation of unusual clinical characteristics. The pathology, a PAP/ELP variant, suggests macrophage dysfunction. Inhibitor exposure may promote LD, independent of sJIA severity, in a small subset of treated patients. Treatment/prevention strategies are needed.

Collection and Analyses of Cerebrospinal Fluid for Pediatric Translational Research

Cerebrospinal fluid sample collection and analysis is imperative to better elucidate central nervous system injury and disease in children. Sample collection methods are varied and carry with them certain ethical and biologic considerations, complications, and contraindications. Establishing best practices for sample collection, processing, storage, and transport will ensure optimal sample quality. Cerebrospinal fluid samples can be affected by a number of factors including subject age, sampling method, sampling location, volume extracted, fraction, blood contamination, storage methods, and freeze-thaw cycles. Indicators of sample quality can be assessed by matrix-associated laser desorption/ionization time-of-flight mass spectrometry and include cystatin C fragments, oxidized proteins, prostaglandin D synthase, and evidence of blood contamination. Precise documentation of sample collection processes and the establishment of meticulous handling procedures are essential for the creation of clinically relevant biospecimen repositories. In this review we discuss the ethical considerations and best practices for cerebrospinal fluid collection, as well as the influence of preanalytical factors on cerebrospinal fluid analyses. Cerebrospinal fluid biomarkers in highly researched pediatric diseases or disorders are discussed.

Multiplex PCR of bronchoalveolar lavage fluid in children enhances the rate of pathogen detection

Background

Culturing of bronchoalveolar lavage (BAL) fluid is a commonly used method for pathogen detection in pneumonia. However, the sensitivity is low, especially in patients pre-treated with anti-infective agents. The early detection of a pathogen is crucial for the outcome of respiratory tract infections. For bloodstream infections, a multiplex polymerase chain reaction (PCR) assay (SeptiFast®, SF) is available for improved pathogen detection from blood.

Objective

The aim of the present study was to determine whether the SF assay is applicable to the BAL of children with pulmonary infections and whether the frequency of pathogen detection is enhanced by the use of this multiplex PCR method.

Methods

We investigated 70 BAL samples of 70 children simultaneously by culture and multiplex PCR. The frequency of pathogen detection was compared.

Results

Pathogens were detected more frequently by SF than by culture (83% vs. 31%; p < 0.001). This advantage was shown for immunocompetent patients (p = 0.001) as well as for immunocompromised patients (p = 0.003). The majority (38/44; 86%) of the Gram positive cocci were only detected by SF. Fungal organisms were detected in 7/70 patients (10%) by SF and in 2/70 (3%) by culture (p = 0.125).

Conclusion

Compared to conventional culture, the use of the SF assay on the BAL of children with pneumonia increases pathogen detection rates and therefore adds important information to guide anti-infective therapy.

Quadruplex real-time PCR for rapid detection of human alphaherpesviruses

Infections with the herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) as well as with the varicella-zoster virus (VZV) may take a serious course. Thus, rapid and reliable detection of these alphaherpesviruses is urgently needed. For this, we established a qualitative quadruplex real-time polymerase chain reaction (PCR) covering HSV-1, HSV-2, VZV and endogenous human glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The PCR was validated with quality assessment samples and pre-characterized clinical samples including swabs, blood and cerebrospinal as well as respiratory fluids. For comparison, nucleic acids (NA) of selected samples were extracted manually and automatically. The protocol takes approx. 90 min, starting with the preparation of NA until the report of results. The oligonucleotide and hydrolysis probe sequences specifically detect and distinguish HSV-1 (530 nm), HSV-2 (705 nm) and VZV (560 nm) DNA. The detection limit was estimated with 100-500 copies/ml HSV-1 and HSV-2/VZV, respectively. All quality assessment samples as well as all the patient samples were classified correctly. Parallel detection of GAPDH (670 nm) DNA was implemented to demonstrate correct sampling, but was uncertain in case of swabs. To this end, alphaherpesvirus-free human DNA was also added directly into the mastermix to exclude PCR inhibition. The established protocol for parallel detection and differentiation of alphaherpesviruses is fast, highly specific as well as rather sensitive. It will facilitate HSV-1/2 and VZV diagnostics and may be further improved by opening the 670 nm channel for a combined extraction and PCR inhibition control.

Towards developing a valid scoring tool for bronchitis during flexible bronchoscopy

BACKGROUND

A valid bronchoscopic scoring tool for bronchitis would be useful for clinical and research purposes as currently there are none in children. From 100 digitally recorded flexible bronchoscopies (FB), we related the various macroscopic features to airway neutrophil % to develop a FB-derived bronchitis score (BScore_exp ). We aimed to develop a FB-derived bronchitis tool.

METHODS

FB recordings for six visualised features: secretions (amount and color) and mucosal appearance (erythema, pallor, ridging, oedema) based on pre-determined criteria on a pictorial chart were assessed by two physicians independently, blinded to the clinical history. These features were used to obtain various models of BScore_exp that were plotted against bronchoalveolar lavage (BAL) neutrophil % using a receiver operating characteristic (ROC) curve. Inter- and intra-rater agreement (weighted-kappa, K) were assessed from 30 FBs.

RESULTS

Using BAL neutrophilia of 20% to define inflammation, the highest area under ROC (aROC) of 0.71, 95%CI 0.61-0.82 was obtained by the giving three times weightage to secretion amount and color and adding it to erythema and oedema. Inter-rater K values for secretion amount (K = 0.87, 95%CI 0.73-1.0) and color (K = 0.86, 95%CI 0.69-1.0) were excellent. Respective intra-rater K were 0.95 (0.87-1.0) and 0.68 (0.47-0.89). Other inter-rater K ranged from 0.4 (erythema) to 0.64 (pallor).

CONCLUSION

A repeatable FB-defined bronchitis scoring tool can be derived. However, a prospective study needs to be performed with larger numbers to further evaluate and validate these results.

The early examination of combined serum and imaging data under flexible fiberoptic bronchoscopy as a novel predictor for refractory Mycoplasma pneumoniae pneumonia diagnosis

The treatment role of flexible bronchoscopy (FOB) for pediatric refractory Mycoplasma pneumoniae pneumonia (RMPP) has been well documented. Besides, the application indication of FOB is also studied in patients with general MPP (GMPP), especially in those with large pulmonary lesions. This study was designed to examine the diagnostic value of bronchoscopic features for RMPP.The FOB and bronchoalveolar lavage (BAL) were adopted for pediatric patients who showed clinical and radiograph indications. On the basis of the final diagnosis on discharge, patients were divided into general and refractory MPP groups. The clinical, laboratory, and bronchoscopic imaging features were retrospectively investigated between these 2 groups.From June 2012 to May 2014, a total of 62 RMPP and 101 GMPP patients were treated with therapeutic bronchoscopy. The comparison analysis showed that the CRP, HBDH, LDH were significantly different between RMPP and GMPP groups (all P < .001). In the bronchoscopic imaging, the mucus plug was significantly more commonly seen in the RMPP group (P < .001). Receiver operating characteristic (ROC) analysis revealed that the combined serum, clinical, and FOB imaging data possessed greater specificity and sensitivity than serum and clinical data alone.Our data suggest that the combined serum, clinical, and bronchoscopic imaging data might serve as a promising predictor for early RMPP diagnosis for pediatric patients with large pulmonary lesions.

Approaches to Evaluate Lung Inflammation in Translational Research

Inflammation is a common feature in several types of lung disease and is a frequent end point to validate lung disease models, evaluate genetic or environmental impact on disease severity, or test the efficacy of new therapies. Questions relevant to a study should be defined during experimental design and techniques selected to specifically address these scientific queries. In this review, the authors focus primarily on the breadth of techniques to evaluate lung inflammation that have both clinical and preclinical applications. Stratification of approaches to assess lung inflammation can diminish weaknesses inherent to each technique, provide data validation, and increase the reproducibility of a study. Specialized techniques (eg, imaging, pathology) often require experienced personnel to collect, evaluate, and interpret the data; these experts should be active contributors to the research team through reporting of the data. Scoring of tissue lesions is a useful method to transform observational pathologic data into semiquantitative or quantitative data for statistical analysis and enhanced rigor. Each technique to evaluate lung inflammation has advantages and limitations; understanding these parameters can help identify approaches that best complement one another to increase the rigor and translational significance of data.

Aspiration techniques for bronchoalveolar lavage in translational respiratory research: Paving the way to develop novel therapeutic moieties

Bronchoalveolar lavage (BAL) is a simple, yet informative tool in understanding the immunopathology of various lung diseases via quantifying various inflammatory cells, cytokines and growth factors. At present, this traditional method is often blended with several robust and sophisticated molecular and biological techniques sustaining the significance and longevity of this technique. Crucially, the existence of slightly distinct approaches and variables employed at different laboratories around the globe in performing BAL aspiration indeed demands an utmost need to optimize and develop an effective, cost-effective and a reproducible technique. This mini review will be of importance to the biological translational scientist, particularly respiratory researchers in understanding the fundamentals and approaches to apply and consider with BAL aspiration techniques. This will ensure generating a meaningful and clinically relevant data which in turn accelerate the development of new and effective therapeutic moieties for major respiratory conditions.

Clinical utility of bronchoalveolar lavage cytomegalovirus viral loads in the diagnosis of cytomegalovirus pneumonitis in infants

Cytomegalovirus (CMV) pneumonitis is a significant cause of morbidity and mortality of children in Africa. The current practice for diagnosing CMV pneumonitis in this setting is based on interpretation of clinical, laboratory, and radiological findings. There is a need for a sensitive and specific laboratory test to objectively distinguish between patients with CMV pneumonitis and those with CMV infection, and non‐CMV pneumonia. In this study, we compared plasma and non‐bronchoscopic bronchoalveolar lavage (NBBAL) CMV viral loads in patients with CMV pneumonitis and those with CMV infection and non‐CMV pneumonia. Receiver operator characteristic curve analysis was used to establish a threshold and assess utility of viral loads in the diagnosis of CMV pneumonitis. We assessed the urea dilution method, and expression of viral loads relative to the total amount of extracted nucleic acids in correcting for NBBAL dilution. CMV quantification in NBBAL specimens was more predictive of CMV pneumonitis than blood CMV quantification. The threshold of 4.03 log IU/ml in NBBAL specimens has good predictive value and can be used to guide management of infants with suspected CMV pneumonitis. Adjusting for dilution of NBBAL specimens by using the urea dilution method or by expressing the viral load relative to the total nucleic acids extracted did not provide additional analytical benefits. J. Med. Virol. 89:1080–1087, 2017. © 2016 Wiley Periodicals, Inc.

Flexible bronchoscopy contribution in the approach of diagnosis and treatment of children's respiratory diseases: the experience of a unique pediatric unit in Tunisia

OBJECTIVE

Our study aimed at assessing the role of flexible bronchoscopy (FB) in improving diagnosis and management of children's respiratory conditions in the pediatric unit of FB, newly created and unique in Tunisia.

METHODS

Retrospective study including all the FB achieved in our pediatric unit from 2009 to 2014.

RESULTS

We performed 365 FB in 333 patients aged 46 months on average (1 month - 15 years), often under conscious anesthesia (81.6%). FB was performed for diagnostic purposes in 341 cases and for therapeutic purposes in 24 cases. Eight anatomical abnormalities were revealed in 22 patients. An intraluminal bronchial obstruction was found in 71 FB, mainly due to a foreign body (n=36). A vascular anomaly was responsible for nine cases out of 17 extraluminal obstructions. Airways malacia was observed in 60 FB. Bronchoalveolar lavage was performed in 196 cases. It was determinant in 43.9% of the cases. FB was of great diagnostic value in 74.8% of the cases. It influenced the management of the patients in 58% of the cases. The FB for therapeutic purposes was beneficial in all cases. Few complications occurred (5.5%).

CONCLUSION

FB is a safe tool providing precious diagnostic and/or therapeutic help for the clinician.

The proteomics of lung injury in childhood: challenges and opportunities

Proteomics, the large-scale study of the structure and function of proteins of a cell or organism, is a rapidly developing area of biomedical research which is perfectly suited to the study of pediatric lung injury, where a variety of samples are easily, and repeatedly, accessible including plasma (reflecting a whole body response) and broncheoalveolar lung fluid (reflecting the lungs response). When applied to pediatric lung injury, proteomics could be used to develop much needed early biomarkers of lung injury, elucidate pathological pathways and determine protein alterations associated with specific disease processes. However despite the obvious benefits and need, proteomics is rarely utilized in studies of pediatric injury. This review primarily reports on the last decade of pediatric research into proteomes associated with specific respiratory diseases including bronchopulmonary dysplasia, respiratory infection, cystic fibrosis and asthma whilst also reflecting on the challenges unique to proteomic studies of the pediatric respiratory disease population. We conclude that the number of key pathological differences between the pediatric and adult study populations inhibit inference of results from adult studies onto a pediatric population and necessitate studies of the pediatric proteome. Furthermore the disparity amongst pediatric lung disease in terms of age at onset and underlying pathological mechanism (genetic, immunological, intervention-based, developmental arrest, inhaled toxin) will require proteomic studies which are well designed, with large disease specific patient sets to ensure adequate power as well as matched controls. Regardless of causative agent, pulmonary biomarkers are needed to predict the clinical course of pediatric lung disease, status, progression and response to treatment. Identification of early biomarkers is particularly pertinent in order to understand the natural history of disease and monitor progression so prevention of ongoing lung injury and impact on childhood can targeted.

Translational Research in Pediatrics IV: Solid Tissue Collection and Processing

Solid tissues are critical for child-health research. Specimens are commonly obtained at the time of biopsy/surgery or postmortem. Research tissues can also be obtained at the time of organ retrieval for donation or from tissue that would otherwise have been discarded. Navigating the ethics of solid tissue collection from children is challenging, and optimal handling practices are imperative to maximize tissue quality. Fresh biopsy/surgical specimens can be affected by a variety of factors, including age, gender, BMI, relative humidity, freeze/thaw steps, and tissue fixation solutions. Postmortem tissues are also vulnerable to agonal factors, body storage temperature, and postmortem intervals. Nonoptimal tissue handling practices result in nucleotide degradation, decreased protein stability, artificial posttranslational protein modifications, and altered lipid concentrations. Tissue pH and tryptophan levels are 2 methods to judge the quality of solid tissue collected for research purposes; however, the RNA integrity number, together with analyses of housekeeping genes, is the new standard. A comprehensive clinical data set accompanying all tissue samples is imperative. In this review, we examined: the ethical standards relating to solid tissue procurement from children; potential sources of solid tissues; optimal practices for solid tissue processing, handling, and storage; and reliable markers of solid tissue quality.

Pediatric Pulmonology year in review 2014: Part 1

Our discipline and our journal cover an extremely broad range of research and scholarly topics related to children's respiratory disorders. To better meet the needs of our readership for updated perspectives on the rapidly expanding knowledge in our field, we here summarize the past year's publications in our major topic areas, as well as selected publications in these areas from the core clinical journal literature outside our own pages.