Cystic Fibrosis

The natural history and genetic diversity of Haemophilus influenzae infecting the airways of adults with cystic fibrosis

Wed, 2022-09-21 06:00

Sci Rep. 2022 Sep 21;12(1):15765. doi: 10.1038/s41598-022-19240-2.

ABSTRACT

Haemophilus influenzae is a Gram-negative pathobiont, frequently recovered from the airways of persons with cystic fibrosis (pwCF). Previous studies of H. influenzae infection dynamics and transmission in CF predominantly used molecular methods, lacking resolution. In this retrospective cohort study, representative yearly H. influenzae isolates from all pwCF attending the Calgary Adult CF Clinic with H. influenzae positive sputum cultures between 2002 and 2016 were typed by pulsed-field gel electrophoresis. Isolates with shared pulsotypes common to ≥ 2 pwCF were sequenced by Illumina MiSeq. Phylogenetic and pangenomic analyses were used to assess genetic relatedness within shared pulsotypes, and epidemiological investigations were performed to assess potential for healthcare associated transmission. H. influenzae infection was observed to be common (33% of patients followed) and dynamic in pwCF. Most infected pwCF exhibited serial infections with new pulsotypes (75% of pwCF with ≥ 2 positive cultures), with up to four distinct pulsotypes identified from individual patients. Prolonged infection by a single pulsotype was only rarely observed. Intra-patient genetic diversity was observed at the single-nucleotide polymorphism and gene content levels. Seven shared pulsotypes encompassing 39% of pwCF with H. influenzae infection were identified, but there was no evidence, within our sampling scheme, of direct patient-to-patient infection transmission.

PMID:36131075 | DOI:10.1038/s41598-022-19240-2

Categories: Literature Watch

Inverted direct allorecognition triggers early donor-specific antibody responses after transplantation

Wed, 2022-09-21 06:00

Sci Transl Med. 2022 Sep 21;14(663):eabg1046. doi: 10.1126/scitranslmed.abg1046. Epub 2022 Sep 21.

ABSTRACT

The generation of antibodies against donor-specific major histocompatibility complex (MHC) antigens, a type of donor-specific antibodies (DSAs), after transplantation requires that recipient's allospecific B cells receive help from T cells. The current dogma holds that this help is exclusively provided by the recipient's CD4+ T cells that recognize complexes of recipient's MHC II molecules and peptides derived from donor-specific MHC alloantigens, a process called indirect allorecognition. Here, we demonstrated that, after allogeneic heart transplantation, CD3ε knockout recipient mice lacking T cells generate a rapid, transient wave of switched alloantibodies, predominantly directed against MHC I molecules. This is due to the presence of donor CD4+ T cells within the graft that recognize intact recipient's MHC II molecules expressed by B cell receptor-activated allospecific B cells. Indirect evidence suggests that this inverted direct pathway is also operant in patients after transplantation. Resident memory donor CD4+ T cells were observed in perfusion liquids of human renal and lung grafts and acquired B cell helper functions upon in vitro stimulation. Furthermore, T follicular helper cells, specialized in helping B cells, were abundant in mucosa-associated lymphoid tissue of lung and intestinal grafts. In the latter, more graft-derived passenger T cells correlated with the detection of donor T cells in recipient's circulation; this, in turn, was associated with an early transient anti-MHC I DSA response and worse transplantation outcomes. We conclude that this inverted direct allorecognition is a possible explanation for the early transient anti-MHC DSA responses frequently observed after lung or intestinal transplantations.

PMID:36130013 | DOI:10.1126/scitranslmed.abg1046

Categories: Literature Watch

Pseudomonas aeruginosa Production of Hydrogen Cyanide Leads to Airborne Control of Staphylococcus aureus Growth in Biofilm and <em>In Vivo</em> Lung Environments

Wed, 2022-09-21 06:00

mBio. 2022 Sep 21:e0215422. doi: 10.1128/mbio.02154-22. Online ahead of print.

ABSTRACT

Diverse bacterial volatile compounds alter bacterial stress responses and physiology, but their contribution to population dynamics in polymicrobial communities is not well known. In this study, we showed that airborne volatile hydrogen cyanide (HCN) produced by a wide range of Pseudomonas aeruginosa clinical strains leads to at-a-distance in vitro inhibition of the growth of a wide array of Staphylococcus aureus strains. We determined that low-oxygen environments not only enhance P. aeruginosa HCN production but also increase S. aureus sensitivity to HCN, which impacts P. aeruginosa-S. aureus competition in microaerobic in vitro mixed biofilms as well as in an in vitro cystic fibrosis lung sputum medium. Consistently, we demonstrated that production of HCN by P. aeruginosa controls S. aureus growth in a mouse model of airways coinfected by P. aeruginosa and S. aureus. Our study therefore demonstrates that P. aeruginosa HCN contributes to local and distant airborne competition against S. aureus and potentially other HCN-sensitive bacteria in contexts relevant to cystic fibrosis and other polymicrobial infectious diseases. IMPORTANCE Airborne volatile compounds produced by bacteria are often only considered attractive or repulsive scents, but they also directly contribute to bacterial physiology. Here, we showed that volatile hydrogen cyanide (HCN) released by a wide range of Pseudomonas aeruginosa strains controls Staphylococcus aureus growth in low-oxygen in vitro biofilms or aggregates and in vivo lung environments. These results are of pathophysiological relevance, since lungs of cystic fibrosis patients are known to present microaerobic areas and to be commonly associated with the presence of S. aureus and P. aeruginosa in polymicrobial communities. Our study therefore provides insights into how a bacterial volatile compound can contribute to the exclusion of S. aureus and other HCN-sensitive competitors from P. aeruginosa ecological niches. It opens new perspectives for the management or monitoring of P. aeruginosa infections in lower-lung airway infections and other polymicrobial disease contexts.

PMID:36129311 | DOI:10.1128/mbio.02154-22

Categories: Literature Watch

Contribution of <em>Trp63<sup>CreERT2</sup></em> labeled cells to alveolar regeneration is independent of tuft cells

Wed, 2022-09-21 06:00

Elife. 2022 Sep 21;11:e78217. doi: 10.7554/eLife.78217. Online ahead of print.

ABSTRACT

Viral infection often causes severe damage to the lungs, leading to the appearance of ectopic basal cells (EBCs) and tuft cells in the lung parenchyma. Thus far the roles of these ectopic epithelial cells in alveolar regeneration remain controversial. Here, we confirm that the ectopic tuft cells are originated from EBCs in mouse models and COVID-19 lungs. The differentiation of tuft cells from EBCs is promoted by Wnt inhibition while suppressed by Notch inhibition. Although progenitor functions have been suggested in other organs, pulmonary tuft cells don't proliferate or give rise to other cell lineages. Consistent with previous reports, Trp63CreERT2 and KRT5-CreERT2 labeled ectopic EBCs do not exhibit alveolar regeneration potential. Intriguingly, when tamoxifen was administrated post viral infection, Trp63CreERT2 but not KRT5-CreERT2 labels islands of alveolar epithelial cells that are negative for EBC biomarkers. Furthermore, germline deletion of Trpm5 significantly increases the contribution of Trp63CreERT2 labeled cells to the alveolar epithelium. Although Trpm5 is known to regulate tuft cell development, complete ablation of tuft cell production fails to improve alveolar regeneration in Pou2f3-/- mice, implying that Trpm5 promotes alveolar epithelial regeneration through a mechanism independent of tuft cells.

PMID:36129169 | DOI:10.7554/eLife.78217

Categories: Literature Watch

Systemic IgG exposure and safety in patients with primary immunodeficiency: a randomized crossover study comparing a novel investigational wearable infusor versus the Crono pump

Wed, 2022-09-21 06:00

Immunotherapy. 2022 Sep 21. doi: 10.2217/imt-2022-0097. Online ahead of print.

ABSTRACT

Aim: A novel, Investigational Wearable Infusor (IWI) was evaluated in a randomized, controlled, crossover, open-label study to determine if its delivery of subcutaneous immunoglobulin (IgPro20) achieved a comparable area under the concentration-time curve (AUC) for immunoglobulin G (IgG) versus the Crono S-PID-50 infusion pump (CP). EudraCT: 2016-003798-16. Materials & methods: Patients with primary immunodeficiency (PID) were randomized to receive IgPro20 in Sequence 1 (CP/IWI) or 2 (IWI/CP). The primary end point was AUC for IgG during the final week of each 4-week period. Results: 23 patients were enrolled. Evaluation of area under the concentration-time curve from time 0 (pre-infusion) to 7 days after infusion (AUC0-7 days) (IWI: 1806 h*g/l; CP: 1829 h*g/l) and geometric mean ratio indicated comparable AUCs for IgG for both devices. Conclusion: Similar IgG exposure, indicated by AUC values, can be achieved with IgPro20 using the IWI or CP in PID.

PMID:36128795 | DOI:10.2217/imt-2022-0097

Categories: Literature Watch

Post-Transplantation Anemia and Risk of Death Following Lung Transplantation

Tue, 2022-09-20 06:00

Transplant Proc. 2022 Sep 17:S0041-1345(22)00508-5. doi: 10.1016/j.transproceed.2022.07.012. Online ahead of print.

ABSTRACT

BACKGROUND: Post-transplantation anemia (PTA) is frequent among solid organ transplant recipients and has been associated with increased morbidity and mortality. However, the prevalence and impact of PTA in lung transplant recipients is still not elucidated.

METHODS: We performed a retrospective cohort study of adult Danish lung transplant recipients between January 2010 and December 2019. The prevalence and severity of PTA were determined during the first three years post-transplantation. Associations between PTA and selected risk factors were established using uni- and multivariate logistic regression models.

RESULTS: A total of 278 patients were included. At one and three years post-lung transplantation the prevalence of PTA was 75% and 52%, respectively. Male sex was associated with increased odds of PTA at all time points (aOR ranging from 2.3, 95% CI 1.1-4.6, P = 0.02 to 5.9, 95% CI 2.6-14, P < .001). Cystic fibrosis was also associated with anemia at one-year post-transplantation (aOR 4.3, 95% CI 1.2-17, P = 0.03). We found no strong associations between PTA and renal function or viral infections. Excess mortality in recipients with moderate or severe anemia compared to patients with mild or no anemia was borderline statistically significant at one-year post-lung transplantation (aHR 2.0, 95% CI 0.9-4.4, P = 0.07).

DISCUSSION: Post-transplantation anemia is very common in Danish lung transplant recipients. Male sex and cystic fibrosis are independent risk factors for development of anemia. Further investigation on PTA, the underlying mechanisms, and its clinical impact is needed.

PMID:36127173 | DOI:10.1016/j.transproceed.2022.07.012

Categories: Literature Watch

Integrating specialist palliative care to improve care and reduce suffering: cystic fibrosis (InSPIRe:CF) - study protocol for a multicentre randomised clinical trial

Tue, 2022-09-20 06:00

BMJ Open Respir Res. 2022 Sep;9(1):e001381. doi: 10.1136/bmjresp-2022-001381.

ABSTRACT

INTRODUCTION: Cystic fibrosis (CF) is a life-limiting genetic disorder estimated to affect more than 160 000 individuals and their families worldwide. People living with CF commonly experience significant physical and emotional symptom burdens, disruptions to social roles and complex treatment decision making. While palliative care (PC) interventions have been shown to relieve many such burdens in other serious illnesses, no rigorous evidence exists for palliative care in CF. Thus, this study aims to compare the effect of specialist palliative care plus usual CF care vs usual CF care alone on patient quality of life.

METHODS AND ANALYSIS: This is a five-site, two-arm, partially masked, randomised superiority clinical trial. 264 adults with CF will be randomly assigned to usual CF care or usual CF care plus a longitudinal palliative care intervention delivered by a palliative care specialist. The trial's primary outcome is patient quality of life (measured with the Functional Assessment of Chronic Illness Therapy-Palliative care instrument). Secondary outcomes include symptom burden, satisfaction with care and healthcare utilisation. Outcomes will be measured at 12 months (primary endpoint) and 15 months (secondary endpoint). In addition, we will conduct qualitative interviews with patient participants, caregivers, and palliative care and CF care team members to explore perceptions of the intervention's impact and barriers and facilitators to dissemination.

ETHICS AND DISSEMINATION: Human subjects research ethics approval was obtained from all participating sites, and all study participants gave informed consent. We will publish the results of this trial in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER: ISRCTN53323164.

PMID:36126995 | DOI:10.1136/bmjresp-2022-001381

Categories: Literature Watch

Spray drying siRNA-lipid nanoparticles for dry powder pulmonary delivery

Tue, 2022-09-20 06:00

J Control Release. 2022 Sep 17:S0168-3659(22)00613-7. doi: 10.1016/j.jconrel.2022.09.021. Online ahead of print.

ABSTRACT

While all the siRNA drugs on the market target the liver, the lungs offer a variety of currently undruggable targets which could potentially be treated with RNA therapeutics. Hence, local, pulmonary delivery of RNA nanoparticles could finally enable delivery beyond the liver. The administration of RNA drugs via dry powder inhalers offers many advantages related to physical, chemical and microbial stability of RNA and nanosuspensions. The present study was therefore designed to test the feasibility of engineering spray dried lipid nanoparticle (LNP) powders. Spray drying was performed using 5% lactose solution (m/V), and the targets were set to obtain nanoparticle sizes after redispersion of spray-dried powders around 150 nm, a residual moisture level below 5%, and RNA loss below 15% at maintained RNA bioactivity. The LNPs consisted of an ionizable cationic lipid which is a sulfur-containing analog of DLin-MC3-DMA, a helper lipid, cholesterol, and PEG-DMG encapsulating siRNA. Prior to the spray drying, the latter process was simulated with a novel dual emission fluorescence spectroscopy method to preselect the highest possible drying temperature and excipient solution maintaining LNP integrity and stability. Through characterization of physicochemical and aerodynamic properties of the spray dried powders, administration criteria for delivery to the lower respiratory tract were fulfilled. Spray dried LNPs penetrated the lung mucus layer and maintained bioactivity for >90% protein downregulation with a confirmed safety profile in a lung adenocarcinoma cell line. Additionally, the spray dried LNPs successfully achieved up to 50% gene silencing of the house keeping gene GAPDH in ex vivo human precision-cut lung slices at without increasing cytokine levels. This study verifies the successful spray drying procedure of LNP-siRNA systems maintaining their integrity and mediating strong gene silencing efficiency on mRNA and protein levels both in vitro and ex vivo. The successful spray drying procedure of LNP-siRNA formulations in 5% lactose solution creates a novel siRNA-based therapy option to target respiratory diseases such as lung cancer, asthma, COPD, cystic fibrosis and viral infections.

PMID:36126785 | DOI:10.1016/j.jconrel.2022.09.021

Categories: Literature Watch

Role of computed tomography angiography in the evaluation of haemoptysis in children: Decoding the abnormal vessels

Tue, 2022-09-20 06:00

Indian J Med Res. 2022 Mar&Apr;155(3&4):356-363. doi: 10.4103/ijmr.IJMR_3271_20.

ABSTRACT

BACKGROUND & OBJECTIVES: Haemoptysis in children is potentially life-threatening. In most cases, the bleeding arises from the systemic circulation, and in 5-10 per cent of cases, it arises from the pulmonary circulation. The role of computed tomography angiography (CTA) in this setting is important. This study was undertaken (i) to study the role of single-phase split-bolus dual energy contrast-enhanced multidetector row CTA (DECTA) in the evaluation of haemoptysis in children; (ii) to analyze the patterns of abnormal vascular supply in the various aetiologies encountered.

METHODS: A retrospective study of 86 patients who underwent split bolus DECTA for the evaluation of haemoptysis was performed. Final diagnoses were categorized as normal computed tomography, active tuberculosis (TB), post-infectious sequelae, non-TB active infection, cystic fibrosis (CF), non-CF bronchiectasis, congenital heart disease (CHD), interstitial lung disease, vasculitis, pulmonary thromboembolism and idiopathic pulmonary haemosiderosis. Abnormal bronchial arteries (BAs) and non-bronchial systemic collateral arteries (NBSCs) were assessed for number and site and their correlation with underlying aetiologies.

RESULTS: A total of 86 patients (45 males, age from 0.3 to 18 yr, mean 13.88 yr) were included in the study; among these only two patients were less than five years of age. The most common cause of haemoptysis was active infection (n=30), followed by bronchiectasis (n=18), post-infectious sequelae (n=17) and CHD (n=7). One hundred and sixty five abnormal arteries were identified (108 BA and 57 NBSC), and were more marked in bronchiectasis group.

INTERPRETATION & CONCLUSIONS: Active infections and bronchiectasis are the most common causes of haemoptysis in children. While post-infectious sequelae are less common, in patients with haemoptysis, the presence of any abnormal arteries correlates with a more frequent diagnosis of bronchiectasis. NBSCs are more common in post-infectious sequelae and CHD.

PMID:36124510 | DOI:10.4103/ijmr.IJMR_3271_20

Categories: Literature Watch

Real-world feasibility of short-term, unsupervised home spirometry in CF

Tue, 2022-09-20 06:00

Pediatr Pulmonol. 2022 Sep 19. doi: 10.1002/ppul.26147. Online ahead of print.

ABSTRACT

OBJECTIVES: The objective of this work was to study the performance of two available home spirometers used by people with Cystic Fibrosis (CF) over a short-term period and to assess user experience.

STUDY DESIGN: This was a prospective observational study. Participants age 6 years and older were recruited to participate if they could complete acceptable spirometry in the clinic setting.

METHODS: Participants used either the NuvoAir Air Next or the ZEPHYRx MIR Spirobank Smart spirometer. They underwent a one-time virtual training session, then completed 2 weeks of daily spirometry followed by 2 months of weekly spirometry. Participants responded to surveys and completed a debrief interview to understand user experience. Statistical analysis examined feasibility, reliability, accuracy of each spirometer in an unsupervised, real-world setting.

RESULTS: We report high adherence (80% [95% CI 61%-92%]) to our study protocol in all session attempts, but lower rates of adherence after discarding sessions performed with inadequate technique (47% [95% CI 28%-66%] to 63% [95% CI 44%-80%]). We found high reliability of each device by analyzing day-to-day variability and good concordance to recent in-clinic testing ((NuvoAir r=0.91 [0.82-0.93]; ZEPHYRx r=0.70 [0.45-0.84]). Patient experience in this cohort was favorable with most reporting ease of use and reassurance knowing lung function was being tracked over time.

CONCLUSIONS: This real-world study showed good performance of two different available home spirometers used by children and adults with CF. While overall adherence was high, suboptimal technique reduced the total interpretable data, possibly limiting feasibility. Future work should focus on developing sustainable training and coaching programs to support the success of home spirometry in a CF chronic care model. This article is protected by copyright. All rights reserved.

PMID:36124390 | DOI:10.1002/ppul.26147

Categories: Literature Watch

Evaluation of Growth Hormone Deficiency in Children with Cystic Fibrosis

Tue, 2022-09-20 06:00

Adv Biomed Res. 2022 Jul 29;11:62. doi: 10.4103/abr.abr_285_20. eCollection 2022.

ABSTRACT

BACKGROUND: Due to chronic respiratory and gastrointestinal problems, growth failure is a common issue in patients with cystic fibrosis (CF). The present study aimed to investigate the prevalence of growth hormone deficiency (GHD) in CF children with stable gastrointestinal and respiratory conditions.

MATERIALS AND METHODS: In this study, the growth indicators of all 4-16-year-old children referred to two CF clinics were monitored over 3 years. Children without severe gastrointestinal or pulmonary symptoms with weight <3% percentile or whose height increase were two standard deviations below their expected height growth over 6 months were selected for the growth hormone (GH) stimulation test by clonidine and L-dopa test. Some of the children without CF, who were also referred for height growth disorders and matched the CF group, were considered the control group. They underwent the GH stimulation test, and the results were compared.

RESULTS: From 150 patients with CF, growth failure was observed in 24 patients with stable gastrointestinal and respiratory conditions; in 10 of them, the GH stimulation test was deficient. The prevalence of GHD was 6.6% in CF patients. In the control group of 30 children without CF, but with growth failure, the GH was deficient in nine cases, implying no significant difference with the case group (P = 0.37).

CONCLUSION: In our study, the prevalence of GHD was 6.6% in CF patients, whereas the prevalence GHD in the normal population of childhood is <1%. Therefore, further studies should be designed to investigate the cause of GHD in CF patients.

PMID:36124019 | PMC:PMC9482379 | DOI:10.4103/abr.abr_285_20

Categories: Literature Watch

Significance of Molecular Identification of Genomic Variants of Pseudomonas aeruginosa in Children with Cystic Fibrosis in Mexico

Mon, 2022-09-19 06:00

Arch Med Res. 2022 Sep 17:S0188-4409(22)00105-9. doi: 10.1016/j.arcmed.2022.09.002. Online ahead of print.

ABSTRACT

Pseudomonas aeruginosa is a significant cause of lung infections in patients with cystic fibrosis (CF). Pseudomonas produces a chronic infection that increases the morbidity and mortality in affected individuals. The rapid identification of Pseudomonas in these individuals enables conventional antimicrobial treatment to be started. However, over the years, treatment of P. aeruginosa has become problematic and very challenging due to their intrinsic and acquired antibiotic resistance. Microbiology plays an essential role in determining the antimicrobial susceptibility/resistance profiles of isolated strains, helping to optimize antimicrobial treatment for affected patients. In addition to the conventional susceptibility analysis, whole genome sequencing has emerged as a powerful tool for determining specific genomic variants, both in specific geographic areas and globally. Thus, molecular epidemiologic surveillance could help to establish a better treatment strategy and counter the spread of high-risk, P. aeruginosa variants among CF individuals.

PMID:36123225 | DOI:10.1016/j.arcmed.2022.09.002

Categories: Literature Watch

Lysosomal cathepsin D mediates endogenous mucin glycodomain catabolism in mammals

Mon, 2022-09-19 06:00

Proc Natl Acad Sci U S A. 2022 Sep 27;119(39):e2117105119. doi: 10.1073/pnas.2117105119. Epub 2022 Sep 19.

ABSTRACT

Mucins are functionally implicated in a range of human pathologies, including cystic fibrosis, influenza, bacterial endocarditis, gut dysbiosis, and cancer. These observations have motivated the study of mucin biosynthesis as well as the development of strategies for inhibition of mucin glycosylation. Mammalian pathways for mucin catabolism, however, have remained underexplored. The canonical view, derived from analysis of N-glycoproteins in human lysosomal storage disorders, is that glycan degradation and proteolysis occur sequentially. Here, we challenge this view by providing genetic and biochemical evidence supporting mammalian proteolysis of heavily O-glycosylated mucin domains without prior deglycosylation. Using activity screening coupled with mass spectrometry, we ascribed mucin-degrading activity in murine liver to the lysosomal protease cathepsin D. Glycoproteomics of substrates digested with purified human liver lysosomal cathepsin D provided direct evidence for proteolysis within densely O-glycosylated domains. Finally, knockout of cathepsin D in a murine model of the human lysosomal storage disorder neuronal ceroid lipofuscinosis 10 resulted in accumulation of mucins in liver-resident macrophages. Our findings imply that mucin-degrading activity is a component of endogenous pathways for glycoprotein catabolism in mammalian tissues.

PMID:36122205 | DOI:10.1073/pnas.2117105119

Categories: Literature Watch

Genome Capture Sequencing Selectively Enriches Bacterial DNA and Enables Genome-Wide Measurement of Intrastrain Genetic Diversity in Human Infections

Mon, 2022-09-19 06:00

mBio. 2022 Sep 19:e0142422. doi: 10.1128/mbio.01424-22. Online ahead of print.

ABSTRACT

Within-host evolution produces genetic diversity in bacterial strains that cause chronic human infections. However, the lack of facile methods to measure bacterial allelic variation in clinical samples has limited understanding of intrastrain diversity's effects on disease. Here, we report a new method termed genome capture sequencing (GenCap-Seq) in which users inexpensively make hybridization probes from genomic DNA or PCR amplicons to selectively enrich and sequence targeted bacterial DNA from clinical samples containing abundant human or nontarget bacterial DNA. GenCap-Seq enables accurate measurement of allele frequencies over targeted regions and is scalable from specific genes to entire genomes, including the strain-specific accessory genome. The method is effective with samples in which target DNA is rare and inhibitory and DNA-degrading substances are abundant, including human sputum and feces. In proof-of-principle experiments, we used GenCap-Seq to investigate the responses of diversified Pseudomonas aeruginosa populations chronically infecting the lungs of people with cystic fibrosis to in vivo antibiotic exposure, and we found that treatment consistently reduced intrastrain genomic diversity. In addition, analysis of gene-level allele frequency changes suggested that some genes without conventional resistance functions may be important for bacterial fitness during in vivo antibiotic exposure. GenCap-Seq's ability to scalably enrich targeted bacterial DNA from complex samples will enable studies on the effects of intrastrain and intraspecies diversity in human infectious disease. IMPORTANCE Genetic diversity evolves in bacterial strains during human infections and could affect disease manifestations and treatment resistance. However, the extent of diversity present in vivo and its changes over time are difficult to measure by conventional methods. We developed a novel approach, GenCap-Seq, to enrich microbial DNA from complex human samples like sputum and feces for genome-wide measurements of bacterial allelic diversity. The approach is inexpensive, scalable to encompass entire targeted genomes, and works in the presence of abundant untargeted nucleic acids and inhibiting substances. We used GenCap-Seq to investigate in vivo responses of diversified bacterial strains to antibiotic treatment. This method will enable new ideas about the effects of intrastrain diversity on human infections to be tested.

PMID:36121157 | DOI:10.1128/mbio.01424-22

Categories: Literature Watch

COPD and the modulation of CFTR by acute exposure to cigarette smoke

Mon, 2022-09-19 06:00

Am J Physiol Cell Physiol. 2022 Sep 19. doi: 10.1152/ajpcell.00356.2022. Online ahead of print.

ABSTRACT

Chronic obstructive lung disease (COPD) is a leading cause of death and cigarette smoke is the main risk factor. Detecting its earliest stages and preventing a decline in lung function are key goals. The pathogenesis of COPD is complex but has some similarities to cystic fibrosis (CF), a disease caused by mutations in the cftr gene. CF leads to chronic inflammation, abnormal mucus and cycles of infection. Cigarette smoke exposure also causes CFTR dysfunction, and it is probably not a coincidence that inflammation, mucus obstruction and infections are also characteristics of COPD, although the exacerbations can be quite different. We review here the acute effects of cigarette smoke on CFTR function and its potential role in COPD. Understanding CFTR regulation by cigarette smoke may identify novel drug targets and facilitate the development of therapeutics that reduce the progression and severity of COPD.

PMID:36121129 | DOI:10.1152/ajpcell.00356.2022

Categories: Literature Watch

ROHHAD syndrome without rapid-onset obesity: A diagnosis challenge

Mon, 2022-09-19 06:00

Front Pediatr. 2022 Aug 31;10:910099. doi: 10.3389/fped.2022.910099. eCollection 2022.

ABSTRACT

BACKGROUND: ROHHAD syndrome (Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation and Autonomic Dysregulation) is rare. Rapid-onset morbid obesity is usually the first recognizable sign of this syndrome, however a subset of patients develop ROHHAD syndrome without obesity. The prevalence of this entity is currently unknown. Alteration of respiratory control as well as dysautonomic disorders often have a fatal outcome, thus early recognition of this syndrome is essential.

MATERIAL AND METHODS: A retrospective, observational, multicenter study including all cases of ROHHAD without rapid-onset obesity diagnosed in France from 2000 to 2020.

RESULTS: Four patients were identified. Median age at diagnosis was 8 years 10 months. Median body mass index was 17.4 kg/m2. Signs of autonomic dysfunction presented first, followed by hypothalamic disorders. All four patients had sleep apnea syndrome. Hypoventilation led to the diagnosis. Three of the four children received ventilatory support, all four received hormone replacement therapy, and two received psychotropic treatment. One child in our cohort died at 2 years 10 months old. For the three surviving patients, median duration of follow-up was 7.4 years.

CONCLUSION: ROHHAD syndrome without rapid-onset obesity is a particular entity, appearing later than ROHHAD with obesity. This entity should be considered in the presence of dysautonomia disorders without brain damage. Likewise, the occurrence of a hypothalamic syndrome with no identified etiology requires a sleep study to search for apnea and hypoventilation. The identification of ROHHAD syndrome without rapid-onset obesity is a clinical challenge, with major implications for patient prognosis.

PMID:36120648 | PMC:PMC9471950 | DOI:10.3389/fped.2022.910099

Categories: Literature Watch

Mucus aberrant properties in CF: Insights from cells and animal models

Sun, 2022-09-18 06:00

J Cyst Fibros. 2022 Sep 15:S1569-1993(22)00656-7. doi: 10.1016/j.jcf.2022.08.019. Online ahead of print.

ABSTRACT

Cystic fibrosis (CF), an autosomal genetic disorder caused by the dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, is characterized by mucus accumulation in the lungs, the intestinal tract, and the pancreatic ducts. Mucins are high-molecular-weight glycoproteins that govern the biochemical and biophysical properties of mucus. In the CF lung, increased mucus viscoelasticity is associated with decreased mucociliary clearance and defects in host defense mechanisms. The link between defective ion channel and abnormal mucus properties has been investigated in studies involving cell and animal models. In this review article, we discuss recent progress toward understanding the different regions and cells that express CFTR in the airways and how mucus is produced and cleared from the lungs. In addition, we reflect on animal models that provided insights into the organization and the role of the mucin network and how mucus and antimicrobial activities act in concert to protect the lungs from invading pathogens.

PMID:36117114 | DOI:10.1016/j.jcf.2022.08.019

Categories: Literature Watch

'Gold-standard' field test is a non-sequitur

Sun, 2022-09-18 06:00

Pulmonology. 2022 Sep 15:S2531-0437(22)00207-0. doi: 10.1016/j.pulmoe.2022.07.016. Online ahead of print.

NO ABSTRACT

PMID:36117100 | DOI:10.1016/j.pulmoe.2022.07.016

Categories: Literature Watch

Withaferin A targets the membrane of Pseudomonas aeruginosa and mitigates the inflammation in zebrafish larvae; an in vitro and in vivo approach

Sun, 2022-09-18 06:00

Microb Pathog. 2022 Sep 15:105778. doi: 10.1016/j.micpath.2022.105778. Online ahead of print.

ABSTRACT

Infections due to multidrug-resistant Pseudomonas aeruginosa are prevalent among patients with cystic fibrosis. The emergence of antibiotic-resistant pathogens necessitated the development of novel low-risk natural antibacterial compounds. Herbal medicines are used from dates of the origin of mankind and still serve their purpose as therapeutic agents. We demonstrated the antibacterial activity of Withaferin A extracted from the traditional herb, ashwagandha or winter cherry (Withania somnifera). Withaferin A exhibits strong antibacterial activity against P. aeruginosa with a minimum inhibitory concentration of 60 μM and minimum bactericidal concentration of 80 μM. Results obtained from membrane stabilization assay and electron microscopic analysis showed that Withaferin A acts by damaging the cell membrane of P. aeruginosa. Additionally, we investigated oxidative stress and inflammatory response after Withaferin A treatment in P. aeruginosa infected zebrafish larvae model. The results indicate that the level of ROS, and its related lipid peroxidation and apoptosis were significantly reduced after treated with Withaferin A. Consequently, an increment in antioxidant enzymes level such as superoxide dismutase (SOD) and catalase (CAT) was observed. Macrophage localization experiment showed a smaller number of localized macrophages in zebrafish, which indicates the reduction in inflammatory response. In conclusion, Withaferin A could serve as an alternative natural product in the treatment of infections caused by P. aeruginosa.

PMID:36116607 | DOI:10.1016/j.micpath.2022.105778

Categories: Literature Watch

Hericium caput-medusae (Bull.:Fr.) Pers. fermentation concentrate polysaccharides improves intestinal bacteria by activating chloride channels and mucus secretion

Sat, 2022-09-17 06:00

J Ethnopharmacol. 2022 Sep 14:115721. doi: 10.1016/j.jep.2022.115721. Online ahead of print.

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: As a traditional edible fungus in China and many other Asian countries, Hericium caput-medusae (Bull. Fr.) Pers. is widely used to improve the health of the gastrointestinal tract. For example, the drug "Weilexin Granules" is mainly composed of H. caput-medusae (Bull. Fr.) Pers. fermentation concentrate. However, the mechanism of action remains to be elucidated.

AIMS OF THE STUDY: The purpose of this study was to assess whether polysaccharides from H. caput-medusae (Bull. Fr.) Pers. fermentation concentrate (HFP) exerts a gut protective effect and a regulatory effect on the intestinal microbiota through the chloride channels and mucus secretion.

MATERIALS AND METHODS: HFP was extracted, characterized and different concentrations of HFP (100, 200, 400 mg/kg) were administered to mice for 14 days. The changes in gut microbiota were observed via 16S high throughput sequencing. Short-chain fatty acids (SCFAs) was detected by GC-MS. AB-PAS staining was used to observe the secretion of mucus. The chloride channel activity and protein expression were verified by short-circuit current measurement and western blot.

RESULTS: HFP regulated the abundance of gut microbiota in mice, with increased levels of Ruminococcaceae and Lachnospiraceae and reduced proportions of Staphylococcus and Enterobacter. HFP enhanced mucus volume as well as increased intestinal fluid secretion by activating the chloride channels. In addition, short-circuit current experiments also proved that HFP activates Cl⁻ currents targeting cystic fibrosis transmembrane conductance regulator (CFTR) and Anoamin1 (ANO1).

CONCLUSION: In conclusion, HFP might increase intestinal fluid secretion by promoting Cl⁻ secretion, which in turn advanced mucus hydration as well as regulated gut microbiota to improve intestinal health. Therefore, H. caput-medusae (Bull. Fr.) Pers. could be potentially used in the regulation of intestinal secretion and microbes.

PMID:36115601 | DOI:10.1016/j.jep.2022.115721

Categories: Literature Watch

Pages