Int J Mol Sci. 2023 Jun 23;24(13):10538. doi: 10.3390/ijms241310538.

ABSTRACT

Over the last fifteen years, with the approval of the first molecular treatments, a breakthrough era has begun for patients with cystic fibrosis (CF), the rare genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). These molecules, known as CFTR modulators, have led to unprecedented improvements in the lung function and quality of life of most CF patients. However, the efficacy of these drugs is still suboptimal, and the clinical response is highly variable even among individuals bearing the same mutation. Furthermore, not all patients carrying rare CFTR mutations are eligible for CFTR modulator therapies, indicating the need for alternative and/or add-on therapeutic approaches. Because the second messenger 3',5'-cyclic adenosine monophosphate (cAMP) represents the primary trigger for CFTR activation and a major regulator of different steps of the life cycle of the channel, there is growing interest in devising ways to fine-tune the cAMP signaling pathway for therapeutic purposes. This review article summarizes current knowledge regarding the role of cAMP signalosomes, i.e., multiprotein complexes bringing together key enzymes of the cAMP pathway, in the regulation of CFTR function, and discusses how modulating this signaling cascade could be leveraged for therapeutic intervention in CF.

PMID:37445715 | DOI:10.3390/ijms241310538

Healthcare (Basel). 2023 Jul 4;11(13):1936. doi: 10.3390/healthcare11131936.

ABSTRACT

Since the onset of the coronavirus disease, COVID-19 pandemic, concern arose for those who might be at higher risk of a worse COVID-19 prognosis, such as those with cystic fibrosis (CF). In this context, we evaluated the features of hospitalized patients with CF due to severe acute respiratory infection (SARI) in Brazil and we also performed a systematic review including all the studies published from the beginning of the first case of COVID-19 (17 November 2019) to the date of this search (23 May 2022) which included, concomitantly, patients with CF and COVID-19 in the worldwide population. In our Brazilian data, we evaluated the period from December 2019 to March 2022, and we included 33 demographical and clinical patients' features. We classified the patients into groups: (G1) SARI due to another viral infection than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (23; 5.4%), (G2) SARI due to an unknown etiological agent (286; 67.1%), and (G3) SARI due to SARS-CoV-2 infection (117; 27.5%). The individuals in G3 tended to be older, especially over 50 years old, and presented a higher prevalence of dyspnea, peripheral capillary oxygen saturation (SpO2) <95%, and cardiopathy. The highest prevalence for intensive care unit (ICU) treatment (52; 44.4%) and invasive mechanical ventilation (29; 24.8%) was for patients in G3. Almost half of the patients in G3 died (51; 43.6%); in contrast, none in G1 died. However, we observed 43 (15.0%) deaths in G2. In addition, 12 (4.2%) and one (0.9%) death not associated with SARI occurred, respectively, in the G2 and G3. The patients who died due to SARS-CoV-2 infection had a higher frequency of SpO2 <95% (46; 90.2%), ICU treatment (34; 66.7%), and invasive mechanical ventilation (27; 52.9%) when compared to those who recovered. The systematic review comprised a total of 31 papers published as observational studies. These studies comprised 661,386 patients in total, including children, adults, and elderly age groups. However, only 19,150 (2.9%) patients were diagnosed with CF and, from these patients, 2523 (0.4%) were diagnosed with both CF and COVID-19. It was observed that the most common outcome was the need for hospitalization (n = 322 patients with CF), and the need for oxygen support (n = 139 patients with CF). One hundred patients with CF needed intensive care units, fifty patients needed non-invasive mechanical ventilation support, and only three patients were described as receiving invasive mechanical ventilation support. Deaths were described in 38 patients with CF. Importantly, lung-transplanted patients with CF represented an increased risk of death in one publication; in accordance, another study described that lung transplantation and moderate to severe lung disease were independent risk factors for severe outcomes after SARS-CoV-2 infection. In contrast with the literature, in conclusion, Brazilian patients in G3 presented a severe phenotype, even though most of the other studies did not observe worse outcomes in patients with CF and COVID-19.

PMID:37444770 | DOI:10.3390/healthcare11131936

Cells. 2023 Jul 1;12(13):1764. doi: 10.3390/cells12131764.

ABSTRACT

The deletion of phenylalanine at position 508 (F508del) produces a misfolded CFTR protein that is retained in the ER and degraded. The lack of normal CFTR channel activity is associated with chronic infection and inflammation which are the primary causes of declining lung function in Cystic Fibrosis (CF) patients. Moreover, LPS-dependent oxidative stress downregulates CFTR function in airway epithelial cells. Olive leaf extract (OLE) is used in traditional medicine for its effects, including anti-oxidant and anti-inflammatory ones. We found that OLE decreased the intracellular ROS levels in a dose-response manner in CFBE cells. Moreover, OLE attenuates the inflammatory response to LPS or IL-1β/TNFα stimulation, mimicking the infection and inflammatory status of CF patients, in CFBE and primary nasal epithelial (HNE) cells. Furthermore, we demonstrated that OLE restored the LPS-mediated decrease of TrikfaftaTM-dependent F508del-CFTR function in CFBE and HNE cultures. These findings provide strong evidence of OLE to prevent redox imbalance and inflammation that can cause chronic lung damage by enhancing the antioxidant activity and attenuating inflammation in CF airway epithelial cells. Additionally, OLE might be used in combination with CFTR modulators therapy to improve their efficacy in CF patients.

PMID:37443798 | DOI:10.3390/cells12131764

JAC Antimicrob Resist. 2023 Jul 11;5(4):dlad083. doi: 10.1093/jacamr/dlad083. eCollection 2023 Aug.

ABSTRACT

OBJECTIVES: Cystic fibrosis (CF) patients are often colonized with Pseudomonas aeruginosa. During treatment, P. aeruginosa can develop subpopulations exhibiting variable in vitro antimicrobial (ABX) susceptibility patterns. Heteroresistance (HR) may underlie reported discrepancies between in vitro susceptibility results and clinical responses to various ABXs. Here, we sought to examine the presence and nature of P. aeruginosa polyclonal HR (PHR) and monoclonal HR (MHR) to ceftolozane/tazobactam in isolates originating from CF pulmonary exacerbations.

METHODS: This was a single-centre, non-controlled study. Two hundred and forty-six P. aeruginosa isolates from 26 adult CF patients were included. PHR was defined as the presence of different ceftolozane/tazobactam minimum inhibitory concentration (MIC) values among P. aeruginosa isolates originating from a single patient specimen. Population analysis profiles (PAPs) were performed to assess the presence of MHR, defined as ≥4-fold change in the ceftolozane/tazobactam MIC from a single P. aeruginosa colony.

RESULTS: Sixteen of 26 patient specimens (62%) contained PHR P. aeruginosa populations. Of these 16 patients, 6 (23%) had specimens in which PHR P. aeruginosa isolates exhibited ceftolozane/tazobactam MICs with categorical differences (i.e. susceptible versus resistant) compared to results reported as part of routine care. One isolate, PSA 1311, demonstrated MHR. Canonical ceftolozane/tazobactam resistance genes were not found in the MHR isolates (MHR PSA 1311 or PHR PSA 6130).

CONCLUSIONS: Ceftolozane/tazobactam PHR exists among P. aeruginosa isolates in this work, and approximately a quarter of these populations contained isolates with ceftolozane/tazobactam susceptibiilty interpretations different from what was reported clinically, supporting concerns surrounding the utility of traditional susceptibility testing methodology in the setting of CF specimens. Genome sequencing of isolates with acquired MHR to ceftolozane/tazobactam revealed variants of unknown significance. Future work will be centred on determining the significance of these mutations to better understand these data in clinical context.

PMID:37441352 | PMC:PMC10333726 | DOI:10.1093/jacamr/dlad083

J Med Chem. 2023 Jul 13. doi: 10.1021/acs.jmedchem.3c00608. Online ahead of print.

ABSTRACT

In cystic fibrosis (CF), deletion of phenylalanine 508 (F508del) in the CF transmembrane conductance regulator (CFTR) is associated to misfolding and defective gating of the mutant channel. One of the most promising CF drug targets is the ubiquitin ligase RNF5, which promotes F508del-CFTR degradation. Recently, the first ever reported inhibitor of RNF5 was discovered, i.e., the 1,2,4-thiadiazol-5-ylidene inh-2. Here, we designed and synthesized a series of new analogues to explore the structure-activity relationships (SAR) of this class of compounds. SAR efforts ultimately led to compound 16, which showed a greater F508del-CFTR corrector activity than inh-2, good tolerability, and no toxic side effects. Analogue 16 increased the basal level of autophagy similar to what has been described with RNF5 silencing. Furthermore, co-treatment with 16 significantly improved the F508del-CFTR rescue induced by the triple combination elexacaftor/tezacaftor/ivacaftor in CFBE41o- cells. These findings validate the 1,2,4-thiadiazolylidene scaffold for the discovery of novel RNF5 inhibitors and provide evidence to pursue this unprecedented strategy for the treatment of CF.

PMID:37440686 | DOI:10.1021/acs.jmedchem.3c00608

J Heart Lung Transplant. 2023 Jul 10:S1053-2498(23)01929-0. doi: 10.1016/j.healun.2023.07.003. Online ahead of print.

ABSTRACT

BACKGROUND: Whether functional status is associated with survival to pediatric lung transplant is unknown. We hypothesized that completely dependent functional status at waitlist registration, defined using Lansky Play Performance Scale (LPPS), would be associated with worse outcomes.

METHODS: Retrospective cohort study of pediatric lung transplant registrants utilizing UNOS STAR files (2005-2020). Primary exposure was completely dependent functional status, defined as LPPS score of 10-40. Primary outcome was waitlist removal for death/deterioration with cause-specific Cox (CSHR) regression. Subdistribution hazard regression (Fine and Gray, SHR) was used for the secondary outcome of waitlist removal due to transplant/improvement with a competing risk of death/deterioration. Confounders included: sex, age, race, diagnosis, ventilator dependence, ECMO, year, and listing center volume.

RESULTS: 964 patients were included (63.5% ≥ 12 years, 50.2% cystic fibrosis [CF]). Median waitlist days was 95; 20.1% were removed for death/deterioration and 68.2% for transplant/improvement. Completely dependent functional status was associated with removal due to death/deterioration (adjusted CSHR 5.30 [95% CI 2.86-9.80]). This association was modified by age (interaction p=0.0102), with a larger effect for age ≥ 12 years, and particularly strong for CF. In the Fine and Gray model, completely dependent functional status did not affect the risk of removal due to transplant/improvement with a competing risk of death/deterioration (adjusted SHR 1.08 [95% CI 0.77-1.49]).

CONCLUSIONS: Pediatric lung transplant registrants with the worst functional status had worse pre-transplant outcomes, especially for adolescents and CF patients. Functional status at waitlist registration may be a modifiable risk factor to improve survival to lung transplant.

PMID:37437825 | DOI:10.1016/j.healun.2023.07.003

J Cyst Fibros. 2023 Jul 10:S1569-1993(23)00114-5. doi: 10.1016/j.jcf.2023.04.010. Online ahead of print.

ABSTRACT

BACKGROUND: Highly effective CFTR modulators improve nutritional status and are of particular importance among younger children experiencing rapid growth. This study was designed to examine CFTR modulator associated changes in nutritional and other extrapulmonary outcomes in children 4-24 months of age with ivacaftor treatment over 12 weeks.

METHODS: Children 4-24 months were recruited from US and Canadian CF Centers. Eligible children were ivacaftor naïve and approved to start therapy. Anthropometrics, diet, sleeping energy expenditure (SEE), nutrition biomarkers, pancreatic status, serum and fecal calprotectin, serum bile acids, plasma fatty acids were measured. Changes from baseline at 6 and 12 weeks were examined using mixed effects linear regression modeling.

RESULTS: Fifteen participants enrolled (40% male). Weight-for-age z-scores increased at 6 (p = 0.03) and 12 weeks ivacaftor therapy (p<0.001) compared to baseline. Plasma docosatetraenoic acid (DTA), total saturated fatty acids increased at 6 weeks (p = 0.02) and 12 weeks (p = 0.009). At 12 weeks, serum CO2 concentration decreased (p = 0.002), serum urea nitrogen increased (p = 0.01) and fecal elastase increased (p = 0.02) compared to baseline. Bile acids, deoxycholic acid increased (p = 0.03) and ursodeoxycholic acid decreased (p = 0.02) after 12 weeks. Plasma total fatty acids, palmitic acid, mead, and docosatetraenoic acid (DTA) increased after 12 weeks (p = 0.02, p = 0.002 and p = 0.04, respectively). Plasma total saturated fatty acids increased at 6 weeks (p = 0.02) and 12 weeks (p = 0.009). Dietary intake (p = 0.04) and percent kcal from protein (p = 0.04) increased after 12 weeks compared to baseline.

CONCLUSIONS: Overall, younger children experienced favorable changes in nutritional and growth status in the first 12 weeks of ivacaftor therapy.

PMID:37438197 | DOI:10.1016/j.jcf.2023.04.010

Biochemistry. 2023 Jul 12. doi: 10.1021/acs.biochem.3c00165. Online ahead of print.

ABSTRACT

Cystic fibrosis (CF) is a recessive genetic disease that is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The recent development of a class of drugs called "correctors", which repair the structure and function of mutant CFTR, has greatly enhanced the life expectancy of CF patients. These correctors target the most common disease causing CFTR mutant F508del and are exemplified by the FDA-approved VX-809. While one binding site of VX-809 to CFTR was recently elucidated by cryo-electron microscopy, four additional binding sites have been proposed in the literature and it has been theorized that VX-809 and structurally similar correctors may engage multiple CFTR binding sites. To explore these five binding sites, ensemble docking was performed on wild-type CFTR and the F508del mutant using a large library of structurally similar corrector drugs, including VX-809 (lumacaftor), VX-661 (tezacaftor), ABBV-2222 (galicaftor), and a host of other structurally related molecules. For wild-type CFTR, we find that only one site, located in membrane spanning domain 1 (MSD1), binds favorably to our ligand library. While this MSD1 site also binds our ligand library for F508del-CFTR, the F508del mutation also opens a binding site in nucleotide binding domain 1 (NBD1), which enables strong binding of our ligand library to this site. This NBD1 site in F508del-CFTR exhibits the strongest overall binding affinity for our library of corrector drugs. This data may serve to better understand the structural changes induced by mutation of CFTR and how correctors bind to the protein. Additionally, it may aid in the design of new, more effective CFTR corrector drugs.

PMID:37437308 | DOI:10.1021/acs.biochem.3c00165

Mol Ther Nucleic Acids. 2023 Jun 8;33:57-74. doi: 10.1016/j.omtn.2023.06.004. eCollection 2023 Sep 12.

ABSTRACT

Genome engineering has become more accessible thanks to the CRISPR-Cas9 gene-editing system. However, using this technology in synthetic organs called "organoids" is still very inefficient. This is due to the delivery methods for the CRISPR-Cas9 machinery, which include electroporation of CRISPR-Cas9 DNA, mRNA, or ribonucleoproteins containing the Cas9-gRNA complex. However, these procedures are quite toxic for the organoids. Here, we describe the use of the "nanoblade (NB)" technology, which outperformed by far gene-editing levels achieved to date for murine- and human tissue-derived organoids. We reached up to 75% of reporter gene knockout in organoids after treatment with NBs. Indeed, high-level NB-mediated knockout for the androgen receptor encoding gene and the cystic fibrosis transmembrane conductance regulator gene was achieved with single gRNA or dual gRNA containing NBs in murine prostate and colon organoids. Likewise, NBs achieved 20%-50% gene editing in human organoids. Most importantly, in contrast to other gene-editing methods, this was obtained without toxicity for the organoids. Only 4 weeks are required to obtain stable gene knockout in organoids and NBs simplify and allow rapid genome editing in organoids with little to no side effects including unwanted insertion/deletions in off-target sites thanks to transient Cas9/RNP expression.

PMID:37435135 | PMC:PMC10331042 | DOI:10.1016/j.omtn.2023.06.004

J Pediatr Gastroenterol Nutr. 2023 Jul 12. doi: 10.1097/MPG.0000000000003886. Online ahead of print.

ABSTRACT

OBJECTIVE: Poor nutrition in patients with cystic fibrosis (CF) has been associated with lower lung function and increased morbidity and mortality. Conversely, better nutritional status has been associated with improved pulmonary function and fewer CF-associated complications. There is no consensus regarding appetite stimulant therapy in patients with CF (pwCF). The primary objective of this study was to determine if the use of appetite stimulants was associated with weight changes in pediatric pwCF in the ambulatory care setting.

METHODS: This was a retrospective study that evaluated 62 pediatric pwCF who received cyproheptadine or mirtazapine for appetite stimulation for at least 6 consecutive months. Weight z-scores were collected for each patient at baseline, 3, 6, and 12 months of therapy, if available.

RESULTS: Increase in weight z-score after 3 months of therapy was statistically significant based on both univariable and multivariable models when evaluating the entire cohort. The adjusted mean difference for change in weight z-score was 0.33 (p< 0.001) from baseline to month 3. There was a statistically significant improvement in pulmonary function after 3 and 6 months of therapy.

CONCLUSIONS: Appetite stimulant therapy is associated with improvement in weight z-score in the first 3 months of treatment. Appetite stimulant therapy was associated with improvement in pulmonary function in the first 3 months of therapy, which supports the relationship between weight gain and improved pulmonary function in pwCF. These findings suggest that appetite stimulants contribute to weight gain in pediatric pwCF, particularly within the first 3 months of therapy.

PMID:37434282 | DOI:10.1097/MPG.0000000000003886

PLoS One. 2023 Jul 11;18(7):e0288002. doi: 10.1371/journal.pone.0288002. eCollection 2023.

ABSTRACT

Pseudomonas aeruginosa (PA) is known to chronically infect airways of people with cystic fibrosis (CF) by early adulthood. PA infections can lead to increased airway inflammation and lung tissue damage, ultimately contributing to decreased lung function and quality of life. Existing models of PA infection in vitro commonly utilize 1-6-hour time courses. However, these relatively early time points may not encompass downstream airway cell signaling in response to the chronic PA infections observed in people with cystic fibrosis. To fill this gap in knowledge, the aim of this study was to establish an in vitro model that allows for PA infection of CF bronchial epithelial cells, cultured at the air liquid interface, for 24 hours. Our model shows with an inoculum of 2 x 102 CFUs of PA for 24 hours pro-inflammatory markers such as interleukin 6 and interleukin 8 are upregulated with little decrease in CF bronchial epithelial cell survival or monolayer confluency. Additionally, immunoblotting for phosphorylated phospholipase C gamma, a well-known downstream protein of fibroblast growth factor receptor signaling, showed significantly elevated levels after 24 hours with PA infection that were not seen at earlier timepoints. Finally, inhibition of phospholipase C shows significant downregulation of interleukin 8. Our data suggest that this newly developed in vitro "prolonged PA infection model" recapitulates the elevated inflammatory markers observed in CF, without compromising cell survival. This extended period of PA growth on CF bronchial epithelial cells will have impact on further studies of cell signaling and microbiological studies that were not possible in previous models using shorter PA exposures.

PMID:37432929 | DOI:10.1371/journal.pone.0288002

mBio. 2023 Jul 11:e0117123. doi: 10.1128/mbio.01171-23. Online ahead of print.

ABSTRACT

The genetic disease cystic fibrosis (CF) frequently leads to chronic lung infections by bacteria and fungi. We identified three individuals with CF with persistent lung infections dominated by Clavispora (Candida) lusitaniae. Whole-genome sequencing analysis of multiple isolates from each infection found evidence for selection for mutants in the gene MRS4 in all three distinct lung-associated populations. In each population, we found one or two unfixed, non-synonymous mutations in MRS4 relative to the reference allele found in multiple environmental and clinical isolates including the type strain. Genetic and phenotypic analyses found that all evolved alleles led to loss of function (LOF) of Mrs4, a mitochondrial iron transporter. RNA-seq analyses found that Mrs4 variants with decreased activity led to increased expression of genes involved in iron acquisition mechanisms in both low iron and replete iron conditions. Furthermore, surface iron reductase activity and intracellular iron were much higher in strains with Mrs4 LOF variants. Parallel studies found that a subpopulation of a CF-associated Exophiala dermatitidis infection also had a non-synonymous LOF mutation in MRS4. Together, these data suggest that MRS4 mutations may be beneficial during chronic CF lung infections in diverse fungi, perhaps, for the purposes of adaptation to an iron-restricted environment with chronic infections. IMPORTANCE The identification of MRS4 mutations in Clavispora (Candida) lusitaniae and Exophiala dermatitidis in individuals with cystic fibrosis (CF) highlights a possible adaptive mechanism for fungi during chronic CF lung infections. The findings of this study suggest that loss of function of the mitochondrial iron transporter Mrs4 can lead to increased activity of iron acquisition mechanisms, which may be advantageous for fungi in iron-restricted environments during chronic infections. This study provides valuable information for researchers working toward a better understanding of the pathogenesis of chronic lung infections and more effective therapies to treat them.

PMID:37432019 | DOI:10.1128/mbio.01171-23

Cureus. 2023 Jun 9;15(6):e40185. doi: 10.7759/cureus.40185. eCollection 2023 Jun.

ABSTRACT

Cystic fibrosis (CF) is a genetic disease that affects the lung, pancreas, and other organs caused by the presence of biallelic CF-causing variants in the cystic fibrosis conductance regular gene (CFTR). CFTR variants can also be found in CFTR-related disorders (CFTR-RD), which present milder symptoms. Increasing access to next-generation sequencing has demonstrated that both CF and CFTR-RD have a broader array of genotypes than formerly thought. Here we present three patients who carry the most common CFTR pathogenic variant - F508del - but express a wide array of phenotypes. These cases open discussion on the role of concurrent variants in CFTR, the importance of early diagnosis and treatment, and the contribution of lifestyle factors in CF and CFTR-RD presentation.

PMID:37431359 | PMC:PMC10329848 | DOI:10.7759/cureus.40185

JAMA. 2023 Jul 10:e2311043. doi: 10.1001/jama.2023.11043. Online ahead of print.

ABSTRACT

IMPORTANCE: Immune dysregulation contributes to poorer outcomes in COVID-19.

OBJECTIVE: To investigate whether abatacept, cenicriviroc, or infliximab provides benefit when added to standard care for COVID-19 pneumonia.

DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-masked, placebo-controlled clinical trial using a master protocol to investigate immunomodulators added to standard care for treatment of participants hospitalized with COVID-19 pneumonia. The results of 3 substudies are reported from 95 hospitals at 85 clinical research sites in the US and Latin America. Hospitalized patients 18 years or older with confirmed SARS-CoV-2 infection within 14 days and evidence of pulmonary involvement underwent randomization between October 2020 and December 2021.

INTERVENTIONS: Single infusion of abatacept (10 mg/kg; maximum dose, 1000 mg) or infliximab (5 mg/kg) or a 28-day oral course of cenicriviroc (300-mg loading dose followed by 150 mg twice per day).

MAIN OUTCOMES AND MEASURES: The primary outcome was time to recovery by day 28 evaluated using an 8-point ordinal scale (higher scores indicate better health). Recovery was defined as the first day the participant scored at least 6 on the ordinal scale.

RESULTS: Of the 1971 participants randomized across the 3 substudies, the mean (SD) age was 54.8 (14.6) years and 1218 (61.8%) were men. The primary end point of time to recovery from COVID-19 pneumonia was not significantly different for abatacept (recovery rate ratio [RRR], 1.12 [95% CI, 0.98-1.28]; P = .09), cenicriviroc (RRR, 1.01 [95% CI, 0.86-1.18]; P = .94), or infliximab (RRR, 1.12 [95% CI, 0.99-1.28]; P = .08) compared with placebo. All-cause 28-day mortality was 11.0% for abatacept vs 15.1% for placebo (odds ratio [OR], 0.62 [95% CI, 0.41-0.94]), 13.8% for cenicriviroc vs 11.9% for placebo (OR, 1.18 [95% CI 0.72-1.94]), and 10.1% for infliximab vs 14.5% for placebo (OR, 0.59 [95% CI, 0.39-0.90]). Safety outcomes were comparable between active treatment and placebo, including secondary infections, in all 3 substudies.

CONCLUSIONS AND RELEVANCE: Time to recovery from COVID-19 pneumonia among hospitalized participants was not significantly different for abatacept, cenicriviroc, or infliximab vs placebo.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04593940.

PMID:37428480 | PMC:PMC10334296 | DOI:10.1001/jama.2023.11043

BMC Pulm Med. 2023 Jul 10;23(1):250. doi: 10.1186/s12890-023-02543-z.

ABSTRACT

BACKGROUND: Bronchiectasis is a widely prevalent airway disease characterized by airway dilatation and recurrent infections, that can lead to respiratory failure in severe cases. The etiology of bronchiectasis varies geographically, but there is a lack of published data examining its etiology specifically within the Middle Eastern population.

METHODS: We conducted a retrospective analysis of our bronchiectasis patient registry, extracting clinical and demographic characteristics from electronic medical records. Quantitative variables were presented as the median and interquartile range (IQR), while categorical variables were expressed as numbers and percentages. Statistical comparisons for continuous characteristics were performed using the t-test, and significance was determined by a p-value less than 0.05.

RESULTS: In total we analysed 260 records (63% female, 37% male), with median age of 58 years (interquartile range (IQR) 38-71), Body Mass Index (BMI) 25.8(IQR 22-30), forced expiratory volume in the first second (FEV1) %predicted 65 (IQR 43-79) and FEV1/forced vital capacity (FVC) 0.76 (0.67-0.86). Sixty-five cases (25%) were post-infectious in aetiology (excluding post-TB - n:27 10.4%). Forty-eight (18.5%) patients were labelled idiopathic, while Primary Ciliary Dyskinesia (PCD) accounted for 23 (8.8%) cases. Pseudomonas aeruginosa was the most common colonizing organism (32.7%), followed by Haemophilus influenzae (9.2%) and Methicillin-Sensitive Staphylococcus aureus(6.9%). At the time of review, 11 patients had died (median age, FEV %predicted, and bronchiectasis severity index (BSI) 59 years, 38% and 15.5 respectively), all due to respiratory failure, and as expected, all were classed severe on BSI. The BSI score was available for 109 patients, of which 31(28%) were classed mild, 29(27%) were moderate, and 49 (45%) were classed severe. The median BSI score was 8 (IQR 4-11). On dividing the patients according to obstructive vs. restrictive spirometry, we found that patients with FEV1/FVC < 0.70 had significantly higher BSI (10.1 vs. 6.9, p-value < 0.001) and that 8 out of the 11 deceased patients had FEV1/FVC < 70%.

CONCLUSIONS: In our study, post-infectious, idiopathic, and PCD were identified as the most common etiologies of bronchiectasis. Additionally, patients with obstructive spirometry appeared to have a worse prognosis compared to those with restrictive spirometry.

PMID:37430275 | DOI:10.1186/s12890-023-02543-z

J Cyst Fibros. 2023 Jul 8:S1569-1993(23)00828-7. doi: 10.1016/j.jcf.2023.06.014. Online ahead of print.

ABSTRACT

We describe a case of a 46-year-old woman with cystic fibrosis who presented with several days of abdominal pain and distension. She was found to have a small bowel obstruction with inspissated stool in the distal ileum on CT imaging. Despite initial management with conservative measures, her symptoms worsened. She was taken for urgent colonoscopy with administration of 4% N-acetylcysteine (NAC) and polyethylene glycol (PEG) at the distal ileum with resultant dissolution of the fecalith. Over the following days, her symptoms improved, and she was discharged with outpatient follow-up.

PMID:37429745 | DOI:10.1016/j.jcf.2023.06.014

Biomater Adv. 2023 Jun 28;153:213540. doi: 10.1016/j.bioadv.2023.213540. Online ahead of print.

ABSTRACT

Recurrent bacterial infections are a common cause of death for patients with cystic fibrosis and chronic obstructive pulmonary disease. Herein, we present the development of the degradable poly(sebacic acid) (PSA) microparticles loaded with different concentrations of azithromycin (AZ) as a potential powder formulation to deliver AZ locally to the lungs. We characterized microparticle size, morphology, zeta potential, encapsulation efficiency, interaction PSA with AZ and degradation profile in phosphate buffered saline (PBS). The antibacterial properties were evaluated using the Kirby-Bauer method against Staphylococcus aureus. Potential cytotoxicity was evaluated in BEAS-2B and A549 lung epithelial cells by the resazurin reduction assay and live/dead staining. The results show that microparticles are spherical and their size, being in the range of 1-5 μm, should be optimal for pulmonary delivery. The AZ encapsulation efficiency is nearly 100 % for all types of microparticles. The microparticles degradation rate is relatively fast - after 24 h their mass decreased by around 50 %. The antibacterial test showed that released AZ was able to successfully inhibit bacteria growth. The cytotoxicity test showed that the safe concentration of both unloaded and AZ-loaded microparticles was equal to 50 μg/ml. Thus, appropriate physicochemical properties, controlled degradation and drug release, cytocompatibility, and antibacterial behavior showed that our microparticles may be promising for the local treatment of lung infections.

PMID:37429048 | DOI:10.1016/j.bioadv.2023.213540

Microbiology (Reading). 2023 Jul;169(7). doi: 10.1099/mic.0.001361.

ABSTRACT

A workshop was held by the PIPE-CF strategic research centre to consider preclinical testing of antimicrobials for cystic fibrosis (CF). The workshop brought together groups of people from the CF community to discuss current challenges and identify priorities when developing CF therapeutics. This paper summarizes the key points from the workshop from the different sessions, including talks given by presenters on the day and round table discussions. Currently, it is felt that there is a large disconnect throughout the community, with communication between patients, clinicians and researchers being the main issue. This leads to little consideration being given to factors such as treatment regimes, routes of administration and side effects when developing new therapies, that could alter the day-to-day lifestyles of people living with CF. Translation of numerical data that are obtained in the laboratory to successful outcomes of clinical trials is also a key challenge facing researchers today. Laboratory assays in preclinical testing involve basing results on bacterial clearance and decrease in viable cells, when these are not factors that are considered when determining the success of a treatment in the clinic. However, there are several models currently in development that seek to tackle some of these issues, such as the organ-on-a-chip technology and adaptation of a hollow-fibre model, as well as the development of media that aim to mimic the niche environments of a CF respiratory tract. It is hoped that by summarizing these opinions and discussing current research, the communication gap between groups can begin to close.

PMID:37428539 | DOI:10.1099/mic.0.001361

Antimicrob Agents Chemother. 2023 Jul 10:e0041423. doi: 10.1128/aac.00414-23. Online ahead of print.

ABSTRACT

Pseudomonas aeruginosa remains a challenge in chronic respiratory infections in cystic fibrosis (CF). Ceftolozane-tazobactam has not yet been evaluated against multidrug-resistant hypermutable P. aeruginosa isolates in the hollow-fiber infection model (HFIM). Isolates CW41, CW35, and CW44 (ceftolozane-tazobactam MICs of 4, 4, and 2 mg/L, respectively) from adults with CF were exposed to simulated representative epithelial lining fluid pharmacokinetics of ceftolozane-tazobactam in the HFIM. Regimens were continuous infusion (CI; 4.5 g/day to 9 g/day, all isolates) and 1-h infusions (1.5 g every 8 hours and 3 g every 8 hours, CW41). Whole-genome sequencing and mechanism-based modeling were performed for CW41. CW41 (in four of five biological replicates) and CW44 harbored preexisting resistant subpopulations; CW35 did not. For replicates 1 to 4 of CW41 and CW44, 9 g/day CI decreased bacterial counts to <3 log10 CFU/mL for 24 to 48 h, followed by regrowth and resistance amplification. Replicate 5 of CW41 had no preexisting subpopulations and was suppressed below ~3 log10 CFU/mL for 120 h by 9 g/day CI, followed by resistant regrowth. Both CI regimens reduced CW35 bacterial counts to <1 log10 CFU/mL by 120 h without regrowth. These results corresponded with the presence or absence of preexisting resistant subpopulations and resistance-associated mutations at baseline. Mutations in ampC, algO, and mexY were identified following CW41 exposure to ceftolozane-tazobactam at 167 to 215 h. Mechanism-based modeling well described total and resistant bacterial counts. The findings highlight the impact of heteroresistance and baseline mutations on the effect of ceftolozane-tazobactam and limitations of MIC to predict bacterial outcomes. The resistance amplification in two of three isolates supports current guidelines that ceftolozane-tazobactam should be utilized together with another antibiotic against P. aeruginosa in CF.

PMID:37428034 | DOI:10.1128/aac.00414-23

bioRxiv. 2023 Jun 28:2023.06.26.546583. doi: 10.1101/2023.06.26.546583. Preprint.

ABSTRACT

Cystic fibrosis (CF) is a muco-obstructive lung disease where inflammatory responses due to chronic infection result in the accumulation of neutrophil extracellular traps (NETs) in the airways. NETs are web-like complexes comprised mainly of decondensed chromatin that function to capture and kill bacteria. Prior studies have established excess release of NETs in CF airways increases viscoelasticity of mucus secretions and reduces mucociliary clearance. Despite the pivotal role of NETs in CF disease pathogenesis, current in vitro models of this disease do not account for their contribution. Motivated by this, we developed a new approach to study the pathobiological effects of NETs in CF by combining synthetic NET-like biomaterials, composed of DNA and histones, with an in vitro human airway epithelial cell culture model. To determine the impact of synthetic NETs on airway clearance function, we incorporated synthetic NETs into mucin hydrogels and cell culture derived airway mucus to assess their rheological and transport properties. We found that the addition of synthetic NETs significantly increases mucin hydrogel and native mucus viscoelasticity. As a result, mucociliary transport in vitro was significantly reduced with the addition of mucus containing synthetic NETs. Given the prevalence of bacterial infection in the CF lung, we also evaluated the growth of Pseudomonas aeruginosa in mucus with or without synthetic NETs. We found mucus containing synthetic NETs promoted microcolony growth and prolonged bacterial survival. Together, this work establishes a new biomaterial enabled approach to study innate immunity mediated airway dysfunction in CF.

PMID:37425779 | PMC:PMC10327088 | DOI:10.1101/2023.06.26.546583