CPT Pharmacometrics Syst Pharmacol. 2022 Jun 24. doi: 10.1002/psp4.12832. Online ahead of print.

ABSTRACT

Cystic fibrosis has been linked to altered drug disposition in various studies. However, the magnitude of these changes, influencing factors and underlying mechanisms remain a matter of debate. The primary aim of this work was therefore to quantify changes in drug disposition (top-down) and the pathophysiological parameters known to affect pharmacokinetics (bottom-up). This was done through meta-analyses and meta-regressions in addition to theoretical pharmacokinetic simulations. Volumes of distribution and clearances were found to be elevated in people living with cystic fibrosis. These increases were larger in studies which included patients with pulmonary exacerbations. Differences in clearance were smaller in more recent studies and when results were normalized to body surface area or lean body mass instead of body weight. For the physiological parameters investigated, measured glomerular filtration rate and serum cytokine concentrations were found to be elevated in people living with cystic fibrosis, while serum albumin and creatinine levels were decreased. Possible pathophysiological mechanisms for these alterations relate to renal hyperfiltration, increases in free fraction and inflammation. No differences were detected for cardiac output, body fat, fat free mass, hematocrit, creatinine clearance and the activity of drug metabolizing enzymes. These findings imply that in general, lower total plasma concentrations of drugs can be expected in people living with cystic fibrosis, especially when pulmonary exacerbations are present. Given the potential effect of cystic fibrosis on plasma protein binding and the variability in outcome observed between studies, the clinical relevance of adapting existing dosage regimens should be evaluated on a case-by-case basis.

PMID:35748042 | DOI:10.1002/psp4.12832

ERJ Open Res. 2022 Jun 20;8(2):00068-2022. doi: 10.1183/23120541.00068-2022. eCollection 2022 Apr.

ABSTRACT

BACKGROUND: Obstructive sleep apnoea (OSA) is a common chronic condition that is associated with significant morbidity and economic cost. Prolonged wait times are increasingly being recognised as a barrier to diagnosis and treatment of many chronic diseases; however, no study to date has prospectively evaluated the impact of wait times on health outcomes in OSA.

OBJECTIVE: The purpose of this study is to determine whether treatment outcomes for individuals with OSA differ between patients managed using an expedited versus standard pathway.

METHODS: A pragmatic randomised controlled trial design will be used with a target sample size of 200 adults. Participants with clinically significant uncomplicated OSA will be recruited through referrals to a large tertiary care sleep centre (Calgary, AB, Canada) and randomised to either early management (within 1 month) or usual care (∼6 months) with a 1:1 allocation using a concealed computer-generated randomisation sequence. The primary outcome will be adherence to positive airway pressure (PAP) therapy at 3 months after treatment initiation. Secondary outcomes will include change in sleepiness, quality of life, patient satisfaction, and patient engagement with therapy from baseline to 3 months after PAP initiation, measured using validated questionnaires and qualitative methods.

ANTICIPATED RESULTS: This study will determine whether expedited care for OSA leads to differences in PAP adherence and/or patient-reported outcomes. More broadly, the findings of this study may improve the understanding of how wait time reductions impact health outcomes for other chronic diseases.

PMID:35747231 | PMC:PMC9209848 | DOI:10.1183/23120541.00068-2022

J Clin Transl Endocrinol. 2022 Jun 14;29:100301. doi: 10.1016/j.jcte.2022.100301. eCollection 2022 Sep.

ABSTRACT

Cystic fibrosis (CF) is an autosomal recessive disorder, with a prevalence of 1 in 2,500 live births. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. With the significant advancement in CFTR-directed therapies, life expectancy of CF patients has steadily increased. With improved survival, CF related co-morbidities have become more apparent. The most common endocrine complication includes Cystic fibrosis related diabetes (CFRD). Impaired glucose tolerance and insulin deficiency in CFRD leads to a decline in pulmonary function in CF patients. Here we review the underlying mechanisms involved in the pathogenesis of CFRD, focusing on the role of CFTR in the regulation of insulin secretion from the β-cell. We then discuss CFTR modulators and their effect on impaired glucose tolerance and CFRD.

PMID:35746945 | PMC:PMC9209718 | DOI:10.1016/j.jcte.2022.100301

Microorganisms. 2022 Jun 18;10(6):1247. doi: 10.3390/microorganisms10061247.

ABSTRACT

Bacteria use a cell-cell communication process called quorum sensing (QS) to orchestrate collective behaviors. QS relies on the group-wide detection of extracellular signal molecules called autoinducers (AI). Quorum sensing is required for virulence and biofilm formation in the human pathogen Pseudomonas aeruginosa. In P. aeruginosa, LasR and RhlR are homologous LuxR-type soluble transcription factor receptors that bind their cognate AIs and activate the expression of genes encoding functions required for virulence and biofilm formation. While some bacterial signal transduction pathways follow a linear circuit, as phosphoryl groups are passed from one carrier protein to another ultimately resulting in up- or down-regulation of target genes, the QS system in P. aeruginosa is a dense network of receptors and regulators with interconnecting regulatory systems and outputs. Once activated, it is not understood how LasR and RhlR establish their signaling hierarchy, nor is it clear how these pathway connections are regulated, resulting in chronic infection. Here, we reviewed the mechanisms of QS progression as it relates to bacterial pathogenesis and antimicrobial resistance and tolerance.

PMID:35744765 | DOI:10.3390/microorganisms10061247

Microorganisms. 2022 Jun 6;10(6):1164. doi: 10.3390/microorganisms10061164.

ABSTRACT

The physiology of an organism in the environment reflects its interactions with the diverse physical, chemical, and biological properties of the surface. These principles come into consideration during model selection to study biofilm-host interactions. Biofilms are communities formed by beneficial and pathogenic bacteria, where cells are held together by a structured extracellular matrix. When biofilms are associated with a host, chemical gradients and their origins become highly relevant. Conventional biofilm laboratory models such as multiwall biofilm models and agar plate models poorly mimic these gradients. In contrast, ex vivo models possess the partial capacity to mimic the conditions of tissue-associated biofilm and a biofilm associated with a mineralized surface enriched in inorganic components, such as the human dentin. This review will highlight the progress achieved using these settings for two models of persistent infections: the infection of the lung tissue by Pseudomonas aeruginosa and the infection of the root canal by Enterococcus faecalis. For both models, we conclude that the limitations of the conventional in vitro systems necessitate a complimentary experimentation with clinically relevant ex vivo models during therapeutics development.

PMID:35744683 | DOI:10.3390/microorganisms10061164

Life (Basel). 2022 Jun 15;12(6):898. doi: 10.3390/life12060898.

ABSTRACT

BACKGROUND: Acute cellular rejection (ACR) is a complication after lung transplantation (LTx). The diagnosis of ACR is based on histologic findings using transbronchial forceps biopsy (FB). However, its diagnostic accuracy is limited because of the small biopsy size and crush artifacts. Transbronchial cryobiopsy (CB) provides a larger tissue size compared with FB.

METHODS: FB and CB were obtained consecutively during the same bronchoscopy (February 2020-April 2021). All biopsies were scored according to the ISHLT criteria by three pathologists. Interobserver agreement was scored by the kappa index. We assessed the severity of bleeding and the presence of pneumothorax.

RESULTS: In total, 35 lung transplant recipients were included, and 126 CBs and 315 FBs were performed in 63 consecutive bronchoscopies. ACR (A1-A3, minimal-moderate) was detected in 18 cases (28.6%) by CB, whereas ACR was detected in 3 cases (4.8%) by FB. Moderate and severe bleeding complicated FB and CB procedures in 23 cases (36.5%) and 1 case (1.6%), respectively. Pneumothorax occurred in 6.3% of patients. The interobserver agreement was comparable for both CB and FB.

CONCLUSIONS: CB provided an improved diagnostic yield for ACR diagnosis, leading to reclassification and changes in treatment strategies in 28.6% of cases. Prospective studies should better define the role of CB after LTx.

PMID:35743931 | DOI:10.3390/life12060898

J Pers Med. 2022 May 25;12(6):868. doi: 10.3390/jpm12060868.

ABSTRACT

Cystic Fibrosis (CF) is a disease caused by mutations in the CFTR gene that severely affects the lungs as well as extra-pulmonary tissues, including the gastrointestinal (GI) tract. CFTR dysfunction resulting from either mutations or the downregulation of its expression has been shown to promote carcinogenesis. An example is the enhanced risk for several types of cancer in patients with CF, especially cancers of the GI tract. CFTR also acts as a tumor suppressor in diverse sporadic epithelial cancers in many tissues, primarily due to the silencing of CFTR expression via multiple mechanisms, but especially due to epigenetic regulation. This review provides an update on the latest research linking CFTR-deficiency to GI cancers, in both CF patients and in sporadic GI cancers, with a particular focus on cancer of the intestinal tract. It will discuss changes in the tissue landscape linked to CFTR-deficiency that may promote cancer development such as breakdowns in physical barriers, microbial dysbiosis and inflammation. It will also discuss molecular pathways and mechanisms that act upstream to modulate CFTR expression, such as by epigenetic silencing, as well as molecular pathways that act downstream of CFTR-deficiency, such as the dysregulation of the Wnt/β-catenin and NF-κB signaling pathways. Finally, it will discuss the emerging CFTR modulator drugs that have shown promising results in improving CFTR function in CF patients. The potential impact of these modulator drugs on the treatment and prevention of GI cancers can provide a new example of personalized cancer medicine.

PMID:35743652 | DOI:10.3390/jpm12060868

Int J Mol Sci. 2022 Jun 8;23(12):6400. doi: 10.3390/ijms23126400.

ABSTRACT

In the lung, glycosaminoglycans (GAGs) are dispersed in the extracellular matrix (ECM) occupying the interstitial space between the capillary endothelium and the alveolar epithelium, in the sub-epithelial tissue and in airway secretions. In addition to playing key structural roles, GAGs contribute to a number of physiologic processes ranging from cell differentiation, cell adhesion and wound healing. Cytokine and chemokine-GAG interactions are also involved in presentation of inflammatory molecules to respective receptors leading to immune cell migration and airway infiltration. More recently, pathophysiological roles of GAGs have been described. This review aims to discuss the biological roles and molecular interactions of GAGs, and their impact in the pathology of chronic airway diseases, such as cystic fibrosis and chronic obstructive pulmonary disease. Moreover, the role of GAGs in respiratory disease has been heightened by the current COVID-19 pandemic. This review underlines the essential need for continued research aimed at exploring the contribution of GAGs in the development of inflammation, to provide a better understanding of their biological impact, as well as leads in the development of new therapeutic agents.

PMID:35742845 | DOI:10.3390/ijms23126400

Int J Environ Res Public Health. 2022 Jun 10;19(12):7133. doi: 10.3390/ijerph19127133.

ABSTRACT

The aim of this study was to compare the use of generic and cystic fibrosis (CF)-specific cut-points to assess movement behaviours in children and adolescents with CF. Physical activity (PA) was assessed for seven consecutive days using a non-dominant wrist-worn ActiGraph GT9X in 71 children and adolescents (36 girls; 13.5 ± 2.9 years) with mild CF. CF-specific and generic Euclidean norm minus one (ENMO) cut-points were used to determine sedentary time (SED), sleep, light physical activity (LPA), moderate physical activity and vigorous physical activity. The effect of using a CF-specific or generic cut-point on the relationship between PA intensities and lung function was determined. Movement behaviours differed significantly according to the cut-point used, with the CF-specific cut-points resulting in less time asleep (-31.4 min; p < 0.01) and in LPA (-195.1 min; p < 0.001), and more SED and moderate-to-vigorous PA (159.3 and 67.1 min, respectively; both p < 0.0001) than the generic thresholds. Lung function was significantly associated with LPA according to the CF-specific cut-points (r = 0.52; p = 0.04). Thresholds developed for healthy populations misclassified PA levels, sleep and SED in children and adolescents with CF. This discrepancy affected the relationship between lung function and PA, which was only apparent when using the CF-specific cut-points. Promoting LPA seems a promising strategy to enhance lung function in children and adolescents with CF.

PMID:35742382 | DOI:10.3390/ijerph19127133

Healthcare (Basel). 2022 Jun 1;10(6):1023. doi: 10.3390/healthcare10061023.

ABSTRACT

Vitamin D (VD) is an essential micronutrient with multiple functions for human growth, and adequate intake should be guaranteed throughout life. However, VD insufficiency is observed in infants all over the world. Low VD concentration in the breast milk of non-supplemented mothers and low compliance to VD daily supplementation are the main causes of VD insufficiency, especially in the long term. Furthermore, VD supplementation dosages are still debated and differ by country. We conducted a systematic review to compare the most recent evidence on different postnatal VD supplementation strategies, determining whether supplementation given to the mother is as effective as that administered directly to the child, and whether different dosages and administration schedules differ significantly in terms of efficacy and safety. We identified 18 randomized controlled trials (RCTs) addressing the role of infant (n = 961), maternal (n = 652) or combined infant and maternal VD supplementation (n = 260 pairs). In all studies, similar outcomes emerged in terms of efficacy and safety. According to our findings, alternative approaches of VD supplementation may be adopted, especially in cases where the adherence to daily supplementation strategies is poor. This review shows that different dosages and supplementation strategies result in similar VD sufficiency rates. Therefore, international guidelines may be revised in the future to offer multiple and different options of supplementation for specific settings and ages.

PMID:35742074 | DOI:10.3390/healthcare10061023

Cells. 2022 Jun 16;11(12):1938. doi: 10.3390/cells11121938.

ABSTRACT

BACKGROUND: Cystic Fibrosis (CF) is a genetic disorder affecting around 1 in every 3000 newborns. In the most common mutation, F508del, the defective anion channel, CFTR, is prevented from reaching the plasma membrane (PM) by the quality check control of the cell. Little is known about how CFTR pharmacological rescue impacts the cell proteome.

METHODS: We used high-resolution mass spectrometry, differential ultracentrifugation, machine learning and bioinformatics to investigate both changes in the expression and localization of the human bronchial epithelium CF model (F508del-CFTR CFBE41o-) proteome following treatment with VX-809 (Lumacaftor), a drug able to improve the trafficking of CFTR.

RESULTS: The data suggested no stark changes in protein expression, yet subtle localization changes of proteins of the mitochondria and peroxisomes were detected. We then used high-content confocal microscopy to further investigate the morphological and compositional changes of peroxisomes and mitochondria under these conditions, as well as in patient-derived primary cells. We profiled several thousand proteins and we determined the subcellular localization data for around 5000 of them using the LOPIT-DC spatial proteomics protocol.

CONCLUSIONS: We observed that treatment with VX-809 induces extensive structural and functional remodelling of mitochondria and peroxisomes that resemble the phenotype of healthy cells. Our data suggest additional rescue mechanisms of VX-809 beyond the correction of aberrant folding of F508del-CFTR and subsequent trafficking to the PM.

PMID:35741067 | DOI:10.3390/cells11121938

Cells. 2022 Jun 8;11(12):1868. doi: 10.3390/cells11121868.

ABSTRACT

Cystic fibrosis (CF) is the most common monogenic disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Over the last 30 years, tremendous progress has been made in understanding the molecular basis of CF and the development of treatments that target the underlying defects in CF. Currently, a highly effective CFTR modulator treatment (Kalydeco™/Trikafta™) is available for 90% of people with CF. In this review, we will give an extensive overview of past and ongoing efforts in the development of therapies targeting the molecular defects in CF. We will discuss strategies targeting the CFTR protein (i.e., CFTR modulators such as correctors and potentiators), its cellular environment (i.e., proteostasis modulation, stabilization at the plasma membrane), the CFTR mRNA (i.e., amplifiers, nonsense mediated mRNA decay suppressors, translational readthrough inducing drugs) or the CFTR gene (gene therapies). Finally, we will focus on how these efforts can be applied to the 15% of people with CF for whom no causal therapy is available yet.

PMID:35740997 | DOI:10.3390/cells11121868

Children (Basel). 2022 Jun 18;9(6):915. doi: 10.3390/children9060915.

ABSTRACT

As with the majority of chronic diseases having specific nutrition recommendations, in cystic fibrosis (CF), the emphasis placed on patients regarding their diet and ideal body weight status often increases the risk of developing disordered eating behaviors and by inference, eating disorders (EDs). Body weight appears to be an important concern for patients with CF, with many patients struggling to lose weight. Between sexes, women appear more preoccupied with dieting compared to men, but exhibit a better body image, mainly due to their preference for a lower weight. Several comorbidities appear to change these dynamics, and visibly apparent factors, including scars, ports, and tubes, and the need for supplementary oxygen supply, may also influence body image perception. Disordered eating is usually initiated during a bout of pulmonary infection, with the patient feeling unwell to eat. Regarding the prevalence of EDs, research appears conflicting on whether it is higher among individuals with a CF diagnosis or not. As for comorbidities, anxiety and depression consist of the most common psychiatric diagnoses in CF, also greatly prevalent in EDs. Despite the plethora of studies, non-specific CF tools, small samples, and lack of data regarding important outcomes, including lung health, indicate the need for more research.

PMID:35740852 | DOI:10.3390/children9060915

Biomedicines. 2022 Jun 14;10(6):1408. doi: 10.3390/biomedicines10061408.

ABSTRACT

Despite following a gluten-free diet, which is currently the only effective therapy for celiac disease, about 5% of patients can develop serious complications, which in the case of refractory type 2 could evolve towards intestinal lymphoma. In this study, we have identified a set of 15 microRNAs in serum discriminating between the two types of refractory disease. Upregulated miR-770-5p, miR-181b-2-3p, miR-1193, and miR-1226-3p could be useful for the better stratification of patients and the monitoring of disease development, while miR-490-3p was found to be dysregulated in patients with refractory type 1. Finally, by using bioinformatic tools applied to the analysis of the targets of dysregulated microRNAs, we have completed a more precise assessment of their functions. These mainly include the pathway of response to Transforming Growth Factor β cell-cell signaling by Wnt; epigenetic regulation, especially novel networks associated with transcriptional and post-transcriptional alterations; and the well-known inflammatory profiles.

PMID:35740429 | DOI:10.3390/biomedicines10061408

Nat Commun. 2022 Jun 23;13(1):3586. doi: 10.1038/s41467-022-31206-6.

ABSTRACT

Impaired activity of the chloride channel CFTR is the cause of cystic fibrosis. 14-3-3 proteins have been shown to stabilize CFTR and increase its biogenesis and activity. Here, we report the identification and mechanism of action of a macrocycle stabilizing the 14-3-3/CFTR complex. This molecule rescues plasma membrane localization and chloride transport of F508del-CFTR and works additively with the CFTR pharmacological chaperone corrector lumacaftor (VX-809) and the triple combination Trikafta®. This macrocycle is a useful tool to study the CFTR/14-3-3 interaction and the potential of molecular glues in cystic fibrosis therapeutics.

PMID:35739107 | DOI:10.1038/s41467-022-31206-6

Rev Mal Respir. 2022 Jun 20:S0761-8425(22)00204-2. doi: 10.1016/j.rmr.2022.05.001. Online ahead of print.

ABSTRACT

Congestion of the upper (URT) and lower respiratory tracts (LRT) is a common symptom in several acute and chronic respiratory diseases that occur in childhood. To eliminate these secretions, airway clearance techniques (ACT) directed to the URT and LRT are frequently prescribed. The rationale for the application of these techniques is the same as in adults, but they need to be adapted to be transposed to children. The physiotherapist will be able to choose among a wide range of techniques, of which the most adequate will depend not only on the age of the child and the indication, but also on the basis of his preferences or habits, as well as those of the child. Upper airway clearance, including nasal irrigation, is now recommended for acute and chronic rhinosinusitis in children. It is also one of the symptomatic treatments recommended for infants with acute bronchiolitis. For LRT clearance, several indications, such as cystic fibrosis, primary ciliary dyskinesia and neuromuscular disease, are now widely advocated. Conversely, other indications, such as for infants with acute viral bronchiolitis, are highly controversial. Thoughtful application of these techniques is lacking in robust and precise tools to objectively assess the presence of bronchial congestion, and to treat it accordingly. Similarly, no precise and reliable evaluation of the effectiveness of these ACTs is available to date. This review is designed to explore the ACTs used by physiotherapists, to provide an overview of their current indications, and to consider complementary approaches.

PMID:35738979 | DOI:10.1016/j.rmr.2022.05.001

J Manag Care Spec Pharm. 2022 Jul;28(7):721-731. doi: 10.18553/jmcp.2022.28.7.721.

ABSTRACT

BACKGROUND: Cystic fibrosis (CF) is a rare, life-threatening disease that results in severe respiratory, digestive, and metabolic problems. Elexacaftor/tezacaftor/ivacaftor is an oral drug that was approved by the US Food and Drug Administration (FDA) on October 21, 2019, after demonstrating clinical improvements compared with previous CF transmembrane conductance regulator modulators. Use of CF transmembrane conductance regulator modulators has improved CF care, but their high costs exceed commonly used cost-effectiveness thresholds. The Institute for Clinical and Economic Review issued an access and affordability alert warning that these high costs could threaten sustainable access to high-value care. There exists little real-world evidence on the uptake of elexacaftor/tezacaftor/ivacaftor and the impact on total cost of care and other health care resource utilization. This exploratory study analyzed the uptake and total cost-of-care impact of elexacaftor/tezacaftor/ivacaftor using pharmacy and medical claims data in a commercially insured patient population. OBJECTIVE: To analyze the uptake of elexacaftor/tezacaftor/ivacaftor by members who qualified for treatment and to evaluate the differences in total cost of care and health care resource utilization in members who started treatment with elexacaftor/tezacaftor/ivacaftor. METHODS: Uptake and per-member per-month information was obtained from Prime Therapeutics databases using cystic fibrosis transmembrane conductance regulator (CFTR) modulator claims. The total cost-of-care and resource utilization analysis used pharmacy and medical claims from Prime Therapeutics and Blue Cross NC across approximately 1.34 million commercially insured members over 20 months. Members with CF were identified by 2 or more International Classification of Diseases, Tenth Revision codes (E84.xx) in any field at least 30 days apart or by a CFTR modulator claim. Only continuously enrolled members with CF with an elexacaftor/tezacaftor/ivacaftor pharmacy claim were included. The date of the first claim served as the index date. RESULTS: At 12 months after FDA approval, 77 (68%) Blue Cross NC members with CF were using elexacaftor/tezacaftor/ivacaftor. Of these, 33 had switched from a different CFTR modulator and 44 were naive to CFTR modulator therapy. Pharmacy and medical claims for 51 continuously enrolled members that initiated elexacaftor/tezacaftor/ivacaftor were analyzed. The average total cost of care increased by 52% (P < 0.00001). Hospitalizations decreased from an average of 7.7 (± 7.2) to 3.9 (± 5.5) (P < 0.00001). The sum and average number of Pseudomonas aeruginosa infections were numerically lower, but the results did not meet statistical significance. Use of other supportive medications was numerically lower, but no statistically significant differences were observed. CONCLUSIONS: The uptake of elexacaftor/tezacaftor/ivacaftor was rapid, and the total cost of care increased despite reductions in hospitalizations and nonpharmacy costs. Differences in use of other CF-related medications appeared to be minimally affected. DISCLOSURES: Dr Smith and Dr Borchardt have no financial conflicts of interest to report. Both authors are employed at BCBSNC at the time of writing. The project had no outside funding or sponsorship. The majority of the work and data analysis was completed as part of the requirements of the PGY1 Managed Care Pharmacy Residency program at BCBSNC during the 2020-2021 cycle year. This research does not meet the definition of human subject research as defined by the US Department of Health and Human Services at 45 C.F.R. § 46.102(f). According to definitions in section (e)(1), our research did not require either (i) information or biospecimens through intervention or interaction with any individuals or (ii) obtained, used, studied, analyzed, or generated private information or identifiable biospecimens. Therefore, institutional review board approval or a valid exemption is not required.

PMID:35737861 | DOI:10.18553/jmcp.2022.28.7.721

PLoS One. 2022 Jun 23;17(6):e0270393. doi: 10.1371/journal.pone.0270393. eCollection 2022.

ABSTRACT

Patients with cystic fibrosis (CF) often suffer recurrent bronchial bacterial infections that lead to deterioration of lung function over time. The infections in CF patients are often due to S. aureus and P. aeruginosa that colonize the airways. Significantly, methicillin-resistant S. aureus (MRSA) makes it challenging for treatment in CF patients due to its feature of multiple antibiotic resistance. In bronchial airways, cationic antimicrobial peptides are often present in mucosa cells, neutrophils, and macrophages that interfere with bacterial proliferation. The major mechanism for resistance to the bactericidal activity of cationic peptides in S. aureus is mediated by the GraRS two-component system that activates expression of MprF and DltABCD to increase surface positive charge to repel interactions with cationic peptides. We recently found that VraG, a membrane permease component of the VraFG efflux pumps, harbors a long 200-residue extracellular loop (EL) that utilizes K380 to interact with the negatively charged 9-residue extracellular loop of the membrane sensor GraS to control mprF expression in a community-acquired MRSA strain JE2. In this study, we extended this observation to a CF MRSA strain CF32A1 where we affirmed that the EL loop of VraG controls GraS-mediated signal transduction; however, in contrast to community acquired MRSA strain JE2, the CF MRSA strain CF32A1 requires both K380 and K388 in the EL of VraG to properly modulate signal transduction mediated by GraS. This effect was not attributable to the several single nucleotide polymorphisms that exist between VraG and GraS in the two MRSA strains.

PMID:35737676 | DOI:10.1371/journal.pone.0270393

Microbiol Spectr. 2022 Jun 23:e0100622. doi: 10.1128/spectrum.01006-22. Online ahead of print.

ABSTRACT

Chronic colonization by Pseudomonas aeruginosa is critical in cystic fibrosis (CF) and other chronic lung diseases, contributing to disease progression. Biofilm growth and a propensity to evolve multidrug resistance phenotypes drastically limit the available therapeutic options. In this perspective, there has been growing interest in evaluating combination therapies, especially for drugs that can be administered by nebulization, which allows high drug concentrations to be reached at the site of infections while limiting systemic toxicity. Here, we investigated the potential antibiofilm activity of N-acetylcysteine (NAC) alone and in combination with colistin against a panel of P. aeruginosa strains (most of which are from CF patients) and the transcriptomic response of a P. aeruginosa CF strain to NAC exposure. NAC alone (8,000 mg/L) showed a limited and strain-dependent antibiofilm activity. Nonetheless, a relevant antibiofilm synergism of NAC-colistin combinations (NAC at 8,000 mg/L plus colistin at 2 to 32 mg/L) was observed with all strains. Synergism was also confirmed with the artificial sputum medium model. RNA sequencing of NAC-exposed planktonic cultures revealed that NAC (8,000 mg/L) mainly induced (i) a Zn2+ starvation response (known to induce attenuation of P. aeruginosa virulence), (ii) downregulation of genes of the denitrification apparatus, and (iii) downregulation of flagellar biosynthesis pathway. NAC-mediated inhibition of P. aeruginosa denitrification pathway and flagellum-mediated motility were confirmed experimentally. These findings suggested that NAC-colistin combinations might contribute to the management of biofilm-associated P. aeruginosa lung infections. NAC might also have a role in reducing P. aeruginosa virulence, which could be relevant in the very early stages of lung colonization. IMPORTANCE Pseudomonas aeruginosa biofilm-related chronic lung colonization contributes to cystic fibrosis (CF) disease progression. Colistin is often a last-resort antibiotic for the treatment of such P. aeruginosa infections, and it has been increasingly used in CF, especially by nebulization. N-acetylcysteine (NAC) is a mucolytic agent with antioxidant activity, commonly administered with antibiotics for the treatment of lower respiratory tract infections. Here, we show that NAC potentiated colistin activity against in vitro biofilms models of P. aeruginosa strains, with both drugs tested at the high concentrations achievable after nebulization. In addition, we report the first transcriptomic data on the P. aeruginosa response to NAC exposure.

PMID:35735984 | DOI:10.1128/spectrum.01006-22

Drug Des Devel Ther. 2022 Jun 16;16:1865-1883. doi: 10.2147/DDDT.S214174. eCollection 2022.

ABSTRACT

SMA (5q SMA) is an autosomal recessive neuromuscular disease with an estimated incidence of approximately 1 in 11,000 live births, characterized by progressive degeneration and loss of α-motor neurons in the spinal cord and brain stem, resulting in progressive muscle weakness. The disease spectrum is wide, from a serious congenital to a mild adult-onset disease. SMA is caused by biallelic mutations in the SMN1 gene and disease severity is modified primarily by SMN2 copy number. Before the advent of specific disease altering treatments, SMA was the second most common fatal autosomal recessive disorder after cystic fibrosis and the most common genetic cause of infant mortality. Nusinersen, risdiplam, and onasemnogene abeparvovec are presently the only approved disease modifying therapies for SMA, and the aim of this review is to discuss their mode of action, effects, safety concerns, and results from real-world experience. All exert their action by increasing the level of SMN protein in lower motor neuron. Nusinersen and risdiplam by modifying the SMN2 gene product, and onasemnogene abeparvovec by delivering SMN1 gene copies into cells. All have an established clinical efficacy. An important feature shared by all three is that early intervention is associated with a better treatment outcome, such that in cases where treatment is initiated in an early pre-symptomatic period, it may result in normal - or almost normal - motor development. Thus, early diagnosis followed by swift initiation of treatment is fundamental for the treatment response and consequently long-term prognosis in SMA type 1, and probably SMA type 2. The same principle similarly applies to the milder phenotypes. All three therapies are relatively novel, with risdiplam being the latest addition. Except for nusinersen, real-world data are still scarce, and long-term data are quite naturally lacking.

PMID:35734367 | PMC:PMC9208376 | DOI:10.2147/DDDT.S214174