Cystic fibrosis in the era of precision medicine

The predictive role of lung clearance index on FEV1 decline in cystic fibrosis

BACKGROUND

The lung clearance index (LCI) is a sensitive lung function index that is used to detect early lung disease changes in children with cystic fibrosis (CF). This study aimed to define the predictive role of baseline LCI, along with other potential factors on the change in forced expiratory volume in one second (FEV1) during one-year follow-up in CF patients who had a percent predicted (pp) FEV1≥80.

METHODS

LCI was concurrently performed on 57 CF patients who had ppFEV1 ≥80 at month zero. The ppFEV1 decline was evaluated prospectively during the one year follow up. The primary outcome of ppFEV1 decline in the study group in one year was dichotomized according to the median value for the decline in ppFEV1, which was 3.7. The LCI value predicting ppFEV1 decline at the end of one year was calculated with receiver operating characteristic curve analysis. Regression analysis was performed. Furthermore, a decision tree was constructed using classification and regression tree methods to better define the potential effect of confounders on the ppFEV1 decline.

RESULTS

The LCI value for predicting ppFEV1 decline >3.7% at the end of one year was 8.2 (area under the curve: 0.80) Multivariable regression analysis showed that the absence of the F508del mutation in at least one allele, LCI >8.2 and initial FEV1 z-score were predictors of a ppFEV1 decline >3.7 (p<0.001). Factors altering ppFEV1 decline>3.7% at the end of one-year evaluated by decision trees were as follows: initial FEV1 z-score, type of CFTR mutation, LCI value and initial weight-for-age z-score.

CONCLUSIONS

LCI is sensitive for predicting ppFEV1 decline in patients with ppFEV1 ≥80 along with the initial FEV1-z-score and type of CFTR mutation.

Optimization of ionizable lipids for aerosolizable mRNA lipid nanoparticles

Although mRNA lipid nanoparticles (LNPs) are highly effective as vaccines, their efficacy for pulmonary delivery has not yet fully been established. A major barrier to this therapeutic goal is their instability during aerosolization for local delivery. This imparts a shear force that degrades the mRNA cargo and therefore reduces cell transfection. In addition to remaining stable upon aerosolization, mRNA LNPs must also possess the aerodynamic properties to achieve deposition in clinically relevant areas of the lungs. We addressed these challenges by formulating mRNA LNPs with SM-102, the clinically approved ionizable lipid in the Spikevax COVID-19 vaccine. Our lead candidate, B-1, had the highest mRNA expression in both a physiologically relevant air-liquid interface (ALI) human lung cell model and in healthy mice lungs upon aerosolization. Further, B-1 showed selective transfection in vivo of lung epithelial cells compared to immune cells and endothelial cells. These results show that the formulation can target therapeutically relevant cells in pulmonary diseases such as cystic fibrosis. Morphological studies of B-1 revealed differences in the surface structure compared to LNPs with lower transfection efficiency. Importantly, the formulation maintained critical aerodynamic properties in simulated human airways upon next generation impaction. Finally, structure-function analysis of SM-102 revealed that small changes in the number of carbons can improve upon mRNA delivery in ALI human lung cells. Overall, our study expands the application of SM-102 and its analogs to aerosolized pulmonary delivery and identifies a potent lead candidate for future therapeutically active mRNA therapies.

Emerging biomedical imaging-based companion diagnostics for precision medicine

The tumor heterogeneity, which leads to individual variations in tumor microenvironments, causes poor prognoses and limits therapeutic response. Emerging technology such as companion diagnostics (CDx) detects biomarkers and monitors therapeutic responses, allowing identification of patients who would benefit most from treatment. However, currently, most US Food and Drug Administration-approved CDx tests are designed to detect biomarkers in vitro and ex vivo, making it difficult to dynamically report variations of targets in vivo. Various medical imaging techniques offer dynamic measurement of tumor heterogeneity and treatment response, complementing CDx tests. Imaging-based companion diagnostics allow for patient stratification for targeted medicines and identification of patient populations benefiting from alternative therapeutic methods. This review summarizes recent developments in molecular imaging for predicting and assessing responses to cancer therapies, as well as the various biomarkers used in imaging-based CDx tests. We hope this review provides informative insights into imaging-based companion diagnostics and advances precision medicine.

Understanding motivation for Australian adolescents and young adults with cystic fibrosis: Modifiable factors to support self-management

Cystic fibrosis (CF) is Australia's most common life limiting genetic condition, characterised by declining health and quality of life (QoL) over time. Despite improvements in treatment, there remains no cure. Adolescents and young adults (AYAs) with CF experience broad impacts to psychosocial functioning and QoL, as well as major transitions in care, all at a time of significant developmental change. The importance of developmentally tailored approaches to youth health care and self-management for young people with CF are well understood. However, to date, models of youth specific self-management have been lacking and motivation for young people with CF has not been well explored. This qualitative study, based on a social constructionist epistemological framework, addresses this gap. A total of 21 AYAs aged 15-30 years were recruited through one paediatric and one adult Australian CF centre. Demographic, clinical and distress data were captured to describe health complexity. Semi-structured interviews were audio-recorded, transcribed and analysed using thematic analysis. Participants were representative of Australian AYAs with CF by demography and clinical status. Alarmingly, over a third reported clinically significant distress. Two themes emerged. The first Identified impacts to motivation and self-management resulting from the challenges of managing CF, life and care. These included time and competing priorities, changing health statis, mental health, social factors, unmet needs and health system complexity. The second identified factors that support motivation including: achievement, meaning and purpose; consequence avoidance; and accountability. These results illustrate the importance of AYA specific, theoretically founded, holistic self-management models which extend beyond current theoretical approaches that aim to understand behaviour change or address barriers, in isolation from motivation. Improved approaches to care based on these findings are essential to foster positive behavioural change, support self-management and foster the best health outcomes for young people living with CF.

Soft, skin-interfaced sweat stickers for cystic fibrosis diagnosis and management

The concentration of chloride in sweat remains the most robust biomarker for confirmatory diagnosis of cystic fibrosis (CF), a common life-shortening genetic disorder. Early diagnosis via quantitative assessment of sweat chloride allows prompt initiation of care and is critically important to extend life expectancy and improve quality of life. The collection and analysis of sweat using conventional wrist-strapped devices and iontophoresis can be cumbersome, particularly for infants with fragile skin, who often have insufficient sweat production. Here, we introduce a soft, epidermal microfluidic device ("sweat sticker") designed for the simple and rapid collection and analysis of sweat. Intimate, conformal coupling with the skin supports nearly perfect efficiency in sweat collection without leakage. Real-time image analysis of chloride reagents allows for quantitative assessment of chloride concentrations using a smartphone camera, without requiring extraction of sweat or external analysis. Clinical validation studies involving patients with CF and healthy subjects, across a spectrum of age groups, support clinical equivalence compared to existing device platforms in terms of accuracy and demonstrate meaningful reductions in rates of leakage. The wearable microfluidic technologies and smartphone-based analytics reported here establish the foundation for diagnosis of CF outside of clinical settings.

Telephone surveillance during 2019 novel coronavirus disease: Is it a helpful diagnostic tool for detecting acute pulmonary exacerbations in children with chronic lung disease?

INTRODUCTION

The global burden of the 2019 novel coronavirus disease pandemic on the healthcare system, as well as the high transmission risk of coronavirus disease has led to the use of alternative strategies for evaluation of children with chronic conditions. In this context, telemedicine has become the effective and affordable choice. In this study we aimed to evaluate the efficiency of telephone visits to determine pulmonary exacerbations and hospitalization rates of children with cystic fibrosis and interstitial lung disease.

METHODS

A total of 119 children with cystic fibrosis or interstitial lung disease were enrolled and provided cases in which telephone visits were applied during the peak time of the coronavirus disease pandemic in our country. The recordings of respiratory, gastrointestinal and other symptoms, nutrition status, rate of acute pulmonary exacerbation, treatments initiated by telephone visits, referral to hospital and hospitalization were established from the electronic health reports of the patients.

RESULTS

Thirteen patients (10.9%) were symptomatic, 12 of them (10%) were diagnosed with acute pulmonary exacerbation. One patient was diagnosed with peripheral facial paralysis. Nine patients were recalled to the hospital and seven patients (5.8%) were hospitalised.

DISCUSSION

Using telemedicine the health status of patients can be defined, and patients can be guided on proper healthcare that they need, especially during the times of pandemics which we are facing. Communication with patients while minimising the risk of exposure to coronavirus disease is an important advantage of telemedicine. Telemedicine will have to be implemented on our daily medical practice in the near future.

Rescue of common exon-skipping mutations in cystic fibrosis with modified U1 snRNAs

In cystic fibrosis (CF), the correction of splicing defects represents an interesting therapeutic approach to restore normal CFTR function. In this study, we focused on 10 common mutations/variants 711+3A>G/C, 711+5G>A, TG13T3, TG13T5, TG12T5, 1863C>T, 1898+3A>G, 2789+5G>A, and 3120G>A that induce skipping of the corresponding CFTR exons 5, 10, 13, 16, and 18. To rescue the splicing defects we tested, in a minigene assay, a panel of modified U1 small nuclear RNAs (snRNAs), named Exon Specific U1s (ExSpeU1s), that was engineered to bind to intronic sequences downstream of each defective exon. Using this approach, we show that all 10 splicing mutations analyzed are efficiently corrected by specific ExSpeU1s. Using complementary DNA-splicing competent minigenes, we also show that the ExspeU1-mediated splicing correction at the RNA level recovered the full-length CFTR protein for 1863C>T, 1898+3A>G, 2789+5G>A variants. In addition, detailed mutagenesis experiments performed on exon 13 led us to identify a novel intronic regulatory element involved in the ExSpeU1-mediated splicing rescue. These results provide a common strategy based on modified U1 snRNAs to correct exon skipping in a group of disease-causing CFTR mutations.

Pharmacogenomics of Antidepressant and Antipsychotic Treatment: How Far Have We Got and Where Are We Going?

In recent decades, very few new psychiatric drugs have entered the market. Thus, improvement in the use of antidepressant and antipsychotic therapy has to focus mainly on enhanced and more personalized treatment with the currently available drugs. One important aspect of such individualization is emphasizing interindividual differences in genes relevant to treatment, an area that can be termed neuropsychopharmacogenomics. Here, we review previous efforts to identify such critical genetic variants and summarize the results obtained to date. We conclude that most clinically relevant genetic variation is connected to phase I drug metabolism, in particular to genetic polymorphism of CYP2C19 and CYP2D6. To further improve individualized pharmacotherapy, there is a need to take both common and rare relevant mutations into consideration; we discuss the present and future possibilities of using whole genome sequencing to identify patient-specific genetic variation relevant to treatment in psychiatry. Translation of pharmacogenomic knowledge into clinical practice can be considered for specific drugs, but this requires education of clinicians, instructive guidelines, as well as full attention to polypharmacy and other clinically relevant factors. Recent large patient studies (n > 1,000) have replicated previous findings and produced robust evidence warranting the clinical utility of relevant genetic biomarkers. To further judge the clinical and financial benefits of preemptive genotyping in psychiatry, large prospective randomized trials are needed to quantify the value of genetic-based patient stratification in neuropsychopharmacotherapy and to demonstrate the cost-effectiveness of such interventions.

Nanomedicine Approaches for the Pulmonary Treatment of Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disease affecting today nearly 70,000 patients worldwide and characterized by a hypersecretion of thick mucus difficult to clear arising from the defective CFTR protein. The over-production of the mucus secreted in the lungs, along with its altered composition and consistency, results in airway obstruction that makes the lungs susceptible to recurrent and persistent bacterial infections and endobronchial chronic inflammation, which are considered the primary cause of bronchiectasis, respiratory failure, and consequent death of patients. Despite the difficulty of treating the continuous infections caused by pathogens in CF patients, various strategies focused on the symptomatic therapy have been developed during the last few decades, showing significant positive impact on prognosis. Moreover, nowadays, the discovery of CFTR modulators as well as the development of gene therapy have provided new opportunity to treat CF. However, the lack of effective methods for delivery and especially targeted delivery of therapeutics specifically to lung tissues and cells limits the efficiency of the treatments. Nanomedicine represents an extraordinary opportunity for the improvement of current therapies and for the development of innovative treatment options for CF previously considered hard or impossible to treat. Due to the peculiar environment in which the therapies have to operate characterized by several biological barriers (pulmonary tract, mucus, epithelia, bacterial biofilm) the use of nanotechnologies to improve and enhance drug delivery or gene therapies is an extremely promising way to be pursued. The aim of this review is to revise the currently used treatments and to outline the most recent progresses about the use of nanotechnology for the management of CF.

Cystic Fibrosis: Advancing Along the Continuum

Cystic fibrosis (CF) is an autosomal recessive genetic disorder resulting from a mutation in the gene which encodes a cellular transmembrane protein channel known as the CF transmembrane conductance regulator. Located systemically on the surface of numerous cells, these altered channels yield multisystem dysfunction. Typical manifestations seen are chronic, progressive, obstructive lung disease, pancreatic insufficiency, CF-related diabetes mellitus, malabsorption and malnutrition, liver disease, and infertility.Once considered a pediatric disorder, through developments in innovative care and therapeutic modalities, CF now spans the life continuum and has established itself as an ageless disease. Facing management of maturing-life issues, advanced practice nurses (APNs) in pediatrics now find themselves needing to collaborate with or facilitate transition of care to other APNs, such as nurse midwives and adult APNs, as well as their counterpart specialists in medicine, all while maintaining open communication with the patient, family and managing CF center.

Applications of lung clearance index in monitoring children with cystic fibrosis

A sensitive, reproducible and feasible measure of lung function for monitoring the respiratory health is a prerequisite for the optimization of management of the patients with cystic fibrosis (CF). Spirometry has been considered the method of choice, although it is applicable only in children older than 6 years of age, as good cooperation is necessary for its proper performance. However, over the last 15 years, scientific interest in gas dilution techniques and particularly in multiple breath wash out (MBW) method has been revived. The most commonly reported index of MBW is lung clearance index (LCI). The aim of this review is to present the most recent developments in the application of LCI as a monitoring index of respiratory status of CF patients. LCI is a sensitive and reproducible marker of ventilation inhomogeneity. It is more sensitive than spirometry and, unlike spirometry; it can be performed across the whole pediatric age range. Since it is dependent on body size, until at least the age of 6 years, the relative and not the absolute changes are more appropriate for providing clinically meaningful conclusion on ventilation inhomogeneity. Until now, MBW has been mainly used as a research tool. Based on the currently available data LCI cannot safely predict high-resolution computed tomography findings in children with CF, especially in infants. It can be used as an end-point measure for the assessment of beneficial effect of interventions. However, its utility as an outcome measure for the efficacy of therapeutic interventions seems to be dependent on the pathophysiologic mechanisms that underlie each intervention. It seems that more studies, especially longitudinal ones, are required in order to fully clarify the clinical usefulness of LCI, not only in the research setting, but also in every day practice of CF clinic.

Adapting Proteostasis and Autophagy for Controlling the Pathogenesis of Cystic Fibrosis Lung Disease

Cystic fibrosis (CF), a fatal genetic disorder predominant in the Caucasian population, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (Cftr) gene. The most common mutation is the deletion of phenylalanine from the position-508 (F508del-CFTR), resulting in a misfolded-CFTR protein, which is unable to fold, traffic and retain its plasma membrane (PM) localization. The resulting CFTR dysfunction, dysregulates variety of key cellular mechanisms such as chloride ion transport, airway surface liquid (ASL) homeostasis, mucociliary-clearance, inflammatory-oxidative signaling, and proteostasis that includes ubiquitin-proteasome system (UPS) and autophagy. A collective dysregulation of these key homoeostatic mechanisms contributes to the development of chronic obstructive cystic fibrosis lung disease, instead of the classical belief focused exclusively on ion-transport defect. Hence, therapeutic intervention(s) aimed at rescuing chronic CF lung disease needs to correct underlying defect that mediates homeostatic dysfunctions and not just chloride ion transport. Since targeting all the myriad defects individually could be quite challenging, it will be prudent to identify a process which controls almost all disease-promoting processes in the CF airways including underlying CFTR dysfunction. There is emerging experimental and clinical evidence that supports the notion that impaired cellular proteostasis and autophagy plays a central role in regulating pathogenesis of chronic CF lung disease. Thus, correcting the underlying proteostasis and autophagy defect in controlling CF pulmonary disease, primarily via correcting the protein processing defect of F508del-CFTR protein has emerged as a novel intervention strategy. Hence, we discuss here both the rationale and significant therapeutic utility of emerging proteostasis and autophagy modulating drugs/compounds in controlling chronic CF lung disease, where targeted delivery is a critical factor-influencing efficacy.

Precision Medicine In Action: The Impact Of Ivacaftor On Cystic Fibrosis-Related Hospitalizations

Cystic fibrosis is a life-threatening genetic disease that causes severe damage to the lungs. Ivacaftor, the first drug that targeted the underlying defect of the disease caused by specific mutations, is a sterling example of the potential of precision medicine. Clinical trial and registry studies showed that ivacaftor improved outcomes and reduced hospitalizations. Our study used US administrative claims data to assess the real-world effectiveness of ivacaftor. Comparing twelve-month rates before and after starting the use of ivacaftor among people who initiated therapy during 2012-2015, we found that overall and cystic fibrosis-related inpatient admissions fell by 55 percent and 81 percent, respectively. There was a comparable reduction in inpatient spending. Ivacaftor appears to be effective for multiple mutations that cause the disease, as suggested by the fact that during the study period, ivacaftor's use was extended to nine additional mutations in 2014. Examination of evidence from clinical trial, clinical care, and administrative data sources is important for understanding the real-world effectiveness of precision medicines such as ivacaftor.

Asthma: Differential Diagnosis and Comorbidities

Childhood asthma remains a multifactorial disease with heterogeneous clinical phenotype and complex genetic inheritance. The primary aim of asthma management is to achieve control of symptoms, in order to reduce the risk of future exacerbations and progressive loss of lung function, which results especially challenging in patients with difficult asthma. When asthma does not respond to maintenance treatment, firstly, the correct diagnosis needs to be confirmed and other diagnosis, such as cystic fibrosis, primary ciliary dyskinesia, immunodeficiency conditions or airway and vascular malformations need to be excluded. If control remains poor after diagnostic confirmation, detailed assessments of the reasons for asthma being difficult-to-control are needed. Moreover, all possible risk factors or comorbidities (gastroesophageal reflux, rhinosinusitis, dysfunctional breathing and/or vocal cord dysfunction, obstructive sleep apnea and obesity) should be investigated. At the same time, the possible reasons for poor symptom control need to be find in all modifiable factors which need to be carefully assessed. Non-adherence to medication or inadequate inhalation technique, persistent environmental exposures and psychosocial factors are, currently, recognized as the more common modifiable factors. Based on these premises, investigation and management of asthma require specialist multidisciplinary expertise and a systematic approach to characterizing patients' asthma phenotypes and delivering individualized care. Moreover, since early wheezers are at higher risk of developing asthma, we speculate that precocious interventions aimed at early diagnosis and prevention of modifiable factors might affect the age at onset of wheezing, reduce the prevalence of persistent later asthma and determine long term benefits for lung health.

Molecular principles for heparin oligosaccharide-based inhibition of neutrophil elastase in cystic fibrosis

Cystic fibrosis (CF) is a multifactorial disease in which dysfunction of protease-antiprotease balance plays a key role. The current CF therapy relies on dornase α, hypertonic saline, and antibiotics and does not address the high neutrophil elastase (NE) activity observed in the lung and sputum of CF patients. Our hypothesis is that variants of heparin, which potently inhibit NE but are not anticoagulant, would help restore the protease-antiprotease balance in CF. To realize this concept, we studied molecular principles governing the effectiveness of different heparins, especially 2-O,3-O-desulfated heparin (ODSH), in the presence of sputum components and therapeutic agents. Using sputa from CF patients and an NE activity assay, we found that heparins are ineffective if used in the absence of dornase. This is true even when mucolytics, such as DTT or N-acetylcysteine, were used. Computational modeling suggested that ODSH and DNA compete for binding to an overlapping allosteric site on NE, which reduces the anti-NE potential of ODSH. NE inhibition of both DNA and ODSH is chain length-dependent, but ODSH chains exhibit higher potency per unit residue length. Likewise, ODSH chains exhibit higher NE inhibition potential compared with DNA chains in the presence of saline. These studies suggest fundamental differences in DNA and ODSH recognition and inhibition of NE despite engaging overlapping sites and offer unique insights into molecular principles that could be used in developing antiprotease agents in the presence of current treatments, such as dornase and hypertonic saline.

A Peptide Nucleic Acid against MicroRNA miR-145-5p Enhances the Expression of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) in Calu-3 Cells

Peptide nucleic acids (PNAs) are very useful tools for gene regulation at different levels, but in particular in the last years their use for targeting microRNA (anti-miR PNAs) has provided impressive advancements. In this respect, microRNAs related to the repression of cystic fibrosis transmembrane conductance regulator (CFTR) gene, which is defective in cystic fibrosis, are of great importance in the development of new type of treatments. In this paper we propose the use of an anti-miR PNA for targeting miR-145, a microRNA reported to suppress CFTR expression. Octaarginine-anti-miR PNA conjugates were delivered to Calu-3 cells, exerting sequence dependent targeting of miR-145-5p. This allowed to enhance expression of the miR-145 regulated CFTR gene, analyzed at mRNA (RT-qPCR, Reverse Transcription quantitative Polymerase Chain Reaction) and CFTR protein (Western blotting) level.

[Rare metabolic disorders and urolithiasis]

Numerous metabolic anomalies, which often have no direct pathological relevance when considered individually, are found in all people. In most patients with urinary tract stones, it can be assumed that a specific combination or interaction of these anomalies occurs, thus, resulting in stone formation, but only after individual exogenous risk factors are triggered. Lithogenesis is the result of a cascade of different "events" that are temporally close to one another, but sometimes these events interact strong enough that significant stone growth occurs. Chronic metabolic disorders usually lead to permanently altered urine compositions. The occurrence of physiological urine constituents in nonnormal concentration ratios and/or the nonphysiological excretion of metabolic products can significantly increase the lithogenicity of urine, so that urolithiasis can manifest itself as a clinical symptom. In cases of urolithiasis of unknown origin, a potentially hidden rare metabolic anomaly should always be considered. In addition, if a patient has a known metabolic disease, then this should always be taken into account as a risk factor for stone formation and attempts should be taken to clarify its influence on urine composition. This also applies to the efficacy of a therapy. A distinct link between a metabolic disease and stone formation is generally rare and will likely remain so despite significant advances regarding differential diagnosis and etiopathology. This article focuses on very rare metabolic causes and/or genetic syndromes which may be associated with urolithiasis. Patients receiving symptomatic stone treatment should receive life-long follow-up care from a urologist because reducing the recurrence rate helps to improve the quality of life of the patients.