Cystic Fibrosis-Related Diabetes

Pancreatic exocrine damage induces beta cell stress in zebrafish larvae

AIMS/HYPOTHESIS

Excessive endoplasmic reticulum (ER) stress in beta cells can impair proliferation and contribute to autoimmune responses such as the destruction of beta cells in type 1 diabetes. Exocrine-beta cell interactions affect beta cell growth and function. Notably, exocrine abnormalities are frequently observed alongside overloaded beta cells in different types of diabetes, suggesting that exocrine stress may induce beta cell ER stress and loss. While a cause-consequence relationship between exocrine stress and beta cell function cannot be addressed in humans, it can be studied in a zebrafish model. Larvae develop a pancreas with a human-like morphology by 120 h post-fertilisation, providing a valuable dynamic model for studying pancreatic interactions. Our aim was to target exocrine cells specifically and address beta cell status using transgenic zebrafish models and reporters.

METHODS

To explore the impact of exocrine damage on beta cell fitness, we generated a novel zebrafish model allowing exocrine pancreas ablation, using a nifurpirinol-nitroreductase system. We subsequently assessed the in vivo effects on beta cells by live-monitoring dynamic cellular events, such as ER stress, apoptosis and changes in beta cell number and volume.

RESULTS

Exocrine damage in zebrafish decreased pancreas volume by approximately 50% and changed its morphology. The resulting exocrine damage induced ER stress in 60-90% of beta cells and resulted in a ~50% reduction in their number.

CONCLUSIONS/INTERPRETATION

The zebrafish model provides a robust platform for investigating the interplay between exocrine cells and beta cells, thereby enhancing further insights into the mechanisms driving pancreatic diseases such as type 1 diabetes.

Elevated glucose increases methicillin-resistant Staphylococcus aureus antibiotic tolerance in a cystic fibrosis airway epithelial cell infection model

Background

In a healthy lung, the airway epithelium regulates glucose transport to maintain low glucose concentrations in the airway surface liquid (ASL). However, hyperglycemia and chronic lung diseases, such as cystic fibrosis (CF), can result in increased glucose in bronchial aspirates. People with CF are also at increased risk of lung infections caused by bacterial pathogens, including methicillin-resistant Staphylococcus aureus. Yet, it is not known how increased airway glucose availability affects bacteria in chronic CF lung infections or impacts treatment outcomes.

Methods

To model the CF airways, we cultured immortalized CF (CFBE41o-) and non-CF (16HBE) human bronchial epithelial cells at air liquid interface (ALI). Glucose concentrations in the basolateral media were maintained at 5.5 mM or 12.5 mM, to mimic a normal and hyperglycemic milieu respectively. 2-deoxyglucose was added to high glucose culture media to restrict glucose availability. We collected ASL, basolateral media, and RNA from ALI cultures to assess the effects of elevated glucose. We also inoculated S. aureus onto the apical surface of normal or high glucose ALI cultures and observed the results of antibiotic treatment post-inoculation. S. aureus growth was measured by enumerating viable colony forming units (CFU) and with fluorescence microscopy. The effects of elevated glucose on in vitro growth and antibiotic treatment were also evaluated in standard bacterial culture medium and synthetic CF medium (SCFM).

Results

We found that glucose concentrations in the ASL of ALI cultures maintained in normal or high glucose mimicked levels measured in breath condensate assays from people with CF and hyperglycemia. Additionally, we found hyperglycemia increased S. aureus aggregation and antibiotic resistance during infection of cells maintained in high glucose compared to normal glucose conditions. Heightened antibiotic tolerance or resistance as not observed during in vitro growth with elevated glucose. Limiting glucose with 2-deoxyglucose both decreased aggregation and reduced antibiotic resistance back to levels comparable to non-hyperglycemic conditions.

Conclusions

These data indicate hyperglycemia alters S. aureus growth during infection and may reduce efficacy of antibiotic treatment. Glucose restriction is a potential option that could be explored to limit bacterial growth and improve treatment outcomes in chronic airway infections.

Changes in immunofluorescence staining during islet regeneration in a cystic fibrosis-related diabetes (CFRD) ferret model

BACKGROUND

Knockout (KO) ferrets with the cystic fibrosis transmembrane conductance regulator (CFTR) exhibit distinct phases of dysglycemia and pancreatic remodeling prior to cystic fibrosis-related diabetes (CFRD) development. Following normoglycemia during the first month of life (Phase l), hyperglycemia occurs during the subsequent 2 months (Phase Il) with decreased islet mass, followed by a period of near normoglycemia (Phase Ill) in which the islets regenerate. We aimed to characterize islet hormone expression patterns across these Phases.

METHODS

Immunofluorescence staining per islet area was performed to characterize islet hormone expression patterns in age matched CFTR KO and wild type (WT) ferrets, focusing on the first three phases.

RESULTS

In Phase I, insulin staining intensity was higher in CF (p < 0.01) than WT but decreased in Phase III (p < 0.0001). Glucagon was lower in CF during Phases I and increased in Phase III, while proinsulin decreased (p < 0.0001) Phases II and III. CF sections showed lower proinsulin-to-insulin ratio in Phase I (p < 0.01) and in Phase III (p < 0.05) compared to WT. Conversely, glucagon-to-insulin ratio was lower in CF in Phase I (p < 0.0001) but increased in Phase III (p < 0.0001). Mender's coefficient overlap showed higher overlap of insulin over proinsulin in CF sections in Phase II (p < 0.001) and Phase III (p < 0.0001) compared to WT. Mender's coefficient rate was higher in CF sections during Phase II (p < 0.001).

CONCLUSION

CF ferret islets revealed significant immunofluorescent staining changes compared to WT during various phases of disease, providing insights into CRFD pathophysiology.

Low-Dose Ketone Monoester Administration in Adults with Cystic Fibrosis: A Pilot and Feasibility Study

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have greatly improved outcomes in persons with CF (pwCF); however, there is still significant heterogeneity in clinical responses, particularly with regard to respiratory infection and inflammation. Exogenous administration of ketones has profound systemic anti-inflammatory effects and produces several nutrient-signaling and metabolic effects that may benefit multiple organ systems affected in pwCF. This pilot study was designed to determine the feasibility of administration of a ketone monoester (KME) to increase circulating D-beta hydroxybutyrate concentrations (D-βHB) and to improve subjective measures of CF-specific quality of life and markers of inflammation in serum and sputum in adults with CF.

METHODS

Fourteen participants receiving modulator therapy were randomized to receive either KME (n = 9) or placebo control (PC, n = 5) for 5-7 days during hospitalization for treatment of acute pulmonary exacerbation or as outpatients under standard care.

RESULTS

The KME was well tolerated, with only mild reports of gastrointestinal distress. D-βHB concentrations increased from 0.2 ± 0.1 mM to 1.6 ± 0.6 mM in the KME group compared to 0.2 ± 0.0 to 0.3 ± 0.1 in the PC group (p = 0.011) within 15 min following consumption and remained elevated, relative to baseline, for over 2 h. Pulmonary function was not altered after single- or short-term KME administration, but participants in the KME group self-reported higher subjective respiratory scores compared to PC in both cases (p = 0.031). Plasma inflammatory markers were not statistically different between groups following the short-term (5-7 d) intervention (p > 0.05). However, an exploratory analysis of plasma pre- and post-IL-6 concentrations was significant (p = 0.028) in the KME group but not PC. Sputum IFNγ (p = 0.057), IL-12p70 (p = 0.057), IL-1β (p = 0.100), IL-15 (p = 0.057), IL-1α (p = 0.114), and MPO (p = 0.133) were lower in the KME group compared to PC but did not achieve statistical significance.

CONCLUSIONS

With the emerging role of exogenous ketones as nutrient signaling molecules and mediators of metabolism, we showed that KME is well tolerated, increases circulating D-βHB concentrations, and produces outcomes that justify the need for large-scale clinical trials to investigate the role of KME on whole-body and tissue lipid accumulation and inflammation in pwCF.

Advances in diabetes technology to improve the lives of people with cystic fibrosis

People with cystic fibrosis (CF) are at risk for dysglycaemia caused by progressive beta cell dysfunction and destruction due to pancreatic exocrine disease and fibrosis. CF-related diabetes (CFRD) is a unique form of diabetes that has distinctive features from both type 1 and type 2 diabetes. Recent advances in diabetes technology may be of particular benefit in this population given the complex, multi-system organ involvement and challenging health issues that people with CFRD often face. This review summarises how diabetes technologies, such as continuous glucose monitors (CGMs) and insulin delivery devices: (1) have improved our understanding of CFRD, including how hyperglycaemia affects clinical outcomes in people with CF; (2) may be helpful in the screening and diagnosis of CFRD; and (3) offer promise for improving the management of CFRD and easing the burden that this diagnosis can add to an already medically complicated patient population.

Codevelopment of a model of care for adults living with cystic fibrosis-related diabetes

BACKGROUND

Cystic fibrosis (CF) related diabetes affects up to half of all adults with CF and is associated with higher morbidity and mortality. Our aim is to codevelop an ideal model of care that integrates diabetes technology and better meets the needs of adults living with the condition to improve attendance, engagement, service satisfaction, and clinical outcomes.

METHODS

Using qualitative research methods, we evaluated disease perceptions, barriers, and enablers to optimal CF-related diabetes management and service delivery. Integration of continuous glucose monitoring (CGM) was also explored. An initial broad purposive consumer survey was followed by focus groups with end-users. Grounded theory approach was utilized with major problem areas identified then explored, coded, and grouped into requisites for an "ideal model of care" for adults living with CF-related diabetes.

RESULTS

Two key themes emerged (i) an ideal model of care consisted of a dual-specialty service co-led by endocrinology and CF physicians and supported by diabetes educator and CF dietitian with a goal to provide consistent and personalized diabetes management and (ii) CGM was acceptable for use in adults with CF-related diabetes with many perceived benefits and should be integrated into the model of care. Barriers to optimizing glycemic control included diet, finger-prick testing, reduced access to CGM, and pulmonary exacerbations. End-user feedback on CGM was overwhelmingly positive with regard to operability. CGM was also identified as a tool that could be used to engage, educate, and empower adults living with CF-related diabetes and facilitate constructive and personalized clinical decision-making by healthcare providers.

CONCLUSION

For adults living with CF, a diagnosis of diabetes is associated with increased treatment burden. Our findings suggest an "ideal model of care" for CF-related diabetes would be co-led by endocrinology services integrated within a pre-existing CF service, incorporating CGM.

Evaluation of Oral Glucose Tolerance Test Results in Children with Cystic Fibrosis

Objectives

Current guidelines suggest that patients with cystic fibrosis (CF), who are over the age of 10, should be annually evaluated with oral glucose tolerance test (OGTT). In this study, it was aimed to evaluate the OGTT results in patients above the age of 10, who were followed up in our center with the diagnosis of CF.

Methods

In the study, 46 patients with CF at the age of 10 and above, who underwent OGTT were included. Data such as gender, age at diagnosis, anthropometric measurements, lung function (FEV1 %) and the OGTT results were obtained. In the analysis, the patient groups with normal glucose tolerance (NGT) and abnormal glucose tolerance(AGT) were compared.

Results

NGT was found in 37(80.4%) of the patients, and AGT was found in 9(19.5%) of the patients. The median fasting glucose levels of the patients in the NGT group and the mean glucose levels measured at 120 minutes in the OGTT were found to be lower compared to the patients in the AGT group(p<0.005). Although the mean body weight, height, VKİ-SDS, FEV1in the AGT group were found to be lower than the patients in the NGT group, the difference was not statistically significant (p>0.05).

Conclusion

We detected AGT in approximately 1 out of 5 patients with CF who were at the age of 10 and above. Almost half (44.4%) of the patients with AGT were found to have normal fasting blood glucose levels. Therefore, cystic fibrosis-related diabetes screening should be performed with OGTT instead of fasting blood glucose in patients with CF.

Glycemic Variability and the Thickness of Retinal Layers in Cystic Fibrosis Patients with and without Cystic Fibrosis Related Diabetes

PURPOSE

Patients with cystic fibrosis (CF) are at risk to develop CF related diabetes (CFRD) and subsequently even diabetic neuro- and/or vasculopathy. We sought to determine if there are typical signs of diabetes-related retinal alterations present in CF patients with preserved and impaired glycemic control.

METHODS

During routine annual examination CF patients were offered an additional 7-day period of real time continuous glucose monitoring (rtCGM) and an ophthalmological examination including retinal optical coherence tomography (OCT). Patients were categorized according to the glycemic control, i.e. the results of an oral glucose tolerance test (OGTT) and rtCGM were taken into consideration. OCT data was analyzed by our previously published visual analysis software generating dedicated and spatially resolved deviation maps for visualization and quantification of differences in total retinal thickness and thickness of retinal nerve fiber layer (RNFL) as well as ganglion cell layer (GCL) in comparison to age-matched healthy controls and patients with either type 1 or type 2 diabetes mellitus.

RESULTS

Results of the rtCGM and/or OGTT enabled discrimination between patients with normal glycemic control (CFNG; n = 6), with abnormal glycemic control (CFAG; n = 6) and overt CFRD (n = 4). OCT data indicates gradually increasing retinal thinning in all 3 groups, depending on the degree of glucose metabolism disorder compared to healthy controls. At the foveal region total retinal thickness and GCL thickness were significantly thinner in CFRD patients compared to CFNG patients (total retinal thickness: 260.4 µm (239.3-270.8) vs. 275.4 µm (254.3-289.5); GCL: 11.82 µm (11.16-15.25) vs. 17.30 µm (13.95-19.82); each p < 0.05).

CONCLUSION

Although we investigated a rather small number of patients, we obtained evidence that intraretinal neurodegenerative changes occur in each of our subgroups (CFNG, CFAG, CFRD). Beyond this, our results favor the detrimental role of additional diabetes, as the deviations from healthy controls were most pronounced in the CFRD group and are similar to those seen in patients suffering from type 1 or type 2 diabetes.

Clinical and anthropometric evolution of individuals with cystic fibrosis during COVID-19 pandemic: A 24-month cohort study

OBJECTIVES

To analyze the evolution of clinical and anthropometric characteristics of children and adolescents with cystic fibrosis (CF) over 24 months, including the period of the COVID-19 pandemic.

METHODS

A longitudinal study with data collection from May 2018 to November 2020 in physical and electronic records from a pediatric reference center, including individuals with CF aged up to 18 years.

RESULTS

The sample encompassed 72 individuals. Weight (p < 0.01), height (p < 0.01), and body mass index (BMI) (p = 0.043) were higher in 2020 than in 2018. There were no significant changes in BMI-Z (p = 0.977) and in percentiles of weight (p = 0.540), height (p = 0.458), and BMI percentile (p = 0.454) between both periods. Pancreatic insufficiency was observed in 91.7% of patients in 2020, and there were twice as many confirmed cases of diabetes compared to 2018. There was a 9.7% increase in individuals colonized by the oxacillin-sensitive Staphylococcus aureus (OSSA) (p = 0.039) and an 11.1% reduction in non-colonized individuals (p = 0.008).

CONCLUSION

Although there was an increase in weight, height, and BMI from 2018 to 2020, there were no significant changes in BMI-Z and in percentiles of weight, height, and BMI percentile, suggesting that the anthropometric aspects of nutritional status did not change in this period of 2 years. Moreover, there was an increase in the prevalence of individuals colonized by OSSA and a reduction in the prevalence of individuals non-colonized with any bacteria.

Functional Consequences of CFTR Interactions in Cystic Fibrosis

Cystic fibrosis (CF) is a fatal autosomal recessive disorder caused by the loss of function mutations within a single gene for the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). CFTR is a chloride channel that regulates ion and fluid transport across various epithelia. The discovery of CFTR as the CF gene and its cloning in 1989, coupled with extensive research that went into the understanding of the underlying biological mechanisms of CF, have led to the development of revolutionary therapies in CF that we see today. The highly effective modulator therapies have increased the survival rates of CF patients and shifted the epidemiological landscape and disease prognosis. However, the differential effect of modulators among CF patients and the presence of non-responders and ineligible patients underscore the need to develop specialized and customized therapies for a significant number of patients. Recent advances in the understanding of the CFTR structure, its expression, and defined cellular compositions will aid in developing more precise therapies. As the lifespan of CF patients continues to increase, it is becoming critical to clinically address the extra-pulmonary manifestations of CF disease to improve the quality of life of the patients. In-depth analysis of the molecular signature of different CF organs at the transcriptional and post-transcriptional levels is rapidly advancing and will help address the etiological causes and variability of CF among patients and develop precision medicine in CF. In this review, we will provide an overview of CF disease, leading to the discovery and characterization of CFTR and the development of CFTR modulators. The later sections of the review will delve into the key findings derived from single-molecule and single-cell-level analyses of CFTR, followed by an exploration of disease-relevant protein complexes of CFTR that may ultimately define the etiological course of CF disease.

Vitamin D for glycemic control following an acute pulmonary exacerbation: A secondary analysis of a multicenter, double-blind, randomized, placebo-controlled trial in adults with cystic fibrosis

Individuals with cystic fibrosis (CF) often incur damage to pancreatic tissue due to a dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) protein, leading to altered chloride transport on epithelial surfaces and subsequent development of cystic fibrosis-related diabetes (CFRD). Vitamin D deficiency has been associated with the development of CFRD. This was a secondary analysis of a multicenter, double-blind, randomized, placebo-controlled study in adults with CF hospitalized for an acute pulmonary exacerbation (APE), known as the Vitamin D for the Immune System in Cystic Fibrosis (DISC) trial (NCT01426256). This was a pre-planned secondary analysis to examine if a high-dose bolus of cholecalciferol (vitamin D3) can mitigate declined glucose tolerance commonly associated with an acute pulmonary exacerbation (APE). Glycemic control was assessed by hemoglobin A1c (HbA1c) and fasting blood glucose levels before and 12 months after the study intervention. Within 72 hours of hospital admission, participants were randomly assigned to a single dose of oral vitamin D3 (250,000 IU) or placebo, and subsequently, received 50,000 IU of vitamin D3 or placebo every other week, beginning at month 3 and ending on month 12. Forty-nine of the 91 participants in the parent study were eligible for the secondary analysis. There were no differences in 12-month changes in HbA1c or fasting blood glucose in participants randomized to vitamin D or placebo. A high-dose bolus of vitamin D3 followed by maintenance vitamin D3 supplementation did not improve glycemic control in patients with CF after an APE.

Diagnosis, Management, and Prognosis of Cystic Fibrosis-Related Liver Disease in Children

Cystic fibrosis (CF) is a multifaceted disorder predominantly investigated for its pulmonary manifestations, yet patients with CF also exhibit a spectrum of extrapulmonary manifestations, notably those involving the hepatobiliary system. The latter constitutes the third leading cause of morbidity and mortality in individuals with CF. Cystic fibrosis-related liver disease (CFLD), with an escalating prevalence, manifests diverse clinical presentations ranging from hepatomegaly to cirrhosis and hepatopulmonary syndrome. Consequently, early detection and appropriate management are imperative for sustaining the health and influencing the quality of life of CF patients afflicted with CFLD. This review aims to consolidate existing knowledge by providing a comprehensive overview of hepatobiliary manifestations associated with CF. It delineates the clinical hepatobiliary manifestations, diagnostic methodologies, incorporating minimally invasive markers, and therapeutic approaches, encompassing the impact of novel CFTR modulators on CFLD. Given the exigency of early diagnosis and the intricate management of CFLD, a multidisciplinary team approach is essential to optimize care and enhance the quality of life for this subset of patients. In conclusion, recognizing CF as more than solely a pulmonary ailment, the authors underscore the imperative for further clinical investigations to establish a more robust evidence base for CFLD management within the continuum of this chronic disease.

The presence of cystic fibrosis-related diabetes modifies the sputum microbiome in cystic fibrosis disease

Cystic fibrosis-related diabetes (CFRD) affects 40%-50% of adults with CF and is associated with a decline in respiratory health. The microbial flora of the lung is known to change with the development of CF disease, but how CFRD affects the microbiome has not been described. We analyzed the microbiome in sputa from 14 people with CF, 14 with CFRD, and two who were classed as pre-CFRD by extracting DNA and amplifying the variable V3-V4 region of the microbial 16S ribosomal RNA gene by PCR. Sequences were analyzed and sources were identified to genus level. We found that the α-diversity of the microbiome using Shannon's diversity index was increased in CFRD compared with CF. Bray Curtis dissimilarity analysis showed that there was separation of the microbiomes in CF and CFRD sputa. The most abundant phyla identified in the sputum samples were Firmicutes and Proteobacteria, Actinobacteriota and Bacteroidota, and the ratio of Firmicutes/Bacteroidota was reduced in CFRD compared with CF. Pseudomonas, Azhorizophilus, Porphyromonas, and Actinobacillus were more abundant in CFRD compared with CF, whereas Staphylococcus was less abundant. The relative abundance of these genera did not correlate with age; some correlated with a decline in FEV1/FVC but all correlated with hemoglobin A1C (HbA1c) indicating that development of CFRD mediates further changes to the respiratory microbiome in CF.NEW & NOTEWORTHY Cystic fibrosis-related diabetes (CFRD) is associated with a decline in respiratory health. We show for the first time that there was a change in the sputum microbiome of people with CFRD compared with CF that correlated with markers of raised blood glucose.

What the future holds: cystic fibrosis and aging

Cystic fibrosis (CF) is one of the most common genetic diseases with around 70,000 affected patients worldwide. CF is a multisystem disease caused by a mutation in the CF transmembrane conductance regulator gene, which has led to a significant decrease in life expectancy and a marked impairment in the quality of life for people with CF (pwCF). In recent years, the use of highly effective CFTR modulator therapy (HEMT) has led to improved pulmonary function, fewer CF exacerbations, lower symptom burden, and increased weight. This has coincided with an increased life expectancy for pwCF, with mean age of survival being now in the 50s. This being a major breakthrough, which the CF population has hoped for, pwCF are now facing new challenges by growing old with a chronic respiratory disease. In this mini review, we are attempting to summarize the current knowledge of the aging process and its effect on CF disease and its manifestations including new developments, the current research gaps and potential future developments in the field to allow healthy aging for the CF community.

An Update in Cystic Fibrosis-Related Diabetes in Children and Adolescents

This paper delineates several aspects of cystic fibrosis-related diabetes (CFRD)-a common complication of cystic fibrosis (CF). CFRD exhibits a predilection for older individuals with CF, yet it also extends its influence on children and adolescents. Scientific insights postulate a potential link between CFRD and the aberrant mucus production within the pancreas, thereby culminating in pancreatic insufficiency. This, in turn, perturbs the synthesis of insulin, a pivotal endocrine hormone responsible for the regulation of glycemic levels. Standardized protocols advocate for the systematic screening of CFRD among all individuals with CF, commencing at the age of 10 years using the oral glucose tolerance test (OGTT). Therapeutic modalities encompass insulin therapy, dietary adjustments, and the vigilant monitoring of glycemic parameters. The overarching objective is to maintain blood glucose levels within a targeted range to mitigate the advent of diabetic complications. Untreated or sub-optimally managed CFRD can precipitate a spectrum of deleterious health ramifications, encompassing cardiovascular afflictions, neuropathy, renal dysfunction, and ocular complications.

Oxidative Stress Biomarkers in Cystic Fibrosis and Cystic Fibrosis-Related Diabetes in Children: A Literature Review

The most common inherited condition that results in death, particularly in those of Caucasian heritage, is cystic fibrosis (CF). Of all the young adults diagnosed with cystic fibrosis, 20% will develop hyperglycemia as a complication, later classified as a disease associated with cystic fibrosis. Impaired insulin secretion and glucose intolerance represent the primary mechanisms associated with diabetes (type 1 or type 2) and cystic fibrosis. Oxidative stress represents the imbalance between oxygen-reactive species and antioxidant defense mechanisms. This pathogenic mechanism is vital in triggering other chronic diseases, including cystic fibrosis-related diabetes. It is essential to understand oxidative stress and the significant impact it has on CFRD. This way, therapies can be individually adjusted and tailored to each patient's needs. This review aims to understand the connection between CFRD and oxidative stress. As a subsidiary element, we analyzed the effects of glycemic balance on complications and their evolution over time, providing insights into their potential benefits in mitigating oxidative stress-associated complications.

Spectrum of diabetes mellitus in patients with Shwachman-Diamond syndrome: case report and review of the literature

BACKGROUND

Shwachman-Diamond syndrome (SDS) is a rare congenital disorder caused by mutations in the SBDS gene and characterized by exocrine pancreatic deficiency, hematologic dysfunction, and skeletal growth failure. Although the hematologic features and characteristics of the somatic disorders commonly associated with SDS are well known, emerging data from case reports and patient registries suggest that SDS may also be associated with an increased risk of diabetes mellitus. However, currently available data on SDS-associated diabetes are limited and do not allow conclusions regarding prevalence and incidence rates, clinical course, and outcomes.

CASE PRESENTATION

Here we report the case of a 5-year-old girl with SDS who underwent bone marrow transplantation at the age of 3 months and developed autoantibody-positive type 1 diabetes mellitus at the age of 1.8 years. The manifestation and course of diabetes development were mild, complicated by concurrent spontaneous episodes of hypoglycemia even before the onset of antidiabetic treatment. Currently, adequate metabolic control can be achieved by dietary intervention.

CONCLUSIONS

Considering that the SBDS protein regulates mitosis and ribosomal biosynthesis and that its suppression may cause immunologic instability and chronic inflammation, this case provides insight into the phenotype of rare Shwachman-Diamond syndrome-associated diabetes mellitus, which may be characterized by significant age-dependent differences in clinical course.

The Effects of Elexacaftor, Tezacaftor, and Ivacaftor (ETI) on Blood Glucose in Patients With Cystic Fibrosis: A Systematic Review

Cystic fibrosis (CF) is an autosomal recessive genetic disorder resulting from defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which in turn results in a multi-systemic disorder. There are numerous known CF alleles associated with different mutations of the CFTR gene, with the most common CF allele being a three-base-pair deletion known as ΔF508. One common manifestation of CF is glycemic dysregulation associated with decreased insulin secretion, often progressing into a distinct form of diabetes known as cystic fibrosis-related diabetes (CFRD). In the past decade, a class of drugs known as CFTR modulators has entered clinical practice. These drugs interact with the CFTR protein to restore its function, with different modulators (or combinations of modulators) suitable for patients with different CFTR mutations. Previous research has established that the modulator ivacaftor is effective in decreasing blood glucose and sometimes resolving CFRD in patients with certain CFTR mutations (class III mutations). However, early modulator therapies for individuals with the common ΔF508 mutation (e.g., a combination of the modulators lumacaftor and ivacaftor) have largely proven ineffective in improving glucose regulation. More recently, a combination therapy of three modulators, namely elexacaftor, tezacaftor, and ivacaftor (ETI), has entered clinical practice for patients with the ΔF508 mutation. However, it is not clear whether this therapy is effective in treating dysglycemia. We searched for studies of any design that examined the effects of ETI on measures of blood glucose. All available studies were observational studies comparing patients before and after initiating ETI therapy. Measures of daily-life blood glucose (those obtained with continuous glucose monitoring systems or by measuring glycated hemoglobin (HbA1c)) and post-prandial glucose spikes from oral glucose tolerance tests showed significant improvements in at least some studies. The majority of studies showed significant improvements from pre- to post-ETI in one or more blood glucose measures. While the interpretation of this evidence is complicated by the lack of randomized controlled trials, it appears that ETI therapy is associated with improved glucose regulation for at least some patients with the ΔF508 mutation.

Evolving Nutritional Needs in Cystic Fibrosis

The course of cystic fibrosis (CF) as a nutritional illness is diverging since the introduction of highly effective modulator therapy, leading to more heterogeneous phenotypes of the disease despite CF genetic mutations that portend worse prognosis. This may become more evident as we follow the pediatric CF population into adulthood as some highly effective modulator therapies (HEMT) are approved for those as young as 1 year old. This review will outline the current research and knowledge available in the evolving nutritional health of people with CF as it relates to the impact of HEMT on anthropometrics, body composition, and energy expenditure, exocrine and endocrine pancreatic insufficiencies (the latter resulting in CF-related diabetes), vitamin and mineral deficiencies, and nutritional health in CF as it relates to pregnancy and lung transplantation.

Future Comorbidities in an Aging Cystic Fibrosis Population

Cystic fibrosis (CF) is an autosomal recessive disease due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. With the advent of highly effective modulator therapy targeting the abnormal CFTR protein, people with CF (PwCF) are living more than 40 years longer than the pre-modulator therapy era. As a result, PwCF are facing new challenges of managing similar comorbidities affecting the average aging population. While CF is notoriously identified as a chronic respiratory disease, the multisystem presence of the CFTR gene can contribute to other organ-related complications acutely, but also heighten the likelihood of chronic conditions not routinely encountered in this cohort. In this overview, we will focus on risk factors and epidemiology for PwCF as they relate to cardiovascular disease, dyslipidemia, CF-related diabetes, pulmonary hypertension, obstructive sleep apnea, CF-liver disease, bone health and malignancy. With increased awareness of diseases affecting a newly aging CF population, a focus on primary and secondary prevention will be imperative to implementing a comprehensive care plan to improve long-term morbidity and mortality.

A provider survey of cystic fibrosis related diabetes screening and management practices at North American CF centers

Background

Cystic Fibrosis Foundation (CFF) Guidelines recommend annual screening for cystic fibrosis related diabetes (CFRD) with an oral glucose tolerance test (OGTT). However, screening rates remain consistently low. We conducted surveys of 1) US CF center directors and 2) Endocrinologists affiliated with the CFF-sponsored EnVision program to characterize CFRD screening practices, describe provider perceived barriers to screening, and identify strategies for improving screening.

Methods

The surveys queried OGTT protocols, alternate screening strategies, and perceived barriers to screening. CF center characteristics and procedures for coordinating OGTTs were compared between centers achieving ≥50% versus <50% OGTT completion. Endocrinologists received additional questions regarding OGTT interpretation and management.

Results

The survey response rate was 18% (51/290) from CF Centers and 63% (25/40) from Endocrinologists. The majority (57%) of CF centers utilized 2 OGTT timepoints (0,120 min). The majority (72%) of Endocrinologists utilized 3 timepoints (0,60,120 min). Four percent of CF centers and 8% of Endocrinologists utilized other timepoints. Forty-nine percent of CF centers reported ≥50% OGTT completion in the past year. Completion of ≥50% OGTT was 5 times more likely when patient reminders were consistently provided (p = 0.017). Both CF Centers and Endocrinologists employed alternative screening strategies including HbA1c (64%, 92%), fasting plasma glucose (49%, 67%), continuous glucose monitoring (30%, 58%), and home fingerstick monitoring (55%, 50%).

Discussion

OGTT is the gold standard screening method for CFRD, but completion rates remain suboptimal, practice variation exists, and many providers utilize alternate screening strategies. Systematic reminders may improve completion rates. Studies to improve our approach to CFRD screening are urgently needed.

Improvements in Glucose Regulation in Children and Young People with Cystic Fibrosis-Related Diabetes following Initiation of Elexacaftor/Tezacaftor/Ivacaftor

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are increasingly used in children and young people with cystic fibrosis (CF). Data in adults show there may be an impact on glycaemic control in those with CF-related diabetes (CFRD). Paediatric data are rare. Case Series/Presentation: Children aged >12 years with CFRD, who were eligible for elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) were commenced on treatment. Glucose monitoring via the FreeStyle Libre system was commenced prior to, immediately after, and several months after commencing ELX/TEZ/IVA. Glycaemic control, shown by time in range (3-10 mmol/L), percentage of time spent hypoglycaemic (<3 mmol/L), and percentage of time spent hyperglycaemic (>10 mmol/L) on Insulin doses were recorded. Following ELX/TEZ/IVA, four of seven children stopped insulin, two required substantially reduced doses of insulin, one showed no response. Glycaemic control remained similar on lower doses or no insulin. Hypoglycaemia was detected in those not requiring insulin.

CONCLUSION

ELX/TEZ/IVA has a positive impact on glycaemic control and insulin requirements in children with CFRD. Close monitoring is required when commencing treatment. Children with CFRD need counselling regarding possible reductions in insulin requirement and re-education regarding symptoms, signs, and management of hypoglycaemia.

Inherited causes of exocrine pancreatic insufficiency in pediatric patients: clinical presentation and laboratory testing

Pediatric patients with exocrine pancreatic insufficiency (EPI) have symptoms that include abdominal pain, weight loss or poor weight gain, malnutrition, and steatorrhea. This condition can be present at birth or develop during childhood for certain genetic disorders. Cystic fibrosis (CF) is the most prevalent disorder in which patients are screened for EPI; other disorders also are associated with pancreatic dysfunction, such as hereditary pancreatitis, Pearson syndrome, and Shwachman-Diamond syndrome. Understanding the clinical presentation and proposed pathophysiology of the pancreatic dysfunction of these disorders aids in diagnosis and treatment. Testing pancreatic function is challenging. Directly testing aspirates produced from the pancreas after stimulation is considered the gold standard, but the procedures are not standardized or widely available. Instead, indirect tests are often used in diagnosis and monitoring. Although indirect tests are more widely available and easier to perform, they have inherent limitations due to a lack of sensitivity and/or specificity for EPI.

Diabetes is associated with increased burden of gastrointestinal symptoms in adults with cystic fibrosis

BACKGROUND

Individuals with diabetes mellitus (DM) are known to frequently experience gastrointestinal (GI) symptoms. In contrast, the impact of cystic fibrosis-related diabetes (CFRD) on accentuating GI symptoms in people with cystic fibrosis (pwCF) is unknown. We sought to examine this.

METHODS

Abdominal symptoms were measured using the validated CF-specific GI symptom questionnaire - CFAbd-Score© - as part of a multicentre cohort study in pancreatic insufficient adults with CF, not on cystic fibrosis transmembrane conductance regulator (CFTR) modulators. The CFAbd-Score total score (0-100pts), its 5 domains, alongside nine specific GI symptoms associated with DM, were compared between the CFRD and non-CFRD groups.

RESULTS

27 (31%) and 61 (69%) participants with CF were recruited in the CFRD and non-CFRD groups respectively. Total CFAbd-Score and the two domains: gastroesophageal reflux disease and disorders of appetite were significantly higher in the CFRD group compared to the non-CFRD group (p<0.05), with the mean total CFAbd-Score being 25.4 ± 2.5 and 18.4 ± 1.5 in the CFRD and non-CFRD groups respectively. Among the nine GI symptoms commonly reported as elevated in DM, bloating and nausea were significantly more common in individuals with CFRD compared to those without (p<0.05).

CONCLUSIONS

Individuals with CFRD overall, have a higher GI symptom burden, according to CFAbd-Scores. Specifically, they experience significantly more bloating and nausea. Close monitoring and further research is needed to better understand and manage GI symptoms in this group.

Transitions of Care in Cystic Fibrosis

The development of formal transition models emerged to reduce variability in care, including cystic fibrosis (CF) responsibility, independence, self-care, and education (RISE), which provides a standardized transition program, including knowledge assessments, self-management checklists, and milestones for people with CF. Despite these interventions, the current landscape of health care transition (HCT) remains suboptimal, and additional focused attention on HCT is necessary. Standardization of assessment tools to gauge the efficacy of transfer from pediatric to adult care is a high priority. Such tools should incorporate both clinical and patient-centered outcomes to provide a comprehensive picture of progress and deficiencies of the HCT process.

Bone metabolism and incretin hormones following glucose ingestion in young adults with pancreatic insufficient cystic fibrosis

Background

Gut-derived incretin hormones, including glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1), regulate post-prandial glucose metabolism by promoting insulin production. GIP, GLP-1, and insulin contribute to the acute bone anti-resorptive effect of macronutrient ingestion by modifying bone turnover. Cystic fibrosis (CF) is associated with exocrine pancreatic insufficiency (PI), which perturbs the incretin response. Cross-talk between the gut and bone ("gut-bone axis") has not yet been studied in PI-CF. The objectives of this study were to assess changes in biomarkers of bone metabolism during oral glucose tolerance testing (OGTT) and to test associations between incretins and biomarkers of bone metabolism in individuals with PI-CF.

Methods

We performed a secondary analysis of previously acquired blood specimens from multi-sample OGTT from individuals with PI-CF ages 14-30 years (n = 23). Changes in insulin, incretins, and biomarkers of bone resorption (C-terminal telopeptide of type 1 collagen [CTX]) and formation (procollagen type I N-terminal propeptide [P1NP]) during OGTT were computed.

Results

CTX decreased by 32% by min 120 of OGTT (P < 0.001), but P1NP was unchanged. Increases in GIP from 0 to 30 mins (rho = -0.48, P = 0.03) and decreases in GIP from 30 to 120 mins (rho = 0.62, P = 0.002) correlated with decreases in CTX from mins 0-120. Changes in GLP-1 and insulin were not correlated with changes in CTX, and changes in incretins and insulin were not correlated with changes in P1NP.

Conclusions

Intact GIP response was correlated with the bone anti-resorptive effect of glucose ingestion, represented by a decrease in CTX. Since incretin hormones might contribute to development of diabetes and bone disease in CF, the "gut-bone axis" warrants further attention in CF during the years surrounding peak bone mass attainment.

The utility of glucose area under the curve from the oral glucose tolerance test as a screening tool for cystic fibrosis-related diabetes

BACKGROUND

Consistently abnormal glucose levels on oral glucose tolerance test (OGTT) are the most effective screening tool for cystic fibrosis-related diabetes (CFRD). However, some cystic fibrosis (CF) patients demonstrate abnormal glucose profiles not reaching levels required for CFRD diagnosis and are, therefore, left untreated. Since CFRD is associated with disease deterioration, early diagnosis and treatment are desirable.

AIM

To explore the association between the area under the curve of glucose (G-AUC) obtained during a five-point 2-h standard OGTT and CF disease severity parameters.

METHODS

All CF patients referred for an annual routine OGTT at the Hadassah CF Center between 2002 and 2018, were included. Disease severity parameters were correlated with the G-AUC.

RESULTS

Two hundred forty-two OGTTs were performed in 81 patients (mean age 19.7 ± 9.0 years); 54% were normal, 14% showed impaired glucose tolerance (IGT), 5% had values in the indeterminate range (INDET), 11% had both IGT and INDET and 16% were diagnosed with CFRD. A gradual increase in mean G-AUC was observed among the groups. In multivariate regression models, G-AUC ≥ 295 mg h/dl was independently associated with an increased number of pulmonary exacerbations (PEx). Not all the patients having this value met the CFRD definition.

CONCLUSION

Patients who do not fulfill the criteria for CFRD may have abnormal glucose metabolism identifiable by abnormally high G-AUC values, which may be associated with more PEx. The potential advantage of treating these patients with insulin and the subsequent reduction in PEx needs further investigation.

Carbohydrate metabolism impairment in children and adolescents with cystic fibrosis

INTRODUCTION

Development of cystic fibrosis-related diabetes (CFRD) is associated with worsening of nutritional status and lung function, as well as increased mortality. The relevance of diagnosing the «pre-diabetic» status in these patients has not been addressed and the utility of HbA1c measurement in these patients is under discussion.

AIM

To study and characterise the different categories of carbohydrate metabolism impairment in paediatric patients with cystic fibrosis.

PATIENTS AND METHODS

A transversal study for characterisation of carbohydrate metabolism impairment according to clinical and anthropometric status and genetic background in 50 paediatric patients with cystic fibrosis (CF) was undertaken. Oral glucose tolerance tests (OGTT) for determination of glucose and insulin levels measurement and continuous subcutaneous glucose monitoring (CSGM) were performed.

RESULTS

6% of patients presented with CFRD, 26% impaired glucose tolerance, 10% an indeterminate glucose alteration and 2% impaired fasting glucose. The severity of glycaemic impairment correlated positively with age and negatively with standardised height (p < 0.05) with intergroup differences in HbA1c levels (p < 0.01), with the latter correlating with the duration of hyperglycaemia throughout CSGM. No intergroup differences in mutation prevalence, pulmonary function test, nutritional status or disease exacerbations in the previous year were found. The daily enzyme replacement dose correlated with the glucose area under the curve (AUC, p < 0.05) but not with insulin-AUC.

CONCLUSIONS

An older age and greater enzyme replacement need are correlated with more severe carbohydrate metabolism impairment and lower standardized height in paediatric CF patients, with HbA1c correlating with the duration of hyperglycaemia. The study of the full glucose/insulin AUCs throughout the OGTT affords no additional information compared to glucose determination at 120 min in these patients.

Pancreatic, hepatobiliary, and gastrointestinal manifestations of children with cystic fibrosis: A 10-year experience from a tertiary care center in southern India

OBJECTIVES

To describe the demography and spectrum of pancreatic, hepatobiliary, and gastrointestinal (GI) manifestations in children with cystic fibrosis (CF) from the Indian subcontinent.

METHODS

In this retrospective study, relevant information from the database of all children with CF below 18 years of age was collected and analyzed.

RESULTS

Among the total 109 children, 58 (53%) were from the southern states of India. The most common manifestation was pancreatic insufficiency (PI) in 85 (83%) children. Those with PI presented at an earlier age (1.8 vs. 6.9 years). Cirrhosis with portal hypertension was documented in only one patient and meconium ileus in three (2.8%). There was significant malnutrition in the PI cohort with a mean weight-for-age Z-score of - 3.17 ± 1.79 at diagnosis. Twenty-one (19%) patients had died during the follow-up and 18 (90%) of them had PI. There was no difference in the prevalence of selected pulmonary manifestations in the PI and pancreatic sufficient (PS) groups. Among children with PI, 78 were screened for ΔF508 mutation, 16 (21%) were homozygous, and 17 (22%) were heterozygous. In the PS group, only 2 (14%) were heterozygous for ΔF508 mutation. The median duration of follow-up of the patients was 1.8 (1.5) years.

CONCLUSION

PI is the most common GI manifestation of children with CF and is associated with severe malnutrition and poor outcome. Timely identification and management of the comorbidities involving the digestive system are essential for better growth and quality of life in these children.

Gene Polymorphism of Biotransformation Enzymes and Ciprofloxacin Pharmacokinetics in Pediatric Patients with Cystic Fibrosis

(1) Background: Ciprofloxacin (CPF) is widely used for the treatment of cystic fibrosis, including pediatric patients, but its pharmacokinetics is poorly studied in this population. Optimal CPF dosing in pediatric patients may be affected by gene polymorphism of the enzymes involved in its biotransformation. (2) Materials and Methods: a two-center prospective non-randomized study of CPF pharmacokinetics with sequential enrollment of patients (n-33, mean age 9.03 years, male-33.36%), over a period from 2016 to 2021. All patients received tablets of the original CPF drug Cyprobay® at a dose of 16.5 mg/kg to 28.80 mg/kg. Blood sampling schedule: 0 (before taking the drug), 1.5 h; 3.0 h; 4.5 h; 6.0 h; 7.5 h after the first dosing. CPF serum concentrations were analyzed by high performance liquid chromatography mass spectrometry. The genotype of biotransformation enzymes was studied using total DNA isolated from whole blood leukocytes by the standard method. (4) Results: a possible relationship between the CA genotype of the CYP2C9 gene (c.1075A > C), the GG genotype of the CYP2D6*4 gene (1846G > A), the AG genotype of the GSTP1 gene (c.313A > G), the GCLC* genotype 7/7 and the CPF concentration in plasma (increased value of the area under the concentration−time curve) was established. Conclusions: Gene polymorphism of biotransformation enzymes may affect ciprofloxacin pharmacokinetics in children.

Cystic Fibrosis-Related Diabetes in Poland

Cystic fibrosis (CF) is the most common autosomal recessive inherited monogenic disease in Caucasians. As medical technology progresses and the quality of patient care improves, the survival time of patients with CF has increased, which results in more frequent comorbidities such as cystic fibrosis-related diabetes (CFRD). CFRD is the result of abnormal glucose metabolism characterized primarily by insulin deficiency, exacerbated periodically by insulin resistance. The aim of our study was to analyze the epidemiology of patients with CFRD in Poland on the basis of data collected from six CF treatment centers. Analyses were performed on 1157 CF patients who were treated at one of the six CF care centers. CFRD was diagnosed according to standard criteria. All data including demographics, types of CFTR mutations, CFRD duration, and microorganisms in the sputum were obtained from the patients’ medical history. Our study indicates that the prevalence of CFRD in Poland is 12.9%. CFRD was most often diagnosed between the ages of 11 and 20 (60% of patients), while 23% of patients were diagnosed between 21 and 30 years of age. Furthermore, we observed that approximately 3–5% of patients under the age of 10 had CFRD. We found out that the type of mutation did not affect the frequency of CFRD development. Factors that increased the risk of developing CFRD include underweight and chronic Pseudomonas aeruginosa infection. Due to the extended lifespan of CF patients, the number of CFRD patients is currently increasing. We believe that the results of our study may complement information from other studies or may be useful in planning health policy in Poland.

Recipient selection, timing of referral, and listing for lung transplantation

Recipient selection for lung transplantation is a balance between providing access to transplantation to maximum patients, while utilizing this limited resource in the most optimal way. This review summarizes the current literature and recommendations about referral, listing, and evaluation of lung transplant candidates, with a focus on patients considered to have high risk characteristics.

Gestational and pregestational diabetes in pregnant women with cystic fibrosis

As cystic fibrosis transmembrane regulator (CFTR) modulator therapies offer greater longevity and improved health quality, women living with cystic fibrosis (CF) are increasingly pursuing pregnancy. Maternal risks for pregnant women with CF largely depend on a woman's baseline pulmonary and pancreatic function, and the majority of CF pregnancies will successfully end in live births. Diabetes, either gestational or pre-existing cystic fibrosis-related diabetes (CFRD), is highly prevalent in women with CF, affecting 18 to 62% of pregnancies in recent CF center reports. In addition to the rising incidence of CFRD with age, gestational diabetes is also more common in women with CF due to lower insulin secretion, higher insulin resistance, and increased hepatic glucose production as compared to pregnant women without CF. Diabetes occurring during pregnancy has important implications for maternal and fetal health. It is well established in women without CF that glycemic control is directly associated with risks of fetal malformation, neonatal-perinatal mortality, cesarean delivery and need for neonatal intensive care. Small studies in women with CF suggest that pregnancies affected by diabetes have an increased risk of preterm delivery, lower gestational age, and lower fetal birth weight compared to those without diabetes. Women with CF preparing for pregnancy should be counseled on the risks of diabetes and should undergo routine screening for CFRD with oral glucose tolerance testing (OGTT) if not already completed in the past six months. Glycemic control in those with pre-gestational CFRD should be optimized prior to conception. Insulin is preferred for the management of diabetes in pregnant women with CF via multiple daily injections or insulin pump therapy, and continuous glucose monitors (CGM) can be useful in mitigating hypoglycemia risks. Women with CF face many unique challenges impacting diabetes care during pregnancy and would benefit from support by a multidisciplinary care team, including nutrition and endocrinology, to ensure healthy pregnancies.

Optimising the care and quality of life of people with cystic fibrosis: the influence of cystic fibrosis transmembrane conductance regulator modulators

Cystic fibrosis is a life-limiting, inherited, multi-organ disease which affects many systems of the body. Until recently, treatments were only able to ameliorate symptoms, but the introduction of precision medications which modulate the underlying defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene has changed this. Notably improvements in nutrition and lung function, reduced use of antibiotics and reduced occupation rates for hospital beds have been seen. This article summarises the discussion of a group of healthcare professionals from different specialties and an expert patient, representing their personal views and experience of treating patients who are using CFTR modulators. The discussion was sponsored by an unrestricted grant from Chiesi Limited (Manchester, UK).

The β Cell in Diabetes: Integrating Biomarkers With Functional Measures

The pathogenesis of hyperglycemia observed in most forms of diabetes is intimately tied to the islet β cell. Impairments in propeptide processing and secretory function, along with the loss of these vital cells, is demonstrable not only in those in whom the diagnosis is established but typically also in individuals who are at increased risk of developing the disease. Biomarkers are used to inform on the state of a biological process, pathological condition, or response to an intervention and are increasingly being used for predicting, diagnosing, and prognosticating disease. They are also proving to be of use in the different forms of diabetes in both research and clinical settings. This review focuses on the β cell, addressing the potential utility of genetic markers, circulating molecules, immune cell phenotyping, and imaging approaches as biomarkers of cellular function and loss of this critical cell. Further, we consider how these biomarkers complement the more long-established, dynamic, and often complex measurements of β-cell secretory function that themselves could be considered biomarkers.

The Gut-Lung Axis in Cystic Fibrosis

Cystic fibrosis (CF) is a heritable, multiorgan disease that impacts all tissues that normally express cystic fibrosis transmembrane conductance regulator (CFTR) protein. While the importance of the airway microbiota has long been recognized, the intestinal microbiota has only recently been recognized as an important player in both intestinal and lung health outcomes for persons with CF (pwCF). Here, we summarize current literature related to the gut-lung axis in CF, with a particular focus on three key ideas: (i) mechanisms through which microbes influence the gut-lung axis, (ii) drivers of microbiota alterations, and (iii) the potential for intestinal microbiota remediation.

Management of chronic Pseudomonas aeruginosa infection with inhaled levofloxacin in people with cystic fibrosis

People with cystic fibrosis (CF) are highly susceptible to bacterial infections of the airways. By adulthood, chronic Pseudomonas aeruginosa (Pa) is the most prevalent infective organism and is difficult to eradicate owing to its adaptation to the CF lung microenvironment. Long-term suppressive treatment with inhaled antimicrobials is the standard care for reducing exacerbation frequency, improving quality of life and increasing measures of lung function. Levofloxacin (a fluoroquinolone antimicrobial) has been approved as an inhaled solution in Europe and Canada, for the treatment of adults with CF with chronic P. aeruginosa pulmonary infections. Here, we review the clinical principles relating to the use of inhaled antimicrobials and inhaled levofloxacin for the management of P. aeruginosa infections in patients with CF.

Academy of Nutrition and Dietetics: 2020 Cystic Fibrosis Evidence Analysis Center Evidence-Based Nutrition Practice Guideline

The Academy of Nutrition and Dietetics Evidence Analysis Center conducted a systematic review of the literature to develop an evidence-based practice guideline for primary nutrition issues in cystic fibrosis (CF). This guideline is designed to complement and build upon existing evidence-based CF nutrition guidelines. The objective of this guideline was to provide recommendations for registered dietitian nutritionists in the United States delivering medical nutrition therapy to individuals with CF and their families that fill gaps in current evidence-based guidelines on topics that are crucial in order to improve health and prevent disease progression. This guideline provides 28 nutrition recommendations to guide medical nutrition therapy, including nutrition screening, nutrition assessment, and dietary intake. For topics outside the scope of this guideline, practitioners are referred to external, evidence-based recommendations. The CF landscape is evolving rapidly with breakthroughs in cystic fibrosis transmembrane regulator modulators changing CF at a cellular level. Medical nutrition therapy for individuals with CF from infancy through advanced age requires novel and individualized approaches. The Academy Evidence Analysis Library CF guidelines provide a framework for expanding upon current knowledge to determine effective nutrition strategies for individuals with CF through long and healthy futures.

Anti-Inflammatory Influences of Cystic Fibrosis Transmembrane Conductance Regulator Drugs on Lung Inflammation in Cystic Fibrosis

Cystic fibrosis (CF) is caused by a defect in the cystic fibrosis transmembrane conductance regulator protein (CFTR) which instigates a myriad of respiratory complications including increased vulnerability to lung infections and lung inflammation. The extensive influx of pro-inflammatory cells and production of mediators into the CF lung leading to lung tissue damage and increased susceptibility to microbial infections, creates a highly inflammatory environment. The CF inflammation is particularly driven by neutrophil infiltration, through the IL-23/17 pathway, and function, through NE, NETosis, and NLRP3-inflammasome formation. Better understanding of these pathways may uncover untapped therapeutic targets, potentially reducing disease burden experienced by CF patients. This review outlines the dysregulated lung inflammatory response in CF, explores the current understanding of CFTR modulators on lung inflammation, and provides context for their potential use as therapeutics for CF. Finally, we discuss the determinants that need to be taken into consideration to understand the exaggerated inflammatory response in the CF lung.

Cystic Fibrosis Human Organs-on-a-Chip

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene: the gene product responsible for transporting chloride and bicarbonate ions through the apical membrane of most epithelial cells. Major clinical features of CF include respiratory failure, pancreatic exocrine insufficiency, and intestinal disease. Many CF animal models have been generated, but some models fail to fully capture the phenotypic manifestations of human CF disease. Other models that better capture the key characteristics of the human CF phenotype are cost prohibitive or require special care to maintain. Important differences have been reported between the pathophysiology seen in human CF patients and in animal models. These limitations present significant limitations to translational research. This review outlines the study of CF using patient-derived organs-on-a-chip to overcome some of these limitations. Recently developed microfluidic-based organs-on-a-chip provide a human experimental model that allows researchers to manipulate environmental factors and mimic in vivo conditions. These chips may be scaled to support pharmaceutical studies and may also be used to study organ systems and human disease. The use of these chips in CF discovery science enables researchers to avoid the barriers inherent in animal models and promote the advancement of personalized medicine.

Use of hemoglobin A1c to identify dysglycemia in cystic fibrosis

Background

Cystic fibrosis (CF) leads to pancreatic endocrine dysfunction with progressive glycemic disturbance. Approximately 30%–50% of people with CF eventually develop CF–related diabetes (CFRD). Pre-CFRD states progress from indeterminant glycemia (INDET) to impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). Screening guidelines recommend inconvenient annual 2-hour oral glucose tolerance tests (OGTTs), beginning at age 10 years. More efficient methods, such as hemoglobin A1C (HbA1c), have been evaluated, but only limited, relatively small studies have evaluated the association between HbA1c and pre-CFRD dysglycemic states.

Objective

To determine whether HbA1c is an appropriate screening tool for identifying patients with pre-CFRD dysglycemia to minimize the burden of annual OGTTs.

Methods

This retrospective review evaluated medical records data of all University of Massachusetts Memorial Health System CF patients with an HbA1c result within 90 days of an OGTT between 1997 and 2019. Exclusion criteria were uncertain CF diagnosis, other forms of diabetes, or incomplete OGTT. In total, 56 patients were included and categorized according to OGTT results (American Diabetes Association criteria): normal glucose tolerance, INDET, IFG, or IGT. Associations were evaluated between HbA1c and OGTT results and between HbA1c and pre-CFRD dysglycemic states.

Results

Mean HbA1c was not significantly different between patients with normal glucose tolerance and those in the INDET (p = 0.987), IFG (p = 0.690), and IGT (p = 0.874) groups. Analysis of variance confirmed the lack of association between HbA1c and glycemia, as mean HbA1c was not significantly different amongst the four categories (p = 0.250).

Conclusion

There is increasing awareness of the impact of pre-CFRD states, including reduced pulmonary function and nutritional status. Unfortunately, our results do not support using HbA1c as a screening tool for pre-CFRD dysglycemia, specifically INDET, IFG, and IGT. Further studies are warranted to evaluate more efficient screening methods to reduce the burden of annual OGTTs.

Animal Models and Their Role in Understanding the Pathophysiology of Cystic Fibrosis-Associated Gastrointestinal Lesions

The life expectancy of cystic fibrosis (CF) patients has greatly increased over the past decade, and researchers and clinicians must now navigate complex disease manifestations that were not a concern prior to the development of modern therapies. Explosive growth in the number of CF animal models has also occurred over this time span, clarifying CF disease pathophysiology and creating opportunities to understand more complex disease processes associated with an aging CF population. This review focuses on the CF-associated pathologies of the gastrointestinal system and how animal models have increased our understanding of this complex multisystemic disease. Although CF is primarily recognized as a pulmonary disease, gastrointestinal pathology occurs very commonly and can affect the quality of life for these patients. Furthermore, we discuss how next-generation genetic engineering of larger animal models will impact the field's understanding of CF disease pathophysiology and the development of novel therapeutic strategies.

[Cystic fibrosis being a polyendocrine disease (Review)]

The cystic fibrosis transmembrane regulator (CFTR) gene encodes the synthesis of a protein of the same name, which functions as a direct activator of anionic transport. Chloride is the most abundant anion; as an antagonist of Na+ and K+, it provides electroneutrality of cell membranes at rest; together with cations, it serves as an important osmolyte and forms water flow across cell membranes for transepithelial secretion.Glandular cells in CF trap Cl- and Na+, and the prodused secretion is excessively viscous. Subnormal CFTR activity leads to stagnation of mucociliary clearance, inhibition of intestinal transport.In addition to exocrine disorders, CFTR mutations are associated with a decrease in volume, mass, increased apoptosis of β-cells of the pancreas, a significant suppression of insulin exocytosis in response to stimulation with glucose and glucagon-like peptide-1, hyperglucagonemia against the background of a defect in the suppression of α-cell function by insulin, but a decrease in maximum capacity α-cells.Deficiency and progressive decline in bone mineral density is an expected secondary manifestation of CF due to pancreatic exocrine insufficiency with malabsorption of nutrients and fat-soluble vitamins. However, in patients with the F508del mutation, a significant decrease in the synthesis of OPG, COX-2, PGE2 in the osteoblastic formation, and an increase in the activity of the antianabolic NF-kB were found. We are talking about a defect in the canonical signaling pathway (Wnt/β-catenin), which regulates the expression of genes-activators of osteoblastogenesis, dissociation of the stages of physiological bone remodeling.In addition to congenital bilateral or unilateral aplasia of the vas deferens, an increase in the frequency of CFTR mutations is also found in non-obstructive azoospermia, oligo-, astheno- and teratospermia. CFTR is involved in the entry of HCO3- into Sertoli cells to trigger cAMP-dependent transcription and its defects lead to suppression of FSH-dependent gene expression of spermatogenesis, loss of sequence in the Wnt cascade, destruction of the PGE2-dependent transepithelial interaction and, as a consequence, the blood-testicular barrier.CF is characterized, along with classical signs, by endocrine dysfunction of the pancreas, osteoporosis with suppression of osteoblastogenesis, and a defect in spermatogenesis.

Cystic Fibrosis-Related Diabetes (CFRD): Overview of Associated Genetic Factors

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population and is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene that encodes for a chloride/bicarbonate channel expressed on the membrane of epithelial cells of the airways and of the intestine, as well as in cells with exocrine and endocrine functions. A common nonpulmonary complication of CF is cystic fibrosis-related diabetes (CFRD), a distinct form of diabetes due to insulin insufficiency or malfunction secondary to destruction/derangement of pancreatic betacells, as well as to other factors that affect their function. The prevalence of CFRD increases with age, and 40–50% of CF adults develop the disease. Several proposed hypotheses on how CFRD develops have emerged, including exocrine-driven fibrosis and destruction of the entire pancreas, as well as contrasting theories on the direct or indirect impact of CFTR mutation on islet function. Among contributors to the development of CFRD, in addition to CFTR genotype, there are other genetic factors related and not related to type 2 diabetes. This review presents an overview of the current understanding on genetic factors associated with glucose metabolism abnormalities in CF.

Managing Cystic Fibrosis related diabetes via telehealth during COVID-19 pandemic

Coronavirus disease 2019 (COVID-19) was declared a pandemic on March 11, 2020. In efforts to reduce the risk of transmission, telehealth visits for routine care has significantly increased in the United States. Cystic fibrosis patients have been categorized as a highly vulnerable population to COVID-19 infection. Cystic Fibrosis centers are rapidly assessing and responding to the pandemic to ensure the safety of CF patients. At our Cleveland Clinic Cystic Fibrosis center, we transitioned outpatient clinics to a virtual care model in March 2020. Here, we report the changes that were implemented to optimize diabetes management in CF patients through telehealth during the COVID-19 crisis.