Decreased lung function in female but not male subjects with established cystic fibrosis-related diabetes

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.

The associations between pediatric weight status and cystic fibrosis-related diabetes status and health-related quality of life among children and young adults with cystic fibrosis: A systematic review

BACKGROUND

Cystic fibrosis (CF) is a life-shortening genetic disease, yet life expectancy has recently increased, shifting the focus to disease management and health-related quality of life (HRQoL). Identification of clinical factors, such as weight status and CF-related diabetes (CFRD), that are associated with HRQoL can inform clinicians about the patient's health perception. The goal of this systematic review was two prong: identify the association of pediatric weight status and HRQoL and determine how CFRD status impacts HRQoL.

METHODS

A systematic review of published research was conducted following the methodology in the Cochrane Handbook on Systematic Reviews for Interventional Studies. Results were reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses. Risk of bias was assessed using the National Heart Lung & Blood Institute tool. A meta-analysis was not performed due to variability of the inclusion/exclusion criteria, differences in outcome reporting, and insufficient primary outcome data to pool.

RESULTS

Nine studies met inclusion criteria (n = 6 explored weight status and n = 3 studied CFRD), for a total of 1585 subjects (CFRD cases = 87). Pediatric weight status was positively associated with HRQoL, most commonly the Body Image and Eating Disturbance domains. CFRD was negatively associated with HRQoL, specifically the Treatment Burden and Weight domains.

CONCLUSIONS

Based on the limited data available, improved pediatric weight status appears to increase HRQoL while a CFRD diagnosis appears to decrease HRQoL. More research is needed to fully understand the role of these clinical factors on HRQoL, especially with life expectancy increasing among those with CF.

Acute and chronic non-pulmonary complications in adults with cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease that primarily affects the respiratory system and often leads to respiratory failure and premature death. Although pulmonary complications contribute to 85% of deaths, non-pulmonary complications are responsible for significant morbidity and mortality in adults with CF. Areas covered: This review summarizes acute and chronic non-pulmonary complications in CF patients, with emphasis on emerging complications and in the context of the current growth and aging of the CF adult population. It also addresses the potential benefits of CF transmembrane conductance regulator modulator therapy. Complications that occur after solid organ (e.g. lung and/or liver) transplantation have been excluded. The review is based on an extensive search of the available literature, using PubMed and international guidelines, and on the authors' clinical experience. Expert commentary: Acute non-pulmonary complications have been well described but should be recognized and managed carefully. Managing chronic non-pulmonary complications is an important and changing aspect of CF patient care, particularly with the emergence of novel complications in adults. Early detection of non-pulmonary complications is essential to the development of prevention and treatment strategies that aim to further improve the survival and health status of adult CF patients.

Continuous glucose monitoring in youth with cystic fibrosis treated with lumacaftor-ivacaftor

BACKGROUND

The effects of lumacaftor-ivacaftor therapy on glycemia have not been thoroughly investigated. Continuous glucose monitoring (CGM) provides detailed information about glycemic patterns and detects glucose abnormalities earlier than traditional screening tools for diabetes.

METHODS

CGM measures, HbA1c, and oral glucose tolerance test (OGTT) results were collected and within-subject results compared in F508del homozygous youth with CF before and after initiation of lumacaftor-ivacaftor using the Wilcoxon signed-rank test.

RESULTS

Nine youth with CF (6 males, median age 12.7 years) were enrolled. CGM was performed in all participants before (median 26 weeks) and after lumacaftor-ivacaftor (median 29 weeks). HbA1c and fasting plasma glucose increased (p = .02) after lumacaftor-ivacaftor initiation. No changes in OGTT 1 h or 2 h glucose nor CGM measures were observed overall. When analyzed by sex, males showed lower glycemic variability, as reflected by the mean amplitude of glycemic excursions, on the post-treatment CGM.

CONCLUSIONS

Glycemic abnormalities persisted in CF patients treated with lumacaftor-ivacaftor, although sex-dependent differences in glycemic response to treatment may exist.

Cystic Fibrosis-Related Diabetes

Cystic fibrosis (CF) is the most common autosomal recessive disorder in Caucasian populations. Individuals with CF have seen significant increases in life expectancy in the last 60 years. As a result, previously rare complications are now coming to light. The most common of these is cystic fibrosis-related diabetes (CFRD), which affects 40-50% of CF adults. CFRD significantly impacts the pulmonary function and longevity of CF patients, yet a lack of consensus on the best methods to diagnose and treat CFRD remains. We begin by reviewing our understanding of the pathogenesis of CFRD, as emerging evidence shows the cystic fibrosis transmembrane conductance regulator (CFTR) also has important roles in the release of insulin and glucagon and in the protection of β cells from oxidative stress. We then discuss how current recommended methods of CFRD diagnosis are not appropriate, as continuous glucose monitoring becomes more effective, practical, and cost-effective. Finally, we evaluate emerging treatments which have narrowed the mortality gap within the CF patient group. In the future, pharmacological potentiators and correctors directly targeting CFTR show huge promise for both CFRD and the wider CF patient groups.

SP-A2 contributes to miRNA-mediated sex differences in response to oxidative stress: pro-inflammatory, anti-apoptotic, and anti-oxidant pathways are involved

BACKGROUND

Human innate host defense molecules, surfactant protein A1 (SP-A1), and SP-A2 differentially affect the function and proteome of the alveolar macrophage (AM). We hypothesized that SP-A genes differentially regulate the AM miRNome.

METHODS

Humanized transgenic mice expressing SP-A1 and SP-A2 were subjected to O3-induced oxidative stress (OxS) or filtered air (FA), AMs were isolated, and miRNA levels were measured.

RESULTS

In SP-A2 males, we found significant changes in miRNome in terms of sex and sex-OxS effects, with 11 miRNAs differentially expressed under OxS. Their mRNA targets included BCL2, CAT, FOXO1, IL6, NF-kB, SOD2, and STAT3. We followed the expression of these transcripts as well as key cytokines, and we found that (a) the STAT3 mRNA significantly increased at 4 h post OxS and returned to baseline at 18 h post OxS. (b) The anti-oxidant protein SOD2 level significantly increased, but the CAT level did not change after 4 h post OxS compared to control. (c) The anti-apoptotic BCL2 mRNA increased significantly (18 h post OxS), but the levels of the other transcripts were decreased. The presence of the SP-A2 gene had a protective role in apoptosis of AMs under OxS compared to mice lacking SP-A (knockout, KO). (d) Pro-inflammatory cytokine IL-6 protein levels were significantly increased in SP-A2 mice compared to KO (4 and 18 h post OxS), which signifies the role of SP-A2 in pro-inflammatory protein expression. (e) SOD2 and CAT mRNAs changed significantly in OxS indicating a plausible role of SP-A2 in the homeostasis of reactive oxygen species. (f) Gonadectomy of transgenic mice showed that sex hormones contribute to significant changes of the miRNome expression.

CONCLUSIONS

We conclude that SP-A2 influences the miRNA-mediated sex-specific differences in response to OxS. In males, these differences pertain to inflammatory, anti-apoptotic, and anti-oxidant pathways.

Pulmonary Function and Sleep Breathing: Two New Targets for Type 2 Diabetes Care

Population-based studies showing the negative impact of type 2 diabetes (T2D) on lung function are overviewed. Among the well-recognized pathophysiological mechanisms, the metabolic pathways related to insulin resistance (IR), low-grade chronic inflammation, leptin resistance, microvascular damage, and autonomic neuropathy are emphasized. Histopathological changes are exposed, and findings reported from experimental models are clearly differentiated from those described in humans. The accelerated decline in pulmonary function that appears in patients with cystic fibrosis (CF) with related abnormalities of glucose tolerance and diabetes is considered as an example to further investigate the relationship between T2D and the lung. Furthermore, a possible causal link between antihyperglycemic therapies and pulmonary function is examined. T2D similarly affects breathing during sleep, becoming an independent risk factor for higher rates of sleep apnea, leading to nocturnal hypoxemia and daytime sleepiness. Therefore, the impact of T2D on sleep breathing and its influence on sleep architecture is analyzed. Finally, the effect of improving some pathophysiological mechanisms, primarily IR and inflammation, as well as the optimization of blood glucose control on sleep breathing is evaluated. In summary, the lung should be considered by those providing care for people with diabetes and raise the central issue of whether the normalization of glucose levels can improve pulmonary function and ameliorate sleep-disordered breathing. Therefore, patients with T2D should be considered a vulnerable group for pulmonary dysfunction. However, further research aimed at elucidating how to screen for the lung impairment in the population with diabetes in a cost-effective manner is needed.

The use of fructosamine in cystic fibrosis-related diabetes (CFRD) screening

OBJECTIVE

To determine whether serum fructosamine correlates with glycemic control and clinical outcomes in patients being screened for cystic fibrosis-related diabetes (CFRD).

METHODS

Fructosamine and percent predicted forced expiratory volume in 1s (FEV₁) were measured in patients undergoing a 2h oral glucose tolerance test (OGTT) for CFRD screening. Fractional serum fructosamine (FSF) was calculated as fructosamine/total protein.

RESULTS

FSF exhibited a positive correlation with 2h OGTT results (r²=0.3201, p=0.009), and ROC curve analysis suggested that FSF can identify patients with an abnormal OGTT (AUC=0.840, p=0.0002). FSF also exhibited a negative correlation with FEV₁ (r²=0.3732, p=0.035). Patients with FSF≥3.70μmol/g had significantly lower FEV₁ (median 47%) compared to those with FSF<3.70μmol/g (median 90%; p=0.015).

CONCLUSIONS

FSF correlated with both OGTT results and FEV₁, and reliably identified patients with abnormal OGTT results. This simple blood test shows potential as an effective tool in CFRD screening.

A Practical Approach to Glucose Abnormalities in Cystic Fibrosis

Cystic fibrosis is a common genetic condition and abnormal glucose handling leading to cystic fibrosis-related diabetes (CFRD) is a frequent comorbidity. CFRD is mainly thought to be the result of progressive pancreatic damage resulting in beta cell dysfunction and loss of insulin secretion. Whilst Oral Glucose Tolerance Testing is still recommended for diagnosing CFRD, the relationship between glucose abnormalities and adverse outcomes in CF is complex and occurs at stages of dysglycaemia occurring prior to diagnosis of diabetes by World Health Organisation criteria. Insulin remains the mainstay of treatment of CF-related glucose abnormalities but the timing of insulin commencement, optimum insulin regime and targets of glycaemic control are not clear. These complexities are compounded by common issues with nutritional status, need for enteral feeding, steroid use and high disease burden on CF patients.

Sex-specific IL-6-associated signaling activation in ozone-induced lung inflammation

Background

Acute ozone (O₃) exposure has known deleterious effects on the respiratory system and has been linked with respiratory disease and infection. Inflammatory lung disease induced by air pollution has demonstrated greater severity and poorer prognosis in women vs. men. Both severe damage to the bronchial-alveolar epithelium and malfunctioning of bronchial-blood barrier have been largely attributed to the pathobiology of O₃-induced inflammatory response, but the associated mechanisms in the male and female lung remain unknown.

Methods

Here, we investigated sex-based differential regulation of lung interleukin-6 (IL-6) and its downstream signaling pathways JAK2/STAT3 and AKT1/NF-κB in response to O₃ exposure in a mouse model. We exposed male and female mice (in different stages of the estrous cycle) to 2 ppm of O₃ or filtered air (FA) for 3 h, and we harvested lung tissue for protein expression analysis by Western blot.

Results

We found significant up-regulation of IL-6 and IL-6R in females and IL-6 in males in response to O₃ vs. FA. Ozone exposure induced a significant increase in STAT3-Y705 phosphorylation in both females and males. Males exposed to O₃ had decreased levels of JAK2, but increased JAK2 (Y1007+Y1008) phosphorylation, while females exposed to O₃ showed significant up-regulation of both proteins. Both NF-κB (p105/p50) and AKT1 protein levels were significantly increased only in females exposed to O₃. In addition, females exposed to O₃ during proestrus displayed increased expression of selected genes when compared to females exposed to O₃ in other estrous cycle stages.

Conclusions

Together, our observations indicate a sex-based and estrous cycle-dependent differential lung inflammatory response to O₃ and involvement of two converging JAK2/STAT3 and AKT1/NF-κB pathways. To our knowledge, this is the first study specifically addressing the impact of the estrous cycle in O₃-associated lung inflammatory pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s13293-016-0069-7) contains supplementary material, which is available to authorized users.

Glucose >200 mg/dL during Continuous Glucose Monitoring Identifies Adult Patients at Risk for Development of Cystic Fibrosis Related Diabetes

Rationale. Cystic fibrosis related diabetes (CFRD) is the most common comorbidity in patients with CF. In spite of increased screening, diagnosis, and treatment of CFRD, the mortality rate in patients with CFRD still far exceeds the mortality rate in those without CFRD. Guidelines suggest that screening for CFRD be performed annually using the 2-hour 75-gram oral glucose tolerance test (OGTT). Adherence to recommended screening has been poor, with only approximately one-quarter of adults with CF undergoing OGTT in 2014. Use of continuous glucose monitoring (CGM) for diagnosis may become an alternative. Objectives. Our objective was to determine whether abnormal CGM predicts subsequent development of CFRD, lung function, and body mass index (BMI) decline and increased rate of CF pulmonary exacerbations in adults with CF. Methods. In a prospective single center pilot trial from September 2009 to September 2010, 21 adult patients due for routine OGTT were recruited to complete simultaneous 3-day CGM and 2-hour 75 gram OGTT. Subsequently, clinical information was reviewed from 2008 to 2015. Conclusions. There was a moderate correlation between interpreted results of 2-hour OGTT and CGM (p = 0.03); CGM indicated a greater level of glucose impairment than OGTT. Glucose >200 mg/dL by CGM predicted development of CFRD (p = 0.0002).

Sex differences in the expression of lung inflammatory mediators in response to ozone

Sex differences in the incidence of respiratory diseases have been reported. Women are more susceptible to inflammatory lung disease induced by air pollution and show worse adverse pulmonary health outcomes than men. However, the mechanisms underlying these differences remain unknown. In the present study, we hypothesized that sex differences in the expression of lung inflammatory mediators affect sex-specific immune responses to environmental toxicants. We focused on the effects of ground-level ozone, a major air pollutant, in the expression and regulation of lung immunity genes. We exposed adult male and female mice to 2 ppm of ozone or filtered air (control) for 3 h. We compared mRNA levels of 84 inflammatory genes in lungs harvested 4 h postexposure using a PCR array. We also evaluated changes in lung histology and bronchoalveolar lavage fluid cell counts and protein content at 24 and 72 h postexposure. Our results revealed sex differences in lung inflammation triggered by ozone exposure and in the expression of genes involved in acute phase and inflammatory responses. Major sex differences were found in the expression of neutrophil-attracting chemokines (Ccl20, Cxcl5, and Cxcl2), the proinflammatory cytokine interleukin-6, and oxidative stress-related enzymes (Ptgs2, Nos2). In addition, the phosphorylation of STAT3, known to mediate IL-6-related immune responses, was significantly higher in ozone-exposed mice. Together, our observations suggest that a differential regulation of the lung immune response could be implicated in the observed increased susceptibility to adverse health effects from ozone observed in women vs. men.

The development of diabetes among Danish cystic fibrosis patients over the last two decades

OBJECTIVE

Cystic fibrosis (CF)-related diabetes (CFRD) is correlated with age and has been associated with a decline in body mass index (BMI), pulmonary function, and survival. Over the last two decades, the focus has been on the early diagnosis and treatment of diabetes; therefore, in this study, we evaluated the status of the current clinical condition and survival in our CF population. In addition, we also aimed to investigate the incidence of diabetes among adolescence over time and to identify characteristics associated with early diabetes onset.

METHODS

A retrospective chart review of a birth cohort consisting of 161 CF patients born between 1975 and 1994 and followed until 2011.

RESULTS

Over two decades, the incidence of CFRD among 11- to 16-year-old children remained unchanged at 12-14%, while the proportion of children with chronic pulmonary infection at age 10 declined from 31 to 8% (p < 0.001). Severe CF-mutation, i.e., group I and II mutations, were associated with diabetes (p = 0.003). Female gender was borderline associated with diabetes among adolescents (p = 0.06). No significant worsening in pulmonary function, BMI or survival was identified when comparing CFRD patients to CF patients without CFRD.

CONCLUSIONS

The incidence of diabetes among adolescence with CF has not changed over the last two decades. Severe CF mutations are a risk factor for CFRD, and female gender is borderline associated with CFRD among adolescents. Pulmonary function, BMI and survival were comparable regardless of the onset of CFRD.

Sputum glucose and glycemic control in cystic fibrosis-related diabetes: a cross-sectional study

Cystic fibrosis-related diabetes affects up to half of cystic fibrosis patients and is associated with increased mortality and more frequent pulmonary exacerbations. However, it is unclear to what degree good glycemic control might mitigate these risks and clinical outcomes have not previously been studied in relation to glucose from the lower airways, the site of infection and CF disease progression. We initially hypothesized that diabetic cystic fibrosis patients with glycosylated hemoglobin (HbA_1c) > 6.5% have worse pulmonary function, longer and more frequent exacerbations and also higher sputum glucose levels than patients with HbA_1c ≤ 6.5% or cystic fibrosis patients without diabetes. To test this, we analyzed spontaneously expectorated sputum samples from 88 cystic fibrosis patients. The median sputum glucose concentration was 0.70 mM (mean, 4.75 mM; range, 0-64.6 mM). Sputum glucose was not correlated with age, sex, body mass index, diabetes diagnosis, glycemic control, exacerbation frequency or length, or pulmonary function. Surprisingly, sputum glucose was highest in subjects with normal glucose tolerance, suggesting the dynamics of glycemic control, sputum glucose and pulmonary infections are more complex than previously thought. Two-year mean HbA_1c was positively correlated with the length of exacerbation admission (p < 0.01), and negatively correlated with measures of pulmonary function (p < 0.01). While total number of hospitalizations for exacerbations were not significantly different, subjects with an HbA_1c > 6.5% were hospitalized on average 6 days longer than those with HbA_1c ≤ 6.5% (p < 0.01). Current clinical care guidelines for cystic fibrosis-related diabetes target HbA_1c ≤ 7% to limit long-term microvascular damage, but more stringent glycemic control (HbA_1c ≤ 6.5%) may further reduce the short-term pulmonary complications.

Diabetes-related mortality in adults with cystic fibrosis. Role of genotype and sex

RATIONALE

Diabetes is associated with increased mortality in cystic fibrosis. Aggressive screening and early institution of insulin treatment significantly reduced this risk over the period of 1992-2008.

OBJECTIVES

To determine if progressive improvement in cystic fibrosis-related diabetes (CFRD) mortality has continued since 2008, and examine associations with CFTR genotypes linked to pancreatic insufficiency and to sex.

METHODS

Chart review was performed on 664 patients followed from 2008 to 2012.

MEASUREMENTS AND MAIN RESULTS

Overall mortality for patients with CFRD was 1.8 per 100 person-years, compared with 0.5 in patients with CF without diabetes (P = 0.0002); neither rate changed significantly from mortality reported for 2003-2008. Genotype impacted both mortality and diabetes risk: adults with severe CFTR genotypes experienced greater mortality at every age older than 32 years than those with mild genotypes (P = 0.002), and the risk of developing CFRD was also greatly increased in those with severe genotypes (prevalence 60% in adult patients with severe vs. 14% in adults with mild mutations). CFRD had a direct influence on mortality because it was associated with increased risk of death within each genotype category (20 vs. 2%, P = 0.007 for mild; 12 vs. 4%, P = 0.012 for severe). There was also a sex difference in adults with severe CFTR genotypes; both mortality and CFRD prevalence were higher at every age in females than males.

CONCLUSIONS

Despite substantial improvement over time, mortality for CFRD patients greater than 30 years remains higher than for patients with CF without diabetes.

Demographic, clinical, and laboratory parameters of cystic fibrosis during the last two decades: a comparative analysis

BACKGROUND

In recent years, patients with cystic fibrosis (CF) have tended to experience a longer life expectancy and higher quality of life. In this context, the aim of the present study was to evaluate and compare the demographic, clinical, and laboratory markers of patients with CF during the last two decades at a CF referral center.

METHODS

A retrospective study of the demographic, clinical, and laboratory markers for CF treatment at a CF referral center was performed during two decades: 2000 (DI, 1990-2000, n = 104 patients) and 2010 (DII, 2000-2010, n = 181 patients).

RESULTS

The following variables were less common in DI than in DII: (i) pancreatic insufficiency, (ii) meconium ileus, (iii) diabetes mellitus, (iv) Burkholderia cepacia colonization, (v) moderate and severe Shwachman-Kulczycki score (SKS), (vi) F508del mutation screening, (vii) patients without an identified CFTR mutation (class IV, V, or VI mutation), (viii) patients above the 10th percentile for weight and height, (ix) restrictive lung disease, and (x) older patients (p < 0.01). The following variables were more common in DI than in DII: (i) excellent and good SKS, (ii) F508del heterozygous status, (iii) colonization by mucoid and nonmucoid Pseudomonas aeruginosa, (iv) obstructive lung disease, and (v) minimal time for CF diagnosis (p < 0.01).

CONCLUSION

Clinical outcomes differed between the two decades. Demographic, clinical, and laboratory markers in patients with CF are useful tools and should be encouraged in CF referral centers to determine the results of CF management and treatment, enabling a better understanding of this disease and its clinical evolution. Early diagnosis and management of CF will improve patients' quality of life and life expectancy until personalized drug therapy is possible for all patients with CF.

Impact of sex on insulin secretion in cystic fibrosis

CONTEXT

Cystic fibrosis-related diabetes is primarily due to a defect in insulin secretion. Women with cystic fibrosis (CF) are at higher risk of developing CF-related diabetes.

OBJECTIVE

The objective of the study was to examine sex differences in insulin and glucose homeostasis. We hypothesized that in CF, women would display lower insulin secretion than men.

DESIGN

This was a study based on an ongoing observational CF cohort with a mean follow-up of 19.9 ± 5.2 months.

SETTING

The study was conducted at the CF clinic of the Centre Hospitalier de l'Université de Montréal (Québec, Canada).

PATIENTS

From 230 adults with CF (123 men, 107 women) of similar age and functional pulmonary status, 104 retested after the follow-up. Age-matched healthy individuals (25 men, 19 women) were included in the study.

INTERVENTIONS

Participants underwent a 2-hour oral glucose tolerance test with 30-minute interval sample measurements.

MAIN OUTCOME MEASURE

Plasma insulin and glucose levels were measured.

RESULTS

Women with CF had higher overall insulin secretion as compared with men with CF (P ≤ .05) but similar to healthy women (P = .606). Men with CF had lower overall insulin secretion than healthy men (P = .020) and higher insulin sensitivity (P = .009) than women with CF. PATIENTS with CF displayed higher overall glucose excursions than healthy patients. Sex-related differences were still observed in the CF cohort after follow-up.

CONCLUSIONS

Surprisingly, in CF, adult women presented higher insulin secretion than adult men at a comparable level with what is observed in healthy individuals. Potential implications of this sex dimorphism in CF remain to be established.

Transplanting the adolescent cystic fibrosis patient: can we do it?

Bilateral lung transplantation remains a treatment for end-stage cystic fibrosis (CF) lung disease when there is no further medical or surgical treatment available. The aim of lung transplantation is to improve patient life expectancy. The consensus view that lung transplantation extends life in children has been challenged. However, challengers have faced alternative explanations of their finding and it is largely accepted that lung transplantation in the adolescent patient population is an important treatment modality. The goal of this article is to address these concerns and assist with developing creative approaches to this known challenging subset of patients. The main focus of this article will be to discuss the looming question: what existing evidence or best practice insights could improve bilateral lung transplantation outcomes for adolescent patients with end-stage CF?

Gonadal hormones and oxidative stress interaction differentially affects survival of male and female mice after lung Klebsiella pneumoniae infection

Survival of mice after Klebsiella pneumoniae infection and phagocytosis by alveolar macrophages (AMs), in the presence or absence of ozone (O(3)) exposure prior to infection, is sex dependent. The objective of this work was to study the role of gonadal hormones, 5α-dihydrotestosterone (DHT) and 17β-estradiol (E(2)), on mouse survival after filtered air (FA) or O(3) exposure. Gonadectomized female (G×F) and male (G×M) mice implanted with control or hormone pellets (DHT in G×F, or E(2) in G×M), exposed to O(3) (2 ppm, 3h) or FA, and infected with K. pneumoniae were monitored for survival. Survival in G×F was identical after FA or O(3) exposure; in G×M O(3) exposure resulted in lower survival compared to FA. In O(3)-exposed females, gonadectomy resulted in increased survival compared to intact females or to G×M+E(2). A similar effect was observed in G×F+DHT. The combined negative effect of oxidative stress and hormone on survival was higher for E(2). Gonadectomy eliminated (females) or minimized (males) the previously observed sex differences in survival in response to oxidative stress, and hormone treatment restored them. These findings indicate that gonadal hormones and/or oxidative stress have a significant effect on mouse survival.

Slow-release insulin in cystic fibrosis patients with glucose intolerance: a randomized clinical trial

BACKGROUND

Early stages of glucose metabolism impairment are a period at risk in the long-term prognosis of cystic fibrosis (CF). Slow-release synthetic insulin glargine can be a therapeutic tool in this metabolic condition.

METHODS

In this phase 3 multicenter, controlled, two-arm, randomized clinical study, glargine was administered up to a dosage of 0.15 U/kg/die for a period of 18 months. Primary endpoint was the improvement of nutritional status [body mass index (BMI) Z score], while glucose tolerance [hemoglobin A1c (HbA1C) and respiratory function (FEV1 predicted] improvement were the secondary endpoints.

RESULTS

Thirty-four subjects (18 in the glargine arm and 16 in the control arm) were evaluated. Adherence to insulin treatment was excellent. No significant adverse events were reported. There were no significant differences in BMI, HbA1C and FEV1 values between the two groups nor within groups, except for HbA1C improvement in the glargine arm at month +18 (p = 0.04).

CONCLUSIONS

Glargine treatment was well accepted and tolerated. No real efficacy in improving clinical and glycometabolic conditions was demonstrated. Further studies are necessary to test glargine at higher dosage and for a longer follow-up period.

Pulmonary complications of endocrine and metabolic disorders

There are many important respiratory manifestations of endocrine and metabolic diseases in children. Acute and chronic pulmonary infections are the most common respiratory abnormalities in patients with diabetes mellitus, although cardiogenic and non-cardiogenic pulmonary oedema are also possible. Pseudohypoaldosteronism type 1 may be indistinguishable from cystic fibrosis (CF) unless serum aldosterone, plasma renin activity, and urinary electrolytes are measured and mutation analysis rules out CF. Hypo- and hyperthyroidism may alter lung function and affect the central respiratory drive. The thyroid hormone plays an essential role in lung development, surfactant synthesis, and lung defence. Complications of hypoparathyroidism are largely due to hypocalcaemia. Laryngospasm can lead to stridor and airway obstruction. Ovarian tumours, benign or malignant, may present with unilateral or bilateral pleural effusions. Metabolic storage disorders, primarily as a consequence of lysosomal dysfunction from enzymatic deficiencies, constitute a diverse group of rare conditions that can have profound effects on the respiratory system.

An overview of international literature from cystic fibrosis registries. Part 3. Disease incidence, genotype/phenotype correlation, microbiology, pregnancy, clinical complications, lung transplantation, and miscellanea

This is the third article related to a review of the literature based on data from national cystic fibrosis (CF) patient registries up to June 2008 and covering a total of 115 published studies. It focuses on several topics: CF incidence, genotype/phenotype correlation, microbiology, pregnancy/paternity, clinical complications, lung transplantation, and others. Seventy seven papers meeting the inclusion criteria were found to be related to the topics listed above. Another seven studies, already evaluated in previous papers of this series, were recalled for specific topics. Incidence is described by several studies, results being quite different from one country to another and quite inhomogeneous among regions within the same country. Studies on genetics address the genotype/phenotype correlation and look for a predictive value of CFTR mutations in terms of clinical outcome, with controversial results. Papers on microbiology describe the clinical relevance of different pathogens and their role in the progress of CF lung disease. A few articles give information on the features of CF women undergoing a pregnancy and try to identify the ones associated with a better outcome. Studies on clinical complications discuss prevalence and the role of haemoptysis, pneumothorax, CF related diabetes, ABPA and cancer. Papers on lung transplantation focus on models able to improve the selection criteria for transplantation candidates and the factors linked to post transplantation survival. Finally, several studies deal with a number of interesting topics related to CF epidemiology: clinical trial methodology, quality of care comparison among countries and centers, relationship between diagnosis and age/gender, and evaluation of pharmacological therapy. On the whole, CF Registries have already contributed to important advances in the knowledge of the natural history of CF, establishing the foundations for future improvement in CF research and care.

A methodology to establish a database to study gene environment interactions for childhood asthma

Background

Gene-environment interactions are likely to explain some of the heterogeneity in childhood asthma. Here, we describe the methodology and experiences in establishing a database for childhood asthma designed to study gene-environment interactions (PAGES - Paediatric Asthma Gene Environment Study).

Methods

Children with asthma and under the care of a respiratory paediatrician are being recruited from 15 hospitals between 2008 and 2011. An asthma questionnaire is completed and returned by post. At a routine clinic visit saliva is collected for DNA extraction. Detailed phenotyping in a proportion of children includes spirometry, bronchodilator response (BDR), skin prick reactivity, exhaled nitric oxide and salivary cotinine. Dietary and quality of life questionnaires are completed. Data are entered onto a purpose-built database.

Results

To date 1045 children have been invited to participate and data collected in 501 (48%). The mean age (SD) of participants is 8.6 (3.9) years, 57% male. DNA has been collected in 436 children. Spirometry has been obtained in 172 children, mean % predicted (SD) FEV₁ 97% (15) and median (IQR) BDR is 5% (2, 9). There were differences in age, socioeconomic status, severity and %FEV₁ between the different centres (p≤0.024). Reasons for non-participation included parents not having time to take part, children not attending clinics and, in a small proportion, refusal to take part.

Conclusions

It is feasible to establish a national database to study gene-environment interactions within an asthmatic paediatric population; there are barriers to participation and some different characteristics in individuals recruited from different centres. Recruitment to our study continues and is anticipated to extend current understanding of asthma heterogeneity.

Cystic fibrosis across Europe: EuroCareCF analysis of demographic data from 35 countries

BACKGROUND

A 35-country European cystic fibrosis (CF) demographic registry was developed to compare outcomes (EuroCareCF EC-FP6).

METHODS

We applied methods that had successfully created country-specific registries inviting wide participation to obtain consent and collate demographic and CFTR genotype data.

RESULTS

Among 29,095 patients, a widely different country-specific prevalence of childhood CF exists that cannot be explained by differential population frequency of mutant-CFTR or case under-ascertainment with a significant paucity of the homozygous p.Phe508del genotype that presents in childhood in >90% of cases.

CONCLUSIONS

Excess premature childhood CF mortality may still occur. The better resourced Western Europe now has a ~5% mortality for childhood CF, which is not apparent in many of the European countries reported here. In addition, a female survival disadvantage exists. The reasons require further investigation. We showcase the value of simple data collection in one rare disease, which might interest those managing rare diseases across the globe.

The how (and why) of disease registers

A disease register is central to the understanding of clinical outcomes but the principles underpinning register design are not always apparent. My group developed, implemented and analysed outcomes using cystic fibrosis (CF) registers in Scotland (~500 patients, 1992-1995), the UK (~7000 patients, 1995-2006) and more recently across Europe (~30 000 patients, 2006-2009). The key design principles are summarised and exemplified using the process required to add new diseases such as CF to neonatal screening programmes to illustrate pitfalls in the complex path from screening to timely entry into specialist CF care. The disciplines of screening and specialist CF disease therapy are very different and our findings may be relevant for the evaluation of the fragile links in the complex patient journey. Should these links fail, they have the potential to delay the entry of a screened baby into therapy after testing positive for a preventable disease.

[Value of continuous glucose monitoring in screening for diabetes in cystic fibrosis]

AIMS

In the past few years, survival has increased for people with cystic fibrosis (CF). Diabetes is an important complication of CF caused by pancreatic insufficiency, which reduces insulin secretion. Because of increased longevity of patients with CF, the prevalence of CF-related diabetes (CFRD) has increased. CFRD is associated with increased mortality and morbidity. Several studies have reported a decline in nutritional and pulmonary status 2-4 years before the diagnosis of CFRD. The introduction of insulin treatment can produce clinical improvement in weight and lung function. The oral glucose tolerance test is currently the reference method in screening for CFRD, but the current definition of diabetes based on the 2-h post-load plasma glucose level may not be the most accurate method for early detection of glucose tolerance abnormalities in CF. The continuous glucose monitoring system (CGMS) has been described as a useful tool for early detection of hyperglycemia in the CF patient. We tested the CGMS in CF patients with unexplained alteration of their general status. The aim of this study was to assess the value of the CGMS in this population.

METHODS

An annual OGTT (following World Health Organization recommendations) was conducted as a screening test to identify CFRD in patients aged over 10 years or patients aged under 10 years with a poorer clinical status. The CGMS was performed in patients with unexplained worsened clinical status and without diabetes in OGTT.

RESULTS

Forty-two patients aged from 8.5 to 19 years were screened using OGTT for CFRD. According to ADA criteria, 23 patients (54.8%) displayed normal glucose tolerance, 14 (33.3%) impaired glucose tolerance, and 5 diabetes (11.9%). Out of 37 nondiabetic, the CGMS was used in 20 patients with unexplained altered general status. The CGMS revealed peaks of glucose values greater than 2 g/L in 16 patients, 9 patients with normal glucose tolerance, and 7 patients with impaired glucose tolerance. The mean CGMS glucose and time of glycemic monitoring above 1.4 g/L increased in patients with peaks greater than 2 g/L compared to patients without peaks (p=0.0016 and p=0.0069 respectively). After analysis of the CGMS, the prevalence of diabetes increased from 11.9 to 50%. Three patients aged less than 10 years with a normal OGTT profile presented glycemic peaks greater than 2 g/L during CGMS.

CONCLUSION

CGMS revealed more glucose metabolism abnormalities than OGTT in patients with unexplained altered general status.

Cystic fibrosis-related diabetes: current trends in prevalence, incidence, and mortality

OBJECTIVE

Cystic fibrosis (CF)-related diabetes (CFRD) diagnosis and management have considerably changed since diabetes was first shown to be associated with a poor prognosis in subjects with CF. Current trends in CFRD prevalence, incidence, and mortality were determined from a comprehensive clinical database.

RESEARCH DESIGN AND METHODS

Data were reviewed from 872 CF patients followed at the University of Minnesota during three consecutive intervals: 1992-1997, 1998-2002, and 2003-2008.

RESULTS

CFRD is currently present in 2% of children, 19% of adolescents, and 40-50% of adults. Incidence and prevalence are higher in female subjects aged 30-39 years; otherwise, there are no sex differences. In younger individuals, CFRD without fasting hyperglycemia predominates, but fasting hyperglycemia prevalence rises with age. CFRD mortality has significantly decreased over time. From 1992-1997 to 2003-2008, mortality rate in female subjects dropped by >50% from 6.9 to 3.2 deaths per 100 patient-years and in male subjects from 6.5 to 3.8 deaths per 100 patient-years. There is no longer a sex difference in mortality. Diabetes was previously diagnosed as a perimorbid event in nearly 20% of patients, but of 61 patients diagnosed with diabetes during 2003-2008, only 2 died. Lung function but not nutritional status is still worse in CF patients with diabetes compared with those without diabetes. Nutritional status and pulmonary status are similar between patients without fasting hyperglycemia and those with fasting hyperglycemia.

CONCLUSIONS

Previously noted sex differences in mortality have disappeared, and the gap in mortality between CF patients with and without diabetes has considerably narrowed. We believe that early diagnosis and aggressive treatment have played a major role in improving survival in these patients.

Symposium 6: Young people, artificial nutrition and transitional care The nutritional challenges of the young adult with cystic fibrosis: transition

Cystic fibrosis (CF) is a complex multisystem disorder affecting mainly the gastrointestinal tract and respiratory system. Intestinal malabsorption occurs in approximately 90% of patients. In the past, malnutrition was an inevitable consequence of disease progression, leading to poor growth, impaired respiratory muscle function, decreased exercise tolerance and immunological impairment. A positive association between body weight and height and survival has been widely reported. The energy requirements of patients with CF vary widely and generally increase with age and disease severity. For many young adults requirements will be 120–150% of the age-related estimated average requirement. To meet these energy needs patients are encouraged to eat a high-fat high-energy diet with appropriate pancreatic enzyme supplements. Many patients are unable to achieve an adequate intake as a result of a variety of factors including chronic poor appetite, infection-related anorexia, gastro-oesophageal reflux and abdominal pain. Oral energy supplements and enteral tube feeding are widely used. Nutritional support has been shown to improve nutritional status and stabilise or slow the rate of decline in lung function. With such emphasis on nutritional intake and nutritional status throughout life, poor adherence to therapies and issues relating to body image are emerging. The median survival of patients with CF is increasing. CF is now considered a life-limiting disease of adulthood rather than a terminal childhood illness. With increased longevity new challenges are emerging that include the transition of young adults with CF to adult services, CF-related diabetes, disordered eating, osteoporosis, liver disease and transplantation.

Sex disparities in effects of cystic fibrosis-related diabetes on clinical outcomes: a matched study

BACKGROUND

Cystic fibrosis-related diabetes (CFRD) is an increasingly prevalent comorbidity factor for patients with cystic fibrosis (CF). CFRD has been associated with an accelerated decline in clinical parameters and an increased mortality rate.

OBJECTIVES

To investigate the clinical impact of CFRD on pulmonary function and clinical status using a matched study design to further explore potential causality.

METHODS

Charts from the adult CF clinic at St Paul's Hospital (Vancouver, British Columbia) were retrospectively reviewed. Forty CFRD patients with and without fasting hyperglycemia were matched to CF patients with nondiabetic glucose tolerance based on sex, age and forced expiratory volume in 1 s (FEV(1)).

RESULTS

Sixteen of 40 CFRD patients (40%) died compared with nine of 40 patient controls (23%) (P=0.13). CFRD patients were more likely to experience declines in FEV(1) (P<0.01), especially women (P<0.01). Patients with CFRD were not more likely to be hospitalized (P=0.39). Body mass index did not differ between groups.

CONCLUSIONS

Patients with CFRD had higher rates of FEV(1) deterioration than nondiabetic patients with CF, and showed a trend toward increased mortality. The present study suggests that CFRD has a significant clinical impact and should be carefully considered when evaluating the status of CF patients.

Genetic determinants and epidemiology of cystic fibrosis-related diabetes: results from a British cohort of children and adults

OBJECTIVE

Longer survival of patients with cystic fibrosis has increased the occurrence of cystic fibrosis-related diabetes (CFRD). In this study we documented the incidence of CFRD and evaluated the association between mutations responsible for cystic fibrosis and incident CFRD, while identifying potential risk factors.

RESEARCH DESIGN AND METHODS

This was a population-based longitudinal study of 50 cystic fibrosis speciality clinics in the U.K. Subjects included 8,029 individuals aged 0-64 years enrolled in the U.K. Cystic Fibrosis Registry during 1996-2005. Of these, 5,196 with data and without diabetes were included in analyses of incidence, and 3,275 with complete data were included in analyses of risk factors. Diabetes was defined by physician diagnosis, oral glucose tolerance testing, or treatment with hypoglycemic drugs.

RESULTS

A total of 526 individuals developed CFRD over 15,010 person-years. The annual incidence was 3.5%. The incidence was higher in female patients and in patients with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in classes I and II. In a multivariate model of 377 cases of 3,275 patients, CFTR class (relative risk 1.70 [95% CI 1.16-2.49], class I or II versus others), increasing age, female sex, worse pulmonary function, liver dysfunction, pancreatic insufficiency, and corticosteroid use were independently associated with incident diabetes.

CONCLUSIONS

The incidence of CFRD is high in Britain. CFTR class I and II mutations increase the risk of diabetes independent of other risk factors including pancreatic exocrine dysfunction.

Prior diabetes mellitus is associated with increased morbidity in cystic fibrosis patients undergoing bilateral lung transplantation: an 'orphan' area? A retrospective case-control study

BACKGROUND

The aim of this study was to determine whether pre-existing diabetes mellitus increases the risk of rejection, infection and/or death in cystic fibrosis patients undergoing bilateral sequential single-lung transplantation.

METHODS

A retrospective audit of 25 consecutive patients with cystic fibrosis who underwent bilateral sequential single-lung transplantation between 1 January 2003 and 31 December 2005 at a tertiary referral hospital was carried out.

RESULTS

Although 32% patients had diabetes diagnosed before lung transplantation, 92% had random blood glucose levels > or =11.1 mmol/L requiring insulin during admission. Patients with pre-existing diabetes had increased infection-related (3.9 vs 1.2, P= 0.01) and putative rejection-related (1.4 vs 0.5, P= 0.04) hospital admissions post-transplantation compared with those without diabetes pre-transplant. During the period of observation, four of eight patients with a prior diagnosis of diabetes died compared with none of 17 patients without prior diabetes (P= 0.0055).

CONCLUSION

Almost all cystic fibrosis patients develop hyperglycaemia after lung transplantation, but patients with prior diabetes have more complication-related admissions to hospital and a higher mortality rate.

The cystic fibrosis transmembrane recruiter the alter ego of CFTR as a multi-kinase anchor

This review focuses on a newly discovered interaction between protein kinases involved in cellular energetics, a process that may be disturbed in cystic fibrosis for unknown reasons. I propose a new model where kinase-mediated cellular transmission of energy provides mechanistic insight to a latent role of the cystic fibrosis transmembrane conductance regulator (CFTR). I suggest that CFTR acts as a multi-kinase recruiter to the apical epithelial membrane. My group finds that, in the cytosol, two protein kinases involved in cell energy homeostasis, nucleoside diphosphate kinase (NDPK) and AMP-activated kinase (AMPK), bind one another. Preliminary data suggest that both can also bind CFTR (function unclear). The disrupted role of this CFTR-kinase complex as ‘membrane transmitter to the cell’ is proposed as an alternative paradigm to the conventional ion transport mediated and CFTR/chloride-centric view of cystic fibrosis pathogenesis. Chloride remains important, but instead, chloride-induced control of the phosphohistidine content of one kinase component (NDPK, via a multi-kinase complex that also includes a third kinase, CK2; formerly casein kinase 2). I suggest that this complex provides the necessary near-equilibrium conditions needed for efficient transmission of phosphate energy to proteins controlling cellular energetics. Crucially, a new role for CFTR as a kinase controller is proposed with ionic concentration acting as a signal. The model posits a regulatory control relay for energy sensing involving a cascade of protein kinases bound to CFTR.

Economic implications of newborn screening for cystic fibrosis: a cost of illness retrospective cohort study

BACKGROUND

Newborn screening for cystic fibrosis might not be introduced if implementation and running costs are perceived as prohibitive. Compared with clinical diagnosis, newborn screening is associated with clinical benefit and reduced treatment needs. We estimate the potential savings in treatment costs attributable to newborn screening.

METHODS

Using the UK Cystic Fibrosis Database, we used a prevalence strategy to undertake a cost of illness retrospective snapshot cohort study. We estimated yearly costs of long-term therapies and intravenous antibiotics for 184 patients who were diagnosed as a result of screening as newborn babies, and 950 patients who were clinically diagnosed aged 1-9 years in 2002. Costs of adding cystic fibrosis screening to an established newborn screening service in Scotland were adjusted to 2002 prices and applied to the UK as a whole. Costs were recalculated in US$.

FINDINGS

Cost of therapy for patients diagnosed by newborn screening was significantly lower than equivalent therapies for clinically diagnosed patients: mean ($7228 vs $12 008, 95% CI of difference -6736 to -2028, p<0.0001) and median ($352 vs $2442, -1916 to -180, p<0.0001). When we limited the clinically diagnosed group to only those diagnosable with a 31 cystic fibrosis transmembrane regulator mutation assay and assumed similar disease progression in the clinically diagnosed group as in the newborn screening group, we showed that mean ($3,397,344) or median ($947,032) drug cost savings could have offset the estimated cost of adding cystic fibrosis to a UK national newborn screening service ($2,971,551).

INTERPRETATION

Including indirect costs savings, newborn screening for cystic fibrosis might have even greater financial benefits to society than our estimate shows. Clinical, social, and now economic evidence suggests that universal newborn screening programmes for cystic fibrosis should be adopted internationally.

Paediatric Northern Score centile charts for the chest radiograph in cystic fibrosis

AIM

To create the first national centile charts for the chest radiograph Northern Score using the UK Cystic Fibrosis (CF) Database (UKCFD).

MATERIALS AND METHODS

All active patients for 2002 from the UKCFD were analysed in 1-year cohorts from 0 to 18 years. Northern Score results from the annual review forms were used to construct centile lines for the 5th, 25th, 50th, 75th, 95th centiles.

RESULTS

There were 1806 patients with recorded Northern Score data for 2002 (927 male patients, male:female ratio 1.05). The centile chart demonstrates a quasi-linear rise throughout childhood. A Northern Score in excess of age in years equates to >95th centile in school-aged CF patients.

CONCLUSION

This centile chart provides a disease-specific reference range for monitoring individual patients or for evaluating therapeutic change using the dominant chest radiograph scoring system in the UK. Patients, parents and clinicians may find these useful during the annual review process.

Cystic fibrosis diagnosed after 2 months of age leads to worse outcomes and requires more therapy

OBJECTIVE

Newborn screening for cystic fibrosis remains controversial because improved pulmonary function has not been established. Studies to date have not accounted for differences in treatments delivered to clinically diagnosed children and newborn-screened controls. Here, we compare outcomes and treatment of patients clinically diagnosed within the newborn-screening reporting window (early-clinically diagnosed), those presenting after this period (late-clinically diagnosed), and patients diagnosed by newborn screening.

PATIENTS AND METHODS

In a cross-sectional analysis of cohorts retrospectively ascertained, patients who were homozygous deltaF508 with cystic fibrosis, attending specialist cystic fibrosis centers, and 1 to 10 years of age between 2000 and 2002 were identified from the United Kingdom Cystic Fibrosis Database and stratified into newborn-screened, early-clinically diagnosed, or late-clinically diagnosed cohorts. Two analyses were performed: (1) after restricting to the most recent year of data collection, early-clinically diagnosed and late-clinically diagnosed cohorts were matched to newborn-screened patients by patient age and year of data collection (133 patients per cohort were identified); and (2) for all years of data collection, annual sets of data for early-clinically diagnosed and late-clinically diagnosed patients were matched to newborn-screened patients by patient age and year of data collection (291 data sets per cohort were identified). Median height and weight z scores, proportion of patients with height and weight <10th percentile, prevalence of chronic Pseudomonas aeruginosa infection, Shwachman-Kulczyki morbidity scores, percent predicted forced expiratory volume in 1 second, and numbers of long-term therapies were compared.

RESULTS

In both analyses, newborn screening was associated with higher height z score, higher Shwachman-Kulczyki score, lower likelihood of height <10th percentile, and fewer long-term therapies compared with late-clinically diagnosed patients. No other differences were found.

CONCLUSIONS

Newborn screening was associated with improved growth, reduced morbidity, and reduced therapy, yet generated equivalent pulmonary outcome compared with late clinical diagnosis, suggesting that newborn screening may slow cystic fibrosis lung disease progression.