Recent advances in cystic fibrosis

The effect of the cystic fibrosis care center on outcomes after lung transplantation for cystic fibrosis

BACKGROUND

The purpose of this study was to evaluate outcomes in people with cystic fibrosis (CF) who underwent lung transplant (LT) at a transplant center with an accredited Cystic Fibrosis Care Center (CFCC) in the United States.

METHODS

We reviewed the Scientific Registry of Transplant Recipients for all adult patients with CF who received a first-time LT from 2005 to 2018. The primary outcome was graft failure. Unadjusted Kaplan-Meier analysis and adjusted multilevel Cox proportional hazards models were used to evaluate outcomes in CF patients undergoing lung transplantation at a CFCC.

RESULTS

2,573 patients with CF underwent a first time LT during the study period. Of the 68 lung transplantation centers, 50 were CFCCs (73.5%). After adjustment for potential confounders, patients who underwent lung transplantation at a hospital with an accredited CFCC had a 33% reduction in risk of death or re-transplantation compared to those transplanted at a hospital without an accredited CFCC (HR: 0.67, 95% CI: 0.56-0.82, p < 0.001).

CONCLUSIONS

People with CF who undergo LT at a transplant center with a CFCC have improved graft survival and decreased need for re-transplantation compared to those who undergo LT at a non-CFCC, independent of volume.

Assessment of p.Phe508del-CFTR functional restoration in pediatric primary cystic fibrosis airway epithelial cells

BACKGROUND

Mutations in the cystic fibrosis transmembrane regulator (CFTR) gene can reduce function of the CFTR ion channel activity and impair cellular chloride secretion. The gold standard method to assess CFTR function of ion transport using the Ussing chamber requires a high number of airway epithelial cells grown at air-liquid interface, limiting the application of this method for high throughput screening of potential therapeutic compounds in primary airway epithelial cells (pAECs) featuring less common CFTR mutations. This study assessed an alternative approach, using a small scale halide assay that can be adapted for a personalized high throughput setting to analyze CFTR function of pAEC.

METHODS

Pediatric pAECs derived from children with CF (pAECCF) were established and expanded as monolayer cultures, before seeding into 96-well plates for the halide assay. Cells were then transduced with an adenoviral construct containing yellow fluorescent protein (eYFP) reporter gene, alone or in combination with either wild-type CFTR (WT-CFTR) or p.Phe508del CFTR. Four days post transduction, cells were stimulated with forskolin and genistein, and assessed for quenching of the eYFP signal following injection of iodide solution into the assay media.

RESULTS

Data showed that pAECCF can express eYFP at high efficiency following transduction with the eYFP construct. The halide assay was able to discriminate functional restoration of CFTR in pAECCF treated with either WT-CFTR construct or the positive controls syntaxin 8 and B-cell receptor-associated protein 31 shRNAs.

SIGNIFICANCE

The current study demonstrates that the halide assay can be adapted for pediatric pAECCF to evaluate restoration of CFTR function. With the ongoing development of small molecules to modulate the folding and/or activity of various mutated CFTR proteins, this halide assay presents a small-scale personalized screening platform that could assess therapeutic potential of molecules across a broad range of CFTR mutations.

Characterization of primary rat nasal epithelial cultures in CFTR knockout rats as a model for CF sinus disease

OBJECTIVE

The objectives of the current experiments were to develop and characterize primary rat nasal epithelial cultures and evaluate their usefulness as a model of cystic fibrosis (CF) sinonasal transepithelial transport and CF transmembrane conductance regulator (CFTR) function.

STUDY DESIGN

Laboratory in vitro and animal studies.

METHODS

CFTR^+/+ and CFTR^-/- rat nasal septal epithelia (RNSE) were cultured on semipermeable supports at an air-liquid interface to confluence and full differentiation. Monolayers were mounted in Ussing chambers for pharmacologic manipulation of ion transport and compared to similar filters containing murine (MNSE) and human (HSNE) epithelia. Histology and scanning electron microscopy (SEM) were completed. Real-time polymerase chain reaction of CFTR^+/+ RNSE, MNSE, and HSNE was performed to evaluate relative CFTR gene expression.

RESULTS

Forskolin-stimulated anion transport (ΔIsc in μA/cm² ) was significantly greater in epithelia derived from CFTR^+/+ when compared to CFTR^-/- animals (100.9 ± 3.7 vs. 10.5 ± 0.9; P < 0.0001). Amiloride-sensitive I_SC was equivalent (-42.3 ± 2.8 vs. -46.1 ± 2.3; P = 0.524). No inhibition of CFTR-mediated chloride (Cl^- ) secretion was exhibited in CFTR^-/- epithelia with the addition of the specific CFTR inhibitor, CFTR_Inh -172. However, calcium-activated Cl^- secretion (UTP) was significantly increased in CFTR^-/- RNSE (CFTR^-/- -106.8 ± 1.6 vs. CFTR^+/+ -32.2 ± 3.1; P < 0.0001). All responses were larger in RNSE when compared to CFTR^+/+ and CFTR^-/- (or F508del/F508del) murine and human cells (P < 0.0001). Scanning electron microscopy demonstrated 80% to 90% ciliation in all RNSE cultures. There was no evidence of infection in CFTR^-/- rats at 4 months. CFTR expression was similar among species.

CONCLUSION

The successful development of the CFTR^-/- rat enables improved evaluation of CF sinus disease based on characteristic abnormalities of ion transport.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:E384-E391, 2017.

Medical and Surgical Advancements in the Management of Cystic Fibrosis Chronic Rhinosinusitis

PURPOSE OF REVIEW

The purpose of this review is to provide otolaryngologists with the most up-to-date advancements in both the medical and surgical management of CF-related sinus disease.

RECENT FINDINGS

Recent studies have supported more aggressive CRS management, often with a combination of both medical and surgical therapies. Comprehensive treatment strategies have been shown to reduce hospital admissions secondary to pulmonary exacerbations in addition to improving CRS symptoms. Still, current management strategies are lacking in both high-level evidence and standardized guidelines.

SUMMARY

The unified airway model describes the bi-directional relationship between the upper and lower airways as a single functional unit and suggests that CRS may play a pivotal role in both the development and progression of lower airway disease. Current strategies for CF CRS focus primarily on amelioration of symptoms with antibiotics, nasal saline and/or topical medicated irrigations, and surgery. However, there are no definitive management guidelines and there remains a persistent need for additional studies. Nevertheless, otolaryngologists have a significant role in the overall management of CF, which requires a multi-disciplinary approach and a combination of both surgical and medical interventions for optimal outcomes of airway disease. Here we present a review of currently available literature and summarize medical and surgical therapies best suited for the management of CF-related sinus disease.

Exploring the role and diversity of mucins in health and disease with special insight into non-communicable diseases

Mucins are major glycoprotein components of the mucus that coats the surfaces of cells lining the respiratory, digestive, gastrointestinal and urogenital tracts. They function to protect epithelial cells from infection, dehydration and physical or chemical injury, as well as to aid the passage of materials through a tract i.e., lubrication. They are also implicated in the pathogenesis of benign and malignant diseases of secretory epithelial cells. In Human there are two types of mucins, membrane-bound and secreted that are originated from mucous producing goblet cells localized in the epithelial cell layer or in mucous producing glands and encoded by MUC gene. Mucins belong to a heterogeneous family of high molecular weight proteins composed of a long peptidic chain with a large number of tandem repeats that form the so-called mucin domain. The molecular weight is generally high, ranging between 0.2 and 10 million Dalton and all mucins contain one or more domains which are highly glycosylated. The size and number of repeats vary between mucins and the genetic polymorphism represents number of repeats (VNTR polymorphisms), which means the size of individual mucins can differ substantially between individuals which can be used as markers. In human it is only MUC1 and MUC7 that have mucin domains with less than 40% serine and threonine which in turn could reduce number of PTS domains. Mucins can be considered as powerful two-edged sword, as its normal function protects from unwanted substances and organisms at an arm's length while, malfunction of mucus may be an important factor in human diseases. In this review we have unearthed the current status of different mucin proteins in understanding its role and function in various non-communicable diseases in human with special reference to its organ specific locations. The findings described in this review may be of direct relevance to the major research area in biomedicine with reference to mucin and mucin associated diseases.

Cationic antimicrobial peptides promote microbial mutagenesis and pathoadaptation in chronic infections

Acquisition of adaptive mutations is essential for microbial persistence during chronic infections. This is particularly evident during chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients. Thus far, mutagenesis has been attributed to the generation of reactive species by polymorphonucleocytes (PMN) and antibiotic treatment. However, our current studies of mutagenesis leading to P. aeruginosa mucoid conversion have revealed a potential new mutagen. Our findings confirmed the current view that reactive oxygen species can promote mucoidy in vitro, but revealed PMNs are proficient at inducing mucoid conversion in the absence of an oxidative burst. This led to the discovery that cationic antimicrobial peptides can be mutagenic and promote mucoidy. Of specific interest was the human cathelicidin LL-37, canonically known to disrupt bacterial membranes leading to cell death. An alternative role was revealed at sub-inhibitory concentrations, where LL-37 was found to induce mutations within the mucA gene encoding a negative regulator of mucoidy and to promote rifampin resistance in both P. aeruginosa and Escherichia coli. The mechanism of mutagenesis was found to be dependent upon sub-inhibitory concentrations of LL-37 entering the bacterial cytosol and binding to DNA. LL-37/DNA interactions then promote translesion DNA synthesis by the polymerase DinB, whose error-prone replication potentiates the mutations. A model of LL-37 bound to DNA was generated, which reveals amino termini α-helices of dimerized LL-37 bind the major groove of DNA, with numerous DNA contacts made by LL-37 basic residues. This demonstrates a mutagenic role for antimicrobials previously thought to be insusceptible to resistance by mutation, highlighting a need to further investigate their role in evolution and pathoadaptation in chronic infections.

Antimicrobial peptides (AMPs) are produced by the mammalian immune system to fight invading pathogens. The best understood function of AMPs is to interact with the membranes of microbes, thereby disrupting and killing cells. However, the amount of AMP available during chronic bacterial infections may not be sufficient to kill pathogens (sub-inhibitory). In this study, we found that at sub-inhibitory levels, AMPs promote mutations in bacterial DNA, a function not previously attributed to them. In particular, we found that in the bacteria Pseudomonas aeruginosa, one AMP called LL-37 can promote mutations, which enable the bacteria to overproduce a protective sugar coating, a process called mucoid conversion. P. aeruginosa mucoid conversion is a major risk factor for those suffering from cystic fibrosis (CF), the most common lethal, heritable disease in the US. We found that LL-37 is able to produce these mutations by penetrating the bacterial cell and binding to the bacterial DNA. DNA binding disrupts normal DNA replication and allows mutations to occur. Furthermore, we observed LL-37 induced mutagenesis in processes apart from mucoid conversion, in both P. aeruginosa and E. coli. This suggests that AMP-induced mutagenesis may be important for a broad range of chronic diseases and pathogens.

Surgical management of chronic rhinosinusitis in cystic fibrosis: a systematic review

BACKGROUND

The objective of this work was to systematically review literature on the effectiveness of surgical management for chronic rhinosinusitis (CRS) in cystic fibrosis (CF) patients.

METHODS

We performed a literature search encompassing the last 25 years in PubMed, Embase, and Cochrane CENTRAL. Inclusion criteria included English language papers containing original data, more than 6 subjects, and measurable clinical outcomes. Data was systematically collected on study design, patient demographics, clinical characteristics and outcomes, and level-of-evidence. Two investigators independently reviewed all manuscripts. A quality assessment of the included studies was performed.

RESULTS

The initial search yielded 416 abstracts, of which 24 articles met inclusion criteria, detailing 680 adult and pediatric CF patients who underwent surgical therapy. Surgical treatment included primarily endoscopic sinus surgery (ESS) (22/24). Outcome measures included sinonasal symptoms (14/24), endoscopic findings (8/24), pulmonary function testing (8/24), recurrence or revision surgery (5/24), hospitalization (4/24), need for antibiotic therapy (2/24), radiographic findings (2/24), and pulmonary exacerbations (1/24). The level-of-evidence was predominantly Level 4 (21/24); there were no Level 1 evidence studies. Most studies found improvement in symptom measures and endoscopic findings but no improvement in lower airway function after surgical therapy. Postoperative measures of the other outcomes were inconclusive or inconsistent.

CONCLUSION

For adult and pediatric CF sinusitis, ESS yielded clinical improvement as measured primarily by sinonasal symptoms and endoscopic findings. It is unclear if surgical intervention modifies lower airway disease. Future prospective studies with predetermined, objective, and validated outcome measures are needed to determine the effectiveness of surgical intervention for CF-related CRS. Overall evidence Grade B/C.

Sublingual Tacrolimus for Immunosuppression in Lung Transplantation

Lung transplantation has emerged as an option to prolong and increase the quality of life in patients with end-stage pulmonary lung disease. In lung transplant recipients, because of the high potential for acute and chronic allograft rejection, optimal selection, dosage and delivery of immunosuppressive medications is critical. Cystic fibrosis (CF), a multi-organ system disease that often includes pulmonary and gastrointestinal manifestations, represents the leading indication for bilateral lung transplantation. The gastrointestinal manifestations of CF, however, confound post-transplant management by causing significant variation in the rate and extent of absorption of orally administered immunosuppressive medications. Tacrolimus, a new calcineurin inhibitor, is increasingly employed as the primary immunosuppressive agent in lung transplant recipients. Unfortunately, tacrolimus itself exhibits variable bioavailability, particularly in CF transplant recipients. A novel approach to the absorption dilemma is administration of tacrolimus via the sublingual (SL) route. Little published information exists concerning the use of SL immunosuppression in transplant recipients. However, emerging evidence suggests that SL tacrolimus provides is an effective means of drug delivery particularly for CF lung transplant recipients. Preliminary results from a pilot study, demonstrate that SL delivery of tacrolimus achieves therapeutic serum levels, in lung transplant recipients with CF, over the first few postoperative months. In addition, the early postoperative use of SL tacrolimus has been associated with acceptable rates of transplant rejection and normal renal function in a cohort of 22 lung transplant recipients that included CF and non-CF transplant recipients. Potential pharmacokinetic advantages of the SL route of delivery include good permeability, rapid absorption, acceptable bioavailability and easy accessibility. From an economic standpoint, considerable cost savings could be achieved by using the SL rather than the intravenous route of drug delivery for tacrolimus. Comparative, prospective randomized trials are necessary to evaluate the long-term safety and efficacy of SL tacrolimus in lung transplant patients. Until such data are available, the use of SL tacrolimus should be considered in situations where alternative routes of delivery are unavailable or as part of ongoing research studies. Ultimately, SL tacrolimus may prove efficacious for short-term use in the early postoperative lung transplant recipients, particularly in patients with malabsorption problems such as CF transplant recipients.

Respiratory physiology on a chip

Our current understanding of respiratory physiology and pathophysiological mechanisms of lung diseases is often limited by challenges in developing in vitro models faithful to the respiratory environment, both in cellular structure and physiological function. The recent establishment and adaptation of microfluidic-based in vitro devices (μFIVDs) of lung airways have enabled a wide range of developments in modern respiratory physiology. In this paper, we address recent efforts over the past decade aimed at advancing in vitro models of lung structure and airways using microfluidic technology and discuss their applications. We specifically focus on μFIVDs covering four major areas of respiratory physiology, namely, artificial lungs (AL), the air-liquid interface (ALI), liquid plugs and cellular injury, and the alveolar-capillary barrier (ACB).

Challenges and directions: an analysis of Genetic Analysis Workshop 17 data by collapsing rare variants within family data

Recent studies suggest that the traditional case-control study design does not have sufficient power to discover rare risk variants. Two different methods—collapsing and family data—are suggested as alternatives for discovering these rare variants. Compared with common variants, rare variants have unique characteristics. In this paper, we assess the distribution of rare variants in family data. We notice that a large number of rare variants exist only in one or two families and that the association result is largely shaped by those families. Therefore we explore the possibility of integrating both the collapsing method and the family data method. This combinational approach offers a potential power boost for certain causal genes, including VEGFA, VEGFC, SIRT1, SREBF1, PIK3R3, VLDLR, PLAT, and FLT4, and thus deserves further investigation.

The use of DHPLC (Denaturing High Performance Liquid Chromatography) in II level screening of the CFTR gene in Prenatal Diagnosis

OBJECTIVE

The aim of the study is to evaluate the role of Denaturing High Performance Liquid Chromatography (DHPLC) in the second level screening of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene.

METHODS

A 9-month prospective study, between June 2008 and March 2009 at Artemisia Fetal Medical Centre, included 3829 samples of amniotic fluid collected from women undergoing mid-trimester amniocentesis.The genetic diagnosis of CF was based on research of the main mutations of the CFTR gene on fetal DNA extracted from the amniocytes, (first level screening) using different commercial diagnostic systems. A second level screening using DHPLC, on the amniotic fluid and on a blood sample from the couple, was offered in case of fetuses heterozygous at first level screening.

RESULTS

Of 3829 fetuses, 134 were found to be positive, 129 heterozygous and 5 affected. Of the 129 couples, following appropriate genetic counselling, 53 requested a second level screening. Through the use of DHPLC, 44 couples were found to be negative, and in nine couples, nine rare mutations were identified.

CONCLUSIONS

The first level screening can be useful to evidence up to 75% of the CF mutations. The second level screening can identify a further 10% of mutant alleles. DHPLC was found to be a reliable and specific method for the rapid identification of the rare CFTR mutations which were not revealed in initial first level screening.

[Infection in lung transplantation]

Actualmente, el trasplante de pulmón se considera un tratamiento válido para un buen número de pacientes con insuficiencia respiratoria grave. De todas formas, las complicaciones son muy frecuentes y pueden llevar a fracaso del injerto a medio y largo plazo y menor supervivencia. De acuerdo con el registro de la International Society for Heart and Lung Transplantation, las tasas de supervivencia al primer, segundo y quinto año fueron, en 2006, del 74, 65 y 47%, respectivamente. El principal obstáculo para el éxito a largo plazo del trasplante de pulmón es el rechazo crónico, caracterizado histológicamente como bronquiolitis obliterante, que acontece en cerca de dos terceras partes de los pacientes. Uno de los factores más importantes para el desarrollo de bronquiolitis obliterante, además del número de rechazos agudos, es la infección y la enfermedad por citomegalovirus (CMV). Recientemente, se ha destacado el papel de la infección por diferentes virus respiratorios como factores de riesgo para el desarrollo de rechazo crónico en receptores de un trasplante de pulmón. Las complicaciones infecciosas son una causa frecuente de morbimortalidad en este tipo de pacientes, y la causa de muerte de cerca de la mitad de ellos. La infección bacteriana es la complicación más frecuente de un receptor de un trasplante de pulmón. Del total, el 35-66% son bacterianas y el 50-85% de los pacientes presentan como mínimo un episodio de infección bacteriana. La segunda causa más frecuente de infección, después de la bacteriana, es la infección por CMV. A pesar de utilizar diferentes estrategias de prevención, la incidencia sigue siendo elevada, y se sitúa alrededor del 7% el primer año postrasplante. Es el único tipo de trasplante de órgano sólido en el cual la etiología más frecuente de la infección fúngica es Aspergillus spp., a diferencia del resto, en que típicamente se deben a Candida spp. La incidencia de aspergilosis invasora se cifra en alrededor del 4%.

Pseudomonas aeruginosa mucoid strain 8830 binds glycans containing the sialyl-Lewis x epitope

Pseudomonas aeruginosa infection of patients with cystic fibrosis (CF) is a leading cause of their morbidity and mortality. Pathogenesis is initiated in part by molecular interactions of P. aeruginosa with carbohydrate residues in airway mucins that accumulate in the lungs of patients with this disease. To explore the nature of the glycans recognized by a stable, mucoid, alginate-producing strain P. aeruginosa 8830 we generated a genetically modified Pa8830 expressing green fluorescent protein (Pa3380-GFP). We tested its binding to a panel of glycolipids and neoglycolipids in which selected glycans were covalently attached to dipalmitoyl phosphatidylethanolamine and analyzed on silica gel surfaces. Among all glycans tested, Pa8830-GFP bound best to sialyl-Le(x)-containing glycan NeuAc(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc-R and bound weakly to H-type blood group Fucalpha1-2Galbeta1-4GlcNAc-R, sialyl-lactose, and Le(x), and exhibited little binding toward non-fucosylated derivatives. Interestingly, while Pa8830-GFP bound to the glycosphingolipid asialoGM1, it did not appear to bind to a wide variety of other glycosphingolipids including GM1, GM2, asialoGM2, and sulfatide. These results indicate that P. aeruginosa 8830 has preferential binding to sialyl-Le(x)-containing glycans and has weak recognition of related fucose- and sialic acid-containing glycans. The finding that Pa8830 binds sialyl-Le(x)-containing glycans, which occur at increased levels in mucins from CF patients, is consistent with studies of other strains of P. aeruginosa and further suggests that such glycans on CF mucins contribute to disease pathogenesis.

[Will we still have antibiotics tomorrow?]

Since the discovery of antibiotics, it has been generally believed that these antimicrobials are capable of curing almost all bacterial infections. More recently, the appearance of increasing resistance to antibiotics and the emergence of multiresistant microorganisms have given rise to growing concern among physicians, and that concern has now started to filter through to society in general. The problem is further aggravated by a situation that not many people are currently aware of, that is, the limited prospects for future development of new antibiotics in the short to medium term. Appropriate use of available antibiotics based on a thorough understanding of their in vivo activity and the emergence of new forms of administration, such as inhalers, may help to alleviate the problem.

Work disability in adults with cystic fibrosis and its relationship to quality of life

With increasing numbers of cystic fibrosis (CF) patients surviving to adulthood, issues related to vocation inevitably arise and warrant specific attention. We examined the percentage of participants with CF currently working and explored risk factors for work disability among adults with CF.

METHOD

We recruited 50 consecutive patients from an adult cystic fibrosis service. Demographic, employment history, illness severity indicators and CF-attributed work disability factors were evaluated. Demographic risk factors for work disability using the illness severity measures of FEV(1), S-K score, CRDQ, and recent hospitalisation as independent variables were determined.

RESULTS

Factorial analysis of a disability index (DI) indicated no dependency on FEV(1) or S-K score, but dependency on quality of life indices (p<0.05), age (p<0.05) and hospital admission rate (p<0.05). Hours worked per week were dependent on quality of life (p<0.01) (mastery of disease domain), fewer hospital admissions (p<0.01) and age (p<0.05). Sixty-eight percent of the sample reported that CF resulted in significant impediments to employment. However, few had sought vocational guidance (6%).

CONCLUSION

Determinants of workforce participation shows that hours worked and perceived disability are more dependent on mastery of disease, age, and time in hospital, than on clinical severity scores. Health professionals may assist productivity through career counselling or tailored programs.

Management of frontal sinus mucoceles with posterior table erosion in the pretransplant cystic fibrosis population

BACKGROUND

Chronic rhinosinusitis has been described as a universal finding in cystic fibrosis (CF). Much of the literature has focused on pediatric population with a relative paucity of data on adult CF patients. In this report, we review our experience with management of frontal sinus mucoceles with posterior table (PT) erosion diagnosed by imaging in asymptomatic adult CF patients presenting for pretransplant evaluation.

STUDY DESIGN

Retrospective chart analysis.

MATERIALS AND METHODS

Adult CF patients presenting with frontal sinus mucoceles from January 2003 to December 2005 comprised the focus of the study. Charts were reviewed for age, sex, clinical presentation, culture results, complications, and outcome.

RESULTS

Fifty-nine CF patients undergoing lung transplant evaluation were seen in the outpatient rhinology clinic. Among these, 3 patients presented with asymptomatic frontal sinus mucoceles with PT erosion. The average age was 28.7 years (range, 23-38 years) and male-female ratio was 1:2. Two patients were managed with computer-aided endoscopic frontal sinusotomy during the pretransplant period. In the third patient, surgery was performed post transplantation when the patient was clinically stable. Intraoperative cultures grew Pseudomonas aeruginosa in all cases. No intraoperative surgical complications were encountered. One patient required overnight ventilatory support and was extubated successfully after 24 hours. Endoscopic patency of the frontal sinusotomy was confirmed at mean follow-up of 12.7 months (range, 4-22 months).

CONCLUSIONS

This preliminary report describes asymptomatic frontal sinus mucoceles with PT erosion in CF patients presenting for transplant evaluation. A high index suspicion must be maintained to avoid an inordinate delay in diagnosis given the potential risk of intracranial complications with this clinical entity.

Insulin-like growth factor-1, leptin, body composition, and clinical status interactions in children with cystic fibrosis

BACKGROUND/AIMS

Children with cystic fibrosis (CF) are of increased risk of reduced fat body mass (FBM) and lean body mass (LBM). Serum concentrations of insulin-like growth factor-1 (IGF-1)and leptin could be markers of LBM and/or FBM depletion. To evaluate the relationships between disease activity, body composition, IGF-1 and leptin concentrations in CF children.

METHODS

A cross-sectional study with 26 CF children aged 5.0-15.5 years and 33 healthy controls, mean age 9.4 years. Body composition was evaluated by dual-energy X-ray absorptiometry. Fasting blood samples were analyzed for leptin, IGF-1 and IGFBP-3.

RESULTS

FBM standard deviation score (SDS; CF boys -0.02 +/- 0.88 vs. 0.78 +/- 0.65, p < 0.01; CF girls -0.37 +/- 1.15 vs. 0.70 +/- 0.97, p < 0.05), leptin concentration (CF boys 2.07 +/- 0.79 vs. 3.07 +/- 1.28 ng/ml, p < 0.05; CF girls 2.71 +/- 0.86 vs. 5.00 +/- 2.95 ng/ml, p < 0.05) and IGF-1SDS (CF boys -1.43 +/- 1.50 vs. -0.32 +/- 0.88, p < 0.05; CF girls -0.66 +/- 1.66 vs. 0.64 +/- 0.57, p < 0.01) were lower in CF children compared to controls. Shwachman score was the strongest predictor of lean body mass (R = 0.63). Leptin levels explain 60% of the variability in FBM.

CONCLUSION

Serum concentrations of IGF-1 and leptin are decreased in children with CF and are associated with clinical conditions and body composition.

Sonographic findings of the genital tract in boys with cystic fibrosis

This pictorial review illustrates the findings in the sonographic examination of the male genital tract in children with cystic fibrosis (from newborn to age 12 years). We illustrate the variability in appearance and discuss the differences in findings from those in adult males with cystic fibrosis.

Variations of the CFTR gene in the Hanoi-Vietnamese

In order to investigate polymorphic backgrounds of the cystic fibrosis transmembrane conductance regulator gene (CFTR) in the Vietnamese, we analyzed 495 blood samples of randomly selected healthy individuals in Hanoi for the delta F508 mutation and TG-repeats, poly-T, and M470V polymorphisms. We compared their distributions with those of Caucasians and other Asian populations. No delta F508 mutation was found, being consistent with the extremely low incidence of cystic fibrosis (CF) in Vietnam. Allele frequency of the T5 allele promoting exon 9 skipping was 0.037. Greater number of TG-repeats, which is known to facilitate this aberrant splicing, was a predominant trend in the Vietnamese and other Asians. A "T5-TG12-V470" haplotype was most common (29/37) among T5-bearing haplotypes. Three major haplotypes, T7-TG12-M470, T7-TG11-V470, and T7-TG12-V470, estimated by PHASE program, related to 92% of the population. This is the first study of the CFTR gene among the Vietnamese.

[Technical aspects and relevance of energy expenditure and physical activity assessment in clinical research for cystic fibrosis patients]

Cystic fibrosis (CF) is characterized by deteriorating lung function and mal-digestion, which result in growth failure and/or under-nutrition. Several factors, alone or combined, contribute to malnutrition in CF: poor energy intake, elevation of energy loss as a result of malabsorption, increasing resting energy expenditure due to genetic mutation and/or pulmonary exacerbation. Several techniques have been used to assess energy expenditure and physical activity in order to better understand mechanisms of malnutrition in CF and follow therapeutic interventions. Indirect calorimetry (IC) studies have shown that resting energy expenditure (REE) was 10-22% higher than predictive values. This increase could be attributed to chronic inflammation as a result of Pseudomonas aeruginosa (PA) infection. Indeed, intravenous antibiotic therapy decreases REE. Doubly labelled water technique and heart rate monitoring calibrated against IC techniques shows that total energy expenditure (TEE) was not different than in healthy children. Physical activity level assessed by the ratio TEE-REE is also not different between CF of healthy children. Recently, new accelerometry technics, easier to use and less invasive have been successfully used in order to assess physical activity level in CF. Precise and ambulatory assessment of energy expenditure and physical activity permit to check and adapt dietary allowances in CF. These techniques could be simultaneously used and be helpful to assess efficacy of intervention studies.

Understanding the control of Pseudomonas aeruginosa alginate synthesis and the prospects for management of chronic infections in cystic fibrosis

Decades of research have been dedicated to the study of the opportunistic pathogen Pseudomonas aeruginosa, a Gram-negative, environmental bacterium that secretes the exopolysaccharide alginate during chronic lung infection of cystic fibrosis (CF) patients. Although P. aeruginosa utilizes a variety of factors to establish a successful infection in the lungs of CF patients, alginate has stood out as one of the best-studied prognostic indicators of chronic lung infection. While the genetics, biosynthesis and regulation of alginate are well understood, questions still remain concerning its role in biofilm development and its potential as a therapeutic target. The purpose of this review is to provide a brief summary of alginate biosynthesis and regulation, and to highlight recent discoveries in the areas of alginate production, biofilm formation and vaccine design. This information is placed in context with a proposed P. aeruginosa infectious pathway, highlighting avenues for the use of existing therapies as well as the potential for novel agents to reduce or eliminate chronic infections in CF patients.

A survey of sexual and reproductive health in men with cystic fibrosis: new challenges for adolescent and adult services

BACKGROUND

Improved survival dramatically alters the consequences of adult co-morbidities in men with cystic fibrosis (CF) such as male infertility. Few studies have systematically addressed the impact of sexual and reproductive health issues in these men or considered the implications for healthcare delivery.

METHOD

A descriptive cohort study was undertaken using a sexual and reproductive health survey of men from a large adult CF centre, including men with lung transplantation.

RESULTS

The mean (SD) age of the 94 men (response rate 75%) was 30.5 (7.6) years. 94% knew that men with CF had reduced fertility. Men first heard about infertility later than desired (p<0.001) and only 53% heard from their preferred source. Men who were told about infertility when older were more likely to be upset than those told earlier (p<0.01). 53% of men had undergone semen analysis: 68% of men who had not been tested wanted semen analysis. 73% believed semen analysis should occur before 18, but the youngest age of testing was 24 years. In adolescence, one in three men had assumed they did not need to use condoms and one in 10 had confused infertility with impotence. 66% of men wanted more information on reproductive options and 84% wanted children. Seventeen men were parents by natural conception (n = 1), micro-epididymal sperm aspiration (n = 6), donor sperm (n = 9), and through step children (n = 1).

CONCLUSIONS

Men with CF desire more sexual and reproductive health information. Earlier discussion of sexual and reproductive health is indicated in paediatric settings, and semen analysis should be routinely offered. In adult services greater discussion of reproductive health options is indicated.

Method for detection of respiratory viruses in the sputa of patients with cystic fibrosis

Since the role of respiratory viruses in lung exacerbations of patients with cystic fibrosis has been hampered by the difficulty of detecting viruses in viscous sputum specimens, a multiplex reverse transcriptase PCR (RT-PCR) assay combined with colorimetric amplicon detection was tested for the identification of seven common respiratory viruses in the sputa of cystic fibrosis patients. Of 52 sputa from 38 patients, 12 (23%) samples from 12 patients were positive for a respiratory virus (4 for influenza B, 3 for parainfluenza 1, 3 for influenza A and 2 for respiratory syncytial virus). These results suggest that the RT-PCR method carried out on sputum may provide a convenient means of investigating the role of virus infection in lung exacerbations of cystic fibrosis patients.

Relation between serum Insulin-like growth factor-I and insulin-like growth factor-binding protein-3 levels, clinical status and growth parameters in prepubertal cystic fibrosis patients

BACKGROUND

This study aims to determine the relation between anabolic hormones, Insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3), growth parameters, and clinical status in prepubertal cystic fibrosis (CF) patients. This prospective study comprises age/sex-matched control subjects and was set in a tertiary care teaching hospital.

METHODS

Serum concentrations of IGF-I and IGFBP-3 were measured in 37 CF and 23 healthy subjects, whose mean ages were 5.02 +/- 3.06 and 5.27 +/- 2.82, respectively. The results were analyzed in relation to body mass index standard deviation scores (BMISD), height standard deviation scores (HSD), growth velocity standard deviation scores (GVSD), and clinical status assessed by Shwachman scores and pulmonary function parameters.

RESULTS

Serum IGFBP-3 of CF patients showed significantly lower concentrations than healthy subjects (2457 vs. 3249 ng/mL) (P < 0.05), whereas IGF-I levels did not (123.35 vs. 149.8 ng/mL). There was significant positive correlation between IGF-I and IGFBP-3 with HSD (r = 0.62; r = 0.79) and BMISD (r = 0.39; r = 0.50). The pulmonary function tests in 14 CF subjects were not statistically worse than in nine healthy cases. The mean HSD (-0.67, SD 1.06) and BMISD (-0.28, SD 0.71) of CF patients were not significantly lower than those of healthy subjects (-0.02, SD 0.86 and 0.03, SD 0.49), respectively.

CONCLUSION

Decreased serum IGF-I and IGFBP-3 levels may reflect growth retardation in CF. IGFBP-3 seems like a more sensitive parameter than IGF-I for growth monitoring in this study. Growth parameters of Turkish prepubertal CF patients are not markedly below national standards. Different genetic backgrounds of relevant populations certainly play an important role for the variable clinical course.

Molecular analysis using DHPLC of cystic fibrosis: increase of the mutation detection rate among the affected population in Central Italy

BACKGROUND

Cystic fibrosis (CF) is a multisystem disorder characterised by mutations of the CFTR gene, which encodes for an important component in the coordination of electrolyte movement across of epithelial cell membranes. Symptoms are pulmonary disease, pancreatic exocrine insufficiency, male infertility and elevated sweat concentrations. The CFTR gene has numerous mutations (>1000) and functionally important polymorphisms (>200). Early identification is important to provide appropriate therapeutic interventions, prognostic and genetic counselling and to ensure access to specialised medical services. However, molecular diagnosis by direct mutation screening has proved difficult in certain ethnic groups due to allelic heterogeneity and variable frequency of causative mutations.

METHODS

We applied a gene scanning approach using DHPLC system for analysing specifically all CFTR exons and characterise sequence variations in a subgroup of CF Italian patients from the Lazio region (Central Italy) characterised by an extensive allelic heterogeneity.

RESULTS

We have identified a total of 36 different mutations representing 88% of the CF chromosomes. Among these are two novel CFTR mutations, including one missense (H199R) and one microdeletion (4167delCTAAGCC).

CONCLUSION

Using this approach, we were able to increase our standard power rate of mutation detection of about 11% (77% vs. 88%).

Macrolides in cystic fibrosis: is there a role?

A spectrum of anti-inflammatory properties, evidence of anti-infective action against Pseudomonas aeruginosa at sub-inhibitory concentrations and positive clinical experience in patients with diffuse panbronchiolitis, a disease with features in common with cystic fibrosis (CF), has prompted research to evaluate the role of macrolide therapy in patients with CF. Newer macrolides such as azithromycin have the advantage of improved tolerability and a prolonged intracellular half-life requiring an infrequent dosing regimen. Results from initial studies suggest a benefit from several months of macrolide therapy in patients with CF. An improvement in lung function was initially shown in a small open study in children, while maintenance of lung function compared with placebo, reduced acute respiratory exacerbations, and reduced systemic markers of inflammation were demonstrated in a randomized, placebo-controlled study of macrolide therapy in adult patients with CF. Additional controlled studies are required to determine optimal drug, dosage, and duration of therapy, and long-term adverse effects of prolonged therapy with macrolides in patients with CF. The potential, with long-term use, to induce resistance against other bacteria colonizing the upper respiratory tract e.g. pneumococci has not been explored. Measurement of cytokines and inflammatory mediators from the sputum of patients with CF is technically difficult and does not correlate with disease activity. There is a need for easily measurable, reproducible and clinically meaningful end-points for evaluation of new therapies in CF. The choice of appropriate outcome measures, apart from lung function, to monitor disease activity needs careful consideration in clinical trials determining the efficacy of macrolides in patients with CF. Evidence-based recommendations for the use of macrolides in the treatment of CF are not expected for some years although macrolides are already being prescribed for long-term use in some centers. There is a need for further research into mechanisms of anti-inflammatory action of macrolides in the lungs of patients with CF and whether or not such therapy may be beneficial in the long term.

Strategic challenges in neurotherapeutic pharmaceutical development

Developing new therapeutics presents formidable economic, scientific, and medical challenges that are exacerbated by special factors in neurotherapeutics development, e.g., the complexity of the CNS with its attendant need to sometimes affect multiple pathways, the lack of clarity of disease etiology, inadequacy of available animal models, and difficulties in defining disease populations and quantifying treatment response. This paper reviews the economic challenges faced by therapeutics developers in general and neurotherapeutics developers in particular. It discusses key scientific challenges, particularly those pertinent to neurotherapeutics development, as a background to proposing a different industrial strategy to drive future therapeutics development. This Biodesign strategy potentially surpasses previous paradigms by incorporating elements such as the use of disease modeling to select better targets and potential therapies, information science-based approaches to enhance small molecule chemistry, exploitation of the potential for biological technologies to rapidly generate mechanistic probes, and development of improved approaches for using animal models and studying human molecules mechanistically and biologically. Synergistic use of these elements can change the overall business model of companies engaged in neurotherapeutics development. The Biodesign paradigm has the potential to both markedly enhance the development of new therapies and to address some of the economic challenges facing healthcare systems and therapeutics developers alike.

Contemporary management of rhinosinusitis and cystic fibrosis

Historically, cystic fibrosis has been a devastating disease, with patients rarely living beyond childhood. Recent advances during the last two decades, however, have led to an improved understanding of the disease on a molecular level. Such understanding has in turn led to new treatments, longer life expectancy, as well as new challenges in the management of both pulmonary and extrapulmonary manifestations of cystic fibrosis. The otolaryngologist caring for patients with cystic fibrosis is thus challenged with the medical and surgical management of chronic sinusitis and sinonasal polyposis in these challenging circumstances.

Impact of intravenous antibiotic therapy on total daily energy expenditure and physical activity in cystic fibrosis children with Pseudomonas aeruginosa pulmonary exacerbation

Resting energy expenditure (REE) increases during pulmonary exacerbation by Pseudomonas aeruginosa in cystic fibrosis (CF) patients, and decreases after i.v. anti-Pseudomonas aeruginosa antibiotic therapy (IVAT). However, the impact of IVAT on total energy expenditure (TEE) is unknown. The aim of this study was to assess the changes in TEE and its main components after IVAT administered at home. Body composition measured by skinfold thickness and bio-impedance analysis, energy intake (EI) assessed by a weekly diary, REE measured by indirect calorimetry (IC), TEE assessed by a technique using 24-h heart-rate monitoring method and physical activity (PA) monitored using an activity diary (AD) were assessed in 16 patients (9 boys and 7 girls) aged 12.1 +/- 2.3 y (range, 7.1-14.6 y), before and after 28 +/- 4 d including a 14-d IVAT course. After IVAT, weight increased significantly by 1.9% (32.1 +/- 7.5 versus 32.7 +/- 7.6 kg; p < 0.05), while fat mass and fat free mass increased non significantly. EI increased by 4.6% (10,797 +/- 3039 versus 11320 +/- 3074 kJ/d; p < 0.05). TEE was not affected by IVAT (7014 +/- 1929 versus 7081 +/- 1478 kJ/d) whereas REE decreased by 4.1% (5295 +/- 909 versus 5093 +/- 837 kJ/d; p < 0.05), resulting in 9.3% increase in PA assessed by AD converted to metabolic equivalent tasks (MET) (37.0 +/- 3.1 versus 40.7 +/- 4.5 MET; p < 0.05). The improvement in nutritional status after IVAT is not related to a decrease in TEE, but probably to an increase in EI and a decrease of REE after IVAT. After IVAT, the reduction in REE is probably compensated by an increase in PA in CF patients.

Cost of care and clinical condition in paediatric cystic fibrosis patients

BACKGROUND

The clinical course of cystic fibrosis (CF) shows considerable variation resulting in differences in health care utilisation. We investigated important clinical parameters and their relation to costs.

METHODS

We collected clinical parameters together with health care utilisation of a representative paediatric CF population (n=138 patients) attending Hanover Medical School over a period of 1 year. 49% of the patients were chronically infected with Pseudomonas aeruginosa. Costs were calculated on the basis of the annual individual health care utilisation from the perspective of health insurance.

RESULTS

Total annual expenditure per patient amounted to 23,989 euro (S.D. 18,026), with home drug treatment representing the most important single cost factor (47% of total costs). While costs rose with age and doubled in the first 18 years, they correlated foremost with P. aeruginosa airway colonisation status and lung function expressed as FEV(1). Costs of patients with chronic P. aeruginosa infection were more than three times higher than of uninfected patients.

CONCLUSIONS

Health care expenditures for patients with CF vary with the clinical course. The variation can be explained to a large extend by clinical parameters.

Newborn screening for cystic fibrosis

Early diagnosis of cystic fibrosis (CF) provides an opportunity to improve disease control and prevent early complications. Of patients with CF in the United States, 10% are identified early through newborn screening (including infants born in Colorado, Massachusetts, New Jersey, New York, Wisconsin, Wyoming, and parts of California, Connecticut, Pennsylvania, and Montana). Successful screening programs in these states have stimulated other states to consider adding CF screening to their newborn programs. Additionally, new technology permits expanded screening for numerous genetic conditions. Genetic screening, such as that used most frequently for CF, creates new challenges for the clinician, including atypical disease presentations and carrier detection. In this review, we examine the many advances in CF newborn screening and early care that were reported during the last few years.

Urogenital abnormalities in male children with cystic fibrosis

BACKGROUND

Congenital bilateral absence of the vas deferens (CBAVD) is presumed to occur prenatally and is present in over 99% of adult males with cystic fibrosis (CF).

AIMS

To describe ultrasonic features in male children with CF. We aimed to describe urogenital anomalies, comparing pancreatic sufficient and insufficient CF patients.

METHODS

Pelvic and scrotal ultrasonography were performed in 12 boys with CF aged 2-12 years and 16 age matched healthy controls.

RESULTS

Nine patients had pancreatic insufficiency (PI): seven had two severe mutations and two had unknown mutations. Three boys were pancreatic sufficient (PS), two with splicing mutations (5T and 3849+10kb C-T respectively) and borderline sweat tests. Seminal vesicles were visualised in 5/12 patients and 8/16 controls, compared to non-visualisation reported in all adults with CBAVD. Testicular microlithiasis was found in 4/18 PI, 0/6 PS, and 0/32 control testes, compared to 0.6-1.4% in healthy males and 15% in CF adults; 7/18 PI, 4/6 PS, and 0/32 control testes were smaller than predicted for age. The epididymal head was non-homogeneous with cysts, hypo-, or hyper-echogenicity in 5/18 PI, 1/6 PS, and 0/32 control testes.

CONCLUSIONS

Genital abnormalities may occur early in CF, but are less common than described in adults. They are found more often in pancreatic insufficient than in pancreatic sufficient CF patients. However, a positive finding, if present, may aid in the diagnosis of the latter. A larger longitudinal study is recommended to better define the onset and progression of urogenital abnormalities.

Fine needle aspiration biopsy of thyroid nodules

BACKGROUND

Fine needle aspiration biopsy (FNA) is a routine diagnostic technique for evaluating thyroid nodules. Many reports in adults consider that FNA is superior to thyroid ultrasonography (USG) and radionuclide scanning (RS). Only five studies have been published on FNA of childhood thyroid nodules.

AIMS

To investigate the reliability of FNA in the evaluation and management of thyroid nodules, and compare the results of FNA, USG, and RS with regard to final histopathological diagnosis.

METHODS

FNA was performed in 46 children with thyroid nodules after USG and RS examination. We investigated the sensitivity, specificity, accuracy, and positive and negative predictive values of USG, RS, and FNA in their management.

RESULTS

Six patients who had malignant or suspicious cells on FNA examination underwent immediate surgery. The other 40 patients received medical treatment according to their hormonal status. Fifteen of these nodules either disappeared or decreased in number and/or size. Surgery was performed in 25 patients who did not respond to therapy. Statistical analysis revealed sensitivity, specificity, accuracy, and positive and negative predictive values respectively as follows: 60%, 59%, 59%, 15%, and 92% for USG; 30%, 42%, 39%, 12%, and 68% for SC; 100%, 95%, 95%, 67%, and 100% for FNAB.

CONCLUSION

FNAB is as reliable in children as in adults for definitive diagnosis of thyroid nodules. Using this technique avoids unnecessary thyroid surgery in children.