T cell developmental arrest in former premature infants increases risk of respiratory morbidity later in infancy

The inverse relationship between gestational age at birth and postviral respiratory morbidity suggests that infants born preterm (PT) may miss a critical developmental window of T cell maturation. Despite a continued increase in younger PT survivors with respiratory complications, we have limited understanding of normal human fetal T cell maturation, how ex utero development in premature infants may interrupt normal T cell development, and whether T cell development has an effect on infant outcomes. In our longitudinal cohort of 157 infants born between 23 and 42 weeks of gestation, we identified differences in T cells present at birth that were dependent on gestational age and differences in postnatal T cell development that predicted respiratory outcome at 1 year of age. We show that naive CD4+ T cells shift from a CD31-TNF-α+ bias in mid gestation to a CD31+IL-8+ predominance by term gestation. Former PT infants discharged with CD31+IL8+CD4+ T cells below a range similar to that of full-term born infants were at an over 3.5-fold higher risk for respiratory complications after NICU discharge. This study is the first to our knowledge to identify a pattern of normal functional T cell development in later gestation and to associate abnormal T cell development with health outcomes in infants.

Official American Thoracic Society Clinical Practice Guidelines: Diagnostic Evaluation of Infants with Recurrent or Persistent Wheezing

BACKGROUND

Infantile wheezing is a common problem, but there are no guidelines for the evaluation of infants with recurrent or persistent wheezing that is not relieved or prevented by standard therapies.

METHODS

An American Thoracic Society-sanctioned guideline development committee selected clinical questions related to uncertainties or controversies in the diagnostic evaluation of wheezing infants. Members of the committee conducted pragmatic evidence syntheses, which followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. The evidence syntheses were used to inform the formulation and grading of recommendations.

RESULTS

The pragmatic evidence syntheses identified few studies that addressed the clinical questions. The studies that were identified constituted very low-quality evidence, consisting almost exclusively of case series with risk of selection bias, indirect patient populations, and imprecise estimates. The committee made conditional recommendations to perform bronchoscopic airway survey, bronchoalveolar lavage, esophageal pH monitoring, and a swallowing study. It also made conditional recommendations against empiric food avoidance, upper gastrointestinal radiography, and gastrointestinal scintigraphy. Finally, the committee recommended additional research about the roles of infant pulmonary function testing and food avoidance or dietary changes, based on allergy testing.

CONCLUSIONS

Although infantile wheezing is common, there is a paucity of evidence to guide clinicians in selecting diagnostic tests for recurrent or persistent wheezing. Our committee made several conditional recommendations to guide clinicians; however, additional research that measures clinical outcomes is needed to improve our confidence in the effects of various diagnostic interventions and to allow advice to be provided with greater confidence.

[Clinical application of one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery]

Objective: To summarize the results and clinical application experience of one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery. Methods: From November 2014 to July 2016, 15 patients (9 males and 6 females) with ages ranging from 50 to 73 (63.5±6.2) years requiring cardiac surgery with bradycardia underwent one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery. All operations were performed under general anesthesia with chest median incision approach. Among them, single chamber pacemaker (n=10) and dual chamber pacemaker (n=5) permanent epicardial pacing leads were implanted. Simultaneous procedures included valve replacement in 7 cases, valve replacement combined with atrial fibrillation ablation in 3 cases, coronary artery bypass grafting in 2 cases, aortic root replacement in 2 cases, and valve replacement combined with coronary artery bypass surgery in 1 case. Their parameters of pacemaker including sensitivity, pacing threshold, pacing impedance were measured during surgery and closely followed up at 1 week and 3, 6 months after surgery. Results: All 15 patients with epicardial permanent pacemaker implantation in the same period of cardiac surgery were successfully cured and discharged, without any surgical complications. A total of 20 epicardial electrodes were implanted for them including 5 right atrial electrodes and 15 right ventricular electrodes. The postoperative follow-up period ranged from 3 to 22 months. No electrode fracture and surgical wound infection occurred in those patients, and their impedance, sensing and stimulation thresholds were all in normal ranges during follow-up. Conclusions: For patients with bradycardia who required cardiac surgery, one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery is safe and effective, and the results in the short-term and medium-term are satisfactory, avoiding the risk of staged surgery.

Cystic Fibrosis Transmembrane Conductance Regulator-Related Metabolic Syndrome and Cystic Fibrosis Screen Positive, Inconclusive Diagnosis

OBJECTIVE

An unintended consequence of cystic fibrosis (CF) newborn screening (NBS) is the identification of infants with a positive NBS test but inconclusive diagnostic testing. These infants are classified as CF transmembrane conductance regulator-related metabolic syndrome (CRMS) in the US and CF screen positive, inconclusive diagnosis (CFSPID) in other countries. Diagnostic and management decisions of these infants are challenges for CF healthcare professionals and stressful situations for families. As CF NBS has become more widespread across the world, increased information about the epidemiology and outcomes of these infants is becoming available. These data were reviewed at the 2015 CF Foundation Diagnosis Consensus Conference, and a harmonized definition of CRMS and CFSPID was developed.

STUDY DESIGN

At the consensus conference, participants reviewed published and unpublished studies of CRMS/CFSPID and used a modified Delphi methodology to develop a harmonized approach to the definition of CRMS/CFSPID.

RESULTS

Several studies of CRMS/CFSPID from populations around the world have been published in the past year. Although the studies vary in the number of infants studied, study design, and outcome measures, there have been some consistent findings. CRMS/CFSPID occurs relatively frequently, with CF:CRMS that ranges from 3 to 5 cases of CF for every 1 case of CRMS/CFSPID in regions where gene sequencing is not used. The incidence varies by NBS protocol used, and in some regions more cases of CRMS/CFSPID are detected than cases of CF. The majority of individuals with CRMS/CFSPID do not develop CF disease or progress to a diagnosis of CF. However, between 10% and 20% of asymptomatic infants can develop clinical features concerning for CF, such as a respiratory culture positive for Pseudomonas aeruginosa. Most studies have only reported short-term outcomes in the first 1-3 years of life; the long-term outcomes of CRMS/CFSPID remain unknown. The European CF Society definition of CFSPID and the CF Foundation definition of CRMS differ only slightly, and the consensus conference was able to create a unified definition of CRMS/CFSPID.

CONCLUSIONS

CRMS/CFSPID is a relatively common outcome of CF NBS, and clinicians need to be prepared to counsel families whose NBS test falls into this classification. The vast majority of infants with CRMS/CFSPID will remain free from disease manifestations early in life. However, a small proportion may develop clinical features concerning for CF or demonstrate progression to a clinical phenotype compatible with a CF diagnosis, and their long-term outcomes are not known. A consistent international definition of CRMS/CFSPID will allow for better data collection for study of outcomes and result in improved patient care.

Applying Cystic Fibrosis Transmembrane Conductance Regulator Genetics and CFTR2 Data to Facilitate Diagnoses

OBJECTIVE

As a Mendelian disease, genetics plays an integral role in the diagnosis of cystic fibrosis (CF). The identification of 2 disease-causing mutations in the CF transmembrane conductance regulator (CFTR) in an individual with a phenotype provides evidence that the disease is CF. However, not all variations in CFTR always result in CF. Therefore, for CFTR genotype to provide the same level of evidence of CFTR dysfunction as shown by direct tests such as sweat chloride or nasal potential difference, the mutations identified must be known to always result in CF. The use of CFTR genetics in CF diagnosis, therefore, relies heavily on mutation interpretation.

STUDY DESIGN

Progress that has been made on mutation interpretation and annotation was reviewed at the recent CF Foundation Diagnosis Consensus Conference. A modified Delphi method was used to identify consensus statements on the use of genetic analysis in CF diagnosis.

RESULTS

The largest recent advance in CF genetics has come through the Clinical and Functional Translation of CFTR (CFTR2) project. This undertaking seeks to characterize CFTR mutations from patients with CF around the world. The project also established guidelines for the clinical, functional, and population/penetrance criteria that can be used to interpret mutations not yet included in CFTR2's review.

CONCLUSIONS

The use of CFTR genetics to aid in diagnosis of CF requires that the mutations identified have a known disease liability. The demonstration of 2 in trans mutations known to always result in CF is satisfactory evidence of CFTR dysfunction. However, if the identified mutations are known to be associated with variable outcomes, or have unknown consequence, that genotype may not result in a CF phenotype. In these cases, other tests of CFTR function may help.

Diagnosis of Cystic Fibrosis: Consensus Guidelines from the Cystic Fibrosis Foundation

OBJECTIVE

Cystic fibrosis (CF), caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, continues to present diagnostic challenges. Newborn screening and an evolving understanding of CF genetics have prompted a reconsideration of the diagnosis criteria.

STUDY DESIGN

To improve diagnosis and achieve standardized definitions worldwide, the CF Foundation convened a committee of 32 experts in CF diagnosis from 9 countries to develop clear and actionable consensus guidelines on the diagnosis of CF and to clarify diagnostic criteria and terminology for other disorders associated with CFTR mutations. An a priori threshold of ≥80% affirmative votes was required for acceptance of each recommendation statement.

RESULTS

After reviewing relevant literature, the committee convened to review evidence and cases. Following the conference, consensus statements were developed by an executive subcommittee. The entire consensus committee voted and approved 27 of 28 statements, 7 of which needed revisions and a second round of voting.

CONCLUSIONS

It is recommended that diagnoses associated with CFTR mutations in all individuals, from newborn to adult, be established by evaluation of CFTR function with a sweat chloride test. The latest mutation classifications annotated in the Clinical and Functional Translation of CFTR project (http://www.cftr2.org/index.php) should be used to aid in diagnosis. Newborns with a high immunoreactive trypsinogen level and inconclusive CFTR functional and genetic testing may be designated CFTR-related metabolic syndrome or CF screen positive, inconclusive diagnosis; these terms are now merged and equivalent, and CFTR-related metabolic syndrome/CF screen positive, inconclusive diagnosis may be used. International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes for use in diagnoses associated with CFTR mutations are included.

Novel insights into the diagnostic and therapeutic challenges of the CFTR metabolic syndrome/CF screen positive indeterminate diagnosis

The growth of cystic fibrosis newborn screening (CF NBS) has led to an increased number of infants with a positive NBS test but inconclusive CF diagnostic testing. In the USA this condition is called CFTR related metabolic syndrome (CRMS), while in Europe the term CF screen positive, inconclusive diagnosis (CFSPID) is used. Recent advances in CF genetics and epidemiologic studies of CRMS/CFSPID have provided new insights into the prevalence and outcomes associated with this condition. Pediatr Pulmonol. 2016;51:S45-S48. © 2016 Wiley Periodicals, Inc.

Anti-coagulant therapy with dabigatran for cystic fibrosis patients

Patients with cystic fibrosis (CF) are at increased risk of venous thromboembolism, especially in association with central venous catheter use. Coumarin drugs and low molecular weight heparin are frequently used for anti-coagulant therapy, but are more challenging to administer in CF patients. Dabigatran, an oral thrombin antagonist, is an alternative anti-coagulant medication, but its use in CF has not been reported. We describe our experience in successfully using dabigatran for long-term anti-coagulation therapy in two CF patients. Our experience suggests that dabigatran can serve as an option for anticoagulation therapy in CF. Pediatr Pulmonol. 2016;51:E29-E30. © 2016 Wiley Periodicals, Inc.

Decline in lung function does not predict future decline in lung function in cystic fibrosis patients

BACKGROUND

Despite the attention paid to minimizing lung function decline among cystic fibrosis (CF) patients, the effect of rate of decline on subsequent disease progression is poorly understood. We aimed to describe the rate of decline of FVC, FEV1 , and FEF25-75 and to test the hypothesis that rate of decline of each spirometric variable predicts subsequent rate of decline in that variable and each other variable.

METHODS

Data were from the Epidemiologic Study of CF, an observational study of North American CF patients from 1994 to 2005. For each year of age, patients' best percent predicted FEV1 and associated FVC and FEF25-75, were used to calculate 2-year slopes for each spirometric variable. Pearson correlations were calculated between reference slopes and follow-up slopes up to 8 years later and, for FEV1 , between reference slopes and level (not slope) of lung function up to 5 years later.

RESULTS

Twenty six thousand, three hundred and ninety-three patients contributed 427,063 spirometries. Median 2-year slopes of all variables were negative for all ages >6 years and the magnitude varied with age, being greatest among 13-17 year olds, especially for FEF25-75 . There was no correlation (r < 0.10) between reference slopes and subsequent slopes 3-8 years later, either within or across variables. The correlation between 2-year FEV1 slopes and FEV1 level even 5 years later was moderate (0.37-0.49) across disease stage categories.

CONCLUSIONS

Contrary to our hypothesis, rate of lung function decline did not predict future rate of decline either within or across spirometric variables. In contrast, FEV1 slope did have moderate predictive ability for subsequent FEV1 level. These findings are relevant for clinical care and for clinical trial design.

Outcomes of infants with indeterminate diagnosis detected by cystic fibrosis newborn screening

BACKGROUND AND OBJECTIVES

Cystic fibrosis transmembrane conductance regulator-related metabolic syndrome (CRMS) describes asymptomatic infants with a positive cystic fibrosis (CF) newborn screen (NBS) but inconclusive diagnostic testing for CF. Little is known about the epidemiology and outcomes of CRMS. The goal of this study was to determine the prevalence, clinical features, and short-term outcomes of infants with CRMS.

METHODS

We analyzed data from the US CF Foundation Patient Registry (CFFPR) from 2010 to 2012. We compared demographic, diagnostic, anthropometric, health care utilization, microbiology, and treatment characteristics between infants with CF and infants with CRMS.

RESULTS

There were 1983 infants diagnosed via NBS between 2010 and 2012 reported to the CFFPR. By using the CF Foundation guideline definitions, 1540 and 309 infants met the criteria for CF and CRMS, respectively (CF:CRMS ratio = 5.0:1.0). Of note, 40.8% of infants with CRMS were entered into the registry with a clinical diagnosis of CF. Infants with CRMS tended to have normal nutritional indices. However, 11% of infants with CRMS had a positive Pseudomonas aeruginosa respiratory tract culture in the first year of life.

CONCLUSIONS

CRMS is a common outcome of CF NBS, and some infants with CRMS may develop features concerning for CF disease. A substantial proportion of infants with CRMS were assigned a clinical diagnosis of CF, which may reflect misclassification or clinical features not collected in the CFFPR.

Early childhood wheezing is associated with lower lung function in cystic fibrosis

OBJECTIVE

To study the association between wheezing in children with cystic fibrosis (CF) and lung function in later life.

METHODS

We used data from the Epidemiologic Study of CF, a longitudinal observational study from 1994 to 2005. Wheezing phenotypes were defined as: no wheezing in the first 6 years of life (NW), transient wheezing (TW; wheezing <3 years old, but no wheezing after 3), late wheezing (LW; wheezing only after age 3 years), and persistent wheezing (PW; wheezing both before and after age 3 years). A linear regression model was developed predicting the best forced expiratory volume in 1 sec (FEV1 ) at age 6 or 7 years (6 to <8) for each wheezing phenotype.

RESULTS

A total of 1302 children met the cohort inclusion criteria; 61% of the cohort had wheezing in the first 6 years of life. A history of any wheezing in the first 6 years of life was associated with a significantly lower FEV1 at 6 to <8 years compared to children with NW. The FEV1 of children with NW at age 6 to <8 years was 104% predicted, whereas the mean FEV1 in TW, LW, and PW groups was 98%, 100%, and 96% predicted, respectively (P < 0.05 compared to NW).

CONCLUSIONS

Childhood wheezing in CF is common and is associated with lower lung function at age 6 to <8 years. Our results identify a clinical feature in early childhood CF associated with lower lung function in later life.

Treatment complexity in cystic fibrosis: trends over time and associations with site-specific outcomes

BACKGROUND

Patients with cystic fibrosis (CF) have increasing treatment complexity and high treatment burden. We describe trends in treatment complexity and evaluate its relationship with health outcomes.

METHODS

Using Epidemiologic Study of Cystic Fibrosis (ESCF) data, we developed a treatment complexity score (TCS) from 37 chronic therapies and assessed change by age group (6-13, 14-17, and 18+ years) over a three year period. Differences in average site TCS were evaluated by quartiles based on FEV1, BMI, or Treatment Burden score on the Cystic Fibrosis Questionnaire-Revised (CFQ-R).

RESULTS

TCS scores were calculated for 7252 individual patients (42% child, 16% adolescent, 43% adult) across 153 sites. In 2003, mean TCS was 11.1 for children, 11.8 for adolescents, and 12.1 for adults. In all 3 age groups, TCS increased over 3 years; the increase in TCS from 2003-2005 for children was 1.25 (95% CI 1.16-1.34), for adolescents 0.77 (0.62-0.93), and for adults 1.20 (1.08-1.31) (all P<0.001 for trend over time). At the site level, there were no significant differences in mean TCS based on FEV1 quartile. Mean TCS was higher in the highest BMI z-score quartile. Across all 3 versions of the CFQ-R, mean TCS was lower at sites in the highest quartiles (lowest burden) for CFQ-R treatment burden scores.

CONCLUSION

Treatment complexity was highest among adults with CF, although over 3 years, we observed a significant increase in treatment complexity in all age groups. Such increases in treatment complexity pose a challenge to patient self-management and adherence. Future research is needed to understand the associations between treatment complexity and subsequent health outcomes to reduce treatment burden and improve disease management.

Risk factors for onset of persistent respiratory symptoms in children with cystic fibrosis

OBJECTIVES

To characterize the onset of persistent signs and symptoms of cystic fibrosis (CF) lung disease and identify characteristics that predict onset.

STUDY DESIGN

Patients in the Epidemiologic Study of CF who were <4 years of age at enrollment and had ≥2 years of follow-up were included. We defined persistence as a sign or symptom that was present during two consecutive encounters separated by 60-365 days, and persistent clubbing as ≥50% of encounters with clubbing within 365 days. Predictors were assessed in a Cox proportional hazards model for age at first occurrence of each symptom.

RESULTS

Each sign or symptom met the criterion of persistence in a substantial proportion of patients during a follow-up period of 7 ± 3 years (mean ± SD; range 2-12). Risk factors that predicted earlier onset of signs and symptoms included pancreatic enzyme use, Pseudomonas aeruginosa infection, and prior diagnosis of asthma. Other risk factors had variable effects on signs and symptoms.

CONCLUSIONS

Signs and symptoms of lung disease begin early in CF. Risk factors previously reported for lower forced expiratory volume in 1 sec are also associated with earlier onset of persistent signs and symptoms of CF lung disease, but their impact varies.

Lung function distinguishes preschool children with CF from healthy controls in a multi-center setting

RATIONALE

Conducting clinical trials in cystic fibrosis (CF) preschoolers has been limited by lack of sensitive lung function measures performed across sites.

OBJECTIVES

(1) Assess feasibility and short-term reproducibility of spirometry, forced oscillometry (FO), and inductance plethysmography (IP) in a multi-center preschool population; (2) compare ability of each technique to differentiate lung function of CF preschoolers and controls; (3) evaluate longitudinal changes in lung function; (4) estimate sample sizes for future trials.

METHODS

A longitudinal, multi-center study of CF preschoolers was conducted utilizing standardized equipment, rigorous site training, and centralized lung function data review. CF subjects participated in up to four study visits 6 months apart, plus a 2-week reproducibility visit. Controls had one study visit.

RESULTS

Ninety-three CF subjects and 87 controls participated. Acceptability rates were lowest for spirometry (55%) and highest for IP (77%). Spirometry success increased with age and having a prior acceptable measurement. FEV(1) , FEV(0.5) , and FEF(25-75) were lower for CF subjects than for controls; spirometric z-scores declined with age. IP measures of thoracoabdominal asynchrony were greater for CF subjects than for controls. FO indices did not distinguish CF from controls. FEV(1) and FEV(0.5) are able to detect the smallest treatment effect for a given sample size.

CONCLUSIONS

Spirometry appears more sensitive than IP or FO for detecting lung disease in CF preschoolers; spirometric indices decline with age. Future trials using spirometry should include a run-in period for training and require acceptable data prior to enrollment. However, near-normal spirometric measurements in CF preschoolers may lead to difficulty detecting a treatment effect.

Analysis of the associations between lung function and clinical features in preschool children with cystic fibrosis

OBJECTIVE

To analyze cross-sectional and longitudinal associations between lung function measures and clinical features in a cohort of preschool children with cystic fibrosis (CF).

METHODS

Longitudinal eight-center observational study of children with CF aged 36-60 months at enrollment, who underwent semiannual pulmonary function tests (PFTs) for up to 2 years consisting of spirometry (all 8 sites), forced oscillometry (FO, 5 sites), and measures of thoracoabdominal asynchrony using respiratory inductive plethysmography (IP, 5 sites).

RESULTS

Ninety-three subjects were enrolled; 181 acceptable spirometry measurements from 71 subjects, 128 FO from 47 subjects, and 142 IP from 50 subjects were available for analysis. Cross sectional analyses did not detect an association between any PFT parameter at enrollment and Pseudomonas aeruginosa (Pa) status, CF gene mutation class, Wisconsin cough score, Shwachman score, environmental tobacco smoke exposure, family history of asthma, or nutritional indices. In longitudinal analyses, Pa infection within 6 months preceding enrollment was associated with a significantly greater rate of decline in z-scores for forced expiratory flow between 25 and 75% of forced vital capacity (FEF(25-75) ) (-1.3 vs. -0.4 Z scores/year, P = 0.024) and greater thoracoabdominal asynchrony measured by IP (mean phase angle difference 4.6°, P = 0.004). No other significant longitudinal associations were observed.

CONCLUSIONS

Prior Pa infection is associated with a greater rate of decline in FEF(25-75) z-score and mild thoracoabdominal asynchrony in preschool children with CF. In this multicenter US study, significant associations between other lung function measures and clinical features were not detected.

Multiple antibiotic-resistant Pseudomonas aeruginosa and lung function decline in patients with cystic fibrosis

BACKGROUND

The goal of this study was to determine the association of multiple antibiotic-resistant Pseudomonas aeruginosa (MARPA) acquisition with lung function decline in patients with cystic fibrosis (CF).

METHODS

Using data from Epidemiologic Study of Cystic Fibrosis (ESCF), we identified patients with spirometry data and MARPA, defined as PA (1) resistant to gentamicin and either tobramycin or amikacin, and (2) resistant to ≥1 antipseudomonal beta lactam. MARPA had to be detected in a respiratory culture after ≥2 years of PA-positive but MARPA-negative respiratory cultures. Multivariable piecewise linear regression was performed to model the annual rate of decline in forced expiratory volume in 1 second (FEV(1)) % predicted 2 calendar years before and after the index year of MARPA detection, adjusting for patient characteristics and CF therapies.

RESULTS

In total, 4349 patients with chronic PA and adequate PFT data were identified; 1111 subsequently developed MARPA, while 3238 patients were PA positive but MARPA negative. Compared with patients who did not acquire MARPA, MARPA-positive patients had lower FEV(1) and received more oral (p<0.013) and inhaled (p<0.001) antibiotic therapy. Mean FEV(1) decline did not change significantly after MARPA detection (-2.22% predicted/year before detection and -2.43 after, p=0.45). There was no relationship between persistent infection or FEV(1) quartile and FEV(1) decline.

CONCLUSIONS

Newly detected MARPA was not associated with a significant change in the rate of FEV(1) decline. These results suggest that MARPA is more likely to be a marker of more severe disease and more intensive therapy, and less likely to be contributing independently to more rapid lung function decline.

Clinical outcomes in infants with cystic fibrosis transmembrane conductance regulator (CFTR) related metabolic syndrome

An unavoidable outcome of cystic fibrosis newborn screening (CF NBS) programs is the detection of infants with an indeterminate diagnosis. The United States CF Foundation recently proposed the term cystic fibrosis transmembrane conductance regulator related metabolic syndrome (CRMS) to describe infants with elevated immunoreactive trypsinogen (IRT) on NBS who do not meet diagnostic criteria for CF. The objective of this study was to describe the clinical outcomes of infants with CRMS identified through an IRT/DNA algorithm. We reviewed the records of all infants with CRMS diagnosed at our CF Center from 2002 to 2010. We identified 12 infants, and compared them to 27 infants diagnosed with CF by NBS. Compared to CF patients, CRMS patients were more likely to be pancreatic sufficient as assessed by fecal elastase measurement (100% vs. 8%, P < 0.01). Their weight for age percentile was normal from birth. A positive oropharyngeal (OP) culture for Pseudomonas aeruginosa (Pa) was found in 25% of CRMS patients. One patient with the F508del/R117H/7T genotype was reassigned the diagnosis of CF after he had a positive OP culture for Pa, and his follow up sweat Cl at 1 year of life was 73 mmol/L. CF patients were more likely to receive oral antibiotics and be hospitalized for pulmonary symptoms. Our results indicate that CRMS patients can develop signs of CF disease, but have a milder clinical course than CF infants. Close initial monitoring of these patients is warranted. Pediatr. Pulmonol. 2011; 46:1079-1084. © 2011 Wiley Periodicals, Inc.

Baseline characteristics and factors associated with nutritional and pulmonary status at enrollment in the cystic fibrosis EPIC observational cohort

SUMMARY BACKGROUND

The EPIC Observational Study is an ongoing prospective cohort study investigating risk factors for and clinical outcomes associated with early Pseudomonas aeruginosa (Pa) acquisition in young children with cystic fibrosis (CF).

OBJECTIVES AND HYPOTHESIS

To describe the baseline characteristics of the cohort and evaluate associations between potential risk factors and nutritional and respiratory characteristics at enrollment. We hypothesized that distinct demographic and environmental risk factors could be identified for poorer nutritional status and lung function at enrollment.

METHODS

During 2004-2006, 1,700 children with CF were enrolled at 59 US CF centers. Children <or=12 years were eligible if they had no prior Pa infection (Pa-Never) or, if prior isolation of Pa from respiratory cultures, at least a 2-year history of Pa negative cultures (Pa-Past).

RESULTS

One thousand one hundred seventeen participants (65.7%) were Pa-Never and 583 (34.3%) Pa-Past. Pa-never patients had a lower proportion of CFTR genotypes with both mutations in functional classes I, II, or III), higher lung function and less respiratory symptoms. Diagnosis after newborn or prenatal screening was associated with significantly higher mean weight, height, and FEV(1) at enrollment, while maternal smoking during pregnancy appeared to worsen these parameters.

CONCLUSIONS

Children in this cohort with a remote history of Pa infection had a higher proportion of CFTR genotypes associated with severely reduced CFTR function as well as lower lung function and more respiratory symptoms than those without prior Pa infection. These observed differences in respiratory indices may reflect the impact of prior Pa airway infection and/or of CFTR genotype or other genetic factors predisposing both to earlier Pa acquisition and more severe lung disease. Key characteristics associated with nutritional and pulmonary status at enrollment included diagnosis after prenatal or neonatal screening (protective) and in utero cigarette exposure (harmful).

Diagnosis of cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene that results in abnormal viscous mucoid secretions in multiple organs and whose main clinical features are pancreatic insufficiency and chronic endobronchial infection. Although it was initially defined and diagnosed based on clinical features and sweat chloride measurement, an in vivo method of assessing CFTR function, the discovery of the CFTR gene in 1989 revealed a broad spectrum of CF phenotypes associated with specific CFTR gene mutations. In this article, we will review the indications for sweat testing, alternative techniques to diagnose CF, and the approach to patients with an ambiguous or indeterminate diagnosis of CF.

Cystic fibrosis: evolution from a fatal disease of infancy with a clear phenotype to a chronic disease of adulthood with diverse manifestations

Cystic fibrosis (CF) is the most common life-threatening genetic condition in the Caucasian population. Since the complete pathologic description of the disease in 1938, tremendous progress has been made in identifying its genetic basis, the pathophysiology of CF lung disease, and the development of new therapies. This issue of CRAI will review several areas of progress in our understanding and treatment of CF.

The impact of incident methicillin resistant Staphylococcus aureus detection on pulmonary function in cystic fibrosis

The incidence of methicillin resistant Staphylococcus aureus (MRSA) infection is increasing in cystic fibrosis (CF), but the impact of MRSA detection on clinical outcomes is unclear. Our objective was to determine whether incident detection of MRSA is associated with a change in pulmonary function over time in CF patients. We analyzed data from the Epidemiologic Study of Cystic Fibrosis (ESCF), a prospective observational study of CF patients in North America. Multivariable piecewise linear regression was used to model the impact of incident detection of MRSA on pulmonary function over time, measured by percent predicted forced expiratory volume in one second (FEV(1)% predicted), adjusting for potential confounders. There were 5,090 patients >or=6 years old who were MRSA negative for at least 2 calendar years. Five hundred ninety-three (12%) of these patients acquired MRSA during the years 2001-2003, with detection rates of MRSA during those years rising from 4.4% to 6.9%. MRSA positive patients had a lower FEV(1)% predicted and received more antibiotic and other therapies than patients who remained MRSA negative. After adjusting for antibiotic therapy and other potential confounders, MRSA positive patients also had a higher rate of decline in FEV(1)% predicted both before and after the incident culture, although the rate of FEV(1)% predicted decline did not change significantly after MRSA detection. In conclusion, although MRSA in CF was a marker for more aggressive therapy and may reflect increased disease severity, incident MRSA detection was not associated with a changing rate of FEV(1)% predicted decline.

Trends in the clinical characteristics of the U.S. cystic fibrosis patient population from 1995 to 2005

RATIONALE

Respiratory signs and symptoms (cough, sputum production, or crackles) are considered bellwethers of underlying cystic fibrosis (CF) lung disease. If respiratory signs and symptoms predict future lung function loss, then improvements in population lung function over the past decade should have been paralleled by a decrease in the prevalence of these variables in the same population. Additionally, changes in these variables over the past decade may provide insight into the improving health of the CF population.

METHODS

Cross-sectional data from the Epidemiologic Study of Cystic Fibrosis for each year between 1995 and 2005 were analyzed to characterize changes in pulmonary function and respiratory signs and symptoms over time. Patients were separated into five age groups: <6, 6-12, 13-17, 18-24, and >or=25 years.

RESULTS

Serial cross-sectional analyses of an average of 13,381 patients per year indicated that mean pulmonary function for the CF population improved and the percent of patients reporting cough or sputum production or having crackles or wheeze at their clinic visit decreased over the study period. Observed changes in pulmonary function were not consistently mirrored by changes in symptoms, which differed as a function of the variable studied and the age group.

CONCLUSIONS

Reductions in respiratory signs and symptoms have paralleled improvements in pulmonary function. Both the absolute and relative magnitude of changes in prevalence for cough, sputum production, crackles, and wheeze differed among age groups and among variables. These results suggest the possibility that differences in respiratory signs and symptoms may arise from different underlying pathologies and may be influenced differently by therapeutic interventions.

Assessment and monitoring of cystic fibrosis lung disease in infants and young children

Chronic airway infection and inflammation are the hallmarks of cystic fibrosis (CF) lung disease. As these events occur early in life, it is critical to develop techniques for the assessment and monitoring of early-CF lung disease in infants and young children. In the last several years, there have been major advances in the development of imaging technology to assess structural damage in CF lung disease, noninvasive markers of CF airway inflammation and measurement of lung function in infants and young children with CF. In this article, we will review these advances and techniques, and discuss future directions for research and clinical applications.

Presence of methicillin resistant Staphylococcus aureus in respiratory cultures from cystic fibrosis patients is associated with lower lung function

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) infections is increasing in both the general population and cystic fibrosis (CF) patients. We hypothesized that MRSA infection of the conductive airways as seen in CF would be associated with more severe disease than that seen with methicillin sensitive S. aureus (MSSA). To test this hypothesis, we used data from the Epidemiologic Study of Cystic Fibrosis (ESCF), a large observational study of CF patients in North America, to compare CF patients with MRSA in their respiratory tract cultures to those with MSSA. During a 1-year time period from January 1, 2001 to December 31, 2001, data from 20,451 patients were collected by the ESCF, and 1,834 (7.5%) patients had respiratory tract cultures that were positive for S. aureus only. Compared to patients with MSSA only, patients with MRSA only had significantly more airflow obstruction, as measured by forced expiratory volume in 1 sec (FEV1). The mean FEV1 for patients 6-17 years old with MRSA was 80.7% predicted compared to 89.4% in the MSSA group (P<0.001). The likelihood of hospitalization and treatment with oral, inhaled, and intravenous antibiotics were all significantly increased in patients with MRSA compared to those with MSSA. Similar results were seen in patients >or=18 years old. The results of our study highlight the growing clinical impact of MRSA infections in CF patients.

Infant care patterns at epidemiologic study of cystic fibrosis sites that achieve superior childhood lung function

OBJECTIVE

Previous analyses of the Epidemiologic Study of Cystic Fibrosis database revealed that sites with the highest average patient lung function monitor patients and treat with antibiotics more aggressively than those where average lung function is lowest. The aim of this study was to assess whether patterns of care for infants at cystic fibrosis sites with superior average lung function in 6- to 12-year-old children showed any differences from those at the lowest outcome sites.

METHODS

We divided cystic fibrosis sites with > or = 20 patients who were 6 to 12 years of age into quartiles on the basis of median forced expiratory volume in 1 second of that age group in 2003 and compared demographic and clinical characteristics and treatment patterns during the first year of enrollment for patients who were aged 0 to 3 years at those sites in 1994 to 1999. The analysis included 755 infants from 12 upper quartile sites and 743 infants from 12 lower quartile sites.

RESULTS

Upper quartile sites had more infants whose disease was diagnosed by family history or newborn screening, fewer infants with symptoms at diagnosis, higher weight for age at enrollment, more white patients, and more deltaF508 homozygotes. Medical conditions and respiratory tract microbiology differed between sites. Infants at upper quartile sites had more office and sick visits; more respiratory tract cultures; and more frequent use of intravenous antibiotics, oral corticosteroids, mast cell stabilizers, and mucolytics; but they received less chest physiotherapy, inhaled bronchodilators, oral nutritional supplements, and pancreatic enzymes.

CONCLUSIONS

Both enrollment characteristics and infant care patterns are associated with lung function outcomes in later childhood. Our analysis suggests that pulmonary function of older children may be improved through specific interventions during the first 3 years of life.

Changes in lung function measured by spirometry and the forced oscillation technique in cystic fibrosis patients undergoing treatment for respiratory tract exacerbation

Objective measures of lung function are critical for the treatment and study of lung diseases such as cystic fibrosis (CF). Spirometry is the most widely used and accepted method of pulmonary function testing in CF, but not all patients can perform the maneuvers required to obtain valid results from spirometry. The forced oscillation technique (FOT) requires less cooperation than spirometry. The goals of this study were to determine if FOT could detect changes in lung function in CF patients receiving inpatient treatment of respiratory tract exacerbations (RTEs), and to gather preliminary data on the magnitude of these changes and the variability of FOT data in such patients. We performed a retrospective chart review of CF patients admitted to the hospital for RTEs. We identified 14 patients who had both spirometry and FOT performed at the beginning and end of their treatment course. Their mean age was 15.9 years (range, 8-18). The mean forced expiratory volume in 1 sec (FEV1) on admission was 62.57% predicted. FEV1 increased by 27.1 +/- 33.15% (mean +/- SD, P = 0.008). The absolute value of reactance at 5 Hz (X5) decreased by 22.3 +/- 25.1% (P = 0.005), while resistance at 5 Hz decreased by 11.6 +/- 17.3% (P = 0.025). There was a significant relationship between changes in FEV1 and X5 (P = 0.003, r2 = 0.54). Our study demonstrates that FOT can detect significant changes in lung function in CF patients receiving treatment for RTEs. We speculate that FOT can serve as an alternative method to measure lung function in CF patients unable to perform spirometry, such as young children.

Use of complementary and alternative medicine by parents of children with HIV infection and asthma and well children

OBJECTIVE

Although the use of complementary and alternative medicine (CAM) in children is increasing, little is known about its use in children with human immunodeficiency virus (HIV) infection. This study investigated the use of CAM by parents of children with HIV infection (H), children with asthma (A), and well children (W). Our hypothesis was that parents of the H group are more likely to use CAM than parents of the W or A group because of the nature and severity of the illness.

MATERIALS AND METHODS

Parents of 152 subjects [H (n = 46), A (n = 53), and W (n = 53)] were interviewed on the use of CAM for their children, types of CAM, reasons for use/nonuse, methods of payment, and perceived benefits for their children.

RESULTS

Compared with parents of the W and A groups, parents of the H group were less likely to be employed, were less likely to have private insurance, were less likely to have a high school or college education, and were more likely to be black. Interestingly, 38% of the W parents used CAM in their children compared with 22% in the H group and 25% in the A group. More than 80% of all three groups paid out of pocket for their use of CAM in their children. Within these groups, H parents were more likely to want CAM as part of their child's medical care (H = 91% vs W = 75% and A = 67%, P = 0.02) and were more likely to believe that CAM was expensive (H = 78% vs W = 57% and A = 60%, P < 0.01).

CONCLUSIONS

Our study revealed a relatively high rate of CAM usage by parents of all three study groups. Although parents of children with HIV infection were more likely to want CAM as part of their children's medical care, their rate of CAM usage was not higher than that in well children. This may be related to their socioeconomic factors. A larger and more diverse study population may provide more information on factors contributing to CAM usage in chronically ill and well children.

Use of modulators of airways inflammation in patients with CF

One of the hallmarks of cystic fibrosis (CF) lung disease is the presence of intense, neutrophil-dominated airway inflammation, and many researchers have focused on developing therapies to reduce inflammation in CF lung disease. Systemic corticosteroids can delay progression of lung disease, but at the cost of unacceptable side effects. Inhaled corticosteroids are widely used, but their efficacy has yet to be demonstrated in a controlled fashion. Ibuprofen has also been shown to delay disease progression, but its use has been limited by the need to obtain individual pharmacokinetics and concern about side effects. Other treatments with potential anti-inflammatory effects include pentoxifylline, leukotriene antagonists, docosahexaenoic acid, and azithromycin. Few, if any, large clinical studies of these therapies have been published, but several are presently underway. Because neutrophil elastase appears to be a key mediator of tissue damage in CF lung disease, anti-elastase compounds have also been studied, including alpha-1-protease inhibitor, secretory leukocyte protease inhibitor, and small molecule inhibitors. There have been no large-scale controlled trials of these therapies in CF. More recently, investigators have focused on cytokine modulation, using either interleukin-10 or interferon gamma. Some complementary and alternative medicine therapies may also have anti-inflammatory effects, although their clinical value has yet to be demonstrated in a rigorously-controlled fashion. In summary, numerous anti-inflammatory therapies have been applied to CF lung disease, but more large, well-controlled studies will need to be performed to determine their true clinical usefulness.

Pulmonary function in technology-dependent children 2 years and older with bronchopulmonary dysplasia

Somatic and pulmonary growth coincide with resolution of hypoxemia by 2 years of age in most children with bronchopulmonary dysplasia (BPD). However, a distinct subgroup of children with BPD continue to require mechanical ventilation and/or supplemental oxygen beyond 2 years of age. This study tested the hypothesis that indices of pulmonary function would be significantly worse in children with BPD 2 years and older who remained technology-dependent secondary to hypoxemia, compared to those of age-matched children with BPD who were normoxemic. We measured pulmonary mechanics in 21 oxygen- or ventilator-dependent children with BPD 2 years and older (BPDO2 group; mean age+/-SD, 30.2+/-6.5 months) and in 19 children with BPD who had been weaned off mechanical ventilation and supplemental oxygen for at least 6 months (control group; mean age, 30.1+/-5.5 months). Respiratory rate and tidal volume were measured after sedation with chloral hydrate, and dynamic compliance and expiratory conductance were calculated using the esophageal catheter technique. Maximal flow at FRC (V'(maxFRC)) and ratio of forced-to-tidal flows at midtidal volume were obtained by the rapid thoracic compression technique. FRC was determined by nitrogen washout. There were no statistically significant differences in most measured indices of pulmonary mechanics between the BPDO2 and control groups. However, V'(maxFRC)/FRC was higher in controls compared to subjects in the BPDO2 group (0.81+/-0.40 sec(-1) vs. 0.34+/-0.21 sec(-1), P<0.003). We conclude that most indices of pulmonary function in children with BPD 2 years and older do not reflect the need for mechanical ventilation or supplemental oxygen. We speculate that measurements of lung elastic recoil and tests of distribution of ventilation and pulmonary perfusion may be more sensitive in differentiating normoxemic and hypoxemic children with BPD 2 years and older.

[Dynamics of growth and total tanshinones accumulation in crown gall cultures of salvia miltiorrhiza]

AIM

To determine the dynamics of growth and total tanshinones accumulation in crown gall cultures of Salvia miltiorrhiza in MS and 67-V liquid media.

METHODS

Fresh, dry weight and total tanshinones yields in the cultures and in the medium were determined every 5 days in crown gall suspension cultures.

RESULTS

In MS medium, the logarithmic growth phase of crown gall cultures in S. miltiorrhiza was from the 5th to 30th days, and the stationary growth phase was from the 30th to 35th days. From the 25th to 30th days, physiological activity of crown gall cultures was higher and their growth was better. However, in 67-V medium, the logarithmic growth phase of crown gall cultures was from the 10th to 25th days, and the stationary growth phase was from the 25th to 35th days. Total tanshinones were largely accumulated in the cultures and in the medium after 25 days. The total tanshinones yield (60 mg.L-1) was reached at the 35th day.

CONCLUSION

Knowing the regularity of the growth and total tanshinones accumulation in crown gall cultures of S. miltiorrhiza will be helpful to take proper regulative measures in order to obtain the maximum total tanshinones yield.

Role of protein tyrosine kinases and phosphatases in isotype switching: crosslinking CD45 to CD40 inhibits IgE isotype switching in human B cells

Protein tyrosine kinases and protein tyrosine phosphatases play an important role in the transduction of signals via antigen receptors in T and B cells, and in CD40-dependent B-cell activation. To examine the role of tyrosine kinases and phosphatases in B-cell isotype switching, we examined the effects of the engagement of the transmembrane phosphatase CD45 on the synthesis of IgE induced by IL-4 and anti-CD40 monoclonal antibody (mAb). Crosslinking CD45 to CD40 using biotinylated mAbs and avidin strongly inhibited CD40-mediated IgE synthesis in IL-4-treated human B cells. CD40/CD45 crosslinking did not affect epsilon germline transcription in B cells stimulated with IL-4, but strongly inhibited induction of S mu/S epsilon switch recombination as detected by a nested primer polymerase chain reaction assay. The B-cell src-type tyrosine kinase lyn, which is activated following CD40 engagement, is a potential target for the effects of CD45 observed in our experiments, because CD45/CD40 crosslinking resulted in the inhibition of CD40-mediated lyn phosphorylation and activation. These results suggest an important role for protein tyrosine kinases and phosphatases in CD40-mediated induction of isotype switching to IgE.

Protein tyrosine kinase activation and protein kinase C translocation are functional components of CD40 signal transduction in resting human B cells

CD40 is a 47kD glycoprotein expressed on all B cells that plays an important role in B cell development and activation. Previous investigations have focused on signal transduction events in activated B cells and B cell lines, and little information is available regarding CD40 signal transduction in resting, normal B cells. Because CD40 plays a critical role in the regulation and activation of resting B cells, we studied the signaling mechanisms involved in functional responses to CD40 ligation in these cells. Treatment of dense tonsil B cells with either protein tyrosine kinase (PTK) or protein kinase C (PKC) inhibitors, but not with an inhibitor of cyclic nucleotide dependent kinases, resulted in abrogation of CD40-mediated cell adhesion, suggesting a role for both PTK and PKC in CD40-mediated B cell adhesion. Direct evidence for CD40-mediated PTK activation was demonstrated by increased tyrosine phosphorylation as detected by anti-phosphotyrosine Western blots of cell lysates prepared from dense resting tonsil B cells stimulated with biotinylated anti-CD40 monoclonal antibody plus avidin. CD40 engagement also resulted in PKC activation, as detected by translocation of cytosolic PKC activity to the membrane-bound compartment. CD40-mediated PKC translocation was dependent on PTK activation, whereas PTK activity induced by CD40 ligation was independent of PKC activity, suggesting that PTK activation precedes PKC activation in resting B cells stimulated with anti-CD40 mAb. The results of our experiments identify PTK and PKC activation as components of CD40 signal transduction in normal, resting B cells and establish a functional role for these events.

Role of protein tyrosine kinases in CD40/interleukin-4-mediated isotype switching to IgE

The B-cell antigen CD40 transduces signals, which synergize with interleukin (IL)-4 to induce IgE synthesis in human B cells. IL-4 induces epsilon germline transcription but not mature epsilon transcripts or IgE protein synthesis in B cells. Addition of anti-CD40 monoclonal antibody to IL-4-treated B cells results in deletional S mu--> S epsilon switch recombination, expression of mature epsilon transcripts, and IgE synthesis and secretion. Because both IL-4 and anti-CD40 induce protein tyrosine phosphorylation in B cells, we investigated the role of protein tyrosine kinase in IL-4/CD40-mediated IgE synthesis. The protein tyrosine kinase inhibitors genistein and herbimycin A, but not the protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) or the protein kinase A inhibitor N-2-guanidinoethyl-5-isoquinolinesulfonamide, inhibited IgE synthesis in B cells stimulated with IL-4 and CD40. Genestein and herbimycin, but not H7, inhibited IL-4-driven epsilon germline transcription in B cells. Both genestein and herbimycin, but not H7, inhibited CD40-mediated IgE synthesis in B cells pretreated for 4 days with IL-4 to allow optimal expression of epsilon germline transcripts. Inhibition of IgE synthesis in these cultures was accompanied by inhibition of S mu--> S epsilon deletional switch recombination as assayed by nested polymerase chain reactions. These results suggest that activation of protein tyrosine kinase plays an important role in both the IL-4 and the CD40 signalling pathways that lead to IgE isotype switching in B cells.

Signal transduction via CD40 involves activation of lyn kinase and phosphatidylinositol-3-kinase, and phosphorylation of phospholipase C gamma 2

CD40 is a 50-kD glycoprotein that plays an important role in B cell survival, memory, and immunoglobulin isotype switch. Engagement of the CD40 antigen by monoclonal antibodies (mAbs) results in increased protein tyrosine kinase (PTK) activity, which plays an important role in mediating the biologic effects of CD40. We demonstrate, using an in situ phosphorylation technique, that CD40 cross-linking by the anti-CD40 mAb 626.1 resulted within 1 min in increased phosphorylation of the src type kinase, lyn, in Daudi B cell lines and remained sustained for up to 20 min. The activity of lyn kinase, as measured by immune complex kinase assay, was also increased after CD40 engagement, with similar kinetics. In contrast, the phosphorylation and activity of fyn, fgr, and lck kinases demonstrated minimal changes following stimulation of Daudi cells with mAb 626.1 over this same time period. CD40 engagement also resulted in phosphorylation of phospholipase C gamma 2 of phosphatidylinositol (PLC gamma 2) and phosphatidylinositol (PI)-3-kinase. Phosphorylation of PI-3-kinase was shown to be associated with an increase in its enzymatic activity. These results suggest that lyn plays an important role in CD40-mediated PTK activation and identify PLC gamma 2 and PI-3-kinase targets for CD40-mediated phosphorylation, suggesting a role for these two enzymes in CD40 signal transduction.

Anatomic distribution of autonomic neural tissue in the developing dog heart: II. Nonadrenergic noncholinergic innervation by calcitonin gene-related peptide-immunoreactive tissue

We used immunocytochemical localization of calcitonin gene-related peptide (CGRP) to trace the ontogenesis and anatomic distribution of this component of nonadrenergic noncholinergic (NANC) innervation in fetal, neonatal, and mature canine hearts and autonomic ganglia which control cardiac function. Rare varicose CGRP-immunoreactive nerve processes were present in the heart during late gestation. Abundant CGRP-immunoreactive neural tissue in the neonate suggested a burst of NANC innervation around birth. Neonatal, 1-, and 2-month-old animals all had many varicose individual nerve processes in addition to processes within bundles; however, the density of all CGRP-immunoreactive tissue appeared to decrease during this stage of development. Similarly, there were relatively more varicose stained nerve processes in the epicardial ganglia and numerous CGRP-immunoreactive cells and smooth nerve processes in the stellate ganglia of the neonate, as compared with older animals. In the mature animal CGRP-immunoreactive neural tissue in the heart was more sparse and largely confined to heterogeneous nerve bundles in the epicardium. The extramural coronary arteries were virtually the only site of innervation by individual nerve processes; CGRP-immunoreactive neural tissue was not found adjacent to working cardiac muscle fibers. At all developmental stages, the area of the sinoatrial node was the primary focus of CGRP innervation, although the atrioventricular nodal region was also preferentially innervated. In general, the atria contained more CGRP-immunoreactive tissue than the ventricles, which were only sparsely innervated. The perinatal peak in density of CGRP-immunoreactive neural tissue with subsequent decline to reach the adult pattern suggests a developmental role for NANC innervation in the dog heart.

Nonadrenergic noncholinergic innervation. Anatomic distribution of calcitonin gene-related peptide-immunoreactive tissue in the dog heart

Calcitonin gene-related peptide (CGRP) has inotropic and chronotropic effects in rat and guinea pig hearts. It also may mediate nonadrenergic noncholinergic regulation of canine cardiac electrophysiology. In this study, immunohistochemistry was used to determine the anatomic distribution of CGRP in mature dog heart and autonomic ganglia controlling cardiac function. The stellate ganglia had scattered CGRP-immunoreactive cells and nerve processes; intracardiac ganglia contained stained nerve processes but no CGRP-immunoreactive cells. Although the extramural coronary arteries were modestly innervated by varicose individual nerve processes, the great majority of CGRP-immunoreactive neural tissue in the heart existed adjacent to the sinoatrial node where varicose nerve processes coursed in numerous large nerve bundles. Each bundle contained only a few stained processes, however, indicating that CGRP-immunoreactive nerve processes were accompanying another type of autonomic tissue. Double staining and immunoultrastructure confirmed that the nerve bundles were heterogeneous. Similar nerve bundles were fewer in the left atrium, the region of the atrioventricular node, atrioventricular bundle, and the ventricles. In contrast to the distribution of sympathetic neural tissue, CGRP-immunoreactive nerve processes virtually were nonexistent among muscle fibers. We conclude that 1) CGRP-immunoreactive neural tissue likely affects sympathetic and parasympathetic ganglia that control cardiac function, 2) the preponderance of this nonadrenergic noncholinergic tissue near regions of specialized muscle (especially the sinoatrial node) suggests an efferent function in the canine heart, and 3) the presence of varicosities along CGRP-immunoreactive nerve processes within heterogeneous nerve bundles may indicate that direct axo-axonal contact is the mechanism by which these nonadrenergic noncholinergic nerve processes modulated other autonomic neural tissue.

Anatomic distribution of autonomic neural tissue in the developing dog heart: I. Sympathetic innervation

We used immunocytochemical localization of tyrosine hydroxylase to trace the ontogenesis and anatomic distribution of sympathetic innervation in fetal, neonatal, and mature canine hearts. Sparse tyrosine hydroxylase-positive neural tissue first appeared in the atrium, including sinoatrial and atrioventricular nodes, and the ventricular epicardium at midgestation and progressively increased in extent to reach the adult pattern by 2 months following birth. Sympathetic innervation of the atrioventricular bundle occurred relatively later, with no nerve processes in the neonate but a mature pattern by 2 months. At each developmental stage the atria contained more tyrosine hydroxylase-positive neural tissue than the ventricles. Thus, sympathetic nerve processes appear in the developing canine heart earlier than was previously recognized. The time course of sympathetic innervation as defined by this anatomic study is in accord with electrophysiologic studies indicating progressive neonatal development of sympathetic effect which achieves maturity by 2 months of age.