Dataset Information

Alveolarization continues during childhood and adolescence: new evidence from helium-3 magnetic resonance.

ABSTRACT:

Rationale

The current hypothesis that human pulmonary alveolarization is complete by 3 years is contradicted by new evidence of alveolarization throughout adolescence in mammals.

Objectives

We reexamined the current hypothesis using helium-3 ((3)He) magnetic resonance (MR) to assess alveolar size noninvasively between 7 and 21 years, during which lung volume nearly quadruples. If new alveolarization does not occur, alveolar size should increase to the same extent.

Methods

Lung volumes were measured by spirometry and plethysmography in 109 healthy subjects aged 7-21 years. Using (3)HeMR we determined two independent measures of peripheral airspace dimensions: apparent diffusion coefficient (ADC) of (3)He at FRC (n = 109), and average diffusion distance of helium (X(rms)) by q-space analysis (n = 46). We compared the change in these parameters with lung growth against a model of lung expansion with no new alveolarization.

Measurements and main results

ADC increased by 0.19% for every 1% increment in FRC (95% confidence interval [CI], 0.13-0.25), whereas the expected change in the absence of neoalveolarization is 0.41% (95% CI, 0.31-0.52). Similarly, increase of (X(rms)) with FRC was significantly less than the predicted increase in the absence of neoalveolarization. The number of alveoli is estimated to increase 1.94-fold (95% CI, 1.64-2.30) across the age range studied.

Conclusions

Our observations are best explained by postulating that the lungs grow partly by neoalveolarization throughout childhood and adolescence. This has important implications: developing lungs have the potential to recover from early life insults and respond to emerging alveolar therapies. Conversely, drugs, diseases, or environmental exposures could adversely affect alveolarization throughout childhood.

SUBMITTER: Narayanan M

PROVIDER: S-EPMC3410735 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Alveolarization continues during childhood and adolescence: new evidence from helium-3 magnetic resonance.

Narayanan Manjith M Owers-Bradley John J Beardsmore Caroline S CS Mada Marius M Ball Iain I Garipov Ruslan R Panesar Kuldeep S KS Kuehni Claudia E CE Spycher Ben D BD Williams Sian E SE Silverman Michael M

American journal of respiratory and critical care medicine 20111027 2

<h4>Rationale</h4>The current hypothesis that human pulmonary alveolarization is complete by 3 years is contradicted by new evidence of alveolarization throughout adolescence in mammals.<h4>Objectives</h4>We reexamined the current hypothesis using helium-3 ((3)He) magnetic resonance (MR) to assess alveolar size noninvasively between 7 and 21 years, during which lung volume nearly quadruples. If new alveolarization does not occur, alveolar size should increase to the same extent.<h4>Methods</h4>L ...[more]

PMID: 22071328

Similar Datasets

Project description:BackgroundAs more adults undergo surgical fixation of clavicle fractures with improved outcomes, interest is renewed in managing clavicle fractures in adolescents. The medial clavicular physis does not fuse until 23 to 25 years of age, but studies report minimal clavicular growth during adolescence-studies that employed cross-sectional methodologies, which cannot not capture growth in patients over time. The assumption that clavicle length at each stage is uniform, as is the final overall length, may not be accurate if the age groups studied comprise various ethnicities, socioeconomic status, or height.Questions/purposesWe sought to quantify longitudinal clavicular growth on serial radiographs in adolescents and young adults. Our hypothesis was that substantial clavicular growth would be seen beyond the age of 12 years.MethodsWe conducted a longitudinal case series of non-syndromic patients in a single orthopedic clinic and analyzed serial radiographic images of the clavicles. For ethical reasons, only patients with non-neuromuscular scoliosis and kyphosis (in whom the existing standard of care includes serial thoracic radiographs) were considered for inclusion. Patients ages 10 to 25 years old were included in the study if three or more serial thoracic radiographs over a minimum 5 years were available that captured the entire length of at least one non-rotated clavicle. Three types of radiographs were included for analysis: digital low-dose-radiation stereoradiographic (EOS Imaging, Paris, France), non-EOS digital, and non-EOS printed. The overall longitudinal growth, yearly growth, and the yearly growth percentage were calculated for each clavicle.ResultsFifty-seven patients (22 male and 35 female) met the inclusion criteria. In male patients, at ages 12 to 15 years, the clavicular growth was 4.9 mm/year, or 4%/year; at ages 16 to 19 years, growth was 3.2 mm/year, or 2.4%/year; and at ages 20 to 25 years, growth was 1.7 mm/year, or 1.1%/year. In female patients, at ages 12 to 15 years, growth was 4.7 mm/year, or 4%/year; at 16 to 19 years, growth was 2.2 mm/year, or 1.7%/year; and at ages 20 to 25 years, growth was 0.2 mm/year or 0.1%/year. We could not detect the age of terminal growth in either sex because growth was ongoing in most patients in the oldest group.ConclusionWe found substantial clavicular growth potential after age 18 years, when growth is thought to be nearly finished, as well as remodeling potential even up to age 25 years. Further research is needed, but our findings suggest that strategies for managing clavicle fracture in adults may not be applied universally to adolescents and young adults.

Dataset Information

Alveolarization continues during childhood and adolescence: new evidence from helium-3 magnetic resonance.

Rationale

Objectives

Methods

Measurements and main results

Conclusions

Publications

Alveolarization continues during childhood and adolescence: new evidence from helium-3 magnetic resonance.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets