123I-MIBG radioaerosol lung clearance in COPD patients with fixed and partially reversible obstruction to evaluate the functional status of pulmonary adrenergic innervation.
In order to test the hypothesis that a greater sympathetic activity underlies partial reversibility of the bronchial obstruction in selected patients with chronic obstructive pulmonary disease (COPD), we assessed the pulmonary clearance of inhaled I-meta-iodobenzylguanidine ( I-MIBG) radioaerosol in 10 patients with fixed and nine with reversible obstruction. The clearance of inhaled I-MIBG is known to be inversely related to I-MIBG uptake by adrenergic terminals. Groups were matched for age and judged free from confounding comorbidity. The penetration index did not distinguish between the groups (fixed obstruction, 97.39+/-14.59%; reversible obstruction, 89.09+/-19.95%; P=0.659); this excludes the possibility that the inequality of tracer penetration could affect I-MIBG clearance. The I-MIBG clearance was 140.92+/-7.67 min in patients with fixed obstruction and 151.08+/-31.54 min in patients with reversible obstruction ( P=0.604). In conclusion, COPD patients with fixed and reversible obstruction show comparable binding of the tracer to adrenergic pulmonary receptors. Thus, a greater receptor responsiveness or post-receptor mechanism probably underlies the partial reversibility of bronchial obstruction.
Antonelli Incalzi
R
R
Departments of Geriatrics, Nuclear Medicine and Respiratory Physiology, Catholic University, Rome, Italy.
Giordano
A
A
Fuso
L
L
Basso
S
S
Calcagni
M L
ML
Reale
F
F
Boniello
V
V
Pistelli
R
R
D019797:3-Iodobenzylguanidine / Q000008:administration & dosage; D000280:Administration, Inhalation; D000336:Aerosols; D000368:Aged; D000402:Airway Obstruction / Q000000981:diagnostic imaging; D005260:Female; D005540:Forced Expiratory Flow Rates; D006207:Half-Life; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000294:innervation*; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D012129:Respiratory Function Tests; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging* / Q000502:physiology*; D014797:Vital Capacity
D000336:Aerosols; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine