Neuroadrenergic denervation of the lung in type I diabetes mellitus complicated by autonomic neuropathy.
OBJECTIVE
To verify whether autonomic neuropathy (AN) complicating type I, insulin-dependent diabetes mellitus affected neuroadrenergic bronchopulmonary innervation.


METHODS
Twenty nonsmoking diabetic patients without respiratory diseases were studied: 11 patients with AN (group AN) and 9 patients without AN (control; group C) diagnosed by standardized criteria.


METHODS
Patients underwent respiratory function tests and ventilatory scintigraphies with (123)I-metaiodobenzylguanidine (MIBG) and with (99m)Tc-diethylenetriaminepenta-acetic acid (DTPA) to assess both bronchopulmonary neuroadrenergic innervation and also permeability of the alveolar-capillary barrier to water-soluble tracers. Rates of pulmonary clearance of the two tracers were computed, and correlates were identified by nonparametric statistics.


METHODS
University hospital.


RESULTS
The AN and C groups had normal respiratory function test results and comparable duration of diabetes and quality of metabolic control. (99m)Tc-DTPA clearance did not distinguish the groups. (123)I-MIBG clearance was faster in the AN group than in the C group (mean +/- SD half-time of the radiotracer time-activity curve [T(1/2)], 116.1 +/- 22.8 min in the AN group vs 139.5 +/- 18.3 min in the C group, p = 0.022), which is consistent with neuroadrenergic denervation in the AN group. (123)I-MIBG clearance was independent from (99m)Tc-DTPA clearance. Faster (123)I-MIBG clearance was significantly associated with worse performance in three of the four autonomic tests.


CONCLUSIONS
Neuroadrenergic bronchopulmonary denervation may occur in diabetic patients with AN despite normal clinical and respiratory function findings. Further research is needed to identify clinical and prognostic implications of these findings.
Antonelli Incalzi
Raffaele
R
Department of Internal Medicine, Catholic University, Rome, Italy.
Fuso
Leonello
L
Giordano
Alessandro
A
Pitocco
Dario
D
Maiolo
Carmela
C
Calcagni
Maria Lucia
ML
Ghirlanda
Giovanni
G
D019797:3-Iodobenzylguanidine; D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000150:complications*; D001980:Bronchi / Q000294:innervation; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008168:Lung / Q000294:innervation*; D008297:Male; D008875:Middle Aged; D004369:Pentetic Acid; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D004369:Pentetic Acid