Carotid body hyperplasia in cystic fibrosis and cyanotic heart disease. A combined morphometric, ultrastructural, and biochemical study.

A combined morphometric, ultrastructural, and biochemical study was done on carotid bodies (CBs) obtained at autopsy from 213 patients in a pediatric and young adult population. The objective was to determine whether this group had statistically significant differences in sudden infant death syndrome (SIDS, n = 38), cystic fibrosis (CF, n = 30) and cyanotic heart disease (CHD, n = 17), compared with an age-matched control population (n = 128). Average combined weights of CBs in CF and CHD were significantly greater than those of controls in most age intervals (Student t test, P less than 0.05), and computerized planimetry showed an increase in both total surface area and area of "functional" parenchyma. There was diminished chief cell argyrophilia in 72% of CF CBs, and in 8 cases studied ultrastructurally there was moderate to marked depletion of dense-core neurosecretory granules. Most CBs from patients with CHD showed intense cytoplasmic argyrophilia similar to that of controls. Quantitative analysis for tissue catecholamines showed that dopamine was present in greatest concentration in each group of patients but was significantly elevated in CHD. There were no significant differences in morphometry, ultrastructure, or catecholamine content of CBs from SIDS victims, compared with age-related controls. These data add further support to CBs having a chemoreceptor role in humans with compensatory hypertrophy and hyperplasia occurring in most patients with chronic hypoxia due to CF and CHD. There were no significant findings to indicate that CBs play a direct role in the etiopathogenesis of SIDS.