Distribution of Disease around the Aortocoeliac Branch of White Carneau Pigeons at Different Ages

Abstract

The distribution of atherosclerotic lesions in the human aorta changes with age. Lipid deposition tends to occur downstream of branch sites in immature vessels but upstream of them at later ages. Comparable age-related distributions of spontaneous and induced lesions have been demonstrated in rabbit aortas. Spontaneous disease is known to develop upstream of the aortocoeliac branch in mature White Carneau pigeons. Using a frequency mapping technique, we investigated whether the same pattern or a downstream one occurs in immature pigeons. Lesions in hatchlings occurred upstream of the branch, to the left of the midline. By 5 months, these lesions had expanded, and a second upstream area, to the right of the midline, was also affected. At later ages, disease frequencies increased in both of these regions but not elsewhere. Thus, contrary to findings in rabbit and human aortas, there was no evidence for a switch from a downstream to an upstream distribution with age. The two rabbit distributions have been attributed to the similar age-related patterns seen in the permeability of the arterial wall; the mature but not the immature pattern of permeability is NO-dependent. The absence of the juvenile disease pattern in pigeons suggests that they might show the NO-dependent pattern of permeability at all ages.