Globus pallidus glial pigment and its changes with age and chronic illness in childhood.

ABSTRACT

Glial lipopigment appears in the globus pallidus without accumulating in neurons (except for late adolescence) in multiple chronic childhood diseases. In this observational study, we compared the age-related development of glial pigmentation in children with the chronic illness (cystic fibrosis) and children dying acutely. A secondary goal was to search for pallidal neuronal lipopigment in childhood. We recorded pigmentation in the brains of 37 consecutive cystic fibrosis children ranging in age from 0-23 yr and in 17 controls ranging in age from 0-18 yr. We characterized the lipofuscin histochemically and used several regression models to describe the mode of deposition. We observed that in the controls, intraglial pallidal pigment accumulated in 2 forms (relatively large globules and, separately, as clusters of fine granules) at a slow rate during childhood. In cystic fibrosis, both forms of pallidal glial pigment started accumulating at a younger age and were deposited far more rapidly. There was a further increase in the rate of accumulation between 8 and 10 yr of age. We did not encounter pallidal neuronal lipofuscin at any age. These observations are consistent with 2 propositions 1) that globus pallidus glial cells are unique in their ability to accumulate lipofuscin before it accumulates in nearby neurons; and 2) that they are particularly susceptible to some systemic effect of this chronic illness.