Ultrastructure of the islets of Langerhans in protein-energy malnutrition

Abstract

Significant hormonal changes have been reported in childhood malnutrition, including high serum levels of growth hormone and cortisol, and low levels of circulating insulin. The ultrastructure of the endocrine pancreas in such patients has hitherto not been reported. A light microscopy survey of the pancreatic islets was carried out on 69 malnourished children dying from protein-energy malnutrition. In seven of these cases, a rapid autopsy protocol allowed tissues to be fixed for electron microscopy within 75 minutes of death. This paper presents the first ultrastructural observations on the Islets of Langerhans in childhood protein-energy malnutrition. In all cases, there was a variable degree of degeneration of all cell types with membrane damage, loss of ribosomes, vesiculation and mitochondrial swelling. In addition, the B-cells showed a high proportion of precursor granules compared to crystal forms, possibly accounting for low insulin serum levels reported by other workers. It is suggested that islet cell changes may be related to free radical damage secondary to depletion of glutathione and other antioxidants, as well as relative deficiencies of cysteine and zinc. In addition, the effects of agonal anoxia, and a short fixation delay after death must be considered.