Bunina body formation in amyotrophic lateral sclerosis: a morphometric-statistical and trace element study featuring...

Clinico-environmental and pathological variables were obtained from 10 patients with amyotrophic lateral sclerosis using particle-induced X-ray emission spectrometry (PIXE) and morphometric-statistical analysis. Statistical analysis identified a model that maximally predicts the Bb% (frequency of Bunina bodies) from a selected set, four variables: (1) nucleolar index, (2) magnesium (Mg) content, (3) aluminum (Al) content, and (4) duration of illness. Among them, only the Al content proved important. To determine their chemical nature, electron energy loss spectrometry (EELS) was applied at the ultrastructural level; it revealed that within the motor neuron, Al strongly binds to the Bunina body as well as rough endoplasmic reticulum (rER), and lesser strongly to mitochondria and lipofuscin granule. Thus, it is chemically similar to the rER, providing preferential binding sites to aluminum. The Bunina bodies may be an end-product of the nucleic acid dysmetabolism at rER caused by Al along with Mg depletion.