Neurodegenerative alterations of neurons and satellite cells in the human superior cervical ganglion following ischemic stroke

Abstract

The sympathetic nervous system participates in the modulation of cerebrovascular autoregulation. The effect of sympathetic nervous system is realized through neurons of the superior cervical ganglion (SCG) whose sympathetic nerve fibers innervate cerebral arteries. Human sympathetic ganglia alterations related to the injury to peripheral tissue have not been enough analyzed. The aim of the present study was to evaluate the influence of ischemic stroke on the morphology of SCG, and to investigate signs of neurodegenerative alteration, including apoptosis of neuronal and glial cells in the human superior cervical ganglion following ischemic stroke. We investigated human superior cervical ganglia in eight patients who died from ischemic stroke as well as in seven control subjects who died of diseases not related to heart and/or brain disorders using TUNEL method and biotin-streptavidin immunohistochemistry for detecting apoptotic cells and myelin protein and neurofilament in sympathetic neurons and nerve fibres, respectively. The present investigation showed that: (1) signs of neurodegenerative alteration (darkstained and deformed neurons with vacuoles, lymphocytic infiltrates, gliocyte proliferation) were markedly expressed in stroke affected ganglia; (2) apoptotic neuronal and glial cell death was observed in the human SCG in old age and after stroke; (3) heterogenic distribution of apoptotic neurons and glial cells as well as individual variations in both checked groups were identified; (4) higher apoptotic index of sympathetic neurons (89%) in the stroke group than in the control group was found; (5) lower percentage of neurofilament positive neurons (45%) was detected in both checked groups; (6) numerous myelinated fibres in the stroke-affected ganglia and only occasional myelinated fibres in the control group were observed. In summary, findings of this study revealed axotomy-like changes in the human superior cervical ganglia following ischemic stroke.