Copper, iron and zinc in Alzheimer's disease senile plaques

Concentrations of copper (Cu), iron (Fe) and zinc (Zn) were measured in the rims and cores of senile plaques (SP) and in the neuropil of the amygdala of nine Alzheimer's disease (AD) patients and in the neuropil of the amygdala of five neurologically normal control subjects using micro particle-induced X-ray emission (micro-PIXE). Comparison of SP rim and core values revealed no significant differences between levels of Cu, Fe or Zn. Zinc and Fe in SP rims and cores were significantly elevated in AD compared with AD neuropil (P<0.05). Copper was significantly elevated (P<0.05) in the rim of SP compared with AD neuropil. Comparison of AD and control neuropil revealed a significant (P<0.05) elevation of Zn in AD subjects. The elevation of these elements in SP in AD is of interest in light of the observation that Cu, Fe and particularly Zn, can accelerate aggregation of amyloid beta peptide.

Neurofibrillary tangles and neuropil threads as a cause of dementia in Parkinson's disease

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common age-related degenerative disorders of the human brain. Both diseases involve multiple neuronal systems and are the consequences of cytoskeletal abnormalities. In AD susceptible neurons produce neurofibrillary changes, while in Parkinson's disease, they develop Lewy bodies. In AD six developmental stages can be distinguished on account of the predictable manner in which the neurofibrillary changes spread across the cerebral cortex. During the course of PD numerous limbic determined parts of the brain undergo specific lesions regulating endocrine and autonomic functions. In general, the extranigral destructions are in themselves not sufficient to produce overt intellectual deterioration. Fully developed Parkinson's disease with concurring incipient Alzheimer's disease is likely to cause impaired cognition.

Synaptic changes in the striatum of schizophrenic cases: a controlled postmortem ultrastructural study

Although studies indicate abnormalities in the striatum of schizophrenic people, little information exists on the synaptic changes that may be present at the ultrastructural level. Autopsy specimens of striatal tissue from people with schizophrenia, normal controls, and psychiatric controls were obtained from the Maryland Brain Collection. Several abnormalities were noted in the schizophrenic group that were not present in the normal or psychiatric controls. In schizophrenic tissue, the density and/or proportion of symmetric synaptic profiles, particularly those ending on spines, were lower in the caudate vs. the putamen, implying an imbalance in inhibitory synaptic transmission between these two structures. The density of perforated synaptic profiles, cortical afferents thought to be involved in synaptic turnover and cognition, was lower in the striatum of the schizophrenic group compared to the control groups. The density of axodendritic synaptic profiles, particularly of the asymmetric type, was decreased in the caudate, but not the putamen, of a subset of schizophrenic cases that were nondyskinetic and off drugs (NDODS). The proportion of asymmetric axospinous synaptic profiles was elevated in the caudate of the NDODS cases in comparison to normal controls. The variety of synapses affected in the schizophrenic group implies the involvement of several neuronal circuits. The alterations observed in the schizophrenic striatum were usually due to changes in the caudate, but not the putamen, which argues against drug-related alterations. Since the striatum, particularly the caudate nucleus, is involved in cognition and emotion, these neuroanatomical changes could underlie, in part, aspects of schizophrenic psychopathology.

ICAM-1 dependent pathway is not involved in the development of neuronal apoptosis after transient focal cerebral ischemia

We examined brain sections from ICAM-1 deficient mice (-/-) and their nontransgenic littermates (+/+) after focal cerebral ischemia and reperfusion (I/R) for the presence of apoptosis. Despite the reduction in necrosis, the -/- mice had apoptotic cells in the ischemic hemisphere as shown by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling (TUNEL) staining and DNA laddering. ICAM-1 deficiency minimizes necrosis but not apoptosis after temporary MCAO in mice, thereby leaving the potential for delayed neuronal cell death despite ICAM-1 inactivation.

Increased apolipoprotein E mRNA in the hippocampus in Alzheimer disease and in rats after entorhinal cortex lesioning

The distribution of apolipoprotein E (ApoE) mRNA was characterized in the hippocampus of humans with Alzheimer disease (AD) and in rats with experimental lesions (unilateral ablation of the entorhinal cortex) that model selected features of AD. In both AD and the lesion model, we observed a shift in the location of astrocytes containing prevalent ApoE mRNA from the neuropil to regions with densely packed neurons. The increased abundance of ApoE mRNA in astrocytes close to neuron cell bodies could be indicative of lipid uptake in regions where neurons are degenerating or where synaptic remodeling is taking place.

Degeneration of neurons, synapses, and neuropil and glial activation in a murine Atm knockout model of ataxia-telangiectasia

Neural degeneration is one of the clinical manifestations of ataxia-telangiectasia, a disorder caused by mutations in the Atm protein kinase gene. However, neural degeneration was not detected with general purpose light microscopic methods in previous studies using several different lines of mice with disrupted Atm genes. Here, we show electron microscopic evidence of degeneration of several different types of neurons in the cerebellar cortex of 2-month-old Atm knockout mice, which is accompanied by glial activation, deterioration of neuropil structure, and both pre- and postsynaptic degeneration. These findings are similar to those in patients with ataxia-telangiectasia, indicating that Atm knockout mice are a useful model to elucidate the mechanisms underlying neurodegeneration in this condition and to develop and test strategies to palliate and prevent the disease.

Spinal cord transection--no loss of distal ventral horn neurons. Modern stereological techniques reveal no transneuronal changes in the ventral horns of the mouse lumbar spinal cord after thoracic cord transection

Anterograde transneuronal degeneration is caused by the loss of afferent input to the nerve cells and may occur in a number of neuronal systems. Transection of the adult spinal cord, causing anterograde transneuronal degeneration in ventral horn neurons, distal to the lesion, has been reported by some authors, while others contend that no such changes take place. The present study was undertaken in order to investigate whether transection of adult mouse thoracic spinal cord induces neuronal death in the ventral horns distal to the lesion. By means of modern stereological techniques such as the optical dissector, the total number of cells in the lumbar ventral horns was estimated 7 weeks after transection. The mean numbers of neurons and glial and endothelial cells were 82,000 versus 89,000, 259,000 versus 301,000, and 129,000 versus 144,000 in the transected (n = 6) and sham-operated animals (n = 5), respectively. These differences were not statistically significant. Furthermore, neuronal soma volume was estimated by another stereological method, the vertical rotator. Mean neuronal soma volume was not significantly different between transected (2762 microns 3) and sham-operated (2617 microns 3) mice. Although no reduction in cell number or neuronal soma volume was observed, the mean volume of the ventral horns in the lumbar segments was significantly less in transected than in sham-operated animals, 2.49 mm3 versus 3.05 mm3 (P < 0.05). In conclusion, the transection of adult mouse thoracic spinal cord does not induce neuronal degeneration in the lumbar ventral horns.

Induction of macrophage migration inhibitory factor messenger ribonucleic acid in rat forebrain by reperfusion

OBJECTIVE

Macrophage migration inhibitory factor (MIF) is a cytokine that has the potential to immobilize and activate monocytes/macrophages. To examine whether MIF may potentially be involved in the pathogenesis of reperfusion injury of the brain, we investigated the expression of MIF in a rat model of reperfusion.

METHODS

A four-vessel occlusion procedure was performed for 30 minutes using male Wistar rats to obtain a moderate reperfusion in the forebrains. Semiquantitatively calibrated reverse-transcription polymerase chain reaction analysis was conducted to examine temporal profiles of messenger ribonucleic acid (mRNA) expression for MIF and macrophage chemoattractant protein 1. MIF protein assays expression was assessed with specific Western blot analysis. For anatomic mapping of MIF, an immunohistochemical study was performed.

RESULTS

Reverse-transcription polymerase chain reaction demonstrated that the mRNA level of MIF increased depending on the duration of reperfusion (< or = 24 h) subsequent to global ischemia. The macrophage chemoattractant protein 1 mRNA was also observed to increase after reperfusional stress, but its maximum expression was reached earlier (1 h after the stress) than was MIF mRNA. Increase of MIF protein was also shown by Western blot. MIF-positive staining was observed in the neuronal processes (neuropil) in the cortex and basal growth ganglia of a rat forebrain.

CONCLUSION

This protein is up-regulated and may modulate immunological reaction in secondary brain damage after ischemia and reperfusion stress.