Masamitsu Takatama

Immunoreactivities of p62, an ubiqutin-binding protein, in the spinal anterior horn cells of patients with amyotrophic lateral sclerosis

An ubiquitin-binding protein, p62, is one of the components of the ubiquitin-containing inclusions in several human neurodegenerative diseases. Amyotrophic lateral sclerosis (ALS) is characterized by the presence of skein-like inclusions, Lewy body-like inclusions, and basophilic inclusions in the remaining anterior horn cells, in which these inclusions contain ubiquitin, while the other characteristic inclusions of Bunina type are ubiquitin-negative. We examined the spinal cord from 28 ALS cases including two ALS with dementia and two ALS with basophilic inclusions, using antibody to p62. The results demonstrated that p62 localized in skein-like inclusions, Lewy body-like inclusions and basophilic inclusions. The number of p62-positive inclusions observed in the remaining anterior horn cells of each section was variable among the ALS cases. In contrast, Bunina bodies, that do not contain ubiquitin, were negative for p62. As far as we examined, the 11 non-ALS cases did not show any p62 immunoreactivities in the anterior horn cells. Our results suggested that p62 plays important roles in forming the inclusions and may be associated with the protection of the neurons from degenerative processes involving ubiquitin.

Fragmentation of Golgi apparatus of nigral neurons with α-synuclein-positive inclusions in patients with Parkinson’s disease

We examined whether the Golgi apparatus (GA) is fragmented in nigral neurons in 18 cases with Parkinson’s disease (PD) and in 8 control cases. The nigral neurons in cases with PD showed various degrees of Lewy pathology with α-synuclein immunohistochemistry, and we divided the neurons into three subtypes according to differences in α-synuclein immunoreactivity: (1) neurons without pale bodies or Lewy bodies, (2) neurons with pale bodies, and (3) neurons with Lewy bodies. In controls, we did not observe fragmented GA in nigral neurons by immunocytochemistry with an anti-TGN46 antibody. In PD, the GA was fragmented in 3% of the nigral neurons without inclusions, and in 5% of the neurons with Lewy bodies. In contrast, fragmented GA was noted in 19% of the neurons containing pale bodies. Since pale bodies represent early stages in the development of brainstem Lewy bodies, our results suggest that the cytotoxicity of α-synuclein-positive aggregates is reduced in the process of Lewy body formation.

Optineurin in neurodegenerative diseases

Optineurin is a gene associated with normal tension glaucoma and primary open‐angle glaucoma, one of the major causes of irreversible bilateral blindness. Recently, mutations in the gene encoding optineurin were found in patients with amyotrophic lateral sclerosis (ALS). Immunohistochemical analysis showed aggregation of optineurin in skein‐like inclusions and round hyaline inclusions in the spinal cord, suggesting that optineurin appears to be a more general marker for ALS. However, our detailed examinations demonstrated that optineurin was found not only in ALS‐associated pathological structures, but also in ubiquitin‐positive intraneuronal inclusions in ALS with dementia, basophilic inclusions in the basophilic type of ALS, neurofibrillary tangles and dystrophic neurites in Alzheimers disease, Lewy bodies and Lewy neurites in Parkinsons disease, ballooned neurons in Creutzfeldt‐Jakob disease, glial cytoplasmic inclusions in multiple system atrophy, and Pick bodies in Pick disease. With respect to optineurin‐positive basophilic inclusions, these structures showed variable immunoreactivities for ubiquitin; some structures were obviously ubiquitin‐positive, while others were negative for the protein, suggesting that optineurin expression was not always associated with the expression of ubiquitin. This study indicates that optineurin is widely distributed in neurodegenerative conditions; however, its significance is obscure.

Ultrastructure of diffuse plaques in senile dementia of the Alzheimer type: comparison with primitive plaques

SummaryWe compared the ultrastructure between diffuse and primitive plaques in the brains of senile dementia, using pairs of routine electron microscopic ultrathin sections and adjacent semithin sections, which were immunolabeled for β protein. In the frontal cortex, amyloid fibrils were rarely seen in a minority of diffuse plaques, suggesting an initial stage of the diffuse plaques. A majority of the diffuse plaques had electrondense material and/or amyloid fibrils between cell processes in part of but not the entire β/A4-immunoreactive areas. Small degenerating neurites were often seen with apparent amyloid fibrils in the diffuse plaques, and these were considered to be in an advanced stage. The size and number of degenerating neurites were proportional to the amount of amyloid. Bundles of amyloid fibrils were occasionally surrounded by astroglial processes forming gap junctions. Neurons were found within some diffuse plaques, but capillaries were rarely seen. In contrast, in the temporal cortex, the diffuse plaques were smaller, and even these small ones had apparent amyloid fibrils. The amount of amyloid correlated significantly with plaque size in the temporal cortices, but not in the frontal cortices. Most of the diffuse plaques of the frontal lobe remained as advanced diffuse plaques (apparent amyloid with occasional astroglia and some degenerating neurites) for a long time, and did not transformed into primitive plaques, whereas the temporal diffuse plaques tended to transform into primitive plaques.

Oculomotor nuclear pathology in amyotrophic lateral sclerosis

SummaryWe examined the oculomotor and/or trochlear nuclei of 27 amytrophic lateral sclerosis (ALS) patients and 10 controls by histological and immunohistological methods. Their neurons were relatively well preserved. In 7 of 22 sporadic ALS patients (including 3/3 ALS with ophthalmoplegia) and in 4 of 5 ALS patients with dementia, some morphological changes similar to those in anterior horns (Bunina bodies, ubiquitin-positive skein-like inclusions, Lewy body-like inclusions, conglomerate inclusions and spheroids) were rarely, but clearly seen. These changes were not observed in controls. Our results suggest that the oculomotor and trochlear nuclei in ALS patients are slightly affected in a manner similar to that in the anterior horns, but the degree is less than that necessary for development of ophthalmoplegia in the majority of ALS patients.

Regional distribution of TDP-43 inclusions in Alzheimer disease (AD) brains: Their relation to AD common pathology

Initially, trans activation responsive region (TAR)‐DNA‐binding protein 43 (TDP‐43) was considered to be a disease‐specific component of ubiquitin‐positive and tau‐negative inclusions in the brains of patients with frontotemporal lobar degeneration with ubiquitin‐positive inclusions (FTLD‐U) and amyotrophic lateral sclerosis (ALS); however, it is now widely known that this protein also abnormally accumulates in neurons in other neurodegenerative diseases. On the basis of observation mainly in the medial temporal lobe, TDP‐43‐immunoreactive neuronal inclusions have been detected in 20–30% of Alzheimer disease (AD) brains. However, it is controversial whether these cases represent a combined disease, that is, mixed AD/FTLD‐U. To address this issue, it is necessary to obtain more knowledge on the region‐specific distribution of TDP‐43 immunoreactivity and also about its relationship to AD common pathology. Here, we describe abnormal TDP‐43 immunoreactivity in the medial temporal lobe in 5/16 AD patients (31%). Most of the depositions were cytoplasmic inclusions, mainly located in the subiculum and parahippocampal gyrus and rarely in dentate granular cells of the hippocampus. TDP‐43‐positive inclusions and senile plaque/neurofibrillary tangle distribution were not always identical, and intracellular colocalizations of TDP‐43 and phospho‐tau were also infrequent. The cases showing TDP‐43‐positive inclusions in the medial temporal lobe also showed abnormally highly dense TDP‐43 immunoreactivity in the frontal, but not in the parietal and occipital cortices. Intracellularly, TDP‐43‐positive inclusions were highly ubiquitinated and colocalized with p62 immunoreactivity as well. Our findings suggest that abnormal TDP‐43 deposition and AD pathology (formation of senile plaques and neurofibrillary tangles) might occur independently. However, taken together with the results of previous reports, the distribution of TDP‐43 immunoreactivity in the hippocampus and frontal cortex in AD appear to be varying. We consider that it is still too early to determine that the TDP‐43 accumulation is a part of AD pathology or result from a completely independent pathology.

ELECTRON MICROSCOPIC STUDIES ON THE MORPHOGENESIS OF FIBRINOID DEGENERATION IN THE MESENTERIC ARTERIES OF HYPERTENSIVE RATS.

† Department of Pathology, School of Medicine, Gunma University, Maebashi, Japan. The direct cause of apoplectic cerebral hemorrhage (hypertensive intracerebral massive hemorrhage) is the so-called angionecrosis of intracerebral arteries. It is, both histologically and histochemically, very similar to fibrinoid degeneration in the systemic arteries of hypertensive rats which is induced by surgical constriction of the bilateral renal arteries (Ooneda and associates’; Takatama2) . The fibrinoid degeration is observed not only in hypertensive, allergic and collagen diseases, but also in other miscellaneous pathologic conditions (Matsuyama and co-workers3) . As to the morphogenesis of the degeneration, which is characterized by the presence of fibrinoid substance in vascular

Anterior horn cells with abnormal TDP-43 immunoreactivities show fragmentation of the Golgi apparatus in ALS.

Recently, TAR DNA-binding protein of 43-kDa (TDP-43) was identified as a major component of ubiquitinated neuronal cytoplasmic inclusions observed in lower motor neurons in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitinated inclusions. We herein investigated the relationship between TDP-43 immunoreactivities and fragmentation of the Golgi apparatus (GA). Each mirror section of spinal cord tissues in 10 ALS and 3 control cases were immunostained with polyclonal anti-TDP-43 and polyclonal anti-trans-Golgi-network (TGN)-46 antibodies. The neurons were divided into subtypes according to differences in TDP-43 immunoreactivities, and we examined the morphological changes of GA in each type. We divided the neurons into four subtypes according to the observed differences in TDP-43 immunoreactivities, Type A: neurons showing normal nuclear staining, Type B: neurons showing a loss of normal nuclear staining and a few granular cytoplasmic immunoreactivities, Type C: neurons showing a lot of granular immunoreactivities and no inclusions, Type D: neurons with inclusions. All of the neurons in Type A showed normal GA profiles, however, almost all of the neurons with abnormal TDP-43 immunoreactivities (Type B-D) showed GA fragmentation. These results suggest that neurons with abnormal TDP-43 immunoreactivities are associated with dysfunction of the secretory pathway in motor neurons.

Transferrin localizes in Bunina bodies in amyotrophic lateral sclerosis

Transferrin, an iron-binding protein, plays an important role in the transport and delivery of circulating ferric iron to the tissues. Amyotrophic lateral sclerosis (ALS) is characterized by the presence of Bunina bodies, skein-like inclusions, Lewy body-like inclusions/round inclusions, and basophilic inclusions in the remaining anterior horn cells in the spinal cord. We examined transverse paraffin sections of lumbar spinal cords from 12 ALS cases including two ALS with dementia and two ALS with basophilic inclusions, using antibodies to human transferrin. The results demonstrated that transferrin localized in Bunina bodies and some of the basophilic inclusions. In contrast, skein-like inclusions and Lewy body-like inclusions or round inclusions did not show obviously detectable transferrin immunoreactivities. Our findings suggest that although the mechanisms underlying transferrin accumulation in Bunina bodies and basophilic inclusions are unknown, transferrin could be involved in forming these inclusions. Furthermore, following cystatin C, transferrin is the second protein that localizes in the Bunina bodies.

A case of segmental mediolytic arteriopathy involving both intracranial and intraabdominal arteries

Segmental mediolytic arteriopathy (SMA) is an uncommon nonatherosclerotic and nonvasculitic arteriopathy. This disease is characterized by lytic degeneration of the arterial media, intramural dissection and thrombosed or ruptured aneurysm. SMA mainly involves the intraabdominal arterial system, resulting in intraabdominal and retroperitoneal hemorrhage. However, only a few cases of SMA with involvement of intracranial arteries have been reported. Here, we present a case of SMA developing subarachnoid hemorrhage due to dissection of the internal carotid and vertebral arteries. This patient was a 48-year-old male who died 13 days after admission for sudden loss of consciousness. Computed tomography showed subarachnoid hemorrhage. At autopsy, the affected vessels included the right vertebral, left internal carotid, superior mesenteric, bilateral renal and left external iliac arteries. Histopathologically, the arteries showed segmental lytic degeneration and disappearance of medial smooth muscle cells, medial dissection and formation of pseudo-aneurysms, the wall of which consisted of a thin membrane of the adventitia. These histopathological features mimicked an entire wall dissection type of intracranial dissecting aneurysm, which exclusively affects the vertebro-basilar system. Thus, SMA should be considered a possible underlying disease in patients with spontaneous dissection of intracranial arteries.