Kazuma Kaneko

Anti-neuronal autoantibody in Hashimoto's encephalopathy: neuropathological, immunohistochemical, and biochemical analysis of two patients

Hashimotos encephalopathy (HE) is thought to be caused by disorders of immune mechanisms. Although immunologically mediated central nervous system vasculitis or unidentified anti-neuronal autoantibodies have been suspected of causing HE, its pathogenesis is still unclear. For the study presented here, two patients with typical clinical and laboratory/electrophysiological findings of HE were analyzed to clarify the role of anti-neuronal autoantibodies in the pathogenesis of HE. The autopsied brain of one of the patients was histopathologically examined. For Western blotting analysis and immunohistochemistry, serum and purified immunoglobulin G obtained from the other patient were used. Autopsy revealed no evidence of central nervous system vasculitis or other abnormal findings in the brain. The patients serum contained an anti-neuronal autoantibody that immunohistochemically labeled neurons of mouse and human cerebral cortices and reacted with the 36-kDa antigenic protein present in a soluble fraction obtained from human cerebral cortex. Our results indicate that anti-neuronal autoantibodies may be associated with the pathogenesis of HE.

Iron overload and antioxidative role of perivascular astrocytes in aceruloplasminemia

Aceruloplasminemia (ACP) is an inherited disorder of iron metabolism caused by the lack of ceruloplasmin activity; the neuropathological hallmarks are excessive iron deposition, neuronal loss, bizarrely deformed astrocytes, and numerous ‘grumose or foamy spheroid bodies (GFSBs)’. We histopathologically examined two autopsied ACP brains, and observed for the first time that GFSBs form in clusters at the ends of perivascular astrocytic foot processes. Both the deformed astrocytes and the GFSBs contained ferric iron and were intensely immunolabelled with antibodies against the antioxidant proteins ferritin and manganese superoxide dismutase (Mn SOD). Ceruloplasmin is largely produced by perivascular astrocytes in the central nervous system and exhibits a ferroxidase activity that inhibits iron‐associated lipid peroxidation and hydroxyl radical formation; therefore, the lack of ceruloplasmin causes direct oxidative stress on astrocytes. The intense immunolabelling of ferritin and Mn SOD most likely reflects a defensive response to iron‐mediated oxidative stress. This study suggests that astrocytes play key roles in iron trafficking and the detoxification of iron‐mediated free radicals at the blood–brain barrier and in the parenchyma in ACP brain. The antioxidative ability of astrocytes is one of their essential neuroprotective effects, and the decompensation of this ability may lead to secondary neuronal cell death in ACP.

Glial fibrillary acidic protein is greatly modified by oxidative stress in aceruloplasminemia brain.

Aceruloplasminemia is an autosomal recessive disorder of iron metabolism caused by mutations in the ceruloplasmin (Cp) gene. The neuropathological hallmark of this disease is intracellular iron overload, which is thought to lead to neuronal cell death through increased oxidative stress. We evaluated and characterized protein oxidation in the brain of a patient with this disease. The protein carbonyl content in the cerebral cortex of the patient was elevated compared to controls. Furthermore, peptide mass fingerprinting and partial amino acid sequencing identified glial fibrillary acidic protein (GFAP) as the major carbonylated protein in the cerebral cortex of the patient. In conjunction with the facts that Cp mainly localizes to astrocytes in the central nervous system and that astrocytes are loaded with much more iron than neurons in the cerebral cortex, our findings indicate that Cp deficiency may primarily damage astrocytes. We speculate that the dysfunction of astrocytes may be causatively related to neuronal cell loss in aceruloplasminemia.

Quantitative evaluation of expression of iron-metabolism genes in ceruloplasmin-deficient mice.

Aceruloplasminemia is an autosomal recessive disorder caused by mutations in the ceruloplasmin (CP) gene, and is characterized by a unique combination of neurovisceral iron overload and iron deficiency anemia. We generated CP-deficient (CP(-/-)) mice to investigate the functional involvement of CP in iron metabolism. The mice showed a marked iron overload in the liver and mild iron deficiency anemia. We examined the expression of iron-metabolism genes in the duodenum and liver using TaqMan RT-PCR. The divalent metal transporter 1 (DMT1), ferroportin 1 (FPN1), and hephaestin (HEPH) genes were not up-regulated in the duodenum from CP(-/-) mice. These data suggest that the mechanism of hepatic iron overload in aceruloplasminemia is quite different from that in hemochromatoses and atransferrinemia. In the liver, CP(-/-) mice showed no increase of gene expression for DMT1 and transferrin receptors (TFR and TFR2), indicating that none of the known pathways of iron uptake is activated in hepatocytes of CP(-/-) mice. This result supports the hypothesis that CP mainly acts to release iron from cells in the liver.

Severe protein losing enteropathy with intractable diarrhea due to systemic AA amyloidosis, successfully treated with corticosteroid and octreotide.

This report concerns two patients with severe protein losing enteropathy and refractory diarrhea due to AA amyloidosis who were successfully treated with corticosteroid and octreotide. In these patients, biopsied tissues from the gastrointestinal (GI) tract showed extensive deposition of AA amyloid, which was caused by rheumatoid arthritis in one case and was of unidentified etiology in the other. Both patients manifested severe diarrhea unresponsive to conventional treatment with hypoproteinemia, and protein leakage from the small intestine to the ascending colon was confirmed by 99mTc-diethylene triamine pentaacetic acid human serum albumin (HSA-D) scintigraphy. Soon after starting a long-acting somatostatin analogue, octreotide, with co-administration of oral prednisolone, their general status improved in parallel with a rapid decrease in the volume of watery diarrhea and an increase in serum levels of albumin and IgG. Also on 99mTc-HSA-D scintigraphy protein leakage from the GI tract was apparently decreased in both patients. Combination therapy with a somatostatin analogue and corticosteroid may be effective for protein losing enteropathy with intractable diarrhea ascribable to GI amyloidosis. Because of the lack of specific therapies in this serious clinical situation, the described therapy should actively be considered as a therapeutic option not only in AA amyloidosis, but also in other types of systemic amyloidosis.

Extensive brain pathology in a patient with aceruloplasminemia with a prolonged duration of illness

We report the sixth autopsy case of a patient with aceruloplasminemia. He was the younger brother of the first reported autopsy case of this disease. Among autopsy cases with aceruloplasminemia reported to date, he had the longest duration of neurologic disorders. The neuropathologic findings showed that the basal ganglia and dentate nuclei were most severely affected. The most striking finding in the present case was that marked iron deposition was evident in the cerebral cortex. Many enlarged or deformed astrocytes and globular structures, both of which were heavily iron loaded, were found in the cerebral cortex as well as in the basal ganglia. Pyramidal neurons in his cerebral cortex were fewer in number than observed in the previous reported cases. There was a negative correlation between the number of cortical pyramidal neurons and globular structures. The present case clearly indicates that the neuropathologic process in aceruloplasminemia extends beyond the basal ganglia to the cerebral cortex with time.

Increased vulnerability to rotenone-induced neurotoxicity in ceruloplasmin-deficient mice

Ceruloplasmin (Cp) is the strongest ferroxidase in human plasma. Hereditary deficiency of this protein, named aceruloplasminemia, is an interesting model to elucidate the pathogenesis and pathophysiology of neurodegeneration induced by oxidative stress. Enhanced oxidative stress due to excessive iron accumulation is observed in the brains of aceruloplasminemia patients. Rotenone, a selective mitochondrial complex I inhibitor, induces neurodegeneration mimicking Parkinsons disease. We investigated the influence of Cp deficiency upon neurodegeneration using rotenone-treated, Cp-deficient mouse brains. Immunohistochemical examination showed that acrolein, one of the products of lipid peroxides, and ubiquitin were more markedly immunoreacted in the brains of rotenone-treated, Cp-deficient mice than in rotenone-untreated, Cp-deficient or rotenone-treated, wild-type mice. These molecules were localized in neuronal cells. These results suggested that rotenone-induced lipid peroxidation and accumulation of ubiquitin immunoreactivity were enhanced in the absence of Cp. Therefore, Cp may protect neuronal cells from oxidative stress-induced neurodegeneration.

Lupus erythematosus profundus (lupus panniculitis) induced by interferon-β in a multiple sclerosis patient

We report a patient with multiple sclerosis (MS) who developed subcutaneous nodules on the face, shoulders and extremities while being treated with interferon (IFN)-beta-1b. These nodules fluctuated in parallel with myelopathy, and were diagnosed as lupus erythematosus profundus (LEP) based on histopathological findings. The patient showed no relapse of either neurological symptoms or subcutaneous nodules after cessation of IFN-beta-1b. This agent can cause induration and necrosis in the sites of injection but also systemic skin lesions such as LEP ascribable to its immunomodulatory effects.

Thalamic stimulation for disabling tremor in a patient with spinocerebellar degeneration.

Thalamic stimulation alleviated coarse action tremor in a patient with spinocerebellar degeneration (SCD) and led to substantial improvement in daily functioning, though disability from ataxia remained. Intraoperative microrecording revealed a significant correlation between neuronal activity of the ventral intermediate nucleus (Vim) and tremor electromyograms. The tremor-correlated activities of Vim neurons and abolition of the tremor by Vim stimulation suggest that Vim may be related to the generation of action tremor in SCD. Thalamic stimulation can be a useful treatment option for SCD patients with disabling tremor.

Paraneoplastic Sensorimotor Neuropathy and Encephalopathy Associated with Anti-α-Enolase Antibody in a Case of Gastric Adenocarcinoma

Paraneoplastic Sensorimotor Neuropathy and Encephalopathy Associated with Anti-·-Enolase Antibody in a Case of Gastric Adenocarcinoma Kana Tojo a, Takahiko Tokuda a, b, Masahide Yazaki a, Takashi Oide a, Akihiro Nakamura c, Shigeaki Mitsuhashi a, Kazuma Kaneko a, Keiko Maruyamad, Fuyuki Kametani e, Keiichi Higuchi c, Shu-ichi Ikeda a aThird Department of Internal Medicine, Departments of bNeuroplasticity and c Aging Angiology, Shinshu University School of Medicine, Matsumoto, d Department of Neurology, Suwa Red Cross Hospital, and eDepartment of Molecular Neurobiology, Tokyo Institute of Psychiatry, Tokyo, Japan