Fujio Umehara

Immunocytochemical analysis of the cellular infiltrate in the spinal cord lesions in HTLV-I-associated myelopathy

Immunocytochemical staining of spinal cords from five autopsied patients with HAM/TSP was performed using a panel of monoclonal antibodies reactive with T cells, T cell subsets, B cells, macrophages, natural killer cells, IL-2 receptor-positive cells, and HLA-ABC and HLA-DR. In the spinal cords of patients with a shorter duration of illness, CD4+ cells, CD8+ cells and macrophages were evenly distributed in active-chronic inflammatory lesions. In striking contrast, we noted the predominance of CD8+ cells over CD4+ cells in the inactive-chronic inflammatory lesions of patients with longer duration of illness. Natural killer cells, IL-2 receptor-positive cells and B cells were only rarely present in both the active-chronic and inactive-chronic lesions. HLA-ABC was positive in endothelial cells and infiltrating mononuclear cells, and HLA-DR was positive in endothelial cells, microglia and infiltrating mononuclear cells. This study suggests that immune responses in the spinal cord lesions of HAM patients gradually change along with the duration of illness.

A Novel Mutation of desert hedgehog in a Patient with 46,XY Partial Gonadal Dysgenesis Accompanied by Minifascicular Neuropathy

We describe a patient with 46,XY partial gonadal dysgenesis (PGD) who presented with polyneuropathy. Sural nerve pathology revealed peculiar findings characterized by extensive minifascicular formation within the endoneurium and with a decreased density of myelinated fibers. We found, in the patient, a homozygous missense mutation (ATG-->ACG) at the initiating codon in exon 1 of the desert hedgehog (DHH) gene, which predicts a failure of translation of the gene. The same heterozygous mutation was found in the patients father. This is the first report of a human DHH gene mutation, and the findings demonstrate that mutation of the DHH gene may cause 46, XY PGD associated with minifascicular neuropathy.

Cytokine expression in the spinal cord lesions in HTLV-I-associated myelopathy

Immunocytochemical staining of spinal cords from five autopsied patients with HTLV-I-associated myelopathy/ tropical spastic paraparesis was performed using a panel of monoclonal or polyclonal antibodies reactive with interleukin-1/3 (IL-1/3), interleukin-6 (IL-6), tumor necrosis factor (TNF)-a, interferon (IFN)-a, IFN-/3, IFN--yand transforming growth factor (TGF)-/S. In the spinal cords of patients with a shorter duration of illness, IL-l/S, TNF-a, and IFN-7 were expressed on perivascular infiltrating macrophages, astrocytes and microglia in active-chronic inflammatory lesions. In striking contrast, we rarely noted cytokine expression except for IFN-7 in inactive-chronic lesions of patients with longer durations. In situ expression of these cytokines on microglia and astrocytes, in addition to infiltrating mononuclear cells, suggests that glial cells participate in the inflammatory process, especially in active lesions. In addition, the cytokine expression was gradually downregulated along with duration of illness.

Manganese intoxication during total parenteral nutrition : report of two cases and review of the literature

We report two cases of manganese (Mn) intoxication during total parenteral nutrition including manganese (Mn). Both patients showed parkinsonism with psychiatric symptoms and elevated serum Mn levels. T1-weighted magnetic resonance images (MRI) revealed symmetrical high intensity lesions in the globus pallidus. Discontinuation of Mn supplementation and levodopa treatment improved the symptoms and MRI abnormalities in the both patients. Thus, careful attention should be paid to the long-term intravenous administration of Mn.

Spinocerebellar ataxia with axonal neuropathy: consequence of a Tdp1 recessive neomorphic mutation?

Tyrosyl‐DNA phosphodiesterase 1 (Tdp1) cleaves the phosphodiester bond between a covalently stalled topoisomerase I (Topo I) and the 3′ end of DNA. Stalling of Topo I at DNA strand breaks is induced by endogenous DNA damage and the Topo I‐specific anticancer drug camptothecin (CPT). The H493R mutation of Tdp1 causes the neurodegenerative disorder spinocerebellar ataxia with axonal neuropathy (SCAN1). Contrary to the hypothesis that SCAN1 arises from catalytically inactive Tdp1, Tdp1−/− mice are indistinguishable from wild‐type mice, physically, histologically, behaviorally, and electrophysiologically. However, compared to wild‐type mice, Tdp1−/− mice are hypersensitive to CPT and bleomycin but not to etoposide. Consistent with earlier in vitro studies, we show that the H493R Tdp1 mutant protein retains residual activity and becomes covalently trapped on the DNA after CPT treatment of SCAN1 cells. This result provides a direct demonstration that Tdp1 repairs Topo I covalent lesions in vivo and suggests that SCAN1 arises from the recessive neomorphic mutation H493R. This is a novel mechanism for disease since neomorphic mutations are generally dominant.

An autoaggressive process against bystander tissues in HTLV-I-infected individuals : a possible pathomechanism of HAM/TSP

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a well-defined clinico-pathological entity in which the virus infection and the host immune responses are involved in the pathomechanism. It is generally agreed that the virus infection precedes the development of HAM/TSP and the infection is persistent during the course of disease. However, what plays the key role for the development of HAM/TSP remains to be elucidated. In this article, we emphasise the importance of the unique nature of HTLV-I-infected cells, which may have a potential ability to produce viral antigens outside of the blood flow, and we also review a variety of evidences supporting the following proposal. In our hypothesis, the supply of infected T cells from blood flow to central nervous system (CNS) is primary for the development of CNS lesions. Both anatomically determined hemodynamic conditions and adhesion molecule-mediated interactions between circulating infected T cells and endothelial cells may contribute to the localization of the main lesions. Following an induction of the HTLV-I antigens on the surface of infected T cells in CNS compartment, expansion of the responses of immunocompetent T cells against the viral proteins may result in CNS tissue damage which may be mediated by released cytokines. This is the first attempt to implicate a bystander damage mechanism in a human disease as an essential pathomechanism.

HTLV-I proviral DNA amount correlates with infiltrating CD4+ lymphocytes in the spinal cord from patients with HTLV-I-associated myelopathy

A quantitative method utilizing polymerase chain reaction was employed to evaluate the amount of human T-cell leukemia virus type I (HTLV-I) proviral DNA in the affected spinal cords from patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Central nervous system (CNS) tissues were obtained at post-mortem from five patients with HAM/TSP, who vary in the duration of illness from 2.5-10 years, and one patient with adult T-cell leukemia (ATL), who had leukemic cell infiltration in the CNS. The presence of HTLV-I pX and pol sequences in the CNS tissues were demonstrated in all patients examined. In HAM/TSP, the proviral DNA quantified in the thoracic cord was 0.002-2 copies per 100 tissue cells, and that in the peripheral blood mononuclear cells (PBMC) was 2-8 copies per 100 PBMC. The proviral DNA amount in the thoracic cord of the patient with ATL was 0.4 copies per 100 tissue cells. An apparent propensity for the amount of integrated HTLV-I in the thoracic cord to decrease with the disease duration in patients with HAM/TSP was observed. The decline in HTLV-I proviral DNA amount in the thoracic cord lesions was paralleled with the alteration of proportion of CD4+ T lymphocytes in patients with HAM/TSP. These findings suggest that preferential virus reservoir may be infiltrating CD4+ T lymphocytes in the spinal cord lesions of patients with HAM/TSP, and HTLV-I infection in the CNS of patients is declining with the disease duration in spite of the chronic course of neurological manifestations at least in some patients with HAM/TSP.

In vivo protection of a water-soluble derivative of vitamin E, Trolox, against methylmercury-intoxication in the rat

Methylmercury (MeHg) is a well-known neurotoxicant. MeHg-intoxication causes a disturbance in mitochondrial energy metabolism in skeletal muscle and apoptosis in cerebellum. We report the first in vivo effectiveness of antioxidant Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carhoxylic acid), a water soluble vitamin E analog, against the MeHg-induced cellular responses. Treatment with Trolox (6-hydroxy-2.5,7,8-tetramethylchroman-2-carboxylic acid) clearly protects MeHg-treated rat skeletal muscle against the decrease in mitochondrial electron transport system enzyme activities despite the retention of MeHg. Tdt-mediated dUTP nick-end-labeling method clarified that Trolox is effective for protecting cerebellum from MeHg-induced apoptosis. These data indicate that MeHg-mediated oxidative stress plays an important role in the in vivo pathological process of MeHg intoxication. Trolox may prevent some of clinical manifestations of MeHg-intoxication in humans.

Apoptosis of T Lymphocytes in the Spinal Cord Lesions in HTLV-I-Associated Myelopathy: A Possible Mechanism to Control Viral Infection in the Central Nervous System

Abstract. Immunocytochemical staining of spinal cords from five autopsied patients with HAM/TSP was performed using the monoclonal antibody TIA-1, a marker of cytotoxic T lymphocytes (CTL). Many TIA-1+, CD8+ cells are distributed in active inflammatory lesions. The number of TIA-1 + cells is related to the amount of HTLV-I proviral DNA in situ. The protein TIA-1 has been associated with the induction of apoptosis in target cells. In active inflammatory lesions, we found cells undergoing apoptosis, most of them identified as helper-inducer CD45RO T lymphocytes, which were consistent with in vivo cellular tropism of HTLV-I in patients with HAM/TSP. These findings suggest that CTL-induced apoptosis of T lymphocytes may be one of the possible mechanisms which eliminate HTLV-I-infected cells from the central nervous system. In addition, many T lymphocytes in the inflammatory lesions expressed bcl-2 oncoprotein, suggesting that infiltrated T lymphocytes may be resistant to apoptosis. Expression of bcl-2 oncoprotein may explain the longstanding inflammatory process in the central nervous system of HAM/TSP.

Histopathological analysis of four autopsy cases of HTLV-I-associated myelopathy/tropical spastic paraparesis: inflammatory changes occur simultaneously in the entire central nervous system.

Abstract Although brain lesions have been described in some cases with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), little is known about the nature of brain lesion and its relation to the spinal cord lesion. In the present study, we performed histopathological analysis of the brain and the spinal cord of four autopsied cases with HAM/TSP to clarify the relationship between the brain and the spinal cord lesions. In two cases with active-chronic inflammation in the spinal cord, perivascular inflammatory infiltration was also seen in the brain, and the composition of cell subsets was similar both in the spinal cord and in the brain. No active inflammatory change was seen in the brain in two cases with inactive-chronic spinal cord lesions. Inflamed vessels were distributed mainly in the deep white matter and in the area between cerebral cortex and white matter of the brain. In the spinal cord inflamed vessels were mainly seen in the bilateral lateral and the ventral posterior columns. Parenchymal infiltration was diffused in the spinal cord but very sparse in the brain, suggesting the importance of parenchymal infiltration in the destruction of tissues. These results suggest that inflammatory changes occurred simultaneously in the spinal cord and in the brain, and that distribution of inflamed vessels closely correlated with the characteristics of vascular architecture of the brain and the spinal cord, which lead to a slow blood flow. This study may help promote a better understanding of the pathogenesis of HAM/TSP.