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Gadolinium enhancement in acute and chronic-progressive experimental allergic encephalomyelitis in the guinea pig.

Magnetic resonance imaging detects blood-brain barrier disruption after gadolinium-DTPA enhancement of central nervous system lesions of multiple sclerosis. Experimental allergic encephalomyelitis has many clinical and pathological features in common with multiple sclerosis including alterations in the integrity of the blood-brain barrier. We have compared T2-weighted cranial MR images with Gd-DTPA dimeglumine-enhanced T1-weighted images of myelin basic protein-induced acute (Days 8-42 postimmunization) and central nervous system-induced chronic-progressive (Days 70-95 postimmunization) forms of experimental allergic encephalomyelitis in the guinea pig. Although animals from both groups had abnormal T2-weighted images, only the myelin basic protein-acute-EAE animals (Days 14-24 postimmunization) showed enhancement on postcontrast MR studies. The different responses of the acute and chronic diseases may result from different immunogens, severity of disease, or different permeability of the blood-brain barrier. Therefore, gadolinium-DTPA-enhanced, T1-weighted MR images distinguish acutely active and chronic inflammatory lesions in experimental allergic encephalomyelitis.

Animals↗

Both bone marrow- and non-bone marrow-associated factors determine susceptibility to experimental autoimmune encephalomyelitis of BUF and WAG rats.

To determine the feasibility of treatment with allogeneic bone marrow for experimental autoimmune encephalomyelitis, we investigated the susceptibility to experimental autoimmune encephalomyelitis of bone marrow chimeras using BUF, (WAG X BUF)F1 (high responder), and WAG (low responder) rats. In contrast to previous studies in which other rat strains were used, the response was largely determined by the genotype of the grafted bone marrow, but the influence of a non-bone marrow-associated factor was evident. The latter factor was identified as a low corticosterone response in BUF rats and a high corticosterone response in WAG rats. After adrenalectomy, a significant proportion of WAG rats developed clinical experimental autoimmune encephalomyelitis. The bone marrow-associated factor of resistance appeared to be the activity of cyclophosphamide-sensitive suppressor cells. The latter cells were found to interfere with the formation of inflammatory foci in the central nervous system, while corticosterone primarily prevents the clinical expression of lesions.

Animals↗

Early events in canine distemper demyelinating encephalomyelitis.

The early neuropathological development of demyelinating Canine Distemper Encephalomyelitis (CDE) was studied in SPF dogs. Neural tissues were examined up to 30 days post infection (PI). Three phases of activity were observed. The primary event (first observed 8 days PI) was a nonsuppurative encephalomyelitis associated with the initiation of central nervous system (CNS) infection by virus-laden lymphocytes. At 24 days PI noninflammatory demyelination occurred in well defined, subependymal foci. Cell fusion and syncytia formation accompanied this early demyelination. The third phase, found at day 30 PI in one dog showing signs of recovery, was a second wave of nonsuppurative inflammation. The initial encephalomyelitis was widely disseminated throughout the CNS but subsequent demyelination appeared to be initiated from within the ventricular system. Myelin was phagocytosed by endogeneous CNS macrophages often infected with Canine Distemper Virus (CDV). The possible importance of viral induced cell fusion as well as immune factors in the mechanism of demyelination are discussed.

Animals↗

MRI in acute disseminated encephalomyelitis following Semple antirabies vaccine.

I reviewed MRI findings in five patients with acute disseminated encephalomyelitis following vaccination with Semple antirabies vaccine. MRI in two patients with encephalitis features showed multiple white matter lesions in the cerebrum, cerebellar peduncles and brain stem. Two patients who had features of cord involvement showed signal alterations in the cord extending over a few segments. Asymptomatic lesions in the cerebrum were seen in two patients. In a patient with encephalomyelitis MRI 50 days later showed resolution of the lesions. The white matter lesions described were indistinguishable from those seen in acute disseminated encephalomyelitis following other infections.

Adult↗

Experimental allergic encephalomyelitis: a neurourological study.

To assess the neurourological disturbances produced by the perivascular inflammatory process in the acute phase of experimental allergic encephalomyelitis, we carried out a controlled study. Forty-six New Zealand male rabbits were inoculated with an encephalitogenic preparation. Twenty-seven of them developed neurological deficits in an average of 9.3 days postinoculation. A sample of 19 subjects was used as a control. The subjects were studied within 2 days after the manifestation of the first sign of encephalomyelitis. An average of eight successive cystosphincterograms were recorded. Their entire central nervous system was removed intact and suspended in 10% neutral buffered Formalin solution for 2 weeks, then cut into segments, embedded in paraffin, and finally stained with hematoxylin-eosin and Luxol Fast Blue. The results demonstrated a significant reduction of mean vesical capacity, maximum urethral pressure, and mean urethral pressure in the group with encephalomyelitis. Furthermore, we found a significant negative correlation between the average number of cellular perivascular infiltrates in the spinal sacral segment and urethral pressures. The results showed a significant negative correlation between supreamesencephalic inflammation and mean vesical capacity.

Animals↗

Canine distemper and experimental allergic encephalomyelitis in the dog: comparative patterns of demyelination.

The pattern of virus-induced and allergic demyelinating encephalomyelitis in the dog were compared. The predominant pattern of myelin loss in canine distemper (CD) infection was focal, periventricular and was initially noninflammatory. In contrast, sensitization to myelin produced a uniform pattern of central nervous system (CNS) myelinolysis which was disseminated, inflammatory and perivascular. Ultrastructurally, virus-infected neuroglia participated in the demyelination in CD, whereas infiltrating haematogenous mononuclear cells predominated in the lesions of experimental allergic encephalomyelitis (EAE). Areas of predilection within the CNS differed, being influenced by viral spread in CD and by vascular factors in EAE. In CD, the paramyxovirus appears to play a central role in the process of demyelination. In contrast to EAE, however, these studies do not support the view that autoreactivity to myelin contributes to the pathogenesis of CD demyelinating encephalomyelitis.

Animals↗

Inhibition of experimental allergic encephalomyelitis by the alpha-glucosidase inhibitor castanospermine.

The alkaloid castanospermine is a potent inhibitor of oligosaccharide processing in vitro. Our recent findings indicating the importance of carbohydrate moieties in some critical step of the neuro-immunologic inflammatory process of allergic encephalomyelitis prompted us to investigate the effect of castanospermine on this disease process. The alkaloid inhibited passively induced allergic encephalomyelitis in a dose-dependent manner when administered continuously for 7 days beginning at the time of lymphocyte transfer. Although clinical disease was totally inhibited, treated animals did have inflammatory lesions in the central nervous system. These lesions were qualitatively different from those seen in untreated animals in that the inflammatory cells were tightly packed around the vessels and showed little migration into surrounding tissues. Castanospermine also effectively inhibited clinical disease in recipient animals which had had a previous episode of allergic encephalomyelitis. Castanospermine did not alter the disease when treatment was started after the onset of clinical symptoms.

Alkaloids↗

Chronic experimental allergic encephalomyelitis and antibody responses in rabbits immunized with bovine proteolipid apoprotein.

A chronic form of experimental allergic encephalomyelitis can be produced by sensitization of rabbits with bovine myelin proteolipid apoprotein (PLP). To investigate the humoral immune response in this model, serum PLP antibodies were determined by enzyme-linked immunosorbent and dot immunobinding assays. In an initial experiment, 3 PLP-sensitized rabbits with severe chronic experimental allergic encephalomyelitis had a positive antibody response whereas 3 with mild disease, or with no visible clinical disease, had no detectable antibodies against PLP. In a second experiment, 3 rabbits were preimmunized with PLP in incomplete Freund's adjuvant, followed by a single immunization with PLP in complete Freund's adjuvant. These animals developed chronic experimental allergic encephalomyelitis with different progression rates, although all eventually became severely paralyzed. In both experiments the anti-PLP response was maximal before or immediately after disease onset and tended to decline during disease progression. The degree of the anti-PLP response correlated with clinical and histologic disease severity. These data suggest a possible role for humoral factors in the modulation of the chronic EAE induced in PLP-immunized rabbits.

Animals↗

Co-localization of secretoneurin immunoreactivity and macrophage infiltration in the lesions of experimental autoimmune encephalomyelitis.

Secretoneurin, a novel neuropeptide, has recently been shown to attract monocytes. In our present study we have tested whether the local presence of secretoneurin within the CNS of the rat may influence the topographical distribution of inflammatory infiltrates in acute T-cell mediated encephalomyelitis. Experimental allergic encephalomyelitis was induced by passive transfer of myelin basic protein-reactive T-lymphocytes and the distribution of T-cells and macrophages was studied at day 3, 4 and 7 after transfer. In the same sections secretoneurin immunoreactivity was visualized by immunohistochemistry. A clustering of macrophages, but not of T-lymphocytes, was seen at sites of secretoneurin immunoreactivity in all stages of experimental autoimmune encephalomyelitis. Our data indicate for the first time that local neuropeptides may play a role in leucocyte recruitment into inflammatory lesions of the CNS.

Animals↗

Late onset, symptomatic, demyelinating encephalomyelitis in mice infected with MHV-JHM in the presence of maternal antibody.

The presence of maternal antibodies protected suckling C57BL/6 mice from the clinical manifestations of the acute encephalomyelitis caused by mouse hepatitis virus, strain JHM (MHV-JHM), a coronavirus, even though histological evidence of encephalomyelitis was found at early times after inoculation. 100% of infected suckling mice developed a fatal disease in the absence of maternal antibody. By 14 days after inoculation, the brains of all antibody-protected mice examined were nearly normal on histological examination. At 3-8 weeks post-inoculation, approximately 40% of the antibody-protected mice developed a neurological disease characterized by hindlimb paralysis and wasting. Evidence of inflammation and demyelination was apparent in the spinal cord and brainstem. The mice that remained asymptomatic at this time showed few signs of inflammation and none developed clinical disease over the following 9 months. Viral antigen could be detected in most of the mice examined at all times after inoculation, whether symptomatic or not, and was particularly evident in the animals with hindlimb paralysis. MHV-JHM could be consistently cultured from the mice with hindlimb paralysis. These results show that maternal immune factors can completely protect susceptible mice from the acute, fatal, clinical encephalomyelitis caused by MHV-JHM, but cannot prevent the establishment of a latent state and subsequent development of virus-induced, clinically evident, demyelinating disease. This model will be useful for studying the virus and host factors important for the development of MHV-JHM latency and subsequent virus-induced demyelination.

Animals↗

Relapsing encephalomyelitis following transfer of partial immunity to JHM virus.

Mice infected with the JHM strain mouse hepatitis virus (JHMV) develop a fatal encephalomyelitis with evidence of demyelination. It has previously been shown that the adoptive transfer of 5 x 10(7) nylon wool adherent (NWA) spleen cells from immunized donors to lethally infected recipients clears virus from the central nervous system (CNS) and prevents demyelination. Adoptive transfer of a smaller number (1 x 10(7] of NWA spleen cells from immunized donors also protects from death but does not significantly alter virus replication in the CNS during the acute phase of the infection. Moreover, these mice develop a transient non-fatal encephalomyelitis which occurs approximately 3 weeks post-infection. This delayed encephalomyelitis is associated with a mononuclear cell infiltration into the CNS but little or no evidence of virus replication or increased viral antigen. A virus-specific delayed-type hypersensitivity (DTH) response precedes this delayed onset of disease by 24 to 48 h. Resolution of disease correlates with a selective and permanent suppression of the JHMV-specific DTH reactivity. In addition, no virus-specific DTH is detected following adoptive transfer of viral-specific DTH effectors derived from immunized donors. In contrast, these mice respond to a heterologous antigen, KLH, suggesting that the resolution of the encephalitis is accompanied by a profound suppression in viral-specific DTH response.

Animals↗

Sudden onset aphasic hemiplegia: an unusual manifestation of disseminated encephalomyelitis.

The association of the sudden onset of aphasia with hemiplegia, hemisenosry defect, and facial palsy, with MRI evidence of white matter lesions, requires differentiation between multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). We have observed eight patients with such a syndrome, all of whom were originally diagnosed as multiple sclerosis, but who, on closer examination, turned out to be instances of disseminated encephalomyelitis. The patterns of demyelination seen in T2-weighted MRI are quite different in both conditions. In two of our patients, MRI reverted to normal after the treatment; in others, the images remained unchanged. A review of the reported cases of multiple sclerosis presenting with the acute onset of aphasia, reveals that the majority of them are, in reality, instances of acute disseminated encephalomyelitis with a much better prognosis. Most of these cases are monophasic and immunomodulatory treatment is inappropriate.

Adolescent↗

Lesional accumulation of P2X(4) receptor(+) macrophages in rat CNS during experimental autoimmune encephalomyelitis.

P2X(4) receptor (P2X(4)R) is an ion channel gated by ATP. Here we report the presence and distribution of P2X(4)R by immunohistochemical analysis of the rat CNS. In normal control rats, P2X(4)R was expressed by perivascular cells, but not found on parenchymal monocytic cells. We further investigated P2X(4)R expression in experimental autoimmune encephalomyelitis. P2X(4)R(+) cells were mainly identified as infiltrative macrophages in CNS lesions. In the diseased brain, P2X(4)R(+) leukocytic cells were not only found in the direct vicinity of the inflammatory infiltrate, but widespread distribution was seen in the parenchyma. In experimental autoimmune encephalomyelitis spinal cord, the number of P2X(4)R(+) cells was much higher than in brain. P2X(4)R(+) macrophage accumulation reached the maximal levels around day 14 correlating to the clinical severity of experimental autoimmune encephalomyelitis, and this upregulation lasted until the recovery stage of the disease. This implicates a role of P2X(4)R in the inflammatory process of the CNS. In addition, bromodeoxyuridine immunohistochemistry was employed to demonstrate cell proliferation. Only few bromodeoxyuridine+/P2X(4)R+ monocytes/macrophages were observed in both the diseased brain and spinal cord. In conclusion, this is the first demonstration that P2X(4)R presents in autoimmune-lesioned CNS. Consequently, P2X(4)R might be a valuable marker to dissect the local monocyte heterogeneity in autoimmune disease.

Animals↗

Acute disseminated encephalomyelitis presenting with bilateral transient amaurosis.

A 4-year-old male presented with acute disseminated encephalomyelitis with seizures and transient amaurosis after initial symptoms of a flulike febrile infection 1 week earlier. Immunoglobulin M type antibody titers against Mycoplasma pneumoniae were significantly increased in serum and cerebrospinal fluid. The patient improved appreciably on immunosuppressive therapy with immunoglobulin. This patient exemplifies a rare case of acute disseminated encephalomyelitis presenting with bilateral transient amaurosis as a complication of M. pneumoniae infection. Aydin A, Atasever S, Cakmakci H. Acute disseminated encephalomyelitis presenting with bilateral transient amaurosis.

Blindness↗

Neuroimaging features of acute disseminated encephalomyelitis in childhood.

Acute and disseminated demyelination of the central nervous system in children may have many causes. This study reports a retrospective cohort of 10 consecutive pediatric cases (5 to 17 years; mean [S.D.] 12.1 [4.3] years) with a presenting diagnosis of acute disseminated encephalomyelitis and the clinical and radiologic follow-up. The evolution of magnetic resonance imaging abnormalities was determined from serial studies in nine patients with a mean (S.D.) follow-up of 334.2 (312.8) days. Resolution of magnetic resonance imaging T(2) prolongation (i.e., demyelination) within 6 months of presentation was associated most commonly with a final clinical diagnosis of acute disseminated encephalomyelitis (including the multiphasic form), but failed to meet statistical significance (Fisher's exact test; P = 0.083). Incomplete resolution of the magnetic resonance imaging signal abnormalities yielded a statistically significant association (Fisher's exact test; P = 0.048) with an abnormal neurologic outcome. In summary, we conclude that early resolution of magnetic resonance imaging signal abnormalities or recurrent demyelination within 6 months of an acute and disseminated demyelinating event suggests the diagnosis of acute disseminated encephalomyelitis in children, although this association failed to meet statistical significance. However, a statistically significant association between complete resolution of magnetic resonance imaging signal abnormalities and a normal neurologic outcome was observed.

Adolescent↗

Soluble adhesion molecules in acute disseminated encephalomyelitis.

Soluble adhesion molecules are overexpressed in neuroinflammatory disorders. Their synthesis parallels that of their membrane-bound counterparts, which modulate lymphocyte transmigration through the blood-brain barrier. Blood-brain barrier cellular migration may be essential in the evolution of postinfectious inflammatory central nervous system disease. The serum levels of soluble intercellular adhesion molecule-1, soluble vascular adhesion molecule-1, and soluble E-selectin were measured in 12 children with acute disseminated encephalomyelitis and in two control groups (35 healthy and 35 affected by noninflammatory neurologic diseases) of similar age. In patients with acute disseminated encephalomyelitis, soluble E-selectin serum levels were significantly higher (median 113 ng/mL, range 54-144) than in both control groups (median 44, range 31-63, and median 58, range 43-89, respectively; one-way analysis of variance, P < 0.0001); a statistical trend for higher levels of soluble intercellular adhesion molecule-1 was observed in acute disseminated encephalomyelitis subjects, whereas soluble vascular adhesion molecule-1 titers did not differ between the three groups. The specific role played by each of these molecules in lymphocyte extravasation and the differential cytokine modulation of their expression might explain the result. Further larger studies are required including serial measurements and cerebrospinal fluid analysis.

Adolescent↗

[Relapsing remitting multiple sclerosis or multiphasic disseminated encephalomyelitis?].

INTRODUCTION: The imaging presentation of some forms of multiple sclerosis may be misleading. In patients with a history of recent infection or vaccination, especially for adolescents or young adults, the differential diagnosis with acute disseminated encephalomyelitis can be difficult. CASE REPORT: We report an unusual clinical and radiological presentation of multiple sclerosis, mimicking acute disseminated encephalomyelitis. We discuss clinical and radiological differential diagnosis, and the outcome after immunosuppressive treatment. CONCLUSION: Distinguishing between acute disseminated encephalomyelitis and the first relapse of multiple sclerosis can be difficult. Brain imaging is a precious tool for differentiating between the two diseases.

Adolescent↗

Antigen presenting capacity of brain microvasculature in altered peptide ligand modulation of experimental allergic encephalomyelitis.

Co-immunization with an altered peptide ligand (LR) partially protects SJL mice from proteolipid protein peptide 139-151-induced experimental allergic encephalomyelitis [Kuchroo, V.K., Greer, J.M., Kaul, D., Ishioka, G.Y., Franco, A., Sette, A., Sobel, R.A., Lees, M.B., 1994. A single TCR antagonist peptide inhibits experimental allergic encephalomyelitis mediated by a diverse T cell repertoire. J. Immunol. 153, 3326-3336; Santambrogio, L., Lees, M.B., Sobel, R.A., 1998. Altered peptide ligand modulation of experimental allergic encephalomyelitis: immune responses within the CNS. J. Neuroimmunol. 81, 1-13]. Clinical protection was noted despite extensive central nervous system inflammation observed after co-immunization with native and altered peptides. To extend our previous reports on this model, we now compare MHC class II expression and antigen presenting cell activity of cells associated with the blood-brain barrier in diseased and protected mice. Immunohistochemical studies identified MHC class II products on both the endothelial and microglial/macrophage populations. Ex vivo experiments suggested a correlation between the reduced clinical disease observed in the co-immunized mice and the antigen presenting activity of cells at the blood-brain barrier. The results suggest that antigen presenting activity is primarily mediated by macrophage-lineage cells of the central nervous system.

Animals↗