In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia associated with anti-GAD antibodies, the cerebellar type of Hashimoto’s encephalopathy, primary autoimmune cerebellar ataxia, gluten ataxia, Miller Fisher syndrome, ataxia associated with systemic lupus erythematosus, and paraneoplastic cerebellar degeneration. Humoral mechanisms, cell-mediated immunity, inflammation, and vascular injuries contribute to the cerebellar deficits in immune-mediated cerebellar ataxias.
Objective:To clarify the genetic, clinicopathologic, and neuroimaging characteristics of patients with hereditary diffuse leukoencephalopathy with spheroids (HDLS) with the colony stimulating factor 1 receptor (CSF-1R) mutation.Methods:We performed molecular genetic analysis of CSF-1R in patients with HDLS. Detailed clinical and neuroimaging findings were retrospectively investigated. Five patients were examined neuropathologically.Results:We found 6 different CSF-1R mutations in 7 index patients from unrelated Japanese families. The CSF-1R mutations included 3 novel mutations and 1 known missense mutation at evolutionarily conserved amino acids, and 1 novel splice-site mutation. We identified a novel frameshift mutation. Reverse transcription PCR analysis revealed that the frameshift mutation causes nonsense-mediated mRNA decay by generating a premature stop codon, suggesting that haploinsufficiency of CSF-1R is sufficient to cause HDLS. Western blot analysis revealed that the expression level of CSF-1R in the brain from the patients was lower than from control subjects. The characteristic MRI findings were the involvement of the white matter and thinning of the corpus callosum with signal alteration, and sequential analysis revealed that the white matter lesions and cerebral atrophy relentlessly progressed with disease duration. Spotty calcifications in the white matter were frequently observed by CT. Neuropathologic analysis revealed that microglia in the brains of the patients demonstrated distinct morphology and distribution.Conclusions:These findings suggest that patients with HDLS, irrespective of mutation type in CSF-1R, show characteristic clinical and neuroimaging features, and that perturbation of CSF-1R signaling by haploinsufficiency may play a role in microglial dysfunction leading to the pathogenesis of HDLS.
(62)Cu-ATSM PET imaging demonstrated increased oxidative stress based on an over-reductive state, primarily in the motor cortex, in patients with ALS. The magnitude of oxidative stress correlated well with clinical severity, indicating that it may be associated with neurodegenerative changes in ALS.
Background: Hashimoto’s encephalopathy (HE) presents with a variety of neurologic and neuropsychiatric features. In this study, we investigated the clinical and immunological profiles of the cerebellar ataxic form of HE. Methods: The clinical features, treatments, laboratory features, brain imaging, and serum anti-NH2-terminal of α-enolase autoantibodies (anti-NAE Abs), a useful diagnostic marker for HE, were investigated in 13 patients who presented with sporadic adult-onset cerebellar ataxia and fulfilled the HE diagnostic criteria (antithyroid Abs and responsiveness to immunotherapy). Results: All of the patients presented with truncal ataxia, but nystagmus was uncommon (17%). Eight patients had an insidious onset that mimicked spinocerebellar degeneration (SCD), but brain imaging showed little or no cerebellar atrophy in all of the patients. Those patients with serum anti-NAE Abs (n = 8) did not have nystagmus and tended to respond better to immunotherapy than the anti-NAE Ab-negative patients. Conclusion: The present study suggests that insidious adult-onset and truncal ataxia are common in the cerebellar ataxic form of HE, which mimics SCD, but that nystagmus and severe cerebellar atrophy are uncommon. Antithyroid and anti-NAE Abs may be useful for diagnosing cerebellar ataxic HE.
Tau aggregation and amyloid β protein (Aβ) deposition are the main causes of Alzheimer's disease (AD). Peroxisome proliferator-activated receptor γ (PPARγ) activation modulates Aβ production. To test whether the PPARγ agonist pioglitazone (PIO) is also effective in preventing tau aggregation in AD, we used a cellular model in which wild-type tau protein (4R0N) is overexpressed (M1C cells) (Hamano et al., 2012) as well as primary neuronal cultures. PIO reduced both phosphorylated and total tau levels, and inactivated glycogen synthase kinase 3β, a major tau kinase, associated with activation of Akt. In addition, PIO decreased cleaved caspase3 and C-terminal truncated tau species by caspase, which is expected to decrease tau aggregation. A fractionation study showed that PIO reduced high molecular-weight (120 kDa), oligomeric tau species in Tris Insoluble, sarkosyl-soluble fractions. Tau decrease was reversed by adding GW9662, a PPARγ antagonist. Together, our current results support the idea that PPARγ agonists may be useful therapeutic agents for AD.
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