Immunoadsorption for Treatment of Patients with Suspected Alzheimer Dementia and Agonistic Autoantibodies against Alpha1a-Adrenoceptor-Rationale and Design of the IMAD Pilot Study

Beyond the amyloid hypothesis: how current research implicates autoimmunity in Alzheimer's disease pathogenesis

The amyloid hypothesis has so far been at the forefront of explaining the pathogenesis of Alzheimer's Disease (AD), a progressive neurodegenerative disorder that leads to cognitive decline and eventual death. Recent evidence, however, points to additional factors that contribute to the pathogenesis of this disease. These include the neurovascular hypothesis, the mitochondrial cascade hypothesis, the inflammatory hypothesis, the prion hypothesis, the mutational accumulation hypothesis, and the autoimmunity hypothesis. The purpose of this review was to briefly discuss the factors that are associated with autoimmunity in humans, including sex, the gut and lung microbiomes, age, genetics, and environmental factors. Subsequently, it was to examine the rise of autoimmune phenomena in AD, which can be instigated by a blood-brain barrier breakdown, pathogen infections, and dysfunction of the glymphatic system. Lastly, it was to discuss the various ways by which immune system dysregulation leads to AD, immunomodulating therapies, and future directions in the field of autoimmunity and neurodegeneration. A comprehensive account of the recent research done in the field was extracted from PubMed on 31 January 2022, with the keywords "Alzheimer's disease" and "autoantibodies" for the first search input, and "Alzheimer's disease" with "IgG" for the second. From the first search, 19 papers were selected, because they contained recent research on the autoantibodies found in the biofluids of patients with AD. From the second search, four papers were selected. The analysis of the literature has led to support the autoimmune hypothesis in AD. Autoantibodies were found in biofluids (serum/plasma, cerebrospinal fluid) of patients with AD with multiple methods, including ELISA, Mass Spectrometry, and microarray analysis. Through continuous research, the understanding of the synergistic effects of the various components that lead to AD will pave the way for better therapeutic methods and a deeper understanding of the disease.

Involvement of cerebrovascular abnormalities in the pathogenesis and progression of Alzheimer's disease: an adrenergic approach

Alzheimer's disease (AD), as the most common neurodegenerative disease in elder population, is pathologically characterized by β-amyloid (Aβ) plaques, neurofibrillary tangles composed of highly-phosphorylated tau protein and consequently progressive neurodegeneration. However, both Aβ and tau fails to cover the whole pathological process of AD, and most of the Aβ- or tau-based therapeutic strategies are all failed. Increasing lines of evidence from both clinical and preclinical studies have indicated that age-related cerebrovascular dysfunctions, including the changes in cerebrovascular microstructure, blood-brain barrier integrity, cerebrovascular reactivity and cerebral blood flow, accompany or even precede the development of AD-like pathologies. These findings may raise the possibility that cerebrovascular changes are likely pathogenic contributors to the onset and progression of AD. In this review, we provide an appraisal of the cerebrovascular alterations in AD and the relationship to cognitive impairment and AD pathologies. Moreover, the adrenergic mechanisms leading to cerebrovascular and AD pathologies were further discussed. The contributions of early cerebrovascular factors, especially through adrenergic mechanisms, should be considered and treasured in the diagnostic, preventative, and therapeutic approaches to address AD.

KCNA2 Autoimmunity in Progressive Cognitive Impairment: Case Series and Literature Review

Autoimmune dementia is a novel and expanding field which subsumes neuropsychiatric disorders with predominant cognitive impairments due to an underlying autoimmune etiology. Progressive dementias with atypical clinical presentation should trigger a thorough diagnostic approach including testing for neural surface and intracellular antibodies to avoid a delay in accurate diagnosis and initiating appropriate therapy. Here, we present two emerging cases of progressive dementia with co-existing serum autoantibodies against the KCNA2 (potassium voltage-gated channel subfamily A member 2) subunit. We found various cognitive deficits with dominant impairments in the memory domain, particularly in delayed recall. One patient presented a subacute onset of then-persisting cognitive deficits, while the other patient's cognitive impairments progressed more chronically and fluctuated. Cognitive impairments coincided with additional neuropsychiatric symptoms. Both had a potential paraneoplastic background according to their medical history and diagnostic results. We discuss the potential role of KCNA2 autoantibodies in these patients and in general by reviewing the literature. The pathogenetic role of KCNA2 antibodies in cognitive impairment is not well delineated; clinical presentations are heterogeneous, and thus a causal link between antibodies remains questionable. Current evidence indicates an intracellular rather than extracellular epitope. We strongly suggest additional prospective studies to explore KCNA2 antibodies in specifically-defined cohorts of cognitively impaired patients via a systematic assessment of clinical, neuropsychological, neuroimaging, as well as laboratory and CSF (cerebrospinal fluid) parameters, and antibody studies to (1) determine the epitope's location (intracellular vs. extracellular), (2) the mode of action, and (3) seek co-existing, novel pathogenetic autoantibodies in sera and CSF.