No abstract

No abstract

Objective: Protein aggregation leading to central amyloid deposition is implicated in Parkinson’s disease (PD). During disease progression, inflammation and oxidative stress may well invoke humoral immunity against pathological aggregates of PD-associated α-synuclein. The aim was to investigate any possible concurrence between autoimmune responses to α-synuclein monomers, oligomers or fibrils with oxidative stress and inflammation. Methods: The formation of α-synuclein amyloid species was assessed by thioflavin-T assay and atomic force microscopy was employed to confirm their morphology. Serum autoantibody titers to α-synuclein conformations were determined by ELISA. Enzyme activity and concentrations of oxidative stress/inflammatory indicators were evaluated by enzyme and ELISA protocols. Results: In PD patient sera, a differential increase in autoantibody titers to α-synuclein monomers, toxic oligomers or fibrils was associated with boosted levels of the pro-inflammatory cytokine interleukin-6 and tumour necrosis factor-α, but a decrease in interferon-γ concentration. In addition, levels of malondialdehyde were elevated whilst those of glutathione were reduced along with decrements in the activity of the antioxidants: superoxide dismutase, catalase and glutathione transferase. Conclusions: It is hypothesized that the generation of α-synuclein amyloid aggregates allied with oxidative stress and inflammatory reactions may invoke humoral immunity protecting against dopaminergic neuronal death. Hence, humoral immunity is a common integrative factor throughout PD progression which is directed towards prevention of further neurodegeneration, so potential treatment strategies should attempt to maintain PD patient immune status.

Background: Accumulated evidence suggests that insulin resistance and impairments in cerebral insulin receptor signaling may contribute to age-related cognitive deficits and Alzheimer's disease. The enhancement of insulin receptor signaling is, therefore, a promising strategy for the treatment of age-related cognitive disorders. The mitochondrial respiratory chain, being involved in insulinstimulated H 2 O 2 production, has been identified recently as a potential target for the enhancement of insulin signaling. The aim of the present study is to examine: (1) whether a specific respiratory substrate, dicholine salt of succinic acid (CS), can enhance insulin-stimulated insulin receptor autophosphorylation in neurons, and (2) whether CS can ameliorate cognitive deficits of various origins in animal models.

The effects of the novel proline-containing nootropic and neuroprotective dipeptide, noopept (GVS-111, N-phenylacetyl-L-prolylglycine ethyl ester) were investigated in NMRI mice following olfactory bulbectomy. We have shown previously that these animals developed Alzheimer's disease (AD)-like behaviour, morphology and biochemistry including impairment of spatial memory, regional neuronal degeneration and elevated Abeta peptide brain levels. In the current investigation, spatial memory was assessed using the Morris water maze and serum antibodies to in vitro morphologically characterized amyloid structures of both Abeta((25-35)) peptide and equine lysozyme, as well as to neurotrophic glial factor S100b, were analyzed by enzyme-linked immunosorbent assay (ELISA). Noopept (administered at a dose of 0.01 mg/kg for a period of 21 days and during a further 5 days training) restored spatial memory and increased serum antibody levels to oligomers of Abeta((25-35)) peptide but not to equine lysozyme amyloid or S100b protein in bulbectomized animals. The positive immunotropic effect of noopept to Abeta((25-35)) peptide prefibrillar aggregates was more marked in sham-operated compared to the bulbectomized subjects which were characterized by an overall suppression of immunoreactivity. Enhancement of the immune response to Abeta((25-35)) peptide prefibrils caused by noopept may attenuate the neurotoxic consequences of amyloid fibrillization and also be associated with an improvement in spatial memory in bulbectomized mice. These actions of noopept, combined with its previously reported neuroprotective and cholinomimetic properties, suggests that this dipeptide may well be useful for improving cognitive deficits induced by neurodegenerative diseases.