Thiamine metabolism is critical for glucose metabolism and also vital for brain function,which is susceptible to decline in the elderly. This study aimed to investigate whether thiamine metabolites correlate with cognitive function in the non-demented elderly and their impact factors. Volunteers >60 years old were recruited and their blood thiamine metabolites and Mini-Mental State Examination(MMSE) scores were measured. The apolipoprotein E(APOE) genotype,routine blood parameters,liver and kidney function,and levels of fasting blood glucose and triglycerides were also measured. The results showed that the thiamine diphosphate(TDP) level weakly correlated with MMSE score in the non-demented elderly. Participants with high TDP levels performed better in Recall and Attention and Calculation than those with low TDP. TDP levels were associated with the APOE ε2 allele,body mass index,hemoglobin level,fasting blood glucose,and triglycerides. Our results suggest that TDP,which is easily affected by many factors,impacts cognitive function in the elderly.
Alzheimer’s disease(AD),the most common type of dementia,is a devastating neurodegenerative disorder that seriously afflicts millions of patients and their families due to the lack of effective therapeutic drugs and methods.Elucidating the pathogenesis of this disease has always been a great challenge because AD is complicated with multiple pathophysiological features,including neurodegeneration characterized by progressive synaptic/neuronal loss leading to brain atrophy,brain Aβ deposition forming plaques,Tau hyperphosphorylation constituting neurofibrillary tangles,glial activation and neuroinflammation,and glucose hypometabolism.
Late-onset Alzheimer's disease(LOAD) is an age-related neurodegenerative disorder characterized by gradual loss of synapses and neurons, but its pathogenesis remains to be clarifi ed. Neurons live in an environment constituted by neurons themselves and glial cells. In this review, we propose that the neuronal degeneration in the AD brain is partially caused by diverse environmental factors. We fi rst discuss various environmental stresses and the corresponding responses at different levels. Then we propose some mechanisms underlying the specifi c pathological changes, in particular, hypothalamic-pituitary adrenal axis dysfunction at the systemic level; cerebrovascular dysfunction, metal toxicity, glial activation, and Aβ toxicity at the intercellular level; and kinase–phosphatase imbalance and epigenetic modifi cation at the intracellular level. Finally, we discuss the possibility of developing new strategies for the prevention and treatment of LOAD from the perspective of environmental stress. We conclude that environmental factors play a significant role in the development of LOAD through multiple pathological mechanisms.
Oxidative stress plays a significant role in the pathogenesis of Alzheimer's disease(AD), a devastating disease of the elderly. The brain is more vulnerable than other organs to oxidative stress, and most of the components of neurons(lipids, proteins, and nucleic acids) can be oxidized in AD due to mitochondrial dysfunction, increased metal levels, infl ammation, and β-amyloid(Aβ) peptides. Oxidative stress participates in the development of AD by promoting Aβ deposition, tau hyperphosphorylation, and the subsequent loss of synapses and neurons. The relationship between oxidative stress and AD suggests that oxidative stress is an essential part of the pathological process, and antioxidants may be useful for AD treatment.
