Impact of metabolic dysfunction on cognition in humans

LPC20K modified from krill oil ameliorates the scopolamine-induced cognitive impairment

Alzheimer's disease (AD) is characterized by cognitive impairment. It is common in the elderly. Etiologically, dysfunction of cholinergic neurotransmitter system is prominent in AD. However, disease modifying drug for AD is still unavailable. We hypothesized that krill oil and modified krill oil containing 20 % lysophosphatidylcholine-docosahexaenoic acid (LPC-DHA, LPC20K) could play a crucial role in AD by improving cognitive functions measured by several behavioral tests. We found that LPC20K could ameliorate short-term, long-term, spatial, and object recognition memory under cholinergic hypofunction states. To find the underlying mechanism involved in the effect of LPC20K on cognitive function, we investigated changes of signaling molecules using Western blotting. Expression levels of protein kinase C zeta (PKCζ) and postsynaptic density protein 95 (PSD-95), and phosphorylation levels of extracellular signal-regulated kinase (ERK), Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ), and cAMP response element-binding protein (CREB) were significantly increased in LPC20K-administered group compared to those in the memory impairment group. Moreover, the expression levels of BDNF were temporally increased especially 6 or 9 h after administration of LPC20K compared with the control group. These results suggest that LPC20K could ameliorate memory impairment caused by hypocholinergic state by enhancing the expression levels of PKCζ and PSD-95, and phosphorylation levels of ERK, CaMKⅡ and CREB and increasing BDNF expression levels. Therefore, LPC20K could be used as a dietary supplement against cognitive impairment observed in diseases such as AD with a hypocholinergic state.

Shared Risk Factors between Dementia and Atherosclerotic Cardiovascular Disease

Alzheimer’s disease is the most common form of dementia, and the prodromal phases of Alzheimer’s disease can last for decades. Vascular dementia is the second most common form of dementia and is distinguished from Alzheimer’s disease by evidence of previous stroke or hemorrhage and current cerebrovascular disease. A compiled group of vascular-related dementias (vascular dementia and unspecified dementia) is often referred to as non-Alzheimer dementia. Recent evidence indicates that preventing dementia by lifestyle interventions early in life with a focus on reducing cardiovascular risk factors is a promising strategy for reducing future risk. Approximately 40% of dementia cases is estimated to be preventable by targeting modifiable, primarily cardiovascular risk factors. The aim of this review is to describe the association between risk factors for atherosclerotic cardiovascular disease and the risk of Alzheimer’s disease and non-Alzheimer dementia by providing an overview of the current evidence and to shed light on possible shared pathogenic pathways between dementia and cardiovascular disease. The included risk factors are body mass index (BMI); plasma triglyceride-, high-density lipoprotein (HDL) cholesterol-, low-density lipoprotein (LDL) cholesterol-, and total cholesterol concentrations; hypertension; diabetes; non-alcoholic fatty liver disease (NAFLD); physical inactivity; smoking; diet; the gut microbiome; and genetics. Furthermore, we aim to disentangle the difference between associations of risk factors in midlife as compared with in late life.

HDL Cholesterol and Non-Cardiovascular Disease: A Narrative Review

High density lipoprotein (HDL) cholesterol has traditionally been considered the “good cholesterol”, and most of the research regarding HDL cholesterol has for decades revolved around the possible role of HDL in atherosclerosis and its therapeutic potential within atherosclerotic cardiovascular disease. Randomized trials aiming at increasing HDL cholesterol have, however, failed and left questions to what role HDL cholesterol plays in human health and disease. Recent observational studies involving non-cardiovascular diseases have shown that high levels of HDL cholesterol are not necessarily associated with beneficial outcomes as observed for age-related macular degeneration, type II diabetes, dementia, infection, and mortality. In this narrative review, we discuss these interesting associations between HDL cholesterol and non-cardiovascular diseases, covering observational studies, human genetics, and plausible mechanisms.