Insulin, glucagon, Alzheimer’s and diabetes

What do Alzheimer’s disease (AD) and Type 2 diabetes have in common? For one thing, they are both linked to oxidative brain damage and accelerated aging.

One of the hormones controlling metabolism of insulin* and glucose, Glucagon**-like peptide-1 (GLP-1), is also a potent neuroprotector. Its presence in neurons of the hippocampus is linked to better learning. A synthetic analog of GLP-1, Exenatide, a drug used to treat Type 2 diabetes, accelerated neurogenesis, improved synaptic plasticity and cognitive performancee in animal models. These effects make Exenatide very attractive candidate to treat AD. But how exactly does it work in this case?

Interestingly, Exenatide worked very well in the mice mutants imitating familial AD, but not so well in the mice mutant reproducing synaptic dysfunction in age-dependent AD. This might meat that unlike the age-dependent and familial forms of AD differs in the mechanisms of energy deficits. Previously, insulin has been shown to improve cognitive performance in humans suffering from age-related AD.

Source: Cell Death and Disease (2013) 4, e612; doi:10.1038/cddis.2013.139

*  Insulin: hormone decreasing concentration of glucose in the blood

** Glucagon: hormone increasing concentration of glucose in the blood

Religion and brain health

The way you become a religious believer can influence your brain health later in life

Owen AD, Hayward RD, Koenig HG, Steffens DC, Payne ME (2011) Religious Factors and Hippocampal Atrophy in Late Life. PLoS ONE 6(3): e17006. doi:10.1371/journal.pone.0017006

Despite a growing interest in the ways spiritual beliefs and practices are reflected in brain activity, there have been relatively few studies using neuroimaging data to assess potential relationships between religious factors and structural neuroanatomy. This study examined prospective relationships between religious factors and hippocampal volume change using high-resolution MRI data of a sample of 268 older adults. Religious factors assessed included life-changing religious experiences, spiritual practices, and religious group membership. Hippocampal volumes were analyzed using the GRID program, which is based on a manual point-counting method and allows for semi-automated determination of region of interest volumes. Significantly greater hippocampal atrophy was observed for participants reporting a life-changing religious experience. Significantly greater hippocampal atrophy was also observed from baseline to final assessment among born-again Protestants, Catholics, and those with no religious affiliation, compared with Protestants not identifying as born-again. These associations were not explained by psychosocial or demographic factors, or baseline cerebral volume. Hippocampal volume has been linked to clinical outcomes, such as depression, dementia, and Alzheimer’s Disease. The findings of this study indicate that hippocampal atrophy in late life may be uniquely influenced by certain types of religious factors.

Copyright: © 2011 Owen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.