Wu J, Basha MR, Brock B, Cox DP, Cardozo-Pelaez F, McPherson CA, Harry J, Rice DC, Maloney B, Chen D, Lahiri DK, Zawia NH. Alzheimer’s disease (AD)-like pathology in aged monkeys after infantile exposure to environmental metal lead (Pb): evidence for a developmental origin and environmental link for AD. J Neurosci. 2008 Jan 2 ; 28(1):3-9. Pubmed Abstract

Comments on News and Primary Papers

Comment by: Lary Walker, ARF Advisor
Submitted 7 January 2008

The developing brain is particularly sensitive to environmental insults, including infection, radiation, and toxins. Because the brain is still growing, differentiating, & establishing connections at this time, such hazards can influence brain structure and function throughout the lifespan. For example, the risk of schizophrenia, a disorder that generally emerges in early adulthood, appears to be increased by specific maternal infections prenatally (Brown, 2006). Relatively little research has addressed the question of whether Alzheimer disease and other age-associated neurodegenerative disorders also might be promoted by brain changes incurred during development.
……. the study of Wu and colleagues opens the door for further work in this area. These researchers studied the brains of eight female cynomolgus monkeys (Macaca fascicularis), four of which were exposed to low but biologically significant levels of lead acetate for the first 400 days of life. The animals showed no obvious health impairments over the ensuing years, but postmortem evaluation of the brains at 23 years of age found elevated mRNA for β-amyloid precursor protein (APP)……….

These initial findings suggest - early lead exposure can promote the conditions for neurodegeneration-associated mechanisms later in life, and as such warrant further investigation. In addition, it is worth asking whether other types of early-life insult might have similar effects. Epidemiological studies could be informative in this regard, as has been the case for schizophrenia………

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Comment by: Changiz Geula (Disclosure)
Submitted 16 January 2008 Posted 16 January 2008

In this report, Wu et al. provide intriguing evidence that lead exposure during early postnatal life in female Macaca Fascicularis monkeys results in altered DNA methylation, oxidative stress, and changes related to amyloid pathology in late life…….. These observations are provocative and enhance the possibility that early prenatal and/or postnatal events play a crucial role in initiation of disease. They invoke the probability that events in early life, including lead exposure, contribute to Alzheimer disease (AD) in late life. This line of research is worthy of pursuit in a larger cohort and as epidemiological study in humans……..

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Comment by: Gerta Farber
Submitted 24 January 2008 Posted 24 January 2008

This new study indicates “evidence for a developmental origin and environmental link for Alzheimer’s disease.” The major unresolved question is the timing and the triggering leading to the disease, but data does suggest that a pathogenesis is influenced by early life exposures, with results not significant until later in life.
Genetic celiac disease has long been associated with neurologic and psychiatric disorders. Mayo Clinic has discovered a relationship of CD and dementia. When I was diagnosed with CD 6 years ago, at the age of 75, it was also revealed that in addition to my mother’s autopsy in 1980 for AD, she possessed the gene responsible for my currently disabling CD.

I am aware that the past deaths of eight family members were attributed to “dementia,” with the four most recent of those diagnosed as AD. My sibling has currently also been diagnosed with AD, as well as possessing a genetic celiac gene.

This new evidence of an environmental trigger to AD would warrant a study of gluten toxicity as a possible foundation.

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How and when environmental agents and dietary factors affect the course of Alzheimer’s disease: the “LEARn” model (latent early-life associated regulation) may explain the triggering of AD.

Lahiri DK, Maloney B, Basha MR, Ge YW, Zawia NH.
Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA. dlahiri@iupui.edu

Alzheimer’s disease (AD) is currently the most prominent form of dementia among the elderly. Although AD manifests in late adult life, it is not clear when the disease actually starts and how long the neuropathological processes take to develop AD…… The major unresolved question is the timing and the nature of triggering leading to AD. Is it an early or developmental and/or late phenomenon and what are the factors that trigger the cascade of pathobiochemical processes? To explain the etiology of AD one should consider the neuropathological features, such as neuronal cell death, tau tangles, and amyloid plaque, and environmental factors associated with AD, such as diet, toxicological exposure, and hormonal factors. …….. we propose a “Latent Early-Life Associated Regulation” (LEARn) model, which postulates a latent expression of specific genes triggered at the developmental stage. According to this model, environmental agents , intrinsic factors , and dietary factors perturb gene regulation in a long-term fashion, beginning at early developmental stages; however, these perturbations do not have pathological results until significantly later in life. ……….. The LEARn model may explain the etiology of AD and other neuropsychiatric and developmental disorders.

PMID: 17430250 [PubMed - indexed for MEDLINE]