Early Environmental Origins of Neurodegenerative Disease in Later Life

Center for Children's Health and the Environment, Department of Community and Preventive Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
Environmental Health Perspectives (Impact Factor: 7.98). 10/2005; 113(9):1230-3. DOI: 10.1289/ehp.7571
Source: PubMed


Parkinson disease (PD) and Alzheimer disease (AD), the two most common neurodegenerative disorders in American adults, are of purely genetic origin in a minority of cases and appear in most instances to arise through interactions among genetic and environmental factors. In this article we hypothesize that environmental exposures in early life may be of particular etiologic importance and review evidence for the early environmental origins of neurodegeneration. For PD the first recognized environmental cause, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), was identified in epidemiologic studies of drug abusers. Chemicals experimentally linked to PD include the insecticide rotenone and the herbicides paraquat and maneb; interaction has been observed between paraquat and maneb. In epidemiologic studies, manganese has been linked to parkinsonism. In dementia, lead is associated with increased risk in chronically exposed workers. Exposures of children in early life to lead, polychlorinated biphenyls, and methylmercury have been followed by persistent decrements in intelligence that may presage dementia. To discover new environmental causes of AD and PD, and to characterize relevant gene-environment interactions, we recommend that a large, prospective genetic and epidemiologic study be undertaken that will follow thousands of children from conception (or before) to old age. Additional approaches to etiologic discovery include establishing incidence registries for AD and PD, conducting targeted investigations in high-risk populations, and improving testing of the potential neurologic toxicity of chemicals.

Download full-text


Available from: Leonardo Trasande, Oct 04, 2015
43 Reads
  • Source
    • "We tested the viability of control (e.g. subject CA) versus patient SM derived neuroprogenitors by MTT assay after 48 hour exposure to Mn, Cu, Cd, and MeHg, all of which have been implicated in PD-relevant neurodegenerative processes and/or as PD environmental risk factors (Buzanska et al., 2009; Gorell et al., 1999; Götz et al., 2002; Jomova et al., 2010; Landrigan et al., 2005; Rivera-Mancía et al., 2010; Squitti et al., 2009; Weiss et al., 2002; Willis et al., 2010; Xu et al., 2011). To control for cell line dependent variability , we used multiple clonal hiPSC lines (lines CA4 and CA6 for subject CA; lines SM3, SM4, and SM5 for subject SM). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Poorly-defined interactions between environmental and genetic risk factors underlie Parkinson's disease (PD) etiology. Here we tested the hypothesis that human stem cell derived forebrain neuroprogenitors from patients with known familial risk for early onset PD will exhibit enhanced sensitivity to PD environmental risk factors compared to healthy control subjects without a family history of PD. Two male siblings (SM and PM) with biallelic loss-of-function mutations in PARK2 were identified. Human induced pluripotent stem cells (hiPSCs) from SM, PM, and four control subjects with no known family histories of PD or related neurodegenerative diseases were utilized. We tested the hypothesis that hiPSC-derived neuroprogenitors from patients with PARK2 mutations would show heightened cell death, mitochondrial dysfunction, and reactive oxygen species generation compared to control cells as a result of exposure to heavy metals (PD environmental risk factors). We report that PARK2 mutant neuroprogenitors showed increased cytotoxicity with copper (Cu) and cadmium (Cd) exposure but not manganese (Mn) or methyl mercury (MeHg) relative to control neuroprogenitors. PARK2 mutant neuroprogenitors also showed a substantial increase in mitochondrial fragmentation, initial ROS generation, and loss of mitochondrial membrane potential following Cu exposure. Our data substantiate Cu exposure as an environmental risk factor for PD. Furthermore, we report a shift in the lowest observable effect level (LOEL) for greater sensitivity to Cu-dependent mitochondrial dysfunction in patients SM and PM relative to controls, correlating with their increased genetic risk for PD.
    Neurobiology of Disease 10/2014; 73. DOI:10.1016/j.nbd.2014.10.002 · 5.08 Impact Factor
  • Source
    • "Parkinson's disease (PD) is characterized by a loss of dopamine (DA) neurons in the substantia nigra pars compacta and subsequent loss of DA function in the projection area, namely the striatum. A number of researchers have reported the association between exposure insecticides and herbicides as increasing risk for developing PD (Hertzman et al., 1990; Liou et al., 1997; Landrigan et al., 2005; McCormack et al., 2005; Tanner et al., 2011). In a meta-analysis of 19 studies, Priyadarshi et al. (2000) reported an association between high pesticide use and increased risk for PD with combined odds ratio of 2.15 among farmers, people living close to farms, and those exposed to farm animals. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Heavy metals, various pesticide and herbicides are implicated as risk factors for human health. Paraquat, maneb, and rotenone, carbamate, and organophosphorous insecticides are examples of toxicants for which acute and chronic exposure are associated with multiple neurological disorders including Parkinson's disease. Nevertheless, the role of pesticide exposure in neurodegenerative diseases is not clear-cut, as there are inconsistencies in both the epidemiological and preclinical research. The aim of this short review is to show that at least, some of the inconsistencies are related to individual differences in susceptibility to the effects of neurotoxicants, individual differences that can be traced to the genetic constitution of the individuals and animals studies, i.e., host-based susceptibility.
    Frontiers in Genetics 09/2014; 5:327. DOI:10.3389/fgene.2014.00327
  • Source
    • "The frequency of rs242562 GG genotype is higher in controls compared to that in cases, indicating it may play a protective role. These data are different from a previous study which showed that MAPT polymorphism rs242562 revealed no significant difference between PD patients and controls in Germany, Serbia and Greece [6,18,19]. The sample size, ethnic groups and environment may contribute to the different results. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Microtubule-associated protein tau (MAPT) is a neuronal protein involved in the pathogenesis of several neurodegenerative diseases including Parkinson's Disease (PD). Glycogen synthase kinase 3 beta (GSK3B) catalyzes phosphorylation in multiple sites of tau protein. However, whether or not there is any association between the GSK3B gene alteration, MAPT haplotype and PD remains unexplored in Chinese population, especially in central Chinese population. Here, we aimed at studying the effect of MAPT rs242562 and GSK3B rs334558 on the risk of PD by performing a case-control association study in central China. Our data showed that all PD patients and controls were of MAPT H1/H1 diplotype in our study, thus confirming that the distribution of the MAPT H1 haplotype is common in China. GG genotype of MAPT rs242562 serves protection effect on PD risk in central Chinese population, while genotype of GSK3B rs334558 showed no difference between PD patients and controls. We conclude that the MAPT rs242562 is associated with PD in central China in the background of MAPT H1/H1 diplotype. The GG genotype of rs242562 displays protection against PD in subgroup with GSK3B rs334558 T carrier.
    BMC Neuroscience 04/2014; 15(1):54. DOI:10.1186/1471-2202-15-54 · 2.67 Impact Factor
Show more