Representing GM, WM, and CSF in standard space. Total intracranial volume (TIV) was determined as the sum of GM, WM, and CSF volumes.[BA17; F(1,328) = 11.6; P = .001], the left lingual gyrus [BA18; F(1,328) = 13.99; P,.0001], the right middle temporal gyrus [BA19; F(1,328) = 32.36; P = .001], and the right Title Loaded From File parahippocampal gyrus [hippocampus; F(1,328) = 11.06; P = .001], and this effect was most significant in the cerebellum for large voxel size (Table 2, Figure 1). Correlation analysis Title Loaded From File showed that the GM volume of these five areas significantly decreased with increasing age in the Bcl-2-A-allele carriers. No significant age-related changes in regional GM volume occurred in the G homozygotes. (Table 2, Figure 1).DiscussionOur study represents the first investigation of Bcl-2 influences on age-related changes in brain morphology in healthy participants over a wide age range. The 23727046 regional GM volumes of the right cerebellum, bilateral lingual gyrus, right middle temporal gyrus, and right parahippocampal gyrus were inversely correlated with age. However, the downward slope of the age-related reduction in GM was steeper in the A-allele carriers than in G homozygotes. Our findings support the hypothesis that Bcl-2 polymorphism may influence aging processes in the brain, and that the G/G allelic variant confers partial protection against agerelated decreases in brain volume. Many neuropathological studies have shown that normal aging is characterized by a substantial and extensive loss of neurons in the cerebral cortex. Morphometric imaging studies have demonstrated that aging predominantly affects the GM, including cortical and deep GM structures and the cerebellum [1,35]. We found an accelerated loss in regional GM volumes with aging, which is consistent with the findings of previous studies [3,35]. Bcl-2 has been shown to regulate neuronal cell death during normal development, and has also been implicated in many models of acute and chronic neurodegeneration [36]. Bcl-2 expression in the brain is up-regulated in Parkinson disease [37] and Alzheimer disease, with Bcl-2 expression increasing with increased disease severity [38]. The over-expression of Bcl-2 inhibits neuronal cell death in vitro [39,40] and in vivo [41,42]. Tanabe et al. [43] showed that endogenous Bcl-2 regulates neuronal cell survival in the central nervous system, and that Bcl-2 deficiency reduces neuronal viability under various adverse cellular conditions. Considering the anti-apoptotic properties of Bcl-2 in neurodegeneration, our findings support those of Machado-Vieira et al. [20], in which the Bcl-2 G/G genotype was 15900046 associated with increased Bcl-2 mRNA and protein expression. Previous studies have observed that higher Bcl-2 expression may protect against dysfunctional calcium homeostasis in bipolar disorder patients [44]. Because Bcl-2 expression in the brain changes with age and increased expression of Bcl-2 may prevent or delay neuronal death [25,42,45], our findings suggest a potential genetic effect of Bcl-2 rs956572 in brain aging. In our study, the protective effect of the homozygous Bcl-2-G allele was limited to the right cerebellum, the bilateral lingual gyrus, the right middle temporal gyrus, and the right parahippocampal gyrus. Thus, these regions may be sensitive to Bcl-2 modulation during brain aging. We observed that the cerebellum was most significantly affected by the Bcl-2 genotype. The Bcl-2 protein is widely expressed during the development of the ne.Representing GM, WM, and CSF in standard space. Total intracranial volume (TIV) was determined as the sum of GM, WM, and CSF volumes.[BA17; F(1,328) = 11.6; P = .001], the left lingual gyrus [BA18; F(1,328) = 13.99; P,.0001], the right middle temporal gyrus [BA19; F(1,328) = 32.36; P = .001], and the right parahippocampal gyrus [hippocampus; F(1,328) = 11.06; P = .001], and this effect was most significant in the cerebellum for large voxel size (Table 2, Figure 1). Correlation analysis showed that the GM volume of these five areas significantly decreased with increasing age in the Bcl-2-A-allele carriers. No significant age-related changes in regional GM volume occurred in the G homozygotes. (Table 2, Figure 1).DiscussionOur study represents the first investigation of Bcl-2 influences on age-related changes in brain morphology in healthy participants over a wide age range. The 23727046 regional GM volumes of the right cerebellum, bilateral lingual gyrus, right middle temporal gyrus, and right parahippocampal gyrus were inversely correlated with age. However, the downward slope of the age-related reduction in GM was steeper in the A-allele carriers than in G homozygotes. Our findings support the hypothesis that Bcl-2 polymorphism may influence aging processes in the brain, and that the G/G allelic variant confers partial protection against agerelated decreases in brain volume. Many neuropathological studies have shown that normal aging is characterized by a substantial and extensive loss of neurons in the cerebral cortex. Morphometric imaging studies have demonstrated that aging predominantly affects the GM, including cortical and deep GM structures and the cerebellum [1,35]. We found an accelerated loss in regional GM volumes with aging, which is consistent with the findings of previous studies [3,35]. Bcl-2 has been shown to regulate neuronal cell death during normal development, and has also been implicated in many models of acute and chronic neurodegeneration [36]. Bcl-2 expression in the brain is up-regulated in Parkinson disease [37] and Alzheimer disease, with Bcl-2 expression increasing with increased disease severity [38]. The over-expression of Bcl-2 inhibits neuronal cell death in vitro [39,40] and in vivo [41,42]. Tanabe et al. [43] showed that endogenous Bcl-2 regulates neuronal cell survival in the central nervous system, and that Bcl-2 deficiency reduces neuronal viability under various adverse cellular conditions. Considering the anti-apoptotic properties of Bcl-2 in neurodegeneration, our findings support those of Machado-Vieira et al. [20], in which the Bcl-2 G/G genotype was 15900046 associated with increased Bcl-2 mRNA and protein expression. Previous studies have observed that higher Bcl-2 expression may protect against dysfunctional calcium homeostasis in bipolar disorder patients [44]. Because Bcl-2 expression in the brain changes with age and increased expression of Bcl-2 may prevent or delay neuronal death [25,42,45], our findings suggest a potential genetic effect of Bcl-2 rs956572 in brain aging. In our study, the protective effect of the homozygous Bcl-2-G allele was limited to the right cerebellum, the bilateral lingual gyrus, the right middle temporal gyrus, and the right parahippocampal gyrus. Thus, these regions may be sensitive to Bcl-2 modulation during brain aging. We observed that the cerebellum was most significantly affected by the Bcl-2 genotype. The Bcl-2 protein is widely expressed during the development of the ne.
