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Transforming growth factor-β1 (TGF-β1) is a neurotrophic factor that exerts neuroprotective effects against β-amyloid-induced neurodegeneration. Recently, a specific impairment of the TGF-β1 signaling pathway has been demonstrated in Alzheimer's disease (AD) brain. TGF-β1 is also involved in the pathogenesis of depressive disorders, which may occur in 30-40% of AD patients. The TGF-β1 gene contains single nucleotide polymorphisms (SNPs) at codon +10 (T/C) and +25 (G/C), which are known to influence the level of expression of TGF-β1. We investigated TGF-β1 +10 (T/C) and +25 (G/C) SNPs and allele frequencies in 131 sporadic AD patients and in 135 healthy age- and sex-matched controls. Genotypes of the TGF-β1 SNPs at codon +10 (T/C) and +25 (G/C) did not differ between AD patients and controls, whereas the allele frequencies of codon +10 polymorphism showed a significant difference (P = 0.0306). We also found a different distribution of the +10 (C/C) phenotype (continuity-corrected χ(2) test with one degree of freedom = 4.460, P = 0.0347) between late onset AD (LOAD) patients and controls (P = 0.0126), but not between early onset AD (EOAD) patients and controls. In addition, the presence of the C/C genotype increased the risk of LOAD regardless of the status of apolipoprotein E4 (odds ratio [OR] = 2.34; 95% CI = 1.19-4.59). Compared to patients bearing the T/T and C/T polymorphisms, LOAD TGF-β1 C/C carriers also showed > 5-fold risk to develop depressive symptoms independently of a history of depression (OR = 5.50; 95% CI = 1.33-22.69). An association was also found between the TGF-β1 C/C genotype and the severity of depressive symptoms (HAM-D(17) ≥ 14) (P < 0.05). These results suggest that the CC genotype of the TGF-β1 gene increases the risk to develop LOAD and is also associated with depressive symptoms in AD., (Copyright © 2011 Elsevier B.V. and ECNP. All rights reserved.)

The progressive and rapid aging of population is the demographic characteristic in the Western countries. This rapid process of aging is causing an increasing burden on the social and health-care services. In this context, the precise knowledge of the environmental, socio-economical and clinical characteristics of the elderly population is mandatory to find the correct strategies to achieve the successful aging. Our study aimed to investigate the functional and clinical characteristics of the elderly (aged 60 to 85 years) of San Teodoro (1500 inhabitants), a rural village of Central Sicily, in particularly considering the dementia prevalence. In 2005, all the elderly between 60 and 85 years old were invited to participate to the study. The list of the potential participants was obtained from the Registry office of the municipality. The final number of the eligible subjects was 374. Rate of participation was 74.9% (280 subjects, 120 M and 160 F). The study was conducted door-to-door. Dementia prevalence was 7.1% (20 subjects, 8 M and 12 F), with 60% Alzheimer's disease and 15% vascular dementia, slightly higher than that of the European countries (6%). The high prevalence of hypertension (80.3%) and the low education level, two important risk factors for dementia, could explain in part the difference observed.

The cell division cycle 2 (CDC2) gene is a candidate susceptibility gene for Alzheimer's disease (AD). We investigated the CDC2 genotype, and allele and haplotype frequencies in AD patients and matched controls, distinguishing between apolipoprotein E (APOE) epsilon4 allele carriers and non-carriers. APOE epsilon4 is an established predictor of AD risk. APOE and CDC2 genotypes were examined in 109 sporadic AD patients and in 110 healthy age- and sex-matched controls from Sicily. The epsilon4 allele of APOE was predictive of AD risk in our study group (odds ratio: 5.37, 95% CI 2.77-10.41; P<0.0001). Genotype and allele frequencies of the three tested CDC2 polymorphisms (Ex6+7I/D, Ex7-15 G>A, Ex7-14 T>A) were not significantly different between AD patients and controls. However, a significant different distribution of a specific CDC2 haplotype (I-G-T) was found between AD patients and controls when analyzing APOE epsilon4-positive subjects (P=0.0288). Moreover, the combined presence of the I-G-T haplotype and the epsilon4 allele almost doubled the risk of AD (odds ratio: 10.09, 95% CI 3.88-26.25; P<0.0001) compared to carriers of epsilon4 alone. This study suggests that the I-G-T haplotype of the CDC2 gene increases the risk of AD in APOE epsilon4 carriers.

Background: In the central nervous system, several neuropeptides are believed to be involved in the pathophysiology of Alzheimer's disease (AD). Indeed, previous studies have documented that glucagon-like peptide 1 (GLP-1) possesses neurotropic properties and can reduce amyloid-beta peptide levels in the brain in vivo. Moreover, the concentrations of neuropeptide Y (NPY) seem to be altered in the cerebrospinal fluid of patients with AD and in subjects with major depression. Finally, among the modifications induced by aging, a dysregulation of the ghrelin-growth hormone (GH) system has been reported., Methods: We investigated the plasma concentrations of these neuropeptides in 14 subjects with AD. Data obtained from these patients were compared with data from an age- and weight-matched healthy group., Results: No significant differences were found between the two groups in relation to plasma levels of GLP-1, NPY, ghrelin and GH. Peripheral NPY concentrations were positively correlated with ghrelin levels in both groups, and with plasma GLP-1 concentration only in controls., Conclusion: On the basis of our results, peripheral levels of these neuropeptides seem not to serve as biochemical markers of AD.

The genotype of apolipoprotein E was examined in 173 sporadic Alzheimer's disease (AD) patients, 132 with late onset (LOAD) and 41 with early onset (EOAD), and in 174 healthy matched controls from Sicily. Despite a low frequency of the epsilon 4 allele (6.3%, 95% CI: 4.2--9.4) in controls, epsilon 4 allele was a stronger predictor of AD risk (odds ratio: 5.8, 95% CI: 3.5--9.4; p<0.0001) than in most of the studies performed in other regions of Italy, and it has no influence on age at onset. epsilon 4/epsilon 4 and epsilon 4/epsilon 3 genotypes were similar predictors of AD risk. Conversely, a decreased risk was found in epsilon 3 allele carriers (odds ratio: 0.3, 95% CI: 0.2--0.4; p<0.0001), which remained significant when considering EOAD cases only (odds ratio: 0.2, 95% CI: 0.1--0.4, p<0.0001). In conclusion, differences in association strength of epsilon 4 allele with AD between Sicily and other regions of Italy suggest an influence of complex gene-gene and gene-environment interactions.

Background: Genetic polymorphisms of APO-E, homocysteine, and the IL-1 gene cluster (IL-1A, IL-1B, receptor antagonist IL-1RN) are associated with sporadic Alzheimer's disease and may involve interdependent pathways of neuronal toxicity., Objective: To determine whether these polymorphisms and the genetic determinants of homocysteine (methylenetetrahydrofolate reductase, MTHFR; methionine synthase, MTR; transcobalamin, TC) are associated with an increased risk of severe dementia in Alzheimer's disease., Methods: 152 patients with Alzheimer's disease and 136 controls were studied. The association of occurrence and dementia severity (Reisberg score <6 and >or=6) of Alzheimer's disease with APO-E, IL-1A, IL-1B, IL-1RN, MTHFR677 C-->T and 1298A-->C, MTR 2756 A-->G, and TC 776 C-->G polymorphisms was evaluated by multivariate logistic regression analysis after adjustment for age, sex, and age of onset of Alzheimer's disease., Results: IL-1A TT and IL-1B CT/TT associated genotypes were at risk of Alzheimer's disease (odds ratio 4.80 (95% confidence interval, 1.32 to 17.40), p = 0.017); the MTR 2756 AA genotype was at risk of severe dementia (OR 2.97 (1.23 to 7.21), p = 0.016); IL-1 RN*2 was protective (OR 0.28, (0.11 to 0.69), p = 0.006). Allele epsilon4 of the APO-E and IL-1B CC genotypes increased the risk of severe Alzheimer's disease associated with the MTR 2756 AA genotype by 3.3-fold and 1.5-fold, respectively., Conclusions: Distinct determinants of the IL-1 gene cluster are related to the generation and progression of Alzheimer's disease. MTR only influences progression of the disease, which may be enhanced by carriage of allele epsilon4 of APO-E.

Objective: Neurosteroids have been suggested to be involved in the regulation of cognitive performances. A major neurosteroid gamma-aminobutyric acid (GABA) agonist is allopregnanolone: the main source of circulating allopregnanolone is the adrenal cortex. Studies indicated that a disturbance of the central regulation of the hypothalamic-pituitary-adrenocortical axis occurs in both senile (Alzheimer's disease: AD) and vascular dementia (VD)., Design: The aim of the present study was to evaluate the levels of circulating allopregnanolone, dehydroepiandrosterone (DHEA) and cortisol and their response to corticotropin-releasing factor (CRF) test in AD and VD., Methods: Three groups of 12 subjects were included in the study: AD, VD and age-matched control subjects. CRF test was performed in all subjects and allopregnanolone, DHEA and cortisol levels were measured every 15min for 2h., Results: Mean +/- s.e.m. allopregnanolone and DHEA basal levels were significantly lower in AD and VD than in controls, while cortisol levels were significantly higher than in controls (P<0.01). Allopregnanolone and DHEA levels increase in response to CRF test in all subjects but the area under curve (AUC) in patients was significantly lower than in controls (P<0.01). Cortisol secretion appeared to be very sensitive in response to CRF stimulation: in fact, cortisol response to CRF test in AD and VD subjects was higher (both as AUC and as % max increase) than in controls (P<0.01)., Conclusions: The present study firstly showed that allopregnanolone levels are reduced both in AD and in VD and that dementia has a preserved stimulated response of allopregnanolone to CRF. Overall, however, the total response of allopregnanolone to CRF remains reduced in respect to controls. Further studies are necessary for a better understanding of the role of neurosteroids in the regulation of cognitive function.