APOE ε2 and ε4 influence the susceptibility for Alzheimer's disease but not other dementias.

Apolipoprotein E (APOE) genotype was determined in a population of patients with dementia, including 735 patients with Alzheimer's disease (AD), 75 with Frontotemporal Lobar Degeneration (FTLD), 97 with Vascular Dementia (VaD) and 40 with Lewy Body Dementia (LBD), as well as in 506 age- and gender-matched controls (CON). APOE ε2 allele frequency was lower in patients with AD (2.8%) than in CON (6.4%, P≤0.001, OR: 0.41). Similar results were obtained comparing AD with FTLD (6.7%, P≤0.01, OR: 0.37), at difference from VaD (5.6%, P>0.05) or LBD (5.0%, P>0.05). The frequency of the APOE ε4 allele was increased in patients with AD (25.1%) as compared with CON (8.2%, P≤0.001, OR: 4.24), FTLD (11.3%, P≤0.001, OR: 2.67), VaD (11.8%, P≤0.001, OR: 3.02), or LBD (13.8%, P=0.048, OR: 2.07). The frequency of the ε4/ε4 genotype was increased in AD patients compared with controls (6.3 versus 0.8%, P≤0.001, OR: 8.38). The presence of the ε2 allele is a protective factor for AD, whereas the ε4 allele acts as a risk factor for the disease. Both alleles do not influence the susceptibility to FTLD, LBD and VaD.

Progranulin plasma levels as potential biomarker for the identification of GRN deletion carriers. A case with atypical onset as clinical amnestic Mild Cognitive Impairment converted to Alzheimer's disease.

Progranulin (GRN) mutations are associated with different clinical phenotypes, including Frontotemporal Lobar Degeneration (FTLD), Corticobasal Degeneration and Alzheimer's disease (AD). In addition, the range of age at onset is very wide and patients presenting initial symptoms around eighty years have been described. Previous studies demonstrated that progranulin plasma levels determination may be a reliable method to identify GRN deletion carriers. We thus evaluated progranulin plasma levels in all patients followed at our Alzheimer's Centre whose plasma was available (n=176) and found four patients displaying low values. Three of them carried the CACT deletion in exon 7 and their clinical diagnosis was behavioral variant Frontotemporal Dementia. We also identified a patient carrying a previously reported CAGT deletion in exon 5. Here, we report on this case. The onset of symptoms was at 77 years and the initial diagnosis was of amnestic Mild Cognitive Impairment (aMCI), which converted to AD six months later. In the following years, the patient also developed behavioral disturbances, gait apraxia and parkinsonian symptoms. At present, she is 84 years old and is still followed-up periodically. This case confirms progranulin plasma levels as a reliable biomarker to identify GRN deletion carriers and discriminate between FTLD and other dementias which may mimic it. We thus encourage the inclusion of this non-invasive and easy test in clinical practice.

Intrathecal levels of IL-6, IL-11 and LIF in Alzheimer's disease and frontotemporal lobar degeneration.

Cerebrospinal fluid (CSF) levels of interleukin (IL)-6, IL-11 and leukaemia inhibitory factor (LIF) were evaluated in 43 patients with Alzheimer's disease (AD) and 24 patients with frontotemporal lobar degeneration (FTLD) as compared with 30 agematched controls (CON), and correlated with clinical and demographic data and with CSF biomarkers amyloid beta (A beta)42, total tau and tau phosphorylated at position 181 (P-tau). CSF IL-11 mean levels were significantly increased in AD and FTLD as compared with CON (6.5 +/- 4.6 and 6.6 +/- 5.1 versus 3.1 +/- 3.3 pg/ml, P = 0.009). IL-6 mean levels did not differ between patients and CON (P > 0.05),whereas LIF levels were not detectable in patients or in CON. In AD patients, a significantly positive correlation between MMSE scores and IL-11 CSF concentration was observed (r = 0.344, P = 0.028). No correlations with CSF A beta 42, total tau and P-tau were found. IL-11, but not IL-6 levels are increased in AD and FTLD, and the highest peaks were observed in patients with a less severe degree of cognitive deterioration, therefore suggesting a role of this cytokine in early phases of neurodegeneration.

Association of a NOS1 promoter repeat with Alzheimer's disease.

The gene encoding NOS-I (NOS1) displays a complex transcriptional regulation, with nine alternative first exons. Exon 1c and 1f are the most abundant forms in the brain. A functional single nucleotide polymorphism (SNP) in exon 1c and a polymorphism in exon 1f, consisting of a variable number of tandem repeats (VNTR) originating short (S) and long (L) alleles, were studied in 184 patients with Alzheimer's disease (AD) and 144 gender- and age-matched controls. No differences were found for the Ex1c G-84A. The Ex1f-VNTR S allele was significantly more common in AD (55% versus 44%, P=0.009, OR=1.52) as was the S/S genotype (28% versus 14%, P=0.008; OR=2.37). The S allele showed a highly significant interaction with the ApoE epsilon 4 allele (OR: 10.83). Therefore, short alleles of the NOS1 exon 1f-VNTR are likely to be susceptibility factors for AD, and interact with the epsilon 4 allele to markedly increase the AD risk.

Candidate gene analysis of IP-10 gene in patients with Alzheimer's disease.

Interferon-gamma-inducible Protein-10 (IP-10) is supposed to play a role in Alzheimer's disease (AD) development, as demonstrated by increased levels in cerebrospinal fluid from patients with AD. A mutation scanning of IP-10 exonic region was carried out in 10 patients with AD and 10 age-matched controls, demonstrating the presence of two previously reported single nucleotide polymorphisms (SNPs) in exon 4 (G-->C and T-->C) as well as a novel SNP in exon 2 (C-->T). Exon 4 G-->C and T-->C allelic variants were next evaluated in a population of 279 AD patients and 251 controls, in order to determine whether their presence could influence the susceptibility towards the development of the disease. These two SNPs were in complete linkage disequilibrium. No differences in haplotype frequencies were found in AD patients as compared with controls, even stratifying according to the presence of Apolipoprotein E varepsilon4 allele, gender or age at onset. A new protocol was developed to easily determine the C-->T SNP in exon 2. A preliminary analysis revealed a very low frequency of this allelic variant (1%). Therefore, the complete association study was not carried out because the size of our population was not sufficient to draw reliable conclusions. According to these results, IP-10 does not seem to be a risk factor for AD. However, a novel rare polymorphism has been identified, which could exert a role in AD susceptibility. Thus, further studies on larger populations are needed before confidently excluding IP-10 as a susceptibility gene for AD.

Intrathecal chemokine synthesis in mild cognitive impairment and Alzheimer disease.

BACKGROUND: Immunoreactivity for several chemokines and for their related receptors has been demonstrated in resident cells of the central nervous system, and the up-regulation of some of them is associated with pathological changes found in Alzheimer disease (AD). OBJECTIVE: To determine interferon-gamma-inducible protein 10 (IP-10), monocyte chemotactic protein 1 (MCP-1), and interleukin 8 (IL-8) levels in cerebrospinal fluid (CSF) from subjects with amnestic mild cognitive impairment (MCI) and patients with AD as compared with age-matched controls. PATIENTS: Thirty-eight subjects with amnestic MCI, 36 patients with AD, and 41 age-matched subjects with noninflammatory affections of the nervous system. DESIGN: Evaluation of CSF chemokine production at time of diagnosis of MCI and AD; correlation with clinical and personal data. Longitudinal evaluation of subjects with MCI until conversion to AD. RESULTS: Cerebrospinal fluid IP-10 concentration was significantly increased in patients with MCI and mild AD but not in patients with severe AD (Mini-Mental State Examination score <15), whereas MCP-1 and IL-8 levels were increased in patients with MCI and all patients with AD. A significant positive correlation between Mini-Mental State Examination score and CSF IP-10 or MCP-1 concentration was observed in patients with AD. No correlation between IP-10 levels and age was found, whereas MCP-1 and IL-8 levels correlated positively with age. Out of 38 subjects with MCI, 19 developed AD within a 1- to 3-year follow-up. CONCLUSIONS: The presence of inflammatory molecules is likely to be a very early event in AD pathogenesis, even preceding the clinical onset of the disease, as demonstrated by subjects with MCI who developed AD over time. Interferon-gamma-inducible protein 10 is specifically increased in MCI and seems to decrease with the progression of AD, whereas MCP-1 and IL-8 are up-regulated also in late stages of the disease, suggesting a role in phases in which neurodegeneration is prevalent.

Oxidative imbalance in patients with mild cognitive impairment and Alzheimer's disease.

Increasing evidence supports a role of oxidative imbalance, characterized by impaired antioxidant enzymatic activity and increased reactive oxygen species (ROS) production, in mild cognitive impairment (MCI) and Alzheimer's disease (AD) pathogenesis. Hyperhomocysteinemia, another risk factor for AD, also contributes to oxidative damage. Plasma total homocysteine (tHcy) and ROS levels, and total antioxidant capacity (TAC) were determined in 71 AD, 36 MCI and 28 vascular dementia (VaD) patients as well as in 44 age-matched controls. tHcy levels were significantly increased in patients with AD and VaD an a trend towards an increase in multiple domain MCI was observed. TAC was significantly decreased in AD as well as MCI, but not in VaD patients. In AD patients, a negative correlation was found between TAC and disease duration. ROS levels did not differ among groups, but were correlated with age. In conclusion, a pattern characterized by increased tHcy levels and decreased TAC is present in AD as well as MCI patients. While increased tHcy levels were also found in VaD, TAC modifications occur specifically in AD. ROS levels appear to be correlated with age rather than with a specific dementing disorder, thus leading to the hypothesis that oxidative imbalance observed in AD could be due to a decreased TAC.

Serum MCP-1 levels are increased in mild cognitive impairment and mild Alzheimer's disease.

Upregulation of a number of chemokines, including monocyte chemotactic protein-1 (MCP-1), is associated with Alzheimer's disease (AD) pathological changes. Emerging evidence suggests that inflammatory events precede the clinical development of AD, as cytokine disregulation has been observed also in patients with mild cognitive impairment (MCI). MCP-1 levels were evaluated in serum samples from 48 subjects with MCI, 94 AD patients and 24 age-matched controls. Significantly increased MCP-1 levels were found in MCI and mild AD, but not in severe AD patients as compared with controls. mRNA levels in peripheral blood mononuclear cells (PBMC), evaluated by quantitative RT-PCR analysis, paralleled serum MCP-1 levels. Moreover, a progressive MCP-1 decrease was observed over a 1-year follow up in a subgroup of MCI subjects converted to AD. MCP-1 upregulation is likely to be a very early event in AD pathogenesis, by far preceding the clinical onset of the disease. Nevertheless, as MCP-1 is likely to play a role in several pathologies with an inflammatory component, a possible usefulness as an early AD biomarker would be possible only in combination with other molecules.

Progressive, isolated language disturbance: its significance in a 65-year-old-man. A case report with implications for treatment and review of literature.

Language disturbances are common features occurring in different neurodegenerative diseases, including Alzheimer's disease (AD) and the Frontotemporal Lobar Degeneration (FTLD) variants Primary Progressive Aphasia (PPA) and Semantic Dementia (SD). Despite AD and FTLD are supposed to have a different pathophysiology, PPA has been demonstrated to have in some cases an AD pathological component. The syndromic and etiological heterogeneity is crucial for the differential diagnosis and consequently for a therapeutical approach. Here, the case of a patient with progressive isolated language disturbances is presented, and further discussed on the basis of current diagnostic criteria and available guidelines for treatment.

Influence of the Glu298Asp polymorphism of NOS3 on age at onset and homocysteine levels in AD patients.

The distribution of the Glu298Asp polymorphism in NOS3 gene was determined in 405 Italian patients with "probable" Alzheimer's disease (AD) compared with 253 age-matched controls. Total plasma homocysteine (tHcy) levels were evaluated in 97 patients and 23 controls, and were correlated with the Glu298Asp genotype. A significantly increased frequency of the Glu/Glu genotype in late onset AD (LOAD) patients was found. tHcy levels were significantly increased in patients compared with controls and, notably, higher in LOAD than in early onset AD (EOAD). Stratifying by the Glu298Asp genotype, a trend toward an increase of tHcy was present in Glu/Glu homozygous. This wild type genotype seems to be associated with LOAD. tHcy levels are significantly increased in AD compared with controls and, moreover, higher in LOAD than in EOAD, possibly in correlation with the microvascular disease occurring with aging. Besides, a contribution of the Glu/Glu genotype in increasing tHcy levels has been observed.

CCR2-64I polymorphism and CCR5Delta32 deletion in patients with Alzheimer's disease.

Monocyte chemoattractant protein-1 (MCP-1) and RANTES, as well as their related receptors, have been shown to be involved in Alzheimer's disease (AD) pathogenesis. Genes for their related receptors, CCR2 and CCR5, respectively, are characterized by the presence of two polymorphisms: a conservative change of a valine with an isoleucine at codon 64 of CCR2 (CCR2-64I) and a 32-bp deletion in the coding region of CCR5 (CCR5Delta32), which leads to the expression of a nonfunctional receptor. The distribution of the CCR2-64I and CCR5Delta32 polymorphisms was determined in 290 AD patients and in 222 controls. A decreased frequency and an absence of homozygous for the polymorphism CCR2-64I were found, thus suggesting a protective effect of the mutated allele on the occurrence of AD. However, these findings must be cautiously interpreted as the overall significance was found without adjustment for multiple comparisons and is coming from the complete absence of the genotype 64I/64I in AD patients. Conversely, no different distribution of the CCR5Delta32 deletion in the two populations was shown. Stratifying by the presence of ApoE varepsilon4 allele, gender or age at onset, no differences in either allele frequencies were observed.

MCP-1 in Alzheimer's disease patients: A-2518G polymorphism and serum levels.

MCP-1 levels are increased in CSF of patients with Alzheimer's disease (AD) compared with controls, suggesting a role in the development of dementia. Recently, a biallelic A/G polymorphism in the MCP-1 promoter at position -2518 has been found, influencing the level of MCP-1 expression in response to an inflammatory stimulus. The distribution of the A-2518G SNP was determined in 269 AD patients and in 203 healthy age matched controls, showing no differences between the two groups. On the contrary, a significant increase of MCP-1 serum levels in AD patients carrying at least one G mutated allele was observed. Moreover, the highest peaks of MCP-1 serum levels were present in patients carrying two G alleles. Stratifying by ApoE genotype, gender or age at onset, no differences in both allele frequency and MCP-1 serum concentration were observed. The A-2518G polymorphism in MCP-1 gene does not seem to be a risk factor for the development of AD, but its presence correlates with higher levels of serum MCP-1, which can contribute to increase the inflammatory process occurring in AD.