Elena Sinforiani

A randomized controlled study on effects of ibuprofen on cognitive progression of Alzheimer’s disease

Background and aims: Epidemiological studies have examined the association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of Alzheimer’s disease (AD). Recently, a variety of experimental studies indicates that a subset of NSAIDs, such as ibuprofen or flurbiprofen, also have Aβ-lowering properties in both AD transgenic mice and cell cultures of peripheral, glial and neuronal origin. In this trial, we evaluated whether the non-selective NSAID ibuprofen slows disease progression in patients with mild to moderate AD. Methods: This was a 12-month multicenter, randomized, double-blind, placebo-controlled, parallel group trial. Participants with mild-moderate AD (Mini-Mental State Examination score >15, <26; Clinical Dementia Rating= 0.5–1), 65 years or older, with reliable caregivers, were recruited between April 2003 and September 2004. Seven AD Outpatient Treatment Centers screened 530 patients, 132 of whom were enrolled. Interventionconsisted of 400 mg ibuprofen twice a day or placebo, together with 20 mg once a day of esomeprazol, or placebo. The primary measure was any one-year change in the Alzheimer Disease Assessment Scale-Cognitive (ADAS-Cog) subscale score. Secondary measures included changes in MMSE, CDR, Basic and Instrumental Activities of Daily Living scales, and Neuropsychiatry Inventory (NPI). Results: Fifty-one patients (77%) in the ibuprofen vs 46 (70%) in the placebo group completed the protocol (p>0.20). In intention-to-treat analysis, ADAS-Cog score worsening was similar in the two groups (p=0.951, treatment difference= 0.1, CI-2.7; 2.9). No differences were found for any secondary outcomes. In a subsample of genotyped patients, ApoE ε4 carriers treated with ibuprofen (n=27) were the only group without significant cognitive decline. Conclusions: Ibuprofen, if used for relatively short periods of time and although well tolerated thanks to gastroprotection, does not seem to be effective in tertiary prevention of mild-moderate AD. Our results suggest the need to examine whether differences in the response to NSAIDs exist, based on ApoE ε4 carrier status.

Conformationally altered p53 : a novel Alzheimer's disease marker?

The identification of biological markers of Alzheimers disease (AD) can be extremely useful to improve diagnostic accuracy and/or to monitor the efficacy of putative therapies. In this regard, peripheral cells may be of great importance, because of their easy accessibility. After subjects were grouped according to diagnosis, the expression of conformationally mutant p53 in blood cells was compared by immunoprecipitation or by a cytofluorimetric assay. In total, 104 patients with AD, 92 age-matched controls, 15 patients with Parkinsons disease and 9 with other types of dementia were analyzed. Two independent methods to evaluate the differential expression of a conformational mutant p53 were developed. Mononuclear cells were analyzed by immunoprecipitation or by flow-cytometric analysis, following incubation with a conformation-specific p53 antibody, which discriminates unfolded p53 tertiary structure. Mononuclear cells from AD patients express a higher amount of mutant-like p53 compared to non-AD subjects, thus supporting the study of conformational mutant p53 as a new putative marker to discriminate AD from non-AD patients. We also observed a strong positive correlation between the expression of p53 and the age of patients. The expression of p53 was independent from the length of illness and from the Mini Mental State Examination value.

Age-related decline in RACK-1 expression in human leukocytes is correlated to plasma levels of dehydroepiandrosterone

Aging is associated with remodeling of the immune system, contributing to increased incidence of infections, autoimmune diseases, and cancer among the elderly. Alterations in several signal transduction pathways have been reported to play an important role in immunosenescence. We show that peripheral blood leukocytes obtained from old donors (≥65 years) have a significantly reduced expression of receptor for activated C kinase 1 (RACK‐1), a protein required for protein kinase C (PKC)‐β signaling, as compared with young donors (≤40 years), both in males and females. The decline in RACK‐1 immunoboth in reactivity was age‐related (Spearman correlation, r=–0.278, P=0.012). All leukocyte subpopulations, namely lympho‐monocytes, granulocytes, and B and T cells, showed a similar defect. We also observed a direct correlation between circulating dehydroepiandrosterone (DHEA) and RACK‐1 expression in leukocytes (Spearman correlation, r=0.388, P=0.001). Furthermore, in vitro treatment with DHEA resulted in increased RACK‐1 expression in leukocytes and lymphocyte proliferation, confirming the role of this hormone in the modulation of its expression and immune functions. A relevant consequence of RACK‐1‐reduced expression was the observation that release of tumor necrosis factor α following lipopolysaccharide challenge and mitogen‐induced lymphocye proliferation, which involves PKC‐β activation, was significantly reduced in elderly subjects. Overall, our findings contribute to the understanding of the complex process of immunosenescence and identify age‐related loss in immunological responses as partially associated with decreased RACK‐1 expression.

Influence of COMT Val158Met Polymorphism on Alzheimer's Disease and Mild Cognitive Impairment in Italian Patients

COMT (Catechol-O methyltransferase) gene is one of the key players in synaptic plasticity and in learning and memory mechanisms. A single nucleotide polymorphism (rs4680; G to A) in the COMT coding region causes Val158Met aminoacid substitution in the corresponding protein, with Val allele exhibiting a 3- to 4-fold increase in enzyme activity compared to Met. With the purpose of examining the influence of COMT as a genetic risk factor for cognitive impairment, we analyzed a sample of 248 healthy subjects, 276 patients affected by Alzheimers disease (AD), and 70 subjects with mild cognitive impairment (MCI), the latter condition possibly representing a prodrome for dementia. All subjects were analyzed for COMT rs4680 polymorphism and APOE genotype. Our study strengthens data showing that APOE ε4 allele is an independent risk factor for AD and also a risk factor for MCI. Neither COMT alleles nor genotypes proved to be independently associated with the risk of AD or MCI in our sample. However, we found an association between COMT GG genotype (Val/Val) and APOE ε4 carrier status and the risk of AD and MCI. In particular, when GG genotype is included into the multinomial analysis, the risk of AD and MCI due to APOE ε4 allele is increased of about 2-3 fold; moreover, the risk conferred by the combination of G and ε4 alleles is more pronounced in male patients. To our knowledge, this synergistic effect is here shown for the first time on a population sample representative of Caucasian patients.

Pharmacogenetics and Pharmagenomics, Trends in Normal and Pathological Aging Studies: Focus on p53

In spite of the fact that the aging organism is the result of complex life-long gene/environment interactions, making peculiar the susceptibility to diseases and the response to drugs, pharmacogenetics studies are largely neglected in the aged. Altered response to drugs, cardiovascular and metabolic alterations, cancer and dementia are among the age associated ailments. The latter two are the major contributors to illness burden for the aged. Aging, dementia and cancer share a critical set of altered cellular functions in the response to DNA damage, genotoxic stress, and other insults. Aging in higher animals may be influenced by the balance of cell survival versus death, a decision often governed by checkpoint proteins in dividing cells. The paper is mainly focused on one of such proteins, p53 which has been recently shown to be involved in aging and Alzheimers Disease (AD). Within this reference frame we studied p53 in aged controls and demented patients finding that with aging there is an increase of mutant like conformation state of p53 in peripheral blood cells, which is more pronounced in AD patients. As a result of such conformational change, p53 partially loses its activity and may become unable to properly activate an apoptotic program when cells are exposed to a noxious stimulus. Moreover we found that the tertiary structure of p53 and the sensitivity to p53-dependent apoptosis are affected by low concentrations of soluble beta amyloid, the peptide that accumulates in AD brain but also present in peripheral tissues. It is possible that p53 conformers may occur in the presence of misfolded molecules such as, but not limited to, beta amyloid. In particular at neuronal level the altered function of cell cycle proteins may affect synaptic plasticity rather than cell duplication.

Brain-Derived Neurotrophic Factor Gene Variants and Alzheimer Disease: An Association Study in an Alzheimer Disease Italian Population

Brain-derived neurotrophic factor (BDNF) promotes neuronal survival during development and protects neurons from insults of various kinds. Changes in production of BDNF have been reported in differing neurodegenerative pathologies and, in particular, in Alzheimer disease (AD). We studied 200 AD patients and 408 healthy controls for BDNF Val66Met(G196A) polymorphism, 200AD and 384 healthy controls for BDNF 270 C/T polymorphism, and 200AD and 393 healthy controls for BDNF 11757 G/C polymorphism by restriction fragment length polymorphism (RFLP) and real-time PCR. Our results indicated that the 11757 G/C BDNF polymorphism was significantly associated with AD. A statistically significant increase of GG genotype frequency in AD versus healthy subjects (p=0.0331) was observed, whereas the CG genotype demonstrates a statistically significant decrease of frequency in AD patients versus controls (p=0.0194). We focused our attention on haplotype reconstruction: A statistically significant decrease of the TAC haplotype frequency in AD patients versus healthy controls group (p=0.005) and a statistically significant increase of the CAC haplotype frequency in patients versus control (p=0.019) was demonstrated. We then studied the haplotype frequencies dividing patients according to gender. A statistically significant increase of the CAC haplotype in the male AD group compared with male healthy controls (p=0.041) was found, whereas a statistically significant decrease of TAC haplotype frequency in AD females versus healthy females (p=0.005) and a statistically significant increase of CAC haplotype frequency in female patients versus healthy females (p=0.019) was noticed. We propose that these haplotypes could be a further effective marker for AD.

RACK-1 expression and cytokine production in leukocytes obtained from AD patients

Background and aims: The purpose of this study was to evaluate in vitro cytokine production in blood leukocytes obtained from sporadic AD patients, aged controls and young individuals. Methods: Diluted whole blood was treated in the presence or absence of LPS (1 μg/mL) for varying times (3–48 h). The release of IL-8, IL-10 and TNF-α in conditioned media was evaluated by commercially available sandwich ELISA. Results: Data obtained are indicative of the presence of an unregulated systemic inflammation in AD patients. Leukocytes obtained from AD patients had increased spontaneous TNF-α release and decreased LPS-induced IL-10 production, in comparison with both old controls and young subjects, while identical IL-8 production was observed in all groups. The last finding indicates that there was no shift in the potency or efficacy of the response towards LPS with aging, but alterations in downstream signal transduction pathways are probably altered with aging and pathological conditions. Conclusions: The dysregulation of cytokine production observed in AD patients may partially be explained by a significant reduction in the expression of RACK-1, a protein crucial for integration of signaling pathways with different physiological functions, such as cytokine production.

The Italian Alzheimer's Disease Neuroimaging Initiative (I-ADNI): Validation of Structural MR Imaging

BACKGROUND The North American Alzheimers Disease Neuroimaging Initiative (NA-ADNI) was the first program to develop standardized procedures for Alzheimers disease (AD) imaging biomarker collection. OBJECTIVE We describe the validation of acquisition and processing of structural magnetic resonance imaging (MRI) in different Italian academic AD clinics following NA-ADNI procedures. METHODS 373 patients with subjective memory impairment (n = 12), mild cognitive impairment (n = 92), Alzheimers dementia (n = 253), and frontotemporal dementia (n = 16) were enrolled in 9 Italian centers. 22 cognitively healthy elderly controls were also included. MRI site qualification and MP-RAGE quality assessment was applied following the NA-ADNI procedures. Indices of validity were: (i) NA-ADNI phantoms signal-to-noise and contrast-to-noise ratio, (ii) proportion of images passing quality control, (iii) comparability of automated intracranial volume (ICV) estimates across scanners, and (iv) known-group validity of manual hippocampal volumetry. RESULTS Results on Phantom and Volunteers scans showed that I-ADNI acquisition parameters were comparable with those one of the ranked-A ADNI scans. Eighty-seven percent of I-ADNI MPRAGE images were ranked of high quality in comparison of 69% of NA-ADNI. ICV showed homogeneous variances across scanners except for Siemens scanners at 3.0 Tesla (p = 0.039). A significant difference in hippocampal volume was found between AD and controls on 1.5 Tesla scans (p < 0.001), confirming known group validity test. CONCLUSION This study has provided standardization of MRI acquisition and imaging marker collection across different Italian clinical units and equipment. This is a mandatory step to the implementation of imaging biomarkers in clinical routine for early and differential diagnosis.

P2-407: Effects of ibuprofen on Alzheimer’s disease cognitive progression: A randomized controlled trial

(Alzheimer’s Disease Assessment Scale cognitive subscale, or Severe Impairment Battery; ADAS-cog or SIB), and function (Alzheimer’s Disease Cooperative Study Activities of Daily Living 19or 23-item scale; ADCS-ADL19/23) were investigated. Safety was analysed via the incidence rates of adverse events. Results: Memantine was statistically significantly superior to placebo in all three efficacy domains. Standardized mean differences between memantine and placebo were as follows (OC analysis) global status (0.22; p 0.001), cognition (0.26; p 0.001), and function (0.18; p 0.001). LOCF analysis showed similar results. The analysis of AE rates confirmed that memantine is safe and well tolerated, with an overall incidence of adverse events that was comparable to placebo. Conclusions: In patients with moderate to severe AD, memantine offers significant benefits over placebo in the three clinically most relevant domains of global status, cognition, and function. The current meta-analysis supports the use of memantine across this range of disease stages, highlighting a clinically relevant efficacy and favourable safety profile.

Searching for predictive blood biomarkers: misfolded p53 in mild cognitive impairment.

The identification and validation of biomarkers for preclinical patients with mild cognitive impairment (MCI) at-risk for Alzheimers disease (AD) development is increasingly important. We used the cytofluorimetric analysis of unfolded p53 to determine the prognostic ability of the protein as predictive signature from MCI to AD in a longitudinal study of a population of presymptomatic patients with the clinical diagnosis of MCI. Venous blood samples from 24 healthy subjects, 28 MCI and 15 AD were analyzed with the cytofluorimetric method for unfolded p53 protein detection. Twenty-four MCI patients had clinical follow-up subsequent to the analysis for unfolded p53. Elevated levels of the conformationally altered protein were able to discriminate both MCI and AD patients comparing with healthy subjects. Longitudinal follow-up revealed that 7/24 MCI patients progressed to AD. All converters (100%) were predicted by elevated levels of unfolded p53, with a positive predictive value of 87.5%. These data support and extend our previous observation that the cytofluorimetric approach for unfolded p53 protein was able to discriminate AD patients from healthy subjects and to predict the progression from MCI to AD in presymptomatic patients before clinical diagnosis for AD was evident.