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17β-estradiol,the most biologically active estrogen, exerts wide-ranging effects in brain through its action on estrogen receptors (ERs), influencing higher-order cognitive function and neurobiological aging. However, our knowledge of ER expression and regulation by neuroendocrine aging in the living human brain is limited. This in vivo multi-modality neuroimaging study of healthy midlife women reveals progressively higher ER density over the menopause transition in estrogen-regulated networks. Effects were independent of age and plasma estradiol levels, and were highly consistent, correctly classifying all women as being post-menopausal or not. Higher ER density was generally associated with lower gray matter volume and blood flow, and with higher mitochondria ATP production, possibly reflecting compensatory mechanisms. Additionally, ER density predicted changes in thermoregulation, mood, cognition, and libido. Our data provide evidence that ER density impacts brainstructure, perfusion and energy production during female endocrine aging, with clinical implications for women’s health.

BACKGROUND Alzheimer's disease (AD) diagnosis can be hindered by amyloid biomarkers discordances. OBJECTIVE We aim to interpret discordances between amyloid positron emission tomography (Amy-PET) and cerebrospinal fluid (CSF) (Aβ42 and Aβ42/40), using Amy-PET semiquantitative analysis, [18F]fluorodeoxyglucose (FDG)-PET pattern, and CSF assays. METHOD Thirty-six subjects with dementia or mild cognitive impairment, assessed by neuropsychological tests, structural and functional imaging, and CSF assays (Aβ42, Aβ42/40, p-tau, t-tau), were retrospectively examined. Amy-PET and FDG-PET scans were analyzed by visual assessment and voxel-based analysis. SUVR were calculated on Amy-PET scans. RESULTS Groups were defined basing on the agreement among CSF Aβ42 (A), CSF Aβ42/40 Ratio (R), and Amy-PET (P) dichotomic results ( ±). In discordant groups, CSF assays, Amy-PET semiquantification, and FDG-PET patterns supported the diagnosis suggested by any two agreeing amyloid biomarkers. In groups with discordant CSF Aβ42, the ratio always agrees with Amy-PET results, solving both false-negative and false-positive Aβ42 results, with Aβ42 levels close to the cut-off in A + R-P- subjects. The A + R + P- group presented high amyloid deposition in relevant areas, such as precuneus, posterior cingulate cortex (PCC) and dorsolateral frontal inferior cortex at semiquantitative analysis. CONCLUSION The amyloid discordant cases could be overcome by combining CSF Aβ42, CSF ratio, and Amy-PET results. The concordance of any 2 out of the 3 biomarkers seems to reveal the remaining one as a false result. A cut-off point review could avoid CSF Aβ42 false-negative results. The regional semiquantitative Amy-PET analysis in AD areas, such as precuneus and PCC, could increase the accuracy in AD diagnosis.

Background: Discordance among amyloid biomarkers is a challenge to overcome in order to increase diagnostic accuracy in dementia. Objectives: 1) To verify that cerebrospinal fluid (CSF) Aβ42/Aβ40 ratio (AβR) better agrees with Amyloid PET (Amy-PET) results compared to CSF Aβ42; 2) to detect differences among concordant positive, concordant negative, and discordant cases, basing the concordance definition on the agreement between CSF AβR and Amy-PET results; 3) to define the suspected underlying pathology of discordant cases using in vivo biomarkers. Method: We retrospectively enrolled 39 cognitively impaired participants in which neuropsychological tests, apolipoprotein E genotype determination, TC/MRI, FDG-PET, Amy-PET, and CSF analysis had been performed. In all cases, CSF analysis was repeated using the automated Lumipulse method. In discordant cases, FDG-PET scans were evaluated visually and using automated classifiers. Results: CSF AβR better agreed with Amy-PET compared to CSF Aβ42 (Cohen’s K 0.431 versus 0.05). Comparisons among groups did not show any difference in clinical characteristics except for age at symptoms onset that was higher in the 6 discordant cases with abnormal CSF AβR values and negative Amy-PET (CSF AβR+/AmyPET–). FDG-PET and all CSF markers (Aβ42, AβR, p-Tau, t-Tau) were suggestive of Alzheimer’s disease (AD) in 5 of these 6 cases. Conclusion: 1) CSF AβR is the CSF amyloid marker that shows the better level of agreement with Amy-PET results; 2) The use of FDG-PET and CSF-Tau markers in CSFAβR+/Amy-PET–discordant cases can support AD diagnosis; 3) Disagreement between positive CSF AβR and negative Amy-PET in symptomatic aged AD patients could be due to the variability in plaques conformation and a negative Amy-PET scan cannot be always sufficient to rule out AD.

ObjectiveTo investigate the types of errors produced in a picture naming task by patients with neurodegenerative dementia due to different etiologies and their neural correlates.MethodsThe same standardized picture naming test was administered to a consecutive sample of patients (n = 148) who had been studied with [18F] FDG-PET. The errors were analyzed in 3 categories (visual, semantic, and phonologic). The PET data were analyzed using an optimized single-subject procedure, and the statistical parametric mapping multiple regression design was used to explore the correlation between each type of error and brain hypometabolism in the whole group. Metabolic connectivity analyses were run at the group level on 7 left hemisphere cortical areas corresponding to an a priori defined naming network.ResultsSemantic errors were predominant in most patients, independent of clinical diagnosis. In the whole group analysis, visual errors correlated with hypometabolism in the right inferior occipital lobe and in the left middle occipital lobe. Semantic errors correlated with hypometabolism in the left fusiform gyrus, the inferior and middle temporal gyri, and the temporal pole. Phonologic errors were associated with hypometabolism in the left superior and middle temporal gyri. Both positive (occipital–posterior fusiform) and negative (anterior fusiform gyrus and the superior anterior temporal lobe) connectivity changes were associated with semantic errors.ConclusionsNaming errors reflect the dysfunction of separate stages of the naming process and are specific markers for different patterns of brain involvement. These correlations are not limited to primary progressive aphasia but extend to other neurodegenerative dementias.

An early differentiation between Alzheimer’s Disease (AD) and other dementias is crucial for an adequate patients’ management, albeit it may result difficult for the occurrence of “atypical presentations.” Current diagnostic criteria recognize the importance of biomarkers for AD diagnosis, but still an optimal diagnostic work-up isn’t available. Evaluate the utility and reproducibility of biomarkers and propose an “optimal” diagnostic work-up in atypical dementia. (1) a retrospective selection of “atypical dementia cases”; (2) a repetition of diagnostic assessment by two neurologists following two different diagnostic work-ups, each consisting of multiple steps; (3) a comparison between diagnostic accuracy and confidence reached at each step by both neurologists and evaluation of the inter-rater agreement. In AD, regardless of the undertaken diagnostic work-up, a significant gain in accuracy was reached by both neurologists after the second step, whereas in frontotemporal dementia (FTD), adding subsequent steps was not always sufficient to increase significantly the baseline accuracy. A relevant increment in diagnostic confidence was detectable after studying pathophysiological markers in AD, and after assessing brain metabolism in FTD. The inter-rater agreement was higher at the second step for the AD group when the pathophysiological markers were available and for the FTD group when the results of FDG-PET were accessible. In atypical cases of dementia, biomarkers significantly raise diagnostic accuracy, confidence, and agreement. This study introduces a proof of diagnostic work-up that combines imaging and CSF biomarkers and suggests distinct ways to proceed on the basis of a greater diagnostic likelihood.

ObjectiveTo examine in a 3-year brain imaging study the effects of higher vs lower adherence to a Mediterranean-style diet (MeDi) on Alzheimer disease (AD) biomarker changes (brain β-amyloid load via 11C-Pittsburgh compound B [PiB] PET and neurodegeneration via 18F-fluorodeoxyglucose [FDG] PET and structural MRI) in midlife.MethodsSeventy 30- to 60-year-old cognitively normal participants with clinical, neuropsychological, and dietary examinations and imaging biomarkers at least 2 years apart were examined. These included 34 participants with higher (MeDi+) and 36 with lower (MeDi−) MeDi adherence. Statistical parametric mapping and volumes of interest were used to compare AD biomarkers between groups at cross section and longitudinally.ResultsMeDi groups were comparable for clinical and neuropsychological measures. At baseline, compared to the MeDi+ group, the MeDi− group showed reduced FDG-PET glucose metabolism (CMRglc) and higher PiB-PET deposition in AD-affected regions (p < 0.001). Longitudinally, the MeDi−-group showed CMRglc declines and PiB increases in these regions, which were greater than those in the MeDi+ group (pinteraction < 0.001). No effects were observed on MRI. Higher MeDi adherence was estimated to provide 1.5 to 3.5 years of protection against AD.ConclusionLower MeDi adherence was associated with progressive AD biomarker abnormalities in middle-aged adults. These data support further investigation of dietary interventions for protection against brain aging and AD.

Objective:This observational multimodality brain imaging study investigates emergence of endophenotypes of late-onset Alzheimer disease (AD) risk during endocrine transition states in a cohort of clinically and cognitively normal women and age-matched men.Methods:Forty-two 40- to 60-year-old cognitively normal women (15 asymptomatic perimenopausal by age [CNT], 13 perimenopausal [PERI], and 14 postmenopausal [MENO]) and 18 age- and education-matched men were examined. All patients had volumetric MRI, 18F-fluoro-2-deoxyglucose (FDG)–PET (glucose metabolism), and Pittsburgh compound B–PET scans (β-amyloid [Aβ] deposition, a hallmark of AD pathology).Results:As expected, the MENO group was older than the PERI and CNT groups. Otherwise, groups were comparable on clinical and neuropsychological measures and APOE4 distribution. Compared to CNT women and to men, and controlling for age, PERI and MENO groups exhibited increased indicators of AD endophenotype, including hypometabolism, increased Aβ deposition, and reduced gray and white matter volumes in AD-vulnerable regions (p < 0.001). AD biomarker abnormalities were greatest in MENO, intermediate in PERI, and lowest in CNT women (p < 0.001). Aβ deposition was exacerbated in APOE4-positive MENO women relative to the other groups (p < 0.001).Conclusions:Multimodality brain imaging indicates sex differences in development of the AD endophenotype, suggesting that the preclinical AD phase is early in the female aging process and coincides with the endocrine transition of perimenopause. These data indicate that the optimal window of opportunity for therapeutic intervention in women is early in the endocrine aging process.

On the basis of a previously discovered anti-?V?3 integrin peptidomimetic (c(AmpRGD)) and the clinically approved antiangiogenic kinase inhibitor sunitinib, three novel dual conjugates were synthesized (compounds 1-3), featuring the covalent and robust linkage between these two active modules. In all conjugates, the ligand binding competence toward ?V?3 (using both isolated receptors and ?V?3-overexpressing endothelial progenitor EP cells) and the kinase inhibitory activity (toward both isolated kinases and EPCs) remained almost untouched and comparable to the activity of the single active units. Compounds 1-3 showed interesting antiangiogenesis properties in an in vitro tubulogenic assay; furthermore, dimeric-RGD conjugate 3 strongly inhibited in vivo angiogenesis in Matrigel plug assays in FVB mice. These results offer proof-of-concept of how the covalent conjugation of two angiogenesis-related small modules may result in novel and stable molecules, which impair tumor-related angiogenesis with equal or even superior ability as compared to the single modules or their simple combinations.

BACKGROUND AND PURPOSE: Stress‐related catecholamines have a role in cancer and β‐adrenoceptors; specifically, β(2)‐adrenoceptors have been identified as new targets in treating melanoma. Recently, β(3)‐adrenoceptors have shown a pleiotropic effect on melanoma micro‐environment leading to cancer progression. However, the mechanisms by which β(3)‐adrenoceptors promote this progression remain poorly understood. Catecholamines affect the immune system by modulating several factors that can alter immune cell sub‐population homeostasis. Understanding the mechanisms of cancer immune‐tolerance is one of the most intriguing challenges in modern research. This study investigates the potential role of β(3)‐adrenoceptors in immune‐tolerance regulation. EXPERIMENTAL APPROACH: A mouse model of melanoma in which syngeneic B16‐F10 cells were injected in C57BL‐6 mice was used to evaluate the effect of β‐adrenoceptor blockade on the number and activity of immune cell sub‐populations (Treg, NK, CD8, MDSC, macrophages, and neutrophils). Pharmacological and molecular approaches with β‐blockers (propranolol and SR59230A) and specific β‐adrenoceptor siRNAs targeting β(2)‐ or β(3)‐adrenoceptors were used. KEY RESULTS: Only β(3)‐, but not β(2)‐adrenoceptors, were up‐regulated under hypoxia in peripheral blood mononuclear cells and selectively expressed in immune cell sub‐populations including Treg, MDSC, and NK. SR59230A and β(3)‐adrenoceptor siRNAs increased NK and CD8 number and cytotoxicity, while they attenuated Treg and MDSC sub‐populations in the tumour mass, blood, and spleen. SR59230A and β(3)‐adrenoceptor siRNAs increased the ratio of M1/M2 macrophages and N1 granulocytes. CONCLUSIONS AND IMPLICATIONS: Our data suggest that β(3)‐adrenoceptors are involved in immune‐tolerance, which opens the way for new strategic therapies to overcome melanoma growth. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors—New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc

Fibrosis is the dramatic consequence of a dysregulated reparative process in which activated fibroblasts (myofibroblasts) and Transforming Growth Factor β1 (TGFβ1) play a central role. When exposed to TGFβ1, fibroblast and epithelial cells differentiate in myofibroblasts; in addition, endothelial cells may undergo endothelial-to-mesenchymal transition (EndoMT) and actively participate to the progression of fibrosis. Recently, the role of αv integrins, which recognize the Arg-Gly-Asp (RGD) tripeptide, in the release and signal transduction activation of TGFβ1 became evident. In this study, we present a class of triazole-derived RGD antagonists that interact with αvβ3 integrin. Above different compounds, the RGD-2 specifically interferes with integrin-dependent TGFβ1 EndoMT in Endothelial Colony-Forming Cells (ECPCs) derived from circulating Endothelial Precursor Cells (ECPCs). The RGD-2 decreases the amount of membrane-associated TGFβ1, and reduces both ALK5/TGFβ1 type I receptor expression and Smad2 phosphorylation in ECPCs. We found that RGD-2 antagonist reverts EndoMT, reducing α-smooth muscle actin (α-SMA) and vimentin expression in differentiated ECPCs. Our results outline the critical role of integrin in fibrosis progression and account for the opportunity of using integrins as target for anti-fibrotic therapeutic treatment.

Quantitative maps of cerebral metabolic rate of glucose (CMRGlu) from fluorine-18 fluorodeoxyglucose-PET are useful in brain studies, but are challenging to acquire because of technical constraints, which hinder their use in clinical routine. Aortic image-derived input functions (IDIFs) combined with Sokoloff's method were proposed as a suitable solution. However, Sokoloff's method requires the use of standard kinetic constants, which may produce biased estimates. Patlak's method would be more appropriate, but concern can arise when used with an aortic IDIF from unavailability of a complete brain curve acquired starting from injection. The aim of this study was to develop a CMRGlu quantification technique that combines Patlak's method with aortic IDIFs in a clinical setting.A simple acquisition protocol for aortic IDIF measurement was developed and applied on a sample of patients with different degrees of hypometabolism (one healthy control, four patients with a neurodegenerative condition, and one coma patient). CMRGlu estimates in vivo were obtained with both the Sokoloff method and the Patlak method. Computer simulations were performed to assess the causes of bias affecting Sokoloff and Patlak estimates and interpret the results obtained in patients.Simulations showed that Sokoloff's method is less stable than Patlak's method as the extent of bias changed across different physiological states, potentially leading to misinterpretation of clinical data. In clinical patients, Sokoloff and Patlak estimates were correlated on the whole, but deviations emerged for critical physiological states.CMRGlu quantification with the Patlak method and aortic IDIF is feasible, easy to implement in clinical practice, and superior to Sokoloff's method from a personalized medicine perspective.

The neuropathological processes eventually leading to Alzheimer's disease (AD) are thought to start decades before the appearance of clinical symptoms and the clinical diagnosis of AD dementia. The term "preclinical AD" has been recently introduced to identify this "silent stage" of AD, when the disease is already present, but symptoms are not yet clinically evident. Advances in AD biomarkers have dramatically improved the ability to detect AD pathological processes in vivo in cognitively intact subjects, thus demonstrating the presence of AD pathology in the preclinical phase. This review focuses on the recent advances in the field of neuroimaging and CSF AD biomarkers specifically in the preclinical phase of AD, and aims to discuss the significance that such biomarkers could have in cognitively intact subjects. Even though the use of such biomarkers in AD preclinical phase has contributed to improve our understanding of AD early pathological processes, it raised also a number of new challenges that still remain to be overcome, such as a better definition of the clinical and individual significance of currently known biomarkers in preclinical stages and the development of novel biomarkers of different early AD-related events.

After advanced age, female sex is the major risk factor for Alzheimer's disease (AD). The biological mechanisms underlying the increased AD risk in women remain largely undetermined. Preclinical studies identified the perimenopause to menopause transition, a neuroendocrine transition state unique to the female, as a sex-specific risk factor for AD. In animals, estrogenic regulation of cerebral glucose metabolism (CMRglc) falters during perimenopause. This is evident in glucose hypometabolism and decline in mitochondrial efficiency which is sustained thereafter. This study bridges basic to clinical science to characterize brain bioenergetics in a cohort of forty-three, 40-60 year-old clinically and cognitively normal women at different endocrine transition stages including premenopause (controls, CNT, n = 15), perimenopause (PERI, n = 14) and postmenopause (MENO, n = 14). All participants received clinical, laboratory and neuropsychological examinations, 18F-fluoro-deoxyglucose (FDG)-Positron Emission Tomography (PET) FDG-PET scans to estimate CMRglc, and platelet mitochondrial cytochrome oxidase (COX) activity measures. Statistical parametric mapping and multiple regression models were used to examine clinical, CMRglc and COX data across groups. As expected, the MENO group was older than PERI and controls. Groups were otherwise comparable for clinical measures and distribution of APOE4 genotype. Both MENO and PERI groups exhibited reduced CMRglc in AD-vulnerable regions which was correlated with decline in mitochondrial COX activity compared to CNT (p's0.001). A gradient in biomarker abnormalities was most pronounced in MENO, intermediate in PERI, and lowest in CNT (p0.001). Biomarkers correlated with immediate and delayed memory scores (Pearson's 0.26≤r≤0.32, p≤0.05). These findings validate earlier preclinical findings and indicate emergence of bioenergetic deficits in perimenopausal and postmenopausal women, suggesting that the optimal window of opportunity for therapeutic intervention in women is early in the endocrine aging process.

Primary bone lymphoma (PBL) is a rare disease. Little is reported about response evaluation procedures in these patients. Our aim was to evaluate response to therapy according to fluorodeoxyglucose-positron emission tomography (FDG-PET) results, and in particular to test the Deauville 5-point scale as compared to the visual evaluation of FDG-PET scans in PBL. In this single-center study, we diagnosed 31 consecutive patients with PBL, of which 24 were evaluated with end-of-treatment FDG-PET. Patients' ages ranged from 19 to 82 years. Six patients were treated with chemotherapy, 24 with chemotherapy and radiotherapy, and one patient with radiotherapy alone. Six patients were affected by a pathological fracture. Four patients died within the range of 3 to 36 months after diagnosis. The average follow-up of the remaining patients was 70 (24–173) months. Overall survival was 87% at 5 years. The only positive prognostic factor was complete remission after chemotherapy. According to visual criteria, end-of-treatment FDG-PET was evaluated in 24 patients and it was positive in 11 (46%) and negative in 13 patients. We organized a retrospective central-blinded revision of end-of-therapy FDG-PET scans using the 5-point Deauville Score (DS). We reviewed 17 out of 24 patients and obtained the following results: at the end of therapy, 12 patients with DS score 2, three patients with DS score 3, one patient with DS score 4, and none with DS score 5. Considering that all the 24 patients achieved complete remission after treatment, visual interpretation produced 11/24 false-positive results, and DS interpretation produced 1/17 false-positive results, thus significantly reducing the number of false positives. In PBL, the final evaluation at the end of therapy with FDG-PET should be evaluated using Deauville 5-point scale in order to significantly reduce the risk of false-positive scans.

A new risk gene associated with amyotrophic lateral sclerosis (ALS) has recently been identified: the Tank-binding kinase 1 (TBK1) gene. Up to now, 90 TBK1 variants have been described in ALS patients with or without frontotemporal dementia (FTD), thus making TBK1 the third or fourth most frequent genetic cause of ALS and FTD. A point mutation analysis in a cohort of 69 Italian ALS patients was performed in order to analyze the frequency of TBK1 mutations and the correlation with clinical phenotypes. The analysis identified the novel variant p.Tyr424Asp in a patient with a rapid progression of the disease. Our data supports the implication of TBK1 in ALS pathogenesis in Italy.

Purpose Transmural abnormalities in myocardial blood flow (MBF) are important causes of ischaemia in patients with left ventricular (LV) hypertrophy. The study aimed to test whether pixel-wise parametric mapping of 13NH3 MBF can reveal transmural abnormalities in patients with hypertrophic cardiomyopathy (HCM).

In recent years, many efforts have been addressed to the development of new imaging techniques enabling early diagnosis and non-invasive monitoring of primary tumors and metastases. Among the integrin family, αVβ3 and α5β1 receptors have been characterized as prototypic markers of angiogenic tumor-associated endothelial cells and their overexpression in tumor cells has been correlated with the progression of various tumor types such as melanoma. Herein, we report the synthesis, characterization and preclinical evaluation of an 111In-labelled DOTA conjugate embodying a cyclic aminoproline-RGD-peptide motif as a competent αVβ3 integrin ligand, to be used as a radiotracer in preclinical models of human melanoma. Practical and efficient chemical and radiochemical synthetic procedures were set up, the in vitro stability and hydrophilicity of a cold c(AmpRGD)-DOTA conjugate were demonstrated, the binding affinities toward isolated αVβ3/α5β1 receptors were assayed and inhibition of cell adhesion to vitronectin and fibronectin was tested in human melanoma and endothelial progenitor cell lines. The anti-angiogenic activity of the peptide conjugates was also tested and assessed in vitro by tubulogenesis assays. The in vivo biodistribution SPECT/CT studies in healthy mice revealed high renal uptake at earlier observation times (30 min to 4 h p.i.) and complete clearance from the kidney at 48 h p.i.; the displacement experiments in human melanoma xenografts confirmed the αVβ3/α5β1 integrin specificity of tumor uptake, suggesting the 111In-labelled c(AmpRGD)-DOTA bioconjugate as a promising starting point in the search for new SPECT-imaging small-molecular probes for non-invasive visualization of tumor angiogenesis, human melanoma and other αVβ3/α5β1-positive tumors.

Epidemiological evidence linking diet, one of the most important modifiable lifestyle factors, and risk of Alzheimer's disease (AD) is rapidly increasing. However, there is little or no evidence for a direct association between dietary nutrients and brain biomarkers of AD. This study identifies nutrient patterns associated with major brain AD biomarkers in a cohort of clinically and cognitively normal (NL) individuals at risk for AD.Cross-sectional study.Manhattan (broader area).Fifty-two NL individuals (age 54+12 y, 70% women, Clinical Dementia Rating=0, MMSE27, neuropsychological test performance within norms by age and education) with complete dietary information and cross-sectional, 3D T1-weighted Magnetic Resonance Imaging (MRI; gray matter volumes, GMV, a marker of brain atrophy), 11C-Pittsburgh compound-B (PiB; a marker of fibrillar amyloid-β, Aβ) and 18F-fluorodeoxyglucose (FDG; a marker of glucose metabolism, METglc) Positron Emission Tomography (PET) scans were examined.Dietary intake of 35 nutrients associated with cognitive function and AD was assessed using the Harvard/Willet Food Frequency Questionnaire. Principal component analysis was used to generate nutrient patterns (NP) from the full nutrient panel. Statistical parametric mapping and voxel based morphometry were used to assess the associations of the identified NPs with AD biomarkers.None of the participants were diabetics, smokers, or met criteria for obesity. Five NPs were identified: NP1 was characterized by most B-vitamins and several minerals [VitB and Minerals]; NP2 by monounsaturated and polyunsaturated fats, including ω-3 and ω-6 PUFA, and vitamin E [VitE and PUFA]; NP3 by vitamin A, vitamin C, carotenoids and dietary fibers [Anti-oxidants and Fibers]; NP4 by vitamin B12, vitamin D and zinc [VitB12 and D]; NP5 by saturated, trans-saturated fats, cholesterol and sodium [Fats]. Voxel-based analysis showed that NP4 scores [VitB12 and D] were positively associated with METglc and GMV, and negatively associated with PiB retention in AD-vulnerable regions (p0.001). In addition, both METglc and GMV were positively associated with NP2 scores [VitE and PUFA], and negatively associated with NP5 scores [Fats] (p0.001), and METglc was positively associated with higher NP3 scores [Anti-oxidants and Fibers] (p0.001). Adjusting for age, gender, ethnicity, education, caloric intake, BMI, alcohol consumption, family history and Apolipoprotein E (APOE) status did not attenuate these relationships. The identified 'AD-protective' nutrient combination was associated with higher intake of fresh fruit and vegetables, whole grains, fish and low-fat dairies, and lower intake of sweets, fried potatoes, high-fat dairies, processed meat and butter.Specific dietary NPs are associated with brain biomarkers of AD in NL individuals, suggesting that dietary interventions may play a role in the prevention of AD by modulating AD-risk through its effects on Aβ and associated neuronal impairment.

According to the literature, the APP Ala713Thr mutation is associated with Alzheimer's disease and cerebral amyloid angiopathy. We describe a case of dementia clinically compatible with frontotemporal dementia in an APP Ala713Thr mutation carrier in which both [18F]Florbetapir PET uptake and Aβ1-42 cerebrospinal fluid levels were normal. Further evidences are required to establish if this association is only incidental.

Taking advantage of the structural similarity between aspartic proteases, small-molecule peptidomimetic inhibitors that already showed activity towards Secreted Aspartic Protease 2 as anti-Candida agents and HIV protease inhibitors were exploited as potential BACE1 inhibitors. A focused library of 6,8-dioxa-3-azabicyclo[3.2.1]-octane peptidomimetic scaffolds was synthesized and assayed towards BACE1 enzyme, resulting in the identification of a thiolactam-containing hit compound possessing IC50 in the low micromolar range, and confirming the bicyclic acetal portion as a potential transition state analogue in the interaction with catalytic aspartic acid residues.

After advanced age, female sex is the major risk factor for Alzheimer’s disease (AD). The biological mechanisms underlying the increased AD risk in women remain largely undetermined. Preclinical studies identified the perimenopause to menopause transition, a neuroendocrine transition state unique to the female, as a sex-specific risk factor for AD. In animals, estrogenic regulation of cerebral glucose metabolism (CMRglc) falters during perimenopause. This is evident in glucose hypometabolism and decline in mitochondrial efficiency which is sustained thereafter. This study bridges basic to clinical science to characterize brain bioenergetics in a cohort of forty-three, 40–60 year-old clinically and cognitively normal women at different endocrine transition stages including premenopause (controls, CNT, n = 15), perimenopause (PERI, n = 14) and postmenopause (MENO, n = 14). All participants received clinical, laboratory and neuropsychological examinations, 18F-fluoro-deoxyglucose (FDG)-Positron Emission Tomography (PET) FDG-PET scans to estimate CMRglc, and platelet mitochondrial cytochrome oxidase (COX) activity measures. Statistical parametric mapping and multiple regression models were used to examine clinical, CMRglc and COX data across groups. As expected, the MENO group was older than PERI and controls. Groups were otherwise comparable for clinical measures and distribution of APOE4 genotype. Both MENO and PERI groups exhibited reduced CMRglc in AD-vulnerable regions which was correlated with decline in mitochondrial COX activity compared to CNT (p’s

Brain 18F-fluorodeoxyglucose (18F-FDG) PET allows the in vivo study of cerebral glucose metabolism, reflecting neuronal and synaptic activity. 18F-FDG-PET has been extensively used to detect metabolic alterations in several neurologic diseases compared with normal aging. However, healthy subjects have variants of 18F-FDG distribution, especially as associated with aging. This article focuses on 18F-FDG-PET findings in so-called normal brain aging, and in particular on metabolic differences occurring with aging and as a function of people’s gender. The effect of different substances, medications, and therapy procedures are discussed, as well as common artifacts.

On the basis of a previously discovered anti-α

Experimental studies suggest that doxycycline attenuates post-infarction remodelling and exerts protective effects on myocardial ischaemia/reperfusion injury. However, the effects of the drug in the clinical setting are unknown. The aim of this study was to examine the effect of doxycycline on left ventricular (LV) remodelling in patients with acute ST-segment elevation myocardial infarction (STEMI) and LV dysfunction.Open-label, randomized, phase II trial. Immediately after primary percutaneous coronary intervention, patients with STEMI and LV ejection fraction40% were randomly assigned to doxycycline (100 mg b.i.d. for 7 days) in addition to standard therapy, or to standard care. The echo LV end-diastolic volumes index (LVEDVi) was determined at baseline and 6 months. (99m)Tc-Sestamibi-single-photon emission computed tomography infarct size and severity were assessed at 6 months. We calculated a sample size of 110 patients, assuming that doxycycline may reduce the increase in the LVEDVi from baseline to 6 months50% compared with the standard therapy (statistical power80% with a type I error = 0.05). The 6-month changes in %LVEDVi were significant smaller in the doxycycline group than in the control group [0.4% (IQR: -16.0 to 14.2%) vs.13.4% (IQR: -7.9 to 29.3%); P = 0.012], as well as infarct size [5.5% (IQR: 0 to 18.8%) vs. 10.4% (IQR: 0.3 to 29.9%) P = 0.052], and infarct severity [0.53 (IQR: 0.43-0.62) vs. 0.44 (IQR: 0.29-0.60), P = 0.014], respectively.In patients with acute STEMI and LV dysfunction, doxycycline reduces the adverse LV remodelling for comparable definite myocardial infarct size (NCT00469261).

BackgroundBody image distortion is a core symptom of eating disorders. Functional magnetic resonance imaging (fMRI) studies on body image processing, described different patterns of neural response, mainly involving the inferior and superior parietal lobules, and the dorsolateral prefrontal cortex (DLPFC), with conflicting results.MethodsThe neural response to the view of their own body pictures (normal size and distorted) was evaluated in 18 female anorexia nervosa (AN) restricting type patients, and in 19 healthy female subjects (HC) using fMRI. Clinical assessment was performed by means of the structured clinical interview for DSM-IV and self-reported questionnaires.ResultsIn response to the body image distortion, patients and controls showed an inverse pattern of activation, with the widest extent of activation in the oversize condition in AN, while in the undersize condition in HC. AN and HC showed a similar pattern of neural response to the view of their own body, with an increased activation in the extrastriate body area, superior and inferior parietal lobule and prefrontal areas, although the extent of activation in HC was more limited as compared with AN patients. Increased activity in AN patients, compared with HC, was observed in the DLPFC in response to the oversized body picture and a significant correlation was found in AN patients between DLPFC activation and eating disorder psychopathology.ConclusionsOur findings suggest the existence of a continuum from normalcy to pathology in neural response to body image, and confirm the clinical relevance of body image distortion in AN, reinforcing the key role of attentive, executive and self-evaluation networks in AN visual processing of own distorted body image.

Quantitative maps of the cerebral metabolic rate of glucose (CMRGlc) derived from 2-18F-fluoro-2-deoxy-d-glucose (18F-FDG) positron emission tomography (PET) images are useful in brain studies, but practical methods are needed to allow their use in clinical routine. This review looks at the kinetic model at the basis of absolute quantification of CMRGlc and at the main methods for measuring CMRGlc using 18F-FDG PET, also focusing on some critical steps in the procedure.

The purpose of this study was to evaluate the potential usefulness of [18F]-Choline PET/CT in the restaging of prostate cancer patients, who presented a rising PSA.We evaluated 170 prostate cancer patients, previously radically treated, that were referred for restaging with [18F]-Choline PET/CT.A total of 129 patients (median PSA 4.29 ng/ml at relapse) showed one or more areas of high uptake on PET/CT scan, while 41 patients with a median PSA of 1.07 ng/ml at relapse showed negative PET/CT scans. No false negative was found, while 31 patients were identified as false positive. Specificity of Choline PET/CT in our series was 56.9 %, while sensibility was 100 %. At the time of restaging, a PSA value superior or equal to 1 ng/ml was found to be a statistically significant predictive factor of PET positivity, either at the univariate (p0.0001) and at the multivariate analysis (p0.0001).Based on our findings, [18F]-Choline PET/CT is confirmed as a useful diagnostic tool to detect early recurrence, in patients with increasing PSA after primary treatment. However, in case of a mild increase in PSA, positive results must be validated with other techniques, as specificity and positive predictive value of [18F]-Choline PET/CT decrease with the lower values of PSA.

Ischemia in hypertrophic cardiomyopathy (HCM) is caused by coronary microvascular dysfunction (CMD), which is detected by measuring myocardial blood flow (MBF) with PET. Whether CMD may be associated with ischemic left ventricular (LV) dysfunction is unclear. We therefore assessed LV ejection fraction (EF) reserve in HCM patients undergoing dipyridamole (Dip) PET.Resting and stressEighteen patients had preserved (group A) and 16 abnormal LVEF reserve (group B; range -7 to -32). Group B patients had greater wall thickness than group A, but resting volumes, LVEF, resting and Dip MBF, and myocardial flow reserve were similar. Group B had slightly higher summed stress score and summed difference score in visual analysis than group A, and a significantly higher summed stress wall motion score. In group B, resting TPG was slightly lower (1.31 ± 0.29 vs. 1.37 ± 0.34, p0.05), and further decreased after Dip, whilst in group A it increased (B = 1.20 ± 0.39, p 0.0001 vs. rest and vs. A = 1.40 ± 0.43). The number of segments per patient with TPG1 was higher than in group A (p 0.001) and was a significant predictor of impaired LVEF reserve (OR 1.86, p 0.02), together with wall thickness (OR 1.3, p 0.02).Abnormal LVEF response is common in HCM patients following Dip, and is related to abnormal TPG, suggesting that subendocardial ischemia might occur under Dip and cause transient LV dysfunction. Although in vivo this effect may be hindered by the adrenergic drive associated with effort, these findings may have relevance in understanding exercise limitation and heart failure symptoms in HCM.

The goal of this study is to determine the technical accuracy of segmental perfusion parameters assessed with quantitative cardiac PET imaging in the evaluation of coronary artery disease (CAD) in patients with stable angina. A cohort of patients who participated in the EVINCI protocol underwent an evaluation of coronary anatomy by invasive coronary angiography (ICA) and/or coronary computed tomography angiography (CCTA) and PET myocardial perfusion imaging with H2 15O, 13NH3 or 82Rb. PET studies were analyzed by two independent observers blinded to clinical and instrumental data, and classified as positive or negative for significant CAD using only segmental perfusion measurements and cut-off values from literature. On a per-patient basis, the overall inter-observer agreement on PET results was 90 % (kappa = 0.79), indicating substantial agreement. On a per-vessel basis, the inter-observer agreement on PET results was 88 % (kappa = 0.74) in the RCA territory, 94 % (kappa = 0.84) in the LAD territory and 94 % (kappa = 0.85) in the LCX territory. Segmental PET measurements correctly identified 85 % of the patients, resulting in a global sensitivity of 86 %, a specificity of 84 %, a positive predictive value (PPV) of 69 % and a negative predictive value (NPV) of 93 %. In vessel-based analyses, quantitative perfusion parameters had a sensitivity, specificity, PPV and NPV of 92 %, 82 %, 42 % and 99 %, respectively, for the detection of significant coronary stenoses in all major coronary arteries. The assessment of absolute myocardial perfusion parameters measured at a segment level lead to reliable and accurate identification of patients with significant coronary stenosis at ICA and/or CCTA.

In this paper, using a hybrid small-animal Micro SPECT/CT imaging system, we report that a new (125)I-Cilengitide-like RGD-cyclopentapeptide, containing d-morpholine-3-carboxylic acid, interacts in vivo with α(v)β(3) integrin expressed by melanoma cells. Images clearly show that the (125)I-compound has the capacity to monitor the growth of a melanoma xenograft. Indeed, retention of the labeled ligand in the tumor mass has a good tumor/background ratio, and a significant reduction of its uptake was observed after injection of unlabeled ligand. These results suggest that the use of (125)I-labeled morpholine-based RGD-cyclopentapeptides targeting α(v)β(3) positive tumors may play a role in future therapeutic strategies.

Clinical use of positron emission tomography (PET) is now well established in neurodegenerative disorders, especially in the diagnosis of dementia. Measurement of cerebral glucose metabolism is of significant value, and it facilitates early diagnosis, appropriate differential diagnosis, and the evaluation of drug treatment in patients with dementia. In addition, tracers offer new perspectives for studying the neuropathology of underlying dementia, such as the accumulation of amyloid proteins, tau-proteins, or the presence of neuroinflammation. Finally, PET tracer studies of different neurotransmitter systems in dementia may not only increase the understanding of pathophysiologic mechanisms of the different disorders, but also improve diagnostic accuracy. In conclusion, PET imaging with different tracers offers reliable biomarkers in dementia, which can assist clinicians in the diagnosis of different dementing disorders, especially in the situation of overlapping phenotypes.

AimsTo provide a review of the available literature about the functional neuroimaging of anorexia nervosa, and to summarize the possible role of neurobiological factors in its pathogenesis.MethodsA systematic review of the literature was performed using PubMed and Medline electronic database (1950–September 2009). Eligible studies were restricted to those involving the main parameters of cerebral activity and functional neuroimaging techniques. Findings of the reviewed studies have been grouped on a diagnostic subtype basis, and their comparison has been interpreted in terms of concordance.ResultsWe found a high level of concordance among available studies with regard to the presence of frontal, parietal and cingulate functional disturbances in both anorexia nervosa restricting and binge/purging subtypes. Concordance among studies conducted regardless of the anorexia nervosa subtypes suggests an alteration in temporal and parietal functions and striatal metabolism.ConclusionsThe most consistent alterations in anorexia nervosa cerebral activity seem to involve the dorsolateral prefrontal cortex, the inferior parietal lobule, the anterior cingulate cortex and the caudate nucleus. They may affect different neural systems such as the frontal visual system, the attention network, the arousal and emotional processing systems, the reward processing network, and the network for the body schema.

Because of persistent stunning, post-treatment functional abnormalities could identify the initial risk area. The study aims to detect myocardial salvage using post-revascularization gated SPECT in acute myocardial infarction (AMI) treated by reperfusion therapy.In 36 AMI patients, we performed a first gated SPECT injecting (99m)Tc-sestamibi before primary percutaneous coronary intervention (PCI), and a second 5 days later. The salvage index defined by the two perfusion images was compared with the value obtained by subtracting in the second gated SPECT the extent of perfusion defect from the extent of wall thickening abnormalities.The wall thickening salvage index correlated with the reference perfusion salvage index (Spearman's ρ = .92, P .0001), with a 95% limit of agreement = ±.25. The agreement between the classifications in salvage index tertiles of the reference and of the wall thickening salvage index was good (kappa = .75). All patients with optimal PCI result and 18/24 of those with intermediate or poor outcome were correctly classified.Comparing function and perfusion in a single post-PCI (99m)Tc-sestamibi gated SPECT it is possible to estimate myocardial salvage. This could have useful implications in studies comparing different treatment strategies for AMI.

The development of prevention therapies for Alzheimer's disease (AD) would greatly benefit from biomarkers that are sensitive to subtle brain changes occurring in the preclinical stage of the disease. Early diagnostics is necessary to identify and treat at risk individuals before irreversible neuronal loss occurs. In vivo imaging has long been used to evaluate brain structural and functional abnormalities as predictors of future AD in non-demented persons. Prior to development of amyloid-beta (Abeta) tracers for positron emission tomography (PET), the most widely utilized PET tracer in AD was 2-[18F]fluoro-2-Deoxy-D-glucose (FDG) PET. For over 20 years, FDG-PET has been used to measure cerebral metabolic rates of glucose (CMRglc), a proxy for neuronal activity, in AD. Many studies have shown that CMRglc reductions occur early in AD, correlate with disease progression, and predict histopathological diagnosis. This paper reviews reports of clinical and preclinical CMRglc reductions observed in association with genetic and non-genetic risk factors for AD. We then briefly review brain Abeta PET imaging studies in AD and discuss the potential of combining symptoms-sensitive FDG-PET measures with pathology-specific Abeta-PET to improve the early detection of AD.

Perfusion gated single photon emission computed tomography (SPECT) can assess with good reproducibility left ventricular (LV) volumes and ejection fraction (EF). Whether this reproducibility is maintained in long-term follow-up is unknown.We compared LV end-diastolic (ED) and end-systolic (ES) volumes (V) as well as EF calculated using gated SPECT and QGS software in 103 coronary artery disease patients studied twice at1-year interval because of standard clinical indications. Patients were divided into two groups: (A) 67 patients without major clinical changes and with stable resting perfusion and (B) 36 with modified clinical status or resting perfusion.The relationship between gated SPECT 2 EF (=y) and gated SPECT 1 EF (=x) was for group A: y=0.91 x + 5.34, r=0.92, p0.0001, SEE=4 and for group B: y=0.67 x + 13.6, r=0.63, p0.0001, SEE=10. The 95% limit of agreement was 8 EF units for group A and 20.6 EF units for group B. For EDV, the 95% limit of agreement was 22 ml for group A and 52 ml for group B. For ESV, the 95% limit of agreement was 13 ml for group A and 44 ml for group B.In stable patients with an unmodified resting perfusion pattern the functional parameters derived from perfusion gated SPECT have good reproducibility even after a prolonged time interval. This supports the value of gated SPECT for serial evaluations of LV function.

Female sex and advanced age have adverse prognostic meaning in acute myocardial infarction. Whether gender and/or age influence the relationship between infarct size, infarct severity, and left ventricular ejection fraction (LVEF) is unclear. We examined 460 patients (359 men) with acute myocardial infarction submitted to successful primary percutaneous coronary intervention. Infarct size, infarct severity, and LVEF were evaluated with perfusion gated SPECT at one month of index infarction. There were no significant correlations between age and infarct size or infarct severity, and between age and LVEF. Moreover, elderly age (≥75 years) did not influence the relationship between LVEF and infarct size or infarct severity. Conversely, there was a significant gender-related difference in the relationship between LVEF and infarct size (F = 20.5, P

After advanced age, having a parent affected with Alzheimer's disease (AD) is the most significant risk factor for developing AD among cognitively normal (NL) individuals. Although rare genetic mutations have been identified among the early-onset forms of familial AD (EOFAD), the genetics of the more common forms of late-onset AD (LOAD) remain elusive. While some LOAD cases appear to be sporadic in nature, genetically mediated risk is evident from the familial aggregation of many LOAD cases. The patterns of transmission and biological mechanisms through which a family history of LOAD confers risk to the offspring are not known. Brain imaging studies using 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) have shown that NL individuals with a maternal history of LOAD, but not with a paternal family history, express a phenotype characterised by a pattern of progressive reductions of brain glucose metabolism, similar to that in AD patients. As maternally inherited AD may be associated with as many as 20 per cent of the total LOAD population, understanding the causes and mechanisms of expression of this form of AD is of great relevance. This paper reviews known genetic mutations implicated in EOFAD and their effects on brain chemistry, structure and function; epidemiology and clinical research findings in LOAD, including in vivo imaging findings showing selective patterns of hypometabolism in maternally inherited AD; possible genetic mechanisms involved in maternal transmission of AD, including chromosome X mutations, mitochondrial DNA and imprinting; and genetic mechanisms involved in other neurological disorders with known or suspected maternal inheritance. The review concludes with a discussion of the potential role of brain imaging for identifying endophenotypes in NL individuals at risk for AD, and for directing investigation of potential susceptibility genes for AD.

Persistent abnormalities are usually not detected in patients with Takotsubo cardiomyopathy (TTC). Since sympathetically mediated myocardial damage has been proposed as a causative mechanism of TTC, we explored whether mental stress could evoke abnormalities in these patients.One month after an acute event, 22 patients fulfilling all TTC diagnostic criteria and 11 controls underwent resting and mental stress gated single photon emission computed tomography (SPECT). Perfusion, wall motion, transient ischaemic dilation (TID) and left ventricular (LV) ejection fraction (EF) were evaluated.None of the controls showed stress-induced abnormalities. Mental stress evoked regional changes (perfusion defects and/or wall motion abnormality) in 16 TTC subjects and global abnormalities (LVEF fall5% and/or TID1.10) in 13; 3 had a completely negative response. TID, delta LVEF and delta wall motion score were significantly different in TTC vs control patients: 1.08 + or - 0.20 vs 0.95 + or - 0.11 (p0.05), -1.7 + or - 6% vs 4 + or - 5% (p0.02) and 2.5 (0, 4.25) vs 0 (0, 0) (p0.002), respectively.Mental stress may evoke regional and/or global abnormalities in most TTC patients. The abnormal response to mental stress supports the role of sympathetic stimulation in TTC. Mental stress could thus be helpful for TTC evaluation.

The aim of the present study was to evaluate the reciprocal relationships between motor impairment, dopaminergic dysfunction, and cerebral metabolism (rCMRglc) in de novo Parkinson's disease (PD) patients.Twenty-six de novo untreated PD patients were scanned with (123)I-FP-CIT SPECT and (18)F-FDG PET. The dopaminergic impairment was measured with putaminal (123)I-FP-CIT binding potential (BP), estimated with two different techniques: an iterative reconstruction algorithm (BP(OSEM)) and the least-squares (LS) method (BP(LS)). Statistical parametric mapping (SPM) multiple regression analyses were performed to determine the specific brain regions in which UPDRS III scores and putaminal BP values correlated with rCMRglc.The SPM results showed a negative correlation between UPDRS III and rCMRglc in premotor cortex, and a positive correlation between BP(OSEM) and rCMRglc in premotor and dorsolateral prefrontal cortex, not surviving at multiple comparison correction. Instead, there was a positive significant correlation between putaminal BP(LS) and rCMRglc in premotor, dorsolateral prefrontal, anterior prefrontal, and orbitofrontal cortex (p0.05, corrected for multiple comparison).Putaminal BP(LS) is an efficient parameter for exploring the correlations between PD severity and rCMRglc cortical changes. The correlation between dopaminergic degeneration and rCMRglc in several prefrontal regions likely represents the cortical functional correlate of the dysfunction in the motor basal ganglia-cortical circuit in PD. This finding suggests focusing on the metabolic course of these areas to follow PD progression and to analyze treatment effects.

The aim of this study was to investigate the predictive potential of pre-operative regional cerebral blood flow (rCBF) in the pre-supplementary motor area (pre-SMA) and clinical factors in Parkinson’s disease (PD) patients treated with subthalamic nucleus (STN) stimulation. Methods Ten patients underwent rCBF SPECT and motor Unified Parkinson’s Disease Rating Scale (UPDRS) preand post-operatively during stimulation at 5 and 42 months. Statistical parametric mapping (SPM) was used to extract rCBF values in the pre-SMA because it is related with motor improvement. Post-operative outcomes included motor response to stimulation and percent improvement in UPDRS. Pre-operative predictors were explored by correlation test, linear regression and multivariate analyses. Results Higher pre-operative rCBF in the pre-SMA and younger age were associated with favourable outcomes at 5 and 42 months. Pre-operative rCBF results were significantly associated with baseline clinical factors. Conclusion This study shows that PD patients with younger age have higher rCBF values in the pre-SMA and better outcome, thus giving the rationale to the hypothesis that STN stimulation could be considered early in the course of disease.

3-Aza-6,8-dioxabicyclo[3.2.1]octane-based amino acids as reverse turn inducers have been introduced into cyclic peptidomimetics containing the RGD or DGR retro-sequence, in order to achieve a stereochemical scanning of the binding capability of the resulting molecules towards alpha(v)beta(3) and alpha(v)beta(5) integrins, resulting in retro-inverso DGR peptides as micromolar ligands. A comparative analysis between the conformational preferences of 4 and of its isomer 3, having the opposite RGD sequence, was reported with respect to the binding activity, giving insight into the factors affecting the preferential binding of 4 to the alpha(v)beta(5) integrin.

Two c[RGDfX] cyclopeptides, having either L- or D-morpholine-3-COOH (Mor) as the X amino acid were developed as ligands for alpha(v)beta(3)/alpha(v)beta(5) integrins. Biological assays showed only d-Mor-containing cyclopentapeptide capable to bind alpha(v)beta(3) integrin with a low nanomolar affinity according to a two-site model, thus revealing a connection between the configuration of Mor and the preferred binding to alpha(v)beta(3) integrin. Conformational analysis showed different structural preferences for the two peptides induced by the two enantiomeric cyclic amino acids, suggesting a role of the stereochemistry of Mor on the overall peptide conformation and on the presentation of the pharmacophoric Arg and Asp side chains.

One of the main features of Alzheimer's disease (AD) is the severe reduction of the cerebral metabolic rate for glucose (CMRglc). In vivo imaging using positron emission tomography with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG-PET) demonstrates consistent and progressive CMRglc reductions in AD patients, the extent and topography of which correlate with symptom severity. Increasing evidence suggests that CMRglc reductions occur at the preclinical stages of AD. CMRglc reductions were observed on FDG-PET before the onset of disease in several groups of at-risk individuals, including patients with mild cognitive impairment (MCI), often a prodrome to AD; presymptomatic individuals carrying mutations responsible for early-onset familial AD; cognitively normal elderly individuals followed for several years until they declined to MCI and eventually to AD; normal, middle-aged individuals who expressed subjective memory complaints and were carriers of the apolipoprotein E epsilon-4 allele, a strong genetic risk factor for late-onset AD. However, the causes of the early metabolic dysfunction forerunning the onset of AD are not known. An increasing body of evidence indicates a deficient or altered energy metabolism that could change the overall oxidative microenvironment for neurons during the pathogenesis and progression of AD, leading to alterations in mitochondrial enzymes and in glucose metabolism in AD brain tissue. The present paper reviews findings that implicate hypometabolism and oxidative stress as crucial players in the initiation and progression of synaptic pathology in AD.