Prediction and longitudinal study of CSF biomarkers in mild cognitive impairment.

OBJECTIVES: To longitudinally evaluate five cerebrospinal fluid (CSF) biomarkers in the transition from mild cognitive impairment (MCI) to Alzheimer's disease (AD). METHODS: A baseline and 2-year follow-up clinical and CSF study of 86 subjects, including 22 MCI patients that declined to AD (MCI-AD), 43 MCI that did not deteriorate (MCI-MCI) and 21 controls (NL-NL). All subjects were studied for total and phosphorylated tau (T-tau, P-tau(231)), amyloid beta (Abeta) Abeta(42)/Abeta(40) ratio, isoprostane (IP) as well as P-tau(231)/Abeta(42/40) and T-tau/Abeta(42/40) ratios. RESULTS: At baseline and at follow-up MCI-AD showed higher levels P-tau(231), T-tau, IP, P-tau(231)/Abeta(42/40) and T-tau/Abeta(42/40) ratios and lower Abeta(42)/Abeta(40) than MCI-MCI or NL-NL. Baseline P-tau(231) best predicted MCI-AD (80%, p<0.001) followed in accuracy by P-tau(231)/Abeta(42/40) and T-tau/Abeta(42/40) ratios (both 75%, p's<0.001), T-tau (74%, p<0.001), Abeta(42)/Abeta(40) (69%, p<0.01), and IP (68%, p<0.01). Only IP showed longitudinal effects (p<0.05). CONCLUSIONS: P-tau(231) is the strongest predictor of the decline from MCI to AD. IP levels uniquely show longitudinal progression effects. These results suggest the use of CSF biomarkers in secondary prevention trials.

The effects of normal aging and ApoE genotype on the levels of CSF biomarkers for Alzheimer's disease.

While cerebrospinal fluid (CSF) biomarkers are of use in the prediction and diagnosis of Alzheimer's disease our understanding of the background effects of age and the ApoE genotype is limited. Seventy-eight community-based normal volunteers (mean age 60+/-10 years, range 36-86) were examined to determine the relationships between CSF measures of total tau (T-tau), hyperphosphorylated tau (P-tau 231), amyloid beta (Abeta42/Abeta40 ratio), and isoprostane (IP) with age and ApoE genotype. The results showed that age by epsilon4 genotype interactions were found for P-tau231 (beta=1.82; p<0.05) and IP (beta=1.6; p<0.05). T-tau CSF concentration increased with age. The increasing CSF concentrations of P-tau and IP in epsilon4 carriers suggest that early tauopathy and oxidative stress may be related to the increased risk for AD. The data also suggest that T-tau changes are more age dependent than Abeta changes. The evidence that P-tau231 and IP are the earliest markers for the neuronal damage related to AD awaits longitudinal study.

Inflammation and Alzheimer's disease: possible role of periodontal diseases.

The molecular and cellular mechanisms responsible for the etiology and pathogenesis of Alzheimer's disease (AD) have not been defined; however, inflammation within the brain is thought to play a pivotal role. Studies suggest that peripheral infection/inflammation might affect the inflammatory state of the central nervous system. Chronic periodontitis is a prevalent peripheral infection that is associated with gram-negative anaerobic bacteria and the elevation of serum inflammatory markers including C-reactive protein. Recently, chronic periodontitis has been associated with several systemic diseases including AD. In this article we review the pathogenesis of chronic periodontitis and the role of inflammation in AD. In addition, we propose several potential mechanisms through which chronic periodontitis can possibly contribute to the clinical onset and progression of AD. Because chronic periodontitis is a treatable infection, it might be a readily modifiable risk factor for AD.

The pre-mild cognitive impairment, subjective cognitive impairment stage of Alzheimer's disease.

BACKGROUND: Subjective cognitive impairment (SCI) has been a common, but poorly understood condition, frequently occurring in older persons. METHODS: The past and the emerging literature on SCI and synonymously named conditions is reviewed. RESULTS: Findings include: (1) There is support from at least one longitudinal study for a long-standing concept of SCI as a pre-mild cognitive impairment (MCI) condition lasting approximately 15years. (2) There are complex relationships between SCI and depression and anxiety. (3) Differences in SCI subjects from age-matched non-SCI persons are being published in terms of cognitive tests, hippocampal gray matter density, hippocampal volumes, cerebral metabolism, and urinary cortisol levels. Psychometric and dementia test score differences between SCI and MCI subjects have long been evident. (4) Predictive electrophysiologic features of subsequent decline in SCI subjects are being published. CONCLUSIONS: Studies of therapeutic agents in SCI treatment and resultant Alzheimer's disease prevention appear to be feasible. These trials are also necessary from a public health perspective.

Alzheimer's disease and peripheral infections: the possible contribution from periodontal infections, model and hypothesis.

Alzheimer's disease (AD) affects approximately 4.5 million people in the U.S. and this number will increase as the population ages and the life-span increases. Therefore, of paramount importance is identifying mechanisms and factors that affect the risk of developing AD. The etiology and pathogenic mechanisms for AD have not been defined, although inflammation within the brain is thought to play a role. Consistent with this hypothesis, studies suggest that peripheral infections contribute to the inflammatory state of the central nervous system. Periodontitis is a prevalent, persistent peripheral infection associated with gram negative, anaerobic bacteria that are capable of exhibiting localized and systemic infections in the host. This review offers a hypothetical link between periodontitis and AD and will present possible mechanistic links between periodontitis related inflammation and AD. It will review the pathogenesis of periodontitis and the mechanisms by which periodontal infections may affect the onset and progression of AD. Since periodontitis is a treatable condition, it may be a readily modifiable risk factor for AD.

Hypometabolism and altered cerebrospinal fluid markers in normal apolipoprotein E E4 carriers with subjective memory complaints.

BACKGROUND: We examined whether cerebral metabolic rates for glucose (CMRglc) on 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) and cerebrospinal fluid (CSF) markers of Alzheimer's disease (AD) are altered in cognitively normal apolipoprotein E (ApoE) E4 carriers with subjective memory complaints (SMC). METHODS: Twenty-eight middle-aged normal subjects (NL) were examined, including 13 E4 carriers (E4+; 6 with SMC [SMC+] and 7 without SMC [SMC-]) and 15 noncarriers (E4-; 7 SMC+ and 8 SMC-). Subjects received an FDG-PET scan and a lumbar puncture to measure CSF total (T-Tau) and hyperphosphorylated tau(231) (P-Tau), 40 and 42 amino acid forms of beta-amyloid (Abeta40 and Abeta42), and F(2)-isoprostane (IP). RESULTS: As compared with E4-, E4+ subjects showed decreased CMRglc in AD-related brain regions and associated higher CSF IP, P-Tau, T-Tau, and P-Tau/Abeta42 levels (p's < .05). As compared with SMC-, SMC+ subjects showed reduced parietotemporal and parahippocampal gyrus (PHG) CMRglc. A significant ApoE by SMC status interaction was found, with the E4+/SMC+ showing the lowest PHG CMRglc and the highest CSF IP, P-Tau, and P-Tau/Abeta42 levels as compared with all other subgroups (p's < or = .05). The combination of CSF and CMRglc measures significantly improved the accuracy of either measures alone in discriminating ApoE groups (86% accuracy, odds ratio [OR] = 4.1, p < .001) and E4+/SMC+ from all other subgroups (86% accuracy, OR = 3.7, p = .005). Parahippocampal gyrus CMRglc was the most accurate discriminator of SMC groups (75% accuracy, OR = 2.4, p < .001). CONCLUSIONS: Normal E4 carriers with SMC show altered AD-related CSF and FDG-PET measures. Longitudinal studies are needed to assess whether these brain abnormalities foreshadow clinical decline.

Subjective memory complaints: presence, severity and future outcome in normal older subjects.

BACKGROUND/AIMS: Subjective memory complaint (SMC) in normal individuals may predict future cognitive decline. The goal of this study was to examine whether the probability of decline increases with growing intensity of complaint. METHODS: Normal subjects over the age of 50 years were included in a longitudinal retrospective study (mean follow-up time = 8 years). All subjects (n = 230) underwent cognitive and medical examination at baseline. The presence of SMC was determined based on Global Deterioration Scale staging. A subgroup of 83 participants also received baseline assessment for the intensity of SMC. Logistic regression was used to predict outcome from baseline variables. Three outcome groups were established at the final visit: nondeclining, declining and diagnostically unstable (i.e. the diagnosis changed over time: from normal to mild cognitive impairment, then back to normal). RESULTS: The presence of SMC was a predictor of future decline but also increased the likelihood of the unstable diagnosis. Increasing intensity of SMC did not further raise the risk for decline. High intensity of complaints and more pronounced affective symptoms predicted the unstable clinical diagnosis. CONCLUSIONS: The presence of SMC contributes to the risk of future decline, however, the increasing intensity of the perceived impairment does not further enhance the risk.

Early detection of Alzheimer's disease using neuroimaging.

Neuroimaging is being increasingly used to complement clinical assessments in the early detection of Alzheimer's disease (AD). Structural magnetic resonance imaging (MRI) and metabolic positron emission tomography (FDG-PET) are the most clinically used and promising modalities to detect brain abnormalities in individuals who might be at risk for AD but who have not yet developed symptoms. The knowledge of established risk factors for AD enabled investigators to develop enrichment strategies for longitudinal imaging studies to reduce the sample sizes and study duration. The present review focuses on the results obtained by MRI and FDG-PET studies that examined the preclinical AD stages in several at risk populations: (1) individuals from families with autosomal dominant early-onset AD (FAD), (2) patients with mild cognitive impairment (MCI), particularly in memory, who are at very high risk for declining to AD with an estimated decline rate of 10-30% per year, (3) normal young and middle-age subjects carriers of known susceptibility genes for late-onset AD such as the Apolipoprotein E (ApoE) E4 allele, and (4) as age is the main risk factor for AD, normal elderly individuals followed to the onset of MCI and AD. Overall, these studies show that the use of imaging for the early detection of AD is successful even in the earlier stages of disease when clinical symptoms are not fully expressed and the regional brain damage may be limited.

Single voxel proton magnetic resonance spectroscopy in post-stroke depression.

Mood disorders are associated with structural, metabolic and spectroscopic changes in prefrontal regions. In the case of depression associated with stroke, there is little information about the biochemical profile of these regions, as assessed by proton magnetic resonance spectroscopy ((1)H-MRS). In a group of first-ever stroke patients, we studied the association between post-stroke depression and (1)H-MRS measurements in unaffected frontal lobes. Twenty-six patients with a first ischemic stroke located outside the frontal lobes were included in the study. Single voxel proton magnetic resonance spectroscopy ((1)H-MRS) was performed to assess N-acetylaspartate/creatine (NAA)/Cr, glutamate+glutamine (Glx)/Cr, choline (Cho)/Cr and myo-inositol (mI)/Cr ratios. Patients were assessed within the first 10 days after stroke and again four months later. The diagnosis of depression was made on the basis of clinical observation, interview and Hamilton Depression Rating Scale scores. In a group of 26 patients, eight (31%) met criteria for depression at the first assessment, and nine (35%) met criteria for depression at follow-up. Patients with depression in the immediate post-stroke phase had significantly higher Glx/Cr ratios in the contralesional hemisphere than non-depressive patients. No biochemical differences were found between the groups at 4-month follow-up. These findings suggest that post-stroke depression is accompanied by changes in frontal lobe glutamate/glutamine levels, perhaps reflecting abnormalities in glutamatergic transmission in the immediate post-stroke period.

[Vascular abnormalities in patients with primary intracerebral hemorrhage]. / Malformacje naczyn mózgowych u chorych z pierwotnym krwotokiem sródmózgowym.

BACKGROUND: To prevent the recurrence of primary intracerebral hemorrhage (PIH) it is important to identify patients with underlying structural vascular abnormalities (VA). According to previous study data-- the site of hemorrhage, the patient's age and pre-existing hypertension affect the likelihood of finding VA. However, the indications for angiography, the gold standard for the diagnosis of VA, still remain controversial. PURPOSE: To assess the frequency of VA and to determine features that might increase the probability of finding VA in patients with PIH. MATERIAL AND METHODS: 100 patients with PIH, without a history of trauma, coagulopathy, or known pre-existing brain abnormality, who were admitted to the Stroke Unit of the Department of Neurology, Jagiellonian University, between January 1999 and November 2000 entered this prospectively designed study. In the group of 96 patients, 53 persons underwent conventional angiography within 14 days of stroke onset (in 4 cases we found bleeding into the tumor and these patients were not included in further analysis). RESULTS: Vascular abnormalities were found in 14 of 53 patients (26.4%); ruptured aneurysms in 9 patients (17.0%), arteriovenous malformations (AVM) in 3 patients (5.7%), venous angioma in 1 patient (1.8%) and cavernous angioma in 1 patient (1.9%). Vascular malformations were found in 12 of 25 patients with lobar hemorrhage, in 1 of 8 patients with hemorrhage originating in the thalamus and in 1 of 2 patients with hemorrhage originating in the pons. Angiographic findings were negative in 8 patients with hemorrhage in the periventricular white matter, in 8 with hemorrhage originating in the basal ganglia and in 2 patients with hemorrhage in the cerebellum. Patients with VA were significantly younger than patients without VA (49.9 +/- 11.7 years and 58.7 +/- 13.3 years respectively, p = 0.03) and they had a history of hypertension significantly less often (50.0% and 89.7%, p = 0.001). Intraventricular hemorrhage and subarachnoid bleeding occurred in a similar percentage of patients with ICH, independent of whether or not they had VA (28.6% and 38.5%; 21.4% and 10.3% respectively, p = n.s.). CONCLUSIONS: (1) A vascular abnormality is the cause of about 26% of ICH, with a higher likelihood in younger patients and with lobar hemorrhage. (2) A history of hypertension does not exclude the presence of VA. (3) Intraventricular hemorrhage or subarachnoid bleeding does not predict the presence of VA.

Reduced prefrontal N-acetylaspartate in stroke patients with apathy.

BACKGROUND: Although substantial numbers of stroke patients suffer from apathy, its causes are still poorly understood. Previous studies suggest that dysfunction of the frontal lobes is implicated in the pathophysiology of motivation. Our aim was to investigate the association between proton magnetic resonance spectroscopy (H1-MRS) measurements in unaffected frontal lobes and apathy in a group of first-time stroke patients. METHODS: 31 patients with a first-time ischemic stroke located outside the frontal lobes and 20 healthy subjects were included in the study. The authors performed single voxel H1-MRS in order to measure the N-acetylaspartate/creatine (NAA)/Cr, glutamate+glutamine (Glx)/Cr, choline (Cho)/Cr and myo-inositol (mI)/Cr ratios in the frontal lobes. Patients were assessed between days 7 and 12 post stroke. Diagnosis of apathy was made on the basis of clinical observation, interview and Apathy Scale. RESULTS: 13 out of 31 patients (42%) demonstrated apathy. Patients with apathy had lower NAA/Cr ratios in the right frontal lobe than non-apathetic subjects. The patient group was divided into two subgroups: Those with left hemisphere strokes, and those with right hemisphere strokes. Of these subjects, significantly lowered NAA/Cr ratios were found in the right hemispheres of apathetic patients in the subgroup with left-sided brain lesions. CONCLUSIONS: These findings point to the association between apathy and frontal lobe integrity, suggest different reactions of the hemispheres and indicate that changes in the NAA/Cr ratio are related to the apathy.

The role of quantitative structural imaging in the early diagnosis of Alzheimer's disease.

The goal of this article is to review the role of structural neuroimaging in the diagnosis of Alzheimer's disease (AD). We present relevant neuroanatomy, highlight progress in the domain of AD imaging, and review the clinical characteristics of the prodromal phase of AD. We describe the history of the diagnostic issue by examining at cross-section and longitudinally the differences between patients who have AD and normal controls. We also present how subsequent works applied these characteristic traits to the early detection of the prodromal disease and to prediction of future decline. The article delineates the differences between subjects who have mild cognitive impairment and AD, which illustrate the spreading of the pathology with disease progression. The last section describes problems encountered in the differential diagnosis.

A2 alelle of GpIIIa gene is a risk factor for stroke caused by large-vessel disease in males.

BACKGROUND AND PURPOSE: Glycoprotein IIIa (GpIIIa) is a platelet membrane receptor for fibrinogen and von Willebrand factor. It plays a key role in platelet aggregation. Previous studies in stroke patients, without analysis based on specific subtypes of stroke cause, have not shown any link between GpIIIa A1/A2 polymorphism and stroke risk. We studied the significance of the GpIIIa gene A1/A2 polymorphism in stroke patients with different stroke causes. METHODS: We genotyped 92 patients with stroke caused by large-vessel disease (LVD stroke) and 184 matched controls; 103 patients with stroke caused by small-vessel disease (SVD stroke) and 206 controls; and 182 patients with cardioembolic stroke (CE stroke) and 182 controls (TOAST criteria). The GpIIIa A1/A2 polymorphism was analyzed by polymerase chain reaction followed by restriction enzyme digestion and electrophoresis. RESULTS: The genotype distribution of the GpIIIa gene in patients with LVD stroke (A1/A1, 63%; A1/A2, 34.8%; A2/A2, 2.2%) differed significantly from their controls (A1A1, 79.3%; A1/A2, 20.1%; A2/A2, 0.6%). The distribution of the GpIIIa A1/A2 polymorphism in patients with SVD stroke and CE stroke was similar to that of their controls. In contrast to females with LVD stroke, we found that males with LVD stroke presented with an overrepresentation of at least 1 A2 allele of the GpIIIa gene when compared with their controls (39.7% versus 23.0%; P=0.003). Conditional logistic regression analysis showed that possession of at least 1 A2 allele of the GpIIIa gene was an independent risk factor for LVD stroke in males (OR, 2.51; 95% CI, 1.21 to 5.20). CONCLUSIONS: A2 allele of the GpIIIa gene is an independent risk factor for LVD stroke in males.

GABA in ischemic stroke. Proton magnetic resonance study.

BACKGROUND: Experimental studies have suggested that ischemic stroke causes increment in extracellular level of gamma-aminobutyric acid in response to excessive glutamate concentration and function. The increased GABA concentration is followed by subsequent inhibition of GABA synthesis, thus leading to GABA-ergic dysfunction Enhancing GABA function seems to be a way of neuroprotec- tion after cerebral insult. Animal models have shown there is overactivity of excitatory neurotransmitters and decreased tone of GABA-ergic system also in the remote neocortical regions. Data concerning changes in brain areas outside the stroke lesion in humans are sparse. These region could be possible targets for therapeutic intervention. Progress in imaging techniques enables separation of a great number of chemical compounds .Our aim was to assess GABA levels outside the ischemic lesion by means of proton magnetic resonance spectroscopy ((1) H MRS). MATERIAL AND METHODS: The study compared 31 patients with first-ever ischemic stroke and 20 healthy subjects. Single voxel H(1) MRS was performed to measure GABA/Cr ratios in structurally normal prefrontal regions, distant from the stroke lesion. The amount of the remaining metabolites (NAA, Cho, mI, Glx) was also estimated. Patients underwent the examination in the acute phase of the disease and 3 months later. RESULTS: Both early after stroke and more than 3 months later, the patients had lower GABA levels. However, during the second examination, this difference was evident only in the frontal cortex ipsilateral to the lesion. CONCLUSIONS: These findings suggest that GABA function is decreased outside the infarct. Further studies are needed for confirmation of the results and elucidation of the possible role of GABA alterations in stroke recovery and therapy.

[Depressive symptoms following ischemic stroke]. / Objawy depresyjne po udarze niedokrwiennym mózgu.

Depressed mood and other depressive symptoms frequently seen after cerebral stroke contribute to an unfavorable prognosis in this patient population. Identification of the subgroup of patients at increased risk for depressive symptoms is a prerequisite of early treatment. In the study aimed at evaluation of post-stroke depressive symptoms prevalence and risk factors participants were 766 consecutive patients with ischemic cerebral infarction, admitted in the years 1997-2000 to the Stroke Unit, Neurology Department in Cracow. Data concerning depressive symptoms, demographic characteristics and clinical variables were obtained from medical records. Depressive symptoms during the hospitalization were found in 19% of cases. Younger age, neurological deficits and previous history of psychiatric disorders were independent factors increasing the risk of post-stroke depressive symptoms. The study allowed to identify the subpopulation of stroke patients at risk for affective disorders following a cerebrovascular accident.