Angiotensin converting enzyme deletion allele in different kinds of dementia disorders.

In order to verify the association of Angiotensin converting enzyme (ACE) gene with different kinds of dementia, as well as its association with APO-E (genotype), we performed ACE genotyping in subjects with late-onset probable Alzheimer's disease (LOAD, n = 64), early-onset probable Alzheimer's disease (EOAD, n = 32), possible Alzheimer's disease (pAD, n = 44), vascular dementia (VD, n = 12), age-associated memory impairment (AAMI, n = 15) and 40 healthy age-matched controls, who were previously characterized for APO-E. After the principal component analysis ACE D and Apo-Eepsilon4 alleles disclosed the highest prevalence in the cognitively impaired groups of subjects, Apo-Eepsilon4 being more specific for LOAD and pAD. ACE D allele seems to be an unspecific susceptibility factor for mental decline.

Increased cerebrospinal fluid pyruvate levels in Alzheimer's disease.

Impaired energy metabolism is an early, predominant feature in Alzheimer's disease. In order to find out simple, reliable 'in vivo' markers for the clinical-biological typization of the disorder, we measured cerebrospinal fluid (CSF) glucose, lactate and pyruvate levels in patients suffering from dementia of Alzheimer type (DAT) and in healthy elderly controls. DAT group showed remarkably higher levels of pyruvate (P = 0.01), with no overlap with the values obtained in controls. CSF pyruvate levels were also significantly associated with the severity of dementia. Therefore, CSF pyruvate levels neatly separate DAT patients from controls, having also pathogenetic value.

Serum autoantibodies against glial fibrillary acidic protein in brain aging and senile dementias.

Autoantibodies against glial fibrillary acidic protein (GFAP) were investigated by ELISA test in sera of patients suffering from senile dementias and in healthy aging people. One hundred eight subjects divided into control, vascular dementia (VD), presenile Alzheimer's disease (AD), and senile Alzheimer's disease (SDAT) groups were included in the study. VD patients showed the highest antibody titers when compared to controls, whereas AD had the lowest titers when compared to the other groups. These results do not support the utility of anti-GFAP antibodies as useful markers of Alzheimer's disease, suggesting that their presence is a secondary phenomenon to blood-brain barrier disruption.

Platelet MAO-B activity and vitamin B12 in old age dementias.

Platelet MAO-B activity, serum vitamin B12 levels, and plasma folate were measured in patients suffering from presenile (AD) and senile (SDAT) dementia of Alzheimer-type, and vascular dementia (VD). MAO-B was higher in the SDAT group than in AD and controls. An inverse relationship between MAO-B activity and vit. B12 levels was documented in the whole group and in each category studied; furthermore, MAO-B was positively related to age. All the patients were then divided into two groups, according to vit. B12 levels (Group I: less than 200 pg/mL; Group II: greater than or equal to 200 pg/mL); Group I showed a significantly higher MAO-B activity with respect to Group II. The results indicate the existence of a negative association between platelet MAO-B activity and serum levels of vitamin B12 and confirm the existence of biological differences between presenile and senile dementia of Alzheimer type.

CSF monoamine metabolites in old age dementias.

Cerebrospinal Fluid (CSF) levels of the main metabolites of monoamines (MHPG, 5-HIAA, and HVA) were measured in patients with early onset (AD) and late-onset (SDAT) Alzheimer's disease, vascular dementia (VD), and elderly controls. Psychobehavioral assessment was carried out by means of MMSE and GBS. Mean MHPG levels did not differ from controls; 5-HIAA was lower in VD when compared to both controls and SDAT. HVA was decreased in AD, SDAT, and VD with respect to controls. Significant correlations between HVA and psycho-behavioral parameters were observed in SDAT and VD groups, whereas no relationship was documented in AD. The SDAT group was divided in SDAT-A (age at onset: greater than 65 less than or equal to 80 yr) and SDAT-B (age at onset: greater than 80 yr). SDAT-A had significantly lower CSF HVA values than SDAT-B (165 +/- 64 vs 235.7 +/- 85). SDAT-B HVA levels were similar to those observed in controls. Correlation analysis between HVA and neuropsychological variables was significant in SDAT-A, but not in SDAT-B. These results might support the evidence of SDAT heterogeneity.

Pharmacokinetics of IV and oral acetyl-L-carnitine in a multiple dose regimen in patients with senile dementia of Alzheimer type.

Acetyl-L-carnitine (ALC), a physiological component of the L-carnitine family, has been proposed for treating Alzheimer's disease in pharmacological doses. As this condition requires prolonged therapy, its kinetics has been examined after a multiple dose regimen, involving different routes of administration, in 11 patients suffering from Senile Dementia of Alzheimer Type. The study design comprised a 3-day basal observation period, sham treatment with repeated blood sampling; treatment with 30 mg.kg-1 i.v. [corrected] for 10 days (plasma kinetics was studied on the 7th day), and 50 days of 1.5 g/day [corrected] p.o. given in three daily doses. Total acid soluble L-carnitine, L-carnitine and acetyl-L-carnitine in plasma and CSF were evaluated using an enantioselective radioenzyme assay. Short chain L-carnitine esters were calculated as the difference between total and free-L-carnitine. The plasma concentrations of individual components of the L-carnitine family did not change during the three days of the basal period, nor were they affected during the sham therapy period. Following the i.v. bolus injections, the plasma concentrations showed a biphasic curve, with average t1/2 of 0.073 h and 1.73 h, respectively. At the end of oral treatment, plasma acetyl-L-carnitine and L-carnitine short chain esters were significantly higher than during the run-in phase. The CSF concentrations paralleled those in plasma, suggesting that ALC easily crosses the blood-brain barrier. It is concluded that i.v. and oral administration of multiple doses of ALC can increase its plasma and CSF concentration in patients suffering from Alzheimer's disease.

Blood-brain-barrier in a geriatric population: barrier function in degenerative and vascular dementias.

Albumin and IgG were determined in serum and cerebrospinal fluid (CSF) of patients with early-onset Alzheimer's disease (AD, n. 13), senile dementia of Alzheimer type (SDAT, n. 33), vascular dementia divided into multi-infarct (MID, n. 9) and probable vascular (PVD, n. 11) dementia. Albumin and IgG ratio and IgG index were calculated. CSF albumin and albumin ratio were significantly higher in MID patients indicating an increased BBB permeability. IgG ratio and IgG index did not show any significant difference among groups. These results do not provide evidence for BBB damage in AD/SDAT, while in MID the increase of CSF albumin and albumin ratio is suggestive of BBB dysfunction.

Is multi-infarct dementia representative of vascular dementias? A retrospective study.

Multi-infarct dementia (MID) indicates a dementia disorder primarily caused by multiple cerebral infarcts. Since other pathogenetic mechanisms cause vascular dementia we evaluated clinical, CT scan and CSF neurochemical parameters of 134 MID and 67 PVD (probable vascular dementia) patients. We found no differences with regard to the presence of major risk factors. Only TIA/stroke episodes and focal neurological signs were significantly more frequent in MID than in PVD cases, an anticipable result on the basis of MID definition. CT scan findings showed a prevalence of subcortical with respect to cortical lesions in both groups, with a higher frequency in MID patients. Subjects with deep infarcts more frequently showed TIA/stroke episodes and diabetes mellitus. No differences were detectable in CSF monoamine metabolite levels. We conclude that in the majority of vascular dementias subcortical damage seems to have a major pathogenetic role.

Comparative kinetics of oxiracetam in serum and CSF of patients with dementia of Alzheimer type.

The purpose of the study was to determine whether oxiracetam crosses the human blood-brain barrier and to evaluate its comparative kinetics in serum and in cerebro-spinal fluid (CSF). Six DAT patients, undergoing CSF collection for diagnostic purposes, received 2 g oxiracetam daily, by a 60 min i.v. infusion, for 7 days. On the last day, in four patients blood samples were collected at time 0, 30, 60 and 120 min, and lumbar drainage was performed at the end of infusion: at this time mean CSF concentration was 3.5 micrograms/ml, i.e. 4.0% of the serum one, demonstrating that oxiracetam crosses the blood-brain barrier. In two patients, blood samples were collected at time 0, 60, 120 and 240 min, and lumbar drainage was performed 60 min after the end of infusion: at this time mean CSF concentration was 2.8 micrograms/ml, i.e. 5.3% of the serum one, indicating a persistence of oxiracetam within this deep compartment. These results provide the first evidence in humans that oxiracetam penetrates the central nervous system and contribute to the understanding of its long-lasting pharmacodynamic effect in man.