Does use of antihypertensive drugs affect the incidence or progression of dementia? A systematic review
ABSTRACT Hypertension appears to contribute to the development of dementia. Antihypertensive drugs may play an important role in altering the incidence or progression of dementia, particularly dementia of the vascular type; however, the neuroprotective effects of these agents in other types of dementia are not well characterized.
The main aims of this review were to examine the relationship between use of antihypertensive agents and the incidence and progression of Alzheimer's dementia (AD), vascular dementia (VaD), and unspecified dementia, and to consider whether these agents may be neuroprotective.
A search of the English-language literature (January 1996-August 2009) was conducted using PubMed, Ovid MEDLINE, EBSCO MEDLINE, and the Cochrane Database of Systematic Reviews for publications mentioning both antihypertensive drugs and dementia. A combination of searches was performed using the following terms: antihypertensive drugs, dementia, cognitive impairment, Alzheimer's dementia, vascular dementia, progression of cognitive impairment, severity of cognitive impairment, severity of dementia, prevalence, and incidence. Searches were also performed using the names of antihypertensive drug classes. The bibliographies of all retrieved articles were reviewed for additional relevant publications. The focus was on randomized controlled trials, cohort studies, and case-control studies, excluding studies in animals, patients aged <45 years, drugs other than antihypertensive agents, and the role in cognition of hormones, receptors, and enzymes.
Sixty-five potentially relevant articles were identified from the 536 publications retrieved by the literature search. After application of the exclusion criteria, 12 original studies were included in the review, all published between 1999 and 2008 and most involving patients with AD or VaD. The most frequently studied antihypertensive agents were calcium channel blockers (7 studies), diuretics (6 studies), and angiotensin-converting enzyme (ACE) inhibitors (6 studies). Overall, these medications appeared to be beneficial in dementia, but only ACE inhibitors and diuretics significantly reduced the risk for and progression of dementia in the majority of studies.
Antihypertensive medications-particularly ACE inhibitors and diuretics-may be helpful in reducing the risk for and progression of dementia. Large randomized clinical trials are warranted to further explore the relationship between antihypertensive drugs and dementia.
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ABSTRACT: Angiotensin II (Ang II) is the main active product of the renin-angiotensin system (RAS), mediating its action via two major receptors, namely, the Ang II type 1 (AT(1)) receptor and the type 2 (AT(2)) receptor. Recent results also implicate several other members of the renin-angiotensin system in various aspects of brain functions. The first aim of this paper is to summarize the current state of knowledge regarding the properties and signaling of the AT(2) receptor, its expression in the brain, and its well-established effects. Secondly, we will highlight the potential role of the AT(2) receptor in cognitive function, neurological disorders and in the regulation of appetite and the possible link with development of metabolic disorders. The potential utility of novel nonpeptide selective AT(2) receptor ligands in clarifying potential roles of this receptor in physiology will also be discussed. If confirmed, these new pharmacological tools should help to improve impaired cognitive performance, not only through its action on brain microcirculation and inflammation, but also through more specific effects on neurons. However, the overall physiological relevance of the AT(2) receptor in the brain must also consider the Ang IV/AT(4) receptor.12/2012; 2012:351758. DOI:10.1155/2012/351758
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ABSTRACT: Verbal comprehension is critical to the success of medical counseling. Here, we tested how age and vascular risk factors affect the ability to understand complex instructions. Verbal comprehension, cognitive functions, and vascular risk factors were assessed in 39 mid- and 38 late-life community-dwelling individuals (48 to 59 years and >59 years of age, respectively). To test for verbal comprehension, we used a modified version of the Token Test (TT). In midlife individuals, education (β = 0.572, p < 0.05) was the only predictor for extended-TT performance. In late-life individuals, age (β = -1.015, p < 0.001) and body mass index (β = -0.651, p = 0.003) were significantly correlated with extended-TT performance and explained 50% of the variance in extended-TT performance (adjusted R (2) = 0.503). This relation is only partly explained by conventional neuropsychological measures as the ones used in our test battery. These results indicate that aging and overweight impair comprehension of complex instructions. Therefore, medical counseling appropriate for midlife individuals may be less successful in elderly people and particularly in those with metabolic disturbances.Age 03/2011; 33(1):101-6. DOI:10.1007/s11357-010-9161-9 · 3.45 Impact Factor
Conference Paper: Instrumentation system to improve ISFET behaviour[Show abstract] [Hide abstract]
ABSTRACT: Solid state chemical sensors have many advantages over conventional glass electrodes, such as smaller size, faster response and lower cost. Nevertheless, the limitations imposed by their temporary drifts, thermal dependencies and hysteresis must be considered in these sensors' performance. These limitations are not so important in applications that do not require high precision. But in the case of biomedical applications they cannot be ignored. We introduce a new electronic conditioning circuit plus a virtual instrumentation that cancels or reduces these limitations. As result of the study, we can conclude that the new measurement method allows a 0.06 pH precision. The conditioning circuit maintains stable sensor feedback in an automatic way, independent of its temporary drifts and thermal dependencies.Instrumentation and Measurement Technology Conference, 2002. IMTC/2002. Proceedings of the 19th IEEE; 02/2002