Antihypertensives for combating dementia? A perspective on candidate molecular mechanisms and population-based prevention

Age-related increases in prevalent dementia over the next 30–40 years risk collapsing medical resources or radically altering the way we treat patients. Better prevention of dementia therefore needs to be one of our highest medical priorities. We propose a perspective on the pathological basis of dementia based on a cerebrovascular-Alzheimer disease spectrum that provides a more powerful explanatory framework when considering the impact of possible public health interventions. With this in mind, a synthesis of evidence from basic, clinical and epidemiological studies indeed suggests that the enhanced treatment of hypertension could be effective for the primary prevention of dementia of either Alzheimer or vascular etiology. In particular, we focus on candidate preventative mechanisms, including reduced cerebrovascular disease, disruption of hypoxia-dependent amyloidogenesis and the potential neuroprotective properties of calcium channel blockers. Following the successful translation of large, long-term and resource-intense trials in cardiology into improved vascular health outcomes in many countries, new multinational prevention trials with dementia-related primary outcomes are now urgently required

α 1

Rationale: α(1)-Antitrypsin (A1AT) was identified as a plasma protease inhibitor; however, it is now recognized as a multifunctional protein that modulates immunity, inflammation, proteostasis, apoptosis, and cellular senescence. Like A1AT, protein phosphatase 2A (PP2A), a major serine-threonine phosphatase, regulates similar biologic processes and plays a key role in chronic obstructive pulmonary disease. Objectives: Given their common effects, this study investigated whether A1AT acts via PP2A to alter tumor necrosis factor (TNF) signaling, inflammation, and proteolytic responses in this disease. Methods: PP2A activity was measured in peripheral blood neutrophils from A1AT-deficient (PiZZ) and healthy (PiMM) individuals and in alveolar macrophages from normal (60 mg/kg) and high-dose (120 mg/kg) A1AT-treated PiZZ subjects. PP2A activation was assessed in human neutrophils, airway epithelial cells, and peripheral blood monocytes treated with plasma purified A1AT protein. Similarly, lung PP2A activity was measured in mice administered intranasal A1AT. PP2A was silenced in lung epithelial cells treated with A1AT and matrix metalloproteinase and cytokine production was then measured following TNF-α stimulation. Measurements and Main Results: PP2A was significantly lower in neutrophils isolated from PiZZ compared with PiMM subjects. A1AT protein activated PP2A in human alveolar macrophages, monocytes, neutrophils, airway epithelial cells, and in mouse lungs. This activation required functionally active A1AT protein and protein tyrosine phosphatase 1B expression. A1AT treatment acted via PP2A to prevent p38 and IκBα phosphorylation and matrix metalloproteinase and cytokine induction in TNF-α–stimulated epithelial cells. Conclusions: Together, these data indicate that A1AT modulates PP2A to counter inflammatory and proteolytic responses induced by TNF signaling in the lung

Alpha-1 antichymotrypsin gene signal peptide A/T polymorphism and primary intracerebral hemorrhage

Background/Aims: Alpha-1 antichymotrypsin (ACT), a serine proteinase inhibitor, has been implicated in vascular pathology. The TT genotype of the ACT signal peptide A/T polymorphism has been reported to confer susceptibility to primary intracerebral hemorrhage (PICH). We conducted a prospective study to test possible association of ACT signal peptide A/T polymorphism with PICH in a Greek cohort with enough power (80%) to detect a twofold increase in the odds ratio. Methods: We prospectively recruited 147 patients with PICH. ACT signal peptide A/T genotypes were determined in patients and 206 healthy, age- and sex-matched control subjects from the neurology outpatient clinic using the polymerase chain reaction restriction fragment length polymorphism method. Results: Our study did not show an association between ACT signal peptide A/T polymorphism and PICH. We also failed to find any influence on age at onset, the location and volume of PICH as well as on clinical severity at admission or 6-month outcome. Conclusion: Our data failed to confirm an association between ACT signal peptide A/T polymorphism and PICH. However, we cannot exclude the possibility that the TT genotype confers susceptibility at less than a twofold increase. Copyright (c) 2008 S. Karger AG, Basel