BACKGROUNDS: Increase in SP release as a function of hypoxia of the rat carotid body is a tissue response to ischemia that leads to neurogenic inflammation and cognitive deficits. Substance P-mediated inflammation is reported to attenuate the neuroprotective PPAR-gamma. This study was undertaken to investigate the effect of aprepitant, a substance P-NK1 receptor antagonist in bilateral carotid artery occlusion (BCCAO)-induced ischaemic brain injury and vascular dementia. METHODS: Bilateral carotid artery occlusion was performed in Wistar rats to produce hypoperfusion and ischaemic injury. Dementia was noted by an increase in brain acetylcholinesterase (AChE) activity, and attenuation of learning ability (escape latency time) and memory retention (time spent in target quadrant) using Morris water maze. Oxidative stress was estimated by an increase in thiobarbituric acid reactive substances (TBARS) level and a decrease in reduced glutathione level. Vascular dysfunction was measured by attenuation of acetylcholine-induced endothelium-dependent relaxation (isolated carotid ring preparation), and increased in carotid artery TBARS level. Neurodegeneration was assessed in the hippocampus by H&E staining. Aprepitant and donepezil (positive control) were administered to rats from day 28 to day 42 after BCCAO. RESULTS: Aprepitant (20 and 40 mg/kg) and donepezil (2 mg/kg) significantly improved vascular function, learning and memory ability, and decreases the neuronal cell death, oxidative stress, and ache in BCCAO rats. Donepezil effect was more significant than the low dose of aprepitant on disease markers. However, BADGE (30 mg/kg a, PPAR-gamma antagonist) prevented the ameliorative effect of aprepitant. CONCLUSION: Thus, it may be concluded that aprepitant attenuates vascular dysfunction and dementia in BCCAO rats by activating downstream PPAR-gamma.
BACKGROUND: A large number of observational epidemiological studies have reported generally positive associations between circulating mass and activity levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA2 markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors. OBJECTIVES: By combination of data from individual participants from all relevant observational studies in a systematic 'meta-analysis', with correction for regression dilution (using available data on serial measurements of Lp-PLA2), the Lp-PLA2 Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA2 with coronary heart disease (and, where data are sufficient, with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA2 and cardiovascular outcomes. METHODS: A central database is being established containing data on circulating Lp-PLA2 values, sex and other potential confounding factors, age at baseline Lp-PLA2 measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA2 will yield information on a total of about 15 000 cardiovascular disease endpoints.
