Alzheimer's Disease & Caffeine & Blood Brain Barrier Baste on 18 Apr 2008 10:25 pm
Coffee: Food for Thought?!
Source: J Neuroinflammation (2008), 5: 12 (open access)
Article Type: Original Research
Authors: X Chen et al.
A morning without coffee is unthinkable for me. And especially during the day in the lab I need the regular ‘perfusion’ with the black gold. A habit, which - based on the latest publication by Chen et al. - might not be that bad at all for me.
One of the earliest symptoms experienced by Alzheimer’s disease (AD) patients is olfactory dysfunction. The olfactory bulb is characterized by an intact blood brain barrier (BBB) that can get disrupted, e.g., when ingesting a high-cholesterol diet.
When testing such a diet (2% cholesterol) in rabbits, Chen et al. found that the daily administration of 3mg caffeine in the drinking water for 12 weeks “blocked high cholesterol diet-induced
* increases in extravasation of IgG and fibrinogen,
* increases in leakage of Evan’s blue dye
* decreases in levels of the tight junction proteins occludin and ZO-1
* increases in astrocytes activation and microglia density where IgG extravasation was present.”
“Our observations that caffeine had no effects on plasma levels of total cholesterol and HDL indicate that caffeine protects against high cholesterol diet-induced disruption of BBB downstream of cholesterol.”
“The protective effects of caffeine against high cholesterol diet-induced increases in BBB disruption might happen at the BBB per se, and the protective effects of caffeine against high cholesterol diet-induced increases in the density of astrocytes and microglia could be an indirect consequence of its protective effects against BBB disruption. On the other hand, it has been shown that caffeine (and adenosine) can regulate neuroinflammation in in vitro models devoid of BBB. Therefore, the protective effects of caffeine against high cholesterol diet induced increases in astrocyte activation and increases in density of microglia might parallel its protective effects against BBB disruption.”
From a practical point of view it is interesting to note that “the dose of caffeine (3 mg/day) used in this study for 3 to 4 kg rabbits is equivalent to an adult human weighing 70-80 kg consuming a single cup of coffee and is far less than the average caffeine consumption in the USA and Canada that is about 200 mg per person per day.”
The provisional PDF can be downloaded here.