Red wine in a pill: Metabolic effects of resveratrol in humans

Remember back in July I talked about a future where simply popping a couple of resveratrol tablets gave the same benefit as a walk around the block?  That future may be closer than we think!  A recent paper in the journal Cell Metabolism describes the results of a very small study of resveratrol in humans and the data is pretty exciting.  Let me repeat that caveat... this was a small study!  Still, the metabolic effects described in this work clearly emphasize the need for further research on this and other magical polyphenols.

The paper published by Timmers et al. (abstract) is the first to study the metabolic effects of resveratrol (RES) in a clinical setting.  Eleven obese men were given either RES (at 150mg/day) or placebo for 4weeks, followed by a 4-week washout and then the treatment was switched (this is known as a crossover study).  Patients and doctors were both blind as to what treatment was being administered and during treatment, a variety of metabolic tests were conducted.  There is a lot of data in the paper (and it looks like the pdf is free, so check it out yourself!) but let me hit a few highlights:

1) Patients taking RES show an increase in mitrochondrial efficiency, particularly in fatty acid oxidation of muscle fats, and decreased levels of triglycerides and glucose levels.  Significantly, these changes are seen at the gene level, suggesting that it is the overall metabolic pathway that is improved, not just a downstream clearance of metabolic markers.  A similar pattern of changes has been noted in athletes undergoing endurance training (they reference Dube et al, 2008 and Meex et al, 2010).  This is fairly consistent with the Momken paper I blogged about back in July, ie, RES acts like an exercise mimetic.

2) Changes in glucose and insulin levels are modest.  Timmers et al. report a statistically significant drop in serum glucose and insulin levels in the patients taking RES, but this effect is pretty modest.  There is also a shift in peak glucose and insulin levels after a liquid test meal, suggesting some changes in glucose homeostasis, but they could not draw definitive conclusions.  If you recall, the rat data from Momken et al. was also pretty weak with regard to insulin/glucose levels.

3) RES also showed other health benefits:  This study also demonstrated a significant effect of RES on lowering systolic blood pressure and mean arterial blood pressure, as well as decreases in resting energy expenditure and sleeping metabolic rate.  The later two effects are also seen in studies of calorie restriction and further illustrate the metabolic changes induced by RES.  Calorie restriction is also associated with increased lifespan in animals, so these observations may be pointing to another possible health benefit of RES.  They also observed a decrease in markers of inflammation, further suggesting an overall improvement in health. Although this is interesting, I still think the catechins are the more potent player here... I'd like to think that as the flavinoids polymerize during aging, the wine gets better and better for your heart. It would be interesting to see how some of these molecules perform in a study similar to this.

Taken together, this paper highlights some of the metabolic effects of RES in humans and may offer some insight into the health benefits of this polyphenol.  Much like the rat study, however, this is a very high dose (the equivalent of >100 glasses of wine per day) and so who knows if there are long term side effects at this dose.  The fact that they see statistical significance with only eleven patients is also very surprising.  Clinical studies usually need hundreds, or even thousands of patients to provide enough statistical power to draw conclusions like this.  Personally, I would find taking a pill much less satisfying that enjoying a nice glass of Cabernet. Since that glass of Cab is a veritable grab bag of Redox goodies, I think it is also very likely that there are many other 'good' polyphenols in wine that scientists haven't studied as rigorously as RES.  So as dozens of trick-or-treaters descended upon our neighborhood on Halloween night, I had to raise my glass to our ancient ancestors who discovered the wonderful winemaking process, and the scientists who now try and tease apart how it does what it does. I may have also stolen a chocolate or two... in the interests of science, you know.

Halloween winemaking magic at Bruliam Wines

Just in time for Halloween, Kerith Overstreet at Bruliam Wines has a great blog post this week about working with her spooky 2011 harvest (beating it into submission, actually).  Sounds like a challenging year!  She describes the redox chemistry that goes on during the early fermentation process and actually has a graph from her lab!  I first blogged about the magic of winemaking after Kerith's great talk on the subject (here is my post) and even she refers to the process as magic in her latest post (but she also refers to wife swapping, Alanis Morissette, and Hanukkah miracles, so who knows what state of mind she was in as she wrote this).  Anyhow, a very fun, informative read directly from the mysterious front lines of winemaking.  Enjoy it with a glass of good Cabernet, the official wine of the dead.

Keriths latest blog post:  (link)

21st Century mummy

Just a quick pointer to a cool article on a recent attempt at mummification (here's the link). Stephen Buckley, a chemist at York Univeristy in England, has spent two decades studying how ancient Egyptians made mummies.  He studied tissue samples and chemical traces left on canopic jars in an effort to reproduce the method.  He then tested the process in his shed, using pig's legs as a proxy for human flesh (there's a DIYbio project for you!).  I'm not sure if this guy is married, but even here in the Dark Lab, this work would be pushing the limits.  Anyhow, this year he felt that he was ready for prime time.  He placed an ad looking for suitable volunteers and the lucky person was... Alan Billis, a London cab driver.  Terminally ill with lung cancer, he went through the mummification process after he died. By all accounts, it was a success and the body will be kept for at least a year to study.  Hopefully, Alan is hanging out with a bunch of cool, Egyptian princesses.  Thousands of years from now, archaeologists will argue over whether our society placed a high value on cab drivers, or if Mr. Billis was simply a member of the ruling elite.  They will come up with grand theories on how he lived, how he died, and why he was the only surviving mummy of the period.  Should make for an interesting read.



Cat mummy at the British Museum (link)



To me, it is truly amazing that with all of today's technology, it is difficult to reproduce the mummification procedure.  The Egyptians likely had years of empirical data to build from and since it was considered a sacred ritual for the upper class, there was significant motivation for young priests to be good at making a mummy.  I can see a room full of young mummification interns, trying to preserve rats or some other suitable test animal.  After months of work, the mentor unwraps the package, only to find a rancid, decomposing corpse. "Aw, man," the student whines (or whatever the angsty teen expression was at that time).  He then slouches his way over to the stone quarry.

A gene important for creating zombie caterpillars

Advancements in zombie science are coming fast and furious!  An email from a colleague (and fellow reader) noted that I missed a recent article in the journal Science concerning zombies.  The article, titled "A Gene for an Extended Phenotype", seemed pretty innocuous, however, after going back and reading it more carefully it turned out to be a pretty cool discovery.

First, a bit about zombie caterpillars.  There have been several documented reports of zombie-like behavior in moth larvae.  This report is focused on the infection of the gypsy moth (Lymantria dispar) by a baculovirus (known as LdMNPV).  During the various stages of molting, larvae typically hang out on the ground and away from The Very Hungry Birdie, but climb up into the trees at night to feed on leaves.  After infection by the baculovirus, their behavior changes (noticing a pattern here?).  As the virus replicates and ravages the inside of the caterpillar, the infected host climbs up into the leaves during the daylight hours and eventually dies.  The body then liquefies, and virus-laden particles rain down on the uninfected victims below.  Yeah, you can't script horror much better than that.

Ok, so Hoover et al. (from Penn State, see abstract) were interested in identifying which genes were important for the change in behavior.  To do this, they infected caterpillars with wild type baculovirus, as well as virus that had been genetically engineered to be missing certain genes.  The caterpillars were placed in 1 liter soda bottles equipped with a fiberglass screen for climbing (in true DIYbio fashion!!).  Interestingly, when a gene called egt was removed, the caterpillars died at ground level, suggesting that the behavioral control of the virus had been altered.  To make sure it wasn't an artifact of the mutated virus, they re-engineered the mutated constructs so that the egt gene was present again and the zombie caterpillars climbed up the mesh and died.  It would appear that the egt gene in the virus has evolved to make the caterpillars engage in high-risk behavior, and to place the caterpillars in a location where rain/gravity/hungry birdies can maximize viral spread. Genius.

The next step is to figure out the mechanism.  Interestingly, Hoover et al. mention that the egt gene encodes an enzyme which deactivates a hormone (20-hydroxyecdysone) involved in the process of molting.  It is intriguing that the virus blocks the molting process in order to give itself time to replicate inside the host, but it was hard for me to understand how the modification of the hormone leads to behavioral changes.  Perhaps entomologists already know that part.  Coincidentally, the hormone is also reported to have a variety of biological effects in humans, even though we do not molt and lack the endogenous receptor. What would the modified enzyme do in a human?  Until we find this stuff out, it's probably a good idea to check the trees around your house, particularly if you hear a dripping sound... and if your neighbor has been missing awhile.

Yes, there are zombies all around us.

Biopunks help solve structure of key viral enzyme

I've been meaning to blog about the program FoldIt for some time.  It's a program out of David Baker's lab (link to University of Washington) where users can manipulate protein structures to improve folding but in a unique twist, the improvement is 'scored', just like a game.  A problem is posed on the website and thousands of players compete to see who can find the best solution. They also have regular competitions to see how well players can predict the structure of a protein from just the amino acid sequence (the Holy Grail of the protein folding world).  I've played on and off for a couple of years and it's pretty fun... but it's a lot like my day job, so if I take the time to play a video game it is usually something like Rock Band.  Still, FoldIt is a pretty easy game to play (the number of rules is limited and the GUI is very intuitive) so the real challenge is in the player's ability to use logic and their skill in 3D visualization. I'll have a more detailed post about it and its less-familiar cousin EteRNA (the RNA equivalent of FoldIt) later. When you are ready to play, click here (it's free, easy, and fun... really!)

This week in the journal Nature Structural and Molecular Biology (I have had several rejection letters from this fine journal) is an article (abstract) describing the use of FoldIt to solve a scientific problem at least ten years old!  Crystallographers have been trying to determine the structure of the monomeric form of MPV protease. MPV stands for Mason Pfizer Virus, a virus that causes an AIDS-like syndrome in monkeys.  Although it is not HIV per se, the protease is a key enzyme in the production of a mature virus and so developing drugs using this structure could be useful in developing an HIV therapy.  This protein was one of those rare cases where good crystals could be grown but interpreting the x-ray data back into the final 3D picture of the protein could not be done. So, researchers looked to crowd-sourcing as a means to solve this problem.  For three weeks, FoldIt players had the chance to optimize a 3D model, based on an NMR structure of the monomer.  Teams competed to see who could come up with the best solution (based on how well the different structural pieces of the protein fit together).  After all that tweaking and optimizing, more than a million different models were created.  Crystallographers used the best of these models as a starting point and one of them successfully generated a solution to the x-ray data using molecular replacement.

Who were the people who provided the key to success?  The top groups were listed as co-authors by their team name (FoldIt Contenders Group and FoldIt Void Crushers Group) and by a few handles listed in the article (spvincent, grabhorn, mimi) so not much is known about these folks, but I'll bet many of them had no knowledge of crystallography or biochemistry and probably had no clue what this enzyme did.  However, the fact that thousands of players worked together on this problem and were ultimately successful highlights the power of crowd-sourcing and that top-flight science can be accomplished through a "game".  I think this paper will also motivate others, both players and scientists, to leverage the power of biopunks!

How about a GFP cat to go with your GFP beagle?



The GFP cat:
From Figure 2 of Wongsrikeao et al.



Well, that didn't take long.  I blogged last month about a paper describing GFP beagles that were able to glow under the control of a tetracycline promotor.  Now, a new Nature Methods paper describes a GFP cat!  The basic point of the paper (here's the abstract) was to demonstrate gamate-targeted transgenesis in cats and to use this ability to make a transgenic feline model for HIV research.  The HIV part was interesting, as they introduced the gene for a protein from the rhesus macaque known as TRIM5.  I studied TRIM5 pretty extensively when I was doing HIV research as it is a species-specific restriction factor that is effective at stopping HIV replication.  Cats don't have an analogous TRIM protein (that we know of) so by introducing this protein into the cat, researchers can study the transmission of FIV (the cat version of HIV).

The cool part was the GFP expression.  Wongsrikeao et al. wanted to see if they could introduce multiple genes, and since GFP is a convenient marker, they could also study the presence of the transgenes in progeny cats.  As I mentioned in the Beagle post, fluorescent proteins have been introduced in animals previously (see here and here for cats) but the efficiency in the present work is better.  I'm certainly no expert on transgenics, but the general trend over the last few years is clear... we are moving from the realm of the nearly impossible to the land of the challenging but doable.  Glowing cats, dogs, hamsters, bunnies, you name it are going to be popping up in your pet store relatively soon.  Lost your dog?  No problem... just look for the glowing blob in the woods.  How about a government program to develop a GFP opossum?  Think of how much road kill would be eliminated if you could see these animals before they got up close and personal with your tire.  Think about how cool the forest would be if all of the little woodland creatures glowed bright green. Think about how easy it would be to hunt.  I wonder how screwed up the food chain would get. I guess we would have to make GFP plants for the little GFP bunnies to hide in. Man, this would make a really cool dystopian/biopunk story!

Can gut bacteria make zombies?



L. rhamnosus: Not a zombie-
producing bacteria...yet.



If T. gondii weren't enough to worry about, now there is evidence that bacteria in our gut can influence brain function.  Lactobacillus and other probiotic organisms have long been speculated to have beneficial in vivo effects, and are most commonly known for improving the health of the digestive tract.  L. acidophilus is probably the most widely known, since it is used to make yogurt, but there are many other types of lactobacilli with alleged health benefits ranging from lowered cholesterol to improved mood.  Some of these benefits are speculative, and for many years any benefit (such as improved gut health) was thought to be due to local effects or secreted chemicals.  However, the impact of these bacterial colonies may be much more far-reaching.

A Proceeding of the National Academy of Sciences (PNAS) paper published by Heujtz et al. last January (abstract) showed that microbial colonization in the mouse gut led to the activation of signaling pathways involved with motor control and emotional response.  This was the latest in a growing body of literature that suggests gut bacteria could influence how we think and act.  Now, in the August edition of PNAS, Bravo and colleagues take this one step further (abstract).  They show that Lactobacillus rhamnosus can directly influence the expression of GABA receptors in the brain.  GABA is the primary neurotransmitter for regulating many physiological and psychological activities in humans.  For example, caffeine inhibits GABA and results in an overall increase in neurotransmitter activity.  In contrast, alcohol and sedatives tend to increase GABA activity, leading to reduced neurotransmitter activity. Bravo et al. showed that feeding mice L. rhamnosus reduced GABA expression in some areas of the brain, while increasing it in others.  The overall effect was to make the mice more calm.  Here in the Dark Lab, we would test this by subjecting the rats to endless episodes of Jersey Shore, Barney and Friends, and The Jonas Brothers, and then asking how long it takes before they fall into convulsions.  Bravo measured stress-induced hyperthermia (rise in core body temperature from stress) after a battery of different tests, including  forced swimming and mazes (less barbaric than listening to the Barney jingle, but presumably effective at producing stress) and showed that the L. rhamnosus-fed animals exhibited less stress during these activities.

The final point of the paper was what I found most interesting.  Some of the animals had the vagus nerve cut prior to the start of the experiment.  This nerve is a direct link between the gut and the brain and is responsible for transmitting signals about hunger and satiation.  In these animals,there was absolutely no effect from consuming L. rhamnosus.  No changes in GABA expression and no behavior changes versus the control animals.  This means that the probiotic bacteria that colonize in the gut might actually use this nerve to signal directly to the brain.  Although these bacteria appear to provide a health benefit, I can certainly imagine other strains that are more nefarious.  Yeah, I'm talking about zombies again.  This phenomenon is not all that different from what is seen in T. gondii or the zombie ants... microbial agents that manipulate the brain function of the host.  If a probiotic strain can mimic the effect of caffeine-overstimulation or, even worse, caffeine-deprivation, then that would be a whole new kind of scary.  Anyone who has seen me before that first cup of coffee knows what I'm talking about... it's bad enough to give a zombie nightmares!