A day on Alzheimer's disease

On Friday I attended a series of seminars on Alzheimer's disease at the University of British Columbia's Brain Research Centre. I think the idea was to showcase Canadian research in the field of dementia to woo politicians (also in attendance) and ask them for more funding. We heard about all aspects of Alzheimer's disease, from its history to its treatment, and in this post I will fill you in on the latest developments.

Alzheimer's disease is the number one public health problem in the developed world, with approximately 35 million cases worldwide. In Canada it represents a very expensive problem, estimated to cost 50 million dollars a day. In the time it takes you to read this post, there will be two more people diagnosed with Alzheimer's in Canada. As there are currently no approved treatments that affect the disease itself, there is an urgent need to keep our heads down and power through (bonus points for whoever can identify this reference in the comments) to find a cure.

The first "official" patient with Alzheimer's disease was a 51-year old woman named Auguste Deter. She was examined by Alois Alzheimer in 1901. She suffered from impaired memory, aphasia (a language disorder) and disorientation. Alzheimer kept meticulous records: we have a very detailed description of Auguste's condition, and even a sample of her handwriting (see picture). Even though the condition was described in great detail, Alois Alzheimer did not know what had caused Auguste's disease. Today, as one of the researchers at the seminar pointed out, we still don't know what causes Alzheimer's disease, but on a much higher level.

We do know that one of the main culprits in Alzheimer's disease is amyloid beta (Abeta), a protein that everybody's brain makes. In the brain of an Alzheimer's patient, though, too much of this protein is being made, and it aggregates in toxic chunks called plaques. The researchers present at the seminar predicted that vaccines against these plaques will fail. However, there are several candidate drugs that could prevent or treat these plaques in clinical trials right now.

Interestingly, researchers are also studying naturally occurring compounds: one of the speakers talked about his research looking at whether natural extracts can block the formation of plaques in a "petri dish" model of Alzheimer's (brain cells grown in a dish). He finds that ginger, cinnamon, turmeric, cranberry, rhubarb, blueberry, pomegranate and blackberry all help prevent the aggregation of Abeta. However, he warns that at this point, it is not practical to focus on eating these foods because the concentrations used in the lab are just not possible to recreate in a diet.

Beyond the molecular and biological underpinnings of Alzheimer's disease, researchers are also addressing the inevitable changes the world will need to undergo to accommodate a growing prevalence of dementia. For example, one speaker pointed out that many public places such as airports and even hospitals are very difficult to navigate for cognitively healthy people: this represents a true disservice to people with Alzheimer's disease. Efforts are also being made to engage the public (as to avoid more bad news like this one), and to provide resources for caregivers (such as the fantastic First Link initiative).

Overall, I'm disappointed to report that I didn't learn of any magical intervention that will rid us of Alzheimer's disease, but it's comforting to know that there is a big research community out there who is taking this problem very seriously and who is tackling it from many different angles.

Not-so-subliminal messages

For this week’s post, I had originally intended to kick-off the (Vancouver) cycling season with a post about helmets. So I reviewed the recent evidence to see if I could find an interesting paper. Unfortunately, I ran into a problem of the “boring” kind: the evidence out there is pretty much what you think it is: helmets are good, they prevent injuries. While that’s relevant, it doesn’t make for a great post, because, well, you already know this.

Luckily, I stumbled upon a related story that looks at helmet usage amongst… Fictional characters. The study, published in the journal Pediatrics, looks at safety practices depicted in movies over time. This may seem like a silly waste of time (or the project of your dreams, if you're a grad student), but we know that children tend to imitate what they see in movies (and that is why my eventual kids will never see the “Jackass” movies). Given that by age 18 the average child has spent two years in front of a screen, we might want to know a little more about the kinds of influences they may be getting from mass media.

The researchers started by identifying the 25 top-grossing G-rated (general audience) and PG-rated (parental guidance suggested) US movies for each year between 2003 and 2007. Of those 125 movies, they excluded movies that were animated, not set in present day, fantasy, documentary or not in English. That left them with 67 movies. The researchers then analyzed the safety practices in all the scenes that included characters with speaking roles either walking, driving or riding in a car, driving or riding in a boat, or riding a bike (for a grand total of 958 scenes).

The results show that in movies, just over half (56%) of motor-vehicle passengers wear seat belts, just over a third of pedestrians (35%) use crosswalks, three quarters of boaters (75%) wear personal flotation devices (or lifejackets), and a quarter (25%) of cyclists wear helmets.

Compared with similar studies carried out in the 1990’s and early 2000’s, there is a significant overall improvement in the depictions of safety practices. However, about half of the scenes still show unsafe practices. What’s more, movie characters rarely suffer the consequences of unsafe behavior. How many times did you see someone get up after falling off a cliff and think “Come on!”. The depictions of unsafe behavior combined with the absence of consequences for these behaviors may lead children to minimize dangers in real life, so parents, make sure you point it out when you see characters acting unsafe!

Now the study excluded quite a few movies for simplicity’s sake, and ended up with a fairly small sample, so it would be premature to generalize these results to all movies out there. I would be especially interested in finding out how animated movies fare, since they definitely cater to a younger crowd (Simba sure learned the consequences of *his* unsafe behavior). A later post, perhaps, if such a study exists!

Definitely not the crosswalk!

Reference: Injury-prevention practices as depicted in G- and PG-rated movies, 2003-2007. (2010) Tongren JE et al. Pediatrics 125(2):290-4.

Dogs have owners, cats have staff, and children have rashes

The word "eczema", a skin inflammation that affects 15 to 30 percent of children and two to 10 percent of adults worldwide, is derived from an ancient Greek word that literally means "to boil out". I know firsthand why this word was chosen, as I suffer from contact dermatitis, a form of eczema that is caused by an allergic reaction (to nickel). The itch is not unlike that of bug bites, and this is by far the best depiction I've ever seen of what it feels like to be itchy:

(the ant hill is a nice touch)

As I'm sure you can imagine, having a child with this condition is a bucket load of fun. The ointments, the whining, the scratching, the scabs... (and, in my case, the sowing of little patches of fabric behind *every* jeans buttons... Thanks, mom!). So while eczema is not really a life-threatening condition, researchers are looking into it, because it's very closely tied to parental sanity.

We already know that eczema is not purely genetic: the environment you grow up in can influence your chances of developing the itchy rash. However, what we don't know is what components of the environment play an important role. A recent study attempts to add a piece to this puzzle by researching whether family pets can have an impact on the development of eczema.

Researchers followed over 600 children starting at one year of age. At the start of the study, the parents of each children were asked to fill a survey of their environment, and researchers took a dust sample from each house to test for allergens and such. Three years later, the researchers evaluated which child had developed eczema and which child hadn't, and analyzed what contributing factors might have played a role.

It turns out that owning a dog is not only good for your blood pressure: children who lived in a house with a dog had a significantly lower risk of developing eczema by four years of age. What about cats? The situation was a bit trickier for cats: living with a cat increased a child's risk of developing eczema, but only if the child tested positive on a cat allergen sensitivity test (the skin-prick kind).

So get rid of Mittens and adopt Fido? Not so fast. First, these findings don't hold true for all allergy-related conditions. For example, dogs are thought to contribute to asthma. Second, what this study really does is highlight how complicated these conditions are: several different types of environmental exposures may impact allergies in different ways, so it's very hard to draw clean, straightforward conclusions and guidelines.

That said, I'm still going to blame my eczema on growing up in a dogless home. I wish I would have known this tidbit of information way back when I was a kid: it might have helped me in my campaign to get a pet (admittedly, my heart was set on a horse).

A healthy start!

Reference: Opposing effects of cat and dog ownership and allergic sensitization on eczema in an atopic birth cohort (2010) Epstein TG et al. Journal of Pediatrics [Epub ahead of print].

New Year's resolutions through delayed gratification

It's that time of the year. That I-will-eat-better-and-exercise-lots time. It's that time when we kick start New Year's resolutions with the best intentions, the best plans, the most motivation. Unfortunately, and I can tell you this from experience, some of us will fail. A recent article published in the journal Obesity sheds light on one important aspect in keeping some resolutions: delayed gratification.

Delayed gratification, as the name implies, refers to the ability to forgo an immediate reward (for example, delicious Cheesy Poofs) for a benefit that will come later (for example, rocking that little black dress). A lot of research shows that the better you are at delaying gratification, the better you do in life in general (you may have heard of the famous marshmallow study). To see if delayed gratification is linked to obesity, a team of researchers set out to test whether children who have a high body mass index (BMI) are less likely to delay gratification.

The researchers looked at data from an educational obesity intervention program. In this program, attended by obese or overweight children along with their siblings (the healthy weight control group), children earn a point if they complete their weekly goals. They then have two choices: either spend that point immediately on a small toy prize (like a pencil) or save the point to use later on a larger prize worth more than one point (like a basketball). The measure of points saved and points spent is thought to be a valid model of delayed gratification. So the researchers looked at the relationship between how many points were saved by a child and that same child's BMI. The results show that a higher BMI is associated with less points saved, meaning the children who were overweight or obese had a harder time delaying gratification.

The strong aspect of this study is that the rewards were not food-related. This allowed the researchers to study delayed gratification as a behavior trait in general, and not specifically as it relates to obesity. However, their sample was fairly small (59 children) and the duration of the study was fairly short (12 weeks). Therefore, it's difficult to say whether delayed gratification plays a role in weight loss.

Overall, the research is relevant in that it suggests that working on delayed gratification (it's possible to "train" to get better at it) may help in obesity interventions. And for all you out there with eat-less-exercise-more resolutions, all I can say is "eyes on the prize"...

Reference: Ability to delay gratification and BMI in preadolescence. (2010) Bruce, AS and al. Obesity [Epub ahead of print].

The year in review

As the year draws to an end, it’s time to compile the exciting discoveries that marked 2010. Here is a snapshot of my top 5, in chronological order:

Study #5: Communicating with the minimally conscious

In a nutshell: An imaging technique, functional magnetic resonance imaging (fMRI), allowed researchers to communicate with patients in a vegetative state. Researchers asked yes/no questions, and the patients answered by thinking of playing tennis for yes or thinking of a house for no. The resulting brain signals from these thoughts could be imaged, interpreted and used for communication.
The good: This technique gives great hopes for friends and relatives of patients in minimally conscious states.
The bad: The study was heavily criticized: only one patient was tested, and the technique is far from perfect.
What’s next? We will no doubt hear more about this in the near future. The first step will be to replicate these findings with a greater number of patients.

Study #4: The synthetic cell

In a nutshell: Researchers made synthetic DNA and incorporated it into an empty bacterial cell, thereby creating a fully functioning cell with a man-made genome.
The good: This study represents a technical feat and opens new doors in the fields of molecular and cellular biology.
The bad: Like transgenic organisms before this, the synthetic cell re-opens the Pandora box of ethical questions.
What’s next? Human-engineered cells will probably play a role in gene therapy and in the quest to build tissue in a dish.

Study #3: Brain training doesn’t work

In a nutshell: A study of computerized brain training using over 11,000 participants showed that people improved at the tasks they practiced, but this improvement didn’t extend to general cognition.
The good: This study urges caution when buying into the brain training craze.
The bad: The results may be misleading: it’s not because the researchers didn’t see any improvement that there weren’t any. The brain training could have been inadequate or the researchers could have been measuring the wrong parameters.
What’s next? More controlled studies will be needed to determine the effectiveness of the games. Brain training is likely to become increasingly specialized: training for older adults, for children with autism, etc.

Study #2: Optogenetics

In a nutshell: Researchers were able to control brain cells using light, and rescued symptoms of Parkinson’s disease in mice.
The good: I said it before and I’ll say it again: optogenetics has the potential to revolutionize medicine.
The bad: The technique is quite complex and difficult and so far only possible in small mammals.
What’s next? Researchers are already testing in larger mammals and developing new ways to deliver light into the brain.

Study #1: The slut gene

In a nutshell: Researchers found a relationship between a specific version of a gene and promiscuous sexual behaviors.
The good: The study provides new insights into the link between genes and human behavior.
The bad: It’s not that simple.
What’s next? You can expect more studies of the “this gene does that” type. However, researchers are increasingly interested in how the environment can impact the expression of genes, and the story is bound to get even more complicated.

Looking forward to more gems in 2011!

Happy New Year!

Prozac for puppies

Separation anxiety isn’t just for babies anymore: one in two dogs is thought to suffer from separation-related behaviors when their owners leave the house. These behaviors take many forms, from chewing your favorite pair of Jimmy Choo’s (Santa Baby… I want Jimmy Choo’s) to yapping uncontrollably until the neighbors call the police. Seeing as this may represent a serious problem in animal welfare, a team of researchers assessed the relationship between separation-related behaviors and the overall moods of dogs.

The researchers used 24 shelter dogs and started by measuring whether each dog suffered from separation anxiety. To do this, a researcher played with a dog for 20 minutes in a designated room. The next day, the dog was taken to the same room, played with for a few minutes, then left alone for five minutes. The dog’s behavior during those five minutes was analyzed and graded as a “separation anxiety score”.

A few days after the test, the researchers conducted another experiment to assess whether each dog had a pessimist or optimist outlook. In order to achieve this, they trained the dogs to learn that when in a given room, a food bowl placed at the very left of the room always had a treat in it, and a food bowl placed at the very right or the room never had a treat in it. Once the dogs learned this, the researchers placed a food bowl right in the middle of the room. Presumably, dogs that ran fast to see if this new bowl has a treat in it were anticipating that it had food in it and were considered to be “optimistic”, whereas dogs who either slowly made their way over or didn’t bother to check it out were considered to be “pessimistic”. It’s kind of a dog version of the glass half-full or half-empty paradigm.

The relevant finding of this article is that the researchers found that dogs who experienced separation anxiety were more likely to be of the “pessimistic” kind. Pessimism is thought to be related to negative moods, and knowing this may help in figuring out how to avoid chewed-on Jimmy Choo’s.

While I thought the study was quirky and interesting, I found it a bit of a stretch to label these dogs as optimistic or pessimistic using such a simple experiment. The researchers themselves owned up to this by saying that “the conscious experience of such a state [optimistic/pessimistic] cannot be known for sure”. When I read the article, I thought maybe the dogs who went for the food bowl in the middle were just more curious than others, and I’m not sure how curiosity relates to optimism (for example, I consider myself to be quite curious, but not necessarily optimistic: I browse the Jimmy Choo website to see what the new styles are, but I don’t envision ever owning a pair). As well, I thought the measure for separation anxiety was a bit weak. While it’s a known experiment, it’s not immediately obvious to me that the behavior of these pound dogs relates to the behaviors you would observe in dogs with a stable home.

Still, it’s a good reminder to keep our pets as happy as possible, especially during the holidays when routines are broken and moods are uneven.

Reference: Dogs showing separation-related behaviour exhibit a “pessimistic” cognitive bias (2010) Mendl M. et al. Current Biology, 20(19):R839-40.

Food for thought on thoughts for food

Christmas party season is officially upon us. The next few weeks are pretty much going to be a long string of turkeys, stuffing, various things made with cranberries and cutesy Christmas cookies à la Martha Stewart. Faced with this, many of us who are concerned with staying trim and not slipping into food comas on a daily basis may be feeling a little apprehensive. Well, fear not! New research published in the journal Science suggests you can eat less by simply… Thinking more about food!

The study looks at the relationship between the concepts of mental imagery (imagining doing things) and habituation (getting used to things). Through mental imagery, imagining things can affect your body and your emotions just as much as the real thing: just thinking about a spider crawling on your neck can lead to the same feeling of tingling and fear as if it was actually happening. The second concept, habituation, refers to the decrease in your body and your mind’s response to a stimulus. For example, your tenth bite of stuffing is not nearly as satisfying as your first. Given these two principles, the researchers asked if you could habituate to a food just by imagining eating it.

The participants in the study were divided into two groups and each group was asked to imagine doing a task. The first group was asked to picture eating 30 M&M’s, one at a time. The second group was asked to picture putting 30 quarters into a laundry machine, one at a time. After this mental imagery task, the participants were each put in front of a bowl of M&M’s and told to eat as much as they wanted as a preparation for a “taste test” later on (obviously, the taste test is fake, it’s just an excuse to get the participants to eat). The researchers then weighed the leftover M&M’s and measured how much each participant had eaten. They found that those who pictured eating M&M’s ate significantly less candies than those who pictured feeding a laundry machine!

The researchers then compared participants who imagined eating only three M&M’s with participants who imagined eating 30. They found that participants who imagined eating more M&M’s ended up actually eating fewer of the real ones. This means that habituation (doing something repeatedly) is key to observe an effect of mental imagery.

So whether your drug of choice is M&M’s, stuffing or cheese balls, you may be able to minimize the holiday damage by doing a little mental exercise. Now if only I could just picture purchasing and wrapping a bunch of presents…
Reference: Thought for food: imagined consumption reduces actual consumption. (2010) Morewedge CL et al. Science 330:1530-1533.