AP Biology class blog for discussing current research in Biology

Tag: stroke

Mouse Gut Research Could Save Your Brain

A new study in mice published by Nature Magazine suggests that a specific microbial balance results in a reduction of brain damage after a stroke. The severity of a stroke is determined by two types of intestinal cells: Regulatory T Cells and Gamma Delta T Cells. Regulatory T cells have a helpful inflammatory effect. However, Gamma Delta T Cells make a cytokine which results in harmful post-stroke inflammation.

Researchers at Weill Cornell Medical College and Memorial Sloan Kettering Cancer Center studied two different groups of mice in order to learn if gut cells could be altered in order to reduce stroke severity. One group of mice had gut bacteria that was unaffected by antibiotics, while the other group of mice’s gut bacteria was extremely vulnerable to antibiotics. The group of mice that was vulnerable to antibiotics had a higher ratio of good Regulatory T Cells to harmful Delta T Cells.

House mouse.jpg

The researchers then induced strokes in all of the mice, and the brain damage was 60% less devastating in the mice vulnerable to antibiotics than the other group. In order to ensure that the difference in stroke severity was solely as a result of the gut bacteria, the researchers took the feces of the mice with reduced stroke severity, and transplanted it into new mice. Those new mice also exhibited a resistance to brain damage, confirming the belief that the gut bacteria was responsible for the change.

These new findings in the research of mice may be able to benefit humans in the future. Antibiotics or a specific diet may be able to reduce the effect of stroke on the brain. However, the gut microbiome of a mouse is vastly different than the gut microbiome of a human, so it may be a while before new treatments are discovered.

Daylight Hurting Time?

New studies have found that daylight savings time might do more hurting, than saving.  Apparently, changing human’s circadian rhythm (aka theiScreen Shot 2016-02-29 at 11.29.23 PMr sleeping cycle) can lead to higher risks of stroke. It raises the risk of a specific type of stroke, an ischemic stroke. An ischemic stroke is when blood clots block blood vessels that carry blood to the brain.  The risk of getting a stroke during or around daylight savings time was 8% higher for the average person. Cancer patients have a 25% increase and people over the age of 65 have a 20% increase after the time change.

Though these increases may be small…. they are still increases and that is significant. All problems root with changing the circadian rhythm; it controls the regulation of most of the daily routine. Throwing off a sleep schedule is never good because no one likes to be tired, however it’s possibly more dangerous than we originally assumed. I believe sleep is one of the most rejuvenating things and not something that should be messed with, therefore I agree that if daylight savings causes problem… it’s doing more hurting than saving.

Main Article:

For further information:

Low Iron, Sticky Blood, and Strokes

Photo taken by BruceBlaus

Photo taken by BruceBlaus

Scientists at Imperial College London discovered that low iron levels make blood “stickier” and thus, result in a higher risk of having a stroke.  The most common type of stroke, ischaemic stroke, is a result of a lack of blood supply to the brain caused by small clots.  These researchers found that iron deficiency increases stickiness of platelets, which cause clotting when stuck together (original article).  This connection between iron deficiency and stickier blood was made previously, but its implications are just now being identified.

In this recent study, about 500 patients with a disease called hereditary haemorrhagic telangiectasia (HHT) were studied because their condition allows small blood clots to travel to the brain more often than clots in people without the condition.  The patients with low iron were more likely to have a stroke, and their platelets stuck together to form a clot more quickly than those of patients with higher iron levels.  More specifically, having a moderately low iron level (about 6 micromoles/liter) about doubled the risk of stroke when compared to the risk with a normal iron level.  This is a strong start to proving the link between iron levels and strokes, but more research must be done to fully prove the connection because there are more steps that occur between the clot forming and the stroke occurring.

Scientists are hoping that the newly discovered implications of this research could help lower the risk of stroke in high-risk patients through the monitoring and regulation of iron levels.  Could simply raising a person’s iron level help prevent strokes? I believe that further research will reveal a more complex solution involving a process that occurs between the clotting and the actual stroke.

SALT: Hate it or love it? Either way you can blame your parents.

Some Rights Reserved:

As a salt hater myself, I find it hard to understand why my grandmother pours salt over salads, soups, even “bland” sandwiches. Why she seasons all her food so that it tastes like salt water was always a mystery to me.

So why DO some people like salt while others hate it?

The answer may lie in what parents feed their children between the ages of two months and six months- sometimes unknowingly giving their children food with lots of salt.
According to the study, infants who ate only baby food and other natural foods like fruits and vegetables (all of which contain little or no salt) during their first six months disliked or were indifferent to salty foods by preschool age. On the other hand, the children who had consumed salty foods in infancy preferred salty foods over food without salt. Unfortunately, these children tended to adore unhealthy, salty foods like potato chips, French fries, hot dogs and pretzels.

The good thing about consuming salt is that it is necessary for humans to function properly.
For example, humans need salt to make the digestive acid, hydrochloric acid. Also, oftentimes it is mixed with iodine – another element necessary for human life. In the late 900’s, salt was worth its weight in gold in many African kingdoms simply because it is so vital.

So how much salt is too much?

On average, a person needs to consume about 500 mg
day. However, most americans consume ten times that amount.

We Americans have trouble consuming too much salt. Too much salt can lead to hypertension and heart attacks. Normally, the kidney filters the blood so that excess salt will be released in the urine. However, when people eat huge amounts of salt, some of the excess remains in the bloodstream. For some people, the increased salinity in the blood causes blood pressure to rise to unsafe levels. Unsafe because, as we learned in class, hypertension can lead to heart attacks and strokes.

So, for most babies it is better when the parents stick to low sodium foods, especially since the infants showed no preference for salt at two months, meaning that my grandmother, and other “salt lovers” probably aren’t born with their love of salty foods. Salt “loving” seem to be a behavior that, once moulded between the ages of 2 and 6 months, has lasting effects on that person’s preferences.


Main Article:

Powered by WordPress & Theme by Anders Norén

Skip to toolbar