Imagine if just walking around or getting up out of a chair was painful. This is the case for many people with arthritis—a family of joint diseases that cause pain and stiffness
By far the most common kind of arthritis is osteoarthritis, an age-related disease. This means that we can expect more people to suffer from the disease as Canada’s population continues to get older.
While the number of people with arthritis is increasing, it is difficult to know exactly why. There are a number of risk factors for the disease beyond age. Thus, the odds of a millennial developing arthritis may not necessarily be the same as a baby boomer at the same age. Factors that increase risk such as smoking and obesity, as well as factors that reduce risk such as income and education, change over generations.
To determine what risk factors are associated with arthritis prevalence across generations, Krembil Senior Scientist Dr. Elizabeth Badley and colleagues examined 16 years’ worth of health data from the Canadian National Population Health Survey. They looked at arthritis prevalence and risk factors across four generations: the World War II “silent” generation (born 1935-1944), baby boomers (1945-1954 and 1955-1964) and Generation X (1965-1974).
The team found that arthritis is more prevalent in recent generations—and on average, recent generations are also getting the disease at a younger age. An important factor that predicted the increasing prevalence of arthritis was obesity. Even though recent generations are on average better educated, richer and smoking less than previous generations, which should be associated with less arthritis, they are also getting heavier which has largely cancelled out these advantages.
“Our understanding of the impact of weight on arthritis prevalence trends is likely to be an underestimate,” comments Dr. Badley. “Arthritis prevalence may increase faster than previously believed as our population not only ages, but experiences increasing levels of obesity.”
The differences between generations also highlight the need for arthritis management and education programs aimed at reducing obesity and other risk factors in young and middle-aged adults. These programs would help counter the earlier onset and increasing rates of arthritis experienced by those in Generation X and future generations.
This work was supported by the Canadian Institutes of Health Research and the Toronto General & Western Hospital Foundation.
Badley EM, Canizares M, Perruccio AV. A population-based study of changes in arthritis prevalence and arthritis risk factors over time: Generational differences and the role of obesity. Arthritis Care Res (Hoboken). 2017 Mar 8 doi: 10.1002/acr.23213
An at-home sleep apnea test will be available to Ontario patients for the first time as the result of a unique MaRS program.
BresoDx, a portable test for sleep apnea, is the first technology to complete MaRS EXCITE, an innovative initiative that accelerates the adoption of health technology in Ontario.
The breakthrough medical device, developed by BresoTec, will be rolled out to select clinics in the province. BresoDx offers a patient-centred option for sleep testing. Patients can use the device at home rather than in a sleep laboratory.
"Giving patients in Ontario the ability to test for sleep apnea in the comfort of their own home represents a key validation for BresoTec as we look to bring our technology to international markets," says Dr. Geoff Fernie, CEO of BresoTec and Director, Research Institute, Toronto Rehab.
Through MaRS EXCITE, the Ontario-based company was able to collaborate with the Ontario Ministry of Health and Long-Term Care (MOHLTC) and other key stakeholders to gather the appropriate evidence and develop an implementation plan, key factors required for adoption within any health system.
#currentmood is a popular hashtag among social media users. It typically accompanies an amusing image depicting the user’s mood. But behind the tongue-in-cheek memes and grumpy cat pictures, there’s a huge amount of data that can provide insight into the human condition.
Previous studies have shown that those with mental health conditions use language differently than the general population. But that research has been limited to Twitter data, which is problematic for two reasons: first, tweets are short-form posts that may restrict users from discussing topics at length; and second, Twitter is not anonymous. This lack of anonymity is a drawback because previous research has found that anonymity is more likely to facilitate open and uninhibited discussions of mental health.
Dr. Frank Rudzicz (TRI Scientist) addressed these shortcomings by using data from Reddit, which is a long-form and anonymous social media forum. He focused specifically on how mood is affected by the season or length of day—with the aim of shedding light on those suffering Seasonal Affective Disorder, a subtype of major depression.
In the study, Dr. Rudzicz and his research student, Kawin Ethayarajh, examined comments from more than 100,000 Reddit users over the course of one year. They used Linguistic Inquiry and Word Count, a language analysis tool, to assign words into specific psychological categories such as anxiety, anger or sadness to determine mood.
After relating these data to the length of day on which the comments were posted (calculated based on the city of the user), they found that a subpopulation of users’ moods changed depending on the length of day.
“We are the first to demonstrate that Reddit comments can be used to study mood and mental health,” explains Dr. Rudzicz. “Our results provide a new direction for future research on the ways in which social media can be leveraged to benefit health care.”
This work was supported by the Toronto Rehab Foundation.
Have you ever had trouble remembering where you parked your car in a busy parking lot? The part of the brain that enables us to learn and remember this type of information is known as the hippocampus. The same region also processes emotion—not surprising given that memories often hold powerful emotional weight.
When something goes wrong in the hippocampus, we have trouble remembering. The challenge for researchers is figuring out exactly what went wrong. This is because the brain is a huge electrical network: specialized cells known as neurons communicate with each other by transmitting electrical signals. Proteins on the surface of neurons, known as ion channels, enable this transfer of information by controlling the flow of charged particles (ions) in and out of the cell.
One way to tackle this challenge is to develop and use computer models to simulate brain function—these models can be programmed to mimic the activity of individual cells or entire brain networks.
Krembil Senior Scientist Dr. Frances Skinner and her PhD student, Vladislav Sekulić, recently took this approach to figure out how ion channels in the hippocampus affects brain function.
Their models focused on the distribution of ion channels on a particular type of neuron called O-LM cells, which are important for gating information flow into the hippocampus. O-LM cells fire together (ie, in synchrony) with other cells in the hippocampus. When these cells fire 4-7 times per second, they are believed to contribute to processing emotions. In contrast, when they fire 7-12 times per second, they are believed to be helping to form a mental map of your surroundings.
By artificially adjusting the distribution of ion channels in their models, the researchers found that specific combinations and distributions of ion channels predispose, or “tune”, the cells to fire at either low or high firing rates. Thus, their models suggest that OL-M cells contribute to emotional or spatial learning in the hippocampus by virtue of having different and particular ion channel distributions.
“It is exciting to consider that our modeling approach has been able to make predictions about the roles of specific cell properties in memory processing,” says Dr. Skinner. “As O-LM cell activity can be measured using implanted electrodes, the next step will be to test our models’ predictions in freely behaving animals. By working together, computer modellers and experimentalists can develop an understanding of how memory systems work, and by extension, help discover new treatments for memory disorders.”
This work was supported by the Natural Sciences and Engineering Research Council of Canada, the SciNet HPC Consortium and the Toronto General & Western Hospital Foundation.
Sekulić V, Skinner F. Computational models of O-LM cells are recruited by low or high theta frequency inputs depending on h-channel distribution. Elife. 2017 Mar 20. Doi: 10.7554/eLife.22962.
Have you ever touched a hot surface? Almost instantly, your brain not only receives messages about heat and pain, but also sends a message to pull your hand away from the surface.
These messages are transmitted across a complex network of specialized cells, called neurons, in a matter of milliseconds. This rapid method of communication is accomplished using small chemical messengers termed neurotransmitters: the neuron sending the message releases neurotransmitters that are received by the next neuron, which continues to pass the message along in the same way.
Inside the sending neuron, neurotransmitters (ie, the message) are stored within “synaptic vesicles” (ie, the envelope). Synaptic vesicles fuse to the inner wall of the neuron nerve fiber terminal and rapidly release the neurotransmitters enclosed within, passing them on to the target neuron; however, it remains unclear how this function is accomplished.
It is for this reason that Krembil Senior Scientist Dr. Elise Stanley and her research team recently initiated a study to determine the exact interactions between synaptic vesicles and the sending neuron's inner wall. It is known that proteins embedded in the neuron’s wall, called voltage-gated calcium channels (CaVs), enable synaptic vesicles to fuse. Thus, the team used sophisticated techniques to label synaptic vesicles and CaVs; they then visualized these labelled structures with state-of-the-art electron microscopes. The team found that CaV proteins anchor synaptic vesicles in place, right next to the neuron’s inner wall. This CaV-synaptic vesicle binding could be the critical first step in triggering neurotransmitter release: the CaV may grab synaptic vesicles floating within the cell—bringing them close to the cell membrane such that they are ready to release their neurotransmitter contents.
“The results of this study contribute to our fundamental understanding of how cells in the nervous system communicate with one another,” says Dr. Stanley. “By building a more complete picture, we can identify molecules or processes that could be exploited for therapeutic purposes in cases where communication between neurons goes awry, as it does in degenerative or functional brain disorders such as Alzheimer disease or epilepsy.”
This work was supported by the Canadian Institutes of Health Research and the Toronto General & Western Hospital Foundation. E Stanley is a Tier 1 Canada Research Chair in Molecular Brain Science.
Chen RHC, Li Q, Snidal CA, Gardezi SR, Stanley EF. The calcium channel C-terminal and synaptic vesicle tethering: analysis by immuno-nanogold localization. Front Cell Neurosci. 2017 Mar 30. doi: 10.3389/fncel.2017.00085.
For mountaineers who push themselves too far, too fast, a particular type of chronic mountain sickness, known as high-altitude cerebral edema, can develop.
A recent study, led by Krembil Clinician Investigator Dr. Daniel Mandell, revealed an unlikely link between mountaineers suffering from this condition and patients in the intensive care unit (ICU).
Dr. Mandell comments, “Our study showed that critically ill patients displayed extremely small, yet extensive points of bleeding in the brain known as microbleeds—a phenomenon that is also experienced by those suffering from this type of altitude sickness.”
The impetus for the study was to help explore unexplained intellectual decline experienced by some ICU patients. While the ICU provides a vital lifeline to those recovering from conditions such as major surgery, serious infections or organ failure, these patients often experience lingering memory problems and trouble concentrating.
In the study, the research team used magnetic resonance imaging (MRI) to look at the brains of 12 ICU patients. Discussing the approach, Dr. Mandell comments, “We used a type of MRI called ‘susceptibility weighted imaging’, which provides exquisite detail of blood flow in the brain.”
The cause of the microbleeds observed in ICU patients is still unknown. “While microbleeds are known to result from prolonged exposure to high altitudes, chronic high blood pressure or diseases of the blood vessels, the majority of our study participants did not have any of these conditions. This suggests that the microbleeds that we observed are a new phenomenon—one that warrants further study,” says Dr. Mandell.
One potential explanation for the observed microbleeds could be that they are caused by low blood oxygen levels. This is a particularly attractive idea because, similar to mountaineers at high altitudes, low blood oxygen levels are experienced by ICU patients with respiratory failure. In fact, in the study, most of the 12 ICU patients exhibited respiratory failure and all but one of them required mechanical ventilation.
While it is still not clear whether microbleeds account for the unexplained intellectual symptoms experienced by ICU patients, these findings lay the groundwork for future studies that will explore this link and develop approaches to prevent microbleeds.
This work was supported by Remmert Adriaan Laan Fonds (Dr. Coutinho) and the Toronto General & Western Hospital Foundation.
Fanou EM, Coutinho JM, Shannon P, Kiehl TR, Levi MM, Wilcox ME, Aviv RI, Mandell DM. Critical Illness-Associated Cerebral Microbleeds. Stroke. 2017 Apr;48(4):1085-1087. doi: 10.1161/STROKEAHA.116.016289. Epub 2017 Feb 24.