“Clinicians and researchers need to work together to better understand the interactions between stroke, vascular disease, and Alzheimer’s disease in order to tackle neurodegeneration. You can’t focus on one disease and think that you’re going to fix the whole problem.” Dr. Sandra Black
Neurodegeneration is a kind of battle between two processes: one that slowly destroys brain cells and another that tries to repair the damage and keep going. According to Dr. Sandra Black, “under attack are not only nerve cells but also glial and vascular endothelium, a close family of cells called the ‘neurovascular unit.’ Eventually, the capacity to fight back and repair becomes overwhelmed and the family network of near and distant relatives, finally succumbs.”
The silver lining is that the brain can adapt to injury and keep functioning long into this battle, and we all have some capacity to build up our brain’s resilience to network disruption.
The preventative measures each of us can take to build cognitive resilience is a topic that is being explored within several CCNA teams, including Sylvie Belleville’s work on how to build resilience through engaging in meaningful activities, and Melissa Andrew’s research on how progression of disease relates to a multitude of factors, including one’s social environment. Black’s research focuses on the added (and possibly interactive) effects of multiple diseases playing out in the aging brain.
These commonly include Alzheimer’s and Cerebral Small Vessel Disease, as well as combinations of misfolded proteins involved in other neurodegenerative disorders, such as Parkinson’s and Lewy Body Disease. What threads such distinct diseases as Alzheimer’s and stroke together is that each causes damage to blood vessels – i.e. they are “vasculopathies”. The complexities of these conditions also call for the development of combination therapies, or “cocktail approaches” to address the many targets involved, Black explains.
Understanding more about where these diseases intersect requires researchers to carefully characterize the clinical profile, identify gene patterns, and quantify what is seen in brain scans, blood and spinal fluid samples, in parallel with experimental studies to discover effective treatments.
To that end, many of Black’s contributions stem from the longitudinal Sunnybrook Dementia Study, a multidisciplinary research project that began in the mid-1990s and is still underway. This study involves standardized imaging and neurobehavioural assessments on “real world” patients from Sunnybrook’s memory clinic. After having studied approximately 1300 patients over the years, who met basic eligibility criteria (i.e. no serious illnesses and well enough to do the tests), it became apparent that many individuals had small vessel disease, which shows up on brain MRI scans as white spots, patches, and black dots.
“About 95% of people over 65 have some degree of this small vessel disease, making it a very prevalent finding in human aging, and 20% of people over 65 have extensive patches in the white matter around the brain’s ventricles.”
Following almost 200 patients to autopsy, Black and her colleagues Drs. Keith and Gao have concluded that these white patches represent excess fluid around veins deep in the brain, whose walls thicken with age and high blood pressure; which makes it challenging for veins to adequately circulate blood and also for toxins, such as amyloid, to be cleared from the brain.
Since 2013, Black and Dr. Mario Masellis, an expert in genetics, Parkinson’s and Frontal Dementia syndromes, have been co-leading CCNA’s Theme 2 (Treatment) and support the seven teams within it. Dr. Black also oversees a core lab for a number of brain imaging projects. Her group provides structural imaging analysis lab and quality control for the MRI platform of the Ontario Neurodegenerative Diseases Research Initiative. She shares core brain imaging lab services (e.g. quality control, incidental findings and volumetric analysis) with Dr. Eric Smith at University of Calgary, for the CIHR-funded Tomorrow project, the Canadian Alliance for Healthy Hearts and Minds.
For her many contributions to the field of dementia, it is no wonder that Dr. Sandra Black was recently appointed as an Officer of the Order of Canada. Equally remarkable is the fact that her mother, Harriet Black, was also named to the Order over 30 years ago for her outstanding volunteerism to improve education, community health and social welfare, and to develop the arts in Sault St. Marie, where Black grew up. Her mother experienced dementia in her last years and recently died from a stroke in her 98th year. She was buried last summer in the Sault amidst family and friends on the day of the Order of Canada’s announcement.
In Black’s words, “I am deeply honoured and humbled by this wonderful recognition– it feels as if my mother has passed on the torch, and her service to community and country is a hard act to follow!”