Amyloid beta, the plaque that accumulates in the brains of people with Alzheimer’s disease, may also contribute to Alzheimer’s by interfering with normal blood flow in the brain, according to investigators at UAB.
In findings published in the journal Brain, the team shows that when amyloid beta accumulates around blood vessels — where it is known as vascular amyloid — it appears to prevent the brain from properly regulating blood flow, which is essential to normal brain function.
“We have increasingly become aware that the disruption of blood flow in the brain can increase the risk of Alzheimer’s disease,” said Erik Roberson, MD, PhD, associate professor in the UAB Department of Neurology. “While we have known that vascular amyloid built up around blood vessels, we did not fully understand its effects, and new technology now allows us to visualize how it affects the function of those vessels.”
Increased brain activity — remembering the lyrics to a song, for example — requires an increase in energy to the neurons responsible for memory. Neurons draw energy from glucose, which is transported by the blood stream. Cells called astrocytes regulate the diameter of blood vessels to increase or decrease blood flow and the corresponding glucose transportation. Astrocytes also tell the blood vessel to return to normal when the need has passed.
Astrocytes accomplish this signaling by means of projections called astrocytic endfeet, which wrap around the smooth muscle cells of the blood vessel wall. When a neuron calls for more glucose, the message is passed via the astrocytic endfeet, and the blood vessel expands and boosts blood volume.
The fate of astrocytic endfeet in a brain tumor study led the research team to look more closely at vascular amyloid. UAB researchers led by Harald Sontheimer, PhD, then a professor in the Department of Neurobiology, had published a paper in 2014 which showed that in brain tumors, malignant astrocytes called glioma cells could travel along blood vessels and push astrocytic endfeet away, severing their connection to the vessel and interfering with their ability to regulate blood flow.
“We know vascular amyloid accumulates around the outside of blood vessels, and after seeing those research findings from the Sontheimer group, we wondered if these plaques could be doing the same thing,” Roberson said. “Working with Dr. Sontheimer and his laboratory, we used advanced imaging techniques — including high-resolution, 3-D image reconstructions from multiphoton laser scanning microscopes, and sophisticated labeling and experimental techniques — and were able to determine that, yes, vascular amyloid did push the astrocytic endfeet away and interfered with normal regulation of blood vessels.”
“In a live animal model of Alzheimer’s disease, we then activated the vascular smooth muscle cells with a pulsed laser, allowing us to mimic neuron-induced astrocyte-vascular signaling,” said Ian Kimbrough, a graduate research assistant in Neurobiology. “In locations where no vascular amyloid was present, we saw a robust vessel response. However, on blood vessels that were surrounded by plaque, we saw a much diminished response.”
Kimbrough says that UAB is one of the few research centers in the Southeast with multiphoton laser-scanning microscopes, instruments capable of capturing images deep into a living brain. These images can then be used to create three-dimensional, volumetric representations of brain morphology.
“Using this 3-D model, which we can rotate and manipulate,” he said, “we can see the exact spatial relationship between the vasculature, the astrocytic endfeet and the vascular amyloid. This allows us to analyze how these elements interplay in a healthy brain compared to an Alzheimer’s disease brain.”
Roberson and Kimbrough say that, as the plaque buildup worsens, the vascular amyloid forms rings around the blood vessels, with bridges linking one ring to the next. These rings form a rigid exoskeleton on the vessels, restricting their ability to change in diameter when increased blood flow is demanded by neurons.
“The vessel has to be able to expand and contract, to dilate and constrict, if it’s going to regulate blood flow,” Roberson said. “If they have become rigid like a pipe, instead of having a flexible wall that can go back and forth, then they cannot do their job of regulating blood flow to the brain properly.
“This was among the first studies to attempt to understand the relationship between vascular amyloid and blood flow in the brain. For the first time, using our technology, we can see what is happening in the vessel walls in real time, to better understand how the presence of vascular amyloid effects the function of that vessel.”
Citizens Baptist Receives Chest Pain Center Accreditation
Citizens Baptist Medical Center has received full accreditation as a Chest Pain Center (CPC) from the Society of Cardiovascular Patient Care.
To receive the CPC accreditation, hospitals must meet an array of stringent criteria and undergo a comprehensive onsite review. Accredited hospitals possess expertise in dealing with patients who present with heart attack symptoms and emphasize the importance of standardized diagnostic and treatment programs. Additionally, accredited CPCs serve as a point of entry into the healthcare system to evaluate and treat other medical problems.
This recognition comes in part due to Citizens’ strong relationships with local EMS, a reduced time to treatment during the early stages of a heart attack, improved transfer and laboratory reporting times, and community education programs, along with enhanced onsite procedural systems.
CVA One of 36 Practices Nationwide to Receive Honor
Cardiovascular Associates has received the American College of Cardiology’s PINNACLE Registry Platinum Practice Center of Excellence Award. CVA is one of only 36 practices nationwide to receive the honor.
The award recognizes CVA’s success in implementing a higher standard of care for patients with atrial fibrillation who are at an increased risk of stroke. Atrial fibrillation, the most common arrhythmia, is responsible for 15 to 20 percent of all strokes.
To receive the PINNACLE Registry’s Platinum Practice Center of Excellence award, CVA demonstrated a platinum benchmark on the nationally recognized atrial fibrillation metric. Full participation in the registry engages practices in a robust quality improvement process using data to drive improvements in adherence.
BlueCross and BlueShield Adds Telemedicine Services
BlueCross and BlueShield of Alabama has started a statewide initiative to pay providers for telemedicine services. Due to a lack of subspecialist physicians in certain rural communities, there are often gaps in specialty medical care when compared to larger cities.
This initiative is designed to help fill those gaps for Alabamians and provide care for conditions in the following categories:
- Cardiac conditions
- Behavioral health
- Dermatologic conditions
- Infectious disease
- Neurologic diseases
“We are proud to support telemedicine because we want our members to have access to quality healthcare wherever they are in Alabama. With the innovative technology available today, we are now able to do that,” said Doug McIntyre, Vice President of Network Operations of BlueCross and BlueShield of Alabama.
Telemedicine successfully exchanges medical information about a patient from one originating site to another distant site via two-way telecommunications systems that are real-time, interactive, secure and HIPAA compliant.
This is just one part of BlueCross and BlueShield of Alabama’s statewide initiative, “Circle of Care” Primary Care Select Program, a long-term investment to help improve access to healthcare in Alabama.
St. Vincent’s Expands One Nineteen Campus
St. Vincent’s Health System recently held a ribbon cutting for the expansion of its One Nineteen Campus, which will include outpatient surgery, urgent care and additional physician offices.
“More than 10 years ago, St. Vincent’s set out to create a new kind of healthcare in the community. Healthcare focused on taking care of you when you’re sick, but also providing health and wellness support to keep you well. That model was One Nineteen,” said Neeysa Biddle, Senior Vice President, Ascension Health.
The Outpatient Surgery Center offers same-day surgical procedures with four operating rooms and two procedure rooms.
Urgent Care on the One Nineteen campus offers: walk-in care for minor injuries; weekday and weekend hours with no appointment needed; lower overall cost than an emergency room visit; coordination with primary care physician; accessible parking; and advanced technology, including digital X-ray and electronic medical records system.
In addition to the expansion pieces, St. Vincent’s One Nineteen has more than 50 physicians in 14 medical specialties, a comprehensive outpatient diagnostic imaging center, rehabilitation services, GI Lab, a spa and fitness center.
