Posts tagged vascular diseases

Future prevention and treatment strategies for vascular diseases may lie in the evaluation of early brain imaging tests long before heart attacks or strokes occur, according to a systematic review conducted by a team of cardiologists, neuroscientists, and psychiatrists from Icahn School of Medicine at Mount Sinai and published in the October issue of JACC Cardiovascular Imaging.

For the review, Mount Sinai researchers examined all relevant brain imaging studies conducted over the last 33 years. They looked at studies that used every available brain imaging modality in patients with vascular disease risk factors but no symptoms that would lead to a diagnosis of diseased blood vessels (vascular disease) in the  heart or brain, or periphery (e.g. arms and legs).

The review demonstrates that patients with high blood pressure, diabetes, obesity, high cholesterol, smoking, or metabolic syndrome, but no symptoms, still had visible signs on their neuroimaging scans of structural and functional brain changes long before the development of any events related to vascular diseases of the heart (heart attack) or brain (stroke).

"This is the first time we have been able to disentangle the brain effects of vascular disease risk factors from the brain effects of cardiovascular and cerebrovascular disease and/or events after they develop," says the article’s lead author, Joseph I. Friedman, MD, Associate Professor in the Departments of Psychiatry and Neuroscience at Icahn School of Medicine at Mount Sinai. "Moreover, subtle cognitive impairment is an important clinical manifestation of these vascular disease risk factor-related brain imaging changes in these otherwise healthy persons."

Dr. Friedman added that, because diminished cognitive capacity adversely impacts a person’s ability to benefit from treatment for these medical conditions, early identification of these brain changes may “present a new window of opportunity” for doctors to intervene early and improve prevention of advancement from vascular disease risk factors to established cardiovascular and cerebrovascular diseases. His team is currently testing these hypotheses in ongoing studies at Mount Sinai.

"Patients need to start today to control their vascular risk factors, otherwise their brains may forever harbor physical changes leading to devastating heart and vascular conditions impacting their future overall health and even cognitive decline causing diseases like dementia or when it exists it can accelerate Alzheimer’s," says study author, Valentin Fuster, MD, PhD, Director of Mount Sinai Heart, Physician-in-Chief of The Mount Sinai Hospital, and Chief of the Division of Cardiology at Icahn School of Medicine at Mount Sinai. "Our publication raises the possibility that these early brain changes are major warning signs of what the future may hold for these asymptomatic patients. These high risk patients, along with their doctors, hold the power to modify their daily vascular risk factors to help halt the future course of the manifestation of their potentially looming cardiovascular diseases."

"We hope our publication serves as a primer for cardiologists and other doctors interpreting the early neuroimaging data of their patients who may be high risk for vascular disease," says senior article author Jagat Narula, MD, PhD, Director of Cardiovascular Imaging, Professor of Medicine and Philip J. and Harriet L. Goodhart Chair in Cardiology at Icahn School of Medicine at Mount Sinai. "These subtle brain changes are clues to us physicians that our patients need to start to lower their vascular risk factors always and way before symptoms or a cardiac or brain event happens. This simple step to lower vascular risk factors can have huge impacts on global prevention efforts of cardiovascular diseases."  

Researchers identified the following impact of key vascular risk factors on the structural and functional brain health of asymptomatic patients:

• Hypertension is associated with globally appreciable brain volume reductions,
  connecting brain fiber abnormalities, reduced brain blood flow, and alterations in the normal pattern of synchronized brain activity between different regions.
• Diabetes is associated with connecting brain fiber abnormalities, reduced brain blood flow, and alterations in the normal pattern of synchronized brain activity between different regions.
• Obesity is associated with brain volume reductions, reduced brain blood flow and metabolism.
• High total cholesterol and LDL cholesterol are associated with brain volume reductions, and connecting brain fiber abnormalities. In addition, high triglycerides is associated with reduced brain blood flow, and high total cholesterol is associated with reduced brain metabolism.
• Smoking is associated with brain volume reductions, and alterations of the normal pattern of blood flow. In addition, it causes reduced MAO B (Monoamine Oxidase B) which metabolizes dopamine, the neurotransmitter chemical that controls the brain’s reward and pleasure zones.
• Metabolic Syndrome is associated with a greater burden of silent brain infarcts (SBIs), visible only on MRI, which represents subclinical cerebrovascular disease. In addition, it is associated with connecting brain fiber abnormalities, and alterations in the normal pattern of synchronized brain activity between different regions.

(Source: mountsinai.org)

Over the last 15 years, researchers have found a significant association between vascular diseases such as hypertension, atherosclerosis, diabetes type 2, hyperlipidemia, and heart disease and an increased risk of Alzheimer’s disease. In a special issue of the Journal of Alzheimer’s Disease, leading experts provide a comprehensive overview of the pathological, biochemical, and physiological processes that contribute to Alzheimer’s disease risk and ways that may delay or reverse these age-related abnormalities.

“Vascular risk factors to Alzheimer’s disease offer the possibility of markedly reducing incident dementia by early identification and appropriate medical management of these likely precursors of cognitive deterioration and dementia,” says Guest Editor Jack C. de la Torre, MD, PhD, of the University of Texas, Austin. “Improved understanding coupled with preventive strategies could be a monumental step forward in reducing worldwide prevalence of Alzheimer’s disease, which is doubling every 20 years.”

The issue explores how vascular disease can affect cerebral blood flow and impair signaling, contributing to Alzheimer’s disease (AD). The diagnostics of cardiovascular risk factors in AD are addressed, as are potential therapeutic approaches.

Paradoxically, the presence of vascular risk factors in middle age is associated with the development of AD more strongly than late-life vascular disease. In fact, some research suggests that vascular symptoms later in life may have a protective effect against the development of the disease. The physiopathological mechanisms that may underlie this phenomenon are discussed.

To date, trials that target major cardiovascular risk factors in the prevention of AD remain inconclusive but have become an important focus of international research as described by contributors of this special volume in their overviews. The multifactorial nature of AD and the need to identify the proper time window for intervention when designing possible interventions, and methodological issues that will have to be addressed to achieve an optimal design of new randomized controlled trials, are discussed. Promising avenues for treatment, such as the potential of low-level light therapy to increase the rate of oxygen consumption in the brain and enhance cortical metabolic capacity, and the possibility that some antihypertensive drug classes reduce the risk and progression of AD more than others, are discussed.

Dr. de la Torre notes that the presence of vascular risk factors is not an absolute pathway to dementia, and it may be as important to study how or why individuals who are cognitively normal but have vascular risk are able to avoid dementia. “Reducing Alzheimer’s disease prevalence by focusing right now on vascular risk factors to Alzheimer’s disease, even with our limited technology, is not a simple or easy task. But the task must begin somewhere and without delay because time is running out for millions of people whose destiny with dementia may start sooner rather than later,” he concludes.

(Source: alphagalileo.org)