Dr. Karmin O
Integrative Biology Laboratory, Canadian Centre for Agri-Food Research in Health and Medicine
Animal Science, University of Manitoba
Understanding mechanisms of vascular disorders: beneficial effects of nutraceutical and herbal medicines
Cardiovascular disorders due to atherosclerosis are the leading cause of death in North America. Atherosclerosis is characterized by thickening, hardening and loss of elasticity of the arterial wall, which can lead to fatal blockage of arteries. Kidney ischemia/ reperfusion injury is a major cause of kidney failure in patients with kidney disorders or receiving kidney transplantation. One of the common features in atherosclerosis and ischemia/reperfusion injury is oxidative stress followed by a multitude of intracellular signaling events that ultimately lead to the dysfunction/death of cells. Effective interventions at these early cellular events represent a novel approach to therapeutics.
Hyperhomocysteinemia – A new risk factor for cardiovascular disease
It is now recognized that the elevation of an intermediate amino acid known as homocysteine, formed during the conversation of methionine to cysteine, is a common and independent risk factor for cardiovascular disorders resulting from atherosclerosis. Elevated homocysteine levels in the blood, known as hyperhomocysteinemia, may represent an important and potentially modifiable risk factor for cardiovascular disease. Dr. O’s laboratory has been actively investigating the biochemical and molecular mechanisms of homocysteine-induced adverse effect in the blood vessel wall. Her research team has found that homocysteine can cause tissue damage through its ability to stimulate inflammatory responses in vascular cells leading to increased gene expression of inflammatory molecules such as free radicals, chemokines and adhesion molecules via oxidative stress. These molecules, in turn, contribute to the accumulation of lipids and blood cells in the vessel wall causing plaque formation in arteries and tissue injury.
Beneficial effect of folic acid supplementation
Folic acid (folate) supplementation, either alone or in combination with other vitamin Bs, has received attention as a promising approach in the prevention and treatment of cardiovascular diseases associated with hyperhomocysteinemia as well as with other risk factors. The beneficial effect of folate is partially attributed to its ability to lower blood homocysteine levels. Folate may also exert a protective effect against cardiovascular diseases associated with other risk factors. However, the mechanism of folate action other than its ability to reduce homocysteine, are largely unknown. It is not clear whether folic acid supplementation can improve endothelial function in individuals who have already developed hyperhomocysteinemia or other types of vascular disorders. Dr. O’s laboratory is investigating the molecular mechanisms of risk factor-induced atherosclerosis and the protective effect of folic acid (folate) supplementation on the hyperhomocysteinemia-induced oxidative stress and inflammatory response in vascular cells.
Validating health claims with scientific data
The goal of Dr.O’s research program is to develop scientific tests for the health claims for nutraceuticals and herbal medicine. Currently, Dr. O’s laboratory is actively exploring the underlying mechanisms for the beneficial effects of compounds or extracts such as folic acid, Reishi mushrooms (also known as Ganoderma lucidum or Lingzhi), polyunsaturated fatty acids (omega-3 fatty acids), Ginkgo biloba leaf extract (EGb) and various flavonoids in vascular disorders. Understanding the mechanisms of nutraceutical actions may also lead to the discovery of a novel therapeutic approach that can reduce adverse side effects of current treatment. Such research will certainly strengthen the scientific and technological base of nutraceuticals and herbal medicine, which will help enhance public confidence in this preventive approach to medical care.
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Dr. Karmin O