Dr. Chris Siow
– Innovative Therapy Research Laboratory

Dr. Chris Siow
Principal Investigator
Innovative Therapy Research Laboratory

Research Focus

We believe the gateway to cardiovascular health is through the action of herbal compounds on components of the human kinome.

The kinome is a subset of the genome consisting of protein kinase genes.

Our research interest is to understand the biochemical and molecular mechanisms of herbal medicines that are used in health promotion and disease therapy. Our aims are to study the beneficial health effects of selected natural health products (incl. herbal medicine) and to examine their underlying mechanisms with the goal to develop innovative strategies for health maintenance and disease management. We also aim to establish analytical protocols for the identification of bioactive compounds derived from natural products and delineating the molecular mechanisms by which these compounds affect expression and function of the components in cellular signalling cascades.

Why is this work important?

The population of Canada and the rest of the world are aging. With aging, an increasing incidence of chronic diseases will be expected. While some of these diseases are genetically-linked, many are lifestyle and diet-related. These latter ones are preventable to a certain extent. Besides changing their lifestyle and eating healthier food, consumers have also resorted to self-administration of natural health products (NHP). In a recent survey (View PDF) of Canadians by Ipsos-Reid for the Natural Health Products Directorate of Canada, 71% of Canadians have used an NHP. The survey has also found that 77% of Canadians are supportive of health claims on NHPs as long as they are backed by scientific evidence. Included in the definitions of NHPs are herbal remedies, homeopathic medicines, and traditional medicines such as Traditional Chinese Medicines (TCM). Our laboratory aims to provide the science behind the claims of these NHPs so that Canadians can make informed choices.

What techniques and equipment are used in this laboratory?

Using a recently acquired new technology in separation science termed ultra-performance liquid chromatography (UPLC) and the available chemistries, we continue to develop protocols to identify bioactive compounds found in various agricultural and medicinal herb extracts. The UPLC system provides significant improvements in resolution, speed and sensitivity when compared to traditional high performance liquid chromatography.

Our laboratory is also capable of routinely measuring the antioxidant capacity of a compound or an extract, using a microplate-based assay system. Two parameters will be measured: total phenolics and oxygen radical absorbance capacity (ORAC), using gallic acid and trolox as controls, respectively.

Identified bioactive compounds and standardized agricultural and medicinal herb extracts will be used to study its protective effects on ischemia/reperfusion using a few different model systems.

About Chris Siow

Dr. Siow earned a PhD in Biochemistry from University of Manitoba. He did his first post-doctoral research training with Nobel laureate Paul Greengard at The Rockefeller University in New York and then a second post-doctoral training at University of British Columbia. Dr. Siow began his independent research in the Department of Pharmacology,The University of Hong Kong and returned to Canada in 2003. He was appointed an Assistant Professor in the Department of Physiology, University of Manitoba. Dr. Siow’s research is funded by many public and private agencies. He has extensive experience working with industry and has led a university-industry collaborative government-funded multimillion-dollar project to assist the industry partner to modernize and provide a scientific basis for one of their herbal medicine based therapeutic products. He has published over 50 papers in international peer-reviewed scientific journals and is serving as an Associate Editor of the Canadian Journal of Physiology and Pharmacology. He is a Founding Board Member and currently a Regional Director of the Canadian Institute of Chinese Medicinal Research.

For more information, please contact:

Dr. Chris Siow
Tel. 204.235.3457
Email. csiow@sbrc.ca

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In Detail

Dramatic progress has been made in unravelling the multitude of signal transduction pathways in the cell. Abnormalities in these signalling pathways are demonstrated in many diseases. These include proliferative diseases like atherosclerosis, cancer, psoriasis and restenosis, inflammatory diseases such as rheumatoid arthritis, sepsis and tissue rejection, and degenerative diseases such as Alzheimer’s disease and amyotrophic lateral sclerosis (Lou Gehrig’s Disease). Drugs that intervene at these signalling processes represent a novel type of therapy for cardiovascular diseases. The goal of our research is to develop innovative therapeutic approaches based on agricultural and herbal medicine that target cell signaling processes. We will use innovative strategies to identify the mechanisms and accelerate the subsequent development of standardized natural health product and therapeutic formulations based on agricultural and medicinal herbs.

Study Models

Ischemia/reperfusion is a cellular process that can lead to cellular damage/death. Ischemia occurs when there is a blockage of blood vessels supplying oxygen and nutrients to particular region of an organ or parts of a tissue. If it occurs in the heart, it is known as myocardial infarct or heart attack. Reperfusion is established when there is restoration of blood flow through the blood vessels, upon successful surgical or drug intervention to remove the blockage. The ischemia/reperfusion process also causes cells to undergo stress and produce to undergo stress and generate oxygen free radicals and other cellular metabolites. All of these can cause an extremely rapid increase in cell death by a programmed and active mechanism of cell death known as apoptosis. Intervention by pharmacological means can prevent cellular damage/death.

Our present model for study is simulated ischemia/reperfusion in a cell culture model. The endpoint of the model system is apoptotic cell death following simulated ischemia/reperfusion. Apoptosis is determined by measurement of nucleosomal formation by quantitative in vitro determination of cytoplasmic histone-associated-DNA-fragments. The nucleosomal formation during the reperfusion period will also be assessed. Apoptosis will also be confirmed by simultaneous TUNEL-based apoptosis detection and morphological localization under a light microscope and by performing Western blots using antibodies specific for poly(ADP-ribose) polymerase (PARP).

Another model system for study is the Langendorff isolated rat heart model system to study the effects of global ischemia/reperfusion. With this model system, assessment of heart function via ECG assessment by other CCARM members can be performed. In this way, we can evaluate the pharmacological value of the bioactive ingredient of interest.

Analytical

Through CFI and MRIF, my laboratory has acquired a new technology in separation science termed ultra-performance liquid chromatography (UPLC). The UPLC system provides significant improvements in resolution, speed and sensitivity when compared to traditional high performance liquid chromatography in the identification of bioactive compounds. Our UPLC system is coupled to a photodiode array (PDAD) detector and an evaporative light scattering detector (ELSD). The dual detector coupled to the system can provide a profile of sample components which are both chromophoric (UV) and non-chromophoric (ELSD). The addition of the ELSD allows detection of samples which are unaffected by changes in the spectroscopic properties and compositional changes in the mobile phase. Using the UPLC system, we can obtain a chromatographic profile of a natural product extract. The chromatographic profile of a raw natural product extract that insures the extract’s bioactive components are consistent from batch to batch. This profile (fingerprint) usually varies between plant species, although the intensities of the various peaks may vary depending on growing conditions, harvesting climate, region of cultivation, etc. This chromatographic profiling is a reliable approach for controlling quality. Our present system has been optimized to separate several major anti-oxidants (this class of compounds is what intrigues us now).

The phenolic content of a food product is known to account for its anti-oxidant activity. This activity is mainly due to the redox properties of phenolics which allow them to act as reducing agents, hydrogen donors, singlet oxygen quenchers and metal chelators. Total phenolics are determined using the Folin-Ciocalteau phenol reagent and has been adapted in our laboratory for use in a 96-well microplate format. Using gallic acid as a standard, results are expressed as mg Gallic Acid Equivalents (GAE).

The oxygen radical absorbance capacity (ORAC) measurement is also a widely used assay to measure antioxidant activity. It provides a measure of the degree and length of time it takes to inhibit the action of oxygen free radicals or reactive oxygen species. Therefore, the higher the ORAC value, the better the antioxidant capacity of the substance. These substances include natural products such as fruits, vegetables, and herbal medicines, beverages, dietary supplements, serum or other biological fluids. In our laboratory, we are using a microplate-based system for measuring the ORAC value of an extract. This value is determined based on the oxidation of fluorescein by 2,2–azobis amidino(propane) dihydrochloride, a peroxyl radical generator. The downward change in fluorescent intensity is followed kinetically and ORAC values are calculated from the decay in fluorescence. The presence of antioxidants will delay the oxidation of fluorescein, resulting in preservation of the fluorescent signal. Using Trolox as a standard, the results are expressed as mol Trolox equivalents.

2010

The research program in my laboratory (R2010) focuses on cardiovascular health benefits. Through interdisciplinary collaborations within CCARM and other research groups, isolated compounds will be screened in other organ systems or diseases for beneficial bioactivities. We presently have several international collaborations and are working with local industries to explore the health benefits of regionally grown natural products. Therefore, the road to 2010 will not only lead to the Vancouver Winter Olympics but will also lead to new and innovative therapy for many diseases.

“More and more of our patients want us … to help them follow a path to health that includes less-toxic nutrients and herbs when appropriate, combining the best scientific knowledge with an open mind” Jane L. Murray, M.D., Editorial, American Family Physician, Feb 1, Vol. 73, pp396-8, 2006

Top

1. Au-Yeung KKW, O K, Choy PC, Zhu DY, and Siow YL (2007) Magnesium tanshinoate B protects endothelial cells against oxidized lipoproteins-induced apoptosis. Can.J.Physiol. Pharmacol. 85: In Press

2. Fan J, Li X, Li P, Li M, Wang T, Shen H, Siow YL, Choy PC, and Gong Y (2007) Saikosaponin-d attenuated the development of liver fibrosis through prevention of hepatocyte injury. Biochem Cell Biol. 85(2): 187-193.

3. Siow YL, Au-Yeung KKW, Woo CWH, and O K (2006) Homocysteine stimulates phosphorylation of NADPH oxidase p47phox and p67phox subunits in monocytes via protein kinase C-beta activation. Biochem.J. 398(1): 73-82.

4. Siow YL, Gong Y, Au-Yeung KKW, Woo CWH, Choy PC, and O K (2005) Emerging issues in traditional Chinese medicine. Can. J. Physiol. Pharmacol. 83, 321-334

5. Zhang H, Yu C, Jia JY, Leung SWS, Siow YL, Man RYK and Zhu DY (2002) Study on the contents of four active components in different commercial crude drugs and preparations of Danshen (Salvia miltiorrhiza). Acta Pharmacol. Sinica. 23(12): 1163-1168.

6. O K, Lynn EG, Vazhappilly R, Au-Yeung KKW, Zhu DY, and Siow YL (2001) Magnesium tanshinoate B (MTB) inhibits low density lipoprotein oxidation. Life Sci. 68(8): 903-912.

7. Au-Yeung KKW, Zhu DY, O K, and Siow YL (2001) Inhibition of stress-activated protein kinase in the ischemic/reperfused heart: Role of magnesium tanshinoate B in preventing apoptosis. Biochem. Pharmacol. 62: 483-493.

Outstanding Researcher Award, University of Hong Kong

University of Hong Kong Research Fellow Award

Canadian Foundation for Innovation

Manitoba Research Innovation Fund

Heart & Stroke Foundation of Manitoba

Lotte and John Hecht Memorial Foundation

Natural Health Products Directorate (Health Canada)

Manitoba Medical Services Foundation

The Estate of Marguerite Germaine Jerome

There are no opportunities available at this time.