Review Article. The Anti-Diabetic Effects of Hydroxytyrosol from Olea Europaea

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1 The Anti-Diabetic Effects of Hydroxytyrosol from Olea Europaea Nancy B. Ray, PhD; Tom Karagiannis, PhD; D. Elizabeth McCord, PhD, FAPWCA T he number of people with Type-2 Diabetes is reaching epidemic proportions. According to the International Diabetes Federation (IDF) report in 23, there are 283 million people living with diabetes worldwide. Changing lifestyles, rapid urbanization, and cheap calories from processed foods are putting increasing numbers of people at risk for developing Type-2 diabetes. The economic burden from Type-2 Diabetes has probably been underestimated, which has delayed prevention and management strategies (K-H Yoon et al, 2). Diabetes mellitus is a group of metabolic disorders resulting from hyperglycemia and excess inflammation that is caused by defects in either insulin secretion and/or action. The most common form, Type-2, is a result of insulin resistance in peripheral tissues. If left untreated, diabetes can result in serious long-term complications including cardiovascular diseases, nephropathy, retinopathy, neuropathy, and chronic wounds including diabetic foot ulcers (Karagiannis 2). Diabetic foot ulcers are estimated to occur in 5% of all patients with diabetes, and are the cause of 8% of all diabetes-related lower leg amputations. They are a leading cause of morbidity, which is often preceded by pain, suffering, and a poor quality of life for those patients (Bem and Tomic-Canic 27). Normal wound healing is vital for replacement and repair of tissue and for the restoration of tissue to its functional state. Diabetic foot ulcers and other chronic wounds do not follow the orderly process of normal wound healing that requires a well-orchestrated integration of complex biological events including cell migration, cell proliferation, and extracellular matrix deposition. The normal repair process is divided into four overlapping phases of coagulation, inflammation, migration-proliferation (including matrix deposition), and remodeling. This complex process involves the interplay of different cell types including keratinocytes, fibroblasts, and endothelial cells. The intrinsic abnormalities associated with diabetes including hypoglycemia, circulatory/vascular deficiencies, and

2 Page 2 neuropathy all contribute to an abnormal progression of wound repair as well an abnormal wound environment (Falanga 25). Oxidative stress induced by hyperglycemia plays an important role in endothelial cell dysfunction and wound healing impairment. During normal healing, microvascular endothelial cells migrate to form new blood vessels (angiogenesis) in response to wounds (Hadi and Suwaidi 27). However, the metabolic abnormalities of diabetes cause mitochondrial superoxide overproduction in both large and small bloodvessels, leading to the dysfunction of vascular cells. It was shown that increased expression of MnSOD in endothelial progenitor cells improved their angiogenic functions (Marotte et al, 2). Research performed by Dr. Ehab Sarsour and funded by McCord Research at the University of Iowa, has previously shown that the antioxidants, hydroxytyrosol and N-acetyl-L-cysteine, found in the (also known as the ), induced substantial increases in MnSOD expression and activity. Therefore, it was hypothesized that the McCord Formula might decrease endothelial dysfunction and improve wound healing. The improves cell migrationin an in vitro model of wound healing in human microvascular endothelial cells. Time (following scratch (hours) Time for 5% of the wound to heal (hours) 8 2. ± ±. Figure : The accelerates cell migration and improves wound healing in human microvascular endothelial cells (HMEC-). Cells were pretreated with the for 2 hours, then scratched and imaged regularly until complete wound closure. The time taken for 5% wound closure was recorded.

3 Page 3 Research to investigate this hypothesis was performed in the McCord Laboratory directed by Dr. Thomas Karagiannis, located at the internationally renowned Baker IDI Heart and Diabetes Institute in Melbourne, Australia. Dr. Karagiannis is a leader in the field of diabetes, and he has published many excellent peer-reviewed papers in this area. In initial experiments, human microvascular endothelial cells (HMEC) were first exposed to a normal glucose environment and wound healing was examined. It was discovered that the accelerated HMEC migration (an indicator of normal endothelial function) by 5% suggesting that the antioxidant properties of the ingredients found in promote wound healing. The time required for 5% wound closure was then Treatment Hydroxytyrosol Oleuropein N-acetylcysteine Proline Glycine Taurine without Hydroxytyrosol Oleuropein N-acetylcysteine Proline Glycine Taurine determined using individual components of the compared to the complete, and compared to the McCord Formula with specific components removed. The resulted in the shortest time required for wound healing followed by hydroxytyrosol, which when removed from the Formula also resulted in the greatest time required for wound healing. Next, wound closure was tested using a model of glucose-impaired wound healing that simulates endothelial dysfunction and impaired wound healing that occurs in individuals with diabetes. For comparison, impaired wound healing was also induced by the chemotherapeutic agent, doxorubicin. Time for 5% of the wound to heal (hours) SD Table : required for 5% wound closure following treatment with, individual components, and without speciiic components. The synergistic effect of all the components in the formulation resulted in shortest wound closure time (best wound healing effect). Removal of hydroxytyrosol from the resulted in the longest wound closure time and therefore greatest decrease in effectiveness of the.

4 Page Time (following scratch (hours) µm doxorubicin + µm doxorubicin Glucose and doxorubicin impairs cell migrationin an in vitro model of wound healing in human microvascular endothelial cells. µm doxorubicin + µm doxorubicin Time for 5% of the wound to heal (hours) 2. ±.77.2 ± ± 3.3 3mM glucose + 3mM glucose µm doxorubicin + µm doxorubicin Time (following scratch (hours) 3mM glucose + 3mM glucose U 3 M Time for 5% of the wound to heal (hours) 3mM glucose + 3mM glucose 2. ± ± ± 5.3 Figure 2: The restores microvascular endothelial (HMEC) cell migration and wound closure in the Doxorubicin and high glucose model of impaired wound healing.

5 Page 5 It was discovered that the () accelerated endothelial cell migration during glucose or doxorubicin-impaired wound healing, suggesting that the can decrease endothelial cell dysfunction and restore normal rates of wound healing. It is well known that umbilical cells are very adaptable and have amazing potential. It has also been shown that transplanting normal human umbilical endothelial cells into diabetic wounds can decrease diabetic wound healing times (Kim, 2). also decreased wound healing times in this model. has a significant effect on umbilical cell migration, as indicated in normal cells and by a % improvement of cell migration following treatment with high glucose. also decreased wound healing times in this model. A vascular tube formation assay was also performed with human umbilical vein endothelial cells (HUVEC) to further explore the effects of on angiogenesis and wound healing. It was discovered that improved vascular tube formation (angiogenesis) in these cells suggesting again that improves wound healing. improves cell migration by % in human umbilical vein endothelial cells, following treatment with high glucose (Pre-treatment for 72 hours with 3mM glucose) CONTROL Time following scratch (hours) 2 HIGH GLUCOSE Time following scratch (hours) 2 Hydroxytyrosol Hydroxytyrosol 9.7 ± ± 3.2 Hydoxytyrosol 2.9 ± Hydoxytyrosol Figure 3: improved cell migration and wound healing in human umbilical vein endothelial cells (HUVEC) pre-treated with high glucose (3 mm) for 72 hours. Hydroxytyrosol also improved wound healing compared to untreated cells.

6 Page Figure : improves angiogenesis (vascular tube formation) in human umbilical vein endothelial cells (HUVEC). Mean ± standard deviations from a single experiment performed in triplicate are shown; total of 2 independent experiments tested. Hyperglycemia that occurs during diabetes may cause a shift toward a more oxidizing environment in the process of wound healing. It has also been proposed that increased glucose metabolism during cellular proliferation may accompany a shift in the cellular redox environ-ment towards a more oxidizing environment (Sarsour, Cancer Research 22). Relative Antioxidant Activity (%) Total Tube Length in µm (x3) 2. PBMC 2%.5..5 Oleuropein Hydroxytyrosol Hydroxytyrosol also substantially increased the antioxidant capacity of PBMC. Changes in the expression of genes involved in the antioxidant defense system were also examined following treatment of keratinocytes and K52 leukemic cells with different concentrations of hydroxytyrosol. Upregulation of several enzymes involved in the defense system was found (Rafehi et al, 22) including marked upregulation of an enzyme with potent anti-inflammatory properties (Paine2), heme oxygenase- (HO-)..5 Relative Antioxidant Activity As mentioned previously, oxidative stress by hyperglycemia plays an important role in wound healing impairment. To test the antioxidant activity of, antioxidant capacity was measured in normal peripheral blood mono-nuclear cells (PBMC) as well as in PBMC exposed to high glucose and doxorubicin. 75% 57% PBMC High Doxorubicin Glucose High Doxorubicin + Glucose + Figure 5: improves the antioxidant capacity of normal PBMC. also restored the depleted antioxidant capacity induced by stress with high glucose by 7% and doxorubicin by 82%. Mean ± standard deviations from an experiment performed in triplicate are shown; 2 independent experiments were performed.

7 Page 7 Recent evidence suggests that the mitochondrial antioxidant defense enzyme, manganese superoxide dismutase (MnSOD), and mitochon-drial generated reactive oxygen species (ROS) regulate a metabolic shift in the transition of cells from non-dividing (quiescent) to proliferating. Dr. Ehab Sarsour (with funding from McCord Research) at the University of Iowa has shown that MnSOD activity is induced by hydroxytyrosol (Sarsour, AGE 22), and that MnSOD activity regulates glucose consumption during cellular proliferation. A. 5 2 MnSOD Fold Change MnSOD Activity Fold Change Actin B. CuZnSOD Activity AdBgl II AdMnSOD Hydroxytyrosol (µm) Hydroxytyrosol (µm) Catalase CuZnSOD GPx Actin 2 AdBgl II AdMnSOD 8 Cell Number (X5) Glucose Cosumption (pg cell-h-) 3 MnSOD Activity Fold Change 8 3 Days 2 AdBgl II AdMnSOD Hydroxytyrosol (µm) 8 2 AdBgl II AdMnSOD Figure : MnSOD activity regulates a metabolic switch iniluencing cellular proliferation. One hundred MOI of adenoviruses carrying CMV-promoter driven mouse or human MnSOD cdna (for MnSOD overexpression; AdMnSOD) were used to infect asynchronous cultures of (A) MnSOD ( / ) MEFs and (B) MB23 cells. AdBgl II represents non-replicative adenoviral vector without MnSOD cdna included as a control for adenoviral infections. Glucose consumption and cell numbers were measured at 9 h post-infection for MEFs (2A), and 72 h post-infection for MB23 (2B). Asterisk indicates significant differences in glucose consumption rate and cell numbers in MnSOD over-expressing vs. control and AdBgl II infected cells; n = 3, P <.5. D. 5 5 Days 2 MnSOD mrna Levels C. Hydroxytyrosol (µm) Cell Number (X5) Glucose Cosumption (pg cell-h-) B. Increased glucose metabolism in the presence of oxygen (aerobic glycolysis) is a hallmark of cancer cells known as the Warburg Effect (Bensinger 22). The Warburg Effect shifts the metabolism of cancer cells away from mitochondrial regulation. Dr. Sarsour proposed that MnSOD plays a role in relation to the Warburg effect that may occur in other high glucose environments such as diabetes. In addition, Dr. Karagiannis at the Baker IDI Research Institute examined the expression of genes involved in the A. 8 2 Figure 7: Hydroxytyrosol increases MnSOD activity in quiescent NHFs. Immunoblotting and gel-electro-phoresis assays for MnSOD protein levels and activity in quiescent NHFs that were incubated with HT for A 3, and B 5 and 3 days. Monolayer quiescent cultures of NHFs were fed with HTcontaining fresh media every 3 days. Actin protein levels were used for loading correction. Sodium cyanide was used to distinguish between MnSOD and CuZnSOD activities. C Quantitative RT-PCR assay measuring MnSOD mrna levels in 3-day control and HT-treated quiescent NHFs; fold change was calculated relative to 8S and untreated control. Asterisks indicate significant difference between control and HT-treated cells. n = 3; p <.5. D Immunoblot analysis of antioxidant enzymes at the end of 3-day HT-treated quiescent NHFs.

8 Page 8 Gene Name Gene Symbol Fold Change Up-regulated SLCA solute carrier family (glutamate/neutral amino acid transporter), member.28 C2orf5 chromosome 2 open reading frame BBC3 BCL2 binding component 3 2. VEGFA vascular endothelial growth factor A 2.5 TP53 tumor protein p CASP7 caspase 7, apoptosis-related cysteine peptidase ME malic enzyme, NAPD(+)-dependent, cytosolic AKT3 v-akt murine thymoma viral oncogene homolog 3 (protein kinase B, gamma) 2. CASP caspase, apoptosis-related cysteine peptidase.87 CASP8 caspase 8, apoptosis-related cysteine peptidase.2 Down-regulated PFKFB2 -phosphofructo-2-kinase/fructose-2,-biphosphatase ACLY ATP citrate lyase -. SREBF sterol regulatory element binding transcription factor -.9 PFKFB -phosphofructo-2-kinase/fructose-2,-biphosphatase -.79 TFR2 transferrin receptor Table 2: Genes involved in the Warburg effect-signiiicant up-and down-regulated genes in malignant leukemic K52 cells treated with µm hydroxytyrosol. Warburg effect following treatment of K52 leukemic cells with µm hydroxytyrosol. Pre-treatment of cells with hydroxytyrosol resulted in differential expression of 3% of these genes. In summary, hydroxytyrosol and formulas containing hydroxytyrosol including, have demonstrated specific anti-diabetes effects including antioxidant effects and substantially reduced wound healing impairment following exposure of cells to high glucose. Hydroxytyrosol and treatment has also resulted in increased angiogenesis, regulation of glucose consumption, and significant up and down-regulation of Warburg effect-related genes involved in glucose metabolism (aerobic glycolysis). These anti-diabetes effects were carefully researched in cutting-edge research laboratories including a world-renowned research laboratory led by a leading diabetes researcher, Dr. Thomas Karagiannis, who has published numerous papers in peer reviewed journals. In addition, they were carefully researched by Dr. Ehab Sarsour, who has also published many papers in peer reviewed journals. McCord Research s investigation of the role of hydroxytyrosol and diabetes is far more extensive than has been revealed in this paper. The purpose of this document is to present some of our basic research while protecting the most protected findings. -containing products that include hydroxytyrosol represent high quality but relatively low cost, scientifically-based, effective treatments for diabetes that will offer hope to patients in need of affordable anti-diabetes therapies. References. K-H Yoon et al, Lancet 2; 38: Bem and Tomic-Canic, J Clin Invest 27; 7: Falanga, Lancet 25; 3: Hadi and Suwaidi, Vasc Health Risk Manag 27; 3: Marotte et al, J Clin Invest 2; 2: Kim, Cell Transplant 2; 9: Rafehi et al, Genes Nutr 22; 7: Paine, Biochem Pharmacol 2; 8: Sarsour, Cancer Res 22; 72: Sarsour, AGE 22; 3: Bensinger, Semin Cell Dev Biol 22; 23: McCord Research Copyright 25 McCord Research Disclaimer: The authors and the publisher of this work have made every effort to use sources believed to be reliable to provide information that is accurate and compatible with the standards generally accepted at the time of publication. The authors and the publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers use of, or reliance on, the information contained in this article. The publisher has no responsibility for the persistence or accuracy of URLs for external or third party Internet websites referred to in this publication and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. P57