Acute Effect of HP-211 (Axulin) on Blood Glucose and Serum Insulin Responses in Healthy Lean and Overweight Humans

Acute Effect of HP-211 (Axulin) on Blood Glucose and Serum Insulin Responses in Healthy Lean and Overweight Humans

Acute Effect of HP-211 (Axulin) on Blood Glucose and Serum Insulin Responses in Healthy Lean and Overweight Humans

Blood sugar levels are controlled by insulin, a hormone made by cells in the pancreas. After a meal, carbohydrates are broken down into glucose (blood sugar) which is absorbed from the intestine into the blood leading to a rise in glucose which triggers the secretion of insulin. Insulin binds to cells in the liver, muscle and fat, triggering them to take up glucose and bring the blood glucose level back to normal. A high blood sugar level is known as diabetes. The most common form of diabetes, type 2 diabetes, is caused by insulin resistance; that is, a reduced ability of insulin to stimulate glucose uptake into cells. The body compensates for insulin resistance by making more insulin; type 2 diabetes occurs when the pancreas can no longer make enough insulin to control blood glucose. The high blood glucose and insulin levels lead to long-term complications such as heart attacks, kidney failure, reduced sensation and poor circulation in the feet and legs. Reducing blood glucose levels with oral medications and insulin reduces risk of diabetic complications. There are several types of oral medications available for treating diabetes; however, they do not always control blood glucose adequately. In addition, these drugs have complications and are not used to treat insulin resistance and prediabetes - a condition when blood glucose is higher than normal but not high enough to be classified as diabetes. Prediabetes often progresses to diabetes over a period of months or years. Effective and safe treatments for prediabetes could prevent or delay the onset of diabetes. Axulin is a natural health product consisting of a mixture of extracts - derived from herbs and vegetables present in normal diets - which has been shown in cell culture and in animal studies to increase the ability of insulin to stimulate glucose uptake into cells. The active ingredient in Axulin is a botanical extract designated HP-211. Thus, HP-211 may reduce the blood glucose and insulin levels of subjects without diabetes after eating. HP-211 may also reduce glucose and insulin responses to a larger extent in insulin-resistant as compared to insulin-sensitive subjects. Subjects will take 0g, 2g, or 4g of capsules or tablets in the morning after an overnight fast; 40 minutes later they will consume 75g glucose dissolved in 300ml water. Blood glucose, insulin and fats will be measured before and for 2 hours after the glucose drink.

After consumption of a meal, pancreatic secretions of various digestive enzymes results in the breakdown of carbohydrates into monosaccharides including glucose. These sugars are subsequently absorbed through the intestinal lumen, resulting in an increased plasma glucose concentration. In response to high glucose levels, pancreatic beta-cells are stimulated to release the hormone insulin which circulates through the bloodstream and binds to insulin-responsive cells including adipocytes (fat tissue), myocytes (muscle tissue), and hepatocytes (liver). The resulting insulin-mediated signaling cascade initiates intracellular glucose uptake within peripheral tissues leading to a corresponding decrease in circulating plasma glucose. In insulin responsive cells glucose uptake stimulation begins after the binding of insulin to Insulin Receptors (IR), which are found on the membrane surface of cells in insulin responsive tissues such as fat, muscle and liver. The IR consists of an extracellular domain which binds to insulin, and an intracellular domain that has a protein tyrosine kinase activity. The binding of Insulin to the IR initiates a series of auto-phosphorylation events within the protein kinase domain that permit interaction and phosphorylation of downstream signaling proteins in the cell that mediate the cellular response to insulin. The resulting signaling complex includes proteins in the Insulin Receptor Substrate (IRS) family known as IRS-1 and IRS-2. These key targets of the insulin signaling pathway link IR activation to downstream signaling cascades that mediate intracellular processes including GLUT4-mediated glucose uptake. Prediabetes and Type II diabetes involve an impaired post-receptor response to insulin that hinders the glucose uptake response after meal consumption. Chronic hyperglycemia and the resulting compensatory hyperinsulinemia promote a cohort of acute and chronic sequelae including cardiovascular disease, liver complications, central nervous system degeneration and hyperglycemic osmotic stress. Axulin is a natural health product consisting of a mixture of extracts from herbs and vegetables present in normal diets which was identified by screening more than 100,000 compounds and extracts in a patented cell-culture based assay system targeting the IRS proteins. In vitro, Axulin's active ingredient, HP-211, has marked effects on the IRS-2 branch of the insulin signaling cascade to enhance downstream insulin signaling. HP-211 has been shown in animal models to increase glucose uptake in peripheral tissues and decrease circulating blood glucose and triglyceride concentrations. Regular supplementation of the diet with Axulin would be expected to reduce the incidence of associated prediabetic and diabetic complications, resulting in an increased quality of life for patients without resorting to current anti-diabetic prescription drugs such as metformin and others that may have substantial unwanted side effects in patients. HYPOTHESES Axulin will reduce postprandial glucose and insulin responses in a dose-dependent fashion in healthy subjects without diabetes. The reduction in glucose and insulin will be relatively greater in insulin-resistant than insulin-sensitive subjects. Subjects will take 0g, 2g, or 4g of capsules or tablets in the morning after an overnight fast; 40 minutes later they will consume 75g glucose dissolved in 300ml water. Blood glucose, insulin and triglycerides will be measured fasting and at intervals for 2 hours after the glucose drink.

Percentage change in the incremental area under the glucose response curve (AUC) after 75g glucose for capsules and tablets containing Axulin powder relative to the water control. Incremental AUC is the AUC below the curve above the fasting level; area below fasting is ignored. Percentage change will be calculated as 100 x (A-P)/P where A and P are the mean AUC's after Axulin and water control treatments, respectively. The blinded AUC results for the 6 treatments will be subjected to repeated measures analysis of variance (ANOVA) examining for the main effects of treatment and participant-group, and treatment*group interaction. After demonstration of significant heterogeneity among the 6 coded treatments, differences between individual means will be assessed using Tukey's test to adjust for multiple comparisons. The code will be broken after this analysis has been done. The percentage changes will be considered to be significant if the difference in mean AUC is significant.

Incremental area under the blood glucose response curve (AUC) is the AUC below the glucose response curve above the fasting level; area below fasting is ignored. The blinded AUC results for the 6 treatments will be subjected to repeated measures analysis of variance (ANOVA) examining for the main effects of treatment and participant-group, and treatment*group interaction. After demonstration of significant heterogeneity among the 6 coded treatments, differences between individual means will be assessed using Tukey's test to adjust for multiple comparisons. The code will be broken after this analysis has been done.

Incremental area under the serum insulin response curve (AUC) is the AUC below the insulin response curve above the fasting level; area below fasting is ignored. The blinded AUC results for the 6 treatments will be subjected to repeated measures analysis of variance (ANOVA) examining for the main effects of treatment and participant-group, and treatment*group interaction. After demonstration of significant heterogeneity among the 6 coded treatments, differences between individual means will be assessed using Tukey's test to adjust for multiple comparisons. The code will be broken after this analysis has been done.

Percentage change in the incremental area under the insulin response curve (AUC) after 75g glucose for the capsules containing Axulin powder relative to the water control. Incremental AUC is the AUC below the curve above the fasting level; area below fasting is ignored. Percentage change will be calculated as 100 x (A-P)/P where A and P are the mean AUC's after Axulin and water control treatments, respectively. The blinded AUC results for the 6 treatments will be subjected to repeated measures analysis of variance (ANOVA) examining for the main effects of treatment and participant-group, and treatment*group interaction. After demonstration of significant heterogeneity among the 6 coded treatments, differences between individual means will be assessed using Tukey's test to adjust for multiple comparisons. The code will be broken after this analysis has been done. The percentage changes will be considered to be significant if the difference in mean AUC is significant.

Insulinogenic Index is an index of the ability of a change in blood glucose to stimulate an increase in serum insulin. It is a unitless measure with higher numbers indicating improved beta cell function. It is calculated by dividing the change in serum insulin between 0 and 30 minutes by the change in blood glucose between 0 and 30 minutes.

Matsuda Insulin Sensitivity Index is an index of whole body insulin sensitivity derived from glucose and insulin responses after a 75g Oral Glucose Tolerance Test (OGTT). It is calculated by 10000 divided by the square root of (FG*FI*MG*MI) where FG is fasting glucose, FI is fasting insulin, MG is the mean AUC for blood glucose at 0, 30, 60, 90 and 120 minutes and MI is the mean AUC for serum insulin at 0, 30, 60, 90 and 120 minutes.

Insulin Secretion-Sensitivity Index-2 (ISSI-2) is an index of β-cell function with insulin secretion adjusted for whole body insulin sensitivity. It is calculated by the total area under the curve for serum insulin divided by the area under the curve for blood glucose, and that result times the Matsuda insulin sensitivity index (defined above).

Percentage change in blood glucose area under the curve (AUC) in lean participants compared to overweight participants.

Percentage change in blood glucose area under the curve (AUC) elicited by capsules compared to the same dose of tablets.

Inclusion Criteria: Participants taking stable doses (for at least 4 weeks of signing the consent form) of the birth control pill, thyroxin replacement therapy, statins, fibrates, cholesterol absorption inhibitors, anti-hypertensive medications, asprin, non-steroidal anti-inflammatories and/or mild anxiolytics or sedatives can be included. Exclusion Criteria: Fasting serum glucose >6.9mmol/L (124mg/dL) HbA1c >6.4% Fasting serum triglycerides >4.5 mmol/L (399 mg/dL) Fasting LDL cholesterol >4.99 mmol/L (192 mg/dL) Blood pressure >149 systolic or >89 diastolic Serum creatinine, or aspartate- or alanine transaminases >1.2 times upper limit of normal White cell count, red blood cell count, hemoglobin or hematocrit outside normal range Hospitalization for surgery or a medical condition within 3 months of signing the consent form Use of any drug to treat diabetes Use of medications other than those listed above or the presence of any condition which might, in the opinion of Dr. Wolever, either: 1) make participation dangerous to the subject or to others, or 2) affect the results Allergy or sensitivity to tarragon, chromium, escarole, lettuce, microcrystalline cellulose, inulin, food colouring (FD&C Yellow#5 and Blue#1) or vegetable-based capsules (silicon dioxide, titanium dioxide, hydroxypropylmethylcellulose)