Bromocriptine-QR Therapy on Sympathetic Tone and Vascular Biology in Type 2 Diabetes Subjects

Eastern Virginia Medical School84 enrolled

Overview

The main objective is to demonstrate the effects of early dopaminergic activation on the autonomic nervous system in subjects with newly diagnosed vs. established type 2 diabetes. The primary endpoint is the effect of Bromocriptine QR on changes in autonomic function measured by assessing sympathetic and parasympathetic function using conventional measures of autonomic function, including power spectral analysis of heart rate as well as peripheral autonomic function using sudorimetry and laser scanning of peripheral microvascular autonomic control.

This is an interventional, twenty-four week, randomized, double blind, placebo-controlled trial with bromocriptine QR in subjects with newly diagnosed and established type 2 diabetes mellitus (T2DM) to evaluate its effects on the cardiovascular and peripheral autonomic nervous system, as well as on inflammatory markers, the leptin/adiponectin system, hormonal levels of RAS and HPA axis, indices of insulin resistance, and measures of oxidative and nitrosative stress. Forty newly diagnosed diabetes subjects and 40 subjects with established diabetes will be enrolled in the study and each randomized to treatment with bromocriptine-QR or placebo. Secondary endpoints will demonstrate the effects of dopaminergic activation with Bromocriptine-QR on the regulation of Hypothalamic-Pituitary-Axis (HPA) axis hormones, on the plasma levels of markers of inflammation and oxidative/nitrosative stress in newly diagnosed vs. established type 2 diabetes subjects. The study will evaluate treatment effects on inflammatory markers, the Leptin/Adiponectin system, and hormonal levels of rennin-angiotensin system (RAS), aldosterone and cortisol. Specifically, the following markers of inflammation and oxidative/nitrosative stress: 1) C reactive protein (CRP), 2) interleukin-6, 12, and 10, 3) tumor necrosis factor (TNFalpha), 4) plasminogen activator inhibitor (PAI1), superoxide dismutase (SOD), Thiobarbituric acid reactive substances (TBARS) and Asymmetric dimethylarginine (ADMA) will be evaluated. A co-secondary objective of the study will be to assess the impact of Bromocriptine-QR vs Placebo on measures of insulin resistance and glycemic control (e.g., oral glucose tolerance test (OGTT) glucose and insulin, Matsuda index, Homeostasis Model Assessment-insulin resistance (HOMA-IR), Hemoglobin A1c (HbA1c).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Eligibility

Sex: ALLMin age: 30 YearsMax age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Type 2 diabetes subjects between the ages of 30 and 80 years of age, inclusive, at Screening * Hemoglobin A1c (HbA1c) ≤10.0% at screening * Male or female (female of child bearing age must use definitive contraceptive therapy) * Type 2 Diabetes Mellitus subjects on a stable anti-diabetes regimen of diet and/or metformin alone therapy or on metformin plus an insulin secretion enhancer (sulfonylureas, dipeptidyl peptidase 4 (DPP4) Inhibitors, Glucagon-like peptide (GLP-1) analogs) therapy for a 60 day period prior to randomization. Subjects with diabetes duration of ≥ 4 years must be using an insulin secretion enhancer (e.g. sulphonylureas (SU), DPP4, GLP-1 analog). Subjects must have a documented C-peptide level (either fasting or random) of \>2 ng/ml from the screening visit. Exclusion Criteria: * Presence of type 1 diabetes mellitus (defined as C-peptide \<1 ng /ml) * Type 2 diabetes mellitus subjects on insulin. * Use of prescription sympathomimetics, ergot alkaloid derivatives, or anti-migraine medications, dopamine2 (D2)-like receptor antagonists (e.g. metoclopramide, domperidone) or systemic corticosteroids * Uncontrolled hypertension (systolic BP \>160 or diastolic BP \> 100 at screening) or a history of orthostatic hypotension * History of significant gastroparesis * Presence of diabetic retinopathy that is more severe than "background" level * Presence of diabetic nephropathy, or renal impairment defined by blood urea nitrogen (BUN) \>40mg/dl and serum creatinine \> 1.4 mg/dl if female taking metformin, \>1.5 mg/dl. if male taking metformin, and \>1.6 mg/dl if not taking metformin * Presence of clinically significant peripheral or autonomic neuropathy that is clearly of non-diabetic origin * History of major macrovascular events such as myocardial infarction or cerebrovascular event such as stroke within the past 6 months. Other exclusions include coronary artery bypass graft or coronary angioplasty in the previous 3 months, unstable angina pectoris (chest pain at rest, worsening chest pain, or admission to the emergency room or hospital for chest pain) within the previous 3 months, or seizure disorders. * Active infection (e.g., human immunodeficiency virus (HIV), hepatitis), or a history of severe infection during the 30 days prior to screening * Major surgical operation during the 30 days prior to screening * Cancer, other than non-melanoma skin or non-metastatic prostate cancer, within the past 5 years * Uncontrolled or untreated hypothyroidism as evidenced by thyroid stimulating hormone (TSH) concentrations \>4.8 µU/ml * Other serious medical conditions which, in the opinion of the investigator, would compromise the subject's participation in the study, including any concurrent illness, other than diabetes mellitus, not controlled by a stable therapeutic regimen, or conditions or abnormalities (e.g., blindness) that might interfere with interpretation of safety or efficacy data, or history of non-compliance * Clinically significant abnormalities on screening laboratory evaluation, unless approved by the Sponsor * Abnormalities of liver function defined as any liver enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT), serum glutamic-pyruvic transaminase (SGPT), Serum glutamic oxaloacetic transaminase (SGOT) greater than 3 times the upper limit of normal * History of New York Heart Association (NYHA) Class III-IV congestive heart failure. * Concurrent participation in another clinical trial with use of an experimental drug or device within 30 days of study entry. * History of alcohol or substance abuse or dementia * Pregnant or lactating women. Women of childbearing potential must have a negative pregnancy test at screening. Women who become pregnant will be discontinued from the study. * Known hypersensitivity to any of the formulation components * Working rotating, varying or night shifts * Use of unapproved herbal supplements that may be associated with a risk of cardiovascular events (such as ephedra, yohimbe etc) * Patients who have started therapy with an erectile dysfunction drug within 2 weeks prior to screening; patients may not begin treatment with an erectile dysfunction drug during the study period; patients currently taking erectile dysfunction drugs should do so only under medical supervision. * Donation of blood in the previous 30 days. Blood donation is also not allowed during the study or for 30 days after completion of the study.

Outcomes

Primary Outcomes

Change in E/I Ratio From Baseline to Endpoint After 24 Weeks of Intervention With Bromocriptine QR vs Placebo

Cardiac Autonomic Reflex Tests (CARTs) based on heart rate variations are the deep breathing test (E/I ratio), the lying to standing test (30:15 ratio) and the Valsalva maneuver (Valsalva ratio). These tests require a continuous recording of heart rate by either a simple electrocardiograph (ECG), subsequently elaborated via a specialist software. It is essential to inspect the ECG trace (on paper or monitor) in order to exclude artifacts or any type of arrhythmias from the calculations. Expiration/Inspiration (E/I) ratio: Standardized CART that measures parasympathetic control of the HR. The subject in a supine or sitting position is asked to breathe deeply at six breaths per minute (5 seconds in and 5 seconds out) for one minute. The E/I ratio is obtained by calculating the ratio between the average of the 3 longest RR intervals during expiration and the average of the 3 shortest RR intervals during inspiration.