The Effect of Linagliptin on Mitochondrial and Endothelial Function

Study Overview
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Brief Summary
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Investigators propose to examine the effect of 12 weeks of Linagliptin, a diabetes drug, treatment on inflammation as well as vascular and mitochondrial function in diabetic patients. Investigators hypothesize that Linagliptin will reduce the proinflammatory state, improve endothelial function, increase the blood flow at the muscle microcirculation level and improve mitochondrial function. In this study, investigators will perform tests that evaluate the function of small and large blood vessels by employing ultrasound and laser doppler techniques. In addition MRI scans that evaluate the mitochondrial function of the lower extremity muscles at rest and during exercise will also be employed. Forty subjects with Type 2 diabetes will be studied for twelve weeks and half of them will be randomly assigned to receive linagliptin while the other half will receive placebo. All tests will be performed at the beginning and the end of the study.

Conditions
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Type II Diabetes Mellitus

Intervention / Treatment
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* Drug: Linagliptin
* Drug: Placebo
* Other: Microcirculation testing
* Other: Macrocirculation testing
* Other: MRI Scans


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with T2DM whose medical or lifestyle treatment regimen is stable and not expected to be changed during the study period. Patients will be considered stable on their treatment regimen if there have not been any changes in the type of their antidiabetic medications over the past 3 months and/or there have not been any changes in their blood glucose levels that have caused them to see their health care provider more often than usual over the preceding three months. The diagnosis of T2DM will be according to the American Diabetes Association criteria. Subjects previously diagnosed with T2DM will not require confirmatory testing. Age 30-70 years Patients on insulin should be on a stable insulin regimen for at least 4 months prior to enrollment. Patients on antidiabetic treatment will be eligible if they are stable and no change in their treatment is planned for the next three months while they are in the study. HBA1c ≤ 10.0 Exclusion Criteria: Patient with unstable diabetes that has resulted in hyperosmolar coma, DKA, and/or documented increase or decrease in HbA1c of more than 2.0% within the previous 6 months Treatment with DPP4 Inhibitors or GLP-1 agonists. Patients who discontinued such treatment should be at least free for a 3-month period. Severe proliferative retinopathy that renders the subject legally blinded Previously intermittent claudication or diagnosed severe peripheral arterial disease requiring intervention. History of Deep Vein Thrombosis (DVT) within the past 3 months. Significant limb swelling due to lymphedema Previous diagnosis of severe gastroparesis diabeticorum due to autonomic neuropathy that has necessitated hospital admission Presence of non-healing foot ulceration due to severe peripheral diabetic neuropathy History of pancreatitis Documented diabetic nephropathy manifested as macro-albuminuria before enrollment in the study, (2 of 3 urine specimens collected within a 3-6 month period with urine albumin> 300 ug/mg creatinine - according to the ADA position statement) Smokers. Smokers will be defined as any subject who reports tobacco use during the three months before to study enrollment. Active or uncontrolled cardiovascular disease as follows: Myocardial infarction, or angina within 12 months of study participation Arrhythmia (uncontrolled, highly symptomatic, requires treatment or life-threatening). Patients with congestive heart failure requiring pharmacologic management, particularly when accompanied by hypoperfusion and hypoxemia due to unstable or acute failure, are at increased risk of lactic acidosis. Stroke or transient ischemic attack within 12 months of study participation Uncontrolled hypertension: SBP> 180 mmHg or DBP> 105 mmHg (2 abnormal readings during visit) Liver disease (AST, ALT Alk Phos levels >2x upper normal limit) at the time of enrollment Renal disease (creatinine > 2 mg/dL and/or estimated GFR <30 mL/min, history of dialysis, nephrotic syndrome) at the time of enrollment. Severe dyslipidemia (triglycerides>600 mg/dL or cholesterol >350 mg/dL) Subjects with hypertriglyceridemia may be retested in 2-3 weeks as the values can fluctuate tremendously within a few days. In the event that the retested value allows the patient to be enrolled, a planned deviation will be submitted to the CCI. Any other serious chronic disease requiring active treatment. Pregnancy or Lactation Females of childbearing potential not using an effective form of birth control as determined by the investigators. Subjects on any of the following medications: Systemic (not inhaled) Glucocorticoids Antineoplastic agents Rifampin Patient is known to have a history of immunodeficiency diseases, including a positive HIV (ELISA and Western blot) and/or positive Hepatitis B surface antigen (HBsAg) or Hepatitis C test result in the past. History of drug or alcohol abuse within the 12 months prior to dosing or evidence of such abuse as indicated by the laboratory assays conducted during the screening or baseline evaluations. Acute or chronic metabolic acidosis, including diabetic ketoacidosis. History of hypersensitivity reaction to linagliptin (such as urticaria, angioedema, or bronchial hyperreactivity) or metformin. Contraindications to MRI: Medically unstable or hematologic, renal, or hepatic dysfunction, cardiac pacemaker, Intracranial clips, metal implants, or external clips within 10 mm of the head, Metal in eyes. Pregnant or nursing women - Claustrophobia.

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Linagliptin<br>Subjects given Linagliptin | Drug: Linagliptin<br> <br> * Other names: Tradjenta;Other: Microcirculation testing<br>* The endothelial function of the micro-circulation will be assessed by measuring the hyperemic response of the vessels in the superficial skin of the forearm after the iontophoresis of acetylcholine. The endothelium independent vasodilation will be assessed by the iontophoresis of sodium nitroprusside. Laser Doppler perfusion imaging will be used to measure relative changes in flow velocity.Visible and NIR Medical Hyperspectral Imaging (MHSI) data will be collected with a HyperMed OxyView MHSI System (HyperMed, Inc., Watertown, MA). MHSI images will be obtained from same forearm area where the iontophoresis of acetylcholine and sodium nitroprusside will be performed, before and after the iontophoresis test.<br>Other: Macrocirculation testing<br>* Use ultrasound to measure brachial artery flow mediated vasodilation (FMD, endothelium-dependent vasodilation) and nitroglycerin induced dilation (NID, endothelium-independent vasodilation).<br>Other: MRI Scans<br>* Phosphorus-31 MRI data will be obtained during an exercise protocol. Muscle oxygenation will be measured using the blood oxygenation level-dependent magnetic resonance imaging (BOLD MRI) technique after induced hyperemia.<br>|
| Placebo Comparator: Sugar pill<br>Subjects given sugar pill/placebo | Drug: Placebo<br> <br> Other: Microcirculation testing<br>* The endothelial function of the micro-circulation will be assessed by measuring the hyperemic response of the vessels in the superficial skin of the forearm after the iontophoresis of acetylcholine. The endothelium independent vasodilation will be assessed by the iontophoresis of sodium nitroprusside. Laser Doppler perfusion imaging will be used to measure relative changes in flow velocity.Visible and NIR Medical Hyperspectral Imaging (MHSI) data will be collected with a HyperMed OxyView MHSI System (HyperMed, Inc., Watertown, MA). MHSI images will be obtained from same forearm area where the iontophoresis of acetylcholine and sodium nitroprusside will be performed, before and after the iontophoresis test.<br>Other: Macrocirculation testing<br>* Use ultrasound to measure brachial artery flow mediated vasodilation (FMD, endothelium-dependent vasodilation) and nitroglycerin induced dilation (NID, endothelium-independent vasodilation).<br>Other: MRI Scans<br>* Phosphorus-31 MRI data will be obtained during an exercise protocol. Muscle oxygenation will be measured using the blood oxygenation level-dependent magnetic resonance imaging (BOLD MRI) technique after induced hyperemia.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phosphocreatine (PCR) Recovery Time After Exhaustive or up to 6 Minutes of Leg Exercise. | Change in the time to phosphocreatine recovery between the baseline visit and post-treatment visit following the graded exercise test. | Baseline and 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Muscle Oxygenation Recovery Time | Change in muscle oxygenation after ischemia inducing occlusion for 4 minutes. | Baseline and 12 weeks | 
| Changes in Vascular Reactivity in the Micro- and Macro-circulation. | Change in markers of macro- and microvascular function from the baseline visit to the post-treatment visit between the two groups. | Baseline and 12 weeks | 
| Changes in SDF1-α and Substance P |  | Baseline and 12 weeks | 
| Changes in Circulating Endothelial Progenitor Cell Phenotypes | The measurements of the various EPC phenotypes were performed at the Beth Israel Deaconess Flow Cytometry Core Facility. Immunofluorescent cell staining was performed on peripheral blood with the use of the fluorescent conjugated antibodies. 1.000.000 events per sample were acquired using a FACS LSR II analyzer (Becton Dickinson, Franklin Lakes, NJ, USA) and the results were analyzed using the Beckman Coulter Kaluza analysis software (Beckman Coulter Inc., Brea, CA, USA). | Baseline and 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glucose, Type II Diabetes Mellitus, Diabetes, Metabolism, Linagliptin, Tradjenta