Clinical Research Directory

Saccharin and Acesulfame Potassium Consumption and Glucose Homeostasis in Older Adults With Prediabetes

Animal and observational research in humans suggest that specific types of non-nutritive sweeteners (NNS) may impair glycemic control. However, whether NNS consumption impacts glucose homeostasis in middle-aged/older adults with prediabetes is unknown, and potential mechanisms by which this could occur have yet to be identified. The overall objective of this R21 proposal is to establish proof-of-concept for alterations in glucose homeostasis following intake of saccharin, but not acesulfame potassium, in middle-aged/older adults with prediabetes compared to a eucaloric diet with no NNS.

The Importance of Insulin Action in the Brain for the Immune System During Physical Activity-Overweight

The goal of this clinical trial is to clarify the interaction of central insulin action and physical activity with the immune system. Therefore, participants will undergo bicycle spiroergometer tests. This approach will be compared between days with insulin delivery to the brain as nasal spray and days with placebo spray. In another trial (NCT06552130) lean participants already have been tested. Significant effects on circulating cytokines could be identified. In this amendment, overweight persons in which brain insulin resistance is expected will be tested.

A Study to Evaluate the Effect of Retatrutide on Insulin Secretion and Insulin Sensitivity in Adult Participants With Type 2 Diabetes Mellitus

The primary objective of Study GZQG is to compare the effect of retatrutide and placebo on total clamp disposition index (cDI) after 28 weeks of treatment.

Aging Resilience Through Microbiota Optimization and Regulation

Sarcopenia, characterized by the progressive loss of muscle mass and strength in older adults, is a key factor in health deterioration. It affects 15% of people between 65 and 80 years old and over 50% of those over 80, compromising autonomy and increasing the risk of diseases. Sarcopenia not only impacts muscle function but also bone health, mobility, and is associated with cardiometabolic diseases and cognitive decline. It has been proposed that changes in the gut microbiota in aging individuals, known as gut dysbiosis, contribute to sarcopenia. Species diversity decreases, and bacterial representation is altered, which could impair muscle function through various pathways, such as mitochondrial dysfunction, chronic inflammation, and disruption of protein synthesis. Muscle function loss is strongly associated with cognitive and metabolic impairment in older adults. Recently, it has been demonstrated that fecal microbiota transplantation (FMT) is an effective procedure for modulating gut microbiota and has proven highly effective in managing cases of Clostridium difficile-associated chronic diarrhea. The main objective of this project is to carry out FMT from young, physically active donors to a cohort of older adults to evaluate its effect on muscle, cognitive, and metabolic function. Why donors who exercise? There is growing evidence that gut microbiota diversity is increased in young, physically active individuals. The FMT is planned to be administered through lyophilized microbiota capsules. By restoring microbial diversity, it is expected to improve the quality and function of skeletal muscles, leading to greater cognitive and metabolic resilience. This project has great potential to develop an innovative approach for treating highly debilitating diseases that affect older adults, based on the lyophilization and encapsulation of gut microbiota from young, trained donors, which can be easily stored in a conventional freezer. Due to the high percentage of older adults worldwide and the high prevalence of sarcopenia within this age group, the aim of the project is to address a significant public health issue with a large target population eager for options to promote muscle health, functional autonomy, as well as cognitive and metabolic well-being.

The Effect of Colchicine, on Insulin Sensitivity in Individuals With Type 1 Diabetes and Systemic Low-grade Inflammation

The aim for this clinical trial is to evaluate if colchicine in addition to standard of care improves insulin sensitivity in individuals with type 1 diabetes, systemic low-grade inflammaiton and reduced insulin sensitivity. The insulin sensitivity will be evaluated by a hyperinsulinemic, euglycemic clamp.

The Sweet Kids Study (Stevia on Weight and Energy Effect Over Time)

This is an 8 to14-week three-arm randomized controlled in children 8 to 12 years old. The main purpose of the study is to evaluate if stevia has benefits for weight control and metabolic function relative to caloric sweeteners, and whether it provides benefits in this regard similar to water.

Impact of Circulating and Tissue-specific Lipids on Vascular Function and Insulin Sensitivity in Chronic Night Shift Workers

People who experience repeated bouts of circadian misalignment, such as shift workers, are at higher risk of cardiovascular disease (CVD) and Type 2 diabetes (T2D) compared to daytime workers. However, the mechanism(s) by which shift work and associated circadian misalignment increase CVD and T2D risk are unknown. This project will examine whether elevated plasma lipids are a mechanism by which circadian misalignment impairs vascular function, insulin sensitivity, glucose homeostasis and muscle lipid accumulation, which could be targeted to prevent and treat cardiometabolic disease in people who chronically experience circadian misalignment, which includes more than 20% of the US workforce.

The Importance of Insulin Action in the Brain for the Immune System During Physical Activity

The goal of this clinical trial is to clarify the interaction of central insulin action and physical activity with the immune system. Therefore, participants will undergo bicycle spiroergometer tests. This approach will be compared between days with insulin delivery to the brain as nasal spray and days with placebo spray.

Non-Nutritive Sweetener Consumption and Glucose Homeostasis in Older Adults With Prediabetes

Animal and observational research in humans suggest that specific types of non-nutritive sweeteners (NNS) may impair glycemic control. However, whether NNS consumption impacts glucose homeostasis in middle-aged/older adults with prediabetes is unknown, and potential mechanisms by which this could occur have yet to be identified. The overall objective of this R21 proposal is to establish proof-of-concept for alterations in glucose homeostasis following intake of sucralose, but not aspartame, in middle-aged/older adults with prediabetes compared to a eucaloric diet with no NNS.

Effect of Physiologic Insulin Administration on Insulin Sensitivity and Cognition

The goal of this clinical trial is to determine if a weekly delivery of insulin at short intervals lasting up to 2 hours can improve insulin sensitivity and cognition in adults with Alzheimer's Disease. It will also provide information about the safety and feasibility of this intervention. The main questions it aims to answer are: Does the intervention improve insulin sensitivity (how the body uses glucose)? Does the intervention improve cognition, measured by the Montreal Cognitive Assessment (MoCA) and the Revised Memory and Behavior Problems Checklist (RMBPC)? What changes occur in brain glucose uptake (FDG-PET)? Participants will: Receive the intervention once a week for 6 months, with each session lasting up to 2 hours Complete cognitive assessments. Adverse events will be assessed throughout the study.

Physical Activity and Insulin Sensitivity Dynamics

The study investigates the role of one single bout of exercise in mediating enhancement of muscle insulin sensitivity following a single bout of exercise. Furthermore, the study is aiming to elucidate the temporal development in insulin signaling, at the early timepoints of insulin stimulation that may be responsible for the enhanced muscle insulin sensitivity. This will be investigated in young healthy males subjected to a one-legged knee-extensor exercise followed by a hyperinsulinemic-euglycemic clamp, a setup known to enhance muscle insulin sensitivity.

Effect of Endoscopic Sleeve Gastroplasty in Patients With Obesity and MASH: A Randomized Controlled Trial

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease globally. While weight loss through lifestyle modification is the standard treatment, most patients regain weight limiting ultimate improvement in liver disease. On the other end of the spectrum, bariatric surgery has shown promise in the treatment of MASLD/metabolic dysfunction-associated steatohepatitis (MASH) due to its efficacy in inducing weight loss. Nevertheless, its adoption has been hindered by the perceived invasiveness of surgery. Over the past decade, endoscopic sleeve gastroplasty (ESG) has gained recognition as a promising minimally-invasive approach to weight loss. The procedure involves utilizing a Food and Drug Administration (FDA)-authorized endoscopic suturing device to reduce the gastric volume by 70%. Studies reveal that ESG is associated with approximately 18.2% weight loss at one year after the procedure, with sustained results for at least 10 years. Nevertheless, the effect of ESG on MASH remains unknown. In this study, the investigators will compare ESG + lifestyle modification versus lifestyle modification alone in treating histologic MASH. The study will randomize patients to one of two different treatment options: ESG + lifestyle modification or lifestyle modification alone.

Insulin Sensitivity and Testosterone Response to Aerobic Exercise Versus Added Sugar Elimination in Polycystic Ovary Syndrome Women

the aim of this study is to investigate the effect of aerobic exercise versus the effect of added sugar elimination on the insulin sensitivity and testosterone levels in females with polycystic ovarian syndrome via measuring the level of 6 hours fasting HOMA-IR and free testosterone before and after 3 months from starting the protocol. All patients were diagnosed as polycystic ovary syndrome with low insulin sensitivity levels

Countermeasures to Circadian Misalignment

Insufficient sleep and circadian misalignment are independent risk factors for the development of obesity and diabetes, yet few strategies exist to counter metabolic impairments when these behaviors are unavoidable. This project will examine whether avoiding food intake during the biological night can mitigate the impact of circadian misalignment on metabolic homeostasis in adults during simulated night shift work. Findings from this study could identify a translatable strategy to minimize metabolic diseases in populations that include anyone working nonstandard hours such as police, paramedics, firefighters, military personnel, pilots, doctors and nurses, truck drivers, and individuals with sleep disorders.

Understanding Dose Related Effects of Strawberry

The proposed research is designed to extend previous research findings building on the knowledge of strawberries as fruits that support a healthy immune and vascular system. The proposed research leverages a recently funded proposal by the USDA to study in greater depth inflammation, glucoregulation and oxidative stress defense and their relation to improving endothelial function and insulin sensitivity. Before and after strawberry intake, blood samples will be collected for monocyte (immune cells and source of inflammatory cytokines) isolation and activation via changes in cellular NF-κB and Nrf-2 (key transcription factors of inflammation/oxidative stress defense) status along with products of their activation (ie., plasma cytokines). Because inflammation and oxidative stress impairs endothelial function and insulin sensitivity, acutely and chronically, investigators will also study changes in vascular and insulin sensitivity status, assessing changes in vascular adhesion molecules, endothelial responsiveness through flow mediated vasodilation (ie., FMD) and insulin sensitivity using the Liquid Meal Tolerance (LMTT) if intravenous glucose tolerance test (IVGTT) method cannot be used due to supply chain issues of sterile Dextrose. Glucoregulation will be assessed by placing a Continuous Glucose monitoring (CGM) machine (Dexcom-6) to participants for 10 days at the beginning and at the end of the study period of intervention. The study will be a randomized, double-blinded, 3-arm parallel, 4-week, dose-response study. Individuals with chronic low grade inflammation will be sought to test the anti-inflammation - vaso-relaxing - insulin sensitivity effects of strawberry.

MANATEE-T1D: Metformin ANd AutomaTEd Insulin Delivery System Effects on Renal Vascular Resistance, Insulin Sensitivity, and Cardiometabolic Function in Youth With Type 1 Diabetes

Diabetic kidney disease and cardiovascular disease remain the leading causes of morbidity and mortality in people with type 1 diabetes and are exacerbated with longer duration of diabetes and time outside goal glycemic range. Yet, type 1 diabetes is a complex disease with pathophysiology that extends beyond beta-cell injury and insulin deficiency to include insulin resistance and renal vascular resistance, factors that accelerate cardiovascular disease risk. We have shown that metformin improved peripheral insulin sensitivity and vascular stiffness in youth with type 1 diabetes on multiple daily insulin injections or standard insulin pumps. However, metformin's effect on kidney and endothelial outcomes, and the effects of type 1 diabetes technologies, with or without metformin, on any cardiovascular or kidney outcome, remains unknown. Automated insulin delivery systems combine an insulin pump, continuous glucose monitor, and control algorithm to modulate background insulin delivery and decrease peripheral insulin exposure while improving time in target range and reducing hypoglycemia. We hypothesize that automated insulin delivery systems, particularly when combined with metformin, may modulate renal vascular resistance and insulin sensitivity, thereby impacting cardiometabolic function. MANATEE-T1D is a randomized, double-blind, placebo-controlled trial of 4 months of metformin 2,000 mg daily in 40 youth aged 12-25 years with type 1 diabetes on automated insulin delivery systems vs. 20 control youth with type 1 diabetes on multiple daily injections plus a continuous glucose monitor or an insulin pump in manual mode plus a continuous glucose monitor which will assess for changes in calculated renal vascular resistance and gold standard measures of whole-body and adipose insulin sensitivity, arterial stiffness, and endothelial function.

Pubertal Blockade and Estradiol Effects on Cardiometabolic Health for Transitioning Youth

To evaluate the effect of estradiol with or without a prior gonadotropin releasing hormone analogue on insulin sensitivity and vascular function in transgender females compared to cisgender controls.

Evaluation of Molecular Hydrogen Supplementation to Enhance the Efficacy of Weight Loss Retreat in Overweight and Obese Adolescents

This randomized controlled trial evaluates whether molecular hydrogen supplementation enhances the effectiveness of a 4-week weight loss retreat in overweight and obese adolescents. Outcome measures include: body composition, physical status, blood samples (insulin sensitivity, lipid profiles, markers of oxidative stress and inflammation) and autonomic nervous system function.

Pulses Consumption and Its Role in Managing Systemic Inflammation, Insulin Sensitivity and Gut Microbiome in Human

Objective 1: Characterize indices of systemic inflammation and gut microbiota composition and function after chronic (12 weeks) intake of pulses compared to control diet in human OW/OB-IR participants. Objective 2: Characterize dietary- and microbial-derived metabolite pools after regular intake of pulses (12 weeks) in human participants with OW/OB-IR compared to control diet. Objective 3: Characterize cognitive functioning after chronic (12 weeks) intake of pulses compared to control diet in human OW/OB-IR participants.

Mechanisms of Ultrasound Neuromodulation Effects in Diabetes

This study aims to evaluate the effect of hepatic ultrasound treatment on changes from baseline in whole-body insulin sensitivity during a hyperinsulinemic, euglycemic clamp (HE Clamp).

Evaluating the Efficacy of Topical Insulin for the Restoration of Ocular Surface Interface in Dry Eye Disease.

This is a parallel randomized controlled trial for the treatment of dry eye disease. The main objective is to investigate the efficacy and safety of the use of insulin eye drops in the control of moderate-severe dry eye disease. Topical insulin drops will be compared to artificial tears in improving the ocular surface interface in patients with dry eye disease over 1 year period.

Metabolic Adaptations to Weight Loss With and Without Exercise

Study Purpose: The combination of caloric restriction and exercise is the most common first-line treatment for obesity-related disorders, yet we know very little about how these two very different treatments work together. A deeper understanding about mechanisms underlying the health benefits of adding exercise to a weight loss program will not only aid efforts to optimize more effective lifestyle interventions, but it can also uncover novel targets for the treatment/prevention of obesity-related diseases. Although a reduction in body fat is the fundamental adaptation to weight loss, we know almost nothing about the effects that adding exercise has on structural and functional changes within fat tissue that may further enhance metabolic health. This is very important because many obesity-related metabolic health complications are tightly linked with abnormalities in abdominal fat tissue. We argue exercise-induced modifications in abdominal fat tissue will reveal persistent health benefits even if some weight is regained Study Summary: 10% Weight Loss Phase - Subject participation in the study will involve a series of metabolic tests before, at midpoint, and after undergoing a 10% weight loss program (with or without exercise training depending on group randomization). During this, subjects will be randomized into one of two different experimental groups: 1. Moderate Intensity Continuous Training (MICT) exercise group 2. No exercise (control) group Follow-up Phase: After completing the metabolic testing post-weight loss, all study-related diet and exercise supervision will end and subjects will be free to make their own choices regarding diet and exercise/physical activity behavior. Subjects will then be asked to complete follow-up testing at 2-, 4- and 6- months post-weight loss. Total involvement in the study for each subject will likely be about 10-13 months (4-7 months during weight loss phase, 6 months during follow-up phase).

The Acute T-Rex (Timing of Resistance Exercise) Study

The primary aim of this study is to evaluate if a single bout of AM vs PM resistance exercise has different effects on insulin sensitivity and sleep. A randomized cross-over trial be used to compare resistance exercise at two different times of the day. Each condition will take place in a laboratory setting. Each condition will consist of exercise, overnight sleep, and oral glucose tolerance tests the following day. The AM exercise will occur \~1.5 hours after habitual wake, and PM exercise will occur \~11 hours after habitual wake. After a 2-6 week washout, participants will complete the other condition. The hypothesis is that PM exercise will be more beneficial than AM exercise in improving insulin sensitivity. This study could identify if there is a better time of day to perform resistance exercise to decrease risk of developing Type 2 Diabetes Mellitus.

Effect of GLP1 Receptor Agonist on Brain Insulin Responsiveness

The overarching goal of the current study is to investigate the effect of GLP-1 on brain insulin responsiveness in a randomized, single-blinded, within subject cross-over study design. To this end, investigators will compare the effect of the administration of semaglutide versus placebo, followed by an fMRI with administration of intranasal insulin or placebo.