Clinical Research Directory

Cross-Sectional and Longitudinal Studies of "Pre-Diabetes" in the Pima Indians

Insulin resistance and a defect in early insulin secretion are risk factors for the development of type 2 diabetes mellitus. A recent longitudinal analysis which tracked the development of diabetes demonstrated that both insulin action and early insulin secretion deteriorate as individuals progress from normal to impaired glucose tolerance and then to diabetes. These results suggest that both inherent (apparent in normal glucose tolerant subjects who progress to diabetes and likely to have a genetic basis) and acquired (evident as individuals progress from NGT to IGT to diabetes and possibly environmental in origin) defects in insulin action and secretion contribute to the pathogenesis of type 2 diabetes. To identify the genetic and environmental determinants of diabetes we are continuing to determine: (1) if there are genes that segregate with metabolic risk factors for diabetes which might therefore be genetic markers for type 2 diabetes and (2) the mechanisms mediating genetic and environmental determinants of insulin resistance and impaired insulin secretion. \<TAB\> Volunteers for this study will be admitted to the clinical research ward where they will undergo several tests to determine body composition, oral and intravenous glucose tolerance and in vivo insulin action. In addition, in selected subjects, adipose and/or skeletal muscle tissue will be obtained by percutaneous biopsy for in vitro studies of gene expression and insulin action in these tissues. A transformed lymphocyte cell line will be established for each subject as a permanent source of DNA for genetic studies. Genetic markers for type 2 diabetes and insulin resistance will be sought by typing each individual at positional and functional candidate loci in the hopes of finding an association between these loci and obesity, insulin secretion, insulin resistance and/or type 2 diabetes.

Trial of the Combination of Alpha-Lipoic Acid and Mirabegron in Women and in Men With Obesity

Background: Obesity and related illnesses cause at least 2.8 million deaths each year worldwide. Few treatments exist for obesity that are safe and widely available. A study drug (mirabegron \[MG\]) combined with a supplement (alpha-lipoic acid \[ALA\]) may help. Objective: To learn how MG and ALA can help the body process food. Eligibility: People aged 18 to 65 years with a body mass index between 30 and 45 kg/m2. Design: Participants will be screened. They will have a physical exam. They will have blood and urine tests and a test of their heart function. They will speak with a dietician. The study has two phases. Each phase begins with a 2-day stay in the clinic; then the participant will take the study drugs at home for about 4 weeks, followed by another 2-day stay in the clinic. They will also have outpatient visits about 2 weeks after each clinic stay. During the clinic stays, participants will undergo many tests: They will have a plastic tube (catheter) inserted into a vein in each arm. These will be used to draw blood and to infuse glucose (sugar) and insulin. They will have imaging scans. They will have a clear hard plastic shield placed over their head to measure oxygen and carbon dioxide as they breathe. Participants will take the study drugs at home. Both MG and ALA are taken by mouth with water. During one phase, participants will take MG plus a placebo. A placebo looks like the study drug but doesn t contain medicine....

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.

Identifying Risk for Diabetes and Heart Disease in Women

Background: \- Rates of diabetes and heart disease in women are increasing. Early recognition of risk could help women live longer and healthier lives. Race and ethnicity may affect the best kinds of tests to use to screen for these conditions. Researchers want to compare risk factors for diabetes and heart disease in African, African-American, and white women. Doing so may help identify the most effective screening test for each group. This study will look at healthy African, African-American, and white women who are federal employees and contractors. Objectives: \- To study risk factors for diabetes and heart disease in African, African-American, and white women. Eligibility: * Healthy African, African-American, and white women between 30 and 65 years of age who are federal employees or contractors. * For this study, African women must be born in Africa and have immigrated to the United States, and report that both parents are Africans. African-American women must self-identify as African-Americans, born in the United States, and have parents who both self-identify as African-American born in the United States. White women must self-identify as white and have parents who also self-identify as white. Design: * Participants will have four visits to study their risk factors for diabetes and heart disease. * The first visit is a screening visit. Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. They will also have an EKG test. Participants will also be shown how to fill out a 3-Day Food Record and wear an activity monitor called an accelerometer. The food record will keep track of how much participants eat for 3 consecutive days, including 1 non-working day. The accelerometer device will be worn for 3 days to monitor movement. * At the second visit, participants will have blood tests, an oral glucose tolerance test, and body fat measurements. They will also fill out questionnaires, review the food record, and have two imaging studies. * At the third visit, participants will have a longer glucose tolerance test. During the test, participants will receive both glucose and insulin and blood samples will be collected over several hours. Participants will receive lunch at the clinical center after the test. * At the fourth visit, participants will have a meal test. They will fast for 12 hours before the test. Participants will eat a specific meal and have blood samples taken during and after they eat. * Participants will discuss the results of these tests with the study doctors.

Dietary Macronutrients and Metabolic Markers

This prospective 12-week dietary intervention study evaluated the effects of a ketogenic diet on thyroid function and glucose-insulin metabolism in premenopausal women aged 30-50 years across different adiposity categories. Participants followed an individualized low-carbohydrate ketogenic diet designed to induce and maintain nutritional ketosis. Thyroid-related outcomes included thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4). Glucose-insulin metabolism was assessed using fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), and the homeostatic model assessment of insulin resistance (HOMA-IR). Changes in body mass and anthropometric parameters were also evaluated. Outcomes were assessed before and after the 12-week intervention and compared according to baseline BMI categories.

Human Models of Selective Insulin Resistance: Alpelisib, Part I

The goal of this clinical trial is to understand how the blood sugar-lowering hormone insulin works in healthy adults versus those who are at risk for type 2 diabetes. The study will use a drug called alpelisib, which interferes with insulin's actions in the body, to answer the study's main question: does the liver continue to respond to insulin's stimulation of fat production even when it loses the ability to stop making glucose (sugar) in response to insulin. Researchers will compare the impact of single doses of both alpelisib and placebo (inert non-drug) in random order (like flipping a coin) in study participants. Participants will be asked to stay twice overnight in the hospital, take single doses of alpelisib and placebo (one or the other on each of the two hospital stays), and receive intravenous (into the vein) infusions of non-radioactive "tracer" molecules that allow researchers to measure the production of glucose (sugar) and fats by the liver. Measurements will be done both while participants are fasting (not eating or drinking other than water) and while consuming a standardized diet of nutritional beverages. The objective is to evaluate the effect of lowering insulin levels, while maintaining constant mild hyperglycemia, on plasma glucose and lipid levels.

The Effects of Cognitive Behavioral Therapy on Insulin Resistance in People With HIV

The goal of this clinical trial is to learn if depression treatment improves insulin resistance, or how the body uses insulin to lower blood sugar, in people with HIV on HIV treatment. Researchers will compare an internet-based (online) depression treatment program called cognitive behavioral therapy with depression education. In the online group, participants will undergo 9 weekly treatment sessions. The education group will receive learning materials about depression and will be monitored every month. All participants will have 4 study visits over 12 months.

FABP4 Response After Roux-en-Y Gastric Bypass

This retrospective observational cohort study examined serum fatty acid-binding protein 4 (FABP4) dynamics in 28 adults who underwent Roux-en-Y gastric bypass (RYGB), followed at baseline, 3 months, and 6 months. Anthropometric, metabolic, and inflammatory parameters were assessed alongside FABP4, fasting GLP-1, and PYY. Patients were classified as FABP4 responders (decrease from baseline to 6 months) or rebound/non-responders. The study investigated whether FABP4 trajectory after RYGB is associated with the magnitude of weight loss, systemic inflammation, and fasting incretin change.

Validation of the Snouda Metabolic Score for Phenotyping and Guiding Reversal in Type 2 Diabetes

This study tests a new tool called the Snouda Metabolic Score (SMS) that helps doctors identify the specific metabolic problems driving Type 2 Diabetes in each individual patient. Instead of treating all diabetic patients the same way, the SMS classifies patients into one of several metabolic phenotypes - patterns of dysfunction across five body systems: insulin resistance, chronic inflammation, hormonal disruption, gut microbiome imbalance, and mitochondrial dysfunction. Once classified, each participant follows a personalized 24-week lifestyle and nutritional protocol targeting their specific phenotype. The protocol includes dietary changes, structured exercise, targeted nutritional supplements, and optional intermittent fasting. Participants track their blood glucose daily and complete biomarker blood tests at the start and end of the study. The main goal is to determine whether the SMS tool accurately identifies metabolic phenotypes and whether phenotype-matched protocols produce better outcomes than standard approaches. The study measures changes in HbA1c, fasting insulin, C-peptide, inflammation markers, and whether participants achieve Type 2 Diabetes remission - defined as HbA1c below 6.5% without glucose-lowering medication. The study is conducted entirely online through the diabetesreversal.io platform. There are no clinic visits required. Participants must be adults aged 18 or older with a confirmed Type 2 Diabetes diagnosis and must not be pregnant or breastfeeding.

Plasma Trimethylamine N-oxide Elevation Induced by L-carnitine Supplementation and Insulin Resistance

The primary aims of the current study: * using L-carnitine supplementation modulate the level of plasma trimethylamine N-oxide to assess its effect on circulating cytokines related to diabetes and metabolic syndrome; * using simulated night-shift work intervention as a stress factor, explore the effect of circulating metabolites on insulin sensitivity The secondary aim is to evaluate the effect of carnitine supplementation on gut microbiome composition.

Determining Cell- and Spatially-distinct Skeletal Muscle Transcriptional Aberrations in Insulin Resistance

The purpose of this study is to find new signs or signals in muscle cells that can help us understand when the body isn't responding well to insulin (a condition called insulin resistance).

Prebiotic Inulin for Late-Reproductive Individuals

This study aims to evaluate the effects of 2 weeks of inulin supplementation in perimenopausal women with overweight or obesity. The primary questions this study seeks to answer are: 1. Does 2 weeks of inulin supplementation alter the gut and vaginal estrobolome compared with placebo? 2. Does 2 weeks of inulin supplementation affect cardiovascular health compared with placebo? 3. Does 2 weeks of inulin supplementation affect skeletal muscle health compared with placebo? Researchers will compare inulin with a placebo (a similar-looking supplement that does not contain inulin) to determine whether inulin influences gut and vaginal microbial function, cardiovascular health, and skeletal muscle health during the perimenopausal transition. Participants will: * Take either inulin or a placebo for 2 weeks, followed by a 2- to 4-week washout period, and then switch to the other supplement for an additional 2 weeks. * Attend 8 study visits over approximately 12 to 16 weeks for assessments and sample collection. * Complete weekly phone calls to monitor symptoms, supplement adherence, and dietary intake. * Wear a Fitbit device throughout the study to monitor physical activity.

Everolimus Aging Study

The objective of this project is to determine if mTORC1 inhibition by 24 weeks of daily (0.5 mg/day) or weekly (5 mg/week) everolimus can safely improve physiological and molecular hallmarks of aging in humans. Participants who are 55-80 years old and insulin resistant or prediabetic will be randomized to treatment and can expect to be on study for up to approximately 38 weeks. Participants aged 18-35 will not receive the intervention and can expect to be on study for up to approximately 8 weeks.

Efficacy of NOSHINtrial in Diabetic Patients

The goal of this \[Efficacy of a traditional anti-diabetic herbal drug with on glycemic, inflammatory, and oxidative stress parameters\] is \[investigate the level of HOMA-estimated insulin resistance as the primary outcome before and after 40 days in intervention and placebo groups\] in \[patients with type 2 diabetes\]. The secondary outcomes of this study are the assessment of oxidative stress, inflammation biomarkers, other glycemic indices, hematopoietic status and lipid profile between the two groups before and after the intervention. also The food frequency questionnaire (FFQ) and the physical activity questionnaire (FAQ) are used to evaluate the effect of potential confounding factors. This study has the code of ethics IR.KMU.REC.1402.291 from Kerman University of Medical Sciences and this drug has the number 12/14484 from Iran Food and Drug Administration (IFDA).

Diazoxide Suppression Test P&F Study

The goal of this study is to learn about how the hormone insulin controls blood sugar. The main question it aims to answer is about how much insulin the body actually needs to maintain a normal blood sugar level. People with obesity and high insulin levels will receive eight doses of diazoxide, a drug that suppresses the pancreas's production of insulin, and will have their fasting blood sugar and insulin levels checked daily while taking the drug.

Study of the Effect of Innate on the Inflammatory Response to Endotoxin

Background: \- Innate immunity is the process by which white blood cells and other parts of the immune system sense and respond to potential infections by causing an inflammation. Researchers are interested in studying how the body responds to certain environmental factors, and whether the body s response can contribute to chronic illnesses or diseases such as asthma and certain types of cancers. Objectives: \- To examine how specific genes and proteins in blood cells respond to environmental exposures. Eligibility: \- Healthy volunteers between 18 and 45 years of age. Design: * The study will involve one visit of 45 to 60 minutes. * Participants will be screened with a brief physical examination and finger stick to determine if they are eligible to donate blood for the study, and will complete a questionnaire about any medications or other drugs (e.g., cigarettes) they may be taking. * Participants will provide a blood sample for research purposes.

A Sensory Strategy to Cut Sugary Beverages in African/American and Latine Adolescents

The goal of this clinical trial is to test whether replacing sugary sodas with unsweetened, flavored sparkling waters can reduce added sugar intake and improve health in Black/African American and Latine adolescents with obesity who prefer sweet-tasting beverages. The main questions it aims to answer are: * Does replacing sugary sodas with water change liking for sugary drinks, and water? * Do shifts in liking for sweetness lead to improved diet quality and cardiometabolic health? Researchers will compare replacing sugary sodas with one of three alternative beverages: unsweetened sparkling water, plain water, and beverages with gradually reduced sugar to determine which strategy is most effective. Participants will: * Replace sugary sodas with study drinks for 4 weeks * Complete taste tests to measure their liking for and sensory experience of sweetness over 8-weeks * Provide dietary recalls, body measurements, and blood samples over 8-weeks

Effect of Tele-exercise on Cardiorespiratory Fitness in Paediatrics

The goal of this clinical trial is to learn if telemedicine exercise programme can improve the cardiorespiratory fitness (how well your body delivers oxygen to muscles and organs) and insulin resistance in Asian children with low cardiorespiratory fitness levels. The main questions it aims to answers are: * Does telemedicine exercise programme improve the number of 20-metre laps the participant is able to run? * Does telemedicine exercise programme improve the insulin sensitivity using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) formula? Researchers will compare the telemedicine exercise programme to current active lifestyle programme (e.g., daily step count monitoring) to see if telemedicine exercise programme is more effective in improving cardiorespiratory fitness. Participants will: * participate in weekly telemedicine exercise programme or adhere to current active lifestyle recommendations through daily step count reporting for 10 weeks * visit the clinic for pre- and post-programme cardiorespiratory fitness assessments and blood taking

A Comparison of Neuromuscular Recruitment in Trained and Untrained Adults

The objective of the study is to use neurological techniques to obtain quantitative measurements of nervous system control of skeletal muscle activity in adults aged 60-85 who are either long-term resistance exercisers or who are untrained.

Evaluation of Serum Preptin Levels in Patients With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age and is strongly associated with insulin resistance and metabolic dysfunction. Preptin is a pancreatic peptide co-secreted with insulin and has been implicated in glucose metabolism and insulin resistance. However, limited data exist regarding serum preptin levels in patients with PCOS. The aim of this study is to evaluate serum preptin levels in women diagnosed with PCOS and to investigate the relationship between preptin levels and insulin resistance parameters.

Interplay of Central and Peripheral Vascular Effects of Insulin in Obesity

Determine the impact of obesity with insulin resistance on the neurovascular response to brain insulin stimulation.

Small Extracellular Vesicles and Insulin Action

The goals of this research study are to: 1) understand why some people with obesity are protected from developing conditions such as type 2 diabetes and cardiovascular disease while others are more likely to develop obesity-related conditions; 2) assess the effect of small extracellular vesicles (sEVs also called exosomes), obtained from human participants, on metabolic function in cultured cells and in mice.

Effects of Exercise Sequence and Meal Sequence on Weight Management Among Children and Adolescents With Overweight or Obesity: The STEP Trial

The goal of this clinical trial is to learn how the order of exercise and the order of eating food affect weight management in overweight and obese children and adolescents. The main questions it aims to answer are whether doing aerobic or anaerobic exercise first changes weight loss results, and whether eating vegetables and proteins before carbohydrates improves health outcomes compared to a standard diet. Furthermore, the study asks how the exercise order and eating order work together to affect weight and health. Researchers will compare four different groups to see if these specific exercise and eating orders work better to treat obesity. Participants will stay at a closed weight loss camp for 28 days and do daily aerobic and anaerobic exercises in a randomly assigned order. They will eat meals in either a strict order, consuming vegetables and proteins first, or a standard order. Throughout the trial, participants will give blood, urine, stool, saliva, and sweat samples for lab tests, while also checking their body weight, body composition, and heart rate. Finally, they will answer surveys about their diet, physical activity, hunger, and tiredness.

Non-Invasive Hepatic and Metabolic Index Changes After Incretin Therapy in Overweight/Obesity

This single-center, retrospective observational cohort study evaluated early changes in non-invasive hepatic and metabolic indices (FIB-4, APRI, HSI, and the triglyceride-glucose \[TyG\] index) in adults with overweight or obesity who received once-weekly subcutaneous semaglutide or tirzepatide for metabolic risk reduction related to metabolic dysfunction-associated steatotic liver disease (MASLD). Baseline and follow-up (minimum 12 weeks) clinical, anthropometric, and laboratory data from 154 patients treated at a single tertiary-care center in Turkey were analyzed. The study assessed whether short-term incretin-based therapy was associated with changes in fibrosis-related indices (FIB-4, APRI) versus steatosis- and insulin resistance-related indices (HSI, TyG), and identified independent predictors of these changes using multivariable linear regression.