GLP-1 Therapy: The Role of IL-6 Signaling and Adipose Tissue Remodeling in Metabolic Response

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04387201

Enrollment

Registered

2020-05-13

Start date

2020-05-15

Completion date

2023-10-06

Last updated

2024-12-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Glucose Intolerance, Overweight and Obesity, Drug Effect, Adiposity

Keywords

GLP-1, prediabetes, brown fat, adipose tissue, IL-6

Brief summary

This project investigates the anti-obesity mechanisms of glucagon-like peptide-1 (GLP-1) analogs, which are used in the treatment of human obesity and diabetes mellitus. The investigators will test if GLP-1 induces secretion of interleukin-6 (IL-6), a cytokine that may collaborate with GLP-1 analogs to induce the formation of brown fat, which has anti-diabetic properties. The results will guide future obesity and diabetes mellitus therapies.

Detailed description

Incretins, the analogs of glucagon-like peptide-1 (GLP-1), improve glucose control in type 2 diabetes mellitus and counteract obesity through mechanisms that are not completely understood. The investigators' preliminary data show that, in prediabetic human subjects and mice, GLP-1 analog therapy induces an increase in plasma interleukin-6 (IL-6), a cytokine activating signal transducer and activator of transcription 3 (STAT3) signaling, which induces brown (beige) adipocyte differentiation in adipose tissue (AT). The investigators discovered that plasma IL-6 induction occurs through GLP-1 receptor (GLP-1R) stimulation in leukocytes. Interestingly, studies in rodents indicate that GLP-1 / GLP-1R signaling also induces AT beiging. Based on these observations, the investigators hypothesize that incretins induce AT browning in part via transient IL-6 / IL-6 receptor (IL-6R) / STAT3 signaling. The primary objective is to further elucidate the role of IL-6 and GLP-1 signaling in mediating beneficial metabolic effects of incretin therapy. Studies will be paralleled in a human clinical trial, a human cell culture model, and a mouse diet-induced obesity model. GLP-1 analog therapy combined with an IL-6 blocking antibody will be used. Specific Aim 1 is to (A) investigate IL-6 induction / downstream STAT3 signaling and AT browning upon incretin therapy in prediabetic human subjects; and (B) validate mice as a model to study incretin-induced IL-6 signaling as a mediator of AT browning. Specific Aim 2 is to (A) investigate if GLP-1 analog effects on beige adipogenesis depend on IL-6 signaling in human adipocyte progenitors; and (B) investigate if GLP-1 analog effects on beige adipogenesis depend on IL-6 signaling in mice. It is expected that 1) GLP-1 analog signaling via GLP-1R induces IL-6 secretion by leukocytes, and 2) GLP-1 analog therapy induces adipose tissue browning via both direct GLP-1 / GLP-1R signaling and indirect incretin-induced IL-6 / IL-6R / STAT3 signaling. The results of this novel study will give critical insights on the anti-obesity mechanisms of GLP-1 analogs and serve as the basis for developing more targeted therapies for diabetes and obesity. Understanding the anti-diabetic IL-6 effects will also be important for interpreting the results of IL-6 blockade, a therapeutic approach for patients with diabetes and other inflammatory conditions, which may need to be re-considered.

Interventions

DRUGCyanocobalamin

Cyanocobalamin (vitamin B12) 1000 mcg subcutaneous weekly for 6 weeks.

DRUGDulaglutide

Dulaglutide 0.75 mg subcutaneous weekly for 2 weeks, followed by 1.5 mg subcutaneous weekly for 4 weeks

Study design

Allocation

NON_RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

BASIC_SCIENCE

Masking

NONE

Intervention model description

Crossover clinical trial

Eligibility

Sex/Gender

ALL

Age

18 Years to 50 Years

Healthy volunteers

Inclusion criteria

1. Men and women, ages 18-50 years 2. Diagnosis of Prediabetes - defined as either impaired fasting glucose (fasting glucose of 100-125 mg/dL), impaired glucose tolerance (2-hour postprandial blood glucose of 140-199 mg/dL after 75-gram oral glucose challenge), and/or a hemoglobin A1C ranging from 5.5% to 6.4%. 3. BMI ≤ 35 kg/m2 4. Women of childbearing age must agree to use an acceptable method of pregnancy prevention (barrier methods, abstinence, oral contraception, vaginal rings, long-acting reversible contraceptives, or surgical sterilization) for the duration of the study 5. Patients must have the following laboratory values: Hematocrit ≥ 33 vol%, estimated glomerular filtration rate ≥ 60 mL/min per 1.73 m2, AST (SGOT) \< 2.5 times ULN, ALT (SGPT) \< 2.5 times ULN, alkaline phosphatase \< 2.5 times ULN 6. If patients are receiving antihypertensive medications (other than beta blockers) and/or lipid-lowering medications, they must remain on stable doses for the duration of the study. 7. If patients are receiving NSAIDs or antioxidant vitamins, these must be discontinued one week prior to study initiation and cannot be restarted during the study. 8. If patient takes thyroid medications, these must be dosed to control hypo- or hyperthyroidism.

Exclusion criteria

1. History of Type 1 or Type 2 diabetes mellitus 2. Pregnant or breastfeeding women 3. Medications: Beta blockers, corticosteroids, monoamine oxidase inhibitors, diabetes medications (including incretin mimetics and thiazolidinediones), and/or immunosuppressive therapy over the last 2 months. 4. Uncontrolled hypo- or hyperthyroidism 5. Current tobacco use 6. Active malignancy 7. History of clinically significant cardiac, hepatic, or renal disease. 8. History of any serious hypersensitivity reaction to study medications, any other incretin mimetic, any other formulation of supplemental vitamin B12, and/or cobalt 9. Personal or family history of Leber hereditary optic nerve atrophy 10. Prisoners or subjects who are involuntarily incarcerated 11. Compulsorily detention for treatment of either a psychiatric or physical (e.g., infectious disease) illness 12. Prior history of pancreatitis, medullary thyroid cancer, or multiple endocrine neoplasia type 2 (MEN 2) 13. Serum vitamin B12 level above the upper limit of assay detection

Design outcomes

Primary

Measure	Time frame	Description
Cytokine Interleukin-6 (IL-6) Messenger Ribonucleic Acid (mRNA) Level (From Adipose Tissue)	6 weeks after start of each intervention	natural log transformed data is reported
Uncoupling Protein 1 (UCP1) Messenger Ribonucleic Acid (mRNA) Level (From Adipose Tissue)	6 weeks after start of each intervention	Uncoupling protein 1 (UCP1) is a marker of beige/brown fat. natural log transformed data is reported
Signal Transducer and Activator of Transcription 3 (STAT3) Band Intensity/Western Blot (From Adipose Tissue)	6 weeks after start of each intervention	signaling intermediary with interleukin-6

Secondary

Measure	Time frame	Description
Beta2-adrenoceptor (ADRB2) (From Adipose Tissue)	6 weeks after start of each intervention	marker of beige/brown fat
Beta3-adrenoceptor (ADRB3) (From Adipose Tissue)	6 weeks after start of each intervention	marker of beige/brown fat
Nuclear Factor Kappa B (NfKappaB) p65 Band Intensity/Western Blot (From Peripheral Blood Mononuclear Cells)	6 weeks after start of each intervention	signaling intermediary with interleukin-6
Interleukin-6 (IL-6) mRNA (From Peripheral Blood Mononuclear Cells)	6 weeks after start of each intervention	cytokine
IL-6 (From Peripheral Blood Mononuclear Cells)	6 weeks after start of each intervention	cytokine
Suppressor of Cytokine Signaling 3 (SOCS3) Band Intensity/Western Blot (From Peripheral Blood Mononuclear Cells)	6 weeks after start of each intervention	signaling intermediary with interleukin-6
Cytokine IL-6 Level (From Plasma)	6 weeks after start of each intervention	natural log transformed data is reported. The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Free Fatty Acids Level (From Plasma)	6 weeks after start of each intervention	Free fatty acids level is a marker for insulin resistance. natural log transformed data is reported The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Insulin Level (From Plasma)	6 weeks after start of each intervention	Insulin Level is a marker of insulin resistance. natural log transformed data is reported. The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
PR Domain Containing 16 (PRDM16) Messenger Ribonucleic Acid (mRNA) Level ((From Adipose Tissue)	6 weeks after start of each intervention	PR domain containing 16 (PRDM16) is a marker of beige/brown fat. natural log transformed data is reported.
Tumor Necrosis Factor - Alpha (From Plasma)	6 weeks after start of each intervention	natural log transformed data is reported. The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Interleukin-4 (From Plasma)	6 weeks after start of each intervention	cytokine
Interleukin-10 (From Plasma)	6 weeks after start of each intervention	cytokine
Interleukin-11 (From Plasma)	6 weeks after start of each intervention	cytokine
Interleukin-13 (From Plasma)	6 weeks after start of each intervention	cytokine
Glucagon-like Peptide-1 (From Plasma)	6 weeks after start of each intervention	The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)	6 weeks after start of each intervention	Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) is a marker of insulin resistance, calculated according to the formula: fasting insulin (mU/mL) x fasting glucose (mmol/L)/22.5 The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Fat Browning Measured as Standard Uptake Value (From Positron Emission Tomography - Computed Tomography (PET-CT) Reading)	6 weeks after start of each intervention	The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Oroboros Oxygen Consumption	6 weeks after start of each intervention	measure of oxygen consumption
Glucose Level (From Plasma)	6 weeks after start of each intervention	Glucose Level is a marker of insulin resistance. The Measure Type indicated as Mean actually refers to a Adjusted Mean. Mean was adjusted for meteorological season. The meteorological season (i.e., spring, summer, fall, and winter) was adjusted for in the multivariable analysis as a potential confounding factor, since imbalances in ambient temperature between study arms could affect the findings.
Nicotinamide Adenine Dinucleotide Dehydrogenase (Ubiquinone) Iron-sulfur protein3 (NDUFS3) (From Adipose Tissue)	6 weeks after start of each intervention	marker of beige/brown fat
Beta1-adrenoceptor (ADRB1) (From Adipose Tissue)	6 weeks after start of each intervention	marker of beige/brown fat

Countries

United States

Participant flow

Participants by arm

Arm	Count
Cyanocobalamin, Then Dulaglutide Participants first received Cyanocobalamin (vitamin B12) 1000 mcg subcutaneous weekly for 6 weeks. After a washout period of 3 weeks, they then received Dulaglutide 0.75 mg subcutaneous weekly for 2 weeks, followed by 1.5 mg subcutaneous weekly for 4 weeks Cyanocobalamin: Cyanocobalamin (vitamin B12) 1000 mcg subcutaneous weekly for 6 weeks. Dulaglutide: Dulaglutide 0.75 mg subcutaneous weekly for 2 weeks, followed by 1.5 mg subcutaneous weekly for 4 weeks	17
Dulaglutide, Then Cyanocobalamin Participants first received Dulaglutide 0.75 mg subcutaneous weekly for 2 weeks, followed by 1.5 mg subcutaneous weekly for 4 weeks. After a washout period of of 3 weeks, they then Cyanocobalamin (vitamin B12) 1000 mcg subcutaneous weekly for 6 weeks. Cyanocobalamin: Cyanocobalamin (vitamin B12) 1000 mcg subcutaneous weekly for 6 weeks. Dulaglutide: Dulaglutide 0.75 mg subcutaneous weekly for 2 weeks, followed by 1.5 mg subcutaneous weekly for 4 weeks	6
Total	23

Baseline characteristics

Characteristic	Dulaglutide, Then Cyanocobalamin	Total	Cyanocobalamin, Then Dulaglutide
Age, Continuous	39 years STANDARD_DEVIATION 5	39 years STANDARD_DEVIATION 6	40 years STANDARD_DEVIATION 7
alanine aminotransferase (ALT) Level	20 units per liter STANDARD_DEVIATION 10	22 units per liter STANDARD_DEVIATION 13	24 units per liter STANDARD_DEVIATION 14
aspartate aminotransferase (AST) Level	19 units per liter STANDARD_DEVIATION 5	21 units per liter STANDARD_DEVIATION 7	22 units per liter STANDARD_DEVIATION 8
Body Mass Index	31.4 kilograms per square meter STANDARD_DEVIATION 2.8	30.73 kilograms per square meter STANDARD_DEVIATION 3.26	30.5 kilograms per square meter STANDARD_DEVIATION 3.4
Creatinine Level	0.9 milligrams per deciliter STANDARD_DEVIATION 0.2	0.9 milligrams per deciliter STANDARD_DEVIATION 0.2	0.9 milligrams per deciliter STANDARD_DEVIATION 0.3
Diastolic Blood Pressure	75 millimeters of mercury STANDARD_DEVIATION 8	77 millimeters of mercury STANDARD_DEVIATION 6	79 millimeters of mercury STANDARD_DEVIATION 6
Fasting Glucose Level	96 milligrams per deciliter STANDARD_DEVIATION 14	94 milligrams per deciliter STANDARD_DEVIATION 15	94 milligrams per deciliter STANDARD_DEVIATION 16
Hemoglobin Level	13 grams per deciliter STANDARD_DEVIATION 2	13 grams per deciliter STANDARD_DEVIATION 2	14 grams per deciliter STANDARD_DEVIATION 2
high-density lipoprotein (HDL) Cholesterol Level	55 milligrams per deciliter STANDARD_DEVIATION 8	55 milligrams per deciliter STANDARD_DEVIATION 21	56 milligrams per deciliter STANDARD_DEVIATION 24
low-density lipoprotein (LDL) Cholesterol Level	122 milligrams per deciliter STANDARD_DEVIATION 28	113 milligrams per deciliter STANDARD_DEVIATION 33	111 milligrams per deciliter STANDARD_DEVIATION 35
percentage of glycosylated hemoglobin	5.7 percentage of glycosylated hemoglobin STANDARD_DEVIATION 0.1	5.5 percentage of glycosylated hemoglobin STANDARD_DEVIATION 0.2	5.5 percentage of glycosylated hemoglobin STANDARD_DEVIATION 0.3
Platelets Count	285 billion cells per liter STANDARD_DEVIATION 51	293 billion cells per liter STANDARD_DEVIATION 82	296 billion cells per liter STANDARD_DEVIATION 90
Race/Ethnicity, Customized Black	3 Participants	8 Participants	5 Participants
Race/Ethnicity, Customized Caucasian	1 Participants	2 Participants	1 Participants
Race/Ethnicity, Customized Hispanic	0 Participants	8 Participants	8 Participants
Race/Ethnicity, Customized Other	2 Participants	5 Participants	3 Participants
Region of Enrollment United States	6 participants	23 participants	17 participants
Sex: Female, Male Female	5 Participants	14 Participants	9 Participants
Sex: Female, Male Male	1 Participants	9 Participants	8 Participants
Systolic Blood Pressure	118 millimeters of mercury STANDARD_DEVIATION 11	123 millimeters of mercury STANDARD_DEVIATION 12	126 millimeters of mercury STANDARD_DEVIATION 13
thyroid-stimulating hormone (TSH) level	1.8 milli-international units per liter STANDARD_DEVIATION 0.7	1.8 milli-international units per liter STANDARD_DEVIATION 1.2	1.8 milli-international units per liter STANDARD_DEVIATION 1.4
Total Cholesterol Level	201 milligrams per deciliter STANDARD_DEVIATION 31	195 milligrams per deciliter STANDARD_DEVIATION 36	193 milligrams per deciliter STANDARD_DEVIATION 38
Triglycerides Level	124 milligrams per deciliter STANDARD_DEVIATION 86	132 milligrams per deciliter STANDARD_DEVIATION 91	135 milligrams per deciliter STANDARD_DEVIATION 93
Vitamin B12 Level	495 picograms per milliliter STANDARD_DEVIATION 255	496 picograms per milliliter STANDARD_DEVIATION 199	497 picograms per milliliter STANDARD_DEVIATION 178

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk
deaths Total, all-cause mortality	0 / 23	0 / 23
other Total, other adverse events	1 / 23	0 / 23
serious Total, serious adverse events	0 / 23	0 / 23