Genetic of Skeletal Muscle Insulin Resistance

Identification of Cell Type-Specific Insulin Responsive Quantitative Trait Loci (QTL) in Human Skeletal Muscle

In this study, the investigators will use euglycemic/hyperinsulinemic clamps, longitudinal skeletal muscle biopsies, and single nucleus ribonucleic acid sequencing (RNA-Seq) and assay for transposase-accessible chromatin using sequencing (ATAC- seq) to reveal cell type-specific molecular response quantitative trait loci (rQTLs) acutely regulated by insulin signaling and glucose uptake.

The study investigators seek to find the relationship between basal and insulin stimulated Quantitative trait loci (QTL's) by utilizing vastus lateralis muscle biopsies before and after a euglycemic/hyperinsulinemic clamp. Each participant will have a catheter placed into an antecubital vein for the infusion of all test substances. A second catheter will be inserted retrogradely into a vein on the dorsum of the hand, and the hand will be placed into a thermoregulated box heated to 45 to 50 degrees Celsius. All participants will receive an infusion of [3-3H]glucose. After a 2-h basal tracer equilibration period, participants will receive a prime-continuous insulin infusion at the rate of 80mU/m2*min. During the last 30 min of the basal equilibration period and throughout the insulin infusion, plasma samples will be taken at 5-10 min intervals for the determination of plasma glucose and insulin concentrations and tritiated glucose radioactivity. During the insulin infusion, a variable in-fusion of 20% glucose will be adjusted, based on the negative feedback principle, to maintain the plasma glucose concentration at ~100mg/dL with a coefficient of variation <5%. Skeletal muscle biopsies will be obtained from the vastus lateralis muscle approximately 1h prior to and at the end of the insulin clamp, and will be snap frozen in liquid nitrogen for nuclei isolation.

Inclusion Criteria:

• Males and Females Age 18-75
• Body Mass Index (BMI) > 18
• Normal glucose tolerance as defined by:

Fasting blood sugar < 100 mg/dL 2-hour Oral Glucose Tolerance Test (OGTT) < 140mg/dL Stable weight over the past 3 months defined as >±5% change in body weight

• Hemoglobin A1c < 5.7
• Creatinine < 2
• Aspartate aminotransferase/Alanine transaminase (AST/ALT) < 75
• Blood sodium 135 to 145 mEq/L
• Blood potassium 3.6 to 5.2 mmol/L[MH1.1]

Exclusion Criteria:

• Urine albumin excretion>300mg/day
• Partial thromboplastin time (PTT) >35International normalized ratio (INR) > 1.2
• No oral corticosteroids for 1 month
• No Sodium-glucose co-transporter 2 (SGLT2) inhibitor for 3 months
• No glucagon-like peptide-1 (GLP-1) receptor agonist for 6 months
• Any anti-platelet or anti-coagulation medication other than as needed for Pain Management
• No alcohol 4 days before the insulin clamp and biopsy procedure
• No acute structural knee injuries
• No Rheumatologic muscular or nervous system disease
• Pregnancy, Intentions to become pregnant, or Breastfeeding
• Blood Pressure >170/110
• Temperature > 100F
• Triglycerides > 400 by lipid panel
• Hemoglobin <10g/dL
• 1+ or greater Blood on Urinalysis
• 2+ or greater Protein on Urinalysis
• Electrocardiogram (EKG) abnormalities, including but not limited to ST elevations, T wave abnormalities, evidence of recent prior infarct