Overview

This study is to investigate how adipocyte (fat cell) function and fat distribution differ between individuals with normal-weight type 2 diabetes (NWD), those with overweight type 2 diabetes (OWD), and normal-weight controls without diabetes (NWC). The study will assess whether adipocyte-directed therapies, specifically pioglitazone and tirzepatide, can improve insulin resistance, adipocyte function, and fat distribution in individuals with NWD. By analyzing the biological mechanisms underlying adipocyte dysfunction, the study aims to provide insights into novel treatment strategies for improving metabolic health in normal-weight individuals with type 2 diabetes.

Eligibility

Inclusion Criteria:

Normal-Weight Diabetes (NWD) Group:

1. Age: 30 to 70 years old.
2. Diagnosis of Type 2 Diabetes (T2D): Based on a previous diagnosis or confirmed by laboratory testing at screening (A1c \> 5.7% or fasting glucose \> 100 mg/dL).
3. HbA1c Range: Between 5.7% and 8%, with a stable medication or lifestyle regimen for at least 3 months.
4. BMI: Between 19 and 24.9 kg/m².
5. Diabetes Medications: All diabetes medications are allowed, except insulin and pioglitazone. GLP-1 receptor agonists are permitted if the dose has been stable for 3 months.
6. Stable Body Weight: Body weight must have been stable (no more than 2 kg change) over the last 3 months.

Normal-Weight Control (NWC) Group:

1. Age: 30 to 70 years old.
2. No Diagnosis of Diabetes: Fasting plasma glucose \< 100 mg/dL and A1c \< 5.7%, with no history of glucose-lowering medications.
3. BMI: Between 19 and 24.9 kg/m².
4. Stable Body Weight: No more than 2 kg change over the past 3 months. -

Exclusion Criteria:

1. Pregnancy or Lactation: Women who are pregnant, planning to become pregnant, or breastfeeding are excluded due to potential risks to the fetus or infant.
2. Prior Use of Pioglitazone: Participants who have previously used pioglitazone are excluded to avoid confounding effects of prior drug exposure.
3. Unstable Body Weight: Individuals with a body weight change of more than 2 kg in the last 3 months are excluded to ensure stable metabolic conditions.
4. Liver or Kidney Disease: Participants with significant liver disease (ALT \> 3x upper limit of normal) or renal disease (creatinine \> 1.5 mg/dL) are excluded due to potential safety risks.
5. Congestive Heart Failure or Fluid Overload History: These conditions are exclusionary due to the risk of fluid retention with pioglitazone.
6. Uncontrolled Hypertension: Blood pressure \> 160/90 mmHg excludes participants due to increased cardiovascular risk.
7. Active Cancer: Individuals with a diagnosis of cancer in the past 3 years (except for skin cancer) are excluded.
8. Chronic Inflammatory Diseases: Excluded due to potential effects on metabolic measurements.
9. Use of Weight Loss Medications: Those currently taking weight loss medications are excluded to prevent confounding effects on body weight and metabolic function.
10. Bariatric Surgery or Liposuction History: Participants who have had weight-loss surgeries or liposuction are excluded due to alterations in fat tissue and metabolic profiles.
11. Insulin Use: Participants using insulin are excluded to focus on non-insulin-dependent diabetes.
12. Active Psychiatric Disease or Eating Disorders: Individuals with these conditions are excluded due to potential impacts on study compliance and data integrity.
13. Substance Abuse: Participants with a history of substance abuse are excluded for similar reasons.

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