A Phase 1/2 interventional study of Aminohippurate Sodium Inj 20% and Iohexol Inj 300 mg/mL in Type 2 Diabetes Mellitus, Obesity and Bariatric Surgery Candidate, sponsored by University of Colorado, Denver. Completed at 1 site in United States. Open to participants aged 12 Years to 21 Years. Per ClinicalTrials.gov, last updated 2026-01-12.
Sponsored by University of Colorado, Denver · Phase 1/2, Interventional, and Diagnostic
Type 2 diabetes (T2D) in youth is increasing in prevalence in parallel with the obesity epidemic. In the US, almost half of patients with renal failure have DKD, and ≥80% have T2D. Compared to adult-onset T2D, youth with T2D have a more aggressive phenotype with greater insulin resistance (IR), more rapid β-cell decline and higher prevalence of diabetic kidney disease (DKD), arguing for separate and dedicated studies in youth-onset T2D. Early DKD is characterized by changes in intrarenal hemodynamic function, including increased renal plasma flow (RPF) and glomerular pressure with resultant hyperfiltration, is common in Y-T2D, and predicts progressive DKD. Studies evaluating the two currently approved medications for treating T2D in youth (metformin and insulin) have shown these medications are not able to improve β-cell function over time in the youth. However, recent evidence suggests that bariatric surgery in adults is associated with improvements in diabetes outcomes, and even T2D remission in many patients. Limited data in youth also supports the benefits of bariatric surgery, regarding weight loss, glycemic control in T2D, and cardio-renal health. While weight loss is important, the acute effect of bariatric surgery on factors such as insulin resistance likely includes weight loss-independent mechanisms. A better understanding of the effects of bariatric surgery on pancreatic function, intrarenal hemodynamics, renal O2 and cardiovascular function in youth with obesity with or without diabetes is critical to help define mechanisms of surgical benefits, to help identify potential novel future non-surgical approaches to prevent pancreatic failure, DKD and cardiovascular disease.
The investigators' overarching hypotheses are that: 1) Y-T2D is associated with IR, pancreatic dysfunction, intrarenal hemodynamic dysfunction, elevated renal O2 consumption and cardiovascular dysfunction which improve with bariatric surgery, 2) The early effect of bariatric surgery on intrarenal hemodynamics is mediated by improvement in IR and weight loss, 3) Some aspects of cardio-renal-metabolic complications of T2D are related to obesity and others to T2D independent of obesity. To address these hypotheses, the investigators will measure GFR, RPF, glomerular pressure and renal O2, in addition to aortic stiffness, β-cell function and insulin sensitivity in youth ages 12-21 with T2D (n=40) and in (n=up to 10) youth with similar BMI but without diabetes, before and after vertical sleeve gastrectomy (VSG). To further investigate the mechanisms of renal damage in youth with T2D, two optional procedures are included in the study prior to vertical sleeve gastrectomy: 1) kidney biopsy procedure and 2) induction of induced pluripotent stem cells (iPSCs) to assess morphometrics and genetic expression of renal tissue.
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Exclusion Criteria:
Additional exclusion criteria for participants undergoing Visit 4 part 4, the optional kidney biopsy:
Participants will include youth who are scheduled for, and will undergo, vertical sleeve gastrectomy (VSG) surgery at the Bariatric Surgery Clinic at Children's Hospital of Colorado. To understand how bariatric surgery affects renal function, all participants will undergo assessment of Glomerular Filtration Rate, (Iohexol Inj 300 mg/mL) and Effective Renal Plasma Flow (Aminohippurate Sodium Inj 20%). In addition, participants will undergo imaging assessment that includes renal Blood Oxygen Level Dependent (BOLD) and Arterial Spin Labeling (ASL) MRI.
Drug: Aminohippurate Sodium Inj 20% · Drug: Iohexol Inj 300 mg/mL · Procedure: Vertical Sleeve Gastrectomy · Procedure: Renal Biopsy
Diagnostic aid/agent used to measure effective renal plasma flow (ERPF)
Also known as: Aminohippuric acid, Para-aminohippurate, Sodium 4-amino hippurate (PAH) inj 20% 2g/10 mL
Diagnostic aid/agent used to measure glomerular filtration rate (GFR)
Also known as: omnipaque 300
Participants will undergo vertical sleeve gastrectomy surgery, a laparoscopic bariatric surgery procedure designed for weight loss in obese patients
Also known as: Bariatric Surgery
Minimally invasive outpatient procedure in interventional radiology to obtain renal tissue cores.
Also known as: Kidney Biopsy
Pancreatic β-cell function
Measured by Mixed Meal Tolerance Test (MMTT)
Time frame: 4 hours (MMTT)
Pancreatic β-cell function
Measured by blood draws during/after hyperglycemic clamp
Time frame: 4 hours (hyperglycemic clamp)
Effective Renal Plasma Flow (ERPF)
Measured by PAH clearance
Time frame: 4 hours
Glomerular Filtration Rate (GFR)
Measured by iohexol clearance
Time frame: 4 hours
Renal Perfusion
Measured by Arterial Spin Labeling (ASL) MRI
Time frame: 10 min
Renal Oxygenation
Measured by Blood Oxygen Level Dependent (BOLD) MRI
Time frame: 60 min
Aortic Stiffness & Wall Shear Stress
Measured by Aortic MRI
Time frame: 30 min
Podocyte numerical density and number per glomerulus
Measured by light microscopy from tissue obtained by renal biopsy
Time frame: 4 hours
Foot process width of glomeruli
Measured from tissue obtained by renal biopsy
Time frame: 4 hours
Detachment and endothelial fenestration of glomeruli
Measured by electron microscopy from tissue obtained by renal biopsy
Time frame: 4 hours
Podocyte volume of glomeruli
Measured by electron microscopy from tissue obtained by renal biopsy
Time frame: 4 hours
Number and identity of RNA in kidney cells
Measured from tissue obtained by renal biopsy
Time frame: 4 hours
Epigenetic profiling
Measured from tissue obtained by renal biopsy
Time frame: 4 hours
Plan to share: Undecided
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University of Colorado, Denver