Canagliflozin is an oral drug which is currently approved for use in patients with type 2 diabetes by the US Food and Drug Administration (FDA). Canagliflozin acts by increasing salt and sugar loss in the urine, and has shown to protect heart, kidney, and blood vessel function in patients with type 2 diabetes. However, it is unknown how canagliflozin protects the kidneys from disease. Therefore, this study plans to learn more about how canagliflozin works to protect against diabetic kidney disease in adults with type 2 diabetes. This study will use state-of-the-art kidney imaging, kidney biopsies and detailed testing of kidney function to determine the mechanisms of protection afforded by canagliflozin.
The purpose of this protocol is to examine the effects of the sodium-glucose cotransporter 2 (SGLT2) inhibitor canagliflozin on intrarenal transcripts of energy metabolism in adults with type 2 diabetes and early diabetic kidney disease (DKD) via an open-label non-randomized mechanistic trial. This trial will enroll 40 participants who will receive 100 mg of canagliflozin daily for six (6) months in addition to standard of care. The primary objective of this study is to determine whether canagliflozin affects intrarenal transcripts of energy metabolism in adults with type 2 diabetes and early DKD. The primary outcomes measure will be change in transcripts as assessed by single-cell RNA sequencing of kidney biopsy specimens obtained at study entry and after 6 months of study drug. Secondary outcomes include assessing the effects of canagliflozin on structural progression of DKD assessed by morphometric examination of kidney tissue specimens from the paired research biopsies. Additional secondary outcomes include measures of glomerular filtration rate (GFR) and renal plasma flow (RPF) as well as multiparametric kidney MRI. Magnetic resonance imaging of the kidneys will be performed prior to each biopsy to correlate the molecular and structural damage seen at kidney biopsy with the level of perfusion, oxygen availability and fibrosis detected by imaging. Imaging of the kidneys will be done as near to the time of each kidney biopsy as possible. Participants will be followed annually after completion of the mechanistic clinical trial until death or development of end-stage kidney disease. Of note, participants will be offered the option of staying on the SGLT2 inhibitor free of charge until 18 months after the last study biopsy or 24 months after enrollment to obtain the long-term impact of SGLT2 on GFR and proteinuria.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
45
Canagliflozin is in a class of medications called sodium-glucose co-transporter 2 (SGLT2) inhibitors. It is a used to treat type 2 diabetes. Canagliflozin lowers blood sugars by causing the kidneys to excrete more glucose in the urine.
Diagnostic aid/agent used to measure renal plasma flow (RPF) PAH (Basic Pharma, Geleen, Netherlands) has been used to measure RPF in human research for 7 decades, and is very well tolerated and generally recognized as safe with low toxicity.
University of Colorado Denver
Aurora, Colorado, United States
University of Michigan
Ann Arbor, Michigan, United States
Glomerular basement membrane (GBM) width and mesangial expansion
measured by morphometric examination of kidney tissue
Time frame: 6 months
Kidney Transcript Changes
Molecular changes measured by change in transcripts as assessed by single-cell RNA sequencing of kidney biopsy specimens
Time frame: 6 months
Cortical R2
Measured by Blood Oxygen Level Dependent (BOLD) MRI; Participants will be scanned in a supine position with a 3T MRI scanner. Spine array and body array receiver coils will be used to maximize image uniformity. Following initial localizer scans, coronal Sec T2-weighted MR images will be obtained to delineate cortical kidney regions. The image acquisition will be respiratory-gated to ensure accurate image co-registration with the respiratory-gated diffusion acquisitions.
Time frame: 6 months
Medullary R2
Measured by Blood Oxygen Level Dependent (BOLD) MRI; Participants will be scanned in a supine position with a 3T MRI scanner. Spine array and body array receiver coils will be used to maximize image uniformity. Following initial localizer scans, coronal Sec T2-weighted MR images will be obtained to delineate medullary kidney regions. The image acquisition will be respiratory-gated to ensure accurate image co-registration with the respiratory-gated diffusion acquisitions.
Time frame: 6 months
Renal Perfusion
Measured by Arterial Spin Labeling (ASL)
Time frame: 6 months
Glomerular Filtration Rate (GFR)
Measured by iohexol clearance; An intravenous (IV) line will be placed, and participants will be asked to empty their bladders. Spot plasma and urine samples will be collected prior to iohexol infusion. Iohexol will be administered through bolus IV injection (36 mg/kg/dose), followed by infusion (15mg/min over 180 min.) An equilibration period of 120 min was used and blood collections for iohexol plasma disappearance were drawn at +120, +150, +180 min.
Time frame: 3 Hours
Renal Plasma Flow (RPF)
Measured by para-aminohippurate (PAH) clearance; An intravenous (IV) line will be placed, and participants will be asked to empty their bladders. Spot plasma and urine samples will be collected prior to PAH infusion. PAH (2 g/10 mL, prepared by Basic Pharma, with a dose of (16 mg/kg or 12 mg/kg depending on eGFR) will be given slowly over 5 min followed by a continuous infusion of 8 mL of PAH and 42 mL of normal saline at a rate or 7.2 mg/kg/ hr or 5.0 mg/kg/hr for 2 h, depending on eGFR. After an equilibration period, blood will be drawn at 90, 120, and 150 min, and RPF will be calculated as PAH clearance divided by the estimated extraction ratio of PAH, which varies by the level of GFR.
Time frame: 2.5 Hours
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