This clinical trial will determine whether a daily-caloric restriction-based weight loss intervention can slow kidney growth in adults with autosomal dominant polycystic kidney disease who are overweight or obese. The study will also evaluate changes in abdominal fat by magnetic resonance imaging. Blood and fat samples will provide insight into biological changes that may contribute to any observed benefits of the intervention.
Autosomal dominant polycystic kidney disease (ADPKD) is characterized by development and continued growth of numerous fluid-filled renal cysts that ultimately result in renal failure. Similar to the general population, the prevalence of overweight and obesity have been rising in ADPKD patients, effecting about two-thirds of individuals. Adipocytes do not simply act as a fat reservoir, but are active endocrine organs that promote release of pro-inflammatory cytokines, and thus, may be a promising clinical target for ADPKD management. Mounting evidence also suggests that a metabolic defect exists in ADPKD, which likely contributes to cystic epithelial proliferation and subsequent cyst growth. Additionally, the investigators recently reported that overweight and obesity are strong independent predictors of more rapid kidney growth. Collectively, these data suggest that interventions to reduce abdominal adiposity may slow ADPKD progression. Initial results from the investigators' R03-funded pilot and feasibility study support that a 12-month daily caloric restriction (DCR)-based behavioral weight loss intervention in adults with ADPKD and overweight or obesity: 1) is feasible and acceptable; 2) slowed kidney growth (annual %∆ in height-adjusted TKV \[htTKV\]), which was highly correlated with weight loss; 3) reduced abdominal adiposity; and 4) altered pathways implicated in ADPKD progression and metabolism. These initial results suggest that a DCR-based behavioral weight loss intervention offers a promising strategy to slow ADPKD progression. However, the pilot and feasibility study was limited by a small sample size, relatively short duration, and lack of a control group. Thus, to translate these promising results of the pilot study towards clinical practice, the investigators are conducting a randomized, controlled clinical trial in a larger number of adults with ADPKD and overweight or obesity to directly compare the efficacy of a DCR-based behavioral weight loss intervention compared to control for slowing kidney growth (primary outcome) over a longer duration. Changes in abdominal adiposity will serve as a secondary outcome and effects of weight loss on circulating and adipose markers of biological pathways will provide mechanistic insight. In a subset of participants recruited for this clinical trial, we will measure change in kidney oxidative metabolism, insulin sensitivity, plasma metabolomics, and gut microbiota. These additional measures will aim to compare kidney oxidative metabolism, insulin sensitivity, plasma metabolome and gut microbiota at baseline and 2 years. In addition, the investigators aim to define the relations among changes in kidney oxidative metabolism, insulin sensitivity, plasma metabolome, gut microbiota, total kidney volume, and body weight over 2 years. Currently, it is unknown if weight loss via DCR modifies renal energy expenditure, substrate utilization, plasma metabolomics, or the gut microbiome.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
125
Weight loss based on daily caloric restriction and increased physical activity
Initial nutrition consultation without subsequent counseling
University of Colorado - Anschutz Medical Campus
Aurora, Colorado, United States
Change in height-Adjusted Total kidney volume
To assess kidney growth, we will measure height-adjusted total kidney volume by magnetic resonance imaging at baseline and 24 months to determine annual percent change.
Time frame: Baseline, 24-months
Change in abdominal adiposity
Abdominal adiposity (subcutaneous, visceral, and total) will be assessed by magnetic resonance imaging.
Time frame: Baseline, 24-months
Change in the ratio of insulin-like growth factor-1 (IGF-1)/ to GF binding protein-1
Venous blood samples will be analyzed for this mechanistic biomarker
Time frame: Baseline, 12-months, 24-months
Change in adiponectin (circulating)
Venous blood samples will be analyzed for this mechanistic biomarker
Time frame: Baseline, 12-months, 24-months
Change in leptin (circulating)
Venous blood samples will be analyzed for this mechanistic biomarker
Time frame: Baseline, 12-months, 24-months
Change in interleukin-6 (circulating)
Venous blood samples will be analyzed for this mechanistic biomarker
Time frame: Baseline, 12-months, 24-months
Change in tumor necrosis factor-alpha (circulating)
Venous blood samples will be analyzed for this mechanistic biomarker
Time frame: Baseline, 12-months, 24-months
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Change in C-reactive protein (circulating)
Venous blood samples will be analyzed for this mechanistic biomarker
Time frame: Baseline, 12-months, 24-months
Change in peripheral blood mononuclear cell protein expression of pAMPK/AMPK
PBMCs will be isolated from whole blood to assess protein expression
Time frame: Baseline, 12-months, 24-months
Change in peripheral blood mononuclear cell protein expression of pS6K/S6K
PBMCs will be isolated from whole blood to assess protein expression
Time frame: Baseline, 12-months, 24-months
Change in adiponectin (adipose tissue)
A subcutaneous adipose tissue biopsy will be performed for assessment of this mechanistic biomarker.
Time frame: Baseline, 24-months
Change in leptin (adipose tissue)
A subcutaneous adipose tissue biopsy will be performed for assessment of this mechanistic biomarker.
Time frame: Baseline, 24-months
Change in interleukin-6 (adipose tissue)
A subcutaneous adipose tissue biopsy will be performed for assessment of this mechanistic biomarker.
Time frame: Baseline, 24-months
Change in tumor necrosis factor-alpha (adipose tissue)
A subcutaneous adipose tissue biopsy will be performed for assessment of this mechanistic biomarker.
Time frame: Baseline, 24-months
Change in renal oxygen consumption
Renal oxygen consumption will be assessed by a PET/CT scan using 11-C acetate in a sub-set of participants
Time frame: Baseline, 24-months
Change in gut microbiota
16S rRNA gene sequencing will be used for taxonomic characterization of the gut microbiota in a subset of participants.
Time frame: Baseline, 24-months
Change in plasma metabolome
Untargeted plasma metabolomics will be performed using high-performance liquid chromatography-tandem mass spectrometry in a subset of participants.
Time frame: Baseline, 24-months