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NCT Number: NCT07651397

Dietary Modulation of Urinary MCP-1 in ADPKD

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cyst growth and declining kidney function. Inflammatory pathways, including those mediated by monocyte chemoattractant protein-1 (MCP-1), are increasingly recognized as contributors to disease progression. Metabolic alterations in cystic epithelial cells may influence inflammatory signaling, suggesting a potential role for dietary interventions targeting metabolic pathways.

This study is a prospective, randomized, open-label crossover trial designed to evaluate the effect of a carbohydrate restricted, plant dominant dietary intervention on urinary MCP-1 levels in adults with ADPKD. Participants will be randomized to one of two sequences: dietary intervention followed by usual diet, or usual diet followed by dietary intervention, with a washout period between study phases. Each study period will last 12 weeks.

The primary objective is to assess within subject differences in urinary MCP-1/creatinine ratio between the dietary intervention and usual diet conditions. Secondary outcomes include measures of metabolic parameters, insulin resistance, dietary adherence, and safety.

This study aims to explore whether a structured dietary approach may influence intrarenal inflammatory activity in ADPKD and provide preliminary data to inform future interventional studies.

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Key information

Conditions

Autosomal Dominant Polycystic Kidney Disease (ADPKD) Abnormalities, Multiple Ciliopathies Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Genetic Diseases, Inborn Kidney Diseases Kidney Diseases, Cystic Male Urogenital Diseases Polycystic Kidney Diseases Polycystic Kidney, Autosomal Dominant Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥18
  • Diagnosis of ADPKD based on established clinical or genetic criteria (PKD 1/PKD2)
  • Estimated glomerular filtration rate (eGFR) between 45 and 90 mL/min/1.73 m²
  • Mayo Imaging Classification class 1C-1E based on MRI-derived height-adjusted total kidney volume.
  • Stable kidney function, defined as no acute kidney injury and no decline in eGFR >20% within the preceding 3 months
  • Stable antihypertensive and chronic medications for at least 4 weeks prior to enrollment
  • Ability and willingness to adhere to the prescribed dietary intervention
  • Ability to provide written informed consent

Exclusion criteria

  • eGFR <45 mL/min/1.73 m² or requirement for dialysis
  • History of kidney transplantation
  • Significant albuminuria, defined as urine albumin to creatinine ratio (UACR) >300 mg/g
  • Poorly controlled or unstable diabetes mellitus (e.g., HbA1c >8% or clinically significant glycemic variability or frequent hypoglycemia)
  • Use of Tolvaptan at the time of screening or within the study period
  • Current adherence to a ketogenic or carbohydrate restricted diet
  • Unintentional weight loss >5% within the preceding 3 months
  • Active infection, inflammatory disease, or malignancy that may influence inflammatory markers
  • Current use of systemic corticosteroids or immunosuppressive therapy
  • Active or symptomatic nephrolithiasis
  • Serum bicarbonate <20 mmol/L
  • Pregnancy or breastfeeding
  • Known eating disorder or condition limiting adherence to dietary interventions
  • Participation in another interventional study within the previous 3 months
  • Any condition that, in the opinion of the investigators, would interfere with study participation or interpretation of results

Treatment and study plan

Carbohydrate Restricted, Plant Dominant Diet

Behavioral

A structured dietary intervention targeting approximately 20% of total daily energy intake from carbohydrates (range 15-25%), with a plant dominant composition. Energy and protein intake are prescribed based on adjusted body weight. The intervention is not ketogenic and is not intended to induce nutritional ketosis. Participants receive individualized dietary counseling and ongoing support from a registered dietitian.

Usual diet

Behavioral

Participants continue their habitual diet without specific dietary intervention or structured nutritional guidance.

Primary outcomes

  1. Change in Urinary MCP-1/Creatinine Ratio

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Urinary MCP-1 levels will be measured in first morning urine samples and normalized to urine creatinine (MCP-1/creatinine ratio). For each study period, two samples will be collected within the final week (2-5 days apart), and the mean value will be used. The primary outcome is the within subject difference in MCP-1/creatinine ratio between the dietary intervention and usual diet conditions.

Secondary outcomes

  1. Association Between Carbohydrate Intake and MCP-1

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Mean carbohydrate intake during each study period will be calculated from repeated dietary assessments. The association between carbohydrate intake and urinary MCP-1/creatinine ratio will be evaluated to explore a potential dose response relationship.

  2. Association Between Change in HOMA-IR and MCP-1

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    The association between changes in insulin resistance (HOMA-IR) and changes in urinary MCP-1/creatinine ratio will be evaluated within individuals across study conditions.

  3. Dietary Adherence and MCP-1 Response

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Dietary adherence will be defined as the proportion of dietary assessments in which carbohydrate intake falls within the target range (15-25% of total energy intake). The association between adherence and urinary MCP-1/creatinine ratio will be evaluated.

  4. Change in Metabolic and Biochemical Parameters (Safety Outcomes)

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Changes in selected metabolic and biochemical parameters, including serum bicarbonate, LDL cholesterol, and estimated glomerular filtration rate (eGFR), will be assessed between study conditions to evaluate the safety of the dietary intervention.

Other outcomes

  1. Mediation Analysis of Insulin Resistance and MCP-1

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Exploratory analysis to evaluate whether changes in insulin resistance (HOMA-IR) mediate the relationship between dietary intervention and urinary MCP-1/creatinine ratio using regression based mediation models.

  2. Gene Expression of CPT1A and ACOX1

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Pre-specified exploratory analysis of gene expression of CPT1A and ACOX1, key regulators of fatty acid oxidation pathways, measured in peripheral blood samples. Expression levels will be evaluated in relation to dietary intervention and changes in urinary MCP-1/creatinine ratio.

  3. Exploratory Analysis of the Gut Microbiome

    Time frame: Baseline and End of each 12-week study period (weeks 0,12, 18 and 30)

    Exploratory analyses will evaluate changes in gut microbial composition associated with the dietary intervention. Stool samples collected at baseline and at the end of each study period will undergo microbiome analysis. Changes in microbial diversity and taxonomic composition will be explored and correlated with dietary adherence, urinary MCP-1 levels, and metabolic parameters. Given the exploratory nature of these analyses and the limited sample size, findings will be considered hypothesis-generating.

  4. Health-Related Quality of Life (SF-36)

    Time frame: Baseline and end of each 12-week study period (Weeks 0, 12, 18, and 30)

    Pre-specified exploratory assessment of health-related quality of life using the Short Form-36 (SF-36) questionnaire.

Study contacts

Contact information is provided by the study sponsor or research team.

ELAD NIZRI, MD

CONTACT

[email protected]

972-502932222

Sponsors and collaborators

Lead sponsor

Assaf-Harofeh Medical Center

Other Gov

Registry information

Official study title

Open Labeled , Randomized, Controlled, Crossover Trial on the Effect of a Carbohydrate Restricted Plant Dominant Diet on MCP-1 Mediated Inflammatory Signaling in Autosomal Dominant Polycystic Kidney Disease

Important dates

Study start
2026
Primary completion
2029
Study completion
2029
First posted
Jun 16, 2026
Registry last updated
Jun 26, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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