Renal Functional Reserve as Long-Term Predictor of Kidney Disease Progression in Children
Understanding Kidney Reserve in Children with Kidney Disease
Andrew Schwaderer, MD
Primary Investigator
Brief description of study
Normal kidney has the ability to increase its filtration rate in response to a stress such as a protein load. In chronic kidney disease, the existing kidney functional units(nephrons)may already be operating at their maximum operating capacity and may not have much reserve available to increase filtration in response to a stress. These individuals may have normal labs, blood pressure and filtration rate, but have a decreased reserve function to increase in response to stress. There are studies in adults that show that decrease renal reserve can be a predictor of disease progression but there are no studies in children to show that. We aim to prove that this is also true in the case of children.
Detailed description of study
The patients will be provided with instructions and will be asked to eat a low protein diet the night before and then NPO until the protein load in the clinic next day. In the clinic, the protein load must be an animal protein to optimally induce the kidney stress response. We will provide 70 mg per 1.73 m2 protein meal (max 70 mg). For a 1.73m2 individual this approximately would be ~McDonald’s quarter pounder with 3 patties (or a similar burger from Riley Kitchen or another place) or 875 ml of a 40gm/5000 ml protein shakes (beef protein based). The protein load will be prorated for body surface area. For up to the 1st 4-10 control patients, we will enroll them for 2 study visit, one where they will have a RFR measured with a protein shake or protein bar and the other where it will be measured with a beef burger or vice versa. If the results are comparable and the children in the initial control group prefer the protein shake or bar to the burger, we will convert to the protein shake entirely as it will be more amenable to dosing per body size. We will do two blood draws in total, one at arrival at the clinic and the other two and a half hours after the protein meal.
Eligibility of study
You may be eligible for this study if you meet the following criteria:
- Conditions: Chronic kidney disease, CKD, Nephrotic syndrome, Glomerular disease, Riley
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Age: 12 years - 17 years
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Gender: All
Inclusion criteria for patients:
- Children 12-17-year-old with biopsy diagnosed nephrotic syndrome, glomerular disease or other kidney disease.
Inclusion criteria for controls:
- No history of known kidney disease and a normal UA or urine dipstick. Controls will be recruited from healthy siblings of children seen in the Pediatric Nephrology Clinic or Riley hospital inpatient service.
Exclusion Criteria:
- Vegetarian or non-beef diet, eating disorder, CKD stage 4 or higher CKD, hyperphosphatemia, diabetes mellitus, pregnancy, ACE inhibitor or ARB started, or dose increase withing 3 months.
This study investigates how the kidney's ability to increase its filtration rate, known as renal functional reserve, acts as a predictor of kidney disease progression in children. The study focuses on children with chronic kidney disease, where the kidney units (nephrons) may not have much reserve to increase filtration in response to stress. While adult studies suggest that reduced renal reserve can indicate disease progression, this study aims to determine if the same is true for children.
Participants will be asked to eat a low-protein diet the night before their clinic visit, and then avoid food until they receive a protein load at the clinic. The protein load, which stresses the kidney, will be tailored to the child's body size and may include a burger or protein shake. Two blood samples will be taken: one upon arrival and another two and a half hours after the protein meal to measure kidney response.
- Who can participate: Children aged 12-17 years with diagnosed nephrotic syndrome, glomerular disease, or other kidney diseases can participate. Controls must be healthy siblings with no known kidney disease and normal urine tests.
- Study details: Participants will follow a low-protein diet before the visit and receive a protein load at the clinic. Blood samples will be taken to assess kidney response to the protein load.
- Study visits: The study requires 2 visits.
