Measurement of Renal Functional Reserve

Study Overview
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Brief Summary
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Single arm physiological study to measure renal functional reserve as a biomarker of kidney function and health

Detailed Description
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The investigators will measure glomerular filtration rate using urinary clearance of cold iothalamate before and after an oral protein load in patients with chronic kidney disease and healthy volunteers.

Official Title
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Measurement of Renal Functional Reserve With Urinary Clearance of Cold Iothalamate Before and After an Oral Protein Load

Conditions
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Kidney Diseases

Intervention / Treatment
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* Dietary Supplement: Ingestion of protein


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥18 Estimated GFR >30 mL/min/1.73m2 Exclusion Criteria: Allergy to iothalamate, shellfish or iodine Use of metformin or amiodarone Inability to maintain a stable regimen of medications which affect GFR for > one week prior to participation (e.g. non-steroidal anti-inflammatory drugs, angiotensin converting enzyme inhibitors, angiotensin receptor blockers) Use of medications which directly affect elimination of creatinine (e.g. cimetidine and trimethoprim) Acute exacerbation of asthma or chronic obstructive pulmonary disease within 3 months requiring hospitalization or oral steroid therapy Inadequate intravenous access Severe anemia (Hct <21%) Acute kidney injury (rise in creatinine to ≥1.5 times the previous baseline or by ≥ 0.3 mg/dL on most recent labs prior to enrollment) History of contrast-induced nephropathy Hyperthyroidism Pheochromocytoma Sickle cell disease Urinary retention or incontinence Status post organ transplant Pregnancy or active breast feeding Cognitive impairment with inability to give consent Institutionalized status

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: Physiological study to measure the change in glomerular filtration rate after an oral protein load
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study group<br>All study participants are in the same group and will have their kidney function measured twice, before and after ingestion of protein, 1 g/(kg body weight). The protein will be given in the form of the protein drink Liquacel (Global Health Products, Rochester, NY). | Dietary Supplement: Ingestion of protein<br>* Oral protein load as a physiological stimulus to temporarily increase glomerular filtration rate<br>* Other names: Liquacel (Global Health Products, Rochester, NY);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in glomerular filtration rate after ingestion of protein | Short term-changes in the glomerular filtration rate will be measured before and after ingestion of oral protein | Single full-day clinic visit: Repeated glomerular filtration rate measurements are to be performed over the course of the day at a single study visit for each participant. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Renal reserve, physiological study, diagnostic testing