Collapsing glomerulopathy

Kidney Disease Biomarkers
Summary: This study will identify biomarkers (proteins and other molecules in the blood or urine) that may help scientists predict what kidney disease a patient has and whether a given patient would respond to particular therapies. The study will look for biomarkers in the blood and urine of patients with various kidney diseases and study of the effects of angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARB) on biomarkers. Blood and urine from healthy volunteers will be studied for comparison.
Healthy people and the following patients may be eligible for this study: adults with diabetic nephropathy 18 years of age and older; children with newly diagnosed clinical idiopathic nephrotic syndrome between 2 and 18 year of age; children and adults with glomerular disease (minimal change disease, focal segmental glomerulosclerosis, or collapsing glomerulopathy).
Participants undergo tests and procedures as follows:
Glomerular Disease: Adults with glomerular disease provide about four to six blood and urine samples over the course of 6 to 12 months. The samples are collected at the time of regularly scheduled visits for the NIH treatment protocol in which they are participating. Children provide only blood samples.
Chronic Kidney Disease: Patients with chronic kidney disease provide a blood and urine sample every 6 months for 3 years or more.
Angiotensin Antagonism: Patients with chronic kidney disease who are taking ACE inhibitors or ARBs stop their medicines for 4 weeks, while those who are not taking ACE inhibitors or ARBs begin one of the medicines. In general, patients just starting on the medications continue them after the study is completed, since they are beneficial for chronic kidney disease.
Medication withdrawal group: Patients come to NIH for 2 successive days at the beginning of the study for blood and urine tests (including one 24-hour urine collection) and to receive iothalamate (a chemical used to measure kidney function). Iothalamate is delivered over 24 hours through a needle placed in the abdomen (or elsewhere) via a pump similar to pumps that some diabetics use to deliver insulin. Patients then stop taking their ACE inhibitor or ARB medication. They monitor their blood pressure every day and return to NIH after 1, 2 and 4 weeks for blood tests. During week 4, the iothalamate infusion is repeated, and blood and urine samples are collected as at the beginning of the study. Patients then resume taking their ACE inhibitor or ARB once a day with the dose being increased at 2-week intervals. They come to NIH weekly after 1 week and then every other week for blood tests. Four weeks after reaching the highest FDA-recommended dose of medication tolerated, the iothalamate infusion and blood and urine collections are repeated.
Medication induction group: At the beginning of the study, patients have the iothalamate infusion and blood and urine collections described above and then begin to take either an ACE inhibitor or ARB. The dose is increased after 2 weeks. Patients monitor their blood pressure every day. After being on the highest dose for 4 weeks, patients repeat the iothalamate infusion and blood and urine collections. The study is then complete and they are provided a 2-month supply of medicine to take home.
Information is gathered on symptoms, treatments, and results of past laboratory tests of all patients. Healthy volunteers provide blood and urine sample collections every month or every other month for up to four collections to be used for biomarker studies and the screen for common chronic diseases.

This is a pilot study of retinoids for patients with unsatisfactory response to conventional treatment of nephrotic syndrome due to focal segmental glomerulosclerosis or minimal change disease, two renal disorders associated with putatively pathogenic malfunctioning of glomerular podocytes. The hypothesis that retinoids may have reparative effects on these cells is based on previous research showing that retinoids promote the differentiation or redifferentiation of aberrant epithelial cells. Results obtained by 6 months of treatment with retinoids (that have been approved for non-renal indications) will be used as preliminary information upon which to base further testing of these agents in formal clinical trials in refractory cases of these nephrotic syndromes.