This is an interventional study to treat 18 patients with chronic kidney disease of unknown cause (CKDu), formerly known as Mesoamerican nephropathy (MeN), with autologous adipose tissue-derived stromal vascular fraction (SVF) cells transplanted by intra-arterial injection both kidneys.

This study assesses: (1) safety and tolerability, (2) preliminary evidence of efficacy, (3) exploratory evidence of clinical effects.

Patients under go 24 hours of preoperative hydration combined with N-actyl cysteine 300 mg IV for prevention of nephrotoxicity. Under general anesthesia 200-300 cc of lipoaspirate is collected into a sterile processing cannister (GID SFV-1, Louisville, CO, USA). The tissue is washed and dissociated with collagenase (Worthington CLS-1, Lakewood, NJ, USA) at a concentration of 200 CDU/ml of total volume for 50 minutes at 39°C. This is followed by inactivation using 40 cc of human serum albumin. SVF cells are separated via centrifugation for 10 minutes at 800 g. The cell pellet is extracted and resuspended in Harmann solution with an aliquot (10 µl) removed for counting and viability assessment of resulting total nucleated cells (YNC) through and image cytometer (ADAM MC, Portsmouth NH, USA).

Femoral artery catheterization is performed permitting advancement of a 100 cc balloon-tip catheter into the renal artery under fluoroscopic control, with position confirmation using 1 cc of OrtoRay® 320 contrast diluted 1:4 with Hartmann solution. SVF cells are then admixed with 200 cc Hartmann solution warmed to 37°C and in fused using a DRE infusion pump (DRE Medical, Louisville, KY, USA) over a 15 minute period with constant agitation. On the 1st pos-operative day creatinine and glomerular filtration rate are checked and the patient is discharged.

Follow-up studies include clinical assessment, chemistries, and renal ultrasound to assess intra-parenchymal renal volume, renal blood flow distribution, and hilar artery vascular resistance.

Inclusion Criteria:

• Diagnosis of Mesoamerican nephropathy
• Stages 3 and 4
• No other renal disease
• No essential hypertension

Exclusion Criteria:

• Significant abnormalities in laboratory tests that contraindicate surgical procedures.
• Acute pathology or complications of significant chronic pathologies in the 6 months prior to study entry, including, but not limited to:

Medical history of deep vein thrombosis Uncontrolled hypertension Active infection Reduced cardiac ejection fraction Hepatitis B, C or HIV Diabetes treated with insulin or glucose lowering agents Anemia (Hb <9 g/dL) History of cancer Severe depression (Beck scale) Autoimmune disease

• Open label for surgeons and radiologists
• Closed label for pathologists and nephrologists