Could your own cells heal kidneys after heart surgery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Male or female participants older than 18 years of age, being able to understand and sign the Informed Consent. 2. Participants undergoing elective valvular and/or coronary cardiac surgery performed with extracorporeal circulation. 3. Participants must meet one of the following two criteria: 1. Present pre-operative AKI risk more or equal to 30 percent according to the Leicester Cardiosurgery scale, in case the participants had signed the IC before. 2. Participants that had signed the IC within 12 hours after the AKI diagnosis. 4. Present AKI within the first 48 hours post cardiac surgery in one of the following classifications defined by the AKIN scale (Acute Kidney Injury Network): AKIN 1: An increase in serum creatinine by at least 0.3 mg/dL (more or equal to 26.4 micromol/L) from baseline, or an increase to more or equal to 150-200 percent (corresponding to a 1.5- to 2-fold increase) from baseline. In addition, the participant must have a positive acute tubular necrosis score within the first 48 hours post cardiac surgery, defined as the presence of at least 3 of the following 4 scenarios: Sodium excretion fraction more than 2 percent, urinary osmolality lower than 400 mOsm/kg, urine sodium more than 40 mmol/L, presence of shock or nephrotoxic agents. AKIN 2: An increase in serum creatinine to more than 200 percent and up to a maximum of 300 percent (corresponding to an increase of more than 2 and up to 3 times) over baseline. AKIN 3: An increase in serum creatinine to more than 300 percent (corresponding to more than 3-fold increase) over baseline, or an increase in serum creatinine levels to more or equal to 4.0 mg/dl (more or equal to 354 micromol/l) with an acute increase of at least 0.5 mg/dl (44 micromol/l). 5. In the case of women or men of childbearing age, for safety, those who undertake to follow the contraceptive measures required from their discharge from hospital until the end of their participation in the clinical trial. Exclusion Criteria: 1. Chronic Kidney Disease (CKD) in stage IV or V (glomerular filtration rate \[GFR\] less than 30 ml/min). 2. AKI one month prior to heart surgery. 3. Participants who have previously undergone renal replacement therapy. 4. Participants who, due to their clinical situation (hemodynamic instability, oliguria, current or anticipated volume overload) are scheduled to start renal replacement therapy within the next 48 hours after AKI diagnosis. 5. Interstitial glomerulonephritis or vasculitis. 6. Pregnancy. 7. Women in breastfeeding period 8. Renal transplant history. 9. Endocarditis. 10. Participants with mechanical assistance devices: extracorporeal membrane oxygenation (ECMO), left ventricular assist device (LVAD), right ventricular assist device (RVAD), intra-aortic balloon pumps (IABP). 11. Known severe ventricular dysfunction (left ventricular ejection fraction \[LVEF\] less than 30 percent). 12. Post-surgical septic infectious condition. 13. Clinically significant anemia with hemoglobin values below 100g/l. 14. Positive serology for hepatitis C virus (HCV), hepatitis B virus antigen (HBSAg), human immunodeficiency virus (HIV) or syphilis (by RPR: Rapid Plasma Reagin). This criterion will be assessed once it has been confirmed that the participant has developed AKI. 15. Participants enrolled in another clinical trial testing.