Inclusion Criteria:  Age 18-80 years Serum bicarbonate 16-24 mEq/L on 2 separate measurements (at least 1 day apart) Kidney transplant received 1 year prior to randomization eGFR ≥ 45 ml/min/1.73m2 by CKD-EPI equation Blood pressure <130/80 mm Hg prior to randomization BMI < 40 kg/m2 (FMD measurements can be inaccurate in severely obese patients). Able to provide consent Immunosuppression regimen consisting of tacrolimus, mycophenolate mofetil and prednisone (95% of patients at University of Colorado are on this regimen) Stable immunosuppression regimen for at least three months prior to randomization Stable anti-hypertensive regimen for at least one month prior to randomization Not taking medications that interact with agents administered during experimental sessions (e.g. sildenafil interacts with nitroglycerin).  Exclusion Criteria:  Significant comorbid conditions that lead the investigator to conclude that life expectancy is less than 1 year Use of chronic daily oral alkali within the last 3 months (including sodium bicarbonate, calcium carbonate or baking soda) Uncontrolled hypertension Serum potassium < 3.3 or ≥ 5.5 mEq/L at screening New York Heart Association Class 3 or 4 heart failure symptoms, known EF ≤30%, or hospital admission for heart failure within the past 3 months Nephrotic range proteinuria (urine complement activation fragment measurements may not be accurate with severe proteinuria) Factors judged to limit adherence to interventions Current participation in another research study Pregnancy or planning to become pregnant or currently breastfeeding Chronic use of supplemental oxygen Use of anticoagulants