We read with great interest the prospective single-center study by Hiroomi Tatsumi et al., “Evaluation of Amino Acid Kinetics During Low-Dose Continuous Renal Replacement Therapy in Patients With Acute Kidney Injury.”1 The authors provide valuable quantitative data on amino-acid and protein losses during continuous veno-venous hemofiltration (CVVH) and relate these losses to the skeletal-muscle catabolism marker 3-methylhistidine. Their findings underscore the importance of aggressive nutritional support in acute kidney injury (AKI) patients receiving continuous renal replacement therapy (CRRT).