Figure 2. Experimental schema for hematopoietic stem cell transplantation (HSCT), deuterated water labeling, in vivo cell kinetics measurements, and deuterium MRI (dMRI) labeling imaging approach.

(A) Overview of method for deuterium water labeling of DNA. (B) Pictorial representation of syngeneic (syn) and allogeneic (allo) HSCT, timeline for ²H₂O labeling and delabeling periods for cell kinetics studies, and ²H₂O labeling for subsequent dMRI imaging of transplant recipients. (C) ²H₂O levels achieved in total body water (TBW) in normal mice and syngeneic and allogeneic HSCT recipients following 14 and 21 days of ²H₂O labeling prior to dMRI imaging at day +14 and +28 after HSCT, respectively. Data for 9 independent experiments were pooled (n = 8 mice for normal, n = 15 mice for syngeneic cohort, n = 19 mice for allogeneic cohort). (D) Deuterium enrichment in deoxyadenosine (dA) measured as dA (M+1) via GC-MS/MS for liver CD4⁺ Tem subset in the 3 cohorts at day +14 (n = 3 for each cohort). For panels C and D, *P < 0.05, ***P < 0.001; Tukey’s test with 2-way ANOVA.