QUANTITATIVE-ANALYSIS OF APOPTOTIC CELL-DEATH USING PROTON NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY

Quantification of apoptotic cell death in vivo has become an important area of investigation in patients with acute lymphoblastic leukemia ( ALL). We have devised a noninvasive analytical method to estimate the percentage of apoptotic lymphoblasts in doxorubicin-treated Jurkat T-c ell ALL cultures, using proton nuclear magnetic resonance spectroscopy (H-1 NMR). We have found that the ratio of the methylene (CH2) resona nce (at 1.3 ppm) to the methyl (CH3) resonance (at 0.9 ppm) signal int ensity, as observed by H-1 NMR, is directly proportional to the percen tage of apoptotic lymphoblasts in vitro. The correlation between the C H2/CH3 signal intensity ratio and the percentage of apoptotic lymphobl asts was optimal 24 to 28 hours after doxorubicin treatment (r(2) = .9 47, N = 27 samples), There was also a direct temporal relationship bet ween an increase in the CH2/ CH3 signal intensity ratio and the onset of apoptosis as detected by nuclear morphologic analysis, fluorescein- annexin V flow cytometry, and DNA gel electrophoresis. Thin-layer chro matography confirmed that a dynamic and/or compositional change of the plasma membrane, rather than increases in lipase activity or fatty ac id production, appears to account for the increase in the CH2/CH3 sign al intensity ratio during apoptosis. H-1 NMR may have clinical utility for the early noninvasive assessment of chemotherapeutic efficacy in patients with ALL. (C) 1997 by The American Society of Hematology.