A PROTON MAGNETIC-RESONANCE SPECTROSCOPY STUDY OF AGING AND TRANSFORMED HUMAN FIBROBLASTS

Proton magnetic resonance spectroscopy (H-1 MRS) has been used to moni tor changes occurring during aging and transformation in human lung fi broblasts. Aging was studied in MRC-5 cells from nonsenescent (early p assage) to presenescent (late passage) and senescence. Nonsenescent ce lls infected with SV40 virus (pretransformed) were monitored through c risis and subsequent immortalization. Aging changes were observed with one- and two-dimensional MR spectra. Cholesterol and lipid resonances were significantly increased from nonsenescent cultures to senescence . These changes could be caused by chemical or structural changes in t he plasma membrane or in intracellular lipid pools. In contrast, choli ne levels rose from nonsenescent to presenescent cells but at senescen ce dropped to that of nonsenescent cells. Increased choline levels are often associated with increased cellular proliferation. After SV40 in fection of MRC-5 cells there was an increase of cholesterol and lipid levels that peaked at crisis. Newly immortalized cells exhibited a dro p in cholesterol and lipid to nonsenescent cell levels, but these rose again in established immortalized cells. In contrast to presensescent cultures, the levels of choline gradually increased from pretransform ed to crisis phase but still continued to rise after immortalization. Thus, H-1 MRS illustrates similarities in lipid behavior at senescence and crisis, whereas the choline levels are different. Copyright (C) 1 996 Elsevier Science Inc.