Effects of abstinence from alcohol on the broad phospholipid signal in human brain: An in vivo P-31 magnetic resonance spectroscopy study

Background: In vivo phosphorus magnetic resonance spectroscopy (P-31 MRS) a t a magnetic field strength of 1.5 T allows measurement of fairly mobile me mbrane phospholipids in the human brain. We previously showed that subjects who are heavy drinkers had a smaller signal and a shorter transverse relax ation time (T-2) of white matter phospholipids than light drinkers, which s uggested lower concentrations and molecular mobility of phospholipids in he avy drinkers. The purpose of the present study was to measure if such chron ic alcohol-induced white matter tissue changes are persistent in long-term abstinent alcoholics. Methods: Fourteen abstinent alcoholics (mean age 45 years, seven men and se ven women) were studied by localized P-31 MRS in the centrum semiovale and were compared with 13 male, alcohol-dependent, heavy drinkers and 23 nondep endent light drinkers (17 men, 6 women) of similar age. Methods for measure ments of the broad membrane phospholipid signal and its relaxation time wer e described previously. Results: Phospholipid concentrations and relaxation times in alcoholics abs tinent for an average of 31 months were not significantly different from th ose measured in light drinkers. The contribution of fast and slowly relaxin g signal components to the broad phospholipid signal, however, was still di fferent in abstinent alcoholics compared with light drinkers. No effects of sex or of family history of alcoholism were noted on any of our spectrosco pic measures within the light-drinking or abstinent groups. Conclusions: Most of our results suggest at least partial recovery of chron ic alcohol-induced white matter phospholipid damage with long-term abstinen ce. They offer myelination changes and/or dendritic, rearborization as a po ssible mechanism for the commonly observed white matter volume gain with pr olonged abstinence. But the results also suggest a persistent abnormality i n the nature and/or physical properties of white matter phospholipids in lo ng-term abstinent alcoholics.