In vivo magnetic resonance spectroscopy of human fetal neural transplants

To better define the survival and cellular composition of human fetal neuro transplants in vivo, we performed quantitative H-1 MRS to determine the con centration of the neuronal amino acid [N-acetylaspartate] within MRI-visibl e grafts. In all, 71 grafts in 38 patients [24 Parkinson's disease (PD), 14 Huntington's disease (HD)] were examined, as well as 24 untreated PD and H D patients and 13 age-matched normal controls. MRI appearances of edema wer e present in three out of 71 grafts, the remainder being consistent with hi stologically identified viable neural transplant tissue. N-acetylaspartate (NAA), creatine, choline, myoinositol and glutamine plus glutamate (Glx) we re identified in all post-transplant putamens, with abnormal metabolites, l actate and/or lipid detectable in only three patients. Of 71 grafts, 19 occ upied more than 60% of the MRS-examined volume (VOI) (mean 84.2 +/- 3%; ran ge 61-100%). In those, [NAA] was 8.50 +/- 0.99 mM in eight PD spectra and 6 .59 +/- 0.81 mM in 11 HD spectra, and was not significantly different from controls. In contrast, transplanted fetal neurones contain less than 0.4 mM of the neuronal amino acid NAA. This suggests that established fetal neuro transplants in the human putamen of both PD and HD patients are populated b y adult neurones, axons and dendrites. Copyright (C) 1999 John Wiley & Sons , Ltd.