Abstract
Background: The application of non-invasive proton magnetic resonance
spectroscopy (1H-MRS) could potentially identify changes in cerebral
metabolites in the patients with Alzheimer’s disease (AD). However, whether these
metabolites can serve as biomarkers for the diagnosis of AD remains unclear.
Objective: Using meta-analysis, we aimed to investigate the patterns of
cerebral metabolite changes in several cerebral regions that are strongly associated with
cognitive decline in AD patients.
Methods: Using Hedges’ g effect size, a systematic search was performed in
PubMed, Cochrane Library, Ovid, Embase, and EBSCO, and 38 studies were integrated into the
final meta-analysis.
Results: According to the observational studies, N-acetyl aspartate (NAA) in
AD patients was significantly reduced in the posterior cingulate (PC) (effect size
(ES) =−0.924, p < 0.005) and bilateral hippocampus (left hippocampus:
ES =−1.329, p < 0.005; right hippocampus: ES =−1.287,
p < 0.005). NAA/Cr (creatine) ratio decreased markedly in the PC
(ES =−1.052, p < 0.005). Simultaneously, significant elevated
myo-inositol (mI)/Cr ratio was found not only in the PC but also in the parietal gray
matter. For lack of sufficient data, we failed to elucidate the efficacy of
pharmacological interventions with the metabolites changes.
Conclusion: The available data indicates that NAA, mI, and the NAA/Cr ratio
might be potential biomarkers of brain dysfunction in AD subjects. Choline (Cho)/Cr and
mI/NAA changes might also contribute toward the diagnostic process. Thus, large,
well-designed studies correlated with cerebral metabolism are needed to better estimate
the cerebral extent of alterations in brain metabolite levels in AD patients.
