Table 2.
Summary of included studies
| First author, publication year | Tissue | Analysis method | N (case/HC) | MMSE of case | Mean age | % Male |
|---|---|---|---|---|---|---|
| Brain GSH studies—AD | ||||||
| Mandal, 2015 [35] | Brain: hippocampus, frontal cortex | MEGA-PRESS, reference: water | 19/28 | 23.6 | 66.2 | 68% |
| Marjanska, 2019 [32] | Brain: posterior cingulate, occipital cortex | STEAM, reference: water | 16/33 | 19 | 73.2 | 82% |
| Mullins, 2018 [31] | Brain: posteromedial cortex | J-PRESS, reference: creatine | 27/54 | 25.4 | 72.2 | 57% |
| Shukla, 2019 | Brain: anterior and posterior cingulate | MEGA-PRESS, reference: water | 18/27 | N/A | 69.4 | 70% |
| Brain GSH studies—MCI | ||||||
| Duffy, 2014 [33] | Brain: anterior and posterior cingulate | PRESS, reference: creatine | 54/41 | 28.7 | 68 | 52% |
| Mandal, 2015 [35] | Brain: hippocampus, frontal cortex | MEGA-PRESS, reference: water | 22/28 | 24.2 | 66 | 65% |
| Oeltzschner, 2019 [34] | Brain: anterior and posterior cingulate | STEAM, reference: creatine | 13/26 | 28.1 | 69 | 65% |
| Shukla, 2019 | Brain: anterior and posterior cingulate | MEGA-PRESS, reference: water | 19/28 | N/A | 66.6 | 71% |
| Blood GSH studies—AD | ||||||
| Arslan, 2016 [36] | Erythrocyte | DTNB | 24/15 | N/A | 73.5 | 77% |
| Aybek, 2007 [37] | Serum | DTNB | 62/56 | 17.8 | 72.1 | 47% |
| Bai, 2018 [38] | Plasma | DTNB | 16/16 | 13.1 | N/A | N/A |
| Baldeiras, 2008 [39] | Plasma and erythrocyte | OPA | 42/37 | 20.9 | 70.8 | 39% |
| Bermejo, 2008 [40] | Erythrocyte | OPA | 45/28 | N/A | 80.0 | N/A |
| Bicikova, 2004 [41] | Serum | HPLC | 21/40 | N/A | 72.5 | 44% |
| Fernandes, 1999 [45] | Plasma and erythrocyte | OPA | 74/35 | N/A | 67.2 | 45% |
| Gironi, 2011 [43] | Serum | HPLC | 25/66 | 18.9 | 72.5 | 36% |
| Gironi, 2014 [42] | Erythrocyte | HPLC | 37/28 | N/A | 76.1 | 40% |
| Gubandru, 2013 [44] | Plasma | DTNB | 21/10 | 10.51 | 79.9 | 52% |
| Hernanz, 2007 [46] | Plasma | HPLC | 25/44 | N/A | 73.4 | 52% |
| Kliumiuk, 2019 [47] | Plasma | DTNB | 15/50 | 13.4 | 80.9 | 30% |
| Kosenko, 2016 [48] | Erythrocyte | DTNB | 12/14 | N/A | 76.1 | 35% |
| Krishnan, 2014 [49] | Plasma and erythrocyte | DTNB | 30/40 | 4 | 66.3 | 54% |
| Kurup, 2003 [50] | Erythrocyte | DTNB | 15/15 | N/A | N/A | N/A |
| Liu, 2005 [51] | Plasma,erythrocyte, and leukocyte | HPLC | 33/20 | 17.7 | 75.9 | 45% |
| Martinez de Toda, 2019 [52] | Whole blood | OPA | 20/30 | N/A | 55% | |
| McCaddon, 2003 [53] | Plasma | HPLC | 50/57 | 18 | 79.0 | 37% |
| Mohamed, 2019 [54] | Serum | ELISA | 50/25 | 19.2 | 69.8 | 50% |
| Prendecki, 2018 [55] | Plasma | HPLC | 88/80 | 15.3 | 73.9 | 73% |
| Puertas, 2012 [56] | Plasma | DTNB | 46/46 | 22 | 74.2 | 39% |
| Rani, 2017 [57] | Plasma | DTNB | 45/45 | 3.5 | 69.6 | N/A |
| Riveron, 2007 [58] | Plasma | DTNB | 25/30 | N/A | N/A | N/A |
| Sadhu, 2014 [59] | Plasma | DTNB | 104/93 | 6.4 | N/A | 54% |
| Tabet, 2002 [60] | Plasma | Commercial Assay Kit | 31/30 | 13.9 | N/A | 46% |
| Vida, 2018 [61] | Whole blood, neutrophil, lymphocyte | OPA | 44/38 | 19.3 | 75.9 | 41% |
| Blood GSH studies—MCI | ||||||
| Baldeiras, 2008 [39] | Plasma and erythrocyte | OPA | 85/37 | 27 | 70.3 | 39% |
| Bermejo, 2008 [40] | Erythrocyte | OPA | 34/28 | 27 | 78.3 | N/A |
| Gironi, 2011 [43] | Serum | HPLC | 20/66 | N/A | 71.4 | 33% |
| Gironi, 2014 [42] | Erythrocyte | HPLC | 26/28 | 21.5 | 76.5 | 43% |
| Hernanz, 2007 [46] | Plasma | HPLC | 26/44 | N/A | 74.4 | 51% |
| Martinez de Toda, 2019 [52] | Whole blood | OPA | 20/30 | 25 | N/A | 50% |
| Yuan, 2016 [62] | Plasma | Commercial assay kit | 138/138 | N/A | 64.5 | 51% |
Abbreviations: AD Alzheimer disease, DSM Diagnostic And Statistical Manual of Mental Disorders, DTBN 5,5′-dithio-bis(2-nitrobenzoic acid), ELISA enzyme-linked immunosorbent assay, GSH glutathione, HC healthy control, HPLC high performance liquid chromatography, MCI mild cognitive impairment, MEGA-PRESS Meshcher-Garwood Point-Resolved Spectroscopy, MMSE Mini-Mental State Examination, N/A not available, OPA O-Phthalaldehyde, PRESS Point-Resolved Spectroscopy, SMD standardized mean difference, STEAM STimulated Echo Acquisition Mode