Table 1.
Postmortem and PET studies demonstrating the presence or absence of microglial activation using different microglial markers in brain regions of interest in patients with schizophrenia, bipolar disorder and affective disorders
| Study | Subjects | Methods | Brain regions | Results |
|---|---|---|---|---|
| Bayer et al. [53] | 14 SZ, | Histology, HLA-DR | HPC, PFC | Activation of HLA-DR ↑ |
| 8 AD | ||||
| 13 CTR, | ||||
| Radewicz et al. [54] | 8 chronic SZ, 10 CTR (area 9), 7 chronic SZ, 6 CTR (area 22) | Histology, HLA-DR | DLPFC (Brodmann`s area 9), STG (area 22), ACC (area 24) | Area 9 ↑, |
| Area 22 ↑ | ||||
| Wierzba-Bobrowicz et al. [55] | 9 SZ, 6 CTR | Histology, HLA-DR | Frontal and temporal cortices | HLA-DR ↑ |
| Steiner et al. [57] | 16 SZ | Histology, HLA-DR | DLPFC, ACC, MD | DLPFC ↔ |
| 16 CTR | ACC ↔ , MD ↔ , cerebral lateralization of amoeboid microglia in SZ ↓, ↑ ACC, ↑ MD in SZ, who committed suicide | |||
| Steiner et al. [52] | 16 SZ | Histology, HLA-DR | DLPFC, ACC, MD, HPC | Significant differences in microglial cell densities ↔ among the groups; significant increases ↑ in DLPFC, ACC and MD in patients, who committed suicide |
| 14 AD | ||||
| 10 CTR | ||||
| Doorduin et al. [19] | 7 SZ | Pet with 11C-(R)-PK1195 | Frontal, occipital, temporal, parietal lobes, basal ganglia, thalamus, HPC, midbrain, cerebellum, pons | Binding of 11C-(R)-PK1195 ↑ in the HPC in SZ |
| 8 CTR | ||||
| Busse et al. [59] | 17 SZ | Histology, CD3 + T-lymphocytes, CD20 + B-lymphocytes, HLA-DR + microglia | Posterior HPC | CD3 + , CD20 + ↑ in residual SZ versus paranoid SZ, HLA-DR ↑ in paranoid SZ versus residual SZ |
| 11 CTR | ||||
| Fillman et al. [58] | 37 SZ | Histology, HLA-DR | DLPFC | Density in the white matter ↑ in SZ, density in gray matter ↔ in SZ |
| 37 CTR | ||||
| Kenk et al. [188] | 16 SZ | PET with TSPO | Gray matter: striatum, HPC, PFC, DLPFC, TC, white matter: CC, CING, SLF, PLIC | Significant difference in neuroinflammation ↔ |
| 27 CTR | ||||
| Najjar and Pearlman [17] | 15 studies: 350 SZ, 49 BD, 37 MDD, 10 AD, 346 CTR | Systematic review, neuropathological and neuroimaging studies | Gray and white matter | Microglial activation in the white matter in SZ, |
| Busse et al. [175] | 12 AD (6 MDD, 6 BD) | Histology, microglial QUIN | HPC (CA1, CA2/3 areas) | QUIN ↓ in the right CA1 area in MDD and BD |
| Bloomfield et al. [45] | 14 ultra-high risk SZ | PET with TSPO | Total gray matter, volume, frontal and temporal lobe gray matter | Microglial activity ↑ in ultra-high risk SZ |
| 14 CTR | ||||
| Di Biase et al. [47] | 10 ultra-high risk SZ | PET with TSPO | Dorsal frontal, orbital frontal, medial temporal cortex, medial temporal cortex, ACC | Significant difference in TSPO expression ↔ , microglial activation ↔ |
| 18 patients recently diagnosed with SZ | ||||
| 15 chronic SZ | ||||
| 27 CTR | ||||
| Brisch et al. [104] | 18 SZ | Histology, HLA-DR | DR | Microglial reaction ↓ in nonsuicidal patients compared with suicidal patients and CTR |
| 15 MDD | ||||
| 12 BD | ||||
| 22 CTR | ||||
| Hafizi et al. [46] | 14 first-episode SZ | PET with TSPO | DLPFC, HPC, medial prefrontal and temporal cortices, total gray matter | Significant difference in TSPO expression ↔ , microglial activation ↔ |
| 20 CTR | ||||
| van Kesteren et al. [41] | 783SZ | Meta-analysis, histology, various microglial markers | TC, PFC, OC, diencephalon, basal ganglia, ACC | Significant increase in microglial cell density ↑ |
| 762 CTR | ||||
| Conen et al. [49] | 20 ROS | PET with TSPO | ACC, PFC, PC, putamen, thalamus, and brainstem | Microglial activation ↔ in ACC, PFC, PC, and brainstem; microglial activation ↓ in thalamus and brainstem in ROS and ES |
| 21 ES | ||||
| 21CTR | ||||
| Petrasch-Parwez et al. [44] | 17 SZ | Histology, Iba-1 | aMC | No significant differences in IBA1 microglial densities between SZ, BD, and controls. A lateralization towards the right anterior midcingulate cortex was obsevered in SZ, BD, not in controls |
| 13 BD | ||||
| 17 CTR |
Abbreviations: ACC anterior cingulate cortex, AD patients with affective disorders, aMC anterior midcingulate cortex, BD patients with bipolar disorder, CC corpus callosum, CING cingulum, CTR healthy control subjects, DAT patients with dementia of Alzheimer’s type, DLPFC dorsolateral prefrontal cortex, DR dorsal raphe nucleus, ES patients with established schizophrenia, HPC hippocampus, HLA-DR human leukocyte antigen, MD mediodorsal thalamus, MDD patients with major depressive disorder, OC occipital cortex, PC parietal cortex, PET positron emission tomography, PFC prefrontal cortex, PLIC posterior limb of the internal capsule, QUIN quinolinic acid, ROS patients with recent onset schizophrenia, SLF superior longitudinal fasciculus, TSPO translocator protein, TC temporal cortex
Arrows: ↑ increase, ↔ no alteration ↓ decrease