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In vivo imaging of microglial activation with [11C](R)-PK11195 PET in idiopathic Parkinson's disease
Gerhard A, Pavese N, Hotton G, Turkheimer F, Es M, Hammers A, Eggert K, Oertel W et al.. Neurobiology of disease, 2005-09-21
Topic: Brain proteins, microglia and lab models
Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder associated with akinesia, tremor and rigidity. While the characteristic Lewy body pathology targets pigmented and other brainstem nuclei at post-mortem, activated microglia are found in both subcortical and cortical areas. [11C](R)-PK11195 is a positron emission tomography (PET) marker of peripheral benzodiazepine sites (PBBS), which are selectively expressed by activated microglia. We examined 18 PD patients clinically and with [11C](R)-PK11195 and [18F]-dopa PET. Compared to 11 normal controls, the PD patients showed significantly increased mean levels of [11C](R)-PK11195 binding in the pons, basal ganglia and frontal and temporal cortical regions. Eight PD patients were examined longitudinally, and their [11C](R)-PK11195 signal remained stable over 2 years. Levels of microglial activation did not correlate with clinical severity or putamen [18F]-dopa uptake. Our in vivo findings confirm that widespread microglial activation is associated with the pathological process in PD. The absence of significant longitudinal changes suggests that microglia are activated early in the disease process, and levels then remain relatively static, possibly driving the disease via cytokine release.
Key findings
- Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder associated with akinesia, tremor and rigidity.
- Compared to 11 normal controls, the PD patients showed significantly increased mean levels of [11C](R)-PK11195 binding in the pons, basal ganglia and frontal and temporal cortical regions.
- Our in vivo findings confirm that widespread microglial activation is associated with the pathological process in PD.
- The absence of significant longitudinal changes suggests that microglia are activated early in the disease process, and levels then remain relatively static, possibly driving the disease via cytokine release.
Why it matters
In 18 Parkinson's disease patients, PET imaging showed increased microglial activation in several brain regions compared with 11 controls, and this signal remained stable over 2 years in eight patients. The findings associate microglial activation with the disease process but did not test any treatment, and levels did not correlate with clinical severity.
Study details
- Study designlongitudinal study
- Evidence strengthModerate
How this study scored 62/100
Published in a peer-reviewed journal, and it is a longitudinal study following the same people over time. Scored zero for sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Neurobiology of disease) |
| Journal's citation record | 2 / 4 | Neurobiology of Disease: journal h-index 225 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2006 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 7 / 7 | Cited 1,199 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 54.5 citations a year over 22 year(s) since 2006 |
| Impact for its field and year | 4 / 6 | Cited 11.1× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 16 other studies in this library |
| Still being cited | 3 / 4 | Cited 186 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author David James Brooks: h-index 158 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | Imperial College London: institution h-index 1,744 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 4 institution(s) in 3 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 16182554) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 62 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1016/j.nbd.2005.08.002
- PubMed: 16182554
- Original source →
- Free full text: DOAJ (DOAJ: Directory of Open Access Journals) →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Gerhard, A., Pavese, N., Hotton, G., Turkheimer, F., Es, M., Hammers, A., et al. (2006). In vivo imaging of microglial activation with [11C](R)-PK11195 PET in idiopathic Parkinson's disease. Neurobiology of disease. https://doi.org/10.1016/j.nbd.2005.08.002
Vancouver
Gerhard A, Pavese N, Hotton G, Turkheimer F, Es M, Hammers A, et al. In vivo imaging of microglial activation with [11C](R)-PK11195 PET in idiopathic Parkinson's disease. Neurobiology of disease. 2006. doi:10.1016/j.nbd.2005.08.002. PMID: 16182554.
BibTeX
@article{gerhard2006-16182554,
author = {Gerhard, A. and Pavese, N. and Hotton, G. and Turkheimer, F. and Es, M. and Hammers, A. and Eggert, K. and Oertel, W. and others},
title = {{In vivo imaging of microglial activation with [11C](R)-PK11195 PET in idiopathic Parkinson's disease}},
journal = {Neurobiology of disease},
year = {2006},
doi = {10.1016/j.nbd.2005.08.002},
pmid = {16182554},
url = {https://doi.org/10.1016/j.nbd.2005.08.002}
}
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