Imperial College London

Dr David R Owen MD PhD

Faculty of MedicineDepartment of Brain Sciences

Reader in Molecular Pharmacology and Experimental Medicine
 
 
 
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Contact

 

+44 (0)20 3313 6195d.owen Website

 
 
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Location

 

G20AICTEM buildingHammersmith Campus

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Summary

 

Publications

Publication Type
Year
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111 results found

Knowles S, Middleton R, Cooze B, Farkas I, Leung YY, Allen K, Winslade M, Owen DRJ, Magliozzi R, Reynolds R, Neal JW, Pearson O, Nicholas R, Pickrell WO, Howell OW, UK MS Register Research Groupet al., 2023, Comparing the pathology, clinical, and demographic characteristics of younger and older-onset multiple sclerosis, Annals of Neurology, ISSN: 0364-5134

OBJECTIVE: Older people with multiple sclerosis (MS) have a less active radiological and clinical presentation, but many still attain significant levels of disability; but what drives worsening disability in this group? METHODS: We used data from the UK MS Register to characterize demographics and clinical features of late-onset multiple sclerosis (LOMS; symptom onset at ≥50 years), compared with adult-onset MS (AOMS; onset 18-49 years). We performed a pathology study of a separate MS cohort with a later onset (n = 18, mean age of onset 54 years) versus AOMS (n = 23, mean age of onset 29 years). RESULTS: In the Register cohort, there were 1,608 (9.4%) with LOMS. When compared with AOMS, there was a lower proportion of women, a higher proportion of primary progressive MS, a higher level of disability at diagnosis (median MS impact scale 36.7 vs. 28.3, p < 0.001), and a higher proportion of gait-related initial symptoms. People with LOMS were less likely to receive a high efficacy disease-modifying treatment and attained substantial disability sooner. Controlling for age of death and sex, neuron density in the thalamus and pons decreased with onset-age, whereas actively demyelinating lesions and compartmentalized inflammation was greatest in AOMS. Only neuron density, and not demyelination or the extent of compartmentalized inflammation, correlated with disability outcomes in older-onset MS patients. INTERPRETATION: The more progressive nature of older-onset MS is associated with significant neurodegeneration, but infrequent inflammatory demyelination. These findings have implications for the assessment and treatment of MS in older people. ANN NEUROL 2023.

Journal article

Nutma E, Fancy N, Weinert M, Tsartsalis S, Marzin MC, Muirhead RCJ, Falk I, Breur M, de Bruin J, Hollaus D, Pieterman R, Anink J, Story D, Chandran S, Tang J, Trolese MC, Saito T, Saido TC, Wiltshire KH, Beltran-Lobo P, Phillips A, Antel J, Healy L, Dorion M-F, Galloway DA, Benoit RY, Amossé Q, Ceyzériat K, Badina AM, Kövari E, Bendotti C, Aronica E, Radulescu CI, Wong JH, Barron AM, Smith AM, Barnes SJ, Hampton DW, van der Valk P, Jacobson S, Howell OW, Baker D, Kipp M, Kaddatz H, Tournier BB, Millet P, Matthews PM, Moore CS, Amor S, Owen DRet al., 2023, Translocator protein is a marker of activated microglia in rodent models but not human neurodegenerative diseases, Nature Communications, Vol: 14, Pages: 1-25, ISSN: 2041-1723

Microglial activation plays central roles in neuroinflammatory and neurodegenerative diseases. Positron emission tomography (PET) targeting 18 kDa Translocator Protein (TSPO) is widely used for localising inflammation in vivo, but its quantitative interpretation remains uncertain. We show that TSPO expression increases in activated microglia in mouse brain disease models but does not change in a non-human primate disease model or in common neurodegenerative and neuroinflammatory human diseases. We describe genetic divergence in the TSPO gene promoter, consistent with the hypothesis that the increase in TSPO expression in activated myeloid cells depends on the transcription factor AP1 and is unique to a subset of rodent species within the Muroidea superfamily. Finally, we identify LCP2 and TFEC as potential markers of microglial activation in humans. These data emphasise that TSPO expression in human myeloid cells is related to different phenomena than in mice, and that TSPO-PET signals in humans reflect the density of inflammatory cells rather than activation state.

Journal article

Mahmud M, Wade C, Jawad S, Hadi Z, Otoul C, Kaminski RM, Muglia P, Kadiu I, Rabiner E, Maguire P, Johnson M, Owen Det al., 2023, Translocator protein PET imaging in temporal lobe epilepsy: a reliable test-retest study using laterality index, Frontiers in Neuroimaging, Vol: 2, Pages: 1-10, ISSN: 2813-1193

ObjectiveTranslocator-protein (TSPO) targeting positron emission tomography (PET) imaging radioligands have potential utility in epilepsy to assess the efficacy of novel therapeutics for targeting neuroinflammation. However, previous studies in healthy volunteers have indicated limited test-retest reliability of TSPO ligands. Here we examine test retest measures using TSPO PET imaging in subjects with epilepsy and healthy controls, to explore whether this biomarker can be used an endpoint in clinical trials for epilepsy.MethodsFive subjects with epilepsy and confirmed mesial temporal lobe sclerosis (mean age 36 years, 3 male) were scanned twice – on average 8 weeks apart – using a second generation TSPO targeting radioligand, [11C]PBR28. We evaluated the test-retest reliability of the volume of distribution and derived hemispheric asymmetry index of [11C]PBR28 binding in these subjects and compared the results with 8 (mean age 45, 6 male) previously studied healthy volunteers.ResultsThe mean (± SD) of the volume of distribution (VT), of all subjects, in patients living with epilepsy for both test and retest scans on all regions of interest is 4.49 ± 1.54, versus 5.89 ±1.23 in healthy volunteers. The bias between test and retest in asymmetry index as % was small (-1.5%) and reliability is demonstrated here with Bland-Altman Plots (test mean 1.062, retest mean 2.56). In subjects with epilepsy, VT of [11C]PBR28 is higher in the (ipsilateral) hippocampal region where sclerosis is present than in the contralateral region.ConclusionWhen using TSPO PET in epilepsy patients with hippocampal sclerosis, inter-hemispheric asymmetry index in the hippocampus is a measure with good test-retest reliability. We provide estimates of test-retest variability that may be useful for estimating power where group change in VT represents the clinic outcome.

Journal article

Writing Committee for the REMAP-CAP Investigators, Lawler PR, Derde LPG, van de Veerdonk FL, McVerry BJ, Huang DT, Berry LR, Lorenzi E, van Kimmenade R, Gommans F, Vaduganathan M, Leaf DE, Baron RM, Kim EY, Frankfurter C, Epelman S, Kwan Y, Grieve R, O'Neill S, Sadique Z, Puskarich M, Marshall JC, Higgins AM, Mouncey PR, Rowan KM, Al-Beidh F, Annane D, Arabi YM, Au C, Beane A, van Bentum-Puijk W, Bonten MJM, Bradbury CA, Brunkhorst FM, Burrell A, Buzgau A, Buxton M, Cecconi M, Cheng AC, Cove M, Detry MA, Estcourt LJ, Ezekowitz J, Fitzgerald M, Gattas D, Godoy LC, Goossens H, Haniffa R, Harrison DA, Hills T, Horvat CM, Ichihara N, Lamontagne F, Linstrum KM, McAuley DF, McGlothlin A, McGuinness SP, McQuilten Z, Murthy S, Nichol AD, Owen DRJ, Parke RL, Parker JC, Pollock KM, Reyes LF, Saito H, Santos MS, Saunders CT, Seymour CW, Shankar-Hari M, Singh V, Turgeon AF, Turner AM, Zarychanski R, Green C, Lewis RJ, Angus DC, Berry S, Gordon AC, McArthur CJ, Webb SAet al., 2023, Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support–free days in patients hospitalized with COVID-19, JAMA: Journal of the American Medical Association, Vol: 329, Pages: 1183-1196, ISSN: 0098-7484

IMPORTANCE: Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. OBJECTIVE: To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS: In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non-critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS: Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES: The primary outcome was organ support-free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS: On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support-free days among critically ill patients was 10 (-1 to 16) in the ACE inhibitor group (n = 231), 8 (-1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsen

Journal article

Roussakis A, Gennaro M, Gordon MF, Reilmann R, Borowsky B, Rynkowski G, Lao-Kaim NP, Papoutsou Z, Savola J-M, Hayden MR, Owen DR, Kalk N, Lingford-Hughes A, Gunn RN, Searle G, Tabrizi SJ, Piccini Pet al., 2023, A PET-CT study on neuroinflammation in Huntington’s patients participating in a randomised trial with laquinimod, Brain Communications, Vol: 5, Pages: 1-10, ISSN: 2632-1297

Microglia activation, an indicator of central nervous system inflammation, is believed to contribute to the pathology of Huntington’s disease. Laquinimod is capable of regulating microglia. By targeting the translocator protein, 11C-PBR28 PET-CT imaging can be used to assess the state of regional gliosis in vivo and explore the effects of laquinimod treatment. This study relates to the LEGATO-HD, multi-centre, double-blinded, Phase 2 clinical trial with laquinimod (US National Registration: NCT02215616). Fifteen patients of the UK LEGATO-HD cohort (mean age: 45.2 ± 7.4 years; disease duration: 5.6 ± 3.0 years) were treated with laquinimod (0.5 mg, N = 4; 1.0 mg, N = 6) or placebo (N = 5) daily. All participants had one 11C-PBR28 PET-CT and one brain MRI scan before laquinimod (or placebo) and at the end of treatment (12 months apart). PET imaging data were quantified to produce 11C-PBR28 distribution volume ratios. These ratios were calculated for the caudate and putamen using the reference Logan plot with the corpus callosum as the reference region. Partial volume effect corrections (Müller–Gartner algorithm) were applied. Differences were sought in Unified Huntington’s Disease Rating Scale scores and regional distribution volume ratios between baseline and follow-up and between the two treatment groups (laquinimod versus placebo). No significant change in 11C-PBR28 distribution volume ratios was found post treatment in the caudate and putamen for both those treated with laquinimod (N = 10) and those treated with placebo (N = 5). Over time, the patients treated with laquinimod did not show a significant clinical improvement. Data from the 11C-PBR28 PET-CT study indicate that laquinimod may not have affected regional translocator protein expression and clinical performance over the studied period.

Journal article

Robbins AJ, Che Bakri NA, Toke-Bjolgerud E, Edwards A, Vikraman A, Michalsky C, Fossler M, Lemm N-M, Medhipour S, Budd W, Gravani A, Hurley L, Kapil V, Jackson A, Lonsdale D, Latham V, Laffan M, Chapman N, Cooper N, Szydlo R, Boyle J, Pollock KM, Owen Det al., 2023, The effect of TRV027 on coagulation in COVID 19: A pilot randomized, placebo-controlled controlled trial, British Journal of Clinical Pharmacology, Vol: 89, Pages: 1495-1501, ISSN: 0306-5251

COVID-19 causes significant thrombosis and coagulopathy, with elevated D-dimer a predictor of adverse outcome. The precise mechanism of this coagulopathy remains unclear, one hypothesis is that loss of Angiotensin Converting Enzyme 2 activity during viral endocytosis leads to pro-inflammatory angiotensin II accumulation, loss of angiotensin-1-7 and subsequent vascular endothelial activation. We undertook a double blind randomised, placebo controlled experimental medicine study to assess the effect of TRV027, a synthetic angiotensin-1-7 analogue on D-dimer in 30 patients admitted to hospital with COVID-19 (REC ref. 20/HRA/3414), Clinical Trial No. NCT04419610.The study showed a similar rate of adverse events in TRV027 and control groups. There was a numerical decrease in D-dimer in the TRV027 group and increase in D-dimer in the placebo group, however, this did not reach statistical significance (p=0.15). A Bayesian analysis demonstrated there was a 92% probability that this change represented a true drug effect.

Journal article

Szubert AJ, Pollock KM, Cheeseman HM, Alagaratnam J, Bern H, Bird O, Boffito M, Byrne R, Cole T, Cosgrove CA, Faust SN, Fidler S, Galiza E, Hassanin H, Kalyan M, Libri V, McFarlane LR, Milinkovic A, O'Hara J, Owen DR, Owens D, Pacurar M, Rampling T, Skene S, Winston A, Woolley J, Yim YTN, Dunn DT, McCormack S, Shattock RJ, COVAC 1 Study Teamet al., 2023, COVAC1 phase 2a expanded safety and immunogenicity study of a self-amplifying RNA vaccine against SARS-CoV-2., EClinicalMedicine, Vol: 56, Pages: 1-13, ISSN: 2589-5370

BACKGROUND: Lipid nanoparticle (LNP) encapsulated self-amplifying RNA (saRNA) is well tolerated and immunogenic in SARS-CoV-2 seronegative and seropositive individuals aged 18-75. METHODS: A phase 2a expanded safety and immunogenicity study of a saRNA SARS-CoV-2 vaccine candidate LNP-nCoVsaRNA, was conducted at participating centres in the UK between 10th August 2020 and 30th July 2021. Participants received 1 μg then 10 μg of LNP-nCoVsaRNA, ∼14 weeks apart. Solicited adverse events (AEs) were collected for one week post-each vaccine, and unsolicited AEs throughout. Binding and neutralisating anti-SARS-CoV-2 antibody raised in participant sera was measured by means of an anti-Spike (S) IgG ELISA, and SARS-CoV-2 pseudoneutralisation assay. (The trial is registered: ISRCTN17072692, EudraCT 2020-001646-20). FINDINGS: 216 healthy individuals (median age 51 years) received 1.0 μg followed by 10.0 μg of the vaccine. 28/216 participants were either known to have previous SARS-CoV2 infection and/or were positive for anti-Spike (S) IgG at baseline. Reactogenicity was as expected based on the reactions following licensed COVID-19 vaccines, and there were no serious AEs related to vaccination. 80% of baseline SARS-CoV-2 naïve individuals (147/183) seroconverted two weeks post second immunization, irrespective of age (18-75); 56% (102/183) had detectable neutralising antibodies. Almost all (28/31) SARS-CoV-2 positive individuals had increased S IgG binding antibodies following their first 1.0 μg dose with a ≥0.5log10 increase in 71% (22/31). INTERPRETATION: Encapsulated saRNA was well tolerated and immunogenic in adults aged 18-75 years. Seroconversion rates in antigen naïve were higher than those reported in our dose-ranging study. Further work is required to determine if this difference is related to a longer dosing interval (14 vs. 4 weeks) or dosing with 1.0 μg followed by 10.0 μg. Boosting of S IgG an

Journal article

Coales I, Tsartsalis S, Nurun F, Weinert M, Clode D, Owen D, Matthews Pet al., 2022, Alzheimer’s disease related transcriptional sex differences in myeloid cells, Journal of Neuroinflammation, Vol: 19, ISSN: 1742-2094

Sex differences have been identified in many diseases associated with dysregulated immune responses, including Alzheimer’s disease (AD), for which approximately two-thirds of patients are women. An accumulating body of research indicates that microglia may play a causal role in the pathogenesis of this disease. We hypothesised that sex differences in the transcriptome of human myeloid cells may contribute to the sex difference observed in AD prevalence. To explore this, we assessed bulk and single-nuclear RNA sequencing data sets generated from four human derived myeloid cell populations: post-mortem microglial nuclei, peripheral monocytes, monocyte-derived macrophages (MDMs) and induced pluripotent stem cell derived microglial-like cells (MGLs). We found that expression of AD risk genes, gene signatures associated with the inflammatory response in AD, and genes related to proinflammatory immune responses were enriched in microglial nuclei isolated from aged female donors without ante-mortem neurological disease, relative to those from males. In addition, these inflammation-associated gene sets were found to be enriched in peripheral monocytes isolated from postmenopausal women and in MDMs obtained from premenopausal individuals relative to age-matched males. Expression of these gene sets did not differ in MDMs derived from women whose blood was sampled across the menstrual cycle or in MGLs cultured with 17β-oestradiol. This suggests that the observed gene set enrichments in myeloid cells from women were not being driven by acute hormonal influences. Together, these data support the hypothesis that the increased prevalence of AD in women may be partly explained by a myeloid cell phenotype biased towards expression of biological processes relevant to AD.

Journal article

Knowles S, Middleton R, Cooze B, Winslade M, Owen DJ, Reynolds R, Nicholas R, Pearson O, Pickrell WO, Howell Oet al., 2022, The demographics, clinical course and pathology of late-onset MS, 38th Congress of the European-Committee-for-Treatment-and-Research-in-Multiple-Sclerosis, Publisher: SAGE PUBLICATIONS LTD, Pages: 54-54, ISSN: 1352-4585

Conference paper

Cooze B, Farkas I, Leung Y, Yadanar H, Gerhards K, Gveric D, Nicholas R, Neal JW, Owen DR, Reynolds R, Howell OWet al., 2022, Neuronal loss in the thalamus and pons correlates with disease severity: Interim analysis of a large digital pathology study, 38th Congress of the European-Committee-for-Treatment-and-Research-in-Multiple-Sclerosis, Publisher: SAGE PUBLICATIONS LTD, Pages: 494-494, ISSN: 1352-4585

Conference paper

Owen D, 2022, Human pharmacokinetics of XBD173 and etifoxine distinguish their potential for pharmacodynamic effects mediated by TSPO, British Journal of Clinical Pharmacology, Vol: 88, Pages: 4230-4236, ISSN: 0306-5251

XBD173 and etifoxine are translocator protein (TSPO) ligands that modulate inflammatory responses in preclinical models. Limited human pharmacokinetic data is available for either molecule, and the binding affinity of etifoxine for human TSPO is unknown. To allow for design of human challenge experiments, we derived pharmacokinetic data for orally administered etifoxine (50 mg 3 times daily) and XBD173 (90 mg once daily) and determined the binding affinity of etifoxine for TSPO. For XBD173, maximum plasma concentration and free fraction measurements predicted a maximal free concentration of 1.0 nM, which is similar to XBD173 binding affinity. For etifoxine, maximum plasma concentration and free fraction measurements predicted a maximal free concentration of 0.31 nM, substantially lower than the Ki for etifoxine in human brain derived here (7.8 μM, 95% CI 4.5–14.6 μM). We conclude that oral XBD173 dosing at 90 mg once daily will achieve pharmacologically relevant TSPO occupancy. However, the occupancy is too low for TSPO mediated effects after oral dosing of etifoxine at 50 mg 3 times daily.

Journal article

Owen D, Phillips A, O'Connor D, Grey G, Aimola L, Nicholas R, Matthews Pet al., 2022, Human pharmacokinetics of XBD173 and etifoxine distinguish their potential for pharmacodynamic effects mediated by TSPO, British Journal of Clinical Pharmacology, ISSN: 0306-5251

<jats:p id="p1">XBD173 and etifoxine are TSPO ligands that modulate inflammatoryresponses in preclinical models. Limited human pharmacokinetic data isavailable for either molecule, and the binding affinity of etifoxine forhuman TSPO is unknown. To allow for design of human challengeexperiments, we derived pharmacokinetic data for orally administeredetifoxine (50mg TDS) and XBD173 (90mg OD) and determined the bindingaffinity of etifoxine for TSPO. For XBD173, Cmax and free fractionmeasurements predicted a maximal free concentration of 1.1 nM, which issimilar to XBD173 binding affinity. For etifoxine, Cmax and freefraction measurements predicted a maximal free concentration of 0.31 nM,substantially lower than the Ki for etifoxine in human brain derivedhere (7.8uM, 95% CI 4.5-14.6uM). We conclude that oral XBD173 dosing at90mg OD will achieve pharmacologically relevant TSPO occupancy. However,the occupancy is too low for TSPO mediated effects after oral dosing ofetifoxine at 50mg TDS.</jats:p>

Journal article

Pollock KM, Cheeseman HM, Szubert AJ, Libri V, Boffito M, Owen D, Bern H, O'Hara J, McFarlane LR, Lemm N-M, McKay PF, Rampling T, Yim YTN, Milinkovic A, Kingsley C, Cole T, Fagerbrink S, Aban M, Tanaka M, Mehdipour S, Robbins A, Budd W, Faust SN, Hassanin H, Cosgrove CA, Winston A, Fidler S, Dunn DT, McCormack S, Shattock RJ, COVAC1 study Groupet al., 2022, Safety and immunogenicity of a self-amplifying RNA vaccine against COVID-19: COVAC1, a phase I, dose-ranging trial, EClinicalMedicine, Vol: 44, ISSN: 2589-5370

Background: Lipid nanoparticle (LNP) encapsulated self-amplifying RNA (saRNA) is a novel technology formulated as a low dose vaccine against COVID-19. Methods: A phase I first-in-human dose-ranging trial of a saRNA COVID-19 vaccine candidate LNP-nCoVsaRNA, was conducted at Imperial Clinical Research Facility, and participating centres in London, UK, between 19th June to 28th October 2020. Participants received two intramuscular (IM) injections of LNP-nCoVsaRNA at six different dose levels, 0.1-10.0μg, given four weeks apart. An open-label dose escalation was followed by a dose evaluation. Solicited adverse events (AEs) were collected for one week from enrolment, with follow-up at regular intervals (1-8 weeks). The binding and neutralisation capacity of anti-SARS-CoV-2 antibody raised in participant sera was measured by means of an anti-Spike (S) IgG ELISA, immunoblot, SARS-CoV-2 pseudoneutralisation and wild type neutralisation assays. (The trial is registered: ISRCTN17072692, EudraCT 2020-001646-20). Findings: 192 healthy individuals with no history or serological evidence of COVID-19, aged 18-45 years were enrolled. The vaccine was well tolerated with no serious adverse events related to vaccination. Seroconversion at week six whether measured by ELISA or immunoblot was related to dose (both p<0.001), ranging from 8% (3/39; 0.1μg) to 61% (14/23; 10.0μg) in ELISA and 46% (18/39; 0.3μg) to 87% (20/23; 5.0μg and 10.0μg) in a post-hoc immunoblot assay. Geometric mean (GM) anti-S IgG concentrations ranged from 74 (95% CI, 45-119) at 0.1μg to 1023 (468-2236) ng/mL at 5.0μg (p<0.001) and was not higher at 10.0μg. Neutralisation of SARS-CoV-2 by participant sera was measurable in 15% (6/39; 0.1μg) to 48% (11/23; 5.0μg) depending on dose level received. Interpretation: Encapsulated saRNA is safe for clinical development, is immunogenic at low dose levels but failed to induce 100% seroconversion. Modifications to optimis

Journal article

Smith AM, Davey K, Tsartsalis S, Khozoie C, Fancy N, Tang SS, Liaptsi E, Weinert M, McGarry A, Muirhead RCJ, Gentleman S, Owen DR, Matthews PMet al., 2022, Diverse human astrocyte and microglial transcriptional responses to Alzheimer's pathology, ACTA NEUROPATHOLOGICA, Vol: 143, Pages: 75-91, ISSN: 0001-6322

Journal article

Amor S, Nutma E, Owen D, 2021, Imaging immune responses in neuroinflammatory diseases, CLINICAL AND EXPERIMENTAL IMMUNOLOGY, Vol: 206, Pages: 248-250, ISSN: 0009-9104

Journal article

Nutma E, Ceyzeriat K, Amor S, Tsartsalis S, Millet P, Owen DR, Papadopoulos V, Tournier BBet al., 2021, Cellular sources of TSPO expression in healthy and diseased brain, EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, Vol: 49, Pages: 146-163, ISSN: 1619-7070

Journal article

Nutma E, Gebro E, Marzin MC, van der Valk P, Matthews PM, Owen DR, Amor Set al., 2021, Activated microglia do not increase 18 kDa translocator protein (TSPO) expression in the multiple sclerosis brain, GLIA, Vol: 69, Pages: 2447-2458, ISSN: 0894-1491

To monitor innate immune responses in the CNS, the 18 kDa Translocator protein (TSPO) is a frequently used target for PET imaging. The frequent assumption that increased TSPO expression in the human CNS reflects pro-inflammatory activation of microglia has been extrapolated from rodent studies. However, TSPO expression does not increase in activated human microglia in vitro. Studies of multiple sclerosis (MS) lesions reveal that TSPO is not restricted to pro-inflammatory microglia/macrophages, but also present in homeostatic or reparative microglia. Here, we investigated quantitative relationships between TSPO expression and microglia/macrophage phenotypes in white matter and lesions of brains with MS pathology. In white matter from brains with no disease pathology, normal appearing white matter (NAWM), active MS lesions and chronic active lesion rims, over 95% of TSPO+ cells are microglia/macrophages. Homeostatic microglial markers in NAWM and control tissue are lost/reduced in active lesions and chronic active lesion rims, reflecting cell activation. Nevertheless, pixel analysis of TSPO+ cells (n = 12,225) revealed that TSPO expression per cell is no higher in active lesions and chronic active lesion rims (where myeloid cells are activated) relative to NAWM and control. This data suggests that whilst almost all the TSPO signal in active lesions, chronic active lesion rims, NAWM and control is associated with microglia/macrophages, their TSPO expression predominantly reflects cell density and not activation phenotype. This finding has implications for the interpretation of TSPO PET signal in MS and other CNS diseases, and further demonstrates the limitation of extrapolating TSPO biology from rodents to humans.

Journal article

Marques TR, Veronese M, Owen DR, Rabiner EA, Searle GE, Howes ODet al., 2021, Specific and non-specific binding of a tracer for the translocator-specific protein in schizophrenia: an [11C]-PBR28 blocking study, EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, Vol: 48, Pages: 3530-3539, ISSN: 1619-7070

Journal article

Ramakrishnan NK, Hird M, Thompson S, Williamson DJ, Qiao L, Owen DR, Brooks AF, Scott PJH, Bacallado S, O'Brien JT, Aigbirhio FIet al., 2021, Preclinical evaluation of (S)-[18F]GE387, a novel 18-kDa translocator protein (TSPO) PET radioligand with low binding sensitivity to human polymorphism rs6971, European Journal of Nuclear Medicine and Molecular Imaging, Vol: 49, Pages: 125-136, ISSN: 0340-6997

PURPOSE: Positron emission tomography (PET) studies with radioligands for 18-kDa translocator protein (TSPO) have been instrumental in increasing our understanding of the complex role neuroinflammation plays in disorders affecting the brain. However, (R)-[11C]PK11195, the first and most widely used TSPO radioligand has limitations, while the next-generation TSPO radioligands have suffered from high interindividual variability in binding due to a genetic polymorphism in the TSPO gene (rs6971). Herein, we present the biological evaluation of the two enantiomers of [18F]GE387, which we have previously shown to have low sensitivity to this polymorphism. METHODS: Dynamic PET scans were conducted in male Wistar rats and female rhesus macaques to investigate the in vivo behaviour of (S)-[18F]GE387 and (R)-[18F]GE387. The specific binding of (S)-[18F]GE387 to TSPO was investigated by pre-treatment with (R)-PK11195. (S)-[18F]GE387 was further evaluated in a rat model of lipopolysaccharide (LPS)-induced neuroinflammation. Sensitivity to polymorphism of (S)-GE387 was evaluated in genotyped human brain tissue. RESULTS: (S)-[18F]GE387 and (R)-[18F]GE387 entered the brain in both rats and rhesus macaques. (R)-PK11195 blocked the uptake of (S)-[18F]GE387 in healthy olfactory bulb and peripheral tissues constitutively expressing TSPO. A 2.7-fold higher uptake of (S)-[18F]GE387 was found in the inflamed striatum of LPS-treated rodents. In genotyped human brain tissue, (S)-GE387 was shown to bind similarly in low affinity binders (LABs) and high affinity binders (HABs) with a LAB to HAB ratio of 1.8. CONCLUSION: We established that (S)-[18F]GE387 has favourable kinetics in healthy rats and non-human primates and that it can distinguish inflamed from normal brain regions in the LPS model of neuroinflammation. Crucially, we have reconfirmed its low sensitivity to the TSPO polymorphism on genotyped human brain tissue. Based on these factors, we conclude that (S)-[18F]GE387 warrants furt

Journal article

Feleke R, Reynolds RH, Smith AM, Tilley B, Taliun SAG, Hardy J, Matthews PM, Gentleman S, Owen DR, Johnson MR, Srivastava PK, Ryten Met al., 2021, Cross-platform transcriptional profiling identifies common and distinct molecular pathologies in Lewy body diseases, Acta Neuropathologica, Vol: 142, Pages: 449-474, ISSN: 0001-6322

Parkinson's disease (PD), Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB) are three clinically, genetically and neuropathologically overlapping neurodegenerative diseases collectively known as the Lewy body diseases (LBDs). A variety of molecular mechanisms have been implicated in PD pathogenesis, but the mechanisms underlying PDD and DLB remain largely unknown, a knowledge gap that presents an impediment to the discovery of disease-modifying therapies. Transcriptomic profiling can contribute to addressing this gap, but remains limited in the LBDs. Here, we applied paired bulk-tissue and single-nucleus RNA-sequencing to anterior cingulate cortex samples derived from 28 individuals, including healthy controls, PD, PDD and DLB cases (n = 7 per group), to transcriptomically profile the LBDs. Using this approach, we (i) found transcriptional alterations in multiple cell types across the LBDs; (ii) discovered evidence for widespread dysregulation of RNA splicing, particularly in PDD and DLB; (iii) identified potential splicing factors, with links to other dementia-related neurodegenerative diseases, coordinating this dysregulation; and (iv) identified transcriptomic commonalities and distinctions between the LBDs that inform understanding of the relationships between these three clinical disorders. Together, these findings have important implications for the design of RNA-targeted therapies for these diseases and highlight a potential molecular "window" of therapeutic opportunity between the initial onset of PD and subsequent development of Lewy body dementia.

Journal article

Voysey M, Clemens SAC, Madhi SA, Weckx LY, Folegatti PM, Aley PK, Angus B, Baillie VL, Barnabas SL, Bhorat QE, Bibi S, Briner C, Cicconi P, Clutterbuck EA, Collins AM, Cutland CL, Darton TC, Dheda K, Dold C, Duncan CJA, Emary KRW, Ewer KJ, Flaxman A, Fairlie L, Faust SN, Feng S, Ferreira DM, Finn A, Galiza E, Goodman AL, Green CM, Green CA, Greenland M, Hill C, Hill HC, Hirsch I, Izu A, Jenkin D, Joe CCD, Kerridge S, Koen A, Kwatra G, Lazarus R, Libri V, Lillie PJ, Marchevsky NG, Marshall RP, Mendes AVA, Milan EP, Minassian AM, McGregor A, Mujadidi YF, Nana A, Padayachee SD, Phillips DJ, Pittella A, Plested E, Pollock KM, Ramasamy MN, Ritchie AJ, Robinson H, Schwarzbold AV, Smith A, Song R, Snape MD, Sprinz E, Sutherland RK, Thomson EC, Torok ME, Toshner M, Turner DPJ, Vekemans J, Villafana TL, White T, Williams CJ, Douglas AD, Hill AVS, Lambe T, Gilbert SC, Pollard AJet al., 2021, Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials, The Lancet, Vol: 397, Pages: 881-891, ISSN: 0140-6736

BackgroundThe ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, Medicines and Healthcare products Regulatory Agency, with a regimen of two standard doses given with an interval of 4–12 weeks. The planned roll-out in the UK will involve vaccinating people in high-risk categories with their first dose immediately, and delivering the second dose 12 weeks later. Here, we provide both a further prespecified pooled analysis of trials of ChAdOx1 nCoV-19 and exploratory analyses of the impact on immunogenicity and efficacy of extending the interval between priming and booster doses. In addition, we show the immunogenicity and protection afforded by the first dose, before a booster dose has been offered.MethodsWe present data from three single-blind randomised controlled trials—one phase 1/2 study in the UK (COV001), one phase 2/3 study in the UK (COV002), and a phase 3 study in Brazil (COV003)—and one double-blind phase 1/2 study in South Africa (COV005). As previously described, individuals 18 years and older were randomly assigned 1:1 to receive two standard doses of ChAdOx1 nCoV-19 (5 × 1010 viral particles) or a control vaccine or saline placebo. In the UK trial, a subset of participants received a lower dose (2·2 × 1010 viral particles) of the ChAdOx1 nCoV-19 for the first dose. The primary outcome was virologically confirmed symptomatic COVID-19 disease, defined as a nucleic acid amplification test (NAAT)-positive swab combined with at least one qualifying symptom (fever ≥37·8°C, cough, shortness of breath, or anosmia or ageusia) more than 14 days after the second dose. Secondary efficacy analyses included cases occuring at least 22 days after the first dose. Antibody responses measured by immunoassay and by pseudovirus neutralisation were exploratory outcomes. All cases of COVID-19 with a NAAT-positive swab were adjudicated for inclusion in the analysis by a masked

Journal article

Voysey M, Clemens SAC, Madhi SA, Weckx LY, Folegatti PM, Aley PK, Angus B, Baillie VL, Barnabas SL, Bhorat QE, Bibi S, Briner C, Cicconi P, Collins AM, Colin-Jones R, Cutland CL, Darton TC, Dheda K, Duncan CJA, Emary KRW, Ewer KJ, Fairlie L, Faust SN, Feng S, Ferreira DM, Finn A, Goodman AL, Green CM, Green CA, Heath PT, Hill C, Hill H, Hirsch I, Hodgson SHC, Izu A, Jackson S, Jenkin D, Joe CCD, Kerridge S, Koen A, Kwatra G, Lazarus R, Lawrie AM, Lelliott A, Libri V, Lillie PJ, Mallory R, Mendes AVA, Milan EP, Minassian AM, McGregor A, Morrison H, Mujadidi YF, Nana A, O'Reilly PJ, Padayachee SD, Pittella A, Plested E, Pollock KM, Ramasamy MN, Rhead S, Schwarzbold AV, Singh N, Smith A, Song R, Snape MD, Sprinz E, Sutherland RK, Tarrant R, Thomson EC, Török ME, Toshner M, Turner DPJ, Vekemans J, Villafana TL, Watson MEE, Williams CJ, Douglas AD, Hill AVS, Lambe T, Gilbert SC, Pollard AJ, Oxford COVID Vaccine Trial Groupet al., 2021, Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK, The Lancet, Vol: 397, Pages: 99-111, ISSN: 0140-6736

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pin

Journal article

Kreisl WC, Kim M-J, Coughlin JM, Henter ID, Owen DR, Innis RBet al., 2020, PET imaging of neuroinflammation in neurological disorders, LANCET NEUROLOGY, Vol: 19, Pages: 940-950, ISSN: 1474-4422

Journal article

Nicholas R, Brooks D, Owen D, 2020, 18F-GE180, a radioligand for the TSPO protein: not ready for clinical trials in multiple sclerosis, EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, Vol: 47, Pages: 2242-2243, ISSN: 1619-7070

Journal article

Nutma E, Stephenson JA, Gorter RP, de Bruin J, Boucherie DM, Donat CK, Breur M, van der Valk P, Matthews P, Owen D, Amor Set al., 2019, A quantitative neuropathological assessment of translocator protein expression in multiple sclerosis, Brain, Vol: 142, Pages: 3440-3455, ISSN: 1460-2156

The 18kDa translocator protein (TSPO) is increasingly used to study brain and spinal cord inflammation in degenerative diseases of the CNS such as multiple sclerosis. The enhanced TSPO PET signal that arises during disease is widely-considered to reflect activated pathogenicmicroglia, although quantitative neuropathological data to support this interpretation has not been available. With the increasing interest in the role of chronic microglial activation in multiple sclerosis, characterising the cellular neuropathology associated with TSPO expression is of clear importance for understanding the cellular and pathological processes on which TSPO PET imaging is reporting.Here we have studied the cellular expression of TSPO and specific binding of two TSPO targeting radioligands ([3H]PK11195 and [3H]PBR28) in tissue sections from 42 multiple sclerosis cases and 12 age-matched controls. Markers of homeostatic and reactive microglia, astrocytes, and lymphocytes were used to investigate the phenotypes of cells expressing TSPO. There was an approximate 20-fold increase in cells double positive for TSPO and human leukocyte antigen -DR in active lesions and in the rim of chronic active lesion, relative to normal appearing white matter. TSPO was uniformly expressed across myeloid cells irrespective of their phenotype, rather than being preferentially associated with pro-inflammatory microglia or macrophages. TSPO+astrocytes were increased up to 7-fold compared to normal appearing white matter across all lesion sub-types and accounted for 25% of the TSPO+ cells in these lesions. To relate TSPO protein expression to ligand binding, specific binding of the TSPO ligands [3H]PK11195 and [3H]PBR28was determined in the same lesions. TSPO radioligand binding was increased up to seven times for [3H]PBR28 and up to two times for [3H]PK11195 in active lesions and the centre of chronic ac

Journal article

Sridharan S, Raffel J, Nandoskar A, Record C, Brooks DJ, Owen D, Sharp D, Muraro PA, Gunn R, Nicholas Ret al., 2019, Confirmation of specific binding of the 18 kDa translocator protein (TSPO) radioligand [18F]GE-180: a blocking study using XBD173 in multiple sclerosis normal appearing white and grey matter, Molecular Imaging and Biology, Vol: 21, Pages: 935-944, ISSN: 1536-1632

Purpose: Positron emission tomography (PET) ligands exhibit different levels of non-displaceable binding in vivo. In the case of ligands for the 18 kDa translocator protein (TSPO), the component of non-displaceable binding for the most widely used radiotracer, [11C]-(R)-PK11195, is relatively high compared to that for newer TSPO ligands. Non-displaceable binding is not often quantified in humans in vivo, partially due to a lack of available ligands that are known to be safe with which to displace binding to the target receptor. Recently, however, a technique has been developed to quantify the non-displaceable binding of TSPO tracers in vivo, by blocking the receptor with the TSPO ligand XBD173 and comparing the total volume of distribution ( ) pre and post-blockade. Here, we used an occupancy plot to quantify the non-displaceable binding ( ) of the TSPO PET tracers [18F]GE-180 and [11C]PBR28 in cohorts of people with multiple sclerosis (MS). We also compared plots of subjects carrying both high and mixed binding affinity polymorphisms of TSPO to estimate while potentially avoiding the need for receptor blockade.Procedures: Twelve people with multiple sclerosis (MS) and high (HAB) or mixed (MAB) affinity binding for TSPO underwent baseline MRI and 90-minute dynamic [18F]GE-180 PET (n=6; 3 HAB and 3 MAB) or [11C]PBR28 PET (n=6; 3 HAB, 3 MAB). Either one week later ([18F]GE-180) or the same afternoon ([11C]PBR28), participants had repeat PET following a 90mg dose of XBD173. PET images were co-registered with T1 MR volumetric images and regions of interest (ROIs) were defined using the 83-region Hammers atlas. Arterial blood sampling was used to generate plasma input functions for the two-tissue compartment model to quantify . The non-displaceable fraction of the total volume of distribution ( ) was calculated using two independent methods: the occupancy plot (by modelling the differences in signal post XBD173), and the polymorphism plot (by modelling the differences in

Journal article

Weinert M, Cowley SA, Alavian KN, Matthews PM, Owen DRet al., 2019, Exploring the mitochondrial TSPO protein as a possible immunometabolic modulatory target for treatment of multiple sclerosis, 35th Congress of the European-Committee-for-Treatment-and-Research-in-Multiple-Sclerosis (ECTRIMS) / 24th Annual Conference of Rehabilitation in MS, Publisher: SAGE PUBLICATIONS LTD, Pages: 515-515, ISSN: 1352-4585

Conference paper

Smith AM, Khozoie C, Fancy N, Srivastava P, Matthews PM, Owen D, Reynolds Ret al., 2019, Single nucleus RNA sequencing of post-mortem multiple sclerosis cortical grey matter, 35th Congress of the European-Committee-for-Treatment-and-Research-in-Multiple-Sclerosis (ECTRIMS) / 24th Annual Conference of Rehabilitation in MS, Publisher: SAGE PUBLICATIONS LTD, Pages: 233-233, ISSN: 1352-4585

Conference paper

Fancy NN, Srivastava P, Matthews PM, Owen DRet al., 2019, A bioinformatics approach to understand the regulation of TSPO gene expression in myeloid cells, 35th Congress of the European-Committee-for-Treatment-and-Research-in-Multiple-Sclerosis (ECTRIMS) / 24th Annual Conference of Rehabilitation in MS, Publisher: SAGE PUBLICATIONS LTD, Pages: 222-222, ISSN: 1352-4585

Conference paper

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