Abstract
We asked whether pharmacological stimulation of endogenous neural precursor cells (NPCs) may promote cognitive recovery and brain repair, focusing on the drug metformin, in parallel rodent and human studies of radiation injury. In the rodent cranial radiation model, we found that metformin enhanced the recovery of NPCs in the dentate gyrus, with sex-dependent effects on neurogenesis and cognition. A pilot double-blind, placebo-controlled crossover trial was conducted (ClinicalTrials.gov, NCT02040376) in survivors of pediatric brain tumors who had been treated with cranial radiation. Safety, feasibility, cognitive tests and MRI measures of white matter and the hippocampus were evaluated as endpoints. Twenty-four participants consented and were randomly assigned to complete 12-week cycles of metformin (A) and placebo (B) in either an AB or BA sequence with a 10-week washout period at crossover. Blood draws were conducted to monitor safety. Feasibility was assessed as recruitment rate, medication adherence and procedural adherence. Linear mixed modeling was used to examine cognitive and MRI outcomes as a function of cycle, sequence and treatment. We found no clinically relevant safety concerns and no serious adverse events associated with metformin. Sequence effects were observed for all cognitive outcomes in our linear mixed models. For the subset of participants with complete data in cycle 1, metformin was associated with better performance than placebo on tests of declarative and working memory. We present evidence that a clinical trial examining the effects of metformin on cognition and brain structure is feasible in long-term survivors of pediatric brain tumors and that metformin is safe to use and tolerable in this population. This pilot trial was not intended to test the efficacy of metformin for cognitive recovery and brain growth, but the preliminary results are encouraging and warrant further investigation in a large multicenter phase 3 trial.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Neurocognitive Dysfunction After Treatment for Pediatric Brain Tumors: Subtype-Specific Findings and Proposal for Brain Network-Informed Evaluations
Neuroscience Bulletin Open Access 24 August 2023
-
Irradiation and lithium treatment alter the global DNA methylation pattern and gene expression underlying a shift from gliogenesis towards neurogenesis in human neural progenitors
Translational Psychiatry Open Access 13 July 2023
-
Metformin and cancer hallmarks: shedding new lights on therapeutic repurposing
Journal of Translational Medicine Open Access 21 June 2023
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$209.00 per year
only $17.42 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout





Data availability
Requests for data related to the rodent studies should be directed to, and will be fulfilled by, senior corresponding author C.M.M. Requests for resources from the pilot clinical trial, including a copy of the trial protocol and aggregate data, should be directed to, and will be fulfilled by, senior corresponding author D.J.M. Data from individual participants in the pilot trial are not available owing to privacy and confidentiality and participants did not explicitly consent for their data to be shared.
References
Miller, F. D. & Kaplan, D. R. Mobilizing endogenous stem cells for repair and regeneration: are we there yet? Cell Stem Cell 10, 650–652 (2012).
Ming, G. L. & Song, H. Adult neurogenesis in the mammalian brain: significant answers and significant questions. Neuron 70, 687–702 (2011).
Lazarini, F. & Lledo, P. M. Is adult neurogenesis essential for olfaction? Trends Neurosci. 34, 20–30 (2011).
Wang, J. et al. Metformin activates an atypical PKC–CBP pathway to promote neurogenesis and enhance spatial memory formation. Cell Stem Cell 11, 23–35 (2012).
Chow, A. & Morshead, C. M. Cyclosporin A enhances neurogenesis in the dentate gyrus of the hippocampus. Stem Cell Res. 16, 79–87 (2016).
Scafidi, J. et al. Intranasal epidermal growth factor treatment rescues neonatal brain injury. Nature 506, 230–234 (2014).
Bridger, T., MacDonald, S., Baltzer, F. & Rodd, C. Randomized placebo-controlled trial of metformin for adolescents with polycystic ovary syndrome. Arch. Pediatr. Adolesc. Med. 160, 241–246 (2006).
Benavides, S., Striet, J., Germak, J. & Nahata, M. C. Efficacy and safety of hypoglycemic drugs in children with type 2 diabetes mellitus. Pharmacotherapy 25, 803–809 (2005).
Sun, J., Wang, Y., Zhang, X. & He, H. The effects of metformin on insulin resistance in overweight or obese children and adolescents: a PRISMA-compliant systematic review and meta-analysis of randomized controlled trials. Medicine 98, e14249 (2019).
Bjornstad, P. et al. Metformin improves insulin sensitivity and vascular health in youth With type 1 diabetes mellitus. Circulation 138, 2895–2907 (2018).
Anagnostou, E. et al. Metformin for treatment of overweight induced by atypical antipsychotic medication in young people with autism spectrum disorder: a randomized clinical trial. JAMA Psychiatry 73, 928–937 (2016).
Wang, J. et al. CBP histone acetyltransferase activity regulates embryonic neural differentiation in the normal and Rubinstein–Taybi syndrome brain. Dev. Cell 18, 114–125 (2010).
Dadwal, P. et al. Activating endogenous neural precursor cells using metformin leads to neural repair and functional recovery in a model of childhood brain injury. Stem Cell Rep. 5, 166–173 (2015).
Ruddy, R. M., Adams, K. V. & Morshead, C. M. Age- and sex-dependent effects of metformin on neural precursor cells and cognitive recovery in a model of neonatal stroke. Sci. Adv. 5, eaax1912 (2019).
Tanokashira, D. et al. Metformin treatment ameliorates diabetes-associated decline in hippocampal neurogenesis and memory via phosphorylation of insulin receptor substrate 1. FEBS Open Biol. 8, 1104–1118 (2018).
Ould-Brahim, F. et al. Metformin preconditioning of human induced pluripotent stem cell-derived neural stem cells promotes their engraftment and improves post-stroke regeneration and recovery. Stem Cells Dev. 27, 1085–1096 (2018).
Monje, M. L., Mizumatsu, S., Fike, J. R. & Palmer, T. D. Irradiation induces neural precursor-cell dysfunction. Nat. Med. 8, 955–962 (2002).
Monje, M. L., Toda, H. & Palmer, T. D. Inflammatory blockade restores adult hippocampal neurogenesis. Science 302, 1760–1765 (2003).
Redmond, K. J., Mahone, E. M. & Horska, A. Association between radiation dose to neuronal progenitor cell niches and temporal lobes and performance on neuropsychological testing in children: a prospective study. Neuro Oncol. 15, 1455 (2013).
Roughton, K., Kalm, M. & Blomgren, K. Sex-dependent differences in behavior and hippocampal neurogenesis after irradiation to the young mouse brain. Eur. J. Neurosci. 36, 2763–2772 (2012).
Riggs, L. et al. Changes to memory structures in children treated for posterior fossa tumors. J. Int. Neuropsychol. Soc. 20, 168–180 (2014).
Decker, A. L. et al. Smaller hippocampal subfield volumes predict verbal associative memory in pediatric brain tumor survivors. Hippocampus 27, 1140–1154 (2017).
Scantlebury, N. et al. White matter and information processing speed following treatment with cranial-spinal radiation for pediatric brain tumor. Neuropsychology 30, 425–438 (2016).
Krull, K. R., Hardy, K. K., Kahalley, L. S., Schuitema, I. & Kesler, S. R. Neurocognitive outcomes and interventions in long-term survivors of childhood cancer. J. Clin. Oncol. 36, 2181–2189 (2018).
Rola, R. et al. Radiation-induced impairment of hippocampal neurogenesis is associated with cognitive deficits in young mice. Exp. Neurol. 188, 316–330 (2004).
Fukuda, A. et al. Age-dependent sensitivity of the developing brain to irradiation is correlated with the number and vulnerability of progenitor cells. J. Neurochem. 92, 569–584 (2005).
Hellstrom, N. A., Bjork-Eriksson, T., Blomgren, K. & Kuhn, H. G. Differential recovery of neural stem cells in the subventricular zone and dentate gyrus after ionizing radiation. Stem Cells 27, 634–641 (2009).
Ruddy, R. M., Derkach, D., Dadwal, P. & Morshead, C. M. Cranial irradiation in juvenile mice leads to early and sustained defects in the stem and progenitor cell pools and late cognitive impairments. Brain Res. 1727, 146548 (2019).
Sorrells, S. F. et al. Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults. Nature 555, 377–381 (2018).
Moreno-Jiménez, E. P. et al. Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease. Nat. Med. 25, 554–560 (2019).
Lebel, C. & Beaulieu, C. Longitudinal development of human brain wiring continues from childhood into adulthood. J. Neurosci. 31, 10937–10947 (2011).
Chang, A., Nishiyama, A., Peterson, J., Prineas, J. & Trapp, B. D. NG2-positive oligodendrocyte progenitor cells in adult human brain and multiple sclerosis lesions. J. Neurosci. 20, 6404–6412 (2000).
Gershon, R. C. et al. NIH Toolbox for assessment of neurological and behavioral function. Neurology 80, S2–S6 (2013).
Talley, J. L. Children’s Auditory Verbal Learning Test-2. Professional Manual (Psychological Assessment Resources, 1993).
Schmidt, M. Rey Auditory Verbal Learning Test: RAVLT: a handbook (Western Psychological Services, 1996).
CANTAB® (cognitive assessment software) http://www.cantab.com/ (Cambridge Cognition, 2018).
Grizzle, J. E. The two-period change-over design and its use in clinical trials. Biometrics 21, 467–480 (1965).
Fieremans, E., Jensen, J. H. & Helpern, J. A. White matter characterization with diffusional kurtosis imaging. Neuroimage 58, 177–188 (2011).
Jelescu, I. O. et al. In vivo quantification of demyelination and recovery using compartment-specific diffusion MRI metrics validated by electron microscopy. Neuroimage 132, 104–114 (2016).
Smith, S. M. et al. Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data. Neuroimage 31, 1487–1505 (2006).
Pereira, A. C. et al. An in vivo correlate of exercise-induced neurogenesis in the adult dentate gyrus. Proc. Natl Acad. Sci. USA 104, 5638–5643 (2007).
Kahalley, L. S. et al. Superior intellectual outcomes after proton radiotherapy compared with photon radiotherapy for pediatric medulloblastoma. J. Clin. Oncol. 38, 454–461 (2020).
Moxon-Emre, I. et al. Impact of craniospinal dose, boost volume, and neurologic complications on intellectual outcome in patients with medulloblastoma. J. Clin. Oncol. 32, 1760–1768 (2014).
Wellek, S. & Blettner, M. On the proper use of the crossover design in clinical trials: part 18 of a series on evaluation of scientific publications. Dtsch. Arztebl. Int. 109, 276–281 (2012).
Zammit, A. R. et al. Roles of hippocampal subfields in verbal and visual episodic memory. Behav. Brain Res. 317, 157–162 (2017).
Zheng, F. et al. The volume of hippocampal subfields in relation to decline of memory recall across the adult lifespan. Front. Aging Neurosci. 10, 320 (2018).
Leszczynski, M. How does hippocampus contribute to working memory processing?. Front. Hum. Neurosci. 5, 168 (2011).
Curtis, E. et al. A first-in-human, phase I study of neural stem cell transplantation for chronic spinal cord injury. Cell Stem Cell 22, 941–950 (2018).
Gupta, N. et al. Neural stem cell engraftment and myelination in the human brain. Sci. Transl. Med. 4, 155ra137 (2012).
Ou, Z. et al. Metformin treatment prevents amyloid plaque deposition and memory impairment in APP/PS1 mice. Brain Behav. Immun. 69, 351–363 (2018).
Gantois, I. et al. Metformin ameliorates core deficits in a mouse model of fragile X syndrome. Nat. Med. 23, 674–677 (2017).
Luchsinger, J. A. et al. Metformin in amnestic mild cognitive impairment: results of a pilot randomized placebo controlled clinical trial. J. Alzheimers Dis. 51, 501–514 (2016).
Lin, Y. et al. Evaluation of metformin on cognitive improvement in patients with non-dementia vascular cognitive impairment and abnormal glucose metabolism. Front. Aging Neurosci. 10, 227 (2018).
Dy, A. B. C. et al. Metformin as targeted treatment in fragile X syndrome. Clin. Genet. 93, 216–222 (2018).
Gibson, E. M. et al. Neuronal activity promotes oligodendrogenesis and adaptive myelination in the mammalian brain. Science 344, 1252304 (2014).
Sato, Y. et al. Grafting neural stem and progenitor cells into the hippocampus of juvenile, irradiated mice normalizes behavior deficits. Front. Neurol. 9, 715 (2018).
Babona-Pilipos, R., Popovic, M. R. & Morshead, C. M. A galvanotaxis assay for analysis of neural precursor cell migration kinetics in an externally applied direct current electric field. J. Vis. Exp. 2012, 4193 (2012).
Coles-Takabe, B. L. et al. Don’t look: growing clonal versus nonclonal neural stem cell colonies. Stem Cells 26, 2938–2944 (2008).
Nusrat, L. et al. Cyclosporin A-mediated activation of endogenous neural precursor cells promotes cognitive recovery in a mouse model of stroke. Front. Aging Neurosci. 10, 93 (2018).
Spiller, H. A. & Quadrani, D. A. Toxic effects from metformin exposure. Ann. Pharmacother. 38, 776–780 (2004).
Hsia, Y. et al. Unlicensed use of metformin in children and adolescents in the UK. Br. J. Clin. Pharmacol. 73, 135–139 (2012).
Vakil, E., Greenstein, Y. & Blachstein, H. Normative data for composite scores for children and adults derived from the Rey Auditory Verbal Learning Test. Clin. Neuropsychol. 24, 662–677 (2010).
Riggs, L. et al. Exercise training for neural recovery in a restricted sample of pediatric brain tumor survivors: a controlled clinical trial with crossover of training versus no training. Neuro Oncol. 19, 440–450 (2017).
Dale, A. M., Fischl, B. & Sereno, M. I. Cortical surface-based analysis. I. Segmentation and surface reconstruction. Neuroimage 9, 179–194 (1999).
Fischl, B., Liu, A. & Dale, A. M. Automated manifold surgery: constructing geometrically accurate and topologically correct models of the human cerebral cortex. IEEE Trans. Med. Imaging 20, 70–80 (2001).
Ades-Aron, B. et al. Evaluation of the accuracy and precision of the diffusion parameter EStImation with Gibbs and NoisE removal pipeline. Neuroimage 183, 532–543 (2018).
Veraart, J. et al. Denoising of diffusion MRI using random matrix theory. Neuroimage 142, 394–406 (2016).
Veraart, J., Fieremans, E. & Novikov, D. S. Diffusion MRI noise mapping using random matrix theory. Magn. Reson. Med. 76, 1582–1593 (2016).
Kellner, E., Dhital, B., Kiselev, V. G. & Reisert, M. Gibbs-ringing artifact removal based on local subvoxel-shifts. Magn. Reson. Med. 76, 1574–1581 (2016).
Andersson, J. L. R. & Sotiropoulos, S. N. An integrated approach to correction for off-resonance effects and subject movement in diffusion MR imaging. Neuroimage 125, 1063–1078 (2016).
Collier, Q., Veraart, J., Jeurissen, B., den Dekker, A. J. & Sijbers, J. Iterative reweighted linear least squares for accurate, fast, and robust estimation of diffusion magnetic resonance parameters. Magn. Reson. Med. 73, 2174–2184 (2015).
Avants, B. B. et al. The Insight Toolkit image registration framework. Front. Neuroinformatics 8, 44 (2014).
Engvig, A. et al. Memory training impacts short-term changes in aging white matter: a longitudinal diffusion tensor imaging study. Hum. Brain Mapp. 33, 2390–2406 (2012).
Jenkinson, M. & Smith, S. A global optimisation method for robust affine registration of brain images. Med. Image Anal. 5, 143–156 (2001).
Jenkinson, M., Bannister, P., Brady, M. & Smith, S. Improved optimization for the robust and accurate linear registration and motion correction of brain images. Neuroimage 17, 825–841 (2002).
Shirzadi, Z., Crane, D. E., Robertson, A. D. & Maralani, P. J. Automated removal of spurious intermediate cerebral blood flow volumes improves image quality among older patients: a clinical arterial spin labeling investigation.J. Magn. Reson. Imaging 42, 1377–1385 (2015).
van Osch, M. J. et al. Quantitative cerebral perfusion MRI and CO2 reactivity measurements in patients with symptomatic internal carotid artery occlusion. Neuroimage 17, 469–478 (2002).
Hendrikse, J. et al. Internal carotid artery occlusion assessed at pulsed arterial spin-labeling perfusion MR imaging at multiple delay times. Radiology 233, 899–904 (2004).
Faul, F., Erdfelder, E., Lang, A.-G. & Buchner, A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Res, Methods 39, 175–191 (2007).
Acknowledgements
We wish to thank A. Willan, Clinical Trials Methodologist, Ontario Child Health Support Unit, Research Institute, The Hospital for Sick Children, for consulting on and developing our analytic approach while blind to the trial data. We also wish to thank the research personnel and clinical staff who made this trial possible, particularly V. Ramaswamy, U. Bartels, U. Tabori and A. Huang, as well as N. Sarvaria, D. Thomas, E. Barlev, J. Dutton, J. Gammon, L. Lauer, A. Decker, A. Ferkul, D. McRae, T. Rayner, R. Weiss and M. Lalancette. We would also like to thank J. Wang, D. Kaplan and P. Frankland for frequent discussions and advice during the course of this work. Finally, we wish to thank J. Tseng for her technical support in improving the presentation of our figures. This work was supported by grants from Brain Canada (F.D.M., D.J.M., C.M.M.), the Stem Cell Network (F.D.M., D.J.M., C.M.M.), the Ontario Institute for Regenerative Medicine (F.D.M., D.J.M., C.M.M.), Medicine By Design (CFREF), and the Garron Family Cancer Centre (D.J.M., E.B.). R.M.R. was supported by a CIHR graduate student fellowship.
Author information
Authors and Affiliations
Contributions
Conceptualization, R.M.R., E.B., F.D.M., C.M.M. and D.J.M.; methodology, R.A., R.M.R., E.B., C.M.M. and D.J.M.; software, B.A., Z.S., E.F. and B.J.M.; formal analysis, R.A., R.M.R., E.C., A.O., D.D., C.B.d.M., E.B., C.M.M. and D.J.M.; investigation, R.M.R., C.B.d.M., J.S., E.B., C.M.M. and D.J.M.; resources, S.L., B.A., Z.S., E.F., B.J.M., E.B., C.M.M. and D.J.M.; data curation, R.A., R.M.R., D.D., C.B.d.M. and J.S.; writing—original draft, R.A., R.M.R., F.D.M., C.M.M. and D.J.M.; writing—review and editing, R.A., R.M.R., E.C., A.O., D.D., B.A., Z.S., E.F., B.J.M., C.B.d.M., J.S., E.B., F.D.M., C.M.M. and D.J.M.; supervision, C.M.M. and D.J.M.; project administration, C.B.d.M., J.S. and D.J.M.; funding acquisition, F.D.M., C.M.M. and D.J.M.
Corresponding authors
Ethics declarations
Competing interests
E.F. is a co-inventor and the New York University Grossman School of Medicine is owner of the denoising technology used in this manuscript as part of the routine data image processing pipeline; a patent application has been filed and is pending. E.F., B.A. and the New York University Grossman School of Medicine are shareholders and have advisory roles at Microstructure Imaging, Inc. The remaining authors do not have any competing interests to declare.
Additional information
Peer review information Kate Gao and Javier Carmona were the primary editors on this article and managed its editorial process and peer review in collaboration with the rest of the editorial team.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data
Extended Data Fig. 1 Metformin in the absence of injury has no significant effect on the number of neurospheres or on behavioural assays.
a, b, Fold change in the number of neurospheres from the (a) SVZ (n = 21 Ctrl, 19 Met mice over 10 independent experiments; t(38) = 0.10, p = 0.92) and (b) DG (n = 12 Ctrl, 10 Met mice over 5 independent experiments; t(20) = 0.90, p = 0.38) 5 weeks post-radiation. c, Spontaneous alternation performance measured using the Y maze at P43 (n = 38 Ctrl, 31 Met mice over 14 independent experiments; t(67) = 0.34, p = 0.74). d, Percentage of time spent exploring objects in a novel place measured using the novel place recognition task from P44-46 (n = 34 Ctrl, 27 Met over 13 independent experiments; t(59) = 0.70, p = 0.48). Two-sided unpaired t-test was used for all analyses. Data is presented as mean ± SEM.
Extended Data Fig. 2 Metformin’s effects on NSC pool recovery following juvenile cranial radiation are not sex-dependent.
a, b, Fold change in the number of neurospheres from the SVZ 5 weeks post-radiation in (a) females (n = 8 Ctrl, 9 IR, 6 IR + Met mice over 6 independent experiments; F(2,20) = 0.56, p = 0.58) and (b) males (n = 9 Ctrl, 7 IR, 12 IR+Met mice over 6 independent experiments; F(2,25) = 0.03, p = 0.97). (c-d) Fold change in the number of neurospheres from the DG 5 weeks post-radiation in (c) females (n = 6 Ctrl, 5 IR, 6 IR+Met mice over 4 independent experiments; F(2,14) = 3.47, p = 0.06; Ctrl vs. IR, p = 0.0496) and (d) males (n = 4 Ctrl, 5 IR, 4 IR+Met over 4 independent experiments; F(2,10) = 6.47, p = 0.02; Ctrl vs. IR, p = 0.04; IR vs. IR+Met, p = 0.02). *p < 0.05, one-way ANOVA with Tukey’s test was used for all analyses. Data is presented as mean ± SEM.
Extended Data Fig. 3 Cranial radiation does not lead to impairments in the open field test or in the elevated plus maze.
a, Experimental paradigm. IR=cranial radiation. b, c, Path length travelled over 10 minutes in an open arena by (b) females (n = 17 Ctrl, 15 IR, 13 IR+Met mice over 13 independent experiments; F(2,42) = 0.62, p = 0.54) and (c) males (n = 17 Ctrl, 19 IR, 19 IR+Met mice over 13 independent experiments; F(2,52) = 0.40, p = 0.67). d, e, Percentage of time spent in the open arms of the elevated plus maze over 10 minutes by (d) females (n = 5 Ctrl, 5 IR, 6 IR+Met mice over 4 independent experiments; F(2,13) = 1.26, p = 0.32) and (e) males (n = 5 Ctrl, 5 IR, 6 IR+Met mice over 4 independent experiments; F(2,13) = 0.78, p = 0.48). One-way ANOVA with Tukey’s test was used for all analyses. Data is presented as mean ± SEM.
Extended Data Fig. 4 Consort table.
Eligible participants were identified via database review. Randomization was conducted by the Research Support Pharmacy and all research personnel remained blind to treatment assignment until all participants had completed the trial and data processing and scoring was completed. Initially, due to the pilot nature of the trial, neuroimaging and neuropsychological assessments were acquired at three time points (Baseline 1 and 2; Outcome 2). With an amendment to the study protocol, subsequent participants were assessed at four time points (Baseline 1 and 2; Outcome 1 and 2). Therefore, fewer Outcome 1 than Outcome 2 data points were acquired. Linear mixed modeling can be used in the context of such missing data. The single participant who consented but did not complete the trial was not included in the analyses.
Extended Data Fig. 5 Estimated marginal means for linear mixed models of cognitive and WMTI outcomes.
Data are presented as estimated marginal means from seperate general linear mixed models (two sided) with two sets of outcomes (Outcome 1 and 2 corresponding to the end of the first and second 12-week treatment cycles, respectively). We examined the fixed effects of cycle (the first versus second 12-week treatment cycle), treatment (metformin versus placebo), and sequence (metformin first, placebo second [AB] versus placebo first, metformin second [BA]). Bar graphs show estimated means+/- SEMs from the following model: Outcome measure = cycle + treatment + sequence + covariate (Baseline measure) + (1| participant ID)+ε, where cycle, treatment, and sequence are independent fixed effects and where the measures are: a) total correct on the LSWM (n = 23); b) CANTAB mean latency (n = 22); c) total number of words recall for immediate recall (n = 23); and d) AWF. Standard error bars are shown for each estimated mean. All models were corrected for multiple comparisons (False Discovery Rate (FDR) q < .10): * p < 0.05, ** q < 0.10 from the linear mixed models (Panel a-c, qs = 0.09; Panel d, q = 0.08).
Extended Data Fig. 6 Voxel wise analyses of treatment effects.
We used a longitudinal voxel wise approach to test for clusters of significant changes in AWF and De,⊥ following metformin in all participants using Tract Based Spatial Statistics (TBSS). For 2 sided comparisons across treatment conditions, individual difference maps for AWF and De,⊥ (post-metformin minus pre-metformin) were projected onto the skeleton and tested for voxels where change was significantly different from zero using threshold-free cluster enhancement (TFCE). For these analyses, the null distribution of the cluster-size statistic was built up over 5000 random permutations. Cluster size was thresholded at P < 0.05, which is family wise fully corrected for multiple comparisons across space. Images are presented in the axial frame in radiological convention within Montreal Neurological Institute (MNI) Z-coordinates. The white matter skeleton is displayed in blue. No significant clusters of change were evident for AWF (p = .90) or De,⊥ (p = .47) across the white matter skeleton.
Extended Data Fig. 7 Arterial Spin Labelling and Cerebral Blood Flow within the Hippocampus as a function of cycle, treatment, and sequence effects for the right and left hippocampi and adjusted for baseline hippocampal CBF.
a, Axial T1-weighted image with FreeSurfer hippocampus segmentation shown. b, PASL image processing pipeline shown in the axial plane, including PASL Control, PASL Labeled image, Perfusion weighted Image and Cerebral Blood Flow Map. c, Segmented hippocampi registered to the CBF map. Boxplots showing all data points at baseline and outcome assessment with the mean (dashed line) and median (solid line) sequence group observations for CBF (ml/100 g/min) for: the left hippocampus at d) Cycle 1 and e) Cycle 2; and the right hippocampus at f) Cycle 1 and g) Cycle 2. Metformin treatment condition is shown in red and placebo in blue. The upper and lower limits of the box plots are the third and first quartiles (75th and 25th percentile), respectively. The whiskers extend up to 1.5 times the interquartile range from the top (bottom) of the box to the furthest datum within that distance: Data beyond this distance are represented individually as points.
Supplementary information
Rights and permissions
About this article
Cite this article
Ayoub, R., Ruddy, R.M., Cox, E. et al. Assessment of cognitive and neural recovery in survivors of pediatric brain tumors in a pilot clinical trial using metformin. Nat Med 26, 1285–1294 (2020). https://doi.org/10.1038/s41591-020-0985-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41591-020-0985-2
This article is cited by
-
Metformin and cancer hallmarks: shedding new lights on therapeutic repurposing
Journal of Translational Medicine (2023)
-
Irradiation and lithium treatment alter the global DNA methylation pattern and gene expression underlying a shift from gliogenesis towards neurogenesis in human neural progenitors
Translational Psychiatry (2023)
-
Cerebellar mutism syndrome of non-tumour surgical aetiology—a case report and literature review
Child's Nervous System (2023)
-
The Dialogue Between Neuroinflammation and Adult Neurogenesis: Mechanisms Involved and Alterations in Neurological Diseases
Molecular Neurobiology (2023)
-
Neurocognitive Dysfunction After Treatment for Pediatric Brain Tumors: Subtype-Specific Findings and Proposal for Brain Network-Informed Evaluations
Neuroscience Bulletin (2023)