Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Exosome-eluting stents for vascular healing after ischaemic injury

A Publisher Correction to this article was published on 20 April 2021

This article has been updated

Abstract

Drug-eluting stents implanted after ischaemic injury reduce the proliferation of endothelial cells and vascular smooth muscle cells and thus neointimal hyperplasia. However, the eluted drug also slows down the re-endothelialization process, delays arterial healing and can increase the risk of late restenosis. Here we show that stents releasing exosomes derived from mesenchymal stem cells in the presence of reactive oxygen species enhance vascular healing in rats with renal ischaemia-reperfusion injury, promoting endothelial cell tube formation and proliferation, and impairing the migration of smooth muscle cells. Compared with drug-eluting stents and bare-metal stents, the exosome-coated stents accelerated re-endothelialization and decreased in-stent restenosis 28 days after implantation. We also show that exosome-eluting stents implanted in the abdominal aorta of rats with unilateral hindlimb ischaemia regulated macrophage polarization, reduced local vascular and systemic inflammation, and promoted muscle tissue repair.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Fabrication and characterization of EES.
Fig. 2: In vitro ROS-trigged exosome release and biocompatibility of EES.
Fig. 3: EES promotes the proliferation and migration of endothelial cells but inhibits the migration of SMCs.
Fig. 4: Stenting in the abdominal aorta of rats.
Fig. 5: Neointimal formation with different stents.
Fig. 6: Local inflammation and immune-modulation effects of stent implantation.
Fig. 7: Restoration of blood flow and muscle repair in the ischaemic limbs of Apoe−/− rats after EES treatment.

Similar content being viewed by others

Data availability

The main data supporting the results in this study are available within the paper and its Supplementary Information. The raw and analysed datasets generated during the study are too large to be publicly shared, but are available for research purposes from the corresponding author on reasonable request. GeneQuery rat macrophage polarization markers qPCR array data are available on the NCBI database with the identifier GSE155793. ToF-SIMS, XPS and histopathological data are available on reasonable request.

Change history

References

  1. Tayal, R. et al. Totally percutaneous insertion and removal of impella device using axillary artery in the setting of advanced peripheral artery disease. J. Invasive Cardiol. 28, 374–380 (2016).

    PubMed  Google Scholar 

  2. Khawaja, F. J. & Kullo, I. J. Novel markers of peripheral arterial disease. Vasc. Med. 14, 381–392 (2009).

    Article  PubMed  PubMed Central  Google Scholar 

  3. Katsanos, K. et al. Wound healing outcomes and health-related quality-of-life changes in the achilles trial: 1-year results from a prospective randomized controlled trial of infrapopliteal balloon angioplasty versus sirolimus-eluting stenting in patients with ischemic peripheral arterial disease. JACC Cardiovasc. Interv. 9, 259–267 (2016).

    Article  PubMed  Google Scholar 

  4. Alfonso, F., Byrne, R. A., Rivero, F. & Kastrati, A. Current treatment of in-stent restenosis. J. Am. Coll. Cardiol. 63, 2659–2673 (2014).

    Article  PubMed  Google Scholar 

  5. Brasen, J. H. et al. Angiogenesis, vascular endothelial growth factor and platelet-derived growth factor-BB expression, iron deposition, and oxidation-specific epitopes in stented human coronary arteries. Arterioscler. Thromb. Vasc. Biol. 21, 1720–1726 (2001).

    Article  CAS  PubMed  Google Scholar 

  6. McGinty, S., Vo, T. T., Meere, M., McKee, S. & McCormick, C. Some design considerations for polymer-free drug-eluting stents: a mathematical approach. Acta Biomater. 18, 213–225 (2015).

    Article  CAS  PubMed  Google Scholar 

  7. Worthley, S. G. et al. First-in-human evaluation of a novel polymer-free drug-filled stent: angiographic, IVUS, OCT, and clinical outcomes from the RevElution study. JACC Cardiovasc. Interv. 10, 147–156 (2017).

    Article  PubMed  Google Scholar 

  8. Nakazawa, G. et al. Anti-CD34 antibodies immobilized on the surface of sirolimus-eluting stents enhance stent endothelialization. JACC Cardiovasc. Interv. 3, 68–75 (2010).

    Article  PubMed  Google Scholar 

  9. Karjalainen, P. P. & Nammas, W. Titanium-nitride-oxide-coated coronary stents: insights from the available evidence. Ann. Med. 49, 299–309 (2017).

    Article  CAS  PubMed  Google Scholar 

  10. Rani, S., Ryan, A. E., Griffin, M. D. & Ritter, T. Mesenchymal stem cell-derived extracellular vesicles: toward cell-free therapeutic applications. Mol. Ther. 23, 812–823 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Zhang, K. & Li, Z. Molecular imaging of therapeutic effect of mesenchymal stem cell-derived exosomes for hindlimb ischemia treatment. Methods Mol. Biol. 2150, 213–225 (2020).

    Article  CAS  PubMed  Google Scholar 

  12. Vandergriff, A. et al. Targeting regenerative exosomes to myocardial infarction using cardiac homing peptide. Theranostics 8, 1869–1878 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Aghajani Nargesi, A., Lerman, L. O. & Eirin, A. Mesenchymal stem cell-derived extracellular vesicles for kidney repair: current status and looming challenges. Stem Cell Res. Ther. 8, 273 (2017).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  14. Mendt, M., Rezvani, K. & Shpall, E. Mesenchymal stem cell-derived exosomes for clinical use. Bone Marrow Transplant. 54, 789–792 (2019).

    Article  PubMed  Google Scholar 

  15. Forsberg, M. H., Kink, J. A., Hematti, P. & Capitini, C. M. Mesenchymal stromal cells and exosomes: progress and challenges. Front. Cell Dev. Biol. 8, 665 (2020).

    Article  PubMed  PubMed Central  Google Scholar 

  16. Nassar, W. et al. Umbilical cord mesenchymal stem cells derived extracellular vesicles can safely ameliorate the progression of chronic kidney diseases. Biomater. Res. 20, 21 (2016).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  17. Yang, J., Zhang, X., Chen, X., Wang, L. & Yang, G. Exosome mediated delivery of miR-124 promotes neurogenesis after ischemia. Mol. Ther. Nucleic Acids 7, 278–287 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Bian, X., Ma, K., Zhang, C. & Fu, X. Therapeutic angiogenesis using stem cell-derived extracellular vesicles: an emerging approach for treatment of ischemic diseases. Stem Cell Res. Ther. 10, 158 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  19. Tsimikas, S. et al. Percutaneous coronary intervention results in acute increases in oxidized phospholipids and lipoprotein(a): short-term and long-term immunologic responses to oxidized low-density lipoprotein. Circulation 109, 3164–3170 (2004).

    Article  CAS  PubMed  Google Scholar 

  20. Laurindo, F. R. et al. Evidence for superoxide radical-dependent coronary vasospasm after angioplasty in intact dogs. Circulation 83, 1705–1715 (1991).

    Article  CAS  PubMed  Google Scholar 

  21. Galkina, E. & Ley, K. Immune and inflammatory mechanisms of atherosclerosis. Annu. Rev. Immunol. 27, 165–197 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  22. Bennett, M. R., Sinha, S. & Owens, G. K. Vascular smooth muscle cells in atherosclerosis. Circ. Res. 118, 692–702 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Raines, E. W. The extracellular matrix can regulate vascular cell migration, proliferation, and survival: relationships to vascular disease. Int. J. Exp. Pathol. 81, 173–182 (2000).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Su, Z. et al. ROS-triggered and regenerating anticancer nanosystem: an effective strategy to subdue tumor’s multidrug resistance. J. Control. Release 196, 370–383 (2014).

    Article  CAS  PubMed  Google Scholar 

  25. Hulsmans, M. & Holvoet, P. MicroRNA-containing microvesicles regulating inflammation in association with atherosclerotic disease. Cardiovasc. Res. 100, 7–18 (2013).

    Article  CAS  PubMed  Google Scholar 

  26. Oikawa, S., Wada, S., Lee, M., Maeda, S. & Akimoto, T. Role of endothelial microRNA-23 clusters in angiogenesis in vivo. Am. J. Physiol. 315, H838–H846 (2018).

    CAS  Google Scholar 

  27. Cheng, J., Zhang, P. & Jiang, H. Let-7b-mediated pro-survival of transplanted mesenchymal stem cells for cardiac regeneration. Stem Cell Res. Ther. 6, 216 (2015).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  28. Castner, D. G. & Ratner, B. D. Biomedical surface science: foundations to frontiers. Surf. Sci. 500, 28–60 (2002).

    Article  CAS  Google Scholar 

  29. Draude, F. et al. Characterization of freeze-fractured epithelial plasma membranes on nanometer scale with ToF-SIMS. Anal. Bioanal. 407, 2203–2211 (2015).

    Article  CAS  Google Scholar 

  30. Chung, T. W., Liu, D. Z., Wang, S. Y. & Wang, S. S. Enhancement of the growth of human endothelial cells by surface roughness at nanometer scale. Biomaterials 24, 4655–4661 (2003).

    Article  CAS  PubMed  Google Scholar 

  31. Xu, L. C., Bauer, J. W. & Siedlecki, C. A. Proteins, platelets, and blood coagulation at biomaterial interfaces. Colloid Surf. B 124, 49–68 (2014).

    Article  CAS  Google Scholar 

  32. de Gracia Lux, C. et al. Biocompatible polymeric nanoparticles degrade and release cargo in response to biologically relevant levels of hydrogen peroxide. J. Am. Chem. Soc. 134, 15758–15764 (2012).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  33. Starke, R. D. et al. Endothelial von Willebrand factor regulates angiogenesis. Blood 117, 1071–1080 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Rensen, S. S., Doevendans, P. A. & van Eys, G. J. Regulation and characteristics of vascular smooth muscle cell phenotypic diversity. Neth. Heart J. 15, 100–108 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Langeveld, B. et al. Rat abdominal aorta stenting: a new and reliable small animal model for in-stent restenosis. J. Vasc. Res. 41, 377–386 (2004).

    Article  PubMed  Google Scholar 

  36. Tsai, Y. C. et al. Angiopoietin-2, Angiopoietin-1 and subclinical cardiovascular disease in chronic kidney disease. Sci. Rep. 6, 39400 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  37. Wasik, U., Milkiewicz, M., Kempinska-Podhorodecka, A. & Milkiewicz, P. Protection against oxidative stress mediated by the Nrf2/Keap1 axis is impaired in primary biliary cholangitis. Sci. Rep. 7, 44769 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  38. Douglas, G. et al. Endothelial cell repopulation after stenting determines in-stent neointima formation: effects of bare-metal vs. drug-eluting stents and genetic endothelial cell modification. Eur. Heart J. 34, 3378–3388 (2013).

    Article  CAS  PubMed  Google Scholar 

  39. Bedair, T. M., ElNaggar, M. A., Joung, Y. K. & Han, D. K. Recent advances to accelerate re-endothelialization for vascular stents. J. Tissue Eng. 8, 2041731417731546 (2017).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  40. Tan, A., Alavijeh, M. S. & Seifalian, A. M. Next generation stent coatings: convergence of biotechnology and nanotechnology. Trends Biotechnol. 30, 406–409 (2012).

    Article  CAS  PubMed  Google Scholar 

  41. Getz, G. S. & Reardon, C. A. Animal models of atherosclerosis. Arterioscler. Thromb. Vasc. Biol. 32, 1104–1115 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. Lee, J. G. et al. Knockout rat models mimicking human atherosclerosis created by Cpf1-mediated gene targeting. Sci. Rep. 9, 2628 (2019).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  43. Allahverdian, S., Chaabane, C., Boukais, K., Francis, G. A. & Bochaton-Piallat, M. L. Smooth muscle cell fate and plasticity in atherosclerosis. Cardiovasc. Res. 114, 540–550 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  44. Greenberger, S. & Bischoff, J. Pathogenesis of infantile haemangioma. Br. J. Dermatol. 169, 12–19 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Yonetsu, T. et al. Comparison of incidence and time course of neoatherosclerosis between bare metal stents and drug-eluting stents using optical coherence tomography. Am. J. Cardiol. 110, 933–939 (2012).

    Article  CAS  PubMed  Google Scholar 

  46. Slevin, M., Krupinski, J. & Badimon, L. Controlling the angiogenic switch in developing atherosclerotic plaques: possible targets for therapeutic intervention. J. Angiogenes. Res. 1, 4 (2009).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  47. He, X. et al. MSC-derived exosome promotes M2 polarization and enhances cutaneous wound healing. Stem Cells Int. 2019, 7132708 (2019).

    PubMed  PubMed Central  Google Scholar 

  48. Mahdavi Gorabi, A. et al. The role of mesenchymal stem cells in atherosclerosis: prospects for therapy via the modulation of inflammatory milieu. J. Clin. Med. 8, 1413 (2019).

    Article  PubMed Central  CAS  Google Scholar 

  49. Li, J. et al. Exosomes derived from mesenchymal stem cells attenuate the progression of atherosclerosis in ApoE−/− mice via miR-let7 mediated infiltration and polarization of M2 macrophage. Biochem. Bioph. Res. Commun. 510, 565–572 (2019).

    Article  CAS  Google Scholar 

  50. Boss, M., Kemmerer, M., Brüne, B. & Namgaladze, D. FABP4 inhibition suppresses PPARγ activity and VLDL-induced foam cell formation in IL-4-polarized human macrophages. Atherosclerosis 240, 424–430 (2015).

    Article  CAS  PubMed  Google Scholar 

  51. Koltsova, E. K. et al. Interleukin-27 receptor limits atherosclerosis in Ldlr−/− mice. Circ. Res. 111, 1274–1285 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. Van Weel, V. et al. Natural killer cells and CD4+ T-cells modulate collateral artery development. Arterioscler. Thromb. Vasc. Biol. 27, 2310–2318 (2007).

    Article  PubMed  CAS  Google Scholar 

  53. Welt, F. G. & Rogers, C. Inflammation and restenosis in the stent era. Arterioscler. Thromb. Vasc. Biol. 22, 1769–1776 (2002).

    Article  CAS  PubMed  Google Scholar 

  54. Vandergriff, A. C. et al. Intravenous cardiac stem cell-derived exosomes ameliorate cardiac dysfunction in doxorubicin induced dilated cardiomyopathy. Stem Cells Int. 2015, 960926 (2015).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  55. Qiao, L. et al. MicroRNA-21-5p dysregulation in exosomes derived from heart failure patients impairs regenerative potential. J. Clin. Invest. 129, 2237–2250 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  56. Xu, Q., He, C., Xiao, C. & Chen, X. Reactive oxygen species (ROS) responsive polymers for biomedical applications. Macromol. Biosci. 16, 635–646 (2016).

    Article  CAS  PubMed  Google Scholar 

  57. Gallet, R. et al. Exosomes secreted by cardiosphere-derived cells reduce scarring, attenuate adverse remodelling, and improve function in acute and chronic porcine myocardial infarction. Eur. Heart J. 38, 201–211 (2017).

    CAS  PubMed  Google Scholar 

  58. Zhang, B. et al. Mesenchymal stromal cell exosome-enhanced regulatory T-cell production through an antigen-presenting cell-mediated pathway. Cytotherapy 20, 687–696 (2018).

    Article  CAS  PubMed  Google Scholar 

  59. Poh, K. K. et al. Repeated direct endomyocardial transplantation of allogeneic mesenchymal stem cells: safety of a high dose, ‘off-the-shelf’, cellular cardiomyoplasty strategy. Int. J. Cardiol. 117, 360–364 (2007).

    Article  PubMed  Google Scholar 

  60. Elnaggar, M. A. et al. Nitric oxide releasing coronary stent: a new approach using layer-by-layer coating and liposomal encapsulation. Small 12, 6012–6023 (2016).

    Article  CAS  PubMed  Google Scholar 

  61. Liang, X. L., Zhang, L. N., Wang, S. H., Han, Q. & Zhao, R. C. Exosomes secreted by mesenchymal stem cells promote endothelial cell angiogenesis by transferring miR-125a. J. Cell Sci. 129, 2182–2189 (2016).

    Article  CAS  PubMed  Google Scholar 

  62. Ferguson, S. W. et al. The microRNA regulatory landscape of MSC-derived exosomes: a systems view. Sci. Rep. 8, 1419 (2018).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  63. Beltrami, C. et al. Human pericardial fluid contains exosomes enriched with cardiovascular-expressed micrornas and promotes therapeutic angiogenesis. Mol. Ther. 25, 679–693 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  64. Anderson, J. D. et al. Comprehensive proteomic analysis of mesenchymal stem cell exosomes reveals modulation of angiogenesis via nuclear factor-kappa B signaling. Stem Cells 34, 601–613 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  65. Owens, G. K., Kumar, M. S. & Wamhoff, B. R. Molecular regulation of vascular smooth muscle cell differentiation in development and disease. Physiol. Rev. 84, 767–801 (2004).

    Article  CAS  PubMed  Google Scholar 

  66. Lavin, B. et al. Nitric oxide prevents aortic neointimal hyperplasia by controlling macrophage polarization. Arterioscler. Thromb. Vasc. Biol. 34, 1739–1746 (2014).

    Article  CAS  PubMed  Google Scholar 

  67. McDonald, R. A. et al. Reducing in-stent restenosis: therapeutic manipulation of mirna in vascular remodeling and inflammation. J. Am. Coll. Cardiol. 65, 2314–2327 (2015).

    Article  PubMed  PubMed Central  Google Scholar 

  68. Yan, W. et al. M2 macrophage-derived exosomes promote the c-KIT phenotype of vascular smooth muscle cells during vascular tissue repair after intravascular stent implantation. Theranostics 10, 10712–10728 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  69. Grasset, E. K. et al. Sterile inflammation in the spleen during atherosclerosis provides oxidation-specific epitopes that induce a protective B-cell response. Proc. Natl Acad. Sci. USA 112, E2030–E2038 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  70. Piccolo, R. et al. Drug-eluting or bare-metal stents for percutaneous coronary intervention: a systematic review and individual patient data meta-analysis of randomised clinical trials. Lancet 393, 2503–2510 (2019).

    Article  CAS  PubMed  Google Scholar 

  71. Alraies, M. C., Darmoch, F., Tummala, R. & Waksman, R. Diagnosis and management challenges of in-stent restenosis in coronary arteries. World J. Cardiol. 9, 640–651 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  72. Huang, P. et al. Atorvastatin enhances the therapeutic efficacy of mesenchymal stem cells-derived exosomes in acute myocardial infarction via up-regulating long non-coding RNA H19. Cardiovasc. Res. 116, 353–367 (2020).

    Article  CAS  PubMed  Google Scholar 

  73. Lim, S. Y. et al. Inflammation and delayed endothelization with overlapping drug-eluting stents in a porcine model of in-stent restenosis. Circ. J. 72, 463–468 (2008).

    Article  PubMed  Google Scholar 

  74. Liu, F. et al. Hyaluronic acid hydrogel integrated with mesenchymal stem cell-secretome to treat endometrial injury in a rat model of asherman’s syndrome. Adv. Healthc. Mater. 8, 1900411 (2019).

    Article  CAS  Google Scholar 

  75. Dinh, P. C. et al. Inhalation of lung spheroid cell secretome and exosomes promotes lung repair in pulmonary fibrosis. Nat. Commun. 11, 1064 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  76. Ozbilgin, S. et al. Renal ischemia/reperfusion injury in diabetic rats: the role of local ischemic preconditioning. Biomed. Res. Int. 2016, 8580475 (2016).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  77. Johnson, T. W. et al. Stent-based delivery of tissue inhibitor of metalloproteinase-3 adenovirus inhibits neointimal formation in porcine coronary arteries. Arterioscler. Thromb. Vasc. Biol. 25, 754–759 (2005).

    Article  CAS  PubMed  Google Scholar 

  78. Huang, C., Mei, H., Zhou, M. & Zheng, X. A novel PDGF receptor inhibitor-eluting stent attenuates in-stent neointima formation in a rabbit carotid model. Mol. Med. Rep. 15, 21–28 (2017).

    Article  CAS  PubMed  Google Scholar 

  79. Wang, Q. & Zou, M. H. Measurement of reactive oxygen species (ROS) and mitochondrial ROS in AMPK knockout mice blood vessels. Methods Mol. Biol. 1732, 507–517 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

This work was supported by grants from the National Institutes of Health (HL123920, HL137093, HL144002, HL146153, HL147357 and HL149940 to K.C.) and the American Heart Association (18TPA34230092 and 19EIA34660286 to K.C.). We thank the Analytical Instrumentation Facility at North Carolina State University (supported by the State of North Carolina and the National Science Foundation ECCS-1542015 and DMR-1726294). XPS and ToF-SIMS were performed and analysed at the Analytical Instrumentation Facility. Confocal imaging was performed at the Cellular and Molecular Imaging Facility at North Carolina State University.

Author information

Authors and Affiliations

Authors

Contributions

S.H. and K.C. designed the study and wrote the paper. Z.L. contributed to the stent modification. D.S. provided the technical and surgical support. D.Z. and K.H. contributed to the stent deployment and the hindlimb ischaemia model. Z.L., T.S., P.-U.D. and J.C. contributed to data analysis.

Corresponding author

Correspondence to Ke Cheng.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Biomedical Engineering thanks Gordana Vunjak-Novakovic and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary figures and tables.

Reporting Summary

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Hu, S., Li, Z., Shen, D. et al. Exosome-eluting stents for vascular healing after ischaemic injury. Nat Biomed Eng 5, 1174–1188 (2021). https://doi.org/10.1038/s41551-021-00705-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41551-021-00705-0

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing