Advanced Optical Imaging to Study Perinatal and Pediatric Stroke

Using two-photon microscopy and other methods to study neurovascular structure and function, including response to injury, disease, and drugs

Technology overview

Dr. Andy Shih

In the human brain, an estimated 400 miles of blood vessels deliver blood to 100 billion neurons. Dr. Andy Shih uses advanced optical imaging to study microvascular development over the lifespan, from development through aging, to understand the relationship between blood vessels and brain function, the consequences of vascular damage, and the processes and mechanisms of repair.

The Shih group has expertise in using two-photon fluorescence microscopy of the mouse and rat brain, and potentially other organs, as a real-time in vivo assay system for vascular function. Two-photon imaging, which creates angiograms using common fluorophores and fluorescent reporter proteins, has multiple advantages over methods such as confocal microscopy: The lower-energy photons penetrate tissues better, cause less damage, and give higher resolution by exciting and visualizing only tissues of interest. For studying the human brain, the Shih lab applies two-photon, confocal, and light-sheet microscopy to fixed, cleared, stained (post-mortem) tissues. These methods allow visualization of the three-dimensional architecture of the vasculature and its relationship to surrounding structures.

Two-photon imaging can be combined with laser occlusion and ablation to create precisely controlled animal models with brain microinfarcts of specific sizes, in targeted regions and vessels. These methods allow the Shih lab to observe how the structure and function of the brain vasculature and surrounding cells, including neurons, respond to stroke. The group is studying the role of pericytes, a subset of brain cells, in stroke and age-related brain diseases, development of the capillary network, and regulation of the blood-brain barrier.

Dr. Shih is interested in contributing his expertise in imaging and analysis to studies on cerebrovascular function, including using transgenic animals. He is interested in collaborating to learn how signaling pathways and regulatory molecules such as PDGF are involved in microvascular development and can be managed, for example with drugs, to direct vascular growth and repair.

Stage of Development

• Preclinical in vivo
• Advanced in vivo imaging
• Fixed tissue imaging and analysis

Partnering Opportunities

• Collaborative research opportunity
• Sponsored research agreement
• Consultation agreement

Publications

1. Berthiaume AA, Grant RI, McDowell KP, Underly RG, Hartmann DA, Levy M, Bhat NR, Shih AY. Dynamic remodeling of pericytes in vivo maintains capillary coverage in the adult mouse brain. Cell Rep. 2018;22(1):8-16.
2. Grant RI, Hartmann DA, Underly RG, Berthiaume AA, Bhat NR, Shih AY. Organizational hierarchy and structural diversity of microvascular pericytes in adult mouse cortex. J Cereb Blood Flow Metab. 2017;271678X17732229.
3. Hyacinth HI, Sugihara CL, Spencer TL, Archer DR, Shih AY. Higher prevalence of spontaneous cerebral vasculopathy and cerebral infarcts in a mouse model of sickle cell disease. J Cereb Blood Flow Metab. 2017;271678X17732275.
4. Summers PM, Hartmann DA, Hui ES, Nie X, Deardorff RL... Shih AY. Functional deficits induced by cortical microinfarcts. J Cereb Blood Flow Metab. 2017;37(11):3599-3614.
5. Underly RG, Levy M, Hartmann DA, Grant RI, Watson AN, Shih AY. Pericytes as Inducers of Rapid, Matrix metalloproteinase-9-dependent capillary damage during ischemia. J Neurosci. 2017;37(1):129-140.
6. Taylor ZJ, Hui ES, Watson AN, Nie X, Deardorff RL, Jensen JH, Helpern JA, Shih AY. Microvascular basis for growth of small infarcts following occlusion of single penetrating arterioles in mouse cortex. J Cereb Blood Flow Metab. 2016;36(8):1357-1373

Learn More

• Andy Shih, PhD