Noninvasive in vivo quantification of adeno-associated virus serotype 9–mediated expression of the sodium/iodide symporter under hindlimb ischemia and neuraminidase desialylation in skeletal muscle using single-photon emission computed tomography/computed tomography

Nabil E. Boutagy, Silvia Ravera, Xenophon Papademetris, John A. Onofrey, Zhen W. Zhuang, Jing Wu, Attila Feher, Mitchel R. Stacy, Brent A. French, Brian H. Annex, Nancy Carrasco, Albert J. Sinusas

Research output: Contribution to journalEditorial

1 Scopus citations

Abstract

BACKGROUND: We propose micro single-photon emission computed tomography/computed tomography imaging of the hNIS (human sodium/ iodide symporter) to noninvasively quantify adeno-associated virus 9 (AAV9)-mediated gene expression in a murine model of peripheral artery disease. METHODS: AAV9-hNIS (2×1011 viral genome particles) was injected into nonischemic or ischemic gastrocnemius muscles of C57Bl/6J mice following unilateral hindlimb ischemia ± the α-sialidase NA (neuraminidase). Control nonischemic limbs were injected with phosphate buffered saline or remained noninjected. Twelve mice underwent micro single-photon emission computed tomography/computed tomography imaging after serial injection of pertechnetate (99mTcO4), a NIS substrate, up to 28 days after AAV9-hNIS injection. Twenty four animals were euthanized at selected times over 1 month for ex vivo validation. Forty-two animals were imaged with 99mTcO4 ± the selective NIS inhibitor perchlorate on day 10, to ascertain specificity of radiotracer uptake. Tissue was harvested for ex vivo validation. A modified version of the U-Net deep learning algorithm was used for image quantification. RESULTS: As quantitated by standardized uptake value, there was a gradual temporal increase in 99mTcO4 uptake in muscles treated with AAV9-hNIS. Hindlimb ischemia, NA, and hindlimb ischemia plus NA increased the magnitude of 99mTcO4 uptake by 4- to 5-fold compared with nonischemic muscle treated with only AAV9-hNIS. Perchlorate treatment significantly reduced 99mTcO4 uptake in AAV9-hNIS-treated muscles, demonstrating uptake specificity. The imaging results correlated well with ex vivo well counting (r2=0.9375; P<0.0001) and immunoblot analysis of NIS protein (r2=0.65; P<0.0001). CONCLUSIONS: Micro single-photon emission computed tomography/ computed tomography imaging of hNIS-mediated 99mTcO4 uptake allows for accurate in vivo quantification of AAV9-driven gene expression, which increases under ischemic conditions or neuraminidase desialylation in skeletal muscle.

Original languageEnglish (US)
Article numbere009063
JournalCirculation: Cardiovascular Imaging
Volume12
Issue number7
DOIs
StatePublished - Jul 1 2019
Externally publishedYes

Keywords

  • Animals
  • Emission computed
  • Genetic therapy
  • Neuraminidase
  • Peripheral artery disease
  • Single-photon
  • Tomography

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine

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