Feasibility of 125I-RGD uptake as a marker of angiogenesis after myocardial infarction

Ann Nucl Med. 2022 Mar;36(3):235-243. doi: 10.1007/s12149-021-01695-4. Epub 2021 Nov 26.

Abstract

Objective: Angiogenesis is an important process facilitating the healing process after myocardial infarction. 125I-RGD imaging may be a promising candidate to image angiogenesis but may also detect inflammation.

Methods: Left coronary artery was occluded for 30 min, followed by reperfusion in a rat model (n = 31). One, 3, 7 and 14 days, 1 and 2 months later, Triple-tracer autoradiography was performed. 125I-RGD (1.5 MBq) and 201Tl (15 MBq) were injected at 80 and 10 min before sacrifice. Left coronary artery was reoccluded and 99mTc-MIBI (150-180 MBq) was injected 1 min before sacrifice to verify the area at risk. Angiogenesis and macrophage infiltration were evaluated by immunohistochemical analysis with anti-alpha-smooth muscle actin and anti-CD68, respectively.

Results: 125I-RGD uptake ratio in the area at risk was weak at day 3 (1.23 ± 0.23 but increased markedly and peaked at day 7 (2.27 ± 0.37) followed by a gradual reduction until 1 and 2 months later (1.93 ± 0.16 at 1 month, 1.58 ± 0.15 at 2 month). In the immunohistochemical analysis, copious staining of anti-CD68 cells was observed, with anti-SMA cells stained only minimally at day 3. The number of anti-CD68 cells was decreased significantly at day 7 but largely absent at 1 month. Anti-SMA positive cells peaked at day 7 and reduced gradually until 1 month.

Conclusions: Myocardial 125I-RGD uptake reflects angiogenesis rather than inflammation after myocardial infarction.

Keywords: Angiogenesis; Macrophage; Myocardial infarction; RGD; αvβ3 integrin.

MeSH terms

  • Animals
  • Feasibility Studies
  • Humans
  • Integrin alphaVbeta3*
  • Iodine Radioisotopes
  • Myocardial Infarction* / diagnostic imaging
  • Oligopeptides
  • Radiopharmaceuticals
  • Rats

Substances

  • Integrin alphaVbeta3
  • Iodine Radioisotopes
  • Oligopeptides
  • Radiopharmaceuticals
  • Iodine-125