Theranostic porphyrin nanoparticles identify atherosclerosis via multimodal imaging and elicit atheroprotective effects

Victoria A Nankivell; Lauren Sandeman; Liam Stretton; Achini K Vidanapathirana; Maneesha A Rajora; Juan Chen; William Tieu; Hanyi Weng; Maaike Kockx; Leonard Kritharides; Peter J Psaltis; Joanne T M Tan; Yung-Chih Chen; Karlheinz Peter; Gang Zheng; Christina A Bursill

doi:10.1016/j.mtbio.2025.102202

Theranostic porphyrin nanoparticles identify atherosclerosis via multimodal imaging and elicit atheroprotective effects

Mater Today Bio. 2025 Aug 21:34:102202. doi: 10.1016/j.mtbio.2025.102202. eCollection 2025 Oct.

Authors

Victoria A Nankivell^{1

2

3}, Lauren Sandeman^{1

3}, Liam Stretton^{1

3}, Achini K Vidanapathirana^{1

2

3}, Maneesha A Rajora^{4

5}, Juan Chen^{4

5}, William Tieu¹, Hanyi Weng^{4

5}, Maaike Kockx⁶, Leonard Kritharides^{6

7}, Peter J Psaltis^{1

2

3}, Joanne T M Tan^{1

3}, Yung-Chih Chen⁸, Karlheinz Peter⁸, Gang Zheng^{4

5}, Christina A Bursill^{1

2

3}

Affiliations

¹ Vascular Research Centre, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, 5000, Australia.
² Australian Research Council (ARC) Centre of Excellence for Nanoscale BioPhotonics (CNBP), Australia.
³ Faculty of Health and Medical Science, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, 5000, Australia.
⁴ Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, M5G 1L7, Canada.
⁵ Department of Medical Biophysics, University of Toronto, Ontario, M5G 1L7, Canada.
⁶ ANZAC Research Institute, Concord Repatriation General Hospital, Sydney Local Health District and University of Sydney, Australia.
⁷ Department of Cardiology, Concord Repatriation General Hospital, Sydney Local Health District and University of Sydney, Australia.
⁸ Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.

Abstract

Background: Porphyrin-lipid nanoparticles (Por-NPs) have unrealized potential for atherosclerosis. Por-NPs incorporate porphyrin-lipid which permits fluorescence imaging and chelates Copper-64 (⁶⁴Cu) for positron emission tomography (PET) imaging. Their outer shell contains a short peptide 'R4F' that enables macrophage targeting and therapeutic effects. Accordingly, this study investigates the simultaneous diagnostic and therapeutic properties of Por-NPs in atherosclerosis.

Results: In vitro, Por-NPs were found to be internalized by immortalised bone marrow-derived macrophages (iBMDMs), visualized via fluorescence microscopy and flow cytometry. Por-NPs also increased cholesterol efflux from [³H]-cholesterol-loaded iBMDMs, (49 %, P < 0.05). Incubation of iBMDMs with Por-NPs reduced mRNA levels of inflammatory mediators Il1b (88 %), Il18 (54 %) Ccl5 (75 %) and Ccl17 (92 %), and protein secretion of IL-1β (69 %), CCL5 (82 %) and CCL17 (94 %), P < 0.05. Por-NPs suppressed inflammasome components Nlrp3 (69 %) and Asc (36 %), P < 0.05. Studies using siRNA deletion of SR-B1 and methyl-β-cyclodextrin, revealed the anti-inflammatory properties of Por-NPs were independent of SR-B1 and cholesterol efflux. However, Por-NPs suppressed activation of inflammatory transcription factor NF-κB (53 %, P < 0.05). In vivo, in Apoe ^-/- mice, serial non-invasive PET imaging showed ⁶⁴Cu-labelled Por-NPs localised in hearts and detected increases in plaque size longitudinally with high-cholesterol diet. Por-NP fluorescence was visualized in aortic sinus plaques, co-localised with CD68⁺ macrophages, and by fluorescence IVIS imaging in aortic arch plaque. In two murine models, Por-NP-treated mice had smaller early-stage (22 %) and unstable plaques (52 %). Por-NP-treated mice had fewer circulating (32 %) and aortic (81 %) monocytes, and lower mRNA levels of aortic arch Rela (26 %) and Nfkb1 (27 %), P < 0.05.

Conclusions: Por-NPs detect plaques using multiple imaging modalities and exhibit atheroprotective effects, presenting as novel nanoscale theranostics for atherosclerosis.

Keywords: Anti-inflammatory; Imaging atherosclerosis; Lipid-based nanoparticles; Multimodal imaging; Porphyrin-lipid.