FI nanoparticles enhanced multimodal near-infrared photoacoustic microscopy and optical coherence tomography imaging of rat choroid

Differential artery–vein analysis is valuable for early detection of diabetic retinopathy and other eye diseases. As a new optical coherence tomography imaging modality, optical coherence tomography angiography provides capillary level resolution for accurate examination of retinal vasculatures. However, differential artery–vein analysis in optical coherence tomography angiography particularly for macular region in which blood vessels are small is challenging. In coordination with an automatic vessel tracking algorithm, we report here the feasibility of using near infrared optical coherence tomography oximetry to guide artery–vein classification in optical coherence tomography angiography of macular region. Impact statement It is known that arteries and veins can be affected by retinal diseases differently. Therefore, quantitative artery–vein analysis holds the promise for better disease detection and treatment evaluation. However, clinical optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) instruments lack the function of differential artery–vein analysis. Here, we report the feasibility of near infrared OCT oximetry-guided artery–vein classification in OCTA. Because the OCT and OCTA are naturally captured from the same instrument simultaneously, the presented method is feasible for practical deployment of differential artery–vein analysis in OCTA.

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Highly Selective PPARα (Peroxisome Proliferator‐Activated Receptor α) Agonist Pemafibrate Inhibits Stent Inflammation and Restenosis Assessed by Multimodality Molecular‐Microstructural Imaging

Journal of the American Heart Association ◽

10.1161/jaha.121.020834 ◽

2021 ◽

Author(s):

Hiroshi Iwata ◽

Eric A. Osborn ◽

Giovanni J. Ughi ◽

Kentaro Murakami ◽

Claudia Goettsch ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Near Infrared ◽

Neointimal Hyperplasia ◽

Coronary Stent ◽

Peroxisome Proliferator ◽

Optical Coherence ◽

Peroxisome Proliferator Activated Receptor ◽

Near Infrared Fluorescence ◽

Tomography Imaging ◽

Optical Coherence Tomography Imaging

BACKGROUND New pharmacological approaches are needed to prevent stent restenosis. This study tested the hypothesis that pemafibrate, a novel clinical selective PPARα (peroxisome proliferator‐activated receptor α) agonist, suppresses coronary stent‐induced arterial inflammation and neointimal hyperplasia. METHODS AND RESULTS Yorkshire pigs randomly received either oral pemafibrate (30 mg/day; n=6) or control vehicle (n=7) for 7 days, followed by coronary arterial implantation of 3.5 × 12 mm bare metal stents (2–4 per animal; 44 stents total). On day 7, intracoronary molecular‐structural near‐infrared fluorescence and optical coherence tomography imaging was performed to assess the arterial inflammatory response, demonstrating that pemafibrate reduced stent‐induced inflammatory protease activity (near‐infrared fluorescence target‐to‐background ratio: pemafibrate, median [25th‐75th percentile]: 2.8 [2.5–3.3] versus control, 4.1 [3.3–4.3], P =0.02). At day 28, animals underwent repeat near‐infrared fluorescence–optical coherence tomography imaging and were euthanized, and coronary stent tissue molecular and histological analyses. Day 28 optical coherence tomography imaging showed that pemafibrate significantly reduced stent neointima volume (pemafibrate, 43.1 [33.7–54.1] mm 3 versus control, 54.2 [41.2–81.1] mm 3 ; P =0.03). In addition, pemafibrate suppressed day 28 stent‐induced cellular inflammation and neointima expression of the inflammatory mediators TNF‐α (tumor necrosis factor‐α) and MMP‐9 (matrix metalloproteinase 9) and enhanced the smooth muscle differentiation markers calponin and smoothelin. In vitro assays indicated that the STAT3 (signal transducer and activator of transcription 3)–myocardin axes mediated the inhibitory effects of pemafibrate on smooth muscle cell proliferation. CONCLUSIONS Pemafibrate reduces preclinical coronary stent inflammation and neointimal hyperplasia following bare metal stent deployment. These results motivate further trials evaluating pemafibrate as a new strategy to prevent clinical stent restenosis.

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