Evans Blue Dye: A Revisit of Its Applications in Biomedicine

Abstract

Evans blue (EB) dye has owned a long history as a biological dye and diagnostic agent since its first staining application by Herbert McLean Evans in 1914. Due to its high water solubility and slow excretion, as well as its tight binding to serum albumin, EB has been widely used in biomedicine, including its use in estimating blood volume and vascular permeability, detecting lymph nodes, and localizing the tumor lesions. Recently, a series of EB derivatives have been labeled with PET isotopes and can be used as theranostics with a broad potential due to their improved half-life in the blood and reduced release. Some of EB derivatives have even been used in translational applications in clinics. In addition, a novel necrosis-avid feature of EB has recently been reported in some preclinical animal studies. Given all these interesting and important advances in EB study, a comprehensive revisiting of EB has been made in its biomedical applications in the review.

Figure 1

Evaluation of myocardial infarction core (MI-core), area at risk (AAR), and salvageable zone (SZ) in a rabbit with reperfused MI by in vivo and ex vivo imaging techniques and dynamic imaging quantification [32]. (a) Delayed, enhanced cardiac magnetic resonance imaging displays the MI-core as a transmural hyperenhanced area involving anterior papillary muscle; (b) T2-weighted imaging shows an extensive hyperintense region in the anterolateral wall; (c) digital radiograph of the red iodized oil-stained heart section shows a filling defect with few collateral vessels in the anterolateral wall in contrast to the rest of opaque left ventricle; (d) photograph of the heart section stained by multifunctional staining depicts the MI-core as an Evans blue dye-stained blue lesion simulating what is seen in (a) and shows the normal ventricular wall in red leaving the AAR (including the blue MI-core) unstained, which perfectly matches with the AAR in (c) and whitish zones which are suggestive of the SZ; (e) photomacroscopy of HE-stained heart slice views the MI-core as a hemorrhagic infarct similar in size to the blue lesion in (f); (f) photomicroscopy (×100) of HE-stained heart slice confirms the presence of the AAR (necrotic MI-core plus the viable but inflammatory SZ) and remote normal myocardium (NM) (reprinted and modified with permission from Feng Y, Chen F, Ma Z, Dekeyzer F, Yu J, Xie Y, Cona MM, Oyen R, Ni Y. Theranostics. 2013, 4: 24–35).

Figure 2

Postmortem analysis of necrotic and viable liver from rats with reperfused partial liver infarction that received iodine-123-labeled monoiodohypericin followed by the necrosis-avid dye, Evans blue [33]. At 4, 24, and 48 hours (h) after radioactivity injection, liver necrosis is outlined by the Evans blue as a blue region (A1, B1, and C1), with viable liver without staining (A1′, B1′, and C1′). Autoradiograms of 50 μm thick sections show higher tracer accumulation in the hepatic infarction (A2, B2, and C2) than in viable liver (A2′, B2′, and C2′). The color code bar represents the coding scheme for the radioactivity. On histologic sections, the presence of scattered liver necrosis (A3, B3, and C3) and the location of the normal liver (A3′, B3′, and C3′) are confirmed (reprinted and modified with permission from Miranda Cona M, Koole M, Feng Y, Liu Y, Verbruggen A, Oyen R, Ni Y. International Journal of Oncology 2014, 44: 819–829).