Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA.
Gut. 2013 Mar;62(3):395-403. doi: 10.1136/gutjnl-2011-301913. Epub 2012 Mar 17.
To demonstrate a near-infrared (NIR) peptide that is highly specific for colonic adenomas on fluorescence endoscopy in vivo.
A 3 mm diameter endoscope was adapted to deliver 671 nm illumination and collect NIR fluorescence (696-736 nm). Target (QPIHPNNM) and control (YTTNKH) peptides were labelled with Cy5.5, a NIR dye, and characterised by mass spectra. The peptides were topically administered separately (100 μM) through the endoscope's instrument channel into the distal colon of CPC;Apc mice, genetically engineered to spontaneously develop adenomas. After 5 min for incubation, the unbound peptides were rinsed off, and images were collected at a rate of 10 frames/s. Regions of interest were identified around the adenoma and adjacent normal-appearing mucosa on white light. Intensity measurements were made from these same regions on fluorescence, and the target-to-background ratio (TBR) was calculated.
An image resolution of 9.8 μm and field of view of 3.6 mm was achieved at a distance of 2.5 mm between the distal end of the instrument and the tissue surface. On mass spectra, the experimental mass-to-charge ratio for the Cy5.5-labelled target and control peptides agreed with expected values. The NIR fluorescence images of adenomas revealed individual dysplastic crypts with distorted morphology. By comparison, only amorphous surface features could be visualised from reflected NIR light. The average TBR for adenomas was found to be 3.42 ± 1.30 and 1.88 ± 0.38 for the target and control peptides, respectively, p=0.007.
A NIR peptide was shown to be highly specific for colonic adenomas on fluorescence endoscopy in vivo and to achieve sub-cellular resolution images.
展示一种近红外（NIR）肽，该肽在体内荧光内窥镜下对结肠腺瘤具有高度特异性。
将直径为 3 毫米的内窥镜改装为可提供 671nm 照明并收集近红外荧光（696-736nm）。目标（QPIHPNNM）和对照（YTTNKH）肽用近红外染料 Cy5.5 标记，并通过质谱进行表征。这些肽通过内窥镜的器械通道单独（100μM）局部施用于 CPC；Apc 小鼠，这些小鼠经过基因工程改造，可自发形成腺瘤。孵育 5 分钟后，洗掉未结合的肽，以 10 帧/秒的速度采集图像。在白光下，在腺瘤及其周围正常外观的粘膜周围识别感兴趣区域。从这些相同的荧光区域进行强度测量，并计算目标与背景的比值（TBR）。
在器械末端与组织表面之间距离为 2.5mm 时，实现了 9.8μm 的图像分辨率和 3.6mm 的视场。在质谱上，Cy5.5 标记的目标和对照肽的实验质荷比与预期值一致。腺瘤的近红外荧光图像显示出形态扭曲的单个发育不良隐窝。相比之下，只能从反射的近红外光中观察到无定形的表面特征。发现腺瘤的平均 TBR 分别为 3.42±1.30 和 1.88±0.38，用于目标和对照肽，p=0.007。
在体内荧光内窥镜下，近红外肽被证明对结肠腺瘤具有高度特异性，并实现了亚细胞分辨率的图像。
