Multispectral and autofluorescence, human and mouse

Gastric inflammation is a major risk factor for gastric cancer. Current endoscopic methods are not capable to efficiently detect and characterize gastric inflammation, leading to a sub-optimal patients’ care. New non-invasive methods are needed. Reflectance mucosal light analysis is of particular interest in this indication. The aim of our study was to analyze the reflectance light and specific autofluorescence signals, both in humans and in a mouse model of gastritis.
We recruited patients undergoing gastroendoscopic procedure during which reflectance was analysed with a multispectral camera. In parallel, the gastritis mouse model of Helicobacter pylori infection was used to investigate reflectance from ex vivo gastric samples using a spectrometer. In both cases, autofluorescence signals were measured using a confocal microscope.
In gastritis patients, reflectance modifications were significant in near-infrared spectrum, with a decrease between 610 and 725 nm and an increase between 750 and 840 nm. Autofluorescence was also modified, showing variations around 550 nm of emission. In H. pylori infected mice developing gastric inflammatory lesions, we observed significant reflectance modifications 18 months after infection, with increased intensity between 617 and 672 nm. Autofluorescence was significantly modified after 1, 3 and 6 months around 550 and 630 nm. Both in human and in mouse, these reflectance data can be considered as biomarkers and accurately predicted inflammatory state.

胃部炎症是胃癌的主要危险因素。当前的内镜检查方法无法高效检测并定性胃部炎症，导致患者诊疗效果欠佳，因此亟需开发新型无创检测手段。黏膜反射光分析在该应用场景中具有显著研究价值。本研究旨在分析人类受试者以及胃炎小鼠模型中的黏膜反射光与特异性自体荧光信号。我们招募了接受胃镜检查的患者，使用多光谱相机（multispectral camera）对其黏膜反射光进行分析；与此同时，我们利用幽门螺杆菌（Helicobacter pylori）感染构建的胃炎小鼠模型，通过光谱仪（spectrometer）检测离体胃组织样本的反射光信号。两类实验均采用共聚焦显微镜（confocal microscope）测量自体荧光信号。胃炎患者的近红外光谱中反射光存在显著变化：610~725 nm波段反射率下降，750~840 nm波段反射率上升；自体荧光信号同样出现改变，在550 nm发射波长附近存在明显波动。在感染幽门螺杆菌并出现胃部炎性病变的小鼠中，感染18个月后可见反射光信号显著变化，617~672 nm波段信号强度升高；而在感染后1、3、6个月时，550 nm与630 nm附近的自体荧光信号均出现显著改变。无论是人类受试者还是小鼠模型，上述反射光数据均可作为生物标志物，准确预测胃部炎症状态。