Cheheltani Rabee, McGoverin Cushla M, Rao Jayashree, Vorp David A, Kiani Mohammad F, Pleshko Nancy
Department of Mechanical Engineering, Temple University, Philadelphia, PA 19122, USA.
Analyst. 2014 Jun 21;139(12):3039-47. doi: 10.1039/c3an02371k. Epub 2014 Apr 24.
Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues.
细胞外基质(ECM)是包括主动脉在内的许多生物组织的关键组成部分和调节因子。几种主动脉病变与基质组成的显著变化有关,特别是主动脉结构蛋白、胶原蛋白和弹性蛋白的含量、质量和类型。本研究的目的是开发一种与生化分析相当的红外光谱方法,用于定量主动脉中的胶原蛋白和弹性蛋白。酶降解的猪主动脉样本被用作腹主动脉瘤(AAA)中ECM降解的模型。酶处理后,通过红外光纤探头(IFOP)和傅里叶变换红外成像光谱(FT-IRIS)获取主动脉组织的傅里叶变换红外(FTIR)光谱。对胶原蛋白和弹性蛋白含量进行生化定量,并建立偏最小二乘(PLS)模型,基于FTIR光谱预测主动脉中的胶原蛋白和弹性蛋白含量。从FT-IRIS光谱建立的PLS模型能够以强相关性预测样本中的弹性蛋白和胶原蛋白含量(验证的均方根误差分别为范围的8.4%和11.1%),并且IFOP光谱成功用于预测弹性蛋白含量(均方根误差为范围的11.3%)。FT-IRIS模型的PLS回归系数用于在降解的猪主动脉组织以及人类AAA活检组织的切片中绘制胶原蛋白和弹性蛋白的图谱,与组织学相比,创建了每个成分的类似图谱。这些结果支持FTIR光谱技术在AAA组织评估中的进一步应用。