Gerspach C, Imhasly S, Klingler R, Hilbe M, Hartnack S, Ruetten M
Department of Farm Animals, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, Zurich, Switzerland.
Institute of Pharmacology and Toxicology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057, Zurich, Switzerland.
BMC Vet Res. 2017 Apr 12;13(1):98. doi: 10.1186/s12917-017-1004-9.
The assessment of a liver biopsy remains the gold standard for diagnosing and staging fatty liver in dairy cows, which is often necessary for diagnostic and research purposes. Accuracy of the diagnosis relays on the quality of the biopsy, the assumed representativeness of a small tissue sample for a disease process throughout the liver and accurate human evaluation of histologic specimens. The objective of the present study was to assess the distribution of triacylglycerol (TAG) infiltration throughout the parenchyma of livers with different degrees of fatty liver in dairy cows. In addition, histopathological scores from the corresponding specimens were compared to a quantitative measurement of TAG, as well as the agreement between two observers.
Thirty livers with different degrees of lipid infiltration were selected and 10 different locations throughout the liver were assessed. The TAG content was measured enzymatically, calculated in % or mg/g wet weight, and assigned to a scoring system. Corresponding tissue specimens were stained with hematoxylin-eosin (H&E) and Oil red O (ORO) for histopathological evaluation, using a scoring system.
The difference in TAG content between any locations was less than 2%. Based on the scoring system the TAG concentration was even distributed in 79.3% of the livers. Based on kappa statistics the agreement between two pathologists and staining technique in scoring histological specimens was moderate to fair.
Overall the distribution of TAG throughout the liver and the accuracy of human evaluation of liver biopsies may lead to acceptable diagnoses for clinical purposes. Within the liver lobules a common pattern of lipid distribution depending on severity could be observed. For the staging of lipid infiltration for research projects, some degree of variation needs to be considered.
肝活检评估仍然是诊断和分期奶牛脂肪肝的金标准，这在诊断和研究目的中通常是必要的。诊断的准确性取决于活检的质量、假定的小组织样本对整个肝脏疾病过程的代表性以及对组织学标本的准确人工评估。本研究的目的是评估不同程度脂肪肝奶牛肝脏实质中三酰甘油（TAG）浸润的分布情况。此外，将相应标本的组织病理学评分与TAG的定量测量结果以及两位观察者之间的一致性进行了比较。
选择30个不同程度脂质浸润的肝脏，并评估肝脏内10个不同位置。通过酶法测量TAG含量，以湿重的百分比或毫克/克计算，并将其分配到一个评分系统中。相应的组织标本用苏木精-伊红（H&E）和油红O（ORO）染色，用于组织病理学评估，采用评分系统。
任何位置之间的TAG含量差异小于2%。根据评分系统，79.3%的肝脏中TAG浓度分布均匀。基于kappa统计，两位病理学家在对组织学标本评分以及染色技术方面的一致性为中等至一般。
总体而言，TAG在肝脏中的分布以及对肝活检的人工评估准确性可能会得出适用于临床目的的可接受诊断。在肝小叶内，可以观察到取决于严重程度的常见脂质分布模式。对于研究项目中脂质浸润的分期，需要考虑一定程度的变异性。
