Heilmann Romy M, Nestler Jasmin, Schwarz Jutta, Grützner Niels, Ambrus Andy, Seeger Johannes, Suchodolski Jan S, Steiner Jörg M, Gurtner Corinne
Department for Small Animals, College of Veterinary Medicine, University of Leipzig, Leipzig, SN, Germany.
Department for Small Animals, College of Veterinary Medicine, University of Leipzig, Leipzig, SN, Germany.
Vet Immunol Immunopathol. 2019 May;211:64-74. doi: 10.1016/j.vetimm.2019.04.003. Epub 2019 May 6.
S100A12 and S100A8/A9 (calprotectin) are released from activated mononuclear cells and belong to the group of damage associated molecular patterns. Fecal S100A12 and S100A8/A9 concentrations have been suggested as biomarkers of intestinal inflammation in dogs with chronic inflammatory enteropathies (CIE). However, the mucosal cellular infiltrate in dogs with CIE is primarily lymphocytic-plasmacytic. Whether fecal S100A12 and S100A8/A9 levels reflect the number and/or activity of intestinal mucosal mononuclear cells, or whether these proteins are also produced by other cells has not been investigated. Thus, the aim of this study was to evaluate intestinal mucosal S100A12 and S100A8/A9 positivity and a potential relationship with the respective protein concentrations in serum and fecal samples in dogs with CIE. Serum (single sample), fecal samples (from 3 consecutive days), and gastrointestinal tissue biopsies (i.e., stomach, duodenum, ileum, and colon) were evaluated from 21 dogs with CIE. Serum and fecal S100A12 and S100A8/A9 concentrations were measured by analytically validated in-house ELISAs. Tissue biopsies underwent routine histopathology and immunohistochemical evaluation for S100A12 and S100A8/A9 positivity (S100A12 and S100A8/A9, each recorded as positive cells/mm). S100A12 and S100A8/A9 cells were identified in all segments of the gastrointestinal tract, but were predominantly localized in the lamina propria (LP). Duodenal LP S100A12 positivity correlated statistically significantly with that in the stomach and ileum (ρ = 0.66 and 0.69, both p < 0.01), but was inversely correlated with the severity of macrophage infiltration in the duodenum (ρ=-0.47, p = 0.042). Ileal LP S100A8/A9 positivity correlated positively with the extent of ileal neutrophil and macrophage infiltration (ρ=0.61, p = 0.047). Fecal S100A12 concentrations strongly correlated with the number of S100A12 cells along the entire gastrointestinal tract (ρ = 0.76, p = 0.028), whereas serum S100A12 concentrations were inversely correlated to colonic S100A12 cell counts (ρ=-0.50, p = 0.043). Mucosal S100A8/A9 cell counts were not associated with the corresponding fecal or serum S100A8/A9 concentrations. These results suggest that the intestinal mucosa in dogs with CIE contains an increased number of activated (pro-inflammatory) phagocytes expressing and secreting the S100A12 protein, but the macrophage population seen on routine histopathology is predominantly mature (anti-inflammatory) with a reduced or absent expression of S100A12 and a normal or increased expression of S100A8/A9. However, the distribution of intestinal S100A8/A9 expression requires further study.
S100A12和S100A8/A9（钙卫蛋白）由活化的单核细胞释放，属于损伤相关分子模式组。粪便中S100A12和S100A8/A9的浓度已被提议作为慢性炎症性肠病（CIE）犬肠道炎症的生物标志物。然而，CIE犬的黏膜细胞浸润主要是淋巴细胞-浆细胞性的。粪便中S100A12和S100A8/A9水平是否反映肠道黏膜单核细胞的数量和/或活性，或者这些蛋白质是否也由其他细胞产生尚未得到研究。因此，本研究的目的是评估CIE犬肠道黏膜中S100A12和S100A8/A9的阳性情况以及与血清和粪便样本中相应蛋白质浓度的潜在关系。对21只CIE犬的血清（单个样本）、粪便样本（连续3天）和胃肠道组织活检样本（即胃、十二指肠、回肠和结肠）进行了评估。通过经过分析验证的内部酶联免疫吸附测定（ELISA）法测量血清和粪便中S100A12和S100A8/A9的浓度。对组织活检样本进行常规组织病理学检查以及针对S100A12和S100A8/A9阳性情况的免疫组织化学评估（S100A12和S100A8/A9，均记录为阳性细胞/mm）。在胃肠道的所有节段均发现了S100A12和S100A8/A9细胞，但主要位于固有层（LP）。十二指肠LP中S100A12的阳性情况与胃和回肠中的阳性情况在统计学上显著相关（ρ分别为0.66和0.69，均p<0.01），但与十二指肠中巨噬细胞浸润的严重程度呈负相关（ρ=-0.47，p=0.042）。回肠LP中S100A8/A9的阳性情况与回肠中嗜中性粒细胞和巨噬细胞浸润的程度呈正相关（ρ=0.61，p=0.047）。粪便中S100A12的浓度与整个胃肠道中S100A12细胞的数量密切相关（ρ=0.76，p=0.028），而血清中S100A12的浓度与结肠中S100A12细胞计数呈负相关（ρ=-0.50，p=0.043）。黏膜中S100A8/A9细胞计数与相应的粪便或血清中S100A8/A9浓度无关。这些结果表明，CIE犬的肠道黏膜中表达和分泌S100A12蛋白的活化（促炎）吞噬细胞数量增加，但常规组织病理学中所见的巨噬细胞群体主要是成熟的（抗炎），S100A12表达减少或缺失，S100A8/A9表达正常或增加。然而，肠道S100A8/A9表达的分布情况需要进一步研究。
