Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
Vet Res. 2023 Apr 13;54(1):34. doi: 10.1186/s13567-023-01169-7.
Porcine enteric viral infections cause high morbidity and mortality in young piglets (<3 weeks). Later, these rates decrease with age. This age-dependent infectivity remains largely unexplored. This study investigated the changes in intestinal morphology, number of mucus-producing cells and expression level of coronavirus receptors in three age groups of pigs. Villus height and crypt depth increased with age from 3 days to 3 months in duodenum and ileum but not in mid-jejunum, where the villus height decreased from 580 µm at 3 days to 430 µm at 3 months. Enterocyte length-to-width ratio increased from 3 days to 3 months in all intestinal regions. The number of mucus-producing cells increased with age in the intestinal villi and crypts. The Brunner's glands of the duodenum contained the highest concentration of mucus-producing cells. The expression of coronavirus receptor APN was highest in the small intestinal villi at all ages. DPP4 expression slightly decreased over time in jejunum and ileum; it was highest in the ileal villi of 3-day-old piglets (70.2% of cells). ACE2 and TMPRSS2 positive cells increased with age in jejunal and ileal crypts and were particularly dominant in the ileal crypts (> 45% of cells). Except for the expression of DPP4 in the jejunum and ileum of young pigs, the expression pattern of the selected coronavirus receptors was very different and not correlated with the age-dependent susceptibility to viral infections. In contrast, the number of mucus-producing cells increased over time and may play an essential role in protecting enteric mucosae against intestinal viruses.
猪肠道病毒感染会导致仔猪（<3 周龄）的高发病率和死亡率。随着年龄的增长，这些比率会下降。这种年龄依赖性的传染性在很大程度上仍未得到探索。本研究调查了三个年龄段猪肠道形态、黏液细胞数量和冠状病毒受体表达水平的变化。十二指肠和回肠的绒毛高度和隐窝深度随年龄从 3 天增加到 3 个月，但在中肠没有增加，中肠的绒毛高度从 3 天的 580µm 下降到 3 个月的 430µm。肠细胞的长径与宽径比在所有肠段都随年龄从 3 天增加到 3 个月。黏液细胞数量在肠绒毛和隐窝中随年龄增加。十二指肠的 Brunner 腺含有最多的黏液细胞。冠状病毒受体 APN 的表达在所有年龄段的小肠绒毛中最高。DPP4 在空肠和回肠中的表达随时间略有下降；在 3 日龄仔猪的回肠绒毛中表达最高（70.2%的细胞）。ACE2 和 TMPRSS2 阳性细胞在空肠和回肠隐窝中随年龄增加，在回肠隐窝中尤为突出（>45%的细胞）。除了幼猪空肠和回肠中 DPP4 的表达外，所选冠状病毒受体的表达模式差异很大，与病毒感染的年龄依赖性易感性无关。相比之下，黏液细胞数量随时间增加，可能在保护肠道黏膜免受肠道病毒感染方面发挥重要作用。
