Inflammatory Response in Caco-2 Cells Stimulated with Anisakis Messengers of Pathogenicity

Abstract

Anisakis spp. third-stage larvae (L3) are the causative agents of human zoonosis called anisakiasis. The accidental ingestion of L3 can cause acute and chronic inflammation at the gastric, intestinal, or ectopic levels. Despite its relevance in public health, studies on pathogenetic mechanisms and parasite-human interplay are scarce. The aim of this study was to investigate the human inflammatory response to different Anisakis vehicles of pathogenicity. Methods: Human colorectal adenocarcinoma (Caco-2) cells were exposed to Anisakis L3 (the initial contact with the host), extracellular vesicles (EVs, Anisakis–host communication), and crude extract (CE, the larval dying). The protein quantity and gene expression of two pro-inflammatory cytokines (IL-6 and IL-8) were investigated using an ELISA test (6h and 24h) and a qReal-Time PCR (1h, 6h, and 24h), respectively. Results: The L3 and EVs induced a downregulation in both the Il-6 and Il-8 gene expression and protein quantity. On the contrary, the CE stimulated IL-6 gene expression and its protein release, not affecting IL-8. Conclusions: The Caco-2 cells seemed to not react to the exposure to the L3 and EVs, suggesting a parasite’s immunomodulating action to remain alive in an inhospitable niche. Conversely, the dying larva (CE) could induce strong activation of the immune strategy of the host that, in vivo, would lead to parasite expulsion, eosinophilia, and/or granuloma formation.

Intestinal Obstruction for Anisakiasis: Surgical and Physical Therapy Treatment

“…The most specific finding that could aid in the diagnosis is the identification of the parasite within the intestinal lumen, appearing as a filling defect with a characteristic “serpiginous” morphology. However, this finding is observed in only a few cases ( Figure 3 ) [ 18 , 20 ]. Due to the non-specific nature of the radiological findings, the differential diagnosis is broad, including conditions such as Crohn’s disease (due to location), tumors (such as adenocarcinoma, characterized by asymmetric wall thickening), and inflammatory/infectious processes.…”

“…The patient presented a subocclusive condition characterized by dilation of the proximal bowel loops and the presence of fluid and air-fluid levels. These findings were accompanied by infiltration of the mesenteric fat, subcentimeter mesenteric lymphadenopathy, and a minimal amount of free fluid in the right parietocolic leak ( Figure 1 ) [ 19 , 20 ].…”

“…A mechanical side-to-side anastomosis was performed. The surgical intervention was justified by the possibility of the existence of lymphoma and, finally, due to the obstruction and ischemia of the intestinal segment [ 19 , 20 ]. The histological examination of the resected distal ileum revealed a dense transmural eosinophilic inflammatory infiltrate extending to the serosa, as well as the presence of a parasite in the intestinal lumen with morphological characteristics consistent with Anisakis.…”

“…The histological examination of the resected distal ileum revealed a dense transmural eosinophilic inflammatory infiltrate extending to the serosa, as well as the presence of a parasite in the intestinal lumen with morphological characteristics consistent with Anisakis. These histological findings prompted a re-evaluation of the CT scan, which revealed bowel obstruction and hypodense “serpiginous” linear images within the small intestine lumen, indicative of the presence of the parasite ( Figure 3 ) [ 17 , 18 , 20 ].…”

Anisakiasis and Anisakidae

“…The findings obtained allow the authors to suggest that the parasite could exert an immunomodulatory effect that allows it to survive in the human digestive tract. At the same time, the dying larvae would induce a strong immune response, leading to the expulsion of the parasite, the generation of eosinophilia, and the formation of granulomas [ 29 ]. In the second research, the authors carried out a study of the secretome of A. simplex s.s. L3, in an attempt to identify excretion–secretion proteins involved in the host–parasite interaction, and subsequent in silico characterisation [ 30 ].…”