Background
Behçet’s disease (BD) is a recurrent multisystem inflammatory disease. Anti-tumor necrosis factor (TNF) α agents have been used to treat patients with intestinal BD with severe disease activity or those who are resistant to conventional treatments; however, the long-term efficacy of anti-TNFα agents in intestinal BD remains unclear. In the present study, we investigated the clinical outcomes and predictors of discontinuation of anti-TNFα agents in patients with intestinal BD.
Methods
We reviewed the medical records of patients with intestinal BD who received first-line anti-TNFα agents between January 2009 and June 2020. The primary outcome was the percentage of patients who continued anti-TNFα therapy for 48 weeks. Secondary outcomes included the percentage of patients who achieved marked improvement, complete remission, and mucosal healing, as well as predictors of discontinuation of anti-TNFα agents.
Results
A total of 29 patients were included in the study. Twenty-two (75.9%) patients continued anti-TNFα therapy for 48 weeks. The percentage of patients who achieved marked improvement, complete remission, and mucosal healing at week 48 was 48.3%, 37.9%, and 48.3%, respectively. At week 96, 11 (37.9%) patients achieved marked improvement, complete remission, and mucosal healing. A higher C-reactive protein level (CRP; ≥ 1 mg/dL) at baseline was a predictor of discontinuation of anti-TNFα agents.
Conclusions
The 48-week continuation rate of anti-TNFα agents was 75.9% in bio-naïve patients with intestinal BD. However, a higher baseline CRP level (≥ 1 mg/dL) was associated with discontinuation of anti-TNFα agents.
Background
Amino acid transporters play an important role in supplying nutrition to cells and are associated with cell proliferation. L-type amino acid transporter 1 (LAT1) is highly expressed in many types of cancers and promotes tumor growth; however, how LAT1 affects tumor development is not fully understood.
Methods
To investigate the role of LAT1 in intestinal tumorigenesis, mice carrying LAT1 floxed alleles that also expressed Cre recombinase from the promoter of gene encoding Villin were crossed to an ApcMin/+ background (LAT1fl/fl; vil-cre; ApcMin/+), which were subject to analysis; organoids derived from those mice were also analyzed.
Results
This study showed that LAT1 was constitutively expressed in normal crypt base cells, and its conditional deletion in the intestinal epithelium resulted in fewer Paneth cells. LAT1 deletion reduced tumor size and number in the small intestine of ApcMin/+ mice. Organoids derived from LAT1-deleted ApcMin/+ intestinal crypts displayed fewer spherical organoids with reduced Wnt/β-catenin target gene expression, suggesting a low tumor-initiation capacity. Wnt3 expression was decreased in the absence of LAT1 in the intestinal epithelium, suggesting that loss of Paneth cells due to LAT1 deficiency reduced the risk of tumor initiation by decreasing Wnt3 production.
Conclusions
LAT1 affects intestinal tumor development in a cell-extrinsic manner through reduced Wnt3 expression in Paneth cells. Our findings may partly explain how nutrient availability can affect the risk of tumor development in the intestines.
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