What could explain why ileal ASBT protein expression in CIE dogs correlated inversely with histopath scores?

• A. Inflammatory cytokines inhibit ASBT gene expression
• B. Inflammation increases ASBT protein synthesis
• C. Increased mucosal transporters due to inflammation
• D. ASBT protein is not affected by inflammation

Answer: (A)

Inflammatory mediators can downregulate intestinal transporters. In the ileum, the ASBT transporter is responsible for reabsorbing bile acids, and its expression is sensitive to the mucosal cytokine environment. In dogs with chronic inflammatory enteropathy, higher histopathology scores reflect more severe inflammation, which is associated with increased levels of pro‑inflammatory cytokines. These cytokines can suppress ASBT gene expression, leading to lower transcription, reduced protein synthesis, and sometimes altered trafficking or degradation of the transporter. Therefore, as histologic inflammation worsens, ASBT protein expression tends to fall, producing an inverse correlation. The idea that inflammation would increase ASBT, or that ASBT is unaffected, contradicts the observed relationship and the known inhibitory effects of cytokines on transporter expression.