Table 2. Differential expression levels of vitamin B12 pathway-encoding genes before and after bariatric surgery.
| Gene name (abbreviation) |
Gene expression by gastrointestinal segment |
Main role in B12 metabolism | ||||
|---|---|---|---|---|---|---|
| Remnant stomach | Excluded stomach | Duodenum | Jejunum | Ileum | ||
| Gastrin (GAST) | −0.044 (M) | −1.515 (M) | +0.233 (M) | −0.060 (M) | −0.077 (M) | Encodes hydrochloric acid to obtain B12 from ingested food |
| Pepsin C (PGC) | −0.069 (M) | −0.038 (M) | −0.026 (M) | −0.084 (M) | +0.115 (M) | Encodes pepsin to obtain B12 from ingested food |
| Transcobalamin I (TCN1) | −1.914 (M) | −1.985 (M) | +0.115 (M) | +0.048 (M) | +0.021 (M) | Encodes transcobalamin I to carry B12 from stomach to intestine |
| −0.132 (V) | −0.398 (V) | |||||
| Transcobalamin II (TCN2) | +0.042 (M) | +0.177 (M) | +0.045 (M) | +0.194 (M) | +0.170 (M) | Encodes transcobalamin II to carry B12 from the intestine to the blood and liver |
| +3.697 (V) | +4.079 (V) | +2.637 (V) | −0.779 (V) | +1.563 (V) | ||
| Gastric intrinsic factor (GIF) | −0.271 (M) | +0.357 (M) | −0.725 (M) | +0.112 (M) | −0.103 (M) | Encodes intrinsic factor to carry B12 through gut to ileum |
| −0.570 (V) | −0.813 (V) | |||||
| Cubilin (CUBN) | −0.184 (M) | +0.019 (M) | +0.982 (M) | +1.311 (M) | +0.685 (M) | Encodes cubilin for gut absorption of B12 |
| +7.876 (V) | +2.833 (V) | +1.925 (V) | ||||
Abbreviations: M, microarray; V, validation by real-time quantitative PCR. Negative and positive values indicate decreased and increased expression, respectively. Bold values correspond to significant changes (P≤0.05).