Topographical Variation in Metabolic Signatures of Human Gastrointestinal Biopsies Revealed by High-Resolution Magic-Angle Spinning 1H NMR Spectroscopy

Abstract

Individual and topographical variation in the metabolic profiles of multiple human gastrointestinal tract (GIT) biopsies have been characterized using high-resolution magic-angle spinning (HRMAS) 1H NMR spectroscopy and pattern recognition. Samples from antrum, duodenum, jejunum, ileum, and transverse colon were obtained from 8 male and 8 female participants. Each gut region generated a highly characteristic metabolic profile consistent with the varying structural and functional properties of the tissue at different longitudinal levels of the gut. The antral (stomach) mucosa contained higher levels of choline, glycogen, phosphorylethanolamine, and taurine than other gut regions. The spatially close regions of the duodenum and jejunum were equivalent in terms of their gross biochemical composition with high levels of choline, glutathione, glycerophosphocholine (GPC), and lipids relative to other gut regions. The ileal mucosa showed poor discrimination from the duodenum and jejunum tissues and generated strong amino acids signatures but had relative low GPC signals. The colon (large intestine) was high in acetate, glutamate, inositols, and lactate and low in creatine, GPC, and taurine compared to the small intestine. These longitudinal metabolic variations in the human GIT could be attributed to functional variations in energy metabolism, osmoregulation, gut microbial activity, and oxidative protection. This work indicates that 1H HRMAS NMR studies may be of value in analyzing local metabolic variation due to pathological processes in gut biopsies.