P0205Characterization of glycolytic metabolic reprogramming by 31P MRS for assessing intestinal fibrosis in Crohn’s Disease

Abstract Background Intestinal fibrostenosis, a disabling complication of Crohn’s disease (CD), lacks reliable early detection methods1. Glycolytic reprogramming is an early fibrotic event, providing a diagnostic target. While phosphorus MR spectroscopy (31P-MRS) enables non-invasive metabolic profiling2, we assessed 31P-MRS for quantifying this metabolic shift to detect early fibrosis. Methods In this prospective study, we enrolled a cohort of 24 CD patients who underwent MR enterography and 31P-MRS. 31P-MRS was used to measure metabolic parameters such as phosphocreatine (PCr) and pH3. All patients additionally underwent magnetization transfer imaging to calculate normalized magnetization transfer ratio (MTR) as an imaging-based reference for fibrosis. In a subset of 12 patients who subsequently underwent surgical bowel resection, we obtained intestinal specimens for histologic fibrosis scoring, and ex vivo measurements of PCr and lactic acid levels. We first validated the 31P-MRS technique by correlating spectroscopic PCr levels with ex vivo tissue PCr measurements. We then assessed its ability to characterize glycolytic reprogramming by correlating the 31P-MRS-derived pH with tissue lactic acid levels. Finally, we evaluated the clinical utility of 31P-MRS by correlating its metrics with histologic fibrosis scores and normalized MTR (normalized MTR=MTRbowel wall/MTRpsoas muscle)4. Results Our 31P-MRS measurements demonstrated robust technical and biological validity. Spectroscopic PCr levels showed a strong positive correlation with ex vivo tissue PCr measurements (r = 0.62, P=0.033). Furthermore, 31P-MRS-derived pH values were inversely correlated with tissue lactic acid levels (r = -0.64, P = 0.026), confirming its ability to detect glycolytic reprogramming, wherein lower pH reflects increased lactic acid accumulation. Crucially, these metabolic parameters were clinically relevant to intestinal fibrosis severity. 31P-MRS-derived PCr peak area exhibited significant negative correlations with both the histological fibrosis score (r = -0.66, P = 0.021) and normalized MTR (r=-0.42, P=0.041). Concordantly, PCr levels were significantly lower in moderate-severe fibrotic strictures compared to none-mild strictures (316.25 ± 67.54 vs. 462.25 ± 61.08; P=0.004). Similarly, 31P-MRS-derived pH was significantly lower in moderate-severe fibrotic strictures compared to none-mild strictures (6.95 ± 0.04 vs. 7.02 ± 0.04; P = 0.023) and normalized MTR (r = -0.51, P = 0.011), supporting the link between a glycolytic shift and fibrotic progression. Conclusion Our findings support the feasibility of 31P-MRS for detecting intestinal metabolites. As a key energy metabolite, PCr may reflect energy reprogramming during intestinal fibrogenesis. References: 1. Rieder F, Latella G, Magro F, et al. European Crohn’s and Colitis Organisation Topical Review on Prediction, Diagnosis and Management of Fibrostenosing Crohn’s Disease. J Crohns Colitis. 2016;10(8):873-885. doi:10.1093/ecco-jcc/jjw0552. 2. Traussnigg S, Kienbacher C, Gajdošík M, et al. Ultra-high-field magnetic resonance spectroscopy in non-alcoholic fatty liver disease: Novel mechanistic and diagnostic insights of energy metabolism in non-alcoholic steatohepatitis and advanced fibrosis. Liver International. 2017;37(10):1544-1553. doi:10.1111/liv.134513. 3. Abrigo JM, Shen J, Wong VWS, et al. Non-alcoholic fatty liver disease: spectral patterns observed from an in vivo phosphorus magnetic resonance spectroscopy study. J Hepatol. 2014;60(4):809-815. doi:10.1016/j.jhep.2013.11.0184. 4. Li XH, Mao R, Huang SY, et al. Characterization of Degree of Intestinal Fibrosis in Patients with Crohn Disease by Using Magnetization Transfer MR Imaging. Radiology. 2018;287(2):494-503. doi:10.1148/radiol.2017171221 Conflict of interest: Mr. Zheng, Weikai: No conflict of interest Wu, Luyao: No conflict of interest Wang, Yangdi: No conflict of interest Zhao, Qiaochu: No conflict of interest Zhang, Ruonan: No conflict of interest Gao, Yunyu: No conflict of interest Mao, Ren: No conflict of interest Chen, Minhu: No conflict of interest Feng, Shi-ting: No conflict of interest Li, Xuehua: No conflict of interest