Wilk Benjamin, Smailovic Haris, Sullivan Rebecca, Sistermans Erik R, Butler John, Jago Hannah, Kovacs Michael, Wisenberg Gerald, Thiessen Jonathan D, Prato Frank S
Department of Imaging, Lawson Health Research Institute, 268 Grosvenor St., London, ON, N6A 4V2, Canada.
Medical Biophysics, Western University, London, ON, Canada.
EJNMMI Res. 2023 Oct 12;13(1):90. doi: 10.1186/s13550-023-01040-y.
After myocardial infarction, fibrosis and an ongoing dysregulated inflammatory response have been shown to lead to adverse cardiac remodeling. FDG PET is an imaging modality sensitive to inflammation as long as suppression protocols are observed while gadolinium enhanced MRI can be used to determine extracellular volume (ECV), a measure of fibrosis. In patients, glucose suppression is achieved variously through a high fat diet, fasting and injection of heparin. To emulate this process in canines, a heparin injection and lipid infusion are used, leading to similar fatty acids in the blood. The aim of this study was to examine the effect of glucose suppression on the uptake of FDG in the infarcted myocardial tissue and also on the determination of ECV in both the infarcted tissue and in the myocardium remote to the zone of infarction during a long constant infusion of FDG and Gd-DTPA.
Extracellular volume was affected neither by suppression nor the length of the constant infusion in remote and infarcted tissue. Metabolic rate of glucose in infarcted tissue decreased during and after suppression of glucose uptake by lipid infusion and heparin injection. An increase in fibrosis and inflammatory cells was found in the center of the infarct as compared to remote tissue.
The decrease in the metabolic rate of glucose in the infarcted tissue suggests that inflammatory cells may be affected by glucose suppression through heparin injection and lipid infusion.
心肌梗死后，纤维化和持续失调的炎症反应已被证明会导致不良的心脏重塑。只要遵守抑制方案，氟代脱氧葡萄糖正电子发射断层扫描（FDG PET）是一种对炎症敏感的成像方式，而钆增强磁共振成像（MRI）可用于测定细胞外容积（ECV），这是一种纤维化的测量指标。在患者中，通过高脂肪饮食、禁食和注射肝素等多种方式实现葡萄糖抑制。为了在犬类中模拟这一过程，使用肝素注射和脂质输注，使血液中的脂肪酸相似。本研究的目的是在长时间持续输注FDG和钆喷酸葡胺（Gd-DTPA）期间，研究葡萄糖抑制对梗死心肌组织中FDG摄取的影响，以及对梗死组织和梗死区域远端心肌中ECV测定的影响。
在远端和梗死组织中，细胞外容积既不受抑制的影响，也不受持续输注时间的影响。在通过脂质输注和肝素注射抑制葡萄糖摄取期间及之后，梗死组织中的葡萄糖代谢率降低。与远端组织相比，在梗死中心发现纤维化和炎症细胞增加。
梗死组织中葡萄糖代谢率的降低表明，炎症细胞可能会受到通过肝素注射和脂质输注进行的葡萄糖抑制的影响。
