FDG uptake and glucose transporter subtype expressions in experimental tumor and inflammation models.

Although FDG uptake is closely related to the expression of the glucose transporter (GLUT) in malignant tumors, such a relationship has not been fully investigated in inflammatory lesions. The aim of our study was to determine the expression of GLUT subtypes in experimental inflammatory lesions and to compare the results with those in malignant tumors in relation to FDG accumulation. METHODS: Rats were inoculated with a suspension of Staphylococcus aureus or allogenic hepatoma cells (KDH-8) into the left calf muscle. Five days after S. aureus inoculation (n = 9) and 14 d after KDH-8 inoculation (n = 11), (14)C]FDG was injected intravenously and its accumulation in the infectious and tumor tissues was determined as the percentage activity of the injected dose per gram of tissue (%ID/g). The expression of glucose transporters (GLUT-1 to GLUT-5) was investigated by immunostaining the infectious tissues (n = 6) and the tumor tissues (n = 6). Immunohistochemical grading was assessed semiquantitatively by 5 observers. RESULTS: The (14)C]FDG uptake was significantly higher in the tumor lesion than in the inflammatory lesion (2.04 +/- 0.38 %ID/g vs. 0.72 +/- 0.15 %ID/g; P < 0.0001). The tumor and inflammatory tissues highly expressed GLUT-1 and GLUT-3. The GLUT-1 expression level was significantly higher in the tumor tissue than in the inflammatory tissue (P < 0.05). CONCLUSION: The results based on our models showed a high FDG uptake and high GLUT-1 expression level not only in the tumor lesion but also in the inflammatory lesion. The higher GLUT-1 expression level in the tumor lesion may partially explain the higher FDG accumulation in the tumor than in the inflammatory lesion.