Iments were not designed 
to distinguish between these possibilities, these warrant further study. However, the lack of a full mechanistic explanation for our findings may not be necessary before clinical application. Interestingly, the FDG retention during the late plateau phase was lower for anti-GBM mice on day 7 compared to day 0. While molecular mechanisms were not the main focus of the current work, we did examine expression of the main transporters for FDG in the kidneys. As it has been reported that the use of an SGLT inhibitor increases 18F-FDG in urine the decreased expression of SGLTs 1 and 2 is consistent with, but may not be the only cause of this deeper drop [17]. The amplitude of the kidney Pentagastrin web uptake declined dramatically on days 10, 14, and 21 in reciprocal relationship to sCr and proteinuria, which remained high compared to day 0 levels. A similar lack of correlation between measures of renal function and FDG uptake has been observed in rat models of allogenic transplantation [19]. This further emphasizes the relationship between markers of inflammation and renal retention of FDG. Many currently available clinical imaging techniques have been applied for the diagnosis and follow-up of lupus nephritis. Ultrasound (US) has been used to evaluate the abnormalities ofImaging Assessment of Lupus NephritisTable 2. PET imaging parameters and renal function/pathological changes in anti-GBM nephritis mice.ParameterDayDayDayDayDayPET imaging analysisUptakemax ( ID/g) tmax (min) AUC ( ID?min?g21) 39.060.5 1.960.5 948614* 40.360.8 8.763.8 1022631 18.561.7* ,1.0 327618* 13.861.3* ,1.0 325612* 11.361.0* ,1.0 270617*Renal function/pathological changessCr (mg/dl) Proteinuria GN score Crescent formation VCAM-1 (serum) VCAM-1/Creatinine (urine) 0.19060.019* 0.22960.171* 0 0 305172646956* 23622* 0.22960.033 0.90960.295 2.760.6 0 ��-Sitosterol ��-D-glucoside chemical information 7366386136727 5136229 0.25160.230 1.37660.190* 3.361.1 2.060.7* 439871664455* 7936164 0.34960.082* 1.88660.389* 4.060* 23612* 321336657250* 8806353 0.24060.029 1.67260.500* 4.060* 9060* 4745696108318*Uptakemax: the maximum kidney uptake; tmax: the corresponding time of Uptakemax; AUC: the area under the time-activity curve during the disease characteristic uptake phase (0?0 min). sCr: serum creatinine; BUN: blood urea nitrogen; GN score: glomerulonephritis score. Data was shown as mean6standard deviation. Note: The symbols indicate significant differences compared to Day 7 data under the same parameter with *p,0.05. doi:10.1371/journal.pone.0057418.trenal morphology and cortical echogenicity [20]. Other studies have reported the use of diffusion-weighted [21] and T2-weighted [22] magnetic resonance imaging (MRI) and duplex doppler sonography [23] for lupus nephritis. Both of these modalities are largely based on morphological changes with some sensitivity in depicting inflammation associated edema directly or indirectly. Aswith inflammation in other diseases, the inflammatory cells of lupus nephritis are expected to be glucose avid [5?]. Thus we predict FDG-PET would be more sensitive to early changes and therapeutic interventions. Moreover, some patients suffer from claustrophobia and will not undergo MR scanning. Conventional nuclear medicine imaging approaches using 67Ga-citrate, 111In orFigure 4. Representative 3D PET-CT images from the dynamic imaging interval of 10?5 min (frame No.3) on days 0 and 7 in antiGBM nephritis group mice. Left: Day 0 (prior to rabbit IgG injection); Right: Day 7. H – heart, L – left k.Iments were not designed to distinguish between these possibilities, these warrant further study. However, the lack of a full mechanistic explanation for our findings may not be necessary before clinical application. Interestingly, the FDG retention during the late plateau phase was lower for anti-GBM mice on day 7 compared to day 0. While molecular mechanisms were not the main focus of the current work, we did examine expression of the main transporters for FDG in the kidneys. As it has been reported that the use of an SGLT inhibitor increases 18F-FDG in urine the decreased expression of SGLTs 1 and 2 is consistent with, but may not be the only cause of this deeper drop [17]. The amplitude of the kidney uptake declined dramatically on days 10, 14, and 21 in reciprocal relationship to sCr and proteinuria, which remained high compared to day 0 levels. A similar lack of correlation between measures of renal function and FDG uptake has been observed in rat models of allogenic transplantation [19]. This further emphasizes the relationship between markers of inflammation and renal retention of FDG. Many currently available clinical imaging techniques have been 
applied for the diagnosis and follow-up of lupus nephritis. Ultrasound (US) has been used to evaluate the abnormalities ofImaging Assessment of Lupus NephritisTable 2. PET imaging parameters and renal function/pathological changes in anti-GBM nephritis mice.ParameterDayDayDayDayDayPET imaging analysisUptakemax ( ID/g) tmax (min) AUC ( ID?min?g21) 39.060.5 1.960.5 948614* 40.360.8 8.763.8 1022631 18.561.7* ,1.0 327618* 13.861.3* ,1.0 325612* 11.361.0* ,1.0 270617*Renal function/pathological changessCr (mg/dl) Proteinuria GN score Crescent formation VCAM-1 (serum) VCAM-1/Creatinine (urine) 0.19060.019* 0.22960.171* 0 0 305172646956* 23622* 0.22960.033 0.90960.295 2.760.6 0 7366386136727 5136229 0.25160.230 1.37660.190* 3.361.1 2.060.7* 439871664455* 7936164 0.34960.082* 1.88660.389* 4.060* 23612* 321336657250* 8806353 0.24060.029 1.67260.500* 4.060* 9060* 4745696108318*Uptakemax: the maximum kidney uptake; tmax: the corresponding time of Uptakemax; AUC: the area under the time-activity curve during the disease characteristic uptake phase (0?0 min). sCr: serum creatinine; BUN: blood urea nitrogen; GN score: glomerulonephritis score. Data was shown as mean6standard deviation. Note: The symbols indicate significant differences compared to Day 7 data under the same parameter with *p,0.05. doi:10.1371/journal.pone.0057418.trenal morphology and cortical echogenicity [20]. Other studies have reported the use of diffusion-weighted [21] and T2-weighted [22] magnetic resonance imaging (MRI) and duplex doppler sonography [23] for lupus nephritis. Both of these modalities are largely based on morphological changes with some sensitivity in depicting inflammation associated edema directly or indirectly. Aswith inflammation in other diseases, the inflammatory cells of lupus nephritis are expected to be glucose avid [5?]. Thus we predict FDG-PET would be more sensitive to early changes and therapeutic interventions. Moreover, some patients suffer from claustrophobia and will not undergo MR scanning. Conventional nuclear medicine imaging approaches using 67Ga-citrate, 111In orFigure 4. Representative 3D PET-CT images from the dynamic imaging interval of 10?5 min (frame No.3) on days 0 and 7 in antiGBM nephritis group mice. Left: Day 0 (prior to rabbit IgG injection); Right: Day 7. H – heart, L – left k.
