ABSTRACT
Objective:To evaluate the effect of canagliflozin on intrarenal fat content and oxygenation in newly-diagnosed type 2 diabetes patients.Methods:Twenty-three newly-diagnosed type 2 diabetes patients were divided into canagliflozin( n=11) and glimepiride control( n=12) groups .Both groups received MRI scanning with Dixon MRI and BOLD MRI sequence to assess patients′ intrarenal fat content, oxygenation level before treatment and 24 weeks after treatment. Fasting blood glucose, glycosylated hemoglobin, blood uric acid, blood lipids, blood pressure, weight, and other metabolic index were also tested before and after treatment. Furthermore, the relationship between body mass index(BMI) and intrarenal fat content and the correlation between changes in intrarenal fat content and improvement in renal hypoxia were analyzed. Results:No significant differences were found in baseline age, body weight, fasting blood glucose, glycosylated hemoglobin, blood lipid, and serum uric acid between the two groups. There was no significant difference in fasting blood glucose, glycosylated hemoglobin, cholesterol(CHO), low-density lipoprotein-cholesterol(LDL-C), and triglycerides(TG) levels in both groups after 12 and 24 weeks of treatment. The decrease in body weight, blood uric acid level, and diastolic blood pressure from baseline in the canagliflozin group was greater than those in the control group( P<0.05). Two groups of patients with type 2 diabetes at baseline had no obvious difference in intrarenal fat content, and the patients′ BMI showed no obvious correlation with degree of intrarenal fat accumulation. Canagliflozin treatment for 24 weeks could reduce intrarenal fat content, which was higher than that of control group. The R2 * values of renal cortex and medulla in the canagliflozin group decreased from baseline by 19.22% and 22.63% respectively( P<0.05), whereas no significant difference was seen in the glimepiride control group. The decrease of intrarenal fat content in the canagliflozin group was related to the improvement of renal cortex and medulla oxygenation. Conclusion:Canagliflozin can reduce intrarenal fat accumulation and improve renal cortical hypoxia in newly diagnosed type 2 diabetes patients with normal renal function.
ABSTRACT
OBJECTIVE: To assess the feasibility of susceptibility-weighted imaging (SWI) while monitoring changes in renal oxygenation level after water loading. MATERIALS AND METHODS: Thirty-two volunteers (age, 28.0 +/- 2.2 years) were enrolled in this study. SWI and multi-echo gradient echo sequence-based T2* mapping were used to cover the kidney before and after water loading. Cortical and medullary parameters were measured using small regions of interest, and their relative changes due to water loading were calculated based on baseline and post-water loading data. An intraclass correlation coefficient analysis was used to assess inter-observer reliability of each parameter. A receiver operating characteristic curve analysis was conducted to compare the performance of the two methods for detecting renal oxygenation changes due to water loading. RESULTS: Both medullary phase and medullary T2* values increased after water loading (p 0.05). Interobserver reliability was excellent for the T2* values, good for SWI cortical phase values, and moderate for the SWI medullary phase values. The area under receiver operating characteristic curve of the SWI medullary phase values was 0.85 and was not different from the medullary T2* value (0.84). CONCLUSION: Susceptibility-weighted imaging enabled monitoring changes in the oxygenation level in the medulla after water loading, and may allow comparable feasibility to detect renal oxygenation level changes due to water loading compared with that of T2* mapping.
Subject(s)
Adult , Female , Humans , Male , Young Adult , Kidney/metabolism , Magnetic Resonance Imaging/methods , Oxygen/blood , ROC Curve , Reproducibility of Results , Water/administration & dosageABSTRACT
OBJECTIVE: The association between renal hypoxia and the development of renal injury is well established. However, no adequate method currently exists to non-invasively measure functional changes in renal oxygenation in normal and injured patients. METHOD: R2* quantification was performed using renal blood oxygen level-dependent properties. Five healthy normotensive women (50±5.3 years) underwent magnetic resonance imaging in a 1.5T Signa Excite HDx scanner (GE Healthcare, Waukesha, WI). A multiple fast gradient-echo sequence was used to acquire R2*/T2* images (sixteen echoes from 2.1 ms/slice to 49.6 ms/slice in a single breath hold per location). The images were post-processed to generate R2* maps for quantification. Data were recorded before and at 30 minutes after the oral administration of an angiotensin II-converting enzyme inhibitor (captopril, 25 mg). The results were compared using an ANOVA for repeated measurements (mean + standard deviation) followed by the Tukey test. ClinicalTrials.gov: NCT01545479. RESULTS: A significant difference (p<0.001) in renal oxygenation (R2*) was observed in the cortex and medulla before and after captopril administration: right kidney, cortex = 11.08 ± 0.56ms, medulla = 17.21 ± 1.47ms and cortex = 10.30 ± 0.44ms, medulla = 16.06 ± 1.74ms, respectively; and left kidney, cortex= 11.79 ± 1.85ms, medulla = 17.03 ± 0.88ms and cortex = 10.89 ± 0.91ms, medulla = 16.43 ± 1.49ms, respectively. CONCLUSIONS: This result suggests that the technique efficiently measured alterations in renal blood oxygenation after angiotensin II-converting enzyme inhibition and that it may provide a new strategy for identifying the early stages of renal disease and perhaps new therapeutic targets.