Turku PET Centre, University of Turku, Turku, Finland.
Turku PET Centre, Turku University Hospital, Turku, Finland.
Am J Physiol Endocrinol Metab. 2019 Nov 1;317(5):E871-E878. doi: 10.1152/ajpendo.00135.2019. Epub 2019 Sep 24.
Human studies of renal hemodynamics and metabolism in obesity are insufficient. We hypothesized that renal perfusion and renal free fatty acid (FFA) uptake are higher in subjects with morbid obesity compared with lean subjects and that they both decrease after bariatric surgery. Cortical and medullary hemodynamics and metabolism were measured in 23 morbidly obese women and 15 age- and sex-matched nonobese controls by PET scanning of [O]-HO (perfusion) and 14()-[F]fluoro-6-thia-heptadecanoate (FFA uptake). Kidney volume and radiodensity were measured by computed tomography, cardiac output by MRI. Obese subjects were re-studied 6 mo after bariatric surgery. Obese subjects had higher renal volume but lower radiodensity, suggesting accumulation of water and/or lipid. Both cardiac output and estimated glomerular filtration rate (eGFR) were increased by ~25% in the obese. Total renal blood flow was higher in the obese [885 (317) (expressed as median and interquartile range) vs. 749 (300) (expressed as means and SD) ml/min of controls, = 0.049]. In both groups, regional blood perfusion was higher in the cortex than medulla; in either region, FFA uptake was ~50% higher in the obese as a consequence of higher circulating FFA levels. Following weight loss (26 ± 8 kg), total renal blood flow was reduced ( = 0.006). Renal volume, eGFR, cortical and medullary FFA uptake were decreased but not fully normalized. Obesity is associated with renal structural, hemodynamic, and metabolic changes. Six months after bariatric surgery, the hemodynamic changes are reversed and the structural changes are improved. On the contrary, renal FFA uptake remains increased, driven by high substrate availability.
肥胖人群的肾脏血液动力学和代谢的人体研究还不够充分。我们假设与正常体重人群相比，病态肥胖人群的肾脏灌注和肾脏游离脂肪酸（FFA）摄取更高，并且在减肥手术后这两者都会下降。通过对[O]-HO（灌注）和 14()-[F]氟-6-硫代十七烷酸（FFA 摄取）的 PET 扫描，对 23 名病态肥胖女性和 15 名年龄和性别匹配的非肥胖对照组进行了皮质和髓质血液动力学和代谢的测量。通过 MRI 测量肾体积和放射密度，通过 MRI 测量心输出量。在减肥手术后 6 个月对肥胖者进行了重新研究。肥胖者的肾体积较大，但放射密度较低，提示水和/或脂质的积累。肥胖者的心脏输出量和估计肾小球滤过率（eGFR）均增加了约 25%。总的肾血流量在肥胖者中更高[885（317）（中位数和四分位距表示）与 749（300）（平均值和 SD 表示）ml/min 相比， = 0.049]。在两组中，皮质的局部血流灌注均高于髓质；在任一区域，肥胖者的 FFA 摄取率都高出约 50%，这是由于循环 FFA 水平较高所致。减肥后（26±8 kg），总肾血流量减少（ = 0.006）。肾体积、eGFR、皮质和髓质 FFA 摄取减少，但未完全恢复正常。肥胖与肾脏结构、血液动力学和代谢变化有关。减肥手术后 6 个月，血液动力学变化得到逆转，结构变化得到改善。相反，由于底物供应充足，肾脏 FFA 摄取仍然增加。
