BDNF and diabetic kidney disease: On the other hand, down-regulation of active p-PI3K, p-Akt, and p-mTOR by ceramide, resveratrol, brain-derived neurotrophic factor (BDNF), or oleanolic acid stimulates protective autophagy in pathological disease models, such as myocardial hypertrophy, ischemic brain injury, or diabetic nephropathy [49,50,51,52].