Dipeptidyl peptidase-4 inhibitor linagliptin reduces urinary albumin excretion through the protection of glomerular endothelial function

　Background: In most developed countries, diabetic kidney disease is the most common cause of chronic kidney disease, leading to end-stage renal disease, and it is also associated with cardiovascular diseases, including heart failure, and a higher risk of other microvascular complications. A recent clinical trial indicated that the dipeptidyl peptidase-4 inhibitor linagliptin prevents the occurrence and progression of albuminuria in patients with type 2 diabetes. Thus, this study aimed to elucidate the molecular mechanism underlying the inhibitory effect of linagliptin on albuminuria in diabetic kidney disease. Methods: Control C57BL/6 mice and diabetic Ins2+/Akita mice were orally administered linagliptin (5 mg/kg/ day) every day for 8 weeks. Results: Compared to control mice, Ins2+/Akita mice had markedly elevated blood glucose and HbA1c levels, but there were no significant changes after linagliptin treatment. Furthermore, albuminuria and urinary 8-OHdG levels were significantly increased and glomerular mesangial area was significantly expanded in Ins2+/Akita mice compared to those in control mice; these changes were ameliorated by linagliptin treatment, which also improved the degradation of glomerular endothelial glycocalyx and enhancement of glomerular permeability of macromolecules. The activity of AMP-activated protein kinase and the expression of guanosine 5\u27-triphosphate cyclohydrolase I in human glomerular endothelial cells were significantly lower in high glucose conditions and were improved by linagliptin or GLP-1 administration. Discussion: These results together suggest that linagliptin reduced albuminuria in a blood glucose-independent manner via the reduction of oxidative stress and maintenance of the glycocalyx in endothelial cells. Thus, earlier treatment with linagliptin may slow the progression of diabetic kidney disease

Empagliflozin in Patients with Chronic Kidney Disease

Background The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. Methods We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m(2) of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m(2) with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to < 10 ml per minute per 1.73 m(2), a sustained decrease in eGFR of & GE;40% from baseline, or death from renal causes) or death from cardiovascular causes. Results A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P < 0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P=0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. Conclusions Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo