The protective effect of exercise on diabetic nephropathy : the role of histidine-containing dipeptides

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Safety of Empagliflozin in Patients With Type 2 Diabetes and Chronic Kidney Disease: Pooled Analysis of Placebo-Controlled Clinical Trials

OBJECTIVE: To assess the safety of empagliflozin in patients with type 2 diabetes and moderate to severe chronic kidney disease (CKD) (category G3-4) enrolled in clinical trials. RESEARCH DESIGN AND METHODS: This analysis pooled data from 19 randomized, placebo-controlled, phase 1-4 clinical trials and 1 randomized, placebo-controlled extension study in which patients received empagliflozin 10 mg or 25 mg daily. Time to first occurrence of adverse events (AEs) was evaluated using Kaplan-Meier analysis and multivariable Cox regression models. RESULTS: Among a total of 15,081 patients who received at least one study drug dose, 1,522, 722, and 123 were classified as having G3A, G3B, and G4 CKD, respectively, at baseline. Demographic and clinical characteristics were similar between treatment groups across CKD categories. Rates of serious AEs, AEs leading to discontinuation, and events of special interest (including lower limb amputations and acute renal failure [ARF]) were also similar between empagliflozin and placebo across CKD subgroups. In adjusted Cox regression analyses, risks for volume depletion and ARF were similar for empagliflozin and placebo in the combined group with CKD categories G3B and G4 and the G3A group. Notably lower risks were observed in both groups for hyperkalemia (hazard ratio 0.59 [95% CI 0.37-0.96, P = 0.0323] and 0.48 [0.26-0.91, P = 0.0243], respectively) and edema (0.47 [0.33-0.68, P < 0.0001] and 0.44 [0.28-0.68, P = 0.0002], respectively). CONCLUSIONS: Use of empagliflozin in patients with type 2 diabetes and advanced CKD raised no new safety concerns and may have beneficial effects on the development of hyperkalemia and edema

Human carnosinase 1 overexpression aggravates diabetes and renal impairment in BTBR(Ob/Ob)mice

Objective: To assess the influence of serum carnosinase (CN1) on the course of diabetic kidney disease (DKD). Methods: hCN1 transgenic (TG) mice were generated in a BTBROb/Ob genetic background to allow the spontaneous development of DKD in the presence of serum carnosinase. The influence of serum CN1 expression on obesity, hyperglycemia, and renal impairment was assessed. We also studied if aggravation of renal impairment in hCN1 TG BTBROb/Ob mice leads to changes in the renal transcriptome as compared with wild-type BTBROb/Ob mice. Results: hCN1 was detected in the serum and urine of mice from two different hCN1 TG lines. The transgene was expressed in the liver but not in the kidney. High CN1 expression was associated with low plasma and renal carnosine concentrations, even after oral carnosine supplementation. Obese hCN1 transgenic BTBROb/Ob mice displayed significantly higher levels of glycated hemoglobin, glycosuria, proteinuria, and increased albumin-creatinine ratios (1104 ± 696 vs 492.1 ± 282.2 μg/mg) accompanied by an increased glomerular tuft area and renal corpuscle size. Gene-expression profiling of renal tissue disclosed hierarchical clustering between BTBROb/Wt, BTBROb/Ob, and hCN1 BTBROb/Ob mice. Along with aggravation of the DKD phenotype, 26 altered genes have been found in obese hCN1 transgenic mice; among them claudin-1, thrombospondin-1, nephronectin, and peroxisome proliferator–activated receptor-alpha have been reported to play essential roles in DKD. Conclusions: Our data support a role for serum carnosinase 1 in the progression of DKD. Whether this is mainly attributed to the changes in renal carnosine concentrations warrants further studies. Key messages: Increased carnosinase 1 (CN1) is associated with diabetic kidney disease (DKD).BTBROb/Ob mice with human CN1 develop a more aggravated DKD phenotype.Microarray revealed alterations by CN1 which are not altered by hyperglycemia.These genes have been described to play essential roles in DKD.Inhibiting CN1 could be beneficial in DKD

Hyperglycemia Does Not Affect Iron Mediated Toxicity of Cultured Endothelial and Renal Tubular Epithelial Cells:Influence of L-Carnosine

Iron has been suggested to affect the clinical course of type 2 diabetes (T2DM) as accompanying increased intracellular iron accumulation may provide an alternative source for reactive oxygen species (ROS). Although carnosine has proven its therapeutic efficacy in rodent models of T2DM, little is known about its efficacy to protect cells from iron toxicity. We sought to assess if high glucose (HG) exposure makes cultured human umbilical vein endothelial cells (HUVECs) and renal proximal tubular epithelial cells (PTECs) more susceptible to metal induced toxicity and if this is ameliorated by L-carnosine. HUVECs and PTECs, cultured under normal glucose (5 mM, NG) or HG (30 mM), were challenged for 24 h with FeCl3. Cell viability was not impaired under HG conditions nor did HG increase susceptibility to FeCl3. HG did not change the expression of divalent metal transporter 1 (DMT1), ferroportin (IREG), and transferrin receptor protein 1 (TFRC). Irrespective of glucose concentrations L-carnosine prevented toxicity in a dose-dependent manner, only if it was present during the FeCl3 challenge. Hence our study indicates that iron induced cytotoxicity is not enhanced under HG conditions. L-Carnosine displayed a strong protective effect, most likely by chelation of ironmediated toxicity

Cardiac and Kidney Benefits of Empagliflozin in Heart Failure Across the Spectrum of Kidney Function: Insights From EMPEROR-Reduced.

BACKGROUND: In EMPEROR-Reduced (Empagliflozin Outcome Trial in Patients With Chronic Heart Failure With Reduced Ejection Fraction), empagliflozin reduced cardiovascular death or heart failure (HF) hospitalization and total HF hospitalizations, and slowed the progressive decline in kidney function in patients with HF and a reduced ejection fraction, with and without diabetes. We aim to study the effect of empagliflozin on cardiovascular and kidney outcomes across the spectrum of kidney function. METHODS: In this prespecified analysis, patients were categorized by the presence or absence of chronic kidney disease (CKD) at baseline (estimated glomerular filtration rate [eGFR] 300 mg/g). The primary and key secondary outcomes were: (1) a composite of cardiovascular death or HF hospitalization (primary outcome); (2) total HF hospitalizations; and (3) eGFR slope. The direct impact on kidney events was investigated by a prespecified composite kidney outcome (defined as a sustained profound decline in eGFR, chronic dialysis, or transplant). The median follow-up was 16 months. RESULTS: Of 3730 patients who were randomized to empagliflozin or placebo, 1978 (53%) had CKD. Empagliflozin reduced the primary outcome and total HF hospitalizations in patients with and without CKD: hazard ratio (HR)=0.78 (95% CI, 0.65-0.93) and HR=0.72 (95% CI, 0.58-0.90), respectively (interaction P=0.63). Empagliflozin slowed the slope of eGFR decline by 1.11 (0.23-1.98) ml/min/1.73 m2/yr in patients with CKD and by 2.41 (1.49-3.32) ml/min/1.73 m2/yr in patients without CKD. The risk of the composite kidney outcome was reduced similarly in patients with and without CKD: HR=0.53 (95% CI, 0.31-0.91) and HR=0.46 (95% CI, 0.22-0.99), respectively. The effect of empagliflozin on the primary composite outcome and key secondary outcomes was consistent across a broad range of baseline kidney function, measured by clinically relevant eGFR subgroups or by albuminuria, including patients with eGFR as low as 20 ml/min/1.73 m2. Empagliflozin was well tolerated in CKD patients. CONCLUSIONS: In EMPEROR-Reduced, empagliflozin had a beneficial effect on the key efficacy outcomes and slowed the rate of kidney function decline in patients with and without CKD, and regardless of the severity of kidney impairment at baseline. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03057977

Influence of endpoint definitions on the effect of empagliflozin on major renal outcomes in the EMPEROR-Preserved trial.

RESEARCH LETTER - No abstract available

Methylglyoxal down-regulates the expression of cell cycle associated genes and activates the p53 pathway in human umbilical vein endothelial cells

Abstract Although methylglyoxal (MGO) has emerged as key mediator of diabetic microvascular complications, the influence of MGO on the vascular transcriptome has not thoroughly been assessed. Since diabetes is associated with low grade inflammation causing sustained nuclear factor-kappa B (NF-κB) activation, the current study addressed 1) to what extent MGO changes the transcriptome of human umbilical vein endothelial cells (HUVECs) exposed to an inflammatory milieu, 2) what are the dominant pathways by which these changes occur and 3) to what extent is this affected by carnosine, a putative scavenger of MGO. Microarray analysis revealed that exposure of HUVECs to high MGO concentrations significantly changes gene expression, characterized by prominent down-regulation of cell cycle associated genes and up-regulation of heme oxygenase-1 (HO-1). KEGG-based pathway analysis identified six significantly enriched pathways of which the p53 pathway was the most affected. No significant enrichment of inflammatory pathways was found, yet, MGO did inhibit VCAM-1 expression in Western blot analysis. Carnosine significantly counteracted MGO-mediated changes in a subset of differentially expressed genes. Collectively, our results suggest that MGO initiates distinct transcriptional changes in cell cycle/apoptosis genes, which may explain MGO toxicity at high concentrations. MGO did not augment TNF-α induced inflammation

The CNDP1 (CTG)(5) Polymorphism Is Associated with Biopsy-Proven Diabetic Nephropathy, Time on Hemodialysis, and Diabetes Duration

Considering that the homozygous CNDP1 (CTG)5 genotype affords protection against diabetic nephropathy (DN) in female patients with type 2 diabetes, this study assessed if this association remains gender-specific when applying clinical inclusion criteria (CIC-DN) or biopsy proof (BP-DN). Additionally, it assessed if the prevalence of the protective genotype changes with diabetes duration and time on hemodialysis and if this occurs in association with serum carnosinase (CN-1) activity. Whereas the distribution of the (CTG)5 homozygous genotype in the no-DN and CIC-DN patients was comparable, a lower frequency was found in the BP-DN patients, particularly in females. We observed a significant trend towards high frequencies of the (CTG)5 homozygous genotype with increased time on dialysis. This was also observed for diabetes duration but only reached significance when both (CTG)5 homo- and heterozygous patients were included. CN-1 activity negatively correlated with time on hemodialysis and was lower in (CTG)5 homozygous patients. The latter remained significant in female subjects after gender stratification. We confirm the association between the CNDP1 genotype and DN to be likely gender-specific. Although our data also suggest that (CTG)5 homozygous patients may have a survival advantage on dialysis and in diabetes, this hypothesis needs to be confirmed in a prospective cohort study

Carnosine Attenuates the Development of both Type 2 Diabetes and Diabetic Nephropathy in BTBR ob/ob Mice

We previously demonstrated that polymorphisms in the carnosinase-1 gene (CNDP1) determine the risk of nephropathy in type 2 diabetic patients. Carnosine, the substrate of the enzyme encoded by this gene, is considered renoprotective and could possibly be used to treat diabetic nephropathy (DN). In this study, we examined the effect of carnosine treatment in vivo in BTBR (Black and Tan, BRachyuric) ob/ob mice, a type 2 diabetes model which develops a phenotype that closely resembles advanced human DN. Treatment of BTBR ob/ob mice with 4 mM carnosine for 18 weeks reduced plasma glucose and HbA1c, concomitant with elevated insulin and C-peptide levels. Also, albuminuria and kidney weights were reduced in carnosine-treated mice, which showed less glomerular hypertrophy due to a decrease in the surface area of Bowman's capsule and space. Carnosine treatment restored the glomerular ultrastructure without affecting podocyte number, resulted in a modified molecular composition of the expanded mesangial matrix and led to the formation of carnosine-acrolein adducts. Our results demonstrate that treatment with carnosine improves glucose metabolism, albuminuria and pathology in BTBR ob/ob mice. Hence, carnosine could be a novel therapeutic strategy to treat patients with DN and/or be used to prevent DN in patients with diabetes