Refine
Has Fulltext
- no (15)
Document Type
- Article (11)
- Conference Proceeding (3)
- Review (1)
Language
- English (15)
Is part of the Bibliography
- yes (15)
Keywords
- Diabetic nephropathy (2)
- Kidney (2)
- diabetic nephropathy (2)
- linagliptin (2)
- 2k1c renovascular hypertension (1)
- Acute renal failure (1)
- Cardiovascular effects (1)
- Clinical study (1)
- DDP-4 inhibition (1)
- DPP-4 inhibition (1)
Institute
- Institut für Ernährungswissenschaft (15) (remove)
Background: Despite the beneficial effects of type 4 dipeptidyl peptidase (DPP-4) inhibitors on glucose levels, its effects on diabetic nephropathy remain unclear.
Method: This study examined the long-term renoprotective effects of DPP-4 inhibitor linagliptin in db/db mice, a model of type 2 diabetes.
Results were compared with the known beneficial effects of renin-angiotensin system blockade by enalapril. Ten-week-old male diabetic db/db mice were treated for 3 months with either vehicle (n = 10), 3 mg linagliptin/kg per day (n = 8), or 20 mg enalapril/kg per day (n = 10). Heterozygous db/m mice treated with vehicle served as healthy controls (n = 8). Results: Neither linagliptin nor enalapril had significant effects on the parameters of glucose metabolism or blood pressure in diabetic db/db mice. However, linagliptin treatment reduced albuminuria and attenuated kidney injury. In addition, expression of podocyte marker podocalyxin was normalized. We also analysed DPP-4 expression by immunofluorescence in human kidney biopsies and detected upregulation of DPP-4 in the glomeruli of patients with diabetic nephropathy, suggesting that our findings might be of relevance for human kidney disease as well.
Conclusion: Treatment with DPP-4 inhibitor linagliptin delays the progression of diabetic nephropathy damage in a glucose-independent and blood-pressure-independent manner. The observed effects may be because of the attenuation of podocyte injury and inhibition of myofibroblast transformation.
Background: The need for an improved treatment for diabetic nephropathy is greatest in patients who do not adequately respond to angiotensin II receptor blockers (ARBs). This study investigated the effect of the novel dipeptidyl peptidase-4 inhibitor linagliptin alone and in combination with the ARB telmisartan on the progression of diabetic nephropathy in diabetic endothelial nitric oxide synthase (eNOS) knockout mice. Methods: Sixty male eNOS knockout C57BL/6J mice were divided into four groups after receiving intraperitoneal high-dose streptozotocin: telmisartan (1 mg/kg), linagliptin (3 mg/kg), linagliptin + telmisartan (3 mg/kg + 1 mg/kg) and vehicle. Fourteen mice were used as non-diabetic controls. Results: After 12 weeks, urine and blood were obtained and blood pressure measured. Glucose concentrations were increased and similar in all diabetic groups. Telmisartan alone reduced systolic blood pressure by 5.9 mmHg versus diabetic controls (111.2 +/- 2.3 mmHg vs 117.1 +/- 2.2 mmHg; mean +/- SEM; P = 0.071). Combined treatment significantly reduced albuminuria compared with diabetic controls (71.7 +/- 15.3 mu g/24 h vs 170.8 +/- 34.2 mu g/24 h; P = 0.017), whereas the effects of single treatment with either telmisartan (97.8 +/- 26.4 mu g/24 h) or linagliptin (120.8 +/- 37.7 mu g/24 h) were not statistically significant. DPP-4 inhibition, alone and in combination, led to significantly lower plasma osteopontin levels compared with telmisartan alone. Histological analysis revealed reduced glomerulosclerosis after Linagliptin alone and in combination with telmisartan in comparison to non treated diabetic animals (p < 0.01 and p < 0.05). Kidney malonaldehyde immune-reactivity, a marker of oxidative stress, was significantly lower in animals treated with linagliptin. Conclusions: DPP-4 inhibition on top of ARB treatment significantly reduced urinary albumin excretion and oxidative stress in diabetic eNOS knockout mice. Linagliptin on top of an angiotensin II receptor blocker may offer a new therapeutic approach for patients with diabetic nephropathy.
DPP-4 inhibition with linagliptin delays the progression of diabetic nephropathy in db/db mice
(2012)
Background: As the prevalence of diabetes rises, its complications such as diabetic nephropathy affect an increaseing number of patients. Consequently, the need for biomarkers in rodent models which reflect the stage and course of diabetic nephropathy is high. This article focuses on Heart-type fatty acid binding protein (H-FABP), osteopontin (OPN), nephrin, and Neutrophil gelatinase-associated lipocalin (NGAL) in urine, and kidney injury molecule (KIM)-1, clusterin, and tissue inhibitior of metalloproteinases (TIMP) 1 in plasma in uni-nephrectomized rats with streptocotozin-induced type 1 diabetes mellitus, a common animal model to explore renal impairment in the setting of diabetes mellitus.
Methods: 23 male Wistar rats were uni-nephrectomized and subsequently divided into two study groups. The diabetic group received streptozotocin (STZ) via tail-vein injection, the non-diabetic group received citrate buffer without STZ. Subsequently, blood glucose, body weight, and blood pressure were checked regularly. After 18 weeks, animals were placed in metabolic cages, blood and urine obtained and subsequently organs were harvested after sacrifice.
Results: Blood glucose levels were highly increased in diabetic animals throughout the experiment, whereas systolic blood pressure did not differ between the study groups. At study end, classical biomarkers such as urinary albumin and protein and plasma cystatin c were only slightly but not significantly different between groups indicating a very early disease state. In contrast, urinary excretion of H-FABP, OPN, nephrin, and NGAL were highly increased in diabetic animals with a highly significant p-value (p<0.01 each) compared to non-diabetic animals. In plasma, differences were found for calbindin, KIM-1, clusterin, TIMP-1, and OPN. These findings were confirmed by means of the area under the receiver operating characteristic curve (ROC-AUC) analysis.
Conclusions: In summary, our study revealed elevated levels of new plasma and urinary biomarkers (urinary osteopontin, urinary nephrin, urinary NGAL, urinary H-FABP, plasma KIM-1, plasma TIMP-1) in uni-nephrectomized diabetic rats, an established rat model of diabetic nephropathy. These biomarkers appeared even before the classical biomarkers of diabetic nephropathy such as albuminuria and urinary protein excretion. The new biomarkers might offer advantage to urinary albumin and plasma cystatin c with respect to early detection.
Background: Uremic cardiomyopathy contributes substantially to mortality in chronic kidney disease (CKD) patients. Glucagon-like peptide-1 (GLP-1) may improve cardiac function, but is mainly degraded by dipeptidyl peptidase-4 (DPP-4).
Methodology/Principal Findings: In a rat model of chronic renal failure, 5/6-nephrectomized [5/6N] rats were treated orally with DPP-4 inhibitors (linagliptin, sitagliptin, alogliptin) or placebo once daily for 4 days from 8 weeks after surgery, to identify the most appropriate treatment for cardiac dysfunction associated with CKD. Linagliptin showed no significant change in blood level AUC(0-infinity) in 5/6N rats, but sitagliptin and alogliptin had significantly higher AUC(0-infinity) values; 41% and 28% (p=0.0001 and p=0.0324), respectively. No correlation of markers of renal tubular and glomerular function with AUC was observed for linagliptin, which required no dose adjustment in uremic rats. Linagliptin 7 mu mol/kg caused a 2-fold increase in GLP-1 (AUC 201.0 ng/l*h) in 5/6N rats compared with sham-treated rats (AUC 108.6 ng/l*h) (p=0.01). The mRNA levels of heart tissue fibrosis markers were all significantly increased in 5/6N vs control rats and reduced/normalized by linagliptin.
Conclusions/Significance: DPP-4 inhibition increases plasma GLP-1 levels, particularly in uremia, and reduces expression of cardiac mRNA levels of matrix proteins and B-type natriuretic peptides (BNP). Linagliptin may offer a unique approach for treating uremic cardiomyopathy in CKD patients, with no need for dose-adjustment.
Objective:To investigate the effects of linagliptin alone and in combination with the angiotensin II receptor blocker (ARB), telmisartan on blood pressure (BP), kidney function, heart morphology and oxidative stress in rats with renovascular hypertension.Methods:Fifty-seven male Wistar rats underwent unilateral surgical stenosis of the renal artery [2-kidney-1-clip (2k1c) method]. Animals were randomly divided into four treatment groups (n=14-18 per group) receiving: telmisartan (10mg/kg per day in drinking water), linagliptin (89ppm in chow), combination (linagliptin 89ppm+telmisartan 10mg/kg per day) or placebo. An additional group of 12 rats underwent sham surgery. BP was measured one week after surgery. Hypertensive animals entered a 16-week dosing period. BP was measured 2, 4, 8, 12 and 16 weeks after the initiation of treatment. Blood and urine were tested for assessment of kidney function and oxidative stress 6, 10, 14 and 18 weeks after surgery. Blood and urine sampling and organ harvesting were finally performed.Results:Renal stenosis caused an increase in meanSD systolic BP as compared with the sham group (157.7 +/- 29.3 vs. 106.2 +/- 20.5mmHg, respectively; P<0.001). Telmisartan alone and in combination with linagliptin, normalized SBP (111.1 +/- 24.3mmHg and 100.4 +/- 13.9mmHg, respectively; P<0.001 vs. placebo). Telmisartan alone and in combination with linagliptin significantly prevented cardiac hypertrophy, measured by heart weight and myocyte diameter. Renal function measured by cystatin C was not affected by 2k1c surgery. Telmisartan significantly increased plasma concentration of cystatin C. 2k1c surgery initiated fibrosis in both kidneys. Telmisartan promoted further fibrotic changes in the clipped kidney, as measured by protein expression of Col1a1 and histology for interstitial fibrosis and glomerulosclerosis. In non-clipped kidneys, telmisartan demonstrated antifibrotic properties, reducing Col1a1 protein expression. Plasma levels of oxidized low-density lipoprotein were higher in the placebo-treated 2k1c rats as compared to sham-operated animals. The increase was abolished by linagliptin alone (P=0.03 vs. placebo) and in combination with telmisartan (P=0.02 vs. placebo). Combination therapy also significantly reduced plasma concentration of carbonyl proteins (P=0.04 vs. placebo).Conclusion:Inhibition of type 4 dipeptidyl peptidase with linagliptin did not counter BP-lowering effects of ARB in 2k1c rats. Linagliptin reduced lipid and protein oxidation in 2k1c rats, and this effect was BP-independent.
Background The cardiac nitric oxide and endothelin-1 (ET-1) systems are closely linked and play a critical role in cardiac physiology. The balance between both systems is often disturbed in cardiovascular diseases. To define the cardiac effect of excessive ET-1 in a status of nitric oxide deficiency, we compared left ventricular function and morphology in wild-type mice, ET-1 transgenic (ET+/+) mice, endothelial nitric oxide synthase knockout (eNOS(-/-)) mice, and ET(+/+)eNOS(-/-) mice.
Methods and results eNOS(-/-) and ET(+/+)eNOS(-/-) mice developed high blood pressure compared with wild-type and ET+/+ mice. Left ventricular catheterization showed that eNOS(-/-) mice, but not ET(+/+)eNOS(-/-), developed diastolic dysfunction characterized by increased end-diastolic pressure and relaxation constant tau. To elucidate the causal molecular mechanisms driving the rescue of diastolic function in ET(+/+)eNOS(-/-) mice, the cardiac proteome was analyzed. Two-dimensional gel electrophoresis coupled to mass spectrometry offers an appropriate hypothesis-free approach. ET-1 overexpression on an eNOS(-/-) background led to an elevated abundance and change in posttranslational state of antioxidant enzymes (e. g., peroxiredoxin-6, glutathione S-transferase mu 2, and heat shock protein beta 7). In contrast to ET(+/+)eNOS(-/-) mice, eNOS(-/-) mice showed an elevated abundance of proteins responsible for sarcomere disassembly (e. g., cofilin-1 and cofilin-2). In ET(+/+)eNOS(-/-) mice, glycolysis was favored at the expense of fatty acid oxidation.
Conclusion eNOS(-/-) mice developed diastolic dysfunction; this was rescued by ET-1 transgenic overexpression. This study furthermore suggests that cardiac ET-1 overexpression in case of eNOS deficiency causes specifically the regulation of proteins playing a role in oxidative stress, myocytes contractility, and energy metabolism.
Renal and cardiac effects of DPP-4 inhibitors - from preclinical development to clinical research
(2012)
Inhibitors of type 4 dipeptidyl peptidase (DDP-4) were developed and approved for the oral treatment of type 2 diabetes. Its mode of action is to inhibit the degradation of incretins, such as type 1 glucagon like peptide (GLP-1), and GIP. GLP-1 stimulates glucose-dependent insulin secretion from pancreatic beta-cells and suppresses glucagon release from alpha-cells, thereby improving glucose control. Besides its action on the pancreas type 1 glucagon like peptide has direct effects on the heart, vessels and kidney mainly via the type 1 glucagon like peptide receptor (GLP-1R). Moreover, there are substrates of DPP-4 beyond incretins that have proven renal and cardiovascular effects such as BNP/ANP, NPY, PYY or SDF-1 alpha. Preclinical evidence suggests that DPP-4 inhibitors may be effective in acute and chronic renal failure as well as in cardiac diseases like myocardial infarction and heart failure. Interestingly, large cardiovascular meta-analyses of combined Phase II/III clinical trials with DPP-4 inhibitors point all in the same direction: a potential reduction of cardiovascular events in patients treated with these agents. A pooled analysis of pivotal Phase III, placebo-controlled, registration studies of linagliptin further showed a significant reduction of urinary albumin excretion after 24 weeks of treatment. The observation suggests direct renoprotective effects of DPP-4 inhibition that may go beyond its glucose-lowering potential. Type 4 dipeptidyl peptidase inhibitors have been shown to be very well tolerated in general, but for those excreted via the kidney dose adjustments according to renal function are needed to avoid side effects. In conclusion, the direct cardiac and renal effects seen in preclinical studies as well as meta-analysis of clinical trials may offer additional potentials - beyond improvement of glycemic control - for this newer class of drugs, such as acute kidney failure, chronic kidney failure as well as acute myocardial infarction and heart failure.