20-Hydroxyeicosatetraenoic acid (20-HETE) production is increased in ischemic kidney tissue and may contribute to ischemia/reperfusion (I/R) injury by mediating vasoconstriction and inflammation. To test this hypothesis, uninephrectomized male Lewis rats were exposed to warm ischemia following pretreatment with either an inhibitor of 20-HETE synthesis (HET0016), an antagonist (20-hydroxyeicosa-6(Z),15(Z)-dienoic acid), an agonist (20-hydroxyeicosa-5(Z),14(Z)-dienoic acid), or vehicle via the renal artery and the kidneys were examined 2 days after reperfusion. Pretreatment with either the inhibitor or the antagonist attenuated I/R-induced renal dysfunction as shown by improved creatinine clearance and decreased plasma urea levels, compared to controls. The inhibitor and antagonist also markedly reduced tubular lesion scores, inflammatory cell infiltration, and tubular epithelial cell apoptosis. Administering the antagonist accelerated the recovery of medullary perfusion, as well as renal medullary and cortical re-oxygenation, during the early reperfusion phase. In contrast, the agonist did not improve renal injury and reversed the beneficial effect of the inhibitor. Thus, 20-HETE generation and its action mediated kidney injury due to I/R. Whether or not these effects are clinically important will need to be tested in appropriate human studies.

BackgroundUremic 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 FindingsIn 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-∞) in 5/6N rats, but sitagliptin and alogliptin had significantly higher AUC(0-∞) 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 µmol/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/SignificanceDPP-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.

Dipeptidyl peptidase (DPP)-4 inhibitors delay chronic kidney disease (CKD) progression in experimental diabetic nephropathy in a glucose-independent manner. Here we compared the effects of the DPP-4 inhibitor linagliptin versus telmisartan in preventing CKD progression in non-diabetic rats with 5/6 nephrectomy. Animals were allocated to 1 of 4 groups: sham operated plus placebo; 5/6 nephrectomy plus placebo; 5/6 nephrectomy plus linagliptin; and 5/6 nephrectomy plus telmisartan. Interstitial fibrosis was significantly decreased by 48% with linagliptin but a non-significant 24% with telmisartan versus placebo. The urine albumin-to-creatinine ratio was significantly decreased by 66% with linagliptin and 92% with telmisartan versus placebo. Blood pressure was significantly lowered by telmisartan, but it was not affected by linagliptin. As shown by mass spectrometry, the number of altered peptide signals for linagliptin in plasma was 552 and 320 in the kidney. For telmisartan, there were 108 peptide changes in plasma and 363 in the kidney versus placebo. Linagliptin up-regulated peptides derived from collagen type I, apolipoprotein C1, and heterogeneous nuclear ribonucleoproteins A2/B1, a potential downstream target of atrial natriuretic peptide, whereas telmisartan up-regulated angiotensin II. A second study was conducted to confirm these findings in 5/6 nephrectomy wild-type and genetically deficient DPP-4 rats treated with linagliptin or placebo. Linagliptin therapy in wild-type rats was as effective as DPP-4 genetic deficiency in terms of albuminuria reduction. Thus, linagliptin showed comparable efficacy to telmisartan in preventing CKD progression in non-diabetic rats with 5/6 nephrectomy. However, the underlying pathways seem to be different.

These data demonstrate that AT1R-Abs can induce renal vascular contraction under predisposing conditions such as in ischemic or transplanted kidneys. Neutralizing antibodies against specific epitopes in the AT1R can ameliorate this contraction.

Abstract-We found earlier that deoxycorticosterone acetate-salt treatment causes blood pressure-independent left ventricular hypertrophy, but only in male mice. To test the hypothesis that the estrogen receptor-␤ (ER␤) protects the females from left ventricular hypertrophy, we treated male and female ER␤-deficient (ER␤ Ϫ/Ϫ ) mice and their male and female littermates (wild-type [WT]) with deoxycorticosterone acetate-salt and made them telemetrically normotensive with hydralazine. WT males had increased (ϩ16%) heart weight/tibia length ratios compared with WT females (ϩ7%) at 6 weeks. In ER␤ Ϫ/Ϫ mice, this situation was reversed. Female WT mice had the greatest heart weight/tibia length ratio increases of all of the groups (ϩ23%), even greater than ER␤ Ϫ/Ϫ males (ϩ10%). Echocardiography revealed concentric left ventricular hypertrophy in male WT mice, whereas ER␤ Ϫ/Ϫ females developed dilative left ventricular hypertrophy. The hypertrophic response in female ER␤ Ϫ/Ϫ mice was accompanied by the highest degree of collagen deposition, indicating maladaptive remodeling. ER␤ ϩ/ϩ females showed robust protective p38 and extracellular signal-regulated kinase 1/2 signaling relationships compared with other groups. Calcineurin A␤ expression and its positive regulator myocyte-enriched calcineurin-interacting protein 1 were increased in deoxycorticosterone acetate-salt female ER␤ Ϫ/Ϫ mice, yet lower than in WT males. Endothelin increased murine cardiomyocyte hypertrophy in vitro, which could be blocked by estradiol and an ER␤ agonist. We conclude that a functional ER␤ is essential for inducing adaptive p38 and extracellular signal-regulated kinase signaling, while reducing maladaptive calcineurin signaling in normotensive deoxycorticosterone acetate female mice. Our findings address the possibility of sex-specific cardiovascular therapies. Key Words: estrogen receptor-␤, heart Ⅲ hypertrophy Ⅲ fibrosis Ⅲ calcineurin Ⅲ p38 MAPK Ⅲ ERK1/2 F emales seem to be relatively protected from cardiovascular disease on the basis of animal and human studies; estrogens could play a role. 1-3 Clinical trials using estrogens for improving cardiovascular health were disappointing, perhaps because of poor estrogen receptor (ER) isoform selectivity and specificity. 4 The 2 functional isoforms, ER␣ and ER␤, are expressed in the myocardium. 5 Receptor-mediated effects of estrogens on cardiomyocyte biology are injury or stimulus dependent, 4,6 which, in turn, implicates activation of distinct, sex-dependent, signaling pathways and gene expression programs. 7 We described recently a sex-specific dimorphism in cardiac adaptation in response to deoxycorticosterone acetate (DOCA)-salt and showed that this response was independent of blood pressure. 8 Male mice developed left ventricular hypertrophy (LVH) that was linked to activation of a calcineurin-dependent pathway, which increased proinflammatory and profibrotic responses. In contrast, female DOCA mice maintained their initial physiological adaptive cardiac phenotype despite mineralocorticoid and...

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.

PURPOSE: To evaluate the midterm outcomes of chimney and/or periscope grafts (CPGs) in patients presenting type I endoleak after a previous endovascular aneurysm repair (EVAR). METHODS: Between June 2002 and April 2014, 24 consecutive patients (mean age 73.9±9.2 years; 23 men) presenting a type I endoleak were addressed with CPGs to extend the proximal and/or distal landing zone and to maintain side branch perfusion. Indication for treatment was a type Ia endoleak in 23 (96%) patients and a type Ib endoleak in one. Median interval from the previous EVAR to endoleak treatment with CPGs was 52.2±48.9 months (range 0.2-179). All patients had proximal/distal landing zones precluding any standard endovascular reintervention. Measured outcomes included technical success and perioperative mortality and morbidity. Technical success was defined as a procedure completed as intended, with no secondary procedures within 30 days. Midterm outcomes included survival, CPG patency, endoleaks, and freedom from reintervention. RESULTS: Technical success was 96%; a single patient required an additional procedure to seal a recurrent type Ia endoleak. Intraoperative revascularization of all 55 target vessels (2.3/patient) with CPGs was successful. One (4%) patient died within 30 days. Estimated survival at 12, 24, and 36 months was 83%; estimated CPG patency at the same intervals was 94%. Over a mean follow-up of 23.4±29 months, 6 (25%) reinterventions were performed; of these, 4 were secondary to type I endoleak. Aneurysm diameters reduced from 88.3±26 to 85.5±33 mm (p=0.49) over the mean follow-up. CONCLUSION: The CPG technique is a safe and effective tool for treatment of type I endoleak after previous EVAR. The CPG technique is feasible even in nonelective patients, with excellent outcomes in terms of patency. Close imaging follow-up is warranted to rule out recurrent or de novo endoleaks.

URL://www.clinicaltrials.gov. Unique identifier: NCT01632631.