Chronic Activation of Heme Free Guanylate Cyclase Leads to Renal Protection in Dahl Salt-Sensitive Rats

<div><p>The nitric oxide (NO)/soluble guanylate cyclase (sGC)/cyclic guanosine monophasphate (cGMP)-signalling pathway is impaired under oxidative stress conditions due to oxidation and subsequent loss of the prosthetic sGC heme group as observed in particular in chronic renal failure. Thus, the pool of heme free sGC is increased under pathological conditions. sGC activators such as cinaciguat selectively activate the heme free form of sGC and target the disease associated enzyme. In this study, a therapeutic effect of long-term activation of heme free sGC by the sGC activator cinaciguat was investigated in an experimental model of salt-sensitive hypertension, a condition that is associated with increased oxidative stress, heme loss from sGC and development of chronic renal failure. For that purpose Dahl/ss rats, which develop severe hypertension upon high salt intake, were fed a high salt diet (8% NaCl) containing either placebo or cinaciguat for 21 weeks. Cinaciguat markedly improved survival and ameliorated the salt-induced increase in blood pressure upon treatment with cinaciguat compared to placebo. Renal function was significantly improved in the cinaciguat group compared to the placebo group as indicated by a significantly improved glomerular filtration rate and reduced urinary protein excretion. This was due to anti-fibrotic and anti-inflammatory effects of the cinaciguat treatment. Taken together, this is the first study showing that long-term activation of heme free sGC leads to renal protection in an experimental model of hypertension and chronic kidney disease. These results underline the promising potential of cinaciguat to treat renal diseases by targeting the disease associated heme free form of sGC.</p></div

Histological analysis of tissues from rats on a high salt diet with or without (placebo) cinaciguat.

<p>Respective sections of myocardial (a) and pulmonary (b) artery, kidney (c) and lung (d) are shown. Sections were HE-stained, kidney sections are additionally PAS-stained. Magnitude is given beyond the respective picture.</p

<i>In vivo</i>-parameters.

<p>Relative effects of oral treatment with cinaciguat on systolic blood pressure (a), heart rate (b), survival (c) and body weight (d) of Dahl/ss rats on high salt diet (8% NaCl). Data are shown as means ± SEM. Initial values of systolic blood pressure were 176.7 ± 3.6 mmHg and 182.8 ± 3.5 and heart rate were 409.4 ± 3.6 bpm and 407.2 ± 4.9 bpm in the placebo and the cinaciguat group, respectively. At beginning of the study animals weighed 335.5 ± 5.1 g and 339.9 ± 3.9 g in the placebo and the cinaciguat group, respectively. *<i>p</i> < 0.05; ***<i>p</i> < 0.005: Student’s <i>t</i>-test (cinaciguat vs. placebo).</p

Results of M-Mode echocardiographic analysis performed one week before study end.

<p>Fractional shortening (a), diastolic (b) and systolic (c) diameter of the left ventricle, diametric increase between diastole and systole of the septum (d) and left free wall (e), conditions between septum and left free wall (f) as well as diastolic diameter of left free wall (g) and septum (h) were analysed in 14 (placebo) and 16 (cinaciguat) animals. Data are means ± SEM. ***p < 0.005: Student’s t-test (cinaciguat vs. placebo). 14 animals of the placebo group and 16 animals of the cinaciguat group were analyzed.</p

Effect of salt load and cinaciguat treatment on relative mRNA expression of pro-inflammatory and pro-fibrotic biomarker genes.

<p>Relative expression of the pro-inflammatory markers <i>monocyte chemoattractant protein-1</i> (<i>Mcp1</i>) and of the pro-fibrotic markers <i>collagen1α1</i> (<i>Col1a1</i>), <i>fibronectin-1</i> (<i>Fn1</i>), <i>osteopontin</i> (<i>Spp1</i>), and <i>tenascin-C</i> (<i>Tnc</i>) was assessed in kidney (a) and left ventricle (b) in control animals kept on normal diet and in animals kept on high salt diet (8% NaCl) receiving either placebo or cinaciguat. Data are means ± SEM. *<i>p</i> < 0.05; **<i>p</i> < 0.01; ***<i>p</i> < 0.005: Student’s <i>t</i>-test; ns = not significant. 8 animals in the control group, 10 animals of the placebo group and 15 animals of the cinaciguat group were analyzed.</p

Abdominal diameter of male (A) and female (B) offspring in relationship to paternal BMI.

<p>Ultrasound examination was done in average at gestational day 266.8. Black Bar: Paternal BMI below median; Hatched Bar: Paternal BMI above median. &: p = 0.003 versus male offspring of fathers with a BMI below the median of all paternal BMI data.</p

Image_1_25(OH)D-but not 1,25(OH)2D–Is an independent risk factor predicting graft loss in stable kidney transplant recipients.pdf

BackgroundVitamin D deficiency (VDD) or vitamin D insufficiency is common in kidney transplant recipients (KTRs). The impact of VDD on clinical outcomes in KTRs remain poorly defined and the most suitable marker for assessing vitamin D nutritional status in KTRs is unknown so far.MethodsWe conducted a prospective study including 600 stable KTRs (367 men, 233 women) and a meta-analysis to pool existing evidence to determine whether 25(OH)D or 1,25(OH)2D predicted graft failure and all-cause mortality in stable KTRs.ResultsCompared with a higher 25(OH)D concentration, a low concentration of 25(OH)D was a risk factor for graft failure (HR 0.946, 95% CI 0.912−0.981, p = 0.003), whereas 1,25 (OH)2D was not associated with the study end-point graft loss (HR 0.993, 95% CI 0.977−1.009, p = 0.402). No association was found between either 25(OH)D or 1,25 (OH)2D and all-cause mortality. We furthermore conducted a meta-analysis including 8 studies regarding the association between 25(OH)D or 1,25(OH)2D and graft failure or mortality, including our study. The meta-analysis results were consistent with our study in finding that lower 25(OH)D levels were significantly associated with the risk of graft failure (OR = 1.04, 95% CI: 1.01−1.07), but not associated with mortality (OR = 1.00, 95% CI: 0.98−1.03). Lower 1,25(OH)2D levels were not associated with the risk of graft failure (OR = 1.01, 95% CI: 0.99−1.02) and mortality (OR = 1.01, 95% CI: 0.99−1.02).ConclusionBaseline 25(OH)D concentrations but not 1,25(OH)2D concentrations were independently and inversely associated with graft loss in adult KTRs.</p

Image_2_25(OH)D-but not 1,25(OH)2D–Is an independent risk factor predicting graft loss in stable kidney transplant recipients.pdf

BackgroundVitamin D deficiency (VDD) or vitamin D insufficiency is common in kidney transplant recipients (KTRs). The impact of VDD on clinical outcomes in KTRs remain poorly defined and the most suitable marker for assessing vitamin D nutritional status in KTRs is unknown so far.MethodsWe conducted a prospective study including 600 stable KTRs (367 men, 233 women) and a meta-analysis to pool existing evidence to determine whether 25(OH)D or 1,25(OH)2D predicted graft failure and all-cause mortality in stable KTRs.ResultsCompared with a higher 25(OH)D concentration, a low concentration of 25(OH)D was a risk factor for graft failure (HR 0.946, 95% CI 0.912−0.981, p = 0.003), whereas 1,25 (OH)2D was not associated with the study end-point graft loss (HR 0.993, 95% CI 0.977−1.009, p = 0.402). No association was found between either 25(OH)D or 1,25 (OH)2D and all-cause mortality. We furthermore conducted a meta-analysis including 8 studies regarding the association between 25(OH)D or 1,25(OH)2D and graft failure or mortality, including our study. The meta-analysis results were consistent with our study in finding that lower 25(OH)D levels were significantly associated with the risk of graft failure (OR = 1.04, 95% CI: 1.01−1.07), but not associated with mortality (OR = 1.00, 95% CI: 0.98−1.03). Lower 1,25(OH)2D levels were not associated with the risk of graft failure (OR = 1.01, 95% CI: 0.99−1.02) and mortality (OR = 1.01, 95% CI: 0.99−1.02).ConclusionBaseline 25(OH)D concentrations but not 1,25(OH)2D concentrations were independently and inversely associated with graft loss in adult KTRs.</p

Biparietal diameter of male (A) and female (B) offspring in relationship to paternal BMI.

<p>Ultrasound examination was done in average at gestational day 266.8. Black Bar: Paternal BMI below median; Hatched Bar: Paternal BMI above median. #: p = 0.008 versus male offspring of fathers with a BMI below the median of all paternal BMI data of the cohort; Data are given as mean +/− SEM.</p

Multivariable regression analysis of factors predicting fetal cortisol in male and female new-born.

<p>B: partial regression coefficient; 95% CI: 95% Confidence Interval for B,</p