Chen Q.,University of California at San Francisco |
Sievers R.E.,University of California at San Francisco |
Varga M.,University of California at San Francisco |
Kharait S.,University of California at San Francisco |
And 8 more authors.
Journal of Applied Physiology | Year: 2013
Nitric oxide (NO) exerts a wide range of cellular effects in the cardiovascular system. NO is short lived, but S-nitrosoglutathione (GSNO) functions as a stable intracellular bioavailable NO pool. Accordingly, increased levels can facilitate NO-mediated processes, and conversely, catabolism of GSNO by the regulatory enzyme GSNO reductase (GSNOR) can impair these processes. Because dysregulated GSNOR can interfere with processes relevant to cardiovascular health, it follows that inhibition of GSNOR may be beneficial. However, the effect of GSNOR inhibition on vascular activity is unknown. To study the effects of GSNOR inhibition on endothelial function, we treated rats with a small-molecule inhibitor of GSNOR (N6338) that has vasodilatory effects on isolated aortic rings and assessed effects on arterial flowmediated dilation (FMD), an NO-dependent process. GSNOR inhibition with a single intravenous dose of N6338 preserved FMD (15.3 ± 5.4 vs. 14.2 ± 6.3%, P = nonsignificant) under partial NO synthase inhibition that normally reduces FMD by roughly 50% (14.1 ± 2.9 vs. 7.6 ± 4.4%, P < 0.05). In hypertensive rats, daily oral administration of N6338 for 14 days reduced blood pressure (170.0 ± 5.3/122.7 ± 6.4 vs. 203.8 ± 1.9/143.7 ± 7.5 mmHg for vehicle, P < 0.001) and vascular resistance index (1.5 ± 0.4 vs. 3.2 ± 1.0 mmHg·min·l-1 for vehicle, P < 0.001), and restored FMD from an initially impaired state (7.4 ± 1.7%, day 0) to a level (13.0 ± 3.1%, day 14, P < 0.001) similar to that observed in normotensive rats. N6338 also reversed the pathological kidney changes exhibited by the hypertensive rats. GSNOR inhibition preserves FMD under conditions of impaired NO production and protects against both microvascular and conduit artery dysfunction in a model of hypertension. Copyright © 2013 the American Physiological Society.
Clancy J.P.,University of Cincinnati |
Szczesniak R.D.,University of Cincinnati |
Ashlock M.A.,Cystic Fibrosis Foundation |
Ashlock M.A.,aTyr Pharma |
And 16 more authors.
PLoS ONE | Year: 2013
Intestinal current measurements (ICM) from rectal biopsies are a sensitive means to detect cystic fibrosis transmembrane conductance regulator (CFTR) function, but have not been optimized for multicenter use. We piloted multicenter standard operating procedures (SOPs) to detect CFTR activity by ICM and examined key questions for use in clinical trials. SOPs for ICM using human rectal biopsies were developed across three centers and used to characterize ion transport from non-CF and CF subjects (two severe CFTR mutations). All data were centrally evaluated by a blinded interpreter. SOPs were then used across four centers to examine the effect of cold storage on CFTR currents and compare CFTR currents in biopsies from one subject studied simultaneously either at two sites (24 hours post-biopsy) or when biopsies were obtained by either forceps or suction. Rectal biopsies from 44 non-CF and 17 CF subjects were analyzed. Mean differences (μA/cm2; 95% confidence intervals) between CF and non-CF were forskolin/IBMX=102.6(128.0 to 81.1), carbachol=96.3(118.7 to 73.9), forskolin/IBMX+carbachol=200.9(243.1 to 158.6), and bumetanide=-44.6 (-33.7 to -55.6) (P<0.005, CF vs non-CF for all parameters). Receiver Operating Characteristic curves indicated that each parameter discriminated CF from non-CF subjects (area under the curve of 0.94-0.98). CFTR dependent currents following 18-24 hours of cold storage for forskolin/IBMX, carbachol, and forskolin/IBMX+carbachol stimulation (n=17 non-CF subjects) were 44%, 47.5%, and 47.3%, respectively of those in fresh biopsies. CFTR-dependent currents from biopsies studied after cold storage at two sites simultaneously demonstrated moderate correlation (n=14 non-CF subjects, Pearson correlation coefficients 0.389, 0.484, and 0.533). Similar CFTR dependent currents were detected from fresh biopsies obtained by either forceps or suction (within-subject comparisons, n=22 biopsies from three non-CF subjects). Multicenter ICM is a feasible CFTR outcome measure that discriminates CF from non-CF ion transport, offers unique advantages over other CFTR bioassays, and warrants further development as a potential CFTR biomarker. © 2013 Clancy et al.
Taylor A.L.,Columbia University |
Sabolinski M.L.,N30 Pharmaceuticals |
Ziesche S.,Veterans Affairs Medical Center |
Ghali J.K.,Wayne State University |
And 3 more authors.
Journal of Cardiac Failure | Year: 2012
Background: Fixed-dose combined isosorbide dinitrate/hydralazine (FDC I/H) significantly improved outcomes in patients with advanced heart failure (HF) receiving background neurohormonal therapy in the African-American Heart Failure Trial (A-HeFT). In this analysis, we investigated treatment effects by age <65 or ≥65 years. Methods and Results: Time-to-event curves were produced by the Kaplan-Meier method. Hazard ratios were calculated with the Cox proportional hazards model. Baseline characteristics showed that patients ≥65 years old had less hypertensive and more ischemic HF, better quality of life (QoL) scores, higher plasma B-type natriuretic peptide and creatinine levels, and received less background neurohormonal therapy. Kaplan-Meier curves showed that FDC I/H improved mortality and event-free survival in elderly patients. The hazard ratios for mortality, first heart failure hospitalization, and event-free survival (both unadjusted and adjusted for baseline differences), were similar quantitatively and in direction of effect in both age groups. Conclusions: In A-HeFT, FDC I/H improved outcomes in HF patients aged <65 or ≥65 years, despite significant baseline differences between these age groups. Patients aged ≥65 years, a group at greater mortality risk, had the greatest survival benefit from FDC I/H. © 2012 Elsevier Inc. All rights reserved.
Cox A.G.,Harvard University |
Saunders D.C.,Harvard University |
Kelsey P.B.,Harvard University |
Conway A.A.,Harvard University |
And 13 more authors.
Cell Reports | Year: 2014
Toxic liver injury is a leading cause of liver failure and death because of the organ's inability to regenerate amidst massive cell death, and few therapeutic options exist. The mechanisms coordinating damage protection and repair are poorly understood. Here, we show that S-nitrosothiols regulate liver growth during development and after injury invivo; in zebrafish, nitric-oxide (NO) enhanced liver formation independently of cGMP-mediated vasoactive effects. After acetaminophen (APAP) exposure, inhibition of the enzymatic regulator S-nitrosoglutathione reductase (GSNOR) minimized toxic liver damage, increased cell proliferation, and improved survival through sustained activation of the cytoprotective Nrf2 pathway. Preclinical studies of APAP injury in GSNOR-deficient mice confirmed conservation of hepatoprotective properties of S-nitrosothiol signaling across vertebrates; a GSNOR-specific inhibitor improved liver histology and acted with the approved therapy N-acetylcysteine to expand the therapeutic time window and improve outcome. These studies demonstrate that GSNOR inhibitors will be beneficial therapeutic candidates for treating liver injury. © 2014 The Authors.
PubMed | The Broad Institute of MIT and Harvard, N30 Pharmaceuticals, Beth Israel Deaconess Medical Center, Case Western Reserve University and Harvard University
Type: Journal Article | Journal: Cell reports | Year: 2014
Toxic liver injury is a leading cause of liver failure and death because of the organs inability to regenerate amidst massive cell death, and few therapeutic options exist. The mechanisms coordinating damage protection and repair are poorly understood. Here, we show that S-nitrosothiols regulate liver growth during development and after injury invivo; in zebrafish, nitric-oxide (NO) enhanced liver formation independently of cGMP-mediated vasoactive effects. After acetaminophen (APAP) exposure, inhibition of the enzymatic regulator S-nitrosoglutathione reductase (GSNOR) minimized toxic liver damage, increased cell proliferation, and improved survival through sustained activation of the cytoprotective Nrf2 pathway. Preclinical studies of APAP injury in GSNOR-deficient mice confirmed conservation of hepatoprotective properties of S-nitrosothiol signaling across vertebrates; a GSNOR-specific inhibitor improved liver histology and acted with the approved therapy N-acetylcysteine to expand the therapeutic time window and improve outcome. These studies demonstrate that GSNOR inhibitors will be beneficial therapeutic candidates for treating liver injury.
Bullerjahn G.S.,Bowling Green State University |
Boyanapalli R.,N30 Pharmaceuticals |
Rozmarynowycz M.J.,Bowling Green State University |
McKay R.M.L.,Bowling Green State University
Advances in Biochemical Engineering/Biotechnology | Year: 2010
Due to their ubiquity in aquatic environments and their contribution to total biomass, especially in oligotrophic systems, cyanobacteria can be viewed as a proxy for primary productivity in both marine and fresh waters. In this chapter we describe the development and use of picocyanobacterial bioreporters to measure the bioavailability of nutrients that may constrain total photosynthesis in both lacustrine and marine systems. Issues pertaining to bioreporter construction, performance and field applications are discussed. Specifically, luminescent Synechococcus spp. and Synechocystis spp. bioreporters are described that allow the bioavailability of phosphorus, nitrogen and iron to be accurately measured in environmental samples. © Springer-Verlag Berlin Heidelberg 2010.