Cannon Research Center

Pumpkin Center, NC, United States

Cannon Research Center

Pumpkin Center, NC, United States
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Chalasani N.,Indiana University | Vuppalanchi R.,Indiana University | Navarro V.,Thomas Jefferson University | Fontana R.,Alfred University | And 4 more authors.
Annals of Internal Medicine | Year: 2012

Background: Flavocoxid is a prescription medical food that is used to treat osteoarthritis. It is a proprietary blend of 2 flavonoids, baicalin and catechins, which are derived from the botanicals Scutellaria baicalensis and Acacia catechu, respectively. Objective: To describe characteristics of patients with acute liver injury suspected of being caused by flavocoxid. Design: Case series. Setting: Drug-Induced Liver Injury Network Prospective Study ongoing at multiple academic medical centers since 2004. Patients: Four adults with liver injury. Measurements: Clinical characteristics, liver biochemistry values, and outcomes. Results: Among 877 patients enrolled in the prospective study, 4 had liver injury suspected to have been caused by flavocoxid. All were women; ages ranged from 57 to 68 years. All developed symptoms and signs of liver injury within 1 to 3 months after initiating flavocoxid. Liver injury was characterized by marked elevations in levels of alanine aminotransferase (mean peak, 1268 U/L; range, 741 to 1540 U/L), alkaline phosphatase (mean peak, 510 U/L; range, 286 to 770 U/L), and serum bilirubin (mean peak, 160.7 μmol/L [9.4 mg/dL]; range, 34.2 to 356 μmol/L [2.0 to 20.8 mg/dL]). Liver biochemistry values decreased to the normal range within 3 to 12 weeks after flavocoxid was stopped, and all patients recovered without experiencing acute liver failure or chronic liver injury. Causality was adjudicated as highly likely in 3 patients and as possible in 1 patient. Limitation: The frequency and mechanism of liver injury could not be assessed. Conclusion: Flavocoxid can cause clinically significant liver injury, which seems to resolve within weeks after cessation. Primary Funding Source: National Institute of Diabetes and Digestive and Kidney Diseases. © 2012 American College of Physicians.

Knab A.M.,Appalachian State University | Bowen R.S.,Truett-McConnell College | Hamilton A.T.,Cannon Research Center | Lightfoot J.T.,Texas A&M University
Journal of Biological Regulators and Homeostatic Agents | Year: 2012

The genetic factors involved in the regulation of physical activity are not well understood. The dopamine system has been implicated in the control of voluntary locomotion and wheel running (WR) in mice and is thus a likely candidate as a genetic/biological system important to the regulation of physical activity. This study evaluated the effects of four different dopaminergic acting drugs on WR in differentially active inbred strains of mice. High active C57L/J (n=7, 3 controls, 4 experimental) and low active C3H/HeJ (n=8, 3 controls, 5 experimental) were analyzed for baseline wheel-running indices of distance (km/day), duration (mins/day), and speed (m/min) for 21 days. Experimental mice received increasing doses over four days of each of the following drugs: SKF 81297 (Dl agonist), SCH 23390 (Dl antagonist), GBR 12783 (DAT inhibitor), and AMPT (tyrosine hydroxylase inhibitor). Each drug dose response treatment was separated by three days of recovery (no drug injections). WR indices were monitored during drug treatments and during drug wash-out phases. SKF 81297 significantly reduced (p=0.0004) WR in the C57L/J mice, but did not affect WR in the C3H/HeJ mice. GBR 12783 significantly increased (p=0.0005) WR in C3H/HeJ mice, but did not affect WR in C57L/J mice. Only duration (not overall WR) was significantly reduced in C57L/J mice in response to SCH 23390 (p=0.003) and AMPT (p=0.043). SCH 23390 (p=0.44) and AMPT (p=0.98) did not significantly affect WR in C3H/HeJ mice. These results suggest that genetic differences in dopamine signaling may play a role in the WR response to dopaminergic-acting drugs in inbred strains of mice. The high activity in the C57L/J strain appears most responsive to D1-like receptor acting drugs, while in the C3H/HeJ strain, dopamine re-uptake appears to have an influence on activity level. Copyright © by BIOLIFE, s.a.s.

Li T.,Cannon Research Center | Eheim A.L.,Cannon Research Center | Eheim A.L.,German Cancer Research Center | Klein S.,University of Bonn | And 7 more authors.
Hepatology | Year: 2014

Hepatic stellate cell (HSC) transdifferentiation from a quiescent, adipocyte-like cell to a highly secretory and contractile myofibroblast-like phenotype contributes to negative pathological consequences, including fibrosis/cirrhosis with portal hypertension (PH). Antiadipogenic mechanisms have been shown to underlie activation of HSCs. We examined the role of heme-sensing nuclear receptor Rev-erbα, a transcriptional repressor involved in metabolic and circadian regulation known to promote adipogenesis in preadipocytes, in HSC transdifferentiation. We discovered that Rev-erbα protein was up-regulated in activated HSCs and injured livers; however, transcriptional repressor activity was not affected by fibrogenic treatments. Surprisingly, increased protein expression was accompanied with increased cytoplasmic accumulation of Rev-erbα, which demonstrated distributions similar to myosin, the major cellular motor protein. Cells overexpressing a cytoplasm-localized Rev-erbα exhibited enhanced contractility. Ectopically expressed Rev-erbα responded to both adipogenic ligand and fibrogenic transforming growth factor beta treatment. Rev-erb ligand SR6452 down-regulated cytoplasmic expression of Rev-erbα, decreased expression of fibrogenic markers and the activated phenotype in HSCs, and ameliorated fibrosis and PH in rodent models. Conclusions: Up-regulation of Rev-erbα is an intrinsic fibrogenic response characterized by cytoplasmic accumulation of the protein in activated HSCs. Cytoplasmic expression of Rev-erbα promotes a contractile phenotype. Rev-erbα acts as a bifunctional regulator promoting either anti- or profibrogenic response, depending on milieu. Rev-erb ligand SR6452 functions by a previously undescribed mechanism, targeting both nuclear activity and cytoplasmic expression of Rev-erbα. Our studies identify Rev-erbα as a novel regulator of HSC transdifferentiation and offers exciting new insights on the therapeutic potential of Rev-erb ligands. © 2014 by the American Association for the Study of Liver Diseases.

Navarro V.J.,Albert Einstein Medical Center | Bonkovsky H.L.,Medicine and Research | Hwang S.-I.,Cannon Research Center | Vega M.,Albert Einstein Medical Center | And 2 more authors.
Digestive Diseases and Sciences | Year: 2013

Background: Many herbal dietary supplements (HDS) contain green tea extract (GTE) and its component catechins, although their presence may not always be indicated on the product label. Purpose: Because GTE and catechins have been implicated in human hepatotoxicity in several case reports, our objective was to determine whether catechins were present in HDS that were implicated in hepatotoxicity, even if not identified among the labeled ingredients, and whether these compounds could be associated with liver injury. Methods: We assayed 97 HDS implicated in human hepatotoxicity for catechins. Results: We found that 29 of 73 HDS (39.7 %) that did not identify GTE or any of its component catechins on their label contained catechins. Among patients with confirmed hepatotoxicity, there was no statistically significant association between the presence of catechin or the dose consumed and liver injury causality score, severity, or pattern of liver injury. Catechin levels tended to be highest in products used for weight loss, although catechin concentrations were low in most products. Conclusions: Many HDS commonly contain catechins that are implicated in hepatotoxicity, although their presence may not be indicated on the product label. Although our results did not establish an association between GTE or catechins with hepatotoxicity, they highlight some of the many complexities and uncertainties that surround the attribution of drug-induced liver injury (DILI) to HDS. © 2013 Springer Science+Business Media New York.

Ghabril M.,Indiana University | Bonkovsky H.L.,Cannon Research Center | Kum C.,California Pacific Medical Center | Davern T.,California Pacific Medical Center | And 6 more authors.
Clinical Gastroenterology and Hepatology | Year: 2013

Background & Aims: Tumor necrosis factor (TNF)-α antagonists have been associated with drug-induced liver injury (DILI). We reviewed cases of DILI in the United States to identify those associated with use of TNF-α antagonists. Methods: We searched the U.S. DILI Network (DILIN) database, from 2003 to 2011, for cases associated with TNF-α antagonists. Mean Roussel-Uclaf Causality Assessment Method scores were calculated. A DILIN severity score was assigned according to a previously published scale, and we identified 6 subjects likely to have DILI associated with use of TNF-α antagonists. We also searched PubMed for articles that reported hepatotoxicity from TNF-α antagonists, identifying 28 additional cases suitable for analysis. Results: The drugs presumed to have caused DILI were infliximab (n = 26), etanercept (n = 4), and adalimumab (n = 4). The anti-TNF-α agent was the probable cause of 12 cases of DILI (35%), a very likely cause for 21 (62%), and a definite cause for 1 (3%). Median latency was 13 weeks (range, 2-104); however, 7 cases (20%) had latency periods longer than 24 weeks. Twenty-two of 33 subjects who underwent serologic analysis (67%) tested positive for anti-nuclear and/or smooth muscle antibodies. Of these 22, 17 underwent liver biopsy; 15 subjects had clear features of autoimmunity. The 22 subjects with autoimmune features had longer median latency (16 vs 10 weeks) and higher peak levels of alanine aminotransferase (784 vs 528 U/L) than the 12 without such features. There was 1 case of severe cholestasis. All but one subject improved after discontinuation of the implicated drug; 12 subjects received corticosteroid therapy. No deaths were attributed to liver injury, although one patient with preexistent cirrhosis required liver transplantation. Conclusions: Acute liver injury caused by TNF-α antagonists may be a class effect because multiple agents in this category have been implicated. The most common presentation is an autoimmune phenotype with marked hepatocellular injury, but a mixed non-autoimmune pattern or predominant cholestasis also occurs. The prognosis is usually good after drug discontinuation, although some patients may benefit from a course of corticosteroids. Number, NCT00345930. © 2013 AGA Institute.

Lambrecht R.W.,University of Connecticut Health Center | Sterling R.K.,Virginia Commonwealth University | Naishadham D.,New England Research Institutes, Inc. | Stoddard A.M.,New England Research Institutes, Inc. | And 6 more authors.
Gastroenterology | Year: 2011

Background & Aims: Iron may influence severity and progression of non-hemochromatotic liver diseases. Our aim was to assess the relationship of iron and HFE genetic variations to progression and outcomes in the HALT-C Trial and whether PegIFN therapy influenced iron variables. Methods: Participants were randomized to receive long-term PegIFN [n = 400] or no therapy [n = 413] for 3.5 y, with follow-up for up to 8.7 y [median 6.0 y]. Associations of patient characteristics with iron variables at baseline and over time were carried out using Kaplan-Meier analyses, Cox regression models, and repeated measures analysis of covariance. Results: Participants who developed clinical outcomes [CTP > 7, ascites, encephalopathy, variceal bleeding, SBP, HCC, death] had significantly higher baseline scores for stainable iron in hepatocytes and in portal tract cells than those without. There were significant direct correlations between stainable iron in portal triads and lobular and total Ishak inflammatory and fibrosis scores [P < 0.0001]. Iron in triads at baseline increased risk of outcomes (HR = 1.35, P = 0.02). Stainable iron in hepatocytes decreased, whereas that in portal stromal cells increased significantly [P < 0.0001] over time. Serum iron and TIBC fell significantly over time [P < 0.0001], as did serum ferritin [P = 0.0003]. Chronic PegIFN treatment did not affect stainable iron. HFE genetic variations did not correlate with outcomes, including development of hepatocellular carcinoma. Conclusions: Stainable iron in hepatocytes and portal tract cells is a predictor of progression and clinical and histological outcomes in advanced chronic hepatitis C. Chronic low-dose PegIFN therapy did not improve outcomes, nor iron variables. © 2011 AGA Institute.

Katz M.G.,Sanger Heart and Vascular Institute | Fargnoli A.S.,Sanger Heart and Vascular Institute | Williams R.D.,Sanger Heart and Vascular Institute | Steuerwald N.M.,Cannon Research Center | And 4 more authors.
Journal of Thoracic and Cardiovascular Surgery | Year: 2014

Objective Therapeutic safety and efficacy are the basic prerequisites for clinical gene therapy. We investigated the effect of high-dose molecular cardiac surgery with recirculating delivery (MCARD)-mediated adeno-associated virus 9 (AAV9)/sarcoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA2a) gene delivery on clinical parameters, oxidative stress, humoral and cellular immune responses, and cardiac remodeling. Methods Ischemic cardiomyopathy was generated in a sheep model. The sheep were assigned to 1 of 2 groups: control (n = 10) and study (MCARD, n = 6). The control group underwent no intervention and the study group received 1014 genome copies of AAV9/SERCA2a 4 weeks after infarction. Results Our ischemic model produced reliable infarcts leading to heart failure. The baseline ejection fraction in the MCARD group was 57.6% ± 1.6% versus 61.2% ± 1.9% in the control group (P >.05). At 12 weeks after infarction, the MCARD group had superior left ventricular function compared with the control group: stroke volume index, 46.6 ± 1.8 versus 35.8 ± 2.5 mL/m2 (P <.05); ejection fraction, 46.2% ± 1.9% versus 38.7% ± 2.5% (P <.05); and left ventricular end-systolic and end-diastolic dimensions, 41.3 ± 1.7 versus 48.2 ± 1.4 mm and 51.2 ± 1.5 versus 57.6 ± 1.7 mm, respectively (P <.05). The markers of oxidative stress were significantly reduced in the infarct zone in the MCARD group. No positive T-cell-mediated immune response was seen in the MCARD group at any point. Myocyte hypertrophy was also significantly attenuated in the MCARD group compared with the control group. Conclusions Cardiac overexpression of the SERCA2a gene by way of MCARD is a safe therapeutic intervention. It significantly improves left ventricular function, decreases markers of oxidative stress, abrogates myocyte hypertrophy, arrests remodeling, and does not induce a T-cell-mediated immune response. © 2014 by The American Association for Thoracic Surgery.

Li T.,Cannon Research Center | Bonkovsky H.L.,Cannon Research Center | Bonkovsky H.L.,University of North Carolina at Charlotte | Bonkovsky H.L.,University of North Carolina at Chapel Hill | And 2 more authors.
BMC Structural Biology | Year: 2011

Background: Heme is an essential molecule and plays vital roles in many biological processes. The structural determination of a large number of heme proteins has made it possible to study the detailed chemical and structural properties of heme binding environment. Knowledge of these characteristics can provide valuable guidelines in the design of novel heme proteins and help us predict unknown heme binding proteins. Results: In this paper, we constructed a non-redundant dataset of 125 heme-binding protein chains and found that these heme proteins encompass at least 31 different structural folds with all- class as the dominating scaffold. Heme binding pockets are enriched in aromatic and non-polar amino acids with fewer charged residues. The differences between apo and holo forms of heme proteins in terms of the structure and the binding pockets have been investigated. In most cases the proteins undergo small conformational changes upon heme binding. We also examined the CP (cysteine-proline) heme regulatory motifs and demonstrated that the conserved dipeptide has structural implications in protein-heme interactions. Conclusions: Our analysis revealed that heme binding pockets show special features and that most of the heme proteins undergo small conformational changes after heme binding, suggesting the apo structures can be used for structure-based heme protein prediction and as scaffolds for future heme protein design. © 2011 Li et al; licensee BioMed Central Ltd.

Marshburn P.B.,Carolinas Healthcare System | Giddings A.,Carolinas Healthcare System | Causby S.,Carolinas Healthcare System | Matthews M.L.,Carolinas Healthcare System | And 3 more authors.
Fertility and Sterility | Year: 2014

Objective To determine whether the period of ejaculatory abstinence (EA) influences the total antioxidant capacity (TAC) of semen or lipid peroxidation (LPO) of sperm membranes. Design A prospective experimental trial. Setting Academic medical center for reproductive endocrinology and infertility. Patient(s) Forty men from infertile couples planning intrauterine insemination. Intervention(s) Men provided semen specimens after EA periods of 1 and 4 days. Main Outcome Measure(s) Semen analysis, peroxidase staining, and assays for seminal TAC and sperm membrane LPO, with measures compared between days 1 and 4 within individuals (internal control) using paired t tests. Result(s) The shorter period of EA (1 day vs. 4 days) resulted in statistically significant decreases in semen volume (-24%), sperm density (-28%), and total sperm count (-3.2%). There was a statistically significant increase in TAC with the shorter period of EA (1 day) compared with 4 days of EA. No difference was detected in sperm membrane LPO comparing 1 day of EA and 4 days of EA. Conclusion(s) Higher seminal TAC obtained after a shorter period of EA could diminish oxidative stress-induced sperm damage by a mechanism independent of LPO. Shorter periods of EA may thus improve sperm quality by protecting from reactive oxygen species damage, even though lower numbers of motile sperm are produced after a shorter period of EA. This would be consistent with prior research indicating improved results after intrauterine insemination under these circumstances. © 2014 by the American Congress of Rehabilitation Medicine.

Yan J.,University of Manitoba | Gong Y.,University of Manitoba | Wang G.,Cannon Research Center | Gang Y.,University of Manitoba | Burczynski F.J.,University of Manitoba
Biochemistry and Cell Biology | Year: 2010

Peroxisome proliferator-activated receptor (PPAR) agonists such as clofibrate are known to affect liver fatty acid binding protein (L-FABP) levels, which in turn influence hepatocellular oxidant status. The mechanism of clofibrate's modulation of L-FABP levels is not clear. In this study we used clofibrate (PPARα agonist), MK886 (PPARα antagonist), and GW9662 (PPARγ antagonist) in determining the regulating mechanism of L-FABP expression and its antioxidant activity in CRL-1548 hepatoma cells. Antioxidant activity was assessed by determining intracellular reactive oxygen species (ROS) using dichlorofluorescein (DCF) fluorescence. The effect of clofibrate on cytosolic activity of the intracellular antioxidant enzymes was also assessed. RT-PCR and mRNA stability assay showed that clofibrate treatment enhanced L-FABP mRNA stability, which resulted in increased L-FABP levels. A nuclear run-off assay and RT-PCR measurements of L-FABP mRNA revealed that clofibrate increased the L-FABP gene transcription rate. The increased L-FABP was associated with reduced cytosolic ROS. Levels of superoxide dismutase, glutathione peroxidase, and catalase were not affected by clofibrate treatment. L-FABP siRNA knockdown studies showed that a reduction in L-FABP expression was associated with increased DCF fluorescence. We conclude that clofibrate enhanced L-FABP gene transcription and mRNA stability, thus affecting L-FABP expression and ultimately cellular antioxidant activity.

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