A Polyphenol-Rich Extract from Muscadine Grapes Prevents Hypertension-Induced Diastolic Dysfunction and Oxidative Stress

Muscadine grapes are abundant in dietary polyphenols, but their effect on hypertension-induced cardiac damage is limited. This study assessed whether a muscadine grape skin/seed extract supplement (MGES) prevents hypertension-induced cardiac damage and oxidative stress. Male Sprague Dawley rats were treated for four weeks with drinking water, angiotensin II (Ang II) to induce hypertension, MGES, or both Ang II and MGES. Cardiac function assessed by echocardiography showed that Ang II increased systolic blood pressure while MGES alone or in combination with Ang II had no effect. Ang II increased E/e′, an indicator of left ventricular filling pressure and diastolic dysfunction, by 41% compared to Control and co-treatment with MGES prevented the Ang II-mediated increase, suggesting that the extract attenuated hypertension-induced diastolic function. Ang II infusion increased urinary 8-hydroxy-2′-deoxyguanosine and cardiac 4-hydroxynonenal and malondialdehyde, which were prevented by the extract. The antioxidant enzymes catalase and superoxide dismutase 1 activity and mRNA were increased significantly in animals treated with MGES alone or in combination with Ang II, suggesting that the extract upregulates oxidative stress defense mechanisms in cardiac tissue. Thus, MGES may serve as a medical food to protect the heart from hypertension-induced diastolic dysfunction caused in part by excessive reactive oxygen species production.

Abstract P3052: A Muscadine Grape Extract Improves Hypertension-Induced Aortic Damage in Conjunction With a Reduction in Fibrosis, Oxidative Stress, and Inflammation

Hypertension-induced arterial stiffness contributes to both reduced vascular and cardiac function. While the pathophysiology of aortic stiffness is not completely understood, significant vascular remodeling occurs in response to stimuli such as vascular stress and Ang II. The goal of this study was to determine whether a polyphenol-enriched muscadine grape skin and seed extract (MGE) improves Ang II-induced aortic remodeling. Sprague-Dawley rats (male, 8 weeks old) received normal drinking water (Control), 0.2 mg total phenolics/mL in their drinking water (MGE), 24 μg/kg/h of Ang II via osmotic minipump (Ang II), or both Ang II and MGE (Ang II/MGE, pre-treated with MGE for 1 week prior to Ang II treatment). MGE had no effect on systolic blood pressure, measured by tail cuff plethysmography, in normotensive or Ang II-treated rats. Aortic stiffness, determined by echocardiographic pulse wave velocity, was increased 2.5-fold in Ang II-treated animals but was significantly improved by co-administration of MGE. MGE prevented the Ang II-induced increase in aortic media thickness (Control: 95.8 ± 2.1 μm, Ang II: 135.1 ± 3.7 μm, and Ang II/MGE: 118.2 ± 2.9 μm) and lumen diameter (Control: 2.7 ± 0.2, Ang II: 2.1 ± 0.1 mm, and Ang II/MGE: 2.6 ± 0.1 mm). Nuclear phosphorylated ERK (pERK) in aortic medial cells was increased by 131% in Ang II-treated rats compared to Controls (p < 0.05); MGE co-administration prevented this by 83% (p < 0.001). Ang II-induced aortic fibrosis, measured by total collagen and collagen III, was significantly attenuated in hypertensive animals treated with MGE, in association with reduced pSMAD2 and CTGF. 4-HNE, a marker of lipid peroxidation, and subunits of NADPH oxidases--Nox1, Nox2, p-p47phox--were significantly upregulated by Ang II and normalized with MGE. The inflammatory markers IL-6 and NF-κB were also increased in Ang II-treated aortas (8.9- and 12.7-fold, respectively) and attenuated by MGE. This study is the first to demonstrate that Ang II-induced vascular remodeling is prevented by co-administration of MGE. MGE reduced aortic stiffness, in association with a decrease in fibrotic, oxidative stress, and inflammatory signaling, suggesting that MGE supplementation may improve vascular function in hypertensive patients.

Development of Squamous Cell Carcinoma After Pulmonary Aspergillosis in the Native Lung of a Lung Transplant Recipient: A Case Report

Lung transplant recipients have a significant incidence of posttransplant lung nodules. Such nodules can occur from various etiologies, both in the lung allograft or in the native lung. They most commonly originate from infections, such as Pseudomonas or Aspergillus species, or from posttransplant lymphoproliferative disorder. Lung cancer is challenging to diagnose in a native lung, especially with an underlying fibrotic disease. We present a case of a 75-year-old woman who presented with classic clinical features of pulmonary aspergillosis in the native right lung with idiopathic pulmonary fibrosis 5 years after left-sided single-lung transplant. She required a right lower lobectomy and antifungal treatment with isavuconazonium sulfate and inhaled amphotericin. A persistent right upper lobe lung nodule was noted during surveillance imaging and was initially presumed to be recurrent Aspergillus infection; however, growth of the nodule and change in its characteristics prompted additional examination. A navigational bronchoscopic biopsy was positive for squamous cell carcinoma. Her options for stage IIIA squamous cell carcinoma were limited to chemotherapy with paclitaxel and carboplatin plus radiation. Although initial surveillance scans showed adequate tumor response, metastatic squamous cell carcinoma was found in the liver 6 months later. She was eventually transitioned to palliative care. This case highlights the importance of a high index of suspicion for examination of nodules in the native lung of lung transplant recipients, even in cases of a known diagnosis, owing to the high morbidity and mortality associated with primary lung cancer in this population.

Abstract P193: Anti-fibrotic and Anti-oxidant Actions of a Muscadine Grape Extract Supplement on Hypertension-induced Cardiac Damage

Approximately 75 million U.S. adults suffer from hypertension, an independent risk factor for pathological cardiac hypertrophy. The current study examines the effects of a muscadine grape extract formulation (MGE; Piedmont Research & Development Corp.) with anti-oxidant, anti-inflammatory, and anti-proliferative properties on hypertension-induced cardiac damage in Sprague-Dawley rats receiving a 4-week Ang II infusion (24 μg/kg/h). We previously showed that MGE in the drinking water had no effect on blood pressure or systolic function in normotensive or hypertensive rats; however, MGE ameliorated the Ang II-induced decrease in diastolic function and increase in cardiomyocyte cross-sectional area. In the current study, MGE supplementation of Ang II-treated rats decreased interstitial cardiac fibrosis, reducing collagen III staining in the myocardium (0.9 ± 0.2% control, 6.8 ± 1.0% Ang II, and 2.8 ± 0.4% Ang II/MGE; p<0.01). MGE alone had no effect on any parameters assessed. The positive correlation between collagen and diastolic function with Ang II compared to control (p<0.01) was significantly abrogated by co-administration of MGE. TGFβ is a critical cytokine that stimulates cardiac fibrosis. The Ang II-mediated increase in cardiac TGFβ mRNA was attenuated by MGE (relative gene expression: 1.0 ± 0.1 control, 2.0 ± 0.4 Ang II, 1.1 ± 0.2 Ang II/MGE; p<0.05) as was downstream pSmad2 protein in cardiomyocytes (% nuclei: 26.1 ± 6 control, 53.8 ± 9.6 Ang II, 27.6 ± 5.5 Ang II/MGE; p<0.05) and cardiac fibroblasts (2.3 ± 1.1 control, 11.7 ± 4.9 Ang II, 2.2 ± 0.5 Ang II/MGE; p<0.05). NADPH oxidase is a primary contributor to cardiac oxidative stress and excess ROS production can lead to activation of pro-fibrotic pathways. MGE significantly reduced the Ang II-induced increase in p22phox mRNA (relative gene expression: 1.0 ± 0.1 control, 1.9 ± 0.1 Ang II, 1.0 ± 0.1 Ang II/MGE; p<0.0001) and protein (relative density: 1.0 ± 0.2 control, 5.4 ± 1.6 Ang II, 2.9 ± 1.0 Ang II/MGE; p<0.05), a subunit required for NADPH oxidase activity. These results indicate that MGE ameliorates cardiac fibrosis by targeting NADPH oxidase and the TGFβ pro-fibrotic pathway, suggesting that MGE supplementation may be an effective, natural therapeutic for hypertension-induced cardiac damage.

InlA promotes dissemination of Listeria monocytogenes to the mesenteric lymph nodes during food borne infection of mice

Intestinal Listeria monocytogenes infection is not efficient in mice and this has been attributed to a low affinity interaction between the bacterial surface protein InlA and E-cadherin on murine intestinal epithelial cells. Previous studies using either transgenic mice expressing human E-cadherin or mouse-adapted L. monocytogenes expressing a modified InlA protein (InlA(m)) with high affinity for murine E-cadherin showed increased efficiency of intragastric infection. However, the large inocula used in these studies disseminated to the spleen and liver rapidly, resulting in a lethal systemic infection that made it difficult to define the natural course of intestinal infection. We describe here a novel mouse model of oral listeriosis that closely mimics all phases of human disease: (1) ingestion of contaminated food, (2) a distinct period of time during which L. monocytogenes colonize only the intestines, (3) varying degrees of systemic spread in susceptible vs. resistant mice, and (4) late stage spread to the brain. Using this natural feeding model, we showed that the type of food, the time of day when feeding occurred, and mouse gender each affected susceptibility to L. monocytogenes infection. Co-infection studies using L. monocytogenes strains that expressed either a high affinity ligand for E-cadherin (InlA(m)), a low affinity ligand (wild type InlA from Lm EGDe), or no InlA (ΔinlA) showed that InlA was not required to establish intestinal infection in mice. However, expression of InlA(m) significantly increased bacterial persistence in the underlying lamina propria and greatly enhanced dissemination to the mesenteric lymph nodes. Thus, these studies revealed a previously uncharacterized role for InlA in facilitating systemic spread via the lymphatic system after invasion of the gut mucosa.