48 results on '"Yohannes T"'
Search Results
2. Computational approaches for drug repurposing in oncology: untapped opportunity for high value innovation.
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Dalwadi, Shraddha M., Hunt, Andrew, Bonnen, Mark D., and Ghebre, Yohannes T.
- Abstract
Historically, the effort by academia and industry to develop new chemical entities into lifesaving drugs has limited success in meeting the demands of today's healthcare. Repurposing drugs that are originally approved by the United States Food and Drug Administration or by regulatory authorities around the globe is an attractive strategy to rapidly develop much-needed therapeutics for oncologic indications that extend from treating cancer to managing treatment-related complications. This review discusses computational approaches to harness existing drugs for new therapeutic use in oncology. [ABSTRACT FROM AUTHOR]
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- 2023
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3. The inside scoop: Comparative genomics of two intranuclear bacteria, "Candidatus Berkiella cookevillensis" and "Candidatus Berkiella aquae".
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Kidane, Destaalem T., Mehari, Yohannes T., Rice, Forest C., Arivett, Brock A., Gunderson, John H., Farone, Anthony L., and Farone, Mary B.
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CANDIDATUS ,AMINO acid synthesis ,GRAM-negative bacteria ,SECRETION ,BACTERIA ,GENOME size ,COMPARATIVE genomics - Abstract
"Candidatus Berkiella cookevillensis" (strain CC99) and "Candidatus Berkiella aquae" (strain HT99), belonging to the Coxiellaceae family, are gram-negative bacteria isolated from amoebae in biofilms present in human-constructed water systems. Both bacteria are obligately intracellular, requiring host cells for growth and replication. The intracellular bacteria-containing vacuoles of both bacteria closely associate with or enter the nuclei of their host cells. In this study, we analyzed the genome sequences of CC99 and HT99 to better understand their biology and intracellular lifestyles. The CC99 genome has a size of 2.9Mb (37.9% GC) and contains 2,651 protein-encoding genes (PEGs) while the HT99 genome has a size of 3.6Mb (39.4% GC) and contains 3,238 PEGs. Both bacteria encode high proportions of hypothetical proteins (CC99: 46.5%; HT99: 51.3%). The central metabolic pathways of both bacteria appear largely intact. Genes for enzymes involved in the glycolytic pathway, the non-oxidative branch of the phosphate pathway, the tricarboxylic acid pathway, and the respiratory chain were present. Both bacteria, however, are missing genes for the synthesis of several amino acids, suggesting reliance on their host for amino acids and intermediates. Genes for type I and type IV (dot/icm) secretion systems as well as type IV pili were identified in both bacteria. Moreover, both bacteria contain genes encoding large numbers of putative effector proteins, including several with eukaryotic-like domains such as, ankyrin repeats, tetratricopeptide repeats, and leucine-rich repeats, characteristic of other intracellular bacteria. [ABSTRACT FROM AUTHOR]
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- 2022
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4. Combination of esomeprazole and pirfenidone enhances antifibrotic efficacy in vitro and in a mouse model of TGFβ-induced lung fibrosis.
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Ebrahimpour, Afshin, Ahir, Manisha, Wang, Min, Jegga, Anil G., Bonnen, Mark D., Eissa, N. Tony, Montesi, Sydney B., Raghu, Ganesh, and Ghebre, Yohannes T.
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MYOFIBROBLASTS ,LUNGS ,PULMONARY fibrosis ,IDIOPATHIC pulmonary fibrosis ,ESOMEPRAZOLE ,LABORATORY mice ,ANIMAL disease models - Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease of unknown etiology. Currently, pirfenidone and nintedanib are the only FDA-approved drugs for the treatment of IPF and are now the standard of care. This is a significant step in slowing down the progression of the disease. However, the drugs are unable to stop or reverse established fibrosis. Several retrospective clinical studies indicate that proton pump inhibitors (PPIs; FDA-approved to treat gastroesophageal reflux) are associated with favorable outcomes in patients with IPF, and emerging preclinical studies report that PPIs possess antifibrotic activity. In this study, we evaluated the antifibrotic efficacy of the PPI esomeprazole when combined with pirfenidone in vitro and in vivo. In cell culture studies of IPF lung fibroblasts, we assessed the effect of the combination on several fibrosis-related biological processes including TGFβ-induced cell proliferation, cell migration, cell contraction, and collagen production. In an in vivo study, we used mouse model of TGFβ-induced lung fibrosis to evaluate the antifibrotic efficacy of esomeprazole/pirfenidone combination. We also performed computational studies to understand the molecular mechanisms by which esomeprazole and/or pirfenidone regulate lung fibrosis. We found that esomeprazole significantly enhanced the anti-proliferative effect of pirfenidone and favorably modulated TGFβ-induced cell migration and contraction of collagen gels. We also found that the combination significantly suppressed collagen production in response to TGFβ in comparison to pirfenidone monotherapy. In addition, our animal study demonstrated that the combination therapy effectively inhibited the differentiation of lung fibroblasts into alpha smooth muscle actin (αSMA)-expressing myofibroblasts to attenuate the progression of lung fibrosis. Finally, our bioinformatics study of cells treated with esomeprazole or pirfenidone revealed that the drugs target several extracellular matrix (ECM) related pathways with esomeprazole preferentially targeting collagen family members while pirfenidone targets the keratins. In conclusion, our cell biological, computational, and in vivo studies show that the PPI esomeprazole enhances the antifibrotic efficacy of pirfenidone through complementary molecular mechanisms. This data supports the initiation of prospective clinical studies aimed at repurposing PPIs for the treatment of IPF and other fibrotic lung diseases where pirfenidone is prescribed. [ABSTRACT FROM AUTHOR]
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- 2022
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5. Proton pump inhibitors and sensitization of cancer cells to radiation therapy.
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Hebert, Kassidy A., Bonnen, Mark D., and Ghebre, Yohannes T.
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This review article outlines six molecular pathways that confer resistance of cancer cells to ionizing radiation, and describes how proton pump inhibitors (PPIs) may be used to overcome radioresistance induced by alteration of one or more of these signaling pathways. The inflammatory, adaptive, hypoxia, DNA damage repair, cell adhesion, and developmental pathways have all been linked to the resistance of cancer cells to ionizing radiation. Here we describe the molecular link between alteration of these pathways in cancer cells and development of resistance to ionizing radiation, and discuss emerging data on the use of PPIs to favorably modify one or more components of these pathways to sensitize cancer cells to ionizing radiation. Understanding the relationship between altered signaling pathways, radioresistance, and biological activity of PPIs may serve as a basis to repurpose PPIs to restore key biological processes that are involved in cancer progression and to sensitize cancer cells to radiation therapy. [ABSTRACT FROM AUTHOR]
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- 2022
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6. Inhibition of RUNX1 blocks the differentiation of lung fibroblasts to myofibroblasts.
- Author
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Dubey, Shubham, Dubey, Praveen K., Umeshappa, Channakeshava S., Ghebre, Yohannes T., and Krishnamurthy, Prasanna
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RUNX proteins ,MYOFIBROBLASTS ,IDIOPATHIC pulmonary fibrosis ,FIBROBLASTS ,RNA-binding proteins - Abstract
Pathological fibrosis contributes to progression of various diseases, for which the therapeutic options are limited. Idiopathic pulmonary fibrosis (IPF) is one such progressive and fatal interstitial fibrotic disease that is often characterized by excessive accumulation of extracellular matrix (ECM) proteins leading to stiff lung tissue and impaired gas exchange. However, the molecular mechanisms underlying IPF progression remain largely unknown. In this study, we determined the role of Runt‐related transcription factor 1 (RUNX1), an evolutionarily conserved transcription factor, in the differentiation of human lung fibroblasts (HLFs) in vitro and in an animal model of bleomycin (BLM)‐induced lung fibrosis. We observed that the expression of RUNX1 was significantly increased in the lungs of BLM‐injected mice as compared to saline‐treated mice. Furthermore, HLFs stimulated with transforming growth factor β (TGF‐β) showed significantly higher RUNX1 expression at both mRNA and protein levels, and compartmentalization in the nucleus. Inhibition of RUNX1 in HLFs (using siRNA) showed a significant reduction in the differentiation of fibroblasts into myofibroblasts as evidenced by reduced expression of alpha‐smooth muscle actin (α‐SMA), TGF‐β and ECM proteins such as fibronectin 1 (FN1), and collagen 1A1 (COL1A1). Mechanistic studies revealed that the increased expression of RUNX1 in TGF‐β‐stimulated lung fibroblasts is due to enhanced mRNA stability of RUNX1 through selective interaction with the RNA‐binding profibrotic protein, human antigen R (HuR). Collectively, our data demonstrate that increased expression of RUNX1 augments processes involved in lung fibrosis including the differentiation of fibroblasts into collagen‐synthesizing myofibroblasts. Our study suggests that targeting RUNX1 could limit the progression of organ fibrosis in diseases characterized by abnormal collagen deposition. [ABSTRACT FROM AUTHOR]
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- 2022
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7. Esomeprazole attenuates inflammatory and fibrotic response in lung cells through the MAPK/Nrf2/HO1 pathway.
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Ebrahimpour, Afshin, Wang, Min, Li, Li, Jegga, Anil G., Bonnen, Mark D., Eissa, N. Tony, Raghu, Ganesh, Jyothula, Soma, Kheradmand, Farrah, Hanania, Nicola A., Rosas, Ivan O., and Ghebre, Yohannes T.
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PULMONARY fibrosis ,IDIOPATHIC pulmonary fibrosis ,ESOMEPRAZOLE ,TRANSFORMING growth factors ,INFLAMMATION ,HEME oxygenase ,GENE expression profiling - Abstract
Introduction: Idiopathic pulmonary fibrosis (IPF) is an orphan disease characterized by progressive loss of lung function resulting in shortness of breath and often death within 3–4 years of diagnosis. Repetitive lung injury in susceptible individuals is believed to promote chronic oxidative stress, inflammation, and uncontrolled collagen deposition. Several preclinical and retrospective clinical studies in IPF have reported beneficial outcomes associated with the use of proton pump inhibitors (PPIs) such as esomeprazole. Accordingly, we sought to investigate molecular mechanism(s) by which PPIs favorably regulate the disease process. Methods: We stimulated oxidative stress, pro-inflammatory and profibrotic phenotypes in primary human lung epithelial cells and fibroblasts upon treatment with bleomycin or transforming growth factor β (TGFβ) and assessed the effect of a prototype PPI, esomeprazole, in regulating these processes. Results: Our study shows that esomeprazole controls pro-inflammatory and profibrotic molecules through nuclear translocation of the transcription factor nuclear factor-like 2 (Nrf2) and induction of the cytoprotective molecule heme oxygenase 1 (HO1). Genetic deletion of Nrf2 or pharmacological inhibition of HO1 impaired esomeprazole-mediated regulation of proinflammatory and profibrotic molecules. Additional studies indicate that activation of Mitogen Activated Protein Kinase (MAPK) pathway is involved in the process. Our experimental data was corroborated by bioinformatics studies of an NIH chemical library which hosts gene expression profiles of IPF lung fibroblasts treated with over 20,000 compounds including esomeprazole. Intriguingly, we found 45 genes that are upregulated in IPF but downregulated by esomeprazole. Pathway analysis showed that these genes are enriched for profibrotic processes. Unbiased high throughput RNA-seq study supported antifibrotic effect of esomeprazole and revealed several novel targets. Conclusions: Taken together, PPIs may play antifibrotic role in IPF through direct regulation of the MAPK/Nrf2/HO1 pathway to favorably influence the disease process in IPF. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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8. Poultry disease occurrences and their impacts in Ethiopia.
- Author
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Asfaw, Yohannes T., Ameni, Gobena, Medhin, Girmay, Gumi, Balako, Hagos, Yohannes, and Wieland, Barbara
- Abstract
Poultry production contributes significantly to the livelihoods of Ethiopian farmers and to the national economy although it is hampered by different factors, including poultry diseases. There is scarcity of published evidences on the occurrence and impacts of poultry diseases although such evidences are important for policy makers in designing appropriate interventions. A total of 595 households were interviewed and 11 FGDs were conducted to collect data on the occurrence of diseases and the number of dead chickens in the last 12 months. Hence, respiratory diseases, sudden death, and eye-face-head diseases were mentioned in all of the FGDs as the most frequently occurring disease in the districts. Of households interviewed, 86.1% reported poultry disease occurrence in the last 12 months, and gastrointestinal, eye-face-head, and neurological diseases were identified to be the top three ranked diseases of chickens in the districts. Flocks with access to diagnostic services (Adj. OR = 4.16; P = 0.004) and/or access to animal health providers (Adj. OR = 10.50; P = 0.001) were more likely to report disease occurrence. In the studied population, the diseases resulted in deaths of 2219 chickens valued at 352,219.5 Birr (11,740.65 USD) and a mean crude mortality of 31.87%. Female-lead households (mean difference = 5.95%; P = 0.018) and multiple age units present on the farm (mean difference = 20.92%; P = < 0.000) had higher chicken mortality. Similarly, higher mortality was reported in flocks without access to diagnosis (mean difference = 9.97%; P = < 0.000) and vaccination (mean difference = 12.34%; P = < 0.000) services. The high occurrence of disease and mortalities might be explained by a lack of an organized poultry health service delivery system in the country. Therefore, a carefully designed health service delivery system addressing needs of poultry producers, supported by relevant policy and corresponding strategies, is recommended to address the indicated challenges. Moreover, private health providers with well-defined roles need to be engaged to successfully and sustainably solve the poultry disease problems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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9. Topical Esomeprazole Mitigates Radiation-Induced Dermal Inflammation and Fibrosis.
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Pham, Ngoc, Ludwig, Michelle S., Wang, Min, Ebrahimpour, Afshin, Bonnen, Mark D., Diwan, Abdul Hafeez, Kim, Soo Jung, Bryan, Jason, Newton, Jared M., Sikora, Andrew G., Donovan, Donald T., Sandulache, Vlad, and Ghebre, Yohannes T.
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ESOMEPRAZOLE ,FIBROSIS ,HEME oxygenase ,SKIN inflammation ,INFLAMMATION ,MYOFIBROBLASTS - Abstract
Radiation therapy is a mainstream strategy in the treatment of several cancer types that are surgically unresectable. Unfortunately, cancer patients often suffer from unintended consequences of radiotherapy, including the development of skin inflammation (dermatitis), which may progress to fibrosis. These morbid complications often require interruption of radiotherapy and threaten the relapse of underlying cancer. Current treatment options for radiation dermatitis are suboptimal and compel the need to develop safer, more effective therapies. In this study, we assessed the biophysical properties of topically-formulated esomeprazole (here referred to as dermaprazole) and performed proof-of-concept studies to evaluate its efficacy in vitro and in vivo. We found that dermaprazole induced nuclear translocation of erythroid 2-related factor 2 (Nrf2) and significantly upregulated heme oxygenase 1 (HO1) gene and protein expression in a 3D human skin model. Our animal study demonstrated that dermaprazole improved macroscopic appearance of the irradiated skin and accelerated healing of the wounds. Histopathology data corroborated the photographic evidence and confirmed that both prophylactically and therapeutically administered dermaprazole conferred potent anti-inflammatory and antifibrotic effects. Gene expression data showed that dermaprazole downregulated several pro-oxidant, pro-inflammatory and profibrotic genes. In conclusion, topical formulation of the FDA-approved drug esomeprazole is highly effective in attenuating dermal inflammation and fibrosis. [ABSTRACT FROM AUTHOR]
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- 2019
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10. Radiation-Induced Lung Injury: Assessment and Management.
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Hanania, Alexander N., Mainwaring, Walker, Ghebre, Yohannes T., Hanania, Nicola A., and Ludwig, Michelle
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LUNG injuries ,THERAPEUTICS ,ETIOLOGY of diseases ,LUNG diseases ,PULMONARY fibrosis ,RADIATION injuries ,RADIOTHERAPY complications - Abstract
Radiation-induced lung injury (RILI) encompasses any lung toxicity induced by radiation therapy (RT) and manifests acutely as radiation pneumonitis and chronically as radiation pulmonary fibrosis. Because most patients with thoracic and breast malignancies are expected to undergo RT in their lifetime, many with curative intent, the population at risk is significant. Furthermore, indications for thoracic RT are expanding given the advent of stereotactic body radiation therapy (SBRT) or stereotactic ablative radiotherapy (SABR) for early-stage lung cancer in nonsurgical candidates as well as oligometastatic pulmonary disease from any solid tumor. Fortunately, the incidence of serious pulmonary complications from RT has decreased secondary to advances in radiation delivery techniques. Understanding the temporal relationship between RT and injury as well as the patient, disease, and radiation factors that help distinguish RILI from other etiologies is necessary to prevent misdiagnosis. Although treatment of acute pneumonitis is dependent on clinical severity and typically responds completely to corticosteroids, accurately diagnosing and identifying patients who may progress to fibrosis is challenging. Current research advances include high-precision radiation techniques, an improved understanding of the molecular basis of RILI, the development of small and large animal models, and the identification of candidate drugs for prevention and treatment. [ABSTRACT FROM AUTHOR]
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- 2019
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11. Valuing of Soil Capability in Land Surface Modeling.
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Morgan, Cristine L. S., Yimam, Yohannes T., Barlage, Michael, Gochis, David, and Dornblaser, Bright
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- 2017
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12. Proton Pump Inhibitors and Osteoporosis: Is Collagen a Direct Target?
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Ghebre, Yohannes T.
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PROTON pump inhibitors ,COLLAGEN ,OSTEOPOROSIS - Published
- 2020
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13. Anticancer therapy and lung injury: molecular mechanisms.
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Li, Li, Mok, Henry, Jhaveri, Pavan, Bonnen, Mark D, Sikora, Andrew G, Eissa, N. Tony, Komaki, Ritsuko U, and Ghebre, Yohannes T
- Abstract
Introduction: Chemotherapy and radiation therapy are two mainstream strategies applied in the treatment of cancer that is not operable. Patients with hematological or solid tumor malignancies substantially benefit from chemotherapeutic drugs and/or ionizing radiation delivered to the site of malignancy. However, considerable adverse effects, including lung inflammation and fibrosis, are associated with the use of these treatment modalities. Areas covered: As we move toward the era of precision health, we are compelled to understand the molecular basis of chemoradiation-induced pathological lung remodeling and to develop effective treatment strategies that mitigate the development of chronic lung disease (i.e. fibrosis) in cancer patients. The review discusses chemotherapeutic agents that are reported to induce or associate with acute and/or chronic lung injury. Expert commentary: There is a need to molecularly understand how chemotherapeutic drugs induce or associate with respiratory toxicities and whether such characteristics are inherently related to their antitumor effect or are collateral. Once such mechanisms have been identified and/or fully characterized, they may be able to guide disease-management decisions including effective intervention strategies for the adverse effects. In the meantime, radiation oncologists should be judicious on the dose of radiation delivered to the lungs, the volume of lung irradiated, and concurrent use of chemotherapeutic drugs. [ABSTRACT FROM AUTHOR]- Published
- 2018
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14. Silent Neoplastic Cardiac Invasion in Small Cell Lung Cancer: A Case Report and Review of the Literature.
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Pham, Ngoc, Bonnen, Mark D., and Ghebre, Yohannes T.
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SMALL cell lung cancer ,NON-small-cell lung carcinoma ,LITERATURE reviews ,PATHOLOGY ,CANCER invasiveness - Abstract
Objective: Rare co-existance of disease or pathology. Background: Secondary malignant tumor of the heart is one of the most life-threatening complications of lung cancer. Several published case reports have documented non-small cell lung cancer (NSCLC) patients with neoplastic cardiac invasion. However, the number of reported cases of small cell lung cancer (SCLC) with neoplastic cardiac invasion is limited. Case Report: We present a rare case of advanced SCLC in a patient with asymptomatic neoplastic cardiac invasion. We also discuss radiation therapy modalities that should be considered in SCLC patients with cardiac invasion. Conclusions: Clinicians should be vigilant about cases of SCLC with asymptomatic intra-cardiac invasion and practice caution when diagnosing, as well as treating with radiation as a monotherapy. [ABSTRACT FROM AUTHOR]
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- 2018
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15. Proton Pump Inhibitors in IPF: A Call for Clinical Trials.
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Ghebre, Yohannes T.
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PROTON pump inhibitors ,IDIOPATHIC pulmonary fibrosis ,THERAPEUTICS - Abstract
The recent FDA approval of two drugs, pirfenidone and nintedanib, for the treatment of idiopathic pulmonary fibrosis (IPF) has fueled interest in the development of additional drugs to treat the disease or its major clinical complications including cough and acute exacerbations. Since 2015, there are at least a dozen active interventional studies that are testing the efficacy of novel pharmacotherapies, exercise or stem cells in modifying the disease process in IPF. Additionally, there are combinatorial studies evaluating the effectiveness of pirfenidone or nintedanib in combination with other agents. However, there remains an urgent need for clinical trials to prospectively evaluate the efficacy of existing drugs with promising retrospective data, such as proton pump inhibitors (PPIs), in IPF. Several retrospective cohorts have provided tantalizing data supporting the beneficial effect of PPIs in patients with well-defined IPF. This review provides the general outlook of pharmacotherapies in IPF, and highlights preclinical and retrospective clinical data to make a case for randomized controlled clinical trials of PPIs in IPF. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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16. Therapeutic Efficacy of Esomeprazole in Cotton Smoke-Induced Lung Injury Model.
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Nelson, Christina, Lee, Jameisha, Kang Ko, Sikora, Andrew G., Bonnen, Mark D., Enkhbaatar, Perenlei, Ghebre, Yohannes T., Hongwei Yao, and Shetty, Sreerama
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ESOMEPRAZOLE ,LUNG injury treatment ,ANTACIDS ,THERAPEUTICS - Abstract
Proton pump inhibitors (PPIs) are well-known antacid drugs developed to treat gastric disorders. Emerging studies demonstrate that PPIs possess biological activities that extend beyond inhibition of H+/K+ ATPase (proton pumps) expressed in parietal cells of the stomach. Some of the extra-gastric activities of PPIs include modulation of epithelial, endothelial, and immune cell functions. Recently, we reported that PPIs suppress the expression of several proinflammatory and profibrotic molecules, as well as enhance antioxidant mechanisms in order to favorably regulate lung inflammation and fibrosis in an animal model of bleomycin-induced lung injury. In addition, several retrospective clinical studies report that the use of PPIs is associated with beneficial outcomes in chronic lung diseases including idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD). Based on these preclinical and clinical observations, we hypothesized that PPIs ameliorate smoke-induced lung injury. Accordingly, we evaluated the pharmacological efficacy of the PPI esomeprazole in a mouse model of cotton smoke-induced lung injury. The animals were exposed to cotton smoke for 3-weeks in the presence or absence of esomeprazole treatment. We found that therapeutic administration of esomeprazole significantly inhibited the progression of fibrosis throughout the lungs of the animals in this group compared to controls. In addition, esomeprazole also reduced circulating markers of inflammation and fibrosis. Overall, our work extends the emerging anti-inflammatory and antifibrotic potential of PPIs and their role in modulation of chronic lung diseases. [ABSTRACT FROM AUTHOR]
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- 2017
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17. Idiopathic Pulmonary Fibrosis: Novel Concepts of Proton Pump Inhibitors as Antifibrotic Drugs.
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Ghebre, Yohannes T. and Raghu, Ganesh
- Abstract
The prevalence of abnormal acid gastroesophageal reflux (GER) is higher in patients with idiopathic pulmonary fibrosis (IPF) than in matched control subjects. Several studies demonstrated that more than one-third of patients with IPF have abnormal esophageal acid exposures. In addition, many of these studies indicate that the majority of patients with IPF have silent reflux with no symptoms of GER. Findings of abnormal reflux persist in a large proportion of patients with IPF placed on antacid therapy such as proton pump inhibitors (PPIs). This seemingly paradoxical observation suggests that either patients with IPF are somehow resistant to PPI-based intervention or PPIs are inherently unable to suppress acid GER. By contrast, patients with IPF who undergo Nissen fundoplication surgery are effectively relieved from the complications of GER, and retrospective studies suggest improved lung function. Retrospective, anecdotal data suggest a beneficial role of PPIs in IPF including stabilization of lung function, reduction in episodes of acute exacerbation, and enhanced longevity. The recent evidence-based guidelines for treatment of IPF approved conditional recommendation of PPIs for all patients with IPF regardless of their GER status. Recently, we have reported that PPIs possess antiinflammatory and antifibrotic activities by directly suppressing proinflammatory cytokines, profibrotic proteins, and proliferation of lung fibroblasts. Our study provides an alternative explanation for the beneficial effect of PPIs in IPF. In this Perspective, we reviewed emerging progress on antifibrotic effect of PPIs using IPF as a disease model. In addition, we summarized surgical and pharmacological interventions for GER and their downstream effect on lung physiology. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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18. Proton Pump Inhibitors Accelerate Endothelial Senescence.
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Yepuri, Gautham, Sukhovershin, Roman, Nazari-Shafti, Timo Z., Petrascheck, Michael, Ghebre, Yohannes T., and Cooke, John P.
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- 2016
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19. Optimal ROS Signaling Is Critical for Nuclear Reprogramming.
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Zhou, Gang, Meng, Shu, Li, Yanhui, Ghebre, Yohannes T., and Cooke, John P.
- Abstract
Summary Efficient nuclear reprogramming of somatic cells to pluripotency requires activation of innate immunity. Because innate immune activation triggers reactive oxygen species (ROS) signaling, we sought to determine whether there was a role of ROS signaling in nuclear reprogramming. We examined ROS production during the reprogramming of doxycycline (dox)-inducible mouse embryonic fibroblasts (MEFs) carrying the Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc [OSKM]) into induced pluripotent stem cells (iPSCs). ROS generation was substantially increased with the onset of reprogramming. Depletion of ROS via antioxidants or Nox inhibitors substantially decreased reprogramming efficiency. Similarly, both knockdown and knockout of p22 phox —a critical subunit of the Nox (1–4) complex—decreased reprogramming efficiency. However, excessive ROS generation using genetic and pharmacological approaches also impaired reprogramming. Overall, our data indicate that ROS signaling is activated early with nuclear reprogramming, and optimal levels of ROS signaling are essential to induce pluripotency. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
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20. Modulating DDAH/NOS Pathway to Discover Vasoprotective Insulin Sensitizers.
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Lai, Li and Ghebremariam, Yohannes T.
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INSULIN resistance ,NITRIC-oxide synthases ,ARGININE ,HYDROLASES ,CARDIOVASCULAR diseases risk factors ,METABOLIC disorders - Abstract
Insulin resistance syndrome (IRS) is a configuration of cardiovascular risk factors involved in the development of metabolic disorders including type 2 diabetes mellitus. In addition to diet, age, socioeconomic, and environmental factors, genetic factors that impair insulin signaling are centrally involved in the development and exacerbation of IRS. Genetic and pharmacological studies have demonstrated that the nitric oxide (NO) synthase (NOS) genes are critically involved in the regulation of insulin-mediated glucose disposal. The generation of NO by the NOS enzymes is known to contribute to vascular homeostasis including insulin-mediated skeletal muscle vasodilation and insulin sensitivity. By contrast, excessive inhibition of NOS enzymes by exogenous or endogenous factors is associated with insulin resistance (IR). Asymmetric dimethylarginine (ADMA) is an endogenous molecule that competitively inhibits all the NOS enzymes and contributes to metabolic perturbations including IR. The concentration of ADMA in plasma and tissue is enzymatically regulated by dimethylarginine dimethylaminohydrolase (DDAH), a widely expressed enzyme in the cardiovascular system. In preclinical studies, overexpression of DDAH has been shown to reduce ADMA levels, improve vascular compliance, and increase insulin sensitivity. This review discusses the feasibility of the NOS/DDAH pathway as a novel target to develop vasoprotective insulin sensitizers. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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21. ENDOTHELIUM-DERIVED NITRIC OXIDE AS AN ANTIATHEROGENIC MECHANISM: IMPLICATIONS FOR THERAPY.
- Author
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Sukhovershin, Roman A., Yepuri, Gautham, and Ghebremariam, Yohannes T.
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ENDOTHELIUM ,NITRIC oxide ,HOMEOSTASIS ,BIOAVAILABILITY ,VASODILATORS - Abstract
Endothelium-derived nitric oxide (eNO) is a multifunctional signaling molecule critically involved in the maintenance of metabolic and cardiovascular homeostasis. In addition to its role as a potent endogenous vasodilator, eNO suppresses key processes in vascular lesion formation and opposes atherogenesis. This review discusses eNO as an antiatherogenic molecule and highlights factors that influence its bioavailability and therapeutic approaches to restore or enhance its levels [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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22. Proton pump inhibitors and vascular function: A prospective cross-over pilot study.
- Author
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Ghebremariam, Yohannes T., Cooke, John P., Khan, Fouzia, Thakker, Rahul N., Chang, Peter, Shah, Nigam H., Nead, Kevin T., and Leeper, Nicholas J.
- Subjects
PROTON pump inhibitors ,ENZYME inhibitors ,GASTRIC diseases ,CARDIOVASCULAR diseases risk factors ,ETIOLOGY of diseases ,THERAPEUTICS - Abstract
Proton pump inhibitors (PPIs) are commonly used drugs for the treatment of gastric reflux. Recent retrospective cohorts and large database studies have raised concern that the use of PPIs is associated with increased cardiovascular (CV) risk. However, there is no prospective clinical study evaluating whether the use of PPIs directly causes CV harm. We conducted a controlled, open-label, cross-over pilot study among 21 adults aged 18 and older who are healthy (n=11) or have established clinical cardiovascular disease (n=10). Study subjects were assigned to receive a PPI (Prevacid; 30 mg) or a placebo pill once daily for 4 weeks. After a 2-week washout period, participants were crossed over to receive the alternate treatment for the ensuing 4 weeks. Subjects underwent evaluation of vascular function (by the EndoPAT technique) and had plasma levels of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of endothelial function previously implicated in PPI-mediated risk) measured prior to and after each treatment interval. We observed a marginal inverse correlation between the EndoPAT score and plasma levels of ADMA (r = −0.364). Subjects experienced a greater worsening in plasma ADMA levels while on PPI than on placebo, and this trend was more pronounced amongst those subjects with a history of vascular disease. However, these trends did not reach statistical significance, and PPI use was also not associated with an impairment in flow-mediated vasodilation during the course of this study. In conclusion, in this open-label, cross-over pilot study conducted among healthy subjects and coronary disease patients, PPI use did not significantly influence vascular endothelial function. Larger, long-term and blinded trials are needed to mechanistically explain the correlation between PPI use and adverse clinical outcomes, which has recently been reported in retrospective cohort studies. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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23. Pleiotropic effect of the proton pump inhibitor esomeprazole leading to suppression of lung inflammation and fibrosis.
- Author
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Ghebremariam, Yohannes T., Cooke, John P., Gerhart, William, Griego, Carol, Brower, Jeremy B., Doyle-Eisele, Melanie, Moeller, Benjamin C., Qingtao Zhou, Ho, Lawrence, de Andrade, Joao, Raghu, Ganesh, Peterson, Leif, Rivera, Andreana, and Rosen, Glenn D.
- Subjects
ESOMEPRAZOLE ,IMMUNOSUPPRESSION ,PULMONARY fibrosis ,PNEUMONIA ,PROTON pump inhibitors ,MULTIDRUG resistance ,THERAPEUTICS - Abstract
Background: The beneficial outcome associated with the use of proton pump inhibitors (PPIs) in idiopathic pulmonary fibrosis (IPF) has been reported in retrospective studies. To date, no prospective study has been conducted to confirm these outcomes. In addition, the potential mechanism by which PPIs improve measures of lung function and/ or transplant-free survival in IPF has not been elucidated. Methods: Here, we used biochemical, cell biological and preclinical studies to evaluate regulation of markers associated with inflammation and fibrosis. In our in vitro studies, we exposed primary lung fibroblasts, epithelial and endothelial cells to ionizing radiation or bleomycin; stimuli typically used to induce inflammation and fibrosis. In addition, we cultured lung fibroblasts from IPF patients and studied the effect of esomeprazole on collagen release. Our preclinical study tested efficacy of esomeprazole in a rat model of bleomycin-induced lung injury. Furthermore, we performed retrospective analysis of interstitial lung disease (ILD) databases to examine the effect of PPIs on transplant- free survival. Results: The cell culture studies revealed that esomeprazole controls inflammation by suppressing the expression of pro-inflammatory molecules including vascular cell adhesion molecule-1, inducible nitric oxide synthase, tumor necrosis factor-alpha (TNF-α) and interleukins (IL-1β and IL-6). The antioxidant effect is associated with strong induction of the stress-inducible cytoprotective protein heme oxygenase-1 (HO1) and the antifibrotic effect is associated with potent inhibition of fibroblast proliferation as well as downregulation of profibrotic proteins including receptors for transforming growth factor β (TGFβ), fibronectin and matrix metalloproteinases (MMPs). Furthermore, esomeprazole showed robust effect in mitigating the inflammatory and fibrotic responses in a murine model of acute lung injury. Finally, retrospective analysis of two ILD databases was performed to assess the effect of PPIs on transplant-free survival in IPF patients. Intriguingly, this data demonstrated that IPF patients on PPIs had prolonged survival over controls (median survival of 3.4 vs 2 years). Conclusions: Overall, these data indicate the possibility that PPIs may have protective function in IPF by directly modulating the disease process and suggest that they may have other clinical utility in the treatment of extra-intestinal diseases characterized by inflammatory and/or fibrotic phases. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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24. Proton Pump Inhibitor Usage and the Risk of Myocardial Infarction in the General Population.
- Author
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Shah, Nigam H., LePendu, Paea, Bauer-Mehren, Anna, Ghebremariam, Yohannes T., Iyer, Srinivasan V., Marcus, Jake, Nead, Kevin T., Cooke, John P., and Leeper, Nicholas J.
- Subjects
PROTON pump inhibitors ,MYOCARDIAL infarction risk factors ,HEALTH outcome assessment ,CLOPIDOGREL ,ACUTE coronary syndrome ,GASTROESOPHAGEAL reflux ,PATIENTS ,DISEASES - Abstract
Background and Aims: Proton pump inhibitors (PPIs) have been associated with adverse clinical outcomes amongst clopidogrel users after an acute coronary syndrome. Recent pre-clinical results suggest that this risk might extend to subjects without any prior history of cardiovascular disease. We explore this potential risk in the general population via data-mining approaches. Methods: Using a novel approach for mining clinical data for pharmacovigilance, we queried over 16 million clinical documents on 2.9 million individuals to examine whether PPI usage was associated with cardiovascular risk in the general population. Results: In multiple data sources, we found gastroesophageal reflux disease (GERD) patients exposed to PPIs to have a 1.16 fold increased association (95% CI 1.09–1.24) with myocardial infarction (MI). Survival analysis in a prospective cohort found a two-fold (HR = 2.00; 95% CI 1.07–3.78; P = 0.031) increase in association with cardiovascular mortality. We found that this association exists regardless of clopidogrel use. We also found that H
2 blockers, an alternate treatment for GERD, were not associated with increased cardiovascular risk; had they been in place, such pharmacovigilance algorithms could have flagged this risk as early as the year 2000. Conclusions: Consistent with our pre-clinical findings that PPIs may adversely impact vascular function, our data-mining study supports the association of PPI exposure with risk for MI in the general population. These data provide an example of how a combination of experimental studies and data-mining approaches can be applied to prioritize drug safety signals for further investigation. [ABSTRACT FROM AUTHOR]- Published
- 2015
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- View/download PDF
25. IODINE DEFICIENCY DISORDERS (IDD) IN BURIE AND WOMBERMA DISTRICTS, WEST GOJJAM, ETHIOPIA.
- Author
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Aweke, K. A., Adamu, B. T., Girmay, A. M., Yohannes, T., Alemnesh, Z., and Abuye, C.
- Subjects
IODINE deficiency diseases ,BIOAVAILABILITY ,PUBLIC health ,ENDEMIC goiter ,DEVELOPING countries - Abstract
Iodine deficiency disorders (IDD) affect millions of people in developing countries mainly due to dietary iodine deficiency and aggravating factors that affect the bioavailability of iodine in the body. Iodine deficiency disorder is one of the public health problems of Ethiopia. Recent findings show that both endemic and nonendemic areas have high goiter rates. Burie and Womberma districts are two of the endemic goiter areas in the country. The etiology of goiter in these areas is not fully studied so far. The objective of this cross-sectional community based study was to assess the magnitude and causes of goiter. The study was conducted in July 2010. The sample size was determined by assuming 50% prevalence of total goiter rate, 5% error, 95% confidence interval, design effect of 1(random) and 5% of non-response rate. A two-stagerandom sampling (sub-district and village) was used to select children aged 6-12 years and their biological mothers from10 randomly selected villages in each of the districts. Overall, 403 households participated in the study. The assessment was conducted using palpation of thyroid size, urinary iodine level determination, household level interview and Focus Group Discussion (FGD). The study revealed a total goiter prevalence rate of 54% and 30.1% in children and their biological mothers, respectively. More than 64% of the children were severely iodine deficient. The major cause for goiter as revealed by urinary iodine level and concentration of iodized salt is dietary iodine deficiency. There are no goitrogenic foods such as cassava; however, goitrogenic chemicals such as Dichlorodiphenyltrichloroethane (DDT) and 2,4-Dichlorophenoxyacetic acid (2,4-D) were widely used. The study areas are known for surplus produce of cereals, legumes and chilli. In order to reverse the problem, immediate and sustainable distribution of iodated salt/oil capsule, prohibition of direct application of pesticides on foods and awareness creation on adverse effects of IDD and benefits of iodine nutrition is highly recommended. [ABSTRACT FROM AUTHOR]
- Published
- 2014
26. Characterization of a Fluorescent Probe for Imaging Nitric Oxide.
- Author
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Ghebremariam, Yohannes T., Huang, Ngan F., Kambhampati, Swetha, Volz, Katharina S., Joshi, Gururaj G., anslyn, Eric V., and Cooke, John P.
- Subjects
VASCULAR endothelial cells ,FLUORESCENT probes ,MEDICAL imaging systems ,ASYMMETRIC dimethylarginine ,NITRIC-oxide synthases ,CELLULAR signal transduction - Abstract
Background: Nitric oxide (NO), a potent vasodilator and anti-atherogenic molecule, is synthesized in various cell types, including vascular endothelial cells (ECs). The biological importance of NO enforces the need to develop and characterize specific and sensitive probes. To date, several fluorophores, chromophores and colorimetric techniques have been developed to detect NO or its metabolites (NO
2 and NO3 ) in biological fluids, viable cells or cell lysates. Methods: Recently, a novel probe (NO550 ) has been developed and reported to detect NO in solutions and in primary astrocytes and neuronal cells with a fluorescence signal arising from a nonfluorescent background. Results: Here, we report further characterization of this probe by optimizing conditions for the detection and imaging of NO products in primary vascular ECs, fibroblasts, and embryonic stem cell- and induced pluripotent stem cell-derived ECs in the absence and presence of pharmacological agents that modulate NO levels. In addition, we studied the stability of this probe in cells over time and evaluated its compartmentalization in reference to organelle-labeling dyes. Finally, we synthesized an inherently fluorescent diazo ring compound (AZO550 ) that is expected to form when the nonfluorescent NO550 reacts with cellular NO, and compared its cellular distribution with that of NO550 . Conclusion: NO550 is a promising agent for imaging NO at baseline and in response to pharmacological agents that modulate its levels. © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]- Published
- 2014
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- View/download PDF
27. Unexpected effect of proton pump inhibitors: elevation of the cardiovascular risk factor asymmetric dimethylarginine.
- Author
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Ghebremariam, Yohannes T, Lependu, Paea, Lee, Jerry C, Erlanson, Daniel A, Slaviero, Anna, Shah, Nigam H, Leiper, James, and Cooke, John P
- Published
- 2013
- Full Text
- View/download PDF
28. Unexpected Effect of Proton Pump Inhibitors.
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Ghebremariam, Yohannes T., LePendu, Paea, Lee, Jerry C., Erlanson, Daniel A., Slaviero, Anna, Shah, Nigam H., Leiper, James, and Cooke, John P.
- Published
- 2013
- Full Text
- View/download PDF
29. FXR Agonist INT-747 Upregulates DDAH Expression and Enhances Insulin Sensitivity in High-Salt Fed Dahl Rats.
- Author
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Ghebremariam, Yohannes T., Yamada, Keisuke, Lee, Jerry C., Johnson, Christine L. C., Atzler, Dorothee, Anderssohn, Maike, Agrawal, Rani, Higgins, John P., Patterson, Andrew J., Böger, Rainer H., and Cooke, John P
- Subjects
GENE expression ,INSULIN resistance ,LABORATORY rats ,SALT in animal nutrition ,GENETICS ,HYPERTENSION ,CARDIOVASCULAR pharmacology ,ENDOCRINOLOGY - Abstract
Aims: Genetic and pharmacological studies have shown that impairment of the nitric oxide (NO) synthase (NOS) pathway is associated with hypertension and insulin-resistance (IR). In addition, inhibition of NOS by the endogenous inhibitor, asymmetric dimethylarginine (ADMA), may also result in hypertension and IR. On the other hand, overexpression of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that metabolizes ADMA, in mice is associated with lower ADMA, increased NO and enhanced insulin sensitivity. Since DDAH carries a farnesoid X receptor (FXR)-responsive element, we aimed to upregulate its expression by an FXR-agonist, INT-747, and evaluate its effect on blood pressure and insulin sensitivity. Methods and Results: In this study, we evaluated the in vivo effect of INT-747 on tissue DDAH expression and insulin sensitivity in the Dahl rat model of salt-sensitive hypertension and IR (Dahl-SS). Our data indicates that high salt (HS) diet significantly increased systemic blood pressure. In addition, HS diet downregulated tissue DDAH expression while INT-747 protected the loss in DDAH expression and enhanced insulin sensitivity compared to vehicle controls. Conclusion: Our study may provide the basis for a new therapeutic approach for IR by modulating DDAH expression and/or activity using small molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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- View/download PDF
30. Limited Gene Expression Variation in Human Embryonic Stem Cell and Induced Pluripotent Stem Cell-Derived Endothelial Cells.
- Author
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White, Mark P., Rufaihah, Abdul J., Liu, Lei, Ghebremariam, Yohannes T., Ivey, Kathryn N., Cooke, John P., and Srivastava, Deepak
- Subjects
TRANSCRIPTION factors ,GENE expression ,EMBRYONIC stem cells ,PLURIPOTENT stem cells ,ENDOTHELIAL cells ,CELL differentiation ,BIOMARKERS - Abstract
Recent evidence suggests human embryonic stem cell (hESC) and induced pluripotent stem (iPS) cell lines have differences in their epigenetic marks and transcriptomes, yet the impact of these differences on subsequent terminally differentiated cells is less well understood. Comparison of purified, homogeneous populations of somatic cells derived from multiple independent human iPS and ES lines will be required to address this critical question. Here, we report a differentiation protocol based on embryonic development that consistently yields large numbers of endothelial cells (ECs) derived from multiple hESCs or iPS cells. Mesoderm differentiation of embryoid bodies was maximized, and defined growth factors were used to generate KDR
+ EC progenitors. Magnetic purification of a KDR+ progenitor subpopulation resulted in an expanding, homogeneous pool of ECs that expressed EC markers and had functional properties of ECs. Comparison of the transcriptomes revealed limited gene expression variability between multiple lines of human iPS-derived ECs or between lines of ES- and iPS-derived ECs. These results demonstrate a method to generate large numbers of pure human EC progenitors and differentiated ECs from pluripotent stem cells and suggest individual lineages derived from human iPS cells may have significantly less variance than their pluripotent founders. S TEM C ells 2013;31:92-103 [ABSTRACT FROM AUTHOR]- Published
- 2013
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31. Development of a Dimethylarginine Dimethylaminohydrolase (DDAH) Assay for High-Throughput Chemical Screening.
- Author
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Ghebremariam, Yohannes T., Erlanson, Daniel A., Yamada, Keisuke, and Cooke, John P.
- Subjects
NITRIC oxide ,NITROGEN compounds ,DIABETES ,HYPERTENSION ,BLOOD circulation disorders ,PULMONARY fibrosis - Abstract
Nitric oxide (NO) is a potent signaling molecule that needs to be tightly regulated to maintain metabolic and cardiovascular homeostasis. The nitric oxide synthase (NOS)/dimethylarginine dimethylaminohydrolase (DDAH)/asymmetric dimethylarginine (ADMA) pathway is central to this regulation. Specifically, the small-molecule ADMA competitively inhibits NOS, thus lowering NO levels. The majority of ADMA is physiologically metabolized by DDAH, thus maintaining NO levels at a physiological concentration. However, under pathophysiological conditions, DDAH activity is impaired, in part as a result of its sensitivity to oxidative stress. Therefore, the application of high-throughput chemical screening for the discovery of small molecules that could restore or enhance DDAH activity might have significant potential in treating metabolic and vascular diseases characterized by reduced NO levels, including atherosclerosis, hypertension, and insulin resistance. By contrast, excessive generation of NO (primarily driven by inducible NOS) could play a role in idiopathic pulmonary fibrosis, sepsis, migraine headaches, and some types of cancer. In these conditions, small molecules that inhibit DDAH activity might be therapeutically useful. Here, we describe optimization and validation of a highly reproducible and robust assay successfully used in a high-throughput screen for DDAH modulators. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
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- View/download PDF
32. Cost implications of delays to tuberculosis diagnosis among pulmonary tuberculosis patients in Ethiopia.
- Author
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Mesfin, Mengiste M., Newell, James N., Madeley, Richard J., Mirzoev, Tolib N., Tareke, Israel G., Kifle, Yohannes T., Gessessew, Amanuel, and Walley, John D.
- Subjects
TUBERCULOSIS diagnosis ,COST effectiveness ,LUNG diseases ,PUBLIC health - Abstract
Background: Delays seeking care worsen the burden of tuberculosis and cost of care for patients, families and the public health system. This study investigates costs of tuberculosis diagnosis incurred by patients, escorts and the public health system in 10 districts of Ethiopia.Methods: New pulmonary tuberculosis patients > or = 15 years old were interviewed regarding their health care seeking behaviour at the time of diagnosis. Using a structured questionnaire patients were interviewed about the duration of delay at alternative care providers and the public health system prior to diagnosis. Costs incurred by patients, escorts and the public health system were quantified through patient interview and review of medical records.Results: Interviews were held with 537 (58%) smear positive patients and 387 (42%) smear negative pulmonary patients. Of these, 413 (45%) were female; 451 (49%) were rural residents; and the median age was 34 years. The mean (median) days elapsed for consultation at alternative care providers and public health facilities prior to tuberculosis diagnosis was 5 days (0 days) and 3 (3 days) respectively. The total median cost incurred from first consultation to diagnosis was $27 per patient (mean = $59). The median costs per patient incurred by patient, escort and the public health system were $16 (mean = $29), $3 (mean = $23) and $3 (mean = $7) respectively. The total cost per patient diagnosed was higher for women, rural residents; those who received government food for work support, patients with smear negative pulmonary tuberculosis and patients who were not screened for TB in at least one district diagnostic centers.Conclusions: The costs of tuberculosis diagnosis incurred by patients and escorts represent a significant portion of their monthly income. The costs arising from time lost in seeking care comprised a major portion of the total cost of diagnosis, and may worsen the economic position of patients and their families. Getting treatment from alternative sources and low index of suspicion public health providers were key problems contributing to increased cost of tuberculosis diagnosis. Thus, the institution of effective systems of referral, ensuring screening of suspects across the district public health system and the involvement of alternative care providers in district tuberculosis control can reduce delays and the financial burden to patients and escorts. [ABSTRACT FROM AUTHOR]- Published
- 2010
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- View/download PDF
33. Cell-free production of transducible transcription factors for nuclear reprogramming.
- Author
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Yang, William C., Patel, Kedar G., Lee, Jieun, Ghebremariam, Yohannes T., Wong, H. Edward, Cooke, John P., and Swartz, James R.
- Published
- 2009
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34. Land Surface Parameterization at Exposed Playa and Desert Region to Support Dust Emissions Estimates in Southern California, United States.
- Author
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Cheng, Yen-Ben, Dickey, Hank, Yimam, Yohannes T., Schmid, Brian, Paxton, Bronwyn, Schreuder, Maarten, and Tran, Reed
- Subjects
DESERTS ,AIR quality ,REMOTE sensing ,SOIL moisture ,PARAMETERIZATION ,MINERAL dusts - Abstract
Remote sensing technologies provide a unique opportunity to identify ground surfaces that are more susceptible to dust emissions at a large scale. As part of the Salton Sea Air Quality Mitigation Program (SSAQMP) of the Imperial Irrigation District (IID), efforts have been made to improve our understanding of fugitive, wind-blown dust emissions around the Salton Sea region in Southern California, United States. Field campaigns were conducted for multiple years to evaluate surface conditions and measure the dust emissions potential in the area. Data collected during the field work were coupled with remote sensing imagery and data mining techniques to map surface characteristics that are important in identifying dust emissions potential. Around the playa domain, surface crust type, sand presence, and soil moisture were estimated. Geomorphic surface types were mapped in the desert domain. Overall accuracy ranged from 91.7% to 99.4% for the crust type mapping. Sand presence mapping showed consistent and slightly better accuracy, ranging from 96.2% to 99.7%. Soil moisture assessment agreed with precipitation records. Geomorphic mapping in the desert domain achieved accuracy above 93.5%, and the spatial pattern was consistent with previous studies. These land surface condition assessments provide important information to support dust emissions estimates in the region. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
35. Survey on Blockchain for Smart Grid Management, Control, and Operation.
- Author
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Aklilu, Yohannes T. and Ding, Jianguo
- Subjects
BLOCKCHAINS ,DECENTRALIZATION in management ,ENERGY consumption ,DATA management ,OPERATIONS management ,MACHINE-to-machine communications - Abstract
Power generation, distribution, transmission, and consumption face ongoing challenges such as smart grid management, control, and operation, resulting from high energy demand, the diversity of energy sources, and environmental or regulatory issues. This paper provides a comprehensive overview of blockchain-based solutions for smart grid management, control, and operations. We systematically summarize existing work on the use and implementation of blockchain technology in various smart grid domains. The paper compares related reviews and highlights the challenges in the management, control, and operation for a blockchain-based smart grid as well as future research directions in the five categories: collaboration among stakeholders; data analysis and data management; control of grid imbalances; decentralization of grid management and operations; and security and privacy. All these aspects have not been covered in previous reviews. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
36. COVID-19-induced Lung Fibrosis.
- Author
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Ghebre, Yohannes T.
- Subjects
COVID-19 testing ,PULMONARY fibrosis ,ANTIVIRAL agents ,COMPUTED tomography ,VIRAL load - Abstract
Although effective vaccines, antiviral agents and respiratory therapy have reduced the burden of coronavirus disease 2019 (COVID-19) complications in patients, much remains to be studied about the fate of patients with long COVID-19 who have severe complications that have lasted several weeks to months as a result of SARS-CoV-2 infection. More specifically, it is not known if these patients have an increased risk of pathological lung remodelling. The purpose of this editorial is to discuss the emerging preclinical and clinical data regarding the risk of pulmonary fibrosis after SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]
- Published
- 2022
37. Structures of Mn(II) complexes of bis(2-pyridylmethyl)amine (bpa) and (2-pyridylmethyl)(6-methyl-2-pyridylmethyl)amine (Mebpa): geometric isomerism in the solid state.
- Author
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Gultneh, Yilma, Ahvazi†, Bijan, Tesema‡, Yohannes T., Yisgedu§, Teshome B., and Butcher, Ray J.
- Subjects
METAL complexes ,X-ray diffractometers ,ACETONITRILE ,CRYSTALLOGRAPHY ,ISOMERISM ,ORGANOMANGANESE compounds ,SOLID state chemistry - Abstract
The crystal structures of [Mn(bpa)2](ClO4)2 (1), [bpa = bis(2-pyridylmethyl)amine], and Mn(6-Mebpa)2(ClO4)2 (2), [6-Mebpa = (6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine] have been determined. In 1, two facial [Mn(bpa)2]2+ isomers are observed in the same unit cell, one with Ci (1a) and the other with C2 (1b) symmetries. In 2, only the isomer with C2 symmetry is observed. The structure of [Mn(bpa)2]2+ with only C2 symmetry has been reported previously (Inorg. Chem., 31, 4611 (1992)). The bond length order Mn–Namine > Mn–Npyridyl, observed in the C2 and the Ci isomers in the crystals of 1, is the reverse of the order observed in the structure of [Mn(bpa)2](ClO4)2 which contains only the C2 isomer in the unit cell. The structure of 2 in which only the C2 isomer is found, also shows the bond length order Mn–Npyridyl > Mn–Namine. In cyclic voltammetric experiments in acetonitrile solutions, 1 and 2 show irreversible anodic peaks at Ep = 1.60 and 1.90 V respectively, (vs. Ag/AgCl), assigned to the oxidation of Mn(II) to Mn(III). The substantially higher oxidation potential of 2 is attributable to a higher rearrangement energy in complex 2 due to the steric effect of the methyl substituent. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
38. Curcumin Inhibits the Classical and the Alternate Pathways of Complement Activation.
- Author
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KULKARNI, AMOD P., GHEBREMARIAM, YOHANNES T., and KOTWAL, GIRISH J.
- Subjects
TURMERIC ,QUERCETIN ,SODIUM hydroxide ,ZYMOSAN ,PROTEINS - Abstract
Curcumin (Cur), the golden yellow phenolic compound in turmeric, is well studied for its medicinal properties. In the current investigation, Cur dissolved using sodium hydroxide solution (CurNa) was tested for in vitro complement inhibitory activity and compared with rosmarinic acid (RA) and quercetin (Qur) dissolved using sodium hydroxide (RANa and QurNa, respectively) and the vaccinia virus complement control protein (VCP). The comparative study indicated that CurNa inhibited the classical complement pathway dose dependently (IC
50 = 404μM). CurNa was more active than RANa, but less active than QurNa. VCP was about 2,212, 2,786, and 4,520 times more active than QurNa, CurNa, and RANa, respectively. Further study revealed that Cur- Na dose dependently inhibited zymosan-induced activation of the alternate pathway of complement activation. [ABSTRACT FROM AUTHOR]- Published
- 2005
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- View/download PDF
39. Anti-HIV, Anti-Poxvirus, and Anti-SARS Activity of a Nontoxic, Acidic Plant Extract from the Trifollium Species Secomet-V/anti-Vac Suggests That It Contains a Novel Broad-Spectrum Antiviral.
- Author
-
KOTWAL, GIRISH J., KACZMAREK, JENNIFER N., LEIVERS, STEVEN, GHEBREMARIAM, YOHANNES T., KULKARNI, AMOD P., BAUER, GABRIELE, BEER, CORENA, PREISER, WOLFGANG, and MOHAMED, ABDU RAHMAN
- Subjects
PLANT extracts ,DRUG side effects ,HIV ,THERAPEUTICS ,ANTIVIRAL agents - Abstract
Enveloped animal viruses such as human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus, human papillomavirus, Marburg, and influenza are major public health concerns around the world. The prohibitive cost of antiretroviral (ARV) drugs for most HIV-infected patients in sub- Saharan Africa and the serious side effects in those who have access to ARV drugs make a compelling case for the study of complementary and alternative therapies. Such therapies should have scientifically proved antiviral activity and minimal toxic effects. A plant extract, Secomet-V, with an anecdotal indication in humans for promise as an anti-HIV treatment, was investigated. Using a previously described attenuated vaccinia virus vGK5, we established the antiviral activity of Secomet-V. Chemical analysis showed that it has an acidic pH, nontoxic traces of iron (<10 ppm), and almost undetectable levels of arsenic (<1.0 ppm). The color varies from colorless to pale yellow to dark brown. The active agent is heat stable at least up to sterilizing temperature of 121°C. The crude plant extract is a mixture of several small molecules separable by high-pressure liquid chromatography. The HIV viral loads were significantly reduced over several months in a few patients monitored after treatment with Secomet-V. Secomet-V was also found to have antiviral activity against the SARS virus but not against the West Nile virus. Secomet-V, therefore, is a broad-spectrum antiviral, which possibly works by neutralizing viral infectivity, resulting in the prevention of viral attachment. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
40. Intervention Strategies and Agents Mediating the Prevention of Xenorejection.
- Author
-
GHEBREMARIAM, YOHANNES T., SMITH, SCOTT A., ANDERSON, J B, KAHN, D, and KOTWAL, GIRISH J.
- Subjects
TRANSPLANTATION of organs, tissues, etc. ,PROTEINS ,VIRUS diseases in cattle ,TRANSGENIC organisms ,ENDOTHELIUM - Abstract
Xenotransplantation, the transplantation of cells, tissues, and/or organs across species, has proven to be an enormous challenge, resulting in only limited achievements over the last century. Unlike allotransplantation, the immunologic barriers involved in xenotransplant rejection are aggressive and usually occur within minutes in a hyperacute fashion. The use of organs from phylogenetically related concordant species may not be practical. Discordant xenotransplantation is characterized by hyperacute graft rejection, and to use nonprimate discordant organs for human benefit will require manipulation of the taxonomic differences. The hyperacute rejection process is primarily due to the attachment of preformed xenoreactive antibodies to the donor vascular endothelium, which results in hyperactivation of the complement system beyond the control of the natural complement regulatory proteins. Understanding the complex and diverse immune components involved in hyperacute, acute, and accelerated rejections has resulted in the development of different hematologic and molecular strategies. Plasmapheresis has been used to remove xenoantibodies, and xenoperfusion techniques are used to create a suitable and familiar environment for the xenograft. Various molecular approaches, such as the development of transgenic animals expressing human complement regulatory proteins such as CD59 or decay accelerating factor (DAF), to downregulate complement activation or the production of pigs lacking the xenoreactive antigen by knockout of the Gal-1,3-galactosyl transferase gene have also been attempted. A combination of these techniques together with the administration of soluble complement inhibitors such as the vaccinia virus complement control protein (VCP) may well contribute to prolong graft survival. However, various issues including the possible emergence of new viral infections have confounded the topic of xenotransplantation. Here the different modulatory approaches and agents mediating interventions in xenorejection are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
41. Humanized Recombinant Vaccinia Virus Complement Control Protein (hrVCP) with Three Amino Acid Changes, H98Y, E102K, and E120K Creating an Additional Putative Heparin Binding Site, Is 100-fold More Active Than rVCP in Blocking Both Classical and Alternative Complement Pathways
- Author
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GHEBREMARIAM, YOHANNES T., ODUNUGA, ODUTAYO O., JANSE, KRISTEN, and KOTWAL, GIRISH J.
- Subjects
VACCINIA ,VIRUS diseases in cattle ,PROTEINS ,AMINO acids ,RHEUMATOID arthritis - Abstract
Vaccinia virus complement control protein (VCP) is able to modulate the host complement system by regulating both pathways of complement activation. Efficient downregulation of complement activation depends on the ability of the regulatory protein to effectively bind the activated third (C3b) and fourth (C4b) complement components. Based on native crystallographic structure, molecular modeling, and sequence alignment with other Orthopoxviral complement control proteins (CCPs) and their host homologs, putative sites have been found on VCP as contact points for C3b/C4b. Here, we report that using site-directed mutagenesis, modified proteins have been generated. In addition, we report that the generated modified proteins with postulated contact point substitutions have shown greater ability to regulate both the classical and the alternative pathways of complement activation than the recombinant Western Reserve VCP, with one modified protein showing nearly 100-fold more potency in regulating both complement activation pathways independently. The augmented in vitro inhibitory activity of the modified protein together with the newly created putative heparin binding site suggests its promising potential as a competent therapeutic agent in modulating various complement-mediated ailments, for example, traumatic brain injury, Alzheimer's disease, rheumatoid arthritis, multiple organ dysfunction syndrome, reperfusion injury, and xenorejection. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
42. Infection and nuclear interaction in mammalian cells by 'Candidatus Berkiella cookevillensis', a novel bacterium isolated from amoebae.
- Author
-
Chamberlain, Nicholas B., Mehari, Yohannes T., Hayes, B. Jason, Roden, Colleen M., Kidane, Destaalem T., Swehla, Andrew J., Lorenzana-DeWitt, Mario A., Farone, Anthony L., Gunderson, John H., Berk, Sharon G., and Farone, Mary B.
- Subjects
MAMMALIAN cell cycle ,CANDIDATUS ,ACANTHAMOEBA polyphaga ,COXIELLA burnetii ,IMMUNOFLUORESCENCE - Abstract
Background: 'Candidatus Berkiella cookevillensis' and 'Ca. Berkiella aquae' have previously been described as intranuclear bacteria of amoebae. Both bacteria were isolated from amoebae and were described as appearing within the nuclei of Acanthamoeba polyphaga and ultimately lysing their host cells within 4 days. Both bacteria are Gammaproteobacteria in the order Legionellales with the greatest similarity to Coxiella burnetii. Neither bacterium grows axenically in artificial culture media. In this study, we further characterized 'Ca. B. cookevillensis' by demonstrating association with nuclei of human phagocytic and nonphagocytic cell lines. Results: Transmission electron microscopy (TEM) and confocal microscopy were used to confirm nuclear co-localization of 'Ca. B. cookevillensis' in the amoeba host A. polyphaga with 100% of cells having bacteria co-localized with host nuclei by 48 h. TEM and confocal microscopy demonstrated that the bacterium was also observed to be closely associated with nuclei of human U937 and THP-1 differentiated macrophage cell lines and nonphagocytic HeLa human epithelial-like cells. Immunofluorescent staining revealed that the bacteria-containing vacuole invaginates the nuclear membranes and appears to cross from the cytoplasm into the nucleus as an intact vacuole. Conclusion: Results of this study indicate that a novel coccoid bacterium isolated from amoebae can infect human cell lines by associating with the host cell nuclei, either by crossing the nuclear membranes or by deeply invaginating the nuclear membranes. When associated with the nuclei, the bacteria appear to be bound within a vacuole and replicate to high numbers by 48 h. We believe this is the first report of such a process involving bacteria and human cell lines. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
43. Magnetic field dependence of the elastic constants in Nd3Se4(abstract).
- Author
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Fütterer, H., Yohannes, T., Bach, H., Pelzl, J., and Nahm, K.
- Subjects
MAGNETIC fields ,MAGNETICS - Abstract
Presents an abstract of the study 'Magnetic Field Dependence of the Elastic Constants in Nd[sub3]Se[sub4],' by H. Fütterer, T. Yohannes, H. Bach, J. Pelzi and K. Nahm.
- Published
- 1988
44. Lansoprazole Worsens Asthma Control in Poor Metabolizers: Is Nitric Oxide Involved?
- Author
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Sukhovershin, Roman A., Ghebremariam, Yohannes T., and Cooke, John P.
- Published
- 2015
- Full Text
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45. Lansoprazole worsens asthma control in poor metabolizers: is nitric oxide involved?
- Author
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Sukhovershin, Roman A, Ghebremariam, Yohannes T, and Cooke, John P
- Published
- 2015
- Full Text
- View/download PDF
46. Pleiotropic effect of the proton pump inhibitor esomeprazole leading to suppression of lung inflammation and fibrosis.
- Author
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Ghebremariam, Yohannes T, Cooke, John P, Gerhart, William, Griego, Carol, Brower, Jeremy B, Doyle-Eisele, Melanie, Moeller, Benjamin C, Zhou, Qingtao, Ho, Lawrence, de Andrade, Joao, Raghu, Ganesh, Peterson, Leif, Rivera, Andreana, and Rosen, Glenn D
- Abstract
Background: The beneficial outcome associated with the use of proton pump inhibitors (PPIs) in idiopathic pulmonary fibrosis (IPF) has been reported in retrospective studies. To date, no prospective study has been conducted to confirm these outcomes. In addition, the potential mechanism by which PPIs improve measures of lung function and/or transplant-free survival in IPF has not been elucidated.Methods: Here, we used biochemical, cell biological and preclinical studies to evaluate regulation of markers associated with inflammation and fibrosis. In our in vitro studies, we exposed primary lung fibroblasts, epithelial and endothelial cells to ionizing radiation or bleomycin; stimuli typically used to induce inflammation and fibrosis. In addition, we cultured lung fibroblasts from IPF patients and studied the effect of esomeprazole on collagen release. Our preclinical study tested efficacy of esomeprazole in a rat model of bleomycin-induced lung injury. Furthermore, we performed retrospective analysis of interstitial lung disease (ILD) databases to examine the effect of PPIs on transplant-free survival.Results: The cell culture studies revealed that esomeprazole controls inflammation by suppressing the expression of pro-inflammatory molecules including vascular cell adhesion molecule-1, inducible nitric oxide synthase, tumor necrosis factor-alpha (TNF-α) and interleukins (IL-1β and IL-6). The antioxidant effect is associated with strong induction of the stress-inducible cytoprotective protein heme oxygenase-1 (HO1) and the antifibrotic effect is associated with potent inhibition of fibroblast proliferation as well as downregulation of profibrotic proteins including receptors for transforming growth factor β (TGFβ), fibronectin and matrix metalloproteinases (MMPs). Furthermore, esomeprazole showed robust effect in mitigating the inflammatory and fibrotic responses in a murine model of acute lung injury. Finally, retrospective analysis of two ILD databases was performed to assess the effect of PPIs on transplant-free survival in IPF patients. Intriguingly, this data demonstrated that IPF patients on PPIs had prolonged survival over controls (median survival of 3.4 vs 2 years).Conclusions: Overall, these data indicate the possibility that PPIs may have protective function in IPF by directly modulating the disease process and suggest that they may have other clinical utility in the treatment of extra-intestinal diseases characterized by inflammatory and/or fibrotic phases. [ABSTRACT FROM AUTHOR]- Published
- 2015
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47. Response to Letters Regarding Article, "Unexpected Effect of Proton Pump Inhibitors: Elevation of the Cardiovascular Risk Factor Asymmetric Dimethylarginine".
- Author
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Ghebremariam, Yohannes T., LePendu, Paea, Lee, Jerry C., Erlanson, Daniel A., Slaviero, Anna, Shah, Nigam H., Leiper, James M., and Cooke, John P.
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- 2014
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48. Vaccinia Virus Complement Control Protein (VCP) Ameliorates Kidney Damage Following Ischemia/Reperfusion Injury In Rats.
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Ghebremariam, Yohannes T., Engelbrecht, Gert, Tyler, Marilyn, Lotz, Zoe, Govender, Dhirendra, Kotwal, Girish J., and Kahn, Del
- Subjects
VACCINIA ,PROTEINS ,KIDNEY diseases ,ISCHEMIA ,REPERFUSION injury ,LABORATORY rats - Abstract
Aim: The aim of the study was to evaluate the roles of the natural VCP and the humanized recombinant VCP (hrVCP) in a renal ischemia/reperfusion (I/R) injury model. Methods: Long Evans rats weighing 422-479g were subjected to bilateral I/R injury by clamping both the renal arteries for 60 min followed by 24 h of reperfusion. The animals were randomly allocated to receive VCP, hrVCP, phosphate-buffered saline (PBS) or sham groups. Blood samples were collected and the kidneys removed for histopathological and immunohistochemical studies. Results: The biochemical studies showed that the PBS group displayed 2.7-fold and 10-fold increases in the serum urea and creatinine concentrations respectively compared to the VCP/hrVCP groups. Moreover, the histopathological study revealed severe tubular damage and aggregation of neutrophils in the PBS group compared to the focal tubular injury in the VCP and hrVCP treated animals. The immunohistochemical study displayed marked deposition of C3 in the renal tubules of the PBS group compared to the focal C3 staining in the VCP/hrVCP groups. Conclusion: The vaccinia virus complement control proteins ameliorated renal 1/R injury possibly by inhibiting the local biosynthesis of the C3 complement component. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
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