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Vanderpool AL, Durkes A. Pathology in Practice. J Am Vet Med Assoc 2019; 254:81-84. [PMID: 30668295 DOI: 10.2460/javma.254.1.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Somann JP, Albors GO, Neihouser KV, Lu KH, Liu Z, Ward MP, Durkes A, Robinson JP, Powley TL, Irazoqui PP. Chronic cuffing of cervical vagus nerve inhibits efferent fiber integrity in rat model. J Neural Eng 2017; 15:036018. [PMID: 29219123 DOI: 10.1088/1741-2552/aaa039] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Numerous studies of vagal nerve stimulation (VNS) have been published showing it to be a potential treatment for chronic inflammation and other related diseases and disorders. Studies in recent years have shown that electrical stimulation of the vagal efferent fibers can artificially modulate cytokine levels and reduce systematic inflammation. Most VNS research in the treatment of inflammation have been acute studies on rodent subjects. Our study tested VNS on freely moving animals by stimulating and recording from the cervical vagus with nerve cuff electrodes over an extended period of time. APPROACH We used methods of electrical stimulation, retrograde tracing (using Fluorogold) and post necropsy histological analysis of nerve tissue, flow cytometry to measure plasma cytokine levels, and MRI scanning of gastric emptying. This novel combination of methods allowed examination of physiological aspects of VNS previously unexplored. MAIN RESULTS Through our study of 53 rat subjects, we found that chronically cuffing the left cervical vagus nerve suppressed efferent Fluorogold transport in 43 of 44 animals (36 showed complete suppression). Measured cytokine levels and gastric emptying rates concurrently showed nominal differences between chronically cuffed rats and those tested with similar acute methods. Meanwhile, results of electrophysiological and histological tests of the cuffed nerves revealed them to be otherwise healthy, consistent with previous literature. SIGNIFICANCE We hypothesize that due to these unforeseen and unexplored physiological consequences of the chronically cuffed vagus nerve in a rat, that inflammatory modulation and other vagal effects by VNS may become unreliable in chronic studies. Given our findings, we submit that it would benefit the VNS community to re-examine methods used in previous literature to verify the efficacy of the rat model for chronic VNS studies.
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Affiliation(s)
- Jesse P Somann
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, United States of America. Center for Implantable Devices (CID), Purdue University, West Lafayette, Indiana, United States of America
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Durkes A, Sivasankar MP. A Method to Administer Agents to the Larynx in an Awake Large Animal. J Speech Lang Hear Res 2017; 60:3171-3176. [PMID: 29098280 PMCID: PMC5945077 DOI: 10.1044/2017_jslhr-s-17-0040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/12/2017] [Accepted: 04/17/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE This research note describes an adapted experimental methodology to administer an exogenous agent to the larynx and upper airway of awake animals. The exogenous agent could be a perturbation. In the current study, the agent was isotonic saline. Isotonic saline was selected because it is safe, of similar composition to extracellular fluid, and used in voice studies. The described approach allowed large animals such as pigs to be comfortably restrained without chemical sedation or anesthesia for extended periods while receiving the agent. METHOD Six Sinclair pigs were successfully trained with positive reinforcement to voluntarily enter and then be restrained in a Panepinto Sling. Once restrained, the pigs accepted a nose cone that delivered nebulized isotonic saline. This procedure was repeated 3 times per day for 20 days. At the end of the study, the larynx and airway tissues were excised and examined using histology and transmission electron microscopy. RESULTS Pathology related to the procedure (i.e., nebulized inhaled isotonic saline or stress) was not identified in any examined tissues. CONCLUSIONS This methodology allowed for repeated application of exogenous agents to awake, unstressed animals. This method can be used repeatedly in the laboratory to test various therapeutics for safety, toxicity, and dosage. Future studies will specifically manipulate the type of agent to further our understanding of laryngeal pathobiology.
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Affiliation(s)
- Abigail Durkes
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN
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Connell S, Li J, Durkes A, Freeman L. Application of Hyperosmotic Nanoemulsions in Wound Healing: Partial Thickness Injury Model in Swine. Adv Wound Care (New Rochelle) 2017; 6:153-165. [PMID: 28507786 DOI: 10.1089/wound.2016.0689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/25/2016] [Indexed: 01/22/2023] Open
Abstract
Objective: In this work, we introduce a novel hyperosmotic nanoemulsion (HNE) topical agent for use in wound healing. These topical emulsion complexes combine a lipophilic thymol nanoemulsion with a hyperosmotic saccharide matrix. This combination has been previously shown to possess synergistic antimicrobial activity against a host of common and drug-resistant pathogens in vitro. Approach: In this study, we present additional data to assess the safety and efficacy of these emulsions in a partial thickness injury model in swine. Ten wounds sized 2 × 3.5 cm were created in 18 pigs using an electrodermatome set at a depth of 0.76 mm. The wounds were subsequently contaminated with a cocktail of Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Candida albicans at 5 × 107 total colony forming unit per wound. Treatments were subdivided in the control group and emulsion concentrations at 0.0%, 0.01%, 0.03%, and 0.063% thymol content. Longitudinal metrics for wound healing included rate of reepithelialization, wound bed color measurements, amount of wound exudate, wound swab culture data, and histological examination at 4, 7, and 14 days. The cosmetics of the healed wound were obtained at day 14 with three-dimensional photogrammetry. Results: Experimental results showed that HNE reduced the wound level bacteria count by ∼0.5-1 log versus controls after 24 h. The amount of pathogen reduction was weakly correlated to the concentration of the emulsion. In addition, all HNE groups maintained a moist wound environment and showed increased fibrin formation and improved hemostatic response. Innovation: No significant difference in the rate of reepithelialization or wound closure was found between treatment concentrations and control groups. HNE treatment did not demonstrate any adverse host tissue response. Conclusion: These results suggest HNE may be a candidate for reducing wound bacterial counts without compromising reepithelialization.
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Affiliation(s)
| | - Jianming Li
- Department of Basic Medical Sciences, Center for Paralysis Research, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana
| | - Abigail Durkes
- Comparative Pathobiology Department, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana
| | - Lynetta Freeman
- Weldon School of Biomedical Engineering, College of Engineering, Purdue University, West Lafayette, Indiana
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana
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Bi P, Yue F, Karki A, Castro B, Wirbisky SE, Wang C, Durkes A, Elzey BD, Andrisani OM, Bidwell CA, Freeman JL, Konieczny SF, Kuang S. Notch activation drives adipocyte dedifferentiation and tumorigenic transformation in mice. J Exp Med 2016; 213:2019-37. [PMID: 27573812 PMCID: PMC5030803 DOI: 10.1084/jem.20160157] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 07/26/2016] [Indexed: 12/25/2022] Open
Abstract
Adipocyte-specific activation of Notch signaling suppresses lipid metabolism pathways that provide ligands to Pparγ, leading to adipocyte dedifferentiation and development of liposarcomas (LPSs) resembling human dedifferentiated LPSs with complete penetrance. Pparγ ligand supplementation prevents liposarcoma development. Liposarcomas (LPSs) are the most common soft-tissue cancer. Because of the lack of animal models, the cellular origin and molecular regulation of LPS remain unclear. Here, we report that mice with adipocyte-specific activation of Notch signaling (Ad/N1ICD) develop LPS with complete penetrance. Lineage tracing confirms the adipocyte origin of Ad/N1ICD LPS. The Ad/N1ICD LPS resembles human dedifferentiated LPS in histological appearance, anatomical localization, and gene expression signature. Before transformation, Ad/N1ICD adipocytes undergo dedifferentiation that leads to lipodystrophy and metabolic dysfunction. Although concomitant Pten deletion normalizes the glucose metabolism of Ad/N1ICD mice, it dramatically accelerates the LPS prognosis and malignancy. Transcriptomes and lipidomics analyses indicate that Notch activation suppresses lipid metabolism pathways that supply ligands to Pparγ, the master regulator of adipocyte homeostasis. Accordingly, synthetic Pparγ ligand supplementation induces redifferentiation of Ad/N1ICD adipocytes and tumor cells, and prevents LPS development in Ad/N1ICD mice. Importantly, the Notch target HES1 is abundantly expressed in human LPS, and Notch inhibition suppresses the growth of human dedifferentiated LPS xenografts. Collectively, ectopic Notch activation is sufficient to induce dedifferentiation and tumorigenic transformation of mature adipocytes in mouse.
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Affiliation(s)
- Pengpeng Bi
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907
| | - Feng Yue
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907
| | - Anju Karki
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Beatriz Castro
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907
| | - Sara E Wirbisky
- School of Health Sciences, Purdue University, West Lafayette, IN 47907
| | - Chao Wang
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907
| | - Abigail Durkes
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907
| | - Bennett D Elzey
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907 Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Ourania M Andrisani
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907 Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | | | - Jennifer L Freeman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907 Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Stephen F Konieczny
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907 Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 Center for Cancer Research, Purdue University, West Lafayette, IN 47907
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Connell S, Li J, Durkes A, Zaroura M, Shi R. Nondermal irritating hyperosmotic nanoemulsions reduce treatment times in a contamination model of wound healing. Wound Repair Regen 2016; 24:669-78. [DOI: 10.1111/wrr.12436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 04/01/2016] [Indexed: 11/28/2022]
Affiliation(s)
| | - Jianming Li
- Medtric Biotech, LLCWest Lafayette Indiana
- Center for Paralysis Research, Purdue UniversityWest Lafayette Indiana47907
| | - Abigail Durkes
- Comparative Pathobiology Department, College of Veterinary MedicinePurdue UniversityWest Lafayette Indiana47907
| | | | - Riyi Shi
- Department of Basic Medical Sciences, College of Veterinary MedicinePurdue UniversityWest Lafayette Indiana47907
- Weldon School of Biomedical Engineering, College of EngineeringPurdue UniversityWest Lafayette Indiana
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Durkes A, Sivasankar MP. In vivo investigation of acidified pepsin exposure to porcine vocal fold epithelia. Laryngoscope 2015; 126:E12-7. [PMID: 26153224 DOI: 10.1002/lary.25478] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/07/2015] [Accepted: 06/08/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVES/HYPOTHESIS The study objective was to investigate epithelial changes in response to direct, repeated, acidified pepsin exposures in an in vivo porcine model. We hypothesized that 12 acidified pepsin applications to simulate reflux would elicit a vocal fold response characterized by inflammation, epithelial proliferation, and increased intercellular space, as well as changes in the gene expression of epithelial junctional proteins, ion transporter proteins, and proinflammatory cytokines. STUDY DESIGN Prospective, in vivo study. METHODS Pigs received acidified pepsin (pH = 4) or saline (sham) applied directly to vocal folds. Larynges were collected following three exposures per week for 4 weeks. Vocal fold tissue morphology, collagen, and elastin were evaluated histologically. Gene expression of E-cadherin, zona occludens-1, cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, interleukin-1β, tumor necrosis factor-α, and interferon-γ were measured. Ultrastructural alterations, epithelial intercellular space diameter, and microridge height were measured using transmission electron microscopy. RESULTS There were no significant differences in histology, gene transcripts, epithelial ultrastructure, intercellular space, and microridge height after acidified pepsin exposure. CONCLUSIONS Twelve simulated reflux challenges were insufficient to elicit epithelial changes, demonstrating the resistance of healthy vocal folds to direct, repeated acidified pepsin exposures. These data increase our understanding of healthy vocal fold defenses and lay the groundwork for a prospective, uninjured, nonsurgical, laryngopharyngeal reflux model where pigs can be exposed directly to acidified pepsin.
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Affiliation(s)
- Abigail Durkes
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, U.S.A
| | - M Preeti Sivasankar
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana, U.S.A
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Abstract
OBJECTIVES Bicarbonate is critical for acid-base tissue homeostasis. In this study we investigated the role of bicarbonate ion transport in vocal fold epithelial defense to acid challenges. Acidic insults to the larynx are common in gastric reflux, carcinogenesis and metastasis, and acute inflammation. METHODS Ion transport was measured in viable porcine vocal fold epithelium. First, 18 vocal folds were exposed to either the carbonic anhydrase antagonist acetazolamide or to vehicle. Second, 32 vocal folds were exposed to either a control buffer or a bicarbonate-free buffer on their luminal or basolateral surface or both. Third, 32 vocal folds were challenged with acid in the presence of bicarbonate-free or control buffer. RESULTS The vocal fold transepithelial resistance was greater than 300 Ω*cm(2), suggesting robust barrier integrity. Ion transport did not change after exposure to acetazolamide (p > 0.05). Exposure to bicarbonate-free buffer did not compromise vocal fold ion transport (p > 0.05). Ion transport increased after acid challenge. This increase approached statistical significance and was the greatest for the control buffer and for the bicarbonate-free buffer applied to the basolateral surface. CONCLUSIONS Bicarbonate secretion may contribute to vocal fold defense against acid challenge. Our data offer a potential novel role for bicarbonate as a therapeutic agent to reduce pH abnormalities in the larynx and prevent associated pathological changes.
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Affiliation(s)
- Abigail Durkes
- Department of Comparative Pathobiology, College of Veterinary Medicine (Durkes), Purdue University, West Lafayette, Indiana
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Abstract
This study evaluates the immunoreactivity of 12 sex cord-stromal tumors of nonhuman primates (11 granulosa cell tumors and 1 luteoma). The markers selected are used in the characterization of gonadal tumors in dogs and other species, including cytokeratins AE1/AE3, GATA-4, inhibin-α, neuron-specific enolase, protein gene product 9.5, and vimentin. A normal nonhuman primate ovary was used as a control and to optimize immunolabeling. Staining was graded as follows: 0 (nonstaining), 1+ (< 10% positive cells), 2+ (10%-50% positive cells), and 3+ (> 50% positive cells). Calretinin, GATA-4, neuron-specific enolase, and vimentin were the most consistently expressed markers (12 of 12). Cytokeratins AE1/AE3 were also consistently expressed (11 of 12). Inhibin-α and protein gene product 9.5 were expressed in 8 and 10 sex cord-stromal tumors, respectively. Results indicate that immunoreactivity of nonhuman primate sex cord-stromal tumors is similar to that observed in other species and that calretinin, GATA-4, and neuron-specific enolase are the most consistently expressed markers in nonhuman primate sex cord-stromal tumors.
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Affiliation(s)
- A Durkes
- Department of Comparative Pathobiology, Purdue University, 406 South University, West Lafayette, IN 47907, USA
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Abstract
The pathophysiology of spinal cord injury (SCI) is characterized by the initial, primary injury followed by secondary injury processes in which oxidative stress is a critical component. Secondary injury processes not only exacerbate pathology at the site of primary injury, but also result in spreading of injuries to the adjacent, otherwise healthy tissue. The lipid peroxidation byproduct acrolein has been implicated as one potential mediator of secondary injury. To further and rigorously elucidate the role of acrolein in secondary injury, a unique ex vivo model is utilized to isolate the detrimental effects of mechanical injury from toxins such as acrolein that are produced endogenously following SCI. We demonstrate that (i) acrolein-Lys adducts are capable of diffusing from compressed tissue to adjacent, otherwise uninjured tissue; (ii) secondary injury by itself produces significant membrane damage and increased superoxide production; and (iii) these injuries are significantly attenuated by the acrolein scavenger hydralazine. Furthermore, hydralazine treatment results in significantly less membrane damage 2 h following compression injury, but not immediately after. These findings support our hypothesis that, following SCI, acrolein is increased to pathologic concentrations, contributes significantly to secondary injury, and thus represents a novel target for scavenging to promote improved recovery.
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Affiliation(s)
- Kristin Hamann
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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