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Shrestha S, Wang B, Dutta PK. Commercial Silver-Based Dressings: In Vitro and Clinical Studies in Treatment of Chronic and Burn Wounds. Antibiotics (Basel) 2024; 13:910. [PMID: 39335083 PMCID: PMC11429284 DOI: 10.3390/antibiotics13090910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2024] [Revised: 09/17/2024] [Accepted: 09/20/2024] [Indexed: 09/30/2024] Open
Abstract
Chronic wounds are a major health problem because of delayed healing, causing hardships for the patient. The infection present in these wounds plays a role in delayed wound healing. Silver wound dressings have been used for decades, beginning in the 1960s with silver sulfadiazine for infection prevention for burn wounds. Since that time, there has been a large number of commercial silver dressings that have obtained FDA clearance. In this review, we examine the literature involving in vitro and in vivo (both animal and human clinical) studies with commercial silver dressings and attempt to glean the important characteristics of these dressings in treating infected wounds. The primary presentation of the literature is in the form of detailed tables. The narrative part of the review focuses on the different types of silver dressings, including the supporting matrix, the release characteristics of the silver into the surroundings, and their toxicity. Though there are many clinical studies of chronic and burn wounds using silver dressings that we discuss, it is difficult to compare the performances of the dressings directly because of the differences in the study protocols. We conclude that silver dressings can assist in wound healing, although it is difficult to provide general treatment guidelines. From a wound dressing point of view, future studies will need to focus on new delivery systems for silver, as well as the type of matrix in which the silver is deposited. Clearly, adding other actives to enhance the antimicrobial activity, including the disruption of mature biofilms is of interest. From a clinical point of view, the focus needs to be on the wound healing characteristics, and thus randomized control trials will provide more confidence in the results. The application of different wound dressings for specific wounds needs to be clarified, along with the application protocols. It is most likely that no single silver-based dressing can be used for all wounds.
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Affiliation(s)
| | - Bo Wang
- ZeoVation Inc., Columbus, OH 43212, USA; (S.S.); (B.W.)
| | - Prabir K. Dutta
- ZeoVation Inc., Columbus, OH 43212, USA; (S.S.); (B.W.)
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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2
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Rodrigues AE, Dolivo DM, Hou C, Li Y, Sun LS, Mustoe TA, Hong SJ, Galiano RD. Influence of Staphylococcus aureus Infection on Partially Ischemic Excisional Skin Wounds. Adv Med 2024; 2024:2281747. [PMID: 39345350 PMCID: PMC11438516 DOI: 10.1155/2024/2281747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 08/31/2024] [Indexed: 10/01/2024] Open
Abstract
Background Skin wounds, whether medically or incidentally induced, are always at a risk of becoming infected, but the infection risks are greater when the wounds are recovering under ischemic, poorly perfused conditions. Staphylococcus aureus, which frequently infects cutaneous and soft tissue, can infect to a greater extent when wounds are poorly perfused. Bad as this may be, both MSSA and MRSA strains of S. aureus can cause severe infections, with MRSA being considered more aggressive. Methods In this study, we used a lagomorph ear excisional wound model to initially test the influence of partial ischemia on uninfected wound healing. We then subsequently test the same ischemic injury model under an active MSSA infection and compared these wounds against normally perfused MSSA-infected wounds. Lastly, we test whether differences in healing exist between MSSA-infected and MRSA-infected wounds, both under the same ischemic model. Results The data suggest that partial ischemia considerably reduces healing of noninfected wounds (epithelial gap P=∗∗∗∗, granulation gap P=∗∗∗, and granulation area P=∗∗∗∗). Similarly, partial ischemic wounds coupled with MSSA infection display healing impairments against likewise-infected wounds healing under normal perfusion (epithelial gap P=∗, granulation gap P=∗, and granulation area P=∗∗). No significant differences were observed between MSSA-infected and MRSA-infected wounds healing under ischemia. Conclusion The data produced quantitative differences in healing under various conditions consequent to ischemia and S. aureus infection. Although it is well recognized that ischemia and infection adversely influence healing, by testing these conditions, we determined the detrimental magnitude such circumstances inflict on skin healing, thereby providing a relative reference to compare and gauge when met with similar conditions clinically.
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Affiliation(s)
- Adrian E Rodrigues
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
| | - David M Dolivo
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
| | - Chun Hou
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
- Department of Plastic and Cosmetic Surgery First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yingxing Li
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
| | - Lauren S Sun
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
| | - Thomas A Mustoe
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
| | - Seok Jong Hong
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
| | - Robert D Galiano
- Department of Surgery, Division of Plastic Surgery Northwestern University Feinberg School of Medicine, Chicago, USA
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3
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Pignet AL, Schellnegger M, Hecker A, Kamolz LP, Kotzbeck P. Modeling Wound Chronicity In Vivo: The Translational Challenge to Capture the Complexity of Chronic Wounds. J Invest Dermatol 2024; 144:1454-1470. [PMID: 38483357 DOI: 10.1016/j.jid.2023.11.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 06/24/2024]
Abstract
In an aging society with common lifestyle-associated health issues such as obesity and diabetes, chronic wounds pose a frequent challenge that physicians face in everyday clinical practice. Therefore, nonhealing wounds have attracted much scientific attention. Several in vitro and in vivo models have been introduced to deepen our understanding of chronic wound pathogenesis and amplify therapeutic strategies. Understanding how wounds become chronic will provide insights to reverse or avoid chronicity. Although choosing a suitable model is of utmost importance to receive valuable outcomes, an ideal in vivo model capturing the complexity of chronic wounds is still missing and remains a translational challenge. This review discusses the most relevant mammalian models for wound healing studies and provides guidance on how to implement the hallmarks of chronic wounds. It highlights the benefits and pitfalls of established models and maps out future avenues for research.
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Affiliation(s)
- Anna-Lisa Pignet
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria; COREMED - Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH, Graz, Austria; Research Unit for Tissue Repair and Reconstruction, Medical University of Graz, Graz, Austria
| | - Marlies Schellnegger
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria; COREMED - Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH, Graz, Austria; Research Unit for Tissue Repair and Reconstruction, Medical University of Graz, Graz, Austria.
| | - Andrzej Hecker
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria; COREMED - Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH, Graz, Austria; Research Unit for Tissue Repair and Reconstruction, Medical University of Graz, Graz, Austria
| | - Lars-Peter Kamolz
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria; COREMED - Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH, Graz, Austria
| | - Petra Kotzbeck
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria; COREMED - Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH, Graz, Austria; Research Unit for Tissue Repair and Reconstruction, Medical University of Graz, Graz, Austria
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4
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Reiche E, Keller PR, Soares V, Schuster CR, Rahmayanti S, Mroueh J, Mroueh V, Billaud M, Hu S, Hoover-Watson H, Lian CG, Tan Y, Doloff JC, Newell-Fugate AE, Coon D. Androgenic steroids induce pathologic scarring in a preclinical porcine model via dysfunctional extracellular matrix deposition. FASEB J 2024; 38:e23561. [PMID: 38530321 DOI: 10.1096/fj.202302144rrr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/19/2024] [Accepted: 03/01/2024] [Indexed: 03/27/2024]
Abstract
Hypertrophic scarring is a major source of morbidity. Sex hormones are not classically considered modulators of scarring. However, based on increased frequency of hypertrophic scarring in patients on testosterone, we hypothesized that androgenic steroids induce abnormal scarring and developed a preclinical porcine model to explore these effects. Mini-swine underwent castration, received no testosterone (noT) or biweekly testosterone therapy (+T), and underwent excisional wounding. To create a delayed wound healing model, a subset of wounds were re-excised at 2 weeks. Scars from postoperative day 42 (POD42) and delayed wounds (POD28) were harvested 6 weeks after initial wounding for analysis via histology, bulk RNA-seq, and mechanical testing. Histologic analysis of scars from +T animals showed increased mean fibrosis area (16 mm2noT, 28 mm2+T; p = .007) and thickness (0.246 mm2noT, 0.406 mm2+T; p < .001) compared to noT. XX+T and XY+T scars had greater tensile burst strength (p = .024 and p = .013, respectively) compared to noT swine. Color deconvolution analysis revealed greater deposition of type I and type III collagen as well as increased collagen type I:III ratio in +T scars. Dermatopathologist histology scoring showed that +T exposure was associated with worse overall scarring (p < .05). Gene ontology analysis found that testosterone exposure was associated with upregulation of cellular metabolism and immune response gene sets, while testosterone upregulated pathways related to keratinization and laminin formation on pathway analysis. In conclusion, we developed a preclinical porcine model to study the effects of the sex hormone testosterone on scarring. Testosterone induces increased scar tissue deposition and appears to increase physical strength of scars via supraphysiologic deposition of collagen and other ECM factors. The increased burst strength seen in both XX and XY animals suggests that hormone administration has a strong influence on scar mechanical properties independent of chromosomal sex. Anti-androgen topical therapies may be a promising future area of research.
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Affiliation(s)
- Erik Reiche
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Patrick R Keller
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Vance Soares
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Calvin R Schuster
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Siti Rahmayanti
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
| | - Jessica Mroueh
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
| | - Vanessa Mroueh
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
| | - Marie Billaud
- Division of Thoracic and Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sophia Hu
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
| | - Hunter Hoover-Watson
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
| | - Christine G Lian
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Yu Tan
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
| | - Joshua C Doloff
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Annie E Newell-Fugate
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, Texas, USA
| | - Devin Coon
- Division of Plastic Surgery, Brigham and Women's Hospital - Harvard Medical School, Boston, Massachusetts, USA
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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5
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Saeed S, Martins-Green M. Assessing Animal Models to Study Impaired and Chronic Wounds. Int J Mol Sci 2024; 25:3837. [PMID: 38612647 PMCID: PMC11011258 DOI: 10.3390/ijms25073837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
Impaired healing wounds do not proceed through the normal healing processes in a timely and orderly manner, and while they do eventually heal, their healing is not optimal. Chronic wounds, on the other hand, remain unhealed for weeks or months. In the US alone, chronic wounds impact ~8.5 million people and cost ~USD 28-90 billion per year, not accounting for the psychological and physical pain and emotional suffering that patients endure. These numbers are only expected to rise in the future as the elderly populations and the incidence of comorbidities such as diabetes, hypertension, and obesity increase. Over the last few decades, scientists have used a variety of approaches to treat chronic wounds, but unfortunately, to date, there is no effective treatment. Indeed, while there are thousands of drugs to combat cancer, there is only one single drug approved for the treatment of chronic wounds. This is in part because wound healing is a very complex process involving many phases that must occur sequentially and in a timely manner. Furthermore, models that fully mimic human chronic wounds have not been developed. In this review, we assess various models currently being used to study the biology of impaired healing and chronic non-healing wounds. Among them, this paper also highlights one model which shows significant promise; this model uses aged and obese db/db-/- mice and the chronic wounds that develop show characteristics of human chronic wounds that include increased oxidative stress, chronic inflammation, damaged microvasculature, abnormal collagen matrix deposition, a lack of re-epithelialization, and the spontaneous development of multi-bacterial biofilm. We also discuss how important it is that we continue to develop chronic wound models that more closely mimic those of humans and that can be used to test potential treatments to heal chronic wounds.
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Affiliation(s)
| | - Manuela Martins-Green
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, CA 92521, USA;
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6
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Ma J, Song R, Liu C, Cao G, Zhang G, Wu Z, Zhang H, Sun R, Chen A, Wang Y, Yin S. Single-cell RNA-Seq analysis of diabetic wound macrophages in STZ-induced mice. J Cell Commun Signal 2023; 17:103-120. [PMID: 36445632 PMCID: PMC10030741 DOI: 10.1007/s12079-022-00707-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 10/15/2022] [Indexed: 12/03/2022] Open
Abstract
The crucial role of macrophages in the healing of chronic diabetic wounds is widely known, but previous in vitro classification and marker genes of macrophages may not be fully applicable to cells in the microenvironment of chronic wounds. The heterogeneity of macrophages was studied and classified at the single-cell level in a chronic wound model. We performed single-cell sequencing of CD45 + immune cells within the wound edge and obtained 17 clusters of cells, including 4 clusters of macrophages. One of these clusters is a previously undescribed population of macrophages possessing osteoclast gene expression, for which analysis of differential genes revealed possible functions. We also analysed the differences in gene expression between groups of macrophages in the control and diabetic wound groups at different sampling times. We described the differentiation profile of mononuclear macrophages, which has provided an important reference for the study of immune-related mechanisms in diabetic chronic wounds.
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Affiliation(s)
- Jiaxu Ma
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Ru Song
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Chunyan Liu
- Department of Plastic Surgery, Shandong Provincial Qianfoshan Hospital, The First Affiliated Hospital of Shandong First Medical University, 250014, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Guoqi Cao
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Guang Zhang
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Zhenjie Wu
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Huayu Zhang
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Rui Sun
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Aoyu Chen
- Department of Plastic Surgery, Shandong Provincial Qianfoshan Hospital, The First Affiliated Hospital of Shandong First Medical University, 250014, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
| | - Yibing Wang
- Department of Plastic Surgery, Cheeloo College of Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, P. R. China.
- Department of Plastic Surgery, Shandong Provincial Qianfoshan Hospital, The First Affiliated Hospital of Shandong First Medical University, 250014, Jinan, Shandong, P. R. China.
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China.
| | - Siyuan Yin
- Department of Plastic Surgery, Shandong Provincial Qianfoshan Hospital, The First Affiliated Hospital of Shandong First Medical University, 250014, Jinan, Shandong, P. R. China
- Jinan Clinical Research Center for Tissue Engineering Skin Regeneration and Wound Repair, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, 250014, Jinan, P. R. China
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7
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Tan MLL, Chin JS, Madden L, Becker DL. Challenges faced in developing an ideal chronic wound model. Expert Opin Drug Discov 2023; 18:99-114. [PMID: 36573018 DOI: 10.1080/17460441.2023.2158809] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Chronic wounds are a major drain on healthcare resources and can lead to substantial reductions in quality of life for those affected. Moreover, they often precede serious events such as limb amputations and premature death. In the long run, this burden is likely to escalate with an ageing population and lifestyle diseases such as obesity. Thus far, the identification of beneficial therapeutics against chronic wounds have been hindered by the lack of an ideal chronic wound animal model. Although animal models of delayed healing have been developed, none of these models fully recapitulate the complexity of the human chronic wound condition. Furthermore, most animals do not develop chronic wounds. Only the thoroughbred racehorse develops chronic ulcers. AREAS COVERED In this review, the different characteristics of chronic wounds that highlight its complexity are described. In addition, currently available models reflecting different aspects of chronic wound pathology and their relevance to human chronic wounds are discussed. This article concludes by listing relevant features representative of an ideal chronic wound model. Additionally, alternative approaches for the development of chronic wound models are discussed. EXPERT OPINION Delayed models of healing, including the streptozotocin diabetic model, skin flap model and magnet-induced IR models have emerged. While these models have been widely adopted for preclinical therapeutic testing, their relevance towards human chronic wounds remains debatable. In particular, current delayed healing models often fail to fully incorporate the key characteristics of chronic ulcers. Ultimately, more representative models are required to expedite the advancement of novel therapeutics to the clinic.
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Affiliation(s)
- Mandy Li Ling Tan
- Nanyang Institute of Health Technologies, Interdisciplinary Graduate School, Nanyang Technological University, 639798, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, 308232, Singapore
| | - Jiah Shin Chin
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232, Singapore
| | - Leigh Madden
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232, Singapore
| | - David L Becker
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232, Singapore.,Skin Research Institute Singapore, Clinical Sciences Building, 11 Mandalay Road, 308232, Singapore.,National Skin Centre, Mandalay Road, Singapore
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8
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Patil P, Russo KA, McCune JT, Pollins AC, Cottam MA, Dollinger BR, DeJulius CR, Gupta MK, D'Arcy R, Colazo JM, Yu F, Bezold MG, Martin JR, Cardwell NL, Davidson JM, Thompson CM, Barbul A, Hasty AH, Guelcher SA, Duvall CL. Reactive oxygen species-degradable polythioketal urethane foam dressings to promote porcine skin wound repair. Sci Transl Med 2022; 14:eabm6586. [PMID: 35442705 PMCID: PMC10165619 DOI: 10.1126/scitranslmed.abm6586] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Porous, resorbable biomaterials can serve as temporary scaffolds that support cell infiltration, tissue formation, and remodeling of nonhealing skin wounds. Synthetic biomaterials are less expensive to manufacture than biologic dressings and can achieve a broader range of physiochemical properties, but opportunities remain to tailor these materials for ideal host immune and regenerative responses. Polyesters are a well-established class of synthetic biomaterials; however, acidic degradation products released by their hydrolysis can cause poorly controlled autocatalytic degradation. Here, we systemically explored reactive oxygen species (ROS)-degradable polythioketal (PTK) urethane (UR) foams with varied hydrophilicity for skin wound healing. The most hydrophilic PTK-UR variant, with seven ethylene glycol (EG7) repeats flanking each side of a thioketal bond, exhibited the highest ROS reactivity and promoted optimal tissue infiltration, extracellular matrix (ECM) deposition, and reepithelialization in porcine skin wounds. EG7 induced lower foreign body response, greater recruitment of regenerative immune cell populations, and resolution of type 1 inflammation compared to more hydrophobic PTK-UR scaffolds. Porcine wounds treated with EG7 PTK-UR foams had greater ECM production, vascularization, and resolution of proinflammatory immune cells compared to polyester UR foam-based NovoSorb Biodegradable Temporizing Matrix (BTM)-treated wounds and greater early vascular perfusion and similar wound resurfacing relative to clinical gold standard Integra Bilayer Wound Matrix (BWM). In a porcine ischemic flap excisional wound model, EG7 PTK-UR treatment led to higher wound healing scores driven by lower inflammation and higher reepithelialization compared to NovoSorb BTM. PTK-UR foams warrant further investigation as synthetic biomaterials for wound healing applications.
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Affiliation(s)
- Prarthana Patil
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Katherine A Russo
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Joshua T McCune
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Alonda C Pollins
- Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Matthew A Cottam
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bryan R Dollinger
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Carlisle R DeJulius
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Mukesh K Gupta
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Richard D'Arcy
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Juan M Colazo
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Mariah G Bezold
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - John R Martin
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Nancy L Cardwell
- Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Jeffrey M Davidson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Callie M Thompson
- Vanderbilt Burn Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Adrian Barbul
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37212, USA.,Department of Surgery, Veterans Administration Medical Center, Nashville, TN 37212, USA
| | - Alyssa H Hasty
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212, USA
| | - Scott A Guelcher
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA.,Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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9
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Das A, Madeshiya AK, Biswas N, Ghosh N, Gorain M, Rawat A, Mahajan SP, Khanna S, Sen CK, Roy S. Oncostatin M Improves Cutaneous Wound Re-Epithelialization and Is Deficient under Diabetic Conditions. J Invest Dermatol 2022; 142:679-691.e3. [PMID: 34534575 PMCID: PMC8860865 DOI: 10.1016/j.jid.2021.04.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/03/2021] [Accepted: 04/12/2021] [Indexed: 11/29/2022]
Abstract
Impaired re-epithelialization characterized by hyperkeratotic nonmigratory wound epithelium is a hallmark of nonhealing diabetic wounds. In chronic wounds, the copious release of oncostatin M (OSM) from wound macrophages is evident. OSM is a potent keratinocyte (KC) activator. This work sought to understand the signal transduction pathway responsible for wound re-epithelialization, the primary mechanism underlying wound closure. Daily topical treatment of full-thickness excisional wounds of C57BL/6 mice with recombinant murine OSM improved wound re-epithelialization and accelerated wound closure by bolstering KC proliferation and migration. OSM activated the Jak-signal transducer and activator of transcription pathway as manifested by signal transducer and activator of transcription 3 phosphorylation. Such signal transduction in the human KC induced TP63, the master regulator of KC function. Elevated TP63 induced ITGB1, a known effector of KC migration. In diabetic wounds, OSM was more abundant than the level in nondiabetic wounds. However, in diabetic wounds, OSM activity was compromised by glycation. Aminoguanidine, a deglycation agent, rescued the compromised KC migration caused by glycated OSM. Finally, topical application of recombinant OSM improved KC migration and accelerated wound closure in db/db mice. This work recognizes that despite its abundance at the wound site, OSM is inactivated by glycation, and topical delivery of exogenous OSM is likely to be productive in accelerating diabetic wound closure.
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Affiliation(s)
- Amitava Das
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Amit K. Madeshiya
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Nirupam Biswas
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Nandini Ghosh
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Mahadeo Gorain
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Atul Rawat
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Sanskruti P. Mahajan
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Savita Khanna
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Chandan K. Sen
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN, 46202
| | - Sashwati Roy
- Department of Surgery, IU Health Comprehensive Wound Center, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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10
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Lovasova V, Bem R, Chlupac J, Dubsky M, Husakova J, Nemcova A, Fronek J. Animal experimental models of ischemic wounds - A review of literature. Wound Repair Regen 2022; 30:268-281. [PMID: 35138685 DOI: 10.1111/wrr.12996] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 11/23/2021] [Accepted: 01/16/2022] [Indexed: 02/01/2023]
Abstract
Critical limb ischemia is a serious form of peripheral arterial disease (PAD). The consequences of lower limb ischemia are pain, claudication and chronic non-healing wounds. Patients with diabetes are especially at a high risk for developing non-healing ulcers. The most serious complication is major amputation. For this reason, there is a significant medical requirement to develop new therapies in order to prevent the progression of PAD. For research purposes, it is crucial to find an appropriate model of chronic ischemia to explore the processes of wound healing. According to recently acquired information, rodents are currently the most commonly used animals in these types of studies. The main advantage of using small animals is the low financial cost due to the relatively small demand for food, water and living space. The disadvantage is their anatomy, which is different from that of humans. Larger animals have a more human-like anatomy and physiology, but they require more expense and space for housing. A bipedicle skin flap and its modifications are popular models for ischemic wounds. In order to secure healing through re-epithelisation, as opposed to contraction in rodents, there is a need to remove the panniculus carnosus muscle. Wounds in other experimental animals heal primarily through re-epithelisation. The application of a silicone mesh underneath the flap prevents vascular regrowth in ischemic tissue. There is an ongoing effort to create in vivo diabetic models for chronic ulcer research. This work presents an overview of existing animal models of ischemic wounds.
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Affiliation(s)
- Veronika Lovasova
- Transplant Surgery Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.,Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Robert Bem
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Jaroslav Chlupac
- Transplant Surgery Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.,Department of Anatomy, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Michal Dubsky
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.,First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jitka Husakova
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.,First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Andrea Nemcova
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Jiri Fronek
- Transplant Surgery Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.,Department of Anatomy, Second Faculty of Medicine, Charles University, Prague, Czech Republic.,First Faculty of Medicine, Charles University, Prague, Czech Republic
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11
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Miles RR, Amin PH, Diaz MB, Misra J, Aukerman E, Das A, Ghosh N, Guith T, Knierman MD, Roy S, Spandau DF, Wek RC. The eIF2 kinase GCN2 directs keratinocyte collective cell migration during wound healing via coordination of reactive oxygen species and amino acids. J Biol Chem 2021; 297:101257. [PMID: 34597669 PMCID: PMC8554533 DOI: 10.1016/j.jbc.2021.101257] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/25/2022] Open
Abstract
Healing of cutaneous wounds requires the collective migration of epithelial keratinocytes to seal the wound bed from the environment. However, the signaling events that coordinate this collective migration are unclear. In this report, we address the role of phosphorylation of eukaryotic initiation factor 2 (eIF2) and attendant gene expression during wound healing. Wounding of human keratinocyte monolayers in vitro led to the rapid activation of the eIF2 kinase GCN2. We determined that deletion or pharmacological inhibition of GCN2 significantly delayed collective cell migration and wound closure. Global transcriptomic, biochemical, and cellular analyses indicated that GCN2 is necessary for maintenance of intracellular free amino acids, particularly cysteine, as well as coordination of RAC1-GTP-driven reactive oxygen species (ROS) generation, lamellipodia formation, and focal adhesion dynamics following keratinocyte wounding. In vivo experiments using mice deficient for GCN2 validated the role of the eIF2 kinase during wound healing in intact skin. These results indicate that GCN2 is critical for appropriate induction of collective cell migration and plays a critical role in coordinating the re-epithelialization of cutaneous wounds.
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Affiliation(s)
- Rebecca R Miles
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Parth H Amin
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Miguel Barriera Diaz
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Jagannath Misra
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Erica Aukerman
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Amitava Das
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Nandini Ghosh
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Tanner Guith
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michael D Knierman
- Laboratory for Experimental Medicine, Eli Lilly and Company, Indianapolis, Indiana, USA
| | - Sashwati Roy
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA; Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Dan F Spandau
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Richard L. Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA.
| | - Ronald C Wek
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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12
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A review of animal models from 2015 to 2020 for preclinical chronic wounds relevant to human health. J Tissue Viability 2021; 30:291-300. [PMID: 34103213 DOI: 10.1016/j.jtv.2021.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/30/2021] [Accepted: 05/26/2021] [Indexed: 01/22/2023]
Abstract
SIGNIFICANCE Chronic wounds fail to heal in a timely manner and exhibit sustained inflammation with slow tissue repair and remodelling. They decrease mobility and quality of life, and remain a major clinical challenge in the long-term care of many patients, affecting 6.5 million individuals annually in the U.S., decreasing mobility and quality of life. Treatment costs are a major burden on the U.S. healthcare system, totalling between $25 and $100 billion annually. Chronic wound severity depends upon several factors such as comorbidities, severity of tissue damage, infection and presence of necrosis and vary greatly in their healing mechanisms. In vivo animal models are critical for studying healing pathways of chronic wounds and seek to replicate clinical factors for trials of topical, systemic, and device-based therapeutics. This comprehensive review discusses murine, rat, lapine, canine, feline and porcine models of chronic wounds. RECENT ADVANCES Foundational chronic wound models for several species are discussed together with refinements and advances in the time period between 2015 and 2020 which have the potential for broad utility in investigating biological and device-based wound treatment therapies for human health. CRITICAL ISSUES Chronic wounds fail to heal in a timely manner and have differing aetiologies, rendering no single in vivo animal model universally applicable. FUTURE DIRECTIONS Further studies are required to develop clinically relevant chronic wound animal model which reflect the clinical reality of the various influences of age, disease, comorbidities and gender on delayed healing and enhance understanding of the biological processes of human wound healing.
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13
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Photobiomodulation therapy was more effective than photobiomodulation plus arginine on accelerating wound healing in an animal model of delayed healing wound. Lasers Med Sci 2021; 37:403-415. [PMID: 33738614 DOI: 10.1007/s10103-021-03271-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 02/10/2021] [Indexed: 10/21/2022]
Abstract
The combined and individual influences of photobiomodulation therapy (PBMT) and arginine on wound strength, stereological parameters, and gene expressions of some related growth factors in ischemic and delayed healing wounds in rats were analyzed. We divided 108 rats into six groups: control, lower energy density (LOW)-PBMT, 2% arginine ointment (Arg 2%), LOW-PBMT + Arg 2%, high energy density (HIGH)-PBMT, and HIGH-PBMT + Arg 2%. First, we generated an ischemic and delayed healing wound model in each rat. We examined wound strength, stereological parameters, and gene expressions of basic fibroblast growth factor (bFGF), vascular endothelial growth factor A (VEGF-A), and stromal cell-derived factor 1 (SDF-1) by quantitative real-time polymerase chain reaction (qRT-PCR). PBMT alone and PBMT + Arg 2% considerably increased wound strength compared to the control and Arg 2% groups during the inflammatory and proliferative steps of wound healing (p < 0.05). In these steps, PBMT alone significantly induced an anti-inflammatory effect and increased fibroblast counts; Arg 2% alone induced an inflammatory response (p < 0.05). Concurrently, PBMT and PBMT + Arg 2% significantly increased keratinocyte counts and volume of the new dermis (p < 0.05). At the remodeling step, the Arg 2% groups had significantly better wound strength than the other groups (p < 0.05). In this step, PBMT and PBMT + Arg 2% significantly decreased inflammation, and increased fibroblast counts, vascular length, and the volume of new epidermis and dermis compared to the control and Arg 2% groups (p < 0.05). In all cases of gene analysis, there were statistically better results in the PBMT and PBMT + Arg 2% groups compared with the Arg 2% and control groups (p < 0.05). The anti-inflammatory and repairing effects of PBMT on an ischemic and delayed healing wound model in rats were shown by significant improvements in wound strength, stereological parameters, and gene expressions of bFGF, VEGF-A, and SDF-1α.
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14
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Methe K, Nayakawde NB, Banerjee D, Sihlbom C, Agbajogu C, Travnikova G, Olausson M. Differential Activation of Immune Cells for Genetically Different Decellularized Cardiac Tissues. Tissue Eng Part A 2020; 26:1180-1198. [DOI: 10.1089/ten.tea.2020.0055] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Ketaki Methe
- Laboratory for Transplantation and Regenerative Medicine, Gothenburg University, Gothenburg, Sweden
| | - Nikhil B. Nayakawde
- Laboratory for Transplantation and Regenerative Medicine, Gothenburg University, Gothenburg, Sweden
| | - Debashish Banerjee
- Laboratory for Transplantation and Regenerative Medicine, Gothenburg University, Gothenburg, Sweden
| | - Carina Sihlbom
- Proteomics Core Facility, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | - Galyna Travnikova
- Laboratory for Transplantation and Regenerative Medicine, Gothenburg University, Gothenburg, Sweden
| | - Michael Olausson
- Laboratory for Transplantation and Regenerative Medicine, Gothenburg University, Gothenburg, Sweden
- Department of Transplantation Surgery at Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden
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15
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Hall PT, Bratcher SZ, Stubbs C, Rifkin RE, Grzeskowiak RM, Burton BJ, Greenacre CB, Stephenson SM, Anderson DE, Crouch DL. Fully Implanted Prostheses for Musculoskeletal Limb Reconstruction After Amputation: An In Vivo Feasibility Study. Ann Biomed Eng 2020; 49:1012-1021. [PMID: 33034786 DOI: 10.1007/s10439-020-02645-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 09/30/2020] [Indexed: 11/28/2022]
Abstract
Previous prostheses for replacing a missing limb following amputation must be worn externally on the body. This limits the extent to which prostheses could physically interface with biological tissues, such as muscles, to enhance functional recovery. The objectives of our study were to (1) test the feasibility of implanting a limb prosthesis, or endoprosthesis, entirely within living skin at the distal end of a residual limb, and (2) identify effective surgical and post-surgical care approaches for implanting endoprostheses in a rabbit model of hindlimb amputation. We iteratively designed, fabricated, and implanted unjointed endoprosthesis prototypes in six New Zealand White rabbits following amputation. In the first three rabbits, the skin failed to heal due to ishemia and dehiscence along the sutured incision. The skin of the final three subsequent rabbits successfully healed over the endoprotheses. Factors that contributed to successful outcomes included modifying the surgical incision to preserve vasculature; increasing the radii size on the endoprostheses to reduce skin stress; collecting radiographs pre-surgery to match the bone pin size to the medullary canal size; and ensuring post-operative bandage integrity. These results will support future work to test jointed endoprostheses that can be attached to muscles.
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Affiliation(s)
- Patrick T Hall
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN, 37966, USA.
| | - Samantha Z Bratcher
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN, 37966, USA
| | - Caleb Stubbs
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN, 37966, USA
| | - Rebecca E Rifkin
- Department of Large Animal Clinical Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA
| | - Remi M Grzeskowiak
- Department of Large Animal Clinical Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA
| | - Bryce J Burton
- Office of Laboratory Animal Care, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA
| | - Cheryl B Greenacre
- Department of Small Animal Clinical Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA
| | | | - David E Anderson
- Department of Large Animal Clinical Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA
| | - Dustin L Crouch
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN, 37966, USA
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16
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Application of stable continuous external electric field promotes wound healing in pig wound model. Bioelectrochemistry 2020; 135:107578. [DOI: 10.1016/j.bioelechem.2020.107578] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/25/2020] [Accepted: 05/31/2020] [Indexed: 12/13/2022]
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17
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Takematsu E, Spencer A, Auster J, Chen PC, Graham A, Martin P, Baker AB. Genome wide analysis of gene expression changes in skin from patients with type 2 diabetes. PLoS One 2020; 15:e0225267. [PMID: 32084158 PMCID: PMC7034863 DOI: 10.1371/journal.pone.0225267] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/31/2019] [Indexed: 12/15/2022] Open
Abstract
Non-healing chronic ulcers are a serious complication of diabetes and are a major healthcare problem. While a host of treatments have been explored to heal or prevent these ulcers from forming, these treatments have not been found to be consistently effective in clinical trials. An understanding of the changes in gene expression in the skin of diabetic patients may provide insight into the processes and mechanisms that precede the formation of non-healing ulcers. In this study, we investigated genome wide changes in gene expression in skin between patients with type 2 diabetes and non-diabetic patients using next generation sequencing. We compared the gene expression in skin samples taken from 27 patients (13 with type 2 diabetes and 14 non-diabetic). This information may be useful in identifying the causal factors and potential therapeutic targets for the prevention and treatment of diabetic related diseases.
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Affiliation(s)
- Eri Takematsu
- University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Adrianne Spencer
- University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Jeff Auster
- University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Po-Chih Chen
- University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Annette Graham
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Scotland, United Kingdom
| | - Patricia Martin
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Scotland, United Kingdom
| | - Aaron B. Baker
- University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX
- The Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX
- Institute for Biomaterials, Drug Delivery and Regenerative Medicine, University of Texas at Austin, Austin, TX
- * E-mail:
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18
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Kim M, Kim SW, Kim H, Hwang CW, Man Choi J, Kang HW. Development of a reproducible in vivo laser-induced scar model for wound healing study and management. BIOMEDICAL OPTICS EXPRESS 2019; 10:1965-1977. [PMID: 31061768 PMCID: PMC6485006 DOI: 10.1364/boe.10.001965] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/14/2019] [Accepted: 03/14/2019] [Indexed: 06/09/2023]
Abstract
The aim of the current study was to establish animal scar models in a simple and rapid manner by comparing three methods. Wounds were created on the buttocks of Sprague Dawley rats. For Group 1, the initial wound was created by surgical incision. For Groups 2 and 3, a 1470-nm laser was employed to generate dermal burns as the initial wound. The wounds in Groups 1 and 3 were then sutured for three days. After the wound healing, Group 2 generated the largest collagen proportion with abundant collagen type I and significant increases in α-SMA and TGF-β1. The proposed method can be an efficient way to develop rat scar models in a simple manner for evaluating scar treatment.
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Affiliation(s)
- Myeongjin Kim
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, South Korea
- The authors (M Kim and SW Kim) equally contributed to this work
| | - Sung Won Kim
- Department of Otolaryngology-Head and Neck Surgery, Kosin University College of Medicine, Busan, South Korea
- The authors (M Kim and SW Kim) equally contributed to this work
| | - Hyejin Kim
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, South Korea
| | - Chi Woo Hwang
- Department of Molecular Biology, Kosin University College of Medicine, Busan, Republic of Korea
| | | | - Hyun Wook Kang
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, South Korea
- Department of Biomedical Engineering and Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, South Korea
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19
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Sami DG, Heiba HH, Abdellatif A. Wound healing models: A systematic review of animal and non-animal models. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.wndm.2018.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Guerra A, Belinha J, Jorge RN. Modelling skin wound healing angiogenesis: A review. J Theor Biol 2018; 459:1-17. [PMID: 30240579 DOI: 10.1016/j.jtbi.2018.09.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 12/22/2022]
Abstract
The occurrence of wounds is a main health concern in Western society due to their high frequency and treatment cost. During wound healing, the formation of a functional blood vessel network through angiogenesis is an essential process. Angiogenesis allows the reestablishment of the normal blood flow, the sufficient exchange of oxygen and nutrients and the removal of metabolic waste, necessary for cell proliferation and viability. Mathematical and computational models provide new tools to improve the healing process. In fact, over the last thirty years, in silico models have been continuously formulated to describe the effect of several biological and mechanical factors in angiogenesis during wound healing. Additionally, with different levels of complexity, these models allow coupling the human skin structure, to distinct cell types and growth factors, to study extracellular matrix composition and to understand its deformation. This paper discusses how in silico models, which are more economical and less time-consuming comparatively to laboratory methodologies, can help test new strategies to promote/optimize angiogenesis. The continuum, cell-based and hybrid mathematical models of wound healing angiogenesis are reviewed in the present paper, in order to identify possible improvements. Accordingly, the development of higher dimension models incorporating multiscale analysis at molecular, cellular and tissue level remains a challenge that future models should consider.
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Affiliation(s)
- Ana Guerra
- INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, Porto 4200-465, Portugal.
| | - Jorge Belinha
- ISEP, School of Engineering, Polytechnic of Porto, Rua Dr. António Bernardino de Almeida, Porto 4200-072, Portugal.
| | - Renato Natal Jorge
- INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, Porto 4200-465, Portugal.
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21
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Pastar I, Wong LL, Egger AN, Tomic-Canic M. Descriptive vs mechanistic scientific approach to study wound healing and its inhibition: Is there a value of translational research involving human subjects? Exp Dermatol 2018; 27:551-562. [PMID: 29660181 PMCID: PMC6374114 DOI: 10.1111/exd.13663] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2018] [Indexed: 12/12/2022]
Abstract
The clinical field of wound healing is challenged by numerous hurdles. Not only are wound-healing disorders complex and multifactorial, but the corresponding patient population is diverse, often elderly and burdened by multiple comorbidities such as diabetes and cardiovascular disease. The care of such patients requires a dedicated, multidisciplinary team of physicians, surgeons, nurses and scientists. In spite of the critical clinical need, it has been over 15 years since a treatment received approval for efficacy by the FDA in the United States. Among the reasons contributing to this lack of effective new treatment modalities is poor understanding of mechanisms that inhibit healing in patients. Additionally, preclinical models do not fully reflect the disease complexity of the human condition, which brings us to a paradox: if we are to use a "mechanistic" approach that favours animal models, we can dissect specific mechanisms using advanced genetic, molecular and cellular technologies, with the caveat that it may not be directly applicable to patients. Traditionally, scientific review panels, for either grant funding or manuscript publication purposes, favour such "mechanistic" approaches whereby human tissue analyses, deemed "descriptive" science, are characterized as a "fishing expedition" and are considered "fatally flawed." However, more emerging evidence supports the notion that the use of human samples provides significant new knowledge regarding the molecular and cellular mechanisms that control wound healing and contribute to inhibition of the process in patients. Here, we discuss the advances, benefits and challenges of translational research in wound healing focusing on human subject research.
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Affiliation(s)
- Irena Pastar
- Wound Healing and Regenerative Medicine Research Program, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School Of Medicine, Miami, FL, USA
| | - Lulu L Wong
- Wound Healing and Regenerative Medicine Research Program, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School Of Medicine, Miami, FL, USA
| | - Andjela N Egger
- Wound Healing and Regenerative Medicine Research Program, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School Of Medicine, Miami, FL, USA
| | - Marjana Tomic-Canic
- Wound Healing and Regenerative Medicine Research Program, Department of Dermatology and Cutaneous Surgery, University of Miami Miller School Of Medicine, Miami, FL, USA
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22
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Singer AJ, Toussaint J, Chung WT, McClain SA, Clark RAF, Asculai E, Geblinger D, Rosenberg L. Development of a contaminated ischemic porcine wound model and the evaluation of bromelain based enzymatic debridement. Burns 2018; 44:896-904. [PMID: 29661553 DOI: 10.1016/j.burns.2017.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 10/17/2022]
Abstract
OBJECTIVES There are no well accepted animal models of chronic wounds, limiting advances in understanding and treatment of chronic ulcers. We developed a porcine wound model which combines multiple factors involved in chronic wounds to create a contaminated necrotic eschar and evaluated the debriding efficacy of a novel bromelain based enzymatic debriding agent (EscharEx). METHODS Contaminated ischemic wounds were created on the flanks of domestic pigs by 'sandwiching' the skin between 2 'O' rings (1 placed on the surface of the skin and the other underneath the skin) for 24h prior to dermatomal excision of the necrotic eschar and its contamination with Staphylococcus aureus and Candida albicans. After confirming the development of infected eschars, additional animals were used to compare the effects of daily application of topical EscharEx or its hydrating vehicle on eschar debridement as a control. RESULTS In all cases, application of the 'O' rings resulted in full thickness necrotic ecshars with invasive infections, which did not reepithelialize and sloughed off spontaneously within 14-21 days. All wounds reepithelialized within 28-42 days forming contracted scars. All EscharEx treated eschars were completely debrided within 7-9 days, while no debridement was evident in eschars treated with the control gel. CONCLUSIONS Our model simulates the initial phase of chronic wounds characterized by a contaminated necrotic eschar allowing evaluation of wound debriding agents, and that a bromelain-based debriding agent completely debrides the contaminated necrotic eschars within one week in this model.
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Affiliation(s)
- Adam J Singer
- Department of Emergency Medicine, Stony Brook University, Stony Brook, NY, United States.
| | - Jimmy Toussaint
- Department of Emergency Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Won Taek Chung
- Department of Emergency Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Steve A McClain
- Department of Emergency Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Richard A F Clark
- Department of Dermatology, Stony Brook University, Stony Brook, NY, United States; Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States
| | | | | | - Lior Rosenberg
- Mediwound Ltd., Yavneh, Israel; Department of Plastic and Reconstructive Surgery, Ben Gurion University, Beer-Sheba, Israel
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23
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Rink C, Wernke MM, Powell HM, Gynawali S, Schroeder RM, Kim JY, Denune JA, Gordillo GM, Colvin JM, Sen CK. Elevated vacuum suspension preserves residual-limb skin health in people with lower-limb amputation: Randomized clinical trial. ACTA ACUST UNITED AC 2018; 53:1121-1132. [PMID: 28355039 DOI: 10.1682/jrrd.2015.07.0145] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 04/13/2016] [Indexed: 11/05/2022]
Abstract
A growing number of clinical trials and case reports support qualitative claims that use of an elevated vacuum suspension (EVS) prosthesis improves residual-limb health on the basis of self-reported questionnaires, clinical outcomes scales, and wound closure studies. Here, we report first efforts to quantitatively assess residual-limb circulation in response to EVS. Residual-limb skin health and perfusion of people with lower-limb amputation (N = 10) were assessed during a randomized crossover study comparing EVS with nonelevated vacuum suspension (control) over a 32 wk period using noninvasive probes (transepidermal water loss, laser speckle imaging, transcutaneous oxygen measurement) and functional hyperspectral imaging approaches. Regardless of the suspension system, prosthesis donning decreased perfusion in the residual limb under resting conditions. After 16 wk of use, EVS improved residual-limb oxygenation during treadmill walking. Likewise, prosthesis-induced reactive hyperemia was attenuated with EVS following 16 wk of use. Skin barrier function was preserved with EVS but disrupted after control socket use. Taken together, outcomes suggest chronic EVS use improves perfusion and preserves skin barrier function in people with lower-limb amputation. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov; "Evaluation of limb health associated with a prosthetic vacuum socket system": NCT01839123; https://clinicaltrials.gov/ct2/show/NCT01839123?term=NCT01839123&rank=1.
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Affiliation(s)
- Cameron Rink
- Department of Surgery, Comprehensive Wound Center, and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH
| | | | - Heather M Powell
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH
| | - Surya Gynawali
- Department of Surgery, Comprehensive Wound Center, and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH
| | | | - Jayne Y Kim
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH
| | | | - Gayle M Gordillo
- Department of Surgery, Comprehensive Wound Center, and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH.,Department of Plastic Surgery, The Ohio State University Wexner Medical Center, Columbus, OH
| | | | - Chandan K Sen
- Department of Surgery, Comprehensive Wound Center, and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH
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24
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Development and Characterisation of a Human Chronic Skin Wound Cell Line-Towards an Alternative for Animal Experimentation. Int J Mol Sci 2018; 19:ijms19041001. [PMID: 29584680 PMCID: PMC5979489 DOI: 10.3390/ijms19041001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 12/30/2022] Open
Abstract
Background: Chronic skin wounds are a growing financial burden for healthcare providers, causing discomfort/immobility to patients. Whilst animal chronic wound models have been developed to allow for mechanistic studies and to develop/test potential therapies, such systems are not good representations of the human chronic wound state. As an alternative, human chronic wound fibroblasts (CWFs) have permitted an insight into the dysfunctional cellular mechanisms that are associated with these wounds. However, such cells strains have a limited replicative lifespan and therefore a limited reproducibility/usefulness. Objectives: To develop/characterise immortalised cell lines of CWF and patient-matched normal fibroblasts (NFs). Methods and Results: Immortalisation with human telomerase resulted in both CWF and NF proliferating well beyond their replicative senescence end-point (respective cell strains senesced as normal). Gene expression analysis demonstrated that, whilst proliferation-associated genes were up-regulated in the cell lines (as would be expected), the immortalisation process did not significantly affect the disease-specific genotype. Immortalised CWF (as compared to NF) also retained a distinct impairment in their wound repopulation potential (in line with CWF cell strains). Conclusions: These novel CWF cell lines are a credible animal alternative and could be a valuable research tool for understanding both the aetiology of chronic skin wounds and for therapeutic pre-screening.
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25
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Ray VA, Hill PJ, Stover CK, Roy S, Sen CK, Yu L, Wozniak DJ, DiGiandomenico A. Anti-Psl Targeting of Pseudomonas aeruginosa Biofilms for Neutrophil-Mediated Disruption. Sci Rep 2017; 7:16065. [PMID: 29167572 PMCID: PMC5700069 DOI: 10.1038/s41598-017-16215-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/08/2017] [Indexed: 01/05/2023] Open
Abstract
Bacterial biofilms are recalcitrant to antibiotic therapy and a major cause of persistent and recurrent infections. New antibody-based therapies may offer potential to target biofilm specific components for host-cell mediated bacterial clearance. For Pseudomonas aeruginosa, human monoclonal antibodies (mAbs) targeting the Psl biofilm exopolysaccharide exhibit protective activity against planktonic bacteria in acute infection models. However, anti-Psl mAb activity against P. aeruginosa biofilms is unknown. Here, we demonstrate that anti-Psl mAbs targeting three distinct Psl epitopes exhibit stratified binding in mature in vitro biofilms and bind Psl within the context of a chronic biofilm infection. These mAbs also exhibit differential abilities to inhibit early biofilm events and reduce biomass from mature biofilms in the presence of neutrophils. Importantly, a mAb mixture with neutrophils exhibited the greatest biomass reduction, which was further enhanced when combined with meropenem, a common anti-Pseudomonal carbapenem antibiotic. Moreover, neutrophil-mediated killing of biofilm bacteria correlated with the evident mAb epitope stratification within the biofilm. Overall, our results suggest that anti-Psl mAbs might be promising candidates for adjunctive use with antibiotics to inhibit/disrupt P. aeruginosa biofilms as a result of chronic infection.
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Affiliation(s)
- Valerie A Ray
- Center for Microbial Interface Biology, Departments of Microbial Infection and Immunity, Microbiology, Ohio State University, Columbus, OH, 43210, USA
| | - Preston J Hill
- Center for Microbial Interface Biology, Departments of Microbial Infection and Immunity, Microbiology, Ohio State University, Columbus, OH, 43210, USA
| | - C Kendall Stover
- Department of Infectious Diseases, MedImmune, LLC, Gaithersburg, MD, 20878, USA
| | - Sashwati Roy
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell Based Therapies, Ohio State University Medical Center, Columbus, OH, 43210, USA.,Department of Surgery, College of Veterinary Medicine, Ohio State University, Columbus, OH, 43210, USA
| | - Chandan K Sen
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell Based Therapies, Ohio State University Medical Center, Columbus, OH, 43210, USA.,Department of Surgery, College of Veterinary Medicine, Ohio State University, Columbus, OH, 43210, USA
| | - Li Yu
- Translational Sciences, MedImmune, LLC, Gaithersburg, MD, 20878, USA
| | - Daniel J Wozniak
- Center for Microbial Interface Biology, Departments of Microbial Infection and Immunity, Microbiology, Ohio State University, Columbus, OH, 43210, USA
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26
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Patil P, Martin JR, Sarett SM, Pollins AC, Cardwell NL, Davidson JM, Guelcher SA, Nanney LB, Duvall CL. Porcine Ischemic Wound-Healing Model for Preclinical Testing of Degradable Biomaterials. Tissue Eng Part C Methods 2017; 23:754-762. [PMID: 28762881 DOI: 10.1089/ten.tec.2017.0202] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Impaired wound healing that mimics chronic human skin pathologies is difficult to achieve in current animal models, hindering testing and development of new therapeutic biomaterials that promote wound healing. In this article, we describe a refinement and simplification of the porcine ischemic wound model that increases the size and number of experimental sites per animal. By comparing three flap geometries, we adopted a superior configuration (15 × 10 cm) that enabled testing of twenty 1 cm2 wounds in each animal: 8 total ischemic wounds within 4 bipedicle flaps and 12 nonischemic wounds. The ischemic wounds exhibited impaired skin perfusion for ∼1 week. To demonstrate the utility of the model for comparative testing of tissue regenerative biomaterials, we evaluated the healing process in wounds implanted with highly porous poly (thioketal) urethane (PTK-UR) scaffolds that were fabricated through reaction of reactive oxygen species (ROS)-cleavable PTK macrodiols with isocyanates. PTK-lysine triisocyanate (LTI) scaffolds degraded significantly in vitro under both oxidative and hydrolytic conditions whereas PTK-hexamethylene diisocyanate trimer (HDIt) scaffolds were resistant to hydrolytic breakdown and degraded exclusively through an ROS-dependent mechanism. Upon placement into porcine wounds, both types of PTK-UR materials fostered new tissue ingrowth over 10 days in both ischemic and nonischemic tissue. However, wound perfusion, tissue infiltration and the abundance of pro-regenerative, M2-polarized macrophages were markedly lower in ischemic wounds independent of scaffold type. The PTK-LTI implants significantly improved tissue infiltration and perfusion compared with analogous PTK-HDIt scaffolds in ischemic wounds. Both LTI and HDIt-based PTK-UR implants enhanced M2 macrophage activity, and these cells were selectively localized at the scaffold/tissue interface. In sum, this modified porcine wound-healing model decreased animal usage, simplified procedures, and permitted a more robust evaluation of tissue engineering materials in preclinical wound healing research. Deployment of the model for a relevant biomaterial comparison yielded results that support the use of the PTK-LTI over the PTK-HDIt scaffold formulation for future advanced therapeutic studies.
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Affiliation(s)
- Prarthana Patil
- 1 Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee
| | - John R Martin
- 1 Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee
| | - Samantha M Sarett
- 1 Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee
| | - Alonda C Pollins
- 2 Department of Plastic Surgery, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Nancy L Cardwell
- 2 Department of Plastic Surgery, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Jeffrey M Davidson
- 3 Department of Pathology Microbiology and Immunology, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Scott A Guelcher
- 1 Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee.,4 Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee.,5 Department of Medicine and Division of Clinical Pharmacology, Vanderbilt Center for Bone Biology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Lillian B Nanney
- 2 Department of Plastic Surgery, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Craig L Duvall
- 1 Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee
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27
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Rink CL, Wernke MM, Powell HM, Tornero M, Gnyawali SC, Schroeder RM, Kim JY, Denune JA, Albury AW, Gordillo GM, Colvin JM, Sen CK. Standardized Approach to Quantitatively Measure Residual Limb Skin Health in Individuals with Lower Limb Amputation. Adv Wound Care (New Rochelle) 2017; 6:225-232. [PMID: 28736682 DOI: 10.1089/wound.2017.0737] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 05/01/2017] [Indexed: 12/29/2022] Open
Abstract
Objective: (1) Develop a standardized approach to quantitatively measure residual limb skin health. (2) Report reference residual limb skin health values in people with transtibial and transfemoral amputation. Approach: Residual limb health outcomes in individuals with transtibial (n = 5) and transfemoral (n = 5) amputation were compared to able-limb controls (n = 4) using noninvasive imaging (hyperspectral imaging and laser speckle flowmetry) and probe-based approaches (laser doppler flowmetry, transcutaneous oxygen, transepidermal water loss, surface electrical capacitance). Results: A standardized methodology that employs noninvasive imaging and probe-based approaches to measure residual limb skin health are described. Compared to able-limb controls, individuals with transtibial and transfemoral amputation have significantly lower transcutaneous oxygen tension, higher transepidermal water loss, and higher surface electrical capacitance in the residual limb. Innovation: Residual limb health as a critical component of prosthesis rehabilitation for individuals with lower limb amputation is understudied in part due to a lack of clinical measures. Here, we present a standardized approach to measure residual limb health in people with transtibial and transfemoral amputation. Conclusion: Technology advances in noninvasive imaging and probe-based measures are leveraged to develop a standardized approach to quantitatively measure residual limb health in individuals with lower limb loss. Compared to able-limb controls, resting residual limb physiology in people that have had transfemoral or transtibial amputation is characterized by lower transcutaneous oxygen tension and poorer skin barrier function.
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Affiliation(s)
- Cameron L. Rink
- Department of Surgery, Comprehensive Wound Center and Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | | | - Heather M. Powell
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio
| | - Mark Tornero
- Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Surya C. Gnyawali
- Department of Surgery, Comprehensive Wound Center and Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | | | - Jayne Y. Kim
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio
| | | | | | - Gayle M. Gordillo
- Department of Plastic Surgery, Comprehensive Wound Center and Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | | | - Chandan K. Sen
- Department of Surgery, Comprehensive Wound Center and Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
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28
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McQuilling JP, Vines JB, Mowry KC. In vitro assessment of a novel, hypothermically stored amniotic membrane for use in a chronic wound environment. Int Wound J 2017; 14:993-1005. [PMID: 28370981 PMCID: PMC7949938 DOI: 10.1111/iwj.12748] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/03/2017] [Accepted: 03/04/2017] [Indexed: 12/18/2022] Open
Abstract
Chronic wounds require extensive healing time and place patients at risk of infection and amputation. Recently, a fresh hypothermically stored amniotic membrane (HSAM) was developed and has subsequently shown promise in its ability to effectively heal chronic wounds. The purpose of this study is to investigate the mechanisms of action that contribute to wound-healing responses observed with HSAM. A proteomic analysis was conducted on HSAM, measuring 25 growth factors specific to wound healing within the grafts. The rate of release of these cytokines from HSAMs was also measured. To model the effect of these cytokines and their role in wound healing, proliferation and migration assays with human fibroblasts and keratinocytes were conducted, along with tube formation assays measuring angiogenesis using media conditioned from HSAM. Additionally, the cell-matrix interactions between fibroblasts and HSAM were investigated. Conditioned media from HSAM significantly increased both fibroblast and keratinocyte proliferation and migration and induced more robust tube formation in angiogenesis assays. Fibroblasts cultured on HSAMs were found to migrate into and deposit matrix molecules within the HSAM graft. These collective results suggest that HSAM positively affects various critical pathways in chronic wound healing, lending further support to promising qualitative results seen clinically and providing further validation for ongoing clinical trials.
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Affiliation(s)
| | - Jeremy B Vines
- Research and Development, NuTech Medical, Birmingham, AL, USA
| | - Katie C Mowry
- Research and Development, NuTech Medical, Birmingham, AL, USA
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29
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Das A, Datta S, Rhea B, Sinha M, Veeraragavan M, Gordillo G, Roy S. The Human Skeletal Muscle Transcriptome in Response to Oral Shilajit Supplementation. J Med Food 2017; 19:701-9. [PMID: 27414521 DOI: 10.1089/jmf.2016.0010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED The objective of the present study ( clinicaltrials.gov NCT02026414) was to observe the effects of oral supplementation of a purified and standardized Shilajit extract on skeletal muscle adaptation in adult overweight/class I obese human subjects from the U.S. POPULATION Shilajit is a mineral pitch that oozes out of Himalayan rocks. The study design consisted of a baseline visit, followed by 8 weeks of 250 mg of oral Shilajit supplementation b.i.d., and additional 4 weeks of supplementation with exercise. At each visit, blood samples and muscle biopsies were collected for further analysis. Supplementation was well tolerated without any changes in blood glucose levels and lipid profile after 8 weeks of oral supplementation and the additional 4 weeks of oral supplementation with exercise. In addition, no changes were noted in creatine kinase and serum myoglobin levels after 8 weeks of oral supplementation and the additional 4 weeks of supplementation with exercise. Microarray analysis identified a cluster of 17 extracellular matrix (ECM)-related probe sets that were significantly upregulated in muscles following 8 weeks of oral supplementation compared with the expression at the baseline visit. This cluster included tenascin XB, decorin, myoferlin, collagen, elastin, fibrillin 1, and fibronectin 1. The differential expression of these genes was confirmed using quantitative real-time polymerase chain reaction (RT-PCR). The study provided maiden evidence that oral Shilajit supplementation in adult overweight/class I obese human subjects promoted skeletal muscle adaptation through upregulation of ECM-related genes that control muscle mechanotransduction properties, elasticity, repair, and regeneration.
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Affiliation(s)
- Amitava Das
- 1 Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell-Based Therapies and Comprehensive Wound Center, The Ohio State University , Wexner Medical Center, Columbus, Ohio, USA
| | - Soma Datta
- 1 Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell-Based Therapies and Comprehensive Wound Center, The Ohio State University , Wexner Medical Center, Columbus, Ohio, USA
| | - Brian Rhea
- 1 Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell-Based Therapies and Comprehensive Wound Center, The Ohio State University , Wexner Medical Center, Columbus, Ohio, USA
| | - Mithun Sinha
- 1 Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell-Based Therapies and Comprehensive Wound Center, The Ohio State University , Wexner Medical Center, Columbus, Ohio, USA
| | | | - Gayle Gordillo
- 3 Department of Plastic Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell-Based Therapies and Comprehensive Wound Center, The Ohio State University , Wexner Medical Center, Columbus, Ohio, USA
| | - Sashwati Roy
- 1 Department of Surgery, Davis Heart and Lung Research Institute, Center for Regenerative Medicine and Cell-Based Therapies and Comprehensive Wound Center, The Ohio State University , Wexner Medical Center, Columbus, Ohio, USA
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30
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André-Lévigne D, Modarressi A, Pignel R, Bochaton-Piallat ML, Pittet-Cuénod B. Hyperbaric oxygen therapy promotes wound repair in ischemic and hyperglycemic conditions, increasing tissue perfusion and collagen deposition. Wound Repair Regen 2016; 24:954-965. [PMID: 27684570 DOI: 10.1111/wrr.12480] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/03/2016] [Indexed: 01/21/2023]
Abstract
The treatment of chronic wounds remains inconsistent and empirical. Hyperbaric oxygen therapy (HBOT) is a promising method to improve wound repair but there is still a lack of understanding of its mechanisms of action and its indications are not yet clearly defined. We studied the effects of HBOT in four different wound conditions by inflicting bilateral wounds on the dorsal aspect of the feet of nonischemic or ischemic limbs in normoglycemic or hyperglycemic rats. To create an ischemic condition, arterial resection was performed unilaterally. Forty-four animals received HBOT five times a week until complete wound closure. Wound repair was compared with 44 rats receiving standard dressing only. HBOT increased blood flow and accelerated wound closure in ischemic and hyperglycemic wounds, most significantly when the two conditions were combined. Wound contraction and reepithelialization were similarly stimulated by HBOT. The acceleration of wound contraction was not associated with increased myofibroblasts expression, nor fibroblast recruitment or higher cell count in the granulation tissue. Of note, we observed a significant increase in collagen deposition in early time points in ischemic wounds receiving HBOT. This data emphasizes that an early application of HBOT might be crucial to its efficacy. We concluded that wounds where ischemia and hyperglycemia are combined, as it is often the case in diabetic patients, have the best chance to benefit from HBOT.
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Affiliation(s)
- Dominik André-Lévigne
- Division of Plastic, Reconstructive & Aesthetic Surgery, Faculty of Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Ali Modarressi
- Division of Plastic, Reconstructive & Aesthetic Surgery, Faculty of Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Rodrigue Pignel
- Division of Hyperbaric Medicine, Department of Health and Community Medicine, University Hospitals of Geneva, Geneva, Switzerland'
| | | | - Brigitte Pittet-Cuénod
- Division of Plastic, Reconstructive & Aesthetic Surgery, Faculty of Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
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31
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Primary Pancreatic Secretinoma: Further Evidence Supporting Secretin as a Diarrheogenic Hormone. Ann Surg 2016; 266:346-352. [PMID: 27501174 DOI: 10.1097/sla.0000000000001938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To document the existence of primary pancreatic secretinoma in patients with watery diarrhea syndrome (WDS) and achlorhydria and establish secretin as a diarrheogenic hormone. BACKGROUND Vasoactive intestinal peptide (VIP) has been widely accepted as the main mediator of WDS. However, in 1968, Zollinger et al reported 2 female patients with pancreatic neuroendocrine tumors, WDS, and achlorhydria. During surgery on the first, a 24-year-old patient, they noticed distended duodenum filled with fluid and a dilated gallbladder containing dilute bile with high bicarbonate concentration. After excision of the tumor, WDS ceased and gastric acid secretion returned. The second, a 47-year-old, patient's metastatic tumor extract given intravenously in dogs, produced significantly increased pancreatic and biliary fluid rich in bicarbonate. They suggested a secretin-like hormone of islet cell origin explains WDS and achlorhydria. These observations, however, predated radioimmunoassay, immunohistochemical staining, and other molecular studies. METHODS The first patient's tumor tissue was investigated for secretin and VIP. Using both immunohistochemistry and laser microdissection and pressure catapulting technique for RNA isolation and subsequent reverse transcription polymerase chain reaction, the expression levels of secretin, and VIP were measured. RESULTS Immunoreactive secretin and its mRNA were predominantly found in the tumor tissue whereas VIP and its mRNA were scarce. CONCLUSIONS The findings strongly support that the WDS and achlorhydria in this patient may have been caused by secretin as originally proposed in 1968 and that secretin may act as a diarrheogenic hormone.
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32
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Javierre E. Impact of anomalous transport kinetics on the progress of wound healing. Med Eng Phys 2016; 38:885-94. [PMID: 27461569 DOI: 10.1016/j.medengphy.2016.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 02/12/2016] [Accepted: 04/03/2016] [Indexed: 11/15/2022]
Abstract
This work focuses on the transport kinetics of chemical and cellular species during wound healing. Anomalous transport kinetics, coupling sub- and superdiffusion with chemotaxis, and fractional viscoelasticity of soft tissues are analyzed from a modeling point of view. The paper presents a generalization of well stablished mechano-chemical models of wound contraction (Murphy et al., 2012; Valero et al., 2014) to include the previously mentioned anomalous effects by means of partial differential equations of fractional order. Results show the effect that anomalous dynamics have on the contraction rate and extension and on the distribution of biological species, and indicators of fibroproliferative disorders are identified.
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Affiliation(s)
- E Javierre
- Centro Universitario de la Defensa, Academia General Militar, Ctra. Huesca s/n. 50090 Zaragoza, Spain.
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33
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Magin CM, Neale DB, Drinker MC, Willenberg BJ, Reddy ST, La Perle KM, Schultz GS, Brennan AB. Evaluation of a bilayered, micropatterned hydrogel dressing for full-thickness wound healing. Exp Biol Med (Maywood) 2016; 241:986-95. [PMID: 27037279 DOI: 10.1177/1535370216640943] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nearly 12 million wounds are treated in emergency departments throughout the United States every year. The limitations of current treatments for complex, full-thickness wounds are the driving force for the development of new wound treatment devices that result in faster healing of both dermal and epidermal tissue. Here, a bilayered, biodegradable hydrogel dressing that uses microarchitecture to guide two key steps in the proliferative phase of wound healing, re-epithelialization, and revascularization, was evaluated in vitro in a cell migration assay and in vivo in a bipedicle ischemic rat wound model. Results indicate that the Sharklet™-micropatterned apical layer of the dressing increased artificial wound coverage by up to 64%, P = 0.024 in vitro. In vivo evaluation demonstrated that the bilayered dressing construction enhanced overall healing outcomes significantly compared to untreated wounds and that these outcomes were not significantly different from a leading clinically available wound dressing. Collectively, these results demonstrate high potential for this new dressing to effectively accelerate wound healing.
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Affiliation(s)
| | - Dylan B Neale
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA
| | | | - Bradley J Willenberg
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA Department of Internal Medicine, University of Central Florida, Orlando, FL 32827, USA Saisijin Biotech, LLC, Orlando, FL 32827, USA
| | | | - Krista Md La Perle
- Department of Veterinary Biosciences, College of Veterinary Medicine and Comparative Pathology & Mouse Phenotyping Shared Resource, Comprehensive Cancer Center The Ohio State University, Columbus, OH 43210, USA
| | - Gregory S Schultz
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Anthony B Brennan
- Sharklet Technologies, Inc., Aurora, CO 80045, USA Saisijin Biotech, LLC, Orlando, FL 32827, USA J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA
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Yang P, Pei Q, Yu T, Chang Q, Wang D, Gao M, Zhang X, Liu Y. Compromised Wound Healing in Ischemic Type 2 Diabetic Rats. PLoS One 2016; 11:e0152068. [PMID: 27028201 PMCID: PMC4814123 DOI: 10.1371/journal.pone.0152068] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/07/2016] [Indexed: 02/06/2023] Open
Abstract
Ischemia is one of the main epidemic factors and characteristics of diabetic chronic wounds, and exerts a profound effect on wound healing. To explore the mechanism of and the cure for diabetic impaired wound healing, we established a type 2 diabetic rat model. We used an 8weeks high fat diet (HFD) feeding regimen followed by multiple injections of streptozotocin (STZ) at a dose of 10mg/kg to induce Wister rat to develop type 2 diabetes. Metabolic characteristics were assessed at the 5th week after the STZ injections to confirm the establishment of diabetes mellitus on the rodent model. A bipedicle flap, with length to width ratio 1.5, was performed on the back of the rat to make the flap area ischemic. Closure of excisional wounds on this bipedicle flap and related physiological and pathological changes were studied using histological, immunohistochemical, real time PCR and protein immunoblot approaches. Our results demonstrated that a combination of HFD feeding and a low dose of STZ is capable of inducing the rats to develop type 2 diabetes with noticeable insulin resistance, persistent hyperglycemia, moderate degree of insulinemia, as well as high serum cholesterol and high triglyceride levels. The excision wounds on the ischemic double pedicle flap showed deteriorative healing features comparing with non-ischemic diabetic wounds, including: delayed healing, exorbitant wound inflammatory response, excessive and prolonged ROS production and excessive production of MMPs. Our study suggested that HFD feeding combined with STZ injection could induce type 2 diabetes in rat. Our ischemic diabetic wound model is suitable for the investigation of human diabetic related wound repair; especically for diabetic chronic wounds.
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Affiliation(s)
- Peilang Yang
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Qing Pei
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Tianyi Yu
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Qingxuan Chang
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Di Wang
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Min Gao
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Xiong Zhang
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
| | - Yan Liu
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, Shanghai 200025, China
- * E-mail:
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Nagaraja S, Reifman J, Mitrophanov AY. Computational Identification of Mechanistic Factors That Determine the Timing and Intensity of the Inflammatory Response. PLoS Comput Biol 2015; 11:e1004460. [PMID: 26633296 PMCID: PMC4669096 DOI: 10.1371/journal.pcbi.1004460] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 06/16/2015] [Indexed: 11/19/2022] Open
Abstract
Timely resolution of inflammation is critical for the restoration of homeostasis in injured or infected tissue. Chronic inflammation is often characterized by a persistent increase in the concentrations of inflammatory cells and molecular mediators, whose distinct amount and timing characteristics offer an opportunity to identify effective therapeutic regulatory targets. Here, we used our recently developed computational model of local inflammation to identify potential targets for molecular interventions and to investigate the effects of individual and combined inhibition of such targets. This was accomplished via the development and application of computational strategies involving the simulation and analysis of thousands of inflammatory scenarios. We found that modulation of macrophage influx and efflux is an effective potential strategy to regulate the amount of inflammatory cells and molecular mediators in both normal and chronic inflammatory scenarios. We identified three molecular mediators − tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and the chemokine CXCL8 − as potential molecular targets whose individual or combined inhibition may robustly regulate both the amount and timing properties of the kinetic trajectories for neutrophils and macrophages in chronic inflammation. Modulation of macrophage flux, as well as of the abundance of TNF-α, TGF-β, and CXCL8, may improve the resolution of chronic inflammation. A recent approach to quantitatively characterize the timing and intensity of the inflammatory response relies on the use of four quantities termed inflammation indices. The values of the inflammation indices may reflect the differences between normal and pathological inflammation, and may be used to gauge the effects of therapeutic interventions aimed to control inflammation. Yet, the specific inflammatory mechanisms that can be targeted to selectively control these indices remain unknown. Here, we developed and applied a computational strategy to identify potential target mechanisms to regulate such indices. We used our recently developed model of local inflammation to simulate thousands of inflammatory scenarios. We then subjected the corresponding inflammation index values to sensitivity and correlation analysis. We found that the inflammation indices may be significantly influenced by the macrophage influx and efflux rates, as well as by the degradation rates of three specific molecular mediators. These results suggested that the indices can be effectively regulated by individual or combined inhibition of those molecular mediators, which we confirmed by computational experiments. Taken together, our results highlight possible targets of therapeutic intervention that can be used to control both the timing and the intensity of the inflammatory response.
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Affiliation(s)
- Sridevi Nagaraja
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
- * E-mail:
| | - Alexander Y. Mitrophanov
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
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Flegg JA, Menon SN, Maini PK, McElwain DLS. On the mathematical modeling of wound healing angiogenesis in skin as a reaction-transport process. Front Physiol 2015; 6:262. [PMID: 26483695 PMCID: PMC4588694 DOI: 10.3389/fphys.2015.00262] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/04/2015] [Indexed: 11/13/2022] Open
Abstract
Over the last 30 years, numerous research groups have attempted to provide mathematical descriptions of the skin wound healing process. The development of theoretical models of the interlinked processes that underlie the healing mechanism has yielded considerable insight into aspects of this critical phenomenon that remain difficult to investigate empirically. In particular, the mathematical modeling of angiogenesis, i.e., capillary sprout growth, has offered new paradigms for the understanding of this highly complex and crucial step in the healing pathway. With the recent advances in imaging and cell tracking, the time is now ripe for an appraisal of the utility and importance of mathematical modeling in wound healing angiogenesis research. The purpose of this review is to pedagogically elucidate the conceptual principles that have underpinned the development of mathematical descriptions of wound healing angiogenesis, specifically those that have utilized a continuum reaction-transport framework, and highlight the contribution that such models have made toward the advancement of research in this field. We aim to draw attention to the common assumptions made when developing models of this nature, thereby bringing into focus the advantages and limitations of this approach. A deeper integration of mathematical modeling techniques into the practice of wound healing angiogenesis research promises new perspectives for advancing our knowledge in this area. To this end we detail several open problems related to the understanding of wound healing angiogenesis, and outline how these issues could be addressed through closer cross-disciplinary collaboration.
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Affiliation(s)
- Jennifer A Flegg
- School of Mathematical Sciences, Monash University Melbourne, VIC, Australia
| | | | - Philip K Maini
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford Oxford, UK
| | - D L Sean McElwain
- Institute of Health and Biomedical Innovation and School of Mathematical Sciences, Queensland University of Technology Brisbane, QLD, Australia
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Parton A, McGilligan V, O’Kane M, Baldrick FR, Watterson S. Computational modelling of atherosclerosis. Brief Bioinform 2015; 17:562-75. [DOI: 10.1093/bib/bbv081] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Indexed: 12/24/2022] Open
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Friedman A. Free boundary problems in biology. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0368. [PMID: 26261370 DOI: 10.1098/rsta.2014.0368] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/23/2014] [Indexed: 06/04/2023]
Abstract
In this paper, I review several free boundary problems that arise in the mathematical modelling of biological processes. The biological topics are quite diverse: cancer, wound healing, biofilms, granulomas and atherosclerosis. For each of these topics, I describe the biological background and the mathematical model, and then proceed to state mathematical results, including existence and uniqueness theorems, stability and asymptotic limits, and the behaviour of the free boundary. I also suggest, for each of the topics, open mathematical problems.
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Affiliation(s)
- Avner Friedman
- Department of Mathematics, The Ohio State University, Columbus, OH 43210, USA
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Nunan R, Harding KG, Martin P. Clinical challenges of chronic wounds: searching for an optimal animal model to recapitulate their complexity. Dis Model Mech 2015; 7:1205-13. [PMID: 25359790 PMCID: PMC4213725 DOI: 10.1242/dmm.016782] [Citation(s) in RCA: 290] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The efficient healing of a skin wound is something that most of us take for granted but is essential for surviving day-to-day knocks and cuts, and is absolutely relied on clinically whenever a patient receives surgical intervention. However, the management of a chronic wound – defined as a barrier defect that has not healed in 3 months – has become a major therapeutic challenge throughout the Western world, and it is a problem that will only escalate with the increasing incidence of conditions that impede wound healing, such as diabetes, obesity and vascular disorders. Despite being clinically and molecularly heterogeneous, all chronic wounds are generally assigned to one of three major clinical categories: leg ulcers, diabetic foot ulcers or pressure ulcers. Although we have gleaned much knowledge about the fundamental cellular and molecular mechanisms that underpin healthy, acute wound healing from various animal models, we have learned much less about chronic wound repair pathology from these models. This might largely be because the animal models being used in this field of research have failed to recapitulate the clinical features of chronic wounds. In this Clinical Puzzle article, we discuss the clinical complexity of chronic wounds and describe the best currently available models for investigating chronic wound pathology. We also assess how such models could be optimised to become more useful tools for uncovering pathological mechanisms and potential therapeutic treatments.
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Affiliation(s)
- Robert Nunan
- Schools of Biochemistry and Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK.
| | - Keith G Harding
- School of Medicine, University of Cardiff, Cardiff, CF14 4XN, UK
| | - Paul Martin
- Schools of Biochemistry and Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK. School of Medicine, University of Cardiff, Cardiff, CF14 4XN, UK
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Soto RJ, Schoenfisch MH. Preclinical Performance Evaluation of Percutaneous Glucose Biosensors: Experimental Considerations and Recommendations. J Diabetes Sci Technol 2015; 9:978-84. [PMID: 26085566 PMCID: PMC4667323 DOI: 10.1177/1932296815590628] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The utility of continuous glucose monitoring devices remains limited by an obstinate foreign body response (FBR) that degrades the analytical performance of the in vivo sensor. A number of novel materials that resist or delay the FBR have been proposed as outer, tissue-contacting glucose sensor membranes as a strategy to improve sensor accuracy. Traditionally, researchers have examined the ability of a material to minimize the host response by assessing adsorbed cell morphology and tissue histology. However, these techniques do not adequately predict in vivo glucose sensor function, necessitating sensor performance evaluation in a relevant animal model prior to human testing. Herein, the effects of critical experimental parameters, including the animal model and data processing methods, on the reliability and usefulness of preclinical sensor performance data are considered.
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Affiliation(s)
- Robert J Soto
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Mark H Schoenfisch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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41
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42
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Trujillo AN, Kesl SL, Sherwood J, Wu M, Gould LJ. Demonstration of the rat ischemic skin wound model. J Vis Exp 2015:e52637. [PMID: 25866964 PMCID: PMC4401402 DOI: 10.3791/52637] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The propensity for chronic wounds in humans increases with ageing, disease conditions such as diabetes and impaired cardiovascular function, and unrelieved pressure due to immobility. Animal models have been developed that attempt to mimic these conditions for the purpose of furthering our understanding of the complexity of chronic wounds. The model described herein is a rat ischemic skin flap model that permits a prolonged reduction of blood flow resulting in wounds that become ischemic and resemble a chronic wound phenotype (reduced vascularization, increased inflammation and delayed wound closure). It consists of a bipedicled dorsal flap with 2 ischemic wounds placed centrally and 2 non-ischemic wounds lateral to the flap as controls. A novel addition to this ischemic skin flap model is the placement of a silicone sheet beneath the flap that functions as a barrier and a splint to prevent revascularization and reduce contraction as the wounds heal. Despite the debate of using rats for wound healing studies due to their quite distinct anatomic and physiologic differences compared to humans (i.e., the presence of a panniculus carnosus muscle, short life-span, increased number of hair follicles, and their ability to heal infected wounds) the modifications employed in this model make it a valuable alternative to previously developed ischemic skin flap models.
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Affiliation(s)
- Andrea N Trujillo
- Department of Molecular Pharmacology and Physiology, University of South Florida
| | - Shannon L Kesl
- Department of Molecular Pharmacology and Physiology, University of South Florida; Department of Surgery, University of South Florida
| | - Jacob Sherwood
- Department of Molecular Pharmacology and Physiology, University of South Florida
| | - Mack Wu
- Department of Surgery, University of South Florida
| | - Lisa J Gould
- Department of Molecular Pharmacology and Physiology, University of South Florida; Wound Recovery and Hyperbaric Medicine Center, Kent Memorial Hospital;
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Gnyawali SC, Barki KG, Mathew-Steiner SS, Dixith S, Vanzant D, Kim J, Dickerson JL, Datta S, Powell H, Roy S, Bergdall V, Sen CK. High-resolution harmonics ultrasound imaging for non-invasive characterization of wound healing in a pre-clinical swine model. PLoS One 2015; 10:e0122327. [PMID: 25799513 PMCID: PMC4370665 DOI: 10.1371/journal.pone.0122327] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 02/10/2015] [Indexed: 11/18/2022] Open
Abstract
This work represents the first study employing non-invasive high-resolution harmonic ultrasound imaging to longitudinally characterize skin wound healing. Burn wounds (day 0-42), on the dorsum of a domestic Yorkshire white pig were studied non-invasively using tandem digital planimetry, laser speckle imaging and dual mode (B and Doppler) ultrasound imaging. Wound depth, as measured by B-mode imaging, progressively increased until day 21 and decreased thereafter. Initially, blood flow at the wound edge increased up to day 14 and subsequently regressed to baseline levels by day 21, when the wound was more than 90% closed. Coinciding with regression of blood flow at the wound edge, there was an increase in blood flow in the wound bed. This was observed to regress by day 42. Such changes in wound angiogenesis were corroborated histologically. Gated Doppler imaging quantitated the pulse pressure of the primary feeder artery supplying the wound site. This pulse pressure markedly increased with a bimodal pattern following wounding connecting it to the induction of wound angiogenesis. Finally, ultrasound elastography measured tissue stiffness and visualized growth of new tissue over time. These studies have elegantly captured the physiological sequence of events during the process of wound healing, much of which is anticipated based on certain dynamics in play, to provide the framework for future studies on molecular mechanisms driving these processes. We conclude that the tandem use of non-invasive imaging technologies has the power to provide unprecedented insight into the dynamics of the healing skin tissue.
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Affiliation(s)
- Surya C. Gnyawali
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Kasturi G. Barki
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Shomita S. Mathew-Steiner
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Sriteja Dixith
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Daniel Vanzant
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Jayne Kim
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States of America
| | - Jennifer L. Dickerson
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Soma Datta
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Heather Powell
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States of America
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio, United States of America
| | - Sashwati Roy
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
| | - Valerie Bergdall
- Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Chandan K. Sen
- Comprehensive Wound Center, Davis Heart and Lung Research Institute, Centers for Regenerative Medicine and Cell Based Therapies, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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Schlüter KD, Schulz R, Schreckenberg R. Arginase induction and activation during ischemia and reperfusion and functional consequences for the heart. Front Physiol 2015. [DOI: 10.3389/fphys.2015.00054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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45
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Schlüter KD, Schulz R, Schreckenberg R. Arginase induction and activation during ischemia and reperfusion and functional consequences for the heart. Front Physiol 2015; 6:65. [PMID: 25814956 PMCID: PMC4356066 DOI: 10.3389/fphys.2015.00065] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/07/2015] [Indexed: 12/17/2022] Open
Abstract
Induction and activation of arginase is among the fastest responses of the heart to ischemic events. Induction of arginase expression and enzyme activation under ischemic conditions shifts arginine consumption from nitric oxide formation (NO) to the formation of ornithine and urea. In the heart such a switch in substrate utilization reduces the impact of the NO/cGMP-pathway on cardiac function that requires intact electromechanical coupling but at the same time it induces ornithine-dependent pathways such as the polyamine metabolism. Both effects significantly reduce the recovery of heart function during reperfusion and thereby limits the success of reperfusion strategies. In this context, changes in arginine consumption trigger cardiac remodeling in an unfavorable way and increases the risk of arrhythmia, specifically in the initial post-ischemic period in which arginase activity is dominating. However, during the entire ischemic period arginase activation might be a meaningful adaptation that is specifically relevant for reperfusion following prolonged ischemic periods. Therefore, a precise understanding about the underlying mechanism that leads to arginase induction as well as of it's mechanistic impact on post-ischemic hearts is required for optimizing reperfusion strategies. In this review we will summarize our current understanding of these processes and give an outlook about possible treatment options for the future.
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Affiliation(s)
| | - Rainer Schulz
- Physiologisches Institut, Justus-Liebig-Univiersität Giessen Giessen, Germany
| | - Rolf Schreckenberg
- Physiologisches Institut, Justus-Liebig-Univiersität Giessen Giessen, Germany
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46
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Data integration reveals key homeostatic mechanisms following low dose radiation exposure. Toxicol Appl Pharmacol 2015; 285:1-11. [PMID: 25655199 DOI: 10.1016/j.taap.2015.01.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/21/2015] [Accepted: 01/25/2015] [Indexed: 12/25/2022]
Abstract
The goal of this study was to define pathways regulated by low dose radiation to understand how biological systems respond to subtle perturbations in their environment and prioritize pathways for human health assessment. Using an in vitro 3-D human full thickness skin model, we have examined the temporal response of dermal and epidermal layers to 10 cGy X-ray using transcriptomic, proteomic, phosphoproteomic and metabolomic platforms. Bioinformatics analysis of each dataset independently revealed potential signaling mechanisms affected by low dose radiation, and integrating data shed additional insight into the mechanisms regulating low dose responses in human tissue. We examined direct interactions among datasets (top down approach) and defined several hubs as significant regulators, including transcription factors (YY1, MYC and CREB1), kinases (CDK2, PLK1) and a protease (MMP2). These data indicate a shift in response across time - with an increase in DNA repair, tissue remodeling and repression of cell proliferation acutely (24-72h). Pathway-based integration (bottom up approach) identified common molecular and pathway responses to low dose radiation, including oxidative stress, nitric oxide signaling and transcriptional regulation through the SP1 factor that would not have been identified by the individual data sets. Significant regulation of key downstream metabolites of nitrative stress was measured within these pathways. Among the features identified in our study, the regulation of MMP2 and SP1 was experimentally validated. Our results demonstrate the advantage of data integration to broadly define the pathways and networks that represent the mechanisms by which complex biological systems respond to perturbation.
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47
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Challenges in the Modeling of Wound Healing Mechanisms in Soft Biological Tissues. Ann Biomed Eng 2014; 43:1654-65. [DOI: 10.1007/s10439-014-1200-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 11/19/2014] [Indexed: 02/03/2023]
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48
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Buganza Tepole A, Kuhl E. Computational modeling of chemo-bio-mechanical coupling: a systems-biology approach toward wound healing. Comput Methods Biomech Biomed Engin 2014; 19:13-30. [DOI: 10.1080/10255842.2014.980821] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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49
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Elgharably H, Ganesh K, Dickerson J, Khanna S, Abas M, Ghatak PD, Dixit S, Bergdall V, Roy S, Sen CK. A modified collagen gel dressing promotes angiogenesis in a preclinical swine model of chronic ischemic wounds. Wound Repair Regen 2014; 22:720-9. [PMID: 25224310 PMCID: PMC4380279 DOI: 10.1111/wrr.12229] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/04/2014] [Indexed: 01/23/2023]
Abstract
We recently performed proteomic characterization of a modified collagen gel (MCG) dressing and reported promising effects of the gel in healing full-thickness excisional wounds. In this work, we test the translational relevance of our aforesaid findings by testing the dressing in a swine model of chronic ischemic wounds recently reported by our laboratory. Full-thickness excisional wounds were established in the center of bipedicle ischemic skin flaps on the backs of animals. Ischemia was verified by laser Doppler imaging, and MCG was applied to the test group of wounds. Seven days post wounding, macrophage recruitment to the wound was significantly higher in MCG-treated ischemic wounds. In vitro, MCG up-regulated expression of Mrc-1 (a reparative M2 macrophage marker) and induced the expression of anti-inflammatory cytokine interleukin (IL)-10 and of fibroblast growth factor-basic (β-FGF). An increased expression of CCR2, an M2 macrophage marker, was noted in the macrophages from MCG treated wounds. Furthermore, analyses of wound tissues 7 days post wounding showed up-regulation of transforming growth factor-β, vascular endothelial growth factor, von Willebrand's factor, and collagen type I expression in MCG-treated ischemic wounds. At 21 days post wounding, MCG-treated ischemic wounds displayed higher abundance of proliferating endothelial cells that formed mature vascular structures and increased blood flow to the wound. Fibroblast count was markedly higher in MCG-treated ischemic wound-edge tissue. In addition, MCG-treated wound-edge tissues displayed higher abundance of mature collagen with increased collagen type I : III deposition. Taken together, MCG helped mount a more robust inflammatory response that resolved in a timely manner, followed by an enhanced proliferative phase, angiogenic outcome, and postwound tissue remodeling. Findings of the current study warrant clinical testing of MCG in a setting of ischemic chronic wounds.
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Affiliation(s)
- Haytham Elgharably
- Department of Surgery, Davis Heart & Lung Research Institute, Center for Regenerative Medicine and Cell Based Therapies, Comprehensive Wound Center, The Ohio State University Wexner Medical Center, Columbus, Ohio
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50
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Adolph EJ, Pollins AC, Cardwell NL, Davidson JM, Guelcher SA, Nanney LB. Biodegradable lysine-derived polyurethane scaffolds promote healing in a porcine full-thickness excisional wound model. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2014; 25:1973-85. [PMID: 25290884 DOI: 10.1080/09205063.2014.965997] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lysine-derived polyurethane scaffolds (LTI-PUR) support cutaneous wound healing in loose-skinned small animal models. Due to the physiological and anatomical similarities of human and pig skin, we investigated the capacity of LTI-PUR scaffolds to support wound healing in a porcine excisional wound model. Modifications to scaffold design included the addition of carboxymethylcellulose (CMC) as a porogen to increase interconnectivity and an additional plasma treatment (Plasma) to decrease surface hydrophobicity. All LTI-PUR scaffold and formulations supported cellular infiltration and were biodegradable. At 15 days, CMC and plasma scaffolds simulated increased macrophages more so than LTI PUR or no treatment. This response was consistent with macrophage-mediated oxidative degradation of the lysine component of the scaffolds. Cell proliferation was similar in control and scaffold-treated wounds at 8 and 15 days. Neither apoptosis nor blood vessel area density showed significant differences in the presence of any of the scaffold variations compared with untreated wounds, providing further evidence that these synthetic biomaterials had no adverse effects on those pivotal wound healing processes. During the critical phase of granulation tissue formation in full thickness porcine excisional wounds, LTI-PUR scaffolds supported tissue infiltration, while undergoing biodegradation. Modifications to scaffold fabrication modify the reparative process. This study emphasizes the biocompatibility and favorable cellular responses of PUR scaffolding formulations in a clinically relevant animal model.
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Affiliation(s)
- Elizabeth J Adolph
- a Department of Chemical and Biomolecular Engineering , Vanderbilt University , Nashville , TN , USA
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