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Chen P, Vilorio NC, Dhatariya K, Jeffcoate W, Lobmann R, McIntosh C, Piaggesi A, Steinberg J, Vas P, Viswanathan V, Wu S, Game F. Effectiveness of interventions to enhance healing of chronic foot ulcers in diabetes: A systematic review. Diabetes Metab Res Rev 2024; 40:e3786. [PMID: 38507616 DOI: 10.1002/dmrr.3786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND It is critical that interventions used to enhance the healing of chronic foot ulcers in diabetes are backed by high-quality evidence and cost-effectiveness. In previous years, the systematic review accompanying guidelines published by the International Working Group of the Diabetic Foot performed 4-yearly updates of previous searches, including trials of prospective, cross-sectional and case-control design. AIMS Due to a need to re-evaluate older studies against newer standards of reporting and assessment of risk of bias, we performed a whole new search from conception, but limiting studies to randomised control trials only. MATERIALS AND METHODS For this systematic review, we searched PubMed, Scopus and Web of Science databases for published studies on randomised control trials of interventions to enhance healing of diabetes-related foot ulcers. We only included trials comparing interventions to standard of care. Two independent reviewers selected articles for inclusion and assessed relevant outcomes as well as methodological quality. RESULTS The literature search identified 22,250 articles, of which 262 were selected for full text review across 10 categories of interventions. Overall, the certainty of evidence for a majority of wound healing interventions was low or very low, with moderate evidence existing for two interventions (sucrose-octasulfate and leucocyte, platelet and fibrin patch) and low quality evidence for a further four (hyperbaric oxygen, topical oxygen, placental derived products and negative pressure wound therapy). The majority of interventions had insufficient evidence. CONCLUSION Overall, the evidence to support any other intervention to enhance wound healing is lacking and further high-quality randomised control trials are encouraged.
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Affiliation(s)
- Pam Chen
- Joondalup Health Campus, Ramsay Healthcare Australia, Joondalup, Western Australia, Australia
- Faculty of Health, University of Tasmania, Hobart, Tasmania, Australia
| | - Nalini Campillo Vilorio
- Department of Diabetology, Diabetic Foot Unit, Plaza de la Salud General Hospital, Santo Domingo, Dominican Republic
| | - Ketan Dhatariya
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, UK
- Norwich Medical School, University of East Anglia, Norwich, UK
| | | | - Ralf Lobmann
- Clinic for Endocrinology, Diabetology and Geriatrics, Klinikum Stuttgart, Stuttgart, Germany
| | | | - Alberto Piaggesi
- Diabetic Foot Section, Department of Medicine, University of Pisa, Pisa, Italy
| | - John Steinberg
- Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Prash Vas
- King's College Hospital NHS Foundation Trust, London, UK
| | - Vijay Viswanathan
- MV Hospital for Diabetes and Prof M Viswanathan Diabetes Research Center, Chennai, India
| | - Stephanie Wu
- Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Fran Game
- University Hospitals of Derby and Burton NHS Foundation Trust, Derby, UK
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Chen P, Vilorio NC, Dhatariya K, Jeffcoate W, Lobmann R, McIntosh C, Piaggesi A, Steinberg J, Vas P, Viswanathan V, Wu S, Game F. Guidelines on interventions to enhance healing of foot ulcers in people with diabetes (IWGDF 2023 update). Diabetes Metab Res Rev 2024; 40:e3644. [PMID: 37232034 DOI: 10.1002/dmrr.3644] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 04/17/2023] [Indexed: 05/27/2023]
Abstract
AIMS Principles of wound management, including debridement, wound bed preparation, and newer technologies involving alternation of wound physiology to facilitate healing, are of utmost importance when attempting to heal a chronic diabetes-related foot ulcer. However, the rising incidence and costs of diabetes-related foot ulcer management necessitate that interventions to enhance wound healing of chronic diabetes-related foot ulcers are supported by high-quality evidence of efficacy and cost effectiveness when used in conjunction with established aspects of gold-standard multidisciplinary care. This is the 2023 International Working Group on the Diabetic Foot (IWGDF) evidence-based guideline on wound healing interventions to promote healing of foot ulcers in persons with diabetes. It serves as an update of the 2019 IWGDF guideline. MATERIALS AND METHODS We followed the GRADE approach by devising clinical questions and important outcomes in the Patient-Intervention-Control-Outcome (PICO) format, undertaking a systematic review, developing summary of judgements tables, and writing recommendations and rationale for each question. Each recommendation is based on the evidence found in the systematic review and, using the GRADE summary of judgement items, including desirable and undesirable effects, certainty of evidence, patient values, resources required, cost effectiveness, equity, feasibility, and acceptability, we formulated recommendations that were agreed by the authors and reviewed by independent experts and stakeholders. RESULTS From the results of the systematic review and evidence-to-decision making process, we were able to make 29 separate recommendations. We made a number of conditional supportive recommendations for the use of interventions to improve healing of foot ulcers in people with diabetes. These include the use of sucrose octasulfate dressings, the use of negative pressure wound therapies for post-operative wounds, the use of placental-derived products, the use of the autologous leucocyte/platelet/fibrin patch, the use of topical oxygen therapy, and the use of hyperbaric oxygen. Although in all cases it was stressed that these should be used where best standard of care was not able to heal the wound alone and where resources were available for the interventions. CONCLUSIONS These wound healing recommendations should support improved outcomes for people with diabetes and ulcers of the foot, and we hope that widescale implementation will follow. However, although the certainty of much of the evidence on which to base the recommendations is improving, it remains poor overall. We encourage not more, but better quality trials including those with a health economic analysis, into this area.
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Affiliation(s)
- Pam Chen
- Joondalup Health Campus, Ramsay Healthcare Australia, Joondalup, Western Australia, Australia
- Faculty of Health, University of Tasmania, Hobart, Tasmania, Australia
| | - Nalini Campillo Vilorio
- Department of Diabetology, Diabetic Foot Unit, Plaza de la Salud General Hospital, Santo Domingo, Dominican Republic
| | - Ketan Dhatariya
- Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich, UK
- Norwich Medical School, University of East Anglia, Norwich, UK
| | | | - Ralf Lobmann
- Clinic for Endocrinology, Diabetology and Geriatrics, Klinikum Stuttgart, Stuttgart, Germany
| | - Caroline McIntosh
- Podiatric Medicine, School of Health Sciences, University of Galway, Galway, Ireland
| | - Alberto Piaggesi
- Diabetic Foot Section, Department of Medicine, University of Pisa, Pisa, Italy
| | - John Steinberg
- Georgetown University School of Medicine, Georgetown, Washington DC, USA
| | - Prash Vas
- King's College Hospital NHS Foundation Trust, London, UK
| | - Vijay Viswanathan
- MV Hospital for Diabetes and Prof M Viswanathan Diabetes Research Center, Chennai, India
| | - Stephanie Wu
- Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Fran Game
- University Hospitals of Derby and Burton NHS Foundation Trust, Derby, UK
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Lang JA, Kim J. Remote ischaemic preconditioning - translating cardiovascular benefits to humans. J Physiol 2022; 600:3053-3067. [PMID: 35596644 PMCID: PMC9327506 DOI: 10.1113/jp282568] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/17/2022] [Indexed: 11/26/2022] Open
Abstract
Remote ischaemic preconditioning (RIPC), induced by intermittent periods of limb ischaemia and reperfusion, confers cardiac and vascular protection from subsequent ischaemia–reperfusion (IR) injury. Early animal studies reliably demonstrate that RIPC attenuated infarct size and preserved cardiac tissue. However, translating these adaptations to clinical practice in humans has been challenging. Large clinical studies have found inconsistent results with respect to RIPC eliciting IR injury protection or improving clinical outcomes. Follow‐up studies have implicated several factors that potentially affect the efficacy of RIPC in humans such as age, fitness, frequency, disease state and interactions with medications. Thus, realizing the clinical potential for RIPC may require a human experimental model where confounding factors are more effectively controlled and underlying mechanisms can be further elucidated. In this review, we highlight recent experimental findings in the peripheral circulation that have added valuable insight on the mechanisms and clinical benefit of RIPC in humans. Central to this discussion is the critical role of timing (i.e. immediate vs. delayed effects following a single bout of RIPC) and the frequency of RIPC. Limited evidence in humans has demonstrated that repeated bouts of RIPC over several days uniquely improves vascular function beyond that observed with a single bout alone. Since changes in resistance vessel and microvascular function often precede symptoms and diagnosis of cardiovascular disease, repeated bouts of RIPC may be promising as a preclinical intervention to prevent or delay cardiovascular disease progression.
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Affiliation(s)
- James A Lang
- Department of Kinesiology, Iowa State University, Ames, IA, USA
| | - Jahyun Kim
- Department of Kinesiology, California State University Bakersfield, Bakersfield, CA, USA
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4
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Regulski M, Greenwood T, Leschinsky B. Impact of repeated remote ischemic conditioning on diabetic foot ulcers: A proof-of-concept study. Wound Repair Regen 2021; 29:853-858. [PMID: 34236750 DOI: 10.1111/wrr.12956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 05/23/2021] [Accepted: 06/21/2021] [Indexed: 12/25/2022]
Abstract
Patients with a diabetic foot ulcer (DFU) suffer disabilities and are at increased risk for lower extremity amputation. Current standard of care includes debridement, topical antibiotics, and weight off-loading-still resulting in low rates of healing. Previous small-scale research has indicated that repeated remote ischemic conditioning (rRIC) is a novel modality that delivers significantly higher DFU healing rates. This proof-of-concept study was performed to expand the research on the utility of rRIC as an adjunctive treatment in the healing of chronic DFUs. Forty subjects (41 wounds) received rRIC treatment three times weekly in addition to standard of care for 12 weeks. Subjects that did not heal in this time frame but had a significant reduction in wound size were eligible to continue for an 8-week extension period. By the end of the extension period, 31 of the 41 DFU wounds (75.6%) in this study were determined to be healed. This compares favourably to the 25-30% standard of care average healing rate. For additional comparison, another group of patients receiving standard of care alone, by the same investigator, was selected and matched by wound size at baseline and wound location. For this matching cohort, after 20 weeks of treatment, only 15 of the 41 DFU comparison wounds (36.6%) were determined to be healed, in line with other standard of care results. In the rRIC treatment group, the 10 wounds that did not heal, experienced an average reduction in wound area of 54.3%. The results of this proof-of-concept study reinforce earlier evidence that the addition of rRIC to local wound care significantly improves the healing of chronic diabetic foot ulcers.
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Affiliation(s)
- Matthew Regulski
- Wound Institute of Ocean County, Toms River, New Jersey, USA.,The Center for Wound Healing and Hyperbaric Medicine, Community Medical Center, Toms River, New Jersey, USA.,Kimball Medical Center, Lakewood, New Jersey, USA
| | - Todd Greenwood
- LifeCuff Technologies, Inc., Philadelphia, Pennsylvania, USA
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5
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O'Brien TD. Impaired dermal microvascular reactivity and implications for diabetic wound formation and healing: an evidence review. J Wound Care 2021; 29:S21-S28. [PMID: 32924808 DOI: 10.12968/jowc.2020.29.sup9.s21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diabetic foot ulcers (DFUs) are among the most consequential and costly complications faced by patients with diabetes and the global healthcare system. Acknowledged risk factors for DFUs include diabetic peripheral neuropathy (DPN), peripheral arterial disease (PAD), microtrauma and foot deformities. Research on additional risk factors for DFUs has recently focused on dysregulated, autonomic vasomotor control in the skin of patients with DPN. In particular, impaired dermal microvascular reactivity (IDMR) with its attendant reduction in nutritive capillary blood flow has been identified as an emerging risk factor. This especially relates to refractory wounds noted in patients without overt PAD signs. In this paper, evidence will be reviewed supporting the evolving understanding of IDMR and its impact on DFU formation and healing. Advances in diagnostic instrumentation driving this research along with the most promising potential therapies aimed at improving microvascular function in the diabetic foot will be discussed in brief.
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Affiliation(s)
- Todd D O'Brien
- Penobscot Community Health Care, Bangor, ME, US.,University of Maine, Orono, ME, US
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Maxwell JD, France M, Finnigan LEM, Carter HH, Thijssen DHJ, Jones H. Can exercise training enhance the repeated remote ischaemic preconditioning stimulus on peripheral and cerebrovascular function in high-risk individuals? Eur J Appl Physiol 2021; 121:1167-1178. [PMID: 33507363 PMCID: PMC7966185 DOI: 10.1007/s00421-020-04580-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 11/25/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND Repeated exposure to remote ischaemic preconditioning (rIPC; short bouts of non-lethal ischaemia) enhances peripheral vascular function within 1 week; whereas, longer periods of rIPC (~ 1 year) may improve cerebral perfusion. Increasing the 'dose' of rIPC may lead to superior effects. Given the similarities between exercise and rIPC, we examined whether adding exercise to the rIPC stimulus leads to greater adaptation in systemic vascular function. METHODS Nineteen individuals with increased risk for cardiovascular disease (CVD) were randomly allocated to either 8 weeks of rIPC (n = 9) or 8 weeks of rIPC + exercise (rIPC + Ex) (n = 10). rIPC was applied three times per week in both conditions, and exercise consisted of 50 min (70% heart rate max) of cycling 3 times per week. Peripheral endothelial function was assessed using flow-mediated dilation (FMD) before and after ischaemia-reperfusion (IR). Cerebrovascular function was assessed by dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity (CVR), and cardio-respiratory fitness (VO2peak) using a maximal aerobic capacity test. RESULTS FMD% increased by 1.6% (95% CI, 0.4, 2.8) following rIPC + Ex and by 0.3% (- 1.1, 1.5) in the only rIPC but this did not reach statistical significance (P = 0.65). Neither intervention evoked a change in dCA or in CVR (P > 0.05). VO2peak increased by 2.8 ml/kg/min (1.7, 3.9) following the rIPC + Ex and by 0.1 ml/kg/min (- 1.0, 1.4) following the rIPC only intervention (P = 0.69). CONCLUSION Combining exercise with rIPC across an 8-week intervention does not lead to superior effects in cerebrovascular and peripheral vascular function compared to a repeated rIPC intervention in individuals at risk of CVD.
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Affiliation(s)
- Joseph D Maxwell
- Research Institute of Sports and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK.
| | - Madeleine France
- Research Institute of Sports and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Lucy E M Finnigan
- Research Institute of Sports and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Howard H Carter
- Research Institute of Sports and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK.,Department of Nutrition, Exercise and Sports, Integrative Physiology Group, University of Copenhagen, Copenhagen, Denmark
| | - Dick H J Thijssen
- Research Institute of Sports and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK.,Department of Physiology, Radboud Institute of Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helen Jones
- Research Institute of Sports and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
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7
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Yaseen H, Khamaisi M. Skin well-being in diabetes: Role of macrophages. Cell Immunol 2020; 356:104154. [PMID: 32795665 DOI: 10.1016/j.cellimm.2020.104154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 12/14/2022]
Abstract
Macrophages are key players in wound healing- along with mediating the acute inflammatory response, macrophages activate cutaneous epithelial cells and promote tissue repair. Diabetes complications, including diabetic chronic wounds, are accompanied by persistent inflammation and macrophage malfunction. Several studies indicate that hyperglycemia induces various alterations that affect macrophage function in wound healing including epigenetic changes, imbalance between pro- and anti-inflammatory modulators, and insensitivity to proliferative stimuli. In this review, we briefly summarize recent studies regarding those alterations and their implications on skin well-being in diabetes.
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Affiliation(s)
- Hiba Yaseen
- Department of Medicine D, Rambam Health Care Campus and Ruth & Bruce Rappaport Faculty of Medicine, Technion-IIT Haifa, Israel; Clinical Research Institute, Rambam Health Care Campus, Haifa, Israel
| | - Mogher Khamaisi
- Department of Medicine D, Rambam Health Care Campus and Ruth & Bruce Rappaport Faculty of Medicine, Technion-IIT Haifa, Israel; Clinical Research Institute, Rambam Health Care Campus, Haifa, Israel.
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8
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Zhou D, Ding J, Ya J, Pan L, Wang Y, Ji X, Meng R. Remote ischemic conditioning: a promising therapeutic intervention for multi-organ protection. Aging (Albany NY) 2019; 10:1825-1855. [PMID: 30115811 PMCID: PMC6128414 DOI: 10.18632/aging.101527] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 08/10/2018] [Indexed: 12/21/2022]
Abstract
Despite decades of formidable exploration, multi-organ ischemia-reperfusion injury (IRI) encountered, particularly amongst elderly patients with clinical scenarios, such as age-related arteriosclerotic vascular disease, heart surgery and organ transplantation, is still an unsettled conundrum that besets clinicians. Remote ischemic conditioning (RIC), delivered via transient, repetitive noninvasive IR interventions to distant organs or tissues, is regarded as an innovative approach against IRI. Based on the available evidence, RIC holds the potential of affording protection to multiple organs or tissues, which include not only the heart and brain, but also others that are likely susceptible to IRI, such as the kidney, lung, liver and skin. Neuronal and humoral signaling pathways appear to play requisite roles in the mechanisms of RIC-related beneficial effects, and these pathways also display inseparable interactions with each other. So far, several hurdles lying ahead of clinical translation that remain to be settled, such as establishment of biomarkers, modification of RIC regimen, and deep understanding of underlying minutiae through which RIC exerts its powerful function. As this approach has garnered an increasing interest, herein, we aim to encapsulate an overview of the basic concept and postulated protective mechanisms of RIC, highlight the main findings from proof-of-concept clinical studies in various clinical scenarios, and also to discuss potential obstacles that remain to be conquered. More well designed and comprehensive experimental work or clinical trials are warranted in future research to confirm whether RIC could be utilized as a non-invasive, inexpensive and efficient adjunct therapeutic intervention method for multi-organ protection.
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Affiliation(s)
- Da Zhou
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Jiayue Ding
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Jingyuan Ya
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Liqun Pan
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Yuan Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Xunming Ji
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
| | - Ran Meng
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,National Clinical Research Center for Geriatric Disorders, Beijing, China
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9
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Scientific and Clinical Abstracts From WOCNext 2019. J Wound Ostomy Continence Nurs 2019. [DOI: 10.1097/won.0000000000000530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Sogorski A, Lehnhardt M, Goertz O, Harati K, Kapalschinski N, Hirsch T, Daigeler A, Kolbenschlag J. Improvement of local microcirculation through intermittent Negative Pressure Wound Therapy (NPWT). J Tissue Viability 2018; 27:267-273. [DOI: 10.1016/j.jtv.2018.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/30/2018] [Accepted: 08/12/2018] [Indexed: 01/23/2023]
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11
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Leak RK, Calabrese EJ, Kozumbo WJ, Gidday JM, Johnson TE, Mitchell JR, Ozaki CK, Wetzker R, Bast A, Belz RG, Bøtker HE, Koch S, Mattson MP, Simon RP, Jirtle RL, Andersen ME. Enhancing and Extending Biological Performance and Resilience. Dose Response 2018; 16:1559325818784501. [PMID: 30140178 PMCID: PMC6096685 DOI: 10.1177/1559325818784501] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 05/15/2018] [Indexed: 12/17/2022] Open
Abstract
Human performance, endurance, and resilience have biological limits that are genetically and epigenetically predetermined but perhaps not yet optimized. There are few systematic, rigorous studies on how to raise these limits and reach the true maxima. Achieving this goal might accelerate translation of the theoretical concepts of conditioning, hormesis, and stress adaptation into technological advancements. In 2017, an Air Force-sponsored conference was held at the University of Massachusetts for discipline experts to display data showing that the amplitude and duration of biological performance might be magnified and to discuss whether there might be harmful consequences of exceeding typical maxima. The charge of the workshop was "to examine and discuss and, if possible, recommend approaches to control and exploit endogenous defense mechanisms to enhance the structure and function of biological tissues." The goal of this white paper is to fulfill and extend this workshop charge. First, a few of the established methods to exploit endogenous defense mechanisms are described, based on workshop presentations. Next, the white paper accomplishes the following goals to provide: (1) synthesis and critical analysis of concepts across some of the published work on endogenous defenses, (2) generation of new ideas on augmenting biological performance and resilience, and (3) specific recommendations for researchers to not only examine a wider range of stimulus doses but to also systematically modify the temporal dimension in stimulus inputs (timing, number, frequency, and duration of exposures) and in measurement outputs (interval until assay end point, and lifespan). Thus, a path forward is proposed for researchers hoping to optimize protocols that support human health and longevity, whether in civilians, soldiers, athletes, or the elderly patients. The long-term goal of these specific recommendations is to accelerate the discovery of practical methods to conquer what were once considered intractable constraints on performance maxima.
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Affiliation(s)
- Rehana K. Leak
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA, USA
| | - Edward J. Calabrese
- School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA
| | | | - Jeffrey M. Gidday
- Departments of Ophthalmology, Neuroscience, and Physiology, Louisiana State University School of Medicine, New Orleans, LA, USA
| | - Thomas E. Johnson
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
| | - James R. Mitchell
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - C. Keith Ozaki
- Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Reinhard Wetzker
- Institute for Molecular Cell Biology, University of Jena, Jena, Germany
| | - Aalt Bast
- Department of Pharmacology and Toxicology, Maastricht University, Maastricht, The Netherlands
| | - Regina G. Belz
- Hans-Ruthenberg-Institute, Agroecology Unit, University of Hohenheim, Stuttgart, Germany
| | - Hans E. Bøtker
- Department of Clinical Medicine, Aarhus University Hospital Skejby, Aarhus, Denmark
| | - Sebastian Koch
- Department of Neurology, University of Miami, Miller School of Medicine, FL, USA
| | - Mark P. Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - Roger P. Simon
- Departments of Medicine and Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Randy L. Jirtle
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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12
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Jeffries O, Waldron M, Pattison JR, Patterson SD. Enhanced Local Skeletal Muscle Oxidative Capacity and Microvascular Blood Flow Following 7-Day Ischemic Preconditioning in Healthy Humans. Front Physiol 2018; 9:463. [PMID: 29867526 PMCID: PMC5954802 DOI: 10.3389/fphys.2018.00463] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 04/13/2018] [Indexed: 01/05/2023] Open
Abstract
Ischemic preconditioning (IPC), which involves intermittent periods of ischemia followed by reperfusion, is an effective clinical intervention that reduces the risk of myocardial injury and confers ischemic tolerance to skeletal muscle. Repeated bouts of IPC have been shown to stimulate long-term changes vascular function, however, it is unclear what metabolic adaptations may occur locally in the muscle. Therefore, we investigated 7 days of bilateral lower limb IPC (4 × 5 min) above limb occlusion pressure (220 mmHg; n = 10), or sham (20 mmHg; n = 10), on local muscle oxidative capacity and microvascular blood flow. Oxidative capacity was measured using near-infrared spectroscopy (NIRS) during repeated short duration arterial occlusions (300 mmHg). Microvascular blood flow was assessed during the recovery from submaximal isometric plantar flexion exercises at 40 and 60% of maximal voluntary contraction (MVC). Following the intervention period, beyond the late phase of protection (72 h), muscle oxidative recovery kinetics were speeded by 13% (rate constant pre 2.89 ± 0.47 min-1 vs. post 3.32 ± 0.69 min-1; P < 0.05) and resting muscle oxygen consumption (m O2) was reduced by 16.4% (pre 0.39 ± 0.16%.s-1 vs. post 0.33 ± 0.14%.s-1; P < 0.05). During exercise, changes in deoxygenated hemoglobin (HHb) from rest to steady state were reduced at 40 and 60% MVC (16 and 12%, respectively, P < 0.05) despite similar measures of total hemoglobin (tHb). At the cessation of exercise, the time constant for recovery in oxygenated hemoglobin (O2Hb) was accelerated at 40 and 60% MVC (by 33 and 43%, respectively) suggesting enhanced reoxygenation in the muscle. No changes were reported for systemic measures of resting heart rate or blood pressure. In conclusion, repeated bouts of IPC over 7 consecutive days increased skeletal muscle oxidative capacity and microvascular muscle blood flow. These findings are consistent with enhanced mitochondrial and vascular function following repeated IPC and may be of clinical or sporting interest to enhance or offset reductions in muscle oxidative capacity.
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Affiliation(s)
- Owen Jeffries
- School of Sport, Health and Applied Science, St Mary's University, London, United Kingdom.,School of Biomedical Science, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mark Waldron
- School of Sport, Health and Applied Science, St Mary's University, London, United Kingdom.,School of Science and Technology, University of New England, Armidale, NSW, Australia
| | - John R Pattison
- School of Sport, Health and Applied Science, St Mary's University, London, United Kingdom
| | - Stephen D Patterson
- School of Sport, Health and Applied Science, St Mary's University, London, United Kingdom
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13
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Thijssen DHJ, Maxwell J, Green DJ, Cable NT, Jones H. Repeated ischaemic preconditioning: a novel therapeutic intervention and potential underlying mechanisms. Exp Physiol 2018; 101:677-92. [PMID: 26970535 DOI: 10.1113/ep085566] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/03/2016] [Indexed: 12/13/2022]
Abstract
What is the topic of this review? This review discusses the effects of repeated exposure of tissue to ischaemic preconditioning on cardiovascular function, the attendant adaptations and their potential clinical relevance. What advances does it highlight? We discuss the effects of episodic exposure to ischaemic preconditioning to prevent and/or attenuate ischaemic injury and summarize evidence pertaining to improvements in cardiovascular function and structure. Discussion is provided regarding the potential mechanisms that contribute to both local and systemic adaptation. Findings suggest that clinical benefits result from both the prevention of ischaemic events and the attenuation of their consequences. Ischaemic preconditioning (IPC) refers to the phenomenon whereby short periods of cyclical tissue ischaemia confer subsequent protection against ischaemia-induced injury. As a consequence, IPC can ameliorate the myocardial damage following infarction and can reduce infarct size. The ability of IPC to confer remote protection makes IPC a potentially feasible cardioprotective strategy. In this review, we discuss the concept that repeated exposure of tissue to IPC may increase the 'dose' of protection and subsequently lead to enhanced protection against ischaemia-induced myocardial injury. This may be relevant for clinical populations, who demonstrate attenuated efficacy of IPC to prevent or attenuate ischaemic injury (and therefore myocardial infarct size). Furthermore, episodic IPC facilitates repeated exposure to local (e.g. shear stress) and systemic stimuli (e.g. hormones, cytokines, blood-borne substances), which may induce improvement in vascular function and health. Such adaptation may contribute to prevention of cardio- and cerebrovascular events. The clinical benefits of repeated IPC may, therefore, result from both the prevention of ischaemic events and the attenuation of their consequences. We provide an overview of the literature pertaining to the impact of repeated IPC on cardiovascular function, related to both local and remote adaptation, as well as potential clinical implications.
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Affiliation(s)
- Dick H J Thijssen
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,Radboud Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joseph Maxwell
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Daniel J Green
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia
| | - N Timothy Cable
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,School of Sports Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia.,Department of Sport Science, Aspire Academy, Doha, Qatar
| | - Helen Jones
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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14
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Boghossian JA, Joseph B, Slepian MJ, Armstrong DG. Remote Ischemic Conditioning Promising Potential in Wound Repair in Diabetes?. J Am Podiatr Med Assoc 2017; 107:313-317. [PMID: 28880591 DOI: 10.7547/15-172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Remote ischemic conditioning involves the use of a blood pressure cuff or similar device to induce brief (3-5 min) episodes of limb ischemia. This, in turn, seems to activate a group of distress signals that has shown the potential ability to improve healing of the heart muscle and other organ systems. Until recently, this has not been tested in people with diabetic foot ulcers. The purpose of this review was to provide background on remote ischemic conditioning and recent data to potentially support its use as an adjunct to healing diabetic foot ulcers and other types of tissue loss. We believe that this inexpensive therapy has the potential to be deployed and incorporated into a variety of other therapies to prime patients for healing and to reduce morbidity in patients with this common, complex, and costly complication.
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Affiliation(s)
- Jano A. Boghossian
- Southern Arizona Limb Salvage Alliance, Department of Surgery, University of Arizona College of Medicine, Tucson, AZ. Mr. Boghossian is now with College of Podiatric Medicine, Western University of Health Sciences, Pomona, CA
| | - Bellal Joseph
- Southern Arizona Limb Salvage Alliance, Department of Surgery, University of Arizona College of Medicine, Tucson, AZ. Mr. Boghossian is now with College of Podiatric Medicine, Western University of Health Sciences, Pomona, CA
| | - Marvin J. Slepian
- Southern Arizona Limb Salvage Alliance, Department of Surgery, University of Arizona College of Medicine, Tucson, AZ. Mr. Boghossian is now with College of Podiatric Medicine, Western University of Health Sciences, Pomona, CA
- Arizona Center for Accelerated Biomedical Innovation, University of Arizona College of Medicine, Tucson, AZ
| | - David G. Armstrong
- Southern Arizona Limb Salvage Alliance, Department of Surgery, University of Arizona College of Medicine, Tucson, AZ. Mr. Boghossian is now with College of Podiatric Medicine, Western University of Health Sciences, Pomona, CA
- Arizona Center for Accelerated Biomedical Innovation, University of Arizona College of Medicine, Tucson, AZ
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15
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Abstract
Perioperative myocardial ischemia and infarction are the leading causes of morbidity and mortality following anesthesia and surgery. The discovery of endogenous cardioprotective mechanisms has led to testing of new methods to protect the human heart. These approaches have included ischemic pre-conditioning, per-conditioning, post-conditioning, and remote conditioning of the myocardium. Pre-conditioning and per-conditioning include brief and repetitive periods of sub-lethal ischemia before and during prolonged ischemia, respectively; and post-conditioning is applied at the onset of reperfusion. Remote ischemic conditioning involves transient, repetitive, non-lethal ischemia and reperfusion in one organ or tissue (remote from the heart) that renders myocardium more resistant to lethal ischemia/reperfusion injury. In healthy, young hearts, many conditioning maneuvers can significantly increase the resistance of the heart against ischemia/reperfusion injury. The large multicenter clinical trials with ischemic remote conditioning have not been proven successful in cardiac surgery thus far. The lack of clinical success is due to underlying risk factors that interfere with remote ischemic conditioning and the use of cardioprotective agents that have activated the endogenous cardioprotective mechanisms prior to remote ischemic conditioning. Future preclinical research using remote ischemic conditioning will need to be conducted using comorbid models.
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Affiliation(s)
- Zeljko J Bosnjak
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Zhi-Dong Ge
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
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16
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Remote Ischemic Conditioning Improves Blood Flow and Oxygen Saturation in Pedicled and Free Surgical Flaps. Plast Reconstr Surg 2017; 138:1089-1097. [PMID: 27391830 DOI: 10.1097/prs.0000000000002664] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Surgical flaps have become safe and reliable reconstructive tools, but total flap loss rates as high as 25 percent and partial flap loss rates as high as 36 percent have been reported due to insufficient perfusion. Therefore, a reliable, noninvasive, and effective way to improve the microcirculation of surgical flaps is desirable. The aim of this study was to assess the effect of remote ischemic conditioning on the microcirculation of pedicled and free surgical flaps. METHODS Thirty patients undergoing free (n = 20) and pedicled (n = 10) tissue transfer were included in this study. Remote ischemic conditioning was applied on the upper extremity for three cycles on postoperative days 1, 5, and 12. Blood flow, tissue oxygen saturation, and relative hemoglobin content were measured by means of a combination of laser Doppler and spectroscopy (O2C device) in the flap and the surrounding tissue. The relative increase compared with baseline measurements was assessed. RESULTS Blood flow increased significantly in controls on all 3 postoperative days (p < 0.05 for all). In free flaps, tissue oxygen saturation improved significantly on postoperative days 1 and 12 and blood flow improved significantly on postoperative days 5 and 12 (p < 0.05). In pedicled flaps, blood flow and tissue oxygen saturation increased on postoperative day12, but not significantly. CONCLUSIONS Remote ischemic conditioning is a safe, inexpensive, fast, and reliable method to improve the microcirculation of surgical flaps. Further research is warranted to see whether such an improvement translates into improved flap survival, but it is likely. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.
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17
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Effects of Remote Ischemic Preconditioning on Heme Oxygenase-1 Expression and Cutaneous Wound Repair. Int J Mol Sci 2017; 18:ijms18020438. [PMID: 28218659 PMCID: PMC5343972 DOI: 10.3390/ijms18020438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/06/2017] [Accepted: 02/13/2017] [Indexed: 12/26/2022] Open
Abstract
Skin wounds may lead to scar formation and impaired functionality. Remote ischemic preconditioning (RIPC) can induce the anti-inflammatory enzyme heme oxygenase-1 (HO-1) and protect against tissue injury. We aim to improve cutaneous wound repair by RIPC treatment via induction of HO-1. RIPC was applied to HO-1-luc transgenic mice and HO-1 promoter activity and mRNA expression in skin and several other organs were determined in real-time. In parallel, RIPC was applied directly or 24h prior to excisional wounding in mice to investigate the early and late protective effects of RIPC on cutaneous wound repair, respectively. HO-1 promoter activity was significantly induced on the dorsal side and locally in the kidneys following RIPC treatment. Next, we investigated the origin of this RIPC-induced HO-1 promoter activity and demonstrated increased mRNA in the ligated muscle, heart and kidneys, but not in the skin. RIPC did not change HO-1 mRNA and protein levels in the wound 7 days after cutaneous injury. Both early and late RIPC did not accelerate wound closure nor affect collagen deposition. RIPC induces HO-1 expression in several organs, but not the skin, and did not improve excisional wound repair, suggesting that the skin is insensitive to RIPC-mediated protection.
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18
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Cook M, Smart NA, Van der Touw T. Predicting blood flow responses to rhythmic handgrip exercise from one second isometric contractions. Physiol Res 2016; 65:581-589. [PMID: 26988159 DOI: 10.33549/physiolres.933192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The aim of this work was to predict blood flow responses to rhythmic handgrip exercise from one second isometric contractions. Seven healthy men were studied. Each subject performed a single 1 s handgrip contraction at 10 %, 20 % and 40 % of the maximum handgrip strength. We then repeatedly summed hyperaemic responses from single contractions to predict hyperaemic response to a prolonged bout of rhythmic exercise. There was similarity between steady state brachial blood flow velocity (BBV) extrapolated from single handgrip contractions and during 2 min of rhythmic exercise for 20 % (10.0+/-3.8 cm/s vs. 10.2+/-2.6 cm/s, r=0.93, p=0.003) and 40 % of maximum contractions (14.2+/-5.5 cm/s vs. 15.6+/-3.4 cm/s, r=0.88, p=0.009), but not for 10 % (7.5+/-4.1 cm/s vs. 5.7+/-3.3 cm/s, r=0.94, p=0.018). BBV progressively rose substantially higher during rhythmic contractions than peak BBV observed during single contractions at matched intensity. Respective peak BBV during single contractions and steady state BBV rhythmic contractions were 4.4+/-2.1 and 5.7+/-3.3 cm.s(-1) at 10 % forearm strength (p=0.14), 5.6+/-2.4 and 10.2+/-2.8 cm.s(-1) at 20 % (p=0.002), and 7.0+/-2.5 and 15.6+/-3.6 cm.s(-1) at 40 % (p=0.003). In conclusion, there is similarity between the summated blood flow velocity calculated from a single 1 s muscle contraction and the steady state blood flow velocity response of rhythmic exercise.
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Affiliation(s)
- M Cook
- School of Science and Technology, University of New England, Armidale, Australia.
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Epps JA, Smart NA. Remote ischaemic conditioning in the context of type 2 diabetes and neuropathy: the case for repeat application as a novel therapy for lower extremity ulceration. Cardiovasc Diabetol 2016; 15:130. [PMID: 27613524 PMCID: PMC5018170 DOI: 10.1186/s12933-016-0444-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 08/19/2016] [Indexed: 02/07/2023] Open
Abstract
An emerging treatment modality for reducing damage caused by ischaemia–reperfusion injury is ischaemic conditioning. This technique induces short periods of ischaemia that have been found to protect against a more significant ischaemic insult. Remote ischaemic conditioning (RIC) can be administered more conveniently and safely, by inflation of a pneumatic blood pressure cuff to a suprasystolic pressure on a limb. Protection is then transferred to a remote organ via humoral and neural pathways. The diabetic state is particularly vulnerable to ischaemia–reperfusion injury, and ischaemia is a significant cause of many diabetic complications, including the diabetic foot. Despite this, studies utilising ischaemic conditioning and RIC in type 2 diabetes have often been disappointing. A newer strategy, repeat RIC, involves the repeated application of short periods of limb ischaemia over days or weeks. It has been demonstrated that this improves endothelial function, skin microcirculation, and modulates the systemic inflammatory response. Repeat RIC was recently shown to be beneficial for healing in lower extremity diabetic ulcers. This article summarises the mechanisms of RIC, and the impact that type 2 diabetes may have upon these, with the role of neural mechanisms in the context of diabetic neuropathy a focus. Repeat RIC may show more promise than RIC in type 2 diabetes, and its potential mechanisms and applications will also be explored. Considering the high costs, rates of chronicity and serious complications resulting from diabetic lower extremity ulceration, repeat RIC has the potential to be an effective novel advanced therapy for this condition.
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Affiliation(s)
- J A Epps
- School of Science and Technology, The University of New England, Armidale, NSW, 2351, Australia
| | - N A Smart
- School of Science and Technology, The University of New England, Armidale, NSW, 2351, Australia.
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Repeat remote ischaemic pre-conditioning for improved cardiovascular function in humans: A systematic review. IJC HEART & VASCULATURE 2016; 11:55-58. [PMID: 28616526 PMCID: PMC5441349 DOI: 10.1016/j.ijcha.2016.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/04/2016] [Indexed: 01/17/2023]
Abstract
BACKGROUND Single exposure to remote ischaemic pre-conditioning (RIPC) has been shown to be effective in reducing major adverse events during cardiac surgery. We evaluated the efficacy of repeated exposure RIPC to elicit improvements in cardiovascular function. METHODS A systematic search was conducted up until May 1st, 2015, using the following databases: EMBASE, PubMed (Medline), Web of Science and the Cochrane Central Registry of Controlled Trials (CENTRAL). Data was extracted and synthesized from published studies of repeat RIPC. RESULTS Data from seven studies showed evidence of improvements in vascular function and anti-hypertensive effects of systolic, diastolic and mean arterial blood pressure following repeat RIPC. Currently existing work justifies a systematic review but not data pooling of individual study data. Repeat RIPC has also produced evidence of improvements in endothelial dependent vasodilation, but not non-endothelial dependent vasodilation, cutaneous vascular conductance or cardiorespiratory fitness. CONCLUSION Repeated RIPC exposure has produced evidence of improvements in endothelial dependent vasodilation, ulcer healing and blood pressure but no benefit in non-endothelial dependent vasodilation, cutaneous vascular conductance or cardiorespiratory fitness. The optimal delivery of RIPC remains unclear, but at least 3 or preferably 4, 5 min exposures appears to be most beneficial, at least for reducing blood pressure. Aside from those undertaking cardiac surgery, other study populations with endothelial dysfunction may benefit from repeat exposure to RIPC.
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