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Kinnevey PM, Kearney A, Shore AC, Earls MR, Brennan GI, Poovelikunnel TT, Humphreys H, Coleman DC. Meticillin-susceptible Staphylococcus aureus transmission among healthcare workers, patients and the environment in a large acute hospital under non-outbreak conditions investigated using whole-genome sequencing. J Hosp Infect 2022; 127:15-25. [PMID: 35594983 DOI: 10.1016/j.jhin.2022.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND The role of meticillin-resistant Staphylococcus aureus (MSSA) colonization of healthcare workers (HCWs), patients and the hospital environment in MSSA transmission events (TEs) is poorly understood. AIMS We recently investigated these roles for MRSA under non-outbreak conditions in a large hospital with a history of endemic MRSA over two years using whole-genome sequencing (WGS). Numerous potential MRSA TEs were identified. Here we investigated MSSA TEs from the same sources during the same two-year hospital study. METHODS HCW (N=326) and patient (N=388) volunteers on nine wards were tested for nasal and oral MSSA colonization over two years. Near-patient environment (N=1,164), high-frequency touch sites (N=810) and air (N=445) samples were screened for MSSA. Representative MSSA and clinical isolates were sequenced and analysed by core-genome multilocus-sequence typing (cgMLST). Closely related isolates (≤24 allelic differences) were segregated into related-isolated groups (RIGs). Potential TEs involving MSSA in RIGs from HCWs, patients and patient infections were identified in combination with epidemiological data FINDINGS: In total, 635 MSSA were recovered: clinical isolates (N=82), HCWs (N=170), patients (N=120), environmental isolates (N=263). Twenty-four clonal complexes (CCs) were identified among 406/635 MSSA sequenced, of which 183/406 segregated into 59 RIGs. Numerous potential HCW-to-patient, HCW-to-HCW and patient-to-patient TEs were identified, predominantly among CC5-MSSA, CC30-MSSA and CC45-MSSA. HCW, patient, clinical and environmental isolates were identified in 33, 24, six and 32 RIGs, respectively, with 19/32 of these containing MSSA related to HCW and/or patient isolates. CONCLUSIONS WGS detected numerous potential hospital MSSA TEs involving HCWs, patients and environmental contamination under non-outbreak conditions.
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Affiliation(s)
- P M Kinnevey
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - A Kearney
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland; Department of Infection Control and Prevention, Beaumont Hospital, Dublin, Ireland
| | - A C Shore
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - M R Earls
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - G I Brennan
- National MRSA Reference Laboratory, St. James's Hospital, Dublin, Ireland
| | - T T Poovelikunnel
- Department of Infection Control and Prevention, Beaumont Hospital, Dublin, Ireland; Department of Clinical Microbiology, Royal College of Surgeons in Ireland
| | - H Humphreys
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland; Department of Microbiology, Beaumont Hospital, Dublin, Ireland
| | - D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland.
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Linschoten M, Uijl A, Schut A, Jakob CEM, Romão LR, Bell RM, McFarlane E, Stecher M, Zondag AGM, van Iperen EPA, Hermans-van Ast W, Lea NC, Schaap J, Jewbali LS, Smits PC, Patel RS, Aujayeb A, van der Harst P, Siebelink HJ, van Smeden M, Williams S, Pilgram L, van Gilst WH, Tieleman RG, Williams B, Asselbergs FW, Al-Ali AK, Al-Muhanna FA, Al-Rubaish AM, Al-Windy NYY, Alkhalil M, Almubarak YA, Alnafie AN, Alshahrani M, Alshehri AM, Anning C, Anthonio RL, Badings EA, Ball C, van Beek EA, ten Berg JM, von Bergwelt-Baildon M, Bianco M, Blagova OV, Bleijendaal H, Bor WL, Borgmann S, van Boxem AJM, van den Brink FS, Bucciarelli-Ducci C, van Bussel BCT, Byrom-Goulthorp R, Captur G, Caputo M, Charlotte N, vom Dahl J, Dark P, De Sutter J, Degenhardt C, Delsing CE, Dolff S, Dorman HGR, Drost JT, Eberwein L, Emans ME, Er AG, Ferreira JB, Forner MJ, Friedrichs A, Gabriel L, Groenemeijer BE, Groenendijk AL, Grüner B, Guggemos W, Haerkens-Arends HE, Hanses F, Hedayat B, Heigener D, van der Heijden DJ, Hellou E, Hellwig K, Henkens MTHM, Hermanides RS, Hermans WRM, van Hessen MWJ, Heymans SRB, Hilt AD, van der Horst ICC, Hower M, van Ierssel SH, Isberner N, Jensen B, Kearney MT, van Kesteren HAM, Kielstein JT, Kietselaer BLJH, Kochanek M, Kolk MZH, Koning AMH, Kopylov PY, Kuijper AFM, Kwakkel-van Erp JM, Lanznaster J, van der Linden MMJM, van der Lingen ACJ, Linssen GCM, Lomas D, Maarse M, Macías Ruiz R, Magdelijns FJH, Magro M, Markart P, Martens FMAC, Mazzilli SG, McCann GP, van der Meer P, Meijs MFL, Merle U, Messiaen P, Milovanovic M, Monraats PS, Montagna L, Moriarty A, Moss AJ, Mosterd A, Nadalin S, Nattermann J, Neufang M, Nierop PR, Offerhaus JA, van Ofwegen-Hanekamp CEE, Parker E, Persoon AM, Piepel C, Pinto YM, Poorhosseini H, Prasad S, Raafs AG, Raichle C, Rauschning D, Redón J, Reidinga AC, Ribeiro MIA, Riedel C, Rieg S, Ripley DP, Römmele C, Rothfuss K, Rüddel J, Rüthrich MM, Salah R, Saneei E, Saxena M, Schellings DAAM, Scholte NTB, Schubert J, Seelig J, Shafiee A, Shore AC, Spinner C, Stieglitz S, Strauss R, Sturkenboom NH, Tessitore E, Thomson RJ, Timmermans P, Tio RA, Tjong FVY, Tometten L, Trauth J, den Uil CA, Van Craenenbroeck EM, van Veen HPAA, Vehreschild MJGT, Veldhuis LI, Veneman T, Verschure DO, Voigt I, de Vries JK, van de Wal RMA, Walter L, van de Watering DJ, Westendorp ICD, Westendorp PHM, Westhoff T, Weytjens C, Wierda E, Wille K, de With K, Worm M, Woudstra P, Wu KW, Zaal R, Zaman AG, van der Zee PM, Zijlstra LE, Alling TE, Ahmed R, van Aken K, Bayraktar-Verver ECE, Bermúdez Jiménes FJ, Biolé CA, den Boer-Penning P, Bontje M, Bos M, Bosch L, Broekman M, Broeyer FJF, de Bruijn EAW, Bruinsma S, Cardoso NM, Cosyns B, van Dalen DH, Dekimpe E, Domange J, van Doorn JL, van Doorn P, Dormal F, Drost IMJ, Dunnink A, van Eck JWM, Elshinawy K, Gevers RMM, Gognieva DG, van der Graaf M, Grangeon S, Guclu A, Habib A, Haenen NA, Hamilton K, Handgraaf S, Heidbuchel H, Hendriks-van Woerden M, Hessels-Linnemeijer BM, Hosseini K, Huisman J, Jacobs TC, Jansen SE, Janssen A, Jourdan K, ten Kate GL, van Kempen MJ, Kievit CM, Kleikers P, Knufman N, van der Kooi SE, Koole BAS, Koole MAC, Kui KK, Kuipers-Elferink L, Lemoine I, Lensink E, van Marrewijk V, van Meerbeeck JP, Meijer EJ, Melein AJ, Mesitskaya DF, van Nes CPM, Paris FMA, Perrelli MG, Pieterse-Rots A, Pisters R, Pölkerman BC, van Poppel A, Reinders S, Reitsma MJ, Ruiter AH, Selder JL, van der Sluis A, Sousa AIC, Tajdini M, Tercedor Sánchez L, Van De Heyning CM, Vial H, Vlieghe E, Vonkeman HE, Vreugdenhil P, de Vries TAC, Willems AM, Wils AM, Zoet-Nugteren SK. Clinical presentation, disease course, and outcome of COVID-19 in hospitalized patients with and without pre-existing cardiac disease: a cohort study across 18 countries. Eur Heart J 2022; 43:1104-1120. [PMID: 34734634 DOI: 10.1093/eurheartj/ehab656] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/22/2021] [Accepted: 09/01/2021] [Indexed: 12/25/2022] Open
Abstract
AIMS Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality. METHODS AND RESULTS We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66-75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02-1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10-1.30; P < 0.018) particularly for severe (New York Heart Association class III/IV) heart failure (aRR 1.41, 95% CI 1.20-1.64; P < 0.018). None of the other heart disease subtypes, including ischaemic heart disease, remained significant after multivariable adjustment. Serious cardiac complications were diagnosed in <1% of patients. CONCLUSION Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.
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Kinnevey PM, Kearney A, Shore AC, Earls MR, Brennan G, Poovelikunnel TT, Humphreys H, Coleman DC. Meticillin-resistant Staphylococcus aureus transmission among healthcare workers, patients and the environment in a large acute hospital under non-outbreak conditions investigated using whole-genome sequencing. J Hosp Infect 2021; 118:99-107. [PMID: 34428508 DOI: 10.1016/j.jhin.2021.08.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND The role of meticillin-resistant Staphylococcus aureus (MRSA) colonization of healthcare workers (HCWs), patients and the hospital environment in MRSA transmission in non-outbreak settings is poorly understood. AIMS To investigate transmission events (TEs) involving HCWs, patients and the environment under non-outbreak conditions in a hospital with a history of endemic MRSA using whole-genome sequencing (WGS). METHODS HCW (N = 326) and patient (N = 388) volunteers on nine wards were tested for nasal and oral MRSA colonization over two years. Near-patient environment (N = 1164), high-frequency touch sites (N = 810) and air (N = 445) samples were screened for MRSA. Representative MRSA and clinical isolates were analysed by WGS and core-genome multi-locus sequence typing (cgMLST). Closely related isolates (≤24 allelic differences) were segregated into related isolated groups (RIGs). FINDINGS In total, 155 MRSA were recovered: clinical isolates (N = 41), HCWs (N = 22), patients (N = 37), environmental isolates (N = 55). Nine clonal complexes (CCs) were identified among 110/155 MRSA sequenced with 77/110 assigned to CC22. Seventy-nine MRSA segregated into 17 RIGs. Numerous potential TEs were associated with CC22-MRSA (RIGs 1-15), CC45-MRSA (RIG-16) and CC8-MRSA (RIG-17). RIG-1, (the largest RIG) contained 24 ST22-MRSA-IVh from six HCWs, six patients, four clinical and eight environmental samples recovered over 17 months involving 7/9 wards. TEs involving HCW-to-patient, HCW-to-HCW, patient-to-patient and environmental contamination by HCW/patient isolates were evident. HCW, patient, clinical and environmental isolates were identified in four, nine, seven and 13 RIGs, respectively, with 12/13 of these containing isolates closely related to HCW and/or patient isolates. CONCLUSIONS WGS detected numerous potential hospital MRSA TEs involving HCWs, patients and the environment under non-outbreak conditions.
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Affiliation(s)
- P M Kinnevey
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - A Kearney
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland; Department of Infection Control and Prevention, Beaumont Hospital, Dublin, Ireland
| | - A C Shore
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - M R Earls
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - G Brennan
- National MRSA Reference Laboratory, St James's Hospital, Dublin, Ireland
| | - T T Poovelikunnel
- Department of Infection Control and Prevention, Beaumont Hospital, Dublin, Ireland; Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Ireland
| | - H Humphreys
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Ireland; Department of Microbiology, Beaumont Hospital, Dublin, Ireland
| | - D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland.
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Holm Nielsen S, Edsfeldt A, Tengryd C, Gustafsson H, Shore AC, Natali A, Khan F, Genovese F, Bengtsson E, Karsdal M, Leeming DJ, Nilsson J, Goncalves I. The novel collagen matrikine, endotrophin, is associated with mortality and cardiovascular events in patients with atherosclerosis. J Intern Med 2021; 290:179-189. [PMID: 33951242 PMCID: PMC8359970 DOI: 10.1111/joim.13253] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/27/2020] [Accepted: 12/08/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Rupture of atherosclerotic plaques is the major cause of acute cardiovascular events. The biomarker PRO-C6 measuring Endotrophin, a matrikine of collagen type VI, may provide valuable information detecting subjects in need of intensified strategies for secondary prevention. OBJECTIVE In this study, we evaluate endotrophin in human atherosclerotic plaques and circulating levels of PRO-C6 in patients with atherosclerosis, to determine the predictive potential of the biomarker. METHODS Sections from the stenotic human carotid plaques were stained with the PRO-C6 antibody. PRO-C6 was measured in serum of patients enrolled in the Carotid Plaque Imagining Project (CPIP) (discovery cohort, n = 577) and the innovative medicines initiative surrogate markers for micro- and macrovascular hard end-points for innovative diabetes tools (IMI-SUMMIT, validation cohort, n = 1,378). Median follow-up was 43 months. Kaplan-Meier curves and log-rank tests were performed in the discovery cohort. Cox proportional hazard regression analysis (HR with 95% CI) was used in the discovery cohort and binary logistic regression (OR with 95% CI) in the validation cohort. RESULTS PRO-C6 was localized in the core and shoulder of the atherosclerotic plaque. In the discovery cohort, PRO-C6 independently predicted future cardiovascular events (HR 1.089 [95% CI 1.019 -1.164], p = 0.01), cardiovascular death (HR 1.118 [95% CI 1.008 -1.241], p = 0.04) and all-cause death (HR 1.087 [95% CI 1.008 -1.172], p = 0.03). In the validation cohort, PRO-C6 predicted future cardiovascular events (OR 1.063 [95% CI 1.011 -1.117], p = 0.017). CONCLUSION PRO-C6 is present in the atherosclerotic plaque and associated with future cardiovascular events, cardiovascular death and all-cause mortality in two large prospective cohorts.
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Affiliation(s)
- S Holm Nielsen
- Nordic Bioscience, Herlev, Denmark.,Department of Biomedicine and Biotechnology, Technical University of Denmark, Lyngby, Denmark
| | - A Edsfeldt
- Department of Cardiology, Skåne University Hospital, Malmö, Sweden.,Department of Clinical Sciences, Lund University, Malmö, Sweden.,Wallenberg Center for Molecular Medicine, Lund University, Malmö, Sweden
| | - C Tengryd
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - H Gustafsson
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - A C Shore
- Diabetes and Vascular Medicine, University of Exeter, Medical School, National Institute for Health Research Exeter Clinical Research Facility, Exeter, UK
| | - A Natali
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - F Khan
- Division of Molecular and Clinical medicine, University of Dundee, Dundee, UK
| | | | - E Bengtsson
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | | | | | - J Nilsson
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - I Goncalves
- Department of Cardiology, Skåne University Hospital, Malmö, Sweden.,Department of Clinical Sciences, Lund University, Malmö, Sweden
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McManus BA, Aloba BK, Earls MR, Brennan GI, O'Connell B, Monecke S, Ehricht R, Shore AC, Coleman DC. Multiple distinct outbreaks of Panton-Valentine leucocidin-positive community-associated meticillin-resistant Staphylococcus aureus in Ireland investigated by whole-genome sequencing. J Hosp Infect 2020; 108:72-80. [PMID: 33259881 DOI: 10.1016/j.jhin.2020.11.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND Panton-Valentine leucocidin (PVL)-positive community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) is increasingly associated with infection outbreaks. AIM To investigate multiple suspected PVL-positive CA-MRSA outbreaks using whole-genome sequencing (WGS). METHODS Forty-six suspected outbreak-associated isolates from 36 individuals at three separate Irish hospitals (H1-H3) and from separate incidents involving separate families associated with H2 were investigated by whole-genome multi-locus sequence typing (wgMLST). FINDINGS Two clusters (CH1 and CH2) consisting of 8/10 and 6/6 PVL-positive t008 ST8-MRSA-IVa isolates from H1 and H2, respectively, were identified. Within each cluster, neighbouring isolates were separated by ≤5 allelic differences; however, ≥73 allelic differences were identified between the clusters, indicating two independent outbreaks. Isolates from the H3 maternity unit formed two clusters (CH3-SCI and CH3-SCII) composed of four PVL-negative t4667 ST5-MRSA-V and 14 PVL-positive t002 ST5-MRSA-IVc isolates, respectively. Within clusters, neighbouring isolates were separated by ≤24 allelic differences, whereas both clusters were separated by 1822 allelic differences, indicating two distinct H3 outbreaks. Eight PVL-positive t127 ST1-MRSA-V+fus and three PVL-negative t267 ST97-MRSA-V+fus isolates from two distinct H2-associated families FC1 (N = 4) and FC2 (N = 7) formed three separate clusters (FC1 (t127), FC2 (t127) and FC2 (t267)). Neighbouring isolates within clusters were closely related and exhibited ≤7 allelic differences. Intrafamilial transmission was apparent, but the detection of ≥48 allelic differences between clusters indicated no interfamilial transmission. CONCLUSION The frequent importation of PVL-positive CA-MRSA into healthcare settings, transmission and association with outbreaks is a serious ongoing concern. WGS is a highly discriminatory, informative method for deciphering such outbreaks conclusively.
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Affiliation(s)
- B A McManus
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - B K Aloba
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - M R Earls
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - G I Brennan
- National MRSA Reference Laboratory, St James's Hospital, Dublin, Ireland
| | - B O'Connell
- National MRSA Reference Laboratory, St James's Hospital, Dublin, Ireland
| | - S Monecke
- Leibniz Institute of Photonic Technology (IPHT), Jena, Germany; InfectoGnostics Research Campus Jena e. V., Jena, Germany; Institut fuer Medizinische Mikrobiologie und Hygiene, Medizinische Fakultaet 'Carl Gustav Carus', Dresden, Germany
| | - R Ehricht
- Leibniz Institute of Photonic Technology (IPHT), Jena, Germany; InfectoGnostics Research Campus Jena e. V., Jena, Germany; Friedrich-Schiller University, Institute of Physical Chemistry, Jena, Germany
| | - A C Shore
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland.
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Williams JK, Smallwood MJ, Benjamin N, D'Souza RJ, Shore AC, Winyard PG, Gilchrist M. Renal nitrate clearance in chronic kidney disease. Nitric Oxide 2020; 97:16-19. [PMID: 32007629 DOI: 10.1016/j.niox.2020.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND Nitric oxide (NO) is rapidly oxidised in humans to nitrite and nitrate, with nitrate being present in much greater abundance. These oxidation products can be recycled back into nitric oxide via a complex entero-salivary pathway, thus preserving NO activity. Approximately 65% of circulating nitrate is excreted in the urine in 48 h, with the excretory pathway of the remainder unknown. The effect of declining renal function on nitrate clearance is unknown METHODS: Forty five subjects, 21 M, 24F, median age 69 (range 27-75 years) with renal function assessed by CKD-EPI eGFR between 9 and 89 ml/min/1.73 m2 completed the study. Following a 24 h low nitrate diet a microplate spectrophotometric method was employed to measure plasma nitrate concentration and 24 h urinary nitrate excretion were measured to determine renal nitrate clearance. RESULTS There was a strong positive correlation between urinary nitrate clearance and eGFR, (Spearman R = 0.7665, p < 0.0001) with a moderate negative correlation between plasma nitrate concentration and CKD-EPI eGFR, (Spearman's R = -0.37, p = 0.012). There was a trend between fractional excretion of nitrate and CKD-EPI eGFR (ml/min/1.73 m2) Spearman's R 0.27, p = 0.07 though this did not reach statistical significance. Plasma nitrate concentration and serum creatinine concentration were positively correlated, Spearman's R = 0.39, p = 0.008. CONCLUSIONS We have observed a strong positive association between renal nitrate clearance and renal function such that plasma nitrate rises as renal function falls. Fractional excretion of nitrate appears to decline as renal function falls. As such, urinary nitrate excretion is unlikely to be a reliable marker of endogenous NO synthesis in settings where renal function is altered.
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Affiliation(s)
- J K Williams
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - M J Smallwood
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - N Benjamin
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - R J D'Souza
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - A C Shore
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - P G Winyard
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - M Gilchrist
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK.
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Old OJ, Lloyd GR, Nallala J, Isabelle M, Almond LM, Shepherd NA, Kendall CA, Shore AC, Barr H, Stone N. Rapid infrared mapping for highly accurate automated histology in Barrett's oesophagus. Analyst 2018; 142:1227-1234. [PMID: 27713951 DOI: 10.1039/c6an01871h] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Barrett's oesophagus (BE) is a premalignant condition that can progress to oesophageal adenocarcinoma. Endoscopic surveillance aims to identify potential progression at an early, treatable stage, but generates large numbers of tissue biopsies. Fourier transform infrared (FTIR) mapping was used to develop an automated histology tool for detection of BE and Barrett's neoplasia in tissue biopsies. 22 oesophageal tissue samples were collected from 19 patients. Contiguous frozen tissue sections were taken for pathology review and FTIR imaging. 45 mid-IR images were measured on an Agilent 620 FTIR microscope with an Agilent 670 spectrometer. Each image covering a 140 μm × 140 μm region was measured in 5 minutes, using a 1.1 μm2 pixel size and 64 scans per pixel. Principal component fed linear discriminant analysis was used to build classification models based on spectral differences, which were then tested using leave-one-sample-out cross validation. Key biochemical differences were identified by their spectral signatures: high glycogen content was seen in normal squamous (NSQ) tissue, high glycoprotein content was observed in glandular BE tissue, and high DNA content in dysplasia/adenocarcinoma samples. Classification of normal squamous samples versus 'abnormal' samples (any stage of Barrett's) was performed with 100% sensitivity and specificity. Neoplastic Barrett's (dysplasia or adenocarcinoma) was identified with 95.6% sensitivity and 86.4% specificity. Highly accurate pathology classification can be achieved with FTIR measurement of frozen tissue sections in a clinically applicable timeframe.
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Affiliation(s)
- O J Old
- Gloucestershire Hospitals NHS Foundation Trust, Gloucester, GL1 3NN, UK
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8
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Affiliation(s)
- M D Flynn
- Medical Unit, Postgraduate Medical School, Royal Devon and Exeter Hospital
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9
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Casanova F, Adingupu DD, Adams F, Gooding KM, Looker HC, Aizawa K, Dove F, Elyas S, Belch JJF, Gates PE, Littleford RC, Gilchrist M, Colhoun HM, Shore AC, Khan F, Strain WD. The impact of cardiovascular co-morbidities and duration of diabetes on the association between microvascular function and glycaemic control. Cardiovasc Diabetol 2017; 16:114. [PMID: 28915818 PMCID: PMC5603035 DOI: 10.1186/s12933-017-0594-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/04/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Good glycaemic control in type 2 diabetes (T2DM) protects the microcirculation. Current guidelines suggest glycaemic targets be relaxed in advanced diabetes. We explored whether disease duration or pre-existing macrovascular complications attenuated the association between hyperglycaemia and microvascular function. METHODS 743 participants with T2DM (n = 222), cardiovascular disease (CVD = 183), both (n = 177) or neither (controls = 161) from two centres in the UK, underwent standard clinical measures and endothelial dependent (ACh) and independent (SNP) microvascular function assessment using laser Doppler imaging. RESULTS People with T2DM and CVD had attenuated ACh and SNP responses compared to controls. This was additive in those with both (ANOVA p < 0.001). In regression models, cardiovascular risk factors accounted for attenuated ACh and SNP responses in CVD, whereas HbA1c accounted for the effects of T2DM. HbA1c was associated with ACh and SNP response after adjustment for cardiovascular risk factors (adjusted standardised beta (β) -0.096, p = <0.008 and -0.135, p < 0.001, respectively). Pre-existing CVD did not modify this association (β -0.099; p = 0.006 and -0.138; p < 0.001, respectively). Duration of diabetes accounted for the association between HbA1c and ACh (β -0.043; p = 0.3), but not between HbA1c and SNP (β -0.105; p = 0.02). CONCLUSIONS In those with T2DM and CVD, good glycaemic control is still associated with better microvascular function, whereas in those with prolonged disease this association is lost. This suggests duration of diabetes may be a better surrogate for "advanced disease" than concomitant CVD, although this requires prospective validation.
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Affiliation(s)
- F Casanova
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - D D Adingupu
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - F Adams
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - K M Gooding
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - H C Looker
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - K Aizawa
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - F Dove
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - S Elyas
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - J J F Belch
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - P E Gates
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - R C Littleford
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - M Gilchrist
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - H M Colhoun
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - A C Shore
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK
| | - F Khan
- Vascular and Inflammatory Diseases Research Unit, Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK.
| | - W D Strain
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science and NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Rd, Exeter, EX2 5AX, UK.
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10
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Bell JS, Adio AO, Pitt A, Hayman L, Thorn CE, Shore AC, Whatmore JL, Winlove CP. Microstructure and mechanics of human resistance arteries. Am J Physiol Heart Circ Physiol 2016; 311:H1560-H1568. [PMID: 27663767 PMCID: PMC5206342 DOI: 10.1152/ajpheart.00002.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 09/17/2016] [Indexed: 12/26/2022]
Abstract
Vascular diseases such as diabetes and hypertension cause changes to the vasculature that can lead to vessel stiffening and the loss of vasoactivity. The microstructural bases of these changes are not presently fully understood. We present a new methodology for stain-free visualization, at a microscopic scale, of the morphology of the main passive components of the walls of unfixed resistance arteries and their response to changes in transmural pressure. Human resistance arteries were dissected from subcutaneous fat biopsies, mounted on a perfusion myograph, and imaged at varying transmural pressures using a multimodal nonlinear microscope. High-resolution three-dimensional images of elastic fibers, collagen, and cell nuclei were constructed. The honeycomb structure of the elastic fibers comprising the internal elastic layer became visible at a transmural pressure of 30 mmHg. The adventitia, comprising wavy collagen fibers punctuated by straight elastic fibers, thinned under pressure as the collagen network straightened and pulled taut. Quantitative measurements of fiber orientation were made as a function of pressure. A multilayer analytical model was used to calculate the stiffness and stress in each layer. The adventitia was calculated to be up to 10 times as stiff as the media and experienced up to 8 times the stress, depending on lumen diameter. This work reveals that pressure-induced reorganization of fibrous proteins gives rise to very high local strain fields and highlights the unique mechanical roles of both fibrous networks. It thereby provides a basis for understanding the micromechanical significance of structural changes that occur with age and disease.
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Affiliation(s)
- J S Bell
- Department of Physics, University of Exeter, Exeter, United Kingdom; .,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - A O Adio
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, United Kingdom; and
| | - A Pitt
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, United Kingdom; and
| | - L Hayman
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, United Kingdom; and
| | - C E Thorn
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, United Kingdom; and
| | - A C Shore
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, United Kingdom; and
| | - J L Whatmore
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - C P Winlove
- Department of Physics, University of Exeter, Exeter, United Kingdom
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11
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Iyengar SS, Morgan-Hughes G, Ukoumunne O, Clayton B, Davies EJ, Nikolaou V, Hyde CJ, Shore AC, Roobottom CA. Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients. Clin Radiol 2015; 71:151-8. [PMID: 26703115 DOI: 10.1016/j.crad.2015.10.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 09/09/2015] [Accepted: 10/20/2015] [Indexed: 11/28/2022]
Abstract
AIM To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD). MATERIALS AND METHODS Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥ 50%) stenosis and secondarily as the presence of severe (≥ 70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard. RESULTS No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis. CONCLUSION The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role.
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Affiliation(s)
- S S Iyengar
- Department of Radiology, Plymouth Hospital NHS Trust, Derriford Hospital, Derriford Road, Plymouth, Devon PL6 8DH, UK.
| | - G Morgan-Hughes
- Department of Cardiology, Plymouth Hospital NHS Trust, Derriford Hospital, Derriford Road, Plymouth, Devon PL6 8DH, UK
| | - O Ukoumunne
- Peninsula Collaboration for Leadership in Applied Health Research and Care (PenCLAHRC), NIHR CLAHRC South West Peninsula, Veysey Building, Salmon Pool Lane, Exeter, Devon EX2 4SG, UK
| | - B Clayton
- Department of Cardiology, Plymouth Hospital NHS Trust, Derriford Hospital, Derriford Road, Plymouth, Devon PL6 8DH, UK
| | - E J Davies
- Department of Cardiology, Plymouth Hospital NHS Trust, Derriford Hospital, Derriford Road, Plymouth, Devon PL6 8DH, UK
| | - V Nikolaou
- Peninsula Collaboration for Leadership in Applied Health Research and Care (PenCLAHRC), NIHR CLAHRC South West Peninsula, Veysey Building, Salmon Pool Lane, Exeter, Devon EX2 4SG, UK
| | - C J Hyde
- Peninsula Technology Assessment Group (PenTAG), University of Exeter Medical School, Veysey Building, Salmon Pool Lane, Exeter, Devon EX2 4SG, UK
| | - A C Shore
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Royal Devon and Exeter Foundation NHS Trust, Barrack Road, Exeter, Devon EX2 5DW, UK
| | - C A Roobottom
- Department of Radiology, Plymouth Hospital NHS Trust, Derriford Hospital, Derriford Road, Plymouth, Devon PL6 8DH, UK
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12
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Shore AC, Colhoun HM, Natali A, Palombo C, Östling G, Aizawa K, Kennbäck C, Casanova F, Persson M, Gooding K, Gates PE, Khan F, Looker HC, Adams F, Belch J, Pinnoli S, Venturi E, Morizzo C, Goncalves I, Ladenvall C, Nilsson J. Measures of atherosclerotic burden are associated with clinically manifest cardiovascular disease in type 2 diabetes: a European cross-sectional study. J Intern Med 2015; 278:291-302. [PMID: 25752315 DOI: 10.1111/joim.12359] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND There is a need to develop and validate surrogate markers of cardiovascular disease (CVD) in subjects with diabetes. The macrovascular changes associated with diabetes include aggravated atherosclerosis, increased arterial stiffness and endothelial dysfunction. The aim of this study was to determine which of these factors is most strongly associated with clinically manifest cardiovascular events. METHODS Vascular changes were measured in a cohort of 458 subjects with type 2 diabetes (T2D) and CVD (myocardial infarction, stroke or lower extremity arterial disease), 527 subjects with T2D but without clinically manifest CVD and 515 subjects without T2D and with or without CVD. RESULTS Carotid intima-media thickness (IMT) and ankle-brachial pressure index were independently associated with the presence of CVD in subjects with T2D, whereas pulse wave velocity and endothelial function provided limited independent additive information. Measurement of IMT in the carotid bulb provided better discrimination of the presence of CVD in subjects with T2D than measurement of IMT in the common carotid artery. The factors most significantly associated with increased carotid IMT in T2D were age, disease duration, systolic blood pressure, impaired renal function and increased arterial stiffness, whereas there were no or weak independent associations with metabolic factors and endothelial dysfunction. CONCLUSIONS Measures of atherosclerotic burden are associated with clinically manifest CVD in subjects with T2D. In addition, vascular changes that are not directly related to known metabolic risk factors are important in the development of both atherosclerosis and CVD in T2D. A better understanding of the mechanisms involved is crucial for enabling better identification of CVD risk in T2D.
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Affiliation(s)
- A C Shore
- Diabetes and Vascular Medicine, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, UK
| | - H M Colhoun
- Medical Research Institute, University of Dundee, Dundee, UK
| | - A Natali
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - C Palombo
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy
| | - G Östling
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - K Aizawa
- Diabetes and Vascular Medicine, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, UK
| | - C Kennbäck
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - F Casanova
- Diabetes and Vascular Medicine, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, UK
| | - M Persson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - K Gooding
- Diabetes and Vascular Medicine, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, UK
| | - P E Gates
- Diabetes and Vascular Medicine, University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Exeter, UK
| | - F Khan
- Medical Research Institute, University of Dundee, Dundee, UK
| | - H C Looker
- Medical Research Institute, University of Dundee, Dundee, UK
| | - F Adams
- Medical Research Institute, University of Dundee, Dundee, UK
| | - J Belch
- Medical Research Institute, University of Dundee, Dundee, UK
| | - S Pinnoli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - E Venturi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - C Morizzo
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy
| | - I Goncalves
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - C Ladenvall
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - J Nilsson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
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13
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Burns A, Shore AC, Brennan GI, Coleman DC, Egan J, Fanning S, Galligan MC, Gibbons JF, Gutierrez M, Malhotra-Kumar S, Markey BK, Sabirova JS, Wang J, Leonard FC. A longitudinal study of Staphylococcus aureus colonization in pigs in Ireland. Vet Microbiol 2014; 174:504-513. [PMID: 25465665 DOI: 10.1016/j.vetmic.2014.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/14/2014] [Accepted: 10/16/2014] [Indexed: 02/08/2023]
Abstract
The emergence of methicillin-resistant Staphylococcus aureus (MRSA) in livestock has refocused attention on S. aureus colonization and transmission in pigs. This study investigated the effect of the S. aureus colonization status of a sow on the colonization status of her piglets, and whether pigs carry the same strain of S. aureus throughout production. Nasal swabs were collected from the piglets of six healthy sows two days after birth and two days before and two days after they were moved into each production stage. The average prevalence of S. aureus colonization varied between 26% and 73%. The odds of being S. aureus positive were almost 12 times higher for piglets born to nasal-positive sows than for those born to nasal-negative sows, and three times higher again for piglets born to sows that were both nasal- and vaginal-positive. Isolates recovered from piglets immediately after birth were indistinguishable from those of the dam as determined by phenotypic and molecular typing, including microarray analysis and optical mapping. All isolates belonged to clonal complex 9 and the majority exhibited a novel spa type, t10449. The findings show that the S. aureus colonization status of the sow influences the colonization status of her piglets in the early production stages but strains carried by pigs change over time. Multiresistant S. aureus was detected, in particular post-weaning. Results suggest that sow status and management practices, including mixing of pigs and antimicrobial usage at weaning, should be considered when implementing control measures for S. aureus on a farm.
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Affiliation(s)
- A Burns
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - A C Shore
- Microbiology Research Unit, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland; Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, St. James's Hospital, Dublin 8, Ireland
| | - G I Brennan
- Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, St. James's Hospital, Dublin 8, Ireland
| | - D C Coleman
- Microbiology Research Unit, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland
| | - J Egan
- National Reference Laboratory for Antimicrobial Resistance (Food, Feed and Animal Health), Department of Agriculture, Food and the Marine, Backweston Laboratories, Celbridge, Co. Kildare, Ireland
| | - S Fanning
- School of Public Health, Physiotherapy and Population Science, Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
| | - M C Galligan
- School of Mathematical Sciences, University College Dublin, Belfield, Dublin 4, Ireland
| | - J F Gibbons
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - M Gutierrez
- National Reference Laboratory for Antimicrobial Resistance (Food, Feed and Animal Health), Department of Agriculture, Food and the Marine, Backweston Laboratories, Celbridge, Co. Kildare, Ireland
| | - S Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, Antwerp, Belgium
| | - B K Markey
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - J S Sabirova
- Laboratory of Medical Microbiology, Vaccine & Infectious Diseases Institute, University of Antwerp, Antwerp, Belgium
| | - J Wang
- School of Public Health, Physiotherapy and Population Science, Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
| | - F C Leonard
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
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14
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Pienaar PR, Micklesfield LK, Gill JMR, Shore AC, Gooding KM, Levitt NS, Lambert EV. Ethnic differences in microvascular function in apparently healthy South African men and women. Exp Physiol 2014; 99:985-94. [DOI: 10.1113/expphysiol.2014.078519] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- P. R. Pienaar
- UCT/MRC Research Unit for Exercise Science and Sports Medicine; Department of Human Biology; Faculty of Health Sciences; University of Cape Town; Cape Town South Africa
| | - L. K. Micklesfield
- UCT/MRC Research Unit for Exercise Science and Sports Medicine; Department of Human Biology; Faculty of Health Sciences; University of Cape Town; Cape Town South Africa
- MRC/Wits Developmental Pathways for Health Research Unit; Department of Paediatrics; Faculty of Health Sciences; University of the Witwatersrand; Johannesburg South Africa
| | - J. M. R. Gill
- Institute of Cardiovascular and Medical Sciences; University of Glasgow; Glasgow UK
| | - A. C. Shore
- Diabetes and Vascular Medicine; University of Exeter Medical School and NIHR Exeter Clinical Research Facility; Royal Devon & Exeter NHS Foundation Trust; Exeter UK
| | - K. M. Gooding
- Diabetes and Vascular Medicine; University of Exeter Medical School and NIHR Exeter Clinical Research Facility; Royal Devon & Exeter NHS Foundation Trust; Exeter UK
| | - N. S. Levitt
- Endocrine Unit, Department of Medicine; Faculty of Health Sciences; University of Cape Town; Cape Town South Africa
| | - E. V. Lambert
- UCT/MRC Research Unit for Exercise Science and Sports Medicine; Department of Human Biology; Faculty of Health Sciences; University of Cape Town; Cape Town South Africa
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15
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Creamer E, Shore AC, Deasy EC, Galvin S, Dolan A, Walley N, McHugh S, Fitzgerald-Hughes D, Sullivan DJ, Cunney R, Coleman DC, Humphreys H. Air and surface contamination patterns of meticillin-resistant Staphylococcus aureus on eight acute hospital wards. J Hosp Infect 2014; 86:201-8. [PMID: 24529449 DOI: 10.1016/j.jhin.2013.12.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 12/04/2013] [Indexed: 02/01/2023]
Abstract
BACKGROUND Meticillin-resistant Staphylococcus aureus (MRSA) can be recovered from hospital air and from environmental surfaces. This poses a potential risk of transmission to patients. AIM To investigate associations between MRSA isolates recovered from air and environmental surfaces with those from patients when undertaking extensive patient and environmental sampling. METHODS This was a prospective observational study of patients and their environment in eight wards of a 700-bed tertiary care hospital during 2010 and 2011. Sampling of patients, air and surfaces was carried out on all ward bays, with more extended environmental sampling in ward high-dependency bays and at particular times of the day. The genetic relatedness of isolates was determined by DNA microarray profiling and spa typing. FINDINGS MRSA was recovered from 30/706 (4.3%) patients and from 19/132 (14.4%) air samples. On 9/132 (6.8%) occasions both patient and air samples yielded MRSA. In 32 high-dependency bays, MRSA was recovered from 12/161 (7.4%) patients, 8/32 (25%) air samples, and 21/644 (3.3%) environmental surface samples. On 10/132 (7.6%) occasions, MRSA was isolated from air in the absence of MRSA-positive patients. Patient demographic data combined with spa typing and DNA microarray profiling revealed four likely transmission clusters, where patient and environmental isolates were deemed to be very closely related. CONCLUSION Air sampling yielded MRSA on frequent occasions, especially in high-dependency bays. Environmental and air sampling combined with patient demographic data, spa typing and DNA microarray profiling indicated the presence of clusters that were not otherwise apparent.
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Affiliation(s)
- E Creamer
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - A C Shore
- Microbiology Research Unit, Division of Oral Biosciences, School of Dental Science and Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland; Department of Clinical Microbiology, School of Medicine, University of Dublin, Trinity College, St James's Hospital, Dublin, Ireland
| | - E C Deasy
- Microbiology Research Unit, Division of Oral Biosciences, School of Dental Science and Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland
| | - S Galvin
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - A Dolan
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - N Walley
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - S McHugh
- Department of Surgery, The Royal College of Surgeons in Ireland and Beaumont Hospital, Dublin, Ireland
| | - D Fitzgerald-Hughes
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - D J Sullivan
- Microbiology Research Unit, Division of Oral Biosciences, School of Dental Science and Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Ireland
| | - R Cunney
- Health Protection Surveillance Centre, Dublin, Ireland; Department of Microbiology, Children's University Hospital, Dublin, Ireland
| | - D C Coleman
- Department of Clinical Microbiology, School of Medicine, University of Dublin, Trinity College, St James's Hospital, Dublin, Ireland
| | - H Humphreys
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland; Department of Microbiology, Beaumont Hospital, Dublin, Ireland.
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16
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Creamer E, Shore AC, Rossney AS, Dolan A, Sherlock O, Fitzgerald-Hughes D, Sullivan DJ, Kinnevey PM, O'Lorcain P, Cunney R, Coleman DC, Humphreys H. Transmission of endemic ST22-MRSA-IV on four acute hospital wards investigated using a combination of spa, dru and pulsed-field gel electrophoresis typing. Eur J Clin Microbiol Infect Dis 2012; 31:3151-61. [PMID: 22814876 DOI: 10.1007/s10096-012-1678-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 06/11/2012] [Indexed: 11/24/2022]
Abstract
The transmission of meticillin-resistant Staphylococcus aureus (MRSA) between individual patients is difficult to track in institutions where MRSA is endemic. We investigated the transmission of MRSA where ST22-MRSA-IV is endemic on four wards using demographic data, patient and environmental screening, and molecular typing of isolates. A total of 939 patients were screened, 636 within 72 h of admission (on admission) and 303 >72 h after admission, and 1,252 environmental samples were obtained. Isolates were typed by spa, dru and pulsed-field gel electrophoresis (PFGE) typing. A composite dendrogram generated from the three sets of typing data was used to divide isolates into 'dendrogram groups' (DGs). Ten percent of patients (92/939) were MRSA-positive; 7 % (44/636) on admission and 16 % (48/303) >72 h after admission (p = 0.0007). MRSA was recovered from 5 % of environmental specimens (65/1,252). Most isolates from patients (97 %, 85/88) and the environment (97 %, 63/65) exhibited the ST22-MRSA-IV genotype. Four DGs (DG1, DG4, DG16 and DG17) accounted for 58 % of ST22-MRSA-IV isolates from patients. Epidemiological evidence suggested cross-transmission among 44/92 patients (48 %) but molecular typing confirmed probable cross-transmission in only 11 instances (13 %, 11/88), with the majority of cross-transmission (64 %; 7/11) occurring on one ward. In the setting of highly clonal endemic MRSA, the combination of local epidemiology, PFGE, spa and dru typing provided valuable insights into MRSA transmission.
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Affiliation(s)
- E Creamer
- Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
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17
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Park C, Bathula R, Shore AC, Tillin T, Strain WD, Chaturvedi N, Hughes AD. Impaired post-ischaemic microvascular hyperaemia in Indian Asians is unexplained by diabetes or other cardiovascular risk factors. Atherosclerosis 2011; 221:503-7. [PMID: 22341592 DOI: 10.1016/j.atherosclerosis.2011.11.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 11/07/2011] [Accepted: 11/18/2011] [Indexed: 11/27/2022]
Abstract
OBJECTIVE People of Indian Asian descent have an increased risk of cardiovascular disease (CVD) that cannot be explained by diabetes and other established CVD risk factors. We investigated if microcirculatory function was impaired in a population-based sample of people of Indian Asian descent compared with Europeans in the UK and whether any differences could be accounted for by diabetes or other CVD risk factors. RESEARCH DESIGN AND METHODS Cutaneous microvascular function was assessed using laser Doppler fluximetry in response to heating to 42 °C (maximum hyperaemia) and 3 min arterial occlusion (post occlusive reactive hyperaemia: PORH) in 148 Indian Asians and 147 Europeans. Blood pressure, anthropometry and fasting bloods were also measured. RESULTS Maximum hyperaemia and minimum resistance did not differ significantly by ethnicity. Resting flux and PORH were lower in Indian Asians and time to peak of PORH was prolonged. Diabetes was associated with reduced maximum hyperaemia and PORH. Adjustment for diabetes accounted for differences in resting flux and time to peak but not differences in PORH (Europeans = 45.0 (40.3, 50.1)au, Indian Asians = 35.6 (31.9, 39.7)au, mean (95% confidence interval); p = 0.008 after adjustment). Differences in conventional CVD risk factors did not account for interethnic differences in microvascular responses. CONCLUSIONS People of Indian Asian descent have impaired post-occlusive reactive hyperaemia unexplained by diabetes, dysglycaemia or other CVD risk factors. Abnormal microvascular function in response to ischaemia could represent a novel mechanism contributing to the elevated risk of CVD in Indian Asians.
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Affiliation(s)
- C Park
- International Centre for Circulatory Health, NHLI Division, Faculty of Medicine, Imperial College London & Imperial College Healthcare NHS Trust, London, UK
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Wilkerson DP, Poole DC, Jones AM, Fulford J, Mawson DM, Ball CI, Shore AC. Older Type 2 diabetic males do not exhibit abnormal pulmonary oxygen uptake and muscle oxygen utilization dynamics during submaximal cycling exercise. Am J Physiol Regul Integr Comp Physiol 2011; 300:R685-92. [DOI: 10.1152/ajpregu.00479.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are reports of abnormal pulmonary oxygen uptake (V̇o2) and deoxygenated hemoglobin ([HHb]) kinetics in individuals with Type 2 diabetes (T2D) below 50 yr of age with disease durations of <5 yr. We examined the V̇o2 and muscle [HHb] kinetics in 12 older T2D patients with extended disease durations (age: 65 ± 5 years; disease duration 9.3 ± 3.8 years) and 12 healthy age-matched control participants (CON; age: 62 ± 6 years). Maximal oxygen uptake (V̇o2max) was determined via a ramp incremental cycle test and V̇o2 and [HHb] kinetics were determined during subsequent submaximal step exercise. The V̇o2max was significantly reduced ( P < 0.05) in individuals with T2D compared with CON (1.98 ± 0.43 vs. 2.72 ± 0.40 l/min, respectively) but, surprisingly, V̇o2 kinetics was not different in T2D compared with CON (phase II time constant: 43 ± 17 vs. 41 ± 12 s, respectively). The Δ[HHb]/ΔV̇o2 was significantly higher in T2D compared with CON (235 ± 99 vs. 135 ± 33 AU·l−1·min−1; P < 0.05). Despite a lower V̇o2max, V̇o2 kinetics is not different in older T2D compared with healthy age-matched control participants. The elevated Δ[HHb]/ΔV̇o2 in T2D individuals possibly indicates a compromised muscle blood flow that mandates a greater O2 extraction during exercise. Longer disease duration may result in adaptations in the O2 extraction capabilities of individuals with T2D, thereby mitigating the expected age-related slowing of V̇o2 kinetics.
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Affiliation(s)
- D. P. Wilkerson
- School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, Devon, United Kingdom
| | - D. C. Poole
- School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, Devon, United Kingdom
- Departments of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, Kansas; and
| | - A. M. Jones
- School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, Devon, United Kingdom
| | - J. Fulford
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, and Peninsula National Institute for Health Research, Clinical Research Facility, Devon, United Kingdom
| | - D. M. Mawson
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, and Peninsula National Institute for Health Research, Clinical Research Facility, Devon, United Kingdom
| | - C. I. Ball
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, and Peninsula National Institute for Health Research, Clinical Research Facility, Devon, United Kingdom
| | - A. C. Shore
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, and Peninsula National Institute for Health Research, Clinical Research Facility, Devon, United Kingdom
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Bathula R, Hughes AD, Panerai R, Potter J, Thom SAM, Francis DP, Shore AC, Kooner J, Chaturvedi N. Indian Asians have poorer cardiovascular autonomic function than Europeans: this is due to greater hyperglycaemia and may contribute to their greater risk of heart disease. Diabetologia 2010; 53:2120-8. [PMID: 20549180 DOI: 10.1007/s00125-010-1818-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 05/11/2010] [Indexed: 01/21/2023]
Abstract
AIMS/HYPOTHESIS A high prevalence of diabetes contributes to excess CHD in Indian Asians, but the underlying mechanisms are unclear. Heart rate, heart rate variability (HRV) and baroreflex sensitivity (BRS) are measures of cardiac autonomic function that are disturbed by hyperglycaemia and predict CHD. We compared these measures in Indian Asians and Europeans, and sought explanations for the observed differences. METHODS A representative sample of 149 Europeans and 151 Indian Asians was recruited from primary care, 66% of them men (aged 35-75 years), 34% women (aged 55-75 years). Heart rate, HRV, BRS and cardio-metabolic profiles were measured over four successive 5 min periods with continuous ECG and blood pressure monitoring. RESULTS Indian Asians were hyperglycaemic compared with Europeans (HbA(1c) (mean +/- SD) 6.5 +/- 1.2% vs 5.9 +/- 1.0%, p = 0.001). They had shorter mean RR intervals ((mean +/- SE) 969 +/- 13 vs 1,022 +/- 12 ms, p = 0.002), lower total RR interval power ((geometric mean, 95% CI) 925 [796-1075] vs 1,224 [1,064-1,422] ms(2), p = 0.008) and lower BRS ((mean +/- SE) 5.7 +/- 1.0 vs 6.6 +/- 1.0 ms/mmHg, p = 0.01). All measures of cardiac autonomic dysfunction were significantly associated with hyperglycaemia (mean RR interval vs HbA(1c) r = -0.22; p < 0.001). Ethnic differences in cardiac autonomic function persisted after adjustment for age, blood pressure and medication (mean RR interval 973 vs 1,021 ms, p = 0.004), but were attenuated or abolished by adjusting for HbA(1c) (979 vs 1,014 ms, p = 0.06) or other markers of hyperglycaemia. CONCLUSIONS/INTERPRETATION Indian Asians from the general population have impaired cardiovascular autonomic function compared with Europeans. This is due to greater hyperglycaemia in Indian Asians and may determine their increased CHD risk.
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Affiliation(s)
- R Bathula
- National Heart and Lung Institute, Imperial College Academic Health Sciences Centre, 59-61 North Wharf Road, London W2 1PG, UK
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Gooding KM, Tooke JE, von Lany H, Mitra M, Ling R, Ball CI, Mawson D, Skinner K, Shore AC. Capillary pressure may predict preclinical changes in the eye. Diabetologia 2010; 53:2029-35. [PMID: 20526763 PMCID: PMC2910883 DOI: 10.1007/s00125-010-1805-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 04/30/2010] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Microvascular dysfunction is associated with end-organ damage. Macular oedema is an important component of diabetic retinopathy. Macular thickness can be accurately quantified by optical coherence tomography (OCT), enabling accurate assessment of the macular prior to clinically apparent abnormalities. We investigated whether macular (fovea) thickness in non-diabetic individuals is related to the microvascular variables controlling fluid filtration across a blood vessel wall, in particular capillary pressure and the microvascular filtration capacity (Kf). METHODS We recruited 50 non-diabetic individuals (25 men, 25 women; age range: 26-78 years; BMI range: 20-46 kg/m(2)). Fovea thickness was assessed by OCT. Microvascular assessments included: finger nailfold capillary pressure; Kf; microvascular structural assessments, i.e. skin vasodilatory capacity, minimum vascular resistance (MVR) and microvascular distensibility; and endothelial function. RESULTS At 214.6 (19.9) microm (mean [SD]), fovea thickness was within normal range. Capillary pressure, adjusted for BMI, was associated with fovea thickness (standardised beta 0.573, p = 0.006, linear regression). Fovea thickness was not associated with Kf, microvascular structural assessments or endothelial function. Capillary pressure was still associated with fovea thickness when adjusted for microvascular variables (Kf, vasodilatory capacity, MVR, microvascular distensibility or endothelial function), or for risk factors for diabetes (systemic blood pressure, insulin sensitivity, inflammation, glycaemic status and lipids) and age. CONCLUSIONS/INTERPRETATION Capillary pressure, a key determinant of movement of fluid across a blood vessel wall, is associated with fovea thickness in non-diabetic individuals. This suggests that with regard to potential preventative or therapeutic targets, attention should be directed at the mechanisms determining retinal microvascular pressure.
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Affiliation(s)
- K M Gooding
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, UK.
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Whiteman M, Gooding KM, Whatmore JL, Ball CI, Mawson D, Skinner K, Tooke JE, Shore AC. Adiposity is a major determinant of plasma levels of the novel vasodilator hydrogen sulphide. Diabetologia 2010; 53:1722-6. [PMID: 20414636 DOI: 10.1007/s00125-010-1761-5] [Citation(s) in RCA: 178] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Accepted: 03/12/2010] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS Hydrogen sulphide is a recently identified endogenous endothelium-dependent vasodilator. Animal models of diabetes have shown that low plasma H(2)S levels are associated with marked endothelial dysfunction and insulin resistance. However, human studies on H(2)S and vascular function in health and disease are lacking. METHODS Plasma was obtained from male patients with type 2 diabetes (n = 11), overweight (n = 16) and lean (n = 11) volunteers. H(2)S levels were determined by zinc trap spectrophotometry. Anthropometric measurements (BMI/waist:hip ratio), lipid profile, systemic blood pressure, biochemical indices of diabetes (fasting glucose, insulin sensitivity, Hb(1Ac)) and microvascular function (minimum vascular resistance) were determined. RESULTS Median plasma H(2)S levels (25th, 75th percentiles) in age-matched lean, overweight and type 2 diabetes individuals were 38.9 (29.7, 45.1) micromol/l, 22.0 (18.6, 26.7) micromol/l and 10.5 (4.8, 22.0) micromol/l, respectively. Median plasma H(2)S levels were significantly lower in patients with type 2 diabetes compared with lean (p = 0.001, Mann-Whitney) and overweight participants (p = 0.008). Median plasma H(2)S levels in overweight participants were significantly lower than in lean controls (p = 0.003). Waist circumference was an independent predictor of plasma H(2)S (R (2) = 0.423, standardised beta: -0.650, p < 0.001). This relationship was independent of diabetes, which only contributed a further 5% to the model (R (2) = 0.477). Waist circumference or other measures of adiposity (waist:hip ratio/BMI) remained independent predictors of plasma H(2)S after adjustment for systolic blood pressure, microvascular function, insulin sensitivity, glycaemic control and lipid profile. CONCLUSIONS/INTERPRETATION Plasma H(2)S levels are reduced in overweight participants and patients with type 2 diabetes. Increasing adiposity is a major determinant of plasma H(2)S levels.
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Affiliation(s)
- M Whiteman
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, St Luke's Campus, Magdalen Road, Exeter, Devon EX1 2LU, UK.
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Whiteman M, Gooding KM, Whatmore JL, Skinner K, Ball C, Tooke JE, Shore AC. 026 Plasma levels of the novel vasodilatory gas hydrogen sulphide are associated with adiposity. Heart 2010. [DOI: 10.1136/hrt.2009.191064n] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Scicluna EA, Shore AC, Thürmer A, Ehricht R, Slickers P, Borg MA, Coleman DC, Monecke S. Characterisation of MRSA from Malta and the description of a Maltese epidemic MRSA strain. Eur J Clin Microbiol Infect Dis 2009; 29:163-70. [PMID: 19911206 DOI: 10.1007/s10096-009-0834-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 10/17/2009] [Indexed: 01/09/2023]
Abstract
Malta has one of the highest prevalence rates of methicillin-resistant Staphylococcus aureus (MRSA) in Europe. However, only limited typing data are currently available. In order to address this situation, 45 MRSA isolates from the Mater Dei Hospital in Msida, Malta, were characterised using DNA microarrays. The most common strain was ST22-MRSA-IV (UK-EMRSA-15, 30 isolates). Sporadic strains included ST36-MRSA-II (UK-EMRSA-16, two isolates), PVL-positive ST80-MRSA-IV (European Clone, one isolate), ST228-MRSA-I (Italian Clone/South German Epidemic Strain, one isolate) and ST239-MRSA-III (Vienna/Hungarian/Brazilian Epidemic Strain, one isolate). Ten MRSA isolates belonged to a clonal complex (CC) 5/ST149, spa type t002 strain. This strain harboured an SCCmec IV element (mecA, delta mecR, ugpQ, dcs, ccrA2 and ccrB2), as well as novel alleles of ccrA/B and the fusidic acid resistance element Q6GD50 (previously described in the sequenced strain MSSA476, BX571857.1:SAS0043). It also carried the gene for enterotoxin A (sea) and the egc enterotoxin locus, as well as (in nine out of ten isolates) genes encoding the toxic shock syndrome toxin (tst1) and enterotoxins C and L (sec, sel). While the presence of the other MRSA strains suggests foreign importation due to travel between Malta and other European countries, the CC5/t002 strain appears, so far, to be restricted to Malta.
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Affiliation(s)
- E A Scicluna
- Infection Control Unit, Mater Dei Hospital, Msida, Malta
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McHarg S, Shore AC, Whatmore JL. Heterogeneity of Phospholipase D Activation by Angiotensin II, Lysophosphatidylcholine, and Insulin in Human Endothelial Cells. ACTA ACUST UNITED AC 2009; 15:213-8. [DOI: 10.1080/10623320802228765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Affiliation(s)
- D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland.
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Abstract
AIMS Progressive restrictions placed on insulin-treated patients with diabetes exclude them from driving group 2 and class C1 and D1 vehicles. This reflects an assumption that an increased risk of hypoglycaemia in these patients will cause road traffic accidents. These restrictions have been implemented without any consistent evidence that this is the case. The aim of the study was therefore to investigate whether the rate of road traffic collisions in insulin-treated patients was higher than that of the non-diabetic population using a population register-based study. METHODS A historical cohort study combined information from the Devon and Cornwall Constabulary database on road traffic collisions with the district wide retinal screening database, to provide an anonymized matched database of road traffic collisions in the diabetic population. Accident rates were calculated in the diabetic population and compared to rates in the non-diabetic population using relative risks. RESULTS The estimated overall annual accident rate for the non-diabetic population was 1469 per 100,000 vs. 856 per 100,000 for the diabetic population as a whole (Chi-squared, P < 0.001). On stratification of the groups by age, within the insulin-treated group there was no significant difference in the accident rate compared to the non-diabetic population, with relative risks between 0.51 [confidence interval (CI) 0.25-1.05] and 1.13 (CI 0.88-1.46). CONCLUSIONS Our findings suggest that insulin-treated patients as a group do not pose an increased risk to road safety. They reiterate the need for an individualized risk-based assessment when considering driving restrictions.
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Affiliation(s)
- K F Lonnen
- Diabetes and Vascular Research, Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, UK.
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Coleman DC, O'Donnell MJ, Shore AC, Swan J, Russell RJ. The role of manufacturers in reducing biofilms in dental chair waterlines. J Dent 2007; 35:701-11. [PMID: 17576035 DOI: 10.1016/j.jdent.2007.05.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 05/03/2007] [Accepted: 05/08/2007] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVES This paper reviews how dental chair unit (DCU) manufacturers can contribute practically to resolving the problem of biofilm formation in dental unit waterlines (DUWs). STUDY SELECTION The review concentrates on how novel developments and changes in a range of specific areas have, and might contribute to DUW biofilm control. These include (i) DCU engineering and design changes; (ii) improvements to DCU supply water quality; (iii) development of automated DUW treatment procedures that are effective at controlling biofilm in the long-term, safe for patients and dental staff, environmentally friendly and which do not exhibit adverse effects on DCU components after prolonged use. SOURCES The majority of the material contained in this review is based on, or supported by the peer-reviewed literature. DATA The current consensus from the literature reveals that the emphasis on DUW biofilm and its control has focused on describing the problem and its control using a range of periodic and residual DUW treatment agents. Unfortunately, until recently, DCU manufacturers have provided very little specific guidance in this regard. Indeed, ensuring that DCUs provide good quality output water has generally been regarded to be the responsibility of dental practitioners. Some recent studies have shown that novel DCUs with integral semi-automated or automated DUW cleaning systems can effectively control DUW biofilm in the long-term. However, there are other potential DCU engineering and design changes that DCU manufacturers could undertake to further improve DUW biofilm control. CONCLUSIONS DCU manufacturers can significantly contribute to controlling the problem of DUW biofilm.
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Affiliation(s)
- D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland.
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O'Donnell MJ, Shore AC, Russell RJ, Coleman DC. Optimisation of the long-term efficacy of dental chair waterline disinfection by the identification and rectification of factors associated with waterline disinfection failure. J Dent 2007; 35:438-51. [PMID: 17303302 DOI: 10.1016/j.jdent.2007.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 12/22/2006] [Accepted: 01/03/2007] [Indexed: 11/18/2022] Open
Abstract
UNLABELLED Although many studies have highlighted the problem of biofilm growth in dental chair unit waterlines (DUWs), no long-term studies on the efficacy of DUW disinfection using a large number of dental chair units (DCUs) have been reported. OBJECTIVES To investigate the long-term (21 months) efficacy of the Planmeca Waterline Cleaning System (WCS) to maintain the quality of DUW output water below the American Dental Association (ADA) recommended standard of < or =200cfu/mL of aerobic heterotrophic bacteria using once weekly disinfection with the hydrogen peroxide-and silver ion-containing disinfectant Planosil. METHODS Microbiological quality of DUW output water was monitored by culture on R2A agar for 10 DCUs fitted with the WCS. The presence of biofilm in DUWs was examined by electron microscopy. RESULTS During the first 9 months a high prevalence (28/300 disinfection cycles; 9.3%) of intermittent DUW disinfection failure occurred in 8/10 DCUs due to operator omission to disinfect all DUWs (10/28 failed cycles), incorrect compressed air pressure failing to distribute the disinfectant properly (4/28 failed cycles) and physical blockage of disinfectant intake valves due to corrosion effects of Planosil (14/28 failed cycles). On rectification of these faults through engineering redesign and procedural changes, no further cases of intermittent DUW disinfection failure were observed. Independently of these factors, a rapid and consistent decline in efficacy of DUW disinfection occurred in 4/10 DCUs following the initial 9 months of once weekly disinfection. There was a highly significant difference (P<0.0001) in the prevalence of strongly catalase-positive Novosphingobium and Sphingomonas bacterial species (mean average prevalence of 37.1%) in DUW output water from these 4 DCUs compared to the other 6 DCUs and DCU supply water (prevalence <1%), which correlated with biofilm presence in the DUWs and indicated selective pressure for maintenance of these species by prolonged disinfectant usage. Planosil was reformulated to a more concentrated form (Planosil Forte) and when used once weekly was found to maintain bacterial density in output water below the ADA standard for all 10 DCUs. CONCLUSIONS A variety of factors can contribute to failure of DUW disinfection in the long-term, including human error, disinfectant corrosion of equipment and natural selection of naturally disinfectant-tolerant bacterial species.
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Affiliation(s)
- M J O'Donnell
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
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Hughes AD, Coady E, Raynor S, Mayet J, Wright AR, Shore AC, Kooner JS, Thom SAM, Chaturvedi N. Reduced endothelial progenitor cells in European and South Asian men with atherosclerosis. Eur J Clin Invest 2007; 37:35-41. [PMID: 17181565 PMCID: PMC1869046 DOI: 10.1111/j.1365-2362.2007.01743.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Circulating endothelial progenitor cells (EPCs) play a role in the repair and regeneration of the endothelium and may represent a novel cardiovascular risk factor. South Asian subjects have an increased risk of cardiovascular disease which is not fully explained by known risk factors. This study examined associations of EPCs with atherosclerosis and possible ethnic differences in EPCs. MATERIALS AND METHODS A population sample of 58 European and South Asian adult men was enriched with the recruitment of an additional 59 European and South Asian men with known coronary disease. The coronary artery calcification score was measured by multi-slice computerized tomography (CT), carotid and femoral intima-media thickness (IMT), and femoral plaques were measured by ultrasound. The subjects were further subdivided into three categories of coronary artery disease on the basis of coronary artery calcification score and clinical history. Total EPCs and non-senescent EPCs (ns-EPCs) were quantified after 5 days cell culture and the number of late outgrowth colonies was measured over a 6-week test period. Circulating CD34+ haematopoietic precursor cells were measured by flow cytometry. RESULTS Individuals with femoral plaques had reduced total and ns-EPCs. The number of ns-EPCs were reduced in individuals with the most coronary atheroma and were inversely related to the coronary calcification score and femoral IMT. These relationships persisted after multivariate adjustment for other risk factors. The numbers of late outgrowth colonies or circulating CD34+ cells were unrelated to the presence of atherosclerosis. There were no differences in the number of EPCs between European and South Asian subjects. CONCLUSION The number of EPCs are reduced in subjects with atherosclerosis independent of other risk factors. Reduction in EPC numbers may be an independent risk factor for atherosclerosis but does not explain ethnic differences in cardiovascular risk.
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O'Donnell MJ, Shore AC, Coleman DC. A novel automated waterline cleaning system that facilitates effective and consistent control of microbial biofilm contamination of dental chair unit waterlines: A one-year study. J Dent 2006; 34:648-61. [PMID: 16442201 DOI: 10.1016/j.jdent.2005.12.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 12/02/2005] [Accepted: 12/09/2005] [Indexed: 10/25/2022] Open
Abstract
Microbial contamination of dental chair unit (DCU) output water caused by biofilm growth in dental unit waterlines (DUWs) is a universal problem and a potentially significant source of cross-infection. The microbial quality of output water from a Planmeca Compact i DCU equipped with the novel Water Management System (WMS), an integrated and automated DUW cleaning system, was investigated over a 12-month period with the hydrogen peroxide- and silver ion-containing disinfectants Planosil and Planosil Forte. Four weeks after connection to the potable-water quality mains supply the density of aerobic heterotrophic bacteria, rose from the low levels consistently found in the supply water throughout this study (mean average 77 cfu/mL) to 15,400 cfu/mL. Disinfection of DUWs once weekly with Planosil for 10 weeks resulted in a dramatic reduction in bacterial density immediately following disinfection (mean average 26 cfu/mL). Bacterial density rose steadily between disinfections and by 7 days post-disinfection, water quality failed (mean average 384 cfu/mL) the American Dental Association DCU water quality standard of <or=200 cfu/mL. The DCU was then disinfected once weekly for 40 weeks with Planosil Forte. The average bacterial density immediately post-disinfection was 20 cfu/mL and 7 days post-disinfection was 113 cfu/mL. Electron microscopy showed that improved output water quality following disinfection with both disinfectants was associated with marked elimination of DUW biofilm, but deterioration of water quality following disinfection was associated with its regrowth. The most common bacterial species cultured from the mains water and the DCU output water were Microcococcus luteus and Sphingomonas spp., respectively, the latter of which are known opportunistic pathogens. The findings of this study show that the Planmeca Compact i DCU equipped with the easy to use and automated WMS, that requires minimal effort on the part of the operator, consistently provides output water that passes the ADA quality standard of <or=200 cfu/mL for up to 7 days following once-weekly disinfection with Planosil Forte.
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Affiliation(s)
- M J O'Donnell
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College, Lincoln Place, Dublin 2, Republic of Ireland
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Middlebrooke AR, Elston LM, Macleod KM, Mawson DM, Ball CI, Shore AC, Tooke JE. Six months of aerobic exercise does not improve microvascular function in type 2 diabetes mellitus. Diabetologia 2006; 49:2263-71. [PMID: 16944096 DOI: 10.1007/s00125-006-0361-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 05/22/2006] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Adults with type 2 diabetes mellitus have impaired microvascular function. It has been hypothesised that microvascular function may be restored through regular exercise. The aim of this study was to investigate whether 6 months of regular aerobic exercise would improve microvascular function in adults with type 2 diabetes. MATERIALS AND METHODS Fifty-nine patients with type 2 diabetes (32 males, age 62.9+/-7.6 years, HbA(1c) 6.8+/-0.9%) were randomised to either a 6-month aerobic exercise programme (30 min, three times a week, 70-80% of maximal heart rate) or a 'standard care' control group. Before and after the intervention period, microvascular function was assessed as the maximum skin hyperaemia to local heating and endothelial and non-endothelial responsiveness following the iontophoretic application of acetylcholine and sodium nitroprusside. Maximal oxygen uptake, as an index of aerobic fitness, was assessed using a maximal exercise test. RESULTS No significant improvement was seen in the exercise group compared with the control group for any of the variables measured: maximal oxygen uptake (control pre: 1.73+/-0.53 [means+/-SD] vs post: 1.67+/-0.40; exercise pre: 1.75+/-0.56 vs post: 1.87+/-0.62 l/min, p=0.10); insulin sensitivity (insulin tolerance test) (control pre: -0.17+/-0.06 vs post: -0.17+/-0.06; exercise pre: -0.16+/-0.1 vs post: -0.17+/-0.07 mmol l(-1) min(-1), p=0.97); maximal hyperaemia (control pre: 1.49+/-0.43 vs post: 1.52+/-0.57; exercise pre: 1.42+/-0.36 vs post: 1.47+/-0.33 V, p=0.85); peak response to acetylcholine (control pre: 1.37+/-0.47 vs post: 1.28+/-0.37; exercise pre: 1.27+/-0.44 vs post: 1.44+/-0.23 V, p=0.19) or to sodium nitroprusside (control pre: 1.09+/-0.50 vs post: 1.10+/-0.39; exercise pre: 1.12+/-0.28 vs post: 1.13+/-0.40 V, p=0.98). CONCLUSIONS/INTERPRETATION In this group of type 2 diabetic patients with good glycaemic control a 6-month aerobic exercise programme did not improve microvascular function or aerobic fitness.
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Affiliation(s)
- A R Middlebrooke
- Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, UK.
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Tooke JE, Elston LM, Gooding KM, Ball CI, Mawson DM, Piper J, Sriraman R, Urquhart R, Shore AC. The insulin sensitiser pioglitazone does not influence skin microcirculatory function in patients with type 2 diabetes treated with insulin. Diabetologia 2006; 49:1064-70. [PMID: 16508777 DOI: 10.1007/s00125-006-0168-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 12/06/2005] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Insulin resistance is associated with abnormal microvascular function. Treatment with insulin sensitisers may provoke oedema, suggesting microvascular effects. The mechanisms underlying the peripheral oedema observed during glucose-lowering treatment with thiazolidinediones are unclear. Therefore we examined the effect of pioglitazone on microvascular variables involved in oedema formation. METHODS Subjects (40-80 years) with type 2 diabetes and on insulin were randomised to 9 weeks of pioglitazone therapy (30 mg/day; n=14) or placebo (n=15). The following assessments were performed at baseline and 9 weeks: microvascular filtration capacity; isovolumetric venous pressure; capillary pressure; capillary recruitment following venous or arterial occlusion; postural vasoconstriction; and maximum blood flow. A number of haematological variables were also measured including vascular endothelium growth factor (VEGF), IL-6 and C-reactive protein (CRP). RESULTS Pioglitazone did not significantly influence any microcirculatory variable as compared with placebo (analysis of covariance [ANCOVA] for microvascular filtration capacity for the two groups, p=0.26). Mean VEGF increased with pioglitazone (61.1 pg/ml), but not significantly more than placebo (9.76 pg/ml, p=0.94). HbA(1c) levels and the inflammatory markers IL-6 and CRP decreased with pioglitazone compared with placebo (ANCOVA: p=0.009, p=0.001 and p=0.004, respectively). CONCLUSIONS/INTERPRETATION Pioglitazone improved glycaemic control and inflammatory markers over 9 weeks but had no effect on microcirculatory variables associated with oedema or insulin resistance in type 2 diabetic patients treated with insulin.
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Affiliation(s)
- J E Tooke
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Barrack Road, Exeter, EX2 5AX, UK.
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Abstract
AIMS Abnormalities of microvascular and endothelial function are present in subjects with Type 2 diabetes. Although statin therapy improves cardiovascular risk in diabetes, dyslipidaemia in diabetes may be more responsive to combined statin and fibrate therapy. We examined the effect of cerivastatin and fenofibrate on microvascular function in subjects with Type 2 diabetes with no clinical evidence of cardiovascular disease and near normal lipid levels. METHODS Age-, sex-, lipid- and blood pressure-matched subjects with Type 2 diabetes were randomized in double-blind fashion to one of four treatment groups: group 1 placebo/placebo (n=12), group 2 fenofibrate/placebo (n=10), group 3 cerivastatin/placebo (n=20) and group 4 cerivastatin/fenofibrate (n=11). The subjects were recruited from the Lipid in Diabetes Study. Microvascular function was assessed by skin blood flow response to iontophoresis of acetylcholine and sodium nitroprusside and by skin maximum hyperaemia to local heating. Measurements were carried out at baseline and 3 months later. RESULTS Although all lipid parameters improved in groups 2-4 after 3 months' therapy, no difference was detected in skin blood flow to iontophoresis or maximum hyperaemia in any of the groups. Highly sensitive c-reactive protein (Hs-CRP) did not change with therapy. CONCLUSIONS In conclusion, we were unable to demonstrate any improvement in microvascular endothelial function in non-hyperlipidaemic Type 2 diabetic subjects treated with single or combination lipid-lowering therapy.
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Affiliation(s)
- P G Fegan
- Clinical Microvascular Research, Peninsula Medical School, Exeter, UK.
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Strain WD, Chaturvedi N, Nihoyannopoulos P, Bulpitt CJ, Rajkumar C, Shore AC. Differences in the association between type 2 diabetes and impaired microvascular function among Europeans and African Caribbeans. Diabetologia 2005; 48:2269-77. [PMID: 16193289 DOI: 10.1007/s00125-005-1950-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 07/16/2005] [Indexed: 11/27/2022]
Abstract
AIMS/HYPOTHESIS Diabetes is associated with microvascular damage in all populations, but diabetic patients of Black African descent (African Caribbeans) have a greater risk of vascular target organ damage than would be anticipated for any given blood pressure level. We investigated whether this may be due to differences in the microvasculature. MATERIALS AND METHODS To assess the maximum hyperaemic response to heating and the post-ischaemic response, Laser Doppler fluximetry was performed on 51 and 100 Europeans, and on 66 and 88 African Caribbeans with and without diabetes, respectively. Subjects were aged between 40 and 65 years and recruited from the general population. Echocardiographic interventricular septal thickness (IVST) was measured as a proxy for vascular target organ damage. RESULTS In diabetic subjects of both ethnic groups, the maximum hyperaemic response and peak response to ischaemia were attenuated as compared to the corresponding non-diabetic subjects (p=0.08 for diabetic and 0.03 for non-diabetic Europeans; p=0.03 and 0.1 for African Caribbeans). Adjustment for cardiovascular risk factors, in particular insulin and blood pressure, abolished these differences in Europeans (p=0.8 for diabetic and 0.2 for non-diabetic Europeans), but not in African Caribbeans (p=0.03 and 0.05). CONCLUSIONS/INTERPRETATION Persisting microvascular dysfunction in African Caribbeans may contribute to the increased risk of target organ damage observed in diabetes in this population. The weak contribution of conventional cardiovascular risk factors to these disturbances indicates that conventional therapeutic interventions may be less beneficial in these patients. There was a risk-factor-independent, inverse association between IVST and maximal hyperaemia. These ethnic differences in microvascular responses to temperature and arterial occlusion could account for increased target organ damage in African Caribbeans.
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Affiliation(s)
- W D Strain
- International Centre for Circulatory Health, Faculty of Medicine, Imperial College London at St Mary's, Norfolk Place, London, UK.
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Gooding KM, MacLeod KM, Spyer G, Ewings P, Tooke JE, Shore AC. Impact of hormone replacement therapy on microvascular function in healthy and Type 2 diabetic postmenopausal women. Diabet Med 2005; 22:536-42. [PMID: 15842506 DOI: 10.1111/j.1464-5491.2005.01456.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Hormone replacement therapy (HRT) has been previously reported to modulate vascular function and cardiovascular risk. Its impact on the macrocirculation has previously been explored, however, little data is available on its impact on the microcirculation. This study aimed to determine the impact of HRT on microvascular function in healthy and Type 2 diabetic postmenopausal women (n=20 and 17, respectively). METHODS Microvascular function was assessed by skin maximum hyperaemia, skin hyperaemic response to iontophoretically applied acetylcholine (endothelial-dependent vasodilator) and sodium nitroprusside (endothelial-independent vasodilator), capillary pressure and the microvascular filtration capacity. Microvascular assessments were carried out at baseline and repeated following 6 months' oral hormone replacement therapy (1 mg oestradiol/0.5 mg norethisterone or 1 mg unopposed oestradiol for hysterectomized women). RESULTS Following 6 months' therapy there were no significant changes in microvascular assessments in the healthy women. In the diabetic women there was a reduction in the skin hyperaemic response to acetylcholine [median pretreatment peak response: 1.95 (25th, 75th centiles: 1.54, 2.30) V vs. post-treatment peak response: 1.53 (1.30, 1.91) V (P=0.011, Wilcoxon's signed rank test)] and sodium nitroprusside [median peak response 1.59 (1.37, 1.99) vs. 1.35 (0.92, 1.63) V (P=0.011)] with HRT, but no other changes. CONCLUSION These data suggests that HRT does not affect microvascular function in healthy women, but adversely affects it in diabetic women. These findings may help to explain why HRT fails to provide the predicted cardiovascular protection, and raises the possibility that HRT influences microangiopathy progression in diabetic women.
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Affiliation(s)
- K M Gooding
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, UK.
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Middlebrooke AR, Armstrong N, Welsman JR, Shore AC, Clark P, MacLeod KM. Does aerobic fitness influence microvascular function in healthy adults at risk of developing Type 2 diabetes? Diabet Med 2005; 22:483-9. [PMID: 15787677 DOI: 10.1111/j.1464-5491.2005.01455.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To investigate whether aerobic fitness is associated with skin microvascular function in healthy adults with an increased risk of developing Type 2 diabetes. METHODS Twenty-seven healthy normal glucose-tolerant humans with either a previous diagnosis of gestational diabetes or having two parents with Type 2 diabetes and 27 healthy adults who had no history of diabetes were recruited. Maximal oxygen uptake was assessed using an incremental exercise test to exhaustion. Skin microvascular function was assessed using laser Doppler techniques as the maximum skin hyperaemic response to a thermal stimulus (maximum hyperaemia) and the forearm skin blood flow response to the iontophoretic application of acetylcholine (ACh) and sodium nitroprusside. RESULTS Maximal oxygen uptake was not significantly different in the 'at-risk' group compared with healthy controls. Maximum hyperaemia was reduced in those 'at risk' (1.29 +/- 0.30 vs. 1.46 +/- 0.33 V, P = 0.047); however, the peak response to acetylcholine or sodium nitroprusside did not differ in the two groups. A significant positive correlation was demonstrated between maximal oxygen uptake and maximum hyperaemia (r = 0.52, P = 0.006 l/min and r = 0.60, P = 0.001 ml/kg/min) and peak ACh response (r = 0.40, P = 0.04 l/min and r = 0.47, P = 0.013 ml/kg/min) in the 'at-risk' group when expressed in absolute (l/min) or body mass-related (ml/kg/min) terms. No significant correlations were found in the control group. CONCLUSIONS In this 'at-risk' group with skin microvascular dysfunction maximal oxygen uptake was not reduced compared with healthy controls. However, in the 'at-risk' group alone, individuals with higher levels of aerobic fitness also had better microvascular and endothelial responsiveness.
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Affiliation(s)
- A R Middlebrooke
- Children's Health & Exercise Research Centre, School of Sport & Health Sciences, University of Exeter, Exeter, UK.
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Konopatskaya O, Shore AC, Tooke JE, Whatmore JL. A role for heterotrimeric GTP-binding proteins and ERK1/2 in insulin-mediated, nitric-oxide-dependent, cyclic GMP production in human umbilical vein endothelial cells. Diabetologia 2005; 48:595-604. [PMID: 15739119 DOI: 10.1007/s00125-004-1653-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Accepted: 10/08/2004] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS Insulin is known to stimulate endothelial nitric oxide synthesis, although much remains unknown about the intracellular mechanisms involved. This study aims to examine, in human endothelial cells, the specific contribution of heterotrimeric Gi proteins and extracellular signal-regulated protein kinases 1/2 (ERK1/2) in insulin signalling upstream of nitric-oxide-dependent cyclic GMP production. METHODS Human umbilical vein endothelial cells were treated with 1 nmol/l insulin in the presence or absence of inhibitors of tyrosine kinases (erbstatin), Gi proteins (pertussis toxin) or ERK1/2 (PD098059 or U0126), and nitric oxide production was examined by quantification of intracellular cyclic GMP. Activation/phosphorylation of ERK1/2 by insulin was examined by immunoblotting with specific antibodies, and direct association of the insulin receptor with Gi proteins was examined by immunoprecipitation. RESULTS Treatment of cells with a physiological concentration of insulin (1 nmol/l) for 5 min increased nitric-oxide-dependent cyclic GMP accumulation by 3.3-fold, and this was significantly inhibited by erbstatin. Insulin-stimulated cyclic GMP production was significantly reduced by pertussis toxin and by the inhibitors of ERK1/2, PD098059 and U0126. Immunoblotting indicated that insulin stimulated the phosphorylation of ERK1/2 after 5 min and 1 h, and that this was completely abolished by pertussis toxin, but insensitive to the nitric oxide synthase inhibitor L-NAME. No direct interaction of the insulin receptor beta with Gialpha2 could be demonstrated by immunoprecipitation. CONCLUSIONS/INTERPRETATION This study demonstrates, for the first time, that nitric oxide production induced by physiologically relevant concentrations of insulin, is mediated by the post-receptor activation of a pertussis-sensitive GTP-binding protein and subsequent downstream activation of the ERK1/2 cascade.
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Affiliation(s)
- O Konopatskaya
- Institute for Biomedical and Clinical Science, Peninsula Medical School, Exeter, EX1 2LU, UK.
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McHarg S, Shore AC, Whatmore JL. PC47 LACK OF ACTIVATION OF PHOSPHOLIPASE D BY ENDOTHELIN-1 AND ANGIOTENSIN II IN HUMAN ENDOTHELIAL CELLS. Microcirculation 2004. [DOI: 10.1080/10739680490488869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Mills KF, Price K, Tripp J, MacLoed KM, Tooke JE, Shore AC. OC6 CAN FUTURE MICROVASCULAR COMPLICATIONS BE PREDICTED IN CHILDREN WITH DIABETES USING MAXIMUM BLOOD FLOW? Microcirculation 2004. [DOI: 10.1080/10739680490488166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sriraman R, Hannemann M, Ball C, Mawson D, Shore AC, Tooke JE. PC12 THE INFLUENCE OF SILDENAFIL ON COLOUR DISCRIMINATION AND POTENTIAL EFFECTS ON RETINAL MICROCIRCULATION. Microcirculation 2004. [DOI: 10.1080/10739680490488517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Gooding KM, Whatmore JL, Warland D, Hannemann MM, Middlebrooke AR, Paisley K, Liddell W, Lee B, Tooke JE, Shore AC. PC21 PREDICTORS OF SKIN MINIMUM VASCULAR RESISTANCE IN WOMEN. Microcirculation 2004. [DOI: 10.1080/10739680490488607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
AIMS Nitric oxide (NO) is an important regulator of cardiovascular homeostasis. Lysophosphatidylcholine (lyso-PC), a major constituent of oxidized low density lipoproteins (oxLDL), has been reported to impair nitric oxide-dependent vasodilatation. This study investigated the possible mechanism of the lyso-PC effect on insulin-stimulated NO-dependent of cyclic guanosine 3',5'-monophosphate (cGMP) generation in human endothelial cells. METHODS The intracellular concentration of cGMP in cultured human umbilical vein endothelial cells (HUVECs) was used to estimate NO production. The levels of endothelial nitric oxide synthase (eNOS) protein expression were assessed by Western blotting analyses. RESULTS Both insulin, at physiological concentration, and lyso-PC stimulated rapid and prolonged intracellular of cGMP production, and together induced a marked synergistic response (for short-term stimulation: 1185 +/- 285.9% over control level (100%) compared with insulin and lyso-PC alone (384.8 +/- 67.4% and 357 +/- 205%, respectively; P < 0.001), for long-term stimulation: 3495 +/- 1377%, compared with insulin and lyso-PC alone (663 +/- 131% and 487 +/- 250%, P = 0.002)). Stimulated levels of cGMP accumulation were completely abrogated by NOS inhibitor, indicating NO involvement in the effects of insulin and lyso-PC. Stimulated NO synthesis was not associated with altered eNOS protein expression. Cell subfractionation studies demonstrate that insulin and lyso-PC each alone induced translocation of eNOS from the membrane to the cytosolic compartment and together caused a synergistic translocation. CONCLUSIONS The presented data suggest that insulin and lyso-PC synergistically upregulate endothelial NO production via eNOS translocation from the membrane fraction to the cytosol. This study raises the possibility that an interplay between various factors accompanying diabetes can lead to endothelial NO overproduction or desensitization of NO-dependent responses. Appropriate rather than necessarily high levels of nitric oxide is the determinant of vascular health.
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Affiliation(s)
- O Konopatskaya
- Institute for Biomedical and Clinical Science, Peninsula Medical School, Noy Scott House, Haldon View Terrace, Exeter EX2 5EQ, UK.
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Shore AC, Evans JC, Frayling TM, Clark PM, Lee BC, Horikawa Y, Hattersley AT, Tooke JE. Association of calpain-10 gene with microvascular function. Diabetologia 2002; 45:899-904. [PMID: 12107735 DOI: 10.1007/s00125-002-0847-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2001] [Revised: 02/11/2002] [Indexed: 10/27/2022]
Abstract
AIMS/HYPOTHESIS Genotype could influence vascular function. In some populations, Calpain 10 gene polymorphisms increase susceptibility to diabetes or insulin resistance. Alterations in microvascular function could contribute to insulin resistance. This study investigated whether polymorphisms in the Calpain-10 gene influence microvascular function. METHODS Skin maximum microvascular hyperaemia to local heating on the dorsum of the foot (30 min at 43 degrees C) was measured by Laser Doppler Fluximetry in 37 healthy volunteers. All were normoglycaemic according to World Health Organisation criteria, normotensive and not on any medication. Four polymorphisms in the calpain-10 gene were typed: SNP-44, SNP-43, SNP-19, SNP-63. The SNP common to all the described high risk haplotypes is the G-allele at SNP-43. This intron 3 polymorphism appears to influence gene expression. Microvascular function was examined in relation to polymorphisms at this site alone as well as the effects of the known extended high risk haplotypes using the SNP's above. RESULTS Maximum microvascular hyperaemia was increased in the 21 subjects with G/G genotypes at SNP-43 compared to the combined group of subjects ( G/ A genotype at SNP-43 ( n=12) + A/ A genotype at SNP-43 ( n=4)), and the minimum microvascular resistance was reduced 49.4 (39.6-94.2) vs 67.5 (39.1-107.3) mmHg/V, p=0.007). Haplotype analysis of the hyperaemic response revealed no significant differences between haplotypes. The two groups did not differ in terms of anthropometric measures, blood pressure, insulin resistance or glucose. CONCLUSIONS/INTERPRETATION The polymorphism that confers susceptibility to Type II (non-insulin-dependent) diabetes mellitus in some populations is associated in United Kingdom Caucasians with enhanced microvascular function in the presence of normoglycaemia.
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Affiliation(s)
- A C Shore
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Barrack Road, Exeter, Devon, EX2 5AX, UK.
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Fegan PG, Macleod KM, Tooke JE, Shore AC. n-3 NEFA: vascular implications. Eur Heart J 2002; 23:185-7. [PMID: 11792129 DOI: 10.1053/euhj.2001.2945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Abstract
OBJECTIVES The associations between hypertension, insulin resistance and glucose intolerance are poorly understood. Altered microvascular structure and function could contribute by increasing peripheral vascular resistance and decreasing tissue delivery of glucose. We addressed this hypothesis in a sample of healthy men. METHODS We studied 105 healthy young men aged 23-33 years. Insulin resistance was calculated using the Homeostasis Model Assessment (HOMA). Video capillaroscopy was used on the dorsum of the finger to measure skin capillary density, and in nailfold capillaries to measure capillary blood velocity. Skin vasodilatation was measured with laser Doppler fluximetry on the forearm following heating and iontophoresis of acetylcholine. RESULTS Higher systolic blood pressure was associated with insulin resistance (r=0.31, P<0.005), lower dermal capillary density (r= -0.25, P<0.05), and impaired maximum dermal blood flow after heating (r= -0.26, P<0.01), but not with capillary blood velocity (r=0.07) or dilator responses to acetylcholine (r=0.09). Insulin resistance did not correlate with indices of microvascular structure or function (all r<+/-0.15). However, higher fasting plasma glucose was associated with lower capillary density (r= -0.27, P<0.01), and increased capillary blood velocity (r=0.30, P<0.05). CONCLUSIONS The association between hypertension and insulin resistance is unlikely to be explained by altered microvascular structure and function. However, changes in the microvasculature are found in subjects with early and subtle elevations in blood pressure or fasting plasma glucose in advance of their crossing conventional thresholds for the diagnosis of hypertension or diabetes mellitus.
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Affiliation(s)
- R J Irving
- Department of Medical Sciences, Western General Hospital, University of Edinburgh, Edinburgh EH4 2XU, UK
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Lee BC, Shore AC, Humphreys JM, Lowe GD, Rumley A, Clark PM, Hattersley AT, Tooke JE. Skin microvascular vasodilatory capacity in offspring of two parents with Type 2 diabetes. Diabet Med 2001; 18:541-5. [PMID: 11553182 DOI: 10.1046/j.1464-5491.2001.00514.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Microvascular dysfunction occurs in Type 2 diabetes and in subjects with fasting hyperglycaemia. It is unclear whether this dysfunction relates to dysglycaemia. This study investigated in normogylcaemic individuals whether a genetic predisposition to diabetes, or indices of insulin resistance including endothelial markers, were associated with impaired microvascular function. METHODS Maximum microvascular hyperaemia to local heating of the skin was measured using laser Doppler flowmetry in 21 normoglycaemic subjects with no family history of diabetes (Group 1) and 21 normoglycaemic age, sex and body mass index-matched offspring of two parents with Type 2 diabetes (Group 2). RESULTS Although Group 2 had normal fasting plasma glucose and glucose tolerance tests, the 120-min glucose values were significantly higher at 6.4 (5.3-6.6) mmol/l (median (25th - 75th centile)) than the control group at 4.9 (4.6-5.9) mmol/l (P = 0.005) and the insulinogenic index was lower at 97.1 (60.9-130.8) vs. 124.0 (97.2-177.7) (P = 0.027). Skin maximum microvascular hyperaemia (Group 1: 1.56 (1.39-1.80) vs. Group 2: 1.53 (1.30-1.98) V, P = 0.99) and minimum microvascular resistance which normalizes the hyperaemia data for blood pressure (Group 1: 52.0 (43.2-67.4) vs. Group 2: 56.0 (43.7-69.6) mmHg/V, P = 0.70) did not differ in the two groups. Significant positive associations occurred between minimum microvascular resistance and indices of the insulin resistance syndrome; plasminogen activator inhibitor type 1 (R(s) = 0.46, P = 0.003), t-PA (R(s) = 0.36, P = 0.03), total cholesterol (R(s) = 0.35, P = 0.02), and triglyceride concentration (R(s) = 0.35, P = 0.02), and an inverse association with insulin sensitivity (R(s) = -0.33, P = 0.03). CONCLUSIONS In normoglycaemic adults cutaneous microvascular vasodilatory capacity is associated with features of insulin resistance syndrome, particularly with plasminogen activator inhibitor type 1. A strong family history of Type 2 diabetes alone does not result in impairment in the maximum hyperaemic response. Diabet. Med. 18, 541-545 (2001)
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Affiliation(s)
- B C Lee
- Department of Diabetes and Vascular Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, Exeter, UK
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Abstract
OBJECTIVE Low birth weight has been linked to an increased risk of type 2 diabetes and cardiovascular disease in adult life. The fetal insulin hypothesis proposed that a genetic predisposition to insulin resistance may also influence vascular development. Therefore, impaired vascular function may be an intrinsic abnormality in low-birth weight infants that antedates clinical features of the insulin resistance syndrome. RESEARCH DESIGN AND METHODS Two groups of 3-month-old term infants were included in the study: 17 infants of lowest quartile birth weight (LQBW) and 21 infants of highest quartile birth weight (HQBW). Three aspects of skin microvascular function were examined; response to local heating, response to acetylcholine iontophoresis, and capillary density. RESULTS Median (interquartile ranges) birth weights of the LQBW and HQBW infants were 3,140 g (2,738-3,254) and 3,920 g (3,750-4,020), respectively. Skin maximal hyperemic response to local heating was 2.14 V (1.68-2.30) in the LQBW group vs. 2.44 V (1.96-2.90) in the HQBW group (P = 0.020), and the endothelium-dependent vasodilatory response was 1.03 V (0.62-1.32) in the LQBW group vs. 0.78 V (0.45-1.32) in the HQBW group (P = 0.297). Capillary density in the LQBW and HQBW groups were 46.3 mm(-2) (40.1-53.7) and 44.1 mm(-2) (41.7-56.0), respectively (P = 0.736). CONCLUSIONS Skin maximal hyperemic response was lower in LQBW infants, although no reduction in capillary density or defect in endothelium-dependent vasodilatation was observed. Such a lower maximal hyperemic response in early life in LQBW subjects who are at risk for type 2 diabetes and cardiovascular disease supports the hypothesis that impaired microvascular function is an early antecedent to diabetes in later life.
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Affiliation(s)
- K L Goh
- Diabetes and Vascular Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, Barrack Rd., Exeter, Devon EX2 5AX, U.K
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48
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Abstract
Capillaries play a critical role in cardiovascular function as the point of exchange of nutrients and waste products between the tissues and circulation. Studies of capillary function in man are limited by access to the vascular bed. However, skin capillaries can readily be studied by the technique of capillaroscopy which enables the investigator to assess morphology, density and blood flow velocity. It is also possible to estimate capillary pressure by direct cannulation using glass micropipettes. This review will describe the techniques used to make these assessments and will outline some of the changes that are seen in health and disease.
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Affiliation(s)
- A C Shore
- Department of Diabetes and Vascular Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, EX2 5AX.
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49
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Abstract
Traditional laser Doppler flowmetry (LDF) employs continuous recording of perfusion at one point with time. In order to eliminate the large spatial and temporal fluctuations that occur in the microcirculation, laser Doppler perfusion imaging (LDI) integrates flow readings over a large area. This paper describes a number of experiments to identify some of the characteristics of the LDI, its relationship to flow and no-flow conditions and to compare it with LDF. We undertook experiments to establish the effect of scanner head height, avascular skin thickness and haematocrit on LDI output. We also investigated the contribution of the biological zero signal (the signal obtained from skin when flow is arrested) to the LDI output. LDI output increased with scanner height in vitro and in vivo. Increasing avascular skin thickness reduced the LDI output although linear output characteristics with flow were maintained over the flow range studied. Increasing the haematocrit resulted in a loss of linearity of output with flow at lower velocities. The biological zero signal contributes a similar proportion of the output signal in LDF and LDI. We have presented a series of experiments that will contribute to the understanding of the characteristics of laser Doppler perfusion imaging, its comparison to laser Doppler flowmetry and its relationship to flow and no flow situations. However, our experiments were restricted to one machine, and may not necessarily be applicable to other instruments.
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Affiliation(s)
- D P Kernick
- The Department of Vascular Medicine, Diabetes Research, Postgraduate Medical School, University of Exeter, Devon, UK
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50
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Affiliation(s)
- K Klaentschi
- Department of Diabetes and Vascular Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, United Kingdom
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