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Yang YP, Chiu CT, Chao A, Yeh YC, Sun WZ, Liu CM, Chan WS. An observational study of microcirculation among healthy individuals by age and sex. Clin Hemorheol Microcirc 2024; 86:407-417. [PMID: 38073381 DOI: 10.3233/ch-231807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
OBJECTIVE This study measured normal ranges of microcirculatory parameters in healthy individuals and investigated differences in parameters by age and sex. METHODS Participants were enrolled into three groups with equal numbers of male and female: young (20-39 years), middle-aged (40-59 years), and elderly (60-79 years). Sublingual microcirculation images were obtained using the incident dark field (IDF). RESULTS A total of 75 female and 75 male healthy individuals were enrolled. The elderly group had a higher TVD (26.5 [2] vs. 25.2 [1.8]; p = 0.019) and a lower PPV (97 [2] vs. 98 [3]; p = 0.03) than did the young group. In the elderly group, systolic blood pressure (SBP) and mean arterial pressure (MAP) were moderately and positively correlated with MFI score (r = 0.407, p < 0.05, and r = 0.403, p < 0.05, respectively). The female participants had a lower MFI score than did the male participants (2.9 [2.8-3] vs. 3.0 [2.9-3]; p = 0.015). CONCLUSIONS This study revealed the range of microcirculatory parameters between different ages and sexes in healthy individuals. We found that blood pressure levels were correlated with microcirculatory parameters, especially in elders and female.
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Affiliation(s)
- Yun-Ping Yang
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ching-Tang Chiu
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Anne Chao
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Chang Yeh
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Wei-Zen Sun
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chih-Min Liu
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Wing-Sum Chan
- Department of Anesthesiology, Far Eastern Memorial Hospital, New Taipei, Taiwan
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Lala R, Homes R, Pratt S, Goodwin W, Midwinter M. Comparison of sublingual microcirculatory parameters measured by sidestream darkfield videomicroscopy in anesthetized pigs and adult humans. Animal Model Exp Med 2023; 6:499-503. [PMID: 37661363 PMCID: PMC10614120 DOI: 10.1002/ame2.12348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/11/2023] [Indexed: 09/05/2023] Open
Abstract
BACKGROUND This study aimed to compare sublingual microcirculatory parameters between anesthetized pigs and conscious adult humans using sidestream darkfield videomicroscopy. The overarching aim of the work was to validate the pig as an experimental model of changes in microcirculatory function following traumatic haemorrhagic shock and resuscitation. METHODS Fourteen large white pigs and 14 humans were recruited for the study. Sublingual sidestream darkfield videomicroscopy clips were captured in anesthetized pigs and conscious humans. Clips underwent manual analysis in Automated Vascular Analysis 3.2 software. The total vessel density (TVD), perfused vessel density (PVD), proportion of perfused vessels (PPVs) and microvascular flow index (MFI) were quantified. An independent samples t test was used for between species comparison of microcirculatory parameters. RESULTS AND CONCLUSIONS Conscious humans had a significantly lower TVD, PVD and MFI than anesthetized pigs. No significant difference in PPVs was observed between the species. Perfusion of the microcirculation is a critical determinant of tissue metabolic function and viability. Whilst it may not be surprising that some interspecies differences in the sublingual microcirculatory anatomy were identified between pig and human subjects, it is interesting to report the insignificant difference in PPVs. This direct microcirculatory measure represents a relative change which should hold translatable value across species. We therefore conclude the pig is a suitable model for microcirculatory research and may be a suitable species to investigate changes in microcirculatory perfusion following perturbations in cardiovascular homeostasis, for example during traumatic haemorrhagic shock and resuscitation.
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Affiliation(s)
- Raushan Lala
- School of Biomedical SciencesThe University of QueenslandSt LuciaQldAustralia
- School of Veterinary SciencesThe University of QueenslandGattonQldAustralia
- Jamieson Trauma Institute, Royal Brisbane and Women's HospitalHerstonQldAustralia
- Traumatic Injury Sciences GroupThe University of QueenslandSt LuciaQldAustralia
| | - Ryan Homes
- School of Biomedical SciencesThe University of QueenslandSt LuciaQldAustralia
| | - Shaun Pratt
- School of Veterinary SciencesThe University of QueenslandGattonQldAustralia
- Traumatic Injury Sciences GroupThe University of QueenslandSt LuciaQldAustralia
| | - Wendy Goodwin
- School of Veterinary SciencesThe University of QueenslandGattonQldAustralia
- Traumatic Injury Sciences GroupThe University of QueenslandSt LuciaQldAustralia
| | - Mark Midwinter
- School of Biomedical SciencesThe University of QueenslandSt LuciaQldAustralia
- School of Veterinary SciencesThe University of QueenslandGattonQldAustralia
- Jamieson Trauma Institute, Royal Brisbane and Women's HospitalHerstonQldAustralia
- Traumatic Injury Sciences GroupThe University of QueenslandSt LuciaQldAustralia
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Homes RAP, Giddens F, Francis RS, Hubbard RE, Gordon EH, Midwinter MJ. The sublingual microcirculation and frailty index in chronic kidney disease patients. Microcirculation 2023; 30:e12819. [PMID: 37285445 PMCID: PMC10909441 DOI: 10.1111/micc.12819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/18/2023] [Accepted: 05/25/2023] [Indexed: 06/09/2023]
Abstract
OBJECTIVE To examine the relationship between sublingual microcirculatory measures and frailty index in those attending a kidney transplant assessment clinic. METHODS Patients recruited had their sublingual microcirculation taken using sidestream dark field videomicroscopy (MicroScan, Micro Vision Medical, Amsterdam, the Netherlands) and their frailty index score using a validated short form via interview. RESULTS A total of 44 patients were recruited with two being excluded due to microcirculatory image quality scores exceeding 10. The frailty index score indicated significant correlations with total vessel density (p < .0001, r = -.56), microvascular flow index (p = .004, r = -.43), portion of perfused vessels (p = .0004, r = -.52), heterogeneity index (p = .015, r = .32), and perfused vessel density (p < .0001, r = -.66). No correlation was shown between the frailty index and age (p = .08, r = .27). CONCLUSIONS There is a relationship between the frailty index and microcirculatory health in those attending a kidney transplant assessment clinic, that is not confounded by age. These findings suggest that the impaired microcirculation may be an underlying cause of frailty.
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Affiliation(s)
- Ryan A. P. Homes
- School of Biomedical Science, Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia
| | - Fiona Giddens
- Centre for Health Services Research, Faulty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia
| | - Ross S. Francis
- Department of NephrologyPrincess Alexandra HospitalBrisbaneQueenslandAustralia
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia
| | - Ruth E. Hubbard
- Centre for Health Services Research, Faulty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia
| | - Emily H. Gordon
- Centre for Health Services Research, Faulty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia
| | - Mark J. Midwinter
- School of Biomedical Science, Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia
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Baaten CCFMJ, Vondenhoff S, Noels H. Endothelial Cell Dysfunction and Increased Cardiovascular Risk in Patients With Chronic Kidney Disease. Circ Res 2023; 132:970-992. [PMID: 37053275 PMCID: PMC10097498 DOI: 10.1161/circresaha.123.321752] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The endothelium is considered to be the gatekeeper of the vessel wall, maintaining and regulating vascular integrity. In patients with chronic kidney disease, protective endothelial cell functions are impaired due to the proinflammatory, prothrombotic and uremic environment caused by the decline in kidney function, adding to the increase in cardiovascular complications in this vulnerable patient population. In this review, we discuss endothelial cell functioning in healthy conditions and the contribution of endothelial cell dysfunction to cardiovascular disease. Further, we summarize the phenotypic changes of the endothelium in chronic kidney disease patients and the relation of endothelial cell dysfunction to cardiovascular risk in chronic kidney disease. We also review the mechanisms that underlie endothelial changes in chronic kidney disease and consider potential pharmacological interventions that can ameliorate endothelial health.
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Affiliation(s)
- Constance C F M J Baaten
- Institute for Molecular Cardiovascular Research (IMCAR), University Hospital RWTH Aachen, Aachen, Germany (C.C.F.M.J.B., S.V., H.N.)
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands (C.C.F.M.J.B., H.N.)
| | - Sonja Vondenhoff
- Institute for Molecular Cardiovascular Research (IMCAR), University Hospital RWTH Aachen, Aachen, Germany (C.C.F.M.J.B., S.V., H.N.)
| | - Heidi Noels
- Institute for Molecular Cardiovascular Research (IMCAR), University Hospital RWTH Aachen, Aachen, Germany (C.C.F.M.J.B., S.V., H.N.)
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands (C.C.F.M.J.B., H.N.)
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5
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Wang YC, Wang MJ, Lee CY, Chen CC, Chiu CT, Chao A, Chan WS, Tsai MK, Yeh YC. Effects of perioperative dexmedetomidine infusion on renal function and microcirculation in kidney transplant recipients: a randomised controlled trial. Ann Med 2022; 54:1233-1243. [PMID: 35486415 PMCID: PMC9126588 DOI: 10.1080/07853890.2022.2067351] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Ischemia-reperfusion injury affects postoperative transplanted kidney function in kidney transplant recipients. Dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation, but its propensity to cause bradycardia and hypotension may adversely affect microcirculation. This study investigated the effect of dexmedetomidine on postoperative renal function and sublingual microcirculation in kidney recipients. METHODS The enrolled kidney transplant recipients were randomly allocated to the control group or dexmedetomidine group. After anaesthesia induction, patients in the dexmedetomidine group received dexmedetomidine infusion until 2 h after surgery. Sublingual microcirculation was recorded using an incident dark-field video microscope and analysed. The primary outcomes were the creatinine level on a postoperative day 2 and total vessel density at 2 h after surgery. RESULTS A total of 60 kidney recipients were analysed, and the creatinine levels on postoperative day 2 were significantly lower in the dexmedetomidine group than in the control group (1.5 (1.1-2.4) vs. 2.2 (1.7-3.0) mg/dL, median difference -0.6 (95% CI, -0.7 to -0.5) mg/dL, p = .018). On a postoperative day 7, the creatinine levels did not differ significantly between the two groups. Total vessel density at 2 h after surgery did not differ significantly between the two groups. CONCLUSION We found that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine infusion, but total vessel density was not significantly different between the intervention and control groups. Key messagesIschemia-reperfusion injury affects postoperative transplanted kidney function, and dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation in other clinical conditions.This study showed that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine.Dexmedetomidine's side effect of bradycardia and hypotension may affect microcirculation, our results revealed that the perioperative sublingual microcirculation did not differ significantly in kidney transplant recipients receiving dexmedetomidine.
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Affiliation(s)
- Yin-Chin Wang
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ming-Jiuh Wang
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chih-Yuan Lee
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | - Chien-Chia Chen
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | - Ching-Tang Chiu
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Anne Chao
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Wing-Sum Chan
- Department of Anesthesiology, Far Eastern Memorial Hospital, New Taipei, Taiwan
| | - Meng-Kun Tsai
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.,Department of Surgery, National Taiwan University Hospital, Hsin-Chu Branch, Hsinchu City, Taiwan
| | - Yu-Chang Yeh
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
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6
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Assessment of microcirculatory function during hemodialysis. Curr Opin Nephrol Hypertens 2022; 31:553-559. [PMID: 36172854 DOI: 10.1097/mnh.0000000000000831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Patients with chronic kidney disease characteristically exhibit microcirculatory dysfunction, in combination with vascular damage. Hemodialysis superimposes additional circulatory stress to the microvasculature (repetitive ischemic insults/cumulative damage) resulting in high mortality. Intradialytic monitoring and hemodialysis delivery is currently limited to macrovascular/systemic assessment and detection of intradialytic systemic hypotension. Monitoring of the microcirculation has the potential to provide valuable information on hemodialysis-induced circulatory stress likely to result in end-organ ischemia (with/without systemic hypotension) generating an opportunity to intervene before tissue injury occurs. RECENT FINDINGS Various noninvasive technologies have been used assessing the microcirculation in hemodialysis patients at rest. Some technologies have also been applied during hemodialysis studying the effects of treatment on the microcirculation. Despite the approach used, results are consistent. Hemodialysis patients have impaired microcirculations with treatment adding additional stress to inadequately regulated vascular beds. Utility/practicality/clinical relevance vary significantly between methodologies. SUMMARY Intradialytic monitoring of the microcirculation can provide additional insights into a patient's individual response to treatment. However, this valuable perspective has not been adopted into clinical practice. A microcirculatory view could provide a window of opportunity to enable a precision medicine approach to treatment delivery improving current woefully poor subjective and objective clinical outcomes.
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7
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Janssen BGH, Zhang YM, Kosik I, Akbari A, McIntyre CW. Intravital microscopic observation of the microvasculature during hemodialysis in healthy rats. Sci Rep 2022; 12:191. [PMID: 34996931 PMCID: PMC8741960 DOI: 10.1038/s41598-021-03681-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/08/2021] [Indexed: 11/09/2022] Open
Abstract
Hemodialysis (HD) provides life-saving treatment for kidney failure. Patient mortality is extremely high, with cardiovascular disease (CVD) being the leading cause of death. This results from both a high underlying burden of cardiovascular disease, as well as additional physiological stress from the HD procedure itself. Clinical observations indicate that HD is associated with microvascular dysfunction (MD), underlining the need for a fundamental pathophysiological assessment of the microcirculatory consequences of HD. We therefore successfully developed an experimental small animal model, that allows for a simultaneous real-time assessment of the microvasculature. Using in-house built ultra-low surface area dialyzers and miniaturized extracorporeal circuit, we successfully dialyzed male Wistar Kyoto rats and combined this with a simultaneous intravital microscopic observation of the EDL microvasculature. Our results show that even in healthy animals, a euvolemic HD procedure can induce a significant systemic hemodynamic disturbance and induce disruption of microvascular perfusion (as evidence by a reduction in the proportion of the observed microcirculation receiving blood flow). This study, using a new small animal hemodialysis model, has allowed direct demonstration that microvascular blood flow in tissue in skeletal muscle is acutely reduced during HD, potentially in concert with other microvascular beds. It shows that preclinical small animal models can be used to further investigate HD-induced ischemic organ injury and allow rapid throughput of putative interventions directed at reducing HD-induced multi-organ ischemic injury.
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Affiliation(s)
- B G H Janssen
- Department of Medical Biophysics, Western University, London, ON, Canada.
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada.
- Kidney Clinical Research Unit (KCRU), London Health Sciences Centre, 800 Commissioners Rd. East, London, ON, N6C 6B5, Canada.
| | - Y M Zhang
- Department of Medical Biophysics, Western University, London, ON, Canada
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
- Trauma Research Centre, Fourth Medical Center of the Chinese PLA General Hospital, Beijing, 100048, People's Republic of China
- Intensive Care Unit, Tianjin Nankai Hospital, Tianjin, 300100, People's Republic of China
| | - I Kosik
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
- Imaging Program, Lawson Health Research Institute, St. Joseph's Health Care, London, ON, Canada
| | - A Akbari
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
- Robarts Research Institute, Western University, London, ON, Canada
| | - C W McIntyre
- Department of Medical Biophysics, Western University, London, ON, Canada
- Kidney Clinical Research Unit, Lawson Health Research Institute, London, ON, Canada
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Gusev E, Solomatina L, Zhuravleva Y, Sarapultsev A. The Pathogenesis of End-Stage Renal Disease from the Standpoint of the Theory of General Pathological Processes of Inflammation. Int J Mol Sci 2021; 22:ijms222111453. [PMID: 34768884 PMCID: PMC8584056 DOI: 10.3390/ijms222111453] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 12/14/2022] Open
Abstract
Chronic kidney disease can progress to end-stage chronic renal disease (ESRD), which requires the use of replacement therapy (dialysis or kidney transplant) in life-threatening conditions. In ESRD, irreversible changes in the kidneys are associated with systemic changes of proinflammatory nature and dysfunctions of internal organs, skeletal muscles, and integumentary tissues. The common components of ESRD pathogenesis, regardless of the initial nosology, are (1) local (in the kidneys) and systemic chronic low-grade inflammation (ChLGI) as a risk factor for diabetic kidney disease and its progression to ESRD, (2) inflammation of the classical type characteristic of primary and secondary autoimmune glomerulonephritis and infectious recurrent pyelonephritis, as well as immune reactions in kidney allograft rejection, and (3) chronic systemic inflammation (ChSI), pathogenetically characterized by latent microcirculatory disorders and manifestations of paracoagulation. The development of ChSI is closely associated with programmed hemodialysis in ESRD, as well as with the systemic autoimmune process. Consideration of ESRD pathogenesis from the standpoint of the theory of general pathological processes opens up the scope not only for particular but also for universal approaches to conducting pathogenetic therapies and diagnosing and predicting systemic complications in severe nephropathies.
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9
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Williams J, Gilchrist M, Strain WD, Fraser D, Shore A. An exploratory study of the relationship between systemic microcirculatory function and small solute transport in incident peritoneal dialysis patients. Perit Dial Int 2021; 42:513-521. [PMID: 34587842 DOI: 10.1177/08968608211047332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The peritoneal capillary endothelium is widely considered to be the most influential structure in dictating the rate of small solute transport (SST) during peritoneal dialysis (PD). PD patients are at significant risk of systemic microcirculatory dysfunction. The relationship between peritoneal and systemic microcirculations in patients new to PD has not been well studied. We hypothesised that for patients on PD for less than 6 months, dysfunction in the systemic microcirculation would be reflected in the rate of SST. METHODS We recruited 29 patients to a cross-sectional, observational study. Rate of SST was measured using a standard peritoneal equilibration test. Laser Doppler Flowmetry was used to measure response to physical and pharmacological challenge (post-occlusive hyperaemic response and iontophoretic application of vasodilators) in the cutaneous microcirculation. Sidestream Darkfield imaging was used to assess sublingual microvascular density, flow and endothelial barrier properties. RESULTS We found no moderate or strong correlations between any of the measures of systemic microcirculatory function and rate of SST or albumin clearance. There was however a significant correlation between dialysate interleukin-6 concentrations and both SST (rs = 0.758 p ≤ 0.0001) and albumin clearance (rs = 0.53, p = 0.01). CONCLUSIONS In this study, systemic microvascular dysfunction did not significantly influence the rate of SST even early in patients PD careers. In conclusion, this study demonstrates that intraperitoneal factors particularly inflammation have a far greater impact on rate of SST than systemic factors.
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Affiliation(s)
- Jennifer Williams
- Diabetes and Vascular Medicine Research Centre, NIHR Exeter Clinical Research Facility, University of Exeter College of Medicine and Health, UK
| | - Mark Gilchrist
- Diabetes and Vascular Medicine Research Centre, NIHR Exeter Clinical Research Facility, University of Exeter College of Medicine and Health, UK
| | - William David Strain
- Diabetes and Vascular Medicine Research Centre, NIHR Exeter Clinical Research Facility, University of Exeter College of Medicine and Health, UK
| | | | - Angela Shore
- Diabetes and Vascular Medicine Research Centre, NIHR Exeter Clinical Research Facility, University of Exeter College of Medicine and Health, UK
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Mahmoud O, El-Sakka M, Janssen BGH. Two-step machine learning method for the rapid analysis of microvascular flow in intravital video microscopy. Sci Rep 2021; 11:10047. [PMID: 33976293 PMCID: PMC8113514 DOI: 10.1038/s41598-021-89469-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 04/23/2021] [Indexed: 11/29/2022] Open
Abstract
Microvascular blood flow is crucial for tissue and organ function and is often severely affected by diseases. Therefore, investigating the microvasculature under different pathological circumstances is essential to understand the role of the microcirculation in health and sickness. Microvascular blood flow is generally investigated with Intravital Video Microscopy (IVM), and the captured images are stored on a computer for later off-line analysis. The analysis of these images is a manual and challenging process, evaluating experiments very time consuming and susceptible to human error. Since more advanced digital cameras are used in IVM, the experimental data volume will also increase significantly. This study presents a new two-step image processing algorithm that uses a trained Convolutional Neural Network (CNN) to functionally analyze IVM microscopic images without the need for manual analysis. While the first step uses a modified vessel segmentation algorithm to extract the location of vessel-like structures, the second step uses a 3D-CNN to assess whether the vessel-like structures have blood flowing in it or not. We demonstrate that our two-step algorithm can efficiently analyze IVM image data with high accuracy (83%). To our knowledge, this is the first application of machine learning for the functional analysis of microvascular blood flow in vivo.
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Affiliation(s)
- Ossama Mahmoud
- Department of Computer Sciences, Western University, London, ON, N6A 3K7, Canada
| | - Mahmoud El-Sakka
- Department of Computer Sciences, Western University, London, ON, N6A 3K7, Canada
| | - Barry G H Janssen
- Department of Medical Biophysics, Western University, London, ON, N6A 3K7, Canada.
- Centre for Critical Illness Research (CCIR), Lawson Health Research Institute, London, ON, N6C 6B5, Canada.
- Kidney Clinical Research Unit (KCRU), Lawson Health Research Institute, London, ON, N6C 6B5, Canada.
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11
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Early-life EV-A71 infection augments allergen-induced airway inflammation in asthma through trained macrophage immunity. Cell Mol Immunol 2021; 18:472-483. [PMID: 33441966 PMCID: PMC8027667 DOI: 10.1038/s41423-020-00621-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
Virus-induced asthma is prevalent among children, but its underlying mechanisms are unclear. Accumulated evidence indicates that early-life respiratory virus infection increases susceptibility to allergic asthma. Nonetheless, the relationship between systemic virus infections, such as enterovirus infection, and the ensuing effects on allergic asthma development is unknown. Early-life enterovirus infection was correlated with higher risks of allergic diseases in children. Adult mice exhibited exacerbated mite allergen-induced airway inflammation following recovery from EV-A71 infection in the neonatal period. Bone marrow-derived macrophages (BMDMs) from recovered EV-A71-infected mice showed sustained innate immune memory (trained immunity) that could drive naïve T helper cells toward Th2 and Th17 cell differentiation when in contact with mites. Adoptive transfer of EV-A71-trained BMDMs induced augmented allergic inflammation in naïve recipient mice, which was inhibited by 2-deoxy-D-glucose (2-DG) pretreatment, suggesting that trained macrophages following enterovirus infection are crucial in the progression of allergic asthma later in life.
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12
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Kooman JP, Stenvinkel P, Shiels PG, Feelisch M, Canaud B, Kotanko P. The oxygen cascade in patients treated with hemodialysis and native high-altitude dwellers: lessons from extreme physiology to benefit patients with end-stage renal disease. Am J Physiol Renal Physiol 2020; 320:F249-F261. [PMID: 33356957 DOI: 10.1152/ajprenal.00540.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Patients treated with hemodialysis (HD) repeatedly undergo intradialytic low arterial oxygen saturation and low central venous oxygen saturation, reflecting an imbalance between upper body systemic oxygen supply and demand, which are associated with increased mortality. Abnormalities along the entire oxygen cascade, with impaired diffusive and convective oxygen transport, contribute to the reduced tissue oxygen supply. HD treatment impairs pulmonary gas exchange and reduces ventilatory drive, whereas ultrafiltration can reduce tissue perfusion due to a decline in cardiac output. In addition to these factors, capillary rarefaction and reduced mitochondrial efficacy can further affect the balance between cellular oxygen supply and demand. Whereas it has been convincingly demonstrated that a reduced perfusion of heart and brain during HD contributes to organ damage, the significance of systemic hypoxia remains uncertain, although it may contribute to oxidative stress, systemic inflammation, and accelerated senescence. These abnormalities along the oxygen cascade of patients treated with HD appear to be diametrically opposite to the situation in Tibetan highlanders and Sherpa, whose physiology adapted to the inescapable hypobaric hypoxia of their living environment over many generations. Their adaptation includes pulmonary, vascular, and metabolic alterations with enhanced capillary density, nitric oxide production, and mitochondrial efficacy without oxidative stress. Improving the tissue oxygen supply in patients treated with HD depends primarily on preventing hemodynamic instability by increasing dialysis time/frequency or prescribing cool dialysis. Whether dietary or pharmacological interventions, such as the administration of L-arginine, fermented food, nitrate, nuclear factor erythroid 2-related factor 2 agonists, or prolyl hydroxylase 2 inhibitors, improve clinical outcome in patients treated with HD warrants future research.
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Affiliation(s)
- Jeroen P Kooman
- Division of Nephrology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Peter Stenvinkel
- Division of Renal Medicine, Department of Clinical Science Technology and Intervention, Karolinska Institutet, Stockholm, Sweden
| | - Paul G Shiels
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Martin Feelisch
- Clinical and Experimental Sciences and Integrative Physiology and Critical Illness Group, Faculty of Medicine, Southampton General Hospital and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Bernard Canaud
- Montpellier University, School of Medicine, Montpellier, France & Global Medical Office, Fresenius Medical Care, Bad Homburg, Germany
| | - Peter Kotanko
- Renal Research Institute, New York, New York.,Icahn School of Medicine at Mount Sinai, New York, New York
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13
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Possenti L, Di Gregorio S, Casagrande G, Costantino ML, Rancati T, Zunino P. A global sensitivity analysis approach applied to a multiscale model of microvascular flow. Comput Methods Biomech Biomed Engin 2020; 23:1215-1224. [DOI: 10.1080/10255842.2020.1793964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- L. Possenti
- LaBS, Department of Chemistry, Materials and Chemical Engineering ’Giulio Natta’, Politecnico di Milano, Milan, Italy
- Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - S. Di Gregorio
- MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy
| | - G. Casagrande
- LaBS, Department of Chemistry, Materials and Chemical Engineering ’Giulio Natta’, Politecnico di Milano, Milan, Italy
| | - M. L. Costantino
- LaBS, Department of Chemistry, Materials and Chemical Engineering ’Giulio Natta’, Politecnico di Milano, Milan, Italy
| | - T. Rancati
- Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - P. Zunino
- MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy
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14
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Williams J, Gilchrist M, Strain D, Fraser D, Shore A. The systemic microcirculation in dialysis populations. Microcirculation 2020; 27:e12613. [PMID: 32065681 DOI: 10.1111/micc.12613] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/08/2020] [Accepted: 02/14/2020] [Indexed: 12/17/2022]
Abstract
In a rapidly expanding population of patients with chronic kidney disease, including 2 million people requiring renal replacement therapy, cardiovascular mortality is 15 times greater than the general population. In addition to traditional cardiovascular risk factors, more poorly defined risks related to uremia and its treatments appear to contribute to this exaggerated risk. In this context, the microcirculation may play an important early role in cardiovascular disease associated with chronic kidney disease. Experimentally, the uremic environment and dialysis have been linked to multiple pathways causing microvascular dysfunction. Coronary microvascular dysfunction is reflected in remote and more easily studied vascular beds such as the skin. There is increasing evidence for a correlation between systemic microvascular dysfunction and adverse cardiovascular outcomes. Systemic microcirculatory changes have not been extensively investigated across the spectrum of chronic kidney disease. Recent advances in non-invasive techniques studying the microcirculation in vivo in man are increasing the data available particularly in patients on hemodialysis. Here, we review current knowledge of the systemic microcirculation in dialysis populations, explore whether non-invasive techniques to study its function could be used to detect early stage cardiovascular disease, address challenges faced in studying this patient cohort and identify potential future avenues for research.
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Affiliation(s)
- Jennifer Williams
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.,NIHR Exeter Clinical Research Facility, Royal Devon and Exeter Foundation NHS Trust, Exeter, UK
| | - Mark Gilchrist
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.,NIHR Exeter Clinical Research Facility, Royal Devon and Exeter Foundation NHS Trust, Exeter, UK
| | - David Strain
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.,NIHR Exeter Clinical Research Facility, Royal Devon and Exeter Foundation NHS Trust, Exeter, UK
| | - Donald Fraser
- Wales Kidney Research Unit, Cardiff University, Cardiff, UK
| | - Angela Shore
- Diabetes and Vascular Medicine Research Centre, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.,NIHR Exeter Clinical Research Facility, Royal Devon and Exeter Foundation NHS Trust, Exeter, UK
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15
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Guven G, Hilty MP, Ince C. Microcirculation: Physiology, Pathophysiology, and Clinical Application. Blood Purif 2019; 49:143-150. [PMID: 31851980 DOI: 10.1159/000503775] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 09/28/2019] [Indexed: 12/17/2022]
Abstract
This paper briefly reviews the physiological components of the microcirculation, focusing on its function in homeostasis and its central function in the realization of oxygen transport to tissue cells. Its pivotal role in the understanding of circulatory compromise in states of shock and renal compromise is discussed. Our introduction of hand-held vital microscopes (HVM) to clinical medicine has revealed the importance of the microcirculation as a central target organ in states of critical illness and inadequate response to therapy. Technical and methodological developments have been made in hardware and in software including our recent introduction and validation of automatic analysis software called MicroTools, which now allows point-of-care use of HVM imaging at the bedside for instant availability of functional microcirculatory parameters needed for microcirculatory targeted resuscitation procedures to be a reality.
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Affiliation(s)
- Goksel Guven
- Department of Intensive Care, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Matthias P Hilty
- Department of Intensive Care, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Can Ince
- Department of Intensive Care, Erasmus MC, University Medical Center, Rotterdam, The Netherlands,
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16
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Arinze NV, Gregory A, Francis JM, Farber A, Chitalia VC. Unique aspects of peripheral artery disease in patients with chronic kidney disease. Vasc Med 2019; 24:251-260. [PMID: 30823859 DOI: 10.1177/1358863x18824654] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Peripheral artery disease (PAD) represents a major health care burden. Despite the advent of screening and interventional procedures, the long-term clinical outcomes remain suboptimal, especially in patients with chronic kidney disease (CKD). While CKD and PAD share common predisposing factors, emerging studies indicate that their co-existence is not merely an association; instead, CKD represents a strong, independent risk factor for PAD. These findings implicate CKD-specific mediators of PAD that remain incompletely understood. Moreover, there is a need to understand the mechanisms underlying poor outcomes after interventions for PAD in CKD. This review discusses unique clinical aspects of PAD in patients with CKD, including high prevalence and worse outcomes after vascular interventions and the influence of renal allograft transplantation. In doing so, it also highlights underappreciated aspects of PAD in patients with CKD, such as disparities in revascularization and higher peri-procedural mortality. While previous reviews have discussed general mechanisms of PAD pathogenesis, focusing on PAD in CKD, this review underscores a need to probe for CKD-specific pathogenic pathways that may unravel novel biomarkers and therapeutic targets in PAD and ultimately improve the risk stratification and management of patients with CKD and PAD.
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Affiliation(s)
- Nkiruka V Arinze
- 1 Division of Vascular and Endovascular Surgery, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA.,2 Renal Section, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
| | | | - Jean M Francis
- 2 Renal Section, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
| | - Alik Farber
- 1 Division of Vascular and Endovascular Surgery, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
| | - Vipul C Chitalia
- 2 Renal Section, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA.,4 Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.,5 Veterans Affairs Boston Healthcare System, Boston, MA, USA
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