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Menon NJ, Halvorson BD, Alimorad GH, Frisbee JC, Lizotte DJ, Ward AD, Goldman D, Chantler PD, Frisbee SJ. A novel vascular health index: Using data analytics and population health to facilitate mechanistic modeling of microvascular status. Front Physiol 2022; 13:1071813. [PMID: 36561210 PMCID: PMC9763931 DOI: 10.3389/fphys.2022.1071813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022] Open
Abstract
The study of vascular function across conditions has been an intensive area of investigation for many years. While these efforts have revealed many factors contributing to vascular health, challenges remain for integrating results across research groups, animal models, and experimental conditions to understand integrated vascular function. As such, the insights attained in clinical/population research from linking datasets, have not been fully realized in the basic sciences, thus frustrating advanced analytics and complex modeling. To achieve comparable advances, we must address the conceptual challenge of defining/measuring integrated vascular function and the technical challenge of combining data across conditions, models, and groups. Here, we describe an approach to establish and validate a composite metric of vascular function by comparing parameters of vascular function in metabolic disease (the obese Zucker rat) to the same parameters in age-matched, "healthy" conditions, resulting in a common outcome measure which we term the vascular health index (VHI). VHI allows for the integration of datasets, thus expanding sample size and permitting advanced modeling to gain insight into the development of peripheral and cerebral vascular dysfunction. Markers of vascular reactivity, vascular wall mechanics, and microvascular network density are integrated in the VHI. We provide a detailed presentation of the development of the VHI and provide multiple measures to assess face, content, criterion, and discriminant validity of the metric. Our results demonstrate how the VHI captures multiple indices of dysfunction in the skeletal muscle and cerebral vasculature with metabolic disease and provide context for an integrated understanding of vascular health under challenged conditions.
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Affiliation(s)
- Nithin J. Menon
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Brayden D. Halvorson
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Gabrielle H. Alimorad
- Department of Epidemiology and Biostatistics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Jefferson C. Frisbee
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Daniel J. Lizotte
- Department of Epidemiology and Biostatistics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada,Department of Computer Science, Faculty of Science, University of Western Ontario, London, ON, Canada,Lawson Health Research Institute, London, ON, Canada
| | - Aaron D. Ward
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada,Lawson Health Research Institute, London, ON, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Paul D. Chantler
- Department of Human Performance-Exercise Physiology, School of Medicine, West Virginia University, Morgantown, WV, United States
| | - Stephanie J. Frisbee
- Department of Epidemiology and Biostatistics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada,Lawson Health Research Institute, London, ON, Canada,Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada,*Correspondence: Stephanie J. Frisbee,
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Oral Glucose Load and Human Cutaneous Microcirculation: An Insight into Flowmotion Assessed by Wavelet Transform. BIOLOGY 2021; 10:biology10100953. [PMID: 34681052 PMCID: PMC8533385 DOI: 10.3390/biology10100953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/31/2021] [Accepted: 09/10/2021] [Indexed: 01/10/2023]
Abstract
Simple Summary There is increasing evidence to suggest that microcirculation becomes dysfunctional earlier than large blood vessels or the heart in several diseases. In diabetes mellitus, a disease characterized by chronic hyperglycemia, microvascular impairment is well-established; on the contrary, the effect of acute hyperglycemia in microcirculation remains unclarified. Our aim was to investigate the microvascular effect of an oral glucose load (OGL) using laser Doppler flowmetry (LDF) as a perfusion quantification technique, coupled with wavelet transform (WT) to perform a spectral decomposition of the LDF signal. On two distinct occasions (pre-load and post-load), sixteen healthy subjects drank either a standard glucose solution or water. Perfusion was assessed by LDF and WT while resting and during post-occlusive reactive hyperemia (PORH), evoked by a transient three-min occlusion of the brachial artery, in the forearm and the finger pulp. The OGL affected microcirculation in both sites compared to water, significantly blunting the PORH response in the forearm. The WT revealed significant differences in the cardiac and sympathetic components after OGL between the pre-load and post-load periods. These results suggest that an OGL induces a short-term subtle microvascular impairment, probably involving a modulation of the sympathetic nervous system. Abstract Microcirculation in vivo has been assessed using non-invasive technologies such as laser Doppler flowmetry (LDF). In contrast to chronic hyperglycemia, known to induce microvascular dysfunction, the effects of short-term elevations in blood glucose on microcirculation are controversial. We aimed to assess the impact of an oral glucose load (OGL) on the cutaneous microcirculation of healthy subjects, quantified by LDF and coupled with wavelet transform (WT) as an interpretation tool. On two separate occasions, sixteen subjects drank either a glucose solution (75 g in 250 mL water) or water (equal volume). LDF signals were obtained in two anatomical sites (forearm and finger pulp) before and after each load (pre-load and post-load, respectively), in resting conditions and during post-occlusive reactive hyperemia (PORH). The WT allowed decomposition of the LDF signals into their spectral components (cardiac, respiratory, myogenic, sympathetic, endothelial NO-dependent). The OGL blunted the PORH response in the forearm, which was not observed with the water load. Significant differences were found for the cardiac and sympathetic components in the glucose and water groups between the pre-load and post-load periods. These results suggest that an OGL induces a short-term subtle microvascular impairment, probably involving a modulation of the sympathetic nervous system.
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Chipperfield AJ, Thanaj M, Scorletti E, Byrne CD, Clough GF. Multi-domain analysis of microvascular flow motion dynamics in NAFLD. Microcirculation 2019; 26:e12538. [PMID: 30803094 DOI: 10.1111/micc.12538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/22/2019] [Accepted: 02/20/2019] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To determine whether analysis of microvascular network perfusion using complexity-based methods can discriminate between groups of individuals at an increased risk of developing CVD. METHODS Data were obtained from laser Doppler recordings of skin blood flux at the forearm in 50 participants with non-alcoholic fatty liver disease grouped for absence (n = 28) or presence (n = 14) of type 2 diabetes and use of calcium channel blocker medication (n = 8). Power spectral density was evaluated and Lempel-Ziv complexity determined to quantify signal information content at single and multiple time-scales to account for the different processes modulating network perfusion. RESULTS Complexity was associated with dilatory capacity and respiration and negatively with baseline blood flux and cardiac band power. The relationship between the modulators of flowmotion and complexity of blood flux is shown to change with time-scale improving discrimination between groups. Multiscale Lempel-Ziv achieved best classification accuracy of 86.1%. CONCLUSIONS Time and frequency domain measures alone are insufficient to discriminate between groups. As cardiovascular disease risk increases, the degree of complexity of the blood flux signal reduces, indicative of a reduced temporal activity and heterogeneous distribution of blood flow within the microvascular network sampled. Complexity-based methods, particularly multiscale variants, are shown to have good discriminatory capabilities.
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Affiliation(s)
- Andrew J Chipperfield
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
| | - Marjola Thanaj
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
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Obesity and inactivity, not hyperglycemia, cause exercise intolerance in individuals with type 2 diabetes: Solving the obesity and inactivity versus hyperglycemia causality dilemma. Med Hypotheses 2019; 123:110-114. [DOI: 10.1016/j.mehy.2019.01.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 01/15/2019] [Indexed: 12/29/2022]
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Breslin JW. Cellular cross talk, inflammatory signals, and enhanced microvascular permeability. Microcirculation 2018; 24. [PMID: 28295872 DOI: 10.1111/micc.12368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 01/24/2023]
Abstract
Microvascular leakage remains a significant clinical problem for which there is no specific therapeutic available. This Special Topics issue of the journal Microcirculation features reviews pertaining to the cellular and molecular mechanisms that control the integrity of the microvascular barrier. (Meegan et al., Microcirculation, 2017) summarize recent research findings about how neutrophil extracellular traps and how these can cause injury to the microvascular barrier.( Zhang et al. Microcirculation, 2017) highlight the microvascular response to advanced glycation end-products that are formed as part of the pathophysiology of diabetes mellitus. These ongoing investigations are helping to clarify the mechanisms by which endothelial cells receive information and integrate it to generate cellular responses that fine-tune barrier function. Better understanding of these mechanisms is needed for the rational development of therapeutic strategies to reduce excessive microvascular leakage.
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Affiliation(s)
- Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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Poitras VJ, Hudson RW, Tschakovsky ME. Exercise intolerance in Type 2 diabetes: is there a cardiovascular contribution? J Appl Physiol (1985) 2018; 124:1117-1139. [PMID: 29420147 DOI: 10.1152/japplphysiol.00070.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Physical activity is critically important for Type 2 diabetes management, yet adherence levels are poor. This might be partly due to disproportionate exercise intolerance. Submaximal exercise tolerance is highly sensitive to muscle oxygenation; impairments in exercising muscle oxygen delivery may contribute to exercise intolerance in Type 2 diabetes since there is considerable evidence for the existence of both cardiac and peripheral vascular dysfunction. While uncompromised cardiac output during submaximal exercise is consistently observed in Type 2 diabetes, it remains to be determined whether an elevated cardiac sympathetic afferent reflex could sympathetically restrain exercising muscle blood flow. Furthermore, while deficits in endothelial function are common in Type 2 diabetes and are often cited as impairing exercising muscle oxygen delivery, no direct evidence in exercise exists, and there are several other vasoregulatory mechanisms whose dysfunction could contribute. Finally, while there are findings of impaired oxygen delivery, conflicting evidence also exists. A definitive conclusion that Type 2 diabetes compromises exercising muscle oxygen delivery remains premature. We review these potentially dysfunctional mechanisms in terms of how they could impair oxygen delivery in exercise, evaluate the current literature on whether an oxygen delivery deficit is actually manifest, and correspondingly identify key directions for future research.
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Affiliation(s)
- Veronica J Poitras
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada.,Department of Physiology, Queen's University , Kingston, Ontario , Canada.,Children's Hospital of Eastern Ontario, Research Institute , Ottawa, Ontario , Canada
| | - Robert W Hudson
- Department of Medicine, Division of Endocrinology, Queen's University , Kingston, Ontario , Canada
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
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Frisbee JC. Obesity, insulin resistance, and microvascular adaptation. Microcirculation 2018; 24. [PMID: 27987530 DOI: 10.1111/micc.12346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 11/27/2022]
Abstract
Two of the primary risk factors for the progressive evolution of cardiovascular disease are obesity and impaired glycemic control-including both insulin resistance and overt type 2 diabetes mellitus, leading to increased research emphasis on these conditions, their mechanistic bases, and their health outcomes. This Special Topics Issue of the journal Microcirculation summarizes a symposium at the recent Joint Meeting of the American Physiological Society and the Physiological Society, held in Dublin, Ireland, on July 30, 2016. This symposium, "Adaptive outcomes of microvascular networks to obesity and type 2 diabetes mellitus/insulin resistance," presented four lectures, each of which addressed the larger issue from a different perspective.
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Affiliation(s)
- Jefferson C Frisbee
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
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Lemaster KA, Farid Z, Brock RW, Shrader CD, Goldman D, Jackson DN, Frisbee JC. Altered post-capillary and collecting venular reactivity in skeletal muscle with metabolic syndrome. J Physiol 2017; 595:5159-5174. [PMID: 28556909 DOI: 10.1113/jp274291] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 05/26/2017] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS With the development of the metabolic syndrome, both post-capillary and collecting venular dilator reactivity within the skeletal muscle of obese Zucker rats (OZR) is impaired. The impaired dilator reactivity in OZR reflects a loss in venular nitric oxide and PGI2 bioavailability, associated with the chronic elevation in oxidant stress. Additionally, with the impaired dilator responses, a modest increase in adrenergic constriction combined with an elevated thromboxane A2 production may contribute to impaired functional dilator and hyperaemic responses at the venular level. For the shift in skeletal muscle venular function with development of the metabolic syndrome, issues such as aggregate microvascular perfusion resistance, mass transport and exchange within with capillary networks, and fluid handling across the microcirculation are compelling avenues for future investigation. ABSTRACT While research into vascular outcomes of the metabolic syndrome has focused on arterial/arteriolar and capillary levels, investigation into venular function and how this impacts responses has received little attention. Using the in situ cremaster muscle of obese Zucker rats (OZR; with lean Zucker rats (LZR) as controls), we determined indices of venular function. At ∼17 weeks of age, skeletal muscle post-capillary venular density was reduced by ∼20% in LZR vs. OZR, although there was no evidence of remodelling of the venular wall. Venular tone at ∼25 μm (post-capillary) and ∼75 μm (collecting) diameter was elevated in OZR vs. LZR. Venular dilatation to acetylcholine was blunted in OZR vs. LZR due to increased oxidant stress-based loss of nitric oxide bioavailability (post-capillary) and increased α1 - (and α2 -) mediated constrictor tone (collecting). Venular constrictor responses in OZR were comparable to LZR for most stimuli, although constriction to α1 -adrenoreceptor stimulation was elevated. In response to field stimulation of the cremaster muscle (0.5, 1, 3 Hz), venular dilator and hyperaemic responses to lower frequencies were blunted in OZR, but responses at 3 Hz were similar between strains. Venous production of TxA2 was higher in OZR than LZR and significantly higher than PGI2 production in either following arachidonic acid challenge. These results suggest that multi-faceted alterations to skeletal muscle venular function in OZR may contribute to alterations in upstream capillary pressure profiles and the transcapillary exchange of solutes and water under conditions of metabolic syndrome.
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Affiliation(s)
- Kent A Lemaster
- Department of Medical Biophysics, Transdisciplinary Program in Vascular Health, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Zahra Farid
- Department of Medical Biophysics, Transdisciplinary Program in Vascular Health, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Robert W Brock
- Departments of Physiology and Pharmacology, West Virginia University HSC, Morgantown, WV, USA
| | - Carl D Shrader
- Family Medicine, West Virginia University HSC, Morgantown, WV, USA
| | - Daniel Goldman
- Department of Medical Biophysics, Transdisciplinary Program in Vascular Health, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Dwayne N Jackson
- Department of Medical Biophysics, Transdisciplinary Program in Vascular Health, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Jefferson C Frisbee
- Department of Medical Biophysics, Transdisciplinary Program in Vascular Health, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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