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Soroush A, Dunn JF. A Hypoxia-Inflammation Cycle and Multiple Sclerosis: Mechanisms and Therapeutic Implications. Curr Treat Options Neurol 2024; 27:6. [PMID: 39569339 PMCID: PMC11573864 DOI: 10.1007/s11940-024-00816-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2024] [Indexed: 11/22/2024]
Abstract
Purpose of Review Multiple sclerosis (MS) is a complex neurodegenerative disease characterized by inflammation, demyelination, and neurodegeneration. Significant hypoxia exists in brain of people with MS (pwMS), likely contributing to inflammatory, neurodegenerative, and vascular impairments. In this review, we explore the concept of a negative feedback loop between hypoxia and inflammation, discussing its potential role in disease progression based on evidence of hypoxia, and its implications for therapeutic targets. Recent Findings In the experimental autoimmune encephalomyelitis (EAE) model, hypoxia has been detected in gray matter (GM) using histological stains, susceptibility MRI and implanted oxygen sensitive probes. In pwMS, hypoxia has been quantified using near-infrared spectroscopy (NIRS) to measure cortical tissue oxygen saturation (StO2), as well as through blood-based biomarkers such as Glucose Transporter-1 (GLUT-1). We outline the potential for the hypoxia-inflammation cycle to drive tissue damage even in the absence of plaques. Inflammation can drive hypoxia through blood-brain barrier (BBB) disruption and edema, mitochondrial dysfunction, oxidative stress, vessel blockage and vascular abnormalities. The hypoxia can, in turn, drive more inflammation. Summary The hypoxia-inflammation cycle could exacerbate neuroinflammation and disease progression. We explore therapeutic approaches that target this cycle, providing information about potential treatments in MS. There are many therapeutic approaches that could block this cycle, including inhibiting hypoxia-inducible factor 1-α (HIF-1α), blocking cell adhesion or using vasodilators or oxygen, which could reduce either inflammation or hypoxia. This review highlights the potential significance of the hypoxia-inflammation pathway in MS and suggests strategies to break the cycle. Such treatments could improve quality of life or reduce rates of progression.
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Affiliation(s)
- Ateyeh Soroush
- Department of Neuroscience, University of Calgary, Calgary, Alberta Canada
- Hotchkiss Brain Institute (HBI), University of Calgary, Calgary, Alberta Canada
- Experimental Imaging Center (EIC), Cal Wenzel Precision Health Building (CWPH Building) University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4 Canada
| | - Jeff F Dunn
- Hotchkiss Brain Institute (HBI), University of Calgary, Calgary, Alberta Canada
- Department of Radiology, University of Calgary, Calgary, Alberta Canada
- Experimental Imaging Center (EIC), Cal Wenzel Precision Health Building (CWPH Building) University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4 Canada
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2
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Hayden MR. A Closer Look at the Perivascular Unit in the Development of Enlarged Perivascular Spaces in Obesity, Metabolic Syndrome, and Type 2 Diabetes Mellitus. Biomedicines 2024; 12:96. [PMID: 38255202 PMCID: PMC10813073 DOI: 10.3390/biomedicines12010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
The recently described perivascular unit (PVU) resides immediately adjacent to the true capillary neurovascular unit (NVU) in the postcapillary venule and contains the normal-benign perivascular spaces (PVS) and pathological enlarged perivascular spaces (EPVS). The PVS are important in that they have recently been identified to be the construct and the conduit responsible for the delivery of metabolic waste from the interstitial fluid to the ventricular cerebrospinal fluid for disposal into the systemic circulation, termed the glymphatic system. Importantly, the outermost boundary of the PVS is lined by protoplasmic perivascular astrocyte endfeet (pvACef) that communicate with regional neurons. As compared to the well-recognized and described neurovascular unit (NVU) and NVU coupling, the PVU is less well understood and remains an emerging concept. The primary focus of this narrative review is to compare the similarities and differences between these two units and discuss each of their structural and functional relationships and how they relate not only to brain homeostasis but also how they may relate to the development of multiple clinical neurological disease states and specifically how they may relate to obesity, metabolic syndrome, and type 2 diabetes mellitus. Additionally, the concept and importance of a perisynaptic astrocyte coupling to the neuronal synapses with pre- and postsynaptic neurons will also be considered as a perisynaptic unit to provide for the creation of the information transfer in the brain via synaptic transmission and brain homeostasis. Multiple electron microscopic images and illustrations will be utilized in order to help explain these complex units.
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Affiliation(s)
- Melvin R Hayden
- Department of Internal Medicine, Endocrinology Diabetes and Metabolism, Diabetes and Cardiovascular Disease Center, University of Missouri School of Medicine, One Hospital Drive, Columbia, MO 65211, USA
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3
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Novel non-stimulants rescue hyperactive phenotype in an adgrl3.1 mutant zebrafish model of ADHD. Neuropsychopharmacology 2022:10.1038/s41386-022-01505-z. [PMID: 36400921 PMCID: PMC10267219 DOI: 10.1038/s41386-022-01505-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022]
Abstract
ADHD is a highly prevalent neurodevelopmental disorder. The first-line therapeutic for ADHD, methylphenidate, can cause serious side effects including weight loss, insomnia, and hypertension. Therefore, the development of non-stimulant-based therapeutics has been prioritized. However, many of these also cause other effects, most notably somnolence. Here, we have used a uniquely powerful genetic model and unbiased drug screen to identify novel ADHD non-stimulant therapeutics. We first found that adgrl3.1 null (adgrl3.1-/-) zebrafish larvae showed a robust hyperactive phenotype. Although the hyperactivity was rescued by three ADHD non-stimulant therapeutics, all interfered significantly with sleep. Second, we used wild-type zebrafish larvae to characterize a simple behavioral phenotype generated by atomoxetine and screened the 1200 compound Prestwick Chemical Library® for a matching behavioral profile resulting in 67 hits. These hits were re-assayed in the adgrl3.1-/-. Using the previously identified non-stimulants as a positive control, we identified four compounds that matched the effect of atomoxetine: aceclofenac, amlodipine, doxazosin, and moxonidine. We additionally demonstrated cognitive effects of moxonidine in mice using a T-maze spontaneous alternation task. Moxonidine, has high affinity for imidazoline 1 receptors. We, therefore, assayed a pure imidazoline 1 agonist, LNP599, which generated an effect closely matching other non-stimulant ADHD therapeutics suggesting a role for this receptor system in ADHD. In summary, we introduce a genetic model of ADHD in zebrafish and identify five putative therapeutics. The findings offer a novel tool for understanding the neural circuits of ADHD, suggest a novel mechanism for its etiology, and identify novel therapeutics.
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Virgen-Carrillo CA, de Los Ríos DLH, Torres KR, Moreno AGM. Diagnostic Criteria for Metabolic Syndrome in Diet-Induced Rodent Models: A Systematic Review. Curr Diabetes Rev 2021; 17:e140421192834. [PMID: 33855947 DOI: 10.2174/1573399817666210414103730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/14/2021] [Accepted: 02/09/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Thousands of publications in recent years have addressed the induction of metabolic syndrome (MetS) in rodents. However, the criteria and the reference values for diagnosing this disease have not been defined. OBJECTIVE Our main objective was to carry out a systematic review to gather evidence about the criteria for biochemical and anthropometric parameters in which scientific studies have relied on to report that rats developed MetS from a previous dietary manipulation. METHODS We compiled characteristics and findings of diet-induced MetS with high-fat, high-carbohydrate, high-fat/high-carbohydrates, and cafeteria diet from PubMed and Science Direct databases published in the last 5 years. RESULTS The results on the principal determinants for the syndrome, published in the reviewed articles, were chosen to propose reference values in the rat models of food induction. CONCLUSION The values obtained will serve as reference cut-of points in the development of the disease; in addition, the compilation of data will be useful in planning and executing research protocols in animal models.
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Affiliation(s)
- Carmen Alejandrina Virgen-Carrillo
- Instituto de Investigaciones en Comportamiento Alimentario y Nutrición, Centro Universitario del Sur, Universidad de Guadalajara, Jalisco, Mexico
| | - Diana Laura Hernández de Los Ríos
- Instituto de Investigaciones en Comportamiento Alimentario y Nutrición, Centro Universitario del Sur, Universidad de Guadalajara, Jalisco, Mexico
| | - Karina Ruíz Torres
- Instituto de Investigaciones en Comportamiento Alimentario y Nutrición, Centro Universitario del Sur, Universidad de Guadalajara, Jalisco, Mexico
| | - Alma Gabriela Martínez Moreno
- Instituto de Investigaciones en Comportamiento Alimentario y Nutrición, Centro Universitario del Sur, Universidad de Guadalajara, Jalisco, Mexico
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5
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Capillary Rarefaction in Obesity and Metabolic Diseases-Organ-Specificity and Possible Mechanisms. Cells 2020; 9:cells9122683. [PMID: 33327460 PMCID: PMC7764934 DOI: 10.3390/cells9122683] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/02/2020] [Accepted: 12/10/2020] [Indexed: 12/11/2022] Open
Abstract
Obesity and its comorbidities like diabetes, hypertension and other cardiovascular disorders are the leading causes of death and disability worldwide. Metabolic diseases cause vascular dysfunction and loss of capillaries termed capillary rarefaction. Interestingly, obesity seems to affect capillary beds in an organ-specific manner, causing morphological and functional changes in some tissues but not in others. Accordingly, treatment strategies targeting capillary rarefaction result in distinct outcomes depending on the organ. In recent years, organ-specific vasculature and endothelial heterogeneity have been in the spotlight in the field of vascular biology since specialized vascular systems have been shown to contribute to organ function by secreting varying autocrine and paracrine factors and by providing niches for stem cells. This review summarizes the recent literature covering studies on organ-specific capillary rarefaction observed in obesity and metabolic diseases and explores the underlying mechanisms, with multiple modes of action proposed. It also provides a glimpse of the reported therapeutic perspectives targeting capillary rarefaction. Further studies should address the reasons for such organ-specificity of capillary rarefaction, investigate strategies for its prevention and reversibility and examine potential signaling pathways that can be exploited to target it.
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Nisimura LM, Bousquet P, Muccillo F, Tibirica E, Garzoni LR. Tyrosine hydroxylase and β2-adrenergic receptor expression in leukocytes of spontaneously hypertensive rats: putative peripheral markers of central sympathetic activity. ACTA ACUST UNITED AC 2020; 53:e9615. [PMID: 33146287 PMCID: PMC7643929 DOI: 10.1590/1414-431x20209615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/27/2020] [Indexed: 11/21/2022]
Abstract
The sympathetic nervous system (SNS) plays a fundamental role in the pathophysiology of cardiovascular diseases, including primary arterial hypertension. In this study, we aimed to investigate whether the expression of the rate-limiting enzyme in catecholamine synthesis, tyrosine hydroxylase (TH), and the β2-adrenergic receptor (β2-AR) in immune cells from peripheral blood, reflect central SNS activity in spontaneously hypertensive rats (SHR). TH expression in the lower brainstem and adrenal glands and β2-AR expression in the lower brainstem were analyzed by western blot analyses. In the leukocytes, TH and β2-AR expression was evaluated by flow cytometry before and after chronic treatment with the centrally-acting sympathoinhibitory drug clonidine. Western blot analyses showed increased TH and β2-AR expression in the lower brainstem and increased TH in adrenal glands from SHR compared to normotensive Wistar Kyoto rats (WKY). Lower brainstem from SHR treated with clonidine presented reduced TH and β2-AR levels, and adrenal glands had decreased TH expression compared to SHR treated with vehicle. Flow cytometry showed that the percentage of leukocytes that express β2-AR is higher in SHR than in WKY. However, the percentage of leukocytes that expressed TH was higher in WKY than in SHR. Moreover, chronic treatment with clonidine normalized the levels of TH and β2-AR in leukocytes from SHR to similar levels of those of WKY. Our study demonstrated that the percentage of leukocytes expressing TH and β2-AR was altered in arterial hypertension and can be modulated by central sympathetic inhibition with clonidine treatment.
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Affiliation(s)
- L M Nisimura
- Laboratório de Inovações em Terapias, Ensino e Bioprodutos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.,Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - P Bousquet
- Department of Pharmacology, Faculty of Medicine, University of Strasbourg, Strasbourg, France
| | - F Muccillo
- Instituto Nacional de Cardiologia, Ministério da Saúde, Rio de Janeiro, RJ, Brasil
| | - E Tibirica
- Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.,Instituto Nacional de Cardiologia, Ministério da Saúde, Rio de Janeiro, RJ, Brasil
| | - L R Garzoni
- Laboratório de Inovações em Terapias, Ensino e Bioprodutos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
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7
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Govindpani K, McNamara LG, Smith NR, Vinnakota C, Waldvogel HJ, Faull RL, Kwakowsky A. Vascular Dysfunction in Alzheimer's Disease: A Prelude to the Pathological Process or a Consequence of It? J Clin Med 2019; 8:E651. [PMID: 31083442 PMCID: PMC6571853 DOI: 10.3390/jcm8050651] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/29/2019] [Accepted: 05/06/2019] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia. Despite decades of research following several theoretical and clinical lines, all existing treatments for the disorder are purely symptomatic. AD research has traditionally been focused on neuronal and glial dysfunction. Although there is a wealth of evidence pointing to a significant vascular component in the disease, this angle has been relatively poorly explored. In this review, we consider the various aspects of vascular dysfunction in AD, which has a significant impact on brain metabolism and homeostasis and the clearance of β-amyloid and other toxic metabolites. This may potentially precede the onset of the hallmark pathophysiological and cognitive symptoms of the disease. Pathological changes in vessel haemodynamics, angiogenesis, vascular cell function, vascular coverage, blood-brain barrier permeability and immune cell migration may be related to amyloid toxicity, oxidative stress and apolipoprotein E (APOE) genotype. These vascular deficits may in turn contribute to parenchymal amyloid deposition, neurotoxicity, glial activation and metabolic dysfunction in multiple cell types. A vicious feedback cycle ensues, with progressively worsening neuronal and vascular pathology through the course of the disease. Thus, a better appreciation for the importance of vascular dysfunction in AD may open new avenues for research and therapy.
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Affiliation(s)
- Karan Govindpani
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Laura G McNamara
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Nicholas R Smith
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Chitra Vinnakota
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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8
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Nascimento AR, Gomes F, Machado MV, Gonçalves-de-Albuquerque C, Bousquet P, Tibiriçá E. I 1-imidazoline receptor-mediated cardiovascular and metabolic effects in high-fat diet-induced metabolic syndrome in rats. Auton Neurosci 2018; 217:18-25. [PMID: 30704971 DOI: 10.1016/j.autneu.2018.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/09/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVES The objective of this study was to investigate the effects of a new I1-imidazoline receptor-selective pyrroline compound on the hemodynamic, metabolic and microvascular alterations in a high-fat diet (HFD)-induced model of metabolic syndrome in rats. METHODS In total, twenty adult male Wistar rats were fed a high-fat diet (HFD, n = 20) for 20 weeks. Thereafter, the rats received a new pyrroline compound selective for I1-imidazoline receptors (LNP599; 10 mg/kg/day) or vehicle (n = 10/group) orally by gavage for 4 weeks. Functional microcirculation was assessed using intravital video microscopy, and structural microcirculation was evaluated using histochemical analysis. RESULTS LNP599 induced concomitant reductions in the SBP, HR and plasma catecholamine levels. The animals treated with this new antihypertensive compound also presented an improvement in body weight and the metabolic parameters related to metabolic syndrome, such as the glucose and lipid profiles. These effects were accompanied by a reversal of the functional and structural capillary rarefaction in the skeletal muscle. CONCLUSIONS The modulation of the sympathetic nervous system by a selective agonist for I1-imidazoline receptors improves the hemodynamic and metabolic parameters in an experimental model of metabolic syndrome. LNP599 can also contribute to the restoration of microcirculatory parameters.
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Affiliation(s)
- Alessandro R Nascimento
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil; Faculty of Medicine of the University of Strasbourg, Strasbourg, France.
| | - Fabiana Gomes
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
| | - Marcus V Machado
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
| | | | - Pascal Bousquet
- Faculty of Medicine of the University of Strasbourg, Strasbourg, France
| | - Eduardo Tibiriçá
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
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9
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Iwamoto E, Bock JM, Casey DP. Blunted shear-mediated dilation of the internal but not common carotid artery in response to lower body negative pressure. J Appl Physiol (1985) 2018; 124:1326-1332. [DOI: 10.1152/japplphysiol.01011.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Shear-mediated dilation in peripheral conduit arteries is blunted with sympathetic nervous system (SNS) activation; however, the effect of SNS activation on shear-mediated dilation in carotid arteries is unknown. We hypothesized that SNS activation reduces shear-mediated dilation in common and internal carotid arteries (CCA and ICA, respectively), and this attenuation is greater in the ICA compared with the CCA. Shear-mediated dilation in the CCA and ICA were measured in nine healthy men (24 ± 1 yr) with and without SNS activation. Shear-mediated dilation was induced by 3 min of hypercapnia (end‐tidal partial pressure of carbon dioxide +10 mmHg from individual baseline); SNS activity was increased with lower body negative pressure (LBNP; −20 mmHg). CCA and ICA measurements were made using Doppler ultrasound during hypercapnia with (LBNP) or without (Control) SNS activation. LBNP trials began with 5 min of LBNP with subjects breathing hypercapnic gas during the final 3 min. Shear-mediated dilation was calculated as the percent rise in peak diameter from baseline diameter. Sympathetic activation attenuated shear-mediated dilation in the ICA (Control vs. LBNP, 5.5 ± 0.7 vs. 1.8 ± 0.4%, P < 0.01), but not in the CCA (5.1 ± 1.2 vs. 4.2 ± 1.0%, P = 0.31). Moreover, absolute reduction in shear-mediated dilation via SNS activation was greater in the ICA than the CCA (−3.6 ± 0.7 vs. −0.9 ± 0.8%, P = 0.02). Our data indicate that shear-mediated dilation is attenuated during LBNP to a greater extent in the ICA compared with the CCA. These results potentially provide insight into the role of SNS activation on cerebral perfusion, as the ICA is a key supplier of blood to the brain. NEW & NOTEWORTHY We explored the effect of acute sympathetic nervous system (SNS) activation on shear-mediated dilation in the common and internal carotid arteries (CCA and ICA, respectively) in young healthy men. Our data demonstrate that hypercapnia-induced vasodilation of the ICA is attenuated during lower body negative pressure to a greater extent than the CCA. These data may provide novel information related to the role of SNS activation on cerebral perfusion in humans.
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Affiliation(s)
- Erika Iwamoto
- Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
- School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Joshua M. Bock
- Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Darren P. Casey
- Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
- Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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10
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Freitas F, Estato V, Reis P, Castro-Faria-Neto HC, Carvalho V, Torres R, Lessa MA, Tibirica E. Acute simvastatin treatment restores cerebral functional capillary density and attenuates angiotensin II-induced microcirculatory changes in a model of primary hypertension. Microcirculation 2017; 24. [DOI: 10.1111/micc.12416] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/25/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Felipe Freitas
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
| | - Vanessa Estato
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
| | - Patricia Reis
- Laboratory of Immunopharmacology; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
| | - Hugo C. Castro-Faria-Neto
- Laboratory of Immunopharmacology; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
- Estácio de Sá University; Rio de Janeiro Brazil
| | - Vinícius Carvalho
- Laboratory of Inflammation; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
| | - Rafael Torres
- Laboratory of Inflammation; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
| | - Marcos A. Lessa
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
| | - Eduardo Tibirica
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute; FIOCRUZ; Rio de Janeiro RJ Brazil
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11
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Machado MV, Vieira AB, da Conceição FG, Nascimento AR, da Nóbrega ACL, Tibirica E. Exercise training dose differentially alters muscle and heart capillary density and metabolic functions in an obese rat with metabolic syndrome. Exp Physiol 2017; 102:1716-1728. [PMID: 28921743 DOI: 10.1113/ep086416] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 09/12/2017] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Regular exercise is recommended as a non-pharmacological approach for the prevention and treatment of metabolic syndrome. However, the impact of different combinations of intensity, duration and frequency of exercise on metabolic syndrome and microvascular density has not been reported. What is the main finding and its importance? We provide evidence on the impact of aerobic exercise dose on metabolic and microvascular alterations in an experimental model of metabolic syndrome induced by high-fat diet. We found that the exercise frequency and duration were the main factors affecting anthropometric and metabolic parameters and microvascular density in the skeletal muscle. Exercise intensity was related only to microvascular density in the heart. We evaluated the effect of the frequency, duration and intensity of exercise training on metabolic parameters and structural capillary density in obese rats with metabolic syndrome. Wistar-Kyoto rats were fed either a standard commercial diet (CON) or a high-fat diet (HFD). Animals that received the HFD were randomly separated into either a sedentary (SED) group or eight different exercise groups that varied according to the frequency, duration and intensity of training. After 12 weeks of aerobic exercise training, the body composition, aerobic capacity, haemodynamic variables, metabolic parameters and capillary density in the heart and skeletal muscle were evaluated. All the exercise training groups showed reduced resting systolic blood pressure and heart rate and normalized fasting glucose. The minimal amount of exercise (90 min per week) produced little effect on metabolic syndrome parameters. A moderate amount of exercise (150 min per week) was required to reduce body weight and improve capillary density. However, only the high amount of exercise (300 min per week) significantly reduced the amount of body fat depots. The three-way ANOVA showed a main effect of exercise frequency and duration for the improvement of metabolic syndrome and capillary density in skeletal muscle. Exercise intensity was a main factor in reversing microvascular rarefaction in the heart.
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Affiliation(s)
- Marcus Vinicius Machado
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil.,Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Aline Bomfim Vieira
- Laboratory of Inflammation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
| | | | | | | | - Eduardo Tibirica
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
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12
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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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