Microcirculation最新文献

{"title":"Isolated Fragments of Intact Microvessels: Tissue Vascularization, Modeling, and Therapeutics","authors":"Hannah A. Strobel,&nbsp;Sarah M. Moss,&nbsp;James B. Hoying","doi":"10.1111/micc.12852","DOIUrl":"10.1111/micc.12852","url":null,"abstract":"<div>\u0000 \u0000 <p>The microvasculature is integral to nearly every tissue in the body, providing not only perfusion to and from the tissue, but also homing sites for immune cells, cellular niches for tissue dynamics, and cooperative interactions with other tissue elements. As a microtissue itself, the microvasculature is a composite of multiple cell types exquisitely organized into structures (individual vessel segments and extensive vessel networks) capable of considerable dynamics and plasticity. Consequently, it has been challenging to include a functional microvasculature in assembled or fabricated tissues. Isolated fragments of intact microvessels, which retain the cellular composition and structures of native microvessels, are proving effective in a variety of vascularization applications including tissue in vitro disease modeling, vascular biology, mechanistic discovery, and tissue prevascularization in regenerative therapeutics and grafting. In this review, we will discuss the importance of recapitulating native tissue biology and the successful vascularization applications of isolated microvessels.</p>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140595034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increased Angio-Derived Index of Microcirculatory Resistance Within a Timeframe of 30–60 days After COVID-19 Infection","authors":"Lei Dong,&nbsp;Ritai Na,&nbsp;Lang Peng,&nbsp;Xinye Xu","doi":"10.1111/micc.12851","DOIUrl":"10.1111/micc.12851","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Objectives</h3>\u0000 \u0000 <p>Chest pain is a relatively long-term symptom that commonly occurs in patients who have contracted COVID-19. The reasons for these symptoms remain unclear, with coronary microvascular dysfunction (CMD) emerging as a potential factor. This study aimed to assess the presence of CMD in these patients by measuring the angio-derived index of microcirculatory resistance (AMR).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this cross-sectional case–control study, patients who had chest pain and a history of COVID-19 infection within the preceding 30 to 60 days were included. The control subjects were patients without COVID-19. Demographic, clinical, and echocardiographic data were recorded. Angiographic images were collected for AMR analysis through an angioplus quantitative flow ratio measurement system. Propensity score matching (PSM) was performed to match the two groups. Multivariate logistic regression was used to examine the association between COVID-19 incidence and the increase in AMR (AMR &gt; 285 mmHg*s/m) after correction for other confounders.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>After PSM, there were 58 patients in each group (the mean age was 66.3 ± 9.04 years, and 55.2% were men). The average time between the onset of COVID-19 infection and patient presentation at the hospital for coronary angiography was 41 ± 9.5 days. Moreover, there was no significant difference in the quantitative flow ratio between the two groups. Patients with COVID-19 had a greater mean AMR (295 vs. 266, <i>p</i> = 0.002). Multivariate logistic regression analysis revealed that COVID-19 (OR = 3.32, 95% CI = 1.50–7.60, <i>p</i> = 0.004) was significantly associated with an increase in AMR.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Long-term COVID-19 patients who experience chest pain without evidence of myocardial ischemia exhibit an increase in AMR, and CMD may be one of the reasons for this increase. COVID-19 is an independent risk factor for an increase in AMR.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140143763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract","authors":"","doi":"10.1111/micc.12846","DOIUrl":"10.1111/micc.12846","url":null,"abstract":"","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140049846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling cerebrovascular responses to assess the impact of the collateral circulation following middle cerebral artery occlusion","authors":"Erin Zhao,&nbsp;Jared Barber,&nbsp;Shomita S. Mathew-Steiner,&nbsp;Savita Khanna,&nbsp;Chandan K. Sen,&nbsp;Julia Arciero","doi":"10.1111/micc.12849","DOIUrl":"10.1111/micc.12849","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>An improved understanding of the role of the leptomeningeal collateral circulation in blood flow compensation following middle cerebral artery (MCA) occlusion can contribute to more effective treatment development for ischemic stroke. The present study introduces a model of the cerebral circulation to predict cerebral blood flow and tissue oxygenation following MCA occlusion.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The model incorporates flow regulation mechanisms based on changes in pressure, shear stress, and metabolic demand. Oxygen saturation in cerebral vessels and tissue is calculated using a Krogh cylinder model. The model is used to assess the effects of changes in oxygen demand and arterial pressure on cerebral blood flow and oxygenation after MCA occlusion.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>An increase from five to 11 leptomeningeal collateral vessels was shown to increase the oxygen saturation in the region distal to the occlusion by nearly 100%. Post-occlusion, the model also predicted a loss of autoregulation and a decrease in flow to the ischemic territory as oxygen demand was increased; these results were consistent with data from experiments that induced cerebral ischemia.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study highlights the importance of leptomeningeal collaterals following MCA occlusion and reinforces the idea that lower oxygen demand and higher arterial pressure improve conditions of flow and oxygenation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/micc.12849","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139729967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sex-specific microvascular and hemodynamic responses to passive limb heating in young adults","authors":"Miranda K. Traylor,&nbsp;Genevieve B. Batman,&nbsp;Kylie N. Sears,&nbsp;Kyndall V. Ransom,&nbsp;Shane M. Hammer,&nbsp;Joshua L. Keller","doi":"10.1111/micc.12848","DOIUrl":"10.1111/micc.12848","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>We examined sex-specific microvascular reactivity and hemodynamic responses under conditions of augmented resting blood flow induced by passive heating compared to normal blood flow.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Thirty-eight adults (19 females) completed a vascular occlusion test (VOT) on two occasions preceded by rest with or without passive heating in a randomized, counterbalanced order. Skeletal muscle tissue oxygenation (StO₂, %) was assessed with near-infrared spectroscopy (NIRS), and the rate of desaturation and resaturation as well as maximal StO₂ (StO_2max) and prolonged hypersaturation (area under the curve, StO_2AUC) were quantified. Before the VOT, brachial artery blood flow (BABF), vascular conductance, and relative BABF (BABF normalized to forearm lean mass) were determined. Sex × condition ANOVAs were used. A <i>p</i>-value ≤.05 was considered statistically significant.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Twenty minutes of heating increased BABF compared to the control (102.9 ± 28.3 vs. 36.0 ± 20.9 mL min⁻¹; <i>p</i> &lt; .01). Males demonstrated greater BABF than females (91.9 ± 34.0 vs. 47.0 ± 19.1 mL min⁻¹; <i>p</i> &lt; .01). There was no sex difference in normalized BABF. There were no significant interactions for NIRS-VOT outcomes, but heat did increase the rate of desaturation (−0.140 ± 0.02 vs. −0.119 ± 0.03% s⁻¹; <i>p</i> &lt; .01), whereas regardless of condition, males exhibited greater rates of resaturation and StO_2max than females.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These results suggest that blood flow is not the primary factor causing sex differences in NIRS-VOT outcomes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139570710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of stalling events on microcirculatory hemodynamics in the aged brain","authors":"Mohammad Jamshidi,&nbsp;Thomas Ventimiglia,&nbsp;Patrice Sudres,&nbsp;Cong Zhang,&nbsp;Frédéric Lesage,&nbsp;William Rooney,&nbsp;Daniel Schwartz,&nbsp;Andreas A. Linninger","doi":"10.1111/micc.12845","DOIUrl":"10.1111/micc.12845","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>The role of cerebral microvasculature in cognitive dysfunction can be investigated by identifying the impact of blood flow on cortical tissue oxygenation. In this paper, the impact of capillary stalls on microcirculatory characteristics such as flow and hematocrit (Ht) in the cortical angioarchitecture is studied.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using a deterministic mathematical model to simulate blood flow in a realistic mouse cortex, hemodynamics parameters, including pressure, flow, vessel diameter-adjustable hematocrit, and transit time are calculated as a function of stalling events.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Using a non-linear plasma skimming model, it is observed that Ht increases in the penetrating arteries from the pial vessels as a function of cortical depth. The incidence of stalling on Ht distribution along the blood network vessels shows reduction of RBCs around the tissue near occlusion sites and decreased Ht concentration downstream from the blockage points. Moreover, upstream of the occlusion, there is a noticeable increase of the Ht, leading to larger flow resistance due to higher blood viscosity. We predicted marked changes in transit time behavior due to stalls which match trends observed in mice in vivo.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These changes to blood cell quantity and quality may be implicated in the development of Alzheimer's disease and contribute to the course of the illness.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/micc.12845","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139542533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Retinal vascular dynamics: A window for observing an irregular heartbeat. A case report","authors":"Rebekka Heitmar,&nbsp;Paulus Kirchhoff,&nbsp;Andrew Blann,&nbsp;Konstantin Kotliar","doi":"10.1111/micc.12844","DOIUrl":"10.1111/micc.12844","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>We aimed to characterize several aspects of retinal vascular dynamics in a patient with arrythmia in order to elicit additional diagnostic information on microvascular dysfunction.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A 68-year-old male patient with arrythmia and an age- and gender-matched control subject underwent ocular examination including dynamic retinal vessel assessment with flicker light provocation. Retinal vessel diameters were measured continuously following a standard protocol (IMEDOS Systems, Jena, Germany). The data were evaluated using methods of signal analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Retinal vessel response following flicker provocation as well as local structural and functional behavior of retinal vessels were comparable between both individuals. The arrhythmia case demonstrated irregular arterial and venous heart rate (HR) pulsation with an average frequency of 1 Hz. Moreover, the case showed a higher magnitude and larger periods of low-frequency retinal vessel oscillations as well as lower periodicity of both HR pulsations and low-frequency vasomotions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Besides numerical examination of irregular HR pulsations in case of arrhythmia, from the direct noninvasive assessment of retinal vessel dynamics one can derive more detailed information on microvascular function including the whole spectrum of retinal arterial and venous pulsations and vasomotions. This may have implications for health screening not limited to atrial fibrillation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/micc.12844","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139495613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Men with nonobstructive coronary disease have higher burden of ischemic heart disease detected by cardiopulmonary exercise test","authors":"Siyuan Li,&nbsp;Yifang Yuan,&nbsp;Lanting Zhao,&nbsp;Tingting Lv,&nbsp;Fei She,&nbsp;Fang Liu,&nbsp;Yajun Xue,&nbsp;Boda Zhou,&nbsp;Ying Xie,&nbsp;Yu Geng,&nbsp;Ping Zhang","doi":"10.1111/micc.12841","DOIUrl":"10.1111/micc.12841","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Nonobstructive coronary artery disease (NOCAD), characterized by the presence of myocardial ischemic symptoms and signs without obstructive coronaries, is a common clinical condition, but it is less well understood. Few studies have analyzed the gender differences in inducible myocardial ischemia assessed by cardiopulmonary exercise test (CPET) in NOCAD.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We conducted a study of 289 NOCAD patients (mean age 60, 56% women) with ischemic symptoms and confirmed ⫹50% coronaries stenoses by coronary angiography who underwent symptom-limited CPET. We assessed ischemic response using predicted % peak VO₂, O₂ pulse trajectory, and exercise ECG test.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Men with NOCAD had significantly lower predicted % peak VO₂ (62% vs. 73%), higher proportions of flattening pattern (16% vs. 2%), and downward patterns of O₂ pulse trajectory (2% vs. 0%) (<i>p</i> &lt; .0001) compared with women. In contrast, women with NOCAD had a higher prevalence of shallow patterns of O₂ pulse trajectory (21% vs. 6%, <i>p</i> &lt; .0001). Men with NOCAD had a higher risk ischemic profile (medium risk: 63% vs. 54%, high risk: 18% vs. 4%, <i>p</i> &lt; .0001). After adjustment, men with NOCAD had significantly lower predicted % peak VO₂ (β −27.4, 95% CI −30.74 to −24.07), higher risk for abnormal O₂ pulse trajectories (OR 4.21, 95% CI 1.93 to 9.19), and myocardial ischemia risk per CPET parameters (OR 3.14, 95% CI 1.78 to 5.54) (<i>p</i> &lt; .0001).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Men with NOCAD had a higher risk profile for ischemic heart disease per CPET. Therefore, they should receive rigorous management and follow-up to prevent cardiovascular events.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139481070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coronary microvascular dysfunction as assessed by multimodal diagnostic imaging in patients with hypertrophic cardiomyopathy is related to the severity of cardiac dysfunction","authors":"Tien Vuong Tran,&nbsp;Loic Djaileb,&nbsp;Laurent Riou,&nbsp;Lea Ruez Lantuejoul,&nbsp;Joris Giai,&nbsp;Gilles Barone-Rochette","doi":"10.1111/micc.12843","DOIUrl":"10.1111/micc.12843","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>Coronary microvascular dysfunction (CMD) plays a major role in hypertrophic cardiomyopathy (HCM) physiopathology but its assessment in clinical practice remains a challenge. Nowadays, innovations in invasive and noninvasive coronary evaluation using multimodal imaging provide options for the diagnosis of CMD. The objective of the present study was to investigate if new multimodal imaging diagnosis of CMD could detect HCM patients with more impaired cardiac function by left atrioventricular coupling index (LACI).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods and Results</h3>\u0000 \u0000 <p>A total of 32 consecutive patients with a confirmed diagnosis of HCM (62 ± 13 years, 62% men) were prospectively screened for CMD using a multimodal imaging method. LACI was assessed by cardiovascular magnetic resonance imaging. Fifteen (47%) patients had CMD by multimodal imaging method. Patients with CMD presented a significantly higher LACI (48.5 ± 25.4 vs. 32.5 ± 10.6, <i>p</i> = .03). A multivariate logistic regression analysis demonstrated that CMD was independently associated with LACI (OR = 1.069, 95% CI 1.00–1.135, <i>p</i> = .03).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Multimodal imaging diagnosis of CMD is applicable to HCM patients and is associated with more impaired cardiac function.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139087468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitric oxide-mediated vasodilation in human bone","authors":"Adina E. Draghici,&nbsp;Matthew R. Ely,&nbsp;Jason W. Hamner,&nbsp;J. Andrew Taylor","doi":"10.1111/micc.12842","DOIUrl":"10.1111/micc.12842","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>Regulation of blood flow to bone is critical but poorly understood, particularly in humans. This study aims to determine whether nitric oxide (NO), a major regulator of vascular tone to other tissues, contributes also to the regulation of blood flow to bone.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In young healthy adults (<i>n</i> = 16, 8F, 8M), we characterized NO-mediated vasodilation in the tibia in response to sublingual nitroglycerin and contrasted it to lower leg. Blood flow responses were assessed in supine individuals by continuously measuring tibial total hemoglobin (tHb) via near-infrared spectroscopy and lower leg blood flow (LBF) as popliteal flow velocity via Doppler ultrasound in the same leg.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>LBF increased by Δ9.73 ± 0.66 cm/s and peaked 4.4 min after NO administration and declined slowly but remained elevated (Δ3.63 ± 0.60 cm/s) at 10 min. In contrast, time to peak response was longer and smaller in magnitude in the tibia as tHb increased Δ2.08 ± 0.22 μM and peaked 5.3 min after NO administration and declined quickly but remained elevated (Δ0.87±0.22 μM) at 10 min (<i>p</i> = .01).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>In young adults, the tibial vasculature demonstrates robust NO-mediated vasodilation, but tHb is delayed and diminishes faster compared to LBF, predominately reflective of skeletal muscle responses. Thus, NO-mediated vasodilation in bone may be characteristically different from other vascular beds.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18459,"journal":{"name":"Microcirculation","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138830408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}