Effects of age and smoking on endothelial function assessed by quantitative cardiovascular magnetic resonance in the peripheral and central vasculature

Leukocyte telomere length and mitochondrial DNA copy number associate with endothelial function in aging-related cardiovascular disease

Background

We investigated the association between leukocyte telomere length, mitochondrial DNA copy number, and endothelial function in patients with aging-related cardiovascular disease (CVD).

Methods

In total 430 patients with CVD and healthy persons were enrolled in the current study. Peripheral blood was drawn by routine venipuncture procedure. Plasma and peripheral blood mononuclear cells (PBMCs) were collected. Cell-free genomic DNA (cfDNA) and leukocytic genomic DNA (leuDNA) were extracted from plasma and PBMCs, respectively. Relative telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN) were analyzed using quantitative polymerase chain reaction. Endothelial function was evaluated by measuring flow-mediated dilation (FMD). The correlation between TL of cfDNA (cf-TL), mtDNA-CN of cfDNA (cf-mtDNA), TL of leuDNA (leu-TL), mtDNA-CN of leuDNA (leu-mtDNA), age, and FMD were analyzed based on Spearman's rank correlation. The association between cf-TL, cf-mtDNA, leu-TL, leu-mtDNA, age, gender, and FMD were explored using multiple linear regression analysis.

Results

cf-TL positively correlated with cf-mtDNA (r = 0.1834, P = 0.0273), and leu-TL positively correlated with leu-mtDNA (r = 0.1244, P = 0.0109). In addition, both leu-TL (r = 0.1489, P = 0.0022) and leu-mtDNA (r = 0.1929, P < 0.0001) positively correlated with FMD. In a multiple linear regression analysis model, both leu-TL (β = 0.229, P = 0.002) and leu-mtDNA (β = 0.198, P = 0.008) were positively associated with FMD. In contrast, age was inversely associated with FMD (β = -0.426, P < 0.0001).

Conclusion

TL positively correlates mtDNA-CN in both cfDNA and leuDNA. leu-TL and leu-mtDNA can be regarded as novel biomarkers of endothelial dysfunction.

Tobacco smoking and vascular biology and function: evidence from human studies

Tobacco cigarette smoking is among the most complex and least understood health risk factors. A deeper insight into the pathophysiological actions of smoking exposure is of special importance as smoking is a major cause of chronic non-communicable diseases, in particular of cardiovascular disease as well as risk factors such as atherosclerosis and arterial hypertension. It is well known that smoking exerts its negative effects on cardiovascular health through various interdependent pathophysiological actions including hemodynamic and autonomic alterations, oxidative stress, inflammation, endothelial dysfunction, thrombosis, and hyperlipidemia. Importantly, impaired vascular endothelial function is acknowledged as an early key event in the initiation and progression of smoking-induced atherosclerosis. Increasing evidence from human studies indicates that cigarette smoke exposure associates with a pathological state of the vascular endothelium mainly characterized by reduced vascular nitric oxide bioavailability due to increased vascular superoxide production. In the present overview, we provide compact evidence on the effects of tobacco cigarette smoke exposure on vascular biology and function in humans centered on main drivers of adverse cardiovascular effects including endothelial dysfunction, inflammation, and oxidative stress.

Impact of supervised exercise on skeletal muscle blood flow and vascular function measured with MRI in patients with peripheral artery disease

Supervised exercise is a common therapeutic intervention for patients with peripheral artery disease (PAD), however, the mechanism underlying the improvement in claudication symptomatology is not completely understood. The hypothesis that exercise improves microvascular blood flow is herein tested via temporally resolved magnetic resonance imaging (MRI) measurement of blood flow and oxygenation dynamics during reactive hyperemia in the leg with the lower ankle-brachial index. One hundred and forty-eight subjects with PAD were prospectively assigned to standard medical care or 3 mo of supervised exercise therapy. Before and after the intervention period, subjects performed a graded treadmill walking test, and MRI data were collected with Perfusion, Intravascular Venous Oxygen saturation, and T2* (PIVOT), a method that simultaneously quantifies microvascular perfusion, as well as relative oxygenation changes in skeletal muscle and venous oxygen saturation in a large draining vein. The 3-mo exercise intervention was associated with an improvement in peak walking time (64% greater in those randomized to the exercise group at follow-up, P < 0.001). Significant differences were not observed in the MRI measures between the subjects randomized to exercise therapy versus standard medical care based on an intention-to-treat analysis. However, the peak postischemia perfusion averaged across the leg between baseline and follow-up visits increased by 10% (P = 0.021) in participants that were adherent to the exercise protocol (completed >80% of prescribed exercise visits). In this cohort of adherent exercisers, there was no difference in the time to peak perfusion or oxygenation metrics, suggesting that there was no improvement in microvascular function nor changes in tissue metabolism in response to the 3-mo exercise intervention.NEW & NOTEWORTHY Supervised exercise interventions can improve symptomatology in patients with peripheral artery disease, but the underlying mechanism remains unclear. Here, MRI was used to evaluate perfusion, relative tissue oxygenation, and venous oxygen saturation in response to cuff-induced ischemia. Reactive hyperemia responses were measured before and after 3 mo of randomized supervised exercise therapy or standard medical care. Those participants who were adherent to the exercise regimen had a significant improvement in peak perfusion.

The Role of Circulating Lycopene in Low-Grade Chronic Inflammation: A Systematic Review of the Literature

BACKGROUND AND AIMS

In recent years, it has become clear that low-grade chronic inflammation is involved in the onset and progression of many non-communicable diseases. Many studies have investigated the association between inflammation and lycopene, however, results have been inconsistent. This systematic review aims to determine the impact of circulating lycopene on inflammation and to investigate the effect of consuming tomato products and/or lycopene supplements on markers of inflammation.

METHODS

Eligible studies, published before March 2020, were identified from PubMed, EBSCOhost and ScienceDirect. Human studies published in English, that evaluated the effect of circulating lycopene in relation to inflammation biomarkers were screened and included. Studies assessing lycopene intake or general intake of carotenoids/antioxidants without measuring circulating lycopene, as well as those not reporting inflammation biomarkers as outcomes, were excluded.

RESULTS

Out of 80 publications identified and screened, 35 met the inclusion criteria. Results from 18 cross-sectional studies suggest that lycopene levels are adversely affected during inflammation and homeostatic imbalance. Most of the 17 included intervention studies reported increased circulating lycopene levels after tomato/lycopene supplementation, but almost no changes in inflammation biomarkers were observed.

CONCLUSIONS

There is little evidence that increasing tomato intake or lycopene supplementation diminuates this inflammation. However, depletion of lycopene may be one of the first signs of low-grade inflammation. The available data thereby imply that it is beneficial to consume lycopene-rich foods occasionally to stay healthy and keep circulating lycopene at a basal level.

Evaluation of Vascular Reactivity of Maternal Vascular Adaptations of Pregnancy With Quantitative MRI: Pilot Study

BACKGROUND

Abnormal maternal vascular function during pregnancy stemming from systemic endothelial dysfunction (EDF) has a central role in the pathophysiology of preeclampsia (PE).

PURPOSE

To utilize quantitative MRI to investigate changes in physiological measures of vascular reactivity during normal pregnancy, and to explore EDF associated with preeclampsia.

STUDY TYPE

Prospective.

POPULATION

Healthy pregnant (HP) (n = 14, mean GA = 26 ± 7 weeks) and nonpregnant women (NP; n = 14); newly postpartum (PP <48 hours) women with severe PE (PP-PE; n = 4) and normotensive pregnancy (PP-HP; n = 5).

FIELD STRENGTH/SEQUENCE

1.5T/3T. RF spoiled multiecho gradient-recalled echo, 1D phase-contrast MRI, time-of-flight.

ASSESSMENT

The micro- and macrovascular function (vasodilatory capacity of arterioles and conduit arteries, respectively) of the femoral vascular bed was evaluated with MRI-based venous oximetry, arterial velocimetry, and luminal flow-mediated dilation quantification, during cuff-induced reactive hyperemia. Aortic arch pulse-wave velocity (aPWV) was quantified to assess arterial stiffness using an ungated 1D technique.

STATISTICAL TESTS

Two-tailed unpaired t-tests were performed to address our two, primary a priori comparisons, HP vs. NP, and PP-PE vs. PP-HP. Given the pilot nature of this study, adjustments for multiple comparisons were not performed.

RESULTS

In HP, microvascular function was attenuated compared to NP by a significant increase in the washout time (10 ± 2 vs. 8 ± 2 sec; P < 0.05) and reduced upslope (2.1 ± 0.5 vs. 3.2 ± 0.8%HbO₂ /s; P < 0.05), time of forward flow (28 ± 5 vs. 33 ± 6 sec, P < 0.05), and hyperemic index (11 ± 3 vs. 16 ± 4 cm/s² ; P < 0.05), but luminal flow-mediated dilatation (FMD_L )was comparable between HP and NP. PP-PE exhibited significant vascular dysfunction compared to PP-HP, as evidenced by differences in upslope (2.2 ± 0.6 vs. 1.3 ± 0.2%HbO₂ /s, P < 0.05), overshoot (16 ± 5 vs. 7 ± 3%HbO₂ , P < 0.05), time of forward flow (28 ± 6 vs. 15 ± 7 s, P < 0.05), and aPWV (7 ± 1 vs. 8 ± 1 m/s, P < 0.05).

DATA CONCLUSION

Attenuated vascular reactivity during pregnancy suggests that the systemic vasodilatory state partially depletes nitric oxide bioavailability. Preliminary data support the potential for MRI to identify vascular dysfunction in vivo that underlies PE. Level of Evidence 2 Technical Efficacy Stage 1 J. MAGN. RESON. IMAGING 2021;53:447-455.

New Insights From MRI and Cell Biology Into the Acute Vascular-Metabolic Implications of Electronic Cigarette Vaping

The popularity of electronic cigarettes (e-cigs) has grown at a startling rate since their introduction to the United States market in 2007, with sales expected to outpace tobacco products within a decade. Spurring this trend has been the notion that e-cigs are a safer alternative to tobacco-based cigarettes. However, the long-term health impacts of e-cigs are not yet known. Quantitative magnetic resonance imaging (MRI) approaches, developed in the authors’ laboratory, provide conclusive evidence of acute deleterious effects of e-cig aerosol inhalation in the absence of nicotine in tobacco-naïve subjects. Among the pathophysiologic effects observed are transient impairment of endothelial function, vascular reactivity, and oxygen metabolism. The culprits of this response are currently not fully understood but are likely due to an immune reaction caused by the aerosol containing thermal breakdown products of the e-liquid, including radicals and organic aldehydes, with particle concentrations similar to those emitted by conventional cigarettes. The acute effects observed following a single vaping episode persist for 1–3 h before subsiding to baseline and are paralleled by build-up of biological markers. Sparse data exist on long-term effects of vaping, and it is likely that repeated regular exposure to e-cig aerosol during vaping will lead to chronic conditions since there would be no return to baseline conditions as in the case of an isolated vaping episode. This brief review aims to highlight the potential of pairing MRI, with its extraordinary sensitivity to structure, physiology and metabolism at the holistic level, with biologic investigations targeting serum and cellular markers of inflammation and oxidative stress. Such a multi-modal framework should allow interpretation of the impact of e-cigarette vaping on vascular health at the organ level in the context of the underlying biological alterations. Applications of this approach to the study of other lifestyle-initiated pathologies including hypertension, hypercholesterolemia, and metabolic syndrome are indicated.

Quantitative and Dynamic MRI Measures of Peripheral Vascular Function

The endothelium regulates and mediates vascular homeostasis, allowing for dynamic changes of blood flow in response to mechanical and chemical stimuli. Endothelial dysfunction underlies many diseases and is purported to be the earliest pathologic change in the progression of atherosclerotic disease. Peripheral vascular function can be interrogated by measuring the response kinetics following induced ischemia or exercise. In the presence of endothelial dysfunction, there is a blunting and delay of the hyperemic response, which can be measured non-invasively using a variety of quantitative magnetic resonance imaging (MRI) methods. In this review, we summarize recent developments in non-contrast, proton MRI for dynamic quantification of blood flow and oxygenation. Methodologic description is provided for: blood oxygenation-level dependent (BOLD) signal that reflect combined effect of blood flow and capillary bed oxygen content; arterial spin labeling (ASL) for quantification of regional perfusion; phase contrast (PC) to quantify arterial flow waveforms and macrovascular blood flow velocity and rate; high-resolution MRI for luminal flow-mediated dilation; and dynamic MR oximetry to quantify oxygen saturation. Overall, results suggest that these dynamic and quantitative MRI methods can detect endothelial dysfunction both in the presence of overt cardiovascular disease (such as in patients with peripheral artery disease), as well as in sub-clinical settings (i.e., in chronic smokers, non-smokers exposed to e-cigarette aerosol, and as a function of age). Thus far, these tools have been relegated to the realm of research, used as biomarkers of disease progression and therapeutic response. With proper validation, MRI-measures of vascular function may ultimately be used to complement the standard clinical workup, providing additional insight into the optimal treatment strategy and evaluation of treatment efficacy.

Radiologic, Pathologic, Clinical, and Physiologic Findings of Electronic Cigarette or Vaping Product Use-associated Lung Injury (EVALI): Evolving Knowledge and Remaining Questions

Proposed as a safer alternative to smoking, the use of electronic cigarettes has not proven to be innocuous. With numerous deaths, there is an increasing degree of public interest in understanding the symptoms, imaging appearances, causes of, and treatment of electronic cigarette or vaping product use-associated lung injury (EVALI). Patients with EVALI typically have a nonspecific clinical presentation characterized by a combination of respiratory, gastrointestinal, and constitutional symptoms. EVALI is a diagnosis of exclusion; the patient must elicit a history of recent vaping within 90 days, other etiologies must be eliminated, and chest imaging findings must be abnormal. Chest CT findings in EVALI most commonly show a pattern of acute lung injury on the spectrum of organizing pneumonia and diffuse alveolar damage. The pathologic pattern found depends on when in the evolution of the disease process the biopsy sample is taken. Other less common forms of lung injury, including acute eosinophilic pneumonia and diffuse alveolar hemorrhage, have also been reported. Radiologists and pathologists help play an important role in the evaluation of patients suspected of having EVALI. Accurate and rapid identification may decrease morbidity and mortality by allowing for aggressive clinical management and glucocorticoid administration, which have been shown to decrease the severity of lung injury in some patients. In this review, the authors summarize the current state of the art for the imaging and pathologic findings of this disorder and outline a few of the major questions that remain to be answered.

Personal NO2 and Volatile Organic Compounds Exposure Levels are Associated with Markers of Cardiovascular Risk in Women in the Cape Town Region of South Africa

Exposure to ambient NO2 and benzene, toluene ethyl-benzene and m+p- and o-xylenes (BTEX) is associated with adverse cardiovascular effects, but limited information is available on the effects of personal exposure to these compounds in South African populations. This 6-month follow-up study aims to determine 7-day personal ambient NO2 and BTEX exposure levels via compact passive diffusion samplers in female participants from Cape Town, and investigate whether exposure levels are associated with cardiovascular risk markers. Overall, the measured air pollutant exposure levels were lower compared to international standards. NO2 was positively associated with systolic and diastolic blood pressure (SBP and DBP), and inversely associated with the central retinal venular equivalent (CRVE) and mean baseline brachial artery diameter. o-xylene was associated with DBP and benzene was strongly associated with carotid intima media thickness (cIMT). Our findings showed that personal air pollution exposure, even at relatively low levels, was associated with several markers of cardiovascular risk in women residing in the Cape Town region.

Lycopene and Metabolic Syndrome: A Systematic Review of the Literature

Cardiometabolic risk factors increase the likelihood of cardiovascular disease development by 2-fold. Lycopene, a potent lipophilic antioxidant, may be able to mediate oxidative stress, a mechanism underpinning metabolic syndrome (MetS) and its risk factors. This is, to our knowledge, the first systematic review of the literature with the purpose of investigating the relation between circulating lycopene or dietary intake of lycopene and MetS as well as its risk factors. The review was conducted using PubMed and EBSCOhost databases with the search terms "lycopene" and "metabolic syndrome."  Inclusion criteria included human studies published in English in a scholarly, peer-reviewed journal and evaluation of lycopene in relation to ≥3 of the 5 MetS risk factors as defined by the National Cholesterol Education Program's Adult Treatment Panel III (ATP III) report. The process identified 11 studies, including 8 cross-sectional and 3 intervention studies. Cross-sectional studies were grouped into 3 categories, with several studies falling into >1 category, based on results reporting associations of lycopene with the prevalence and outcomes of MetS (5 studies), presence of ATP III risk factors (4 studies), and variables mediating lycopene's influence on MetS risk (3 studies). All studies in each category reported significant protective associations. Of the 3 intervention studies, all reported significant protective effects from a lycopene-rich beverage, despite varying doses and durations of intake. Although a protective relation between lycopene and MetS was generally supported, different MetS components appeared to be influenced by lycopene rather than demonstrating consistent improvement in a single component. Thus, additional research is needed to elucidate the mechanistic effects of lycopene on MetS, as well as to determine evidence-based recommendations concerning dose-durational effects of lycopene and MetS risk reduction. In conclusion, the evidence of lycopene's benefit exists such that lycopene status or lycopene consumption may be associated with favorable alterations to the components of MetS.

Review of Journal of Cardiovascular Magnetic Resonance (JCMR) 2015-2016 and transition of the JCMR office to Boston

The Journal of Cardiovascular Magnetic Resonance (JCMR) is the official publication of the Society for Cardiovascular Magnetic Resonance (SCMR). In 2016, the JCMR published 93 manuscripts, including 80 research papers, 6 reviews, 5 technical notes, 1 protocol, and 1 case report. The number of manuscripts published was similar to 2015 though with a 12% increase in manuscript submissions to an all-time high of 369. This reflects a decrease in the overall acceptance rate to <25% (excluding solicited reviews). The quality of submissions to JCMR continues to be high. The 2016 JCMR Impact Factor (which is published in June 2016 by Thomson Reuters) was steady at 5.601 (vs. 5.71 for 2015; as published in June 2016), which is the second highest impact factor ever recorded for JCMR. The 2016 impact factor means that the JCMR papers that were published in 2014 and 2015 were on-average cited 5.71 times in 2016.In accordance with Open-Access publishing of Biomed Central, the JCMR articles are published on-line in the order that they are accepted with no collating of the articles into sections or special thematic issues. For this reason, over the years, the Editors have felt that it is useful to annually summarize the publications into broad areas of interest or themes, so that readers can view areas of interest in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes with previously published JCMR papers to guide continuity of thought in the journal. In addition, I have elected to open this publication with information for the readership regarding the transition of the JCMR editorial office to the Beth Israel Deaconess Medical Center, Boston and the editorial process.Though there is an author publication charge (APC) associated with open-access to cover the publisher's expenses, this format provides a much wider distribution/availability of the author's work and greater manuscript citation. For SCMR members, there is a substantial discount in the APC. I hope that you will continue to send your high quality manuscripts to JCMR for consideration. Importantly, I also ask that you consider referencing recent JCMR publications in your submissions to the JCMR and elsewhere as these contribute to our impact factor. I also thank our dedicated Associate Editors, Guest Editors, and reviewers for their many efforts to ensure that the review process occurs in a timely and responsible manner and that the JCMR continues to be recognized as the leading publication in our field.

In vivo whole-blood T2 versus HbO2 calibration by modulating blood oxygenation level in the femoral vein through intermittent cuff occlusion

PURPOSE

To investigate the feasibility of estimating calibration constants (K and T_2o ) in vivo for converting whole-blood T₂ to blood hemoglobin oxygen saturation (HbO₂ ) according to the Luz-Meiboom model, 1/T2=1/T2o+K(1-HbO2)2, where K and T_2o are relaxivity and transverse relaxation time of fully saturated blood, respectively.

METHODS

A range of HbO₂ values was achieved in the superficial femoral vein with intermittent cuff occlusion in seven healthy adults (four males) to establish a calibration curve between blood T₂ and HbO₂ at 1.5T. HbO₂ was derived via MR susceptometry, a technique previously validated, and the transverse relaxation time was quantified with an optimized T₂ -prepared balanced steady-state free precession pulse sequence. To evaluate the accuracy of the in vivo calibration method, T₂ and HbO₂ were quantified in the superior sagittal sinus in six additional subjects and compared with susceptometry.

RESULTS

Two sets of gender-specific calibration constants were derived, one for each gender corresponding to hematocrits of 0.47 ± 0.02 for males and 0.38 ± 0.01 for females, yielding K/T_2o  = 41 Hz/260 ms and 26 Hz/280 ms, respectively. The in vivo calibration returned physiologically plausible superior sagittal sinus SvO₂ values (65 ± 5% HbO₂ ), and there was no significant difference between the results from the two methods (average difference -0.3% HbO₂ ).

CONCLUSION

The results show feasibility of performing in vivo calibration for converting whole-blood T₂ to HbO₂ . The proposed approach bypasses the involved and cumbersome processes associated with in vitro calibration. Magn Reson Med 79:2290-2296, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Simultaneous measurement of macro- and microvascular blood flow and oxygen saturation for quantification of muscle oxygen consumption

PURPOSE

To investigate the relationship between blood flow and oxygen consumption in skeletal muscle, a technique called "Velocity and Perfusion, Intravascular Venous Oxygen saturation and T2*" (vPIVOT) is presented. vPIVOT allows the quantification of feeding artery blood flow velocity, perfusion, draining vein oxygen saturation, and muscle T2*, all at 4-s temporal resolution. Together, the measurement of blood flow and oxygen extraction can yield muscle oxygen consumption ( V˙O2) via the Fick principle.

METHODS

In five subjects, vPIVOT-derived results were compared with those obtained from stand-alone sequences during separate ischemia-reperfusion paradigms to investigate the presence of measurement bias. Subsequently, in 10 subjects, vPIVOT was applied to assess muscle hemodynamics and V˙O2 following a bout of dynamic plantar flexion contractions.

RESULTS

From the ischemia-reperfusion paradigm, no significant differences were observed between data from vPIVOT and comparison sequences. After exercise, the macrovascular flow response reached a maximum 8 ± 3 s after relaxation; however, perfusion in the gastrocnemius muscle continued to rise for 101 ± 53 s. Peak V˙O2 calculated based on mass-normalized arterial blood flow or perfusion was 15.2 ± 6.7 mL O₂ /min/100 g or 6.0 ± 1.9 mL O₂ /min/100 g, respectively.

CONCLUSIONS

vPIVOT is a new method to measure blood flow and oxygen saturation, and therefore to quantify muscle oxygen consumption. Magn Reson Med 79:846-855, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Susceptibility-based time-resolved whole-organ and regional tissue oximetry

The magnetism of hemoglobin - being paramagnetic in its deoxy and diamagnetic in its oxy state - offers unique opportunities to probe oxygen metabolism in blood and tissues. The magnetic susceptibility χ of blood scales linearly with blood oxygen saturation, which can be obtained by measuring the magnetic field ΔB of the intravascular MR signal relative to tissue. In contrast to χ, the induced field ΔB is non-local. Therefore, to obtain the intravascular susceptibility Δχ relative to adjoining tissue from the measured ΔB demands solution of an inverse problem. Fortunately, for ellipsoidal structures, to which a straight, cylindrically shaped blood vessel segment conforms, the solution is trivial. The article reviews the principle of MR susceptometry-based blood oximetry. It then discusses applications for quantification of whole-brain oxygen extraction - typically on the basis of a measurement in the superior sagittal sinus - and, in conjunction with total cerebral blood flow, the cerebral metabolic rate of oxygen (CMRO₂ ). By simultaneously measuring flow and venous oxygen saturation (SvO₂ ) a temporal resolution of a few seconds can be achieved, allowing the study of the response to non-steady-state challenges such as volitional apnea. Extensions to regional measurements in smaller cerebral veins are also possible, as well as voxelwise quantification of venous blood saturation in cerebral veins accomplished by quantitative susceptibility mapping (QSM) techniques. Applications of susceptometry-based oximetry to studies of metabolic and degenerative disorders of the brain are reviewed. Lastly, the technique is shown to be applicable to other organ systems such as the extremities using SvO₂ as a dynamic tracer to monitor the kinetics of the microvascular response to induced ischemia. Copyright © 2016 John Wiley & Sons, Ltd.

Acute improvement of endothelial functions after oral ingestion of isohumulones, bitter components of beer

Isohumulones, principal components of the bitter taste of beers, have antioxidant capacity. We studied i) the effects of oral ingestion of isomerized hop extract (IHE) on the endothelial functions in smokers as well as non-smokers and ii) the effects of IHE on cultured endothelial cells in high oxidative stress state. Twelve cigarette smokers and eleven non-smokers ingested IHE and placebo in a randomized crossover design. Flow-mediated vasodilatation (FMD) was measured using ultrasonography. We also studied the effects of isohumulones on i) the cell viability under hypoxia and ii) the levels of angiotensin II (AT-II)-induced reactive oxygen species (ROS) in the cultured human aortic endothelial cells (HAECs). At baseline, the FMDs of the smokers were significantly lower than those of the non-smokers. The FMDs increased significantly after 30 min and 120 min of IHE ingestion in both the smokers and the non-smokers. IHE protected the HAECs from hypoxia-induced cell death as assessed by cell viability. IHE also reduced the AT-II-induced intracellular ROS level. Oral ingestion of IHE appears to exert acute beneficial effects on the endothelial functions in both the smokers and non-smokers, and the in vitro experiments using HAECs suggested that the effect be through reducing intracellular oxidative stress.

Review of Journal of Cardiovascular Magnetic Resonance 2015

There were 116 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2015, which is a 14 % increase on the 102 articles published in 2014. The quality of the submissions continues to increase. The 2015 JCMR Impact Factor (which is published in June 2016) rose to 5.75 from 4.72 for 2014 (as published in June 2015), which is the highest impact factor ever recorded for JCMR. The 2015 impact factor means that the JCMR papers that were published in 2013 and 2014 were cited on average 5.75 times in 2015. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is <25 % and has been falling because the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality papers to JCMR for publication.

Endovascular Therapy Research in Lower Limb Peripheral Arterial Disease Published Over a 5-Year Period: Who is Publishing and Where?

INTRODUCTION

Peripheral arterial disease (PAD) is being increasingly managed by endovascular therapies. In this study, we identified the clinical services publishing research as well as the journals of publication over a 5-year period.

METHODS

Twenty keywords and phrases related to endovascular intervention were identified, and a literature search was performed through the PubMed database from January 2009 to January 2014. Inclusion criteria were English language, study population more than five patients, and matching the keyword search. Eligible studies were collated into a database and classified by journal of publication, PubMed number, article title, publishing clinical service, type of publication, country of origin, and authors.

RESULTS

825 studies from 114 different journals were identified. 297 papers were excluded. Of the 528 included papers, 204 (39%) were published by Vascular Surgery (VS), 157 (30%) by Interventional Radiology (IR), 101 (19%) by Cardiology, 43 (8%) by Angiology, 6 (1%) by Vascular Medicine, and 17 (3%) from miscellaneous services. 283 (54%) studies originated from Europe, 157 (30%) from North America, 76 (14%) from Asia, 6 from Australia, 3 each from South America and Africa. IR published the most papers on PAD endovascular intervention in Europe with VS second while this trend was reversed in the USA. The 528 papers were published in 98 different journals with retrospective case series (72%), the majority.

CONCLUSION

IR continues to play a significant research role in endovascular intervention in PAD, particularly in Europe, and specifically in below the knee intervention, pedal intervention, and drug-eluting technologies.

Required temporal resolution for accurate thoracic aortic pulse wave velocity measurements by phase-contrast magnetic resonance imaging and comparison with clinical standard applanation tonometry

Background

Pulse wave velocity (PWV) is a biomarker for arterial stiffness, clinically assessed by applanation tonometry (AT). Increased use of phase-contrast cardiac magnetic resonance (CMR) imaging allows for PWV assessment with minor routine protocol additions. The aims were to investigate the acquired temporal resolution needed for accurate and precise measurements of CMR-PWV, and develop a tool for CMR-PWV measurements.

Methods

Computer phantoms were generated for PWV = 2–20 m/s based on human CMR-PWV data. The PWV measurements were performed in 13 healthy young subjects and 13 patients at risk for cardiovascular disease. The CMR-PWV was measured by through-plane phase-contrast CMR in the ascending aorta and at the diaphragm level. Centre-line aortic distance was determined between flow planes. The AT-PWV was assessed within 2 h after CMR. Three observers (CMR experience: 15, 4, and <1 year) determined CMR-PWV. The developed tool was based on the flow-curve foot transit time for PWV quantification.

Results

Computer phantoms showed bias 0.27 ± 0.32 m/s for a temporal resolution of at least 30 ms. Intraobserver variability for CMR-PWV were: 0 ± 0.03 m/s (15 years), -0.04 ± 0.33 m/s (4 years), and -0.02 ± 0.30 m/s (<1 year). Interobserver variability for CMR-PWV was below 0.02 ± 0.38 m/s. The AT-PWV overestimated CMR-PWV by 1.1 ± 0.7 m/s in healthy young subjects and 1.6 ± 2.7 m/s in patients.

Conclusions

An acquired temporal resolution of at least 30 ms should be used to obtain accurate and precise thoracic aortic phase-contrast CMR-PWV. A new freely available research tool was used to measure PWV in healthy young subjects and in patients, showing low intra- and interobserver variability also for less experienced CMR observers.

Mitochondrial Regulation of the Muscle Microenvironment in Critical Limb Ischemia

Critical limb ischemia (CLI) is the most severe clinical presentation of peripheral arterial disease and manifests as chronic limb pain at rest and/or tissue necrosis. Current clinical interventions are largely ineffective and therapeutic angiogenesis based trials have shown little efficacy, highlighting the dire need for new ideas and novel therapeutic approaches. Despite a decade of research related to skeletal muscle as a determinant of morbidity and mortality outcomes in CLI, very little progress has been made toward an effective therapy aimed directly at the muscle myopathies of this disease. Within the muscle cell, mitochondria are well positioned to modulate the ischemic cellular response, as they are the principal sites of cellular energy production and the major regulators of cellular redox charge and cell death. In this mini review, we update the crucial importance of skeletal muscle to CLI pathology and examine the evolving influence of muscle and endothelial cell mitochondria in the complex ischemic microenvironment. Finally, we discuss the novelty of muscle mitochondria as a therapeutic target for ischemic pathology in the context of the complex co-morbidities often associated with CLI.