Vascular Responses to Acute Induced Inflammation With Aging: Does Fitness Matter?

Acute inflammation impairs vascular function in an age-dependent manner and affects cardiovascular event risk. Regular aerobic exercise preserves vascular function with aging and potentially modifies how acute inflammation affects the vasculature. We hypothesize high cardiorespiratory fitness may accompany greater arterial responsiveness post-acute inflammation in older adults.

Acute inflammation elicits decreased blood pressure but similar arterial stiffness in young African American adults

African Americans (AA) have a higher risk for cardiovascular disease (CVD) as compared to their White (W) counterparts. CVD is characterized by increased blood pressure (BP), arterial stiffness and systemic inflammation. An acute inflammatory stimulus may explain physiological manifestations responsible for amplified CVD in AA that are not apparent at rest. The purpose of this study was to evaluate central and peripheral BP, central and local arterial stiffness, and indices of pulse wave morphology in young healthy AA and W participants in response to acute inflammation. Concentrations of the inflammatory cytokine interleukin-6 (IL-6) and measures of central and peripheral BP, central arterial stiffness (carotid-femoral pulse wave velocity (cfPWV)), local carotid arterial stiffness (β-stiffness, elastic modulus (Ep)), and indices of pulse wave morphology were assessed in 28 participants (21 ± 2 years, AA: n = 11) at baseline (BL), 24 h and 48 h post-inflammation. Changes in IL-6 concentrations (ΔIL-6) were significantly greater at 24 h as compared to 48 h post-inflammation (0.652 ± 0.644 vs. -0.146 ± 0.532 pg/μl, P ≤ 0.0001). Among AA participants, central and peripheral diastolic BP were significantly decreased at 24 h post-inflammation as compared to BL (aortic diastolic BP: -4 ± 4 mmHg, P = 0.016; brachial diastolic BP: -4 ± 4 mmHg, P = 0.014). AA participants also experienced a significant decrease in central and peripheral mean arterial BP at 48 h post-inflammation as compared to BL (aortic mean arterial pressure: -4 ± 4 mmHg, P = 0.009; brachial mean arterial pressure: -4 ± 4 mmHg, P = 0.012). Despite haemodynamic changes, there were no differences in central or local carotid arterial stiffness or indices of pulse wave morphology.

Arterial Stiffness following Endurance and Resistance Exercise Sessions in Older Patients with Coronary Artery Disease

Arterial stiffness (AS) is associated with coronary artery disease (CAD). Acute endurance training decreases AS, whereas acute resistance training increases it. However, these results are from studies in apparently healthy adults, and there is no information on the effects of such afterload AS in elderly patients with CAD. We aimed to investigate the effect of acute endurance or resistance training on the time course of changes in the indices of AS in elderly patients with CAD in order to understand how stiffness responds after training. We tested 18 trained men with CAD. AS was measured using central and peripheral pulse wave velocity (PWV) after 15 min of rest and after 5, 15, and 30 min of endurance and resistance training sessions. The endurance session consisted of high-intensity interval walking at 85-90% of maximum heart rate, and the resistance session consisted of 70% of the maximum of one repetition. An interaction effect was found for central and peripheral PWV (p ≤ 0.001; carotid, η² = 0.72; aortic, η² = 0.90; femoral, η² = 0.74), which was due to an increase in PWV after resistance and a decrease in central and peripheral PWV after endurance. This study demonstrates that training mode influences the time course of AS responses to acute exercise in these patients. Acute endurance training decreased AS, whereas resistance training significantly increased it.

Similar inflammatory response and conduit artery vascular function between sexes following induced inflammation

NEW FINDINGS

What is the central question of this study? Are there sex differences in vascular function following induced inflammation when oestrogen is typically similar between sexes? What is the main finding and its importance? The present study suggests no sex differences in conduit artery vascular responses to acutely induced inflammation during the low-oestrogen phase of the menstrual cycle in premenopausal women. However, women exhibit lower microvascular function than men. Overall, the results underpin the role of oestrogen in previously observed sex differences and the importance of reporting the phase in the hormonal cycle when women are studied.

ABSTRACT

Sex differences in cardiovascular disease incidence in premenopausal women and age-matched men have been attributed to the cardioprotective influence of oestrogen. However, limited knowledge exists regarding sex differences following acute inflammation when oestrogen concentrations are lower in women. We evaluated sex differences in vascular responses to induced inflammation when oestrogen concentrations are typically lower in women (early follicular phase or placebo phase of hormonal contraception). In 15 women and 14 men, interleukin-6 (IL-6) concentrations and vascular function [via brachial artery flow-mediated dilatation (FMD)] were assessed at baseline (BL) and 24 (24H) and 48 hours (48H) after administration of influenza vaccine. After induction of inflammation, both sexes exhibited an increase in IL-6 concentrations at 24H [mean (SD) BL vs. 24H: women, 0.563 (0.50) vs. 1.141 (0.65) pg/ml; men, 0.385 (0.17) vs. 1.113 (0.69) pg/ml; P < 0.05] that returned to near-baseline concentrations by 48H (BL vs. 48H, P > 0.05). There were no sex differences in FMD, allometrically scaled FMD or IL-6 concentrations at any time point (P > 0.05). Notably, women exhibited significantly lower microvascular function than men at every time point [P < 0.05; reactive hyperaemic area under the curve (in arbitrary units): women, BL 35,512 (14,916), 24H 34,428 (14,292) and 48H 39,467 (13,936); men, BL 61,748 (27,324), 24H 75,028 (29,051) and 48H 59,532 (13,960)]. When oestrogen concentrations are typically lower in women, women exhibit a similar inflammatory response and conduit artery function, but lower microvascular response to reactive hyperaemia, in comparison to age-matched men.

Vascular consequences of inflammation: a position statement from the ESH Working Group on Vascular Structure and Function and the ARTERY Society

: Inflammation is a physiological response to aggression of pathogenic agents aimed at eliminating the aggressor agent and promoting healing. Excessive inflammation, however, may contribute to tissue damage and an alteration of arterial structure and function. Increased arterial stiffness is a well recognized cardiovascular risk factor independent of blood pressure levels and an intermediate endpoint for cardiovascular events. In the present review, we discuss immune-mediated mechanisms by which inflammation can influence arterial physiology and lead to vascular dysfunction such as atherosclerosis and arterial stiffening. We also show that acute inflammation predisposes the vasculature to arterial dysfunction and stiffening, and alteration of endothelial function and that chronic inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease and psoriasis are accompanied by profound arterial dysfunction which is proportional to the severity of inflammation. Current findings suggest that treatment of inflammation by targeted drugs leads to regression of arterial dysfunction. There is hope that these treatments will improve outcomes for patients.

Race-specific changes in endothelial inflammation and microRNA in response to an acute inflammatory stimulus

Both aberrant vascular reactivity to acute cardiovascular stress and epigenetic mechanisms such as microRNA (miR) may underlie the increased propensity for African Americans (AA) to develop cardiovascular disease. This study assessed racial differences in acute induced endothelial inflammation and related miRs. Cultured human umbilical vein endothelial cells (HUVECs) derived from AA and Caucasian Americans (CA) were exposed to influenza vaccine to determine changes in inflammatory markers, endothelial nitric oxide synthase (eNOS), and miR expression/release. Endothelial function [flow-mediated dilation (FMD)], circulating IL-6, and circulating miR were also measured in young, healthy AA and CA individuals before and after receiving the influenza vaccine. There were no significant racial differences in any parameters at baseline. The vaccine induced increases in IL-6 release (24%, P = 0.02) and ICAM-1 mRNA (40%, P = 0.03), as well as reduced eNOS mRNA (24%, P = 0.04) in AA HUVECs, but not in CA HUVECs (all P > 0.05). Intracellular levels of anti-inflammatory miR-221-3p and miR-222-3p increased specifically in CA HUVECs (72% and 53%, P = 0.04 and P = 0.06), whereas others did not change in either race. HUVEC secretion of several miRs decreased in both races, whereas the release of anti-inflammatory miR-150-5p was decreased only by AA cells (-30%, P = 0.03). In individuals of both races, circulating IL-6 increased approximately twofold 24 h after vaccination (both P < 0.01) and returned to baseline levels by 48 h, whereas FMD remained unchanged. Although macrovascular function was unaffected by acute inflammation in AA and CA individuals, AA endothelial cells exhibited increased susceptibility to acute inflammation and unique changes in related miR.NEW & NOTEWORTHY Used as an acute inflammatory stimulus, the influenza vaccine induced an inflammatory response and decreased eNOS gene expression in endothelial cells derived from African Americans, but not Caucasian Americans. Race-specific changes in intracellular expression and release of specific microRNAs also occurred and may contribute to an exaggerated inflammatory response in African Americans. In vivo, the vaccine caused similar systemic inflammation but had no effect on endothelial function or circulating microRNAs in individuals of either race.

Initiating guideline-concordant gout treatment improves arterial endothelial function and reduces intercritical inflammation: a prospective observational study

Background

Patients with gout have arterial dysfunction and systemic inflammation, even during intercritical episodes, which may be markers of future adverse cardiovascular outcomes. We conducted a prospective observational study to assess whether initiating guideline-concordant gout therapy with colchicine and a urate-lowering xanthine oxidase inhibitor (XOI) improves arterial function and reduces inflammation.

Methods

Thirty-eight untreated gout patients meeting American College of Rheumatology (ACR)/European League Against Rheumatism classification criteria for gout and ACR guidelines for initiating urate-lowering therapy (ULT) received colchicine (0.6 mg twice daily, or once daily for tolerance) and an XOI (allopurinol or febuxostat) titrated to ACR guideline-defined serum urate (sU) target. Treatment was begun during intercritical periods. The initiation of colchicine and XOI was staggered to permit assessment of a potential independent effect of colchicine. Brachial artery flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) assessed endothelium-dependent and endothelium-independent (smooth muscle) arterial responsiveness, respectively. High-sensitivity C-reactive protein (hsCRP), IL-1β, IL-6, myeloperoxidase (MPO) concentrations, and erythrocyte sedimentation rate (ESR) assessed systemic inflammation.

Results

Four weeks after achieving target sU concentration on colchicine plus an XOI, FMD was significantly improved (58% increase, p = 0.03). hsCRP, ESR, IL-1β, and IL-6 also all significantly improved (30%, 27%, 19.5%, and 18.8% decrease respectively; all p ≤ 0.03). Prior to addition of XOI, treatment with colchicine alone resulted in smaller numerical improvements in FMD, hsCRP, and ESR (20.7%, 8.9%, 13% reductions, respectively; all non-significant), but not IL-1β or IL-6. MPO and NMD did not change with therapy. We observed a moderate inverse correlation between hsCRP concentration and FMD responsiveness (R = − 0.41, p = 0.01). Subgroup analyses demonstrated improvement in FMD after achieving target sU concentration in patients without but not with established cardiovascular risk factors and comorbidities, particularly hypertension and hyperlipidemia.

Conclusions

Initiating guideline-concordant gout treatment reduces intercritical systemic inflammation and improves endothelial-dependent arterial function, particularly in patients without established cardiovascular comorbidities.

No effect of fitness on brachial or forearm vascular function during acute inflammation in young adults

Acute inflammation is associated with increased risk of cardiovascular events and impaired vasodilatory capacity. Vasodilatory capacity can be measured in different segments of the arterial tree; however, it is unknown if the effects of acute inflammation are vascular segment-specific or if inflammation-induced dysfunction can be attenuated by factors that modulate cardiovascular risk, such as high cardiorespiratory fitness. The purpose of this study was to determine the effect of acute inflammation and fitness on conduit artery, resistance artery, and microvascular function in healthy, young adults. Vascular function was assessed at baseline and 24 h after a typhoid vaccination in 11 low-fit (5 male, 24 yr of age, 34.5 ± 2.9 ml·kg^-1·min^-1 peak O₂ uptake (V̇o_2peak)] and 12 high-fit (7 male, 27 yr of age, 56.4 ± 9.7 ml·kg^-1·min^-1 V̇o_2peak) young adults. Vascular assessments included flow-mediated dilation (FMD) of the brachial artery, forearm reactive hyperemia (RH) via venous occlusion plethysmography, and near-infrared spectroscopy (NIRS) during a 5-min arterial occlusion. Acute inflammation was evident with increases in IL-6 and C-reactive protein (P < 0.01), and mean arterial pressure did not change (P = 0.33). FMD was lower in the high-fit group, yet it was reduced in both groups at 24 h, even after controlling for shear (P < 0.05). No effect of acute inflammation was observed for RH or NIRS (P > 0.05). Acute inflammation had nonuniform effects on vascular function throughout the arterial tree in young adults, and fitness did not alter the vascular response. This suggests that cardiorespiratory fitness may not protect the vasculature during acute inflammation in young adults in the absence of age- or disease-related decline in vascular function.

Acute systemic inflammation reduces both carotid and aortic wave reflection in healthy adults

Acute inflammation increases the risk of cardiac and cerebrovascular events, possibly related to alterations in the hemodynamic load. Wave reflection at the aorta and carotid provides insight into downstream vascular changes and hemodynamic load at the heart and brain. Acute inflammation has been suggested to reduce wave reflection via downstream vasodilation; however, this is not firmly established and has only been investigated at the aorta. We sought to explore the effect of acute inflammation on aortic and carotid hemodynamics in healthy, young adults. Pressure waveforms were collected via radial and carotid applanation tonometry in 23 adults (26 ± 4 years) before and 24 h after a typhoid vaccination. Waveforms were calibrated to brachial mean and diastolic pressure, and waveform separation analyses (WSA) were performed, yielding augmentation index, reflection index, time to reflection (Tr), forward (Pf) and reflected (Pb) wave magnitude, and pulse wave velocity. Arterial diameters and carotid stiffness were measured via ultrasonography. Acute inflammation reduced wave reflection at 24 h in both the aorta and carotid (P < 0.05) without changes in mean pressure. WSA did not reveal independent changes in Pf, Pb, or Tr (P > 0.05). Arterial stiffness did not change; however, brachial and carotid artery diameters increased. Acute inflammation reduces wave reflection in the aorta and carotid artery in young adults, potentially due to downstream/peripheral vasodilation. Reduced aortic wave reflection did not disturb the cardiac workload; however, reductions in carotid wave reflection may render the brain vulnerable to pulsatile hemodynamics. These findings may have implications for cardiac and cerebrovascular risk during acute inflammation.