Joyner, Michael J.

Patients with HFrEF exhibit severe exercise intolerance. One of the primary peripheral mechanisms contributing to exercise intolerance in patients with HFrEF is locomotor muscle group III/IV afferent feedback. However, it is unknown whether these afferents impact the central and peripheral responses during submaximal cycling exercise. Herein, we demonstrate that inhibition of locomotor muscle group III/IV afferent feedback elicited increases in stroke volume during submaximal exercise in HFrEF, but not in healthy controls.

AbstractCOVID‐19 convalescent plasma (CCP) was among the few frontline therapies used to treat COVID‐19. After large randomized controlled trials (RCTs) relying on late use in hospitalized patients and/or low antibody titres failed to meet their predefined primary endpoint, the infectious disease community reduced usage of CCP in favour of monoclonal antibodies. Consequently, there are CCP stocks at most transfusion centres worldwide, although scattered usage continues. Further, better designed RCTs are also being launched. The urgent question here is: should we use CCP units collected months before given the largely changed viral variant landscape? We review here in vitro evidence that discourages usage of such CCP units against Delta and other variants of concern. CCP collections should be continued in order to update the armamentarium of therapeutics against vaccine breakthrough infections or in unvaccinated patients and is especially relevant in next‐generation RCTs.

Longitudinal studies assessing durability of the anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) humoral immune response have generated conflicting results. This has been proposed to be due to differences in patient populations, the lack of standardized methodologies, and the use of assays that measure distinct aspects of the humoral response.

COVID-19 convalescent plasma (CCP) is currently under investigation for both treatment and post-exposure prophylaxis. The active component of CCP mediating improved outcome is commonly reported as specific antibodies, particularly neutralizing antibodies, with clinical efficacy characterized according to the level or antibody affinity. In this review, we highlight the potential role of additional factors in CCP that can be either beneficial (e.g., AT-III, alpha-1 AT, ACE2+ extracellular vesicles) or detrimental (e.g., anti-ADAMTS13, anti-MDA5 or anti-interferon autoantibodies, pro-coagulant extracellular vesicles). Variations in these factors in CCP may contribute to varied outcomes in patients with COVID-19 and undergoing CCP therapy. We advise careful, retrospective investigation of such co-factors in randomized clinical trials that use fresh frozen plasma in control arms. Nevertheless, it might be difficult to establish a causal link between these components and outcome, given that CCP is generally safe and neutralizing antibody effects may predominate.

Background Prostaglandins, such as cyclooxygenase (COX), may play an important role in regulating the cerebral blood flow response to a stimulus. We have previously shown that the vasodilatory response to a chemical stimulus decreases with age, and this difference is abolished by COX inhibition. However, the effects of COX inhibition on the cerebrovascular response to an increase in metabolic demand during a cognitive challenge is unknown. This information is important due to the frequent use of COX inhibitors for pain management. Thus, the purpose of this study was to determine the effect of COX inhibition on the cerebrovascular response to a metabolic stimulus in young and older adults. Methods Seventy‐six participants, including 42 young adults (YA; 26 ± 5 y) and 34 older adults (OA; 64 ± 6 y) completed the Stroop Color Word Test, which is a test of executive function. A subset of 42 participants (n = 22 YA, n = 20 OA) also completed the N‐back Test, which is a test of working memory. Beat‐to‐beat middle cerebral artery velocity (MCAv) and mean arterial pressure (MAP) were measured at baseline and in response to each cognitive test. Cerebrovascular conductance index (CVCi) was calculated as MCAv/MAP. The response to each cognitive test was calculated as the peak percent change (%Δ) from baseline. Oral administration of the COX inhibitor Indomethacin (Indo) was given at 1.2mg/kg. Cognitive tests were then repeated after a 120‐minute wash‐in period. Results At baseline, YA had higher MCAv, CVCi, and lower MAP (p<0.01 for all) compared to OA. There were no significant differences between groups in the %Δ from baseline during the Stroop or N‐back test (p>0.05). During Indo, YA had higher MCAv (p<0.01), CVCi (p<0.01), and lower MAP (p<0.05) compared to OA. Indo decreased baseline MCAv and CVCi in both groups (p<0.01 for all) but had no effect on MAP (p>0.05). During Indo, the %Δ in MCAv during Stroop and N‐back was lower in YA (p<0.01) compared to baseline in YA. During Indo, the %Δ in MCAv was lower during Stroop in OA (p<0.01), with a trend for significance in OA during N‐back (p=0.06) compared to baseline. In YA during Indo, the %Δ in MAP was lower during Stroop (p<0.01) with a trend for significance during Nback (p=0.08) compared to baseline. In OA, the %Δ in MAP during N‐back was lower during Indo compared to baseline (p<0.05). Indo had no effect on the %Δ in CVCi (p>0.05). Importantly, there were group differences in the %Δ in MAP during Indo, such that the change was greater in OA compared with YA during Stroop (14.1 ± 1.3% vs. 10.6 ± 1.0%; p<0.05). Conclusion After administration of Indo, OA increased MAP to a greater extent during the Stroop test when compared to YA. These results suggest that OA required a larger increase in blood pressure to complete a test of executive function during COX inhibition. Because some COX inhibitors attenuate cerebral blood flow, OA may need to augment blood pressure to complete this metabolically‐challenging task. Support or Funding Information This research was funded by NIH grant HL118154. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

A history of preeclampsia (PE) places women at higher risk for future cardiovascular disease and cognitive decline. We have previously shown that postmenopausal women with a history of PE demonstrated a reduced cerebral blood flow response to hypercapnia compared with postmenopausal women with a history of a normotensive pregnancy (NP). These findings suggest cerebrovascular effects of PE 30+ years postpartum. In addition, we have reported that women with a history of PE did not have an exaggerated pressor response to a sympathoexcitatory stimulus. However, it is possible that women with a history of PE may have an altered cerebral blood flow response to a sympathoexcitatory stimulus. In this study, middle cerebral artery blood velocity (MCAv) and beat‐to‐beat mean arterial blood pressure (MAP) were measured during isometric handgrip to fatigue (IHG) at 30% of maximal voluntary contraction followed by post‐exercise ischemia (PEI) for 90 seconds and a two minute recovery period (REC). Participants were postmenopausal women with a history of PE (n = 21; age at study = 58±5 y; years since last pregnancy = 35±3 y) and NP (n = 27; age at study = 58±5 y; years since last pregnancy = 35±3 y). Baseline MAP and MAP responses to IHG and PEI were similar between groups (p>0.05). PE women demonstrated lower MCAv at baseline (NP: 72±3 cm/s vs. PE: 57±4 cm/s), IHG (NP: 78±4 cm/s vs. PE: 63±4 cm/s), PEI (NP: 74±4 cm/s vs. PE: 60±4 cm/s), and REC (NP: 70±3 cm/s vs. PE: 58±4 cm/s) compared with NP women (p<0.05 for all). MCAv, when calculated as a percent change from baseline, was elevated during IHG in both PE and NP women as expected (p<0.05); however, PE women had an augmented MCAv response during the last third of IHG compared with NP women (NP: 9±2 % vs. PE: 13±2 %; p<0.05). PE women also had a higher MCAv response during REC compared with NP women (NP:−2±2% vs. PE: 3±2%; p<0.05). Importantly, these elevated MCAv responses occurred despite the fact that MAP was not different between groups. In summary, PE women demonstrated a lower basal cerebral blood velocity but an elevated cerebrovascular response to a sympathoexcitatory stimulus compared with NP women. This suggests that in postmenopausal women, there is an effect of pregnancy history on the sensitivity of the cerebral blood flow response to a sympathoexcitatory stimulus. Support or Funding Information NIH: AG 044170. This investigation was supported by the National Institutes of Health, under Ruth L. Kirschstein National Research Service Award T32 HL 007936 from the National Heart Lung and Blood Institute to the University of Wisconsin‐Madison Cardiovascular Research Center. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Objective The slope ratio (SR) is a metric that uses maximal expiratory flow‐volume (MEFV) curves to quantify lung‐emptying dynamics. SR values between 0.5–2.5 indicate homogeneous lung‐emptying, while values >2.5 are suggestive of heterogeneous lung‐emptying. Albuterol and exercise are commonly used to improve airflow in patients with cystic fibrosis (CF); however, the effects of these treatments on lung‐emptying dynamics are unknown. We hypothesized that SR values would decrease following albuterol and/or exercise, and that these decreases would be more pronounced following albuterol‐with‐exercise. Methods Nine patients (25±2 yrs, n=4 male, 5 female) diagnosed (genotype or sweat chloride) with CF underwent three interventions: i) albuterol (2.5 mg in 3 mL saline), ii) 30 mins of exercise (50% peak wattage), and iii) albuterol and exercise together. MEFV curves (spirometry) were obtained at 10 time points: immediately before (Pre) and 15 minutes after (T15) interventions. Forced expiratory volume in 1 second (FEV 1 ) and forced expiratory flow for 25–75% (FEF 25–75 ) of the forced vital capacity (FVC) were calculated for each curve. SR was calculated along the MEFV curve as the ratio between the tangent and chord slopes at serial volumes (200 mL increments), and SR values from 80%‐20% FVC were averaged to produce a single SR for each MEFV curve. Results Compared to exercise, albuterol and albuterol‐with‐exercise elicited greater increases in FEV 1 (Pre: 3.00±0.26 vs 2.99±0.25 vs 3.06±0.23 L, p>0.05; T15: 3.00±0.27 vs 3.27±0.30 vs 3.34±0.28 L, p=0.03; exercise vs albuterol vs exercise‐with‐albuterol, for each comparison respectively), FEF 25–75 (Pre: 2.52±0.40 vs 2.53±0.40 vs 2.57±0.36 L/s, p>0.05; T15: 2.48±0.39 vs 3.04±0.54 vs 3.10±0.43 L/s, p=0.04), and FVC (Pre: 4.19±0.38 vs 4.17±0.38 vs 4.22±0.37 L, p>0.05; T15: 4.16±0.39 vs 4.35±0.38 vs 4.40±0.41 L, p=0.02), as well as greater decreases in SR (Pre: 1.51±0.15 vs 1.56±0.12 vs 1.58±0.12, p>0.05; T15: 1.54±0.15 vs 1.46±0.17 vs 1.43±0.17, p=0.02). Changes in FEV 1 , FEF 25–75 , FVC, and SR were not different between albuterol and albuterol‐with‐exercise conditions (p>0.05). Reductions in SR were related to increases in FEV 1 following interventions (r=−0.55, p<0.01). Conclusions In contrast to exercise, albuterol caused CF patients to exhibit greater increases in FEV 1 , FEF 25–75 , and FVC, along with greater decreases in SR. There was no additive effect of exercise on albuterol. Changes in FEV 1 and SR were inversely correlated. These data suggest that albuterol promotes bronchodilation and homogeneous lung‐emptying in CF patients, and that the SR metric is effective for assessing patterns of bronchodilation following administration of different bronchodilators. Support or Funding Information Supported by HL131151 (SEB) and Mayo Clinic Internal Funding This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .