bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acetycholine activates WNK kinase signaling in endothelial cells to stimulate vasodilation
Authors: Garrud Tessa , Mata-Daboin Alejandro , Collier Daniel , Jaggar Jonathan 
Published: May 2023

The endothelium integrates numerous external signals to regulate vascular contractility. Vasodilators such as acetylcholine (ACh) bind to endothelial cell receptors and activate downstream signaling pathways which act on arterial smooth muscle cells to induce vasorelaxation. The physiological functions of anion channels, such as chloride Cl-channels, in endothelial cells is poorly understood. TMEM16A is a calcium (Ca2+)-activated Cl- channel expressed by endothelial cells. WNK kinase is a Cl--sensitive kinase present in endothelial cells that activates the downstream substrate kinases SPS-1 related proline/alanine rich kinase (SPAK) and oxidative-stress responsive kinase-1 (OSR1). The goal of this study was to examine the functional significance of TMEM16A channels and the WNK kinase pathway in endothelial cell-mediated vasodilation in resistance-size mesenteric arteries. Tamoxifen-inducible, endothelial cell-specific TMEM16A knockout (TMEM16A ecKO) mice and their controls (TMEM16Afl/fl) were used for experiments. ACh rapidly increased SPAK and OSR1 phosphorylation in TMEM16Afl/fl arteries and this effect was blocked by WNK463, a specific WNK kinase inhibitor. ACh did not increase SPAK or OSR1 phosphorylation, nor was there any effect of WNK463, in TMEM16A ecKO arteries. ACh increased the frequency and spatial spread of intracellular Ca2+ signals in endothelial cells of en face TMEM16Afl/fl arteries. The ACh-induced increase in Ca2+ signal frequency and spread in endothelial cells was inhibited by WNK 463, HC067047, a TRPV4 channel inhibitor, or TMEM16A knockout. WNK463, HC067047 or TMEM16A knockout also attenuated ACh-induced vasodilation in pressurized arteries. In contrast, WNK463 did not alter ACh-induced vasodilation in TMEM16A ecKO arteries. Taken together, our data suggest that ACh stimulates Ca2+ signaling in endothelial cells and vasodilation via WNK kinase-, TRPV4- and TMEM16A-dependent mechanism. Funding from NIH R01HL155180, NIH R01HL158846 and AHA 830462. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Postural hyperventilation in POTS is not driven by exaggerated peripheral chemoreceptor activity
Authors: Baker Jacquie , Incognito Anthony , Ranada Shaun , Phillips Aaron , Sheldon Robert , Wilson Richard , Raj Satish 
Published: May 2023

BACKGROUND: Postural Orthostatic Tachycardia Syndrome (POTS) is a chronic form of autonomic nervous system dysfunction primarily affecting premenopausal females. POTS patients experience chronic orthostatic symptoms, and a heart rate (HR) increase of ≥30 bpm within 10 min of standing in the absence of orthostatic hypotension (>20/10 mmHg decrease in blood pressure [BP]). On standing, patients can exhibit increased ventilation (VE) with subsequent reductions in end-tidal CO2 (i.e., hypocapnia). Hypocapnia exacerbates tachycardia and symptoms. Previous research has suggested exaggerated peripheral chemoreceptor (pChR) activity drives postural hyperventilation in POTS. OBJECTIVE: We explored exaggerated pChR activity in the pathophysiology of postural hyperventilation in POTS. HYPOTHESIS: We hypothesized that POTS patients have a greater VE reduction during pChR inhibition compared to healthy controls. METHODS: We conducted a randomized crossover trial of hyperoxia vs. normoxia while supine and during head-up tilt (HUT) in 25 POTS patients (F=25; age: 31±8 years) and 12 healthy controls (HC) (F=12; age: 31±6 years; p=0.8). To inhibit pChR, participants breathed 5x30sec bouts of normocapnic hyperoxia (O2: ~400mmHg). Continuous respiratory (VE, ETO2, ETCO2) and hemodynamics (HR, BP, stroke volume, cardiac output, systemic vascular resistance) were measured. Data are reported as mean±SD. Continuous variables were compared using a 3-factor mixed-effects model: [Group: Control vs. Patient] x [Position (repeated measure): supine vs. HUT] x [Gas (repeated measure): ON vs. OFF). RESULTS During normoxic HUT, VE increased relative to supine baseline in both POTS (Supine: 10.3±2.3 L/min, HUT: 15.2±4.2; p<0.001) and HC (Supine: 11.1±2.1 L/min, HUT: 12.9±2.3 L/min; p=0.04). As predicted, the ΔVE in response to HUT was significantly greater in POTS (4.8±3.3 L/min) vs. HC (1.8±1.6 L/min; p=0.001). During HUT, hyperoxia reduced VE in both POTS (p<0.001) and HC (p<0.001). However, the magnitude of the ventilatory inhibition was not different between groups (POTS: -1.9±1.0 L/min; HC: -1.8±1.0 L/min; p=1.0). CONCLUSION: POTS patients have increased postural VE relative to HC. During pChR inhibition with hyperoxia, VE was reduced in both HC and POTS, and the magnitude of ventilatory inhibition in response to hyperoxia was the same in both groups. These findings suggest pChR activity is not exaggerated in POTS patients, and thus is not the primary driver of postural hyperventilation observed in POTS. This work was supported by Standing up to POTS. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Role of scleraxis in angiotensin II-induced cardiac fibrosis
Authors: Chattopadhyaya Sikta , Nagalingam Raghu Sundaresan , Ledingham D. Allison , Czubryt Michael P. 
Published: May 2023

Cardiac fibrosis involves the activation and conversion of fibroblasts to myofibroblasts in response to pathophysiological stresses, resulting in structural and functional remodeling of the heart leading to heart failure and death. Although it affects millions of people worldwide, currently no medications are available against cardiac fibrosis. Similar to the pro-fibrotic growth factor TGF-β, angiotensin II (AngII) contributes to cardiac fibrosis, however AngII inhibitors are not used against fibrosis despite growing evidence of efficacy. AngII induces the nuclear translocation of Myocardin Related Transcription Factor-A (MRTF-A) which acts with Serum Response Factor (SRF) to play a major role in the conversion of fibroblasts to myofibroblasts, similar to the transcription factor scleraxis. Scleraxis has been shown by our lab to induce fibrosis by transactivating various pro-fibrotic gene promoters. Here we investigated whether AngII works through an MRTF-A/SRF/scleraxis pathway to induce cardiac fibrosis. AngII delivery (1mg/kg/day for 28 days) through osmotic mini-pumps in C57Bl/6 mice significantly increased blood pressure (systolic, diastolic, and mean) and cardiac hypertrophy compared to saline control group. In the AngII group, cardiac fibrosis was observed with enhanced mRNA expression of pro-fibrotic genes, Col1a1, Col3a1, periostin, and EDA-fibronectin. Interestingly there was a significant increase in scleraxis as well, suggesting its involvement in AngII-mediated fibrosis. Our in vitro studies of rat cardiac fibroblasts treated with AngII showed a significant increase in scleraxis mRNA and protein expression, and scleraxis knockdown significantly attenuated AngII-induced collagen expression, confirming a requirement for scleraxis in the AngII-mediated fibrosis pathway. NIH3T3 cells transfected with MRTF-A and SRF together showed a high level of induction of scleraxis expression. Luciferase assays in both COS7 and NIH3T3 cells showed that MRTF-A and SRF act together to regulate scleraxis expression by binding to and transactivating the scleraxis promoter, indicating that AngII activates a MRTF-A/SRF/scleraxis pathway for inducing cardiac fibrosis, therefore targeting scleraxis may be an effective anti-fibrotic strategy. Canadian Institutes of Health Research Project Grant This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Brachial vascular function after acute aerobic exercise in older adults with and without type 2 Diabetes mellitus
Authors: Marôco João , Arrais Inês , Silvestre Tiago , Pinto Marco , Laranjo Sérgio , Magalhães João , Santa-Clara Helena , Fernhall Bo , Melo Xavier 
Published: May 2023

Brachial vascular function after acute aerobic exercise in older adults with and without type 2 diabetes Purpose: The acute exercise model provides clinical insights regarding vascular dysfunction in adults with type 2 Diabetes Mellitus (T2DM), as it uncovers abnormalities not normally present at rest. However, whether vascular responses to acute exercise in adults with T2DM are intensity-dependent, and whether response patterns differ with aging and disease, remains unknown. Thus, we examined brachial artery flow-mediated dilation (FMD) and flow-mediated slowing (FMS) of pulse wave velocity (PWV), 10 and 60-min after an acute bout of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) in middle-aged and older men with and without T2DM compared to young men without T2DM. Hypothesis: HIIE would induce a larger decrease in FMD immediately after exercise cessation compared to MICE in older men with and without T2DM. Methods: Twelve males with (57-84 yr) and without (57-76 yr) T2DM, and 12 healthy young adults (20-40 yr), completed an isocaloric acute exercise bout of HIIE, MICE, and a non-exercise condition in randomized order. FMD and FMS were evaluated and offline analyzed by the same researcher following standard guidelines. Central and peripheral arterial stiffness were measured via applanation tonometry estimates of carotid-femoral PWV (cfPWV) and carotid dorsalis pedis PWV (cdPWV), respectively. Statistical inferences were performed using linear mixed models. Results: %FMD was reduced (d= - 5.94, 95% CI: -10.50 to -1.38 %, p=0.002), whereas %FMS was increased (d= 4.55, 95% CI: 0.62 to 8.48%, p=0.01), 10-min after HIIE only in older adults with T2DM, returning to resting values 60-min into recovery. Conversely, %FMD was increased (d= 5.33, 95% CI: 0.76 to 9.89%, p=0.009) 10-min after MICE only in older adults with T2DM, while cfPWV and cdPWV remained unchanged following HIIE and MICE in all groups. There were no group differences at rest in brachial %FMD and %FMS, while cfPWV and cdPWV were higher in older adults with T2DM compared to age-matched controls (cfPWV: d= 1.94, 95% CI: 0.44 to 3.44 m. s-1, p=0.009). Conclusions: We found evidence of intensity- and disease-dependent vascular responses to acute aerobic exercise. These findings suggest that high-intensity acute exercise transiently impairs vascular function in older adults with T2DM, which may constitute an important trigger for exercise-based long-term improvements in vascular function. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Low Type 3 Deiodinase (DIO3) activity Post-Myocardial Infarction leads to a Greater Incidence of Heart Failure in Female Mice
Authors: Teixeira Silvania , Bethea Maigen , Cavasin Maria , Knaub Leslie , Hernandez Arturo , Scalzo Rebecca , Sandoval Darleen 
Published: May 2023

Objective: Studies in male mice show that myocardial infarction (MI) leads to the upregulation of type 3 deiodinase (DIO3), the enzyme that inactivates thyroid hormones, which has been regarded as a predictor of poor outcomes after MI. Interestingly, a recent human study has shown a sex-specific regulation of DIO3 after an ischemic event, with women presenting a significant downregulation of this gene. Therefore, this study aims to investigate the biological importance of DIO3 activity on MI recovery in female mice. Methods: Female mice expressing a tamoxifen-inducible Cre-recombinase under the control of the cardiomyocyte-specific Myh6 promoter and carrying a floxed selenocysteine insertion sequence in the DIO3 gene were used to reduce heart DIO3 activity. Animals were treated with tamoxifen (1.5 mg, once daily, for 3 days). MI was induced via ligation of the left anterior descending coronary artery 4 weeks after tamoxifen treatment. Ejection fraction (EF) was measured at baseline, 2 weeks, and 4 weeks after MI induction using echocardiography. Animals were sacrificed 4 weeks post-MI, and heart mitochondrial respiration was measured using Oxygraph-2K. Results: Our data demonstrated that 4 weeks post-MI, females with low DIO3 heart activity show low EF compared to wild-type control mice. We also observed that the cardiac mitochondria of females with low DIO3 activity after MI had lower lipid-linked respiration compared to wild-type control mice. Discussion/Significance of Impact: Impaired cardiomyocyte mitochondrial function has been linked to a reduced ability to recover from MI. We found that lowering cardiac DIO3 activity in female mice caused a reduction in heart function and in cardiomyocyte mitochondrial respiration, suggesting these animals have a reduced ability to recover from MI. The data have important translational implications and clinical significance given that it challenges the current knowledge about DIO3 function after MI and will contribute to explaining why women face a 20% greater risk than men of developing heart failure after MI. Furthermore, it highlights the importance of DIO3 on female heart function since the human DIO3 gene is transcriptionally responsive to estrogen, and MI numbers are relatively low in premenopausal women but significantly increase after menopause. CTSA Grant UL1 TR002535, KL2 TR002534, & TL1 TR002533 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
ROS scavenger TEMPOL mitigates TNF alpha induced ER stress in hASM cells
Authors: Perez-Franco Rosana , Yap Jane , Blandon-Delgado Leslly , Panigrahy Nisha , Dasgupta Debanjali , Delmotte Philippe , Sieck Gary 
Published: May 2023

The impact of airway inflammation is mediated by pro-inflammatory cytokines such as tumor necrosis factor alpha (TNFα), which underlies several respiratory diseases, including COVID-19, asthma, chronic bronchitis, and chronic obstructive pulmonary disease (COPD). In human airway smooth muscle (hASM) cells, exposure to TNFα leads to an accumulation of unfolded proteins in the ER, which triggers a homeostatic ER stress response activating a signaling cascade to restore normal function. Previously, we showed that TNFα selectively activates the inositol-requiring enzyme 1α (IRE1α)/X-box binding protein 1 (XBP1) ER stress pathway in hASM cells. Most likely, the protein unfolding in hASM cells caused by TNFα results from an increase in reactive oxygen species (ROS) formation. We hypothesize that ER stress induced by TNFα is mitigated by the ROS scavenger TEMPOL. Primary hASM cells were isolated from bronchiolar tissue samples obtained from 5 patients (both sexes included) who had no history of respiratory diseases. hASM cells were serum deprived for 48 h before treatment with 1) TNFα (20 ng/ml) for 12 h; 2) TEMPOL (500 μM) for 30 min followed by TNFα (20 ng/ml) for 12 h; and 3) untreated control for 12 h. At the end of the treatment period, hASM cells were processed for determination of protein expression through Western blotting. Activation of the ER stress response was assessed by phosphorylation of IRE1α and splicing of XBP1. Confirming our previous results, we found that 12 h TNFα exposure induced an ER stress response in hASM cells, evidence by phosphorylation of IRE1α and XBP1 splicing. Treating hASM cells with TEMPOL before exposure to TNFα mitigated the ER stress response. These results support our hypothesis and indicate that ROS scavenging prevents TNFα induced protein unfolding and triggering of the IRE1α/XBP1 ER stress pathway. R01HL 157984 (GCS) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Cyclooxygenase inhibition attenuates peripheral venous distension reflex in healthy humans
Authors: Hamaoka Takuto , Leuenberger Urs , Kronfli Anthony , Gao Zhaohui , Braha Cheryl , Luck Jonathan , Dalton Paul , Sinoway Lawrence , Cui Jian 
Published: May 2023

Background: Venous distension in limbs evokes a pressor reflex (venous distension reflex, VDR). Group III and IV nerves, innervating peripheral veins, are suggested as the afferent arm of the VDR. Prostaglandins stimulate/sensitize group III/IV nerves. The purpose of this study was to evaluate the effect of cyclooxygenase (COX) blockade on muscle sympathetic nerve activity (MSNA) and blood pressure (BP) responses to venous distension. Hypothesis: We hypothesized that inhibition of prostaglandin synthesis by local COX blockade would attenuate the MSNA and BP responses to peripheral venous distension. Methods: Nineteen healthy volunteers (age, 27 ± 5 years) participated in the study with a randomized, double-blind, placebo-controlled, and crossover study design with two separate visits. To induce venous distension, a volume of solution (saline alone or 9 mg ketorolac tromethamine in saline) was infused into the vein in the antecubital fossa of an arterially occluded forearm. During the procedure, beat-by-beat heart rate (HR), BP, and MSNA were recorded simultaneously. The vein size at the site with the catheter for the infusion was measured with ultrasound. This study is associated with a registered clinical trial (NCT03513770). Data and a summary of the results: In both visits, the venous distension procedure significantly increased the vein size, and the increase in vein size was not different between the visits (P > 0.05). A significant decrease (P < 0.001) in TXB2 level (an index for prostaglandin synthesis) by the procedure was observed only in the ketorolac visit. In both visits, the venous distension procedure significantly increased BP, HR, and MSNA (all, P < 0.05). The increase in mean arterial pressure (MAP) and MSNA in the ketorolac visit was significantly lower than in the control visit (ΔMAP, 7.0 ± 6.2 vs. 13.8 ± 7.7 mmHg; ΔMSNA, 6.0 ± 7.1 vs. 14.8 ± 7.7 bursts/minute; both, P < 0.05). Discussion and conclusion: The presented data show that COX blockade attenuates the responses in MSNA and BP to peripheral venous distension. The results suggest that COX products play a key role in evoking afferent activation responsible for the VDR. Vein size was measured with ultrasonography only at the catheter site. Some members of COX products have vasoactive effects. Future studies evaluating the effect of COX blockade on vein size in more detail using other approaches (e.g., magnetic resonance imaging) are warranted to verify the detailed mechanism of the attenuated VDR by the COX blockade. This study was supported by National Institutes of Health Grants R01 HL144781 (to J.C. and L.I.S). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effects of lower limb heating on the ankle-brachial index
Authors: Cui Jian , Aziz Faisal , Hamaoka Takuto , Blaha Cheryl , Luck Jonathan , Dalton Paul , Leuenberger Urs 
Published: May 2023

Background: Peripheral artery disease (PAD) is an atherosclerotic disease with luminal narrowing of blood vessels, leading to an obstruction of blood flow. It most commonly affects blood vessels of the lower extremities. The ankle-brachial index (ABI, the ratio of ankle pressure over brachial pressure) is a primary index in the diagnosis (ABI < 0.9) of PAD. However, resting ABI may not be sensitive enough to detect mild/moderate PAD in some patients. The ABI after a 5 -min exercise stress test is currently used to confirm a diagnosis of PAD in patients with classical symptoms of PAD, but with normal resting ABIs. However, not all of the patients can tolerate the treadmill test. The purpose of this study was to examine the effects of lower limb heating on the ABI measurement, since lower limb heating can also induce lower limb vasodilation as walking does. Hypothesis: We hypothesized that lower limb heating would specifically decrease ABI in PAD patients. Methods: In 10 PAD patients and 12 healthy control subjects, resting ABI was measured at first. Then, both feet and lower legs were immersed in warm water (~ 40 ºC) for 30 min. Thereafter, ABI was measured again. This study is associated with a registered clinical trial (NCT03900832). Data and a summary of the results: Lower limb heating did not significantly alter the hemodynamic variables in both groups. Lower limb heating significantly decreased the ABI of both legs in PAD patients (0.75 ± 0.03 to 0.67 ± 0.04, P = 0.003), and did not alter the ABI in healthy controls (1.01 ± 0.01 to 1.03 ± 0.01, P = 0.103). Discussion and Conclusion: The presented data show that lower limb heating decreases ABI in PAD patients, while it does not alter ABI in healthy individuals. The results suggest that lower limb heating can increase the sensitivity of the ABI measurement in PAD patients. Many patients with PAD can have comorbidities that are either absolute or relative contraindications to exercise treadmill testing. Moreover, many patients with intermittent claudication may not tolerate exercise treadmill testing. We speculate that the lower limb heating approach can be applied in these patients. Further studies on the mechanisms are warranted. This study was supported by National Institutes of Health Grants R01 HL141198 and R01 HL164571. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.