bluuebunny/crossref_metadata_2025 huggingface dataset:
Elevating CXCR7 improves angiogenic function of EPCs via Akt/GSK‐3β/Fyn‐mediated Nrf2 activation in diabetic limb ischemia
Authors: Dai Xiaozhen , Zeng Jun , Chen Jing , Cai Lu , Tan Yi
Published: November 2023

Rational

Endothelial progenitor cells (EPCs) respond to SDF‐1 through receptors CXCR7 and CXCR4. Whether SDF‐1 receptors involves in diabetes induced EPCs dysfunction remains unknown.

Objective

To determine the role of SDF‐1 receptors in diabetic EPCs dysfunction.

Methods and Results

CXCR7 expression, but not CXCR4 was reduced in EPCs from db/db mice, which coincided with impaired tube formation. Knockdown of CXCR7 impaired tube formation of EPCs from normal mice, while up‐regulation of CXCR7 rescued angiogenic function of EPCs from db/db mice. In normal EPCs treated with oxidized low‐density lipoprotein (ox‐LDL) and high glucose (HG) also reduced CXCR7 expression, impaired tube formation and increased oxidative stress and apoptosis. The damaging effects of ox‐LDL and HG were markedly reduced by SDF‐1 pretreatment in EPCs transduced with CXCR7 lentivirus (CXCR7‐EPCs) but not in EPCs transduced with control lentivirus (Null‐EPCs). Most importantly, CXCR7‐EPCs were superior to Null‐EPCs for therapy of ischemic limbs in db/db mice. Mechanistic studies demonstrated that ox‐LDL and HG inhibited Akt and GSK‐3β phosphorylation, nuclear export of Fyn and nuclear localization of Nrf2, resulting in inhibiting Nrf2 downstream target genes HO‐1, NQO‐1 and catalase, and a corresponding increase in EPC oxidative stress. This destructive cascade could be blocked by SDF‐1 treatment in CXCR7‐EPCs. Furthermore, inhibition of PI3K/Akt prevented SDF‐1/CXCR7‐mediated Nrf2 activation and blocked angiogenic repair. Moreover, Nrf2 knockdown almost completely abolished the protective effects of SDF‐1/CXCR7 on EPC function in vitro and in vivo.

Conclusions

Elevated expression of CXCR7 enhances EPC resistance to diabetes‐induced oxidative damage and improves therapeutic efficacy of EPCs for treating diabetic limb ischemia. The benefits of CXCR7 are mediated predominantly by the Akt/GSK‐3β/Fyn pathway producing increased activity of Nrf2.

Support or Funding Information

This study was supported in part by a Junior Faculty Award (1–13‐JF‐53) from American Diabetes Association, an Innovative Grant (1‐INO‐2014‐122‐A‐N) from Juvenile Diabetes Research Foundation, NSFC projects (81573435, 81200917, 81200239, 81370917).
Chloroquine Attenuates Endothelium‐dependent Relaxation in Mouse Coronary Artery
Authors: Zhang Qian , Wang Jian , Makino Ayako
Published: November 2023

Chloroquine (CQ) is widely used as an antimalarial drug and it is also effective in treating the symptoms of lupus. It has been reported that CQ exhibits cardiotoxicity and has an adverse effect on nerve system by overdose or prolonged treatment of CQ. However, little is known about the effect of CQ on cardiovascular system. This study was designed to examine the effect of CQ on vascular relaxation in coronary artery. Third‐ or fourth‐order small coronary arteries were dissected from mice and the rings were mounted in a wire myograph with 20μm wires. Endothelium‐dependent relaxation was conducted by ACh administration in a dose‐dependent manner. Endothelium‐derived hyperpolarization (EDH)‐dependent relaxation was observed by inhibition of NO (via L‐NAME, 100 μmol/L) and prostacyclin (via indomethacin, 10 μmol/L) during ACh‐induced relaxation. A cocktail of apamin (100 nmol/L) and TRAM34 (10 μmol/L) was used to inhibits EDH‐dependent relaxation. CQ (10 μmol/L) was treated for 30 min before vascular constriction by PGF2α. CQ significantly inhibited endothelium‐dependent relaxation compared to the control (vehicle treatment), whereas CQ had no effect on sodium nitroprusside‐induced relaxation (endothelium‐independent relaxation). Interestingly, EDH‐dependent relaxation was markedly enhanced by the pretreatment of CQ compared to the vehicle pretreatment. ACh‐induced relaxation was diminished in the presence of L‐NAME, indomethacin, apamin, and TRAM34. These data suggest that CQ might inhibit endothelium‐dependent relaxation via, at least in part, the decrease in NO production and/or NO bioavailability in endothelial cells, but not due to altering EDH‐dependent relaxation.

Support or Funding Information

NIH/HL115578
Endothelial Specific Molecule 1 (Esm‐1) Inhibits Macrophage Infiltration in a Mouse Model of Goodpasture's Syndrome
Authors: Zheng Xiaoyi , Higdon Lauren , Maltzman Jonathan , Bhalla Vivek
Published: November 2023

Goodpasture's syndrome is an autoimmune disorder caused by pathogenic antibodies to kidney and lung basement membranes causing acute kidney and lung injury, respectively. We modeled this syndrome by treatment with anti‐GBM (Glomerular Basement Membrane) antibodies leading to glomerular and tubulointerstitial inflammation in mice. Endothelial Specific Molecule

1 (Esm‐1)/endocan is a secreted glycoprotein highly expressed in kidney glomeruli and lung endothelium and is proposed to disrupt molecular interactions that mediate leukocyte infiltration and anti‐GBM nephritis. To discover the in vivo functional role of Esm‐1 in leukocyte infiltration in anti‐GBM mice, we delivered Esm‐1 plasmid for stable integration to anti‐GBM mice and controls by hydrodynamic tail vein injection. We quantified kidney leukocyte infiltration by separating glomerular and tubulointerstitial compartments, dissociating into single cells, and measuring leukocyte subtypes by flow cytometry. In contrast to i.p. administration of recombinant Esm‐1 which has an abbreviated half‐life in mouse serum (less than 2 hours), we induced ~12‐fold increase in circulating Esm‐1 that persists for 2 weeks compared to control injected mice, by hydrodynamic injection of an Esm‐1‐expressing plasmid (11242 +/− 3324 vs. 958 +/− 188 pg/mL, p<0.05, N=3–5/group). We demonstrate that by flow cytometry, anti‐GBM mice show significantly increased glomerular (3.4 +/− 0.47% vs. 1.1 +/− 0.33%, p < 0.01, N=8/group) and tubulointerstitial (1.4 +/− 0.14% vs. 0.1+/− 0.032%, p < 0.01, N=8/group) CD45+ leukocytes seven days post treatment with anti‐GBM antisera. The increase in CD45+ cells includes increased glomerular (3.4 +/− 0.47% vs. 1.1 +/− 0.33%, p < 0.01) and tubular (1.2 +/− 0.14% vs. 0.1+/− 0.025%, p < 0.01) macrophages. By increasing circulating Esm‐1, we significantly decreased macrophage infiltration in the tubulointerstitium (4.2 ± 1.3% vs. 1.6 ± 0.4%, P < 0.01), but did not influence glomerular macrophage infiltration (2.3 ± 1.2% vs. 1.5 ± 0.2%, P = 0.13). Furthermore, Esm‐1 does not alter kidney neutrophils (glomerular: 0.013 ± 0.007% vs. 0.010 ± 0.006%, p = 0.61; tubulointerstitial: 0.19 ± 0.02% vs. 0.27 ± 0.07%, p = 0.085) or lymphocytes(glomerular: 1.7 ± 0.8% vs. 1.9 ± 0.9%, p = 0.89; tubulointerstitial: 1.9 ± 0.70% vs. 2.2 ± 0.71%, p = 0.64). We also found that inhibition of macrophage infiltration was dependent on glycosylation of Esm‐1. Furthermore, we have generated Esm‐1 knockout mice for complementary studies. We conclude that in contrast to deletion of the inflammatory mediator ICAM‐1, Esm‐1 inhibits inflammation in a tissue and cell‐specific manner. Esm‐1 provides a natural biologic inhibitor of inflammation, and based on its expression pattern, may be a key therapeutic target in pulmonary‐renal syndromes.

Support or Funding Information

1. Larry L. Hillblom Foundation

2. Holmgren Family

3. NIDDK
Racial Differences in CRP Receptor and Influence on eNOS Bioactivity and NO Production in Endothelial Cells
Authors: Aldokhayyil Maitha , Ling Chenyi , Cook Marc , Grimm Heather , Brown Michael D
Published: November 2023

Background

C‐reactive protein (CRP) is an independent biomarker of inflammation and cardiovascular disease (CVD). CRP interacts directly with endothelial cells. CRP decreases endothelial nitric oxide synthase (eNOS) expression and bioactivity and decreases nitric oxide (NO) production. Race/ethnicity is significantly associated with CRP and CVD risks. Thus, the purpose of this study was to assess the racial differences concerning the CRP‐induced biological effects in endothelial cells.

Methods

Human umbilical vein endothelial cells (HUVECs) from four African American (AA) donors and four Caucasian (CA) donors were cultured and incubated with CRP to assess its effects on eNOS bioactivity and NO production measured in cell culture media.

Results

AA and CA HUVECs responded differently to CRP incubation. We report significant increase in FcγRIIB receptor expression under both basal and CRP incubation conditions in AA HUVECs cells (~2‐fold difference, p < .01, Fig 1). This may contribute to the racial differences of CRP‐induced effects on endothelial cells with AA HUVECs showing greater impairment of eNOS expression and bioactivity (~2‐fold decrease, p < .01, Fig 2) and reduced NO production basally (CA: 11.09 ± 1.002 AA: 8.254 ± 0.5285 μmol/L; mean ± SEM, p=0.04). CRP incubation reduced NO production significantly in both AA and CA (CA: 3.947 ± 0.7360 AA: 2.756 ± 0.4368 μmol/L, p <.0001, Fig 3).

Conclusion

A better understanding of the racial differences in endothelial function will help to improve CVD prevention and treatment. The results suggest that the racial differences in CRP‐induced pro‐inflammatory and pro‐atherogenic biological effects on endothelial cells may be partially due to the differential expression of FcγRIIB receptor which may contribute to the disproportionate CVD rates in AA.

Support or Funding Information

ACSM Doctoral Student Research Grant to Chenyi Ling
Influence of Body Fat Distribution in Autonomic Dysfunction of Young Obese Women
Authors: Vicente Wanda Rafaela Pinto Lopes , Fonseca Felipe Xerez Cepêda , da Silva Leslie Virmondes , Hussid Maria Fernanda , Corso Simone Dal , De Angelis Katia , de Paula Vieira Rodolfo , Lopes Heno Ferreira , Consolim‐Colombo Fernanda Marciano , Tinucci Taís , Trombetta Ivani Credidio
Published: November 2023

Obesity impairs autonomic control with an adverse effect on cardiovascular risk. The association of obesity and autonomic dysfunction seems to be dependent on the distribution of body fat. The evaluation of heart rate (HR) at rest and during exercise may reflect autonomic dysfunction. The aim of this study was to evaluate the modulation of HR at rest and during exercise and its association with the body fat distribution in obese young women. We selected 49 young obese women (BMI 30 to 40 kg/m2) with waist circumference (WC) ≥ 88 cm and without comorbidities. They were divided into: with central fat distribution (CF), defined as waist‐to‐hip ratio (WHR) ≥ 0.85 cm (n=26, 34±1.4 y, 33.2±0,5 kg/m2), and with peripheral fat distribution (PF) with WHR < 0.85 cm (n=23, 33±1.4 y, 33.6±0,5 kg/m2). All volunteers were submitted to anthropometric and clinical assessment and to cardiopulmonary exercise test to assess the HR at rest; and changes from rest to peak exercise and during 6 min of recovery. Despite the fat distribution, CF and PF shown similar functional capacity (VO2 peak, 18.4±0.5 vs. 17.9±0.8 mL/kg/min, respectively; p=0.66). However, CF and PF presented diminished functional capacity compared with the estimate functional capacity for similar age and sex (60±2 and 57±3%; p=0.46). Based in the cut‐off values that designated cardiovascular risk, i. e., rest HR >75 bpm and chronotropic reserve (peak HR – rest HR) <89 beats, both obese groups, CF and PF, presented elevated resting HR (89 [82–98] and 86 [81–97] bpm, respectively) and reduced chronotropic reserve (78±3 and 72±4 beats). Furthermore, the group CF (WHR ≥ 0.85) presented reduced attenuation of HR at 1st min of recovery compared with PF (14±1 vs. 20±2 beats, p=0.044). In conclusion, our data suggest that young obese women had impaired sympatho‐vagal balance, observed by resting HR and chronotropic reserve during maximal progressive exercise test. The central body fat distribution potentiates the vagal dysfunction, characterized by reduced attenuation of HR at 1st min of recovery after maximal exercise test.
Potential sympathetic activation in response to a training macrocycle is associated sport injuries incidence in competitive sprint swimmers
Authors: Oliveira‐Junior Silvio A , Lima‐Borges Dayanne S , Vanderlei Luiz Carlos M , Barbosa Fernando S S , Okoshi Marina P , Okoshi Katashi , Martinez Paula F
Published: November 2023

Although overtraining has been associated with disturbed cardiac autonomic modulation and sport injuries incidence, these issues are poorly understood in swimmers. This study analyzed heart rate variability (HRV), stress/recovery relationship, and sport injuries incidence during a training periodization of teenager swimmers of different modalities.

Methods

Thirty teenager swimmers (12 until 17 years‐old) were divided in two groups, according swimming modality: Sprint (n=17) and Endurance (n=13). Subjects were evaluated during a training periodization with twenty weeks of duration, scheduled on three stages: general period (GP, 8 weeks), technical preparation (TP, 8 weeks), and competitive period (CP, 4 weeks). To prospectively analyze HRV, time and frequency domain measures were obtained at the end of each training period. Besides sport injuries incidence, stress/recovery states in athletes were continuously analyzed with the Recovery‐Stress‐Questionnaire of Athletes. All proceedings were developed in initial moment and in the end of each periodization step. HRV results were analyzed by ANOVA and Bonferroni's test; sports injuries incidence was analyzed by Student t‐test.

Results

Sprint showed progressive reduction in HRV, supported by significant reductions in multiple time‐domain results (SDNN, RMSSD, and pNN50) between GP and CP. Additionally, regarding responses in the frequency domain within Sprint group, participants have also presented increased values of low frequency (GP, 48.5±4.3; CP, 58.5±4.0 nu; p=0.022), and reduced high frequency (GP, 51.4±4.3; CP, 40.6±4.0 nu; p=0.012) in competitive period compared to general preparation period; Endurance exhibited unchanged HRV results during all training macrocycle. Stress/recovery monitoring was affected by the swimming training periodization in both swimming groups (p<0.05); both differences between recovery and stress scales levels within global and sport specific contexts have increased at the end of the TP and CP, respectively, compared to general preparation period. Moreover, sprint swimmers showed higher measures of incidence of sport injuries than endurance athletes (Sprint, 0.0214±0.0068; Endurance, 0.0136±0.0050 cases/1000 hours; p<0.05).

Conclusion

Sprint training was associated with probable activation of the sympathetic nervous system and decreased heart rate variability, besides higher incidence of sport injuries, in comparison to endurance swimming during a training macrocycle.

Support or Funding Information

Financial support: CAPES; FUNDECT/MS
Disruption of Adenylyl Cyclase Type 5 Eliminates Gender Differences in Exercise Capacity
Authors: Rynecki Nicole Danielle , Guers John , Zhang Jie , Vatner Dorothy , Vatner Stephen
Published: November 2023

It is well established that enhanced exercise capacity is related to protection from cardiovascular disease, obesity and contributes to healthy aging. Unlike larger animals and humans, where male animals have a higher exercise capacity, female mice have generally shown to have a greater basal exercise capacity and a greater threshold for exercise training improvement. Relatively few studies have examined gender differences in models with enhanced exercise capacity. Since male mice with disruption of adenylyl cyclase type 5 (AC5) have greater exercise capacity than their wild type (WT) littermates, the goal of this investigation was to determine if female AC5 knock out (KO) mice have even greater treadmill exercise capacity than their male littermate. Untrained WT female mice exhibited 21 ± 4% greater maximal exercise capacity for distance (475 ± 19 m) than age‐matched males (males: 389 ± 19 m; p<0.05). In part this could be explained by lower weight of females, although cardiac work was also increased by 13 ± 3.5% in untrained females. When mice were exercise‐trained for 4 weeks by running for 1 hour per day, the exercise‐trained mice had a similar gender disparity with females running 23 ± 8.5% greater distance than age‐matched trained males. We then examined exercise capacity in male and female AC5 KO mice. As we found before, male AC5 KO mice without exercise training performed better (835 ± 32 m) than even female exercise‐trained WT (716 ± 42 m). Surprisingly, female AC5 KO mice performed exercise no better (863 ± 44 m) than the male AC5 KO mice, and work performed was no longer greater in females (27.8 ± 1.4 J) than males (27.9 ± 1.3 J). These data suggest that a cyclic AMP mechanism may be involved either in these gender differences or in the ability to attain maximal exercise capacity.

Support or Funding Information

This study is supported by NIH grant: R01 HL106511.
Exercise combined with low‐level GABAA receptor inhibition up‐regulates the expression of neurotrophins in the motor cortex
Authors: Takahashi Kazuma , Maejima Hiroshi , Ikuta Gaku , Asaka Tadayoshi , Mani Hiroki
Published: November 2023

Neurotrophins play a crucial role in neuroplasticity, neurogenesis, and neuroprotection in the central nervous system. Exercise is known to increase the expression of brain‐derived neurotrophic factor (BDNF) in the brain. Several animal studies have evaluated the tonic inhibition of GABAergic synapses to enhance hippocampal plasticity as well as learning and memory, whereas the effects of GABAergic inhibition on plasticity in the cerebral cortex related to motor learning are not well characterized. The objective of the present study was to examine the interactive effect of low‐level GABAA receptor inhibition and exercise on the expression of neurotrophins including BDNF in the murine motor cortex. ICR mice were randomly distributed among 4 groups based on two factors of GABAA receptor inhibition and exercise, i.e. a control group, an exercise group, a bicuculline group, and an exercise plus bicuculline group. We administered GABAA receptor antagonist, bicuculline intraperitoneally to the mice (bicuculline and exercise plus bicuculline group) at a non‐epileptic dose of 0.25 mg/kg, whereas the mice (exercise and exercise plus bicuculline group) were exercised on a treadmill for 1 hour every day. After two week intervention, the expression of mRNA and protein abundance of neurotrophins in the motor cortex was assayed using Real time PCR and ELISA. BDNF gene expression was significantly increased by approximately 3‐fold in the bicuculline group relative to the control, exercise, and bicuculline plus exercise groups. Protein abundance of BDNF expression was significantly increased by approximately 3‐fold in the bicuculline plus exercise group relative to other groups. Therefore, the present study revealed that combined GABAA receptor inhibition and moderate aerobic exercise up‐regulated BDNF protein expression in the motor cortex without producing side effects on motor or cognitive functions. Alterations in BDNF expression could positively contribute to plasticity by regulating the balance between EPSPs and IPSPs in the motor cortex and thus provide a more appropriate neuronal condition for motor learning and recovery.

Support or Funding Information

This work was supported by JSPS KAKENHI Grant 24500619.
Influence of Exercise and Maternal Lipids during Pregnancy on Neonatal Size
Authors: May Linda E , Moyer Carmen M , Newton Ed , Strickland Diana , Isler Christy , Haven Kelley , DeVente Jim , Chasan‐Taber Lisa , Kelley George , Fang Xiangming
Published: November 2023

We hypothesized that exercise during pregnancy and maternal BMI will be significant predictors of neonatal size. This hypothesis was tested by analyzing maternal and neonatal measurements. Women were exercise trained throughout pregnancy for 20 wks at moderate intensity for 150 min/wk. Maternal pre‐pregnancy BMI was self‐reported; and lipids were measured before and after exercise intervention. Fetal (36 wk) weight was acquired via ultrasound and neonatal measures were acquired via birth records. Data from 36 uncomplicated pregnancies (27 exercise,

9 control) were analyzed. Although exercise is not a significant predictor of neonatal size, exercise intervention changed maternal lipid levels. We found that a significant predictor of neonatal BMI is maternal LDL levels after exercise intervention training. A significant predictor of neonatal ponderal index is maternal triglycerides and LDL levels after exercise intervention training. Surprisingly, we have found exercise during pregnancy only indirectly influences neonatal measures by changing maternal lipid levels. These results suggest maternal lipids influence neonatal size, but exercise during pregnancy can help regulate this influence. These data further support the benefits of exercise during pregnancy on positive neonatal outcomes.

Support or Funding Information

ECU, 15GRNT24470029
Enhanced microvascular function in the cutaneous circulation with platelet inhibition is not related to alterations in blood viscoelastic properties
Authors: Garner Tyler Bruce , Dahmus Jessica , Manning Keefe , Alexander Lacy
Published: November 2023

Platelet inhibition with aspirin and/or clopidogrel are part of a comprehensive strategy for the primary and secondary prevention of cardiovascular disease, respectively. In the cutaneous microcirculation, treatment of clopidogrel (CLO) but not aspirin (ASA) increases cutaneous microvascular relaxation in response to reactive hyperemia. CLO is mechanistically distinct from ASA in that it works through inhibiting the platelet P2Y12 receptor and may change blood viscosity and thus the shear stimulus on the microcirculation. In this study, we sought to determine if platelet inhibition with CLO changes whole blood viscoelastic properties and is related to increased microvascular function. Nine middle‐aged healthy subjects (5 men, 4 women; 56 ± 1 yr) participated in a randomized, double blind, placebo‐controlled crossover experiment. Treatment phases included a sucrose placebo, CLO (75 mg; Bristol‐Myers Squibb), and ASA (81 mg; Bayer) for 7–10 days with a two week washout period between each treatment. On the final day of treatment, laser Doppler flux (LDF) was measured during a standardized 5 minutes reactive hyperemia protocol and area under the curve (AUC) and total hyperemic response (THR) were calculated and normalized to maximal cutaneous vascular conductance (%CVCmax: 43°C and 28 mM sodium nitroprusside). Blood viscoelasticity was measured using a Vilastic‐3 viscoelasticity analyzer at 2 Hz across a physiologically relevant shear rate range of 25 to 1000 s−1. Blood temperature was maintained at time of draw using a heat exchanger. CLO and ASA did not change hematocrit relative to the placebo control (41.6 ± 0.9, 41.9 ± 0.6, and 41.5 ± 0.7 % respectively). AUC and THR increased in the CLO trial (AUC = 3783 ± 342, THR = 2306 ± 266 %CVCmax * s; P<0.0001 vs. placebo) but there was no difference between ASA (AUC = 3101 ± 325, THR = 1695 ± 197 %CVCmax * s) and placebo (AUC = 3000 ± 283, THR = 1675 ± 170 %CVCmax * s, P>0.05) Apparent kinematic viscosity and elasticity was unchanged in either CLO or ASA treatment relative to placebo across the entire range measured when normalized to a hematocrit of 45 %. 7–10 days of CLO or ASA does not change hematocrit or blood viscoelastic properties in healthy humans and is not related to functional measures of microvascular function (p>0.05). Improvements in cutaneous microvascular function by CLO is not a result of shear‐stress induced vasodilation, further indicating that CLO may alter sensory nervous activity and/or endothelium‐derived hyperpolarizing factor mechanisms.

Support or Funding Information

NIH R01 HL093238‐07
Effects of Glycyrrhetic Acid and other Chemical Components of Shakuyakukanzoto on Cutaneous Microcirculation in Humans
Authors: Dillon Gabrielle A. , Ranadive Sushant M. , Joyner Michael J. , Eugene Andy R. , Tasaki Kazuyo M. , Noble Denis M.
Published: November 2023

The purpose of this study was to explore dose dependent vasodilation responses of the individual compounds of Shakuyakukanzoto (SKT), a 1:1 combination of extracts from Paeony and Licorice roots: glycyrrhetic acid (GA), paeoniflorin (PF), and isoliquiritigenin (ISO). 20 young, healthy participants (13M/7W) had four intradermal microdialysis fibers placed in the forearm skin for local delivery of: 1) control (diluent), 2) GA, 3) PF, or 4) ISO at doses of 1, 10, 50, or 100 μm. Cutaneous red cell flux, an index of skin blood flow, was measured by laser‐Doppler flowmetry. Blood pressure (BP) was monitored continuously during fixed measurement periods via finger photo‐plethsmography (Finapres). Cutaneous vascular conductance (CVC) was derived as red cell flux divided by BP and was normalized as a percentage of baseline (%CVCbl, saline at 4 μl/min) and the maximum CVC (%CVCmax, 28mM sodium nitroprusside at 4 μl/min, local temperature 43°C). Mean CVC did not statistically differ between baseline and individual compound plateau (average of last 5 minutes of infusion) at any dose. The peak flux was significantly higher from baseline at doses 50 and 100 μm for control (56.17±13.32 vs. 96.73±20.32 and 44.64±5.68 vs. 80.21±9.54), PF (62.70±10.09 vs. 115.72±16.16 and 62.37±16.2 vs. 150.21±34.26), GA (48.37±4.41 vs. 71.76±7.16 and 58.36±13.68 vs. 91.51±3.41), and ISO (96.50±23.20 vs. 128.57±27.90 and 44.95±8.78 vs. 91.18±20.37) (p<0.05). However, peak CVC was significantly higher only for GA at dose 50 μm, as well as for control and PF at dose 100 μm compared to their respected baselines (GA: 0.60±0.06 vs. 1.01±0.11, control: 0.61±0.09 vs.1.55±0.61, PF: 0.81±0.20 vs. 1.30±0.30, p<0.05). There were no other significant differences between the control and the compounds for change in CVC from baseline to peak (ΔCVC), %CVCbl, or %CVCmax. There were no significant differences between doses 1, 10, or 50 as compared to 100 μm for other variables. These results suggest that the doses may be lower or below the threshold to cause a vasodilatory effect. Future studies that investigate higher doses of these compounds may be needed.

Support or Funding Information

The University of Oxford Systems Biology Project sponsored by Tsumura.
Carotid Vascular Blood Flow in Individuals with Down Syndrome Following Low Body Negative Pressure Challenge
Authors: Wee Sang Ouk , Rosenberg Alexander J. , Kanokwan Bunsawat , Griffith Garett , Baynard Tracy , Fernhall Bo
Published: November 2023

Individuals with Down Syndrome (DS) exhibit autonomic dysfunction with reduced sympathetic activity, which may cause reduced aerobic capacity and alterations in peripheral blood flow. Carotid vascular function has been considered as a marker of future cardiovascular events. However, changes in carotid blood flow and vascular conductance in response to sympathoexcitation are not well characterized in persons with DS, carotid stiffness responses to exercise differ between individuals with DS and controls.

Purpose

To examine the differences in hemodynamics, carotid vascular reactivity and blood flow following sympathoexcitation using lower body negative pressure (LBNP) in individuals with and without DS.

Methods

13 young (18 < age <40 yrs) individuals with and without DS (DS=6) participated in this study. Changes in hemodynamics and carotid vascular reactivity (BP, carotid diameter, carotid flow and vascular conductance) were measured before, during and after LBNP (−20 mmHg).

Results

Baseline hemodynamics where not different between the group with DS and controls. The group with DS showed an altered response in conductance to LBNP, when compared to controls with large effect size (η2 = 0.138). In addition, carotid blood flow exhibited a large effect size (η2 = 0.242) for a group interaction. During recovery, the group with DS showed an increase in BF, whereas control group exhibited decrease in BF. These changes occurred without differential changes in carotid diameter and blood pressure.

Conclusions

Our results demonstrate the tendency of reduced vascular reactivity in individuals with DS to sympathoexcitation, demonstrated by large effects sizes. Our findings indicate altered blood flow control in persons with DS, attributable to autonomic dysfunction. Larger sample sizes will be needed to confirm these findings.

DS (N = 6)
Control (N = 7)

Baseline
LBNP (−20mmHg)
Recovery
Baseline
LBNP (−20mmHg)
Recovery

Carotid SBP (mmHg)
118 ± 5
111 ± 4
119 ± 5
126 ± 5
114 ± 4
121 ± 4

Carotid DBP (mmHg)
69 ± 4
68 ± 3
68 ± 3
76 ± 3
73 ± 2
77 ± 3

Carotid MAP (mmHg)
87 ± 5
84 ± 3
88 ± 4
96 ± 4
90 ± 3
95 ± 4

Carotid Blood Flow (ml/min)
378.0 ± 110.3
394.1 ± 115.3
399.9 ± 112.2
539 4 ± 102.1
552.6 ± 106.8
500.1 ± 103.9

Carotid Vascular Conductance (ml/min/100mmHg)
25.3 ± 3.6
29.0 ± 4.6
28.1 ± 4.0
32.0 ± 3.3
35.1 ± 3.8
30.7 ± 3.6

Mean ± SEM
Nasal Administration of Diesel Exhaust Particles Does Not Evoke Dysfunction or Initiate Autophagy in Murine Femoral Arteries
Authors: Cho Jaemin , Kim Ji‐Seok , Lewis Joshua B , Reynolds Paul R , Bikman Benjamin , Symons J David
Published: November 2023

Fine particulate matter (PM2.5) from air pollution is associated with cardiovascular morbidity and mortality. Combusted diesel exhaust emissions are the major source of PM2.5. Upon inhalation of diesel exhaust particles (DEPs), an inflammatory response in the lung could release prothrombotic and inflammatory cytokines into the circulation. In addition, the nanometer size of DEP has potential to allow transportation to and translocation across the respiratory epithelium and into the circulation. In both cases, DEP could act on perfusion territories that are distal to the lung and evoke dysfunction. Recent reports indicate that impaired endothelial cell nitric oxide (NO) bioavailability upon exposure to DEPs might be secondary to exaggerated reactive oxygen species (ROS) generation. ROS are known activators of autophagy in a number of cell types. We hypothesized that exposure to DEPs evokes dysfunction and initiates autophagy in murine femoral arteries. Four‐month old female C57Bl6 mice received 10 exposures to 0 ng (CON, n=5) or 35 ng diesel exhaust particles (DEP, n=5) over 14 days via a nose‐only nebulization unit. After the last treatment arteries were prepared to assess autophagy‐related protein expression via immunoblotting, or vascular reactivity via isometric tension procedures. Internal diameter (180 ± 9 and 190 ± 13 μm) and Lmax tension (738 ± 10 and 731 ± 38 mg) was similar in femoral arteries (n=5 per group) from CON and DEP animals, respectively. Tension development to potassium chloride (KCL; 10–100 mM) and phenylephrine (PE, 10−8–10−5 M) was similar between groups, indicating that non‐receptor mediated and receptor‐mediated vasocontractile mechanisms, respectively, were intact. After precontraction using PE, relaxation to the endothelium‐dependent vasodilator acetylcholine (ACh; 10−8–10−6 M), and the endothelium‐independent vasodilator sodium nitroprusside (SNP, 10−9–10−4 M), was similar between groups. Indices of autophagy were assessed in homogenates of aorta and iliac artery from the same animals. Autophagy related gene 3 (Atg3) is the phosphatidylethanolamine‐transferase that performs the final lipid‐conjugation modification of Atg8 (LC3) required for its association with phagophore membranes i.e., completes the conversion of LC3I to LC3II. LC3II:GAPDH, LC3II:LC3I, Atg3:GAPDH, and Atg7:GAPDH were similar in homogenates from CON and DEP animals. At least in the context of our experimental conditions, exposure to DEPs does not alter femoral artery function or arterial (aorta/iliac artery) autophagy.
Aerobic training restores endothelial function in intrauterine growth restricted rats: Possible involvement of eNOSThr495 phosphorylation
Authors: Oliveira Vanessa , Victorino Livia , Silva Sebastião Donato , Fernandes Tiago , Akamine Eliana , de Carvalho Maria Helena Catelli , de Oliveira Edilamar Menezes , Michelini Lisete Compagno , Franco Maria
Published: November 2023

Purpose

To evaluate the effects of aerobic training on vascular reactivity in adult male offspring submitted to intrauterine growth restriction.

Methods

Procedures approved by Ethics Committee of UNIFESP (836880). Pregnant Wistar Rats were submitted to Ad libitum or 50% of Ad libitum diet throughout gestation. At birth, pups were weighted. Adult Male offspring of both groups were assigned to Sedentary Control (SC), Sedentary Restricted (SR), Trained Control (TC) and Trained Restricted (TR). After AT (10 weeks, 5 days/week, 1h/day, 50–60% of maximum exercise capacity) femoral artery was cannulated to register mean arterial blood pressure (BP) and heart rate (HR). The vasodilatation endothelium‐dependent and endothelium‐independent were assessed by concentration‐response curves to Acetylcholine (ACh:10–9M‐3X10‐5M) and Sodium Nitroprusside (SNP:10‐9M‐10‐6M), respectively in thoracic aorta rings. In addition, we evaluated in thoracic aorta: protein expression of total eNOS, p‐eNOSSer1177, and p‐eNOSThr495 using western blotting, and nitric oxide concentration by NO analyzer. Results are shown as mean ± EPM, test t de student or Two‐way ANOVA following Bonferroni were used.

Results

IUGR was confirmed by birth weight (Control:7.01±0.34g vs. Restricted:4.3±0.08g). AT‐restored BP in TR (SC:118±3mmHg; TC:110±2 mmHg; SR:129±2 mmHg; TR:110±4 mmHg) and lead to a reduction in HR (SC:355±13bpm; TC:321±4 bpm; SR:343±4 bpm; TR:309±7 bpm). AT normalized the relaxation to ACh (SC:92.18±2.7%; TC:90.05±2.04%; SR:65.04±4.4%; TR:93.35±1.7%) in aorta from IUGR rats, whereas vasodilatation to SNP was not altered (SC:98.45±2.38%; TC:97.84±1.68%; SR:93.97±2.64%; TR:97.64±0.90%). p‐eNOS Ser1177 expression was similar among groups (data not show). However, AT‐reduced the increased p‐eNOSThr495 found in aorta from RT group (SC:0.53±0.03; TC:0.51±0.10; SR:0.86±0.06; TR: 0.59±0.04). Nitric oxide concentration was increased in RT (SC: 426.2±63.03μM/mg; TC: 349±46 μM/mg; SR: 217.8±18.22 μM/mg; TR: 355±53 μM/mg).

Conclusion

Our results indicated that AT‐restores endothelial function in intrauterine growth restricted rats, in part due to reduction in p‐eNOSThr495 expression associated to increase in nitric oxide concentration in thoracic aorta.

Support or Funding Information

FAPESP: 2013/00311‐6
Activation of Protease‐Activated Receptor 2 Directly Mediates Cutaneous Vasodilatation but Not Sweating in Humans In Vivo: Roles of Nitric Oxide Synthase and Cyclooxygenase
Authors: McNeely Brendan Douglas , Fujii Naoto , Zhang Sarah Y. , Daquan Mercy O. , Kenny Glen P.
Published: November 2023

Protease‐activated receptor 2 (PAR2) is present in the endothelial cells of skin microvessels and eccrine sweat glands in humans. Notably, this receptor has been shown to play a role in the vascular control of larger arteries and the control of epidermal permeability. However, it remains unclear if PAR2 functionally contributes to the regulation of cutaneous blood flow and sweating in humans. Therefore, the objective of the current study was to determine whether the activation of PAR2 directly stimulates cutaneous vasodilation and sweating through nitric oxide synthase (NOS) and cyclooxygenase (COX) mediated mechanisms. In twelve young males (29±5 years), cutaneous vascular conductance (CVC, measured via laser‐Doppler perfusion units/mean arterial pressure) and sweat rate (measured via ventilated capsule) were evaluated at four intradermal microdialysis forearm skin sites that were constantly perfused with either 1) lactated Ringer (Control), 2) 10 mM Nω‐nitro‐L‐arginine (NOS inhibitor), 3) 10 mM ketorolac (COX inhibitor), or 4) a combination of 10 mM Nω‐nitro‐L‐arginine + 10 mM ketorolac. The PAR2 agonist (SLIGKV‐NH2) was co‐administered at all sites in a dose‐dependent fashion (0.06, 0.18, 0.55, 1.66, and 5 mM, each for 25 min). Throughout the protocol, participants rested in a semi‐recumbent position in a thermoneutral room (23°C). Responses were compared at baseline and the last 5 min of each dose administered. The highest dose of SLIGKV‐NH2 (5 mM) increased CVC from baseline (BL) at the Control site (BL: 15 ± 8% CVCmax, 5 mM: 37 ± 22% CVCmax; P ≤ 0.01). This increase in CVC associated with PAR2 activation was attenuated by NOS inhibition with or without simultaneous COX inhibition (Control: 37 ± 22%CVCmax, NOS inhibition: 25 ± 16% CVCmax, NOS+COX inhibition: 23 ± 16% CVCmax; both P ≤ 0.05). However, COX inhibition alone had no effect on the PAR2 mediated increase in CVC at all doses (all P > 0.05). No increase in sweat rate was measured at any administered dose of SLIGKV‐NH2 irrespective of the agent co‐administered (all P > 0.05). In conclusion, we show that in normothermic resting humans, in vivo activation of PAR2 directly mediates cutaneous vasodilation through NOS‐dependent mechanisms without any contribution of COX mediated pathways. Alternatively, the same activation of PAR2 does not lead to increases in forearm sweat rate.

Support or Funding Information

This study was supported by the Natural Sciences and Engineering Research Council of Canada (Discovery grant, RGPIN‐06313‐2014; Discovery Grants Program ‐ Accelerator Supplement, RGPAS‐462252‐2014; funds held by Dr. Glen P. Kenny).
Impact of Sleep Disordered Breathing on Carotid Body Size
Authors: Petersen‐Jones Humphrey G. , Welch Brian T. , Eugene Andy R. , Brinjikji Waleed , Kallmes David F. , Curry Timothy B. , Joyner Michael J. , Limberg Jacqueline K.
Published: November 2023

Post‐mortem analyses have identified carotid body hypertrophy in conditions of chronic hypoxemia, including sleep apnea; however, post‐mortem assessment limits the clinical relevance of such findings. We tested the hypotheses that: 1) carotid body size can be detected in living individuals by computed tomographic angiography (CTA), and 2) patients with sleep disordered breathing [Apnea Hypopnea Index (AHI) ≥ 30 events/hour] exhibit larger carotid bodies than those without sleep disordered breathing (AHI < 5 events/hour). A chart review was conducted from patients seen at the Mayo Clinic between January 2000 and February 2015 who had undergone neck CTA and polysomnography. From an initial pool of 583, 109 patients met our strict inclusion criteria. Widest axial measurements of the right and left carotid bodies were performed independently by two radiologists blinded to condition and average carotid body size was calculated for each patient of interest. Carotid body identification was possible in 81% of patients. Intra‐class correlation coefficients ranged from 0.93 to 0.95 (right carotid body: 0.93; left: 0.94; average: 0.95). From subjects with identifiable carotid bodies, widest axial measurements were greater in patients with high AHI (n=32; right: 2.9±0.2mm, left: 3.1±0.2mm, average: 3.0±0.1mm) compared to patients with low AHI (n=46; right: 2.5±0.1mm, left: 2.7±0.1mm, average: 2.6±0.1mm; p=0.04, p=0.04, p=0.02, respectively). Because participants in the high AHI group were significantly older than those in the low AHI group (65±2 years vs. 50±2 years; p<0.01), an analysis of covariance was performed to control for the influence of age on carotid body size. After adjusting for age, no differences in carotid body size were observed between the patient groups (p=0.45, p=0.59, p=0.54 for right, left, and average carotid body, respectively). Main findings are two‐fold: 1) carotid body size can be identified by CTA in approximately 80% of patients with good inter‐observer agreement, and 2) adults that exhibit sleep disordered breathing do not have larger carotid bodies when compared to controls, after adjusting for age.

Support or Funding Information

This work was supported by the National Institutes of Health [grant numbers T32 GM008685 (ARE), R01 DK090541 (MJJ)].
The Brain, Not the Kidney, is the Source of Erythropoietin in Response to Hypoxic Hypoxia
Authors: Allwood Melissa A , Romanova Nadya , Brunt Keith R , Simpson Jeremy A
Published: November 2023

Erythropoietin (EPO), the principle regulator of erythropoiesis, is central to our understanding of tissue hypoxia. For over a century, the kidney has been regarded as the primary site of EPO production. While multiple extra‐renal sources have been identified, their physiological significance remains largely uninvestigated. Further, studies investigating the source of EPO production use severe (non‐survivable) levels of hypoxia, despite that levels encountered in most pathophysiological states are mild to moderate. The assumption being that the response to less severe hypoxic stimuli is linearly scaled. Our objective was to investigate whole‐body EPO production in response to clinically‐relevant levels of hypoxia. We performed a multi‐organ, temporal analysis of EPO expression in response to moderate (FIO2 = 0.15) and severe (FIO2 = 0.09) hypoxic hypoxia. Using the Cre‐lox system, we proved that the brain, and not the kidney, was the sole responder to moderate hypoxia and the primary responder to severe. Thus, the erythropoietic response to hypoxia involves multiple tissues in a degree‐ and duration‐dependent manner with the brain as the first and primary site of EPO production. These data identify a critical shift in our understanding of oxygen carrying capacity in hypoxic hypoxia from peripheral to central regulation.

Support or Funding Information

This work was funded in part by grants from the Canadian Institutes of Health Research (JAS; Grant # MOP111159) and the Natural Sciences and Engineering Research Council of Canada (JAS). JAS is also a new investigator with the Heart and Stroke Foundation of Ontario.
Catecholamine secretion from the adrenal medulla is blunted in high‐altitude deer mice (Peromyscus maniculatus)
Authors: Scott Angela L , Pranckevicius Nicole A , Patal Paras , Nurse Colin A , Scott Graham R
Published: November 2023

Chronic hypoxia stimulates the sympathetic nervous system and adrenal catecholamine (CAT) secretion, which helps to protect vital organs during low oxygen conditions. However, chronic sympathetic activation has also been associated with systemic and pulmonary dysfunction related to the extended elevation of circulating CATs. In this study, we compared the effects of chronic hypoxia exposure (6–8 weeks, 12 kPa O2) on CAT secretion from adrenomedullary chromaffin cells (AMCs) obtained from low‐versus high‐altitude populations of deer mice. Under normoxic conditions, acetylcholine released from the splanchnic nerve acts on nicotinic acetylcholine receptors (AChR) in the adrenal medulla, and results in CAT secretion into the circulation. Using carbon fiber amperometry, CAT secretion was measured in thin adrenal slices exposed to the AChR agonist, nicotine (10 or 50 uM). CAT secretion in response to low doses of nicotine (10 uM) was blunted in AMCs of lowland mice after chronic hypoxia exposure, but restored in hypoxic lowlanders when higher concentrations of nicotine (50 uM) were applied. In comparison to lowlanders CAT secretion from AMCs of the highland population, acclimated to either normoxic or hypoxic conditions, was significantly lower in response to both high and low doses of nicotine. The prominent reduction of CAT secretion in the adrenal medulla of the highland population across both environmental conditions suggests an alteration in nicotinic AChR function and/or a reduction in CAT secretory function in these mice. Further examination of AMCs in low‐versus high‐altitude deer mice revealed lower expression of key enzymes in catecholamine synthesis (particularly DOPA decarboxylase), as well as lower plasma levels of adrenaline, in the highland population. Our findings suggest that high‐altitude adaption in deer mice suppresses catecholamine secretion from the adrenal gland in hypoxia, which appears to involve a reduction in catecholamine synthesis and storage.

Support or Funding Information

Funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada. Angela L Scott is a NSERC Postdoctoral Fellow.
Norepinephrine (NE) and intermittent hypoxia (IH) impact short term synaptic plasticity in the hippocampus
Authors: Barnard Jasmine E , Khuu Maggie A , Garcia Alfredo J
Published: November 2023

Conditions such as sleep apnea can produce states of increased noradrenergic tone that coincide with bouts of IH. A previous report indicates that the influence of IH on neurophysiology is changed by increased noradrenergic tone. The objective of this ongoing study is to determine how acute IH (AIH) and NE affect short‐term synaptic plasticity (i.e., paired pulse facilitation, PPF) in the CA1 neuronal population. We hypothesize that NE changes PPF following AIH. To test this hypothesis, extracellular recordings of electrically evoked field excitatory postsynaptic potentials were made from the CA1 neuronal population within mouse hippocampal brain slices. A paired pulse protocol using an interpulse interval (20ms to 500ms) was performed before and following AIH. AIH consisted of three intervals of hypoxia (95% N2, duration=180 sec) separated by recovery periods (95% O2, duration=180 sec). While 2 mircoM NE did not affect PPF (n=3), PPF was augmented following AIH (n=4). However, combined, NE/AIH suppressed PPF (n=3). Our findings, to date, suggest that NE alters how IH affects short term plasticity in the CA1 neuronal population.
The Effects of Sildenafil, phosphodiesterase 5 inhibitor, on the Expression of α and β Myosin Heavy Chains in Hypoxia induced Right Ventricular Hypertrophy in Mice
Authors: Khatib Said Younes , AlJanabi Mukhallad Mohammed
Published: November 2023

Introduction

Myosin heavy chains are known to be the main contractile protein in muscles. It is present in the cardiac muscle in two forms alpha (α), and beta (β). The contractile properties of the cardiac muscle are determined by the types of myosin heavy chain (MHC) present in the muscle. The expression of these MHCs can be altered by many physiological and pathological conditions. In this study we investigated the effect of sildenafil on MCHs isoforms in hypoxia induced right ventricular hypertrophy in mice.

Method and results

Right ventricular hypertrophy was induced by exposing the animals to low oxygen tension (11%) in normobaric chamber for 20 days. 32 mice were distributed randomly into: 10 as control (C). 10 were exposed to hypoxia for 20 days without sildenafil treatment (I) and 12 were given sildenafil orally at dose of 30 mg.Kg‐1.day‐1 while they were exposed to hypoxia for 20 days (II). MCHs isoforms were detected using two ELISA kits containing antibodies against α and β MHCs. Compared to control group C, mice exposed to hypoxia (group I) showed a significant increase in right ventricle weight to body weight mg/g ratio, (0.89±0.13 in group C and 1.3± 0.3 in group I, P> 0.001) but significant changes in ratio of group II, (0.91+ 0.15). Expression of β MHC isoform was significantly decreased in mice group I (P>0.001), while mice exposed to hypoxia and treated with sildenafil showed significant shift of MHC towards β isoform (P>0.000). Hypertrophied right ventricle expresses more α myosin heavy chain and this is beneficial to the heart since hearts with more α MHC have more ATPase activity and powerful and fast contraction.

Conclusion

sildenafil reduced hypoxia induced right ventricular hypertrophy and caused a shift in MCH towards β form which makes the heart contraction more economical (i.e using less ATPase).