bluuebunny/crossref_metadata_2025 huggingface dataset:
N‐Acetyl‐Seryl‐Aspartyl‐Lysyl‐Proline (Ac‐SDKP) Prevents the Progression of Renal Dysfunction in Mice with Lupus (MRL/lpr)
Authors: LIAO TANG‐DONG , NAKAGAWA PABLO , D'AMBROSIO MARTIN , RHALEB NOUR‐EDDINE , YANG XIAO‐PING , CARRETERO OSCAR
Published: June 2021

Ac‐SDKP is a natural regulator of hematopoiesis. We have reported that Ac‐SDKP attenuates inflammation and fibrosis in autoimmune myocarditis. In this study, we tested the hypothesis that Ac‐SDKP prevents renal inflammation and fibrosis in normotensive mice with autoimmune lupus (MRL/lpr). Ac‐SDKP (800μg/kg/day) or vehicle were infused via osmotic mini‐pump starting at 12 weeks and continued until 32 weeks of age. The MRL/lpr‐given vehicle develops severe albuminura, renal inflammation and fibrosis, and decreased glomerular filtration rate (GFR) without changing blood pressure. Treatment with Ac‐SDKP ameliorates all of these pathological changes. Furthermore, Ac‐SDKP also attenuates the facial rash developed in the MRL/lpr mice. These findings suggest that Ac‐SDKP treatment may be a novel and useful therapeutic strategy for the treatment of progressive systemic lupus erythematosus diseases.

Parameters
Ctrl + Vehicle
Ctrl + Ac‐SDKP
MRL/lpr + Vehicle
MRL/lpr + Ac‐SDKP

Albuminuria (ug/24 hrs)
16.6 ± 3.6
17.3 ± 3.0
469 ± 107**
81.7 ± 14.5§§

GFR (μl/min/100mg kidney weight)
115 ± 19
108 ± 25
19 ± 7**
64 ± 14§

Renal collagen content (μg/mg dry weight)
19.4 ± 2.3
20.7 ± 2.2
33.8 ± 3.6*
22.0 ± 0.8§

Renal macrophage infiltration ( #/mm2)
174 ± 12
146 ± 10
543 ± 53**
163 ± 20§§

Facial rash scores
1.2 ± 0.1
1.6 ± 0.3
2.9 ± 0.4**
1.7 ± 0.2§§

p < 0.05,

p < 0.01, MRL/lpr + Veh vs Ctrl + Veh;

p < 0.05,

p < 0.01, MRL/lpr + Veh vs MRL/lpr + Ac‐SDKP
Estrogen supplementation increases renal sodium absorption during high salt consumption in female and male mice
Authors: Rouch Al , Kudo Lucia , Nguyen Sarah , Nadeem Maria
Published: June 2021

The purpose of this study was to determine the effects of estrogen supplementation on the renal excretion of Na+ (UNa· V) in CD‐1 mice. Two studies were conducted – one with females and one with males. Female groups (n=4/group) included normal (NF), ovariectomized implanted with a placebo pellet (OP), and ovariectomized with a 0.1 mg estrogen pellet (OE). Male groups included normal (NM), castrated with placebo pellet (CP), and castrated with estrogen pellet (CE). Pellets were purchased from Innovative Research of America (Sarasota, FL). Mice in metabolic cages consumed 1% salt diet for 5 days, 4% salt for the next 15 days, and 1% salt for the final 5 days. No differences occurred during the 1% salt periods. Average UNa· V (μEq/day ± se) for the 4% salt periods were: females: 1652±92, 2011±82*, 1457±106† (NF, OP, OE, respectively); and males: 1976±163, 2154±153, 1312±100*† (NM, CP, CE, respectively) (*p<.01 compared to NF or NM; † ‐ p<0.01 compared to OP or CP). We conclude that estrogen administration yields significant renal Na+ absorption during high salt loads in female and male mice. Results suggest a sex difference in Na+ excretion during high salt consumption.
Etanercept improves glucose intolerance and dyslipidemia in insulin‐resistant rats
Authors: Lee Andrew , Rodriguez Ruben , Ortiz Rudy , Ryan Michael
Published: June 2021

Systemic and local inflammation is a common consequence of obesity, which may be associated with insulin resistance, dyslipidemia, and increased circulating inflammatory cytokines (such as TNF‐α). Therefore the goals of this study were to delineate the contributions made by inflammation and obesity to the onset of insulin resistance. To address the hypothesis that inflammation is responsible for the impairment in insulin sensitivity, we measured changes in adiposity, glucose tolerance, and plasma lipids in three groups of rats: 1) Lean strain‐control (LETO) (normal; n=5), 2) Otsuka Long‐Evans Tokushima Fatty (OLETF) (obese; n=7), and 3) OLETF + Etanercept (DOSE; n=4). Relative fat mass of Etanercept treated animals was 27% less than OLETF but still 66% higher than LETO. Glucose AUC of Etanercept treated animals was 29% lower than OLETF but still 64% higher than LETO. Plasma triglycerides in both OLETF and Etanercept treated animals were 96% higher than in LETO. Plasma TNF‐ α levels did not change in OLETF compared with LETO however TNF‐ α levels increased 34% in Etanercept treated animals compared with OLETF. These results demonstrate that obesity is made worse by inflammation and that it plays a role in the perturbation of glucose metabolism. They also suggest that other obesity associated factors contribute to impaired glucose tolerance since Etanercept treatment could not completely restore glucose tolerance to healthy levels.
Nitric oxide impacts on angiotensin AT2 receptors modulation of high‐pressure baroreflex control of renal sympathetic nerve activity in rats
Authors: Abdulla Mohammed H. , Johns Edward J.
Published: June 2021

To investigate the interaction of NO with AT2 receptor activation in the modulation of high‐pressure baroreceptor regulation of renal sympathetic nerve activity (RSNA). Experiments were carried out in chloralose/urethane anaesthetised rats and baroreflex gain curves were generated using intravenous phenylephrine and sodium nitroprusside following intracerebroventricular (I.C.V.) saline, CGP42112 (CGP), PD123319 (PD), AT2 receptor agonist and antagonist, and then in combination with L‐NAME, an NO synthase inhibitor. I.C.V. saline, PD and CGP did not change baseline mean arterial pressure (MAP), heart rate (HR) or RSNA (86±3 vs. 85±3 mmHg, 328±11 vs. 326±10 beat/min, 0.79±0.15 vs. 0.75±0.14 μV.s, respectively). The slope of the baroreflex gain curve for RSNA was increased by 64% and 107% following L‐NAME and CGP respectively but decreased by 19% following PD (all P<0.05). In the group where PD preceded L‐NAME or when PD followed L‐NAME, the slope of the baroreflex gain curve during PD plus L‐NAME infusion was reduced by about 35% (P<0.05) compared to the infusion of PD or L‐NAME alone. L‐NAME decreased the slope of the baroreflex gain curve following CGP I.C.V. administration by 33% (P<0.05). These findings suggest that NO exerts a facilitatory action allowing the normal high‐pressure baroreceptor reflex regulation of RSNA mediated through central AT2 receptor activation.

Funded by the Wellcome Trust
INCREASING LEPTIN SENSITIVITY VIA PTP1B DELETION DOES NOT INCREASE BLOOD PRESSURE THROUGH AN INCREASED SYMPATHETIC TONE IN MICE ON A BALB/C BACKGROUND
Authors: Butler Benjamin R , Norman Joseph Blake , Tremblay Michel L. , Belin de Chantemele Eric J.
Published: June 2021

Protein tyrosine phosphatase 1B (PTP1B) is a molecular brake on the leptin signaling pathway. Deletion of PTP1B increases leptin sensitivity and triggers hypertension in mice on a Balb/C background but not on a C57Bl/6 background. While leptin increases sympathetic tone (ST), whether PTP1B deletion differently increases ST in Balb/C and C57Bl/6 mice remains to be determined. To test the hypothesis that PTP1B deletion increases sympathetic tone in mice on the Balb/C background only, male and female wild‐type (WT) and knockout (KO) mice from both backgrounds were instrumented with jugular and carotid catheters to measure mean arterial pressure response to ganglionic blockade (mecamylamine) and adrenergic stimulation (phenylephrine). On the Balb/C background, PTP1B deletion increases sympathetic tone and reduces vascular adrenergic tone in both male (WT: −39±3% vs KO: −43±4%) and female mice (WT: −34±5% vs KO: − 35±4%). PTP1B deletion similarly increased ST in KO mice on the C57Bl/6 background (WT: 76±8% vs KO: 129±41%) but did not affect their adrenergic tone. Furthermore, in WT animals, sympathetic tone was higher in C57Bl/6 compared to Balb/c mice. Together these data suggest that the hypertension observed in PTP1B KO mice on the Balb/c background cannot be explained by an enhanced sympathetic tone.
Respiratory influences on muscle sympathetic nerve activity and limb vascular conductance in the steady‐state
Authors: Limberg Jacqueline K , Morgan Barbara J , Schrage William G , Dempsey Jerome A
Published: June 2021

Background

In patients with hypertension, volitional slowing of the respiratory rate has been purported to reduce arterial pressure via withdrawal of sympathetic tone.

Methods

We examined the effects of paced breathing at 7, 14, and 21 breaths per minute with reciprocal changes in tidal volume, on blood pressure, muscle sympathetic nerve activity, forearm blood flow, and forearm vascular conductance in 21 adults (8 F/13 M, 36±14 years).

Results

Alterations in breathing frequency and tidal volume did not affect steady‐state levels of blood pressure, sympathetic activity, blood flow, or vascular conductance (all p>;0.05) despite a frequency‐dependent alteration in within‐breath modulation of sympathetic outflow (i.e. increased modulation during low frequency/high volume breathing) (p=0.000). These findings were consistent across wide ranges of: 1) resting blood pressure, 2) baseline sympathetic activity, 3) cardiovascular disease risk factors.

Conclusion

Results from the current study challenge the notion that slow, deep breathing lowers arterial pressure by suppressing average sympathetic outflow and calls into question the concept that changes in sympathetic activity via volitional slowing of the respiratory rate is potentially beneficial in the treatment of hypertension. Support: AHA 10PRE3870000(JKL), NIH R01HL105820(WGS), NIH R01HL15469(JAD)
Role of forearm vasoconstriction in the development of primary raynaud's disease
Authors: Hussain Zahra , Ball Guy , Davis John E
Published: June 2021

Raynaud's Disease has been characterized as arteriolar constriction with a subsequent reduction of blood flow to the fingers. Few studies have investigated the regulation of blood flow into the hand in individuals with the disease. Therefore, the purpose of this study was to determine the relationship between Raynaud's disease and the forearm blood flow (FBF) response. Ten females (20.2±1.0 years), five control (CON) and five with the disease (RAY), completed two trials: a control visit and a cold‐induced visit. During the cold‐induced trial the left hand was placed in a cold bath (12°C) to induce Raynaud's symptoms. FBF was measured using venous occlusion plethysmography (Hokanson EC6). Reactive hyperemia was then determined by occluding the forearm for five minutes at 250 mmHg followed by peak FBF measurements. FBF and mean arterial pressure (MAP) were recorded pre, during the occlusion, and post trial. RAY exhibited the typical triphasic coloration changes indicating severe ischemia. Peak FBF after the occlusion in the cold trial was greater in RAY than CON indicating greater hyperemia (28.3 ± 4.8 vs. 26.2 ± 2.2 ml/100ml/min). MAP for CON was not different from RAY (87.37 ± 1.4 vs. 87.11 ± 2.37 mmHg). RAY demonstrated the typical ischemic response in the hand in response to a cold challenge in spite of a greater reactive hyperemia in the forearm suggesting a greater vasoconstriction response between the hand and forearm.
The inflammatory mediator SH2B3 increases risk of heart failure
Authors: Flister Michael J , Moreno Carol , Hoffman Matthew J , Prisco Sasha Z , Lazar Jozef , Hall Jennifer L , Jacob Howard J
Published: June 2021

Multiple GWAS have implicated SH2B3 with risk of myocardial infarction (MI). SH2B3 is a negative regulator of lymphopoiesis and inflammation. Despite the association of SH2B3 with increased risk of MI, the role of SH2B3 in post‐MI events that dictate survival is completely unknown. We tested the hypothesis that a damaging mutation to SH2B3 would also have a negative impact on post‐MI recovery. Sh2b3 was mutated in the SS rat (SSSh2b3). Ischemia/reperfusion injury was induced by temporary LAD occlusion for 30 min, followed by reperfusion for 7 days. Echocardiography was used to calculate the percent fractional shortening (FS). Sh2b3 expression, leukocyte infiltrate, and fibrosis were quantified by immunohistochemistry (IHC). Inflammatory gene expression was quantified by qPCR, western blot, and IHC. Compared with WT, left ventricle (LV) fibrosis of SSSh2b3 was increased (2‐fold; P<0.05) at 7 days post‐LAD, which coincided with a 10% (P<0.05) decrease in FS. At 7 days post‐ LAD, infiltration of ELA2+ neutrophils (34‐fold; P<0.001) and ED1+ macrophages (2‐fold; P<0.001) were higher in SSSh2b3 LV compared with WT. NF‐kB p65 was also upregulated in SSSh2b3 hearts (33%; P<0.001) compared with WT, as was global expression of multiple NF‐kB dependent cytokines SSSh2b3. These data provide the first evidence that SH2B3 mediates risk of post‐ MI heart failure.
Crosstalk between Toll‐like Receptor 4 and Interleukin 10 in Cardiomyocyte Survival
Authors: Bagchi Ashim K , Sharma Anita , Akolkar Gauri , Singal Pawan K
Published: June 2021

Protective role of IL‐10 may be regulated through its innate signaling via activation of Patterns Recognition Receptors such as Toll‐like receptors (TLRs). Innate responses of IL‐10 through TLRs have not been fully described. In the present study, effects of IL‐10 in the activation of TLR4 downstream signals leading to cardiomyocytes survival were examined. IL‐10 significantly activated the expression of co‐receptor CD14, TLR4 and Myeloid differentiation gene factor 88 (MyD88). Activation of TLR4 led to the translocation of the Interferon regulatory factor 3 (IRF3) into the nucleus. Phosphorylation of IRF3 enhanced mRNA synthesis for IL‐1β but not TNF‐α and was elevated even after removal of IL‐10. IRF3‐regulated NF‐κB activation and phosphorylation of p65 was also seen. Concomitantly, an increase in anti‐apoptotic Bcl‐xL activity inhibited Bax and proteolytic activity of caspase‐3 on PARP cleavage. An Inhibition of IL‐10 receptor completely attenuated the TLR4 expression suggesting that TLR4 and IL‐10 interact via receptor activation in the maintenance of cardiomyocyte homeostasis. On the other hand, when we inhibited MyD88 there was no increase in TLR4, IRF3, NF‐κB p65 and Bcl‐xL activity instead there was an increase in TNF‐α, Bax and PARP activity. Our data suggests that TLR4 and MyD88 play a crucial role in the anti‐apoptotic function of IL‐10 in cardiomyocytes.(Supported by CIHR)
Thromboxane A2 mimetic, U46619, does not induce markers of pathological hypertrophy in cardiomyocytes
Authors: Wacker Michael J , Tchikrizov Vladimir , Swan Hannah K , Wetmore Lori A , Touchberry Chad D
Published: June 2021

We have previously shown that application of the thromboxane (TxA2) receptor agonist, U46619, induces increases in intracellular calcium in isolated primary cardiomyocytes. One of the well‐known effects of sustained increases in intracellular calcium in cardiomyocytes is pathological hypertrophy. Since TxA2 is an inflammatory mediator, we hypothesized that TxA2 release during inflammation would result in cardiac hypertrophy. U46619 (0.1–10 μM) was applied to isolated primary mouse cardiomyocytes, cardiac muscle strips, and cultured HL‐1 cardiomyocytes and markers of hypertrophy were measured. U46619 treatment for 24 hrs did not increase expression of pathological hypertrophy genes (atrial natriuretic peptide, beta myosin heavy chain, skeletal muscle alpha actin) and it did not increase protein synthesis. There was also no increase in HL‐1 cardiomyocyte cell size after 48 hr treatment with U46619 as measured by flow cytometry. Previous reports have suggested that cyclooxygenase products such as TxA2 may play a role in directly inducing hypertrophy and cardiac remodeling. However, our current data would suggest that TxA2 at the doses and times we tested does not induce markers of pathological hypertrophy. (Support was provided by American Heart Association 11SDG5330016 to MJW)
The role of inflammatory responses in Alcoholic Cardiomyopathy
Authors: Walker Robin K , Haddad Georges E
Published: June 2021

Cardiovascular disease is among the major causes for increased morbidity and mortality rates. High alcohol consumption may lead to cardiomyopathy, cardiac arrhythmias, and a suite of other disorders. Previous studies in our lab have linked the AKT/PI3K pathway to cardiac hypertrophy. Alcohol consumption induces oxidative stress and increases the risk of heart disease, and several other complications involving metabolic disturbances and organ damage. Clinical features of the consequences of prolonged and excessive ethanol consumption encompass defects in myocardial contractility and derangement of cellular architecture. Oxidative stress has been reported to be the major contributor for these alcohol induced pathologies. In the present study, our aim is to investigate the effects of chronic alcohol treatments on expression of NRF2, a core regulator of antioxidant machinery on oxidative stress markers of alcohol induced cardiomyopathy. Our preliminary results in chronic alcoholic rats show that with increasing concentrations of alcohol from low (0.023% Ethanol) to High (0.461% Ethanol) we increase NRF2 and SOD‐3 gene expression. Our data suggest that NRF2 may act as a molecular switch to control the oxidative balance during chronic alcohol consumption in the heart. We will use this data to continue to examine the link between NRF2 signaling and the AKT/PI3K pathway in alcohol‐induced cardiomyopathy. This work was supported in part by grants NIH/NIAAA/1R15AAA019816–01A1, and 2G12 RR003048 RCMI/NCRR/NIH.
Molecular Mechanisms of PDGF‐D‐Induced Cardiac Fibrogenesis
Authors: Zhao Tieqiang , Zhao Wenyuan , Chen Yuanjian , Li Victoria S , Sun Yao
Published: June 2021

Our previous study showed that Platelet‐derived growth factor (PDGF)‐D and its receptors PDGFR‐β are significantly increased in fibroblasts of the infarcted heart. The role of PDGF‐D on cardiac fibrogenesis remains unknown and is explored in this study.

Methods and Results

Cardiac fibroblasts were isolated from Sprague Dawley rats and treated with PDGF‐D for 24 hr. The effect of PDGF‐D on fibroblast growth, phenotype change, collagen synthesis and degradation were investigated. Compared to controls, fibroblast proliferation increased six‐fold in cells treated with PDGF‐D. PDGF‐D stimulates fibroblast differentiation into myofibroblasts. PDGF‐D treatment significantly enhanced type I collagen secretion. Matrix metalloproteinase (MMP)‐1, MMP‐2 and MMP‐9 levels were also significantly elevated by PDGF‐D treatment, which were coincident with increased expressions of tissue inhibitor of metalloproteinase (TIMP)‐1 and TIMP‐2. Finally, PDGF‐D significantly enhanced transforming growth factor (TGF)‐β1 synthesis in fibroblasts.

Conclusions

These observations indicate that PDGF‐D promotes cardiac fibrogenesis by stimulating fibroblast proliferation, differentiation and collagen synthesis. Co‐elevations of MMPs and TIMPs counteract the effect of PDGF‐D on collagen degradation. The fibrogenic role of PDGF‐D in cardiac fibroblasts may be mediated through activating TGF‐ β1 pathway.
Antagonistic effects of mineralocorticoid receptor (MR) blockade on the vascular reactivity of male and female leptinsensitized mice
Authors: Huby Anne‐Cecile , Tremblay Michel L , Belin de Chantemele Eric J.
Published: June 2021

Leptin is an adipocyte‐derived hormone secreted in excess in obesity. Due to its ability to increase sympathetic tone, and aldosterone (Aldo) levels, leptin is viewed as a key factor involved in obesity‐related cardiovascular disease (CVD). Females secrete 4 times more leptin than males. Whether females are more sensitive to CVD than males is unknown. We hypothesize that excessive leptin levels trigger an increased Aldo secretion and exaggerated CVD in females. To test this hypothesis we analyzed the cardiovascular phenotype of mice hypersensistive to leptin due to the deletion of PTP1B, a molecular brake on leptin signaling. Irrespective of genotypes, leptin levels were 4 times higher in females. Aldo levels were increased in females and further enhanced with the deletion of PTP1B. Sex and genotype synergistically increases adrenals weight and Aldo synthase expression without effects on angiotensin II levels. Although PTP1B deficiency similarly increases blood pressure in both sexes, it only triggers an endothelial dysfunction in females that was restored by MR blockade. Vascular contractility to phenylephrine, reduced in KO males, was not affected in KO females. MR blockade restored it in males and reduced it in females. This suggests that females are more sensitive to leptin‐mediated CVD than males but also that MR antagonists have sex‐specific effects justifying the need for gender‐based therapy.
Aquatic training reduces exercise blood pressure and increases muscle eNOS
Authors: Crouse Stephen F , Greene Nicolas P , Lambert Brad S , Carradine Alex T , Joubert Dustin , Riechman Steven , Fluckey James
Published: June 2021

Exercise may reduce blood pressure (BP) and improve vasodilatory capacity thus blunting the BP response to stress. To test the efficacy of aquatic treadmill exercise (ATM) to improve BP, sedentary adults were randomized to 12‐weeks of either ATM (n = 19 ♂, 17 ♀, 41±2 yr, 173.58 ±1.58 cm, 93.19 ±3.15 kg) or land treadmill (LTM, n = 11 ♂, 13 ♀, 42 ±2 yr, 170.39 ±1.94 cm, 88.14 ±3.6 kg) training; 3sessions·wk−1, progressing to 500 kcal·session−1, 85% VO2max. A Bruce treadmill test was performed before and after training with BP measured at rest, at the end of each stage, and for 5 minutes of recovery. Twelve subjects (5 ATM, 7 LTM) volunteered for biopsies of the vastus lateralis before and after training, and muscle samples were assessed for eNOS content. Data were analyzed using Group × Time ANOVA repeated across Time, α = 0.05. Systolic BP (9–18.2mmHg), mean arterial pressure (4.8–8.3mmHg), pulse pressure (7.5–15mmHg), and rate pressure product (1.8–3.9 bpm·mm Hg·103) were reduced during exercise stress and recovery after ATM, but not after LTM training. Skeletal muscle eNOS was increased 31% in the ATM group, but not changed after LTM training. Both training modes improved VO2max (+3.6mL O2·kg−1·min−1); resting blood pressure was not altered with training. These data suggest that ATM training may increase muscle eNOS and combat hypertension.
Effects of aging and low‐load balance exercise on the expression of neurotrophins and glutamate receptors in the mouse brain
Authors: Maejima Hiroshi , Kanemura Naohiko , Kokubun Takanori , Murata Kenji , Takayanagi Kiyomi
Published: June 2021

The objective of this study was to investigate the effects of aging and low‐load balance exercise on the expression of neurotrophins and glutamate receptors in some brain regions including motor cortex, cerebellar cortex and hippocampus using senescence‐accelerated mice. The mice were assigned to four groups (adult‐control, adult‐exercise, aged‐control and aged‐exercise). The mice in the exercise groups performed balance exercise using a rotor rod (25 rpm, 15 min) three times a week for four weeks. The mRNA expression of neurotrophins, Trk receptors, and glutamate receptor subunits were measured based on real time PCR. All protocols were approved by the ethics committee for animal research of Saitama Prefectural University. Aging significantly decreased the expression of BDNF, TrkB, GluR2, NR1 and NR2B in the hippocampus. Aging also decreased the expression of BDNF, NT4 and NT3 in the cerebellar cortex. Exercise significantly increased the expression of TrkB, NR2A and NR2B only in the hippocampus of the aged mice to the expression level of the adult mice. This study elucidated the beneficial effects of the exercise on the expression of NMDA receptor and TrkB especially in the aged hippocampus, suggesting that low‐load and low‐frequency balance exercise has protective effects against degenerative disease in the aged hippocampus. This work was supported by JSPS KAKENHI Grant 21500471.
Acute oral sapropterin (Kuvan®) augments NO‐dependent reflex vasodilation in aged human skin
Authors: Stanhewicz Anna Elizabeth , Alexander Lacy M , Kenney W. Larry
Published: June 2021

Nitric oxide‐synthase (NOS) and its essential cofactor tetrahydrobiopterin (BH4) are required for full expression of reflex cutaneous vasodilation (VD). BH4 bioavailability is reduced with aging, as is VD. We hypothesized that oral sapropterin (S; BH4 sold as Kuvan®) would augment NO‐dependent VD in aged skin. Seven subjects (76±3 yrs) ingested S (10mg/kg) or placebo (P) in a randomized double‐blind crossover study design. Three microdialysis fibers were placed in the forearm skin for local delivery of Ringer's solution (control), 10mM BH4, or 20mM L‐NAME (NOS inhibitor). Three h later, red cell flux was measured over each site by laser‐Doppler flowmetry (LDF) as reflex VD was induced using a water perfused suit. At a 1°C rise in oral temperature (Tor) body temperature was clamped and L‐NAME was perfused at each site. Cutaneous vascular conductance was calculated (CVC = LDF/MAP) and normalized to maximum (sodium nitroprusside). S increased VD at the control site (S: 50±4 vs. P: 33±2%CVCmax; p<0.001). Locally adding additional BH4 increased VD in the P trial only (P: 49±5 vs. S: 49±6%CVCmax; p=0.86). At a 1°C rise in Tor S increased NOS‐dependent VD in the control site (S: 27±4 vs. P: 14±2 %CVCmax; p=0.008). Acute oral sapropterin increases NO‐dependent reflex VD in aged skin, suggesting that oral BH4 becomes bioavailable in aged skin microvasculature sufficiently to increase NO synthesis through NOS. NIH RO1‐AG07004–25
Exercise ameliorates high fat diet mediated inflammation, DNA methylation and heart failure in female mice
Authors: Chavali Vishalakshi , Harris Jessica M , Givvimani Srikant , Qipshidze Natia , Murphy Lawrence A , Tyagi Geetansh , Metreveli Naira , Tyagi Suresh C , Mishra Paras Kumar
Published: June 2021

High fat diet (HFD) causes obesity and T2D that increases the incidence of heart failure. Exercise mitigates obesity and T2D and ameliorates cardiomyopathy. However, the underlying mechanism is nebulous. We hypothesized that exercise ameliorates HFD mediated inflammation, DNA methylation and cardiac dysfunction in female mice. To test the hypothesis, twelve weeks C57BL/6J female mice were fed with normal (ND) and HFD, with and without swimming exercise for 8 weeks constituting four groups: (1) ND, (2) HFD, (3) ND and exercise (NDEx), and (4) HFD and exercise (HFDEx). The levels of anti‐inflammatory IL‐10 and DNA methyl transferase‐1, ‐3a (DNMT‐1 and ‐3a) were measured by RT‐QPCR, immunoblotting and immunohistochemistry. Cardiac dysfunction was assessed by M‐mode echocardiography. The results revealed that exercise induces IL‐10 and attenuates DNMT‐1 and ‐3a in HFD fed mice. The percentage ejection fraction (EF) and fractional shortening (FS) was decreased in HFD group but improved in HFDEx group (% EF: ND‐ 84.9±2.9, HFD‐54.9±4.3, HFDEx‐75.0±2.9, and NDEx‐93.5±1.9; % FS: ND‐ 52.9±2.6, HFD‐27.9±2.7, HFDEx‐42.5±2.9, and NDEx ‐ 65.9±3.7). These results suggest that exercise ameliorates HFD mediated cardiac dysfunction by suppressing inflammation and DNA methylation.
HIF‐1α Increases Glutamatergic NMDA receptors in the PVN during chronic heart failure
Authors: Sharma Neeru , Cunningham Craig , Liu Xuefei , Zheng Hong , Patel Kaushik
Published: June 2021

Increased sympathetic outflow is a common feature of chronic heart failure (HF). Potentiation of glutamatergic tone (increase in N‐methyl‐D‐aspartate (NMDA)‐type1 (NR1) receptors expression) within the paraventricular nucleus (PVN) has been related to the increased sympathetic drive in HF. However, the underlying molecular mechanism(s) for the upregulation of NR1 remains unclear. Immunohistochemistry of the PVN of rats with HF (coronary artery ligation‐induced) revealed upregulation of Hypoxia‐Inducible‐Factor 1α (HIF‐1α) compared to Sham. We hypothesized that increased HIF‐1α may contributes to the augmentation of the NR1 expression in the PVN of rats with HF. Initially, using an in vitro neuronal cell line (NG108–15), we found 2‐fold increase in HIF‐1α expression after 12h of hypoxia treatment in chambers. Concomitantly, hypoxia also showed significant increases in NR1 mRNA at 4h (6.5 fold) and 8h (7.2 fold) and protein levels after 12h (40%). Silencing of HIF‐1α in NG108 neurons led to decrease in expression of NR1. Taking this in vitro data to the whole animal studies, HIF‐1α knockdown in the PVN of rats with HF ameliorated the increased sympathoexcitation to NMDA (57.4±5.3 vs. 27.0±1.3). Taken together, these results suggest a contributory role for HIF‐1α in the regulation of NR1 expression, providing a novel mechanistic insight for the modulation of sympathoexcitation induced by the PVN in HF.

Supported by NIHHLS2222.
Effects of leptin in the retrotrapezoid nucleus (RTN) on CO2‐sensitivity and respiration.
Authors: Bassi Mirian , Furuya Werner Issao , Menani José Vanderlei , de Almeida Colombari Débora Simões , do Carmo Jussara Márcia , da Silva Alexandre , Hall John Edward , Wenker Ian C , Mulkey Daniel , Colombari Eduardo
Published: June 2021

Evidence suggests that, in addition to regulate energy homeostasis, leptin also contributes to the CNS control of breathing in response to changes in CO2/H+ (i.e., central chemoreception). However, cellular targets of leptin‐dependent drive to breathe have not been elucidated. Here, we tested the effects of leptin on hypercapnic ventilatory response in leptin deficient mice (ob/ob: 42±2 g) in vivo, and on CO2‐responsiveness of RTN neurons and astrocytes in brain slices isolated from rat pups (P7–12). We found that 3‐ day unilateral RTN injections of leptin (1 μg/100 nl, n=7/group) increased ventilatory responsiveness to 7% CO2 in ob/ob mice (4378±294 μl.min−1.g−1, vs. 2849±319 μl.min−1.g−1in vehicle group). Immunohistochemical analysis using antibodies for leptin receptors, astrocytes (aldehyde dehydrogenase 1L1) and neurons (biocytin) suggest that leptin receptors are expressed by RTN astrocytes but not neurons in ob/ob mice. We also found that acute in vitro exposure to leptin in RTN slices (10 min, 50 nM) elicited no effect on excitability of chemosensitive neurons (cell‐attached current clamp) or conductance of CO2‐sensitive astrocytes (whole‐cell voltage clamp; Ihold −80 mV). These results suggest that although long‐term application of leptin into the RTN increased respiratory drive in ob/ob mice, the cellular and molecular mechanisms remain unclear.
Key role for the multimodal CaSR in pulmonary neuroepithelial body microenvironment physiology
Authors: Lembrechts Robrecht , Brouns Inge , Schnorbusch Kathy , Pintelon Isabel , Kemp Paul J , Timmermans Jean‐Pierre , Riccardi Daniella , Adriaensen Dirk
Published: June 2021

The neuroepithelial body (NEB) microenvironment consists of densely innervated groups of neuroendocrine cells, representing complex sensory receptors in the airways, and a stem cell population. The extracellular Ca2+‐sensing receptor (CaSR) is a master regulator of extracellular free ionized Ca2+ ([Ca2+]o), and a multimodal sensor able to integrate inputs from a variety of physiological stimuli. Immunostaining and (q)RT‐PCR recently revealed a selective CaSR expression on the plasmamembrane of NEB cells in postnatal mouse lungs. We further aimed at exploring potential roles for the CaSR in pulmonary NEB physiology. Ca2+ imaging of mouse lung slices demonstrated a CaSR‐mediated rise in intracellular Ca2+ concentration ([Ca2+]i) following an increase of [Ca2+]o or application of established CaSR agonists. The CaSR was shown to be involved in regulating baseline [Ca2+]i in NEBs, and in mediating intercellular communication in the NEB microenvironment. By integrating multiple physio(patho)logical signals and coordinating intra‐ and extracellular Ca2+ signaling, the CaSR appears to serve key roles for the NEB microenvironment as a complex chemosensory receptor and airway stem cell niche.
Cascade transmission in skeletal muscle arteries
Authors: Kluess Heidi A
Published: June 2021

Cascade transmission is the release of ATP from smooth muscle secondary to activation of the α1‐adrenergic receptor and occurs in the skeletal muscle vasculature, but the functional significance is currently unknown. Femoral arteries from Fisher 344 female rats (2–3 months old) were prepared for wire myography. Phenylephrine (10−5M) was added and developed tension was recorded for 14 minutes (n=5). Following washing, either the P2 antagonists, PPADS or suramin or both were added 20 minutes prior to phenylephrine. In a subset of artery rings, phenylephrine was added a second time without blockers to ensure that phenylephrine‐mediated tension was not declining compared to the baseline phenylephrine. The hypothesis was that if cascade transmission contributed to α1‐mediated vasoconstriction, then blocking P2 receptors would result in attenuation of developed tension. Tension was attenuated with PPADS (14±11%), suramin (23±10%) and both PPADS and suramin (32±16%)(p<0.05; all were different from phenylephrine only and double block attenuated more than PPADs). To assess whether this affect was specific to α1‐mediated vasoconstriction, potassium chloride (60mM; n=3) was substituted for phenylephrine. PPADS and suramin did not attenuate potassium chloride‐mediated vasoconstriction. These data suggest that a portion of α1‐mediated vasoconstriction is caused by cascade transmission.
Pde3a‐deficient mice have evidence of pulmonary hypertension
Authors: Chen Bernadette , Meng Xiaomei , Jin Yi , Nelin Leif D
Published: June 2021

Pulmonary hypertension (PH) is associated with vasoconstriction and vascular remodeling characterized by pulmonary artery smooth muscle cell (PASMC) proliferation. In vitro, human PASMC proliferation requires arginase II (arg II) and cAMP elevating agents prevent hypoxia‐induced arg II induction. We hypothesized that Pde3a‐deficient mice have attenuated PH. Pde3a−/− (KO) and wild type (WT) mice were exposed to 21%O2 (normoxia) or 10%O2 (hypoxia) for 28d. Right ventricle systolic pressure (RVSP) was measured. 2D echocardiography was used to measure pulmonary acceleration time/ejection time (PAT/PET). The mice were sacrificed; lungs and hearts were harvested. RV and left ventricle (LV)+septum (S) were weighed and ratio of RV/(LV+S) weights calculated. Lung arg II and cAMP levels were measured. KO mice had higher RVSP, lower PAT/PET ratios, and higher RV/(LV+S) ratios compared to WT mice. KO mice had greater lung cAMP, but arg II protein levels did not differ from WT mice. Interestingly, KO mice exposed to hypoxia had similar RVSP, PAT/PET and RV/(LV+S) ratios as hypoxia‐exposed WT mice. Pde3a‐deficient mice have evidence of PH as seen by RVSP, PAT/PET and RV/(LV+S) ratios. Interestingly, hypoxia exposure did not result in any worsening of PH in KO mice. Our data suggest that alterations in Pde3a gene function may underlie forms of PH not associated with hypoxia, such as primary pulmonary arterial hypertension.
Postnatal‐related changes in cAMP mediated pulmonary arterial relaxation and calcium signals persist following long term hypoxia in sheep
Authors: Paez Ricardo , Rubalcava Monica , Blood Quintin , Hong Sam , Francis Michael , Taylor Mark S , Longo Lawrence D , Wilson Sean M
Published: June 2021

Phosphodiesterase (PDE) inhibition can elevate cAMP, dilate pulmonary arteries (PA) and is a therapeutic target for persistent pulmonary hypertension of the newborn. To test whether long term hypoxia (LTH) impairs postnatal maturation of cAMP‐mediated vasodilation and associated Ca2+ signals we reduced cAMP degradation by treating PAs with a non‐selective PDE inhibitor (IBMX). Wire‐myography and confocal Ca2+ imaging were performed on PA isolated from fetal, newborn, or adult sheep that lived at low (720 m) or high altitude (3,801 m) for >;100 days. IBMX caused a dose‐dependent relaxation of serotonin‐constricted PA from all groups and reduced Ca2+ wave amplitude as well as other spatial and temporal components to the Ca2+ signals in newborns but not in fetuses. In arteries from adult normoxic sheep, IBMX impaired spatial and temporal Ca2+ signals. Yet, IBMX also reduced Ca2+ wave amplitude in arteries of LTH adults. LTH increased Ca2+ wave amplitudes in newborns and modified spatial and temporal components to the waves, but failed to alter signals in the fetus. With regards to development, Ca2+ wave amplitudes were elevated in the newborn relative to the fetus and the adult, while spatial and temporal aspects were unchanged. These results suggest that cAMP dilates immature and adult pulmonary arteries, in part, by depressing Ca2+ signals. NSF MRI923559, NIH R03HD69746, R01HD31226, R01HD3807, P20MD6988
Hydrogen peroxide induced changes in endothelial function
Authors: Patel Hemang , Chen Juan , Daoud Sarah , Kavdia Mahendra
Published: June 2021

Pathophysiology of various vascular disorders is characterized with disproportionate changes in cellular redox equilibrium resulting in oxidative stress. Increased oxidative stress is assessed for its effects on cellular function changes. One of the key hypotheses is the increase in oxidative stress and related increase in hydrogen peroxide. In this study, we investigated the effect of continuous and bolus H2O2 treatments on endothelial cells. Following both H2O2 treatments, we measured gene expression levels of key ROS neutralizing enzymes such as SOD, catalase (CAT), glutathione peroxidase 1 (GPX1) and peroxiredoxin 1 (PRDX1), and cell signaling proteins such as ASK1, ATF2 and Nrf2. We also measured O2− production and mitochondrial membrane polarization using fluorescence probes DHE and JC10 respectively. Results showed a significant increase in O2− production which remained higher under constant H2O2 treatment compared to bolus treatment. Gene expression results indicated a significant down‐regulation in ASK1, CAT, TXNRD1 under continuous H2O2 exposure. Bolus H2O2 exposure followed by remodeling period showed significant up‐regulation in GPX1 and TXNRD1 whereas genes expression of ASK1, SOD1 and PRDX1 returned to homeostasis. The results are significant to further understanding of H2O2 induced changes on endothelial cell function during oxidative stress. Supported by NIH R01 HL084337.
Effect of prenatal antioxidant sulforaphane on fetal transcriptomics in mice
Authors: Cho Hye‐Youn , Miller‐DeGraff Laura , Perrow Ligon , Yamamoto Masayuki , Kleeberger Steven R
Published: June 2021

Nrf2 is essential in antioxidant defense. Health benefits of dietary Nrf2 agonists have been demonstrated. However, little is known about gestational antioxidant in organogenesis. To determine the effect of a prenatal Nrf2 agonist on embryonic lung and placenta transcriptomics, time‐pregnant Nrf2+/+ and Nrf2−/− mice were supplemented with sulforaphane (SUL) or vehicle at embryonic (E) days 11–17. Uteri were removed at E18.5, and embryonic lung and placenta were dissected for cDNA microarray analysis. Gestational SUL regulated lung genes such as antioxidants (Akr1c19, Gstt1), albumin, histocompatibility, and cathepsins in Nrf2+/+ embryos, which were associated with cell cycle and cancer, immune cell trafficking, and metabolisms. Pulmonary SUL effects were relatively marginal in Nrf2−/− embryo tissues. Nrf2‐ dependently modulated lung genes by SUL including adam‐like, decysin 1, Nrf2 heterodimer partners (Bach1, Maff), and mitochondrial ribosomal proteins were involved in RNA process, protein ubiquitination, and cellular maintenance. In placenta, Nrf2‐ dependent SUL responsive genes (Cd4, Ptger2) were associated with organogenesis. In conclusion, prenatal antioxidant causes in utero signaling that profoundly regulates embryonic and extraembryonic tissue transcriptomics. Results have insights into maternal diet and fetal programming. Supported by the NIEHS Intramural Program.
Dependence of cytotoxicity of menadione and cytoprotection by antioxidants in human endothelial cells on oxygen levels: Atmospheric oxygen versus physiological levels
Authors: Rastogi Ashish , Stavchansky Salomon , Bowman Phillip
Published: June 2021

The goal of in vitro screens of potential cytoprotective agents is to identify drugs that will be beneficial in vivo. However, in vitro screens are usually performed on cells cultured in atmospheric oxygen (AtmO2; 20.9%), which is much higher than the levels found in tissues in vivo (3–5%). The aim of this study was to evaluate the cytotoxicity and cytoprotective effects of an oxidant generating injurant (50, 60, and 70μM menadione; MD) and several antioxidants on human umbilical vein endothelial cells (HUVEC). Dose response studies demonstrated that 50μM MD reduced viability by 85% at AtmO2, but only by 20% at 3%O2. Antioxidants (N‐acetyl cysteine, gamma‐glutamyl cysteine, and glutathione) were more effective cytoprotectants at 3%O2 than AtmO2, and lower doses (5 and 50μM) were more effective at 3% O2 than AtmO2. However, all three compounds proved to be cytoprotective to HUVEC against MD‐induced oxidant stress at their highest dose of 500μM. These preliminary results indicate that the relatively high amount of oxygen in room air is a substrate for generating oxidants, and screens for cytoprotective antioxidants might be more predictive of in vivo performance if done at more physiologic levels.
Reduced transepithelial glucose movement in metformin‐treated airways correlates with inhibition of hyperglycemia‐induced bacterial growth
Authors: Garnett James P , Baker Emma H , Tregoning John S , Baines Deborah L
Published: June 2021

Raised blood glucose elevates airway glucose and promotes respiratory infection. We investigated the effect of metformin on airway Staphylococcus aureus growth.

Inoculation of H441 monolayers with 5×105 CFU/cm2S. aureus (8325–4) for 7h reduced transepithelial electrical resistance and enhanced paracellular glucose flux (assessed using 14C‐L‐glucose; P<0.05 and P<0.0001 respectively, n=8). 1 mM metformin attenuated these changes (P<0.001). Apical S. aureus growth increased with basolateral glucose concentration (10–40 mM). Growth was impaired by metformin pre‐treatment (P<0.05, n=9). Metformin had no effect on H441 monolayer 14C‐D‐glucose uptake or S. aureus growth in microbial culture.

6–10 week old db/db mice (leptin receptor deficient; blood glucose 17.7±1.6 mM, n=10) intranasally inoculated with 107 CFU S. aureus had 382±57% more CFU in their bronchoalveolar lavage after 24h (P<0.001, n=10), compared to WT mice (C57BL/6; blood glucose 7.4±0.1 mM, n=10). Treatment with 40 mg/kg metformin for two days prior to infection reduced S. aureus CFU in db/db mice by 50±9% (P<0.01, n=10) compared to PBS‐treated db/db mice, without reducing blood glucose levels. Metformin reduced paracellular glucose flux across ex vivo mouse tracheas by 40±5% (P<0.05, n=3).

These data indicate that metformin inhibits hyperglycaemia‐induced S. aureus growth by reducing paracellular diffusion of glucose into the airways.
TNF‐a–mediated hyperglycemia in Obese Zucker rats following orthopedic trauma
Authors: Xiang Lusha , Mittwede Peter N , Clemmer John S , Lu Silu , Hester Robert L
Published: June 2021

Obese patients with orthopedic trauma exhibit increased inflammation and complications correlated with high glucose levels. We hypothesize that in obesity there is increase risk of trauma‐induced hyperglycemia due to insulin resistance and inflammation. Fasted lean (LZ) and obese Zucker (OZ) rats were treated with vehicle or etanercept, a TNF‐α inhibitor (2mg/kg, ip.). One hour after the treatment, orthopedic trauma was mimicked by soft tissue injury followed by an injection of bone components into bilateral hindlimbs. Glucose levels were measured for 6 hours following trauma. Under control conditions, OZ exhibited similar basal fasting glucose levels but impaired glucose tolerance (OGTT) as compared with LZ. Etanercept treatment had no effect on the OGTT in LZ or OZ. After trauma, the glucose levels in LZ were moderately increased within 10 minutes and decreased to basal levels after 6 hours (Figure). However, OZ exhibited a severe hyperglycemia as compared with LZ during the 6 hours of recovery after trauma. Etanercept treatment markedly improved the trauma‐induced hyperglycemia in OZ with no effect in LZ. These results suggest an exacerbated trauma‐induced hyperglycemia in obesity due to TNF‐α‐dependent mechanisms. Supported by AHA‐12SDG12050525, NIH HL‐51971, and HL‐89581
Identifying novel plasma biomarkers of pancreatic beta‐cell function using acute and chronic models of hyperglycemia.
Authors: Solomon Thomas P.J. , Karstoft Kristian , Knudsen Sine H , Pedersen Bente K
Published: June 2021

Beta‐cell function is impaired in type 2 diabetes. Identifying related plasma metabolites related to insulin secretion may help identify novel treatment targets. Intravenous glucose‐stimulated insulin secretion (GSIS) was measured in healthy subjects before and after acute 24‐hour experimental‐elevation of plasma glucose (+5 mM). GSIS was also measured in age/BMI‐matched type 2 diabetic (T2D) patients. The plasma metabolite profile (358 compounds) was determined using LC/GC‐MS and correlated with group differences in GSIS and with hyperglycemia‐induced changes in GSIS. GSIS was lower in T2D compared to controls (6.8±0.8 vs. 10.1±0.9 pmol/kg/min; P<0.05), but elevated following experimental hyperglycemia in healthy controls (13.1±0.8). Hexadecanedioate, octadecanedioate and 3‐aminoisobutyrate were significantly correlated with GSIS (r= −0.66,−0.61,−0.56; P<0.05) showing the same direction of change in both acute and chronic models of hyperglycemia. These plasma metabolites are biomarkers of beta‐cell function in humans and may reveal novel therapeutic targets. The effect of these compounds on GSIS in perifused pancreatic islets is currently being determined.
Markers of acute cardiovascular inflammation induced by angiotensin II in a murine model
Authors: Santana Andre Bento Chaves , Souza‐Oliveira Thais , Barauna Valério , Souza Leandro , Irigoyen Maria Claudia , Campos Luciene , Krieger José Eduardo , Lacchini Silvia
Published: June 2021

Angiotensin II has important physiological functions for the homeostasis of the cardiovascular system and may also induce to inflammatory responses. The aim of this study was to evaluate the effetc of subpressor angiotensin II (AngII) on expression of inflammatory markers in cardiac vessels.

Were used C57Bl/6J male mice, treated with subpressor dose of AngII (30ng/kg IP), confirmed by carotid catheterization and arterial pressure measure after 10, 30, 60min, and 2 and 6hours of AngII injection (n=5/saline; n=5/AngII). Inflammatory markers were evaluated in cardiac vessels (TGF‐beta, IL‐6 and iNOS) by western blot, and localized in vessels by immunohistochemistry. Mice were evaluated after 1 and 24 hours to identify acute responses. Results were compared by ANOVA, using p≤0.05 as significant.

Blood pressure measurements showed no changes in arterial pressure and heart rate. Protein analysis showed an increase of inflammatory markers in cardiac tissue after 1 hour TGF‐beta (84%), IL‐6 (90%) and iNOS (70%). However, these markers were unchanged after 24 hours. Immunohistochemistry analysis showed a specific increase in these markers associated to cardiac vessels.

The results suggests that, independently on hemodynamic influences, Angiotensin II leads to expression of inflammatory markers in cardiac vessels in a short period, and this may represent a direct pro‐inflammatory action mediated by angiotensin II.