bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infarct Size Reduction by Remote Ischemic Perconditioning in Pigs Requires Activation of the SAFE but not the RISK Pathway
Authors: Kleinbongard Petra , Gent Sabine , Skyschally Andreas , Heusch Gerd 
Published: November 2023

Brief episodes of ischemia/reperfusion in a tissue or organ remote from the heart can reduce myocardial infarct size following sustained severe ischemia/reperfusion. Such remote conditioning can be induced before (pre‐) or during (per‐) myocardial ischemia, and protection by remote conditioning was confirmed in all species tested so far, including humans. In pigs, cardioprotection by remote preconditioning causally involves the activation of the survival activating factor enhancement (SAFE) pathway, whereas the activation of the reperfusion injury salvage kinase (RISK) pathway is not necessary (Circ Res 2015;117:279–88). We have now used a clinically relevant pig model to identify the myocardial signal transduction of remote ischemic perconditioning (RPERC).Anesthetized open‐chest pigs were subjected to 60 minutes occlusion of the left anterior descending coronary artery (LAD), followed by 180 minutes reperfusion. RPERC (n=10) was induced by 4×5/5 minutes hindlimb ischemia/reperfusion during the last 40 minutes of ischemia. Placebo pigs (PLA; n=10) without hindlimb ischemia/reperfusion served as controls. Regional myocardial blood flow was measured with colored microspheres. The area at risk (AAR) was delineated by atrial injection of 5 ml blue dye after LAD re‐ligation at the end of the experiment. Infarcted tissue was demarcated by TTC staining and calculated as % of the AAR. Myocardial biopsies were taken before LAD occlusion (baseline) and at 10 min reperfusion from the AAR to determine changes in the phosphorylation of protein kinase B and extracellular signal‐regulated kinase 1/2 as the main RISK pathway components and the phosphorylation of signal transducer and activator of transcription 3 as the central SAFE pathway component by Western blot. In additional experiments, RPERC was performed in the presence of either RISK‐blockade (Wortmannin/U0126; n=4) or SAFE‐blockade (AG490; n=4).Residual myocardial blood flow during ischemia and AAR were not different between groups. RPERC reduced infarct size to 16±10% vs. 42±10% in PLA (mean±SD; p<0.05; t‐test). RPERC increased the phosphorylation of STAT3 at 10 min reperfusion (p<0.05), whereas PLA did not. The SAFE‐blockade abolished both, the increased phosphorylation of STAT3 and the protection by RPERC (infarct size 36±5%; n.s. vs. PLA). In both groups phosphorylation of RISK was increased from baseline to 10 minutes reperfusion. RISK‐blockade abolished this increase, but RPERC still protected the myocardium (infarct size 8±1%; p<0.05 vs. PLA).The present experiments confirm the causal involvement of STAT3 activation during cardioprotection by RPERC in pigs, whereas an activation of RISK components is not involved. Thus, cardioprotection by RPERC is characterized by the same signal transduction pattern as that of remote ischemic preconditioning and local ischemic postconditioning.
The Cardioprotective Effects of Caffeic Acid Phenethyl Ester (CAPE) on Myocardial Ischemia/Reperfusion (I/R) Injury
Authors: Castellano Andrew J. , Kuhn Tarah , Liu Stephanie , Kucharski Kevin , Venditto Joseph , Kuo Daniel , Barsotti Robert , Young Lindon H. , Chen Qian 
Published: November 2023

Oxidative stress plays a major role in causing reperfusion injury following prolonged ischemia. CAPE has been shown to have antioxidant, anti‐inflammatory, and cardioprotective effects following regional myocardial ischemia/reperfusion injury. The effects and mechanisms of CAPE in global myocardial I/R injury are still unclear. In this study, CAPE was tested in isolated perfused rat hearts following global I (30 min)/R (60 min). We recorded left ventricular developed pressure (LVDP), left ventricular end systolic pressure (LVESP), the peak of the first derivative of left ventricular pressure (dP/dtmax), and infarct size. We found that untreated I/R hearts (n=11) recovered LVDP to 45 ± 8% (p<0.05), LVESP to 106 ± 7% (p<0.05), and dP/dtmax to 33 ± 5% (p<0.05) of baseline values, respectively, at the end of 60 minutes reperfusion. By contrast, CAPE (40 μM, n=6) given at reperfusion for 5 minutes significantly restored LVDP to 75 ± 15%, LVESP to 133 ± 13%, and dP/dtmax to 54 ± 12% of baseline values, respectively (all p<0.05). Moreover, CAPE also significantly reduced infarct size to 19 ± 2% (n=6) compared to 30 ± 6% in untreated I/R hearts (n=11, p<0.05). Additionally, a non‐selective nitric oxide synthase inhibitor, NG‐nitro‐L‐arginine methyl ester (L‐NAME, 50 μM, n=5), or a heme oxygenase‐1 inhibitor, SnPP (20 μM, n=5), significantly abolished all the cardioprotective effects of CAPE (all p<0.05). These results suggest that CAPE, when given at reperfusion, improves post‐reperfused contractile function and reduces infarct size. The cardioprotective effects may be mediated by increasing nitric oxide bioavailability and/or heme oxygenase activity.Support or Funding InformationThis study was supported by Division of Research and Department of Bio‐Medical Sciences at Philadelphia College of Osteopathic Medicine.
Cardiovascular Susceptibility to Acute Myocardial Ischemic Injury in Male And Female Rat Offspring Born Growth Restricted
Authors: Shah Amin , Matsumura Nobutoshi , Morton Jude Sandra , Dyck Jason , Davidge Sandra Thomas 
Published: November 2023

BackgroundIschemic heart disease causes the greatest mortality in the world today. Epidemiological and animal studies have shown that populations who suffer intrauterine growth restriction (IUGR), one of the most common consequences of complicated pregnancies, are more susceptible to develop cardiovascular disorders in later life. We tested the hypothesis that adult male and female IUGR rat offspring are more susceptible to develop cardiac dysfunction following acute myocardial ischemic injury.MethodsMale and female control or IUGR rat offspring (created by exposing pregnant dams to hypoxia, 11.0±0.5% O2, for the last third of pregnancy) were randomly assigned to undergo sham or myocardial infarction (MI) surgery (by ligation of the left anterior descending coronary artery) at the age of 12 weeks. Thus the experimental groups consisted of: Control‐sham, Control‐MI, IUGR‐sham, and IUGR‐MI. One week after MI surgery, echocardiography was performed to assess cardiac morphometry, systolic function and diastolic function.ResultsFemale, but not male, IUGR offspring had lower body weight compared to controls at 12 weeks of age post 1 week of MI. Anterior left ventricular (LV) wall thickness was decreased whereas LV internal diameter during diastole was significantly increased in both control‐MI and IUGR‐MI groups independent of sex or IUGR; indicating wall thinning and LV dilatation due to MI. Ejection fraction, fractional shortening and fractional area change were significantly decreased in both control‐MI and IUGR‐MI groups in male and female offspring. The Tei index was significantly increased in both control‐MI and IUGR‐MI male groups. Interestingly, E/E’ ratio, an index of ventricular filling pressure, was significantly increased in only male IUGR‐MI group compared to IUGR‐Sham (IUGR‐Sham vs IUGR‐MI: 19.84 ± 2.13 vs 35.21 ± 3.66, P<0.05) and control‐MI (Control‐MI vs IUGR‐MI: 22.37 ± 1.73 vs 35.21 ± 3.66, P<0.01).ConclusionIschemic heart disease such as MI was shown to alter LV wall morphometry leading to LV dilatation in both sexes. MI impaired systolic function independent of being born growth‐restricted or sex. However, male IUGR offspring were more susceptible to develop diastolic dysfunction following acute MI. These studies indicate a susceptibility of the male IUGR population to develop diastolic heart failure due to acute myocardial ischemia.Support or Funding InformationThis work is funded by grants from the Canadian Institutes of Health Research (CIHR); and the Women and Children's Health Research Institute (WCHRI) through the generous contributions of the Stollery Children's Hospital Foundation (SCHF) and the Royal Alexandra Hospital Foundation (RAHF). A shah is supported by fellowships from the Heart and Stroke Foundation of Canada.
Membrane Potential Controls Surface Expression of BK Channel Auxiliary β1 Subunits in Arterial Smooth Muscle Cells
Authors: Leo M. Dennis , Bulley Simon , Kuruvilla Korah P. , Jaggar Jonathan H 
Published: November 2023

Intravascular pressure stimulates arterial depolarization, leading to smooth muscle cell (myocyte) voltage‐dependent calcium (Ca2+) channel activation and vasoconstriction. Membrane depolarization also activates BK channels, which oppose pressure‐induced depolarization and constriction, but mechanisms involved are unclear. We have previously shown that nitric oxide stimulates rapid surface expression of β1 subunits in arterial myocytes. These β1 subunits activate surface‐resident BK channels, leading to vasodilation. Here, we tested the novel hypothesis that membrane potential controls β1 trafficking to regulate BK channel activity. Using techniques, including surface biotinylation, immuno‐FRET microscopy, western blotting and gene knockdown, we show that membrane depolarization (30–60 mM K+ PSS) rapidly (<10 min) increased the surface abundance of BK channel auxiliary β1 subunits in cerebral artery myocytes. Depolarization‐induced β1 trafficking was inhibited by: 1) brefeldin A, a trafficking inhibitor, 2) knockdown of rab11A, a small GTPase associated with recycling endosomes, 3) rab11A dominant negative mutant overexpression, 4) nimodipine, a CaV1.2 channel blocker, 5) HA‐1100, a rho kinase (ROCK) inhibitor, but not by KN93, a Ca2+/calmodulin‐dependent protein kinase inhibitor, or LY294002, a specific PI3 kinase inhibitor, 6) ROCK2, but not ROCK1, knockdown. HA‐1100 also reduced GTP‐bound active rab11 in arteries. These data indicate that membrane depolarization stimulates surface trafficking of β1 through a mechanism that involves voltage‐dependent Ca2+ channel and ROCK2 activation in arterial myocytes.Support or Funding InformationRO1 HL67661, HL110347, HL094378 to JHJ and American Heart Assoc.‐SDG to MDL
Leptin, Melanocortin 4 receptor and Renal Nerves Play a Role in High Blood Pressure Programmed by Intrauterine Growth Restriction in Mouse
Authors: Intapad Suttira 
Published: November 2023

Intrauterine growth restriction (IUGR) is a risk factor for hypertension and cardiovascular disease in later life. However, the underlying mechanisms remain unclear. We previously showed that male mouse IUGR offspring exhibit high blood pressure and adiposity compared to control offspring. Increased circulating adipocyte‐derived leptin activates the brain melanocortin system, in particular the melanocortin 4 receptor (MC4R); these key factors increase renal sympathetic nerve activity and result in elevated blood pressure. Nonetheless, the effects of the leptin‐MC4R‐renal nerve pathway on blood pressure (BP) in IUGR is unknown. In the present studies, we tested the hypothesis that the leptin‐MC4R‐renal nerve pathway plays a role on the high BP observed in male IUGR mice. To determine the contribution of leptin and renal nerve activity to hypertension in male IUGR offspring, Pregnant C57BL/6J female mice underwent sham or reduced uterine perfusion (RUP) surgery at day 13 of gestation; pregnancy was allowed to come to full term. Offspring from RUP dams were IUGR; progeny from sham surgeries were used as controls. IUGR offspring had lower birth weights than controls (P<0.01). Mean arterial pressure (MAP) was measured via carotid catheter in conscious adult (24 weeks old) male control and IUGR mice with or without bilateral renal denervation (RDV) for 2 weeks. IUGR offspring had a higher BP compared to controls (125.0±3.7 vs 112.1±2.1 mmHg; n=7, P<0.05). RDV did not alter MAP of control mice (110.7±1.8 mmHg; n=3) but significantly decreased MAP of IUGRs (115.0±2.0 mmHg; n=4). Serum leptin levels were significantly (P<0.05) increased in IUGR (28.1±1.9 ng/ml; n=5) compared to controls (12.6±3.1 ng/ml; n=5). We also assessed the role of MC4R on BP of IUGR mice. Male and female MC4R+/−breeders were used to generate MC4R+/+ and MC4R−/− littermates to avoid the undesirable effects of obesity in MC4R−/− dams. RUP induction in pregnant MC4R+/−dams and MAP measurements of their offspring were conducted as aforementioned. IUGR MC4R+/+ mice had a significantly higher (P<0.05) MAP (135.0±4.0 mmHg; n=4) than control MC4R+/+ animals (120.0±5.3 mmHg; n=4). MAP of control MC4R +/− (n=6) and MC4R −/− (n=3) were not significantly different from control MC4R+/+. MAP of IUGR MC4R +/−(125.0±7.0 mmHg; n=5) was slightly lower but not significantly different from IUGR MC4R+/+. However, IUGR MC4R−/− showed a significant decrease (P<0.05) in MAP (117.0±6.7 mmHg; n=3) compared to IUGR MC4R+/+. Together our data suggests that leptin, renal nerves, and MC4R are involved in IUGR programs an increase blood pressure in mice. Thus, the leptin‐MC4R‐renal nerve pathway is a putative mechanism underlying the hypertension of IUGR offspring.Support or Funding InformationThis work was supported by COBRE pilot grant GM104357 from National Institutes of Health
Gene Variants in Sodium Bicarbonate Cotransporter NBCe2 Increase Sodium and Bicarbonate Transport in Human Renal Proximal Tubule
Authors: Gildea John , Carlson Julia M , Tran Hanh T , Xu Peng , Kemp Brandon A , Langouët‐Astrié Christophe J , Carey Robert M , Jose Pedro A , Felder Robin A 
Published: November 2023

RationaleThe sodium bicarbonate cotransporter NBCe2 (encoded by SLC4A5) is involved in the regulation of renal tubular sodium bicarbonate transport. We hypothesized that human SLC4A5 single nucleotide polymorphisms (SNPs, rs10177833 and rs7571842) increase NBCe2 expression and renal proximal tubule (RPT) sodium transport and may be a cause of salt sensitivity of blood pressure.ObjectiveTo characterize the function of wild‐type (WT) and homozygous variants (HV) of SLC4A5.Methods and ResultsThe expressions of NBCe2 mRNA and protein were not different between RPT cells (RPTCs) carrying WT (n=4) or HV SLC4A5 (n=6) before or after dopaminergic or angiotensin (II and III) stimulation. However, total transcellular (luminal to basolateral) RPTC sodium transport, NHE3 protein expression, and Cl−/HCO3− exchanger activity were higher in HV than WT SLC4A5. Bicarbonate‐dependent pH recovery after an intracellular acid load, as well as NBCe2 mRNA and protein, was increased when intracellular sodium was elevated (5.2±1.1 mM) in HV SLC4A5 compared with WT SLC4A5 (pH recovery Vmax 0.22±0.02 and Km 6.39±0.81 in HV vs Vmax 0.28±0.02 and Km 4.30±0.53 in WT, P<0.05, P<0.05, n=3). The increased NBCe2‐specific bicarbonate‐dependent pH recovery in HV was verified in stable SLC4A5 shRNA cell lines (n=8/12/group). RPTCs carrying HV SLC4A5 had increased binding of HNF4A to SLC4A5 DNA (1.52±0.10‐fold, N=3, P<0.05, t‐test), using purified HNF4A and ChIP and oligo binding assays. Additionally, the difference between HV and WT in bicarbonate‐dependent pH recovery was abolished by two HNF4A antagonists. RPTCs isolated from human urine of salt‐sensitive subjects who are HV for SLC4A5 had increased bicarbonate dependent pH recovery, relative to salt‐resistant subjects who are WT for SLC4A5 (n=4/group).ConclusionsNBCe2 activity is stimulated by an increase in intracellular sodium and is hyper‐responsive in RPTCs carrying HV SLC4A5 through an aberrant HNF4A‐mediated mechanism, which may be a key mechanism in the etiology of human salt sensitivity.
Compound 21 Prevents Salt Induced Myocardial Hypertrophy
Authors: Dopona Ellen Priscila Brito , Favoni Veronica , de Oliveira Ivone Braga , Heimann Joel Claudio 
Published: November 2023

ObjectiveTo evaluate the role of Compound 21 (C21) in a model of salt overload on left (LV) and right (RV) ventricular hypertrophy and fibrosis.MethodsMale Wistar rats were fed normal‐ (NS ‐ NaCl = 1,27%, n=8) or high‐ (HS ‐ NaCl = 8%; n=8) salt diet from weaning up to 18 weeks of age. From the 7th week of age, one HS subgroup received Compound 21 (1mg/kg per day by gavage, n=8). Body weight (BW), tail‐cuff blood pressure (BP), cardiac mass to tibia length ratio (CM/TL), cardiomyocyte transverse diameter (TD), percentage of cardiac fibrosis (FI) were measured.ResultsAt 7th week of age, BW was higher in HS+C21 and NS than in HS. BW in HS+C21 did not differ from NS from the 7th week to the 18th week of age. BP in HS+C21 was higher than in NS and lower than in HS from the 7th week to the 18th week of age.ConclusionIn Wistars rats, compound 21 prevents left and right ventricular hypertrophy and left ventricular fibrosis.Support or Funding InformationThis study was supported by FAPESP (2013/08418‐4)

Results: (mean ± standard error of the mean ‐ p<0.05):

Variable
Weeks
NS
HS
HS+C21

Body Weigh (g)
3
65±1.5
65±2.4
64±3.5

18
560±19.4
493±16.4*
566±15.5

BP(mmHg)
6
112±3.0
114±4.2
111±3.4

18
116±2.5
144±1.2*
135±1.8*#

HEART

Total
0.44±0.04
0.47±0.04
0.45±0.06

CM/TL (g/m)
18
RV
0.07±0.007
0.07±0.01
0.07±0.01

LV
0.26±0.02
0.29±0.02
0.29±0.04

TD(μm)
18
RV
9.82±0.21
13.80±0.29*
9.79±0.21

LV
10.17±0.2
15.60±0.9*
10.41±0.09

FI (% área)
18
RV
0.87±0.23
0.92±0.13
0.60±0.05

LV
0.25±0.05
0.82±0.08*
0.33±0.03#

p<0.05 vs. NS;
p<0.05 vs. HS
High Salt Activates Human Monocytes and Promotes their Conversion into Dendritic Cells via Formation of Immunogenic Isoketal‐adducts
Authors: Kirabo Annet , Barbaro Natalia , Foss Jason David , Montaniel Kim Ramil , Chen Wei , Harrison David Glenn 
Published: November 2023

High blood pressure is a major modifiable risk factor for cardiovascular disease (CVD) which is the leading cause of death worldwide. Excessive salt intake and inflammation are implicated in the genesis of hypertension. It has recently become evident that sodium accumulates in the interstitial space and can promote inflammation through poorly defined mechanisms. We recently published a new pathway in which increased oxidative stress in dendritic cells (DCs) leads to formation of isoketal‐modified proteins which act as neo‐antigens to activate T cells. We hypothesized that increasing sodium chloride (NaCl) in excess of the physiological interstitial space concentrations activates antigen presenting cells via formation of immunogenic isoketals. We exposed monocytes from human volunteers to normal physiological NaCl (150 mM/L), elevated NaCl concentrations (190 mM/L), or an equiosmoloar concentration of mannitol. We found that exposure of human monocytes to high salt, but not mannitol, caused a 2‐fold increase in formation of isoketal‐modified proteins. This was associated with an increase in activation marker CD86 (466 ± 192 normal salt vs 596 ± 324 high salt) and production of inflammatory cytokines IL‐6, IL‐β and TNF‐α. Interestingly, these cells expressed surface markers indicative of transformation to DCs, as evidenced by their acquisition of surface marker CD83. In additional immunofluorescence studies, we found that monocytes exposed to high salt for 7 days acquire a DC like morphology. Moreover, using flow cytometry, we confirmed that high salt exposure causes these cells to lose the monocyte marker CD14, and gain the DC marker CD209. When co‐cultured with T cells from the same patients, these cells drive T cell proliferation. Scavenging of isoketals during high salt exposure prevented conversion of monocytes into DCs and their ability to drive T cell proliferation. Thus, we have defined a novel pathway whereby high NaCl concentrations lead to transformation of monocytes to DCs due to increased formation of immunogenic isoketals. These observations provide insight into how elevated sodium environments lead to an inflammatory state.Support or Funding InformationThis work is supported by National Institutes of Health grants R01HL039006, P01HL058000, P01HL095070, P01GM015431, R01HL108701, R01HL105294, VITA award HHSN268201400010C and the Strategically Focused Research Network Award from the American Heart Association.
High salt intake alters renal medullary clock genes via ETB receptors
Authors: Speed Joshua S , Hyndman Kelly A , Kasztan Malgorzata , Johnston Jermaine G , Roth Kaehler J , Young Martin E , Pollock Jennifer S , Pollock David M 
Published: November 2023

Diurnal rhythms in various physiological functions are driven by the oscillations of several transcription factors including Bmal1, period (Per), cryptochrome (Cry), and clock, collectively termed the molecular clock. The renal inner medullary collecting duct (IMCD) is an important site for Na+ handling and contains several clock factors. The IMCD also produces ET‐1 in response to high salt intake and contains a high density of endothelin B (ETB) receptors that promote the excretion of Na+. Disruption of renal ETB receptors reduces the ability of kidney to excrete a salt load in rodents, especially when salt is given prior to the inactive period vs. the active period. These data suggest an interaction between renal ETB receptors and the molecular clock to promote the excretion of excess Na+. Given that knockout of the circadian clock gene Bmal1 reduces blood pressure during the active period in mice, we hypothesized that a high salt intake suppresses the clock mechanism in the renal inner medulla via ETB receptor activation. Transgenic control (Tg con) or ETB deficient (ETB def) rats were fed normal (NS, 0.49% NaCl) or high (HS, 4% NaCl) salt for two weeks. Rats were euthanized every 4 hours beginning at zeitgeber time 0 (lights on) for tissue collection and subsequent assessment of circadian clock genes. Renal inner medullary Bmal1 oscillation was phase shifted in Tg con rats in response to HS compared to NS fed rats. On the other hand, Bmal1 expression was similar between NS and HS fed ETB def rats indicating that the phase shift in Tg con rats is ET‐dependent. In addition, renal inner medullary Per1 expression was similar between all groups; however expression of Per2, Cry1, and Cry2 were suppressed during normal acrophase in response to HS in both Tg con and ETB def rats suggesting that this is ET‐independent. Further, in cultured mouse IMCD cells, treatment with ET‐1 significantly reduced Bmal1 mRNA. Finally, knockdown of Bmal1 with siRNA significantly reduced mRNA expression of the epithelial Na+ channel alpha subunit (ENaCα) (1.0±0.06 vs. 0.74±0.07, control vs. Bmal siRNA: p<0.05) and increased transepithelial resistance (583.0±43.3 vs. 703.5±32.6 ohms, control vs. Bmal siRNA: p=0.056) in mouse IMCD cells. These data suggest that activation of renal inner medullary ETB receptors during high salt intake functions to regulate the normal circadian pattern of Bmal1 expression in order to suppress ENaCα and promote the excretion of excess Na+.Support or Funding InformationThis work is supported by NIH P01 HL95499 and P01 HL69999 to DMP and American Heart Association grant 15SDG25090194 to JSS.