bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardioplegic Strategies for Calcium Control
Authors: Fukuhiro Yoshiaki , Wowk Michelle , Ou Ruchong , Rosenfeldt Franklin , Pepe Salvatore 
Published: July 2021

Background—Ca2+overload plays an important role in the pathogenesis of cardioplegic ischemia-reperfusion injury. The standard technique to control Ca2+overload has been to reduce Ca2+in the cardioplegic solution (CP). Recent reports suggest that Na+/H+exchange inhibitors can also prevent Ca2+overload. We compared 4 crystalloid CPs that might minimize Ca2+overload in comparison with standard Mg2+-containing CP: (1) low Ca2+CP (0.25 mmol/L), (2) citrate CP/normal Mg2+(1 mmol/L Mg2+), (3) citrate CP/high Mg2+(9 mmol/L Mg2+), and (4) the addition of the Na+/H+exchange inhibitor HOE-642 (Cariporide). We also tested the effect of citrate titration in vitro on the level of free Ca2+and Mg2+in CPs.Methods and Results—Isolated working rat heart preparations were perfused with oxygenated Krebs-Henseleit buffer and subjected to 60 minutes of 37°C arrest and reperfusion with CPs with different Ca2+concentrations. Cardiac performance, including aortic flow (AF), was measured before and after ischemia. Myocardial high-energy phosphates were measured after reperfusion. The in vitro addition of citrate to CP (2%, 21 mmol/L) produced parallel reductions in Mg2+and Ca2+. Because only Ca2+was required to be low, the further addition of Mg2+increased free Mg2+, but the highest level achieved was 9 mmol/L. Citrate CP significantly impaired postischemic function (AF 58.3±2.5% without citrate versus 41.6±3% for citrate with normal Mg2+,P<0.05, versus 22.4±6.2% for citrate with high Mg2+,P<0.05). Low-Ca2+CP (0.25 mmol/L Ca2+) significantly improved the recovery of postischemic function in comparison with standard CP (1.0 mmol/L Ca2+) (AF 47.6±1.7% versus 58.3±2.5%,P<0.05). The addition of HOE-642 (1 μmol/L) to CP significantly improved postischemia function (47.6±1.7% without HOE-642 versus 62.4±1.7% with HOE-642,P<0.05). Postischemia cardiac high-energy phosphate levels were unaffected by Ca2+manipulation.Conclusions—(1) A lowered Ca2+concentration in CP is beneficial in Mg2+-containing cardioplegia. (2) The use of citrate to chelate Ca2+is detrimental in the crystalloid-perfused isolated working rat heart, especially with high Mg2+. (3) The mechanism of citrate action is complex, and its use limits precise simultaneous control of Ca2+and Mg2+. (4) HOE-642 in CP is as efficacious in preservation of the ischemic myocardium as is the direct reduction in Ca2+.
Abstract 182: Dosing Time of Angiotensin Converting Enzyme Inhibitor is Important for Protecting Organ Damage in Hypertension
Authors: Tsujino Takeshi , Matsumoto Mika , Naito Yoshiro , Chikako Yoshida , Wakabayashi Kana , Sakoda Tsuyoshi , Ohyanagi Mitsumasa , Masuyama Tohru 
Published: July 2021

Introduction: There is a difference in the pattern of the diurnal variations of the aortic and cardiac mRNA expression of renin-angiotensin system between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats. Angiotensin II-dependent upregulation of gene expression was enhanced only in the daytime in the aorta of SHR.
Hypothesis: Dosing time of angiotensin converting enzyme inhibitor may influence its organ protective effect in genetic hypertension.
Methods: 10-week-old stroke prone spontaneously hypertensive rats (SHR-SP) were kept in a room in which a 12-h light/12-h dark cycle was maintained [lights on at 7 a.m.; Zeitgeber time (ZT) 0]. They were divided into three groups:

the control group(C group: n=28)was given vehicle

the morning group (M group: n=23) was given captopril (30mg/kg) at ZT0

the evening group (E group: n=23) was given captopril (30mg/kg) at ZT12.

After 1 week of treatment, ACE activities of heart and kidney were measured 6 hours after drug-administration (n=8 for each group). After 7 weeks of treatment, urinary protein excretion, creatinine clearance, and heart weight/body weight ratio (HW/BW, mg/g) were examined. Five rats for each group underwent long-term implantation of a device that telemetrically monitors blood pressure (BP).
Results: Mean BP elevation and premature death were equally prevented in the M group and E group compared to the C group. BP was lower in the day and higher in the night in the M group (day time BP vs. night time BP: 145.9 ± 10.3 vs. 163.7 ± 19.2 mmHg, p<0.01), while BP was stable throughout a day in the E group (day time BP vs. night time BP: 152.2 ± 14.2 vs. 153.5 ± 14.7 mmHg, n.s.). After 1 week of treatment, cardiac and renal ACE activities were lower in the M group than in the E group (cardiac ACE activities: 0.639 ± 0.130 vs. 0.842 ± 0.085 nmol/mg tissue/hr, p<0.01; renal ACE activities: 0.402 ± 0.145 vs. 0.728 ± 0.165 nmol/mg tissue/hr, p<0.001). After 7 weeks of treatment, creatinine clearance was higher and HW/BW was lower in the M group than in the E group (2.93± 0.57 vs. 2.01± 0.43, p<0.005; 4.33± 0.19 vs. 4.63 ± 0.36 g/kg, p<0.05).
Conclusions: Morning administration of captopril was more effective than evening one in terms of the strength of ACE inhibition and organ protection in SHR-SP.
Abstract 805: Differential Regulation Of Cytokine-induced Alternative Splicing Of The TF Gene By Serine/Arginine Rich Protein Kinases
Authors: Rauch Ursula , Eisenreich Andreas , Poller Wolfgang , Schultheiss Heinz-Peter 
Published: July 2021

Background: Higher eukaryotes control gene expression and increase protein diversity by alternative splicing of pre-mRNA. The Cdc2-like kinase (Clk) family, DNA topoisomerase I (DNA topo I) or Akt kinase are involved in splicing control by regulating the phosphorylation state of serine/arginine rich (SR) proteins. We recently showed that alternatively spliced human tissue factor (asHTF), a soluble isoform of tissue factor (TF), the primary initiator of coagulation, is expressed in HUVECs in response to inflammatory cytokines. This study investigated the role of Clks, DNA topo I and the PI3K-Pathway in regulation of TF-splicing in TNF-α induced HUVECs.
Methods: HUVECs were incubated with inhibitors of Clks, DNA-topo I or PI3K and were then stimulated with TNF-α. The SR protein phosphorylation state was determined 2 min post induction. The full length (fl) TF and asHTF mRNA were assessed 60 min post induction by Real-Time PCR. Proteins were measured 5 and 8 hours after stimulation by Western blots and the cell thrombogenicity was analyzed via a chromogenic assay.
Results: TNF-α inceased the mRNA expression of asHTF and flTF in HUVECs. The Clk-inhibitor completely inhibited the TNF-α induced expression of asHTF and reduced flTF by 30 %. Inhibition of DNA topo I increased asHTF expression and reduced the flTF expression. Inhibition of the PI3K/Akt-pathway had no effect on TF mRNA expression. Reduced Clk-inhibition the TF activity by 50 % whereas DNA topo I inhibition significantly decreased the procoagulant TF activity 8 hours post TNF-α induction. The Clk- and DNA-topo I-inhibitors altered the SR-protein phosphorylation pattern post TNF-α-induction. Additionally resulted inhibition of Clks in the generation of a third TF mRNA-splice variant, TF-A.
Conclusion: Selective inhibition of Clks or DNA topo I leads to alterations of SR-protein phosphorylation and affects the differential expression of TF isoforms, thereby modulating the thrombogenicity of HUVECs. The inhibition of Clks contributes to the generation of a third TF splice variant. The inhibition of these kinases gives new insights into the regulation of the TF gene splicing process, which may result in new therapeutic strategies for modulating cellular thrombogenicity.
Abstract 806: Protein Disulfide Isomerase (PDI) signals Tissue Factor (TF)-dependent Fibrin formation in vivo
Authors: von Bruehl Marie-Luise , Grahl Lenka , Konrad Ildiko , Lorenz Michael , Schulz Christian , Reinhardt Christoph , Manukyan Davit , Altmann Berid , Dlugai Silke , Mackman Nigel , Engelmann Bernd , Massberg Steffen 
Published: July 2021

Background: Pathological fibrin formation is a predominant cause for arterial thrombosis, triggering myocardial infarction and stroke. Tissue factor (TF), which is expressed by vascular endothelium and cell-derived microparticles, is a central trigger of intravascular fibrin generation. In intact blood vessels, TF is only minimally active, and the coagulation system is down-regulated. In contrast, TF is rapidly stimulated following endothelial disruption. However, the molecular mechanisms that trigger fibrin formation via regulation of TF activation are largely undefined.
Methods and Results: Here, we have identified a novel pathway that leads to TF activation in vitro and contributes to intravascular coagulation in vivo. We show that the protein disulfide isomerase (PDI) induces disulfide formation of the Cys186/Cys209 pair located in the extracellular domain of TF. In vitro, PDI-mediated disulfide formation led to profound activation of TF. In vivo, we found that PDI is not present in the intact vessel wall, but becomes abundantly expressed following vessel damage. We show that injured smooth muscle cells and adherent/activated platelets are the major cellular sources of PDI at sites of vascular injury. We then assessed fibrin formation following injury of the common carotid artery using intravital microscopy. We observed that PDI-blockade strongly reduced fibrin formation by approximately 45– 60%. Likewise, intravenous infusion of PDI significantly enhanced TF-dependent fibrin formation. Together, this implies that PDI initiates coagulation in vitro and also during arterial thrombosis in vivo. Notably, PDI did not act on platelets to trigger intravascular coagulation. Correspondingly, PDI blockade also inhibited fibrin formation, when platelet adhesion was prevented using a function-blocking anti-GPVI antibody.
Conclusion: These findings reveal for the first time in vivo that the thiol isomerase PDI is a major molecular trigger of blood coagulation, which is exposed after vessel injury and converts TF into its functionally active form. Hence, PDI represents a promising novel target for the treatment of pathologic fibrin formation in patients with thrombotic disorders.
Abstract 811: Long-term Patency of a Small-diameter Vascular Graft Made of Fibroin, a Silk-based Biodegradable Material
Authors: Enomoto Soichiro , Sata Masataka , Sumi Makoto , Asakura Tetsuo , Nagai Ryozo 
Published: July 2021

Background: There is an increasing need for vascular grafts in the field of surgical revascularization. However, smaller vascular grafts made from synthetic biomaterials, particularly smaller than 5 mm in diameter, are associated with high incidence of thrombosis. Fibroin is a biodegradable protein derived from silk. Fibroin provides anti-thrombotic surface and serves as a scaffold for various cell types in tissue-engineering. In this study, we evaluate the potential of fibroin to generate artificial vascular prosthesis for small arteries.
Methods and Results: A small artificial vessel with three layers was woven from fibroin thread. Fibroin-based grafts (1.5 mm in diameter, 10 mm in length) were implanted into the abdominal aorta of male 10 to 14-week-old Sprague Dawley rats by end-to-end anastomosis. Polytetrafluoroethylene (PTFE)-based grafts were used as control. Patency of fibroin grafts at 1 year after implantation was significantly higher than that of PTFE grafts (85.1% vs. 30%, p<0.01). Endothelial cells and smooth muscle cells migrated into the fibroin graft early after implantation and organized endothelial and medial layers, as determined by anti-CD31 or anti-α-smooth muscle actin immunostaining. Vasa vasorum was also formed in adventitia. Sirius-red staining revealed that the content of collagen in fibroin grafts significantly increased at 3 months after implantation (1613.5 ± 246.3%, p<0.01) with decrease in fibroin fiber content (70.6 ± 4.6%, p<0.05). To investigate the origin of the cells of neointima and media, we performed bone marrow transplantation from GFP rats to wild-type rats. GFP-positive cells substantially contributed to organization of endothelium and smooth muscle layers in the fibroin grafts that had been implanted into the bone marrow chimeric rats.
Conclusion: A small-diameter fibroin-based vascular graft has significantly higher patency than a PTFE-based graft. Bone marrow-derived cells contribute to vascular remodeling after graft implantation. Fibroin might be a promising material to engineer vascular prosthesis for small arteries.
Abstract 860: Phenotypic Characterization Of Murine And Human Cardiac-resident Progenitor Cells Isolated On Basis Of Aldehyde-dehydrogenase Activity
Authors: Spicher Albert , Meinhardt Andrea , Roehrich Marc-Estienne , Vassalli Giuseppe 
Published: July 2021

Identification of stem cells based on hematopoietic stem cell (HSC) surface markers, such as stem cell antigen-1 (Sca-1) and the c-kit receptor, has limited specificity. High aldehyde-dehydrogenase (ALDH) activity is a general cellular property of stem cells shared by HSC, neural, and intestinal stem cells. The presence of cells with high ALDH activity in the adult heart has not been investigated.
Methods: Cells were isolated from adult mouse hearts, and from atrial appendage samples from humans with ischemic or valvular heart disease. Myocyte-depleted mouse Sca-1+, and lineage (Lin)-negative/c-kit+ human heart cells were purified with immunomagnetic beads. ALDH-high cells were identified using a specific fluorescent substrate, and sorted by FACS. Cell surface marker analysis was performed by flow cytometry.
Results: Myocyte-depleted mouse heart cells contained 4.8+/−3.2% ALDH-high/SSC-low and 32.6+/−1.6% Sca-1+ cells. ALDH-high cells were Lin-negative, Sca-1+ CD34+ CD105+ CD106+, contained small CD44+ (27%) and CD45+ (15%) subpopulations, and were essentially negative for c-kit (2%), CD29, CD31, CD133 and Flk-1. After several passages in culture, ~20% of ALDH-high cells remained ALDH-high. Myocyte-depleted human atrial cells contained variable numbers of ALDH-high cells ranging from 0.5% to 11%, and 4% Lin-negative/c-kit+ cells. ALDH-high cells were CD29+ CD105+, contained a small c-kit+ subpopulation (5%), and were negative for CD31, CD45 and CD133. After 5 passages in culture, the majority of ALDH-high cells remained ALDH-high.
Conclusions: Adult mouse and human hearts contain significant numbers of cells with high ALDH activity, a general cellular property that stem cells possess in different organs, and express stem cell markers (Sca-1 and CD34 in the mouse). The immunophenotype of cardiac-resident ALDH-high cells differs from that previously described for bone marrow ALDH-high HSC, and suggests that this cell population may be enriched in mesenchymal progenitors. Analysis of lineage differentiation potential of ALDH-high cells is in progress. ALDH activity provides a new, practical approach to purifying cardiac-resident progenitor cells.
Abstract 1137: Switch From Nitric Oxide To Hydrogen Peroxide Mediated Dilation In Coronary Arterioles Of Obese Rats
Authors: Focardi Marta , Ziche Marina , Marzilli Mario 
Published: July 2021

Background. Obesity is associated with coronary endothelial dysfunction, an early marker of atherosclerosis; but impaired endothelial function in obese Zucker rats appears not to be mediated by NO production.
Hypothesis: We tested the hypothesis that endothelial derived hyperpolarizing factor (EDHF) is responsible for endothelial dilation in obese rats.

Methods: We used 4 groups of male Zucker rats: lean and obese on normal and low carb diets. Rats were fed
ad libitum
for 3 weeks; caloric intake and weight gain were similar. Coronary arterioles were cannulated and pressurized for diameter measurements. Vasodilation to acetylcholine (Ach) and flow was determined before and after incubation with L-NAME (10 μm), an inhibitor of NO synthase, plus the cyclooxygenase inhibitor indomethacin (Indo; 10 μm), after tetraethylammonium (TEA 1 mM), a non-selective K
+
channel antagonist, and after catalase, a H
2
O
2
scavenger (CAT; 500 U/ml).

Results Acetylcholine-induced vasodilation was impaired in obese rats compared to lean (41%; n=5
vs
87%; n=3; p<0.05) and did not change after L-NAME+Indo incubation in obese both on normal (47 ± 19%; n = 4
vs
. 40 ± 13%; n = 4;
p
=ns) and low carb diet (51 ± 1%; n = 3
vs
. 59 ± 6%; n = 3;
p
=ns). Flow-induced dilation was impaired in obese rats compared to lean (38%;n=5
vs
78%; n=2;p<0.05) and this dilation was not affected by L-NAME+Indo incubation in obese both on normal (45±12%; n=4
vs
48±10% n=4;
p
=ns) and low carb diet (53±14%; n=3
vs
61±12% n=3;
p
=ns). Importantly, TEA incubation decreased Ach dilation both in obese on normal (41±11%; n=5
vs
13±7% n=5;
p<
0.05) and low carb diet (76±25%; n=3
vs
22±18% n=3;
p<
0.05). Similar results were obtained during flow-induced dilation in obese both on normal (37±17%; n=5
vs
14±7% n=5;
p<
0.05) and low carb diet (54±14%; n=3
vs
15±3% n=3;
p<
0.05). Catalase administration blocked both FID and Ach dilation in obese both on normal (FID 45±15%
vs
5±3% n=3;
p<
0.05; Ach 39±14%
vs
12±5% n=3; p<0.05) and low carb diet (FID 52±19%
vs
18±7% n=2;
p<
0.05; Ach 75±35%
vs
15±2% n=2;
p<
0.05).

Conclusions: Endothelial dependent vasodilation of coronary arterioles in obese Zucker rats is mediated by H
2
O
2
and increases in endothelial function in obese rats on a low carb diet is mediated by increased H
2
O
2
-induced dilation.
Abstract 1295: The Vasomotor Effects of Apelin in vivo in Man
Authors: Japp Alan G , Cruden Nicholas L , Amer David A , Goudie Ewan B , Johnston Neil R , Webb David J , Megson Ian L , Flapan Andrew D , Newby David E 
Published: July 2021

BACKGROUND In preclinical models, apelin, the endogenous ligand for the G protein-coupled APJ receptor, lowers systemic venous tone, causes nitric oxide (NO)-mediated arterial vasodilatation and is the most potent inotrope yet studied. We aimed to establish the in vivo vasomotor effects of apelin in man.
METHODS Dorsal hand vein diameter was measured by the Aellig technique in 6 subjects during local intravenous infusions (0.1–3 nmol/min) of two apelin agonists, apelin-36 and (Pyr1)apelin-13, and sodium nitroprusside (SNP; 0.6 nmol/min) in the presence and absence of norepinephrine preconstriction. Forearm blood flow (FBF) responses to intrabrachial infusions of apelin-36 and (Pyr1)apelin-13 (0.1–30 nmol/min) were measured by venous occlusion plethysmography in 8 subjects on 4 occasions. In a 2×2 factorial design, a further 8 subjects received an intrabrachial infusion of (Pyr1)apelin-13 (0.3–3 nmol/min) in the presence or absence of the NO clamp (NO synthase inhibitor, L-N-monomethylarginine (8 micromol/min), co-infused with SNP (1–128 ng/min) to maintain basal flow and clamp endogenous NO production), and following a single oral dose of aspirin (600 mg) or matched placebo.
RESULTS Although SNP caused venodilatation (P<0.0001), apelin-36 and (Pyr1)apelin-13 had no effect on dorsal hand vein diameter in the presence or absence of norepinephrine (P=0.2). Both apelin-36 and (Pyr1)apelin-13 caused reproducible dose-dependent vasodilatation in forearm resistance vessels (P<0.0001): maximal increase of 198+/−27% and 90+/−7% respectively. Vasodilatation had a rapid onset (within 6 min) and slow offset that remained 36 min post-infusion (P<0.01). Plasma apelin concentrations and non-infused FBF (P<0.05) were increased at doses >3 nmol/min, consistent with systemic spillover. (Pyr1)apelin-13-mediated vasodilatation was attenuated by the NO clamp (AUC reduced by 64%; P=0.004) but was unaffected by aspirin (P=0.7).
CONCLUSION Although having no apparent effect on venous tone, apelin causes a rapid onset and sustained NO-dependent arterial vasodilatation in vivo in man. The apelin-APJ system merits further clinical investigation to determine its role in cardiovascular homeostasis and its therapeutic potential in heart failure.
Abstract 1395: Role of High Mobility Group Box 1 Protein in Post-Infarction Healing Process and Left Ventricular Remodeling
Authors: Kohno Takashi , Anzai Toshihisa , Yoshikawa Tsutomu , Naito Kotaro , Ueno Koji , Miyasho Taku , Okamoto Minoru , Yamada Shingo , Ishizaka Akitoshi , Ogawa Satoshi 
Published: July 2021

Background: The appropriate infarct healing process is prerequisite for preventing left ventricular (LV) remodeling after myocardial infarction (MI). High mobility group box1 protein (HMGB1) is derived from necrotic cells and activated macrophages and involved in tissue repair as immunostimulatory signal. However, the role of HMGB1 in post-MI LV remodeling is unknown.
Methods and Results: We examined 35 patients with first ST-elevated acute MI. Peak serum HMGB1 level, determined by serial measurements (q. 6h), did not differ in age, sex, coronary risk factors and infarct site. Its peak level was markedly higher in patients with adverse in-hospital clinical outcomes, including pump failure, cardiac rupture, LV aneurysm and cardiac death, compared with those without (all p<0.05). Then we performed experimental study using rat MI model, induced by permanent left coronary ligation. Anti-HMGB1 antibodies (1 mg/day, MI/antiH, n=20) or control antibodies (MI/C, n=20) were injected subcutaneously every 24 hours for 7 days. Sham-operated rats served as controls (n=10). Quantitative RT-PCR and immunoblotting showed that HMGB1 expression was increased in the infarcted area peaking at day 3 in MI/C compared with sham (p<0.05). Its expression was localized in myocytes and inflammatory cells by immunohistochemistry. The mRNA level of TNF-α (−48%, p=0.03) and IL1-β (−44%, p=0.02) and the number of infiltrated macrophages (p=0.04) in the infarcted area were markedly reduced at day 3 in MI/antiH compared with MI/C. Echocardiographic and hemodynamic studies at day 7 showed increased LV end-diastolic dimension (p=0.03), LVEDP (p=0.03), and decreased LV max dP/dt (p=0.01) in MI/antiH compared with MI/C. Histologically, scar thinning in the infarcted area (0.53±0.23 vs 0.68±0.21 mm, p=0.02) and hypertrophy in the non-infarcted myocardium (2.01±0.23 vs 1.63±0.21 mm, p=0.03) were more prominent in MI/antiH compared with MI/C at day 14.
Conclusions: Elevation of serum HMGB1 level is associated with adverse clinical outcomes in patients with acute MI. However, blockade of HMGB1 in rat MI model aggravated early LV remodeling through impaired infarct healing and advanced scar thinning, suggesting an essential role of HMGB1 in the appropriate repairing process after MI.