bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebral autoregulation, individual variability, and white matter hyperintensity (1069.1)
Authors: Liu Jie , Tseng Benjamin , Khan Muhammad , Tarumi Takashi , Hill Candace , Armstrong Kyle , Mirshams Niki , Hodics Timea , Zhang Rong
Published: June 2021

Purpose: To assess regional cerebral autoregulation (CA) and its association with white matter hyperintensities (WMH) in older adults.

Methods: Twenty‐seven healthy older subjects (13 females, 68 ± 6 yr) underwent fluid‐attenuated inversion recovery MRI to measure WMH. Cerebral blood flow (CBF) in the internal carotid (ICA) and vertebral arteries (VA) was measured using color‐coded duplex ultrasonography. CA was assessed during steady‐state changes in mean arterial pressure (MAP) from ‐11 ± 7% to 21 ± 8% (relative to baseline) and quantified by a linear regression slope between percentage changes in cerebrovascular resistance (CVR=MAP/CBF) and MAP. Multiple linear regression analysis was used to explore the relationship between regional CA and WMH.

Results: Substantial individual CA variability was found in both ICA and VA with the regression slopes of CVR to MAP ranged from 0.366 to 2.198 in the ICA and from 0.172 to 3.175 in the VA. CA measured in the VA had a positive correlation (r = 0.741, P < 0.001) with periventricular WMH (PWMH), after adjustment for age, central arterial stiffness, sex and resting blood pressure. Of note, individuals with more PWMH (> 0.3 % intracranial volume) showed a hyper‐reactivity of CA (i.e., a paradoxical reduction in CBF during increases in arterial pressure) at the VA. Interpretation: Large individual CA variability exists in healthy older adults. The association between the hyper‐reactivity of posterior CA and PWMH suggests that the presence of small cerebral vessel disease may lead to hypoperfusion in the posterior cerebral circulation during acute increase in blood pressure.

Grant Funding Source: NIH grant R01AG033106‐01 and R01HL102457.
A2A adenosine receptor‐mediated increase in coronary flow is dependent on NADPH oxidase‐derived reactive oxygen species (1071.1)
Authors: Labazi Hicham , Rajamani Uthra , Tilley Stephen L , Ledent Catherine , Mustafa S. Jamal
Published: June 2021

Adenosine induces an increase in coronary flow (CF) mainly through the activation of both A2A and A2B adenosine receptors (ARs); however, the mechanisms responsible for the regulation of CF are not fully understood. Earlier data from our laboratory showed an interaction between adenosine, NADPH oxidase (NOX) and reactive oxygen species (ROS). We hypothesize that adenosine‐mediated increase in CF is dependent upon NOX activation through A2A but not A2B AR. Concentration response curves to adenosine and the A2A AR selective agonist (CGS‐21680) were performed in isolated perfused hearts from WT, A2A and A2B AR knockouts (A2AKO and A2BKO). Adenosine‐induced dose‐dependent increase in CF was significantly decreased (p<0.05) with pre‐treatment with gp91 ds‐tat (a NOX inhibitor; gp91) or EUK134 (a catalase/superoxide dismutase mimic ; EUK) in both WT (WT: 229.7% ± 6.5 vs. WT+gp91: 178% ± 5.9 and WT: 228.4% ± 7.2 vs. WT+EUK: 178.8% ± 5.5) and A2BKO ( A2BKO: 241.3% ± 9.1 vs. A2BKO+gp91: 191% ± 8.7 and A2BKO: 254% ± 9.3 vs. A2BKO+EUK: 194.4% ± 7.9), but not in A2AKO isolated hearts (P>0.05) (A2AKO: 271.5% ± 17.4 vs. A2AKO+gp91: 240.8% ± 13.6 and A2AKO: 271.2% ± 18.4 vs. A2AKO+EUK: 257.6% ± 15.6). Also, CGS‐21680 caused a concentration‐dependent increase in CF in both WT and A2BKO, but not in A2AKO, which was significantly reduced (P<0.05) using gp91 (WT: 226% ± 8.4 vs. WT+gp91: 191.6% ± 6.6 and A2BKO: 182.6% ± 4.4 vs. A2BKO+gp91: 159.7% ± 4.3). Our data suggest that adenosine‐induced increase in CF through the activation of A2AKO AR is dependent upon NOX activation and ROS generation.

Grant Funding Source: Supported by HL 094447, HL 027339 and AI 096139
Attenuated insulin induced dilation in coronary arteries from obesity resistant and obesity prone high fat fed rats (1071.6)
Authors: Oltman Christine , Dake Brian
Published: June 2021

The purpose of this study was to compare physiologic, metabolic and microvascular complications in obesity resistant (OR) and obesity prone (OP) rats fed a high fat (HF) diet. 8 week old male rats were fed a diet containing 45% kcal saturated fat for 42 weeks. Blood pressure was measured by telemetry. Reactivity of small (75 ‐ 150 μm intraluminal diameter) coronary arteries was evaluated. Body weights were 504±7, 669±25*, 685±8*, and 924±39* grams for OR chow, OR HF, OP chow OP HF rats, respectively. Blood pressure was increased in OP rats on control diet (121.5 ± 4.3mmHg*) and further increased with HF diet (129.7 ± 2.4mmHg*), compared to OR rats on control (98.3 ± 4.3mmHg) or HF diet (99.5 ± 3.1mmHg). Glucose clearance was impaired in high fat fed OR and OP rats. Insulin mediated relaxation of coronary arteries from HF fed OR and OP rats was impaired (% relaxation to 100 ng/ml: OR chow = 37.1 ± 15, OR HF = 4.6 ± 5.3, OP chow = 29.3 ± 6.6 and OP HF = 7.6 ± 2.3). Acetylcholine (ACh)‐mediated relaxation of coronary arteries from HF fed rats was impaired (%relaxation to 10 μM Ach: OR chow=67 ± 10, OR HF = 36±12*, OP chow = 41±8*, and OP HF = 22±6*). Sodium nitroprusside (SNP) responses were not altered. *p<0.05 vs OR chow diet. These studies indicate that HF diet augments metabolic and microvascular complications in obesity prone rats.

Grant Funding Source: Supported by VA Merit to Dr. Oltman
Temporal response of monocytes during progressive coronary artery occlusion (1071.7)
Authors: Hakimzadeh Nazanin , van Horssen Pepijn , van Lier Monique , van den Wijngaard Jeroen , Belterman Charly , Coronel Ruben , Piek Jan , Spaan Jos , Verberne Hein , Siebes Maria
Published: June 2021

Elevated levels of circulating monocytes (MCs) have been correlated with collateral development in coronary artery disease patients. The aim of this study was to employ a model of progressive coronary artery occlusion (CO), in order to compare the temporal response of MC upregulation in the systemic circulation vs. their infiltration into ischemic myocardium.

An ameroid constrictor was implanted on the left coronary artery of New Zealand White rabbits (CO after 7‐10 days). Peripheral blood MCs were isolated, fluorescently labelled and administered intravenously, 9 (n=4),16 (n=4) or 28 (n=5) days after surgery. Coronary vessels were perfused with fluorescent cast. Hearts were processed with an imaging cryomicrotome, generating 3D reconstructions of the vascular network and MCs.

Peripheral blood MCs increased 83.47±55.18% 9 days after CO surgery, while 16 and 28 days after CO surgery showed 39.96±65.27 and ‐13.82±24.17 % change, respectively. MC subset ratios (classical/non‐classical) showed the largest percentage increase after 16 days CO in peripheral blood. In the myocardium, MC infiltration was localized in the ischemic area, and was highest after 16 days vs. 9 days CO (0.027±0.023 vs. 0.017±0.001 of total heart volume, p<0.05). Collateral connections coincided with MC localization. In conclusion, we note that the temporal MC response in the systemic circulation may differ from that in the myocardium.

Grant Funding Source: Supported by the Center for Translational Molecular Medicine (EMINENCE).
Coronary vascular function is improved in ischemic patients after continuous‐flow left ventricular assist device implantation (1071.8)
Authors: Deeter Lance , Diakos Nikos , Stehlik Josef , Selzman Craig , Kfoury Abdallah , Reid Bruce , Saidi Abdulfatah , Wever‐Pinzon Omar , Verma Divya , Yen Chi‐Gang , Uzoigwe Emmanuella , Guo Shawn , Li Dean , Drakos Stavros , Symons J David
Published: June 2021

Continuous‐flow left ventricular assist devices (LVADs) are used in heart failure (HF) patients either as a bridge to transplantation or as a permanent (destination) therapy. HF is precipitated by myocardial infarction (MI) in most (ischemic; I) but not all (non‐ischemic; NI) patients. We hypothesized that coronary vascular dysfunction is greater in I (63±2 y; n=12) vs. NI (53±5 y; n=17) male HF patients, and that dysfunction is reversed by LVAD support. Arteries from a transmural biopsy of the left‐ventricle were obtained, and concentration‐response curves to bradykinin (BK, 10‐6 to 10‐10 M) and sodium nitroprusside (SNP, 10‐4 to 10‐9 M) were completed after vessels were precontracted to ~65% of maximal tension development. Maximal BK‐induced vasorelaxation was less (p<0.05) in arteries from I (68±8%; n=21 arteries, 195±20 µm i.d.) vs. NI (87±3%; n=33 arteries, 213±17 µm i.d.) patients, while responses to SNP (~90%) were similar between groups. These findings indicate endothelial dysfunction is greater in I vs. NI patients at the time of LVAD implant. Next we assessed vascular reactivity in 6 I (58±6 y) and 4 NI (49±11 y) patients wherein samples were obtained at implant and explant (239±51 days later). Maximal BK‐induced vasorelaxation was greater (p<0.05) in coronary arteries from I patients at explant (87±6%, n=14 arteries, 305±30 μm i.d.) vs. implant (53±11%, n=12 arteries, 204±33 μm i.d.). Maximal BK‐induced vasorelaxation was similar in coronary arteries from NI patients obtained at explant (79±8%, n=7 arteries, 232±21 μm i.d.) and implant (72±17%, n=5 arteries, 135±13 μm i.d.). Responses to SNP were similar (~93%) at implant and explant for I and NI patients. Our data demonstrate that endothelial dysfunction in patients with advanced ischemic cardiomyopathy is improved through LVAD support.
Reversion from a high‐fat diet to a prenatal normal diet could delay the incidence of insulin resistance induced by postnatal high fat diet in female offspring (1072.2)
Authors: Keith Benjamin , Zhou Lun , Xie Linglin
Published: June 2021

Many studies have focused on the adverse effects of prenatal high fat diet (HFD) on offspring development, but few studies are aimed on evaluating how prenatal reversion to regular diet (ND) in obese subjects could affect the offspring high fat diet‐induced obesity (DIO). The female obese mice either continued a high fat diet during pregnancy till the end of lactation (HFD group), or switched from HFD to ND for four weeks and continued on ND during pregnancy till the end of lactation (HFD‐ND group). Offspring from both groups were subjected on HFD for 9 weeks after weaning. By the end of the week 9, we found that prenatal HFD‐ND differentially affects the male and female offspring with a postnatal HFD. This is evidenced by slower weight gain, lower weight of the liver, the subcutaneous and the visceral fat in HFD‐ND female offspring compared to the HFD female offspring, but not in HFD‐ND male offspring vs. HFD male offspring. Only HFD‐ND female offspring failed to develop insulin resistance after nine weeks postnatal HFD. This result was not caused by the differential consumption of male and female offspring via evaluating the food consumption. We further found that the female HFD offspring developed inflammation in liver tissue marked by increased macrophage infiltration comparing to the HFD‐ND female offspring. Our results demonstrated that maternal reversion from a HFD to a ND could affect the onset of DIO in female offspring.

Grant Funding Source: Supported by the University of North Dakota faculty seed money
Impaired autonomic regulation in hyperglycemia and cardiovascular dynamics during autologous blood donation (1072.7)
Authors: Kamakura Miho , Kanno Emi , Takahashi Masako , Maruyama Ryoko
Published: June 2021

Hyperglycemia has been reported as a risk factor for autonomic dysfunction. However, the changes in autonomic nerve activity that occur in hyperglycemic patients during blood volume reduction are unclear. This study aimed to investigate the impact of hyperglycemia (HbA1c 蠅 6.5%) on autonomic nerve activity and cardiovascular dynamics during blood volume reduction (300‐400 mL), by using autologous blood donation as a model of mild blood loss.

We compared the impact of hyperglycemia and non‐hyperglycemia on heart rate variability, including circulatory regulation, in 17 patients (mean age 60.9 ± 13.6 years) with no circulatory, respiratory, or cranial nerve disease.

During autologous blood donation, none of the patients experienced significant changes in blood pressure or heart rate. In non‐hyperglycemia, the low frequency/high frequency component ratio (LF/HF) significantly increased (p < 0.05) and HF decreased during autologous blood donation. In hyperglycemia, LF/HF and HF responses were lower than in non‐hyperglycemia.

These results show that hyperglycemia impaired autonomic regulation during a blood volume reduction of approximately 10% of the circulatory blood volume. This suggests that circulatory failure may be more common in hyperglycemic patients than in non‐hyperglycemic patients during moderate or severe blood volume reduction.
From pre‐clinical data to the clinics: identification of circulating inflammatory mediators as potential biomarkers for heart failure (1073.6)
Authors: Altara Raffaele
Published: June 2021

Inflammatory mediators (IMs) play a pivotal role during cardiac remodeling. In our study we focused on circulating IMs which might be used as biomarkers.

In rodents with cardiac hypertrophy and permanent myocardial ischemia we showed a circulating inflammatory profile with a common increase of 4 IMs in the onset of heart failure (HF).

To translate this finding to human HF, we established the baseline values of these IMs in healthy people. Thirty healthy volunteers were selected with no known inflammatory condition. Via a membrane‐based assay, we observed no consistent differences for ~40 inflammatory analytes among gender, sample type and time of collection. Thus, we proceeded to determine the circulating IMs in an age‐matched cohort of 30 HF patients.

Interestingly, two of the four IMs from our animal models had higher concentrations in HF patients when compared to healthy controls. Besides, these IMs have never been investigated in this setting before. Furthermore, a principal component analysis of the two groups (controls + HF patients) illustrated that one of the IMs was optimally separating the two groups on the base of component 1.

In conclusion, the two IMs discovered in pre‐clinics are upregulated in HF patients. Although this first set of results originates from a relatively small sample size, it is particularly encouraging that they might be biomarker candidates for prognostics and diagnostics of HF.

Grant Funding Source: Supported by the CTMM and the Dutch Heart Foundation (TRIUMPH).
Suppressor of cytokine signaling 3 exerts divergent local vs systemic effects in angiotensin II‐induced endothelial dysfunction (1074.6)
Authors: Li Ying , Kinzenbaw Dale , Modrick Marry , Faraci Frank
Published: June 2021

Angiotensin II (Ang II) plays a major role in vascular disease and hypertension, in part, through the interleukin‐6/STAT3 pathway. Pharmacological and genetic methods were used to investigate the role of SOCS3, a negative regulator of STAT3, in vascular disease. To examine direct effects of Ang II, we incubated carotid arteries for 22 hrs, then examined endothelial function using acetylcholine (Ach). Relaxation to Ach was similar in all arteries incubated with vehicle. A low concentration of Ang II (1 nmol/L) did not affect Ach‐induced vasodilation in wild‐type (WT) mice, but reduced that of SOCS3 haplodeficient (SOCS3+/‐) mice by ~50% (P<0.05). This Ang II‐induced impairment was prevented by inhibitors of STAT3, IL‐6, NF‐κB, or a scavenger of superoxide. Responses to nitroprusside were similar in all groups. Ang II type 1 receptor (AT1R) mRNA levels were increased ~2 fold in SOCS3+/‐ mice. In an in vivo model of Ang II‐dependent hypertension, systemic Ang II (1.4 mg/kg per day) infusion for 14 days reduced Ach‐induced vasodilation in both carotid and resistance arteries in brain from WT mice by ~60% (p<0.05). Surprisingly, deficiency in SOCS3 prevented the majority of Ang II‐induced endothelial dysfunction in both vessels, without affecting the pressor response to Ang II. These data suggest SOCS3 plays a divergent role in local versus systemic effects of Ang II on endothelial function.

Grant Funding Source: supported by the NIH (HL‐62984, and HL‐113863), the Department of Veterans Affairs (BX001399), and t
Increased Ca2+‐activated Ca2+ influx and impaired Ca2+ buffering in coronary smooth muscle from metabolic syndrome Ossabaw swine (1076.2)
Authors: McKenney Mikaela , Dineen Stacey , Noblet Jill , Tune Johnathan , Sturek Michael
Published: June 2021

Coronary smooth muscle (CSM) phenotype is affected by intracellular Ca2+ regulation and we have previously correlated changes in CSM Ca2+ signaling from Ossabaw swine with varying stages of coronary artery disease (CAD). Ossabaw swine are a model of metabolic syndrome (MetS) and CAD. Three year old pigs were fed an excess‐calorie, atherogenic or control diet for 6 months. CAD progression, coronary artery function, and CSM Ca2+ signaling were assessed. MetS coronaries had advanced, lipid‐laden atherosclerotic lesions containing calcium deposits, while lean had no CAD. In isometric tension studies diseased coronary rings generated significantly less tension than healthy rings in response to depolarization with 20 mM K+. CSM were enzymatically isolated and loaded with the Ca2+ indicator, fura‐2 AM. Diseased CSM showed less K+‐induced Ca2+ influx compared to healthy cells. Diseased cells recovered less from the cytosolic Ca2+ increase back to baseline, suggesting impaired Ca2+ buffering. In physiologic salt solution (PSS), there was no difference in peak Ca2+ transient elicited by caffeine‐induced intracellular Ca2+ store release. The caffeine‐induced Ca2+ transient in Ca2+‐free PSS, which represents exclusively sarcoplasmic reticulum (SR) Ca2+ release, was decreased in diseased cells. Taken together, these data suggest that lesser SR Ca2+ release elicited greater Ca2+‐activated Ca2+ influx in diseased CSM. After caffeine challenge healthy CSM buffered Ca2+ significantly below basal Ca2+ compared to diseased CSM. Overall, the data suggest impaired CSM SR Ca2+ buffering, decreased SR Ca2+ store, and increased Ca2+‐activated Ca2+ influx in CAD.

Grant Funding Source: Supported by NIH HL062552, HL092245, NIH/NCATS CTSI TL1 TR000162
Glucose‐6‐phosphate dehydrogenase is involved in regulation of arterial smooth muscle phenotype in metabolic syndrome (1076.5)
Authors: Joshi Sachindra , Alloosh Muhammad , Gupte Sachin
Published: June 2021

Rationale: Coronary artery undergoes remodeling in metabolic syndrome that increases the risk of developing cardiovascular diseases. However, the effects of metabolic syndrome in the remodeling of the coronary artery are not clearly understood. Recently we have shown that Glucose‐6‐Phosphate Dehydrogenase (G6PD) activity is involved in regulation of vascular smooth muscle phenotype. Therefore, we hypothesize that G6PD activity is involved in regulation of arterial smooth muscle phenotype in metabolic syndrome.

Methods: To test this hypothesis we assayed G6PD activity in coronary arteries of pig model of metabolic syndrome (obese and lean) and in left internal mammary/radial arteries of human with metabolic syndrome (obese‐diabetic and obese‐non‐diabetic). We also assayed the markers of smooth muscle phenotype in these arteries.

Results: G6PD activity was increased (P<0.05; N=3) in arteries of obese‐diabetic (0.44±0.08 nmol/min/mg protein) as compared to obese‐non‐diabetic (0.13±0.03 nmol/min/mg protein) patients. Similarly, G6PD activity was also increased (P<0.05; N=10‐12) in the arteries of obese (2.9±0.8 nmol/min/mg protein) as compared to lean (1.2±0.5 nmol/min/mg protein) pigs. Interestingly, we also found that the myosin heavy chain ‐ a gold standard marker of smooth muscle phenotype was downregulated in obese‐diabetic human and obese pig arteries as compared to arteries of obese‐non‐diabetic humans and lean pigs. Similarly, myocardin levels were also decreased.

Conclusion: It appears that maladaptation of glucose metabolism and increased G6PD activity is involved in the regulation of arterial smooth muscle phenotype in metabolic syndrome.

Grant Funding Source: NIHHL085352
Omental fat from obese and obese diabetic patients dys‐regulates vascular function by NF‐κB, PARP‐1 and interleukin 12‐dependent mechanism (1076.7)
Authors: Kassan Modar , Ait Aissa Karima , Haynes Bronson , Fontana Mark , Dobrian Anca , Wohlgemuth Stephen , Trebak Mohamed , Belmadani Souad , Matrougui Khalid
Published: June 2021

Background: The abdominal adipose omental tissue in obese and obese diabetic patients is a major risk factor for cardiovascular diseases. Here we determined the role of interleukin 12 (IL‐12), NFκB and PARP‐1 in omental tissue‐induced vascular dysfunction in obese, obese type 2 diabetic (T2D) patients, and type 2 diabetic (db‐/db‐) mouse.

Methods & results: Mesenteric resistance arteries (MRA) from C57/BL6 and IL‐12 receptor‐/‐ mice were mounted in a wire myograph and incubated with omental fat from obese, obese T2D patients, db‐/db‐ and db‐/db‐p50NFκB‐/‐, db‐/db‐PARP‐1‐/‐ and C57/BL6 mice treated with and without NFκB (DHMQ), PARP‐1 (ABT‐888) inhibitors and IL‐12 receptor antagonist. The endothelium‐dependent relaxation was not affected. However, we observe an increase in phenylephrine‐(PE) and thromboxane‐(U46619)‐induced contraction in MRA incubated with omental fat from obese, obese T2D patients and db‐/db‐ mice. The contraction was potent with omental fat from obese T2D than obese patients. Interestingly, ABT‐888, DHMQ, IL‐12 receptor antagonist and MRA from IL‐12 receptor‐/‐ significantly reduced the exacerbated PE and thromboxane‐induced contraction in MRA incubated with omental fat from obese, obese T2D patients or db‐/db‐. Importantly, PE and thromboxane‐induced contraction was significantly reduced when MRA from db‐/db‐p50NFκB‐/‐ or db‐/db‐PARP‐1‐/‐ double knockout mice were incubated with omental fat from obese, obese T2D patients and db‐/db‐ mice. These results were associated with augmented NFkB and PARP‐1 activity and IL‐12 content in omental fat from obese, obese T2D patients and db‐/db‐ mice compared to control. IL‐12 content was significantly reduced in omental fat incubated with NFkB and PARP‐1 inhibitors.

Conclusion: The present study provide evidence that adipose omental tissue in obese, obese T2D patients and T2D mouse impairs vascular function by IL‐12, NFκB and PARP‐1‐dependent mechanisms
Arterial smooth muscle cells express segment a‐deficient TMEM16A channels (1077.7)
Authors: Burris Sarah , Jangsangthong Wanchana , Leo M. Dennis , Narayanan Damodaran , Jaggar Jonathan H.
Published: June 2021

Transmembrane protein A (TMEM16A) Cl‐ channels are expressed in arterial smooth muscle cells (SMCs) where they regulate physiological functions, including contractility and proliferation. TMEM16A alternative splice variation, which can occur at segments a, b, c, and d can alter channel biophysical properties. Identifying TMEM16A splice variants expressed in arterial SMCs should better define mechanisms by which these channels control vascular function. Our data, obtained using RT‐PCR, indicate that arterial SMCs express TMEM16A channels deficient in segment a, which removes 116 amino acids of the proximal N‐terminus. In contrast, arterial SMC TMEM16A channels contained segments b (exon 6b), c (exon13), and d (exon 15). Western blotting and whole‐cell patch clamp electrophysiology experiments demonstrated that vectors encoding segment a‐deficient TMEM16A channels (bcd) produced less protein and generated smaller whole‐cell currents than those expressing full‐length (abcd) channels in HEK293 cells. Lower TMEM16Abcd protein and currents did not occur due to attenuated transcription, elevated protein degradation or diminished surface trafficking. We are performing further experiments to test the hypothesis that segment a‐deficiency inhibits TMEM16A translation in arterial smooth muscle cells. NIH/NHLBI

Grant Funding Source: NIH/NHLBI
Cardiomyocyte Ogt is essential for maintaining cardiac function (1078.1)
Authors: DeMartino Angelica , Watson Lewis , Long Bethany , Brittian Kenneth , Readnower Ryan , Brainard Robert , Cummins Timothy , Annamalai Lakshmanan , Hill Bradford , Jones Steven
Published: June 2021

O‐GlcNAc transferase (OGT) catalyzes the post‐translational protein modification, O‐GlcNAc, in response to acute stress. We previously demonstrated a role for O‐GlcNAc in acute cardioprotection and heart failure; however, its roles in the developing heart and in the adult, non‐infarcted heart remain unknown. We hypothesized that constitutive, cardiomyocyte‐specific OGT ablation (c‐cmOGT KO) would impair cardiac function as the heart transitioned from a low afterload in utero to high as a neonate. Indeed, c‐cmOGT KO mice had impaired survival, were runted compared to littermates, had cardiomegaly, displayed marked cardiac fibrosis, and had dramatically depressed ventricular function. Histology revealed pathology in the endoplasmic reticulum (ER) and immunoblotting indicated ER stress (Grp78 and PDI) in c‐cmOGT KO hearts. Heterozygous OGT deficient mice were also generated and, unlike the acute, severe heart failure observed in the c‐cmOGT KO, heterozygous mice experienced a progressive cardiomyopathy, suggesting a potential dose‐dependent effect. Finally, we inducibly‐deleted cardiomyocyte OGT via the MerCreMer transgene. Although there were no significant defects apparent within the first few weeks, ventricular function significantly and progressively declined several weeks following deletion. These results indicate a critical, yet dynamic, role for OGT in developing and mature hearts.

Grant Funding Source: Supported by the NIH and AHA
A systematic review of fetal genes as biomarkers of cardiomegaly in rodent models of diabetes (1078.3)
Authors: Cox Emily , Marsh Susan
Published: June 2021

Pathological cardiac hypertrophy activates a suite of genes called the fetal gene program (FGP). Pathological hypertrophy occurs in diabetic cardiomyopathy (DCM); therefore, the FGP is widely used as a biomarker of DCM in animal studies. However, it is unknown whether the FGP is a consistent marker of hypertrophy in rodent models of diabetes. Therefore, we analyzed this relationship in 94 systematically selected studies. Results showed that diabetes induced with cytotoxic glucose analogs such as streptozotocin was associated with decreased heart mass, but genetic or diet‐induced models of diabetes were significantly more likely to show cardiac hypertrophy (p<0.05). Animal strain, sex, age, and duration of diabetes did not moderate this effect. There were no correlations between the heart weight:body weight index and mRNA or protein levels of the fetal genes α‐myosin heavy chain (α‐MHC) or β‐MHC, sarco/endoplasmic reticulum Ca2+‐ATPase, atrial natriuretic peptide (ANP), or brain natriuretic peptide. The only correlates of non‐indexed heart mass were the protein levels of α‐MHC (Spearman’s ρ=1, p<0.05) and ANP (ρ=‐0.73, p<0.05). These results indicate that most commonly measured genes in the FGP are confounded by diabetogenic methods, and are not markers of cardiomegaly in rodent models of diabetes.
Reduction of fibrosis in type 2 diabetes by (‐)‐epicatechin (1078.4)
Authors: Peltekian Lila , Brito Alfonso , Yamazaki Katrina
Published: June 2021

Fibrosis is the buildup of connective tissue, mainly collagen, thereby decreasing the contractility and the elasticity of the heart leading to heart failure. In this study we looked at the effects of (‐)‐epicatechin (EPI) on reducing the progression of type 2 diabetes and fibrosis in vivo. Type 2 diabetes was induced by feeding rats a high energy diet (HED) consisting of 10% lard and 20% glucose. After 4 weeks, a low dose streptozotocin (30 mg/kg) was given IP to cause partial dysfunction of pancreatic β‐cells and suppress insulin secretion. Control animals were maintained on normal chow and received an IP injection of vehicle (water). Animals were also treated with EPI (1 mg/kg/day) or water by oral gavage. Results demonstrated that diabetic animals had significant weight gain (~44%) and increased blood glucose levels (519 mg/dL) compared to control (37% and 185 mg/dL, respectively). EPI significantly reduced changes in body weight (~33%) and blood glucose levels (351.2 mg/dL) compared to diabetic animals. Histological analysis showed elevated collagen levels in diabetic hearts compared to control and EPI‐treated animals. In conclusion, our results demonstrate the ability of EPI to reduce body weight, plasma glucose levels and fibrosis in type 2 diabetes.

Grant Funding Source: Support provided by CSU‐LSAMP from NSF HRD‐1302873 and Office of the Chancellor.
mTOR inhibition protects diabetic heart against ischemia/reperfusion injury through STAT3 activation (1078.5)
Authors: Das Anindita , Salloum Fadi , Durrant David , Samidurai Arun , Kukreja Rakesh
Published: June 2021

Objective: Diabetes is a major risk factor for myocardial infarction. Rapamycin, mTOR (mammalian target of rapamycin) inhibitor, preserves cardiac function and reduces infarct size after myocardial infarction through STAT3 activation. Recent evidence showed decreased levels of activated STAT3 in diabetic heart. Considering the cardioprotective role of STAT3, we tested the hypothesis that chronic treatment with Rapamycin would protect the diabetic heart against ischemia/reperfusion (I/R) injury through STAT3 signaling.

Methods and Results: Adult male wild type or db/db mice were treated daily for 28 days with vehicle (DMSO) or Rapamycin (0.25 mg/kg/day, i.p.). Following treatment, the hearts were subjected to global I (30 min) and R (1 hour) in Langendorff mode. Rapamycin treatment increased STAT3 phosphorylation, reduced infarct size following I/R (Fig. 1A), and protected adult cardiomyocytes following simulated ischemia/reoxygenation in vitro. Downstream targets of STAT3, miRNA‐17 and ‐20a, part of miRNA‐17‐92 cluster, were induced in heart (Fig. 1B, C) and cardiomyocytes derived from Rapamycin‐treated db/db mice. Rapamycin treatment also caused reduced expression of pro‐apoptotic prolyl hydroxylase Egln3/PHD3, a target of miR‐17/20a (Fig. 1D). In addition, Rapamycin‐induced protection against I/R injury was abolished in cardiac‐specific STAT3‐deficient mice made diabetic with high fat diet (Fig. 1E).

Conclusion: We conclude that Rapamycin causes STAT3‐miRNA‐20a‐mediated suppression of Egln3/PHD3 that may be associated with cardioprotection against I/R injury in diabetic mice.

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Grant Funding Source: Supported by NIH HL51045, HL79424, HL118808
Cardiac responses to GLP‐1 receptor activation are impaired in the setting of metabolic syndrome (1078.7)
Authors: Conteh Abass , Goodwill Adam , Noblet Jill , Sassoon Daniel , Tune Johnathan , Mather Kieren
Published: June 2021

This study investigated the cardiovascular effects of the glucagon‐like peptide‐1 (GLP‐1) receptor agonist Exendin‐4 in lean vs. obese hearts. Left ventricular pressure‐volume relations were obtained following 24 hr intravenous infusion of saline‐vehicle or Exendin‐4 (30 fmol/kg/min) in lean (69 ± 4 kg) and obese (105 ± 2 kg) Ossabaw swine with metabolic syndrome (MetS). Measurements were obtained at rest, following 30 min occlusion of the left circumflex coronary artery, and following 2 hours of reperfusion. Baseline coronary flow, heart rate, and stroke volume were not different between vehicle‐treated lean and MetS swine. Exendin‐4 had no effect on end diastolic volume or stroke volume in lean or MetS swine. However, cardiac output and blood pressure were significantly increased relative to end‐diastolic filling volumes by Exendin‐4 administration in lean swine (P<0.05). Load independent assessment of cardiac inotropy revealed that Exendin‐4 increased the slope of the end systolic pressure volume relationship (ESPVR) from 2.9 ± 2.7 to 10.6 ± 2.4 mmHg/ml (p<0.05) in lean swine during ischemia. In contrast, Exendin‐4 had no effect on the relationship between cardiac output, blood pressure and end‐diastolic volume or on the ESPVR in MetS swine. These findings indicate that the cardiac inotropic actions of GLP‐1 receptor activation following ischemia/reperfusion injury are abolished in the setting of the metabolic syndrome.

Grant Funding Source: Supported by NIH HL117620; NIH HL117620‐S1
Neural programming of vascular maturation and effects of denervation (1079.13)
Authors: Reho John , Zheng Xiaoxu , Benjamin James , Fisher Steven
Published: June 2021

From birth through maturity the blood pressure in humans and animals steadily increases yet the basis of vascular maturation is unknown. The sympathetic nervous system innervates the mesenteric arterial tree post‐natally. We hypothesized that neural inputs program post‐natal maturation of regional circulations vascular smooth muscle (VSM). Chemical sympathectomy was achieved via 6‐hydroxydopamine initiated at PND1. Denervation in adult rats was achieved via disruption of the renal artery adventitia followed by a 10% phenol solution. Rat MA VSM matures from PND 12‐35 as evidenced by 1) 10‐50 fold induction of contractile protein expression via qPCR, including CPI‐17 2) 25‐50 fold induction of the α1‐adrenergic (Adra1), purinergic (P2RX1) and NPY (NPY1R) receptors that mediate VSM neural responses 3) switching of myosin phosphatase splice variant isoforms from E24‐ (LZ+) to E24+ (LZ‐). Denervation during development or in adults caused a reversion to a more immature VSM gene program. Vascular contractility via wire myography paralleled the changes in gene expression, with increased calcium sensitization during development that was inhibited by denervation. We propose that sympathetic neural inputs developmentally program MA VSM to capture control of vascular function in a feed forward manner. Removal of neural inputs programming VSM may contribute to the salutary effects of denervation in hypertension.

Grant Funding Source: HL066171
Contribution of vascular hyperpolarization to augmented skeletal muscle hyperemia during hypoxic exercise in humans (1079.20)
Authors: Racine Matthew , Crecelius Anne , Larson Dennis , Luckasen Gary , Dinenno Frank
Published: June 2021

Exercise hyperemia during hypoxia is augmented relative to normoxia. At moderate exercise intensities, nitric oxide (NO) and vasodilating prostaglandins (PGs) explain ~50% of this response, yet the remaining signaling mechanisms remain unclear. We hypothesized that vascular hyperpolarization via activation of inwardly rectifying potassium (KIR) channels and Na+/K+‐ATPase accounts for the remaining ~50% of the augmented hyperemia. In 10 young adults, we measured forearm blood flow (FBF; Doppler ultrasound) during 5 min of rhythmic handgrip exercise at 20% maximal voluntary contraction in normoxia (NormEx) and isocapnic hypoxia (HypEx; O2 saturation 80%) before and after local combined inhibition of NO synthase (L‐NMMA), cyclooxygenase (ketorolac), KIR channels (barium chloride) and Na+/K+‐ATPase (ouabain). All trials were performed during local α‐ and β‐adrenoceptor blockade to isolate local vasodilation. In control conditions, FBF during HypEx was augmented vs. NormEx by 62±8 ml/min (P<0.05). In the blocked condition, this compensatory increase in FBF was only 29±6 ml/min (47±10% decrease), but O2 extraction was increased to maintain forearm VO2. These findings are similar to our previous observations with combined inhibition of NO and PGs alone, suggesting that vascular hyperpolarization via these pathways does not contribute to the augmented hyperemic response during hypoxic exercise.

Grant Funding Source: Supported by NIH award HL‐095573 (FAD)
The heart as an endocrine source of metabolic vasodilators (1079.26)
Authors: Kang Patrick , Chen Chwen‐Lih , Ohanyan Vahagn , Bratz Ian , Meszaros J. , Chilian William , Chen Yeong‐Renn
Published: June 2021

During heightened cardiac work, O2 consumption by the heart increases. This increase benefits energy production via mitochondrial e¯ transport, but the process of e¯ transport is not perfect and some e¯ “leak” from respiratory chain and reduce O2. This reduction yields O2˙¯, which reacts with thiol groups, iron, and is rapidly metabolized into H2O2 by mitochondrial superoxide dismutase (SOD2). To understand the potential systemic effects of the metabolic dilator, H2O2, we studied mice with cardiac specific SOD2 overexpression, which would increase the amount of H2O2 produced by the heart. To determine if this enhanced production of H2O2 results in a humoral action, i.e., systemic vasodilation, we first evaluated the effectiveness of SOD2 overexpression to effectively remove O2˙¯ from the mitochondria (EPR). SOD2 transgenic mice produced less O2, and had lower redox activity. Mitochondria of SOD2‐tg (vs WT) had lower GSSG concentration (decreased by 37.2±4.5%, GSH/GSSG ratio was increased by 66.7±6.8%). EPR analysis of the isolated mitochondria showed significant decrease of semiquinone in the SOD2‐tg vs WT at the Qi site (by 69.4±9.9%), and a diminished complex I protein thiyl radical(s) in the mitochondria of SOD2‐tg. These results support a more reducing milieu in the mitochondria of the SOD2‐tg heart. Cardiac mitochondria isolated from SOD2‐tg exhibited no significant differences in the respiratory control index between WT and SOD2‐tg (6.30.3 vs. 5.70.5, p>0.05). These results support the concept that the SOD2 overexpression is effective and results in increased production of H2O2. Moreover, arterial pressure was lower in the SOD2‐tg, but was normalized by iv injection of catalase, implying that the metabolic dilator, H2O2, “spilled” over inducing systemic vasodilation. In conclusion, SOD2 overexpression in myocytes triggers a more reductive milieu in murine heart enhancing the production of H2O2, which then acts as an endocrine dilator causing reductions in arterial pressure.

Grant Funding Source: NIH RO1 HL083237
Aging impairs myogenic adaptation to pulsatile pressure in mouse cerebral arteries (1079.7)
Authors: Springo Zsolt , Toth Peter , Tarantini Stefano , Tucsek Zsuzsanna , Cseplo Peter , Koller Akos , Sonntag William , Csiszar Anna , Ungavri Zoltan
Published: June 2021

Stability of myogenic tone of cerebral arteries is essential for adequate control over penetration of pressure (P) waves into the distal portion of the cerebral microcirculation (the resistance to flow is dominated by the fourth power of the internal vessel radius). Because aging promotes cerebromicrovascular injury, we tested the hypothesis that aging alters the myogenic response. P‐induced constriction of cannulated middle cerebral arteries (MCA) isolated from young (3 mo) and aged (24 mo) mice was assessed. Both young and aged MCAs developed similar myogenic tone in response to stepwise, steady‐state increases in intraluminal P. Young MCAs exhibited significant myogenic adaptation to sinusoidal pulsatile P (amplitude: 40 mmHg, freq:450/min). While in myogenically inactive MCAs each P pulse elicited a ~7% distension in synchrony with the pulsatile P, in young myogenically active MCAs the amplitude of the diameter changes induced by the P pulses in the autoregulated P range was significantly attenuated (~2%). The mean P‐myogenic tone curve was similar in young MCAs exposed to constant and pulsatile P. In aged MCAs the cyclic changes in diameter induced by the P pulses were increased (~4%) and development of myogenic tone in response to pulsatile P was impaired. Collectively, aging impairs myogenic adaptation of cerebral arteries to pulsatile P, which likely promotes the development of cerebral microbleeds and BBB disruption by allowing high P to penetrate the distal portion of the cerebral microcirculation.

Grant Funding Source: Supported by TÁMOP 4.2.4.A/2‐11‐1‐2012‐0001,SROP‐4.2.2.A‐11/1/KONV‐2012‐0024 and 0017,OTKA K‐108444
Mechanisms that couple histone modifications to transcription elongation and regulate transcription termination (108.2)
Authors: Arndt Karen , Shirra Margaret , Van Oss S. , Cucinotta Christine , Tomson Brett
Published: June 2021

During transcription elongation, multiple regulatory factors associate with RNA polymerase II and coordinate RNA processing and chromatin modification with transcript synthesis. The eukaryotic Paf1 complex (Paf1C) functions at the intersection of RNA synthesis and chromatin modification by traveling with RNA pol II at all active genes, facilitating conserved histone modifications, and stimulating the recruitment of factors important for RNA 3’‐end formation. Using budding yeast as a model system, we are employing a multidisciplinary approach of genetics, biochemistry, structural biology and genomics to dissect these functions of Paf1C. With respect to histone modifications, we are investigating how a 66 amino acid domain within the Rtf1 subunit of Paf1C can substitute for the entire complex in promoting histone modifications in vivo. We are also using a genetic approach to identify amino acids within the nucleosome itself that are important for Paf1C‐dependent histone modifications. In related work, we have shown a role for Paf1C‐dependent histone modifications in regulating RNA 3’‐end formation through the Nrd1‐Nab3‐Sen1 pathway. We are further exploring the functional importance of Paf1C in noncoding RNA synthesis through the use of specific yeast mutant strains and high‐resolution transcriptome analysis.
Hypoxia inducible factor‐1 alpha contributes to infarct size‐limiting effect of postconditioning afforded by epoxyeicosatrienoic acid analog in rat hearts. (1080.2)
Authors: Neckar Jan , Hsu Anna , Khan Abdul , Gross Garrett , Falck John , Imig John
Published: June 2021

The infarct size‐limiting action of a novel EET analog in reperfusion (pharmacological postconditioning) and the contribution of hypoxia inducible factor‐1 alpha (HIF‐1α) were investigated. Adult male SD rats were subjected to 30 min left coronary artery occlusion and 2 h of reperfusion. The endogenous EET, 14,15‐EET (2.5 mg/kg iv) or the EET analog, EET‐B (2.5 mg/kg iv) administered 5 min before reperfusion reduced infarct size expressed as a percentage of the area at risk (AR) by 29 and 33%, while their co‐administration did not provide stronger effect. On the other hand, EET antagonist 14,15‐EEZE (2.5 mg/kg iv) and HIF‐1α inhibitors, 2‐methoxyestradiol (2.5 mg/kg iv) and acriflavine (2 mg/kg iv) completely abolished the protective effect of EET‐B. In immunohistology, HIF‐1α signal markedly increased in the AR compare to non‐ischemic septum at the end of ischemia (9.3±1.1 vs 0.3±0.1%). After 20 min and 2 h of reperfusion, HIF‐1α immunoreactivity in AR decreased to 2.4±0.5 % and 1.9±0.4%, respectively in the controls. EET‐B administration blunted the decrease of HIF‐1α immunoreactivity in ischemized tissue in both time‐points of reperfusion (7.8±0.7 and 6.4±1.4%, respectively). In conclusion, EET‐B provides strong postconditioning protection against myocardial infarction in rats. We suggest that increased HIF‐1α level plays an important role in this cardioprotective mechanism.
Levosimendan preserves systolic and diastolic function in rats with volume overload heart failure through myofilament Ca2+ sensitization and regulatory protein phosphorylation (1081.4)
Authors: Lewis Kristin , West T. , Zhang Xiaojin , Trask Aaron , Cismowski Mary , de Tombe Pieter , Sadayappan Sathivel , Lucchesi Pamela
Published: June 2021

Objectives. This study investigated whether early intervention with the myofilament Ca2+ sensitizer levosimendan (Levo) could preserve cardiac function in aortocaval fistula (ACF)‐induced volume overload (VO). Methods and Results. ACF or sham surgery was performed in male Sprague‐Dawley rats (200‐240g) 4 weeks prior to initiating treatment with Levo (1 mg/kg/day in drinking water) or vehicle (Veh; water) for 4 weeks. Even with continued VO and compared with ACF‐Veh, Levo improved systolic (%FS, Ees, PRSW; 41.3 vs 32.2%, p<0.0001; 0.654 vs 0.392 mmHg/µL, p<0.05; 113.6 vs 60.2 mmHg, p<0.05, respectively) and diastolic (tau, dP/dtmin; 8.9 vs 10.8 msec, p<0.05; ‐7626 vs ‐5739 mmHg/sec, p<0.001, respectively) function without significant LV remodeling. Additionally, Levo treatment resulted in 1) improved myofilament Ca2+ sensitivity without significantly affecting the amplitude and kinetics of the myocyte intracellular Ca2+ transient; 2) preserved in vivo β‐adrenergic responsiveness; and 3) increased phosphorylation of cMyBP‐C Ser‐273 and Ser‐302 and cTnI Ser‐23/24 that was associated with the improved diastolic function. Levo did not increase α‐MHC/β‐MHC mRNA compared with Veh. Conclusion. These results demonstrate that myofilament regulation in VO HF preserves systolic and diastolic function and may provide a new therapeutic target in patients with volume overload heart failure.

Grant Funding Source: Supported by: R01 HL‐056046 (to PAL), R01 HL‐62426 (to PDT), R01 HL105826 and K02 HL 114749 (to SS)
Oxidative stress‐induced changes in nitric oxide availability contribute to increased pulmonary microvascular tone in a mouse model of Alzheimer's disease (1082.2)
Authors: Roberts Andrew , Jagadapillai Rekha , Vaishnav Radhika , Friedland Robert , Sachleben Leroy , Gozal Evelyne
Published: June 2021

Inflammation and oxidative stress are well‐known components of Alzheimer's disease (AD) that cause cardio‐respiratory abnormalities. To determine if AD‐induced inflammation occurs in the lung and affects its function, we hypothesized that these processes of AD cause pulmonary microvascular dysfunction by decreasing lung nitric oxide (NO) bioavailability. We assessed pulmonary involvement in an established mouse transgenic AD model expressing the human APP gene 770 isoform with the Swedish, Dutch and Iowa mutations, and in wild type (WT) controls. Mice 7‐20 months old were used, since at these ages AD model mice have microvascular injuries. Effects of acute NO synthase (NOS) inhibition with L‐NAME on pulmonary microvascular diameter were examined in the right lung of anesthetized, open chest AD and WT mice by intravital microscopy while the lungs were statically inflated with O2. Arteriolar constriction to L‐NAME was blunted in AD mice compared to WT controls. Lung immunohistochemistry showed a significant increase in superoxide production and inducible NOS (iNOS) in the AD model mice. Our data suggest that despite iNOS induction, superoxide formation decreases lung NO bioavailability in AD, resulting in changes in pulmonary vascular tone. The loss of this vasodilator influence indicates cardiovascular dysfunction may be initiated in AD through a generalized inflammatory process.

Grant Funding Source: Supported by AG017173 to RPF
AT1 receptor blockade abolishes metabolic and cardiovascular programming effects of neonatal obesity and undernutrition (1085.5)
Authors: Mecawi André , Marangon Paula , Moraes Davi , Bonagamba Leni , Machado Benedito , Elias Lucila , Antunes‐Rodrigues José
Published: June 2021

The variation of litter size from rodents in the early days of life, which results in neonatal overfeeding or undernutrition, is a very useful model for the obesity study since programs the animals to become obese adults. Moreover, several studies have demonstrated the importance of the angiotensin II (ANG II) in the pathophysiology of obesity and its correlation with cardiovascular diseases. Thus, we aimed to study the role of type 1 ANG II receptors (AT1) on metabolic and cardiovascular effects induced by neonatal obesity or undernutrion programming. For this, the litters were divided into 3 groups: Normal Litter (NL, 10 pups), Small Litter (SL, 3 pups) and Large Litter (LL, 16 pups). The reduction and increment of the litter size increased and decreased , respectively, the body weight (BW) gain in SL (~25%) and LL (~19%) groups, at the weaning (21st day). Despite adult (60 days) SL rats remained with elevated BW, no differences were observed between LL and NL groups. Plasma ANG II levels are higher in both SL (~40%) and LL (~120%) groups in relation to NL at the weaning, with no differences in the adulthood. Both SL and LL groups showed an increase in visceral adipose tissue (~34 and 19%), obesity Lee index (~4 and 3%), and mean arterial pressure (~12 and 10%) in relation to the NL group, respectively. The treatment with losartan (AT1 receptor antagonist) in the drinking water (~ 8 mg / kg / day) from 30 to 60 days of age reduced the visceral adipose tissue weight, Lee index and mean arterial pressure from SL and NL groups. Our data suggest that AT1 receptors are essential for the programming of obesity and hypertension due to neonatal overnutrition or undernutrition.

Grant Funding Source: Supported by FAPESP