bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Epigenetic Mechanisms and Matrix Remodeling Enzymes in Oxidative Stress Induced Loss of the Microvascular Endothelial Glycocalyx
Authors: Ali Mohamed M , Mahmoud Abeer M , Phillips Shane A 
Published: November 2023

The integrity of endothelial glycocalyx is crucial for normal endothelial function and endothelial response to shear stress. Endothelial glycocalyx also tethers and concentrates the extracellular superoxide dismutase (ecSOD) which protects the endothelium against the oxidative damage of reactive oxygen species (ROS). Degradation of endothelial glycocalyx results in endothelial dysfunction and vascular remodeling. The proteolytic enzymes Matrix Metalloproteinases (MMPs) are capable of disrupting endothelial cell surface proteins such as syndecans resulting in derangements of endothelial glycocalyx. We sought to 1) test the role of MMPs and oxidative stress in disrupting the endothelial glycobiology 2) to determine the role of oxidative stress in the epigenetic regulation of this response. To this end, we experimentally induced oxidative stress in human adipose microvascular endothelial cells (HAMECs) in the presence or absence of exogenous hydrogen peroxide (H2O2, 2×10−4 mol/L; 4 hours) and endogenous oxidative stress buthionine sulfoximine (BSO; 10−3 mol/L) and MMP inhibitors. We found that either H2O2 or BSO, induced a 2–3 fold increase in MMPs (MMP1, MMP2 and MMP3) and a 3–5 fold increase in ADAMs (ADAM10 and ADAM17). Consequently, there was a reduction in protein levels of syndecan‐1 and ecSOD in the total cell lysate and increases in levels of syndecan‐1 ectodomain and ecSOD in cell culture media (4 folds and 5 folds, respectively) detected by immunoprecipitation and Western blotting. The upregulation of MMPS was accompanied by a decline of the mRNA and protein levels of their inhibitors, tissue inhibitors of MMPs (TIMPs; 2–3 fold). Interestingly, we found that the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA) (5×10−6 mol/L) normalized MMP expression and restored TIMP 1 and TIMP 3 after H2O2 or BSO. Pharmacological inhibition of MMPs using marimastat (50 μM) and lisinopril (10 μM) mitigated the effect of oxidative stress on the glycocalyx. Using immunofluorescent labeled wheat germ agglutinin, we found that lisinopril and marimastat effectively restored the cell surface density of heparan sulfate glycosaminoglycans (HS‐GAGs), Syndecans and ecSOD on the endothelial cell surface. Lastly, we found that lisinopril decreased HDAC mRNA expression induced by H2O2 suggesting an epigenetic mechanism of lisinopril on responses to oxidative stress. In conclusion, our findings suggest that oxidative stress induced loss of the endothelial glycocalyx involves epigenetic regulation of matrix metalloproteinases that results in the shedding of ecSOD and syndecans. These data shed light on a therapeutically targetable epigenetic regulatory mechanism by which oxidative stress may induce vascular remodeling and endothelial dysfunction.Support or Funding InformationNIH RO1s HL095701, HL095701‐01A2S (SAP), American Heart Association Grant 15POST24480172 (AMM)
Xanthine Oxidase Inhibition Decreases Vascular Stiffness in Western Diet Fed Male and Female Mice
Authors: Aroor Annayya , Habibi Javad , Jia Guanghong , Manrique Camila , Sun Zhe , Martinez‐Lemus Luis , Meininger Gerald , Sowers James 
Published: November 2023

Endothelial and arterial stiffness play a central role in the development and progression of cardiovascular disease. Obesity and diabetes are associated with development of premature arterial stiffness. We have recently reported that male and female mice fed a diet high in fat and refined carbohydrates including fructose (western diet – WD) develop premature cardiac and vascular stiffness. In this regard, excess uric acid formed from excess fructose ingestion is emerging as a risk factor for vascular stiffness and vascular injury. We hypothesized that increased tissue xanthine oxidase activity and increased hepatic production of uric acid is associated with increased vascular stiffness and vascular dysfunction in WD fed males and females. Four week‐old C57BL6/J male and female mice were fed a WD with excess fat (46%) and fructose (17.5%) for 16 weeks with or without access to allopurinol in the drinking water (125mg/L), a potent xanthine oxidase inhibitor. Plasma uric acid levels were increased in plasma from WD male and female mice and these levels were normalized by allopurinol. Endothelial stiffness as determined by atomic force microscopy, was significantly increased in WD fed mice and this was significantly decreased by allopurinol administration. Increased endothelial stiffness was associated with increased fibrosis and vascular oxidative stress as determined by 3‐nitrotyrosine staining and this was prevented by allopurinol. Allopurinol treatment significantly attenuated WD induced increases in xanthine oxidase activity in aorta. Allopurinol also improved WD induced impairment of endothelial mediated vascular relaxation. WD feeding was associated with increased macrophage inflammatory response (M1 polarization) in aorta that was ameliorated by allopurinol. Taken together, these findings support that increased production of uric acid and enhanced xanthine oxidase activity in aorta promote vascular oxidative stress, macrophage inflammatory responses and vascular fibrosis/stiffness. We posit that increased cardiovascular xanthine oxidase activity associated with consumption of a WD plays a central role in the increased oxidative stress, inflammation and fibrosis.Support or Funding InformationNIH R01 HL107910‐01 for J.R.S and the Veterans Affairs Merit System (Grant 0018) for J.R.S
Recovery of Ischemic Infarction by Trientine‐induced Copper Redistribution in the Heart of Rhesus Monkeys
Authors: Han Pengfei , Ding Xueqin , Fu Chunyan , Zhang Xianyu , Zhang Wenjing , Xiao Ying , Wang Hongge , Sun Xiaorong , Fan Suzhen , Kang Y. James 
Published: November 2023

Persistent myocardial ischemic insult leads to copper (Cu) efflux from the heart and Cu elevation in the plasma, in association with significantly decreased capillary density. Cu is essential for angiogenesis. We observed that Cu‐trientine complex increased Cu uptake by primary cultures of neonatal rat cardiomyocytes subjected to hypoxia. The present study was undertaken to test the hypothesis that Cu redistribution to the heart by trientine can improve recovery of myocardial ischemic infarction. Male Rhesus monkeys of 2–3 years old were subjected to coronary artery ligation to induce myocardial ischemia. One year after the operation, myocardial infarction and dysfunction were detected by MRI and echocardiography. Trientine at a dose of 18 mg/kg a day was administered orally for eight weeks. At the end of the dose regiment, Cu concentrations were significantly elevated in the infarct area and border zone of the ischemic hearts, along with a decrease in plasma Cu concentrations compared to the untreated group. The angiogenesis factors including vascular endothelial growth factor (VEGF), VEGF receptor‐1 (VEGFR‐1), and other relevant factors were activated by the trientine treatment. Along with these changes, myocardial infarct size was significantly decreased and the density of myocardial microvessels was significantly increased. In addition, cardiac function was significantly improved, as evidenced by increased ejection fraction (EF) value. This study thus demonstrates that trientine is capable of redistributing Cu to the heart under ischemic conditions leading to a recovery of myocardial injury and dysfunction in Rhesus monkeys.Support or Funding InformationThis study is upported by National Science Foundation of China (81230004 and 81300109).
Radiofrequency Renal Denervation Protects the Ischemic Myocardium
Authors: Gao Juan , Polhemus David J , Smart Frank , Lefer David J , Kapusta Daniel R 
Published: November 2023

The sympathetic nervous system plays a critical role in the pathogenesis of acute myocardial infarction (AMI) and heart failure. This study tested whether pre‐conditioning with radiofrequency renal artery ablation (RF‐ABL) protects the heart against myocardial ischemia/reperfusion (MI/R) in the setting of hypertension. Spontaneously hypertensive rats (SHR) received either bilateral RF‐ABL (n=14) or Sham‐ABL (n=14) (Biosense Webster Stockert 70 RF generator). Four weeks following treatment, hypertensive SHR were subjected to 30 minutes of left coronary artery occlusion. After 24 hours reperfusion, the myocardial infarct size/area‐at‐risk (AAR) were determined. In addition, the left ventricle (LV) was collected for measurement of nitric oxide (NO) metabolites, nitrite (NO2−) and S‐nitrosothiol (RSNO), and oxidative stress. RF‐ABL produced a significant decrease in myocardial infarct size per AAR compared to Sham‐ABL (26.8 vs. 43.9%) and lower plasma cardiac troponin‐I (6.8 vs. 10.3 ng/ml). Cardiac NO2− levels increased from 2.6 to 3.2 nmol/mg and RSNO levels increased from 0.5 to 1.1 nmol/mg following RF‐ABL. Myocardial oxidative stress was markedly attenuated as measured by 8‐Isoprostane, carbonyl content, and MDA levels. Greater transcription (RT‐PCR) of antioxidants, SOD1 and GPX‐1 were also observed following RF‐ABL. These findings translated to a significant increase in 24‐hr survival of RF‐ABL (13 of 14) as compared to Sham‐ABL (8 of 14) SHR to MI/R. Together, these findings demonstrate that in hypertensive SHR, RF‐ABL produced a sustained increase in myocardial NO bioavailability and attenuation of oxidative stress, both of which can contribute to preconditioning the myocardium against subsequent MI/R injury. These findings provide new insights into the remote cardioprotective effects of RF‐ABL in the setting of AMI.Support or Funding InformationBiosense Webster IIS‐175 to DRK & FS; P30 GM103514 to DRK. 1R01 HL092141, 1R01 HL093579, 1U24 HL 094373, & 1P20 HL113452 to DJL.
Hemodynamics and Premature Ventricular Beats in Conscious Rats with Acute Myocardial Infarction Treated with Pyridostigmine Bromide
Authors: Santos‐Almeida Fernanda Machado , Salgado Helio Cesar , Fazan Rubens 
Published: November 2023

We examined the effect of the acetyl‐cholinesterase inhibitor pyridostigmine bromide (PYR) on hemodynamics and arrhythmias in conscious rats after acute myocardial infarction (MI). Male Wistar rats were anesthetized (ketamine/xylazine) and implanted with subcutaneous electrocardiogram (ECG) electrodes, and catheters into the left femoral artery and vein. At the following day, under inhalatory anesthesia (isoflurane), animals were subjected to coronary artery ligation to induce acute MI in the anterior wall of the left ventricle. Control rats were submitted to fictitious coronary ligation (sham surgery). 20 and 120 min after MI, with the animals already recovered from anesthesia, they were treated with PYR (0.25 mg/kg, iv), or saline. The arterial pressure (AP) and ECG were continuously recorded between the third and fourth hour after acute MI. AP as found similar among groups (92±7, 92±10 and 97±8 mmHg). Heart rate (HR) was markedly higher in non‐treated (saline) infarcted rats (442±15 bpm) as compared to control (non‐infarcted) counterparts (389±10 bpm). PYR significantly reduced HR of infarcted rats (414±9 bpm), but it remained higher than non‐infarcted control rats. In addition, infarcted rats treated with PYR showed lower number of premature ventricular beats (0 to 99 events per hour) as compared to non‐treated group (1 to 169 events per hour). In conclusion, the treatment with PYR, on the first hours after MI, showed a protective effect preserving hemodynamics (bradycardic effect without changing AP), and also reducing the incidence of ventricular arrhythmias.Support or Funding InformationFAPESP, CNPq, FAEPA
Effect of Caffeine on Cardiac Tissue Metabolism in Rabbits
Authors: Alada Akinola Abdulrasak , Nabofa Williams Ejide 
Published: November 2023

Caffeine has been reported to influence skeletal muscle tissue metabolism at rest and during exercise (Goldstein et al 2010; Graham et al 1994). This study was designed to investigate the effect of caffeine on cardiac tissue metabolism in the rabbit.The study was carried out on adult male New Zealand rabbits (weighing 1.8–2.2Kg) divided into 3 groups (n=5). Group I rabbits were given 0.2ml/Kg of normal saline and served as control while groups II and III rabbits were administered with 2mg/Kg and 6mg/kg of caffeine respectively for 28 days. Blood samples (3.0ml/rabbit) were collected by retro orbital puncture to determine serum Myeloperoxidase (MPO) activity and nitrite concentration. The animals were sacrificed by cervical dislocation and cardiac tissue biopsies were collected on dry ice for biochemical and immunohistochemical analyses. Cardiac tissue glycogen concentration was determined with the aid of anthrone reagent. Cardiac tissue Carnitine Palmitol Transferase 1 (CPT1) activity and cAMP concentrations were determined by immunohistochemistry and colorimetry techniques respectively, with assay kits obtained from Biovision inc.The results showed that caffeine at 2mg/kg and 6mg/kg significantly inhibited MPO activity from 0.72±0.05 to 0.164±0.045 and 0.46±0.12 U/L respectively (p<0.05). Caffeine at 2mg/kg had no significant effect on serum nitrite concentration but at 6mg/Kg, caffeine significantly increased nitrite concentration from 28.01±6.53 to 45.25±3.88μM (p<0.05). Also caffeine at 2mg/kg and 6mg/kg increased cardiac tissue glycogen concentration from 15.62±0.73 to 40.69±6.35 and 38.82±6.91mg/100g, cAMP concentrations from 5.097±0.29 to 6.840±0.26 and 6.36±0.14 pmol/well and CPT1 activity from 18.3 to 20 and 25.2% respectively (p<0.05).In conclusion, this study demonstrates that caffeine exhibits strong effects on cardiac tissue metabolism thereby causing cardioprotection, cardiac hyperemia, glycogen sparing, increased cAMP concentration and cardiac utilization of fatty acids as source of energy.
Influence of the Cardiomyocyte Circadian Clock on Autophagy in the Heart
Authors: He Lan , Brewer Rachel , Shanmugam Gobinath , Rajasekaran Namakkal Soorappan , Darley‐Usmar Victor , Chatham John C , Zhang Jianhua , Young Martin E 
Published: November 2023

BackgroundIn addition to its roles during physiologic (e.g., fasting) and pathologic (e.g., ischemia) states, autophagy is critical for cellular ‘housekeeping’, playing an important role in the normal turnover of damaged proteins and organelles (e.g., mitochondria). Over the course of the day, cells/organs are subjected to profound fluctuations in energy supply/demand, as well as exposure to environmental stresses known to induce protein/organelle dysfunction. This is particularly true for the heart, whose workload and oxidative metabolism dramatically increase during the awake (versus sleep) period. Recent studies have shown that the cardiomyocyte circadian clock directly modulates myocardial processes in a time‐of‐day‐dependent fashion, including metabolism and contractile function. The importance of the cardiomyocyte circadian clock is highlighted by observations that genetic disruption of this mechanism in mice (i.e., cardiomyocyte‐specific BMAL1 knockout; CBK) results in age‐onset cardiomyopathy and premature death.HypothesisWe hypothesize that the cardiomyocyte circadian clock directly regulates autophagy in the heart (which might be important for the normal turnover of proteins/organelles).Methods and ResultsConsistent with time‐of‐day‐dependent oscillations in autophagy, the LC3II/I ratio and p62 protein levels both oscillate in the mouse heart over the course of the day; these oscillations occur in an antiphase manner (i.e., LC3II/I peaks during the light/sleep phase, whereas p62 peaks during the dark/awake phase). Somewhat surprisingly, time‐of‐day‐dependent oscillations in LC3II/I and p62 persist in CBK hearts. However, p62 protein levels are chronically elevated, whereas p62 mRNA are chronically decreased, in CBK hearts, suggesting a potential negative impact of circadian clock disruption on autophagic flux. Fasting‐induced stimulation of autophagy was therefore next investigated in control and CBK hearts. Despite persistent food withdrawal, autophagy markers exhibited time‐of‐day‐dependent oscillations in the fasted state; in the case of LC3II/I, oscillations in this marker were antiphase in hearts of fed versus fasted control mice. Importantly, fasting‐induced alterations in LC3II/I were significantly attenuated in CBK hearts. Key regulators of autophagy were subsequently investigated, revealing that phosphorylation of mTOR (marker of activation) was chronically elevated in CBK hearts, relative to littermate controls.SummaryThe cardiomyocyte circadian clock appears to be an important regulator of cardiac autophagy. We speculate that chronic impairment of autophagy in the heart following disruption of the cardiomyocyte circadian clock contributes to cardiomyopathy in CBK mice.Support or Funding InformationUAB School of Medicine Multi‐Investigator Pilot Grant;NIH R01 HL123574;NIH R01 HL122975
1,25‐Dihydroxyvitamin D Regulates Energy Substrate Metabolism to Reduce Triacylglycerol Accumulation in 3T3‐L1 Adipocytes
Authors: Larrick Brienna M , Kee‐Hong Kim , Donkin Shawn S , Teegarden Dorothy 
Published: November 2023

It is well established that vitamin D is sequestered in adipose tissue. Many studies have demonstrated vitamin D regulation of adipocyte differentiation, inflammation, and energy metabolism, highlighting the multifaceted role that vitamin D plays in adipose tissue physiology. However, whether vitamin D impacts lipid metabolism in terminally differentiated adipocytes is not yet known. To study this, 3T3‐L1 adipocytes were differentiated for 9 days, followed by stimulation with 1,25‐dihydroxyvitamin D (1,25(OH)2D, 10 nM) or vehicle for the times indicated. All data are normalized to protein content, determined using the bicinchoninic acid (BCA) assay. We previously demonstrated that 1,25(OH)2D, the bioactive vitamin D metabolite, stimulates a 21% reduction in TAG accumulation in differentiated 3T3‐L1 adipocytes after 4 days (p=0.01). This occurs despite a significant increase in fatty acid uptake, assessed using BODIPY FL C16, following 1–4 days of treatment (p<0.01), and with concomitant stimulation of PKA‐dependent lipolysis (p<0.01). In our current studies, we demonstrate that 1,25(OH)2D stimulates a 2.5‐fold increase in complete fatty acid oxidation (p<0.01), assessed by quantifying the production of 14CO2 from [1‐14C] palmitic acid. Further, 1,25(OH)2D stimulates slight inhibition of de novo fatty acid synthesis, evidenced by a 10% reduction in [13C2]acetate incorporation into palmitic, palmitoleic, stearic, and oleic acids (p=0.03), determined by liquid chromatography‐mass spectrometry (LC‐MS). Interestingly, D‐[U‐13C]glucose incorporation into these fatty acids was reduced by 30% in response to 1,25(OH)2D (p<0.01), indicating a reduced contribution of glucose as a substrate for de novo lipogenesis. Consistent with these results, the mRNA expression of pyruvate carboxylase (PC) is reduced by 40% in response to 1,25(OH)2D (p<0.01). PC catalyzes the carboxylation of pyruvate to form the tricarboxylic acid (TCA) cycle intermediate oxaloacetate, which may then be used to synthesize acetyl‐CoA and glycerol for triacylglycerol synthesis. In summary, 1,25(OH)2D stimulates fatty acid turnover in 3T3‐L1 adipocytes, characterized by stimulation of PKA‐dependent lipolysis and fatty acid uptake. Further, 1,25(OH)2D stimulates fatty acid oxidation, while reducing glucose utilization as a substrate for fatty acid synthesis, possibly through reduced flux of pyruvate into the TCA cycle. Collectively, these changes in lipid metabolism may contribute to the reduction in TAG accumulation that is stimulated by 1,25(OH)2D, and may be protective against excessive fat mass accumulation and associated metabolic disorders.Support or Funding InformationSupported by the Purdue University Center for Cancer Research: Obesity and Cancer Discovery Group (CA023168) and a Project Development Team within the ICTSI NIH/NCRR (UL1TR001108).
Lyophilized plasma prevents endothelial leak and improves oxygenation following traumatic hemorrhage
Authors: McCully Belinda H , Dean Rondi K , Connelly Christopher R , Martin David T , Perl Vicente J Undurraga , Watson Justin , Yonge Davis , Rick Elizabeth A , Baimukanova Gyulnar , Pati Shibani , Schreiber Martin A 
Published: November 2023

Lyophilized plasma (LP) reconstituted to 100% (1×LP) or 50% (2×LP) of its original volume is just as effective as fresh frozen plasma (FFP) in correcting hemodynamic instability and coagulopathy following traumatic hemorrhagic shock. Compared to transfusion with lactated Ringers (LR), FFP also prevents the endotheliopathy of trauma (EOT) following hemorrhagic shock by attenuating vascular endothelial leak, which prevents endothelial damage, edema and end organ injury. Whether LP acts similarly to FFP on the vascular endothelium in preventing EOT is not known. Therefore, we hypothesized that similar to FFP, 1×LP and 2×LP would minimize endothelial permeability and prevent pulmonary dysfunction following traumatic hemorrhage. To test this hypothesis, two experiments were performed. To test for endothelial permeability in vitro, human pulmonary endothelial cells (HPECs) suspended in growth media were treated with FFP, 1×LP or 2×LP. Increased trans‐endothelial membrane resistance (TEER) indicated decreased permeability and barrier function recovery. When HPECs were treated in 10% plasma, the rise in TEER from baseline was similar in cells treated with FFP (22%) and 2×LP (27%), and highest with 1×LP treatment (33%, p<0.05 vs FFP and 2×LP). However, when cells were treated with 2% plasma, the rise in TEER was highest in HPECs treated with 2×LP (29%), followed by FFP (22%), and 1×LP (15%). To test for pulmonary dysfunction in vivo, anesthetized female swine subjected to 30min of uncontrolled hemorrhage from Grade V liver injury were resuscitated with lactated Ringers (LR), FFP, 1×LP or 2×LP. Following conscious recovery, arterial blood gasses were measured 24hrs post‐injury. PaO2 and arterial O2 saturation were low in LR‐treated swine (n=1; PaO2:52mmHg, O2:87%), but improved with FFP (n=2, PaO2:77±1mmHg, O2:97±0%), 1xLP (n=2; PaO2:73±8mmHg, O2:97±1%) and 2×LP (n=2; PaO2:72±4mmHg, O2:96±1%). Only LR‐treated swine exhibited gross pulmonary vascular thrombosis. Take together, these data suggests that LP and FFP act similarly to prevent endothelial permeability and pulmonary dysfunction after injury. Further experiments are required to determine if LP performs as well as FFP to minimize EOT and organ damage following hemorrhagic shock.Support or Funding InformationThis work was funded by DOD US Army Grant W81XWH‐04‐1‐0114 (Schreiber)