bluuebunny/crossref_metadata_2025_split huggingface dataset:
A humanized anti‐cocaine monoclonal antibody alters cocaine metabolism in vivo and in vitro (848.3)
Authors: Edwards Kelli , Gooden Felicia , Dasenbrock Hanna , Tabet Michael , Ball William , Norman Andrew 
Published: June 2021

The recombinant humanized anti‐cocaine monoclonal antibody h2E2 is a lead candidate for pharmacotherapy of cocaine abuse. The pharmacokinetics of h2E2 (1.6 µmol/kg i.v.) in Swiss Webster mice was biphasic with a t1/2α of 1.2 hours and a t1/2β of 7.1 days, which indicates long‐lasting effects of h2E2. The low Vdss of 0.3 L/kg indicates that h2E2 is restricted to blood volume. In vivo, h2E2 caused a 19‐fold increase in plasma cocaine concentrations of an equimolar bolus dose of cocaine while inhibiting cocaine entry to the brain. It was hypothesized that the sequestration of cocaine by binding to h2E2 would also inhibit cocaine’s elimination and metabolism. However, the elimination rate of cocaine from plasma was enhanced while formation of the major cocaine metabolite in mice, ecgonine methyl ester (EME), decreased. To further investigate the effects of h2E2 on cocaine metabolism, in vitro experiments were performed in pH buffered mouse plasma. It was confirmed that the metabolism of cocaine by plasma butyrylcholinesterases to EME was inhibited by h2E2 in a dose‐dependent manner, which is consistent with in vivo observations. In conclusion, h2E2 protects cocaine from enzymatic hydrolysis to EME in vivo and in vitro. Further clarification of how cocaine is eliminated in vivo in the presence of h2E2 is underway.Grant Funding Source: Supported by NIH grant DP1DA031386 and the Dalton/Zannoni ASPET SURF Award.
Irreversible antagonism of receptors accelerates rat cocaine self‐administration behavior (848.4)
Authors: Dasenbrock Hanna , Zajac Danielle , Tsibulsky Vladimir , Norman Andrew 
Published: June 2021

A pharmacological model of self‐administration can be explained by the equation T=ln(1+Du/Dst)/k, where T=time between self‐administrations, Du=unit dose, Dst=satiety threshold, and k=first order elimination rate constant, predicts that increasing the pharmacodynamic parameter Dst accelerates self‐administration. Competitive dopamine receptor antagonists temporarily increase cocaine intake implicating dopamine receptor fractional occupancy by dopamine as a mediator of the behavior. Competitive antagonists do not alter the number of receptors, so they cannot be used to study spare receptors or to differentiate between fractional occupancy of receptors and absolute numbers of receptors occupied. Rats that reliably self‐administered cocaine were injected with the non‐specific irreversible antagonist, N‐Ethoxycarbonyl‐2‐ethoxy‐1,2‐dihydroquinoline (1mg/kg i.v.). Attempts were made every 8 hours to reinstate self‐administration and once reinstated self‐administration was regular but was initially 2‐fold higher than baseline with a concomitant increase in the satiety threshold. Over 6 days the rate slowly declined and eventually returned to baseline presumably due to receptor repopulation. This indicates that satiety threshold corresponds to a specific number of receptors occupied. Changes in the number of dopamine receptors are key regulators of addictive behavior.Grant Funding Source: NIH Grant DP1DA031386
Serotonin confessions of a dirty drug: dissecting the role of the serotonin transporter in cocaine action using SERT I172M mice (848.5)
Authors: Simmler Linda , Nackenoff Alexander , Stutz Sonja , Anastasio Noelle , Cunningham Kathryn , Blakely Randy 
Published: June 2021

Dopamine (DA) reuptake blockade is primary for the neuroplasticities that lead to cocaine addiction. However, cocaine is well known to inhibit the serotonin (5‐HT), DA, and norepinephrine transporters at relatively equivalent potencies. To elucidate the role of 5‐HT in cocaine action, we have developed a novel knock‐in (KI) mouse model wherein the Slc6a4 gene has been mutated to eliminate high‐affinity binding of cocaine to the 5‐HT transporter (SERT Met172). Using synaptosomes, we assessed the loss of high‐affinity recognition of cocaine and its analog RTI‐55 in the KI vs WT mice ex vivo. For these agents, we observed an 80‐ and 650‐fold reduction in potency for 5‐HT uptake inhibition, respectively. No change was seen for amphetamine and methylenedioxymethamphetamine (MDMA). We then measured the preferences of KI vs WT mice for cocaine in the 2‐bottle choice paradigm. KI mice exhibited a reduced preference in the first week of administration relative to WT animals. By week two, the KI mice demonstrated an exaggerated preference for cocaine vs WT littermates. These finding reveal a significant, time‐dependent, suppressive role of SERT antagonism in the drive of mice to continue to consume cocaine. Our studies are now being extended to other behavioral paradigms used to study cocaine action, as well as to an evaluation of molecular changes that derive selectively from SERT antagonism by cocaine.Grant Funding Source: Supported by NIMH award MH094527 and the Swiss National Science Foundation
Regulation of cGMP by glucose‐6‐phosphate dehydrogenase through PDE5 In coronary artery (849.2)
Authors: Lakhkar Anand , Joshi Sachindra , Gupte Sachin 
Published: June 2021

Our laboratory has demonstrated that glucose‐6‐phosphate dehydrogenase (Glc‐6‐PD), the rate‐limiting enzyme in the pentose phosphate pathway, is a novel regulator of vascular smooth muscle contraction and phenotype. Inhibition of Glc‐6‐PD increases the contractile phenotype of coronary and pulmonary arteries by partly activating protein kinase G (PKG) pathway. PKG is activated by cyclic GMP (cGMP), which is increased in response to atrial natriuretic peptide (ANP) or nitric oxide and by inhibition of phosphodiesterase 5 (PDE5). Recently, using a combination of co‐immunoprecipitation and mass‐spec approach, we discovered that Glc‐6‐PD and PDE5 forms a complex in the coronary artery. Therefore, we hypothesized that inhibition of Glc‐6‐PD increases cGMP levels (which activates PKG) by decreasing the activity of PDE5 in coronary artery. To test our hypothesis, we incubated bovine left anterior descending artery (LAD) with Glc‐6‐PD inhibitors, 6‐aminonicotinamide (6‐AN, 1 µM) and dehydroepiandrosterone (DHEA, 100 µM); PDE5 inhibitor, sildenafil (Sil, 10 µM); Sil+6‐AN; and Sil+DHEA, in‐vitro for 12 hr and measured cGMP levels. Surprisingly and contrary to our expectations, we found that 6‐AN and DHEA decreased basal cGMP levels by 52 and 65%, respectively, as compared to control. While Sil increased cGMP by 324%, 6‐AN and DHEA reduced Sil‐induced increase in cGMP (Sil+6‐AN; 184% and Sil+DHEA; 133%). In conclusion, our novel findings demonstrate that: 1] inhibition of Glc‐6‐PD increases PKG activity via a cGMP‐independent pathway, 2] Glc‐6‐PD interacts with PDE5, and 3] Glc‐6‐PD‐derived redox signaling is an inhibitor of PDE5. These findings suggest that in diabetes or metabolic syndrome increased redox signaling may counter‐intuitively decrease the efficacy of PDE5 blockers.Grant Funding Source: NIHHL085352
Proliferation suppression by thyroid hormone requires thyroid hormone receptor in fetal cardiomyocytes (850.1)
Authors: Chattergoon Natasha , Louey Samantha , Scanlan Thomas , Thornburg Kent 
Published: June 2021

Objectives: Ovine fetal cardiomyocyte (CM) maturation begins after 100 days gestation (dGA). At term (145dGA) ~60% of CMs are binucleated and cannot divide. Thyroid hormone (T3) rises near term and suppresses proliferation by insulin‐like growth factor‐1 (IGF‐1) in vitro. Despite T3 activation of extracellular regulatory kinase (ERK) and AKT we hypothesize that T3‐induced inhibition of proliferation is thyroid receptor (TR) mediated and reversed by the TR antagonist, NH3. Methods: Fetal CMs were isolated from 102±3 and 135±1dGA sheep (n=11/group). Cells were treated with T3 (0.37, 1.5nM), IGF‐1 (1ug/ml), NH3 (100nM) or a combination. Proliferation was quantified by BrdU uptake (10uM). Western blots measured ERK, AKT, TRa, and p21 expression. Results: IGF‐1 stimulated proliferation at both ages. T3 reduced this mitotic activity by ~50% in 100dGA and ~75% in 135dGA. At both ages T3 increased p21 (p<0.001), and NH3 blocked the T3+IGF‐1 reduction of BrdU uptake without altering ERK or AKT. In 100dGA CMs NH3 did not reduce T3‐induced p21 expression but upregulated TRa (p<0.05). In 135dGA CMs, NH3 alone reduced BrdU uptake as well as T3‐induced p21 (p<0.05). Conclusion: Fetal ovine CMs are sensitive to the effects of NH3 differently depending on maturation state. NH3 inhibition of proliferation suggests that TRs are needed for normal proliferation in the developing myocardium and that p21 may be the main effector. Grant Funding Source: Supported by NIH NHLBI and NICHD
Post‐burn alterations in cardiac Erk1/2 signaling (850.4)
Authors: Guillory Ashley , El Ayadi Amina , Herndon David , Finnerty Celeste 
Published: June 2021

Introduction. Severe burn trauma causes a catecholamine surge that has been demonstrated, in pediatric patients, to last up to 3 years post injury. The detrimental cardiac effects of the catecholamine surge include a reduction of functional β‐adrenergic receptors (β‐AR) and alterations in various signaling pathways such as that of extracellular signal regulated kinase (Erk1/2).Methods. We used a rat model of 60% total body surface area burn to investigate burn‐induced changes in cardiac signaling pathways. Animals were sacrificed and hearts were isolated 24 hrs and 7 days post injury. The expression and phosphorylation of proteins involved in Erk1/2 signaling were examined via Western Blot.Results. β1‐AR expression levels were significantly increased 24 hrs post‐burn (p=0.009) but returned to control levels by 7 days post‐burn. No changes were observed in β2‐AR expression levels. Gi expression was initially depressed post‐burn but was increased at 7 days post‐burn (p=0.0009). Similarly, Erk1/2 phosphorylation was increased by 7 days post‐burn (p=0.036). However, Akt phosphorylation was decreased at 7 days post‐burn (p=0.01).Conclusion. These data indicate that burn injury alters Erk1/2 activation and activity, which may promote pro‐hypertrophic and pro‐apoptotic signaling. Furthermore, in the long‐term, these changes may underlie burn induced cardiac dysfunction and subsequent mortality.Grant Funding Source: Supported by grants from the NIH (P50‐GM60338, KL2RR029875,UL1RR029876) and SHC (80100, 71001).
Hydrogen‐rich saline reducing cardiac toxicity induced by adriamycin in rats (850.6)
Authors: Liu Songqing , Liu Yunjia , Yu Pan , Sun Xuejun 
Published: June 2021

Background. Hydrogen, which could selectively reduce the hydroxyl radical, is considered to be a novel antioxidant. In this study, we examined the effectiveness of hydrogen rich saline solution on the prevention of cardiotoxicity induced by Adriamycin (ADR) in rats.Methods. 30 Male Sprague‐Dawley® rats were divided randomly into 3 groups. Physiologic saline , hydrogenrich Saline or nothing was administered through intraperitoneal (i.p.) injection after exposure to ADR (2.5 mg/kg/week for 6 weeks) respectively. The levels of IL‐1b, TNF‐αand 8‐OHdG in heart were quantified using enzymelinked immunosorbent assay (ELISA) kits specific for rat according to the manufacturers’ instructions (R&D systems).Results. The death rate of hydrogenrich Saline group is lower than others. Rats in the H2 group displayed a reduced degree of myocardial neutrophilic infiltrate, necrosis, hemorrhage, and spindle‐shaped interstitial cells as compared with rats in the Control group..The number of TUNEL‐positive cells were increased in the myocardium in the Physiologic saline group and Control group. H2 comparably decreased the frequency of TUNEL‐positive cells relative to the Control group. And the level of 8‐OHdG, IL‐1b and TNF‐a were decreased in the hydrogenrich Saline group.Conclusion. The results of this study demonstrate that hydrogen‐rich saline ameliorated cardiotoxicity induced by Adriamycin by reducing oxidative stress and inflammatory cascades in heart tissue.
Influence of araloside C on cardiac contractile function (850.7)
Authors: Wang Min , Xu Xudong , Sun Guibo , Sun Xiaobo 
Published: June 2021

The present study aimed to determine the direct effect of araloside C on Ca2+ transient and contractions in isolated rat cardiomyocytes. In isolated adult rat cardiomyocytes, contractile and intracellular Ca2+ properties were determined simultaneously in real time by using an IonOptix MyoCam system. Western blot analysis was performed to evaluate the expressions of Ca2+ cycling proteins, including sarcoplasmic reticulum calcium ATPase 2a (SERCA2a), phospholamban (PLB), and Na+‐Ca2+ exchanger (NCX). Our results showed that araloside C directly increased sarcomere shortening, maximal velocity of shortening/relengthening (±dL/dt) and amplitude of [Ca2+]i transients in a concentration‐dependent manner. SERCA activity was also increased by araloside C. The expression of SERCA2a was not significantly upregulated, whereas PLB and NCX expressions were downregulated. These findings revealed the positive inotropic effect of araloside C on isolated rat cardiomyocytes. This effect was possibly associated with an increase in amplitude of the [Ca2+]i transient.Grant Funding Source: This study was supported by the National Natural Sciences Foundation of China (Grant No. 81173589).
Activation on nNOS/H2O2 pathway by atorvastatin: implications in the relaxation and endothelial dysfunction induced by lysophosphatidylcholine (851.16)
Authors: Campos Mota Gianne , Navia‐Pelaez Juliana , Lemos Virgínia , Aggum Capettini Luciano 
Published: June 2021

Studies of vascular reactivity were performed using aorta thoracic rings of C57BL/6J male mice pre‐incubated with Lysophosphatidylcholine (LPC, 10 µM, 30 minutes). LPC induced endothelial dysfunction characterized by a reduction in acetylcholine response. However pre‐treatment with atorvastatin (Ator, 1 µM, 2h) restored the relaxation. In the presence of Nω‐nitro‐L‐arginine methyl ester (L‐NAME, 300 µM; non‐selective inhibitor of Nitric Oxide Synthase‐NOS) the effect on relaxation was totally bolished. Selective inhibition of nNOS with 1‐[2 ‐ (trifluoromethyl) phenyl] imidazole (TRIM, 300 µM) blocked the improvement of endothelial function induced by Ator. Catalase (2400U/ml, which degrades H2O2, a product of nNOS), also abolished the protective effect of Ator. These results suggest that endotelial dysfunction induced by LPC was reverted by the increase of nNOS activity mediated by Ator. NO and superoxide anion (O2‐) production were measured in human endothelial cells by Flow Cytometry using the robes DAF‐FM and DHE, respectively. LPC induced an increase on O2‐ and a decrease in NO production. Ator induced an increase in NO and abolished the O2‐ production by LPC. The effects of Ator in the production of NO and O2‐ was abolished by TRIM. The results suggest that Ator presented a vascular protection mediated by nNOS activation and production of NO and H2O2, improving endotelial function.Grant Funding Source: FAPEMIG, CAPES, CNPq.
Evaluation of Atorvastatin effect on oxLDL induced inflammatory response and oxidative stress in human endothelial cells: a role for nNOS (851.17)
Authors: Navia Pelaez Juliana , Costa Aguilar Edenil , Diniz Thiago , Alvarez‐Leite Jacqueline , Lemos Virginia , Capettini Luciano 
Published: June 2021

Human endothelial cells incubation with oxidized LDL (oxLDL; 6 and 24 h) increased reactive oxygen species (ROS) and NO production associated to an increase in iNOS and eNOS expression. eNOS activation was compromised at 6h but increased after 24h, suggesting eNOS uncoupling. nNOS expression and activity as well as SOD2 expression were reduced and catalase showed increased expression after 6 and 24h. Atorvastatin (Ator; 1uM) reduced oxidative stress by restoring NOS, SOD2 and catalase expression associated to superoxide and NO reduction levels. Ator reduced catalase and increased SOD2 expression. This treatment showed increase eNOS activation and nNOS expression up to control levels in the first 6 h, while its inactivation was reduced after 6 and 24 h. iNOS expression was reduced by atorvastatin treatment indicating NO unbalance regulation and possible anti‐inflammatory effect. oxLDL incubation increased pro‐inflammatory cytokines TNF‐α, IL‐6, CCL‐2 and IL‐1β production and reduced anti‐inflammatory cytokines TGF‐β and IL‐10. Ator reduced production of pro‐inflammatory cytokines (except TNF‐ α) and increased anti‐inflammatory cytokines. These effects could be related to a reduction in oxLDL uptake by endothelial cells during atorvastatin co‐incubation. In addition, nNOS inhibition increased oxLDL uptake after 6 and 24 h. These Results suggest nNOS involvement in atorvastatin protective effects.Grant Funding Source: CAPES, FAPEMIG, CNPq
Tetrahydrobiopterin lowers muscle sympathetic nerve activity in patients with chronic kidney disease (852.8)
Authors: Park Jeanie , Sher Salman , Jefferson Melanie , Quyyumi Arshed 
Published: June 2021

Chronic kidney disease (CKD) is characterized by chronic overactivation of the sympathetic nervous system (SNS) that contributes to increased blood pressure and cardiovascular risk. One contributing factor to SNS overactivation in this population is decreased nitric oxide (NO) bioavailability. Tetrahydrobiopterin (BH4) is a necessary cofactor for endothelial nitric oxide synthase (eNOS) that has been shown to increase NO bioavailability in experimental models of CKD. We conducted a randomized, double‐masked, placebo‐controlled trial testing the potential benefits of oral BH4 treatment on SNS activity in CKD patients. 36 patients with CKD and hypertension were randomized to 12 weeks of: 1) 200mg BH4 twice daily + 1mg folic acid once daily; versus 2) matching placebo twice daily + 1mg folic acid once daily. The primary endpoint was change in muscle sympathetic nerve activity (MSNA) assessed via microneurography. Secondary endpoints included ambulatory and clinic blood pressures, endothelial function via brachial artery flow‐mediated dilatation, oxidative stress biomarkers, and proteinuria. We observed a significant reduction in MSNA after 12 weeks of BH4 treatment, compared to treatment with placebo, in hypertensive CKD patients. Chronic BH4 treatment may have beneficial effects on central sympathetic output in hypertensive patients with CKD.Grant Funding Source: Supported by K grant HL098744
Enhanced chemoreflex gain in obstructive sleep apnea predicts systolic blood pressure response to voluntary apnea (852.9)
Authors: Jouett Noah , Watenpaugh Don , Smith Michael 
Published: June 2021

Background: Obstructive Sleep Apnea (OSA) imposes significant cardiovascular risk, independent of frequently co‐morbid obesity and metabolic syndrome. Much of the increased cardiometabolic risk due to OSA is imparted through exaggerated activation of the sympathetic nervous system (SNA). We hypothesized that enhanced pressor responses to voluntary apnea in OSA are associated with increased chemoreflex gain.Methods: It has been established that systolic blood pressure (SBP) response to apnea is an indicator of SNA. We enrolled 9 subjects with untreated OSA and 10 healthy subjects in a laboratory‐based study. Subjects were randomly exposed to varying concentrations of hypoxic gas (21%, 16% and 12%) while assessing SBP and MSNA responses. In a clinical setting, 20 subjects with untreated OSA and 24 control subjects performed three 20 second apneas while measuring SBP response.Results: OSA subjects had greater systolic and mean BP responses to voluntary apneas compared to control at all levels of pre‐apnea hypoxia (P<0.05). Further, OSA subjects at all levels of hypoxia experienced greater ΔMSNA/ΔSaO2 responses compared to control (P<0.001), and chemoreflex gain (as ΔMSNA/ΔSaO2) was strongly predictive of the SBP responses to apnea (R=.808, P<0.001).Conclusions: These results support the hypothesis that chemoreflex gain predicts SBP responses to voluntary apnea observed in patients with OSA.
Role of sympathetic innervation on cerebral artery remodeling during chronic hypoxia in fetal lambs (853.3)
Authors: Adeoye Olayemi , Silpanisong Jinjutha , Williams James , Kim Dahlim , Pearce William 
Published: June 2021

Cerebral arteries adapt to chronic hypoxia by altering the phenotypes of the plastic and heterogeneous population of cells in the artery wall. Perivascular nerves also undergo differentiation during hypoxia and alter vasotrophic effects on arteries. Here we test the hypothesis that nerves from the superior cervical ganglia (SCG) mediate hypoxic remodeling of ovine cerebral arteries. Using a chronic hypoxia (CH) and unilateral sympathectomy (SANX) model, we tested effects of CH and SANX on tone, contractile proteins and cell proliferation. Contractile responses to electrical nerve stimulation were upregulated (794%) by CH. CH ↑ dopa beta hydroxylase by 360% and SANX ablated this. CH↓ colocalization of a synthetic isoform of myosin heavy chain (SMemb) with smooth muscle alpha actin (AA) by 69%. SANX ↑ the colocalization by 600% in hypoxic arteries. NE in culture ↓ the colocalization by 91% and co‐culture of NE with prazosin ↑ it by 1363%. Also CH ↓ area per cell by 9% (media) and 45% (adventitia) whereas SANX ↑ it by 42% and 89% respectively. Also, CH ↓ colocalization of Ki67 (marker for cell proliferation) with AA by 15% (media) and 69% (adventitia). Together, these results suggest that the sympathetic cerebrovascular innervation helps mediate hypoxic remodeling through potentiation of NE synthesis, increased stimulation of α‐1 adrenoceptors, and transformation toward a contractile smooth muscle phenotype.Grant Funding Source: Supported by NIH Grants HD‐31266 and NS‐076945
Cerebral arterial wall remodeling following subarachnoid hemorrhage (853.5)
Authors: Lachkar Nadia , Guvenc Tuna Bilge , Bakker Erik , de Vos Judith , VanBavel Ed 
Published: June 2021

Delayed cerebral ischemia (DCI) is a serious complication after aneurysmal subarachnoid hemorrhage (SAH). A significant cause of DCI is vasospasm of the major cerebral arteries. We hypothesized that vasospasm is not simply vasoconstriction but an ongoing process of remodeling of the vascular wall, and tissue transglutaminase 2 (TG2) may be involved in the remodeling of cerebral arteries after SAH.The exposure to subarachnoid blood was mimicked in an in vitro wire myograph study on rat middle cerebral arteries (MCA) and basilar arteries. Smooth muscle cell (SMC) contractile plasticity and matrix remodeling were assessed from changes in wall tension during full activation and total relaxation. 16 hours of incubation with blood caused contractile activation of SMCs, and induced luminal narrowing and inward matrix remodeling of both the MCA and basilar artery. Incubation with TG2 inhibitor L682.777 countered the effect of blood induced remodeling. In an in vivo prechiasmatic injection model for SAH performed in mice (2 days) and rats (3 days), we found no SMC plasticity and no vascular wall remodeling, despite early changes in cerebral blood flow.Our in vitro data suggest that exposure of the cerebral arteries with blood results in vascular wall remodeling and luminal narrowing in a TG2‐dependent manner. However, in the in vivo SAH models such changes were not observed.Grant Funding Source: Supported by SMART FP7 Marie Curie ITN number 235711