bluuebunny/crossref_metadata_2025 huggingface dataset:
PI3 Kinase/Akt Signaling Pathway Mediates Alcohol‐Induced Cardiomyopathy
Authors: Cousins Valerie M. , Alvin Zikiar , Zhao Aiqiu , Haddad Georges E.
Published: June 2021

Alcohol has negative effects on cardiac function. The mechanisms of alcohol‐induced cardiomyopathy are still unknown. We showed that the PI3 Kinase pathway affects the contractility of cardiac cells via ion channels. The aim is to find the relationship between PI3 Kinase/Akt pathway and alcoholic effect on cardiomyocyte contractility. Sarcomeric and cellular contractility parameters were measured in the presence of high (HA: 100mM) or moderate (MA: 20mM) levels of alcohol (1h) in freshly isolated adult rat cardiomyocytes (Ionoptix, MA). Alcohol reduced Ca2+ influx (39%) and decreased Ca2+ sequestration time constant (τ) by 31%. However, the velocity of Ca2+ influx was enhanced by MA (42%), while HA seemed to decrease it (21%). This was corroborated with lower cellular (21%) and sarcomeric (20%) contractility in the presence of alcohol which was abrogated by LY294002 or Ad.Akt179M transfection. The velocity of contraction was decreased by HA (26%), which was negated by transfection of cardiomyocytes with Ad.Akt179M. The τ was enhanced by HA (50%), but reduced by MA (25%). The former was inhibited by Ad.Akt179M but not the latter. At the sarcomere level, HA reduced sarcomeric τ (33%) with no effect on the sarcomere length. Thus, alcohol induced reduction in contractility and increase in the relaxation time may be mediated by the PI3 Kinase/Akt. Support: grants GM08016‐38 from NIH/NIGMS and 2G12 RR003048 RCMI.
Modeling Regulation of Mitochondrial Free Ca2+ by Extra‐mitochondrial Mg2+ during ADP Phosphorylation
Authors: Dash Ranjan K , Pradhan Ranjan K , Agarwal Bhawana , Boelens Age D , Haumann Johan , Camara Amadou KS , Stowe David F
Published: June 2021

Mitochondrial free Ca2+ ([Ca2+]m) is regulated by Ca2+ influx via Ca2+ uniporter and Ca2+ efflux via Na+/Ca2+ exchanger as well as by Ca2+ buffering via mitochondrial metabolites and proteins. However, [Ca2+]m regulation during transient state‐3 respiration is not well understood. To test competing hypotheses and gain a quantitative understanding of [Ca2+]m regulation, we developed a detailed computational model by integrating our recent biophysical models of cation transporters into our existing model of mitochondrial bioenergetics. The model also accounts for binding and buffering of cations with proteins and metabolites, including ATP, ADP and Pi. Experiments were conducted to measure [Ca2+]m, [Ca2+]e, ΔΨm, [NADH]m, and matrix volume in guinea pig heart mitochondria suspended in Na+, Mg2+, and Ca2+ free buffer (1 mM EGTA) respiring with 0.5 mM pyruvic acid. Dynamics were inferred by adding CaCl2 (0.25, 0.5, 0.65, 0.75, 0.85, 1.0 mM) followed by 250 μM ADP with or without 25 μM RuR, 1 mM MgCl2, and ANT and F1F0‐ATPase blockers. Model analyses of the data suggest (a) [Ca2+]m is regulated by Ca2+ phosphate precipitation, (b) [Ca2+]m is a feedback inhibitor and [Mg2+]e is a competitive inhibitor of Ca2+ influx, (c) matrix [ADP] may activate Ca2+ influx during ADP phosphorylation, and (d) ATP synthesis leads to matrix contraction and contributes to the transient increases in [Ca2+]m during state‐3 respiration.
META060 from hops reduces weight gain, increases weight loss, improves fasting glucose and insulin sensitivity in high‐fat fed mice
Authors: Konda Veera R , Vroegrijk Irene , van Diepen Janna A , Darland Gary , Desai Anuradha , Babish John G , Tripp Matthew L , Bland Jeffrey S , Voshol Peter J
Published: June 2021

Obesity is a complex disease resulting from a prolonged positive imbalance between energy intake and energy expenditure with excess fat accumulating in various organs and tissues. META060, a defined hop extract, was analyzed in various cell models of obesity/type‐2 diabetes. META060 stimulated the secretion of GLP‐1 in intestinal L cells (NCI‐H716); stimulated the production of adiponectin in adipocytes (3T3‐L1); activated the phosphorylation of AMPK levels in muscle cells (C2C12); and inhibited nitric oxide levels in both myocytes and macrophages (RAW264.7). META060 was evaluated in a mouse model of high fat diet (HFD) induced obesity. Mice supplemented for 14 weeks with META060 (100 mg/kg body weight) prevented the HFD induced weight gain, and the rate of weight gain was similar to that of the low fat diet group. META060 significantly reduced HFD induced fat accumulation in viscera, subcutaneous tissues and gonads, and exhibited a significant reduction in fasting glucose and insulin. In addition, mice switching to HFD+META060 after 14 weeks of HFD dramatically increased the weight loss within 2 weeks. In oral glucose tolerance test, addition of META060 to HFD for 14 weeks reduced insulin levels. In conclusion, META060 reduced weight gain, fasting plasma insulin and glucose levels, and improved insulin sensitivity in mice fed with high fat diet. Supported by MetaProteomics, LLC.
NF‐κB activation and oxidative stress in the paraventricular nucleus contribute to sympathoexcitation via interaction with neurotransmitters in heart failure
Authors: Kang Yu‐Ming , Sun Yao‐Jun , Qin Da‐Nian , Yang Li‐Min , Ren Xiao‐Xia , Zhou Yun , Cao Xi‐Mei , Xu Yan‐Yan , Francis Joseph
Published: June 2021

Nuclear factor kappa B (NF‐κB) is a potent inducer of proinflammatory cytokines (PIC) and oxidative stress in cardiovascular disease. In this study, we determined whether NF‐κB activation and oxidative stress in the paraventricular nucleus (PVN) contribute to sympathoexcitation via interaction with neurotransmitters in the PVN in heart failure (HF). Rats with HF induced by coronary ligation and sham‐operated controls (SHAM) were treated for 4 weeks with bilateral PVN infusion of NF‐κB inhibitor SN50, or the superoxide scavenger tempol, or vehicle. Compared with SHAM rats, HF rats had higher levels of norepinephrine (NE) and glutamate and lower levels of gamma‐aminobutyric acid (GABA) in the PVN, along with high levels of Fra‐LI (an indicator of chronic neuronal activation), PIC, superoxide, gp91phox (a subunit of NAD(P)H oxidase), phosphorylated IKKβ (p‐IKKβ) in the PVN, and increased renal sympathetic nerve activity (RSNA). HF rats had higher plasma levels of NE, epinephrine (EPI), angiotensin II and PIC. Treatment with bilateral infusion of SN50 or tempol attenuated these HF‐induced changes. These findings suggest that NF‐κB activation and oxidative stress in the PVN modulate neurotransmitters and contribute to sympathoexcitation in rats with ischemia‐induced HF.
Nucleus Raphe Pallidus in EA inhibition of rostral ventrolateral medulla and cardiovascular excitatory responses
Authors: Li Peng , Tjen‐A‐Looi Stephanie C. , Longhurst John C.
Published: June 2021

EA at P5‐6 acupoints (median nerve) excites the arcuate nucleus and ventrolateral periaqueductal gray (vlPAG), and inhibits sympathetic cardiovascular rostral ventrolateral medulla (rVLM) neurons and associated reflex responses. The present study investigated the role of the NRP in EA inhibition of rVLM neurons and whether EA and activity from the vlPAG to the rVLM passes through the NRP. In [alpha]‐chloralose anesthetized cats the splanchnic nerve (SN) was stimulated to induce cardiovascular sympathoexcitatory reflexes and EA was applied at P 5‐6 acupoints. A recording electrode was inserted into the NRP or rVLM. Microinjection of dl‐homocysteic acid (DLH), but not normal saline (NS), into vlPAG increased the NRP neuronal response to SN stimulation (5±1 to 12±1 spikes/30 stim). EA at P 5‐6 for 30 min increased the NRP response to SN stimulation (5±1 to 14±3 spikes/30 stim). EA excitation of the NRP response was blocked by microinjection of kynurenic acid (KYN) into the caudal vlPAG. Furthermore, the reflex increase in BP induced by application of bradykinin on gallbladder and the rVLM neuronal response to SN stimulation was inhibited (~58%) by injection of DLH into the vlPAG, a response that could be blocked by injection of KYN into the NRP. Thus, EA activates the arcuate and vlPAG, which excites the NRP and, in turn, inhibits the rVLM activity and sympathoexcitatory cardiovascular reflex responses. (HL‐63313)
The role of AT1A receptors in autonomic adjustments to natural behaviors in mice: influence of background context
Authors: Mayorov Dmitry , Chavez Carolina A , Choy Kwok H , Yu Jing , Hawkes David J
Published: June 2021

Angiotensin AT1 receptors are implicated in regulating blood pressure (BP) reactivity to acute aversive stress. In this study, we examined the influence of AT1A receptor deficiency on natural behaviors and associated BP adjustments in mice in a low‐stress environment (home cages in the animal house) and in an unfamiliar background context (home cages relocated to the laboratory). The relocation had a limited effect on natural behaviors in AT1A+/+ mice, including exploring, grooming, nesting and eating. Their activities remained clustered together and separated by longer rest periods. Conversely, the ultradian behavioral pattern was disrupted by the relocation in AT1A−/−mice, with resting bouts frequently interrupted by brief, single‐type activities. The activity‐associated BP changes were similar in both strains (+20 to +30 mmHg) in either context, and were abolished by α1‐adrenergic blockade with prazosin. Unexpectedly, the BP response to an aversive stimulus (shaking cage for 5 min at 80 rpm) was blocked by prazosin only in ‘home‐based’ (+4±2 mmHg), but not in ‘relocated’ AT1A−/−mice (+22±3 mmHg). These data suggest that, under low‐stress conditions, AT1A receptors play little role in regulating BP responses to natural behaviors in mice. However, they may be important for effective adaptation, at both behavioral and physiological levels, to a potentially aversive background context. NHMRC (Australia)
Human brain activation associated with cough and cough suppression
Authors: Mazzone Stuart , Cole Leonie , Ando Ayaka , Farrell Michael
Published: June 2021

Supramedullary brain regions may contribute to control of cough by facilitating or inhibiting brainstem reflex pathways. Using functional brain imaging, we put this putative model to the test. Blood oxygen level‐dependent (BOLD) contrast images were acquired from 15 healthy subjects after inhaling saline, inhaling capsaicin without cough, inhaling capsaicin with cough, and voluntary cough after inhaling saline. BOLD signals were analysed to identify changes associated with cough, capsaicin stimulation and their interactions. Contrary to the hypothesised effect, the positive interaction of cough and capsaicin stimulation did not implicate brain activation uniquely associated with evoked cough. However, the negative interaction revealed brain activations that may be requisite for the initiation of voluntary cough and suppression of evoked cough (inferior frontal gyrus, SMA, cingulate cortex) as well as ongoing sensations associated with capsaicin in the airways (insula, orbitofrontal cortex)(P<0.05). These data show that voluntary cough and suppression of evoked cough are associated with brain activation in excess of that associated with evoked cough. This outcome suggests that evoked cough is a default motor pattern that does not require active facilitation by higher order centres, but is under higher order inhibitory influences.

Funding: NHMRC Australia #454776, #566734
Dopaminochrome induces neuroinflammation in the substantia nigra of Sprague Dawley rats
Authors: Breckenridge Julie Marie , Zahm Daniel S , Westfall Thomas C , Macarthur Heather
Published: June 2021

Our lab has observed that dopaminochrome (DAC), an oxidized form of dopamine, is cytotoxic to the mesencephalic cell line MN9D and induces an inflammatory response in the microglial cell line BV2. Dopamine is highly susceptible to oxidation and may form DAC when exposed to an oxidizing environment, leading to polymerization of DAC into neuromelanin, of which DAC is a major component. We believe the formation of DAC and its subsequent aggregation to neuromelanin may play a role in the progression of Parkinson's disease due to its proinflammatory and cytotoxic properties. In this study, we examined the effect of DAC in vivo. DAC (10 nmoles) was stereotaxically injected into the substantia nigra pars compacta (SNpc) of Sprague Dawley rats. Five, ten, and twenty days post‐surgery, the brains were harvested and assessed for inflammation and neurodegeneration. Results to date suggest that acute administration of 10 nmoles DAC is sufficient to induce activation of SNpc resident microglia without any apparent neurodegeneration. The profile of the resulting inflammation and the effect of microglial inhibition prior to DAC injection will be further assessed. (Supported in part by NIGMS 008306)
Lactate metabolism in the jumping muscle of the American locust (Schistocerca americana)
Authors: Swift Mary Catherine , Kirkton Scott D
Published: June 2021

Many species use anaerobic respiration to meet energy demands during burst locomotion; yet, metabolites of this process, such as lactic acid, have been linked to muscular fatigue and must be removed following exercise. The removal of lactic acid varies considerably between mammals, reptiles and fish. Although insects do not normally produce lactic acid to meet locomotory demands, the American locust (Schistocerca americana) uses anaerobic respiration during jumping. To induce anaerobic respiration, we forced grasshoppers to jump for three minutes at 35°C. The animals were then allowed to rest for 0 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour, 3 hours, or 24 hours to determine how long the lactic acid remains in the femur. After resting, grasshoppers were frozen in liquid nitrogen and the femurs were homogenized for use in a fluorometric lactate assay. After three minutes of jumping, the lactate concentration in the femoral muscle was 11.0 mmol·kg−1. Lactate levels dropped by 50% following 15 minutes of post‐exercise rest. Additionally, lactate levels decreased 2.5‐fold further after 30 minutes of rest and were unchanged 24 hours after exercise. It is not yet clear if the lactic acid is being processed by the muscle or is being transported in the hemolymph from the femur to the abdomen. Future research will address lactate concentrations in the hemolymph following exercise.
The analysis of avian plasma for glycated serum albumin
Authors: Anthony Claire Marie , Sweazea Karen L , Braun Eldon J
Published: June 2021

Plasma glucose concentrations (Pglu) in humans are regulated at 80–100mg%. If levels reach 150mg% for 4–6 weeks, the symptoms of Type 2 diabetes appear due to the glycation of serum albumin and the subsequent formation of advanced glycation end‐products (AGEs). AGEs bind to vascular tissues leading to the pathologies associated with Type 2 diabetes. In contrast to humans, the Pglu of birds range from 350–750mg% and from what is observed, birds do not suffer the pathologies of Type 2 diabetes. To gain an understanding of this discrepancy, in vitro experiments were conducted to analyze the reaction between glucose and avian serum albumin (ASA) and bovine serum albumin (BSA) which was used as a control. Glycated ASA and BSA were separated using boronate affinity columns and percent glycation was quantified using the Bradford protein assay. Results indicate that ASA is glycated to a lesser degree than BSA when exposed to varying concentrations of glucose. After 16 weeks of in vitro incubation with 500mM glucose, 37.8 ± 0.76% of BSA was glycated compared to 19.7 ± 1.06% for CSA, a highly significant difference (P<0.05). Additionally, glycation appeared to be glucose dependent, where the percent glycation at week 16 was significantly higher than the control solutions for both BSA (P<0.001) and CSA (P<0.05, P<0.001 and P<0.001 respectively for the glucose concentrations of 38.8mM, 100mM and 500mM).
Activation of survival and apoptotic signaling pathways in lymphocytes exposed to palmitic acid
Authors: Takahashi Hilton Kenji , Cambiaghi Tavane David , Luchessi Augusto Ducati , Newsholme Phillip , Curi Rui
Published: June 2021

Lymphocytes use both glucose and glutamine as metabolic fuels at high rates even when they are immunological quiescent. T‐Lymphocytes in their basal state express low levels of Insulin Receptor (IR) and Glucose Transporter‐4 (GLUT‐4), and cellular glucose uptake is mediated by GLUT‐1. Fatty acids are known to play diverse roles for immune cell function acting as a source of carbon for oxidation and as structural components of cell membrane phospholipids. However, there is increasing evidence that free fatty acids can cause cell death through activation of apoptosis. Palmitic Acid (PA) induced apoptosis of Jurkat cells in a dose‐dependent manner as indicated by DNA fragmentation, mitochondrial membrane depolarization, cytochrome c release and activation of caspases 3/9 and JNK, p38 and ERK proteins. Concomitantly, PA treated‐Jurkat cells exhibited an increase of IR and GLUT‐4 content in their plasma membrane in the absence of insulin. PA treatment increased glucose uptake but diminished its conversion to CO2, and raised the content of the major lipid classes: triglyceride, cholesterol ester, free fatty acid and phospholipids. We suggest that, in an attempt to survive, lymphocytes activate insulin signaling pathways and glucose utilization in response to PA so stimulating the synthesis of lipid macromolecules therefore removing PA from mediating intracellular cytotoxic effects.
Inhibition of β‐catenin/cyclic AMP Response Element‐binding Protein‐binding Protein Interaction by ICG‐001 Improves Contractile Function in Chronically Infarcted Rat Myocardium
Authors: Hwang Hyosook , Sasaki Tomoyo , Kahn Michael , Kloner Robert A.
Published: June 2021

The adult heart has limited ability to repair after injury. Developing strategies that improve post‐infarct repair are needed. Wnt/β‐catenin signaling has been implicated in cardiac regeneration. We demonstrate that selective inhibition of the interaction between coactivator cyclic AMP response element‐binding protein‐binding protein, CBP and β‐catenin by a small molecule inhibitor ICG‐001 (ICG) benefits the infarcted myocardium. Rats undergoing coronary ligation received either ICG or pbs for 10 days. The left ventricular contractile function, infarct size, and remodeling were determined 4 weeks. ICG treatment significantly improved ejection fraction by 20%, compared to pbs. The increase in ejection fraction occurred without beneficial effects on infarct size, ventricular cavity volume, and infarcted wall thickness. To investigate the potential mechanism, proliferation and expressions of regenerative genes were studied at 7 days. BrdU positive cells, including myocytes, were observed in the epicardium of the infarcted wall in both groups. mRNA levels of c‐kit, Sca‐1, GATA‐4, and myosin were similar in both groups. Our data show that selective inhibition of β‐catenin/CBP interaction improves contractile function in the infarcted heart. We speculate that the effect of ICG is not in the proliferative phase; the exact mechanism whereby ICG‐001 has its positive effect remains to be determined.
Low‐level laser combined with transplantation of mesenchymal stem cells promote functional recovery of sciatic nerve crush injury in a rat model
Authors: Hsieh Yueh‐Ling , Yang Chen‐Chia , Ou Hsiu‐Chung
Published: June 2021

Present study examined whether low‐level laser (LL) in combination with transplantation of mesenchymal stem cells (MSC) have synergistic effects leading to functional recovery that is greater than MSC therapy alone. Adult male SD rats received sciatic nerve crush injury by the vessel clamp for 20‐minute were divided into three groups: denervated + MSC transplant + LL (group I), denervated + MSC transplant (group II) and denervated (group III). MSC isolated from rat bone marrow was injected into the lesion site in group I and II and culture medium for group III. Three days after surgery, group I received GaAlAs LL irradiation (660nm, 9 J/cm2) for 7 days. Functional assessments including sciatic function index (SFI), vertical activity (VA), angle of ankle (AA), and electrophysiological studies were performed. Histological analysis was made to assess nerve continuity and myelination. Significant differences in SFI, VA, AA, amplitudes and onset latencies of compound muscle action potentials were found between group I and II. Decreased vacuole formation and axon degeneration examined by haematoxylin and eosin staining was found in group I. Results showed that the MSC/LL‐combined treatment had the most beneficial effect which may involve the attenuation of inflammatory responses by LL. This study was supported by a grant from the National Science Council (NSC 96‐2314‐B‐241‐001‐MY3) of Taiwan.
Characterization of novel kidney specific manganese superoxide dismutase knockout mice
Authors: Parajuli Nirmala , Saba Hamida , Mitchell Tanecia , MacMillan‐Crow Lee Ann
Published: June 2021

Inactivation of manganese superoxide dismutase (MnSOD), the major mitochondrial antioxidant, is a key issue in renal failure following transplantation or ischemia/reperfusion (IR) injury. Homozygous MnSOD knock out (KO) mice die shortly after birth, and heterozygous MnSOD KO mice have decreased MnSOD activity in all tissues/organs. To address the role MnSOD inactivation has on renal injury, we generated bi‐transgenic kidney specific MnSOD KO (50% and 100%) mice by breeding KidneyCre mice1 and floxed MnSOD mice2. Characterization of these KOs revealed that phenotypically the mice are smaller in size compared to littermate controls, but show no survival differences. Immunohistochemistry data showed that the Cre‐recombinase mediated MnSOD deletion occurred specifically in the kidney and was located predominantly in the medullary region. The kidney specific KOs exhibited histologic evidence of mild renal damage, increased tyrosine nitration, and renal cell death. KO mice renal function was not altered; however, more renal damage was observed following IR injury compared to littermate controls. In summary, we have developed a novel kidney specific MnSOD KO mouse model that will help define the molecular pathways that occur downstream of MnSOD inactivation during renal injury.

Supported by NIH grant 1RO1DK0789361.
Effects of chronic antioxidant treatment on AT‐1 receptor, NAD(P)H oxidase subunits and main antioxidant enzymes gene expression in the kidneys of 2K‐1C rats
Authors: Nishi Erika Emy , Oliveira‐Sales Elizabeth B , Bergamaschi Cassia T , Oliveira Thais G. C. , Boim Mirian A , Campos Ruy R
Published: June 2021

Previous studies showed that chronic treatment with an antioxidant: vitamin C (vC) improves hypertension and sympathetic vasomotor hyperactivity in an Ang II‐dependent model of renovascular arterial hypertension. To test the hypothesis that oxidative stress is associated with NAD(P)H oxidase activation by Ang II, gene expressions of AT‐1 receptor (AT1R), NAD(P)H oxidase subunits (p47phox and gp91phox) and main antioxidant enzymes were evaluated in the renal cortex of 2 kidney‐1 clip model (2K1C, 6 weeks after clipping) rats before and after vC (150mg/kg/day). Gene expression of AT1R was elevated (51%) in the clipped kidney (CK) and reduced (47%) in the nonclipped kidney (NK) of 2K1C group. vC reduced AT1R expression only in the CK (31%). Elevated gene expression of p47phox and gp91phox was observed only in the CK of 2K‐1C group (184% and 132%, respectively) and vC produced no changes in these expressions. Gene expression of catalase was reduced in the CK (70%) and NK (83%) of 2K1C rats. vC increased gene expression of glutathione peroxidase (GPx) in the CK (185%) and NK (212%) of 2K1C. The present study suggests that renal oxidative stress may be related to elevated AT1R and NAD(P)H oxidase subunits gene expression in the CK of 2K1C rats and vitC treatment may produce beneficial effects by AT1R downregulation in the CK and increase in GPx gene expression in the kidneys of 2K1C rats.

Supported by FAPESP (07/56925‐1)
High Salt Diet –Induced Afferent Arteriolar Autoregulatory Dysfunction is Improved by Acute Antioxidant Treatment
Authors: Inscho Edward W. , Pollock David M. , Pollock Jennifer S. , Cook Anthony K.
Published: June 2021

High salt (HS) diet reduces myogenic reactivity in resistance arteries and autoregulatory responses of afferent arterioles. Oxidative stress is increased in HS rats. We tested the hypothesis that HS blunts autoregulatory behavior by stimulating accumulation of reactive oxygen species. Rats were fed a normal (NS, 0.4% NaCl) or HS (8% NaCl) diet for a period of 14 days. Baseline arteriolar diameter was similar between the NS and HS groups. Autoregulatory behavior was assessed by measuring diameter changes during step‐wise 15 mmHg increases in perfusion pressure from 65 to 170 mmHg. In NS kidneys, afferent arteriolar diameter decreased by 34 ± 2% (n=6) as perfusion pressure increased from 65 to 170 mmHg. In HS kidneys arteriolar diameter decreased by 6 ± 4% (P < 0.05; n = 8) indicating markedly attenuated pressure induced vasoconstriction. Acute exposure to Tempol (1.0 mM) in the superfusate had no effect on the autoregulatory response in NS rats but markedly improved autoregulation in the HS group. Increasing perfusion pressure from 65 to 170 mmHg in NS kidneys decreased afferent diameter by 32 ± 3% (n=3), whereas diameter decreased by 28 ± 3% (n=6) in kidneys from HS rats exposed to Tempol. These data indicate that reactive oxygen species blunt autoregulatory efficiency in kidneys from HS rats facilitating enhanced excretion of salt by buffering autoregulatory control of glomerular hemodynamics.
RyR function in sheep pulmonary arteries is differentially influenced by postnatal maturation and chronic hypoxia
Authors: Blood Quintin , Le Peterson , Papamatheakis Demosthenes G. , Longo Lawrence D. , Wilson Sean M.
Published: June 2021

Ryanodine receptors (RYR) and associated Ca2+ spark events are important to pulmonary arterial (PA) tone with potential differences in their role in fetuses as compared to adults. RyRs are implicated in hypoxic pulmonary vasoconstriction (HPV) and ET‐1 dependent contractility. Evidence also indicates HPV and PA tone are dysregulated by chronic hypoxia (CH) in fetuses and adults, and yet their combined influence on Ca2+ sparks and the relationship to PA tone is not known. We therefore tested the hypotheses that Ca2+ sparks are restricted before birth and that CH augments their function. These hypotheses were tested on PA from near term fetal sheep or adult ewes at low altitude or following 100+ days at 3801 m (CH). Ca2+ sparks were measured in fluo‐4 loaded PA strips while myography was performed on isolated PA rings. Ca2+ spark activity was far greater in adults relative to fetuses while CH accentuated spark activity in both groups. Selective RyR1 inhibition with 10 μM dantrolene (DAN) reduced spark activity in normoxic and CH fetuses and in normoxic but not CH adults, where 10 μM ryanodine (RY) restricted spark activity. Interestingly, DAN but not RY moderately reduced serotonin (5‐HT) mediated PA contraction in CH fetuses and adults. Overall, RyR function appears developmentally regulated and augmented by CH, and RyR function has modest influence on 5‐HT dependent contractility. NIH P01HD031226, R01HD003807 (LDL)
Muscarinic acetylcholine receptor dependent pulmonary arterial contractility is reduced by chronic hypoxia in fetal sheep
Authors: Nguyen Dan , Papamatheakis Demosthenes G. , Merritt Travis , Longo Lawrence D. , Wilson Sean M.
Published: June 2021

Muscarinic acetylcholine (ACh) receptor (mAChR) activation relaxes arteries through endothelium‐dependent NO signaling pathways and endothelium removal from most systemic arteries alleviates ACh mediated relaxation. However, Ach induces “paradoxical” contractility in endothelium disrupted pulmonary arteries (PA) through mAChR activation, such as may occur with chronic hypoxia (CH). Given the intimacy between endothelial and myocyte function, and the potential for CH altering PA vasodilation, we tested the hypothesis that CH also reduces mAChR‐dependent PA contractility. This hypothesis was tested on endothelium‐denuded PA rings from near term fetal or adult sheep at low altitude or following 100+ days at 3801 m (CH). Ach or carbachol (10–100 μM) contracted PAs and CH reduced contractility in fetuses. In PA from CH adults, dose‐dependent carbachol elicited contractions were inhibited with the non‐selective mAChR antagonist atropine, and by selective inhibition of M2 mAChRs with 1 μM AF‐DX 116 or M3 mAChRs with 0.1 μM Dau 5884 or 4‐DAMP, but not M1 mAChRs with 0.1 μM pirenzipine. The studies suggest M3 and possibly M2 mAChR are important to ACh‐mediated PA contractility, and that CH reduces this contractility in fetuses. Presumably, mAChR activity helps match ventilation to perfusion and in CH fetus the loss of mAChR‐related contractility may help preserve this function. NIH P01HD031226, R01HD003807 (LDL)
Short Stay Track Ventilator Weaning in CVICU
Authors: Kistler Daniel T , Loik Paul , Geltz Amy , Mowry Jole , Clark Courtney , Dean Pat , Hartman Laurie , Vandewater Jennifer , MacDonald Jennifer , Giudici Maria , Rosenberg Andrew , Prager Richard
Published: June 2021

Cardiac surgery patients ICU length of stay(LOS) had increased since moving to a larger, 24 bed unit in the Cardiovascular building. This resulted in a reduction from 45% to 26% of patients being weaned post‐op in a 6 hour period. Longer delays in weaning post cardiac surgery patients off the ventilator, particularly routine Cardiac bypass and valve replacement/repair patients was found to increase overall LOS and a reduced ability to perform more surgeries. After collecting data indentifying the sources of these delays, we set out to reduce the time these patients were vented. Nursing staff and Respiratory therapists developed protocols and guidelines and then educated and trained staff to initiate these protocols with a 6 hour goal for each patient. Using these education tools and this new RT/RN extubation protocol we have been able to reduce ventilator time to pre‐CVC levels, opening more beds and availabilty to perform more surgeries.
A comparison of the MIGET and a simple model of pulmonary gas exchange
Authors: Rees Stephen Edward , Kjærgaard Søren , Andreassen Steen , Hedenstierna Göran
Published: June 2021

The multiple inert gas elimination technique (MIGET) [1] is the reference technique for assessing pulmonary gas exchange, but is not routinely used in clinical practice. The purpose of this study was to assess whether a simpler model of gas exchange, identifiable from clinical data, could simulate the effects of changing ventilator settings on arterial oxygenation in a comparable way to MIGET. Seven pigs were studied prior to and following lung damage with oleic acid, and at a range of ventilator settings. The MIGET and simple models were fitted to inert gas data, as described previously [2], and then used to simulate changes in arterial oxygenation on varying FiO2. Model simulations performed using MIGET and the simple model are comparable, the MIGET model simulating PaO2 values on average 0.22 kPa ± 0.59 (SD) higher than the simple model. Model simulations are also accurate with a difference between model simulated and measured values of PaO2 of 0.33 kPa ± 1.48 (SD) for the MIGET model, and 0.12 kPa ± 1.33 (SD) for the simple model. For oleic acid lung damage, the simple model provides a description of arterial oxygenation which is comparable to the MIGET over the clinically relevant range of PaO2.
Blockade of gap junctions markedly alters hypoglossal motor discharge in arterially‐perfused adult rat
Authors: Ono Kenichi , Solomon Irene C
Published: June 2021

In the arterially‐perfused adult rat, pharmacological blockade of gap junctions increases frequency, decreases amplitude, and in some cases, alters the pattern of phrenic bursts. The role of functional gap junction coupling in hypoglossal (XII) motor output in this preparation, however, remains to be identified. Therefore, we examined the effects of pharmacological blockade of gap junctions using carbenoxolone (CBX; 100 μM; n=20) on phrenic and XII nerve discharges in arterially‐perfused adult rats; experiments were also conducted using the inert analog glycyrrhzic acid (GZA; 100 μM, n=6) as a control for non‐specific effects of CBX. We found that perfusion with CBX (1) increased phrenic and XII burst frequency by significantly reducing both burst duration and the duration between bursts, (2) decreased phrenic and XII burst amplitude, and (3) shifted the time‐to‐peak to an earlier time point in the phrenic and XII bursts. The effects of CBX on XII burst timing and patterning were greater that those observed for phrenic bursts, with pre‐I XII discharge being markedly reduced or absent in most, but not all, XII bursts. In contrast, GZA was ineffective in similarly altering phrenic or XII activity. These data lend further support to a role of gap junctions in central respiratory control in adult rat, and suggest that the role of gap junction coupling in phrenic and XII motor control may not be identical. Supported by NS045321
A Lower NO‐RBC Reaction Rate Constant: Implications for the NO Biotransport in Microcirculation
Authors: Deonikar Prabhakar , Kavdia Mahendra
Published: June 2021

It is established that red blood cells (RBCs) consumption of nitric oxide (NO) is several folds lower than that of free hemoglobin (Hb).Using a novel bioreactor; we have recently reported (Deonikar and Kavdia, Ann. Biomed. Eng., 2009) a much lower NO‐RBC reaction rate constant of 0.2×105 M−1 s−1 than the previously reported reaction rate constants of 1.1 – 1.4 ×105 M−1s−1. In this study, we developed a computational model to simulate NO biotransport in an arteriole (50 μm ID) to evaluate the effect of the lower NO‐RBC reaction constant and blood flow rates on the NO concentration distribution in the arteriole. The luminal & abluminal NO concentration levels increased with a decrease in NO‐RBC reaction rate constant. The reduced NO‐RBC reaction rate constant increased the NO concentration to 280 nM in the smooth muscle cell layer, which is ~3‐fold as compared to the previously reported smooth muscle NO concentration. The model predicts that significant amount of luminal NO can be transported downstream at higher blood flow rates. These results indicate the possibility of luminal NO transport causing the modulation of vascular tone of downstream resistance vessels. Supported by: AHA 0530050N and NIH R01 HL084337 & R15 HL087287.
Metabolic modeling of acetate metabolism in the human brain
Authors: Shestov Alexander A , Deelchand Dinesh , Henry Pierre‐Gilles
Published: June 2021

Most 13C metabolic modeling studies have been performed using 13C‐glucose as the infused substrate. Acetate, a glial‐specific substrate, is an attractive alternative to glucose to study neuronal‐glial interactions [1,2]. The goals of the present study were to determine kinetic parameters for acetate transport and utilization and to perform dynamic metabolic modeling of glutamate and glutamine 13C turnover curves obtained during [2–13C]acetate infusion in the human brain with a two‐compartment neuronal‐glial model.

Results

Fitted values for acetate transport and uptake kinetics were: Vtrmax=0.300.07 μmol/g/min and Vutmax=0.170.03 μmol/g/min [3]. Metabolic fluxes determined from metabolic modeling of the glutamate and glutamine positional 13C time courses were (in μmol/g/min): VTCA(n)=0.680.20, VTCA(g)=0.090.02, VPC=0.000.01, VX=0.830.20 and VNT=0.140.03. These values are in agreement with rates reported in previous studies [2,4].

Conclusion

Dynamic metabolic modeling of glutamate and glutamine 13C turnover curves measured during [2–13C]acetate infusion with a two‐compartment neuronal‐glial model is feasible and allows determination of compartmentalized metabolic rates in human brain.
Histone biotinylation is a naturally occurring phenomenon
Authors: Wijeratne Subhashinee Samudra K. , Kuroishi Toshinobu , Pestinger Valerie , Rios‐Avila Luisa , Zempleni Janos
Published: June 2021

Modifications of histones such as methylation and acetylation are involved in gene regulation. We recently identified a diet‐dependent histone modification, biotinylation of lysines, mediated by holocarboxylase synthetase (HCS). HCS is a chromatin protein. Knockdown of HCS decreases histone biotinylation in human cells. We identified ten biotinylation sites in histones using histone‐based synthetic peptides and biotinylation site‐specific antibodies. A recent study (Healy et al., 2009) has questioned the occurrence of histone biotinylation in vivo. Here, we provide unambiguous evidence in support of histone biotinylation in a number of primary and transformed human cells. Our biotinylation site‐specific antibodies, unlike the commercial antibodies used by Healy, do not cross react with methylated and acetylated histones. We detected biotinylated histones in various cell lines using anti‐biotin, streptavidin, and target‐specific antibodies. Cells of the lymphoid lineage produced the strongest biotinylation signal, which might explain the failure to detect histone biotinylation in HeLa cells in Healy's studies. Current studies focus on detecting biotin in native histones using [3H]biotin, customized [14C]carbonyl‐labeled biotin, and mass spectrometry in Jurkat cells. (UNL ARD Hatch grant, NIH DK063945, DK077816, DK082476 and ES015206, USDA CSREES 2006‐35200‐17138, and NSF EPS 0701892.)
Differential effects of sulforaphane on histone deacetylases, cell cycle arrest and apoptosis in normal and prostate cancer cells
Authors: Clarke John , Yu Zhen , Ho Emily
Published: June 2021

Epidemiological data indicate that a diet high in cruciferous vegetables may lower the overall risk of prostate cancer. The ability of sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables, to inhibit histone deacetylases (HDAC) may be one mechanism by which it acts as a chemoprevention agent. Interestingly, the antiproliferative effects of pharmacological HDAC inhibitors are specific to cancer cells. The objective of this study was to compare the effects of SFN on HDAC inhibition and downstream molecular targets in both normal (PrEC) and cancerous (PC3) prostate epithelial cells. We hypothesize that SFN will act similar to pharmacological HDAC inhibitors and selectively target cancer cells. In PC3, SFN decreased HDAC activity, decreased HDACs 3, 6, and 8, increased acetylated histone H3 at the promoter for p21, induced p21 expression and increased tubulin acetylation. These data suggest that SFN targets both Class I and II HDACs in prostate cancer cells. In PrEC, SFN caused only a transient reduction in HDAC activity with no change in any other endpoints tested. SFN also induced selective cell cycle arrest and apoptosis in PC3 but not PrEC. We conclude that SFN exerts differential effects on HDAC activity and downstream targets in normal and cancer cells. Together, these data highlight the potential of SFN, a dietary HDAC inhibitor as an effective chemoprevention agent. Funded by NIHCA122906.

Grant Funding Source: NIHCA122906
All climate change is local: using physiology and biophysics to explore a changing world
Authors: Helmuth Brian
Published: June 2021

Understanding the mechanisms by which organisms respond to their physical environment is a powerful tool for forecasting the impacts of climate change on ecosystems. Despite the pervasive effects of climate change on a global scale, organisms respond physiologically and behaviorally only to the very local characteristics of their immediate environment. Predicting where, when and with what magnitude the likelihood of changes in community structure are likely to occur requires that we understand how large‐scale processes (“environmental signals”) are downscaled to the level of the organism.

Biophysical models (models that track heat inputs and outputs) provide a key tool for analyzing how environmental signals drive organism and ecosystem processes. Importantly, such approaches show that predictions cannot always be made through correlations with large‐scale signals, such as those measured by buoy or satellite. While such measurements are a vital tool for measuring environmental parameters over large spatial and long temporal scales, they are not sufficient for predicting organism responses. By understanding how factors such as body temperature interact with stressors such as nutrient load, fishing pressure and sedimentation, we can triage specific locations by modifying these latter stressors through effective management.
Myocardial contractile responses to hemodynamic stress are improved in heart failure rats fed high saturated fat
Authors: Berthiaume Jessica M , McElfresh Tracy A , Chen Xiaoqin , Bray Molly S , Hoit Brian D , Chandler Margaret P
Published: June 2021

Previous studies have reported that high dietary fat feeding in heart failure (HF) is associated with improved myocardial contractile function under baseline conditions. Our goal was to determine whether myocardial function is compromised in response to the stresses of varying preload & β‐adrenergic challenge in HF animals fed high fat. Male Wistar rats underwent ligation or sham surgery & fed normal (SHAM, HF) or high fat (SHAM+SAT, HF+SAT) for 8 wk. Contractile function was assessed at baseline, during IVC occlusions & graded dobutamine stress. Steady state indices of systolic function, LV+dP/dtmax, stroke work (SW) & LV max power were reduced in HF but increased in HF+SAT. Preload recruitable load independent measures of contractility slope of end systolic PV relationship, max elastance, preload recruitable SW and +dP/dtmax ‐ EDV were also decreased in HF but not HF+SAT. β‐adrenergic responses (ΔLV+dP/dtmax & Δcardiac output) were reduced in HF groups, but high fat did not further impact contractile reserve in HF. Contractile reserve was down in SHAM+SAT. Microarray gene expression results support the existence of classic genes markers of HF but do not implicate genes involved in cardiac metabolism. These results suggest that high fat feeding improves myocardial function at rest & during stress in HF, but may negatively impact contractile reserve under non‐pathological conditions (Grant: NHLBI HL‐081857)
Increase toll‐like receptor 4 expression after ischemia/reperfusion contributes to myocardial apoptosis: role of PI3Kγ/NFκB pathway
Authors: Xu Hu , Xu Xuemei , Zhang Jingchao , Su Zhaoliang , Martin Claudio M. , Rui Tao
Published: June 2021

This study is to explore increase toll‐like receptor 4 (TLR4) expression and its regulation pathway in the ischemia/reperfusion (I/R) ‐induced myocardial apoptosis.

Methods

TLR4 expression, PI3Kγ, NFκB and apoptosis were assessed in cardiac myocytes challenged with an anoxia/reoxygenation (A/R). In vivo, mice were subjected to coronary artery occlusion followed by releasing for myocardial I/R. Myocardial TLR4 expression, apoptosis were evaluated.

Results

A/R challenge resulted in increased TLR4 expression and myocyte apoptosis. Myocytes deficient in TLR4 did not show increase in myocyte apoptosis after A/R. PI3Kγ and p65 (a subunit of NFκB were phosphorylated in cardiomyocytes with A/R. The phosphorylation of p65 occurred after PI3Kγ. A/R‐induced p65 phosphorylation did not occur in myocytes deficient in PI3Kγ. Pretreatment of myocytes with MG132, an inhibitor of NFκB, prevented the A/R‐induced increase in TLR4 expression. I/R resulted in increase myocardial TLR4 expression and apoptosis. I/R‐induced myocardial apoptosis was attenuated in mice deficient in TLR4 and PI3Kγ.

Conclusion

Our results indicate increase in TLR4 expression contributes to I/R‐induced myocardial apoptosis. PI3Kγ/NFκB signaling pathway is pivotal in regulating TLR4 expression. (HSFO NA 6316)
Inhibition of bone morphogenetic protein protects against atherosclerosis and vascular calcification
Authors: Yao Yucheng , Bennett Brian J , Wang Xuping , Rosenfeld Michael E , Giachelli Cecilia , Lusis Aldons J , Bostrom Kristina I
Published: June 2021

The bone morphogenetic proteins (BMP), a family of morphogens, have been implicated in atherogenesis as mediators of inflammation and calcification. We investigated the role of altered expression of Matrix Gla Protein (MGP), an inhibitor of BMP, on the development of atherosclerotic lesions and vascular calcification using MGP transgenic or MGP deficient mice bred to apolipoprotein E (Apoe−/−) mice, a model of atherosclerosis. MPG overexpression reduced vascular BMP signaling, which resulted in reduced lesion size, and intimal and medial calcification. It was associated with reduced expression of the activin‐like kinase receptor (ALK)1 and the vascular endothelial growth factor (VEGF), part of a BMP‐activated pathway that also regulates angiogenesis. MGP‐deficiency, on the other hand, strongly enhanced vascular BMP signaling and expression of ALK1 and VEGF. Despite the high propensity of the Apoe−/− mice to develop lesions, lesion formation was minimal in the setting of MGP deficiency, which causes chondroosteogenic differentiation and calcification, suggesting that the abnormal cell differentiation did not allow for lesion formation. Together, our results indicate that vascular BMP signaling is a key regulator in the development of vascular disease, requiring careful control to maintain normal vascular homeostasis.

Research support: NIH/NHLBI, AHA.
IL‐19 decreases ox‐LDL induced VSMC activation by suppression of scavenger receptor expression and reduction of ox‐LDL uptake
Authors: Cuneo Anthony A. , Kelemen Sheri , Autieri Michael V.
Published: June 2021

Atherosclerosis is inflammatory in nature and oxidized low density lipoprotein (ox‐LDL) has activating effects on vascular smooth muscle cells (VSMC). Interleukin‐19 (IL‐19) is a recently described Th2 anti‐inflammatory cytokine. We have previously reported that IL‐19 expression is induced in VSMC by inflammatory cytokines and in arteries by injury. Our hypothesis is that IL‐19 participates in a negative autocrine regulatory feedback mechanism to ameliorate inflammation. The purpose of this study is to determine the molecular mechanism(s) of IL‐19's anti‐inflammatory role in atherosclerosis. IL‐19 decreases the abundance of ox‐LDL induced COX‐2 protein expression. Fluorescently labeled ox‐LDL uptake is inhibited by IL‐19, as determined by flow cytometry and immunocytochemistry. IL‐19 reduces the abundance of LOX‐1 and CX‐CL16 mRNA, VSMC receptors which internalize ox‐LDL. Each of these receptors have AU‐rich elements (ARE) in their 3' UTR which act as binding sites for the RNA‐binding protein HuR, an inflammatory mRNA stabilizing protein. The mRNA stabilizing function of HuR is linked to its cytoplasmic translocation. IL‐19 inhibits HuR protein abundance and ox‐LDL induced HuR cytoplasmic translocation. Together, these data indicate that at least one of IL‐19's anti‐atherosclerotic mechanisms in VSMC involves reduction of ox‐LDL uptake, primarily through reduced scavenger receptor abundance.

Work supported by grant HL063810 and HL090885 from NHLBI, and grant 0455562U from AHA, to M.V.A.. A.A.C. received NHLBI Ruth L. Kirchstein Predoctoral fellowship F30HL095329.