bluuebunny/crossref_metadata_2025 huggingface dataset:
Shift of the cardiovagal baroreflex response with maintained sensitivity during head up tilt
Authors: Schwartz Christopher E. , Medow Marvin S. , Messer Zachary , Baugham Ila L. , Terilli Courtney , Tambone Robert , Stewart Julian M.
Published: June 2021

Measurement of cardiovagal baroreflex gain is often evaluated using spontaneous fluctuations in blood pressure (BP) and R‐R interval. However, spontaneous indices (SI) only provide a slope of the baroreflex curve at operating points (OP) and may not adequately identify changes in sensitivity and range of reflex function produced by the reference standard modified Oxford (mod‐Ox) technique. We hypothesize that during head up tilt (HUT) the baroreflex centering point (CP) is reset with unchanged sensitivity and response range. The mod‐Ox comprised 100 μg sodium nitroprusside, followed 1 min later by 150μg phenylephrine administered intravenously to 12 subjects (4 male) supine and again after 5 min of 70° HUT. Supine vs upright sensitivity (26±2 vs. 28±3 ms/mmHg) and response range (1104±77 vs. 1010±66 ms) were unchanged by HUT, but the CP was right and downwards shifted. Supine, the OP was near the CP; thus mod‐Ox and SI gains (21±3 vs 23±3 ms/mmHg) were similar to the reflex sensitivity (26±2, slope at CP). In contrast, the upright OP was far from the CP and thus the mod‐Ox OP gain was markedly decreased (28±3 vs 9±4 ms/mmHg) compared to the sensitivity (slope at CP) and was not different from SI gain (7.3±2). The cardiovagal baroreflex is shifted with HUT. SI estimate OP mod‐Ox gains which are similar to baroreflex sensitivity when supine but markedly reduced during HUT. Supported by NIH HL‐091948 and HL‐074873.
Assessment of chronic sympathetic nerve recording using Data Sciences International telemetry
Authors: Stocker Sean D
Published: June 2021

The ability to assess sympathetic nervous system function in conscious animals has been hampered by the inability to chronically record sympathetic nerve activity (SNA). The present study tested the newly developed F50‐W‐F2 transmitter from Data Sciences. Male Sprague‐Dawley rats (300–400 g) were implanted with a PA‐C40 transmitter to measure arterial blood pressure, and a F50‐W‐F2 transmitter to record lumbar SNA. After 5 day recovery, >70% of animals had stable SNA recordings characterized by pulse‐synchronous bursts. Animals with viable SNA at Day 6 continued to remain viable for several weeks (average 34±6 days) including signals that persisted in 2 animals for 80+ days. To test the responsiveness of the transmitters, animals were water deprived for 48 hours. Water deprivation significantly increased mean arterial blood pressure (12±2 mmHg), rectified SNA (41±6%), and lumbar burst frequency (4±1 Hz). When water was provided, values returned to baseline levels within 24 hours. In subsequent weeks, the magnitude of the responses was reproducible. These findings suggest that the F50‐W‐F2 radiotransmitter for SNA is reliable and easy to integrate into existing platforms. The implantation success rate and long‐term viability suggest these transmitters may provide a distinct advantage over conventional approaches to study sympathetic function.
The role of the paraventricular nucleus (PVN) glia in the onset of renal wrap (RW) hypertension
Authors: Hammond Bradley , Northcott Carrie
Published: June 2021

The magnocelluar region of the PVN is a key brain region involved in blood pressure regulation. During hypertension we have found elevated levels of the excitatory neurotransmitter (NT) glutamate and reduced levels of inhibitory NT GABA within the PVN. Since reuptake of NT is chiefly regulated by glia, altered NT may occur via alterations in glia. We hypothesized that glia number in the PVN are altered and involved in the development of hypertension. The brains from onset RW hypertensive rats (7 day) and corresponding sham rats (147 ± 28 vs. 100 ± 13 mm Hg; p<0.05) were isolated and immunocytochemically stained for GFAP to evaluate glia cells within the PVN. Staining revealed an increase in total PVN glia cell number staining for GFAP in RW compared to sham rats (75 ± 10 vs. 85 ± 7; p < 0.05). Within the PVN magnocellular region there were a greater number of GFAP stained glia in the in RW compared to sham (32 ± 4 vs. 39 ± 4; p<0.05). Within the parvocellular region no differences in GFAP stained cell numbers were observed (43 ± 6 vs. 47 ± 6; p = 0.07). Increases in glia within the magnocelluar nucleus of the PVN during the onset of hypertension suggest a potential role for glia in alterations of NT in the PVN during hypertension. Further studies using glia inhibitors will provide additional evidence for the physiological relevance of glia in the PVN and their role in hypertension. NIH R00HL087927
The Role of Macrophage Migration Inhibitory Factor (MIF) in the Paraventricular Nucleus (PVN) During Acute Stress
Authors: Erdos Benedek , Clifton Rebekah , McCowan Michael L. , Sumners Colin , Scheuer Deborah A.
Published: June 2021

We previously demonstrated that MIF is upregulated by angiotensin II (AngII) in the PVN of normotensive animals and counteracts the pressor action of AngII. In contrast, AngII fails to upregulate MIF in spontaneously hypertensive (SHR) rats, but overexpression of MIF reduces blood pressure (BP) in SHRs. Here, we investigated whether MIF is involved in BP regulation in normotensive Sprague‐Dawley (SD) rats during acute stress and under resting conditions. BP was measured with telemetry and AAV2‐GFP (n=8) or AAV2‐MIF (n=8) was injected bilaterally into the PVN. Responses to 1hr restraint stress (RS) and 15 min water stress (WS, 1cm deep, 25 °C) were evaluated. Unlike in SHRs, MIF overexpression had no effect on baseline BP in SD rats, and did not influence the amplitude of BP and HR responses to RS or WS. However, recovery time following WS was shorter in MIF‐ vs GFP‐treated rats (24±2 vs 30±3 min). In addition, spontaneous baroreflex sensitivity (sBRS) analyzed by the sequence method tended to increase following MIF treatment (from 1.74±0.14 to 1.94±0.15 ms/mmHg, P=0.07), while power in the LF range of BP variability spectrum indicating sympathetic nervous system influence on vasculature tended to decrease (from 2.83±0.32 to 2.48±0.24 mmHg2; P=0.06). In conclusion, in normotensive animals, MIF overexpression has only subtle effects on BP regulatory mechanisms. Supported by NIH #HL93186 (MPI).
Blunted sensitivity of intracardiac ganglion neurons to nicotine in type‐2 diabetic rats
Authors: Liu Jinxu , Tu Huiyin , Li Yu-Long
Published: June 2021

Acetylcholine, a principal excitatory neurotransmitter at the intracardiac ganglionic synapse, acts on the nicotinic acetylcholine receptors (nAChRs) and induces the cell excitation in intracardiac ganglion (ICG) neurons. Our previous study showed that ICG neuron excitability was lowered by the decreased Ca2+ currents in high‐fat diet/low‐dose streptozotocin‐induced type‐2 diabetes mellitus (T2DM) rats. In the present study, we examined the effect of nicotine (a nAChR agonist) on Ca2+ currents and cell excitability in ICG neurons from sham and T2DM rats. Immunofluorescence data showed that there was no significant difference on the protein expression of nAChRs in ICG neurons from sham and T2DM rats. Using whole‐cell patch clamp technique, we found that nicotine concentration‐dependently increased ICG neuron excitation (action potential frequency) and the sensitivity of ICG neuron to nicotine in diabetic rats was lower than that in sham rats (EC50 value is 2.86 μM in T2DM rats and 0.48 μM in sham rats). Diabetes also decreased the response of Ca2+ channels to nicotine in ICG neurons, compared to sham rats. In addition, nicotinic receptor antagonist (100 μM hexamethonium) completely blocked the effect of nicotine on ICG neuron excitability and Ca2+ currents in sham and T2DM rats. Our results indicate that T2DM decreases the sensitivity of ICG neurons to nicotine.
Hepatic and renal sat‐1 and CFEX in ethylene glycol‐induced oxalate nephrolithiasis in rats
Authors: Burckhardt Birgitta Christina , Brzica Hrvoje , Breljak Davorka , Vrhovac Ivana , Micek Vedran , Lovric Mila , Schnedler Nina , Burckhardt Gerhard
Published: June 2021

The epidemiological incidence of oxalate (OX) nephrolithiasis is higher in men than in women. More than 85% of the body OX is produced in liver and then released into the systemic circulation by the action of sulfate‐OX exchanger sat1 in the hepatocyte sinusoidal membrane. In kidneys, sat1 in the proximal tubule basolateral membrane mediates OX uptake, whereas the chloride‐formate‐ oxalate exchanger CFEX in the brush‐border membrane finally extrudes OX into the urine. Here we used the model of ethylene glycol (EG)‐induced OX nephrolithiasis in adult male (M) and female (F) rats to study sat1, CFEX, and rate‐limiting enzymes of OX synthesis, alcohol dehydrogenase (Adh1) and hydroxy acid oxidase (Hao1). Compared to controls, EG‐treated animals exhibited higher concentrations of OX in plasma and urine and higher abundance of OX crystals in urine, with a M dominance. Sat1 protein in liver and kidneys, which was M‐dominant in control animals, in EG‐treated animals increased only in F rats, while sat1 mRNA stayed unchanged. CFEX mRNA in both organs was sex‐independent and unaffected by EG treatment. Adh1 and Hao1 mRNA in both organs remained also unchanged upon EG treatment. In conclusion, despite hyperoxaluria in EG‐treated animals, the expression of sat1 in M and of CFEX in both sexes was sufficient to handle the EG‐induced production and secretion of OX.
AVP infusion increases the expression of urea transporters and ER stress pathway genes in medullae of female mice with urinary concentrating defect
Authors: Booth Allyson , Cai Qi , Romero-Aleshire Melissa Jill , Chandra Surabhi , Brooks Heddwen L
Published: June 2021

Abnormal proliferation in collecting duct cells plays a crucial role in polycystic kidney disease (PKD) and in lithium‐induced renal dysfunction. Females with PKD demonstrate lower proliferation rates than males, resulting in a less severe phenotype. We previously reported that vasopressin induced an increase in renal cell proliferation in male AQP1KO mice in addition to ER stress gene activation. In this study we infused AVP for 14 days into female AQP1KO mice. AVP induced a small but significant increase in urine osmolality (155 mosmol/kgH20 vs control). 14 days AVP infusion significantly increased the expression of UTA1 and UTA3 mRNA 2.97 ± 0.29 and 3.34 ± 0.57, respectively, vs control. AQP2 and AQP3 mRNA also increased 3.52 ± 0.28 and 2.59 ± 0.23, vs control. AVP infusion significantly increased the mRNA expression of early growth response gene Egr‐1 2.49 ± 0.49 and transcription factors ATF3 and ATF4 mRNA; 4.91 ± 0.70, and 3.36 ± 0.25, vs control. AVP infusion significantly increased the expression of ER stress factor GADD153 mRNA 2.53 ± 0.41 vs control. AVP did not increase the mRNA expression of PCNA in female kidneys; PCNA is a marker of proliferation. These data suggest that vasopressin regulation of urea transporters is intact in female AQP1KO mice. Further studies will determine if vasopressin induced proliferative pathways are blunted in female AQP1KO mice.

Support: DK073611 (HLB)
Alterations of Zinc, Copper, and Magnesium Concentrations During and After Open Heart Surgery
Authors: YAN Ying-Qun , LIU Xiao-Cheng , JING Wen-Bin , BAI Xiao-Yan , YANG Qin , HE Guo-Wei
Published: June 2021

Trace elements such as copper (Cu), cobalt, and arsenic may contribute to myocardial dysfunction and Zinc (Zn) deficiency may increase the susceptibility of the phospholipid cell membrane to free‐radical damage and oxidative changes. Magnesium (Mg) is an important determinant of the resting membrane potential of cardiac cell membranes. We studied the concentration of these elements in cardiac surgery. Fifty‐four consecutive patients for elective coronary artery bypass grafting (CABG) (30) and valve replacements (VR) (24) were studied. Blood samples were collected every 30 min (T1–T5) during cardiopulmonary bypass (CPB) and postoperatively (T6–T9). Plasma Cu, Zn, and Mg were measured with flame atomic absorption spectrophotometry. The concentrations of Zn, Cu, and Mg were significantly different during and after CPB (p<0.01). The Zn concentration at T7 and T8 (p<0.01) and the Cu concentration at T1, T9 (p<0.05) were significantly different between two groups. However, the Mg concentration had no significant difference between two groups (p>0.05). In patients undergoing VR or CABG, the concentrations of Zn and Cu decreased considerably during CPB and recovered after CPB with more rapid recovery of Zn in CABG than VR patients whereas Cu concentration recovered more rapidly in VR patients. These may have significant clinical implications.

Supported by International S&T Cooperation Program of China 2009DFB30560; National Basic Research Program of China 2010CB529502; Tianjin Municipal S&T Com 09ZCZDSF04200 & 10JCYBJC26400; NSFC 81170148; GRF CUHK4789/09M; CUHK2041688.
Elevated Arterial Pressure in Conscious Water Deprived Rats: Role of Global and Regional Sympathetic Activity
Authors: Veitenheimer Britta , Osborn John
Published: June 2021

Mean arterial pressure (MAP) and plasma osmolality (Posm) are elevated during water deprivation (WD) in conscious rats. Studies in anesthetized rats suggest that elevated MAP during WD is due to osmotically driven increases in lumbar sympathetic nerve activity (SNA); however, renal and splanchnic SNA may also play a role. We investigated the role of global and regional SNA in elevating MAP during 48 hours of WD in conscious rats. MAP and heart rate (HR) were measured by telemetry before and during 48hr of WD. Global sympathetic blockade was achieved by chronic administration of the α1 and β1 adrenoceptor antagonists terazosin and atenolol, respectively. MAP was increased in vehicle treated rats (16±1 mmHg) at 48 hours of WD compared to baseline. This increase in MAP was significantly less in α1/β1 blocked rats (1±2 mmHg) despite similar changes in Posm and HR. In additional experiments, selective denervation of the splanchnic or renal vascular beds had no effect on the MAP response to 48 hr WD. We are currently investigating the contribution of the lumbar nerves and adrenal responses to increased MAP in WD. These data support the hypothesis that elevated MAP during 48 hours of WD is sympathetically mediated. However, neither splanchnic nor renal nerves are necessary for the MAP response to WD. Supported by HLR0164176.
Anandamide and its metabolites as novel natriuretic and antihypertensive lipids from the renal medulla
Authors: Ritter Joseph K , Li Cao , Xia Min , Li Caixia , Lichtman Aron , Li Pin-Lan
Published: June 2021

Anandamide (AEA) is an arachidonate derivative found at high levels in the kidney but its physiological roles in the regulation of renal function are not well understood. This study characterized the distribution of AEA and its metabolizing enzymes and assessed their functions in the kidney. AEA measured by LC‐MS/MS was higher in the renal medulla (Med) versus cortex (Cort) of C57BL6 mice. AEA infused into the medulla (15–60 nmol/kg/min) dosedependently increased the urine formation rate and sodium excretion. The effects were blocked by systemic infusion (0.1 μg/kg/min) of celecoxib, an inhibitor of cyclooxygenase 2 (COX‐2), which converts AEA to prostamide E2 (PE2). Western and IHC analyses of COX‐2 and the AEA‐hydrolytic enzyme, fatty acid amide hydrolase (FAAH), showed opposite patterns of expression in the kidney with FAAH higher in Cort and COX‐2 higher in Med. This was supported by differential conversion of AEA to PE2 and arachidonic acid by mouse kidney Med and Cort microsomes, respectively. In anesthetized normal mice, PE2 infused intravenously reduced mean arterial pressure, increased renal blood flow and antagonized effects of angiotensin II. These results suggest an important physiological role of AEA as an intrarenal natriuretic lipid and PE2 as a circulating lipid hormone from the renal medulla for the regulation of body fluid and arterial blood pressure. Supported by NIH grants DK54927 and DA009789
Identification of discrete single tight junction opening/closing events with ion channel‐like properties
Authors: Weber Christopher R , Shen Le , Wang Yitang , Wang Yingmin , Nelson Deborah J , Turner Jerrold R
Published: June 2021

Tight junctions establish the barrier to paracellular flux of ions and molecules. Recent quantitative studies of fluorescent‐tagged protein dynamics have shown that tight junction structure undergoes rapid and continuous molecular remodeling. While functional analyses have characterized charge‐ and size‐selectivity of the tight junction barrier, studies of submicron regions have been impossible due to the reliance of all available measures of barrier properties on population averages. To overcome this limitation, we studied submicron tight junction regions using high resolution patch clamp techniques. The data reveal stochastic, transient conductance increases (duration 1.4±0.2 ms, size 4.2±0.2 pS, frequency 13.4±0.4 s−1). Consistent with known selectivity of claudin‐2‐dependent pores, events persisted after replacement of Na+ with methylamine. Further, La3+ (a known inhibitor of claudin‐ 2 conductance) or stable claudin‐2 knockdown, but not transmembrane ion channel inhibitors, limited transient tight junction conductance increases. We conclude that the currents recorded correspond to trans‐tight junction channel openings and that tight junction channels have properties that resemble traditional ion channels. These single‐channel measurements will make biophysical definition of tight junction structure:function relationships possible with molecular resolution.
Role of serotonin in the pathogenesis of inflammatory bowel disease
Authors: Regmi Sushil Chandra , Kang Youra , Park Sumin , Park Su-Young , Kim Jung-Ae
Published: June 2021

Serotonin (5‐Hydroxytrytamine, 5‐HT) is a major gastrointestinal paracrine hormone and enteric neurotransmitter. Although it has been known that serotonin level is increased in the inflamed gut in patients with inflammatory bowel disease (IBD) which is characterized by an excessive release of several proinflammatory cytokines, its role in the pathogenesis of IBD has not been revealed. In this study, we investigated the molecular mechanism by which serotonin aggravates intestinal inflammation. In in vitro model of intestinal inflammation, serotonin induced adhesion of monocyte to HT‐29 colon epithelial cells in a concentration‐dependent manner, which was similar to TNF‐α. However, no additive effect was seen in case of co‐treatment of the cells with serotonin and TNF‐α. Rectal administration of serotonin into normal colon did not induce inflammatory response. However, exogenous serotonin aggravated the TNBS‐induced inflammation by increasing the expressions of chemokines and adhesion molecules. The enhanced expression of IL‐8 which is a pro‐inflammatory and pro‐angiogenic agent correlated to the increased neutrophil infiltration and angiogenesis in the colon tissues co‐treated with serotonin and TNBS. In addition, serotonin itself induced angiogenesis using in vivo chick chorioallantoic membrane (CAM) assay. In conclusion, our results indicate that abnormally increased serotonin acts as a pro‐inflammatory and pro‐angiogenic factor during intestinal inflammation.
The Gate Residue F101 regulates coupling of Na and sugar cotransport in hSGLT1
Authors: hirayama bruce a , Loo Donald D.F. , Jiang Xuan , Wright Ernest M
Published: June 2021

Ion‐driven cotransporters use the energy stored in the transmembrane electrochemical gradient to drive the substrate across the membrane. This mechanism enables the substrate to be accumulated in the cell, potentially to concentrations far higher than present in the extracellular milieu. The concentrative power of this system is governed by the magnitude of the electrochemical gradient and the coupling stoichiometry of the cotransporter, i.e., how many ions are cotransported with each substrate. The sodium glucose cotransporter hSGLT1 is tightly coupled, with 2 Na cotransported with each sugar. We have found that mutation of F101, a residue that forms one of the extracellular gates to the sugar binding site to Cys, results in a change in how hSGLT1 ties sugar translocation to Na transport. At low external [NaCl] the coupling stoichiometry remained 2Na:1sugar, but at high [NaCl] the stoichiometry increased to 4Na:1sugar, and was invariant for [sugar] from 0.05 to 3mM, and membrane potentials from −50 to −90mV. Under similar conditions wild‐type coupling remained 2Na:1sugar. This indicates that F101, and potentially other ‘gate’ residues, play a role in the transport mechanism greater than simple barriers. Supported by NIH grant DK 19567.
Effects of bioactive salmon peptides and fatty acids on cellular transport and secretion of adiponectin
Authors: DeClercq Vanessa , d'Eon Brandon , McLeod Roger
Published: June 2021

Plasma adiponectin levels are inversely related to several components of the metabolic syndrome and therapeutics that target adiponectin secretion are emerging. Consumption of fish oil is associated with improved metabolic profile, however, there is additional evidence that the protein component of fish may also have metabolic benefits. The aim of this study was to examine the effects of fish fatty acids and peptides on adiponectin assembly and secretion in differentiated 3T3‐L1 adipocytes. Treatment with polyunsaturated fatty acids (PUFAs) increased total cellular adiponectin levels but did not increase adiponectin secretion. In addition, two fractions of molecular weight fractionated (<1000 dalton) salmon peptides, but not cod peptides, stimulated adiponectin synthesis and secretion. Subcellular fractionation on sucrose density gradients revealed that the majority of cellular adiponectin is located in the endoplasmic reticulum (ER). Treatment of the cells with Brefeldin A prevented adiponectin secretion and caused cellular accumulation of the high molecular weight adiponectin oligomers. These data suggest that the ER is an important site of cellular adiponectin accumulation and that treatment with PUFAs or salmon peptides can increase adiponectin in this adipocyte model.

Grant Funding Source: Heart and Stroke Foundation of Canada and Natural Sciences and Engineering Research Council of Canada
Identification of biomarkers for GNE myopathy
Authors: Malicdan May Christine , Momma Kazunari , Nishino Ichizo , Noguchi Satoru
Published: June 2021

GNE‐myopathy is an autosomal recessive disorder characterized by muscle atrophy and weakness, and accumulation of amyloid proteins and rimmed vacuoles in myofibers. This disease is secondary to mutations in the GNE gene, which encodes an essential enzyme in sialic acid biosynthesis. Recently, we reported that the sialic acid treatment is effective to prevent myopathic phenotype in model mice. In translating these results to a clinical trial for GNE myopathy, there is a need for establishing indicators of disease state or therapeutic effects. In this study, we identified the molecular biomarkers in blood of GNE myopathic patients. We measured sialic acid content by HPLC and β amyloid content by ELISA, and examined proteomic change of albumin and IgG‐depleted plasma by differential 2D‐gel electrophoresis (DIGE). In sialic acid content in blood, average values of sialic acid contents in blood are 397 ± 27 nmol/ml and 861 ± 23 nmol/ml for patients (n=46) and controls (n=21), respectively (p<0.0001). In Amyloid measurement, the average values for Aβ1–40, Aβ1–42 are similar between patients (n=29) and control (n=8) (p=0.17 and p=0.82), however patients showed much variation in both amyloid contents, indicating blood amyloid levels raise in some patients. In proteomic analysis of patient specimens (n=6) and control (n=6), we identified several spots including serotransferrin, were shifted horizontally from acidic to basic side in patients, and some spots showed changes in expression. These results showed that the protein sialylation as well as the proteins showing difference in expression, including amyloid can be used as biomarkers for therapeutic trials.
Inhibition Of The Estrogen‐Mediated Cardiac Vagal Control Accounts For The Baroreflex Depressant Effect Of Chronic Nicotine In Female Rats
Authors: El-Mas Mahmoud M , El-Gowelli Hanan M , Fouda Mohamed A , El-gowilly Sahar M
Published: June 2021

We previously showed that chronic nicotine dose‐dependently attenuated reflex chronotropic responses in female rats. Here the hypothesis was tested that impairment of the estrogen‐dependent cardiomotor vagal control mediates the nicotine‐baroreflex interaction. Baroreflex curves relating changes in heart rate to increases (phenylephrine, PE) or decreases (sodium nitroprusside, SNP) in blood pressure were constructed in sham‐operated, ovariectomized (OVX), and estrogen‐replaced OVX (OVXE2) rats. Slopes of the curves were taken as a measure of baroreflex sensitivity (BRSPE and BRSSNP). In sham rats, nicotine (2 mg/kg/day for 14 days) produced no changes in basal BP but reduced BRSPE and BRSSNP, suggesting attenuation of reflex bradycardic and tachycardic responses. Compared with sham rats, OVX selectively decreased BRSPE but not BRSSNP and abolished the nicotine‐induced impairment of both responses. The effects of OVX were reversed after treatment with estrogen or with the estrogen receptor modulator raloxifene. Atropine reduced BRS to comparable levels in all rat preparations regardless of the estrogen or nicotine milieu. Thus, nicotine attenuates reflex chronotropic activity via inhibition of the estrogen‐mediated facilitation of vagal cardiomotor activity.

This project was supported financially by the Science and Technology Development Fund (STDF), Egypt, Grant No. 502.
Effect of Severe Burn and Disuse on Metabolism and Overall Activity Levels in Rats
Authors: Baer Lisa , Wade Charles E
Published: June 2021

Hypermetabolisn in burn patients is a complex state characterized by various responses. In the rodent, a hypermetabolic response has been demonstrated by an increase in food intake with a continued loss of body mass and fat. Hypermetabolic metrics such as core body temperature and activity levels have not been carefully examined. Using a rodent model of burn and disuse, we examined how core body temperature and activity, in relation to metabolic changes, are affected after burn and disuse. Male rats were randomized into two groups: Sham Vehicle (SV;n=6) and Burn Vehicle (BV;n=6). Ten days before burn, a transmitter was surgically implanted IP to measure core body temperature (T) and overall activity (A). Food intake and body mass (BM) were measured daily until 14 days after burn. Burn rats received a 40% total body surface area scald burn and immediately hindlimb unloaded. There were no differences in food intake, BM, T or A before burn. Food intake, T and A, were significantly reduced in BV from SV immediately following burn until day 5. After day 5, T and A were not different between BV and SV, showing similar resting energy rates. Body mass was reduced in BV from SV immediately after burn until day 14, however food intake was increased in BV over the last 4 days, showing a hypermetabolic response. These effects indicate that these changes are primarily metabolically influenced. (UT Health Science Center‐Houston CeTIR Dept Grant)
Comparative metabolic physiology of cynomolgus (Macaca fascicularis) and rhesus (Macaca mulatta): The nature of their naturally occurring diabetes and metabolic syndrome
Authors: Hansen Barbara C. , Wang Jian , Wang Xiaoli , Fang Yupeng , Wang Chen , Newcomb Jennifer , Linden Ellen , Higgins Paul B. , Gregoire Francine , Wang Yixin Jim
Published: June 2021

A direct comparison between cynomolgus and rhesus monkeys of the disease, diabetes, as it progresses naturally and spontaneously, has not been previously reported. Because of the importance of nonhuman primate models for the development of therapeutic agents for diabetes and related metabolic impairments, we have compared our two colonies of monkeys, rhesus in the USA and cynos in China to determine similarities and differences in the presentation of diabetes, its natural evolution, and its responses to therapeutic agents. Both are known to frequently and spontaneously develop adult‐onset obesity‐associated diabetes that appears to be the same disease, with the same complications and the same pathophysiology, as seen in humans. Compared to rhesus, cynos weigh approximately 2–3 kg less at the time of diabetes onset, and have lower levels of hyperinsulinemia (~15–20μU/ml) and hypertriglyceridemia (~50 mg/dl), but have similar levels of hyperglycemia, impairment of glucose tolerance, acute and late insulin responses during an IVGTT, reductions in insulin sensitivity (euglycemic clamps), and attenuation of glucose stimulated insulin release (GGI). Similar pharmacological responses to some antidiabetic agents show that they are both valuable models for the evaluation of efficacy in these metabolic diseases.
Enhanced maturation of induced pluripotent stem (iPS) cell‐derived neurons by astrocyte‐conditioned medium: roles of differential regulation of Ca2+ channel and GABAA receptor activities
Authors: Rushton David James , Mattis Virginia B , Svendsen Clive N , Arjomand Jamshid , Allen Nick D , Kemp Paul J
Published: June 2021

Astrocytes promote synaptogenesis in vitro, a development which may be crucial to generating appropriate stem cell derived models of neurodegenerative diseases. However, the mechanism(s) by which they exert such effects are currently unknown.

We investigated the influence of mouse striatal astrocyte conditioned medium, at 7, 14 and 21 days, on the differentiation and maturation of human iPS‐derived neuroprogenitors using whole‐cell patch‐clamp and Ca2+ imaging. Although the proportion of cells able to fire an action potential in response to depolarization was unaffected, the conditioned medium evoked: i) significant hyperpolarization of the membrane at rest; ii) upregulation of L‐, N‐ and R‐ type Ca2+ channel function, and; iii) a dramatic increase in the proportion of spontaneously active cells.

Increasing the extracellular [Ca2+] from 0.6 to 1.8 mM resulted in accelerated neurogenesis and mimicked the enhanced maturity seen with astrocyte conditioned medium. These effects were blocked using specific inhibition of N‐ and L‐ type Ca2+ channels or GABAA receptors.

Taken together, these data demonstrate a clear role for GABAA‐evoked depolarization, and consequent voltage‐gated Ca2+ influx, in the process of neuronal maturation, and suggest that astrocytes may promote synaptogenesis, at least in part, via increased gain of the GABA excitation pathway.

Funded by MRC and CHDI.
Mitochondrial Protein Synthesis Rates Measured by Proteome Dynamics
Authors: Shekar Kadambari Chandra , Dabkowski Erinne R , Ling Li , Ribeiro Rogerio F , Willard Belinda , Stanley William C , Kasumov Takhar
Published: June 2021

Recent studies by our group have established proteome dynamics of plasma proteins using deuterium (2H) labeled water and advance spectrometric methods. In our current study, we used high resolution LTQ Orbitrap mass spectrometry (MS) to assess cardiac mitochondrial proteome dynamics. For preselected time points (0, 3, 20, 40 & 60 days), rats were given a bolus of 2H2O (20 ìl of 2H2O/g body wt) followed by 5% 2H2O in drinking water, which gave 2.7% enrichment. Cardiac mitochondria were isolated and proteins separated by blue‐native gel electrophoresis. The bands were excised, tryptic digested, peptides analyzed by ion trap MS/MS and 2H incorporation was assessed by the high resolution MS. Nuclear encoded proteins in the electron transport chain were analyzed and had similar half lives (30±2 days for ATP synthase F1 beta, 42±2 for Cytochrome C oxidase subunit 4 and 37±6 for Ubiquinone Cytochrome C reductase Core 2), while the mitochondrial encoded protein Cytochrome C oxidase subunit 2 was 44±3 days, suggesting similar rate of synthesis for nuclear and mtDNA encoded proteins. Further, the Krebs cycle protein isocitrate dehydrogenase had a similar half life of 39±5 days. In contrast, heat shock protein 70 had a more rapid turnover (10±0.3 days). These data show that cardiac mitochondrial proteins have a relatively slow turnover for both nuclear and mitochondrial encoded proteins, but a faster turnover for stress proteins.
Reactive aldehydes formed from peroxidation of n‐6 and n‐3 PUFAs have differential effects on mitochondrial function in heart
Authors: Anderson Ethan J , Kwak Hyo-Bum , Mattox Taylor A , Katunga Lalage , Thayne Kathleen
Published: June 2021

Peroxidation of n‐6 and n‐3 PUFAs generates toxic aldehydes 4‐ hydroxynonenal (HNE) and 4‐hydroxyhexenal (HHE), respectively. The high content of PUFAs and ROS in mitochondria make them primary sources and targets of these aldehydes, particularly in oxidative tissues such as heart. The mitochondrial enzyme aldehyde dehydrogenase‐2 (ALDH2) is responsible, in part, for neutralizing these aldehydes. To determine whether HNE and HHE differ in their effect on mitochondrial function in heart, and if activation of ALDH2 can suppress these effects, mitochondria were isolated from rat heart (N=8) and treated with vehicle (CON), HNE or HHE in the presence or absence of Alda‐1 (100 μM; ALDH2 agonist). Maximal ADP‐stimulated O2 consumption (maxO2) supported by glutamate+malate (GM), pyruvate+malate and succinate was decreased ~70% by HNE in concentration (10–80 μM) and time‐dependent manner (P<0.05). maxO2 was not affected by HHE in identical treatments. Activation of ALDH2 with Alda‐1 attenuated the HNE‐mediated inhibition of GM‐supported maxO2 (P<0.05). Mitochondrial calcium tolerance (mCa2+) was reduced by HNE (−28.2 %) and HHE (−25.1 %) vs. CON (P<0.05), although much more HHE than HNE was required. Activation of ALDH2 did not restore mCa2+ to CON levels with either aldehyde. Collectively, these findings suggest that aldehydes derived from n‐6 PUFAs are more toxic to mitochondria than aldehydes derived from n‐3 PUFAs, and that activation of ALDH2 remains a provocative therapeutic target to suppress the cytotoxic action of HNE. (Supported by NIH grant HL098780 to EJA)
Matrix Metalloproteinase‐1 Mediated Upregulation of VEGFR2 in Endothelial Cells
Authors: Alsaigh Tom , Mazor Rafi , Schmid-Schonbein Geert
Published: June 2021

Matrix metalloproteinases (MMPs) have a critical role in vascular remodeling, tumor progression and angiogenesis. VEGFR2, the main receptor for VEGF, expressed on endothelial cells has a role in promoting cell survival, proliferation and angiogenesis. Since MMP‐1 expression is positively correlated with a variety of cancers, we tested the hypothesis that MMP‐1 has a direct effect on endothelial cells, specifically by increasing their levels of VEGFR2. Endothelial cells were treated with active MMP‐1 and analyzed for VEGFR2 mRNA, protein levels and specific signaling pathways governed by the receptor. We found that treatment with MMP‐1 significantly augmented mRNA levels and protein expression of VEGFR2 in endothelial cells. Furthermore, VEGF‐A dependent phosphorylation of intracellular signaling molecules such as ERK and Akt were higher in MMP‐1 treated cells. We conclude that MMP‐1 promotes VEGFR2 expression on endothelial cells and provides, at least in part, a mechanism by which MMPs in a tumor microenvironment can promote cell proliferation and angiogenesis.

Research supported by NIH grant HL 10881
Gliovascular and cytokine interactions modulate brain endothelial barrier in vitro
Authors: Ganta Vijay Chaitanya , Cromer Walter E , Wells Shannon R , Erdriech-Epstein Anat , Couraud Pierre-Olivier , Romero Ignacio A , Weksler Babette , Mathis James Michael , Minagar Alireza , Alexander Jonathan Steven
Published: June 2021

The glio‐vascular unit (G‐unit) plays a prominent role in maintaining homeostasis of the blood‐brain barrier (BBB) and disturbances in this unit may seriously damage BBB. The direct and indirect effects of cytokines on cellular components of the BBB are not yet clear. The present study compares the effects of cytokines and cytokine‐treated astrocytes on brain endothelial barrier. 3D transwell co‐cultures of brain endothelium and astrocytes were used to investigate gliovascular barrier responses to cytokines during pathological stresses. Gliovascular barrier was measured using trans‐endothelial electrical resistance, a sensitive index of in vitro barrier integrity. We found that neither TNF‐á, IL‐1â or IFN‐ã directly reduced barrier in human or mouse brain endothelium or ECV‐304 barrier, but astrocyte exposure to cytokines in co‐culture significantly reduced endothelial (and ECV‐304) barrier. These results indicate that human and mouse brain endothelial barrier may respond positively to cytokines alone, but that during pathological conditions, cytokines dysregulate the barrier indirectly through astrocyte activation involving reorganization of junctions, matrix, focal adhesion or release of barrier modulating factors (e.g. oxidants, MMPs).
Hypoxia Stimulates Pulmonary Artery Endothelial Proliferation via 5‐Lipoxygenase
Authors: Porter Kristi Michelle , Sutliff Roy L
Published: June 2021

Pulmonary Hypertension (PH) is a progressive disorder characterized by endothelial dysfunction and proliferation. Hypoxia induces PH by increasing vascular remodeling. A potential mediator in hypoxia‐induced PH development is 5‐Lipoxygenase (ALOX5). While ALOX5 metabolites have been shown to promote pulmonary vasoconstriction and endothelial cell proliferation, the contribution of ALOX5 to hypoxia‐induced proliferation remains unknown. We hypothesize that hypoxia exposure stimulates HPAEC proliferation by increasing ALOX5 expression and activity. Human pulmonary artery endothelial cells (HPAEC) were cultured under normoxic (21% O2) or hypoxic (1% O2) conditions for 24‐, 48‐, or 72 hours. In a subset of cells, the ALOX5 inhibitor, zileuton, was administered during hypoxia exposure. Cells were then harvested to assess ALOX5 expression via qRT‐PCR and western blot. HPAEC proliferation was assessed using an MTT assay and PCNA Western analysis. Our studies demonstrate that 24‐ and 48 hours of hypoxia exposure have no effect on HPAEC proliferation or ALOX5 expression. Seventy two hours of hypoxia significantly increases HPAEC ALOX5 expression and HPAEC proliferation. Zileuton administration attenuates hypoxia‐induced HPAEC proliferation. These studies indicate that hypoxia exposure induces HPAEC proliferation by activating the ALOX5 pathway.
Endothelin‐1 contributes to endothelial responses in newborn arteries
Authors: Heberlein Katherine R , Flavahan Sheila , Flavahan Nicholas A
Published: June 2021

Vascular disease is associated with reduced NO activity and a concomitant increase in endothelin‐1 (ET1) activity. The endothelium of newborn arteries has an unusual phenotype, including decreased NO activity. Experiments were conducted to determine whether newborn endothelium also had increased activity of ET1. Carotid arteries were isolated from newborn (postnatal day 1, P1), P7 and P21 mice, and analyzed in a myograph at a transmural pressure of 20 mmHg. The endothelial secretagogue A23187 caused marked constriction of newborn arteries (P1) that was abolished by endothelium‐denudation, or by inhibition of ET receptors (ETA BQ123, ETB BQ788) or of endothelin converting enzyme (SM19712, Phosphoramidon). In contrast, in P7 and P21 arteries, A23187 caused only dilation with no evidence of ET1‐mediated constriction. Exogenous ET1 caused similar constriction in P1, P7 and P21 arteries. Acute inhibition of NO synthase (LNAME) reduced dilator responses to A23187 in P1 and P7 arteries, but did not uncover ET1‐mediated constriction. In contrast, in P7 and P21 arteries from eNOS−/− mice, A23187 caused ET‐1‐mediated constriction. These results indicate that newborn arterial endothelium can generate ET1 constrictor activity. This activity decreases during early postnatal maturation of the endothelium, which appears to be mediated in part by increasing activity of endothelial NO. Funded by NIH HL102715
Sarcopenic obesity among young adult Asian‐American women: results from a serial‐cross sectional study of multiethnic college aged adults in Southern California
Authors: Carpenter Catherine L , Yan Eric , Chen Steven , Hong Kurt , Deng Maxwell , Li Zhaoping , Heber David
Published: June 2021

Obesity prevalence and average body composition measures vary according to U.S. gender and racial subgroups with Asian‐ American men and women having the lowest prevalence of obesity. However relying on body‐mass index (BMI) to estimate obesity prevalence may misclassify subgroups with normal weight sarcopenic obesity. Our objective was to evaluate percentage body fat and BMI to determine whether BMI reflects percent body fat consistently across different ethnic subgroups. We conducted a serial cross‐sectional study of 940 college students recruited from a public University in Southern California over four consecutive years. Percent body fat (PBF) was measured by bioelectrical impedance analysis (BIA) (Biodynamics, Inc, Seattle WA), weight measured by physicians’ scales, and heights with stadiometers. Our ethnic sample consisted of Asian (49%), Caucasian (23%), Hispanic (7%), and Other (21%). On average, participants were 21.4 years old, BMI was 22.9 kg/m2, and PBF averaged 24.8%. BMI and PBF varied significantly by race/ethnicity for men and women (p‐value = 0.002 and 0.005 for men; and 0.009 and 0.008 for women respectively). On average, Asian men had the lowest BMI (23.7 kg/m2), and the lowest percent body fat (18.9%) of the four racial/ethnic groups. Asian women had the lowest BMI (21.5 kg/m2) but the second highest percent body fat (27.8%), with Hispanic women having the highest PBF (29.9%) and the highest BMI (23.5 kg/m2). While our college‐aged study population was generally normal‐weighted, the high PBF with low BMI pattern exhibited by Asian American women suggests that this group could be at risk for obesity‐related disease and could escape detection if BMI is the sole measure used to estimate body composition. Funding was provided by the UCLA Department of Medicine.
NFkB signaling and inducible nitric oxide synthase activity during pulmonary ischemia‐reperfusion increase co‐localization of fibrinogen/fibrin and platelets at sites of vascular leakage in rabbit lung
Authors: Dixon James T , Gozal Evelyne , Sachleben Leroy R , Lominadze David , Juniel Charla L , Roberts Andrew M
Published: June 2021

Platelet adhesion and fibrinogen/fibrin (Fg/Fb) deposition cause endothelial dysfunction during acute lung injury. We examined the hypothesis that during pulmonary IR, platelet activation, recruitment of Fg/Fb to the vascular wall and subsequent leakage are associated with NFκB and inducible nitric oxide synthase (iNOS) activation pathways. Subpleural microvessels and alveoli were examined by video microscopy of the right lung in anesthetized rabbits with open chest and ventilated lungs. IR was caused by occluding the right pulmonary artery for 2 h. Injection of fluorescently labeled albumin and a polyclonal antibody to Fg/Fb into the pulmonary circulation via the right atrium during early reperfusion revealed areas of microvascular leakage and interstitial edema associated with Fg/Fb deposition. Platelets were detected by immunohistochemistry of tissue samples at sites of vascular leakage in conjunction with Fg/Fb. On average, IR (n=3) caused a 6–7 fold increase in albumin leakage, platelet adhesion, and albumin‐Fg/Fb‐platelet co‐localization compared to control. Additionally, IR increased NF‐κB activation in lung lysates as detected by phosphorylation of IκB. These effects were attenuated by treatment with an iNOS activity inhibitor (1400W) before IR. Our data suggest that NFκB and iNOS activation may play a critical role in the regulation of platelet Fg/Fb–induced microvascular leakage during pulmonary IR. Supported in part by American Lung Association‐Kentucky to AMR and NIH grant #HL080394 to DL.
The effect of β2 adrenergic‐receptor stimulation on lung fluid balance in heart failure
Authors: Taylor Bryan Joseph , Ceridon Maile , Snyder Eric , Olson Thomas , Johnson Bruce David
Published: June 2021

Background

Increased pulmonary capillary pressure and a possible desensitization of lung β2 adrenergic receptors (β2AR) involved in fluid removal mechanisms may increase extravascular lung water (ELW) in stable heart failure (HF) patients. Whether these patients exhibit increased ELW remains controversial.

Purpose

To determine if HF patients have elevated ELW versus controls (CTL) and if acute β2AR agonist inhalation stimulates fluid removal.

Methods/Results

14 stable HF patients and 19 healthy age/gender matched CTL were studied. Lung tissue volume (Vtis) (includes tissue, blood and water) and pulmonary capillary blood volume (Vc) were assessed pre and post nebulized albuterol via CT and rebreathe, respectively. ELW was derived as Vtis – Vc. Pre albuterol, ELW was greater in HF vs. CTL (861±241 vs. 739±143 ml, P<0.01), with no difference in Vtis (938±246 vs. 830±151 ml, P=0.08). Albuterol decreased Vtis (–4±2%, P=0.02) but did not change ELW (739±143 vs. 724±132 ml) (P>0.05) in CTL. In HF, albuterol decreased both Vtis (–5±3%) and ELW (– 4±2%) (P<0.05). There was a negative relationship between baseline values and the pre to post albuterol change for Vtis (r2=0.38) and ELW (r2=0.42) (P<0.01) in HF.

Conclusion

Lung fluid is elevated in stable HF patients relative to healthy subjects. Stimulation of β2ARs appears to enhance fluid removal in HF, especially in patients with elevated lung water at rest.
Lack of PEDF promotes a proinflammatory phenotype in lung endothelial cells
Authors: Shin Eui Seok , Sorenson Christine M , Sheibani Nader
Published: June 2021

Pigment epithelium‐derived factor (PEDF) is a multifunctional protein with important roles in regulation of inflammation and angiogenesis. It is produced by various cell types including endothelial cells (EC). However, the cell autonomous role PEDF plays in regulation of EC function remains elusive. Here we prepared lung EC from wild type (PEDF +/+) and PEDF‐deficient (PEDF−/−) mice and determined the impact of PEDF‐deficiency on EC function. We show that PEDF−/− EC are more migratory and fail to undergo capillary morphogenesis in Matrigel compared to PEDF+/+ EC. Although no significant differences were observed in the rates of apoptosis of PEDF−/− EC compared to PEDF+/+ EC, PEDF−/− EC proliferated at a slower rate. PEDF−/− EC also expressed increased levels of proinflammatory markers including VEGF, iNOS, VCAM‐1, as well as exhibiting altered cellular junctional organization. Lack of PEDF expression resulted in increased adhesion of EC to extracellular matrix proteins, including collagen IV, fibronectin and vitronectin. These changes were associated with decreased expression of α1, α6 and α7 integrins in PEDF−/− EC. PEDF−/− EC also expressed decreased levels of thrombospondin‐2, tenascin‐C and osteopontin while that of fibronectin was increased. Together our data suggest that PEDF modulates EC pro‐inflammatory and pro‐angiogenic properties by suppressing the inflammatory phenotype of EC. (NIH/EY18179, EY21357, ADA/1‐10‐BS‐160)