bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of doxorubicin administration on intramuscular nitric oxide concentration in rat skeletal muscle (1102.28)
Authors: Lalanne Josee , Fabris Sergio , MacLean David 
Published: June 2021

Doxorubicin (DOX) is a frontline anticancer therapeutic which has proven effective in the treatment of breast cancer. However, very little is known regarding the effects that DOX has on skeletal muscle metabolism, specifically its influence on nitric oxide (NO) production. Therefore, the purpose of the present study was to determine NO concentrations in the plantaris (P, n =6) and gastrocnemius (G, n =6) muscles of Sprague‐Dawley rats after DOX administration at a single dose of 1.5 mg/kg. Muscle samples were collected at 24, 48, 72, 96, 120, 144, 168 and 192 hours post injection. . Following administration, intramuscular NO increased (P<0.05) in the G after 120 (0.99±0.04 mmol/kg dw), 144 (0.91±0.03 mmol/kg dw) and 168 hours (0.79±0.03 mmol/kg dw) compared to control (0.62±0.07 mmol/kg dw). Similarly, NO increased (P<0.05) in the P after 120 (0.89±0.02 mmol/kg dw) and 144 hours (0.89±0.03 mmol/kg dw) compared to control (0.66±0.08 mmol/kg dw). Other than the observation that NO remained higher in the G but not in the P group at 168 hr, there were no other differences between fiber types. These data clearly suggest that DOX administration stimulates intramuscular NO production in a time dependent manner. In addition, these findings may represent the first step in better understanding NO deregulation in skeletal muscle upon DOX administration.Grant Funding Source: Supported by NSERC
Temporal variation in skeletal muscle atrophic pathways following transection of the sciatic nerve (1102.31)
Authors: Callahan Zachary , Menke Chelsea , Schaeffer Paul 
Published: June 2021

The purpose of this study was to investigate the temporal changes in gene expression and morphology in muscles of the hindlimb following transection of the sciatic nerve. A sham surgery was performed on the contralateral limb and was used as a control. Mice were sacrificed 3, 10, 28, or 56 days after surgery. There was no significant difference in muscle mass between sham and transected limbs at 3 days post‐surgery, but tissue mass was significantly lower following transection at the other three time points. Transected muscle mass stabilized by 28 days post‐surgery with no further loss. Myocellular cross sectional area was significantly smaller at 28 and 56 days post‐transection surgery. Additionally, tissue fibrosis area was significantly greater at 56 days post‐transection. In transected muscle, gene expression analysis revealed higher expression of MAFbx and MuRF‐1 (genes involved in atrophic pathways) at 3 days post‐surgery while expression was significantly lower at 28 days post‐surgery. We saw no difference in gene expression of Fox01 or Fox03 (two upstream regulators of MAFbx and MuRF‐1) for any of the conditions. Western blot analysis revealed that MuRF‐1 protein expression was significantly higher in transected muscle at all times except 56 days post‐surgery. Fox01 protein expression in transected tissues was significantly lower in 10, 28, and 56‐day groups. These data suggest that the transection of the sciatic nerve results in the activation of pathways that initially increase atrophy, but that long‐term effects are less clear.*This work was supported by NIH grant number 1R15DK085 497‐01A1.Grant Funding Source: Supported by NIH grant number 1R15DK085 497‐01A1
An excitatory projection from median preoptic area to the dorsomedial hypothalamus contributes to the activation BAT thermogenesis (1104.28)
Authors: Tupone Domenico , Morrison Shaun 
Published: June 2021

Disinhibition of brown adipose tissue (BAT) sympathoexcitatory neurons in the dorsomedial hypothalamus (DMH), by reduced discharge of their input from GABAergic, in the preoptic area (POA), is thought to be a key step in the cold‐defense and febrile activations of BAT sympathetic nerve activity (SNA) and BAT thermogenesis. Here we present evidence supporting the hypothesis that a population of median preoptic area (MnPO) neurons projecting to the DMH provides the excitatory drive to DMH neurons that is essential for cold‐defense and febrile BAT thermogenesis.To determine if the MnPO contains putative BAT thermogenesis‐promoting neurons that are activated during cold exposure and project to DMH, we injected the retrograde tracer, CTb into DMH and exposed the rats to a cold (10°C) ambient temperature to elicit BAT thermogenesis. We observed a larger number of c‐fos and CTb immunoreactive neurons in the MnPO of cold‐exposed rats than in those maintained at 25°C, confirming the existence of cold‐activated neurons in MnPO that project to DMH. In urethane/chloralose‐anesthetized, Wistar rats, bilateral nanoinjection of the GABAA agonist, muscimol (120nl, 1mM), into the medial preoptic area (MPA), a region containing warm‐sensitive neurons, did not decrease cold‐evoked BAT SNA, consistent with the hypothesis that the MPA is not the source of DMH excitation required for BAT thermogenesis. However, subsequent nanoinjection of muscimol (120nl, 1mM) into the MnPO completely reversed cold‐evoked BAT SNA. Moreover, in other experiments, the activation of BAT SNA following PGE2 nanoinjection into MPA was also inhibited by muscimol nanoinjection into MnPO. These data demonstrate that the MnPO contains essential thermogenesis‐promoting, BAT sympathoexcitatory neurons.Grant Funding Source: NIH NS40987
The effect of the head or neck cooling on body core temperature and thermal sensation in humans (1104.6)
Authors: Matsuda‐Nakamura Mayumi , Wada Satoshi , Marui Shuri , Sato Nobuo , Nagashima Kei 
Published: June 2021

Some animals have mechanisms that selectively cool the brain during hyperthermia. However, it remains controversial if humans have the mechanism. In the present study, we investigated the effect of the head or neck cooling on tympanic temperature as an indicator of brain temperature in normothermic and hyperthermic conditions. Eight healthy male subjects performed four local cooling trials (facial fanning, cooling of the forehead and neck, and the control). Subjects sat on a chair, putting on a water‐perfusion suit to maintain skin temperature at 33°C (normothermic condition) or 38°C (hyperthermic condition). Tympanic, esophageal, and skin temperatures were continuously monitored. Temperature sensation and thermal pleasantness were reported by the subjects. After 10‐min baseline period, local cooling was conducted for 15 min. During the head or neck cooling, the local skin temperature significantly decreased, however, there was no significant difference between tympanic and esophageal temperatures in normothemic condition. Only in hyperthermic condition, a significant difference between tympanic and esophageal temperatures was observed. After facial fanning, tympanic temperature was lower than esophageal temperature. While facial fanning produced a slight change in thermal pleasantness in normothermic condition, facial fanning produced a clear “pleasant” feeling in hyperthermic condition. These results may suggest that facial fanning cools the brain in hyperthermic condition. However, local skin cooling of the forehead and neck may not effect on the selective brain cooling.Grant Funding Source: This study was supported by JSPS KAKENHI Grant Number 25870831
Acute intermittent hypoxia alters leptin signaling pathways in arcuate nucleus (1107.1)
Authors: Moreau Jason , McCoy Aaron , Jones Douglas , Ciriello John 
Published: June 2021

The effect of acute intermittent hypoxia (AIH) on central pathways involved in metabolic homeostasis was investigated in male wild type Sprague‐Dawley (WT) or leptin deficient (Kilo rat; a homozygous knockout of the leptin gene) rats. Rats were exposed to AIH (8 h) or normoxic control conditions and their hypothalamic arcuate nuclei (ARC) were assessed for changes in protein signaling associated with satiety. AIH reduced body weight, food intake and active cycle locomotion without altering adipose tissue mass compared to WT normoxic controls. These differences were not present in Kilo rats. Plasma concentration of leptin was significantly increased after AIH in WT rats, but was not detectable in the Kilo rat. In ARC, phosphorylation of STAT3 and pro‐opiomelanocortin (POMC) expression were higher in the AIH WT rats, but these differences were absent in Kilo rats. Additionally, POMC‐expressing neurons were activated as determined by immediate early gene FRA‐1/2 expression in the AIH WT rats. Finally, ERK1/2 and its phosphorylation were lower in response to AIH in the WT rat, but these differences were eliminated in the Kilo rat. These data suggest that AIH induces significant alterations to body energy balance through changes in the secretion of leptin which exerts effects on satiety‐inducing pathways within the hypothalamus. Supported by HSF of Ontario.Grant Funding Source: Heart and Stroke Foundation of Ontario
Molecular support for high paracellular absorption in the intestine of flying mammals (1109.18)
Authors: Caviedes‐Vidal Enrique , Brun Antonio , Fernández‐Marinone Guido , Gatica‐Sosa Claudia , Price Edwin , Amweg Ayelen , Ortega Hugo , Karasov William 
Published: June 2021

Flying mammals absorb water‐soluble nutrients (e.g. glucose) at the intestine mainly by the paracellular route [across tight junctions (TJ) between adjacent enterocytes], while non‐flying mammals mainly rely on the transcellular route (across cell membrane using transporter proteins). We predicted that insectivorous bats Tadarida brasiliensis, compared to Mus musculus, would show enhanced expression of CLDN‐2 (CLDN=claudin) and OCLN (occludin) TJ proteins, which have been described as responsible for the permeability of polar water‐soluble solutes. We assessed the level and spatial distribution of CLDN‐2, ‐3, ‐5, ZO‐1 and OCLN by immunohistochemistry along the villus axis in the proximal intestine. Immuno‐specificity of the antibodies was checked by western blot. No differences were found for CLDN‐3 and ZO‐1 between species. We confirmed low expression of CLDN‐2 in mice (Holmes et al. 2006, Gene Expr Patterns 6: 581‐8; no signal detected in our preparations), but in bats the villus tips exhibited CLDN‐2. OCLN was expressed along the entire villus axis but with a stronger signal for the bat than for mice, giving additional support to our prediction. A third difference was that CLDN‐5 was strongly expressed along the villus in bats, whereas in mice its presence was not detected. Findings suggest potential molecular mechanism(s) underlying the observed higher paracellular absorption in bats compared to mice.Grant Funding Source: NSF IOS 1025886
Measurements of the stomachs and duodenums of fasted and sated rats (1110.2)
Authors: Lorber Mortimer 
Published: June 2021

Rats feed until sated. Thus, gastric and duodenal dimensions likely increase. Under Na pentobarbital the stomach and proximal duodenum were exposed via a midline incision. Measurements were made by a calipers and digital micrometer. Eight fasted adult females and eight which ate chow until sated, as judged by pausing or preparation for sleep, were studied. They ate (mean + s.d.) 4.74 + 1.17 g of chow. Body weights and visceral dimensions were compared by unpaired t‐tests. A P value < 0.05 was deemed significant. The fasted:sated mean + 1 s.d. values were: Body Weight (g) 186 + 9:195 + 10 (ns). Gastric values (cm): Width 1.94 + 0.13: 3.86 + 0.53; Rostrocaudal Height 1.78 + 0.15: 2.84 + 0.30; Dorsoventral Thickness 0.73 + 0.16: 1.70 + 0.25. (P < 0.001 for all). Proximal duodenal values (cm) were: Rostrocaudal Height 0.53 + 0.09: 0.55 + 0.17 (ns); Dorsoventral Thickness could not be obtained because the proximal duodenum is bound to the peritoneum. Separation would be unphysiological. All fasted rats but one had dorsoventrally concave duodenums. All sated rats but one had flat duodenums, suggesting some gastric emptying had occurred. The ratios of mean sated:fasted dimensions were 1.99 for Width, 1.60 for Height, and 2.33 for Thickness. Thus, the stomach markedly thickens. Its height increases least and its width, which doubles, is intermediate. In achieving satiety the rat stomach enlarges both significantly and anisotropically. ,Grant Funding Source: Personal
Butyrate increases and propionate decreases the frequency of propulsive contractions in guinea pig proximal colon (1110.7)
Authors: Hurst Norm , Kendig Derek , Murthy Karnam , Grider John 
Published: June 2021

INTRODUCTION: Colonic bacteria produce short‐chain fatty acids (SCFAs) by fermentation of dietary carbohydrates and fiber. The production of SCFAs is greatest in proximal colon where propulsion is likely to be highly dependent on chemical/nutrient stimuli. AIM: To determine the effect of individual SCFAs on propulsive contractions in guinea pig proximal colon. METHODS: Proximal colon was excised, cannulated and placed in Kreb’s buffer in an organ bath. After equilibration, the colon was distended with 1 ml of Krebs’s buffer alone or containing sodium salts of acetate, butyrate, or propionate at 10‐100 mM. Motility was videorecorded, spatiotemporal maps generated, and the number of full‐length propulsive contractions during a 5 min period determined. RESULTS: The basal rate of propulsive contractions in Kreb’s buffer was 2.9±0.7 per 5 min. Butyrate and propionate had concentration‐dependent and opposing effects on propulsive contractions; acetate had no effect. Butyrate significantly increased propulsive contractions (maximal increase of 207% (p<0.05) at 30 mM) whereas propionate abolished propulsive contractions (91‐100% inhibition at 10‐30 mM). Control Kreb’s buffer containing 10‐100 mM NaCl had no effect. CONCLUSION: SCFAs have differential effects on propulsive contractions in guinea pig proximal colon with butyrate being excitatory and propionate being inhibitory.Grant Funding Source: Supported by DK34153
Upregulation of L‐type calcium channel function in the colon of P/Q‐type calcium channel deficient mice (1110.9)
Authors: Rodriguez‐Tapia Eileen , Fried David , Galligan James 
Published: June 2021

The objective of this study was to examine the role of P/Q‐type voltage‐gated calcium channels (VGCCs) in enteric neuromuscular transmission in mice with a spontaneous mutation in P/Q channels (tottering, tg mice). Methods: Intracellular recordings of inhibitory junction potentials (IJPs) were obtained from circular muscle cells in segments of distal colon maintained in vitro. IJPs were evoked by a brief train of electrical stimulation (1s, 10 Hz, 10‐90 volts). Results: Electrical stimulation produced a voltage dependent increase in IJP amplitude and duration. IJPs were significantly larger in tissues from tg mice. Nifedipine (L‐type calcium channel blocker 1 μM) did not change IJPs in tissues from WT mice but it reduced IJPs in tissues from tg mice by 40 and 32% (P<0.05) at 60 and 70 V stimulation respectively. Conclusions: These results suggest that absence of functional P/Q‐type VGCCs causes an upregulation of L‐type calcium channel in the colon of tg mice. This could occur in inhibitory motorneurons, smooth muscle cells or both.Grant Funding Source: Supported by R01DK094932
Ligand‐directed activation of extracellular signal‐regulated kinases (ERK1/2) in enteric neurons (1114.1)
Authors: Duraffourd Celine , Kumala Erica , Anselmi Laura , Brecha Nick , Sternini Catia 
Published: June 2021

Opioids, acting at µ opioid receptors (µORs) are commonly used for chronic pain treatment. Opioids differ in their efficiency to induce µOR internalization, a key event in receptor signaling and function. Here, we tested the effect of opioids with different internalizing efficiency on the activation of the ERK family of Mitogen‐Activated Protein Kinases (MAPKs), a µOR downstream signaling, in enteric neurons, which mediate constipation, a major side effect of chronic opioids. Cultured rat myenteric neurons were stimulated with μOR‐internalizing agonists (the endogenous opioid analogue DAMGO or fentanyl at 1 µM), or morphine (10 µM) a poor internalizing agonist, for 0‐30 min at 37oC. ERK1/2 phosphorylation was determined by Western Blot with phospho‐p44/p42 and total ERK1/2 antibodies. DAMGO and fentanyl, but not morphine induced a rapid and transient ERK1/2 activation, which was blocked by naloxone, MAPK inhibitor, hypertonic sucrose, dynamin inhibition or mutation. To determine the effects of chronic µOR activation on ERK1/2 phosphorylation, cells were treated with 10 µM morphine or 1 µM fentanyl for 4 days before exposure to DAMGO, fentanyl or morphine. In enteric neurons chronically treated with morphine, DAMGO, fentanyl and morphine induced ERK1/2 activation, whereas in enteric neurons chronically treated with fentanyl only DAMGO and fentanyl induced ERK1/2 activation. Chronic morphine induced activation of the transcription factor, cAMP response element‐binding protein (CREB), which was abolished by MAPK pathway blockade. Chronic µOR activation induces ligand‐dependent changes of µOR downstream signaling, which are likely to contribute to the development of opioid‐induced constipation.Grant Funding Source: NIDDK54155 and 41301
Sirtuin 1 induces autophagy to suppress liver ischemia/reperfusion injury in mice (1115.1)
Authors: Biel Thomas , Flores‐Toro Joseph , Dean Joseph , Law Brain , Zendejas Ivan , Behrns Kevin , Kim Jae‐Sung 
Published: June 2021

Autophagy clears dysfunctional proteins and organelles in a timely manner. Defective autophagy and subsequent mitochondrial dysfunction is a key mechanism of I/R injury to the liver. Sirtuin 1 (SIRT1) is an NAD+‐dependent deacetylase that induces longevity and stress resistance, but the role of SIRT1 in hepatic I/R is unknown. Immunoblotting analysis after in vivo I/R of human and mouse livers and simulated in vitro I/R of mouse hepatocytes revealed that ischemia decreases SIRT1 to less than 20% of normal values, which is not recovered by reperfusion. I/R, however, did not decrease the expression of mitochondrial sirtuins such as SIRT3 and 5. Biochemical analysis showed that SIRT1 depletion during I/R is mediated by multiple proteases, including calpains. Specific overexpression of SIRT1 mitigated defective mitochondrial autophagy, onset of the mitochondrial permeability transition, and subsequent hepatocyte death after both in vitro and in vivo I/R. In striking contrast, hepatocytes from SIRT1 knockout mice were significantly susceptible to I/R injury. Thus, our results suggest that SIRT1 suppresses I/R injury in the liver by enhancing mitochondrial autophagy.Grant Funding Source: NIH DK079879, DK090115, EY019688, HL064024 and AG028740
The impact of P‐selectin deficiency on obesity‐associated non‐alcoholic fatty liver disease (1116.8)
Authors: Kuo Chao Yu , Day Yuan Ji , Hung Li Man 
Published: June 2021

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the worldwide, and occurs in patients who do not abuse alcohol. Metabolic syndrome is a major risk in the progression of NAFLD, steatosis and NASH (nonalcoholic steatohepatitis). In addition, obesity induced chronic low‐grade inflammation also play a crucial role in NAFLD formation. P‐selectin, an adhesion molecule, regulates leukocyte aggregation to vascular endothelium cell, induces the initial inflammatory response. In the study, we aimed to investigate the impact of P‐selectin deficiency on high fat diet (45% caloric from fat, HFD) induced NAFLD. C57BL6 wild‐type mice and P‐selectin KO mice were randomly divided into four groups, and fed with normal chow diet or HFD : wild‐type fed with chow diet (C) or high‐fat diet (H), P‐selectin KO mice fed with chow‐diet (PC) or high fat diet (PH). After 8 weeks HFD feeding, significantly increase body weight in wild‐type mice. The mice also exhibited higher liver weight, hyperglycemia, hyperinsulinemia and hyperlipidemia. Compared with the chow diet fed animal, the high fat diet impaired glucose tolerance and insulin sensitivity, enhanced glucose‐stimulated insulin secretion. High fat diet also induced plasma aspartate aminotransferase (AST) and alanine aminotranferease (ALT) elevation with imply hepatocyte damage. HFD promoted NF‐κB related inflammatory signaling in liver. However, P‐selectin KO mice reversed high‐fat diet induced AST, ALT elevation and NF‐κB inflammatory pathway in liver.P‐selectin KO mice also exhibited lower body weight, improved glucose intolerance and insulin resistance. Our studies indicate that P‐selectin is a crucial metabolic inducer. Deletion of P‐selectin correct high fat diet induced metabolic disturbance, liver injury and slow down the progression of NAFLD.
Age and SPARC dependent cardiac collagen changes (1120.7)
Authors: Toba Hiroe , de Castro Brás Lisandra , Weintraub Susan , Jin Yu‐Fang , Bradshaw Amy , Lindsey Merry 
Published: June 2021

Secreted protein acidic and rich in cysteine (SPARC), a collagen‐binding matricellular protein, has been implicated in procollagen processing. The aim of this study was to investigate age and SPARC dependent changes in cardiac extracellular matrix (ECM). We studied 6 groups of mice (n=4/group): young (4‐5 month old), middle‐aged (11‐12 m.o.), and old (18‐23 m.o.) C57BL/6J wild type and SPARC‐null mice. The left ventricle was decellularized in 1% SDS with protease inhibitors in PBS to enrich for ECM proteins. Protein extracts (10 μg) were separated by SDS‐PAGE, digested in‐gel and analyzed by HPLC‐ESI‐MS/MS. Relative quantification was by spectral counting (Scaffold). We identified 321 proteins, of which 27 proteins were ECM or ECM‐related proteins. Of these proteins, 16 showed age‐dependent changes. Collagens I, III, IV and VI, dystrophin, and laminin b2 increased with age, which may explain previously reported age‐associated increases in cardiac stiffness. SPARC deletion blunted the age changes observed in collagens I and III and laminin b2. Of interest, fibrillin and elastin showed a significant increase with age in the Null mice, suggestive of increased microfibril deposition in the absence of SPARC. In summary, our data suggest SPARC is a possible therapeutic target for aging induced cardiac dysfunction.Grant Funding Source: Supported by HHSN 268201000036C (N01‐HV‐00244), R01 HL075360, HL051971, 1SC2 HL101430, 5I01BX000505
Disrupted gene expression in human cerebral cavernous malformations (1123.3)
Authors: Shishoian Taline , Stockton Rebecca 
Published: June 2021

CCM is a serious human disease affecting 35 million people worldwide, characterized by grossly dilated brain capillaries forming clustered caverns. CCM is caused by familial (inheritable) mutations in KRIT1, CCM2 or PDCD10 genes, or sporadic occurrence of unknown origin. Hemorrhagic stroke may occur and symptomatic lesions are removed surgically since no drug therapy exists. All three CCM genes are expressed in all tissues, so inherited mutations might be expected to produce vascular lesions everywhere. Instead CCMs are confined to the brain, suggesting there are brain capillary‐specific additional genetic disruptions contributing to CCM pathology. My project focuses on assessing expression of target genes in CCM endothelial cells to identify commonly deregulated genes in both familial and sporadic CCMs. I purified RNA from resected human tissue, then performed Reverse‐Transcription PCR to synthesize a cDNA library representing differential expression between sample and control normal endothelial cells. We conducted gene expression studies first by microarray to identify target genes, then validation using quantitative PCR (qPCR) to compare normal and diseased tissue, to determine statistically significant changes in CCM samples. We find disruptions in functional GO cluster groups including apoptosis and matrix synthesis.Grant Funding Source: NIH