bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of proteases and changes in Na+‐K+ ATPase subunits in hearts subjected to ischemia‐reperfusion
Authors: Müller Alison L , Freed Darren H , Dhalla Naranjan S 
Published: June 2021

ObjectiveTo evaluate the role of proteases in sarcolemmal Na+‐ K+ ATPase subunits and activity these ischemia‐reperfusion (I/R) injury by subjecting rat hearts to different times of global ischemia and reperfusion.MethodsGlobal ischemia was induced in rat hearts for 15, 30, and 60 minutes. I/R injury was performed by reperfusing hearts for 5, 10, 20, and 40 minutes after ischemia. Extent of degradation of Na+‐K+ ATPase subunits, α‐1, α‐2, β‐1, and β‐2 was measured in addition to activity assays for Na+‐K+ ATPase, calpain, and MMP‐ 2. Hearts were also perfused with MDL28170 or doxycycline to inhibit calpain or matrix metalloproteinase (MMP)‐2, respectively.ResultsGlobal ischemia depressed protein content of β‐1 and β‐2 subunits and activity of Na+‐K+ ATPase which was accompanied by augmented activities of both calpain and (MMPs) and depressed protein content of β‐1 and β‐2 subunits. Calpain and MMP‐2 activities increased whereas activity and protein content for Na+‐K+ ATPase subunits decreased upon reperfusion. MDL28170 was more effective in attenuating the I/R‐induced alterations in cardiac contracture, Na+‐K+‐ATPase activity than doxycycline.ConclusionsThese results show that activation of both calpain and MMP‐2 are involved in depressing Na+‐K+ ATPase activity and degradation of its subunits directly or indirectly in hearts subjected to I/R injury.FundingManitoba Health Research Council.
Methyl group partitioning during insufficient and excess availability via guanidinoacetate and creatine supplementation in young pigs
Authors: McBreairty Laura Emily , Robinson Jason L , Brunton Janet A , Bertolo Robert F 
Published: June 2021

Methionine is an essential amino acid that provides methyl groups for transmethylation (TM) reactions via S‐adenosylmethionine (SAM), resulting in S‐adenosylhomocysteine (SAH), an inhibitor of TM reactions. Methylation of guanidinoacetate (GAA) to produce creatine (Cr) is proportional to GAA availability while Cr supplementation reduces GAA production and spares methyl groups. Our objective was to determine the partitioning of methyl groups among TM reactions under conditions of excess and insufficient methyl group availability. Three mo‐old pigs (n=18) were fed control, GAA‐ or Cr‐supplemented diets twice daily. On day 18, anesthesia was induced 1–3 h post feeding and a bolus of [methyl‐3H]methionine was intravenously infused. After 30 min, the liver was analyzed for methyl‐3H incorporation into protein, Cr, phosphatidylcholine (PC) and DNA. Compared to control (P<0.05), Cr and GAA led to a 200% and 700% increase in hepatic Cr concentration, respectively; GAA caused a 400% increase in total hepatic Cr methyl‐3H incorporation. Unlike Cr pigs, GAA supplementation decreased methyl‐3H incorporation into PC and decreased hepatic SAM concentration with no change in SAH, suggesting that creatine synthesis resulted in a limited methyl supply for PC synthesis (P<0.05). Creatine supplementation did not spare methyl groups, but GAA did lead to a limited methyl supply (CIHR).Grant Funding Source: CIHR
Mechanical Tissue Resuscitation (MTR) activates the RISK pathway and widens the therapeutic window for treating acute myocardial infarction
Authors: Jordan James E. , Pereira Beatriz D. , Morykwas Michael J. , Lane Magan R. , Mays Jennifer J. , Colmer Gerard , Hollingsworth Charlotte , Argenta Louis C. 
Published: June 2021

BackgroundReperfusion injury results in the continued loss of myocardial cells following revascularization of ischemic myocardium. Therapeutics which decrease myocardial cell death may improve the morbidity and mortality associated with AMI. MTR has been demonstrated to reduce infarct size when initiated at the time of reperfusion. Here we hypothesize that this therapeutic approach remains efficacious even when the initiated further into reperfusion.MethodsA left, anterior free‐wall ischemic lesion (85 min.) was created using reversible tourniquets in swine. Animals were randomized to receive either no treatment (Control) or MTR (−125 mmHg) beginning 90 min. after reperfusion. Following reperfusion, infarct size (IS), PMN accumulation and activation of the RISK salvage pathway were assessed.ResultsMTR reduced IS (24.2±4.8% vs. 50.3±2.7%, AN/AAR, p< 0.001) with no difference in the AAR (p=0.88). PMN accumulation within the AAR was also reduced by MTR (19.7±2.5 vs. 28.9±4.9 units). MTR increased the phosphorylation of ERK1/2 and AKT in epicardial tissue 2.1‐fold (p<0.01) and 2.0‐ fold (p=0.06), respectively.ConclusionsMTR provides robust protection from MI/R injury by activating the RISK pathway even when initiated 90 min. into reperfusion. This timing defines a clinically relevant window of opportunity for the treatment of MI/R injury and potentially expands the patient population who could derive benefit from such therapeutic intervention.
Activation of formyl peptide receptors induces relaxation and reduces contraction in resistance arteries
Authors: Wenceslau Camilla Ferreira , McCarthy Cameron G. , Goulopoulou Styliani , Webb R. Clinton 
Published: June 2021

Mitochondrial damage‐associated molecular patterns (DAMPs) are endogenous molecules that are released from damaged and dying cells. The innate immune system responds to cellular damage by recognizing DAMPs. One mitochondrial DAMP is formyl peptides (fMLP) that act on formyl peptide receptors (FPR). FPR 1 and 2 are expressed on neutrophils as well as in vascular cells, and promote inflammatory responses. We hypothesized that activation of both receptors increases vascular contractile response. We used mesenteric resistance arteries from 12 weeks old male Wistar rats to assess vascular function. A single dose of fMLP, FPR‐1 agonist (10 or 30μM) and a concentration response curve of lipoxin A4, FPR‐2 agonist (LXA4, 1–300nM) induced relaxation (~30%). Cyclosporine H (FRP‐1 antagonist: CsH, 1μM) inhibited the fMLP response. Also, concentration response curves to acetylcholine (ACh, 0.1nM‐30μM) and phenylephrine (PE, 1nM‐30μM) were performed in the absence or presence of CsH (1 μM), fMLP (10μM) or LXA4 (1nM). Results indicated that fMLP, but not CsH or LXA4, decreased PE contraction [Emax(%KCl), vehicle: 119±6 vs. fMLP: 96±1, p<0.05], however ACh‐induced relaxation was not altered. These data suggest that FPRs have a functional role in resistance arteries and may contribute to vascular dysfunction in pathologies associated with tissue damage such as sepsis or hypertension.Support: NIH; CNPq; SWHR
Novel Rap1‐dependent regulator of endothelial cell junctions afadin mediates protective effects by oxidized phospholipids in the models of acute lung injury
Authors: Birukov Konstantin G , Sarich Nicolene , Dubrovskyi Oleksii , Zebda Noureddine 
Published: June 2021

Afadin has been described as a regulator of epithelial cell junctions assembly. However, its role in control of vascular permeability remains obscure. We have previously described protective effects of oxidized phospohlipids (OxPL). This study examined a role of afadin and its upstream regulator Rap1 GTPase in the OxPL‐induced cell junction assembly as a novel mechanism of endothelial cell barrier preservation. OxPL induced Rap1‐ dependent afadin translocation to the cell periphery and promoted accumulation of adherens junction and tight junction proteins at the cell membrane. OxPL also stimulated Rap1‐dependent afadin interactions with adherens junction and tight junction proteins p120‐catenin and ZO‐1, respectively. SiRNA‐induced knockdown of afadin or Rap1 suppressed endothelial barrier enhancement caused by OxPL and abolished barrier protective effects of OxPL against thrombin‐induced endothelial permeability. Similar effects were obtained in experiments with ectopic expression of afadin mutant lacking Rap1 GTPase binding domain or inhibitor of Rap1 activity, Rap1‐GAP. Afadin or Rap1 siRNA‐mediated knockdown also abolished protective effects of OxPL against acute lung injury in vivo. These results demonstrate for the first time a critical role of afadin in the regulation of vascular barrier function in vitro and in vivo.Funding: NHLBI HL76259, HL089257, HL107920
Endurance training promotes upregulation in microRNA‐206 on blood and in human skeletal muscle
Authors: Alves Cleber Rene , Junior Jose Ribeiro Lemos , Alves Guilherme Barreto , Negrão Carlos Eduardo , Oliveira Edilamar Menezes 
Published: June 2021

Skeletal muscle is a highly plastic organ, capable of altering phenotype in response endurance training (ET). MicroRNAs (miR) are a class of short, non‐coding RNA molecules that reportedly play a central role in regulating post‐transcriptional. Therefore, we evaluated the effects of ET on the blood and in human skeletal muscle in miRNAs‐206 levels.Twelve healthy volunteers were biopsied in vastus lateralis muscle and collected blood sample. Heart rate (HR), mean blood pressure (MBP), maximal exercise capacity (VO2peak), forearm blood flow (FBF) and forearm vascular conductance (FVC) were evaluated. MiR 206 levels were analyzed by real‐time PCR. Endurance training was performed for 16 weeks. After ET, the individuals showed an increase of 97% in skeletal muscle and 128% on blood in miR 206 levels. These alterations were accompanied by decreased in resting bradycardia (12,5%), increased of VO2peak (18%), FBF (68%) and FVC (63%).These results show that in healthy subjects the miR‐206 expression is up regulated after endurance training paralleled with improved of vascular function and endurance capacity, suggesting miR‐206 may have a role on metabolism related with high performance.
Endurance training changes the DNA methylation pattern in human skeletal muscle
Authors: Lindholm Malene Elin , Marabita Francesco , Gomez‐Cabrero David , Fischer Heléne , Tegnér Jesper , Sundberg Carl Johan 
Published: June 2021

Long‐term endurance training induces many beneficial effects in human skeletal muscle. However, some people respond strongly while others barely improve. Training responsiveness is related to differential gene expression through incompletely understood mechanisms. We hypothesized that DNA methylation pattern changes with endurance training and that these changes could be related to training response.17 subjects (males and females) performed three months of supervised one‐legged knee extension endurance training. DNA from vastus lateralis muscle biopsies was used for an Illumina 450K chip. Training response was evaluated using one‐legged performance tests and enzyme activity assays.The Illumina data showed around 5000 sites that significantly changed in methylation level with training. Using methylation estimates for these sites, two responder groups were identified with different magnitude of change in citrate synthase activity. It was also possible to separate the males and females based on methylation level of these sites (excluding the sex chromosomes), a finding of great interest for the difference between male and female skeletal muscle.In conclusion, our results indicate that DNA methylation is affected by endurance training and could be one mechanism involved in the variability in response.
Elevated peripheral blood mononuclear cell‐derived superoxide production in healthy young black men
Authors: Deo Shekhar H , Holwerda Seth W , Keller David M , Fadel Paul J 
Published: June 2021

Several studies have demonstrated that blacks exhibit elevations in plasma oxidative stress. However, the sources and mechanisms contributing to the elevation in oxidative stress remain unclear. Given recent work indicating that peripheral blood mononuclear cells (PBMCs) can be a major source of angiotensin II type 1 receptor (AT1R)‐NADPH oxidase derived superoxide production, we sought to examine this pathway in mediating the increase in systemic oxidative stress in black men. PBMCs were isolated from whole blood in 8 black and 8 age‐matched white men. Intracellular superoxide production was measured using dihydroethidium fluorescence and protein expression of AT1R and NADPH oxidase subunit, gp91phox were assessed using western blot. Black men showed elevated resting intracellular superoxide production (7.5±1.7 blacks vs. 3.1±1.1 whites, RFU; P<0.05) as well as protein expression for AT1R and gp91phox (P<0.05 vs. whites). Furthermore, for all subjects, AT1R expression was related to gp91phox (R = 0.67; P<0.05). These preliminary findings suggest that young black men exhibit greater resting PBMC derived superoxide production potentially via an up‐regulation of the AT1R‐NADPH oxidase pathway.Supported by NIH Grant R15HL096103 (DMK) and RO1 HL093167 (PJF)
Inspiratory Muscle Exercise Reduces Lipoperoxidation in Obese and Healthy Subjects: A Pilot Study
Authors: Callegaro Carine Cristina , Maldaner Loani , Donato Letícia , Spring Amanda , Porto Fernando , Chaves Leandro , Cattaneo Roberta 
Published: June 2021

IntroductionHigh‐intensity inspiratory exercise seems to increase oxidative stress in healthy subjects. Although obesity is related to impaired inspiratory muscle function, the acute effects of the inspiratory exercise remain unclear in obese subjects.MethodsWe studied 10 obese (35 ± 3 kg/m2; 32 ± 6 years old) and 10 healthy subjects (23 ± 2 kg/m2; 24 ± 5 years old). Maximal inspiratory pressure (PImax) was assessed by a pressure transducer. Blood sample was collected to assess thiobarbituric acid reactive substances (T‐BARS) before and after the inspiratory exercise performed in different days to inspiratory exercise without load maintained for 30 min, inspiratory exercise at 30% PImax maintained for 30 min and inspiratory exercise at 60% PImax maintained until reach the fatigue.ResultsInspiratory muscle strength was similar in obese and healthy subjects. Inspiratory exercise performed at 60% PImax reduced T‐BARS in obese (from 6 ± 2 nmol MDA/mL to 4 ± 2 nmol MDA/mL) and in healthy subjects (from 7 ± 4 nmol MDA/mL to 5 ± 3 nmol MDA/mL, ANOVA: Time= 0,003; Group= 0,52; Interaction= 0,98). As expected, inspiratory exercise performed without load and at 30% PImax did not change T‐BARS in obese and healthy subjects.ConclusionThis study shows that acute inspiratory exercise may reduce lipoperoxidation in humans.
Impact of Augmenting Intracellular ATP on the Inducible Release of ATP from Banked Erythrocytes
Authors: Kirby Brett S , Zhu Hongmei , Riccio Daniel A , McMahon Timothy J 
Published: June 2021

Prolonged banking of human erythrocytes (RBCs) coincides with adverse clinical outcomes following blood transfusion. Healthy RBCs release ATP that is vasoactive and anti‐adhesive, but hypoxia‐induced release of ATP from banked RBCs is markedly impaired. We tested the hypothesis that stored RBCs (35–42 days in blood bank) demonstrate impairments in ATP release that are common among disparate stimuli, and that release can be improved with an intracellular ATP ([ATP] i) boosting solution (Rejuvesol). ATP release from human RBCs (fresh or stored) was measured after mechanical deformation (5μm filtration) or direct G‐protein activation (mastoparan7; Mas7). Average basal ATP release was 146±19 and 107±14 nM from fresh and stored RBCs, respectively. Deformation‐induced release from stored RBCs was blunted compared to fresh (Δ34 vs 180%), but similar from Mas7 (Δ78 vs 95%). [ATP] i was lower in stored vs fresh RBCs, but elevated by Rejuvesol (2.8 vs 4.8 vs 6.8 umol/g Hb). Augmenting [ATP] i increased ATP release upon deformation by 2‐fold, but had no impact on Mas7‐induced release. These data suggest a specific impairment in inducible ATP release from stored human RBCs that is upstream of G‐protein coupled receptor activation, and that augmenting [ATP] i may improve ATP release in response to deformation. Improved ATP export may in turn support better clinical outcomes following RBC transfusion.Support NIH HL113943
Intestinal epithelial endocytosis of commensal bacteria is dependent on IFNγ‐induced terminal web myosin phosphorylation and brush border fanning
Authors: Wu Li‐Ling , Kuo Wei‐Ting , Peng Wei‐Hao , Lu Kuo‐Shyan , Ni Yen‐Hsuan , Yu Linda Chia‐Hui 
Published: June 2021

Bacterial dissemination is commonly seen in intestinal obstruction (IO). Paracellular influx was mediated by ROCK signaling for phosphorylated myosin light chain (pMLC) and tight junctional disruption. Myosin phosphorylation in terminal web (TW) is associated with brush border (BB) fanning. The mechanism of bacterial endocytosis in enterocytes remains unclear.AimTo investigate the role of IFNγ in TW pMLC for bacterial endocytosis.MethodsMouse intestines were obstructed by loop ligation in which inhibitors were luminally administered. Next, mice were injected i.p. with anti‐IFNγ. Bacterial endocytosis in isolated enterocytes was measured by gentamycin resistance assay and fluorescence in situ hybridization. Epithelial Ca2+/ATP‐dependent TW contraction and BB fanning were visualized using TEM.ResultsBacterial endocytosis was observed without paracellular permeability change at 3–6 h of IO. Enterocytic pMLC localized to TW was associated with BB fanning, which may be inhibited by ML‐7 but not Y27632. IO‐induced bacterial endocytosis through intermicrovillus space was reduced by ML‐7 or anti‐IFNγ. Caco‐2 cells treated with IFNγ showed MLCK‐dependent TW contraction and E. coli endocytosis and translocation.ConclusionsIFNγ‐induced epithelial MLCK‐dependent TW contraction and BB fanning is involved in bacterial endocytosis. Funding support by National Science Council and NTU.
Effect of Hypovitaminosis D on Muscle Function and Physical Performance in Saudi Women‐Cross sectional
Authors: Hussein Khulood Sami 
Published: June 2021

INTRODUCTION AND AIMSVitamin D deficiency is associated with reduced muscle strength. Data on the effect of poor vitamin D status on physical performance in Saudi women are lacking. The aim of this study was to investigate the correlation between vitamin D level and measures of physical performance.METHODSA total of 223 postmenopausal [>;51 years] healthy women were randomly recruited. Fasting blood samples were collected for assessment of 25(OH)D status. Muscle function was assessed by the time taken to perform the following tests: get up and go (GUG); 8 feet walk (8FW); five‐times sit to stand (5‐STS). SPSS (version 16) was used for data analysis.RESULTS & DISCUSSION39% of women were < 25nmol/L, 77% < 50 nmol/L, and 95% < 75 nmol/L. A significant negative correlation was found between 25(OH)D and GUG (P<0.05). After adjusting for key confounding factors including BMI the correlation disappeared. Linear regression analysis was used to examine the association between vitamin D level and measures of physical performance adjusting for potential confounders. Vitamin D level was not among the predictors of physical performance measures in this study group.CONCLUSIONThese data suggest that low vitamin D status is not associated with poor physical performance and may be a reflection of muscle adaptation to prolonged, life‐cycle of hypovitaminosis D.
Stereological analysis of Akt in muscles of young and old rats following a single bout of stretch‐shortening contractions
Authors: Rader Erik P , Ensey James , Baker Brent A 
Published: June 2021

Careful design of resistance training programs is critical for offsetting age‐related sarcopenia. To address this, we implemented a non‐injurious stretch‐shortening contraction (SSC) protocol to muscles of rats. Following 4.5 weeks of resistance‐type training, muscles of young rats increased force by ~30% and mass by ~16%, while old rats sustained force deficits of ~30% with no change in muscle mass; no overt signs of histopathology were noted. Age‐related maladaptation to training may be due to aberrant Akt signaling – signaling influential in cellular survival/growth.PurposeTo characterize volume density of Akt positive muscle fibers following an acute bout of non‐injurious SSCs with aging.MethodsDorsiflexor muscles of 12wk. and 30mo. old Fischer 344xBN Hybrid rats were exposed to SSCs in vivo. At 6h, 3d, and 5d, tibialis anterior muscles were removed for stereological analysis of transverse sections labeled for pan‐Akt (N =3 per group).ResultsFor control muscles and muscles at 6h, pan‐Akt volume density represented ~40% of total tissue volume and was independent of age. At 3d and 5d post SSC, pan‐Akt levels were unaltered for old rats while values for young rats were decreased relative to values for old (p<0.05).ConclusionWhile the training‐induced decrease in Akt at young age needs further study, the lack of change in Akt levels at old age is consistent with an overall blunted response to training.
Multivalent GLP‐1/Yhb for targeted therapy and imaging of pancreatic β‐cells
Authors: Ananthakrishnan Kameswari , Penrod Leah V. , Hart Nathaniel J. , Weber Craig S. , Anderson Miranda , Vagner Josef , Limesand Sean W. , Lynch Ronald M. 
Published: June 2021

Glucagon like peptide‐1 (GLP‐1) has potential for treating diabetes due to its effects on β‐cell proliferation and function. Described is a GLP‐1 analog that targets β‐cells specifically, which may increase its therapeutic efficacy and make it useful for monitoring β‐cell mass. GLP‐1 was coupled with a flexible linker to Yohimbine (Yhb) (α2 Adrenergic Receptor antagonist). GLP‐1/Yhb binds to cells expressing both receptors at low nM concentrations and is rapidly internalized. In cells where either GLP‐1R or α2AR were knocked down, binding of GLP‐1/Yhb was severely impaired (≤ half of control cells) indicating both receptors are required for high affinity binding. Intravenous injection of 250nM GLP‐1/Yhb‐Cy5 showed a high β‐cell:acinar ratio of ~1.8:1 in pancreatic sections while binding of 111In‐labeled GLP‐1/Yhb in isolated rat islets was significantly higher than acinar cells. Only islet binding was blocked by unlabeled GLP‐1/Yhb indicating specific binding. Following tail vein injection of 111In‐GLP‐1/Yhb, >; 90% of ligand was cleared from circulation within 30 mins. At this time, specific binding in pancreas relative to a range of other tissues was observed because pretreatment with cold GLP‐1/Yhb blocked only islet binding. In all, these data show that GLP‐1/Yhb binds selectively to β‐cells, demonstrating its potential for targeted β‐cell imaging and therapy.Support: Juvenile Diabetes Research Fnd
Effects of the Momordica charantia (MC) in the alterations caused by administration of a high fat diet (HL) as a model of non‐alcoholic fatty liver disease (NAFLD)
Authors: Santos Maria Emilia Soares Martins , Lemos Bruno Silva Oliveira , Teixeira Keyt Braz , Silva Lilian Nayra , Souza Geovana Alves , Pinto Flávia Carmo Horta , dos Santos Lima Luciana Alves Ribeiro , Santos Maria Emilia Soares Martins 
Published: June 2021

The aim of this work was to study the effects of MC on metabolism from NAFLD animals. Mice received a control (C) or a HL diet/8 weeks. One HL group was administered with MC extract/5days (HLT5) after the diet period. Other HL group received MC tea (HLTT) instead of water at the same period of diet. Blood was collected for analysis of glucose (GLU), cholesterol (CTO), high density lipoprotein (HDL), triacylglycerol (TAG), alanine aminotransferase (ALT) and very low density lipoprotein (VLDL). Liver was removed for histology. HL showed an increase in body weight (35.0 ±0.8 vs 48.3 ±1.0), liver weight (C 1.7 ±0.07 vs HL 2.6 ±0.01), GLU (562.1±13.4 vs 701.8 ±20.1), ALT (57.3 ±6.4 vs 105.1 ±6.1), CTO (145.8 ±9.9 vs 195.2±14.9), HDL (107.7± 0.6 vs 171.9 ±8.7), VLDL (21.5 ±1.54 vs 34.8 ± 6.8) and TAG (75.0 ±6.6 vs 171.5±34.4) in comparison to C. MC extract administration decreased: GLU (701.8 ±20.1 vs 306.7 ±31.0), CTO (195.2 ±14.9 vs 103.6 ±4.6), VLDL (34.8 ± 6.8 vs 8.6 ± 0.5), HDL (171.9 ±8.7 vs 97.1 ±7.8), TAG (171.5 ±34.4 vs 43.4 ± 2.6), liver weight (2.6 ±0,01 vs 1.7 ±0.13). HLTT animals decreased: GLI (661.8±26.2 vs. 528.5±57.9), VLDL (37.5±4.142 vs. 9.7±1.1) and TAG (174.07±16.71 vs. 48.9±5.64) in comparison to HL. Significant improvement was observed histologically in liver from animals with NAFLD when they received MC. MC seems to be efficient in treatment/preventing hyperglycemia, hyperlipidemia and NAFLD.Financial support: CNPq