bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fructooligosaccharides (FOS) enhance beneficial effects of a flavonoid, quercetin‐3‐glucoside (Q3G), on insulin sensitivity in rats fed high sucrose diet
Authors: Phuwamongkolwiwat Panchita , Suzuki Takuya , Hira Tohru , Hara Hiroshi 
Published: June 2021

An enhancement FOS on improvement of glucose tolerance and insulin sensitivity by a flavonoid glycoside, Q3G, and their mechanisms were studied. Rats were fed a sucrose‐based diet with or without 0.3% Q3G, 5% FOS, or 0.3% Q3G+5% FOS, while dextrin‐based diet was used for a normal reference group. OGTTs were conducted on day 14, 28, 45. Flavonoid levels in the aortic blood were measured by LC/MS. Body weight gain was lowered in Q3G+FOS group without changes in food intake. Abdominal fat weights and cecal pH were reduced in both the FOS‐fed groups without any effects of Q3G. Combination of Q3G and FOS only reduced blood glucose levels at 60 min in all OGTTs. HOMA‐IR showed an improvement in the Q3G+FOS group on day 14 and 28. On day 45, the value was improved in the individual FOS or Q3G group, and was further improved in the FOS+Q3G group. A much higher blood level of quercetin was observed in the FOS+Q3G group compared with the Q3G group, which may contribute the combination effects of Q3G and FOS. Secretion of GLP‐1 observed in the small intestinal loops of anesthetized rats and in vivo experiment were increased by addition of quercetin to luminal fluid containing FOS. This may involve in the improvement of glucose tolerance. In conclusion, FOS increases bioavailability of Q3G, and enhanced beneficial effects of Q3G on glucose tolerance and insulin sensitivity, which have a potential for prevention of type 2 diabetes.Grant Funding Source : Graduate School of Agriculture, Hokkaido University
PH‐427 reduces the survival of fat‐treated pancreatic cancer cells
Authors: Cantoria Mary Jo Castro , Meuillet Emmanuelle 
Published: June 2021

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and lethal cancer. A large number of epidemiological studies have linked type‐2 diabetes, obesity and metabolic syndrome, characterized by insulin resistance with an increased risk for developing PDAC. The IGF‐IR/PI3K/AKT survival pathway has been suggested to be the major signaling pathway involved in these processes. Indeed, AKT is a key signaling pathway in PDAC as it mediates cancer cell survival and proliferation. We have developed the AKT Pleckstrin Homology (PH) domain inhibitor, PH‐427, which prevents AKT activation and possess anti‐tumor activities in vivo models of pancreatic cancer. Hence, the objectives of this study were 1) to develop a cellular model for obesity‐driven pancreatic cancer and 2) to determine the effects of PH‐427 on cell viability of pancreatic cancer cells exposed to a fatty environment. BxPC3 cells were incubated in RPMI media supplemented with cholesteryl hemisuccinate (CHS) for two weeks. We show that CHS induced an insulin resistance state whereby AKT phosphorylation is reduced upon IGF‐I stimulation as compared to control cells. Moreover, MTT assays indicated that CHS‐treated cells were more sensitive to PH‐427 treatment as compared to control cells (IC50= 10.9±3.7 versus 15.2±1.5□M). These preliminary data suggest the promising potential use of this novel drug for the treatment of obesity‐induced PDAC.Grant Funding Source : None
Resveratrol decreases inflammation and oxidative stress in the mdx mouse model of duchenne muscular dystrophy
Authors: Gordon Bradley Scott , Weed Patti , Learner Emily , Schoenling Drew , Kostek Matthew C 
Published: June 2021

Duchenne Muscular Dystrophy (DMD) is a genetic disease characterized by muscle damage, oxidative stress, chronic inflammation, and fibrosis. Resveratrol (RES) is an antioxidant and anti‐inflammatory. We have shown that RES improves muscle function in the mdx mouse model of DMD, and others have shown resveratrol decreases fibrosis and oxidative stress in older mdx mice. However, its effect on pathology in young mdx mice is unknown. The purpose of this study was to investigate the effect of resveratrol on muscle pathology in young mdx mice. RES (100 mg/kg) or vehicle was administered to 4–5 week old mdx mice everyday for 10 days or every other day for 8 weeks. Muscle fiber integrity, inflammation, and oxidative stress were assessed by H&E staining and 4‐HNE content. Total inflammation was reduced 21 ± 6% (p < 0.05) after 10 days of treatment with no change in oxidative stress. After 8 weeks of RES treatment, centrally located nuclei were reduced 12 ± 4% (p < 0.05), oxidative stress measured through 4‐HNE content decreased 2 ± 0.13 fold (p < 0.05), and total inflammation and fibrosis did not change. We conclude that RES enhances muscle membrane integrity by reducing inflammation during the peak pathological period and long term oxidative stress. Therefore, resveratrol could be a treatment for boys with DMD. This project was funded by The Center for Alternative Medicine at The University of South Carolina School of Medicine.Grant Funding Source : Center of Alternative Medicine University of South Carolina School of Medicine
Effect of Dabigatran and Rivaroxaban on thrombomodulin mediated activation of protein C and thrombin activated fibrinolysis inhibitor (TAFI)
Authors: Fareed Jawed , Hoppensteadt Debra , Cunanan Josephine , Lewis Bruce 
Published: June 2021

IntroductionThe new oral anticoagulant agents Dabigatran and Rivaroxaban target thrombin and factor Xa to mediate their anticoagulant effects perspectively. This study was designed to investigate the effects of active form Dabigatran and Rivaroxaban on the activation process of protein C and TAFI by thrombin‐thrombomodulin complex.Materials and MethodsThe active form of Dabigatran was synthesized. While Rivaroxaban was extracted from commercially available tablets. Both agents were dissolved in appropriate solution matrices at a stock concentration of 100ug/ml. Thrombin‐thrombomodulin mediated activation of protein C and TAFI were measured using specific chromogenic substrate based methods at a concentration of 0–10ug/ml in different matrices.ResultsDabigatran produced a strong inhibition of the generation of both the activated protein C and TAFI (IC50<1.0ug/ml) whereas Rivaroxaban did not produce any inhibition of the activation of either of these proteases. Dabigatran also inhibited the amidolytic actions of thrombin‐thrombomodulin complex whereas Rivaroxaban did not produce any effect. Neither Dabigatran nor Rivaroxaban produced a direct inhibition of activated protein C or TAFI at concentrations of up to 10ug/ml.ConclusionsThe persistent inhibition of thrombin and its regulatory effects by Dabigatran may differentiate its pharmacologic profile from Rivaroxaban.
High Affinity Binding of Dynorphin A‐(2–13) at the Bradykinin‐2 Receptor
Authors: Hall Sara Michelle , Rankin David R. , Cai Alice , Hruby Victor J. , Lee Yeon Sun , Lai Josephine 
Published: June 2021

Experimental evidence has shown that dynorphin A can interact with bradykinin receptors to activate calcium influx through a non‐opioid mechanism. The apparent affinity and potency of the non‐opioid fragment, dynorphin A‐(2–13), at the bradykinin‐2 receptor (B2R) were moderate (Ki ~ 1 μM and EC50 ~ 500 nM). This suggests that the interaction of dynorphin A and its proteolytic fragments with the B2R may be physiologically relevant only during up regulation of endogenous dynorphin A. Here we report that dynorphin A's interaction with the B2R is surprisingly sensitive to pH within a narrow physiological range.Competitive binding against [3H]kallidin showed the highest affinity of dynorphin A‐(2–13) at pH 6.8 (5 fold, and 100 fold higher than that at pH 7.4 and pH > 7.4, respectively). The pH sensitivity likely contributed to an initial underestimation of dynorphin's affinity at the receptor. Also the distinct structure‐activity relationship of dynorphin A analogs suggest that dynorphin A can interact with bradykinin receptors specifically and with high affinity. Its higher affinity for B2R at lower pH may have relevance in chronic inflammatory pain.This study is supported by NIH grant P01 DA 006248.
Arginase 1 as a Therapeutic Target in Diabetic Retinopathy
Authors: Elms Shawn Christopher , Flores-Toque Haroldo , Caldwell R William , Caldwell Ruth 
Published: June 2021

ObjectiveIschemic injury is a prominent feature of diabetic retinopathy (DR), but the underlying molecular mechanisms are not understood. In healthy individuals, nitric oxide (NO) produced by NO synthase (NOS) maintains normal blood flow. The urea cycle enzyme arginase (Arg) can limit NO formation by competing for L‐arginine, a substrate for both enzymes. Our objective is to investigate the role of Arg in diabetes‐induced retinal vascular dysfunction.MethodUsing a novel mouse funduscope capable of imaging the retinal microcirculation, we examined the role of Arg expression/activity in STZ diabetes‐ induced retinal vascular dysfunction.ResultsOur studies showed that endothelial dependent vasorelaxation is markedly impaired in arterioles of STZ diabetic mice (60% of control) as Arg activity and expression are increased. The vascular dysfunction is largely prevented in Arg I+/− mice (85% of control) or mice treated with the specific Arg inhibitor ABH, thus indicating Arg as a mediator of diabetes‐induced decreases in endothelial dependent vasorelaxation.ConclusionOur data indicate that increases in Arg protein/activity are involved in diabetes‐induced retinal vascular dysfunction. Using this novel imaging technology to measure vascular function in vivo in conjunction with arginase inhibitors offers a novel methodology for pharmacological research on retinal microvascular disease.
Mechanistic and pharmacologic role of placental growth factor in experimental ulcerative colitis in rats
Authors: Deng Xiaoming , Xiong Ximing , Khomenko Tetyana , Chen Longchuan , Szabo Sandor , Sandor Zsuzsanna 
Published: June 2021

We demonstrated that vascular endothelial growth factor accelerated the healing of experimental duodenal ulcer but aggravated ulcerative colitis (UC), probably because of the differences in ulcer healing. Since placental growth factor (PlGF) enhances abnormal (“pathologic”) angiogenesis, we measured its expression and role in experimental UC. Groups of rats were given iodoacetamide (IA) to cause UC and they were euthanized at 0.5, 2, 6, 12, 24, 48, and 84 hr after IA. Additional groups of rats were given neutralizing anti‐PlGF antibody, IgG (50ug/rat, i.m.) or saline on 2nd and 5th days and euthanized 7th day after IA when the extent of UC was evaluated macroscopically and by microscopy. Mucosal scrapings of distal colon were obtained at autopsy. Expression of PlGF was measured by Western blotting.ResultsExpression of PlGF protein was enhanced at 2 hr, with further increases (+50–80%) until 7 days. Inhibition of PlGF significantly reduced the levels of colonic PlGF, i.e., 2‐ to 3‐folds compared to control. Colonic lesions were also decreased from 323.2±44.1 (controls) to 209.8±31.2 mm2 (anti‐PlGF) (p < 0.05).Conclusions1) The sustained increase in expression of PlGF in UC may indicate an abnormal (pathologic) angiogenesis occurring in the development of UC. 2) Inhibition of PlGF attenuated experimental UC development. 3) Thus, PlGF may play a pathogenic & therapeutic role in the development & healing of UC.(This work was supported by the Veterans Health Administration Merit Review Grants to Zs. Sandor and S. Szabo)
CGRP released from perivascular sensory nerves down‐regulates NO signaling through activation of pannexin‐based hemichannels in mesenteric resistance arteries
Authors: Gaete Pablo Simón , Lillo Mauricio , Pérez Francisco , Figueroa Xavier 
Published: June 2021

It is thought that sensory nerve fibers contribute to the control of vasomotor tone by the release of calcitonin gene‐related peptide (CGRP). We stimulated the isolated rat arterial mesenteric bed with 1μM capsaicin or 100nM CGRP for 20 min and assessed the changes in nitric oxide (NO) signaling and hemichannel activity. Hemichannel activity was evaluated by ethidium or Lucifer Yellow (LY) uptake, expression and phosphorylation of eNOS by Western blot and NO‐dependent vasodilation with acetylcholine (ACh). Mesenteric arteries did not show detectable hemichannel activity in control conditions, but stimulation with either capsaicin or CGRP induced a robust ethidium or LY uptake that was maintained for >1 hr and was inhibited by probenecid, a pannexin hemichannel blocker. Capsaicin treatment induced a decrease in eNOS expression and eNOS phosphorylation at serine 1177 that reached significance 1–3 hrs after stimulation. Accordingly, the NO‐dependent ACh‐induced vasodilation was abolished 1 hr after capsaicin application, which was prevented by treatment with probenecid. These results suggest that CGRP release from capsaicin‐sensitive sensory nerves induces a prolonged activation of pannexin‐based hemichannels in endothelial cells, which leads to a reduction in NO signaling in mesenteric resistance arteries.FONDECYT 1100850, FONDECYT 1090757, FONDECYT 1111033, Anillos ACT‐71
Agmatine‐mediated Arterial Relaxation is impaired in Salt‐Sensitive Hypertension
Authors: Gadkari Tushar , Cortes Natalie , Tsoukias Nikolaos , Joshi Mahesh 
Published: June 2021

BackgroundWe have shown that agmatine may initiate signal transduction by NO synthesis via α‐2 AR binding. Since NO activity is compromised in hypertension, we investigate whether agmatine mediated relaxation is perturbed in hypertension.MethodsSix week old Dahl rats separated in two diet groups (0.49% NaCl and 4% NaCl) developed hypertension after 11 weeks on high salt. Isolated, cannulated, pressurized 2nd order mesenteric arterioles were preconstricted to norepinephrine in a vessel chamber at 37°C. Vascular reactivity to agmatine was tracked in real time on inverted microscope. mRNA was isolated and RT‐PCR expression of α‐2A‐AR, α‐2B‐AR and eNOS was carried out.Results and ConclusionIn normotensive Dahl rats, the vessel in response to agmatine attaining a maximal relaxation of 90.41±1.69 % with an EC50 of 107.69±13.54 μM (n=3). However, in hypertensive Dahl rats, these relaxations were significantly compromised with maximal relaxation of 19.76±2.44 % (n=3) and EC50 was undeterminable. In RT‐PCR, the mRNA levels of eNOS, α‐2A‐AR, and α‐2B‐AR were significantly lower in high‐salt samples. Agmatine‐initiated relaxation is compromised in hypertension. This work was supported in part by NIH grant SC1HL095101
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Shedding of the Endothelial Glycocalyx and the Resistance to Flow in Capillaries
Authors: Lipowsky Herbert H , Gao Lujia , Lescanic Anne 
Published: June 2021

The endothelial glycocalyx serves as a barrier to transvascular exchange of fluid, macromolecules, and leukocyte‐endothelium (EC) adhesion during the inflammatory process. Shedding of glycosaminoglycans and proteoglycans of the glycocalyx occur in response to several agonists. To elucidate the hemodynamic effects of glycan shedding on capillary resistance to flow during inflammation, intestinal mesentery (rat) was superfused with 10−7 M fMLP. Shedding was quantified by reductions of fluorescently labeled lectin (BS‐1) bound to the EC and reductions in thickness of the barrier to infiltration of 70 kDa dextran (Dx70) on the EC surface. Red cell velocities (two‐slit technique), pressure drops (dual servo‐null method), and capillary hematocrit (direct cell counting) were measured in parallel experiments. Glycocalyx thickness decreased by 80 nm. Capillary resistance rose 18% due to diminished deformability of activated WBCs and fell significantly 26% over a 30 min period, as glycans were shed from the EC surface to increase effective capillary diameter while capillary hematocrit and anatomical diameter remained invariant. This decrease in capillary resistance mitigated the increase in resistance due to diminished WBC deformability and hence these concurrent rheological events may be of equal importance in affecting capillary flow during the inflammatory process.Supported by R01‐HL39286‐20.
ER stress induction increases NADPH oxidase and reduces eNOS activity in endothelial cells
Authors: Galán Maria , Kassan Modar , Alkhafaf Qassim , Trebak Mohamed , Matrougui Khalid 
Published: June 2021

Cardiovascular diseases are associated with endoplasmic reticulum (ER) stress. We have demonstrated that induction of ER stress in C57BL/6J, by the injection of tunicamycin, impairs vascular endothelium‐dependent relaxation (unpublished data).In this study, we aimed to determine the mechanism by which ER stress reduces nitric oxide synthase activity.We incubated mice primary coronary arterioles endothelial cells with tunicamycin (1 ug/mL) for 6 h in the presence or absence of two ER stress inhibitors (Tudca, 500 ug/mL and PBA, 10 mM). Tunycamicin increased the expression of phosphorylated PERK and eIF2alpha, CHOP and ATF6, which were reduced with ER stress inhibitors. The induction of ER stress enhanced NADPH oxidase activity and Nox1/Nox4 mRNA levels associated with an increase of reactive oxygen species, which were reduced by ER stress inhibitors. Phosphorylated eNOS expression was reduced with tunicamycin and rescued by ER stress inhibition. The transfection of endothelial cells with a reporter plasmid containing the eNOS promoter revealed that ER stress induction reduced eNOS promoter activity by 50%, which was rescued by ER stress inhibition.ConclusionER stress enhances oxidative stress and reduces eNOS promoter activity and phosphorylated eNOS, which are responsible for endothelial dysfunction.
Orchidopexy protects the apoptosis of spermatogenic cells in experimentally cryptorchid rats
Authors: Jiang Yuqing , Li Ruili , Guo Yuexian 
Published: June 2021

Orchidopexy is an effective method for patients with cryptorchidism to restitute fertility. To investigate the effects of orchidopexy on the pathogenesis of cryptorchidism, we compared the apoptosis of spermatogenic cells with TUNEL labeling and the expression of Bcl‐2/Bax proteins with immunohistochemistry between orchidopexy and sham groups of cryptorchid rats. We found that the weight of testis was decreased, the apoptotic spermatogenic cells increased, the peak of monokaryotic cells (1C) declined, and the percentage of 1C and 4C reduced, but the percentage of 2C increased after cryptorchidism when compared with sham group. The expression of Bcl‐2 was down‐regulated while Bax was up‐regulated after cryptorchidism. Two weeks after orchidopexy, we found that the number of apoptotic spermatogenic cells was decreased significantly, the expression of Bcl‐2 upregulated, Bax downregulated, and the peak of 1C raised. Six weeks after orchidopexy, there was no significant difference between experimental and sham groups in the weight of testis. The apoptotic spermatogenesis cells were increased but less than those without orchidopexy. The number of 1C increased to the level in sham group. These data suggest that orchidopexy inhibits apoptosis of spermatogenic cells and recovers the spermatogenesis function.Supported by Medical Scientific Research Key Program of Hebei province, China (20100095)
Nesfatin‐1 Alters Synaptic Activity in Neurons in the Nucleus of the Solitary Tract
Authors: Mimee Andrea , Ferguson Alastair V 
Published: June 2021

Nesfatin‐1 (nes‐1) is a recently discovered neuropeptide that decreases food intake and is expressed in the medullary nucleus of the solitary tract (NTS). In order to begin elucidating the mechanisms of nes‐1 actions, we studied the effect of nes‐1 on synaptic activity in NTS neurons using whole‐cell voltage clamp recordings. Bath applied nes‐1 (10nM) did not influence the frequency (freq, 157±49 vs 163±48 events/100s, p=0.85) nor amplitude (amp, 29±4 vs 51±13 pA, p=0.11) of EPSCs recorded from rat medial NTS neurons (n=8) in slice. Nes‐1 did, however, induce an increase in freq (144±45 vs 224±53 events/100s, p=0.03) and amp (57±9 vs 74±12 pA, p=0.02) of IPSCs in 8/9 cells. We next used tetrodotoxin to study spontaneous miniature EPSCs and IPSCs. 10nM nes‐1 did not affect freq (305±68 vs 275±45 events/100s, p=0.37) nor amp (30±2 vs 34±4 pA, p=0.25) of mEPSCs (n=7). Neither the freq (335±102 vs 385±90 events/100s, p=0.41) nor amp (85±12 vs 92±12 pA, p=0.31) of mIPSCs was affected (n=9) by nes‐1. Our findings identify NTS as a site where nes‐1 acts to selectively enhance GABAergic tone and increase inhibitory synaptic events to potentially modify food intake.Research support: NSERC, FQRNT, CIHR.
Roux‐en‐Y Gastric Bypass Surgery Alters the Membrane Properties of Brainstem Neurons
Authors: Browning Kirsteen N , Hajnal Andras 
Published: June 2021

Roux‐en‐Y gastric bypass surgery (GBS) is the most effective treatment for morbid obesity although the effects on brainstem neurons responsible for vagal control of the viscera are unknown. The aim of the present study was to investigate the effects of obesity and GBS on the membrane properties of dorsal motor nucleus of the vagus (DMV) neurons in rats.4‐week old Sprague‐Dawley rats were fed a high fat diet (60% kcal from fat) for 44–59 weeks prior to GBS surgery. Sham rats received the same surgical protocol except intestinal manipulation was performed instead of GBS. Three weeks post‐surgery, whole‐cell patch clamp recordings were made from DMV neurons in thin (300μm) brainstem slices.While the input resistance and action potential (AP) duration of DMV neurons was not different between Sham and GBS rats (298±32MΩ and 5.3±0.4ms (n=20) vs 284±65MΩ and 5.4±0.4ms (n=7), respectively, P>0.05), the amplitude of the after hyperpolarization was higher (16.1±1.0mV vs 11.8±2.4mV, P<0.05). By consequence, the firing frequency of Sham neurons was slower (2.6±0.4 Hz and 5.0±0.5Hz at 90 and 270pA current injection vs 4.7±1.1Hz and 8.7±1.7Hz, respectively, P<0.05).These results suggest that the effects of GBS to reset obesity‐related alterations in ingestive behavior also involve modulation of central neurocircuits responsible for satiety and sensory afferent processing.Supported by NIH DK080899
Roux‐en‐Y Gastric Bypass Surgery Increases The Response Of Central Vagal Neurons To Satiety Neuropeptides
Authors: Browning Kirsteen N , Hajnal Andras 
Published: June 2021

Roux‐en‐Y gastric bypass surgery (GBS) is the most effective treatment for morbid obesity although the effects on brainstem neurons responsible for vagal control of the viscera are unknown. The aim of the present study was to investigate the effects of obesity and GBS on the pharmacological responses of rat dorsal motor nucleus of the vagus (DMV) neurons.4‐week old Sprague‐Dawley rats were fed a high fat diet (60% kcal from fat) for 44–59 weeks prior to GBS surgery. Sham rats received the same surgical protocol except intestinal manipulation was performed instead. Three weeks post‐surgery, whole‐cell patch clamp recordings were made from DMV neurons in brainstem slices (300μm) and the effects of perfusion with either GLP‐1 or CCK8s (both 100nM) on neuronal excitability were measured.In GBS rats, 5 of 5 neurons tested responded to GLP‐1 with an increase in action potential firing rate (219±35%) whereas only 2 of 9 Sham neurons were similarly responsive (P<0.05). In contrast, while 3 of 6 GBS neurons responded to CCK8s with an increase in firing rate (190±21%) this was not significantly different from the response of Sham neurons (2 of 12 responsive neurons, 230±70%, P>0.05).These results suggest that the effects of GBS to reset obesity‐related alterations in ingestive behavior also involves modulation of the responsiveness of central vagal neurons to gastrointestinal satiety neuropeptides.Supported by NIH DK080899