bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin (Ins) induced increase in intracellular calcium ([Ca++]i) in the supraoptic nucleus (SON) neurons requires activation of PI3 kinase (PI3K)
Authors: Song Zhilin , Stevens Wanida , Sladek Celia D
Published: June 2021

Oxytocin (OT) is an anorexic agent. Deficits in OT are associated with human obesity. OT is synthesized by SON neurons of the hypothalamus. These neurons express glucokinases (GK) and Ins receptors (InsR). We showed previously that an increase in glucose induced a rise in [Ca++]i presumably through GK‐driven production of ATP and subsequent closure of ATP dependent potassium channels (KATP). In the present studies, live‐cell calcium imaging was used to evaluate the effect of Ins on [Ca++]i and to determine the underlying molecular signaling mechanisms. Rat hypothalamic explants that include SON were loaded with the calcium sensitive dye, Fura‐2AM. Changes in [Ca++]i were monitored by changes in the ratio of 340/380 emission. Ins (3 ng/ml) induced an increase in [Ca++]i in the majority of SON neurons in the presence of 5 mM glucose and 13 mM KCl (to increase resting membrane potential). The responses were abolished when cells were pretreated with the PI3K inhibitor, wortmannin (10 to 50 nM). Since PI3K mediates Ins‐induced membrane insertion of glucose transporter 4 (GLUT4), these findings suggest that the Ins‐induced increase in [Ca++]i reflects PI3K mobilization of GLUT4, subsequent ATP production from glucose and closure of KATP channels. This is consistent with Ins effects on OT release. Supported by NIH R21‐HD072428.
Hypophysectomy attenuates leptin‐induced tachycardia without affecting leptin's action on appetite and body weight.
Authors: da Silva Alexandre A. , Wang Zhen , Hall John E. , do Carmo Jussara M.
Published: June 2021

Leptin, a hormone produced by adipocytes, regulates energy homeostasis and cardiovascular function by activating its receptors in the central nervous system. Since leptin also modulates pituitary function we examined the role of pituitary hormones in contributing to the effects of leptin on energy homeostasis and cardiovascular function. Male 12‐week‐old hypophysectomized Sprague‐Dawley rats (Hypo, n=5) were instrumented with telemetry probes for determination of mean arterial pressure (MAP) and heart rate (HR) 24‐hrs/day and an intracerebroventricular (ICV) cannula was placed in the brain lateral ventricle for continuous infusion of leptin (15 μg/day). Compared to control rats (Ctrl, n=5), Hypo rats were lighter (215±4 vs 415±6 g), had lower MAP and HR (83±4 and 317±2 vs 105±4 mmHg and 339±4 bpm), with similar caloric intake per gram of body weight (174±19 vs 195±10 kcal/kg) and plasma glucose levels (84±4 vs 80±4 mg/dl). Chronic ICV leptin infusion for 7 days reduced caloric intake (−60%) and body weight (−10%) in both groups. Leptin treatment markedly increased HR in Ctrl rats (~25 bpm) while causing only a modest 8 bpm increase in Hypo rats. Leptin also induced a small increase in MAP in both groups (3 mmHg). These results suggest that hypophysectomy attenuates leptin's effect on HR regulation without altering leptin's ability to suppress appetite and to promote weight loss. (NHLBI‐PO1HL51971/ AHA SDG5680016)
Heterogeneous Vasodilator Pathways Underlying Flow Mediated Dilation are Preserved in Healthy Aging
Authors: Ballard Kevin D. , Tschakovsky Michael E. , Zaleski Amanda L. , Polk Donna M. , Thompson Paul D. , Kiernan Francis J. , Parker Beth A.
Published: June 2021

Blocking nitric oxide (NO) and prostaglandin (PG) formation does not uniformly reduce radial artery (RA) flow mediated dilation (FMD) in young adults. We hypothesized that aging would alter these pathways such that blocking NO and PG would reduce RA FMD in older adults (n = 10 (5 men), 65±3 y). RA FMD was measured after brachial artery infusions of saline, N(G)‐ monomethyl‐L‐arginine (L‐NMMA), and ketorolac (KETO) + L‐NMMA. Data were compared to published data in young adults (n = 16 (8 men), 28±5 y). No sex differences were observed in either age group. L‐NMMA reduced FMD in older adults (8.9±3.6 to 5.9±3.7%) although this was not statistically significant (p = 0.08) and did not differ (p = 0.74) from the reduction observed in young adults (10.0±3.8 to 7.6±4.7%; p = 0.03). Shear stimulus normalization abolished the effect of L‐NMMA in both groups. No main or interaction effects of blocking PG on FMD were observed in young or older adults (p >; 0.11). Heterogeneity was observed in dilatory responses to blockade in older adults. L‐NMMA reduced (n = 6; range = 36–123% decrease) or augmented FMD (n = 4; range = 0.4–122% increase). After PG blockade, reduced (48–103% decrease) and augmented (72–118% increase) FMD responses were observed. Contrary to our hypothesis, NO is not obligatory for RA FMD in older adults. Similar to young adults, redundant vasodilatory phenotypes exist in healthy, older humans. Funded by a HH Open Competition Grant
Age dependency of autonomic response to recumbent positions
Authors: Sato Ryuhei , Sasaki Konosuke , Haga Mayu , Sato Haruka , Kimura Yurie , Kanno Emi , Maruyama Ryoko
Published: June 2021

Little research has been conducted on age‐related differences in autonomic nervous activity and circulation between the various recumbent positions. The purpose of the present study was to evaluate whether young and elderly subjects show differences in the autonomic nervous activity and circulation between the 3 positions (supine, right lateral decubitus, and left lateral decubitus position). We performed electrocardiographic measurements for 58 young (19–34 years) and 50 elderly subjects (63–85 years). The subjects were asked to randomly maintain any of the lateral positions at an angle of over 45° for 10 min after remaining in the supine position. Compared to young subjects, the elderly subjects had significantly lower high frequency (HF) component. However, the 2 groups had no significant difference in the low frequency (LF) component/HF ratio in the supine position. Further, neither of the groups showed any significant change in the HF for any position. In contrast, the LF/HF ratio in the right lateral decubitus position was significantly lesser than that in the supine position only for the elderly group. These findings suggest that age is an important factor affecting the autonomic nervous activity, especially sympathetic nervous activity, in different recumbent positions.
20‐HETE Activates Endothelial ACE via an IKK/NF‐kB Dependent Pathway
Authors: Garcia Victor G , Milhau Laura , Falck John R , Schwartzman Michal L
Published: June 2021

Increased vascular 20‐hydroxyeicosatetraenoic acid (20‐HETE), a cytochrome P450‐arachidonic acid metabolite, promotes vascular dysfunction and hypertension that is dependent, in part, on the renin angiotensin system (RAS). We showed that in cultured human microvascular endothelial cells, 20‐HETE (5 nM) increases angiotensin converting enzyme (ACE) mRNA by 3.1‐fold (± 0.16; p<0.05), ACE protein by 4.2‐fold (±0.99; p<0.05) and cellular and extracellular ACE activity by 2.2‐fold (±0.09; p<0.05) and 1.96‐ fold (±0.16; p<0.05), respectively. These effects were abrogated by co‐treatment with 20‐HEDE, a 20‐HETE antagonist. The increases in ACE mRNA and activity were abolished by EGFR‐tyrosine kinase, MAPK and IKKβ inhibitors. Moreover, transfection of cells with IKKβ siRNA negated 20‐HETE‐induced ACE mRNA and EMSA of nuclear extracts from 20‐HETE‐treated cells showed increased NF‐kB binding activity. Cells transfected with the full‐length human ACE promoter displayed a 2.5‐fold (± 0.24; p<0.05) increase in promoter activation when treated with 20‐HETE (10 nM). 20‐HETE‐stimulated promoter activation was abrogated by 20‐HEDE and was dependent on EGFR, MAPK, IKKβ and NF‐kB activation. This study identifies 20‐HETE as a novel regulator of ACE and suggests that ACE induction is a key mechanism underlying 20‐HETE's ability to promote vascular dysfunction and hypertension.
Circulating inflammatory mediators as potential biomarkers for Heart Failure: a study of the baseline levels in healthy volunteers
Authors: Altara Raffaele , Hessel Marleen H.M. , Manca Marco , La Rocca Hans Peter Brunner , Gorgels Anton P.M. , Hermans Rob J.J. , Janssen Ben J.A. , Boudier Harry A.J. Struijker , Blankesteijn Matthijs W.
Published: June 2021

During Heart Failure (HF) inflammatory mediators are modulated. Our animal experiments showed an increase of four chemokines in the early stage of cardiac hypertrophy development which have never been investigated in this setting. Here we established the baseline values of these molecules in healthy people.

30 volunteers were selected with no known inflammatory condition. A membrane‐based planar method, called Proteome Profiler™, has been improved with fluorescence into a semi quantitative assay. The screening of ~40 inflammatory analytes, including the four identified in animal experiments, was done in serum and plasma of different genders, sampling time and blood components.

The physiological variability of the analytes was homogeneous within the cohort. There were no consistent differences among gender, serum or plasma and time of collection.

In a pilot study of a heterogeneous cohort of CHF patients, two of the four analytes discovered as elevated in animal models for HF had higher concentrations when compared to healthy controls.

The two up‐regulated chemokines in animal models of HF and in HF patients could be candidates for biomarkers for prognostics and diagnostics of HF.
Autophagy in phenoconversion of differentiated and undifferentiated fibroblasts
Authors: Gupta Shivika , Kavosh Morvarid , Chen Shu‐Ru , Ghavami Saeid , Rattan Sunil , Klonisch Thomas , Dixon Ian
Published: June 2021

Cardiac fibroblasts phenoconvert to hypersecretory myofibroblasts and deposit matrix resulting in cardiac fibrosis and autophagy that is associated to fibroproliferative events. Autophagy inhibition was studied in both primary (P0) rat cardiac fibroblasts (PF) and mouse embryonic fibroblasts (MEF). Autophagy was inhibited in PF using Baf‐A1 or 3‐MA while MEF ATG3 and ATG5 KO were also used. Western blot analysis, Immunofluorescence, and transmission electron microscopy were used to investigate autophagy and fibroblast to myofibroblast phenoconversion. α‐SMA and ED‐A fibronectin were assessed as phenoconversion markers. Inhibition of autophagy was revealed by punctate LC3‐II staining and double membrane autophagosomes in combination with decreased myofibroblast markers in PF vs. controls. Inhibition of autolysosome formation and accumulation of autophagosomes were found in Baf‐A1 treated cells. Conversely, ATG3 and ATG5 KO MEF cells showed increased myofibroblast markers vs. WT controls. Increased α‐SMA was seen in MEF ATG3 and ATG5 KO vs. controls while inhibition of autophagy in PFs showed diminished myofibroblastic phenotype vs. controls. A link between fibroblast phenoconversion and autophagy is established. This effect is dependent on cell type eg, PFs vs. MEFs. This finding illustrates that autophagy functions in a variable manner in differentiated vs. non‐differentiated fibroblasts.
LPS induces pp60c‐srcmediated tyrosine phosphorylation of hsp90 in lung vascular endothelial cells and mouse lung
Authors: Barabutis Nektarios , Handa Vaishali , Dimitropoulou Christiana , Rafikov Ruslan , Snead Connie , Kumar Sanjiv , Joshi Atul , Thangjam Gagan , Fulton David , Black Stephen M , Patel Vijay , Catravas John D
Published: June 2021

Post‐translational modifications of Hsp90 may affect client protein binding. We investigated tyrosine (Y) phosphorylation of Hsp90 in inflammation. LPS, a prototypical inflammatory agent, induced concentration‐dependent Y phosphorylation of Hsp90a and Hsp90β in human lung microvascular endothelial cells (HLMVEC). Mass spectroscopy identified a major site of Y phosphorylation as Y309 of Hsp90β (Y300 of Hsp90a). LPS‐induced pY‐Hsp90 was prevented by the Hsp90 inhibitor 17‐AAG in vitro as well as in lungs from LPS‐treated mice, in vivo. Furthermore, 17‐AAG also prevented LPS‐induced pp60src activation. LPS‐induced pY‐Hsp90 was also prevented by the pp60src inhibitor, PP2. Additionally, Hsp90 phosphorylation was induced by infecting cells with a constitutively active pp60src adenovirus, whereas either a dominant‐negative pp60src adenovirus or reduced expression of pp60src by a specific siRNA, prevented the LPS‐induced Y phosphorylation of Hsp90. Transfection of HLMVEC with the non‐phosphorylatable Hsp90 Y300F mutant, prevented the LPS‐induced Hsp90 Y phosphorylation and showed a reduced ability to bind the Hsp90 client proteins eNOS and pp60src. We conclude that inflammatory stimuli cause post‐translational modifications of Hsp90 that are Hsp90‐inhibitor‐sensitive and may be important to the pro‐inflammatory actions of Hsp90. (Supported by HL 06693, HL 093460 and HL 101902).
The Effects of Combined Exercise on Body Compositions and Blood Lipid Profiles in Korean Obese Women
Authors: Jin Haeng Mi , Kim Pyeong Jung
Published: June 2021

The purpose of this study was to investigate the effects of a combined exercise including weight training, ashtanga yoga, jazzercise on the body compositions and blood lipid profiles in Korean obese women. Twenty obese women (more than 30% of body fat (BF)) were allocated combined exercise (CE, n=10) and single exercise (SE; jazzercise only, n=10) groups. They took exercise for 90 minutes a day, 3 times a week during 12 weeks. The body compositions and blood lipid profiles measured before and after exercise. Collected data were analyzed with SPSS program (version 12.0) by using paired and independent t‐tests and Pearson's correlation. After 12 weeks exercise, CE presented decreased weight, BMI, % BF, and increased muscle mass (MM). SE also presented decreased weight, BMI, and % BF but there was no change in MM. Compared to SE, CE had higher MM change after exercise (P<0.01). CE and SE presented decreased TC and TG; however only CE had HDL increase after exercise. Compared to SE, CE presented higher TG reduction (P<0.01) and HDL increase (P<0.001) after exercise. In both groups, there was negative correlation between changes of MM and TG (P<0.01); whereas, fat mass and % BF changes were positively correlated with TG change (P<0.05). In conclusion, CE can improve body compositions and blood lipid profiles than SE in Korean obese women. In addition, body composition changes after exercise may ameliorate blood lipid profiles.
Exercise during pregnancy attenuates prenatal high‐fat diet‐induced hypermethylation of the Pgc‐1α gene and protects against age‐induced glucose intolerance in the offspring
Authors: Laker Rhianna Che , Lillard Travis , Okutsu Mitsuhara , Connelly Jessica , Yan Zhen
Published: June 2021

Maternal obesity predisposes the fetus to metabolic disease later in life. We determined whether maternal diet and exercise impose epigenetic influences in offspring on a metabolic master regulator, peroxisome proliferator activated receptor γ co‐activator 1α (Pgc‐1α). Female C57BL6 mice were exposed to either normal chow, high‐fat diet (HFD), or voluntary wheel running exercise with HFD for 6 wks prior to and throughout pregnancy. Genomic DNA from skeletal muscle was isolated from neonatal offspring for DNA methylation analysis of the Pgc‐1α promoter using pyro‐sequencing. Litter size and offspring weight were not different between groups. Pgc‐1α methylation of CpG ‐260, a site shown to be associated with metabolic disease in humans, was increased (P<0.05) in offspring skeletal muscle when exposed to maternal HFD. The adult offspring of high‐fat fed mothers displayed impaired glucose tolerance and insulin sensitivity in later life. Maternal exercise attenuated the maternal HFD‐induced hypermethylation at birth and protected adult offspring from age‐related decline in metabolic function. Funded by the Partners’ Fund from the Robert M. Berne Cardiovascular Research Center and Thelma R. Swortzel Award, University of Virginia.
Contributions of nitric oxide and prostaglandins to exercise hyperemia in young obese adults
Authors: Johansson Rebecca Elin , Harrell John W , Limberg Jacqueline K , Crain Meghan K , Rousseau Cameron L , Yanke Peter A , Sebranek Joshua J , Walker Benjamin J , Eldridge Marlowe W , Schrage William G
Published: June 2021

Nitric oxide (NO) and prostaglandins (PGs) play important roles in exercise hyperemia in healthy humans, but the role of NO & PGs in young obese (OB) adults is currently unknown. We hypothesized the relative contribution of NO and PGs to exercise hyperemia would be lower in young OB adults when compared to lean adults. 11 healthy lean (27±2yrs, BMI=23±1) and 7 OB adults (23±2yrs, BMI=38±4) performed two 10‐minute trials of dynamic forearm exercise (20 contractions/minute) at 15% of maximal voluntary contraction. A brachial artery catheter was used for local infusion of the NO synthase inhibitor, L‐NMMA, alone or in combination with the cycloxygenase inhibitor, ketorolac. L‐NMMA or ketoroloac was infused during the last 5 minutes of each exercise trial to achieve single and double blockade respectively. Forearm blood flow (FBF) was measured using Doppler ultrasound, and forearm vascular conductance (FVC) was calculated (FBF÷BP=FVC). From steady state exercise, the relative change in FVC with L‐NMMA was similar between groups (Lean−34±10 vs. OB−35±15%). With the addition of ketorolac, the relative change in FVC was opposite between groups (Lean−7±8 vs. OB+30±17%, p=0.02). We conclude the contribution of NO to exercise hyperemia appears intact in young OB adults, although they may produce more vasoconstrictor PGs that alter blood flow regulation. Support: NIH R01 HL105820.
Contribution of nitric oxide in the contraction‐induced rapid vasodilation in young and older adults
Authors: Casey Darren P. , Walker Branton G. , Ranadive Sushant M. , Taylor Jennifer L. , Joyner Michael J.
Published: June 2021

We tested the hypothesis that reduced nitric oxide (NO) bioavailability contributes to the attenuated peak and total vasodilation following single muscle contractions in older adults. Young (n=8; 25 ± 2 yr) and older (n=9; 67 ± 2 yr) adults performed single forearm contractions at 10, 20 and 40% of maximum during saline infusion (control) and NO synthase (NOS) inhibition via L‐NMMA. Brachial artery diameter and velocities were measured using Doppler ultrasound and forearm vascular conductance (FVC) was calculated from blood flow (ml/min) and blood pressure (mmHg). Peak and total vasodilator responses (ΔFVC from baseline) were attenuated in older adults at all intensities (P < 0.05). NOS inhibition reduced the peak ΔFVC at 10% (95 ± 13 vs. 59 ± 10), 20% (134 ± 11 vs. 90 ± 12) and 40% (222 ± 30 vs. 143 ± 24) in young subjects (P < 0.05 for all) and in older adults at 10% (61 ± 5 vs. 48 ± 7, P < 0.05) and 20% (90 ± 8 vs. 70 ± 8, P < 0.05), but not 40% (129 ± 13 vs. 105 ± 11, P = 0.12). The relative (%) reduction in peak ΔFVC due to NOS inhibition was greater in young vs. older adults at 20% (−36 ± 5 vs. −22 ± 5%, P < 0.05) and 40% (−35 ± 7 vs. −17 ± 7%, P < 0.05). The reduction in the total vasodilator response (area under the curve) with NOS inhibition was also greater in young vs. older adults at 20 and 40%. Our data suggest that contraction‐induced rapid vasodilation is mediated in part by NO; however, it appears the NO contribution in the response is greater in young adults.
miR204/RUNX2 axis regulates HIF‐1α activation in pulmonary arterial hypertension
Authors: Margaillan Guillaume , Barrier Marjorie , Potus François , Meloche Jolyane , Courboulin Audrey , Couture Christian , Bonnet Pierre , Provencher Steeve , Bonnet Sebastien
Published: June 2021

Pulmonary arterial hypertension (PAH) is characterized by proliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMC). This phenotype is sustained by an elusive HIF‐1α activation RUNX2 activates HIF‐1α in vascular diseases, and is controlled by miR‐204 that is decrease in PAH. We hypothesized that miR‐204 downregulation triggers RUNX2‐dependent activation of HIF‐1 contributing to PAH.

HIF‐1α and RUNX2 activation are increased in humans and rats distal PA and PAH‐PASMC vs control. In PAH‐PASMC, RUNX2 downregulation resulted in HIF‐1α inhibition (immunoblot, IF; p<0.05) decreasing proliferation (p<0.05) and resistance to apoptosis (p<0.05); while RUNX2 upregulation in control PASMC has the opposite effects. As RUNX2 is one of the predicted targets of miR‐204 its upregulation in PAH‐PASMC could be explained by the miR‐204 downregulation seen in PAH. Thus miR‐204 supplementation (mimic) in PAH‐PASMC decreases RUNX2 and HIF‐1α activation (Western blot; p<0.05), while miR‐204 downregultion in control PASMC increases RUNX2 and HIF‐1. In vivo, siRUNX2 nebulization or miR‐204 nebulization in SUGEN‐induced PAH rats reverses PAH.

We demonstrated the implication of miR‐204/RUNX2 axis in HIF‐1 activation in PAH.
Genotyped adipocytes to monitor adiponectin expression in response to environmental stressors
Authors: Zhang Chen , Alley Joshua B. , Samy Sanjay A. , Bohman Danna , Bovenzi Frank , Fitzgerald Laura , Prot Jean‐Matthieu , Shuler Michael L. , Ariza‐Nieto Magnolia
Published: June 2021

In 2008, the world health organization reported more than 1.4 billion adults are overweight in the world. Obesity is associated with diabetes, heart disease and certain cancers. Adiponectin is an adipocyte synthesized and secreted by adipose tissue. Several studies indicated that obese patients are presented with hypoadiponectinemia. A set of single nucleotide polymorphism SNP's associated with hypoadiponectinemia are of used to characterize the cells in this study. The goal is to develop normal human genotyped cell lines and load them in the well defined “body‐on‐a‐chip” BOAC systems. The BOAC is a microfabricated device based on a physiologically based‐pharmacokinetic (PBPK) model. The aim is to identify ways to modulate the expression of adiponectin using drugs, dietary supplements or functional components in the food matrix. Bone marrow or omental fat are collected from patients corresponding to IRB approved clinical trial GHS # 1207–27. Each patients is genotyped for a series of SNP's including ARL15 (rs4311394‐G), ADIPOQ (rs6444175‐G), ADIPOQ (rs266717‐T), ADIPOQ (rs1426810‐G), ADIPOQ (rs1648707‐C). Mesenchymal stem cells are isolated, expanded and differentiated into organ like cell lines. Preadipocytes are loaded onto the BOAC device and adiponectin released on media is monitored in response to environmental stressors applied to the system. Funding Cornell University Center on the Microenvironment and Metastasis (CMM) outreach pilot grant and Guthrie Foundation Investigator‐Initiated Research Grant.
Temperature dependent variation in respiratory patterns and spiracular control in Rhodnius prolixus
Authors: Heinrich Erica , Bradley Timothy
Published: June 2021

Our understanding of insect respiratory control indicates that spiracular activity is regulated by two interacting feedback loops which respond to changes in internal pCO2 and pO2. Since spiracles open in response to a specific pCO2 threshold, the volume of CO2 released in a burst by a discontinuously respiring insect should remain constant. However, previous studies which manipulated metabolic rate via temperature found that burst volume decreases at high temperatures. We used Rhodnius prolixus to test if this variation is caused by changes in metabolic rate or by an effect of temperature on spiracular control. We increased metabolic rate by either increasing ambient temperature or feeding a bloodmeal. Burst volume decreased significantly as temperature increased from 18°C to 38°C (ANOVA, F=89.58, p<0.001) but showed no relationship to metabolic rate in fed animals measured at 24°C (BV= −0.0016MR + 0.0243, R2=0.0015). At high temperatures, insects abandoned discontinuous respiration at lower metabolic rates than fed insects. It is clear that insect respiratory patterns are influenced by both temperature and metabolic rate. Support provided by NSF IOS‐0920683 (TJB).
TRPV1 in the paraventricular nucleus of the hypothalamus is involved in the regulation of systemic blood glucose levels
Authors: Zsombok Andrea , Miyata Kayoko , O'Hare James D , Fourrier Torrey L , Krantz Amanda M , Derbenev Andrei V
Published: June 2021

The autonomic nervous system plays a pivotal role in the regulation of glucose homeostasis. Transient receptor potential vanilloid type 1 (TRPV1) receptors are expressed in the paraventricular nucleus (PVN) of hypothalamus and liver‐related PVN neurons are controlled by TRPV1‐dependent excitatory neurotransmitter release. However, the effect of TRPV1 activation on whole body glucose homeostasis remains to be determined. Capsaicin (0.5 nmol), a TRPV1 agonist was injected bilaterally into the PVN and systemic blood glucose levels, serum insulin levels, expression of proteins involved in hepatic gluconeogenesis and in glucose uptake in the skeletal muscle were measured in male CD1 mice. Activation of TRPV1 in the PVN significantly decreased systemic blood glucose levels. The reduction was detectable up to 30 min, with a maximum approximately at 15 min. The glucose lowering effect of TRPV1 was suppressed in the presence of the glutamate receptor antagonist, kynurenic acid. Serum insulin levels did not show significant difference between groups. Activation of TRPV1 in the PVN decreased hepatic PEPCK and pyruvate carboxylase expression levels and increased phosphorylation of glycogen synthase kinase 3 in the skeletal muscle. Our data suggest that TRPV1 in the PVN modulates systemic blood glucose levels. Supported by Tulane BIRCWH 2K12HD043451, Tulane Aging CoBRE P20GM103629.
Influence of Fish Oil on Skeletal Muscle Mitochondrial Energetics and Lipid Metabolites during High‐Fat Diet
Authors: Lanza Ian R. , Blachnio‐Zabielska Agnieszka , Zabielski Piotrek , Nair K. Sreekumaran , Jensen Michael , Lebrasseur Nathan
Published: June 2021

Omega‐3 polyunsaturated fatty acids (n‐3 PUFAs) protect insulin sensitivity and glucose homeostasis in rodent models of insulin resistance. These effects of n‐3 PUFAs are linked with anti‐inflammatory properties, but emerging data suggests that mechanisms may also converge on mitochondria. We evaluated the influence of dietary n‐3 PUFAs on mitochondrial physiology in the context of high‐fat diet (HFD) in mice. We hypothesized that the insulin‐sensitizing effects of n‐3 PUFAs would be accompanied by enhanced mitochondrial function in skeletal muscle, leading to attenuated levels of lipid metabolites known to interfere with insulin signaling. We fed mice HFD with or without fish oil for 10 weeks. HFD decreased glucose tolerance, but not in the presence of fish oil. Skeletal muscle long chain acyl coenzyme‐As and ceramides were significantly elevated with HFD, but attenuated in the presence of fish oil. Mitochondrial oxidative capacity was similarly increased in mice fed HFD with and without fish oil. These results indicate that n‐3 PUFAs protect insulin sensitivity, in part, by preventing the accumulation of lipid intermediated that interfere with insulin action. Furthermore, the respiratory function of skeletal muscle mitochondria does not appear to be a major factor in ectopic lipid accumulation, diet‐induced insulin resistance, or the protective effects of n‐3 PUFAs on insulin sensitivity.
Activation of gut calcium‐sensing receptor by peptide agonists promotes glucose tolerance in rats
Authors: Hira Tohru , Muramatsu Maya , Mitsunaga Arimi , Sato Eri , Nakajima Shingo , Kitahara Yoshiro , Eto Yuzuru , Hara Hiroshi
Published: June 2021

Purpose

Calcium‐sensing receptor (CaSR) is widely expressed in various tissues including gastrointestinal tract. However, the role of gut CaSR in digestion/absorption of macronutrients is yet not known. In the present study, we examined whether single oral administration of CaSR agonist peptides affects glycemic response in rats, and also investigated the mechanism by which CaSR agonists modulate the glycemic response.

Methods

Glucose tolerance tests were performed under oral or duodenal administration of various CaSR agonist peptides {γGlu‐Cys (γEC), protamine, and poly‐lysine} in conscious rats. Gastric emptying rate was measure by using phenol red method.

Results

Oral and duodenal administration of CaSR agonists (γEC, protamine, and poly‐lysine) attenuated the glycemic response under oral glucose tolerance test. Gastric emptying rate was decreased by oral administration of these CaSR agonists. Glucose‐lowering effect of the agonists was partially cancelled by luminal pretreatment with a CaSR inhibitor. In addition, intraperitoneal treatment with 5‐HT3 receptor antagonist partially reversed the glucose‐lowering effect of the agonists.

These results demonstrate the activation of gut CaSR by peptide agonists attenuates glycemic response. Involvement of 5‐HT3 receptor and delayed gastric emptying are suggested in the glucose‐lowering effect of these CaSR agonists.
CCk8 Enhances Anti‐diabetic Efficacy of GLP1
Authors: Chen Yanyun , Song Min , Liu Fa , Lockwood John , Alsina Jordi , Hammond Craig
Published: June 2021

The objective of the study is to investigate potential synergistic or additive effects of combining GLP1 with CCK8 in diet induced obese (DIO) mice. Glucagon‐like peptide‐1 (GLP1) is a peptide hormone secreted by the intestinal L cells in response to food ingestion. It augments glucose‐mediated insulin secretion, inhibits glucagon secretion, reduces appetite and food intake, and delays gastric emptying. Another gastrointestinal peptide released upon food ingestion is cholecystokinin (CCK). CCK is secreted from the duodenal I cells in response to fat and protein. CCK can stimulate pancreatic enzyme secretion, increase gall bladder contractions and delay gastric emptying. CCK also triggers a gut‐brain‐liver neuronal network to control glucose production. The major form of biologically active CCK is CCK‐8. When DIO mice were infused with low doses of a GLP1 analog or a CCK8 analog for two weeks, no effects on food intake or body weight were observed. However, the group received both peptides (GLP1+CCK8) showed significant reductions in food intake and body weight. At the completion of two‐week treatments, both GLP1‐ and CCK8‐treated groups decreased glucose excursion in response to an oral glucose challenge. The GLP1+CCK8 group demonstrated additive effects on glucose lowering. In conclusion, combination of GLP1 with CCK8 has the potential to be a more efficacious therapy for type II diabetes.
Role Of Metabolism In Fructose‐Induced GLUT5 Regulation
Authors: Patel chirag r , Douard Veronique r , Ferraris Ronaldo
Published: June 2021

Marked increases in fructose consumption have been linked to increases in prevalence of metabolic diseases. Fructose upregulates its own absorption by increasing the expression and activity of the intestinal fructose transporter GLUT5. Defects or limits in regulation leads to adult‐onset fructose intolerance or to fructose malabsorption in infants. Fructose upregulates GLUT5 within hours after it is fed, gavaged or perfused into the intestinal lumen, but it is not clear whether GLUT5 induction by luminal fructose requires metabolism of this sugar. Ketohexokinase (KHK) catalyzes the first step of fructose metabolism to fructose‐1‐phosphate. Adult wild type and KHK−/− mice were divided into three groups each receiving 30% glucose, fructose or lysine by gavage. In wildtypes, intestinal GLUT5 activity and expression increased in fructose‐gavaged mice compared to those gavaged with glucose or lysine. Strikingly, fructose failed to induce GLUT5 in KHK−/− mice. These effects are specific, as the glucose transporter SGLT1 activity and expression did not vary with diet. Thus, metabolism plays an essential role in mediating fructose‐induced GLUT5 regulation. (NSF IOS‐1121049).
Effect of EGCG on the expression and activity of P‐glycoprotein in breast cancer cells.
Authors: Morales Ana Isabel Gonzaga , Fragoso Lourdes Rodriguez , Esparza Jorge Reyes
Published: June 2021

Globally breast cancer is the most common cancer in women. The chemotherapy treatment is successful in many instances, however, some patients do not respond satisfactorily. The multi‐drug resistance is considered the principal cause of failure of chemotherapy. There are different mechanisms by which originates multidrug resistance. It has been found that resistance is associated with ABC transporters, mainly P‐glycoprotein (P‐gp). Displayed can be modulated by compounds of natural origin, such as green tea and its polyphenols, including (−)‐Epigallocatechin‐3‐gallate (EGCG). The aim of this study is to observe the effect of EGCG on expression and activity of P‐glycoprotein in cell lines of breast cancer. We use the cell line MCF‐7. We evaluated the effect of EGCG on viability by MTT assay and fluorescence. Also we evaluated the effect on the expression of P‐gp by western blot and immunofluorescence. The activity was measured by the technique of Rhodamine123 accumulation. We found that EGCG does not cause cell death at concentrations below 100 μM. However, concentrations greater than 100 μM produces two types of cell death concentration dependent, EGCG 250 μM produces death by apoptosis and concentrations greater than 500 μM produces death by necrosis. EGCG decreases the expression and activity of Pg‐p in a dose dependent. We conclude that EGCG can reverse drug resistance associated with P‐gp in vitro assays.
Use of membrane permeable ligands as pharmacological chaperones to rescue the plasma membrane expression of a mutant muscarinic M1 receptor
Authors: Sawyer Gregory William , Shults Crystal
Published: June 2021

In this investigation, we determined whether membrane permeable muscarinic receptor selective agonists, antagonists, and allosteric ligands cause a mutant M1 muscarinic receptor to traffic from ER to the plasma membrane of CHO cells. This receptor, M1LL/AA, possesses a L430A/L431A double point mutation and these mutations caused the receptor to be retained in the ER. We characterized the effect of membrane permeable ligands on the cellular distribution of GFP‐tagged M1LL/AA receptors transiently expressed in CHO cells using confocal microscopy and the ER marker DsRed‐ER. Ligands that caused GFP‐tagged M1LL/AA receptors to redistribute from the ER were then used in intact, whole cell [3H]N‐methyscopolamine ([3H]NMS) binding assays. In these assays, CHO cells transiently expressing M1LL/AA receptors were incubated with equally spaced concentrations (0.5 log unit) of ligand and then washed and incubated with [3H]NMS. Using this approach, we found that membrane permeable agonists (oxotremorine and pilocarpine), antagonists (atropine and scopolamine) and allosteric ligands (TBPB, VU0364572, and VU0357017) cause M1LL/AA receptors to traffic from the ER to the plasma membrane of CHO cells. Overall, we have developed a model system to learn more about using ligands as pharmacological chaperones to rescue the expression of mutant GCPRs. This work was supported by NINDS [Grant 1R15‐NS57742].
Selective Estrogen Receptor Modulators Tamoxifen, Pterostilbene, Raloxifene and Clomiphene fail to stimulate the Hepatic Expression of Estrogen Responsive Genes Encoding the Avian Apolipoprotein II and Vitellogenin
Authors: Bhatt Vrushank Dharmesh , Ratna Warren N
Published: June 2021

Apolipoprotein (apo) II and vitellogenin (VTG) I, II & III are yolk proteins expressed in the avian liver in response to estrogen during egg‐laying. Estrogenic stimulation of the hepatic expression of apo II and VTG is due to both transcriptional increase and mRNA stabilization. We had previously shown the expression of the estrogen‐responsive mRNA stabilizing factor, which stabilizes apo II mRNA to be stimulated by estrogen, and selective estrogen receptor modulators (SERMs) such as genistein, resveratrol, tamoxifen, Aroclor, chlordecone (Kepone) and hexachlorophene, but inhibited by clomiphene, toxaphene and bisphenol‐A. Reverse Transcription‐Polymerase Chain Reaction (RT‐PCR), Northern blot analysis, RNase protection assays on whole cell RNA and Western blot analysis of cytosolic extracts from livers of roosters treated with estrogen or SERMs such as tamoxifen, pterostilbene, raloxifene and clomiphene showed stimulation of transcription and expression of apo II and VTG I, II & III by estrogen but not the SERMs, demonstrating selective regulation of estrogen‐responsive genes by the latter. This work was supported by science research funds from Arnold and Marie Schwartz College of Pharmacy, Long Island University, NY.
Effects of Radiation Exposure and Dietary Iron on Liver Metabolic Gene Expression
Authors: Wotring Virginia E
Published: June 2021

Increased exposure to gamma radiation and subsequent oxidative effects are among the physiological stressors associated with spaceflight. High iron is another potential oxidative stressor, and increased iron stores have been noted in astronauts. These stressors (high iron and gamma radiation) alone, and together, were studied in rats to determine the effects on liver gene expression in 4 groups of 8 animals: adequate iron/no radiation, adequate iron/+ radiation, moderately high iron/no radiation, and moderately high iron/+ radiation. Animals were exposed to either 3 Gy gamma radiation (fractionated as eight 0.375 Gy exposures with 48 hrs between exposures), or sham exposures. Gene expression was measured with RT‐qPCR for enzymes involved in drug metabolism, reduction‐oxidation homeostasis, and DNA repair. Expression of Abcb1b, which encodes an ATP‐dependent drug efflux pump for xenobiotics, decreased about 2‐fold in the animals on a moderately high iron diet compared to those on an adequate iron diet. However, in the both of the radiation groups, regardless of diet, Abcb1b expression was elevated compared to the controls given the sham exposure, by 13‐fold (adequate iron diet) and by 11‐fold (high iron diet). This result indicates that these two oxidative stressors examined in this study are not equivalent.
Preventable decrements of cerebral microvascular volume and vasodilatation in a rat model of diet‐induced Vascular Cognitive Impairment: non‐invasive detection by absolute Near Infrared Spectroscopy
Authors: Vayman Vered , Martsiano Shani , Weinstein Merav , Nachum‐Biala Yaarit , Troen Aron M
Published: June 2021

The brain microvascular circulation has considerable structural plasticity and can expand or regress in response to metabolic and dietary challenges We hypothesized that such changes might underlie the association of folate deficiency and hyperhomocysteinemia with cerebrovascular and neurodegenerative disease. Previously, we found that dietary folate deficiency can impair cognition in Sprague Dawley rats and that this can be mitigated by adding methionine to the folate‐deficient diet. Separately, we used non‐invasive absolute Near Infrared Spectroscopy (NIRS) to obtain evidence of brain microvascular changes in folate‐deficient rats, finding diminished cerebral blood volume and vasoreactivity compared to controls. Here we extend these findings by showing that folate deficiency reproducibly diminishes cerebral blood volume and vascular reactivity, and that these changes can be reversed by methionine supplementation. Our findings are consistent with the hypothesis that reversible microvascular changes may contribute to cognitive impairment. The ability to non‐invasively manipulate, detect and measure such changes can help to understand the role of microvascular plasticity in dementia.

Support: Israel Science Foundation and EU‐IRG
Improving the redox potential of gestational diabetic endothelial cells: protective actions of sulforaphane
Authors: Patel Bijal , Siow Richard CM , Mann Giovanni E.
Published: June 2021

Rationale

Gestational diabetes mellitus (GDM) is characterized by hyperglycemia and/or impaired glucose tolerance and affects 2–7% of pregnancies. In utero exposure to enhanced oxidative stress increases the risk of type 2 diabetes and cardiovascular disease in offspring due to fetal programming. We have previously shown that GDM impairs nuclear factor erythroid 2‐related factor 2 (Nrf2) mediated upregulation of heme oxygenase‐1 (HO‐1) and NAD(P)H: quinone oxidoreductase 1 (NQO1) expression in fetal umbilical vein endothelial cells (HUVEC).

Methods and Results

In the present study, we examined whether SFN, a known electrophilic inducer of Nrf2, modulates antioxidant stress protein expression differentially in HUVEC from normal and GDM pregnancies. Cells were treated with SFN (2.5μM) for 0–24h, immunoblotted for HO‐1, NQO1 and Nrf2 and mRNA levels determined by qRT‐PCR. NQO1 activity was determined using the Prochaska assay. Immunfluorescence was employed to study nuclear translocation of Nrf2. Basal levels of HO‐1 and NQO1 mRNA and protein expression were significantly lower in GDM (p<0.05), however SFN significantly (p<0.05) upregulated mRNA (HO‐1 by ~5‐fold, NQO1 by ~2‐fold) and protein (12h and 24h) levels and increased NQO1 activity.

Conclusions

Our findings suggest that impaired antioxidant defences in cells derived from GDM pregnancies, may be restored by SFN. We hypothesize that SFN may potentially maintain antioxidant defences and thereby delay the onset and consequences of GDM.

Supported by British Heart Foundation
Postprandial Blood Glucose Response to Meals of Varying Composition; Influence of BMI and Physical Fitness
Authors: Hopper Mari K. , Koch Carynn E , Koch Jennifer L
Published: June 2021

We investigated the effects of meal composition and levels of physical fitness and body composition on postprandial blood glucose. For 20 college students BMI was determined and classified (High BMI >;30; Low BMI ≤29). Participants self assessed their physical fitness using a Likert type scale (High Fit >;5; Low Fit ≤5). Subjects completed an oral glucose tolerance test (OGTT) and in following weeks consumed one of three breakfast meals (all 540 kcals) following an overnight fast in random order: 1) energy drink and toaster pastry; 2) ham and cheese; and 3) bagel, peanut butter, and banana. An Accucheck® glucometer was used to determine fasted, 30, 60, and 120 minute postprandial blood glucose levels. All fasted glucose values were normal. Two‐hour OGTT glucose remained above 130 mg/dL in both the High BMI and Low Fit groups. Low Fit glucose levels were significantly higher than High Fit at all time periods for both toaster pastry and bagel meal treatments. Similarly, High BMI glucose levels were higher than Low BMI by 10.5% at 30 min, 15.8% at 60 min, and 20.8% at 120 min. The greatest differences in blood glucose level occurred at two hours following the energy drink and toaster pastry (Low BMI 90±3.3 vs High BMI 120±15.3 mg/dL). These results indicate that postprandial blood glucose response depends on both meal composition and the individual's BMI and level of physical fitness.
Exploring mechanisms that attenuate myocardial glucose uptake in response to acute hyperglycemia: identification of a vicious metabolic cycle
Authors: Joseph Danzil , Kimar Charlene Patricia , Essop M. Faadiel
Published: June 2021

Acute hyperglycemia (AHG) e.g. high post‐prandial glycemic excursions are linked to lower glucose uptake. Chronic hyperglycemia can trigger reactive oxygen species (ROS) production and increase non‐oxidative glucose pathway (NOGP) flux, i.e. polyol pathway (PP), hexosamine biosynthetic pathway (HBP), advanced glycation end‐products (AGE), PKC, and contribute to insulin resistance. Since it is unclear whether a similar scenario exists with AHG, we hypothesized that ROS plays a pivotal role in AHG‐mediated NOGP activation and decreased myocardial glucose uptake. H9c2 cardiomyoblasts were exposed to 25 mM glucose for 24 h vs. 5 mM glucose controls ± therapeutic agents during last h of glucose exposure: a) antioxidant (250 μM 4‐OHCA), b) NOGP inhibitors − 100 μM aminoguanidine (AGE); 5 μM chelerythrine (PKC); 40 μM DON (HBP); and 10 μM zopolrestat (PP). ROS levels (mitochondrial, intracellular) and glucose uptake were evaluated by flow cytometry. AHG significantly increased mitochondrial and intracellular ROS levels, activated NOGP and blunted glucose uptake. However, transketolase (TK) activity (marker of pentose phosphate pathway) was not significantly altered. By contrast, 4‐OHCA treatment significantly reduced ROS, TK activity, NOGP activation and normalized glucose uptake. Each individual NOGP inhibitor blunted activation of the other pathways examined here. Our study reveals a convergence of downstream NOGP effects and identifies a vicious metabolic cycle, i.e. AHG stimulates NOGP that further fuel its own activation by generating more oxidative stress and further diminishing glucose uptake. Antioxidant treatment may be a useful approach to counter the potential detrimental effects of pronounced, acute hyperglycemic episodes.
Pre‐diagnostic Leukocyte Genomic DNA Methylation and the Risk of Colorectal Cancer in Women
Authors: Cho Eunyoung , Nan Hongmei , Giovannucci Edward L. , Wu Kana , Selhub Jacob , Paul Ligi , Rosner Bernard , Fuchs Charles
Published: June 2021

Objective

We evaluated the association between pre‐diagnostic leukocyte genomic DNA methylation levels and colorectal cancer risk.

Methods

We conducted a nested case‐control study of 358 colorectal cancer cases and 661 matched controls within the Nurses’ Health Study of women. Among the controls, we further examined major plasma components in one‐carbon metabolism pathway in relation to genomic DNA methylation levels. Liquid chromatography electrospray ionization mass spectrometry method was used to measure DNA methylation. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression.

Results

Genomic DNA methylation levels were not associated with colorectal cancer risk. Compared with women in the lowest quintile of methylation, the multivariate OR of colorectal cancer was 1.32 (95% CI, 0.82–2.13) for those in the highest quintile (p for trend, 0.45). We did not find associations of major plasma components of one‐carbon metabolism or several risk factors for colorectal cancer with genomic DNA methylation levels. The plasma components and risk factors for colorectal cancer did not modify the association between genomic DNA methylation and colorectal cancer risk.

Conclusions

We found no evidence that hypomethylation of leukocyte genomic DNA increases risk of colorectal cancer among women. Additional studies are needed in other populations including men.

Funding source: This work was supported by research grants CA136950 and CA55075 from the National Institutes of Health
Cutaneous vasomotor control during mild‐cold exposure in young women complaining of unusual coldness
Authors: Yamazaki Fumio , Sone Ryoko
Published: June 2021

In Japan, we often encounter women complaining of physical coldness, especially in the acral portion of the extremities, even under normal temperature conditions. In this study, we examined the cutaneous vasomotor reflex response and thermal sensation during mild‐cold stress in ten young women complaining of unusual coldness (C group) and nine young women not suffering from coldness (N group). The room temperature was decreased from 29.5°C at the 20‐minute baseline to 23.5°C. Skin blood flow (SkBF) was monitored from the calf, dorsal foot, and toe by laser‐Doppler flowmetry. Cutaneous vascular conductance (CVC) was calculated as the ratio of SkBF to blood pressure and expressed relative to the baseline value at 29.5°C. The mean skin temperature (Tsk) similarly (P>;0.05) decreased during mild‐cold exposure in C and N groups. In the calf and dorsal foot, local Tsk and CVC similarly (P>;0.05) decreased during cold exposure in both groups, while Tsk in the toe was lower in the C group in the later phase of cold exposure. The rating scores of cold discomfort for both the body and lower extremities were greater (P<0.05) in the C group than in the N group throughout the cold exposure. In the C group, the augmented sensitivity of thermal sensation to cold did not accompany the altered cutaneous vasoconstrictor sensitivity of the legs, but was partly due to a lower temperature of the acral portion of the lower extremities.