bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of endoplasmic reticulum stress attenuates aorta coarctation induced hypertension and kidney injury in diabetic Goto Kakizaki rats (LB724)
Authors: Wang Zhen , do Carmo Jussara , da Silva Alexandre , Hall John 
Published: June 2021

Hypertension (HT) is common in diabetes and substantially increases the risk for diabetic nephropathy. To investigate the mechanisms by which HT and diabetes interact to promote nephropathy, 6 month‐old male Goto‐Kakizaki (GK) rats, a model of spontaneous type 2 diabetes, were used in this study. HT was induced by aorta coarctation (AC) between the renal arteries to produce HT plus diabetes in the right kidney (above AC) and normal blood pressure (BP) plus diabetes in the left kidney (below AC). BP above AC increased to 151±8 mmHg 8 wks after AC (n=5, p<0.05 compared to baseline of 108±5 mmHg). To examine the role of endoplasmic reticulum (ER) stress in the development of hypertensive‐diabetic nephropathy, GK‐AC rats were treated with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA, 200 mg/kg/day, IP) from 2 to 8 wks after AC. After 6 wks of treatment, ER stress marker, GRP‐78, was significantly reduced in the right HT kidney compared to the right HT kidney from untreated rats. TUDCA treatment also significantly lowered the BP above the AC (137±7 vs 151±8 mmHg, n=4, p<0.05 compared to untreated group). Glomerular filtration rate in the right HT kidney was increased to 0.99 ml/min/g of kidney weight in the TUDCA treated group compared to 0.67 ml/min/g in the untreated group (n=4, p<0.05). TUDCA treatment for 6 weeks also attenuated renal glomerular injury including thickness of glomerular basement membrane and expansion of mesangial matrix on the right HT kidney. These results suggest that ER stress contributes to kidney injury when HT is imposed on the diabetic kidney. Pharmacological inhibition of ER stress may attenuate increases in BP and kidney injury in hypertensive‐diabetic nephropathy.Grant Funding Source: Supported by NHLBI PO1 HL51971, NIGMS P20GM104357, AHA 14POST18160019
Cyclooxygenases (COX) play a key role in the regulation of renal arterial tone, but not in glomerular function,of mouse with 5/6 nephrectomy (LB725)
Authors: Zhu Bijun , Jin Jianjun , Zhao Zhonghua , Zhang Zhigang , Lu Limin , Zhu Tongyu , Vanhoutte Paul , Shi Yi 
Published: June 2021

Objectives. Hyperfusion induces shear stress, leading to macrovascular endothelial dysfunction. However, effects of hyperfusion on glomerular endothelial cells (microvascular) remain unclear.Methods. C57/BL6 mice were randomly grouped into sham‐operated (2K), 1 kidney removal (1K) and 5/6 nephroectomy groups (5/6K‐off). Renal artery and glomerulus were collected for Western blotting, polymerase chain reaction and immunohistochemistry (IHC) assay.Results. Four weeks after the surgery, arterial blood pressure was comparable among the three groups. Compared with 2K and 1K groups, 5/6K‐off mice had significantly higher levels of renal blood flow. Consistently, relaxations to acetylcholine were blunted in renal arteries, but not in aortae, of 5/6K‐off mice. Indomethacin, a non‐selective cyclooxygenase inhibitor, reduced acetylcholine‐induced relaxation in 2K group, suggesting that prostacyclin is a vasodilator in renal arteries. Indomethacin did not affect acetylcholine‐induced relaxation in 1K mice, but improved it in 5/6K‐off mice. These results indicated that prostanoids, other than prostacyclin, are involved in vasoconstriction. Western blot and IHC experiments confirmed the upregulation of cyclooxygenase‐2 expression in the renal artery of 5/6K‐off mice. Urine protein levels were similar in the three groups, when normalized with remaining glomeruli. Glomerular filtration experiments also indicated that there were no significant increase in levels of macromolecules in 5/6K‐off group. This suggested that mouse glomeruli in 5/6K‐off group have normal function. In addition, Western blotting and IHC experiments did not detect any significant changes in cyclooxygenases expressions in glomeruli.Conclusion. This study presents some intriguing effects of cyclooxygenases in a mouse kidney hyperfusion model. Prostanoids acts as a vasoconstrictor in renal artery of 5/6K‐off mice, but produces a protective effect in 2K group. However, cyclooxygenases are not involved in glomerular function. Further experiments will focus on examining the underlying mechanisms.Grant Funding Source: National Natural Science Foundation of China 81373412
Acetazolamide: an improved treatment for lithium‐induced NDI? (LB726)
Authors: de Groot Theun , Sinke Anne , Kortenoeven Marleen , Baumgarten Ruben , Devuyst Olivier , Loffing Jan , Wetzels Jack , Deen Peter 
Published: June 2021

Lithium causes nephrogenic diabetes insipidus (Li‐NDI) and hydrochlorothiazide (HCTZ) forms, together with amiloride, the mainstay treatment for Li‐NDI patients. Earlier, we found that HCTZ, primarily known for inhibiting the NaCl‐co‐transporter (NCC), also reduces Li‐NDI in NCC knockout mice, coinciding with alkalinized urine, suggesting that inhibition of carbonic anhydrase (CA) by HCTZ plays a role. To test whether CA inhibition is a useful alternative therapy in Li‐NDI, the effect of acetazolamide (ACZ) was tested.Polarized mouse cortical collecting duct (mpkCCD) cells and mice were used to study the effect of ACZ on Li‐NDI.Treatment of mpkCCD cells with ACZ attenuated AQP2 downregulation by lithium. ACZ did, in contrast to amiloride, not affect transcellular voltage. Treatment of Li‐NDI mice with ACZ revealed a significant antidiuresis and increased urine osmolality, which was indifferent from Li‐NDI mice treated with HCTZ/amiloride. However, unlike HCTZ/amiloride, ACZ treatment did not result in hyponatremia, hyperkalemia, hypercalcaemia and metabolic acidosis. Moreover, ACZ rescued AQP2 expression over the entire length of the collecting duct, whereas HCTZ/amiloride only increased AQP2 levels in the renal papilla.In conclusion, our data reveal that ACZ attenuates lithium‐induced downregulation of AQP2 and NDI development. Moreover, as ACZ caused fewer side effects than the conventional treatment, ACZ may represent a better therapeutic agent than HCTZ/amiloride to treat Li‐NDI.Grant Funding Source: Supported by a VICI grant, a RUNMC grant and a grant from the Society of Experimental Laboratory Medicine.
Effect of Deep Brain Stimulation on Sympathetic outflow in humans (LB733)
Authors: Sverrisdottir Yrsa , Green Alexander , Aziz Tipu , Bahuri Nor Faizal , Hyam Jonathan , Basnayake Shanika , Paterson David 
Published: June 2021

Electric deep brain stimulation (DBS) in midbrain nuclei in humans alters cardiovascularparameters, presumably by modulating autonomic and baroreflex function. Baroreflex modulation of sympathetic outflow is crucial for cardiovascular regulation and is hypothesized to occur at two distinct brain locations. This study aimed to evaluate sympathetic outflow in humans with DBS electrodes during ON and OFF stimulation of specific midbrain nuclei known to regulate cardiovascular function.Muscle sympathetic nerve activity (MSNA) was recorded during DBS ON and OFF in patients with chronic neuropathic pain (n=7) and Parkinson’s disease (n=10). Arterial blood pressure (ABP), heart rate and respiration were monitored during the recording session and spontaneous vasomotor and cardiac baroreflex sensitivity (BRS) were assessed. Head‐up tilt testing was performed separately in the Parkinson’s patients post‐operatively.Stimulation of the dorsal most part of the subthalamic nucleus (STN) and ventrolateral periaqueductal gray (PAG) resulted in improved vasomotor BRS, decreased MSNA burst frequency and ABP, unchanged burst amplitude distribution and a reduced fall in ABP after tilt. Stimulation of the dorsolateral PAG resulted in a shift in burst amplitude distribution towards larger amplitudes, decreased spontaneous BP variability and unchanged burst frequency, BRS and ABP.Baroreflex regulation of sympathetic outflow occurs in the STN and PAG. Our results may have implications in understanding abnormal sympathetic discharge in cardiovascular disease and provide an opportunity for therapeutic targeting.Grant Funding Source: supported by, BHF, NIHR BRC
The traditional herbal medicine, Ge‐Gen‐Tang, inhibits pacemaker potentials by nitric oxide/cGMP dependent ATP‐sensitive K+ channels in cultured interstitial cells of Cajal from the mouse small intestine (LB746)
Authors: Kim Byung Joo 
Published: June 2021

Interstitial cells of Cajal (ICCs) are pacemaker cells that activate the periodic spontaneous depolarization (pacemaker potentials) responsible for the production of slow waves in gastrointestinal (GI) smooth muscle. The effects of Ge‐Gen‐Tang (GGT), a traditional herbal medicine, on pacemaker potentials in cultured ICCs from the mouse small intestine were investigated. The patch‐clamp technique for whole‐cell recording was used in cultured ICCs. Under the current clamping mode, ICC generated pacemaker potentials. The resting membrane potential was ‐ 52 4 mV and the amplitude was 18.3 1.6 mV. GGT (10‐50 mg/ml) decreased the frequency and amplitude of pacemaker potentials in a concentration‐dependent manner, but had no effects on membrane potentials. In the presence of 50 mg/ml GGT, the amplitude was 1.2 0.3 mV and the frequency was 0.3 0.6 cycles/min at 50 mg/ml. However, these effects were blocked by intracellular GDPβS, a G‐protein inhibitor, and glibenclamide, a specific ATP‐sensitive K+ channels blocker. Pretreatment with SQ‐22536, an inhibitor of adenylate cyclase, before the application of GGT had no effect on pacemaker potentials. Similarly, pretreatment with ODQ, an inhibitor of guanylate cyclase, did not inhibit the pacemaker potentials. However, GGT inhibited the pacemaker potentials in the presence of SQ‐22536, not in ODQ. The amplitude was 1.7 0.6 mV in the presence of SQ‐22536 and 17.1 2.6 mV in ODQ at GGT 50 mg/ml. Also, pretreatment with L‐NAME (an inhibitor of nitric oxide (NO) synthase) before the application of GGT abolished its effects on pacemaker potentials, but L‐NAME itself had no effect. In the presence of L‐NAME, the amplitude was 18.7 0.6 mV at GGT 50 mg/ml. Taken together, GGT inhibits pacemaker potentials in ICC in a G protein‐, cGMP‐ and NO‐dependent manner. Our data suggest that the gastroprokinetic effects of GGT are mediated by the induction of pacemaker potentials in ICCs.Grant Funding Source: Supported by the Traditonal Korean Medicine R&D Project, Ministry of Health & Welfare, Republic of Korea (HI12C1886, B120008)
Evaluation of Cathepsins (K, L and S) expression during 3T3‐L1 differentiation (LB757)
Authors: Prado‐Palma Renata , Christoffolete Marcelo 
Published: June 2021

Objectives: Obesity is a crescent global disease that can trigger type II diabetes, cardiovascular disease and many others health problems. Obesity is characterized by white adipose tissue (WAT) accumulation. Adipocytes proliferate via pre‐adipocytes differentiation, which comprehends a well orchestraded sequence of events. Therefore, adipocyte differentiation is key step in development of obesity. Cathepsins play an important role on WAT differentiation, evidenced by the reduction of WAT in Cathepsin K or L KO mice. The objective of this study is to evaluate the expression of Cathepsins K, L and S (CatK, CatL and CatS) during the course of adipocyte differentiation. Methods: 3T3‐L1 cell culture was differentiated according to standard protocol, after 2 days of confluence cells were tretated with differentiation cocktail (isobutilmetylxantine, dexamethazone and rosiglitazone), and differentiation followed for additional 8 days. Cells were harvested at 0, 2, 4, 6, 8 and 10 days time points of differentiation. Total RNA was obtained by Trizol and submitted to RT‐real time PCR. Expression of differentiation marker (ap2/FABP4), later regulators (C/EBPα and PPARγ2) and CatK, CatL and S were evaluated. Results: Cathepsin L is expressed at very high levels in 3T3‐L1 cells, followed by a high level expression of CatK. CatS is expressed at very low levels in 3T3‐L1 cells, when compared to the other Cathepsins. CatK has a steady expression troughout differentiation except for a 2.5 fold increased expression at Day 2. The CatL was not modulated by differentiation. CatS is very poorly expressed in 3T3‐L1, however Day 2 and Day 10 showed 10 fold higher levels when compared to Day 0. Conclusion: Cathepsins are expressed in 3T3‐L1 cells similarly to WAT. The peak expression of CatK and CatS on Day 2 suggests a possible role in the early stages of adipocytes differentiation.Financial Support: FAPESP (2008/10700‐1); UFABC.Grant Funding Source: FAPESP, UFABC
MiR‐17~92 promotes hypoxia‐induced pulmonary hypertension by regulating proliferation and contraction of pulmonary arterial smooth muscle cells (LB779)
Authors: Zhou Guofei , Chen Tianji , Zhou Qiyuan , Tang Haiyang , Yuan Jason , Raj J Usha 
Published: June 2021

Introduction: Recent studies suggest that microRNAs (miRNAs) play important roles in development and pathogenesis of human diseases. We sought to identify novel miRNAs that may be involved in the pathogenesis of pulmonary arterial hypertension (PAH) and to investigate underlying mechanisms.Methods and Results: We performed miRNA qPCR array using pulmonary arterial smooth muscle cells (PASMC) isolated from lungs of normal donor and PAH patients. We found that all of the six members of the miR‐17~92 cluster were down‐regulated in PAH PASMCs. In hypoxia‐induced PAH mouse model and cultured human PASMCs, we found that short term hypoxia induced miR‐17~92 whereas prolonged hypoxia suppressed miR‐17~92. We generated a strain of SMC‐specific miR‐17~92 knockout (sm‐17~92‐/‐) mouse by crossbreeding miR‐17~92 fl/fl mice with sm22α‐Cre mice and subsequent backcrossing. We exposed 8‐10 week old sm‐17~92‐/‐ mice along with their wild type littermates to hypoxia (10% O2) or normoxia for five weeks. We showed that knockout of miR‐17~92 in SMC attenuated hypoxia‐induced increase in measured their right ventricular systolic pressure (RVSP), RV hypertrophy (RV/(LV+S) ratio), and pulmonary arterial wall thickness, suggesting that SMC‐specific miR‐17~92 is essential for the development of PAH. To investigate the underlying mechanism, we over‐expressed the miR‐17~92 cluster in human PASMC by a lenti‐virus encoding this miRNA cluster. Overexpression of mi‐17~92 induced expression levels of SMA, SM22α, Calponin, and PCNA and BrdU incorporation. Human PASMC from idiopathic PAH (IPAH) patients expressed decreased levels of SMA, SM22α, and Calponin, whereas over‐expression of miR‐17~92 restored the expression of SMA, SM22α, and Calponin in PASMCs from IPAH patient.Summary: We provide evidence that miR‐17~92 is dysregulated in hypertensive PASMC and suppression miR‐17~92 in SMC is sufficient to inhibit hypoxia‐induced PAH in vivo. We also show that miR‐17~92 induces PASMC proliferation and expression of contractile proteins. These results suggest that miR‐17~92 may promote PAH by regulating vascular remodeling and that miR‐17~92 may represent a novel therapeutic target for the treatment of PAH. Support: NIH HL110829 and Gilead Sciences Research Scholars Program.Grant Funding Source: Support by NIH HL110829 and Gilead Sciences Research Scholars Program.
Connexin 43 mediates LPS‐induced permeability in lung microvascular endothelial cells (LB785)
Authors: Alli Shanta , Manna Jayeeta , Parthasarathi Kaushik 
Published: June 2021

Increased microvessel permeability is a major characteristic of lung inflammation. We showed inhibiting connexin 43 (Cx43)‐containing gap junctions blunts permeability increases in microvessels due to an inflammatory insult. However, it is unclear whether Cx43 levels directly influence the lung endothelial barrier. Toward this, we cultured rat lung microvascular endothelial cells (RLMVEC) on transwell inserts and determined permeability via flux of FITC dextran 40 kd (FDx40) across the endothelial monolayer. In vehicle‐treated monolayers, FDx40 fluorescence in the bottom chamber was 92±2 gray levels (mean±SEM; n=3; measurements in duplicate). Treating RLMVEC with LPS (100 ng/ml) for 4 hours increased FDx40 permeability to 99±3 gray levels. To determine responses to reductions in Cx43 levels, we treated RLMVEC monolayers with Cx43 shRNA lentiviral vector for 24 hours. FDx40 permeability in Cx43 shRNA‐treated monolayers was 13% lower than control shRNA‐treated cells. Further, LPS‐treatment of Cx43 shRNA‐treated monolayers induced a more than 27% decrease in permeability compared to control (P<0.05). To determine responses to elevated levels of Cx43, we transfected RLMVEC monolayers with Cx43‐cDNA. FDx40 permeability in Cx43 cDNA‐treated monolayers was 76% higher than control cDNA‐treated monolayers. Further, LPS‐treatment of Cx43 cDNA‐treated monolayers induced a more than 45% increase in permeability compared to control. Together, these data show for the first time that reduction and increase in Cx43 levels,respectively blunts and augments endothelial monolayer permeability. Thus we interpret, endothelial Cx43 levels directly influence endothelial barrier leak.Grant Funding Source: HL75503
Regulation of Adrenaline Synthesis by Intermittent Hypoxia (LB793)
Authors: Khurana Sandhya , Venkataraman Krishnan , McDonald Erika , Yao Jiefei , Studer‐Rabeler Karen , Tai T.C. 
Published: June 2021

Epidemiological studies show a strong correlation between Obstructive Sleep Apnea (OSA) and cardiovascular disorders. OSA patients experience intermittent hypoxia (IH), characterized by brief, but recurring episodes of cessation in breathing. These patients have higher levels of circulating catecholamines and an increased incidence of hypertension; however the mechanisms defining this association are not clearly established. Genetic linkage studies have associated the phenylethanolamine N‐methyltransferase (PNMT) gene to the development of hypertension. PNMT, the terminal enzyme in the catecholamine biosynthetic pathway, directly responsible for adrenaline synthesis, is elevated in hypertensive animals. Recent studies utilizing PC12 cells show an increase in the expression of PNMT and its regulatory transcription factors when exposed to continuous hypoxia. The current study examined the regulation of PNMT under conditions of intermittent hypoxia. The mRNA of PNMT was analyzed to assess if the regulation of PNMT expression entails alternative splicing. The mRNA and protein levels of the transcription factors HIF1α, Egr‐1, GR, and Sp1, was analyzed to assess the cellular pathways involved in regulating PNMT expression. A PNMT promoter‐driven luciferase assay was performed to evaluate promoter activity under IH. Preliminary results lay an antecedent for the regulation of PNMT by IH conceivably via an altered regulation of its transcription factors and establish a possible role for PNMT in IH mediated hypertension in OSA patients.Grant Funding Source: Supported by NSERC
Mitochondrial ROS Amplify Nox2 Signaling and Atrophy in the Rat Soleus with 7 Days of Hindlimb Unloading (LB821)
Authors: Lawler John , Lee Yang , Hord Jeff , Guzzoni Vinicius , Kuczmarski J 
Published: June 2021

Removal of mechanical loading during spaceflight, bedrest, or immobilization causes rapid and profound atrophy of skeletal muscle. Emerging data suggest that oxidative stress from mitochondrial sources may contribute to unloading‐induced skeletal muscle atrophy. We recently found that the Nox2 isoform of NADPH oxidase is also upregulated in the unloaded soleus muscle, associated with FoxO3a activation and fiber atrophy. We used a mitochondrial specific antioxidant peptide (SS‐31) to test the hypothesis that mitochondrial ROS are involved in feed‐forward or amplification signaling with Nox2 in response to mechanical unloading of the rat soleus muscle. F344 rats were divided (n=7/grp) into the following groups: ambulatory control (CON), ambulatory + SS‐31 (1.5 mg/kg/d) (AS), hindlimb unloaded for 7 days (HU), and HU + SS‐31 (HUS). SS‐31 significantly attenuated the reduction in soleus mass and soleus mass/body mass ratio elicited by HU. SS‐31 also abrogated an increase in Type II fibers during unloading. In addition, SS‐31 significantly blunted upregulation of Nox2 subunit p67phox in the unloaded soleus, using fluorescent signal intensity and p67phox membrane localization as markers. Our results are consistent with the postulate that mechanical unloading of skeletal muscle causes mitochondrial ROS to upregulate Nox2 and thus drive atrophy and fiber‐type shift from slow to fast. Supported by NASA (NNX13AE45G), NIH (AR054084), and the Huffines Institute.Grant Funding Source: NASA
Effects of capsaicin on tension in the slow skeletal muscle fibers of the chicken (LB823)
Authors: Uribe Calvillo tannia , Trujillo Xóchitl , Montoya‐Perez Rocío , Sánchez‐Duarte Elizabeth , Huerta Miguel 
Published: June 2021

Skeletal muscle possesses two types of muscle fibers: 1) fast and 2) slow or tonic. In skeletal muscle fibers exists evidence of vanilloid receptors presence. It is known that vanilloid receptor TRPV1 is activated by capsaicin. On the other hand, primary sensitive neurons from chicks the vanilloid receptors are capsaicin‐insensitive.By using isometric recording in bundles of the slow skeletal muscle fibers of one or two‐week age chicken dissected from the anterior latissimus dorsi muscle, the effect of capsaicin (10 μM) on caffeine (6 mM) evoked contractures was measured in the presence and absence of the antagonist capsazepine (1 μM). Capsaicin diminished maximum tension in the slow skeletal muscle fibers until 83.25±11.5%, (n=7, p=0.002) respecting to control, an effect that was partially reverted in the presence of the TRPV1 antagonist capsazepine. However, this reduction of maximum tension was not statistically significative (mean was 91.30±5.04%, n=5, p>0.05). These results suggest capsaicin is capable to activate the vanilloid receptor in avian skeletal muscle fibers.Grant Funding Source: CIC2014‐RMP