bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic Nicotine (NIC) Aggravates Sub Pressor Angiotensin II (SP‐AngII)‐Induced Renal and Cardiac Disease
Authors: Chandrashekar Kiran , Maranon Rodrigo O , Soljancic Andrea , Lopez-Ruiz Arnaldo , Arany Istvan , Liu Ruisheng , Juncos Luis A
Published: June 2021

Smoking and hypertension (HTN) are risk factors for development and progression of cardiac and renal disease. NIC is a key factor propagating the deleterious effects of smoking. We examined the interaction between NIC and SP‐AngII‐induced HTN, renal injury and cardiac stress. Male SD rats were pretreated 12 days with NIC (12.5μg/ml) or vehicle (saccharine 2%) in drinking water, and randomized to get either saline (Cont) or SP‐AngII (200ng/kg/min) by SQ minipumps, while continuing to receive saccharine or NIC for an additional 22 days. The various parameters of renal injury and cardiac stress were assessed. NIC itself did not alter blood pressure but caused a mild (~5mmHg) elevation of SP‐AngII‐induced HTN that only became apparent at day 17.

Renal
Cardiac

PlCreat mg/dl
KIM‐1 pg/μg
TNF Alfa (pg/ml)
HO‐1 level ng/ml
LVH gms
BNP ng/μg
TNF‐Alfa (pg/ml)
HO‐1 level ng/ml

Cont
0.4±0.1
58±5
1.2±0.5
0.6±0.02
0.56±0.03
0.17±0.02
8.4±0.5
0.7±0.1

NIC
0.6±0.1
253±9*
6.4±1*
4±1*
0.49±0.1
0.19±0.04
38.2±1*
3.3±0.1*

Sp‐AngII
1.2±0.14†
537±76†
14.5±2†
14.3±2†
0.77±0.03†
4.5±0.6†
197.5±28†
12.2±2.1†

Sp‐AngII + NIC
1.8±0.1#†
874±68#†
28.5±3#†
21.2±2#†
1.1±0.2#†
6±0.7#†
259±38#†
19.1±1.3 #†

p< 0.05: * vs. Veh; # vs. SP‐AngII; † vs. NIC

NIC exacerbated SP‐AngII induced renal injury and cardiac stress to a level not commiserate with the rise in HTN, suggesting that NIC may have a direct effect on SP‐AngII induced renal and cardiac injury.
anti‐mouse renin expression in the rat kidney
Authors: Hurley Mary , Apenteng Enez , Tyrpak Stephen , DenHaese Jason , Olivieri Marion
Published: June 2021

The causes of toxemia of pregnancy are not fully understood. This project examines rat kidneys to determine if a mouse anti‐renin antibody will cross‐react rat renin‐producing cells in the rat. This will allow further study female reproductive tissues in the rat to examine for renin production. Renin is known as hormone produced by the juxtaglomerular cells of the afferent arteriole of the kidney in response low blood pressure. Also, renin is an immediate downstream target of Class I Hox gene regulation, important in embryonic development. In mice, renin is expressed in embryonic renal, adrenal and gonadal arteries, the adrenal glands, and tissue associated with embryonic pronephric and mesonephric kidneys. Using a renin/GFP reporter in transgenic mice, renin is expressed in placental giant trophoblast cells and uterine/ovarian artery cells of the tunica adventitia. In RCS rats, renin antibody stain that used anti‐rat renin and peroxidase labeled placental giant trophoblast cells and cells of the tunica adventitia of the uterine/ovarian artery. This project examines rat kidney tissue labeled by indirect immuno‐fluorescence with anti‐mouse renin antibody and fluorescent conjugate. Cells in the juxtaglomerular region of the kidney were renin positive. This demonstrates that anti‐mouse renin antibody can dependably label regions in the rat kidney that are known for renin production. This will allow for further studies to determine renin location in rat female reproductive tissues. Dr. Craig Jones of Roswell Park Cancer Institute generously donated mouse renin antibody and lab space for stain procedures. D'Youville College Faculty Council and Department of Math & Natural Sciences supported work.
Bradykinin B2 receptor (B2R) increases renin expression and release in cortical collecting duct M‐1 cells
Authors: da Silva Lara Lucienne , Bourgeois Camille RT , El-Dahr Samir S , Prieto Minolfa C
Published: June 2021

The coexistence of the kalikrein‐kinin system (KKS) and the rennin‐angiotensin system (RAS) in the connecting tubules and cortical and medullary collecting ducts of kidneys provides basis for the regulation of blood pressure. In the present study, using an established cortical collecting duct (M‐1) cell line and treatment with different concentrations of bradykinin (BK; 10−14 to 10−6M) we determined the role of the B2R activation on the regulation of renin. BK increased renin transcript and protein levels in a dose‐dependent manner, with a maximum effect at 10−10M; which paralleled the 3x increase in renin content in the cell culture media. To further identify the signaling pathway activated by the B2R‐mediated stimulation of collecting duct CD renin expression and secretion, we used the B2R antagonist, HOE 140; calphostin C, a PKC inhibitor; H89, a PKA inhibitor and L‐NAME, a NO synthase inhibitor. These experiments revealed that the activation of B2R stimulated renin synthesis in M‐1 cells by increasing cGMP levels (87%) independently of PKA. HOE 140 (10−8M), Calphostin C (10− 6M) and L‐NAME (10−7M) completely abolished the BK–mediated stimulation of renin. Altogether, these data indicate that B2R activation is required for the full expression and secretion of renin by the collecting duct cells, via a mechanism that involves two synergic pathways: the Gq protein/PKC and the NO/cGMP.
Chronic parathyroid hormone‐related protein induces hypercalcemia and increases plasma renin activity
Authors: Atchison Douglas K , Westrick Elizabeth , Szandzik David L , Beierwaltes William H
Published: June 2021

Parathyroid hormone‐related protein (PTHrP) increases renin release from isolated perfused kidneys, but its effects on renin in vivo are unknown. In vivo, PTHrP causes hypercalcemia, weight loss and polyuria, all of which may affect renin. We hypothesized that chronically elevated PTHrP would increase plasma renin activity (PRA) by reducing salt and caloric intake. We infused male Sprague‐Dawley rats with vehicle or PTHrP via subcutaneous osmotic‐mini pumps for 5 days. PTHrP increased PRA from 3.6±0.7 to 14.9±8.2 ng Ang I/ml/hr (p<0.05), increased plasma calcium from 13.1±0.06 to 17.6±0.08 mg/dl (p<0.05), decreased body weight from 263 to 220 g (p<0.05) and caused polyuria (control: 14.5±2.6 vs. PTHrP: 34.5±6.5 ml urine/24 hrs, p<0.05). To attenuate the PTHrP‐induced anorexia, we gave PTHrP‐treated rats dietary caloric supplementation which attenuated the weight loss and decreased PTHrP‐stimulated PRA from 19.5±5.8 to 5.9±1.3 ng Ang I/ml/hr, but did not affect the hypercalcemia nor polyuria. Our data suggests chronically elevated PTHrP increases PRA, not via a calcium effect but possibly via its anorexic effects on salt and caloric homeostasis. Funded by 5F30DK084654‐03 and 5P01HL090550‐03.
Interaction between Ang1–7 (‘ Mas’) and AT1 receptors in regulating renal sodium and water excretion
Authors: o neill julie anna , Johns Edward J
Published: June 2021

Ang (1–7) has natriuretic and diuretic actions at the kidney but the underlying mechanisms are unclear. This study aimed to determine if Ang (1–7) induced increases in sodium and water excretion were solely dependant upon intrarenal (IR) Mas receptor activation or whether Ang II induced IR AT1 receptor stimulation was required. Male Wistar rats (n= 6–7) were anaesthetized (chloralose/urethane) and prepared for mean arterial pressure (MAP) and left renal function measurement and IR infusion of saline and drugs. Data ±SEM were subjected to a Students t‐test and significance set at (P<0.05). MAP was 101±3mmHg, Fractional Sodium Excretion (FENa) was 1.5±0.3% and Urine Volume was 52.4± 14.3μL/min/Kg. Ang (1–7) had no effect on MAP but increased FENa by 206% and UV by 150% (both P<0.05). In the presence of either ‘Mas’ receptor (A‐779) or AT1 receptor (Losartan) antagonists, Ang (1–7) only increased FENa by 21% and 19% respectively and UV by 16% and 6% respectively, significantly less than in the absence of both antagonists. These data indicate that there is an interaction between IR ‘Mas’ and AT1 receptors which appears to be necessary to fully mediate the actions of Ang (1–7).
Differential effects of ACE and chymase in the metabolism of exogenous angiotensin‐(1–12) in Wistar‐Kyoto rats
Authors: Moniwa Norihito , Varagic Jasmina , Ahmad Sarfaraz , Ferrario Carlos M.
Published: June 2021

We examined whether angiotensin converting enzyme (ACE) or chymase is involved in the processing of angiotensin‐(1–12) [Ang‐(1–12)] in the circulation of 15 male anesthetized Wister‐Kyoto rats (WKY) at age 12–13 weeks. Rats were assigned to vehicle (Veh, saline, n=6), lisinopril (Lis, 10mg/kg, n=5) or chymostatin (10mg/kg, n=4). The saline Veh or Lis were infused intravenously 15 min prior to the administration of Ang‐(1–12) while the chymase inhibitor was administered intraperitoneally 30 min prior to Ang‐(1–12). Plasma Ang‐(1–12), Ang I, Ang II, and Ang‐(1–7) levels were measured by RIA. Peak plasma Ang‐(1–12) levels at 15 min following initiation of the infusion were not statistically different among the three treated groups while in Lis‐treated rats plasma Ang I levels rose to 3.1 versus 1.6 pmol/mL in Veh and plasma Ang II decreased to 0.3 compared with 15.2 pmol/mL in Veh. Although inhibition of chymase had no significant effect on plasma levels of Ang I and Ang II, peak concentrations of circulating Ang‐(1–7) rose to 0.75 compared with 0.43 and 0.47 pmol/mL in Veh and Lis‐treated WKY, respectively (p < 0.05). We conclude that angiotensin converting enzyme acts as the primary source for the conversion of Ang‐(1–12) in the circulation of WKY and also show for the first time a role for chymase in Ang‐(1–7) production from Ang‐(1–12).

This research was supported by PO1 HL 051952.
Effects of combination therapy with valsartan and aliskiren on arterial pressure, cardiac hypertrophy and urinary protein excretion in hypertensive rats
Authors: Moniwa Norihito , Varagic Jasmina , Ahmad Sarfaraz , Ferrario Carlos M.
Published: June 2021

We examined the effect of valsartan and aliskiren in 29 (12‐wk. old) male congenic mRen2. Lewis hypertensive rats following assignment to: vehicle (n=9), valsartan (30mg/kg/day; n=10) or valsartan combined with aliskiren (50mg/kg/day; n=10). Arterial pressure (AP) was measured by telemetry and concentrations of angiotensin‐(1–12) [Ang‐(1–12)], Ang II and Ang‐(1–7) in plasma, left ventricle (LV), kidney cortex and urine were measured by RIA 2 weeks after. Urinary angiotensinogen (U‐AGT) was measured by ELISA. Mean AP, LV weight and U‐protein excretion (UP) were reduced by valsartan and further reduced by the combined therapy. The increases in plasma Ang II induced with valsartan were reversed by the addition of aliskiren. Renal (R‐) Ang II was decreased and R‐Ang‐(1–7)/R‐Ang II ratio was increased in both treatment groups. UP correlated positively with R‐Ang II and negatively with R‐Ang‐(1–7)/R‐Ang II ratio while the reductions in U‐AGT and U‐Ang‐(1–12) in both treatment groups correlated with each other. We conclude that the more pronounced response induced by combined therapy is mediated in part through the blockade of renin and consequent decrease in Ang II levels. The changes of R‐Ang II or R‐Ang‐(1–7)/R‐Ang II ratio may explain the antiproteinuric effect of the combined therapy.

This research was supported by PO1 HL 051952.
Development of a radioligand for angiotensin‐converting enzyme‐2 (ACE‐2)
Authors: Speth Robert C , Grobe Nadja , Santos Kira L. , Swindle Jamala D. , Morris Mariana , Lazartigues Eric
Published: June 2021

The ACE‐2/angiotensin 1–7/Mas axis antagonizes many pathophysiological effects of the classical renin angiotensin system. There is considerable interest in measuring ACE‐2 and determining its tissue localization. Toward this end we have developed a small molecule ACE‐2 inhibitor that can be radioiodinated to assess the localization of ACE‐2 by in vitro autoradiography. This ACE‐2 inhibitor reduced metabolism of the synthetic ACE‐2 substrate Mca‐APK(Dnp) in the micromolar range. The ACE‐2 inhibitor was radioiodinated using the chloramine T procedure and the mono125I‐ACE‐2 inhibitor was purified by reverse phase HPLC. The radioligand displayed saturable binding to rat kidney homogenate that was displaceable by EDTA (10 mM). The radioligand (50 pM) was incubated with 20 micron –thick coronal sections of mouse brain in the presence of captopril (1 μM) with or without the peptidic human ACE‐2 inhibitor DX‐600 (1.3 μM). An alternate set of sections was incubated with captopril (1 μM) and EDTA. There was a diffuse pattern of 125I‐labeled ACE‐2 inhibitor binding throughout the mouse brain. Binding in the presence to DX‐600 was only moderately decreased, however, it was almost completely eliminated in the presence of EDTA. These results indicate the utility of a radioiodinated ACE‐2 inhibitor for characterization and localization of ACE‐2. Supported in part by JFS Sales and Consulting, LLC.
The effect of Helicobacter typhlonius infection on colonic ion transport in the IL10 knockout mice
Authors: Lindstrom Anna , Fan Shujun , Schultz Michael , Butt Grant
Published: June 2021

Helicobacter infection causes severe colitis in immunocompromised mice, but little is know of its effects on the properties of the colonic epithelium. We compared the effects of H. typhlonius infection on the functional properties of the proximal (PC) and distal colon (DC) of wildtype (WT) and IL10 knockout (IL10−/−) mice. WT mice showed no clinical effects of infection, colonic inflammation or changes in functional properties of the colon. Other than a slight increase in water content of the stool, IL10−/− mice also showed no clinical effects of infection. Despite this the PC was severely inflamed, with a milder inflammation in the DC. There was no increase in TNFα or INFγ associated with the inflammation, but IL12p40 levels were increased. Unexpectedly, the conductance (GT) of the PC was decreased, as was the permeability. No change in GT of the DC occurred. Associated with infection was a reduction in the spontaneous short circuit current (Isc) in the PC but not the DC. Also, in the PC of infected animals the forskolin‐stimulated Isc was only ≈5% of that of non‐infected controls, whereas the response of the DC was ≈50% of that of controls. In contrast, in infected animals the carbachol‐stimulated Isc was essentially eliminated in both the PC and DC. As seen in other inflammatory models colonic inflammation associated with H. typhlonius infection of IL10−/− mice markedly alters the transport properties of the colon, however this does not result in diarrhea. This may be a consequence of the absence of a change in colonic permeability or distal sparing due to the limited inflammation in the distal colon. Supported by the University of Otago.
Duox‐a novel antimicrobial duodenal defense mechanism
Authors: Higashiya Masaaki , Akiba Yasutada , Rudenkyy Sergiv , Guth Paul H , Engel Eli , Kaunitz Jonathan D
Published: June 2021

Antimicrobial defense mechanisms are necessary to maintain relative foregut sterility. We hypothesized that dual oxidase (Duox), a H2O2 generating system in airway, is also present in duodenum, and that Duox‐generated H2O2 activates cytosolic phospholipase A2 (cPLA2) in the prostaglandin (PG) synthesis. We measured duodenal HCO3− secretion (DBS) with pH and CO2 electrodes in the perfused duodenum of anesthetized rats. ATP or pH 2.2 acid was luminally perfused +/− NADPH oxidase inhibitor DPI or VAS2870, P2Y receptor antagonist suramin, cPLA2 inhibitor OBAA, or indomethacin pretreatment (IND). H2O2 in the perfusate was measured with Amplex Red; ATP using bioluminescence. Duox2 and its chaperone DuoxA2 were expressed on the duodenal villous brush border. Acid exposure increased DBS with releasing ATP and H2O2. DPI or VAS2870 inhibited DBS and H2O2 output without affecting ATP release. Luminal ATP increased DBS and H2O2 output, both inhibited by DPI or suramin. IND or OBAA inhibited ATP‐induced DBS without affecting H2O2 output. H2O2 exposure stimulated DBS. Luminal acid increases ATP release, increasing intracellular Ca2+ via P2Y receptor activation, then activates Duox2, generating H2O2. Luminal H2O2 activates cPLA2, increasing PG production, then stimulates DBS. The ATP‐P2Y‐Duox pathway generates antimicrobial luminal H2O2 while increasing acid‐neutralizing DBS. VA Merit Review, NIH R01 DK54221
Intestinal divalent metal‐ion transporter‐1 is critical for iron homeostasis but is not required for maintenance of Cu or Zn
Authors: Shawki Ali , Anthony Sarah R , Nose Yasuhiro , De Renshaw Tomasa Barrientos , Thiele Dennis J , Mackenzie Bryan
Published: June 2021

Divalent metal‐ion transporter‐1 (DMT1)—the product of the SLC11A2 gene—is a widely‐expressed iron transporter that serves intestinal iron absorption and erythroid iron utilization. Whereas DMT1 exhibits reactivity with a broad range of transition metal ions, questions have arisen as to the role that DMT1 plays in the absorption of Cu and Zn. We tested the hypothesis that DMT1 is essential for the absorption of Fe, Cu, Mn, and Zn by examining hematological parameters, iron status, and tissue metal content in a mouse model lacking intestinal DMT1 (i.e. DMT1int/int) at age ≈ 120 days. Generation of the DMT1int/int model, by crossing floxed DMT1 and villin‐Cre transgenic lines, was described previously [Gunshin et al (2005) J. Clin. Invest. 115, 1258–1266]. The DMT1int/int mouse exhibited a severe microcytic, hypochromic anemia—characterized by profound decreases in hematocrit (DMT1int/int, 7% ± SD 2% cf. wildtype, 44% ± 4%; n = 7–9), hemoglobin concentration, mean corpuscular volume, and serum iron— accompanied by cardiac hypertrophy, splenomegaly, and severely depleted nonheme iron stores (liver, spleen). Intraperitoneal iron injection corrected the iron‐deficiency anemia phenotype of the DMT1int/int mouse. Analysis of tissue metal content by using ICP–MS revealed strikingly decreased Fe levels in spleen, liver, heart and kidney in DMT1int/int compared with wildtype mice. Mn content was modestly decreased in kidney and spleen but not in other tissues. We observed no changes in tissue Zn or Cu levels, except for a modest increase in spleen Cu content. Our data indicate that intestinal DMT1 is critical for iron homeostasis but is not required for maintenance of Cu or Zn status.
Expression of a MAPEG GST from Leishmania tarentolae
Authors: Osei-Owusu Nana Yaw , Hearne Jennifer , Currington Rashaila
Published: June 2021

Leishmaniasis is a tropical disease that afflicts approximately 12 million of the world's population. It causative agent is the protozoa Leishmania, a member of the Trypanosomatidea family. Trypanosomes lack a complete heme biosynthetic pathway; therefore, they must acquire heme exogenously. Its mechanism of heme scavenging is unclear. One way of heme acquisition may be accomplished through the coordination of heme with GSH via MAPEG, members of the GST superfamily. We know that Macaca fascicularis microsomal prostaglandin E synthase type 2, a MAPEG GST, binds GSH which forms a coordination bond with heme. We hypothesized that there is an enzyme similar to mPGES‐ 2 which scavenges heme in Leishmania. We then identified the first GST member gene, resembling mPGES‐2, in Leishmania. Identification of the target gene in the L. major genome was accomplished using BLAST at GeneDB. Amplified homolog in L. tarentolae was ligated with the pCR8⁄GW⁄TOPO TA vector for recombination with pDEST14 to generate an expression vector. Since Leishmania lack a complete heme biosynthetic pathway, exploitation of its heme dependency is a key target for drug discovery
Cyclosporin A, but not FK506 induces osmotic lysis of pancreas zymogen granules (ZG), intra‐acinar enzyme release and lysosome instability by activating a K+ channel
Authors: Thevenod Frank , Lee Wing-Kee , Braun Matthias , Langelüddecke Christian
Published: June 2021

The immunosuppressant tacrolimus (FK506) has improved pancreas allograft survival compared to cyclosporin A (CsA), possibly due to reduced acute pancreatitis following ischemia‐reperfusion injury. Ion permeabilities in zymogen granules (ZG) membranes, including a KCNQ1 K+ channel, promote hormone‐stimulated enzyme secretion. We investigated whether a differential modulation of ZG and lysosomal ion permeabilities, and enzyme secretion by CsA/FK506 contributes to pancreatitis. Rat ZG and lysosomes were isolated by gradient centrifugation, ion permeabilities assayed by osmotic lysis, and single channel currents recorded in a planar lipid bilayer. Amylase release was measured in permeabilized acini and lysosomal cathepsin B release detected by immunoblotting. CsA (1–10μM), but not FK506, enhanced ZG osmotic lysis by selectively increasing K+ permeability up to 5‐fold. ZG membrane K+ channels showed ~2‐fold increased single channel open probability with CsA only. CsA selectively increased basal (~2‐fold), but not cholecystokinin‐octapeptide (1nM)‐induced amylase secretion in K+ medium only. CsA (5μM), but not FK506, increased cathepsin B release from lysosomes. CsA selectively opens the ZG K+channel and induces cathepsin B release from lysosomes, which cause increased in situ lysis of ZG and may induce or aggravate acute allograft pancreatitis. Funded by Mukoviszidose e.V. (F 04/04) and DFG TH 345/11‐1.
Purinergic regulation of ion transport in Capan‐1 cell monolayers
Authors: Wang Jing , Novak Ivana
Published: June 2021

The aim of the present study was to develop a human pancreatic duct model and elucidate the purinergic signaling regulation of ion transport in pancreatic ducts. Human pancreatic duct cells, capan‐1 were grown on permeable supports. Transepithelial potential (Vte) was measured in open‐circuit Ussing chamber in physiological buffers. Capan‐1 cells formed monolayers with resting transepithelial resistance 404±25 Ω·cm2 (n=35). Serosal ATP (100 μM) transiently increased Vte from −1.4±0.2 to −4.7±0.4 mV and short‐circuit current (Isc) by 14± 0.8 μA/cm2, while mucosal ATP increased Vte by −3.6±0.3 mV and Isc by 13±1 μA/cm2 (n=28). The Ca2+‐activated Cl− channel (CaCC) blocker niflumic acid (NA, mucosa, 100 μM, n=5) inhibited 44% of mucosal but not serosal ATP effect. The CFTR Cl− channel blocker CFTRinh172 blocked both mucosal and serosal ATP effects (mucosa,10 μM, n=5). The intermediate conductance K+ (IK) channel opener DCEBIO (mucosa, 100 μM, n=5) increased mucosal ATP effect, and DCEBIO stimulation was completely inhibited by NA and CFTRinh172 (n=8). The IK channel blocker, clotrimazole, abolished mucosal and serosal ATP effects (30 μM, n=6). In conclusion, mucosal ATP opens both CFTR and CaCC and may stimulate pancrea secretion, while serosal ATP regulates secretion partly through CFTR. In addition, ATP stimulation also regulates IK channels that provide the driving force for Cl− channel dependent secretions.
Islet dysfunction in rats fed a high fat diet (HFD): A structurefunction study
Authors: Sweazea Karen L , Brower Jeremy , Faust James , Malenica Ivana , Herman Richard
Published: June 2021

Sprague‐Dawley (SD) rats exposed to increased dietary fat are an important and relevant animal model simulating consequences of increased adiposity in humans. This model demonstrates mild fasting hyperglycemia, insulin resistance and modulation of postprandial glucose‐stimulated insulin responses and glucose tolerance, the latter implying insufficent islet cell compensation. In this study, two groups of male SD rats fed either chow (5% kcal from fat) or a high‐fat (60% kcal from fat) (HFD) diet for 6 weeks were investigated by determining: (1) post‐prandial insulin, glucose and glucagon concentrations; and (2) islet fractional area comprised of α‐ and β‐cells of isolated pancreata by immunofluorescence. Rats fed a HFD develop significantly increased post‐prandial plasma glucose and insulin concentrations. Preliminary studies suggest substantial disruption of the core:mantle arrangement of islet architecture in the pancreas of HFD rats. Further studies are being conducted to complete these analyses and quantify post‐prandial glucagon concentrations as well as pancreatic insulin and glucagon concentrations. Unquestionably, HFD‐fed rats demonstrated marked functional (‘pre‐diabetic” stage) and structural islet changes which may suggest intrinsic and extrinsic neurohormonal mechanisms of dysfunction.
Acute, NO‐mediated, effects of erythropoietin are not associated with its cardioprotective properties
Authors: Talan Mark I , Ahmet Ismayil , Lakatta Edward G
Published: June 2021

Our serendipitous observation of acute reduction of blood pressure associated with a systemic injection of recombinant human erythropoietin (rhEPO) in the rat prompted a systematic evaluation of the acute effects of rhEPO on cardiovascular function and cardioprotection. Four groups of rats (Wistar, male, 3‐mo old) received bolus i.v. injection of one of the following: physiological saline, rhEPO (3000 U/kg), saline+L‐NAME (15 mg/kg), or rhEPO+L‐NAME. Two hours after injections rats were anesthetized with Isoflurane and subjected to detailed analyses of cardiovascular performance via open chest pressure‐volume loops analyses. In the second experiment four groups of rats were subjected to a permanent ligation of descending coronary artery immediately followed by the same i.v. injections as in the first experiment. Twenty four hours following coronary ligation hearts were harvested and myocardial infarct size (MI) was measured histologically. A significant reduction of arterial blood pressure two hours after a rhEPO injection was accompanied with a reduction of left ventricular systolic function (Table). L‐NAME completely suppressed this acute cardiovascular response to rhEPO. In contrast, the 50% reduction of MI size observed 24 hrs after coronary ligation in rhEPO‐treated vs untreated rats was not affected by L‐NAME treatment. Thus, these novel NO‐mediated acute hemodynamic effects of rhEPO are not associated with EPO‐associated cardioprotection.

Parameters
Saline
rhEPO

ESP
85±5
66±5*

dP/dt+
7136±530
5420±382*

PRSW
51.8±3.9
34.6±2.5*

BPs
90±6
70±3*

BPd
55±5
38±3

BPm
66±6
49±3*

‐p<0.05
A2B Adenosine Receptors Stimulate Release of IL‐6, CXCL1/IL‐8 and Vascular Growth Factor from Cardiac Stromal Cells
Authors: Ryzhov Sergey , Goldstein Anna E , Novitskiy Sergey , Biaggioni Italo , Feoktistov Igor
Published: June 2021

Proangiogenic properties of cardiac stromal cells expressing stem cell antigen (Sca)‐1 were demonstrated in myocardial infarction models. Interstitial adenosine, known to be increased in ischemic tissues, has been suggested to promote angiogenesis. In this study, we tested the hypothesis that stimulation of adenosine receptors on cardiac stromal cells promotes secretion of proangiogenic factors. Using magnetic sorting, we isolated mouse cardiac Sca‐1+CD31− stromal cells. We determined that they predominantly express mRNA encoding the A2B adenosine receptor subtype and low levels of A2A adenosine receptor transcripts. Stimulation of adenosine receptors with 5′‐N‐ethylcarboxamidoadenosine (NECA) increased IL‐6, CXCL1 and vascular growth factor (VEGF) release by 2–4‐fold. Using conditionally immortalized Sca‐1+CD31− stromal cells obtained from wild‐type and A2B receptor knockout mouse hearts, we demonstrated that the A2B receptor subtype is essential for adenosine‐dependent upregulation of their paracrine functions. We found that the human heart also harbors a similar population of stromal cells that predominantly express A2B receptors and respond to stimulation with by increased IL‐6, IL‐8 and VEGF release. Thus, our study identified A2B adenosine receptors on cardiac stromal cells as potential targets for upregulation of proangiogenic factors in the ischemic heart. Support: R01HL095787
TNF‐α induces MMP‐9 expression via a TNFR1/c‐Src/EGFR, PDGFR‐dependent pathway in rat cardiomyoblastic cells
Authors: Hsu Ru-Chun , Yang Chuen-Mao
Published: June 2021

Increased release of tumor necrosis factor alpha (TNF‐α) causes myocardial remodeling and progression of congestive heart failure (CHF). And TNF receptor activates proteolytic system, the matrix metalloproteinases (MMPs), especially MMP‐9, to degrade extracellular components in myocardial remodeling. Therefore, TNF‐α‐inducible matrix metalloproteinase‐9 (MMP‐9) may play a critical role in adverse heart remodeling. However, the molecular mechanisms of TNF‐α‐induced MMP‐9 expression in rat cardiomyoblasts (H9c2) which contributes to cardiac remodeling are largely unknown. Here, we showed that TNF‐α induced MMP‐9 expression and mRNA levels in a time‐dependent manner. This response was attenuated by pretreatment with an anti‐TNFR1 antibody and the inhibitors of MEK1/2 (U0126), JNK1/2 (SP600125), p38 MAPK (SB202190), c‐Src (PP1), EGFR (AG1478), PDGFR (AG1296), PI3K (LY294002), Akt (SH‐5), NADPH oxidase (apocynin and DPI), and NF‐κB (Bay11‐7082). Moreover, TNF‐α‐stimulated ERK1/2 or p38 MAPK phosphorylation and NF‐κB (p65) nuclear translocation were attenuated by pretreatment with AG1478, AG1296, or PP1. Taken together, these results suggest that in H9c2 cells, TNF‐α might activate TNF receptor coupling to transactivate RTK and MAPKs pathways, leading to NF‐κB (p65) nuclear translocation to up‐regulate MMP‐9 expression.
Lipocalin‐2 mediated myocardial extracellular matrix remodeling is correlated with Akt/P38 activity in hearts
Authors: Yang Bo , Vanhoutte Paul M , Wang Yu
Published: June 2021

Lipocalin‐2, a 25‐kDa glycoprotein secreted by adipocytes, belongs to the diversified lipocalin family. Although its physiological functions remain elusive, the expression of this protein is up‐regulated or rapidly induced under various pathological conditions. The impact of lipocalin‐2 on extracellular matrix (ECM) remodeling was determined in cardiac cells of wild type rats. Incubation of primary cultured fibroblasts with recombinant lipocalin‐2 promoted both intracellular collagen expression and extracellular collagen secretion. Up‐regulation of collagen production was also shown in infarcted cardiac tissues after permanent coronary artery ligation in wild type mice, which was positively correlated with enhanced levels of lipocalin‐2 in serum or the infracted heart tissues. The phosphorylation levels of Akt and/or P‐38 were significantly decreased by lipocalin‐2 treatment in primary cultured cardiomyocytes, fibroblasts or infarcted heart tissues. Gelatin zymography analysis of matrix metalloproteinase‐2 (MMP‐2) activity in conditioned medium collected from fibroblasts demonstrated that lipocalin‐2 treatment significantly induced MMP‐2 activity. These results demonstrate that lipocalin‐2 plays a role in mediating myocardial ECM remodeling and that the Akt/P‐38 pathways mediate these effects of the adipokine.
Cross‐talk between α1D‐adrenoceptors and angiotensin II metabolites in vascular smooth muscle is involved in hypertension
Authors: Gallardo-Ortiz Itzell Alejandrina , López-Guerrero Juan Javier , Del Valle-Mondragón Leonardo , Ibarra Maximiliano , López-Sánchez Pedro , Villalobos-Molina Rafael
Published: June 2021

Angiotensin II (Ang II) regulates arterial pressure via RAS, which might contribute to pathogenesis of genetic hypertension. However, local tissue RAS occur in most organs, and other Angs have biological actions: Ang III mimics Ang II; Ang IV acts via AT4R; Ang 1–7 acts via masR. In cardiovascular system α1‐ARs regulate muscle contraction, they are implicated in cardiac malfunction. We explored the in vivo Ang II effect on α1D‐AR function in aorta and tail arteries of Wistar rats. Alzet pumps filled with Ang II (200 ng/kg/min/14 days) were implanted in male Wistar rats; simultaneously, rats were treated with BMY 7378 (10 mg/kg/day/14days) or losartan (1 mg/kg/day/14days). Blood pressure (BP) was measured, and arteries were used for contraction. Ang II increased BP (136 vs 104 mmHg). Losartan prevented hypertension, but BMY 7378 did not. Phenylephrine‐contracted aorta ~40% more in Ang II‐treated rats but not in tail artery. Antagonists blocked Ang II‐produced hypersensitivity in aorta. Plasma Ang III/IV increased ~4.6 fold; Ang 1–7 decreased 33%. Antagonists partially prevented the increase in Ang III/IV, but not in Ang 1–7 which increased. Data support crosstalk between Ang II and α1D‐AR in the vasculature, effect related to Ang II‐induced hypertension and hypersensitivity. Supported by CONACyT 167948 and PAPIIT IN214812, UNAM).
Enhanced Catabolism To Acetaldehyde In Rostral Ventrolateral Medullary Neurons Accounts For The Pressor Effect Of Ethanol In SHRs
Authors: El-Mas Mahmoud M , Abdel-Rahman Abdel A
Published: June 2021

Ethanol microinjection into the rostral ventrolateral medulla (RVLM) elicits sympathoexcitation and hypertension in conscious SHR but not in WKY rats. In this study, evidence was sought to implicate oxidative breakdown of ethanol in this strain‐dependent hypertensive action of ethanol. Biochemical studies revealed higher catalase, and similar aldehyde dehydrogenase (ALDH), activity in RVLM of SHRs, compared with WKY rats. We also investigated the influence of pharmacologic inhibition of catalase (3‐aminotriazole; ATZ) or ALDH (cyanamide) on the cardiovascular effects of intra‐RVLM ethanol or its metabolic product acetaldehyde. Compared with vehicle, ethanol (10 μg/rat) elicited significant increase in blood pressure (BP) in SHRs that lasted for the 60‐min observation period but had no effect on BP in WKY rats. The first oxidation product, acetaldehyde, played a critical role in ethanol‐evoked hypertension because: (i) ATZ virtually abolished ethanol‐evoked pressor response in SHRs; (ii) intra‐RVLM acetaldehyde (2 μg/rat) reproduced the strain‐dependent hypertensive effect of ethanol; (iii) cyanamide uncovered a pressor response to intra‐RVLM acetaldehyde similar to the response observed in SHRs. These findings support the hypothesis that local production of acetaldehyde, due to enhanced catalase activity, in the RVLM mediates the ethanol‐evoked pressor response in the SHR.
Role Of Rostral Ventrolateral Medullary ERK/JNK/p38 MAPK Signaling In The Pressor Effects Of Ethanol And Its Oxidative Product Acetaldehyde In SHRs
Authors: El-Mas Mahmoud M , Fan Ming , Abdel-Rahman Abdel A
Published: June 2021

The mitogen‐activated protein kinases (MAPKs) modulate sympathetic activity within the rostral ventrolateral medulla (RVLM). As intra‐RVLM ethanol causes sympathoexcitation and hypertension in SHRs, we tested the hypotheses: (i) altered MAPKs phosphorylation/dephosphorylation in RVLM underlies ethanol hypertension, and (ii) acetaldehyde, oxidative product of ethanol, replicates molecular and related BP effects of ethanol. The BP effect of either drug was evaluated in presence of inhibitors of JNK (SP600125), ERK1/2 (PD98059), p38 (SB203580), or phosphatase (okadaic acid, OKA). Intra‐RVLM ethanol (10 μg) or acetaldehyde (2 μg) caused similar increases in BP. The pressor action is probably mediated via enhanced ERK1/2 activity because it was (i) paralleled with increased RVLM p‐ERK1/2, and (ii) abolished in PD98059‐treated SHRs. SP600125 abrogated ethanol‐but not acetaldehyde‐evoked hypertension, thus implicating JNK in ethanol effects. Despite increased p‐p38, pharmacological intervention revealed no role for p38 in ethanol hypertension. Although phosphatase activity was not altered by either drug, OKA increased baseline BP and abrogated the pressor effect of ethanol or acetaldehyde. Collectively, enhanced ERK1/2 phosphorylation, without any changes in the dephosphorylation profile, accounts for the pressor effect of ethanol or acetaldehyde in SHRs.
Triton X‐100 inhibits L‐type voltage‐operated calcium channels
Authors: Narang Deepak , Kerr Paul M , Baserman Jason , Tam Raymond , Searle Gavin , Manning-Fox Jocelyn , MacDonald Patrick E , Light Peter E , Holt Andrew , Plane Frances
Published: June 2021

Triton X‐100 (TX‐100) is a non‐ionic detergent widely used for bioassay studies. We have used electrophysiological and functional techniques to examine the effects of TX‐100 on L‐type voltage operated calcium channel (VOCC) activity in vascular smooth muscle cells (VSMCs), cardiac myocytes and pancreatic β‐cells, cell types in which these channels play a critical functional role. TX‐100 (1.6 μM) reversibly inhibited (p<0.01) currents due to expression of recombinant L‐type VOCCs (CaV1.2) reducing peak currents as compared to control. TX‐100 (1.6 μM) also reversibly inhibited (p<0.01) native L‐type VOCC currents from rat VSMCs and cardiac myocytes, and murine and human pancreatic β‐cells reducing peak currents as compared to control. In functional studies, TX‐100 (165 nM‐3.4 μM) caused concentration‐dependent relaxation of rat mesenteric arteries independent of the endothelium. TX‐100 (1.6 μM) also inhibited depolarization‐induced exocytosis in murine and human isolated pancreatic β‐cells. These data indicate that low micromolar concentrations of TX‐100 significantly inhibit L‐type VOCC activity in a number of cell types, an effect paralleled by inhibition of cell functions dependent upon activation of these channels. As this inhibitory effect occurs at concentrations below those used to solubilize proteins and lipophilic agents, it may preclude the use of TX‐100 in some bioassays.
Healing of Saccular Aneurysms Following Platinum Coil Embolization: Lack of Improved Efficacy with Vitamin C Supplementation
Authors: Kadirvel Ramanathan , Ding Yong-Hong , Dai Daying , Lewis Debra , Kallmes David
Published: June 2021

The purpose of the study was to test the hypothesis that systemic administration of vitamin C, through its action of stimulating collagen synthesis and crosslinking, would improve the healing response in experimental aneurysms treated with platinum coil embolization. Nineteen experimental aneurysms in rabbits were embolized with platinum coils (>30% packing density). Animals were divided into three groups. Group 1 (n=6) rabbits served as controls, Group 2 (n=5) rabbits were fed with a vitamin C‐supplemented feed and Group 3 (n=8) rabbits were medicated with vitamin C pills. Subjects were euthanized at 12 weeks following coil implantation and serum vitamin C levels were measured. Digital subtraction angiography was used to evaluate stability after embolization. Histological samples were examined with a grading system (range, 0–12) based on the neck and dome features. Masson Trichrome was employed to evaluate the collagen deposition. One‐way analysis of variance was used to test the significance in histological healing and angiographic measurements between groups. There were no significant differences between groups in aneurysm size or angiographic findings. Mean serum vitamin C concentration was significantly higher in Group 3 (45.4±9.0 mM) and Group 2 (38.6±8.9 mM) compared to Group 1 (21.1±3.6 mM). There was no statistically significant change in the level of vitamin C between Group 2 and Group 3. There was no significant difference in histological scores or collagen deposition among groups. Our results suggest that vitamin C supplementation following platinum coil embolization may not improve long‐term cerebral aneurysm. This study was supported by the American Heart Association (09SDG2160146‐01).
Ethanol Attenuation of Peripheral NMDAR‐mediated Pressor Response
Authors: McGee Marie , Abdel-Rahman Abdel
Published: June 2021

With clear dependence of ethanol actions on central NMDAR signaling, studies on the unexplored interaction between ethanol and peripheral cardiovascular NMDAR are warranted. We tested the hypothesis that peripheral vascular effects of ethanol might involve blockade of peripheral NMDAR; activation of the latter causes increases in blood pressure (BP), vascular ROS and NOS‐derived NO generation. Hemodynamic studies were conducted in seven groups (n=5–6) of conscious Sprague Dawley male rats that received: 1) Saline, 2) NMDA (125–1000 μg/kg), 3) Ethanol (1g/kg), 4) Ethanol + NMDA, 5) Saline infusion, 6) NMDA (180 μg/kg/min for 30 min) or 7) Ethanol + NMDA infusion. Ethanol or its vehicle (water) was administered by gavage 30 min prior to either bolus i.v. injections or infusion of NMDA or its vehicle. Ethanol, which had no effect on BP, caused a downward shift in the NMDA dose‐pressor response curve. It was important to evaluate the interaction between ethanol and sustained peripheral NMDAR activation (groups 5–7) because bolus NMDA elicited short lived (approx.1 min) response. Ethanol attenuated the sustained NMDA pressor response during the entire 30 min of NMDA infusion. Further, ethanol abrogated the peripheral NMDAR‐mediated increases in vascular NO and ROS generation. These findings provide new insight into a potential role for peripheral NMDAR in the cardiovascular effects of ethanol [NIH grant AA07839].
Genitourinary dysfunctions associated with heart failure in model of chronic volume overload in rats
Authors: Claudino Mario Angelo , Silva Fabio Henrique , Rojas-Moscoso Julio , Priviero Fernanda , Antunes Edson , De Nucci Gilberto
Published: June 2021

Chronic heart failure (CHF) patients showed that 85% have reported some episode of erectile dysfunction (ED) and 34% reported lower urinary tract symptoms (LUTS). We evaluate the relaxant‐ and contractile‐mechanisms of isolated corpus cavernosum (CC) and detrusor smooth muscle (DSM) of CHF rats (CHFR). Concentration‐responses curves to phenilephrine (PE) in CC; and carbachol (CCh), KCl in DSM were obtained from CHF rats (12wks). Nitrergic and neurogenic responses induced by electrical‐field stimulation were obtained in CC and DSM, respectively. PE contracted CC with a potency (pEC50) of 5.44±0.04. The pEC50 of PE did not change in CHFR (5.36±0.06), but, the maximal response (Emax) was increased (2.5±0.1mN/mg; P<0.05) compared with sham rats (SR; 1.9±0.1mN/mg). Nitrergic relaxation in CC was significantly decreased at higher frequencies vs SR. CCh and KCl contracted DSM with a pEC50 of 5.42±0.07 and 0.90±0.12, respectively. The pEC50 of CCh and KCl did not change in CHF‐R (5.68±0.07; 1.34±0.11, respect.), but, the Emax were increased (1.09±0.07; 0.88±0.05mN/mg, respect; P<0.05) compared with SR (1.45±0.10; 1.29±0.11 mN/mg, respect.). Neurogenic contractions in DSM were significantly increased in all frequencies vs SR. In conclusion, CHFR exhibit an impaired nitrergic response in CC and an increase of contractile mechanism in DSM that may contribute to genitourinary dysfunctions in CHF. FAPESP/CNPq.
Reactivity changes in coronary artery and thoracic aorta in the gene mutant mice sgcd (B6.129 Sgcdtm1Mcn)
Authors: Marin-Romero Maria Carmen , Guevara-Balcazar Gustavo , Rosas Haydee , Coral-Vazquez Ramon Mauricio , Bobadilla-Lugo Rosa Amalia , Castillo-Hernandez Maria Carmen
Published: June 2021

Objective

Study of cardiovascular reactivity changes in the gene mutant mice sgcd.

Introduction

Deletion of d‐sarcoglicano gene (delta‐SG) is related with structural and functional changes of squeletical, smooth and cardiac muscle which are related with limb‐girdle muscular dystrophy and cardiomiopathy. In this work we study the effect of some contractile and vasodilator agonist like angiotensin II and acethylcholine in this experimental model of dystrophy.

Methods

We used wild‐type and Knock‐out 5 months old female mice. We obtain thoracic aorta and the heart and both were immediately excised and placed in cold buffer, cleaned and freed from surrounding connective tissue. Isolated aortic rings and Langendorff system were maintained at 37° C, pH 7.4, were and bubbled with a mixture of 95% O2 and 5% CO2. After that we probe angiotnesin II (10−9 a 10−6M) with and without L‐NAME( sNOS antagonist) and indomethacin (COX‐1 and COX‐2 antagonist ).

Results and conclusions

We obtein significant differences between wild type and knock‐out mice, in the knock‐out mice we found an increase in the response of angiotensin II for that reason we suggest the participation of one contractile prostanoid in this effect. For that reason we decide to inhibit the contractile effect of angiotensin II with indometacin and the result was the inhibition of the contractile response. In other hand we analyse the vasodilator effect of acethylcholine at different concentrations and the result was less vasodilator effect in knock‐out mice, however we did not have differences in the vasodilator effect of nitroprusiate between wild type and knock‐out.
A Novel Antithrombotic Agent Targeting the Human Thromboxane A2 Receptor
Authors: Murad John P , Espinosa Enma Veronica Paez , Ting Harold J , McClure Diane , Khasawneh Fadi T
Published: June 2021

In efforts to define new targets for antithrombotic purposes, there is interest in utilizing antibodies targeting ligand binding domains of platelet receptors. To this end, we have recently shown that an antibody (designated C‐EL2Ab), which targets the C‐terminus of the second extracellular loop (C‐EL2) of the thromboxane A2 receptor (TPR), selectively blocks TPR‐mediated platelet aggregation. This inhibitory effect was evident under both in vitro and ex vivo experimental conditions. Our current studies employed an in vivo model of thrombosis to determine the potential for the use of C‐EL2Ab as a thromboprotective agent. Thus, a ferric chloride carotid artery injury thrombosis model revealed a significant increase in time for occlusion in mice treated with C‐EL2Ab, when compared to controls such as normal rabbit IgG, or an antibody which targets a region separate from the ligand binding site (i.e., EL1). We next examined the effect of C‐EL2Ab on hemostasis. Bleeding time results showed no increase in tail bleeding times in C‐EL2Ab treated mice, compared to controls. Collectively, these results clearly demonstrate that C‐EL2Ab has anti‐platelet/anti‐thrombotic effects, and is devoid of increased bleeding risk. Moreover, the identification of a functionally active TPR sequence will significantly aid molecular modeling study predictions for organic derivatives which possess in vivo activity.
Antioxidants N‐Acetylcysteine and Allopurinol attenuation of postischemic myocardial injury in diabetic rats involve Akt and STAT3 mediated eNOS activation
Authors: Wang Tingting , Mao Xiaowen , Qiao Shigang , Lei Shaoqing , Ng Kwok F.J. , Irwin Michael G. , Xia Zhengyuan
Published: June 2021

Hyperglycemia‐induced oxidative stress exacerbates myocardial ischemic reperfusion (MI/R) injury. N‐acetylcysteine (NAC) and allopurinol (ALP) reduced MI/R injury in streptozotocin (STZ)‐induced diabetes (PLoS One. 2011;6:e23967), but the mechanism is unclear. We postulated that NAC and ALP attenuate MI/R injury via PI3k/Akt and Jak2/STAT3 mediated eNOS activation in diabetes. Control (C) or STZ‐induced diabetic (D) rats were untreated or treated with NAC (1.5g/kg/day) or ALP (100 mg/kg/day) or their combination for four weeks starting one week after STZ injection. NAC and ALP synergistically decreased myocardial infarct size in D rats subjected to 30 minutes of coronary artery occlusion and 2 hours reperfusion, and restored phosphorylations of cardiac Akt, STAT3 and eNOS (P<0.05 NAC+ALP vs. D). Exposure of rat cardiomyocytes to high glucose and 45 min hypoxia and 2 hours reoxygenation induced post‐hypoxic cell death reflected as increase of lactate dehydrogenase leakage and reduced cell viability. NAC and ALP synergistically reduced post‐hypoxic cell death and enhanced phosphorylations of Akt, STAT3 and eNOS. The PI3K inhibitor wortmannin and Jak2 inhibitor AG490, respectively attenuated NAC and ALP's protective effects in vivo and in vitro. We conclude that activation of both the PI3K/Akt and the Jak2/STAT3 signaling are involved in NAC and ALP mediated attenuation of MI/R injury in diabetes.