bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of chronic ibuprofen treatment on ventilatory acclimatization to hypoxia
Authors: Popa Daniel , Fu Zhenxing , Powell Frank
Published: June 2021

Inflammatory processes have been shown recently to increase O2‐sensitivity of the carotid body during chronic sustained hypoxia, CH (Am J Physiol Lung Cell Mol Physiol 296: L158–166, 2009). We hypothesized that blocking inflammation with an NSAID (ibuprofen 4mg/kg daily IP) would block ventilatory acclimatization to hypoxia, VAH (CH = 10% O2, 7–11 days). To test this, we studied the hypoxic ventilatory response in 4 groups of adult male rats with barometric pressure plethysmography: CNS = chronic normoxia injected with saline (controls); CNI = chronic normoxia with ibuprofen; CHS = CH with saline; CHI = CH with ibuprofen. Data in the tables below (mean ± SEM) show that ibuprofen blocks the increase in ventilation with CH, primarily by an effect on fR. Values bolded and with an asterisk show significant (p< 0.01) increases relative to CNS rats (VI) and CHI rats (fR).

VI (mL/(min kg))

Group
21% O2
10% O2

CNS (n=7)
641 ± 28
1122 ± 92

CNI (n=7)
685 ± 43
1015 ± 67

CHS (n=6)
1070 ± 103*
1588 ± 144*

CHI (n=7)
978 ± 63*
1108 ± 116

fR (breaths/min)

Group
21% O2
10% O2

CNS (n=7)
123 ± 12
179 ± 14

CNI (n=7)
143 ± 10
180 ± 9

CHS (n=6)
149 ± 6*
206 ± 7*

CHI (n=7)
136 ± 4
162 ± 6

Further study is necessary to determine if inflammatory signals for VAH occur at other points in the ventilatory chemoreflex arc also. Supported by RO1 NIH‐HL‐081823.
Activation of adenosine A2A receptor on GABAergic inputs to 2nd‐order neurons of peripheral chemoreceptors in the NTS
Authors: Zhang Weirong , Mifflin Steve
Published: June 2021

Hypoxia elevates extracellular adenosine level in the NTS. Both adenosine A1 and A2A receptors exist in the NTS. Unlike inhibitory A1 receptor, activation of adenosine A2A receptor usually has a facilitation effect on neural function. In this project, we studied the effect of A2A receptor activation on GABAergic inputs to second‐order NTS neurons. Whole‐cell recordings were performed in NTS neurons in brainstem slices. Second‐order neurons were identified following DiA labeling of carotid bodies. Recordings were performed with CNQX but no TTX to study action potential‐dependent spontaneous pre‐synaptic GABA release (sIPSCs). In 3/7 NTS neurons, application of A2A receptor agonist CGS 21680 at 100 nM induced a significant increase in the frequency of sIPSCs (155±12% of control, p<0.05) without a significant change of the amplitude (95±3% of control, p>0.05). In the other 4/7 NTS neurons, CGS 21680 did not induce a significant change in sIPSCs frequency (93±4% of control, p>0.05). In 3 of these 4 neurons, CGS 21680 induced a significant decrease in sIPSCs amplitude (86±2% of control, p<0.05). The results indicate a heterogeneous and complex function of adenosine A2A receptor in the NTS. The lack of response in some neurons may be due to a lack of receptor on certain GABAergic neurons or indirect mechanisms involving other neurochemicals and ion channels. This work is supported by AHA BGIA 0865269F and NIH HL88052.
Heavy metals zinc, cadmium and copper stimulate pulmonary C‐fibers via direct activation of TRPA1
Authors: Gu Qihai , Lin Ruei‐Lung
Published: June 2021

Airway exposure to zinc dust and zinc‐containing ambient particulates can cause symptoms of airway irritation and inflammation. However, the underlying molecular and cellular mechanisms are largely unknown. Transient receptor potential A1 (TRPA1) is selectively expressed in a subpopulation of pulmonary C‐fiber afferents, and has been considered as a major irritant sensor in the lung and airways. Using whole‐cell patch‐clamp recording and Ca2+ imaging, we have demonstrated that application of ZnCl2 concentration‐dependently evoked inward current and Ca2+ transient in isolated vagal pulmonary sensory neurons; both responses were almost completely prevented after pretreatment with AP18, a selective TRPA1 antagonist. In anesthetized spontaneously breathing animals, intratracheal instillation of ZnCl2 (2 mM, 25 μl) evoked pronounced respiratory sensory irritation in wild‐type mice, and the effect was essentially absent in TRPA1‐deficient mice. In addition, our study showed that two other heavy metals cadmium and copper also stimulated pulmonary sensory neurons via direct activation of TRPA1. In summary, our results suggest that activation of TRPA1 in pulmonary C‐fiber sensory nerves may contribute to the respiratory toxicity induced by airway exposure to these three heavy metals. Funded in part by grants from NIH AI076714 and AHA 0835320N.
miRNA Profiles of Spontaneous Canine Lymphoid Tumors
Authors: Uhl Elizabeth W , Krimer Paula , Tompkins S.Mark , Lester Chantel , Suter Steven E
Published: June 2021

Lymphoma is among the most common tumors of the dog, accounting for about 25% of all cancers. miRNAs are highly conserved across species, however their role in the pathogenesis of canine neoplasia is unknown. The purpose of this study was to begin generating miRNA profiles of spontaneous canine B and T cell tumors using cancer microRNA qPCR arrays developed for use in human samples. Over 90% of human miRNA probes detected canine miRNAs. Six peripheral blood mononuclear cell (PBMC), 7 T cell tumor and 17 B cell tumor samples were analyzed, and various miRNAs were investigated to determine the most consistent and precise internal controls. Some samples were run repeatedly to determine coefficients of variation. At least 20% of miRNAs were upregulated in tumors relative to PBMC. Nineteen were increased and 1 decreased in T cell tumors, 9 were increased in B cell tumors, and 8 were upregulated in both B and T cell tumors. In addition, the magnitude of miRNA upregulation was generally greater in T cells than B cell tumors. The results indicate miRNA profiles have potential predictive, diagnostic and prognostic potential in canine lymphoma.
Patterns of Coronary Atherosclerosis in a Hypercholesterolemic Swine Model
Authors: Arce‐Esquivel Arturo A. , Turk James R. , Laughlin M. Harold
Published: June 2021

Inflammation and endothelial activation are the initial histological changes within the arterial wall that eventually lead to the development of advanced lesions of atherosclerosis. Atherosclerosis progresses at different rates among the arterial segments, especially in the coronary arteries. This study was designed primarily to characterize the anatomical patterns of atherosclerotic disease in the coronary arteries of hereditary hypercholesterolemic (HH) swine. We also tested the hypothesis that exercise training (ExT) would decrease the progression of initial changes in atherosclerotic lesions of HH swine. Fifteen HH pigs were randomly assigned into either exercise trained (EX) or sedentary groups (SED). Exercise training consisted of a 16 week progressive treadmill training program. At sacrifice left anterior descending (LAD) and right coronary artery (RCA) were harvested. Immunohistochemistry was used to quantify the presence of MCP‐1, VCAM‐1, iNOS and CD‐44 antibodies. The average percentage for MCP‐1, VCAM‐1, iNOS and CD‐44 staining tended to be greater in the LADs. ExT did not significantly reduce the prevalence of changes. We conclude that the patterns of coronary atherosclerosis in swine are similar to those in humans, and ExT does not significantly reduce the progression of initial morphologic changes in coronary arteries in this model of disease.

Supported by NIH HL52940.
Tumor Necrosis Factor‐alpha Mediated Changes in Cardiomyocyte Adhesion
Authors: Brower Gregory L. , Du Yan , Plante Eric , Hill Benjamin C. , Janicki Joseph S.
Published: June 2021

We have established that myocardial levels of tumor necrosis factor‐a (TNF) are acutely elevated in the aortocaval fistula model of heart failure. Furthermore, the elevations in TNF coincide with the initial development of ventricular dilatation induced by the sustained volume overload. It was our hypothesis that TNF induced alterations in integrin mediated cardiomyocyte adhesion contribute to this adverse myocardial remodeling. To test this supposition, left ventricular cardiomyocytes were isolated from normal adult hearts (n = 6) by perfusion with collagenase. Aliquots of 5×104 calcium tolerant isolated cardiomyocytes were incubated for 0.5 hr in DMEN media containing TNF (50 ng/ml), TNF + PP2 (Src kinase inhibitor), TNF + SB203580 (p38 MAP kinase inhibitor), or media alone. The cardiomyocytes were then plated on laminin coated wells for 2 hr, after which the wells were washed and the percentage of adherent cells determined. Incubation with TNF produced a significant 45% reduction in cardiomyocyte adhesion to laminin. This decrease was markedly attenuated by the Src kinase inhibitor PP2, whereas the p38 MAP kinase inhibitor did not prevent the TNF mediated decrease in adhesion. This study implicates reductions in integrin mediated cardiomyocyte adhesion induced by TNF signaling via Src kinase dependent pathways in the adverse myocardial contributing to alterations in ventricular structure and function.
Abacavir (ABC) Has No Cardiac Mitochondrial Toxicity in Multiple Trangenic Murine Models Compared to Zidovudine (AZT)
Authors: Kohler James J , Hosseini Seyed H. , Koczor Christopher A. , Fields Earl , Green Elgin , Abuin Allison , Ludaway Tomika , Russ Rodney , Zhao Peter , Lewis William
Published: June 2021

ABC and AZT are both nucleoside reverse transcriptase inhibitors (NRTIs) central to effective antiretroviral therapy for HIV/AIDS. Despite therapeutic success, toxicities associated with NRTI‐induced mitochondrial dysfunction have been reported. Genetically engineered mice with knock‐out (KO) or overexpression (OX) of mitochondrial superoxide dismutase (SOD2+/− KO and SOD2‐OX, respectively), mitochondrially targeted catalase (mCAT‐TG), aldehyde dehydrogenase 2 (ALDH2 KO), alcohol dehydrogenase (ADH‐TG), or wild‐type littermates (C57/BL6, WT) were treated with AZT (0.22 mg/d) or ABC (3.125 mg/d) for 35 days. Mitochondrial DNA (mtDNA) abundance and left‐ventricle (LV) mass and LV end‐diastolic dimension were determined. AZT induced cardiac oxidative stress and LV dysfunction in WTs. Effects worsened in KOs while OX and TGs prevented or attenuated AZT‐induced cardiac oxidative stress. Conversely, ABC had no effect on any cohorts, including WTs, suggesting no associated cardiac oxidative stress with ABC. These data support the clinical use of ABC as replacement for AZT in preventing cardiac oxidative stress.
Sequence analysis of type VI collagen subunits in cardiomyopathic hamster hearts
Authors: Suzuki Osamu , Koura Minako , Noguchi Yoko , Uchio‐Yamada Kozue , Matsuda Junichiro
Published: June 2021

At the AALAS 2009 meeting, we reported an accumulation of collagen type VI (COL6) in the hearts of cardiomyopathic hamsters (J2N‐k) in comparison with normal controls (J2N‐n). In this study, we determined the cDNA sequences of three subunits of COL6 in the cardiomyopathic hearts of J2N‐k hamsters using a SMARTer RACE cDNA amplification kit (Clontech) with total RNA extracted from a 6‐month‐old J2N‐k male hamster heart and subsequent direct sequencing of the PCR products. Primers were designed from the corresponding mouse and rat sequences. The sequences have been deposited in DDBJ with the accession numbers AB529512, AB529513, and AB530134 for COL6A1, COL6A2, and COL6A3, respectively. NCBI conserved domain searches indicated that all three subunits contained the same vWFA domain structures as their mouse counterparts. In particular, hamster heart COL6A3 lacks three domains in the N‐terminus, as in normal mouse and human hearts. These results suggest that the accumulation of COL6 in J2N‐k hearts is caused by altered expression and/or degradation of COL6, not by its structural abnormality. This work was supported by a grant from the Ministry of Health, Labor, and Welfare of Japan.
EFFECT OF EPICATECHIN AND NALOXONE ON CARDIO‐PROTECTIVE PHENOTYPE
Authors: Panneerselvam Mathivadhani , Kawaraguchi Yoshitaka , Horikawa Yousuke T , Saldana Michelle , Patel Piyush M , Roth David M , Patel Hemal H.
Published: June 2021

Epicatechin is a well know antioxidant linked with varieties of protective effects in both humans and animals. However, a receptor mediated effect has not been proposed. We tested the hypothesis that epicatechin mediates cardioprotection via opioid receptor activation. Mice were randomly assigned to the following four groups: control, epicatechin, naloxone, and epicatechin+naloxone. Epicatechin was administered by oral gavage daily (1mg/kg) for 10 days. Naloxone was administered by intraperitioneal injection daily (5mg/kg) for 10 days. Whole heart homogenates were assayed for the opioid downstream targets. Epicatechin induced a protective phenotype in mice by increasing the p‐SRC, p‐AKT, p‐ IkBa, and by decreasing JNK, and CAD expression. Naloxone administration withdrew the protective effect of epicatechin. Epicatechin‐induced protective phenotype was blocked by naloxone. Blocking the opioid receptor with naloxone abolished the protective phenotype and cardioprotective effect provided by epicatechin. These data suggest that epicatechin acts via opioid receptor.
Multiple dosings wtih acidic retinoids increase retinol stores and expression of retinoid homeostatic genes in the lung of neonatal rats
Authors: Wu Lili , Ross A. Catharine
Published: June 2021

Previously we have shown that vitamin A (VA) combined with acidic retinoids synergistically increases retinol uptake and retinyl ester (RE) formation in neonatal rat lung, concomitant with the expression of several retinoid homeostatic genes: LRAT (lecithin:retinol acyltransferase), CYP26B1 (a cytochrome P450), and Stra6 (stimulated by retinoic acid gene 6). In the present study we compared the response to VA alone or combined with retinoic acid (RA) or a analog, Am580, in two timing protocols: single early dosing (d 4) vs. multiple dosings throughout the period of lung septation (d 4, 7, 11, 14). Multiple dosing resulted in a higher, cumulative increase in lung RE content for all treatments: vehicle<RA≅VA<Am580<VARA<VAAm580. However, most of the retinoid homeostatic genes were up‐regulated by acidic retinoids to the same extent after a single vs. multiple dosings. Lung functional gene, surfactant protein‐A (SPA1) mRNA remained nearly constant with both treatment and timing. In conclusion, multiple treatments of VA and acidic retinoids in combination during the septation period greatly increased neonatal lung RE content in a synergistic and cumulative manner. Repeated but transient induction of retinoid homeostatic genes by acidic retinoids at the time of each dosing may explain the observed cumulative synergistic enhancement of RE formation.

Support: NIH CA90214.

Grant Funding Source: NIH CA90214
Mice deficient in alpha(1,3)‐fucosyltransferase‐IV and ‐VII are resistant to exogenous insulin
Authors: Mackey Lantz C , Morales‐Levy Maria , Homeister Jonathon W.
Published: June 2021

Fucosylation of selectin ligands by alpha(1,3)‐fucosyltransferases (FucT)‐IV or ‐VII is required for sialyl Lewis x formation and selectin‐binding activity. FucT‐IV(−/−)/FucT‐VII(−/−) mice (DKO) have severe defects in leukocyte trafficking to sites of inflammation and lymphocyte homing to lymphoid organs, altering their inflammatory response. Inflammation is associated with insulin resistance. Insulin function and glucose metabolism were determined in wild‐type (WT), FucT‐IV(−/−), FucT‐VII(−/−), and DKO mice (n ≥ 9, 7, 8, and 9 per group, respectively). Baseline blood glucose concentrations were not different between groups. Insulin (0.5 unit/kg i.p.) sensitivity tests showed decreased clearance of blood glucose in FucT‐IV(−/−), FucT‐VII(−/−), and DKO mice starting at 15 to 30 minutes after administration. In contrast, the elevation and clearance of blood glucose was not different (15 to 120 min) between WT, FucT‐IV(−/−), FucT‐VII(−/−), or DKO mice in glucose tolerance tests (2 mg/g, oral gavage). Plasma insulin concentrations (by ELISA) at 0, 15, or 30 minutes of the glucose tolerance test were not different between WT, FucT‐IV(−/−), FucT‐VII(−/−), or DKO mice. These data show that DKO mice are resistant to exogenous insulin challenge likely due to an altered inflammatory state, but otherwise maintain normal blood glucose metabolic responses. Support by AHA FTF Award 0275023N and RO1‐HL090823.
Whole Slide Imaging System: a Valuable Tool for Biorepositories
Authors: Handorf Charles R , Johns Cameila , Zhang Jie , Kulkarni Anand L
Published: June 2021

Tissue biorepositories classically exist to support biomedical research and development by collecting, classifying, preserving, and supplying biological material. The advent of whole slide imaging (WSI) systems provides a new way to approach the information inherent in tissues. Archiving of static digital images from microscopic slides is of limited value for research, whereas digitizing all of the information on a slide opens up new avenues for collaboration and quantification of the information contained in a slide. We have evaluated 20 tissue cases representing a variety of tissue types and pathological conditions; data collected include evaluation of diagnostic suitability by a panel of pathologists, scanning quality at 20X and 40X magnification, total processing time, scanning time, and file size. Operational characteristics for WSI systems must be optimized; however, these systems will be a valuable tool for biorepositories to create digital archives, to establish the quality of tissues requested by researchers, and to augment data sharing.

NCRR 1S10RR025665‐01
Evaluation of the initial host immune response to Mycobacterium avium subspecies paratuberculosis infection in exposed and naive calves using matrix bipolymers
Authors: Plattner Brandon Lee , Huffman Elise , Hostetter Jesse M
Published: June 2021

We have developed a model to explore the early immune response to Mycobacterium avium subspecies paratuberculosis (Map) in the calf using a gel matrix biopolymer. This system utilized subcutaneous placement of a liquid polymer containing live Map that rapidly polymerizes and retains recruited cellular infiltrates and soluble mediators. After 48 hours the matrix is removed and cellular infiltrates and cytokines are measured by immunofluorescence, multi‐parameter flow cytometry and Luminex ELISA assays. A focus of this study was to evaluate recruitment of gamma‐delta T (gdT) cell subsets to the mycobacterial infection site and determine how these cells influence the development of the adaptive immune response. Our results show distinct cellular and cytokine profiles in the gels recovered from animals that are naïve vs previously sensitized to Map antigen. In addition, our data supports our hypothesis that bovine gdT cell subsets are differentially recruited to early mycobacterial infection sites with respect to prior exposure to Map antigens. We also found that different bovine gdT cell subsets display distinct patterns of cytokine secretion. Our results provide unique insight into initial host responses at mycobacterial infection sites that may promote novel diagnostic strategies. This work was supported by the Iowa Veterinary Medical Association and the Iowa Healthy Livestock Initiative.
Quantification of von Willebrand Factor and von Willebrand Factor Propeptide in Patients with End Stage Renal Disease
Authors: Davis Rachael , Bansal Vinod , Litinas Evangelos , Rahman Saudur , Hoppensteadt Debra , Conway Brooke , Fareed Jawed
Published: June 2021

In End Stage Renal Disease (ESRD), systemic vascular changes contribute to thrombotic comorbidities. The purpose of this study was to characterize the role of vWF in these inflammatory changes. Plasma samples from 51 patients with clinically confirmed (ESRD) were collected prior to maintenance hemodialysis. A group of 50 normal individuals, both male and female, was included as control. Concentrations of von Willebrand Factor (vWF) and von Willebrand Factor Propeptide (vWFpp) were quantified using the GTI® vWF & Propeptide Assay. Compared to controls, the levels of vWF and vWFpp were increased in patients with ESRD. These patients showed a 1.3 fold increase in vWF (mean 128 ± 69 U/dL, range 9.2 to 308) compared to control (mean 100 ± 60, range 22 to 332). Similarly, there was a 1.6 fold increase in vWFpp (mean 148 ± 92 U/dL, range 8.0 to 361) compared to control (mean 92 ± 23, range 60 to 163). However, the ratio of vWFpp:vWF (mean 1.2 ± 0.6, range 0.4 to 3.3) was unchanged compared to control. This study shows a previously uncharacterized increase in vWFpp and validates the up‐regulation of vWF in ESRD. The normal vWFpp:vWF ratio implies an increased production in vWF in response to endothelial damage without any apparent down‐regulation of ADAMTS‐13 mediated degredation of vWF. Further studies are required to assess the role of ADAMTS‐13 in ESRD to better understand the interplay of all these components.
TLR 9 and TLR 2 Play Critical Role in Recognition of MRSA and MSSA in Mesenchymal Stem Cells
Authors: Maiti Aparna , Jiranek William A
Published: June 2021

Toll like receptors (TLRs) have been implicated by their ability to recognize and more significantly discriminate between different classes of pathogens. Having the central role in recognition of microbes, type of TLR expressed in the cell is important to understand the pathogenicity. Human bone marrow derived mesenchymal stem cells (MSC) are multipotent progenitors that also possess regulatory properties. We characterize the interactions of MSCs with Staphylococcus species, the most important pathogens in the body. In this study we analyzed TLR1‐9 expression by using RT‐PCR in bone marrow derived MSC. Our data revealed that normal MSCs express high level of TLR1, TLR3 and TLR4 and very low levels of TLR5 and TLR6 but do not normally express TLR7, TLR8, TLR9, and TLR10. Further, we observed that TLR9 was highly expressed and critical for recognition of methicillin resistant Staphylococcus aureus (MRSA) with no expression of TLR1 and TLR3. While TLR2 and TLR4 were weakly expressed. In contrast, we observed high expression of TLR2 in response to methicillin susceptible Staphylococcus aereus (MSSA) along with moderate expression TLR1, TLR3.
A role for βENaC protein in microvessel formation
Authors: Adair Thomas H. , Drummond Heather A.
Published: June 2021

Previous studies demonstrate that β Epithelial Na+ Channel (βENaC) is required for vascular smooth muscle cell migration, an essential step in angiogenesis. However, the importance of βENaC in angiogenesis is unknown. We tested the hypothesis that VEGF can stimulate angiogenesis by upregulating βENaC expression using the rat aortic ring angiogenesis model. Cultures were treated with VEGF (50 ng/ml) and the ENaC inhibitor benzamil (0.1, 1 and 10 μM) over 6–8 days. The lowest dose of benzamil inhibited 44% of new microvessels formed in VEGF treated cultures, whereas 1 and 10 μM benzamil abolished VEGF induced growth. To determine if VEGF stimulates expression of βENaC protein, we evaluated the effect of VEGF on βENaC expression using Western blotting in a pooled sample of aortic rings and semi‐quantitative immunolabeling of newly formed microvessels. We found that VEGF increased βENaC expression in proportion to vessel outgrowth (~2 fold). To determine if VEGF mediated angiogenesis requires βENaC protein, we evaluated aortic ring microvessel formation in a mouse model of reduced βENaC. We found that microvessel formation was inhibited >50% at day 8. The results indicate that 1) VEGF stimulates βENaC expression and 2) VEGF mediated angiogenesis in the aortic ring model requires normal βENaC expression. (HL‐51971, HL‐086996).
Sympathetic Nerves and Endothelium Influence the Vasoconstrictor Effect of Low Concentrations of Ouabain in Pressurized Small Arteries
Authors: Raina Hema , Zhang Qingli , Rhee Albert , Pallone Thomas L , Wier Withrow Gil
Published: June 2021

Here, we tested the involvement of arterial endothelium and peri‐vascular sympathetic nerve terminals (NT) in ouabain‐induced vasoconstriction. Segments of rat arteries were pressurized and exposed to ouabain (10−11M–10−7M). Endothelium removal enhanced ouabain‐induced (10−9M) vasoconstriction as much as 2‐fold. A component of the ouabain‐induced vasoconstriction is due to enhanced spontaneous release of norepinephrine (NE) from NT's in the arterial wall. The α1‐adrenoceptor blocker, prazosin (10−6M) decreased ouabain induced vasoconstrictions by as much as 50%. The electrically evoked release of NE from sympathetic NT was not affected by ouabain (< 10−7M). However, neither the ouabain induced contraction nor the NE release (measured directly by carbon fiber amperometry) was increased by sympathetic nerve activity (SNA). However, following brief bursts of SNA, vasoconstrictor responses to ouabain were transiently increased (1.75‐fold). In arteries lacking endothelium and exposed to prazosin, ouabain (>10−11M) caused vasoconstriction, indicating a direct effect on arterial smooth muscle. Conclusions: Endothelium opposes ouabain induced vasoconstriction, which is caused by both enhanced spontaneous NE release and direct effects on smooth muscle. Ouabain does not enhance SNA mediated contractions, but SNA enhances ouabain‐induced contraction.

NIH grants R01‐HL073094 & P01‐HL078870
Comparison of the pharmacological and sequence methods for assessing baroreflex control blood pressure via heart rate and renal sympathetic nerve activity
Authors: Guild Sarah‐Jane , Soo Camelia Ling Ling , Head Geoffery A , Malpas Simon C , Barrett Carolyn J
Published: June 2021

In many cardiovascular diseases, the sensitivity of the baroreflex is impaired. To determine baroreflex sensitivity in the laboratory, we have traditionally infused vasoactive drugs to alter blood pressure and recorded the responses of renal sympathetic nerve activity and heart rate. However, the pharmacological method is not always practical and thus there is a shift to obtaining baroreflex response curves from naturally occurring fluctuations in arterial pressure. The aim of this project was to establish the practicalities of using spontaneous fluctuations in arterial pressure to determine the sensitivity of the baroreflex in conscious unrestrained animals and make comparisons to traditional pharmacological methods. Gains of the baroreflex control of heart rate were comparable between the two methods but spontaneous baroreflex gains for the baroreflex control for sympathetic nerve activity were greater than those obtained from pharmacological methods. It must also be noted that the sequence methods only provides gain measurements and no information on the operating range of the reflex. Supported by the Health Research Council of New Zealand and University of Auckland Research Committee.
The role of TRPV4 in rat parenchymal arterioles
Authors: Baylie Rachael Louise , Tavares Matthew , Navedo Manuel , Santana Luis F. , Brayden Joseph
Published: June 2021

Small arteries within the cerebral cortex, i.e. the parenchymal arterioles (PAs), have unique properties and play important roles in neurovascular coupling and functional hyperemia. In the present study, the role of the Transient Receptor Potential channel, TRPV4 in PA smooth muscle was investigated. PA smooth muscle cells stained positive for TRPV4 and exhibited TRPV4‐like whole cell currents, being augmented by temperature (21–30 °C) at Vh = −60 mV and by 4αPDD (5 μM) during voltage ramps (−120 mV to +80mV). In PAs with myogenic tone, inhibition of TRPV4 with HC‐067047 (1 μM) caused dilation, whilst TRPV4 activation with 4αPDD (5 μM) and GSK1016790A (100 nM) led to constriction. 4αPDD increased myocyte Ca2+in isolated PAs. Using Total Internal Reflection Fluorescence (TIRF) microscopy, discrete Ca2+ influx events that did not involve CaV1.2 channels or Ca2+ release from intracellular stores, were observed in isolated PA myocytes. Activators of TRPV4, GSK1016790A and 11,12 epoxyeicosatrienoic acid (300 nM), increased the nPs (n=number of quanta, Ps= probability of occurrence) and density of influx events, which were subsequently termed TRPV4‐sparklets. TRPV4‐sparklets had a quantal level of ~100 nM Ca2+. These data suggest that TRPV4 contributes to Ca2+ influx and constriction of PAs.
Subarachnoid hemorrhage‐induced cerebral vasospasm stimulates mobilization of circulating progenitor cells
Authors: Santhanam Anantha Vijay R , Smith Leslie A , Katusic Zvonimir S
Published: June 2021

Mobilization of hematopoietic progenitor cells is predictive of functional recovery in stroke. In the present study, alterations in progenitor cell counts were studied in an experimental model of subarachnoid hemorrhage (SAH)‐induced cerebral vasospasm in rabbits. Injection of autologous arterial blood into cisterna magna resulted in significant vasospasm of the basilar arteries forty eight hours following injection. Concomitantly, the number of hematopoietic progenitor cells (CD34+ cells) and CD34+/Flk‐1+ cells, believed to be enriched in endothelial progenitor cells (EPCs), were significantly increased in the peripheral blood. The levels of the chemokine stromal cell‐derived factor‐1α (SDF‐1α), known to play a key role in the recruitment and retention of CXCR4+‐progenitor cells, significantly increased in the plasma of rabbits subjected to SAH. However, levels of SDF‐1α in the cerebrospinal fluid as well as the content of SDF‐1α in the spastic basilar arteries remained unaffected forty eight hours after SAH. In summary, cerebral vasospasm was accompanied by mobilization of hematopoietic progenitor cells and EPCs. We speculate that the pathogenesis of cerebral vasospasm following SAH may be mediated, in part, by impaired recruitment and homing of CXCR4+‐ progenitor cells.
Heteromultimeric Kv2.1/9.3 channels contribute to myogenic control of rat middle cerebral arterial (RMCA) diameter
Authors: Zhong Xi , Walsh Emma J , El‐Yazbi Ahmed , Cole William C
Published: June 2021

Cerebrovascular smooth muscle contractility plays a crucial role in control of cerebral arterial diameter and, thereby, blood flow regulation. K+ channels contribute to this regulation by controlling smooth muscle membrane potential (Em) and Ca2+ influx. Voltage‐dependent K+ channels containing Kv2 subunits are expressed in vascular smooth muscle, but their precise role and molecular composition have not been defined with certainty. Here, we tested if Kv2 subunits associate with silent subunits (Kv5, 6, 8 or 9) to form heterotetrameric channels that contribute to control of RMCA diameter. Stromatoxin‐1 (STX), a Kv2 channel blocker, caused vasoconstriction between 10 and 100 mmHg. However, the voltage‐activation range of homotetrameric Kv2 channels was positive to −40 mV and could not account for STX‐sensitive channel activity at 10 mmHg (Em < −45 mV). Real‐time PCR revealed predominant expression of Kv2.1 and Kv9.3. Comparison of the kinetic and voltage‐dependent properties of Kv2.1/Kv9.3 current (HEK293 cells) with those of native STX‐sensitive current provided evidence of functional identity. Our data indicate that Kv2.1/9.3‐containing channels play an important role in control of cerebral arterial diameter over a range of intra‐luminal pressure that is distinct from that previously reported for Kv1 and large conductance calcium‐activated K+ channels. (Funded by CIHR MOP‐13505)
Functional evidence for up‐regulated angiotensin converting enzyme (ACE) in coronary arterioles of rats on high fat diet
Authors: Feher Attila , Beleznai Timea , Labinskyy Nazar , Bagi Zsolt
Published: June 2021

Angiotensin converting enzyme (ACE) inhibitors prevent cardiovascular complications in cardiovascular diseases. We hypothesized that ACE, expressed in the wall of coronary resistance arteries is up‐regulated in obesity, which has an impact on regulation of coronary arteriolar diameter. In isolated, pressurized coronary arterioles (≈ 100 μm) angiotensin II (Ang II) elicited dilations that were not different between control (male Wistar rats on normal diet) and obese rats (male Wistar rats fed a 60% fat containing diet for 12 weeks). Dilations to Ang I, however, were significantly enhanced in coronary arterioles of obese rats, when compared to controls (64±7 vs. 20±4 %). Moreover, bradykinin elicited constriction in coronary vessels of obese rats (−9±6 %), whereas it dilated vessels in control animals (24±65). In the presence of the ACE inhibitor, captopril (10 μM), coronary dilations to Ang I were similar in the two groups (8±6 vs. 5±3 %). Whereas captopril restored dilations to bradykinin in obese rats (to 15±10 %), but it did not affect control responses (32±12 %). Collectively, we provide functional evidence for up‐regulated ACE in the coronary microvascular wall in obese rats fed a high fat diet. Up‐regulation of ACE is responsible for diminished dilation to bradykinin, that can be restored by ACE inhibition to enhance vasodilation of coronary arterioles in obesity. (AHA 0735540T and NIH NHLBI 43023)
Kudzu polyphenols decrease hyperinsulinemia and improve glucose control in ob/ob mice
Authors: Peng Ning , Prasain Jeevan K , Dai Yanying , Wyss J. Michael
Published: June 2021

Insulin resistance, impaired glucose handling, hypercholesterolemia, hypertension and obesity contribute to the metabolic syndrome. Recently, there has been a growing interest in the ability of dietary polyphenols to reduce the adverse effects of these factors. Kudzu root extract has a long history of use in traditional Chinese medicine, and our previous studies demonstrate that kudzu root extract provides cardiovascular benefits and improves glycemic and lipid control in spontaneously hypertensive rats. The present study tested whether dietary kudzu root extract also improves glycemic control and hyperinsulinemia in ob/ob mice. Male ob/ob and control mice (2‐month‐old) were placed on a 0.2 % kudzu containing diet or a control diet that was otherwise polyphenol free. After 3 and 8 months on the diets, plasma glucose concentration was lower in kudzu‐treated vs. control mice. Oral glucose tolerance tests (2 g/kg bw) demonstrated that in ob/ob mice dietary kudzu root extract decreased peak elevations in blood glucose (179 [kudzu diet] vs. 273 mg/dl [control diet] increases at 45 minutes). Plasma insulin concentration was lower in kudzu treated compared to control mice. The results indicate that dietary kudzu root extract improves glucose handling in ob/ob mice and suggest that kudzu polyphenols improve insulin resistance in this model.
Evaluation of the endocrine disrupting potential of the antimicrobial triclosan on early embryonic and larval development in zebrafish.
Authors: Good Ryan Kelly , Daggett Melissa A
Published: June 2021

Triclosan is a widely used chlorinated phenolic antimicrobial used in a variety of soaps, toothpastes, cosmetics, fabrics, and plastics. (Walker and Kimmel 2007). Triclosan is structurally similar to bisphenol A and dioxin, a well documented endocrine disruptor and potent carcinogen, respectively. Triclosan has recently been shown to have endocrine disrupting effects on multiple aquatic organisms and in human cells in culture, including effects on genes regulated by various estrogens, androgens, and thyroid hormones. Current concerns regarding the continued use of triclosan includes its increasing detection in urban streams and its ability to bioaccumulate in the lipid‐dense tissues of exposed organisms. Relevance to the importance of these concerns to humans includes, a report from 2008 demonstrating that 74.6% of human urine samples collected for testing contained triclosan in quantities ranging from 2.3 ug/L to 3, 790 ug/L. Triclosan, considered to be physiologically harmless, may have detrimental effects on organisms during early embryonic development. These effects may vary dramatically based on the timing of exposure. Statistically significant changes in variables such as eye diameter in zebrafish larvae can be observed when exposure times to sublethal concentrations of triclosan (200 ug/L) are prolonged through the first week of embryonic development. Preliminary results also indicate an effect on larval zebrafish heart rates. We hypothesize that this may be the result of an endocrine disrupting effect on the expression of receptors that control heart rate, such as the beta‐adrenergic and muscarinic receptors in the larval heart. Changes in several genes known to be regulated by estrogens, androgens, and thyroid hormones will be analyzed using by RT‐PCR and presented.
High fructose diet and its effect on gene regulation in rat heart
Authors: Ojaimi Caroline , Huang Harer , Kertowidjojo Elizabeth , Olson Lauren , Hintze Thomas H
Published: June 2021

High fructose consumption (FC) has been thought to be a contributing cause of insulin resistance, obesity, elevated LDL cholesterol and triglycerides, leading to metabolic and cardiovascular diseases. The effects of 21 days of a 60% purified fructose diet on gene expression, using Affymetric Rat Arrays, were investigated in cardiac tissues of female SD rats. Hemodynamic measurements showed significant increases in mean arterial pressure and insulin levels in FC. NO bioactivity was impaired by FC and this effect was reversed by tiron, which scavenges superoxide. These data suggest a role of superoxide in the heart during FC. The array data revealed 235 genes significantly regulated (p<0.05, ± 1.5 fold) in FC. The up regulated genes (n= 123) included caveolin 1 (limits NO production), PDE5A (increases NO breakdown), glucose‐fructose oxidoreductase, peroxisome proliferator activated receptor alpha, peroxisomal biogenesis factor 11 alpha, phosphatidylinositol 5‐kinase, granzyme A and stoning 2 (both shown to be expressed in diabetes). The down regulated genes (n= 112) included glucose‐6‐phosphate dehydrogenase, insulin‐like growth factor 2, N‐acetyltransferase 14, glutathione S‐transferase, ATPase, mitochondria ribosomal protein and UCP2. These results indicate that high fructose intake has a dramatic effect on the heart by regulating a large number of metabolic and energy producing genes.

Supported by HL‐PO1‐43023 & HL 50142.
Microarray Analysis Provides a Link between Adenylyl Cyclase Type 5 and Pressure Overload Hypertrophy
Authors: Park Misun , Park Ji Yeon , Tian Bin , Yan Lin , Lai Lo , Qiu Hongyu , Guellich Aziz , Iwatsubo Kosaku , Ishikawa Yoshihiro , Sadoshima Junichi , Vatner Dorothy E. , Vatner Stephen F.
Published: June 2021

Adenylyl cyclase type 5 and 6 (AC5 and AC6) are the major cardiac isoforms, but may affect cardiac pathophysiology differently. To investigate genes regulated by AC5 and AC6 regarding hypertrophy, we performed microarray‐based gene expression analysis of transgenic mice (TG) with cardiac specific overexpression of AC5 or AC6, and compared them with wild type with transverse aortic constriction (WT‐TAC). We detected a positive correlation of global gene expression profiles between AC5 TG and WT‐TAC, but not between AC6 TG and WT‐TAC. Baseline measures of AC5 high‐overexpression resulted in increased LV/BW (3.5±0.2) compared with WT (3.1±0.1) and AC6 TG (3.2±0.0). We found that commonly up‐regulated genes in both AC5 TG and WT‐TAC, but down‐regulated in AC6 TG were significantly, p<0.001, associated with extracellular matrix (ECM) organization and biogenesis. In addition hypertrophy related genes were up‐regulated in both AC5 TG and WT‐TAC, but not in AC6 TG. We confirmed those results by quantitative real‐time PCR. In summary, AC5 TG mice, even at baseline, have a similar gene expression profile to WT mice with TAC, which could explain the predisposition of AC5 TG to pressure overload hypertrophy. The microarray data also suggest that ECM related genes, which are regulated differently in AC5 and AC6 may be responsible for the adverse response of LV remodeling after pressure overload in AC5.
Dexamethasone Treatment Induces Cardiac Atrophy and Increased Proteasome Activity in MuRF1 KO mice
Authors: Hwee Darren Ting‐Cheung , Gomes Aldrin V. , Bodine Sue C.
Published: June 2021

Cardiac hypertrophy is an independent risk factor for a number of pathologies. Muscle ring finger‐1 (MuRF1) is an E3‐ubiquitin ligase that has been implicated in the regulation of cardiac mass. The objective of this study was to investigate the effect of dexamethasone (dex) treatment (3mg/kg) on cardiac mass in 6 month old female wildtype (WT) and MuRF1 knockout (KO) mice. Cardiac architecture and proteasome activity was analyzed following 28 days of dex treatment. Dex induced significant cardiac atrophy in MuRF1KO, but not WT mice. Echocardiography measurements revealed no difference in morphology or systolic function between the two groups. Dex‐treated MuRF1KO mice had significantly higher proteasome activity in the catalytic β1 and β5 subunits. Conversely, WT mice demonstrated significantly lower activity in the same catalytic subunits. These findings demonstrate that dexamethasone causes cardiac atrophy in 6 month old MuRF1 KO mice, and this atrophy may be due in part to increases in rates of protein degradation. This finding is contrary to previous reports that states that the absence of MuRF1 attenuates cardiac atrophy due to exogenous glucocorticoid treatment. This work was supported by funds from the Muscular Dystrophy Association.
Transgenic Rats with Cardiac Overexpression of alpha1A Adrenergic Receptors are protected from Myocardial Ischemia by a Nitric Oxide Mechanism
Authors: Zhao Xin , Vatner Dorothy E. , Park Misun , Yan Lin , IIsmaa Siiri , Graham Robert , Vatner Stephen F.
Published: June 2021

We determined whether cardiac overexpression of the alpha1A‐adrenergic receptor (α1A‐AR) affords protection against myocardial ischemia in a novel transgenic (TG) rat model where α1A‐ARs were overexpressed by 40‐fold in the heart. The effects of 30 min coronary artery occlusion and 3 hrs reperfusion (I/R) were examined in 7 TG and 7 WT rats. Infarct size (IF), expressed as a fraction of area at risk (IF/AAR), was determined by 2,3,5‐triphenyltetrazolium chloride staining, while the AAR was assessed using Evans blue dye. IF/AAR was significantly smaller (p<0.05) in TG (35±5%), compared to WT rats (50±2%). Expression (immunoblotting) of the inducible nitric oxide synthase (iNOS), a key mediator of second window preconditioning, was increased by 1.7‐fold in TG (n=5, p<0.05) compared to WT rats (n=5). Additionally total NOS activity was increased by 1.3‐fold in TG rat hearts (n=5, p<0.05). In WT rats, nitric oxide blockade with the NOS inhibitor, N‐nitro‐L‐arginine (L‐NNA) did not alter IF/AAR (54±2% vs 50±2%). In contrast, L‐NNA abrogated the cardioprotective effects observed in α1A‐AR TG rats, i.e., IF/AAR (53±2%) was no longer different from WT animals. Thus, in contrast to studies implicating α1A‐AR in first window preconditioning, our in vivo findings indicate that cardiac overexpression of α1A‐AR protects against I/R injury by a mechanism involving iNOS, a key mediator of second window preconditioning.
Kaempferol attenuates stress injury induced by oxLDL in human umbilical vein endothelial cells
Authors: Pi I , Tsai Kun‐Ling , Ou Hsiu‐Chung
Published: June 2021

Endothelial dysfunction caused by oxidized low‐density lipoprotein (oxLDL) plays a pivotal role in atherosclerosis. Kaempferol is a flavonoid present in various natural sources including apples, onions, leeks, citrus fruits, grapes, red wines, ginkgo biloba etc. Here we investigated the protective effects of kaempferol against oxLDL‐induced damage in human umbilical vein endothelial cells (HUVECs). The MTT assay showed that 2 hours pre‐incubation with kaempferol markedly restored the oxLDL‐induced viability loss in HUVECs in a concentration‐dependent manner. This effect was accompanied by a significant decrease in lactate dehydrogenase (LDH) release. Moreover, kaempferol imposed preventive effects on suppressing the production of reactive oxygen species (ROS), and restoring the activities of antioxidant enzyme superoxide dismutase (SOD). Pre‐incubation of kaempferol with HUVECs led to the reduction of apoptosis. Finally, kaempferol can efficiently prevent the disturbance of Bcl‐2 family protein, and triggered subsequent cytochrome c release into cytosol and activation of caspase‐3. Taken together, findings from our study suggest that kaempferol can effectively protect HUVECs against oxidative stress induced by oxLDL, which may be important for preventing atherosclerotic vascular disease.
Rhythmic mechanical deformation of the human forearm increases venous plasma [ATP] and ATP release
Authors: Crecelius Anne R. , Kirby Brett S. , Richards Jennifer C. , Voyles Wyatt F. , Dinenno Frank A.
Published: June 2021

Accumulating evidence indicates that circulating adenosine triphosphate (ATP) evokes vasodilation and assists in skeletal muscle blood flow regulation during exercise. Mechanical deformation of erythrocytes can stimulate ATP release in vitro, and we have demonstrated that rhythmic mechanical deformation of the forearm increases blood flow (FBF) via vasodilation. Thus, we tested the hypothesis that mechanical effects of muscle contractions increase [ATP] v and ATP release in vivo independent of changes in tissue metabolic demand. In 6 young adults, blood samples were obtained from a deep venous catheter and were mixed in stop solution to preserve [ATP] v for measurement. We measured FBF (Doppler ultrasound) and plasma [ATP] v and calculated forearm ATP release (FBF x [ATP] v) during rhythmic forearm compressions via a blood pressure cuff at 3 graded extravascular pressures (50, 100 and 200 mmHg). [ATP] v was significantly increased at each pressure compared with rest (range: 581–609 vs 237 ± 9 nmol/l; P < 0.05). Additionally, forearm compressions evoked a graded increase in FBF and thus ATP release was graded with extravascular pressure (P < 0.05). We conclude that rhythmic mechanical deformation of the forearm increases [ATP] v and ATP release, and that this mechanical effect of muscle contractions could contribute to the observed increases in [ATP] v and ATP release during exercise.

Supported by HL‐087952
Estimation of vascular properties using noninvasive measurements and a mathematical model of the systemic arteries
Authors: Rose William C. , Edwards Jonathan W. , Johnson David A. , Stillabower Michael E. , Edwards David G.
Published: June 2021

The estimation of vascular properties is useful for physiological and clinical assessment.

PURPOSE

The purpose of this study was to estimate vascular properties under different physiological conditions using noninvasive measurements and a mathematical model of the arterial circulation.

METHODS

Blood pressure waveforms were recorded by applanation tonometry at the radial and femoral arteries in 21 individuals under control conditions, during a cold pressor test, and after administration of sublingual nitroglycerin. A mathematical model of the arterial circulation was used to predict femoral artery pressure wave from measured radial artery pressure wave. Three model parameters were adjusted to minimize the difference between estimated and measured femoral pressure.

RESULTS

Resistance vessel diameter profile, arterial resistance, blood volume, and aortic pressure depended significantly on the perturbation given (ANOVA, p<0.01), but cardiac output and total arterial compliance did not (p>0.05). The root mean square difference between the predicted and measured femoral waveforms was 6.8 ± 4.5 mmHg.

CONCLUSIONS

Vascular mechanical properties estimated under different conditions had realistic values. Some but not all estimated quantities showed significant variation when physiological conditions were altered.

Supported by the University of Delaware Research Foundation.