bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential expression of phosphodiesterase 1‐5 in skeletal muscle microvessels: vessel types, sex, and reproductive maturation (664.4)
Authors: Wang Jianjie , Huxley Virginia 
Published: June 2021

Intracellular cyclic nucleotides (cAMP and cGMP) are critical second messengers to mediate various endogenous and exogenous factor‐induced vasomotion, angiogenesis, and vascular barrier function. Phosphodiesterases (PDEs), sole intracellular enzymes, hydrolyze cyclic nucleotides, and modulate cAMP‐ and cGMP‐dependent signaling events and corresponding functions. The objective of the study was to determine PDE1‐5 transcripts in skeletal muscle arterioles and venules and the role of sex and reproductive maturation in PDE1‐5 expression. Abdominal wall arterioles and venules were isolated from 4 groups of rats, adult males and females, juvenile males and females. Total RNA was extracted from arterioles and venules and reversely transcribed into first cDNA which was amplified by quantitative real‐time polymerase chain reaction using specific Taqman primers (real‐time RT‐PCR). Expression levels of PDE1‐5 were PDE5>PDE4>PDE1蠅PDE2>PDE3 in both arterioles and venules of 4 group rats (n=3‐7/gene/group, P<0.05) except PDE expression in venules of adult females was PDE4 greater than PDE5 (PDE4>PDE5>PDE1蠅PDE2>PDE3). In arterioles, greater expression of PDE3A and PDE3B were observed in adult males compared to adult females and juvenile males. In venules, PDE3BmRNA level was greater in adults than juveniles regardless of gender. In general, the findings demonstrate that PDE5, cGMP‐specific hydrolyzing enzyme, is predominantly expressed and the second most expression form is PDE4, cAMP‐specific hydrolyzing enzyme, in both arterioles and venules of 4 groups of rats except adult female venules (PDE4>PDE5). PDE3A and PDE3B exhibit sex‐specific and reproductive maturation‐specific difference.Grant Funding Source: NIH RO1HL078816
Pericyte‐endothelial junctional communication and calcium coupling (664.8)
Authors: Osborne Mathew , Bearden Shawn 
Published: June 2021

Pericytes (PCs) initiate and maintain the blood‐brain barrier phenotype of cerebral endothelium. Despite many studies referencing pericyte‐endothelial junctional (PEJ) communication, little is known of this signaling pathway. The purpose of this study was to determine if human brain endothelial cells (ECs) and PCs are functionally coupled. ECs and PCs were loaded with the calcium indicator fluo‐4 AM (Invitrogen) and treated with different reagents of varying concentrations (10‐4 to 10‐8 M). ECs and PCs both responded to acetylcholine, caffeine, and bradykinin (BK). Neither cell type responded to phenylephrine. Only PCs were stimulated by low concentrations (10‐7 M) of angiotensin 2. The magnitudes of responses to BK were higher in PCs than ECs at all concentrations tested (p< 0.05). To determine whether the PEJ mediates calcium coupling between cells, respective cell types were cultured on opposite sides of membrane inserts and loaded with fluo‐4 AM (0.4 µm pores; Transwell, Corning). BK concentrations ranging from 10‐5 to 10‐7 M elicited robust EC responses when applied to the PC side but were absent when PCs were removed. Immuno‐positive labeling of connexin 45 (Cx45), but not connexins 37, 40, or 43, in membrane pores is consistent with the presence of Cx45‐based gap junctional coupling at the PEJ. Human brain ECs and PCs form functional cell‐cell junctions, PEJs, which facilitate intercellular calcium signaling. This pathway may play a role in the regulation of blood‐brain barrier properties, possibly through Cx45‐dependent signaling.Grant Funding Source: NIH HL10654801
Obesity in aging exacerbates blood brain barrier disruption, neuroinflammation and oxidative stress in the mouse hippocampus: effects on expression of genes involved in beta‐amyloid generation and Alzheimer’s disease (665.1)
Authors: Tucsek Zsuzsanna , Toth Peter , Sosnowska Danuta , Gautam Tripti , Koller Akos , Sonntag William , Ungvari Zoltan , Csiszar Anna 
Published: June 2021

There is growing evidence that obesity has deleterious effects on the brain and cognitive function in the elderly. However, the specific mechanisms through which aging and obesity interact to promote cognitive decline remain unclear. To test the hypothesis that aging exacerbates obesityinduced cerebromicrovascular damage and neuroinflammation, we compared young (7 mo) and aged (24 mo) high fat diet‐fed obese C57BL/6 mice. Aging exacerbated obesity‐induced systemic inflammation and BBB disruption, as indicated by the increased circulating levels of pro‐inflammatory cytokines and increased presence of extravasated IgG in the hippocampus, respectively. Obesityinduced BBB damage was associated with microglia activation, up‐regulation of activating FcγRs and pro‐inflammatory cytokines and increased oxidative stress. Treatment of cultured primary microglia with sera derived from aged obese mice resulted in significantly more pronounced microglia activation and oxidative stress, as compared to treatment with young sera. Serum‐induced activation and oxidative stress were also exacerbated in primary microglia derived from aged animals. Hippocampal expression of genes involved in regulation of the cellular APP‐dependent signaling pathways, beta‐amyloid generation and the pathogenesis of tauopathy were largely unaffected by obesity in aged mice. Collectively, obesity in aging is associated with a heightened state of systemic inflammation, which exacerbates BBB disruption. The resulting neuroinflammation and oxidative stress in the mouse hippocampus likely contribute to the significant cognitive decline observed in aged obese animals.Grant Funding Source: supported by the American Heart Association and the American Federation for Aging Research
Aging exacerbates obesity‐induced impairment of neurovascular coupling and cerebromicrovascular rarefaction: implications for the pathomechanism of vascular cognitive impairment (665.2)
Authors: Tucsek Zsuzsanna , Toth Peter , Sosnowska Danuta , Gautam Tripti , Koller Akos , Ballabh Praveen , Sonntag William , Ungvari Zoltan , Csiszar Anna 
Published: June 2021

Obesity has deleterious effects on the brain and cognitive function in the elderly, however the mechanisms through which aging and obesity interact to promote cognitive decline remain unclear. We hypothesized that aging exacerbates obesity‐induced disruption of both functional and structural integrity of the cerebral microcirculation, contributing to a significant decline in higher brain function. To test our hypothesis we compared neurovascular coupling measured by CBF response above the barrel cortex to whisker stimulation, and cerebral capillary density by CD 31‐labeling of cerebral vessels in young (7 mo) and aged (24 mo) high fat diet‐fed obese C57BL/6 mice. High fat diet in young mice severely impaired CBF response to whisker stimulation (~50 % decrease), which was significantly exacerbated by aging. The high‐fat diet‐induced decrease in neurovascular coupling was significantly improved in both young and aged mice in the present of the NADPH oxidase inhibitor apocynin. Aged animals exhibited a significant decrease in cerebral capillary density, and the aging‐induced rarefaction was significantly exacerbated by high‐fat diet. These functional and structural pathological changes were associated with a decreased hippocampal‐dependent cognitive function in aged obese mice.In conclusion, aging exacerbates high fat diet‐induced decrease in neurovascular coupling via increased NADPH‐oxidase derived ROS production, and significantly enhances capillary rarefaction in the brain probably contributing to cognitive decline observed in aged obese animals.Grant Funding Source: Supported by the Oklahoma Center for the Advancement of Science and Technology
KCNQ and ERG channels control the rate of diastolic depolarization and electrical pacemaking frequency in lymphatic muscle (666.3)
Authors: Gui Peichun , Li Min , Hill Michael , Davis Michael 
Published: June 2021

The spontaneous contractions of lymphatic muscle cells are critical for propulsion of lymph. We investigated the ionic basis of pacemaking in the muscle layer of pressurized rat mesentery and mouse popliteal lymphatics using sharp electrodes and patch clamp methods. At very low pressures (<0.5 cmH2O) membrane potential was stable at ~ ‐42 mV, with infrequent action potentials (APs). At higher pressures APs fired at regular intervals, interspersed with slow diastolic depolarizations (DD) to a threshold of ~ ‐35 mV. Each AP consisted of a single 200‐ms spike, peaking at ~ +5 mV, followed by a 1.5‐sec plateau and after‐hyperpolarization to ~ ‐45 mV. Graded increases in pressure to 5 cmH2O led to graded increases in DD slope and AP frequency. The KCNQ inhibitors XE991 and linopirdine (1‐10 μM) increased DD slope without significantly changing AP height or duration. The selective Kv7.1 activator flupirtine (10 μM) decreased DD slope and AP frequency. In contrast, the ERG‐1 inhibitor E‐4031 (2‐6 μM) had little effect on frequency but prolonged AP duration due to multiple spikes with each AP. Based on PCR, the predominant KCNQ channel isoform was Kv7.1, with lesser expression of Kv7.4 (but not 7.2, 3 or 5). ERG‐1a and 1b (but not ERG‐2 or 3) channels were detected. We conclude that these K+ channel isoforms, which are typical of cardiac nodal cells, are important regulators of electrical pacemaking in lymphatic muscle.Grant Funding Source: NIH‐HL089784
Angiotensin II and ischemic preconditioning synergize to improve mitochondrial function while showing additive effects on ventricular post‐ischemic recovery (667.2)
Authors: Nuñez Rebeca , Castro Miriam , Javadov Sabzali , Escobales Nelson 
Published: June 2021

Recent studies indicate that the cardioprotective effects of ischemic preconditioning (IPC) against sustained ischemia/reperfusion (IR) can be replicated by angiotensin II (Ang II). However, it is not clear whether IPC and Ang II‐induced preconditioning (APC) act through similar mechanisms or synergize to enhance cardioprotection. In this study, Langendorff‐perfused rat hearts were subjected to IPC, APC or their combination (IPC/APC) followed by IR. IPC and less potently APC, induced cardioprotection as determined by significant increases in the percent recovery of the left ventricular developed‐pressure (LVDP), the first derivative of developed pressure (+dP/dt), and the rate pressure product (RPP) compared to controls. In absolute values, however, the post‐ischemic increase in +dP/dt and RPP were significantly higher for IPC/APC compared to IPC or APC. These effects were associated with normalization of ischemic contracture and lowered LDH release. IPC and/or APC also reduced infarct size and improved mitochondrial respiration and reduced mPTP opening. Notably, IPC/APC markedly increase the respiratory control index of mitochondria compared to IPC or APC. These effects were abrogated by pretreatment with losartan or chelerythrine. Therefore, our results demonstrate that IPC in combination with APC exerts additional cardioprotective effects on post‐ischemic recovery of cardiac function that are associated with improved mitochondrial respiration and attenuation of mitochondria‐mediated cell death.Grant Funding Source: Supported by NIH Grant SCIHL118669‐01A1 and NIH RCMI Program Grant G12RR‐03051
NFKB and CCR2 gene expression reflect long‐term but not acute inflammatory activation of peripheral blood mononuclear cells in patients with type 2 diabetes (669.3)
Authors: Horvath Peter , Radom‐Aizik Shlomit , Oliver Stacy , Zaldivar Frank , Galassetti Pietro 
Published: June 2021

In type 2 diabetes (T2D) cardiovascular complications are linked to chronic inflammation, including activated granulocytes, Gc, and monocytes, Mc, present in atherosclerotic lesions. In T2D, hyperglycemia and hyperlipidemia are common, and can acutely activate Gc/Mc surface markers in healthy, obese, and T2D subjects. T2D also displays marked variability of inflammatory status, possibly reflecting long‐term modulation (often involving gene expression). We therefore compared, during 4‐h i.v. infusions of glucose, lipids, or glucose +lipids, acute leukocyte surface marker activation and peripheral blood mononuclear cell (PBMC’s) expression of the key inflammatory genes NFKB and CCR2 (by RT‐PCR) in 5 healthy, 5 obese, and 5 T2D subjects. Unlike cell surface markers, NFKB and CCR2 expression was not affected by acute plasma metabolite changes in any group, but levels of gene expression paralleled overall systemic inflammatory activation, which in T2D varied considerably within subjects across study visits, likely reflecting long‐term inflammatory modulation. Our data suggests a two‐tiered inflammatory mechanisms in T2D, with acute metabolic changes immediately reflected on surface marker expression, and more prolonged stimuli affecting levels of leukocyte inflammatory gene expression.Grant Funding Source: Supported by NIH Grants P01HD048721 and UL1RR031985
Role of neutrophils in pulmonary vaso‐occlusion during sickle cell disease acute chest syndrome (669.6)
Authors: Bennewitz Margaret , Gladwin Mark , Sundd Prithu 
Published: June 2021

Sickle cell disease (SCD) is a hematological disorder that leads to sickling of red blood cells within the microcirculation. The sickle red blood cells (sRBCs) are not only less deformable, but also express α4β1, ICAM‐4, Sialyl Lewis X and glycolipids not expressed on non SCD‐RBCs. These rigid sRBCs can get sequestered in the microcirculation to cause painful vaso‐occlusive crisis (VOC) in SCD patients. In the lung, VOC can contribute to acute chest syndrome, which is a form of acute lung injury. Several factors including the pro‐adhesive sRBCs, the large marginated pool of neutrophils, and the hyper‐inflammatory state present in SCD can contribute to pulmonary VOC. Although neutrophil‐RBC‐endothelium interactions are known to play a role in systemic VOC, the cellular mechanism that drives pulmonary VOC remains unknown. Intravital study of the lung microcirculation of live BERK or Townes SCD mice is conducted using two‐photon microscopy. Prior to observation, mice are challenged with lipopolysaccharide or PBS to cause lung inflammation and administered (iv) with fluorescent anti‐mouse Gr‐1 and Ter‐119 antibodies to label circulating neutrophils and RBCs, respectively. Vaso‐occlusion is defined as cellular aggregation and stasis of blood flow within the lumen of pulmonary capillaries. Preliminary results reveal that circulating macro‐aggregates of neutrophils and RBCs may play a role in pulmonary VOC.Grant Funding Source: Supported by AHA, VMI startup account, and NIH Pulmonary T32 training grant
Strategical steering of the immune system: induction of leukocyte vascular chaperoning increases functional blood flow responses in ischemic muscle (670.6)
Authors: Vagesjo Evelina , Christoffersson Gustaf , Korsgren Olle , Essand Magnus , Holm Lena , Phillipson Mia 
Published: June 2021

BACKGROUND: The role of leukocytes in angiogenesis is emerging. This study investigates leukocytes recruited to ischemic muscle and if vascular repair can be accelerated by induction of local chemokine production.METHODS: Plasmids encoding CCL2 or CXCL12 were expressed in the cremaster muscle or in ischemic hindlimb muscle in wild‐type, CX3CR1‐GFP and RAGE‐/‐ mice. Functional tissue perfusion was measured during heat‐induced hyperemia in the hindlimb using Laser Doppler Flowmetry or in foot pads using Laser Speckle Contrast Analysis. The role of macrophages was challenged by clodronate liposome depletion. Vascular function, leukocyte phenotypes and position were studied in single vessels of ischemic muscle using intravital confocal microscopy. Effects of chemokine overexpression in the injured muscle on leukocyte subsets, perfused vessels and vascular densities were quantified.RESULTS: Plasmid expression peaked at day 2 and was detected for 4 weeks following injection. Ischemic limbs expressing pCXCL12 showed improved heat‐induced hyperemia response and higher density of perfused capillaries 3 and 7 days post ischemia induction. pCXCL12‐expressing ischemic muscles contained increased number of macrophages (CX3CR1+F4/80+), which were polarized towards the pro‐angiogenic phenotype (F4/80+MRC1+) and found to chaperone perfused vessels. The importance of this observation was demonstrated in mice depleted of macrophages, in which functional blood flow response was not improved by pCXCL12. The blood flow effect of pCXCL12 was blunted in RAGE‐/‐ mice despite increased M2 macrophage density, indicating downstream RAGE involvement. Overexpression of pCCL2 did not expand the leukocyte population or improve vascular functional blood flow in this system.CONCLUSION: Overexpression of pCXCL12 but not pCCL2 in ischemic muscle accelerates restoration of functional blood flow responses by retaining macrophages chaperoning the vasculature.
Role of neutrophils and β2 integrins in platelet extravasation in corneal limbal venules following epithelial wound injury (671.10)
Authors: Li Zhijie , Smith C , Gagen Debjani , Lam Fong , Burns Alan , Rumbaut Rolando 
Published: June 2021

Corneal epithelial wound injury in the mouse results in an acute inflammatory response in the surrounding peripheral limbal microvessels. We showed previously that in wild‐type mice neutrophils (PMNs) and platelets accumulate at the inflamed limbus in a co‐dependent manner and approximately 50% of platelets are evident in the extravascular space; the mechanisms by which platelets extravasate are unclear. To determine the role of PMNs and β2 integrins on platelet extravasation, we quantified platelet recruitment in corneal vessels in mice after antibody‐induced depletion of neutrophils (anti‐Ly6G); control mice received isotype control antibody. We also compared extravascular platelet numbers in wild‐type mice and mice deficient in CD18. Anti‐Ly6G antibodies decreased total platelet numbers in corneal limbal vessels 24 hours after epithelial injury (from 141 ± 15 to 66 ± 16 platelets per field, p<0.05) and reduced the relative proportion of extravascular platelets (from 56 ± 5 % to 9 ± 1%, p< 0.001). Similarly, mice deficient in CD18 had a substantial decrease in extravascular platelets following corneal injury. Platelet‐PMN contact was evident in the intravascular and extravascular space by immunofluorescence and electron microscopy. These studies demonstrate that PMNs and β2 integrins contribute to platelet extravasation from corneal limbal vessels following epithelial wound injury.Grant Funding Source: Supported by R01 HL‐ 116524, and a Merit Review Grant from The Department of Veterans Affairs
A mouse model to assess neointimal formation following endothelial denudation and bioresorbable stent implantation (671.12)
Authors: Nehzati Ashkon , Davalian Dariush , Magana Jesus , Consigny Paul , Cardinal Trevor 
Published: June 2021

Restenosis is a common response to bare‐metal stent implantation occurring in 16‐44% of patients. Drug‐eluting stents can reduce restenosis, but late‐stent thrombosis occurs in 0.4‐0.6% of patients following cessation of anti‐platelet therapy. Bioresorbable stents may limit both restenosis and late thrombosis. The goal of this work is to develop a mouse model that can be used to assess neointimal formation in response to injury and/or bioresorbable stent implantation.The endothelium was denuded in the abdominal aorta of C57Bl/6 mice using a nitinol device inserted into the femoral artery and confirmed using Evans Blue staining and histopathology. Bioresorbable stent implantation was performed by placing a stent (polymeric coil) in a PE tube, and advancing it into the abdominal aorta. Using a wire advancer, the stent was placed while withdrawing the tube simultaneously.Staining and histopathology revealed endothelial denudation of the abdominal aorta between the renal arteries and iliac bifurcation during acute procedures and increases in wall thickness and cellularity over 28 days. Direct visualization revealed that the polymeric stent can be delivered to area of endothelial denudation with no migration or distal embolization.In summary, we created a mouse model to assess neointimal formation following endothelial denudation and/or bioresorbable stent deployment. In the future, this model can be used to characterize gene expression and assess specific molecular pathways that contribute to restenosis and thrombosis.
Increased oxidative stress enhances endocannabinoid tone (671.13)
Authors: Matthews Anberitha , Borazjani Abdolsamad , Wang Ran , Ross Matthew 
Published: June 2021

Cardiovascular disease (CVD) has been characterized as a chronic inflammatory disease that has become prevalent in industrialized societies. NADPH oxidase contributes to atherosclerosis through the activation of macrophages leading to the internalization of oxidized low‐density lipoproteins (oxLDL). Chronic inflammation is caused in part by monocytes invading the vasculature leading to the formation of lipid‐laden macrophage foam cells with increased flux of oxygen/nitrogen radicals and subsequent chemical modification of extracellular LDL. Endogenous cannabinoids (eCB), such as 2‐arachidonoylglycerol (2‐AG), may be a link between oxidative stress and atherosclerosis. We hypothesize that 2‐AG biosynthesis is enhanced following CD36 ligation by oxLDL and subsequent activation of diacylglycerol lipase β (DAGLβ), the key biosynthetic enzyme of 2‐AG, via upregulated NADPH oxidase activity. Treatment of murine J774 macrophages and human THP1 macrophages/monocytes with either extracellular xanthine/xanthine oxidase or phorbol 12‐myristate 13‐acetate (PMA) caused an increase in superoxide (O2•−) levels and enhanced 2‐AG biosynthesis (2.3‐fold and 2.8‐fold, respectively) compared to vehicle controls. These treatments were not cytotoxic. These data suggest a significant positive correlation between oxygen radical flux and 2‐AG biosynthesis in macrophages. Increased 2‐AG biosynthesis may be an adaptive response to elevated oxidative stress because of antioxidant and anti‐inflammatory actions associated with this bioactive lipid. Therefore, the pathogenesis of atherosclerosis within the vessel wall intima may be reduced by enhancing eCB tone.Grant Funding Source: Supported in part by NIH R15ES015348‐02
The effect of EPA and DHA on platelets treated with multiple agonists found in the thrombus core (671.3)
Authors: McCue Betsy , Shaull Lance , Kollasch Anna , Ye Shaojing , Whiteheart Sidney , Larson Mark 
Published: June 2021

The omega‐3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been consistently associated with reduced platelet function, and more recently, with impaired thrombin generation. However, almost all studies to date have focused on how EPA and DHA alter platelet physiology in response to monotypic agonist stimulation. This reductionist approach does not recapitulate the complex chemical environment found in a developing thrombus. Therefore, we asked if platelets treated with multiple agonists like those found in the thrombus core would also display EPA and DHA‐mediated inhibition. We found that optical aggregometry and dense granule secretion was diminished after EPA and DHA incorporation in platelets stimulated with the core clot agonists. We also noted a reduction in both the protein content of platelet lipid rafts and thrombin generation after core agonist stimulation, consistent with our earlier observations. Transmission electron micrographic imaging also established that EPA and DHA‐treated platelets showed moderate ultrastructural malformations after core agonist treatment. These results all suggest that EPA and DHA can abrogate platelet signaling responses within the core of a developing thrombus, further illustrating the potential health benefits of increased EPA and DHA intake.Grant Funding Source: Supported by an Institutional Development Award (IDeA) from the NIH/NIGMS, #P20GM103443