bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limb specific differences in vasomotion response to varying rates of local heating
Authors: Del Pozzi Andrew Thomas , Miller James T , Hodges Gary J 
Published: November 2023

We examined skin blood flow (SkBF) and vasomotion in the forearm and leg using laser‐Doppler fluxmetry (LDF) and spectral analysis to investigate endothelial (0.0095 – 0.021 Hz), sympathetic (0.021 – 0.052 Hz), and myogenic (0.052 – 0.145 Hz) activity in response to slow (0.1°C·10 s−1) and fast (0.5°C·10 s−1) local heating. Based on previous investigations we hypothesized that both limbs would respond with higher initial and sustained vasodilator activity in response to the fast‐rate of heating. Secondly, we hypothesized that the vasomotion responses would differ between the forearm (greater sympathetic activity) and the leg (greater endothelial activity). At 33°C (thermonuetral) endothelial activity was higher in the legs than the forearms (P ≤ 0.02). Fast‐heating increased SkBF more than slow heating in both the forearm (169 ± 30 mV vs. 151 ± 28 mV; P = 0.037) and the leg (159 ± 32 mV vs. 130 ± 12 mV; P = 0.002). At onset of 42°C, endothelial activity was increased in both regions during the fast‐heating protocol (P = 0.009 forearm; P = 0.02 leg). There was greater sympathetic activity observed in the forearm (7.8825 mV2/Hz) than the leg (2.5 mV2/Hz) during the first 5 min of the fast‐heating (P = 0.004) protocol. With prolonged heating (42°C for 35 min), endothelial activity was higher following fast heating compared to slow heating in both the forearm (11.855 vs. 4.828 mV2/Hz; P = 0.01) and leg (9.338 vs. 4.319 mV2/Hz; P = 0.011). In the skin of the forearm compared to the leg, endothelial (11.855 vs. 9.338 mV2/Hz; P = 0.047), myogenic (1.6055 vs. 1.2305 mV2/Hz; P = 0.049), and sympathetic (9.126 vs. 5.526 mV2/Hz; P = 0.046) activity were higher for the fast heating protocol. These results confirm regional differences in the response to local heating and suggest that the increase in SkBF in response to rapid local heating at both the forearm and leg sites is due to increased endothelial and sympathetic activity.Support or Funding Informationnone
Ossified Bone Marrow Blood Vessels, Trabecular and Cortical Bone Properties and Hematological Parameters in 6‐ and 18‐month‐old Fischer 344 Rats
Authors: Guderian Sophie , Lee Seungyong , McLane Mary Ann , Prisby Rhonda 
Published: November 2023

BACKGROUNDWe previously discovered ossification of bone marrow blood vessels (BMBV) in 6‐ and 24‐month‐old F‐344 rats, whereby some BMBV had converted into bone (Prisby, 2014). Recently, we described the presence of ossified BMBV as early as 1 month in F‐344 rats, suggesting that this vascular pathology begins early in life (Guderian, ASBMR 2015). Since bone marrow is the site for blood cell production and blood cells access the peripheral circulation via blood vessels, we sought to assess whether BMBV ossification coincides with declines in red and white blood cell count. We examined BMBV ossification, trabecular and cortical bone properties, and hematological parameters as a function of advancing age.METHODSLeft femora and whole blood samples were collected from young (6 mon; n=5) and aged (18 mon; n=5) male Fischer‐344 rats. Bone microarchitecture (BV/TV, %; Tb.N,/mm2; Tb.Th, mm & Tb.Sp, mm) and trabecular bone density (g/cm3) in the distal femora and ossified vessel volume (OsVV) and ossified vessel density (g/cm3) in femoral shafts were assessed by mCT (Scanco Medical). Cortical bone parameters (cortical thickness, μm; cortical bone density, g/cm3 & cross sectional moment of inertia [CSMI, mm4]) were also compared between groups. SMI was compared between trabecular bone and ossified BMBV. Complete blood counts were determined with a Coulter ® Ac•T diffTM Analyzer (Beckman).RESULTSBody mass (p<0.05) increased with age. Trabecular BV/TV tended to be lower (p=0.056) in young (20.5±1.2%) vs. aged (25.0±1.5%) rats, resulting from decreased (p<0.05) Tb.Th (young, 68.84±2.14 mm vs. old, 89.12±2.65 mm). OsVV was similar between young (0.033±0.0120%) and aged (0.040±0.006) rats. SMI values for OsVV (young, 3.5±0.1 and old, 3.8±0.1) were indicative of cylindrical vs. the plate‐like shapes of trabecular bone (young, 1.8±0.1 and aged 0.8±0.1). Trabecular (young, 908.8±3.6 g/cm3 vs. aged, 935.2±3.6 g/cm3) and cortical (young, 1184.1±5.9 g/cm3 vs. aged, 1237.6±7.8 g/cm3) bone was denser with age (p<0.05). Trabecular bone density was similar to ossified vessel density (young, 882.1±18.9 g/cm3 vs. aged, 923.4±4.7 g/cm3). Cortical bone thickness (young, 724±3 μm vs. aged, 805±26 μm) and CSMI (young, 13.8±0.9 mm4 vs. aged, 22.2±1.8 mm4) were increased (p<0.05) with age. The complete blood count variables (e.g., WBC, RBC, Hgb, Hct, etc.) did not differ between groups.CONCLUSIONSOsVV and hematological parameters did not differ between 6‐ and 18‐month old rats. However, trabecular BV/TV, trabecular and cortical bone density, cortical bone thickness and CSMI were higher in 18‐month‐old animals.Support or Funding InformationSupported by National Institutes of General Medical Sciences (P20 GM103446; Project PI: R. Prisby)
A splice variant of smooth muscle myosin phosphatase regulatory subunit tunes arterial reactivity and suppresses response to salt loading
Authors: Reho John , Kenchegowda Doreswamy , Asico Laureano D. , Fisher Steven 
Published: November 2023

Nitric oxide (NO) and reactive oxygen species (ROS) through activation of cGMP‐dependent protein kinase (cGK1a) activate smooth muscle Myosin Phosphatase (MP), thereby causing de‐phosphorylation of myosin and vasorelaxation. cGK1a is targeted to the MP regulatory subunit (Mypt1) via Leucine Zipper (LZ)‐mediated hetero‐dimerization. Isoforms of Mypt1 with variable presence of the C‐terminal LZ motif are generated by alternative splicing of the 31 nt Exon24 (E24). We have demonstrated that the expression of these isoforms is vessel‐specific, developmentally regulated and modulates in disease. Based on correlations of expression and function and biochemical assays we have proposed a model in which Mypt1 E24 splicing tunes arterial sensitivity to NO/ROS mediated vasorelaxation. To directly test this model LoxP sites were inserted in introns flanking E24 and bred into smMHCCreER for Tamoxifen‐inducible and smooth muscle‐specific deletion of E24 from Mypt1 (E24 cKO). This converts Mypt1 to the E24‐ splice variant coding for the LZ+ isoform. We generated an allelic series of mice: Cre+ with 0, 1 or 2 floxed alleles and measured blood pressure (BP) by telemetry and arterial function by wire myography. E24 cKO had significantly lower systemic BP with no difference between hetero‐ and homo‐zygotes. There was no effect on the circadian variation in BP. Vasorelaxation of 1st order mesenteric arteries (MA1) to the NO donor DEA/NO, and its 2nd second messenger cGMP in permeabilized and calcium clamped arteries, was markedly enhanced again with no difference between hetero‐ and homo‐zygotes. The only parameter in which these mice differed was a marked suppression of force generation to the a‐adrenergic agonist phenylephrine (PE) in the homozygotes. This was specific to this signaling pathway as there were no changes in force generation to the thromboxane analogue U46619, Angiotensin II, KCl depolarization or calcium. Two weeks of salt loading (4% sodium diet) increased MA1 force generation to PE in wild type mice. This response was abrogated y in the homozygous Mypt1 E24 cKO mice. We conclude that Mypt1 E24 splice variants tune arterial sensitivity to vasodilators such as NO/ROS signaling though cGK1 activation of MP. Targeting of therapies to the contractile apparatus of microvascular smooth muscle may have salutary effects in the treatment of hypertension and other cardiovascular diseases in which increased vascular resistance has a dominant role.Support or Funding InformationNIH R01‐HL066171, 7R37‐HL023081, T32‐HL072751
Spectral analysis measured in cooling‐evoked hemodynamic perturbations of rats indicates endogenous nitric oxide facilitating sympathomyogenic oscillations
Authors: Tung Che‐Se , Liu Yia‐Ping , Lin Yi‐Hsien , Lin Yu‐Chieh , Lee Po‐Lei 
Published: November 2023

Rapid cooling stress (CS) elicits hemodynamic perturbations (CEHP). We previously reported that CEHP is highly relevant to the sympathetic activation and nitric oxide (NO) production. This study identifies the role of NO in CEHP. Conscious rats were pretreated with the NO‐synthase inhibitor (L‐NAME) alone or superimposition of sympatholytic interventions using hexamethonium (HEX) or guanethidine (GUA), and then subjected to a CS trial. Cardiovascular indices were monitored via an implanted telemetric device throughout experimental protocol. The analyses included measurements of blood pressure (BP); heart rate (HR); the variability of BP and HR (BPV, HRV); spectral powers and coherence linkage at very‐low, low, and high frequency regions (VLF: 0.02–0.2 Hz, LF: 0.2–0.6 Hz, and HF: 0.6–3.0 Hz); and dicrotic notch (Dn). When compared with control vehicle under CS, the L‐NAME alone (a) increased BP, Dn, VLFBPV, VLFHRV, LFHRV, and HFHRV but decreased HR, HFBPV, and LF/HF ratio; (b) converted negative correlation into positive correlation for LF pair (LFHRV/LFBPV) and VLF pair (VLFHRV/VLFBPV); and (c) enhanced the coherence linkage between BPV and HRV at the LF region but weakened them at the HF region. We also noted divergent patterns of spectra responsiveness to HEX or GUA superimposed on L‐NAME. The effects of HEX+L‐NAME versus GUA+L‐NAME, particularly on LF and VLF between BPV and HRV, indicated an essential role for a functional adrenal medulla to release epinephrine under CS. Our results indicate that endogenous NO play an inhibitory role on the sympathovascular activation and subsequently the myogenic vascular oscillations in CEHP.Support or Funding InformationGrant in aid: the Ministry of Science and Technology (MOST 102 &103‐2320‐B‐350‐001) and the National Defense Medical Center (MAB101‐40; MAB‐102‐81), Taiwan, R.O.C.
Over‐Expression of Osteopontin Significantly Increases Cardiomyoycte Size
Authors: McBride Martin , Downie Laura , Martin Tamara , McClure John D , Nicklin Stuart , Graham Delyth 
Published: November 2023

IntroductionThe stroke‐prone spontaneously hypertensive rat (SHRSP) is an excellent model of human cardiovascular disease and develops increased left ventricular mass index (LVMI) in young animals, prior to the onset of hypertension. We identified a quantitative trait locus (QTL) for LVMI on chromosome 14. Using a combination of chromosome 14 congenic strains and heart gene expression profiling, we identified positional candidate genes within the chromosome 14 congenic interval, including osteopontin. The aim of this study was to validate osteopontin as a functional candidate gene affecting cardiomyocyte size.MethodsH9c2 myoblast cells were transfected with osteopontin cloned into pcDNA1 (3ug), using Xfect transfection reagent. Cells were seeded 24hrs prior to transfection at a seeding density of 3.4×104 cells/well, conditioned media was obtained from cells post‐transfection and incubated with fresh H9c2 cells for 48hrs. EVOS (crystal violet) microscopy images were analysed using ImageJ software. Cell data was analysed using ANOVA with Dunnett's post hoc test.ResultsSignificantly increased osteopontin mRNA expression was confirmed in transfected cells by qRT‐PCR (RQ cells 1.0±0.09, pcDNA1 2.0±0.31, SHRSP osteopontin cDNA 58.2±4.55*, *p<0.001 compared to cells only). Osteopontin transfected cells were significantly increased compared to cell and pcDNA1 transfection controls (cells 71.4±3.4, X‐fect 74.0±1.4, pcDNA1 81.4±2.1*, SHRSP osteopontin cDNA 138.1±3.1*, *p<0.001 compared to cell control). Conditioned media from each group was prepared and added to cells with a significant increase in osteopontin transfected cells, compared to controls (cells 67.3±1.1, X‐fect 65.5±0.8, pcDNA1 67.9±1.1, SHRSP osteopontin cDNA 145.3±3.0*, *p<0.001 compared to cell control).ConclusionThis data confirms that over‐expression of osteopontin increases cell size in the H9c2 model. This confirms osteopontin as a positional and functional candidate gene underlying the left ventricular mass index QTL on chromosome 14 in the SHRSP rat.Support or Funding InformationBritish Heart Foundation and the BBSRC
Propofol dialates coronary arteries in Vitro via Endothelial TRPA1 and TRPV1 Channels
Authors: Roy Pritam Sinha , Bratz Ian , Damron Derek 
Published: November 2023

IntroductionTransient receptor potential (TRP) ion channels have emerged as key regulators of vasomotor tone. Propofol is an intravenous anesthetic with numerous benefits, but also associated with side effects such as hypotension and acute pain upon infusion. Our objective is to determine the role of TRPA1 and TRPV1 ion channels on mediating propofol‐induced vasodilation of mice coronary arteries in vitro.MethodsHearts were excised from anesthetized mice and coronary arterioles were dissected from control C57Bl/6J, TRPA1−/−, TRPV1−/− and double‐knockout mice (TRPAV−/−). Isolated microvessels were cannulated and secured in a temperature‐controlled chamber and allowed to equilibrate for 1 hr. Vasoreactivity studies were performed in pre‐constricted microvessels to assess the effect of propofol. Also, immunoblot analysis and immunostaining were performed on mice coronary artery endothelial cells (MCAECs). Intracellular Ca(2+) concentration was measured in individual MCAECs via fluorescence microscopy.ResultsIn vitro, propofol‐induced relaxation was unaffected in TRPV1−/− vessels, markedly attenuated in TRPA1−/− vessels and abolished in TRPAV−/− vessels. Immunoblot and immunocytochemical analysis detected TRPA1 and TRPV1 channel proteins in MCAECs. Moreover, single application of propofol and capsaicin caused an increase in intracellular [Ca]2+ in MCAECs, that was abolished in presence of the TRPA1 antagonist, HC‐030031 and and TRPV1 antagonist capsazepine.DiscussionOur coronary in vitro data indicate that TRPA1 is directly involved whereas TRPV1 appears to be indirectly involved because deletion of TRPV1 alone has no observable effect on propofol‐induced depressor response.Support or Funding InformationHL‐65701 from the NationalHeart, Lung and Blood Institute, Bethesda, Maryland.
SERCA inhibition attenuates medial thickening in an organ culture model of coronary artery disease
Authors: Rodenbeck Stacey Dineen , Barnard April L , Sturek Michael 
Published: November 2023

Atherosclerotic coronary artery disease (CAD) involves de‐differentiation of coronary smooth muscle (CSM) from a quiescent, contractile phenotype to a proliferative, migratory phenotype. We tested the hypothesis that sarco‐endoplasmic reticulum Ca2+ ATPase (SERCA) function is causal in CSM transition from contractile to proliferative. We measured proliferation with immunohistochemical analysis of Ki‐67 expression in both mild and severe atherosclerotic plaques. Ki‐67 expression peaks early in CAD progression, dropping off in severe CAD, likely because CSM either further differentiate into osteogenic CSM or become apoptotic. We concurrently examined SERCA function with fura‐2 assessment of caffeine‐induced sarcoplasmic reticulum (SR) Ca2+ store release and subsequent recovery. SERCA function is elevated in mild, early CAD and decreases in more advanced, severe CAD, mirroring Ki‐67 expression patterns. We cultured coronary arterial segments in DMEM with 180 mg/dL glucose and 20% fetal bovine serum for fourteen days, in the presence and absence of the selective SERCA inhibitor, cyclopiazonic acid (CPA). Initial results indicated that CPA treatment completely prevented culture‐induced medial thickening as assessed by histological staining. CSM were enzymatically dispersed and loaded with fura‐2/AM. CPA was absent from the dispersal and experimental solutions. SR Ca2+ store release and subsequent recovery below baseline levels were increased in CSM from CPA‐treated arteries, suggesting that functional inhibition induces of SERCA expression. We will examine SERCA and Ki‐67 expression in future studies to further examine the role of SERCA in the contractile‐to‐proliferative transition in atherosclerotic CAD.Support or Funding InformationNIH HL062552, IUSM CECARE, AHA 15PRE25280001
CTRP3 Prevents ETOH‐ Induced Hepatocyte Apoptosis
Authors: Dunlay Samantha , Peterson Jonathan M 
Published: November 2023

Alcohol abuse is the third leading cause of preventable death in the United States. Our lab works with the novel protein C1q TNF Related Protein (CTRP3), which is secreted from adipose tissue and circulates in the blood stream. Our past lab experiments show that CTRP3 prevents nonalcoholic fatty alcoholic liver disease. Nevertheless, the effects of CTRP3 on alcoholic fatty liver disease (AFLD) are still unknown. Our lab to date, has determined that CTRP3 prevents alcohol‐induce hepatocyte (liver cell) death. The purpose for this project is to understand how. Previous research has demonstrated that ethanol consumption increases apoptosis (programmed cell death) in hepatocytes through an inappropriate elevation in apoptotic signaling. Our working hypothesis is that CTRP3 prevents ethanol‐induced hepatocyte cells death by suppressing ethanol‐induced elevations in pro‐apoptotic signaling. To test our hypothesis we examine the effects of ethanol plus/minus CTRP3 treatment on the Bcl‐2 family of apoptotic regulatory proteins. The Bcl‐2 family can either induce (pro‐apoptotic) cell death or inhibit cell death (anti‐apoptotic).MethodsHepatocytes were treated with ethanol (100 mM) plus/minus recombinant CTRP3 and Bcl‐2 family protein content was determined through western blot analysis. We measured the specific apoptotic regulator proteins: Bcl‐2‐associated X protein (BAX), which is pro‐apoptotic, and B‐cell lymphoma 2 (BCL‐2) and (BCL‐XL), which are anti‐apoptotic. Western blots were performed using standard techniques; briefly, protein samples are separated by size through SDS‐PAGE (PolyAcrylamide Gel Electrophoresis). The proteins are then transferred to a nitrocellulose membrane and relative protein concentrations are detected by chemiluminescence.Resultsethanol treatment increases the amount of BAX and decreases the amount of BCL‐XL but not BCL‐2 protein content in the hepatocytes. However, treatment with CTRP3 stopped the ethanol‐induced elevations to BAX and reductions in BCL‐XL. In conclusion this data supports our hypothesis that CTRP3 prevents ethanol‐induced hepatic cell death.Support or Funding InformationEast Tennessee State University RDC: E82262NIAAA: R03AA023612
Loss of pancreatic Mig6 improves glucose homeostasis during diet‐induced obesity
Authors: Olivos Naomie , Fueger Patrick T 
Published: November 2023

In response to nutritional overload, functional beta cell mass normally expands to compensate for diet‐induced insulin resistance, thereby preserving glucose homeostasis. In the pathogenesis of type 2 diabetes (T2D), however, the compensation is insufficient, as beta cell dysfunction and destruction develop, leading to a mismatch between functional beta cell mass and insulin sensitivity. Thus, targeting beta cell proliferation as well as beta cell secretory capacity (i.e., function) and survival could prevent the onset of the disease. We have been investigating the impact of the elevated levels of mitogen inducible gene 6 (Mig6) in beta cells during glucolipotoxicity, as this milieu is thought to contribute to T2D. Mig6 is an adaptor protein that impairs EGFR signaling, a critical cell survival and proliferation pathway. Thus, we hypothesized that ablating Mig6 would fortify functional beta cell mass and preserve glucose homeostasis during diet‐induced obesity and insulin resistance. To this end, we compared mice lacking pancreatic Mig6 (PKO) and their wild‐type (WT) littermates fed either a low fat or high fat diet. No observable phenotypic differences were observed between either genotype fed the low fat diet. High fat feeding increased body mass and decreased glucose tolerance in WT mice, despite a robust increase in beta cell cross‐sectional area (as an index of beta cell mass). In contrast, high fat‐fed PKO mice had improved glucose tolerance compared to WT littermates, despite no increase in beta cell cross‐sectional area. These data suggest that either PKO mice are protected from diet‐induced insulin resistance or their beta cell function is enhanced to the extent to be able to compensate for systemic insulin resistance. Therefore, blocking the actions of Mig6 and thereby enhancing EGFR signaling could represent a novel strategy for preventing or delaying the progression to T2D.Support or Funding InformationNIH grant DK099311 (PTF)
α1A‐Subtype Adrenergic Therapy is Beneficial for Failing Right Ventricle (RV)
Authors: Cowley Patrick M , Wang Guanying , Joshi Sunil , Lovett David H , Simpson Paul C , Baker Anthony J 
Published: November 2023

Compared to non‐failing RV, we reported that failing RV had an increased inotropic response to stimulation of α1‐adrenergic receptors (α1‐ARs). Recently, we found that a single subtype (α1A) was responsible. We hypothesized that increased α1A‐subtype signaling is beneficial in RV failure and a potential therapeutic target. Studies in several laboratories suggest that chronic α1A‐subtype stimulation has a beneficial effect on LV function in multiple heart failure models. However, no studies have investigated chronic α1A‐subtype stimulation in the setting of RV failure.GoalDetermine if α1A‐subtype adrenergic therapy is beneficial for failing RV.MethodsWe used tracheal instillation of the fibrogenic antibiotic bleomycin in mice to induce pulmonary fibrosis, pulmonary hypertension, and RV failure within 2 wk. Mice were treated concurrently using osmotic mini‐pump infusion with either a low dose of the α1A‐subtype agonist A61603 (10ng/kg/day) or saline (vehicle controls). We assessed multiple readouts of cell injury in failing RV and determined if these were improved by A61603 therapy.ResultsMultiple readouts of cell injury in failing RV myocardium were markedly attenuated by A61603 therapy. Specifically, the Table summarizes that the level of serum troponin I (TnI) was significantly increased in the bleomycin RV failure model and this increase was prevented by A61603 therapy. Myofilament force development was significantly reduced in failing RV, and this decrease was prevented by A61603 therapy. Two isoforms of matrixmetalloproteinase‐2 (MMP‐2), which are associated with cell injury, were increased in failing RV, and these increases were prevented by A61603 therapy. Finally, bleomycin‐induced pulmonary fibrosis was associated with markedly increased lung weight, and this increase was not abolished by A61603 therapy, suggesting that the beneficial effect of A61603 therapy on the RV did not occur via a beneficial effect on the bleomycin model of lung injury. Preliminary studies suggest that the beneficial effect of A61603 therapy involves a reduction in the level of oxidative stress.ConclusionChronic therapy with the α1A‐subtype‐specific agonist A61603 resulted in decreased cellular injury in a model of RV failure. The α1A‐subtype is a potential therapeutic target to treat RV failure.Support or Funding InformationSupported by Department of Veterans Affairs Merit Review Awards I01BX000740 (AJB), I01BX000593 (DHL), National Heart, Lung and Blood Institute Grant HL31113 (PCS) and an American Heart Association Grant‐in‐Aid (AJB).

A61603 Treatment Reduced Markers of Cell Injury in Bleomycin‐Induced RV Failure

Non‐failing
Bleomycin
Bleomycin +A61603

Serum Tnl (ng/ml)
5.6 ± 0.8
11.7 ± 0.6***
6.7 ± 0.7

Fmax (nN/mm2)
88 ± 3
64 ± 2***
79 ± 2

FL‐MMP‐2
1
9.8 ± 1.8*
3.9 ± 0.8

NTT‐MMP‐2
1
6.2 ± 1*
2.2 ± 1

Lung wt. /body wt. (mg/g)
7.2 ± 0.2
13 ± 0.3***
12.9 ± 0.4***

Significant differences compared to non‐failing:
P < 0.001;
P < 0.05.