bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gamma Linoleic Acid and Trans Linoleic Acid Effects on Atherogenic Dieted Rabbit Tissue Sensitivity to Insulin
Authors: Beard Elizabeth Letitia , Swafford Albert Nicholas 
Published: November 2023

The effects of adding 5% Primrose oil‐(PO) [ containing 9% Gamma Linolenic Acid (GLA)] and/or 5% Soy Oil (SO) [containing 35% Trans Linoleic acid (TLA)] ‐to the Atherogenic Diet (AD) fed to rabbits for a 30 day interval, were studied regarding their ability to alter their tissue sensitivity to insulin. New Zealand strain male rabbits were divided into diet groups with four animals/group. Group I‐(AD Control ) rabbits were maintained on AD containing 92% Purina Rabbit Chow, 6% Corn Oil and 2% Cholesterol. Group II (AD+SO) animals were fed AD + 5% SO, Group III (AD+PO) animals received AD+ 5%.PO, and Group IV (AD+SO+PO), rabbits were fed AD + 2.5% PO and 2.5% SO. Blood platelet samples were isolated from the blood plasma samples drawn from each group. These were incubated in media with exogenous insulin and glucose then washed, homogenized and assayed for their glucose content. The mean glucose values determined in the platelet homogenates were: I. (AD Control ) : 0.41mg/dl, II. (AD+SO ): 0.51mg/dl, III. (AD+ PO): 1.09 mg/dl and IV. (AD + {2.5%PO + 2.5% SO): 0.96 mg/dl. The mean cholesterol levels found in the blood plasma samples of these groups were: I. (AD Controls): 72.6mg/dl. II. (AD+ SO): 73.5 mg ‘dl, III. (AD+PO): 52mg/dl, and in IV. (AD+ (2.5%SO and 2.5%PO), the level rose to 59 mg/dl. Blood platelet mean cholesterol levels were : I. (AD Control) :75.6mg/dl, II. (AD +SO): 56.3mg/dl, III. (AD+PO) values fell to 33.3 mg/dl, and IV. (AD+2.5%PO+2.5%SO): 33.9mg/dl. Rabbits fed AD with PO/GLA supplement, were found to have reduced plaque development in their aortae at autopsy compared to the those lacking GLA supplement in the diet. GLA supplementation to an atherogenic diet appears in these findings to work against the development of hypercholesterolemia and decresased sensitivity to insulin that develops in rabbits with prolonged feeding of an atherogenic diet containing 2% cholesterol as well as atherogenic plaque build up in the aorta..Support or Funding InformationAmerican Heart Association‐ Louisiana
Sigma Receptor Agonism by Afobazole Attenuates Lymphatic Pumping in Juvenile Rat Mesenteric Collecting Vessels
Authors: Trujillo Andrea Nichole , Adderley Shaquria P , Katnik Christopher P , Cuevas Javier , Breslin Jerome W 
Published: November 2023

The mechanisms that govern tone and phasic contractions of collecting lymphatics are known to involve transient increases in intracellular free Ca2+ but are still poorly understood. The role of sigma (σ) receptors, chaperone proteins recently identified to modulate intracellular free Ca2+ has not been previously explored. We studied mesenteric collecting lymphatics isolated from 5–9 week old male Sprague Dawley rats, investigating whether: 1) sigma receptors, are expressed in lymphatic collecting vessels; and 2) Afobazole modulates tone and pumping. Lymphatics were mounted onto resistance‐matched glass micropipettes, in a 37°C albumin physiological salt solution (APSS) bath with 1–2 cm H2O luminal pressure. Concentrations of 50, 100 and 150 μM Afobazole were assessed. Video recordings were used to obtain contraction frequency (CF), end diastolic diameter (EDD), end systolic diameter (ESD), phasic contraction amplitude (AMP), tone, and ejection fraction (EF). Ca2+‐free APSS was used to obtain the maximal passive diameter (MaxD) used to normalize EDD, ESD and AMP. Expression of the sigma 1 (σ1) receptor in lymphatics was verified by q‐PCR and western blot. Afobazole (50–150 μM) decreased CF, AMP/MaxD, tone and EF, and increased ESD/MaxD compared to baseline. A 15‐min pre‐treatment with either BD 1047 dihydrobromide or BD 1063 dihydrochloride, both σ1 receptor antagonists, blocked the effects produced by 50 and 100 μM Afobazole. Similar pre‐treatment with SM‐21, a specific antagonist of the σ2 receptor, did not block the responses to Afobazole (50–100 μM). Lastly, using multi‐photon laser‐scanning microscopy, the σ1 receptor was detected in lymphatic collecting vessels, closely associated with the endothelium. This study shows, for the first time, that agonists of the σ1 receptor can negatively modulate juvenile mesenteric lymphatic vessel contractile function.Support or Funding InformationSupported by NIH grant L40HL097863
Impact of Dynamic Transmural Pressure on Lymph Propulsion in Lymphatic Vessels
Authors: Jamalian Samira , Davis Michael J , Zawieja David C , Moore James E 
Published: November 2023

Transmural pressure is an important determinant of pumping in collecting lymphatic vessels. Here we studied the impact of dynamic transmural pressure in lymphatic vessels using our physiology‐based computational model [1]. In parallel, we conducted in vitro studies in isolated lymphatic vessels from rat mesentery to examine the effect of dynamic transmural pressure. Vessel segments containing multiple valves were isolated, cannulated, and pressurized at varying levels of inlet and outlet pressures (Pin = Pout, zero transaxial pressure difference). Dynamic pressure waves at different physiologic frequencies (0 – 0.5 Hz) and amplitudes (0 – Pin) were introduced at the inlet and outlet reservoirs. Intraluminal pressure (measured with a servo‐null system) and inner diameter were recorded throughout the experiment. At all pressure amplitudes and frequencies (both higher and lower than normal contraction frequency of the vessel), the dynamic pressure wave was superimposed on the physiologic contraction of the vessel and was detectable in both the intraluminal pressure and diameter traces. The results of our computational model demonstrated that dynamic transmural pressure increased the flow rate at low baseline transmural pressures. Under these circumstances increasing the amplitude and/or frequency of oscillations further facilitated the pumping. Additionally, our computational model enables us to control the transmural pressure by varying external pressure (independent of inlet and outlet pressures). This allows us to study conditions with non‐zero transaxial pressure differences. For example, for an adverse pressure difference of 3 cmH2O and average transmural pressure of 3 cmH2O, average flow rate increased 10% when transmural pressure oscillated with an amplitude of 1 cmH2O; doubling the contraction frequency resulted in a further 15% higher flow rate. These results suggest that dynamic transmural pressure can play an important role in maintaining lymph propulsion in areas of weaker intrinsic pumping activity.Support or Funding InformationGrant support: NIH R01 HL094269, U01 HL123420 (JEM), NIH R01 HL‐120867 (MJD). JEM wishes to acknowledge the support of The Royal Society, The Royal Academy of Engineering, and The Sir Leon Bagrit Trust.
A Novel Mouse Model of Inducible Lymphangiogenesis Through Controlled Local Expression of VEGF‐D
Authors: Rutkowski Joseph M 
Published: November 2023

Lymphatic vessels are an integral part of the body's circulatory system. Lymphatic circulation modulates tissue fluid balance and inflammation and provides a conduit for endocrine and lipid transport as well as a pathway for cancer cell metastasis. The growth of new lymphatic vessels in the adult – lymphangiogenesis – is predominantly mediated through vascular endothelial growth factor receptor‐3 (VEGFR‐3) signaling upon binding of its ligands VEGF‐C and VEGF‐D. Lymphangiogenesis may be therapeutic in conditions of lymphatic deficiency (e.g., post‐lymphadenectomy), but may also be a negative driver of lymphatic proliferative pathologies such as GLA, Gorham‐Stout disease, and lymphangioleiomyomatosis. While human VEGF‐C and –D both can bind VEGFR‐2 as well, mouse VEGF‐D only binds VEGFR‐3. We took advantage of this unique interaction and generated mice capable of inducible, tissue‐specific expression of VEGF‐D under a tightly‐controlled tetracycline response element (TRE) promoter. This limits VEGF‐D expression to be cell‐specific and only upon doxycycline (administered in the water or chow) activation, thus providing a novel model of local lymphangiogenesis. We confirmed tight, dose‐responsive VEGF‐D expression with the TRE‐VEGF‐D mouse crossed to mice with tissue‐specific promoters for the lung (CCSP‐rtTA), kidney (KSP‐rtTA), and adipose tissue (adiponectin‐rtTA). Induction of VEGF‐D expression in these tissues resulted in marked lymphatic endothelial cell massive lymphatic vessel hyperplasia and hypertrophy. The inducible TRE‐VEGF‐D mouse thus provides a novel murine platform to study the adult mechanisms and therapies of an array of disease‐ and tissue‐specific models of lymphangiogenesis.Support or Funding InformationAHA 12SDG12050287
Morphometric Analyses of Longitudinal and Circular Smooth Muscle and Lacteals of the Small Intestine of Zucker Lean and Obese Rats
Authors: Burgess Andrea R , Trujillo Andrea N , Barter Micaela , Breslin Jerome W 
Published: November 2023

Lymph lacteals are the entry point of absorbed fats and cholesterol in the villi of the small intestine. In a recent study, lacteals and the leakiness of the submucosal lympahtic network was implicated as a source for adult‐onset obesity (Harvey et al. 2005). The purpose of this study was to determine what structural differences may exist in the lacteals, submucosa, and other layers of the ileum between lean and obese Zucker rats using histochemistry (H&E) and immunofluorescence microscopy. We hypothesized that due to increased food intake and levels of digested fats in the obese Zucker rat, the lacteals and the smooth muscle layers of the ileum will modify from their normal appearance to accommodate the increased intake of fats and volume of food respectively. Ileum from lean and obese Zucker rats was harvested, fixed in buffered formalin overnight, processed and embedded in paraffin. Cross sections (2–3 μm) of the ileum were mounted on slides and stained with H&E to measure longitudinal and circular smooth muscle layer thickness. Similar sections were incubated with a LYVE‐1 antibody to identify lymphatic endothelial cells of the lacteals and a smooth muscle actin (SMA) antibody to label smooth muscle cells extending into the villi. Layers of longitudinal and circular smooth muscle, identified in the ileum with H&E staining, were significantly thicker in obese Zucker rats compared to lean rats. Preliminary immunolabeling with LYVE‐1 identified positive endothelial cells in crypts of the sub mucosae and SMA‐positive smooth muscle cells that extended into the villi (lamina propria). SMA was also detected in the circular and longitudinal muscle layers and the muscularis muscosae as predicted. Histological data obtained from the ileum support the hypothesis that increased food intake increases intestinal smooth muscle layer thickness in obese Zucker rats.Support or Funding InformationThis work was supported by an APS/NHLBI STRIDE Undergraduate Summer Research Fellowship (NIH R25HL115473) and NIH grant L40HL097863.
IGF‐1 deficiency exacerbates hypertension‐induced cerebromicrovascular rarefaction in mice: implications for cognitive decline
Authors: Tarantini Stefano , Giles Cory , Toth Peter , Ashpole Nicole M , Tucsek Zsuzsanna , Valcarcel‐Ares Marta Noa , Gautam Tripti , Sonntag William E , Wren Jonathan D , Csiszar Anna , Ungvari Zoltan 
Published: November 2023

Aging is associated with marked deficiency in circulating insulin‐like growth factor (IGF‐1), which has been shown to contribute to age‐related cognitive decline. The mechanisms by which IGF‐1 deficiency impairs brain function are multifaceted and likely involve impairment of cerebral microcirculation. Accordingly, previously we have shown that IGF‐1 deficiency impairs cerebromicrovascular endothelial function, neurovascular coupling and adaptation of myogenic autoregulatory mechanisms to hypertension, contributing to blood‐brain barrier disruption and neuroinflammation. The present study was designed to characterize the effects of IGF‐1 deficiency on microvascular density in the brain and its pathogenic role in hypertension‐induced microvascular injury. Circulating IGF‐1 deficiency was induced in mice by AAV‐mediated knockdown of IGF‐1 in the liver (Igf1f/f+TBG‐Cre‐AAV8). Hypertension was induced by chronic infusion of angiotensin‐II. We found that circulating IGF‐1 deficiency is associated with decreased microvascular density and exacerbates hypertension‐induced microvascular rarefaction in the cortex and the hippocampus. Hippocampal microvascular rarefaction positively correlated with impairment of hippocampal‐dependent cognitive function. To elucidate the mechanisms underlying the synergistic effects of hypertension and IGF‐1 deficiency on microvascular density hippocampal mRNA expression of genes involved in regulation of angiogenesis and microvascular regression was assessed using a targeted qPCR array. Both hypertension and IGF‐1 deficiency appear to decrease the expression of a number of genes involved in the maintenance of the structural integrity of the cerebral microcirculation (e.g. Vegfb, Pdgfrb), while increasing the expression of genes promoting endothelial apoptosis and/or microvascular regression (e.g. Tnfa, Angpt2). Gene set enrichment analysis scores calculated for positive and negative regulators of angiogenesis suggest that interaction of hypertension in IGF‐1 deficiency results in an exacerbated negative angiogenesis signature. Collectively, IGF‐1 deficiency promotes cerebromicrovascular rarefaction and exacerbates hypertension‐induced structural damage to the cerebral microcirculation, which likely contribute to the deleterious effects of age‐related IGF‐1 deficiency on higher brain function in the elderly.Support or Funding InformationThis work was supported by grants from the American Heart Association and the National Institute on Aging
Cutaneous Thermal Injury Increases Vascular Permeability of Rat Mesenteric Venules by a Reactive Oxidant‐Dependent Mechanism
Authors: Pfitzinger Duke M. , Howard James M. , Moncure Michael , Wood John 
Published: November 2023

BackgroundFollowing major burns, edema develops in systemic organs and contributes to the development of remote organ dysfunction. The underlying mechanisms responsible for microvascular inflammation in this setting are not yet fully known. The purpose of our study was to determine if thermal injury to the skin of rats would increase vascular permeability in the mesenteric microcirculation, and if the mechanism involved generation of reactive oxidants.MethodsIntravital microscopy was used to examine mesenteric venules of anesthetized rats. FITC‐albumin was used to determine a vascular permeability index (VPI) based on the ratio of extravascular to intravascular fluorescence. Thermal injury was induced by exposing skin of animals to steam for 1 min (~40% of body surface area). Control animals were not exposed to steam. Vehicle or the antioxidant lipoic acid (2 mg/kg bolus, 0.5 mg/kg/h) was administered i.v. to animals after steam injury.ResultsVPI significantly increased after burn (0.39±0.13 at 30 min vs 0.61±0.08 at 4 h, p<0.05, n=5), but not in non‐burned animals (0.08±0.09 at 30 min vs 0.12±0.03 at 4 h, n=5). These values for VPI were significantly different at these times in burned and non‐burned animals (p<0.05). Lipoic acid significantly attenuated VPI in burn animals (0.20±0.06 at 30 min and 0.23±0.05 at 4 h, n=5) compared to vehicle‐treated burn animals (p<0.05).ConclusionsThermal injury to the skin of rats increased vascular permeability in the mesenteric microcirculation of rats. Lipoic acid attenuated this increase which supports a role for increased generation of reactive oxidants in this mechanism.Support or Funding InformationDepartment of Surgery Research Funds
Decreased Large Conduit Artery Nitric Oxide Bioavailability in Metabolic Syndrome Effects Peripheral Microvessel Reactivity
Authors: Branyan Kayla , DeVallance Evan , Lemaster Kent , Skinner Roy , Brooks Steve , Asano Shinichi , Willimas Justin , Frisbee Jefferson , Chantler Paul 
Published: November 2023

One out of every five adults in the U.S. are considered to have multiple components of Metabolic Syndrome (MetS). These components include dyslipidemia, hypertension, insulin resistance, and a chronic pro‐inflammatory state, which significantly increase the risk for poor cardiovascular outcomes. Nitric oxide (NO) bioavailability is decreased in MetS, leading to vascular dysfunction. With this decrease in vascular function, there is an increased risk of poor cardiovascular outcomes. A common animal model used to mimic MetS is the obese Zucker rat (OZR) whereas its lean counterpart is used as a healthy control. The purpose of this study was to determine the extent of impairment in NO bioavailability in large conduit arteries and compare that to the reactivity of the related microvessels, such as the gracilis arteriole. Specifically, a DAF‐FM diacetate assay was used to determine the degree of NO production in the aorta. To assess microvessel reactivity, the gracilis arteriole was isolated, hung in a pressurized microvessel myobath, and was exposed to increasing doses of acetylcholine to measure endothelial function. TEMPOL was also used to determine the role of oxidant stress in modulating reactivity via vasodilation. LZRs had a higher overall NO bioavailability as compared to OZRs (p<0.05). This was reflected in gracilis reactivity where the LZRs had increased gracilis reactivity than OZRs overall (p<0.01). With TEMPOL, percent dilation was doubled in the gracilis of OZRs (p<0.01) but this effect was not seen in the LZRs. These results suggest that oxidant stress causes vascular dysfunction and that a higher NO bioavailability correlates with better microvascular reactivity. When a membrane‐permeable radical scavenger is introduced, reactive oxygen species that are causing the oxidative stress can be decreased to improve reactivity in a MetS model.Support or Funding InformationAHANIH
A Redox Responsive MRI Contrast Agent for the Detection of Oxidative Stress in the Heart
Authors: Schwartz Dean , Yu Meng , Goldsmith Christian R , Beyers Ronald , Cattley Russell C 
Published: November 2023

The over‐production of reactive oxygen species (ROS), known as oxidative stress, has been implicated in many mechanisms of tissue injury. The exact role of ROS remains poorly understood, which has motivated efforts to develop imaging techniques capable of differentiating normal from aberrant biological redox activity. A mononuclear Mn(II) complex with the redox‐active ligand N,N′‐bis(2,5‐dihydroxybenzyl)‐N,N′‐bis(2‐pyridinylmethyl)‐1,2‐ethanediamine (H4qtp2) responsive to hydrogen peroxide was synthesized and characterized. The capability of H4qtp2 to serve as a MRI contrast agent was assessed by 3T MR T1 relaxometry. The relationship between the concentration of H4qtp2 and T1 was linear and consistent with the Mn(II)‐H4qtp2 adducts remaining intact in solution. The slope yielded a relaxivity (r1) of 5.27 mM−1 s−1. The r1 of H4qtp2 increased to 7.02 mM−1 s−1 upon the addition of 10 mM hydrogen peroxide. H4qtp2 also behaves as a strong anti‐oxidant, as evidenced by its ability to degrade superoxide and serve as a hydrogen atom donor in vitro. We next assessed the ability of this agent to detect oxidative stress in the heart. For these studies, rats were injected with the anthracycline anticancer drug, doxorubicin (DOX, 15 mg/kg i.p.). The clinical use of DOX is limited due to cumulative dose‐dependent irreversible cardiotoxicity that leads to congestive heart failure. The mechanism of toxicity is widely accepted to result from the excess generation of reactive oxygen species (ROS) and the resulting oxidative stress in cardiac myocytes. DOX treated rats displayed prolonged ECG QT intervals but no indications of oxidative‐stress induced lipid peroxidation on days 3 or 7. There was, however, an increase in the expression of a number of antioxidant genes in the heart. For cardiac MRI, rats were anesthetized with isoflurane and MRI was performed using a Siemens actively‐shielded whole body 7T MRI scanner. Dark‐blood, T1‐weighted Cine was performed to quantify cardiac function. T1‐mapping was performed with an inversion recovery Look‐Locker sequence before and after intravenous infusion of the redox‐responsive MRI agent H4qtp2 (10 mg/kg i.v.). Ejection fraction in control rats was 60.5 +/− 2.5 % and in DOX rats was 50 +/− 2.8% seven days after DOX administration. The T1 (sec) in the myocardium of control rats was similar before and after infusion of H4qtp2. The T1 (sec) decreased by 11.8% in the hearts of DOX‐treated rats whereas there was no change in the T1 in skeletal muscle in these same rats. The data suggest that H4qtp2 can be used to detect oxidative stress in the hearts of doxorubicin treated rats.Support or Funding InformationFunded in part by Auburn University Research Initiative in Cancer (AURIC).
Endothelial derived hyperpolarization in vivo in hypertensive rats
Authors: Brasen J. Christian , Stannov Søs Urup , Salomonsson Max , Sorensen Charlotte Mehlin 
Published: November 2023

Endothelial derived hyperpolarization (EDH) plays a role in regulation of vascular tone, but little is known about its role in renal arteries in vivo. Whether EDH is affected by hypertension or vice versa is also unknown. We have investigated if the magnitude of EDH in renal arteries in vivo is different between normotensive and hypertensive rats and what the difference could be due to. In this study we quantify renal EDH in vivo in normotensive Sprague Dawley (SpD) rats and spontaneous hypertensive rats (SHR). Renal blood flow is measured in sevoflurane anesthetized rats. The ACh‐induced increase in renal blood flow (RBF) is measured before and after inhibition of the nitric oxide synthase and cyclooxygenase with L‐NAME and indomethacin, respectively.Mean arterial pressure (MAP) is significantly higher in SHR (139 mmHg) compared to SpD (97 mmHg). Infusion of L‐NAME and indomethacin decreased RBF and increased MAP in both strains. We therefore used renal vascular resistance (RVR) to quantify EDH. Following infusion of L‐NAME and indomethacin RVR increased from 14 to 25 mmHg × min/ml in the SpD, whereas RVR increased from 27 to 72 mmHg × min/ml in the SHR. When L‐NAME and indomethacin were infused the decrease in RVR following infusion of ACh was greater in the SHR (from 73 to 67 mmHg × min/ml) compared to the SpD (from 21 to 18 mmHg × min/ml). In the SpD inhibition of the alpha‐1 adrenergic receptor with prazosin had no significant effect on RVR in the presence of L‐NAME and indomethacin. The magnitude of the EDH response was also not significantly different with or without prazosin. In the SHR RVR was not significantly different after prazosin infusion in the presence of L‐NAME and indomethacin. However, the effect of EDH measured as a decrease in RVR was greater in the prazosin treated animals. The vasodilator papaverine did not change EDH in SpD, but in the SHR it was reduced. Infusion of NE or AngII did not change the EDH response the SpD or SHR. These results suggest that alpha adrenoceptor activity might be responsible for the reduced EDH in SHR.