bluuebunny/crossref_metadata_2025_split huggingface dataset:
Administration of Metformin During Early Reperfusion Decreases Cardiac Injury Through Inhibition of MPTP Opening
Authors: Lesnefsky Edward , Thompson Jeremy , Hu Ying , Chen Qun 
Published: November 2023

BACKGROUNDIschemia damages the electron transport chain (ETC), including at complex I. The transient, reversible blockade of complex I during early reperfusion decreases cardiac injury. Our studies in isolated mitochondria showed that high dose Metformin (MET) partially inhibits complex I in mitochondria that were damaged by ischemia. In contrast to previous chronic pretreatment studies, we asked if partial blockade of complex I only at the onset of reperfusion using high dose MET (2 mM), without pretreatment, would decrease cardiac injury. Opening of the mitochondrial permeability transition pore (MPTP) is a key effector of ETC‐mediated injury during reperfusion.METHODSBuffer‐perfused mouse hearts (C57BL/6) were subjected to 25 min ischemia and 30 min (mitochondrial isolation) or 60 min (infarct size) reperfusion with or without MET (2 mM) treatment for the first 5 min. of reperfusion only. Infarct size was used to evaluate myocardial injury. Opening of MPTP was evaluated by calcium retention capacity (CRC, nmol Ca2+/mg) in isolated mitochondria. Oxidative phosphorylation (OXPHOS) was measured.RESULTSHigh dose MET treatment at reperfusion decreased infarct size and improved contractile function compared to untreated hearts. MET decreased susceptibility to MPTP opening (improved CRC). OXPHOS rate was not improved, since much of the damage occurs during ischemia, before MET treatment during reperfusion. Thus, MET treatment decreases MPTP opening during reperfusion.CONCLUSIONAdministration of MET only during reperfusion protects hearts during ischemia‐reperfusion by partial blockade of complex I with decreased MPTP opening. Regional treatment of myocardium with high dose MET in the cardiac cath lab at the time of stent deployment for acute myocardial infarction is a clinically translatable approach to cardiac protection via modulation of the ischemia‐damaged ETC during early reperfusion.Support or Funding InformationThis work was supported by the Office of Research and Development, Medical Research Service, Department of Veterans Affairs, a CCTR grant from Virginia Commonwealth University, a Scientist Development Grant from the American Heart Association and the Pauley Heart Center of Virginia Commonwealth University.

Isolated hearts
Infarct size
LVDP
LVEDP

IR
37±4
7±1
47±4

MET + IR
15±3*
18±8*
38±2*

Isolated mito
OXPHOS (nAO/min/mg)
CRC

substrates
Glu + Mal
Succ + Rot

TC (n=5)
403±39
530±34
723±37

IR (n=6)
254±30†
396±44†
350±12†

MET+IR (n=G)
216±25†
367±18†
467±22*†

Mean ± SEM; LVDP‐developed pressure mmHg; LVEDP‐end of diastolic pressure; Complex I substrates are glutamate (Glu) + malate (Mal); complex II substrates are succinate (Succ) + rotenone (ROT);
p<0.05 vs. ischemia‐reperfusion (IR);
p<0.05 vs. TC (time control).
Lymphatic Endothelial Cell Response to X‐Ray Irradiation
Authors: Narayanan Anand , Ford John , Zawieja David 
Published: November 2023

INTRODUCTIONThe lymphatics play a key role in the redistribution of interstitial fluids, cytokines, and immune cells via lymph formation. Severe impairment in lymphatic function causes swelling and inflammation, diagnosed as lymphedema. Secondary lymphedema is a known side effect cancer patients experience after radiation therapy; however, the pathogenesis is unknown. Furthermore astronauts develop edema while in space, being exposed to chronic, low‐dose, high LET background radiation. The lymphatics response radiation has not been extensively investigated. This is one of the first investigations characterizing lymphatic endothelium responses to radiation via viability and cell morphological measures.METHODSPrimary, rat mesenteric lymphatic endothelial cells were exposed to a broad range of X‐ray (250 kVp, ~0.75 Gy/min) doses: 0, 0.5, 1, 1.5, 2, 4, 16 Gy, and travel sham. Cell viability was analyzed by XTT viability kit between 6–268 hours post‐irradiation at multiple time points. 24 and 72‐hours post‐irradiation, immunofluorescence was performed for β‐catenin, F‐actin, VE‐cadherin, DRAQ7, and measured by confocal microscopy (20× + 63× average z‐stack projections, 0.5 μm slices). No measurable differences were seen between travel sham and 0 Gy; therefore, statistical comparisons of treatment groups were made with 0 Gy group by 1‐way ANOVA and nonparametric Wilcoxon test (p<0.05).RESULTSCell viability dropped in > 1 Gy groups at day 3, but became comparable to 0 Gy values after day 7. Cell morphometry showed radiation sensitivity at all doses. Notably there was a loss of cell‐to‐cell adhesion with irradiated cells increasing in surface area coverage, marked reduction in nuclei per equivalent field of view, and increased cellular roundness. This was coupled with decreased β‐catenin & VE‐cadherin intensity and altered F‐actin anisotropy leading to a loss of intercellular contact.CONCLUSIONSLymphatics show radiation sensitivity in the context of these cell culture experiments. Our results may have functional implications of lymphatics in tissue, with potential endothelial barrier dysfunction leading to leakage and edema. These preliminary experiments will build the framework for future investigations towards clinical and space‐flight relevant lymphatic radiation exposure response.Support or Funding InformationAN is supported by the NASA‐National Space Biomedical Research Institute Predoctoral Fellowship through NCC 9–58.
The Ca2+‐activated Cl− channel TMEM16A(ANO1) modulates, but is not required for, pacemaking in mouse lymphatic vessels
Authors: Gui Peichun , Zawieja Scott , Li Min , Bulley Simon , Jaggar Jonathan , Rock Jason , Davis Michael 
Published: November 2023

An unidentified electrical pacemaker within the lymphatic vessel wall initiates the spontaneous contractions of lymphatic muscle (LM) required for normal lymph transport. The current hypothesis for pacemaking is that intracellular Ca2+ puffs within LM activate a Ca2+‐activated‐Cl− channel (CACC), initiating small depolarizations (STDs) that summate to trigger action potential (APs). The best candidate for the CACC is TMEM16A (ANO1), a channel implicated in pressure‐mediated constriction of vascular smooth muscle. We explored its role in the pacemaking of isolated, pressurized lymphatic vessels from mice, rats and humans. Contractions were always preceded by APs, which were similar in shape among all three species, pointing to a common ionic mechanism. AP firing was preceded not by STDs but by slow, constant diastolic depolarization. Ca2+ puffs/waves occurred spontaneously in many LM cells, but were not synchronized between cells or correlated with contractions. Ca2+ entry following the AP spike was mediated by L‐ and T‐type Ca2+ channels (VGCCs), generating a ~synchronized, global Ca2+ flash over the entire vessel. SERCA inhibitors abolished puffs, but not flashes or pacemaking, whereas nifedipine abolished flashes and pacemaking. TMEM16AGFP mice expressed GFP in every LM cell, as confirmed by PCR and Western blotting. Whole cell recordings from mouse LM cells revealed an outwardly‐rectifying Ca2+‐activated current, with a reversal potential around zero in symmetric [Cl−] solutions that shifted with changes in the Cl− equilibrium potential. Both broad‐spectrum (niflumic acid, DIDS) and “selective” (T16A‐01) CACC inhibitors were of limited value as they inhibited VGCCs at concentrations lower than those required to block TMEM16A. We therefore used an inducible tissue‐specific mouse model to delete TMEM16A from LM. SMMHC‐CreERt2;Rosa26mTmG mice were bred to determine the efficiency of Cre expression in LM, which was >95% in inguinal‐axillary lymphatics and ~99% in popliteal lymphatics. LM cells from SMMHC‐CreERt2;TMEM16Afl/fl mice showed significantly reduced levels of whole‐cell Cl− current compared to TMEM16Afl/fl controls. Spontaneous contractions persisted in pressurized lymphatics from SMMHC‐CreERt2; TMEM16Afl/fl mice, albeit at a significantly reduced frequency, and frequency did not increase normally with pressure elevation. These findings suggest that pacemaking is controlled by the interaction of several LM plasma membrane ionic currents rather than an intracellular Ca2+ event, but that TMEM16A contributes to a baseline excitatory current.Support or Funding InformationNIH R01 HL‐122578
microRNA‐204, SIRTUIN1, and Caveolin‐1 regulate vascular endoplasmic reticulum stress and endothelium‐dependent vasorelaxation
Authors: Kassan Modar , Vikram Ajit , Li Qiuxia , Kim Young‐Rae , Kumar Santosh , Jacobs Julia , Irani kaikobad 
Published: November 2023

BackgroundEndoplasmic reticulum (ER) stress leads to vascular endothelial dysfunction in disease states such as obesity, diabetes and hypertension. The role of microRNAs in vascular ER stress is not fully understood. Here we examined the role of vascular microRNA‐204 (miR‐204) in inducing endothelial ER stress and dysfunction by governing the expression of the SIRTUIN1 (SIRT1) lysine deacetylase and the Caveolin‐1 (Cav1).Methods & resultsmiR‐204 mimic decreased expression of SIRT1 and Cav1, and promoted ER stress in endothelial cells. Tunicamycin induced endothelial ER stress was also mediated by miR‐204. Moreover, knockdown of SIRT1 induced ER stress and reduced Cav1 in endothelial cells, both of which were rescued by a miR‐204 antagomir. Tunicamycin‐induced ER stress upregulated miR‐204, and downregulated SIRT1 and Cav1, in endothelial cells. Similarly and in endothelium of aortas and mesenteric arteries of mice. Antagonism of miR‐204, or SIRT1 overexpression, rescued endothelial cells from tunicamycin‐induced ER stress. Similarly, antagonism of miR‐204 in vivo with anti‐miR‐204 mitigated tunicamycin‐induced vascular ER stress, decline in vascular SIRT1 and Cav1, and impairment of endothelium‐dependent vasorelaxation. Moreover, tunicamycin‐induced vascular ER stress and endothelial dysfunction were exacerbated in mice with conditional deletion of endothelial SIRT1. Additionally, overexpressing Cav1 ex‐vivo, with adenovirus, in tunicamycin‐induced vascular ER stress or in mice with conditional deletion of endothelial SIRT1, reduced ER stress markers and miR‐204 in endothelial cells and was associated with an improvement in vascular endothelial dependent relaxation. Finally, Vascular miR‐204 was upregulated with high‐fat diet feeding, anti‐miR‐204 prevented vascular ER stress stimulated by high‐fat diet feeding.ConclusionsThese findings show an important role for miR‐204 as a mediator of vascular ER stress, and ER stress‐induced endothelial dysfunction, via downregulation of endothelial SIRT1 and cav1.Support or Funding InformationT32‐ Institutional Training Grant (HL007121)
Macrophages Drive Microvascular Dysfunction in Obesity by Depleting Vessel Hydrogen Sulfide
Authors: Candela Joseph John , White Carl 
Published: November 2023

Reduction in endogenous hydrogen sulfide (H2S) has emerged as a contributor to cardiovascular diseases. Its role in obesity‐induced microvasculature dysfunction is not known. Obesity is associated with chronic inflammation and recruitment of macrophages to the Perivascular Adipose Tissue (PVAT). This study was designed to test the hypothesis that vasorelaxation of the microvasculature is impaired in a diet‐induced mouse model of obesity via macrophages impinging on H2S in the microvasculature. Mesenteric arterioles were isolated from lean and obese mice and mounted in a pressure myography chamber. Vascular function was assessed using phenylephrine and acetylcholine. Vessels were loaded with the H2S indicator SF7‐AM and smooth muscle and endothelial layers imaged. The phenotype of macrophages was assessed using flow cytometry. Macrophages from obese mice took on an M1 phenotype compared to lean controls. Arterioles from obese mice showed lower concentrations of H2S compared to lean mice. Vasorelaxation in response to acetylcholine was impaired in arterioles from obese mice compared to lean mice which were reversed with exogenous H2S. Co‐culturing macrophages from obese mice with arterioles from lean or obese mice resulted in decreased endogenous hydrogen sulfide levels in the arterioles compared to when they were cultured with macrophages from lean controls. Arterioles from lean or obese mice showed impaired vasorelaxation when cultured with macrophages from obese mice compared to when they were cultured with macrophages from lean mice. These data supports a model in which H2S biosynthesis is compromised in the obese microvasculature via crosstalk with macrophages which results in impaired vessel function.Support or Funding InformationSupported by the American Heart Association and a Chicago Medical School/Advocate Lutheran General Hospital Translational Research Pilot Grant.
Changes in miRNA expression patterns and vascular aging phenotypes in mice with developmental liver‐specific knockdown of IGF‐1
Authors: Tarantini Stefano , Giles Cory B , Wren Jonathan D , Ashpole Nicole M , Valcarcel‐Ares Marta Noa , Tucsek Zsuzsanna , Sonntag William E , Csiszar Anna , Ungvari Zoltan 
Published: November 2023

The endocrine changes that occur during development are highly conserved across mammalian species and include dramatic increases in the anabolic hormone IGF‐1 during adolescence. There is increasing experimental and clinical evidence that alterations in IGF‐1 levels during development regulate multiple aspects of the aging process and affect the incidence of multiple age‐related diseases, including cardiovascular and cerebrovascular diseases. The present study was designed to characterize the effect of developmental IGF‐1 deficiency on the vascular aging phenotype. To achieve that goal early‐onset, isolated endocrine IGF‐1 deficiency was induced mice by developmental knockdown of IGF‐1 specifically in the liver using Cre‐lox technology (Igf1f/f mice crossed with mice expressing albumin‐driven Cre recombinase). The animals were studied at an age representing ~75% of maximal lifespan potential, which corresponds to the biological age of a ~67 year old human. To assess vascular health endothelium‐dependent vasorelaxation and vascular ROS production were tested. Due to the emergence of miRNAs as important regulators of vascular aging phenotype, miRNA expression profile in the aorta of mice with developmental IGF‐1 deficiency was also tested. We found that aging was associated with endothelial dysfunction, which was unaffected by developmental IGF‐1 deficiency. We identified 19 miRNAs that were differentially expressed in the aortas of aged mice and 11 miRNAs that were differentially expressed miRNAs in aortas of mice with developmental IGF‐1 deficiency. GO terms enriched among predicted targets for miRNAs differentially expressed with age in the aorta include cytokine production, chromatin silencing, intracellular protein transport and regulation of apoptotic cell death. GO terms enriched among predicted targets for miRNAs differentially expressed with developmental IGF‐1 deficiency in the aorta include regulation of apoptotic cell death, blood vessel remodeling and intracellular protein transport. Collectively, developmental IGF‐1 deficiency is associated with a vascular miRNA expression profile later in life that likely plays a role in development of age‐related vascular pathologies.Support or Funding InformationThis work was supported by grants from the American Heart Association and the National Institute on Aging
Neuromodulation of Cranial Nerves for Migraine and Trigeminal Neuropathy Pain: Cardiac Effects
Authors: White Carter R. , Snodgrass Danielle , Yazdizadeh Maryam , Yan‐Go Frisca , Jen Joanna , Harper Rebecca K. , Sauerland Eberhardt K. , Harper Ronald M. 
Published: November 2023

Neuromodulation of afferent cranial nerve activity is useful for alleviating migraine and trigeminal pain, which is often poorly managed by pharmacologic interventions. Synchronous stimulation of trigeminal, vagal, glossopharyngeal and cervical nerve afferents shows promise for such intervention, but potential effects on the cardiovascular system must be considered, since several of the cranial nerves exert significant effects on heart rate and blood pressure. The objective was to determine changes in heart rate (HR), HR variability, and blood pressure at two stimulation amplitude levels to cranial nerves. Fourteen subjects with confirmed migraine or trigeminal neuropathy pain were fitted with vibrating devices placed in the ear canals bilaterally. Heart rate (beats/min), inter‐beat intervals (RR, msec), beat‐by‐beat systolic and diastolic blood pressures (mm Hg) were measured continuously during baseline, and during low and high amplitude, and post stimulation periods. Mean HR declined during low and high stimulation; baseline, low, high, and post‐session were 76, 73, 72, 74 bpm respectively, p < .001 (Single‐Factor Repeated Measures ANOVA), with lengthening of mean RR intervals (802, 829, 839, 821 msec, respectively). HR and RR intervals recovered during the post stimulation period to pre‐session values. Mean systolic and diastolic blood pressure declined with stimulation (mean systolic: 130, 124, 125, and 130 mm Hg, respectively; mean diastolic: 79, 77, 77, and 79 mm Hg, respectively), and recovered post‐stimulation. HR variability patterns changed from pronounced baseline variation from respiratory and slower variation influences to reduced slower, but increased respiratory‐related variation, representing a shift to parasympathetic influences during stimulation; these values recovered post‐stimulation. No instances of potentially dangerous bradycardia or tachycardia, or extreme changes in blood pressure appeared. We conclude that HR, HR variability, and blood pressure change during stimulation, and move toward values considered “protective.”Support or Funding InformationPrivate Funding was used for this project.
Hemodynamic effects of Enalapril and B‐type natriuretic peptide on the progression of pacing induced cardiac myopathy in conscious dogs
Authors: Qanud Khaled , Shnayderman Nadine , Ochoa Manuel , Xu Xiaobin , Hintze Thomas 
Published: November 2023

PurposeEnalapril and B‐type natriuretic peptide (BNP) are used in cardiovascular clinical practice as a common anti‐hypertensive drugs and a diagnostic marker of heart failure (HF). BNP is secreted from ventricular cardiomyocytes in response to high cardiac filling pressures and has anti‐hypertensive actions by stimulating natriuresis and diuresis. Typically, BNP is elevated in HF but studies suggest that a resistance to endogenous BNP causes this. Thus BNP could be potentially therapeutic as an exogenous source. Few studies have elucidated the changes in hemodynamics and echocardiographic parameters and the outcome on the pulmonary component during HF. Here we tested whether the above mentioned parameters could be favorably affected by Enalapril, BNP and the possible combined treatment resulting in slowing the progression or improving the tolerance to HF.MethodsTwelve chronically instrumented dogs underwent left ventricular pacing at 210 beats/min for 3 weeks and at 240 beat/min thereafter. Starting at day 10 of pacing, the dogs were randomized into three groups to receive either Enalapril (1 mg/kg) orally, BNP (5–25 mg/kg) by sc injection, or placebo. The transitions from compensated dysfunction to HF occurred between the 3rd and 4th week of pacing, with end‐stage HF occurring at 28±1 days.ResultsWe found that dP/dtmax, LVEDP and arterial BP remained unchanged between the control and treated groups. However, Arterial PO2 was better preserved in the Enalapril group compared to the placebo group. Arterial PO2 typically falls during the decompensated stages of HF and is indicative of pulmonary edema. By week 4, arterial PO2 was significantly higher in the Enalapril group (88±2.8 mmHg) compared to the placebo group (78±3.0 mmHg, p<0.05). Echocardiography showed that EF was significantly maintained in the Enalapril group compared to the BNP (weeks 1, 3) and placebo (weeks 2, 3) groups indicating that, although small, the EF may be better maintained. At week 3, EF was 37±2.5% and 39±1.6% for the BNP and placebo groups, respectively, whereas the Enalapril group had an EF of 45±1.6% (p<0.05). In addition, end systolic diameters were significantly decreased with Enalapril compared to the placebo (weeks 2–4). No significant hemodynamic or echocardiographic changes were detected in comparison of compensated dysfunction and end stage heart failure of the groups.ConclusionOur data suggests that Enalapril and BNP treated dogs maintained a preserved cardiac systolic function and hemodynamic tolerance during end stage HF, as reflected by clinical parameters and blood values (PO2). Although the data did not reflect significant changes between BNP and placebo, it did not worsen the progression of HF and could be considered safe.
Medical Device Materials and Blood Pressure Alterations in Mice
Authors: Swiercz Adam , Sherman Meredith , Muselimyan Narine , Swift Luther , Marvar Paul , Posnack Nikki Gillum 
Published: November 2023

Di‐2‐ethylhexyl phthalate (DEHP) is a plasticizer that is used to impart flexibility to polyvinyl chloride products. Patients have an increased exposure to phthalates through contact with DEHP‐containing medical devices, including: storage bags containing blood, plasma, intravenous fluids, total parenteral nutrition, tubing associated with their administration, nasogastric tubes, enteral feeding tubes, catheters, extracorporeal membrane oxygenation (ECMO) circuits, hemodialysis tubing, respiratory masks and endotracheal tubes. Human health concerns pertaining to DEHP exposure are linked to its endocrine‐disrupting properties. Accordingly, increased exposure has been associated with cancer, metabolic disturbances, reproductive and neurological disorders, and cardiovascular disease. As an example, epidemiological studies have shown a link between DEHP exposure and elevated systolic blood pressure in adolescents. Despite bans and restrictions on the use of DEHP‐containing medical devices in other countries, there is currently no mandate from the Food & Drug Administration for the use of DEHP‐free devices and storage containers. The objective of this study was to quantify the impact of in vivo DEHP exposure on cardiovascular function; thereby, providing additional information for regulatory decisions by the scientific, medical and regulatory community. Healthy C57BL/6 male mice were implanted with radiotelemetry transmitters; briefly, the transmitter catheter was placed in the carotid artery and biopotential leads were routed subcutaneously to collect electrocardiogram (ECG) signals. After surgical recovery, pre‐exposure data was collected, and thereafter, animals were exposed to 0.2 mg/g DEHP or control diet for 4‐weeks. We observed a significant increase in systolic pressure in DEHP‐treated (145 ± 3 mmHg) vs control animals (136 ± 1 mmHg). We also detected an increase in diastolic and mean arterial pressure in DEHP‐treated (119 ± 5 and 132 ± 3 mmHg, respectively) vs control animals (107 ± 2 and 121 ± 2 mmHg). Our previous reports have shown that DEHP diminishes cardiac contractility, which suggests that these effects on blood pressure are likely attributed to alterations in parasympathetic tone and/or an increase in vascular resistance.Support or Funding InformationThis work was supported by the National Institutes of Health (K99ES023477) and the Clinical and Translational Institute at Children's National (UL1TR000075 and KL2TR000076, from the NIH National Center for Advancing Translational Sciences).