bluuebunny/crossref_metadata_2025 huggingface dataset:
Lyophilized plasma prevents endothelial leak and improves oxygenation following traumatic hemorrhage
Authors: McCully Belinda H , Dean Rondi K , Connelly Christopher R , Martin David T , Perl Vicente J Undurraga , Watson Justin , Yonge Davis , Rick Elizabeth A , Baimukanova Gyulnar , Pati Shibani , Schreiber Martin A
Published: November 2023

Lyophilized plasma (LP) reconstituted to 100% (1×LP) or 50% (2×LP) of its original volume is just as effective as fresh frozen plasma (FFP) in correcting hemodynamic instability and coagulopathy following traumatic hemorrhagic shock. Compared to transfusion with lactated Ringers (LR), FFP also prevents the endotheliopathy of trauma (EOT) following hemorrhagic shock by attenuating vascular endothelial leak, which prevents endothelial damage, edema and end organ injury. Whether LP acts similarly to FFP on the vascular endothelium in preventing EOT is not known. Therefore, we hypothesized that similar to FFP, 1×LP and 2×LP would minimize endothelial permeability and prevent pulmonary dysfunction following traumatic hemorrhage. To test this hypothesis, two experiments were performed. To test for endothelial permeability in vitro, human pulmonary endothelial cells (HPECs) suspended in growth media were treated with FFP, 1×LP or 2×LP. Increased trans‐endothelial membrane resistance (TEER) indicated decreased permeability and barrier function recovery. When HPECs were treated in 10% plasma, the rise in TEER from baseline was similar in cells treated with FFP (22%) and 2×LP (27%), and highest with 1×LP treatment (33%, p<0.05 vs FFP and 2×LP). However, when cells were treated with 2% plasma, the rise in TEER was highest in HPECs treated with 2×LP (29%), followed by FFP (22%), and 1×LP (15%). To test for pulmonary dysfunction in vivo, anesthetized female swine subjected to 30min of uncontrolled hemorrhage from Grade V liver injury were resuscitated with lactated Ringers (LR), FFP, 1×LP or 2×LP. Following conscious recovery, arterial blood gasses were measured 24hrs post‐injury. PaO2 and arterial O2 saturation were low in LR‐treated swine (n=1; PaO2:52mmHg, O2:87%), but improved with FFP (n=2, PaO2:77±1mmHg, O2:97±0%), 1xLP (n=2; PaO2:73±8mmHg, O2:97±1%) and 2×LP (n=2; PaO2:72±4mmHg, O2:96±1%). Only LR‐treated swine exhibited gross pulmonary vascular thrombosis. Take together, these data suggests that LP and FFP act similarly to prevent endothelial permeability and pulmonary dysfunction after injury. Further experiments are required to determine if LP performs as well as FFP to minimize EOT and organ damage following hemorrhagic shock.

Support or Funding Information

This work was funded by DOD US Army Grant W81XWH‐04‐1‐0114 (Schreiber)
Gender Differences in Sepsis‐Induced Nitric Oxide and EDHF Signaling Pathways in Rat Aorta
Authors: Kuntamallappanavar Guruprasad , Leo M. Dennis , Subramani Jaganathan , Mishra Santosh K
Published: November 2023

Despite recent advances in managing sepsis, it still remains a major health concern in the US. Sepsis is characterized by systemic hypotension, pulmonary hypertension and refractoriness of the vasculature to contractile factors. Nitric Oxide (NO) and Endothelium‐Dependent Hyperpolarizing Factor (EDHF) are crucial in the regulation of vascular tone. The influence of gender on endothelial function in sepsis remains unknown. Therefore, this study was aimed to investigate the influence of gender on sepsis‐induced NO and EDHF signaling pathways in rat aorta. Results indicate that NO and EDHF play a major role in sepsis‐induced endothelial dysfunction in rat aorta in a experimental model of sepsis. Sepsis was induced in rats by cecal ligation and puncture (CLP). 18h after surgery septic rats showed increase in rectal temperature, neutrophilia, pulmonary edema and an increase in plasma nitrate/nitrite levels. However, mean arterial pressure was decreased. Arterial vasoreactivity was measured using an isometric tension protocol. Phenylephrine (PE) was more potent in contracting aortic rings from female than male rats, but the amplitude of contraction was identical in both the sexes. Sepsis significantly decreased the efficacy of PE in aortas from both the sexes. Acetylcholine (ACh) elicited concentration‐dependent relaxation in endothelium intact aortas from male and female rats. Sepsis had no significant effect on the endothelium‐dependent relaxation in the female aorta, but caused significant reduction in the maximal response to ACh in male aortas. There was no evidence of EDHF activity in aortic rings from either sex. Sodium nitroprusside (SNP) was more potent in dilating aortas from male than female rats. Sepsis had no significant effect on the potency or efficacy of SNP‐induced dilation in both genders. Real time PCR was used to measure mRNA expression levels of potassium channels important in the endothelium. In conclusion, the results of present study suggest that sepsis‐induced alteration in the reactivity of aorta to vasoconstrictors or vasodilators is dependent on the gender of the animal.
Vascular Endoplasmic Reticulum Stress Does Not Contribute To Exacerbated Organ Damage And Mortality In Smooth Muscle Cell BK Channel Deficient Septic Mice
Authors: Xu Hui , Wang Youping , Fernandes Roxanne , Fink Gregory D , Galligan James J
Published: November 2023

Smooth muscle cell (SMC) BK channel deficient (BK channel β1‐subunit knockout, BK β1‐KO) mice have disrupted SMC intracellular Ca2+ homeostasis and increased sensitivity to polymicrobial sepsis‐induced organ damage and mortality. Here we evaluated the contribution of vascular endoplasmic reticulum (ER) stress to the exacerbated organ damage and mortality. At 24 hours post‐cecal ligation/puncture, the mortality was greater in BK β1‐KO vs wild‐type (WT) mice. Expression of ER stress protein indicators (immunoglobulin‐heavy‐chain‐binding protein, Bip; protein disulfied isomerase, PDI; inositol‐requiring kinase‐1α, IRE‐1α; and 94‐kilodalton glucose regulated protein, GRP94) in mesenteric arteries was similar in all septic and non‐septic control mice. Expression of C/EBP homologous protein (CHOP), a transcriptional factor of apoptosis, was undetectable in mesenteric arteries from all control and septic mice, but CHOP expression was detected in arteries from control mice treated with tunicamycin, an ER stress inducer. In saline‐resuscitated septic mice, treatment with ER stress antagonists (tauroursodeoxycholic acid and 4‐phenylbutyric acid) did not protect against the exacerbated hypothermia, organ damage and mortality in BK b1‐KO mice. 4‐phenylbutyric acid even exacerbated mortality in septic WT mice. Our data indicate that ER stress is not responsible for the worsened organ damage and mortality observed in mice with vascular BK channel deficiency.

Support or Funding Information

National Heart, Lung and Blood Institute (P01 HL070687 for H.X., J.J.G., and G.D.F.) and the American Heart Association Midwest Affiliate (11GRNT6690010 for H.X.).
Arachidonic Acid‐Induced TRPV4 Activation is Enhanced by Serine Phosphorylation in Human Coronary Artery Endothelial Cells
Authors: Cao Sheng , Nishijima Yoshinori , Zhang David X.
Published: November 2023

Recent studies indicate that the transient receptor potential (TRP) vallinoid type 4 (TRPV4), a Ca2+‐permeable cation channel expressed in vascular endothelial cells, may serve as a key signaling component transducing flow stimulus into H2O2‐mediated human coronary arteriolar dilation in disease. Furthermore, in human coronary artery endothelial cells (HCAEC), we found that arachidonic acid (AA) acts as an endogenous lipid activator of TRPV4 channels and this activation requires protein kinase A (PKA)‐mediated protein phosphorylation. This study is designed to identify the PKA phosphorylation site(s) on TRPV4 protein that is essential for the channel activation by AA in coronary endothelial cells. Compared with HCAEC overexpressing wild‐type (WT) TRPV4, AA (3 μM)‐induced Ca2+ increase was blunted in the non‐phosphorylatable S824A mutant, whereas an enhanced TRPV4 response to AA was observed in the phospho‐mimetic S824E mutant. TRPV4 activation by the pharmacological agonist GSK1016790A (1 nM) was not affected in either S824A or S824E mutant. Cell surface biotinylation assay revealed that these point mutations did not affect protein expression on the plasma membrane. Using an anti‐phosphoserine pS824 antibody, we found that forskolin (10 μM; PKA activator) enhanced S824 phosphorylation in WT TRPV4 but failed to induce phosphorylation in S824A/E mutants. Finally, addition of exogenous H2O2 (100–300 μM), and AA (1–10 μM) to a less extent, stimulated S824 phosphorylation of TRPV4 in HCAEC. These results indicate that PKA‐mediated phosphorylation at serine‐824 plays an important role in sensitizing TRPV4 activation by AA. The molecular mechanism by which serine‐824 phosphorylation contributes to AA‐induced TRPV4 activation in coronary endothelial cells remains to be determined.
Endothelin‐1 Blocks BK Channels by Stimulating Protein Kinase C‐Mediated Rab11A Phosphorylation at Serine 177 in Arterial Smooth Muscle Cells
Authors: Zhai Xue , Leo M. Dennis , Jaggar Jonathan H.
Published: November 2023

Large‐conductance calcium (Ca2+)‐activated potassium channels (BK) composed of BKα and auxiliary β1 subunits control arterial myocyte contractility. BKα subunits are primarily plasma membrane‐localized, whereas β1 subunits are stored within intracellular Rab11A‐positive recycling endosomes in arterial myocytes. Nitric oxide (NO) stimulates rapid surface trafficking of auxiliary β1 subunits, which stimulates BK channels, leading to vasodilation. Vasoconstrictors, including endothelin‐1 (ET‐1), inhibit BK channels but mechanisms involved are unclear. Here, using surface biotinylation and immunoFRET microscopy, we found that ET‐1 attenuated NO‐induced surface trafficking of β1 subunits in cerebral artery myocytes. Bisindolylmaleimide‐1 (BIM‐1), a protein kinase C (PKC) inhibitor, blocked this inhibitory effect of ET‐1. Bioinformatic analysis found five potential PKC phosphorylation sites on Rab11A, of which Ser177 had the highest probability. Arterial transfection with a S177A Rab11A mutant blocked ET‐1‐inhibition of β1 surface trafficking. Patch‐clamp experiments indicated that ET‐1‐inhibition of β1 trafficking reduced the ability of NO to increase BK channel open probability (Po). The S177A Rab11A mutant attenuated ET‐1 inhibition of both single BK channel Po and Ca2+ spark‐induced transient BK currents. In summary, our data indicate that ET‐1 stimulates PKC‐mediated phosphorylation of Rab11A at serine 177, which blocks surface trafficking of β1 subunits, leading to BK channel inhibition in arterial myocytes.

Support or Funding Information

NIH/NHLBI grants HL67061 and HL110347
Impaired BKCa channel function in native vascular smooth muscle from diabetic patients
Authors: Nieves‐Cintron Madeline , Buonarati Olivia R , Rigor Robert , Sasse Kent C , Ward Sean M , Hell Johannes W , Navedo Manuel F
Published: November 2023

Increased vascular tone and impaired vascular function are major complications during diabetes. Large‐conductance Ca2+‐activated potassium (BKCa) channels are important regulators of vascular smooth muscle cell contractility and arterial tone. Whereas multiple reports indicate that BKCa channel function is impaired in murine models of diabetes and in immortalized cell lines from diabetic human subjects, whether a similar alteration occurs in native vascular smooth muscle cells from diabetic patients has not been clearly established. Here, we examine and compared BKCa channel function in native vascular smooth muscle cells from obese non‐diabetic and diabetic patients undergoing bariatric surgery using patch‐clamp electrophysiology and confocal microscopy. We found that the amplitude and frequency of spontaneous transient outward currents (STOCs), which are produced by the activation of BKCa channels coupled to Ca2+ sparks, are significantly decreased in human diabetic cells. Ca2+ sparks amplitude and frequency was not different between human non‐diabetic and diabetic cells, indicating that impairment in STOC activity occurs at the BKCa channel level. Consistent with this, BKCa channels in human diabetic cells showed an apparent reduction in Ca2+ sensitivity as compared to non‐diabetic cells. These results suggest impaired BKCa channel function due to aberrant Ca2+ sensitivity in native vascular smooth muscle cells from diabetic patients, which may contribute to the development of vascular complications in humans with diabetes.

Support or Funding Information

This work was supported by grants NIH‐HL098200 and NIH‐HL121059, and AHA‐14GRNT18730054 to MFN.
HuR‐mediated HK2 Downregulation Leads to Coronary Endothelial Dysfunction in Diabetic Mice
Authors: Wang Weihua , Truong Aaron H. , Makino Ayako
Published: November 2023

Ischemic heart disease is the leading cause of mortality in diabetes mellitus and coronary endothelial dysfunction is implicated in the development and progression of cardiac ischemia. HuR (Human antigen R, also known as ELAVL1) is an RNA binding protein which binds to and stabilizes mRNAs that contain AU‐rich elements in 3′‐UTRs. HuR is ubiquitously expressed and regulates many cellular functions via altering mRNAs’ stability. In this study, we explore the role of HuR in coronary endothelial dysfunction in diabetic mice. Type 1 diabetes was induced in mice by high‐dose streptozotocin (STZ) injection and type 2 diabetes by low‐dose STZ injection with high‐fat diet. Mouse coronary endothelial cells (MCECs) were isolated using magnetic beads coated with CD31. The protein levels of HuR in the nuclear and cytosolic fraction were assessed by immunofluorescence staining and western blot. Ribonucleoprotein immunoprecipitation (RIP) was performed to determine the binding of our focus RNAs to HuR in ribonucleoprotein (RNP) complexes. Mitochondrial calcium concentration was measured by Rhod2‐AM staining. Our western blot data demonstrate that MCECs isolated from diabetic mice exhibited significantly lower concentration of HuR in the nuclear fraction, but not in cytoplasm, compared to control. We also confirmed that nuclear HuR expression was markedly reduced in diabetic MCECs using immunofluorescence staining. We predicted the target mRNAs of HuR and performed RIP for those mRNA. Among the mRNAs which we tested, hexokinase 2 (HK2) mRNA was detected in the RNP complex of HuR. Furthermore, we found that the binding of HuR to HK2 mRNA was significantly decreased in MCECs isolated from diabetic mice compared to control. Mitochondrial calcium concentration and the protein expression of voltage dependent anion channel (VDAC), which modulates calcium uptake into mitochondria, were significantly increased and HK2, an endogenous negative regulator of VDAC, was significantly decreased in diabetic MCECs in comparison to control. In addition, HK2 overexpression in diabetic MCECs attenuated mitochondrial calcium uptake toward control levels. In conclusion, our data suggest that decreased HuR level in the nucleus reduces the stability of HK2 mRNA, downregulates HK2 protein expression, and subsequently increases mitochondrial calcium uptake in diabetic MCECs. HuR might be a potential therapeutic target for ischemic heart disease in diabetic patients via restoring coronary endothelial function.

Support or Funding Information

This work was supported by National Heart, Lung, and Blood Institute Grant R01 HL‐115578 (A. Makino)
4‐HNE modified TRPV1 dysfunction leads to loss of capsaicin‐mediated eNOS activity and microvascular dysfunction
Authors: DelloStritto Daniel , Roy Pritam Sinha , Connell Patrick , Fahmy Joseph , Damron Derek , Bratz Ian
Published: November 2023

Our lab has previously demonstrated enhanced 4‐hydroxynonenal (4‐HNE) post‐translational modification (PTM) of TRPV1 decreases TRPV1 functional expression and contributes to microvascular dysfunction in diabetes. Furthermore, recent studies have shown TRPV1 activation elicits eNOS activation and NO production. Accordingly, we hypothesize that the enhanced 4‐HNE‐mediated PTM of TRPV1 contributes to diabetic microvascular dysfunction in db/db mice via decreased eNOS activation and resultant signaling. Contrast echocardiography demonstrated that 4‐HNE decreased capsaicin mediated increases in myocardial blood flow and decreased capsaicin‐mediated relaxation in isolated coronary microvessels. TRPV1 functional analysis using calcium imaging revealed blunted capsaicin‐mediated calcium influx in the presence of 4‐HNE in isolated mouse coronary endothelial cells (MCECs). Finally, 4‐HNE treatment of MCECs decreased eNOS phosphorylation at Ser1197 leading to decreased measure in capsaicin‐mediated nitrate production. Single point mutation, of a pore region cysteine residue 621, rescued channel activity and preserved capsaicin‐mediated eNOS phosphorylation and NO production. These data suggest that TRPV1 is targeted by redox‐active substances that directly modulate channel activity at numerous sites in diabetes to decrease TRPV1 functional expression and contribute to microvascular dysfunction. The results obtained demonstrate a signaling pattern aberrant in TRPV1 regulation of vascular control in diabetes.
Effects of Homocysteic Acid and Estrogen on Behavior in Female Rats
Authors: Barney Chris C. , Loubser Lize , Samuel Shirly , Chase Leah A.
Published: November 2023

Homocysteic acid (HCA) is a neurotoxin that can over stimulate NMDA receptors, leading to neuronal cell death. In humans, hyperhomocystemia, which can lead to elevated HCA levels, has been associated with a variety of disorders, including schizophrenia, depression, Alzheimer's disease, and Parkinson's disease. Previous studies in our laboratory have shown that neonatal administration of HCA causes behavioral changes in female but not male rats. The purpose of the current study study was to determine if the behavioral alterations caused by HCA in female rats were dependent on estrogen levels. Rats were administered HCA intraperitoneally for two weeks starting on day two after birth, housed singly after weaning, and ovariectomized at six and one‐half weeks of age. Half of the HCA treated and half of the control rats had silastic tubes containing estradiol proprionate implanted subcutaneously at the time of ovariectomy. Behavioral testing began three weeks later. Estrogen increased the amount of time the rats spent in the innermost zone in an Open Field Test, increased voluntary running on a running wheel, reduced the number of falls on a RotaRod, increased time to remove tails from hot water, increased saccharine intake, and increased time before giving up in the Forced Swim Test. HCA reduced ambulatory time and distance traveled in the Open Field Test, decreased the number of visits to the open arm in an Elevated Plus Maze test, reduced social interactions in a two‐cage intruder test, and reduced 24 hour retention of the memory of the hidden platform in a Morris Water Maze test. The only significant interactions between HCA and Estrogen were in the ambulatory time and distance traveled in the Open Field Test and in the time spent with the intruder in the social interaction test. This experiment demonstrated that numerous behaviors in rats are estrogen dependent but behavioral responses to HCA are not very estrogen dependent.

Support or Funding Information

Supported by the Hope College Biology Department.
The Role of REM Sleep in the Development of PTSD Using a Rodent Model
Authors: Arias Yvette , Delorme James , Poe Gina
Published: November 2023

Sleep disturbances resulting from an acute trauma predict the development of posttraumatic stress disorder (PTSD) symptoms. Sleep abnormalities can aggravate PTSD and may result in failure of extinction memory, allowing fear to persist. Currently, the electrophysiological properties of sleep that are associated with trauma are not well understood. Rapid eye moment (REM) sleep plays a critical role in memory consolidation and emotional regulation but it may be maladaptive in those experiencing PTSD. We hypothesize that normal, adaptive REM sleep following a traumatic event will lessen the severity of a PTSD‐like phenotype. Male Sprague Dawley rats were REM sleep deprived prior to (n=6) or after (n=6) a single prolonged stress (SPS) protocol (three acute stressors followed by a 7‐day isolation period) to develop a PTSD‐like phenotype, and to assess the contribution of sleep disruption to phenotype development. We evaluated freezing levels on a fear‐associated memory test to assess the severity of the PTSD‐like phenotype in the two sleep deprivation groups compared with controls who never experienced the trauma (n=6) and traumatized rats who were never sleep deprived (n=6). Interestingly, sleep deprivation after the acute phase of SPS and prior to the 7 day isolation period ameliorated the PTSD like symptom of impaired extinction recall a week later. The data suggests that REM sleep deprivation after a traumatic event reduces PTSD‐like phenotype, and that sleep disruption before the trauma exposure did not have a similar effect in rescuing the animals from the posttraumatic disorder symptoms. Our findings, preventing possibly maladaptive sleep following trauma, and timing sleep to adaptive windows normalize later fear extinction abilities. This may be beneficial as part of a treatment for PTSD and other stress associated disorders.

Support or Funding Information

UPR‐PRISE NIH#R25GM096955

University of Michigan SURP 2015
Failure in Central Respiratory 5HT‐Dependent Chemoreception in a Genetic Model of Epilepsy
Authors: Totola Leonardo T , Takakura Ana C , de Oliveira Jose Antonio , Garcia‐Cairasco Norberto , Moreira Thiago S
Published: November 2023

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. There is still a debate in the literature if the respiratory arrest is the primary cause of death. Respiratory chemoreceptors neurons located in retrotrapezoid nucleus (RTN) constitute one of the main groups responsible for controlling breathing automaticity and receive a dense serotonergic innervation. Here, we ask whether alterations of a type of chemoreceptor neurons that expresses the transcription factor Phox2b and is non‐catecholaminergic (Phox2b+/TH−) could affect breathing in a rat model of tonic‐clonic seizures, with susceptibility to audiogenic seizures (the Wistar Audiogenic Rat (WAR) strain (WAR: 340–496 g, n = 6–7). The number of Phox2b+/TH−neurons in the RTN was reduced (79±11%) in WAR. The WARs have reduced resting ventilation (VE) by 35 ±10% and reduced increase in VE elicited by hypercapnia (7% CO2) by 51 ±7%. Furthermore, we also showed that the VE response to serotonin (1 mM ‐ 50 nl) into the RTN region was significantly hampered in WARs due to the reduction in the number of 5‐HT varicosities within the marginal layer of the RTN region. Our results suggest a respiratory disorder, as well as a reduction of the serotonergic neurotransmission within the RTN region, which justify to further use WAR as a suitable model to study increased risk factors and the mechanisms associated with SUDEP

Support or Funding Information

FAPESP, CNPq and CAPES/PROEX
Diastolic Dysfunction and Arrhythmia Incidence are Exacerbated by Central Chemoreflex Activation in HFpEF
Authors: Del Rio Rodrigo , Toledo Camilo , Andrade David C , Lucero Claudia , Aliaga Valentin , Marcus Noah J , Madrid Carlos
Published: November 2023

Heart failure with preserved ejection fraction (HFpEF) is characterized by decreased ventricular compliance and autonomic imbalance. Tonic and episodic chemoreflex activation contributes to autonomic imbalance in heart failure and is associated with poor prognosis. We sought to determine if the sensitivity of central chemoreceptors (CC) is enhanced in an animal model of HFpEF, and whether acute activation of CC exacerbates cardiac dysfunction. Volume overload (a‐v anastomosis) was used to induce HFpEF in adult male Sprague‐Dawley rats. Ventilatory responses to acute hypercapnia (FiCO2‐7% in O2) were measured by plethysmography to assess CC sensitivity, and a conductance catheter was used to measure pressure‐volume relationships as a measure of cardiac function. Neuronal activation was assessed by measuring FosB expression in brainstem micropunches from pre‐sympathetic regions of the rostral ventrolateral medulla (RVLM). Ejection fraction did not differ between HFpEF and sham rats(51±3 vs. 50±7 %, HFpEF vs. sham). HFpEF rats compared to sham rats exhibited cardiac hypertrophy (heart/body weight, 6.1±0.3 vs. 4.0±0.5 mg/g, HFpEF vs. sham), pulmonary congestion (lung wet/dry weight, 4.4±0.1 vs. 3.8±0.1 g/g, HFpEF vs. sham), increased arrhythmia incidence (104±34 vs. 11±2 events/h, HFpEF vs. sham), greater ventricular stiffness (β, 7.4±1.4 vs. 4.3±0.7 mmHg/ml, HFpEF vs. sham), and decreased ventricular active relaxation (τ, 9±2 vs. 15±2 ms, HFpEF vs. sham). In HFpEF rats, CC sensitivity was increased (165.3±9.1 vs. 127.3±10.3 ml/min/100g, HFpEF vs. sham), and CC stimulation (normocapnia vs. hypercapnia) significantly increased (P<.05) arrhythmia incidence (104±34 vs. 1164±204 events/h,) and β (7.4±1.4 vs. 17.5±7.5 1/ml), but did not affect τ values (9±2 vs. 9±1 ms) or significantly compromise ventricular capacitance. RVLM activation (FosB expression) was increased in HFpEF rats compared to sham animals. Our results indicate that the CC is enhanced in in HFpEF, neuronal activation is increased in pre‐sympathetic regions of the brainstem, and acute CC activation further exacerbates diastolic dysfunction and arrhythmia incidence in HFpEF.

Support or Funding Information

Supported by Fondecyt 1140275.
Increased Brain‐derived Neurotrophic Factor in Lumbar Dorsal Root Ganglia Contributes to the Enhanced Skeletal Muscle Afferent Neuronal Excitability via a MAPK‐dependent pathway in Heart Failure
Authors: Wang Hanjun , Rozanski George , Zucker Irving H.
Published: November 2023

An exaggerated exercise pressor reflex (EPR) is associated with excessive sympatho‐excitation and exercise intolerance in the chronic heart failure (CHF) state. A previous study from this laboratory demonstrated that peripheral sensitization of the afferent limb (mainly mechanically sensitive fibers) is an important contributor to the exaggerated EPR in CHF. Here, we hypothesized that brain‐derived neurotrophic factor (BDNF) in muscle afferent neurons plays a critical role in the sensitization of muscle mechanosensitive afferents in CHF. Increased BDNF expression was observed in lumbar DRGs from CHF rats compared to sham rats (8.3±1.1 vs. 19.5±1.8 pg/g, n=6, P<0.05). Immunofluorescence data further showed a greater increase in the number of BDNF‐positive neurons especially in medium and large‐sized DRG subpopulations (mainly mechanically sensitive NF200 positive neurons) from CHF rats compared to sham rats. Patch clamp experiments demonstrated that incubation with BDNF for ~4 hours, dose‐dependently increased the number of action potential (AP) {3.1±0.7 vs. 10.4±2.3; vehicle‐treated (n=16) vs. BDNF‐treated (100 ng/ml, n=17); P<0.001} in response to the same amount of current injection (1.0 nA) in medium‐sized (mainly mechanically sensitive) muscle DRG neurons in sham rats, which was significantly blocked by co‐incubation of the mitogen‐activated protein kinases (MAPK) inhibitor PD98059 (10 μM, 4.3±0.9, n=7; P<0.01). Compared to sham rats, CHF rats exhibited an increased number of AP (14.3±2.6; n=16; P<0.001 vs. sham+vehicle) in response to 1.0 nA current injection in medium‐sized muscle afferent DRG neurons, which was significantly attenuated by 4 hours of incubation with either anti‐BDNF (10 μg/ml, 3.9±1.0; n=11; P<0.001) or PD98059 (10 μM, 5.6±1.4, n=8; P<0.01). These data suggest that increased BDNF in muscle DRG neurons contributes to the enhanced muscle mechanical afferent neuronal excitability via a MAPK‐dependent pathway in the CHF state.

Support or Funding Information

This work was supported by The American Heart Association (#12SDG12040062) and in part, by grants from the National Heart, Lung, and Blood Institute (R01 HL116608‐01A1 and PO1 HL62222).
Cardiopulmonary afferents modulate sympathetically‐mediated heart rate responses to muscle metaboreflex activation in humans
Authors: Souza Mayara C. , Teixeira Andre L. , Nunes Diego , Lopes Paulo M. , Gomes Mauricio D. , Fisher James P. , Vianna Lauro C.
Published: November 2023

The sensory component of the exercise pressor reflex is comprised of group III and IV skeletal muscle afferents that respond to both mechanical (i.e., muscle mechanoreflex) and metabolic (i.e., muscle metaboreflex) stimuli. In humans, isolated muscle metaboreflex activation with post‐exercise ischemia (PEI) has a major effect on increasing sympathetic nerve activity. This can cause peripheral vasoconstriction and partially maintain the exercise‐induced increase in blood pressure. A smaller heart rate response is evoked, which can be blocked by antagonism of b‐1 receptor. The loading of cardiopulmonary baroreceptors, associated with the supine posture, also provides neuromodulatory signals to the brainstem and elicits cardiac sympathoinhibition. Here, we aimed to test the hypothesis that the sympathetically‐mediated heart rate response to muscle metaboreflex activation is blunted by cardiopulmonary loading in men. Nineteen healthy male subjects participated in the study (20 ± 2 years). Beat‐to‐beat blood pressure and heart rate were continuously measured by finger photoplethysmography (ML282B1‐X, AdInstruments). After a rest period a 90‐s static handgrip at 40% maximum voluntary contraction was performed followed by PEI. Trials were conducted with concurrent cardiopulmonary loading (supine posture) or unloading (seated posture). In a subset of subjects (n=5) trials were repeated after b‐1 adrenergic blockade (Atenolol 25 mg). At rest, the shift from supine to seated posture increased heart rate from 64±2 to 69±2 beats.min−1 (P<0.05), whereas blood pressure decreased from 90±2 to 84±2 mmHg (P<0.05). PEI provoked a robust increase in blood pressure from rest (Δ36±3 mmHg, P<0.05), which was not affected by body posture. During upright PEI, heart rate was elevated from rest (Δ10±2 beats.min−1, P<0.05), but blunted with cardiopulmonary loading (Δ2±2 beats.min−1, P>0.05 vs. rest). Following b‐1 adrenergic blockade, the heart rate response to upright PEI was significantly reduced (Δ5±3 beats.min−1, P<0.05), whereas the heart rate response to supine PEI was unaffected (Δ3±2 beats.min−1). In summary, the current study demonstrates that the heart rate response to isolated muscle metaboreflex activation is elevated by cardiopulmonary baroreceptor unloading due to a b‐1 adrenergic mechanism.

Support or Funding Information

CAPES ‐ Coordination for the Improvement of Higher Education PersonnelCNPq ‐ National Council for Scientific and Technological Development
A Role for Cyclooxygenase and Nitric Oxide Synthase in Sweating and Skin Blood Flow During Exercise in the Heat in Young Individuals with Type 1 Diabetes
Authors: Foudil‐bey Imane , Fujii Naoto , Dervis Sheila , Kenny Glen P.
Published: November 2023

Recent studies show that individuals with type 1 diabetes mellitus (T1DM) have impaired heat loss responses. This is evidenced as a decrease in local sweat rate and an increase in core body temperature during exercise in the heat compared to non‐diabetic matches; however, the underlying mechanisms are currently unknown. Previous studies have shown that nitric oxide synthase (NOS) and cyclooxygenase (COX) increase sweating, while NOS, but not COX, contributes to cutaneous vasodilation in young adults exercising in the heat. Thus, the aim of our study was to determine if the impairments in local heat loss responses displayed by individuals with T1DM may be attributed to COX and/or NOS activity. Seven (5 males, 2 females) young (24±3 years) individuals with T1DM were instrumented with four microdialysis fibres in the forearm skin which were perfused with either 1) 10 mM ketorolac (KETO, non‐selective COX inhibitor), 2) 10 mM NG‐nitro‐L‐arginine methyl ester (L‐NAME, non‐selective NOS inhibitor), 3) a combination of L‐NAME and KETO (L‐NAME+KETO), or 4) lactated Ringer (Control). Sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC; laser Doppler perfusion units/mean arterial pressure) were measured continuously throughout the protocol. Participants performed two 30 min bouts of exercise at a fixed rate of heat production of 400 W in the heat (35°C, 20% relative humidity); separated by a 20‐ and 40‐min recovery respectively. During the first and second exercise bouts, we showed that the inhibition of COX (KETO) resulted in an increase in sweat rate relative to Control (average of last 5 min of second exercise; Control: 1.02±0.11 mg min−1 cm−2, KETO: 1.12±0.12 mg min−1 cm−2; P=0.029). However, a decrease in sweat rate was observed when both NOS and COX were inhibited (L‐NAME+KETO: 0.86±0.11 mg min−1 cm−2; P=0.031). Furthermore, inhibition of NOS alone did not significantly modulate sweating (L‐NAME: 0.93±0.11 mg min−1 cm−2; P=0.11). With respect to CVC, the inhibition of NOS (average of last 5 min of second exercise, 45±9%max), as well as NOS and COX (49±4%max) resulted in similar decreases in CVC relative to Control (68±1%max)(both P<0.05). In contrast, the inhibition of COX alone did not modulate CVC (64±4%max; P=0.33). Our results demonstrate that COX attenuates sweating during exercise in the heat in young adults with T1DM, which may occur through NOS‐dependent mechanisms. Finally, we show that individuals with T1DM exhibit NOS‐ but not COX‐dependent cutaneous vasodilation during exercise in the heat.

Support or Funding Information

This study was supported by grants from the Canadian Institutes of Health Research (286363; funds held by Dr. Glen P. Kenny).
Mitochondrial DNA damage is associated with earlier ventilatory threshold in military veterans with unexplained fatigue
Authors: Chen Yang , Jiao Xilu , Klein Jacquelyn , Ndirangu Duncan , Hill Helene Z , Condon Michael , Falvo Michael J
Published: November 2023

Exercise intolerance and post‐exertion fatigueare common symptoms of individuals with mitochondrial dysfunction, and have recently been reported in veterans with unexplained fatigue. The goal of the present study was to assess direct (mtDNA damage) and indirect (cardiopulmonary exercise) measures of mitochondrial dysfunction in fatigued veterans. Twenty‐two(50.0±4.9 years) male veterans volunteered for this study. Each veteran completed general health questionnaire including following items: physical fatigue (44.7±13.8; Fatigue Severity Scale), physical activity questionnaire (1026.4±998.9 MET·min·wk−1), and smoking history (pack years 10.0±13.0). Each veteran provided peripheral blood mononuclear cells for total DNA extraction and mtDNA damage was determined by quantitative polymerase chain reaction. All veterans completed two consecutive maximal exercise tests separated by 24 hours. During each exercise bout, the time of ventilatory threshold (VT) was identified using the v‐slope method. The time of VT was identified as an effort‐independent measure of exercise performance reflective of mitochondrial capacity. MtDNA damage was correlated with physical activity (r=0.54, p= 0.004), time of VT at second b out exercise (r=−0.65, p= 0.001), but was not correlated with pack years, fatigue severity or time of VT at first bout exercise. Using partial correlation by controlling for physical activity and pack years, mtDNA damage was correlated to time of VT at second bout exercise (r=−0.64, p= 0.004). This is the first study to describe mitochondrial dysfunction through the relationship between mtDNA damage and an earlier onset of VT in veterans with unexplained fatigue. This may indicate that post‐exertion fatigue may be related to mitochondrial dysfunction. This work may guide new diagnostic testing and treatments for veterans suffering from with unexplained fatigue.

Support or Funding Information

VA Grants 1I21RX001079‐01 and 1I21CX000797‐01 (Michael J Falvo).
Age‐related arterial immune cell infiltration is attenuated by exercise or caloric restriction
Authors: Trott Daniel Wayne , Henson Grant D , Lesniewski Lisa , Donato Anthony
Published: November 2023

Immune cell infiltration of the vasculature has been shown to play a role in the development of multiple cardiovascular pathologies that also occur with greater frequency in aged populations. To determine if aging increases immune cell infiltration of arteries as well as what immune cell types are involved, we tested the hypothesis that both large elastic and resistance arteries and surrounding perivascular adipose tissue in old mice would exhibit increased immune cell infiltration compared young controls. Additionally, we hypothesized that vasoprotective lifestyle interventions such as 12 weeks of voluntary wheel running or life‐long caloric restriction would attenuate age‐related immune cell infiltration. The aorta and mesenteric vasculature with surrounding perivascular adipose was excised from young (Y, 6–7 months, n = 9), old (O, 28–29 months, n = 9), old voluntary running (OVR, 28–29 months, n = 5) and old caloric restricted (28–29 months, n = 8) mice and digested to a single cell suspension. The cells were then labeled with antibodies against CD45 (total leukocytes), CD3 (pan T cells), CD4 (T helper cells), CD8 (cytotoxic T cells), CD19 (B Cells), CD11b and F4/80 (macrophages) and analyzed by flow cytometry. Total leukocytes per aorta was 5‐fold greater in O compared to Y (p < 0.001), this increase was blunted in OVR (p = 0.063 vs. Y) and completely abolished in OCR (p = 0.662 vs. Y). O aortas exhibited a 3.5‐fold increase in total T cells (p < 0.001), both helper (4‐fold, p < 0.001) and cytotoxic (3‐fold, p < 0.001) T cell subsets, B cells (7‐fold, p < 0.001) and macrophages (4‐fold, p = 0.007). The increases in T cells (p = 0.127 vs. Y), macrophages (p = 0.860 vs. Y) but not B cells (p = 0.002 vs Y) were abolished in OVR mice. Increases in T cells (p = 0.736 vs Y), macrophages (p = 0.606 vs. Y) and B cells (p = 0.692 vs. Y) were abolished OCR mice. In the mesentery, leukocytes were 2.5‐fold greater in O compared to Y both in total number (p < 0.001) and when normalized to tissue weight (3.5‐fold, p < 0.001). In a similar manner to aorta, age‐related increases in T cells and macrophages were attenuated in OVR and OCR and increases in B cells were attenuated only in OCR. These results indicate that immune cells accumulate in both the large elastic and resistance vasculature with age and that either exercise or caloric restriction can blunt this accumulation.
Similar Effects between Follicular and Luteal Phases on the Urinary Levels of 6‐sulfatoxymelatonin following Endurance Exercise
Authors: Yasuda Nobuo , Tanioka Toshihiro
Published: November 2023

The major urinary melatonin catabolite is 6‐sulfatoxymelatonin, which has been demonstrated as a good marker of pineal function. Although previous studies have shown exercise‐induced changes in melatonin metabolism, it still remains inconclusive whether prolonged exercise during two different menstrual cycle phases influences urinary 6‐sulfatoxymelatonin secretion. The purpose of the study was to determine the effects of the follicular and luteal phases on the urinary levels of 6‐sulfatoxymelatonin after 2‐h endurance exercise in women. Eleven recreationally active premenopausal women served as the participants (peak oxygen uptake (VO2peak): 46.1±5.0 mL/kg/min [mean±SD]). During the follicular (F: 5~8 days after the onset of the menses) and luteal (L: 22~25 days after the onset of the menses) phases, all participants carried out the same submaximal exercise protocol (2‐h cycling exercise at 60%VO2peak). Carbohydrate‐electrolyte solution was consumed every twenty minutes (2 ml/kg body mass) during each exercise protocol in order to delay fatigue and prevent hypoglycemia and dehydration. Before (Pre) and after (immediately Post) each exercise, spot urine samples were collected for later analysis of the urinary levels of 6‐sulfatoxymelatonin quantified by enzyme‐linked immunosorbent assay. Regarding the urinary levels of 6‐sulfatoxymelatonin (ng/mg creatinine), two‐way (phase × time) analysis of variances demonstrated a significant main effect for time (p<0.05), but not for phase or interaction (Pre=21.1±3.5, Post=33.0±8.5 for F; Pre=16.3±5.4, Post=33.5±9.5 for L). These findings indicate that acute moderate cycling exercise appears to be similar at the urinary levels of 6‐sulfatoxymelatonin during two different menstrual phases.

Support or Funding Information

Supported partly by funds from the Grant‐in‐Aid for Scientific Research (C) (Grant No.23500867).
The Impact of Neighborhood Food Environment on School Meal Participation Rates
Authors: Vaudrin Nicole , Ohri‐Vachaspati Punam , Green Jessie , Lorts Cori , Yedidia Michael
Published: November 2023

Childhood overweight and obesity is a major public health concern. Schools have been targeted for obesity prevention interventions aimed at improving access and availability of healthier food options, with help from the Healthy, Hunger Free Kids Act of 2010, which strengthened the nutritional standards for meals served at schools. Several studies have assessed the food environment within and around schools for influence on weight and diet quality with mixed results. The objective of the current study is to examine the association between the neighborhood food environment around schools on school meal participation as a percentage of eligibility. We hypothesize that unhealthy food environments around schools are associated with lower rates of school meal participation, as students may be purchasing cheaper, less nutritious food items before or after school in lieu of meals served as part of the National School Lunch Program (NSLP) and the School Breakfast Program (SBP). School level free and reduced‐price meal eligibility and participation rates for 122 Middle and High schools in 4 low‐income, urban New Jersey cities for SY2012–2013 were obtained from the National Center for Education Statistics common core data and from the New Jersey Department of Agriculture using Open Public Records Act request. Food outlets around schools were classified using a protocol developed by a NIH‐funded study. Distance of each school to different types of food outlets will be calculated using geocoded school and food outlet addresses. Included in analysis are 856 convenience stores, 1,448 fast food restaurants, 75 supermarkets, and 46 small grocery stores. Nearly 95% of schools had eligibility rates of at least 50% for free and reduced‐price meals. In terms of race and ethnicity, students enrolled in participating schools were majority Hispanic (48%) and African American (46%). SBP participation rates in the four school districts range from 33% to 63%, and for NSLP from 67% to 81%. Based on analysis from 2009 data, a vast majority of students had easy access (within ¼ mile) to convenience stores (79%) and fast food restaurants (73%) and less access to healthier outlets including small grocery stores (30%) and supermarkets (15%). Results from multivariate analysis examining the association between NSLP and SBP participation and food environment around schools for SY 2012–13, adjusting for school demographics and availability of competitive foods will be presented. A few pioneering cities across the country have enacted zoning laws that set a minimum distance between food outlets offering less healthy items and schools. The current research can be used to further inform the potential effectiveness of such policy decisions.
A More Efficient Method of Assessing Corner Store Healthfulness
Authors: DeWeese Robin , Todd Michael , Karpyn Allison , Yedidia Michael , Kennedy Michelle , Bruening Meg , Wharton Christopher , Ohri‐Vachaspati Punam
Published: November 2023

Introduction

Compared to supermarkets, small/corner stores tend to stock lower proportions of healthy foods. Interventions targeting corner stores to increase healthy foods have been launched in many communities, and validated survey instruments have been developed to evaluate intervention effectiveness. However, in‐store evaluations can be infeasible and resource‐prohibitive due to time requirements. The purpose of this study was to develop a valid and feasible short form corner store audit tool (SCAT) that could be used in‐store or over the phone to capture the healthfulness of corner stores.

Methods

An adapted version of the Nutrition Environment Measures Survey for Corner Stores (NEMS‐CS) was used to conduct store audits of 229 corner stores in four New Jersey cities in 2014. Audit results were used in exploratory factor analysis and item response theory to develop the SCAT. In 2014 and 2015, a second round of audits was conducted in 96 corner stores to confirm the validity of the SCAT and to test its feasibility as a phone audit tool.

Results

The SCAT was highly correlated with the adapted NEMS‐CS (r=0.79). SCAT scores placed stores in the same healthfulness categories as did the adapted NEMS‐CS in 88% of cases. Phone response matches indicated that store owners did not distinguish between 2% and low‐fat milk, and tended to round up the fruit and vegetable count to five if they had fewer varieties.

Conclusion

The SCAT discriminates between higher versus lower healthfulness scores of corner stores and is feasible for use as a phone audit tool.

Support or Funding Information

This research was funded by a National Institute of Food and Agriculture predoctoral dissertation fellowship (20146701122279) and by a grant from the National Institute of Child Health and Human Development (1R01HD071583‐01A1)
A Novel Approach for Determining the Environmental Impacts of Individual Food Choices in the United States
Authors: Rose Diego , Heller Martin , Willits‐Smith Amelia , Mundorf Adrienne R. , Keoleian Gregory
Published: November 2023

USDA and DHHS excluded sustainability as a topic for consideration in developing the 2015 Dietary Guidelines for Americans, contrary to recommendations by an expert advisory committee. While significant progress has been made in Europe and elsewhere in documenting the environmental impacts of different diets, very little work on this has been undertaken in the US, which might help explain their decision. To address this gap, we developed a novel approach to study the environmental impacts of individual food choices in the US. Individual 24‐hour recall data (N=28,276) from the National Health and Nutrition Examination Survey for 2005–2010 were converted to commodity form using resources from the US Environmental Protection Agency. There were 2.63 million food item/recipe components consumed by these individuals on the two days of recall, and these were converted to 461 different commodities. The environmental impacts of these food commodities – principally greenhouse gas emissions – were obtained from a comprehensive review of published life cycle assessment (LCA) studies. The LCA approach assesses inputs and outputs in the production, distribution, and consumption of products, and has seen increased application to foods in recent years. By matching the food choices of individuals to environmental impacts, we can quantify the impact of dietary choices on greenhouse gas emissions and other environmental impacts. Using aggregate agricultural food balance sheet data, we previously estimated mean greenhouse gas emissions from the U.S. diet to be 5.0 kg of carbon dioxide equivalents per person per day. The approach reported here will allow us to refine that estimate, and analyze the variation in the US population of this outcome by demographic and socio‐economic characteristics, as well as by diet knowledge and health behaviors. This cross‐disciplinary research demonstrates an approach that can inform future policy discussions regarding dietary recommendations and their potential impacts on sustainability.

Support or Funding Information

This work was supported by the Wellcome Trust (grant # 106854/Z/15/Z).