bluuebunny/crossref_metadata_2025 huggingface dataset:
Sympathetic hyperinnervation in obesity is associated with oxidative stress and inflammatory cell NGF synthesis
Authors: Haddock Rebecca Ellen , Hill Caryl E , Sobey Christoper G , Drummond Grant R
Published: June 2021

Obesity is associated with an increased density of the sympathetic nerve plexus over arteries that control blood pressure. Here we examine the role of oxidative stress and inflammatory cell infiltration to changes in perivascular nerve innervation over small mesenteric arteries from C57BL/6 and NOX2−/− mice fed a normal or high fat diet. Changes in smooth muscle membrane potential were measured in response to perivascular nerve stimulation. Innervation density, nerve growth factor (NGF) and inflammatory cell type were examined by immunohistochemistry. Oxidative stress was measured using dihydroethidium fluorescence. Denser nerve plexuses over arteries from obese C57BL/6 mice were associated with larger excitatory junction potentials (EJPs; P<0.05). Oxidative stress and numbers of inflammatory cells positive for NGF were also increased (P<0.05). By contrast, the perivascular nerve plexus in obese NOX2−/− mice was less dense (P<0.05) and EJP amplitude was decreased (P<0.05). Oxidative stress and numbers of NGF positive inflammatory cells were also decreased (P<0.05). We demonstrate that obesity causes an increase in the density of the sympathetic nerve plexus via NOX2dependent and independent processes. Hyperinnervation occurs due to increased oxidative stress and infiltration of NGF producing inflammatory cells. This study was supported by the NHMRC to REH (466009).
Cerebroprotective effects of selective head cooling during epileptic seizures
Authors: Parfenova Helena , Harsono Mimily , Liu Jianxiong , Basuroy Shyamali , Jolly Elliott J , de Jongh Curry Amy , Zhuang Daming , Leffler Charles W. , Pourcyrous Massroor
Published: June 2021

Epileptic seizures in newborn pigs induce apoptosis in cerebral endothelial cells resulting in reduction of endothelial‐dependent cerebrovascular function. We hypothesized that selective head cooling during seizures reduces apoptosis and prevents postictal cerebral vascular endothelial dysfunction. Seizures were induced by bicuculline in anesthetized and pancuronium‐immobilized piglets. For selective head cooling, ice packs were placed around the skull during seizures. Head cooling decreased core temperature from 37.2 ± 0.2 to 35.3 ± 0.40 C and reduced pial arteriolar diameter and heart rate, whereas blood pressure was not altered. After 48 h of recovery, cerebral vascular responses to endothelium‐dependent dilators (bradykinin, glutamate, hemin) were assessed using cranial window microscopy. In the normal temperature group, apoptotic changes in cerebral vessels detected by TUNEL staining were accompanied by reduced vasodilator responses. In the head cooling group, no apoptotic cerebral vascular cells were detected, and cerebral vascular reactivity was preserved during postictal period. Overall, head cooling during seizures prevents apoptosis and sustained loss of cerebral vascular function. Cerebroprotective effects of head cooling counteract loss of cerebral blood flow regulation and may be beneficial for neuronal survival in neonatal seizures. The study is supported by NIH/NINDS.
Biotelemetry of intracranial pressure in freely moving rats: a detailed description of surgical implantation for chronic studies
Authors: McLeod Damian , Murtha Lucy , Burke Julia , Pitsillides Koullis
Published: June 2021

We aimed to develop a minimally invasive surgical technique for implantation of a biotelemetry device (EG3‐V0S1T, Transonic EndoGear Inc, Davis, CA), for chronic measurement of intracranial pressure (ICP) in freely moving rats. Under surgical anesthesia, a 2 cm midline scalp incision and blunt dissection exposes the skull surface. Two 1 mm shallow grooves are burred in the right and left parietal bones at 4 mm lateral to bregma for positioning of two 1 mm securing screws, which anchor a 2 mm layer of dental cement to the skull. Once dry, a 1 cm channel is burred through the dental cement, 2.5 mm lateral and parallel to the skull midline over one parietal bone. At the cranial end of the channel, a 2 mm hole is burred through the skull being careful to leave the meninges intact. The biotelemetry implant with battery connected is buried subcutaneously after making a 3 cm intrascapular skin incision. A 3F solid‐state pressure catheter, connected to the implant, is tunneled under the skin from the intrascapular region to exit at the scalp incision site. A 0.5 mm incision is made in the dura mater with a 30G needle tip and the pressure sensor head positioned under the dura. A thin layer of biocompatible caulking material is applied over the catheter head, and another layer of dental cement is applied to seal the cranial vault and ensure no movement of the pressure sensor head for chronic measurement of ICP.
Hypertension‐induced endothelial dysfunction and posterior communicating artery remodeling
Authors: Pires Paulo Wagner , Dorrance Anne McLaren
Published: June 2021

Hypertension‐induced endothelial dysfunction and remodeling of arteries in the circle of Willis can impair blood flow after permanent middle cerebral artery (MCA) occlusion. The posterior communicating artery (PComA) connects the basilar and posterior cerebral artery (PCA). The PCA forms anastomoses with the MCA, thus flow through the PComA/PCA can improve perfusion of the MCA territory. The effects of hypertension on PComAs are unknown; we hypothesized that hypertension will lead to inward remodeling and endothelial dysfunction. PComAs from adult male stroke‐prone spontaneously hypertensive rats (SHRSP, n=3) were studied using pressure myography. Wistar‐Kyoto (WKY) rats were controls (n=5). Data are means±SEM, SHRSP vs WKY rats. Dilation to 2‐methylthio‐ATP was impaired in SHRSP (change in diameter at 10μM: 17.6±6 vs 24.5±3μm, p<0.05). At 80mmHg, the lumen diameter (172±17 vs 205±17μm, p<0.05) and distensibility (49±6 vs 61±5%, p<0.05) of PComAs from SHRSP were reduced and the wall thickness (15±1 vs 12±1, p<0.05) and wall/lumen ratio (0.09±0.01 vs 0.06±0.01, p<0.05) were increased. These data suggest that hypertension causes endothelial dysfunction and inward remodeling of the PComA and this may reduce collateral blood flow after permanent cerebral ischemia.
Translational regulation of the mitochondrial genome following redistribution of mitochondrial microRNA (MitomiR) in the diabetic heart.
Authors: Jagannathan Rajaganapathi , Thapa Dharendra , Baseler Walter A , Shepherd Danielle L , Croston Tara L , Nichols Cody E , Lewis Sara E , Hollander John M
Published: June 2021

Cardiomyocytes contain mitochondria that are situated in distinct subcellular regions, termed subsarcolemmal mitochondria (SSM), and interfibrillar mitochondria (IFM). We have identified a functional pool of mitochondrial microRNAs (mitomiRs) that are redistributed in spatially‐distinct mitochondrial subpopulations in response to diabetic mellitus. We observed an inverse distribution pattern between SSM and IFM following diabetic insult such that greater than 54% of identified mitomiRs were inversely distributed between the two subpopulations. Specific tri‐nucleotide sequence motifs (UGG and AGG) were observed in the seeding region of identified mitomiRs which may be predictive for distribution in the mitochondrion. Redistributed mitomiRs displayed interactions with the mitochondrial genome requiring association with RISC proteins (AGO2 and FXR1) for translational regulation. Redistribution of mitomiR‐378 to the IFM following type 1 diabetic insult led to a down regulation of mitochondrially‐encoded F0 components ATP6 and ATP8. We propose that mitomiR translational regulation of mitochondrially‐encoded proteins oscillates in mitochondrial subpopulations in response to type 1 diabetic insult, suggesting a dynamic system that can regulate the mitochondrial genome during pathological states in a spatiallydistinct manner.(Support: NIH DP2DK083095, NIH T32HL090610, DGE‐1144676)
Diabetic mouse hearts: a good predictor for the human population?
Authors: Croston Tara L. , Holden Anthony A. , Tveter Kevin , Lewis Sara E. , Thapa Dharendra , Shepherd Danielle L. , Nichols Cody E. , Jagannathan Rajaganapathi , Hollander John M.
Published: June 2021

Mitochondrial dysfunction is an underlying cause of mortality in type 2 diabetic patients. Two cardiac mitochondrial subpopulations exist, subsarcolemmal (SSM) and interfibrillar (IFM). We have previously reported decreased SSM function in type 2 db/db mouse heart. Currently, subpopulation based mitochondrial analyses have not been explored in type 2 diabetic human heart. The goal of this study was to examine the impact of type 2 diabetic insult on mitochondrial function in the human heart and determine if the db/db mouse model is a reasonable prediction tool for the human condition. Mitochondrial subpopulations were isolated from atrial appendages of non‐diabetic (ND) and type 2 diabetic (DM). Membrane potential and protein import rates were higher in IFM as compared to SSM consistent with data from mouse models. State 3 respiration rates were decreased in DM SSM as compared to ND SSM (P<0.05), with no change in IFM. Electron transport chain complex I activity was decreased in DM SSM as compared to ND SSM (P<0.05), with no difference in complexes III and IV activities for either subpopulation. Mortalin, an import protein, was decreased in DM SSM. Overall, the results suggest that mitochondrial dysfunction observed during type 2 diabetic insult in the human heart is similar with results from the db/db mouse model and suggest that SSM are impacted to a greater extent than IFM. (Supported: NIH‐DP2DK083095, 5T32HL090610)
Co‐immunolocalizing proteins involved in fructose metabolism and calcitriol regulation in the rat kidney
Authors: Dorcinvil Marline , Douard Veronique , Fritzky Luke , Lagunoff David , Sabbagh Yves , Ferraris Ronaldo P.
Published: June 2021

In rodents chronically consuming high fructose diets, serum calcitriol levels decrease markedly and may be linked to increases in serum levels of FGF23 known to regulate expression of CYP27B1 and CYP24A1 that metabolize this active form of vitamin D. To determine the cell types involved in this complex interaction, we used immunohistochemistry of renal biomarkers of fructose metabolism (its transporter GLUT5 and fructokinase (FK)), of FGF23 effects (klotho, the obligate renal FGF23 coreceptor) as well as established biomarkers of proximal (the phosphate cotransporter NaPi2a) and distal (peanut agglutinin (PNA)) tubule cells. NaPi2a but not PNA colocalized with GLUT5 and FK, while GLUT5 colocalized also with FK. Compared to glucose or starch, fructose‐feeding markedly increased expression of GLUT5 and decreased that of NaPi2a. Thus dietary fructose regulates renal fructose transport and metabolism occurring primarily in proximal and not distal tubule cells. In contrast, PNA, but not NaPi2a, GLUT5 and FK, colocalized with klotho, suggesting that klotho and FGF23 regulation occurs mainly in the distal tubule, contrary to most findings, and that fructose metabolism in the proximal tubule may not directly interact with klotho‐regulated calcitriol metabolism. (NSF‐IOS1121049)
Nrf2 antioxidant pathway activation attenuates renal ischemia/reperfusion (I/R)‐induced alterations in biomarkers
Authors: Richards Toni L. , Ida Kevin K. , Horn Todd R. , Kandlikar Sachin S. , Plato Craig F.
Published: June 2021

Acute kidney injury (AKI) secondary to acute renal ischemia is associated with high mortality and morbidity. Oxidative stress is a key component of renal I/R injury making the Nrf2 antioxidant pathway a target to lessen AKI. We evaluated bardoxolone methyl's (BARD) ability to activate the Nrf2 pathway and attenuate I/R‐induced urine biomarkers. At d‐2, rats received (po, bid for study duration) vehicle (Veh) or BARD (0.3, 1, 3, or 30 mg/kg). At d0, rats underwent sham (n=6) or 40 min of warm, bilateral renal I/R (n=10/group) surgery using our proprietary vascular clamp. Rats were single‐housed in metabolic cages for balance of study. 24 and 48 hrs post‐reperfusion, urine volumes were determined and sampled. Clinical chemistry and ELISAs were applied to urine analysis; renal mRNA was quantitated using Luminex. BARD increased renal cortical Nqo1 mRNA expression (917% vs. Veh) indicating Nrf2 pathway activation. I/R increased proteinuria by 728% at 24 hrs relative to sham. 0.3–3 mg/kg BARD attenuated I/R‐induced proteinuria (avg. of 57% vs. Veh). I/R timedependently increased urinary Kim‐1 (4843% at 48 hrs) and NGAL (2962% at 48 hrs) excretion compared to sham. 1 and 3 mg/kg BARD attenuated I/R‐induced increases in Kim‐1 (57% and 93% vs. Veh, respectively) and NGAL (65% and 81% vs. Veh, respectively) excretion. In conclusion, Nrf2 pathway activation effectively inhibits I/R‐induced increases in urinary AKI biomarkers.
Evaluation of the role of the NAD(P)H oxidase subunit p67phox in the regulation of medullary blood flow in Dahl S rats
Authors: Evans Louise Christine , Ryan Robert , Kurth Terry , Skelton Meredith , Cowley Allen
Published: June 2021

Studies were performed in male Dahl salt‐sensitive rats (SS; SS/JrHsdMcwi) and SS rats with a null mutation in the p67phox gene (SSp67phox null mutant; SS‐Ncf2em1Mcwi+/+) aged 10–12 weeks (n=5/group) and maintained from birth on a 0.4% NaCl diet (LS). Optical fibers were implanted in the renal medulla and medullary blood flow (MBF) measured in the conscious animal by laser‐Doppler flowmetry. Mean arterial pressure (MAP) was measured from indwelling carotid catheters by telemetry. Following a 7 day recovery from surgery, baseline measurements of MAP and MBF were made daily to obtain 3 stable control days on LS. Rats were then switched to 4% NaCl diet (HS) and MAP and MBF measured over 7 days. During the LS period, MAP was comparable between SS (127±2mmHg) and p67phox null (121±3mmHg) rats. HS caused a rapid and sustained decrease in MBF in SS rats which was significantly different from LS by day 2 (reduction of 23±4%, p<0.05). Reduced MBF was associated with a progressive increase in MAP which averaged 149±4mmHg at day 7. HS had no significant effect on MBF in SSp67phoxnull rats and the pressor response was blunted, MAP averaged 133±8mmHg at day 7. In summary, when p67phox is not functional in the SS rat HS does not affect MBF and salt‐sensitive hypertension is attenuated. This suggests that p67phox contributes to the increased oxidative stress in the renal medulla associated with salt induced hypertension.
PPARγ agonist inhibition of cyst growth in the W‐WPK rat model of polycystic kidney disease assessed by CT scans
Authors: Flaig Stephanie M. , Carr Alexander , Ai Huisi , Gattone Vincent , Blazer‐Yost Bonnie
Published: June 2021

Polycystic kidney diseases (PKD) are genetic disorders characterized by fluid‐filled cysts in kidney tubules and liver bile ducts. Cyst enlargement is due, at least in part, to Cl− secretion via the cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel. Previous studies demonstrated that PPARγ agonists, pioglitazone and rosiglitazone, insulin sensitizing drugs used to treat diabetes, inhibit Cl− secretion in collecting duct cells via decreased CFTR synthesis. Our preclinical studies showed that pioglitazone and low (0.04 mg/kg BW) dose rosiglitazone inhibited cyst growth in the PCK rat model of PKD. The current study was designed to study the effect of the agonists in an alternative PDK model and to determine if CT scans could be used to track the progress of disease and drug therapy. W‐WPK rats, a rapidly progressing model, were fed a diet containing pioglitazone (20 and 2 mg/kg BW) from day 5 to 18. In agreement with previous studies, the lower dose was the most effective in reducing cyst growth. The CT scans proved to be effective in determining the progress of the disease and yielded results that correlated well with post‐sacrifice analyses. Funding: CTSI grant ‐ IUSM
Inhibition of Src kinase activity reduces heart rate with slight alteration of heart rate variability
Authors: Jiang Jyun Hao , Ho Jamie , Phan Nhut Nam , Tian Duong Thuy , Do Thi Duyen , Chang Howard , Lin Yen‐Chang
Published: June 2021

Heart rate variability (HRV) is the cardiac index representing the oscillation of the intervals between consecutive heartbeats (RR intervals in the ECG). It reflects the influences of the autonomic nervous system (ANS) on the sinus node. In order to investigate the involvement of tyrosine phosphorylation in cardiac function of the whole rat system and its effect on HRV, we employed a potent selective inhibitor of Src family kinases, PP2, to inhibit the activity of Src kinases that include Src, Fyn, and Yes.

Heart rate was decreased 20% by PP2 at the dose of 0.2 mg/kg. PP3, a negative control compound of PP2, which does not inhibit the activity of Src kinases decreased heart rate by 8% (when at the identical dose of 0.2 mg/kg) when compared with the basal. Interestingly, HRV was not significantly altered at a relatively low dose of PP2 (0.2 mg/kg) when compared with that of PP3 or the basal. Unlike that of PP2, HRV was significantly decreased after application of 0.4 μg/kg isoproterenol. Similar to that of PP2, ZD7288, a specific inhibitor of Hyperpolarized Cyclic‐Nucleotide gated (HCN) pacemaker channels, when at the low dose of 0.2 mg/kg, was able to decrease the heart rate without significant change of HRV in comparison to isoproterenol.

Overall, PP2, like ZD7288, can serve as a potential candidate in the treatment of tachycardia‐induced arrhythmias via inhibition of Src‐mediated tyrosine phosphorylation.
Sudden Cardiac Death in a Severe Form of Childhood Epilepsy: Mice & Men
Authors: Auerbach David S , Shi Huilin , Jones Julie , Clawson Brittany C , Ogiwara Ikuo , Yamakawa Kazuhiro , Meisler Miriam H , Parent Jack M , Isom Lori L
Published: June 2021

Dravet Syndrome (DS) is a severe form of epilepsy and SUDEP: Sudden Unexplained Death in EPilepsy. Cardiac arrhythmias are a proposed cause of SUDEP in DS, yet, the incidence and mechanisms remain unknown. Over 80% of DS patients have SCN1A mutations, encoding the Na+ channel, Nav1.1. We hypothesized DS SCN1A mutations result in altered cardiac electrical function, arrhythmias, and a cardiac mechanism for SUDEP. Cardiomyocyte Na+ current (INa), action potentials (APs), and ECG recordings were acquired from DS and WT juvenile mice, and Control and DS (DS1&2) patient induced‐pluripotent stem cell derived cardiomyocytes (iPSC‐CMs). DS mice have increased INa, excitability, AP prolongation, and incidence of early after‐depolarizations, a substrate for arrhythmias. While no WT mice died, 21% of DS mice died by P152, 69% of these deaths by P52. DS mice exhibited seizures, QT prolongation, ventricular ectopic foci, beat‐to‐beat variability, arrhythmias, bradycardia, and death. Also, iPSC‐CMs from DS1 exhibited increased INa vs Control, while no change in DS2. This demonstrates the differing DS disease penetrance. In DS, increased INa is a substrate for arrhythmogenesis, may provide non‐invasive SUDEP biomarkers, and provide a potential mechanism for SUDEP.
The Sialyltransferase, ST3Gal4, Modulates Ventricular Electrical Signaling
Authors: Ednie Andrew R , Horton Kofi‐Kermit , Wu Jiashin , Bennett Eric S
Published: June 2021

Sialic acids impact voltage‐gated Na+ channel (Nav) and K+ channel (Kv) function, but little is understood about how the glycosylation machinery influences electrical signaling. Diseases of glycosylation often cause symptoms consistent with changes in excitability that include arrhythmias. The sialyltransferase, ST3Gal4, is uniformly expressed throughout cardiac chambers and developmental stages. An ST3Gal4 knockout strain was used to investigate the role of sialylation in the cardiac electrical remodeling often associated with diseases of glycosylation. Data indicate ST3Gal4 deletion significantly affects Nav gating with no change in maximum current density. Activation voltages of voltage‐dependent kinetic components of K+ currents (IK), Ito and IKslow, were depolarized, along with a reduction in peak IK density. The ST3Gal4−/− ventricular myocyte refractory period was reduced and action potential waveform alterations were observed. Consistently, ST3Gal4−/− left ventricular epicardium demonstrated a reduced refractory period and was more susceptible to arrhythmias as observed through isolated whole heart optical mapping studies. The data indicate that relatively minor perturbations in the glycome cause significant changes in cardiac electrical signaling, highlighting the role of glycosylation in cardiac function. Additionally, these studies underscore the possible contribution of reduced sialylation as a mediator for the often observed changes in electrical excitability associated with diseases of glycosylation.
Glucocorticoid signaling in Polycystin 1 (PC1) null endothelial cells
Authors: Jones Thomas Jospeh , Adapala Ravi K. , Burke Jamie R. , Shubbar Ahmed S. , Thodeti Charles K.
Published: June 2021

Endothelial mutations in PC1 are associated with the common and incurable adult onset hereditary kidney disease, autosomal‐dominant polycystic kidney disease (ADPKD). PC1 mutations correlate with decreases in eNOS expression and NO production. Inflammation is also present with elevated glucocorticoids that contribute to ADPKD. However, their contribution to PC1 null endothelial dysfunctions is unknown. Chronic glucocorticoids suppress eNOS expression and can acutely blunt eNOS coupling. We found that PC1 null cells chronically exposed to to the synthetic glucocorticoid, dexamethasone, led to an enriched concentration dependent decrease in eNOS expression compared to Wt. We also found that this decrease in eNOS expression was correlated with a decrease in eNOS promoter activity. Further, we demonstrate that PC1 and dexamethasone mediate potentiation of minimal glucocorticoid receptor (GR) promoter activity compared to Wt, although glucocorticoid receptor expression was similar. Moreover, PC1 null endothelial cells exhibited a decrease in eNOS coupling compared to the Wt that was enhanced by the acute of dexamethasone. These results demonstrate mechanisms by which persistent high levels of glucocorticoids can contribute to ADPKD endothelial dysfunction.
Cardiopulmonary Fitness and Cognitive Function in Midlife: Associations with Central Elastic Arterial Stiffness and Regional Cerebral Perfusion
Authors: Tarumi Takashi , Gonzales Mitzi M , Fallow Bennett , Nualnim Nantinee , Tanaka Hirofumi , Haley Andreana P
Published: June 2021

Central elastic arterial stiffness is associated with accelerated brain aging and cognitive decline. By contrast, habitual aerobic exercise reduces central arterial stiffness and is related to lower risk of dementia in late life.

Purpose

To determine the associations among cardiopulmonary fitness, central arterial stiffness, cognitive function, and regional cerebral perfusion in sedentary and endurance‐trained middle‐aged adults.

Methods

Maximal oxygen consumption (VO2max), neuropsychological assessment, central arterial stiffness, and regional cerebral perfusion were measured in 27 healthy sedentary (53±1 years) and 32 endurance‐trained (52±1 years) adults.

Results

The endurance‐trained subjects exhibited greater levels of VO2max, cognitive functions in total composite, memory, and attention‐executive function, and occipito‐parietal blood flow and lower central arterial stiffness than in sedentary subjects (all P<0.05). Carotid distensibility was significantly associated with both VO2max (r=0.28, P=0.046) and total cognitive composite score (r=0.30, P<0.05). Furthermore, central artery stiffness was negatively correlated with occipito‐parietal blood flow (r=−0.41–0.44, P<0.05).

Conclusions

Lower central arterial stiffness in endurance‐trained adults is associated with greater cognitive function and occipito‐parietal perfusion.
Influence of sex and training status on cardiac and baroreceptor function following combined high‐intensity interval exercise and orthostatic stress
Authors: Cote Anita T , Phillips Aaron A , Bredin Shannon SD , Koehle Michael S , Warburton Darren ER
Published: June 2021

Training status and sex have been shown to impact sympathetic activation with intense exercise, and tolerance to orthostatic challenges. The purpose of this investigation was to assess the effects of sex and training status on cardiac and autonomic responses following high‐intensity interval exercise (HIT) and lower body negative pressure (LBNP). We hypothesized that endurance‐trained (ET) females would display greatest decrements. Ventricular function (echocardiography) and baroreceptor sensitivity (BRS) were assessed in 33(13f) normally active (NA) and ET subjects during LBNP (0, −20, −40 and −60 mmHg), before and after HIT (15 bouts of 1:2 min work:recovery cycling at 100 and 40%, respectively). A three‐way mixed model ANOVA was used to compare dependent variables between sex and training status, within LBNP and condition. Men and women responded similarly to combined HIT and LBNP. Throughout, women displayed enhanced strain, diastolic strain rate, and BRS (P>;0.05). Pre‐exercise BRS decreased greater in ET than NA (0 to −60 mmHg: NA, 17.3±12.8 to 17.0±17.5; ET, 26.1±10.5 to 16.9±4.1, ms/mmHg), but post‐exercise, recovery of BRS was more rapid in ET (NA, 9.6±5.0 to 9.4±5.5; ET, 8.2±4.4 to 13.5±7.6, ms/mmHg; P<0.01). In conclusion, it would appear that the cardiac and autonomic stability of ET and women during an orthostatic challenge is not compromised in the face of short (45 min) high‐intensity training.
Performing Resistance Exercise Prior to Aerobic Exercise Results in Higher Growth Hormone Levels during Exercise in Physically Active Individuals with Well‐Controlled Type 1 Diabetes
Authors: Yardley Jane Elizabeth , Sigal Ronald J. , Perkins Bruce A. , Riddell Michael C. , Kenny Glen P.
Published: June 2021

Background

Performing resistance exercise before aerobic exercise (rather than the reverse) can protect against exercise‐induced hypoglycemia in physically active well‐controlled individuals with type 1 diabetes (T1D). Growth hormone (GH) is a potential mediator of this phenomenon as it promotes lipolysis, thereby sparing blood glucose.

Purpose

This research aimed to determine whether GH secretion is affected by the order in which resistance (R) and aerobic (A) exercise are performed in people with T1D.

Methods

On separate days, 6 physically active participants with T1D (HbA1c 7.0±1.0%) either ran on a treadmill for 45‐min prior to performing 45‐min of weight lifting (AR) or performed the resistance exercise before running (RA).

Results

GH (mean±SE) rose only transiently in AR, but the rise was larger and more sustained in RA. Differences between sessions were statistically significant for the last 30‐min of exercise (mean at 60 minutes: AR = 2.86±1.03 vs RA = 5.86±1.91 μg/L; at 75 minutes: AR = 1.98±0.78 vs RA = 7.17±2.54 μg/L; at 90 minutes: AR = 1.98±0.82 vs RA = 6.67±2.51 μg/L.

Conclusion

GH patterns are consistent with this hormone being a mediator in the stabilization of blood glucose levels when aerobic exercise is performed subsequent to resistance exercise in habitually active individuals with T1D. Supported by the Canadian Diabetes Association and the Ottawa Hospital Research Institute.
Functional and morphological changes in the trout heart during thermal acclimation
Authors: Klaiman Jordan M , Pyle W Glen , Gillis Todd E
Published: June 2021

Rainbow trout remain active in waters that seasonally change between 4ºC and 20ºC. We have previously shown that when male trout are thermally acclimated to the extremes of this temperature range two distinctive cardiac phenotypes emerge. Cardiac hypertrophy is observed in the cold acclimated fish with a concurrent increase in connective tissue and a decrease in the thickness of the compact myocardium, while the opposite occurs in warm acclimated trout. The opposing effects of cold and warm acclimation suggest that male trout can reversibly remodel the morphology and cellular composition of the heart, making the myocardium extremely plastic to changes in environmental temperature. In this study, we use a Langendorff preparation to measure how thermal acclimation and the subsequent cardiac remodeling affects the contractility of the trout heart. With this method we are able to measure maximum systolic and end diastolic pressure. We hypothesized that the increase in connective tissue in cold acclimated males would cause stiffening of the ventricle. Interestingly, preliminary data indicates that the cold acclimated male heart is more compliant then the warm acclimated male heart. This suggests that the remodeling of the myocardial layers has a greater impact on the compliance of the trout heart then connective tissue changes.
The Effects of Soil pH and Composition on Blacklegged Tick Molting Success
Authors: Ahern Kaleigh Erin , LoGiudice Kathleen
Published: June 2021

The blacklegged tick (Ixodes scapularis), commonly known for spreading Lyme disease, is one of the most significant vectors of infectious disease in the world. Both the range of the blacklegged tick and annual incidence of Lyme are increasing in North America, stressing the importance of understanding what environmental factors impact tick survival. Past studies have shown these factors include rainfall, groundcover, plant and animal community composition, temperature, and soils. Because ticks spend much of their lives in contact with soil, it is not unreasonable to assume soil type and pH can impact tick survival, yet this interaction is arguably one of the most poorly understood. The Albany Pine Bush Preserve in Albany, New York is characterized by acidic loam‐sand soils that support very high tick densities. To test the effects of soil type and pH on ticks, chipmunk‐fed engorged nymphal ticks were collected from the Pine Bush and placed in 4 soil treatments: sand moistened with an acidic solution (buffer), sand moistened with basic buffer, acidic Pine Bush soil, and CaCO3 altered basic Pine Bush soil. Results suggest molting success was higher in acidic soils than basic soils and higher in Pine Bush soils than sands. Further research may aid in predicting future range expansion and disease exposure, potentially adding insight into tick control methods. Funding: Mellon Foundation Grant to UC ESPE and NSF #EF‐0812946.
Hypoxia Induced Intrauterine Growth Restriction (IUGR) in the Rat
Authors: Winters Cody Allen , Arroyo Juan Alberto
Published: June 2021

Intrauterine growth restriction (IUGR) is a significant obstetric complication that affects up to 8% of all pregnancies. It is known that the IUGR fetus and newborn are at significant risk for morbidity and mortality. Furthermore, studies have shown a correlation between IUGR and the adult offset of hypertension and coronary heart disease. A number of placental abnormalities have been described in IUGR including an increase in trophoblast apoptosis and aberrant trophoblast invasion. The objective of this project is to develop and characterize a new hypoxia induced model of IUGR. Rats were treated with hypoxia (9%) for 4 days. At the time of necropsy placental, fetal and conceptus numbers were recorded. Immunohistochemistry was done to determine to level of trophoblast invasion and apoptotic molecules for the invasive trophoblast cells. Western blot was used to determine apoptotic proteins activation in the placenta. We observed: 1) decreased placental (21%) and fetal (24%) weights (p<0.05); 2) no significant differences in conceptus numbers; 3) decreased trophoblast invasion as measured by cytokeratin 7 immunostaining; 4) increased trophoblast active caspase 3 (25%) and an increased trophoblast XIAP (23%) protein (p<0.05). We conclude that hypoxia treatment to pregnant rats at mid‐gestation induces IUGR. This was coupled with an increase in apoptosis in both the placenta and mesometrial compartment of the treated animals and a decreased in trophoblast invasion. This model will give some avenues for the study placental development prior to term during IUGR.
Gene expression associated with acute mountain sickness in healthy adults rapidly transported to high altitude
Authors: Herman Nicole Marie , Grill Diane E , Anderson Paul J , Miller Andrew D , O'Malley Kathy A , Johnson Jacob B , Richert Maile L Ceridon , Johnson Bruce D
Published: June 2021

Objective

To identify novel genes and pathways associated with acute mountain sickness (AMS).

Background

The uniform, rapid transfer of adults from McMurdo Station (sea level, SL) in Antarctica to the South Pole (SP, 2835m) provides a unique opportunity to study changes in gene expression related to the body's adaptation to hypobaric hypoxia.

Methods

Venous blood was drawn at SL and after 2 d at SP in 98 subjects (age 37±9 y, 70% male). Peripheral blood mononuclear cells (PBMCs) were isolated and microarray analysis of the mRNA isolated from these cells was performed (Affymetrix HG U133 Plus 2 microarray chip). Analysis and the computation of expression fold changes and phenotypic regression were performed using the Bioconductor package in R. Pathway analysis was performed using MetaCore™.

Results

~3200 probe sets with sig. p‐values (p<0.05) and fold changes for each subject were used in a binary logistic regression with the presence or absence of AMS during the 2 d at altitude. Corresponding p‐values and z‐values were entered into MetaCore™ for pathways analysis. Identified pathways included smooth muscle contraction, calcium signaling, and acetylcholine regulation of nerve impulses.

Conclusions

Probe sets associated with the presence of AMS had a significant representation in pathways involving aspects of the autonomic nervous system including smooth muscle contraction and nerve signaling. NSF B‐179‐M.
Arachidonic acid stimulates avian intrapulmonary chemoreceptor (IPC) discharge
Authors: Petelle Kristin M. , Migdalene Jaime A. , Hempleman Steven C.
Published: June 2021

Bronchial inflammation initiated by noxious agents or disease can affect the rate and depth of breathing by activating pulmonary afferents in mammals. To investigate this in birds, the inflammatory intermediate arachidonic acid (AA) was injected intravenously into pentobarbital‐anesthetized, ventilated ducks (Anas platyrhynchos, n=11) and cycle‐triggered stimulus histograms of IPC action potential discharge to CO2 stimulus steps were recorded. IPC discharge with 2 mg/kg AA was unchanged from vehicle control, but 8 and 20 mg/kg AA significantly stimulated mean IPC discharge and reduced phasic adaptation (ANOVA, p<0.05). AA effects were not altered by pretreatment with indomethacin (5 mg/kg, n=3). Interpretation: if inhaled noxious agents liberate AA in bird lungs, IPC discharge could be increased, which would decrease VT and increase fR, limiting further inhalation exposure. Support: NIH R15 HL087269‐02.
Theoretical estimates of lung diffusing capacity
Authors: Roy Tuhin K , Secomb Timothy W
Published: June 2021

The process of pulmonary oxygen uptake is analyzed to obtain quantitative estimates of pulmonary diffusing capacity. An axisymmetric model is used to represent radial diffusion of oxygen from alveoli through the alveolar‐capillary membrane, through the plasma, and into the erythrocytes. Analysis of unsteady diffusion due to the passage of the discrete erythrocytes shows that the transport of oxygen through the alveolar‐capillary membrane occurs mainly in the regions adjacent to erythrocytes, and that oxygen transport through regions adjacent to plasma gaps can be neglected. Calculations are performed for a range of discharge hematocrit and capillary diameter values. A value of approximately 75 mlO2 mmHg−1 min−1 is obtained for normal hematocrit, assuming a capillary diameter of 6.75 μm. This value is much lower than the estimates obtained previously by the morphometric method, which considers the total membrane area and the specific uptake rate of erythrocytes. Simulations of pulmonary oxygen uptake based on the new estimates of lung diffusing capacity are consistent with experimental data on oxygen uptake in exercise and hypoxia. Supported by NIH grant HL070657.
Simulation of expired nitrogen (N2) after inhaling and exhaling fast a non‐N2 gas
Authors: Cruz Julio Cesar
Published: June 2021

We don't know how much N2 is in the alveoli at the end of any expiration. The past April, expired N2 was presented after inhaling fast 1.9L of 79% Ar in O2 and exhaled fast (Cruz. FASEB J. 26:1082.3, 2012). Now, an attempt is made in simulating expired N2 after O2 inhalation from RV (1.4L) or FRC (4.L). The subject has a TLC=7.8L and a VC=6.4L. The model uses a VD=0.35L that is distributed from 0.018L at the apex, to 0.082L at the base of the lung. A N2=0.8 was assumed at RV or FRC. The model published (Cruz, Respir. Physiol. 86:1, 1991) has been improved by introducing the time variable to the exponential equation. Thus, the alveolar N2 fractions are now functions of lung volume and time. After exhaling to FRC or RV, 3.8L or 6.4L of O2 were inhaled in 2s and exhaled in 3s. The total expired N2 at FRC was 2.501L and at RV was 0.854L. The difference, 1.647, is exactly what would be exhaled if the total 2.08L of N2, present in the ERV, was diluted by O2. For clarity, only the classic maneuver is presented, which was executed fast to decrease the effect of alveolar gas diffusion and to avoid the cardiogenic oscillations during expiration (see Figure). The area under the expired curve was 0.854L and what remained at RV was 0.266, the balance of total N2 present at RV, prior to O2 inhalation. Remember that the curve is produced by the weighted average of uneven flows coming out from apex to base of the lung. Also, note the presence of Phase IV.

Supported in part by Center of Teaching, Research and Services (CEIS).
Modeling the N2 expirogram obtained with a normal breath and with a forced maneuver
Authors: Caucha Luis Jhony , Cruz Julio Cesar , Melendrez Jose Maria
Published: June 2021

We recently showed that the expired CO2, previously diluted in the alveoli, became more evident with the forced expiration and revealed the effect of alveolar CO2 diffusion from RV to ERV (Caucha's et al. FASEB J. 24:1063.5, 2012). Now, we modified Caucha's model to simulate a N2 expirogram, changing the number of Weibel's generations assigned for convection, convection‐diffusion and diffusion in the seven parallel regions from apex to base of the lung. The subject inhaled 1L of air from Functional Residual Capacity (FRC) and used 2.8s to exhale to FRC. The next breath, he inhaled 1L of 6.45% Ar, 72% N2 in O2 using 0.75s to inhale from FRC and exhaled to Residual Volume (RV) in 3.75s. The dotted lines are the experimental curves, and the ones obtained with the model, continuous lines, are shown in the Figure. The pulmonary blood flow was distributed exponentially from the 17th to 23rd generation; and the regional dead spaces were distributed with linear and exponential functions for the normal and force maneuver, respectively. While the number of generations for convection, convection‐diffusion and diffusion are constant for the seven parallel regions in a normal breath, in the force maneuver, the number of generations decreased for convection and increased for diffusion, from base to apex of the lung. In conclusion, the dilution of N2 is produced more at the base than at the apical regions of the lung, as a consequence of the uneven regional volume distribution during inhalation and exhalation.

Supported in part by CEIS (Centro de Enseñanza, Investigación y Servicios).
NFAT5 attenuates damage in the thick ascending limb (TAL)
Authors: Hao shoujin , Lou Hongxiang , Darzynkiewicz Zbigniew , Ferreri Nicholas R.
Published: June 2021

We previously showed that NFAT5 and NFAT1 are the major NFAT isoforms expressed in the TAL. A role for these isoforms in the response of the TAL to hypertonic‐ or hypoxia‐induced injury has not been clearly defined. Analysis by qRT‐PCR showed that the relative abundance of NFAT5 mRNA increased approximately two‐fold (p<0.05) in outer medulla when mice were given 1% NaCl in the drinking water for 3 days; NFAT1 mRNA accumulation did not change. NFAT5 protein expression increased in mTAL cells exposed to high NaCl concentration (500 mosm/kg H2O), and was reduced when cells were transfected with a lentivirus construct (U6N5‐ex8) targeting NFAT5. mTAL cell viability decreased by approximately 60% when osmolality was increased from 300 to 500 mosmol/kg H2O for 48 hr. Transient transfection with an NFAT5 overexpression vector, but not empty vector, markedly improved cell viability. Conversely, the percentage of mTAL cells undergoing apoptosis after exposure to high NaCl for 48 hr increased more than 2‐fold when NFAT5 was knocked down by U6N5‐ex8. Increases in NFAT5 and NFAT1 were observed in TAL tubules after ischemic reperfusion injury. However, shRNA knockdown of NFAT5, but not NFAT1, increased the levels of NGAL and Kim‐1, markers of renal damage. Collectively, the data suggest that NFAT5 is part of an adaptive mechanism that protects the TAL from damage due to hypertonic stress, and also may limit damage induced by hypoxia.
Maternal obesity exaggerates insulitis in female NOD offspring mice
Authors: Wang Hui , Xue Yansong , Wang Baolin , Zhao Junxing , Yan Xu , Huang Yan , Du Min , Zhu Mei‐Jun
Published: June 2021

Background

Accompanying dramatic increase in obesity, the incidence of type I diabetes (T1D) is rapidly increasing. The objective of this study is to explore impacts of maternal obesity (MO) on the incidence of T1D in female offspring using non‐obese diabetic (NOD) mice.

Methods

4‐wk‐old female NOD mice were randomly separated into two groups and fed a control or a high fat diet for 8 weeks before mating. Mice were maintained at their respective diets during pregnancy and lactation. All offspring were fed the control diet after weaning till necropsy at age of 16 weeks.

Results

Female offspring (16wk‐old) born to obese dams showed increased body weight and respiratory exchange ratio, more severe islet lymphocytes infiltration (insulitis), accompanied with elevated p65 inflammatory signaling and TNFá protein in pancreas. In addition, MO resulted in impaired glucose tolerance and low serum insulin level in offspring, which was associated with increased phos‐AMPK and phos‐ACC.

Conclusion

MO resulted in exacerbated insulitis and inflammation in pancreas of NOD offspring mice, accompanied with impaired glucose intolerance and decreased insulin level. For the first time, data show that MO negatively impacts incidence of T1D in offspring, providing a possible explanation for the increased incidence of T1D in children. NIH 1R15HD073864; INBRE P20RR016474; USDA 2008–35203‐19084; 2009–65203‐05716
Postnatal development of mononuclear phagocytes in the mouse epididymis
Authors: Grigoryeva Lubov , Hill Eric , Da Silva Nicolas
Published: June 2021

The epithelium lining the epididymis (site of sperm maturation and storage) is surrounded by mononuclear phagocytes (MPs, expressing dendritic cell and macrophage markers) that closely interact with adjacent epithelial cells. We mapped here their distribution during postnatal development in CD11c‐EYFP and CX3CR1‐GFP mice. MPs were present in the epididymis as early as 1 week after birth. The number of epididymal MPs gradually increased and, between week 4 and week 5 (puberty), they underwent major morphological changes. MPs progressively acquired a stellate/dendriform morphology and relocated from the interstitium to the peritubular region. Cellular bodies and lateral extensions were located at the base of the epithelium, while, in the initial segment, slender dendrites extended between epithelial cells towards the lumen. At week 5, MPs had acquired the overall appearance that we described previously in adult mice. In contrast, the peritubular region of the vas deferens (VD) was heavily populated by MPs during the early stages of postnatal development, long before puberty, possibly to prevent ascending pathogens from infecting the developing epididymis and testis. Our data will help better understanding the complex relationships between the immune and reproductive systems during development of the excurrent duct.

Supported by NIH‐NICHD grant 1R01HD069623.
Estrogen and hypoxia regulate expression of vascular endothelial growth factor and its receptors in uterine cervix of mice, which are localized in multiple cells of the tissue in mice and human
Authors: Zhao Susan , Ohashi Takako , Anumba Dilly , Mowa Chishimba Nathan
Published: June 2021

We have previously demonstrated the existence and profile of VEGF and its receptors, Flt‐1 and KDR, in the uterine cervix of rodents and deciphered the genome‐wide genes it regulates; and more recently examined some of VEGF's roles in uterine cervical remodeling. In the present study, we examined the effects of hypoxia and estrogen on the expression pattern of VEGF and its receptors, and mapped their cellular expression in the uterine cervix of mice and human. Ovariectomized mice were treated dose‐dependently with either 17β‐estradiol (E2) or cobalt chloride (CoCl2), to mimic hypoxia. Both human and mice sections were stained with H&E and protein expression of VEGF and its receptors were performed using confocal immunofluorescence. Also, mice tissues were analyzed for gene and protein expressions using real time PCR and Western blot, respectively. VEGF and its receptors were localized in epithelial and stromal cells in both species. VEGF and Flt‐1 expression were up‐regulated dose dependently by E2, while KDR was down‐regulated (p<0.05). VEGF and KDR were up‐regulated by 30 minutes post CoCl2 treatment, while Flt‐1 was up‐regulated at 1h post treatment. We conclude that VEGF and its receptors are present and variably expressed in the uterine cervix of women and mice; their expression in mice is altered by hypoxia and estrogen dose‐dependently. Funding: Office of students Research, Appalachian State.
Profile of hypoxia inducible factor 1 alpha [HIF‐1a], vascular endothelial growth factor [VEGF], and its receptors in the postpartum uterine cervix of mice
Authors: Fike Molly , Stanley Robert , Jesmin Subrina , Mowa Chishimba
Published: June 2021

The uterine cervix undergoes pronounced changes prior to term (pre‐partum) for a timely passage of the fetus, and also marked changes immediately after term or birth (post‐partum=pp) to enhance tissue repair in order to restore the tissue to its nonpregnant state. Because the vasculature plays a vital role in wound repair, it likely plays a similar function in pp uterine cervical repair, and since vascular endothelial growth factor (VEGF) is the key architect of vascular events and hypoxia‐inducible factor 1α (HIF‐1α) is the most potent transcription factor of VEGF, we examined the profile of HIF‐1α, VEGF, and VEGF receptors in the pp uterine cervix using timed‐pregnant (day 10) mice (C57BL6/129SvEv) allowed to undergo normal gestation and labor. Tissues (n=3) were harvested at an interval of 8hr, beginning with the emergence of the first pup (0hrs pp) to 48hrs pp, and analyzed for presence and quantity of HIF1‐α and VEGF and its receptors, Flt‐1 & KDR, using qRT‐PCR, Western blot and immunofluorescence. All molecules were found to be readily expressed during the initial part of pp, but declined by 2 days pp, relative to 0hrs pp. We conclude that HIF‐1α, VEGF, Flt‐1 and KDR likely play crucial roles in the wound healing of the pp uterine cervix. Studies to elucidate the potential mechanism underlying the actions of these molecules are ongoing.

Funding: Office of Student Research, Appalachian State University.