bluuebunny/crossref_metadata_2025 huggingface dataset:
Orexin A in the ventrolateral preoptic area promotes wakefulness and physical activity in rodents
Authors: Teske Jennifer A.
Published: June 2021

The ventrolateral preoptic area (VLPO) is critically involved in sleep regulation, receives dense orexin innervation and contains orexin receptor mRNA. Thus orexin communication in the VLPO may modulate sleep and other behaviors influencing body weight. Therefore the objective was to determine the effect of orexin A (OXA) in VLPO on sleep/wake and physical activity. The hypothesis was that OXA in VLPO would promote wakefulness and physical activity. To test this, rats were prepared with a cannula aimed at the VLPO and EEG/EMG electrodes for recording sleep/wake by radiotelemetry. EEG/EMG and physical activity from EMG in neck musculature were recorded after OXA (62.5, 125, 250, 500 pmol) or vehicle infusion. EEG/EMG data were manually scored to determine time spent in sleep/wake states (active and quiet wake; REM and slow wave sleep (SWS)). Orexin A in VLPO significantly increased time spent in active wake and physical activity counts and reduced time spent in SWS and REM sleep relative to vehicle (P < .0005). There was no effect of OXA on quiet wake. These data highlight VLPO as an integrative brain site that may be therapeutically significant for weight gain associated with abnormal sleep.
Effects of carbaryl and malathion on locomotor activity and nervous system development in zebrafish
Authors: Dunn Eric , Furimsky Marosh
Published: June 2021

Today, less than 1% of compounds that are registered for commercial use with the United States Environmental Protection Agency (EPA) have associated developmental neurotoxicity data. There is a need to identify human developmental neurotoxins and prioritize them for future studies. Two chemicals for which there is little neurotoxicity data are the insecticides carbaryl and malathion, that are commonly used in modern agriculture. Despite their benefits to agricultural yield, overspray and runoff of insecticides from fields may contaminate bodies of water, resulting in serious damage to non‐target aquatic fish. In this study, the toxicity of these two insecticides was measured by examining zebrafish locomotor activity and nervous system development, specifically the retino‐tectal area of the brain. Since both of these insecticides are acetylcholinesterase (AChE) inhibitors, it is expected that carbaryl and malathion will decrease locomotor activity and decrease the retino‐tectal area. Results indicate that carbaryl concentrations decreased swimming speed, but malathion concentrations had no effect on swimming speed. The experimental concentrations of carbaryl and malathion in this experiment can show disruptions of the nervous system by decreasing swim speed, and decreasing the retino‐tectal area. Funding for this research project was provided by the Westminster College Drinko Center.
Effect of Angiotensin on TRPV4 expression and TRPV4 agonist induced calcium transients in Hypothalamic cell line 4B
Authors: Saxena Ashwini , Nedungadi Thekkethil Prashant , Bachelor Martha , Carreno Flavia R , Cunningham J. Thomas
Published: June 2021

We have previously demonstrated that in bile duct ligated rats, an animal model of inappropriate vasopressin (AVP) release, TRPV4 protein expression and membrane trafficking is increased in AVP neurons and correlated with circulating angiotensin II (Ang II). Here, we used an in vitro approach with an immortalized AVP expressing cell line (4B cells) to investigate the possible regulation of TRPV4 by Ang II. We have characterized, for the first time, the presence of TRPV4 mRNA and protein 4B cells. After Ang II (1μM;1 hr) treatment, TRPV4 mRNA increased nearly 5‐fold (Control vs. Ang II; 1.12±0.28 vs. 4.98±0.65; p<0.001). Western Blot analysis showed significantly (p<0.001) increased TRPV4 levels in crude membrane fractions of Ang II treated cells compared to vehicle controls. Also, WB analysis revealed increased tyrosine phosphorylation of TRPV4 following Ang II treatment as compared to vehicle treated cells (p<0.001). In addition, calcium imaging experiments using Fura‐2AM dye demonstrated a significant increase in the magnitude of calcium transients elicited by theTRPV4 agonist, GSK1016790A (0.1nM, p<0.05) after 1hr incubation in Ang II. Thus, 4B cells may be an appropriate in vitro model to investigate the translational and posttranslational regulation of TRPV4 in hypothalamic neurons. R01 HL062569 & P01 HL88052
Differential regulation of TRPC4 expression in the magnocellular PVN and SON by hyperosmotic and hypoosmotic stress
Authors: Nedungadi T. Prashant , Niu Xinying , Cunningham J. Thomas
Published: June 2021

Canonical Transient Receptor Potential Channel 4 (TRPC4) is expressed in the mammalian brain and has been implicated in dendritic neurotransmitter release. Our earlier reports have shown that TRPC4 is also expressed in the vasopressin (AVP) cells of the magnocellular (MNC) supraoptic nucleus (SON) and paraventricular nucleus (PVN). To investigate whether TRPC4 expression is regulated by changes in plasma osmolality, we utilized 2 models of osmotic stress ‐ bile duct ligation (BDL) induced hypoosmolality and water deprivation (WD) induced hyperosmolality. Immunoflourescent (IF) labeled TRPC4 positive cells in the SON was significantly increased after BDL (BDL 87 ± 8; SHAM 63 ± 5) and double IF for TRPC4 and AVP showed increased colocalization in the SON (BDL SON 56 ± 6; SHAM SON 36 ± 5). However, BDL did not influence TRPC4 IF in PVN. In contrast, WD did not change the number of TRPC4 IF cells in either SON or PVN. Laser capture microdissection (LCM) of 7–10 quick immunolabeled AVP neurons for RT‐PCR showed elevated TRPC4 mRNA in the SON of BDL rats, but not in the PVN (BDL 5.3 ± 1; SHAM 1.3 ± 0.6). WD reduced TRPC4 mRNA in SON and increased in PVN. Western blot analysis showed no changes in TRPC4 in either PVN or SON of WD rats, but showed increased TRPC4 in the SON but not PVN of BDL rats (BDL 3 ± 0.4; SHAM 1.8 ± 0.1). These results show that TRPC4 is differentially regulated by hypo and hyper osmotic stress in SON but not PVN. R01 HL062579.
Intra‐vital FRET imaging reveals enhanced sympathetic arterial tone in angiotensin II‐infused biosensor mice
Authors: Wang Youhua , Chen Ling , Wier Withrow Gil , Zhang Jin
Published: June 2021

The aim of this study was to determine whether or not chronic angiotensin II (Ang II) infusion evokes conduit artery constriction in vivo, and if so, what mechanisms are involved. Ang II (400 ng/kg/min) or saline (vehicle control) was continuously infused for 2–3 weeks by subcutaneous implanted osmotic mini‐pumps in mice that expressed a FRET‐based Ca2+/Calmodulin biosensor in smooth muscle. Arterial blood pressure (BP), measured under isoflurane anesthesia, was significantly elevated in Ang II‐infused mice. Mid‐thigh femoral arteries (FA) were exposed for intravital FRET imaging and measurement of diameter. FA of Ang II‐infused mice had decreased diameter (i.e. increased ‘tone’), increased cytoplasmic [Ca2+] and dilated more after block of autonomic ganglionic transmission with iv infusion of hexamethonium, compared to FA of control mice. This suggests that FA tone is primarily maintained by sympathetic nerve activity (SNA), and that SNA was markedly enhanced by chronic Ang II‐infusion. Local block of α adrenoceptors (prazosin, 100 nM) caused significantly more reduction in tone and [Ca2+] in Ang II group than in vehicle group. Dose‐dependent vasoconstriction induced by an α adrenoceptor agonist, phenylephrine was similar, but acute local administration of Ang II‐induced vasoconstriction was reduced in chronic Ang II‐infused mice, compared to control (suggesting a possible down‐regulation of Ang II receptors). In summary, FA of Ang II infused mice have increased adrenergic tone and increased cytoplasmic [Ca2+], both of which likely result from increased SNA. Supported by AHA SDG0735461N, NIH R01 HL107654 to JZ and NIH R01 HL091969 to WGW.
SYMPATHOVAGAL IMBALANCE IN TAKOTSUBO CARDIOMYOPATHY
Authors: Norcliffe‐Kaufmann Lucy J , Kaufmann Horacio , Martinez Jose , Reynolds Harmony
Published: June 2021

Takotsubo cardiomyopathy is an acute reversible cardiac dysfunction syndrome associated with high circulating catecholamine levels. Our objective was to investigate whether abnormal cardiovascular control might play a role in the pathophysiology.

We studied autonomic cardiovascular reflexes in 10 women who had takotsubo (33±7 months after being hospitalized) and 10 age/BMI matched healthy women.

In the women with takotsubo, indices of vagal modulation of heart rate induced by respiration were uniformly reduced (expiratory:inspiratory ratio: p<0.01, pnn50%: p<0.02, rMSSD: p<0.03). Cognitive (stroop test: p<0.03) and emotional arousal (event recall: p<0.05) produced exaggerated pressor responses, without detectable ECG changes. Pressor responses to hemodynamic stimuli were also amplified (Valsalva SBP overshoot: p<0.05). Takotsubo women had increased BP variability in the short‐term (St. Dev. SBP: p<0.01). Ambulatory recordings captured an exaggerated morning surge in SBP after awakening from sleep (p<0.05). Cardiovagal baroreflex gain was significantly lower in the takotsubo women (sequence analysis: p<0.01, regression method: p<0.001, transfer function gain: p<0.001).

Women with takotsubo have heightened sympathetic responsiveness, labile BP and reduced vagal modulation of the heart. This shift in sympathovagal balance could play a role in the pathophysiology.
The lipid peroxidation end‐product and oxidant 4‐ hydroxynonenal causes insulin resistance in rat slow‐twitch skeletal muscle in vitro
Authors: Henriksen Erik John , Prasannarong Mujalin , Santos Fernando Reyes , Giovannini Franchesca Jo
Published: June 2021

The impact of the lipid peroxidation end‐product, reactive aldehyde, and oxidant 4‐hydroxynonenal (4‐HNE) on the glucose transport system in rat slow‐twitch skeletal muscle is currently unknown. Therefore, we assessed the effect of 4‐HNE on insulin signaling (IRS proteins and phosphorylation of Akt Ser473 (pAkt) and AS160 Thr642 (pAS160)) and glucose transport in slow‐twitch muscle. Soleus strips from lean Zucker rats were incubated with 4‐ HNE (50 μM) for up to 6 hr. Insulin‐stimulated (5 mU/ml) glucose transport was decreased by 4‐HNE at 2 hr (30%), 4 hr (26%), and 6 hr (39%) (p<0.05). At 2 hr of 4‐HNE treatment with insulin, pAS160 was decreased by 28%, whereas pAkt was only reduced by 11% and IRS‐1 protein was not changed. At 4 hr, pAS160 and pAkt were decreased by 22% and IRS‐1 was 39% lower. At 6 hr, pAS160 was 47% lower, pAkt was decreased by 26%, and IRS‐1 protein was reduced by 51%. Interestingly, IRS‐2 was slightly decreased (17%) only at 6 hr. These data indicate that the lipid peroxidation end‐product and oxidant 4‐HNE induces insulin resistance of glucose transport activity in rat slow‐twitch skeletal muscle, associated initially with impaired AS160 phosphorylation and subsequently with impaired Akt phosphorylation and selective loss of IRS‐1 protein. These results provide further support for an important role of lipid‐derived oxidative stress in the etiology of skeletal muscle insulin resistance.
Chronic ETA receptor blockade prevents the progression of renal injury in diabetic Dahl salt‐sensitive (SS) rats
Authors: Spires Denisha , Slaughter Tiffani , Taylor Lateia , Kojima Naoki , Williams Jan M
Published: June 2021

The endothelin (ET) system has been shown to play an important role in the development and progression of diabetic nephropathy (DN) via an ETA receptor mediated inflammatory response. Tumor necrosis factor‐alpha (TNF‐α) is inflammatory cytokine that has been used as a marker of chronic renal disease. Preliminary studies from our laboratory indicate that the induction of diabetes in Dahl salt‐sensitive (SS) rats promotes the development DN that was associated with an increase in ET‐1 excretion. Therefore, the present study examined whether chronic ETA blockade with ABT‐627 prevents the progression of renal injury in diabetic SS rats with pre‐existing renal disease by decreasing renal TNF‐α levels. After 3 weeks of diabetes (STZ, 50 mg/kg, i.p.), proteinuria increased to 375±74 mg/day. The rats were then separated into two groups: (1) vehicle and (2) ABT‐627 (5mg/kg/day). After 6 weeks of ABT‐627 treatment, proteinuria was markedly decreased in diabetic SS rats versus vehicle treated rats without any changes in arterial pressure (289±17 vs. 371±30 mg/day, respectively). The expression of the TNF‐α signaling pathway in the renal cortex was significantly reduced in ABT‐627‐ treated diabetic SS rats compared to the values observed in vehicle treated rats. These findings indicate that the prevention of progressive proteinuria with chronic ETA blockade was associated with a decrease in the renal TNF‐α pathway.
ERα66 contributes to early diabetic renal disease in mice
Authors: Irsik Debra Lima , Fallet Rachel W. , Adun Ese , Chavez Erin , Brooks Heddwen L. , Carmines Pamela K. , Lane Pascale H.
Published: June 2021

Estrogen influences the development of type 1 diabetes (T1D), but its role in diabetic renal disease is unknown. Because the kidney expresses the full‐length estrogen receptor (ERα66), its ERα36 splice variant, and ERβ, we hypothesized that ER protein levels impact renal structure and function during T1D. T1D was induced by streptozotocin (STZ) injection in 8‐wk‐old C57/Bl6 mice that are null for ERα66 but still express ERα splice variants (ERα66KO) and their wild‐type (WT) littermates. Nondiabetic (sham) mice received STZ vehicle injection. Six weeks later, glomerular area was greater in STZ‐WT (3285±223 μm2) than in sham‐WT (2212±96 μm2; P<0.05), but did not differ between sham‐ and STZ‐ERα66KO (2386±91 and 2378±62 μm2, respectively). Renal F4/80+ staining was greater in STZ‐WT than in sham‐WT (0.76±0.08 vs 0.32±0.09 AU/area; P<0.05), and did not differ between sham‐ and STZ‐ERα66KO. Renal cortical ERα36 protein levels in STZ‐WT averaged 66% of sham‐WT (P< 0.05), but did not differ between Sham‐ and STZ‐ERα66KO. Renal ERβ levels were similar in all groups. Phosphorylated‐to‐total ERK1/2 was increased 2.5‐fold in the renal cortex of STZ‐treated mice regardless of genotype (P< 0.05). Thus, although ERα is not implicated in the T1D‐induced renal cortical ERK activation, ERα66KO protects against the glomerular enlargement (an early marker of nephropathy) and renal macrophage infiltration accompanying T1D.
Changes in levels of mitochondrial nitric oxide in diabetic rats treated with Eryngium carlinae
Authors: Noriega‐Cisneros Ruth , Arellano‐Plaza Melchor , Esquivel‐Gutiérrez Edgar , Cortés‐Rojo Christian , Manzo‐Avalos Salvador , Salgado‐Garciglia Rafael , Saavedra‐Molina Alfredo
Published: June 2021

Diabetic nephropathy is an important microvascular complication and is the major cause of end‐stage kidney disease. E. carlinae is a plant used by diabetic patients to treat complications of this disease, which have been attributed diuretic and anti‐inflammatory properties. This study was conducted to explore changes in stress oxidative and antioxidant activity in mitochondria of kidney of diabetic rats treated with E. carlinae. Were realized measurements of thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), dismutase superoxide (SOD) and catalase (CAT) activity. The results show an increase in NO levels and SOD activity and CAT. Treatment with E. carlinae not modify the activity of the antioxidant enzymes but decreased levels of NO, which could be related to a decrease in the progression of renal disease as it has been reported that there is an elevation of NO in early stages of the disease.
Dot1a Functions as a Novel Renoprotective Factor by Repressing Endothelin 1 in Diabetic Mice
Authors: Chen lihe , Wu Hongyu , Zhou Qiaoling , Zhang Wenzheng
Published: June 2021

Our goal is to determine if aldosterone‐downregulated histone H3 K79 methyltransferase Dot1a represses endothelin 1 (ET1) and thus has a renoprotective role in diabetic mice. We used our Dot1lAC mice that lack Dot1l and thus Dot1a specifically in Aqp2+ cells, as the model system. After induction of diabetes with Streptozotocin for three months, diabetic Dot1lAC mice vs. control had more prominent features mimicking human chronic kidney disease (CKD), which was associated with increased ET1 expression. The CKD features include proteinuria, extreme polyuria, natriuresis, interstitial fibrosis, mononuclear cell infiltrate, and various tubular abnormalities (dilated lumen, epithelial thinning, nuclear irregularity, eosinophilic cytoplasm, and severe tubular basement membrane thickening). Administration of ET1 inhibitors ameliorates the kidney injury and function. Therefore, our study for the first time linked aldosterone to kidney injury through Dot1a and ET1, identified a novel role of Dot1a in renal protection possibly by repressing ET1, established diabetic Dot1lAC as a novel mouse model for CKD, and reinforces the notion that blocking ET1 as a potential therapeutic strategy for CKD.
The Anandamide Cyclooxygenase‐2 Metabolite, Prostamide E2, as a Novel Diuretic and Natriuretic Lipid in the Mouse Renal Medulla
Authors: Ritter Joseph K , Li Cao , Xia Min , Boini Krishna M. , Lichtman Aron H. , Li Pin‐Lan
Published: June 2021

Anandamide (AEA) is an arachidonate derivative found at high levels in the kidney, but its physiological roles in the regulation of renal function are not yet well understood. In anesthetized mice, AEA infused into the renal medulla (15–60 nmol/kg/min) increased urine volume and sodium excretion. These effects were blocked by intravenous celecoxib (0.1 μg/kg/min), suggesting a role for a COX‐2 metabolite of AEA. In agreement with this hypothesis, intramedullary infusion of prostamide E2 (PE2), the major prostamide formed by mouse kidney homogenates incubated with AEA, increased urine formation and sodium excretion in a dose‐dependent manner. Furthermore, both AEA and PE2 were found to enhance the pressure natriuresis. Compared with control mice, AEA or PE2 doubled the natriuretic response when renal perfusion pressure was elevated from 95 to 125 mmHg, and AEA‐induced enhancement of pressure‐natriuresis was blocked by celecoxib. More mechanistic studies revealed that the PE2‐induced diuresis and natriuresis were substantially blunted when these mice were pretreated with hydrochlorothiazide, but not with furosemide or amiloride. These results suggest that PE2 is a novel natriuretic lipid that may act on the distal tubules to inhibit sodium reabsorption and that its enhancing action on pressure‐natriuresis may represent an important renal medullary antihypertensive mechanism. Supported by NIH grants DK54927 and DA009789.
COX‐2 induction is ROS dependent in rats during 3 days unilateral ureteral obstruction
Authors: Østergaard Martin , Nilsson Line , Frøkiær Jørgen , Nørregaard Rikke
Published: June 2021

Oxidative stress may contribute to cellular dysfunction of the kidney with unilateral ureteral obstruction (UUO). Previously we have shown induction of cyclooxygenase type 2 (COX‐2) in renal medullary interstitial cells (RMIC) during UUO. This study investigated the role of oxidative stress or ROS in the induction of COX‐2 during UUO.

Rats were subjected to 3dUUO and treated with inhibitors of the ROS production (NADPH‐oxidase inhibitor diphenylene iodonium (DPI) and the complex‐1 inhibitor rotenone (ROT)). Clearance experiments were performed. The kidneys were removed and prepared for immunoblotting or immunohistochemistry (IHC) analyses.

Bodyweight (BW) was unchanged in 3dUUO rats subjected to DPI whereas ROT decreases BW. Hematoxylin and eosin (HE) staining of the kidney showed lower degree of dilatation due to DPI or ROT treatment in 3dUUO rats. COX‐2 and the oxidative stress marker heme‐oxygenase type 1 (HO‐1) was both increased in inner medulla in response to 3dUUO. This was attenuated by DPI or ROT administration. IHC confirmed these findings. COX‐1 was not changed in 3dUUO rats subjected to DPI or ROT. Plasma urea was not affected by DPI or ROT treatment in response to 3dUUO. HE staining of heart, liver, and brain did not reveal any obvious changes due to administration of DPI or ROT.

These results suggest that oxidative stress contribute to the regulation of COX‐2 in inner medulla in rats subjected to 3 days UUO.
Renal toxicity of domoic acid
Authors: Funk Jason A , Janech Michael G , Steele Stacy L , Dillon Joshua C , Bell P Darwin
Published: June 2021

Domoic acid (DA) is a glutamate analog and a characterized neurotoxicant. Outside of the CNS, glutamate receptors are also found in peripheral tissues, including the kidney, which opens the possibility that the kidney may also be susceptible to excitatory toxicity. When mice were injected with DA (2.5 mg/kg, i.p.), and euthanized between 30 min and 2 hr after injection, DA concentrations were approximately four‐fold higher in the kidney than any other tissue examined. Probenecid co‐administration (600 mg/kg) further augmented concentrations in the serum, kidney, heart and hippocampus, highlighting organic anion transporters in the renal clearance of DA. To determine nephrotoxicity, mice were injected with DA (0.25–2.5 mg/kg), a range below that which elicits overt neurotoxic effects, for three consecutive days. No change in serum creatinine was observed; however, urinary NGAL was elevated within 24 hr, and urinary kidney injury molecule‐1 (uKim‐1) was elevated 72 hr after initial dose. Tissue analysis also showed elevated NGAL and Kim‐1 protein in the kidneys of mice exposed to DA. Additionally, fluorescent imaging revealed alterations in aquaporin‐2 and Na+,K+‐ATPase localization in medullary collecting ducts. Finally, when DA was administered after a 12 hr dehydration period, uKim‐1 was increased compared to DA alone, suggesting water restriction exacerbated kidney injury. Overall the data indicate that DA is preferentially distributed to the kidneys, clearance is dependent upon organic anion transport, and renal toxicity occurs within a concentration range below what is known to elicit neurotoxicity. JAF is supported by the training grant 5T32DK007752–14 (NIDDK/NIH).
Sulfur Dioxide Derivative Prevents Left Ventricular Hypertrophy and Electrophysiological Alterations
Authors: YARAÞ Nazmi , Özdemir Semir , Dalaman Uđur , Öztürk Nihal , Olgar Yusuf
Published: June 2021

SO2and derivatives generally accepted as toxic gasseous molecules and inhalation of itdrives biological systems severe conditions. On the other hand, they are used as safepreservative in foods. Recently, SO2was discovered to be produced in thecardiovascular system and to influence important biological processes.

It was reported by Liang Y.et al that endogenous SO2progressively inhibit hypertrophycaused by isoproterenol application to rats via increasing antioxidation capacity. In this study we aimed to investigate underlying molecular and electro physiological mechanisms of this inhibition of ventricular hypertrophy. Wistar rats were administrated 20 mg/kg isoproterenolfor seven days subcutaneuosly to drive hypertropic cardiomyopathy and some animals was taken SO2 donor sodium metabisulfite together with isoproterenol through i.p. at a dose of 85 mg/kg. At the end of the experiment, animals were sacrified by heart exicition and followed by enzimatic dissociation of single left ventricular myocytes. Iso admistrated animal heart (6.69±0.41 mg/kg bodyweight) were hypertrofied compared to control animals hearts(3.94±0.12 mg/kg). On the other hand, metabisulfite inhibits hypertrothy of the rats hearts (4.27±0.32 mg/kg).Single cardiomyocytes were examined electrophysiologicaly by voltage clamp in order to examine effect of SO2on potassium currents (IK1, Ito and Iss), action potential (AP) and L‐type calcium current (ICaL). While metabisulfite had no effect on potassium currents, prolonged AP and reduced ICaL ameliorate to the control level. In conclusion, SO2derivative sodium metabisulfite prevent cardiac hypertrophy generated by adrenergicstimulation both electrophysiologicaly and histologicaly. This work supported by Akdeniz University Scientific Research Unit.
Active SHP2 protects the pulmonary endothelium through a FAK‐mediated mechanism
Authors: Chichger Havovi , Duong Huetran , Braza Julie , Thompson Milanda , Grinnell Katie , Harrington Elizabeth
Published: June 2021

Enhanced protein tyrosine phosphorylation is associated with increased vascular permeability. We have previously shown that chemical and molecular inhibition of the protein tyrosine phosphatase, SHP2, promotes edema formation in the pulmonary endothelium (EC) in vitro and in vivo; thus implicating SHP2 in a protective role of pulmonary EC barrier function. To study whether this function of SHP2 translates to therapeutic value, we assessed the effect of molecular activation of SHP2 on EC barrier function in response to edemagenic agents, lipopolysaccharide (LPS) and thrombin. Both LPS and thrombin reduced SHP2 activity, which correlated with an elevation in focal adhesion kinase (FAK) Y397 phosphorylation and decrease in SHP2 protein‐protein associations with FAK, p120RasGAP, and p190RhoGAP. In contrast, the barrier protective agent S1P elevated SHP2 activity, enhanced FAK Y576 phosphorylation and increased FAK‐SHP2 association. In vivo, overexpression of constitutively active SHP2 (caSHP2) enhanced EC monolayer resistance at basal conditions and attenuated LPS and thrombin‐induced permeability, however had no effect on s1P‐induced barrier protection. In vivo, overexpression of caSHP2 completely attenuated LPS‐induced pulmonary edema formation. Our data demonstrated that the protective role for SHP2 in maintaining pulmonary EC barrier function may be mediated via FAK.
Increased Myogenic Reactivity of Resistance‐Caliber Mesenteric Arteries from Pregnant Rats with Differential Reductions in Uterine Perfusion Pressure: Impact of Thromboxane
Authors: Reho John J , Toot Jonathan D , Peck Jennifer , Novak Jacqueline , Ramirez Rolando J
Published: June 2021

Reductions in uterine perfusion pressure are central to the pathogenesis of preeclampsia and may trigger increased production of vasoconstrictor prostanoids such as thromboxane (TX). This may lead to the altered maternal vascular reactivity observed in preeclampsia. The purpose of this study is to determine the impact of TX on resistance artery vascular behavior after reductions in uterine perfusion pressure in gravid rats. Pregnant dams were subjected to periodic (Occluder) and chronic (RUPP) reductions in uterine perfusion pressure on GD 14 and compared to SHAM operated controls. On GD 21, resistance‐sized mesenteric arteries were investigated using a pressurized arteriograph where myogenic reactivity and TX constriction were analyzed. Myogenic reactivity was increased to a similar degree in mesenteric arteries from Occluder and RUPP rats compared to SHAM (p<0.05). Pretreatment of arteries with meclofenamate (non‐specific COX inhibitor) or SQ29548 (TX receptor antagonist) ameliorated the increased myogenic reactivity in Occluder and RUPP arteries (p<0.05). Vasoconstriction with U‐46619 was increased in mesenteric arteries from Occluder and RUPP compared to SHAM (p<0.05). These data provide evidence that the vasoconstrictor prostanoids such as TXA2 at least partially mediates the maternal vascular dysfunction that occurs in response to reduced uterine perfusion during pregnancy.
Blood‐brain barrier leak precedes brain histopathology and cognitive impairment in mild hyperhomocysteinemia
Authors: Rhodehouse Bryce C , Mayo Jamie N , Beard Richard S , Chen Cheng‐Hung , Bearden Shawn E
Published: June 2021

Hyperhomocysteinemia (HHcy) is associated with blood‐brain barrier (BBB) permeability and Alzheimer's disease. We explored the relation among BBB permeability, brain histopathology, amyloid‐beta (Abeta) transport and deposition and cognitive function in HHcy. We used C57Bl/6 mice with heterozygous deletion of cystathionine β‐synthase (Het) and wild‐type littermates (WT) [young: 5–9 mos; old: 12–29 mos]. BBB permeability was greater in Het compared to WT at all ages (p<0.05). Old, but not young, Het mice had greater cognitive impairment than any other group in Morris water maze tests (p<0.05). Old Het mice also showed greater inflammation (CD45+ and VCAM+) and leukoaraiosis in the fornix compared to WT (p<0.05) with concomitant evidence of disrupted autophagy in the hippocampus (increased caspase‐cleavage of beclin‐1; p<0.05). There were no differences for these measures among young or WT mice. There was no difference in levels of Abeta transporters in isolated cerebral microvessels (RAGE, LRP‐1, Pgp) or Abeta deposition in the brain with age or by Hcy level.

Conclusion

in mild HHcy, increased permeability of the BBB precedes the onset of brain histopathology and cognitive dysfunction, which is independent of Abeta deposition. Protecting the BBB from the effects of Hcy early in life may reduce the incidence or severity of cognitive decline later in life. Supported by NIH HL106548 (SEB).
Morning and Afternoon Bouts of Exercise Result in the Same Physiological Stress Response
Authors: Dautermann Valerie M , Mantina Namoonga M , Johnson Kathryn MS
Published: June 2021

Circulating cortisol levels increase in response to physiological stress beyond levels observed in normal diurnal patterns. To compare the physiological stress response after a signal bout of exercise in the morning versus the afternoon, participants were assigned to three groups: morning exercise (n=8), afternoon exercise (n=7), or no exercise (n=7). Morning and afternoon exercise groups participated in 15 minutes of training, alternating resistance and cardiovascular activities, at 07:00 or 15:00 hours, respectively. Salivary cortisol samples were taken from all participants throughout the day. Pulse and blood pressure were recorded to ensure consistency of exertion during exercise bouts. Mean peak cortisol concentrations following exercise occurred 30–45 minutes after completion of exercise (1.16 ± 0.237 μg/dL and 0.651 ± 0.177 μg/dL, morning and afternoon exercise groups, respectively). There was a significant increase in salivary cortisol levels, as indicated by increase in area under the curve (AUC), between the no exercise and the morning exercise groups (p=0.0009), with cortisol levels reaching values almost twice the magnitude in the morning exercise group. Time of day did not affect the physiological stress response to exercise, as there was no significant difference in salivary cortisol AUC. V. Dautermann and N. Mantina were supported by the Beloit College Biomedical Scholars Program.
Effects of interval exercise on lactate levels and brain oxygenation in children
Authors: Ganesan Goutham , Reuland Warren , Galassetti Pietro , Aizik Shlomit , Zaldivar Frank , Cooper Dan
Published: June 2021

Adaptation of blood flow/oxygenation dynamics in critical cerebral areas, during specific stimuli such as physical exercise, may reflect onset/progression of early vascular dysfunction. Near‐infrared spectroscopy (NIRS) has been proposed as a way of investigating this phenomenon. Time‐resolved NIRS (TRS), via characterization of absorption and scattering, allows accurate deoxy‐(Hb) and oxyhemoglobin (HbO2) quantification. Many studies have shown that PFC Hb levels, reflecting local metabolism, increase during and remain elevated after exhaustive incremental exercise, indicating a continued metabolic demand in the post‐exercise state. We now aimed to characterize prefrontal cortex (PFC) oxygenation dynamics in children during prolonged intense exercise with sustained lactate elevations, hypothesizing that PFC function would be similarly activated, with increased O2 uptake, metabolism, and [Hb]. Five children performed ten 2 min bouts of high‐intensity exercise, with 1 min rest intervals; after lactate levels reached a plateau, a gradual, linear increase in PFC [Hb] occurred, independent of fluctuations due to alternating exercise/rest (figure). This finding suggests a potential connection between circulating lactate levels and brain oxygenation, and may have implications in studies of fatigue and exercise tolerance. Supported by grants NIH HD‐48721–06A1 and 8TL1TR000148–03.
Intensity, muscle activation, and PGC‐1α expression are dissociated following supramaximal interval exercise
Authors: Foster William S , Hankinson Paul B , Edgett Brittany A , Simpson Craig A , Graham Ryan B , Gurd Brendon J
Published: June 2021

Muscle activation and the change in peroxisome proliferator‐activated receptor y co‐activator 1α (PGC‐1α) mRNA expression following high‐intensity interval exercise (HIIE) were examined in healthy men (n=8; age, 21.9 ± 2.2 yrs; VO2peak, 53.1 ± 6.4 ml/min/kg; peak WR, 317 ± 23.5 watts). Participants reported to the lab for 3 experimental visits. On each visit HIIE was performed on a cycle ergometer with a target intensity of either 73 (LO), 100 (MI), or 133% (HI) of peak WR. Muscle biopsies were taken at rest and 3 hours after each exercise condition. There were no differences in total work between conditions (~730 kJ) while average power output (LO, 237 ± 21; MI, 323 ± 26; HI, 384 ± 35 watts) and EMG derived muscle activation (LO, 1262 ± 605; MI, 2089 ± 737; HI, 3029 ± 1206 total integrated EMG per interval) increased in an intensity dependent fashion. PGC‐1α mRNA was elevated (p<0.05) after all 3 conditions, with the increase observed following MI (~9 fold) being greater (p<0.05) than that observed following both LO and HI (~4 fold). When expressed relative to muscle activation, the change in PGC‐1α for HI was less than (p<0.05) that for LO and MI. These findings suggest that intensity dependent increases in PGC‐1α mRNA following submaximal exercise are largely due to increases in muscle recruitment. Interestingly, intensity, muscle activation and PGC‐1α mRNA were dissociated following HI. This research was supported by NSERC.
Is resting diastolic dysfunction related to impaired cardiovascular reserve in the metabolic syndrome?
Authors: Fournier Sara B , Donley David A , Reger Brian L , Bonner Daniel E , Warden Bradford E , Gharib Wissam , Chantler Paul D
Published: June 2021

Metabolic Syndrome (MetS) is a cluster of cardiovascular (CV) risk factors associated with functional limitations and an increased risk of CV mortality. Resting diastolic function is thought to be altered in MetS and may contribute to increased CV risk and functional deficiency. Using echocardiography we explored the relationship between resting diastolic function and left ventricular (LV) contractile reserve capacity, assessed by the change from rest to peak exercise in end‐systolic elastance (ΔEes), in Mets (n=21) and healthy controls (n=13). MetS had resting diastolic dysfunction and a 15% decrease in ΔEes (p<0.05) vs. controls. Univariate analysis, used to examine the correlation between ΔEes and resting diastolic function revealed that ΔEes was related to LV end‐diastolic pressure (EDP), the transmitral to mitral annular early diastolic velocity ratio (E/e’), the diastolic stiffness constant (β), and the isovolumetric relaxation time constant (τ) (p<0.05). We used multivariate analysis to examine the relationship between ΔEes and diastolic function after adjusting for age and metabolic risk score (MRS: the sum of risk points selected for specific CV risk factors). After adjusting for age and MRS, ΔEes remained associated with LV EDP, E/e’, β, and τ (p<0.05), suggesting a link between resting diastolic dysfunction and altered CV reserve in metabolic disease states. AHA 11CRP7370056, 5T32HL090610–04.
Influence of the metaboreflex on arterial blood pressure in heart failure patients
Authors: Keller Manda Linea , Johnson Bruce D , Joyner Michael J , O'Malley Kathy A , Miller Andrew , Olson Thomas P
Published: June 2021

Feedback from active locomotor muscles contributes to the pressor response and may be more prominent in heart failure (HF) due to muscle myopathy, greater metabolite production and/or heightened sensitivity of receptors. We sought to examine the influence of metaboreflex stimulation on mean arterial pressure (MAP) in HF. Eleven HF patients (51±15yrs, NYHA Class I/II, LVEF 32±9%) and 11 controls (CTL) (42±9yrs) were recruited. Participants completed 3 study visits; 1) maximal cycle ergometry, 2) and 3) constant‐work cycling (60% peak power) for 4 min with 2 min recovery. Recovery was randomized to normal or regional circulatory occlusion (metaboreflex stimulation). Oxygen consumption (VO2), carbon dioxide production (VCO2), blood pressure and heart rate (HR) were measured at rest, end‐exercise and recovery. With metaboreflex stimulation, MAP and systolic blood pressure (SBP) increased in HF compared to CTL (6.8±5.8% vs −3.0±7.8%, p<0.01 and 3.4±6.4% vs −12.7±10.4%, p<0.01, respectively), with no difference in diastolic pressure (p=0.61). HR and O2 pulse demonstrated an attenuated return to baseline in HF (6.7±5.9% vs 1.0±6.6%, p<0.01 and −50.4±15.6 vs −72.4±6.9%, p<0.01, respectively). Metaboreflex stimulation resulted in a marked pressor response in HF relative to CTL due primarily to an influence of SBP and attenuated cardiac recovery as suggested by the persistent elevation in HR and O2 pulse.
EFFECT OF RESISTANCE TRAINING ON CIRCULATING Th2 CYTOKINES IN HIV+ MEN RECOVERING FROM SUBSTANCE ABUSE
Authors: Duplanty Anthony Adam , Vingren Jakob L , Curtis John H , Lee Elaine C , Budnar Ronald G , McFarlin Brian K , Hill David W
Published: June 2021

Human immunodeficiency virus (HIV) and substance abuse (drug and/or alcohol) independently impair the immune system. IL‐4 and IL‐10 are cytokines involved in B‐cell mediated adaptive responses relevant to HIV. IL‐4 suppresses the production of Th1 cells. IL‐10 increases with disease progression in HIV infected individuals and down regulates the expression of Th1 cytokines. Thus, changes in Th2 cytokines could have important implications for HIV+ individuals.

Purpose

To examine the effect of resistance training on resting concentrations of circulating Th2 cytokines.

Methods

Sixteen men (42 ± 11 years, 180 ± 9 cm, 89 ± 21 kg) infected with HIV and enrolled in a 60‐day in‐patient substance abuse treatment program. Participants were assigned to either supervised resistance exercise 3 times per week (RT) or no exercise training (Control) for six weeks. Before (Pre) and after (Post) the 6‐week period, resting and fasted blood samples were obtained and analyzed for serum IL‐4 and IL‐10.

Results

IL‐10 did not change following the 6‐week period for RT (Pre: 1.9 ± 0.3 pg·ml−1; Post: 1.8 ± 0.4 pg·ml−1) or Control (Pre: 1.6 ± 0.2 pg·ml−1; Post: 1.5 ± 0.2 pg·ml−1). IL‐4 was undetectable (<0.08 pg·ml−1) in 9 of 16 participants.

Conclusion

A six‐week resistance training program does not elicit changes in the circulating Th1 cytokines IL‐4 and IL‐10 in HIV+ men undergoing substance abuse treatment.
Angiotensin II and developmental cardiovascular‐renal interactions in embryonic chickens
Authors: Mueller Casey A , Crossley Dane A , Burggren Warren W
Published: June 2021

The role of Angiotensin II (ANGII) in cardiovascular‐renal interactions during embryonic development of White Leghorn chickens (Gallus gallus domesticus) was examined. Captopril, an angiotensin‐converting enzyme (ACE) inhibitor, or control saline, was delivered via the egg air cell on days 5–18. Masses, fluid osmolality and mean arterial pressure (MAP) and heart rate (fH) were measured on day 19 (90% of incubation). Embryo and heart masses did not differ between control and captopril embryos, but kidney wet and dry masses were both 10% larger in captopril embryos. In addition, blood osmolality was significantly lower. Captopril embryos were significantly hypotensive, with a MAP 15% lower than controls, but fH did not differ. MAP and fH of captopril embryos did not respond to an injection of Angiotensin I (ANGI), confirming ACE inhibition. ANGII induced a stronger hypertensive response in captopril embryos, with adrenergic and ganglionic blockade indicating that this was due to peripheral catecholamines. Chronic removal of embryonic ANGII has both cardiovascular and renal effects, implying “crosstalk” between the developing systems. Funding from NSF (IOS‐1025823) to WB.
Using inner opercular membranes to replace branchial epithelia for comparing the chloride permeability and cell turnovers between freshwater‐and seawater‐type ionocytes of the brackish medaka, Oryzias dancena
Authors: Kang Chao‐Kai , Lee Tsung‐Han , Hwang Pung‐Pung
Published: June 2021

Ionocytes have been observed in the inner opercular membrane (OM) of various teleosts including the brackish medaka (Oryzias dancena). The present study illustrated that the characteristics of OM were perfect for investigating the functional morphologies of freshwater (FW)‐type and seawater (SW)‐type ionocytes in this medaka species. In addition, cell turnovers of these ionocytes were determined. In the OM of the medaka transferred from SW to FW for 7days, the basolateral immunoreactive signals of Na+, K+, 2Cl− cotransporter 1a were observed as a marker for identifying the pre‐existed SW‐type ionocytes rather than the newly differentiated FW‐type ionocytes. Meanwhile, the results of silver staining on apical openings demonstrated that chloride permeability was weaker in the pre‐existed SW‐type ionocytes compared to the newly differentiated FW‐type ionocytes. In the brackish medaka, the OM is a tissue which could be easily observed and used to replace the branchial epithelia for examining the transformation between different types of the ionocytes upon osmotic challenges.
Video Microscopy Detection of Oyster Spat Heart Rate (HR): Acclimation temperature alters HR response to acute temperature change
Authors: Domnik Nicolle Jasmin , Polymeropoulos Elias T , Elliott Nick G , Frappell Peter B , Fisher John T
Published: June 2021

We developed a non‐invasive method to measure oyster spat heart rate (HR) during a cooling/warming protocol. Triploid spat (1.1–1.8mm; 3–4 months) were acclimated to 10°C (“cool”; n=5) or 22°C (“hatchery”; n=5), and exposed to a temperature ramp protocol (22°C to 10°C to 22°C; 2°C intervals, 10 minutes per set‐point). Hearts were visualized using video acquisition/image analysis, and HR identified by commercially‐available software. HR was directly related to temperature in both groups. HR at each set‐point did not vary between cooling/warming; however, “hatchery” spat displayed consistently elevated HR vs. “cool” spat. Heart rate variability (HRV) was inversely related to temperature in both groups. “Cool” spat consistently displayed elevated HRV vs. “hatchery” spat, and displayed greater HRV during cooling vs. warming. Spat also displayed periods of asystole of varying lengths, which were more prevalent and prolonged at low temperatures, (“hatchery”: 5/5 asystolic at set‐point 10°C, vs. “cool”: 1/5 asystolic at set‐point 10°C). Our method provides a robust means of assessing HR in a simple, invertebrate model. Our data suggest that the HR phenotype of commercial oyster spat is altered by different acclimation temperatures, which may be useful in understanding spat thermal adaptation and growth in ocean aquaculture environments.
Two days of staging at moderate altitude induces 65–75% of the ventilatory acclimatization achieved with two days of continuous residence at 4300 m
Authors: Staab Janet E , Beidleman Beth A , Fulco Charles S. , Grunbeck Marie R , Guerriere Katelyn , Raeburn Jennifer , Muza Stephen R
Published: June 2021

Six days of staging at 2200 m induces ventilatory acclimatization prior to exposure to 4300 m based on end‐tidal carbon dioxide (PETCO2). The impact of two days of staging on ventilatory acclimatization is unknown. Two independent groups of unacclimatized men were staged for 2 days at either 2500 m (n=12, 23±3 yr, 80±6, mean±SD) or 3000 m (n=7, 23±2, 79±6) prior to ascent to 4300 m and were compared to a control group that directly ascended and lived for 2 days at 4300 m (n=7, 21±3, 76±4). PETCO2 (mmHg) was measured in the morning at sea level (SL) and following 2 h at 4300 m in the staged groups and 48 h of continuous residence at 4300 m in the control group. The PETCO2 measured at SL was not different (P>;0.05) in the 2500 m (39.0±4.0), 3000 m (39.4±4.0) and control group (37.9±4.0). PETCO2 decreased (P<0.05) from SL to 4300 m in the 2500 m (32.8±3.2) and 3000 m (32.1±3.2) groups but the decrease in PETCO2 was greater (P<0.05) in the control group (28.2±3.2). The change in PETCO2 from SL to 4300 m in the 2500 m (6.3±2.9) and 3000 m (7.3±3.0) groups was lower (P<0.05) than the change in the control group (9.7±4.0). These results demonstrate that two days of staging at either 2500 m or 3000 m prior to exposure to 4300 m was effective in inducing 65–75% of the ventilatory acclimatization achieved with 2 days of continuous residence at 4300 m. Funding: USAMRMC. Authors’ views; not official U.S. Army or DoD policy.
Comparative responses of arterial oxygen saturation and heart rate during postnatal development in rats living at high and low altitude.
Authors: Lemoine Alexandra , Villalpando Gabriella , Gonzales Marcelino , Soria Rudy , Joseph Vincent
Published: June 2021

We used pulse oximetry to measure arterial oxygen saturation (SpO2) and heart rate (HR) in 4 and 14 day‐old rats raised at HA (La Paz, Bolivia, 3,600 m/12,000ft) or at sea level (SL, Québec, Canada). SpO2 and HR were measured at 5 different levels of inspired PO2 (PiO2: 160 ‐ 60 mmHg – 10 min each), in awake rats maintained in a chamber flushed with room air or the desired gas mixtures. When exposed to a PiO2 of 160 mmHg, P4 HA rats had a similar SpO2 than P4 SL, but a lower HR. At lower PiO2, HA rats maintained a much higher SpO2 than SL rats. HR increased in HA rats (but not in SL rats) at low PiO2. Contrastingly, P14 HA rats exposed to a PiO2 of 160 mmHg had a lower SpO2 than SL (93.7±1.1% vs. 98.8±0.1%, p<0.0001), and similar SpO2 at lower PiO2. HR was higher in P14 HA rats vs. SL rats at all PiO2 levels. A group of SL rats was raised in hypoxia (13.5% O2 – similar to HA PiO2) between P4 and P14. This reduces SpO2 values measured at PiO2 below 160 mmHg, and enhances HR. Male and female rats had similar responses. We conclude that: a) 4‐day old rats raised at HA had efficient responses that help maintaining a high SpO2 under a wide range of PiO2 ‐ b) these responses are no longer apparent in P14. Since rats are not found under natural conditions at HA, success to develop adequate responses to hypoxia during early postnatal development might be critical for genetic adaptation to altitude. Founded by NSERC.
An In Vitro Hypoxia/Reoxygenation Model of Ischemia/Reperfusion Injury with Glucose Oxidase And Catalase
Authors: Bowman Phillip , Bynum James A , McFaul Steve J
Published: June 2021

Subjecting cells to reduced oxygen (O2) by purging the atmosphere with nitrogen is a slow process that does not reproduce the rapid local reduction in oxygen that occurs in vivo following decreased oxygen availability due to ischemia. Glucose Oxidase (GOX) rapidly oxidizes glucose and when coupled with Catalase (CAT) to decompose hydrogen peroxide rapidly produces a very low oxygen level (< 0.4 μM within 5 min) as may occur during ischemic injury. To better understand the response of human cells to the rapid reduction in O2 human umbilical vein endothelial cells (HUVEC) were subjected to 0.4 μM O2 for up to three hours in complete medium containing GOX and CAT or control medium and total RNA extracted and subjected to gene expression profiling with whole genome microarrays. 368 genes were statistically altered in their expression with a false discovery rate < 10%. Most of these genes experienced down regulation. Prominent among genes down regulated was EGLN3 (hypoxia inducible factor 1A {HIF1A} prolyl hydroxylase) that accounted for the rapid rise in HIF1A detected by western blotting. Only 14 genes were upregulated more than 2‐fold. The GOX‐CAT system reliably reduces O2 levels in the pericellular media around cultured cells in a short time. This system more closely reproduces the rapid hypoxia induced by ischemia brought on by vascular occlusion or injury.