bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Freely Moving Animal Based Blood Pressure, ECG, and Dual Body Temperature Telemetry System for Group Housed Mice in Social Context
Authors: Knot Harm Johan , Lee Dexter
Published: November 2023

Traditional rodent blood pressure (BP) monitoring required single housing, a known stressor for rodents. We developed a microprocessor based long range wireless telemetry system based on the Stellar™ technology with internal memory that allows rodents to live in groups, interact, exercise and be housed in large enriched environments. BP or ECG is recorded with a solid‐state sensor along with core temperature and 3D activity. Heart rate was derived from BP and/or ECG in the Biopac AcqKnowledge 4.4.1 software.

It is well established that rodent behavior is strongly influenced by social interaction. Moreover, spontaneous hierarchies develop in group housed animals and cardiovascular parameters such as heart rate and blood pressure reflect these conditions. Since animal experimentation most notably in neuroscience and behavior studies gravitate towards group housed colonies also for sake of animal welfare new technologies are needed to allow traditional measurements to be done in these new more refined research environments. Moreover, in the case of metabolic studies where animals tend to huddle in groups when they sleep, a similar adaptive behavior needs to be taken into account when calculating energy expenditure in nutritional and diabetes/obesity studies.

In order to objectively validate this system we implanted 5 male mice of ca. 20 g. After 8 days of recovery the animals entered an exploratory study to compare fidelity and accuracy of the novel solid‐state microtipped pressure lead (450 micron) based wireless implant and BP was recorded for 10s every 15 min for 4 weeks sampled at 200Hz. The BP responses were compared to a control group of 5 animals implanted with a similar conventional implant from a competitor sampled for 5s every minute at 500Hz equiped with a fluid‐filled catheter. Mean dark phase arterial pressures (MAP) at 14 days in the Stellar group were 134 ± 31 mmHg at a Heart rate (HR) of 544 ± 67 BPM versus 127 ± 9 mmHg at a HR of 545 ± 24 in the control group. Further studies on core body temperature are progressing and will be presented.

We conclude that there are no significant differences in quantitative blood pressure responses between the Stellar digital telemetry device versus a leading analog competing device while being able to record from up to 5 different animals without cross‐talk. We also conclude that the short scheduled recordings used for the Stellar device produced equivalent MAP values at better (less) data economy while significantly prolonging implant battery life, thus extending the possible study length as needed for behavioral monitoring in group housed animals to several months.
All‐Extremity Aerobic Exercise Training Improves Carotid Artery Compliance in Older Adults
Authors: Kim Han‐Kyul , Hwang Chueh‐Lung , Yoo Jeung‐Ki , Hwang Moon‐Hyon , Lim Jisok , Handberg Eileen M. , Nichols Wilmer W. , Christou Demetra D.
Published: November 2023

Advancing age is associated with decreased arterial compliance and increased arterial wall intima‐media thickness (IMT), both independent predictors of cardiovascular disease. Aerobic exercise training is a recognized strategy for reducing the risk of cardiovascular disease, however, optimal exercise prescription in older adults remains unknown. The purpose of this study was to examine the effect of all‐extremity aerobic exercise training on central and peripheral vascular structure and function in older adults. Twenty two sedentary older men and postmenopausal women (age 55 to 76 yrs, 64±1yrs; mean±SE), free of major clinical disease (e.g., diabetes, cardiovascular, renal and liver disease) were randomized to 8 weeks of all‐extremity aerobic exercise training (EX; n=12) or non‐exercise control condition (CON; n=10). Aerobic training was performed 4 days/week under supervision and consisted of 47 min of exercise on an air‐braked all‐extremity ergometer (Airdyne, Schwinn) at 70% of maximal heart rate. Central and peripheral vascular structure was assessed by measuring carotid and femoral artery diameter and IMT using high resolution ultrasonography. Vascular function was evaluated by calculating arterial compliance using simultaneous measures of diameter and pressure via applanation tonometry. In response to the exercise intervention, carotid artery compliance improved (EX: 0.12±0.01 vs. 0.14±0.02 mm2/mmHg, P=0.01 and CON: 0.12±0.02 vs. 0.12±0.02 mm2/mmHg, P=0.8; pre‐ vs. post‐intervention). However, carotid artery diameter (EX: 7.1±0.2 vs. 7.1±0.2 mm and CON: 6.8±0.2 vs. 6.8±0.2 mm; P>0.05) and IMT normalized for lumen diameter (EX: 0.09±0.005 vs. 0.08±0.003 and CON: 0.09±0.005 vs. 0.09±0.004; P>0.05) remained unchanged. Femoral artery compliance did not improve with the intervention (EX: 0.17±0.02 vs. 0.16±0.02 mm2/mmHg and CON: 0.17±0.03 vs. 0.14±0.03 mm2/mmHg; P>0.05). Similarly, femoral artery diameter (EX: 8.6±0.4 vs. 8.8±0.4 mm, and CON: 8.5±0.5 vs. 8.6±0.5 mm; P>0.05) and IMT/diameter (EX: 0.07±0.009 vs. 0.07±0.008 and CON: 0.09±0.009 vs. 0.08±0.008; P>0.05) did not change following the intervention. In conclusion, eight weeks of aerobic exercise training performed on an all‐extremity ergometer improves carotid artery compliance in healthy older adults. This finding may have important implications for reducing the risk of cardiovascular disease in older adults.
Internalized silver nanoparticles alter ion transport and hemoglobin spectrum in human red blood cells
Authors: Alla Praveen Kumar , Lauf Peter K , Pavel Ioana , Paluri Arathi , Markopoulos Marjorie , Yaklic Jerome , Adragna Norma C.
Published: November 2023

In the last decades, numerous studies on the industrial and biomedical applications of nanomaterials (NMs) have emerged. For instance, the effect of silver nanoparticles (AgNPs) on red blood cell (RBC) hemoglobin (Hb) was measured by Raman tweezers spectroscopy on single live cells. The findings show that AgNPs of diameter > 100 nm cause irreversible changes in the Hb heme's conformation from the normal oxy‐ to the deoxy‐state, i.e. from the R (relaxed)‐ to the T (tense)‐state. However, less is known regarding the NMs effects at the level of cellular function. Here, we report on the effect of internalized AgNPs on ion transport in human (H) RBCs. Rubidium influx and K concentration were determined in the presence and absence of 100–150 μg/mL negatively charged 10 nm AgNPs. Furthermore, the Hb spectrum under the same experimental conditions as the ion transport studies was also measured. Internalization of AgNPs in RBCs was determined by integration of enhanced dark field optical microscopy and hyperspectral imaging in a CytoViva® equipment. Our preliminary findings indicate that the tested internalized AgNPs inhibit Rb influx and deplete the cells from K by mechanisms currently under investigation. In addition, the AgNPs altered the absorbance for the Hb peaks and showed an additional broad shoulder between 594.1 and 658.8 nm. The changes in the Hb spectrum in the presence of AgNPs could be interpreted as the AgNPs causing an increase in the oxidized form of Hb, i.e. MetHb. Further studies are on the way to establish whether there is a correlation between the changes in Hb oxidative state and the alterations in cellular ionic composition induced by the AgNPs tested.

Support or Funding Information

Supported by National Science Foundation and Wright State University Foundation
Behavioral Comorbidities in Dextran Sulphate Sodium (DSS) Colitis, an animal model of Inflammatory Bowel Diseases
Authors: Nyuyki‐Dufe Kewir , Cluny Nina L , Sharkey Keith A , Swain Mark G , Pittman Quentin J.
Published: November 2023

Inflammatory Bowel Diseases (IBD), which include Crohn's disease and ulcerative colitis represent a group of incurable lifelong diseases affecting about 0.67% of the Canadian population (2012) and severely impacts the health‐related quality of life through ongoing debilitating symptoms like pain, gastrointestinal dysfunction as well as behavioral comorbidities like anxiety, depression, fatigue and cognitive impairment. Depression and anxiety are prevalent in individuals with IBD at a rate that outpaces the general population thereby substantially increasing the burden of the disease, as well as economic cost of managing it. Although clinical surveys and population studies have established a strong relation between IBD, depression and anxiety disorders, our knowledge of CNS changes is limited. We therefore investigated these comorbidities in a mice model of IBD with similarities to Ulcerative colitis, caused by administration of Dextran sulphate sodium (DSS) in drinking water for 5 days. In male and female mice, DSS treatment caused increased increased brain excitability, revealed by a decrease in seizure onset times after intraperitoneal administration of 25mg/kg body weight of Kainic acid; this was positively correlated with the intensity of inflammation only in males. Moreover, both sexes showed an increased anxiety‐related behavior on the elevated plus‐maze (EPM). We assessed pain levels, because they may influence behavioral response; only male mice were hyperalgesic when tested on the hotplate for thermal pain sensitivity indicating that altered behavioral responses cannot be entirely attributed to an interference with a movement brought about by pain. Further studies mapping the CNS pathways integral to the above changes will reveal novel mechanisms as to how peripheral inflammation results in changes in central immune‐mediated affective behaviors.

Support or Funding Information

This work is supported by Alberta Innovates‐Health Solutions (AI‐HS) and Canadian Institutes of Health Research team grants, and by the Hotchkiss Brain Institute and AI‐HS personnel support awards.
A role of hemodynamic stress in carotid stenosis; a study using computational fluid dynamic analyses
Authors: Fukuda Shunichi , Shimogonya Yuji
Published: November 2023

Background

It is difficult to predict cervical carotid stenosis because our current understanding of its risk factors is incomplete. Several reports suggested that carotid arterial geometry is an independent risk factor for carotid atherosclerotic disease in association with disturbed flow. However, there are few reports indicating a quantitative analysis in hemodynamic distributions of carotid stenosis. Thus, we examined here hemodynamic involvement in carotid stenosis using computational fluid dynamic (CFD) techniques.

Methods

Distributions of time‐averaged wall shear stress (TAWSS), time‐averaged WSS gradient (TAWSSG), oscillatory shear index (OSI), gradient oscillatory number (GON) proposed by us, and transverse wall shear stress (transWSS) in stenotic (n=11) and non‐stenotic (n=5) cervical carotid arteries were examined using ANSYS‐CFX software. Patient‐specific arterial geometries and inflow velocities were obtained from 3‐dimentional CTA images and carotid ultrasound Doppler examinations.

Results

TAWSSG in stenotic arteries tended to be higher compared with non‐stenotic arteries (p=0.157). There was a tendency that transWSS and GON, metrics for disturbed flow, were higher in stenotic vessels than non‐stenotic vessels (p=0.112 and 0.234, respectively). Moreover, there were significant increases in TAWSSG and transWSS in severe stenotic arteries (more than 75% in area) compared with non‐stenotic arteries (Figure 1; p=0.0143 and 0.0274, respectively).

Conclusions

The data suggest that CFD analyses in distributions of WSS and disturbed flow may serve to clarify new risk factors for carotid stenosis. We are planning multi‐institutional clinical trial about the issue.

Support or Funding Information

This research was supported by AMED‐CREST, AMED.
Effects of various natural sweeteners on insulin resistance, inflammation and liver steatosis in a rat model of diet‐induced obesity
Authors: Valle Marion , St‐Pierre Philippe , Pilon Geneviève , Anhê Fernando Forato , Varin Thibault , Marette André
Published: November 2023

Background

The detrimental effect of refined sugars on health has been the subject of many investigations. However, very few studies have looked at the long‐term beneficial impact of natural sweeteners in a context of obesity.

Objective

The objective of this study was to compare the metabolic responses following the chronic ingestion of refined simple sugars (sucrose and fructose) to that of various natural sweeteners in a diet‐induced obese insulin‐resistant rat model.

Methods

Rats were fed a high‐fat high sucrose diet (HFHS) for 8 weeks and received daily gavage with a solution of equivalent amount of total carbohydrates from either sucrose, fructose, maple syrup, molasses, brown rice syrup, agave syrup, corn syrup, or honey. A group fed a standard chow diet receiving daily gavage with the sucrose solution was used as a control. Weekly body weight and food intake were assessed. At week 7, glucose tolerance was evaluated by an oral glucose tolerance test (OGTT), while insulin sensitivity was determined using the HOMA‐IR index at 8 weeks. Nonalcoholic fatty liver disease (NAFLD) was assessed by hepatic triglyceride (TG) content and liver inflammation.

Results

Daily gavage with the different natural sweeteners did not lead to differences in food intake or body weight gain. During the OGTT, similar glycemic responses were observed across the different treatment groups. However, the insulin excursions were lower in the maple syrup treated animals suggesting improved insulin sensitivity. Assessment of insulin resistance by calculation of the HOMA‐IR index further revealed that all natural sweeteners except corn syrup significantly improved insulin sensitivity, when compared to sucrose treatments. Furthermore, whereas hepatic TG content was reduced in maple syrup, molasses and agave syrup treated rats, there was an increased TG accumulation in the brown rice and corn syrup treated rats. Hepatic inflammation, as revealed by increased IL‐1B levels in obese rat liver, was also reduced to various extents by gavage of molasses, agave syrup, maple syrup and corn syrup.

Conclusion

Several natural sweeteners used in this study were found to improve insulin sensitivity and to reduce NAFLD as compared to an equivalent amount of sucrose in diet‐induced obese rats. Among the natural sweeteners, maple syrup, molasses and agave syrup appear to exert the most consistent beneficial effects on multiple metabolic health endpoints, suggesting that consumption of those natural sweeteners is a healthier alternative to simple refined sugar.

Support or Funding Information

This project was supported by Agriculture and Agri‐Food Canada from the Agricultural Innovation program, a federal‐provincial‐ territorial initiative in Canada, and with the participation of the Federation of Quebec Maple Syrup Producers.
Oral L‐Tyrosine Supplementation Augments Cutaneous Vasoconstriction to Whole Body Cooling
Authors: Smaller Kevin A , Lang James A
Published: November 2023

Healthy older adults exhibit a blunted cutaneous vasoconstriction (VC) response to cold exposure, which increases their susceptibility to rapid heat loss and hypothermia. We hypothesized that oral supplementation of L‐tyrosine, the primary substrate for catecholamine biosynthesis, would augment the VC response to gradual whole‐body cooling (Tsk = 30.5 °C) in older adults. Eleven young (Y = 24±1 years) and eleven older (O = 68±4‐‐‐‐‐‐ years) participants completed a randomized, double‐blinded, placebo‐controlled, cross‐over study consisting of two visits separated by >3 days. At the beginning of each visit, participants ingested either 150 mg/kg L‐tyrosine or placebo. An hour after consumption, whole‐body cooling commenced, causing a gradual decline in skin temperature from 34 to 30.5 °C over a 30 minute period. Laser Doppler flux (LDF) was measured at the ventral forearm and cutaneous vascular conductance (CVC) was calculated as CVC = LDF/mean arterial pressure and expressed as a percent change from baseline (%ΔCVC). Two minutes of static handgrip exercise (35% MVC) followed by 3 minutes of post‐exercise ischemia was implemented before and toward the end of the cooling bout. No changes in blood pressure or heart rate were identified with tyrosine supplementation. However, the VC response to whole‐body cooling was blunted in older adults (Placebo: Y = 29±3; O = 21±5 %ΔCVC) and this was augmented with tyrosine supplementation (Tyrosine: Y = 37±5; O = 31±4 %ΔCVC; p<0.05). These results indicate that oral L‐tyrosine supplementation restores the VC response to whole‐body cooling in older adults. This suggests that L‐tyrosine may be a limiting factor in the full expression of the cutaneous VC response and supplementation may help maintain body core temperature during cold exposure particularly in an older population.

Support or Funding Information

DMU IOER Grant 03‐14‐01
Thermal Stabilization of Tumor Necrosis Factor‐α and C‐Reactive Protein by Compatible Solutes
Authors: Whitelock Katherine , Lindahl Elizabeth , von Kanel Hannah , Younger Rylan , Jacinto Ariana , Mokhtari Parisa , Wilkinson Steven
Published: November 2023

Prokaryotic and Eukaryotic organisms are known to respond to various forms of stress by increasing intracellular concentrations of small organic compounds, called compatible solutes. These compounds increase survival in response to extremes of osmolarity, pH, temperature, desiccation and chemical denaturants. The protective properties of these compounds are largely the result of the stabilization of cellular macromolecules, and significant progress has been made in elucidating the mechanisms by which this stability is conferred. Compatible solutes belong to multiple chemical classes, with differing protective properties that appear to be stress‐specific and likely with various degrees of target specificity. Here we describe initial screening efforts to quantify the thermal stabilization properties of two prominent classes of compatible solutes, small carbohydrates and amino acids. Two model proteins of diagnostic significance were chosen for these studies: tumor necrosis factor (TNF) and C‐reactive protein (CRP). These data indicate that specific members of these molecular classes within certain concentration ranges confer significant thermal stabilization to each of these proteins. These findings present interesting possibilities for future improvements in the field of medical diagnostics, specifically in the area of patient sample collection and transport where the stabilization of low concentration, labile proteins is a major concern.
Acute Exhaustive Exercise Protects Against Olanzapine‐Induced Hyperglycemia In Male C57BL/6J Mice
Authors: Castellani Laura N , Peppler Willem T , Sutton Charles D , Wright David C
Published: November 2023

Second generation antipsychotics (SGAs) such as olanzapine are efficacious in treating symptoms of schizophrenia and bipolar disorders. However, use of SGAs is linked to robust metabolic disturbances. Notably, acute olanzapine (OLZ) exposure has been shown to result in rapid impairments in glucose homeostasis. Given the reputed ability of exercise to promote insulin‐independent glucose uptake as well as to improve insulin sensitivity and potentiate glucose stimulated insulin secretion, the purpose of the present study was to assess the ability of exercise to protect against acute OLZ‐induced hyperglycemia. Male C57BL/6J mice were exercised to exhaustion (20% incline, approximately 75 minutes) or remained sedentary immediately prior to olanzapine treatment (5mg/kg; intraperitoneal injection). Interestingly, previously exercised mice were protected against OLZ‐induced increases in blood glucose and this was accompanied by an increases in serum interleukin‐6 (IL‐6), total glucagon‐like peptide‐1 (GLP‐1) and insulin. The protective effect of exhaustive exercise against increases in blood glucose by OLZ was maintained 3‐hours post‐exercise. In contrast, moderate exercise (15m/min, 5% incline, 75 minutes) did not protect against OLZ‐induced increases in blood glucose, nor were there measurable increases in serum insulin, IL‐6 or GLP‐1. In conclusion, the current study suggests a protective effect of exhaustive exercise against acute OLZ‐induced elevations in blood glucose, perhaps as a result of exercise‐induced increases in an IL‐6‐GLP‐1‐insulin signaling axis.
Bicarbonate secretion in human small airways
Authors: Shamsuddin A K M , Quinton Paul M
Published: November 2023

Cystic Fibrosis (CF) pathology is attributed to a basic defect in epithelial anion transport. The loss of bicarbonate (HCO3−) transport in CF plays a critical role in pathogenesis by interrupting the normal formation and release of mucins in exocrine tissues as in pancreas, liver and intestines in CF, we do not know whether HCO3− secretion occurs in normal human native small airways, the most prevalent site of morbidity and mortality in CF. Using our recently developed mini‐Ussing chamber system to determine the properties of HCO3− transport in freshly dissected human airways (diameter ≈ 2.0 mm). We assayed HCO3− transport by measuring the transepithelial potential, conductance and equivalent short circuit current with bilateral 25 mM NaHCO3− plus 125 mM NaGlu in presence of luminal amiloride. Under these conditions since the only major transportable anion present was HCO3−, we took the short‐circuit current to be a direct measure of HCO3− transport in small airways. Applying selective agonists and/or inhibitors, we show that human native small airways constitutively secrete HCO3−, and could be further stimulated agonists mediated by cAMP (adrenergic) and Ca2+ (purinergic) and respectively inhibited by selective antagonists. These results suggest at least two pathways for HCO3− secretion, one dependent on Cystic fibrosis transmembrane conductance regulator (CFTR) and another dependent on a calcium‐activated chloride channel (CaCC), that secrete HCO3− into the airway luminal surface liquids, to critically support the discharge of mucins and maintain airway surface liquid pH for optimal defense and hygiene of small airways. By analogy with other organs in CF, failure to secrete HCO3− likely results poor mucociliary and pathogen clearance and thus should be seen a new target for therapy in CF and possibly other airway diseases.

Support or Funding Information

Supported by the Nancy Olmsted Trust, the Cystic Fibrosis Foundation and Cystic Fibrosis Research, Inc.
Enhanced Hepatic Insulin Sensitivity With Inhibited Gluconegenesis In Native High Altitude Rats
Authors: AL‐Hashem Fahaid Hassan , Al‐Musa Hassan
Published: November 2023

Background

high‐altitude (HA) populations had lower basal glucose levels as compared to low altitude (LA) natives and the mechanism(s) behind this is lacking. Interestingly, insulin, 5′ adenosine monophosphate‐activated protein kinase (AMPK) are able to restrain hepatic gluconeogenesis by inhibiting expression of Glucose 6‐phosphatase (G6Pase) and Phosphoenolpyruvate carboxykinase (PEPCK).

Aim

To test the hypothesis that HA have lower rate of hepatic gluconeogenesis due to enhanced insulin signaling and/or activation of hepatic AMPK under both basal and glucose stimulation.

Methods

Male rats of match aged, diet, genetic background and native to LA and HA areas were used. Fating plasma glucose and insulin levels were determined after which i.p glucose, pyruvate and insulin tolerance tests (IPGTT, IPPTT and IPITT, respectively) were carried out. Under basal or after insulin stimulation, liver samples were collected and real‐time reverse transcription‐PCR (qRT‐PCR) and western blotting were carried out.

Results

HA rats had stable basal insulin levels with significant lower basal glucose levels and Insulin resistance index (HOMA‐IR) with enhanced glucose clearance and insulin tolerance. Gluconeogenesis was significantly inhibited in HA rat as evident by decreased glucose production after IPPTT. HA rats had inhibited lower protein levels of Glucose transporter 2 (GLUT‐2) and G6Pase and PEPCK under basal and insulin stimulation. Concomitantly, HA rats had had higher levels of the following antibodies p‐IRS(tyr 612), p‐Akt and p‐FOX01 and lower levels of p‐mTOR/p‐70S6K/P‐IRS(ser307) suggesting enhanced hepatic insulin signaling. however, levels of AMPK, p‐AMPK and AS160 were not significantly different between LA and HA rats.

In conclusion, our novel data is the first to show that HA native rats exhibit lower glucose levels and HOMA‐IR, at least, due to inhibited gluconeogenesis which is mediated through enhanced hepatic insulin but not AMPK signaling.
Hyperbaric oxygen therapy attenuates muscle atrophy in streptozotocin‐induced diabetic rat
Authors: Yoshikawa Madoka , Tanaka Masayuki , Zeidan Hala , Nakanishi Ryosuke , Hirayama Yusuke , Ueno Mizuki , Maeshige Noriaki , Fujino Hidemi
Published: November 2023

Diabetes mellitus leads to muscle atrophy, and inflammation especially in the fast fibers of skeletal muscles. Hyperbaric oxygen (HBO) has anti‐inflammatory properties and reduces the inflammation in tissues. Therefore, we examined the effect of HBO on muscle atrophy in the plantaris muscles of diabetic rats. Male Wistar rats were randomly divided into three groups: control group, diabetes group and diabetes plus HBO group. Diabetes was induced by injection of streptozotocin (i.v., 100–140 mg/kg). Diabetes plus HBO group were exposed to 1.25 atmospheric pressure with 36 % oxygen concentration for three hours a day for 8 weeks. Blood glucose level was significantly higher in both diabetes groups than control group. The muscle mass and cross‐sectional area (CSA) of the fast fibers in the skeletal muscle were also significantly lower in both diabetes groups than control group. Meanwhile, the muscle mass and CSA of the fast fibers in the skeletal muscle of diabetes plus HBO group were significantly higher compared to those in diabetes group. These results indicate that hyperbaric oxygen therapy would exert anti‐inflammatory properties and attenuate muscle atrophy in diabetes.
Is The Cardiac Baroreflex Gain Altered in Spontaneously Hypertensive Rats?
Authors: Bonagamba Leni G.H. , Amorim Mateus R. , Moraes Davi J.A. , Machado Benedito H.
Published: November 2023

There is evidence that a reduction in the baroreflex gain contributes to the high blood pressure in SHR. In the present study performed in conscious freely moving rats, we hypothesized that the baroreflex gain was not altered in SHR. To address this question we used two methods for evaluation of the cardiac baroreflex: a) the sequence analysis technique, and 2) the peak of changes in heart rate in response to increase (phenylephrine, PHE) and decrease (sodium nitroprusside, SNP) in mean arterial pressure (MAP) of Wistar (n=15) and SHR (n=21). The sequence analyses were used to evaluate the cardiac baroreflex function over the natural range of variation of arterial pressure, without any pharmacological tools. Considering that the sequence analyses are restricted to a narrow range of arterial pressure variability, we also evaluated the maximal bradycardic response (peak) to pressor response to PHE (i.v.) as well the maximal tachycardic response (peak) to fall in pressure in response to SNP (i.v). All experimental protocols were performed in conscious freely moving rats, previously anesthetized for catheterization of the femoral artery (arterial pressure recordings) and vein (i.v. injections), which were approved by the institutional ethical committee (#187/2011). The peak of reflex bradycardia in SHR in response to PHE was evaluated during the normalization of the MAP by continuous infusion of SNP (from 140 ± 2 to 101 ± 1 mmHg). The data from the sequence analyses show that the slopes of these sequences in both groups were similar (1.89 ± 0.2 vs 2.03 ± 0.2 ms mmHg−1), while the data from changes in MAP in response to PHE (49 ± 4 vs 39 ± 2 mmHg) show that the peak of bradycardic response in SHR was similar to Wistar (−107 ± 13 vs −91 ± 5 bpm). With respect to the reflex tachycardia to fall in MAP in response to SNP (−39 ± 3 vs −51 ± 12 mmHg) it was observed that the peak of tachycardia in SHR was also similar to Wistar (+107 ± 7 vs +112 ± 15 bpm). The data of this study, using two different experimental approaches, are showing that the gain of the cardiac baroreflex in SHR is not altered when compared to Wistar rats. We conclude that changes in the autonomic cardiac components of the baroreflex are not contributing to the high level of MAP observed in SHR.

Support or Funding Information

FAPESP and CNPq
Obstructive Apnea Induces Similar Sympathetic Activation Across Several End Organs Independently of Chemoreceptors Afferents
Authors: Ferreira Caroline B , Schoorlemmer Gus H. , Cravo Sergio L , Stocker Sean D
Published: November 2023

Obstructive sleep apnea increases muscle sympathetic nerve activity (SNA) in humans that contributes to cardiovascular dysfunction including hypertension. Several studies suggested that hypoxia is the main mechanism involved in the sympathoexcitation. The purpose of the present study was to determine whether there are regional difference in apnea‐induced sympathetic activation and asses the contribution of carotid chemoreceptors in cardiorespiratory and sympathetic responses induced by apnea. Male Sprague‐Dawley rats (270–350 g) were anesthetized with urethane (1.2 g/kg IV) and prepared for simultaneous recording of renal, splanchnic, and lumbar SNA, phrenic nerve activity (PNA) and arterial blood pressure (ABP). Apneas were performed by clamping a tracheal tube over 20 s while rats were spontaneously breathing room air and repeated in 100%O2. Apneas in room air produced similar increases in SNA across several nerves (Δ lumbar: 117±14%; Δ renal: 114±17% and Δ splanchnic: 124±12), hypertension (Δ: 12±2 mmHg), and increased PNA amplitude (Δ: 755±121%) whereas decreased of PNA frequency (Δ: −70±5 burst/m). Hyperoxia reduced the sympathetic activation (Δ lumbar: 56±6%; Δ renal: 40±4%, Δ splanchnic: 47±9%), pressor response (Δ: 6±1) and PNA amplitude (Δ: 570 ± 94%) induced by apnea. In a separate group of rats, to test the contribution of the peripheral chemoreceptor afferents, carotid bodies were bilaterally inactivated. Cardiorespiratory and sympathetic responses by NaCN (0.04%) were abolished but not apnea‐induced responses. Pre‐treatment with ganglionic blockade (chlorisondamine, 5 mg/kg IV) abolished apnea‐induced hypertension (Δ: 2±1mmHg). A last series of experiments were design to assess the effect of neuronal activity blockade and the role of glutamate receptor into NTS. Muscimol or AP5+CNQX cocktail reduced pressor and respiratory responses with no change in sympathetic activation evoked by apnea. Otherwise, importantly reduced cardiorespiratory and sympathetic responses induced by NaCN. Collectively, these findings suggest that other mechanisms rather than hypoxia might contribute for increase in sympathetic outflow induced by obstructive apnea.

Support or Funding Information

Coordination for the Improvement of Higher Education Personnel (CAPES) and NHLBI R01 HL‐113270, American Heart Association Established Investigator Grant
Utilizing ATP‐Dependent Chromatin‐Remodeling Complexes to Study Vascular Biology
Authors: Crosswhite Patrick
Published: November 2023

In eukaryotic cells, ATP‐dependent chromatin‐remodeling complexes aid in the regulation of gene replication, transcription, and DNA repair because nuclear factors necessary for achieving these tasks cannot access DNA when it is tightly bound to histones. Recent investigations have revealed that the switching/sucrose nonfermenting (SWI/SNF) and chromodomain helicase DNA‐binding (CHD) group of complexes are critical for embryonic vascular development. Our understanding of chromatin‐remodeling complexes in postnatal blood vessels however, remains inadequate. This study aims to characterize the expression of the SWI/SNF and CHD complexes in two models that alter vascular homeostasis: a hypertensive and aging model. In the aging model, transcripts of the SWI/SNF complex containing Brahma were aberrantly expressed in kidney samples, an organ vital to maintaining proper fluid balance and blood volume. Due to their ability to impact gene transcription in vascular cells (endothelial and smooth muscle), chromatin‐remodeling complexes are ideal molecular tools to aid in the identification of novel genes and signaling pathways involved in pathological changes in blood vessels. These initial findings emphasize the need to further investigate mechanistically how chromatin‐remodeling complexes can regulate vascular homeostasis.

Support or Funding Information

AHA POST#21180005
A Micropuncture Study of the Net K Secretion in Thick Ascending Limb of Mice on a Low Na High K Diet
Authors: Wang Bangchen , Wen Donghai , Yuan Yang , Cornelius Ryan J , Li Huaqing , Wang‐France Jun , Sansom Steven C
Published: November 2023

Understanding the effect of a cardio‐ and reno‐protective low Na high K diet (LNaHK) on renal K handling is crucial to choosing diuretics and anti‐hypertensives for patients on such diets. We previously showed that furosemide, an inhibitor of the Na‐K‐Cl cotransporter (NKCC2) in the thick ascending limb (TAL), increased urinary K excretion (UKV) in mice on a control diet but decreased UKV in mice on LNaHK. We hypothesized that there is a net K secretion in the TAL of mice on LNaHK. Male C57BL/6 mice were given either a control diet or LNaHK for 7–14 days. Mice were anesthetized and received modified saline (140mM NaCl, 5mM KHCO3, 2% mannitol) intravenously. Free‐flow micropuncture was performed using K‐selective micro‐electrodes to measure the K concentration in the early distal tubule (EDT) before and after intravenous administration of vehicle (60μL 0.9% NaCl) or furosemide (60μL, 2mg/mL). Urine was collected via a bladder catheter. Urine Na concentration was measured by a flame photometer. Within 10 minutes of administration, furosemide increased [K] in the EDT of mice on a control diet (Δ = 1.88 ± 0.45 mM; N = 3) but decreased that of mice on LNaHK (Δ = −3.52 ± 0.85 mM; N = 4). Vehicle did not affect [K] in the EDT of mice on either diet. The increase in urinary Na excretion after furosemide was much greater in mice on LNaHK (1298 ± 354; N = 5 vs. 240 ± 56 nmol/min; N = 3). These results indicate that there is a net K secretion in TAL of mice on LNaHK, and it is associated with increased NKCC2 activity.

Support or Funding Information

This project was supported by NIDDK: F30 DK108456, RO1 DK092474.
Molecular Diversity of Pulmonary Sensory Neurons Revealed by Single Cell RNA Sequencing
Authors: Liu Yin , Krasnow Mark A
Published: November 2023

Pulmonary sensory neurons are primary sensory neurons that monitor lung physiological state, and communicate that information to the central nervous system. Many symptoms associated with pulmonary diseases, such as chronic cough, dyspnea (breathlessness), and airway hyperresponsiveness, are presumed to result from abnormal behaviors of these neurons. Past studies indicate that pulmonary sensory neurons are heterogeneous in their morphologies, functions and molecular identities. However, a complete understanding of their molecular and functional diversity is still lacking. Here, we perform single cell RNA sequencing (scRNA‐seq) on mouse pulmonary sensory neurons to elucidate the genome‐wide expression profile of over a hundred individual pulmonary sensory neurons. Through unbiased clustering analysis of the expression data of these neurons, we define 7 major classes of pulmonary sensory neurons. Each class expresses distinct sets of genes implicated in physiological sensing, which predict the specific sensory functions of each class. The gene expression profiles also identify specific molecular markers for each class, which we are using to elucidate their structures, map their terminal locations and receptive fields in the lung, measure their activity, identify their synaptic partners, and reveal the physiological consequences of their activation.

Support or Funding Information

Damon Runyon Postdoctoral Research Fellowship (Y.L.)

M.A.K. is an investigator of the Howard Hughes Medical Institute
Investigation of the effects of titanium dioxide and cerium oxide nanoparticles on liposomes using fluorescent dye leakage
Authors: Foster Brandon , Larios Mitchell , Smith Virginia
Published: November 2023

Nanoparticles are common additives in many consumer products and medicines, including foods, toothpaste, and other personal care items. Despite their ubiquity, there has been limited research into the disruptive effect of nanoparticles on biological membranes. Using synthetic liposomes as model membranes, we used fluorescent dye leakage to analyze the effects of two types of nanoparticles: titanium dioxide nanoparticles, which are used to whiten and brighten products, and cerium nanoparticles, which have shown promise as biological anti‐oxidants. Liposomes were formed from different types of purified lipids using the extrusion method. The pH‐dependent dye fluorescein was trapped inside the liposomes, which was maintained at pH 10 by a glycine buffer, while the buffer outside the liposomes was maintained at a neutral pH where the dye would be quenched. By monitoring the fluorescence emission intensity of the liposome solution as nanoparticles were added, it was possible to determine rates of leakage as a function of NP concentration, solution temperature, and NP diameter. Controls were performed in the absence of nanoparticles and in the presence of known membrane disruptors such as detergents. In conclusion, we have developed an assay to investigate the disruption of lipid bilayers by nanoparticles. Preliminary results from the assay indicate that low micromolar concentrations of nanoparticles increase the rate of dye leakage from the liposomes by more than a factor of two, consistent with particle interaction and membrane disruption. These results will be presented in the context of a larger, ongoing study that investigates mutagenicity and cytoxicity of nanoparticles.

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Defense Threat Research Agency
Making Science PhUn: Build, Design, and Connect
Authors: Silveyra Patricia , Chiota Lauren , Nagarajan Padmanabhan
Published: November 2023

To celebrate PhUn week, Milton Hershey School high school students in Anatomy and Physiology classes hosted Dr. Patricia Silveyra, a lung physiologist, APS member, and Assistant Professor at the Penn State College of Medicine. The visit objectives included discussion about lung physiology, diseases of the lung, and what diagnostic tools doctors use to assess lung function and diseases such as COPD and asthma.

The visit also included a hands‐on activity that required students to build, design, and test a homemade spirometer; a diagnostic tool doctors use to measure lung function. Students used various materials such as plastic 2‐liter and 4‐liter bottles and plastic tubing to design and build their spirometer. Once the spirometer was prepared students were able to test their design. Students measured and recorded their vital capacity (VC), total lung capacity (TLC), residual volume (RV), and expiratory reserve volume (ERV). Future lessons on lung function and physiology required students to revisit their measurements to graph and analyze their values. Identifying differences between values observed for normal lung function and those measurements observed in patients with lung diseases will be a cumulative activity.

Students appreciated the opportunity to learn from a professional in the medical field. Dr. Silveyra was able to connect with the students very easily and relate the activity to the student's lives. The students benefited from the application and authenticity of the build, design, and test spirometer model activity.
Monitoring the Effect of Diet and Dietary Supplements on Lipid Accumulation in Drosophila melanogaster Larvae: An Opportunity to Provide a Course‐Based Undergraduate Research Experience
Authors: Daggett Melissa A. F. , Torres Alejandra Nunez , McFarlin Shane , Goodroad Samual L.
Published: November 2023

Drosophila is an emerging model organism in which to study the effects of diet on the regulation of metabolism and physiological function. In order to analyze the effect different diets and food additives have on the accumulation of lipids in Drosophila larvae, we have used a carbohydrate rich and optimized high protein diet to expand on an established method to monitor the accumulation of lipids in third in star Drosophila larvae known as the floating larvae assay. We report on the simplicity and utility of using the floating larvae assay to access changes in lipid accumulation in flies raised on different diets and dietary supplements. Procedures for expanding the assay using common molecular, biochemical and cellular techniques in an upper level teaching laboratory, and in offering and delivering a course‐based undergraduate research experience is presented.

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Missouri Western State University PORTAL (Program of Research Teaching and Applied Learning)
Unfolded protein response regulates yeast Arl1p activation at late‐Golgi via phosphorylation of Arf GEF Syt1p
Authors: Lee Fang‐Jen Scott , Hsu Jia‐Wei , Tang Pei‐Hua , Wang I‐Hao , Liu Chia‐Lun , Chen Wen‐Hui , Tsai Pei‐Chin , Chen Kuan‐Yu , Chen Kuan‐Jung , Yu Chia‐Jung
Published: November 2023

ADP‐ribosylation factor (Arf) GTPases are key regulators of membrane traffic at the Golgi complex. In yeast, Arf guanine nucleotide‐exchange factor (GEF) Syt1p activates Arl1p, which was accompanied by accumulation of golgin Imh1p at late‐Golgi, but whether and how this function of Syt1p is regulated remains unclear. Here, we report that the Ire1p‐mediated unfolded protein response (UPR) modulated Arl1p activation at the late‐Golgi. Arl1p activation was dependent on both kinase and endo‐RNase activities of Ire1p. Moreover, constitutively active Hac1p restored the Golgi localization of Arl1p and Imh1p in IRE1‐deleted cells. Elucidating the mechanism of Ire1p‐Hac1p axis actions, we found that it regulated phosphorylation of Syt1p, which enhances Arl1p activation, recruitment of Imh1p to the Golgi, and Syt1p interaction with Arl1p. Consistent with these findings, the induction of UPR by tunicamycin treatment increases phosphorylation of Syt1p, resulting in Arl1p activation. Thus, these findings clarify how the UPR influences the roles of Syt1p, Arl1p, and Imh1p in Golgi transport.

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National Science Council of Taiwan (NSC‐104‐2320‐B‐002‐048‐MY3)
Chlorinated Lipids Induce Increased Cortical Stiffness in Microvascular Endothelial Cells
Authors: Birkhead Travis Michael , Kalogeris Theodore , Yu Hong , Meininger Gerald , Ford David , Ronald Korthuis
Published: November 2023

Elastic properties of the vascular endothelium are critical to its role in controlling blood flow, pressure, vascular tone, adhesion of platelets and leukocytes, permeability and other homeostatic functions. Dysregulation of these endothelial functions are hallmarks of the inflammation produced in response to ischemia‐reperfusion, but it is not clear to what extent altered endothelial elasticity plays a role in the endothelial response to specific pro‐inflammatory stimuli. Cellular and plasma lipids that have been chlorinated by reacting with hypochlorous acid (HOCl) produced by neutrophil myeloperoxidase (MPO) have been shown to increase several markers of endothelial inflammatory activation. However, their effect on endothelial elasticity is unknown. We have begun to explore this issue in cultured endothelial cells. Human microvascular endothelial cells (HMEC‐1) were cultured to varying levels of confluence, incubated with 10 μM of 2‐chlorohexadecanoic acid (Cl‐HA), hexadecanoic acid (HA), 2‐chlorohexadecanal (Cl‐HDA), or hexadecanal (HDA), or 10 ng/ml TNF‐α, and cortical stiffness was measured using atomic force microscopy (AFM). Treatment with chlorinated lipids showed confluence‐dependent increases in stiffness, while non‐chlorinated lipids tended to decrease stiffness when compared with EtOH diluent. While the effect of chlorinated lipid varied with confluence, TNF‐α (positive control) produced consistent results independent of culture confluence. These results show for the first time, that the chlorinated lipids known to be produced through reaction with neutrophil MPO‐derived HOCl, increase cortical stiffness in microvascular endothelial cells.

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RO1‐GM115553 & R01‐AA221081
TRPA1 Makes You Feel The PA1N
Authors: Sampe David
Published: November 2023

About 3–4% of people worldwide suffer from chronic pain. The United States spends $60 billion annually treating pain. Current treatments are ineffective; opioids are addictive and lose efficacy while pregabalin, a non‐opioid neuropathic pain drug, only works in 30% of patients. Pain receptors (nociceptors) are activated chemically or mechanically. The nociceptor transient receptor potential cation channel, subfamily A, member 1 (TRPA1) is an ion channel located in the membranes of free nerve endings in the skin. TRPA1 is activated by mechanical stretching, and has many active sites where ligands (e.g. tear gas, mustard gas, and wasabi) can bind to open the channel. Once opened, Ca2+ ions (or Na+ ions) pass through, depolarizing the neuron. Structurally, TRPA1 is a tetramer, with each subunit containing several domains. In the pre‐S1 domain, ligands bind covalently to the sulfurs at Cys621, Cys641, Cys665, and Lys710. The TRP‐like domain opens for ion passage. The ankyrin repeat domain contains 16 recurring sequences of 33 residues, and may be involved with the stretch activation of TRPA1. In domains S1–S6, a‐helices hold the protein's shape and contain binding sites for agonists to open the channel and for antagonists (which block function). One antagonist, A‐967079, binds in a pocket around Phe909, forming a wedge to prevent movement and function of TRPA1. Researchers aim to develop a TRPA1 antagonist that will help treat pain sufferers. The Brown Deer SMART (Students Modeling A Research Topic) Team constructed a model of TRPA1 using 3D printing technology to assist researchers in studying its structure and function.