bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of mitochondrial function in human atrial tissue by remote ischemic conditioning
Authors: Kleinbongard Petra , Gedik Nilguen , Frey Ulrich , Zandi Afsaneh , Thielmann Matthias , Jakob Heinz , Peters Jürgen , Kamler Markus , Heusch Gerd
Published: June 2021

Introduction

Remote ischemic preconditioning (RIPC), repeated cycles of brief limb ischemia/reperfusion, attenuates postoperative troponin release in patients undergoing surgical coronary revascularization and improves clinical outcome in some, but not all studies. Mitochondria are the end‐effectors of cardioprotection by local ischemic conditioning maneuvers in experimental studies. Here, we now analyzed mitochondrial function in response to RIPC in human atrial tissue.

Methods

Patients undergoing elective surgical coronary revascularization under isoflurane anesthesia were randomized to RIPC by 3× 5 min/5 min upper arm blood pressure cuff inflation/deflation or placebo (n=30/30), and their right atrial appendages were harvested prior to ischemic cardioplegic arrest. Cardioprotection was reflected by a 14% decrease with RIPC vs. placebo in the area under the curve of serum troponin I/T concentrations over 72 h after surgery. Mitochondria were isolated from the atrial tissue (n=10/10). Mitochondrial function, i.e. mitochondrial respiration, adenosine triphosphate (ATP) production, reactive oxygen species (ROS) production and calcium retention capacity (CRC) to estimate mitochondrial permeability transition pore (mPTP) opening, was measured at physiological temperature of 37°C. Data are given as mean±SEM.

Results

Associated with the observed cardioprotection in patients, mitochondrial function was improved by RIPC. Basal respiration was not different between RIPC and placebo. ADP‐stimulated complex I respiration was significantly greater with RIPC than with placebo. Mitochondrial complex IV respiration and maximal oxygen uptake of uncoupled mitochondria were not different between RIPC and placebo, reflecting an equal loading of viable mitochondria (Figure 1A). The mitochondrial ATP production (Figure 1B) was greater whereas mitochondrial ROS production (Figure 1C) was less with RIPC than with placebo. CRC of mitochondria (Figure 1D) was improved with RIPC in comparison to placebo, with and without cyclosporine A.

Conclusion

In human myocardium, mitochondria are an intracellular target of protection by RIPC.

Support or Funding Information

Supported by: German Research Foundation (SFB 1116 B8)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Acute Chronotropic Effect of the Uremic Metabolite, Trimethylamine‐N‐Oxide (TMAO), on Mouse Cardiac Muscle
Authors: Sanborn David Michael , Oakley Carlee , Grillo Michael , Vallejo Julian , Rafie Nikita , Wacker Michael
Published: June 2021

Background

While it is understood that patients with chronic kidney disease (CKD) have an increased propensity for developing cardiovascular disease, the exact mechanisms remain unclear. Growing evidence suggests that the gut microbiome and its byproducts, such as TMAO, may be important contributors to this pathologic process. This uremic metabolite is cleared through renal excretion, which is compromised in CKD patients. Therefore, CKD patients often possess elevated plasma levels of this substance. In a previous study, we found that TMAO at pathological concentrations directly increases cardiac contractility in isolated, paced hearts. In this study, we sought to determine if TMAO also has chronotropic effects on isolated, spontaneously beating mouse hearts.

Methods

Whole mouse hearts were extracted from anesthetized CD1 adult mice and subsequently connected to a force transducer and bubbled with oxygen inside an organ bath. The atria and sinoatrial node were kept intact to allow for spontaneous beating without artificial pacing. Changes in heart rate (in beats per minute) were measured after treatment with TMAO (3,000 μM) or vehicle (Ringer's solution). Additionally, calcium imaging was performed on cultured spontaneously beating embryonic rat cardiomyocytes. Intracellular Ca2+ responses in rat primary cardiomyocytes were measured with the fluorescent Ca2+ indicator Fura‐2 AM in response to vehicle and TMAO (3,000 uM).

Results

Average beating frequency (in beats per minutes) of isolated hearts increased by 27% following treatment with 3,000 μM TMAO (P < 0.05, n =3) while there was no change with vehicle. Regarding isolated myocytes, TMAO was found to have a direct chronotropic effect as it increased beating frequency (as measured by calcium waves) by 13% compared to vehicle treatment (P < 0.05, n =4–5).

Conclusions

In addition to our previously described inotropic effects in the mouse heart, pathologic concentrations of TMAO also have a direct and positive chronotropic effect. The direct effects we have observed on the heart may increase cardiac output in early stages of CKD. However, cardiac remodeling as a result of increased beating frequency and contractility may have pathologic consequences in those with chronic disease. Further research is needed in order to elucidate the effect that TMAO has on cardiovascular function and pathology during CKD.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Moderate exercise training under constant light condition amplifies inflammatory signals through disruption of splenic clock mechanism in osteoarthritic animals
Authors: Hong Yunkyung , Hossain Mohammad Farhad , Hong Yonggeun
Published: June 2021

Physical exercise has been recommended for osteoarthritic(OA) patients, the effects of which depends on exercise protocol. Here, we determined whether the benefits of exercise are influenced by lighting condition in the OA rats. Moderate treadmill exercise(Ex) was performed for 4 weeks at ZT14 under 12:12hr light‐dark(L/D) as well as constant light(LL). Intervention was applied for 30 min on 5 days/week. Splenic Cry1 expression was suppressed in the trained rats under constant light condition, leading to upregulation of proinflammatory cytokines mRNA. Moreover, TNFα level in serum was higher in the LL+Ex group than the L/D+Ex group. Constant light combined with exercise exacerbated primary cartilage lesion through an increase of catabolic molecules as well as a transcriptional suppression of anabolic factors. The level of synovial RANKL protein was elevated in the LL+Ex group, leading to loss of tibial trabeculae. And increased joint diameter was not recovered in the exercise‐trained rats under LL condition. Exercise training under constant lighting condition enhanced activation of catabolic machinery in soleus as well as gastrocnemius muscle. Treatment of proinflammatory cytokines disrupted rhythmic expression of catabolic enzymes in C2C12‐derived myotubes. Taken together, lighting condition might be a considerable environmental factor to obtain exercise‐induced benefits.

Support or Funding Information

Funding: NRF‐2015R1C1A2A01055691, NRF‐2017R1A2A2A01067169, KGM4611714

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Left Ventricular Strain and Strain Rate Responses to Submaximal Exercise in Prostate Cancer Patients Treated with Androgen Deprivation Therapy
Authors: Post Hunter K. , Lovoy Garrett M. , Banister Heather R. , Sutterfield Shelbi L. , Caldwell Jacob T. , Ade Carl J.
Published: June 2021

Introduction

Androgen Deprivation Therapy (ADT), like that used to treat prostate cancer patients, increases cardiovascular disease risk and mortality. Administration of ADT impairs left ventricular mechanics in animal models, however, it remains poorly understood how ADT influences cardiac function in human prostate cancer patients. Therefore, the aim of the current investigation was to non‐invasively measure left ventricular mechanics at rest and during submaximal exercise in prostate cancer patients with and without a history of ADT treatment. We hypothesized that change in left ventricular strain, strain rate, and tissue velocities during the rest‐to‐exercise transition would be impaired in those with a history of ADT treatment compared to those with no prior ADT.

Methods

To date, 7 prostate cancer patients (66 ± 7 yrs) have completed the experimental protocol. Cancer subjects (n=3 treated with ADT; n=4 no history of ADT) performed echocardiographic measurements at rest and during a supine submaximal cycling exercise to a target heart rate of 100 beats/min. Tissue Doppler echocardiography was used to measure myocardial tissue velocities in systole (S′) and early diastole (E′). In addition, myocardial deformation was assessed via measurements of left ventricular strain (S), and strain rate (SR) from the mid‐interventricular septum. Systolic and diastolic reserve indices were calculated from myocardial velocities.

Results

The change in systolic S from rest to exercise was significantly different between groups (ADT: 2.8 ± 1.5 %; Non‐ADT: −3.3 ± 4.2 %; p=0.03). The change in systolic SR from rest to exercise was significantly different between groups (ADT: −0.037 ± 0.6 1/s; Non‐ADT: −0.23 ± 0.15 1/s; p=0.03). There were no changes observed between groups from rest to exercise in early diastolic filling SR (ADT: 0.74 ± 0.47 1/s; Non‐ADT: 0.86 ± 0.35 1/s; p=0.35), systolic reserve index (ADT: 2.27 ± 0.07; Non‐ADT: 0.86 ± 1.4; p=0.07), and diastolic reserve index (ADT: −5.05 ± 2.1; Non‐ADT: −2.9 ± 2.5; p=0.14). There were also no significant changes observed between groups in S′ (ADT: 0.034 ± 0.033 cm s−1; Non‐ADT: 0.0017 ± 0.02 cm s−1; p=0.09), and E′ (ADT: 0.046 ± 0.025 cm s−1; Non‐ADT: 0.033 ± 0.033 cm s−1; p=0.31).

Conclusion

This preliminary evidence suggests that ADT in prostate cancer patients significantly impairs left ventricular function as determined by changes in systolic SR and S in response to submaximal exercise. These findings may hold significant value beyond the basic characterization of left ventricular function, in particular as part of a risk‐stratification strategy in prostate cancer patients receiving ADT.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Heart Rate Alters but Does Not Improve Calorie Predictions in Fitbit Activity Monitors
Authors: Vusich John W. , Mitrzyk John , Wiersma Matthew , Montoye Alexander HK.
Published: June 2021

Consumer‐based activity monitors such as Fitbit use accelerometers and possibly heart rate (HR) in proprietary prediction models to estimate calories (kcals). In theory, including HR in a kcal prediction model should improve kcal prediction since HR is a physiologic measure of effort; however, this has not yet been tested for consumer‐based activity monitors.

PURPOSE

To determine if Fitbits measuring HR estimate kcals differently than Fitbits without HR.

METHODS

Participants (n=23) performed nine activities in the laboratory for five minutes each, split into four groupings (G1: sitting, standing, cycling 50–150W, G2: level and inclined (10%) walking at 2.5 miles/hour, G3: level and inclined (10%) walking at 2.5–3.2 miles/hour, G4: level and inclined (3%) jogging at 5–10 miles/hour). These groupings were specifically designed to elicit similar steps for activities but different HR and kcal expenditure. Participants wore five Fitbits, three on the dominant wrist (proximal to distal: Blaze, Alta HR, Alta) and two on the non‐dominant wrist (Charge HR proximal to Flex 2). Three Fitbits (Blaze, Charge HR, Alta) assessed steps, HR, and kcals, and two Fitbits (Alta, Flex2) assessed steps and kcals during each activity. Estimates from the Fitbits were compared to criterion measures, between Fitbits measuring HR and Fitbits without HR, and for each activity grouping, using repeated measures analysis of variance.

RESULTS

Fitbits with HR had significantly higher kcal predictions (10.5–23.8% higher, p<0.05) during inclined walking/jogging than level walking/jogging in groupings G2‐G4, whereas Fitbits without HR had similar kcal estimates between level and inclined activities; this finding indicates that Fitbits with HR were responsive to a change in exercise intensity during inclined walking/jogging compared to level walking/jogging. For G1, estimated kcals were not different between sitting and standing but were significantly higher for cycling in all monitors. The increase in estimated kcal expenditure was much greater in the three Fitbits measuring HR (589–708% increase from sitting/standing to cycling) than in the two Fitbits without HR (90–139% increase from sitting/standing to cycling). However, mean absolute percent error for kcal predictions for Fitbits measuring HR (33.7–38.3%) were similar to Fitbits without HR (32.4–36.6%) overall and for most individual activities.

CONCLUSION

Fitbits measuring HR do use HR when predicting kcals during physical activity. However, kcal prediction accuracies were similarly poor compared to Fitbits not measuring HR. Individuals looking to use consumer‐based activity monitors to track kcal expenditure should do so cautiously.

Support or Funding Information

Alma College CORE Research Program

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Circadian Rhythm Does Not Alter the Sweating Response to Exercise in Thermoneutral and Warm Ambient Temperatures
Authors: Ravanelli Nicholas , Imbeault Pascal , Jay Ollie
Published: June 2021

The present study sought to determine whether the diurnal fluctuation in core temperature alters the sweating response to exercise in thermoneutral (23°C) and warm (33°C) environments. Six healthy males exercised on a semi‐recumbent ergometer at a fixed evaporative requirement for heat balance (200W/m2) for 60 min at two different times of day and two ambient temperatures matched for absolute humidity (1.3 kPa); i) 0800h/23°C, ii) 0800h/33°C, iii) 1600h/23°C, and iv) 1600h/33°C. Esophageal temperature (Tes), mean body temperature (Tb), local sweat rate (LSR) measured at the arm and upper back, and whole body sweat loss (WBSL) were measured. Resting absolute Tes was higher at 1600h compared to 0800h at 23°C (0800h: 36.7±0.2°C, 1600h: 36.9±0.2°C; P=0.04) and 33°C (0800h: 36.6±0.2°C, 1600h 36.9±0.2°C; P=0.005). Similarly, end‐exercise (steady‐state) absolute Tes was higher at 1600h relative to 0800h at 23°C (0800h: 37.4±0.2°C, 1600h: 37.6±0.2°C; P=0.04) and 33°C (0800h: 37.0±0.2°C, 1600h 37.2±0.2°C; P=0.01). However the change in Tes was similar irrespective of the time of day at both 23°C (0800h: 0.7±0.1°C, 1600h: 0.7±0.2°C; P=0.37) and 33°C (0800h: 0.4±0.1°C, 1600h: 0.3±0.1°C; P=0.35). Further, mean steady‐state LSR of arm and back after 60 min of exercise was similar irrespective of time at both 23°C (0800h: 0.66±0.06 mg/cm2/min, 1600h: 0.65±0.13 mg/cm2/min; P=0.74) and 33°C (0800h: 0.62±0.11 mg/cm2/min, 1600 h: 0.58±0.11 mg/cm2/min, P=0.50). Likewise, WBSL at steady‐state (46 to 60 min) was similar between morning and afternoon trials at 23°C (0800h: 156±28 g, 1600h: 162±36 g; P=0.38) and 33°C (0800h: 147±29 g, 1600h: 158±34 g, P=0.55). While sweating commenced prior to exercise in 33°C, the onset threshold for sweating occurred at a higher Tb at 1600h compared to 800h at 23°C (0800h: 35.6±0.1°C, 1600h 35.9±0.2°C; P=0.03), however the change in Tb was similar at 23°C regardless of time of day (0800h: 0.14±0.07°C, 1600h 0.17±0.12°C; P=0.47). Lastly, sudomotor thermosensitivity (LSR‐Tb) was similar at both 23°C (0800h: 0.80±0.26 mg/cm2/min/°C, 1600h: 0.82±0.30 mg/cm2/min/°C; P=0.80) and 33°C (0800h: 0.81±0.18 mg/cm2/min, 1600h: 0.90±0.40 mg/cm2/min, P=0.87). Taken together, preliminary data suggests the difference in absolute core temperature (~0.3°C) associated with diurnal fluctuation does not alter the sweating response at a fixed evaporative requirement for heat balance in both thermoneutral and warm conditions.

Support or Funding Information

N.R. was supported by an NSERC Postgraduate Scholarship‐Doctoral and a University of Ottawa Excellence Scholarship.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Crude oil impairs heart cell function in the mahi‐mahi (Coryphaena hippurus)
Authors: Heuer Rachael M. , Shiels Holly A. , Galli Gina L. J. , Cox Georgina K. , Stieglitz John D. , Benetti Daniel D. , Grosell Martin , Crossley Dane A.
Published: June 2021

The Deepwater Horizon oil spill of 2010 released millions of barrels of crude oil into the Gulf of Mexico. This was particularly concerning for many ecologically and economically important pelagic fish species, since the spill overlapped spatially and temporally with their spawning seasons. Pelagic fish have been shown to be sensitive to the cardiotoxic effects of oil across species, life stages, and levels of organization. Recent work on the mahi‐mahi (Coryphaena hippurus) has revealed that exposure to environmentally‐relevant crude oil concentrations negatively impacts animal performance, causing reductions to maximal sustained swimming speed and maximal metabolic rate. Subsequent in‐situ studies on the heart have revealed a ~40% reduction in cardiac output in oil‐exposed mahi, which explains reduced performance. Although cardiotoxic effects have been widely reported, the mechanisms underlying these impairments remain understudied. In the present study, we examined the impacts of crude oil on isolated mahi ventricular cardiomyocyte contractility to better understand these mechanisms. Contractility and other mechanical aspects of cellular contraction were measured using an IonOptix cell recording system, which uses sarcomere shortening as proxy for contractility. The first objective was to examine cardiomyocyte contractility over range of crude oil exposures. The second objective was to examine the impacts of crude oil contractility over a range of stimulation frequencies representative of heart rates observed in mahi (~100–180 beats per minute). Exposure to crude oil was found to significantly reduce heart cell contractile function, but was not found to be dose‐dependent in the range of tested concentrations (3.0, 6.4, and 12.9 μg l−1 ∑50 PAH). Crude oil was also found to impair contractility over a range of stimulation frequencies (1.5–3.0 Hz; 3.6 μg l−1 ∑50 PAH). Since the oil concentration needed to impair function at the cellular level was much lower than what has been observed to induce impairments to animal performance, the role of circulating catecholamines as a potential protective mechanism during oil exposure will also be explored. This research was made possible by a grant from The Gulf of Mexico Research Initiative. Grant No: SA‐1520

Support or Funding Information

Gulf of Mexico Research Initiative. Grant No: SA‐1520

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Relationship between Dietary Profile and Blood Glucose Concentration in Birds
Authors: Basile Anthony J. , Jarrett Catherine L. , Sweazea Karen L.
Published: June 2021

Diet throughout the life history of a species may contribute to their unique fuel physiology. Aves are unique in the animal kingdom as they evolved to have the highest plasma glucose (Pglu) concentration of any animal class. While Pglu is negatively correlated with body mass in Aves, there is considerable variation in Pglu among birds of similar body mass. A potential explanation for this variability may be dietary differences. Therefore, the goal of this study was to determine whether Pglu is related to diet profile (herbivore, omnivore, insectivore, frugivore/nectarivore, carnivore, granivore, and piscivore) within and across animal classes. Data on diet profile, Pglu, and body mass were obtained for 375 species of animals (Amphibia, n = 6; Aves, n = 163; Mammalia, n = 121, Reptilia, n = 85) housed at The Phoenix Zoo in Arizona. Data were analyzed using one‐way ANOVA and Dunn's post hoc analyses with p‐values of < 0.05 considered statistically significant. Data from captive animals are advantageous as the dietary profile and life history of each animal is known, thereby minimizing the unpredictability of wildlife. Consistent with prior studies, Aves maintained the highest Pglu among vertebrates (16.20 mM/L ± 0.26, p < 0.05). Within Aves, animals consuming either insectivorous or granivorous diets had the highest Pglu (p < 0.05). For insectivores, the high glucose concentrations are likely attributed to de novo hepatic and renal gluconeogenesis. Similarly, within Reptilia insectivorous animals maintain the highest Pglu (p < 0.05). No significant differences were found between dietary profile in Mammals (p > 0.05). Understanding the relationship between dietary profiles and Pglu may contribute to our understanding of why Aves evolved to have the highest glucose concentrations among vertebrates.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Chronic Fractalkine Administration Improves Glucose Tolerance with Improved Pancreatic Hormonal Profile in Obese Mice
Authors: Lee Yun Sok
Published: June 2021

Previously we reported that the fractalkine (FKN)/CX3CR1 system represents a novel regulatory mechanism for insulin secretion and beta cell function. In this study, we investigated whether chronic administration of a long acting form of FKN (FKN‐Fc) can exert durable effects to improve glucose tolerance in obese rodent models. Chronic FKN‐Fc administration markedly improved glucose tolerance with improved glucose‐stimulated insulin secretion and decreased beta cell apoptosis. Unexpectedly, chronic FKN‐Fc administration also decreased alpha cell glucagon secretion and decreased hepatic glucagon action. In pancreatic endocrine cells, FKN inhibited ATP‐sensitive potassium channel conductance by an ERK‐dependent mechanism, which potentiated glucose‐induced beta cell action potential (AP) firing and decreased alpha cell AP amplitude, leading to increased GSIS and decreased glucagon secretion. Beyond these islet effects, FKN‐Fc administration also enhanced hepatic insulin action and inhibited glucagon‐induced increased hepatic glucose output in obese insulin resistant mice. In hepatocytes, FKN treatment reduced glucagon‐stimulated cyclic AMP production and CREB phosphorylation in a pertussis toxin‐sensitive manner. Together, these results point to the potential use of FKN‐based therapy to improve Type 2 diabetes by increasing both insulin secretion and insulin sensitivity.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
T‐Cell Protein Tyrosine Phosphatase Restricts Intestinal Epithelial Cell Expression of the Oncogene Annexin A4
Authors: Krishnan Moorthy , Aftabizadeh Maryam , Yu Hua , McCole Declan F.
Published: June 2021

Phosphotyrosine‐based signaling is regulated by the balanced actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) to control various cellular processes including growth, differentiation, metabolism, and motility. Aberrant activation of signaling pathways by mutations and/or overexpression of PTKs and PTPs can lead to various types of cancers including colon cancer. Evolving evidence indicates that expression levels of PTPs, mainly protein tyrosine phosphatase non‐receptor type‐2 (PTPN2, protein product called T cell protein tyrosine phosphatase ‐TCPTP), PTPN22, and PTPN11 are altered in actively inflamed intestinal tissue. Loss‐of‐function single nucleotide polymorphisms (SNPs) in PTPN2 are associated with inflammatory bowel disease (IBD). The aim of this study was to determine if TCPTP functions as a tumor suppressor in intestinal epithelial cells (IEC). In this study, we used previously validated control shRNA and PTPN2 knockdown (PTPN2‐KD) HT‐29 IECs to determine if TCPTP loss affects oncogene expression. We performed proteomic analysis using mass spectrometry (MS) with Tandem Mass Tags (TMT) on PTPN2‐KD and control IECs. The most striking difference between control and PTPN2‐KD IECs was a 2.9 fold increase in the peptide count of Annexin A4 in PTPN2‐KD cells compared with control cells. Earlier studies indicated that Annexin A4 modulates membrane permeability, membrane trafficking, participates in cellular growth and apoptosis, enhances tumor invasion and promotes anti‐tumor drug resistance. To confirm the MS result, we performed RT‐PCR and Western blotting to determine if PTPN2 deficiency increased Annexin A4 mRNA and protein levels respectively. Both Annexin A4 mRNA and protein levels were significantly increased in PTPN2 KD IECs above control cells (221.5±2.4%, p<0.0001, 202±16.2 p<0.01 respectively). Immunofluorescence studies also revealed that Annexin A4 staining intensity was increased 1.5 fold in PTPN2 KD cells compared to control cells analyzed using ImageJ software. Annexin A4 expression in PTPN2‐KD IECs was further increased by IFN‐g treatment (1000 U/ml; 24 hrs). In summary, TCPTP deficiency leads to elevated expression of the tumor promoter, Annexin A4. These data suggest that loss‐of‐function mutations in the PTPN2 gene may increase pro‐tumorigenic factors that predispose to colorectal cancer.

Support or Funding Information

Supported by NIH 2R01DK091281 (DFM)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Diversity of ENaC expression in different tissues and different gender
Authors: Zhai Yujia , Zou Li , Linck Valerie , Chen Guangping , Ma He‐Ping
Published: June 2021

The epithelial sodium channel (ENaC) plays an important role in different organs such as kidney, lung, and colon. We performed Western blot experiments using the tissues from these organs of mice to determine whether ENaC expression is dependent on either tissue types or gender. Our data show that the kidney expressed more α‐ENaC than the lung and the colon whereas the lung expressed more β‐ and γ‐ENaC than the kidney and more γ‐ENaC than the colon. The diversity of ENaC expression may account for the different roles of ENaC in these organs. Our data also show that a 60 kD band was consistently detected with antibody to γ‐ENaC in the male mouse kidney, but barely seen in the female mouse kidney. The expression of this band was not altered by low sodium diet. It was also observed in cultured cortical collecting duct cells which were from the male mouse kidney. Interestingly, this band was not observed in the lung of any gender, but was the only band found in the colon of both male and female mouse. To determine whether this band represents a novel cleaved γ‐ENaC, we examined the enzymes that can cleave γ‐ENaC. The data show that the expression levels of prostasin, furin, kallikrein‐2, and plasmin were not significantly different between male and female, but the levels of prostasin was significantly different between the tissues of kidney and lung. These results suggest that there is a diversity of ENaC expression in different tissues and different gender. However, it remains to be further determined whether the 60 kD band represents a novel cleaved γ‐ENaC.

Support or Funding Information

NIH R01‐DK100582 to H.M.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Novel Loss‐of‐function Variants in the Epithelial Na+ Channel Extracellular Domain
Authors: Sheng Shaohu , Chen Jingxin , Wang Xueqi , Kleyman Thomas R.
Published: June 2021

Mutations in epithelial Na+ channel (ENaC) subunits cause hypertensive or hypotensive human diseases. Several genetic variants in ENaC genes are associated with high blood pressure or salt sensitivity. Certain ENaC variants reportedly serve as modifiers to diseases such as cystic fibrosis. In this study, we sought to identify loss‐of‐function human ENaC variants in a heterologous expression system. A total of 48 variants in extracellular domains of α and γ ENaC subunits were selected. Mutant α subunits were co‐expressed with wild type β and γ subunits whereas mutant γ subunits were co‐expressed with wild type α and β subunits in Xenopus oocytes. Amiloride‐sensitive currents measured by two‐electrode voltage clamp in cells expressing wild type and mutant ENaCs were compared to identify functional variants. Among the tested 24 αENaC variants, four (αH255R, αT274M, αG454V and αΔF528) showed significantly less currents than wild type channels (p< 0.001, n=16~26). Four out of 24 γENaC variants (γS134F, γN282S, γE314K and γW486X) also had significantly less currents than wild type channels (p < 0.05, n=16~30). To explore the underlying mechanisms for the loss‐of function phenotype, we examined Na+ self‐inhibition responses of the mutant channels. All four α (H255R, T274M, G454V and ΔF528) and one γ (E314K) mutants displayed significantly greater Na+ self‐inhibition responses than wild type channels, corresponding to lower open probabilities. Our results identify eight novel loss‐of‐function ENaC variants in the extracellular domain and suggest that five variants are ENaC gating modifiers.

Support or Funding Information

Supported by NIH DK079307, DK038470 and a DCI grant

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
DISTINCT EFFECTS OF GLUTATHIONE DISULFIDE ON δ‐ AND α‐EPITHELIAL SODIUM CHANNEL SUBUNITS
Authors: Coca Camila , Downs Charles , Wu Wei , Helms My
Published: June 2021

Background

Amiloride‐sensitive epithelial sodium channel (ENaC) is a membrane bound ion channel with selective inward permeability to Na. ENaC plays a critically important role in maintaining net fluid homeostasis. To date four ENaC subunits (α‐, β‐, γ‐, and δ‐ENaC) have been cloned in mammalian species. Mice, however, only express αβγ. In humans, an additional ENaC subunit (δ1) and its slice variant (δ2) have been recently identified. Unlike αβγ‐ENaC, the physiological role and regulation of channels made up of δ1 and δ2 subunits remain unclear.

Hypothesis

We tested the hypothesis that sodium channels containing α and δ ENaC subunits (alongside β and γ) are differentially regulated under oxidative stress.

Methods

Using the Xenopus laevis oocyte expression system, full‐length cDNAs for human ENaC subunits, and two electrode voltage clamp measurements, we modeled antioxidant depletion (a form of oxidative stress) and compared the effects of oxidized glutathione (GSSG) on αβγ‐ENaC and δβγ‐ENaC whole cell current. High extracellular GSSG treatments (400μM) increases the redox potential, and models antioxidant depletion in an oocyte expression system. This experimental approach allows for the singular study of αβγ vs. δβγ ENaC in a cell model system capable of normal assembly of multimeric ion channels into the membrane.

Results

GSSG significantly decreased ENaC activity in oocytes expressing αβγ‐ENaC (n=10). Conversely, GSSG significantly increased whole cell current in oocytes expressing δ1βγ‐ENaC (n=12) and in δ2βγ‐ENaC expressing oocytes (n=13) immediately upon extracellular exposure. While both α and δ ENaC subunits are directly modified by GSSG at Cys thiol sites, the effect and mechanism of GSSG posttranslational modification of α vs δ expressing Na channels differed significantly in our studies. Heterologous expression of αβR566Xγ ENaC in oocytes indicate that GSSG proteolytically degrades classical αβγ ENaC. Whole cell recordings and biotinylation studies indicate that δ2 ENaC subunits increase net Na transport via insertion of new membrane protein, whereas GSSG plays no role in δ1 transport and insertion into the cell membrane.

Conclusion

We found that αβγ ENaC activity is decreased by GSSG. Conversely δβγ ENaC activity is significantly increased by GSSG. This conclusion highlights the need to better understand the opposing translational effects of α vs δ ENaC subunits, as it may occur in human tissue. Additional studies are needed to better understand the molecular regulation and pathophysiological roles of α and δ ENaC subunits.

Support or Funding Information

Support for this project was made possible by the University of Utah Investigator Initiated Grant awarded to MNH.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Targeted activation of excitatory hM3Dq DREADD conditionally expressed in principal cells decreases ENaC activity to promote Na excretion.
Authors: Mironova Elena , Suliman Faroug , Berman Jonathan Max , Stockand James
Published: June 2021

The Epithelial Na+ Channel, ENaC, is the final arbiter of sodium excretion in the kidneys. As such, discretionary control of ENaC by hormones is critical to the fine‐tuning of electrolyte and water excretion and consequently, blood pressure. Local paracrine purinergic signaling intrinsic to the distal nephron inhibits ENaC activity via Gq‐coupled apical P2Y2 receptors. This purinergic signaling system functions in parallel with the renin‐AngII‐aldosterone system to maintain blood pressure. Loss of purinergic inhibition of ENaC causes salt‐sensitivity and elevated blood pressure. To further elaborate the cellular mechanisms and physiological consequences of local purinergic regulation of ENaC and to test whether stimulation of this inhibitory regulation of ENaC could ameliorate forced salt‐sensitivity in the DOCA‐salt mouse, we created an excitatory hM3Dq DREADD mouse with conditional expression of this synthetic receptor in principal cells. Activation of this DREADD receptor in these mice promoted renal Na+ excretion even under conditions, such as a Na+ free feeding regimen, that favored renal Na+ conservation. On‐going experiments test if this facilitation of Na+ excretion protects principal cell‐specific hM3Dq DREADD mice from elevations in blood pressure resulting from DOCA‐salt treatment.

Support or Funding Information

This research was supported by American Heart Association grants 15GRNT22930030 & 17GRNT3292002 (to JDS), and F32DK104572 (to EM).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Transpulmonary Pressure‐Dependent Regulation of Air Leaks after Peripheral Lung Injury
Authors: Servais Andrew B. , Valenzuela Cristian , Ysasi Alexandra , Wagner Willi , Kienzle Arne , Loring Stephen , Tsuda Akira , Ackermann Maximilian , Mentzer Steven
Published: June 2021

To assess the pathophysiology of pulmonary air leaks, we studied orotracheally intubated mice on mechanical ventilation with pleural injuries produced by a 25g needle inserted 1–2 mm into the lung parenchyma. The pleural injuries were studied using a standard inflation maneuver involving a 3 second ramp to 30 cmH20 followed by a 3 second breath hold. After pleural injury, the inflation maneuver resulted in a distinctive airway pressure time history; that is, peak inflation was followed by a rapid decrease to a lower plateau phase. The decay phase of the inflation maneuver was influenced by the injury area; the rate of pressure decline with multiple injuries (28+8 cmH20/sec) was significantly greater than a single injury (12+3 cmH20/sec)(p<.05). In contrast, the plateau phase pressure was independent of injury surface area, but dependent upon transpulmonary pressure. When the standard inflation maneuver was performed in a pressure‐regulated body box, the plateau transpulmonary pressures were a mean of 18+0.7 cm H2O regardless of the absolute pressures outside of the lung. Although the pleural injury resulted in a significant increase in delivered air volume (p<.01), there was no significant difference in air leak volume between 1 and 5 injuries (p>.05). These findings are consistent with the regulation of pleural air leaks by transpulmonary pressure‐dependent airway closure.

Support or Funding Information

NIH Grant HL94567, HL134229, HL007734, CA009535, ES000002 and the German Research Foundation (SFB1066)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Teaching New Words in New Ways: PhUn Week Outcomes in Elementary Students
Authors: Dickens Cameron M. , Crecelius Anne R.
Published: June 2021

Physiology Understanding (PhUn) week is organized by the American Physiological Society with the mission of promoting interaction between scientists and nonscientists, specifically through outreach to local schools to encourage science education. Elementary school students (n=27) from a local school participated in small group activities led by two undergraduate students, two graduate (masters) students, and a faculty member. The objectives of these activities were: 1) to teach basic physiological concepts, and 2) provide students an enjoyable, fun, and engaging hands‐on experience. Three separate lessons were created centering on the cardiovascular, respiratory, and muscular systems. Each lesson contained a short introduction, an individual small activity to illustrate the concept, and a larger demonstration indicative of laboratory activity. Students were given a worksheet for each station that highlighted important words related to the corresponding body system. After the completion of all 3 stations, elementary students completed a short worksheet. All three topics were evenly identified as the most interesting and fun. Less than half of the students reported being familiar with the term physiology before the event, and approximately 55% said they learned at least 3 new words over the course of the day. Students used a self‐reported 1–5 scale to assess their enjoyment (median=5) and learning (median=4). Free response answers identified key vocabulary used at the various stations (e.g. homeostasis, diaphragm). Overall, elementary students demonstrated an interest in physiology and laboratory methods when presented with this programming. Self‐reported data indicates this outreach activity was successful in achieving the intended objectives.

Support or Funding Information

Supported by the American Physiological Society and the Department of Health and Sport Science.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
‘An overview of the first year Undergraduate Medical Students Feedback on the Point of Care Ultrasound Curriculum’
Authors: Mohialdin Vian , Wainman Bruce , Shali Ari
Published: June 2021

With the technological progress of different types of portable Ultrasound machines, there is a growing demand by all health care providers to perform bedside Ultrasonography, also known as Point of Care Ultrasound (POCUS). This technique is becoming extremely useful as part of the Clinical Skills/Anatomy teaching in the undergraduate Medical School Curriculum.

Teaching/training health care providers how to use these portable Ultrasound machines can complement their physical examination findings and help in a more accurate diagnosis, which leads to a faster and better improvement in patient outcomes. In addition, using portable Ultrasound machines can add more safety measurements to every therapeutic/diagnostic procedure when it is done under an Ultrasound guide. It is also considered as an extra tool in teaching Clinical Anatomy to Medical students. Using an Ultrasound is one of the different imaging modalities that health care providers depend on to reach their diagnosis, while also being the least invasive method.

We thought investing in training the undergraduate Medical students on the basic Ultrasound scanning skills as part of their first year curriculum will help build up the foundation for their future career.

The research we report in this manuscript is a preliminary qualitative study. And provides the template for future model for teaching a hand on Ultrasound for all health care providers in different learning institutions.

A questionnaire was handed to the first year medical students to evaluate their hands on ultrasound session experience. Answers were collected and data was analyzed into multiple graphs.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Trabecular Bone Morphology in Hunter/Gatherer and Agricultural Populations
Authors: Palmer Jenna Elizabeth , Chirchir Habiba
Published: June 2021

According to the Law of Functional Adaptation, trabecular bone will adapt to loading placed on it by increasing in bone volume and changing its directionally. Previous studies show that there are differences that can be identified in trabecular bone morphology across populations with varied subsistence strategies. As the bone responds to mechanical loading, that relationship has been shown to be complex. Consequently, it is necessary to consider diverse populations with varied subsistence strategies in order to have a complete understanding of changes in trabecular bone morphology. Therefore, this study's goal is to identify differences in trabecular bone volume in two hunter‐gatherer populations and one farming population derived from South Africa, Egypt, and Australia. The South African populations were (n=6) in populations from Khoisan, Korana, and Morolong. Populations from Australia were (n=6) who are indigenous Aboriginals. The sedentary farming population sample size was (n=8) from El‐Hesa in Egypt.

This study predicts that because hunter‐gatherers engage in greater activity levels due to greater travel distances, they will exhibit greater trabecular bone volume. The agricultural group with a more sedentary lifestyle will have a lower bone volume due to presumed lower levels of activity among later agricultural societies. To test this prediction, trabecular bone volume in two limb elements (the femoral and humeral heads) was estimated using micro‐CT scanning. The Quant3D program is used to quantify trabecular bone volume fraction (BV/TV – bone volume/total volume) and we used Mann‐Whitney‐Wilcoxon test to identify the differences in BV/TV in the two populations.

Interestingly, preliminary results show BV/TV is not significantly different in two populations in both upper (humerus) and lower (femur) limb elements. Although these results derive from a pilot study, they suggest caution in interpretation of the effect of mechanical loading on trabecular bone. We intend to expand and increase the sample sizes to include more limb elements to further explore variation in trabecular bone volume within these and more populations.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
N‐3 fatty acids prevent trabecular bone loss
Authors: Sanchez Diego , Mendez Daisy , Fernandes Gabriel , Banu Jameela
Published: June 2021

N‐3 fatty acids have been implicated in preventing bone loss. Whether n‐3 fatty acids can restore bone loss is not established. We conducted a study using the ovariectomized mouse model to determine if n‐3 fatty acids can restore bone.

Ten months old, C57BL/6, retired breeder mice were either sham operated or ovariectomized and left for 3 months. The different groups were: Group 1. LC S; Group 2. LC O; Group 3. 18/12 S; Group 4. 18/12 O Group 5. 30/20 S Group 6. 30/20 O. Mice were fed either LC or FO (10%). The LC and FO fed groups were kept in the respective diet regimens for the next 3 months, at the end of which they were sacrificed and long bones were subjected to pQCT analyses.

In the distal femoral metaphysis, trabecular bone mineral content (Tb BMC) was decreased significantly in the LC O mice while it was increased in the 18/12 O group. Similarly in the proximal tibial metaphysis, the Tb CNT and cortical bone mineral content were significantly higher in the 18/12 O and 30/20 O groups.

In summary, the 18/12 n‐3 fatty acids increased trabecular content in both the femur and tibia and the cortical BMC was increased only in the tibia, suggesting that 18/12 is more beneficial.

Support or Funding Information

Funding: Engaged Scholarship for Undergraduate Research.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A Novel Idea in the Use of Ultrasound to Guide Nasolabial Hyaluronic Acid (HA) Dermal Filler Injections to Prevent Alar Nasal Necrosis
Authors: Klubowicz Dorota Maria , Vissa Deepti , Johnson Marjorie , Barbeau Michele , Khalil Andrew , Martin Charys , Merrifield Peter , Perinpanayagam Hiran , Galil Khadry
Published: June 2021

Background

Nasolabial dermal filler (DF) injections are one of the most popular cosmetic procedures performed worldwide. DF injections at the nasolabial fold have been associated with nasal necrosis due to inadvertent intravascular injection of the adjacent facial artery (FA). Current DF injection protocols are devoid of imaging the anatomical site, and the use of ultrasound (US) for imaging the FA is very limited in literature. The purpose of this study is to determine the feasibility of utilizing US to identify and measure the FA at different bony landmarks near and within the nasolabial region.

Methods

Part I

Cadaveric dissections (n=18; 10 female, 8 male) will be completed to explore the course of the FA from the external carotid artery to the terminal branches supplying facial structures.

Part II

A bilateral US of the FA using 13–6 MHz, 38 mm linear array US transducer was performed on consenting adults (n=16; 9 female, 7 male) from the Department of Anatomy and Cell Biology at Western University. The following bony landmarks were identified and used for US measurements, taken in real time: anterior‐inferior angle of the mandible, mandibular teeth, maxillary teeth, maxillary ridge. Measurements of FA diameter, artery distance to skin, and artery distance to bone were obtained at each landmark using digital image distance measurements on the Sonosite M‐Turbo P08189‐88R US machine.

Results

Part I

Preliminary results (n=8; 4 female, 4 male) show FA variability between cadaveric specimens, as well as left/right FA variability within cadaveric specimens themselves.

Part II

Preliminary results of the average FA distance to the skin measured at 0.438 cm ± 0.126 for the left FA and 0.459 cm ± 0.205 for the right FA. A significant difference (P< 0.05) was noted for FA distance to the skin between the left mandibular teeth (0.481 cm ± 0.107) and left maxillary ridge (0.343 cm ± 0.097).

Conclusions

These findings highlight the importance of understanding the anatomy of the FA within the nasolabial fold, and the need to carefully personalize the placement of DF injections, due to the anatomical variability identified in both the cadaveric and ultrasound portions of the study. Furthermore, since it is feasible to identify and measure the FA using the selected US transducer, the future direction of this study will be to examine the application of US to guide DF injections.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.