bluuebunny/crossref_metadata_2025 huggingface dataset:
Urinary Markers of Kidney Injury in Chronic Kidney Disease Patients Following 12 Weeks of Exercise Training
Authors: Patik Jordan C. , Kirkman Danielle L. , Guderian Sophie , Edwards David G.
Published: June 2021

It is well established that individuals with chronic kidney disease (CKD) have diminished cardiorespiratory fitness compared to age‐matched healthy individuals and this deficit in fitness is associated with worsened clinical outcomes. As such, exercise training is recommended as an adjunct therapy for a myriad of health benefits in this population. However, further investigation is warranted into the effects of exercise training on kidney health and function in CKD. Therefore, the purpose of this trial was to investigate the effects of 12 weeks of moderate‐vigorous intensity aerobic training on urinary markers of kidney injury, kidney injury molecule 1 (KIM‐1) and neutrophil gelatinase‐associated lipocalin (NGAL). Twenty‐four stage 3 and 4 CKD patients (age: 59 ± 12 yr; eGFR: 43 ± 12 mL/min/1.73m2) were randomly allocated to exercise training (EXT, n=13) or a sedentary control condition (CON, n=11) for 12 weeks. EXT participated in 45 min of individually supervised aerobic activity 3 times per week at 60–85% of heart rate reserve while CON received routine care. Outcome measures were assessed at baseline and following 12 weeks. VO2peak was assessed with a 15 watt/min ramp protocol on a cycle ergometer. Urinary KIM‐1 and NGAL were assessed with commercially available ELISA kits and concentrations of each were normalized to urine creatinine concentration. Groups were matched for age, BMI, and eGFR. Following 12 weeks, EXT showed an increase in VO2peak compared to CON (P<0.05). There was not a significant time by condition interaction for urinary KIM‐1 (Baseline vs. Post; CON: 9 ± 4.3 vs 11.9 ± 7.7 ng/mgCr; EXT: 14.2 ± 20.2 vs 15.1 ± 21.5 ng/mgCr, P=0.84). Likewise, NGAL was also unchanged by time or condition (Baseline vs. Post; CON: 207.8 ± 301.7 vs 281 ± 356.5 ng/mgCr; EXT: 126.5 ± 190.5 vs 262.8 ± 459.7 ng/mgCr, P=0.65). These results indicate that moderate – vigorous intensity aerobic exercise improves cardiorespiratory fitness in CKD patients, and does not increase markers of kidney injury as measured by urinary KIM‐1 or NGAL. These data demonstrate that moderate to vigorous aerobic exercise is safe for CKD patient in terms of acute kidney injury.

Support or Funding Information

This research was supported by National Heart, Lung, and Blood Institute Grant HL‐113514.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Role of Fasting Interventions on Skeletal Muscle in High Fat Diet Fed Mice
Authors: Puppa Melissa , Persinger Aaron , Brown Katie , Wible Ryan , Sharma Sunita , Smith Nicholas , Caldwell Jade , van der Merwe Marie , Bloomer Richard
Published: June 2021

Obesity is a growing epidemic worldwide leading to growing rates of chronic disease and diabetes. A diet rich in omega‐6 fatty acids and refined sugars, known as the “Western diet,” may be one contributing factor. Prevention of weight gain, as well as weight loss, have been shown to be beneficial in preventing obesity‐associated chronic disease. Growing evidence suggests that fasting may be a reliable method to aid in weight loss and prevention of weight gain. Although fasting is effective in reducing fat mass, there is a risk of losing lean muscle. There are many different types of fasting, including time restricted feeding and alternate day fasting. Little is known about the effects of these types of fasts on skeletal muscle while continuing to consume a high fat diet. The purpose of this study was to examine the effects of different types of fasts on skeletal muscle while continuing to consume a high fat diet. Mice were fed a high fat diet (45% fat, mostly lard) for 6 weeks while a subset of mice consumed a standard chow diet. At the end of 6 weeks, chow mice continued with ad libitum access to chow food, while the remaining mice that were on the high fat diet were divided into one of the following groups: ad libitum high fat diet (HFD), ad libitum standard chow (SC), purified refined diet ad libitum (PD), caloric restriction to 80% of ad libitum high fat consumption (CR), 6h of ad libitum time restricted feeding on high fat diet (TRF), and alternate days of ad libitum feeding on high fat diet and fasting (ADF). Mice were kept on their respective diets for 8 additional weeks and were euthanized at the end of the study and hindlimb muscles were weighed and snap frozen for analysis. HFD mice gained more fat mass than the fasting groups p<0.001. There was no significant difference in hindlimb muscle mass normalized to tibia length across all groups; however, in relation to body weight, HFD mice had significantly less muscle mass. ADF (p<0.001) and TRF (p<0.001) preserved muscle mass in relation to body weight. Muscle IGF‐1 mRNA expression was decreased with HFD. ADF was unable to attenuate the decrease; however, changes in the composition of the diet with DF attenuated the decreased IGF‐1 expression. These data support the use of various fasting interventions in obesity to prevent muscle mass loss while still losing adipose mass.

Support or Funding Information

University of Memphis School of Health Studies

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Reduced Extracellular [Ca2+] Increases the Sensitivity of Mouse EDL and Soleus to the K+‐Induced Force Depression: Implication for the Increased Sensitivity of Hyperkalemic Periodic Paralysis Muscles to Calcium Levels
Authors: Renaud Jean‐Marc , Uwera Francine
Published: June 2021

Hyperkalemic periodic paralysis (HyperKPP) is a disease of altered skeletal muscle excitability due to missense mutations in the skeletal muscle Na+ channel (NaV1.4). It is primarily characterized by myotonic discharges between and during periods of paralysis that mainly affect limb muscles. The paralysis is induced by large membrane depolarizations associated with the increase in Na+ influx and accumulation of extracellular [K+] during the myogenic discharge. Patients can be alleviated of their paralysis by taking salbutamol and/or ingesting Ca2+. While salbutamol mechanism of action involves an improved resting membrane potential and an increase in Ca2+ release, the effect of Ca2+ is not well understood except that a large increase in extracellular [Ca2+]e ([Ca2+]e) reduces the K+‐induced force depression. The objective of this study was therefore to test the hypothesis that a reduced [Ca2+]e increases the extent of the K+‐induced force depression and reduces the salbutamol‐induced increase in force at elevated [K+]e. A decrease in [Ca2+]e from 2.4 mM to 0.3 mM had no effect on the tetanic force of both wild type mouse EDL and soleus when [K+]e was at the normal 4.7 mM. However, it significantly shifted the tetanic force‐[K+]e relationship to lower [K+]e. At 2.4 mM Ca2+ and 4.7 mM K+, HyperKPP EDL and soleus generated as much tetanic force as their wild type counterpart. However, decreases in [Ca2+]e to 1.3 and 0.3 mM significantly reduced tetanic force at 4.7 mM and caused large and significant shift of the tetanic force‐[K+]e relationship to lower [K+]e. Lowering [Ca2+]e did not affect the efficacy of salbutamol to increase tetanic force when it had been depressed by an increase in [K+]e in either wild type or HyperKPP muscles. Considering that at 4.7 mM K+, several HyperKPP EDL and soleus fibers are depolarized and that the effect of lower [Ca2+]e occurred when the cell membrane is depolarized by increases in [K+]e, it is suggested that the increased sensitivity of HyperKPP muscles to Ca2+ is primarily because of a large number of fibers with depolarized cell membrane even when [K+]e is at its normal value of 4.7 mM.

Support or Funding Information

This study was supported by the Canadian Institute of Health Research (CIHR)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intracerebroventricular Administration of Fibroblast Growth Factor Receptor Inhibitor Attenuates High‐Phosphate Diet‐Induced Exercise Pressor Reflex Overactivation in Rats
Authors: Kim Han‐Kyul , Mizuno Masaki , Iwamoto Gary A. , Ishizawa Rie , Mitchell Jere H. , Smith Scott A. , Vongpatanasin Wanpen
Published: June 2021

Inorganic phosphate (Pi) is used extensively as a preservative and a flavor enhancer in the Western diet. As a result, dietary Pi intake in the US far exceeds the recommended daily allowance. A previous study from our laboratory has demonstrated that dietary Pi excess induces an exaggerated rise in blood pressure and renal sympathetic nerve activity (RSNA) in response to muscle contraction. This augmented pressor response was further shown to be mediated by an exaggerated skeletal muscle exercise pressor reflex (EPR). However, the underlying mechanism responsible for the EPR overactivity observed remains unknown. Fibroblast growth factor (FGF) 23 is one of the principle hormones involved in Pi homeostasis. It can cross the blood brain barrier and activate FGF receptors in the brainstem. The purpose of this study was to test the hypothesis that Pi‐induced EPR overactivity is mediated by brain FGF receptor stimulation. Sprague‐Dawley rats were fed a normal Pi (NP) diet containing 0.6% Pi (n=13) or a high Pi (HP) diet containing 1.2% Pi (n=13) for three months. Subsequently, mean arterial pressure (MAP) and RSNA responses to EPR activation were measured in decerebrate NP and HP animals. MAP and RSNA measures were obtained before and after intracerebroventricular (ICV) administration of the FGF receptor inhibitor PD173074. ICV PD173074 administration significantly reduced the exaggerated MAP (Δ=35±4 vs. 9±2 mmHg, P<0.01) and RSNA responses (Δ=84±16 vs. 32±7 %, P<0.01) to electrically induced hindlimb muscle contraction via ventral root stimulation (i.e. EPR activation) in the HP group, but did not significantly affect the responses in the NP group (ΔMAP =18±3 vs. 13±2 mmHg, ΔRSNA=40±10 vs. 30±7 %). MAP and RSNA responses to intra‐arterial infusion of capsaicin in the hindlimb (designed to assess the metabolically‐sensitive component of the EPR) were also attenuated by PD173074 in HP rats (ΔMAP=43±4 vs. 24±5 mmHg, ΔRSNA=98±25 vs. 48±9 %, P≤ 0.02) but remained unchanged in NP animals (ΔMAP=32±4 vs. 34±4 mmHg, ΔRSNA=61±12 vs. 66±18 %). The findings suggest that stimulation of FGF receptors in the brain contributes significantly to the generation of exaggerated EPR activity after excess Pi consumption. Moreover, the data demonstrate a novel action of central FGF receptor inhibition by reversing the EPR overactivity manifest in animals fed a high Pi diet. Importantly, the results implicate dietary Pi as a potential therapeutic target for the prevention and/or treatment of abnormally large sympathetic and blood pressure responses to exercise.

Support or Funding Information

NIH 5RO1HL133179‐02

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Heat treatment attenuates the exaggerated exercise pressor reflex in rats with peripheral artery disease
Authors: Xing Jihong , Lu Jian , Li Jianhua
Published: June 2021

Femoral artery occlusion in rats has been used to study human peripheral artery disease (PAD). The responses of blood pressure (BP) and sympathetic nerve activity are exaggerated during static exercise in PAD rats with femoral artery occlusion. The purpose of the current study was to examine if heat treatment (a prior heat exposure) has beneficial effects on the exaggerated exercise pressor reflex in PAD rats. Basal muscle temperature (Tm) was 35.6±0.1 °C in control rats (n=3); and 34.2±0.1 °C in PAD rats (n=5; P<0.05 vs. control rats). As Tm was increased by ~1.5 °C and this was maintained for 30 min, core temperature was not altered in control group and PAD group. The heat treatment was performed 2 times daily for 3 days. Then we examined the BP response to static muscle contraction. The greater mean arterial pressure (MAP) response was observed in PAD rats (31±5 mmHg in PAD rats/n=6 vs. 22±3 mmHg in control rats/n=8; P<0.05). Heat treatment attenuated amplification of BP response in PAD rats (MAP response: 24±3 mmHg in PAD rats with heat treatment/n=5; P<0.05 vs. no heat treatment). Note that no significant difference in developed muscle tension during muscle contraction was seen in control rats and PAD rats with heat treatment or without heat treatment (P>0.05). Our data support the hypothesis that a prior heat exposure plays an inhibitory role in modifying exaggeration of the exercise pressor reflex in PAD.

Support or Funding Information

NIH P01 HL134609

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Evidence of a Shear Stress Stimulus Profile Dependent Impact of Cycling Training on Flow‐Mediated Dilation
Authors: King Trevor James , Pyke Kyra
Published: June 2021

Lower limb endurance training can improve conduit artery flow‐mediated dilation (FMD) in response to transient increases in shear stress (reactive hyperemia; RH‐FMD) in both the upper and lower limbs. Sustained increases in shear stress recruit a partially distinct transduction pathway and elicit a physiologically relevant FMD response that appears to provide distinct information regarding endothelial function (sustained shear stress‐FMD, SS‐FMD). However, the impact of training on SS‐FMD is not well understood.

PURPOSE

To determine the impact of cycling training on handgrip exercise induced brachial artery (BA) FMD (BA SS‐FMD) and calf plantar‐flexion induced superficial femoral artery (SFA) FMD (SFA SS‐FMD).

METHODS

28 young males were randomized to control (n=12) or training (n=16) groups. Participants in the training group cycled 30 min/day, 3 days/week for 4 weeks at 80 % heart rate reserve. RH‐FMD and SS‐FMD was assessed in the BA and SFA pre and post‐intervention via Duplex ultrasound.

RESULTS

Data are mean ±SD. Training did not impact SS‐FMD in either artery, and RH‐FMD in the SFA was also unchanged (p>0.05). When controlling for the shear rate stimulus via covariate analysis, BA RH‐FMD improved in the training group (p=0.05) (Control: pre‐ 5.7 ± 2.4%, post‐ 5.3 ± 2.4%; training: pre‐ 5.4 ± 2.5%, post‐ 7.2 ± 2.4%).

CONCLUSIONS

Endurance training resulted in non‐uniform adaptations to endothelial function, with an isolated impact on the brachial artery, and on the ability to transduce a transient increase in shear stress.

Support or Funding Information

Funded by NSERC

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Breast Cancer Survivors Improved Forearm Blood Flow Following a Single Bout of Aerobic Exercise: Preliminary Results
Authors: Grigoriadis Georgios , Hibner Brooks A. , Schroeder Elizabeth C. , Rosenberg Alexander J. , Danciu Oana C. , Fernhall Bo , Baynard Tracy
Published: June 2021

Chemotherapy impairs endothelial and resistance artery function contributing to arterial dysfunction, a cardiovascular disease (CVD) risk factor. In healthy individuals, a bout of aerobic exercise acutely improves arterial function. However, the acute effect of aerobic exercise on resistance artery function has not been examined in breast cancer survivors (BCS).

PURPOSE

To examine the effect of a single bout of aerobic exercise on forearm blood flow in BCS.

METHODS

Seven BCS (48 ± 4 yrs; 26.0 ± 2.8 kg/m2), 1–5 year post‐chemotherapy treatments and eight female controls (44 ± 9 yrs; 24.2 ± 5.3 kg/m2) completed 30 minutes of cycling exercise at 65% of their maximal aerobic capacity. Cardiac output (Q), Heart rate (HR), mean arterial pressure (MAP), and forearm blood flow (FBF) were assessed at baseline, 15 and 45 minutes post exercise. Automated ambulatory blood pressure monitor was used to acquire Q, HR, and MAP. FBF and Peak FBF was measured with strain‐gauge plethysmography at rest and following 5 minutes of upper arm occlusion respectively. Reactive hyperemia was calculated as the change between baseline and peak FBF. Area under the curve was calculated by including 13 measurements after the 5 min occlusion. Conductance was estimated as FBF divided by mean arterial blood pressure.

RESULTS

See Table. In BCS and control groups baseline FBF and conductance increased 15‐min post‐exercise and returned to baseline at 45 minutes post exercise (p<0.05). MAP decreased at 45‐min post‐exercise in both groups (p<0.05). HR was elevated at 15‐min and 45‐min in both groups (p<0.001), while BCS had an overall higher HR (p<0.05). There were no changes in peak FBF, reactive hyperemia area under the curve, peak conductance and Q following exercise.

CONCLUSION

Baseline forearm blood flow increased in breast cancer survivors following a single bout of aerobic exercise likely as a result of acute forearm vasodilation. In addition, breast cancer survivors did not exhibit differences at baseline or following exercise suggesting that arterial function was preserved 1–5 years following chemotherapy.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Age‐dependence of Methylation, Transsulfuration and Glutathione Synthesis Pathways in Human Frontal Cortex
Authors: Deth Richard , Schrier Matthew , Dong Jianan , Lemle Marian , Trivedi Malav
Published: June 2021

Neuronal synthesis of the antioxidant glutathione (GSH) depends upon availability of cysteine, provided either by cellular uptake or by transsulfuration of homocysteine generated by the methionine cycle of methylation (Fig. 1). To evaluate age‐dependent changes in the relative contribution of these two cysteine sources, we measured redox and methylation metabolite levels in postmortem human frontal cortex from subjects across the lifespan. Levels of the transsulfuration intermediate cystathionine were significantly decreased in 60–80 yr‐old subjects, indicating that the balance between these two cysteine sources shifts to transsulfuration in older age. This shift was accompanied by decreased methionine and S‐adenosylmethionine, and an increase in homocysteine, indicating lower activity of the folate and B12‐dependent enzyme methionine synthase (MS), consistent with earlier finding of decrease MS expression with age. Cystathionine levels in 10 yr‐old autistic subjects were decreased, similar to those of 60 yr‐old subjects. In vitro studies with human neuronal cells showed that the pro‐inflammatory cytokine TNF‐alpha increased transsulfuration and inhibited MS activity in association with decreased cysteine uptake. Transsulfuration pathway enzymes cystathionine beta synthase (CBS) and cystathionine gamma lyase (CGL) both produce hydrogen sulfide, which inhibits oxidative respiration and increases glycolysis. This action decreases production of reactive oxygen species (ROS), limiting the demand for antioxidant. Together these observations illustrate how an age‐dependent increase in transsulfuration links antioxidant synthesis to methylation status in human brain. TNF‐alpha, whose levels increase with age, may be a regulator of transsulfuration, with important implications for epigenetic regulation during early brain development.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Increased Mitochondrial ROS Generation from Complex III Causes Mitochondrial Damage and Increases Endoplasmic Reticulum Stress
Authors: Chen Qun , Allegood Jeremy C. , Thompson Jeremy , Toldo Stefano , Lesnefsky Edward J.
Published: June 2021

Rationale

Mitochondrial dysfunction contributes to greater susceptibility to injury from superimposed disease in the aged heart. Aging decreases complex III activity and increases ROS production from complex III. Oxidative stress from mitochondria can trigger endoplasmic reticulum (ER) stress.

Objective

To study the contribution to additional mitochondria dysfunction and ER stress from Complex III generated ROS.

Methods

Antimycin A (AA) (0.4mg/kg i.p.), a complex III inhibitor that increases ROS, was given to adult C57/bl/6 mice and function (echo), mitochondria function and ER stress assessed after 48 hrs.

Results

Low dose in vivo AA led to only mild cardiac dysfunction and no inhibition of respiration through complex III (succinate respiration). AA decreased complex I activity and respiration (glutamate+malate). ER stress increased shown by greater CHOP (transcription factor C/EBP homologous protein) expression (Figure). Susceptibility to mitochondria permeability transition pore (PTP) opening was increased as shown by decreased calcium retention capacity.

Conclusion

Increased ROS from complex III damages complex I and increases ER stress with greater PTP susceptibility, mechanisms of enhanced injury observed in the aged heart with superimposed disease including ischemia and reperfusion.

Support or Funding Information

This work was supported by the Office of Research and Development, Medical Research Service Merit Review Award (2IO1BX001355‐01A2) and Department of Veterans Affairs (EJL); National Institutes of Health NIH R21AG054975‐01 (QC).

Vechile(n=6)
AA(n=5)

Cardiac output/beat (ul)
40±2
29±2*

Oxidative phosphorylation (nAO/min/mg protein) Glutamate+malate
388±14
332±10*

Succinate
531±32
538±20

Complex I (mU/mg protein)
841±61
612±38*

Calcium Retention Capacity (nmol calcium/mg protein)
1033±56
848±52*

Mean ± SEM:

p<0.05 vs. Vechicle.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mitochondrial ultrastructure, function, and calcium buffering by massive calcium loading observed using advanced cryo‐electron microscopy, high‐resolution respirometry and spectrofluorimetry
Authors: Strubbe Jasiel Omil , Schrad Jason , Parent Kristin N , Conway James , Bazil Jason N
Published: June 2021

Excessive calcium accumulation is the main cause of cardiac tissue and cell death after a myocardial infarction. As a result of calcium overload, mitochondria become dysfunctional, produce excessive reactive oxygen species (ROS), cannot support the cellular energetic demand, and activate the cyclosporine A‐sensitive mitochondrial permeability transition pore. To discern the molecular, bioenergetic, and structural events associated with this phenomenon, we collected and analyzed a time‐course series of images obtained by utilizing recent advances in electron cryo‐microscopy methods. Energized mitochondria exposed to high calcium boluses, sufficient to elicit mitochondrial permeability transition, resulted in the formation of calcium phosphate granules. Under high calcium loading, the size of the calcium‐phosphate granules ranged from 50–120 nm causing OMM/IMM rupture. CsA treatment resulted in mitochondria with aberrant morphologies, increased cristae density and number, and with larger calcium‐phosphate granules ranging from 40–200 nm. The OMM was partially or completely lost; however, the mitochondria were fully functional and capable of synthesizing ATP. Our tomographic reconstruction placed these granules in close vicinity to the IMM and cristae. In addition, CsA treatment increases the calcium buffering power at greater calcium concentrations, whereas untreated mitochondria had much lower calcium buffering. Our results demonstrate that these granules form an intricate part of the mitochondrial calcium sequestration system. Overall, these results suggest CsA may interact with IMM components to: 1) modulate calcium buffering by facilitating more abundant and larger calcium phosphate granules and 2) preserve the cristae shape and number which avoids cytochrome c loss and mitochondrial permeability transition. Our data reveal that drugs capable of modulating cristae shape and number may be an effective strategy to prevent mitochondrial dysfunction stemming from calcium overload.

Support or Funding Information

This work was supported by NIH grant R00‐HL121160.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Targeting of reactive isolevuglandins in mitochondrial dysfunction and inflammation
Authors: Mayorov Vladimir , Uchakin Peter , Amarnath Venkataraman , Dikalova Anna , Panov Alexander , Zackert Bill , Davis Sean , Dikalov Sergey
Published: June 2021

Inflammation is implicated in cardiovascular diseases, acute kidney injury, lung and heart failure, which represent major causes of morbidity and mortality in Western Societies. Despite use of multiple drugs, both chronic and acute inflammation is still remaining a major health burden. Inflammation produces highly reactive dicarbonyl lipid peroxidation products, isolevuglandins (isoLG) which reacting with lysine residues of proteins covalently modify and cross‐link proteins. Mitochondrial dysfunction has been associated with inflammation; however, its pathophysiological role and molecular mechanisms are still obscure. We propose that inflammation‐induced mitochondrial isoLG play a key role in mitochondrial dysfunction and mortality. To test this hypothesis, we have (a) investigated the mitochondrial dysfunction in response to synthetic isoLG and isoLG adducts; (b) developed new mitochondria‐targeted isoLG scavenger mito2HOBA by conjugating the lipophilic cation triphenylphosphonium to 2‐hydroxybenzylamine; (c) tested if mito2HOBA protects from mitochondrial dysfunction and mortality using LPS model of inflammation. Acute isoLG exposure of mitochondria or treatment with low‐molecular isoLG adducts with lysine, ethanolamine or phosphatidylethanolamine inhibits mitochondrial respiration and attenuates Complex I activity while complex II function is much more resistant to isoLG. To test the pathophysiological role of mitochondrial isoLG we have studied therapeutic potential of mito2HOBA. We have confirmed that mito2HOBA vividly accumulates in isolated mitochondria and it is highly reactive with isoLG compared with untargeted 2HOBA. In vivo studies of isoLG‐mediated mitochondrial dysfunction in mouse LPS model showed that mito2HOBA supplementation in drinking water (0.1 g/L) increased animals survival by 3‐fold and improved complex I‐mediated respiration. These data unambiguously support the role of mitochondrial isoLG in mitochondrial dysfunction in inflammation. We conclude that mitochondrial isoLG can be a promising therapeutic target in inflammation and conditions associated with mitochondrial oxidative stress and dysfunction.

Support or Funding Information

Navicent Health Foundation; NIH/NHLBI 1R01HL124116

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Neprilysin colocalizes with the V‐ATPase in kidney A‐type intercalated cells: possible role in urinary acidification
Authors: Bouley Richard , Muhsin Saif , Hong Wei Yan , Nair Anil , Cheung Pui , Brown Dennis
Published: June 2021

Intercalated cells (IC) in kidney collecting ducts are essential for acid‐base homeostasis. A proteomic analysis of these cells after purification by FACS revealed unexpectedly that they express high levels of neprilysin, a neutral protease, previously reported to be located in the brush border of proximal tubule cells. Therefore, we re‐examined the distribution of neprilysin in the kidney by immunohistochemistry and western blot analysis. Using anti‐neprilysin antibodies and two collecting duct markers: anti‐AQP2 antibody (principal cells) and anti‐A1 subunit v‐ATPase subunit (intercalated cells), we found that neprilysin was detectable not only in the proximal tubule, but also in ICs (but not principal cells) in all regions of the collecting duct. A similar distribution of neprilysin was seen in both mouse and rat kidneys. We then used an anti‐pendrin antibody to identify B‐type ICs in cortical collecting ducts. Only 35% of IC‐B population express neprilysin. Western blot analysis using an antibody against neprilysin showed that both cortical and medullary membrane preparations expressed neprilysin, and that female mice express more neprilysin than males in the cortex. However, this sex difference is not present in the medullary preparation, and we, therefore, attribute it mainly to a difference in proximal tubule expression. A similar result was observed in the kidneys of knockout mice that lack the IC‐specific B1 subunit of the V‐ATPase. In order to study the potential role of neprilysin in renal physiology, we treated male mice for 3 days with thiorphan, a selective neprilysin inhibitor. We measured a slight reduction of urine osmolality 1851 ± 160 to 1357 ± 240 (p=0.12) and an increase in urine volume 0.86 ± 0.21 to 1.48 ± 0.50, p= 0.23). In contrast, the change in urine pH was significant, increasing from 6.6 ± 0.1 to 6.9 ± 0.1, (n=3, p= 0.029) with the inhibitor, suggesting a role of neprilysin in acid excretion, possibly via IC function and V‐ATPase activity. In summary, we found that neprilysin is highly expressed in A‐ICs, where it colocalizes with the V‐ATPase. Its expression is higher in female mice, and it may have an as yet undetermined role in renal acid excretion.

Support or Funding Information

This work was supported by National Institutes of Health (NIH) grant DK096586 (D. Brown). The Zeiss LMS 800 confocal system in the Program in Membrane Biology (PMB) Microscopy Core was purchased using an NIH Shared Instrumentation Grant S10 RR031563‐01 (DB).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Differential regulation of vacuolar H+‐ATPase subunits by Transforming Growth Factor beta 1 (TGF‐β1) in salivary ducts
Authors: Roussa Eleni , Kluge Milena , Namkoong Eun , Park Kyungpyo
Published: June 2021

Bicarbonate concentration in saliva is controlled by the action of acid‐base transporters in salivary duct cells. We have previously shown expression of ATP6V1E1 and ATP6V1A in human and rodent salivary ducts and adaptive redistribution to the apical plasma membrane following acute and chronic metabolic acidosis. However, whether such redistribution has any physiological significance has not been elucidated. Using the human submandibular gland cell line HSG, we show for the first time functional expression of V‐ATPase in submandibular duct cells and introduce Transforming Growth Factor beta (TGF‐β) as a novel regulator of V‐ATPase subunits. Using QRT‐PCR, immunoblotting, biotinylation of surface proteins, immunofluorescence, and intracellular H(+) recording with H(+) ‐sensitive dye 2′,7′‐bis‐(carboxyethyl)‐5‐(and‐6)‐carboxyfluorescein, we show that activation of TGF‐β signalling upregulates ATP6V1E1 and ATP6V1B2, and has no effect on ATP6V1A. Following acidosis, neutralization of TGF‐βs or blocking of Smad2/3 phosphorylation decreased membrane expression of ATP6V1A, and prevented the acidosis‐induced increased V‐ATPase activity. The results suggest multiple modes of action of TGF‐β1 on V‐ATPase subunits in HSG cells: TGF‐β1 may regulate transcription or protein synthesis of certain subunits and trafficking of other subunits in a context‐dependent manner. Moreover, V‐ATPase is active in salivary duct cells and involved in intracellular pH regulation following acidosis.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Inflammatory Cytokines IL‐13 or IL‐17/TNFα Do Not Alter the Low Paracellular Bicarbonate Permeability of Cystic Fibrosis Airway Epithelia
Authors: Thornell Ian Michael , Rehman Tayyab , Welsh Michael J
Published: June 2021

The airway‐surface liquid, the thin aqueous layer on the apical side of airway epithelia, maintains a pH that is more acidic than the serosal pH. For human large airways, this acidic pH is the balance of HCO3− secretion by the cystic fibrosis transmembrane conductance regulator (CFTR) and H+ secretion by the H+/K+ pump ATP12A, both transcellular mechanisms. Newborn humans with cystic fibrosis (CF) have an acidic airway‐surface liquid pH compared to non‐CF newborns. With time, the pH difference between CF and non‐CF individuals disappears. However, adult CF epithelia cultured at the air‐liquid interface are more acidic than non‐CF epithelia. We hypothesized that CF‐related inflammation in vivo is responsible for the age‐dependent airway alkalinization. Here, we tested the hypothesis that cytokines increase paracellular movement of HCO3− into the airway‐surface liquid. Dilution potentials observed for cultured CF airway indicate that paracellular transport favored cations (PCl/PNa = 0.7). The paracellular conductance and selectivity were unaffected by changing the pH from 7.4 to 6.0. HCO3− was less permeable than Cl− through the paracellular pathway (PHCO3/PNa = 0.35). Treating cultures with cytokines (IL‐13 or IL‐17 and TNFa), which increase the airway‐surface liquid pH, did not affect paracellular PHCO3/PNa. These data suggest that differences in transcellular pH transport are responsible for cytokine‐mediated ASL pH changes. Similar transcellular mechanisms may cause the longitudinal ASL pH changes observed for CF patients.

Support or Funding Information

MJW is an Investigator of the Howard Hughes Medical Institute

Cystic Fibrosis Foundation Research Development Program

NIH HL091842

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
NBCe1 in the Kidney and Lower Urogenital Tract
Authors: Romero Phinea Z , Holmes Heather L , Cadena Mark T , Gibbons Simon J , Farrugia Gianrico , Vezina Chad M , Romero Michael F
Published: June 2021

NBCe1 is an electrogenic Na+ bicarbonate cotransporter expressed as three isoforms. NBCe1A is mainly found in the kidney (100% activity), NBCe1B is a general isoform (~25% activity), and NBCe1C is found in the nervous system (20% activity). This project was to characterize mice with loss of NBCe1 in the kidney and urogenital tract and to test isoform activity ± IRBIT. Previous work has shown that NBCe1‐B is activated when IRBIT is present and interacts with the N‐terminus (Nt). Even though NBCe1C shares this Nt, the effects of IRBIT on human NBCe1C are unknown. Interstitial Cells of Cajal (ICC)pacemaker cells in the gastrointestinal tract (c‐kit+) have NBCe1C, IRBIT and require bicarbonate for normal gut activity. Developmentally similar ICC cells are found in the urogenital tract; however, NBCe1C locations within the kidney and urogenital tract are unknown. Using c‐kit‐copGFP and NBCe1A‐knockout mice, kidneys, ureters, prostate, bladder, and urethra were dissected and analyzed via direct imaging, sectioning, and immunofluorescence. Oocytes injected with NBCe1C ± IRBIT were voltage clamped to determine the cotransporter's activity. “Strings” of c‐kit+‐cells were found in the copGFP & nbce1A kidneys. In nbce1(+/−)‐(Het) mice (Figure), prostate ducts appeared enlarged, and in nbce1A−/− kidney, c‐kit protein was broadly expressed, showing cluster colocalization with NBCe1C. NBCe1C is not obviously expressed in WT or copGFP mice. Electrophysiology data showed that IRBIT activates NBCe1C by ~10‐fold. As c‐kit is also a marker of stem cells, NBCe1C/c‐kit association and c‐kit increase in nbce1A−/− mice, could suggest that NBCe1A loss elicits kidney repair itself (proliferation) and causes expression of other NBCe1‐isoforms.

Support or Funding Information

R25‐DK101405, R01‐DK057061, U54‐DK100227 (Mayo) and U54‐DK104310 (UW‐Madison)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effects of Adrenosterone, Testosterone, and 17β‐Estradiol on the Gene Expression of Insulin‐Like Growth‐Factor Binding Proteins (igfbps) in Atlantic Salmon Smolts
Authors: White Rebecca , Cairnduff Ross , Nilsen Tom , Einarsdottir Ingibjorg , Bjornsson Thrandur , McCormick Stephen , Breves Jason
Published: June 2021

The growth hormone (Gh)/insulin‐like growth‐factor (Igf) system is a key regulator of growth in teleost fishes, including salmonids. Igfs interact with a suite of binding proteins, termed Igf binding proteins (Igfbps), which modify their biological activities. Atlantic salmon (Salmo salar) express an expanded array of igfbp gene transcripts in liver, the primary site of Igfbp production. While gonadal steroids are known to impact the growth of fishes, there is little information on how androgens and estrogens affect the expression of various igfbps. In the current study, we characterized how 14‐day implants of adrenosterone (OA), testosterone (T) or 17β‐estradiol (E2) affected the Gh/Igf/Igfbp network in Atlantic salmon smolts. OA did not affect any of the parameters studied. There were no effects of T or E2 on body mass, plasma levels of Igf1, or hepatic igf1, igf2 or gh receptor mRNA levels. E2 stimulated hepatic estrogen receptor α mRNA levels by 17‐fold, while E2 and T stimulated hepatic vitellogenin mRNA levels by 140‐ and 19‐fold, respectively. Hepatic igfbp1b1 and igfbp4 mRNA levels were diminished by E2 but not T, whereas igfbp2a was diminished by T, but not E2. Alternatively, both T and E2 stimulated igfbp5a. igfbp2b2, igfbp5b2 and igfbp6b were not impacted by any of the tested steroids. Our findings suggest that steroid‐specific effects on the gene expression of various igfbps provide a means for gonadal steroids to modulate the Gh/Igf system.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Influence of Codeine on Swallow in the Anesthetized Cat: Evidence for Peripheral and Central Actions of Opioids to Induce Dysregulation of Deglutition
Authors: Bolser Donald C , Shen Tabitha Y , Musselwhite M Nicholas , Rose Melanie J , Davenport Paul W , Morris Kendall M , Pitts Teresa
Published: June 2021

Systemic administration of opioids has been associated with aspiration and swallow dysfunction in humans. The extent to which these outcomes are due to solely central, or both central and peripheral actions, of these drugs is unknown. Codeine is a commonly prescribed opioid that has both central and peripheral actions to affect the cough reflex in animal models. We speculated that systemic administration of codeine would induce dysfunctional swallowing and that this effect would have a peripheral component. Experiments were conducted in spontaneously breathing, anesthetized cats (n=19). The animals were tracheotomized and EMG electrodes were placed in upper airway and chest wall respiratory muscles for recording swallow related motor activity. The animals were allocated into three groups: vagal intact (VI), cervical vagotomy (CVx), and supra‐nodose ganglion vagotomy (SNVx). A dose‐response to intravenous codeine (0.1–10 mg/kg) was performed in each animal. Swallowing was elicited by injection of 3 ml of water into the oropharynx. Results demonstrated a significant dose‐related increase in spontaneous swallowing (per 7 minute period between doses) in each group (VI: vehicle 0.2±0.2 to 10 mg/kg codeine 6.6±4.0, SNVx: vehicle 0.2±0.2 to 10 mg/kg codeine 4.0±2.3, CVx: vehicle 2.3±1.3 to 13±6.0 10 mg/kg codeine). Additionally, the number of induced swallows after vehicle was significantly higher in the VI group than in SNVx (p<0.04), and in the CVx compared to the SNVx group at 10mg/kg (p<0.05). Codeine also demonstrated dose‐dependent effects on upper airway motor drive during the induced swallow trials. The thyropharyngeus muscle EMG activation was significantly increased in the VI and CVx groups by 2–4 fold in a dose‐related manner (p<0.01). Also, in the CVx group, the geniohyoid muscle EMG activation was significantly increased (p<0.05). Under control conditions the presence of spontaneous swallows is rare, and their presence in response to codeine supports a strong central action and likely a dysregulation of the inhibitory influences on the swallow pattern generator. Unlike cervical vagotomy, section of the vagus nerve rostral to the nodose ganglion eliminates superior laryngeal nerve afferents. At the highest dose of codeine, the reduced spontaneous swallow number in the SNVx group relative to CVx is consistent with a peripheral excitatory action of codeine either on pharyngeal/laryngeal receptors or in the nodose ganglion itself.

Support or Funding Information

Supported by OT2OD023854‐01, HL109025, HL131716.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Vagal and spinal pulmonary afferents contribute to respiratory variability and gender‐specific response to mechanical challenge
Authors: Huff Alyssa D , Reed Mitchell D , Mian Seema , Iceman Kimberly , Pitts Teresa
Published: June 2021

Respiratory variability is important in order to respond to internal and external perturbations. While vagal afferents have been shown to be important for feedback during breathing, the influence of spinal afferents has not been as well described. We hypothesized that disruption of vagal and spinal afferents reduces respiratory variability during eupnea and alters respiratory response during thoracic mechanical restriction (banding). We measured costal diaphragm and thyroarytenoid electromyography (EMG) activity in sodium pentobarbital anesthetized spontaneously breathing male and female Sprague Dawley rats. We conducted three sets of experiments to elucidate contributions of vagal, and spinal afferents: A) inhalation of 10% nebulized lidocaine to attenuate pulmonary vagal afferents B) bilateral injections of 10% lidocaine into the pleural space to attenuate thoracic afferent feedback; C) bilateral tracheal vagotomy caudal to the larynx. Solutions of 10% lidocaine were mixed with saline and 2% Evans Blue dye to confirm the distribution of lidocaine following nebulization and injection. Additionally, banding was performed before and after each experimental protocol. Banding significantly increased costal diaphragm amplitude which was further increased with each intervention, however there was a gender specific increase in thyroarytenoid activity with only ~50% of males demonstrating this phenomenon. Both lidocaine protocols demonstrated features of vagotomy including reduction of each eupneic phase duration coefficient of variance as well as alterations in EMG amplitude. These results demonstrate gender‐specific effects of the respiratory system to challenges, and provide preliminary evidence of the importance of non‐vagal pulmonary feedback. Moreover, this present study could have broad clinical implications in disorders such as spinal cord injury.

Support or Funding Information

This work was supported by NIH grants HL 111215, HL 103415 and OT20D001983, the Craig F. Neilson Foundation Pilot Research Grant 546714, Kentucky Spinal Cord and Head Injury Research Trust, and the Commonwealth of Kentucky Challenge for Excellence.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cough Hypersensitivity Induced by Eosinophil Granule‐Derived Major Basic Protein in Awake Mice
Authors: Athukorala Ashami , Lin An‐Hsuan , Lin Ruei‐Lung , Khosravi Mehdi , Gleich Gerald , Lee Lu‐Yuan
Published: June 2021

Non‐asthmatic eosinophilic bronchitis is one of the major causes of chronic cough. Major basic protein (MBP), an eosinophil granule‐derived cationic protein, is known to induce airway mucosal inflammation and hypersensitivity of airway sensory nerves. However, little is known about the effects of MBP on cough sensitivity. This study was carried out to determine the effect of MBP on modulating cough responses to inhalation of sulfur dioxide (SO2) and ammonia (NH3), air pollutants and chemical irritants, in a murine model. Awake mice were each placed in a recording chamber that was ventilated with a constant flow (300 ml/min) of air or irritant gas mixture. Coughs were detected by analyzing the pressure changes inside the chamber and in the intrapleural space (via telemetry), in conjunction with the audio and video signals recorded simultaneously. Cough responses to SO2 and NH3 inhalation (300 and 600 ppm, 0.1% and 0.2% balanced in air) were determined for 3 days before and ~10 days after 0.02 mg of MBP instillation into the trachea of the mouse. Our preliminary data obtained in 8 mice (the group of SO2 inhalation) and 6 mice the group of NH3 inhalation) showed: 1) inhalation of SO2 elicited cough responses in a dose‐dependent manner; 2) after the administration of MBP, cough responses to both concentrations of SO2 were significantly elevated; 3) the cough hyperresponsiveness to SO2 reached the peak ~2 days after the MBP treatment, and returned to baseline after ~7 days; 4) inhalation of NH3 also elicited cough responses in a dose‐dependent manner, which was augmented after the MBP treatment in a pattern similar to that of SO2. In conclusion, these findings suggest a possible role of MBP in the chronic cough associated with eosinophilic bronchitis.

Support or Funding Information

NIH grants UL1TR001998 and AI123832

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Perception of Intensity and Unpleasantness for 1‐Breath, 10‐Breath and 10‐Minute Inspiratory Resistive Loaded Breathing in Healthy Adults
Authors: Davenport Matthew P. , Davenport Paul Wesley , Feinstein Justin , Khalsa Sahib , von Leupoldt Andreas
Published: June 2021

Respiratory load is key in various respiratory diseases, accompanied by ventilatory compensation, cognitive awareness and affective perception. Loaded breathing can occur for a few breaths, minutes or days. Inspiratory loads elicit breathing sensations associated with behavioral modulation of breathing elicit breathing patterns to maintain alveolar ventilation, minimize work of breathing and minimize aversive load sensations. Increased inspiratory load is associated with cognitively sensing load magnitude and aversive perception of loaded breathing. The aim of this study was to determine the relationship between intensity and unpleasantness perception of 1‐breath, 10‐breath and 10‐minute breathing against extrinsic inspiratory loads. We hypothesized longer inspiration time against an extrinsic load will illicit greater intensity and unpleasant perceptions of the load. Additionally greater magnitude loads will increase perceived intensity and unpleasantness with longer breathing times. Healthy participants were tested while breathing through a non‐rebreathing circuit with inspiratory flow‐resistive loads. For one trial, the subjects inspired for 10 consecutive breaths for each of 5 load magnitudes (R=0, 5, 10, 25, 50, 100 cmH2O/L/s). Subjects estimated their perceived load intensity (MEInt) and unpleasantness (MEUn) for breaths 1 and 10. In a separate trial, the individuals respired with no‐load for 1 minute, then the R=50 cmH2O/l/s load for 10 minutes, followed by 1 minute of no‐load breathing. Subjects estimated their perceived load MEInt and MEUn every minute. In the 10‐breath loading trials, the MEInt increased with increasing load magnitude. There was an increase in MEInt from breath 1 to 10 for R=50 and R=100 cmH2O/L/s. MEUn increased with load magnitude however MEUn breath 1 v. 10 was not significant. The MEInt and MEUn increased from 60 to 600 sec in the 10‐minute trial. These results suggest load magnitude and loaded breathing duration are critical factors in the perception of intensity and unpleasantness.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.