bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melatonin plus treadmill exercise synergistically promotes neurogenesis and reduce apoptosis in focal cerebral ischemic rats (877.17)
Authors: Lee Minkyung , Lee Seunghoon , Hong Yonggeun 
Published: June 2021

Ischemic stroke results from sudden decrease or loss of blood flow to the brain, resulting in damage to neurological function and neuronal networks, cognition. The purpose of this study, we determined whether melatonin and/or treadmill exercise could induce neurogenesis, thereby promoting functional recovery in ischemic brain. Following the MCAo, Sprague‐Dawley (SD) rats were randomly divided into control (Con), MCAo, MCAo+Exercise (MCAo+Ex), MCAo+Melatonin (MCAo+MT), Melatonin combined Exercise in MCAo (MCAo+MT+Ex). The 8 week old SD rats were treated twice daily with melatonin (10 mg/kg) at 17:00 and 19:00, and trained twice daily with treadmill exercise (20 m/min, 6 days/week) at 17:00 and 22:00. At the Golgi‐cox staining, dendrite density in the MCAo+MT+Ex group was higher than in MCAo group. We confirmed that MCAo+MT+ME group was significantly recovered the neurological symptom in behavioral assessment (p<.01). Moreover, MCAo+MT and MCAo+MT+Ex were significantly increased both DCx and GFAP mRNA expression. In conclusion, we suggest that melatonin with and without treadmill exercise intervention enhanced neurogenesis and neuronal cell reconstruction in damaged brain lesions, thereby induced improvement of neurological dysfunction in animal model.Key words: Melatonin, Treadmill exercise, Neurogenesis, Apoptosis, Focal cerebral ischemia
Neuron‐targeted Cav‐1 as a novel therapy for motor cortex and hippocampal traumatic brain injury (877.3)
Authors: Posadas Edmund , Cui Weihua , Schilling Jan , Kassan Adam , Niesman Ingrid , Patel Piyush , Head Brian 
Published: June 2021

Traumatic Brain Injury (TBI) is the leading cause of death in young adults in the Western world. Membrane/lipid rafts (MLR) are plasmalemmal microdomains enriched in sphingolipids, cholesterol, and the protein caveolin (Cav). We have previously shown that primary neurons in vitro transfected with neuron‐targeted Cav‐1 (SynCav1) significantly enhanced expression of pro‐survival and pro‐growth signaling components and increased dendritic growth and arborization. We therefore extended our studies to an in vivo mouse traumatic brain injury (TBI) model utilizing a controlled cortical impact (CCI; 5 m/sec; +1.5 to ‐2.5 bregma, right hemisphere). CCI was performed on a transgenic mouse that overexpresses Cav‐1 only in neurons (SynCav1TG). We performed motor and cognitive tests on sham (craniotomy only) and CCI TG positive (TGpos) and negatives (TGneg). Motor tests were performed on a weekly basis post CCI. Fear conditioning was performed 35 days post CCI. Preliminary data shows a deficit in the inverted wire grid and hippocampal dependent fear conditioning in CCI TGneg mice. We are currently testing the TGpos mice in our CCI model as well as AAV‐SynCav1 intravenous injections in WT mice 24 hr post CCI. Such data could indicate that neuron‐targeted Cav‐1 may be a novel therapy to limit brain injury after TBI and may be an effective therapeutic intervention for other neurodegenerative diseases.Grant Funding Source: Supported by VA Merit (B.P. Head) and NINDS (B.P. Head)
Gender differences in vascular responses to carotid baroreflex stimulation (879.14)
Authors: Lloyd Matthew , Der Andrew , Claydon Victoria 
Published: June 2021

The relationships between sympathetic nerve activity, arterial blood pressure and cardiac output are strikingly different in young men and women, and further modified by aging. We hypothesised that some of these differences may be mediated by altered baroreflex control of arterial pressure. Full baroreflex response curves are seldom constructed, particularly for vascular resistance responses, and possible gender differences in these responses are unclear.We, therefore, used a variable‐pressure neck collar system to deliver a range of positive and negative pressures to the carotid sinus in young men (n=5) and women (n=5). Beat‐to‐beat mean arterial pressure (MAP), R‐R interval, and brachial blood flow velocity (BBFV) were recorded noninvasively. From these data we constructed full cardiac and forearm vascular resistance (FVR=MAP/BBFV) baroreflex response curves. Gain, set point, threshold and saturation were calculated.Resting heart rates and blood pressures were similar in men and women. Cardiac and FVR baroreflex gains, threshold and saturation were also similar in men and women. The set point for the cardiac responses in women (105±10 mmHg) was greater than in men (77±7 mmHg, p<0.05); the set point for FVR responses was similar. In both groups the latency of the maximal MAP response to negative pressure (13 beats) was larger than positive pressure (7 beats, p<0.05). Overall there was a significant correlation between the set point of the blood pressure response and neck circumference (r= ‐0.64, p<0.05).These data suggest there may be subtle but physiologically relevant differences in carotid baroreflex control in young men and women. Given the impact of gender and age on susceptibility to hypertension, further study is required to evaluate these responses in older men and women.Grant Funding Source: None
Effects of life history on oxygen delivery in the grasshopper jumping leg (879.22)
Authors: Zembrzuski Deanna , Kirkton Scott 
Published: June 2021

Although the insect tracheal system is extremely efficient, oxygen delivery is reduced during the intermolt period. Intermolt growth results in compressed tracheae, reduced tracheal volume, and reduced femoral air sac ventilation rates. Gravidity reduces tracheal volume in adult female grasshoppers; however, it is unknown whether gravid grasshoppers also have lower ventilation rates. Using micro‐dissections and video analysis, we examined the tracheal system of the abdomen and femur of ten (5 females; 5 males) American locust grasshoppers (Schistocerca americana). We found that abdominal compression rates correlated with the inflation of proximal and distal femoral air sacs. Females (1.99 to 2.95 g) had higher compression rates in both their abdomens (36.2 ± 3.62 min‐1; mean ± s.e.m.) and femoral air sacs (36.8 ± 3.73 min‐1) than male grasshoppers (1.07 to 1.27 g; abdomen 28.6 ± 2.04 min‐1 and femoral air sacs 26.8 ± 1.85 min‐1). The most gravid females showed the highest abdominal and femoral air sac compression rates. These findings suggest that gravid females will compensate for reduced tracheal volumes by increasing tracheal ventilation rates. Current research is examining how gravidity affects tibial and tarsal air sac compression rates.Grant Funding Source: Supported by Union College Undergraduate Research Grants
Cardiovascular and skeletal muscle sympathetic nerve activity correlates in the embryonic chicken (Gallus domesticus) (879.6)
Authors: Onyemaechi Clinton , Crossley Dane , Hedrick Michael 
Published: June 2021

The embryonic chicken (Galls domesticus) is a classic model for quantifying changes in cardiovascular form and function. Alterations in blood pressure, heart rate and blood flow have been quantified at multiple points of the 21 day incubation period. In addition, several regulatory systems have been assessed using pharmacological manipulation of receptors. However, the integration of cardiovascular function, and the capacity for central nervous system regulation of the cardiovascular system, has not been extensively investigated for non‐mammalian vertebrates. We investigated the correlation between muscular sympathetic nervous activity (mSNA) and fluctuations in arterial pressure and heart rate of the embryonic chicken. On day 18 of incubation, embryos were surgically instrumented with bipolar silver electrodes placed around the peroneal nerve to measure mSNA. On the following day a pressure catheter was inserted into a tertiary chorioallantoic artery to monitor arterial pressure and heart rate. The embryonic cardiovascular responses to pharmacologically‐induced vasodilation and vasoconstriction were investigated with sodium nitroprusside (SNP) and phenylephrine (Phe), respectively. In recovered embryos, acute spontaneous reductions in arterial pressure were associated with an increase in mSNA activity. In contrast, not all changes in arterial pressure induced by SNP or Phe were inversely related to mSNA. The lack of a consistent correlation between mSNA and arterial pressure suggests that the sympathetic regulatory capacity in embryonic day 19 chickens is relatively undeveloped compared with the adult animal.Grant Funding Source: Supported by NSF CAREER award to DAC.
Anti‐aging gene klotho deficiency causes arterial stiffness via activation of aldosterone receptors and increased autophagy (880.6)
Authors: Chen Kai , Zhou Xiaoli , Sun Zhongjie 
Published: June 2021

Background & Objective. The prevalence of arterial stiffness increases with age while the klotho level decreases with age. Klotho deficiency increases circulating aldosterone levels. The objective of this study was to test the hypothesis that klotho deficiency causes arterial stiffness via activation of aldosterone receptors.Methods & Results. Klotho heterozygous (klotho+/‐) mice (1.5 years) and their wild type (WT) littermates were treated with or without aldosterone receptor blocker eplerenone (6 mg/kg/day, IP) for 3 weeks. Pulse wave velocity (PWV), a direct measure of arterial stiffness, was significantly increased in klotho+/‐ mice, suggesting that klotho deficiency causes arterial stiffening. Eplerenone abolished klotho deficiency‐induced arterial stiffening. Arterial stiffness was associated with increased collagen and decreased elastin contents in the media of aortas. Mechanistically, klotho deficiency increased arterial MMP2, MMP9 and TGFβ expression, which were blocked by eplerenone. In addition, klotho deficiency induced arterial autophagy and increased scleraxis (a transcription factor for collagen synthesis) expression, which was reversed by eplerenone.Conclusion. Klotho deficiency causes arterial stiffening via activation of aldosterone receptors which leads to upregulation of MMP2, MMP9, TGFβ, and scleraxis and increased autophagy.Grant Funding Source: Supported by HL105302 and HL 102074.
MMP‐9 deletion improves vascular permeability and angiogenesis in aging mice (880.8)
Authors: Yabluchanskiy Andriy , Ma Yonggang , Chiao Ying Ann , Voorhees Andrew , Han Hai‐Chao , Jin Yufang , Lindsey Merry 
Published: June 2021

Aging is a major risk factor for cardiac morbidity and mortality. Increasing age associates with increased MMP‐9 expression, increased ECM degradation, and a decline in cardiac function. Previously, we demonstrated that wild type (WT) mice >18 months of age show impaired diastolic function, which was attenuated by MMP‐9 deletion. To investigate the changes that occur before cardiac dysfunction develops, we examined 6‐9 and 15‐18 month old (mo) WT and MMP‐9 null (Null) mice. All groups showed similar cardiac function by echocardiography and Doppler, indicating that functional changes in the left ventricle (LV) had not yet developed. Plasma proteomic profiling and LV tissue analysis revealed age‐associated increases of von Willibrand factor and VEGF in WT mice, which were enhanced in Null mice, suggesting that aging and MMP‐9 deletion stimulates angiogenesis. However, the number of vessels evidenced by GSL‐1 staining and protein expression was increased only in the 15‐18 mo Null LV. To evaluate vascular function, we injected WT and Null mice with FITC labeled dextran (70 kDa). The 15‐18 WT mo mice showed increased vascular permeability compared to the younger WT controls, which was significantly attenuated in Null mice. Our findings revealed that the age‐associated increase in MMP‐9 links with increased vascular permeability, which may contribute to the development of diastolic dysfunction.Grant Funding Source: Supported by SC2 HL101430,HL095852,HHSN 268201000036C(N01‐HV‐00244),R01HL075360,HL05197,5I01BX000505
Resistance exercise heart rate recovery in youth with Prader‐Willi syndrome, nonsyndromal obese children and lean controls (881.13)
Authors: Castner Diobel , Pham Hoang , Judelson Daniel , Rubin Daniela 
Published: June 2021

Prader‐Willi Syndrome (PWS) is a genetic disorder characterized by excess adiposity, low lean mass and hypotonia. Heart rate recovery (HRR), a determinant of all‐cause mortality, is slower in PWS in response to endurance exercise. This study examined how adiposity and PWS influence resistance exercise HRR. Eight PWS youth (age=11.5±3.5 y, body fat=44.1±3.9 %) and 16 nonsyndromal obese (OB: age=9.5±1.2 y, body fat=39.5±4.5 %) and 12 lean (LN: age=9.1±1.2 y, body fat=17.8±5.1 %) children completed six sets of a bench‐stepping protocol. Each set consisted of 10 steps per leg onto an adjustable platform (~20% of stature) while donning a weighted vest (~50% of lean body mass), followed by one minute of rest. HRR value (HRRV) was calculated as the difference between test termination HR and HR one minute after exercise. One‐way ANOVA showed PWS had a significantly lower HRRV (44±13 beats) compared to OB (63±20 beats; p=0.035) and LN (63±13 beats; p=0.044). Similar to previous research in submaximal endurance exercise, nonsyndromal OB and LN children recovered faster than PWS, suggesting adiposity alone did not affect resistance exercise HRR. The lower HRRV in PWS may be attributed to poor cardiovascular fitness and/or autonomic nervous system dysfunction inherent to the syndrome. Further, resistance exercise HRRVs appeared comparable to previously studied endurance exercise HRRVs in youth.Grant Funding Source: Supported by USAMRAA Award W81XWH‐08‐1‐0025
Influence of fitness on core temperature thresholds for exercise ventilation (882.6)
Authors: Yogev Assaf , Martin Des , Walsh Michael , White Matthew 
Published: June 2021

During incremental exercise from rest to exhaustion, core temperature thresholds are evident at exercise intensities greater than that at the anaerobic threshold or the onset of blood lactate accumulation. The effect of aerobic fitness on these core temperature thresholds remains poorly understood. PURPOSE: To compare oesophageal temperature (TES) thresholds for exercise ventilation (VE) between competitive, trained and untrained males during incremental exercise. HYPOTHESIS: Trained athletes will demonstrate a greater TES threshold for VE than untrained males. Methods: Seven college‐aged competitive male cyclists with a VO2MAX of 63.9 ± 3.7 mL•min‐1•kg‐1 (mean ± SD) and 7 college‐aged untrained males with a VO2MAX of 53.9 ± 3.5 mL•min‐1•kg‐1 volunteered for the study that approved by the SFU Office of Research Ethics. VE and its components were measured with a breath‐by‐breath metabolic cart and volunteers pedaled an electrically braked cycle ergometer at an ambient temperature of ~22oC. Each incremental exercise test started with a load of 60 W on the cycle ergometer that was incremented by 35 W/min until exhaustion. Core temperature thresholds from plots of ventilatory equivalents for oxygen (VE/VO2) and carbon dioxide (VE/VCO2) as a function of TES were 1.3°C greater (P<0.01) in the trained vs. the untrained group. The trained group relative to the untrained cyclists had a higher (P<0.01) anaerobic threshold as determined from plots of VE/VO2 and VE/VO2 as a function of VO2. CONCLUSION: Evidence supports the hypothesis that increased aerobic fitness results in a higher core temperature threshold for VE during incremental exercise.Grant Funding Source: Supported by NSERC and CFI
Influence of five days of reduced daily physical activity on cardiac baroreflex sensitivity during acute hyperglycemia (884.10)
Authors: Holwerda Seth , Boyle Leryn , Credeur Daniel , Thyfault John , Fadel Paul 
Published: June 2021

A sedentary lifestyle is associated with high fasting plasma glucose (i.e., insulin resistance) and decreased spontaneous cardiac baroreflex sensitivity (BRS). However, it is unknown whether a short term reduction in daily physical activity (RA) influences BRS at rest or during acute hyperglycemia. Nine recreationally active men (25 ± 2 yrs) underwent 5 days of RA by refraining from planned exercise and reducing daily steps (<5,000 steps/day). At baseline and after 5 days of RA, heart rate (ECG) and beat‐to‐beat blood pressure (BP, Finometer) were measured at rest and at 60‐ and 120‐min following an oral glucose tolerance test (OGTT). Linear regression slopes of three or more consecutive beats where systolic BP and RR interval changed in the same direction were averaged to determine overall BRS and separately for up and down sequences. Five days of RA (baseline, 12497 ± 836 vs. average RA days 1‐5, 3555 ± 280 steps, P<0.05) did not significantly influence overall BRS at rest or during the OGTT (P>0.05). However, during the OGTT, a significant reduction in BRS for up sequences (baseline, 31.6 ± 3.8 vs. 60min, 27.5 ± 3.3 vs. 120min, 22.1 ± 3.1 msec/mmHg, P<0.01) was found, whereas down sequences were unaffected (P>0.05). These preliminary findings suggest that 5 days of RA does not affect BRS at rest or during acute hyperglycemia. However, BRS to rises in BP are attenuated by acute hyperglycemia independent of short term RA.Grant Funding Source: Supported by HL‐093167 (PJF) and 5T32AR048523‐09 (SWH).
Distinguishing differences between intrinsic aerobic capacity and age: a 1H‐NMR metabolomics approach (884.19)
Authors: Shearer Jane , Falegan Oluyemi , Hepple Russell , Hittel Dustin , Koch Lauren , Britton Steven , Vogel Hans 
Published: June 2021

Differences in intrinsic aerobic capacity play a critical role in the development of perturbed metabolism, chronic disease and all‐cause mortality. Aims were to employ metabolomics to examine differences in age vs. aerobic capacity in young and old rats selectively bred for low (LCR) or high (HCR) aerobic capacity. Proton nuclear magnetic resonance spectroscopy (1H‐NMR) evaluated the metabolic profile of plasma samples obtained from fasted LCR and HCR. Multivariate statistical analysis was employed, with individual features judged based on variability R2 and predictive ability Q2 in unsupervised and supervised models built using the most significant metabolites. Taurine, pyruvate, acetone, valine, amongst others were key metabolites that contributed to distinct separation based on age (R2=0.83, Q2=0.65). In contrast, weaker predictive models were observed for LCR vs. HCR with scores of R2=0.53 and Q2=0.35 respectively. Key metabolites that decreased in HCR compared to LCR included isopropanol, o‐acetylcarnithine, sarcosine and proline. Pathway analysis highlighted changes in methionine, purine and TCA cycle intermediates. In conclusion, metabolomics analysis was a better predictor and age rather than aerobic capacity in LCR and HCR rats. This observation highlights the importance of age when attempting to isolate metabolic changes in aerobic capacity and their relation to chronic disease risk.Grant Funding Source: Supported by the Alberta Cancer Foundation
Differential effects of endurance training and resistance training on doxorubicin‐induced skeletal muscle dysfunction (884.5)
Authors: Hydock David , Bredahl Eric , Gibson Noah , Quinn Colin , Hayward Reid 
Published: June 2021

This study examined the protective effects of prior endurance training or resistance training on acute doxorubicin (DOX)‐induced skeletal muscle dysfunction. Male Sprague‐Dawley rats were endurance trained (motorized treadmill), resistance trained (raised food/water), or sedentary (normal cage activity) for 10 weeks, and following the activity treatments, animals received DOX. Skeletal muscle function was assessed ex vivo analyzing the soleus and extensor digitorum longus (EDL) to represent type I and type II muscle, respectively. DOX treatment resulted in decreased maximal twitch force in both the soleus and EDL. Endurance training provided the greatest degree of protection in the soleus whereas resistance training provided the greatest degree of protection in the EDL. The results suggest that exercise‐induced protection against DOX myotoxicity may be dependent on exercise mode and fiber type.Grant Funding Source: David S. Hydock, PhD was supported by MRSG‐12‐179‐01‐PCSM from the American Cancer Society
Exercise‐induced mobilization of endothelial progenitor cells in patients with early metabolic syndrome: relation with endothelial dysfunction and MMP‐9 (884.7)
Authors: Rocha Natalia , Sales Allan , Penedo Leticia , Pereira Felipe , Silva Mayra , Miranda Renan , Silva Jemima , Silva Bruno , Santos Aline , Nobrega Antonio 
Published: June 2021

Exercise mobilizes endothelial progenitor cells (EPCs) to peripheral blood, and this process can be regulated by matrix metalloproteinase 9 (MMP‐9). However, it is unknown if these mechanisms work properly in subjects with early metabolic syndrome (MetS). This study aimed to determine the effects of exercise on adhesion molecules, EPCs and MMP‐9 in subjects with early MetS. Fifteen subjects with early MetS (37±2yr) and nine healthy subjects (33±3yr) underwent an exercise session and a non‐exercise session, in random order. Adhesion molecules, EPCs and MMP‐9 were evaluated before and 10 minutes after the sessions. Presence of endothelial dysfunction was confirmed by brachial artery flow‐mediated dilation (FMD). At baseline, shear rate‐adjusted FMD was lower (P=0.04) and levels of sE‐selectin, sICAM‐1 and MMP‐9 were higher in subjects with MetS (P蠄0.03). No differences were found in number of EPCs between groups. After exercise, levels of sE‐selectin, sICAM‐1 and MMP‐9 were still higher in subjects with MetS (P<0.05). Subjects with MetS presented less CD34+/VEGFR2+ (P=0.02) and CD34+/CD133+/VEGFR2+ cells (P=0.02) and higher MMP‐9 activity (P<0.05) than healthy subjects. There were no differences between moments in non‐exercise session. Thus, subjects with early MetS presented impaired endothelial function at rest and altered response of EPCs to exercise that may be related to increased MMP‐9 activity.Grant Funding Source: Supported by CNPq, CAPES, FAPERJ, FINEP
Effects of maternal exercise during pregnancy on coronary artery vascular function in high fat fed swine offspring (886.2)
Authors: Blaize Nicole , Zartman Erica , Cabot Ryan , Newcomer Sean 
Published: June 2021

The purpose of this study was to test the hypothesis that maternal exercise during pregnancy would enhance coronary artery endothelial function in swine offspring that were fed a high fat diet. Pubertal gilts were divided into exercise (n =8) and sedentary (n =8) groups. Pregnant gilts in the exercise group performed treadmill exercise 5 days per week. Offspring were fed a high fat diet and endothelial (bradykinin; BK) and vascular smooth muscle (sodium nitroprusside; SNP) function were measured at 4 and 8 months of age in the left anterior descending (LAD) artery using in vitro wire myography. Exercise sows had a significantly lower resting heart rate at week 15 of pregnancy compared to their sedentary counterparts (EX: 94.43 ± 4.0; SED: 107.13 ± 3.6 bpm). There were no significant differences in litter characteristics at birth (i.e., number of piglets alive and litter weight). There were no significant differences in vasorelaxation dose response or maximal response to BK or SNP from offspring of exercise or sedentary sows at 4 months of age (BK: EX: 94.35 ± 3.8; SED: 104.1 ± 7.7 % relaxation; SNP: EX: 101.45 ± 2.3; SED: 100.44 ± 3.4 % relaxation) or 8 months of age (BK: EX: 82.75 ± 8.5; SED: 93.92 ± 7.4 % relaxation; SNP: EX: 95.44 ± 2.7; SED: 96.51 ± 1.5 % relaxation) for the LAD artery. Therefore, maternal exercise during pregnancy does not significantly alter LAD artery function at 4 or 8 months of age in swine offspring fed a high fat diet.Grant Funding Source: Supported by the American Heart Association Grant # 12FDG8540001 (S.C.N.)