An Ouyang

Dr. An Ouyang

orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 June 2019 in Nutrition
Verified
Journal Article
Closed access
MCMarilyn S. Campbell
Marilyn S. Campbell
AOAn Ouyang
An Ouyang
KIKrishnakumar I.M.
Krishnakumar I.M.
RCRichard J. Charnigo
Richard J. Charnigo
PWPhilip M. Westgate
Philip M. Westgate
BFBrad Fleenor
Brad Fleenor

1 September 2019 in Journal of Applied Physiology
Verified
Journal Article
Closed access
PDF file
AOAn Ouyang
An Ouyang
TOT. Dylan Olver
T. Dylan Olver
CECraig A. Emter
Craig A. Emter
BFBrad Fleenor
Brad Fleenor
Heart failure (HF) is associated with increased large conduit artery stiffness and afterload resulting in stiffening of the coronary arteries. Perivascular adipose tissue (PVAT) and advanced glycation end products (AGE) both promote arterial stiffness, yet the mechanisms by which coronary PVAT promotes arterial stiffness and the efficacy of exercise to prevent coronary stiffness are unknown. We hypothesized that both chronic continuous and interval exercise training would prevent coronary PVAT-mediated AGE secretion and arterial stiffness. Yucatan miniature swine were divided into four groups: control-sedentary (CON), aortic banded sedentary-heart failure (HF), aortic banded HF-continuous exercise trained (HF+CONT), and aortic banded HF-interval exercise trained (HF+IT). The left circumflex and right coronary arteries underwent ex vivo mechanical testing, and arterial AGE, elastin, and collagen were assessed. Coronary elastin elastic modulus (EEM) and elastin protein were lower and AGE was increased with HF compared with CON, which was prevented by both HF+CONT and HF+IT. Mouse aortic segments treated with swine coronary PVAT conditioned medium had lower EEM and elastin content and greater AGE secretion and arterial AGE accumulation in HF compared with CON, which was prevented by both HF+CONT and HF+IT. Aminoguanidine (AMG), an AGE inhibitor, prevented the reduction in EEM, arterial elastin content, and AGE accumulation in mouse aortic segments treated with PVAT conditioned medium in the HF group. Our data demonstrate efficacy for chronic continuous and interval exercise to prevent coronary artery stiffness via inhibition of PVAT-derived AGE secretion in a preclinical miniswine model of pressure overload-induced HF. NEW & NOTEWORTHY Our findings show that chronic continuous and interval exercise training regimens prevent coronary artery stiffness associated with inhibition of perivascular adipose tissue-derived advanced glycation end products in a translational pressure overload-induced heart failure model potentially providing an effective therapeutic option for heart failure patients.

1 March 2023 in Journal of Applied Physiology
Verified
Journal Article
Closed access
BFBrad Fleenor
Brad Fleenor
NCNicholas A. Carlini
Nicholas A. Carlini
AOAn Ouyang
An Ouyang
BDBing Du
Bing Du
MHMatthew P. Harber
Matthew P. Harber
Aortic perivascular adipose tissue (aPVAT) promotes age-related aortic stiffening in preclinical animal models, but the relation between aPVAT density and cardiovascular function in adults is unknown. We demonstrate that aPVAT, but not abdominal visceral adipose tissue density, is positively associated with aging, aortic stiffness, and higher resting aortic blood pressure in apparently healthy adults. These findings provide novel evidence for aPVAT as a viable therapeutic target for improving cardiovascular function in humans.

8 July 2024 in Life
Verified
Journal Article
Open access
PDF file
AOAn Ouyang
An Ouyang
Can ZhangCan Zhang
Can Zhang
NANoor Adra
Noor Adra
RTRyan A Tesh
Ryan A Tesh
HSHaoqi Sun
Haoqi Sun
MWMichael Brandon Westover
Michael Brandon Westover
Backgrounds: Sleep disturbances are prevalent among elderly individuals. While polysomnography (PSG) serves as the gold standard for sleep monitoring, its extensive setup and data analysis procedures impose significant costs and time constraints, thereby restricting the long-term application within the general public. Our laboratory introduced an innovative biomarker, utilizing artificial intelligence algorithms applied to PSG data to estimate brain age (BA), a metric validated in cohorts with cognitive impairments. Nevertheless, the potential of exercise, which has been a recognized means of enhancing sleep quality in middle-aged and older adults to reduce BA, remains undetermined. Methods: We conducted an exploratory study to evaluate whether 12 weeks of moderate-intensity exercise can improve cognitive function, sleep quality, and the brain age index (BAI), a biomarker computed from overnight sleep electroencephalogram (EEG), in physically inactive middle-aged and older adults. Home wearable devices were used to monitor heart rate and overnight sleep EEG over this period. The NIH Toolbox Cognition Battery, in-lab overnight polysomnography, cardiopulmonary exercise testing, and a multiplex cytokines assay were employed to compare pre- and post-exercise brain health, exercise capacity, and plasma proteins. Results: In total, 26 participants completed the initial assessment and exercise program, and 24 completed all procedures. Data are presented as mean [lower 95% CI of mean, upper 95% CI of mean]. Participants significantly increased maximal oxygen consumption (Pre: 21.11 [18.98, 23.23], Post 22.39 [20.09, 24.68], mL/kg/min; effect size: −0.33) and decreased resting heart rate (Pre: 66.66 [63.62, 67.38], Post: 65.13 [64.25, 66.93], bpm; effect size: −0.02) and sleeping heart rate (Pre: 64.55 [61.87, 667.23], Post: 62.93 [60.78, 65.09], bpm; effect size: −0.15). Total cognitive performance (Pre: 111.1 [107.6, 114.6], Post: 115.2 [111.9, 118.5]; effect size: 0.49) was significantly improved. No significant differences were seen in BAI or measures of sleep macro- and micro-architecture. Plasma IL-4 (Pre: 0.24 [0.18, 0.3], Post: 0.33 [0.24, 0.42], pg/mL; effect size: 0.49) was elevated, while IL-8 (Pre: 5.5 [4.45, 6.55], Post: 4.3 [3.66, 5], pg/mL; effect size: −0.57) was reduced. Conclusions: Cognitive function was improved by a 12-week moderate-intensity exercise program in physically inactive middle-aged and older adults, as were aerobic fitness (VO2max) and plasma cytokine profiles. However, we found no measurable effects on sleep architecture or BAI. It remains to be seen whether a study with a larger sample size and more intensive or more prolonged exercise exposure can demonstrate a beneficial effect on sleep quality and brain age.

14 June 2022 in medRxiv
Verified
Preprint
Open access
PDF file
AOAn Ouyang
An Ouyang
CZCan Zhang
Can Zhang
NANoor Adra
Noor Adra
RTRyan A. Tesh
Ryan A. Tesh
HSHaoqi Sun
Haoqi Sun
MWMichael Brandon Westover
Michael Brandon Westover
Backgrounds: Exercise is an attractive, widely accessible intervention to promote cardiovascular health; however, evidence that exercise improves brain health is sparse. Here, we hypothesized that aerobic exercise would improve brain health of sedentary older adults, as reflected by cognition health, sleep macro- and micro-architecture, and brain age index (BAI), a biomarker of brain health derived from the overnight sleep electroencephalogram (EEG). Methods: Sedentary older adults were recruited to complete a 12-week aerobic exercise. Home wearable devices were used to monitor heart rate and overnight sleep EEG over the period. NIH Toolbox Cognition Battery, in-lab overnight polysomnography, cardiopulmonary exercise testing and multiplex cytokine assay were employed to determine pre- and post-exercise brain health, exercise capacity and plasma proteins. Results: 26 participants completed the initial assessment and exercise program, and 24 completed all procedures. Participants significantly increased maximal oxygen consumption (VO2max) and decreased resting and sleeping heart rate after the exercise regimen. Cognition performances were significantly improved following the exercise program while no significant differences were seen in BAI and sleep macro- and micro-architecture. Plasma IL-4 was elevated while IL-8 was reduced after the exercise regimen. Home sleep data revealed a 3.59% increase in the percentage of N3 sleep over a 12-week. Conclusions: We conclude that cognitive function and N3 sleep were improved by a 12-week moderate-intensity exercise program in sedentary older adults, associated with improvements in VO 2 max and plasma cytokine profiles. Our data show the value of integrating multi-modal assessments to study the effect of brain health targeted approaches. Funding: Dr. Westover received support during this work from the McCance Center for Brain Health, the Glenn Foundation for Medical Research and the American Federation for Aging Research through a Breakthroughs in Gerontology Grant; through the American Academy of Sleep Medicine through an AASM Foundation Strategic Research Award; by the Football Players Health Study (FPHS) at Harvard University; from the Department of Defense through a subcontract from Moberg ICU Solutions, Inc, and by grants from the NIH (R01NS102190, R01NS102574, R01NS107291, RF1AG064312, R01AG062989, R01AG073410), and NSF (2014431). Dr. Wrann was supported by a SPARC Award from the McCance Center for Brain Health. Dr. Tanzi and Dr. Zhang were supported by the Cure Alzheimer’s Fund. Clinical trial number: National Clinical Trial: NCT04210882 One Sentence Summary: We observed that exercise improved slow wave sleep, increased circulating neuroprotective cytokines and improved cognition health in older adults.

14 May 2020 in Journal of Applied Physiology
Verified
Journal Article
Closed access
PDF file
TMTimothy M. Mahanes
Timothy M. Mahanes
MMMargaret O. Murphy
Margaret O. Murphy
AOAn Ouyang
An Ouyang
FYFrederique B. Yiannikouris
Frederique B. Yiannikouris
BFBradley S. Fleenor
Bradley S. Fleenor
ALAnalia S. Loria
Analia S. Loria
The renin-angiotensin system (RAS) precursor angiotensinogen (AGT) has been implicated in the functional and mechanical alterations of the vascular wall in response to high-fat diet (HFD). Previously, we showed that HFD exacerbates angiotensin II-induced constriction in isolated aortic rings from male rats exposed to maternal separation (MatSep), a model of early-life stress. Thus, the aim of this study was to investigate whether MatSep increases AGT secretion promoting vascular stiffness in rats fed a HFD. Male Wistar-Kyoto MatSep offspring were separated (3 h/day, postnatal days 2–14), and undisturbed littermates were used as controls. At weaning, rats were fed for 17 wk a normal diet (ND) or a HFD, 18% or 60% kcal from fat, respectively. In plasma, there was a main effect of MatSep reducing AGT concentration (P < 0.05) but no effect due to diet. In urine, ND-fed MatSep rats displayed higher AGT concentrations that were further increased by HFD (P < 0.05 vs. control). AGT mRNA abundance and protein expression were increased in adipose tissue from HFD-fed MatSep rats compared with control rats (P < 0.05). No significant differences in liver and kidney AGT levels were found between groups. In addition, MatSep augmented vascular stiffness assessed on freshly isolated aortic rings from ND-fed rats (P < 0.05), yet HFD did not worsen vascular stiffness in either MatSep or control rats. There was no correlation between plasma AGT and vascular stiffness in ND-fed rats; however, this relationship was negative in HFD-fed MatSep rats only (P < 0.05). Therefore, this study shows that MatSep-induced increases in vascular stiffness are independent of diet or plasma AGT. NEW & NOTEWORTHY This study demonstrates that there was no correlation between circulating levels of angiotensinogen (AGT) and the development of vascular stiffness in rats exposed to early-life stress and fed a normal diet. This study also shows that early-life stress-induced hypersensitive vascular contractility to angiotensin II in rats fed a high-fat diet is independent of circulating levels of AGT and occurs without further progression of vascular stiffness. Our data show that early-life stress primes the adipose tissue to secrete AGT in a sex- and species-independent fashion.