Victoria Rontoyanni

Dr. Victoria Rontoyanni

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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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21 February 2012 in British Journal of Nutrition
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Journal Article
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VRVictoria Rontoyanni
Victoria Rontoyanni
WHWendy Hall
Wendy Hall
SPSonia Pombo-Rodrigues
Sonia Pombo-Rodrigues
AAAmber Appleton
Amber Appleton
RCRoxanna Chung
Roxanna Chung
TSThomas Andrew Sanders
Thomas Andrew Sanders
Long-chain n-3 PUFA can lower blood pressure (BP) but their acute effects on cardiac output, BP and systemic vascular resistance (SVR) in response to dynamic exercise are uncertain. We compared the effects of high-fat meals rich in EPA (20 : 5n-3), DHA (22 : 6n-3) or oleic acid (control) on cardiac output, BP and SVR in response to exercise stress testing. High-fat meals (50 g fat) containing high-oleic sunflower oil enriched with 4·7 g of either EPA or DHA v. control (high-oleic sunflower oil only) were fed to twenty-two healthy males using a randomised cross-over design. Resting measurements of cardiac output, heart rate and BP were made before and hourly over 5 h following the meal. A standardised 12 min exercise test was then conducted with further measurements made during and post-exercise. Blood samples were collected at fasting, 5 h postprandially and immediately post-exercise for the analysis of lipid, glucose and 8-isoprostane-F2α (8-iso-PGF2α). Plasma concentrations of EPA and DHA increased by 0·22 mmol/l 5 h following the EPA and DHA meals, respectively, compared with the control (P < 0·001). Resting cardiac output and 8-iso-PGF2α increased similarly following all meals and there were no significant differences in cardiac output during exercise between the meals. SVR was lower at 5 h and during exercise following the DHA but not EPA meal, compared with the control meal, by 4·9 % (95 % CI 1·3, 8·4; P < 0·01). Meals containing DHA appear to differ from EPA with regard to their effects on cardiovascular haemodynamics during exercise.

31 January 2017 in Nutrients
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Journal Article
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VRVictoria Rontoyanni
Victoria Rontoyanni
JAJaqueline Avila
Jaqueline Avila
SKSapna Kaul
Sapna Kaul
RWRebeca Wong
Rebeca Wong
SVSreenivas P Veeranki
Sreenivas P Veeranki
Background: Vitamin D is essential for maintaining bone mineralization and calcium homeostasis, and prevents falls and fractures in older adults. Mexico is undergoing an epidemiologic and demographic transition with increasing obesity rates. The study’s aim was to determine the association of obesity with serum 25-hydroxyvitamin D [25(OH)D] concentrations in older Mexican adults. Methods: Data from 1772 Mexicans, aged ≥50 years, enrolled in a sub-sample of the 3rd wave of the Mexican Health and Aging Study, were included. Serum 25(OH)D concentrations were used to define vitamin D status, and were categorized into tertiles. Body mass index measures were used to categorize older adults into under/normal weight, overweight, and obese groups. Multinomial logistic regression models were used to assess the relationship, adjusting for potential confounders. Results: Approximately 40% and 37% of older Mexican adults were either overweight or obese, respectively. Compared to under/normal weight older Mexicans, obese adults were 1.78 times (95% Confidence Interval (CI) 1.27–2.48) and 1.94 times (95% CI 1.40–2.68) more associated with the first and second tertile concentrations of serum 25(OH)D, respectively. Overweight adults were 1.52 times (95% CI 1.12–2.06) more associated with the second tertile of serum 25(OH)D concentration than under/normal weight adults. Conclusion: Overweight/Obesity was found to be significantly associated with low concentrations of serum 25(OH) in older Mexican adults.

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EBElizabeth Blears
Elizabeth Blears
JEJessica Elias
Jessica Elias
CTChristian Tapking
Christian Tapking
CPCraig Porter
Craig Porter
VRVictoria Rontoyanni
Victoria Rontoyanni
Supervised resistance training appears to be a promising alternative exercise modality to supervised walking in patients with peripheral artery disease (PAD). This meta-analysis examined the efficacy of supervised RT for improving walking capacity, and whether adaptations occur at the vascular and/or skeletal muscle level in PAD patients. We searched Medline, CINAHL, Scopus, and Cochrane Central Register of Controlled Trials databases for randomized controlled trials (RCTs) in PAD patients testing the effects of supervised RT for ≥4 wk. on walking capacity, vascular function, and muscle strength. Pooled effect estimates were calculated and evaluated using conventional meta-analytic procedures. Six RCTs compared supervised RT to standard care. Overall, supervised RT prolonged claudication onset distance during a 6-min walk test (6-MWT) (101.7 m (59.6, 143.8), p < 0.001) and improved total walking distance during graded treadmill walking (SMD: 0.67 (0.33, 1.01), p < 0.001) and the 6-MWT (49.4 m (3.1, 95.6), p = 0.04). Five RCTS compared supervised RT and supervised intermittent walking, where the differences in functional capacity between the two exercise modalities appear to depend on the intensity of the exercise program. The insufficient evidence on the effects of RT on vascular function and muscle strength permitted only limited exploration. We conclude that RT is effective in prolonging walking performance in PAD patients. Whether RT exerts its influence on functional capacity by promoting blood flow and/or enhancing skeletal muscle strength remains unclear.

1 June 2019 in Clinical Nutrition
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Journal Article
Closed access
IMIoannis Malagaris
Ioannis Malagaris
DHDavid N. Herndon
David N. Herndon
EPEfstathia Polychronopoulou
Efstathia Polychronopoulou
VRVictoria Rontoyanni
Victoria Rontoyanni
CAClark R. Andersen
Clark R. Andersen
LSLabros S. Sidossis
Labros S. Sidossis

1 November 2018 in Burns
Verified
Journal Article
Closed access
Janos Cambiaso DanielJanos Cambiaso Daniel
Janos Cambiaso Daniel
VRVictoria Rontoyanni
Victoria Rontoyanni
GFGuillermo Foncerrada
Guillermo Foncerrada
ANAnthony Nguyen
Anthony Nguyen
KCKarel Capek
Karel Capek
DHDavid N. Herndon
David N. Herndon

1 August 2018 in Shock
Verified
Journal Article
Open access
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VRVictoria Rontoyanni
Victoria Rontoyanni
IMIoannis Malagaris
Ioannis Malagaris
DHDavid N. Herndon
David N. Herndon
EREric Rivas
Eric Rivas
KCKarel Capek
Karel Capek
CPCraig Porter
Craig Porter
Background: Restoring normal mitochondrial function represents a new target for strategies aimed at mitigating the stress response to severe burn trauma and hastening recovery. Our objective was to investigate the determinants of skeletal muscle mitochondrial respiratory capacity and function and its association with glucose metabolism and functional capacity in burned children. Methods: Data from burned children enrolled in the placebo arm of an ongoing prospective clinical trial were analyzed. Mitochondrial respiratory capacity was determined in permeabilized myofibers by high-resolution respirometry on at least one occasion per participant. In subsets of patients, glucose kinetics and cardiorespiratory fitness (VO2peak) were also determined. Mixed multiple regression models were used to identify the determinants of mitochondrial respiratory function and to assess the relationship between mitochondrial respiration and both glucose control and functional capacity (VO2peak). Main results: Increasing full-thickness burn size was associated with greater adjusted coupled (ATP-producing) respiration, adjusted for age, sex, sepsis, and time of testing (P < 0.01; n = 55, obs = 97). Girls had on average 23.3% lower coupled respiration (adjusted mean and 95% confidence of interval [CI], −7.1; −12.6 to −1.7 pmol/s/mg; P < 0.025) and 29.8% lower respiratory control than boys (adjusted mean and 95% CI, −0.66; −1.07 to −0.25; P < 0.01; n = 55, obs = 97). The presence of sepsis was associated with lower respiration coupled to ATP production by an average of 25.5% compared with nonsepsis (adjusted mean and 95% CI, −6.9; −13.0 to −0.7 pmol/s/mg; P < 0.05; n = 55, obs = 97), after adjustment for age, sex, full-thickness burn size, and time of testing. During a hyperinsulinemic euglycemic clamp, hepatic glucose release was associated with greater coupled respiration and respiratory control (P < 0.05; n = 42, obs = 73), independent of age, sepsis, full-thickness burn size, and time postinjury testing. Coupled respiration was positively associated with VO2peak after adjustment for age, full-thickness burn size, and time of exercise testing (P < 0.025; n = 18, obs = 25). Conclusions: Burn severity, sex, and sepsis influence skeletal muscle mitochondrial function in burned children. Glucose control and functional capacity are associated with altered mitochondrial respiratory function in muscle of burn survivors, highlighting the relationship of altered muscle bioenergetics with the clinical sequelae accompanying severe burn trauma.