Charles Ryan Yates

Dr. Charles Ryan Yates


Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

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

Representative Publications

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22 January 2021 in Journal of Dietary Supplements
Verified
Journal Article
Closed access
CYCharles Ryan Yates
Charles Ryan Yates
EBEugene J. Bruno
Eugene J. Bruno
MYMary E. D. Yates
Mary E. D. Yates
Emergent health threats have heightened human awareness of the need for health and wellness measures that promote resilience to disease. In addition to proper nutrition and exercise, health-conscious consumers are seeking natural-based modalities, e.g. botanical preparations, that positively impact the immune system. In Ayurvedic ethnomedicine, Tinospora cordifolia (T. cordifolia), a deciduous climbing shrub indigenous to India, has been used to historically to combat acute and chronic inflammation as well as to promote a balanced immune response. As a dietary supplement, T. cordifolia has been administered most often as a decoction either alone or in compositions containing other medicinal plant extracts of the Terminalia and Phyllanthus species. Extensive phytochemical characterization of aqueous and alcoholic extracts of different Tinospora species has identified over two hundred different phytochemicals from non-overlapping chemical classes with the most abundant being diterpenoids containing the clerodane-type skeleton. Numerous pharmacology studies have demonstrated that T. cordifolia modulates key signaling pathways related to cell proliferation, inflammation, and immunomodulation. However, rigorous dereplication studies to identify active constituents in various T. cordifolia extracts and their fractions are lacking. In this review, we will summarize the current information regarding T. cordifolia’s ethnomedicinal uses, phytochemistry, pharmacological activities, and safety in order to highlight its potential as an immunomodulatory dietary supplement.

1 October 2020 in Journal of Chromatography B
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Journal Article
Closed access
YWYan-Hong Wang
Yan-Hong Wang
GMGoutam Mondal
Goutam Mondal
MBMatthew Butawan
Matthew Butawan
RBRichard J. Bloomer
Richard J. Bloomer
CYCharles Ryan Yates
Charles Ryan Yates

1 January 2017 in Molecular Pharmacology
Verified
Journal Article
Open access
PDF file
JTJordan J. Toutounchian
Jordan J. Toutounchian
JPJayaprakash Pagadala
Jayaprakash Pagadala
DMDuane D. Miller
Duane D. Miller
JBJerome Baudry
Jerome Baudry
FPFrank Park
Frank Park
CYCharles Ryan Yates
Charles Ryan Yates
Targeting vascular endothelial growth factor (VEGF) is a common treatment strategy for neovascular eye disease, a major cause of vision loss in diabetic retinopathy and age-related macular degeneration. However, the decline in clinical efficacy over time in many patients suggests that monotherapy of anti-VEGF protein therapeutics may benefit from adjunctive treatments. Our previous work has shown that through decreased activation of the cytoskeletal protein paxillin, growth factor–induced ischemic retinopathy in the murine oxygen-induced retinopathy model could be inhibited. In this study, we demonstrated that VEGF-dependent activation of the Src/FAK/paxillin signalsome is required for human retinal endothelial cell migration and proliferation. Specifically, the disruption of focal adhesion kinase (FAK) and paxillin interactions using the small molecule JP-153 inhibited Src-dependent phosphorylation of paxillin (Y118) and downstream activation of Akt (S473), resulting in reduced migration and proliferation of retinal endothelial cells stimulated with VEGF. However, this effect did not prevent the initial activation of either Src or FAK. Furthermore, topical application of a JP-153-loaded microemulsion affected the hallmark features of pathologic retinal angiogenesis, reducing neovascular tuft formation and increased avascular area, in a dose-dependent manner. In conclusion, our results suggest that using small molecules to modulate the focal adhesion protein paxillin is an effective strategy for treating pathologic retinal neovascularization. To our knowledge, this is the first paradigm validating modulation of paxillin to inhibit angiogenesis. As such, we have identified and developed a novel class of small molecules aimed at targeting focal adhesion protein interactions that are essential for pathologic neovascularization in the eye.

1 September 2017 in Journal of Caffeine Research
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Journal Article
Closed access
HHHui He
Hui He
DMDejian Ma
Dejian Ma
LCLaura Brooks Crone
Laura Brooks Crone
MBMatthew Butawan
Matthew Butawan
BMBernd Meibohm
Bernd Meibohm
CYCharles Ryan Yates
Charles Ryan Yates
Objective: Theacrine, a methylurate class purine alkaloid, triggers diverse pharmacologic responses, including psychostimulatory activity by modulation of adenosinergic and dopaminergic pathways. In a double-blind, placebo-controlled study, theacrine increased energy, concentration, and mood, while reducing fatigue. Because caffeine, a methylxanthine purine alkaloid, is frequently coadministered with theacrine, we sought to determine if a pharmacokinetic and/or pharmacodynamic interaction existed between theacrine and caffeine. Methods: Eight healthy adults received theacrine, as TeaCrine® (25 or 125 mg), caffeine (150 mg), or a combination of theacrine (125 mg) and caffeine (150 mg) in a randomized, double-blind crossover study. Blood samples were collected over a 24-hour period and analyzed by Liquid chromatrography-mass spectrometry/mass spectrometry (LC-MS/MS) for theacrine, caffeine, and paraxanthine. Pharmacodynamic response markers, heart rate and blood pressure, were recorded. Results: Theacrine pharmacokinetics was similar following administration of theacrine alone. Caffeine coadministration increased maximum plasma concentration and area under the curve of theacrine without altering theacrine half-life. Theacrine had no impact on caffeine or paraxanthine pharmacokinetics. There was no difference between treatment groups with regard to heart rate or systolic/diastolic blood pressure. Conclusions: Coadministration of theacrine and caffeine results in a clinically significant pharmacokinetic interaction, viz., increased theacrine exposure. Enhanced oral bioavailability is the most likely mechanism by which caffeine alters theacrine exposure. However, further studies examining the contribution of presystemic elimination mechanisms, for example, efflux transport and/or gut metabolism, to theacrine bioavailability are needed to confirm the exact mechanism(s). Hemodynamic parameters were unaltered despite the pharmacokinetic interaction, suggesting that coadministration of caffeine and theacrine is safe at the doses administered.

23 June 2014 in PLOS ONE
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Journal Article
Open access
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JTJordan J. Toutounchian
Jordan J. Toutounchian
JSJena Steinle
Jena Steinle
PMPatrudu S. Makena
Patrudu S. Makena
CWChristopher M. Waters
Christopher M. Waters
MWMatthew W. Wilson
Matthew W. Wilson
CYCharles Ryan Yates
Charles Ryan Yates
Radiation-induced damage to the retina triggers leukostasis, retinal endothelial cell (REC) death, and subsequent hypoxia. Resultant ischemia leads to visual loss and compensatory retinal neovascularization (RNV). Using human RECs, we demonstrated that radiation induced leukocyte adhesion through mechanisms involving p38MAPK, p53, and ICAM-1 activation. Additional phenotypic changes included p38MAPK-dependent tyrosine phosphorylation of the focal adhesion scaffolding protein, paxillin (Tyr118). The quinic acid derivative KZ-41 lessened leukocyte adhesion and paxillin-dependent proliferation via inhibition of p38MAPK-p53-ICAM-1 signaling. Using the murine oxygen-induced retinopathy (OIR) model, we examined the effect of KZ-41 on pathologic RNV. Daily ocular application of a KZ-41-loaded nanoemulsion significantly reduced both the avascular and neovascular areas in harvested retinal flat mounts when compared to the contralateral eye receiving vehicle alone. Our data highlight the potential benefit of KZ-41 in reducing both the retinal ischemia and neovascularization provoked by genotoxic insults. Further research into how quinic acid derivatives target and mitigate inflammation is needed to fully appreciate their therapeutic potential for the treatment of inflammatory retinal vasculopathies.

4 October 2013 in BMC Pharmacology and Toxicology
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Journal Article
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BSBrian K Schilling
Brian K Schilling
KHKelley G Hammond
Kelley G Hammond
RBRichard Bloomer
Richard Bloomer
CPChaela S Presley
Chaela S Presley
CYCharles Ryan Yates
Charles Ryan Yates
1,3-dimethylamylamine (DMAA) has been a component of dietary supplements and is also used within "party pills," often in conjunction with alcohol and other drugs. Ingestion of higher than recommended doses results in untoward effects including cerebral hemorrhage. To our knowledge, no studies have been conducted to determine both the pharmacokinetic profile and physiologic responses of DMAA.