Browsing by Author "Wisniewski, Natalie A"

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    Antibiotic-induced changes in the microbiota disrupt redox dynamics in the gut.
    (eLife, 2018-06-19) Reese, Aspen T; Cho, Eugenia H; Klitzman, Bruce; Nichols, Scott P; Wisniewski, Natalie A; Villa, Max M; Durand, Heather K; Jiang, Sharon; Midani, Firas S; Nimmagadda, Sai N; O'Connell, Thomas M; Wright, Justin P; Deshusses, Marc A; David, Lawrence A
    How host and microbial factors combine to structure gut microbial communities remains incompletely understood. Redox potential is an important environmental feature affected by both host and microbial actions. We assessed how antibiotics, which can impact host and microbial function, change redox state and how this contributes to post-antibiotic succession. We showed gut redox potential increased within hours of an antibiotic dose in mice. Host and microbial functioning changed under treatment, but shifts in redox potentials could be attributed specifically to bacterial suppression in a host-free ex vivo human gut microbiota model. Redox dynamics were linked to blooms of the bacterial family Enterobacteriaceae. Ecological succession to pre-treatment composition was associated with recovery of gut redox, but also required dispersal from unaffected gut communities. As bacterial competition for electron acceptors can be a key ecological factor structuring gut communities, these results support the potential for manipulating gut microbiota through managing bacterial respiration.
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    Tissue-Integrating Oxygen Sensors: Continuous Tracking of Tissue Hypoxia.
    (Advances in experimental medicine and biology, 2017-01) Wisniewski, Natalie A; Nichols, Scott P; Gamsey, Soya J; Pullins, Steve; Au-Yeung, Kit Y; Klitzman, Bruce; Helton, Kristen L
    We describe a simple method of tracking oxygen in real-time with injectable, tissue-integrating microsensors. The sensors are small (500 μm × 500 μm × 5 mm), soft, flexible, tissue-like, biocompatible hydrogel s that have been shown to overcome the foreign body response for long-term sensing. The sensors are engineered to change luminescence in the presence of oxygen or other analytes and function for months to years in the body. A single injection followed by non-invasive monitoring with a hand-held or wearable Bluetooth optical reader enables intermittent or continuous measurements. Proof of concept for applications in high altitude, exercise physiology, vascular disease, stroke, tumors, and other disease states have been shown in mouse, rat and porcine models. Over 90 sensors have been studied to date in humans. These novel tissue-integrating sensors yield real-time insights in tissue oxygen fluctuations for research and clinical applications.