Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: Minarchick VC[original query] |
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Cardiac and mitochondrial dysfunction following acute pulmonary exposure to mountaintop removal mining particulate matter
Nichols CE , Shepherd DL , Knuckles TL , Thapa D , Stricker JC , Stapleton PA , Minarchick VC , Erdely A , Zeidler-Erdely PC , Alway SE , Nurkiewicz TR , Hollander JM . Am J Physiol Heart Circ Physiol 2015 309 (12) ajpheart 00353 2015 Throughout the United States, air pollution correlates with adverse health outcomes and cardiovascular disease incidence is commonly increased following environmental exposure. In areas surrounding active mountaintop removal mines (MTM) a further increase in cardiovascular morbidity is observed and may be attributed in part to particulate matter (PM) released from the mine. The mitochondrion has been shown to be central in the etiology of many cardiovascular diseases, yet its role in PM related cardiovascular effects are not realized. In this study we sought to elucidate the cardiac processes that are disrupted following exposure to mountaintop removal mining particulate matter (PMMTM). To address this question we exposed male Sprague-Dawley rats to PMMTM, collected within one mile of an active MTM site, using intratracheal instillation. Twenty-four hours following exposure we evaluated cardiac function, apoptotic indices and mitochondrial function. PMMTM exposure, elicited a significant decrease in ejection fraction and fractional shortening compared to controls. Investigation into the cellular impacts of PMMTM exposure identified a significant increase in mitochondrial-induced apoptosis as reflected by an increase in TUNEL positive nuclei and increased caspase-3 and -9 activities. Finally, a significant increase in mitochondrial transition pore opening leading to decreased mitochondrial function was identified following exposure. In conclusion, our data suggest that pulmonary exposure to PMMTM increases cardiac mitochondrial-associated apoptosis and decreases mitochondrial function concomitant with decreased cardiac function. These results suggest that increased cardiovascular disease incidence in populations surrounding MTM mines may be associated with increased cardiac cell apoptosis and decreased mitochondrial function. |
Temporal changes in rat liver gene expression after acute cadmium and chromium exposure.
Madejczyk MS , Baer CE , Dennis WE , Minarchick VC , Leonard SS , Jackson DA , Stallings JD , Lewis JA . PLoS One 2015 10 (5) e0127327 ![]() U.S. Service Members and civilians are at risk of exposure to a variety of environmental health hazards throughout their normal duty activities and in industrial occupations. Metals are widely used in large quantities in a number of industrial processes and are a common environmental toxicant, which increases the possibility of being exposed at toxic levels. While metal toxicity has been widely studied, the exact mechanisms of toxicity remain unclear. In order to further elucidate these mechanisms and identify candidate biomarkers, rats were exposed via a single intraperitoneal injection to three concentrations of CdCl2 and Na2Cr2O7, with livers harvested at 1, 3, or 7 days after exposure. Cd and Cr accumulated in the liver at 1 day post exposure. Cd levels remained elevated over the length of the experiment, while Cr levels declined. Metal exposures induced ROS, including hydroxyl radical (*OH), resulting in DNA strand breaks and lipid peroxidation. Interestingly, ROS and cellular damage appeared to increase with time post-exposure in both metals, despite declines in Cr levels. Differentially expressed genes were identified via microarray analysis. Both metals perturbed gene expression in pathways related to oxidative stress, metabolism, DNA damage, cell cycle, and inflammatory response. This work provides insight into the temporal effects and mechanistic pathways involved in acute metal intoxication, leading to the identification of candidate biomarkers. |
Acute inflammatory responses of nanoparticles in an intra-tracheal instillation rat model
Armstead AL , Minarchick VC , Porter DW , Nurkiewicz TR , Li B . PLoS One 2015 10 (3) e0118778 Exposure to hard metal tungsten carbide cobalt (WC-Co) "dusts" in enclosed industrial environments is known to contribute to the development of hard metal lung disease and an increased risk for lung cancer. Currently, the influence of local and systemic inflammation on disease progression following WC-Co exposure remains unclear. To better understand the relationship between WC-Co nanoparticle (NP) exposure and its resultant effects, the acute local pulmonary and systemic inflammatory responses caused by WC-Co NPs were explored using an intra-tracheal instillation (IT) model and compared to those of CeO2 (another occupational hazard) NP exposure. Sprague-Dawley rats were given an IT dose (0-500 mug per rat) of WC-Co or CeO2 NPs. Following 24-hr exposure, broncho-alveolar lavage fluid and whole blood were collected and analyzed. A consistent lack of acute local pulmonary inflammation was observed in terms of the broncho-alveolar lavage fluid parameters examined (i.e. LDH, albumin, and macrophage activation) in animals exposed to WC-Co NP; however, significant acute pulmonary inflammation was observed in the CeO2 NP group. The lack of acute inflammation following WC-Co NP exposure contrasts with earlier in vivo reports regarding WC-Co toxicity in rats, illuminating the critical role of NP dose and exposure time and bringing into question the potential role of impurities in particle samples. Further, we demonstrated that WC-Co NP exposure does not induce acute systemic effects since no significant increase in circulating inflammatory cytokines were observed. Taken together, the results of this in vivo study illustrate the distinct differences in acute local pulmonary and systemic inflammatory responses to NPs composed of WC-Co and CeO2; therefore, it is important that the outcomes of pulmonary exposure to one type of NPs may not be implicitly extrapolated to other types of NPs. |
Intravenous and gastric cerium dioxide nanoparticle exposure disrupts microvascular smooth muscle signaling
Minarchick VC , Stapleton PA , Fix NR , Leonard SS , Sabolsky EM , Nurkiewicz TR . Toxicol Sci 2014 144 (1) 77-89 Cerium dioxide nanoparticles (CeO2 NP) hold great therapeutic potential, but the in vivo effects of non-pulmonary exposure routes are unclear. The first aim was to determine whether microvascular function is impaired after intravenous and gastric CeO2 NP exposure. The second aim was to investigate the mechanism(s) of action underlying microvascular dysfunction following CeO2 NP exposure. Rats were exposed to CeO2 NP (primary diameter: 4 +/- 1 nm, surface area: 81.36 m2/g) by intratracheal instillation, intravenous injection, or gastric gavage. Mesenteric arterioles were harvested 24 h post-exposure and vascular function was assessed using an isolated arteriole preparation. Endothelium-dependent and -independent function and vascular smooth muscle (VSM) signaling [soluble guanylyl cyclase (sGC), and cyclic guanosine monophosphate (cGMP)] were assessed. Reactive oxygen species (ROS) generation and nitric oxide (NO) production were analyzed. Compared to controls, endothelium-dependent and -independent dilation were impaired following intravenous injection (by 61% and 45%) and gastric gavage (by 63% and 49%). However, intravenous injection resulted in greater microvascular impairment (16% and 35%) compared to gastric gavage at an identical dose (100 mug). Furthermore, sGC activation and cGMP responsiveness were impaired following pulmonary, intravenous, and gastric CeO2 NP treatment. Finally, nanoparticle exposure resulted in route-dependent, increased ROS generation and decreased NO production. These results indicate that CeO2 NP exposure route differentially impairs microvascular function, which may be mechanistically linked to decreased NO production and subsequent VSM signaling. Fully understanding the mechanisms behind CeO2 NP in vivo effects is a critical step in the continued therapeutic development of this nanoparticle. |
Pulmonary cerium dioxide nanoparticle exposure differentially impairs coronary and mesenteric arteriolar reactivity
Minarchick VC , Stapleton PA , Porter DW , Wolfarth MG , Ciftyurek E , Barger M , Sabolsky EM , Nurkiewicz TR . Cardiovasc Toxicol 2013 13 (4) 323-37 Cerium dioxide nanoparticles (CeO2 NPs) are an engineered nanomaterial (ENM) that possesses unique catalytic, oxidative, and reductive properties. Currently, CeO2 NPs are being used as a fuel catalyst but these properties are also utilized in the development of potential drug treatments for radiation and stroke protection. These uses of CeO2 NPs present a risk for human exposure; however, to date, no studies have investigated the effects of CeO2 NPs on the microcirculation following pulmonary exposure. Previous studies in our laboratory with other nanomaterials have shown impairments in normal microvascular function after pulmonary exposures. Therefore, we predicted that CeO2 NP exposure would cause microvascular dysfunction that is dependent on the tissue bed and dose. Twenty-four-hour post-exposure to CeO2 NPs (0-400 mug), mesenteric, and coronary arterioles was isolated and microvascular function was assessed. Our results provided evidence that pulmonary CeO2 NP exposure impairs endothelium-dependent and endothelium-independent arteriolar dilation in a dose-dependent manner. The CeO2 NP exposure dose which causes a 50 % impairment in arteriolar function (EC50) was calculated and ranged from 15 to 100 mug depending on the chemical agonist and microvascular bed. Microvascular assessments with acetylcholine revealed a 33-75 % reduction in function following exposure. Additionally, there was a greater sensitivity to CeO2 NP exposure in the mesenteric microvasculature due to the 40 % decrease in the calculated EC50 compared to the coronary microvasculature EC50. CeO2 NP exposure increased mean arterial pressure in some groups. Taken together, these observed microvascular changes may likely have detrimental effects on local blood flow regulation and contribute to cardiovascular dysfunction associated with particle exposure. |
Glutathione conjugation of busulfan produces a hydroxyl radical-trapping dehydroalanine metabolite
Peer CJ , Younis IR , Leonard SS , Gannett PM , Minarchick VC , Kenyon AJ , Rojanasakul Y , Callery PS . Xenobiotica 2012 42 (12) 1170-7 The Phase 2 drug metabolism of busulfan yields a glutathione conjugate that undergoes a beta-elimination reaction. The elimination product is an electrophilic metabolite that is a dehydroalanine-containing tripeptide, gamma-glutamyldehydroalanylglycine (EdAG). In the process, glutathione lacks thiol-related redox properties and gains a radical scavenging dehydroalanine group. EdAG scavenged hydroxyl radical generated in the Fenton reaction in a concentration-dependent manner was monitored by electron paramagnetic resonance (EPR) spectroscopy. The apparent rate of hydroxyl radical scavenging was in the same range as published values for known antioxidants, including N-acyl dehydroalanines. A captodatively stabilized carbon-centered radical intermediate was spin trapped in the reaction of EdAG with hydroxyl radical. The proposed structure of a stable product in the Fenton reaction with EdAG was consistent with that of a gamma-glutamylserylglycyl dimer. Observation of the hydroxyl trapping properties of EdAG suggests that the busulfan metabolite EdAG may contribute to or mitigate redox-related cytotoxicity associated with the therapeutic use of busulfan, and reaffirms indicators that support a role in free radical biology for dehydroalanine-containing peptides and proteins. |
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