Prophylactic benefits of systemically delivered simvastatin treatment in a house dust mite challenged murine model of allergic asthma.

BACKGROUND AND PURPOSE: Systemically delivered statins can blunt airway inflammation in ovalbumin-challenged mice. However, in asthma clinical trials the beneficial effects of introducing oral statins are not compelling. We have invetigated this discrepancy using a clinically relevant murine model of allergic asthma, and by including a prophylactic study arm. EXPERIMENTAL APPROACH: Adult mice were: 1) challenged with house dust mite (HDM) alone or with subcutaneous (s.c.) simvastatin for two weeks; or 2) also treated with simvastatin for one week prior to HDM challenge. We assayed lung function, inflammatory cell influx and cytokine profile, goblet cell abundance, and simvastatin concentration in serum, lung lavage and tissue. KEY RESULTS: Ultrahigh performance liquid chromatography-tandem mass spectrometry revealed that pharmacologically active simvastatin reached peak serum concentration after 8 h, but declined rapidly. Prophylactic treatment doubled peak serum simvastatin and repeated s.c. delivery established stable serum levels, but simvastatin was undetectable in the lungs. Both simvastatin treatment arms suppressed indices of HDM-induced airway inflammation and goblet cell hyperplasia, but this was significantly greater with prophylactic therapy, in particular, inhibition of neutrophil and eosinophil influx, and cytokine accumulation. Conversely, neither acute nor prophylactic delivery of simvastatin prevented HDM challenge-induced airway hyperreactivity. CONCLUSION AND IMPLICATIONS: Systemically administered simvastatin accumulates in the blood, but not in lung tissues, and reduces leukocyte influx and associated lung inflammation. Prophylactic therapy has the greatest anti-inflammatory effects, but as observed in human clinical trials, systemic simvastatin therapy does not prevent allergic airway hyperreactivity.

Late season pharmaceutical fate in wetland mesocosms with and without phosphorous addition.

The fate of six human-use drugs was assessed and predicted in mesocosms designed to mimic shallow constructed wetlands during the onset of fall and senescence. Mesocosms were monitored for 28 days after the addition of carbamazepine, clofibric acid, fluoxetine and naproxen (nominal initial concentrations of 5 µg/L each), sulfamethoxazole, and sulfapyridine (nominal initial concentrations of 150 µg/L each), with and without phosphorous (P) addition at 1.6 mg/L. We hypothesized that addition of P would stimulate primary productivity and enhance removal of pharmaceuticals from the water column. Carbamazepine, clofibric acid, fluoxetine, and naproxen had half-lives of 8.7, 11, 1.5, and 2.5, and 8.6, 11.0, 1.4, and 2.5 days in treatments with and without P amendment, respectively. Sulfamethoxazole and sulfapyridine had half-lives of 17 and 4.9 days in mesocosms with P amendment and 17 and 4.7 days without amendment. A concurrent pulse of P with pharmaceuticals did not significantly enhance the removal of these compounds. Predicted half-lives from modeling efforts were consistent with observed values, with photolysis the greatest contributor to chemical attenuation.

Direct UV photolysis of selected pharmaceuticals, personal care products and endocrine disruptors in aqueous solution.

Pharmaceuticals and personal care products (PPCPs), and endocrine disrupting compounds (EDCs) are micropollutants of emerging concern that have been detected in the aquatic environment and in some cases, in drinking water at nanogram per liter levels. The goal of this study was to evaluate the removal of 15 model PPCPs and EDCs from water by direct UV photolysis, using either low (LP)-or medium (MP) -pressure mercury vapor arc lamps. Some of the model compounds are either weak bases or weak acids, and therefore, the pKa values were determined or confirmed for those compounds using spectrophotometric titrations. The molar absorption coefficients of ionized and non-ionized forms were also determined. The quantum yields at 253.7 nm in phosphate buffer solutions of pH 7.2 were determined to be 0.033 ± 0.004 for sulfamethoxazole, 0.0035 ± 0.0008 for sulfachloropyridazine, 0.006 ± 0.002 for acetaminophen, 0.34 ± 0.07 for triclosan, 0.35 ± 0.14 for estrone, 0.08 ± 0.05 for 17α-ethinylestradiol, 0.086 ± 0.012 for ibuprofen. The quantum yield for 4-n-nonylphenol photolysis at 253.7 nm varied with the initial concentration from 0.32 ± 0.08 at 23 µg/L to 0.092 ± 0.006 at 230 µg/L. The pseudo-first order rate constants determined for direct photolysis at 253.7 nm of the studied micropollutants followed the order: triclosan ≈ sulfamethoxazole >> 4-n-nonylphenol ≈ sulfachloropyridazine ≈ estrone > acetaminophen ≈ 17α-ethinylestradiol ≈ ibuprofen. In contrast to the results observed for the monochromatic radiation (LP lamp), all 15 model compounds photolyzed under exposure to the broadband radiation emitted by the MP lamp.

Macrophytes may not contribute significantly to removal of nutrients, pharmaceuticals, and antibiotic resistance in model surface constructed wetlands.

Outdoor shallow wetland mesocosms, designed to simulate surface constructed wetlands to improve lagoon wastewater treatment, were used to assess the role of macrophytes in the dissipation of wastewater nutrients, selected pharmaceuticals, and antibiotic resistance genes (ARGs). Specifically, mesocosms were established with or without populations of Typha spp. (cattails), Myriophyllum sibiricum (northern water milfoil), and Utricularia vulgaris (bladderwort). Following macrophyte establishment, mesocosms were seeded with ARG-bearing organisms from a local wastewater lagoon, and treated with a single pulse of artificial municipal wastewater with or without carbamazepine, clofibric acid, fluoxetine, and naproxen (each at 7.6µg/L), as well as sulfamethoxazole and sulfapyridine (each at 150µg/L). Rates of pharmaceutical dissipation over 28d ranged from 0.073 to 3.0d(-1), corresponding to half-lives of 0.23 to 9.4d. Based on calculated rate constants, observed dissipation rates were consistent with photodegradation driving clofibric acid, naproxen, sulfamethoxazole, and sulfapyridine removal, and with sorption also contributing to carbamazepine and fluoxetine loss. Of the seven gene determinants assayed, only two genes for both beta-lactam resistance (blaCTX and blaTEM) and sulfonamide resistance (sulI and sulII) were found in sufficient quantity for monitoring. Genes disappeared relatively rapidly from the water column, with half-lives ranging from 2.1 to 99d. In contrast, detected gene levels did not change in the sediment, with the exception of sulI, which increased after 28d in pharmaceutical-treated systems. These shallow wetland mesocosms were able to dissipate wastewater contaminants rapidly. However, no significant enhancement in removal of nutrients or pharmaceuticals was observed in mesocosms with extensive aquatic plant communities. This was likely due to three factors: first, use of naïve systems with an unchallenged capacity for nutrient assimilation and contaminant removal; second, nutrient sequestration by ubiquitous filamentous algae; and third, dominance of photolytic processes in the removal of pharmaceuticals, which overshadowed putative plant-related processes.

Simultaneous quantification of simvastatin and simvastatin hydroxy acid in blood serum at physiological pH by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS).

Simvastatin attenuates airway inflammation and hyperreactivity, hallmarks of asthma, in allergen-challenged mice. As such, it is under consideration as a novel therapeutic, thus it is important to quantify the levels of simvastatin and its pharmacologically active and interconvertible metabolite, simvastatin hydroxy acid, that can be attained in the body. Methods exist to measure the concentrations of these compounds in biological media; however they do not maintain a physiological pH, and as a result do not accurately measure the ratio of these two compounds that exists in vivo. We developed a new method to measure simvastatin and simvastatin hydroxy acid more accurately in serum from mice by ultra high performance liquid chromatography-tandem mass spectrometry. We minimized the time that the compounds were in aqueous solution, and buffered samples to a physiological pH value of 7.4. Limits of quantification (LOQ) were 0.16 ng mL(-1) extract (1.3 ng mL(-1) serum) for simvastatin, and 8.3 ng mL(-1) extract (66 ng mL(-1) serum) for simvastatin hydroxy acid, respectively. No interconversion was observed, based on spike-and-recovery experiments of solutions containing both compounds. The method was applied using biological samples from mice challenged with house dust mite extract and simultaneously treated with subcutaneous simvastatin injection. Simvastatin hydroxy acid concentrations became significantly increased after a 2 week pre-treatment regime, whereas simvastatin concentrations were below the LOQ for all serum samples.

Performance of a constructed wetland in Grand Marais, Manitoba, Canada: Removal of nutrients, pharmaceuticals, and antibiotic resistance genes from municipal wastewater.

BACKGROUND: The discharge of complex mixtures of nutrients, organic micropollutants, and antibiotic resistance genes from treated municipal wastewater into freshwater systems are global concerns for human health and aquatic organisms. Antibiotic resistance genes (ARGs) are genes that have the ability to impart resistance to antibiotics and reduce the efficacy of antibiotics in the systems in which they are found. In the rural community of Grand Marais, Manitoba, Canada, wastewater is treated passively in a sewage lagoon prior to passage through a treatment wetland and subsequent release into surface waters. Using this facility as a model system for the Canadian Prairies, the two aims of this study were to assess: (a) the presence of nutrients, micropollutants (i.e., pesticides, pharmaceuticals), and ARGs in lagoon outputs, and (b) their potential removal by the treatment wetland prior to release to surface waters in 2012. RESULTS: As expected, concentrations of nitrogen and phosphorus species were greatest in the lagoon and declined with movement through the wetland treatment system. Pharmaceutical and agricultural chemicals were detected at concentrations in the ng/L range. Concentrations of these compounds spiked downstream of the lagoon following discharge and attenuation was observed as the effluent migrated through the wetland system. Hazard quotients calculated for micropollutants of interest indicated minimal toxicological risk to aquatic biota, and results suggest that the wetland attenuated atrazine and carbamazepine significantly. There was no significant targeted removal of ARGs in the wetland and our data suggest that the bacterial population in this system may have genes imparting antibiotic resistance. CONCLUSIONS: The results of this study indicate that while the treatment wetland may effectively attenuate excess nutrients and remove some micropollutants and bacteria, it does not specifically target ARGs for removal. Additional studies would be beneficial to determine whether upgrades to extend retention time or alter plant community structure within the wetland would optimize removal of micropollutants and ARGs to fully characterize the utility of these systems on the Canadian Prairies.

Presence and hazards of nutrients and emerging organic micropollutants from sewage lagoon discharges into Dead Horse Creek, Manitoba, Canada.

Nutrient enrichment and loadings of pharmaceuticals and agrochemicals into freshwater systems are common concerns, especially for water bodies receiving wastewater inputs. In the rural communities of Morden and Winkler of Manitoba, Canada, sewage lagoons discharge their wastewater directly into Dead Horse Creek, a small tributary of the Red River that empties into Lake Winnipeg. This lagoon approach to managing rural wastewaters is common across the North American Prairies. Therefore, this study aimed to assess the hazards of lagoon treatment releases at this model site. This was done by characterizing the nutrients, organic micropollutants (i.e., pesticides, pharmaceuticals) and standard water quality parameters in the creek prior to and following lagoon discharge events over a number of years (2009-2011). Measured concentrations of nutrients were compared to regulatory expectations and micropollutants were assessed using hazard quotients. As expected, concentrations of nitrogen and phosphorus species were greatest in sites downstream of the sewage outfall immediately following discharge events. Pharmaceutical and agricultural chemicals were detected at concentrations between 0.5 and 90 ng/L. Detection frequencies and concentrations matched typical use patterns. Those compounds used predominately for human medicine were detected at downstream sites following discharge events, while those used in an agricultural setting were detected at relatively consistent levels over time at sites both upstream and downstream of the outfall location. Hazard quotients calculated for micropollutants of interest indicated minimal toxicological risk to aquatic biota in the creek, with only erythromycin and diazinon presenting a potential concern to aquatic algae and invertebrates. Concentrations of nutrients exceeded Canadian guideline thresholds during release, but returned to background levels once discharges ceased. Therefore, it is advisable that wastewater treatment and management strategies such as constructed wetlands and/or staggered releases be used in order to minimize the hazard posed by nutrient pulses in Dead Horse Creek and other similar systems.

Stability of pharmaceuticals and other polar organic compounds stored on polar organic chemical integrative samplers and solid-phase extraction cartridges.

The stability of 24 chemicals, including pharmaceuticals and personal care products, and some agrochemicals on extraction media was evaluated by preloading them onto Oasis hydrophilic lipophilic balanced solid-phase extraction (SPE) cartridges and polar organic chemical integrative samplers (POCIS) followed by storage at -20°C over time. After 20 months, the average loss was 11% on POCIS, with only 2,4-dichlorophenoxyacetic acid, atrazine, chlorpyrifos, and gemfibrozil showing a statistically significant decline compared with initial concentrations. Losses on SPE cartridges were below 19%, with an average loss of 9%. In addition to laboratory spiked samples, multiple POCIS deployed in wastewater-impacted surface waters and SPE extracts of these waters were stored in their original coextracted matrix for nearly two years with minimal observed losses. Errors from typical sampling, handling, and concentration estimates from POCIS sampling rates were typically ± 15 to 30% relative standard deviation, so observed storage losses are minimal for most POCIS applications. While losses during storage on SPE cartridges for 20 months were small but statistically significant for many compounds, addition of labeled internal standards prior to freezing should correct for such losses. Thus, storage of processed water samples for analysis of polar organic pollutants is viable for archival purposes or studies for which samples cannot be analyzed in the short term.

Dissipation kinetics and mobility of chlortetracycline, tylosin, and monensin in an agricultural soil in Northumberland County, Ontario, Canada.

A robust high-throughput method was refined to extract three growth-promoting antibiotics, tylosin (TYL), chlortetracycline (CTC), and monensin (MON), from soil. Analysis was performed by electrospray liquid chromatography tandem mass spectrometry. Soil dissipation rate studies were performed in a farm field soil for antibiotics applied with and without manure. Tylosin, CTC, and MON followed first-order dissipation kinetics with half-lives of 4.5, 24, and 3.3 d, respectively, with the addition of manure and 6.1, 21, and 3.8 d, respectively, without manure. Manure application significantly increased TYL dissipation rate, perhaps because of the introduced microbial flora, but had no significant effect on CTC or MON. Monensin dissipation half-life was found to be much shorter in the field study than in a controlled laboratory study, perhaps because of differences in microbial communities. The antimicrobials were not highly mobile. Chlortetracycline was the only antibiotic detected at 25 to 35 cm depth and only up to 2% of the initial concentration in a sandy loam soil. These antibiotics are therefore expected to degrade primarily in agricultural soils before moving to greater depths or to groundwater in significant concentrations in most agricultural systems.