Acetylcholine-induced vasorelaxation (AChIR) and responses to reduced pO
(hypoxia-induced relaxation (HIR), 0% O
) were assessed in vitro in aortic rings of healthy male Sprague-Dawley rats (N = 252) ...under hyperbaric (HBO
) protocols. The studied groups consisted of the CTRL group (untreated); the A-HBO
group (single HBO
; 120 min of 100% O
at 2.0 bars); the 24H-HBO
group (examined 24 h after single exposure) and the 4D-HBO
group (four consecutive days of single HBO
). AChIR, sensitivity to ACh and iNOS expression were decreased in the A-HBO
group. HIR was prostanoid- and epoxyeicosatrienoic acid (EET)-mediated. HIF-1α expression was increased in the 24H-HBO
and 4D-HBO
groups. LW6 (HIF-1α inhibitor) decreased HIR in the 24H-HBO
group. HBO
affected the expression of COX-1 and COX-2. CYP2c11 expression was elevated in the 24H-HBO
and 4D-HBO
groups. Concentrations of arachidonic acid (AA) metabolites 14(15)-DiHET, 11(12)-DiHET and 8(9)-DiHET were increased in A-HBO
and 24H-HBO
An increased concentration of 8(9)-EET was observed in the A-HBO
and 24h-HBO
groups vs. the CTRL and 4D-HBO
groups, and an increased concentration of 5(6)-DiHET was observed in the 24H-HBO
group vs. the 4D-HBO
group. The 20-HETE concentration was increased in the A-HBO
group. All were determined by LC-MS/MS of the aorta. The results show that AChIR in all groups is mostly NO-dependent. HIR is undoubtedly mediated by the CYP450 enzymes' metabolites of AA, whereas HIF-1α contributes to restored HIR. Vasoconstrictor metabolites of CYP450 enzymes contribute to attenuated AChIR and HIR in A-HBO
.
Unrestricted increased table salt (NaCl) intake is associated with oxidative stress and inflammation, leading to endothelial dysfunction and atherosclerosis. However, data on salt-induced ...immunomodulatory effects in the earliest phase of salt loading are scarce.
In the present study, an animal model of short-term salt loading was employed, including male Sprague Dawley rats consuming a high-salt diet (HSD; 4% NaCl) or standard laboratory chow (low-salt; LSD; 0.4% NaCl) during a 7-day period. The contribution of angiotensin II (ANGII) suppression was tested by adding a group of rats on a high-salt diet receiving ANGII infusions
Samples of peripheral blood/mesenteric lymph node leukocytes, brain blood vessels, and serum samples were processed for flow cytometry, quantitative real-time PCR, total proteome analysis, and multiplex immunoassay.
Data analysis revealed the up-regulation of Il 6 gene in the microcirculation of high-salt-fed rats, accompanied by an increased serum level of TNF-alpha cytokine. The high-salt diet resulted in increased proportion of serum mono-unsaturated fatty acids and saturated fatty acids, reduced levels of linoleic (C18:2 ω-6) and α-linolenic (C18:3 ω-3) acid, and increased levels of palmitoleic acid (C16:1 ω-7). The high-salt diet had distinct, lymphoid compartment-specific effects on leukocyte subpopulations, which could be attributed to the increased expression of salt-sensitive SGK-1 kinase. Complete proteome analysis revealed high-salt-diet-induced vascular tissue remodeling and perturbations in energy metabolism. Interestingly, many of the observed effects were reversed by ANGII supplementation.
Low-grade systemic inflammation induced by a HSD could be related to suppressed ANGII levels. The effects of HSD involved changes in Th17 and Treg cell distribution, vascular wall remodeling, and a shift in lipid and arachidonic acid metabolism.
Macrolides with 14- and 15-membered ring are characterized by high and extensive tissue distribution, as well as good cellular accumulation and retention. Since macrolide structures do not fit the ...Lipinski rule of five, macrolide pharmacokinetic properties cannot be successfully predicted by common models based on data for small molecules. Here we describe the development of the first models for macrolide cellular pharmacokinetics. By comparison of cellular accumulation and retention in six human primary cell cultures of leukocytic and lung origin, as well as in lung carcinoma cell line NCI-H292, this cell line was found to be an adequate representative cell type for modeling macrolide cellular pharmacokinetics. Accumulation and retention in the NCI-H292 cells, as well as various physicochemical properties, were determined for a set of 48 rationally designed basic macrolide compounds. Classification models for predicting macrolide cellular accumulation and retention were developed using relatively easily determined and conceptually simple descriptors: experimentally determined physicochemical parameters ChromlogD and CHI IAM, as well as a calculated number of positively charged atoms (POS). The models were further tested and improved by addition of 37 structurally diverse macrolide molecules.
Macrolide antibiotics, like erythromycin, clarithromycin, and azithromycin, possess anti-inflammatory properties. These properties are considered fundamental to the efficacy of these three macrolides ...in the treatment of chronic inflammatory diseases like diffuse panbronchiolitis and cystic fibrosis. However, long-term treatment with macrolide antibiotics presents a considerable risk for promotion of bacterial resistance. We have examined antibacterial and anti-inflammatory effects of a novel macrolide class: N'-substituted 2'-O,3'-N-carbonimidoyl bridged erythromycin-derived 14- and 15-membered macrolides. A small focused library was prepared, and compounds without antimicrobial activity, which inhibited IL-6 production, were selected. Data analysis led to a statistical model that could be used for the design of novel anti-inflammatory macrolides. The most promising compound from this library retained the anti-inflammatory activity observed with azithromycin in lipopolysaccharide-induced pulmonary neutrophilia in vivo. Importantly, this study strongly suggests that antimicrobial and anti-inflammatory activities of macrolides are independent and can be separated, which raises development plausibility of novel anti-inflammatory therapeutics.
Two nanostructured sol–gel TiO
2
films were prepared on a glass substrate by means of the dip-coating technique with titanium (IV) isopropoxide as a precursor with and without the addition of ...polyethylene glycol (PEG) as a structure-directing agent. The synthesized films were characterized by using thermal gravimetry, differential scanning calorimetry, micro-Raman spectroscopy, and atomic force microscopy (AFM). Results of the AFM analysis revealed that both films are nanostructured and that the TiO
2
film prepared with the addition of PEG has higher values of roughness. The photocatalytic activity of the films was evaluated by the photocatalytic degradation of the methyl orange monoazo dye and the congo red diazo dye with predominant radiation wavelengths of 365 nm (UV-A) and 254 nm (UV-C). The effects of temperature (17.5, 25 and 35 °C) on the film stability and on the degradation process were also followed. The TiO
2
film created with the addition of PEG showed heightened photoactivity at all reaction temperatures and higher degradation rates of both dyes were observed with the UV-C than with the UV-A radiation. In some cases, the total decolorization process was complete in 90 or 120 min, but the total mineralization of the dye solutions was not achieved after 120 min. The TiO
2
films were stable at all three temperatures after more than 50 working hours. The degradation processes of dyes were monitored by means of the UV/VIS spectrophotometry and the liquid chromatography mass spectrometry together with the total organic carbon.
The purpose of this study was to evaluate the impact of structural modifications on the 15-membered macrolactone ring and/or substituents on the in vitro ADME properties and in vivo pharmacokinetic ...(PK) profile for selected derivatives in rodents in comparison to azithromycin. Azithromycin and seven selected 15-membered macrolide derivatives, modified either by removal of the sugar moieties, replacement of the amine with a lactam, or addition of lipophilic substituents, were screened in several in vitro ADME assays and in vivo PK studies in rodents. In vitro ADME profiling included assessment of passive permeability and P-gp substrate, metabolic stability in liver microsomes and hepatocytes, as well as CYP direct inhibition measurements. In vivo PK studies were performed in rats (Sprague–Dawley), mice (Balb/c), and P-gp wild-type and deficient mice (CF-1™). Different structural modifications on the azithromycin scaffold resulted in substantial changes in disposition kinetics and oral bioavailability in both rodent species. However, these differences in vivo cannot be predicted based on in vitro results since most of these molecules are classified in the same category. Therefore, in the case of 15-membered ring macrolides, the in vitro ADME screens presented here seem to have low predictive value for in vivo prediction, making their use as routine in vitro screens prior to PK assessments questionable.
Generation of amyloid-β peptides (Aβs) by proteolytic cleavage of the amyloid-β protein precursor (AβPP), especially increased production of Aβ42/Aβ43 over Aβ40, and their aggregation as oligomers ...and plaques, represent a characteristic feature of Alzheimer's disease (AD). In familial AD (FAD), altered Aβ production originates from specific mutations of AβPP or presenilins 1/2 (PS1/PS2), the catalytic subunits of γ-secretase. In sporadic AD, the origin of altered production of Aβs remains unknown. We hypothesize that the 'human chemical exposome' contains products able to favor the production of Aβ42/Aβ43 over Aβ40 and shorter Aβs. To detect such products, we screened a library of 3500 + compounds in a cell-based assay for enhanced Aβ42/Aβ43 production. Nine pyrazole insecticides were found to induce a β- and γ-secretase-dependent, 3-10-fold increase in the production of extracellular Aβ42 in various cell lines and neurons differentiated from induced pluripotent stem cells derived from healthy and FAD patients. Immunoprecipitation/mass spectrometry analyses showed increased production of Aβs cleaved at positions 42/43, and reduced production of peptides cleaved at positions 38 and shorter. Strongly supporting a direct effect on γ-secretase activity, pyrazoles shifted the cleavage pattern of another γ-secretase substrate, alcadeinα, and shifted the cleavage of AβPP by highly purified γ-secretase toward Aβ42/Aβ43. Focusing on fipronil, we showed that some of its metabolites, in particular the persistent fipronil sulfone, also favor the production of Aβ42/Aβ43 in both cell-based and cell-free systems. Fipronil administered orally to mice and rats is known to be metabolized rapidly, mostly to fipronil sulfone, which stably accumulates in adipose tissue and brain. In conclusion, several widely used pyrazole insecticides enhance the production of toxic, aggregation prone Aβ42/Aβ43 peptides, suggesting the possible existence of environmental "Alzheimerogens" which may contribute to the initiation and propagation of the amyloidogenic process in sporadic AD.
A series of 4''-O-acyl derivatives of 8a-aza-8a-homoerythromycins A were synthesized and tested against Gram-positive and Gram-negative bacteria. Derivatives of 8a-aza-8a-homoerythromycin A have ...potent anti-bacterial activity against not only azithromycin-susceptible strains, but also efflux (M) and inducible macrolide-lincosamide-streptogramin-resistant Gram-positive pathogens. These compounds show moderate to high clearance and low oral bioavailability in preliminary in vivo pharmacokinetic studies in rat.
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