Intestinal toxicity of ketoprofen-trometamol vs its enantiomers in rat. Role of oxidative stress

Thermally Latent Bases in Dynamic Covalent Polymer Networks and their Emerging Applications

A novel strategy allowing temporal control of dynamic bond exchange in covalently crosslinked polymer networks via latent transesterification catalysts is introduced. Obtained by a straightforward air- and water-tolerant synthesis, the latent catalyst is designed for an irreversible temperature-mediated release of a strong organic base. Its long-term inactivity at temperatures below 50 °C provides the unique opportunity to equip dynamic covalent networks with creep resistance and high bond-exchange rates, once activated. The presented thermally latent base catalyst is conveniently introducible in readily available building blocks and, as proof of concept, applied in a radically polymerized thiol-ene network. Light-mediated curing is used for 3D-printing functional objects, on which the possibility of spatially controlled reshaping and welding based on dynamic transesterification is illustrated. Since the catalyst is thermally activated, limitations regarding sample geometry and optical transparency do not apply, which facilitates a transfer to well-established industrial technologies. Consequently, fiber-reinforced and highly filled magneto-active thiol-ene polymer composites are fabricated by a thermal curing approach. The on-demand activation of dynamic transesterification is demonstrated by (magneto-assisted) reshaping experiments, highlighting a wide range of potential future applications offered by the presented concept.

Tricholoma matsutake-Derived Peptides Show Gastroprotective Effects against Ethanol-Induced Acute Gastric Injury

Acute gastric injury caused by ethanol is a frequent disorder of the gastrointestinal tract. In this study, we investigated the potential gastroprotective effects of Tricholoma matsutake-derived peptides against ethanol-triggered acute gastric injury and the associated mechanisms. Peptides SDLKHFPF and SDIKHFPF significantly attenuated the ethanol-induced decrease in GES-1 cell survival (82.39 ± 1.93 and 80.10 ± 1.08% vs 56.58 ± 1.86%), inhibited GES-1 cell apoptosis, and alleviated the ethanol-induced gastric mucosal injury (64.76 ± 3.98 and 49.29 ± 3.25%), ulcer index (3.33 ± 0.47 and 4.67 ± 0.47 vs 6.67 ± 0.47), and histopathological changes in mice. Peptide treatment inhibited the phosphorylation and nuclear translocation of nuclear factor kappa B (NF-κB), the secretion of tumor necrosis factor-α, interleukin-6, and endothelin-1. In addition, T. matsutake peptide pretreatment increased growth factor secretion, upregulated B-cell lymphoma-2, downregulated Bcl-2-associated X (Bax), and cleaved cysteinyl aspartate specific proteinase 3, thereby promoting gastric cell survival. These findings strongly suggest that T. matsutake peptides attenuate ethanol-induced inflammatory responses and apoptosis by suppressing NF-κB signaling activation, thereby enhancing gastric epithelial barrier functions.

Evaluation of histophysiological alterations associated with ketoprofen administration in albino NMRI mice

The aim of this study was to investigate the changes caused by the administration of ketoprofen to albino NMRI mice on some hematological, biochemical, and structural parameters. For this purpose, the mice were divided into two lots: a control batch and an experimental batch to which ketoprofen was administered subcutaneously at a dose of 10 mg/kg body weight per day for 7 days. A decrease in erythrocyte number and hemoglobin was observed altogether with the increase in white blood cells. Blood biochemistry indicates increased blood glucose, cholesterol, and triglyceride levels. Enzyme values (AST, ALT, and ALP) show a significant increase. Hepatic pathology reveals the enlargement of sinusoidal capillaries, the presence of leukocyte infiltrates associated with necrosis zones.

Protocatechuic acid-mediated DJ-1/PARK7 activation followed by PI3K/mTOR signaling pathway activation as a novel mechanism for protection against ketoprofen-induced oxidative damage in the gastrointestinal mucosa

Oxidative stress contributes to the progression of non-steroidal anti-inflammatory drug (NSAID)-induced gastrointestinal (GI) cell apoptosis. In our previous study, we reported that nuclear factor erythroid 2-related factor 2 (Nrf2) plays a protective role against ketoprofen-induced GI mucosal oxidative injury. Recent reports suggest that Nrf2 could exhibit antioxidative and antiapoptosis responses through up-regulation of DJ-1 (PARK7). In the current study, we proposed that induction of DJ-1 expression by protocatechuic acid (PCA) might provide a potential therapeutic approach for treating oxidative stress-associated GI ulcer diseases. The results indicated that PCA increased mRNA expression of glutathione peroxidase and heme oxygenase-1 through up-regulation of DJ-1 followed by Nrf2 translocation. Furthermore, PCA protected Int-407 cells against ketoprofen-induced oxidative stress by regulating the DJ-1, PI3K, and mTOR pathways. Pretreatment with PCA inhibited mitochondrial ROS generation, up-regulated the mitochondrial membrane potential, and down-regulated pro-apoptotic Bax as well as downstream caspase-8, caspase-9, and caspase-3 activity, and reversed impaired DJ-1 and anti-apoptotic Bcl-2 protein expression in Int-407 cells induced by ketoprofen. Similar to the in vitro results, SD rats treated with PCA before administration of ketoprofen exhibited decreased caspase-3 protein expression as well as oxidative damage, and impairment of the antioxidant system and DJ-1 protein expression in the GI mucosa were reversed. The administration of lansoprazole, a type of proton pump inhibitor (PPI), strongly inhibited ketoprofen-induced GI mucosal injuries via up-regulation of DJ-1, indicating that DJ-1 is essential for the dietary antioxidant- and PPI drug-mediated mechanism of ulcer therapy. These results suggest that DJ-1 could be a novel target for protection against ketoprofen-induced GI ulcers due to its antioxidant and anti-apoptosis characteristics.

Biotransformation and oxidative stress responses in rat hepatic cell-line (H4IIE) exposed to racemic ketoprofen (RS-KP) and its enantiomer, dexketoprofen (S(+)-KP)

Pharmaceuticals such as racemate ketoprofen (RS-KP) and its enantiomer, dexketoprofen (S(+)-KP) are highly detectable non-steroidal anti-inflammatory drugs (NSAIDs) in the aquatic environment and therefore are designated as one of the most emerging groups of pollutants that can affect environmental and human health. The potential impact of these pharmaceuticals was assessed for the first time in vitro using a rat hepatocellular carcinoma cell line (H4IIE). Cells were exposed to low and high concentrations of these drugs. Cytotoxicity was determined by MTT reduction assay; CYP1A1 transcriptional and enzymatic levels together with canonical oxidative stress responsive markers (GPx, GR, GST and CAT) were also investigated. Cells exposed to RS-KP and S(+)-KP did not show cytotoxicity effect at the concentrations tested. However, this study highlighted differences between RS-KP and S(+)-KP in most of the evaluated markers, showing compound-, concentration- and time-specific effect patterns which suggest a potential stereo-selective toxicity of these drugs.

Beneficial effects of Camellia Oil (Camellia oleifera Abel.) on ketoprofen-induced gastrointestinal mucosal damage through upregulation of HO-1 and VEGF

Nonsteroidal anti-inflammatory drugs, such as ketoprofen, are generally used to treat pain and inflammation and as pyretic agents in clinical medicine. However, the usage of these drugs may lead to oxidative injury to the gastrointestinal mucosa. Camellia oil ( Camellia oleifera Abel.) is commonly used in Taiwan and China as cooking oil. Traditional remedies containing this oil exert beneficial health effects on the bowel, stomach, liver, and lungs. However, the effects of camellia oil on ketoprofen-induced oxidative gastrointestinal mucosal lesions remain unknown. The objective of this study was to evaluate the effect of camellia oil on ketoprofen-induced acute gastrointestinal ulcers. The results showed that treatment of Int-407 cells with camellia oil (50-75 μg/mL) not only increased the levels of heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), and superoxide dismutase (SOD) mRNA expression but also increased vascular endothelial growth factor (VEGF) and prostaglandin E2 (PGE2) protein secretion, which served as a mucosal barrier against gastrointestinal oxidative injury. Moreover, Sprague-Dawley (SD) rats treated with camellia oil (2 mL/kg/day) prior to the administration of ketoprofen (50 mg/kg/day) successfully inhibited COX-2 protein expression, inhibited the production of interleukin-6 (IL-6) and nitrite oxide (NO), reversed the impairment of the antioxidant system, and decreased oxidative damage in the gastrointestinal mucosa. More importantly, pretreatment of SD rats with camellia oil strongly inhibited gastrointestinal mucosal injury induced by ketoprofen, which was proved by the histopathological staining of gastrointestinal tissues. Our data suggest that camellia oil exerts potent antiulcer effects against oxidative damage in the stomach and intestine induced by ketoprofen.

Wireless capsule endoscopy in enteropathy induced by nonsteroidal anti-inflammatory drugs in pigs

AIM

The aim of this study is to evaluate the diagnostic yield of capsule endoscopy in nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy in pigs.

MATERIALS AND METHODS

Indomethacin (400 mg/day) was administrated orally for 10 days to eight female pigs weighing 36.3+/-2.4 kg. Afterwards, capsule endoscopy was performed, using the EndoCapsule system (Olympus Optical Co., Tokyo, Japan). The following morning, pharmacological euthanasia and immediate autopsy were performed.

RESULTS

Small bowel injury compatible with NSAID-induced enteropathy was observed in 7/8 animals. The most common lesions were red spots and erosions. Ulcers and small intestinal bleeding were identified sporadically. Sensitivity and specificity of capsule endoscopy were 83.3% and 95.8%, respectively.

CONCLUSION

Our results indicate that wireless capsule endoscopy is a highly accurate noninvasive method for evaluation of experimental NSAID-induced enteropathy.

Encapsulation of ketoprofen and ketoprofen lysinate by prilling for controlled drug release

In this paper, ketoprofen and ketoprofen lysinate were used as model drugs in order to investigate release profiles of poorly soluble and very soluble drug from sodium alginate beads manufactured by prilling. The effect of polymer concentration, viscosity, and drug/polymer ratio on bead micromeritics and drug release rate was studied. Ketoprofen and ketoprofen lysinate loaded alginate beads were obtained in a very narrow dimensional range when the Cross model was used to set prilling operative conditions. Size distribution of alginate beads in the hydrated state was strongly dependent on viscosity of drug/polymer solutions and frequency of the vibration. The release kinetics of the drugs showed that drug release rate was related with alginate concentration and solubility of the drug. Alginate solutions with concentration higher than 0.50% (w/w) were suitable to prepare ketoprofen gastro-resistant formulation, while for ketoprofen lysinate alginate, concentration should be increased to 1.50% (w/w) in order to retain the drug in gastric environment. Differential scanning calorimetry thermograms and Fourier transform infrared analyses of drug-loaded alginate beads indicated complex chemical interactions between carboxyl groups of the drug and polymer matrix in drug-loaded beads that contribute to the differences in release profile between ketoprofen and ketoprofen lysinate. Total release of the drugs in intestinal medium was dependent on the solubility of the drug and was achieved between 4 and 6 h.

Stereoconfiguration of antiallergic and immunologic drugs

OBJECTIVE

To review the concept of chirality and its current role in the pharmacology of antiallergic, antiasthmatic, and immunologic agents.

DATA SOURCES

Ovid MEDLINE and PubMed databases from 1950 to the present time were searched.

STUDY SELECTION

Articles that described the pharmacology of chiral antiallergic, antiasthmatic, and immunologic medications were used for this review.

RESULTS

Stereoselectivity affects the pharmacologic profiles of medications in different ways from class to class and within the classes. This summary illustrates that enantiomers differ not only in potency in receptor binding and physiologic effects but also in pharmacokinetic parameters such as volume of distribution, plasma protein binding, metabolism, and clearance. Different enantiomers may produce unrelated pharmacologic effects as well. This review summarizes the variety of possible effects that different stereoisomers may produce and further underlines the importance of the purification and in-depth analysis of chiral compounds.

CONCLUSION

Chirality plays an important role in pharmacokinetics and pharmacodynamics of various pharmaceutical agents. The importance of stereoisomeric purity in the pharmacologic industry has increased during the past decade as demonstrated by the increased number of studies that examined the in vivo and in vitro effects produced by changes in stereoconfiguration of pharmaceutical agents. This review highlights such effects in certain frequently used medications used in the treatment of asthma and various allergic and immunologic disorders.

Nephrotoxicity induced by the R- and S-enantiomers of N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS) and their sulfate conjugates in male Fischer 344 rats

The agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) induces nephrotoxicity characterized as polyuric renal failure and mediated via metabolites arising from oxidation of the succinimide ring. Recent findings have suggested that the stereochemical nature of NDPS metabolites may be an important factor in NDPS metabolite-induced nephrotoxicity. The purpose of the present study was to determine the role of stereochemistry in the in vivo nephrotoxicity induced by R-(+)- and S-(-)-N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (R- and S-NDHS) and the in vitro nephrotoxicity induced by their enantiomeric sulfate conjugates, R-(-)- and S-(+)-N-(3,5-dichlorophenyl)-2-hydroxysuccinimide-O-sulfate (R- and S-NSC). Male Fischer 344 rats (four rats/group) were administered intraperitoneally (i.p.) an enantiomer of NDHS (0.05, 0.1 or 0.2 mmol/kg) or vehicle, and renal function monitored for 48 h. R-NDHS (0.1 or 0.2 mmol/kg) had little effect on renal function. In contrast, S-NDHS (0.1 mmol/kg) induced marked nephrotoxicity. The nephrotoxic potential of R- and S-NSC (0.5, 0.75 or 1.0mM) was determined using freshly isolated rat renal cortical cells (IRCC, 3-4 x 10(6)cells/ml). Cytotoxicity was determined by measuring the release of lactate dehydrogenase (LDH) at the end of a 1h incubation period. The LDH release observed in these studies was similar between R- and S-NSC. These results indicate that stereochemistry is an important factor for NDPS metabolite nephrotoxicity and that the role of stereochemistry, at least for NSC, occurs at extra-renal sites.

Safety of reduced-dosage ketoprofen for long-term oral administration in healthy dogs

OBJECTIVE

To evaluate the safety of reduced-dosage ketoprofen (RDKET) for long-term oral administration in healthy dogs.

ANIMALS

14 healthy Beagles.

PROCEDURES

Racemic ketoprofen (0.25 mg/kg, PO) and gelatin capsules, as a drug-free placebo, were each administered to 7 dogs for 30 days. Dogs were periodically monitored via physical examination, blood analyses, endoscopic examinations, fecal occult blood tests (tetramethylbenzidine and guaiac methods), renal function tests (effective renal plasma flow and glomerular filtration rate), urinalyses, urinary enzyme indices (N-acetyl-beta-D-glucosaminidase and gamma-glutamyl-transferase), and hemostatic function tests (buccal mucosa bleeding time, cuticle bleeding time, prothrombin time, activated partial thromboplastin time, and fibrinogen concentration).

RESULTS

Pyloric antrum lesion grade was significantly higher in the RDKET group on day 28, compared with the pretreatment and control group grades. Fecal occult blood grade measured by use of the tetramethylbenzidine method was significantly higher in the RDKET group on day 30, compared with the pretreatment grade. No other significant differences were detected between treatment groups.

CONCLUSIONS AND CLINICAL RELEVANCE

RDKET induced mild to moderate gastric mucosal injuries especially in the pyloric antrum in healthy Beagles, whereas no adverse effects were observed in renal function or hemostasis. Fecal occult blood tests may be useful as screening tests for adverse gastrointestinal effects induced by RDKET in dogs.

Gastric toxicity of racemic ketoprofen and its enantiomers in rat: oxygen radical generation and COX-expression

OBJECTIVE AND DESIGN

The gastric toxicity of racemic-ketoprofen and its enantiomers (S(+)- and R(-)-ketoprofen), oxygen free radical generation and neutrophil infiltration in response to damage were evaluated in rats. Changes in prostaglandin synthesis, cyclooxygenase expression and glutathione metabolism were also studied.

MATERIALS AND METHODS

Studies were performed in Wistar rats. Drugs were given by oral administration: racemic-ketoprofen (100, 50 and 25 mg/kg body weight); S(+) and R(-)-ketoprofen (50, 25 and 12.5 mg/kg body weight). Determinations were made of gastric mucosal injury, lipid peroxidation, xanthine oxidase, myeloperoxidase and superoxide dismutase activities, glutathione levels, glutathione peroxidase and glutathione reductase activities, gastric prostaglandin synthesis (PGE2 levels) and COX-expression.

RESULTS

Racemic-ketoprofen dose-dependently exhibited the highest toxicity. In contrast, S(+)-ketoprofen at half the dose of the racemic compound proved to be less ulcerogenic. R(-)-ketoprofen was also less ulcerogenic, but when administered as the racemate exacerbated gastric ulceration caused by S(+)-ketoprofen. Drug administration produced significant increases in lipid peroxidation levels and xanthine-oxidase and a decrease in superoxide dismutase activity. Nevertheless the racemate induced the highest disturbances in oxidative metabolism. No changes in myeloperoxidase values and glutathione metabolism were found. Cyclooxygenase-1 immunoreactivity was observed and did not differ from that in control rats. Cyclooxygenase-2 could also be expressed after treatments.

CONCLUSIONS

R(-)-ketoprofen and S(+)-ketoprofen have a comparable gastric toxicity and they both have a better gastric toxicity profile as compared to the racemate. In addition to inhibition of prostaglandin synthesis, damage resulted in an increase of cyclooxygenase-2 protein expression. Oxygen radicals, including superoxide anions, could also be implicated.

Role of stereochemistry in N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA) nephrotoxicity

The nephrotoxicity induced by the agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) is mediated through oxidative metabolites of NDPS. Oxidation of the succinimide ring in NDPS yields the nephrotoxic metabolites N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS) and its hydrolysis product N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA). The oxidation of NDPS on the succinimide ring also introduces an asymmetric carbon atom into these NDPS metabolites, so that R- and S- enantiomers of NDHS and 2-NDHSA are possible. The purpose of this study was to begin to explore the importance of the stereochemical orientation at the asymmetric carbon atom for the nephrotoxicity induced by NDPS metabolites. Male Fischer 344 rats were administered a single intraperitoneal (ip) injection of R-(+)- or S-(-)-2-NDHSA (0.05, 0.1 or 2.0 mmol/kg) or vehicle, and renal function was monitored for 48 h. R-2-NDHSA (0.1 mmol/kg) administration had little effect on renal function. R-2-NDHSA (0.2 mmol/kg) treatment induced mild diuresis on day 1, increased proteinuria, and a small increase in blood urea nitrogen (BUN) concentration, but no change in kidney weight or glucosuria. S-2-NDHSA (0.1 mmol/kg) induced marked nephrotoxicity as evidenced by diuresis on both post-treatment days, increased proteinuria, glucosuria, and increased kidney weight and BUN concentration. No evidence of hepatotoxicity was obtained in any treated group. Thus, the S-isomer of 2-NDHSA is a more potent nephrotoxicant than the R-isomer, and stereochemistry may play a role in NDPS metabolite-induced nephrotoxicity.