Indomethacin-induced renal damage: role of oxygen free radicals

Nifuroxazide attenuates indomethacin-induced renal injury by upregulating Nrf2/HO-1 and cytoglobin and suppressing NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals

Indomethacin (INDO) is an NSAID with remarkable efficacy and widespread utilization for alleviating pain. Nevertheless, renal function impairment is an adverse reaction linked to INDO usage. Nifuroxazide (NFX), an oral nitrofuran antibiotic, is frequently employed as an intestinal anti-infective agent. Our study aimed to investigate the renoprotective effects of NFX against INDO-induced nephrotoxicity and explore the protection mechanisms. Four groups of rats were allocated to (I) the normal control, (II) the NFX-treated (50 mg/kg), (III) INDO control (20 mg/kg), and (IV) NFX + INDO. NFX attenuates renal impairment in INDO-induced renal injury, proved by decreasing serum levels of urea, creatinine, uric acid, and NGAL while the albumin was elevated. NFX mitigates renal oxidative stress by decreasing MDA levels and restoring the antioxidants' GSH and SOD levels mediated by upregulating Nrf2, HO-1, and cytoglobin pathways. NFX mitigated renal inflammation and effectively decreased MPO, IL-1β, and TNF-α levels in the rat's kidney mediated by significant downregulation of NADPH-oxidase and NF-κB expression and suppression of JAK-1 and STAT3 phosphorylation. NFX mitigates renal apoptosis by decreasing the expression of cleaved caspase-3 expression. In conclusion, NFX treatment prevents INDO nephrotoxicity by regulating Nrf2/HO-1, cytoglobin, NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals.

Induction of mitochondrial toxicity by non-steroidal anti-inflammatory drugs (NSAIDs): The ultimate trade-off governing the therapeutic merits and demerits of these wonder drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are most extensively used over-the-counter FDA-approved analgesic medicines for treating inflammation, musculoskeletal pain, arthritis, pyrexia and menstrual cramps. Moreover, aspirin is widely used against cardiovascular complications. Owing to their non-addictive nature, NSAIDs are also commissioned as safer opioid-sparing alternatives in acute trauma and post-surgical treatments. In fact, therapeutic spectrum of NSAIDs is expanding. These "wonder-drugs" are now repurposed against lung diseases, diabetes, neurodegenerative disorders, fungal infections and most notably cancer, due to their efficacy against chemoresistance, radio-resistance and cancer stem cells. However, prolonged NSAID treatment accompany several adverse effects. Mechanistically, apart from cyclooxygenase inhibition, NSAIDs directly target mitochondria to induce cell death. Interestingly, there are also incidences of dose-dependent effects where NSAIDs are found to improve mitochondrial health thereby suggesting plausible mitohormesis. While mitochondria-targeted effects of NSAIDs are discretely studied, a comprehensive account emphasizing the multiple dimensions in which NSAIDs affect mitochondrial structure-function integrity, leading to cell death, is lacking. This review discusses the current understanding of NSAID-mitochondria interactions in the pathophysiological background. This is essential for assessing the risk-benefit trade-offs of NSAIDs for judiciously strategizing NSAID-based approaches to manage pain and inflammation as well as formulating effective anti-cancer strategies. We also discuss recent developments constituting selective mitochondria-targeted NSAIDs including theranostics, mitocans, chimeric small molecules, prodrugs and nanomedicines that rationally optimize safer application of NSAIDs. Thus, we present a comprehensive understanding of therapeutic merits and demerits of NSAIDs with mitochondria at its cross roads. This would help in NSAID-based disease management research and drug development.

Fragment merging approach for the design of thiazole/thiazolidine clubbed pyrazoline derivatives as anti-inflammatory agents: Synthesis, biopharmacological evaluation and molecular modeling studies

Fragment merging approach was applied for the design of thiazole/thiazolidinone clubbed pyrazoline derivatives 5a-e, 6a-c, 7 and 10a-d as dual COX-2 and 5-LOX inhibitors. Compounds 5a, 6a, and 6b were the most potent and COX-2 selective inhibitors (IC50= 0.03-0.06 μM, SI = 282.7-472.9) with high activity against 5-LOX (IC50 = 4.36-4.86 μM), while compounds 5b and 10a were active and selective 5-LOX inhibitors with IC50 = 2.43 and 1.58 μM, respectively. In vivo assay and histopathological examination for most active candidate 6a revealed significant decrease in inflammation with higher safety profile in comparison to standard drugs. Compound 6a exhibited the same orientation and binding interactions as the reference COX-2 and 5-LOX inhibitors (celecoxib and quercetin, respectively). Consequently, compound 6a has been identified as a potential lead for further optimization and the development of safe and effective anti-inflammatory drugs.

Mechanochemical prepared ibuprofen-Polygonatum sibiricum polysaccharide drug delivery system for enhanced bioactivity with reduced renal injury induced by NSAIDs

Ibuprofen (IBU) was a widely used NSAID (a type of nonsteroidal anti-inflammatory drug) worldwide, and many drug deliveries had been reported to enhance bioavailability. However, higher bioavailability would increase the danger of renal injury caused by oxidative stress. This study prepared IBU-Polygonatum sibiricum polysaccharide (IBU-PSP) drug delivery system via mechanochemical method. Due to drug delivery and renal protection effect of Polygonatum sibiricum polysaccharide (PSP), the solubility of IBU-PSP was increased 8.22 times, and the bioavailability was increased 2.52 times compared with IBU, carrageenin-induced rat paw edema test also increased. Meanwhile, short-term and long-term renal injuries induced by IBU were notable decreases. In conclusion, IBU-PSP was a multifunctional drug delivery system with superior anti-inflammatory and renal protection effects. It will benefit from developing high-efficiency NADIs preparations with safer clinical applications while providing an efficient and energy-saving technology for polysaccharide drug delivery.

Non-steroidal anti-inflammatory drugs (NSAIDs) and organ damage: A current perspective

Owing to the efficacy in reducing pain and inflammation, non-steroidal anti-inflammatory drugs (NSAIDs) are amongst the most popularly used medicines confirming their position in the WHO's Model List of Essential Medicines. With escalating musculoskeletal complications, as evident from 2016 Global Burden of Disease data, NSAID usage is evidently unavoidable. Apart from analgesic, anti-inflammatory and antipyretic efficacies, NSAIDs are further documented to offer protection against diverse critical disorders including cancer and heart attacks. However, data from multiple placebo-controlled trials and meta-analyses studies alarmingly signify the adverse effects of NSAIDs in gastrointestinal, cardiovascular, hepatic, renal, cerebral and pulmonary complications. Although extensive research has elucidated the mechanisms underlying the clinical hazards of NSAIDs, no review has extensively collated the outcomes on various multiorgan toxicities of these drugs together. In this regard, the present review provides a comprehensive insight of the existing knowledge and recent developments on NSAID-induced organ damage. It precisely encompasses the current understanding of structure, classification and mode of action of NSAIDs while reiterating on the emerging instances of NSAID drug repurposing along with pharmacophore modification aimed at safer usage of NSAIDs where toxic effects are tamed without compromising the clinical benefits. The review does not intend to vilify these 'wonder drugs'; rather provides a careful understanding of their side-effects which would be beneficial in evaluating the risk-benefit threshold while rationally using NSAIDs at safer dose and duration.

A Method for the Evaluation of Site-Specific Nephrotoxic Injury in the Intact Rat Kidney

In a previously published report we detailed an in situ method to quantify cell death in the renal cortex by perfusing the cell membrane impermeable fluorochrome, ethidium homodimer in situ. The objective of the present study was to use this in situ viability assay to examine cell death following the administration of nephrotoxic drugs known to produce cell death and/or injury in specific segments of the nephron. Male Sprague/Dawley rats were treated with the following nephrotoxicants: Gentamicin, amphotericin-B, and indomethacin. Results of the in situ viability assay indicated that gentamicin and amphotericin-B treatment caused cell death localized in the kidney cortex and medulla, respectively. The urinary biomarker kidney injury molecule-1 (Kim-1) showed significant increases in both gentamicin (20 fold increase) and amphotericin-B-treated (9.2 fold increase) animals. Urinary alpha glutathione-S-transferase (GST) showed significant increases for gentamicin (6.2 fold increase) only and mu GST for amphotericin-B-treated (19.1 fold increase) animals only. These results show that this in situ viability assay provides a sensitive method to identify cell death in different regions of the kidney. Furthermore, urinary alpha GST and mu GST are specific for proximal and distal tubule injury, respectively; urinary Kim-1 demonstrated greater sensitivity to both proximal and distal tubule injury.

Comparative effect of indomethacin (IndoM) on the enzymes of carbohydrate metabolism, brush border membrane and oxidative stress in the kidney, small intestine and liver of rats

Indomethacin (IndoM) has prominent anti-inflammatory and analgesic-antipyretic properties. However, high incidence and severity of side-effects on the structure and functions of the kidney, liver and intestine limits its clinical use. The present study tested the hypothesis that IndoM causes multi-organ toxicity by inducing oxidative stress that alters the structure of various cellular membranes, metabolism and hence functions. The effect of IndoM was determined on the enzymes of carbohydrate metabolism, brush border membrane (BBM) and oxidative stress in the rat kideny, liver and intestine to understand the mechanism of IndoM induced toxicity. Adult male Wister rats were given IndoM (20 mg/kg) intra-peritoneally in sodium bicarbonate twice a day for 3 d. The body weights of the rats were recorded before and after experimental procedure. IndoM administration significantly increased blood urea nitrogen, serum creatinine, cholesterol and alkaline phosphatase but inorganic phosphate indicating IndoM induced renal, hepatic and intestinal toxicity. Activity of lactate dehydrogenase along with glucose-6- and fructose-1, 6-bis phosphatase, glucose-6-phosphate dehydrogenase and NADP-malic enzyme increased but malate dehydrogenase decreased in all tissues. Lipid peroxidation (LPO) significantly increased whereas the antioxidant enzymes decreased in all rat tissues studied. The results indicate that IndoM administration caused severe damage to kidney, liver and intestine by icreasing LPO, suppressing antioxidant enzymes and inhibiting oxidative metablolism. The energy dependence was shifted to anaerobic glycolysis due to mitochondrial damage supported by increased gluconeogenesis to provide more glucose to meet energy requirements.

The efficacy of oleuropein against non-steroidal anti-inflammatory drug induced toxicity in rat kidney

Indomethacin is generally used in clinical therapeutics as a non-steroidal anti-inflammatory drug. However, its use has been limited due to the gastrointestinal and renal toxic effects of this drug. These toxic effects were associated with not only the inhibition of prostaglandin synthesis but also drug-elevated oxidative stress. To ameliorate these toxicities, natural antioxidants can be used as an alternative and/or combination therapies. Therefore, the current study was conducted to assess the renoprotective effects of oleuropein against indomethacin-induced renal damages. Male Sprague-Dawley rats were pretreated with oleuropein (75, 150, and 300 mg/kg), and then treated with indomethacin (25 mg/kg). To evaluate kidney function, serum blood urea nitrogen, uric acid, and creatinine were measured. In addition, prostaglandin E₂ , tumor necrosis factor-alpha, endothelial nitric oxide synthase, caspase-3, oxidant/antioxidant status, and 8-Oxo-2'-deoxyguanosine levels were determined for the antioxidative and anti-inflammatory effects of oleuropein. Tissue sections were also histopathologically assessed. The biochemical and histopathological analysis proved the toxic effects of indomethacin on kidney. However, the pretreatment with oleuropein (300 mg/kg) protects kidney from indomethacin-induced damages. Our study proved that prior administration of oleuropein has renoprotective activity against indomethacin-associated toxicities.

Antibiotics Protect against Septic Shock in Mice Administered β-Glucan and Indomethacin

We have developed an animal model of sepsis in mice by repeatedly administering beta-glucan, a biological response modifier, and indomethacin (IND), a nonsteroidal anti-inflammatory drug. The combination of these drugs induced bacteremia by translocation of the enterobacterial flora, resulting in increasing the number of activated leukocytes, and inducing hyper cytokinemia. In the present study, we examined the effect of antibiotics on beta-glucan and IND-induced septic shock. Treatment with antibiotics inhibited microbial translocation, inhibited contraction of the colon, reduced lipopolysaccharides (LPS)-elicited production of TNF-alpha and IL-6, and finally prolonged survival. However, the efficacy of antibiotics treatment was limited in mice administered IND orally. These findings strongly suggested that the antibiotics controlled the gut-associated action of IND and reduced various symptoms accompanying sepsis.

Interaction of nonsteroidal anti-inflammatory drugs with membranes: in vitro assessment and relevance for their biological actions

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used drugs in the world due to their anti-inflammatory, analgesic and antipyretic properties. Nevertheless, the consumption of these drugs is still associated with the occurrence of a wide spectrum of adverse effects. Regarding the major role of membranes in cellular events, the hypothesis that the biological actions of NSAIDs may be related to their effect at the membrane level has triggered the in vitro assessment of NSAIDs-membrane interactions. The use of membrane mimetic models, cell cultures, a wide range of experimental techniques and molecular dynamics simulations has been providing significant information about drugs partition and location within membranes and also about their effect on diverse membrane properties. These studies have indeed been providing evidences that the effect of NSAIDs at membrane level may be an additional mechanism of action and toxicity of NSAIDs. In fact, the pharmacokinetic properties of NSAIDs are closely related to the ability of these drugs to interact and overcome biological membranes. Moreover, the therapeutic actions of NSAIDs may also result from the indirect inhibition of cyclooxygenase due to the disturbing effect of NSAIDs on membrane properties. Furthermore, increasing evidences suggest that the disordering effects of these drugs on membranes may be in the basis of the NSAIDs-induced toxicity in diverse organ systems. Overall, the study of NSAIDs-membrane interactions has proved to be not only important for the better understanding of their pharmacological actions, but also for the rational development of new approaches to overcome NSAIDs adverse effects.

Nonsteroidal Anti-Inflammatory Drugs and the Kidney

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the isoenzymes COX-1 and COX-2 of cyclooxygenase (COX). Renal side effects (e.g., kidney function, fluid and urinary electrolyte excretion) vary with the extent of COX-2-COX-1 selectivity and the administered dose of these compounds. While young healthy subjects will rarely experience adverse renal effects with the use of NSAIDs, elderly patients and those with co-morbibity (e.g., congestive heart failure, liver cirrhosis or chronic kidney disease) and drug combinations (e.g., renin-angiotensin blockers, diuretics plus NSAIDs) may develop acute renal failure. This review summarizes our present knowledge how traditional NSAIDs and selective COX-2 inhibitors may affect the kidney under various experimental and clinical conditions, and how these drugs may influence renal inflammation, water transport, sodium and potassium balance and how renal dysfunction or hypertension may result.

The antioxidant role of oral administration of garlic oil on renal ischemia-reperfusion injury

AIM

In this study we examined the effect of oral application of garlic form [garlic oil (GO)] on rats after renal ischemia-reperfusion (I/R) injury.

MATERIALS AND METHODS

Forty male Wistar albino rats were divided into four groups: control, sham-operated, I/R, and I/R+GO. GO was diluted in water and administered by oral intubation three times each week for 6 weeks. All rats except sham-operated underwent 45 min of bilateral renal ischemia followed by 6 hr of reperfusion. Blood samples and kidney tissues were harvested from the rats, and then rats were killed. Serum urea, creatinine, and cystatin C levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidant status (TOS), oxidative stress index (OSI), myeloperoxidase (MPO), nitrite oxide (NO), and protein carbonyl (PC) levels in kidney tissue and blood were measured. In addition, kidney tissue histopathology was evaluated.

RESULTS

The serum urea, creatinine, and cystatin C levels were significantly higher in I/R group compared to I/R+GO group (p<0.01). The serum and tissue antioxidant markers (TAC, CAT) were significantly lower in I/R group than I/R+GO group (p<0.01). The serum oxidant markers (TOS, MPO, NO, and PC) were significantly higher in I/R group than I/R+GO group (p<0.01). Also oral application of GO was effective in decreasing of tubular necrosis score.

CONCLUSION

Based on the present data, we conclude that increased antioxidants and decreased oxidants modulated by oral application of GO attenuated the renal I/R injury.

Protective effects of Nigella sativa against ischemia-reperfusion injury of kidneys

BACKGROUND

Ischemia-reperfusion, commonly seen in the fields of trauma surgery and renal transplantation, is a major cause of acute kidney injury and is associated with significant morbidity and mortality. The protective effects of Nigella sativa against ischemia-perfusion damage to various organs have been previously documented. However, its protective effects on kidney tissue against ischemia-reperfusion injury are unclear. In this study, we aimed to examine the effect of Nigella sativa in modulating inflammation and apoptosis after renal I/R injury.

MATERIALS AND METHODS

Thirty male Wistar-albino rats were divided into three groups: sham-operated, ischemia-reperfusion, and ischemia-reperfusion + Nigella sativa. Rats in the third group were given Nigella sativa 6 h prior to ischemia-reperfusion and at the beginning of reperfusion. All rats except those in the sham-operated group underwent 45 min of bilateral renal ischemia followed by 45 min of reperfusion. Blood samples and liver tissues were harvested from the rats, and then rats were sacrificed. Serum urea and creatinine levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidant status (TOS), oxidative stress index (OSI), and myeloperoxidase (MPO) in kidney tissue and blood were measured. Kidney tissue histopathology was also evaluated. Results. Nigella sativa was effective in reducing serum urea and creatinine levels as well as decreasing the tubular necrosis score. Nigella sativa treatment significantly reduced OSI and TOS levels and increased TAC levels in both kidney tissue and blood.

CONCLUSION

The observed differences seem to demonstrate the protective effect of Nigella sativa against renal I/R injury in rat kidneys.

Oxidative Stress Mediated Idiosyncratic Drug Toxicity

The following describes a novel screening method for "new chemical entities" (NCEs), suitable for ADMET studies, that measures ability to form prooxidant radicals on metabolism and their ability to induce oxidative stress in intact cells. The accelerated molecular cytotoxic mechanism screening (ACMS) techniques used with isolated rat hepatocytes showed that cytotoxicity is usually initiated as a result of macromolecular covalent binding or macromolecular oxidative stress. While P450 is likely responsible for drug metabolic activation in the liver, intestine, lung, and in other nonhepatic tissues, where P450 levels are low, peroxidases including prostaglandin synthetase peroxidase can catalyze xenobiotic one-electron oxidation to form prooxidant free radicals that may cause toxicity or carcinogenesis. Inflammation markedly activates H2O2, generating NADPH oxidase and peroxidase of certain immune cells when they infiltrate tissues including the liver. Myeloperoxidase and NADPH oxidase in the Kupffer cells (resident macrophages of the liver) also become activated during inflammation. The addition of noncytotoxic concentrations of peroxidase/H2O2 to the hepatocyte incubate markedly increased drug cytotoxicity and prooxidant radical formation as shown by glutathione or lipid oxidation. Many drugs that have hepato- or gastrointestinal (GI) toxicity problems or were withdrawn from the market for safety problems, e.g., troglitazone, tolcapone, mefenamic acid, diclofenac, and phenylbutazone, were markedly more toxic and prooxidant in this inflammation model system, whereas other drugs, e.g., entacapone, were not toxic in this inflammation model. Some of the idiosyncratic hepatotoxicity responsible for recent drug withdrawals may therefore result from commonplace sporadic inflammatory episodes during drug therapy.

Therapeutic Approach by a Novel Designed Anti-Inflammatory Drug, M2000, in Experimental Immune Complex Glomerulonephritis

The therapeutic efficacy of novel designed nonsteroidal anti-inflammatory drug, M2000 (beta- D- mannuronic acid) on experimental immune complex glomerulonephritis was evaluated. Bovine serum albumin (BSA) nephritis was induced in rats by a subcutaneous immunization and daily intravenous administration of BSA. M2000 solution (30 mg/kg) was administered intraperitoneally at regular 48-hr intervals for 4 weeks. Onset of treatment was day 56. Urinary protein was measured weekly and serum anti-BSA antibody was assessed by ELISA method at different intervals. Animals were killed on day 84 and blood samples and kidney specimens were obtained. Serum (creatinine, blood urea nitrogen, cholesterol, and triglyceride) and urine (protein, urea, and creatinine) determinants were measured at the time of sacrifice. Kidney specimens were processed for light and immunofluorescent microscopic examination. The fibrosarcoma cell line was used for assaying tolerability and matrix metalloproteinase type 2 (MMP-2) activity. MMP-2 activity was assessed using zymography. Our data showed that M2000 therapy could significantly reduce the urinary protein excretion in treated rats versus non-treated controls. Anti-BSA antibody titer was lower in treated rats than in controls at the 12th experimental week. Polymorphonuclear neutrophil leukocytes infiltration and glomerular immune complex deposition were less intense in treated rats than in controls. Cytotoxicity analysis of M2000 showed a much higher tolerability compared with other tested drugs (diclofenac, piroxicam and dexamethasone). The inhibitory effect of M2000 in MMP-2 activity was significantly greater than that of dexsamethasone and of piroxicam at a concentration of 200 microg/ml. Moreover, the toxicological study revealed that M2000 had no influence on serum (BUN, creatinine, triglyceride and cholesterol) determinants, urinary protein excretion and glomerular histology in healthy group receiving drug.

CONCLUSIONS

These findings suggest that treatment with M2000 can reduce proteinuria, diminish antibody production, and suppress the progression of disease in a rat model of immune complex glomerulonephritis.

NMR-based urine analysis in rats: prediction of proximal tubule kidney toxicity and phospholipidosis

INTRODUCTION

The aim of safety pharmacology is early detection of compound-induced side-effects. NMR-based urine analysis followed by multivariate data analysis (metabonomics) identifies efficiently differences between toxic and non-toxic compounds; but in most cases multiple administrations of the test compound are necessary. We tested the feasibility of detecting proximal tubule kidney toxicity and phospholipidosis with metabonomics techniques after single compound administration as an early safety pharmacology approach.

METHODS

Rats were treated orally, intravenously, inhalatively or intraperitoneally with different test compounds. Urine was collected at 0-8 h and 8-24 h after compound administration, and (1)H NMR-patterns were recorded from the samples. Variation of post-processing and feature extraction methods led to different views on the data. Support Vector Machines were trained on these different data sets and then aggregated as experts in an Ensemble. Finally, validity was monitored with a cross-validation study using a training, validation, and test data set.

RESULTS

Proximal tubule kidney toxicity could be predicted with reasonable total classification accuracy (85%), specificity (88%) and sensitivity (78%). In comparison to alternative histological studies, results were obtained quicker, compound need was reduced, and very importantly fewer animals were needed. In contrast, the induction of phospholipidosis by the test compounds could not be predicted using NMR-based urine analysis or the previously published biomarker PAG.

DISCUSSION

NMR-based urine analysis was shown to effectively predict proximal tubule kidney toxicity after single compound administration in rats. Thus, this experimental design allows early detection of toxicity risks with relatively low amounts of compound in a reasonably short period of time.

Renal deterioration caused by carcinogens as a consequence of free radical mediated tissue damage: a review of the protective action of melatonin

This brief review summarizes some of the publications that document the preventive role of melatonin in kidney damage caused by carcinogens such as 2-nitropropane, arsenic, carbon tetrachloride, nitrilotriacetic acid and potassium bromate. Numerous chemicals generate excessive free radicals that eventually induce renal worsening. Melatonin partially or totally prevents free radical mediated tissue damages induced by many carcinogens. Protective actions of melatonin against the harmful effects of carcinogens are believed to stem from its direct free radical scavenging and indirect antioxidant activities. Dietary or pharmacologically given melatonin may attenuate the oxidative stress, thereby mitigating the subsequent renal damage.

Production of M2000 (β-d-mannuronic acid) and its therapeutic effect on experimental nephritis

The present research introduces the method of Production of M2000 (β-d-mannuronic acid) and its therapeutic effect on experimental model of nephritis. M2000 was produced using enzymatic and chemical procedure on prepared alginate from Pseudomonas fluorescens. The experimental glomerulonephritis was induced in rats by a subcutaneous immunization and daily intravenous administration of bovine serum albumin (BSA). M2000 solution (30mg/kg) was administered intraperitoneally at regular 48-h intervals for 4 weeks. Onset of treatment was day 56. Urinary protein was measured weekly and serum anti-BSA antibody was assessed by ELISA method at different intervals. Animals were killed on day 84 and blood samples and kidney specimens were obtained. Serum (creatinine, BUN, cholesterol, and triglyceride) and urine (protein, urea, and creatinine) determinants were measured at the time of sacrifice. Kidney specimens were processed for light and immunofluorescent microscopic examination. The fibrosarcoma cell line was used for assaying tolerability and matrix metalloproteinase type 2 (MMP-2) activity. MMP-2 activity was assessed using zymography. Our data showed that M2000 therapy could significantly reduce the urinary protein excretion in treated rats versus non-treated controls. Anti-BSA antibody titer was lower in treated rats than in controls at the 12th experimental week. PMN infiltration and glomerular immune complex deposition was less intense in treated rats than in controls. Cytotoxicity analysis of M2000 showed a much higher tolerability compared with other tested drugs (diclofenac, piroxicam and dexamethasone). The inhibitory effect of M2000 in MMP-2 activity was significantly greater than that of dexsamethasone and of piroxicam at a concentration of 200μg/ml. Moreover, the toxicological study revealed that M2000 had no influence on serum (BUN, creatinine, triglyceride and cholesterol) determinants, urinary protein excretion and glomerular histology in healthy group receiving drug.

CONCLUSIONS

In this research, for the first time we introduced the procedure of production of M2000 (β-d-mannuronic acid) and our data suggest that treatment with M2000, as a novel anti-inflammatory drug can reduce proteinuria, diminish antibody production and suppress the progression of disease in experimental model of glomerulonephritis.

Urinary Metabolites of Oxidative Stress and Nitric Oxide in Preterm and Term Infants

BACKGROUND

Many neonatal diseases have been associated with oxidative stress and altered nitric oxide status.

OBJECTIVE

To determine the effects of clinical interventions on the levels of urinary peroxides, a marker of oxidative stress, and urinary nitrate/nitrites, indices of nitric oxide production and metabolism, in the first 72 h of life in premature infants.

METHODS

A single, spot urine sample was collected from 82 premature and 20 healthy term infants within the first 72 h of life. The peroxide levels were quantified using a fluorometric method, and nitrate/nitrite levels were quantified by chemiluminescence.

RESULTS

Premature infants had a median peroxide level of 10.0 micromol/mmol creatinine (Cr) (interquartile range 4.8-20.0 micromol/mmol Cr). These values were significantly higher than term infants (median 5.0 micromol/mmol Cr, interquartile range 2.7-10.0 micromol/mmol Cr). Urinary nitrate/nitrite levels were not significantly different between preterm (220.5 micromol/mmol Cr, interquartile range 161-287 micromol/mmol Cr) and healthy term infants (244 micromol/mmol Cr, interquartile range 194-316 micromol/mmol Cr). For urinary peroxides, infants on TPN had significantly higher urinary peroxide levels than infants who were not on TPN at the time of urine collection (p = 0.006). Administration of indomethacin was associated with lower levels of urinary nitrate/nitrites (p = 0.0003). Both effects remained significant after controlling for gestational age, degree of respiratory distress and day of urine collection.

CONCLUSION

Monitoring the level of both peroxides and nitrate/nitrite may offer added information about the degree of oxidative stress experienced by a newborn but needs to account for clinical and therapeutic interventions.

Paradoxical rebound platelet activation after painkillers cessation: missing risk for vascular events?

BACKGROUND

Several reliable reports strongly indicate that the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors is associated with an increased risk of cardiovascular events. Considering the key role of platelets in coronary atherosclerosis and the fact that antiplatelet therapy with aspirin (and more recently, clopidogrel) has been associated with reduced vascular mortality, we sought to determine the effect of therapy and withdrawal of NSAIDs and COX-2 inhibitors on platelet activity.

METHODS

Platelet characteristics from 34 aspirin-naive volunteers who were receiving NSAIDs and COX-2 inhibitors were compared with 138 drug-free controls. Platelets were assessed twice at baseline (at least 1 month of NSAIDs and COX-2 inhibitors) and after a 14-day washout. We used adenosine diphosphate-induced conventional aggregometry, the point-of-care Ultegra analyzer (Ultegra Accumetrics, San Diego, Calif), and whole blood flow cytometry.

RESULTS

Platelet activity during therapy with NSAIDs and COX-2 inhibitors was similar and unremarkable between groups. However, there was a highly significant increase of platelet activity as assessed by conventional aggregometry (P=.0003), Ultegra analyzer readings (P=.03), and expression of GPIIb/IIIa (P=.02), P-selectin (P=.03), and platelet endothelial cell adhesion molecule-1 (P=.001) after withdrawal from NSAIDs and COX-2 inhibitors.

CONCLUSIONS

These data suggest that drug cessation, rather than continuous therapy with NSAIDs and COX-2 inhibitors, may be associated with rebound platelet activation, which may predispose one to a higher risk of vascular events. This hypothesis requires intensive testing in crossover randomized studies and may justify more aggressive antiplatelet regimens in patients after discontinuation of therapy with NSAIDs and COX-2 inhibitors.

Renal damage in experimentally-induced cirrhosis in rats: Role of oxygen free radicals

Cirrhosis with ascites is associated with impaired renal function accompanied by sodium and water retention. Although it has been suggested that mediators such as nitric oxide play a role in the development of renal failure in this situation, other mechanisms underlying the process are not well understood. This study examined the role of oxidative stress in mediating renal damage during the development of cirrhosis in order to understand mechanisms involved in the process. It was shown that carbon tetrachloride- or thioacetamide-induced cirrhosis in rats results in oxidative stress in the kidney as seen by increased lipid peroxidation and protein oxidation, accompanied by altered antioxidant status. Cirrhosis was also found to affect renal mitochondrial function, as assessed by measurement of the respiratory control ratio, the swelling of mitochondria, and calcium flux across mitochondrial membranes. Increased lipid peroxidation and changes in lipid composition were evident in the renal brush border membranes, with compromised transport of 14C glucose across these membranes. In conclusion, renal alterations produced as a result of cirrhosis in the rat are possibly mediated by oxidative stress.

Indomethacin induces free radical-mediated changes in renal brush border membranes

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used extensively in clinical medicine. One disadvantage of their use, however, is the occurrence of adverse effects in the kidneys. The side effects produced in this organ have been classically attributed to the inhibitory effect of these drugs on the activity of cyclooxygenase, a key enzyme in prostaglandin synthesis. Our earlier work with indomethacin, a commonly used NSAID, has shown that oxidative stress and mitochondrial dysfunction occur in the kidney in response to the drug. In view of this, this study looked into the effect of indomethacin on brush border membranes (BBM) from the kidney, as these biomembranes are prime targets of oxygen free radicals. Rats, fasted overnight, were dosed with indomethacin (20 mg/kg) by gavage and sacrificed 24 h later. BBM were isolated from the kidneys by polyethylene glycol precipitation. It was found that there was an increase in levels of products of peroxidation and a fall in the level of alpha-tocopherol in the BBM from indomethacin-dosed rats. These BBM also exhibited impaired glucose transport. The lipid composition of the membranes was also found to be altered. Alterations in lipids were associated with up-regulation of phospholipase A2. Pretreatment with L-arginine, a nitric oxide donor, protected against these effects of indomethacin. Thus, this study suggests that indomethacin induces impairment in structure and function of BBM in the kidney, with these effects possibly mediated by free radicals and activation of phospholipases. We postulate that such alterations may be important in the pathogenesis of NSAID-induced nephropathy.

M-2000, as a new anti-inflammatory molecule in treatment of experimental nephrosis

The therapeutic effect of M-2000 (C6H10O7) molecule was tested in Adriamycin-induced nephropathy. To induce experimental nephrosis, Adriamycin was given once by a single intravenous injection (7.5 mg/kg) through the tail vein. Six days after injection of Adriamycin, therapeutic protocol was developed by intraperitoneally (i.p) administration of 30 mg/kg M-2000 solution. Total of i.p. injections were 14, in which five injections were made every day and nine injections were carried out at regular 48-h intervals. Therapeutic protocol was terminated on day 28 and animals were killed on day 43. The treated patient rats showed a significant reduction in proteinuria, BUN, serum creatinine and serum cholesterol, as well as, administration of M-2000 could significantly diminish the serum level of interleukin-6 (IL-6) in treated animals compared to non-treated controls. Moreover, treatment with M-2000 significantly reduced number of glomerular leukocytes, Hypercellularity and hydropic change in capillary network within the renal cortex and decreased tubular casts. These data suggest that M-2000 therapy can ameliorate proteinuria, and suppress the progression of glomerular lesions in experimental model of nephrosis.