Nimesulide interaction with membrane model systems: Are membrane physical effects involved in nimesulide mitochondrial toxicity?

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.

Lipid Nanosystems and Serum Protein as Biomimetic Interfaces: Predicting the Biodistribution of a Caffeic Acid-Based Antioxidant

Purpose

AntiOxCIN₃ is a novel mitochondriotropic antioxidant developed to minimize the effects of oxidative stress on neurodegenerative diseases. Prior to an investment in pre-clinical in vivo studies, it is important to apply in silico and biophysical cell-free in vitro studies to predict AntiOxCIN₃ biodistribution profile, respecting the need to preserve animal health in accordance with the EU principles (Directive 2010/63/EU). Accordingly, we propose an innovative toolbox of biophysical studies and mimetic models of biological interfaces, such as nanosystems with different compositions mimicking distinct membrane barriers and human serum albumin (HSA).

Methods

Intestinal and cell membrane permeation of AntiOxCIN₃ was predicted using derivative spectrophotometry. AntiOxCIN₃ –HSA binding was evaluated by intrinsic fluorescence quenching, synchronous fluorescence, and dynamic/electrophoretic light scattering. Steady-state and time-resolved fluorescence quenching was used to predict AntiOxCIN₃-membrane orientation. Fluorescence anisotropy, synchrotron small- and wide-angle X-ray scattering were used to predict lipid membrane biophysical impairment caused by AntiOxCIN₃ distribution.

Results and Discussion

We found that AntiOxCIN₃ has the potential to permeate the gastrointestinal tract. However, its biodistribution and elimination from the body might be affected by its affinity to HSA (>90%) and by its steady-state volume of distribution (VD_SS=1.89± 0.48 L∙Kg⁻¹). AntiOxCIN₃ is expected to locate parallel to the membrane phospholipids, causing a bilayer stiffness effect. AntiOxCIN₃ is also predicted to permeate through blood-brain barrier and reach its therapeutic target – the brain.

Conclusion

Drug interactions with biological interfaces may be evaluated using membrane model systems and serum proteins. This knowledge is important for the characterization of drug partitioning, positioning and orientation of drugs in membranes, their effect on membrane biophysical properties and the study of serum protein binding. The analysis of these interactions makes it possible to collect valuable knowledge on the transport, distribution, accumulation and, eventually, therapeutic impact of drugs which may aid the drug development process.

Unraveling the Role of Drug-Lipid Interactions in NSAIDs-Induced Cardiotoxicity

Cardiovascular (CV) toxicity is nowadays recognized as a class effect of non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs). However, their mechanisms of cardiotoxicity are not yet well understood, since different compounds with similar action mechanisms exhibit distinct cardiotoxicity. For instance, diclofenac (DIC) is among the most cardiotoxic compounds, while naproxen (NAP) is associated with low CV risk. In this sense, this study aimed to unravel the role of drug-lipid interactions in NSAIDs-induced cardiotoxicity. For that, DIC and NAP interactions with lipid bilayers as model systems of cell and mitochondrial membranes were characterized by derivative spectrophotometry, fluorometric leakage assays, and synchrotron X-ray scattering. Both DIC and NAP were found to have the ability to permeabilize the membrane models, as well as to alter the bilayers’ structure. The NSAIDs-induced modifications were dependent on the lipid composition of the membrane model, the three-dimensional structure of the drug, as well as the drug:lipid molar ratio tested. Altogether, this work supports the hypothesis that NSAIDs-lipid interactions, in particular at the mitochondrial level, may be another key step among the mechanisms underlying NSAIDs-induced cardiotoxicity.

Photolysis and photocatalysis of the non-steroidal anti-inflammatory drug Nimesulide under simulated solar irradiation: Kinetic studies, transformation products and toxicity assessment

In this study, the degradation of Nimesulide (NIM), a non-steroidal anti-inflammatory drug, using photolysis, heterogeneous (TiO₂ in dispersion) and homogeneous (photo-Fenton reactant) photocatalysis, under simulated solar light (SSL) radiation, was investigated. Various parameters affecting the degradation rate of the target compound during the applied processes were optimized. The efficiency of all treatments used (direct photolysis; TiΟ₂/SSL; TiΟ₂/Η₂Ο₂/SSL; TiΟ₂/S₂Ο₈^2-/SSL; Fe³⁺/H₂O₂/SSL; Fe³⁺/S₂O₈^2-/SSL and [Fe(C₂O₄)₃]^3-/H₂O₂/SSL) was evaluated by means of initial reaction rate and mineralization. Moreover, the generated transformation products (TPs) by each basic process (photolysis; TiΟ₂/SSL and Fe³⁺/H₂O₂/SSL) were identified, using liquid chromatography coupled to high resolution mass spectrometry, and their formation kinetic profiles were given. The main transformation routes of NIM were hydroxylation and fragmentation, for all three treatments applied. Finally, toxicity measurements were conducted using Microtox bioassay in order to evaluate the potential risk of NIM and its TPs to aqueous organisms. Although, the acute toxicity increased during the first stages of treatment the final outcome lead to very low toxicity levels even within 60 min of TiO₂/SSL treatment. Concluding, the obtained results suggest that the photocatalytic degradation of NIM can lead to its complete elimination and simultaneously to the detoxification of the solution.

A Molecular Biophysical Approach to Diclofenac Topical Gastrointestinal Damage

Diclofenac (DCF), the most widely consumed non-steroidal anti-inflammatory drug (NSAID) worldwide, is associated with adverse typical effects, including gastrointestinal (GI) complications. The present study aims to better understand the topical toxicity induced by DCF using membrane models that mimic the physiological, biophysical, and chemical environments of GI mucosa segments. For this purpose, phospholipidic model systems that mimic the GI protective lining and lipid models of the inner mitochondrial membrane were used together with a wide set of techniques: derivative spectrophotometry to evaluate drug distribution at the membrane; steady-state and time-resolved fluorescence to predict drug location at the membrane; fluorescence anisotropy, differential scanning calorimetry (DSC), dynamic light scattering (DLS), and calcein leakage studies to evaluate the drug-induced disturbance on membrane microviscosity and permeability; and small- and wide-angle X-ray scattering studies (SAXS and WAXS, respectively), to evaluate the effects of DCF at the membrane structure. Results demonstrated that DCF interacts chemically with the phospholipids of the GI protective barrier in a pH-dependent manner and confirmed the DCF location at the lipid headgroup region, as well as DCF’s higher distribution at mitochondrial membrane contact points where the impairment of biophysical properties is consistent with the uncoupling effects reported for this drug.

Spectroscopic Studies as a Toolbox for Biophysical and Chemical Characterization of Lipid-Based Nanotherapeutics

The goal of this study is to provide tools to minimize trial-and-error in the development of novel lipid-based nanotherapeutics, in favor of a rational design process. For this purpose, we present case-study examples of biophysical assays that help addressing issues of lipid-based nanotherapeutics' profiling and assist in the design of lipid nanocarriers for therapeutic usage. The assays presented are rooted in spectroscopic methods (steady-state and time-resolved fluorescence; UV-Vis derivative spectroscopy; fluorescence anisotropy and fluorescence lifetime image microscopy) and allow accessing physical-chemical interactions between drugs and lipid nanocarriers, as well as studying interactions between lipid-based nanotherapeutics and membranes and/or proteins, as this is a key factor in predicting their therapeutic and off target effects. Derivative spectroscopy revealed Naproxen's high distribution (LogD ≈ 3) in different lipid-based nanocarriers (micelles and unilamellar or multilamellar vesicles) confirming the adequacy of such systems for encapsulating this anti-inflammatory drug. Fluorescence quenching studies revealed that the anti-inflammatory drugs Acemetacin and Indomethacin can reach an inner location at the lipid nanocarrier while being anchored with its carboxylic moiety at the polar headgroup. The least observed quenching effect suggested that Tolmetin is probably located at the polar headgroup region of the lipid nanocarriers and this superficial location may translate in a fast drug release from the nanocarriers. Fluorescent anisotropy measurements indicated that the drugs deeply buried within the lipid nanocarrier where the ones that had a greater fluidizing effect which can also translate in a faster drug release. The drug binding strength to serum albumin was also compared for a free drug (Clonixin) or for the same drug after encapsulation in a lipid nanocarrier DSPC:DODAP (2:1). Under both conditions there is a strong binding to serum albumin, at one binding site, suggesting the need to produce a stealth nanosystem. Finally the cellular uptake of lipid nanocarriers loaded with Daunorubicin was investigated in cancer cells using fluorescence lifetime imaging microscopy. From the images obtained it was possible to conclude that even at short incubation times (15 min) there was a distribution of the drug in the cytoplasm, whereas for longer incubation periods (4 h) the drug has reached the nucleus.

Nimesulide-induced fatal acute liver failure in an elderly woman with metastatic biliary adenocarcinoma. A case report

CONTEXT

Nimesulide is a selective inhibitor of the enzyme cyclooxygenase 2. Although considered to be a safe drug, cases of acute hepatitis and fulminant liver failure have been reported in Europe, the United States and South America, especially among elderly female patients. Until now, there had not been any reports in the literature relating to Brazilian subjects.

CASE REPORT

An 81-year old female who had been using nimesulide therapy for six days presented hematemesis and epistaxis two days before hospitalization. Clinical examination showed an extensive coagulation disorder, diffuse hematomas, hypotension and tachypnea. Laboratory tests revealed abnormalities in coagulation tests; leukocytosis; reduced platelet, hemoglobin and red blood cell counts; and elevated direct bilirubin, serum aspartate transaminase (AST), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase and renal function biomarkers. Hepatitis B and C tests were not reactive. Carcinoembryonic antigen (CEA), CA-19-9 and CA-125 levels were increased by, respectively, 1,000, 10,000 and 13 fold, whereas the alpha-fetoprotein level was normal, thus indicating a malignant tumor in the bile duct that did not originate from the liver. Thirty-six hours after hospitalization, the patient's condition worsened, leading to death. The necropsy findings included acute hepatitis with hepatocellular collapse, as well as metastasis of a carcinoma, probably from the bile duct.

CONCLUSION

Despite the carcinoma presented by the patient, nimesulide use may have contributed towards the fatal acute liver failure. Until this issue has been clarified, caution is required in prescribing nimesulide for liver disease patients.

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.

Mitochondrial membrane lipid remodeling in pathophysiology: a new target for diet and therapeutic interventions

Mitochondria are arbiters in the fragile balance between cell life and death. These organelles present an intricate membrane system, with a peculiar lipid composition and displaying transverse as well as lateral asymmetry. Some lipids are synthesized inside mitochondria, while others have to be imported or acquired in the form of precursors. Here, we review different processes, including external interventions (e.g., diet) and a range of biological events (apoptosis, disease and aging), which may result in alterations of mitochondrial membrane lipid content. Cardiolipin, the mitochondria lipid trademark, whose biosynthetic pathway is highly regulated, will deserve special attention in this review. The modulation of mitochondrial membrane lipid composition, especially by diet, as a therapeutic strategy for the treatment of some pathologies will be also addressed.

Interaction of 5-fluorouracil loaded nanoparticles with 1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes used as a cellular membrane model

Nuclear magnetic resonance (NMR) spectroscopy and steady-state fluorescence anisotropy were used to study the behavior and interaction of 5-fluorouracil, both in a free form (5FU) and included in the polymer matrix of poly(butylcyanoacrylate) nanoparticles (5FUPBCN) with a phospholipid bilayer of large unilammellar vesicles composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), as a model system of biomembranes. The results confirm an interaction and penetration of 5FU into the phospholipid bilayer of DMPC liposomes. Different mechanisms of drug transfer from the aqueous environment into the model membrane environment, for the free drug and that incorporated into polymer nanoparticles, are suggested: (i) concentration-dependent reversible diffusion of the free 5FU and (ii) sustained 5FU release from nanoparticles adsorbed on the liposome surface resulting in continuous delivery of the drug into the phospholipid bilayers of the DMPC liposomes.