Membrane Lysis Research Articles

Gram-negative synergy and mechanism of action of alkynyl bisbenzimidazoles

Bisbenzimidazoles with terminal alkynyl linkers, selective inhibitors of bacterial topoisomerase I, have been evaluated using bacterial cytological profiling (BCP) to ascertain their mechanism of action and screened for synergism to improve Gram-negative bacterial coverage. Principal component analysis of high throughput fluorescence images suggests a dual-mechanism of action affecting DNA synthesis and cell membrane integrity. Fluorescence microscopy of bacteria challenged with two of the alkynyl-benzimidazoles revealed changes in the cellular ultrastructure that differed from topoisomerase II inhibitors including induction of spheroplasts and membrane lysis. The cytoskeleton recruitment enzyme inhibitor A22 in combination with one of the alkynyl-benzimidazoles was synergistic against Acinetobacter baumannii and Escherichia coli. Gram-positive coverage remained unchanged in the A22-alkynyl bisbenzimidazole combination. Efflux inhibitors were not synergistic, suggesting that the Gram-negative outer membrane was a significant barrier for alkynyl-bisbenzimidazole uptake. Time-kill assays demonstrated the A22-bisbenzimidazole combination had a similar growth inhibition curve to that of norfloxacin in E.coli. Bisbenzimidazoles with terminal alkynyl linkers likely impede bacterial growth by compromising cell membrane integrity and by interfering with DNA synthesis against Gram-positive pathogens and in the synergistic combination against Gram-negative pathogens including E. coli and multidrug-resistant A. baumanii.

Characterization of Exon and Intron of Defensin 1 Gene in Apis cerana and Apis dorsata

Honey bee defensin 1 gene belongs to the class of immunity genes in this social insect. The peptide acts as a defensive mechanism against infections caused by Gram-positive bacteria. The aim of this study was to characterize exon 2, intron 2, and exon 3 of defensin 1 gene in both the Indonesian honey bees Apis cerana and A. dorsata. First, defensin 1 genes of A. cerana and A. dorsata were sequenced, after which a bioinformatic analysis was conducted. The amplified length of these defensin 1 genes of A. cerana and A. dorsata were 479 and 458 bp, respectively, and their putative amino acid sequences comprised 66 and 65 amino acids, respectively, with 6 cysteine residues. The cysteine residues formed a disulfide bond and then linked the three domains in the defensin peptide with each other, thereby allowing the lysis of the bacterial membrane through pore formation. Intron 2 of the defensin gene demonstrated nucleotide variations between A. cerana from Indonesia and that from Korea and between A. dorsata from Indonesia and that from Malaysia; the latter species also demonstrated variations in exon 3. Phylogenetic tree topology of the bee, which was constructed based on defensin 1 gene, was compatible with a previous study showing that A. cerana and A. dorsata are more closely related to A. mellifera than to A. florea.

Changes of the ultrastructural organization of cells of rats esophagus in the modeling of second-degree esophageal stricture

Scar strictures that lead to obstruction of the esophagus do not tend to decrease lately, but on the contrary, the number of such patients is increasing, which is caused by the use of a large range of chemicals in human life. The results of treatment of scarring strictures depend on the degree of stenosis. With complete obstruction of the esophagus, the question arises about conducting surgical treatment. Methods of correction of esophageal strictures have a considerable number of postoperative complications and lethal consequences – from 5.0 % to 15.0 %. Therefore, in order to create a unified pathogenetic tactic for the management and treatment of esophageal strictures, we were offered to study the ultrastructural changes of the mucous membrane of the stricture of the second stage during its modeling in the experiment. The purpose of the work is to investigate the dynamics of ultrastructural changes of the mucous membrane of the esophagus wall in the normal and second stage of its stricture. The experimental study was performed on adult white male rats weighing between 250 and 300 g. A total of 16 animals were operated on, which were divided into 2 groups: a control group (6 rats) and a study group (10 rats). The studies were performed under ketamine anesthesia. In animals of the control group performed only laparotomy, followed by layer-by-layer suturing of the anterior abdominal wall. In animals of the study group created a model of obstruction of the esophagus of the second stage. Electron microscopic examination was performed on days 3, 4, and 5 of the experiment, eliminating animals by overdosing on ketamine. As a result of the electron microscopic study of the ultrastructural organization of basal, spinosum, superficial epitheliocytes of stratified squamous epithelium without keratin, smooth muscle myocytes of the muscular plate and contractile elements of the muscular layer of the esophagus of rats with simulated stricture of the second degree revealed dystrophic and destructive disorders that varied in depth and severity. It was established that mitochondrial dysfunction leads to a decrease in the activity of reparative, metabolic and synthetic processes of the cell, which is indirectly manifested by a decrease in ribosomes and polysomes in the cytoplasm, loosening and focal lysis of membranes of the granular endoplasmic reticulum. Stricture of esophagus of the second stage causes activation of catabolic intracellular processes in all cells, which is morphologically confirmed by the appearance in the cytoplasm of secondary lysosomes and inclusions of lipids.

Phytochemical and Pharmacological Potential of Enhydra fluctuans Available in Bangladesh

Objectives: The possible phytochemical constituents, thrombolytic and membrane stabilizing activities of the crude ethanolic extract of Enhydra fluctuans (CE) were investigated along with the antimicrobial, antioxidant and cytotoxic potentials of its petroleum ether (PESF), carbon tetrachloride (CTCSF), chloroform (CSF) and aqueous (AQSF) soluble fractions.
 Materials & Methods: The coarse leaf powder was extracted at room temperature with ethanol. Solvent-solvent partitioning was done to obtain the four soluble fractions. Anticoagulant potential was determined by the in vitro thrombolytic model, membrane stabilization method was used to assess in vitro anti-inflammatory activity, the disc diffusion method was used for anti-microbial screening, antioxidant potential was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and brine shrimp lethality bioassay method was used for cytotoxic activity determination.
 Results: Chemical screening of the crude extract evidenced the presence of alkaloids, saponins, tannins, flavonoids, reducing sugars and gums. It showed significant clot lysis property of 46.91%. It also significantly inhibited heat and hypotonic solution induced lysis of the human red blood cell membrane with values of 71.80% and 47.60%, respectively. CTCSF and PESF showed mild antimicrobial activity. AQSF showed most prominent antioxidant activity with IC50 value of 12.27 µg/mL. CTCSF showed LC50 value of 0.84 µg/mL, with most potent cytotoxic activity.
 Conclusion: Significant thrombolytic, membrane stabilizing, antioxidant and in vitro cytotoxic activities of the ethanolic plant extract were observed in this study. In vivo activities and isolation of active compound(s) from this extract are yet to be investigated.

Rhabdomyolysis and spine surgery: A systematic review of the literature

Rhabdomyolysis is characterized by the rupture of skeletal muscles due to a lot of reasons such as exercise, drug addiction, toxins, infections, trauma and some medications. The etiology of postoperative rhabdomyolysis is potentially multifactorial and has been documented in several types of surgery. The lysis of cell membrane releases organic and inorganic intracellular components that can be toxic and life threatening. Creatinephosphokinase (CPK) is one of the components and it is the most sensitive indicator of myocyte injury. The classic triad of symptoms is characterized by myalgia, weakness and brown-red urine. There is not a clearly agreed level of serum CPK that is evident for diagnosis of rhabdomyolysis. However, a CPK level higher than 5 times of its normal value is accepted by many authors as diagnostic criteria. Acute kidney injury is the most serious complication of rhabdomyolysis in the days following initial presentation and develops in 33% of patients. The objective of this study was to perform a review of the literature, aiming at a better understanding about the changes in CPK levels and the frequency of rhabdomyolysis in spine surgery, with special attention in posterior lumbar fusion. Nineteen studies were selected for analysis. The studies had different characteristics considering patients age, body mass index, comorbidities and type of surgery. The best available evidence points out to the prognosis depend on the extension and clinical severity of rhabdomyolysis, as well as on the early and prompt medical intervention.

Endophyte Bacillus velezensis Isolated from Citrus spp. Controls Streptomycin-Resistant Xanthomonas citri subsp. citri That Causes Citrus Bacterial Canker

Citrus bacterial canker (CBC), caused by the plant pathogenic bacterium Xanthomonas citri subsp. citri (Xcc), is a devastating disease in many commercial citrus cultivars. Every year, CBC causes a substantial reduction in fruit quality and quantity that corresponds to significant economic losses worldwide. Endophytic microorganisms produce numerous bioactive secondary metabolites that can control plant pathogens. We investigated the antagonistic activities of 66 endophytic bacteria isolated from nine citrus cultivars to control streptomycin-resistant Xcc. The suspension of Endophytic Bacteria-39 (EB-39), identified as Bacillus velezensis, exhibited the highest antibacterial activity against three wild-type and six streptomycin-resistant Xcc strains, with the inhibition zones between 39.47 ± 1.6 and 45.31 ± 1.6 mm. The ethyl acetate extract of EB-39 also controlled both wild-type and streptomycin-resistant Xcc strains, with the inhibition zones between 29.28 ± 0.6 and 33.88 ± 1.3 mm. Scanning electron microscopy indicated the ethyl acetate extract of EB-39-induced membrane damage and lysis. The experiments using the detached leaves of a susceptible Citrus species showed that EB-39 significantly reduced the incidence of canker on the infected leaves by 38%. These results strongly suggest that our newly isolated EB-39 is a novel biocontrol agent against CBC caused by wild-type and streptomycin-resistant Xcc strains.

Design of stapled antimicrobial peptides that are stable, nontoxic and kill antibiotic-resistant bacteria in mice.

The clinical translation of cationic alpha-helical antimicrobial peptides (AMPs) has been hindered by structural instability, proteolytic degradation, and in vivo toxicity from non-specific membrane lysis. Although analyses of hydrophobic content and charge distribution have informed the design of synthetic AMPs with increased potency and reduced in vitro hemolysis, non-specific membrane toxicity in vivo continues to impede AMP drug development. Here, we analyzed a 58-member library of stapled AMPs (StAMPs) based on Magainin-II, and applied the insights from structure-function-toxicity measurements to devise an algorithm for the design of stable, protease-resistant, potent, and nontoxic StAMP prototypes. We show that a lead double-stapled StAMP named Mag(i+4)1,15(A9K,B21A,N22K,S23K) can kill multidrug resistant Gram-negative pathogens, such as colistin-resistant Acinetobacter baumannii in a mouse peritonitis-sepsis model, without observed hemolysis or renal injury in murine toxicity studies. Inputting the amino acid sequences alone, we further generated membrane-selective StAMPs of pleurocidin, CAP18, and esculentin, highlighting the generalizability of our design platform.

Photothermal-Induced Antibacterial Activity of Gold Nanorods Loaded into Polymeric Hydrogel against Pseudomonas aeruginosa Biofilm.

In this study, the photothermal-induced bactericidal activity of phospholipid-decorated gold nanorods (DSPE-AuNR) suspension against Pseudomonas aeruginosa planktonic and biofilm cultures was investigated. We found that the treatment of planktonic culture of Pseudomonas aeruginosa with DSPE-AuNR suspension (0.25–0.03 nM) followed by a continuous laser beam exposure resulted in ~6 log cycle reduction of the bacterial viable count in comparison to the control. The percentage reduction of Pseudomonas aeruginosa biofilm viable count was ~2.5–6.0 log cycle upon laser excitation with different concentrations of DSPE-AuNR as compared to the control. The photothermal ablation activity of DSPE-AuNR (0.125 nM) loaded into poloxamer 407 hydrogel against Pseudomonas aeruginosa biofilm resulted in ~4.5–5 log cycle reduction in the biofilm viable count compared to the control. Moreover, transmission electron microscope (TEM) images of the photothermally-treated bacteria revealed a significant change in the bacterial shape and lysis of the bacterial cell membrane in comparison to the untreated bacteria. Furthermore, the results revealed that continuous and pulse laser beam modes effected a comparable photothermal-induced bactericidal activity. Therefore, it can be concluded that phospholipid-coated gold nanorods present a promising nanoplatform to eradicate Pseudomonas aeruginosa biofilm responsible for common skin diseases.

Phytochemical screening and evaluation of pharmacological activities of aqueous extract of Typhonium trilobatum (L.) Schott

This study aimed at phytochemical analysis and evaluation of toxic and protective effects of the crude aqueous extract of Typhonium trilobatum. Toxicity analysis was done in Allium cepa, while anti-inflammatory, and membrane stabilizing and clotlysis capacity were tested by using egg albumin and human erythrocytes, respectively. The results suggest that T. trilobatum aqueous extract contains alkaloids, glycosides, tannins, saponins, flavonoids and reducing sugars. The crude extract exhibited toxicity in A. cepa in a time and concentration dependent manner. The highest root growth inhibition was observed at exposure time 72 h in 20% (v/v) concentration extract of the herb. The extract at low concentration (2.5 and 5%) reduced the root growth inhibition capacity at 48 h in comparison to 24 and 72 h, possibly by adaptation of DNA damage profile in the eukaryotic test system (A. cepa), which was further confirmed in anti-inflammatory and membrane stabilizing, and anti-atherothrombosis test. In the latter cases, the extract at 0.02–0.08% (v/v) significantly (p < 0.05, p < 0.01, p < 0.001) inhibited protein denaturation, membrane lysis, while enhanced clotlysis capacity in a concentration-dependent manner. In conclusion, the extract exerted toxic effects at high concentrations and protective effects at low concentrations. T. trilobatum may be one of the potential sources of phytotherapeutic agents, especially for the treatment of inflammatory and cardiovascular diseases and disorders.

In Silico Prediction of Hemolytic Toxicity on the Human Erythrocytes for Small Molecules by Machine-Learning and Genetic Algorithm.

Hemolytic toxicity of small molecules, as one of the important ADMET end points, can cause the lysis of erythrocytes membrane and leaking of hemoglobin into the blood plasma, which leads to various side effects. Thus, it is very crucial to assess the hemolytic potential of small molecules during the early stage of drug development process. However, so far there is no computational model to predict the human hemolytic toxicity of small molecules. To this end, we manually curate the hemolytic toxicity data set for the small molecules experimentally evaluated on the human erythrocytes, develop the first machine-learning (ML) based models to predict the human hemolytic toxicity of small molecules, harness the genetic algorithm (GA) and ML based model to optimize human hemolytic toxicity based on the molecular fingerprint to derive "optimal virtual fingerprints (OVFs)" with the desired hemolytic/nonhemolytic property, and finally implement a free software for the users to predict/optimize the human hemolytic toxicity with ML and GA in the automatic manner.

Development of a neurotoxicity assay that is tuned to detect mitochondrial toxicants

Many neurotoxicants affect energy metabolism in man, but currently available test methods may still fail to predict mito- and neurotoxicity. We addressed this issue using LUHMES cells, i.e., human neuronal precursors that easily differentiate into mature neurons. Within the NeuriTox assay, they have been used to screen for neurotoxicants. Our new approach is based on culturing the cells in either glucose or galactose (Glc–Gal–NeuriTox) as the main carbohydrate source during toxicity testing. Using this Glc–Gal–NeuriTox assay, 52 mitochondrial and non-mitochondrial toxicants were tested. The panel of chemicals comprised 11 inhibitors of mitochondrial respiratory chain complex I (cI), 4 inhibitors of cII, 8 of cIII, and 2 of cIV; 8 toxicants were included as they are assumed to be mitochondrial uncouplers. In galactose, cells became more dependent on mitochondrial function, which made them 2–3 orders of magnitude more sensitive to various mitotoxicants. Moreover, galactose enhanced the specific neurotoxicity (destruction of neurites) compared to a general cytotoxicity (plasma membrane lysis) of the toxicants. The Glc–Gal–NeuriTox assay worked particularly well for inhibitors of cI and cIII, while the toxicity of uncouplers and non-mitochondrial toxicants did not differ significantly upon glucose ↔ galactose exchange. As a secondary assay, we developed a method to quantify the inhibition of all mitochondrial respiratory chain functions/complexes in LUHMES cells. The combination of the Glc–Gal–NeuriTox neurotoxicity screening assay with the mechanistic follow up of target site identification allowed both, a more sensitive detection of neurotoxicants and a sharper definition of the mode of action of mitochondrial toxicants.

Battacin-Inspired Ultrashort Peptides: Nanostructure Analysis and Antimicrobial Activity.

Peptides can serve as versatile therapeutics with a highly modular structure and tunable biophysical properties. In particular, the efficacy of peptide antibiotics against drug-resistant pathogens is of great promise, as few new classes of antibiotics are being developed to overcome the ever-increasing bacterial resistance to contemporary drugs. This work reports biophysical and antimicrobial studies of a designed library of ultrashort peptides that self-assemble into hydrogels at concentrations as low as 0.5% w/v in buffered saline, as confirmed by rheology. The hydrogels are constituted by β-sheet-rich nanofibril networks, as determined by biophysical techniques including spectroscopy (attenuated total reflectance Fourier transform infrared spectroscopy and Congo red binding assay), short- and wide-angle X-ray scattering, and electron microscopy. Both peptide solutions and self-assembled hydrogels show potent antimicrobial activity against S. aureus and Pseudomonas aeruginosa by membrane lysis. These peptides also displayed selectivity toward bacterial cells over human dermal fibroblasts in vitro, as determined from Live/Dead, scanning electron microscopy, and coculture assays. This work reports an antimicrobial self-assembling motif of only three residues comprising an aromatically acylated cationic d-Dab/Lys amino acid, a second cationic residue, and naphthylalanine that heavily influences the self-assembly of these peptides into hydrogels. The variations in the antimicrobial activity and self-assembly properties between analogues may have implications in future studies on the correlation between self-assembly and biological activity in ultrashort peptides.

Mechanics and Dynamics of Bacterial Cell Lysis

Membrane lysis, or rupture, is a cell death pathway in bacteria frequently caused by cell wall-targeting antibiotics. Although previous studies have clarified the biochemical mechanisms of antibiotic action, a physical understanding of the processes leading to lysis remains lacking. Here, we analyze the dynamics of membrane bulging and lysis in Escherichia coli, in which the formation of an initial, partially subtended spherical bulge (“bulging”) after cell wall digestion occurs on a characteristic timescale of 1 s and the growth of the bulge (“swelling”) occurs on a slower characteristic timescale of 100 s. We show that bulging can be energetically favorable due to the relaxation of the entropic and stretching energies of the inner membrane, cell wall, and outer membrane and that the experimentally observed timescales are consistent with model predictions. We then show that swelling is mediated by the enlargement of wall defects, after which cell lysis is consistent with both the inner and outer membranes exceeding characteristic estimates of the yield areal strains of biological membranes. These results contrast biological membrane physics and the physics of thin, rigid shells. They also have implications for cellular morphogenesis and antibiotic discovery across different species of bacteria.

Externalized histone H4 orchestrates chronic inflammation by inducing lytic cell death.

The perpetuation of inflammation is an important pathophysiological contributor to the global medical burden. Chronic inflammation is promoted by non-programmed cell death1,2; however, how inflammation is instigated, its cellular and molecular mediators, and its therapeutic value are poorly defined. Here we use mouse models of atherosclerosis-a major underlying cause of mortality worldwide-to demonstrate that extracellular histone H4-mediated membrane lysis of smooth muscle cells (SMCs) triggers arterial tissue damage and inflammation. We show that activated lesional SMCs attract neutrophils, triggering the ejection of neutrophil extracellular traps that contain nuclear proteins. Among them, histone H4 binds to and lyses SMCs, leading to the destabilization of plaques; conversely, the neutralization of histone H4 prevents cell death of SMCs and stabilizes atherosclerotic lesions. Our data identify a form of cell death found at the core of chronic vascular disease that is instigated by leukocytes and can be targeted therapeutically.

Polydopamine-Decorated Orlistat-Loaded Hollow Capsules with an Enhanced Cytotoxicity against Cancer Cell Lines.

Orlistat, an FDA-approved antiobesity drug, has recently been shown to have anticancer effects. However, orlistat is extremely hydrophobic with low absorption. Therefore, new approaches are needed to effectively deliver orlistat for cancer therapy. Herein, we developed a fast and simple method to use polydopamine-coated hollow capsule (PHC) as a drug nanocarrier for enhancing the therapeutic effects of orlistat. Orlistat-loaded PHC had an average size of 200 nm, which was characterized by using dynamic light scattering and scanning electron microscope. Furthermore, the polydopamine layer provided an excellent control of orlistat release because it was extremely sensitive to pH values. The cellular uptake and cytotoxicity experiments were performed to show that orlistat packaged in PHC could be endocytosed into cells and then significantly improved the cytotoxic activity against cancer cell lines in a short time compared with free orlistat. Moreover, dynamic study of cell membrane lysis was performed by staining with the LIVE/DEAD kit to demonstrate the cancer-killing mechanism. The size of the cell surface area has also been proven to be a key parameter which affected drug efficacy. Taken all together, these results present that orlistat-loaded PHC is a very promising formula for cancer treatments.

Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement.

The antimicrobial effects of Laponite nanoparticles with or without loading of the antimicrobial peptide LL-37 was investigated along with their membrane interactions. The study combines data from ellipsometry, circular dichroism, fluorescence spectroscopy, particle size/ζ potential measurements, and confocal microscopy. As a result of the net negative charge of Laponite, loading of net positively charged LL-37 increases with increasing pH. The peptide was found to bind primarily to the outer surface of the Laponite nanoparticles in a predominantly helical conformation, leading to charge reversal. Despite their net positive charge, peptide-loaded Laponite nanoparticles did not kill Gram-negative Escherichia coli bacteria or disrupt anionic model liposomes. They did however cause bacteria flocculation, originating from the interaction of Laponite and bacterial lipopolysaccharide (LPS). Free LL-37, in contrast, is potently antimicrobial through membrane disruption but does not induce bacterial aggregation in the concentration range investigated. Through LL-37 loading of Laponite nanoparticles, the combined effects of bacterial flocculation and membrane lysis are observed. However, bacteria aggregation seems to be limited to Gram-negative bacteria as Laponite did not cause flocculation of Gram-positive Bacillus subtilis bacteria nor did it bind to lipoteichoic acid from bacterial envelopes. Taken together, the present investigation reports several novel phenomena by demonstrating that nanoparticle charge does not invariably control membrane destabilization and by identifying the ability of anionic Laponite nanoparticles to effectively flocculate Gram-negative bacteria through LPS binding. As demonstrated in cell experiments, such aggregation results in diminished LPS-induced cell activation, thus outlining a promising approach for confinement of infection and inflammation caused by such pathogens.

Symmetrical Modification of Minimized Dermaseptins to Extend the Spectrum of Antimicrobials with Endotoxin Neutralization Potency.

Antimicrobial peptides (AMPs) have emerged as a promising class of antimicrobial agents that could potentially address the global antibiotic resistance. Generating mirror-like peptides by minimizing dermaseptin family sequences is an effective strategy for designing AMPs. However, the previous research still had some limitations such as lower effectiveness and a narrow spectrum of antibacterial activity. To further expand and hone this strategy, we designed a series of AMPs consisting of the WXMXW-NH2 motif (X represents V, I, F, and W; M represents KAAAKAAAK). The peptides formed α-helices and displayed broad-spectrum antimicrobial activities against eleven types of clinical bacteria including both Gram-negative and Gram-positive bacteria. The optimized peptide WW exhibited high physical rupture by inducing membrane shrinkage, disruption, and lysis. Moreover, WW effectively neutralized endotoxins and inhibited the inflammatory response while having the highest therapeutic index. In conclusion, these results indicated that the peptide WW has potential as a broad-spectrum antimicrobial agent or preservative for overcoming the risk of multidrug resistance in localized or external therapeutic applications.

Micropatterned Viral Membrane Clusters for Antiviral Drug Evaluation.

The function of biological nanoparticles, such as membrane-enveloped viral particles, is often enhanced when the particles form higher-order supramolecular assemblies. While there is intense interest in developing biomimetic platforms that recapitulate these collective properties, existing platforms are limited to mimicking individual virus particles. Here, we present a micropatterning strategy to print linker molecules selectively onto bioinert surfaces, thereby enabling controlled tethering of biomimetic viral particle clusters across defined geometric patterns. By controlling the linker concentration, it is possible to tune the density of tethered particles within clusters while enhancing the signal intensity of encapsulated fluorescent markers. Time-resolved tracking of pore formation and membrane lysis revealed that an antiviral peptide can disturb clusters of the membrane-enclosed particles akin to the targeting of individual viral particles. This platform is broadly useful for evaluating the performance of membrane-active antiviral drug candidates, whereas the micropatterning strategy can be applied to a wide range of biological nanoparticles and other macromolecular entities.

Statins, myalgia, and rhabdomyolysis.

Statin-associated muscle symptoms (SAMSs) vary considerably in frequency and severity, with a spectrum extending from myalgia with normal creatine kinase (CK) levels or asymptomatic hyperCKemia to potentially life-threatening rhabdomyolysis and necrotizing autoimmune myopathy. Myalgia with CK elevation is the most common presentation. Onset is usually within 1 month after statin initiation or dosage intensification, and the symptoms can be expected to resolve within a few weeks after treatment discontinuation. The mechanism of muscle injury combines statin accumulation within muscles, which varies with the type and dosage of the drug; muscle fragility; abnormalities in statin transport or liver metabolism; drug-drug interactions; and genetic susceptibility. HMG-CoA reductase inhibition in muscles by statins exerts pleiotropic effects that can affect energy metabolism, induce mitochondrial dysfunction, modify lipid oxidation, promote apoptosis and cell membrane lysis, alter muscle protein synthesis, or trigger an autoimmune process. Statins are used to treat several chronic conditions and comorbidities, including inflammatory rheumatic diseases, which are associated with an increased cardiovascular risk. When the cardiovascular risk is high or very high, statin therapy is indispensable and has a very favorable risk/benefit ratio. Otherwise, the risks should be weighed against the benefits before reinitiating statin therapy, and a different statin or lower dosage should be used. If statin therapy cannot be successfully reintroduced, other classes of lipid-lowering drugs should be considered. Severe SAMSs with major weakness and marked CK elevation should suggest the rare eventuality of necrotizing autoimmune myopathy and prompt an anti-HMGCR antibody assay and muscle biopsy to ensure that immunosuppressant therapy is started rapidly if needed.

Coarse-Grained Simulations of the Pathway to Membrane Lysis

Coarse-Grained Simulations of the Pathway to Membrane Lysis