Microbubble-mediated sonoporation amplified lipid peroxidation of Jurkat cells

Immunomodulation of human T cells by microbubble-mediated focused ultrasound

While met with initial and ground-breaking success targeting blood borne cancers, cellular immunotherapy remains significantly hindered in the context of solid tumors by the tumor microenvironment. Focused ultrasound, in conjunction with microbubbles, has found tremendous potential as a targeted and local drug/gene delivery technique for cancer therapy. The specific immunomodulating effects of this technique on immune cells, including T-cells, remain unexplored. Here, with freshly isolated human immune cells, we examine how focused ultrasound can viably modulate immune cell membrane permeability and influence the secretion of over 90 cytokines, chemokines and other analytes relevant to a potent immune response against cancer. We determine that microbubble-mediated focused ultrasound modulates the immune cell secretome in a time-dependent manner - ranging in ~0.1-3.6-fold changes in the concentration of a given cytokine compared to sham controls over 48 hours post-treatment (e.g. IL-1β, TNF-α, CX3CL1, CCL21). Further, we determine the general trend of a negative correlation between secreted cytokine concentration and viable ultrasound-assisted membrane permeability with negligible loss of cell viability. Taken together, the data presented here highlights the potential of microbubble-mediated focused ultrasound to viably enhance T-cell permeability and modulate key pro-immune pathways, offering a novel approach to augment targeted cellular therapies for solid tumors.

Calcium ion delivery by microbubble-assisted sonoporation stimulates cell death in human gastrointestinal cancer cells

Ultrasound-mediated cell membrane permeabilization - sonoporation, enhances drug delivery directly to tumor sites while reducing systemic side effects. The potential of ultrasound to augment intracellular calcium uptake - a critical regulator of cell death and proliferation - offers innovative alternative to conventional chemotherapy. However, calcium therapeutic applications remain underexplored in sonoporation studies. This research provides a comprehensive analysis of calcium sonoporation (CaSP), which combines ultrasound treatment with calcium ions and SonoVue microbubbles, on gastrointestinal cancer cells LoVo and HPAF-II. Initially, optimal sonoporation parameters were determined: an acoustic wave of 1 MHz frequency with a 50 % duty cycle at intensity of 2 W/cm2. Subsequently, various cellular bioeffects, such as viability, oxidative stress, metabolism, mitochondrial function, proliferation, and cell death, were assessed following CaSP treatment. CaSP significantly impaired cancer cell function by inducing oxidative and metabolic stress, evidenced by increased mitochondrial depolarization, decreased ATP levels, and elevated glucose uptake in a Ca2+ dose-dependent manner, leading to activation of the intrinsic apoptotic pathway. Cellular response to CaSP depended on the TP53 gene's mutational status: colon cancer cells were more susceptible to CaSP-induced apoptosis and G1 phase cell cycle arrest, whereas pancreatic cancer cells showed a higher necrotic response and G2 cell cycle arrest. These promising results encourage future research to optimize sonoporation parameters for clinical use, investigate synergistic effects with existing treatments, and assess long-term safety and efficacy in vivo. Our study highlights CaSP's clinical potential for improved safety and efficacy in cancer therapy, offering significant implications for the pharmaceutical and biomedical fields.

Landscape of Cellular Bioeffects Triggered by Ultrasound-Induced Sonoporation

Sonoporation is the process of transient pore formation in the cell membrane triggered by ultrasound (US). Numerous studies have provided us with firm evidence that sonoporation may assist cancer treatment through effective drug and gene delivery. However, there is a massive gap in the body of literature on the issue of understanding the complexity of biophysical and biochemical sonoporation-induced cellular effects. This study provides a detailed explanation of the US-triggered bioeffects, in particular, cell compartments and the internal environment of the cell, as well as the further consequences on cell reproduction and growth. Moreover, a detailed biophysical insight into US-provoked pore formation is presented. This study is expected to review the knowledge of cellular effects initiated by US-induced sonoporation and summarize the attempts at clinical implementation.

Oxidation of Membrane Lipids Alters the Activity of the Human Serotonin 1A Receptor

Lipid oxidation has significant effects on lipid bilayer properties; these effects can be expected to extend to interactions between the lipid bilayer and integral membrane proteins. Given that G protein-coupled receptor (GPCR) activity is known to depend on the properties of the surrounding lipid bilayer, these proteins represent an intriguing class of molecules in which the impact of lipid oxidation on protein behavior is studied. Here, we study the effects of lipid oxidation on the human serotonin 1A receptor (5-HT_1AR). Giant unilamellar vesicles (GUVs) containing integral 5-HT_1AR were fabricated by the hydrogel swelling method; these GUVs contained polyunsaturated 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine (PLinPC) and its oxidation product 1-palmitoyl-2-(9'-oxo-nonanoyl)-sn-glycero-3-phosphocholine (PoxnoPC) at various ratios. 5-HT_1AR-integrated GUVs were also fabricated from lipid mixtures that had been oxidized by extended exposure to the atmosphere. Both types of vesicles were used to evaluate 5-HT_1AR activity using an assay to quantify GDP-GTP exchange by the coupled G protein α subunit. Results indicated that 5-HT_1AR activity increases significantly in bilayers containing oxidized lipids. This work is an important step in understanding how hyperbaric oxidation can change plasma membrane properties and lead to physiological dysfunction.

Moving forward with isoprostanes, neuroprostanes and phytoprostanes: where are we now?

Polyunsaturated fatty acids (PUFAs) are essential components in eukaryotic cell membrane. They take part in the regulation of cell signalling pathways and act as precursors in inflammatory metabolism. Beside these, PUFAs auto-oxidize through free radical initiated mechanism and release key products that have various physiological functions. These products surfaced in the early nineties and were classified as prostaglandin isomers or isoprostanes, neuroprostanes and phytoprostanes. Although these molecules are considered robust biomarkers of oxidative damage in diseases, they also contain biological activities in humans. Conceptual progress in the last 3 years has added more understanding about the importance of these molecules in different fields. In this chapter, a brief overview of the past 30 years and the recent scope of these molecules, including their biological activities, biosynthetic pathways and analytical approaches are discussed.

Isoprostanoid Profiling of Marine Microalgae

Algae result from a complex evolutionary history that shapes their metabolic network. For example, these organisms can synthesize different polyunsaturated fatty acids, such as those found in land plants and oily fish. Due to the presence of numerous double-bonds, such molecules can be oxidized nonenzymatically, and this results in the biosynthesis of high-value bioactive metabolites named isoprostanoids. So far, there have been only a few studies reporting isoprostanoid productions in algae. To fill this gap, the current investigation aimed at profiling isoprostanoids by liquid chromatography -mass spectrometry/mass spectrometry (LC-MS/MS) in four marine microalgae. A good correlation was observed between the most abundant polyunsaturated fatty acids (PUFAs) produced by the investigated microalgal species and their isoprostanoid profiles. No significant variations in the content of oxidized derivatives were observed for Rhodomonas salina and Chaetoceros gracilis under copper stress, whereas increases in the production of C18-, C20- and C22-derived isoprostanoids were monitored in Tisochrysis lutea and Phaeodactylum tricornutum. In the presence of hydrogen peroxide, no significant changes were observed for C. gracilis and for T. lutea, while variations were monitored for the other two algae. This study paves the way to further studying the physiological roles of isoprostanoids in marine microalgae and exploring these organisms as bioresources for isoprostanoid production.

Endothelial Cells, First Target of Drug Delivery Using Microbubble-Assisted Ultrasound

Microbubble-assisted ultrasound has emerged as a promising method for local drug delivery. Microbubbles are intravenously injected and locally activated by ultrasound, thus increasing the permeability of vascular endothelium for facilitating extravasation and drug uptake into the treated tissue. Thereby, endothelial cells are the first target of the effects of ultrasound-driven microbubbles. In this review, the in vitro and in vivo bioeffects of this method on endothelial cells are described and discussed, including aspects on the permeabilization of biologic barriers (endothelial cell plasma membranes and endothelial barriers), the restoration of their integrity, the molecular and cellular mechanisms involved in both these processes, and the resulting intracellular and intercellular consequences. Finally, the influence of the acoustic settings, microbubble parameters, treatment schedules and flow parameters on these bioeffects are also reviewed.

Optimization of Free Phytoprostane and Phytofuran Production by Enzymatic Hydrolysis of Pea Extracts Using Esterases

Given the growing interest in phytoprostanes (PhytoPs) and phytofurans (PhytoFs) in the fields of plant physiology, biotechnology, and biological function, the present study aims to optimize a method of enzymatic hydrolysis that utilizes bacterial and yeast esterases that allow the appropriate quantification of PhytoPs and PhytoFs. To obtain the highest concentration of PhytoPs and PhytoFs, a response surface methodology/Box-Behnken design was used to optimize the hydrolysis conditions. Based on the information available in the literature on the most critical parameters that influence the activity of esterases, the three variables selected for the study were temperature (°C), time (min), and enzyme concentration (%). The optimal hydrolysis conditions retrieved differed between PhytoPs (21.5 °C, 5.7 min, and 0.61 μg of enzyme per reaction) and PhytoFs (20.0 °C, 5.0 min, and 2.17 μg of enzyme per reaction) and provided up to 25.1- and 1.7-fold higher contents relative to nonhydrolyzed extracts. The models were validated by comparing theoretical and experimental values for PhytoP and PhytoF yields (1.01 and 1.06 theoretical/experimental rates, respectively). The optimal conditions were evaluated for their relative influence on the yield of individual nonesterified PhytoPs and PhytoFs to define the limitations of the models for obtaining the highest concentration of most considered compounds. In conclusion, the models developed provided valuable alternatives to the currently applied methods using unspecific alkaline hydrolysis to obtain free nonesterified PhytoPs and PhytoFs, which give rise to more specific hydrolysis of PhytoP and PhytoF esters, reducing the degradation of free compounds by classical chemical procedures.

Minireview: Biophysical Mechanisms of Cell Membrane Sonopermeabilization. Knowns and Unknowns

Microbubble-assisted ultrasound has emerged as a promising method for the delivery of low-molecular-weight chemotherapeutic molecules, nucleic acids, therapeutic peptides, and antibodies in vitro and in vivo. Its clinical applications are under investigation for local delivery drug in oncology and neurology. However, the biophysical mechanisms supporting the acoustically mediated membrane permeabilization are not fully established. This review describes the present state of the investigations concerning the acoustically mediated stimuli (i.e., mechanical, chemical, and thermal stimuli) as well as the molecular and cellular actors (i.e., membrane pores and endocytosis) involved in the reversible membrane permeabilization process. The different hypotheses, which were proposed to give a biophysical description of the membrane permeabilization, are critically discussed.

Obesogenic diet in aging mice disrupts gut microbe composition and alters neutrophil:lymphocyte ratio, leading to inflamed milieu in acute heart failure

Calorie-dense obesogenic diet (OBD) is a prime risk factor for cardiovascular disease in aging. However, increasing age coupled with changes in the diet can affect the interaction of intestinal microbiota influencing the immune system, which can lead to chronic inflammation. How age and calorie-enriched OBD interact with microbial flora and impact leukocyte profiling is currently under investigated. Here, we tested the interorgan hypothesis to determine whether OBD in young and aging mice alters the gut microbe composition and the splenic leukocyte profile in acute heart failure (HF). Young (2-mo-old) and aging (18-mo-old) mice were supplemented with standard diet (STD, ∼4% safflower oil diet) and OBD (10% safflower oil) for 2 mo and then subjected to coronary artery ligation to induce myocardial infarction. Fecal samples were collected pre- and post-diet intervention, and the microbial flora were analyzed using 16S variable region 4 rRNA gene DNA sequencing and Quantitative Insights Into Microbial Ecology informatics. The STD and OBD in aging mice resulted in an expansion of the genus Allobaculum in the fecal microbiota. However, we found a pathologic change in the neutrophil:lymphocyte ratio in aging mice in comparison with their young counterparts. Thus, calorie-enriched OBD dysregulated splenic leukocytes by decreasing immune-responsive F4/80+ and CD169+ macrophages in aging mice. OBD programmed neutrophil swarming with an increase in isoprostanoid levels, with dysregulation of lipoxygenases, cytokines, and metabolite-sensing receptor expression. In summary, calorie-dense OBD in aging mice disrupted the composition of the gut microbiome, which correlates with the development of integrative and system-wide nonresolving inflammation in acute HF.-Kain, V., Van Der Pol, W., Mariappan, N., Ahmad, A., Eipers, P., Gibson, D. L., Gladine, C., Vigor, C., Durand, T., Morrow, C., Halade, G. V. Obesogenic diet in aging mice disrupts gut microbe composition and alters neutrophil:lymphocyte ratio, leading to inflamed milieu in acute heart failure.

Spatially Specific Liposomal Cancer Therapy Triggered by Clinical External Sources of Energy

This review explores the use of energy sources, including ultrasound, magnetic fields, and external beam radiation, to trigger the delivery of drugs from liposomes in a tumor in a spatially-specific manner. Each section explores the mechanism(s) of drug release that can be achieved using liposomes in conjunction with the external trigger. Subsequently, the treatment's formulation factors are discussed, highlighting the parameters of both the therapy and the medical device. Additionally, the pre-clinical and clinical trials of each triggered release method are explored. Lastly, the advantages and disadvantages, as well as the feasibility and future outlook of each triggered release method, are discussed.

Breast Cancer Cell Line Phenotype Affects Sonoporation Efficiency Under Optimal Ultrasound Microbubble Conditions

Background

Ultrasound/microbubble (USMB)-mediated sonoporation is a new strategy with minimal procedural invasiveness for targeted and site-specific drug delivery to tumors. The purpose of this study was to explore the effect of different breast cancer cell lines on sonoporation efficiency, and then to identify an optimal combination of USMB parameters to maximize the sonoporation efficiency for each tumor cell line.

Material/Methods

Three drug-sensitive breast cell lines – MCF-7, MDA-MB-231, and MDA-MB-468 – and 1 multidrug resistance (MDR) cell line – MCF-7/ADR – were chosen. An orthogonal array experimental design approach based on 3 levels of 3 parameters (A: microbubble concentration, 10%, 20%, and 30%, B: sound intensity, 0.5, 1.0, and 1.5 W/cm², C: irradiation time, 30, 60, and 90 s) was employed to optimize the sonoporation efficiency.

Results

The optimal USMB parameter combinations for different cell lines were diverse. Under optimal parameter combinations, the maximum sonoporation efficiency differences between different breast tumor cell lines were statistically significant (MDA-MB-231: 46.70±5.79%, MDA-MB-468: 53.44±5.69%, MCF-7: 59.88±5.53%, MCF-7/ADR: 65.39±4.01%, P<0.05), so were between drug-sensitive cell line and MDR cell line (MCF-7: 59.88±5.53%, MCF-7/ADR: 65.39±4.01%, p=0.026).

Conclusions

Different breast tumor cell lines have their own optimal sonoporation. Drug-resistant MCF-7/ADR cells had higher sonoporation efficiency than drug-sensitive MCF-7 cells. The molecular subtype of tumors should be considered when sonoporation is applied, and optimal parameter combination may have the potential to improve drug-delivery efficiency by increasing the sonoporation efficiency.

Isoprostanoids quantitative profiling of marine red and brown macroalgae

With the increasing demand for direct human and animal consumption seaweed farming is rapidly expanding worldwide. Macroalgae have colonized aquatic environments in which they are submitted to frequent changes in biotic and abiotic factors that can trigger oxidative stress (OS). Considering that isoprostanoid derivatives may constitute the most relevant OS biomarkers, we were interested to establish their profile in two red and four brown macroalgae. Seven phytoprostanes, three phytofuranes, and four isoprostanes were quantified through a new micro-LC-MS/MS method. The isoprostanoid contents vary greatly among all the samples, the ent-16(RS)-9-epi-ST-Δ¹⁴-10-PhytoF and the sum of 5-F_2t-IsoP and 5-epi-5F_2t-IsoP being the major compounds for most of the macroalgae studied. We further quantified these isoprostanoids in macroalgae submitted to heavy metal (copper) exposure. In most of the cases, their concentrations increased after 24 h of copper stress corroborating the original hypothesis. One exception is the decrease of ent-9-L1-PhytoP content in L. digitata.

Sorting out the phytoprostane and phytofuran profile in vegetable oils

Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are prostaglandin-like compounds, contributing to defense signaling and prevention of cellular damage. These plant oxylipins result from autoxidation of α-linolenic acid (ALA) and have been proposed as new bioactive compounds due to their structural analogies with isoprostanes (IsoPs) and prostanoids derived from arachidonic acid in mammals, which have demonstrated diverse biological activities. The present work assesses a wide range of vegetable oils - including extra virgin olive oils (n = 7) and flax, sesame, argan, safflower seed, grapeseed, and palm oils - for their content of PhytoPs and PhytoFs. Flax oil displayed the highest concentrations, being notable the presence of 9-epi-9-D_1t-PhytoP, 9-D_1t-PhytoP, 16-B₁-PhytoP, and 9-L₁-PhytoP (7.54, 28.09, 28.67, and 19.22 μg mL^-1, respectively), which contributed to a total PhytoPs concentration of 119.15 μg mL^-1, and of ent-16-(RS)-9-epi-ST-Δ¹⁴-10-PhytoF (21.46 μg mL^-1). Palm and grapeseed oils appeared as the most appropriate negative controls, given the near absence of PhytoPs and PhytoFs (lower than 0.15 μg mL^-1). These data inform on the chance to develop nutritional trials using flax and grapeseed oils as food matrices that would provide practical information to design further assays intended to determine the actual bioavailability/bioactivity in vivo.

Comparative Study of the Phytoprostane and Phytofuran Content of indica and japonica Rice (Oryza sativa L.) Flours

Phytoprostanes and phytofurans (PhytoPs and PhytoFs, respectively) are nonenzymatic lipid peroxidation products derived from α-linolenic acid (C18:3 n-3), considered biomarkers of oxidative degradation in plant foods. The present work profiled these compounds in white and brown grain flours and rice bran from 14 rice cultivars of the subspecies indica and japonica by ultrahigh performance liquid chromatography coupled to electrospray ionization and triple quadrupole mass spectrometry. For PhytoPs, the average concentrations were higher in rice bran (0.01-9.35 ng g^-1) than in white and brown grain flours (0.01-1.17 ng g^-1). In addition, the evaluation of rice flours for the occurrence PhytoFs evidenced average values 1.77, 4.22, and 10.30 ng g^-1 dw in rice bran, brown grain flour, and white grain flour, respectively. A significant correlation was observed between total and individual compounds. The concentrations retrieved suggest rice bran as a valuable source of PhytoPs and PhytoFs that should be considered in further studies on bioavailability and bioactivity of such compounds.

Isoprostanes, neuroprostanes and phytoprostanes: An overview of 25years of research in chemistry and biology

Since the beginning of the 1990's diverse types of metabolites originating from polyunsaturated fatty acids, formed under autooxidative conditions were discovered. Known as prostaglandin isomers (or isoprostanoids) originating from arachidonic acid, neuroprostanes from docosahexaenoic acid, and phytoprostanes from α-linolenic acid proved to be prevalent in biology. The syntheses of these compounds by organic chemists and the development of sophisticated mass spectrometry methods has boosted our understanding of the isoprostanoid biology. In recent years, it has become accepted that these molecules not only serve as markers of oxidative damage but also exhibit a wide range of bioactivities. In addition, isoprostanoids have emerged as indicators of oxidative stress in humans and their environment. This review explores in detail the isoprostanoid chemistry and biology that has been achieved in the past three decades.

FRET-based method for evaluation of the efficiency of reversible and irreversible sonoporation

It is widely known that not all of the treated cells survive after introduction of exogenous molecules via any physical method. Therefore, it is important to develop methods that would allow simultaneous evaluation of both molecular delivery efficiency and cell viability. This study presents Förster resonance energy transfer (FRET)-based method that allows molecular transfer and cell viability evaluation in a single measurement by employing two common fluorescent dyes, namely, ethidium bromide and trypan blue. The method has been validated using cell sonoporation. The FRET-based method allows the efficiency evaluation of both reversible and irreversible sonoporation in a single experiment. Therefore, this method could be used to reduce time, labor, and material cost while improving the accuracy of evaluations.

Selective sensitiveness of mesenchymal stem cells to shock waves leads to anticancer effect in human cancer cell co-cultures

AIM

Mesenchymal stem cells (MSC) possess the distinctive feature of homing in on and engrafting into the tumor stroma making their therapeutic applications in cancer treatment very promising. Research into new effectors and external stimuli, which can selectively trigger the release of cytotoxic species from MSC toward the cancer cells, significantly raises their potential.

MAIN METHODS

Shock waves (SW) have recently gained recognition for their ability to induce specific biological effects, such as the local generation of cytotoxic reactive oxygen species (ROS) in a non-invasive and tunable manner. We thus investigate whether MSC are able to generate ROS and, in turn, affect cancer cell growth when in co-culture with human glioblastoma (U87) or osteosarcoma (U2OS) cells and exposed to SW.

KEY FINDINGS

MSC were found to be the cell line that was most sensitive to SW treatment as shown by SW-induced ROS production and cytotoxicity. Notably, U87 and U2OS cancer cell growth was unaffected by SW exposure. However, significant decreases in cancer cell growth, 1.8 fold for U87 and 2.3 fold for U2OS, were observed 24h after the SW treatment of MSC co-cultures with cancer cells. The ROS production induced in MSC by SW exposure was then responsible for lipid peroxidation and cell death in U87 and U2OS cells co-cultured with MSC.

SIGNIFICANCE

This experiment highlights the unique ability of MSC to generate ROS upon SW treatment and induce the cell death of co-cultured cancer cells. SW might therefore be proposed as an innovative tool for MSC-mediated cancer treatment.

Investigation of Microbubble Cavitation-Induced Calcein Release from Cells In Vitro

In the present study, microbubble (MB) cavitation signal analysis was performed together with calcein release evaluation in both pressure and exposure duration domains of the acoustic field. A passive cavitation detection system was used to simultaneously measure MB scattering and attenuation signals for subsequent extraction efficiency relative to MB cavitation activity. The results indicate that the decrease in the efficiency of extraction of calcein molecules from Chinese hamster ovary cells, as well as cell viability, is associated with MB cavitation activity and can be accurately predicted using inertial cavitation doses up to 0.18 V × s (R² > 0.9, p < 0.0001). No decrease in additional calcein release or cell viability was observed after complete MB sonodestruction was achieved. This indicates that the optimal exposure duration within which maximal sono-extraction efficiency is obtained coincides with the time necessary to achieve complete MB destruction. These results illustrate the importance of MB inertial cavitation in the sono-extraction process. To our knowledge, this study is the first to (i) investigate small molecule extraction from cells via sonoporation and (ii) relate the extraction process to the quantitative characteristics of MB cavitation acoustic spectra.

Thermal Stress in Melon Plants: Phytoprostanes and Phytofurans as Oxidative Stress Biomarkers and the Effect of Antioxidant Supplementation

The extreme temperatures generated in the melon crop, early harvest, induce an increase in reactive oxygen species (ROS) plant levels leading to oxidative stress. Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are plant metabolites derived from α-linolenic acid oxidation induced by ROS. The aims of this work were to evaluate PhytoPs and PhytoFs as oxidative stress biomarkers in leaves of melon plants thermally stressed. In addition, to fortify melon plant antioxidant defenses, foliar spraying was assayed using salicylic and gallic acid solutions and Ilex paraguariensis extract. PhytoP and PhytoF concentration ranges were 109-1146 and 130-4400 ng/g, respectively. Their levels in stressed plants were significantly higher than in nonstressed samples. In stressed samples treated with I. paraguariensis, PhytoP and PhytoF levels were significantly lower than in stressed samples without antioxidants. PhytoPs and PhytoFs represent relevant oxidative stress biomarkers in melon leaves. The use of natural antioxidants could reduce plant oxidative stress.

Assessment of Isoprostanes in Human Plasma: Technical Considerations and the Use of Mass Spectrometry

Oxygenated lipid mediators released from non-enzymatic peroxidation of polyunsaturated fatty acids (PUFA) are known to have functional roles in humans. Notably, among these lipid mediators, isoprostanes molecules are robust biomarkers of oxidative stress but those from n-3 PUFA are also bioactive molecules. In order to identify and assess the isoprostanes, the use of mass spectrometry (MS) for analysis is preferable and has been used for over two decades. Gas chromatography (GC) is commonly coupled to the MS to separate the derivatized isoprostanes of interest in biological samples. In order to increase the accuracy of the analytical performance, GC-MS/MS was also applied. Lately, MS or MS/MS has been coupled with high-performance liquid chromatography to assess multiple isoprostane molecules in a single biological sample without derivatization process. However, there are limitations for the use of LC-MS/MS in the measurement of plasma isoprostanes, which will be discussed in this review.

In vitro methods to study bubble-cell interactions: Fundamentals and therapeutic applications

Besides their use as contrast agents for ultrasound imaging, microbubbles are increasingly studied for a wide range of therapeutic applications. In particular, their ability to enhance the uptake of drugs through the permeabilization of tissues and cell membranes shows great promise. In order to fully understand the numerous paths by which bubbles can interact with cells and the even larger number of possible biological responses from the cells, thorough and extensive work is necessary. In this review, we consider the range of experimental techniques implemented in in vitro studies with the aim of elucidating these microbubble-cell interactions. First of all, the variety of cell types and cell models available are discussed, emphasizing the need for more and more complex models replicating in vivo conditions together with experimental challenges associated with this increased complexity. Second, the different types of stabilized microbubbles and more recently developed droplets and particles are presented, followed by their acoustic or optical excitation methods. Finally, the techniques exploited to study the microbubble-cell interactions are reviewed. These techniques operate over a wide range of timescales, or even off-line, revealing particular aspects or subsequent effects of these interactions. Therefore, knowledge obtained from several techniques must be combined to elucidate the underlying processes.

Non-enzymatic cyclic oxygenated metabolites of adrenic, docosahexaenoic, eicosapentaenoic and α-linolenic acids; bioactivities and potential use as biomarkers

Cyclic oxygenated metabolites are formed in vivo through non-enzymatic free radical reaction of n-6 and n-3 polyunsaturated fatty acids (PUFAs) such as arachidonic (ARA C20:4 n-6), adrenic (AdA 22:4 n-6), α-linolenic (ALA 18:3 n-3), eicosapentaenoic (EPA 20:5 n-3) and docosahexaenoic (DHA 22:6 n-3) acids. These cyclic compounds are known as isoprostanes, neuroprostanes, dihomo-isoprostanes and phytoprostanes. Evidence has emerged for their use as biomarkers of oxidative stress and, more recently, the n-3PUFA-derived compounds have been shown to mediate bioactivities as secondary messengers. Accordingly, this review will focus on the cyclic oxygenated metabolites generated from AdA, ALA, EPA and DHA. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Current development in non-enzymatic lipid peroxidation products, isoprostanoids and isofuranoids, in novel biological samples

Isoprostanoids and isofuranoids are lipid mediators that can be formed from omega-3 and omega-6 polyunsaturated fatty acids (PUFAs). F2-isoprostanes formed from arachidonic acid, especially 15-F2t-isoprostane, are commonly measured in biological tissues for decades as the biomarker for oxidative stress and diseases. Recently, other forms of isoprostanoids derived from adrenic, eicosapentaenoic, and docosahexaenoic acids namely F2-dihomo-isoprostanes, F3-isoprostanes, and F4-neuroprostanes respectively, and isofuranoids including isofurans, dihomo-isofurans, and neurofurans are reported as oxidative damage markers for different metabolisms. The most widely used samples in measuring lipid peroxidation products include but not limited to the blood and urine; other biological fluids, specialized tissues, and cells can also be determined. In this review, measurement of isoprostanoids and isofuranoids in novel biological samples by gas chromatography (GC)-mass spectrometry (MS), GC-MS/MS, liquid chromatography (LC)-MS, and LC-MS/MS will be discussed.

Non-enzymatic lipid oxidation products in biological systems: assessment of the metabolites from polyunsaturated fatty acids

Metabolites of non-enzymatic lipid peroxidation of polyunsaturated fatty acids notably omega-3 and omega-6 fatty acids have become important biomarkers of lipid products. Especially the arachidonic acid-derived F2-isoprostanes are the classic in vivo biomarker for oxidative stress in biological systems. In recent years other isoprostanes from eicosapentaenoic, docosahexaenoic, adrenic and α-linolenic acids have been evaluated, namely F3-isoprostanes, F4-neuroprostanes, F2-dihomo-isoprostanes and F1-phytoprostanes, respectively. These have been gaining interest as complementary specific biomarkers in human diseases. Refined extraction methods, robust analysis and elucidation of chemical structures have improved the sensitivity of detection in biological tissues and fluids. Previously the main reliable instrumentation for measurement was gas chromatography-mass spectrometry (GC-MS), but now the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunological techniques is gaining much attention. In this review, the types of prostanoids generated from non-enzymatic lipid peroxidation of some important omega-3 and omega-6 fatty acids and biological samples that have been determined by GC-MS and LC-MS/MS are discussed.