Clotrimazole enhances lysis of human erythrocytes induced by t-BHP

Seabra PS, Fonseca ADN, de Azevedo Sousa KM, de Oliveira SBB, Carneiro ADS, Coleman MD, Monteiro MC. Alpha-Lipoic Acid and Its Enantiomers Prevent Methemoglobin Formation and DNA Damage Induced by Dapsone Hydroxylamine: Molecular Mechanism and Antioxidant Action

Dapsone (DDS) therapy can frequently lead to hematological side effects, such as methemoglobinemia and DNA damage. In this study, we aim to evaluate the protective effect of racemic alpha lipoic acid (ALA) and its enantiomers on methemoglobin induction. The pre- and post-treatment of erythrocytes with ALA, ALA isomers, or MB (methylene blue), and treatment with DDS-NOH (apsone hydroxylamine) was performed to assess the protective and inhibiting effect on methemoglobin (MetHb) formation. Methemoglobin percentage and DNA damage caused by dapsone and its metabolites were also determined by the comet assay. We also evaluated oxidative parameters such as SOD, GSH, TEAC (Trolox equivalent antioxidant capacity) and MDA (malondialdehyde). In pretreatment, ALA showed the best protector effect in 2.5 µg/mL of DDS-NOH. ALA (1000 µM) was able to inhibit the induced MetHb formation even at the highest concentrations of DDS-NOH. All ALA tested concentrations (100 and 1000 µM) were able to inhibit ROS and CAT activity, and induced increases in GSH production. ALA also showed an effect on DNA damage induced by DDS-NOH (2.5 µg/mL). Both isomers were able to inhibit MetHb formation and the S-ALA was able to elevate GSH levels by stimulating the production of this antioxidant. In post-treatment with the R-ALA, this enantiomer inhibited MetHb formation and increased GSH levels. The pretreatment with R-ALA or S-ALA prevented the increase in SOD and decrease in TEAC, while R-ALA decreased the levels of MDA; and this pretreatment with R-ALA or S-ALA showed the effect of ALA enantiomers on DNA damage. These data show that ALA can be used in future therapies in patients who use dapsone chronically, including leprosy patients.

Blood cell-based drug delivery systems: a biomimetic platform for antibacterial therapy

With the rapid increase in multidrug-resistance against antibiotics, higher doses of antibiotics or more effective antibiotics are needed to treat diseases, which ultimately leads to a decrease in the body's immunity and seriously threatens human health worldwide. The efficiency of antibiotics has been a large challenge for years. To overcome this problem, many carriers are utilized for anti-bacteria, attempting to optimize the delivery of such drugs and transport them safely and directly to the site of disease. Blood cell-based drug delivery systems present several advantages as compared to polymeric delivery system. These blood cells including red blood cells (RBCs), leukocytes, platelets. The blood cells and their membranes can both be used as drug carriers to deliver antibacterial drugs. In addition, blood cells can overcome many physiological/pathological obstacles faced by nanoparticles in vivo and effectively deliver drugs to the site of the disease. In this paper, we review studies on blood cell-based delivery systems used in antibacterial therapy, and analyze different roles in antibacterial therapy, which provide basis for further study in this field.

Promising nanomaterials in the fight against malaria

For more than one hundred years, several treatments against malaria have been proposed but they have systematically failed, mainly due to the occurrence of drug resistance in part resulting from the exposure of the parasite to low drug doses. Several factors are behind this problem, including (i) the formidable barrier imposed by the Plasmodium life cycle with intracellular localization of parasites in hepatocytes and red blood cells, (ii) the adverse fluidic conditions encountered in the blood circulation that affect the interaction of molecular components with target cells, and (iii) the unfavorable physicochemical characteristics of most antimalarial drugs, which have an amphiphilic character and can be widely distributed into body tissues after administration and rapidly metabolized in the liver. To surpass these drawbacks, rather than focusing all efforts on discovering new drugs whose efficacy is quickly decreased by the parasite's evolution of resistance, the development of effective drug delivery carriers is a promising strategy. Nanomaterials have been investigated for their capacity to effectively deliver antimalarial drugs at local doses sufficiently high to kill the parasites and avoid drug resistance evolution, while maintaining a low overall dose to prevent undesirable toxic side effects. In recent years, several nanostructured systems such as liposomes, polymeric nanoparticles or dendrimers have been shown to be capable of improving the efficacy of antimalarial therapies. In this respect, nanomaterials are a promising drug delivery vehicle and can be used in therapeutic strategies designed to fight the parasite both in humans and in the mosquito vector of the disease. The chemical analyses of these nanomaterials are essential for the proposal and development of effective anti-malaria therapies. This review is intended to analyze the application of nanomaterials to improve the drug efficacy on different stages of the malaria parasites in both the human and mosquito hosts.

Mentha pulegium crude extracts induce thiol oxidation and potentiate hemolysis when associated to t-butyl hydroperoxide in human's erythrocytes

Mentha pulegium (Lamiaceae) tea has been used as a traditional medicine; however, the modulatory effect of M. pulegium extracts on damage to human erythrocytes associated to t-butyl hydroperoxide (t-BHP) exposure remains to be investigated. Accordingly, we perform this study in order to test the hypothesis that aqueous and ethanolic extracts of M. pulegium could modulate the hemolysis associated to t-BHP exposure, non-protein thiol (NPSH) oxidation and lipid peroxidation (measured as thiobarbituric acid reactive substances - TBARS) in human erythrocytes. Samples were co-incubated with t-BHP (4 mmol/L) and/or aqueous or ethanolic extracts (10-1000 mg/mL) during 120 min to further analysis. We found that both extracts, when associated to t-BHP, potentiate NPSH oxidation and hemolysis. Moreover, both extracts significantly prevents against t-BHP-induced TBARS production. A significant correlation among hemolysis and NPSH levels was found. Taking together, our data points that the association of M. pulegium extracts with t-BHP culminates in toxic effect to exposed erythrocytes, besides its protective effect against t-BHP-induced TBARS production. So, we infer that the use of this extract may exert negative effect during painful crisis in sickle cell anemia. However, more studies are still necessary to better investigate/understand the mechanism(s) involved in the toxic effect resultant from this association.

Macromolecular Conjugate and Biological Carrier Approaches for the Targeted Delivery of Antibiotics

For the past few decades, the rapid rise of antibiotic multidrug-resistance has presented a palpable threat to human health worldwide. Meanwhile, the number of novel antibiotics released to the market has been steadily declining. Therefore, it is imperative that we utilize innovative approaches for the development of antimicrobial therapies. This article will explore alternative strategies, namely drug conjugates and biological carriers for the targeted delivery of antibiotics, which are often eclipsed by their nanomedicine-based counterparts. A variety of macromolecules have been investigated as conjugate carriers, but only those most widely studied in the field of infectious diseases (e.g., proteins, peptides, antibodies) will be discussed in detail. For the latter group, blood cells, especially erythrocytes, have been successfully tested as homing carriers of antimicrobial agents. Bacteriophages have also been studied as a candidate for similar functions. Once these alternative strategies receive the amount of research interest and resources that would more accurately reflect their latent applicability, they will inevitably prove valuable in the perennial fight against antibiotic resistance.

In Vitro Protective Effect and Antioxidant Mechanism of Resveratrol Induced by Dapsone Hydroxylamine in Human Cells

Dapsone (DDS) hydroxylamine metabolites cause oxidative stress- linked adverse effects in patients, such as methemoglobin formation and DNA damage. This study evaluated the ameliorating effect of the antioxidant resveratrol (RSV) on DDS hydroxylamine (DDS-NHOH) mediated toxicity in vitro using human erythrocytes and lymphocytes. The antioxidant mechanism was also studied using in-silico methods. In addition, RSV provided intracellular protection by inhibiting DNA damage in human lymphocytes induced by DDS-NHOH. However, whilst pretreatment with RSV (10-1000 μM significantly attenuated DDS-NHOH-induced methemoglobinemia, but it was not only significantly less effective than methylene blue (MET), but also post-treatment with RSV did not reverse methemoglobin formation, contrarily to that observed with MET. DDS-NHOH inhibited catalase (CAT) activity and reactive oxygen species (ROS) generation, but did not alter superoxide dismutase (SOD) activity in erythrocytes. Pretreatment with RSV did not alter these antioxidant enzymes activities in erythrocytes treated with DDS-NHOH. Theoretical calculations using density functional theory methods showed that DDS-NHOH has a pro-oxidant effect, whereas RSV and MET have antioxidant effect on ROS. The effect on methemoglobinemia reversion for MET was significantly higher than that of RSV. These data suggest that the pretreatment with resveratrol may decrease heme-iron oxidation and DNA damage through reduction of ROS generated in cells during DDS therapy.

Delivery of drugs bound to erythrocytes: new avenues for an old intravascular carrier

For several decades, researchers have used erythrocytes for drug delivery of a wide variety of therapeutics in order to improve their pharmacokinetics, biodistribution, controlled release and pharmacodynamics. Approaches include encapsulation of drugs within erythrocytes, as well as coupling of drugs onto the red cell surface. This review focuses on the latter approach, and examines the delivery of red blood cell (RBC)-surface-bound anti-inflammatory, anti-thrombotic and anti-microbial agents, as well as RBC carriage of nanoparticles. Herein, we discuss the progress that has been made in surface loading approaches, and address in depth the issues relevant to surface loading of RBC, including intrinsic features of erythrocyte membranes, immune considerations, potential surface targets and techniques for the production of affinity ligands.

Effects of oxidative stress on red blood cell rheology in sickle cell patients

Sickle cell anaemia (SS) and sickle cell-haemoglobin C disease (SC) patients exhibit severe red blood cell (RBC) rheological alterations involved in the development of several complications. The contribution of oxidative stress in these haemorheological abnormalities is still unknown. We compared RBC reactive oxygen species (ROS) and glutathione (GSH) content, and the haemorheological profile of SS (n = 11), SC (n = 11) and healthy subjects (n = 12) at baseline and after in-vitro treatment with t-butyl hydroperoxide (TBHP). We showed: (i) higher RBC ROS content in SS and SC patients, with the highest level observed in SS patients; (ii) lower RBC GSH content in sickle syndrome patients, especially in SS patients; (iii) TBHP increased RBC ROS production and decreased RBC GSH content in all groups; (iv) TBHP decreased RBC aggregation and increased the strength of RBC aggregates in all groups but the increase in RBC aggregates strength was greater in sickle cell patients; (v) TBHP decreased RBC deformability in the three groups but with a higher magnitude in sickle cell patients. These data suggest that RBCs from sickle cell patients have an exaggerated response to oxidative stress, which is accompanied by a profound abnormal haemorheological profile, with greater alterations in SS than in SC patients.

Reinvestigation of drugs and chemicals as aquaporin-1 inhibitors using pressure-induced hemolysis in human erythrocytes

Recently, we have found that pressure-induced hemolysis is enhanced by inhibiting water transport via aquaporin-1 (AQP1), as seen in p-chloromercuribenzoate (pCMB)-treated erythrocytes. So, using this method we reinvestigated the functions as AQP1 inhibitors of drugs and chemicals such as acetazolamide, sodium nitroprusside, tetraethylammonium ions (TEA(+)), and dimethylsulfoxide (DMSO). The values of hemolysis at 200 MPa were almost unaffected by acetazolamide or sodium nitroprusside, decreased by TEA(+), and increased significantly by DMSO. Furthermore, the erythrocytes were exposed to pCMB in the presence of TEA(+) or DMSO. The enhancement effect of pCMB on pressure-induced hemolysis was unaffected by TEA(+) but attenuated by DMSO. Taken together, these results suggest that, of drugs and chemicals examined here, DMSO only is an AQP1 inhibitor, but the effect of DMSO is small compared with pCMB.

The sphingolipid degradation product trans-2-hexadecenal induces cytoskeletal reorganization and apoptosis in a JNK-dependent manner

The bioactive signaling molecule D-erythro-sphingosine-1-phosphate (S1P) is irreversibly degraded by the enzyme S1P lyase (SPL). The reaction of SPL with C18-S1P generates ethanolamine phosphate and a long-chain fatty aldehyde, trans-2-hexadecenal. Modulation of SPL expression in cells and organisms produces significant phenotypes, most of which have been attributed to corresponding changes in S1P-dependent signaling. However, the physiological functions of SPL products are not well understood. In the present study, we explored the biological activities of trans-2-hexadecenal in human and murine cells. We demonstrate that trans-2-hexadecenal causes cytoskeletal reorganization leading to cell rounding, detachment and eventual cell death by apoptosis in multiple cell types, including HEK293T, NIH3T3 and HeLa cells. Trans-2-hexadecenal stimulated a signaling pathway involving MLK3 and the respective phosphorylation of MKK4/7 and JNK, whereas ERK, AKT and p38 were unaffected. Trans-2-hexadecenal-induced apoptosis was accompanied by activation of downstream targets of JNK including c-Jun phosphorylation, cytochrome c release, Bax activation, Bid cleavage and increased translocation of Bim into mitochondria. The antioxidant N-acetylcysteine prevented JNK activation by trans-2-hexadecenal. Further, inhibition of JNK abrogated the cytoskeletal changes and apoptosis caused by trans-2-hexadecenal, whereas Rac1 and RhoA were not involved. In conclusion, our studies provide a new paradigm of sphingolipid signaling by demonstrating for the first time that S1P metabolism generates a bioactive product that induces cellular effects through oxidant stress-dependent MAP kinase cell signaling.

Protective effect of desloratadine against oxidative stress in human erythrocytes in vitro

Desloratadine (DCL) is a non-sedating antihistamine approved for the treatment of allergic rhinitis or chronic idiopathic urticaria. The objective of this study was to evaluate the potential protective effect of DCL against oxidative stress in human erythrocytes in vitro. Human erythrocytes were oxidized by a water-soluble radical generators-2,2' azobis (2-amidinopropane) hydrochloride (AAPH; 20, 50mM) or tert-butyl hydroperoxide (TBHP; 0.5mM) and the protective effects of DCL (2, 5, 7, 10 and 26μM) on selected oxidative stress markers were investigated. Erythrocytes were divided into aliquots. The first aliquot was incubated for 2h at 37°C with AAPH or TBHP. The other test aliquots were preincubated with selected concentrations of DCL for 30min and followed by AAPH or TBHP incubation for 2h. Malondialdehyde (MDA) content, catalase (CAT) and superoxide dismutase (SOD) activities, as well as hemolysis percentage (H) were measured in all erythrocyte samples. The influence of solvent (0.5% ethanol) on the parameters studied was also checked. Pretreatment with DCL (7, 10, 26μM) could prevent TBHP-induced increase in MDA formation in a concentration-dependent manner. DCL has no influence on CAT activity and it significantly enhanced SOD activity compared to AAPH treatment samples at 7, 10, 26μM. DCL (26μM) also reduced the hemolytic effect on erythrocytes when compared to the erythrocytes exposed to oxidants only. These results suggest a beneficial effect of DCL as an antioxidant, which might be an additional explanation of its therapeutic action.

Drug delivery by red blood cells: vascular carriers designed by mother nature

IMPORTANCE OF THE FIELD

Vascular delivery of several classes of therapeutic agents may benefit from carriage by red blood cells (RBC), for example, drugs that require delivery into phagocytic cells and those that must act within the vascular lumen. The fact that several protocols of infusion of RBC-encapsulated drugs are now being explored in patients illustrates a high biomedical importance for the field. AREAS COVERED BY THIS REVIEW: Two strategies for RBC drug delivery are discussed: encapsulation into isolated RBC ex vivo followed by infusion in compatible recipients and coupling therapeutics to the surface of RBC. Studies of pharmacokinetics and effects in animal models and in human studies of diverse therapeutic enzymes, antibiotics and other drugs encapsulated in RBC are described and critically analyzed. Coupling to RBC surface of compounds regulating immune response and complement, affinity ligands, polyethylene glycol alleviating immune response to donor RBC and fibrinolytic plasminogen activators are described. Also described is a new, translation-prone approach for RBC drug delivery by injection of therapeutics conjugated with fragments of antibodies providing safe anchoring of cargoes to circulating RBC, without need for ex vivo modification and infusion of RBC.

WHAT THE READER WILL GAIN

Readers will gain historical perspective, current status, challenges and perspectives of medical applications of RBC for drug delivery.

TAKE HOME MESSAGE

RBC represent naturally designed carriers for intravascular drug delivery, characterized by unique longevity in the bloodstream, biocompatibility and safe physiological mechanisms for metabolism. New approaches for encapsulating drugs into RBC and coupling to RBC surface provide promising avenues for safe and widely useful improvement of drug delivery in the vascular system.