Nitric Oxide Donor Research Articles

Photorelease of Nitric Oxide (NO) in Mono- and Bimetallic Ruthenium Nitrosyl Complexes: A Photokinetic Investigation with a Two-Step Model.

Two monometallic and three bimetallic ruthenium acetonitrile (RuMeCN) complexes are presented and fully characterized. All of them are built from the same skeleton [FTRu(bpy)(MeCN)]2+, in which FT is a fluorenyl-substituted terpyridine ligand and bpy is the 2,2'-bipyridine. The crystal structure of [FTRu(bpy)(MeCN)](PF6)2 is presented. A careful spectroscopic analysis allows establishing that these 5 RuMeCN complexes can be identified as the product of the photoreaction of 5 related RuNO complexes, investigated as efficient nitric oxide (NO) donors. Based on this set of complexes, the mechanism of the NO photorelease of the bimetallic complexes has been established through a complete investigation under irradiations performed at 365, 400, 455, and 490 nm wavelength. A two-step (A → B → C) kinetic model specially designed for this purpose provides a good description of the mechanism, with quantum yields of photorelease in the range 0.001-0.029, depending on the irradiation wavelength. In the first step of release, the quantum yields (ϕAB) are always found to be larger than those of the second step (ϕBC), at any irradiation wavelengths.

Nitric oxide and mitochondria injuries in kidney tissue upon a simulation of cardiopulmonary bypass and circulatory arrest: an experimental study

Introduction: Surgical interventions under cardiopulmonary bypass and circulatory arrest are complicated by impaired microcirculation in tissues; during hypoxic period the mitochondria dysfunction becomes the leading pathogenetic factor of ischemia-reperfusion injuries. In this regard, the search for methods of organ protection seems to be an extremely urgent task. The using of nitric oxide can be a promising technique given its pluripotent properties.Objective: The study was aimed to examining of mitochondria injuries in kidney biopsies stipulated by cardiopulmonary bypass and circulatory arrest when simulating cardiac surgery, as well as to assessing the potentials of organ protection with nitric oxide in the experiment.Methods: The study was carried out on Altai breed sheep and included simulating of cardiopulmonary bypass and circulatory arrest. The first group (n = 6) was provided with intraoperative nitric oxide donation. The second group (n = 6) served as a control (without nitric oxide donation). Mitochondria injuries were assessed in kidney biopsies by measuring transmembrane potential and Ca2+-binding capacity of organelles, as well as by determining ATP and lactate concentrations.Results: Nitric oxide therapy was associated with less mitochondria dysfunction in kidney biopsies compared with the control group. There was a steady trend to the amelioration of the energy maintenance in the renal parenchyma in the nitric oxide donation group.Conclusion: A steady trend towards optimizing the energy supply of tissues under cardiopulmonary bypass and circulatory arrest was revealed in an experiment against the background of NO donation at a concentration of 80 ppm. Received 11 February 2024. Revised 28 March 2024. Accepted 29 March 2024. Funding: The The study was carried out within the framework of the state assignment “Protection of organs by nitric oxide in cardiovascular surgery: technological support (synthesis and delivery devices), mechanisms for implementing protective effects and impact on clinical outcomes” (topic No. 122123000017-3). Conflict of interest: The authors declare no conflict of interest. Contribution of the authors Conception and study design: A.M. Boyko, N.O. Kamenshchikov, Yu.K. Podoksenov, L.N. Maslov, B.N. Kozlov Data collection and analysis: A.M. Boyko, Yu.S. Svirko, V.A. Lugovskiy, A.V. Mukhomedzyanov, B.A. BazarbekovaStatistical analysis: I.V. KravchenkoDrafting the article: A.M. Boyko Critical revision of the article: N.O. Kamenshchikov, A.G. Miroshnichenko, Yu.K. Podoksenov, M.L. Diakova, K.A. Petlin, D.S. Panfilov, B.N. KozlovFinal approval of the version to be published: A.M. Boyko, N.O. Kamenshchikov, A.G. Miroshnichenko, Yu.K. Podoksenov, Yu.S. Svirko, V.A. Lugovskiy, M.L. Diakova, I.V. Kravchenko, A.V. Mukhomedzyanov, L.N. Maslov, B.A. Bazarbekova, K.A. Petlin, D.S. Panfilov, B.N. Kozlov

In Vivo Assessment of Dual-Function Submicron Textured Nitric Oxide Releasing Catheters in a 7-Day Rabbit Model

Catheter-induced thrombosis is a major contributor to infectious and mechanical complications of biomaterials that lead to device failure. Herein, a dual functional submicron textured nitric oxide (NO)-releasing catheter was developed. The hemocompatibility and antithrombotic activity of vascular catheters were evaluated in both 20 h in vitro blood loop and 7 d in vivo rabbit model. Surface characterization assessments via atomic force microscopy show the durability of the submicron pattern after incorporation of NO donor S-nitroso-N-acetylpenicillamine (SNAP). The SNAP-doped catheters exhibited prolonged and controlled NO release mimicking the levels released by endothelium. Fabricated catheters showed cytocompatibility when evaluated against BJ human fibroblast cell lines. After 20h in vitro evaluation of catheters in a blood loop, textured-NO catheters exhibited a 13-times reduction in surface thrombus formation compared to the control catheters, which had 83% of the total area covered by clots. After the 7 d in vivo rabbit model, analysis on the catheter surface was examined via scanning electron microscopy, where significant reduction of platelet adhesion, fibrin mesh, and thrombi can be observed on the NO-releasing textured surfaces. Moreover, compared to relative controls, a 63% reduction in the degree of thrombus formation within the jugular vein was observed. Decreased levels of fibrotic tissue decomposition on the jugular vein and reduced platelet adhesion and thrombus formation on the texture of the NO-releasing catheter surface are indications of mitigated foreign body response. This study demonstrated a biocompatible and robust dual-functioning textured NO PU catheter in limiting fouling-induced complications for longer-term blood-contacting device applications. Statement of SignificanceCatheter-induced thrombosis is a major contributor to infectious and mechanical complications of biomaterials that lead to device failure. This study demonstrated a robust, biocompatible, dual-functioning textured nitric oxide (NO) polyurethane catheter in limiting fouling-induced complications for longer-term blood-contacting device applications.The fabricated catheters exhibited prolonged and controlled NO release that mimics endothelium levels. After the 7 d in vivo model, a significant reduction in platelet adhesion, fibrin mesh, and thrombi was observed on the NO-releasing textured catheters, along with decreased levels of fibrotic tissue decomposition on the jugular vein. Results illustrate that NO-textured catheter surface mitigates foreign body response.

Engineering Nitric Oxide-Releasing Antimicrobial Dental Coating for Targeted Gingival Therapy.

Bacterial biofilms play a central role in the development and progression of periodontitis, a chronic inflammatory condition that affects the oral cavity. One solution to current treatment constraints is using nitric oxide (NO)─with inherent antimicrobial properties. In this study, an antimicrobial coating is developed from the NO donor S-nitroso-N-acetylpenicillamine (SNAP) embedded within polyethylene glycol (PEG) to prevent periodontitis. The SNAP-PEG coating design enabled a controlled NO release, achieving tunable NO levels for more than 24 h. Testing the SNAP-PEG composite on dental floss showed its effectiveness as a uniform and bioactive coating. The coating exhibited antibacterial properties against Streptococcus mutans and Escherichia coli, with inhibition zones measuring up to 7.50 ± 0.28 and 14.80 ± 0.46 mm2, respectively. Furthermore, SNAP-PEG coating materials were found to be stable when stored at room temperature, with 93.65% of SNAP remaining after 28 d. The coatings were biocompatible against HGF and hFOB 1.19 cells through a 24 h controlled release study. This study presents a facile method to utilize controlled NO release with dental antimicrobial coatings comprising SNAP-PEG. This coating can be easily applied to various substrates, providing a user-friendly approach for targeted self-care in managing gingival infections associated with periodontitis.

A Crucial Role of Proteolysis in the Formation of Intracellular Dinitrosyl Iron Complexes.

Dinitrosyl iron complexes (DNICs) stabilize nitric oxide in cells and tissues and constitute an important form of its storage and transportation. DNICs may comprise low-molecular-weight ligands, e.g., thiols, imidazole groups in chemical compounds with low molecular weight (LMWDNICs), or high-molecular-weight ligands, e.g., peptides or proteins (HMWDNICs). The aim of this study was to investigate the role of low- and high-molecular-weight ligands in DNIC formation. Lysosomal and proteasomal proteolysis was inhibited by specific inhibitors. Experiments were conducted on human erythroid K562 cells and on K562 cells overexpressing a heavy chain of ferritin. Cell cultures were treated with •NO donor. DNIC formation was monitored by electron paramagnetic resonance. Pretreatment of cells with proteolysis inhibitors diminished the intensity and changed the shape of the DNIC-specific EPR signal in a treatment time-dependent manner. The level of DNIC formation was significantly influenced by the presence of protein degradation products. Interestingly, formation of HMWDNICs depended on the availability of LMWDNICs. The extent of glutathione involvement in the in vivo formation of DNICs is minor yet noticeable, aligning with our prior research findings.

Tumor microenvironment reprogramming combined with immunogenic enhancement by nanoemulsions potentiates immunotherapy

The combination of immune checkpoint inhibitors and immunogenic cell death (ICD) inducers has become a promising strategy for the treatment of various cancers. However, its efficacy remains unmet because of the dense stroma and defective vasculatures in the tumor microenvironment (TME) that restricts the intratumoral infiltration of cytotoxic T lymphocytes (CTLs). Herein, cancer-associated fibroblasts (CAFs)-targeted nanoemulsions are tailored to combine the ICD induction and the TME reprogramming to sensitize checkpoint blockade immunotherapy. Melittin, as an ICD inducer and an antifibrotic agent, is efficiently encapsulated into the nanoemulsion accompanied by a nitric oxide donor to improve its bioavailability and tumor targeting. The nanoemulsions exhibited dual functionality by directly inducing direct cancer cell death and enhancing the tumoral immunogenicity, while also synergistically reprogramming the TME through reversing the activated CAFs, decreasing collagen deposition and restoring tumor vessels. Consequently, these nanemulsions successfully facilitated the CTLs infiltration and suppressing the recruitment of immunosuppressive cells. A combination of AE-MGNPs and anti-CTLA-4 antibody greatly elicited a striking level of antitumor T-cell response to suppress tumor growth in CAFs-rich colorectal tumor models. Our work emphasized the integration of the ICD induction with simultaneous modulation of the TME to enhance the sensitivity of patients to checkpoint blockade immunotherapy.

Targeted delivery of NO donor and ROS scavenger for synergistic treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by high level of reactive oxygen species (ROS) and proinflammatory cytokines, which facilitate the activation of the inflammatory signaling such as NF-κB pathway and exacerbate the development of inflammation. Herein, we designed a nanodrug by encapsulating the NO donor S-nitrosoglutathione (GSNO) into an emulsion and coating the surface with a polydopamine (PDA) layer to yield GSNO@PDA, which simultaneously scavenged the extra ROS and suppressed NF-κB signaling for potent RA treatment. To enhance the cellular uptake and NO generation efficiency, dextran sulfate (DS) and Cu2+ were anchored on the surface of GSNO@PDA to obtain the final formulation GSNO@PDA@DS. Our results demonstrated that GSNO@PDA@DS were successfully prepared and the modification of DS effectively boosted the cellular uptake of GSNO@PDA@DS. Moreover, GSNO@PDA@DS lowered cellular ROS and elevated intracellular NO, resulting in a decrease of M1 phenotype, inhibition of NF-κB pathway and down-regulation of proinflammatory cytokine tumor necrosis factor-α (TNF-α). Further in vivo studies confirmed that GSNO@PDA@DS significantly relieved symptoms and bone erosion by regulating the microenvironment of RA, highlighting the potential of GSNO@PDA@DS for RA therapy through ROS scavenging and NO-mediated suppression of inflammatory signaling.

Pectin nanoparticles loaded with nitric oxide donor drug: A potential approach for tissue regeneration

The process of wound healing and tissue regeneration involves several key mechanisms to ensure the production of new tissues with similar cellular functions. This study investigates the impact of pectin, a natural polysaccharide, and nebivolol hydrochloride (NBV), a nitric oxide (NO) donor drug, on wound healing. Utilizing ionotropic gelation, NBV-loaded pectin nanoparticles were developed following a 2231 full factorial design. The optimized formulation, determined using Design expert® software, exhibited an encapsulation efficiency percentage of 70.68%, zeta potential of −51.4 mV, and a particle size of 572 nm, characterized by a spherical, discrete morphology. An in vivo study was conducted to evaluate the effectiveness of the optimal formulation in wound healing compared to various controls. The results demonstrated the enhanced ability of the optimal formulation to accelerate wound healing. Moreover, histopathological examination further confirmed the formulation's benefits in tissue proliferation and collagen deposition at the wound site 15 days post-injury. This suggests that the developed formulation not only promotes faster healing but does so with minimal side effects, positioning it as a promising agent for effective wound healing and tissue regeneration.

Pre-exercise nitric oxide donor supplementation attenuates decline in muscle contractile force and ryanodine receptor proteolysis following eccentric contraction

Pre-exercise nitric oxide donor supplementation attenuates decline in muscle contractile force and ryanodine receptor proteolysis following eccentric contraction

Emerging nitric oxide gas‐assisted cancer photothermal treatment

AbstractPhotothermal therapy (PTT) has garnered significant attention in recent years, but the standalone application of PTT still faces limitations that hinder its ability to achieve optimal therapeutic outcomes. Nitric oxide (NO), being one of the most extensively studied gaseous molecules, presents itself as a promising complementary candidate for PTT. In response, various nanosystems have been developed to enable the simultaneous utilization of PTT and NO‐mediated gas therapy (GT), with the integration of photothermal agents (PTAs) and thermally‐sensitive NO donors being the prevailing approach. This combination seeks to leverage the synergistic effects of PTT and GT while mitigating the potential risks associated with gas toxicity through the use of a single laser irradiation. Furthermore, additional internal or external stimuli have been employed to trigger NO release when combined with different types of PTAs, thereby further enhancing therapeutic efficacy. This comprehensive review aims to summarize recent advancements in NO gas‐assisted cancer photothermal treatment. It commences by providing an overview of various types of NO donors and precursors, including those sensitive to photothermal, light, ultrasound, reactive oxygen species, and glutathione. These NO donors and precursors are discussed in the context of dual‐modal PTT/GT. Subsequently, the incorporation of other treatment modalities such as chemotherapy (CHT), photodynamic therapy (PDT), alkyl radical therapy, radiation therapy, and immunotherapy (IT) in the creation of triple‐modal therapeutic nanoplatforms is presented. The review further explores tetra‐modal therapies, such as PTT/GT/CHT/PDT, PTT/GT/CHT/chemodynamic therapy (CDT), PTT/GT/PDT/IT, PTT/GT/starvation therapy (ST)/IT, PTT/GT/Ca2+ overload/IT, PTT/GT/ferroptosis (FT)/IT, and PTT/GT/CDT/IT. Finally, potential challenges and future perspectives concerning these novel paradigms are discussed. This comprehensive review is anticipated to serve as a valuable resource for future studies focused on the development of innovative photothermal/NO‐based cancer nanotheranostics.

Activation of mitoKATP channels induces penile vasodilation and inhibits mitochondrial respiration and ROS production: Role of NO

ObjectiveMitochondrial ATP-sensitive K+ (mitoKATP) channels are involved in neuronal and cardiac protection from ischemia and oxidative stress. Penile erection is a neurovascular event mediated by relaxation of the erectile tissue via nitric oxide (NO) released from nerves and endothelium. In the present study, we investigated whether mitoKATP channels play a role in the control of penile vascular tone and mitochondrial dynamics, and the involvement of NO. MethodsThe effect of the selective mitoKATP activator BMS191095 was examined on vascular tone, on mitochondrial bioenergetics by real-time measurements with Agilent Seahorse and on ROS production by MitoSOX fluorescence in freshly isolated microarteries. ResultsBMS191095 and diazoxide relaxed penile arteries, BMS191095 being one order of magnitude more potent. BMS191095-induced relaxations were reduced by mechanical endothelium removal and by inhibitors of the nitric oxide synthase (NOS) and PI3K enzymes. The NO-dependent component of the relaxation to BMS191095 was impaired in penile arteries from insulin resistant obese rats. The blockers of mitoKATP channel 5-HD, sarcolemma KATP (sarcKATP) channel glibenclamide, and large conductance Ca2+-activated K+ (BKCa) channel iberiotoxin, inhibited relaxations to BMS191095 and to the NO donor SNAP. BMS191095 reduced the mitochondrial bioenergetic profile of penile arteries and attenuated mitochondrial ROS production. Blockade of endogenous NO impaired and exogenous NO mimicked, respectively, the inhibitory effects of BMS191095 on basal respiration and oxygen consumed for ATP synthesis. Exogenous NO exhibited dual inhibitory/stimulatory effects on mitochondrial respiration. ConclusionsThese results demonstrate that selective activation of mitoKATP channels causes penile vasodilation, attenuates ROS production and inhibits mitochondrial respiration in part by releasing endothelial NO. These mechanisms couple blood flow and metabolism in penile arterial wall and suggest that activation of vascular mitoKATP channels may protect erectile tissue against ischemic injury.

THE ADVANTAGES OF SYDNONIMINES COMPARED TO NITRATES IN THE TREATMENT OF PATIENTS WITH ISCHEMIC HEART DISEASE AND CORONARY INSUFFICIENCY

One of the primary challenges in treating patients with coronary artery disease and coronary insufficiency using nitrates is the development of tolerance. Nitrate tolerance is a condition in which the duration and intensity of anti-anginal and anti-ischemic effects decrease, despite maintaining a high concentration of the drug in the blood. In cases of developing tolerance, a continual increase in the nitrate dose is necessary to achieve the previous effect. To eliminate developed nitrate tolerance, discontinuing nitrates for 3-5 days is typically sufficient. Currently, molsidomine is employed as an alternative to nitrates, with sydnonimines emerging as a noteworthy substitute. Among sydnonimines, molsidomine (marketed as Sydnopharm, Dilasidom, Corvaton) stands out as the most effective. Despite its chemical distinction from nitrates, molsidomine operates through a similar mechanism. Functioning as a nitric oxide donor, this antianginal drug avoids the development of tolerance even with prolonged use. Molsidomine, akin to nitrates, acts as a vasodilator, exhibiting efficacy as an anti-ischemic and anti-anginal medication when administered in appropriate doses. Upon entering the human body, molsidomine undergoes hepatic metabolism, transforming into an active derivative compound known as SIN-1. This metabolite, upon entering the bloodstream, further converts into an active form (SIN-1A). From this active metabolite, the nitric oxide (NO) group is released, influencing the activation of guanylate cyclase. This activation prompts guanosine triphosphate to convert into cyclic guanosine triphosphate, ultimately contributing to the synthesis of proteins that bind calcium. This cascade of events results in the vasodilatory effect of molsidomine. Indications for molsidomine include stable angina pectoris, acute coronary syndrome, early post-infarction angina, congestive heart failure, portal hypertension, pulmonary hypertension, and Aerz's disease. Possible side effects following the therapy with molsidomine (dizziness, headache, and diplopia) occur much less frequently compared to nitrates. After using nitrates, such a side effect as methemoglobinемia may occur. Therapy with molsidomine does not lead to the development of this side effect.

Bifunctional Sildenafil Diazeniumdiolates Acting as Phosphodiesterase 5 Inhibitors and Nitric Oxide Donors- Towards Wound Healing.

Inefficient wound healing poses a global health challenge with a lack of efficient treatments. Wound healing issues often correlate with low endogenous nitric oxide (NO) levels. While exogenous delivery with NO-releasing compounds represents a promising therapeutic strategy, controlling the release of the highly reactive NO remains challenging. Phosphodiesterase 5 (PDE5) inhibitors, like sildenafil, have also been shown to promote wound healing. This study explores hybrid compounds, combining NO-releasing diazeniumdiolates with a sildenafil-derived PDE5 inhibitor. One compound demonstrated a favorable NO-release profile, triggered by an esterase (prodrug), and displayed in vitro nanomolar inhibition potency against PDE5 and thrombin-induced platelet aggregation. Both factors are known to promote blood flow and oxygenation. Thus, our findings unveil promising prospects for effective wound healing treatments.

Dual-Responsive Supramolecular Polymeric Nanomedicine for Self-Cascade Amplified Cancer Immunotherapy.

Insufficient tumor immunogenicity and immune escape from tumors remain common problems in all tumor immunotherapies. Recent studies have shown that pyroptosis, a form of programmed cell death that is accompanied by immune checkpoint inhibitors, can induce effective immunogenic cell death and long-term immune activation. Therapeutic strategies to jointly induce pyroptosis and reverse immunosuppressive tumor microenvironments are promising for cancer immunotherapy. In this regard, a dual-responsive supramolecular polymeric nanomedicine (NCSNPs) to self-cascade amplify the benefits of cancer immunotherapy is designed. The NCSNPs are formulated by β-cyclodextrin coupling nitric oxide (NO) donor, a pyroptosis activator, and NLG919, an indoleamine 2,3-dioxygenase (IDO) inhibitor, and self-assembled through host-guest molecular recognition and hydrophobic interaction to obtain nanoparticles. NCSNPs possess excellent tumor accumulation and bioavailability attributed to ingenious supramolecular engineering. The study not only confirms the occurrence of NO-triggered pyroptosis in tumors for the first time but also reverses the immunosuppressive microenvironment in tumor sites via an IDO inhibitor by enhancing the infiltration of cytotoxic T lymphocytes, to achieve remarkable inhibition of tumor proliferation. Thus, this study provides a novel strategy for cancer immunotherapy.

Novel nitric oxide donors are coronary vasodilators that also bind to the papain-like protease of SARS-CoV-2

Several investigational nitric oxide donors were originally created to correct vascular endothelial dysfunction in cardiovascular diseases. These 48 compounds contain an urea-like moiety attached to the well-known NO donors isosorbide 2- and 5-mononitrate. CR-0305 and CR-0202 were synthesized and found to be nontoxic in the cell lines HMEC-1, A549/hACE2 and VeroE6. CR-0305 induced vasodilation in human coronary arteries ex vivo. Since NO can also have antiviral properties, a study of drug-protein interactions with SARS-CoV-2 was undertaken using in silico modeling. CR-0305 experimentally outperformed the other compounds, including CR-0202, in binding the catalytic site of SARS-CoV-2 papain-like protease (PLpro). PLpro is a primary target for therapeutic inhibition of SARS-CoV-2 as it mediates viral replication and modulates host innate immune responses. CR-0305 is predicted to sit firmly in the PLpro catalytic pocket as confirmed by molecular dynamics simulations, wherein stability of binding to the catalytic site of PLpro induces a conformational change in the BL2 loop to a more closed conformation as observed previously with GRL0617. Surface plasmon resonance was performed with CR-0305 and CR-0202 to characterize binding affinity to purified SARS-CoV-2 PLpro protein. CR-0305 and CR-0202 also inhibited SARS-CoV-2 infection compared to vehicle as measured by virus N protein staining with a specific antibody in A549-ACE2 and VeroE6 cells at 20 µM. CR-0305 is a coronary vasodilator that appears to bind to the catalytic site of the PLpro of SARS-CoV-2 while targeting delivery of antiviral NO to cells infected by SARS-CoV-2, suggesting multiple indications for future development.

Bioinspired superhydrophobic surfaces with silver and nitric oxide-releasing capabilities to prevent device-associated infections and thrombosis

Bacteria-associated infections and thrombus formation are the two major complications plaguing the application of blood-contacting medical devices. Therefore, functionalized surfaces and drug delivery for passive and active antifouling strategies have been employed. Herein, we report the novel integration of bio-inspired superhydrophobicity with nitric oxide release to obtain a functional polymeric material with anti-thrombogenic and antimicrobial characteristics. The nitric oxide release acts as an antimicrobial agent and platelet inhibitor, while the superhydrophobic components prevent non-specific biofouling. Widely used medical-grade silicone rubber (SR) substrates that are known to be susceptible to biofilm and thrombus formation were dip-coated with fluorinated silicon dioxide (SiO2) and silver (Ag) nanoparticles (NPs) using an adhesive polymer as a binder. Thereafter, the resulting superhydrophobic (SH) SR substrates were impregnated with S-nitroso-N-acetylpenicillamine (SNAP, an NO donor) to obtain a superhydrophobic, Ag-bound, NO-releasing (SH-SiAgNO) surface. The SH-SiAgNO surfaces had the lowest amount of viable adhered E. coli (> 99.9 % reduction), S. aureus (> 99.8 % reduction), and platelets (> 96.1 % reduction) as compared to controls while demonstrating no cytotoxic effects on fibroblast cells. Thus, this innovative approach is the first to combine SNAP with an antifouling SH polymer surface that possesses the immense potential to minimize medical device-associated complications without using conventional systemic anticoagulation and antibiotic treatments.

Nitric oxide nano-reactor DNMF/PLGA enables tumor vascular microenvironment and chemo-hyperthermia synergetic therapy

BackgroundBreast cancer ranks first among malignant tumors, of which triple-negative breast cancer (TNBC) is characterized by its highly invasive behavior and the worst prognosis. Timely diagnosis and precise treatment of TNBC are substantially challenging. Abnormal tumor vessels play a crucial role in TNBC progression and treatment. Nitric oxide (NO) regulates angiogenesis and maintains vascular homeostasis, while effective NO delivery can normalize the tumor vasculature. Accordingly, we have proposed here a tumor vascular microenvironment remodeling strategy based on NO-induced vessel normalization and extracellular matrix collagen degradation with multimodality imaging-guided nanoparticles against TNBC called DNMF/PLGA.ResultsNanoparticles were synthesized using a chemotherapeutic agent doxorubicin (DOX), a NO donor L-arginine (L-Arg), ultrasmall spinel ferrites (MnFe2O4), and a poly (lactic-co-glycolic acid) (PLGA) shell. Nanoparticle distribution in the tumor was accurately monitored in real-time through highly enhanced magnetic resonance imaging and photoacoustic imaging. Near-infrared irradiation of tumor cells revealed that MnFe2O4 catalyzes the production of a large amount of reactive oxygen species (ROS) from H2O2, resulting in a cascade catalysis of L-Arg to trigger NO production in the presence of ROS. In addition, DOX activates niacinamide adenine dinucleotide phosphate oxidase to generate and supply H2O2. The generated NO improves the vascular endothelial cell integrity and pericellular contractility to promote vessel normalization and induces the activation of endogenous matrix metalloproteinases (mainly MMP-1 and MMP-2) so as to promote extravascular collagen degradation, thereby providing an auxiliary mechanism for efficient nanoparticle delivery and DOX penetration. Moreover, the chemotherapeutic effect of DOX and the photothermal effect of MnFe2O4 served as a chemo-hyperthermia synergistic therapy against TNBC.ConclusionThe two therapeutic mechanisms, along with an auxiliary mechanism, were perfectly combined to enhance the therapeutic effects. Briefly, multimodality image-guided nanoparticles provide a reliable strategy for the potential application in the fight against TNBC.Graphical

The effect of sodium nitroprusside on the vegetative development of Aronia melanocarpa [Michx.] Elliot under in vitro conditions

Aronia is a berry fruit that has a significant amount of antioxidants. Both sexual and vegetative methods of propagation are available for aronia. Genetic diversity is present in the process of seed propagation. Therefore, clonal propagation techniques such as cuttings, basal shoots, and tissue culture are preferred. Plant tissue culture is a process that offers a high multiplication rate and the ability to produce clean plant material. This study aimed to stimulate the growth of plantlets by introducing several growth-promoting agents into the culture media. Specifically, the effects of a nitric oxide donor SNP (sodium nitroprusside) on the vegetative development of the plants were examined under in vitro conditions. Four distinct concentrations of SNP (0, 100, 200, and 300 µM) were administered to promote vegetative development. The survival rate (%), rooting rate (%), root number (per plantlet), root length (cm), leaf number (per plantlet), shoot length (cm), plant fresh weight (g), and plant dry weight (g) of the plantlets were estimated on the 60th day of growth in the nutrient medium under in vitro conditions. The survival rate was 100% for the applications of SNP at concentrations of 100 µM and 200 µM. The 0 µM treatment had the highest root number, the 100 µM treatment had the longest root, and the 200 µM treatment had the highest values for shoot length. The 0 µM treatment provided the highest values for plant fresh weight, while the 0 and 100 µM applications resulted in the highest plant dry weight values. The study suggested that an increased concentration of SNP causes a toxic effect.

Characterization of leucine aminopeptidase (LAP) activity in sweet pepper fruits during ripening and its inhibition by nitration and reducing events

Key messagePepper fruits contain two leucine aminopeptidase (LAP) genes which are differentially modulated during ripening and by nitric oxide. The LAP activity increases during ripening but is negatively modulated by nitration.Leucine aminopeptidase (LAP) is an essential metalloenzyme that cleaves N-terminal leucine residues from proteins but also metabolizes dipeptides and tripeptides. LAPs play a fundamental role in cell protein turnover and participate in physiological processes such as defense mechanisms against biotic and abiotic stresses, but little is known about their involvement in fruit physiology. This study aims to identify and characterize genes encoding LAP and evaluate their role during the ripening of pepper (Capsicum annuum L.) fruits and under a nitric oxide (NO)-enriched environment. Using a data-mining approach of the pepper plant genome and fruit transcriptome (RNA-seq), two LAP genes, designated CaLAP1 and CaLAP2, were identified. The time course expression analysis of these genes during different fruit ripening stages showed that whereas CaLAP1 decreased, CaLAP2 was upregulated. However, under an exogenous NO treatment of fruits, both genes were downregulated. On the contrary, it was shown that during fruit ripening LAP activity increased by 81%. An in vitro assay of the LAP activity in the presence of different modulating compounds including peroxynitrite (ONOO−), NO donors (S-nitrosoglutathione and nitrosocyteine), reducing agents such as reduced glutathione (GSH), l-cysteine (l-Cys), and cyanide triggered a differential response. Thus, peroxynitrite and reducing compounds provoked around 50% inhibition of the LAP activity in green immature fruits, whereas cyanide upregulated it 1.5 folds. To our knowledge, this is the first characterization of LAP in pepper fruits as well as of its regulation by diverse modulating compounds. Based on the capacity of LAP to metabolize dipeptides and tripeptides, it could be hypothesized that the LAP might be involved in the GSH recycling during the ripening process.

Hyperaemia during dynamic handgrip exercise is preserved in healthy young subjects after recovery from COVID-19.

We sought to investigate possible impaired hyperaemia during dynamic handgrip exercise (HGE) in young healthy individuals who had recovered from COVID-19. We tested the vascular function in individuals recovered from COVID-19 using a nitric oxide donor (i.e., sodium nitroprusside; SNP), which could revert a possible impaired endothelial function during HGE. Further, we tested whether individuals who recovered from COVID-19 would present exaggerated brachial vascular resistance under an adrenergic agonist (i.e., phenylephrine; PHE) stimuli during HGE. Participants were distributed into two groups: healthy controls (Control; men: n=6, 30±3years, 26±1kg/m2 ; and women: n=5, 25±1years, 25±1kg/m2 ) and subjects recovered from COVID-19 (post-COVID; men: n=6, 29±3years, 25±1kg/m2 ; and women: n=10, 32±4years, 22±1kg/m2 ). Participants in the post-COVID group tested positive (RT-PCR) 12-14weeks before the protocol. Heart rate (HR), brachial blood pressure (BP), brachial blood flow (BBF) and vascular conductance (BVC) at rest were not different between groups. The HGE increased HR (Control: Δ9±0.4bpm; and post-COVID: Δ11±0.4bpm) and BP (Control: Δ6±1mmHg; and post-COVID: Δ12±0.6mmHg) in both groups. Likewise, BBF (Control: Δ632±38ml/min; and post-COVID: Δ620±27ml/min) and BVC (Control: Δ6.6±0.4ml/min/mmHg; and post-COVID: Δ6.1±0.3ml/min/mmHg) increased during HGE. SNP did not change HGE-induced hyperaemia but did decrease BP, which induced a reflex-related increase in HR. PHE infusion also did not change the HGE-induced hyperaemia but raised BP and reduced HR. In conclusion, exercise-induced hyperaemia is preserved in healthy young subjects 12-14weeks after recovery from COVID-19 infection.