Reliable and minimally invasive biomarkers are needed for early detection, prognosis, and monitoring of colon cancer (CC). The aim of our study was to evaluate the role of systemic nitric oxide (NO) in inflammation and tumor progression and its diagnostic and prognostic value in CC. This prospective monocentric case-control study included 130 patients with non-metastatic CC and 100 healthy subjects. Clinical and pathological data were collected, and blood cell count-derived ratios were calculated. Systemic nitrite and cytokines levels were assessed using Griess method and ELISA respectively. Tumor-infiltrating immune cells were evaluated by immunohistochemistry in 44 patients. ROC curves, Kaplan-Meier, and log-rank tests were performed to highlight the diagnostic and prognostic value of NO production in patients followed for two years. Systemic plasma nitrite levels were significantly higher in patients than in controls (p < 0.0001), and correlated significantly and positively with most inflammatory and tumor markers and CD68+ cells and CD4+ T cells, but negatively with IL-6, albumin and CD8+ T cells. Interestingly, high nitrite levels were associated with tumor progression (cancer stage, tumor size, lymph node ratio). ROC analysis confirmed a high diagnostic performance (AUC = 0.88 for patients vs. controls; AUC = 0.71 for early vs. advanced stages). Prognostically, elevated nitrite levels predicted postoperative complications (AUC = 0.67; p log-rank<0.0001), reduced recurrence-free survival (AUC = 0.70; p log-rank = 0.03), and reduced overall survival (AUC = 0.75; p log-rank = 0.04). Our findings indicate that systemic nitrite levels are closely linked to inflammation and tumor progression in CC and demonstrate strong predictive accuracy, emerging as a promising biomarker for patient management.
Nitric oxide (NO) produced by endothelial cells plays a central role in regulating vascular tone, blood flow, and inflammatory responses. Although NO freely diffuses across cell membranes, intracellular and extracellular NO-related signals are often measured interchangeably, complicating interpretation of NO production, signaling, and bioavailability. Moreover, how cryopreservation and experimental context influence these two measurement compartments remains poorly defined. Here, we systematically compared intracellular and extracellular NO-related fluorescence in mouse cardiac endothelial cells (MCECs) under defined stimulatory, inhibitory, and culture conditions. Using DAF-FM DA (4-amino-5-methylamino-2',7'-difluorofluorescein diacetate) and DAF-FM-based assays, we examined (i) the impact of cryopreservation on intra- and extracellular NO-related signals following calcium ionophore A23187 stimulation, and (ii) the effects of physiological stimulation (bradykinin), enzymatic inhibition (Nᴳ-Nitro-l-arginine methyl ester (l-NAME)), and NO scavenging (carboxy-PTIO potassium salt (cPTIO)) in non-cryopreserved cells. Calcium ionophore A23187 increased intracellular NO-related fluorescence across non-cryopreserved and post-thaw groups, whereas extracellular responses were smaller and more variable, with increases observed primarily in glycerol-cryopreserved cells. The removal of phenol red from the medium enhanced extracellular NO-related fluorescence (reflecting improved detection sensitivity) but reduced intracellular signals, indicating a strong influence of medium composition on NO-related measurements. Bradykinin produced dose-dependent increases in extracellular signals accompanied by reductions in intracellular signals, consistent with rapid diffusion and context-dependent intracellular detection. l-NAME reduced intracellular fluorescence and suppressed extracellular signals only under simplified buffer conditions, while cPTIO produced modest reductions in extracellular fluorescence with substantial variability. Together, these findings indicate that intracellular and extracellular NO-related fluorescence are differentially regulated by stimulation, membrane properties, oxidative environment, and assay conditions. The results underscore the importance of compartment-specific, method-aware interpretation when using fluorescence-based approaches to assess NO signaling in endothelial cell models, particularly in the context of cryopreservation and experimental reproducibility.
Glioblastoma is the most common primary malignant brain tumor with poor prognosis. The immunosuppressive microenvironment and cancer stem cells (CSCs) drive therapeutic resistance. The role of nitric oxide (NO) metabolism in coordinating glioma stemness and immune evasion remains unclear. We performed multi-omics analysis using CGGA, TCGA, and Rembrandt datasets (n = 1500) and single-cell RNA sequencing (n = 65,655 cells). PRMT1 was identified as a key NO metabolism-associated prognostic gene through Cox regression and LASSO modeling. Validation used glioma cell lines, patient-derived GSCs, and orthotopic mouse models. NO metabolism activity increased with glioma grade and correlated with poor survival (p < 0.001). Single-cell analysis showed positive correlation between NO metabolism and stemness (R = 0.35, p < 0.001). High-NO metabolism tumors showed M0 macrophage enrichment (p < 0.001) and M1 depletion (p < 0.05). PRMT1 expression was elevated in high-grade gliomas and correlated with NOS2 (R = 0.26-0.46, p < 0.001). PRMT1 knockdown reduced proliferation (76%), colony formation (75%), and CD133+ cells (11.74% to 3.11%). NO donor treatment rescued knockdown effects. In vivo PRMT1 silencing reduced tumor growth to 35% of controls (p < 0.001) and decreased SOX2 and PD-L1 expression. PRMT1 links NO metabolism to glioma stemness and immunosuppression by regulating stemness factors (OCT4, SOX2) and immune checkpoints (PD-L1) through NO-dependent mechanisms. PRMT1 represents a therapeutic target that could disrupt stem cell populations and remodel the immunosuppressive microenvironment.
Nitric oxide (NO) is a widespread signaling molecule which has far-reaching effects in cellular physiology and pathophysiology, especially in cancer biology. Its actions are concentration-dependent where low concentrations facilitate tumor development and high concentrations cause cytotoxicity. NO alters several cancer hallmarks, affecting the initiation, progression, immune evasion, and therapeutic responses of tumors via cGMP-dependent and -independent pathways. Various cell types in the tumor microenvironment (TME) produce NO in a concentration gradient creating a strong concentration gradient that forms the immune landscape. NO mediates immunosuppression through the regulation of tumor-associated macrophage, myeloid-derived suppressor cell, T cells, and natural killer cells. It also controls angiogenesis and normalization of the vasculature via the VEGF-NO axis. Moreover, NO effects epithelial-mesenchymal transition and metastasis concentration-dependently. Notably, NO exists in a complex interaction with gasotransmitters, and it interacts with hydrogen sulfide and carbon monoxide in crosstalk to control cancer biology. Therapeutic interventions that focus on NO e.g., NO donors, iNOS-inhibitors and nanodelivery systems have been promising in preclinical practice. Nevertheless, clinical translation is complicated by the fact that the concentrations of intratumoral NO have to be tightly controlled, safety issues exist, and there are not many biomarkers of patient stratification. Integration of NO-based therapies with immunotherapy and precision medicine approaches holds promise for enhancing treatment outcomes. Continued research spanning chemical, biological, and clinical domains is crucial for unlocking the full therapeutic potential of NO in cancer.
Nitric oxide (NO) is involved in the regulation of vascular, immune and metabolic functions. Physiological modelling of stable isotope tracers provides an accurate method to measure whole-body NO production in humans. A systematic review and meta-analysis of studies using stable isotope methods was conducted to measure in vivo NO production in healthy individuals and patients with various disease conditions, characterise production rates across different populations and assess methodological factors contributing to measurement variability. PubMed/MEDLINE, Embase, Scopus and Web of Science databases were searched from inception to April 2025. Random-effect models were used to estimate of NO production. Risk of bias was assessed using the BIOCROSS scale for biomarker studies. Publication bias was evaluated by Funnel Plots and Egger's regression test. 58 studies were included in the systematic review, and 42 had valid data to be included in the meta-analysis. Mean NO production in healthy adults was 0.74 (95 %CI 0.47, 1.00) μmol·kg-1·hour-1 and ranged from 0.73 to 4.89 μmol kg-1·hour-1 depending on methodology and population characteristics. NO production in cardiovascular diseases [0.19 (95 %CI 0.11, 0.28) μmol·kg-1·hour-1] and metabolic diseases [0.43 (95 %CI 0.21, 0.64) μmol·kg-1·hour-1] was associated with lower physiological NO production. Conversely, chronic kidney disease [5.42 (95 %CI 2.04, 8.81) μmol·kg-1·hour-1] and inflammatory conditions [1.35 (95 %CI 0.78, 1.92) μmol·kg-1·hour-1] were associated with increased NO production. Chronic metabolic and cardiovascular diseases were overall characterised by a lower NO production. Standardisation of stable isotope protocols and reference ranges are needed to improve clinical utility for monitoring and therapy.
Coccidiosis, a parasitic disease in animals, is often treated with coccidiostats, but their excessive use has led to drug resistance, reducing treatment efficacy. This study sought to investigate the in vitro and in vivo anticoccidial capacity of zinc oxide nanoparticles using Coriandrum sativum extract (CSE-ZnONPs) against Eimeria papillata. CSE-ZnONPs were synthesized and characterized via transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). E. papillata oocysts were treated in vitro with decreasing selected concentrations from CSE-ZnONPs (100 - 0.5 mg/ml K2Cr2O7) of CSE-ZnONPs for 96 h as part of a sporulation inhibition assay. For In vivo, five groups (G) of mice were utilized: G1: control group (Non-Infected), G2: received CSE-ZnONPs, G3: infection group with 10³ sporulated oocysts (Infected). G4: infected and treated with CSE-ZnONPs at a dosage of 50 mg/kg b.w. (Infected + CSE-ZnONPs). G5: infected and treated with amprolium at a dosage of 120 mg/kg b.w. (Infected + Amp). The treatments were persisted for five days. In vitro results indicated that CSE-ZnONPs markedly decreased sporulation rates and caused morphological damage in E. papillata oocysts. The in vivo oral administration of CSE-ZnONPs to infected mice considerably reduced the numbers of jejunal endogenous stages and notably decreased their morphometric dimensions. Immunohistochemistry demonstrated a downregulation of Cluster of Differentiation 4 (CD4) and Inducible Nitric Oxide Synthase (iNOS) expression, whereas biochemical antioxidant studies indicated reduced nitric oxide and malondialdehyde levels, alongside elevated superoxide dismutase and catalase activity. ELISA verified reduced serum concentrations of interferon-γ, tumor necrosis factor-α, interleukin-10, and iNOS in the treated mice. CSE-ZnONPs possess a promising potent in vitro sporulation inhibition and in vivo anticoccidial, antioxidant, anti-inflammatory and immuno-therapeutic properties against E. papillata.
Chronic inflammation accompanied by oxidative imbalance plays an essential role in the pathogenesis of ulcerative colitis (UC). Suaeda fruticosa has well-established antioxidant, cytoprotective and anti-inflammatory properties. This study evaluated the efficacy of the 80% ethanolic extract of S. fruticosa and its primary phytoconstituents in experimental models of UC. Ethanolic extract of Suaeda fruticosa (SF-Et) prepared by maceration was characterised by quantitative (TPC, TFC, TTC, and TSC) and GC-MS techniques. The nitrite scavenging assay was performed to determine the reactive nitrogen species (RNS) scavenging property. 5% dextran sulfate sodium (DSS, 40KDa Mw) and 3% acetic acid (2 mL) solutions were used to induce UC in rats. Animals were treated with 125, 250, and 500 mg/kg of SF-Et, 500 mg/kg of sulfasalazine, and 10 mg/kg of the compound combination (CC). Physical parameters, such as body weight, stool consistency, and rectal bleeding were examined to determine the severity of UC. Histopathological observations of colon tissues, haematological testing, and qPCR analysis of inflammatory genes were performed to establish the in vivo efficacy of SF-Et. Additionally, the MTT assay was used to evaluate the cytotoxicity of SF-Et and its components against HCT 116 colorectal cancer cells. ADMET predictions for selected compounds were performed using online tools. Quantitative phytochemical screening confirmed the presence of 69.49 ± 6.27 mg GAE/g of TPC, 353.01 ± 8.05 mg QE/g of TFC, 21.7% of TSC, and 34.26 ± 2.02 mg TAE/gram of TTC in SF-Et. GC-MS analysis confirmed the presence of farnesol, n-hexadecanoic acid, and thymol  (previous data). Nitrite scavenging activity confirmed the moderate RNS scavenging potential of SF-Et. In DSS and acetic acid-induced colitis models, oral administration of 500 mg/kg of SF-Et and 10 mg/kg of the compound combination significantly mitigated colitis signs, restored haematological parameters, and protected the architecture of colon tissues. qPCR analysis revealed significant (p < 0.05) down-regulation in mRNA expression of inflammatory markers (TNF-α, IL-1β, IL-6, iNOS, COX-2, NF-κB, and PGE2) and up-regulation of the anti-inflammatory cytokine, IL-10, in the SF-Et, CC and SSZ administered groups. Treatment with SF-Et and SSZ produced significant (p < 0.05) elevation in serum GSH and reduction in nitric oxide levels than diseased control group. Moreover, SF-Et and the CC treatment showed dose-dependent cytotoxicity against HCT 116 cells. ADMET prediction showed good intestinal absorption (> 90%) and a relatively low toxicity profile of studied compounds. These findings confirm that S. fruticosa and its major compounds can mitigate UC development by modulating inflammatory and oxidative stress biomarkers.
S-Nitrosoglutathione (GSNO) is an endogenous nitric oxide (NO) donor molecule. Photolysis of solid GSNO may be utilized effectively as an NO source for inhaled nitric oxide (iNO) therapy. In this work, solid GSNO was photolyzed using narrow-band LED lights as a function of wavelength and intensity of incident light. The photolytic NO release efficiency, the presence of any decomposition products, as well as the morphology and the photolytic pathways for GSNO photo-decomposition were examined using NMR, UV, FTIR, ESR, TGA, DSC, SEM and UPLC-MS. The initial photochemical yield for NO release was 0.37±0.03%, 0.10±0.01%, and 0.02±0.01% (n = 3 independent experiments) respectively using 340 nm, 385 nm, and 470 nm of LED light sources. The photolyzed solid GSNO reacted with oxygen in ambient air and immediately produced an oxygenated glutathione-derived species with m/z ratio (∼354) suggesting the possible formation of sulfonyl peroxyl radical GS(O)2O• without a measurable stable thiyl radical formation. However, the photolyzed product did not recombine with NO to reform the GSNO, strongly suggesting that the photolysis of GSNO is irreversible under our conditions. Based on PXRD and SEM analysis, after photolysis and NO generation the GNSO lost its crystallinity. Hence, these data may prove useful for development of GSNO as a solid phase NO source for iNO therapy.
Indigofera truxillensis Kunth is traditionally used in Brazilian folk medicine as an oral infusion of the aerial parts, taken as one cup several times daily for at least one week, to relieve inflammatory pain and gastrointestinal complaints. To chemically characterize and evaluate the anti-arthritic and analgesic properties of the methanolic extract (MEIT) and indigo obtained from the aerial parts of I. truxillensis. The chemical analysis of MEIT and the identification of indigo were performed by electrospray ionization tandem mass spectrometry and nuclear magnetic resonance. Anti-inflammatory and anti-hyperalgesic activities were assessed in mice using carrageenan-induced pleurisy and paw inflammation, complete Freund's adjuvant (CFA), and zymosan-induced articular inflammation models. Cytotoxicity and phagocytic activity were evaluated in vitro using leukocyte viability (MTT) and neutrophil phagocytosis assays. MEIT and indigo significantly inhibited leukocyte recruitment in carrageenan-induced pleurisy. In the carrageenan paw model, both reduced mechanical hyperalgesia, cold sensitivity, and edema. In CFA-induced inflammation, MEIT and indigo decreased mechanical hyperalgesia, cold response, myeloperoxidase activity, and protein exudation. In the zymosan-induced arthritis model, both treatments reduced knee edema, mechanical hyperalgesia, leukocyte migration, protein extravasation, and nitric oxide levels in synovial fluid. MEIT and indigo did not exhibit cytotoxicity in vitro; MEIT reduced neutrophil phagocytosis at specific concentrations, whereas indigo did not alter phagocytic activity. MEIT and indigo exhibit significant anti-inflammatory, anti-hyperalgesic, and anti-arthritic activities, supporting the traditional use of I. truxillensis for painful and inflammatory conditions and identifying indigo as a key bioactive constituent.
Zinc (Zn) deficiency significantly impacts plant growth and productivity in agriculture. Seed priming is a promising strategy to enhance plant tolerance to nutrient deficiencies. This study examines the effects of priming barley (Hordeum vulgare L.) seeds with silicon nanoparticles (SiNPs), nitric oxide (NO), and their combination on germination and growth under Zn-deficient conditions. Primed seedlings showed superior growth, and improved photosynthetic efficiency, antioxidant enzyme activities, the ascorbate-glutathione cycle function, nutrient-related gene expression, and sucrose metabolism compared to the un-primed seedlings. Among the priming methods, the combination of SiNPs and NO had the most significant positive effect on barley growth under Zn deficiency. Priming of seeds with SiNPs was more effective against Zn deficiency than external SiNPs application at the seedling stage. Exogenous SiNPs added to already SiNPs-primed seedlings further improved growth under Zn deficiency. Contrary to this, NO addition to NO-primed seedlings inhibited growth due to excessive endogenous NO accumulation. Co-application of SiNPs and NO to SiNPs+NO- primed seedlings led to severe growth retardation due to build-up of endogenous NO production. These findings highlight seed priming's potential, especially with SiNPs, to address nutrient deficiencies in agriculture and the complex interactions of endogenous NO in priming-mediated regulation of Zn deficiency in barley.
This study evaluated free astaxanthin (ASX) and astaxanthin-loaded chitosan nanoparticles (ASX-CNPs) as additives to semen freezing extenders for Egyptian buffalo bulls. Five healthy and fertile buffalo bulls were used, and forty ejaculates were collected over eight consecutive weeks. Ejaculates that met standard quality criteria were pooled to eliminate individual bull variation, diluted with a Tris-egg yolk extender, and allocated into three experimental groups: a control group without supplementation, a group supplemented with 127 μM free ASX, and a group supplemented with 127 μM ASX-CNPs. Semen samples were cryopreserved in liquid nitrogen for one month and subsequently evaluated after thawing. The results showed that supplementation with ASX-CNPs significantly improved post-thaw progressive motility, sperm viability, plasma membrane integrity, and acrosomal integrity compared with both the control and free ASX groups (p < 0.05), while sperm abnormalities were significantly reduced. Moreover, ASX-CNPs significantly improved sperm kinematic parameters. Antioxidant analysis revealed significant increases in total antioxidant capacity and the activities of catalase and glutathione peroxidase, accompanied by significant reductions in nitric oxide, malondialdehyde, and hydrogen peroxide levels. In addition, ASX-CNPs significantly decreased apoptotic and necrotic spermatozoa, downregulated the pro-apoptotic genes Bax and Caspase-3, and upregulated the anti-apoptotic gene BCL2. Ultrastructural observations confirmed preservation of sperm membrane, acrosomal, and mitochondrial integrity. Furthermore, ASX-CNPs reduced semen microbial load and improved fertility, increasing pregnancy rates by 24.28% compared with the control. In conclusion, ASX-CNPs represent a promising nano-antioxidant additive for buffalo semen cryopreservation, offering superior protection and enhanced fertility outcomes compared with free ASX.
Neuronal nitric oxide synthase (nNOS) is a therapeutic target for the treatment of various neurological disorders and for melanoma. As part of our ongoing efforts to develop potent and selective nNOS inhibitors, we modified our previously reported compound 3 to 4 by introducing an ether linker, leading to a new series of ether-linked 2-aminopyridine-based compounds that exhibit high potency, isoform selectivity, and membrane permeability. Among them, lead compound 4 inhibits human nNOS with a Ki of 25 nM and exhibits 2300-fold selectivity over human endothelial NOS (eNOS) while also displaying high effective permeability in the parallel artificial membrane permeability assay for the blood-brain barrier (PAMPA-BBB) assay (Pe = 16.67 × 10-6 cm/s), indicating favorable blood-brain barrier penetration. Pharmacokinetic evaluation confirmed the brain penetrance of 4 and demonstrated a high oral bioavailability (77%). Moreover, the X-ray crystal structures of representative compounds bound to three NOS isoforms (hnNOS, rnNOS, and heNOS) revealed key binding interactions that contribute to both potency and selectivity.
Neuronal nitric oxide synthase (nNOS) is a key enzyme in neurodegenerative diseases and melanoma, making it an important therapeutic target. We previously reported 2-aminoquinoline-based nNOS inhibitors with promising activity but limited by suboptimal potency, isoform selectivity, and off-target effects. To address these issues, we designed and synthesized a new series of 7-aryl-6-fluoro-4-methyl-2-aminoquinoline derivatives. Compound 16 showed excellent potency against human nNOS (Ki 16 nM), with ∼1800-fold selectivity over human endothelial NOS (eNOS) and ∼2900-fold over human inducible NOS (iNOS). PAMPA-BBB experiments indicated high effective permeability (Pe = 13.04 × 10-6 cm/s), suggesting strong CNS drug potential. In vivo pharmacokinetic studies in mice further demonstrated sustained systemic exposure, low clearance, and robust brain penetration. In contrast, compound 24, the N-Me analogue of 16, was inactive. Molecular dynamics simulations indicated that N-methylation disrupted the favorable solvation of the tail amino group, likely contributing to its loss of activity and nNOS affinity.
Methotrexate (MTX) is a widely used chemotherapeutic and immunosuppressive agent, but its clinical utility is limited by oxidative stress-mediated renal toxicity. This study evaluated the nephroprotective potential of the dietary polyphenolic bioactive molecule piceatannol (PIC) in its crude and liposomal nanoparticle (PIC-LNP) forms against MTX-induced kidney injury in rats. Sixty rats were allocated into six groups and received vehicle, PIC, PIC-LNPs, MTX, or combinations of MTX with PIC or PIC-LNPs. MTX administration induced marked renal dysfunction and oxidative/nitrosative stress, reflected by elevated serum urea, creatinine, and uric acid, together with increased renal ROS, MDA, protein carbonyls, 8-OHdG, and nitric oxide, in parallel with suppression of the Nrf2/HO-1 antioxidant pathway. These disturbances were accompanied by activation of TLR4/NF-κB and MAPK signaling, upregulation of pro-inflammatory cytokines, and a shift toward apoptosis, as evidenced by increased Bax and caspase-3 and reduced Bcl-2 expression. Histological and ultrastructural analyses confirmed extensive glomerular and tubular damage with mitochondrial disruption and cytoplasmic vacuolations. PIC treatment attenuated these MTX-induced alterations, whereas the liposomal formulation conferred superior protection. PIC-LNPs restored Nrf2/HO-1 signaling, enhanced endogenous antioxidant defenses, reduced oxidative/nitrosative and inflammatory responses, and normalized apoptotic markers, accompanied by substantial preservation of renal architecture and cellular integrity. Immunohistochemistry demonstrated strong Nrf2 expression with minimal NF-κB activation in the PIC-LNP group. Collectively, these findings highlight liposomal piceatannol as a promising bioactive-molecule-based strategy for controlling oxidative stress and mitigating chemotherapy-associated oxidative-stress-related renal injury.
This study aimed to evaluate the effects of ginger essential oil nanoemulsion (GEONE) supplementation on growth performance, feed efficiency, and overall health status in heat-stressed growing rabbits. A total of 96 healthy 5-week-old APRI male rabbits were randomly assigned to four homogeneous groups (24 rabbits per group) and fed diets supplemented with 0, 100, 200, or 400 mg of GEONE per kilogram of feed. Dietary supplementation with 200 mg GEONE/kg diet significantly improved growth performance, as evidenced by increased average daily weight gain by 8.14% and dressing percentage by 7.77%, alongside significant reductions in feed conversion ratio by 8.65%, rectal temperature by 1.63% and respiration rate by 9.06%. Liver enzyme activities declined in a dose-dependent manner, while total blood proteins, their fractions, and thyroid hormone concentrations were significantly elevated. Concurrently, levels of total cholesterol, triglycerides, urea, creatinine, and cortisol were significantly reduced. Antioxidant capacity was enhanced, reflected by higher total antioxidant activity and increased activities of catalase, glutathione peroxidase, and superoxide dismutase. Immune function was also strengthened, with notable elevations in immunoglobulins M and G by 16.95% and 38.29%, respectively. Indicators of oxidative stress, including malondialdehyde, protein carbonyls, and 8-hydroxy-2'-deoxyguanosine, were markedly reduced, while concentrations of pro-inflammatory cytokines were significantly lowered, and nitric oxide levels were significantly increased. Histological evaluations further corroborated these findings, demonstrating protection against heat stress through preservation of normal liver and kidney architecture. In conclusion, supplementation with 200 mg of GEONE/kg of diet effectively improved growth performance, feed utilization, liver and kidney function, antioxidant defense, immune response, and inflammatory regulation in fattening rabbits exposed to summer heat stress.
Nitric oxide (NO) has a wide range of effects in both animals and plants. It accumulates in cells, especially during stress responses, leading to signalling events. Many of these downstream signals rely on S-nitrosation, or nitration of proteins, but NO also interacts with a range of other cellular components, including lipids, but also other small reactive compounds. A well-known example of such a NO reaction is with the reactive oxygen species (ROS) superoxide, producing peroxynitrite (ONOO-). One characteristic of cells which is crucial to the control of cellular activity is the intracellular redox state, and this is maintained by compounds such as glutathione (GSH), but also impinged upon by ROS, reactive sulfur compounds such as hydrogen sulfide (H2S), and potentially by hydrogen gas (H2). Into this mix is NO, and here the potential influence of NO on cellular redox is discussed.
Apolipoprotein M (ApoM) is a lipocalin predominantly associated with high-density lipoprotein (HDL) that transports sphingosine-1-phosphate (S1P) in circulation. Through its stable binding and selective delivery of S1P to the endothelial S1P receptors (S1PRs), ApoM orchestrates a spectrum of vasoprotective effects. This review summarizes the structural characteristics of ApoM and its unique function as a sphingolipid chaperone, focusing on its role in vascular biology, specifically endothelial barrier integrity, vascular tone, and inflammation. We examine the biased signaling of ApoM-HDL-S1P through S1PR1 and its implications in modulating nitric oxide production and endothelial adherens junction assembly. In addition, circulating ApoM+-HDL appears to be important in transendothelial HDL transport and cholesterol efflux. Clinical and preclinical studies have linked reduced ApoM expression with cardiometabolic diseases, such as obesity, insulin resistance, type 2 diabetes, and chronic kidney disease, while emerging evidence also implicates ApoM in neurovascular, inflammatory, and retinal disorders. ApoM expression and plasma levels are regulated by hepatocyte nuclear factors, Forkhead box O nuclear transcription factors and inflammatory cytokines but also pharmacologically by statins and SGLT2 inhibitors. Recent development of engineered ApoM-based biologics, such as ApoM-Fc and ApoA1-ApoM fusion proteins, shows promise in preclinical models of vascular disease, demonstrating improvements in endothelial function, inflammation, and pathological neovascularization without inducing immunosuppression or bradycardia. Collectively, these insights position ApoM as both a critical biomarker and a therapeutic target for vascular health. Advancing ApoM-based therapies may offer a novel precision medicine strategy to treat cardiovascular and metabolic diseases through endothelial-targeted modulation of S1P signaling.
Tecoma stans (T. stans) is traditionally employed in folk medicine for the management of inflammatory conditions; however, its pharmacological properties and underlying mechanisms of action remain insufficiently characterized. This study aimed to evaluate the anti-inflammatory, antioxidant, and cytoprotective effects of the methanolic flower extract of T. stans using both in vitro and in vivo models, with particular emphasis on cytokines, modulation, oxidative stress markers, and lipid-derived inflammatory mediators. Cytotoxicity and hemotoxicity were assessed using MTT reduction and hemolysis assays, respectively. Anti-inflammatory activity was evaluated employing carrageenan-induced paw oedema and xylene-induced ear oedema models. Modulation of cytokine (TNF-α, IL-1β, IL-6, IL-10) was determined in both in vivo and in vitro models. Additionally, the effects of the extract on nitric oxide (NO), hydrogen peroxide (H2O2), leukotriene B4 (LTB4), and prostaglandin E2 (PGE2) production were analyzed. T. stans extract exhibited no cytotoxic or hemolytic effects, maintaining cell viability above 90%. It significantly attenuated inflammatory responses in edema models, reduced pro-inflammatory cytokines and mediator levels, and increased IL-10 production. Furthermore, the extract markedly decreased NO and H2O2 generation, indicating a reduction in oxidative stress. These findings support the anti-inflammatory and antioxidant potential of T. stans, mediated through cytokine modulation, attenuation of oxidative stress, and partial inhibition of COX/LOX pathways. Collectively, its pharmacological profile highlights its potential as a natural therapeutic agent for the management of inflammatory disorders.
Chronic diabetic wounds remain a major clinical challenge due to impaired healing processes driven by oxidative stress. This study evaluates the effects of Capparis spinosa and glutamine, administered individually or in combination, on diabetic wound healing with a focus on the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. Forty-two adult male Wistar albino rats with streptozotocin (STZ)-induced diabetes and excisional wounds were allocated into seven groups: control, untreated, glutamine-treated, C. spinosa (topical and oral), and combined C. spinosa + glutamine (topical and oral). On day 7, wound tissues were analyzed for Nrf2, HO-1, matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and collagen levels using ELISA. Oxidative stress markers, including malondialdehyde (MDA), nitric oxide (NOx), protein carbonyl (PC), glutathione (GSH), and ascorbic acid (AA), were measured spectrophotometrically, alongside morphological and histopathological evaluations. Combined treatment significantly decreased MDA, NOx, PC, MMP-2, and MMP-9 levels, while increasing GSH, AA, and collagen levels. These changes were associated with enhanced wound closure, reduced inflammation, and improved tissue remodeling. Both individual and combined treatments promoted Nrf2 activation and normalized HO-1 expression. Overall, C. spinosa and glutamine enhance diabetic wound repair by restoring redox balance and strengthening endogenous antioxidant defense mechanisms.
In this work, Eucalyptus salubris seeds extract (ESS) was characterized using liquid chromatography (LC) coupled to mass spectrometry (MS), and its in vitro and in vivo anti-inflammatory properties were evaluated. Through LC-MS and MS2 analysis, flavanonols and monounsaturated fatty acids were found to be the most abundant components, while unreported galloylated flavanonols were profiled. ESS attenuated the denaturation of Bovine Serum Albumin (BSA), significantly stabilized rats Red Blood Cells (RBC) membranes, and inhibited both Cyclooxygenase-1 (COX-1) and Cyclooxygenase-2 (COX-2) enzymes, indicating its ability to reduce inflammation. The in vivo study showed that ESS significantly reduced the carrageenan-induced paw edema in rats and normalized the inflammatory cytokines Tumor Necrosis Factor-alpha (TNF-α) and Interleukin-6 (IL-6) levels. In addition, ESS alleviated formaldehyde-induced arthritis symptoms through a remarkable reduction in oxidative stress biomarkers (evidenced by decreased Malondialdehyde (MDA), Glutathione (GSH), and Nitric Oxide (NO) levels, along with increased Superoxide Dismutase (SOD) and Catalase (CAT) activities), as well as the restoration of the hematological profile (reduction in white blood cell (WBC) count and erythrocyte sedimentation rate (ESR), accompanied by an increase in red blood cell (RBC) count and hemoglobin (Hb) levels). These effects are largely attributable to the richness of ESS in phenolic compounds, flavonoids, and other bioactive secondary metabolites. Collectively, these findings supported the therapeutic potential of E. salubris extract as a natural source of anti-inflammatory and antioxidant agents, warranting further investigation for potential pharmaceutical or nutraceutical applications.