Nitric Oxide Synthase Activity Research Articles

Exposure of Zebrafish Embryos to Urea Affects NOS1 Gene Expression in Neuronal Cells

Nitrogen-based fertilizers represent the most common fertilization tools, particularly used in crop food agriculture, despite the low cost-efficiency and the high negative environmental impact. At present, there is still inadequate information available about the effects of urea on human health; nevertheless, previous studies in animals observed that high urea concentration exposure can damage different tissues, including the brain. In several vertebrates, a crucial factor involved in neuronal cell formation is represented by the gas molecule, nitric oxide (NO), derived from the conversion of arginine to citrulline through the enzymatic activity of nitric oxide synthases (NOS). In zebrafish, three different isoforms of the NOS gene are known: nos1, nos2a, and nos2b. In the present study we show that nos1 represents the unique isoform with a stable high expression in the brain and spinal cord during all the embryonic stages of zebrafish development. Then, by using a specific transgenic zebrafish line, Tg(HuC:GFP), to mark neuronal cells, we observed nos1 to be specifically expressed in neurons. Interestingly, we observed that urea exposure at sub-lethal doses affected cell proliferation and the number of nos1-expressing cells, inducing apoptosis. Consistently, brain NO levels were observed to be reduced in urea-treated animals compared to untreated ones. This finding represents the first evidence that urea exposure affects the expression of a key gene involved in neuronal cell formation during embryonic development.

Parameters of oxidative, nitrasive and anti-oxidative status in men with erectile dys-function due to combat trauma

The development of oxidative and nitrative stress and the processes of free radical oxidation are associated with many pathological processes. Damage of any origin leads to the activation of free radical processes not only in the place of damage, but also in the whole organism. The aim of the study is to assess the state of lipid peroxidation, content of GSH and GSSG and the activity of NO-synthase and arginase in lymphocytes and peripheral blood serum in men with erectile dysfunction due to combat trauma. The research was conducted on peripheral blood lymphocytes of men injured as a result of combat operations (shrapnel and bullet wounds) in the Russian-Ukrainian war, and who were treated at the Military Medical Clinical Center of the Western Region (Lviv, Ukraine). The research group of men with combat injuries was divided into two age groups: men aged 20–39 years and men aged 40–53 years. The MDA content in the blood serum of patients of both age groups was 1.35 times higher than in the control group. In peripheral blood lymphocytes, the MDA content in patients of the young age group was 1.27, and in patients of the middle age group in 1.39 times higher than in the control group. Simultaneously, no significant changes in the concentration of oxidized glutathione in blood serum and blood lymphocytes were found between men with erectile dysfunction due to combat trauma and healthy men. GSH content in blood serum in patients of both age groups was significantly lower than in the control group. The arginase/NOS ratio in blood serum was 9.75 times lower in the young age group and in 20.45 times lower in the middle age group compared to healthy men. It was established that in the blood serum and blood lymphocytes of men with erectile dysfunction due to combat trauma, processes of lipid peroxidation were intensified and the GSH level was reduced. The GSH/GSSG ratio was reduced only in blood serum. It was found that the oxidative stress is associated with development of nitrative stress. The arginase/NOS ratio was shifted towards increased NOS activity. Activation of iNOS was accompanied by significant inhibition of cNOS. Further study of biochemical mechanisms is important to understand the triggers of erectile dysfunction due to combat trauma.

Bisphenols and brominated bisphenols induced endothelial dysfunction via its disruption of endothelial nitric oxide synthase

Emerging literatures have concentrated on the association between cardiovascular diseases risk of typical endocrine disruptor bisphenols, which also put forward the further studies need respect to the potential mechanism. Herein, we investigated the endothelial dysfunction effects of bisphenols and brominated bisphenols involved in aortic pathological structure, endothelial nitric oxide synthase (eNOS) protein phosphorylation, synthase activity and nitric oxide (NO) production in human umbilical vein endothelial cells (HUVECs) and C57BL/6 mice. Bisphenol A (BPA) and bisphenol S (BPS) increased NO production by 85.7% and 68.8% at 10−6 M level in vitro and 74.3%, 41.5% in vivo, respectively, while tetrabromobisphenol S (TBBPS) significantly inhibited NO by 55.7% at 10−6 M in vitro and 28.9% in vivo at dose of 20 mg/kg BW/d. Aortic transcriptome profiling revealed that the process of ‘regulation of NO mediated signal transduction’ was commonly induced. The mRNA and protein expression of phosphorylated eNOS at Ser1177 were promoted by BPA and BPS but decreased by TBBPA and TBBPS in HUVECs. Phosphorylation and enzymatic activity of eNOS were significantly increased by 43.4% and 13.8% with the treatment of BPA and BPS at 10−7 M, but decreased by 16.9% after exposure to TBBPS at 10−6 M in vitro. Moreover, only TBBPS was observed to increase aorta thickness significantly in mice and induce endothelial dysfunction. Our work suggests that bisphenols and brominated bisphenols may exert adverse outcome on vascular health differently in vitro and in vivo, and emphasizes areas of public health concern similar endocrine disruptors vulnerable on the vascular endothelial function.

Potent Efficacy of 3-Amino-4-hydroxy Benzoic Acid, a Small Molecule Having Anti-fibrotic Activity, in a Mouse Model of Non-alcoholic Steatohepatitis.

Non-alcoholic steatohepatitis (NASH), which is on the rise due to the increasing obese population and changing lifestyles, causes fibrosis over time and carries the risk of progression to cirrhosis and hepatocellular carcinoma. However, there are no approved effective treatments for NASH. Recent studies suggest that increased lipid metabolism and reduced nitric oxide content are responsible for NASH; 3-amino-4-hydroxy benzoic acid (AHBA) was identified as an inhibitor for the phosphatase activity of soluble epoxy hydrolase, which in turn inhibits lipid metabolism and endothelial nitric oxide synthase activity. The aim of this study was to assess the efficacy of AHBA in a mouse model of NASH. NASH was induced in mice by streptozotocin administration and a high-fat diet loading. The efficacy of AHBA was determined by measuring liver function using serum and liver samples and conducting a morphological assessment. AHBA considerably attenuated the increase in the liver weight and alkaline phosphatase content, which occurred due to the progression of NASH. Hepatocellular steatosis, inflammatory cell infiltration, and hepatocellular ballooning of hepatocytes remained unaltered. In contrast, AHBA treatment significantly ameliorated the fibrotic alterations within liver tissue that were induced by the onset of NASH. These results demonstrate the potential of AHBA as a therapeutic pharmaceutical compound that can treat NASH.

Identify novel gene signatures in atrial fibrillation by comprehensive bioinformatics analysis

Background: Atrial fibrillation (AF), one of the most prevalent heart rhythm disorders, may lead to thromboembolism, heart failure, and sudden death. However, the mechanism of AF has not yet been fully explained. Objective: This study aims to identify novel gene signatures and to investigate the potential therapeutic targets of AF with an integrated bioinformatic approach. Methods: The gene expression and methylation datasets of AF were obtained through the Gene Expression Omnibus (GEO) database. Subsequently, a set of differentially expressed genes and differential methylation sites were identified. Gene functional annotation analysis was conducted to explore the potential function of differentially-methylated/expressed genes. Then, we constructed a PPI network and TF–miRNA–mRNA network. Finally, weighted gene co-expression network analysis (WGCNA) was presented to study critical modules of AF. Results: Seven hypomethylated-high expression genes and nine hypermethylated-low expression genes were acquired from AF patients. Functional enrichment results indicated that the differentially-methylated/expressed genes were mainly concentrated in decidualization, maternal placenta development, regulation of nitric-oxide synthase activity, and osteoclast differentiation. Based on the results of the PPI, we defined 4 key genes namely FHL2, STC2, ALPK3, and RAP1GAP2 as the core genes, playing essential roles in the TF-miRNA-mRNA network. In the end, we constructed two co-expression modules that highly correlated with AF-related phenotype. Conclusion: In our study, we found critical genes for AF that might help understand the molecular changes in AF.

Role of neutrophil myeloperoxidase in the development and progression of high-altitude pulmonary edema

BackgroundNeutrophil infiltration and hypoxic pulmonary vasoconstriction induced by hypobaric hypoxic stress are vital in high-altitude pulmonary edema (HAPE). Myeloperoxidase (MPO), an important enzyme in neutrophils, is associated with inflammation and oxidative stress and is also involved in the regulation of nitric oxide synthase (NOS), an enzyme that catalyzes the production of the vasodilatory factor nitric oxide (NO). However, the role of neutrophil MPO in HAPE's progression is still uncertain. Therefore, we hypothesize that MPO is involved in the development of HAPE via NOS. MethodsIn Xining, China (altitude: 2260 m), C57BL/6 N wild-type and mpo−/− mice served as normoxic controls, while a hypobaric chamber simulated 7000 m altitude for hypoxia. L-NAME, a nitric oxide synthase (NOS) inhibitor to inhibit NO production, was the experimental drug, and D-NAME, without NOS inhibitory effects, was the control. After measuring pulmonary artery pressure (PAP), samples were collected and analyzed for blood neutrophils, oxidative stress, inflammation, vasoactive substances, pulmonary alveolar-capillary barrier permeability, and lung tissue morphology. ResultsWild-type mice's lung injury scores, permeability, and neutrophil counts rose at 24 and 48 h of hypoxia exposure. Under hypoxia, PAP increased from 12.89 ± 1.51 mmHg under normoxia to 20.62 ± 3.33 mmHg significantly in wild-type mice and from 13.24 ± 0.79 mmHg to 16.50 ± 2.07 mmHg in mpo−/− mice. Consistent with PAP, inducible NOS activity, lung permeability, lung injury scores, oxidative stress response, and inflammation showed more significant increases in wild-type mice than in mpo−/− mice. Additionally, endothelial NOS activity and NO levels decreased more pronouncedly in wild-type mice than in mpo−/− mice. NOS inhibition during hypoxia led to more significant increases in PAP, permeability, and lung injury scores compared to the drug control group, especially in wild-type mice. ConclusionMPO knockout reduces oxidative stress and inflammation to preserve alveolar-capillary barrier permeability and limits the decline in endothelial NOS activity to reduce PAP elevation during hypoxia. MPO inhibition emerges as a prospective therapeutic strategy for HAPE, offering avenues for precise interventions.

Mesenchymal stem cell-derived extracellular vesicles exert pro-angiogenic and pro-lymphangiogenic effects in ischemic tissues by transferring various microRNAs and proteins including ITGa5 and NRP1

Mesenchymal stem cells/stromal cells (MSCs)-derived extracellular vesicles (EVs) mediate pro-regenerative effects in damaged ischemic tissues by regulating angiogenesis. MSCs-EVs modulate functions of cells including endogenous mature cells, progenitors and stem cells, resulting in restoration of blood flow. However, the mechanisms underlying such MSC-EV activity still remain poorly understood. The present study analyzes biological effects of bone marrow (BM) MSC-EVs on endothelial cells (ECs) in ischemic tissues both in in vitro and in vivo conditions and elucidates the molecular mechanisms underlying the tissue repair. MSC-EVs were isolated from murine BM-derived MSCs and their morphological, antigenic and molecular composition regarding protein and microRNA levels were evaluated to examine their properties. Global proteomic analysis demonstrated the presence in MSC-EVs of proteins regulating pro-regenerative pathways, including integrin α5 (Itgα5) and neuropilin-1 (NRP1) involved in lymphangiogenesis. MSC-EVs were also enriched in microRNAs regulating angiogenesis, TGF-β signaling and processes guiding cellular adhesion and interactions with extracellular matrix. The functional effects of MSC-EVs on capillary ECs in vitro included the increase of capillary-like tube formation and cytoprotection under normal and inflammatory conditions by inhibiting apoptosis. Notably, MSC-EVs enhanced also capillary-like tube formation of lymphatic ECs, which may be regulated by Itgα5 and NRP1. Moreover, in a mouse model of critical hind limb ischemia, MSC-EVs increased the recovery of blood flow in ischemic muscle tissue, which was accompanied with increased vascular density in vivo. This pro-angiogenic effect was associated with an increase in nitric oxide (NO) production via endothelial NO-synthase activation in ischemic muscles. Interestingly, MSC-EVs enhanced lymphangiogenesis, which has never been reported before. The study provides evidence on pro-angiogenic and novel pro-lymphangiogenic role of MSC-EVs on ECs in ischemic tissue mediated by their protein and miRNA molecular cargos. The results highlight Itgα5 and NRP1 carried by MSC-EVs as potential therapeutic targets to boost lymphangiogenesis.Graphical

The Angiotensin II Receptor Neprilysin Inhibitor LCZ696 Inhibits the NLRP3 Inflammasome By Reducing Mitochondrial Dysfunction in Macrophages and Alleviates Dextran Sulfate Sodium-induced Colitis in a Mouse Model.

The intracellular sensor protein complex known as the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in regulating inflammatory diseases by overseeing the production of interleukin (IL)-1β and IL-18. Targeting its abnormal activation with drugs holds significant promise for inflammation treatment. This study highlights LCZ696, an angiotensin receptor-neprilysin inhibitor, as an effective suppressor of NLRP3 inflammasome activation in macrophages stimulated by ATP, nigericin, and monosodium urate. LCZ696 also reduces caspase-11 and GSDMD activation, lactate dehydrogenase release, propidium iodide uptake, and the extracellular release of NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) in ATP-activated macrophages, suggesting a potential mitigation of pyroptosis. Mechanistically, LCZ696 lowers mitochondrial reactive oxygen species and preserves mitochondrial integrity. Importantly, it does not significantly impact NLRP3, proIL-1β, inducible nitric oxide synthase, cyclooxygenase-2 expression, or NF-κB activation in lipopolysaccharide-activated macrophages. LCZ696 partially inhibits the NLRP3 inflammasome through the induction of autophagy. In an in vivo context, LCZ696 alleviates NLRP3-associated colitis in a mouse model by reducing colonic expression of IL-1β and tumor necrosis factor-α. Collectively, these findings suggest that LCZ696 holds significant promise as a therapeutic agent for ameliorating NLRP3 inflammasome activation in various inflammatory diseases, extending beyond its established use in hypertension and heart failure treatment.

Bioaccumulation of Microcystin-LR and Induced Physio-Biochemical Changes in Rice (Oryza sativa L.) at Vegetative Stage under Hydroponic Culture Conditions.

Irrigation with water containing a variety of microcystins (MCs) may pose a potential threat to the normal growth of agricultural plants. To investigate the phytotoxicity of MC-LR at environmental concentrations on rice (Oryza sativa L.), the characteristics of uptake and accumulation in plant tissues, as well as a series of key physio-biochemical process changes in leaves of rice seedlings, were measured at concentrations of 0.10, 1.0, 10.0, and 50.0 μg·L-1 in hydroponic nutrient solutions for 7, 15, 20, and 34 days. Results showed that MC-LR could be detected in rice leaves and roots in exposure groups; however, a significant accumulation trend of MC-LR in plants (BCF > 1) was only found in the 0.10 μg·L-1 group. The time-course study revealed a biphasic response of O2•- levels in rice leaves to the exposure of MC-LR, which could be attributed to the combined effects of the antioxidant system and detoxification reaction in rice. Exposure to 1.0-50.0 μg·L-1 MC-LR resulted in significant depletion of GSH and MDA contents in rice leaves at later exposure times (15-34 days). Low MC-LR concentrations promoted nitric oxide synthase (NOS) activity, whereas high concentrations inhibited NOS activity during the later exposure times. The reduced sucrose synthase (SS) activities in rice exposed to MC-LR for 34 days indicated a decrease in the carbon accumulation ability of plants, and therefore may be directly related to the inhibition of plant growth under MC exposure. These findings indicate that the normal physiological status would be disrupted in terrestrial plants, even under exposure to low concentrations of MC-LR.

Dietary N-carbamylglutamate (NCG) supplementation improves the survival, digestive and immunological parameters by promoting ammonia excretion in Chinese mitten crab (Eriocheir sinensis), under ammonia nitrogen stress

Ammonia nitrogen is one of the most common environmental stress factors in aquaculture. The aim of this experiment was to evaluate the effects of ammonia nitrogen stress on ammonia metabolism, digestion and immune function as well as the protective effects of dietary N-carbamylglutamate (NCG) in the Chinese mitten crab (Eriocheir sinensis). Two feeds were used, namely a control feed (regular commercial feed) and an NCG feed (NCG (302.96 ± 4.07) mg/kg added). Subsequently, animals fed by these two feeds were exposed to 30 mg/L or 60 mg/L ammonia nitrogen stress (named A30 or A60) for 21 days, respectively. The rate of hemolymph ammonia excretion was significantly increased in NCG group compared to C (control) group (P < 0.05). Hemolymph ammonia levels were significantly lower in NCG A30 (NCG feed and A30) and NCG A60 (NCG feed and A60) groups compared to A30 (control feed and A30) and A60 (control feed and A60) groups (P < 0.05). Glutamate dehydrogenase and glutamine synthetase activities in the gills and hepatopancreas of NCG A60 group were significantly increased compared with the A60 group, which promoted glutamine synthesis (P < 0.05). The cumulative mortality rate of Eriocheir sinensis in NCG A30 and NCG A60 groups were effectively reduced (P < 0.05). The arginine levels of hepatopancreas were significantly increased in NCG A60 group (P < 0.05). Under ammonia nitrogen stress, NCG significantly increased the activities of trypsin, pepsin, lipase and α-Amylase in NCG feed group, and promoted feeding (P < 0.05). In hemolymph, hepatopancreas and intestine, NCG significantly increased nitric oxide synthase activity, lysozyme and phenol oxidase activities compared to the ammonia nitrogen stress group (P < 0.05). The results indicated that, NCG added in feed could decelerate the toxic effects of ammonia on Eriocheir sinensis by promoting ammonia excretion and accelerating glutamine and endogenous arginine synthesis by metabolism. Moreover, the activity of digestive enzymes and immune-related enzymes is improved.

Dietary (poly)phenols as modulators of the biophysical properties in endothelial cell membranes: its impact on nitric oxide bioavailability in hypertension.

Hypertension is a major contributor to premature death, owing to the associated increased risk of damage to the heart, brain and kidneys. Although hypertension is manageable by medication and lifestyle changes, the risk increases with age. In an increasingly aged society, the incidence of hypertension is escalating, and is expected to increase the prevalence of (cerebro)vascular events and their associated mortality. Adherence to plant-based diets improves blood pressure and vascular markers in individuals with hypertension. Food flavonoids have an inhibitory effect towards angiotensin-converting enzyme (ACE1) and although this effect is greatly diminished upon metabolization, their microbial metabolites have been found to improve endothelial nitric oxide synthase (eNOS) activity. Considering the transmembrane location of ACE1 and eNOS, the ability of (poly)phenols to interact with membrane lipids modulate the cell membrane's biophysical properties and impact on nitric oxide (·NO) synthesis and bioavailability, remain poorly studied. Herein, we provide an overview of the current knowledge on the lipid remodeling of endothelial membranes with age, its impact on the cell membrane's biophysical properties and ·NO permeability across the endothelial barrier. We also discuss the potential of (poly)phenols and other plant-based compounds as key players in hypertension management, and address the caveats and challenges in adopted methodologies.

Modulatory role of nitric oxide in wound healing of potato tubers

IntroductionWounding of potato (Solanum tuberosum L.) tubers affects the postharvest storage qualities and marketability. To mitigate wound-related losses, it is necessary to accelerate wound healing (WH) responses of potato tubers. While role of nitric oxide (NO) in healing of wounded biological tissues is well known, its impact on WH responses of potato tubers has not been examined thoroughly. The aim of this study was to elucidate the potential modulatory role of NO in WH response of potato tubers by determining the activity of key enzymes associated with NO biosynthesis.MethodsUsing a model wounding system, tuber tissue discs were extracted from mini tubers of cv. Russet Burbank to examine their WH responses. Tuber discs were treated with NO related chemicals, such as NO scavenger, nitric oxide synthase (NOS) inhibitor, and NO donors. The effect of these treatments on in vitro production of NO, activity of nitrate reductase, NOS, and phenylalanine ammonia-lyase were determined. The accumulation of suberin polyphenolics (SPP) in wounded parenchyma cells, an indicator of early suberization process, was analyzed histologically.ResultsTreatment of tuber tissues with the higher dose of an NO scavenger (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) at the time of wounding completely ceased SPP accumulation between 0 h to 3 d after wounding. Increased production of NO and enhanced activity of NOS were also observed immediately after wounding of the tuber tissues. The results suggest that NO is a key biological modulator in WH responses of potato tubers and could be optimized as a potential exogenous treatment to counter wound-related losses.

A multicellular brain spheroid model for studying the mechanisms and bioeffects of ultrasound-enhanced drug penetration beyond the blood‒brain barrier

The blood‒brain barrier (BBB) acts as a hindrance to drug therapy reaching the brain. With an increasing incidence of neurovascular diseases and brain cancer metastases, there is a need for an ideal in vitro model to develop novel methodologies for enhancing drug delivery to the brain. Here, we established a multicellular human brain spheroid model that mimics the BBB both architecturally and functionally. Within the spheroids, endothelial cells and pericytes localized to the periphery, while neurons, astrocytes, and microglia were distributed throughout. Ultrasound-targeted microbubble cavitation (UTMC) is a novel noninvasive technology for enhancing endothelial drug permeability. We utilized our three-dimensional (3D) model to study the feasibility and mechanisms regulating UTMC-induced hyperpermeability. UTMC caused a significant increase in the penetration of 10 kDa Texas red dextran (TRD) into the spheroids, 100 µm beyond the BBB, without compromising cell viability. This hyperpermeability was dependent on UTMC-induced calcium (Ca2+) influx and endothelial nitric oxide synthase (eNOS) activation. Our 3D brain spheroid model, with its intact and functional BBB, offers a valuable platform for studying the bioeffects of UTMC, including effects occurring spatially distant from the endothelial barrier.

On the cardiovascular effects mechanism of humic nature macromolecular compounds

Introduction. The search for new drugs to reduce effectively myocardial damage during ischemia and reoxygenation is relevant considering that many pharmacological drugs have a number of limitations for patients and their use is accompanied by negative side effects.Aim: To assess the NO-synthase possible role in the cardiovascular effects mechanism of the standardized active pharmaceutical substance (AFS) of the humic acids (HA) isolated from peat.Material and Methods. The experiments were carried out on the isolated perfused rat heart model using the Langendorff method. We studied the effect of a standardized sample of peat HA at concentrations of 0.001; 0.01; 0.1 mg/ml on coronary perfusion rate and myocardial contractility parameters. To assess the NO-synthase value in the HA effects realization, the enzyme was pre-inhibited using L-NAME (10 µM/L) before the test sample addition.Results. HA sample using contributed to an effective increase in the heart coronary perfusion rate due to the NO-synthase signaling mechanism activation. There was some decrease in contractility and end-diastolic pressure associated with the NOsynthase activation because the enzyme inhibition with L-NAME removed all effects of the test HA sample.Conclusion. The obtained data show to the peat HA have vasodilating properties associated with the NO-synthase activation. The such effect presence indicates on the prospects for further investigation of these compounds cardiotropic properties in the order developing new effective means for improving intracardiac hemodynamics and limiting Ca2+ overload of cardiomyocytes in conditions of ischemia and reperfusion.

Anti-Inflammatory Activity of Vacuum Distillate from Panax ginseng Root on LPS-Induced RAW264.7 Cells.

Panax ginseng has been widely applied as an important herb in traditional medicine to treat numerous human disorders. However, the inflammatory regulation effect of P. ginseng distillate (GSD) has not yet been fully assessed. To determine whether GSD can ameliorate inflammatory processes, a GSD was prepared using the vacuum distillation process for the first time, and the regulation effect on lipopolysaccharide-induced macrophages was assessed. The results showed that GSD effectively inhibited nitric oxide (NO) formation and activation of inducible nitric oxide synthase (iNOS) mRNA in murine macrophage cell, but not cyclooxygenase-2 production. The mRNA expression pattern of tumor necrosis factor alpha and IL-6 were also reduced by GSD. Furthermore, we confirmed that GSD exerted its anti-inflammatory effects by downregulating c-Jun NH2-terminal kinase (JNK) phosphorylation, the extracellular signal-regulated kinase phosphorylation, and signaling pathway of nuclear factor kappa B (NF-κB). Our findings revealed that the inflammatory regulation activity of GSD could be induced by iNOS and NO formation inhibition mediated by regulation of nuclear factor kappa B and p38/JNK MAPK pathways.

Comparative effects of canagliflozin and sitagliptin in chronically ischemic myocardium.

Recent studies demonstrate that sodium-glucose cotransporter 2 inhibitors (SGLT2i) and dipeptidyl peptidase-4 inhibitors (DPP4i), two classes of antidiabetic drugs, are cardioprotective. However, the mechanisms of these benefits and their comparative efficacy remain unclear. We aimed to compare the effects of these antidiabetic agents on cardiac function, perfusion, and microvascular density using a swine model of chronic myocardial ischemia. Chronic myocardial ischemia was induced in Yorkshire swine by ameroid constrictor placement to the left circumflex artery. Two weeks later, pigs were administered vehicle ("CON", 8 pigs), 300 mg SGLT2i canagliflozin, ("CANA", 8 pigs), or 100 mg DPP4i sitagliptin ("SIT", 5 pigs) daily. Five weeks later, pigs were euthanized. Cardiac function, perfusion, collateralization, and protein expression were determined by pressure-volume catheter, microsphere analysis, immunofluorescence, and immunoblotting, respectively. Compared with SIT, CANA was associated with improved stroke volume and cardiac output, with a trend towards reduced left ventricular stiffness. Both CANA and SIT trended towards improved perfusion compared to CON, but there were no differences between the two treatment groups. SIT was associated with improved capillary density with a trend towards improved arteriolar density compared to CANA. Both CANA and SIT were associated with increased expression of vascular endothelial cadherin compared to CON, without differences in treatment groups. SIT pigs had decreased 5' adenosine monophosphate-activated protein kinase activation compared to CON and CANA. There was a trend towards increased endothelial nitric oxide synthase activation in the SIT group compared to CON. There were no differences in activation of extracellular signal-regulated kinase 1/2 across groups. In the setting of chronic myocardial ischemia, canagliflozin is associated with improved cardiac function compared to sitagliptin, with similar effects on perfusion despite differences in microvascular collateralization.

Scutellaria Baicalensis Georgi Stem and Leaf Flavonoids Ameliorate the Learning and Memory Impairment in Rats Induced by Okadaic Acid.

The objective of this study is to explore the impact and underlying mechanism of Scutellaria baicalensis Georgi stem and leaf flavonoids (SSFs) on cognitive impairment caused by intracerebroventricular injection of okadaic acid (OA) in rats. An experimental model of Alzheimer's disease (AD) was induced in rats by intracerebroventricular injection of OA, resulting in memory impairment. The Morris water maze test was employed to confirm the successful establishment of the memory impairment model. The rats that exhibited significant memory impairment were randomly divided into different groups, including a model group, three SSFs dose groups (25, 50, and 100 mg/kg), and a positive control group treated with Ginkgo biloba tablets (GLT) at a dose of 200 mg/kg. To evaluate the learning and memory abilities of the rats, the Morris water maze test was conducted. Hematoxylin-eosin (HE) staining was used to observe any morphological changes in neurons. Immunohistochemistry (IHC) was performed to measure the expression of choline acetyltransferase (ChAT) protein. Western blotting (WB) was utilized to assess the phosphorylation levels of tau protein at Ser262 and Ser396. The activities of inducible nitric oxide synthase (iNOS) and constitutive nitric oxide synthase (cNOS) were quantified using ultraviolet spectrophotometry. The levels of inflammatory factors, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), were measured using ELISA. In rats, the administration of OA via intracerebroventricular injection resulted in cognitive impairment, neuropathological changes, and alterations in protein expression and activity levels. Specifically, the protein expression of ChAT was significantly reduced (P<0.01), while the phosphorylation levels of tau protein at Ser262 and Ser396 were significantly increased (P<0.01). Moreover, iNOS activity in the hippocampus and cerebral cortex exhibited a significant increase (P<0.01), whereas cNOS activity showed a decrease (P<0.05). Furthermore, the levels of IL-1β and TNF-α in the cerebral cortex were elevated (P<0.01), while the level of IL-6 was decreased (P<0.05). The administration of three doses of SSFs and GLT to rats exhibited varying degrees of improvement in the aforementioned pathological alterations induced by OA. SSFs demonstrated the ability to enhance cognitive function and mitigate memory deficits in rats following intracerebroventricular injection of OA. This beneficial effect may be attributed to the modulation of ChAT protein expression, tau hyperphosphorylation, NOS activity, and inflammatory cytokine levels by SSFs.

High iNOS and IL-1β immunoreactivity are features of colitis-associated colorectal cancer tumors, but fail to predict 5-year survival.

Inflammatory bowel disease (IBD; mainly ulcerative colitis and Crohn's disease) is associated with the development of colorectal cancer (CRC) referred to as colitis-associated colorectal cancer (CAC). In inflammatory flares of IBD, the production of luminal nitric oxide (NO) increases due to the increased inducible nitric oxide synthase (iNOS) activity in inflamed tissue. It is believed that iNOS parallels pro-inflammatory interleukin-1β (IL-1β). How these biomarkers relate to CAC pathogenesis or survival is unknown. The primary aim of this study was to investigate iNOS and IL-1β immunoreactivity in CAC tumors in comparison with CRC and normal colonic mucosa, and the secondary aim was to determine if immunoreactivity correlates with 5-year survival of CAC. Immunohistochemistry was performed on tissue sections as follows: CAC (n = 59); sporadic CRC (sCRC) (n = 12); colonic mucosa >2 cm outside sCRC margin (normal mucosa) (n = 22); paracancerous IBD (pIBD) (n = 12). The expression of iNOS and IL-1β was quantified separately for epithelium and stroma. Data were evaluated using the Mann-Whitney U-test and the log-rank test for 5-year Kaplan-Meier survival curves. Results were compared with online mRNA databases. Immunoreactivity occurred predominantly in epithelial cells and to lesser extent in stroma. Compared with normal mucosa, immunoreactivity for iNOS (P < 0.01) and IL-1β (P < 0.005) was higher in CAC epithelium. In CAC stroma, iNOS immunoreactivity was lower than normal mucosa (P < 0.001), whereas IL-1β was higher (P < 0.05). Immunoreactivity differences of iNOS or IL-1β among CAC patients failed to correlate with 5-year survival. These findings were supported by online mRNA databases. Consistent with high NO production in IBD, there is more iNOS in CAC epithelium, albeit not in stroma. This immunoreactivity difference exists for IL-1β in both epithelium and stroma. The intervention of arginine or iNOS activity for CAC chemotherapy is not straightforward.

The Importance of Nitric Oxide and Oxidative Stress in Atrial High-Rate Episodes in Patients with Cardiac Devices.

Atrial High Rate Episodes (AHRE) are subclinical atrial tachyarrhythmias detectable by cardiac implantable electronic devices (CIEDs). AHREs have been associated with an increased risk of developing atrial fibrillation (AF), thromboembolism, cardiovascular and cerebrovascular events, and mortality. Although recent studies have assessed the value of oxidative stress markers in patients with AF, the relationships between AHRE and oxidative stress markers, including nitric oxide, has not yet been elucidated. This study aims to investigate the relationship between these markers and AHRE. This prospective, cross-sectional study comprised 180 patients with CIEDs. The study population was divided into two groups based on the presence (n = 78) and absense (n = 102) of AHRE to analyze its association with biomarkers. The AHRE (+) group was significantly older, had a higher prevalence of hypertension, higher NT-proBNP (508.8 ± 249 pg/mL vs. 415.3 ± 292.1; P = 0.037), MDA levels (20.9 ± 4.1 μmol/L vs. 19.1 ± 3.1 μmol/L; P = 0.006), and iNOS activity (1,935.9 ± 326.1 pg/mL vs. 1,677.4 ± 363.2 pg/mL; P < 0.001). Logistic regression analysis identified age, hypertension, MDA (odds ratio [OR]: 1.131, 95%CI: 1.009 - 1.268, P = 0.035), inducible nitric oxide synthase (iNOS) activity (OR = 1.002, 95% CI = 1.001 - 1.003, P < 0.001), and endothelial nitric oxide synthase (eNOS) activity (OR = 0.990, 95% CI = 0.986 - 0.984, P < 0.001) as independent predictors of AHRE. The study findings indicated that plasma levels of NT-proBNP, MDA, nitric oxide, and the expression of iNOS and eNOS were significantly associated with AHRE. Moreover, elevated plasma MDA concentrations, increased iNOS activity, and decreased eNOS activity were identified as independent predictors of AHRE.

Influence of pallet rich plasma, quercetin and their combination on activity of nitric oxide cycle enzymes in nasal mucosa of patients with atrophic rhinitis.

Aim: To study the general activity of NO synthases (gNOS), the activity of inducible and constitutive isoforms of NO synthase, the activity of arginases, and the concentration of nitrites in the nasal mucosa under the conditions of local treatment of chronic atrophic rhinitis (AR) with quercetin and platelet-rich plasma (PRP therapy).. Materials and Methods: The study was conducted on 118 patients divided into two groups: control (n=20) and experimental (patients with AR, n=98). Experimental group was divided into 4 subgroups: standard treatment (n=29), PRP therapy (6 injections for 28 day course, n=19), Quercetin (40 mg 3 times a day for 28 days, n=26) and PRP+Quercetin (n=24) groups. Results: Standard therapy of SaR increases gNOS by 278.38% and arginase activity increases by 222.73%. PRP therapy increases gNOS by 211.43% and arginase by 540.91%. Quercetin elevates gNOS by 108.33% and arginase by 250%. PRP therapy and quercetin increases gNOS by 146.15% and arginase by 536.36%. Conclusions: The use of standard therapy of SaR and addition of PRP therapy, quercetin and their combination effectively restores the production of nitric oxide and the arginase activity in the nasal mucosa.