Nitric oxide, a protective molecule in the cardiovascular system

Nitric Oxide-Releasing Porous Coating with Antibacterial Activity and Blood Compatibility

Nitric oxide (NO)-releasing coating is promising to enhance the biocompatibility of medical devices. In this study, polyurethane (PU) and S-nitrosated keratin (KSNO) were dissolved with dimethyl sulfoxide (DMSO) and tetrahydrofuran (THF) to prepare a coating solution. This solution is facile to form a porous coating on various substrates based on solvent-evaporation-induced phase separation (SEIPS). The coating could continuously release NO up to 200 h in the presence of ascorbic acid (Asc). In addition, the coating could accelerate endothelialization by promoting the viability of human umbilical vein endothelial cells (HUVECs) while inhibiting the proliferation of human umbilical artery smooth muscle cells (HUASMCs). Furthermore, the coating had good antibacterial activity and blood compatibility. Taken together, this universal coating provides wider potential applications in the field of cardiovascular implants.

The Role of Stem Cells as Therapeutics for Ischaemic Stroke

Stroke remains one of the leading causes of death and disability worldwide. Current reperfusion treatments for ischaemic stroke are limited due to their narrow therapeutic window in rescuing ischaemic penumbra. Stem cell therapy offers a promising alternative. As a regenerative medicine, stem cells offer a wider range of treatment strategies, including long-term intervention for chronic patients, through the reparation and replacement of injured cells via mechanisms of differentiation and proliferation. The purpose of this review is to evaluate the therapeutic role of stem cells for ischaemic stroke. This paper discusses the pathology during acute, subacute, and chronic phases of cerebral ischaemic injury, highlights the mechanisms involved in mesenchymal, endothelial, haematopoietic, and neural stem cell-mediated cerebrovascular regeneration, and evaluates the pre-clinical and clinical data concerning the safety and efficacy of stem cell-based treatments. The treatment of stroke patients with different types of stem cells appears to be safe and efficacious even at relatively higher concentrations irrespective of the route and timing of administration. The priming or pre-conditioning of cells prior to administration appears to help augment their therapeutic impact. However, larger patient cohorts and later-phase trials are required to consolidate these findings.

Morphometric aspects of remodeling of the arterial bed of the testicles in post- resection portal and pulmonary hypertensions

OBJECTIVE

Aim: To perform a morphometric analysis of the features of vascular remodeling of the arterial bed of the testicles in post-resection portal and pulmonary hypertension.

PATIENTS AND METHODS

Materials and Methods: The testes of 54 white rats were studied, which were divided into groups: 1st included 16 intact animals, 2nd - 20 rats with pulmonary hypertension, 3rd - 18 individuals with post-resection portal hypertension. Postresection pulmonary hypertension was modeled by right-sided pulmonectomy. Postresection portal hypertension was simulated by removing 58.1 % of the liver parenchyma.

RESULTS

Results: The outer diameter of the small-caliber arteries of the left testicle increased by 3.4% (p<0.05) in post-resection arterial pulmonary hypertension, and by 2.9% in post-resection portal hypertension. The inner diameter of the small-caliber arteries of the left testicle decreased by 7.7% (p<0.001) in pulmonary heart disease, and by 6.5% (p<0.01) in post-resection portal hypertension. The Kernogan index decreased by 23.0% (p<0.001), the Vogenvoort index increased by 1.26 times. In case of post-resection portal hypertension, the Kernogan index decreased by 19.0% (p<0.001) and the Wogenvoort's index increased by 1.19 times. The relative volume of damaged endotheliocytes in the small-caliber arteries of the left testis increased 20.6 times (p<0.001) in pulmonary heart disease, and increased 16.3 times (p<0.001) in post-resection portal hypertension.

CONCLUSION

Conclusions: Portal and pulmonary hypertension lead to pronounced remodeling of the arterial bed of the testicles, which is characterized by thickening of the arterial wall, narrowing of their lumen, significant changes in Wogenvoort and Kernogan indexes, atrophy, dystrophy, and necrobiosis of endotheliocytes.

Polysaccharide-based hydrogels for medical devices, implants and tissue engineering: A review

Hydrogels are highly biocompatible biomaterials composed of crosslinked three-dimensional networks of hydrophilic polymers. Owing to their natural origin, polysaccharide-based hydrogels (PBHs) possess low toxicity, high biocompatibility and demonstrate in vivo biodegradability, making them great candidates for use in various biomedical devices, implants, and tissue engineering. In addition, many polysaccharides also show additional biological activities such as antimicrobial, anticoagulant, antioxidant, immunomodulatory, hemostatic, and anti-inflammatory, which can provide additional therapeutic benefits. The porous nature of PBHs allows for the immobilization of antibodies, aptamers, enzymes and other molecules on their surface, or within their matrix, potentiating their use in biosensor devices. Specific polysaccharides can be used to produce transparent hydrogels, which have been used widely to fabricate ocular implants. The ability of PBHs to encapsulate drugs and other actives has been utilized for making neural implants and coatings for cardiovascular devices (stents, pacemakers and venous catheters) and urinary catheters. Their high water-absorption capacity has been exploited to make superabsorbent diapers and sanitary napkins. The barrier property and mechanical strength of PBHs has been used to develop gels and films as anti-adhesive formulations for the prevention of post-operative adhesion. Finally, by virtue of their ability to mimic various body tissues, they have been explored as scaffolds and bio-inks for tissue engineering of a wide variety of organs. These applications have been described in detail, in this review.

Advances in Fabrication Technologies for the Development of Next-Generation Cardiovascular Stents

Coronary artery disease is the most prevalent cardiovascular disease, claiming millions of lives annually around the world. The current treatment includes surgically inserting a tubular construct, called a stent, inside arteries to restore blood flow. However, due to lack of patient-specific design, the commercial products cannot be used with different vessel anatomies. In this review, we have summarized the drawbacks in existing commercial metal stents which face problems of restenosis and inflammatory responses, owing to the development of neointimal hyperplasia. Further, we have highlighted the fabrication of stents using biodegradable polymers, which can circumvent most of the existing limitations. In this regard, we elaborated on the utilization of new fabrication methodologies based on additive manufacturing such as three-dimensional printing to design patient-specific stents. Finally, we have discussed the functionalization of these stent surfaces with suitable bioactive molecules which can prove to enhance their properties in preventing thrombosis and better healing of injured blood vessel lining.

Acute sublethal exposure to ethiprole impairs physiological and oxidative status in the Neotropical fish Astyanax altiparanae

Ethiprole, a phenylpyrazole insecticide, has been increasingly used in the Neotropical region to control stink bug pests in soybean and maize fields. However, such abrupt increases in use may have unintended effects on non-target organisms, including those inhabiting freshwater ecosystems. Here, we evaluated the effects of acute (96 h) sublethal exposure to ethiprole (up to 180 μg/L, which is equivalent to 0.013% of the recommended field dose) on biomarkers of stress in the gills, liver, and muscle of the Neotropical fish Astyanax altiparanae. We further recorded potential ethiprole-induced effects on the structural histology of A. altiparanae gills and liver. Our results showed that ethiprole exposure increased glucose and cortisol levels in a concentration-dependent manner. Ethiprole-exposed fish also exhibited higher levels of malondialdehyde and greater activity of antioxidant enzymes, such as glutathione-S-transferase and catalase, in both gills and liver. Furthermore, ethiprole exposure led to increased catalase activity and carbonylated protein levels in muscle. Morphometric and pathological analyses of the gills revealed that increasing ethiprole concentration resulted in hyperemia and loss of integrity of the secondary lamellae. Similarly, histopathological analysis of the liver demonstrated higher prevalence of necrosis and inflammatory infiltrates with increasing ethiprole concentration. Altogether, our findings demonstrated that sublethal exposure to ethiprole can trigger a stress response in non-target fish species, which may lead to potential ecological and economic imbalances in Neotropical freshwater systems.

l-Arginine/nitric oxide pathway and oxidative stress in adults with ADHD: Effects of methylphenidate treatment

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a mental disorder that was once thought to occur only in children. Meanwhile, it is known that adults can also be affected. The first-line drug in children and adults to treat symptoms of inattention, impulsivity, lack of self-regulation, and hyperactivity is methylphenidate (MPH). Known adverse effects of MPH include cardiovascular problems, such as elevated blood pressure and heart rate. Therefore, biomarkers to monitor potential cardiovascular side effects of MPH are needed. The l-Arginine/Nitric oxide (Arg/NO) pathway is involved in noradrenaline and dopamine release as well as in normal cardiovascular functioning and is therefore a prime candidate for the search of biomarkers. The aim of the present study was to investigate the Arg/NO pathway as well as oxidative stress in adult ADHD patients in plasma and urine and the potential influence of MPH medication.

METHODS

In plasma and urine samples of 29 adults with ADHD (39.2 ± 10.9 years) and 32 healthy adults serving as controls (CO) (38.0 ± 11.6 years) the major NO metabolites nitrite and nitrate, Arg, the NO synthesis inhibitor asymmetric dimethylarginine (ADMA) and its major urinary metabolite dimethylamine (DMA) as well as malondialdehyde (MDA) were measured by gas chromatography-mass spectrometry.

RESULTS

Of the 29 patients with ADHD 14 were currently without MPH treatment (-MPH) and 15 were treated with MPH (+MPH). Plasma nitrate concentrations were significantly higher in patients not treated with MPH vs. CO (-MPH 60.3 μM [46.2-76.0] vs. CO 44.4 μM [35.0-52.7]; p = 0.002), while plasma nitrite tended to be higher in -MPH patients (2.77 μM [2.26-3.27]) vs. CO (2.13 μM [1.50-2.93]; p = 0.053). Additionally, plasma creatinine concentrations were significantly different, with -MPH showing significantly higher concentrations than the other two groups (-MPH 141 μM [128-159]; +MPH 96.2 μM [70.2-140]; Co 75.9 μM [62.0-94.7]; p < 0.001). Urinary creatinine excretion tended to be lowest in -MPH group vs. +MPH and CO (-MPH 11.4 ± 8.88 mM; +MPH 20.7 ± 9.82 mM; 16.6 ± 7.82 mM; p = 0.076). None of the other metabolites, including MDA, a marker of oxidative stress, showed a difference between the groups.

CONCLUSION

Adult patients with ADHD, who are not treated with MPH (-MPH), showed varied Arg/NO pathway, but Arg bioavailability seemed to be consistent over the groups. Our findings imply that urinary reabsorption may be increase and/or excretion of nitrite and nitrate may be decreased in ADHD, resulting in an increase in the plasma concentration of nitrite. MPH seems to partially reverse these effects by not yet known mechanisms, and does not affect oxidative stress.

Advances in Nitric Oxide-Releasing Hydrogels for Biomedical Applications

Hydrogels provide a plethora of advantages to biomedical treatments due to their highly hydrophilic nature and tissue-like mechanical properties. Additionally, the numerous and widespread endogenous roles of nitric oxide have led to an eruption in research developing biomimetic solutions to the many challenges the biomedical world faces. Though many design factors and fabrication details must be considered, utilizing hydrogels as nitric oxide delivery vehicles provides promising materials in several applications. Such applications include cardiovascular therapy, vasodilation and angiogenesis, antimicrobial treatments, wound dressings, and stem cell research. Herein, a recent update on the progress of NO-releasing hydrogels is presented in depth. In addition, considerations for the design and fabrication of hydrogels and specific biomedical applications of nitric oxide-releasing hydrogels are discussed.

Nucleotide Messenger Signaling of Staphylococci in Responding to Nitric Oxide - Releasing Biomaterials

Nitric oxide (NO) releasing biomaterials are a promising approach against medical device associated microbial infection. In contrast to the bacteria-killing effects of NO at high concentrations, NO at low concentrations serves as an important signaling molecule to inhibit biofilm formation or disperse mature biofilms by regulating the intracellular nucleotide second messenger signaling network such as cyclic dimeric guanosine monophosphate (c-di-GMP) for many Gram-negative bacterial strains. However, Gram-positive staphylococcal bacteria are the most commonly diagnosed microbial infections on indwelling devices, but much less is known about the nucleotide messengers and their response to NO as well as the mechanism by which NO inhibits biofilm formation. This study investigated the cyclic nucleotide second messengers c-di-GMP, cyclic dimeric adenosine monophosphate (c-di-AMP), and cyclic adenosine monophosphate (cAMP) in both Staphylococcus aureus (S. aureus) Newman D2C and Staphylococcus epidermidis (S. epidermidis) RP62A after incubating with S-nitroso-N-acetylpenicillamine (SNAP, NO donor) impregnated polyurethane (PU) films. Results demonstrated that NO release from the polymer films significantly reduced the c-di-GMP levels in S. aureus planktonic and sessile cells, and these bacteria showed inhibited biofilm formation. However, the effect of NO release on c-di-GMP in S. epidermidis was weak, but rather, S. epidermidis showed significant reduction in c-di-AMP levels in response to NO release and also showed reduced biofilm formation. Results strongly suggest that NO regulates the nucleotide second messenger signaling network in different ways for these two bacteria, but for both bacteria, these changes in signaling affect the formations of biofilms. These findings provide cues to understand the mechanism of Staphylococcus biofilm inhibition by NO and suggest novel targets for antibiofilm interventions.

Endothelial Histone Deacetylase 1 Activity Impairs Kidney Microvascular NO Signaling in Rats fed a High Salt Diet

Aim

We aimed to identify new mechanisms by which a high salt diet (HS) decreases NO production in kidney microvascular endothelial cells. Specifically, we hypothesized HS impairs NO signaling through a histone deacetylase 1 (HDAC1)-dependent mechanism.

Methods

Male Sprague Dawley rats were fed normal salt diet (NS; 0.49% NaCl) or high salt diet (4% NaCl) for two weeks. NO signaling was assessed by measuring L-NAME induced vasoconstriction of the afferent arteriole using the blood perfused juxtamedullary nephron (JMN) preparation. In this preparation, kidneys were perfused with blood from a donor rat on a matching or different diet to that of the kidney donor. Kidney endothelial cells were isolated with magnetic activated cell sorting and HDAC1 activity was measured.

Results

We found that HS impaired NO signaling in the afferent arteriole. This was restored by inhibition of HDAC1 with MS-275. Consistent with these findings, HDAC1 activity was increased in kidney endothelial cells. We further found the loss of NO to be dependent upon the diet of the blood donor rather than the diet of the kidney donor and the plasma from HS fed rats to be sufficient to induce dysfunction suggesting a humoral factor, we termed Plasma Derived Endothelial-dysfunction Mediator (PDEM), mediates the endothelial dysfunction. The antioxidants, PEG-SOD and PEG-catalase, as well as the NOS cofactor, tetrahydrobiopterin, restored NO signaling.

Conclusion

We conclude that HS activates endothelial HDAC1 through PDEM leading to decreased NO signaling. This study provides novel insights into the molecular mechanisms by which a HS decreases renal microvascular endothelial NO signaling.

The Inhibition Effects of Sodium Nitroprusside on the Survival of Differentiated Neural Stem Cells through the p38 Pathway

Nitric oxide (NO) is a crucial factor in regulating neuronal development. However, certain effects of NO are complex under different physiological conditions. In this study, we used differentiated neural stem cells (NSCs), which contained neural progenitor cells, neurons, astrocytes, and oligodendrocytes, to observe the physiological effects of sodium nitroprusside (SNP) on the early developmental stage of the nervous system. After SNP treatment for 24 h, the results showed that SNP at 100 μM, 200 μM, 300 μM, and 400 μM concentrations resulted in reduced cell viability and increased cleaved caspase 3 levels, while no significant changes were found at 50 μM. There were no effects on neuronal differentiation in the SNP-treated groups. The phosphorylation of p38 was also significantly upregulated with SNP concentrations of 100 μM, 200 μM, 300 μM, and 400 μM, with no changes for 50 μM concentration in comparison with the control. We also observed that the levels of phosphorylation increased with the increasing concentration of SNP. To further explore the possible role of p38 in SNP-regulated survival of differentiated NSCs, SB202190, the antagonist of p38 mitogen-activated protein kinase, at a concentration of 10 mM, was pretreated for 30 min, and the ratio of phosphorylated p38 was found to be decreased after treatment with SNP. Survival and cell viability increased in the SB202190 and SNP co-treated group. Taken together, our results suggested that p38 is involved in the cell survival of NSCs, regulated by NO.

The proteins derived from platelet-rich plasma improve the endothelialization and vascularization of small diameter vascular grafts

Vascular transplantation has become an ideal substitute for heart and peripheral vascular bypass therapy and tissue-engineered vascular grafts (TEVGs) present an attractive potential solution for vascular surgery. However, small diameter (Ф < 6 mm) vascular do not have ideal TEVGs for clinical use. Platelet-rich plasma (PRP), a key source of bioactive molecules, has been confirmed to promote tissue repair and regeneration. In this study, we prepared PRP-loaded TEVGs (PRP-TEVGs) by electrospinning, investigated the characterization of TEVGs, and verified the effect of PRP-TEVGs in vivo and in vitro experiments. The results suggested that PRP-TEVGs had good biocompatibility, released growth factors stably, promoted cell proliferation and migration significantly, up-regulated the expression of endothelial NO synthase (eNOS) in functional vascular endothelial cells (VECs), and maintained the stability of the endothelial structure. In vivo experiments suggest that PRP can promote rapid endothelialization and reconstruction of TEVGs. Overall, this finding indicated that PRP could promote the rapid vascular endothelialization of small-diameter TEVGs by improving contractile vascular smooth muscle cells (VSMCs) regeneration, and maintaining the integrity and functionality of VECs.

Tannic Acid-Assisted Immobilization of Copper(II), Carboxybetaine, and Argatroban on Poly(ethylene terephthalate) Mats for Synergistic Improvement of Blood Compatibility and Endothelialization

Due to thrombosis and intimal hyperplasia, small-diameter vascular grafts have poor long-term patency. A combination strategy based on nitric oxide (NO) and anticoagulants has the potential to address those issues. In this study, poly(ethylene terephthalate) (PET) mats were prepared by electrospinning and coated with tannic acid (TA)/copper ion complexes. The chelated copper ions endowed the mats with sustained NO generation by catalytic decomposition of endogenous S-nitrosothiol. Subsequently, zwitterionic carboxybetaine acrylate (CBA) and argatroban (AG) were immobilized on the mats. The introduced AG and CBA had synergistic effects on the improvement of blood compatibility, resulting in reduced platelet adhesion and prolonged blood clotting time. The biocomposite mats selectively promoted the proliferation and migration of human umbilical vein endothelial cells while inhibiting the proliferation and migration of human umbilical arterial smooth muscle cells under physiological conditions. In addition, the prepared mats exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. Collectively, the prepared mats hold great promise as artificial small-diameter vascular grafts.

Coronary endothelial dysfunction: from pathogenesis to clinical implications

Endothelial dysfunction (ED) has a substantial role in the pathogenesis of atherosclerosis and other vascular diseases. Multiple risk factors, including smoking, hyperlipiadaemia and diabetes, can have associated ED, which is correlated with cardiac events. Measurement of coronary artery endothelial function requires the use of invasive techniques to assess both epicardial coronary artery and microvascular beds. Peripheral vascular techniques and endothelial biomarkers can be used to indirectly assess coronary ED. In this review of coronary artery ED, we discuss the current state of the field, the techniques used to measure ED and its clinical implications.

Recent Advances in Nano-Formulations for Skin Wound Repair Applications

Skin injuries caused by accidents and acute or chronic diseases place a heavy burden on patients and health care systems. Current treatments mainly depend on preventing infection, debridement, and hemostasis and on supplementing growth factors, but patients will still have scar tissue proliferation or difficulty healing and other problems after treatment. Conventional treatment usually focuses on a single factor or process of wound repair and often ignores the influence of the wound pathological microenvironment on the final healing effect. Therefore, it is of substantial research value to develop multifunctional therapeutic methods that can actively regulate the wound microenvironment and reduce the oxidative stress level at the wound site to promote the repair of skin wounds. In recent years, various bioactive nanomaterials have shown great potential in tissue repair and regeneration due to their properties, including their unique surface interface effect, small size effect, enzyme activity and quantum effect. This review summarizes the mechanisms underlying skin wound repair and the defects in traditional treatment methods. We focus on analyzing the advantages of different types of nanomaterials and comment on their toxicity and side effects when used for skin wound repair.

Facile fabrication of copper-incorporating poly(ε-caprolactone)/keratin mats for tissue-engineered vascular grafts with the potential of catalytic nitric oxide generation

Tissue-engineered vascular grafts (TEVGs) provide a new alternative for vascular construction. Nitric oxide (NO) is capable of promoting vascular tissue regeneration and reducing restenosis caused by vascular implantation. Therefore, in situ production of NO by catalytic decomposition of the endogenous donor is a promising strategy to fabricate a TEVG. In this study, poly(ε-caprolactone) (PCL) was first electrospun with keratin (Ker) to afford PCL/Ker mats and then incorporated with Cu(II) ions through multiple interactions. This strategy is very simple, green, and facile. Particularly, the incorporated Cu(II) ions were partially reduced to Cu(I) ions due to the reducibility of keratin. The chelated copper ions were expected to catalyze the generation of NO from endogenous S-nitrosothiol (RSNO). As a result, PCL/Ker-Cu mats selectively accelerated the adhesion, migration, and growth of human umbilical vein endothelial cells (HUVECs), while inhibiting the proliferation of human umbilical artery smooth muscle cells (HUASMCs). Furthermore, these mats exhibited excellent blood compatibility and significant antibacterial activity. Vascular implantation in vivo indicated that the tubular mats could inhibit thrombus formation and retain patency for 3 months after implantation in the rabbit carotid artery. More importantly, vascular remodeling was observed during follow-up, including a complete endothelium and smooth muscle layer. Taken together, the PCL/Ker-Cu mats have great potential application in vascular tissue regeneration.

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

Nitric oxide and long-term outcomes after kidney transplantation: Results of the TransplantLines cohort study

Impaired endogenous nitric oxide (NO) production may contribute to graft failure and premature mortality in kidney transplant recipients (KTR). We investigated potential associations of 24-h urinary NOx (NO₃^- + NO₂^-) excretion (uNOx) with long-term outcomes. uNOx was determined by HPLC and GC-MS in 698 KTR and in 132 kidney donors before and after donation. Additionally, we measured urinary nitroso species (RXNO) by gas-phase chemiluminescence. Median uNOx was lower in KTR compared to kidney donors (688 [393-1076] vs. 1301 [868-1863] before donation and 1312 [982-1853] μmol/24h after donation, P < 0.001). During median follow-up of 5.4 [4.8-6.1] years, 150 KTR died (61 due to cardiovascular disease) and 83 experienced graft failure. uNOx was inversely associated with all-cause mortality (HR per doubling of uNOx: 0.84 [95% CI 0.75-0.93], P < 0.001) and cardiovascular mortality (HR 0.78 [95% CI 0.67-0.92], P = 0.002). The association of uNOx with graft failure was lost when adjusted for renal function (HR per doubling of uNOx: 0.89 [95% CI 0.76-1.05], P = 0.17). There were no significant associations of urinary RXNO with outcomes. Our study suggests that KTR have lower NO production than healthy subjects and that lower uNOx is associated with a higher risk of all-cause and cardiovascular mortality.

NO in Viral Infections: Role and Development of Antiviral Therapies

Nitric oxide is a ubiquitous signaling radical that influences critical body functions. Its importance in the cardiovascular system and the innate immune response to bacterial and viral infections has been extensively investigated. The overproduction of NO is an early component of viral infections, including those affecting the respiratory tract. The production of high levels of NO is due to the overexpression of NO biosynthesis by inducible NO synthase (iNOS), which is involved in viral clearance. The development of NO-based antiviral therapies, particularly gaseous NO inhalation and NO-donors, has proven to be an excellent antiviral therapeutic strategy. The aim of this review is to systematically examine the multiple research studies that have been carried out to elucidate the role of NO in viral infections and to comprehensively describe the NO-based antiviral strategies that have been developed thus far. Particular attention has been paid to the potential mechanisms of NO and its clinical use in the prevention and therapy of COVID-19.

Characterization of the L-Arginine/Nitric Oxide Pathway and Oxidative Stress in Pediatric Patients with Atopic Diseases

Introduction: L-Arginine (Arg) is a semi-essential amino acid. Constitutive and inducible nitric oxide synthase (NOS) isoforms convert Arg to nitric oxide (NO), a potent vaso- and bronchodilator with multiple biological functions. Atopic dermatitis (AD) and bronchial asthma (BA) are atopic diseases affecting many children globally. Several studies analyzed NO in airways, yet the systemic synthesis of NO in AD and BA in children with BA, AD or both is elusive. Methods: In a multicenter study, blood and urine were obtained from 130 of 302 participating children for the measurement of metabolites of the Arg/NO pathway (BA 31.5%; AD 5.4%; AD + BA 36.1%; attention deficit hyperactivity disorder (ADHD) 12.3%). In plasma and urine amino acids Arg and homoarginine (hArg), both substrates of NOS, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), both inhibitors of NOS, dimethylamine (DMA), and nitrite and nitrate, were measured by gas chromatography–mass spectrometry. Malondialdehyde (MDA) was measured in plasma and urine samples to evaluate possible effects of oxidative stress. Results: There were no differences in the Arg/NO pathway between the groups of children with different atopic diseases. In comparison to children with ADHD, children with AD, BA or AD and BA had higher plasma nitrite (p < 0.001) and nitrate (p < 0.001) concentrations, suggesting higher systemic NO synthesis in AD and BA. Urinary excretion of DMA was also higher (p = 0.028) in AD and BA compared to patients with ADHD, suggesting elevated ADMA metabolization. Discussion/Conclusion: The Arg/NO pathway is activated in atopic diseases independent of severity. Systemic NO synthesis is increased in children with an atopic disease. Plasma and urinary MDA levels did not differ between the groups, suggesting no effect of oxidative stress on the Arg/NO pathway in atopic diseases.

Taurine and Its Derivatives: Analysis of the Inhibitory Effect on Platelet Function and Their Antithrombotic Potential

Taurine is a semi-essential, the most abundant free amino acid in the human body, with a six times higher concentration in platelets than any other amino acid. It is highly beneficial for the organism, has many therapeutic actions, and is currently approved for heart failure treatment in Japan. Taurine has been repeatedly reported to elicit an inhibitory action on platelet activation and aggregation, sustained by in vivo, ex vivo, and in vitro animal and human studies. Taurine showed effectiveness in several pathologies involving thrombotic diathesis, such as diabetes, traumatic brain injury, acute ischemic stroke, and others. As human prospective studies on thrombosis outcome are very difficult to carry out, there is an obvious need to validate existing findings, and bring new compelling data about the mechanisms underlying taurine and derivatives antiplatelet action and their antithrombotic potential. Chloramine derivatives of taurine proved a higher stability and pronounced selectivity for platelet receptors, raising the assumption that they could represent future potential antithrombotic agents. Considering that taurine and its analogues display permissible side effects, along with the need of finding new, alternative antithrombotic drugs with minimal side effects and long-term action, the potential clinical relevance of this fascinating nutrient and its derivatives requires further consideration.

A tough nitric oxide-eluting hydrogel coating suppresses neointimal hyperplasia on vascular stent

Vascular stent is viewed as one of the greatest advancements in interventional cardiology. However, current approved stents suffer from in-stent restenosis associated with neointimal hyperplasia or stent thrombosis. Herein, we develop a nitric oxide-eluting (NOE) hydrogel coating for vascular stents inspired by the biological functions of nitric oxide for cardiovascular system. Our NOE hydrogel is mechanically tough and could selectively facilitate the adhesion of endothelial cells. Besides, it is non-thrombotic and capable of inhibiting smooth muscle cells. Transcriptome analysis unravels the NOE hydrogel could modulate the inflammatory response and induce the relaxation of smooth muscle cells. In vivo study further demonstrates vascular stents coated with it promote rapid restoration of native endothelium, and persistently suppress inflammation and neointimal hyperplasia in both leporine and swine models. We expect such NOE hydrogel will open an avenue to the surface engineering of vascular implants for better clinical outcomes.

Neointimal hyperplasia and stent thrombosis remain issues with vascular stents. Here, the authors report on the development of a nitric oxide releasing hydrogel which allows for endothelialisation of the stent surface and prevents smooth muscle cell growth reducing hyperplasia and thrombosis in in vivo models.

Nitric oxide-releasing poly(ε-caprolactone)/S-nitrosylated keratin biocomposite scaffolds for potential small-diameter vascular grafts

Rapid endothelialization and regulation of smooth muscle cell proliferation are crucial for small-diameter vascular grafts to address poor compliance, thromboembolism, and intimal hyperplasia, and achieve revascularization. As a gaseous signaling molecule, nitric oxide (NO) regulates cardiovascular homeostasis, inhibits blood clotting and intimal hyperplasia, and promotes the growth of endothelial cells. Due to the instability and burst release of small molecular NO donors, a novel biomacromolecular donor has generated increasing interest. In the study, a low toxic NO donor of S-nitrosated keratin (KSNO) was first synthesized and then coelectrospun with poly(ε-caprolactone) to afford NO-releasing small-diameter vascular graft. PCL/KSNO graft was capable to generate NO under the catalysis of ascorbic acid (Asc), so the graft selectively elevated adhesion and growth of human umbilical vein endothelial cells (HUVECs), while inhibited the proliferation of human aortic smooth muscle cells (HASMCs) in the presence of Asc. In addition, the graft displayed significant antibacterial properties and good blood compatibility. Animal experiments showed that the biocomposite graft could inhibit thrombus formation and preserve normal blood flow via single rabbit carotid artery replacement for 1 month. More importantly, a complete endothelium was observed on the lumen surface. Taken together, PCL/KSNO small-diameter vascular graft has potential applications in vascular tissue engineering with rapid endothelialization and vascular remolding.

Controlling Reperfusion Injury With Controlled Reperfusion: Historical Perspectives and New Paradigms

Cardiac reperfusion injury is a well-established outcome following treatment of acute myocardial infarction and other types of ischemic heart conditions. Numerous cardioprotection protocols and therapies have been pursued with success in pre-clinical models. Unfortunately, there has been lack of successful large-scale clinical translation, perhaps in part due to the multiple pathways that reperfusion can contribute to cell death. The search continues for new cardioprotection protocols based on what has been learned from past results. One class of cardioprotection protocols that remain under active investigation is that of controlled reperfusion. This class consists of those approaches that modify, in a controlled manner, the content of the reperfusate or the mechanical properties of the reperfusate (e.g., pressure and flow). This review article first provides a basic overview of the primary pathways to cell death that have the potential to be addressed by various forms of controlled reperfusion, including no-reflow phenomenon, ion imbalances (particularly calcium overload), and oxidative stress. Descriptions of various controlled reperfusion approaches are described, along with summaries of both mechanistic and outcome-oriented studies at the pre-clinical and clinical phases. This review will constrain itself to approaches that modify endogenously-occurring blood components. These approaches include ischemic postconditioning, gentle reperfusion, controlled hypoxic reperfusion, controlled hyperoxic reperfusion, controlled acidotic reperfusion, and controlled ionic reperfusion. This review concludes with a discussion of the limitations of past approaches and how they point to potential directions of investigation for the future.

Psychological/mental stress-induced effects on urinary function: Possible brain molecules related to psychological/mental stress-induced effects on urinary function

Exposure to psychological/mental stress can affect urinary function, and lead to and exacerbate lower urinary tract dysfunctions. There is increasing evidence showing stress-induced changes not only at phenomenological levels in micturition, but also at multiple levels, lower urinary tract tissues, and peripheral and central nervous systems. The brain plays crucial roles in the regulation of the body's responses to stress; however, it is still unclear how the brain integrates stress-related information to induce changes at these multiple levels, thereby affecting urinary function and lower urinary tract dysfunctions. In this review, we introduce recent urological studies investigating the effects of stress exposure on urinary function and lower urinary tract dysfunctions, and our recent studies exploring "pro-micturition" and "anti-micturition" brain molecules related to stress responses. Based on evidence from these studies, we discuss the future directions of central neurourological research investigating how stress exposure-induced changes at peripheral and central levels affect urinary function and lower urinary tract dysfunctions. Brain molecules that we explored might be entry points into dissecting the stress-mediated process for modulating micturition.

The mitochondrial thioredoxin reductase system (TrxR2) in vascular endothelium controls peroxynitrite levels and tissue integrity

The mitochondrial thioredoxin/peroxiredoxin system encompasses NADPH, thioredoxin reductase 2 (TrxR2), thioredoxin 2, and peroxiredoxins 3 and 5 (Prx3 and Prx5) and is crucial to regulate cell redox homeostasis via the efficient catabolism of peroxides (TrxR2 and Trxrd2 refer to the mitochondrial thioredoxin reductase protein and gene, respectively). Here, we report that endothelial TrxR2 controls both the steady-state concentration of peroxynitrite, the product of the reaction of superoxide radical and nitric oxide, and the integrity of the vascular system. Mice with endothelial deletion of the Trxrd2 gene develop increased vascular stiffness and hypertrophy of the vascular wall. Furthermore, they suffer from renal abnormalities, including thickening of the Bowman's capsule, glomerulosclerosis, and functional alterations. Mechanistically, we show that loss of Trxrd2 results in enhanced peroxynitrite steady-state levels in both vascular endothelial cells and vessels by using a highly sensitive redox probe, fluorescein-boronate. High steady-state peroxynitrite levels were further found to coincide with elevated protein tyrosine nitration in renal tissue and a substantial change of the redox state of Prx3 toward the oxidized protein, even though glutaredoxin 2 (Grx2) expression increased in parallel. Additional studies using a mitochondria-specific fluorescence probe (MitoPY1) in vessels revealed that enhanced peroxynitrite levels are indeed generated in mitochondria. Treatment with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin [Mn(III)TMPyP], a peroxynitrite-decomposition catalyst, blunted intravascular formation of peroxynitrite. Our data provide compelling evidence for a yet-unrecognized role of TrxR2 in balancing the nitric oxide/peroxynitrite ratio in endothelial cells in vivo and thus establish a link between enhanced mitochondrial peroxynitrite and disruption of vascular integrity.

Inflammatory and Biomechanical Drivers of Endothelial-Interstitial Interactions in Calcific Aortic Valve Disease

Calcific aortic valve disease is dramatically increasing in global burden, yet no therapy exists outside of prosthetic replacement. The increasing proportion of younger and more active patients mandates alternative therapies. Studies suggest a window of opportunity for biologically based diagnostics and therapeutics to alleviate or delay calcific aortic valve disease progression. Advancement, however, has been hampered by limited understanding of the complex mechanisms driving calcific aortic valve disease initiation and progression towards clinically relevant interventions.

Tribulus terrestris L. Extract Protects against Lipopolysaccharide-Induced Inflammation in RAW 264.7 Macrophage and Zebrafish via Inhibition of Akt/MAPKs and NF-κB/iNOS-NO Signaling Pathways

Inflammation response is a regulated cellular process and excessive inflammation has been recognized in numerous diseases, such as cardiovascular disease, neurodegenerative disease, inflammatory bowel disease, and cancer. Tribulus terrestris L. (TT), also known as Bai Jili in Chinese, has been applied in traditional Chinese medicine for thousands of years while its anti-inflammatory activity and underlying mechanism are not fully elucidated. Here, we hypothesize Tribulus terrestris L. extract (BJL) which presents anti-inflammatory effect, and the action mechanism was also investigated. We employed the transgenic zebrafish line Tg(MPO:GFP), which expresses green fluorescence protein (GFP) in neutrophils, and mice macrophage RAW 264.7 cells as the in vivo and in vitro model to evaluate the anti-inflammatory effect of BJL, respectively. The production of nitric oxide (NO) was measured by Griess reagent. The mRNA expression levels of inflammatory cytokines and inducible nitric oxide synthase (iNOS) were measured by real-time PCR, and the intracellular total or phosphorylated protein levels of NF-κB, Akt, and MAPKs including MEK, ERK, p38, and JNK were detected by western blot. We found that BJL significantly inhibited fin transection or lipopolysaccharide- (LPS-) induced neutrophil migration and aggregation in zebrafish in vivo. In mice macrophage RAW 264.7 cells, BJL ameliorated LPS-triggered excessive release of NO and transcription of inflammatory cytokine genes including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). BJL also reduced the LPS-induced elevations of intracellular iNOS and nuclear factor kappa B (NF-κB) which mediate the cellular NO and inflammatory cytokine productions, respectively. Moreover, LPS dramatically increased the phosphorylation of Akt and MAPKs including MEK, ERK, p38, and JNK in RAW 264.7 cells, while cotreatment BJL with LPS suppressed their phosphorylation. Taken together, our data suggested that BJL presented potent anti-inflammatory effect and the underlying mechanism was closely related to the inhibition of Akt/MAPKs and NF-κB/iNOS-NO signaling pathways.

Effects of Exogenous Androgens on Platelet Activity and Their Thrombogenic Potential in Supraphysiological Administration: A Literature Review

Anabolic androgenic steroids (AAS), simply called “androgens”, represent the most widespread drugs used to enhance performance and appearance in a sporting environment. High-dosage and/or long-term AAS administration has been associated frequently with significant alterations in the cardiovascular system, some of these with severe endpoints. The induction of a prothrombotic state is probably the most life-threatening consequence, suggested by numerous case reports in AAS-abusing athletes, and by a considerable number of human and animal studies assessing the influence of exogenous androgens on hemostasis. Despite over fifty years of research, data regarding the thrombogenic potential of exogenous androgens are still scarce. The main reason is the limited possibility of conducting human prospective studies. However, human observational studies conducted in athletes or patients, in vitro human studies, and animal experiments have pointed out that androgens in supraphysiological doses induce enhanced platelet activity and thrombopoiesis, leading to increased platelet aggregation. If this tendency overlaps previously existing coagulation and/or fibrinolysis dysfunctions, it may lead to a thrombotic diathesis, which could explain the multitude of thromboembolic events reported in the AAS-abusing population. The influence of androgen excess on the platelet activity and fluid–coagulant balance remains a subject of debate, urging for supplementary studies in order to clarify the effects on hemostasis, and to provide new compelling evidence for their claimed thrombogenic potential.

Local and Systemic Alterations of the L-Arginine/Nitric Oxide Pathway in Sputum, Blood, and Urine of Pediatric Cystic Fibrosis Patients and Effects of Antibiotic Treatment

Alterations in the L-arginine (Arg)/nitric oxide (NO) pathway have been reported in cystic fibrosis (CF; OMIM 219700) as the result of various factors including systemic and local inflammatory activity in the airways. The aim of the present study was to evaluate the Arg/NO metabolism in pediatric CF patients with special emphasis on lung impairment and antibiotic treatment. Seventy CF patients and 78 healthy controls were included in the study. CF patients (43% male, median age 11.8 years) showed moderately impaired lung functions (FEV1 90.5 ± 19.1% (mean ± SD); 21 (30%) had a chronic Pseudomonas aeruginosa (PSA) infection, and 24 (33%) had an acute exacerbation). Plasma, urinary, and sputum concentrations of the main Arg/NO metabolites, nitrate, nitrite, Arg, homoarginine (hArg), and asymmetric dimethylarginine (ADMA) were determined in pediatric CF patients and in healthy age-matched controls. Clinical parameters in CF patients included lung function and infection with PSA. Additionally, the Arg/NO pathway in sputum samples of five CF patients was analyzed before and after routine antibiotic therapy. CF patients with low fractionally exhaled NO (FENO) showed lower plasma Arg and nitrate concentrations. During acute exacerbation, sputum Arg and hArg levels were high and dropped after antibiotic treatment: Arg: pre-antibiotics: 4.14 nmol/25 mg sputum vs. post-antibiotics: 2.33 nmol/25 mg sputum, p = 0.008; hArg: pre-antibiotics: 0.042 nmol/25 mg sputum vs. post-antibiotics: 0.029 nmol/25 mg sputum, p = 0.035. The activated Arg/NO metabolism in stable CF patients may be a result of chronic inflammation. PSA infection did not play a major role regarding these differences. Exacerbation increased and antibiotic therapy decreased sputum Arg concentrations.

Gold Nanorod-Based Nanoplatform Catalyzes Constant NO Generation and Protects from Cardiovascular Injury

Cardiovascular disease is a leading cause of death, and one of the effective therapeutic strategies for cardiovascular disease is to provide a controlled, constant supply of nitric oxide (NO) in a mild manner; however, this has proved challenging in the clinic. To address this problem, we built a nitric oxide synthase (NOS)-like nanoplatform (NanoNOS) that consists of a noble metal nanoparticle core and a mesoporous silica shell and demonstrated the ability of NanoNOS to catalyze production of NO in vitro. Mechanistic studies show that the catalysis consists of a three-step reaction: the oxidation of NADPH to produce O₂^-via oxidase-like activity and the subsequent dismutation of O₂^- to H₂O₂via SOD-like activity, followed by H₂O₂-mediated oxidation of l-arginine to produce NO via a nonenzymatic pathway. The generation of NO is precisely regulated by both the content of the NanoNOS species and the plasmon excitation. We found that NanoNOS greatly suppressed injury-driven monocyte-endothelial cell adhesion, suggesting the NanoNOS treatment could help prevent cardiovascular disease. With such a design as well as plasmon excitation that allows for controlled and constant catalytic activity, NanoNOS technology could have a variety of biomedical applications.

Atherosclerosis Linked to Aberrant Amino Acid Metabolism and Immunosuppressive Amino Acid Catabolizing Enzymes

Cardiovascular disease is the leading global health concern and responsible for more deaths worldwide than any other type of disorder. Atherosclerosis is a chronic inflammatory disease in the arterial wall, which underpins several types of cardiovascular disease. It has emerged that a strong relationship exists between alterations in amino acid (AA) metabolism and the development of atherosclerosis. Recent studies have reported positive correlations between levels of branched-chain amino acids (BCAAs) such as leucine, valine, and isoleucine in plasma and the occurrence of metabolic disturbances. Elevated serum levels of BCAAs indicate a high cardiometabolic risk. Thus, BCAAs may also impact atherosclerosis prevention and offer a novel therapeutic strategy for specific individuals at risk of coronary events. The metabolism of AAs, such as L-arginine, homoarginine, and L-tryptophan, is recognized as a critical regulator of vascular homeostasis. Dietary intake of homoarginine, taurine, and glycine can improve atherosclerosis by endothelium remodeling. Available data also suggest that the regulation of AA metabolism by indoleamine 2,3-dioxygenase (IDO) and arginases 1 and 2 are mediated through various immunological signals and that immunosuppressive AA metabolizing enzymes are promising therapeutic targets against atherosclerosis. Further clinical studies and basic studies that make use of animal models are required. Here we review recent data examining links between AA metabolism and the development of atherosclerosis.

Impact of Lifestyles (Diet and Exercise) on Vascular Health: Oxidative Stress and Endothelial Function

Healthy lifestyle and diet are associated with significant reduction in risk of obesity, type 2 diabetes, and cardiovascular diseases. Oxidative stress and the imbalance between prooxidants and antioxidants are linked to cardiovascular and metabolic diseases. Changes in antioxidant capacity of the body may lead to oxidative stress and vascular dysfunction. Diet is an important source of antioxidants, while exercise offers many health benefits as well. Recent findings have evidenced that diet and physical factors are correlated to oxidative stress. Diet and physical factors have debatable roles in modulating oxidative stress and effects on the endothelium. Since endothelium and oxidative stress play critical roles in cardiovascular and metabolic diseases, dietary and physical factors could have significant implications on prevention of the diseases. This review is aimed at summarizing the current knowledge on the impact of diet manipulation and physical factors on endothelium and oxidative stress, focusing on cardiovascular and metabolic diseases. We discuss the friend-and-foe role of dietary modification (including different diet styles, calorie restriction, and nutrient supplementation) on endothelium and oxidative stress, as well as the potential benefits and concerns of physical activity and exercise on endothelium and oxidative stress. A fine balance between oxidative stress and antioxidants is important for normal functions in the cells and interfering with this balance may lead to unfavorable effects. Further studies are needed to identify the best diet composition and exercise intensity.

Endothelial Dysfunction in Chronic Kidney Disease, from Biology to Clinical Outcomes: A 2020 Update

The vascular endothelium is a dynamic, functionally complex organ, modulating multiple biological processes, including vascular tone and permeability, inflammatory responses, thrombosis, and angiogenesis. Endothelial dysfunction is a threat to the integrity of the vascular system, and it is pivotal in the pathogenesis of atherosclerosis and cardiovascular disease. Reduced nitric oxide (NO) bioavailability is a hallmark of chronic kidney disease (CKD), with this disturbance being almost universal in patients who reach the most advanced phase of CKD, end-stage kidney disease (ESKD). Low NO bioavailability in CKD depends on several mechanisms affecting the expression and the activity of endothelial NO synthase (eNOS). Accumulation of endogenous inhibitors of eNOS, inflammation and oxidative stress, advanced glycosylation products (AGEs), bone mineral balance disorders encompassing hyperphosphatemia, high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23), and low levels of the active form of vitamin D (1,25 vitamin D) and the anti-ageing vasculoprotective factor Klotho all impinge upon NO bioavailability and are critical to endothelial dysfunction in CKD. Wide-ranging multivariate interventions are needed to counter endothelial dysfunction in CKD, an alteration triggering arterial disease and cardiovascular complications in this high-risk population.

Activated L-Arginine/Nitric Oxide Pathway in Pediatric Cystic Fibrosis and Its Association with Pancreatic Insufficiency, Liver Involvement and Nourishment: An Overview and New Results

Cystic fibrosis (CF; OMIM 219700) is a rare genetic disorder caused by a chloride channel defect, resulting in lung disease, pancreas insufficiency and liver impairment. Altered L-arginine (Arg)/nitric oxide (NO) metabolism has been observed in CF patients’ lungs and in connection with malnutrition. The aim of the present study was to investigate markers of the Arg/NO pathway in the plasma and urine of CF patients and to identify possible risk factors, especially associated with malnutrition. We measured the major NO metabolites nitrite and nitrate, Arg, a semi-essential amino acid and NO precursor, the NO synthesis inhibitor asymmetric dimethylarginine (ADMA) and its major urinary metabolite dimethylamine (DMA) in plasma and urine samples of 70 pediatric CF patients and 78 age-matched healthy controls. Biomarkers were determined by gas chromatography–mass spectrometry and high-performance liquid chromatography. We observed higher plasma Arg (90.3 vs. 75.6 µM, p < 0.0001), ADMA (0.62 vs. 0.57 µM, p = 0.03), Arg/ADMA ratio (148 vs. 135, p = 0.01), nitrite (2.07 vs. 1.95 µM, p = 0.03) and nitrate (43.3 vs. 33.1 µM, p < 0.001) concentrations, as well as higher urinary DMA (57.9 vs. 40.7 µM/mM creatinine, p < 0.001) and nitrate (159 vs. 115 µM/mM creatinine, p = 0.001) excretion rates in the CF patients compared to healthy controls. CF patients with pancreatic sufficiency showed plasma concentrations of the biomarkers comparable to those of healthy controls. Malnourished CF patients had lower Arg/ADMA ratios (p = 0.02), indicating a higher NO synthesis capacity in sufficiently nourished CF patients. We conclude that NO production, protein-arginine dimethylation, and ADMA metabolism is increased in pediatric CF patients. Pancreas and liver function influence Arg/NO metabolism. Good nutritional status is associated with higher NO synthesis capacity and lower protein-arginine dimethylation.

Beyond the myocardium? SGLT2 inhibitors target peripheral components of reduced oxygen flux in the diabetic patient with heart failure with preserved ejection fraction

Recent cardiovascular outcome trials have highlighted the propensity of the antidiabetic agents, SGLT2 inhibitors (SGLT2is or -flozin drugs), to exert positive clinical outcomes in patients with cardiovascular disease at risk for major adverse cardiovascular events (MACEs). Of interest in cardiac diabetology is the physiological status of the patient with T2DM and heart failure with preserved ejection fraction (HFpEF), a well-examined association. Underlying this pathologic tandem are the effects that long-standing hyperglycemia has on the ability of the HFpEF heart to adequately deliver oxygen. It is believed that shortcomings in oxygen diffusion or utilization and the resulting hypoxia thereafter may play a role in underlying the clinical sequelae of patients with T2DM and HFpEF, with implications in the long-term decline of extra-cardiac tissue. Oxygen consumption is one of the most critical factors in indexing heart failure disease burden, warranting a probe into the role of SGLT2i on oxygen utility in HFpEF and T2DM. We investigated the role of oxygen flux in the patient with T2DM and HFpEF extending beyond the heart with focuses on cellular metabolism, perivascular fibrosis with endothelial dysfunction, hematologic changes, and renal effects with neurohormonal considerations in the patient with HFpEF and T2DM. Moreover, we give a commentary on potential therapeutic targets of these components with SGLT2i to gain insight into disease burden amelioration in patients with HFpEF and T2DM.

Exosome Derived from Coronary Serum of Patients with Myocardial Infarction Promotes Angiogenesis Through the miRNA-143/IGF-IR Pathway

Purpose

Myocardial ischemia-reperfusion injury primarily causes myocardial infarction (MI), which is manifested by cell death. Angiogenesis is essential for repair and regeneration in cardiac tissue after MI. In this study, we aimed to investigate the effect of exosomes derived from the serum of MI patients in angiogenesis and its related mechanism.

Patients and Methods

Exosomes, isolated from serum, were collected from MI (MI-exosome) and control (Con-exosome) patients. After coculturing with human umbilical vein endothelial cells, MI-exosome promoted cell proliferation, migration, and tube formation.

Results

The results revealed that the production and release of MI-exosome were associated with cardiomyocytes. Moreover, microarray assays demonstrated that miRNA-143 was significantly decreased in MI-exosome. Meanwhile, the overexpression and knockdown of miRNA-143 could inhibit and enhance angiogenesis, respectively. Furthermore, the effect of exosomal miRNA-143 on angiogenesis was mediated by its targeting gene, insulin-like growth factor 1 receptor (IGF-IR), and was associated with the production of nitric oxide (NO).

Conclusion

Taken together, exosomes derived from the serum of patients with MI promoted angiogenesis through the IGF-IR/NO signaling pathway. The results provide novel understanding of the function of exosomes in MI.

Polyphenols Regulate Endothelial Functions and Reduce the Risk of Cardiovascular Disease

BACKGROUND

Previous studies have shown that intake of polyphenols through the consumption of vegetables and fruits reduces the risk of Cardiovascular Disease (CVD) by potentially influencing endothelial cell function.

OBJECTIVE

In this review, the effects and molecular mechanisms of plant polyphenols, particularly resveratrol, epigallocatechin gallate (EGCG), and quercetin, on endothelial functions, and their putative protective effects against CVD are described.

METHODS

Epidemiologic studies examined the effect of the CVD risk of vegetables and the fruit. Furthermore, studies within vitro models investigated the underlying molecular mechanisms of the action of the flavonoid class of polyphenols. These findings help elucidate the effect of polyphenols on endothelial function and CVD risk reduction.

RESULTS

Epidemiologic and in vitro studies have demonstrated that the consumption of vegetables and fruits decreases the incidence of CVDs. Furthermore, it has also been indicated that dietary polyphenols are inversely related to the risk of CVD. Resveratrol, EGCG, and quercetin prevent oxidative stress by regulating the expression of oxidase and the antioxidant enzyme genes, contributing to the prevention of stroke, hypertension, heart failure, and ischemic heart disease.

CONCLUSION

High intake of dietary polyphenols may help prevent CVD. Polyphenols inhibit endothelial dysfunction and induce vascular endothelium-dependent vascular relaxation viz. redox regulation and nitric oxide production. The polyphenol-induced healthy endothelial cell function may be related to CVD prevention.

Upregulation of Connexin 40 Mediated by Nitric Oxide Attenuates Cerebral Vasospasm After Subarachnoid Hemorrhage via the Nitric Oxide-Cyclic Guanosine Monophosphate-Protein Kinase G Pathway

OBJECTIVE

The present study was performed to elucidate the role of nitric oxide (NO) and connexin 40 (Cx40) in the induction of cerebral vasospasm after subarachnoid hemorrhage (SAH) in vivo.

METHODS

A SAH rat model was established using the double-bleed method. A total of 108 Sprague-Dawley rats weighing 250-300 g were randomly divided into 6 groups: SAH; SAH plus diethylenetriamine (DETA)/NO (exogenous NO donor); SAH plus 8-bromoadenosine (8-Br)-cyclic guanosine monophosphate (cGMP; protein kinase G [PKG] activator); SAH plus DETA/NO plus KT5823 (PKG inhibitor); SAH plus DETA/NO plus 40Gap27 (Cx40 inhibitor); and sham. The changes in the diameter of the branch microvessels in the middle cerebral artery were recorded. The neurological score was evaluated using the Garcia scoring system. Basilar artery (BA) tension was measured using the Danish Myo Technology myograph system. Cx40 protein expression was analyzed using immunofluorescence and Western blotting. Endothelial NO synthase, soluble guanylate cyclase, and PKG protein expression were measured by Western blotting.

RESULTS

A considerable narrowing of the cerebral vessels was detected in the SAH group compared with that in the sham group. Moreover, compared with the sham group, the SAH group showed a marked decrease in Cx40, endothelial NO synthase, soluble guanylate cyclase, and PKG expression. The expression of Cx40 and PKG were obviously higher in the SAH plus DETA/NO and SAH plus 8-Br-cGMP groups than in the SAH group. However, Cx40 was lower in the SAH plus DETA/NO plus KT5823 and SAH plus DETA/NO plus 40Gap27 groups than in the SAH plus ETA/NO group. The BAs showed significant vasodilation in the SAH plus DETA/NO and SAH plus 8-Br-cGMP groups. However, the vasodilation response of BAs was inhibited in the SAH plus DETA/NO plus KT5823 and SAH plus DETA-NO plus 40Gap27 groups.

CONCLUSIONS

The NO-cGMP-PKG pathway alleviated cerebral vasospasm via Cx40 upregulation.

Hypergravity Activates a Pro-Angiogenic Homeostatic Response by Human Capillary Endothelial Cells

Capillary endothelial cells are responsible for homeostatic responses to organismic and environmental stimulations. When malfunctioning, they may cause disease. Exposure to microgravity is known to have negative effects on astronauts’ physiology, the endothelium being a particularly sensitive organ. Microgravity-related dysfunctions are striking similar to the consequences of sedentary life, bed rest, and ageing on Earth. Among different countermeasures implemented to minimize the effects of microgravity, a promising one is artificial gravity. We examined the effects of hypergravity on human microvascular endothelial cells of dermal capillary origin (HMEC-1) treated at 4 g for 15 min, and at 20 g for 15 min, 3 and 6 h. We evaluated cell morphology, gene expression and 2D motility and function. We found a profound rearrangement of the cytoskeleton network, dose-dependent increase of Focal Adhesion kinase (FAK) phosphorylation and Yes-associated protein 1 (YAP1) expression, suggesting cell stiffening and increased proneness to motility. Transcriptome analysis showed expression changes of genes associated with cardiovascular homeostasis, nitric oxide production, angiogenesis, and inflammation. Hypergravity-treated cells also showed significantly improved motility and function (2D migration and tube formation). These results, expanding our knowledge about the homeostatic response of capillary endothelial cells, show that adaptation to hypergravity has opposite effect compared to microgravity on the same cell type.

Control of tumor angiogenesis and metastasis through modulation of cell redox state

Redox reactions pervade all biology. The control of cellular redox state is essential for bioenergetics and for the proper functioning of many biological functions. This review traces a timeline of findings regarding the connections between redox and cancer. There is ample evidence of the involvement of cellular redox state on the different hallmarks of cancer. Evidence of the control of tumor angiogenesis and metastasis through modulation of cell redox state is reviewed and highlighted.

Enhanced Nitric Oxide (NO) and Decreased ADMA Synthesis in Pediatric ADHD and Selective Potentiation of NO Synthesis by Methylphenidate

Attention deficit hyperactivity disorder (ADHD) is a common pediatric psychiatric disorder, frequently treated with methylphenidate (MPH). Recently, MPH’s cardiovascular safety has been questioned by observational studies describing an increased cardiovascular risk in adults and blood pressure alterations in children. We considered members of the L-arginine (Arg)/nitric oxide (NO) pathway as possible early cardiovascular risk factors in pediatric ADHD children. They include the NO metabolites, nitrite and nitrate, the NO precursor Arg, and asymmetric dimethylarginine (ADMA), an endogenous NO synthase (NOS) inhibitor and a cardiovascular risk factor in adults. We conducted a prospective clinical trial with 42 ADHD children (aged 6–16 years) with (n = 19) and without (n = 23) MPH treatment. Age-matched children without ADHD (n = 43) served as controls. All plasma and urine metabolites were determined by gas chromatography-mass spectrometry. We observed higher plasma nitrite and lower plasma ADMA concentrations in the ADHD children. MPH-treated ADHD children had higher plasma nitrite concentrations than MPH-untreated ADHD children. As NOS activity is basally inhibited by ADMA, MPH treatment seems to have decreased the inhibitory potency of ADMA. Percentiles of systolic blood pressure were higher in MPH-treated ADHD children. The underlying mechanisms and their implications in the MPH therapy of pediatric ADHD with MPH remain to be elucidated in larger cohorts.

Nitric-Oxide-Releasing Biomaterial Regulation of the Stem Cell Microenvironment in Regenerative Medicine

Stem cell therapy has proven to be an attractive solution for the treatment of degenerative diseases or injury. However, poor cell engraftment and survival within injured tissues limits the successful use of stem cell therapy within the clinical setting. Nitric oxide (NO) is an important signaling molecule involved in various physiological processes. Emerging evidence supports NO's diverse roles in modulating stem cell behavior, including survival, migration, differentiation, and paracrine secretion of proregenerative factors. Thus, there has been a shift in research focus to concentrate efforts on the delivery of therapeutic concentration ranges of NO to the target tissue sites. Combinatory therapies utilizing biomaterials that control NO generation and support stem cell delivery can be holistic and synergistic approaches to significantly improve tissue regeneration. Here, the focus is on recent developments of various therapeutic platforms, engineered to both transport NO and to enhance stem-cell-mediated regeneration of damaged tissues. New and emerging revelations of how the stem cell microenvironment can be regulated by NO-releasing biomaterials are also highlighted.

Design of a FRET-based fluorescent probe for the reversible detection of SO2and formaldehyde in living cells and mice

Design of a FRET-based fluorescent probe for the reversible detection of SO₂and formaldehyde in living cells and mice.