Penile erection and cardiovascular function: effects and pathophysiology.

Penile erection (PE) is a hemodynamic event that results from a neuroendocrine process, and it is influenced by the cardiovascular status of the patient. However, it may also modulate an individual's cardiovascular events. The present study provides the mechanisms involved in the association of PE and cardiovascular function. Erection upsurges the cardiac rate, blood pressure, and oxygen uptake. Sex-enhancing strategies, such as phosphodiesterase inhibitors, alprostadil, and testosterone also promote vasodilatation and cardiac performance, thus preventing myocardial infarction. More so, drugs that are used in the treatment of hypertensive heart diseases (such as angiotensin system inhibitors and ß-blockers) facilitate vasodilatation and PE. These associations have been linked with nitric oxide- and testosterone-dependent enhancing effects on the vascular endothelium. In addition, impaired cardiovascular function may negatively impact PE; therefore, impaired PE may be a pointer to cardiovascular pathology. Hence, evaluation of the cardiovascular status of an individual with erectile dysfunction (ED) is essential. Also, employing strategies that are used in maintaining optimal cardiac function may be useful in the management of ED.

[Diagnosis and therapy of patients with asthma in Germany. Results of the care study RELEVANT]. / Diagnostik und Therapie von Patienten mit Asthma in Deutschland : Ergebnisse der Versorgungsstudie RELEVANT.

BACKGROUND: Diagnostic and therapeutic options for asthma have improved with asthma control and remission being of central importance. The RELEVANT study aimed for a nationwide snapshot of current asthma diagnosis and treatment in general practice and specialty care for identification of further aspects for optimization. METHOD: RELEVANT is a nationwide cross-sectional study using a structured questionnaire. This comprised 14 questions on asthma-related topics covering diagnostics and therapy. Participants were general practitioners/internal medicine specialists and pulmonologists. RESULTS: A total of 1,558 persons took part in the survey. Regarding relevant specific diagnostic procedures for asthma, GPs/internists almost exclusively mentioned pulse oximetry. Among the pulmonologists, fractional exhaled nitric oxide (FeNO) measurement was mentioned, among others. FeNO and blood eosinophils were only mentioned by the pulmonologists as diagnostic and treatment-relevant markers. A total of more than 60% of the GPs/internists surveyed stated that only around 25% or fewer of their patients would voluntarily report restrictions in their everyday lives. Regarding drug treatment, the majority stated that they recognized differences between various ICS/LABA combination therapies. CONCLUSIONS: The results indicate a need for optimization, particularly regarding asthma control. This involves both a better assessment by patients' everyday life restrictions and modern ways of assessing asthma control in cooperation between GPs/internal medicine specialists and pulmonologists. One fifth of respondents do not see any differences between various ICS/LABA combinations in daily practice, although there are pharmacodynamic and pharmacokinetic differences.

Immunological studies on the effects of toltrazuril and neem extract in broiler chickens suffering from coccidiosis.

Background: The prevalence of avian coccidiosis in the poultry industry has grown, resulting in substantial financial losses from high mortality, stunted growth, reduced productivity, and expensive medical expenses. Aim: The purpose of the current study was to assess the immunological effects of neem leaf extract and toltrazuril on broilers that had contracted coccidiosis. Methods: In this investigation, 100 one-day-old Cobb broiler chicks without sexes were employed. The chicks were divided into five equal groups, with 20 birds in each. On the 14th day of life, the birds in groups 2, 3, 4, and 5 received an oral inoculation with 1 × 105 sporulated oocysts of Eimeria tenella (E. tenella) (field isolate). The first group (Gp), which consists of 20 healthy broilers, served as a negative control. Gp (2) contains experimentally infected broilers and nontreated (served as a positive control). Gp (3) contains experimentally infected broilers treated with toltrazuril (1 ml/l drinking water) for two consecutive days. Gp (4) contains experimentally infected broilers treated with neem leaf extract 4% (50 ml/l drinking water) for 5 successive days, and Gp (5) contains experimentally infected broilers treated with toltrazuril (1 ml/l drinking water) and a half dose of neem leaves extract 4% (25 ml/l drinking water) for 5 successive days. For the purpose of estimating body weight growth and feed conversion ratio, each broiler was weighed separately at the start of the trial and again on the 1st and 10th day after treatment. In addition to obtaining intestinal samples for immunohistochemistry, blood samples were also obtained for immunological examination. Results: As compared to the negative control group, the experimentally infested broilers with E. tenella showed significant decreases in serum nitric oxide, lysosome, phagocytic percent, and phagocytic index, along with significant increases in white blood cells (WBCs), lymphocyte, heterophilis, eosinophilis, basophilis, monocyte, serum total protein, γ globulin, fibrinogen, and haptoglobin. When compared to the control positive group, experimentally infested broilers treated with either neem or toltrazuril alone or in combination demonstrated significant increases in serum total protein, nitric oxide, lysozyme, phagocytic percent, and phagocytic index, but significant decreases in WBCs, lymphocytes, heterophile, eosinophile, basophile, and monocyte. The intestinal peroxidase stain of broilers infected with E. tenella exhibited a significant positive expression for CD4, but the infected broilers treated with toltrazuril and half a dosage of neem displayed a negative expression for CD4, identical to the negative control. Conclusion: The broiler chickens infested with E. tenella may have a variety of negative impacts on their immune systems and immunohistopathological findings. Nonetheless, toltrazuril and neem extract, either separately or in combination, function as anticoccidial medications that may enhance the broiler chicks' immune state.

Platelet rich plasma alleviates endometritis induced by lipopolysaccharide in mice via inhibiting TLR4/NF-κB signaling pathway.

BACKGROUND: Endometritis is an inflammatory reaction of the lining of uterus, leading to the occurrence of infertility. Platelet rich plasma (PRP) has been proven to exhibit extremely effective for the treatment of endometrium-associated infertility, but the mechanism of its prevention for endometritis remains unclear. OBJECTIVE: The present study aimed to investigate the protective effect of PRP against endometritis induced by lipopolysaccharide (LPS) and elucidate the mechanism underlying these effects. METHODS: Mouse model of endometritis was established by intrauterine perfusion of LPS. PRP intrauterine infusion was administered at 24 h after LPS induction. After another 24 h, the uterine tissues were harvested to observe histopathological changes, production of proinflammatory cytokines, variation of the Toll-like receptor 4/nuclear factor κB (TLR4/NF-κB) signaling pathways, and validated the anti-inflammatory effect of PRP. The myeloperoxidase (MPO) activity and concentration of nitric oxide (NO) were determined using assay kit. Proinflammatory chemokines (tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6)) were measured by ELISA and Real-Time PCR. The activity of TLR4/NF-κB pathway in uterine tissues was measured by Western blotting. RESULTS: Hematoxylin-eosin staining (H&E) appeared that PRP remarkably relieved the impairment of uterine tissues. Detection of MPO activity and concentration of NO revealed that PRP treatment distinctly mitigated infiltration of inflammatory cells in mice with endometritis induced by LPS. PRP treatment significantly affected the expression of TNF-α, IL-1ß, and IL-6. PRP was also found to suppress LPS-induced activation of TLR4/NF-κB pathway. CONCLUSION: PRP effectively alleviates LPS-induced endometritis via restraining the signal pathway of TLR4/NF-κB. These findings provide a solid foundation for PRP as a potential therapeutic agent for endometritis.

Inhaled Nitric Oxide ReDuce postoperatIve pulmoNAry complicaTions in patiEnts with recent COVID-19 infection (INORDINATE): protocol for a randomised controlled trial.

BACKGROUND: A history of SARS-CoV-2 infection has been reported to be associated with an increased risk of postoperative pulmonary complications (PPCs). Even mild PPCs can elevate the rates of early postoperative mortality, intensive care unit (ICU) admission and prolong the length of ICU and/or hospital stays. Consequently, it is crucial to develop perioperative management strategies that can mitigate these increased risks in surgical patients who have recently been infected with SARS-CoV-2. Accumulating evidence suggests that nitric oxide (NO) inhalation might be effective in treating COVID-19. NO functions in COVID-19 by promoting vasodilation, anticoagulation, anti-inflammatory and antiviral effects. Therefore, our study hypothesises that the perioperative use of NO can effectively reduce PPCs in patients with recent SARS-CoV-2 infection. METHOD AND ANALYSIS: A prospective, double-blind, single-centre, randomised controlled trial is proposed. The trial aims to include participants who are planning to undergo surgery with general anaesthesia and have been recently infected with SARS-CoV-2 (within 7 weeks). Stratified allocation of eligible patients will be performed at a 1:1 ratio based on the predicted risk of PPCs using the Assess Respiratory Risk in Surgical Patients in Catalonia risk index and the time interval between infection and surgery.The primary outcome of the study will be the presence of PPCs within the first 7 days following surgery, including respiratory infection, respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm and aspiration pneumonitis. The primary outcome will be reported as counts (percentage) and will be compared using a two-proportion χ2 test. The common effect across all primary components will be estimated using a multiple generalised linear model. ETHICS AND DISSEMINATION: The trial is approved by the Institutional Review Board of Xijing Hospital (KY20232058-F1). The findings, including positive, negative and inconclusive results, will be published in scientific journals with peer-review processes. TRIAL REGISTRATION NUMBER: NCT05721144.

Targeted Therapies for Neonatal Pulmonary Hypertension: Beyond Nitric Oxide.

Pulmonary hypertension in the neonatal population can be acute or chronic and carries significant risk for morbidity and mortality. It can be idiopathic but more often is associated with comorbid pulmonary and heart disease. There are several pharmacotherapeutics aimed at pulmonary vasodilation. This review highlights the most common agents as well as those on the horizon for the treatment of pulmonary hypertension in the neonate.

Etiology, Diagnosis and Management of Persistent Pulmonary Hypertension of the Newborn in Resource-limited Settings.

Persistent Pulmonary Hypertension of the Newborn (PPHN) is more common in Low and middle income countries (LMICs) due to high incidence of sepsis, perinatal asphyxia and meconium aspiration syndrome. Presence of hypoxic respiratory faillure and greater than 5% difference in preductal and post ductal saturation increases clinical sucipision for PPHN. The availability of Inhaled nitric oxide and extracorporaeal membrane oxygenation is limited but pulmonary vasodilators such as sildenafil are readily available in most LMICs.

Randomized Controlled Trials of Pulmonary Vasodilator Therapy Adjunctive to Inhaled Nitric Oxide for Persistent Pulmonary Hypertension of the Newborn: A Systematic Review.

Inhaled nitric oxide (iNO) is a pulmonary vasodilator considered standard of care to treat persistent pulmonary hypertension of the newborn. However, not all infants respond to iNO. The authors performed a systematic review to examine methodology, outcomes, and challenges of randomized controlled trials testing pulmonary vasodilator medications adjunctive to iNO. The 5 trials identified showed heterogeneity in eligibility criteria and outcomes assessed. No trial achieved recruitment goals, limiting conclusions regarding efficacy, safety, and pharmacology. Trial design consensus and alternative methodologic strategies such as deferred consent, real-world controls, nonrandomized database assessments, and Bayesian statistical approaches are needed.

Inhaled Nitric Oxide in Neonatal Pulmonary Hypertension.

Pivotal trials investigating the use of inhaled nitric oxide (iNO) in the 1990s led to approval by the Food and Drug Administration in 1999. Inhaled nitric oxide is the only approved pulmonary vasodilator for persistent pulmonary hypertension of the newborn (PPHN). Selective pulmonary vasodilation with iNO in near-term and term neonates with PPHN is safe, and targeted use of iNO in less mature neonates with pulmonary hypertension (PH) can be beneficial. This review addresses a brief history of iNO, clinical features of neonatal PH, and the clinical application of iNO.

Photocleavable Visible Light-Triggered Anthraquinone-Derived Water-Soluble Block Copolymer for Peroxynitrite Generation in Cancer Therapy.

We report a facile stimuli-responsive strategy to generate reactive oxygen and nitrogen species (ROS and RNS) in the biological milieu from a photocleavable water-soluble block copolymer under visible light irradiation (427 nm, 2.25 mW/cm2). An anthraquinone-based water-soluble polymeric nitric oxide (NO) donor (BCPx-NO) is synthesized, which exhibits NO release in the range of 40-65 µM within 10 h of photoirradiation with a half-life of 30-103 min. Additionally, BCPx-NO produces peroxynitrite (ONOO-) and singlet oxygen (1O2) under photoirradiation. To understand the mechanism of NO release and photolysis of the functional group under blue light, we prepared a small-molecule anthraquinone-based N-nitrosamine (NOD). The cellular investigation of the effect of spatiotemporally controlled ONOO- and 1O2 generation from the NO donor polymeric nanoparticles in a triple negative breast adenocarcinoma (MDA-MB-231) under visible light irradiation (white light, 5.83 mW/cm2; total dose 31.5 J/cm2) showed an IC50 of 0.6 mg/mL. The stimuli-responsive strategy using a photolabile water-soluble block copolymer employed to generate ROS and RNS in a biological setting widens the horizon for their potential in cancer therapy.

Administering Nitric Oxide (NO) with High Flow Nasal Cannulas: A Simple Method.

Inhaled nitric oxide (iNO) is a pulmonary vasodilator that plays an important clinical ICU role. The administration of iNO is usually performed through an endotracheal tube, but spontaneously breathing patients might also benefit from iNO administration. The use of the non-invasive administration of iNO through high-flow nasal cannula (HFNC) allows for NO delivery in spontaneously breathing patients who still need supplemental oxygen and positive airway pressure. A simple method to administer NO through HFNC is described here using standard commercially available NO administration and HFNC.

[Risks of magistral preparations in pediatrics]. / Risques des préparations magistrales en pédiatrie.

Vasoreactive pulmonary arterial hypertension (PAH) in children is a form of idiopathic PAH that responds to vasoreactive testing with nitric oxide (NO) by a significant decrease of pulmonary vascular resistances and pressure. Oral calcium channel antagonists (CCA) that allow pulmonary arterial vasodilation are the treatment of choice. The therapeutic effect is strongly depending on adequate drug intake. In growing children, drug dose must be adapted to weight. In case of unavailability of low-dose pharmaceutical preparations, officinal formulations become mandatory. Officinal formulations may be related to a multitude of errors at different steps including prescription, transcription, preparation and administration. This may have life-threatening consequences for the child.To illustrate this, we report a case of a compounding error with underdosage of CCA, leading to acute cardiovascular failure in an adolescent with vasoreactive PAH.

L'hypertension artérielle pulmonaire (HTAP) vasoréactive chez l'enfant est une forme d'HTAP idiopathique qui répond au test de vasoréactivité au monoxyde d'azote (NO) par une diminution significative des pressions et résistances vasculaires pulmonaires. Le traitement de choix de cette forme d'HTAP est l'administration d'antagonistes des canaux calciques (ACC) par voie orale. Ce traitement entraîne une vasodilatation artérielle pulmonaire, elle-même étroitement dépendante de la prise adéquate du médicament. Chez les enfants en croissance, la dose du médicament doit être adaptée au poids. De façon générale, en l'absence de préparation à faible dose disponible dans les laboratoires pharmaceutiques, l'utilisation de formulations officinales devient obligatoire. De la prescription à l'administration, en passant par la transcription et la préparation, de nombreuses erreurs humaines et techniques peuvent survenir qui peuvent impacter la morbi-mortalité de l'enfant. Nous rapportons le cas d'une adolescente avec HTAP vasoréactive chez qui une erreur de préparation magistrale avec sous-dosage de l'ACC a conduit à une décompensation cardio-vasculaire aiguë et discutons de mesures préventives potentielles.

In vivo testing of novel nitric oxide-releasing nanoparticles for alleviating heart failure using the zebrafish embryo model.

Heart failure (HF) is a multifactorial, heterogeneous systemic disease that is considered one of the leading causes of death and morbidity worldwide. It is well-known that endothelial dysfunction (ED) plays an important role in cardiac disease etiology. A reduction in the bioavailability of nitric oxide (NO) in the bloodstream leads to vasoconstriction and ED. Many studies indicated diminishment of peripheral arteries vasodilation that is mediated by the endothelium in the of patients with chronic HF. With the advancement of nanomedicine, nanotechnology can provide adequate solutions for delivering exogenous NO with the aid of nanoparticles (NPs) to treat ED. The properties of superparamagnetic iron oxide nanoparticles (SPIONs) enable both passive and active delivery of drugs. This prompted us to investigate the efficacy of our newly-developed hydrogel nanoparticles (NO-RPs) for the delivery and sustained release of NO gas to alleviate cardiac failure and inflammation in the heart failure zebrafish model. The hydrogel NO-RPs incorporate SPIONS and NO precursor. The sustainend release of NO in the NO-RPs (4200 s), overcomes the problem of the short half life of NO in vivo which is expected to ameliorate the reduced NO bioavailabilty, and its consequences in endothelial and cardiac dysfunction. Zebrafish embryos were used as the animal model in this study to determine the effect of SPIONs-loaded NO-RPs on the cardiovascular system. Cardiac failure was induced in 24hpf embryos by exposure to aristolochic acid (AA)(0.25, 0.5 µM) for 8 h, followed by the SPIONs-loaded NO-RPs (0.25, 0.5 mg/ml) for 48 h, experimental groups included: control group which is healthy non treated zebrafish embryos, AA injured zebrafish embryos (HF) model,and NO-RP treated HF zebrafish embryos. Survival rate was assessed at 72hpf. Cardiac function was also evaluated by analyzing cardiac parameters including heartbeat, major blood vessels primordial cardinal vein and dorsal aorta (PCV &DA) diameter, blood flow velocity in PCV & DA vessels, cardiac output, and PCV & DA shear stresses. All cardiac parameters were analyzed with the aid of MicroZebraLab blood flow analysis software from Viewpoint. In addition, we studied the molecular effects of the developed NO-RPs on the mRNA expression of selected pro-inflammatory markers: IL-6, and Cox-2. Our findings demonstrated that the NO-RPs improved the survival rate in the heart failure zebrafish model and reversed heart failure by enhancing blood flow perfusion in Zebrafish embryos, significantly. In addition, RT-PCR results showed that the NO-RPs significantly reduced the expression of pro-inflammatory markers (lL-6&COX-2) in the heart failure zebrafish model. Our study confirmed that the developed SPIONs-loaded NO-RPs are effective tool to alleviate cardiac failure and inflammation in the HF zebrafish model.

Nitric oxide: A potential etiological agent for vaso-occlusive crises in sickle cell disease.

Nitric oxide (NO), a vasodilator contributes to the vaso-occlusive crisis associated with the sickle cell disease (SCD). Vascular nitric oxide helps in vasodilation, controlled platelet aggregation, and preventing adhesion of sickled red blood cells to the endothelium. It decreases the expression of pro-inflammatory genes responsible for atherogenesis associated with SCD. Haemolysis and activated endothelium in SCD patients reduce the bioavailability of NO which promotes the severity of sickle cell disease mainly causes vaso-occlusive crises. Additionally, NO depletion can also contribute to the formation of thrombus, which can cause serious complications such as stroke, pulmonary embolism etc. Understanding the multifaceted role of NO provides valuable insights into its therapeutic potential for managing SCD and preventing associated complications. Various clinical trials and studies suggested the importance of artificially induced nitric oxide and its supplements in the reduction of severity. Further research on the mechanisms of NO depletion in SCD is needed to develop more effective treatment strategies and improve the management of this debilitating disease.

Inhaled nitric oxide therapy for preterm infants after 7 days of age: a scoping review protocol.

INTRODUCTION: Inhaled nitric oxide (iNO) use is recommended for persistent pulmonary hypertension of the newborn in term and late preterm infants. Recently, iNO therapy to prevent bronchopulmonary dysplasia (BPD) or rescue for hypoxic respiratory failure and pulmonary hypertension secondary to BPD has increasingly been used in preterm infants after 7 days of postnatal age (in the postacute phase), despite its off-label use. However, the initiation criteria of iNO therapy for preterm infants in the postacute phase are varied. The aim of this scoping review is to identify the clinical and/or echo findings at the initiation of iNO therapy in preterm infants in the postacute phase. METHODS AND ANALYSIS: We will search PubMed, Embase and the Japanese database 'Ichushi.' The following studies will be included in the review: randomised controlled trials, prospective/retrospective cohort studies, case-control studies and case series on iNO therapy for preterm infants in the postacute phase; studies published between January 2003 and August 2023; studies conducted in developed countries and studies written in English or Japanese. We will independently screen, extract and chart data using the population-concept-context framework following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. We will summarise the characteristics and findings of the included studies. ETHICS AND DISSEMINATION: Obtaining an institutional review board approval is not required because of the nature of this review. A final report of review findings will be published and disseminated through a peer-reviewed journal and presentation at relevant conferences. TRIAL REGISTRATION NUMBER: UMIN000051498.

Association between fractional exhaled nitric oxide and therapeutic adherence to controller management in pediatric asthma patients.

OBJECTIVES: Guidelines for asthma management recommend, before establishing additional therapeutic behaviors, to confirm correct use and adequate therapeutic adherence to treatment. Evidence exists on the use of fractional exhaled nitric oxide (FeNO) values for monitoring therapeutic adherence in adults. It is important to establish whether there is a correlation between FeNO and therapeutic adherence in children. This study aims to provide new knowledge about the relationship between FeNO and therapeutic adherence in asthmatic children. MATERIALS AND METHODS: Analytical cross-sectional study including asthma patients 5-18 years of age, attending follow-up at Hospital Militar Central (HMC) between May and November 2022 in Colombia. A sociodemographic survey was carried out, followed by the Pediatric Inhaler Adherence Questionnaire (PIAQ), and asthma control test (ACT) or childhood asthma control test (cACT). We defined adequate therapeutic adherence as not missing a single application of inhaled steroids in the last 15 days according to PIAQ. A poisson regression model was carried out including relevant predictors for therapeutic adherence such as FeNO values, age, tobacco exposure at home, atopy, and time since initiation of use of inhaled controller. RESULTS: Eighty-two children with a median age of 10 years (interquartile range: 7-12 years) were included. Adequate therapeutic adherence was reported by 68.3%. After adjusting for age, sex, exposure to cigarette smoke, duration of controller therapy, and atopy, FeNO < 20 ppb was independently associated with adequate therapeutic adherence (RR = 1.5, p = .04, 95% confidence interval: 1.03-2.19). CONCLUSIONS: FeNO values seem to be useful to identify pediatric patients with asthma who have adequate adherence to inhaled steroids in a MIC.

Saying no to SARS-CoV-2: the potential of nitric oxide in the treatment of COVID-19 pneumonia.

Nitric oxide (NO), a gaseous free radical produced from L-arginine catalyzed by NO synthase, functions as an important signaling molecule in the human body. Its antiviral activity was confirmed in the 1990s, and has been studied more extensively since the outbreak of the SARS pandemic in 2003. In the fight against the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, some recent studies have revealed the potential of NO in the treatment of coronavirus disease 2019 (COVID-19). The progress in this field, including several noteworthy clinical trials of inhaled NO for the treatment of COVID-19 and the emergency approval of NO nasal spray by the regulatory agencies of Israel, Bahrain, Thailand and Indonesia for the treatment of COVID-19 pneumonia, offers a new perspective for addressing the raging coronavirus infection and greatly broadens the clinical application of NO therapy. This review aims to explore the underlying molecular mechanisms of NO-based therapy against SARS-CoV-2, including direct viral inhibition, immune regulation, and protection against pulmonary and cardiovascular symptoms. Furthermore, the potential therapeutic applications of inhaled NO, NO donors and drugs involved in the NO pathway are discussed. In the context of a global vaccination campaign and newly proposed strategy of "coexistence with COVID-19," the advantages of NO therapies as symptomatic and adjuvant treatments are expected to deliver breakthroughs in the treatment of COVID-19.

The early use of inhaled nitric oxide in premature infants requiring respiratory support.

Background: Earlier studies on the use of inhaled nitric oxide (iNO) for premature infants born at <34 weeks of gestation requiring respiratory support did not provide conclusive evidence of benefit. National guidelines generally discouraged the use in this population. More recent national guidelines endorsed the use of iNO in premature infants with hypoxic respiratory failure (HRF) associated with persistent pulmonary hypertension of the newborn (PPHN).Recent Studies: Two recently published observational studies evaluated the effect of administering iNO on oxygenation in the first week of life. These studies compared premature infants born at the gestational age (GA) of <34 weeks with HRF associated with PPHN to term and late preterm infants born at the GA of ≥34 weeks who received iNO. Both studies showed a similar effect of iNO on oxygenation in the two infant cohorts. The response rate in the premature infant cohort was 59% in the first study and 90% in the second. The mean response time was 9.2 h and 10.3 h, and the mean duration of therapy was 3.5 days and 8.2 days, respectively.Conclusion: The results of these studies support a trial of iNO in premature infants with persistent hypoxia despite optimum respiratory support. Obtaining a timely echocardiogram to exclude cardiac diseases and diagnose PPHN is logistically challenging for many clinicians, thus, a clinical diagnosis of PPHN might have to be made in these situations. Questions remain regarding the optimum dose of iNO and the duration of the initial iNO trial in these patients.KEY MESSAGESIn the most recently published studies, the improvement of oxygenation in iNO-treated infants born at <34 weeks of gestation with HRF and PPHN physiology was as effective as in infants born ≥34 weeks.These studies provide evidence supporting a trial of iNO in the subpopulation of premature infants with HRF associated with PPHN.