Nitric Oxide Deficiency Research Articles

The effect of the long-term inhibition of hydrogen sulfide production on the reactivity of the cardiovascular system in Wistar rats.

In this study, we investigated the blood pressure responses of the peripheral bed invivo after chronic hydrogen sulfide (H2S) inhibition combined with acute nitric oxide (NO) deficiency. We also evaluated the role of endogenously produced H2S in the vasoactive responses of large- and medium-sized arteries invitro. Changes in integrated blood pressure responses were measured after chronic inhibition of cystathionine-γ-lyase, an enzyme involved in H2S synthesis, with DL-propargylglycine (PPG), and acute inhibition of NO-synthase with nonspecific L-NG-nitro arginine methyl ester (L-NAME), and vasoactive responses of the thoracic aorta (TA) and mesenteric artery (MA) were investigated after acute incubation with PPG. We confirmed that chronic H2S deficiency had no effect on blood pressure, heart trophycity, noradrenaline, and H2S donor vasoactive responses but induced renal hypertrophy and a decrease in acetylcholine-induced hypotensive and L-NAME-induced hypertensive responses. Acute H2S deficiency led to an increase in basal tone (MA) or active tone (TA), whereas endothelium-dependent vasorelaxation remained unaffected. Long-term administration of PPG revealed a role of endogenous H2S in the bioavailability of endothelial NO in peripheral arteries. When both H2S and NO were lacking, the activation of H2S-independent compensatory mechanisms plays an important role in maintaining the vasodilator responses of the cardiovascular system.

Role of heme oxygenase in the regulation of the renal hemodynamics in a model of sex-dependent programmed hypertension by maternal diabetes.

Intrauterine programming of cardiovascular and renal function occurs in diabetes because of the adverse maternal environment. Heme oxygenase 1 (HO-1) and -2 (HO-2) exert vasodilatory and antioxidant actions, particularly in conditions of elevated HO-1 expression or deficient nitric oxide levels. We evaluated whether the activity of the heme-HO system is differentially regulated by oxidative stress in the female offspring of diabetic mothers, contributing to the improved cardiovascular function in comparison with males. Diabetes was induced in pregnant rats by a single dose of streptozotocin (STZ, 50 mg/kg ip) in late gestation. Three-month-old male offspring from diabetic mothers (MODs) exhibited higher blood pressure (BP), higher renal vascular resistance (RVR), worse endothelium-dependent response to acetylcholine (ACH), and an increased constrictor response to phenylephrine (PHE) compared with those in age-matched female offspring of diabetic mothers (FODs), which were abolished by chronic tempol (1 mM) treatment. In anesthetized animals, stannous mesoporphyrin (SnMP; 40 µmol/kg iv) administration, to inhibit HO activity, increased RVR in FODs and reduced glomerular filtration rate (GFR) in MODs, without altering these parameters in control animals. When compared with MODs, FODs showed lower nitrotirosyne levels and higher HO-1 protein expression in renal homogenates. Indeed, chronic treatment with tempol in MODs prevented elevations in nitrotyrosine levels and the acute renal hemodynamics response to SnMP. Then, maternal diabetes results in sex-specific hypertension and renal alterations associated with oxidative stress mainly in adult male offspring, which are reduced in the female offspring by elevation in HO-1 expression and lower oxidative stress levels.

Nitric Oxide on Pathophysiology of SARS-CoV 19: Toward Possible Role of Acupuncture Treatment

The ongoing outbreak of COVID-19 has quickly become a daunting challenge to global health. In the absence of satisfied therapy, effective treatment interventions are urgently needed. Previous studies have demonstrated that acupuncture is effective at relieving common symptoms of COVID-19 including breathlessness, nausea, insomnia, leukopenia, fatigue, vomiting, and abdominal pain. Experiments have shown that nitric oxide (NO) inhibits the replication cycle of severe acute respiratory syndrome (SARS) coronavirus with similar structures of COVID-19. Increase in level of NO by using NO gas inhalation has been shown to restore lung function by reducing airway resistance and improving virus-induced lung infections in SARS patients. Recent case report showed that a medical acupuncturist with symptoms consistent with severe COVID pneumonia achieved full recovery by self-administered medical acupuncture and cupping therapy at home. Clinical features and pathophysiology demonstrated that NO deficiency and endothelial dysfunction contribute to the development of COVID-19. Several studies from different groups consistently demonstrated that acupuncture increases NO synthase expression and induces an elevation of NO production and release in plasma and the local skin regions in both animals and humans. It is suggested that exogenous NO supplies or interventions that induce increasing levels of NO can play an important role in protective effects against inflammation and acute lung injury. This article reviews the rationale for mechanisms of NO induction induced by acupuncture in the possible treatment of COVID-19 and highlights its potential for contributing to better clinical outcomes and improving future clinical studies of acupuncture on treatment of COVID-19.

Compensatory role of endogenous sulfur dioxide in nitric oxide deficiency-induced hypertension

ObjectiveThis study aimed to determine the communicational pattern of gaseous signaling molecules sulfur dioxide (SO2) and nitric oxide (NO) between vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs), and elucidate the compensatory role and significance of endogenous SO2 in the development of hypertension due to NO deficiency. Approach and resultsBlood pressure was monitored by the tail-cuff and implantable physiological signal telemetry in L-nitro-arginine methyl ester (l-NAME)-induced hypertensive mice, and structural alterations of mouse aortic vessels were detected by the elastic fiber staining method. l-NAME-treated mice showed decreased plasma NO levels, increased SO2 levels, vascular remodeling, and increased blood pressure, and application of l-aspartate-β-hydroxamate, which inhibits SO2 production, further aggravated vascular structural remodeling and increased blood pressure. Moreover, in a co-culture system of HAECs and HASMCs, NO from HAECs did not influence aspartate aminotransferase (AAT)1 protein expression but decreased AAT1 activity in HASMCs, thereby resulting in the inhibition of endogenous SO2 production. Furthermore, NO promoted S-nitrosylation of AAT1 protein in HASMCs and purified AAT1 protein. Liquid chromatography with tandem mass spectrometry showed that the Cys192 site of AAT1 purified protein was modified by S-nitrosylation. In contrast, dithiothreitol or C192S mutations in HASMCs blocked NO-induced AAT1 S-nitrosylation and restored AAT1 enzyme activity. ConclusionEndothelium-derived NO inhibits AAT activity by nitrosylating AAT1 at the Cys192 site and reduces SO2 production in HASMCs. Our findings suggest that SO2 acts as a compensatory defense system to antagonize vascular structural remodeling and hypertension when the endogenous NO pathway is disturbed.

Intrauterine L-NAME Exposure Weakens the Development of Sympathetic Innervation and Induces the Remodeling of Arterial Vessels in Two-Week-Old Rats.

Nitric oxide (NO) has been shown to stimulate differentiation and increase the survival of ganglionic sympathetic neurons. The proportion of neuronal NOS-immunoreactive sympathetic preganglionic neurons is particularly high in newborn rats and decreases with maturation. However, the role of NO in the development of vascular sympathetic innervation has never been studied before. We tested the hypothesis that intrauterine NO deficiency weakened the development of vascular sympathetic innervation and thereby changed the contractility of peripheral arteries and blood pressure level in two-week-old offspring. Pregnant rats consumed NOS inhibitor L-NAME (250 mg/L in drinking water) from gestational day 10 until delivery. Pups in the L-NAME group had a reduced body weight and blood level of NO metabolites at 1–2 postnatal days. Saphenous arteries from two-week-old L-NAME offspring demonstrated a lower density of sympathetic innervation, a smaller inner diameter, reduced maximal active force and decreased α-actin/β-actin mRNA expression ratio compared to the controls. Importantly, pups in the L-NAME group exhibited decreased blood pressure levels before, but not after, ganglionic blockade with chlorisondamine. In conclusion, intrauterine L-NAME exposure is followed by the impaired development of the sympathetic nervous system in early postnatal life, which is accompanied by the structural and functional remodeling of arterial blood vessels.

Long Term Sodium Nitrate Administration Positively Impacts Metabolic and Obesity Indices in Ovariectomized Rats

In postmenopausal women, nitric oxide (NO) deficiency is associated with obesity and type 2 diabetes (T2D). This study aims at determining the long-term effects of low-dose nitrate administration on metabolic and obesity indices in ovariectomized (OVX) rats. OVX rat model was induced using the two dorsolateral skin incision method. Two months after ovariectomy, rats were divided into three groups (n=10/group): Control, OVX, and OVX+nitrate, and the latter received sodium nitrate at a dose of 100 mg/L in their drinking water for nine months. Fasting serum glucose and lipid profile were measured every month. A glucose tolerance test was performed at months 1, 3, and 9 (the end of the study). Obesity indices were calculated, and histological analyses were performed on the gonadal adipose tissues at month 9. OVX rats had impaired fasting glucose, glucose intolerance, and dyslipidemia with higher obesity indices at month 9. Nitrate improved glucose and lipid metabolism in OVX rats and decreased body weight (6.9%), body mass index (12.5%), Lee index (5.4%), adiposity index (23.9%), abdominal circumference (10.5%), and thoracic circumference (17.1%). Also, nitrate decreased adipocyte area by 49% and increased adipocyte density by 193% in gonadal adipose tissue. Long-term low-dose nitrate administration improves glucose and lipid metabolism in OVX rats in association with decreasing OVX-induced adiposity, increasing adipocyte density, and decreasing adipocyte area. These findings provide support for a potential therapeutic role of nitrate in postmenopausal women with some features of metabolic syndrome.

Clinical Characteristics of Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes.

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, a maternally inherited mitochondrial disorder, is characterized by its genetic, biochemical and clinical complexity. The most common mutation associated with MELAS syndrome is the mtDNA A3243G mutation in the MT-TL1 gene encoding the mitochondrial tRNA-leu(UUR), which results in impaired mitochondrial translation and protein synthesis involving the mitochondrial electron transport chain complex subunits, leading to impaired mitochondrial energy production. Angiopathy, either alone or in combination with nitric oxide (NO) deficiency, further contributes to multi-organ involvement in MELAS syndrome. Management for MELAS syndrome is amostly symptomatic multidisciplinary approach. In this article, we review the clinical presentations, pathogenic mechanisms and options for management of MELAS syndrome.

Abstract P275: Deletion Of Endothelial Leptin Receptor Elevates Blood Pressure And Impairs Endothelial-dependent Relaxation Via Upregulation Of Endothelial Glycolytic Enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3)

The adipokine leptin plays a crucial role in blood pressure (BP) regulation notably by exerting pressor effects centrally via sympatho-activation and depressor effects via direct activation of its receptor (LepR) peripherally resulting in nitric oxide (NO)-mediated vasodilation. However, the predominant effects and cell type responsible for leptin-mediated NO production is not clearly understood. Herein, we examined the effect of selective deletion of LepR in endothelial cells (LepR EC-/- , KO) on BP and vascular function. BP recording via radiotelemetry in male KO and WT (LepR EC+/+ ) mice revealed significant increases in diastolic and mean arterial pressure in KO mice (DBP, WT: 90.2±2.1 vs. KO: 100.1±3.6; MAP, WT: 105.7±2.1 vs. KO: 113.7±2.6 mmHg, n=5, p<0.05). There was no difference in Systolic blood pressure or heart rate between KO and WT. Leptin infusion (0.9mg/kg/day,7 days) elicits a significant increase in BP of WT but not KO mice (DBP, WT: 89.2± 2.6 vs WT+Leptin 95.7±3.3; MAP, WT: 104 ±2.8 vs WT+Leptin: 110 ±2.7, n=5, p<0.05). We quantified sympathetic contribution to BP elevation by measuring BP response to glanglionic blockade (Hexamethonium). At baseline, KO mice exhibited a lower BP response than WT supporting a reduced neurogenic control of BP regulation in KO mice. Vascular contribution to high BP was investigated using wire myography in thoracic aorta. LepR deficiency impaired endothelial-dependent relaxation (EDR) to acetylcholine (n=7, p<0.05). L-NAME completely abolished EDR in KO and WT indicating that EC LepR deficiency reduced NO bioavailability. Recent evidence presents PFKFB3-mediated EC glycolysis as a new regulator of endothelial homeostasis. We found that aortic EC from KO exhibited increased PFKFB3 mRNA expression (p=0.065) and PFKFB3 inhibition restored EDR in KO. Remarkably, overexpression of PFKFB3 increased EC glycolysis in vitro and impaired EDR in WT aortic rings ex vivo . Collectively, our data suggest that impaired endothelial leptin receptor signaling induces a PFKFB3-dependent hyper-glycolytic phenotype resulting in NO deficiency and endothelial dysfunction that predisposes to higher BP regardless the reduced sympatho-activation which might prevent the increase in BP induced by exogenous leptin.

Nitric oxide role in pathogenesis and treatment of cardio-vascular diseases (literature review)

Literature data concerning the role of endothelium and nitric oxide in the pathogenesis of cardiovascular diseases, administration of L-arginine as a part of a comprehensive therapy of patients suffering from essential hypertension (EH) and ischemic heart disease (IHD) are cited.Objective: to systematize current literature data concerning the role of endothelium and nitric oxide in the pathogenesis of cardiovascular diseases, clinical experience of L-arginine administration in patients with EH and IHD. Conclusion. Nowadays endothelial dysfunction conception is defined with insufficient production of nitric oxide as a central part of EH and IHD pathogenesis. Nitric oxide deficiency occurring with cardiovascular diseases can be compensated by means of NO donors.

Nitric Oxide Deficiency in Mitochondrial Disorders: The Utility of Arginine and Citrulline.

Mitochondrial diseases represent a growing list of clinically heterogeneous disorders that are associated with dysfunctional mitochondria and multisystemic manifestations. In spite of a better understanding of the underlying pathophysiological basis of mitochondrial disorders, treatment options remain limited. Over the past two decades, there is growing evidence that patients with mitochondrial disorders have nitric oxide (NO) deficiency due to the limited availability of NO substrates, arginine and citrulline; decreased activity of nitric oxide synthase (NOS); and NO sequestration. Studies evaluating the use of arginine in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) presenting with stroke-like episodes showed symptomatic improvement after acute administration as well as a reduction in the frequency and severity of stroke-like episodes following chronic use. Citrulline, another NO precursor, was shown through stable isotope studies to result in a greater increase in NO synthesis. Recent studies showed a positive response of arginine and citrulline in other mitochondrial disorders besides MELAS. Randomized-controlled studies with a larger number of patients are warranted to better understand the role of NO deficiency in mitochondrial disorders and the efficacy of NO precursors as treatment modalities in these disorders.

Intrauterine Nitric Oxide Deficiency Weakens Differentiation of Vascular Smooth Muscle in Newborn Rats.

Nitric oxide (NO) deficiency during pregnancy is a key reason for preeclampsia development. Besides its important vasomotor role, NO is shown to regulate the cell transcriptome. However, the role of NO in transcriptional regulation of developing smooth muscle has never been studied before. We hypothesized that in early ontogeny, NO is important for the regulation of arterial smooth muscle-specific genes expression. Pregnant rats consumed NO-synthase inhibitor L-NAME (500 mg/L in drinking water) from gestational day 10 till delivery, which led to an increase in blood pressure, a key manifestation of preeclampsia. L-NAME reduced blood concentrations of NO metabolites in dams and their newborn pups, as well as relaxations of pup aortic rings to acetylcholine. Using qPCR, we demonstrated reduced abundances of the smooth muscle-specific myosin heavy chain isoform, α-actin, SM22α, and L-type Ca2+-channel mRNAs in the aorta of newborn pups from the L-NAME group compared to control pups. To conclude, the intrauterine NO deficiency weakens gene expression specific for a contractile phenotype of arterial smooth muscle in newborn offspring.

Nitric oxide releasing nanofibrous Fmoc-dipeptide hydrogels for amelioration of renal ischemia/reperfusion injury

Renal ischemia/reperfusion (I/R) injury is responsible for significant mortality and morbidity during renal procedures. Nitric oxide (NO) deficiency is known to play a crucial role in renal I/R injury; however, low stability and severe toxicity of high concentrations of NO have limited its applications. Herein, we developed an in-situ forming Fmoc-dipheylalanine hydrogel releasing s-nitroso-n-acetylpenicillamine (FmocFF-SNAP) for renal I/R injury. Fmoc-FF hydrogel comprising of β-sheet nanofibers was prepared through the pH-titration method. It was then characterized by electron microscopy, pyrene assay, and circular dichroism techniques. Mechanical properties of Fmoc-FF hydrogel (thixotropy and syringeability) were investigated by oscillatory rheology and texture analysis. To assess the therapeutic efficiency in the renal I/R injury model, expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) was measured in various samples (different concentrations of free SNAP and FmocFF-SNAP, unloaded Fmoc-FF, and sham control) by real-time RT-PCR, ROS production, serum biomarkers, and histopathological evaluations. According to the results, Fmoc-FF self-assembly in physiologic conditions led to the formation of an entangled nanofibrous and shear-thinning hydrogel. FmocFF-SNAP exhibited a sustained NO release over 7 days in a concentration-dependent manner. Importantly, intralesional injection of FmocFF-SNAP caused superior recovery of renal I/R injury when compared to free SNAP in terms of histopathological scores and renal function indices (e.g. serum creatinine, and blood urea nitrogen). Compared to the I/R control group, biomarkers of oxidative stress and iNOS expression were significantly reduced possibly due to the sustained release of NO. Interestingly, the eNOS expression showed a significant enhancement reflecting the regeneration of the injured endothelial tissue. Thus, the novel FmocFF-SNAP can be recommended for the alleviation of renal I/R injury.

Multiple-Ascending-Dose Study of the Soluble Guanylate Cyclase Stimulator, IW-1701, in Healthy Subjects

▪Background: Nitric oxide (NO), a key regulator of vascular health, modulates smooth muscle tone and blood pressure, inhibits vascular smooth muscle proliferation, and suppresses inflammation and platelet activation. These protective functions are mediated by soluble guanylate cyclase (sGC), a signaling enzyme that catalyzes the formation of cyclic guanosine monophosphate (cGMP) in response to NO binding. The compromised vascular health characteristic of the hemoglobinopathies may in part be due to deficient NO bioavailability and inadequate sGC-cGMP signaling. IW-1701 is an orally available sGC stimulator that binds to sGC and enhances NO-sGC-cGMP signaling.Methods: A Phase 1b placebo-controlled, randomized, multiple-ascending-dose study was conducted to assess safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (blood pressure, heart rate, platelet function, and plasma cGMP) of IW-1701 in healthy subjects. Five successive cohorts of 11 subjects each (8 active and 3 placebo) were randomized. The first 3 cohorts received 7 days of repeated once-daily (QD) doses of 1-, 2- or 5-mg IW-1701 respectively, and the last 2 cohorts received 7 days of lead-in QD doses of 3 mg followed by 7 days of up-titrated QD doses of 5 or 6 mg, respectively.Results: IW-1701 doses ranging from 1 to 6 mg were tolerated and no safety concerns were identified. There were no serious adverse events (SAEs), severe adverse events (AEs), or withdrawals due to AEs. All AEs were mild or moderate, most resolved on the day of onset. Among the 40 subjects who received IW-1701 for 7 consecutive days, the most common AEs were tachycardia and headache (each reported in 7 subjects), and hypotension and nausea (each reported in 3 subjects). Among the 16 subjects who received an up-titrated dose of IW-1701 for 7 additional days, headache was the only AE reported in >1 subject (2 subjects). IW-1701 was rapidly absorbed, with median Tmax achieved from 2 to 4 hours postdose. Systemic exposure to IW-1701 was less than dose proportional after a single dose (Cmax slope, 0.701 [90% CI, 0.578-0.824] and AUCtau slope, 0.833 [90% CI, 0.726-0.939]) and was dose proportional after 7 days of QD dosing (Cmax slope, 1.01 [90% CI, 0.873-1.14] and AUCtau slope, 1.03 [90% CI, 0.892-1.17]). Intersubject variability in PK was low to moderate (AUCtau %CV range, 10.6-39.1%). The accumulation ratio (based on RAUC) ranged from 1.95 to 2.63 across doses of 1-, 2-, 3-, and 5-mg IW-1701 after 7 days of QD dosing. Mean CL/F (apparent total body clearance) and Vz/F (apparent volume of distribution) ranged from 1080 to 1520 mL/h and 49.4 to 58.9 L, respectively. Mean terminal t1/2 was 30 hours, which is consistent with a QD dosing regimen. After 7 days of QD dosing, least squares mean changes from baseline in 24-hour ambulatory systolic blood pressure (±SE) (in cohort order) were -1.17±1.24 (placebo), -2.98±1.80 (1 mg), -5.37±1.71 (2 mg), -6.67±1.69 (5 mg), -6.55±1.95 (3 mg), and -4.98±1.68 mmHg (3 mg). After 14 days of QD dosing in the 2 cohorts that received up-titrated doses, the least squares mean changes from baseline in 24-hour ambulatory systolic blood pressure (±SE) were -1.51±2.42 (placebo), -6.85±2.03 (5 mg), and -8.64±2.08 mmHg (6 mg). Plasma cGMP levels were highly variable; in general, mean plasma cGMP levels were increased from baseline at dose levels ≥3 mg IW-1701. There were no clinically meaningful changes from baseline in platelet function assessment by PFA-100® at any dose level.Conclusion: IW-1701 was tolerated in healthy subjects with only mild and moderate AEs. Common AEs were consistent with the effects of sGC stimulation. Lead-in dosing with a lower dose (3 mg) appeared to improve the tolerability of higher doses (5 and 6 mg). The PK of repeat IW-1701 dosing was dose proportional with low-to-moderate intersubject variability and half-life consistent with QD dosing. Pharmacodynamic results, including blood pressure and plasma cGMP levels, demonstrated target engagement. Clinical evaluation of IW-1701 in diseases associated with NO deficiency, including sickle cell disease and achalasia, are planned or ongoing.– The authors gratefully acknowledge the early contributions of Bernard J. Lavins. – DisclosuresMittleman:Ironwood Pharmaceuticals: Employment, Equity Ownership. Wilson:Ironwood Pharmaceuticals: Employment, Equity Ownership. Sykes:Ironwood Pharmaceuticals: Employment, Equity Ownership. Mihova:Ironwood Pharmaceuticals: Employment, Equity Ownership. Chickering:Ironwood Pharmaceuticals: Employment, Equity Ownership. Hall:Ironwood Pharmaceuticals: Employment, Equity Ownership. Milne:Ironwood Pharmaceuticals: Employment, Equity Ownership. Currie:Ironwood Pharmaceuticals: Employment, Equity Ownership. Chien:Ironwood Pharmaceuticals: Employment, Equity Ownership.

Tumor Necrosis Factor‐Alpha Receptor Type‐1 Protein Level Decreases in Renal Cortical But Not in Medullary Tissue During High Salt Intake in Nitric Oxide Deficient Mice

Tumor necrosis factor-alpha (TNFα) is a pro-inflammatory cytokine that is involved in renal injury associated with salt-sensitive hypertension (SSH). In the kidney, TNFα receptor type 1 (TNFR1) activation induces natriuresis, suggesting its’ counter-regulatory role in SSH opposing salt retention. We hypothesize that TNFR1 activity in the kidney is reduced in nitric oxide (NO) deficient condition to facilitate induction of SSH. Experiments were performed in intact (C57BL6 strain) and in 2 models of NO deficient mice: a) chronically treated with NO synthase inhibitor, nitro-L-arginine methyl ester (L-NAME; 0.05 mg/min/g by osmotic mini-pump), b) eNOS gene knockout (KO) mice, which were fed either normal (NS; 0.4% NaCl) or HS (4% NaCl) containing diet for 4 weeks (n=6-7 in each group). Systemic blood pressure (SBP) was measured using tail-cuff plethysmography. The kidneys were isolated and processed for tissue analysis at the end of the experiment. The protein expression of TNFR1 in renal (cortical and medullary) tissues collected from these experimental mice was analyzed using the Western Blot technique. Protein concentration was determined (BCA Assay) using appropriate TNFR1 and GAPDH antibodies. The blot image was quantified with Image J software. HS intake alone did not alter mean SBP in intact mice (NS, 76 ±2.1 vs HS, 78 ±1.4 mmHg) but increased in L-NAME treated mice (104 ±2.8 mmHg) and in eNOSKO mice (107±3.6 mmHg). The quantitative immunoblot analysis showed that TNFR1 protein level (measured as band intensity density with Image -J) was lower in renal cortical (43.9±9.0 vs 110.7±29.8; P<0.05) but not in medullary tissues (114.4±15.5 vs 128.4±97.1; P=n.s.) in L-NAME treated mice compared to untreated control mice during HS intake condition. The intensity of TNFR1 immunoblot analysis in eNOSKO mice also showed showed the similar results (cortical, 23.7 ± 5.0 vs 110.7±29.8; P<0.001 and medullary, 73.6 ±20.8 vs 128.4±97.1; P=n.s). These data indicate that TNFR1 activity is downregulated in the renal cortical tissues in the condition of NO deficiency. Such downregulation of TNFR1 activity in the renal tubules endowed in cortical tissues (proximal and distal convoluted tubules) would minimize sodium excretion during HS intake leading to the development of SSH in NO deficient conditions.

Cardiac Protection by Oral Sodium Thiosulfate in a Rat Model of L-NNA-Induced Heart Disease.

Hypertension contributes to cardiac damage and remodeling. Despite the availability of renin-angiotensin system inhibitors and other antihypertensive therapies, some patients still develop heart failure. Novel therapeutic approaches are required that are effective and without major adverse effects. Sodium Thiosulfate (STS), a reversible oxidation product of hydrogen sulfide (H2S), is a promising pharmacological entity with vasodilator and anti-oxidant potential that is clinically approved for the treatment of calciphylaxis and cyanide poisoning. We hypothesized that Sodium Thiosulfate improves cardiac disease in an experimental hypertension model and sought to investigate its cardioprotective effects by direct comparison to the ACE-inhibitor lisinopril, alone and in combination, using a rat model of chronic nitric oxide (NO) deficiency. Systemic nitric oxide production was inhibited in Sprague Dawley rats by administering N-ω-nitro-l-arginine (L-NNA) with the food for three weeks, leading to progressive hypertension, cardiac dysfunction and remodeling. We observed that STS, orally administered via the drinking water, ameliorated L-NNA-induced heart disease. Treatment with STS for two weeks ameliorated hypertension and improved systolic function, left ventricular hypertrophy, cardiac fibrosis and oxidative stress, without causing metabolic acidosis as is sometimes observed following parenteral administration of this drug. STS and lisinopril had similar protective effects that were not additive when combined. Our findings indicate that oral intervention with a H2S donor such as STS has cardioprotective properties without noticeable side effects.

Maternal resveratrol therapy protected adult rat offspring against hypertension programmed by combined exposures to asymmetric dimethylarginine and trimethylamine-N-oxide

Resveratrol, a phytochemical, has shown antioxidant properties and potential benefits in hypertension. Asymmetric dimethylarginine (ADMA)-related nitric oxide deficiency and gut microbiota-derived metabolite trimethylamine-N-oxide (TMAO) have been linked to hypertension. We aimed to test whether maternal resveratrol therapy would protect adult offspring against hypertension programmed by prenatal exposure to ADMA and TMAO. Pregnant Sprague-Dawley rats received ADMA 10 mg/kg/day (A), TMAO 0.65 mg/hr (T), ADMA+TMAO (AT), or vesicle (CV). One group of ADMA+TMAO-exposed rats received 50 mg/L of resveratrol in drinking water during pregnancy and lactation periods (ATR). Male offspring (n = 8/group) were assigned to five groups: CV, A, T, AT, and ATR. Rats were killed at 12 weeks of age. ADMA exposure caused the elevation of blood pressure in 12-week-old male offspring, which was exacerbated by TMAO exposure. Treatment with resveratrol rescued hypertension programmed by combined ADMA and TMAO exposure. This was accompanied by alterations in the compositions of gut microbiota and increased fecal butyrate levels. Both the abundance of the butyrate-producing genera Lachnospiraceae and Ruminococcaceae were augmented by resveratrol. Meanwhile, resveratrol therapy significantly increased the abundance of the Cyanobiaceae and Erysipelotrichaceae families. Moreover, the protective effects of resveratrol were related to the mediation of the renin-angiotensin system . Our data provide new insights into the protective mechanisms of resveratrol against hypertension programmed by ADMA and TMAO, including regulation of gut microbiota and their metabolites, the renin-angiotensin system, and nitric oxide pathway. Resveratrol might be a potential reprogramming strategy to protect against the hypertension of developmental origins.

Increase in Bioavailability of Nitric Oxide After Renal Denervation Improves Kidney Function in Sheep With Hypertensive Kidney Disease

[Figure: see text].

Nitric oxide and bone: The phoenix rises again.

The involvement of nitric oxide (NO) in preventing bone loss has long been hypothesized, but despite decades of research the mechanisms remain obscure. In this issue of the JCI, Jin et al. explored NO deficiency using human cell and mouse models that lacked argininosuccinate lyase (ASL), the enzyme involved in synthesizing arginine and NO production. Osteoblasts that did not express ASL produced less NO and failed to differentiate. Notably, in the context of Asl deficiency, heterozygous deletion of caveolin 1, which normally inhibits NO synthesis, restored NO production, osteoblast differentiation, glycolysis, and bone mass. These experiments suggest that ASL regulates arginine synthesis in osteoblasts, which leads to enhanced NO production and increased glucose metabolism. After a period when research slowed, these studies, like the legendary phoenix, renew the exploration of NO in bone biology, and provide exciting translational potential.

Addition of vaginal isosorbide mononitrate for labor induction in pregnancies complicated by hypertensive diseases of pregnancy: a randomized controlled trial

Pregnancies complicated by hypertensive disease of pregnancy often require labor induction. Rates of cesarean delivery range from 15% to 60% in this population. Nitric oxide deficiency has been shown to underlay the pathophysiology of preeclampsia, and nitric oxide promotes cervical ripening. We hypothesized that addition of vaginal isosorbide mononitrate for labor induction could decrease the rate of cesarean delivery in pregnancies with hypertensive disease of pregnancy. This study was a double-blind, placebo-controlled, randomized trial of patients with singleton pregnancy at ≥24 weeks' gestation undergoing labor induction for hypertensive diseases of pregnancy between November 2017 and February 2020. Participants were eligible if their Bishop score was <6 and if their cervical dilation was ≤2 cm. In addition, participants received up to 3 doses of 40 mg isosorbide mononitrate in addition to misoprostol for labor induction. Labor management was per healthcare provider preference. The primary outcome was rate of cesarean delivery. Secondary outcomes included the length of labor and frequency of intrapartum adverse events, including the use of intrapartum antihypertensive agents. 89 women were randomized to the isosorbide mononitrate group, and 87 women were randomized to the placebo group. Cesarean delivery rates were similar in both groups (32.6% vs 25.3%; relative risk, 1.29; 95% confidence interval, 0.81-2.06; P=.39). Maternal headache was increased in patients exposed to isosorbide mononitrate (42.7% vs 31%; relative risk, 1.52; 95% confidence interval, 1.04-2.23; P=.04). Clinical chorioamnionitis was increased in the placebo group (0% vs 8%; P=.02). Secondary outcomes were similar between groups. The addition of vaginal isosorbide mononitrate for labor induction in pregnancies complicated by hypertensive disease of pregnancy did not result in fewer cesarean deliveries.

Targeting the Renin-Angiotensin-Aldosterone System to Prevent Hypertension and Kidney Disease of Developmental Origins.

The renin-angiotensin-aldosterone system (RAAS) is implicated in hypertension and kidney disease. The developing kidney can be programmed by various early-life insults by so-called renal programming, resulting in hypertension and kidney disease in adulthood. This theory is known as developmental origins of health and disease (DOHaD). Conversely, early RAAS-based interventions could reverse program processes to prevent a disease from occurring by so-called reprogramming. In the current review, we mainly summarize (1) the current knowledge on the RAAS implicated in renal programming; (2) current evidence supporting the connections between the aberrant RAAS and other mechanisms behind renal programming, such as oxidative stress, nitric oxide deficiency, epigenetic regulation, and gut microbiota dysbiosis; and (3) an overview of how RAAS-based reprogramming interventions may prevent hypertension and kidney disease of developmental origins. To accelerate the transition of RAAS-based interventions for prevention of hypertension and kidney disease, an extended comprehension of the RAAS implicated in renal programming is needed, as well as a greater focus on further clinical translation.