Nitric oxide protects intestinal mucosal barrier function and prevents acute graft rejection after intestinal transplantation: A mini-review.

Intestinal transplantation is a complex technical procedure that provides patients suffering from end-stage intestinal failure an opportunity to enjoy improved quality of life, nutrition and survival. Compared to other types of organ transplants, it is a relatively new advancement in the field of organ transplantation. Nevertheless, great advances have been made over the past few decades to the present era, including the use of ischemic preconditioning, gene therapy, and addition of pharmacological supplements to preservation solutions. However, despite these strides, intestinal transplantation is still a challenging endeavor due to several factors. Notable among them is ischemia-reperfusion injury (IRI), which results in loss of cellular integrity and mucosal barrier function. In addition, IRI causes graft failure, delayed graft function, and decreased graft and recipient survival. This has necessitated the search for novel therapeutic avenues and improved transplantation protocols to prevent or attenuate intestinal IRI. Among the many candidate agents that are being investigated to combat IRI and its associated complications, nitric oxide (NO). NO is an endogenously produced gaseous signaling molecule with several therapeutic properties. The purpose of this mini-review is to discuss IRI and its related complications in intestinal transplantation, and NO as an emerging pharmacological tool against this challenging pathological condition. i.

Nitric oxide donor increases umbilical vein blood flow and fetal oxygenation in fetal growth restriction. A pilot study.

INTRODUCTION: To evaluate the maternal and fetal hemodynamic effects of treatment with a nitric oxide donor and oral fluid in pregnancies complicated by fetal growth restriction. METHODS: 30 normotensive participants with early fetal growth restriction were enrolled. 15 participants were treated until delivery with transdermal glyceryl trinitrate and oral fluid intake (Treated group), and 15 comprised the untreated group. All women underwent non-invasive assessment of fetal and maternal hemodynamics and repeat evaluation 2 weeks later. RESULTS: In the treated group, maternal hemodynamics improved significantly after two weeks of therapy compared to untreated participants. Fetal hemodynamics in the treated group showed an increase in umbilical vein diameter by 18.87 % (p < 0.01), in umbilical vein blood flow by 48.16 % (p < 0.01) and in umbilical vein blood flow corrected for estimated fetal weight by 30.03 % (p < 0.01). In the untreated group, the characteristics of the umbilical vein were unchanged compared to baseline. At the same time, the cerebro-placental ratio increased in the treated group, while it was reduced in the untreated group, compared to baseline values. The treated group showed a higher birthweight centile (p = 0.03) and a lower preeclampsia rate (p = 0.04) compared to the untreated group. DISCUSSION: The combined therapeutic approach with nitric oxide donor and oral fluid intake in fetal growth restriction improves maternal hemodynamics, which becomes more hyperdynamic (volume-dominant). At the same time, in the fetal circuit, umbilical vein flow increased and fetal brain sparing improved. Although a modest sample size, there was less preeclampsia and a higher birthweight suggesting beneficial maternal and fetal characteristics of treatment.

The study on synthesis and vitro hypolipidemic activity of novel berberine derivatives nitric oxide donors.

Berberine was used as the lead compound in the present study to design and synthesize novel berberine derivatives by splicing bromine bridges of different berberine carbon chain lengths coupled nitric oxide donors, and their lipid lowering activities were assessed in a variety of ways. This experiment synthesized 17 new berberine nitric oxide donor derivatives. Compared with berberine hydrochloride, most of the compounds exhibited certain glycerate inhibitory activity, and compounds 6a, 6b, 6d, 12b and 12d showed higher inhibitory activity than berberine, with 6a, 6b and 6d having significant inhibitory activity. In addition, compound 6a linked to furazolidone nitric oxide donor showed better NO release in experiments; In further mechanistic studies, we screened and got two proteins, PCSK9 and ACLY, and docked two proteins with 17 compounds, and found that most of the compounds bound better with ATP citrate lyase (ACLY), among which there may be a strong interaction between compound 6a and ACLY, and the interaction force was better than the target drug Bempedoic Acid, which meaning that 6a may exert hypolipidemic effects by inhibiting ACLY; moreover, we also found that 6a may had the better performance in gastrointestinal absorption, blood-brain barrier permeability, Egan, Muegge class drug principle model calculation and bioavailability.

Overview of the effects and mechanisms of NO and its donors on biofilms.

Microbial biofilm is undoubtedly a challenging problem in the food industry. It is closely associated with human health and life, being difficult to remove and antibiotic resistance. Therefore, an alternate method to solve these problems is needed. Nitric oxide (NO) as an antimicrobial agent, has shown great potential to disrupt biofilms. However, the extremely short half-life of NO in vivo (2 s) has facilitated the development of relatively more stable NO donors. Recent studies reported that NO could permeate biofilms, causing damage to cellular biomacromolecules, inducing biofilm dispersion by quorum sensing (QS) pathway and reducing intracellular bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) levels, and significantly improving the bactericidal effect without drug resistance. In this review, biofilm hazards and formation processes are presented, and the characteristics and inhibitory effects of NO donors are carefully discussed, with an emphasis on the possible mechanisms of NO resistance to biofilms and some advanced approaches concerning the remediation of NO donor deficiencies. Moreover, the future perspectives, challenges, and limitations of NO donors were summarized comprehensively. On the whole, this review aims to provide the application prospects of NO and its donors in the food industry and to make reliable choices based on these available research results.

Review on nitric oxide at the forefront of rapid systemic signaling in mitigation of salinity stress in plants: Crosstalk with calcium and hydrogen peroxide.

Soil salinity is a global issue that limits plant growth in agricultural fields and contributes to food crisis. Salt stressors impede plant's ionic, osmotic, and oxidative balance, as well as a variety of physiological functions. Exposure to salinity stress manifest considerable ROS clustering, entailing modification in performance of various organelles. To deal with salinity, plants use a variety of coping strategies, such as osmoregulation, ion-homeostasis, increased antioxidant synthesis, and so on. Nitric oxide (NO) is a pivotal signalling molecule that helps facilitate salt stress-induced physiological plant responses. A variety of evidences point to NO being produced under similar stress conditions and with similar kinetics as hydrogen peroxide (H2O2). The interplay between H2O2 and NO has important functional implications for modulating plant transduction processes. Besides, NO and calcium (Ca2+)-dependent pathways also have some connection in salt stress response mechanisms. Extensive crosstalk between NO and Ca2+ signalling pathways is investigated, and it suggests that almost every type of Ca2+ channel is under the tight control of NO, and NO acts as a Ca2+ mobilising compound and aids in signal reliance. The review provides insights into understanding recent advances regarding NO's, Ca2+ and H2O2 role in salt stress reduction with entwine signaling mechanisms.

Protective role of nitric oxide donors on endothelium in ischemia-reperfusion injury: a meta-analysis of randomized controlled trials.

BACKGROUND: Decreased bioavailability of nitric oxide (NO) under hypoxic conditions can lead to endothelial dysfunction. NO supplementation may protect endothelial function in ischemia-reperfusion (IR) injury. Therefore, a meta-analysis of randomized controlled trials (RCTs) was performed to verify the protective effect of NO donors on endothelium in IR injury. METHODS: Medline, Embase, Cochrane Library, and Web of Science databases were searched from inception to April 1, 2023. The specific inclusion criteria were as follows: (1) RCTs; (2) trials comparing NO donors with placebo control groups; and (3) trials reporting the effects of these interventions on vascular endothelial functional outcomes in IR injury. Random-effects models were used to assess pooled effect sizes, which were expressed as standardized mean differences (SMD). RESULTS: Seven studies satisfied the inclusion criteria and consisted of a total of 149 participants. NO donors were protective of endothelial function in IR injury (SMD: - 1.60; 95% confidence interval [CI]: - 2.33, - 0.88, P < 0.0001; heterogeneity [I2 = 66%, P = 0.001]). Results of the subgroup analysis showed the following: absence of protective effect of NO donor use following ischemia on endothelial function in IR injury - 1.78 (95% CI: - 2.50, - 1.07) and loss of protective effect on endothelial function after prolonged NO donor use - 0.89 (95% CI: - 2.06, 0.28). CONCLUSION: The short-period use of NO donors before the onset of ischemia can protect endothelial function in IR injury.

Synthesis and Evaluation of Novel Nitric Oxide-Donating Ligustrazine Derivatives as Potent Antiplatelet Aggregation Agents.

Antiplatelet aggregation agents have demonstrated clinical benefits in the treatment of ischemic stroke. In our study, a series of novel nitric oxide (NO)-donating ligustrazine derivatives were designed and synthesized as antiplatelet aggregation agents. They were evaluated for the inhibitory effect on 5'-diphosphate (ADP)-induced and arachidonic acid (AA)-induced platelet aggregation in vitro. The results showed that compound 15d displayed the best activity in both ADP-induced and AA-induced assays, and compound 14a also showed quite better activity than ligustrazine. The preliminary structure-activity relationships of these novel NO-donating ligustrazine derivatives were discussed. Moreover, these compounds were docked with the thromboxane A2 receptor to study the structure-activity relationships. These results suggested that the novel NO-donating ligustrazine derivatives 14a and 15d deserve further study as potent antiplatelet aggregation agents.

Beneficial Effects of Dinitrosyl Iron Complexes on Wound Healing Compared to Commercial Nitric Oxide Plasma Generator.

Nitric oxide (NO) is a gaseous molecule which plays a key role in wound healing. Previously, we identified the optimal conditions for wound healing strategies using NO donors and an air plasma generator. The aim of this study was to compare the wound healing effects of binuclear dinitrosyl iron complexes with glutathione (B-DNIC-GSH) and NO-containing gas flow (NO-CGF) at their optimal NO doses (0.04 mmol for B-DNIC-GSH and 1.0 mmol for NO-CGF per 1 cm2) in a rat full-thickness wound model over a 3-week period. Excised wound tissues were studied by light and transmission electron microscopy and immunohistochemical, morphometrical and statistical methods. Both treatments had an identical stimulating impact on wound healing, which indicated a higher dosage effectiveness of B-DNIC-GSH compared to the NO-CGF. B-DNIC-GSH spray application reduced inflammation and promoted fibroblast proliferation, angiogenesis and the growth of granulation tissue during the first 4 days after injury. However, prolonged NO spray effects were mild compared to NO-CGF. Future studies should determine the optimal B-DNIC-GSH solution course for a more effective wound healing stimulation.

DMF-Activated Nrf2 Ameliorates Palmitic Acid Toxicity While Potentiates Ferroptosis Mediated Cell Death: Protective Role of the NO-Donor S-Nitroso-N-Acetylcysteine.

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease that can develop into an aggressive form called nonalcoholic steatohepatitis (NASH), which ultimately progresses to cirrhosis, hepatocellular carcinoma (HCC), and end-stage liver failure. Currently, the deterioration of NAFLD is attributed to specific lipid toxicity which could be due to lipotoxicity and/or ferroptosis. In the current study, we evaluated the involvement of the nuclear factor erythroid 2 (NFE2)-related factor 2 (Nrf-2), which is a main activator of phase II metabolism in the two types of lipid-induced toxicity in hepatocytes, lipotoxicity by saturated fatty acids, and in ferroptosis, and the effect of NO donor treatment. AML12 cells were exposed to 600 µM palmitic acid to induce lipotoxicity or treated with 20 µM erastin or 5 µM RSL3 for ferroptosis. In SFA-lipotoxicity, pretreatment with the Nrf2 activator dimethyl fumarate (DMF) managed to ameliorate the cells and the oxidative stress level while aggravating ferroptosis due to emptying the thiol pool. On the other hand, the nitric oxide (NO)-donor, S-nitroso-N-acetylcysteine (NAC-SNO) proved to be effective in the prevention of hepatocytes ferroptosis.

New Nitric Oxide-Releasing Compounds as Promising Anti-Bladder Cancer Drugs.

Bladder cancer is a worldwide problem and improved therapies are urgently needed. In the search for newer strong antitumor compounds, herein, we present the study of three nitric oxide-releasing compounds and evaluate them as possible therapies for this malignancy. Bladder cancer cell lines T24 and 253J were used to evaluate the antiproliferative, antimigratory, and genotoxic effects of compounds. Moreover, we determined the NF-κB pathway inhibition, and finally, the survivin downregulation exerted by our molecules. The results revealed that compounds 1 and 3 exerted a high antiproliferative activity against bladder cancer cells through DNA damage and survivin downregulation. In addition, compound 3 reduced bladder cancer cell migration. We found that nitric oxide donors are promising molecules for the development of a new therapeutic targeting the underlying mechanisms of tumorigenesis and progression of bladder cancer.

Vascular Effects of the Fetal Hemoglobin Inducer Agent 3-(1,3-Dioxoisoindolin-2-yl) Benzyl Nitrate.

Vascular endothelium is a protective layer of cells lining the lumen of blood vessels that plays important roles by releasing factors responsible for controlling the vascular tone, regulating the expression of pro-inflammatory cytokines, and expressing adhesion molecules involved in vascular hemostasis. Imbalance of vascular properties leads to endothelial dysfunction (ED) and cardiovascular damage. Some diseases, such as sickle cell anemia, are characterized by ED with reduction in the levels of nitric oxide (NO). Previously, we have shown that the fetal hemoglobin inducer agent 3-(1,3-dioxoisoindolin-2-yl) benzyl nitrate (Lapdesf-4c) could act as NO donor, inhibiting platelet aggregation and reducing the inflammation associated with SCA. However, the vascular effect of this compound was not yet studied. Herein, we evaluated the effects of Lapdesf-4c in vascular reactivity experiments using aortic rings from male Wistar rats (300 g/90 days). We have found that Lapdesf-4c induced vasodilation in the presence (E+) or absence of endothelium (E-) with an average of EMax values of 101.8 ± 3.33% and 111.8 ± 3.21%. The mechanism of action was studied using 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ), L-NG-nitroarginine methyl ester (L-NAME), and hydroxocobalamin. The EMax values for those pathways were hydroxocobalamin (30.6 ± 2.21%), ODQ (4.75 ± 0.51%), and L-NAME (109 ± 3.65), suggesting that Lapdesf-4c exhibits NO-dependent mechanisms. Lapdesf-4c was able to prevent angiotensin-induced ED after incubation of aorta rings for 1 h. We found based on the concentration-effect curve using acetylcholine (ACh) that pEC50 values for the control, Ang II, and combination of (Ang II + Lapdesf-4c) were 6.73, 6.46, and 7.15, respectively. In conclusion, Lapdesf-4c has emerged as a new drug candidate that can promote vasodilation and act as a protective agent against ED, being useful to prevent vascular damage.

Use of Nitric Oxide Donor-Loaded Microbubble Destruction by Ultrasound in Thrombus Treatment.

In the presence of a vascular thrombus, the recovery of blood flow and vascular recanalization are very important to prevent tissue damage. An alternative procedure to thrombolysis is required for patients who are unable to receive surgery or thrombolytic drugs due to other physical conditions. Recently, the performance of thrombolysis combined with microbubbles has become an attractive and effective therapeutic procedure. Indeed, in a recent study, we demonstrated that, upon exposure to ultrasound, liposomes loaded with nitric oxide release agonists conjugated to microbubbles; therefore, there is potential to release the agonist in a controlled manner into specific tissues. This means that the effect of the agonist is potentiated, decreasing interactions with other tissues, and reducing the dose required to induce nitric-oxide-dependent vasodilation. In the present study, we hypothesized that a liposome microbubble delivery system can be used as a hydrophilic agonist carrier for the nitric oxide donor spermine NONOate, to elicit femoral vasodilation and clot degradation. Therefore, we used spermine-NONOate-loaded microbubbles to evaluate the effect of ultrasound-mediated microbubble disruption (UMMD) on thromboembolic femoral artery recanalization. We prepared spermine NONOate-loaded microbubbles and tested their effect on ex vivo preparations, hypothesizing that ultrasound-induced microbubble disruption is associated with the vasorelaxation of aortic rings. Thrombolysis was demonstrated in aorta blood-flow recovery after disruption by spermine NONOate-loaded microbubbles via ultrasound application in the region where the thrombus is located. Our study provides an option for the clinical translation of NO donors to therapeutic applications.

Novel Type of Tetranitrosyl Iron Salt: Synthesis, Structure and Antibacterial Activity of Complex [FeL'2(NO)2][FeL'L"(NO)2] with L'-thiobenzamide and L"-thiosulfate.

In this work a new donor of nitric oxide (NO) with antibacterial properties, namely nitrosyl iron complex of [Fe(C6H5C-SNH2)2(NO)2][Fe(C6H5C-SNH2)(S2O3)(NO)2] composition (complex I), has been synthesized and studied. Complex I was produced by the reduction of the aqueous solution of [Fe2(S2O3)2(NO)2]2- dianion by the thiosulfate, with the further treatment of the mixture by the acidified alcohol solution of thiobenzamide. Based on the structural study of I (X-ray analysis, quantum chemical calculations by NBO and QTAIM methods in the frame of DFT), the data were obtained on the presence of the NO…NO interactions, which stabilize the DNIC dimer in the solid phase. The conformation properties, electronic structure and free energies of complex I hydration were studied using B3LYP functional and the set of 6-31 + G(d,p) basis functions. The effect of an aquatic surrounding was taken into account in the frame of a polarized continuous model (PCM). The NO-donating activity of complex I was studied by the amperometry method using an "amiNO-700" sensor electrode of the "inNO Nitric Oxide Measuring System". The antibacterial activity of I was studied on gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. Cytotoxicity was studied using Vero cells. Complex I was found to exhibit antibacterial activity comparable to that of antibiotics, and moderate toxicity to Vero cells.

Effect of topical nitric oxide donors 0.03% nitroglycerin and 0.1% hydralazine on intraocular pressure in healthy canine eyes.

OBJECTIVE: To investigate the potential intraocular pressure (IOP)-lowering effects of nitric oxide (NO)-donating compounds in healthy canine eyes METHODS: A total of 79 dogs were divided into 3 groups in a masked, controlled and randomised study. Group N (n = 26) was administered 0.03% nitroglycerin in one eye and vehicle-control in the other, Group H (n = 26) was administered 0.1% hydralazine in one eye and vehicle-control in the other, while Group C (n = 27) received vehicle-control in both eyes (control group). Following eye drop administration, IOP was measured in both eyes at selected times (10-250 min), along with monitoring of heart rate and signs of ocular discomfort. Data was analysed with repeated measures mixed model and one-way ANOVA RESULTS: IOP was significantly reduced over the 4-h period with 0.03% nitroglycerin (p < 0.0001) but not 0.1% hydralazine (p = 0.520) when compared to contralateral vehicle-controlled eyes. IOP was reduced by up to 12% with 0.03% nitroglycerin from 10 to 70 min post-treatment; however, differences in IOP at individual time points were not statistically significant for either drug (p ≥ 0.133) as compared to contralateral vehicle-control eyes. No treatment group significantly affected heart rate (compared to Group C), and both treatment groups appeared well tolerated CONCLUSIONS: Both compounds were well-tolerated in healthy dogs. Nitroglycerin mildly reduced IOP in canine eyes, and further investigations are warranted in healthy and diseased states (e.g. glaucoma, ocular hypertension).

The NO/cGMP/PKG pathway in platelets: The therapeutic potential of PDE5 inhibitors in platelet disorders.

Platelets are the "guardians" of the blood circulatory system. At sites of vessel injury, they ensure hemostasis and promote immunity and vessel repair. However, their uncontrolled activation is one of the main drivers of thrombosis. To keep circulating platelets in a quiescent state, the endothelium releases platelet antagonists including nitric oxide (NO) that acts by stimulating the intracellular receptor guanylyl cyclase (GC). The latter produces the second messenger cyclic guanosine-3',5'-monophosphate (cGMP) that inhibits platelet activation by stimulating protein kinase G, which phosphorylates hundreds of intracellular targets. Intracellular cGMP pools are tightly regulated by a fine balance between GC and phosphodiesterases (PDEs) that are responsible for the hydrolysis of cyclic nucleotides. Phosphodiesterase type 5 (PDE5) is a cGMP-specific PDE, broadly expressed in most tissues in humans and rodents. In clinical practice, PDE5 inhibitors (PDE5i) are used as first-line therapy for erectile dysfunction, pulmonary artery hypertension, and lower urinary tract symptoms. However, several studies have shown that PDE5i may ameliorate the outcome of various other conditions, like heart failure and stroke. Interestingly, NO donors and cGMP analogs increase the capacity of anti-platelet drugs targeting the purinergic receptor type Y, subtype 12 (P2Y12) receptor to block platelet aggregation, and preclinical studies have shown that PDE5i inhibits platelet functions. This review summarizes the molecular mechanisms underlying the effect of PDE5i on platelet activation and aggregation focusing on the therapeutic potential of PDE5i in platelet disorders, and the outcomes of a combined therapy with PDE5i and NO donors to inhibit platelet activation.

Design, synthesis and biological evaluation of novel nitric oxide donors with antioxidative activity.

Reactive oxygen species (ROS) are the primary cause of organic nitrate drug tolerance and endothelial dysfunction. In order to scavenge the ROS and maintain the therapeutic effect of nitrates, we designed and synthesized ten new types of dual-acting nitrate molecules by combining NIT-type nitroxides and 5-ISMN. These included two types of novel epimeric nitroxide-nitrate conjugates (15(S) and 15(R)), which had pharmacophore connections. We also synthesized 8 NIT radicals without 5-ISMN in order to compare the activities of these novel nitric oxide donors. Several dual-acting nitroxide-based nitrate conjugates showed the ability to release NO and cause anti-oxidant effects in human umbilical vein endothelial cells. Among these conjugates, 15(S) showed the most prominent pro-vasodilative effect. In angiotensin II infusion-induced hypertensive mice, 15(S) treatment for 4 weeks decreased both the systolic and diastolic blood pressures and ameliorated the vascular endothelial and smooth muscle functions of isolated thoracic aortas. In addition, the vascular structure of the mice was restored and their vascular oxidative stress was decreased. The results suggest that these novel nitric oxide donors can be used as potential drugs in the treatment of vascular diseases. Therefore, the strategy of using a combination of antioxidants and NO-donors can be a promising way to develop novel organic nitrate drugs for future use in combating disease.

The Antiplatelet Action of S-Nitroso Human Serum Albumin in Whole Blood.

Nitric oxide donors (NO-donors) have been shown to have therapeutic potential (e.g., ischemia/reperfusion injury). However, due to their release rate/antiplatelet properties, they may cause bleeding in patients. We therefore studied the antiplatelet effects of the two different NO-donors, i.e., S-NO-Human Serum Albumin (S-NO-HSA) and Diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA-NONOate) in whole blood (WB) samples. WB samples were spiked with S-NO-HSA or DEA-NONOate (100 µmol/L or 200 µmol/L), and the NO release rate (nitrite/nitrate levels via HPLC) and antiplatelet efficacy (impedance aggregometry, platelet function analyzer, Cone-and-platelet analyzer, thrombelastometry) were assessed. S-NO-HSA had a significantly lower NO release compared to equimolar concentrations of DEA-NONOate. Virtually no antiplatelet action of S-NO-HSA was observed in WB samples, whereas DEA-NONOate significantly attenuated platelet function in WB. Impedance aggregometry measurements revealed that Amplitudes (slope: -0.04022 ± 0.01045 ohm/µmol/L, p = 0.008) and Lag times (slope: 0.6389 ± 0.2075 s/µmol/L, p = 0.0051) were dose-dependently decreased and prolonged by DEA-NONOate. Closure times (Cone-and-platelet analyzer) were dose-dependently prolonged (slope: 0.3738 ± 0.1403 s/µmol/L, p = 0.0174 with collagen/ADP coating; slope: -0.5340 ± 0.1473 s/µmol/L, p = 0.0019 with collagen/epinephrine coating) by DEA-NONOate. These results in WB further support the pharmacological potential of S-NO-HSA as an NO-donor due to its ability to presumably prevent bleeding events even at high concentrations up to 200 µmol/L.

Pathways involved in the human vascular Tetrabromobisphenol A response: Calcium and potassium channels and nitric oxide donors.

Tetrabromobisphenol A (TBBPA) is a flame retardant that can contaminate the environment and human being, acting as an endocrine disruptor. Several studies propose a correlation between TBBPA exposure and adverse health outcomes, however, at vascular level TBBPA effects are still poorly understood. Thus, considering that the vascular tonus is regulated by vasoactive substances (serotonin and histamine) which are involved in some pathological processes, this work aimed to analyse the direct effects and the 24 h exposure of TBBPA on the human umbilical artery (HUA) and to investigate its signalling pathway. Using organ bath technique, endothelium-denuded HUA rings were contracted with serotonin (5-HT, 1 µM), histamine (His, 10 µM) and potassium chloride (KCl, 60 mM), and the exposure (0-24 h) of different concentrations of TBBPA (1, 10 and 50 µM) were evaluated. Besides, the vascular mode of action of TBBPA was studied through the analysis of cyclic guanosine monophosphate and calcium channels activity, pathways involved in relaxation and contraction of HUA, respectively. Our results demonstrated that the direct effects of TBBPA induce a vasorelaxation of HUA. The maximum relaxant effect was observed at 100 µM of TBBPA with 63.74%, 64.24% and 30.05%, for 5-HT-, His- or KCl-contracted arteries respectively. The 24 h TBBPA exposure altered the vasorelaxant response pattern of sodium nitroprusside and nifedipine. This effect is due to the involvement of TBBPA with the NO/sGC/cGMP/PKG pathway and the interference in calcium influx. Furthermore, using the real-time quantitative polymerase chain reaction, TBBPA clearly modulates L-type calcium and large-conductance Ca2+ 1.1 α- and ß1 -subunit channels, and soluble guanylyl cyclase and protein Kinase G. So, at vascular level TBBPA induces changes in HUA after TBBPA exposure.

Recent Developments in Nitric Oxide Donors and Delivery for Antimicrobial and Anti-Biofilm Applications.

The use of nitric oxide (NO) is emerging as a promising, novel approach for the treatment of antibiotic resistant bacteria and biofilm infections. Depending on the concentration, NO can induce biofilm dispersal, increase bacteria susceptibility to antibiotic treatment, and induce cell damage or cell death via the formation of reactive oxygen or reactive nitrogen species. The use of NO is, however, limited by its reactivity, which can affect NO delivery to its target site and result in off-target effects. To overcome these issues, and enable spatial or temporal control over NO release, various strategies for the design of NO-releasing materials, including the incorporation of photo-activable, charge-switchable, or bacteria-targeting groups, have been developed. Other strategies have focused on increased NO storage and delivery by encapsulation or conjugation of NO donors within a single polymeric framework. This review compiles recent developments in NO drugs and NO-releasing materials designed for applications in antimicrobial or anti-biofilm treatment and discusses limitations and variability in biological responses in response to the use of NO for bacterial eradiation.

Tratamiento farmacológico en la restricción del crecimiento fetal: revisión de la bibliografía / Pharmacological management for fetal growth restriction: literature review

Resumen OBJETIVO: Explorar las diferentes estrategias de tratamiento farmacológico de la restricción del crecimiento fetal propuestas a lo largo del tiempo. METODOLOGÍA: Revisión cuasi-sistemática de la evidencia científica histórica disponible acerca del tratamiento médico descrito para la atención de mujeres embarazadas con restricción del crecimiento fetal. RESULTADOS: Entre los tratamientos médicos descritos para tratar la restricción del crecimiento fetal, los donadores de óxido nítrico, las estatinas y la aspirina asociada con omega 3, han tenido desenlaces no consistentes en estudios con limitado tamaño de muestra. Por lo que se refiere a los inhibidores de la 5-fosfodiesterasa, el sildenafilo no se ha asociado con un aumento de la velocidad de crecimiento fetal pero sí con alarmas respecto de su seguridad debidas al incremento de los casos de hipertensión pulmonar fetal y mortalidad perinatal. Por su parte, el tadalafilo ha mostrado desenlaces iniciales favorables y se esperan estudios con mayor tamaño de muestra que permitan emitir recomendaciones claras con respecto a su indicación. También se esperan los desenlaces de estudios clínicos en curso, para definir la indicación de la heparina de bajo peso molecular en este escenario en virtud de sus prometedores resultados iniciales. Los procedimientos más invasivos, como la inyección de factor de crecimiento endotelial vascular y la plasmaféresis, permanecen en estudio como propuestas terapéuticas por los resultados de estudios preclínicos y clínicos con pocos pacientes. CONCLUSIÓN: Por ahora, ninguna estrategia farmacológica propuesta ha conseguido generar recomendaciones fuertes para su indicación; sin embargo, se esperan nuevos estudios con alta calidad metodológica que generen evidencia científica lo suficientemente contundente para recomendar su indicación.

Abstract OBJECTIVE: To explore the different pharmacological treatment strategies for fetal growth restriction proposed over time. METHODOLOGY: Quasi-systematic review of the available historical scientific evidence on the medical treatment described for the care of pregnant women with fetal growth restriction. RESULTS: Among the medical treatments described to treat fetal growth restriction, nitric oxide donors, statins, and aspirin associated with omega-3 have had inconsistent outcomes in studies with limited sample size. As for 5-phosphodiesterase inhibitors, sildenafil has not been associated with an increase in fetal growth velocity, but there have been alarms regarding its safety due to the increase in cases of fetal pulmonary hypertension and perinatal mortality. On the other hand, tadalafil has shown favorable initial outcomes and studies with a larger sample size are awaited to issue clear recommendations regarding its indication. The results of ongoing clinical studies are also awaited to define the indication of low molecular weight heparin in this setting, given its promising initial results. More invasive procedures, such as vascular endothelial growth factor injection and plasmapheresis, remain under study as therapeutic proposals due to the results of preclinical and clinical studies with few patients. CONCLUSION: For now, no proposed pharmacological strategy has managed to generate strong recommendations for its indication; however, new studies with high methodological quality are expected to generate scientific evidence strong enough to recommend its indication.