Effect of a nitric oxide releasing derivative of paracetamol in a rat model of endotoxaemia

A meta-analysis of effects of vitamin E supplementation alone and in combination with omega-3 or magnesium on polycystic ovary syndrome

Vitamin E supplementation might have favorable effects on risk factors of polycystic ovary syndrome (PCOS). This systematic review and meta-analysis aimed to summarize the effects of vitamin E supplementation or vitamin E in combination with omega-3 or magnesium on PCOS. PubMed, Scopus, ISI Web of Science, Cochrane, Embase electronic databases, and Google scholar were searched for all available articles up to September 2022. Randomized controlled trials (RCTs) that examined the effect of vitamin E supplementation or vitamin E in combination with omega-3 or magnesium on lipid and glycemic profiles, anthropometric measurements, biomarkers of inflammation and oxidative stress, hormonal profile, and hirsutism score in patients with PCOS were included. Ten RCTs (with 504 participants) fulfilled the eligible criteria. Vitamin E supplementation or vitamin E in combination with omega-3 or magnesium in comparison to placebo could significantly reduce serum levels of TG (weighted mean difference: - 18.27 mg/dL, 95% CI - 34.68 to - 1.87), VLDL (- 5.88 mg/dL, 95% CI - 8.08 to - 3.68), LDL-c (- 12.84 mg/dL, 95% CI - 22.15 to - 3.52), TC (- 16.30 mg/dL, 95% CI - 29.74 to - 2.86), TC/HDL-c ratio (- 0.52, 95% CI - 0.87 to - 0.18), hs-CRP (- 0.60 ng/mL, 95% CI - 0.77 to - 0.44), hirsutism score (- 0.33, 95% CI - 0.65 to - 0.02) and significantly increase nitric oxide levels (2.79 µmol/L, 95% CI 0.79-4.79). No significant effect was found on HDL-c, glycemic indices, hormonal profile, anthropometric measurements, and other biomarkers of inflammation or oxidative stress. This meta-analysis highlights the potential anti-hyperlipidemic, anti-oxidant, and anti-inflammatory properties of vitamin E supplementation alone or in combination with omega-3 or magnesium on PCOS patients.

Gasotransmitters and the immune system: Mode of action and novel therapeutic targets

Gasotransmitters are a group of gaseous molecules, with pleiotropic biological functions. These molecules include nitric oxide (NO), hydrogen sulfide (H₂S), and carbon monoxide (CO). Abnormal production and metabolism of these molecules have been observed in several pathological conditions. The understanding of the role of gasotransmitters in the immune system has grown significantly in the past years, and independent studies have shed light on the effect of exogenous and endogenous gasotransmitters on immune responses. Moreover, encouraging results come from the efficacy of NO-, CO- and H₂S -donors in preclinical animal models of autoimmune, acute and chronic inflammatory diseases. To date, data on the influence of gasotransmitters in immunity and immunopathology are often scattered and partial, and the scarcity of clinical trials using NO-, CO- and H₂S -donors, reveals that more effort is warranted. This review focuses on the role of gasotransmitters in the immune system and covers the evidences on the possible use of gasotransmitters for the treatment of inflammatory conditions.

Cholecystokinin inhibits inducible nitric oxide synthase expression by lipopolysaccharide-stimulated peritoneal macrophages

Cholecystokinin (CCK) was first described as a gastrointestinal hormone. However, apart from its gastrointestinal effects, studies have described that CCK also plays immunoregulatory roles. Taking in account the involvement of inducible nitric oxide synthase- (iNOS-) derived NO in the sepsis context, the present study was undertaken to investigate the role of CCK on iNOS expression in LPS-activated peritoneal macrophages. Our results revealed that CCK reduces NO production and attenuates the iNOS mRNA expression and protein formation. Furthermore, CCK inhibited the nuclear factor- (NF-) κB pathway reducing IκBα degradation and minor p65-dependent translocation to the nucleus. Moreover, CCK restored the intracellular cAMP content activating the protein kinase A (PKA) pathway, which resulted in a negative modulatory role on iNOS expression. In peritoneal macrophages, the CCK-1R expression, but not CCK-2R, was predominant and upregulated by LPS. The pharmacological studies confirmed that CCK-1R subtype is the major receptor responsible for the biological effects of CCK. These data suggest an anti-inflammatory role for the peptide CCK in modulating iNOS-derived NO synthesis, possibly controlling the macrophage activation through NF-κB, cAMP-PKA, and CCK-1R pathways. Based on these findings, CCK could be used as an adjuvant agent to modulate the inflammatory response and prevent systemic complications commonly found during sepsis.

Hydrogen sulfide and nitric oxide interactions in inflammation

Together with carbon monoxide (CO), nitric oxide (NO) and hydrogen sulfide (H2S) form a group of physiologically important gaseous transmitters, sometimes referred to as the "gaseous triumvirate". The three molecules share a wide range of physical and physiological properties: they are small gaseous molecules, able to freely penetrate cellular membranes; they are all produced endogenously in the body and they seem to exert similar biological functions. In the cardiovascular system, for example, they are all vasodilators, promote angiogenesis and protect tissues against damage (e.g. ischemia-reperfusion injury). In addition, they have complex roles in inflammation, with both pro- and anti-inflammatory effects reported. Researchers have focused their efforts in understanding and describing the roles of each of these molecules in different physiological systems, and in the past years attention has also been given to the gases interaction or "cross-talk". This review will focus on the role of NO and H2S in inflammation and will give an overview of the evidence collected so far suggesting the importance of their cross-talk in inflammatory processes.

Circulating microparticles from septic shock patients exert differential tissue expression of enzymes related to inflammation and oxidative stress

OBJECTIVE

Septic shock is characterized by hypotension and multiple organ failure after infection of microorganisms. Septic shock patients display high levels of circulating microparticles. These are small vesicles released from the plasma membrane of activated or apoptotic cells. Here, we have investigated the effects of in vivo injection of microparticles from nonseptic or septic subjects on protein expression in mouse tissues.

DESIGN

Prospective, controlled experiments.

SETTING

Animal basic science laboratory.

SUBJECTS

Male Swiss mice were randomly assigned to one of two groups: 11 animals injected with microparticles isolated from healthy subjects and 15 animals injected with microparticles isolated from septic patients.

INTERVENTIONS

Microparticles were extracted from whole blood of septic and nonseptic subjects and were intravenously injected in mice. After 24 hrs, mice were killed and heart, lungs, liver, and kidneys were isolated for Western blot assays. Organs were also used for direct measurements of nitric oxide and superoxide anion production by electron paramagnetic resonance.

MEASUREMENTS AND MAIN RESULTS

In heart and lungs, microparticles from septic shock patients increased the expression of endothelial and inducible nitric oxide synthases, cyclooxygenase-2, and nuclear factor-κB. However, extracellular superoxide dismutase was only increased in the heart. These effects were associated either with a greater oxidative or nitrative stress in heart and lungs, without affecting nitric oxide production. The liver exhibited an increase in oxidative stress linked to decreased endothelial nitric oxide synthase and manganese superoxide dismutase expression. However, cyclooxygenase-2 expression and IκBα phosphorylation were decreased. Septic microparticles did not change superoxide anion and nitric oxide productions in kidneys.

CONCLUSIONS

Results suggest that microparticles from septic shock patients exert pleiotropic and differential effects depending on target tissues with regard to the expression of proinflammatory proteins related with nitrative and oxidative stresses. Thus, microparticles might participate in organ dysfunction observed in septic shock patients.

Interaction of a specific population of human embryonic stem cell-derived progenitor cells with CD11b+ cells ameliorates sepsis-induced lung inflammatory injury

Human embryonic stem cells differentiated under mesoderm-inducing conditions have important therapeutic properties in sepsis-induced lung injury in mice. Single cell suspensions obtained from day 7 human embryoid bodies (d7EBs) injected i.v. 1 hour after cecal ligation and puncture significantly reduced lung inflammation and edema as well as production of tumor necrosis factor-α and interferon-γ in lungs compared with controls, whereas interleukin-10 production remained elevated. d7EB cell transplantation also reduced mortality to 50% from 90% in the control group. The protection was ascribed to d7EB cell interaction with lung resident CD11b+ cells, and was correlated with the ability of d7EB cells to reduce it also reduced production of proinflammatory cytokines by CD11+ cells, and to endothelial NO synthase–derived NO by d7EB cells, leading to inhibition of inducible macrophage-type NO synthase activation in CD11b+ cells. The protective progenitor cells were positive for the endothelial and hematopoietic lineage marker angiotensin converting enzyme (ACE). Only the ACE+ fraction modulated the proinflammatory profile of CD11b+ cells and reduced mortality in septic mice. In contrast to the nonprotective ACE-cell fraction, the ACE+ cell fraction also produced NO. These findings suggest that an ACE+ subset of human embryonic stem cell–derived progenitor cells has a highly specialized anti-inflammatory function that ameliorates sepsis-induced lung inflammation and reduces mortality.

Actions and interactions of nitric oxide, carbon monoxide and hydrogen sulphide in the cardiovascular system and in inflammation--a tale of three gases!

Nitric oxide (NO), carbon monoxide (CO) and hydrogen sulphide (H(2)S) together make up a family of biologically active gases (the so-called 'gaseous triumvirate') with an increasingly well defined range of physiological effects plus roles to play in a number of disease states. Over the years, most researchers have concentrated their attention on understanding the part played by a single gas in one or more body systems. It is becoming more clear that all three gases are synthesised naturally in the body, often by the same cells within the same organs, and that all three gases exert essentially similar biological effects albeit via different mechanisms. Within the cardiovascular system, for example, all are vasodilators, promote angiogenesis and vascular remodelling and are protective towards tissue damage in for example, ischaemia-reperfusion injury in the heart. Similarly, all exhibit complex effects in inflammation with both pro- and anti-inflammatory effects recognised. It seems likely that cell function is controlled not by the activity of single gases working in isolation but by the concerted activity of all three of these gases working together.

Nitric oxide donors in sepsis: a systematic review of clinical and in vivo preclinical data

An abundant literature in the field of sepsis focuses on the role of NO. Inhibiting NO synthesis corrects certain hemodynamic parameters of septic shock but failed to improve outcome in patients. Conversely, administration of NO donors lowers blood pressure but restores microcirculatory flow in patients with sepsis. We undertook a systematic review of the literature to comprehensively summarize the results of studies exploring the effects of systemic NO donors in sepsis. We included both clinical and preclinical data. We described the details surrounding NO donor administration, and the results obtained in each study were regrouped in broad categories. In the case of animal research, we limited our data collection to in vivo protocols and described the sepsis model. Finally, we critically appraised all the studies included in the review. Overall, the reviewed publications aimed for physiopathological description rather than clinical relevance and did not meet the required criteria for extrapolation to clinical practice. With this reserve, NO donors usually improved the outcomes measured (e.g., mortality, pulmonary hypertension, tissue/organ perfusion, etc.) but also lowered blood pressure. We conclude that our findings warrant further animal experimentation designed to maximize clinical relevance.

Nitroparacetamol (NCX-701) and pain: first in a series of novel analgesics

The combination of numerous classic drugs with nitric oxide donors has led to the development of new compounds with promising therapeutic activities in a great variety of situations, including cardiovascular and respiratory systems, ocular pressure, inflammation, and pain. One of the first compounds developed was NCX-701 or nitroparacetamol, resulting from the combination of paracetamol, a classic and popular analgesic used in a great number of over-the-counter medications because of its antipyretic and analgesic properties, and a nitrooxybutyroyl moiety, which releases nitric oxide at a low but steady level. Although paracetamol is devoid of most of the gastrointestinal toxicity associated with aspirin-like drugs, this type of compounds was first designed to take advantage of the cytoprotective properties of nitric oxide when released at low concentrations. However, the combination of these molecules also resulted in an unexpected enhancement of the analgesic activity of paracetamol. In fact, NCX-701 has been shown to be effective in acute nociception as well as in neuropathic pain, situations in which paracetamol and other COX inhibitors are devoid of any effect. In addition, NCX-701 is more potent and, in some circumstances, more effective than its parent compound in different models of inflammatory pain. Furthermore, whereas paracetamol lacks any effective antiinflammatory action, NCX-701 might reduce inflammation. All these results taken together imply that the mechanism of action of NCX-701 is different from that of paracetamol, although it is not yet established for either molecule. NCX-701 appears to be a promising compound in the treatment of different types of pain, with a likely better profile of side effects than its parent molecule, paracetamol. Although recent clinical trials provided data consistent with the preclinical profile of NCX-701, further studies are needed to support its clinical use.

Recent developments in nitric oxide donor drugs

During the 1980s, the free radical, nitric oxide (NO), was discovered to be a crucial signalling molecule, with wide-ranging functions in the cardiovascular, nervous and immune systems. Aside from providing a credible explanation for the actions of organic nitrates and sodium nitroprusside that have long been used in the treatment of angina and hypertensive crises respectively, the discovery generated great hopes for new NO-based treatments for a wide variety of ailments. Decades later, however, we are still awaiting novel licensed agents in this arena, despite an enormous research effort to this end. This review explores some of the most promising recent advances in NO donor drug development and addresses the challenges associated with NO as a therapeutic agent.