Protective effects of N-acetylcysteine and beta-glucan pretreatment on oxidative stress in cecal ligation and puncture model of sepsis

Glucans: A Therapeutic Alternative for Sepsis Treatment

Sepsis treatment is a challenging condition due to its complexity, which involves host inflammatory responses to a severe and potentially fatal infection, associated with organ dysfunction. The aim of this study was to analyze the scientific literature on the immunomodulatory effects of glucans in a murine model of systemic infection induced by cecal ligation and puncture. This study comprises an integrative literature review based on systematic steps, with searches carried out in the PubMed, ScienceDirect, Scopus, Web of Science, and Embase databases. In most studies, the main type of glucan investigated was β-glucan, at 50 mg/kg, and a reduction of inflammatory responses was identified, minimizing the occurrence of tissue damage leading to increased animal survival. Based on the data obtained and discussed in this review, glucans represent a promising biotechnological alternative to modulate the immune response and could potentially be used in the clinical management of septic individuals.

Proposed mechanisms of action of herbal drugs and their biologically active constituents in the treatment of coughs: an overview

Various medicinal plants find their use in cough treatment, based on traditions and long-term experience. Pharmacological principles of their action, however, are much less known. Herbal drugs usually contain a mixture of potentially active compounds, which can manifest diverse effects. Expectorant or antitussive effects, which can be accompanied by others, such as anti-inflammatory or antibacterial, are probably the most important in the treatment of coughs. The aim of this review is to summarize the current state of knowledge of the effects of medicinal plants or their constituents on cough, based on reliable pharmacological studies. First, a comprehensive description of each effect is provided in order to explain the possible mechanism of action in detail. Next, the results related to individual plants and substances are summarized and critically discussed based on pharmacological in vivo and in vitro investigation.

The effect of N-acetyl-l-cysteine on inflammation after intraperitoneal mesh placement in a potentially contaminated environment: Experimental study in the rat

BACKGROUND

The use of prosthetic meshes in abdominal wall reconstruction is a well-established approach; however, in certain cases where a bowel resection coexists its application is disputed. Any underlying inflammatory process may augment adhesion formation which is a major postoperative complication. In this animal study, our aim was to investigate the effect of N-acetyl-l-cysteine (NAC) on adhesion formation and the expression of inflammatory markers when a mesh was used in a clean or a potentially contaminated environment.

METHODS

Sixty male Wistar rats were randomly and equally allocated in 3 groups: A, B and C. Animals in all groups underwent laparotomy, a prosthetic mesh was placed and chemoprophylaxis with ciprofloxacin was administered. In groups B and C an enterectomy was also performed. NAC was injected intraperitoneally in group C. Adhesion formation, IL-1a, IL-6, TNF-a and histological data including fibrosis, neutrophils' infiltration and neovascularization were assessed. Mesh samples were sent for cultivation.

RESULTS

Adhesion formation was significantly less and inflammation markers were also lower in group C compared to group B (p<0.05). Histological findings were significant for greater fibrosis, neutrophils' infiltration and neovascularization in group B compared to both group A and C. Regarding mesh cultures, more specimens were tested positive in group B (p <0.05). Outcomes between group A and C did not differ.

CONCLUSION

NAC effectively ameliorated adhesion formation and inflammation in a potentially septic environment where a prosthetic mesh was placed.

Nrf2-A Molecular Target for Sepsis Patients in Critical Care

The transcription factor NF-E2 p45-related factor 2 (Nrf2) is an established master regulator of the anti-oxidative and detoxifying cellular response. Thus, a role in inflammatory diseases associated with the generation of large amounts of reactive oxygen species (ROS) seems obvious. In line with this, data obtained in cell culture experiments and preclinical settings have shown that Nrf2 is important in regulating target genes that are necessary to ensure cellular redox balance. Additionally, Nrf2 is involved in the induction of phase II drug metabolizing enzymes, which are important both in degrading and converting drugs into active forms, and into putative carcinogens. Therefore, Nrf2 has also been implicated in tumorigenesis. This must be kept in mind when new therapy approaches are planned for the treatment of sepsis. Therefore, this review highlights the function of Nrf2 in sepsis with a special focus on the translation of rodent-based results into sepsis patients in the intensive care unit (ICU).

β-Glucan Metabolic and Immunomodulatory Properties and Potential for Clinical Application

β-glucans are complex polysaccharides that are found in several plants and foods, including mushrooms. β-glucans display an array of potentially therapeutic properties. β-glucans have metabolic and gastro-intestinal effects, modulating the gut microbiome, altering lipid and glucose metabolism, reducing cholesterol, leading to their investigation as potential therapies for metabolic syndrome, obesity and diet regulation, gastrointestinal conditions such as irritable bowel, and to reduce cardiovascular and diabetes risk. β-glucans also have immune-modulating effects, leading to their investigation as adjuvant agents for cancers (solid and haematological malignancies), for immune-mediated conditions (e.g., allergic rhinitis, respiratory infections), and to enhance wound healing. The therapeutic potential of β-glucans is evidenced by the fact that two glucan isolates were licensed as drugs in Japan as immune-adjuvant therapy for cancer in 1980. Significant challenges exist to further clinical testing and translation of β-glucans. The diverse range of conditions for which β-glucans are in clinical testing underlines the incomplete understanding of the diverse mechanisms of action of β-glucans, a key knowledge gap. Furthermore, important differences appear to exist in the effects of apparently similar β-glucan preparations, which may be due to differences in sources and extraction procedures, another poorly understood issue. This review will describe the biology, potential mechanisms of action and key therapeutic targets being investigated in clinical trials of β-glucans and identify and discuss the key challenges to successful translation of this intriguing potential therapeutic.

N-Acetylcysteine's Role in Sepsis and Potential Benefit in Patients With Microcirculatory Derangements

OBJECTIVE

To review the data surrounding the utility of N-acetylcysteine (NAC) in sepsis and identify areas needed for additional research.

DATA SOURCES

A review of articles describing the mechanisms of action and clinical use of NAC in sepsis.

SUMMARY OF REVIEW

Despite many advances in critical care medicine, still as many as 50% of patients with septic shock die. Treatments thus far have focused on resuscitation and restoration of macrocirculatory targets in the early phases of sepsis, with less focus on microcirculatory dysfunction. N-acetylcysteine, due to its anti-inflammatory and antioxidative properties, has been readily investigated in sepsis and has yielded largely incongruous and disappointing results. In addition to its known anti-inflammatory and antioxidative roles, one underappreciated property of NAC is its ability to vasodilate the microcirculation and improve locoregional blood flow. Some investigators have sought to capitalize on this mechanism with promising results, as evidenced by microcirculatory vasodilation, improvements in regional blood flow and oxygen delivery, and reductions in lactic acidosis, organ failure, and mortality.

CONCLUSION

In addition to its antioxidant and anti-inflammatory properties, N-acetylcysteine possesses vasodilatory properties that could benefit the microcirculation in sepsis. It is imperative that we investigate these properties to uncover NAC's full potential for benefit in sepsis.

Effects of β-glucan pretreatment on acetylsalicylic acid-induced gastric damage: An experimental study in rats

BACKGROUND

NSAIDs have been found to induce gastrointestinal tract damage. Recently, it has been suggested that this might be mediated by lipid peroxidation.

OBJECTIVE

The aim of this study was to assess the potential protective effects of β-glucan against acetylsalicylic acid (ASA-induced gastric damage by means of its antioxidant capacity in an experimental rat model.

METHODS

Thirty-two male Wistar albino rats (200-250 g) were randomized into 4 groups consisting of 8 rats each. The β-glucan group received 50 mg/kg β-glucan once a day for 10 days and 30 minutes before anesthesia. The ASA group received saline once a day for 10 days and 300 mg/kg (20 mg/mL) ASA as a single dose, 4 hours before anesthesia. The ASA+β-glucan group was administered 50 mg/kg β-glucan once a day for 10 days and 30 minutes before anesthesia. Additionally, 300 mg/kg (20 mg/mL) ASA was administered as a single dose, 4 hours before anesthesia. The control group received saline once a day for 10 days and 30 minutes before anesthesia. All medications were administered by intragastric gavage. The stomach from each rat was dissected and divided into 2 parts for histologic and biochemical analysis. Gastric tissue malondialdehyde (MDA), nitric oxide (NO) levels, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were determined for oxidative parameter analysis.

RESULTS

The gastroprotective and antioxidant effects of β-glucan appeared to attenuate the ASA-induced gastric tissue damage. Compared with the control group, MDA and NO levels and CAT and GSH-Px activities were significantly increased in the stomachs of ASA-treated rats (MDA, 4.12 [0.44] to 13.41 [1.05] μmol/L; NO, 8.04 [7.25-9.10] vs 30.35 [22.34-37.95] μmol/g protein; CAT, 0.050 [0.004] to 0.083 [0.003] k/g protein; GSH-Px, 0.57 [0.42-0.66] to 1.55 [1.19-1.76] U/L; all, P < 0.001), whereas SOD activity was significantly decreased in the same group (291 [29] to 124 [6] U/mL; P < 0.001). In the ASA+β-glucan group, MDA and NO levels and CAT and GSH-Px activities were found to be significantly lower, while SOD activity was found to be significantly higher, in comparison with the ASA-treated group (all, P < 0.001).

CONCLUSION

β-Glucan appeared to attenuate the gastric damage caused by ASA in these rats.

Protein carbonylation as a major hallmark of oxidative damage: update of analytical strategies

Protein carbonylation, one of the most harmful irreversible oxidative protein modifications, is considered as a major hallmark of oxidative stress-related disorders. Protein carbonyl measurements are often performed to assess the extent of oxidative stress in the context of cellular damage, aging and several age-related disorders. A wide variety of analytical techniques are available to detect and quantify protein-bound carbonyls generated by metal-catalyzed oxidation, lipid peroxidation or glycation/glycoxidation. Here we review current analytical approaches for protein carbonyl detection with a special focus on mass spectrometry-based techniques. The utility of several carbonyl-derivatization reagents, enrichment protocols and especially advanced mass spectrometry techniques are compared and discussed in detail. Furthermore, the mechanisms and biology of protein carbonylation are summarized based on recent high-throughput proteomics data.

Generating and reversing chronic wounds in diabetic mice by manipulating wound redox parameters

By 2025, more than 500 M people worldwide will suffer from diabetes; 125 M will develop foot ulcer(s) and 20 M will undergo an amputation, creating a major health problem. Understanding how these wounds become chronic will provide insights to reverse chronicity. We hypothesized that oxidative stress (OS) in wounds is a critical component for generation of chronicity. We used the db/db mouse model of impaired healing and inhibited, at time of injury, two major antioxidant enzymes, catalase and glutathione peroxidase, creating high OS in the wounds. This was necessary and sufficient to trigger wounds to become chronic. The wounds initially contained a polymicrobial community that with time selected for specific biofilm-forming bacteria. To reverse chronicity we treated the wounds with the antioxidants α-tocopherol and N-acetylcysteine and found that OS was highly reduced, biofilms had increased sensitivity to antibiotics, and granulation tissue was formed with proper collagen deposition and remodeling. We show for the first time generation of chronic wounds in which biofilm develops spontaneously, illustrating importance of early and continued redox imbalance coupled with the presence of biofilm in development of wound chronicity. This model will help decipher additional mechanisms and potentially better diagnosis of chronicity and treatment of human chronic wounds.

Immunostimulatory properties and antitumor activities of glucans (Review)

New foods and natural biological modulators have recently become of scientific interest in the investigation of the value of traditional medical therapeutics. Glucans have an important part in this renewed interest. These fungal wall components are claimed to be useful for various medical purposes and they are obtained from medicinal mushrooms commonly used in traditional Oriental medicine. The immunotherapeutic properties of fungi extracts have been reported, including the enhancement of anticancer immunity responses. These properties are principally related to the stimulation of cells of the innate immune system. The discovery of specific receptors for glucans on dendritic cells (dectin-1), as well as interactions with other receptors, mainly expressed by innate immune cells (e.g., Toll-like receptors, complement receptor-3), have raised new attention toward these products as suitable therapeutic agents. We briefly review the characteristics of the glucans from mycelial walls as modulators of the immunity and their possible use as antitumor treatments.

Effect of β-glucan originated from Aureobasidium pullulans on asthma induced by ovalbumin in mouse

The objective of this study is to detect the effect of beta-glucan derived from Aureobasidium pullulans SM-2001, a UV induced mutant of A. pullulans on the ovalbumin (OVA) induced allergic asthma. The test articles were orally administered to OVA-inducing asthmatic mice 4 days after sensitization for 13 days at 31.25, 62.5 or 125 mg/kg levels. Three days after the OVA sensitization, ten mice were selected per group based on body weight and were sacrificed three days after the OVA aerosol challenge. The changes on the body weight, lung weight, total leukocytes in peripheral blood and total cells in bronchoalveolar lavage fluid (BALF) were observed with changes on the lung histopathology and histomorphometry. The results were compared with dexamethasone (DEXA) 3 mg/kg intraperitoneally treated mice. The results showed increases of body weight after the OVA aerosol challenge, lung weight, total leukocytes and eosinophils in peripheral blood, total cell numbers, neutrophil and eosinophils in BALF were detected in the OVA control compared to sham control (non-OVA). However, these changes from asthmatic responses were significantly or dose-dependently decreased in the beta-glucan-dosing groups compared to those of the OVA control. Therefore, it is concluded that beta-glucan has favorable effects on asthmatic response induced by OVA. It was found that beta-glucan 125 mg/kg showed similar or slightly lower efficacy compared with DEXA 3 mg/kg.

Glutathione homeostasis and functions: potential targets for medical interventions

Glutathione (GSH) is a tripeptide, which has many biological roles including protection against reactive oxygen and nitrogen species. The primary goal of this paper is to characterize the principal mechanisms of the protective role of GSH against reactive species and electrophiles. The ancillary goals are to provide up-to-date knowledge of GSH biosynthesis, hydrolysis, and utilization; intracellular compartmentalization and interorgan transfer; elimination of endogenously produced toxicants; involvement in metal homeostasis; glutathione-related enzymes and their regulation; glutathionylation of sulfhydryls. Individual sections are devoted to the relationships between GSH homeostasis and pathologies as well as to developed research tools and pharmacological approaches to manipulating GSH levels. Special attention is paid to compounds mainly of a natural origin (phytochemicals) which affect GSH-related processes. The paper provides starting points for development of novel tools and provides a hypothesis for investigation of the physiology and biochemistry of glutathione with a focus on human and animal health.

Protective effects of beta glucan and gliclazide on brain tissue and sciatic nerve of diabetic rats induced by streptozosin

There have not been yet enough studies about effects of beta glucan and gliclazide on oxidative stress created by streptozotocin in the brain and sciatic nerve of diabetic rats. The aim of this paper was to investigate the antioxidant effects of gliclazide and beta glucan on oxidative stress and lipid peroxidation created by streptozotosin in brain and sciatic nerve. Total of 42 rats were divided into 6 groups including control, diabetic untreated (DM) (only STZ, diabetic), STZ (DM) + beta glucan, STZ (DM) + gliclazide, only beta glucan treated (no diabetic), and only gliclazide treated (no diabetic). The brain and sciatic nerve tissue samples were analyzed for malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), and paraoxonase (PON-1) levels. We found a significant increase in MDA, TOS, and OSI along with a reduction in TAS level, catalase, and PON-1 activities in brain and sciatic nerve of streptozotocin-induced diabetic rats. Also, this study shows that in terms of these parameters both gliclazide and beta glucan have a neuroprotective effect on the brain and sciatic nerve of the streptozotocin-induced diabetic rat. Our conclusion was that gliclazide and beta glucan have antioxidant effects on the brain and sciatic nerve of the streptozotocin-induced diabetic rat.

Hyperbaric oxygen and N-acetylcysteine treatment in L-arginine-induced acute pancreatitis in rats

BACKGROUND

This study was designed to evaluate the combined effects of hyperbaric oxygen (HBO) and N-acetylcysteine (NAC) on acute necrotizing pancreatitis in rats.

METHODS

Experiments were performed in 50 male Wistar rats, which were divided into five groups (N = 10 for each group). The first group received normal saline (0.9% NaCl) intraperitoneal and served as the control group. In the second group, acute pancreatitis was induced by 3.2-g/kg body weight L-arginine intraperitoneal twice at an interval of 1 hr, which has been shown previously to produce severe necrotizing acute pancreatitis. In the third group, NAC treatment (1000 mg/kg) was given after 1 hr of the induction of acute pancreatitis twice 24 hr apart. In the fourth group, animals received HBO, 6 hr after the induction of pancreatitis twice 12 hr apart. In the fifth group, animals received together NAC as in Group 3 and HBO treatment as in Group 4. Groups 1, 2, and 3 were left under normal atmospheric pressures. Twelve hours after last treatment, the animals were killed by exsanguinations. Blood samples were studied for amylase, calcium, and lactate dehydrogenase (LDH), pancreatic histology, pancreatic tissue malondialdehyde, superoxide dismutase, and glutathione levels.

RESULTS

Acute pancreatitis is reduced by the treatment of NAC, HBO, NAC + HBO. HBO + NAC groups performed statistically the best in preventing L-arginine-induced acute necrotising pancreatitis.

CONCLUSIONS

NAC especially combined with HBO, decreases oxidative stress parameters, serum amylase, calcium, and LDH levels, as well as histopathologic score.

Reactive oxygen and nitrogen species modulate the ex-vivo effects of LPS on platelet adhesion to fibrinogen

AIMS

Excessive production of nitric oxide (NO) and reactive oxygen species (ROS) in sepsis modulates different cell functions. Since the sepsis severity is associated with the degree of platelet activation, we decided to investigate the role of systemic generation of NO and ROS in modulating the platelet adhesion of lipopolysaccharide (LPS)-treated rats.

MAIN METHODS

Platelet adhesion was evaluated using fibrinogen-coated 96-well microtiter plates. Cyclic GMP levels were measured using enzyme immunoassay kit.

KEY FINDINGS

Treatment of rats with LPS significantly increased spontaneous platelet adhesion, but reduced the thrombin-activated platelet adhesion when compared with control rats. Chronic treatment of rats with the NO synthase inhibitor L-NAME (20 mg/rat/day, 7 days) prior to LPS injection normalized the increased adhesion in non-activated platelets, but failed to affect the adhesion in thrombin-activated platelets. The cGMP levels were modified neither in non-activated nor in thrombin-activated platelets of LPS-treated rats when compared with control rats. The incubation of non-activated platelets with the O2- scavenger PEG-SOD reversed the stimulatory effect of LPS on spontaneous adhesion, but had no effect in stimulated-platelet adhesion of non-treated or LPS-treated groups. Moreover, pretreatment of rats with the antioxidant N-acetylcysteine (NAC; 150 mg/kg) prevented the increase of non-activated platelet adhesion, and significantly reduced the inhibitory effect of LPS on thrombin-stimulated adhesion.

SIGNIFICANCE

Our findings suggest that in LPS-treated rats, NO plays an important modulatory role only in non-stimulated platelet adhesion through cGMP-independent mechanisms, while ROS, directly or by affecting the redox state of the animals, modulates both non-activated and thrombin-activated platelet adhesion.

Effects of L-canavanine and ozone on vascular reactivity in septicemic rats

Septicemia leads to oxidative stress with overproduction of reactive-oxygen species (ROS) and consumption of endogenous antioxidant enzymes. We tested a twofold hypothesis: (1) does oxidative stress (OxS) induced by sepsis acting alone or in concert with augmented inflammatory processes contributes to sepsis-related vascular dysfunction, and, (2) whether ozone (O(3)) and L-canavanine (CAV) mitigate the negative impact of the aforementioned phenomena. We investigated the relative impact of treatment with CAV and/or O(3) on vascular OxS associated vascular functional changes in septicemic rats. For this study, 60 male Sprague-Dawley rats were used and divided into six experimental groups (n = 10): control group (C), sham-operated (Sham), septicemic rats (S), S rats treated with CAV (100 mg/kg. i.p; S + CAV), S rats treated with O(3) (1.2 mg/kg, i.p.; S + O(3)) and S rats treated with both O(3) and CAV (S + O(3) + CAV). After 22 h, the mean arterial blood pressure (MAP), the aortic ring vascular reactivity to phenylephrine, abdominal aortic blood flow (AABF), serum tumor necrosis factor-alpha (TNF-alpha) and plasma nitrite/nitrate (NOx) concentration were measured. In addition, hepatic antioxidant enzyme activities sodium dismutase (SOD) and glutathione peroxidase (GSH-Px) were estimated. Septicemia caused significant elevation of serum TNF-alpha (p < 0.001) and plasma NOx (p < 0.001) and significant (p < 0.001) reduction of AABF (p < 0.001), aortic vascular response to phenylephrine (p < 0.001), MAP (p < 0.001) and hepatic SOD and GSH-Px activity (p < 0.001) compared with the C group, while treatment with O(3) and/or CAV induced significant amelioration of all those increases. Abnormalities were attenuated to a similar extent with treatment with both O(3) and CAV. These results suggested that concomitant administration of O(3) and CAV alleviated the compromised vascular reactivity in septicemic conditions and prevent its progression into septic shock compared with each alone.