Reactive oxygen species, antioxidant mechanisms and serum cytokine levels in cancer patients: impact of an antioxidant treatment

Unveiling the Multifaceted Management of Oral Mucositis in Cancer Patients: A Narrative Review

Oral mucositis (OM) is a major and common adverse reaction to cancer treatment, occurring in all patients who undergo radiation therapy or chemotherapy that includes the mucosal areas of the oral and oropharyngeal region. The pathophysiology of OM remains incompletely understood, and there are many unanswered questions about the risk factors for developing OM. Multidisciplinary clinicians and researchers must collaborate to better understand and expand treatment strategies for OM and other inflammatory conditions in oncology. This will lead to the development of more effective treatments and reduce the burden of OM in cancer patients. This article comprehensively reviews the risk factors and patient factors associated with OM, its pathogenesis, clinical presentation, grading, and management.

Targeting the Metabolic Paradigms in Cancer and Diabetes

Dysregulated metabolic dynamics are evident in both cancer and diabetes, with metabolic alterations representing a facet of the myriad changes observed in these conditions. This review delves into the commonalities in metabolism between cancer and type 2 diabetes (T2D), focusing specifically on the contrasting roles of oxidative phosphorylation (OXPHOS) and glycolysis as primary energy-generating pathways within cells. Building on earlier research, we explore how a shift towards one pathway over the other serves as a foundational aspect in the development of cancer and T2D. Unlike previous reviews, we posit that this shift may occur in seemingly opposing yet complementary directions, akin to the Yin and Yang concept. These metabolic fluctuations reveal an intricate network of underlying defective signaling pathways, orchestrating the pathogenesis and progression of each disease. The Warburg phenomenon, characterized by the prevalence of aerobic glycolysis over minimal to no OXPHOS, emerges as the predominant metabolic phenotype in cancer. Conversely, in T2D, the prevailing metabolic paradigm has traditionally been perceived in terms of discrete irregularities rather than an OXPHOS-to-glycolysis shift. Throughout T2D pathogenesis, OXPHOS remains consistently heightened due to chronic hyperglycemia or hyperinsulinemia. In advanced insulin resistance and T2D, the metabolic landscape becomes more complex, featuring differential tissue-specific alterations that affect OXPHOS. Recent findings suggest that addressing the metabolic imbalance in both cancer and diabetes could offer an effective treatment strategy. Numerous pharmaceutical and nutritional modalities exhibiting therapeutic effects in both conditions ultimately modulate the OXPHOS-glycolysis axis. Noteworthy nutritional adjuncts, such as alpha-lipoic acid, flavonoids, and glutamine, demonstrate the ability to reprogram metabolism, exerting anti-tumor and anti-diabetic effects. Similarly, pharmacological agents like metformin exhibit therapeutic efficacy in both T2D and cancer. This review discusses the molecular mechanisms underlying these metabolic shifts and explores promising therapeutic strategies aimed at reversing the metabolic imbalance in both disease scenarios.

Chemotherapy agents reduce protein synthesis and ribosomal capacity in myotubes independent of oxidative stress

Chemotherapeutic agents (CAs) are first-line antineoplastic treatments against a wide variety of cancers. Despite their effectiveness in halting tumor progression, side effects associated with CAs promote muscle loss by incompletely understood mechanisms. To address this problem, we first identified how oxidative stress impairs protein synthesis in C2C12 myotubes. Transient elevations in reactive oxygen species (ROS) resulted in protein synthesis deficits and reduced ribosomal (r)RNA levels. Oxidative stress did not reduce rRNA gene (rDNA) transcription, but it caused an increase in rRNA and protein oxidation. To determine whether CAs affect protein synthesis independent of oxidative stress, we exposed myotubes to Paclitaxel (PTX), Doxorubicin (DXR), or Marizomib (Mzb) at doses that did result in elevated ROS levels (sub-ROS). Exposure to CAs reduced protein synthesis and rRNA levels, but unlike oxidative stress, sub-ROS exposures impaired rDNA transcription. These results indicate that although oxidative stress disrupts protein synthesis by compromising ribosomal quantity and quality, CAs at sub-ROS doses compromise protein synthesis and ribosomal capacity, at least in part, by reducing rDNA transcription. Therefore, CAs negatively impact protein synthesis by causing oxidative stress in addition to directly reducing the ribosomal capacity of myotubes in a ROS-independent manner.

Redox modulation of vitagenes via plant polyphenols and vitamin D: Novel insights for chemoprevention and therapeutic interventions based on organoid technology

Polyphenols are chemopreventive through the induction of nuclear factor erythroid 2 related factor 2 (Nrf2)-mediated proteins and anti-inflammatory pathways. These pathways, encoding cytoprotective vitagenes, include heat shock proteins, such as heat shock protein 70 (Hsp70) and heme oxygenase-1 (HO-1), as well as glutathione redox system to protect against cancer initiation and progression. Phytochemicals exhibit biphasic dose responses on cancer cells, activating at low dose, signaling pathways resulting in upregulation of vitagenes, as in the case of the Nrf2 pathway upregulated by hydroxytyrosol (HT) or curcumin and NAD/NADH-sirtuin-1 activated by resveratrol. Here, the importance of vitagenes in redox stress response and autophagy mechanisms, as well as the potential use of dietary antioxidants in the prevention and treatment of multiple types of cancer are discussed. We also discuss the possible relationship between SARS-CoV-2, inflammation and cancer, exploiting innovative therapeutic approaches with HT-rich aqueous olive pulp extract (Hidrox®), a natural polyphenolic formulation, as well as the rationale of Vitamin D supplementation. Finally, we describe innovative approaches with organoids technology to study human carcinogenesis in preclinical models from basic cancer research to clinical practice, suggesting patient-derived organoids as an innovative tool to test drug toxicity and drive personalized therapy.

Spectrophotometric assays for evaluation of Reactive Oxygen Species (ROS) in serum: general concepts and applications in dogs and humans

Reactive oxygen species (ROS) are reactive compounds derived from oxygen. In biological systems, an excessive amount of ROS can cause oxidative damage to biological macromolecules being involved in different diseases. Several assays have been developed in the last 30 years for ROS evaluation. The objective of this article will be to provide an update about the spectrophotometric methods currently used in the assessment of ROS in serum. The chemical basis of four different techniques will be reviewed, and examples of their possible applications will be provided. A particular emphasis about the practical applications of these assays in the dog will be made, but selected information about their use in humans will also be presented for comparative purposes, following a One-Health approach. The information about the spectrophotometric assays presented in this paper should be interpreted with caution once limited information about them is available yet, and further studies should be performed to clarify what they measure and their clinical application. Ideally, when applied to evaluate a sample's oxidative status, they should be incorporated in a panel of analytes where other oxidants, antioxidants, and biomarkers of inflammation were also included.

Alleviation of cisplatin-induced hepatotoxicity by gliclazide: Involvement of oxidative stress and caspase-3 activity

AIMS

Cisplatin (CP), as an effective alkylating agent, is widely used in cancer treatment, while hepatotoxicity is one of its side effects. Gliclazide (GLZ), as an oral hypoglycemic drug, has antioxidant and anti-inflammatory properties. This study was designed to investigate the protective effect of GLZ against CP-induced hepatotoxicity in mice.

METHODS

In this experimental study, 64 adult male mice randomly were allocated into eight groups (8 mice/group). Control, GLZ (5, 10, and 25 mg/kg, orally), CP (10 mg/kg, single dose, intraperitoneally), and CP+GLZ (in three doses). GLZ was administrated for 10 consecutive days. CP was injected on the 7th day of the study. At the end of the experiment, hepatotoxicity was evaluated by serum and tissue biochemical, histopathological, and immunohistochemical assessments.

RESULTS

The data were revealed that CP increased oxidative stress (increased MDA and reduced GSH), liver damage enzymes (ALT, AST, and ALP), and immunoreactivity of caspase-3 in liver tissue of CP-injected mice. Also, CP induced histopathological changes such as eosinophilic of hepatocytes, dilatation of sinusoids, congestion, and proliferation of Kupffer cells. GLZ administration significantly ameliorated serum functional enzyme and hepatic oxidative stress markers in CP-injected mice. In addition, the histological and immunohistochemical alterations were ameliorated in GLZ-treated mice. Of the three doses, 10 and 25 mg/kg were more effective.

CONCLUSIONS

In conclusion, GLZ with its antioxidant, anti-inflammatory, and anti-apoptotic activities, can be suggested as a promising drug in the treatment of CP-induced hepatotoxicity.

Are the oxidative stress levels in the tumor center and tumor boundary different from those in healthy tissue?

PURPOSE

This study aimed to investigate the relationship between oxidative stress levels in the tumor center, tumor edge, and healthy tissue.

METHODS

This study included a total of 53 patients with head and neck cancer. Samples of 5 × 5 × 5 mm were collected from the tumor center, tumor edge, and the healthy tissue. Total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) values were evaluated. (1) Oxidative stress values in the center and edge of all tumors and in healthy tissues were compared according to localization. (2) Tumors were divided into two groups as malignant (Group 1 [n = 28]: Laryngeal and tongue squamous cell cancers) and benign (Group 2 [n = 25]: Pleomorphic adenoma and Warthin tumors). The groups were compared according to the localization of the tissues.

RESULTS

The TOS value in the tumor edge was significantly higher than those in the tumor center and the healthy tissue. The TAS value in tissue located in the tumor edge was significantly higher than in the healthy tissue. The OSI value in the tumor edge was significantly higher than those in the tumor center and the healthy tissue. In all three localizations (tumor center, tumor edge, and healthy tissue), TOS and OSI values in Group 1 were significantly higher than Group 2.

CONCLUSION

Oxidative stress values in the tumor edge are significantly higher than the center of the tumor and healthy tissue. In malignant tumors, oxidative stress values are significantly higher in all localizations compared to benign tumors.

COVID-19 and cytokine storm syndrome: can what we know about interleukin-6 in ovarian cancer be applied?

Improving early diagnosis along with timely and effective treatment of COVID-19 are urgently needed. However, at present, the mechanisms underlying disease spread and development, defined prognosis, and immune status of patients with COVID-19 remain to be determined. Patients with severe disease state exhibit a hyperinflammatory response associated with cytokine storm syndrome, hypercoagulability, and depressed cell-mediated immunity. These clinical manifestations, sharing similar pathogenesis, have been well-studied in patients with advanced ovarian cancer. The present review suggests treatment approaches for COVID-19 based on strategies used against ovarian cancer, which shares similar immunopathology and associated coagulation disorders.The chronicization of the hyperinflammatory cytokine storm in patients with severe COVID-19 highlights a defective resistance phase that leads to aspecific chronic inflammation, associated with oxidative stress, which impairs specific T-cell response, induces tissue and endothelial damage, and thrombosis associated with systemic effects that lead to severe multi-organ failure and death. These events are similar to those observed in advanced ovarian cancer which share similar pathogenesis mediated primarily by Interleukin-6, which is, as well demonstrated in ovarian cancer, the key cytokine driving the immunopathology, related systemic symptoms, and patient prognosis.Consistent with findings in other disease models with similar immunopathology, such as advanced ovarian cancer, treatment of severe COVID-19 infection should target inflammation, oxidative stress, coagulation disorders, and immunodepression to improve patient outcome. Correctly identifying disease stages, based on available laboratory data, and developing a specific protocol for each phase is essential for effective treatment.

Elucidation of the inhibition mechanism of sulfiredoxin using molecular modeling and development of its inhibitors

When intracellular reactive oxygen species (ROS) increase, cancer cells are more vulnerable to oxidative stress compared to normal cells; thus, the collapse of redox homeostasis can lead to selective death of cancer cells. Indeed, recent studies have shown that inhibition of sulfiredoxin (Srx), which participates in antioxidant mechanisms, induces ROS-mediated cancer cell death. In this paper, we describe how an Srx inhibitor, J14 (4-[[[4-[4-(2-chlor-ophenyl)-1-piperazinyl]-6-phenyl-2-pyrimidinyl]thio]methyl]-benzoic acid), interferes with the antioxidant activity of Srx at the molecular level. We searched for possible binding sites of Srx using a binding site prediction method and uncovered two possible inhibition mechanisms of Srx by J14. Using molecular dynamics simulations and binding free energy calculations, we confirmed that J14 binds to the ATP binding site; therefore, J14 acts as a competitive inhibitor of ATP, settling the question of the two mechanisms. Based on the inhibition mechanism revealed at the atomic level, we designed several derivatives of J14, which led to LMT-328 (4-(((4-(4-(2-Chlorophenyl)piperazin-1-yl)-6-(2,4-dihydroxy-5-isopropylphenyl)pyrimidin-2-yl)thio)methyl)benzoic acid), which is possibly an even more potent inhibitor than J14.

Systemic redox status in lung cancer patients is related to altered glucose metabolism

Altered systemic redox status is often observed in lung cancer. However, detailed information on factors other, than smoking, which influence this perturbation is rather scarce. Elevated oxidative stress has been linked with disturbances in glucose metabolism before, but such associations have not been investigated in lung cancer. The aim of this study was to evaluate the relationship between systemic parameters of glucose metabolism and redox status in lung cancer patients (LC). Biochemical variables related to circulating glucose, i.e. glucose, insulin, c-peptide, fructosamine (FA), and glucose metabolism, i.e. β-hydroxybutyrate (BHB), lactate (LACT), non-esterified fatty acids (NEFAs), as well as redox status i.e. total antioxidant status (TAS) and total oxidant status (TOS) were determined for LC (n = 122) and control subjects (CS) (n = 84). HOMA-IR and the oxidative stress index (OSI) were calculated. LC patients had an altered redox status and glucose metabolism compared to CS. Positive correlations in LC were observed between TOS, OSI and circulating glucose as well as FA, while TAS positively correlated with BHB and NEFAs. In contrast, in metastatic LC, NEFAs and BHB positively correlated with OSI. Smoking status additionally stratified the observed relationships. In conclusion, we found that parameters related to circulating glucose or non-enzymatic glycation were correlated with oxidative stress (TOS and OSI), while metabolites such as BHB and NEFAs were correlated with antioxidant capacity (TAS). Metastasis prevalence and smoking seem to influence these correlations. However, the detailed mechanism of this relationship requires further research, in particular as regards the surprising positive correlation between NEFAs and TAS.

Association Between Oxidative Stress and Melanoma Progression

BACKGROUND

Overproduction of free radicals accompanied with their insufficient removal/neutralization by antioxidative defense system impairs redox hemostasis in living organisms. Oxidative stress has been shown to be involved in all the stages of carcinogenesis and malignant melanocyte transformation. The aim of this study was to examine association between oxidative stress development and different stages of melanoma.

METHODS

The measured oxidative stress parameters included: superoxide anion radical, total and manganese superoxide dismutase, catalase and malondialdehyde. Oxidative stress parameters were measured spectrophotometrically in serum samples from melanoma patients (n=72) and healthy control subjects (n=30). Patients were classified according to AJCC clinical stage.

RESULTS

Average superoxide anion and malondialdehyde concentrations were significantly higher in melanoma patients than in control group, with the highest value of superoxide anion in stage III, while malondialdehyde highest value was in stage IV. The activity of total and manganese superoxide dismutase was insignificantly higher in melanoma patients than in control group, while catalase activity was significantly higher. The highest activity of total activity of manganese superoxide dismutase was in stage IV. Catalase activity was increasing with the disease progression achieving the maximum in stage III.

CONCLUSION

Results of our study suggest that melanoma is oxidative stress associated disease, as well as deteriorated cell functioning at mitochondrial level.

Protective effect of Salvia miltiorrhiza Bunge on 5-fluorouracil-induced oral mucositis

Oral mucositis is a common side-effect caused by chemotherapy or radiotherapy occurring in the majority of cancer patients and is characterized by inflammation and ulcers in the oral mucosa. In the present study, we examined the protective effects of Salvia miltiorrhiza Bunge (SM) on oral mucositis induced by 5-fluorouracil (5-FU) in human pharyngeal cells and golden Syrian hamsters. We investigated the proliferation and antioxidant abilities of SM using MTT, 2-diphenyl-1-picrylhydrazyl (DPPH) and reactive oxygen species (ROS) assays in vitro. Additionally, TUNEL assay was performed, and the expression levels of nuclear factor-κB (NF-κB), caspase-3 and proinflammatory cytokines were assessed by immunoblotting. The results showed that SM increased the cell proliferation rate in human pharyngeal cells up to 128.97±9.7% compared with this rate in the untreated cells and exerted protective effects on mucosal injury caused by 5-FU treatment. In addition, all concentrations of SM increased DPPH scavenging ability and blocked ROS generation in the treated cells. Taken together, following SM treatment, expression of NF-κB and cleaved caspase-3 were significantly decreased followed by inhibition of cell death. These data suggest that SM could be used for the prevention and treatment of oral mucositis caused by cancer therapies.

The Janus-Faced Role of Antioxidants in Cancer Cachexia: New Insights on the Established Concepts

Chronic inflammation and excessive loss of skeletal muscle usually occur during cancer cachexia, leading to functional impairment and delaying the cure of cancer. The release of cytokines by tumor promotes the formation of reactive oxygen species (ROS), which in turn regulate catabolic pathways involved in muscle atrophy. ROS also exert a dual role within tumor itself, as they can either promote proliferation and vascularization or induce senescence and apoptosis. Accordingly, previous studies that used antioxidants to modulate these ROS-dependent mechanisms, in cancer and cancer cachexia, have obtained contradictory results, hence the need to gather the main findings of these studies and draw global conclusions in order to stimulate more oriented research in this field. Based on the literature reviewed in this paper, it appears that antioxidant supplementation is (1) beneficial in cancer cachectic patients with antioxidant deficiencies, (2) most likely harmful in cancer patients with adequate antioxidant status (i.e., lung, gastrointestinal, head and neck, and esophageal), and (3) not recommended when undergoing radiotherapy. At the moment, measuring the blood levels of antioxidants may help to identify patients with systemic deficiencies. This approach is simple to realize but could not be a gold standard method for cachexia, as it does not necessarily reflect the redox state in other organs, like muscle.

Micronutrients in Oncological Intervention

Nutritional supplements are widely used among patients with cancer who perceive them to be anticancer and antitoxicity agents. Depending on the type of malignancy and the gender 30%-90% of the cancer patients supplement their diets with antioxidant and immuno-stabilizing micronutrients, such as selenium, vitamin C, and vitamin D, often without the knowledge of the treating physician. From the oncological viewpoint, there are justifiable concerns that dietary supplements decrease the effectiveness of chemotherapy and radiotherapy. Recent studies, however, have provided increasing evidence that treatment is tolerated better-with an increase in patient compliance and a lower rate of treatment discontinuations-when micronutrients, such as selenium, are added as appropriate to the patient's medication. Nutritional supplementation tailored to an individual's background diet, genetics, tumor histology, and treatments may yield benefits in subsets of patients. Clinicians should have an open dialogue with patients about nutritional supplements. Supplement advice needs to be individualized and come from a credible source, and it is best communicated by the physician.

Effects of ghrelin, leptin and melatonin on the levels of reactive oxygen species, antioxidant enzyme activity and viability of the HCT 116 human colorectal carcinoma cell line

Obesity is associated with an increased risk of certain types of cancer, including colon cancer. Adipose tissue is an endocrine organ that produces biologically active substances, such as leptin and ghrelin. Recent research has suggested that adipose-derived hormones may be associated with mechanisms linked to tumorigenesis and cancer progression. Furthermore, previous studies have demonstrated that pineal gland-derived melatonin possesses important oncostatic and antioxidant properties. The present study aimed to determine the effects of the adipokines ghrelin and leptin, and the melatonin on intracellular levels of reactive oxygen species (ROS) and the activity of selected antioxidant enzymes, such as superoxide dismutase, catalase (CAT) and glutathione peroxidase. The effects of these compounds were also determined on the viability of HCT 116 human colorectal carcinoma cells in vitro. The pro-oxidant and growth inhibitory effects of melatonin resulted in an accumulation of ROS and decreased antioxidant capacity in melatonin-treated cells. Ghrelin administration alone caused a significant decrease in the levels of ROS, due to an increased activity of CAT in the HCT 116 cells. In addition, the present study observed increased lipid peroxidation following melatonin treatment, and decreased levels of malondialdehyde following ghrelin or leptin treatment. In conclusion, ghrelin, leptin and melatonin have various influences on the antioxidant capacity of HCT 116 cells. Compared with the adipokines, treatment with melatonin increased ROS levels and decreased cellular viability.

Oxidative stress level is not associated with survival in terminally ill cancer patients: a preliminary study

Background

While cancer patients have higher oxidative stress (OS) and lower antioxidant activity, evidence for the association of these parameters with survival in patients with terminally ill cancer is lacking.

Methods

We followed 65 terminal cancer patients prospectively. We assessed their performance status, some symptoms, and serum levels of vitamin C and OS level. The Gehan’s generalized Wilcoxon test was used to examine the association between survival times and variables.

Results

Subjects’ performance status was very poor and they had a high level of OS and a low level of vitamin C. No significant association of these two parameters with survival time was noted (p-value, 0.637 for high OS and 0.240 for low vitamin C). Poor performance status was independently related to high OS status after adjusting for potential confounders (adjusted OR, 4.45; p-value, 0.031).

Conclusions

In this study, OS was not associated with survival of terminally ill cancer patients and its prognostic role requires further study.

Chain-shattering polymeric therapeutics with on-demand drug-release capability

Design of smart polymeric therapeutics

We designed and synthesized trigger-responsive chain-shattering polymeric therapeutics (CSPTs) via condensation polymerization of a UV-or hydrogen peroxide-responsive domain and a bisfunctional drug as co-monomers. CSPTs have precisely controlled molecular composition and unique chain-shattering type of drug release mechanism. Drug release kinetics can be precisely controlled by means of the trigger treatment. Chemotherapeutic-containing CSPTs showed trigger-responsive in vitro and in vivo antitumor efficacy.

Distribution of selenium and oxidative stress in breast tumor-bearing mice

The present study investigated the effects of breast tumors on the blood and tissue distribution of essential trace mineral selenium (Se), and oxidative stress status of mice. Female 10-week-old BALB/cByJNarl mice were randomly assigned into control (CNL) and breast tumor-bearing (TB) groups. TB mice were injected subcutaneously into the right hind thigh with 5 × 10(6) EMT6 mouse mammary tumor cells. After 22 days, we measured Se concentrations, Se-dependent glutathione peroxidase (GPx) activities, and malondialdehyde (MDA) products (indicator of oxidative stress) in plasma, various tissues, and plasma vascular endothelial growth factor (VEGF) concentrations. There were no significant differences in body weights and daily intake between both groups. Compared with the CNL group, TB mice have decreases in plasma Se concentrations and GPx activities, as well as higher plasma VEGF and MDA concentrations. Plasma Se concentrations were also negatively correlated with plasma MDA and VEGF concentrations. Furthermore, tissue Se concentrations and GPx activities in TB animals were lower; whereas the MDA concentrations higher in various tissues including liver, kidney, brain, lung, spleen, and thymic tissues. In conclusion, disruption of Se homeostasis critically reflects oxidative stress in target tissues, thus may increase the risk for progression of breast cancer and metastasis.

Intravenous vitamin C administration reduces fatigue in office workers: a double-blind randomized controlled trial

Background

Studies of the efficacy of vitamin C treatment for fatigue have yielded inconsistent results. One of the reasons for this inconsistency could be the difference in delivery routes. Therefore, we planned a clinical trial with intravenous vitamin C administration.

Methods

We evaluated the effect of intravenous vitamin C on fatigue in office workers. A group of 141 healthy volunteers, aged 20 to 49 years participated in this randomized, double-blind, controlled clinical trial. The trial group received 10 grams of vitamin C with normal saline intravenously, while the placebo group received normal saline only. Since vitamin C is a well-known antioxidant, oxidative stress was measured. Fatigue score, oxidative stress, and plasma vitamin C levels were measured before intervention, and again two hours and one day after intervention. Adverse events were monitored.

Results

The fatigue scores measured at two hours after intervention and one day after intervention were significantly different between the two groups (p = 0.004); fatigue scores decreased in the vitamin C group after two hours and remained lower for one day. Trial also led to higher plasma vitamin C levels and lower oxidative stress compared to the placebo group (p < 0.001, p < 0.001, respectively). When data analysis was refined by dividing each group into high-baseline and low-baseline subgroups, it was observed that fatigue was reduced in the lower baseline vitamin C level group after two hours and after one day (p = 0.004). The same did not hold for the higher baseline group (p = 0.206).

Conclusion

Thus, intravenous vitamin C reduced fatigue at two hours, and the effect persisted for one day. There were no significant differences in adverse events between two groups. High dose intravenous vitamin C proved to be safe and effective against fatigue in this study.

Trial Registration

The clinical trial registration of this trial is http://ClinicalTrials.govNCT00633581.

Effect of Waon therapy on oxidative stress in chronic heart failure

BACKGROUND

A previous report by our team showed that Waon therapy, using a far infrared-ray dry sauna at 60°C, improves cardiac and vascular function in patients with chronic heart failure (CHF). The purpose of the present study was to clarify the effect of Waon therapy on oxidative stress in CHF patients and investigate its mechanism by animal experiments.

METHODS AND RESULTS

Forty patients with CHF were divided into control (n=20) and Waon therapy (n=20) groups. All patients received standard optimal medications for CHF. Waon therapy group was treated with Waon therapy daily for 4 weeks. After 4 weeks of Waon therapy, concentrations of hydroperoxide and brain natriuretic peptide (BNP) decreased significantly (hydroperoxide, 422±116 to 327±88U.CARR, P<0.001; BNP, 402±221 to 225±137pg/ml, P<0.001), and the nitric oxide metabolites increased (71.2±35.4 to 92.0±40.5mmol/L, P<0.05). In contrast, none of these variables changed over the 4-week interval in the control group. Furthermore, animal experiments were performed using TO-2 cardiomyopathic hamsters. On immunohistochemistry, cardiac expression of 4-hydroxy-2-nonenal, a marker of oxidative stress, was decreased in the 4-week Waon therapy compared to untreated hamsters. On Western blotting, cardiac expressions of heat shock protein (HSP) 27, manganese superoxide dismutase and HSP32, which reduce oxidative stress, were significantly upregulated in the 4-week Waon therapy compared to untreated hamsters.

CONCLUSIONS

Waon therapy decreases oxidative stress in patients and hamsters with heart failure.

The autophagic tumor stroma model of cancer or "battery-operated tumor growth": A simple solution to the autophagy paradox

The role of autophagy in tumorigenesis is controversial. Both autophagy inhibitors (chloroquine) and autophagy promoters (rapamycin) block tumorigenesis by unknown mechanism(s). This is called the "Autophagy Paradox". We have recently reported a simple solution to this paradox. We demonstrated that epithelial cancer cells use oxidative stress to induce autophagy in the tumor microenvironment. As a consequence, the autophagic tumor stroma generates recycled nutrients that can then be used as chemical building blocks by anabolic epithelial cancer cells. This model results in a net energy transfer from the tumor stroma to epithelial cancer cells (an energy imbalance), thereby promoting tumor growth. This net energy transfer is both unilateral and vectorial, from the tumor stroma to the epithelial cancer cells, representing a true host-parasite relationship. We have termed this new paradigm "The Autophagic Tumor Stroma Model of Cancer Cell Metabolism" or "Battery-Operated Tumor Growth". In this sense, autophagy in the tumor stroma serves as a "battery" to fuel tumor growth, progression and metastasis, independently of angiogenesis. Using this model, the systemic induction of autophagy will prevent epithelial cancer cells from using recycled nutrients, while the systemic inhibiton of autophagy will prevent stromal cells from producing recycled nutrients-both effectively "starving" cancer cells. We discuss the idea that tumor cells could become resistant to the systemic induction of autophagy, by the upregulation of natural endogenous autophagy inhibitors in cancer cells. Alternatively, tumor cells could also become resistant to the systemic induction of autophagy, by the genetic silencing/deletion of pro-autophagic molecules, such as Beclin1. If autophagy resistance develops in cancer cells, then the systemic inhibition of autophagy would provide a therapeutic solution to this type of drug resistance, as it would still target autophagy in the tumor stroma. As such, an anti-cancer therapy that combines the alternating use of both autophagy promoters and autophagy inhibitors would be expected to prevent the onset of drug resistance. We also discuss why anti-angiogenic therapy has been found to promote tumor recurrence, progression and metastasis. More specifically, anti-angiogenic therapy would induce autophagy in the tumor stroma via the induction of stromal hypoxia, thereby converting a non-aggressive tumor type to a "lethal" aggressive tumor phenotype. Thus, uncoupling the metabolic parasitic relationship between cancer cells and an autophagic tumor stroma may hold great promise for anti-cancer therapy. Finally, we believe that autophagy in the tumor stroma is the local microscopic counterpart of systemic wasting (cancer-associated cachexia), which is associated with advanced and metastatic cancers. Cachexia in cancer patients is not due to decreased energy intake, but instead involves an increased basal metabolic rate and increased energy expenditures, resulting in a negative energy balance. Importantly, when tumors were surgically excised, this increased metabolic rate returned to normal levels. This view of cachexia, resulting in energy transfer to the tumor, is consistent with our hypothesis. So, cancer-associated cachexia may start locally as stromal autophagy, and then spread systemically. As such, stromal autophagy may be the requisite precursor of systemic cancer-associated cachexia.

Understanding the "lethal" drivers of tumor-stroma co-evolution: emerging role(s) for hypoxia, oxidative stress and autophagy/mitophagy in the tumor micro-environment

We have recently proposed a new model for understanding how tumors evolve. To achieve successful "Tumor-Stroma Co-Evolution", cancer cells induce oxidative stress in adjacent fibroblasts and possibly other stromal cells. Oxidative stress in the tumor stroma mimics the effects of hypoxia, under aerobic conditions, resulting in an excess production of reactive oxygen species (ROS). Excess stromal production of ROS drives the onset of an anti-oxidant defense in adjacent cancer cells, protecting them from apoptosis. Moreover, excess stromal ROS production has a "Bystander-Effect", leading to DNA damage and aneuploidy in adjacent cancer cells, both hallmarks of genomic instability. Finally, ROS-driven oxidative stress induces autophagy and mitophagy in the tumor micro-environment, leading to the stromal over-production of recycled nutrients (including energy-rich metabolites, such as ketones and L-lactate). These recycled nutrients or chemical building blocks then help drive mitochondrial biogenesis in cancer cells, thereby promoting the anabolic growth of cancer cells (via an energy imbalance). We also show that ketones and lactate help "fuel" tumor growth and cancer cell metastasis and can act as chemo-attractants for cancer cells. We have termed this new paradigm for accelerating tumor-stroma co-evolution, "The Autophagic Tumor Stroma Model of Cancer Cell Metabolism". Heterotypic signaling in cancer-associated fibroblasts activates the transcription factors HIF1alpha and NFκB, potentiating the onset of hypoxic and inflammatory response(s), which further upregulates the autophagic program in the stromal compartment. Via stromal autophagy, this hypoxic/inflammatory response may provide a new escape mechanism for cancer cells during anti-angiogenic therapy, further exacerbating tumor recurrence and metastasis.

Selenium modifies the osteoblast inflammatory stress response to bone metastatic breast cancer

Breast cancer frequently metastasizes to the skeleton resulting in bone degradation due to osteoclast activation. Metastases also downregulate differentiation and the bone-rebuilding function of osteoblasts. Moreover, cancer cells trigger osteoblast inflammatory stress responses. Pro-inflammatory mediators such as interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), expressed by osteoblasts (MC3T3-E1) stimulated with human breast cancer cell (MDA-MB-231) conditioned medium, are pivotal to osteoclast activation and metastasis. Given that these genes are regulated by nuclear factor-kappaB (NF-kappaB), a redox-sensitive transcription factor, we hypothesized that selenium (Se) could abrogate the inflammatory response to metastatic breast cancer cells by modulating NF-kappaB. Caffeic acid phenethyl ester and parthenolide inhibited NF-kappaB activation, as seen by gel shift assays and immunoblotting for p65 in nuclear fractions, as well as decreased production of IL-6 and MCP-1. Supplementation of MC3T3-E1 with methylseleninic acid (MSA) (0.5 microM to 4 microM) reduced the activation of NF-kappaB leading to a decrease in IL-6, MCP-1, COX-2 and iNOS in response to MDA-MB-231 conditioned medium. Addition of MSA to osteoblasts for as little as 15 min suppressed activation of NF-kappaB suggesting that short-lived active metabolites might be involved. However, brief exposure to MSA also brought about an increase in selenoprotein glutathione peroxidase 1. In summary, our data indicate that the osteoblast response to metastatic breast cancer cells is regulated by NF-kappaB activation, which can be effectively suppressed by MSA either through short-lived active metabolites and/or selenoproteins. Thus, Se supplementation may prevent the osteoblast inflammatory response or dampen the vicious cycle established when breast cancer cells, osteoblasts and osteoclasts interact.

Carbocysteine: clinical experience and new perspectives in the treatment of chronic inflammatory diseases

BACKGROUND

Carbocysteine is a muco-active drug with free radical scavenging and anti-inflammatory properties. It is actually approved for clinical use as adjunctive therapy of respiratory tract disorders characterized by excessive, viscous mucus, including chronic obstructive airways disease (COPD).

OBJECTIVE

The intriguing antioxidant and anti-inflammatory properties of carbocysteine, beyond its known mucolytic activity, are described to explain its therapeutic efficacy and suggest new clinical uses.

METHODS

After reviewing physiology and preclinical studies, human studies on the use of carbocysteine in chronic inflammatory diseases, i.e., COPD and cancer cachexia, are reviewed.

RESULTS/CONCLUSIONS

Carbocysteine has been recently recognized as an effective and safe treatment for the long-term management of COPD, able to reduce the incidence of exacerbations and improve patient quality of life. Moreover, carbocysteine was effective in counteracting some symptoms associated with cancer cachexia. Preclinical and clinical studies have demonstrated that the antioxidant and anti-inflammatory properties of carbocysteine are more important than mucolysis itself for its therapeutic efficacy. Therefore, carbocysteine may be able to reverse the oxidative stress associated with several chronic inflammatory diseases, such as cardiovascular diseases and neurodegenerative disorders. Controlled, randomized studies in humans are warranted.

Current trends in the management of oral mucositis related to cancer treatment

Oral mucositis is one of the most common toxicities observed during radiotherapy and chemotherapy treatment for cancers. Mucositis results in sore mouth, altered taste sensation, pain and dysphagia leading to malnutrition. Left untreated, oral mucositis leads to ulceration, orodental infection, bleeding and discontinuation of effective radiotherapy or chemotherapy. Frequent hospitalization, enteral or parenteral nutrition, increased demand for analgesics ultimately account for increased cost of healthcare. Quantification of oral mucositis using standardized grading system is important for appropriate evaluation, reporting and management. In the recent past there is a paradigm shift in the pathobiology of cancer therapy related mucositis. Clear understanding of its pathogenesis is essential for the formulation of effective mucositis care. Numerous drug therapies, radiation techniques and oral care protocols have been tried in the past to reduce oral mucositis, None have proven to be consistently effective. Current trends for the prevention and treatment of oral mucositis is multi-targeted treatment supplemented by aggressive oral hygiene, reactive oxygen species (ROS) inhibitors, growth factors and use of specific topical agents to improve treatment of oral mucositis in future.

Oxidative stress with altered element content and decreased ATP level of erythrocytes in hepatocellular carcinoma and colorectal liver metastases

Our aim was to study the possible alterations of redox status (enzymatic and nonenzymatic parameters and metal elements) in erythrocytes of patients with hepatocellular carcinoma (HCC), colorectal liver metastases (CRLM) and benign liver neoplasms. The function of redox homeostasis is closely connected to the energy level of erythrocytes, therefore, the ATP level was also determined. Antioxidant parameters, enzyme activities of superoxide dismutase and glutathione peroxidase were estimated in the erythrocytes of 11 patients with benign tumour, 23 patients with primary malignant and 37 metastatic liver tumour patients and 30 age-matched and sex-matched healthy controls. Element content with inductively coupled plasma optical emission spectrometer and ATP level by the chemiluminometric method were also determined from the samples. Free radical intensity was significantly increased, whereas erythrocyte glutathione peroxidase and superoxide dismutase activities were significantly decreased in the HCC and CRLM groups versus benign groups and controls. Se, Mn and Zn levels were lowered in HCC and CRLM groups versus benign and control groups. The content of Cu, Mg, Se and Zn changed significantly between HCC and CRLM groups. Similarly, ATP concentration decreased in HCC and CRLM versus controls and benign groups. The lowest levels of ATP and antioxidant enzyme activities were found in the case of CRLM patients. These results reveal an alteration in the ATP level of erythrocytes with concomitant changes in the antioxidant defence system in hepatic cancer patients. Altered redox homeostasis (oxidative damage) may lead to decreased ATP level and consequently may play an important role in primary carcinogenesis and generation of metastases, as well.

Muscle wasting in diabetic and in tumor-bearing rats: role of oxidative stress

Cachexia is a debilitating syndrome characterized by body weight loss, muscle wasting, and anemia. Muscle wasting results from an altered balance between protein synthesis and degradation rates. Reactive oxygen species are indicated as crucial players in the onset of muscle protein hypercatabolism by upregulating elements of the ubiquitin-proteasome pathway. The present study has been aimed at evaluating comparatively the involvement of oxidative stress in the pathogenesis of skeletal muscle wasting in two different experimental models: rats rendered hyperglycemic by treatment with streptozotocin and rats bearing the Yoshida AH-130 ascites hepatoma. For this purpose, both tumor bearers and diabetic animals have been treated with dehydroepiandrosterone (DHEA), a multifunctional steroid endowed with multitargeted antioxidant properties. We show that diabetic rats and AH-130 rats share several features, hypoinsulinemia, occurrence of oxidative stress, and positive response to DHEA administration, although the extent of the effects of DHEA largely differs between diabetic animals and tumor-bearing rats. The hypercatabolism, evaluated in terms of proteasome activity and expression of atrogin-1 and MuRF1, is activated in AH-130 rats, whereas it is lacking in streptozotocin-treated rats. Moreover, we demonstrate that the role of oxidative stress can interfere with muscle wasting through different mechanisms, not necessarily involving NF-kappaB activation. In conclusion, the present results show that, although skeletal muscle wasting occurs in both diabetic rats and tumor-host rats, the underlying mechanisms are different. Moreover, despite oxidative stress being detectable in both experimental models, its contribution to muscle wasting is not comparable.

Oxidative stress in lymphocytes, neutrophils, and serum of oral cavity cancer patients: modulatory array of L-glutamine

OBJECTIVES

Our aim was to assess the oxidative stress and ameliorative effect of L-glutamine in serum, neutrophils, and lymphocytes of oral cancer patients by measuring the levels of malondialdehyde (MDA) and antioxidants.

MATERIALS AND METHODS

This study has been conducted on serum and specific blood cells in adult, male oral cancer patients (stage III-6, stage IV-42) and normal subjects of an equal number of age and sex-matched disease-free healthy subjects. The levels of lipid peroxidation and antioxidant enzymes were assayed using spectrophotometric methods.

RESULTS

MDA levels were elevated, and antioxidant enzyme status was decreased significantly in all groups of cancer patients simultaneously, but after supplementation of "glutammune" (66.66% L-glutamine), oxidative stress has been alleviated to some extent; especially, it has repaired the glutathione cascade system.

CONCLUSION

We conclude that oxidative stress is due to the enhanced lipid peroxidation and decrease in antioxidant enzymes, and it can be restored with dietary supplementation of L-glutamine related drug.

Immunomodulatory effect of vitamin C on intracytoplasmic cytokine production in neonatal cord blood cells

BACKGROUND

Vitamin C (ascorbic acid) is an essential water-soluble antioxidant in cells and plasma. Besides metabolic functions, vitamin C is also known to contribute to immune homeostasis. Recently, it has been demonstrated that vitamin C has an inhibitory effect on the expression of pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor alpha (TNF-alpha) in adult whole blood cells in vitro. It has been postulated that vitamin C might be an interesting compound for modulation of an over-exuberant immune response, e.g., in patient cohorts susceptible for the development of systemic inflammatory response syndrome such as neonates. It was the aim of this study to investigate the modulatory effects of vitamin C on the production of inflammatory mediators in neonatal cord blood cells.

METHODS

The intracytoplasmic production of pro-inflammatory cytokines in neonatal cord blood cells stimulated with lipopolysaccharide or phorbol 12-myristate 13-acetate/ionomycin was assessed by flow-cytometry.

RESULTS

In contrast to our previous observations from adult whole blood cells, 20 mM vitamin C mildly stimulated the percentage of neonatal monocytes producing IL-6 after lipopolysaccharide stimulation (e.g., 11.3% increase compared to control, p = 0.005). In the presence of 20 mM vitamin C, even a stronger stimulatory effect was noted for the percentage of IL-8 (e.g., 46.7% increase, p < 0.001) and TNF-alpha producing neonatal monocytes (e.g., 69.2% increase, p = 0.004; n = 20). In accordance with adult data, the percentage of neonatal lymphocytes producing IL-2 after phorbol 12-myristate 13-acetate/ionomycin stimulation was dose-dependently reduced (e.g., 41.3% inhibition, p = 0.001, 20 mM vitamin C), while the percentage of TNF-alpha producing lymphocytes was mildly stimulated (e.g., 20.8% increase, p = 0.003, 20 mM vitamin C).

CONCLUSIONS

Interestingly, vitamin C was demonstrated to enhance pro-inflammatory responses in CD14(+) cord blood cells while only intracellular IL-2 production in CD3(+) cells was diminished. These data suggest that vitamin C differentially influences intracytoplasmic cytokine production in adults and neonates, and further studies are needed to elucidate the underlying mechanisms of this selective immunomodulation.

Alleviation of oxidative and nitrosative stress following curative resection in patient with oral cavity cancer

BACKGROUND

Oxidative stress by reactive oxygen species (ROS) and nitrosative stress by reactive nitrogen species (RNS) are proven initiators and promoters in carcinogenesis. Elevated ROS/RNS with lowered antioxidants occur in patients with squamous cell carcinoma of oral cavity. Ours is the first study to evaluate the effect of curative resection on both oxidative and nitrosative stress in such patients.

METHODS

This study was conducted on 24 cancer patients and with age- and sex-matched healthy controls. Lipid peroxidation products, nitric oxide (NO) products and ceruloplasmin (CPL) in plasma were measured before and after surgery. Similarly enzymatic antioxidants in erythrocytes and non-enzymatic antioxidants in plasma were measured.

RESULTS

Statistically significant elevation of lipid peroxidation, NO products and CPL and depletion of antioxidants were found in cancer patients compared with controls. After curative surgical resection there was a statistically significant fall in oxidants and CPL coupled with a rise in antioxidants.

CONCLUSIONS

Our results suggest that oxidative/nitrosative stress could play a significant role in oral cavity cancer (OCC) and that curative resection is effective in alleviating this oxidative/nitrosative burden. Significant mitigation of oxidative/nitrosative stress could indicate the completeness of resection since tumor forms the major source of oxidants.

TFIIA plays a role in the response to oxidative stress

To characterize the role of the general transcription factor TFIIA in the regulation of gene expression by RNA polymerase II, we examined the transcriptional profiles of TFIIA mutants of Saccharomyces cerevisiae using DNA microarrays. Whole-genome expression profiles were determined for three different mutants with mutations in the gene coding for the small subunit of TFIIA, TOA2. Depending on the particular mutant strain, approximately 11 to 27% of the expressed genes exhibit altered message levels. A search for common motifs in the upstream regions of the pool of genes decreased in all three mutants yielded the binding site for Yap1, the transcription factor that regulates the response to oxidative stress. Consistent with a TFIIA-Yap1 connection, the TFIIA mutants are unable to grow under conditions that require the oxidative stress response. Underexpression of Yap1-regulated genes in the TFIIA mutant strains is not the result of decreased expression of Yap1 protein, since immunoblot analysis indicates similar amounts of Yap1 in the wild-type and mutant strains. In addition, intracellular localization studies indicate that both the wild-type and mutant strains localize Yap1 indistinguishably in response to oxidative stress. As such, the decrease in transcription of Yap1-dependent genes in the TFIIA mutant strains appears to reflect a compromised interaction between Yap1 and TFIIA. This hypothesis is supported by the observations that Yap1 and TFIIA interact both in vivo and in vitro. Taken together, these studies demonstrate a dependence of Yap1 on TFIIA function and highlight a new role for TFIIA in the cellular mechanism of defense against reactive oxygen species.

Enzymatic and non-enzymatic antioxidant status in stage (III) human oral squamous cell carcinoma and treated with radical radio therapy: influence of selenium supplementation

BACKGROUND

Oxidative stress is implicated in oral carcinogenesis and has been found to be aggravated during radiotherapy. A great deal of attention has been focused on the possible therapeutic implications of selenium as a potent antioxidant. We determined whether selenium supplementation to radiation treated oral cancer patients render improvement in the antioxidant status against oxidative stress.

METHOD

Blood samples were collected from stage (III) oral cancer patients before initiating radiotherapy (Group B) (n=63) and this group is bifurcated into Group C-patients given radiotherapy alone (n=27) and Group D-patients given radiotherapy and supplemented with selenium (400 mug/day for 6 months) (n=36). Both Group C and D were followed up for 6 months. We evaluated the plasma selenium concentration, non-enzymatic system including GSH, vitamins E, C, A and ceruloplasmin and enzymatic antioxidant system including superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase.

RESULTS

The concentrations of selenium, all non-enzymatic antioxidants and the activities of enzymatic antioxidants were found to be lowered in oral cancer patients (Group B), compared to normal (Group A) (p<0.05). Similar decrease in the concentration of selenium and antioxidants status was observed in radiotherapy group (Group C) (p<0.05). On the contrary, selenium group (Group D) showed marked increase in the concentrations of selenium and antioxidant status at 6 months compared to radiation group (Group C) (p<0.05).

CONCLUSION

The observed result represents the antioxidant property of selenium through the improvement of antioxidant defense system. Selenium supplementation could be of great interest in protecting cells against oxidative stress.

Antioxidant vitamins reduce oxidative stress and ventricular remodeling in patients with acute myocardial infarction

We analyzed soluble vascular adhesion molecules (sVCAM-1), reactive oxygen metabolites (ROMs) level, total antioxidant status (TAS) and telediastolic left ventricular volume (TLVV) in patients with myocardial infarction undergoing reperfusion therapy and treated with antioxidant vitamins (AT) or placebo (P) before and for 1 month after reperfusion. After reperfusion, sVCAM-1 serum concentration, reactive oxygen metabolites level, and TLVV were significantly higher in patients treated with placebo than in those treated with antioxidant vitamins, while TAS was significantly higher in patients treated with antioxidant supplementation. We observed that 48 hours after reperfusion sVCAM-1 (P) vs sVCAM-1 (AT) was 2.03+/-0.5 vs 1.63+/-0.7 microg/ml with p < 0.01; ROMs (P) vs ROMs (AT) were 335.60+/-35.80 vs 307.50+/-47.10 U.CARR with p < 0.05; TAS (P) vs TAS (AT) was 526.47+/-44.24 vs 737.65+/-51.15 micromol/l with p < 0.01; 1 week after reperfusion TLVV (P) vs TLVV (AT) was 125.12+/-29.80 vs 119.40+/-29.40 ml with p < 0.05; 1 month after reperfusion TLVV (P) vs TLVV (AV) was 132.00+/-33.50 vs 123.40+/-21.60 ml with p < 0.05. In the first period after infarction, vitamin treatment improves the antioxidant system and reduces oxidative stress, inflammatory process and left ventricular remodeling.

Oxidative stress parameters in bitches with mammary gland tumours

The aim of the present study was to describe some of the oxidative stress parameters in bitches suffering from spontaneously occurring mammary gland tumours. The experiment involved 28 bitches which had mammary gland tumours removed surgically (15 bitches with malignant tumour and 13 with benign tumour) as well as 10 clinically healthy bitches. The activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined in haemolysates of erythrocytes derived from the animals. The concentrations of thiobarbituric acid reactive substances (TBARS), as well as -SH groups, were determined in blood plasma. GSH-Px activity was significantly higher in the malignant tumour group than in healthy animals. SOD activity was significantly higher in animals with tumours compared with the control group. Activities of both enzymes were higher in animals with malignant tumours than in benign groups, but the differences were not statistically significant. The concentrations of TBARS and -SH groups were similar in all examined groups. The increase of antioxidative enzyme activities in these animals may suggest the activation of antioxidative defence mechanisms in mammary gland carcinogenesis. Moreover, it might indicate the participation of oxidative stress in malignancies. Further experiments involving more animals, with more frequent sample collection and the use of other oxidative stress markers are necessary.

Effects of conjugated linoleic acid on growth and cytokine expression in Jurkat T cells

Conjugated linoleic acid (CLA) has shown beneficial properties in animal models including anti-cancer, anti-atherogenic and anti-diabetic effects, while contrasting immunological effects were reported. While its anti-inflammatory activity has been associated to inhibition of arachidonic acid biosynthesis and to peroxisome proliferator-activated receptors (PPARs) activity, the molecular pathways underlying its immunoenhancing activity are essentially unknown. The aim of our study was to examine whether CLA showed specific effects in vitro on a T cell model, represented by the Jurkat cell line. CLA was found non toxic for Jurkat in the range 50-200 microM, as assessed by LDH release; however, incubation with 50 microM CLA was associated to a significant inhibitory effect on cell proliferation. The analysis of IL-2 and IFN-gamma transcript levels, produced in stimulated Jurkat cells, showed an increased expression of both cytokines in CLA-treated cells. Interestingly, the increased induction of IL-2 but not of IFN-gamma mRNA, could be suppressed by co-incubation with Gö 6976, a protein kinase C (PKC) inhibitor. Co-incubation with superoxide dismutase (SOD) or N-acetyl-L-cysteine (NAC) restored the basal levels of RNA synthesis for both cytokines. Taken together, these results suggest a specific role for dietary CLA in the modulation of the immune response in a T cell line model that is mediated, at least in part, by PKC and through the production of oxidative molecules.

Plasma membrane potential interferes with the respiratory burst of peripheral granulocytes

Membrane potential is involved in the regulation of several immune functions developed by granulocytes. The Na(+)/K(+) gradient across the plasma membrane, mainly generated by the Na(+)/K(+) pump, plays a key role in the maintenance of membrane potential. This study is focused on the correlation between plasma membrane potential and the in vitro receptor - triggered respiratory burst of normal human peripheral granulocytes. The respiratory burst was measured as superoxide anion release by the cytochrome c reduction test and plasma membrane potential was modulated by experimental changes of the extracellular potassium concentration. Results show a differentiated cellular response, depending on the in vivo activation state and on the signals received in vitro by granulocytes via CR3 or FcgammaR. Alteration of the membrane potassium gradient modulates the respiratory burst of unstimulated and CR3-activated cells, whilst it does not seem to significantly interfere with the signals delivered by FcgammaR.