Is vitamin C an antiinflammatory agent?

Dietary Compounds in the Prevention of Arsenic Induced Intestinal Toxicity In Vitro

Recent studies show that inorganic arsenic (As) exerts a toxic effect on the intestinal epithelium, causing a significant increase in its permeability. This disruption of the epithelial barrier may favor the entry of contaminants or toxins into the systemic circulation, thus causing toxicity not only at the intestinal level but possibly also at the systemic level. The present study conducts an in vitro evaluation of the protective effect of various dietary supplements and plant extracts against the intestinal toxicity of inorganic As. Some of these compounds were found to exert a protective effect. A significant decrease was observed in intracellular reactive oxygen/nitrogen species (10-31%), as well as a lower secretion of the pro-inflammatory cytokine IL-8 (25-41%) in the intestinal monolayers treated with the supplements and extracts, compared with those exposed only to As(III). The most effective supplements (glutathione/cysteine/vitamin C and lipoic acid) also normalized the distribution of tight junction protein zonula occludens-1, with partial restoration of the paracellular permeability and cell regeneration capacity of the intestinal epithelial cells. The results obtained show that dietary supplements and plant extracts can reduce the intestinal barrier disruption caused by inorganic As, and this may have a positive impact at both local and systemic levels.

Impact of thermal processing on polyphenols, carotenoids, glucosinolates, and ascorbic acid in fruit and vegetables and their cardiovascular benefits

Bioactive compounds in fruit and vegetables have a positive impact on human health by reducing oxidative stress, inflammation, and the risk of chronic diseases such as cancer, cardiovascular (CV) diseases, and metabolic disorders. However, some fruit and vegetables must be heated before consumption and thermal processes can modify the amount of nutraceuticals, that is, polyphenols, carotenoids, glucosinolates, and ascorbic acid, that can increase or decrease in relation to different factors such as type of processing, temperature, and time but also the plant part (e.g., flower, leaf, tuber, and root) utilized as food. Another important aspect is related to the bioaccessibility and bioavailability of nutraceuticals. Indeed, the key stage of nutraceutical bioefficiency is oral bioavailability, which involves the release of nutraceuticals from fruit and vegetables in gastrointestinal fluids, the solubilization of nutraceuticals and their interaction with other components of gastrointestinal fluids, the absorption of nutraceuticals by the epithelial layer, and the chemical and biochemical transformations into epithelial cells. Several studies have shown that thermal processing can enhance the absorption of nutraceuticals from fruit and vegetable. Once absorbed, they reach the blood vessels and promote multiple biological effects (e.g., antioxidant, anti-inflammatory, antihypertensive, vasoprotective, and cardioprotective). In this review, we described the impact of different thermal processes (such as boiling, steaming and superheated steaming, blanching, and microwaving) on the retention/degradation of bioactive compounds and their health-promoting effects after the intake. We then summarized the impact of heating on the absorption of nutraceuticals and the biological effects promoted by natural compounds in the CV system to provide a comprehensive overview of the potential impact of thermal processing on the CV benefits of fruit and vegetables.

Effects of swimming exercise combined with silymarin and vitamin C supplementation on hepatic inflammation, oxidative stress, and histopathology in elderly rats with high-fat diet-induced liver damage

OBJECTIVES

The aim of this study was to demonstrate that swimming exercise combined with silymarin and vitamin C supplementation improves hepatic inflammation, oxidative stress, and liver histopathology in elderly rats with high-fat diet-induced liver damage.

METHODS

Forty elderly male Wistar rats were randomly assigned to five groups (n = 8 in each): a normal diet (control), a high-fat diet (HFD), HFD + silymarin and vitamin C supplementation (HFD+Sup), HFD + swimming exercise (HFD+Exe), and HFD+Sup+Exe group (HFD+Sup+Exe). The non-alcoholic fatty liver model was induced for 6 wk in the HFD groups. After 6 wk of consuming an HFD, a daily supplemental gavage was administered to rats as an intervention along with HFD in the supplement groups for 8 wk. Moreover, rats in the exercise groups were subjected to swimming exercise training 5 d/wk for the same period.

RESULTS

The combination of swimming training and supplementation caused significant decreases in liver inflammatory biomarkers tumor necrosis factor-α and interleukin-1β while increasing total antioxidant capacity and peroxisome proliferator-activated receptor α (P < 0.05).

CONCLUSION

In elderly rats with liver injury caused by an HFD, the combination of exercise and silymarin with vitamin C supplementation effectively reduced oxidative stress, liver inflammation, fat accumulation, and regulated liver enzymes.

Antioxidative and Anti-Inflammatory Activity of Ascorbic Acid

Ascorbic acid, as a one of the basic exogenous vitamins, occurs in the body in the form of ascorbate, known for its strong antioxidant and anti-inflammatory properties. The presented review shows not only the importance of ascorbate as a free radical scavenger but also summarizes its antioxidant action based on other mechanisms, including the activation of intracellular antioxidant systems and its effect on the NFκB/TNFα pathway and apoptosis. Ascorbate interacts with small-molecule antioxidants, including tocopherol, glutathione, and thioredoxin; it can also stimulate biosynthesis and the activation of antioxidant enzymes, such as superoxide dismutase, catalase, or glutathione peroxidase. Moreover, ascorbate promotes the activity of transcription factors (Nrf2, Ref-1, AP-1), which enables the expression of genes encoding antioxidant proteins. Additionally, it supports the action of other exogenous antioxidants, mainly polyphenols. In this regard, both DNA, proteins, and lipids are protected against oxidation, leading to an inflammatory reaction and even cell death. Although ascorbate has strong antioxidant properties, it can also have pro-oxidant effects in the presence of free transition metals. However, its role in the prevention of DNA mutation, inflammation, and cell apoptosis, especially in relation to cancer cells, is controversial.

Newly synthesized chitosan-nanoparticles attenuate carbendazim hepatorenal toxicity in rats via activation of Nrf2/HO1 signalling pathway

Widespread application of carbendazim (CBZ) is a major environmental impact because of its residues that caused multi-organ dysfunction. Recently, Chitosan nanoparticles (CS-NPs) are extensively used as nanocarriers due to their non-toxic and biodegradable nature. Therefore, the current study aimed to investigate the possible mechanistic pathway of modified CS-NPs to reduce the hepatic and nephrotoxicity of CBZ in rats. CS-NPs were synthesized by the ionic gelation method by using ascorbic acid instead of acetic acid to increase its antioxidant efficiency. Twenty-adult male Wistar rats were grouped (n = 5) as follows: Group (1) negative control, group (2) received CS-NPs, group (3) received CBZ, and group (4) co-administered CS-NPs with CBZ. Rats received the aforementioned materials daily by oral gavage for 28 days and weighed weekly. The results revealed that CBZ receiving group showed severe histopathological alterations in the liver and kidney sections including cellular necrosis and interstitial inflammation confirmed by immunostaining and showed marked immunopositivity of iNOS and caspase-3 protein. There were marked elevations in the serum levels of ALT, AST, urea, and creatinine with a significant increase in MDA levels and decrease in TAC levels. Upregulation of the Keap1 gene and down-regulation of Nrf2 and HO-1 genes were also observed. Co-treatment of rats by CS-NPs with CBZ markedly improved all the above-mentioned toxicological parameters and return liver and kidney tissues to normal histological architecture. We concluded that CBZ caused hepatorenal toxicity via oxidative stress and the Nrf2/HO-1 pathway and CS-NPs could reduce CBZ toxicity via their antioxidant, anti-apoptotic, and anti-inflammatory effects.

Scurvy Masquerading as Juvenile Idiopathic Arthritis or Vasculitis with Elevated Inflammatory Markers: A Case Series

Ten patients with scurvy were evaluated by rheumatology; we review their clinical, laboratory, and dietary presentations. Eight patients had developmental delay or autism. All had elevated inflammatory markers. These clinical and laboratory features with imaging findings can mimic rheumatic conditions such as arthritis, vasculitis, and chronic nonbacterial osteomyelitis (CNO).

EFFECTS OF VITAMIN C SUPPLEMENTATION ON THE CHRONIC PHASE OF CHAGAS DISEASE

Introduction:

In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 10⁴ trypomastigotes of T. cruzi QM1strain.

Methods:

Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle.

Results:

Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever.

Conclusion:

Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory.

Effect of vitamin C on inflammation and metabolic markers in hypertensive and/or diabetic obese adults: a randomized controlled trial

BACKGROUND

Obesity is well associated as being an interfering factor in metabolic diseases such as hypertension and diabetes by increasing the secretion of proinflammatory markers from adipose tissue. Having healthy effects, vitamin C could work as an anti-inflammatory agent through its antioxidant capacity.

REGISTRATION

REGISTRATION NUMBER

FPSK_Mac [13]04.

OBJECTIVE

The aim of the study reported here was to identify the effect of vitamin C on reducing the levels of inflammatory markers in hypertensive and/or diabetic obese adults.

SUBJECTS AND METHODS

Sixty-four obese patients, who were hypertensive and/or diabetic and had high levels of inflammatory markers, from primary health care centers in Gaza City, Palestine, were enrolled into one of two groups in an open-label, parallel, randomized controlled trial. A total of 33 patients were randomized into a control group and 31 patients were randomized into an experimental group. The experimental group was treated with 500 mg vitamin C twice a day.

RESULTS

In the experimental group, vitamin C significantly reduced the levels of high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), fasting blood glucose (FBG), and triglyceride (TG) after 8 weeks of treatment (overall: P<0.001); no changes appeared in total cholesterol (TC). In the control group, there were significant reductions in FBG and TG (P=0.001 and P=0.026, respectively), and no changes in hs-CRP, IL-6, or TC. On comparing the changes in the experimental group with those in the control group at the endpoint, vitamin C was found to have achieved clinical significance in treating effectiveness for reducing hs-CRP, IL-6, and FBG levels (P=0.01, P=0.001, and P<0.001, respectively), but no significant changes in TC or TG were found.

CONCLUSION

Vitamin C (500 mg twice daily) has potential effects in alleviating inflammatory status by reducing hs-CRP, IL-6, and FBG in hypertensive and/or diabetic obese patients.

Vitamin C exerts beneficial hepatoprotection against Concanavalin A-induced immunological hepatic injury in mice through inhibition of NF-κB signal pathway

The present study was designed to investigate the potential benefits of vitamin C (VC) in treating immunological liver injury induced by Concanavalin A (Con A, 20 mg kg(-1)) in mice. Interestingly, VC administration significantly reduced serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total-bilirubin (T-bilirubin) in Con A-lesioned mice, while serum concentrations of albumin and total-protein (T-protein) were increased. Moreover, inflammatory cytokine profiles, such as interferon-gamma (IFN-γ), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-8 (IL-8), were decreased in liver tissue by VC administration. Morphological examination showed that Con A-induced liver damage was effectively mitigated. As shown in RT-PCR assay, VC administration resulted in down-regulated mRNA expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). In addition, VC contributed towards the reduction of intrahepatic tumor necrosis factor alpha (TNF-α) and the receptor (TNF-R) protein levels, as well as decreasing IKKβ, p-IκBα, p50 and NF-κB expressions; furthermore, VC blocked intranuclear DNA-binding NF-κB locus. Our findings show that VC effectively attenuates Con A-mediated immunotoxicity in liver tissue, through an underlying mechanism which relates to dampening of the intrahepatic NF-κB signal pathway, thereby reducing cytotoxicity within hepatocytes.

Atherosclerosis and oxidant stress: the end of the road for antioxidant vitamin treatment?

Extensive experimental data have revealed a central role for oxidative stress in atherogenesis and suggested a potential role for 'antioxidant' treatment in cardiovascular disease (CVD) [1-11]. Experimental data, however, have not translated into clinical benefit: most antioxidant vitamin trials have failed to reduce cardiovascular morbidity and mortality [12]. Moreover, recent clinical trials have suggested that mono-therapy with certain antioxidant vitamins like vitamin E may, in fact, be detrimental [13]. As a result of the disappointing outcome of 'antioxidant' vitamin trials, some authors have questioned both the utility of 'antioxidant' treatment in CVD and the supposedly central role of oxidative stress in atherogenesis [14-19]. Other investigators, however, sustain that the beneficial effects of lipid lowering and anti-hypertensive treatment are at least, in part, due to their 'antioxidant' properties, in addition to their specific pharmacological properties [20, 21]. Oxidant stress plays a pivotal role in atherogenesis, however, the clinical promise of antioxidant vitamins has failed to translate into clinical benefit. Increasing evidence suggests that more rigorous clinical trial designs are necessary to effectively divulge antioxidant utility and that a multifaceted antioxidant approach to atherosclerosis may yield the most clinical reward. This article reviews currently available evidence on the role of oxidant stress in atherosclerosis, analyzes the results of large anti-oxidant trials, and suggests ways to investigate the true role of antioxidant treatment in the clinical setting.

Contribution of selected vitamins and trace elements to immune function

Adequate intakes of vitamins and trace elements are required for the immune system to function efficiently. Micronutrient deficiency suppresses immune functions by affecting the innate T-cell-mediated immune response and adaptive antibody response, and leads to dysregulation of the balanced host response. This increases the susceptibility to infections, with increased morbidity and mortality. In turn, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Insufficient intake of micronutrients occurs in people with eating disorders, in smokers (both active and passive), in individuals with chronic alcohol abuse, in patients with certain diseases, during pregnancy and lactation, and in the elderly. With aging a variety of changes are observed in the immune system, which translate into less effective innate and adaptive immune responses and increased susceptibility to infections. Antioxidant vitamins and trace elements (vitamins C, E, selenium, copper, and zinc) counteract potential damage caused by reactive oxygen species to cellular tissues and modulate immune cell function through regulation of redox-sensitive transcription factors and affect production of cytokines and prostaglandins. Adequate intake of vitamins B(6), folate, B(12), C, E, and of selenium, zinc, copper, and iron supports a Th1 cytokine-mediated immune response with sufficient production of proinflammatory cytokines, which maintains an effective immune response and avoids a shift to an anti-inflammatory Th2 cell-mediated immune response and an increased risk of extracellular infections. Supplementation with these micronutrients reverses the Th2 cell-mediated immune response to a proinflammatory Th1 cytokine-regulated response with enhanced innate immunity. Vitamins A and D play important roles in both cell-mediated and humoral antibody response and support a Th2-mediated anti-inflammatory cytokine profile. Vitamin A deficiency impairs both innate immunity (mucosal epithelial regeneration) and adaptive immune response to infection resulting in an impaired ability to counteract extracellular pathogens. Vitamin D deficiency is correlated with a higher susceptibility to infections due to impaired localized innate immunity and defects in antigen-specific cellular immune response. Overall, inadequate intake and status of these vitamins and minerals may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition.