Different doses of vitamin C supplementation enhances the Th1 immune response to early Plasmodium yoelii 17XL infection in BALB/c mice

The roles of vitamin C in infectious diseases: A comprehensive review

Vitamin C is a versatile nutrient with essential antioxidant properties and roles in amino acid metabolism, collagen promotion, and hormone synthesis. It has long been regarded as benefitting infectious disease management, although its specific roles remain uncertain. The dominant view is that this efficacy not only stems from its redox regulation in the body but also from its profound impact on the immune system. This review provides a comprehensive overview of Vitamin C's effects on redox regulation and shows how the vitamin influences various immune cells and cell-intrinsic innate immunity signaling pathways, thereby updating and expanding our previous perspectives. Clinically, though some studies and case series have suggested potential benefits of Vitamin C in preventing and (or) treating respiratory tract infections and sepsis and septic shock, the evidence remains controversial. The current data is insufficient to support the routine clinical use of Vitamin C in managing these diseases and requires further rigorous evaluation to establish definitive efficacy and safety profiles. This review thoroughly examines current clinical research progress on Vitamin C, summarizes the primary controversies and their underlying causes, and proposes directions for future clinical research. Furthermore, preclinical evidence shows potential roles for Vitamin C in the supplementary treatment of the "Big Three" infectious diseases: acquired immunodeficiency syndrome (AIDS), tuberculosis, and malaria; however, systematic clinical studies in these areas are lacking. We examine related in vitro and animal studies, as well as clinical trials, and discuss potential roles for Vitamin C as a treatment and (or) adjuvant therapy.

Plasmodium Infection Modulates Host Inflammatory Response through circRNAs during the Intracellular Stage in Red Blood Cells

The integration of RNA- and DNA-based assays enables the investigation of disease dynamics, specifically assessing the role of asymptomatic or subclinical infections in malaria transmission. Circular RNAs (circRNAs), a distinct category of noncoding RNAs, are implicated in numerous pathogenic mechanisms. As of now, research has yet to explore circRNAs' function in malaria infection. The findings revealed that Plasmodium infection upregulated 60 circRNAs and downregulated 71 in BALB/c mice. We selected 11 differentially expressed (DE) circRNAs according to function prediction of target miRNA-mRNA and coding protein, and these were further confirmed by validation experiments. IRESfinder, GO, and KEGG evaluations indicated that 7 DE circRNAs possess protein-coding potential and are enriched in the MAPK signaling cascade. In P.y17XL-infected BALB/c mouse models, the findings substantiated that the dynamic characteristics of DE circRNAs correlated with inflammation, and the MAPK and NF-κB signaling cascades were activated, also contributing to the inflammatory reaction during malaria infection. This study establishes Plasmodium-induced circRNA expression as a novel mechanism by which the parasite modulates host immune signaling, advancing the understanding of Plasmodium-host cell interactions. In addition, 42 circRNAs were found in normal BALB/c mice, and 25 circRNAs were discovered in P.y17XL-infected BALB/c mice, excluding 1238 circRNAs shared by normal and P.y17XL-infected BALB/c mice. Plasmodium infection changes the expression profile of circRNAs in the host, and these altered circRNAs are involved in the inflammatory response during malaria infection. In addition, Plasmodium possibly regulates the reverse splicing of pre-mRNA or m6A modification of RNA, inducing the production of novel circRNAs in the host.

Vitamin C variation in citrus in response to genotypes, storage temperatures, and storage times: A systematic review and meta-analysis

Numerous published studies have highlighted discrepancies in the duration and storage temperature used for preserving vitamin C content on various citrus genotypes worldwide. The present study aimed to analyze the variation in vitamin C content as influenced by citrus genotype, duration, and storage temperature using meta-analysis approaches. Data searching, selection, and tabulation resulted in a comprehensive database constructed from 1412 data points gathered from 54 individual studies, following PRISMA-P guidelines. The vitamin C content varied widely, ranging from 0 to 76.2 mg/100 mL in whole data of citrus fruit. Meta-analysis findings revealed that the duration of storage significantly impacted the vitamin C content in citrus fruits. Specifically, for grapefruit, mandarin, and orange, the length of storage significantly influenced their vitamin C levels (P < 0.01), with a consistent decrease observed over time. The correlation coefficients (R2) were 0.63 for grapefruit, 0.9 for mandarin, and 0.69 for orange. In contrast, no significant difference was found in terms of vitamin C levels between hybrid and lime citrus concerning the impact of storage time. However, other results indicated a significant influence of storage temperature on the variation in vitamin C levels for both citrus and hybrid varieties (P < 0.001). Depending on the genotype, tangerine had significantly lower vitamin C content compared to other varieties, at 16.9 mg/100 mL, with vitamin C ranging from 13.2 to 20.9 mg/100 mL (P < 0.001). The highest vitamin C content was found in lemon and hybrid varieties, around 65.5 (range 59.3-76.2) and 48.3 (range 29.6-75.5), respectively, all in mg/100 mL (P < 0.001). Furthermore, there was a tendency for decreasing vitamin C concentration due to temperature (P = 0.078), while citrus variety experienced a decrease, although not significant. The ideal temperature (15 °C) and duration of storage (56 days) to minimize vitamin C loss in citrus fruits are at their optimum point. In conclusion, the deterioration of vitamin C in citrus fruits is influenced by both temperature and storage duration, and its content is also impacted by the variety of citrus.

Ascorbic acid modulates immune responses through Jumonji-C domain containing histone demethylases and Ten eleven translocation (TET) methylcytosine dioxygenase

Ascorbic acid is a redox regulator in many physiological processes. Besides its antioxidant activity, many intriguing functions of ascorbic acid in the expression of immunoregulatory genes have been suggested. Ascorbic acid acts as a co-factor for the Fe+2 -containing α-ketoglutarate-dependent Jumonji-C domain-containing histone demethylases (JHDM) and Ten eleven translocation (TET) methylcytosine dioxygenasemediated epigenetic modulation. By influencing JHDM and TET, ascorbic acid facilitates the differentiation of double negative (CD4- CD8- ) T cells to double positive (CD4+ CD8+ ) T cells and of T-helper cells to different effector subsets. Ascorbic acid modulates plasma cell differentiation and promotes early differentiation of hematopoietic stem cells (HSCs) to NK cells. These findings indicate that ascorbic acid plays a significant role in regulating both innate and adaptive immune cells, opening up new research areas in Immunonutrition. Being a water-soluble vitamin and a safe micro-nutrient, ascorbic acid can be used as an adjunct therapy for many disorders of the immune system.

An outlook on the target-based molecular mechanism of phytoconstituents as immunomodulators

The immune system is one of the essential defense mechanisms. Immune system inadequacy increases the risk of infections and cancer diseases, whereas over-activation of the immune system causes allergies or autoimmune disorders. Immunomodulators have been used in the treatment of immune-related diseases. There is growing interest in using herbal medicines as multicomponent agents to modulate the complex immune system in immune-related diseases. Many therapeutic phytochemicals showed immunomodulatory effects by various mechanisms. This mechanism includes stimulation of lymphoid cell, phagocytosis, macrophage, and cellular immune function enhancement. In addition increased antigen-specific immunoglobulin production, total white cell count, and inhibition of TNF-α, IFN-γ, NF-kB, IL-2, IL-6, IL-1β, and other cytokines that influenced the immune system. This review aims to overview, widely investigated plant-derived phytoconstituents by targeting cells to modulate cellular and humoral immunity in in vivo and in vitro. However, further high-quality research is needed to confirm the clinical efficacy of plant-based immunomodulators.

Plasmodium manipulates the expression of host long non-coding RNA during red blood cell intracellular infection

BACKGROUND

Parasites interact with their host through "direct" and/or "indirect" mechanisms. Plasmodium, for example, either mediates direct physical interactions with host factors or triggers the immune system of the host indirectly, leading to changes in infectious outcomes. Long non-coding RNAs (lncRNAs) participate in regulating biological processes, especially host-pathogen interactions. However, research on the role of host lncRNAs during Plasmodium infection is limited.

METHODS

A RNA sequencing method (RNA-seq) was used to confirm the differential expression profiles of lncRNAs in Plasmodium yeolii 17XL (P.y17XL)-infected BALB/c mice. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to elucidate the potential functions of Plasmodium-induced genes. Subsequently, the effect of specific lncRNAs on the modulation of immune-related signaling pathways in malaria was determined by fluorescence-activated cell sorting, western blot and enzyme-linked immunosorbent assay.

RESULTS

The data showed that in P.y17XL-infected BALB/c mice, Plasmodium upregulated the expression of 132 lncRNAs and downregulated the expression of 159 lncRNAs. Differentially expressed lncRNAs clearly associated with malaria infection were annotated, including four novel dominant lncRNAs: ENMSUSG00000111521.1, XLOC_038009, XLOC_058629 and XLOC_065676. GO and KEGG pathway analyses demonstrated that these four differentially expressed lncRNAs were associated with co-localized/co-expressed protein-coding genes that were totally enriched in malaria and with the transforming growth factor beta (TGF-β) signaling pathway. Using the models of P.y17XL-infected BALB/c mice, data certified that the level of TGF-β production and activation of TGF-β/Smad_2/3 signaling pathway were obviously changed in malaria infection.

CONCLUSIONS

These differentially expressed immune-related genes were deemed to have a role in the process of Plasmodium infection in the host via dendritic/T regulatory cells and the TGF-β/Smad_2/3 signaling pathway. The results of the present study confirmed that Plasmodium infection-induced lncRNA expression is a novel mechanism used by Plasmodium parasites to modify host immune signaling. These results further enhance current understanding of the interaction between Plasmodium and host cells.

Oxidative Stress in Malaria: Potential Benefits of Antioxidant Therapy

Malaria is an infectious disease and a serious public health problem in the world, with 3.3 billion people in endemic areas in 100 countries and about 200 million new cases each year, resulting in almost 1 million deaths in 2018. Although studies look for strategies to eradicate malaria, it is necessary to know more about its pathophysiology to understand the underlying mechanisms involved, particularly the redox balance, to guarantee success in combating this disease. In this review, we addressed the involvement of oxidative stress in malaria and the potential benefits of antioxidant supplementation as an adjuvant antimalarial therapy.

Effect of giving probiotic supplement Lactobacillus acidophilus La-14 as an immunomodulator to maintain a respiratory system in Mus musculus

Background and Objectives:

In 2020 the whole world is experiencing a pandemic condition due to infection with the SARS-CoV-2 virus which can cause the COVID-19 disease. This condition results in “Panic Buying”, because everyone tries to avoid the spread and transmission of the COVID-19 disease by doing various ways, one of which is by taking additional supplements such as vitamin C and probiotic supplements.

Materials and Methods:

The materials used were mice Mus musculus male DDY strain aged 1–2 months. Probiotic supplement Lactobacillus acidophilus La-14 with a viability of 1 × 10⁸ CFU/ml. with a weight of 0.16 grams dissolved in 0.25 ml 0.9% NaCl. Vitamin C used is a commercial vitamin C tablet, weighing 0.06 grams in 0.25 ml 0.9% NaCl. Meanwhile, the feed for mice (Mus musculus) is a complete feed from Pokphand with the code BR1 CP511B. Lung histology preparations data were analysed descriptively and statistically through the test Chi square while the data on the number of lymphocytes were analysed descriptively.

Results:

The histological observations of lungs of Mus musculus showed that in the treatment of ML, MV, and MKA test was carried out chi square ratio between the groups that did not have lymphocyte infiltration and those that had lymphocyte infiltration showed a significant difference (p <0.05). Meanwhile, the results of the lymphocyte count showed that ML and MV treatment was higher than that of MK treatment.

Conclusion:

It is suggested that the administration of probiotics can stimulate and modulate the respiratory immune system.

Differential Effect of Antioxidants Glutathione and Vitamin C on the Hepatic Injuries Induced by Plasmodium berghei ANKA Infection

Malaria is a life-threatening disease caused by Plasmodium and represents one of the main public health problems in the world. Among alterations associated with the disease, we highlight the hepatic impairment resulting from the generation of oxidative stress. Studies demonstrate that liver injuries caused by Plasmodium infection are associated with unbalance of the antioxidant system in hepatocytes, although little is known about the role of antioxidant molecules such as glutathione and vitamin C in the evolution of the disease and in the liver injury. To evaluate disease complications, murine models emerge as a valuable tool due to their similarities between the infectious species for human and mice. Herein, the aim of this study is to evaluate the effect of antioxidants glutathione and vitamin C on the evolution of murine malaria and in the liver damage caused by Plasmodium berghei ANKA infection. Mice were inoculated with parasitized erythrocytes and treated with glutathione and vitamin C, separately, both at 8 mg/kg during 7 consecutive days. Our data showed that during Plasmodium infection, treatment with glutathione promoted significant decrease in the survival of infected mice, accelerating the disease severity. However, treatment with vitamin C promoted an improvement in the clinical outcomes and prolonged the survival curve of infected animals. We also showed that glutathione promoted increase in the parasitemia rate of Plasmodium-infected animals, although treatment with vitamin C has induced significant decrease in parasitemia rates. Furthermore, histological analysis and enzyme biochemical measurement showed that treatment with glutathione exacerbates liver damage while treatment with vitamin C mitigates the hepatic injury induced by the infection. In summary, the current study provided evidences that antioxidant molecules could differently modulate the outcome of malaria disease; while glutathione aggravated the disease outcome and liver injury, the treatment with vitamin C protects the liver from damage and the evolution of the condition.

Low level of Vitamin C and dysregulation of Vitamin C transporter might be involved in the severity of COVID-19 Infection

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been spreading around the world at an exponential pace, leading to millions of individuals developing the associated disease called COVID-19. Due to the novel nature and the lack of immunity within humans, there has been a collective global effort to find effective treatments against the virus. This has led the scientific community to repurpose Food and Drug Administration (FDA) approved drugs with known safety profiles. Of the many possible drugs, vitamin C has been on the shortlist of possible interventions due to its beneficial role as an immune booster and inherent antioxidant properties. Within this manuscript, a detailed discussion regarding the intracellular function and inherent properties of vitamin C is conducted. It also provides a comprehensive review of published research pertaining to the differences in expression of the vitamin C transporter under several pathophysiologic conditions. Finally, we review recently published research investigating the efficacy of vitamin C administration in treating viral infection and life-threatening conditions. Overall, this manuscript aims to present existing information regarding the extent to which vitamin C can be an effective treatment for COVID-19 and possible explanations as to why it may work in some individuals but not in others.

Elimination of Hepatic Rodent Plasmodium Parasites by Amino Acid Supplementation

Plasmodium parasites, causative agents of malaria, scavenge host nutrients to sustain their intracellular replication. Modulation of the host's nutritional status can potentially help control infection by limiting the parasite's access to nutrients, or by boosting the immune system. Here, we show that dietary supplementation of mice employing a combination of arginine (R) with two additional amino acids, lysine (K) and valine (V), termed RKV, significantly decreases Plasmodium liver infection. RKV supplementation results in the elimination of parasites at a late stage of their development in the liver. Our data employing genetic knockout mouse models and in vivo depletion of specific cell populations suggest that RKV supplementation boosts the host's overall innate immune response, and that parasite elimination is dependent on MyD88 signaling in immune cells. The immunostimulatory effect of RKV supplementation opens a potential role for dietary supplementation as an adjuvant for prophylaxis or immunization strategies against Plasmodium infection.

Modulation of anti-malaria immunity by vitamin A in C57BL/6J mice infected with heterogenic plasmodium

Vitamin A (VA) is an anti-inflammatory agent that is important in modulating and balancing the immune system. The present study aimed to investigate the immunoregulatory effects of vitamin A supplement (VAS) in C57BL/6J mice infected with Plasmodium yoelii 17XL (P.y17XL) or Plasmodium berghei ANKA (P.bANKA). Following VA treatment, parasitaemia decreased, but survival rate did not significantly change during P.y17XL infection. However, in P.bANKA infected C57BL/6J mice, VA pretreatment decreased parasitaemia, and a lag in cerebral malaria (CM) was observed during the early stages of infection. Furthermore, VA pretreatment was also demonstrated to upregulate MHCII expression in dendritic cells (DCs), downregulate Th1 and Tregs, and downregulate TNF-α and IFN-γ production. The results of the current study indicated that VAS downregulated the inflammation response in CM, but did not exhibit an immunoregulatory effect against P.y17XL infection. VAS protected the onset of CM by reducing inflammation, and was also correlated with the downregulation of Th1 by modifying the function of DCs and Tregs. However, no significant effect was observed during P.y17XL infection.

Immunomodulatory and Antimicrobial Effects of Vitamin C

Humans have lost their vitamin C-synthesizing capacities during evolution. Therefore, the uptake of this essential compound from external sources is mandatory in order to prevent vitamin C-deficient conditions resulting in severe morbidities such as scurvy. The potent antioxidant, immunomodulatory, and antiinfectious effects of vitamin C are known since the 1930s. We here (i) review the impact of vitamin C on innate and adaptive immune functions, (ii) provide an overview of its antimicrobial, antibacterial, antiviral, antiparasitic, and antifungal properties, and finally, (iii) discuss vitamin C as an adjunct treatment option for the combat of human infections by bacteria, particularly by emerging multidrug-resistant species.