Effects of supplemental β-carotene on mucosal IgA induction in the jejunum and ileum of mice after weaning

Probiotics induce intestinal IgA secretion in weanling mice potentially through promoting intestinal APRIL expression and modulating the gut microbiota composition

Intestinal infections are strongly associated with infant mortality, and intestinal immunoglobulin A (IgA) is important to protect infants from intestinal infections after weaning. This study aims to screen probiotics that can promote the production of intestinal IgA after weaning and further explore their potential mechanisms of action. In this study, probiotics promoting intestinal IgA production were screened in weanling mouse models. The results showed that oral administration of Bifidobacterium bifidum (B. bifidum) FL228.1 and Bifidobacterium bifidum (B. bifidum) FL276.1 significantly enhanced IgA levels in the small intestine and upregulated the expression of a proliferation-inducing ligand (APRIL) and its upstream regulatory factor toll-like receptor 4 (TLR4). Furthermore, B. bifidum FL228.1 upregulated the relative abundance of Lactobacillus, while B. bifidum FL276.1 increased the relative abundance of Marvinbryantia and decreased Mucispirillum, further elevating intestinal IgA levels. In summary, B. bifidum FL228.1 and B. bifidum FL276.1 can induce IgA production in the intestinal tract of weanling mice by promoting intestinal APRIL expression and mediating changes in the gut microbiota, thus playing a significant role in enhancing local intestinal immunity in infants.

Carotenoids and Their Health Benefits as Derived via Their Interactions with Gut Microbiota

Carotenoids have been related to a number of health benefits. Their dietary intake and circulating levels have been associated with a reduced incidence of obesity, diabetes, certain types of cancer, and even lower total mortality. Their potential interaction with the gut microbiota (GM) has been generally overlooked but may be of relevance, as carotenoids largely bypass absorption in the small intestine and are passed on to the colon, where they appear to be in part degraded into unknown metabolites. These may include apo-carotenoids that may have biological effects because of higher aqueous solubility and higher electrophilicity that could better target transcription factors, i.e., NF-κB, PPARγ, and RAR/RXRs. If absorbed in the colon, they could have both local and systemic effects. Certain microbes that may be supplemented were also reported to produce carotenoids in the colon. Although some bactericidal aspects of carotenoids have been shown in vitro, a few studies have also demonstrated a prebiotic-like effect, resulting in bacterial shifts with health-associated properties. Also, stimulation of IgA could play a role in this respect. Carotenoids may further contribute to mucosal and gut barrier health, such as stabilizing tight junctions. This review highlights potential gut-related health-beneficial effects of carotenoids and emphasizes the current research gaps regarding carotenoid-GM interactions.

β-carotene improves fecal dysbiosis and intestinal dysfunctions in a mouse model of vitamin A deficiency

Vitamin A deficiency (VAD) results in intestinal inflammation, increased redox stress and reactive oxygen species (ROS) levels, imbalanced inflammatory and immunomodulatory cytokines, compromised barrier function, and perturbations of the gut microbiome. To combat VAD dietary interventions with β-carotene, the most abundant precursor of vitamin A, are recommended. However, the impact of β-carotene on intestinal health during VAD has not been fully clarified, especially regarding the VAD-associated intestinal dysbiosis. Here we addressed this question by using Lrat^-/-Rbp^-/- (vitamin A deficient) mice deprived of dietary preformed vitamin A and supplemented with β-carotene as the sole source of the vitamin, alongside with WT (vitamin A sufficient) mice. We found that dietary β-carotene impacted intestinal vitamin A status, barrier integrity and inflammation in both WT and Lrat^-/-Rbp^-/- (vitamin A deficient) mice on the vitamin A-free diet. However, it did so to a greater extent under overt VAD. Dietary β-carotene also modified the taxonomic profile of the fecal microbiome, but only under VAD. Given the similarity of the VAD-associated intestinal phenotypes with those of several other disorders of the gut, collectively known as Inflammatory Bowel Disease (IBD) Syndrome, these findings are broadly relevant to the effort of developing diet-based intervention strategies to ameliorate intestinal pathological conditions.

Beta-carotene and its protective effect on gastric cancer

Beta-carotene is an important natural pigment that is very beneficial to human health. It is widely found in vegetables and fruits. The three main functions are antioxidant effects, cell gap junction-related functions and immune-related functions. Because of its diverse functions, beta-carotene is believed to prevent and treat many chronic diseases. Gastric cancer is one of the most important diseases it can treat. Gastric cancer is a type of cancer with a high incidence. Its etiology varies, and the pathogenesis is complex. Gastric cancer seriously affects human health. The role of beta-carotene, a natural nutrient, in gastric cancer has been explored by many researchers, including molecular mechanisms and epidemiological studies. Molecular studies have mainly focused on oxidative stress, cell cycle, signal transduction pathways and immune-related mechanisms of beta-carotene in gastric cancer. Many epidemiological surveys and cohort studies of patients with gastric cancer have been conducted, and the results of these epidemiological studies vary due to the use of different research methods and analysis of different regions. This paper will summarize the results of these studies, mainly in terms of molecular mechanisms and epidemiological research results, which will provide a systematic basis for future studies of the treatment and prognosis of gastric cancer. This paper will help researchers identify new research directions.

Gut microbiota regulation and anti-inflammatory effect of β-carotene in dextran sulfate sodium-stimulated ulcerative colitis in rats

β-Carotene displays antioxidant and anti-inflammatory activities and prevents the development of cancer. Ulcerative colitis (UC) is a kind of inflammatory bowel disease that is accompanied by a certain risk of colon cancer. However, the role of β-carotene in the modulation of gut microbiota and UC improvement is unclear. In this research, the properties of β-carotene on anti-inflammatory and the composition of gut microbiota were evaluated in a rat model of UC induced by dextran sulfate sodium (DSS). The results revealed that β-carotene significantly (p < 0.05) decreased the severity of colitis in rats, as assessed using body weight (6.00 ± 1.73%), colon length (22.23 ± 0.53%), and disease activity index, and improved the structure of the colon damaged. Moreover, colonic levels of proinflammatory cytokines were significantly lower following β-carotene supplementation. β-Carotene intervention also lowered the expression levels of phosphorylated p65 (0.60 ± 0.02), p38 (0.57 ± 0.00), Erk (0.63 ± 0.04), and JNK (0.70 ± 0.00). The result of the relative abundance of gut microbiota showed that DSS administration significantly changed the microbial structure at the phylum and genus levels of rats. Furthermore, β-carotene treatment significantly increased the abundance of Faecalibacterium, the levels of which negatively correlated with the levels of inflammatory cytokines. Faecalibacterium may be a potential target in the alleviation of DSS-induced UC. β-Carotene can alleviate DSS-induced UC through the regulation of gut microbiota. This study provides a reference for the rational use of β-carotene in the treatment of UC. PRACTICAL APPLICATION: β-Carotene can relieve ulcerative colitis and regulate the gut microbiota; the nutritional intervention of β-carotene enhancing animal health.

Rutin, α-tocopherol, and l-ascorbic acid up-regulate type I interferon-regulated gene and type I and II interferon expressions and reduce inflammatory cytokine expressions in monocyte-derived macrophages infected with highly pathogenic porcine reproductive and respiratory syndrome virus

This study evaluated the immunomodulatory effect of two types of phytochemicals, i.e. rutin and β-carotene, and two types of vitamins, i.e. α-tocopherol and l-ascorbic acid on improving innate immune responses to highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV). Monocyte-derived macrophages (MDM) from eight PRRSV-seronegative pigs were inoculated with HP-PRRSV and subsequently stimulated with rutin, β-carotene, α-tocopherol, and l-ascorbic acid in the absence or presence of either polyinosinic:polycytidylic acid or lipopolysaccharide. The mRNA expression levels of myxovirus resistance 1, interferon regulatory factor 3 (IRF3), IRF7, 2'-5'-oligoadenylatesynthetase 1, stimulator of interferon genes (STING), osteopontin (OPN), interferon alpha (IFNα), IFNβ, IFNγ, interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), and transforming growth factor beta (TGFβ) were evaluated by real-time PCR. Compared with control MDM, HP-PRRSV significantly suppressed mRNA expressions of all immune-related genes except IL-10 and TGFβ. Compared with HP-PRRSV-inoculated MDM, stimulation with rutin, α-tocopherol, and l-ascorbic acid, but not β-carotene significantly enhanced mRNA expression levels of IRF3, IRF7, STING, OPN, IFNα, IFNβ, and IFNγ in HP-PRRSV-inoculated MDM. Stimulation with rutin also significantly reduced mRNA expression levels of TNFα and TGFβ, whereas stimulation with β-carotene and α-tocopherol significantly reduced TNFα mRNA expression in HP-PRRSV-inoculated MDM. Our findings demonstrate the potentials of rutin, α-tocopherol, and l-ascorbic acid in enhancing type I interferon-regulated genes and type I and II IFN expressions, and in reducing pro- and/or anti-inflammatory cytokine expressions in HP-PRRSV-inoculated MDM. Our findings suggest that rutin, α-tocopherol, and l-ascorbic acid may serve as effective immunomodulators for improving innate immune response to HP-PRRSV.

Effects of supplementation with β-carotene on the growth performance and intestinal mucosal barriers in layer-type cockerels

β-carotene is a robust modulator of mucosal barriers, and it can amplify the immunoglobulin A (IgA) response via the retinoic acid (RA)-mediated pathway. We investigated the influence of β-carotene on intestinal barriers in layer-type cockerels. In this study, β-carotene has a positive influence on growth performance and intestinal morphology. β-carotene remarkably enhanced serum secretory immunoglobulin A (sIgA) levels, jejunal mucosal sIgA, and IgA concentrations. β-Carotene significantly enhanced mRNA expression levels of IgA, CC chemokine receptor-9 (CCR9), polymeric immunoglobulin receptor (pIgR), and retinoic acid receptor α (RARα) in the ileal tissues and pIgR in the jejunal tissues. β-Carotene improves mRNA expression of intestinal barrier-related proteins including: mucin-2 (MUC-2), zonula occludens-2 (ZO-2), occludins (OCLN), and zonula occludens-1 (ZO-1) in the ileal tissues. Moreover, β-carotene decreased the levels of Escherichia coli and elevates the levels of Lactobacillus. The results indicate that β-carotene can promote growth performance and contribute to the gradual development of intestinal barriers in Hyline Brown chicks. This study enriches our knowledge about the effects of β-carotene on intestinal barrier and highlights a theoretical basis of β-carotene application in the poultry industry.

β-Carotene prevents weaning-induced intestinal inflammation by modulating gut microbiota in piglets

Objective

Weaning is an important stage in the life of young mammals, which is associated with intestinal inflammation, gut microbiota disorders, and even death. β-Carotene displays anti-inflammatory and antioxidant activities, which can prevent the development of inflammatory diseases. However, whether β-carotene can affect intestinal microbiota remains unclear.

Methods

Twenty-four piglets were distributed into four groups: the normal suckling group (Con), the weaning group (WG), the weaning+β-carotene (40 mg/kg) group (LCBC), and the weaning+β-carotene (80 mg/kg) group (HCBC). The serum, jejunum, colon, and faeces were collected separately from each group. The effects of β-carotene on the phenotype, overall structure, and composition of gut microbiota were assessed in weaning piglets.

Results

The results showed that β-carotene improved the growth performance, intestinal morphology and relieved inflammation. Furthermore, β-carotene significantly decreased the species from phyla Bacteroidetes and the genus Prevotella, and Blautia, and increased the species from the phyla Firmicutes and the genera p-75-a5, and Parabacteroides compared to the WG group. Spearman’s correlation analysis showed that Prevotella and Blautia were positively correlated, and Parabacteroides and Synergistes were negatively correlated with the levels of interleukin-1β (IL-1β), IL-6, and tumour necrosis factor-α (TNF-α), while p-75-a5 showed negative correlation with IL-6 in serum samples from piglets.

Conclusion

These findings indicate that β-carotene could alleviate weaning-induced intestinal inflammation by modulating gut microbiota in piglets. Prevotella may be a potential target of β-carotene in alleviating the weaning-induced intestinal inflammation in piglets.

β-carotene attenuates weaning-induced apoptosis via inhibition of PERK-CHOP and IRE1-JNK/p38 MAPK signalling pathways in piglet jejunum

Weaning may cause oxidative injury, immune response impairment, apoptosis and other injuries in piglets. Oxidative and endoplasmic reticulum stress (ERS) can elicit inflammatory responses, and persistent oxidative and ERS also may lead to apoptotic cascades, which is associated with the pathogenesis of multiple diseases. β-carotene, a natural carotenoid, has potential anti-inflammatory and antioxidant functions. However, the effect of β-carotene on apoptosis in weaned piglets and the detailed molecular mechanism remain unclear. In this study, we found that β-carotene decreased malondialdehyde (MDA) levels and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in piglet serum. β-carotene could inhibit the mRNA levels of caspase-3 significantly, but had no significant inhibitory effect of the mRNA levels of caspase-9 and caspase-12 in the piglet jejunum. In addition, β-carotene decreased the activation of GRP78, CHOP, and JNK/p38 MAPK and the ratio of Bax/Bcl-2. Furthermore, β-carotene had a significant influence on the activation of ERS and apoptosis-related signals in TG-induced IPEC-J2. In the present study, β-carotene pre-treatment attenuated the ratio of Bax/Bcl-2 and prevented TG-induced increases in the level of PERK-CHOP and IRE1-JNK/p38 MAPK pathway activation in a dose-dependent manner. Overall, these findings indicate that β-carotene may protect weaning-induced apoptosis through inhibiting ERS.

Effects of supplemental β-carotene on colostral immunoglobulin and plasma β-carotene and immunoglobulin in Japanese Black cows

Data from 26 Japanese Black cows were collected to clarify the effects of supplemental β-carotene on colostral immunoglobulin (Ig) and plasma β-carotene and Ig in the cows. Cows were assigned to control or β-carotene groups from 21 days before the expected calving date to 60 days after parturition. Supplemental β-carotene was provided at 500 mg/day in the β-carotene group. Supplemental β-carotene drastically increased plasma β-carotene concentrations in the cows from parturition to 60 days after parturition, and plasma β-carotene concentrations in the control and β-carotene groups at parturition were 202 and 452 μg/dl, respectively. Supplemental β-carotene had no effects on plasma IgG₁ , IgA or IgM concentrations at parturition. Supplemental β-carotene increased colostral IgG₁ concentrations in the cows, but colostral β-carotene, IgA and IgM concentrations were not affected by supplemental β-carotene. These results indicate that supplemental β-carotene is effective to enhance colostral IgG₁ concentrations and plasma β-carotene concentrations in Japanese Black cows.

Non-Provitamin A and Provitamin A Carotenoids as Immunomodulators: Recommended Dietary Allowance, Therapeutic Index, or Personalized Nutrition?

Vegetables and fruits contain non-provitamin A (lycopene, lutein, and zeaxanthin) and provitamin A (β-carotene, β-cryptoxanthin, and α-carotene) carotenoids. Within these compounds, β-carotene has been extensively studied for its health benefits, but its supplementation at doses higher than recommended intakes induces adverse effects. β-Carotene is converted to retinoic acid (RA), a well-known immunomodulatory molecule. Human interventions suggest that β-carotene and lycopene at pharmacological doses affect immune functions after a depletion period of low carotenoid diet. However, these effects appear unrelated to carotenoids and retinol levels in plasma. Local production of RA in the gut-associated lymphoid tissue, as well as the dependency of RA-induced effects on local inflammation, suggests that personalized nutrition/supplementation should be considered in the future. On the other hand, the differential effect of RA and lycopene on transforming growth factor-beta suggests that lycopene supplementation could improve immune functions without increasing risk for cancers. However, such preclinical evidence must be confirmed in human interventions before any recommendations can be made.

Carotenoids: biochemistry, pharmacology and treatment

Carotenoids and retinoids have several similar biological activities such as antioxidant properties, the inhibition of malignant tumour growth and the induction of apoptosis. Supplementation with carotenoids can affect cell growth and modulate gene expression and immune responses. Epidemiological studies have shown a correlation between a high carotenoid intake in the diet with a reduced risk of breast, cervical, ovarian, colorectal cancers, and cardiovascular and eye diseases. Cancer chemoprevention by dietary carotenoids involves several mechanisms, including effects on gap junctional intercellular communication, growth factor signalling, cell cycle progression, differentiation-related proteins, retinoid-like receptors, antioxidant response element, nuclear receptors, AP-1 transcriptional complex, the Wnt/β-catenin pathway and inflammatory cytokines. Moreover, carotenoids can stimulate the proliferation of B- and T-lymphocytes, the activity of macrophages and cytotoxic T-cells, effector T-cell function and the production of cytokines. Recently, the beneficial effects of carotenoid-rich vegetables and fruits in health and in decreasing the risk of certain diseases has been attributed to the major carotenoids, β-carotene, lycopene, lutein, zeaxanthin, crocin (/crocetin) and curcumin, due to their antioxidant effects. It is thought that carotenoids act in a time- and dose-dependent manner. In this review, we briefly describe the biological and immunological activities of the main carotenoids used for the treatment of various diseases and their possible mechanisms of action.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Effects of β-carotene-enriched dry carrots on β-carotene status and colostral immunoglobulin in β-carotene-deficient Japanese Black cows

Data from 18 β-carotene-deficient Japanese Black cows were collected to clarify the effects of feeding β-carotene-enriched dry carrots on β-carotene status and colostral immunoglobulin (Ig) in cows. Cows were assigned to control or carrot groups from 3 weeks before the expected calving date to parturition, and supplemental β-carotene from dry carrots was 138 mg/day in the carrot group. Plasma β-carotene concentrations in the control and carrot groups at parturition were 95 and 120 μg/dL, and feeding dry carrots slightly improved plasma β-carotene at parturition. Feeding dry carrots increased colostral IgA concentrations in cows and tended to increase colostral IgG₁ , but colostral IgM, IgG₂ , β-carotene and vitamin A were not affected by the treatment. Feeding dry carrots had no effects on plasma IgG₁ , IgA and IgM concentrations in cows, but plasma IgG₁ concentrations decreased rapidly from 3 weeks before the expected calving date to parturition. These results indicate that feeding β-carotene-enriched dry carrots is effective to enhance colostral IgA and IgG₁ concentrations in β-carotene-deficient cows.

Nasal fluid secretory immunoglobulin A levels in children with allergic rhinitis

OBJECTIVES

There is growing knowledge about the immunoregulatory and possibly preventative roles of immunoglobulin A (IgA) in allergic diseases. This study aimed to investigate secretory immunoglobulin A (SIgA) levels in the nasal fluid of children who were either being treated for their allergic rhinitis (AR) with intranasal mometasone furoate or were not receiving treatment.

METHODS

The study population contained 55 children with persistent AR. Group I included 27 newly diagnosed AR patients not taking any medication and group II included 28 patients treated with intranasal steroids for at least 6 months. 27 healthy control subjects were also enrolled in the study. Total symptom scores (TSS) were calculated for each patient. Nasal secretions were obtained using a new modified polyurethane sponge absorption method, and samples were analysed by ELISA.

RESULTS

The median value for nasal fluid SIgA level in each group was 127.2μg/ml (interquartile range; 67.3-149.6) in group I, 133.9μg/ml (102.1-177.8) in group II and 299.8μg/ml (144.5-414.0) in the control group. Groups I and II both had statistically significant reductions in nasal fluid SIgA levels compared to the control group (p<0.001). However, there was no statistically significant difference between groups I and II (p=0.35). A statistically significant and negative correlation also existed between TSS and nasal fluid SIgA levels in both groups I and II (p=0.006, rho=-0.512 and p=0.01, rho=-0.481, respectively).

CONCLUSIONS

SIgA levels in the nasal fluid are significantly reduced in children with AR independent of treatment and are negatively correlated with the TSS.

Relationships between immunoglobulin and fat-soluble vitamins in colostrum of Japanese Black multiparous cows

Data from 19 Japanese Black multiparous cows were collected to clarify the relationships among immunoglobulin (Ig) G, IgA, β-carotene, vitamin A and α-tocopherol contents in colostrum of cows in order to evaluate the role of fat-soluble vitamins on colostral IgG and IgA production. Mean colostral IgG was 141 mg/mL, ranging from 65 to 208 mg/mL, whereas mean colostral IgA was 8.7 mg/mL, ranging from 1.0 to 34.6 mg/mL. Colostral IgG increased with aging in multiparous cows. There were positive correlations between colostral IgG and colostral vitamin A or colostral α-tocopherol in cows, and the higher adjusted R(2) was obtained in the prediction model of colostral IgG from age and colostral vitamin A. Colostral vitamin A was positively correlated with colostral β-carotene or colostral α-tocopherol in cows, but there were no relationships between colostral IgA and colostral IgG or colostral fat-soluble vitamins. These results indicate that fat-soluble vitamin contents in colostrum of cows may change in similar patterns and high colostral vitamin A is related with high colostral IgG.