Effects of High-Protein Diet and/or Resveratrol Supplementation on the Immune Response of Irradiated Rats

Preparation of resveratrol dry suspension and its immunomodulatory and anti-inflammatory activity in mice

Context: Resveratrol is a natural polyphenol compound. It exhibits antitumor, immunostimulatory, and antiviral activities. However, poor water solubility and structural instability limit its administration and storage.Objective: A resveratrol dry suspension (RDS) was prepared and immunomodulatory effect in immunosuppressive mice induced by cyclophosphamide and anti-inflammatory activities in mice were evaluated.Materials and methods: The preparation of RDS was optimized by the orthogonal design method. To evaluate the immunomodulatory effects, SPF Kunming mice were divided into seven groups comprising of nine males and nine females for each group. The RDS supplemented group was administrated doses of 3.33, 1.67, and 0.83 g/kg/d. Then visceral index, lymphocyte proliferation, the ratio of CD3⁺ CD4⁺/CD3⁺ CD8⁺, and the contents of cytokines in serum were tested. To ameliorate effects of acetic acid induced capillary permeability, xylene-based ear oedema, and cotton pellet granuloma, RDS as anti-inflammatory agent was administered at doses of 1, 0.33, and 0.1 g/kg/d as compared to indomethacin (IM) provided as a positive control at 10 mg/kg.Results: RDS inhibited the degradation of resveratrol and enhanced the CD3⁺ CD4⁺/CD3⁺ CD8⁺ ratio, spleen index, IL-2 level, and splenic lymphocytes in immunosuppressive mice. RDS (0.1 g/kg/d) significantly inhibited the acetic acid-induced capillary permeability, and at doses of 0.33 and 1 g/kg/d repressed the ear swelling and granuloma formation in immunocompromised mice.Discussion and Conclusion: RDS is a stable, cheaper, and suitable preparation with potent immunoregulatory and anti-inflammatory activities. Keeping in view these remarkable properties, RDS could be an appropriate preparation for clinic use of resveratrol.

Protection Against Ionizing Radiation-Induced Normal Tissue Damage by Resveratrol: A Systematic Review

The use of some agents as radioprotectors has been evaluated for protection against normal tissue toxicity following exposure to ionizing radiation. Resveratrol, a natural flavonoid, with antioxidant and anti-inflammatory properties has attracted research interests for its radioprotective potential. This study systematically evaluates existing studies to examine the radioprotective effectiveness of resveratrol. A literature search of the electronic databases, including PubMed, Scopus, and Embase was conducted to retrieve articles investigating the protective effect of resveratrol against ionizing radiation-induced damage to normal tissues. The search timeframe ranged from the inception of each database to January 2020. From an initial search of 231 articles, and after the removal of duplicates as well as applying the predetermined inclusion and exclusion criteria, 33 articles were finally included for this systematic review. Results showed promising protective effect of resveratrol against ionizing radiation-induced damage to normal tissues. Furthermore, no adverse effect was observed after administering resveratrol. Resveratrol showed the potential to protect against ionizing radiation-induced damage to normal tissue cells via notable mechanisms, including anti-apoptotic and anti-inflammatory effects. However, further studies on the efficacy of clinical translation of resveratrol would open up more insights, while other gray areas such as the optimal radioprotective dosage of resveratrol requires further investigation. Overall, resveratrol is a potential double-edged sword in cancer therapy while protecting healthy tissues.

A Novel Resveratrol-Arsenic Trioxide Combination Treatment Synergistically Induces Apoptosis of Adriamycin-Selected Drug-Resistant Leukemia K562 Cells

Leukemia cells can develop resistance to apoptosis induced by chemotherapeutic agents. Concomitant multidrug resistance of cells remains the greatest clinical obstacle in the effective treatment of blood and solid tumors. Natural products have been identified that possess the capacity to modulate chemotherapeutic resistance and induce apopotosis. In this study, we generated adriamycin-resistant K562 leukemia (K562/RA) cells and compared the responses of sensitive and resistant leukemia cells to the natural products arsenic trioxide (ATO) and resveratrol (Rsv), with a view to determining whether Rsv potentiates the sensitivity of drug-resistant cells to ATO-induced apoptosis and the associated molecular mechanisms. Our results showed that resistance of K562/RA cells induced by adriamycin treatment was significantly higher (115.81-fold) than that of parental K562 cells. Simultaneously, K562/RA cells were cross-resistant to multiple agents, with the exception of ATO. Rsv enhanced the sensitivity of K562/RA cells to ATO and reduced the required dose of ATO as well as associated adverse reactions by promoting the proliferation inhibitory and apoptosis-inducing effects of ATO, which may be associated with reduced expression of the drug resistance genes mdr1/P-gp, mrp1/MRP1 and bcrp/BCRP, as well as the apoptotic inhibitory genes bcl-2, NF-κB and P53, and conversely, activation of caspase-3. Our collective findings indicate that ATO and Rsv synergistically enhance the sensitivity of drug-resistant leukemia cells to apoptosis.

Effects of plant and animal high protein diets on immune-inflammatory biomarkers: A 6-week intervention trial

BACKGROUND & AIMS

Pro-inflammatory biomarkers are well-established contributors to insulin resistance and represent valid targets for diabetes management and prevention. Yet, little is known whether nutrition could play a role in modulating various aspects of immune-inflammatory responses. Our aim is to assess the effect of isocaloric animal and plant protein dietary interventions on selected biomarkers representing various immune-inflammatory pathways.

METHODS

We enrolled 37 participants with type 2 diabetes (age 64 ± 6 years, body mass index 30.2 ± 3.6 kg/m², glycated hemoglobin 7.0 ± 0.6%) who underwent an either high-animal protein (AP) or high-plant protein (PP) diet (30 E% protein, 40 E% carbohydrates, 30 E% fat) for 6-weeks. Clinical examinations were performed at beginning and end of the study. Levels of pro-inflammatory adipokines [chemerin, progranulin], cytokines [tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), soluble urokinase-type plasminogen activator receptor (suPAR), transforming growth factor beta 1 (TGF-β1)], and proteins [calprotectin, lactoferrin and growth differentiation factor 15 (GDF-15)] were determined in blood serum using enzyme-linked immunosorbent assay.

RESULTS

Chemerin and progranulin concentrations decreased following AP and PP diets. TGF-β1 increased in AP and decreased in PP, whereas calprotectin increased in PP and decreased in AP. No statistically significant differences in the concentrations of IL-6, TNF-α, suPAR, lactoferrin and GDF-15 could be seen in either of the protein diet arms.

CONCLUSIONS

These results suggest that both AP and PP diets may effectively reduce the levels of the pro-inflammatory adipokines chemerin and progranulin. The effects on the additional immune-inflammatory biomarkers seem to be more complex.

CLINICAL TRIAL REGISTRY NUMBER

NCT02402985 (ww.clinicaltrials.gov).

Subchronic toxicity evaluation of leaves from rabbiteye blueberry (Vaccinium virgatum Aiton) in rats

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Blueberry leaf may contain multiple compounds with beneficial effects, but limited about the safety.

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Powdered blueberry leaf has no toxic event at oral dose of daily 500, 1000 and 2500 mg/kg for 90 days in SD rats.

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No significant changes in food consumption, body weight gain and organ weights.

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A daily dose up to 2,500 mg/kg body weight in both the sexes rats may indicate a NOAEL.

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An acceptable daily intake of blueberry leaf powder for humans is calculated to be 25 mg in dry weight per kg body weight.

Blueberry leaf may contain multiple compounds with beneficial effects. We conducted a 90-day toxicity study in rats to evaluate the safety of consuming the leaves of rabbiteye blueberry (Vaccinium virgatum Aiton; RB species). Powdered leaves were administered daily by oral gavage at doses of 500, 1000, and 2500 mg/kg body weight to male and female Sprague-Dawley rats for 90 days. Treatment did not result in death or changes in the behavior and external appearance of the animals. No alterations were observed in hematological and serum chemical parameters, urinalysis, food consumption, body weight gain, or absolute and relative organ weights at the end of the treatment period, with the exception of some leukocyte percentages in male rats treated with 500 and 1000 mg/kg blueberry leaf powder. The findings indicate that rabbiteye blueberry leaf is safe for consumption and should be investigated as a candidate functional food.

Effect of Resveratrol Dry Suspension on Immune Function of Piglets

Resveratrol, a polyphenolic plant antitoxin, has a wide range of pharmacological activities. In this study, we systematically evaluated the effects of resveratrol dry suspension (RDS) on immune function in piglets that were treated with different doses of RDS for 2 weeks. The results showed that the RDS has significant effects on the development, maturation, proliferation, and transformation of T lymphocytes. RDS could regulate humoral immune responses by upregulating the release of IFN-γ and downregulating the release of TNF-α. After piglets were vaccinated against classical swine fever virus and foot-and-mouth disease virus, the antibody titers were significantly increased. RDS treatment showed an excellent resistance to enhance T-SOD activity. Values of blood routine and blood biochemistry showed no toxicity. These results suggested that RDS could be considered as an adjuvant to enhance immune responses to vaccines, as well as dietary additives for animals to enhance humoral and cellular immunity.

Resveratrol promotes recovery of immune function of immunosuppressive mice by activating JNK/NF-κB pathway in splenic lymphocytes

Resveratrol, a natural compound found in over 70 plants, is known to possess immunoregulatory effects and anti-inflammatory activity. It has been shown that resveratrol has regulatory effects on different signaling pathways in different diseases. However, few reports have evaluated the effects of resveratrol on reinforcing immunity recovery via activating nuclear factor-κB (NF-κB) pathway and Jun N-terminal kinases (JNK) pathway. The present study aimed to assess immune-enhancing activity and underlying mechanism of resveratrol in immunosuppressive mice. Previously, we reported that resveratrol could promote mouse spleen lymphocyte functions to recover the immune system effectively. In the present study, we show that resveratrol could upregulate the expressions of NF-κB, IκB kinase, JNK, and c-jun in splenic lymphocytes of immunosuppressive mice. Taken together, our results indicate that resveratrol could promote recovery of immunologic function in immunosuppressive mice by activating JNK/NF-κB pathway.

Distinct metabolic effects of resveratrol on lipogenesis markers in mice adipose tissue treated with high-polyunsaturated fat and high-protein diets

OBJECTIVE

A healthy diet is essential for the prevention of metabolic syndrome. The present study evaluated the effect of resveratrol associated with high-polyunsaturated fat and high-protein diets on expression of adipogenic and lipogenic genes.

RESEARCH METHODS & PROCEDURES

FVB/N mice were divided into 6 groups (n=7 each) and fed with experimental diets for 60days: standard (ST), high-fat diet (HFD), and high-protein diet (HPD), with and without resveratrol (RSV) (4g/kg diet). The body weight, food intake, energy intake (kcal), and blood parameters (HDL-C, total cholesterol, glucose, and triglyceride levels) were assessed. Real-time PCR was performed to analyze the expression of adipogenesis and lipogenesis markers: PPARγ, SREBP-1c, ACC and FAS in samples from perigonadal adipose tissue.

RESULTS

In the HPD+RSV group, resveratrol decreased body weight, body adiposity, adipose tissue weight, adipocyte area, total cholesterol, ACC and FAS expression, and increased HDL-cholesterol in comparison to HPD. In the HPD group there was a decrease in adipocyte area, as well as PPARγ, SREBP-1c and ACC expression in comparison to ST. While in HFD+RSV, resveratrol decreased levels of total cholesterol in comparison to HFD. In the HFD group there was decrease in body weight, and PPARγ, SREBP-1c and ACC expression in comparison to ST.

CONCLUSIONS

The obtained results show that resveratrol decreases lipogenesis markers and metabolic parameters in the setting of a high-protein diet. Moreover, resveratrol decreased total cholesterol in both diets. These results point to the increased potential of resveratrol use in prevention of metabolic syndrome, acting on different dietary compositions.