Excessive Intake of High-Fructose Corn Syrup Drinks Induces Impaired Glucose Tolerance.

The number of patients with diabetes was approximately 463 million worldwide in 2019, with almost 57.6% of this population concentrated in Asia. Asians often develop type 2 diabetes (T2D), even if they are underweight and consume a smaller amount of food. Soft drinks contain large amounts of sweeteners, such as high-fructose corn syrup (HFCS). Excessive intake of HFCS drinks is considered to be one of the causes of T2D. In the present study, we investigated the effect of excessive consumption of HFCS-water on glucose tolerance and obesity under conditions of controlled caloric intake using a mouse model. Three-week-old male ICR mice were divided into two groups and given free access to 10% HFCS-water or deionized water. The caloric intake was adjusted to be the same in both groups using a standard rodent diet. The excess HFCS-water intake did not lead to obesity, but led to impaired glucose tolerance (IGT) due to insulin-secretion defect. It affected glucose and fructose metabolism; for example, it decreased the expression of glucokinases, ketohexokinase, and glucose transporter 2 in the pancreas. These results suggest that excessive consumption of HFCS drinks, such as soft drinks, without a proper diet, induces nonobese IGT due to insulin-secretion defect.

Enhanced water dispersibility and permeability through a Caco-2 cell monolayer of ß-cryptoxanthin extracted from kumquats by complexation with casein.

ß-Cryptoxanthin (BCX) possesses potential therapeutic and health benefits. However, BCX absorption is low because of its poor aqueous solubility. In this study, a complex between BCX and casein (Cas) was prepared to improve the water dispersibility and bioavailability of BCX. BCX was recovered quantitatively from freeze-dried kumquat powder through solid-liquid extraction and saponification. The complexation significantly improved the apparent solubility of BCX under acidic and neutral conditions. A cell membrane permeation test using a Caco-2 cell monolayer was performed to evaluate the bioavailability of the BCX-Cas complex. This complex and a blank sample were digested in vitro and added to the apical side of the Caco-2 cell membrane. The quantity of BCX that permeated using the BCX-Cas complex after 24 h was 22.7 times greater than that of the blank. Thus, complexation of BCX with Cas improved dramatically the bioavailability of BCX from a kumquat extract.

Analyses of putative anti-cancer potential of three STAT3 signaling inhibitory compounds derived from Salvia officinalis.

The extract of Salvia officinalis (Common Sage) exhibited inhibitory activity of STAT3 signal after screening of several plants extracts using the STAT3-responsive reporter system. Cirsiliol, luteolin, and carnosol were identified from the methanol extract of Silvia officinalis as inhibitors of STAT3 signaling and the effects of these three compounds on STAT3 protein or growth inhibition on cancer cells was compared. Luteolin at the dose of 90 µM clearly suppressed the phosphorylation of STAT3 induced by IL-6, while carnosol was prone to decrease total STAT3 proteins at high doses (>90 µM). Cirsiliol had almost no effect. Since the three compounds exhibited similar concentration-dependent suppression patterns in the reporter assay except for cirsiliol became plateau beyond 30 µM, these compounds appeared to function as STAT3 inhibitory factors in different ways. The direct anti-proliferative activity of three compounds was examined with or without the anti-cancer drug gefitinib using HepG2 and A549 cells. The anti-proliferative effect of the three compounds was additively enhanced by gefitinib. At the doses of 3.6 µM, statistically significant suppression of proliferation was observed in HepG2 cells only by cirsiliol among the three compounds in the absence of gefitinib but all three compounds were prone to suppress the proliferation of HepG2 cells and A549 cells dose-dependently although cirsiliol showed a modest dose-dependency and this suppression of proliferation was enhanced by the addition of gefitinib. Cirsiliol, a dimethyoxylated flavone, activated the natural killer activity of KHYG-1 cells against erythroleukemia K562 cells like a hexamethoxylated flavone, nobiletin, suggesting that it may also have an indirect anti-cancer potential through activation of NK cells. These results shed light on the putative anti-cancer potential of Salvia officinalis.

Immunostimulatory effect of kumquat (Fortunella crassifolia) and its constituents, ß-cryptoxanthin and R-limonene.

Natural killer (NK) cells play an important role in the innate immune system by eliminating cancer cells and virally infected cells. Aging and stress attenuate the activity of NK cells, thereby increasing the risk of various diseases. In this study, we demonstrated that the consumption of a small number of kumquats in an in vivo model could suppress elevated plasma corticosterone levels and reverse the decline in splenocyte cytotoxicity caused by restraint stress. Our results identified ß-cryptoxanthin (BCX) as an active kumquat component with a NK cell-activating effect, and R-limonene as an active component that mediates not only the anti-stress effect but also NK cell activation by oral administration. In addition, BCX, R-limonene, and R-limonene metabolites were found to enhance IFN-γ production in KHYG-1 cells, a human NK cell line. Collectively, our findings suggest that the ingestion of a few kumquats on a daily basis can help to combat stress and enhance NK cell activity.

Naturally occurring 3RS, 7R, 11R-phytanic acid suppresses in vitro T-cell production of interferon-gamma.

BACKGROUND: Among the eight stereoisomers of phytanic acid (PA), the 3RS, 7R, 11R-isomer is naturally occurring and is present in foods and the human body. PA is considered to have possible health benefits in the immune system. However, it remains undetermined whether these effects are elicited by the 3RS, 7R, 11R-PA isomer, because previous studies used a commercially available PA whose isomer configuration is unknown. In this study, we synthesized a preparation of 3RS, 7R, 11R-PA, and investigated its in vitro immunomodulatory effects, especially the T-cell production of interferon (IFN)-γ, which is associated with various autoimmune diseases. This study also investigated the effects of 3RS, 7R, 11R-PA on NF-κB activity in order to address the mechanism of its immunomodulatory effects. METHODS: Mouse splenocytes and purified T-cells were stimulated with T-cell mitogens and incubated with 3RS, 7R, 11R-PA, followed by evaluation of IFN-γ production. The effect of 3RS, 7R, 11R-PA on NF-κB activity was also investigated using an A549 cell line with stable expression of an NF-κB-dependent luciferase reporter gene. RESULTS: 3RS, 7R, 11R-PA significantly reduced in vitro IFN-γ production at both the protein and mRNA levels, and was accompanied by decreased expression of T-bet, a key regulator of Th1 cell differentiation. The results indicated that NF-κB-mediated transcriptional activity was significantly decreased by 3RS, 7R, 11R-PA and that GW6471, an antagonist of peroxisome proliferator activated receptor α (PPARα), abrogated the inhibitory effect of 3RS, 7R, 11R-PA on NF-κB activity. CONCLUSIONS: The present study suggests that 3RS, 7R, 11R-PA is a functional and bioactive fatty acid, and has a potentially beneficial effect for amelioration of T-cell mediated autoimmune diseases. This study also indicates that interference in the NF-κB pathway via PPARα activation is a potential mechanism of the immunomodulatory effects of 3RS, 7R, 11R-PA.

A novel in vitro model of sarcopenia using BubR1 hypomorphic C2C12 myoblasts.

Sarcopenia is the age-related loss of skeletal muscle mass and function with adverse outcomes that include physical disability, poor quality of life, and death. The detailed molecular mechanisms remain unknown. An in vitro muscle atrophy model is needed to enable mechanistic studies. To create such a model, we employed BubR1 insufficiency which causes premature ageing in mice. Using C2C12 cells, a recognized in vitro model of the skeletal muscle cell, we obtained the BubR1 hypomorphic C2C12 (C2C12BKD) cells by using shRNA. The resulting C2C12BKD cells displayed several characteristics of the sarcopenic muscle cell. In C2C12BKD cells, formation of myotubes, assessed by analysis of fusion index, was markedly reduced as was the expression of myogenin and MyoD, two marker genes for myogenesis. Moreover, the cells showed increased expression of the muscle-specific ubiquitin ligases Atrogin-1 and MuRF-1, indicating increased protein degradation through the ubiquitin-proteasome dependent proteolytic pathway. These results suggest that C2C12BKD cells are potentially useful as a novel in vitro model of sarcopenia.

Effect of kumquat (Fortunella crassifolia) pericarp on natural killer cell activity in vitro and in vivo.

Natural killer (NK) cells play a key role in innate immune defense against infectious disease and cancer. A reduction of NK activity is likely to be associated with increased risk of these types of disease. In this study, we investigate the activation potential of kumquat pericarp acetone fraction (KP-AF) on NK cells. It is shown to significantly increase IFN-γ production and NK cytotoxic activity in human KHYG-1 NK cells. Moreover, oral administration of KP-AF significantly improves both suppressed plasma IFN-γ levels and NK cytotoxic activity per splenocyte in restraint-stressed mice. These results indicate that raw kumquat pericarp activates NK cells in vitro and in vivo. To identify the active constituents, we also examined IFN-γ production on KHYG-1 cells by the predicted active components. Only ß-cryptoxanthin increased IFN-γ production, suggesting that NK cell activation effects of KP-AF may be caused by carotenoids such as ß-cryptoxanthin.

Efficient approach for simultaneous estimation of multiple health-promoting effects of foods.

The investigation of new food constituents for purposes of disease prevention or health promotion is an area of increasing interest in food science. This paper proposes a new system that allows for simultaneous estimation of the multiple health-promoting effects of food constituents using informatics. The model utilizes expression data of intracellular marker proteins as descriptors that reply to stimulation of a constituent. To estimate three health-promoting effects, namely, cancer cell growth suppression activity, antiviral activity, and antioxidant stress activity, each model was constructed using expression data of marker proteins as input data and health-promoting effects as the output value. When prediction performances of three types of mathematical models constructed by simple, multiple regressions, or artificial neural network (ANN), were compared, the most adequate model was the one constructed using an ANN. There were no statistically significant differences between the actual data and estimated values calculated by the ANN models. This system was able to simultaneously estimate health-promoting effects with reasonable precision from the same expression data of marker proteins. This novel system should prove to be an interesting platform for evaluation of the health-promoting effects of food.

Immuno-chromatographic assay for diagnosis of feline leukemia virus infection.

Feline leukemia virus (FeLV) infectious disease is one of feline infection diseases spreading broadly all over the world. For bedside diagnosis of FeLV infectious disease, an immuno-chromatographic assay was investigated. Five different monoclonal antibodies were developed against the major core protein FeLV-p27. Among them, the combination of FL6 and FL12, which had little epitopic overlap each other, showed the highest sensitivity with no cross-reaction to the other feline virus antigens when they were employed to the immuno-chromatographic assay. The system had a practical detection limit of 0.5 ng of FeLV-p27 per 0.1 ml of feline sera within 15 min. In comparison with clinical standard methods, the system gave rapidly and accurately the same diagnosis with neither false negative nor false positive. Moreover, it did not need any pretreatment of blood specimen.

Decreased susceptibility of leukemic cells with PIG-A mutation to natural killer cells in vitro.

The cloning of the PIG-A gene has facilitated the unraveling of the complex pathophysiology of paroxysmal nocturnal hemoglobinuria (PNH). Of current major concern is the mechanism by which a PNH clone expands. Many reports have suggested that an immune mechanism operates to cause bone marrow failure in some patients with PNH, aplastic anemia, and myelodysplastic syndromes. Because blood cells of PNH phenotype are often found in patients with these marrow diseases, one hypothesis is that the PNH clone escapes immune attack, producing a survival advantage by immunoselection. To test this hypothesis, we examined the sensitivity of blood cells, with or without PIG-A mutations, to killing by natural killer (NK) cells, using 51Cr-release assay in vitro. To both peripheral blood and cultured NK cells, PIG-A mutant cells prepared from myeloid and lymphoid leukemic cell lines were less susceptible than their control counterparts (reverted from the mutant cells by transfection with a PIG-A cDNA). NK activity was completely abolished with concanamycin A and by calcium chelation, indicating that killing was perforin-dependent. There were no differences in major histocompatibility (MHC) class I expression or sensitivity to either purified perforin or to interleukin-2-activated NK cells between PIG-A mutant and control cells. From these results, we infer that PIG-A mutant cells lack molecules needed for NK activation or to trigger perforin-mediated killing. Our experiments suggest that PIG-A mutations confer a relative survival advantage to a PNH clone, contributing to selective expansion of these cells in the setting of marrow injury by cytotoxic lymphocytes.