Short-Chain Fatty Acids Promote Immunotherapy by Modulating Immune Regulatory Property in B Cells.

The dysfunction of regulatory B cells (Breg) may result in immune inflammation such as allergic rhinitis (AR); the underlying mechanism is not fully understood yet. Short-chain fatty acids, such as propionic acid (PA), have immune regulatory functions. This study is aimed at testing a hypothesis that modulates PA production alleviating airway allergy through maintaining Breg functions. B cells were isolated from the blood obtained from AR patients and healthy control (HC) subjects. The stabilization of IL-10 mRNA in B cells was tested with RT-qPCR. An AR mouse model was developed to test the role of PA in stabilizing the IL-10 expression in B cells. We found that the serum PA levels were negatively correlated with the serum Th2 cytokine levels in AR patients. Serum PA levels were positively associated with peripheral CD5+ B cell frequency in AR patients; the CD5+ B cells were also IL-10+. The spontaneous IL-10 mRNA decay was observed in B cells, which was prevented by the presence of PA through activating GPR43. PA counteracted the effects of Tristetraprolin (TTP) on inducing IL-10 mRNA decay in B cells through the AKT/T-bet/granzyme B pathway. Administration of Yupinfeng San, a Chinese traditional medical formula, or indole-3-PA, induced PA production by intestinal bacteria to stabilize the IL-10 expression in B cells, which promoted the allergen specific immunotherapy, and efficiently alleviated experimental AR. In summary, the data show that CD5+ B cells produce IL-10. The serum lower PA levels are associated with the lower frequency of CD5+ B cells in AR patients. Administration with Yupinfeng San or indole-3-PA can improve Breg functions and alleviate experimental AR.

Identification of antigen-specific neutrophils in the tonsils with recurrent acute inflammation.

The pathogenesis of recurrent acute tonsillitis (Rtn) is to be further investigated. Polymorphonuclear neutrophils (PMN) often associate with the pathogenesis of acute and chronic inflammation. This study aims to identify the antigen-specific PMNs (sPMNs) isolated from the tonsillar tissues with recurrent acute inflammation. In this study, CD66b+ PMNs were isolated from surgically removed tonsils (40 tonsils were from 20 Rtn patients; 24 tonsils were from 12 tonsil tumour patients) by flow cytometry cell sorting. sPMNs were identified through immunological approaches. We found that compared with the control tonsil samples (from marginal non-tumour tissues of tonsil cancer), Rtn samples showed higher PMN frequency, higher levels of myeloperoxidase (MPO) and neutrophil elastase (NE), in which positive correlation was detected between the inflammatory scores in the Rtn tissues and PMN counts (r = .7352; p = .0002), or MPO (r = .6565, p = .0017), or NE (r = .6687, p = .0013). Upon exposure to tonsillar tissue protein extracts in the culture, a portion of Rtn PMNs was activated and released inflammatory mediators. A complex of tonsillar tissue-specific IgG and FcγRI was observed on the surface of Rtn PMNs; these PMNs could specifically recognize the Rtn tissue extracts and were designated the tonsillar antigen-specific PMNs (sPMNs). A signal transduction pathway of mitogen-activated protein kinase (MAPK)-nuclear factor of T cell activation (NFAT) was activated in sPMNs after exposure to Rtn tissue extracts. In summary, a fraction of sPMN in the Rtn tonsillar tissues was identified and characterized. The sPMNs can be activated upon exposure to tonsil-specific antigens. These sPMNs may contribute to the Rtn pathogenesis.

Evaluation of toxicity studies of flavonoid fraction of Lithocarpus polystachyus Rehd in rodents.

The aim of the study was to evaluate the safety of flavonoid fraction of Lithocarpus polystachyus Rehd (Sweet Tea-F, ST-F) in mice and rats through acute and sub-chronic toxicity studies respectively. For acute toxicity study, a single dose of 5000 mg/kg of ST-F was given orally to healthy KM mice. The mice were observed mortality and toxic symptoms for 24 h, then once a day up to 14 days. In the sub-chronic toxicity study, ST-F was administered orally at doses of 0, 70, 140, 560 mg/kg/day to rats for 26 weeks. Body weight and food intake were recorded weekly. Hematological, biochemical, coagulation and organ parameters were analyzed at the end of 26 weeks administration. Vital organs were evaluated by histopathology. In the acute toxicity study, ST-F caused neither significant toxic symptoms, nor mortality in mice. In sub-chronic toxicity study, daily oral administration of ST-F at the dose of 70 mg/kg resulted in a significant increase (P < 0.05) in the relative body weight at the 10-week, and the same situation brought at the dose of 140 mg/kg/day at the 22-week. Hematological and biochemical showed significant changes (P < 0.01 or P < 0.05) in WBC, GLU, ALP, AST and serum electrolytes levels at the dose of 560 mg/kg/day. The amount of RBC decreased significantly (P < 0.05) while the content of PLT slightly increased (P < 0.05) at the dose of 140 mg/kg/day. In additional, no obvious histological changes were observed in vital organs of ST-F treated animals compared to control group. The ST-F may be exit slight side effects at the dose of 560 mg/kg/day in rats. Thus, the overall results show that the no-observed adverse effect level (NOAEL) of ST-F was considered to be 140 mg/kg for male SD rats.

Salvianolic Acid B Ameliorates Hyperglycemia and Dyslipidemia in db/db Mice through the AMPK Pathway.

BACKGROUND/AIMS: Salvianolic acid B (Sal B), a major polyphenolic compound of Salvia miltiorrhiza Bunge, has been shown to possess potential antidiabetic activities. However, the action mechanism of SalB in type 2 diabetes has not been investigated extensively. The present study was designed to investigate the effects of Sal B on diabetes-related metabolic changes in a spontaneous model of type 2 diabetes, as well as its potential molecular mechanism. METHODS: Male C57BL/KsJ-db/db mice were orally treated with Sal B (50 and 100 mg/kg) or metformin (positive drug, 300 mg/kg) for 6 weeks. RESULTS: Both doses of Sal B significantly decreased fasting blood glucose, serum insulin, triglyceride and free fatty acid levels, reduced hepatic gluconeogenic gene expression and improved insulin intolerance in db/db mice. High dose Sal B also significantly improved glucose intolerance, increased hepatic glycolytic gene expression and muscle glycogen content, and ameliorated histopathological alterations of pancreas, similar to metformin. Sal B treatment resulted in increased phosphorylated AMP-activated protein kinase (p-AMPK) protein expression in skeletal muscle and liver, increased glucose transporter 4 (GLUT4) and glycogen synthase protein expressions in skeletal muscle, and increased peroxisome proliferator-activated receptor alpha (PPARα) and phosphorylated acetyl CoA carboxylase (p-ACC) protein expressions in liver. CONCLUSION: Our data suggest that Sal B displays beneficial effects in the prevention and treatment of type 2 diabetes at least in part via modulation of the AMPK pathway.

Sweet tea leaves extract improves leptin resistance in diet-induced obese rats.

AIM OF THE STUDY: Dietary obesity is usually characterized by leptin resistance and abnormal lipid metabolism. Lithocarpus polystachyus Rehd.(Sweet Tea) leaf is a kind of Chinese folkloric medicine, and it has been widely used for obesity, diabetes, and hypertension in South China. The present study is aimed at investigating the pharmacological mechanism of the anti-hyperleptinaemia effects of Sweet Tea leaves extract in high fat diet-induced obese rats. MATERIALS AND METHODS: We induced high fat diet obesity for 14 weeks to test the corrective effects of three ST doses (75, 150 and 300 mg/kg per day) for 8 weeks. At the end of the experiment, body weight, fasting blood glucose and serum lipids, superoxide dismutase (SOD), malondialdehyde (MDA), fasting serum insulin and leptin, C-reactive protein, adiponectin and resistin levels were measured, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was also calculated. mRNA gene expression of PPARγ (peroxisome proliferator-activated receptor γ) and C/EBPα(CCAAT/enhancer-binding protein α) in epididymal adipose tissue of DIO control and experimental groups were evaluated. RESULTS: Sweet Tea leaves extract could significantly decrease the levels of serum lipids, attenuate body weight gain and lower circulating leptin and insulin levels, ameliorate the state of oxidative stress, raise serum adiponectin, reduce circulating CRP and resistin levels, and depress the expression of PPARγ and C/EBPα in epididymal adipose tissue of obese rats. CONCLUSION: The present findings suggest that ST can effectively attenuate the leptin resistance at least through anti-hyperlipidemic activity and thus has the therapeutic potential in treating hyperlipidemia and hyperleptinaemia related to dietary obesity.

[Effect of Nuanxin Capsule on two rat models with heart failure].

OBJECTIVE: To observe the effects of Nuanxin Capsule (NC) on the rat models of heart failure induced by abdominal aorta constriction and adriamycin. METHODS: Rats were randomly divided into the following groups: model control group, low-dose and high-dose, and digoxin group. Meanwhile, the pseudo-operation and NC groups were seperately established. After treatment for 30 days, the heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximal rate of increase and decrease in left ventricular pressure (+/- dp/dt), mean peripheral blood pressure (MBP) as well as levels of serum superoxide dismustase (SOD), malondialdeh-vde (MDA), cardiac index and heart size were measured. RESULTS: SBP, LVSP, +/- dp/dt and SOD activity increased,while LVEDP,serum MDA levels decreased in high and low-dose NC groups of two models. The heart rates also decreased, but the difference was insignificant (P>0.05, compared with those of model group). Besides, the heart rate,heart size and cardiac index, as well as serum Ang II levels also decreased. The differences were significant as compared with the digoxin group (P>0.05). The high-dose NC also significatly improved MBP and SOD (P<0.05 and P<0.01). CONCLUSION: Nuanxin Capsule has good therapeutic effects on the rats models of adriamycin and abdominal aorta constriction induced heart failure.

The hypoglycemic activity of Lithocarpus polystachyus Rehd. leaves in the experimental hyperglycemic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaves of Lithocarpus polystachyus Rehd. are used for the treatment of disorders such as diabetes, hypertension, and epilepsy in folk medicine of South China. The possible antidiabetic effects of the leaves were investigated in experimental type 2 and type 1 diabetic rats. MATERIALS AND METHODS: Type 2 diabetic rats received orally three different extracts of Lithocarpus polystachyus Rehd. leaves for 4 weeks (aqueous extract [ST-1], ethanol extract [ST-2], flavonoid-rich fraction [ST-3]). At the end of the experiment biochemical parameters were tested and livers and pancreases were excised for histological study. After the comparison of the pharmacological test results of the three extracts, the one which showed the best bioactivity was further studied to confirm its antidiabetes effect on both type 2 and type 1 diabetic rats. RESULTS: Compared to ST-1 and ST-2, ST-3 had better effects on regulation of blood glucose, glycosylated serum protein, cholesterol, triglyceride, malondialdehyde, superoxide dismutase and attenuation of liver injury in type 2 diabetic rats (p<0.01 or p<0.05). ST-3 administration for four weeks also significantly reduced the fasting serum insulin and C-peptide level and improved the insulin tolerance (p<0.05). In type 1 diabetic rats, ST-3 supplement for three weeks caused significant reduction in fasting blood glucose, total cholesterol, triglyceride, urea nitrogen, creatinine and liver mass, along with significantly inhibiting the decline of insulin level compared to diabetic control (p<0.05 or p<0.01). CONCLUSION: The flavonoid-rich fraction of Lithocarpus polystachyus Rehd. leaves (ST-3) had better beneficial effect than that of the ethanol or aqueous extract in experimental diabetic rats, which means that the bioactivity of the herbal leaves is probably due to the presence of flavonoids. The results also strongly suggest that the antidiabetic effect of ST-3 was possibly through multiple mechanisms of action including blood lipid and antioxidant mediation. The results indicated that the aqueous flavonoid-rich fraction of Lithocarpus polystachyus Rehd. leaves possessed significant protective activity in type 2 and type 1 diabetes.