Wai-Hung Sit

Supplementation of Bitter Melon to Rats Fed a High-Fructose Diet During Gestation and Lactation Ameliorates Fructose-Induced Dyslipidemia and Hepatic Oxidative Stress in Male Offspring

This study examined the impact of maternal high-fructose intake and if metabolic control in the offspring could benefit from supplementing bioactive food components such as bitter melon (BM) to the maternal diet. In Expt. 1, virgin female rats received control (C), high-fructose (F; 60%), or BM-supplemented fructose (FBM; 1%) diet before conception until d 21 of lactation. Weaned male offspring were fed the C diet for 11 wk, forming C/C, F/C, and FBM/C groups. The F/C group had elevated serum insulin, TG, and FFA concentrations and hepatic lipid alterations compared with the C/C and FBM/C groups (P < 0.05). The 2 latter groups did not differ. Expt. 2 had similar dam treatment groups, but offspring were weaned to the C or F diet, forming C/C, C/F, F/F, and FBM/F groups, and the dietary treatment was extended to 20 wk. The hepatic levels of stearyl-CoA desaturase and microsomal TG transfer protein mRNA were lower, but that of PPARγ coactivator 1-α and fibroblast growth factor 21 mRNA and fatty acid binding protein 1 protein were higher in the FBM/F group compared with the C/F and F/F groups (P < 0.05), indicating that maternal BM supplementation may reduce lipogenesis and promote lipid oxidation in offspring. The FBM/F group had significantly higher activities of liver glutathione peroxidase, superoxide dismutase, and catalase than the F/F group. The results indicate that supplementing BM to dams could offset the adverse effects of maternal high-fructose intake on lipid metabolism and antioxidant status in adult offspring.

Protective effect of Phellinus linteus polysaccharide extracts against thioacetamide-induced liver fibrosis in rats: a proteomics analysis

BackgroundThe hepatoprotective potential of Phellinus linteus polysaccharide (PLP) extracts has been described. However, the molecular mechanism of PLP for the inhibition of liver fibrosis is unclear. This study aims to investigate the molecular protein signatures involved in the hepatoprotective mechanisms of PLP via a proteomics approach using a thioacetamide (TAA)-induced liver fibrosis rat model.MethodsMale Sprague–Dawley rats were divided into three groups of six as follows: Normal group; TAA group, in which rats received TAA only; and PLP group, in which rats received PLP and TAA. Liver fibrosis was induced in the rats by repeated intraperitoneal injections of TAA at a dose of 200 mg/kg body weight twice a week for 4 weeks. PLP was given orally at a dose of 50 mg/kg body weight twice a day from the beginning of the TAA treatment until the end of the experiment. The development of liver cirrhosis was verified by histological examination. Liver proteomes were established by two-dimensional gel electrophoresis. Proteins with significantly altered expression levels were identified by matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry and the differentially expressed proteins were validated by immunohistochemical staining and reverse transcription polymerase chain reaction.ResultsHistological staining showed a remarkable reduction in liver fibrosis in the rats with PLP treatment. A total of 13 differentially expressed proteins including actin, tubulin alpha-1C chain, preprohaptoglobin, hemopexin, galectin-5, glutathione S-transferase alpha-4 (GSTA4), branched chain keto acid dehydrogenase hterotetrameric E1 subunit alpha (BCKDHA), glutathione S-transferase mu (GSTmu); glyceraldehyde-3-phosphate dehydrogenase (GAPDH); thiosulfate sulfurtransferase (TFT); betaine-homocysteine S-methyltransferase 1 (BHMT1); quinoid dihydropteridine reductase (QDPR); ribonuclease UK114 were observed between the TAA and PLP groups. These proteins are involved in oxidative stress, heme and iron metabolism, cysteine metabolism, and branched-chain amino acid catabolism.ConclusionThe proteomics data indicate that P. linteus may be protective against TAA-induced liver fibrosis via regulation of oxidative stress pathways, heat shock pathways, and metabolic pathways for amino acids and nucleic acids.

Bacterial colonization affects the intestinal proteome of preterm pigs susceptible to necrotizing enterocolitis.

Background: In newborns, colonizing bacteria and enteral nutrition are important for early gut development and immunity. However, in preterm newborns, bacterial colonization, coupled with enteral feeding, can lead to marked intestinal inflammation and disease such as necrotizing enterocolitis (NEC). We hypothesized that the initial bacterial colonization of the gut affects the intestinal proteome independently of enteral feeding. Objective: To identify the intestinal proteins affected by the first colonizing bacteria by comparing the intestinal proteome in formula-fed preterm pigs reared under germ free (GF) or conventional conditions. Methods: Gel-based proteomics of the small intestine to detect proteins that may play a part in the response of the immature intestine to bacterial colonization after birth. Results: Fourteen proteins involved in stress response and detoxification (e.g. heat-shock proteins, peroxiredoxin 1), tissue metabolism and apoptosis (e.g. annexin 2), and some signal transduction pathways were differentially expressed between GF and conventionally reared pigs. Conclusion: The premature intestine is highly responsive to initial bacterial colonization and the specific bacteria-related proteome changes may contribute to the stress response that makes the immature intestine sensitive to the pro-inflammatory effects of enteral feeding.

Temporal proteomic analysis of intestine developing necrotizing enterocolitis following enteral formula feeding to preterm pigs.

Necrotizing enterocolitis (NEC), a serious gastrointestinal inflammatory disease, frequently occurs in preterm neonates that fail to adapt to enteral nutrition. A temporal gel-based proteomics study was performed on porcine intestine with NEC lesions induced by enteral formula feeding. Functional assignment of the differentially expressed proteins revealed that important cellular functions, such as the heat shock response, protein processing; and purine, nitrogen, energy metabolism, were possible involved in the early progression of NEC.

Antibiotics Increase Gut Metabolism and Antioxidant Proteins and Decrease Acute Phase Response and Necrotizing Enterocolitis in Preterm Neonates

Background The appropriate use of antibiotics for preterm infants, which are highly susceptible to develop necrotizing enterocolitis (NEC), is not clear. While antibiotic therapy is commonly used in neonates with NEC symptoms and sepsis, it remains unknown how antibiotics may affect the intestine and NEC sensitivity. We hypothesized that broad-spectrum antibiotics, given immediately after preterm birth, would reduce NEC sensitivity and support intestinal protective mechanisms. Methodology/Principal Findings Preterm pigs were treated with antibiotics for 5 d (oral and systemic doses of gentamycin, ampicillin and metrodinazole; AB group) and compared with untreated pigs. Only the untreated pigs showed evidence of NEC lesions and reduced digestive function, as indicated by lowered villus height and activity of brush border enzymes. In addition, 53 intestinal and 22 plasma proteins differed in expression between AB and untreated pigs. AB treatment increased the abundance of intestinal proteins related to carbohydrate and protein metabolism, actin filaments, iron homeostasis and antioxidants. Further, heat shock proteins and the complement system were affected suggesting that all these proteins were involved in the colonization-dependent early onset of NEC. In plasma, acute phase proteins (haptoglobin, complement proteins) decreased, while albumin, cleaved C3, ficolin and transferrin increased. Conclusions/Significance Depressed bacterial colonization following AB treatment increases mucosal integrity and reduces bacteria-associated inflammatory responses in preterm neonates. The plasma proteins C3, ficolin, and transferrin are potential biomarkers of the colonization-dependent NEC progression in preterm neonates.

The Nephroprotective Effects of the Herbal Medicine Preparation, WH30+, on the Chemical-Induced Acute and Chronic Renal Failure in Rats

In this study, we evaluated the renal protective effects of a Chinese herbal preparation WH30+ in male Wistar rats with glycerol-induced acute renal failure and adenine-induced chronic renal failure. WH30+ is a Chinese herb preparation composed of Rheum Palmatum, Salvia Miltiorrhiza, Cordyceps Sinensis, Leonurus Sibiricus, Epihedium Macranthum, Radix Astragali, and Radix Codonopsis Pilosulae, which has been used to treat kidney deficiency in human. An acute renal failure and chronic renal failure rat model were introduced by glycerol injection (i.m.) and fed with adenine-excessive diet, respectively. WH30+ was administered to rats at the dose of 50 mg/kg/day from 10 days before the diseases were induced until the rats were sacrificed. A reduction in body weight (p < 0.01) was observed in rats with chronic renal failure, but there was no difference between treatment groups. However, the body weight of rats with acute renal failure without treatment was significantly lower than those treated with WH30+ (p < 0.05). Overall, serum creatinine and urea nitrogen were elevated significantly (p < 0.01) in renal failure rats compared to control. Treatment with WH30+ improved both serum creatinine and urea nitrogen slightly in both models. The WH30+-treated rats with acute renal failure had significantly (p < 0.05) greater creatinine clearance than those without treatment. The results of the study show that WH30+ is more effective in the prevention of acute renal failure than chronic renal failure.

Enteral Feeding In Utero Induces Marked Intestinal Structural and Functional Proteome Changes in Pig Fetuses

Intestinal adaptation from parenteral to enteral nutrition is crucial for survival and growth of newborns. Rapid feeding-induced gut maturation occurs immediately after birth in both preterm and term neonates, but it remains unclear whether the responses depend on factors related to birth transition (e.g. bacterial colonization, endocrine, and metabolic changes). We hypothesized that enteral feeding matures the immature intestine, even in fetuses before birth. Hence, control pig fetuses were compared with fetuses fed with milk formula for 24 h in utero. Gel-based proteomics showed that feeding-induced changes in 38 proteins, along with marked increases in intestinal mass and changes in activities of brush border enzymes. Physiological functions of the identified proteins were related to enterocyte apoptosis (e.g. caspase 1) and nutrient metabolism (e.g. citric acid cycle proteins). Many of the differentiated proteins were similar to those identified previously in preterm pigs fed with the same formula after birth, except that effects on proteins related to inflammatory lesions (e.g. heat shock proteins) were absent. Our results show that enteral feeding, independently of the birth transition, induces marked gut maturation and proteome change in the immature intestine. Hence, immediate postnatal feeding-induced gut changes are largely independent of factors related to the birth transition.

Intestinal proteome changes during infant necrotizing enterocolitis

Background:Changes in the intestinal and colonic proteome in patients with necrotizing enterocolitis (NEC) may help to characterize the disease pathology and identify new biomarkers and treatment targets for NEC.Methods:Using gel-based proteomics, proteins in NEC-affected intestinal and colonic sections were compared with those in adjacent, near-normal tissue sections within the same patients. Western blot and immunohistochemistry were applied to crossvalidate proteomic data and histological location of some selected proteins.Results:Thirty proteins were identified with differential expression between necrotic and vital small-intestine sections and 23 proteins were identified for colon sections. Five proteins were similarly affected in the small intestine and colon: histamine receptors (HRs), actins, globins, immunoglobulin, and antitrypsin. Two heat shock proteins (HSPs) were affected in the small intestine. Furthermore, proteins involved in antioxidation, angiogenesis, cytoskeleton formation, and metabolism were affected. Finally, secretory proteins such as antitrypsin, fatty-acid binding protein 5, and haptoglobin differed between NEC-affected and vital tissues.Conclusion:NEC progression affects different pathways in the small intestine and colon. HSPs may play an important role, especially in the small intestine. The identified secretory proteins should be investigated as possible circulating markers of NEC progression in different gut regions.

Premature delivery reduces intestinal cytoskeleton, metabolism, and stress response proteins in newborn formula-fed pigs.

Objective: Preterm infants often show intolerance to the first enteral feeds, and the structural and functional basis of this intolerance remains unclear. We hypothesized that preterm and term neonates show similar gut trophic responses to feeding but different expression of intestinal functional proteins, thus helping to explain why preterm neonates are more susceptible to feeding-induced disorders such as necrotizing enterocolitis (NEC). Methods: Incidence of feeding-induced NEC, intestinal mass, and brush border enzyme activities, and the intestinal proteome in preterm cesarean-delivered pigs were compared with the corresponding values in pigs delivered spontaneously at term. Results: For both preterm and term pigs, mucosal mass and maltase activity increased (50%–100%), whereas lactase decreased (−50%), relative to values at birth. Only preterm pigs were highly NEC sensitive (30% vs 0% in term pigs, P < 0.05). By gel-based proteomics, 36 identified proteins differed in expression, with most proteins showing downregulation in preterm pigs, including proteins related to intestinal structure and actin filaments, stress response, protein processing, and nutrient metabolism. Conclusions: Despite that enteral feeding induces rapid gut tropic response in both term and preterm neonates, the expression level of cellular proteins related to mucosal integrity, metabolism, and stress response differed markedly (including complement 3, prohibitin, ornithine carbamoyltransferase, and arginosuccinate synthetase). These proteins may play a role in the development of functional gut disorders and NEC in preterm neonates.

Polysaccharopeptide mimics ciclosporin-mediated Th1/Th2 cytokine balance for suppression of activated human T cell proliferation by MAPKp38 and STAT5 pathways.

The activation of T helper (Th) cell subsets plays an important role in the human immune system. Uncontrolled Th1 and Th2 responses lead to autoimmune and inflammatory diseases, respectively. The identification of agents that modulate the Th1/Th2 cytokines is therefore essential for controlling these diseases. We recently reported that polysaccharopeptide (PSP) from Coriolus versicolor exhibited ciclosporin-like activities to control aberrant T lymphocyte activation. Here, we compared the properties of PSP with ciclosporin on cell proliferation, CD25+ expression, secretion of Th1/Th2 cytokines and activation of mitogen-activated protein kinase (MAPK)p38 and signal transducers and activators of transcription 5 (STAT5) on T cells. The data show that PSP alone suppresses the proliferation of activated T cells. PSP exhibited similar and additive inhibitory effects to ciclosporin to suppress activated T cell proliferation, Th1 cytokines and reduce CD3+/CD25+ cell expression, but not Th2 cytokine expression, which helps the cytokine balance shift towards Th2 dominance. These suppressive actions of PSP involved the MAPKp38 and STAT5 pathways. These findings refine our understanding of the effects of PSP on T lymphocytes and its adjuvant properties with the immunosuppressant ciclosporin for possible control of autoimmune diseases.