Dysregulated expression of arginine metabolic enzymes in human intestinal tissues of necrotizing enterocolitis and response of CaCO2 cells to bacterial components.

The small intestine is the exclusive site of arginine synthesis in neonates. Low levels of circulating arginine have been associated with the occurrence of necrotizing enterocolitis (NEC) but the mechanism of arginine dysregulation has not been fully elucidated. We aimed to investigate (i) expressional changes of arginine synthesizing and catabolic enzymes in human intestinal tissues of NEC, spontaneous intestinal perforation (SIP) and noninflammatory surgical conditions (Surg-CTL) and to investigate the (ii) mechanisms of arginine dysregulation and enterocyte proliferation upon stimulation by bacterial components, arginine depletion, ARG1 overexpression and nitric oxide (NO) supplementation. Our results showed that expressions of arginine synthesizing enzymes ALDH18A1, ASL, ASS1, CPS1, GLS, OAT and PRODH were significantly decreased in NEC compared with Surg-CTL or SIP tissues. Catabolic enzyme ARG1 was increased (>100-fold) in NEC tissues and histologically demonstrated to be expressed by infiltrating neutrophils. No change in arginine metabolic enzymes was observed between SIP and Surg-CTL tissues. In CaCO2 cells, arginine metabolic enzymes were differentially dysregulated by lipopolysaccharide or lipoteichoic acid. Depletion of arginine reduced cell proliferation and this phenomenon could be partially rescued by NO. Overexpression of ARG1 also reduced enterocyte proliferation. We provided the first expressional profile of arginine metabolic enzymes at the tissue level of NEC. Our findings suggested that arginine homeostasis was severely disturbed and could be triggered by inflammatory responses of enterocytes and infiltrating neutrophils as well as bacterial components. Such reactions could reduce arginine and NO, resulting in mucosal damage. The benefit of arginine supplementation for NEC prophylaxis merits further clinical evaluation.

Prospective self-controlled trial of the efficacy and tolerability of a herbal syrup for young children with eczema.

OBJECTIVES: Traditional Chinese medicine (TCM) is popular as an alternative medicine in children with atopic dermatitis (AD). A concoction of five herbs in a capsular preparation has been confirmed to be efficacious in improving the quality of life and sparing topical corticosteroid usage. We evaluated the clinical efficacy and tolerability of the same concoction in syrup form. METHODS: This was a prospective self-controlled trial set in the pediatric dermatology clinic of a teaching hospital. Children aged 4-7 years with moderate-to-severe AD received 20 ml of TCM syrup daily. Clinical parameters and laboratory markers were measured before and at 2 weeks, 7 weeks and 12 weeks of treatment, and at 4 weeks after completion. Disease severity was evaluated by the SCORing Atopic Dermatitis (SCORAD) index and quality of life by the Children's Dermatology Life Quality Index (CDLQI). Blood was obtained for a complete blood count, total IgE, eosinophil count, and biochemical studies prior to and after 3 months of TCM usage. RESULTS: Twenty-two patients participated in the study. There were significant improvements in the objective SCORAD, pruritus and CDLQI scores 4 weeks after study completion. There was no change in sleep score or amount of topical steroid consumption. No biochemical evidence of any adverse drug reaction was observed during the study period. The TCM syrup was generally palatable and well tolerated by the children. Adverse effects were generally mild but two patients with rash withdrew during the study. CONCLUSION: The palatability means that further evaluations and dosage studies of the concoction will be possible in young children.

Pro-oxidative effects of Chinese herbal medicine on G6PD-deficient erythrocytes in vitro.

Glucose-6-phosphate dehydrogenase (G6PD)-deficient subjects are susceptible to chemical-induced oxidative haemolysis. Little is known concerning the haemolytic properties of Chinese herbal medicine on G6PD-deficient subjects. Our objective was to investigate the pro-oxidative effect of 18 commonly used Chinese herbal medicine (CHM) on human G6PD-deficient red blood cells. G6PD-deficient (n=10) and normal (n=10) whole blood samples were incubated with water extracts of CHM. The resulting levels of reduced glutathione (GSH) and methaemoglobin (MetHb) were determined by biochemical assays. Rhizoma Coptidis significantly reduced GSH level by 48.9+/-5.4% (at 1 mg/mL) in the G6PD-deficient erythrocytes (P<0.001) compared with the respective control group without challenge. Similar dose-dependent responses were observed at higher concentrations of Cortex Moutan, Radix Rehmanniae, Radix Bupleuri, Rhizoma Polygoni Cuspidati and Flos Chimonanthi (P<0.01, 5-10 mg/mL). In addition, the levels of MetHb were elevated significantly when challenged with Rhizoma Coptidis (2.8 fold at 5 mg/mL) and Cortex Moutan (3.4 fold at 10 mg/mL). This is the first report on the pro-oxidative action of CHM on G6PD-deficient blood samples in vitro as demonstrated by the decrease of GSH and increase of MetHb. G6PD-deficient subjects should restrain from excessive consumption of these pro-oxidative herbs.

Pro-oxidative effects of tea and polyphenols, epigallocatechin-3-gallate and epigallocatechin, on G6PD-deficient erythrocytes in vitro.

Glucose-6-phosphate dehydrogenase (G6PD)-deficient subjects are vulnerable to chemical-induced hemolysis if exposed to oxidative agents. Recent studies reported that green tea and its constituents might act as pro-oxidants. Our objective was to investigate effects of tea and its polyphenolic components on the oxidative status of human G6PD-deficient erythrocytes. Erythrocytes of G6PD-deficient (n = 8) and normal (n = 8) subjects were incubated with water extracts of 3 types of tea samples (black tea, green tea and decaffeinated green tea extract) and 6 polyphenols. The resulting levels of reduced glutathione (GSH) and glutathione disulphide (GSSG), methemoglobin and plasma hemoglobin were quantified by HPLC and biochemical assays. The tea extracts significantly reduced GSH and increased GSSG levels in G6PD-deficient erythrocytes in a dose-dependent manner (0.5-10 mg/ml), but not in normal erythrocytes. Similar dose-dependent responses to (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG), but not to the other polyphenols, were observed. In G6PD-deficient cells, GSH was reduced by 43.3% (EGC at 0.05 mg/ml) and 33.3% (EGCG at 0.5 mg/ml), compared with pre-challenged levels. The concentration of methemoglobin was increased significantly when challenged with tea extracts, and EGC. Plasma hemoglobin levels were higher in G6PD-deficient samples after exposure to tea extracts, EGCG, EGC and gallic acid, compared with those in normal blood. Tea extracts and polyphenols significantly altered the oxidative status of G6PD-deficient erythrocytes in vitro as demonstrated by the decrease of GSH, and increased GSSG, methemoglobin and plasma hemoglobin. Our data caution against the excessive consumption of concentrated tea polyphenolic products by G6PD-deficient subjects.

Risk of vitamin A toxicity from candy-like chewable vitamin supplements for children.

Numerous vitamin supplements are available over-the-counter to the general public. Some such supplements are available as candy-like chewable preparations to encourage consumption by children. We report 3 cases of overdose of such preparations. Each patient had taken an estimated 200,000 to 300,000 IU of vitamin A. Their circulating vitamin A (retinol and retinyl palmitate) concentrations were monitored over a 6-month period. There were no clinical or biochemical complications noted. However, there were marked increases in both retinol and retinyl palmitate concentrations above age-related reference ranges. In particular, it took 1 to 3 weeks for the serum retinol concentrations to peak and many months for them to normalize. Parents should be warned about the dangers of excessive vitamin consumption. Clinicians should be aware of the late peak in serum retinol concentrations, which may lead to late complications of vitamin A overdose.

Thrombopoietin protects against in vitro and in vivo cardiotoxicity induced by doxorubicin.

BACKGROUND: Doxorubicin (DOX) is an important antineoplastic agent. However, the associated cardiotoxicity, possibly mediated by the production of reactive oxygen species, has remained a significant and dose-limiting clinical problem. Our hypothesis is that the hematopoietic/megakaryocytopoietic growth factor thrombopoietin (TPO) protects against DOX-induced cardiotoxicity and might involve antiapoptotic mechanism exerted on cardiomyocytes. METHODS AND RESULTS: In vitro investigations on H9C2 cell line and spontaneously beating cells of primary, neonatal rat ventricle, as well as an in vivo study in a mouse model of DOX-induced acute cardiomyopathy, were performed. Our results showed that pretreatment with TPO significantly increased viability of DOX-injured H9C2 cells and beating rates of neonatal myocytes, with effects similar to those of dexrazoxane, a clinically approved cardiac protective agent. TPO ameliorated DOX-induced apoptosis of H9C2 cells as demonstrated by assays of annexin V, active caspase-3, and mitochondrial membrane potential. In the mouse model, administration of TPO (12.5 microg/kg IP for 3 alternate days) significantly reduced DOX-induced (20 mg/kg) cardiotoxicity, including low blood cell count, cardiomyocyte lesions (apoptosis, vacuolization, and myofibrillar loss), and animal mortality. Using Doppler echocardiography, we observed increased heart rate, fractional shortening, and cardiac output in animals pretreated with TPO compared with those receiving DOX alone. CONCLUSIONS: These data have provided the first evidence that TPO is a protective agent against DOX-induced cardiac injury. We propose to further explore an integrated program, incorporating TPO with other protocols, for treatment of DOX-induced cardiotoxicity and other forms of cardiomyopathy.