Takatoshi Nagate

Taurine suppresses development of atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits

While the hypocholesterolemic effects of taurine have extensively been studied using experimental animals, the anti-atherosclerotic effects of taurine have been given less attention. We examined the effect of taurine on atherosclerotic lesions in Watanabe heritable hyperlipidemic (WHHL) rabbits. Treatment of WHHL rabbits with taurine (0.3% in drinking tap water) for 24 weeks decreased aortic lesions by 31%, estimated as intimal thickening. Taurine significantly decreased cholesteryl ester content of aortic arch, thoracic aorta, and abdominal aorta by 35, 43, and 54%, respectively. Concomitantly, activity of acyl-CoA:cholesterol acyltransferase (ACAT), an enzyme responsible for cholesterol esterification, was also significantly decreased. Immunohistochemical analysis revealed decreased macrophages in the intima of taurine-treated rabbits. Taurine had no apparent effect on blood pressure and serum cholesterol levels. Contents of thiobarbituric acid reactive substances (TBARS), a marker of lipid peroxidation, was reduced in serum and aorta by 29 and 50%, respectively, when taurine was ingested. In addition, LDL from taurine-treated rabbits was resistant to copper-induced oxidative modification. These results revealed that taurine prevents development of atherosclerosis and that the anti-atherosclerotic effects of taurine are independent of serum cholesterol levels. The anti-oxidant action of taurine may be involved in inhibiting atherosclerosis in these rabbits.

Antibiotic effect of linolenic acid fromChlorococcum strain HS-101 andDunaliella primolecta on methicillin-resistantStaphylococcus aureus

Methanol extracts fromChlorococcum strain HS-101 andDunaliella primolecta strongly inhibited the growth of a strain of methicillin-resistantStaphylococcus aureus (MRSA), which is causing serious problems in Japanese hospitals. So that the anti-MRSA substance(s) could be purified and identified, the growth medium was improved for antibiotic production. When the two strains were cultured in their improved media, antibiotic production byChlorococcum strain HS-101 was 1.8-fold that in the standard BG-11 medium, and production byD. primolecta was 2.3-fold. The activity pattern of fractions eluted by silica-gel or gel-permeation chromatography suggested that both strains produced two antibiotic substances. Identification of the purified substances by NMR and GC-MS showed that one of the active substances in both strains wasα-linolenic acid. Ten fatty acids from other sources were tested, and it was found that unsaturated fatty acids had antibiotic activity against MRSA, with the highest activity that of γ-linolenic acid.

Taurine Inhibits Development Of Atherosclerotic Lesions In apolipoprotein E-Deficient Mice‡

1. The effects of taurine on the development of atherosclerotic lesions were investigated in apolipoprotein (apo) E‐deficient mice, an animal model with severe hypercholesterolaemia and extensive atherosclerosis. These mice were fed a normal laboratory chow containing 2% taurine for 12 weeks.

Heat shock protein (HSP) 47 and collagen are upregulated during neointimal formation in the balloon-injured rat carotid artery.

Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is thought to be essential for the proper processing and secretion of procollagen molecules. We investigated the time course and localization of HSP47 and collagen expression after balloon catheter angioplasty in the rat carotid artery, based on the premise that accumulation of extracellular matrix components is a main feature of intimal hyperplasia in humans and in laboratory animals. Low levels of HSP47 expression were evident in uninjured carotid arteries. Northern blot analysis revealed that HSP47 mRNA expression was markedly stimulated 1--3 days after the induced injury and a high level was maintained for 7 days, followed by a gradual decline for up to 21 days after the injury. These changes in HSP47 expression paralleled changes in alpha 1(I) collagen expression. Immunohistochemical staining revealed colocalization of HSP47 and collagen in smooth muscle cells (SMCs) of the media and intima. In situ hybridization analysis showed that activated SMCs, which proliferated and migrated into the intima, expressed high levels of HSP47. In cultured human aortic SMCs, similar upregulation of HSP47 and alpha1(I) collagen by TGF-beta was noted. These results show that SMCs activated after balloon injury express high levels of HSP47 and collagen during cell proliferation and migration, hence an overproduction of collagen and development of intimal thickening. Thus, HSP47 plays a role in the formation and progression of neointima after angioplasty.

The susceptibility of Campylobacter pylori to antiulcer agents and antibiotics

The antibacterial activities of antiulcer agents and antibiotics against Campylobacter pylori were studied. The MC90 values of three kinds of antibiotics—macrolides, β-lactams, and metronidazole—were 0.05–0.78, 0.39–1.56, and 12.5 μg/ml, respectively. They were more active than antiulcer agents such as H2blockers and cetraxate with MIC90 values of ≥1,600 and >1,600 μg/ml, respectively. Especially, clarithromycin, a new derivative of erythromycin, showed an MIC90 of 0.05 μg/ml. However, the other antiulcer agents such as sofalcone and tripotassium dicitrate bismuthate (TDB) also had MIC90 values of 50 and 6.25 μg/ml, respectively, Clarithromycin, sofalcone, and TDB showed bactericidal activity against C. pylori CLO2. The bactericidal actions of these drugs could be observed under electron microscopy.

Effects of Long-Term Treatment with Taurine in Mice Fed a High -Fat Diet

Hypocholesterolemic effects of taurine in rats fed a high-fat and high-cholesterol diet are well established. However, there are few studies on long-term effects of taurine on cholesterol metabolism. In the present study, taurine was dissolved in drinking water and given to C57BL/6J mice during 6 months-feeding of a high fat diet. Taurinetreatmentsignificantly decreased serum LDL and VLDL cholesterol, while it significantlyincreased serum HDL cholesterol. In the liver, taurine decreased cholesteryl ester contents, accompanied by decrease in acyl Co-A:cholesterol acyltransferase (ACAT) activity. Hepatic activity of cholesterol 7α- hydroxylase, a rate-limiting enzyme for bile acid synthesis, was doubled with taurine. Taurine reduced by 20% thehigh-fat diet-induced arterial lipid accumulation. Thus, taurine prevented elevation of serum and liver cholesterol levels, as possibly related to accelerated cholesterol elimination from the body through the stimulation of bile acid synthesis. Long-term treatment with taurine is beneficial for prevention of hyperchole sterolemia and atherosclerosis.

Anti-Herpes Simplex Virus substances produced by the marine green alga, Dunaliella primolecta

Among 106 microalgae tested, the cytopathic effect (CPE) upon Vero cells of herpes simplex virus, Type 1 (HSV-1) was inhibited by four methanol extracts of Dunaliella bioculata C-523, D. primolecta C-525, Lyngbya sp. M-9 and Lyngbya aerugineo-coerulea M-12. The green alga, D. primolecta, had the highest anti HSV-1 activity, since 10 μg mL-1 of extract from this alga completely inhibited the CPE. This activity was similar to that of acyclovir at the same concentration. We compared anti-viral activities against adeno virus, herpes simplex virus-2 (HSV-2), Japanese Encephalitis and Polio viruses. Only the CPE of HSV-2 was inhibited. Thus, the factor was specific against HSV. The antiviral activity was apparently excited during HSV adsorption and invasion of the cells. We optimized the conditions for anti HSV-1 activity by prolonging the exposure of HSV-1 to the extract. After 2 h, the CPE of even a high titer of HSV-1 (106 TCID50/0.1 mL) was completely inactivated. By use of various chromatographic techniques, three green substances having anti-HSV activity were purified from the algal mass of D. primolecta, and 5 μg mL-1 of this purified substances completely inhibited the CPE. From the analysis of NMR and MS, the chemical structures of the active substances were identified as pheophorbide-like compounds.

Taurine Reduces Atherosclerotic Lesion Development in Apolipoprotein E-Deficient Mine

The effects of dietary taurine on development of atherosclerotic lesions were investigated using apolipoprotein E (apoE)-deficient mice. Taurine added to regular chow at 2% (w/w), was made freely available to mice for 3 months. Severe hypercholesterolemia and development of atherosclerotic lesions occurred in the apo-E-deficient mice. Taurine treatment decreased the area of Oil red-O positive lipid accumulation in the aortic valve by 31%. In contrast, taurine significantly increased serum atherogenic lipoproteins (LDL + VLDL), without changing HDL cholesterol levels. Although the levels of serum thiobarbituric acid reactive substances (TBARS) in apoE-deficient mice were significantly higher than in wild-type mice, taurine decreased TBARS by 26%. These observations mean that taurine prevents the development of atherosclerosis, independent of serum cholesterol levels. We suggest that antioxidative actions may be involved in the anti-atherosclerotic effects of taurine.

Lipid composition and fatty acid analysis ofHelicobacter pylori

Lipids extracted fromHelicobacter pylori were separated into lipid classes by thin-layer chromatography. SimpleH. pylori lipids consisted of cholesterol esters, triglycerides, free fatty acids, cholesterol, diacylglycerols, and monoacylglycerols. Fatty acids were released from each lipid class by acid methanolysis, and analyzed by gas liquid chromatography and mass spectrometry. Unique methoxy fatty acids, including 11-methoxy heptadecanoic and 11-methoxy nonadecanoic acids, were the major components of the cholesterol esters and triglycerides. The predominance of methoxy fatty acids in the cholesterol esters ofH. pylori may contribute to the acid-resistant characteristic of this bacillus.

Lipid Analysis of helicobacter pylori

Lipids from Helicobacter pylori were extracted, isolated by conventional DEAE-Sephadex and silica gel column chromatography, and then purified by preparative thin-layer chromatography. Simple and phospholipids were analyzed by HPTLC and quantitatively determined by densitometry scanning. The fatty acid compositions of simple lipids were estimated by gas-liquid chromatography. The simple lipid composition of H. pylori consisted of wax ester (2.5%), triglycerides (4.9%), free fatty acids (30.0%), cholesterol (6.9%), diacylglycerol (29.1%), and monoacylglycerol (2.6%). The neutral phospholipid composition consisted of phosphatidyl ethanolamine (79.1%), lysophosphatidyl ethanolamine (16%), and phosphatidyl choline (1.9%). That of acidic phospholipids consisted of phosphatidic acid (52.7%) and phosphatidyl serine (47.3%). The major fatty acids of crude lipid, wax, free fatty acids, triglycerides, diacylglycerides, and monoacyl glycerides were C19:1 (cyclo), C18:2, C16:0, C19:1 (cyclo), C22h:0, and C18:0, respectively. These results are new findings and suggest significant characteristics from the metabolic, physiologic, and chemotaxonomic point of view.