X-Message-Number: 30412 Date: Mon, 4 Feb 2008 20:57:07 -0800 (PST) From: Subject: Green tea polyphenols induce freeze tolerance [Some cryoprotectants, such as dimethylsulfoxide have shown strong reduction in freezing damage at concentrations too low to significantly reduce ice formation. Much of the effect of this cryoprotectant thus must be due to other effects, which I will term "freeze tolerance". It is commonly believed that only vitrification or complete ice crystal formation suppression can completely preserve organ functionality. However the only existing animal model of survival at dry ice temperatures is Canada's woollybear caterpillar. This caterpillar is known not to vitrify, so its ability to survive at temperatures below the glass transition must be due to freeze tolerance. The result of billions of years of evolution in the form of this hardy Arctic animal implies that vitrification is not neccessary for full recovery from below glass transition temperatures. Green tea polyphenols are an example of an additive that can induce freeze tolerance. Below, 500 mug of green tea polyphenol (GTP) offered protection against freeze-thaw damage that was slightly superior to that offered by 10% (v/v) dimethylsulfoxide. Moreover, NO morphological alterations were noted when both GTP and dimethylsulfoxide were added. The woolybear caterpillar cryopreservation secret thus may no longer be a complete mystery. Green tea polyphenols possess the additional property of reducing ethylene glycol and glycerol toxicity, as well as probably reducing the toxicity of other cryoprotectants as well. GTP may aid current vitrification solutions, both by reducing cryoprotectant toxicity, as well as by lowering the absolute amount of cryoprotectants needed as well, since complete vitrification would hopefully no longer be required. The major limitation in the use of this inexpensive additive is its relatively poor permeation into tissue. This can be partially corrected by the use of liposomes, and/or terpenes. However, until this permeation issue is fully resolved duplicating the woolybear caterpillar's amazing feat of survival at ultra-low temperatures without vitrification will remain -just- out of reach.] Biotechnol Lett. 2005 May;27(9):655-60. Protection of osteoblastic cells from freeze/thaw cycle-induced oxidative stress by green tea polyphenol. Han DW, Kim HH, Lee MH, Baek HS, Lee KY, Hyon SH, Park JC. Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-752, Korea. Green tea polyphenol (GTP) together with dimethylsulphoxide (DMSO) were added to a freezing solution of osteoblastic cells (rat calvarial osteoblasts and human osteosarcoma cells) exposed to repeated freeze/thaw cycles (FTC) to induce oxidative stress. When cells were subjected to 3 FTCs, freezing medium containing 10% (v/v) DMSO and 500 mug GTP ml(-1) significantly (p<0.05) suppressed cell detachment and growth inhibition by over 63% and protected cell morphology. Furthermore, the alkaline phosphatase activity of osteoblastic cells was appreciably maintained after 2 and 3 FTCs in this mixture. Polyphenols may thus be of use as a cell cryopreservant and be advantageous in such fields as cell transplantation and tissue engineering. PMID: 15977073 [Catechin, a constituent of green tea, completely blocked all morphological alterations caused by a 50% glycerol solution.] Pharmacol Res. 2003 Nov;48(5):503-9. Catechin, a natural antioxidant protects against rhabdomyolysis-induced myoglobinuric acute renal failure. Chander V, Singh D, Chopra K. Pharmacology Division, University Institute of Pharmaceutical Sciences (U.I.P.S.), Punjab University, Chandigarh 160014, India. Rhabdomyolysis-induced myoglobinuric acute renal failure accounts for about 10-40% of all cases of acute renal failure (ARF). Reactive oxygen intermediates have been demonstrated to play an etiological role in myoglobinuric renal failure. This study was performed to explore the protective effect of catechin-a natural antioxidant in an experimental model of myoglobinuric ARF in rats. Four groups of rats were employed in this study, group 1 served as control, group 2 was given 50% glycerol (8 ml kg(-1), i.m.), group 3, glycerol plus catechin (40 mg kg(-1), p.o. for 4 days, twice a day) and group 4 was given only catechin (40 mg kg(-1), p.o.), respectively. Renal injury was assessed by measuring serum creatinine, blood urea nitrogen (BUN), creatinine, and urea clearance. The oxidative stress was measured by renal malondialdehyde (MDA) levels, reduced glutathione levels and by enzymatic activity of catalase, glutathione reductase (GR) and superoxide dismutase (SOD). Glycerol administration resulted in a marked renal oxidative stress, significantly deranged the renal functions as well as renal morphology. All these factors were significantly improved by catechin treatment. Catechin, due to its antioxidative activity, reduced the toxicity of myoglobin in the renal tissues, and thus exerted a renoprotective effect in this rhabdomyolysis mimicking model. PMID: 12967597 [Green tea reduces ethylene glycol toxicity.] J Urol. 2005 Jan;173(1):271-5. Preventive effects of green tea on renal stone formation and the role of oxidative stress in nephrolithiasis. Itoh Y, Yasui T, Okada A, Tozawa K, Hayashi Y, Kohri K. Department of Surgical Medicine, Nephro-urology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya City, Aichi 467-8601, Japan. PURPOSE: Urinary stones are similar to arteriosclerosis in epidemiology, mechanism, calcification composition and age at frequent occurrence. The calcification that occurs in arteriosclerosis is inhibited by antioxidants. Green tea leaves contain approximately 13% catechins, which have been shown to have antioxidant effects. We investigated the inhibitory, antioxidative effects of green tea on calcium urinary stone formation. MATERIALS AND METHODS: A total of 120 Wistar rats were divided into 4 groups, namely group 1-control rats receiving saline, group 2-stone group rats administered ethylene glycol (EG) and vitamin D3, group 3-drink group rats administered EG, vitamin D3 and green tea given as drinking water, and group 4-powder group rats administered EG, vitamin D3 and 2.5% powdered green tea leaves mixed in a powder diet. Pooled 24-hour urine samples and blood samples were collected and the 2 kidneys were excised 7, 14 and 21 days after administration, respectively. One kidney was used for immunohistological examination of osteopontin, superoxide dismutase (SOD), p65, p53 and bcl-2 expression, in situ hybridization of osteopontin and detection of apoptosis, while the other was used for quantitative analysis of SOD activity. RESULTS: Green tea treatment decreased urinary oxalate excretion and calcium oxalate deposit formation. Green tea treatment increased SOD activity compared with the stone group. The degree of apoptosis in the stone group was significantly increased compared with the drink and powder groups. CONCLUSIONS: The inhibitory effect of green tea on calcium oxalate urolithiasis is most likely due to antioxidative effects. PMID: 15592095 [The major limitation in the use of green tea polyphenols is their poor permeation into tissue.] J Neurosci Methods. 2005 Jun 30;145(1-2):255-66. Optimal conditions for peripheral nerve storage in green tea polyphenol: an experimental study in animals. Matsumoto T, Kakinoki R, Ikeguchi R, Hyon SH, Nakamura T. Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan. Our previous study demonstrated successful peripheral nerve storage for 1 month using polyphenol solution. We here report two studies to solve residual problems in using polyphenols as a storage solution for peripheral nerves. Study 1 was designed to determine the optimal concentration of the polyphenol solution and the optimal immersion period for nerve storage. Rat sciatic nerve segments were immersed in polyphenol solution at three different concentrations (2.5, 1.0, and 0.5 mg/ml) for three different periods (1, 7, and 26 days). Electrophysiological and morphological studies demonstrated that nerve regeneration from nerve segments that had been immersed in 1mg/ml polyphenol solution for 1 week and in Dulbecco's modified Eagle's medium (DMEM) for the subsequent 3 weeks was superior to the regeneration in other treatment groups. In study 2, the permeability of nerve tissue to polyphenol solution was investigated using canine sciatic nerve segments stored in 1.0mg/ml polyphenol solution for 1 week and in DMEM for the subsequent 3 weeks. Electron microscopy revealed that the Schwann cell structure within 500-700 microm of the perineurium was preserved, but cells deeper than 500-700 microm were badly damaged or had disappeared. The infiltration limit for polyphenol solution into neural tissue is inferred to be 500-700 microm. PMID: 15922041 Int J Pharm. 2006 Mar 9;310(1-2):131-8. Epub 2006 Jan 18. Enhancement of the transdermal delivery of catechins by liposomes incorporating anionic surfactants and ethanol. Fang JY, Hwang TL, Huang YL, Fang CL. Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, 259 Wen-Hua 1st Road, Kweishan, Taoyuan 333, Taiwan. The aim of this study was to develop and evaluate liposomal formulations encapsulating tea catechins, which possess antioxidant and chemopreventive activities. Liposomes were characterized for size, zeta potential, and entrapment efficiency. Both in vitro and in vivo skin permeation were examined using nude mouse skin as a model. The results suggested that the liposomal composition plays an important role in affecting the efficiency of transdermal catechin delivery. Incorporation of anionic surfactants such as deoxycholic acid (DA) and dicetyl phosphate (DP) in the liposomes in the presence of 15% ethanol increased the (+)-catechin permeation by five to seven-fold as compared to the control. The flexibility of bilayers is suggested as an important factor governing the enhancing effect of liposomes. Intercellular spaces within the stratum corneum but not shunt routes are the major pathways for catechin delivery from liposomes. (+)-Catechin and (-)-epicatechin are isomers which showed similar encapsulation efficiencies and skin permeation in liposomes. (-)-Epigallocatechin-3-gallate showed the highest encapsulation rate and in vivo skin deposition level in liposomes among all catechins tested. The stability and in vitro tranepidermal water loss test indicated the safety of the practical use of liposomes developed in this study. PMID: 16413711 Biol Pharm Bull. 2007 Feb;30(2):343-9. Transdermal delivery of tea catechins and theophylline enhanced by terpenes: a mechanistic study. Fang JY, Tsai TH, Lin YY, Wong WW, Wang MN, Huang JF. Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan. Using in vitro and in vivo techniques, terpenes were evaluated as enhancers to improve the skin permeation of therapeutically active agents derived from tea, including tea catechins and theophylline. The in vitro permeation was determined by Franz cells. The skin deposition and subcutaneous amounts of drugs sampled by microdialysis were evaluated in vivo. Terpenes varied in their activities of enhancing drug permeation. The oxygen-containing terpenes were effective enhancers of drug permeation, whereas the hydrocarbon terpenes were much less efficient. Oxygen-containing terpenes with a bicyclic structure had reduced enhancing activity. Terpenes enhanced tea catechin permeation to a much greater degree than they did theophylline. The isomers of (+)-catechin and (-)-epicatechin showed different permeation behaviors when incorporated with terpenes. In the in vivo status, terpenes promoted the skin uptake but not the subsequent subcutaneous concentration of (-)-epigallocatechin gallate (EGCG). Both increased skin/vehicle partitioning and lipid bilayer disruption of the stratum corneum (SC) contributed the enhancing mechanisms of terpenes for topically applied tea catechins and theophylline based on the experimental results from the partition coefficient and transepidermal water loss (TEWL). alpha-Terpineol was found to be the best enhancer for catechins and theophylline. The high enhancement by alpha-terpineol was due to macroscopic perturbation of the SC and the biological reaction in viable skin as evaluated by TEWL and colorimetry. PMID: 17268077 [The nature of glycerol induced toxicity has never been convincingly explained by cryobiologists. However the main cause of glycerol toxicity has been known for over a decade according to claims by toxicologists, who apparently never talk to cryobiologists! Glycerol induced toxicity is reputed to be largely mediated by iron, since iron chelators like catechin, naringin, etc can completely block glycerol induced morphological alterations.] Drug Metab Rev. 1999 Nov;31(4):971-97. Oxidant mechanisms in toxic acute renal failure. Baliga R, Ueda N, Walker PD, Shah SV. University of Mississippi Medical Center, Jackson 39216, USA. Over the last decade, there is accumulating evidence for a role of reactive oxygen metabolites in the pathogenesis of a variety of renal diseases, including gentamicin, glycerol, cisplatin, and cyclosporine A models of toxic acute renal failure. Gentamicin has been shown both in in vitro and in vivo studies to enhance the generation of reactive oxygen metabolites. Iron is important in models of tissue injury, presumably because it is capable of catalyzing free-radical formation. Gentamicin has been shown to cause release of iron from renal cortical mitochondria. Scavengers of reactive oxygen metabolites as well as iron chelators provide protection in gentamicin-induced nephrotoxicity. In glycerol-induced acute renal failure, an animal model of rhabdomyolysis, there is enhanced generation of hydrogen peroxide, and scavengers of reactive oxygen metabolites and iron chelators provide protection. Although the dogma is that the myoglobin is the source of iron, recent studies suggest that cytochrome P450 may be an important source of iron in this model. In addition, there are marked alterations in antioxidant defenses, such as glutathione, as well as changes in heme oxygenase. Several recent in vitro and in vivo studies indicate an important role of reactive oxygen metabolites in cisplatin-induced nephrotoxicity. Thus, catalytic iron is increased both in vitro and in vivo by cisplatin, and iron chelators as well as hydroxyl radical scavengers have been shown to be protective. Recent studies indicate that cytochrome P450 may also be an important source of the catalytic iron in cisplatin nephrotoxicity. Cyclosporine A has been shown to enhance generation of hydrogen peroxide in vitro and enhance lipid peroxidation in vitro and in vivo. Antioxidants have been shown to be protective in cyclosporine A nephrotoxicity. This collective body of evidence suggests an important role for reactive oxygen metabolites in toxic acute renal failure and may provide therapeutic opportunities of preventing or treating acute renal failure in humans. PMID: 10575556 [Tea polyphenols may reduce cryoprotectant toxicity by, for example chelating calcium to reduce ethylene glycol toxicity, and chelating iron to reduce glycerol toxicity. Propylene glycol and dimethysulfoxide release even more intracellular calcium than ethylene glycol does, so calcium chelation probably would reduce their toxicity as well.] Biol Trace Elem Res. 1998 Oct;65(1):75-86. Effect of green tea and black tea on the metabolisms of mineral elements in old rats. Zeyuan D, Bingying T, Xiaolin L, Jinming H, Yifeng C. Institute of Food Nutrition, Nanchang University, China. A 2-mo experiment with the white Sprague-Dawley (SD) rats was conducted to investigate the effect of the water extracts of black tea (BTWE) and green tea (GTWE) and the black tea leaves (BTF) and the green tea leaves (GTF) on the metabolism of mineral elements. One hundred eight 12-mo-old white SD rats were randomly divided into 13 groups; 6 of these drank the BTWE or GTWE in which the water extracts concentrations of black tea or green tea were, respectively, 0.6%, 1.2%, and 2.4%, and 6 of these had black tea leaves (BTF) and green tea leaves (GTF) added in which the contents of BTF or GTF were, respectively, 0.5%, 1.0%, and 2.0%, one of these was control. The teas and their water extracts could promote the absorption of manganese and copper. In GTF, BTF, GTWE, and BTWE, the apparent absorption rates of manganese were significantly increased. The manganese contents in the tibia were also elevated, and the differences between GTWE and GTF were significant. The apparent absorption rates of copper and the copper contents in the tibia were increased, but not significantly. The teas and their water extracts inhibited the absorption of calcium (p > 0.05) and iron (p < 0.05). The cerebrum calcium contents were significantly decreased, but the contents of calcium and iron in tibia were not significantly changed. Compared with the control, although the apparent absorption rates of aluminum in all experimental groups were not observed to be different, the aluminum contents in the tibia (p > 0.05) and cerebrum (p < 0.05) were increased. GTF and GTWE decreased the apparent absorption rates of zinc, but BTF and BTWE increased them; the zinc contents in tibia were a little improved, whereas its contents in the cerebrum were gradually decreased with the increase of tea leaves dose and tea concentration. PMID: 9877538 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=30412