| In vitro: |
| Cytotechnology, 2010, 62(3):225-233. | | Effects of sulfur amino acids, L: -methionine, L: -cystine and L: -cysteine on lipoprotein lipase and hormone-sensitive lipase in differentiated mouse 3T3-L1 adipocytes.[Reference: WebLink] |
Rats subcutaneously implanted with AH109A hepatoma cells show hyperlipidemia with high concentrations of serum triglyceride and nonesterified fatty acid, suppression of lipoprotein lipase (LPL), and elevation of hormone-sensitive lipase (HSL) activities during the growth of the hepatoma. Supplementation of the diet with sulfur amino acids such as L -methionine (Met) and L-Cystine (Cys) improved hyperlipidemia by restoring LPL and HSL activities.
METHODS AND RESULTS:
In the present study, we have attempted to examine the effects of sulfur amino acids on the activity and mRNA level of LPL and the activity of HSL using 3T3-L1 cells, which are known to differentiate to adipocytes. The adipocytes were incubated with various concentrations of Met, Cys or L -cysteine (CysH) in the absence or presence of tumor necrosis factor-alpha (TNF-alpha). LPL activity was suppressed by TNF-alpha. In the absence of TNF-alpha, Met, Cys and CysH did not change the LPL activity. In the presence of TNF-alpha, Met and Cys significantly increased the LPL activity, and Met also enhanced the LPL mRNA level. HSL activity was also suppressed by TNF-alpha. In the absence of TNF-alpha, Met enhanced the HSL activity. In the presence of TNF-alpha, Met, Cys and CysH suppressed the HSL activity. Sulfur amino acids such as Met, Cys and CysH affected the LPL activity, mRNA level, and HSL activity in 3T3-L1 adipocytes.
CONCLUSIONS:
Some of these effects of sulfur amino acids were different between LPL and HSL, between the absence and the presence of TNF-alpha, and between 3T3-L1 adipocytes and the adipose tissue from rats. |
|
| In vivo: |
| Geriatrics & Gerontology International, 2010, 8(4):243-250. | | Co-administration of L-cystine and L-theanine enhances efficacy of influenza vaccination in elderly persons: Nutritional status-dependent immunogenicity.[Reference: WebLink] | The immune response to influenza vaccine is attenuated in elderly persons, though they are at greatest risk for morbidity and mortality by influenza virus infection.
METHODS AND RESULTS:
Experimental studies demonstrate that co-administration of L-Cystine and l-theanine enhanced antigen-specific production of immunoglobulin in aged mice infected with influenza virus. We thus investigated the effect of L-Cystine and l-theanine on antibody induction by influenza vaccines in elderly persons. Residents in a nursing home were randomly allocated to L-Cystine and l-theanine (n = 32) or placebo (n = 33). The test substances were administered p.o. for 14 days before immunization. Serum influenza virus antibody titers were measured before and 4 weeks after vaccination. Vaccination significantly elevated hemagglutination inhibition (HI) titers for all the three strains of influenza viruses (A/New Caledonia [H1N1], A/New York [H3N2] and B/Shanghai) in both groups. HI titers after vaccination were not significantly different between the two groups for either strain. Also, the seroconversion rate was not significantly different between the two groups in the aggregate. A stratified analysis showed that the rate of seroconversion was significantly greater in the L-Cystine and l-theanine group compared with the placebo group for influenza virus A (H1N1) among subjects with low serum total protein (63% vs 10%, P < 0.05) or low hemoglobin (71% vs 9%, P < 0.05).
CONCLUSIONS:
Co-administration of L-Cystine and l-theanine before vaccination may enhance the immune response to influenza vaccine in elderly subjects with low serum total protein or hemoglobin. | | Toxicology Letters, 1992, 60(1):75-82. | | Effect of l-cystine on toxicity of paraquat in mice.[Reference: WebLink] |
METHODS AND RESULTS:
The protective effect of L-Cystine on the toxicity of paraquat (PQ) in mice was studied. Lipid peroxidation in the lung significantly increased after oral administration of PQ (200 mgkg) and the increase in lipid peroxidation was prevented by L-Cystine treatment (300 mgkg). PQ administration produced an increase in Superoxide dismutase (SOD) activity and a decrease in glutathione peroxidase (GSH-Px) activity in the lung at 24 h after PQ. L-Cystine treatment significantly prevented the changes in SOD and GSH-Px activity in the lung after PQ. L-Cystine treatment prevented the decrease in non-protein sulfhydryl (NP-SH) content in the lung after PQ administration. The tissue distribution and excretion of PQ after PQ administration were not changed by L-Cystine treatment. Plasma aspartate aminotransferase activity did not change after PQ administration.
CONCLUSIONS:
These results suggest that L-Cystine protects against the toxicity of PQ by maintaining reduced glutathione levels in the cells. |
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