Effects of taurine supplementation on bone mineral density in ovariectomized rats fed calcium deficient diet.
Taurine supplementation has been shown to have a beneficial effect on femur bone mineral content in ovariectomized rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on ovariectomized rats fed calcium deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups. One group was OVX and the other group received sham operation (SHAM), and received either control diet or a taurine supplemented diet for 6 weeks. All rats were fed on calcium deficient diet (AIN-93: 50% level of calcium) and deionized water. Bone mineral density (BMD) and bone mineral content (BMC) were measured in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. Bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Urinary calcium and phosphorus excretion, osteocalcin in blood and cross link value were not significantly different among the groups. Within the OVX group, the taurine supplemented group had not higher femur bone mineral content than the control group. This study established the need for a study on the taurine effect on bone with different calcium levels.
Nutr Res Pract 2009
PMID: 20016710 | Free Full Text
This experiment was originally designed to test the ability of a taurine supplement to minimize bone loss during postmenopausal model with low calcium intake. Sulfur is predominantly responsible for determining the net endogenous acid production from protein because it is the acid precursor that is oxidized to sulfuric acid (Frassetto et al., 1998). It would therefore make sense that a dietary supplement with excess sulfur-containing amino acids (taurine) could yield increased sulfuric acid production in the body. However, these data suggest that bone mineral density per weight was increased, without changes in bone resorption and bone formation, in the taurine supplemented group, and therefore have the potential to increase bone mineral density if either the study is extended or more taurine is supplemented. The beneficial effect of taurine on ovariectomized rats fed calcium deficient diet was not reproduced. Because in this study, the control and taurine groups consumed identical diets as in the previous study (besides the calcium content), and we do not know whether intestinal calcium absorption will be increased by more taurine supplement. These results indicate that no significant differences in spine and femur BMD were found due to 2% taurine diet in OVX rats fed calcium deficient diet for 6 weeks. No positive effects of taurine on bone mineral density were found in the present study. Our failure to see an association between taurine supplementation and bone mineral density may have been related to the fact that we used calcium deficient diet and the same amount of taurine. Further investigations of the relation between taurine and calcium intake level for bone mineral density are warranted.
Effect of dietary taurine and arginine supplementation on bone mineral density in growing female rats.
The purpose of this study was to determine the effect of arginine or -taurine alone and taurine plus arginine on bone mineral density (BMD) and markers of bone formation and bone resorption in growing female rats. Forty female SD rats (75 ± 5 g) were randomly divided into four groups (control, taurine, arginine, taurine + arginine group) and treatment lasted for 9 weeks. All rats were fed on a diet and deionized water. BMD and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase concentrations, and the bone resorption rate was measured by deoxypyridinoline cross-links. Femur BMD was significantly increased in the group with taurine supplementation and femur BMC/weight was significantly increased in the group with arginine + taurine supplementation. Rats fed an arginine or taurine supplemental diet increased femur BMD or femur BMC, but a taurine + arginine-supplemented diet does not have a better effect than arginine or taurine alone in the spine BMD. The femur BMC, expressed per body weight, was higher in arginine + taurine group than in the taurine or arginine group. The results of this study suggest that taurine + arginine supplementation may be beneficial on femur BMC in growing female rats. Additional work is needed to clarify the interactive effects between the taurine and arginine to determine whether dietary intakes of arginine and taurine affect bone quality in growing rats.
Choi MJ, Chang KJ
Adv. Exp. Med. Biol. 2013
Stimulation of ERK2 by taurine with enhanced alkaline phosphatase activity and collagen synthesis in osteoblast-like UMR-106 cells.
Taurine is present in a variety of tissues and exhibits many important physiological functions in the cell. Even though its functions are well documented in many tissues, its actions on bone cells are largely unknown. Considering a recent finding that taurine is present in the bone, we wished to determine if taurine could have any effects on osteoblast cells. Taurine (10 mM) stimulated alkaline phosphatase activity as well as collagen synthesis. Taurine also stimulated tyrosine phosphorylation of a number of cellular proteins including a 42-kDa protein. The 42-kDa protein was identified as extracellular signal regulated protein kinase 2 (ERK2). A mitogen-activated protein kinase kinase (MEK) inhibitor blocked the taurine-stimulated alkaline phosphatase activity and collagen synthesis. These results suggest that taurine could regulate osteoblast metabolism via ERK2 activation.
Park S, Kim H, Kim SJ
Biochem. Pharmacol. Oct 2001
Taurine promotes connective tissue growth factor (CTGF) expression in osteoblasts through the ERK signal pathway.
Taurine is found in bone tissue, but its function in skeletal tissue is not fully understood. The present study was undertaken to investigate regulation of gene expression of connective tissue growth factor (CTGF), and the roles of mitogen-activated protein kinases (MAPKs) in murine osteoblast MC3T3-E1 cells treated with taurine. Western blot analysis showed taurine stimulated CTGF protein secretion in a dose- and time-dependent manner. Taurine induced activation of extracellular signal-regulated kinase (ERK), but not p38 and c-jun N-terminal Kinase (JNK), in osteoblasts. Furthermore, pretreatment of osteoblasts with the ERK inhibitor PD98059 abolished the taurine-induced CTGF production. These data indicate that taurine induces CTGF secretion in MC3T3-E1 cells mediated by the ERK pathway, and suggest that osteoblasts are direct targets of taurine.
Yuan LQ, Lu Y, Luo XH, Xie H…
Amino Acids 2007
Taurine increases cell proliferation and generates an increase in [Mg2+]i accompanied by ERK 1/2 activation in human osteoblast cells.
Taurine has been reported to influence bone metabolism, and its specific transport system, the taurine transporter, is expressed in osteoblasts. The mean [Mg2+]i was 0.51+/-0.01 mM in normal culture media. Taurine caused an increase in [Mg(2+)]i by 0.72+/-0.04 mM in human osteoblast (HOB) cells. This increment in [Mg2+]i was inhibited significantly by PD98059, nifedipine, lidocaine, and imipramine. Taurine was also shown to stimulate the activation of ERK 1/2. This taurine-stimulated ERK 1/2 activation was inhibited by PD98059. In the present study, taurine was shown to increase cell proliferation and generate an increase in [Mg2+]i accompanied by ERK 1/2 activation in HOB cells.
Jeon SH, Lee MY, Kim SJ, Joe SG…
FEBS Lett. Dec 2007
Taurine transporter is expressed in osteoblasts.
Taurine influences bone metabolism and is taken up by cells via a specific transport system, the taurine transporter (TAUT). We report a link between taurine and bone homeostasis by demonstrating transcription and translation of TAUT in bone-forming cells. TAUT was expressed in human primary osteoblasts, the human osteosarcoma osteoblast-like cell line MG63, and the mouse osteoblastic cell line MC3T3-E1. Immunostaining with polyclonal antibodies also demonstrated the presence of TAUT in both human and murine osteoblasts. TAUT mRNA expression and [(3)H]taurine uptake increased during differentiation of MG63 cells in culture. Supplementation of culture medium with taurine enhanced alkaline phosphatase activity and osteocalcin secretion. The regulation and detailed function of taurine and TAUT in bone remain unclear, but our findings suggest a functional role for them in bone homeostasis.
Yuan LQ, Xie H, Luo XH, Wu XP…
Amino Acids Sep 2006
Effect of taurine feeding on bone mineral density and bone markers in rats.
The purpose of this study was to investigate the effect of dietary taurine supplementation on bone mineral density (BMD) and bone mineral content (BMC) in rats. Twenty Sprague-Dawley male rats (body weight 200 ± 10 g) were divided into two groups, control and taurine group (2% taurine-supplemented diet). All rats were fed on experimental diet and deionized water and libitum for 6 weeks. Serum alkaline phosphatase (ALP) activity, osteocalcin, PTH, and urinary deoxypyridinoline cross-links value were measured as markers of bone formation and resorption. BMD and BMC were measured using PIXImus (GE Lunar Co., Wisconsin) in spine and femur. The effect of diet on ALP, osteocalcine, and PTH was not significant. There were no significant differences in ALP, osteocalcine, and PTH concentration. Urinary calcium excretion was lower in taurine group than in control group. Femur BMC/weight of taurine group was significantly higher than control group. The results of this study showed the possible role of taurine in bone metabolism in male rats.
Choi MJ, Seo JN
Adv. Exp. Med. Biol. 2013
[Anti-osteopenic effect of taurine: possible involvement of activated MEK-ERK-Cbfa1 signaling].
Previously we first noted that taurine (TR) has anti-osteopenic effect on low Ca diet-induced osteopenia in rats (1). Employing osteoblastic MC3T3-E1 cells, the mechanism of the anti-osteopenic effect was explored in vitro. TR (1 mM) was found to promote mineralization of extracellular matrices, without affecting alkaline phosphataase activity. Gel shift assay using 32P-labeled OSE2 (osteoblast-specific cis-element 2: the consensus sequence for Cbfa1, refer to 2) indicated that TR (1 mM) increased the nuclear localization of Cbfa1, just as TPH (1-34) (3,4) and bisphosphonates did (5). In addition, TR was found to stimulate ERK phosphorylation. PD98059, a MEK inhibitor, suppressed effects of TR on both Cbfa1 transactivation and ERK activation. The results strongly suggest that TR first activates intracellular MEK-ERK-Cbfa1 signaling system thereby promoting mineralization and finally leading to its bone anabolic action.
Yasutomi C, Nakamuta H, Fujita T, Takenaga T…
Nippon Yakurigaku Zasshi Nov 2002
Taurine inhibits serum deprivation-induced osteoblast apoptosis via the taurine transporter/ERK signaling pathway.
Taurine has positive effects on bone metabolism. However, the effects of taurine on osteoblast apoptosis in vitro have not been reported. The aim of this study was to investigate the activity of taurine on apoptosis of mouse osteoblastic MC3T3-E1 cells. The data showed that 1, 5, 10, or 20 mM taurine resulted in 16.7, 34.2, 66.9, or 63.75% reduction of MC3T3-E1 cell apoptosis induced by the serum deprivation (serum-free α-MEM), respectively. Taurine (1, 5, or 10 mM) also reduced cytochrome c release and inhibited activation of caspase-3 and -9, which were measured using fluorogenic substrates for caspase-3/caspase-9, in serum-deprived MC3T3-E1 cells. Furthermore, taurine (10 mM) induced extracellular signal-regulated kinase (ERK) phosphorylation in MC3T3-E1 cells. Knockdown of the taurine transporter (TAUT) or treatment with the ERK-specific inhibitor PD98059 (10 μM) blocked the activation of ERK induced by taurine (10 mM) and abolished the anti-apoptotic effect of taurine (10 mM) in MC3T3-E1 cells. The present results demonstrate for the first time that taurine inhibits serum deprivation-induced osteoblast apoptosis via the TAUT/ERK signaling pathway.
Zhang LY, Zhou YY, Chen F, Wang B…
Braz. J. Med. Biol. Res. Jul 2011
PMID: 21710101 | Free Full Text
The effects of dietary taurine supplementation on bone mineral density in ovariectomized rats.
This study was performed to evaluate the effect of a diet rich in taurine (2.0 g/100 g) on bone metabolism in ovariectomized (OVX) rats. All rats were fed deionized water during the experimental period. Bone mineral density (BMD) and bone mineral content (BMC) of spine and femur were measured. Serum and urinary calcium and phosphorus content were determined. The levels serum osteocalcin and alkaline phosphatase (ALP) were used to assess bone formation. The rate of bone resorption was measured by the deoxypyridinoline (DPD) crosslink immunoassay and corrected for creatinine. Urinary Ca and P excretion, serum osteocalcin content, and the crosslink value were not significantly different between the Sham groups. The taurine supplemented, Sham group had higher spinal and femur BMC than those of the untreated control group, but the difference was not statistically significant. However, the taurine supplemented, Sham group had significantly higher spine and femur BMC per weight than those of the untreated control group. Within the OVX group, the taurine supplemented group had a lower crosslink value than the casein group. The taurine supplemented, OVX group had higher femur bone mineral content per weight than those of the control, OVX group, but the difference was not statistically significant. A study examining the long-term effect of taurine supplementation in humans is warranted.
Choi MJ, DiMarco NM
Adv. Exp. Med. Biol. 2009