Tag Archives: abstract

Zinc-Carnosine Prevents Effects of Aluminium on Bone in Rats

Abstract

Beta-alanyl-L-histidinato zinc prevents the toxic effect of aluminium on bone metabolism in weanling rats.

The preventive effect of beta-alanyl-L-histidinato zinc (AHZ) on the toxic action of aluminium on bone metabolism was investigated in the femoral diaphysis of weanling rats. Aluminium chloride (5.0, 10.0 and 20.0 mumol A1/100 g body weight) was orally administered for 3 days. The dose of 10.0 and 20.0 mumol A1/100 g caused a significant increase in serum calcium concentration and bone acid phosphatase activity, while bone alkaline phosphatase activity and calcium content were not altered significantly. Moreover, the bone DNA content was significantly decreased by the doses of 10.0 and 20.0 mumol A1/100 g. Meanwhile, the increase in serum calcium concentration caused by the administration of aluminium (20 mumol/100 g) was completely prevented by the simultaneous administration of AHZ (1.0 and 2.5 mg/100 g) for 3 days, although AHZ alone did not have any effect. Also, the effects of aluminium (20.0 mumol/100 g) to increase bone acid phosphatase activity and to decrease the bone DNA content were completely blocked by the simultaneous administration of AHZ (1.0 and 2.5 mg/100 g). AHZ (1.0 and 2.5 mg/100 g) alone had the effect to increase bone DNA content but not bone acid phosphatase activity. The present study indicates that AHZ can prevent the revelation of the toxic effect of aluminium on bone metabolism in rats.

Yamaguchi M, Ozaki K
Pharmacology 1990
PMID: 2096394

Zinc-Carnosine Stimulates Bone In Vitro

Abstract

Stimulatory effect of beta-alanyl-L-histidinato zinc on bone formation in tissue culture.

The present investigation was undertaken to clarify the in vitro effect of beta-alanyl-L-histidinato zinc (AHZ) on bone metabolism in tissue culture. Calvaria were removed from weanling rats (3-week-old male) and cultured for periods up to 96 h in Dulbecco’s modified Eagle medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained 10(-8) to 10(-4) mol/l AHZ. The bone cellular zinc content was significantly increased in cultures with concentrations of AHZ greater than 10(-6) mol/l. With 10(-5) mol/l zinc sulfate, the bone cellular zinc content was significantly elevated. Bone calcium content was significantly increased by the presence of 10(-7) to 10(-4) mol/l AHZ. This increase was blocked by the presence of 10(-7) mol/l cycloheximide. Bone alkaline phosphatase activity was elevated in the presence of AHZ (10(-7) to 10(-4) mol/l), whereas it did not significantly alter acid phosphatase activity Bone collagen and DNA contents were significantly increased by 10(-7) to 10(-5) mol/l AHZ, while they were not significantly elevated by zinc sulfate (10(-7) and 10(-6) mol/l). The AHZ (10(-5) mol/l)-induced increase in bone alkaline phosphatase activity and DNA content were prevented by 10(-4) mol/l dipicolinate, a chelator of zinc. Furthermore, the AHZ (10(-5) mol/l)-induced increase in bone alkaline phosphatase activity, collagen and DNA contents were blocked by 10(-7) mol/l cycloheximide. These findings indicate that AHZ had a direct stimulatory effect on bone mineralization in vitro, and that bone protein synthesis was a necessary component of this response. The AHZ effect was more intensive than that of zinc sulfate.

Yamaguchi M, Miwa H
Pharmacology 1991
PMID: 1852783

Zinc-Carnosine Inhibits Bone Resorption In Viro

Abstract

Inhibitory effect of beta-alanyl-L-histidinato zinc on bone resorption in tissue culture.

The inhibitory effect of beta-alanyl-L-histidinato zinc (AHZ) on bone resorption in tissue culture was investigated. Calvaria were removed from weanling rats (3-week-old male) and cultured for periods up to 48 h in Dulbecco’s modified Eagle medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained 10(-7) to 10(-4) mol/l AHZ. The bone-resorbing factors, parathyroid hormone (1-34) (PTH; 10(-7) mol/l), prostaglandin E2 (10(-5) mol/l), interleukin-1 alpha (IL1 alpha; 50 U/ml), and lipopolysaccharide (10 micrograms/ml), caused a significant decrease in bone calcium content. The decreases in bone calcium content induced by bone-resorbing factors were completely inhibited by the coexistence of AHZ (10(-6) to 10(-4) mol/l). Also, AHZ (10(-5) mol/l) completely inhibited the PTH (10(-7) mol/l) or IL1 alpha (50 U/ml)-induced increase in medium glucose consumption and lactic acid production by bone tissue. Furthermore, AHZ (10(-5) mol/l) fairly blocked both PTH (10(-7) mol/l)-increased acid phosphatase and decreased alkaline phosphatase activities of bone tissue. The inhibitory effect of AHZ (10(-5) mol/l) on PTH (10(-7) mol/l)-stimulated bone resorption was clearly prevented by the presence of 10(-4) mol/l dipicolinate, a chelator of zinc. However, zinc sulfate (10(-7) to 10(-4) mol/l) did not inhibit the PTH (10(-7) mol/l)-stimulated bone resorption in tissue culture. These findings indicate that AHZ had a direct inhibitory effect on bone resorption in vitro, and the AHZ effect was found in the chemical form of zinc-chelated dipeptide.

Yamaguchi M, Segawa Y, Shimokawa N, Tsuzuike N…
Pharmacology 1992
PMID: 1465476

Zinc-Carnosine Prevents Hydrocortisone Effects on Bones in Rats

Abstract

beta-Alanyl-L-histidinato zinc prevents hydrocortisone-induced disorder of bone metabolism in rats.

The preventive effect of beta-alanyl-L-histidinato zinc (AHZ) on osteopenia was investigated in rats treated with hydrocortisone. Rats received hydrocortisone (75 mg/kg body weight per day) s.c. for 30 days. The steroid treatment caused a significant increase in serum alkaline phosphatase activity and parathyroid hormone (PTH-c) level, while serum calcium, inorganic phosphorus, and zinc concentrations were not significantly altered. The femoral-diaphyseal alkaline phosphatase activity, deoxyribonucleic acid (DNA), and calcium contents were significantly decreased by the treatment of steroid, although the bone zinc content was not appreciably altered. When AHZ (10, 30, and 100 mg/kg per day) was administered p.o. for 30 days to rats giving the steroid, the dose of AHZ (30 and 100 mg/kg) completely prevented the increases in serum alkaline phosphatase activity and PTH-c level and the decreases in femoral-diaphyseal alkaline phosphatase activity, DNA, and calcium contents caused by the steroid treatment. The dose of AHZ (10, 30, and 100 mg/kg) significantly increased zinc content in the femoral diaphysis. Present results indicate that the dose of AHZ can prevent the disorder of bone metabolism caused by hydrocortisone treatment. AHZ may have a therapeutic role in the steroid-induced osteopenia.

Segawa Y, Tsuzuike N, Itokazu Y, Tagashira E…
Res Exp Med (Berl) 1992
PMID: 1439196

Zinc-Carnosine Stimulates Bone Formation in Rats

Abstract

Effect of the new zinc compound beta-alanyl-L-histidinato zinc on bone metabolism in elderly rats.

The effect of a new zinc compound beta-alanyl-L-histidinato zinc (AHZ) on bone metabolism was investigated in aged rats (30 weeks old). AHZ (1.0, 2.5 and 7.5 mg/100 g body weight) was orally administered to rats 3 times at 24-hour intervals, and the rats were bled 24 h after the last administration. The administration of AHZ (7.5 mg/100 g) did not cause an appreciable alteration of calcium and inorganic phosphorus concentrations in the serum, and zinc, calcium and deoxyribonucleic acid contents in the femoral diaphysis were significantly increased by the administration of AHZ (7.5 mg/100 g). The bone alkaline phosphatase activity was significantly increased by doses of 1.0-7.5 mg AHZ/100 g. These results suggest that AHZ has a stimulatory effect on bone formation and calcification in aged rats.

Yamaguchi M, Ozaki K
Pharmacology 1990
PMID: 2096395

Low Zinc Causes Undesirable Changes in Bone Markers; Higher Zinc May Increase Magnesium Requirement in Postmenopausal Women

Abstract

A moderately high intake compared to a low intake of zinc depresses magnesium balance and alters indices of bone turnover in postmenopausal women.

To determine whether moderately high or low intakes of zinc adversely affect the copper status of postmenopausal women to result in unfavorable changes in calcium and magnesium metabolism and other indicators of bone turnover.
After a 10-day equilibration period in which the diet provided 31.5 micromol (2 mg) Cu and 137.7 micromol (9 mg) Zn/8.4 MJ (2000 kcal), the subjects were randomly divided into two groups, with one group fed the basal diet supplemented to provide 15.7 micromol (1 mg) Cu/8.4 MJ, and the other group fed the same diet supplemented to provide 47.2 micromol (3 mg) Cu/8.4 MJ. After equilibration, both groups were fed the basal diet with no zinc supplemented (provided 45.9 micromol [3 mg] Zn/8.4 MJ) for 90 days; this was followed by another 10-day equilibration period before the basal diet was supplemented with zinc to provide 811 micromol (53 mg)/8.4 MJ for 90 days.
The metabolic unit of the Grand Forks Human Nutrition Research Center, Grand Forks, ND, USA.
A total of 28 postmenopausal women recruited by advertisement throughout the United States of America. Among them, 25 women (64.9+6.7 y) completed the study; 21 as designed.
The moderately high intake compared to the low intake of zinc increased the excretion of magnesium in the feces and urine, which resulted in a decreased magnesium balance. In the women fed low dietary copper, plasma osteocalcin was higher during the low-zinc than high-zinc dietary period. The urinary excretion of N-telopeptides was increased and the serum calcitonin concentration was decreased by high dietary zinc regardless of dietary copper.
A moderately high intake of zinc (811 micromol/day; 53 mg/day) did not induce changes in copper metabolism that resulted in unfavorable changes in bone or mineral metabolism. However, low dietary zinc (45.9 micromol/day; 3 mg/day) apparently resulted in undesirable changes in circulating calcitonin and osteocalcin. As a moderately high intake of zinc decreased magnesium balance, further study of the possibility that a high intake of zinc is a health concern for individuals consuming less than the recommended amounts of magnesium is warranted.

Nielsen FH, Milne DB
Eur J Clin Nutr May 2004
PMID: 15116072

Zinc Increases IGF-1 Activity in Mouse Osteoblasts In Vitro

Abstract

Role of zinc in regulation of protein tyrosine phosphatase activity in osteoblastic MC3T3-E1 cells: zinc modulation of insulin-like growth factor-I’s effect.

Zinc, an essential trace element, has been demonstrated to stimulate bone growth in animal and human. The cellular mechanism by which zinc stimulates bone growth has not been fully clarified. The effect of hormone and zinc on protein tyrosine phosphatase activity in osteoblastic MC3T3-E1 cells was investigated. Cells were cultured for 72 h in medium containing 10% fetal bovine serum (FBS) to obtain subconfluent monolayers, and then exchanged to culture medium containing either vehicle, zinc sulfate or various hormones in the absence of 10% FBS. After medium change, cells were cultured for 48 h. Protein tyrosine phosphatase activity in the lysate of cells was significantly increased by culture with zinc (10(-6) – 10(-4) M). The effect of zinc in increasing the enzyme activity was completely blocked by culture with cycloheximide (10(-7 )M), an inhibitor of protein synthesis, or 5, 6-dichloro-l-beta-D- riboifuranosylbenzimidarzole (DRB) (10(-6) M), an inhibitor of translational activity. Addition of calcium chloride (10 microM) into the reaction mixture caused a significant increase in protein tyrosine phosphatase activity; this increase was completely blocked in the presence of trifluoperazine (50 microM), an antagonist of calmodulin. Culture with zinc caused a significant increase in Ca2+/calmodulin-dependent protein tyrosine phosphatase activity in osteoblastic cells. Protein tyrosine phosphatase activity was significantly raised by culture with parathyroid hormone (human PTH [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33]; 10(-7) M), 17beta-estradiol (10(-7) M), insulin-like growth factor-I (IGF-I; 10(-8) M) or insulin (10(-8) M). The enzyme activity was not significantly enhanced by the addition of calcium (10 microM) into the reaction mixture. The effect of PTH or IGF-I in increasing protein tyrosine phosphatase activity was completely blocked by culture with DRB. The IGF-I-induced increase in enzyme activity was significantly enhanced by culture with zinc. Such an effect was not seen in the case of PTH. Moreover, the effect of IGF-I in increasing proliferation of osteoblastic cells was significantly enhanced by culture with zinc. The effect of PTH was not enhanced by zinc. This study demonstrates that protein tyrosine phosphatase activity in osteoblastic cells is enhanced by various bone anabolic factors, and that zinc modulates the effect of IGF-I on protein tyrosine phosphatase activity and cell proliferation.

Yamaguchi M, Fukagawa M
Calcif. Tissue Int. Jan 2005
PMID: 15477998

Zinc Intake and Plasma Level Associated with Bone Density in Men with Osteoporosis

Abstract

Zinc intakes and plasma concentrations in men with osteoporosis: the Rancho Bernardo Study.

Low zinc intakes and reduced blood zinc concentrations have been reported to be associated with osteoporosis in women.
The objective was to examine the independent association between dietary zinc and plasma zinc and the association of each with bone mineral density (BMD) and 4-y bone loss in community-dwelling older men.
Of the original Rancho Bernardo Study subjects, 396 men (age: 45-92 y) completed BMD measurements at baseline in 1988-1992 and 4 y later. Osteoporosis was defined as a BMD > or = 2.5 SDs below the mean for young women (a T-score < or = -2.5). At baseline, dietary intake data were collected by using a standard food-frequency questionnaire, and plasma zinc concentrations were measured by using inductively coupled plasma spectroscopy.
The mean dietary zinc intake was 11.2 mg, and the mean plasma zinc concentration was 12.7 micromol/L. Plasma zinc was correlated with total zinc intake (diet plus supplements). Dietary zinc intake and plasma zinc concentrations were lower in men with osteoporosis at the hip and spine than in men without osteoporosis at those locations. BMDs for the hip, spine, and distal wrist were significantly lower in men in the lowest plasma zinc quartile (<11.3 micromol/L) than in men with higher plasma zinc concentrations. The association between plasma zinc and BMD was cross-sectional, longitudinal, and independent of age or body mass index. However, plasma zinc did not predict bone loss during the 4-y interval.
Dietary zinc intake and plasma zinc each have a positive association with BMD in men.

Hyun TH, Barrett-Connor E, Milne DB
Am. J. Clin. Nutr. Sep 2004
PMID: 15321813 | Free Full Text

Zinc Deficiency or Calorie Restriction Impares Bone Development in Weanling Rats

Abstract

Zinc-deficient rats have more limited bone recovery during repletion than diet-restricted rats.

The objective of this study was to investigate the effects of dietary zinc deficiency and diet restriction on bone development in growing rats, and to determine whether any adverse effects could be reversed by dietary repletion. Weanling rats were fed either a zinc-deficient diet ad libitum (ZD; <1 mg zinc/kg) or nutritionally complete diet (30 mg zinc/kg) either ad libitum (CTL) or pair-fed to the intake of the ZD group (DR; diet-restricted) for 3 weeks (deficiency phase) and then all groups were fed the zinc-adequate diet ad libitum for 3, 7, or 23 days (repletion phase). Excised femurs were analyzed for bone mineral density (BMD) using dual-energy x-ray absorptiometry, and plasma was analyzed for markers of bone formation (osteocalcin) and resorption (Ratlaps). After the deficiency phase, ZD had lower body weight and reduced femur BMD, zinc, and phosphorus concentrations compared with DR; and these parameters were lower in DR compared with CTL. Femur calcium concentrations were unchanged among the groups. Reduced plasma osteocalcin in ZD and elevated plasma Ratlaps in DR suggested that zinc deficiency limits bone formation while diet restriction accelerates bone resorption activity. After 23 days of repletion, femur size, BMD, and zinc concentrations remained lower in ZD compared with DR and CTL. Body weight and femur phosphorus concentrations remained lower in both ZD and DR compared with CTL after repletion. There were no differences in plasma osteocalcin concentrations after the repletion phase, but the plasma Ratlaps concentrations remained elevated in DR compared with CTL. In summary, both ZD and DR lead to osteopenia during rapid growth, but the mechanisms appear to be due to reduced modeling in ZD and higher turnover in DR. Zinc deficiency was associated with a greater impairment in bone development than diet restriction, and both deficiencies limited bone recovery during repletion in growing rats.

Hosea HJ, Taylor CG, Wood T, Mollard R…
Exp. Biol. Med. (Maywood) Apr 2004
PMID: 15044713

Zinc, but not Zinc-Carnosine, Enhances Anabolic Effect of IGF-1 in Mouse Osteoblasts In Vitro

Abstract

Zinc modulation of insulin-like growth factor’s effect in osteoblastic MC3T3-E1 cells.

Whether the anabolic effect of insulin-like growth factor-I (IGF-I) in osteoblastic MC3T3-E1 cells is modulated by zinc, an activator of bone formation, was investigated in vitro. After subculture for 3 days, the cells were cultured for 72 h with IGF-I (10(-8) M). The peptide produced a significant increase of protein concentration, deoxyribonucleic acid (DNA) content, and cell number in the cells. These increases were markedly enhanced by the presence of zinc sulfate (10(-5) M), but not zinc-chelating dipeptide (beta-alanyl-L-histidinato zinc; 10(-5) M). Also, the cellular alkaline phosphatase activity was synergistically increased by the presence of both IGF-I and zinc sulfate. Thus, effect was not seen in the presence of both insulin (10(-8) M) and zinc sulfate (10(-5) M). The effect of zinc sulfate to enhance the IGF-I-increased alkaline phosphatase activity and protein concentration in the cells was clearly prevented by the presence of cycloheximide (10(-6) M), staurosporin (10(-8) M), or okadaic acid (10(-7) M) with an effective concentration. However, staurosporin had a partial inhibiting effect on the IGF-I or the IGF-I plus zinc-induced increases in cellular protein, although okadaic acid entirely blocked the IGF-I or the IGF-I plus zinc effect. The present study demonstrates that the anabolic effect of IGF-I in osteoblastic cells is enhanced by zinc ion. The enhancement by zinc may be mediated through the signaling pathway of protein kinase C and protein phosphatase in the cells.

Matsui T, Yamaguchi M
Peptides 1995
PMID: 8532589