Reports describing significant health risks due to inadequate vitamin D status continue to generate considerable interest amongst the medical and lay communities alike. Recent research on the various molecular activities of the vitamin D system, including the nuclear vitamin D receptor and other receptors for 1,25-dihydroxyvitamin D and vitamin D metabolism, provides evidence that the vitamin D system carries out biological activities across a wide range of tissues similar to other nuclear receptor hormones. This knowledge provides physiological plausibility of the various health benefits claimed to be provided by vitamin D and supports the proposals for conducting clinical trials. The vitamin D system plays critical roles in the maintenance of plasma calcium and phosphate and bone mineral homeostasis. Recent evidence confirms that plasma calcium homeostasis is the critical factor modulating vitamin D activity. Vitamin D activities in the skeleton include stimulation or inhibition of bone resorption and inhibition or stimulation of bone formation. The three major bone cell types, which are osteoblasts, osteocytes and osteoclasts, can all respond to vitamin D via the classical nuclear vitamin D receptor and metabolize 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D to activate the vitamin D receptor and modulate gene expression. Dietary calcium intake interacts with vitamin D metabolism at both the renal and bone tissue levels to direct either a catabolic action on the bone through the endocrine system when calcium intake is inadequate or an anabolic action through a bone autocrine or paracrine system when calcium intake is sufficient.
Calcium/metabolism ; Fractures, Bone/metabolism/pathology ; Humans ; Osteoporosis/metabolism/pathology ; Protein Binding ; Receptors, Calcitriol/genetics/metabolism ; Vitamin D/analogs & derivatives/*metabolism

Animals ; Bone and Bones ; cytology ; metabolism ; pathology ; Collagen ; metabolism ; Durapatite ; metabolism ; Female ; Osteoporosis ; metabolism ; pathology ; Ovariectomy ; adverse effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the relationship between the level of sex hormones and the loss of bone mass in aging male rats.

METHODSThirty male Sprague-Dawley rats were equally divided into five age groups and sacrificed at 35, 70, 160, 700 and 800 postnatal days (PD) , followed by measurement of the % Tb x Ar, Tb x Th, Tb x N and Tb x SP by bone histomorphometry and detection of the levels of serum testosterone (T) and estradiol (E2) by radioimmunoassay. The relationship between the changes of the T and E2 levels and those of bone histomorphometry was analyzed.

RESULTST and E2 levels were closely correlated with the bone mass in the aging male rats. The changes in T and E2 levels were simultaneous with those in the bone mass with the growth of the rats. T, E2, % Tb x Ar and Tb x N reached the peak in the 70 and 160 PD groups, and markedly decreased in the 700 PD group except Tb x Th and Tb x SP. The T levels in the 35, 70, 160, 700 and 800 PD groups were (118.53 +/- 18.35) ng/dl, (345.49 +/- 54.63) ng/dl, (368.83 +/- 60.03) ng/dl, (61.15 +/- 21.12) ng/dl and (60.35 +/- 19. 27) ng/dl, changing simultaneously with the E2 levels, which were (10.35 +/- 1.82) pg/ml, (16.92 +/- 3.13) pg/ml, (17.20 +/- 2.51) pg/ml, (5.87 +/- 2.34) pg/ml and (5.53 +/- 2.48) pg/ml, respectively. The metrological parameters of the bone structure in the five groups were as follows, Tb x Ar: (19.52 +/- 2.23)%, (26.28 +/- 2.18) %, (28.37 +/- 1.21) %, (15.62 +/- 1.68) % and (14.21 +/- 0.89) %; Tb x Th: (35.45 +/- 1.63) microm, (50.13 +/- 3.58) microm, (60.23 +/- 8.25) microm, (75.62 +/- 9.72) microm and (78.78 +/- 11.21) microm; Tb x N: (5.98 +/- 1.21) n/mm, (8.07 +/- 0.86) n/mm, (8.30 +/- 1.22) n/mm, (2.63 +/- 1.35) n/mm and (2.48 +/- 1.62) n/mm; Tb x SP: (126.34 +/- 18.15) microm, (136.26 +/- 15.27) microm, (261.08 +/- 76.43) microm, (323.12 +/- 78.12) microm and (330.23 +/- 50.20) microm.

CONCLUSIONChanges in the levels of sex hormones are closely correlated with those of bone mass. Both testosterone and estradiol are essential for bone development and bone mass maintenance.

Aging ; Animals ; Bone Density ; Bone Development ; Bone and Bones ; metabolism ; Cytoskeleton ; metabolism ; pathology ; Estradiol ; blood ; Male ; Osteoporosis ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood

The changes on the regional distributions and frequencies of two types of chromogranin, chromogranin A (CGA) and bovine Sp-1 chromogranin (BCG)-immunoreactive (IR)cells in gastrointestinal (GI)tract of osteoporotic Sprague-Dawley rat induced by ovariectomy were studied by immunohistochemical methods. The experimental animals were divided into two groups, one is non-ovariectomized group (Sham)and the other is ovariectomized group (OVX). Samples were collected from each part of GI tract at 10th week after ovariectomy or sham operation. CGA-IR cells were restricted to the stomach regions with various frequencies regardless of ovariectomy except for the fundus of OVX in which no cells were detected. In addition, BCG-IR cells were also restricted to the pylorus and duodenum regardless of ovariectomy. A significantly decrease of CGA IR cells was detected in OVX compared to that of Sham in both fundus and pylorus, and BCG-IR cells were also significantly decreased in the duodenum(p<0. 05). However, in the pylorus, BCG-IR cells in OVX showed similar frequency compared to that of Sham. In conclusion, the abnormality in density of chromogranin, a generally used GI endocrine cell marker, detected in this study may contribute to the development of GI symptoms in osteoporosis such as impairments of calcium and some lipids, frequently encountered in patients with postmenopausal osteoporosis.
Animals ; Chromogranin A ; Chromogranins/*metabolism ; Female ; Gastric Mucosa/*metabolism/pathology ; Gene Expression Regulation/physiology ; Humans ; Immunoglobulins/*metabolism ; Immunohistochemistry ; Intestinal Mucosa/*metabolism/pathology ; Models, Animal ; Osteoporosis, Postmenopausal/*metabolism/pathology ; Ovariectomy ; Rats ; Rats, Sprague-Dawley

Previous case-control studies have shown various degrees of inverse correlation between osteoarthritis (OA) and osteoporosis (OP). The aim of this study was to examine the relationship between osteophytes at the cervical , lumbar vertebrae and knee, and the bone mineral density (BMD) of lumbar spine. We analyzed the data on 4091 female patients (aged 13 to 92 years). Osteophyte was defined by X ray examination. BMD of the lumbar spine (LS) was measured by dual energy X-ray absorptiometry (Lunar DPX). The association of osteophytes with BMD and osteophytes at different sites and different degrees were assessed by covariance analysis. Adjustments were made for age and body mass index. The relationship between osteophytes and BMD was analyzed by Binary Logistic Regression. BMD at each site was greater in the female with osteophytes (L4 BMD: P < 0.01, Mean BMD: P < 0.05); the relationship between osteophytes and osteoporosis and that between duration of osteophytes and osteoporosis were inversely correlated (P < 0.01). It confirms the existence of an inverse relationship between osteophytes and OP while a positive relationship is between age, body mass index and osteoporosis.
Absorptiometry, Photon ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Bone Density ; Female ; Humans ; Lumbar Vertebrae ; metabolism ; pathology ; Middle Aged ; Osteophyte ; metabolism ; Osteoporosis ; metabolism ; Young Adult

BACKGROUNDOsteoporosis is a common complication of chronic obstructive pulmonary disease (COPD). Recent clinical and biological researches have increasingly delineated the biomolecular pathways of bone metabolism regulation in COPD. We extended this work by examining the specific association and potential contribution of the osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL) axis to the pathogenesis of osteoporosis in advanced COPD. The aim of this study was to assess the relationships of serum OPG, RANKL, and tumor necrosis factor-alpha (TNF-μ) with bone turnover in men with very severe COPD.

METHODSPulmonary function, T-score at the lumbar spine (LS) and femoral neck (FN), serum OPG, RANKL, soluble receptor of tumor necrosis factor-alpha-I and II (sTNFR-I, sTNFR-II), osteocalcin (OC), and β-CrossLaps (βCL) levels were measured in 45 men with very severe stage COPD and 36 male non-COPD volunteers. COPD patients and healthy controls were compared using an independent t-test and Mann-Whitney U-test. The Pearson coefficient was used to assess the relationships between variables.

RESULTSOPG and OC were lower in male COPD patients than in control subjects whereas RANKL, serum βCL, TNF-μ, and its receptors were higher. OPG directly correlated with forced expiratory volume in 1 s (FEV1) % predicted (r = 0.46, P < 0.005), OC (r = 0.34, P < 0.05), LS (r = 0.56, P < 0.001), and FN T-score (r = 0.47, P < 0.01). In contrast, serum RANKL inversely associated with LS and FN T-score (r = -0.62, P < 0.001 and r = -0.48, P < 0.001) but directly correlated with βCL (r = 0.48, P < 0.001). In addition, OPG was inversely correlated with RANKL (r = -0.39, P < 0.01), TNF-μ (r = -0.56, P < 0.001), and sTNFR-I (r = -0.40, P < 0.01).

CONCLUSIONOur results suggest that serum OPG and RANKL levels are inversely associated with bone loss in men with advanced stage COPD.

Bone Density ; physiology ; Cross-Sectional Studies ; Humans ; Male ; Middle Aged ; Osteoporosis ; metabolism ; pathology ; Osteoprotegerin ; metabolism ; Pulmonary Disease, Chronic Obstructive ; metabolism ; pathology ; RANK Ligand ; metabolism ; Respiratory Function Tests ; Tumor Necrosis Factor-alpha ; metabolism

The purpose of this paper is to investigate that the effect of cyclic biaxial mechanical strain on proliferation and synthetic function in the osteoblasts isolated from 3 month-old normal female Sprague-Dawley (SD) rats and osteoporotic rats. The osteoblasts were cultured in F-12 medium contained with 10% fetal bovine serum (FBC) and grown to subconfluency in Flexercell apparatus in a humidified incubator with 5% CO2 and 95% air at 37 degrees C. Mechanical strain was applied to the cells for periods of 30 min, 2, 4 and 8 hours every day,lasting 2 days. The amplitude of mechanical strain applied to the cells were 400, 1000 and 4000 microm strain respectively, at a frequency of one hertz (1 H). Unstrained cells were used as control. The results showed that proliferation activity of osteoblast in osteoporotic rats are higher than that in normal rats without mechanical strain the mechanical strain can elevate the proliferation activity and the synthetic function of osteoblast from normal rats at 400, 1000 microm strain. However, the mechanical strain increased significantly the proliferation in the osteoblasts and suppressed obviously the synthetic function in the osteoblasts at 4000 microm strain. The mechanical strain don't affect the proliferation activity and the synthetic function of osteoblast from osteoporotic rats at 400 microm strain. The mechanical strain decrease the proliferation activity of osteoblast from osteoporotic rats at 1000 microm strain. The mechanical strain can elevate the proliferation activity and the synthetic function of osteoblast from osteoporotic rats at 4000 microm strain. In our study, the reaction of the osteoblasts from normal rats and osteoporotic rats to the mechanical stimulation suggested that there are more highly sensitive to the mechanical stimulation in the osteoblasts from normal rats than that from osteoporotic rats.
Animals ; Apoptosis ; Cell Division ; Cell Separation ; Cells, Cultured ; Female ; Osteoblasts ; metabolism ; pathology ; Osteocalcin ; biosynthesis ; Osteoporosis ; pathology ; Rats ; Rats, Sprague-Dawley ; Stress, Mechanical

OBJECTIVETo observe the bone mineral density changes of coal workers' pneumoconiosis.

METHODSWe chose 150 cases of One-Triple coal workers pneumoconiosis in Jincheng Coal Mining Group, all of workers were male, of 55-years old-80 years old, an average of 67 years old. 10 years of age to grouping, Whole body bone mineral density and T value were measured by body dual-energy X-ray absorptiometry. We analyzed the BMD changes bone loss, osteoporosis occurrence.

RESULTSThe BMD of six parts were not declined obviously in One stage of coal workers' pneumoconiosis; the BMD of Chest bone, pelvis and spine were declined obviously in two stage of coal workers' pneumoconiosis; the BMD of six parts were declined obviously in Triple stage of coal workers' pneumoconiosis; The occurrence rate of bone loss was significantly higher in Two and Triple coal workers pneumoconiosis. The occurrence rate of osteoporosis was significantly higher in Triple coal workers pneumoconiosis.

CONCLUSIONWith the increase in the severity of coal workers' pneumoconiosis, the BMD of six parts were declined, The occurrence rate of bone loss osteoporosis was significantly higher.

Aged ; Aged, 80 and over ; Anthracosis ; epidemiology ; metabolism ; pathology ; Bone Density ; Case-Control Studies ; Coal Mining ; Humans ; Male ; Middle Aged ; Osteoporosis ; epidemiology ; pathology

OBJECTIVETo observe the effect of Gusongbao (GSB) on proliferation and metabolism of osteoblast cultured in vitro.

METHODSOld rats, aged 18 months, were given GSB 1.5 g/kg, twice a day for 3 days by intragastric perfusion. Blood of the rats was collected 1 hr after the final perfusion to isolate serum for preparing, with D8900 medium, the culture media containing 7.5% or 15% GSB, which was used to culture osteoblast for 24 hrs. Besides, D8900 media containing 7.5% or 15% old rats'serum without medication, containing 20 mumol/L, sodium fluoride, and simple D8900 medium were prepared for control. The cell proliferation was detected by MTT method, and the changes of Ca2+ concentration and ALP content in supernatant of culture were also observed.

RESULTSThe osteoblast proliferation cultured in GSB serum containing medium was significantly increased than those cultured in the other control media (P < 0.01), at the same time, the Ca2+ consumption increased and the ALP content elevated significantly (P < 0.05, P < 0.01).

CONCLUSIONGSB could promote the DNA synthesis, increase the utilization of Ca2+ and accelerate the growth and proliferation of osteoblast.

Animals ; Calcium ; metabolism ; Cell Division ; drug effects ; Cells, Cultured ; DNA ; biosynthesis ; Drugs, Chinese Herbal ; pharmacology ; Female ; Male ; Osteoblasts ; cytology ; metabolism ; Osteoporosis ; pathology ; Rabbits ; Rats ; Rats, Wistar

The purpose of this study was to determine whether esterification of dehydroepiandrosterone with aspartate (DHEA-aspartate) could reduce peroxisomal proliferation induced by DHEA itself, without loss of antiosteoporotic activity. Female Sprague-Dawley rats were ovariectomized, then DHEA or DHEA-aspartate was administered intraperitoneally at 0.34 mmol/kg BW 3 times a week for 8 weeks. DHEA-aspartate treatment in ovariectomized rats significantly increased trabeculae area in tibia as much as DHEA treatment. Urinary Ca excretion was not significantly increased by DHEA or DHEA-aspartate treatment in ovariectomized rats, while it was significantly increased by ovariectomy. Osteocalcin concentration and alkaline phosphatase activity in serum and cross linked N-telopeptide type I collagen level in urine were not significantly different between DHEA-aspartate and DHEA treated groups. DHEA-aspartate treatment significantly reduced liver weight and hepatic palmitoyl-coA oxidase activity compared to DHEA treatment. DHEA-aspartate treatment maintained a nearly normal morphology of peroxisomes, while DHEA treatment increased the number and size of peroxisomes in the liver. According to these results, it is concluded that DHEA-aspartate ester has an inhibitory effect on bone loss in ovariectomized rats with a marked reduction of hepatomegaly and peroxisomal proliferation compared to DHEA.
Adjuvants, Immunologic/pharmacology* ; Adjuvants, Immunologic/metabolism ; Adjuvants, Immunologic/chemistry ; Animal ; Aspartic Acid/pharmacology* ; Aspartic Acid/metabolism ; Aspartic Acid/chemistry ; Biological Markers ; Calcium/urine ; Calcium/blood ; Disease Models, Animal ; Esterification ; Fatty Acid Desaturases/metabolism ; Female ; Injections, Intraperitoneal ; Lipoproteins, HDL Cholesterol/blood ; Lipoproteins, LDL Cholesterol/blood ; Liver/enzymology ; Liver/drug effects ; Organ Weight ; Osteoporosis/pathology ; Osteoporosis/metabolism* ; Osteoporosis/drug therapy* ; Ovariectomy* ; Peroxisomes/metabolism* ; Prasterone/pharmacology* ; Prasterone/metabolism ; Prasterone/chemistry ; Rats ; Rats, Sprague-Dawley ; Tibia/pathology ; Tibia/metabolism ; Triglycerides/blood