Decrease In Bone Mineral Content Research Articles

Sex-specific relationships between insulin resistance and bone mineral content in Korean adolescents

The aim of this study was to examine sex-specific relationships between insulin resistance (IR) and bone mineral content (BMC) according to age group and weight status. A population-based sample of 618 Korean adolescents (315 male and 303 female), aged 10-19years from the Fourth Korea National Health and Nutrition Examination Survey, 2009. They were divided into three age groups (10-12; 13-16; 17-19years) and two weight groups (non-overweight vs. overweight). IR was assessed using the homeostatic model of assessment of IR (HOMA-IR). Soft tissue composition (fat and lean mass) and BMC of the whole body, proximal femur, and lumbar spine were measured by dual energy X-ray absorptiometry. Adiposity (body mass index, waist circumference, or soft tissue composition), age, height, total cholesterol, triglycerides, high density lipoprotein cholesterol, alkaline phosphatase, serum vitamin D, dietary calcium and energy intake, and menarche for females were adjusted using general linear models of a complex sampling design. Higher HOMA-IR was associated with a decrease in BMC in male adolescents aged 13-19years after adjustment for adiposity and other confounders, while the associations were not significant in male adolescents aged 10-12years and female adolescents. After adjustment for adiposity and confounders, the inverse associations between HOMA-IR and BMC were more consistent in non-overweight male adolescents than in other weight groups (overweight males and non-overweight and overweight females). The unfavorable effect of IR on BMC appears to be more obvious in males aged 13-19years or non-overweight males than in females.

Low-calcium dialysate as a risk factor for decline in bone mineral density in peritoneal dialysis patients

Few studies have linked changes in bone mineral density (BMD) in peritoneal dialysis (PD) patients to the calcium concentration in peritoneal dialysate. In total, 236 incident patients who underwent an annual BMD determination for 2 years were enrolled. The patients were divided into two groups: the standard calcium dialysate (SCD) group (n = 190; 1.75 mmol/l) and the low-calcium dialysate (LCD) group (n = 46; 1.25 mmol/l). There were no significant differences between the baseline demographics of the two groups, such as age, diabetes, calcium, phosphorus, alkaline phosphatase (ALP), intact parathyroid hormone (i-PTH) levels or variables related to BMD. Univariate and multivariate analyses [adjusted for age, gender and time-averaged 25(OH)-vitamin D] determined that the LCD group had higher time-averaged i-PTH and ALP and a greater decrease in bone mineral content, lumbar spine BMD, subtotal BMD and total BMD compared to the SCD group. LCD is associated with a more rapid decline in BMD, higher i-PTH and higher ALP in PD patients. It is suggested that LCD be avoided for PD patients at risk of osteoporosis and hyperparathyroidism.

Deflazacort in comparison to other steroids for nephrotic syndrome

Patients with nephrotic syndrome require steroids for long time and sometimes repeatedly resulting in various adverse effects. Deflazacort (DFZ) had been described as equally effective and with fewer side effects as compared with other steroids. This review evaluates the literature on efficacy and toxicity of DFZ as compared with other therapies for nephrotic syndrome. A systematic review of Pubmed database and Cochrane Central Register of Controlled Trials with last search date of 20th April 2011. Search terms included “nephrotic AND deflazacort” without any limitations. Randomized control trials comparing DFZ vs placebo or other therapies in subjects with nephrotic syndrome were included. Two authors extracted data independently. Three studies meet inclusion criteria and data were synthesized qualitatively. The limited evidence suggested that DFZ appeared to be equally effective in inducing remission or decreasing proteinuria in patients with nephrotic syndrome. It caused significantly less decrease in bone mineral content (BMC) in spine as compared with prednisolone. The results related to weight change, blood pressure change, Cushingoid symptoms, and urinary calcium excretion were inconsistent between included studies. By reviewing the available limited evidence, DFZ appears to be of similar efficacy for nephrotic patients, but there were inconsistent results regarding side effect profile of DFZ as compared with other steroids except for decrease in BMC where DFZ was better. There is need for larger randomized controlled trials to evaluate effectiveness and adverse effect profile of DFZ as compared with other steroids in nephrotic syndrome.

Decreases in Bone Mineral Content by Dietary All-Trans Retinoic Acid Precede Decreases in Bone Mineral Density in a Weanling Rat Model of Cigarette Smoke - Induced Lung Injuries

Research has indicated that excessive vitamin A can have deleterious impacts on bone. Retinoic acid (RA), the most active metabolite of vitamin A, has been tested in clinical trials for treatment of lung cancer and emphysema. These trials are not measuring Bone Mineral Content (BMC) or Bone Mineral Density (BMD). In this study, we used an animal model to determine potential deleterious effects of all-trans RA on bone mass when used as a means to protect against or treat cigarette smoke-induced lung injuries, and also to evaluate BMC as a potential early indicator of osteoporosis risk. Twenty-four male weanling rats were fed either a control diet or a RA-supplemented diet. Half of each group was exposed to 40 cigarettes per day, 5 days per week, for 4 weeks. BMC and BMD were measured at weeks 2 and 4. RA supplementation in all groups significantly decreased (p < 0.05) only BMC at week 2 and both BMC and BMD (both p < 0.05) at week 4. The same results were observed when BMC was expressed relative to body weight. These data suggest that caution should be used when RA is used to treat smoke-related lung injuries.

Bone Loss in Adolescents After Bariatric Surgery

To evaluate bone loss in adolescents after Roux-en-Y gastric bypass surgery and to determine the extent to which bone loss was related to weight loss. We hypothesized that adolescents would lose bone mass after surgery and that it would be associated with weight loss. We conducted a retrospective case review of 61 adolescents after bariatric surgery. Whole-body bone mineral content (BMC) and density (BMD) were measured by dual-energy radiograph absorptiometry, and age- and gender-specific BMD z scores were calculated. Measurements were obtained when possible before surgery and then every 3 to months after surgery for up to 2 years. Data were analyzed by using a mixed-models approach, and regression models were adjusted for age, gender, and height. Whole-body BMC, BMD z score, and weight decreased significantly over time after surgery (P < .0001 for all). In the first 2 years after surgery, predicted values on the basis of regression modeling for BMC decreased by 7.4%, and BMD z score decreased from 1.5 to 0.1. During the first 12 months after surgery, change in weight was correlated with change in BMC (r = 0.31; P = .02). Weight loss accounted for 14% of the decrease in BMC in the first year after surgery. Bariatric surgery is associated with significant bone loss in adolescents. Although the predicted bone density was appropriate for age 2 years after surgery, longer follow-up is warranted to determine whether bone mass continues to change or stabilizes.

Accelerated bone loss, but not low periosteal expansion, is associated with higher all-cause mortality in older men – prospective MINOS study

Background Low bone mineral density (BMD), high bone resorption, fragility fractures and, possibly, accelerated bone loss are associated with higher mortality. However, it is not known if the higher mortality is related to lower volumetric BMD or lower bone width, to faster bone loss on endosteal surfaces (inside bone) or to slower periosteal apposition (formation of bone on the outer bone surface). Methods We assessed the association of 10-year mortality with bone width and bone loss in 782 men aged 50–85 years. Results Low bone width and slow periosteal apposition at the femoral neck, distal radius and distal ulna were not associated with higher mortality. Accelerated apparent bone loss (decrease in BMD), net bone loss (decrease in bone mineral content) and estimated endosteal bone loss were associated with a higher 10-year all-cause mortality after adjustment for age and other confounders. Accelerated apparent bone loss at the total hip (lowest quartile) was associated with a two-fold higher mortality (Hazard Ratio (HR)=1.96, 95% Confidence interval (CI): 1.33, 2.89, p<0.001). Conclusion Lack of association between bone size and mortality shows that periosteal expansion is not an artifact induced by the selective mortality of men with narrow bones. We confirmed that poor bone status reflects poor health. These data should be interpreted with caution because of the study limitations, especially the lack of representativity of the cohort and dropout of older and sick men. However, they suggest that older men with low BMD or accelerated bone loss should obtain detailed diagnostic assessment to establish general factors that can contribute to their poor bone status.

Intermittent PTH(1–34) does not increase union rates in open rat femoral fractures and exhibits attenuated anabolic effects compared to closed fractures

Intermittent Parathyroid Hormone (PTH)(1–34) has an established place in osteoporosis treatment, but also shows promising results in models of bone repair. Previous studies have been dominated by closed fracture models, where union is certain. One of the major clinical needs for anabolic therapies is the treatment of open and high energy fractures at risk of non-union. In the present study we therefore compared PTH(1–34) treatment in models of both open and closed fractures.108 male Wistar rats were randomly assigned to undergo standardized closed fractures or open osteotomies with periosteal stripping. 27 rats in each group were treated s.c. with PTH(1–34) at a dose of 50 μg/kg 5 days a week, the other 27 receiving saline. Specimens were harvested at 6 weeks for mechanical testing (n=17) or histological analysis (n=10).In closed fractures, union by any definition was 100% in both PTH(1–34) and saline groups at 6 weeks. In open fractures, the union rate was significantly lower (p<0.05), regardless of treatment. In open fractures the mechanically defined union rate was 10/16 (63%) in saline and 11/17 (65%) in PTH(1–34) treated fractures. By histology, the union rate was 3/9 (33%) with saline and 5/10 (50%) with PTH(1–34). Radiological union was seen in 13/25 (52%) for saline and 15/26 (58%) with PTH(1–34).Open fractures were associated with decreases in bone mineral content (BMC) and volumetric bone mineral density (vBMD) on quantitative computerized tomography (QCT) analysis compared to closed fractures. PTH(1–34) treatment in both models led to significant increases in callus BMC and volume as well as trabecular bone volume/total volume (BV/TV), as assessed histologically (p<0.01). In closed fractures, PTH(1–34) had a robust effect on callus size and strength, with a 60% increase in peak torque (p<0.05). In the open fractures that united and could be tested, PTH(1–34) treatment also increased peak torque by 49% compared to saline (p<0.05).In conclusion, intermittent PTH(1–34) produced significant increases in callus size and strength in closed fractures, but failed to increase the rate of union in an open fracture model. In the open fractures that did unite, a muted response to PTH was seen compared to closed fractures. Further research is required to determine if PTH(1–34) is an appropriate anabolic treatment for open fractures.

Effect of low level capacitive‐coupled pulsed electric field stimulation on mineral profile of weight‐bearing bones in ovariectomized rats

Mineral content, mineral composition, and crystalline pattern of bone in osteoporosis are different from those of normal individuals. Present management of bone mineral loss is rather unsatisfactory primarily because of socioeconomic factors and untoward effects of the treatment drugs. We report the efficacy of capacitive-coupled pulsed electric field (CCPEF) to prevent bone loss in an ovariectomized rat model of osteoporosis. One month postsurgery either leg was stimulated with CCPEF, whereas the other leg did not receive any stimulation (sham exposed). The treatment was given in 60 sessions each of 2 h/d (5 days a week). The control group of rats was sham operated. At the end of the observation period, femur and tibia bones were removed. Their bone mineral content (BMC), calcium, phosphorus, and carbon contents were analyzed and bone mineral density (BMD) was calculated. The BMC data were supported by X-ray diffraction (XRD) method. In sham-exposed bones, a statistically significant decrease in BMC, BMD, calcium, and phosphorus contents were obtained as compared to the control. Although in CCPEF bones, there was an attenuation of decrement in the noted parameters except phosphorus. XRD pattern supported these observations. The results suggest that chronic, 60 sessions of 2 h/d, 5 d/wk CCPEF (14 MHz with 16 Hz modulation 16 Hz and 10 V peak to peak) is effective in attenuating the ovariectomy-induced bone mineral loss in rats.

Changes in Bone Mineral Status and Bone Size During Pregnancy and the Influences of Body Weight and Calcium Intake

BACKGROUND Calcium may be mobilized from the maternal skeleton during pregnancy, which may be influenced by several factors. OBJECTIVE The objective was to investigate changes in bone mineral status and size during pregnancy and to consider the influences of body weight and calcium intake. DESIGN Thirty-four British women were studied before pregnancy and 2 wk postpartum (Preg). Eighty-four nonpregnant, nonlactating (NPNL) women were studied over a corresponding time. Bone mineral content (BMC), bone area (BA), areal bone mineral density (aBMD), and BA-adjusted BMC of the whole-body, lumbar spine, radius, and hip were measured by dual-energy X-ray absorptiometry. RESULTS The Preg group experienced significant decreases in BMC, aBMD, and BA-adjusted BMC at the whole-body, spine, and total hip of between 1% and 4%. Whole-body BMC increased in the NPNL group, and aBMD and BA-adjusted BMC decreased at the spine and hip by 0.5% to 1%. Whole-body BMC decreased in the Preg group by -2.16 +/- 0.46%, equivalent to -2.71 +/- 0.43% relative to the NPNL group (P < or = 0.001). Weight change was a positive predictor of skeletal change at the spine, hip, and radius in both groups. Differences between the Preg and NPNL groups in change in BA-adjusted BMC, after correction for weight change and other influences, were as follows (P < or = 0.01): whole-body, -1.70 +/- 0.25%; spine, -3.03 +/- 0.72%; and total hip, -1.87 +/- 0.60%. Calcium intake was not a significant predictor of skeletal change in either group. CONCLUSIONS Pregnancy is associated with decreases in whole-body and regional bone mineral status sufficient to make a sizeable contribution to maternal and fetal calcium economy. Calcium intake is not a significant predictor of the skeletal response to pregnancy in well-nourished women.

Changes in bone mineral status and bone size during pregnancy and the influences of body weight and calcium intake

Background: Calcium may be mobilized from the maternal skeleton during pregnancy, which may be influenced by several factors.Objective: The objective was to investigate changes in bone mineral status and size during pregnancy and to consider the influences of body weight and calcium intake.Design: Thirty-four British women were studied before pregnancy and 2 wk postpartum (Preg). Eighty-four nonpregnant, nonlactating (NPNL) women were studied over a corresponding time. Bone mineral content (BMC), bone area (BA), areal bone mineral density (aBMD), and BA-adjusted BMC of the whole-body, lumbar spine, radius, and hip were measured by dual-energy X-ray absorptiometry.Results: The Preg group experienced significant decreases in BMC, aBMD, and BA-adjusted BMC at the whole-body, spine, and total hip of between 1% and 4%. Whole-body BMC increased in the NPNL group, and aBMD and BA-adjusted BMC decreased at the spine and hip by 0.5% to 1%. Whole-body BMC decreased in the Preg group by −2.16 ± 0.46%, equivalent to −2.71 ± 0.43% relative to the NPNL group (P ≤ 0.001). Weight change was a positive predictor of skeletal change at the spine, hip, and radius in both groups. Differences between the Preg and NPNL groups in change in BA-adjusted BMC, after correction for weight change and other influences, were as follows (P ≤ 0.01): whole-body, −1.70 ± 0.25%; spine, −3.03 ± 0.72%; and total hip, −1.87 ± 0.60%. Calcium intake was not a significant predictor of skeletal change in either group.Conclusions: Pregnancy is associated with decreases in whole-body and regional bone mineral status sufficient to make a sizeable contribution to maternal and fetal calcium economy. Calcium intake is not a significant predictor of the skeletal response to pregnancy in well-nourished women.

Specific Effects of γ-Linolenic, Eicosapentaenoic, and Docosahexaenoic Ethyl Esters on Bone Post-ovariectomy in Rats

Long chain polyunsaturated fatty acids (LCPUFAs) are involved in the regulation of bone metabolism. Increased dietary consumption of n-3, and possibly some n-6, LCPUFAs may limit postmenopausal bone loss. The aim of this study was to determine the effects on bone of specific fatty acids within the n-3 and n-6 LCPUFA families in ovariectomized (OVX) rats. Rats were OVX or sham-operated and fed either a control diet (OVX and sham) or a diet supplemented with 0.5 g/kg body weight/day of gamma-linolenic (GLA), eicosapentaenoic (EPA), docosahexaenoic (DHA) ethyl esters or a mixture of all three (MIX) for 16 weeks. Bone mineral content (BMC), area, and density and plasma concentrations of insulin-like growth factor-I, vitamin D, selected biochemical markers of bone metabolism, and parathyroid hormone (PTH) were determined. The OVX-induced decrease in lumbar spine BMC was significantly attenuated by DHA but not by EPA or GLA supplementation or supplementation with a mixture of all three LCPUFAs. Endosteal circumferences of tibiae were significantly greater in DHA and EPA compared to OVX. Plasma C-terminal telopeptide of type I collagen and osteocalcin concentrations were not significantly different in the DHA group compared to OVX. Femur BMC decreased by a significantly greater amount in GLA than OVX, and final plasma PTH concentrations were significantly higher in GLA compared to all other groups. In conclusion, DHA ameliorated OVX-induced bone mineral loss. GLA exacerbated post-OVX bone mineral loss, possibly as a result of PTH-induced bone catabolism.

Modified activity-stress paradigm in an animal model of the female athlete triad

The exercising woman with nutritional deficits and related menstrual irregularities is at risk of compromising long-term bone health, i.e., the female athlete triad. There is no animal model of the female athlete triad. The purpose of this study was to examine long-term energy restriction in voluntary wheel-running female rats on estrous cycling, bone mineral content, and leptin levels. Twelve female Sprague-Dawley rats (age 34 days) were fed ad libitum and given access to running wheels during an initial 14-wk period, providing baseline and age-related data. Daily collection included dietary intake, body weight, estrous cycling, and voluntary running distance. At 4 mo, rats were randomized into two groups, six restrict-fed rats (70% of ad libitum intake) and six rats continuing as ad libitum-fed controls. Energy intake, energy expenditure, and energy availability (energy intake - energy expenditure) were calculated for each animal. Serum estradiol and leptin concentrations were measured by RIA. Femoral and tibial bone mineral density and bone mineral content (BMC) were determined by dual-energy X-ray absorptiometry. Restrict-fed rats exhibited a decrease in energy availability during Weight Loss and Anestrous phases (P = 0.002). Compared with controls after 12 wk, restrict-fed rats showed reduced concentrations of serum estradiol (P = 0.002) and leptin (P = 0.002), lower ovarian weight (P = 0.002), and decreased femoral (P = 0.041) and tibial (P = 0.05) BMC. Decreased energy availability resulted in anestrus and significant decreases in BMC, estrogen and leptin levels, and body weight. Finally, there is a critical level of energy availability to maintain estrous cycling.

What are the risk factors in the development of osteoarthritis following ACL reconstruction?

I would like to comment on the article by J.K. Seon et al. entitled “Osteoarthritis after anterior cruciate ligament reconstruction using apatellar tendon autograft” [4]. The authors investigated the development of osteoarthritis (OA) in patients who had their ACLs reconstructed using patellar tendon autograft. They determined the risk factors of OA to be: patient age over 25 years at the time of the operation, an interval between the injury and reconstruction of greater than 6 months, and additional meniscal injury [4]. As the follow-up period was long, we would like to know if the patients gained weight during follow-up, because weight increase affects the development of OA independently of the surgical procedure. The importance of increased weight and patient education has been reported previously [5]. The authors found no correlation between anterior instability or persistent subluxation and the developmentof OA in the long-term follow-up [4]. There are studies with much longer follow-ups that demonstrate that these factors increase the cartilage damage and thus osteoarthritis, making these people candidates for total knee replacement [1]. In a recent study, it was reported that the decrease of patellar tendon stiffness causes a decrease in bone mineral content and increases OA in patients who had undergone ACL reconstruction using patellar tendon allograft [2]. Although reconstructions using patellar tendon autograft and hamstring autograft gave similar clinical results, patellar tendon autograft is found to pose a greater risk of early development of OA [3]. In conclusion, although additional meniscal lesions, age and late reconstruction were blamed, patellar tendon autograft and an increase in weight are independent risk factors for osteoarthritis following ACL reconstruction.

Calcium supplementation during pregnancy and lactation: Effects on the mother and the fetus

Calcium consumption is essential for bone development and maintenance throughout life, yet more than one half of the female population in the United States does not consume the recommended amount of calcium. Calcium intake is especially crucial during pregnancy and lactation because of the potential adverse effect on maternal bone health if maternal calcium stores are depleted. There is often a transient lowered bone mineral density and increased rate of bone resorption, with the greatest consequence during the third trimester and throughout lactation. Studies indicate that calcium consumption should be encouraged, especially during pregnancy and lactation, to replace maternal skeletal calcium stores that are depleted during these periods. Because the fetus in utero and the neonate through breast-feeding are dependent on maternal sources for the total calcium load, adequate maternal calcium intake also can affect fetal bone health positively. Proper calcium consumption can be attained through the diet by the consumption of dairy products or leafy greens (such as kale), the consumption of fortified foods, or by supplementation with widely available calcium-containing supplement products. Because many women experience heartburn during pregnancy, calcium-based antacids are ideal for providing heartburn relief, and they offer a calcium supplement to ensure maternal and fetal bone health, without the danger of adverse effects on the neonate.

Bone status of Indian women from a low-income group and its relationship to the nutritional status

Indian women from low-income groups consume diets that have inadequate calcium coupled with too few calories, proteins and micronutrients. Hospital-based data suggest that these women have osteoporotic hip fractures at a much earlier age than Western women. Studies reporting bone parameters of the Indian population involving large sample sizes are not available. This study was therefore carried out with 289 women in the 30-60-year age group to estimate the prevalence of osteoporosis and measure the bone parameters by dual energy X-ray absorptiometry (DXA). Their mean (+/- SD) age was 41.0+/-8.60 years. Their mean (+/- SD) height, weight and body mass index (BMI) were 149.1+/-5.49 cm, 49.2+/-9.85 kg and 22.1+/-3.99, respectively. Dietary intake of calcium was estimated to be 270+/-57 mg/day. The prevalence of osteoporosis at the femoral neck was around 29%. Bone mineral density (BMD) and T scores at all the skeletal sites were much lower than the values reported from the developed countries and were indicative of a high prevalence of osteopenia and osteoporosis. BMD showed a decline after the age of 35 years in cases of the lumbar spine and femoral neck. This was largely due to a decrease of bone mineral content (BMC). The nutritional status of women appears to be an important determinant of bone parameters. BMD and BMC at all the skeletal sites and whole body increased significantly with increasing body weight and BMI of women (P<0.05). However, bone area (BA) did not change with an increase in BMI. In the multiple regression analysis, apart from body weight, age, menopause and calcium intake were the other important determinants of BMD (P<0.05). In addition to these, height was also an important determinant of WB-BMC. This study highlights the urgent need for measures to improve the nutritional status, dietary calcium intake and thus the bone health of this population.

The Monotonic and Fatigue Properties of Osteoporotic Thoracic Vertebral Bodies

Measurement of the monotonic and fatigue properties of osteoporotic thoracic vertebral bodies. To determine the loading values at which osteoporotic vertebral bodies are susceptible to failure. Vertebral compression fractures are the most common osteoporotic fracture. Eighty-three percent of vertebral compression fractures are caused by moderate or less trauma, and there is not a specific traumatic event in 59% of these cases. Fatigue loading can lead to premature failure, although the relationship between loading and cycles to failure is not well established. Eighteen osteoporotic thoracic vertebral bodies were tested in monotonic compression to determine the correlation between the bone mineral content and the ultimate compressive load. Seventeen osteoporotic thoracic vertebral bodies were cyclically loaded at varying percentages of the ultimate compressive load until failure to determine the relationship between loading and fatigue life. The bone mineral content was linearly correlated with ultimate compressive load. Based on our regression analysis, a 10% decrease in bone mineral content will lead to an approximate 10% decrease in ultimate compressive load. The percentage of ultimate compressive load was inversely correlated to the logarithm of cycles to failure, with specimens loaded at 60%, 70%, and 80% of ultimate compressive load lasting on average 5.6 x 10, 4.0 x 10, and 31 cycles to failure, respectively. The bone mineral content is a strong predictor of the ultimate compressive load, while the percentage of the ultimate compressive load is a strong predictor of the cycles to failure for osteoporotic thoracic vertebral bodies.

A Combination of Soft-Shell Turtle Powder and Essential Oil of a Unicellular Chorophyte Prevents Bone Loss and Decreased Bone Strength in Ovariectomized Rats

The effects of soft-shell turtle (Trionyx sinensis) powder (SST) on the proximal tibiae of ovariectomized (OVX) rats were investigated using peripheral quantitative computed tomography (pQCT) and examination of serum biochemical markers. Considering the relationship between the antioxidative property and antiosteoporotic activity, the synergistic effects of a mixture of SST and essential oil of the microalgae Haematococcus pluvialis (OHP) with strong antioxidant activity were also examined. Oral administration of SST (100, 200 mg/kg) or a mixture of SST (100, 200 mg/kg) and OHP (13, 26 mg/kg) three times weekly prevented the decrease in bone mineral content (BMC) in total bone, BMC and bone mineral density (BMD) in cortical bone, and bone strength indices induced by ovariectomy in a dose-dependent manner without uterine side effects. However, OHP alone showed no significant effects.

The Effect of Tamoxifen and Fluoride on Bone Mineral Density, Biomechanical Properties and Blood Lipids in Ovariectomized Rats

The most important aspect of therapy with fluoride and tamoxifen concerns its influence on bone tissue and lipid metabolism. The aim of the study was to evaluate the effect of tamoxifen and natrium fluoride (NaF) on bone metabolism, biochemical properties and blood lipids levels in ovariectomized rats. The study was performed in Wistar rats divided into 5 subgroups: ovariectomized controls, rats treated with NaF 20 mg/kg/24 hr, rats treated with NaF 20 mg/kg/24 hr+tamoxifen 2 mg/kg/24 hr, rats treated with NaF 20 mg/kg/24 hr plus tamoxifen 4 mg/kg/24 hr, and sham-operated controls. In ovariectomized rats the increase of total cholesterol, low-density lipoproteins cholesterol (LDL-cholesterol) as well as the decrease of bone mineral content, bone mineral density and biomechanical properties was observed. The therapy with NaF increased the level of total cholesterol, LDL-cholesterol, triglycerides, bone mineral density, bone mineral content. In this group the decrease of bone strength and stiffness was observed. The administration of tamoxifen reduced the changes in plasma lipid levels, but did not improve the biomechanical properties of bone tissue.

Effects of vitamin K 2 (menatetrenone) and alendronate on bone mineral density and bone strength in rats fed a low-magnesium diet

In this study, we examined changes in bone parameters and bone strength in rats fed low-Mg diets (experiment 1) and the effects of vitamin K 2 (MK-4, experiment 3) and alendronate (ALN, experiment 2) in this model. In experiment 1, 5-week-old male Wistar rats were fed three low-Mg diets (Mg 9, 6, 3 mg/100 g diet) for 4 weeks. Although the cortical bone mineral content (CtBMC) and cortical thickness (CtTh) of the femoral diaphysis in all low-Mg-diet groups were the same as or greater than those in the intact group (Mg: 90 mg/100 g diet), the maximum load and elastic modulus were significantly reduced in the 3-mg-Mg group. In experiment 2, 4-week-old Wistar rats were fed a 6-mg-Mg diet for 8 weeks, and the effect of ALN (2, 20, and 200 μg/kg twice a week) was evaluated. The administration of ALN at 200 μg/kg increased the cortical bone mineral content (CtBMC), CtTh, and maximum load, but had no effect on the elastic modulus, as compared with the low-Mg-control group. In experiment 3, the effect of MK-4 was evaluated under the same conditions as in experiment 2. The administration of MK-4 had no effect on CtBMC, CtTh, or bone components of the femoral diaphysis. However, MK-4 inhibited the decreases in maximum load and elastic modulus due to the low-Mg diet. Since there is no other experimental model in which there is a decrease in bone mechanical properties without a decrease in bone mineral content, the low-Mg diet model is considered to be an excellent model for examining bone quality. Our results from this model suggest that MK-4 and ALN affect bone mechanical properties by different mechanisms.

Effect of etodolac, a COX-2 inhibitor, on neuropathic pain in a rat model

Etodolac, a cyclooxygenase-2 inhibitor, may alleviate nociceptive pain and inhibit the activation of osteoclasts. The aim of the present study was to determine whether etodolac can alleviate heat-evoked hyperalgesia and investigate its possible protective effects on osteoporosis induced by chronic constriction injury (CCI) in rats. A CCI to the sciatic nerve was performed, after which the rats received etodolac orally in a volume of 2 ml at 0, 1, and 10 mg/kg/day for 1 to 5 weeks following surgery (experiment 1); at 0 and 10 mg/kg/day for 1 day to 5 weeks following surgery (experiment 2); and at 0 mg/kg/day for 1 to 5 weeks, 10 mg/kg/day for 1 to 2 weeks after surgery, or 10 mg/kg/day for 1 to 3 weeks after surgery (experiment 3). Paw withdrawal latency after exposure to heat, bone mineral content (BMC) and bone mineral density (BMD) in the whole tibial bone, and the number of tartrate resistant acid phosphate (TRAP)-positive multinucleated osteoclasts were measured. Etodolac alleviated heat-evoked hyperalgesia in the CCI rats and the increase in number of TRAP-positive multinucleated osteoclasts on the CCI-side was abrogated, however, it did not inhibit the decrease of BMC and BMD on the CCI-side. Our results suggest that etodolac is useful for treatment of neuropathic pain.