Dietary supplementation with glycosaminoglycans reduces locomotor problems in broiler chickens

This study aimed to assess the influence of glycosaminoglycan (chondroitin and glucosamine sulfates) supplementation in the diet on the performance and incidence of locomotor problems in broiler chickens. A completely randomized design was carried out in a 3 × 3 factorial scheme (3 levels of chondroitin sulfate -0, 0.05, and 0.10%; and 3 levels of glucosamine sulfate -0, 0.15, and 0.30%). Each treatment was composed of 6 replications of 30 broilers each. The performance of broilers (average weight, weight gain, feed intake, feed conversion, and productive viability) was assessed at 7, 21, 35, and 42 d of age, whereas the gait score, valgus and varus deviations, femoral degeneration, and tibial dyschondroplasia were assessed at 21 and 42 d of age. Increasing levels of glucosamine sulfate inclusion linearly increased the weight gain from 1 to 35 and from 1 to 42 d of age of broilers (P = 0.047 and P = 0.039, respectively), frequency of broilers with no femoral degeneration in the right and left femurs, and the proliferating cartilage area of proximal epiphysis at 42 d of age (P = 0.014, P < 0.0001, and P = 0.028, respectively). The increasing inclusion of chondroitin and glucosamine sulfates led to an increase in the frequency of broilers on the gait score scale 0 (P = 0.007 and P = 0.0001, respectively) and frequency of broilers with no valgus and varus deviations (P = 0.014 and P = 0.0002, respectively) also at 42 d of age. Thus, chondroitin and glucosamine sulfates can be used in the diet of broiler chickens to reduce their locomotor problems.

Protective effect of grape or apple juices in bone tissue of rats exposed to cadmium: role of RUNX-2 and RANK/L expression

The aim of this study was to investigate if grape or apple juices are able to protect bone tissue of rats exposed to cadmium. For this purpose, histopathological analysis and immunohistochemistry for RUNX-2 and RANK-L were investigated in this setting. A total of 20 adult Wistar rats were distributed into four groups (n = 5), as follows: control group, cadmium group, cadmium and grape juice group, and Cadmium and apple juice group. Control group received a single intraperitoneal (i.p.) water injection. Cadmium group received a single i.p. injection of cadmium chloride (1.2 mg/kg body weight) diluted in water. Cadmium and grape juice and cadmium and apple juice groups received a single i.p. injection of cadmium chloride (1.2 mg/kg body), and after 15 days, the rats were treated with grape or apple juices for 15 days, by gavage. All animals were euthanized 30 days after the beginning of experiment. Histopathological analysis in rat femur revealed extensive bone loss in rats intoxicated with cadmium. Grape or apple juices were able to increase bone formation. Cadmium inhibited RUNX-2 immunoexpression whereas cadmium increased RANK-L immunoexpression in rat bone cells. Grape or apple juices increased RUNX-2 and decreased RANK-L immunoexpression after cadmium intoxication. Taken together, our results demonstrate that grape or apple juices are able to exert therapeutic activity following cadmium intoxication in rat bone tissue as result of stimulatory effect of bone formation by RUNX-2 upregulation and RANK-L downregulation.

Vitamin D supplementation during pregnancy on infant anthropometric measurements and bone mass of mother-infant pairs: A randomized placebo clinical trial

INTRODUCTION

Based on the essential role of vitamin D in the regulation of calcium metabolism, we evaluated the effects of 2000IUvitamin D/day in late pregnancy on infant's anthropometric measurements and bone mass parameters of mother-infant pairs.

MATERIAL AND METHODS

In this randomized clinical trial, the main inclusion criteria were: aged 18 or older, no history of internal diseases and pregnancy complications, and a singleton live fetus. The intervention group received two 1000IU vitamin D₃ pills (2000IU) daily from weeks 26-28 until childbirth. Maternal serum 25-hydroxyvitamin D, infants' anthropometric measurements (at birth, 4th and 8th weeks postnatal), and maternal and infant bone mass parameters were examined.

RESULTS

The two groups were not statistically different in relation to baseline 25-hydroxyvitamin D concentrations. However, there was a significant difference between the study groups with regard to change in vitamin D status over time (p<0.001). In cross-sectional analysis, the two groups were not different with respect to anthropometric measurements in three time points. Also, in repeated measure analysis, the two groups did not show any statistical differences concerning the infants' anthropometric measurements. The bone mass measurements of all the 28 mothers who belonged to the two study groups were not different. Finally, the bones mass measurements of the infants in the two study groups were not different.

CONCLUSION

Ingestion of 2000IUvitamin D₃/day during late pregnancy did not improve anthropometric measurements of infants from birth until the 8th week postnatal, nor improve the maternal and infant bone mass measurements.

Pulsed electromagnetic fields inhibit bone loss in streptozotocin-induced diabetic rats

Evidences have shown that pulsed electromagnetic fields (PEMFs) can partially prevent bone loss in streptozotocin (STZ)-induced diabetic rats. However, the precise mechanisms accounting for these favorable effects are unclear. This study aimed to investigate the effects of PEMFs on bone mass and receptor activator of nuclear factor κB ligand (RANKL)/osteoprotegerin (OPG) and Wnt/β-catenin signaling pathway in STZ rats. Thirty 3-month-old Sprague Dawley rats were randomly divided into the following three groups (n = 10): control group (injection of saline vehicle), DM group (injection of STZ), and PEMFs group (injection of STZ + PEMFs exposure). One week following injection of STZ, rats in the PEMFs group were subject to PEMFs stimulus for 40 min/day, 5 days/week, and lasted for 12 weeks. After 12 week intervention, the results showed that PEMFs increased serum bone-specific alkaline phosphatase level and bone mineral density, and inhibited deterioration of bone microarchitecture and strength in STZ rats. Furthermore, PEMFs up-regulated the mRNA expressions of low-density lipoprotein receptor-related protein 5, β-catenin and runt-related gene 2 (Runx2), and down-regulated dickkopf1 in STZ rats. However, mRNA expressions of RANKL and OPG were not affected by PEMFs. PEMFs can prevent the diabetes-induced bone loss and reverse the deterioration of bone microarchitecture and strength by restoring Runx2 expression through regulation of Wnt/β-catenin signaling, regardless of its no glucose lowering effect.

Pulsed focused ultrasound treatment of muscle mitigates paralysis-induced bone loss in the adjacent bone: a study in a mouse model

Bone loss can result from bed rest, space flight, spinal cord injury or age-related hormonal changes. Current bone loss mitigation techniques include pharmaceutical interventions, exercise, pulsed ultrasound targeted to bone and whole body vibration. In this study, we attempted to mitigate paralysis-induced bone loss by applying focused ultrasound to the midbelly of a paralyzed muscle. We employed a mouse model of disuse that uses onabotulinumtoxinA-induced paralysis, which causes rapid bone loss in 5 d. A focused 2 MHz transducer applied pulsed exposures with pulse repetition frequency mimicking that of motor neuron firing during walking (80 Hz), standing (20 Hz), or the standard pulsed ultrasound frequency used in fracture healing (1 kHz). Exposures were applied daily to calf muscle for 4 consecutive d. Trabecular bone changes were characterized using micro-computed tomography. Our results indicated that application of certain focused pulsed ultrasound parameters was able to mitigate some of the paralysis-induced bone loss.

[Hepatic osteodystrophy in patients with liver cirrhosis]

The article presents research data of BMD in 106 patients with liver cirrhosis. The core group of examined patients presented with LC patients the etiology of alcohol--37.7% and primary biliary cirrhosis--35.8%. In 68.9% of patients with established deficits of bone mineral density, by 24.6%--at the level of osteoporosis. Was detected influence of the etiology of the disease on the frequency of osteopenia and osteoporosis containment. Was made analysis of dependence of the frequency of osteopenia, and/or osteoporosis of population risk factors, duration of disease, grade of liver failure on the Child-Pugh. A comparative assessment of the effectiveness treatment of disorders of BMD active metabolite of vitamin D3--alpha caltsidol and drugs from the group of bisphosphonates.

[Bone metabolism disturbances in anorexia nervosa]

Osteoporosis is a frequent complications of anorexia nervosa (AN). The etiology of osteoporosis in AN is multifactorial. Multiaxial hormonal disturbances and chronic undernutrition cause decrease or the lack of increase of bone mineral density (BMD), expected in adolescence. Both processes result from increased resorption and insufficient bone formation and/or mineralization. Decreased BMD persist in adult patients with a history of AN in the adolescence. There are no guidelines concerning treatment of osteoporosis in AN. The authors present review of the literature concerning bone metabolism in AN.

Treatment with leuprolide acetate and hormonal add-back for up to 10 years in stage IV endometriosis patients with chronic pelvic pain

This pilot study examined the effect of a low-dose E and pulsed progestogen hormone therapy (HT) regimen for add-back during long-term GnRH-agonist therapy on bone mineral density (BMD) in five patients with stage IV endometriosis. Bone mineral density was stable after initiation of HT for the entire follow-up period (up to 10 years). One patient stopped her treatment on two occasions to conceive and was successful each time with delivery of a normal baby. No patient had return of pelvic pain after HT add-back.

Exercise and pharmacological countermeasures for bone loss during long-duration space flight

Bone loss in the lower extremities and lumbar spine is an established consequence of long-duration human space flight. Astronauts typically lose as much bone mass in the proximal femur in 1 month as postmenopausal women on Earth lose in 1 year. Pharmacological interventions have not been routinely used in space, and countermeasure programs have depended solely upon exercise. However, it is clear that the osteogenic stimulus from exercise has been inadequate to maintain bone mass, due to insufficient load or duration. Attention has therefore been focused on several pharmacological interventions that have been successful in preventing or attenuating osteoporosis on Earth. Anti-resorptives are the class of drugs most commonly used to treat osteoporosis in postmenopausal women, notably alendronate sodium, risedronate sodium, zoledronic acid, and selective estrogen receptor modulators, such as raloxifene. There has also been considerable recent interest in anabolic agents such as parathyroid hormone (PTH) and teriparatide (rhPTH [1-34]). Vitamin D and calcium supplementation have also been used. Recent studies of kindreds with abnormally high bone mineral density have provided insight into the genetic regulation of bone mass. This has led to potential therapeutic interventions based on the LRP5, Wnt and BMP2 pathways. Another target is the RANK-L/osteoprotegerin signaling pathway, which influences bone turnover by regulating osteoclast formation and maturation. Trials using such therapies in space are being planned. Among the factors to be considered are dose-response relationships, bone quality, post-use recovery, and combination therapies--all of which may have unique characteristics when the drugs are used in space.

Depot medroxyprogesterone acetate, oral contraceptives and bone mineral density in a cohort of adolescent girls

PURPOSE

To conduct a longitudinal comparison of bone mineral density (BMD) in 370 adolescent girls, aged 12-18, who self-selected depot medroxyprogesterone acetate (DMPA) or an oral contraceptive (OC) containing 20 microg ethinyl estradiol/100 microg levonorgestrel with that in girls who received no hormonal treatment (control group).

METHODS

Lumbar spine and femoral neck BMD measurements were obtained by dual energy x-ray absorptiometry at baseline and 12 months. Data were analyzed with repeated measures analysis of covariance methods.

RESULTS

Over 12 months, lumbar spine BMD decreased in the DMPA group (n = 29), with a mean percent change of -1.4% (95% confidence interval [CI] -2.73, -0.10), and increased by a mean of 3.8% (95% CI 3.11, 4.57) in the control group [n = 107 (p < .001)]. The increase in mean percent change in lumbar spine BMD in the OC group (n = 79), 2.3% (95% CI 1.49, 3.18), was significantly smaller than in the control group (p = .03). Over 12 months, the mean percent change in femoral neck BMD was -2.2% (95% CI -3.95, -0.39) in the DMPA group, but increased 2.3% (95% CI 1.29, 3.27) in the control group (p < .001). The increase in mean percent change at the femoral neck in the OC group, 0.3% (95% CI -0.87, 1.41), was significantly lower than in the control group (p = .03).

CONCLUSIONS

Our study contributes to an increasing body of knowledge indicating a negative impact of DMPA on bone health in young women. Additional findings suggest a potential adverse effect of an OC containing 20 microg ethinyl estradiol/100 microg levonorgestrel on bone health in adolescents.

Effect of centrifuge-induced artificial gravity and ergometric exercise on cardiovascular deconditioning, myatrophy, and osteoporosis induced by a -6 degrees head-down bedrest

We have reported that centrifuge-induced artificial gravity with ergometric exercise could reduce developing cardiovascular deconditioning in humans. In the present study, we examined this load could prevent the myatrophy and osteoporosis induced by head-down bedrest for 20 days. Subjects were ten healthy male volunteers with informed consent. They were requested to lie down at -6 degrees for 20 days, and evaluation for cardiovascular deconditioning, myatrophy, and osteoporosis. As the result, high G-load with low intensity exercise suppressed the orthostatic intolerance and increase in serum osteoporotic marker, whereas low G-load with high intensity ergometric exercise maintained the maximal oxygen intake, heart dimension, and prevented myatrophy. The combination of high/low G-load with low/high intensity exercise will determine the optimal protocol for prevention of cardiovascular deconditioning, myatrophy, and osteoporosis.

Daily 4-h head-up tilt is effective in preventing muscle but not bone atrophy due to simulated microgravity

To assess the potential value of intermittent artificial gravity as an efficient countermeasure, our previous studies have showed that daily 4-h standing (STD) is sufficient in counteracting muscle atrophy but not bone atrophy induced by simulated microgravity. The aim of the present study was to determine whether intermittent gravitational loading by daily 2-h or 4-h, +45 degrees head-up tilt (HUT) is more effective than STD in counteracting muscle and, particularly, bone atrophy due to simulated microgravity. Sprague-Dawley male rats weighing 290-300 g were subjected to a 28-d tail-suspension to simulate microgravity deconditioning. Daily HUT for 2, or 4 h was used to provide intermittent gravitational loading in foot-ward and tail-ward directions. The results showed that 4 h/d HUT was sufficient, and 2 h/d was less effective, in preventing adverse changes in muscle weights, fiber types, and cross-sectional areas (CSA) of muscles due to a 28-d simulated microgravity. The % protections by 4 h/d HUT in maintaining the CSAs of type I fibers in soleus, medial and lateral gastrocnemius and extensor digitorum longus muscles were 103%, 82%, 102%, and 83%, respectively. However, according to changes in physical and mechanical properties of femur, daily 4-h HUT was ineffective in attenuating the adverse changes in bone due to a 28-d simulated microgravity. Reductions in wet, dry, and ash weights and decreases in mechanical strength of femur did not show significant improvement by daily 2-h or 4-h HUT. Taken together, the findings indicate that the countermeasure effectiveness of daily 2-h or 4-h HUT for muscles is comparable with that by daily STD with the same durations. Daily 4-h HUT, as 4-h STD, is also ineffective in attenuating adverse changes in bone mass, but seems partially effective in preventing declines in mechanical properties due to simulated microgravity.

[Changes in bone density in hemodialysed women treated with transdermal hormone replacement therapy]

OBJECTIVES

Renal insufficiency in women can cause menstrual disturbances and changes of hormonal profile leading to the decrease of bone mass density. Drug administration during dialysis also influences the bone density and increases the risk of osteoporosis. The aim of the study is to assess the effect of transdermal hormonal replacement therapy (HRT) in hemodialysed patients with secondary amenorrhea on bone density.

MATERIAL AND METHODS

10 women aged from 22 to 45 years old were enrolled in the study. They received 17 beta-estradiol and norethisterone acetate in patches during 12 cycles. Densitometer of lumbar spine and serum estradiol concentration were measured before and after 12 cycles of therapy.

RESULTS

The recurrence of regular vaginal bleeding, the increase of estradiol levels and bone mass density rate about 6% were observed.

CONCLUSIONS

Transdermal hormonal replacement therapy in hemodialysed women with secondary amenorrhea revealed the efficacy of the treatment and prevention from osteoporosis.

The importance of exercising in space

As a direct consequence of exposure to microgravity, astronauts experience a set of physiological changes which can have serious medical implications when they return to earth. Most immediate and significant are the headward shift of body fluids and the removal of gravitational loading from bone and muscles, which lead to progressive changes in the cardiovascular and musculoskeletal systems. Cardiovascular adaptations result in an increased incidence of orthostatic intolerance (fainting) following flight, decreased cardiac output, and reduced capacity for exercise. Changes in the musculoskeletal system contribute significantly to impaired function experienced in the post-flight period. The underlying factor producing these changes is the absence of gravity, and countermeasures are therefore designed primarily to simulate earthlike movements, stresses, and system interactions. Exercise is one approach that has had wide operational use and acceptance in both the US and Russian space programmes, and it has enabled humans to stay relatively healthy in space for well over a year. Although it remains the most effective countermeasure currently available, significant physiological degradation still occurs. The development of other countermeasures will be necessary for missions of longer duration, for example for human exploration of Mars.

The physical price of a ticket into space

As a direct consequence of exposure to microgravity astronauts experience a number of physiological changes, which can have serious medical implications when they return to Earth. Most immediate and significant are the head-ward shift of body fluids and the removal of gravitational loading from bone and muscles, which lead to progressive changes in the cardiovascular and musculoskeletal systems. Cardiovascular adaptations result in an increased incidence of orthostatic intolerance (fainting) post-flight, decreased cardiac output and reduced exercise capacity. Changes in the musculoskeletal system contribute significantly to the impaired functions experienced in the post-flight period. The underlying factor producing these changes is the absence of gravity. Countermeasures, therefore, are designed primarily to simulate Earth-like movements, stresses and system interactions. Exercise is one approach that has received wide operational use and acceptance in both the US and Russian space programmes, and has enabled humans to stay relatively healthy in space for well over a year. Although it remains the most effective countermeasure currently available, significant physiological degradation still occurs. The development of other countermeasures will therefore be necessary for longer duration missions, such as the human exploration of Mars.

[Preventive effects of exercise training on bone loss during 21 d -6 degrees head down bed-rest]

OBJECTIVE

To observe the protective effects of exercise training during 21 d -6 degrees head down bed rest (HDBR) on bone loss.

METHOD

Ten healthy young men were randomly divided into HDBR group and HD-BR exercise group, with 5 in each group. Both groups were exposed to -6 degrees head down bed rest for 21 d. The subjects in the exercise group performed exercise with a bicycle ergometer in supine position 1 h/d during bed rest. Femur bone mineral density (BMD), serum bone gla protein (BGP) as well as hydroxyproline/creatinine (HOP/Cr) were determined before and during 20 d HDBR.

RESULT

As compared with the before HDBR values, average femur BMD decreased by 5.8% and 0.9% for HDBR group and HDBR and exercise group respectively. HOP/Cr significantly increased in the HDBR group and was significantly higher than the HDBR exercise group. BGP decreased in both groups with no significant difference.

CONCLUSION

Exercise during 21 d -6 degrees HDBR is beneficial in preventing bone loss.

Calcium metabolism under stress and in repose

Derangement of calcium metabolism, although perhaps not as dramatic as that of the cardiovascular or vestibular systems, constitutes one of the major threats to the health of participants in exploration of space. On the basis of studies in immobilized subjects, the clinical disorders most likely to be encountered during prolonged space flight are primarily the consequence of an imbalance between bone formation and resorption (favoring the latter): (1) loss of skeletal mass, leading to osteoporosis; (ii) hypercalcemia; and (iii) hyper-calciuria, with the attendant risk of nephrolithiasis. By itself, loss of skeletal mass would not be expected to pose an in-flight hazard, but hypercalcemia or nephrolithiasis could jeopardize lives or mission success. Such data as are available from in-flight studies tend to support the use of immobilization as a terrestrial model for alterations in calcium metabolism during space flight. A variety of prophylactic measures have been attempted with this model in an effort to modify the observed disorders. Although there is some evidence that hypercalcemia and hypercalciuria can be reduced or prevented, negative calcium balance has not been completely reversed. Perhaps the most successful prophylactic measure utilized to date has been dietary supplementation of both calcium and inorganic phosphate. With the wide variety of excellent study tools which are currently available for application to this field, significantly increased efforts are clearly required both to define the basic mechanism of immobilization-induced skeletal losses and to devise new prophylactic or therapeutic approaches.

Effects of periodic weight support in a simulated weightless environment in preventing bone demineralisation

Anti Orthostatic Hypokinetic posture in rats by tail suspension for 15 days (d) simulates the deconditioning effects of weightlessness on the weight bearing bones. The present study evaluates the effects of daily 4 hour (h) weight support (WS) during simulated weightlessness (S-W) in preventing these changes. Adult male albino rats were divided into three groups as (i) Control (CON, n = 12), (ii) Hind limb unweighing by tail suspension for 15 d (HU, n = 18), (iii) HU with daily 4 h WS (4 HRWS, n = 11). After 15 d tibia from all the animals were removed and subsequently dried, ashed and then calcium content of the bones were determined. HU showed reductions in the water content by 35.8%, organic matrix by 12.2% and calcium content by 33.4% of tibia. 4 h WS during S-W resulted in complete prevention of water loss and organic matrix loss and partial prevention of the loss of calcium content. Calcium content of tibia in 4 HRWS remained 15.2% less as compared to CON. These findings indicate that 4 h WS is partially successful in preventing the demineralisation effects of S-W on weight bearing bone tibia.

Biomedical results of the Skylab Program

Skylab, the fourth in a logical sequence of USA manned space flight projects following Mercury, Gemini and Apollo, presented life scientists with their first opportunity for an in-depth study of man's response to the space environment. Extensive medical investigations were undertaken to increase our understanding of man's adaptation to the space environment and his readaptation to gravity upon return to earth. The flight durations of the three Skylab missions were progressively increased from 28 days to 59 days and, finally, 84 days. The results of these investigations of the various body systems clearly demonstrated that man can adapt to zero gravity and perform useful work during long-duration space flight. However, definite changes (some unexpected) in the vestibular, cardiovascular, musculo-skeletal, renal and electrolyte areas were documented. The most significant were: the occurrence of space motion sickness early in the missions; diminished orthostatic tolerance, both in-flight and post-flight; moderate losses of calcium, phosphorus and nitrogen; and decreased tolerance for exercise post-flight. The mechanisms responsible for these physiological responses must be understood and, if necessary, effective countermeasures developed before man can endure unlimited exposure to space flight.

[One year observation on effects of estrogen, tamoxifen combined with or without fluoride on preventing bone loss in ovariectomized rats]

OBJECTIVE

To compare the effects of one year treatment of estrogen and tamoxifen, either alone or combined with fluoride on bone metabolism in ovariectomized rats.

METHODS

One hundred and forty two virgin female Sprague-Dawley rats were ovariectomized (OVX) or sham operated at 6 months of age, and randomly divided into 7 groups (19 - 21 rats each): (1) sham-operated controls; (2) OVX vehicle controls; (3) estrogen group; (4) fluoride group; (5) tamoxifen group; (6) fluoride plus estrogen; (7) fluoride plus tamoxifen. The treatments lasted for one year. Bone mineral density (BMD) measurement, bone histomorphometry analysis (lumbar vertebrae) and biomechanical test (3-point-bending test on right femur) were performed before and after treatment. The histological change of uterus were also determined at the same time.

RESULTS

(1) Twelve months of ovariectomy, the OVX group had significantly lower total body (279 mg/cm(2)), lumbar vertebra (232 mg/cm(2)) than all other groups (total body 286 - 298 mg/cm(2), lumber 251 - 266 mg/cm(2), P < 0.05). Estrogen group (216 mg/cm(2)) had higher BMD than tamoxifene group (195 mg/cm(2)) in midshaft of femur. (2) After 4 months of ovariectomy, only the two combination groups kept the maximum load (145 N) of right femur over the level of OVX group (118 N); after 12 months of treatment, the maximum load of OVX group [(108 +/- 13) N] was significantly different from all other groups (132 - 155 N); both maximum load and elastic load of estrogen group were significantly higher than that of tamoxifen group. (3) No evidence of dysmineralization was found by bone histomorphometry.

CONCLUSIONS

Estrogen has more potent effects on keeping bone mass and bone strength as compared with tamoxifene. The combined therapy (estrogen + fluoride or tamoxifen + fluoride) resulted in better bone strength than the single ones.

Long-term impact of chemotherapy-induced ovarian failure on bone mineral density (BMD) in premenopausal breast cancer patients. The effect of adjuvant clodronate treatment

We present the 5-year results of the effect of adjuvant chemotherapy on bone mineral density (BMD) and the efficacy of clodronate in the prevention of bone loss in 73 premenopausal women with primary breast cancer. All patients were treated with cyclophosphamide, methotrexate, 5-fluorouracil (CMF) chemotherapy. The patients were randomised to oral clodronate 1600 mg daily for 3 years or to a control group. At 5 years, patients were divided into those with preserved menstruation and those with amenorrhoea. Changes in BMD correlated significantly with the menstrual function after chemotherapy. The change in the lumbar spine BMD at 3 and 5 years were +0.6 and -1.3% in the menstruating group and -7.5 and -10.4% in the amenorrhoeic group (P=0.0001 and 0.0001, respectively), and in femoral neck +1.7 and -0.3%, and -3.5 and -5.8% (P=0.002 and P=0.001, respectively). Three-year clodronate treatment significantly reduced the bone loss in the lumbar spine -3.0% compared with controls -7.4% at three years (P=0.003), but no significant difference was found in the femoral neck: -1.7% versus -2.8%, respectively (P=0.86). These differences between the study groups were still seen at 5 years: in the lumbar spine -5.8% versus -9.7% (P=0.008) and femoral neck -3.5% versus -5.1% (P=0.91). In conclusion, chemotherapy-induced ovarian failure in premenopausal women caused a temporary accelerated bone loss of the lumbar spine. Adjuvant clodronate treatment significantly reduced this bone loss. Two years after the termination of treatment, the bone loss was still significantly less in the clodronate group compared with the control group.

Countermeasure development: future research targets

We will briefly discuss a series of countermeasures that are currently being developed to maintain bone mass and the integrity of supporting connective tissues. Our objective is to focus on several countermeasures under development which can be tested on the ISS. Other countermeasures may also be needed to provide additional safety factors which are required before long duration spaceflight is undertaken.

[Effect of gravitation loading and retabolil on development of atrophy in muscles and bones of rats due to suspension]

In a 3-wk experiment with tail-suspended rats histological and histomorphometric methods were used to determine the effects of graded gravitational loading (GGL) and anabolic steroid retabolil (nortestosterone decanoate) on the course of atrophy in soleus m. (SM), gastrocnemius m. (GM), tibia and humerus, and functioning of somatotrophic hormones (STH) of the pituitary and thyrocytes of the thyroid. Suspension was found to produce atrophy in SM and, to a less degree, in GM, partial transformation of SM slow fibers into the fast ones, suppression of the tibial longitudinal growth, demineralization of the tibial and humeral spongious metaphyses; besides, functional activities of STH-cells and thyrocytes were inhibited. Graded gravitational loading of rats by intermittence of suspension for 2 hrs slowed down atrophy in both muscles and osteopenia in tibia, stimulated the synthetic and secretory functions of STH-cells without any marked effect on thyrocytes or humeral osteopenia. GGL failed to influence the slow-to-fast transformation of SM fibers. Two injections of retabolil at the total dose of 3 mg/kg of the body mass somewhat interfered with the SM atrophy and humoral osteopenia, and were favorable to the synthetic but not secretory activity of STH-cells. Neither SM and tibial atrophies nor thyroid activity of the gland were improved. The prophylactic action of GGL upon the SM and humeral atrophies was significantly higher when combined with retabolil, whereas GM and tibia were not noticeably cured by retabolil. Inhibition of the SM atrophy and humeral osteopenia in rats treated with GGL and retabolil concurred with elevated activities of STH-cells and thyrocytes indirectly suggesting their more intensive production of the growth hormone and thyroid hormones, respectively.

[Bone mass evolution in patients with precocious and advanced puberty treated with LHRH analogs]

OBJECTIVE

Our aim was to know the long-term effects of treatment with LHRH analogs on the bone mass of patients with precocious or advanced puberty.

PATIENTS AND METHODS

Forty-six patients (11 boys and 35 girls) received a-LHRH throughout a 2-year period. The diagnoses were precocious or advance puberty alone or associated to other pathologies. The bone mass was indirectly estimated by measuring the cortical thickness (CT) and the metacarpal diameter (BD) of the 2nd, 3rd, and 4th metacarpals, taking as a reference values the results of the longitudinal Aragonese study of the "Andrea Prader" Center.

RESULTS

The CT was 1.3 SD at the beginning and decreased to 0.3 SD (p < 0.002) by the end of therapy and continuing losing to reach 0.1 SD after withdrawal. The BA decreased from 0.8 SD to 0.7 SD (p < 0.0002) and continued decreasing to reach 0.5 SD after withdrawal (p < 0.05). The BD went from -0.64 to -0.62 and to -0.9 SD (p < 0.04) after withdrawal. The longitudinal study of the same 18 cases gave similar results. No significant difference was found between sexes.

CONCLUSIONS

In precocious or advance puberty, the bone age and the cortical thickness are increased. After two years of treatment with a-LHRH both decreased significantly and stabilized one year after its suppression. The BD does not change during the treatment, but continues losing value thereafter. This loss of bone mass, not well known in this pediatric situation, is probably related to estrogen deprivation and needs the attention of the physician in order to take possible preventative measures.

[Bone demineralization in Crohn's disease, its diagnosis, therapy and prevention]

In 20-60% of patients with Crohn's disease bone demineralization is found, usually osteoporosis, but also osteoporosis with malatic features. The cause is the reduced calcium intake (loss of appetite, lactose intolerance and malabsorption), reduced vitamin D intake and corticoid therapy. Nowadays the diagnosis is facilitated by the use of densitometers (ultrasonic and DEXA) and markers of osteoresorption and new bone formation. In treatment in addition to calcium and vitamin D used for a long time, fluorides are administered (only as monofluorophosphate), nasal thyrocalcitonin and bisphosphonates of the third series (alendronate). In postmenopausal women also hormonal treatment can be used unless contraindicated. However, burdening of the bones with regular exercise is a necessity. For prevention adequate calcium and vitamin D intake is important, non-smoking, and exercise.

[The prevention of bone mineral loss with hormonal replacement therapy in premenopausal women on dialysis with estrogen deficiency]

In 25-30% of premenopausal dialysis women low serum estrogen concentrations are observed. This "premature menopause" can significantly contribute to accelerated bone loss. The aim of the study was to evaluate the effect of estrogen-gestagen replacement therapy on bone mineral density (BMD) in hemodialysis women with secondary to uremia estrogen deficiency. Among 20 hemodialysis women, aged 18-45 years, with serum 17 beta-estradiol < 30 pg/ml, ten (group I) received transdermal estradiol with cyclic addition of noretisterone acetate (Estracomb TTS 50/0.25), and another ten formed the control group (group II). BMD was evaluated by dual photon x-ray absorptiometry (DEXA, Lunar) in: lumbar spine (L2-L4), 1/3 distal radius and femoral neck, before and after the study. Serum 17 beta-estradiol concentrations were measured before, and after 1, 3, 6 and 12 months of the study. After one year, in group I, in which serum 17 beta-estradiol normalized already during the first month (p < 0.001), an increase of in BMD was noted, although significant only in L2-L4 (p < 0.05). In group II, no change in serum 17 beta-estradiol and mild but insignificant decrease in BMD were observed. However, a comparison of BMD values after 12 months in both groups revealed the marked differences in all studied sites (p < 0.01, p < 0.02, p < 0.05 in L4-L2, distal radius and femoral neck, respectively). The mean serum calcium, phosphate, PTH and alkaline phosphatase activity were similar in both groups and did not change during the study. In premenopausal hemodialysis women with estrogen deficiency, hormonal replacement therapy inhibits bone demineralization and can be useful in prevention of early osteoporosis.

Prevention of bone demineralization by calcium supplementation in precocious puberty during gonadotropin-releasing hormone agonist treatment

We have previously demonstrated a negative impact on peak bone mass in girls with precocious puberty treated with GnRH agonist (GnRHa). Several studies have shown that a high calcium intake positively influences bone mass in prepubertal girls and leads to a higher peak bone mass. The aim of this study was to evaluate the effect of calcium supplementation in girls with precocious puberty during GnRHa treatment. Forty girls affected by true central precocious puberty and treated with the GnRHa triptorelin were studied for 2 yr. After diagnosis, the patients were randomly assigned to three groups: group A, treated only with GnRHa; group B, treated for 12 months solely with GnRHa and then supplemented with calcium gluconolactate/carbonate (1 g calcium/day in two doses) for 12 months; and group C, treated from the beginning with combined GnRHa and calcium. Bone mineral density (BMD) at the lumbar spine was measured by dual energy x-ray absorptiometry at the beginning of the study and after 12 and 24 months and was expressed as the calculated true volumetric density (BMDv) in milligrams per cm3. Group A showed a decrease in absolute BMDv levels, in SD score for chronological age (CA), and even more in SD score for bone age (BA). Group B showed the same behavior during the first year, but this trend was reversed in the second year, when calcium supplementation was added to GnRHa treatment. Group C showed an increase in absolute BMDv levels and in SD score for CA and BA. BMDv variations (expressed as absolute values, SD score for CA, and SD score for BA) became statistically significant at 24 months between groups C and A (P = 0.036, P = 0.032, and P = 0.025, respectively). The behavior of the lumbar spine BMDv in the three groups is consistent with a positive effect of calcium supplementation during GnRHa treatment. In calcium-supplemented patients, the normal process of bone mass accretion at puberty is preserved despite GnRHa treatment. Therefore, the reduction in BMD during GnRHa treatment in girls with precocious puberty is at least completely reversible and preventable if calcium supplementation is associated from the beginning.

Bone loss during long term space flight is prevented by the application of a short term impulsive mechanical stimulus

In long term space flight, the mechanical forces applied to the skeleton are substantially reduced and are altered in character. This reduced skeletal loading results in a reduction in bone mass. Exercise techniques currently used in space can maintain muscle mass but the mechanical stimulus provided by this exercise does not prevent bone loss. By applying an external impulsive load for a short period each day, which is intended to mimic the heel strike transient, to the lower limb of an astronaut during a long term space flight (5 months), this study tests the hypothesis that the bone cells can be activated by an appropriate external mechanical stimulus to maintain bone mass throughout prolonged periods of weightlessness. A mechanical loading device was developed to produce a loading of the os-calcis similar to that observed during the heel strike transient. The device is activated by the astronaut to provide a transient load to the heel of one leg whilst providing an equivalent exercising load to the other leg. During the EUROMIR95 mission on the MIR space station, an astronaut used this device for a short period daily throughout the duration of the mission. Pre- and post-flight measurements of bone mineral density (BMD) of the os-calcis and femoral neck of the astronaut were made to determine the efficacy of the device in preventing loss of bone mineral during the mission. On the os-calcis which received the mechanical stimulus, BMD was maintained throughout the period of the flight, while it was reduced by up to 7% on the os-calcis which received no stimulus. Post-flight, BMD in both the stimulated and non-stimulated os-calcis reduces, the extent of this reduction however is less in the stimulated os-calcis. For the femoral neck, the mechanical stimulation does not produce a positive effect.

Administration of bisphosphonate prevents disuse bone atrophy induced by tail suspension

We recently demonstrated that osteopenia induced by rat tail-suspension was associated with an initial increase in bone resorption. To study the significance of the increase in early bone resorption for osteopenia, we investigated whether administration of YH529, a third-generation bisphosphonate, prevents the development of osteopenia as evidenced by increased wet weight of the femur, together with its calcium and phosphorus contents, when compared with those of tail-suspended rats treated with the vehicle alone. These results suggested that the initial increase in bone resorption plays an important role in the development of osteopenia induced by tail suspension.

Effect of bisphosphonate administration on the excretion of stress hormones in tail-suspended rats

We demonstrated that administration of a bisphosphonate, YH529, prevents the development of disuse atrophy of the hind limbs induced by tail-suspension in rats. Since tail suspension is accompanied by an increase in the secretion of stress hormones, we studied whether administration of bisphosphonate affects the secretion of stress hormones during that procedure. Tail suspension was carried out in a metabolic cage by connecting a wire inserted through tail bone to the ceiling of the cage. The control rat received the same treatment but was not suspended. YH529 or a vehicle (PBS=phosphate buffered saline) was administered daily starting 3 days before the commencement of tail suspension. Urine samples were collected before the wire was inserted (day 0), on the day of insertion (day 1) and 3, 5 and 7 days after. In the control rats receiving PBS, urinary excretion of corticosterone and epinephrine did not change throughout the 7-day experimental period. In the control rats receiving YH529, urinary excretion of corticosterone increased significantly on the day of tail-piercing and wiring but then returned to the prior level. This increase was not observed in the control group receiving PBS. In the tail suspended rats, excretion of corticosterone and epinephrine increased significantly in both PBS and YH529 groups, the highest level being observed on the first day of tail suspension. Although statistically not significant, corticosterone excretion on day 1 of tail suspension was higher in the YH529 groups than that in the PBS group. It is thus suggested that administration of YH529 causes an augmented response to stress load.

Effect of vitamin K2 (menaquinone-7) on bone metabolism in the femoral-metaphyseal tissues of normal and skeletal-unloaded rats: enhancement with zinc

The effect of vitamin K2 (menaquinone-7) on bone metabolism in the femoral-metaphyseal tissues of normal and skeletal-unloaded rats was investigated. Skeletal unloading was designed using a model of hindlimb suspension; the rats were fed for the 4 days of unloading. The metaphyseal tissues obtained from normal and skeletal-unloaded rats were cultured for 48 h in medium containing either vehicle or vitamin K2 (10(-6) and 10(-5) M). The presence of vitamin K2 (10(-5) M) caused a significant increase in alkaline phosphatase activity and calcium content in the metaphyseal tissues from normal rats. Such an effect was not seen in the bone tissues from skeletal-unloaded rats. Additionally, the presence of zinc sulfate (10(-5) M) in effective concentration produced a significant increase in alkaline phosphatase activity and calcium content in the metaphyseal tissues from normal and skeletal-unloaded rats. In the presence of vitamin K2 (10(-5) M), the stimulatory effect of zinc sulfate on bone calcium content was appreciably enhanced; although this effect was completely abolished by cycloheximide (10(-6) M), an inhibitor of protein synthesis. This study demonstrates that the effect of vitamin K2 (menaquinone-7) on trabecular bone calcification in rats with skeletal unloading-induced osteopenia is enhanced by zinc in vitro. The enhancement with zinc may be based on a newly synthesized protein in the bone tissues.

Is continuous intranasal salmon calcitonin effective in treating axial bone loss in patients with active rheumatoid arthritis receiving low dose glucocorticoid therapy?

OBJECTIVE

To investigate the efficacy of intranasal salmon calcitonin (sCT) in treating axial bone loss in patients with rheumatoid arthritis (RA) taking low dose glucocorticoids.

METHODS

In this open, multicenter study 32 women with RA were treated one year with sCT 100 IU/day and calcium (Ca) 500 mg/day; 31 women were treated with Ca alone. Bone mineral density (BMD) was measured at the lumbar spine and proximal femur (femoral neck, Ward's triangle, trochanter) before sCT therapy and again after 6 and 12 months.

RESULTS

Among valid completers treated with sCT and Ca (n = 26), the mean BMD increased at the lumbar spine (L1-L4), femoral neck, and Ward's triangle. In contrast, valid completers treated with Ca (n = 23) showed bone loss at the spine (L1-L4), femoral neck, Ward's triangle, and trochanter area. The differences of the changes in BMD were statistically significant between these groups at the femoral neck, Ward's triangle, and trochanter. There were no significant differences between groups in bone loss over 12 months at the lumbar spine (L1-L4), although analysis of the upper segment (L1-L2) suggested some possible benefit of sCT.

CONCLUSION

Intranasal sCT (100 IU/day) appears to have beneficial effects on bone loss at the proximal femur in patients with active RA treated with low dose glucocorticoids for 12 months; longer studies are needed to exclude transient bone remodelling effects.

Effects of bisphosphonate on bone metabolism in tail-suspended rats

Our previous studies demonstrated that tail suspension causes early, transient increases in osteoclastic activity, followed by a decrease in osteoblastic activity in the hind limbs of rats. To assess whether this early increase in bone resorption is important in the development of disuse atrophy, the effect of YH529, a third generation bisphosphonate, was studied on hind limb atrophy in rats subjected to tail suspension. YH529 (YH group) or PBS (control group) were administered subcutaneously in 5-week-old male Wistar rats suspended for 7 days. In the control group, wet weight, calcium and phosphorus contents decreased significantly in the femur but they did not change in the humerus. In the YH group, however, these parameters did not change significantly in the femur, but both calcium and phosphorus increased significantly in the humerus. These results indicate that the inhibition of bone resorption by YH529 prevents the development of disuse atrophy induced by tail suspension. It is thus suggested that early increases in bone resorption are important for the development of disuse bone atrophy.

Terrestrial applications of bone and muscle research in microgravity

Major applications to people on Earth are possible from NASA-sponsored research on bone and muscle which is conducted either in microgravity or on Earth using models mimicking microgravity. In microgravity bone and muscle mass are lost. Humans experience a similar loss under certain conditions on Earth. Bone and muscle loss exist on Earth as humans age from adulthood to senescence, during limb immobilization for healing of orthopedic injuries, during wheelchair confinement because of certain diseases, and during chronic bed rest prescribed for curing of diseases. NASA-sponsored research is dedicated to learning both what cause bone and muscle loss as well as finding out how to prevent this loss. The health ramifications of these discoveries will have major impact. Objective 1.6 of Healthy People 2000, a report from the U.S. Department of Health and Human Services, states that the performance of physical activities that improve muscular strength, muscular endurance, and flexibility is particularly important to maintaining functional independence and social integration in older adults. This objective further states that these types of physical activities are important because they may protect against disability, an event which costs the U.S. economy huge sums of money. Thus NASA research related to bone and muscle loss has potential major impact on the quality of life in the U.S. Relative to its potential health benefits, NASA and Congressional support of bone and muscle research is funded at a very low level.

Prevention of space flight induced soft tissue calcification and disuse osteoporosis

This paper emphasizes the devastating effects of displacement of calcium during space flight, due to increased bone turnover.

Countermeasures against space flight related bone loss

This paper reviews human data concerning bone loss and attempted countermeasures during spaceflight and bed rest, a commonly employed technique to simulate the effects of weightlessness on the musculoskeletal system.

Prevention of bone loss and muscle atrophy during manned space flight

This paper reviews the biomedical literature concerning human adaptation to nonterrestrial environments, and focuses on the definition of practical countermeasures necessary for long-term survival on the Moon, Mars and during long-term space missions and exploration. Of particular importance is the development of clinically relevant countermeasures for prevention of pathophysiological changes in the musculoskeletal and cardiopulmonary systems under these conditions. The countermeasures which are proposed are based upon a combination of biomechanical and theoretical analyses. The biomechanical analyses are based upon clinical measurements of human skeletal density changes associated with weight lifting as well as clinical studies of human strength and fitness currently being conducted using an isoinertial trunk dynamometer. The theoretical analysis stems from a mathematical model for bone loss in altered gravity environments that we have begun to develop. These analyses provide guidelines for the development of practical therapeutic treatments (exercise, artificial gravity) designed to minimize musculoskeletal deconditioning associated with less than Earth gravity environments. Our findings suggest that very intensive exercise, which impose high loads on the musculoskeletal system for brief periods, may be more efficient in preserving bone and skeletal muscle conditioning within "safe" limits for longer periods than low intensity activities such as treadmill running and bicycling. A 1/6 to 1/7-g gravitational environment is predicted to be sufficient to preserve bone strength above the fracture risk level. Basic biomedical support of manned space missions, Moon and Mars bases should include routine assessment of skeletal density, muscle strength, cardiac output and total energy expenditure. This information can be used to periodically re-evaluate exercise programs and or artificial gravity requirements for crew members.

Combined injury syndrome in space-related radiation environments

The risk of combined injury (CI) to space travelers is a function of exposure to anomalously large surges of a broad spectrum of particulate and photon radiations, conventional trauma (T), and effects of weightlessness including decreased intravascular fluid volume, and myocardial deconditioning. CI may occur even at relatively low doses of radiation which can synergistically enhance morbidity and mortality from T. Without effective countermeasures, prolonged residence in space is expected to predispose most individuals to bone fractures as a result of calcium loss in the microgravity environment. Immune dysfunction may occur from residence in space independent of radiation exposure. Thus, wound healing would be compromised if infection were to occur. Survival of the space traveler with CI would be significantly compromised if there were delays in wound closure or in the application of simple supportive medical or surgical therapies. Particulate radiation has the potential for causing greater gastrointestinal injury than photon radiation, but bone healing should not be compromised at the expected doses of either type of radiation in space.