Influence of high and low protein intakes on age-related bone loss in rats submitted to adequate or restricted energy conditions

Low energy and protein intake has been suggested to contribute to the increased incidence of osteoporosis in the elderly. The impact of dietary protein on bone health is still a matter of debate. Therefore, we examined the effect of the modulation of protein intake under adequate or deficient energy conditions on bone status in 16-month-old male rats. The animals were randomly allocated to six groups (n = 10/group). Control animals were fed a diet providing either a normal-protein content (13%, C-NP) or a high-protein content (26%) (C-HP). The other groups received a 40% protein/energy-restricted diet (PER-NP and PER-HP) or a normal protein/energy-restricted diet (ER-NP and ER-HP). After 5 months of the experiment, protein intake (13% or 26%) did not modulate calcium retention or bone status in those rats, although a low-grade metabolic acidosis was induced with the HP diet. Both restrictions (PER and ER) decreased femoral bone mineral density and fracture load. Plasma osteocalcin and urinary deoxypyridinoline levels were lowered, suggesting a decrease in bone turnover in the PER and ER groups. Circulating insulin-like growth factor-I levels were also lowered by dietary restrictions, together with calcium retention. Adequate protein intake in the ER condition did not elicit any bone-sparing effect compared to PER rats. In conclusion, both energy and protein deficiencies may contribute to age-related bone loss. This study highlights the importance of sustaining adequate energy and protein provision to preserve skeletal integrity in the elderly.

Long-term intake of a high-protein diet with or without potassium citrate modulates acid-base metabolism, but not bone status, in male rats

High dietary protein intake generates endogenous acid production, which may adversely affect bone health. Alkaline potassium citrate (Kcit)(2) may contribute to the neutralization of the protein-induced metabolic acidosis. We investigated the impact of 2 levels of protein intake and Kcit supplementation on acid-base metabolism and bone status in rats. Two-month-old Wistar male rats were randomly assigned to 4 groups (n = 30 per group). Two groups received a normal-protein content (13%) (NP) or a high-protein (HP) content diet (26%) for 19 mo. The 2 other groups received identical diets supplemented with Kcit (3.60%) (NPKcit and HPKcit). Rats were pair-fed based on the ad libitum intake of the HP group. At 9, 16, and 21 mo of age, 10 rats of each group were killed. The HP diet induced a metabolic acidosis characterized by hypercalciuria, hypermagnesuria, and hypocitraturia at all ages. Kcit supplementation neutralized this effect, as evidenced by decreased urinary calcium and magnesium excretion by the HPKcit rats. Femoral bone mineral density, biomechanical properties, bone metabolism biomarkers (osteocalcin and deoxypyridinoline), and plasma insulin-like growth factor 1 levels were not affected by the different diets. Nevertheless, at 21 mo of age, calcium retention was reduced in the HP group. This study suggests that lifelong excess of dietary protein results in low-grade metabolic acidosis without affecting the skeleton, which may be protected by an adequate calcium supply.

Influence of lifelong soy isoflavones consumption on bone mass in the rat

Soy isoflavones (IFs) have shown a bone-sparing effect through epidemiological studies in the Asian population. However, there is no evidence as to whether such protection would result from a lifelong exposure. We investigated the impact of an early exposure to IFs on bone status. Sixty female Wistar rats were fed either a standard diet (n=30) or the same food enriched with IFs (0.87 mg/g of diet) (n=30). After 1 month, they were allowed to mate, and were kept on the same regimen during the whole gestation and lactation periods. At weaning, female pups were each assigned to one of four nutritional groups; within each experimental group, animals were split into two groups, fed either the standard or the IF-rich diet. At 2, 3, 6, 12, 18, and 24 months after birth, 10 animals in each group were sacrificed. Femurs were collected for mechanical testing and bone mineral density (BMD) measurement. The rats perinatally or lifelong exposed to the IF-rich diet exhibited higher body weight and fat mass at 24 months of age. Peak bone mass was achieved between 6 and 12 months and did not differ between groups. In animals perinatally exposed to IF, BMD continued to increase. Thus, at 24 months, femoral total BMD (P<0.05), metaphyseal BMD (P<0.01), and failure load (P<0.05) were higher in the offspring born from mothers provided IF during pregnancy. Postnatal exposure alone did not improve bone parameters. This experiment provides evidence that perinatal exposure to phytoestrogens leads to a higher BMD later in life. It is suggested that these changes may have occurred as a consequence of programming effects, as has been shown for the endocrine and immune systems.

Hesperidin inhibits ovariectomized-induced osteopenia and shows differential effects on bone mass and strength in young and adult intact rats

The main aim of this study was to investigate the bone-sparing effect of hesperidin, one of the main flavonoid present in oranges, in two age groups of ovariectomized female rats, compared with their intact controls. Young (3 mo) and adult (6 mo) female Wistar rats were sham operated (SH) or ovariectomized (OVX) and then pair-fed for 90 days a casein-based diet supplemented or not with 0.5% hesperidin (Hp; n = 10/group). In older rats, Hp intake led to a partial inhibition of OVX-induced bone loss, whereas a complete inhibition was obtained in younger animals. At both ages, while plasma osteocalcin concentrations were unchanged, urinary excretion of deoxypyridinoline was reduced by Hp intake, suggesting that Hp was able to slow down bone resorption. Unexpectedly, in intact young rats, Hp consumption resulted in a significant increase in bone mineral density (BMD). Indeed, 6-mo-old HpSH rats had a similar BMD to 9-mo-old nontreated SH adult rats, suggesting an accelerated bone mass gain in the young rats. In contrast, in intact adult rats, Hp did not further increase BMD but did improve their bone strength. The results of this study show a protective effect of Hp on bone loss in OVX rats of both ages without uterine stimulation and accompanied by a lipid-lowering effect. The unexpected and intriguing findings obtained in intact rats showing improved BMD in young rats and improved femoral load in adult rats merit further investigation. The bone and lipid benefits of hesperidin make it an attractive dietary agent for the management of the health of postmenopausal women.

Effects of isometric strength training followed by no exercise and Humulus lupulus L-enriched diet on bone metabolism in old female rats

We investigated in female rats the effects on bone metabolism of a prolonged no-training period, subsequent to an isometric exercise program, performed during young adulthood and those of a long-term consumption of Humulus lupulus L-enriched diet (genistein 1.92 and daidzein 1.24 mg/kg diet) combined or not with isometric training. Forty-eight rats (4 weeks old) were randomly divided into 4 groups: trained (C-Tr) or nontrained rats (C-NTr) fed with control diet and trained (H-Tr) or nontrained rats (H-NTr) fed with Humulus lupulus L-enriched diet. The diets lasted 100 weeks. Training was followed over a 25-week period. Bone parameters were measured at week 100. Our results showed that no significant difference was observed among the 4 groups in uterine relative weight, calcium (Ca) intake, fecal Ca, urinary Ca excretion, net Ca absorption, plasma Ca, and bone Ca content. Calcium balance was significantly enhanced in H-NTr rats in comparison with C-NTr and C-Tr rats. Isometric strength training led to a significant increase in total bone mineral density (BMD), diaphyseal BMD, and osteocalcin-deoxypyridinoline ratio in C-Tr rats compared with the other groups. The main findings of the present study indicate that in female rats, a 25-week isometric strength training performed during young adulthood followed by a prolonged no-training period increases BMD values and osteocalcin-deoxypyridinoline ratio, whereas long-term consumption of Humulus lupulus L-enriched diet does not improve bone parameters. It suggests that bone gains induced by exercise do not decrease immediately after cessation of training and also confirms the importance of the practice of physical activity during puberty and young adulthood to maximize the achieved peak bone density.

Black Lucques olives prevented bone loss caused by ovariectomy and talc granulomatosis in rats

This study was conducted to determine whether olive fruits, rich in micronutrients, might improve bone loss in ovariectomized (OVX) rats (an experimental model of postmenopausal osteoporosis) and in OVX rats with granulomatosis inflammation (a model of senile osteoporosis). Six-month-old Wistar female rats underwent ovariectomy and were then immediately treated orally by substituting oil in the diet by 10 g/d green Lucques olives or 6 g/d black Lucques olives for each rat for 84 days. OVX rats and sham-operated controls received the same diet with oil. Three weeks before the end of the experiment, subcutaneous inflammation was provoked by injections of sterile magnesium silicate in half the animals in each group. In OVX rats, granulomatosis inflammation, characterized by a rise in inflammatory parameters such as fibrinogen, alpha1-acid glycoprotein, spleen weight and granulocyte level, and an impairment of oxidative status (as shown by a decrease in plasma antioxidant capacity, a higher rate of isoprostane excretion) elicited a bone loss in the whole femur and in the metaphyseal areas considered on their own. Whereas green olives had no effect on osteopenia, consumption of the black variety prevented bone loss in the whole femur and at cortical sites in those oestrogen-deficient animals with talc inflammation (diaphyseal bone mineral density: black olives and inflammation 0-2323 (SE 0.0026) v. ovariectomy and inflammation 0.2117 (SE 0.0030); P=0.027). This bone-sparing effect seemed to result from an improvement in the inflammatory and oxidative status. The present data show that black olives are able to prevent bone loss in an experimental model of senile osteoporosis (oestrogen-deficient rats in which a low-grade inflammation was induced by talc injection).

A specific database for providing local and national level of integration of clinical data in cystic fibrosis

It has recently been stated that a database is an essential tool in the management of CF. The purpose of this work is to create a specific database allowing optimal performance of storage, search and retrieval functions on patients with CF. A specific database was developed using a Windev licence, for application via Microsoft supported platforms or Intranet system. The database allows real-time point of care data management of medical, investigational and administrative data. It is currently being used in the 6 Belgian reference centres. It represents a useful tool for gathering information on routine clinical and lab data, bacteriology, treatments, complications and specific outcomes for clinical and research purposes. The ongoing evolution of the database includes enhancements toward research data orientation including comparison of patient data between different centres and completeness of the National CF registry questionnaire. A complimentary copy of the software can be provided to multidisciplinary accredited CF centres worldwide upon request.

Modulation of soy isoflavones bioavailability and subsequent effects on bone health in ovariectomized rats: the case for equol

INTRODUCTION

Soy products are of particular interest because of their potential health benefits in a range of hormonal conditions, such as osteoporosis, due to their high content in phytoestrogens. Because equol, the main metabolite from soy isoflavones, is thought to be powerful, the present study was designated to evaluate the bone-sparing effects of equol by either providing the molecule through the diet or by eliciting its endogenous production by modulating intestinal microflora by short-chain fructooligosaccharides (sc-FOS) or live microbial (Lactobacillus casei) together with daidzein, its precursor.

METHODS

A comparison with daidzein and genistein was also performed. Rats (3 months old) were ovariectomised (OVX) or sham-operated (SH). Ovariectomised rats were randomly assigned to six experimental diets for 3 months: a control diet (OVX), the control diet supplemented with either genistein (G), or daidzein (D), or equol (E) at the level of 10 microg/g body weight/d. The remaining OVX rats were given daidzein at the dose of 10 mug/g body weight/d, simultaneously with short-chain FOS (Actilight, Beghin-Meiji) (D+FOS) or Lactobacillus casei (Actimel, Danone) (D+L). The SH rats were given the same control diet as OVX.

RESULTS

Genistein, daidzein or equol exhibited a bone sparing effect. Indeed, total femoral bone mineral density (BMD) was significantly enhanced (compared to that of OVX rats), as was the metaphyseal compartment. Bone strength was improved by E consumption, but not by genistein or daidzein given alone. As far as the FOS diet is concerned, the addition of prebiotics significantly raised efficiency of the daidzein protective effect on both femoral BMD and mechanical properties. The effects of lactobacillus were similar, except that the increase in metaphyseal-BMD was not significant.

CONCLUSION

In conclusion, long-term equol consumption, like genistein and daidzein, in the ovariectomized rat, provides bone sparing effects. Adding indigestible sugars, such as FOS or live microbial as L. casei, in the diet significantly improves daidzein protective effects on the skeleton.

Pseudomonas aeruginosa: resistance and therapeutic options at the turn of the new millennium

Pseudomonas aeruginosa is a major cause of nosocomial infections. This organism shows a remarkable capacity to resist antibiotics, either intrinsically (because of constitutive expression of beta-lactamases and efflux pumps, combined with low permeability of the outer-membrane) or following acquisition of resistance genes (e.g., genes for beta-lactamases, or enzymes inactivating aminoglycosides or modifying their target), over-expression of efflux pumps, decreased expression of porins, or mutations in quinolone targets. Worryingly, these mechanisms are often present simultaneously, thereby conferring multiresistant phenotypes. Susceptibility testing is therefore crucial in clinical practice. Empirical treatment usually involves combination therapy, selected on the basis of known local epidemiology (usually a beta-lactam plus an aminoglycoside or a fluoroquinolone). However, therapy should be simplified as soon as possible, based on susceptibility data and the patient's clinical evolution. Alternative drugs (e.g., colistin) have proven useful against multiresistant strains, but innovative therapeutic options for the future remain scarce, while attempts to develop vaccines have been unsuccessful to date. Among broad-spectrum antibiotics in development, ceftobiprole, sitafloxacin and doripenem show interesting in-vitro activity, although the first two molecules have been evaluated in clinics only against Gram-positive organisms. Doripenem has received a fast track designation from the US Food and Drug Administration for the treatment of nosocomial pneumonia. Pump inhibitors are undergoing phase I trials in cystic fibrosis patients. Therefore, selecting appropriate antibiotics and optimising their use on the basis of pharmacodynamic concepts currently remains the best way of coping with pseudomonal infections.

[Cystic fibrosis and pseudomonas aeruginosa current and future strategies]

Cystic fibrosis and Pseudomonas aeruginosa current and future strategies Pseudomonas aeruginosa is long recognized as the main pathogen in cystic fibrosis and avoiding or postponing chronic colonization of the lungs by this germ is considered as the most important challenge for the clinicians dedicated to the care of CF patient. The need for early intervention is widely accepted but its optimal modalities are still debated and the failure rate of this approach is estimated around 20%. This underlines the potential of other strategies including attempts to develop an effective vaccine against PA and anti-PA prophylaxis. Surprisingly enough, the latter approach which could involve early use of inhaled antibiotics has never been studied prospectively. In chronically colonized patients, inhaled antibiotics and oral azythromycin are of value, slowing the FEV1 decline and reducing the number of exacerbations. Whether intravenous antibiotics are to be used electively (during exacerbations) or more systematically (every 3 months for example) remains controversial.

[Etology and treatment of community acquired pneumonia in children]

In children under 5 years, most lower respiratory tract infections are caused by viruses and do not require antibiotics. This is true for almost all episodes of bronchitis and bronchiolitis but also for the majority of pneumonias. Atypical pneumonias due to Mycoplasma pneumoniae or Chlamydia pneumoniae predominate in older children while Streptococcus pneumoniae remains by far the most common cause of bacterial pneumonia. Diagnosis of pneumonia itself can be difficult and relies on a combination of clinical judgement and radiological and laboratory investigations. In real-life situations, etiologic agents are rarely identified, an issue further complicated by the possibility of mixed infections particularly in hospitalised children. Since viruses are often the sole cause of pneumonia in childhood, it is appropriate not to treat every child with antibiotics. However, when a bacterial origin can not be excluded, antibiotics efficient on Streptococcus pneumoniae are to be prescribed. Amoxicillin is the first choice empirical antibiotic treatment, having a higher efficacy on poorly sensitive pneumococcus than cephalosporins. Macrolides are indicated for the treatment of atypical pneumonia. Current immunisation strategies have decreased the number of bacterial pneumonias. However, there is some evidence that among hospitalised children the rate of complicated pneumonias is increasing with an emerging role of Streptococcus pneumoniae serotype 1, which is not covered in the 7-valent vaccine.

Mucoviscidose : le kinésithérapeute face au risque infectieux

INTRODUCTION

Respiratory infections play a deleterious role in the progression of patients suffering from cystic fibrosis. Cross infections and epidemics have been documented in these patients, justifying a rigorous prevention regime.

BACKGROUND

This prevention regime concerns all health workers and rests on various recommendations. Segregation of patients and hand hygiene are important factors. Respiratory equipment and, more specifically, nebulisers represent a potential source of bacterial contamination requiring special attention. In the same perspective the risks related to the health care environment, particularly the lung function laboratory, should not be ignored. The modalities of prevention sometimes have a significant psychological impact that may often be reduced by careful explanation.

CONCLUSIONS

In view of the time spent in contact with these patients the physiotherapists are naturally involved in this prevention regime which is an integral part of their treatment.

Alterations in glutamine synthetase activity in rat skeletal muscle are associated with advanced age

OBJECTIVE

Glutamine synthetase (GS), a key enzyme in the production of glutamine, is preserved in skeletal muscle during early aging (<24 mo). Because the effects of advanced age on GS are unknown, we investigated the effect of advanced age (>24 mo) on GS activity in skeletal muscle. We hypothesized that advanced age would enhance muscle GS activity.

METHODS

Muscle GS activities were assessed in adult (8 mo), mature adult (15 mo), aged (20-22 mo), advanced age (25-27 mo), or very advanced age (29-32 mo) female Wistar rats. Male Wistar (6-27 mo) were used to investigate the effect of gender on this activity.

RESULTS

Glutamine synthetase activity remained low and unaltered in rats from 8 to 22 mo of age, as previously demonstrated. In contrast, GS activity was high ( approximately 75% of individual values were higher than the low value mean) in 25-mo to 27-mo-old rats. In very-old-aged rats (29-32 mo), approximately 55% of GS activity data points exhibited low values. Changes in GS protein content paralleled those in GS activities. In male rats, GS activity was also high ( approximately 80% of individual values were higher than the mean value of 6-mo to 19-mo-old rats) at the upper limit of life expectancy (27 mo).

CONCLUSION

There is enhanced GS activity in old female and male rats suggesting a greater need for glutamine. In some very old rats, low GS activity may be associated with longevity or reflect a limitation in glutamine production due to extremely advanced age per se.

Survey of Pseudomonas aeruginosa genotypes in colonised cystic fibrosis patients

The current authors aimed to examine whether cystic fibrosis (CF) patients in Belgium shared Pseudomonas aeruginosa genotypes and to compare the genotypes of isolates from the same patients during two consecutive years. A Belgian databank of the P. aeruginosa genotypes of all colonised CF patients was created. Sputum samples from a total of 276 P. aeruginosa colonised patients during 2003, and from a subgroup of 95 patients in 2004, were analysed. Patients were asked about any social contact between each other by questionnaire. All P. aeruginosa isolates exhibiting different colonial morphology on McConkey agar were first genotyped using arbitrarily primed PCR, whereafter single representatives of each randomly amplified polymorphic DNA-type were further genotyped by fluorescent amplified fragment length polymorphism analysis. In the 213 patients from whom P. aeruginosa could be cultured (resulting in 910 isolates), a total of 163 genotypes were found. The majority (75%) of patients harboured only one genotype. In most of the limited number of clusters, previous contacts between patients could be suspected. In 80% of the patients studied during both years, P. aeruginosa genotype remained unchanged. In conclusion, most colonised cystic fibrosis patients harbour only one Pseudomonas aeruginosa genotype, despite showing different colonial morphotypes. The number of clusters is limited, and most patients seem to retain the same genotypic strain during both years.

Dose-response study of effect of oleuropein, an olive oil polyphenol, in an ovariectomy/inflammation experimental model of bone loss in the rat

BACKGROUND & AIMS

This study was carried out to assess the dose-dependent bone-sparing effect of oleuropein, an olive oil phenolic compound with anti-inflammatory and anti-oxidative properties, on bone loss induced by talc granulomatosis in oestrogen-deficient rat.

METHODS

Among 98 rats, 20 were sham-operated (SH) while the others (78) were ovariectomised (OVX). The SH and 26 OVX rats (controls) were given a standard diet for 100 days. The 52 remaining OVX rats were allocated to 4 groups that received oleuropein at 2.5, 5, 10 or 15 mg/kg body weight per day for 100 days. Three weeks before necropsy, an inflammation was induced by subcutaneous injections of talc in half of the SH and OVX rats and in all oleuropein-treated animals.

RESULTS

Castration was associated with a decreased bone mineral density (BMD). In OVX rats, inflammation, characterised by an increase of the spleen weight and plasma fibrinogen levels, exacerbated this bone loss, as shown by values of BMD of the total femur metaphyseal and diaphyseal subregions. The 4 doses of oleuropein reduced bone loss and improved inflammatory biomarkers excepted for 5mg/kg BW.

CONCLUSIONS

Every dose of oleuropein elicited protective effects on bone mass in this model of ovariectomy associated with inflammation, probably by modulating inflammatory parameters.

Prevention of bone loss by phloridzin, an apple polyphenol, in ovariectomized rats under inflammation conditions

Aging and sex hormones related changes lead to inflammatory and oxidant conditions, which are involved in the pathogenesis of osteoporosis. Recent studies have suggested that polyphenols may exert a protective effect in such conditions. We assessed the effect of phloridzin (Phlo), a flavonoid exclusively found in apple, on bone metabolism in ovariectomized (OVX) or sham-operated (SH) rats with and without inflammation. Six-month-old Wistar rats were allocated to two equal groups that received either a control diet or a diet supplemented with 0.25% Phlo for 80 days. Three weeks before necropsy, inflammation was induced by subcutaneous injection of talc in 10 animals of each group. At necropsy, ovariectomy decreased both total (T-BMD) and metaphyseal (M-BMD) femoral bone mineral density (P < 0.01). Inflammation conditions, checked by an increase in the spleen weight and alpha1-acid glycoprotein concentration in OVX rats, exacerbated the decrease in T-BMD (g/cm2) (as well as M-BMD) observed in castrated animals (P < 0.05). Daily Phlo intake prevented ovariectomy-induced bone loss in conditions of inflammation as shown by T-BMD and M-BMD (P < 0.05). At the diaphyseal site, BMD was improved by Phlo in OVX rats with or without inflammation (P < 0.05). These results could be explained by changes in bone remodeling as the increased urinary deoxypyridinoline excretion in OVX and OVXinf animals was prevented by the polyphenol-rich diet (P < 0.001), while plasma osteocalcin concentration was similar in all experimental groups. In conclusion, Phlo consumption may provide protection against ovariectomy-induced osteopenia under inflammation conditions by improving inflammation markers and bone resorption.

In vitro evaluation of efficacy of 5 methods of disinfection on mouthpieces and facemasks contaminated by strains of cystic fibrosis patients

INTRODUCTION

Home-nebulizers are a potential source of bacterial infection of the respiratory tract in patients suffering from cystic fibrosis. Recommendations for disinfecting this equipment are often arbitrary and sometimes contradictory.

OBJECTIVE

To assess in vitro the effectiveness of 5 methods of disinfecting this equipment.

METHODS

160 mouthpieces and 160 masks of nebulizers were artificially and massively contaminated with 16 strains of germs found in patients with cystic fibrosis (Staphylococcus aureus, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Burkholderia cenocepacia, Alcaligenes xylosoxydans). A controlled comparison was carried out of the five methods of disinfection (hypochlorite solution (0.02% active chlorine), acetic acid 3.5%, Hexanios 0.5%, washing-up detergent 0.5% and a dishwasher), tested with and without drying. Standardised bacteriological sampling took place 4 h after disinfecting.

RESULTS

Following treatment, the disappearance of the germ was recorded in 84.1% of cases, and effective disinfecting (reduction>5 log CFU/mL) in another 10.6%. Disinfection failure (5.3%) was found almost only in the case of acetic acid against Staphylococcus aureus.

CONCLUSION

With the exception of acetic acid, the methods of disinfecting tested in this study appeared to be effective against common bacterial pathogens in cystic fibrosis.

Preventive effect of Abelmoschus manihot (L.) Medik. on bone loss in the ovariectomised rats

Because the biggest culprit in pathogenesis of osteoporosis is oestrogen deficiency, hormone replacement therapy remained the mainstay for prevention. However most of postmenopausal women are more inclined to use natural alternative. We thus investigated the ability of Abelmoschus manihot, a herbal medicine to prevent bone loss in ovariectomised rats. Female Wistar rats were sham operated (SH: 8) or ovariectomised (OVX: 24). On day 0, OVX rats were randomly assigned to groups as follows: eight received 10% Abelmoschus manihot leaves in their diet, eight were given 15% Abelmoschus manihot leaves and eight were untreated (OVX). Compounds were mixed with a soy protein-free diet and given orally for 3 months. At necropsy, bone mineral density (BMD) in the femur and in its metaphyseal zone was lower in OVX than SH (p<0.05). This osteopenia was prevented by consumption of the highest dose of Abelmoschus manihot leaves. Bone mineral content (BMC) in the total femur and its metaphyseal and diaphyseal subregions was improved, as well (p<0.05). This could be explained by a trend towards decreased bone resorption. The lowest dose did not elicit any significant effect. In conclusion, Abelmoschus manihot consumption, at the dose of 15% in the diet, provided bone-sparing effects by improving both BMD and BMC.

Third metacarpal bone mineral density assessment in the standing horse by dual X-ray absorptiometry: suitability, precision and accuracy

Bone mineral density (BMD) is correlated to mechanical properties of bone. In the horse, dual energy X-ray absorptiometry (DXA) has yet only been performed ex-vivo, but a new portable DXA device would be ideal for in-vivo BMD measurement. We explored field suitability, precision and accuracy of this device for in-vivo third metacarpal density assessment. Precision was analysed by calculating measurement variation under repeated measurement tests with (reproducibility) and without (repeatability) limb repositioning. Repeatability and reproducibility were tested ex-vivo, at the same time that intra- and inter-operator reproducibility were assessed in-vivo. In order to test accuracy, bone mineral content (BMC) of several bone samples determined by DXA and ashing were compared. Repeatability was 1.47% and reproducibility 1.69% ex-vivo. In-vivo reproducibility varied between 2.91 and 4.06% for intra-operator test and between 3.13 and 5.53% for inter-operator test. BMC measured by DXA and ash weight were highly correlated (R2>0.99). In conclusion, under described conditions this DXA device is usable, accurate and precise. Its sensitiveness reaches 8.23% in an individual longitudinal monitoring. Using the third metacarpal bone as an example, we have shown that this device is suitable for experimental or clinical monitoring.

Fructooligosaccharides maximize bone-sparing effects of soy isoflavone-enriched diet in the ovariectomized rat

Isoflavones (IF) have been increasingly implicated for use in the prevention of osteoporosis. As their bioavailability could be improved by modulating intestinal microflora, the present study was undertaken to investigate whether IF and fructooligosaccharides (FOS), which are known to modify large-bowel flora and metabolism, may exhibit a cooperative bone-sparing effect. This work was carried out on 3-month-old Wistar rats assigned to 12 groups: 2 SH (sham-operated) and 10 OVX (ovariectomized). Animals received a diet for 90 days containing total IF (Prevastei HC, Central Soya) at 0 (OVX and SH), 10 (IF10), 20 (IF20), 40 (IF40), or 80 (IF80) microg/g body weight per day. FOS (Actilight, Beghin-Meiji) were orally given to half of the groups, (OVX FOS), (IF10 FOS), (IF20 FOS), (IF40 FOS), (IF80 FOS), and (SH FOS). Isoflavones exhibited a bone-sparing effect as soon as consumption reached 20 microg/g/day, whereas only the highest dose induced a weak uterotrophic activity. Indeed, total femoral bone mineral density (BMD) was significantly enhanced (compared with that of OVX rats), as was the metaphyseal compartment. Bone strength was improved as well. As far as the FOS diet is concerned, addition of prebiotics significantly raised the efficiency of the IF protective effect on both femoral BMD and mechanical properties. The trend toward higher BMD levels with the lowest IF dose (IF10) even reached a significant level when FOS were added. This effect could be explained by a reduced bone resorption. In conclusion, daily IF consumption prevented castration-induced osteopenia by decreasing bone resorption when given at 20, 40, or 80 microg (total isoflavones)/g/day. Simultaneous FOS consumption improved IF protective effect on the skeleton, with the lowest IF dose becoming efficient. Enhancement of IF bioavailability, following FOS fermentation, is probably involved.

Olive oil and its main phenolic micronutrient (oleuropein) prevent inflammation-induced bone loss in the ovariectomised rat

The present study was designed to evaluate the effect of olive oil and its main polyphenol (oleuropein) in ovariectomised rats with or without inflammation. Rats (6 months old) were ovariectomised or sham-operated as control. Ovariectomised rats were separated into three groups receiving different diets for 3 months: a control diet with 25 g peanut oil and 25 g rapeseed oil/kg (OVX), the control diet with 50 g olive oil/kg or the control diet with 0.15 g oleuropein/kg. The sham-operated group was given the same control diet as OVX. Inflammation was induced 3 weeks before the end of the experiment by subcutaneous injections of talc (magnesium silicate) in one-half of each group. The success of ovariectomy was verified at necropsy by the atrophy of uterine horns. Inflammation, oleuropein or olive oil intakes did not have any uterotrophic activity, as they had had no effect on uterus weight. The plasma concentration of alpha-1-acid glycoprotein (an indicator of inflammation) was increased in OVX rats with inflammation. With regard to bone variables, osteopenia in OVX was exacerbated by inflammation, as shown by a decrease in metaphyseal and total femoral mineral density. Both oleuropein and olive oil prevented this bone loss in OVX rats with inflammation. At necropsy, oleuropein and olive oil consumption had had no effect on plasma osteocalcin concentrations (marker of bone formation) or on urinary deoxypyridinoline excretion (marker of bone resorption). In conclusion, oleuropein and olive-oil feeding can prevent inflammation-induced osteopenia in OVX rats.