Pseudo-polyarthrite rhizomélique et artérite à cellules géantes dans les suites d’une vaccination contre la Covid-19 : à propos de 5 cas

Introduction

Observation

Discussion

Conclusion

The French multicentre elevated bone mass study: prevalence and causes

The purpose of this multicentric study was to evaluate the prevalence and causes of Elevated Bone Mass (EBM) in patients who underwent DXA scanning over a 10-year period. The prevalence of EBM was 1 in 100. The main causes of EBM were degenerative spine disorders and renal osteodystrophy.

INTRODUCTION

Reports of elevated bone mass (EBM) on routine dual energy X-Ray absorptiometry (DXA) scanning are not infrequent. However, epidemiological studies of EBM are few and definition thresholds are variable. The purpose of this French multicentric study was to evaluate the prevalence and causes of EBM in adult patients who underwent DXA scanning over a 10-year period.

METHODS

This multicentric, retrospective study was conducted in six French regional bone centres. DXA databases were initially searched for individuals with a bone mineral density (BMD) Z-score ≥ +4 at any site in the lumbar spine or hip from April 1st, 2008 to April 30st, 2018.

RESULTS

In all, 72,225 patients with at least one DXA scan were identified. Of these, 909 (322 men and 587 women) had a Z-score ≥ + 4, i.e. a prevalence of 1.26% [1.18-1.34%]. The DXA scan reports and imagery and medical records of the 909 EBM patients were reviewed and 936 causes were found. In 42 patients (4%), no cause could be determined due to unavailability of data. Artefactual causes of EBM were found in 752 patients (80%), in whom the predominant cause was degenerative disease of the spine (613 patients, 65%). Acquired causes of focal EBM-including Paget's disease (n = 7)-were found in 12 patients (1%), and acquired causes of generalized EBM-including renal osteodystrophy (n = 32), haematological disorders (n = 20) and hypoparathyroidism (n = 15)-in 84 patients (9%). Other causes were rare hereditary diseases and unknown EBM in 19 (2%) and 27 (3%) cases respectively.

CONCLUSIONS

The prevalence of EBM was approximately 1 in 100. These findings suggest that degenerative disease of the spine is the main cause of EBM, but that acquired or hereditary diseases are also causal factors.

Etiology of avascular osteonecrosis of the femoral head

Avascular osteonecrosis of the femoral head (ONFH) is one of the causes of hip pain that clinicians need to know about. In many cases, it is a fortuitous discovery when pelvic X-rays is performed for another reason. In the other cases, pain reveals the disease. For the rheumatologist, a major part of the job is to look for a cause. An etiology can be found to ONFH in about 70% of the cases. Some of them are evident and the context give the diagnosis (corticosteroids, alcohol abuse…). However, in many cases, additional tests to imaging are required to make the causal diagnosis. In some cases, the treatment of the cause can prevent the recurrence of the disease.

Methotrexate osteopathy: five cases and systematic literature review

INTRODUCTION

Methotrexate (MTX)-related osteopathy is rare, defined by the triad of pain, osteoporosis, and "atypical fractures" when it was first described in the 1970s in children treated with high doses MTX for acute leukemia. Since then, several cases have been reported in patients treated with low-dose MTX for inflammatory diseases.

METHODS

A systematic research of cases of MTX-related osteopathy was performed in records of Rheumatology Department of Rennes University Hospital. Data collection focused on demographic data, corticosteroid doses, MTX doses and intake method, cumulative doses, year of diagnosis, fracture location, bone densitometry value, and osteoporosis treatment if necessary. A literature review was also conducted to identify other cases in literature and try to understand the pathophysiological mechanisms of this rare entity.

RESULTS

We report 5 cases identified between 2011 and 2019, which represents the largest cohort described excluding oncology cases. Fracture locations were atypical for osteoporotic fractures. All patients improved in the following months with MTX withdrawal. All patients except one were treated with antiresorptives (bisphosphonates, denosumab). Two patients, treated with bisphosphonates, had a recurrence of fracture, once again of atypical location. Twenty-five cases were collected in literature with similar clinical presentation. The cellular studies that investigated the bone toxicity of MTX mainly showed a decrease in the number of osteoblasts, osteocytes, and chondrocytes in the growth plate and an increase in the number and activity of osteoclasts. In vitro, consequences of mechanical stimulation on human trabecular bone cells in the presence of MTX showed an alteration in mechano-transduction, with membrane hyperpolarization, acting on the integrin pathway. In contrast with our report, the cases described in the literature were not consistently associated with a decrease in bone mineral density (BMD).

CONCLUSION

MTX osteopathy while rare must be known by the rheumatologist, especially when using this treatment for inflammatory conditions. The mechanisms are still poorly understood, raising the question of a possible remnant effect of MTX on osteo-forming bone cells, potentially dose-dependent. Methotrexate (MTX) osteopathy, described as a clinical triad, pain, osteoporosis, and atypical stress fractures, while rare, must be known by the rheumatologist. Our cohort of 5 cases represent the largest series of the literature. Pathophysiological studies raised the question of a dose-dependent remnant effect of MTX on osteo-forming bone cells.

External validation of Gout-calculator performance on a cohort of acute arthritis (SYNOLACTATE) sparing distal joints such as hallux and midfoot. A cross-sectional study of 170 patients

OBJECTIVE

To evaluate the performance of the Gout-calculator in a cohort of consecutive acute arthritis affecting large and intermediate joints (without an attack on hallux or midfoot joints).

METHODS

A retrospective study. Gout-calculator data were collected in medical records of patients included in the prospective consecutive cohort of acute arthritis called SYNOLACTATE. The diagnosis of gout was defined by the presence of sodium urate crystals in synovial fluid. The diagnostic performance of the Gout-calculator was studied by performing an ROC curve with the calculation of its AUC (95% CI) as well as the calculation of Sensitivity (Se), Specificity (Sp), and positive likelihood ratio (LR+).

RESULTS

170 patients with acute arthritis were included. Variables associated with the diagnosis of gout were as follows: serum uric acid > 350 μmol/L (OR 5.52 (2.52-12.1), p < 0.001), joint redness (OR 5.08 (1.85-14.0), p = 0.001), previous patient-reported arthritis attack (OR 4.04 (1.92-8.49), p < 0.001), male (OR 3.00 (1.17-7.69), p = 0.02), hypertension or cardiovascular disease (OR 2.33 (1.07-5.06), p = 0.03). The median (IQR) of Gout-calculator was significantly higher in gouty arthritis (7.0 [5.5-8.1]) than in associated-CPP acute arthritis (4.0 [2.0-5.8]), septic arthritis (3.0 [2.0-5.1]), or others arthritis (3.5 [2.0-5.5]). The AUC was 0.833 (0.768-0.897) with for the threshold ≥ 8, a Se at 27.5% (0.161-0.428), Sp 97.7% (0.934-0.992), and LR+ 11.9 (3.5-40).

CONCLUSION

Despite diagnostic performances close to those published, the use of the Gout-calculator is not sufficient for the diagnosis of gout or to exclude the differential diagnosis of septic arthritis in the SYNOLACTATE cohort.

KEY POINTS

• For a Gout-calculator threshold of ≤ 4, Sensitivity is 92.5%, Specificity 50.8% and LR- 0.15 to the gout diagnosis. • For a Gout-calculator threshold of > = 8, Sensitivity is 27.5%, Specificity 97.7% and LR+ 11.9 to the gout diagnosis. • In a population of acute arthritis affecting large joints, Gout-calculator is not sufficient to discriminate between gouty arthritis and septic arthritis.

FRI0449 MANAGEMENT AND OUTCOME OF SEPTIC ARTHRITIS OF NATIVE JOINT: A NATIONWIDE SURVEY

Background:

Objectives:

To describe current management and outcome of septic arthritis on native joint in French rheumatology departments.

Methods:

Retrospective, nation-wide multicentric study. 127 French rheumatology departments were contacted to report 10 successive cases of septic arthritis on native joint that occurred between the 01/01/16 to 31/12/17 (excluding mycobacteria). Characteristics, diagnosis procedure, therapeutic management and outcome were recorded.

Results:

52 centers included 363 patients (mean age 64± 18.7 years, mean Charlson comorbidity index 4±3). 28.3% patients had a preexisting arthropathy on affected joint. Monoarthritis was observed in 89.6% patients, knee was the most frequent site (38.9%). The most frequent pathogens wereStaphylococcus sp(50.7%) andStreptococcus sp.(23.3%). Bacteremia was found in 156 (45.1%) patients and endocarditis in only 12 (3.0%). Management was heterogeneous. All patients received antibiotics for a mean duration of 46.7±22 days (including intravenous route: 17.3±15.4 d). An initial monotherapy was administered in 42.3% of patients. Surgical procedure (mostly lavage 70.6%) was performed in 171 (48.3%), joint immobilization in 128 (35.3%) (median duration of 21.7±14.1 days). 94 (29.2%) patients have had serious complications including 29 (9.5%) death. Factors associated with death are reported in the table.

Conclusion:

This study shows that management of septic arthritis is very heterogenous with a still high rate of morbidity and mortality. We identified age, comorbidities, bacteremia and recent antibiotherapy were associated with mortality. Of note, duration of antibiotics was not. Thus, new guidelines are needed in order to facilitate septic arthritis management.

Table:FactorsSurvivor(N=276)Dead(N=29)Univariate analysispAdjusted Odds ratio (95%IC)Multivariate analysispAge65 (16-97)82 (32-98)<0,0011,07 (1,03-1,12)< 0.001Charlson’s index1 (0-12)2 (0-9)0,00011,3 (1,05-1,63)0,018Delay before antibiotic initiation8,5 (0-310)5 (0-75)0,04840,99 (0,96-1,02)0,562Corticosteroid in the previous 3 months13,9%33,3%0,01842,56 (0,75-8,74)0,133Bacteriemia42,4%71,4%0,00615,07 (1,4-18,370,013Antibiotics in the previous 3 months26,6%56,6%0,00566,7 (2,04-22,01)0,002

Disclosure of Interests:

Pauline Richebé: None declared, Sophie Godot: None declared, Guillaume Coiffier: None declared, Pascal GUGGENBUHL: None declared, Denis Mulleman: None declared, Marion Couderc: None declared, Emmanuelle Dernis Speakers bureau: Lilly, Novartis, Valentine Deprez: None declared, Carine Salliot: None declared, Saik Urien: None declared, Rachel Brault: None declared, Adeline Ruyssen-Witrand Grant/research support from: Abbvie, Pfizer, Consultant of: Abbvie, BMS, Lilly, Mylan, Novartis, Pfizer, Sandoz, Sanofi-Genzyme, Emmanuel Hoppe: None declared, Jacques-Eric Gottenberg Grant/research support from: BMS, Pfizer, Consultant of: BMS, Sanofi-Genzyme, UCB, Speakers bureau: Abbvie, Eli Lilly and Co., Roche, Sanofi-Genzyme, UCB, Christian Roux: None declared, Sebastien Ottaviani: None declared, Maxime Breban: None declared, Marie Beaufrere: None declared, Alexia Michaut: None declared, Loic Pauvele: None declared, Christelle Darrieutort: None declared, Daniel Wendling: None declared, Pascal COQUERELLE: None declared, Géraldine Bart: None declared, Elisabeth Gervais: None declared, Vincent Goeb: None declared, Marc Ardizzone: None declared, Edouard Pertuiset: None declared, Sophie Derolez: None declared, Jean Marc Ziza: None declared, René-Marc Flipo Consultant of: Johnson and Johnson, MSD France, Novartis, Sanofi, Speakers bureau: Johnson and Johnson, MSD France, Novartis, Sanofi, Raphaèle Seror Consultant of: BMS UCB Pfizer Roche

Broad-range 16 s rDNA PCR in synovial fluid does not improve the diagnostic performance of septic arthritis in native joints in adults: cross-sectional single-center study in 95 patients

OBJECTIVE

To evaluate the diagnostic performance of bacterial identification by broad-range polymerase chain reaction (PCR) of ribosomal DNA (rDNA) 16 s (16S rDNA PCR) for the diagnosis of septic arthritis on native joints.

METHODS

Patients with acute mono or oligoarthritis who underwent synovial fluid puncture and prospective follow-up allowing definitive diagnosis (septic arthritis, crystal related disease, chronic inflammatory arthritis, undifferentiated arthritis) were recruited in this single-center study. Systematic analysis of synovial fluid included leukocytes count, search for urate and pyrophosphate crystals with polarized light microscopy, direct bacteriological examination (gram staining), bacteriological culture, and 16S rDNA PCR.

RESULTS

Ninety-five patients were included, 34 of which (35.8%) had septic arthritis. Nineteen (20.0%) patients had received probabilistic antibiotic therapy prior to joint puncture. Gram + cocci infection accounted for 79.4% of septic arthritis, of which nearly half (47.1%) was caused by Staphylococcus aureus. Eight (23.5%) septic arthritis patients had a 16S rDNA PCR positive in the synovial fluid with an AUC of 0.618 (95% CI, 0.493-0.742), a sensitivity of 0.24 (95% CI, 0.12-0.40), and a specificity of 1.00 (95% CI 0.94-1.00). The diagnostic performance of 16S rDNA PCR was lower than that of direct examination (AUC at 0.691, CI 95%, 0.570-0.812), blood cultures (AUC at 0.727, CI 95%, 0.610-0.844), and culture (0.925, CI 95%, 0.856-0.994) for the diagnosis of septic arthritis. There was no difference in the positivity of 16S rDNA PCR according to previous exposure to antibiotics.

CONCLUSIONS

16 s rDNA PCR in the synovial fluid does not improve the diagnostic performance of septic arthritis on native adult joints, particularly for Gram-positive cocci infections.

Iron excess upregulates SPNS2 mRNA levels but reduces sphingosine-1-phosphate export in human osteoblastic MG-63 cells

We aimed to study the mechanisms involved in bone-related iron impairment by using the osteoblast-like MG-63 cell line. Our results indicate that iron impact the S1P/S1PR signalizing axis and suggest that iron can affect the S1P process and favor the occurrence of osteoporosis during chronic iron overload.

INTRODUCTION

Systemic iron excess favors the development of osteoporosis, especially during genetic hemochromatosis. The cellular mechanisms involved are still unclear despite numerous data supporting a direct effect of iron on bone biology. Therefore, the aim of this study was to characterize mechanisms involved in the iron-related osteoblast impairment.

METHODS

We studied, by using the MG-63 cell lines, the effect of iron excess on SPNS2 gene expression which was previously identified by us as potentially iron-regulated. Cell-type specificity was investigated with hepatoma HepG2 and enterocyte-like Caco-2 cell lines as well as in iron-overloaded mouse liver. The SPNS2-associated function was also investigated in MG-63 cells by fluxomic strategy which led us to determinate the S1P efflux in iron excess condition.

RESULTS

We showed in MG-63 cells that iron exposure strongly increased the mRNA level of the SPNS2 gene. This was not observed in HepG2, in Caco-2 cells, and in mouse livers. Fluxomic study performed concomitantly on MG-63 cells revealed an unexpected decrease in the cellular capacity to export S1P. Iron excess did not modulate SPHK1, SPHK2, SGPL1, or SGPP1 gene expression, but decreased COL1A1 and S1PR1 mRNA levels, suggesting a functional implication of low extracellular S1P concentration on the S1P/S1PR signalizing axis.

CONCLUSIONS

Our results indicate that iron impacts the S1P/S1PR signalizing axis in the MG-63 cell line and suggest that iron can affect the bone-associated S1P pathway and favor the occurrence of osteoporosis during chronic iron overload.

Pregnancy-related fractures: a retrospective study of a French cohort of 52 patients and review of the literature

A retrospective, multicentre study involving 52 patients was carried out to define the causes and characteristics of pregnancy-related osteoporosis. The mean number of vertebral fractures occurring during the last trimester of pregnancy or at the time of delivery was 3.8. This is often promoted by risk factors before or during pregnancy.

INTRODUCTION

In order to define the causes or predisposing factors of pregnancy-related osteoporosis and its clinical, radiological and bone density characteristics, laboratory findings, course and outcome, we carried out a retrospective multicentre study.

METHODS

The records of 52 women hospitalised over the last 10 years in the rheumatology departments of six French university hospitals and with a diagnosis of pregnancy-related osteoporosis were examined.

RESULTS

The patients' mean age at time of fracture was 32.1 years. In 10 patients, the fractures had occurred during the last trimester of pregnancy, and in 36 at the time of delivery or during the first 2 months post-partum. The mean number of vertebral fractures was 3.8 ± 2.0. Thirty three of the 52 patients had a risk factor of low bone mass before pregnancy. Twelve had disorders or treatments (heparin) that might promote osteoporosis during pregnancy, while 14 had no trigger factors before or during pregnancy. Overall, phosphate and calcium levels were normal, except for hyperphosphoraemia in lactating women (90%). On DXA scan, osteoporosis predominated in the trabecular bone (spinal T-score - 3.4, hip T-score - 2). Only 10 patients had a repeat fracture, and the increase in bone mineral density during follow-up was considerable, and improved by bisphosphonates (annual gain + 10% in the spine) or teriparatide (+ 15%).

CONCLUSIONS

Pregnancy-related osteoporosis gives rise to multiple vertebral fractures. It is often promoted by risk factors before or during pregnancy. Its mechanism is still unknown. Treatment with bisphosphonates or teriparatide appears to improve the recovery of bone mineral density.

Low-trauma fractures without osteoporosis

In clinical practice, areal bone mineral density (aBMD) is usually measured using dual-energy X-ray absorptiometry (DXA) to assess bone status in patients with or without osteoporotic fracture. As BMD has a Gaussian distribution, it is difficult to define a cutoff for osteoporosis diagnosis. Based on epidemiological considerations, WHO defined a DXA-based osteoporosis diagnosis with a T-score <-2.5. However, the majority of individuals who have low-trauma fractures do not have osteoporosis with DXA (i.e., T-score <-2.5), and some of them have no decreased BMD at all. Some medical conditions (spondyloarthropathies, chronic kidney disease and mineral bone disorder, diabetes, obesity) or drugs (glucocorticoids, aromatase inhibitors) are more prone to cause fractures with subnormal BMD. In the situation of fragility fractures with subnormal or normal BMD, clinicians face a difficulty as almost all the pharmacologic treatments have proved their efficacy in patients with low BMD. However, some data are available in post hoc analyses in patients with T score >-2. Overall, in patients with a previous fragility fracture (especially vertebra or hip), treatments appear to be effective. Thus, the authors recommend treating some patients with a major fragility fracture even if areal BMD T score is above -2.5.

Use of near infrared reflectance spectroscopy to predict phytate phosphorus, total phosphorus, and crude protein of common poultry feed ingredients

The purpose of the study that is presented herein was to develop near-infrared reflectance spectroscopy (NIRS) calibrations to predict total phosphorus (P), phytate-P, and protein concentrations of feed ingredients commonly used in monogastric feed formulation. Samples representing 14 vegetable ingredients (cereals, cereal by-products, and oilseed meals) were collected worldwide throughout 2013. The samples were assayed by standard wet chemical techniques for total P, phytate-P, and protein content. There was substantial variability in protein, phytate-P, and total P within and between ingredients used in the calibration set. Protein content varied from 76 to 487 g/kg. Total P ranged from 2.09 and 22.5 g/kg and phytate-P ranged from 0.99 and 13.8 g/kg. Within these broad ranges, NIRS values were highly correlated for determination of protein, total P, and phytate-P with a standard error of prediction equal to 9.06 g/kg, 0.80 g/kg, and 0.66 g/kg, respectively. The wide diversity and heterogeneity of the mix of feed ingredients allowed the development of NIRS calibrations of sufficient accuracy to help nutritionists control the nutritional composition of their feed.

Possible involvement of myo-inositol in the physiological response of broilers to high doses of microbial phytase

The effect of high (1000–3000 phytase units (FYT)/kg) doses of microbial phytase on performance, nutrient digestibility and plasma inositol concentrations in young Ross broiler chicks was investigated in two separate experiments. In both experiments pelleted corn/soy-based diets were used and experimental duration was from Days 8 to 21 and Days 15 to 28 in Experiments 1 and 2, respectively. Treatments in Experiment 1 were arranged as a 2 × 4 + 1 factorial with two concentrations of calcium and available phosphorus and four concentrations of phytase (0, 1000, 2000 or 3000 FYT/kg), with a reference diet containing additional phosphorus and calcium from inorganic sources. In Experiment 2 only four dietary treatments were used, being a nutritionally adequate positive control, a negative control formulated to be insufficient in calcium and available phosphorus and the negative control supplemented with either 1000 or 2000 FYT/kg exogenous phytase. In both experiments, phytase improved performance relative to the appropriate control diet and increased the retention of calcium and phosphorus (P < 0.001). Tibia strength and ash content were increased (P < 0.001) by phytase addition. Plasma inositol concentrations were substantially increased (P < 0.001) by phytase addition to the diet. As inositol has been found to be an insulin mimetic in a range of animal species, these results suggest that part of the beneficial effect of high doses of phytase in broiler production may be conferred via insulin-like mechanisms. The effect of phytase on the expression of insulin-sensitive glucose transport systems, gluconeogenesis and nitrogen cycling is an area for future research. It can be concluded that phytase is effective in improving performance of broiler chicks fed diets that are sufficient and insufficient in calcium and phosphorus. Furthermore, phytase addition results in increased plasma inositol concentrations that may be beneficial in nutrient transport and protein deposition.

Effects of dietary supplementation with a protease on the apparent ileal digestibility of the weaned piglet

The effects of an acid-stable protease (RONOZYME ProAct) supplemented to a corn (Zea mays)-soybean (Glycine max) meal-based diet on apparent ileal digestibility (AID) of nutrients were evaluated in 120 weaned piglets (28 d old; 8.17 ± 0.90 kg). Pigs were divided into 2 equal groups and had free access to mash diet containing 0.4% Cr(2)O(3) as indigestible marker [basal diet (Std)] or this diet supplemented with RONOZYME ProAct at 15,000 PROT [the amount of enzyme that releases 1 μmol of pnitroaniline from 1 μM of substrate (Suc-Ala-Ala-Pro-Phe-p-nitroaniline) per min at pH 9.0 and 37°C)/kg (ProA). The ileal content was collected for the digestibility determination after euthanasia of 35 piglets of each group after 14 d of study and 25 piglets of each group after 29 d. Compared to group Std, AID of CP was increased (P < 0.05) after 29 d of treatment in group ProA. The AID of the indispensable AA, Met + Cys, and branched-chain AA was increased (P < 0.05) at the end of the study. In the protease supplemented pigs, the AID of the individual AA was not improved after 14 d of treatment whereas it was increased (P < 0.05) at the end of the experiment for Arg, Asp + Asn, Glu + Gln, His, Ile, Lys, Phe, Thr, Tyr ,and Val. In conclusion, dietary protease supplementation increased AID of AA in piglets.

The degradation of arabinoxylan-rich cell walls in digesta obtained from piglets fed wheat-based diets varies depending on digesta collection site, type of cereal, and source of exogenous xylanase

The objective of the present study was to compare the ability of experimental and commercial xylanases to degrade, in vitro, the arabinoxylan (AX) fraction in digesta from 28-d-old piglets fed a wheat (Triticum aestivum)-based diet (49% wheat). Pigs were euthanized at 1, 2, 3, or 4 h after feeding; stomach and ileum contents were isolated and frozen and later used for the in vitro studies. Xylan solubilization provided information regarding the ability of the enzymes to degrade AX during the harsh in vivo conditions prevailing in the gastrointestinal tract. The hydrolytic capacity of a commercial xylanase was compared with that of an experimental xylanase using stomach digesta (pH 1.8) obtained at 4 h after feeding. Relative to the control, both enzymes increased (P < 0.001) xylan solubilization 3-fold. In the ileal digesta (1 h), xylan solubilization was increased by 36% (P < 0.001). Inclusion of arabinofuranosidases (Ara f) with xylanases increased xylan solubilization in stomach samples (P = 0. 007 and P = 0. 030) but not in ileal samples (P = 0.873 and P = 0.997). Our results illustrate clearly the importance of using different conditions and substrates when enzyme performance is studied in vitro as a prescreening tool for setting up in vivo trials.

Effects of a 6-phytase on the apparent ileal digestibility of minerals and amino acids in ileorectal anastomosed pigs fed on a corn-soybean meal-barley diet

Phosphorus of plant-based feedstuffs for monogastric animals is mainly in the form of phytic P, which has a very low bioavailability. The nondigested phytic P may contribute to P pollution. Furthermore, phytic acid may reduce digestibility of other minerals and protein. This study evaluated effects of the microbial 6-phytase RONOZYME HiPhos on apparent ileal digestibility of P, phytic acid, Ca, CP, energy, and AA in six 60-d-old ileorectal anastomosed pigs. In a duplicated 3 × 3 Latin square design, pigs had free access to alternatively a corn (Zea mays)-soybean (Glycine max) meal-barley (Hordeum vulgare)-based diet or this diet supplemented with RONOZYME HiPhos at either 500 units/kg (RH500) or 1000 units/kg (RH1000). Pigs fed diets supplemented with RH500 or RH1000 increased (P < 0.05) digestibility of P, Ca, and Lys. Pigs fed diet RH1000 increased (P < 0.05) digestibility of CP, total AA, indispensable AA, Glu + Gln, His, Gly, Ala, Tyr, Leu, Phe, and Met. Similar to growth trials with increased total tract digestibility of P and Ca, phytase increased apparent ileal digestibility of these indispensable minerals and phytate. The phytase increased digestibility of CP and indispensable AA indicating a better availability of plant-based proteins.

Iron excess limits HHIPL-2 gene expression and decreases osteoblastic activity in human MG-63 cells

In order to understand mechanisms involved in osteoporosis observed during iron overload diseases, we analyzed the impact of iron on a human osteoblast-like cell line. Iron exposure decreases osteoblast phenotype. HHIPL-2 is an iron-modulated gene which could contribute to these alterations. Our results suggest osteoblast impairment in iron-related osteoporosis.

INTRODUCTION

Iron overload may cause osteoporosis. An iron-related decrease in osteoblast activity has been suggested.

METHODS

We investigated the effect of iron exposure on human osteoblast cells (MG-63) by analyzing the impact of ferric ammonium citrate (FAC) and iron citrate (FeCi) on the expression of genes involved in iron metabolism or associated with osteoblast phenotype. A transcriptomic analysis was performed to identify iron-modulated genes.

RESULTS

FAC and FeCi exposure modulated cellular iron status with a decrease in TFRC mRNA level and an increase in intracellular ferritin level. FAC increased ROS level and caspase 3 activity. Ferroportin, HFE and TFR2 mRNAs were expressed in MG-63 cells under basal conditions. The level of ferroportin mRNA was increased by iron, whereas HFE mRNA level was decreased. The level of mRNA alpha 1 collagen type I chain, osteocalcin and the transcriptional factor RUNX2 were decreased by iron. Transcriptomic analysis revealed that the mRNA level of HedgeHog Interacting Protein Like-2 (HHIPL-2) gene, encoding an inhibitor of the hedgehog signaling pathway, was decreased in the presence of FAC. Specific inhibition of HHIPL-2 expression decreased osteoblast marker mRNA levels. Purmorphamine, hedgehog pathway activator, increased the mRNA level of GLI1, a target gene for the hedgehog pathway, and decreased osteoblast marker levels. GLI1 mRNA level was increased under iron exposure.

CONCLUSION

We showed that in human MG-63 cells, iron exposure impacts iron metabolism and osteoblast gene expression. HHIPL-2 gene expression modulation may contribute to these alterations. Our results support a role of osteoblast impairment in iron-related osteoporosis.

Bone status in a mouse model of genetic hemochromatosis

Genetic hemochromatosis is a cause of osteoporosis; mechanisms leading to iron-related bone loss are not fully characterized. We assessed the bone phenotype of HFE (-/-) male mice, a mouse model of hemochromatosis. They had a phenotype of osteoporosis with low bone mass and alteration of the bone microarchitecture.

INTRODUCTION

Genetic hemochromatosis is a cause of osteoporosis. However, the mechanisms leading to iron-related bone loss are not fully characterized. Recent human data have not supported the hypothesis of hypogonadism involvement. The direct role of iron on bone metabolism has been suggested.

METHODS

Our aim was to assess the bone phenotype of HFE (-/-) male mice, a mouse model of human hemochromatosis, by using microcomputed tomography and histomorphometry. HFE (-/-) animals were sacrificed at 6 and 12 months and compared to controls.

RESULTS

There was a significant increase in hepatic iron concentration and bone iron content in HFE (-/-) mice. No detectable Perls' staining was found in the controls' trabeculae. Trabecular bone volume (BV/TV) was significantly lower in HFE (-/-) mice at 6 and 12 months compared to the corresponding wild-type mice: 9.88 ± 0.82% vs 12.82 ± 0.61% (p = 0.009) and 7.18 ± 0.68% vs 10.4 ± 0.86% (p = 0.015), respectively. In addition, there was an impairment of the bone microarchitecture in HFE (-/-) mice. Finally, we found a significant increase in the osteoclast number in HFE (-/-) mice: 382.5 ± 36.75 vs 273.4 ± 20.95 ¢/mm(2) (p = 0.004) at 6 months and 363.6 ± 22.35 vs 230.8 ± 18.7 ¢/mm(2) (p = 0.001) at 12 months in HFE (-/-) mice vs controls.

CONCLUSION

Our data show that HFE (-/-) male mice develop a phenotype of osteoporosis with low bone mass and alteration of the microarchitecture. They suggest that there is a relationship between bone iron overload and the increase of the osteoclast number in these mice. These findings are in accordance with clinical observations in humans exhibiting genetic hemochromatosis and support a role of excess iron in relation to genetic hemochromatosis in the development of osteoporosis in humans.

Longitudinal study of bone mineral density in children after a diagnosis of Crohn's disease

AIM

The purpose of this study was to measure the bone mineral density (BMD) of children with Crohn's disease (CD) and to prospectively assess its evolution.

PATIENTS AND METHODS

A total of 27 children (20 boys, seven girls), aged 12.1±2.5 years, were recruited at the time of CD diagnosis. Dual-energy X-ray absorptiometry (DEXA) was used to measure BMD, expressed as Z scores for chronological age (BMD/CA) and bone age (BMD/BA). One year later, BMD was measured again to identify any correlations with disease activity [group A (active disease) vs group R (remission)].

RESULTS

BMD/CA and BMD/BA were negatively correlated with delay in diagnosis (P<0.0001 and P<0.05, respectively). BMD/CA was less than -2 standard deviation (SD) in nine patients and BMD/BA was less -2 SD in four patients. At the follow-up, the increase in BMD was smaller in group A (n=14), whether expressed as absolute values (-0.002 vs 0.040 g/cm(2) per year; P<0.024) or as percentages (-0.2 vs 6.6%; P<0.041); changes in BMD/CA (-0.5 vs -0.1 SD/year) and BMD/BA (-0.3 vs 0 SD/year) did not differ.

CONCLUSION

Diagnostic delay greatly affects BMD in children with CD even prior to corticosteroid therapy. The risk of low BMD increases with persistent CD activity, although the risk is reduced in association with bone maturation delay.

High-energy extracorporeal shock-wave therapy for calcifying tendinitis of the rotator cuff

In a prospective randomised trial of calcifying tendinitis of the rotator cuff, we compared the efficacy of dual treatment sessions delivering 2500 extracorporeal shock waves at either high- or low-energy, via an electromagnetic generator under fluoroscopic guidance. Patients were eligible for the study if they had more than a three-month history of calcifying tendinitis of the rotator cuff, with calcification measuring 10 mm or more in maximum dimension. The primary outcome measure was the change in the Constant and Murley Score.

A total of 80 patients were enrolled (40 in each group), and were re-evaluated at a mean of 110 (41 to 255) days after treatment when the increase in Constant and Murley score was significantly greater (t-test, p = 0.026) in the high-energy treatment group than in the low-energy group. The improvement from the baseline level was significant in the high-energy group, with a mean gain of 12.5 (−20.7 to 47.5) points (p < 0.0001). The improvement was not significant in the low-energy group. Total or subtotal resorption of the calcification occurred in six patients (15%) in the high-energy group and in two patients (5%) in the low-energy group.

High-energy shock-wave therapy significantly improves symptoms in refractory calcifying tendinitis of the shoulder after three months of follow-up, but the calcific deposit remains unchanged in size in the majority of patients.

Texture analysis of X-ray radiographs of iliac bone is correlated with bone micro-CT

INTRODUCTION

Alteration of bone trabecular architecture is a predictor of fracture risk in osteoporosis. Until now, microarchitecture can only be measured on a bone biopsy, thus limiting microarchitecture analysis in routine clinical practice for osteoporosis. Texture analysis on X-ray images has been advocated to be a suitable means to assess two-dimensional (2-D) microarchitecture in the research field. But little is known about the relationships between three-dimensional (3-D) architecture and texture analysis, particularly in clinical practice. The purposes of the study were: (1) to explore the relationship between 3-D histomorphometric parameters and 2-D texture analysis, and (2) to see if cortical assessment may influence results.

METHODS

In this study, the anterosuperior part of the iliac bone was removed from 24 cadavers. Large samples were prepared and comprised of the crest and a strip of bone approximately 3 cm wide and 5 cm long. These large specimens were used in order to preserve bone architecture; they also corresponded to the location used by histomorphometrists for the diagnosis of metabolic bone diseases on iliac crest biopsies. Bone samples were examined with a microcomputed tomograph for 3-D microarchitecture [BV/TV, C.BV/C.TV, Tb.P(f), structure model index (SMI), Tb.Th, Tb.N, Tb.Sp]. Texture analysis was done by several methods (skeletonization, run lengths, fractal techniques) from X-ray projection images. No correlation was found between bone mass parameters (BV/TV and C.BV/C.TV, which take into account both cortical and trabecular bone) and texture parameters.

RESULTS

However, when specific descriptors of trabecular bone microarchitecture were used, several relationships with texture parameters were found [(Tb.N)/BOUND, r=0.628;/VGLN, r=0.596;/Fractal D, r=0.569].

CONCLUSION

When multiple correlations were used, the correlation coefficients were markedly improved with trabecular characteristics. X-ray texture analysis seemed to be a suitable approach for 2-D bone microarchitecture assessment. Furthermore, there is a good correlation between texture analysis of X-ray radiographs and 3-D bone microarchitecture assessed by microcomputed tomography.

Bone mineral density in men with genetic hemochromatosis and HFE gene mutation

Genetic hemochromatosis (GH) is an iron overload disorder mainly due to the C282Y mutation of the HFE gene. The possibility of bone involvement was only recently recognized. The aims of this study were to assess bone mineral density (BMD) and bone remodeling in men with GH, and to examine the influence of iron overload. Thirty-eight men (mean age 47.2+/-9.4 years) with well-defined HFE-related GH were studied. They had an important iron overload with liver iron concentration to age ratio >2.5, no previous venesection therapy and were C282Y homozygotes (n=37) or compound C282Y/H63D heterozygote (n=1). BMD measured by DXA was 0.925+/-0.15 g/cm2 at the lumbar spine (LS) and 0.778+/-0.13 g/cm2 at the femoral neck (FN). Osteopenia (T-score<-1 SD) was observed in 78.9% of patients and osteoporosis (T-score<-2.5 SD) in 34.2%. Vitamin D levels were normal, and no 1-84 parathyroid hormone dysfunction was found. Hypogonadism was found in only 13.2% of patients. Patients with hypogonadism had lower LS BMD than eugonadal patients (0.788+/-0.16 and 0.954+/-0.14 g/cm2). Bone remodeling and parathyroid hormone levels were lower in patients with cirrhosis, but BMD values were similar to those in patients without cirrhosis. FN BMD appeared to fall with rising hepatic iron concentrations (r=-0.399). We conclude that there is significant bone loss in HFE-related hemochromatosis that cannot solely be explained by hypogonadism or cirrhosis. Further investigations are needed to determine the role of iron overload itself.

Diagnostic value of serum and synovial procalcitonin in acute arthritis: a prospective study of 42 patients

OBJECTIVE

To determine the diagnostic value of serum and synovial procalcitonin (PCT) for bacterial arthritis and to determine the cellular origin of synovial PCT.

METHODS

A prospective study enrolled 42 patients with acute arthritis including 11 bacterial arthritis, 18 rheumatoid arthritis and 13 crystal induced arthritis. Diagnostic values of serum and synovial PCT levels were determined by a immunoluminometric assay (Lumitest PCT) and compared to those of classical inflammatory markers (C-reactive protein, erythrocyte sedimentation rate, synovial fluid cellularity and both serum and synovial IL-6 and TNF alpha). Using fibroblast-like synoviocyte (FLS) cultures derived from rheumatoid arthritis (n = 4) and osteo-arthritis (n = 3) synovium, with or without stimulation by lipopolysaccharid or recombinant streptococcal protein 1/II, we attempted to determine whether synovial cells could be a source of PCT.

RESULTS

Serum PCT was the best parameter to distinguish patients with acute bacterial arthritis from patients with crystal induced arthritis or rheumatoid arthritis. In setting of an acute arthritis serum PCT (> 0.5 ng/mL) achieved 55% sensitivity and 94% specificity for the diagnosis of bacterial arthritis, while CRP (> 50 mg/L) had 100% sensitivity but poor specificity (40%). Serum PCT appeared to be higher in patients with septic arthritis resulting from "systemic infection" than in cases resulting from direct inoculation. Synovial PCT was not useful to discriminate between infectious and non infectious arthritis in clinical practice. PCT could not be detected at significant levels in the conditioned medium from fibroblast-like synoviocyte cultures.

CONCLUSION

Serum PCT is a poorly sensitive but specific marker of bacterial arthritis. Use of serum PCT in association with CRP could nevertheless be useful in an emergency situation for the diagnosis of bacterial arthritis.

Prevalence of spondyloarthropathies in France: 2001

OBJECTIVE

To estimate the prevalence of spondyloarthropathies (SpAs) in France in a multiregional representative sample in the year 2001.

METHODS

A two stage random sample was constituted in seven areas from the national telephone directory and the next birthday method in each household. Interviewers were patient-members of self help groups trained to administer telephone surveys using a validated questionnaire for detecting inflammatory joint disease. Quality of data collection was controlled periodically. SpA was confirmed by the patient's rheumatologist or by clinical examination. Prevalence estimates after probability sampling correction were standardised for age and sex (1999 national census).

RESULTS

Among the 15 219 anonymous telephone numbers selected, 3.6% were places of work or secondary residences and were excluded. The phone interview participation rate ranged across regions from 55.1 to 69.9%. 3554 men and 5841 women were included in the study. Twenty nine cases of SpA were confirmed. All but one fulfilled ESSG criteria. Mean age was 47 years (range 21-78). The overall prevalence standardised for age and sex was 0.30% (95% confidence interval (CI) 0.17 to 0.46). Prevalence was similar in women (0.29% (95% CI 0.14 to 0.49)) and men (0.31 % (95% CI 0.12 to 0.60)). Geographical analysis by department clustering found no significant differences. The prevalence of SpA was as high as that of rheumatoid arthritis.

CONCLUSION

Prevalence of SpA in France was 0.30% in 2001, with no difference between women and men. Ankylosing spondylitis and psoriatic arthritis were the most common SpA subsets.

Prevalence of rheumatoid arthritis in France: 2001

BACKGROUND

Prevalence estimates of rheumatoid arthritis (RA) vary across Europe. Recent estimates in southern European countries showed a lower prevalence than in northern countries.

OBJECTIVES

To estimate the prevalence of RA in France in a multiregional representative sample in the year 2001.

METHODS

A two stage random sample was constituted in seven areas (20 counties) from the national telephone directory of households and by the next birthday method in each household. Patient-interviewers, member of self help groups, were trained to administer telephone surveys using a validated questionnaire for case detection of inflammatory rheumatism, and conducted the survey under quality control. All suspected cases of RA were confirmed by their rheumatologist or by clinical examination. Prevalence estimates after probability sampling correction were standardised for age and sex (national census 1999).

RESULTS

An average response rate of 64.7% (two stages combined) led to a total of 9395 respondents. Standardised prevalence was 0.31% (95% confidence interval 0.18 to 0.48) for RA, 0.51% in women and 0.09% in men, with a higher age-specific prevalence in the 65-74 year age band. A geographical analysis of county clustering showed significant variation across the country.

CONCLUSION

This national multiregional cooperative study demonstrates the usefulness of working in association with patients of self help groups. It showed a similar prevalence of RA to that of the spondyloarthropathies estimated concomitantly during the survey. It provides a reliable basis for definition of population targets for healthcare delivery and drug treatments.

Characteristics of fungal phytases from Aspergillus fumigatus and Sartorya fumigata

Aspergillus fumigatus phytase has previously been identified as a phytase with a series of favourable properties that may be relevant in animal and human nutrition, both for maximising phytic acid degradation and for increasing mineral and amino acid availability. To study the natural variability in amino acid sequence and its impact on the catalytic properties of the enzyme, we cloned and overexpressed the phytase genes and proteins from six new purported A. fumigatus isolates. Five of these phytases displayed < or= 2 amino acid substitutions and had virtually identical stability and catalytic properties when compared with the previously described A. fumigatus ATCC 13073 phytase. In contrast, the phytase from isolate ATCC 32239 ( Sartorya fumigata, the anamorph of which was identified as A. fumigatus) was more divergent (only 86% amino acid sequence identity), had a higher specific activity with phytic acid, and displayed distinct differences in substrate specificity and pH-activity profile. Finally, comparative experiments confirmed the favourable stability and catalytic properties of A. fumigatus phytase.