Proinflammatory cytokines and receptor activator of nuclear factor kappaB-ligand/osteoprotegerin associated with bone deterioration in patients with Crohn's disease

Evaluating the potential of Vitamin D and curcumin to alleviate inflammation and mitigate the progression of osteoarthritis through their effects on human chondrocytes: A proof-of-concept investigation

Osteoarthritis (OA) is a chronic degenerative joint disorder primarily affecting the elderly, characterized by a prominent inflammatory component. The long-term side effects associated with current therapeutic approaches necessitate the development of safer and more efficacious alternatives. Nutraceuticals, such as Vitamin D and curcumin, present promising therapeutic potentials due to their safety, efficacy, and cost-effectiveness. In this study, we utilized a proinflammatory human chondrocyte model of OA to assess the anti-inflammatory properties of Vitamin D and curcumin, with a particular focus on the Protease-Activated Receptor-2 (PAR-2) mediated inflammatory pathway. Employing a robust siRNA approach, we effectively modulated the expression of PAR-2 to understand its role in the inflammatory process. Our results reveal that both Vitamin D and curcumin attenuate the expression of PAR-2, leading to a reduction in the downstream proinflammatory cytokines, such as Tumor Necrosis Factor-alpha (TNF-α), Interleukin 6 (IL-6), and Interleukin 8 (IL-8), implicated in the OA pathogenesis. Concurrently, these compounds suppressed the expression of Receptor Activator of Nuclear Factor kappa-Β Ligand (RANKL) and its receptor RANK, which are associated with PAR-2 mediated TNF-α stimulation. Additionally, Vitamin D and curcumin downregulated the expression of Interferon gamma (IFN-γ), known to elevate RANKL levels, underscoring their potential therapeutic implications in OA. This study, for the first time, provides evidence of the mitigating effect of Vitamin D and curcumin on PAR-2 mediated inflammation, employing an siRNA approach in OA. Thus, our findings pave the way for future research and the development of novel, safer, and more effective therapeutic strategies for managing OA.

Risk Factors for Osteoporosis among Patients with Inflammatory Bowel Disease-Do We Already Know Everything?

INTRODUCTION

There are many known risk factors for osteoporosis (OST) among patients with inflammatory bowel disease (IBD), one of which is physical activity.

MATERIAL AND METHODS

The aim of the study is to assess the frequency and risk factors of OST among 232 patients with IBD compared to a group of 199 patients without IBD. The participants underwent dual-energy X-ray absorptiometry, laboratory tests, and completed a questionnaire about their physical activity.

RESULTS

It was found that 7.3% of IBD patients suffered from OST. Male gender, ulcerative colitis, extensive inflammation in the intestine, exacerbation of disease, rare physical activity, other forms of physical activity, past fractures, lower levels of osteocalcin, and higher levels of C-terminal telopeptide of type 1 collagen were risk factors for OST. As many as 70.6% of OST patients were rarely physically active.

CONCLUSIONS

OST is a common problem in IBD patients. OST risk factors differ significantly between the general population and those with IBD. Modifiable factors can be influenced by patients and by physicians. The key to OST prophylaxis may be regular physical activity, which should be recommended in clinical remission. It may also prove valuable to use markers of bone turnover in diagnostics, which may enable decisions regarding therapy.

Osteoporosis Complications in Crohn's Disease Patients: Factors, Pathogenesis, and Treatment Outlines

The causes of osteoporosis in Crohn’s disease (CD) are multifactorial; cytokines, steroids, and vitamin deficiency all have an essential role. It is imperative to distinguish the factors that contribute to bone resorption, potentially increasing the risk of low bone mineral density (BMD), osteoporosis, and fracture. However, the pathogenicity of osteoporosis associated with CD remains unclear. Although osteoporosis treatment may vary between bisphosphonate and corticosteroid, infliximab's efficacy, when combined with immune modulators, suppresses both CD symptoms and osteoporosis progression. In this review, we aim to understand the present pathogenicity of osteoporosis, including the factors pro-inflammatory cytokines, chronic steroid use, and malnutrition, developing osteoporosis in a different pathological way, and to assist the treatment lines implying a positive outcome of osteoporosis in CD patients.

Osteoporosis is considered to be one of the early complications of CD where early detection can prevent osteoporosis progression. This can be done by utilizing dual-energy X-ray-absorptiometry (DEXA) to evaluate the Z-score and treat the existing factors that have a role in the progression of osteoporosis in CD patients.

Pathogenesis of Musculoskeletal Deficits in Children and Adults with Inflammatory Bowel Disease

Musculoskeletal deficits are among the most commonly reported extra-intestinal manifestations and complications of inflammatory bowel disease (IBD), especially in those with Crohn’s disease. The adverse effects of IBD on bone and muscle are multifactorial, including the direct effects of underlying inflammatory disease processes, nutritional deficits, and therapeutic effects. These factors also indirectly impact bone and muscle by interfering with regulatory pathways. Resultantly, individuals with IBD are at increased risk of osteoporosis and sarcopenia and associated musculoskeletal morbidity. In paediatric IBD, these factors may contribute to suboptimal bone and muscle accrual. This review evaluates the main pathogenic factors associated with musculoskeletal deficits in children and adults with IBD and summarises the current literature and understanding of the musculoskeletal phenotype in these patients.

Decreased Expression of the Human Urea Transporter SLC14A1 in Bone is Induced by Cytokines and Stimulates Adipogenesis of Mesenchymal Progenitor Cells

The human urea transporter SLC14A1 (HUT11/UT-B) has been suggested as a marker for the adipogenic differentiation of bone cells with a relevance for bone diseases. We investigated the function of SLC14A1 in different cells models from bone environment. SLC14A1 expression and cytokine production was investigated in bone cells obtained from patients with osteoporosis. Gene and protein expression of SLC14A1 was studied during adipogenic or osteogenic differentiation of human mesenchymal progenitor cells (hMSCs) and of the single-cell-derived hMSC line (SCP-1), as well as in osteoclasts and chondrocytes. Localization was determined by histochemical methods and functionality by urea transport experiments. Expression of SLC14A1 mRNA was lower in cells from patients with osteoporosis that produced high levels of cytokines. Accordingly, when adding a combination of cytokines to SCP-1 SLC14A1 mRNA expression decreased. SLC14A1 mRNA expression decreased after both osteogenic and more pronounced adipogenic stimulation of hMSCs and SCP-1 cells. The highest SLC14A1 expression was determined in undifferentiated cells, lowest in chondrocytes and osteoclasts. Downregulation of SLC14A1 by siRNA resulted in an increased expression of interleukin-6 and interleukin-1 beta as well as adipogenic markers. Urea influx through SLC14A1 increased expression of osteogenic markers, adipogenic markers were suppressed. SLC14A1 protein was localized in the cell membrane and the cytoplasm. Summarizing, the SLC14A1 urea transporter affects early differentiation of hMSCs by diminishing osteogenesis or by favoring adipogenesis, depending on its expression level. Therefore, SLC14A1 is not unequivocally an adipogenic marker in bone. Our findings suggest an involvement of SLC14A1 in bone metabolism and inflammatory processes and disease-dependent influences on its expression.

RANKL/RANK/OPG Pathway: A Mechanism Involved in Exercise-Induced Bone Remodeling

Bones as an alive organ consist of about 70% mineral and 30% organic component. About 200 million people are suffering from osteopenia and osteoporosis around the world. There are multiple ways of protecting bone from endogenous and exogenous risk factors. Planned physical activity is another useful way for protecting bone health. It has been investigated that arranged exercise would effectively regulate bone metabolism. Until now, a number of systems have discovered how exercise could help bone health. Previous studies reported different mechanisms of the effect of exercise on bone health by modulation of bone remodeling. However, the regulation of RANKL/RANK/OPG pathway in exercise and physical performance as one of the most important remodeling systems is not considered comprehensive in previous evidence. Therefore, the aim of this review is to clarify exercise influence on bone modeling and remodeling, with a concentration on its role in regulating RANKL/RANK/OPG pathway.

Azathioprine Has a Deleterious Effect on the Bone Health of Mice with DSS-Induced Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) often present poor bone health and are 40% more at risk of bone fracture. Studies have implicated autophagy in IBD pathology and drugs used to treat IBD stimulate autophagy in varying degrees, however, their effect on the skeleton is currently unknown. Here, we have utilised the dextran sulphate sodium (DSS) model of colitis in mice to examine the effects of the thiopurine drug azathioprine on the skeleton. Ten-week-old male mice (n = 6/group) received 3.0% DSS in their drinking water for four days, followed by a 14-day recovery period. Mice were treated with 10 mg/kg/day azathioprine or vehicle control. Histopathological analysis of the colon from DSS mice revealed significant increases in scores for inflammation severity, extent, and crypt damage (p < 0.05). Azathioprine provided partial protection to the colon, as reflected by a lack of significant difference in crypt damage and tissue regeneration with DSS treatment. MicroCT of vehicle-treated DSS mice revealed azathioprine treatment had a significant detrimental effect on the trabecular bone microarchitecture, independent of DSS treatment. Specifically, significant decreases were observed in bone volume/tissue volume (p < 0.01), and trabecular number (p < 0.05), with a concurrent significant increase in trabecular pattern factor (p < 0.01). Immunohistochemical labelling for LC3 revealed azathioprine to induce autophagy in the bone marrow. Together these data suggest that azathioprine treatment may have a deleterious effect on IBD patients who may already be at increased risk of osteoporotic bone fractures and thus will inform on future treatment strategies for patient stratification.

Crohn's disease patient serum changes protein expression in a human mesenchymal stem cell model in a linear relationship to patients' disease stage and to bone mineral density

BACKGROUND

Crohn's disease (CD) is associated with a higher prevalence of osteoporosis, a complication that is recognized as a significant cause of morbidity. Its pathogenesis is controversial, but the activity of CD is one contributing factor.

METHODS

We stimulated SCP-1 cells (mesenchymal stem cell line) under osteogenic conditions with serum from adult patients with CD in the symptomatic phase (SP) and in remission (R) and with control sera. Concentrations of IL-6, IL-1 beta, and TNF alpha in the sera were measured. Patients were classified as normal or osteopenic/osteoporotic based on bone mineral density (BMD) T-score measurements. After 14 days in culture, protein expression and gene ontology (GO) annotation analysis was performed.

RESULTS

Cytokine concentrations (IL-6, IL-1 beta, TNF alpha) varied within sera groups. None of the cytokines were significantly increased in the symptomatic phase compared to remission. Protein analysis revealed 17 proteins regulated by the SP versus R phase sera of disease. A linear relationship between CDAI (Crohn's disease activity index) and normalized protein expression of APOA1 and 2, TTR, CDKAL1 and TUBB6 could be determined. Eleven proteins were found to be differentially regulated comparing osteoporosis-positive and osteoporosis-negative sera. Gene annotation and further analysis identified these genes as part of heme and erythrocyte metabolism, as well as involved in hypoxia and in endocytosis. A significant linear relationship between bone mineral density and normalized protein expression could be determined for proteins FABP3 and TTR.

CONCLUSION

Our explorative results confirm our hypothesis that factors in serum from patients with CD change the protein expression pattern of human immortalized osteoblast like cells. We suggest, that these short time changes indeed influence factors of bone metabolism.

Use of dual energy X-ray absorptiometry in pediatric patients

Dual Energy X-ray Absorptiometry (DXA) is a vital tool for assessing bone health in patients at risk for fragility fractures. In pediatric patients, this technology is used in conjunction with clinical fracture history to diagnosis osteoporosis and monitor treatment response. Childhood and adolescence is characterized by linear growth and bone mass accrual; thus there are important differences in the interpretation of bone measurements obtained by DXA in these young patients. This review aims to explore the current indications for DXA use and interpretation of DXA in the pediatric age group using currently available reference databases. Limitations of DXA in pediatric patients, specifically in children with short stature, will be explored. We will review several pathophysiologic mechanisms that may lead to low bone density in children, discussing representative diseases and the recommendations for monitoring bone health with DXA in these conditions. Finally, we will highlight new methods by which DXA imaging can gather additional information on bone health in children and may improve our ability to predict fractures and osteoporosis.

Novel Biomarkers and the Future Potential of Biomarkers in Inflammatory Bowel Disease

There is increasing importance placed upon noninvasive assessment of gut inflammation. These tools are likely to be the key in differentiating intestinal inflammatory disease from functional disorders and in monitoring the response to intervention in individuals with known inflammatory conditions. Although various noninvasive markers are currently available, they have limitations and do not provide ideal utility. This review focuses on emerging markers of gut inflammation, highlighting the potential of specific markers.

Relationships of OPG Genetic Polymorphisms with Susceptibility to Cardiovascular Disease: A Meta-Analysis

Background

The aim of this meta-analysis was to determine whether genetic polymorphisms in the osteoprotegerin (OPG) gene contribute to increased risk of cardiovascular disease (CVD).

Material/Methods

Electronic databases were searched carefully without any language restriction. Analyses of data were conducted using STATA software. Odds ratios (OR) and 95% confidence intervals (95%CI) were also calculated.

Results

Seven clinical case-control studies that enrolled 1170 CVD patients and 1194 healthy subjects were included. The results indicated that OPG gene polymorphism might be closely associated with susceptibility to CVD, especially for rs2073617 T>C and rs2073618 G>C polymorphisms. Ethnicity-stratified analysis indicated that genetic polymorphism in the OPG were closely related with the pathogenesis of CVD among Asians (all P<0.001), but no obvious relationship was found among Caucasians (all P>0.05).

Conclusions

Our meta-analysis provided quantitative evidence that OPG gene polymorphism may be closely related to an increased risk of CVD, especially for rs2073617 T>C and rs2073618 G>C polymorphisms.

Risk factors for osteoporosis in inflammatory bowel disease patients

Inflammatory bowel disease (IBD) patients exhibit higher risk for bone loss than the general population. The chronic inflammation causes a reduction in bone mineral density (BMD), which leads to osteopenia and osteoporosis. This article reviewed each risk factor for osteoporosis in IBD patients. Inflammation is one of the factors that contribute to osteoporosis in IBD patients, and the main system that is involved in bone loss is likely RANK/RANKL/osteoprotegerin. Smoking is a risk factor for bone loss and fractures, and many mechanisms have been proposed to explain this loss. Body composition also interferes in bone metabolism and increasing muscle mass may positively affect BMD. IBD patients frequently use corticosteroids, which stimulates osteoclastogenesis. IBD patients are also associated with vitamin D deficiency, which contributes to bone loss. However, infliximab therapy is associated with improvements in bone metabolism, but it is not clear whether the effects are because of inflammation improvement or infliximab use. Ulcerative colitis patients with proctocolectomy and ileal pouches and Crohn’s disease patients with ostomy are also at risk for bone loss, and these patients should be closely monitored.

TNFRSF11B gene polymorphisms increased risk of peripheral arterial occlusive disease and critical limb ischemia in patients with type 2 diabetes

AIMS

Osteoprotegerin (OPG) is a secretory glycoprotein that belongs to the tumor necrosis factor receptor family and plays a role in atherosclerosis. OPG has been hypothesized to modulate vascular functions; however, its role in mediating atherosclerosis is controversial. Epidemiological data in patients with cardiovascular disease (CVD) indicate that OPG serum levels are associated with several inflammatory markers, myocardial infarction events, and calcium scores, suggesting that OPG may be causative for CVD.

METHODS

The present study aimed to evaluate whether the OPG gene (TNFRSF11B) polymorphisms are involved in the development of peripheral arterial occlusive disease (PAOD) and critical limb ischemia (CLI) in patients with type 2 diabetes. This genetic association study included 402 diabetic patients (139 males and 263 females) with peripheral arterial occlusive disease and 567 diabetic subjects without peripheral arterial occlusive disease (208 males and 359 females). The T245G, T950C, and G1181C polymorphisms of the OPG gene were analyzed by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

We found that the T245G, T950C, and G1181C gene polymorphisms of the OPG gene were significantly (27.9 vs. 12.2 %, P < 0.01; 33.6 vs. 10.4 %, P < 0.01 and 24.4 vs. 12.7 %, P < 0.01, respectively) and independently (adjusted OR 4.97 (3.12-6.91), OR 7.02 (4.96-11.67), and OR 2.85 (1.95-4.02), respectively) associated with PAOD. We also found that these three polymorphisms act synergistically in patients with PAOD and are associated with different levels of risk for PAOD and CLI, depending on the number of high-risk genotypes carried concomitantly by a given individual.

CONCLUSION

The TNFRSF11B gene polymorphisms under study are associated with PAOD, and synergistic effects between these genotypes might be potential markers for the presence and severity of atherosclerotic disorders.

Treatment of bone loss in osteopenic patients with Crohn's disease: a double-blind, randomised trial of oral risedronate 35 mg once weekly or placebo, concomitant with calcium and vitamin D supplementation

OBJECTIVE

Osteoporosis and fractures are frequently encountered in patients with Crohn's disease. In order to prevent fractures, treatment with bone protecting drugs appears warranted early in the course of bone disease when bone loss is not yet prominent. We therefore aimed to demonstrate a beneficial effect on bone density of the bisphosphonate risedronate in osteopenic Crohn's disease patients.

METHODS

This double-blind, placebo-controlled randomised trial of risedronate with calcium and vitamin D supplementation was performed in osteopenic Crohn's disease patients. Patients were treated for 2 years with follow-up after 3 and after every 6 months. Disease characteristics and activity and bone turnover markers were assessed at all visits; dual x-ray absorptiometry was performed at baseline, 12 and 24 months; radiographs of the spine at baseline and 24 months.

RESULTS

Of 132 consenting patients, 131 were randomised (67 placebo and 64 risedronate). Patient characteristics were similar in both groups, although the risedronate group was slightly heavier (body mass index 24.3 vs 23.0 kg/m(2)). Bone mineral density at lumbar spine increased 0.04 g/cm(2) on average in the risedronate group versus 0.01 g/cm(2) in the placebo group (p=0.007). The mean increase in total hip bone mineral density was 0.03 versus 0.01 g/cm(2), respectively (p=0.071). Fracture prevalence and incidence were similar. Change of T-scores and concentrations of bone turnover markers were consistent with a beneficial effect of risedronate when compared with placebo. The effect of risedronate was primarily demonstrated in the first 12 months of treatment. No serious unexpected suspected adverse events were observed.

CONCLUSIONS

A 24-month treatment course with risedronate 35 mg once weekly, concomitant with calcium and vitamin D supplementation, in osteopenic Crohn's disease patients improved bone density at lumbar spine. NTR 163 Dutch Trial Register.

The association between systemic sclerosis and bone mineral density- a meta-analysis of observational studies

Previous research has shown inconsistent effect of systemic sclerosis (SSc) on bone mineral density (BMD). The objective of this study was to perform a meta-analysis of previous articles to investigate the differences in BMD (g/cm(2) ) between SSc and non-SSc populations and to discuss potential underlying mechanisms. Twelve full-text articles (including an outlier study and two studies with identical data) with 662 SSc patients and 886 controls were identified by searching Medline prior to 10 September, 2013 using search terms 'Systemic sclerosis' OR 'scleroderma' and 'osteoporosis' OR 'bone density' OR 'bone mass'. BMD (mean and standard deviation), T-scores and Z-scores at lumbar spine, femoral neck and total hip measured by dual-energy X-ray absorptiometry were extracted. Meta-analysis showed that a lower level of BMD was found in SSc patients, with weighted mean difference of -0.343 (95% CI: -0.500 to -0.186) at femoral neck, -0.084 (95% CI: -0.110 to -0.057) at total hip and -0.104 (95% CI: -0.135 to -0.073) at the lumbar spine. We conclude that patients with SSc may have a lower BMD level than healthy controls.

Association between osteoprotegerin gene polymorphisms and cardiovascular disease in type 2 diabetic patients

Osteoprotegerin (OPG) gene polymorphisms (T245G, T950C and G1181C) have been associated with osteoporosis and early predictors of cardiovascular disease. The aim of this study was to evaluate whether these polymorphisms contribute to cardiovascular disease (CVD) in type 2 diabetic patients. We performed a case-control study with 178 CVD subjects with diabetes and 312 diabetic patients without CVD to assess the impact of variants of the OPG gene on the risk of CVD. The OPG gene polymorphisms were analyzed by using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). There was no significant association between the T245G and G1181C polymorphisms and CVD in the additive genetic model (OR = 0.96, 95% CI 0.64–1.45, p = 0.79; OR = 1.06, 95% CI 0.81–1.39, p = 0.65, respectively). However, the C allele of the T950C polymorphism was independently associated with a risk of CVD in type 2 diabetic patients in this genetic model (OR = 1.38, 95% CI 1.07–1.80, p = 0.01). This study provides evidence that the C allele of the T950C polymorphism is associated with increased risk of CVD in diabetic patients. However, well-designed prospective studies with a larger sample size are needed to validate these results.

Age-of-onset-dependent influence of NOD2 gene variants on disease behaviour and treatment in Crohn's disease

Background

Influence of genetic variants in the NOD2 gene may play a more important role in disease activity, behaviour and treatment of pediatric- than adult-onset Crohn’s disease (CD).

Methods

85 pediatric- and 117 adult-onset CD patients were tested for the three main NOD2 CD-associated variants (p.R702W, p.G908R and p.10007fs) and clinical data of at least two years of follow-up were compared regarding disease behaviour and activity, response to therapy and bone mineral density (BMD).

Results

Chronic active and moderate to severe course of CD is associated in patients with pediatric-onset (p=0.0001) and NOD2 variant alleles (p=0.0001). In pediatric-onset CD the average PCDAI-Score was significantly higher in patients carrying NOD2 variants (p=0.0008). In addition, underweight during course of the disease (p=0.012) was associated with NOD2 variants. Interestingly, osteoporosis was found more frequently in patients carrying NOD2 variant alleles (p=0.033), especially in pediatric-onset CD patients with homozygous NOD2 variants (p=0.037). Accordingly, low BMD in pediatric-onset CD is associated with a higher PCDAI (p=0.0092), chronic active disease (p=0.0148), underweight at diagnosis (p=0.0271) and during follow-up (p=0.0109). Furthermore, pediatric-onset CD patients with NOD2 variants are more frequently steroid-dependent or refractory (p=0.048) and need long-term immunosuppressive therapy (p=0.0213).

Conclusions

These data suggests that the presence of any of the main NOD2 variants in CD is associated with osteoporosis and an age of onset dependent influence towards underweight, higher disease activity and a more intensive immunosuppressive therapy. This observation supports the idea for an early intensive treatment strategy in children and adolescent CD patients with NOD2 gene variants.

Risk factors for osteoporosis in Crohn's disease: infliximab, corticosteroids, body mass index, and age of onset

BACKGROUND

We analyzed the characteristics associated with increased risk of osteoporosis in patients with Crohn's disease in Malta.

METHOD

Eighty-three patients with histologically and endoscopically confirmed Crohn's disease underwent a DEXA bone density scan and their phenotypic characteristics were analyzed.

RESULTS

There was a significant association between body mass index and bone mineral density (P = 0.004) and a significant difference in the T scores of patients according to age at diagnosis (Montreal Classification: P = 0.0006) with patients diagnosed <17 years (n = 13) having lower T scores than those diagnosed at older age groups (n = 70). There was a significant difference between the T scores of patients on infliximab (n = 33) and those not on biological therapy (n = 50, P = 0.0058). Patients with high cumulative corticosteroid doses (>10 mg/d for >3 mo, n = 18) had lower bone mineral densities than patients who received smaller corticosteroid doses (P = 0.013). There was however no significant difference in the T scores of patients according to disease location (P = 0.18), disease type (P = 0.64), gender (P = 0.30), and history of ileal resection (P = 0.68). There was also no significant correlation between disease duration and T scores (hip) (P = 0.61).

CONCLUSIONS

Low body mass index, early disease onset, high corticosteroid doses and, anti-tumor necrosis factor α therapy are associated with increased risk of osteoporosis. Lower T scores in patients on infliximab occur as patients receiving this therapy have more severe inflammation, which is associated with elevated osteoclastogenic factors, rather than as a side-effect of the anti-tumor necrosis factor-α therapy.

Flavonoid intake and bone health

Flavonoids, found in a wide diversity of plant foods from fruits and vegetables, herbs and spices, essential oils, and beverages, have the most potential of dietary components for promotion of bone health beyond calcium and vitamin D. Recent epidemiological studies show flavonoid consumption to have a stronger association with bone than general fruit and vegetable consumption. Bioactive flavonoids are being assessed for properties beyond their chemical antioxidant capacity, including anti-inflammatory actions. Some have been reported to enhance bone formation and to inhibit bone resorption through their action on cell signaling pathways that influence osteoblast and osteoclast differentiation. Future research is needed to determine which of the flavonoids and their metabolites are most effective and at what dose, as well as the mechanism of modulating cellular events, in order to set priorities for clinical trials.

Risedronate improves bone mineral density in Crohn's disease: a two year randomized controlled clinical trial

BACKGROUND

Patients with Crohn's disease have an increased frequency of osteopenia and osteoporosis. This randomized, controlled, double-blind study assessed the efficacy of risedronate versus placebo in treating low bone mineral density (BMD) in patients with Crohn's disease.

METHODS

88 Crohn's disease outpatients with BMD T-score<-1.0 by dual-energy X-ray absorptiometry were randomly assigned to one of two treatment groups for the two year study duration: one group received risedronate 35 mg weekly while another received placebo. Both groups received daily calcium (Ca; 500 mg) and vitamin D (D; 400 IU) supplementation. Percent change in BMD relative to baseline was compared between the two therapies at 12 and 24 months.

RESULTS

Using intent-to-treat analysis, at 12 months, risedronate+Ca+D increased BMD, relative to baseline, more than placebo+Ca+D in the femoral trochanter (1.4±3.4% vs -0.1±3.1%; p=0.03) and total hip (1.1±2.7% vs -0.1±2.5%;p=0.04). This trend in greater BMD continued for the 24 month duration of the study. There was no difference between the two treatment groups for changes in spine BMD. Subgroup analysis revealed that risedronate+Ca+D resulted in significantly better improvement in femoral trochanter BMD in non-smokers (p=0.01), males (p=0.01), those with a history of corticosteroid use in the preceding year (p=0.01), and current users of immunosuppressants (p=0.04).

CONCLUSIONS

Risedronate, in addition to daily calcium and vitamin D supplementation, is superior to calcium and vitamin D alone in improving femoral trochanter and total hip BMD in patients with Crohn's disease.

Bones in pediatric Crohn's disease: a review of fracture risk in children and adults

There is evidence to suggest that the inflammation associated with Crohn's disease (CD) impacts the bone health of patients, predisposing them to early onset osteoporosis and increasing their risk of fracture. Fractures have been documented in patients with CD, with a high proportion of these being found during young adulthood, which suggests that these patients are not simply fracturing as a result of the normal aging process but rather due to the presence of CD. In population terms, patients with CD have increased risk of fracture compared with the general population. Studies in children suggest that, irrespective of time on corticosteroid therapy, the underlying systemic inflammation associated with CD is an independent detrimental influence on the bone health of children with CD. This poses the question as to whether the onset of disease in childhood predisposes the individual to increased risk of future fractures later in life, as a result of decreased peak bone mass during the growing years. It is generally believed that dual energy x-ray absorptiometry-assessed areal bone mineral density is a good indicator of fracture risk; however, several studies have shown this may not be the case. New research, utilizing peripheral quantitative computed tomography, which provides a true volumetric assessment of bone, suggests altered bone geometry in patients with CD, which poses a structural threat by being more brittle and susceptible to damage accumulation.

Advances in the understanding of mineral and bone metabolism in inflammatory bowel diseases

Chronic inflammatory disorders such as inflammatory bowel diseases (IBDs) affect bone metabolism and are frequently associated with the presence of osteopenia, osteoporosis, and increased risk of fractures. Although several mechanisms may contribute to skeletal abnormalities in IBD patients, inflammation and inflammatory mediators such as TNF, IL-1β, and IL-6 may be the most critical. It is not clear whether the changes in bone metabolism leading to decreased mineral density are the result of decreased bone formation, increased bone resorption, or both, with varying results reported in experimental models of IBD and in pediatric and adult IBD patients. New data, including our own, challenge the conventional views, and contributes to the unraveling of an increasingly complex network of interactions leading to the inflammation-associated bone loss. Since nutritional interventions (dietary calcium and vitamin D supplementation) are of limited efficacy in IBD patients, understanding the pathophysiology of osteopenia and osteoporosis in Crohn's disease and ulcerative colitis is critical for the correct choice of available treatments or the development of new targeted therapies. In this review, we discuss current concepts explaining the effects of inflammation, inflammatory mediators and their signaling effectors on calcium and phosphate homeostasis, osteoblast and osteoclast function, and the potential limitations of vitamin D used as an immunomodulator and anabolic hormone in IBD.

Clinical relevance of changes in bone metabolism in inflammatory bowel disease

Low bone mineral density is an established, frequent, but often neglected complication in patients with inflammatory bowel disease (IBD). Data regarding the diagnosis, therapy and follow-up of low bone mass in IBD has been partially extrapolated from postmenopausal osteoporosis; however, the pathophysiology of bone loss is altered in young patients with IBD. Fracture, a disabling complication, is the most important clinical outcome of low bone mass. Estimation of fracture risk in IBD is difficult. Numerous risk factors have to be considered, and these factors should be weighed properly to help in the identification of the appropriate patients for screening. In this editorial, the authors aim to highlight the most important clinical aspects of the epidemiology, prevention, diagnosis and treatment of IBD-related bone loss.

High prevalence of reduced bone mineral density in primary HIV-1-infected men

OBJECTIVE

To assess the bone mineral density (BMD) in a cohort of men with primary HIV-1 infection (PHI).

METHODS

Thirty-three men with PHI had a dual-energy X-ray absorptiometry (DXA) of the lumbar spine, femoral neck and total hip. Osteopenia and osteoporosis were defined according to WHO criteria as T-scores between -1 and -2.5 and -2.5 or less, respectively. The association between clinical and laboratory parameters and BMD was investigated using multivariable linear regression analysis.

RESULTS

Mean age was 38 (SD 9) years and mean body mass index (BMI) 22.7 (SD 3.3) kg/m. Twenty-four men (73%) had a negative or indeterminate Western blot, 32 men (97%) were combination antiretroviral therapy-naive. Mean plasma HIV-1 RNA was 5.0 (SD 1.2) log10 copies/ml. Mean lumbar spine T (-0.8, SD 1.3, P = 0.001) and Z-scores (-0.7, SD 1.3, P = 0.004) and femoral neck T-score (-0.5, SD 0.9, P = 0.003) were significantly lower compared to the reference population. 15/33 men (45%) had osteopenia and 2/33 (6%) osteoporosis. Markers of bone turnover did not differ between patients with or without osteopenia/osteoporosis. Age was negatively associated with femoral neck (beta-coefficient = -0.05, P < 0.001) and total hip T-scores (beta = -0.03, P = 0.04). BMI was associated with lumbar spine (beta = 0.3), femoral neck (beta = 0.2) and total hip (beta = 0.2) T-scores (P < 0.001) and thyroid-stimulating hormone (TSH) with lumbar spine (beta = 0.5, P = 0.045) and femoral neck T-scores (beta = 0.4, P = 0.005). Increased plasma viral load was associated with lower total hip T-scores (beta = -0.2, P = 0.02).

CONCLUSIONS

Reduced BMD was prevalent in PHI men and was associated with increased age, lower BMI and TSH levels, and higher levels of HIV-1 viremia.

Serum RANKL, osteoprotegerin (OPG), and RANKL/OPG ratio in nephrotic children

Receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) play key roles in the pathogenesis of glucocorticoid-induced osteoporosis (GIO). The aim of our study was to determine whether the cumulative glucocorticoid dose (CGCS) in children with idiopathic nephrotic syndrome (INS) has any effect on the concentration of serum RANKL and OPG and the RANKL/OPG ratio. The study population consisted of 90 children with INS, aged 3-20 years, who were treated with GCS. These children were divided into two groups according to the CGCS: low (L)<1 g/kg body weight (BW) and high (H)>or=1 g/kg BW, respectively. The control group (C) consisted of 70 healthy children. RANKL concentration was observed to be significantly higher and OPG significantly lower in INS children than in the reference group: 0.21 (range 0.01-1.36) versus 0.15 (0-1.42) pmol/l (p<0.05), respectively, and 3.76 (1.01-7.25) versus 3.92 (2.39-10.23) pmol/l (p<0.05), respectively. The RANKL/OPG ratio was significantly higher in INS children (p<0.01). The concentration of RANKL, similar to the RANKL/OPG ratio, was significantly higher in Group H children than in Group L children: 0.46 (0.02-1.36 ) versus 0.19 (0.01-1.25) (p<0.01) and 0.14 (0.01-0.71) versus 0.05 (0.002-0.37) (p<0.01), respectively. The concentration of OPG was similar in both groups. There was a positive correlation between CGCS and the concentration of sRANKL as well as the RANKL/OPG ratio (in both cases r=0.33, p<0.05). Based on these results, we suggest that long-term exposure to GCS results in a dose-dependent increase in serum RANKL concentration and the RANKL/OPG ratio, but not in the level of serum OPG.