Bone loss in patients with inflammatory bowel disease: cause, detection and treatment.

PURPOSE OF REVIEW: Inflammatory bowel disease (IBD) is associated with bone loss leading to osteoporosis and increased fracture risk. Bone loss is the result of changes in the balanced process of bone remodeling. Immune cells and cytokines play an important role in the process of bone remodeling and it is therefore not surprising that cytokines as observed in IBD are involved in bone pathology. This review discusses the role of cytokines in IBD-associated bone loss, including the consequences for treatment. RECENT FINDINGS: Many studies have been conducted that showed the effect of a single cytokine on bone cells in vitro, including interleukin (IL)-1ß, IL-6, IL-8, IL-12/IL-23, IL-17, IL-18, IL-32 and interferon-γ. Recently new members of the IL-1 family (IL-1F) have been related to IBD but the consequences for bone health remain uncertain. SUMMARY: Overall, patients have to deal with a cocktail of cytokines, present in their serum. The combination of cytokines can affect bone cells differently compared to the effects of a single cytokine. This implicates that treatment, focused on reducing the inflammation could work best for bone health as well. Vitamin D might also play a role in this.

Oncology drugs in the crosshairs of pharmaceutical crime.

Oncology drugs clearly have become a target for pharmaceutical crime. In 2016, falsified oncology drugs ranked fifth in the most commonly falsified drug category among the reports received by the Pharmaceutical Security Institute. Although the prevalence of illicit oncology drugs in the legal supply chains appears to be small, these drugs are difficult to detect, particularly in clinical practice. Forthcoming countermeasures to detect illicit drugs in high-income countries include compulsory antitampering devices and product verification technology for a risk-based selection of medicines. Health-care professionals must implement these new procedures into their workflow and remain vigilant about those medicines that are not selected. Although countermeasures should firmly tighten supply chain security, there are concerns about how quickly pharmaceutical crime will adapt to these protections. Because patients and health-care professionals have shown a lenient attitude towards purchasing medicines from unreliable sources, measures against the highly accessible illegal medicine supply chain remain necessary. To improve detectability in clinical practice, reporting of ineffectiveness and unusual drug effects as adverse events or adverse drug reactions is essential.

Peri-prosthetic tissue cells show osteogenic capacity to differentiate into the osteoblastic lineage.

During the process of aseptic loosening of prostheses, particulate wear debris induces a continuous inflammatory-like response resulting in the formation of a layer of fibrous peri-prosthetic tissue at the bone-prosthesis interface. The current treatment for loosening is revision surgery which is associated with a high-morbidity rate, especially in old patients. Therefore, less invasive alternatives are necessary. One approach could be to re-establish osseointegration of the prosthesis by inducing osteoblast differentiation in the peri-prosthetic tissue. Therefore, the aim of this study was to investigate the capacity of peri-prosthetic tissue cells to differentiate into the osteoblast lineage. Cells isolated from peri-prosthetic tissue samples (n = 22)-obtained during revision surgeries-were cultured under normal and several osteogenic culture conditions. Osteogenic differentiation was assessed by measurement of Alkaline Phosphatse (ALP), mineralization of the matrix and expression of several osteogenic genes. Cells cultured in osteogenic medium showed a significant increase in ALP staining (p = 0.024), mineralization of the matrix (p < 0.001) and ALP gene expression (p = 0.014) compared to normal culture medium. Addition of bone morphogenetic proteins (BMPs), a specific GSK3ß inhibitor (GIN) or a combination of BMP and GIN to osteogenic medium could not increase ALP staining, mineralization, and ALP gene expression. In one donor, addition of GIN was required to induce mineralization of the matrix. Overall, we observed a high-inter-donor variability in response to osteogenic stimuli. In conclusion, peri-prosthetic tissue cells, cultured under osteogenic conditions, can produce alkaline phosphatase and mineralized matrix, and therefore show characteristics of differentiation into the osteoblastic lineage. © 2016 The Authors. Journal of Orthopaedic Research published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1732-1742, 2017.

Innate immune response and implant loosening: Interferon gamma is inversely associated with early migration of total knee prostheses.

To allow prediction of the risk of loosening prior to surgery, we investigated the relationship between innate immune cytokine response via TLR2 stimulation and early migration of six different knee prostheses using RSA (radiostereometry). This study included 114 patients of a prospective RSA-cohort who received a total knee arthroplasty. Whole blood cytokine responses were obtained by ex vivo stimulation with tripalmitoyl-S-glycerylcysteine (Pam3Cys-SK4) for assessment of the TLR2 immune response. Early migration was calculated using the maximum total point motion (MTPM) 1 year post surgery. Principal component analysis (PCA) was applied to the cytokine data to reduce the correlated data of individual cytokines and identified two components. Subsequently, linear mixed model analyses were applied with adjustments for gender, age, BMI, time-to-blood sampling, and prosthesis type. Component 1, consisting of IFNγ, IL-12p40, IL-10, IL-1ß, TNFα, and IL-6, showed a significant inverse association (ß = -0.128; p = 0.041) with MTPM. Further analysis showed that IFNγ (ß = -0.161, p = 0.008) had the highest contribution to this association and is particularly found in patients receiving another prosthesis than Nexgen (ß = -0.239; p < 0.001). In conclusion, patients with high levels of IFNγ upon stimulation of TLR2 are at lower risk of early migration of their knee prosthesis.

Inhibition of GSK3ß Stimulates BMP Signaling and Decreases SOST Expression Which Results in Enhanced Osteoblast Differentiation.

Both bone morphogenetic protein (BMP) and Wnt signaling have significant roles in osteoblast differentiation and the interaction between BMP and Wnt signaling is well known. Sclerostin is an important inhibitor of bone formation, inhibiting Wnt signaling and downstream effects of BMP such as alkaline phosphatase activity and matrix mineralization in vitro. However, little is known about the effect of BMP and Wnt signaling interaction on the regulation of SOST, the gene encoding sclerostin. Possibly, uncoupling of osteoblast differentiation regulators and SOST expression could increase osteoblast differentiation. Therefore, we investigated the effect of BMP and Wnt signaling interaction on the expression of SOST and the subsequent effect on osteoblast differentiation. Human osteosarcoma cells (SaOS-2) and murine pre-osteoblast cells (KS483) were treated with different concentrations of Wnt3a, a specific GSK3ß inhibitor (GIN) and BMP4. Both Wnt3a and GIN increased BMP4-induced BMP signaling and BMP4 increased Wnt3a and GIN-induced Wnt signaling. However, the effect of GIN was much stronger. Quantitative RT-PCR analysis showed that SOST expression dose-dependently decreased with increasing Wnt signaling, while BMP4 induced SOST expression. GIN significantly decreased the BMP4-induced SOST expression. This resulted in an increased osteoblast differentiation as measured by ALP activity in the medium and matrix mineralization. We conclude that GSK3ß inhibition by GIN caused an uncoupling of BMP signaling and SOST expression, resulting in an increased BMP4-induced osteoblast differentiation. This effect can possibly be used in clinical practice to induce local bone formation, for example, fracture healing or osseointegration of implants.

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.

Bone cells from patients with quiescent Crohn's disease show a reduced growth potential and an impeded maturation.

Patients with Crohn's disease (CD) are at increased risk of developing osteoporosis. The mechanism underlying bone loss in CD patients is only partly understood. Inflammation is thought to contribute by causing a disturbed bone remodeling. In this study, we aimed to compare functional characteristics of osteoblasts from CD patients and controls, as osteoblasts are one of the effector cells in bone remodeling. The study included 18 patients with quiescent CD and 18 healthy controls. Bone cells obtained from iliac crest biopsies were cultured in the absence and presence of the inflammatory cytokines IL-1α, IL-1ß, IL-6, TNF-α, IL-10, and TGF-ß. At various time points, cell proliferation and differentiation were analyzed. Bone cells from CD patients showed a prolonged culture period to reach confluence and a decreased cell number at confluence. CD patient-derived bone cell cultures produced higher alkaline phosphatase levels, whereas osteocalcin levels were considerably reduced compared to control cultures. At the proliferation level, the responsiveness to inflammatory cytokines was similar in bone cells from CD patients and controls. At the differentiation level, CD cultures showed an increased responsiveness to IL-6 and a decreased responsiveness to TGF-ß. Responsiveness to the other cytokines tested was unaffected. In summary, we show a reduced growth potential and impeded maturation of bone cells from quiescent CD patients in vitro. These disease-related alterations combined with an unchanged sensitivity of CD patient-derived bone cells to inflammatory cytokines, provide a new insight in the understanding of CD-associated bone loss.

T cell-mediated increased osteoclast formation from peripheral blood as a mechanism for Crohn's disease-associated bone loss.

The pathophysiology of osteoporosis in patients with Crohn's disease (CD) is still not completely elucidated. In this study, we evaluated osteoclastogenesis from peripheral blood cells of CD patients and studied the role of lymphocytes and inflammatory cytokines in this process. Peripheral blood mononuclear cells from seven patients with quiescent CD and matched healthy controls were isolated, and separated into T cells, B cells, and a T- and B-cell depleted fraction. In various culture combinations, osteoclast formation in the absence of the osteoclastogenic factors RANKL and M-CSF was assessed by scoring the number of tartrate-resistant acid phosphatase (TRACP) positive multinucleated cells (MNCs). Cytokine levels in culture supernatants were measured. Formation of heterogeneous cell clusters in culture was noticed; a process that was inhibited by anti-LFA-1. In CD cultures, mean cluster area was up to threefold higher than in control cultures, and shown to be induced by T cells. Over tenfold higher numbers of TRACP(+) MNCs were found in CD cultures, but exclusively in cultures containing T cells. Formation of cell clusters correlated strongly with formation of TRACP(+) MNCs. Both cell cluster formation and osteoclast formation were related to IL-17 levels in vitro. In conclusion, osteoclastogenesis, preceded by cell cluster formation, is T cell-mediated and increased in patients with quiescent CD. Our findings suggest heterotypic interactions between osteoclast precursors and T cells to be a triggering step in osteoclast formation in CD. Furthermore, our results propose a possible role for IL-17 in osteoclastogenesis in CD patients, and as such in CD-associated bone loss.

Histomorphometric analysis reveals reduced bone mass and bone formation in patients with quiescent Crohn's disease.

BACKGROUND & AIMS: Crohn's disease (CD) is associated with an increased prevalence of osteoporosis, but the pathogenesis of this bone loss is only partly understood. We assessed bone structure and remodeling at the tissue level in patients with quiescent CD. We also investigated the roles of osteocyte density and apoptosis in CD-associated bone loss. METHODS: The study included 23 patients with quiescent CD; this was a subgroup of patients from a large randomized, double-blind, placebo-controlled, multicenter trial. We obtained transiliac bone biopsy samples and performed histomorphometric analysis. Results were compared with data from age- and sex-matched healthy individuals (controls). RESULTS: Trabecular bone volume was decreased among patients with CD compared with controls (18.90% vs 25.49%; P < .001). The low bone volume was characterized by decreased trabecular thickness (120.61 vs 151.42 µm; P < .01). Bone formation and resorption were reduced, as indicated by a decreased mineral apposition rate (0.671 vs 0.746 µm/day; P < .01) and a low osteoclast number and surface area compared with controls and published values, respectively. In trabecular bone of patients with CD, osteocyte density and apoptosis were normal. The percentage of empty lacunae among patients was higher than that of published values in controls. CONCLUSIONS: In adult patients with quiescent CD, bone histomorphometric analysis revealed a reduction in bone mass that was characterized by trabecular thinning. The CD-associated bone loss was caused by reduced bone formation, possibly as a consequence of decreased osteocyte viability in the patients' past.