Early supplemental α2-macroglobulin attenuates cartilage and bone damage by inhibiting inflammation in collagen II-induced arthritis model.

OBJECTIVE: To determine if early supplemental intra-articular α2-macroglobulin (A2M) has a chondroprotective effect in a collagen II-induced arthritis (CIA) mice model. METHODS: DBA/1 mice were randomized into four groups (n = 15/group): (a) CIA + 1.2 µg of A2M; (b) CIA + 0.8 µg of A2M; (c) CIA + 0.4 µg of A2M; (d) vehicle + phosphate-buffered saline (PBS). A2M was injected into right ankles and PBS was injected into the left ankles simultaneously as internal control at days 36, 43 and 50. The CIA inflammation clinical score and ankle thickness were recorded every other day starting on day 21 until sacrifice. Changes in inflammation were monitored by in vivo fluorescence molecular tomography (FMT). Inflammation, cartilage and bone damage were assessed with X-ray, histology and immunohistochemistry. Cartilage and inflammation-related gene expression was quantified by real-time polymerase chain reaction (PCR). RESULTS: All mice showed ankle inflammation on day 33. After day 43, lower clinical scores, ankle thickness and Sharp/van der Heijde method scores in A2M-treated ankles compared with PBS-treated ankles. FMT data indicated that the inflammation markers MMPSense and ProSense were significantly elevated in the PBS-treated ankles than A2M-treated ankles. Histology and X-ray analyses indicated that A2M administration resulted in lower levels of inflammatory infiltration and synovial hyperplasia, as well as more typical cartilage and bone organization with increased COL II and Aggrecan staining when compared with PBS-treated ankles. In addition, real-time PCR showed that,matrix metalloproteinase-3, -9, -13, COL X and Runx2 were significantly less expressed in A2M-treated groups than PBS-treated animals. CONCLUSION: Early supplemental intra-articular A2M exerts an anti-inflammatory effect and attenuates cartilage and bone damage in a CIA model.

Dual-energy computed tomography for monitoring the effect of urate-lowering therapy in gouty arthritis.

OBJECTIVE: To investigate the relationships between changes in serum urate levels and dual-energy computed tomography (DE-CT) results during urate-lowering therapy (ULT) and to investigate the effects of treatment duration and drugs on changes in DE-CT results. METHODS: Forty-four patients diagnosed with gout were enrolled in this investigation. DE-CT was conducted on the foot at baseline and the end of follow-up (6-24 months). Crystals were classified as: (i) L, number of large crystals with diameter ≥ 3 mm; (ii) S, number of small crystals with diameter < 3 mm; (iii) T, total number of crystals; and (iv) Vmax, volume of the maximal crystal. RESULTS: Number of urate crystals (L, S as well as T) and Vmax decreased significantly through ULT. Significant decrease of urate crystal numbers and/or Vmax was observed in different follow-up groups, and the decrease in serum urate levels was positively related to the decrease of T (r = 0.43, P = 0.04) and Vmax (r = 0.63, P = 0.04). Moreover, analysis of covariance results demonstrated significant effects of treatment duration and serum urate levels on results of DE-CT. CONCLUSION: Both urate crystal numbers and Vmax decreased significantly during ULT. Additionally, ULT duration and serum urate levels had significant effects on the decrease of Vmax and number of large crystals measured by DE-CT.

Effects of alendronate and pamidronate on cultured rat metatarsal bones: failure to prevent dexamethasone-induced growth retardation.

Bisphosphonates are widely used anti-resorptive drugs in the adult population. In children, their use has mainly been limited to patients with osteogenesis imperfecta. However, the powerful effects of bisphosphonates on bone turnover have raised concern about their long-term effects on the growing skeleton. We aimed to study the effects of two commonly used bisphosphonates, alendronate (Aln) and pamidronate (Pam) on normal bone growth as well as their potential to prevent glucocorticoid-induced growth retardation. Effects on bone growth were studied in fetal rat metatarsal bones (day E20) that were cultured for 5-47 days and measured every 2-7 days. Cellular mechanisms were investigated in metatarsal bones and also in the human chondrocytic cell line HCS-2/8. Chondrocyte viability (WST-1), proliferation (BrdU incorporation), differentiation (collagen type X immunohistochemistry) and apoptosis (TUNEL and Cell Death ELISA) were determined. At a clinically relevant concentration of bisphosphonates (1 microM), metatarsal bone growth was stimulated by both Aln (p<0.001 for length and p<0.05 for width) and Pam (p<0.05 for both length and width) from day 19 of culture. The growth-stimulatory effect was associated with increased chondrocyte proliferation (+21% with Aln and +24% with Pam), while cell differentiation and apoptosis were not affected. Despite the finding that both Aln and Pam (1 muM) rescued HCS-2/8 cells from undergoing dexamethasone-induced apoptosis, neither of them was able to prevent dexamethasone-induced growth retardation of fetal rat metatarsal bones. Aln and Pam have the capacity to stimulate the growth of cultured fetal rat metatarsal bones; an effect associated with increased proliferation of growth plate chondrocytes. Our experimental data suggest that bisphosphonates are ineffective in preventing glucocorticoid-induced growth retardation. Nevertheless, based on our in vitro data, both Aln and Pam appear safe to use in growing children, at least with regard to their effects on linear bone growth.

A selective p38 alpha mitogen-activated protein kinase inhibitor reverses cartilage and bone destruction in mice with collagen-induced arthritis.

Destruction of cartilage and bone is a poorly managed hallmark of human rheumatoid arthritis (RA). p38 Mitogen-activated protein kinase (MAPK) has been shown to regulate key proinflammatory pathways in RA, including tumor necrosis factor alpha, interleukin (IL)-1beta, and cyclooxygenase-2, as well as the process of osteoclast differentiation. Therefore, we evaluated whether a p38alpha MAPK inhibitor, indole-5-carboxamide (SD-282), could modulate cartilage and bone destruction in a mouse model of RA induced with bovine type II collagen [collagen-induced arthritis (CIA)]. In mice with early disease, SD-282 treatment significantly improved clinical severity scores, reduced bone and cartilage loss, and reduced mRNA levels of proinflammatory genes in paw tissue, including IL-1beta, IL-6, and cyclooxygenase-2. Notably, SD-282 treatment of mice with advanced disease resulted in significant improvement in clinical severity scoring and paw swelling, a reversal in bone and cartilage destruction as assessed by histology, bone volume fraction and thickness, and three-dimensional image analysis. These changes were accompanied by reduced osteoclast number and lowered levels of serum cartilage oligomeric matrix protein, a marker of cartilage breakdown. Thus, in a model of experimental arthritis associated with significant osteolysis, p38alpha MAPK inhibition not only attenuates disease progression but also reverses cartilage and bone destruction in mice with advanced CIA disease.