Modified Scarf Osteotomy with Medial Capsular Interposition Combined with Metatarsal Shortening Offset Osteotomy: A Comparison of Patients with Noninflammatory Arthritis and Rheumatoid Arthritis of the Foot

BACKGROUND

Patients who have noninflammatory arthritis of the feet may develop destructive changes on the first metatarsal head and painful dislocation of the metatarsophalangeal (MTP) joint of 1 or more lesser toes. This aim of this study was to compare feet with noninflammatory arthritis and those with rheumatoid arthritis (RA) with respect to the clinical and radiographic outcomes after treatment of these destructive deformities with a modified Scarf osteotomy with medial capsular interposition into the newly formed first MTP joint, combined with metatarsal shortening offset osteotomy.

METHODS

A retrospective observational study of 93 feet (31 with noninflammatory arthritis and 62 with RA) was performed. Hallux and lesser-toe scores on the Japanese Society for Surgery of the Foot (JSSF) scoring system, a self-administered foot evaluation questionnaire (SAFE-Q), and preoperative and postoperative radiographic parameters were evaluated.

RESULTS

There were significant improvements at the time of the final follow-up in the mean scores on the hallux and lesser-toe scales of the JSSF system and in the SAFE-Q score. The postoperative JSSF lesser-toes function score was better for the feet with noninflammatory arthritis feet than the feet with RA. There was no significant difference in the hallux valgus angle (HVA) between 1 month postoperatively and the final follow-up for both groups. Furthermore, the HVA showed a strong correlation between the 1-month and final follow-up values.

CONCLUSIONS

The combination of the modified Scarf osteotomy with medial capsular interposition and shortening metatarsal offset osteotomy was useful and safe in feet with noninflammatory arthritis. The HVA at 1 month after surgery is useful to predict the HVA within 5 years after surgery. The postoperative clinical score for the lesser toes was better in the feet with noninflammatory arthritis.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Modified Scarf Osteotomy with Medial Capsular Interposition in Great Toe and Metatarsal Shortening Offset Osteotomy in Lesser Toes for Rheumatoid Deformity

Introduction

Modified Scarf osteotomy combined with metatarsal shortening offset osteotomy of the lesser toes provides stable forefoot realignment with preservation of the motion of the first metatarsophalangeal (MTP) joint.

Indications & Contraindications

Step 1: Preoperative Planning

On a standing anteroposterior radiograph, plan the resection of the first metatarsal as the amount equal to the overlap of the first metatarsal and the base of the proximal phalanx, and plan to resect enough length of the lesser metatarsals to allow reduction of the MTP joints while keeping these metatarsals longer than the first.

Step 2: Operating Room Setup (Fig.2)

With the patient supine, and a fluoroscope in place to later check alignment and correction, ensure that full knee joint flexion is possible so that the foot can be placed parallel to the operating table.

Step 3: Incisions (Fig. 3)

Make the incisions.

Step 4: Approach

Approach the lesser toes through the lateral 2 dorsal toe incisions and the great toe through the dorsal first web space incision.

Step 5: Osteotomy and Reduction

Resect a sufficient amount of each lesser metatarsal neck to allow reduction of the respective MTP joint (Fig. 5-A); to correct the hallux valgus deformity, perform sufficient shortening and translation of the first metatarsal shaft through a horizontal longitudinal osteotomy (Fig. 5-B).

Step 6: Fixation

Lock the distal fragment (metatarsal head) of the lesser metatarsals into 3-mm-deep grooves in the cortical bone of the proximal fragment and then secure it to the proximal fragment with a 1.2-mm Kirschner wire (Fig. 6-A); shift the distal bone fragment of the first metatarsal laterally and securely fix it with screws (Fig. 6-B).

Step 7: Medial Capsular Interposition and Closure

After correction of the hallux valgus deformity using the modified Scarf osteotomy, interpose the 10-mm-wide capsular flap into the first MTP joint (Fig. 7).

Results

In our series of 76 cases in 60 patients, sufficient reduction of the hallux valgus deformity was achieved consistently even in cases with severe destruction (Larsen grade 4 or 5) of the first MTP joint due to rheumatoid arthritis².

Pitfalls & Challenges

Background:

Arthrodesis of the first metatarsophalangeal (MTP) joint has been recommended for severe hallux valgus deformity in patients with rheumatoid arthritis. We developed an alternative procedure that preserves motion of the first MTP joint while restoring alignment and balance to the forefoot. This procedure was shown to be effective in a series of 60 patients with a 3-year follow-up.

Description:

We perform a modified Scarf osteotomy, with the longitudinal first metatarsal cut parallel to the sole of the foot and with shortening of the metatarsal to realign the first ray. This is combined with an interpositional capsular arthroplasty of the first MTP joint and shortening offset osteotomies of the lesser metatarsals.

Alternatives:

Alternatives include arthrodesis of the first MTP joint combined with resection arthroplasty of the lesser MTP joints, or of all 5 MTP joints, or perhaps interpositional (total) joint arthroplasty for severe rheumatoid forefoot deformity/destruction.

Rationale:

The purpose of the modified Scarf osteotomy is preservation of motion of the first MTP joint and protection against destruction of the rheumatoid joint. The metatarsal shortening offset osteotomy provides rigid stabilization at the site of osteotomy after dynamic correction to make the transverse arch.

Modified Scarf Osteotomy with Medial Capsule Interposition for Hallux Valgus in Rheumatoid Arthritis: A Study of Cases Including Severe First Metatarsophalangeal Joint Destruction

BACKGROUND

Arthrodesis of the first metatarsophalangeal (MTP) joint has been recommended for severe hallux valgus deformity in patients with rheumatoid arthritis (RA). However, with the progress of medical treatment of RA, joint preservation surgery has recently been performed. The aim of this study was to investigate the clinical and radiographic outcomes of modified Scarf osteotomy with medial capsule interposition for RA cases including severe destruction of the first MTP joint and to evaluate risk factors for recurrence.

METHODS

A retrospective observational study of 76 cases (60 patients) followed for a mean of 35.3 months (range, 24 to 56 months) after a modified Scarf osteotomy was performed. Scores on the Japanese Society for Surgery of the Foot (JSSF) RA foot and ankle scale, the JSSF hallux scale, and a self-administered foot evaluation questionnaire (SAFE-Q) were determined along with preoperative and postoperative radiographic parameters.

RESULTS

There was a significant improvement, from preoperatively to final follow-up, in the mean JSSF RA foot and ankle score (from 52.2 to 76.9 points) and the mean JSSF hallux score (from 38.2 to 74.5 points). There was a recurrence (hallux valgus angle [HVA] of >20°) in 12 feet (16%). The preoperative DAS28-CRP score (disease activity score [based on 28 joints in the body]-C-reactive protein score) and intermetatarsal angles between the first and second metatarsals (M1M2A) and between the first and fifth metatarsals (M1M5A) were significantly greater in the recurrence group, as were the HVA, M1M2A, M1M5A, and Hardy grade at 3 months after surgery. There was a significant negative correlation between the preoperative DAS28-CRP score and the JSSF RA foot and ankle score at final follow-up (β = -0.39, p = 0.02) and a significant positive correlation between the preoperative DAS28-CRP score and the HVA at final follow-up (β = 0.44, p = 0.001).

CONCLUSIONS

The modified Scarf osteotomy with medial capsule interposition for hallux valgus deformity improved clinical and radiographic outcomes in RA cases with severe destruction of the first MTP joint. Increased preoperative M1M2A and M1M5A; incomplete reduction of the sesamoid bone; and the HVA, M1M2A, and M1M5A at 3 months after surgery should be evaluated as they are associated with recurrence of the deformity. The preoperative DAS28-CRP score was associated with the clinical and radiographic outcomes after surgery.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Total Ankle Arthroplasty for Rheumatoid Arthritis in Japanese Patients: A Retrospective Study of Intermediate to Long-Term Follow-up

Background:

Outcomes after total ankle arthroplasty (TAA) combined with additive techniques (augmentation of bone strength, control of soft-tissue balance, adjustment of the loading axis) for the treatment of rheumatoid arthritis were evaluated after intermediate to long-term follow-up. The influences of biologic treatment on the outcomes after TAA were also evaluated.

Methods:

We performed a retrospective observational study involving 50 ankles (44 patients) that underwent TAA for the treatment of rheumatoid arthritis. The mean duration of follow-up was 7.1 years. Clinical outcomes were evaluated with use of the Japanese Society for Surgery of the Foot (JSSF) scale score and a postoperative self-administered foot-evaluation questionnaire (SAFE-Q). Radiographic findings were evaluated as well. These parameters also were compared between patients managed with and without biologic treatment.

Results:

This procedure significantly improved the clinical scores of the JSSF rheumatoid arthritis foot and ankle scale (p < 0.0001). Forty-eight of the 50 ankles had no revision TAA surgery. Subsidence of the talar component was seen in 8 ankles (6 in the biologic treatment group and 2 in the non-biologic treatment group); 2 of these ankles (both in the biologic treatment group) underwent revision TAA. The social functioning score of the SAFE-Q scale at the time of the latest follow-up was significantly higher in the biologic treatment group (p = 0.0079). The dosage of prednisolone (p = 0.0003), rate of usage of prednisolone (p = 0.0001), and disease-activity score (p < 0.01) at the time of the latest follow-up were all significantly lower in the biologic treatment group.

Conclusions:

TAA is recommended for the treatment of rheumatoid arthritis if disease control, augmentation of bone strength, control of soft-tissue balance, and adjustment of the loading axis are taken into account. The prevention of talar component subsidence remains a challenge in patients with the combination of subtalar fusion, rheumatoid arthritis, and higher social activity levels.

Level of Evidence:

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Prevalence of gastroesophageal reflux disease symptoms and related factors in patients with rheumatoid arthritis

Gastroesophageal reflux disease (GERD) is common in patients with many chronic diseases, but has not been well recognized in rheumatoid arthritis (RA). We investigated the prevalence of GERD symptoms in 278 outpatients with RA and their association with such clinical factors as age, sex, height, weight, body mass index, medications drugs, and functional status evaluated by the Modified Health Assessment Questionnaire (MHAQ). GERD symptoms were evaluated by Frequency Scale for the Symptoms of GERD (FSSG). The mean FSSG score for all patients was 5.6, and 82 patients were considered to have GERD symptoms (FSSG score ≥8), thus the overall prevalence of GERD symptoms was 29.5%. MHAQ score and height were significantly higher and lower, respectively, and prednisolone usage was significantly more in the patients with GERD symptoms than those without. These three clinical factors were also significantly associated with GERD symptoms by univariate logistic regression. Multivariate logistic regression analysis demonstrated that MHAQ was the only clinical factor related to GERD symptoms. In conclusion, the prevalence of GERD symptoms in RA patients was high and strongly associated with decreased functional status, suggesting that physicians should pay attention to GERD symptoms in RA management, especially for patients with low functional status.

Serum level of oxidative stress marker is dramatically low in patients with rheumatoid arthritis treated with tocilizumab

Regarding the pathobiology of rheumatoid arthritis, oxidative stress induced by reactive oxygen species is an important mechanism that underlies destructive and proliferative synovitis. Abundant amounts of reactive oxygen species have been detected in the synovial fluid of inflamed rheumatoid joints. It is reported that drugs that block tumor necrosis factor-α reduce the oxidative stress marker levels in patients with rheumatoid arthritis. In this study, we measured reactive oxygen species using a free radical analytical system in patients with rheumatoid arthritis treated with disease-modifying antirheumatic drugs, tumor necrosis factor-α-blocking drugs (infliximab, etanercept), and an interleukin-6-blocking drug (tocilizumab). The serum level of oxidative stress was drastically low in patients with rheumatoid arthritis treated with tocilizumab, suggesting that interleukin-6 blocking therapy reduces not only joint damage, but also vascular degeneration in patients with rheumatoid arthritis. We believe that such a drastic effect would reduce the incidence of cardiovascular events and mortality in patients with rheumatoid arthritis.

Hemophagocytic syndrome in a patient with rheumatoid arthritis

A 76-year-old man with rheumatoid arthritis, who had been treated with oral prednisolone and methotrexate, presented with high fever and generalized fatigability. Laboratory data demonstrated marked pancytopenia, which we first regarded as a side effect of methotrexate, and leucovorin was administered with granulocyte-colony stimulating factor and transfusions. Because no recovery was recognized, however, bone marrow aspiration was performed, by which hemophagocytic syndrome was diagnosed. After corticosteroid pulse therapy was initiated, the patient's symptoms were rapidly attenuated and laboratory data rapidly normalized.

[Bone fracture and the healing mechanisms. Metabolic bone disease and skeletal healing]

We described about skeletal healing in metabolic bone diseases. Fracture healing in osteoporosis was not well investigated basically and clinically. Clinical research is difficult because fracture healing is affected by underlined disease causing osteoporosis and medication for osteoporosis. Recent basic research using ovariectomized model revealed delayed callus formation and decreased callus strength. As for osteomalacia, callus formation was delayed, and to correct the calcium and phosphate balance using vitamin D or phosphate improve the fracture healing and mineralization. As for osteopetrosis, fracture healing was delayed, but in most cases healing could be achieved finally non-operatively. Femoral neck fracture and coxa vara deformity should be considered to treat operatively.

Treatment of juxta-articular intraosseous cystic lesions in rheumatoid arthritis patients with interconnected porous calcium hydroxyapatite ceramic

In patients with rheumatoid arthritis (RA), juxta-articular intraosseous cystic lesions may cause spontaneous pathological fractures. The outcome of curettage and the packing of such lesions with interconnected porous calcium hydroxyapatite ceramic (IP-CHA) was investigated. Twelve lesions were treated in ten RA patients (three men and seven women with a mean age of 59 years). Ten lesions were associated with impending pathological fracture involving the articular surface. In all patients, curettage and packing of the bone cavity with IP-CHA were done. Assessment was based on final radiographs obtained an average of 30 months after surgery (range 10-47 months). Absorption of the implanted IP-CHA, expansion of the lesion, implant incorporation into host bone, and postoperative fractures were investigated. At final follow-up, there was no absorption of the implanted IP-CHA in any of the lesions. Expansion of the radiolucent area was only noted in one lesion. Seven of the other 11 lesions showed major incorporation of IP-CHA into host bone, while minor incorporation was seen in four lesions. There were no postoperative fractures. In conclusion, curettage and packing with IP-CHA is a feasible method of preventing pathological fracture due to juxta-articular intraosseous cystic lesions in RA patients.

High oxygen tension prolongs the survival of osteoclast precursors via macrophage colony-stimulating factor

The oxygen tension affects the function, differentiation, and transformation of various cells, including bone cells. In pathological conditions such as rheumatoid arthritis (RA), rapidly destructive arthropathy, and primary or metastatic tumors, severe bone destruction or osteolysis occurs. Abundant blood vessels are often observed around these destructive lesions. At such sites, we have confirmed the increased production of reactive oxygen species (ROS) induced by a high oxygen tension and/or oxidative stress, as well as numerous osteoclasts detectable by immunohistochemistry. These findings suggest that osteoclasts are influenced by the high oxygen tension in pathological bone lesions because the zone around blood vessels has a relatively high oxygen tension. In this study, we investigated the effects of oxygen tension on osteoclastogenesis by culturing human CD14-positive cells (osteoclast precursors) with or without osteoblast-like supporting cells (Saos-4/3 cells) under a normal oxygen tension (20% O(2)) or a high oxygen tension (40% O(2)). A high oxygen tension markedly prolonged the duration of osteoclast precursor formation in the presence of supporting cells, and also markedly and persistently increased the production of macrophage colony stimulating factor (M-CSF) by supporting cells. Furthermore, we found an increase of cells expressing M-CSF and cells positive for tartrate-resistant acid phosphatase (TRAP) in hypervascular destructive bone lesions of RA patients where ROS were also abundant.

Laboratory and febrile features after joint surgery in patients with rheumatoid arthritis treated with tocilizumab

OBJECTIVES

To understand the acute phase responses to surgical intervention in patients with rheumatoid arthritis (RA) treated with the anti-interleukin (IL)6 receptor antibody, tocilizumab.

METHODS

In a retrospective 1:1 pair-matched case-control study, 22 tocilizumab-treated RA cases and 22 cases treated with conventional disease-modifying antirheumatic drugs (DMARDs) and matched for type of surgery, age and sex were evaluated for body temperature every day, and blood C-reactive protein (CRP) levels and white blood cell (WBC), neutrophil and lymphocyte counts on days -1, 1, 3 and weeks 1 and 2 after joint surgery. Safety issues were also monitored.

RESULTS

No complications of infection or delay of wound healing occurred in either patient group. Tocilizumab partially, but significantly, suppressed the increase in body temperature on postoperative days 1 and 2, compared with DMARDs (average (SD) maximum increase in temperature was 0.45 (0.1) degrees C in the tocilizumab group and 0.78 (0.1) degrees C in the DMARD group; p<0.01). Tocilizumab completely suppressed the increase in CRP after surgery, whereas all cases treated with DMARDs showed a significant increase of CRP at postoperative day 1 (5.5 (0.6) mg/dl; p<0.001). WBC, neutrophil and lymphocyte counts showed no remarkable change after surgery, and there was no significant difference in any cell counts between the patient groups.

CONCLUSIONS

Within this small number of cases, safe operations on patients were performed during tocilizumab treatment. Tocilizumab suppressed fever and increase of CRP after surgery, whereas there was no influence on the transition in number of leukocytes. This characteristic postoperative response should be considered during tocilizumab treatment.

Characteristics of fracture and related factors in patients with rheumatoid arthritis

To examine the clinical features of vertebral and non-vertebral fractures in patients with rheumatoid arthritis (RA), including insufficiency fractures, and to assess the risk factors for fracture, we prospectively studied 209 outpatients with rheumatoid arthritis for 1 year. The age, gender, Steinbrocker's functional class, glucocorticoid use, history of lower limb surgery, serum C-reactive protein (CRP), and use of bisphosphonates were evaluated. Examination for fractures was performed by radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scanning. Thirty-three fractures occurred in 24 patients over the 1-year study period, and the incidence was 15.8 fractures per 100 patient-years. Fractures occurred at various sites. The majority (70%) was insufficiency fracture, and more than 50% caused ambulatory dysfunction. Radiographic findings were absent in 39% of the fractures at the onset of pain. The functional class and glucocorticoid dose were significantly associated with fracture development. This prospective study showed that the incidence of fractures, especially insufficiency fractures, was very high in patients with rheumatoid arthritis and that most of their fractures caused gait disturbance. Early intervention to prevent secondary osteoporosis is recommended to maintain the quality of life in patients with rheumatoid arthritis, especially those with functional impairment or undergoing glucocorticoid therapy.

[p38 MAP Kinase inhibitor]

FR167653 is a potent inhibitor of p38 MAP Kinase and inhibits TNF-alpha and IL-1beta production in inflammatory cells. In this study we investigated the effect of FR167653 on CIA. CIA rats were subcutaneously injected with FR167653 (32 mg/kg/day) starting on the day of the booster injection and after the onset of arthritis in the prophylactic and therapeutic treatment groups, respectively. The hind paw swelling, radiolographic and histologic scores, and osteoclast number were evaluated. Serum and tissue cytokine levels were assessed by ELISA. Flow cytometric analysis of T-lymphocytes from bone marrow was also performed. The effect of FR167653 on in vitro osteoclast formation induced by sRANKL and TNF-alpha was examined. Hind paw swelling occurred in CIA rats but not in the prophylactic treatment group. Therapeutic treatment also significantly reduced the paw swelling. The mean radiographic, histologic score, and osteoclast number of the treatment group were significantly lower than those of CIA rats without treatment. FR167653 treatment reduced serum TNF-alpha and IL-1beta levels, ankle IL-1beta concentration, and CD4-CD8a+ T-cell population in bone marrow. Furthermore, FR167653 inhibited the osteoclast-like cell differentiation induced by both sRANKL and TNF-alpha in vitro. FR167653 prevented the onset of arthritis in a prophylactic treatment model and suppresses the progression of joint destruction in a therapeutic treatment model, suggesting that p38 MAP Kinase is a potential therapeutic target for rheumatoid arthritis.

Celecoxib prevents juxta-articular osteopenia and growth plate destruction adjacent to inflamed joints in rats with collagen-induced arthritis

The effect of celecoxib, a selective cyclooxygenase-2 inhibitor, on juxta-articular osteopenia and growth plate destruction adjacent to inflamed joints was investigated in rats with collagen-induced arthritis. Forty rats were assigned to the following six groups: (1) an untreated arthritis group; (2-5) arthritis rats receiving indomethacin (3 mg/kg per day), dexamethasone (0.2 mg/kg per day), or celecoxib (5 or 50 mg/kg per day), and (6) normal control rats. Drugs were administered for 2 weeks from the onset of arthritis. Then the hind paws were measured. Juxta-articular osteopenia and growth plate destruction adjacent to inflamed joints were also assessed using plain radiography, bone mineral density measurement, histology, and histomorphometry. Each treatment reduced inflammation, but only dexamethasone and high-dose celecoxib prevented bone loss adjacent to inflamed joints and significantly decreased bone resorption. In contrast, no treatment affected bone formation parameters. Growth plate destruction adjacent to inflamed joints was prevented by indomethacin, dexamethasone, and high-dose celecoxib. Although dexamethasone abolished inflammation, growth plate destruction was still observed. In conclusion, among the various drugs tested, only celecoxib had a preventive effect on both growth plate destruction and bone loss adjacent to inflamed joints in this arthritis model.

[Clinical features of fracture with glucocorticoid induced osteoporosis and rheumatoid arthritis]

Fracture in patients with glucocorticoid-induced osteoporosis (GIO) is occurred despite properly maintained bone mineral density. So the criteria of primary osteoporosis cannot be adapted to GIO. This is caused by the difference of disease's pathology. In glucocorticoid therapy, duration and total volume of dosage of the drug affects bone strength, and then the risk of fracture will be increasing. However, even if low dosage of glucocorticoid is used for the patients, the risk of fracture has increased more than that of normal people. The site of fracture is well recognized in vertebral body, hip joint, rib, and sacrum. While, the fracture in patients with rheumatoid arthritis (RA), one of the disease representing GIO, is observed in all of the body, including long bone and periarticular bone in addition to the site of fracture observed in GIO. The risk of fracture in patients with RA is increased by the glucocorticoid daily use and the functional disability.

Imatinib mesylate inhibits osteoclastogenesis and joint destruction in rats with collagen-induced arthritis (CIA)

Macrophage colony-stimulating factor (M-CSF) is a key factor for osteoclastogenesis at the bone-pannus interface in patients with rheumatoid arthritis as well as a receptor activator of NF-kappaB ligand (RANKL). Imatinib mesylate inhibits the phosphorylation of c-fms, a receptor for M-CSF. The present study investigates the effect of imatinib mesylate on joint destruction in rats with collagen-induced arthritis (CIA) and on osteoclastogenesis in vitro. Imatinib mesylate (50 or 150 mg/kg), dexamethasone, or vehicle was administered daily to CIA rats for 4 weeks from the onset of arthritis. Hind-paw swelling and body weight were measured weekly. At weeks 2 and 4, the metatarsophalangeal (MTP) joints and the ankle and subtalar joints were radiographically and histologically assessed. The effect of imatinib mesylate on osteoclast formation from rat bone marrow cells with M-CSF and soluble RANKL (sRANKL) in vitro was also examined. Radiographic assessment showed that 150 mg/kg imatinib mesylate suppressed the destruction of the MTP and the ankle and subtalar joints at week 2, and MTP joint destruction at week 4 in CIA rats, although hind-paw swelling was not suppressed. The number of TRAP-positive cells at the bone-pannus interface was significantly reduced in the group administered with 150 mg/kg imatinib mesylate compared with that given vehicle at week 4. Imatinib mesylate dose-dependently inhibited the proliferation of M-CSF-dependent osteoclast precursor cells in vitro as well as osteoclast formation induced by M-CSF and sRANKL. These findings suggest that imatinib mesylate could prevent joint destruction in patients with rheumatoid arthritis.

Leptin regulates chondrocyte differentiation and matrix maturation during endochondral ossification

Leptin has been suggested to mediate a variety of actions, including bone development, via its ubiquitously expressed receptor (Ob-Rb). In this study, we investigated the role of leptin in endochondral ossification at the growth plate. The growth plates of wild-type and ob/ob mice were analyzed. Effects of leptin on chondrocyte gene expression, cell cycle, apoptosis and matrix mineralization were assessed using primary chondrocyte culture and the ATDC5 cell differentiation culture system. Immunohistochemistry and in situ hybridization showed that leptin was localized in prehypertrophic chondrocytes in normal mice and that Ob-Rb was localized in hypertrophic chondrocytes in normal and ob/ob mice. Growth plates of ob/ob mice were more fragile than those of wild-type mice in a mechanical test and were broken easily at the chondro-osseous junction. The growth plates of ob/ob mice showed disturbed columnar structure, decreased type X collagen expression, less organized collagen fibril arrangement, increased apoptosis and premature mineralization. Leptin administration in ob/ob mice led to an increase in femoral and humeral lengths and decrease in the proportional length of the calcified hypertrophic zone to the whole hypertrophic zone. In primary chondrocyte culture, the matrix mineralization in ob/ob chondrocytes was stronger than that of wild-type mice; this mineralization in both types of mice was abolished by the addition of exogenous leptin (10 ng/ml). During ATDC5 cell differentiation culture, exogenous leptin at a concentration of 1-10 ng/ml (equivalent to the normal serum concentration of leptin) altered type X collagen mRNA expression and suppressed apoptosis, cell growth and matrix calcification. In conclusion, we demonstrated that leptin modulates several events associated with terminal differentiation of chondrocytes. Our finding that the growth plates of ob/ob mice were fragile implies a disturbance in the differentiation/maturation process of growth plates due to depletion of leptin signaling in ob/ob mice. These findings suggest that peripheral leptin signaling plays an essential role in endochondral ossification at the growth plate.

Adiponectin increases bone mass by suppressing osteoclast and activating osteoblast

Adiponectin, an adipose-derived hormone, exhibits various biological functions, such as increasing insulin sensitivity, protecting hypertension, and suppression of atherosclerosis, liver fibrosis, and tumor growth. Here, we report the role of adiponectin on bone metabolism. C57BL/6J mice were treated with adenovirus expressing lacZ or adiponectin, and their bones were analyzed by three-dimensional microcomputed tomography. Adiponectin-adenovirus treatment increased trabecular bone mass, accompanied by decreased number of osteoclasts and levels of plasma NTx, a bone-resorption marker. In vitro studies showed that adiponectin inhibited M-CSF- and RANKL-induced differentiation of mouse bone marrow macrophages and human CD14-positive mononuclear cells into osteoclasts and also suppressed the bone-resorption activity of osteoclasts. Furthermore, adiponectin enhanced mRNA expression of alkaline phosphatase and mineralization activity of MC3T3-E1 osteoblasts. Our results indicate that adiponectin exerts an activity to increase bone mass by suppressing osteoclastogenesis and by activating osteoblastogenesis, suggesting that adiponectin manipulation could be therapeutically beneficial for patients with osteopenia.

Enhanced generation of endothelial cells from CD34+ cells of the bone marrow in rheumatoid arthritis: Possible role in synovial neovascularization

OBJECTIVE

To examine the capacity of bone marrow CD34+ cells to generate endothelial cells, in order to assess the role of bone marrow in neovascularization in the synovium of rheumatoid arthritis (RA).

METHODS

CD34+ cells purified from the bone marrow of 13 patients with active RA and 9 control subjects (7 osteoarthritis [OA] patients and 2 healthy individuals) were cultured in the presence of stem cell factor (10 ng/ml) and granulocyte-macrophage colony-stimulating factor (1 ng/ml). After 18 days of incubation, the generation of endothelial cells was assessed by flow cytometry. The generation of endothelial cells was compared with the degree of vascularization in the synovial tissues and with the microvessel densities in the synovium, as determined by microscopy. The expression of vascular endothelial growth factor receptor 2/kinase insert domain receptor (KDR) messenger RNA (mRNA) in CD34+ cells was examined by quantitative reverse transcription-polymerase chain reaction.

RESULTS

The generation of CD14+ cells from bone marrow-derived CD34+ cells from RA patients was comparable to that from control subjects. However, the generation of von Willebrand factor (vWF)-positive cells and CD31+/vWF+ cells from RA bone marrow-derived CD34+ cells was significantly higher than that from control subjects (P = 0.004 and P = 0.030, respectively). The generation of vWF+ cells from bone marrow CD34+ cells correlated significantly with the microvessel densities in the synovial tissues (r = 0.569, P = 0.021). Finally, RA bone marrow CD34+ cells expressed KDR mRNA at higher levels than OA bone marrow CD34+ cells.

CONCLUSION

These results indicate that RA bone marrow CD34+ cells have enhanced capacities to differentiate into endothelial cells in relation to synovial vascularization. The data therefore suggest that bone marrow CD34+ cells might contribute to synovial neovascularization by supplying endothelial precursor cells and, thus, play an important role in the pathogenesis of RA.

Matrix extracellular phosphoglycoprotein (MEPE) is highly expressed in osteocytes in human bone

The matrix extracellular phosphoglycoprotein (MEPE) gene is highly expressed in tumors that cause oncogenic hypophosphatemic osteomalacia (OHO). MEPE is also known as one of the bone-tooth matrix proteins and is associated with bone mineralization. We developed a rabbit polyclonal antibody directed against recombinant human MEPE (rhMEPE) after cloning its cDNA from the cDNA library of a nasal tumor tissue causing OHO. Using this antibody, we analyzed the distribution of MEPE in human bones by immunohistochemistry. In bone specimens from normal subjects, MEPE was predominantly expressed by osteocytes and not by osteoblasts. In bone specimens from patients with osteomalacia, however, MEPE was focally expressed by deeply located osteocytes. We also compared the MEPE positivity of osteocytes in mineralized bone and non-mineralized osteoid obtained from patients with osteomalacia and osteoporosis. Among osteomalacia patients, MEPE positivity was seen in 87.5 +/- 8.6% of the osteocytes from mineralized bone compared with 7.8 +/- 6.4% of those from osteoid. Among osteoporosis patients, MEPE positivity was found in 95.3 +/- 0.5% of the osteocytes from mineralized bone compared with 4.9 +/- 5.7% of those from osteoid. MEPE was mainly expressed by osteocytes embedded in the matrix of mineralized bone from patients with osteomalacia or osteoporosis. Our data provide the first histological evidence that MEPE is predominantly expressed by osteocytes in human bone, with significant expression by osteocytes within mineralized bone.

Prevention of the onset and progression of collagen-induced arthritis in rats by the potent p38 mitogen-activated protein kinase inhibitor FR167653

OBJECTIVE

FR167653 is a potent inhibitor of p38 mitogen-activated protein kinase (MAPK) and inhibits tumor necrosis factor alpha (TNFalpha) and interleukin-1 beta (IL-1 beta) production in inflammatory cells. In this study we investigated the effect of FR167653 on collagen-induced arthritis (CIA).

METHODS

Rats with CIA were subcutaneously injected with FR167653 (32 mg/kg/day) starting on the day of the booster injection (day 7) in the prophylactic treatment group and after the onset of arthritis (day 21) in the therapeutic treatment group. Hind-paw swelling, body weight, radiographic and histologic scores, and osteoclast number were evaluated. Cytokine levels in the serum and tissue were assessed by enzyme-linked immunosorbent assays. Flow cytometric analysis of T lymphocytes from bone marrow was performed. The effect of FR167653 on in vitro osteoclast formation induced by soluble receptor activator of nuclear factor kappa B ligand (sRANKL) and TNFalpha was examined.

RESULTS

Swelling of hind paws and loss of weight occurred in the CIA rats, but this was not evident in the prophylactic treatment group. Therapeutic treatment also significantly reduced paw swelling. The mean radiographic and histologic scores as well as the osteoclast numbers were significantly lower in the treatment group than in the CIA rats without treatment. FR167653 treatment reduced the serum levels of TNFalpha and IL-1 beta, lowered the IL-1 beta concentration in the ankle joints, and decreased the CD4-,CD8a+ T cell population in bone marrow. Furthermore, FR167653 inhibited the osteoclast-like cell differentiation induced by both sRANKL and TNFalpha in vitro.

CONCLUSION

FR167653 prevents the onset of arthritis in a prophylactic treatment model and suppresses the progression of joint destruction in a therapeutic treatment model, suggesting that p38 MAPK is a potential therapeutic target for rheumatoid arthritis.

Tartrate resistant acid phosphatase (TRAP) positive cells in rheumatoid synovium may induce the destruction of articular cartilage

OBJECTIVE

To examine the role of tartrate resistant acid phosphatase (TRAP) positive mononuclear and multinucleated cells in the destruction of articular cartilage in patients with rheumatoid arthritis (RA).

METHODS

The presence of TRAP positive cells in the synovial tissue of patients with RA was examined by enzyme histochemistry and immunohistochemistry. Expression of mRNAs for matrix metalloproteinases (MMPs) was assessed by the reverse transcriptase-polymerase chain reaction (RT-PCR) and northern blot analysis. Production of MMPs by mononuclear and multinucleated TRAP positive cells was examined by immunocytochemistry, enzyme linked immunosorbent assay (ELISA) of conditioned medium, and immunohistochemistry of human RA synovial tissue. In addition, a cartilage degradation assay was performed by incubation of (35)S prelabelled cartilage discs with TRAP positive cells.

RESULTS

TRAP positive mononuclear cells and multinucleated cells were found in proliferating synovial tissue adjacent to the bone-cartilage interface in patients with RA. Expression of MMP-2 (gelatinase A), MMP-9 (gelatinase B), MMP-12 (macrophage metalloelastase), and MMP-14 (MT1-MMP) mRNA was detected in TRAP positive mononuclear and multinucleated cells by both RT-PCR and northern blot analysis. Immunocytochemistry for these MMPs showed that MMP-2 and MMP-9 were produced by both TRAP positive mononuclear and multinucleated cells, whereas MMP-12 and MMP-14 were produced by TRAP positive multinucleated cells. MMP-2 and MMP-9 were detected in the conditioned medium of TRAP positive mononuclear cells. TRAP positive mononuclear cells also induced the release of (35)S from prelabelled cartilage discs.

CONCLUSION

This study suggests that TRAP positive mononuclear and multinucleated cells located in the synovium at the cartilage-synovial interface produce MMP-2 and MMP-9, and may have an important role in articular cartilage destruction in patients with RA.