Osteoclast formation and activity in the pathogenesis of osteoporosis in rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is often complicated by generalized osteopenia due to increased bone resorption by osteoclasts. We analysed a number of cellular and humoral factors that influence osteoclast formation from circulating precursors in RA patients.

METHODS

Monocytes isolated from RA patients and normal controls were cultured with macrophage colony-stimulating factor (M-CSF) and nuclear factor-kappaB ligand (RANKL), or with RANKL-expressing UMR106 cells and 1,25 dihydroxyvitamin D(3) [1,25(OH)(2)D(3)]. Osteoclast differentiation was assessed by expression of tartrate-resistant acid phosphatase (TRAP) and vitronectin receptors (VNR) and lacunar resorption.

RESULTS

Osteoclasts formed from RA patients exhibited increased resorptive activity but there was no difference in the relative proportion of circulating osteoclast precursors between RA patients and normal controls. Osteoclast precursors in RA patients were not more sensitive to the osteoclastogenic effects of 1,25(OH)(2)D(3), M-CSF or RANKL. Dexamethasone, but not interleukin (IL) 1beta, tumour necrosis factor alpha and IL-6, increased osteoclast formation and lacunar resorption.

CONCLUSION

There is an increase in the extent of lacunar resorption carried out by osteoclasts formed from circulating precursors in RA patients. This is not due to an increase in the number of circulating precursors or increased sensitivity to the osteoclastogenic effects of 1,25(OH)(2)D(3), M-CSF, RANKL or inflammatory cytokines. Our findings suggest that increased osteoclast functional activity rather than osteoclast formation is more likely to play a role in the generalized bone loss that occurs in RA, and that corticosteroids stimulate osteoclast formation and resorption.

Effect of corticosteroids on human osteoclast formation and activity

Chronic corticosteroid treatment is known to induce bone loss and osteoporosis. Osteoclasts are specialised bone-resorbing cells that are formed from mononuclear phagocyte precursors that circulate in the monocyte fraction. In this study we have examined the effect of the synthetic glucocorticoid, dexamethasone, on human osteoclast formation and bone-resorbing activity. Human monocytes were cultured for up to 21 days on glass coverslips and dentine slices, with soluble receptor activator for nuclear factor kappaB ligand (RANKL; 30 ng/ml) and human macrophage-colony stimulating factor (M-CSF; 25 ng/ml) in the presence and absence of dexamethasone (10(-8) M). The addition of dexamethasone over a period of 7 and 14 days of culture of monocytes (during which cell proliferation and differentiation predominantly occurred) resulted in a marked increase in the formation of tartrate-resistant acid phosphatase-positive multinucleated cells and an increase in lacunar resorption. The addition of dexamethasone to monocyte cultures after 14 days (when resorptive activity of osteoclasts had commenced) reduced the extent of lacunar resorption compared with cultures to which no dexamethasone had been added. The addition of dexamethasone to osteoclasts isolated from giant cell tumours of bone significantly inhibited resorption pit formation. Our findings indicate that dexamethasone has a direct effect on osteoclast formation and activity, stimulating the proliferation and differentiation of human osteoclast precursors and inhibiting the bone-resorbing activity of mature osteoclasts.

Establishment of feeder-independent cloned caprine trophoblast cell line which expresses placental lactogen and interferon tau

A feeder-independent cloned trophoblast cell line, HTS-1, was established from a mature placenta of Shiba goat (Capra hircus). During the growth phase, single HTS-1 cells exhibited ruffled membranes or lamellipodia often accompanied by elongated cell shape, indicating highly motile nature of the cells. At or near confluence, HTS-1 cells formed monolayers with few sign of cellular overlapping. Binucleate cells were found at a high frequency especially in the peripheral regions of monolayers. In small colonies and the monolayers, majority of HTS-1 cells assumed polygonally shaped cobble-stone like morphology characteristic to epithelial cells, although considerable variations in cellular morphology were observed despite of repeated cloning. Time-lapse video recordings of HTS-1 cells during culture revealed that not only the small colonies but also the monolayers near or at confluence were remarkably motile, often causing extreme elongation of the cells within them. The extremely plastic nature of HTS-1 cells in vitro is likely to be the reflection of the extraordinary capacity of caprine trophoblast cells to be stretched to extreme thinness in vivo as shown by electron microscopy. HTS-1 cells cultured on matrigel are highly invasive, and express MT1-MMP which, in the mouse, has been known to be expressed at the invasive edge of trophoblast both in vitro and in vivo. HTS-1 cells express placental lactogen (PL) and interferon-tau (IFNtau), as confirmed by immunocytochemistry, Western blotting and RT-PCR analysis. Both PL and IFNtau expression in the cells appeared to be down-regulated by cell-cell contact. In the medium conditioned by HTS-1 cells, the presence of secretory form of PL and IFNtau was confirmed by Western blotting. The HTS-1 cell line will serve as a useful in vitro model for the analysis of the molecular and/or cellular mechanisms underlying synepitheliochorial placentation in bovidae animals.

Gender- and age-related differences in osteoclast formation from circulating precursors

A number of bone diseases characterised by excessive osteolysis (e.g. osteoporosis and Paget's disease) exhibit a marked gender difference in prevalence and are more common in the elderly population. Bone resorption is carried out by osteoclasts, which are formed by fusion of circulating mononuclear precursor cells of haematopoietic origin. In this study, we have determined whether there are gender- and age-related differences in osteoclast formation from circulating precursors. Peripheral blood mononuclear cells (PBMCs) were co-cultured with UMR106 osteoblast-like cells in the presence of macrophage-colony stimulating factor (M-CSF) and 1,25 dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) or cultured alone in the presence of sRANKL (soluble receptor activator of nuclear factor kappa B ligand) and M-CSF. As assessed by the formation of tartrate resistant acid phosphatase (TRAP)-positive (TRAP(+)) and vitronectin receptor-positive (VNR(+)) multinucleated cells (MNCs), there was no difference in the number of circulating osteoclast precursors in males and females. Lacunar resorption carried out by osteoclasts formed from these precursors was generally increased in males compared with females (P=0.03). An increase in the number of TRAP(+) and VNR(+) MNCs formed from male PBMCs was noted in response to 1,25(OH)(2)D(3) (P<0.005). An increase in lacunar resorption in cultures of PBMCs (10(5) per well) from males was also noted in response to 10(-9) M 1,25(OH)(2)D(3) (P<0.05) and sRANKL (P=0.05), but not M-CSF. The addition of dexamethasone resulted in a marked increase in osteoclast formation and lacunar resorption in both males and females. Post-menopausal females and males of comparable age showed similar levels of osteoclastogenesis. Pre-menopausal women showed similar levels of osteoclastogenesis but less resorption (P=0.01) compared with males of comparable age. These results show that there are specific gender/age-related differences in osteoclast formation and bone resorption and have implications for evaluating osteoclastogenesis in skeletal diseases such as primary osteoporosis and Paget's disease.

Cellular and humoral mechanisms of osteoclast formation and bone resorption in Gorham-Stout disease

Gorham-Stout disease (GSD) is a rare, massively osteolytic condition which is associated with increased vascularity and an increase in osteoclast numbers. To determine the cellular and humoral mechanisms underlying the increase in osteoclast numbers and osteolysis in GSD, this study analysed circulating osteoclast precursor numbers and sensitivity to osteoclastogenic factors in a GSD patient and age/sex-matched controls. Monocytes were cultured with M-CSF (25 ng/ml) and RANKL (30 ng/ml) and osteoclast formation was assessed in terms of the formation of TRAP(+) and VNR(+) multinucleated cells and the extent of lacunar resorption. There was no increase in the proportion of circulating osteoclast precursors in GSD relative to controls, but lacunar resorption was consistently greater in GSD monocyte cultures. Increased osteoclast formation in GSD was noted when monocytes were incubated with IL-1beta (1 ng/ml), IL-6/sIL-6R (100 ng/ml), and TNFalpha (10 ng/ml). An increase in osteoclast differentiation and bone resorption was also noted in control monocyte cultures in the presence of GSD serum. These results indicate that the increase in osteoclast formation in GSD is due not to an increase in the number of circulating osteoclast precursors, but rather to an increase in the sensitivity of these precursors to humoral factors which promote osteoclast formation and bone resorption.

Estimation of vacuolating cytotoxin secreted by different strains of Helicobacter pylori using bead enzyme-linked immunosorbent assay & its correlation with bacterial genotype

BACKGROUND & OBJECTIVES

A highly sensitive bead enzyme-linked immunosorbent assay was applied for the quantitative determination of vacuolating cytotoxin (VacA) released in the culture supernatant of 40 well characterized Helicobacter pylori strains in order to clarify the significance of allelic combination of the vacA gene as the predictor of the level of toxin secretion and also to determine the most appropriate genotype of H. pylori associated with high VacA release. Attempts were also made for the detection of VacA in the gastric juice of patients for the rapid diagnosis of H. pylori infection.

METHODS

The genotypes of 40 H. pylori strains cultured from the gastric biopsy samples were determined by specific PCRs. The cell-free culture supernatant of the strains as well as the gastric juice of the patients were used for bead-ELISA and the purified VacA from the H. pylori strain ATCC49503 was used as positive control.

RESULTS

Ninety per cent of the strains with vacAs1m1 allele combination secrete on an average 146.4 ng/ml of VacA while the corresponding value was 19.1 ng/ml for s1m2 strains. None of the s2m2 as well as the ice negative H. pylori strains produced detectable VacA in the medium while strains expressed the toxin irrespective of the presence or absence of cagA gene. Fifteen of 22 gastric juice samples yielded positive bead-ELISA results.

INTERPRETATION & CONCLUSION

vacAs1, vacAm1 and iceA1 could be considered as the determinants of high VacA secretion. Also, the detection of VacA by bead-ELISA in the gastric juice could be considered as an alternative approach in the diagnosis of H. pylori infection.

Production of beta-defensin-2 by human colonic epithelial cells induced by Salmonella enteritidis flagella filament structural protein

We recently showed that FliC of Salmonella enteritidis increased human beta-defensin-2 (hBD-2) expression, and now describe the signaling responsible pathway. FliC increased the intracellular Ca(2+) concentration ([Ca(2+)](in)) in Caco-2 cells. The [Ca(2+)](in) increase induced by FliC was prevented by U73122 and heparin, but not by chelating extracellular Ca(2+) or pertussis toxin. The FliC-induced increase in hBD-2 promoter activity via nuclear factor kappaB (NF-kappaB) was also inhibited by chelation of intracellular Ca(2+) or by U73122. We conclude that FliC increased [Ca(2+)](in) via inositol 1,4,5-trisphosphate, which was followed by up-regulating hBD-2 mRNA expression via an NF-kappaB-dependent pathway.

Synthesis of 2-phenylbenzotriazole-type mutagens, PBTA-5 and PBTA-6, and their detection in river water from Japan

We previously determined the chemical structures of four 2-phenylbenzotriazole mutagens (PBTA-1, -2, -3 and -4) in blue rayon-adsorbed material from the Nishitakase River in Kyoto prefecture and the Nikko River in Aichi prefecture in Japan. On the basis of a synthesis study, these four PBTA derivatives were deduced to have originated from corresponding dinitrophenylazo dyes by reduction and chlorination. 2-[(2-Bromo-4,6-dinitrophenyl)azo]-5-[bis(2-acetoxyethyl) amino]-4-methoxyacetanilide (Color Index Name, Disperse Blue 79:1; CAS Registry Number, 75497-74-4) is a very common dinitrophenylazo dye used in textile dyeing factories. In the present study, we synthesized 2-[4-[bis(2-acetoxyethyl)amino]-2-(acetylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-5) from Disperse Blue 79:1 by reduction with sodium hydrosulfite and subsequent chlorination with sodium hypochlorite. On hydrolysis of PBTA-5 with alkali, 2-[2-(acetylamino)-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6) was obtained. Both PBTA-5 and -6 were potent mutagens, inducing 723,000 revertants and 485,000 revertants per microgram of Salmonella typhimurium YG1024, respectively, in the presence of S9 mix. To clarify whether PBTA-5 and -6 exist in the environment, water samples were collected from five rivers flowing through regions where textile dyeing industries are developed. PBTA-6 was detected at levels of 3-134 ng/g blue rayon in all water samples that were examined. On the other hand, the amount of PBTA-5 in the samples was less than the detection limit.

Fatal acute hepatic failure induced by danazol in a patient with endometriosis and aplastic anemia

We describe a 47-year-old woman with severe aplastic anemia with genital bleeding who developed acute severe hepatitis after the administration of danazol while she was receiving cyclosporin. She had been diagnosed with severe aplastic anemia 1 year previously and, while hospitalized, had received methyl prednisolone pulse therapy, which was not successful. She was then referred to our hospital. She was treated with antithymocyte globulin, cyclosporin, granulocyte colony-stimulating factor, and methyl prednisolone; a good response was achieved after 3 months of this therapy. Subsequently, oral administration of cyclosporin was continued, but she was readmitted to our hospital when pancytopenia gradually developed and the genital bleeding recurred. Danazol was administered for pancytopenia and endometriosis. Four days after the first administration of danazol, epigastric pain occurred, and the danazol was stopped. Eighteen days after the first danazol administration, very severe hepatic injury occurred abruptly. The patient died of hepatic failure. Postmortem examination revealed centrilobular massive necrosis of the liver. Danazol was implicated as the agent responsible for causing the hepatic failure. Drug interactions between danazol and cyclosporin may cause adverse effects.

Expression of human beta-defensin 2 (hBD-2) in Helicobacter pylori induced gastritis: antibacterial effect of hBD-2 against Helicobacter pylori

BACKGROUND

Human beta-defensin 2 (hBD-2) plays a role in the innate defence system at mucosal surfaces. Colonisation of Helicobacter pylori in the stomach is an important pathological factor in gastrointestinal illnesses, including gastritis, peptic ulcer, and gastric adenocarcinoma.

AIMS

To evaluate the antibacterial role of hBD-2 against H pylori infection in the gastric mucosa.

SUBJECTS

Biopsied gastric mucosa specimens from H pylori positive (n=6) and H pylori negative (n=6) individuals were used. H pylori was determined by the presence of urease activity and microscopic examination.

METHODS

The specimens were examined for hBD-2 expression by reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, and in situ hybridisation. The antibacterial effect of hBD-2 against H pylori was evaluated by the number of colony forming units of H pylori after incubation with 0, 10(-9), 10(-8), 10(-7), 10(-6), or 10(-5) M of hBD-2 peptide.

RESULTS

All six H pylori positive specimens expressed a high level of hBD-2 mRNA while hBD-2 mRNA was not detected in the H pylori negative specimens by RT-PCR. Immunohistochemistry using anti-hBD-2 antiserum revealed that hBD-2 was expressed in the surface epithelium of H pylori infected specimens. In gastric specimens obtained after H pylori eradication, hBD-2 immunoreactivity had dramatically decreased. In situ hybridisation confirmed that hBD-2 transcripts were localised in the epithelium of H pylori infected gastric specimens. Incubation with hBD-2 reduced the growth rate of cultured H pylori in a dose dependent manner, and incubation with 10(-5) M hBD-2 completely inhibited the proliferation of H pylori.

CONCLUSIONS

H pylori infection induces hBD-2 expression in the human gastric epithelium. hBD-2 inhibited the growth of H pylori in vitro, suggesting that hBD-2 plays an antibacterial role in H pylori induced gastritis.

[Surgical management of non-tuberculous mycobacteriosis and tuberculosis of the lung]

From 1990 to 1999, three patients with non-tuberculous mycobacteriosis and 14 patients of tuberculosis underwent pulmonary resection in the National Sanatorium Ehime Hospital. Of the patients with tuberculosis, two were multiple drug-resistant cases and twelve cases were suspected of lung cancer before diagnostic resection. All three patients with non-tuberculous mycobacteriosis were symptomatic, had chest cavities in the lung, and were sputum-culture positive. There were no operative death in all patients, and one case of post-operative complication. Two patients, one with non-tuberculous mycobacteriosis and another with tuberculosis, failed in sputum negative conversion. The former had been treated for a long time preoperatively. Early resection in patients of pulmonary non-tuberculous mycobacteriosis and of pulmonary multiple drug-resistant tuberculosis is recommended to prevent further progression of pulmonary lesions.

Effect of chronic treatment with haloperidol on vasopressin release and behavioral changes by osmotic stimulation of the supraoptic nucleus

Chronic treatment with dopamine D2 blockers in schizophrenic patients has been proposed as one of the causes of polydipsia and water intoxication, but this conclusion is still controversial. To investigate the relationship between dopamine D2 blockers and these syndromes, we designed a behavioral and neurochemical study using hyperosmotic stimulation in the supraoptic nucleus (SON) by microdialysis after chronic treatment with haloperidol in rats. Animals were injected with haloperidol decanoate (20 mg/kg, i.m.) or sesame oil at 2-week intervals for 8 successive weeks. During the 7th week, water-intake was increased 30-60 min after the hyperosmotic stimulation in both groups, but more so in haloperidol-treated animals compared to that in the control group. Moreover, arginine vasopressin (AVP) was released by the hyperosmotic stimulation in SON, but was not significantly different between groups. In addition, striatal dopamine levels 3-4 days after the microdialysis study showed a significant decrease in the haloperidol-treated animals. These results suggest that chronic treatment with haloperidol enhances water-intake produced by hyperosmotic stimulation in the SON but does not increase AVP levels in dialysates following hyperosmotic stimulation. Thus, these symptoms may be mediated by dopaminergic systems in brain.

Salmonella enteritidis FliC (flagella filament protein) induces human beta-defensin-2 mRNA production by Caco-2 cells

Antimicrobial peptides are crucial for host defense at mucosal surfaces. Bacterial factors responsible for induction of human beta-defensin-2 (hBD-2) mRNA expression in Caco-2 human carcinoma cells were determined. Salmonella enteritidis, Salmonella typhimurium, Salmonella typhi, Salmonella dublin, and culture supernatants of these strains induced hBD-2 mRNA expression in Caco-2 human carcinoma cells. Using luciferase as a reporter gene for a approximately 2.1-kilobase pair hBD-2 promoter, the hBD-2-inducing factor in culture supernatant of S. enteritidis was isolated. The supernatant factor was heat-stable and proteinase-sensitive. After purification by anion exchange and gel filtration chromatography, the hBD-2-inducing factor was identified as a 53-kDa monomeric protein with the amino-terminal sequence AQVINTNSLSLLTQNNLNK, which is identical to that of the flagella filament structural protein (FliC) of S. enteritidis. Consistent with this finding, the 53-kDa protein reacted with anti-FliC antibody, which prevented its induction of hBD-2 mRNA in Caco-2 cells. In agreement, the hBD-2-inducing activity in culture supernatant was completely neutralized by anti-FliC antibody. In gel retardation analyses, FliC increased binding of NF-kappaB (p65 homodimer) to hBD-2 gene promoter sequences. We conclude that S. enteritidis FliC induces hBD-2 expression in Caco-2 cells via NF-kappaB activation and thus plays an important role in up-regulation of the innate immune response.

[Survival after oozing type cardiac rupture associated with subepicardial aneurysm evaluated by echocardiography: a case report]

A 64-year-old woman was admitted to our hospital with acute myocardial infarction. She underwent emergent percutaneous transluminal coronary angioplasty. Transthoracic echocardiography revealed mild pericardial effusion on the third day. Pericarditis or cardiac rupture were suspected, so transthoracic echocardiography was repeated serially. On the sixth day, transthoracic echocardiography showed increasing pericardial effusion and abrupt interruption of the apical myocardium of the left ventricle and intact epicardial imaging with systolic expansion. The diagnosis was oozing type cardiac rupture of a subepicardial aneurysm. Surgical treatment was successful and the accuracy of the echocardiographic diagnosis was established.

Effect of particle size on macrophage-osteoclast differentiation in vitro

To determine whether particle size affects macrophage-osteoclast differentiation in vitro, latex beads of 0.1, 1, and 10 microm in diameter were added to a murine macrophage-UMR106 osteoblast-like cell coculture system. The extent of osteoclast differentiation was determined by assessing the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells on glass coverslips and the extent of lacunar resorption on dentine slices. The addition of particles, 1 and 10microm in size, to the cocultures resulted in a significant increase in the number of TRAP-positive osteoclast-like cells and in the resorption pit surface area compared with findings in control cultures to which no particles had been added. Particles 0.1 microm in size also stimulated osteoclast formation relative to the control; however, the difference was not significant. These results indicate that particles, particularly these 1 and 10microm in size, sizes which were phagocytosable, significantly enhanced the process of macrophage-osteoclast differentiation and suggest that particle size plays an important role in periprosthetic osteolysis.

Impairment of glutathione metabolism in human gastric epithelial cells treated with vacuolating cytotoxin from Helicobacter pylori

Helicobacter pylori vacuolating cytotoxin (VacA) is believed to be one of the factors that induces gastric disease. Our previous study indicated that VacA causes a decrease in the intracellular ATP level in human gastric epithelial cells, suggesting to impair mitochondrial membrane potential followed by a decrease in energy metabolism (Kimura et al., Microb. Pathog., 1999, 26: 45--52). In the present study, we investigated whether the decrease in ATP level affects glutathione metabolism, in which its synthesis and efflux are ATP-dependent. Treatment of AZ-521 human gastric epithelial cells with 120 nM VacA for 6 h suppressed the efflux of oxidized glutathione (GSSG) in a dose- and time-dependent manner. The efflux of GSSG from the cells and glutathione (GSH) synthesis of cells treated with VacA were approximately 50 and 70% of those of the control, respectively. The turnover rate of intracellular GSH was also suppressed by VacA. Viability of the cells pretreated with VacA, then further incubated with H(2)O(2), was decreased by 50% at 6 h and 70% at 12 h. These results suggested that VacA impairs GSH metabolism in the gastric epithelial cells, which weakens the resistance of the cells against oxidative stress or cellular redox regulation by GSH.

[Postoperative right ventricular function after repair of tetralogy of Fallot with respect to the method of right ventricular outflow tract reconstruction]

We evaluated postoperative right ventricular function in the sixty-four consecutive patients with tetralogy of Fallot underwent total correction. The patients were divided to three groups according to the method of right ventricular outflow tract reconstruction: transannular patching (TA group; n = 31); right ventricular outflow patching with preservation of pulmonary valve ring (RV group; n = 12) and transatrial-transpulmonary approach without right ventriculotomy (no-RV group; n = 21). The early results of postoperative cardiac catheterization and echocardiography were compared among the three groups. Degree of pulmonary regurgitation was significantly low in the RV group and no-RV group compared with TA group (p < 0.005). Right ventricular ejection fraction was the highest in the no-RV group (p < 0.002). The repair without right ventriculotomy for tetralogy of Fallot can provide the best results with respect to postoperative right ventricular function.

[Clinical investigation of cefpirome for perinatal infection and infection prevention]

Effectiveness and safety of cefpirome (CPR) were studied in perinatal infection and prevention of postoperative infections. 1. Enrolled in the study of perinatal infections were the total 62 cases comprising 47 of chorioamnionitis, 10 of puerperal intrauterine infections, 1 of infectious abortion and 4 of others. The effective rate of CPR 2 g/day given in drip infusion was 61/62 (98.4%). In bacteriological studies, the bacterial elimination rate was 57/61 (93.4%). Unchanged and remained were 3 strains of Gram-positive bacteria and 1 strain of Bacteroides spp. 2. Enrolled in the study of prevention of postoperative infections during perinatal period were the total 88 cases comprising 74 who underwent cesarean section and 14 others. The effective rate of CPR 2 g/day given in drip infusion was 87/88 (98.9%). 3. With respect to subjective and objective adverse affects due to the agent, drug eruption was observed in 1/150 (0.7%). No abnormal result of clinical laboratory tests was found. The above results suggested the usefulness of CPR for treatment of perinatal infections and prevention of postoperative infections.