Impact of Renal Transplantation and Nephrectomy on Urinary Soluble Klotho Protein.

BACKGROUND: Klotho is a single-pass transmembrane protein predominantly expressed in the kidneys. The soluble form of klotho has been shown to participate in various pathophysiological activities. However, information regarding the kinetics of soluble klotho remains limited. We herein assessed serial changes in the amounts of 24-hour urinary excreted soluble klotho among renal transplant recipients and concomitant living donors before and after transplantation. METHODS: A total of 15 recipients and donors were included in the current study, and the amounts of urinary soluble klotho were quantified using a sandwich enzyme-linked immunosorbent assay. RESULTS: Urine samples were available in 6 of the 15 recipients prior to the procedure. The amounts of urinary klotho in these 6 recipients and overall living donors at the baseline were 58.6 ng/day (IR: 29.3-142) and 698.8 ng/day (IR: 62.3-1619.5), respectively. Those in the recipients on postoperative day 2 (median 522.3 ng/day; IR 337.1-1168.5, P < .05) and day 5 (median 723.2 ng/day; IR 254.7-1238.6, P < .05) were significantly higher than the baseline values. Among the living donors, only a transient increase was observed in the amounts of urinary klotho on postoperative day 2. CONCLUSION: The current data regarding the urinary soluble klotho in recipients support the hypothesis that the kidney is a major source of urinary soluble klotho among the numerous components of the urinary tract. In living donors, the complex nature of events associated with acute reductions in the renal mass may modulate the release of soluble klotho from the kidneys into the urine.

TGF-ß1-siRNA delivery with nanoparticles inhibits peritoneal fibrosis.

Gene therapies may be promising for the treatment of peritoneal fibrosis (PF) in subjects undergoing peritoneal dialysis (PD). However, a method of delivery of treatment genes to the peritoneum is lacking. We attempted to develop an in vivo small interfering RNA (siRNA) delivery system with liposome-based nanoparticles (NPs) to the peritoneum to inhibit PF. Transforming growth factor (TGF)-ß1-siRNAs encapsulated in NPs (TGF-ß1-siRNAs-NPs) dissolved in PD fluid were injected into the peritoneum of mice with PF three times a week for 2 weeks. TGF-ß1-siRNAs-NPs knocked down TGF-ß1 expression significantly in the peritoneum and inhibited peritoneal thickening with fibrous changes. TGF-ß1-siRNAs-NPs also inhibited the increase of expression of α-smooth muscle actin-positive myofibroblasts. These results suggest that the TGF-ß1-siRNA delivery system with NPs described here could be an effective therapeutic option for PF in subjects undergoing PD.

Unusual association of NDM-1 with KPC-2 and armA among Brazilian Enterobacteriaceae isolates.

We report the microbiological characterization of four New Delhi metallo-ß-lactamase-1 (blaNDM-1)-producing Enterobacteriaceae isolated in Rio de Janeiro, Brazil. blaNDM-1 was located on a conjugative plasmid and was associated with Klebsiella pneumoniae carbapenemase-2 (blaKPC-2) or aminoglycoside-resistance methylase (armA), a 16S rRNA methylase not previously reported in Brazil, in two distinct strains of Enterobacter cloacae. Our results suggested that the introduction of blaNDM-1 in Brazil has been accompanied by rapid spread, since our isolates showed no genetic relationship.

The impact of nephrectomy and renal transplantation on serum levels of soluble Klotho protein.

BACKGROUND: Klotho, a single-pass transmembrane protein primarily expressed in the kidneys, parathyroid glands, and choroid plexus of the brain, has a short cytoplasmic tail and a long extracellular domain, which can be cleaved and released as a soluble form. However, information regarding the origins and kinetics of soluble serum Klotho remains poorly understood. We evaluated serial changes in serum Klotho levels among living donors before and after retroperitoneoscopic nephrectomy as well as in their renal transplant recipients. METHODS: The levels of soluble Klotho in serum obtained from 10 living donors and their renal transplant recipients were determined using a sandwich enzyme-linked immunosorbent assay system. RESULTS: Serum soluble Klotho was detectable in all subjects. The baseline serum Klotho concentrations in the living donors ranged from 726.4 to 1417.1 pg/mL (median, 909.8 pg/mL; interquartile ranges [IR], 754.8-1132.4), whereas that in the concomitant renal transplant recipients ranged from 397.5 to 1047.2 pg/mL (median, 613.0 pg/mL; IR, 445.9-750.8; P = .003). The levels of soluble serum Klotho measured 5 days after retroperitoneoscopic nephrectomy (median, 619.0 pg/mL; IR, 544.6-688.5; P = .001) were significantly lower than the baseline values. Among the renal transplant recipients, no significant changes in serum Klotho levels were observed during the observation period. CONCLUSION: Our data regarding soluble serum Klotho levels obtained from living donors support the idea that the kidneys are a major source of soluble serum Klotho in human subjects without a deterioration of renal function. In recipients, concomitant acute kidney injuries and immunosuppressive protocols might modulate the release of soluble Klotho from the grafts into the circulation.

Interleukin-10 expression induced by adeno-associated virus vector suppresses proteinuria in Zucker obese rats.

Varying degrees of metabolic abnormalities mediated by chronic inflammation are implicated in the chronic glomerular injuries associated with obesity. Interleukin (IL)-10, a pleiotropic cytokine, exerts anti-inflammatory effects in numerous biological settings. In the present study, we explored the biological benefits of adeno-associated virus (AAV) vector-mediated sustained IL-10 expression against the pathological renal characteristics observed in Zucker fatty rats (ZFRs). We injected an AAV vector, encoding rat IL-10 or enhanced green fluorescent protein (GFP) into male ZFRs at 5 weeks of age. Subsequently, the renal pathophysiological changes were analyzed. Persistent IL-10 expression significantly reduced the urinary protein excretion of ZFRs compared with GFP expression (47.1±11.6 mg per mg·creatinine versus 88.8±30.0 mg per mg·creatinine, P<0.01). The serum levels of IL-10 negatively correlated with the urinary protein in AAV-treated rats (r=-0.78, P<0.01). Renal hypertrophy, increased widths in the glomerular basement membrane, and the lack of uniformity and regularity of the foot process of the visceral glomerular epithelial cells of ZFRs were significantly blunted by IL-10 expression. IL-10 also abrogated the downregulation of glomerular nephrin observed in ZFRs treated with the GFP vector. Our findings provide insights into the potential benefit of the anti-inflammatory effects of IL-10 on the overall management of glomerulopathy induced by the metabolic disorders associated with obesity.

Two cases of renal hypouricemia in which dopamine infusion produced a good recovery from exercise-induced acute kidney injury.

We report 2 cases with a good recovery from acute kidney injury (AKI) due to exercise-induced AKI associated with renal hypouricemia. Case 1 involves a 20-yearold man who had a similar episode 1 year earlier. He complained of nausea, vomiting and loin pain after playing football. On admission, his serum creatinine was 3.27 mg/dl and he was treated with intravenous fluid infusion (2 l/d). His renal function deteriorated and creatinine rose to 9.82 mg/dl. A renal hemodynamic evaluation using duplex Doppler ultrasound showed a high arterial resistance index (RI). After we changed his treatment to intravenous continuous infusion of 2 µg/kg/min dopamine, RI decreased sequentially and creatinine decreased without hemodialysis. A renal biopsy performed 7 days after dopamine infusion showed no changes in glomeruli and tubules, suggesting the absence of acute tubular necrosis, and no uric acid crystals or myoglobin casts in tubules. Case 2 involves a 42-year-old man who complained of loin pain after riding a motorcycle. On admission, his creatinine and creatine phosphokinase (CPK) were 3.93 mg/dl and 59 mU/ml, respectively. His RI was also high and he was treated immediately with an intravenous continuous infusion of 2 µg/kg/min dopamine. RI and creatinine decreased sequentially. Both cases suggest the effectiveness of dopamine infusion for AKI due to renal hypouricemia in which the RI of the renal arteries is high.

Pseudoaldosteronism with increased serum cortisol associated with pneumonia, hypouricemia, hypocalcemia, and hypophosphatemia.

We describe here the interesting case of a 73-year-old hypertensive man with pseudoaldosteronism. He had been taking glycyrrhizin at a dose of 75 mg/day for 12 years because of mild liver damage, but had never experienced any previous symptoms associated with hypokalemia. He was referred to our hospital because of hypokalemic tetraparesis and rhabdomyolysis. At that time, we noted mineralocorticoid excess characterized by hypokalemia due to urinary K loss, exacerbation of hypertension due to increased tubular Na reabsorption, metabolic alkalosis, and suppression of both plasma renin activity and plasma aldosterone concentration. His urinary free cortisol excretion rate and the urinary ratio of free cortisol to free cortisone were markedly elevated. Thus we diagnosed pseudoaldosteronism that was related to the long-term use of glycyrrhizin. When he developed pseudoaldosteronism, he also contracted pneumonia, and exhibited elevated levels of serum cortisol and creatinine clearance (CCr) as well as hypouricemia, hypocalcemia, and hypophosphatemia. All normalized after the recovery from pneumonia and the administration of spironolactone. The extracellular volume expansion associated with increased tubular Na reabsorption by the aldosterone-sensitive distal nephron and the resulting increase in CCr caused an inhibition of proximal tubular reabsorption of uric acid, Ca, and inorganic phosphate, leading to their renal loss and therefore hypouricemia, hypocalcemia, and hypophosphatemia, respectively. In this patient, the increased circulating cortisol associated with the stress of inflammation caused by pneumonia triggered the development of pseudoaldosteronism.

Hypertension induced by erythropoietin has a correlation with truncated erythropoietin receptor mRNA in endothelial progenitor cells of hemodialysis patients.

Endothelial nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) contribute to erythropoietin (EPO)-induced hypertension, a major adverse reaction associated with EPO therapy. To investigate the mechanism of EPO-induced hypertension, we examined circulating endothelial progenitor cells (EPCs) taken from 56 hemodialysis (HD) patients. Among these EPCs (which reflect the condition of the endothelium), we looked for EPO receptor (EPOR) mRNAs. A truncated form of EPOR acts as a dominant negative regulator of EPO signaling, leading to hypertension. We found that the ratio of truncated EPOR mRNA in EPCs has a correlation with EPO-induced increase in blood pressure (r = 0.36, P = 0.02). The ratio of truncated to total EPOR mRNA in EPCs had an inverse correlation with EPO-induced cGMP production in vitro (r = -0.31, P = 0.02). A similar correlation was observed in cultured human endothelial cells after transfection of the full-length or truncated forms of EPOR (r = -0.92, P < 0.001). It follows, therefore, that evaluation of EPOR isoform mRNA in EPCs can predict EPO-induced hypertension. The termination of the EPO signal by truncated EPORs may decrease NO/cGMP production after EPO exposure, thereby raising blood pressure.

A case of minimal change nephrotic syndrome with acute renal failure complicating Hashimotoâs disease.

A 63-year-old man was admitted to our hospital for evaluation of generalized edema. Coexistence of severe hypothyroidism and nephrotic syndrome was detected by laboratory examination. High titer of both antimicrosomal antibody and antithyroid peroxidase antibody indicated Hashimotoâs disease. Renal biopsy showed minimal change glomerular abnormality, but no findings of membranous nephropathy. A series of medical treatments, including steroid therapy, thyroid hormone and human albumin replacement therapy, were administered. However, acute renal failure accompanied by hypotension, was not sufficiently prevented. After 9 sessions of plasmapheresis therapy, the severe proteinuria and low serum albumin levels were improved. Even after resting hypotension was normalized, neither renal function nor thyroid function were fully recovered. After discharge, renal function gradually returned to normal, and the blood pressure developed into a hypertensive state concomitant with the normalization of thyroid function. This report is a rare case of autoimmune thyroid disease complicated with minimal change nephrotic syndrome. In most cases of nephritic syndrome, acute renal failure (ARF) has been reported to coexist with hypertension. Although pseudohypothyroidism is well-known in nephrotic pathophysiology, complications of actual hypothyroidism are uncommon. It is suggested that the development of hypotension and ARF could be enhanced not only by hypoproteinemia, but also by severe hypothyroidism.

Complete remission of minimal-change nephrotic syndrome induced by apheresis monotherapy.

We report a case of a 17-year-old male with relapse of minimal-change nephrotic syndrome (MCNS), in whom apheresis monotherapy without steroids or immunosuppressants resulted in complete remission. The patient initially developed nephrotic syndrome in February 1998. The first renal biopsy confirmed the diagnosis of MCNS. The patient was also found to be a carrier of hepatitis B virus. Steroid therapy was started with oral prednisolone 60 mg/day. Complete remission was achieved in 3 months, and the steroid treatment was tapered off in May 2001. During the steroid tapering, temporal exacerbation of liver function was noted. In July 2002, the patient was admitted to our hospital again due to relapse of nephrotic syndrome. Second biopsy reconfirmed the diagnosis of MCNS. Since the serum titer of HBV was elevated, apheresis monotherapy was selected to avoid the risk of steroid-induced fulminant hepatitis. Four sessions of low-density lipoprotein apheresis (LDL-A) and 5 sessions of double-filtration plasmapheresis (DFPP) reduced the proteinuria from 9.2 g/day to 0.2 g/day over 38 days without any additional medication. Proteinuria remained suppressed below 0.2 g/day for more than 12 months and no exacerbation of liver function was observed up to the final follow-up in September 2003. The present case suggested the potential of apheresis monotherapy to induce and maintain complete remission of MCNS and an important role of circulating factors in the pathogenesis of MCNS.

Fanconi's syndrome and distal (type 1) renal tubular acidosis in a patient with primary Sjögren's syndrome with monoclonal gammopathy of undetermined significance.

Tubulointerstitial nephritis is a well-recognized complication in primary Sjögrens syndrome. Fanconi's syndrome is a far less frequent complication compared with distal tubular dysfunction. We here describe a 49-year-old woman with primary Sjögren's syndrome. In 1997, she was diagnosed with primary Sjögren's syndrome with tubulointerstitial nephritis, and was then treated with oral prednisolone for the tubulointerstitial nephritis. In 2002, she was referred to our hospital because of progressive fatigue. At that time, biclonal spike on serum protein (IgG-kappa and IgA-kappa) and Bence-Jones protein in urine were found. Bone marrow aspiration showed 1.0% plasma cell infiltration. Thus, a diagnosis of monoclonal gammopathy of undetermined significance (MGUS) was made. In 2004, she was again admitted to our hospital because of mild renal dysfunction and hypokalemia. Laboratory evaluation showed inappropriate, alkaline urine in hyperchloremic metabolic acidosis and a positive urine anion gap, indicating the presence of distal (Type 1) renal tubular acidosis (RTA). The urine concentration defect was also found. Further studies revealed proximal tubular dysfunction, including renal glycosuria, generalized aminoaciduria, phosphaturia, uricosuria and proximal RTA. The kidney biopsy represented diffuse and severe tubulointerstitial nephritis with dense infiltrates of lymphocytes and IgA and K light chain-positive plasma cells. No findings of multiple myeloma or malignant lymphoma were observed. In conclusion, our patient had Sjögren's syndrome with MGUS and exhibited dysfunction of both proximal tubule (Fanconi's syndrome) and distal tubule, which may be attributed to diffuse tubulointerstitial nephritis.

Indoxyl sulfate stimulates proliferation of rat vascular smooth muscle cells.

Vascular smooth muscle cell (VSMC) proliferation is a key event in the progression of arteriosclerosis. Clinical studies show that uremic toxins deteriorate the arteriosclerosis in renal failure patients. Indoxyl sulfate (IS) is a strong protein-bound uremic toxin, but the effect of IS on VSMC proliferation has not been studied. We examined the effect of IS on rat VSMC proliferation, assessed by a cell counting kit (4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] assay) and by [(3)H]thymidine incorporation in vitro. We further evaluated a contribution of mitogen-activated protein kinase (MAPK; p44/42 MAPK) to VSMC proliferation by IS. Immunohistochemical staining was performed for VSMCs using antirat organic anion transporter (OAT)3 antibody. The mRNA expressions of platelet-derived growth factor (PDGF)-A and -C chains, and PDGF-beta receptor were evaluated by real-time PCR. IS stimulated the proliferation of VSMCs in a concentration-dependent manner and activated p44/42 MAPK. Concentration of IS needed to stimulate the proliferation of rat VSMC was about 250 microM, which is compatible with that in the serum of end-stage renal failure patients. PD98059 (10 microM), a selective inhibitor of MAPK/extracellular signal-regulated kinase, inhibited the IS-induced (250 microM) VSMC proliferation and phosphorylation of MAPK. Probenecid (0.5 mM), an inhibitor and substrate of OAT, inhibited the IS-induced (250 microM) VSMC proliferation. Rat OAT3 was detected in VSMCs. The mRNA expressions of PDGF-C chain and PDGF-beta receptor were significantly increased by IS. We conclude that IS directly stimulates rat VSMC proliferation and activates MAPK in vitro. This might be one of the mechanisms underlying the progression of atherosclerotic lesions in end-stage renal disease patients.

Reversible hypocalcemic heart failure with T wave alternans and increased QTc dispersion in a patient with chronic renal failure after parathyroidectomy.

Despite the crucial role of calcium in myocardial contractility, hypocalcemia has very rarely been reported as a reversible cause of heart failure. In this article, we describe a case of a 51-year-old woman with advanced stages of chronic renal failure after parathyroidectomy who exhibited congestive heart failure, severe hypocalcemia, hypomagnesemia and hypokalemia. Severe hypocalcemia resulted from discontinuation of taking calcium supplements after parathyroidectomy and from reduced 1.25(OH)2D3 synthesis by damaged kidneys. The patient presented with reduced left ventricular ejection fraction (EF) and ECG abnormalities (T wave alternans and increased QTc dispersion), both of which improved after correction of serum calcium levels. Her serum levels of total calcium corrected for serum albumin, but not serum levels of magnesium or potassium, positively and negatively correlated with EF and QTc dispersion, respectively. In the present case, both heart failure and the ECG abnormalities are directly associated with hypocalcemia.

Histone deacetylase inhibitor FK228 suppresses the Ras-MAP kinase signaling pathway by upregulating Rap1 and induces apoptosis in malignant melanoma.

Histone deacetylase (HDAC) inhibitors are expected to be effective for refractory cancer because their mechanism of action differs from that of conventional antineoplastic agents. In this study, we examined the effect of the HDAC inhibitor FK228 on malignant melanoma, as well as its molecular mechanisms. FK228 was highly effective against melanoma compared with other commonly used drugs. By comparing the gene expression profiles of melanoma cells and normal melanocytes, we defined a subset of genes specifically upregulated in melanoma cells by FK228, which included Rap1, a small GTP-binding protein of the Ras family. The expression of Rap1 mRNA and protein increased in FK228-treated melanoma cells in both a dose- and a time-dependent manner. A decrease in the phosphorylation of c-Raf, MEK1/2, and ERK1/2 was accompanied by an increase in Rap1 expression in both FK228-treated and Rap1-overexpressing cells. Inhibition of Rap1 upregulation by small interfering RNA (siRNA) abrogated the induction of apoptosis and suppression of ERK1/2 phosphorylation in FK228-treated melanoma cells. These results indicate that the cytotoxic effects of FK228 are mediated via the upregulation of Rap1. Furthermore, we found that Rap1 was overexpressed and formed a complex with B-Raf in melanoma cell lines with a V599E mutation of B-Raf. The siRNA-mediated abrogation of Rap1 overexpression increased the viability of these cells, suggesting that Rap1 is also an endogenous regulator of Ras-MAP kinase signaling in melanomas.

Combined treatment with nafamostat mesilate and aspirin prevents heparin-induced thrombocytopenia in a hemodialysis patient.

We report on the management of a 36-year-old hemodialysis patient with heparin-induced thrombocytopenia (HIT, type II) and clot formation in extracorporeal circulation. Platelet aggregation test and measurement of anti-platelet factor 4/heparin complex antibody by enzyme-linked immunosorbent assay revealed to us that our patient had developed HIT. Instead of heparin, we used nafamostat mesilate (NM) as an anticoagulant during hemodialysis, but could not completely prevent HIT-induced thrombocytopenia or clot formation in the extracorporeal circuit. Combined use of NM and aspirin completely inhibited platelet aggregation, decrease in platelet count and clot formation in the extracorporeal circuit.

Optically stimulated luminescence in an imaging plate using BaFi:Eu.

BaFI:Eu phosphors are fabricated using a new method of synthesis: liquid phase synthesis, in which the phosphor particles are formed through the association of Ba2+ ions, F-ions and Eu2+ ions in solution. An intense optically stimulated luminescence (OSL) peak at about 410 nm is observed by stimulating X ray irradiated BaFI:Eu phosphor with about 550-750 nm light. It is found that the peak wavelength of the optically stimulation spectrum is about 690 nm. This result suggests that the semiconductor laser can be used as the stimulating light source. It is also found that the OSL intensity is increased with increasing the X ray dose. The BaFI:Eu phosphor as a photostimulable material for the imaging plate of a computed radiography system provides the following advantages; (1) high X ray absorption coefficient, (2) high monodispersion in size which would contribute to sharp images, (3) high OSL and thus low luminescence mottle and (4) high DQE (detective quantum efficiency).

Cellular component of vascular calcification. Fibroblasts are essential for calcium deposition in cultured cells.

It has been reported that calcium deposition and calcium content in cultured human aortic smooth muscle cells (SMC) increased when the cells are incubated in a medium with a high phosphate concentration (2 mM). To determine the cellular components or soluble factors contributing to the deposition, we cultured commercially available SMC, fibroblasts (Fb) and endothelial cells (Ed). These cells and their mixtures were incubated for 10 days in normal or high-phosphate media. Calcium crystals were stained by the von-Kossa staining and counted in the defined area. Calcium content was measured by a colorimetric assay. SMC were incubated in high-phosphate media (up to 2 mM) or beta-glycerophosphate (beta-GP) media, resulting in no obvious deposition of calcium crystals, irrespective of the coating of type I collagen on the dish. Next, various combinations of cells were cultured, and a significant number of depositions were observed only when Fb were included in the combination. The calcium content was significantly higher in cultures of SMC and Fb. The calcium deposition on single or mixture of the cells did not increase compared with control when cells were incubated in a high concentration of phosphate, cultured in the existence of beta-GP or uremic serum. We therefore conclude that Fb, rather than SMC or Ed, are essential for calcium deposition and calcium accumulation in culture. Phosphate concentration in the medium and uremic serum did not influence the deposition of calcium.

Effect of ticlopidine hydrochloride on erythropoietin-induced rise in blood pressure in patients on maintenance hemodialysis.

BACKGROUND/AIMS: A recent observation that antiplatelet-aggregation drugs, including ticlopidine hydrochloride, may prevent erythropoietin (EPO)-induced rise in blood pressure in hemodialysis (HD) patients remains a subject of particular interest. The aim of the present study was to determine the effect of ticlopidine hydrochloride on EPO-induced rise in blood pressure of HD patients with special reference to blood levels of vasoactive substances. METHODS: HD patients who showed hypertension or aggravation of preceding hypertension with EPO treatment were selected for this study. Ticlopidine hydrochloride was administered at a dose of 200 mg daily for 4 weeks. Blood pressure and serum levels of nitric oxide (NO), atrial natriuretic peptide (ANP) and endothelin (ET) were determined before and after drug administration. Patients were divided into two groups, one of which showed a drop in mean blood pressure (MBP) of >10 mm Hg (group I) and one which did not (group II), and a comparison was made between them with respect to the blood parameters. RESULTS: Five of 15 patients showed a drop of MBP of >10 mm Hg (group I), and 10 patients did not show any change in MBP (group II). In group I, there was a significant increase in blood NO levels compared to the concentrations before ticlopidine administration, while there was no change in group II. With respect to ANP and ET, there was no significant change in either of the groups. CONCLUSION: The findings suggest that the preventive effect of ticlopidine hydrochloride on EPO-induced rise in blood pressure may partly be related to the enhancement of NO production in patients on maintenance HD.

Changes in osteoprotegerin and markers of bone metabolism during glucocorticoid treatment in patients with chronic glomerulonephritis.

It is well known that long-term glucocorticoid treatment causes osteoporosis, but the precise mechanism remains unclear. Recently, osteoprotegerin (OPG) has been identified as a cytokine that inhibits osteoclast differentiation. We have previously demonstrated that serum OPG is suppressed by glucocorticoids. Therefore, the present study was carried out to clarify the interrelationships between OPG and other markers of bone metabolism during glucocorticoid treatment. Thirteen patients (7 men, 6 women; 44.1 +/- 5.9 years old) with chronic glomerulonephritis who were to be treated with glucocorticoids for the first time were chosen for this study. Markers of bone metabolism, including serum OPG, osteocalcin (OC), bone-specific alkaline phosphatase activity (bAP), parathyroid hormone (PTH), tartrate-resistant acid phosphatase (TRAP), and bone mineral density (BMD), were measured before and during the treatment period. Glucocorticoids significantly reduced BMD of the lumbar spine in the 6 month treatment period (p < 0.01). Serum OPG was decreased significantly by glucocorticoids within 2 weeks (p < 0.001), and serum TRAP, a marker of bone resorption, was markedly increased (p < 0.001). On the other hand, there were no remarkable changes in serum PTH. Serum OC and bAP, markers of bone formation, were transiently reduced during the treatment period (p < 0.01). Furthermore, only serum OPG was positively and independently correlated with percentage BMD of age-matched reference (%AMR). These findings imply that glucocorticoid-induced bone loss develops rapidly via enhanced bone resorption and suppressed bone formation. Moreover, the increased bone resorption caused by glucocorticoids may be, at least in part, mediated by inhibition of OPG, not increment of PTH.