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.

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.

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.

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.

Concentrating defect in the adrenalectomized rat. Abnormal vasopressin-sensitive cyclic adenosine monophosphate metabolism in the papillary collecting duct.

Among other defects in water metabolism, adrenal insufficiency is associated with an inability to concentrate urine maximally in both man and experimental animals. Recent studies in the rabbit cortical collecting tubule have suggested indirectly that this defect may result from impaired cyclic AMP (cAMP) formation in response to antidiuretic hormone stimulation. In the present study, we examined key elements of arginine vasopressin (AVP)-dependent cAMP metabolism in the papillary collecting duct (PCD), microdissected from 8-d adrenalectomized (ADX) and sham-operated control rats. AVP-sensitive adenylate cyclase (ADC) activity in PCD did not differ between control and ADX rats. cAMP-phosphodiesterase activity (cAMP-PDIE), measured at 10(-6) M cAMP substrate concentration, was significantly higher (delta + 31.6%) in PCD of ADX rats compared with controls. Incubation of intact PCD from ADX rats with AVP resulted in an accumulation of cAMP (delta - 48.5%) significantly lower than observed in control PCD. Chronic administration of dexamethasone reduced cAMP-PDIE activity in PCD of ADX rats to levels close to or below those observed in control rat PCD, and also resulted in a restoration of AVP-stimulated cAMP accumulation to levels approaching control values. Results indicate that the impaired maximal urinary concentrating ability associated with adrenal insufficiency may be due, at least in part, to a reduced accumulation of cAMP in response to AVP in the PCD. This decreased cAMP accumulation results from increased cAMP-PDIE activity in the PCD of ADX rats and can be corrected by administration of glucocorticoid.

Pathogenesis of nephrogenic diabetes insipidus due to chronic administration of lithium in rats.

A polyuric syndrome with nephrogenic diabetes insipidus (NDI) is a frequent consequence of prolonged administration of lithium (Li) salts. Studies in the past, mainly the acute and in vitro experiments, indicated that Li ions can inhibit hydroosmotic effect of [8-arginine]vasopressin (AVP) at the step of cAMP generation in vitro. However, the pathogenesis of the NDI due to chronic oral administration of low therapeutic doses of Li salts is not yet clarified. We conducted a comprehensive study to clarify the mechanism by which Li administered orally for several weeks induces polyuria and NDI in rats. Albino rats consuming a diet which contained Li (60 mmol/kg) for 4 wk developed marked polyuria and polydipsia; at the end of 4 wk the plasma Li was 0.7 +/- 0.09 mM (mean +/- SEM; n = 36). Li-treated rats had a significantly decreased (-33%) tissue osmolality in papilla and greatly reduced cortico-papillary gradient of urea (cortex--43%; medulla--64%; papilla--74%). Plasma urea was significantly (P less than 0.001) lower in Li-treated rats (5.4 +/- 0.2 mM) compared with controls (6.8 +/- 0.3 mM). Medullary collecting tubules (MCT) and papillary collecting ducts (PCD) microdissected from Li-treated animals had higher content of protein than MCT and PCD from the control rats. The cAMP accumulation in response to AVP added in vitro was significantly (delta = -60%) reduced. Also, the cAMP accumulation in MCT and PCD after incubation with forskolin was markedly lower in Li-treated rats. Addition of 0.5 mM 1-methyl,3-isobutyl-xanthine did not restore the cAMP accumulation in response to AVP and forskolin in MCT from Li-treated animals. In collecting tubule segments from polyuric rats with hypothalamic diabetes insipidus (Brattleboro homozygotes) the AVP-dependent cAMP accumulation was not diminished. The activity of adenylate cyclase (AdC) in MCT of Li-treated rats, both the basal and the activity stimulated by AVP, forskolin, or fluoride, was significantly (delta approximately equal to -30%) reduced, while the activity of cAMP phosphodiesterase (cAMP-PDIE) in the same segment showed no significant difference from the controls. Also, the content of ATP in MCT microdissected from Li-treated rats and incubated in vitro did not differ from controls. The rate of [14C]succinate oxidation to 14CO2 in MAL was inhibited (-77%) by 1 mM furosemide, which indicates that this metabolic process is coupled with NaCl cotransport in MAL. The rate of (14)CO(2) production from [14C]succinate in MAL was not significantly different between control and Li-treated rats. In MCT of control rats, the rate of [14C]succinate oxidation was approximately 3 times lower than in MAL. The rate of (14)CO(2) production from [(14)C]succinate in MCT of Li-treated rats was significantly (delta +33%) higher than in MCT dissected from control rats. Based on these results, we conclude that at least two factors play an important role in the pathogenesis of NDI consequent to chronic oral administration of Li: (a) decreased ability of MCT and PCD to generate and accumulate cAMP in response to stimulation by AVP; this defect is primarily due to diminished activity of AdC in these tubular segments caused by prolonged exposure to Li; and (b) lower osmolality of renal papillary tissue, due to primarily to depletion of urea, which decreases osmotic driving force for water reabsorption in collecting tubules. On the other hand, NaCI reabsorption in MAL is apparently not affected by chronic Li treatment.

Chlorpropamide action on renal concentrating mechanism in rats with hypothalamic diabetes insipidus.

To determine vasopressin (VP)-potentiating effect of chlorpropamide (CPMD), we studied the effect of CPMD in vivo and in vitro in kidneys and in specific tubule segments of rats with hypothalamic diabetes insipidus, homozygotes of the Brattleboro strain (DI rats). Rats on ad lib. water intake were treated with CPMD (20 mg/100 g body wt s.c. daily) for 7 d. While on ad lib. water intake, the urine flow, urine osmolality, urinary excretion of Na +, K +, creatinine, or total solute excretion did not change. However, corticopapillary gradient of solutes was significantly increased in CPMD-treated rats. Higher tissue osmolality was due to significantly increased concentration of Na +, and to a lesser degree urea, in the medulla and papilla of CPMD-treated rats. Consequently, the osmotic gradient between urine and papillary tissue of CPMD-treated rats (delta = 385 +/- 47 mosM) was significantly (P less than 0.001) higher compared with controls (delta = 150 +/- 26 mosM). Minimum urine osmolality after water loading was higher in CPMD-treated DI rats than in controls. Oxidation of [14C]lactate to 14CO2 coupled to NaCl cotransport was measured in thick medullary ascending limb of Henle's loop (MAL) microdissected from control and CPMD-treated rats. The rate of 14CO2 production was higher (delta + 113% +/- 20; P less than 0.01) in CPMD-treated MAL compared with controls, but 14CO2 production in the presence of 10(-3) M furosemide did not differ between MAL from control and from CPMD-treated rats. These observations suggest that CPMD treatment enhances NaCl transport in MAL. Cyclic AMP metabolism was analyzed in microdissected MAL and in medullary collecting tubule (MCT). MCT from control and from CPMD-treated rats did not differ in the basal or VP-stimulated accumulated of cAMP. The increase in cAMP content elicited by 10(-6) M VP in MAL from CPMD-treated rats (delta + 12.0 +/- 1.8 fmol cAMP/mm) was significantly (P less than 0.02) higher compared with MAL from control rats (delta + 5.1 +/- 1.0 fmol cAMP/mm). Preincubation of MAL dissected from Sprague-Dawley rats with 10(-4) M CPMD in vitro increased cAMP accumulation in the presence of VP, but no such enhancement was found in preincubated MCT. Adenylate cyclase activity, basal or stimulated by VP, 5'guanylimidodiphosphate, or by NaF, assayed in isotonic medium did not differ between MAL or MCT from control rats and MAL or MCT from CPMD-treated rats. When assayed in hypertonic medium (800 mosM), the adenylate cyclase activity in the presence of 10(-6) M VP was significantly higher in MAL of CPMD-treated rats. MAL and MCT from control and CPMD-treated rats did not differ in the activities of cAMP phosphodiesterase. The rate of [(14)C]prostaglandin E2 by medullary and papillary microsomes was not different between the control and CPMD-treated rats; likewise, there was no difference in accumulation of immunoreactive prostaglandin E2 in the medium of in vitro incubated medullary or papillary slices prepared from control and CPMD-treated rats. Based on the findings recounted above, we propose a hypothesis that CPMD administration enhances the antidiuretic effect of VP, primarily by increasing medullary and papillary tonicity dye to increased NaCl reabsorption in MAL. There is no evidence that CPMD sensitizes collecting tubules to the action of VP, at least at the camp-generation step. Therefore, increased antidiuretic response to VP in the kidneys of CPMD-treated DI rats is due to enhanced osmotic driving force for water reabsorption (lumen-to-interstitium osmotic gradient) in collecting tubules, rather than due to increased VP-dependent water permeability of tubular epithelium.

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.

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.

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.

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.

Production of renin, angiotensin II, and aldosterone by adrenal explant cultures: response to potassium and converting enzyme inhibition.

The existence of renin in a number of extrarenal tissues has been well documented, but the physiological role of extrarenal renin remains unknown. To study the physiological role of adrenal renin, we developed a serum-free culture system for adrenal capsular/zona glomrulosa explants. Explants showed good viability in culture (greater than 80%), and demonstrated net production of aldosterone, angiotensin II, and prorenin. Aldosterone production was consistently stimulated by an increase in potassium (6 mM) in the culture medium. Both aldosterone and angiotensin II production could be attenuated by adding the angiotensin converting enzyme inhibitor lisinopril to the culture medium (0.1 mM). These data suggest that rat adrenal explants are capable of producing all of the components of a functional renin-angiotensin-aldosterone system and that these components can interact in response to physiological stimuli. These findings support the hypothesis that a local adrenal renin system may play a physiological role in the control of adrenal aldosterone production.

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.

Arginine vasopressin inhibits interleukin-1 beta-stimulated nitric oxide and cyclic guanosine monophosphate production via the V1 receptor in cultured rat vascular smooth muscle cells.

BACKGROUND: It has been reported that various vasoactive substance modulate cytokine stimulated nitric oxide (NO) production in many cell types. OBJECTIVE: To examine the effects of arginine vasopressin (AVP) on the production of NO and cyclic GMP (cGMP), and on inducible nitric oxide synthase (INOS) in cultured rat vascular smooth muscle cells (VSMC). DESIGN: Because VSMC possess the V1 receptor which clauses vascular contraction and respond to various cytokines for producing NO, we used rat VSMC and selected interleukin-1 beta (IL-1 beta) as a potent stimulator of NO production among various cytokines. We also measured cGMP production, which is the final mediator of NO-induced vascular relaxation, in order to evaluate the physiologic meaning of the present study. METHODS: VSMC were incubated with test agents for 24 h except for a time-course study. Nitrite as a stable end product of NO was measured in the medium. Intracellular cGMP contents were assayed by enzyme immunoassay. INOS messenger RNA expression was analyzed by Northern blotting. RESULTS: AVP inhibited IL-1 beta-induced nitrite production in a dose- and time-dependent manner with concomitant changes in intracellular cGMP contents. On the other hand, AVP did not affect nitrite and cGMP production in the absence of IL-1 beta. Inhibition of nitrite and cGMP production by AVP was reversed by administration of the specific V1 receptor antagonist [1-(beta-mercapto-beta,beta- cyclopentamethylene propionic acid), 2-(O-methyl)-tyrosine] -Arg8-vasopressin) but not by the oxytocin (OXT) receptor antagonist [d(CH2(5)), TyrMe2, Orn8]-Vasotocin. Administration of the V1 receptor antagonist or OXT receptor antagonist alone did not affect IL-1 beta-stimulated nitrite and cGMP production. Although administration of AVP inhibited IL-1 beta-induced INOS messenger RNA expression, administration of the V1 receptor antagonist but not of the OXT receptor antagonist reversed this inhibition. CONCLUSION: It is suggested that AVP inhibits IL-1 beta-induced NO and cGMP production via the V1 receptor but not via the OXT receptor in VSMC. AVP can cause vascular contraction not only through direct action but also through indirect action by inhibiting NO production under some inflammatory conditions.

Involvement of erythropoietin-induced cytosolic free calcium mobilization in activation of mitogen-activated protein kinase and DNA synthesis in vascular smooth muscle cells.

BACKGROUND/OBJECTIVE: Human recombinant erythropoietin (rHuEPO) induces cytosolic free calcium ([Ca2+]i) mobilization, an activation of mitogen-activated protein (MAP) kinase and DNA synthesis in several tissues. We explored the mechanism of rHuEPO-induced [Ca2+]i mobilization and its role in the activation of MAP kinase and DNA synthesis in vascular smooth muscle cells (VSMC). METHODS: [Ca2+]i concentrations were measured by fura-2. MAP kinase activation was analyzed using an immunocomplex kinase assay and Western blotting. DNA synthesis was measured as an incorporation of 5-bromo-2'-deoxyuridine. RESULTS: Although addition of rHuEPO significantly increased [Ca2+]i, either in the presence or absence of extracellular Ca2+, the peak level and sustained elevation of [Ca2+]i were significantly reduced in the absence of extracellular Ca2+. Pretreatment with genistein completely blocked the elevation of [Ca2+]i in both conditions. Calphostin C and staurosporine did not completely block the elevation of [Ca2+]i. Staurosporine reduced its peak level in a dose-dependent manner, whereas calphostin C reduced its peak level at concentrations over 1 nmol/l in the presence of extracellular Ca2+. Similar results to those with staurosporine were observed with nifedipine. In the absence of extracellular Ca2+, their dose-dependent effects disappeared even though rHuEPO increased [Ca2+]i. rHuEPO activated MAP kinase and DNA synthesis, both of which were significantly suppressed by the chelation of intracellular Ca2+. CONCLUSION: These findings suggest that rHuEPO increases [Ca2+]i by both Ca2+ influx and Ca2+ release from intracellular stores. Tyrosine phosphorylation is critical in the regulation of [Ca2+]i, but protein kinase C activation is important only in the regulation of Ca2+ influx. Dihydropyridine-sensitive L-type Ca2+ channels seem to be involved in rHuEPO-induced Ca2+ influx. In addition, increase of [Ca2+]i by rHuEPO stimulates MAP kinase activation and DNA synthesis in VSMC.

The effect of erythropoietin on interleukin-1beta mediated increase in nitric oxide synthesis in vascular smooth muscle cells.

OBJECTIVE: Recently, we observed that recombinant human erythropoietin (rHuEPO) inhibits the interleukin (IL)-1beta induced nitric oxide (NO) production and inducible NO synthase (iNOS) expression in cultured rat vascular smooth muscle cells (VSMC). The mechanisms of these inhibitory effects of rHuEPO were evaluated. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was performed to identify a specific erythropoietin receptor (EpoR). Tyrosine phosphorylation of phospholipase C (PLC) was analyzed by combination of immunoprecipitation and Western blotting. Protein kinase C (PKC) activities were analyzed by phosphorylation assay of myelin basic protein (MBP4-14). VSMC were incubated with test agents for 24 h and nitrite as a stable NO metabolite was measured. iNOS mRNA and protein expression was analyzed by Northern and Western blotting, respectively. RESULTS: RT-PCR analysis revealed that EpoR m-RNA was expressed; furthermore, it might be alternatively spliced in VSMC. rHuEPO induced tyrosine phosphorylation of PLC-gamma1 and activation of PKC. rHuEPO inhibited not only IL-1beta induced nitrite production, but also the expression of iNOS mRNA and protein. These inhibitory effects of rHuEPO were reversed in the presence of PKC inhibitors, calphostin C (1 pmol/l) or staurosporine (10 nmol/l). PKC activation by phorbol myristate acetate inhibited nitrite production. The inhibitory effect of rHuEPO on IL-1beta induced nitrite production was also eliminated in PKC depleted cells or in the existence of anti-EpoR antibody. CONCLUSION: rHuEPO inhibits IL-1beta induced NO production by suppressing iNOS mRNA and protein expressions through EpoR, and the PLC-gamma1 and PKC pathway may be involved.

Immunotactoid glomerulopathy characterized by steroid-responsive massive subendothelial deposition.

We report a case of immunotactoid glomerulopathy with unique histologic findings in serial biopsies. A 73-year-old man complained of developing general edema. Laboratory data on admission presented moderate renal dysfunction with nephrotic syndrome. There was no evidence of systemic disease that might cause secondary glomerulopathy. Light microscopy of the renal specimen revealed lobulation of glomerular tufts and massive endothelial deposition of hyaline-like periodic acid-Schiff-positive substance with neutrophilic infiltration. The deposits were positive for immunoglobulin by immunohistochemical stains but negative for Congo red stain. Electron microscopy disclosed the deposition of microtubular structure (60 nm in diameter) predominantly in the subendothelial area and to some extent in the subepithelial and mesangial areas. Some of the tubules were extremely large (100 to 130 nm in diameter) and displayed a unique scroll structure in cross-section. The patient was treated with two sessions of plasma exchange and subsequent oral prednisolone (30 mg/d). Proteinuria and renal dysfunction improved significantly in the following 2 months. Second and third renal biopsies revealed disappearance of the deposit along with the improvement of proteinuria and renal dysfunction. Because similar microtubular structures were found in neutrophils in the glomerulus as well as in the urinary sediment, phagocytosis was suggested as a possible mechanism for removal of the deposit.