A case of proliferative glomerulonephritis with immunoglobulin A1-lambda deposits successfully treated by chemotherapy

A 74-year-old man presented with nephrotic syndrome and kidney insufficiency. Laboratory tests revealed monoclonal gammopathy of immunoglobulin A-lambda. Renal biopsy revealed diffuse mesangial proliferation and double-contoured basement membranes. Immunofluorescent analyses showed granular deposition of immunoglobulin A and C3 at the capillary walls and mesangial regions. Immunohistochemistry suggested monoclonal deposition of immunoglobulin A1-lambda. Electron microscopic analyses showed finely granular electron-dense deposits at mesangial and subendothelial areas. These findings suggested immunoglobulin A-type proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Based on the results of bone marrow aspiration, multiple myeloma was diagnosed. Because the renal manifestation was considered to be affected by monoclonal gammopathy, chemotherapy was initiated rather than immunomodulatory therapy. Although bortezomib and dexamethasone proved ineffective, second chemotherapy with elotuzumab, lenalidomide, and dexamethasone was successful, and kidney function recovered. Effective treatments for proliferative glomerulonephritis with monoclonal immunoglobulin deposits have not been established. This represents the first description of a patient successfully treated for proliferative glomerulonephritis with monoclonal immunoglobulin deposits by chemotherapy using elotuzumab.

Hyponatremia associated with demyelinating disease of the nervous system

A 63-year-old man was diagnosed with periodontitis and underwent tooth extraction. Several days later, he suffered a high fever, ischuria, a change in personality, and disorientation. A urologist examined him and found severe hyponatremia (117 mEq/L), and he was then transferred to our hospital. On admission, physical findings revealed dysfunction of the bladder and bowel, altered mental status, and hypovolemia. Blood chemistry showed serum sodium of 120 mEq/L, a serum urate of 1.4 mg/dL, urinary Na of 61 mEq/L, and fractional urate excretion of 16 %. Examination of the cerebrospinal fluid (CSF) showed monocytosis. Magnetic resonance imaging (MRI) of the brain and spinal cord showed multiple lesions characterized by hyperintensity on T2-weighted sequences, suggesting demyelinating disease. His sodium concentration normalized 3 days after volume replacement therapy, and his altered mental status along with the dysfunction of the bladder and bowel were promptly improved after the initiation of high-dose glucocorticoids. Additionally, the abnormal lesions on MRI markedly decreased. This clinical course led to the likely diagnosis of acute disseminated encephalomyelitis (ADEM). Hyponatremia in neurologically injured patients is usually attributed to the syndrome of inappropriate antidiuretic hormone (SIADH) or cerebral salt-wasting syndrome (CSWS). In the present patient, the uric acid level remained low and uric acid excretion remained elevated despite correction of the hyponatremia, which suggested CSWS. The differentiation of CSWS from SIADH is difficult but critically important due to the fact that the disorders are managed differently. Coexistence of ADEM and CSWS has rarely been reported.

[A case of crescentic poststreptococcal acute glomerulonephritis (PSAGN) accompanied by membranous nephropathy]

In 2010, a 71-year-old man was referred to our hospital because of mild proteinuria and hematuria. At that time, he had been asymptomatic. Three months later he noticed macroscopic hematuria, followed by general malaise, and then anorexia. He was admitted for acute kidney injury (serum creatinine 2.7 mg/dL), marked proteinuria (4.35 g/gCr), and elevated C-reactive protein (7.21 mg/dL). Some vesicles were noted on the soft palate, and a throat culture yielded a growth of group A beta-hemolytic streptococci. Antistreptolysin O and antistreptokinase titers were elevated, but serum complement levels were within normal limits. Antineutrophil cytoplasmic antibodies (ANCA) directed against elastase and bactericidal permeability increasing protein (BPI)were positive. The renal function and inflammation did not improve despite oral antibiotic therapy. Pathological examination of a renal biopsy specimen revealed diffuse crescent formation, numerous subepithelial dome-shaped deposits (humps), and prominent endocapillary proliferation. Furthermore, a focal and segmental spike appearance was seen, with deposits smaller than humps. There was a striking clinical improvement after steroid pulse therapy followed by oral prednisolone. The features of this case strongly suggest crescentic PSAGN accompanied by pre-existing membranous nephropathy.

[A case of drug-induced granulomatous interstitial nephritis during the long course of Crohn's disease]

A 33-year-old man was diagnosed with Crohn's disease in 2001, and treated with mesalazine and ranitidine. Administration of infliximab was started in 2007 and led to a decrease in the activity of the Crohn's disease. He was referred to our department in the summer of 2011 following rapid progression of renal insufficiency, with serum creatinine levels increasing from 1.5 mg/dL to 4.3 mg/dL within 2 months. On admission, laboratory findings showed signs of inflammation, anemia, proteinuria, and hematuria. Renal biopsy results indicated the diagnosis of granulomatous interstitial nephritis. Neither clinical manifestations nor laboratory findings were suggestive of infectious disease, sarcoidosis, Wegener's granulomatosis or tubulointerstitial nephritis and uveitis. Mesalazine and ranitidine were discontinued in view of reports of drug-induced granulomatous interstitial nephritis. Levels of C-reactive protein immediately decreased, but renal function remained unimproved. Treatment with steroid pulse therapy was then initiated, followed by oral prednisolone at 40 mg/day, and his serum creatinine recovered to 2.3 mg/dL. Mesalazine and/or ranitidine appear to have been responsible for the granulomatous interstitial nephritis. In cases of Crohn's disease showing rapid deterioration of renal function, drug-induced renal disease should be considered, even if the drugs have been taken without apparent problems for a long duration.

[Clinical characteristics of adult-onset minimal change nephrotic syndrome in our hospital]

OBJECTIVE

Few findings are available regarding adult-onset minimal change nephrotic syndrome (MCNS) with respect to the disease course and complications, such as acute kidney injury (AKI). We therefore performed a retrospective review to characterize the clinical presentations, steroid responsiveness and complications of adult-onset MCNS patients in our hospital.

PATIENTS AND METHODS

We retrospectively reviewed 40 cases of idiopathic adult-onset MCNS who had been investigated and treated at a single center. Patients between 18 and 50 years of age (Younger group) at the time of biopsy were compared with those older than 50 years (Older group) with regard to demographic data, clinical features and treatment outcome.

RESULTS

Baseline characteristics of the 40 patients were: median age, 42 years (interquartile range: 28-63 years); male, 70%; mean (+/- standard deviation) systolic and diastolic blood pressures, 125 +/- 17 mmHg and 78 +/- 12 mmHg, respectively; estimated glomerular filtration rate (eGFR), 74 mL/min/1.73 m2 (range: 64-94 mL/min/1.73 m2); serum albumin, 1.8 +/- 0.3 g/dL; and urinary protein, 7.8 g/day (range: 3.9-10.4 g/day). All except for one patient received steroid pulse therapy. Time to complete response (CR) was 12 days (range: 8-21 days). Time to CR was significantly longer in the Older group (p = 0.011). The Late-responder group (time to CR > 2 weeks)was significantly older (p < 0.01), with a low eGFR (p < 0.001) and a higher prevalence of interstitial fibrosis in renal biopsy before the initiation of corticosteroid therapy (p < 0.05), compared with the Early-responder group. AKI was observed in 14 patients. Patients with an episode of AKI were significantly older (p = 0.005), with a lower eGFR (p < 0.002) and a higher prevalence of cellular casts (p < 0.05). At the follow-up, 19 patients (51%) had experienced relapses. The relapse rate was significantly lower in the Older group than in the Younger group (p < 0.05).

CONCLUSION

The present study revealed that older patients had a longer period to CR and a higher risk of AKI at follow-up.

[Case of mixed connective tissue disease complicated with sarcoidosis and central diabetes insipidus]

In 2003, a 64-year-old woman was diagnosed with mixed connective tissue disease and treated with oral prednisolone (30 mg/day). The prednisolone dose was gradually decreased, and a dose of 5 mg/day had been maintained since 2004. In 2009, she gradually developed vision loss, malaise, anorexia, and throat pain due to hydrodipsia. She was noted to have iritis and vitreous opacity by an ophthalmologist, and was referred for further evaluation. Fine rales were audible throughout the entire lung field, and chest CT showed diffuse small nodules that were more prominent on the upper and middle lobes, and swelling of the mediastinal and hilar lymph nodes. Transbronchial lung biopsy showed many epithelioid granulomas with multinuclear giant cells, compatible with sarcoidosis. Polyuria was identified as a cause of hydrodipsia and a diagnosis of partial central diabetes insipidus was made. High-dose prednisolone (40 mg/day) together with intranasal administration of desmopressin resulted in improvement of all of her clinical symptoms. MCTD followed by sarcoidosis is rare. Furthermore, this is the first reported case of MCTD complicated by sarcoidosis and central diabetes insipidus.

Azelnidipine-induced chyloperitoneum in a patient with microscopic polyangiitis

A 76-year-old man developed fever and appetite loss, and then was referred to our hospital because of rapidly progressive renal insufficiency; his serum creatinine increased from 1.2 to 5.9 mg/dl within 1 month. On admission, his blood pressure was 166/92 mmHg, and laboratory findings showed signs of inflammation, anemia, proteinuria, and hematuria. Chest computed tomography (CT) suggested interstitial pneumonia, while a renal biopsy revealed that small arteries and arterioles were affected, and there was pauci-immune glomerulonephritis with cellular and fibrocellular crescents. In addition, an increased myeloperoxidase antineutrophil cytoplasmic antibody titer confirmed microscopic polyangiitis. Treatment with oral prednisolone was initiated and seemed to successfully resolve the vasculitis activity. On the 11th day of admission, a calcium channel blocker, azelnidipine, was added to treat hypertension. Two days later, the patient developed abdominal distension, and abdominal CT showed massive ascites. The ascitic fluid was a milky white transudate with a normal leukocyte count. Neither clinical manifestations nor laboratory findings suggestive of liver cirrhosis, malignancy, infectious peritonitis, or bowel perforation were observed. On the 18th day of admission, azelnidipine was discontinued in view of reports of calcium channel blocker-induced chyloperitoneum in patients undergoing peritoneal dialysis. Immediately, the abdominal distension disappeared, and the ascites appeared to decrease. Azelnidipine appears to have been responsible for the chyloperitoneum. Since a few cases of secondary vasculitis developing chyloperitoneum have been previously reported, vasculitis may have played a role in the development of chyloperitoneum.

Successful treatment of HCV-related cryoglobulinemic glomerulonephritis with double-filtration plasmapheresis and interferon combination therapy

A 67-year-old, hepatitis C virus (HCV)-positive woman was admitted to our hospital because of proteinuria and leg edema. Laboratory examination showed decreased serum albumin and complement activity and positive cryoglobulin. The HCV RNA genotype was 1b with high viral load. Kidney biopsy showed membranoproliferative glomerulonephritis (MPGN) with capillary deposition of C3, IgM, and IgG, indicating HCV-associated glomerulonephritis. In addition to interferon (IFN) therapy, double-filtration plasmapheresis (DFPP) was performed to reduce HCV RNA blood levels in the early stage of IFN therapy. This treatment greatly reduced the viral load and induced clinical remission of MPGN, suggesting that DFPP plus IFN combination therapy may represent a potentially effective modality for refractory-type HCV-associated glomerulonephritis.

[Clinical characteristics of five elderly patients with severe hypokalemia induced by glycyrrhizin derivatives]

Although hypokalemia is a common clinical problem, symptoms generally do not become manifest unless the serum potassium (K) falls rapidly. We encountered five cases with symptomatic severe hypokalemia (K<2.0 mEq/L) hospitalized for the past 15 months at our hospital. We examined the clinical characteristics and treatment of these patients. All five patients were women, and their mean age was 77.8 (73-82)years. They suffered from hypertension. Mean K level at admission was 1.66 (1.4-1.9) mEq/L and HCO3(-) was 48.3 (33.6-56.1) mmol/L. Plasma aldosterone level was low and plasma rennin activity was suppressed. All patients developed progressive muscle weakness with elevated creatinine phosphokinase. Three of the patients had received Chinese medicine which contained licorice, one received glycyrrhizin and the other one had received both. We diagnosed these cases as pseudoaldosteronism induced by glycyrrhizin. With discontinuation of the drugs and intravenous as well as oral K supplementation, serum K were normalized and clinical symptoms improved within 12 days. For one patient who developed cardiac dysfunction, concentrated K solution (230 mEq/L) was infused into the central vein. These findings show that glycyrrhizin ingestion should be kept in mind as a cause of an extreme degree of an hypokalemia, especially in elderly patients.

[Adult case of severe Henoch-Schönlein purpura associated with steroid-resistant nephrotic syndrome successfully treated with intravenous cyclophosphamide]

Henoch-Schönlein purpura (HSP) is a systemic disorder characterized by small vessel vasculitis with the deposition of IgA immune complexes. Renal involvement is the major cause of morbidity and mortality in patients with HSP. We report here a 37-year-old female patient with HSP nephritis (HSPN) associated with steroid-resistant nephrotic syndrome and renal dysfunction despite conventional therapy. The patient was successfully treated with intravenous cyclophosphamide following treatment with intravenous pulse methylprednisolone and oral prednisolone. The combination therapy resulted in a significant decrease in proteinuria, together with improvement of renal function. The patient finally reached a stage of clinical remission.

[Case of scleroderma with rapid progressive glomerulonephritis associated with both MPO-ANCA and anti-GBM antibodies]

A 66-year-old male with scleroderma developed rapidly progressive glomerulonephritis (RPGN). Renal pathology revealed crescentic glomerulonephritis with interstitial inflammation and fibrosis. Immunofluorescent micrography showed linear deposition of IgG along the glomerular capillary wall. Both anti-glomerular basement membrane antibody (anti-GBM Ab), and myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) were detected by an enzyme-linked immunosorbent assay (ELISA). These findings were compatible with ANCA-related vasculitis and anti-GBM Ab nephritis. Laboratory findings showed rapid elevation of the serum creatinine level (5.9 mg/dL), and a high titer of MPO-ANCA (530 EU) and anti-GBM Ab (21 EU). He was started on methylprednisolone pulse therapy and temporary hemodialysis. Since the immunosuppressive therapy lowered both antibody titers steadily and improved renal function, hemodialysis was discontinued 4 weeks after the therapy. It has been reported that some scleroderma patients developed rapid progressive glomerulonephritis due to ANCA-associated vasculitis in addition to the typical scleroderma renal crisis. There have been few reports of a scleroderma patient associated with RPGN, in whom both MPO-ANCA and anti GBM antibodies were detected.

Smooth muscle alpha-actin deficiency in myofibroblasts leads to enhanced renal tissue fibrosis

Myofibroblasts are a major source of proinflammatory cytokines and extracellular matrix in progressive tissue fibrosis leading to chronic organ failure. Myofibroblasts are characterized by de novo expression of smooth muscle alpha-actin (SMalphaA), which correlates with the extent of disease progression, although their exact role is unknown. In vitro cultured myofibroblasts from kidney of SMalphaA knock-out mice demonstrate significantly more prominent cell motility, proliferation, and type-I procollagen expression than those of wild-type myofibroblasts. These pro-fibrotic properties are suppressed by adenovirus-mediated SMalphaA re-expression, accompanied by down-regulation of focal adhesion proteins. In interstitial fibrosis model, tissue fibrosis area, proliferating interstitial cell number, and type-I procollagen expression are enhanced under SMalphaA deficiency. In mesangioproliferative glomerulonephritis model, cell proliferation in the mesangial area is also enhanced in SMalphaA knock-out mice. Adenoviral SMalphaA introduction into renal interstitium obviously ameliorates tissue fibrosis in interstitial fibrosis model. These results indicate that SMalphaA suppresses the pro-fibrotic properties of myofibroblasts, highlighting the significance of smooth muscle-related proteins in moderating chronic organ fibrosis under pathological conditions.

[Cerebral salt wasting syndrome in a patient with viral meningoencephalitis]

A 53-year-old male was admitted to our hospital for a high fever. He suffered a change in personality, memory loss and disorientation as well. The findings of cerebrospinal fluid showed monocytosis, but the titers of glucose, C1 and ADA were all normal. Although there was no bacterium in the CSF, the patient's electroencephalography finding was abnormal. We diagnosed his condition as viral meningoencephalitis and started treatment with antiviral agents. Blood chemistry showed serum sodium of 130 mEq/l and plasma osmolarity was reduced to 272 mOsm/kg, while urine osmolarity was high at 353 mOsm/kg. Two potential causes of hyponatremia in this patient were the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) or cerebral salt wasting syndrome (CSWS). Physical findings revealed a contracted extracellular fluid volume, strongly suggesting the presence of CSWS. The massive urine sodium loss overcoming sodium intake supported this diagnosis. After treatment with vigorous sodium and volume replacement for over 4 weeks, hyponatremia as well as meningoencephalitis were improved without any complication. To the best of our knowledge, this is the first report on CSWS in a patient with viral meningoencephalitis.

CCAAT/Enhancer-binding protein delta contributes to myofibroblast transdifferentiation and renal disease progression

Myofibroblasts are pivotal participants in pathologic processes in a wide variety of organs, such as lung, liver, and kidney, by producing several inflammatory cytokines and extracellular matrices. The mechanism by which transdifferentiation from original cell to myofibroblast occurs, however, is still unclear. The expression of smooth muscle alpha-actin (SMalphaA) is the most characteristic feature of myofibroblasts; therefore, it was speculated that any factors that promote SMalphaA expression might be the key to transdifferentiation to myofibroblasts and disease exacerbation. A transcription factor CCAAT/enhancer-binding protein delta (C/EBPdelta) was identified and demonstrated to bind to sequences including the CArG motif from SMalphaA intron 1 and to increase transcriptional activity of this promoter. Expression of SMalphaA and C/EBPdelta in the glomerular area was upregulated in rat anti-Thy1 glomerulonephritis and mouse Habu-venom glomerulonephritis, both of which are models of mesangioproliferative glomerulonephritis. In the latter model, C/EBPdelta knockout mice demonstrated significantly less SMalphaA expression in the glomerular area on day 8 and less renal functional deterioration on day 14, compared with wild-type mice. These data suggest an important role for C/EBPdelta in myofibroblast transdifferentiation and glomerulonephritis exacerbation.

Therapeutic effect of all-trans retinoic acid on rats with anti-GBM antibody glomerulonephritis

BACKGROUND

All-trans retinoic acid (ATRA) has antiproliferative and anti-inflammatory effects and is currently used in the treatment of leukemia and dermatologic diseases. We tested the therapeutic potential of ATRA on anti-glomerular basement membrane (GBM) glomerulonephritis rats.

METHODS

Glomerulonephritis was induced in male Wistar-Kyoto rats on day 0 by an intravenous injection of antirat GBM antibody. On day 14 after the induction of anti-GBM glomerulonephritis, some rats were sacrificed (N = 5). Another 10 rats were divided into two groups: the vehicle group (N = 5) and the ATRA treated group (N = 5). ATRA was orally administrated from day 14 to day 27 after disease induction. Blood pressure, body weight, urinary protein excretion, and blood chemistry was determined on days 1, 14, 21, and 27. Kidney samples were obtained on day 28. The kidneys were examined with periodic acid-Schiff staining (PAS) and immunohistochemistry using antibodies against the proliferative cell nuclear antigen (PCNA), rat monocyte and macrophage (ED-1), and alpha-smooth muscle actin (alpha-SMA). Glomerular RNA was extracted from isolated glomeruli, and reverse transcription (RT) followed by polymerase chain reaction (PCR) was performed.

RESULTS

ATRA administration produced a 55% reduction of proteinuria in glomerulonephritis rats. Light microscopic analysis revealed severe necrosis/crescent formation (>50% of the glomerulus) affecting 34% of glomeruli in vehicle rats, whereas ATRA treatment reduced the glomeruli showing severe change to 14%. ATRA also significantly reduced PCNA-positive cells, ED-1-positive cells and alpha-SMA-positive area in the glomeruli. RT-PCR analyses revealed that a wide variety of genes including inflammation related [tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and CCAAT enhancer-binding protein delta (C/EBPdelta)], cell proliferation-related [platelet-derived growth factor (PDGF)] and fibrosis-related [transforming growth factor-beta1 (TGF-beta1), type I collagen, and alpha-SMA) genes were suppressed in the glomeruli of ATRA-treated rats.

CONCLUSION

ATRA administration significantly reduced severe necrosis/crescent formation and urinary protein excretion in glomerulonephritis rats. Suppression of a wide variety of gene expression may partly explain the mechanism of ATRA's antiproliferative and anti-inflammatory effects. These data suggest a novel therapeutic application of ATRA toward glomerulonephritis.

Prevalence and outcome of renal artery stenosis in atherosclerotic patients with renal dysfunction

We investigated the prevalence of renal artery disease and outcome in a cohort of atherosclerotic patients with renal dysfunction. We studied 44 consecutive patients who were older than 50 years of age, who had renal dysfunction and in whom one or more of the following atherosclerotic diseases was confirmed: cerebral infarction, coronary artery disease or peripheral vascular disease. Renal artery stenosis was assessed by gadolinium-enhanced magnetic-resonance angiography. Patients who were treated medically were prospectively followed up in our outpatient clinic and the impact of renal artery stenosis on survival was evaluated. Renal artery stenosis was found in 22 (50%) of the 44 patients. Difference in kidney length and carotid artery stenosis were identified as independent predictors of renal artery stenosis. Among the patients who were treated medically (n=42), rates of mortality were 4.4, 12.7 and 18.1 per 100 patient-years in those without renal artery stenosis, those with unilateral renal artery stenosis and those with bilateral renal artery stenosis, respectively. The mortality and renal survival curves were significantly different among these three groups. These findings indicate that renal artery stenosis is common in patients with renal dysfunction and concomitant cardiovascular disease, especially in those with carotid artery stenosis, and that a substantial difference in the length of kidneys may be a predictor of renovascular disease. Patients with renal dysfunction resulting from renal artery stenosis are at risk of death from cardiovascular disease and end-stage renal failure.

Y-27632 prevents tubulointerstitial fibrosis in mouse kidneys with unilateral ureteral obstruction

BACKGROUND

The small GTPase Rho is involved in cell-to-substratum adhesion and cell contraction. These actions of Rho mediated by downstream Rho effectors such as Rho-associated coiled-coil forming protein kinase (ROCK) may be partly responsible for the progression of renal interstitial fibrosis.

METHODS

The anti-fibrosis effects of Y-27632, a specific ROCK inhibitor, were studied both in vivo (unilateral ureteral obstruction; UUO) and in vitro. To investigate the therapeutic efficacy of Y-27632 in UUO kidneys, smooth muscle alpha actin (SMalphaA) expression, macrophage infiltration and fibrosis in the obstructed kidneys were studied. SMalphaA, transforming growth factor beta (TGF-beta), alpha1 (I) collagen, osteopontin, macrophage chemoattractant peptide-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) gene expression were examined by Northern blotting. To elucidate the mechanism linking the Rho-ROCK pathway with renal fibrosis, the effects of Y-27632 on in vitro cell proliferation and cell migration were studied.

RESULTS

In vivo analysis showed that Y-27632 suppressed SMalphaA expression, macrophage infiltration and interstitial fibrosis, and that Y-27632 suppressed SMalphaA, TGF-beta and alpha1 (I) collagen mRNA expression. In vitro analysis showed that Y-27632 did not suppress proliferation of renal fibroblasts but suppressed migration of macrophages.

CONCLUSIONS

The Rho-ROCK system may play an important role in the development of tissue fibrosis, and the Rho-ROCK signaling pathway may be a new therapeutic target for preventing interstitial fibrosis in progressive renal disease.

Region of heat-stable enterotoxin II of Escherichia coli involved in translocation across the outer membrane

Heat-stable enterotoxin II of Escherichia coli (STII) is synthesized as a precursor form consisting of pre- and mature regions. The pre-region is cleaved off from the mature region during translocation across the inner membrane, and the mature region emerges in the periplasm. The mature region, composed of 48 amino acid residues, is processed in the periplasm by DsbA to form an intramolecular disulfide bond between Cys-10 and Cys-48 and between Cys-21 and Cys-36. STII formed with these disulfide bonds is efficiently secreted out of the cell through the secretory system, including TolC. However, it remains unknown which regions of STII are involved in interaction with TolC. In this study, we mutated the STII gene and examined the secretion of these STIIs into the culture supernatant. A deletion of the part covering from amino acid residue 37 to the carboxy terminal end did not markedly reduce the efficiency of secretion of STII into the culture supernatant. On the other hand, the efficiency of secretion of the peptide covering from the amino terminal end to position 18 to the culture supernatant was significantly low. These observations indicated that the central region of STII from amino acid residue 19 to that at position 36 is involved in the secretion of STII into the milieu. The experiment using a dsbA-deficient strain of E. coli showed that the disulfide bond between Cys-21 and Cys-36 by DsbA is necessary for STII to adapt to the structure that can cross the outer membrane.

Fluvastatin suppresses oxidative stress and fibrosis in the interstitium of mouse kidneys with unilateral ureteral obstruction

BACKGROUND

Recently, we demonstrated increased oxidative stress in the interstitium of ureteral obstructed kidneys based on the increased expression of heme oxygenase-1 and immunohistochemical detection of advanced glycation end products (AGE) in the interstitium. Antioxidant therapy may have a therapeutic potential toward interstitial fibrosis of unilateral ureteral obstruction (UUO) kidneys. Fluvastatin is an HMG-CoA reductase inhibitor and has been demonstrated to have an antioxidant activity in vitro.

METHODS

The effects of fluvastatin on UUO kidneys from the viewpoints of antioxidant action in vivo and antifibrosis action were studied. To investigate the antioxidant action and its therapeutic efficacy of fluvastatin in UUO kidneys, AGE accumulation and fibrosis in the obstructed kidneys was compared among vehicle-, pravastatin-, or fluvastatin-treated (10 or 40 mg/kg/day) groups.

RESULTS

Tubulointerstitial fibrosis was significantly attenuated in fluvastatin-treated animals. Fluvastatin significantly suppressed the degree of immunostaining of AGE in UUO kidneys.

CONCLUSIONS

These results provide evidence for the antioxidant action of fluvastatin in vivo. The decreased interstitial fibrosis along with a decreased oxidative stress marker in the interstitial lesion strongly suggests the existence of a causal relationship between them. Fluvastatin may have therapeutic value in slowing or preventing interstitial fibrosis in progressive renal disease.

Fluvastatin suppresses oxidative stress and fibrosis in the interstitium of mouse kidneys with unilateral ureteral obstruction

BACKGROUND

Recently, we demonstrated increased oxidative stress in the interstitium of ureteral obstructed kidneys based on the increased expression of heme oxygenase-1 and immunohistochemical detection of advanced glycation end products (AGE) in the interstitium. Antioxidant therapy may have a therapeutic potential toward interstitial fibrosis of unilateral ureteral obstruction (UUO) kidneys. Fluvastatin is an HMG-CoA reductase inhibitor and has been demonstrated to have an antioxidant activity in vitro.

METHODS

The effects of fluvastatin on UUO kidneys from the viewpoints of antioxidant action in vivo and antifibrosis action were studied. To investigate the antioxidant action and its therapeutic efficacy of fluvastatin in UUO kidneys, AGE accumulation and fibrosis in the obstructed kidneys was compared among vehicle-, pravastatin-, or fluvastatin-treated (10 or 40 mg/kg/day) groups.

RESULTS

Tubulointerstitial fibrosis was significantly attenuated in fluvastatin-treated animals. Fluvastatin significantly suppressed the degree of immunostaining of AGE in UUO kidneys.

CONCLUSIONS

These results provide evidence for the antioxidant action of fluvastatin in vivo. The decreased interstitial fibrosis along with a decreased oxidative stress marker in the interstitial lesion strongly suggests the existence of a causal relationship between them. Fluvastatin may have therapeutic value in slowing or preventing interstitial fibrosis in progressive renal disease.

Circadian rhythm and postural change in natriuresis in non-dipper type of essential hypertension

Recently we found that, in non-dipper type of essential hypertensive patients who showed the lack of nocturnal fall in blood pressure, circadian rhythm of urinary sodium excretion rate was disturbed. In the present study we examined whether postural change in natriuresis is also disturbed in non-dippers. Sixteen inpatients with essential hypertension were maintained on a relatively high sodium diet containing 10 to 12 g of NaCl per day for 8 days. On the 7th day of the study period, 24-h ambulatory blood pressures were measured, and 5-7th days urinary samples were collected for both daytime and night-time. On the last day of the study period, patients stood for 2 h and then lay down for 2 h. Urinary volume and excretion rates of creatinine and sodium were measured every hour in both positions. Night-time urinary sodium excretion rate was significantly higher in non-dippers (n = 9) than that in dippers (n = 7). Night/day ratio of mean arterial pressure had a positive relationship with night/day ratio of urinary sodium excretion rate. In non-dippers, but not in dippers, the mean value of U(Na)V during upright position was significantly lower than that during supine position. There was a significantly negative relationship between upright/supine ratio of U(Na)V and night/day ratio of MAP or night/day ratio of U(Na)V. In patients with non-dipper type of essential hypertension, both natriuresis patterns, circadian rhythm and postural change, were disturbed.

Prevalence of renal artery stenosis in autopsy patients with stroke

BACKGROUND AND PURPOSE

Atherosclerotic renal artery stenosis commonly exists as one manifestation of more generalized atherosclerosis. It is a progressive but potentially curable disorder. Thus, information on renal artery involvement in atherosclerotic diseases could be important. We investigated the prevalence of renal artery stenosis in autopsied patients with stroke over 40 years of age.

METHODS

From 2167 consecutive autopsy patients who died between 1980 and 1997, we studied 346 cases of mean age of 69+/-11 years with clinical evidence of stroke.

RESULTS

Atherosclerotic renal artery stenosis (>/=75% luminal area narrowing) was found in 36 patients (10.4%). Patients with renal artery stenosis were older and had worse renal function. Renal artery stenosis was found in 14.7%, 28.6%, and 23.9% of patients with hypertension, renal insufficiency, and aortic aneurysm, respectively. Extracranial carotid artery stenosis (>50% luminal area narrowing) was found in 101 patients (29.2%). Of the 346 stroke patients, 256 had a history of brain infarction. In patients with brain infarction, renal artery stenosis was found in 31 (12.1%) and carotid stenosis was found in 81 (33.6%). Patients with carotid artery stenosis were more likely to have renal artery stenosis than patients without carotid artery stenosis (24.4% versus 5.9%, P<0.0001). Multiple logistic regression analysis identified renal insufficiency, hypertension, female gender, and presence of carotid artery stenosis as independent predictors of renal artery stenosis in patients with brain infarction.

CONCLUSIONS

These data reveal that atherosclerotic renal artery stenosis is common in patients with stroke, especially in those with brain infarction.

Circadian rhythm of natriuresis is disturbed in nondipper type of essential hypertension

We examined the circadian rhythm of urinary sodium excretion and the effects of sodium restriction on rhythm in both dipper and nondipper types of essential hypertension. Patients (n = 26) with essential hypertension were maintained on relatively high- (10 to 12 g/d of sodium chloride) and low-sodium (1 to 3 g/d) diets for 1 week each. On the last day of each diet, 24-hour blood pressures (BPs) were measured every 30 minutes noninvasively with an automatic device, and on the last 3 days, urinary samples were collected for both daytime (7:00 AM to 9:30 PM) and nighttime (9:30 PM to 7:00 AM). Eight patients were classified as dippers based on a more than 10% reduction in mean arterial pressure (MAP) from daytime to nighttime on a high-sodium diet, and 18 patients were classified as nondippers. A nocturnal decrease in urinary sodium excretion rate (U(Na)V) on the high-sodium diet was observed in dippers (from 7.5 +/- 2.1 during the day to 5.3 +/- 2.5 mmol/h at night; P < 0.0001), but not in nondippers (6.7 +/- 2.1 v 7.6 +/- 2.3 mmol/h; not significant). In nondippers, the night-day ratio of sodium excretion was significantly reduced from 1.2 +/- 0.4 to 0.8 +/- 0.3 (P < 0.003) by sodium restriction; at the same time, the night-day ratio of MAP was reduced from 0.98 +/- 0.04 to 0.93 +/- 0.05 (P < 0.05). In dippers, the night-day ratios of MAP and U(Na)V were not affected by sodium restriction, and both ratios remained constant at less than 1. Before sodium restriction, the night-day ratio of sodium excretion correlated with that of MAP (r = 0.78; P < 0.0001), whereas there was no significant correlation (r = -0.05) after sodium restriction. These findings showed that the circadian rhythm of renal sodium excretion differed between the two types of essential hypertension. The enhanced nocturnal natriuresis and diminished nocturnal BP fall on a high-sodium diet, recognized in nondippers, were both normalized by sodium restriction, resulting in circadian rhythms with nocturnal dips in U(Na)V and BP.

Changes in the circadian rhythm of blood pressure in primary aldosteronism in response to dietary sodium restriction and adrenalectomy

OBJECTIVE

Recently, we found that sodium restriction restored the circadian rhythm of blood pressure from non-dippers to dippers in patients with a sodium-sensitive type of essential hypertension. In the present study, we investigated the effects of sodium restriction on the circadian blood pressure rhythm in patients with primary aldosteronism, a typical sodium-sensitive form of secondary hypertension.

DESIGN AND METHODS

We performed 24 h blood pressure monitoring in eight patients with primary aldosteronism due to unilateral adenoma (Conn's syndrome) during normal-sodium (7-12 g/day of NaCl) and low-sodium (1-3 g/day) diets, and after adrenalectomy.

RESULTS

Sodium restriction lowered the 24 h mean arterial pressure from 116+/-14 to 109+/-12 mmHg (P< 0.01). During a normal-sodium diet, there was no change in systolic, diastolic and mean arterial pressures during the night-time compared with the daytime. In contrast, during a low-sodium diet, all night-time pressure values were significantly lower than those in the daytime. After adrenalectomy, the night-time pressures in patients on a normal-sodium diet were lower than those of the daytime. The nocturnal mean arterial pressure fall was increased by sodium restriction and adrenalectomy.

CONCLUSIONS

These results indicate that the circadian rhythm of blood pressure was disturbed in patients with primary aldosteronism who maintained a relatively high sodium intake. Both adrenalectomy and sodium restriction restored a nocturnal dip in blood pressure in primary aldosteronism. Therefore, sodium restriction affects the circadian blood pressure rhythm in sodium-sensitive types of hypertension, not only in primary hypertension, but also in secondary hypertension.