A case of malignant hypertension as a presentation of atypical hemolytic uremic syndrome.

INTRODUCTION: Malignant hypertension (mHTN) damages multiple target organs, including the kidneys. mHTN has been regarded as one of the causes of secondary thrombotic microangiopathy (TMA); however, a high prevalence of complement gene abnormalities was recently reported in cohorts of mHTN. CASE REPORT: We herein describe a 47-year-old male who presented with severe hypertension, renal failure (serum creatinine (sCr): 11.6 mg/dL), heart failure, retinal hemorrhage, hemolytic anemia, and thrombocytopenia. Renal biopsy findings were consistent with acute hypertensive nephrosclerosis. The patient was diagnosed with secondary TMA associated with mHTN. However, his previous medical history of TMA of unknown origin and family history of atypical hemolytic uremic syndrome (aHUS) suggested as aHUS presenting mHTN, and genetic testing revealed a pathogenic C3 mutation (p.I1157T). The patient required plasma exchange and hemodialysis for 2 weeks and was able to withdraw from dialysis by antihypertensive therapy without eculizumab. Renal function gradually improved to a sCr level of 2.7 mg/dL under antihypertensive therapy for 2 years after the event. There was no recurrence, and renal function was preserved throughout a 3-year follow-up. DISCUSSION: mHTN is a common presentation of aHUS. In cases of mHTN, abnormalities in complement-related genes may be involved in the development of the disease.

Antibiotic prophylaxis for percutaneous renal biopsy: study protocol for a prospective randomized trial.

BACKGROUND: The major complication of renal biopsy is bleeding. Infection is an extremely rare complication of percutaneous renal biopsy, providing sterile techniques are used and bowel perforation does not occur. However, the questionnaire included in the Kidney Biopsy Guidebook 2020 in Japan reported that antibiotic prophylaxis was administered to patients undergoing percutaneous renal biopsy at 61% of 170 adult institutions and 57% of 54 pediatric institutions. The objective of this study is to show the non-inferiority of not administering antibiotic prophylaxis for percutaneous renal biopsy. METHODS: Patients aged ≥15 years who are scheduled to undergo percutaneous renal biopsy are eligible for inclusion in the study. Three hundred and sixty-four patients will be recruited at 6 hospitals. The patients will be randomly assigned at a 1:1 ratio to receive either a single dose of intravenous cefazolin (1 g) or no antibiotic prophylaxis. The primary outcome is the number of patients that exhibit positive urine cultures (>105 colony-forming units/ml) 3 or 4 days after the renal biopsy, or at which point the patients are diagnosed with pyelonephritis until 3 or 4 days after the renal biopsy. The secondary outcomes are the number of patients who are diagnosed with pyelonephritis within 30 days after the renal biopsy, the number of patients who are diagnosed with puncture site infections within 30 days after the renal biopsy, the number of patients who are diagnosed with an infection other than pyelonephritis or a puncture site infection within 30 days after the renal biopsy, and the number of patients who experience cefazolin-induced side effects. DISCUSSION: This randomized controlled trial aims to show the non-inferiority of not administering antibiotic prophylaxis for percutaneous renal biopsy. If this study shows that antibiotic prophylaxis is not needed, it would help to ensure patient safety and prevent the development of antibiotic-resistant bacteria. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR) UMIN000042378 . Registered on 7 Nov 2020.

Nivolumab-associated glomerular endothelial injury in a patient with gastric cancer.

A 68-year-old male with gastric cancer was treated with tegafur/gimeracil/oteracil and oxaliplatin for 6 months. Thereafter, he was treated with paclitaxel and ramucirumab for 3 months. However, neither regimen had much effect. Thus, he was treated with nivolumab for 2 months, but he developed proteinuria, microhematuria, and an acute kidney injury. A kidney biopsy revealed occasional swollen endothelial cells and proliferating mesangial cells. Few abnormal findings were seen in the tubules or interstitial tissue. Immunofluorescent staining showed segmental immunoglobulin A and complement component 3 deposition, in the mesangial area. Electron microscopy showed a small amount of electron-dense deposits in the paramesangial area and swollen endothelial cells. Mesangial interposition, the loss of endothelial cell fenestration, and subendothelial edema were also observed. Furthermore, foot process effacement and villous transformation of epithelial cells were noted. After the discontinuation of nivolumab, the patient's renal function gradually improved, and his proteinuria disappeared. Nivolumab treatment was restarted at that time because of cancer progression; however, it was ineffective. No occult blood was detected from 7 months after the administration of the last dose of nivolumab. This is a unique case, in which a kidney biopsy revealed evidence of nivolumab-associated glomerular endothelial injury.

Evaluation of the performance, operability, and safety of Plasauto µ, a new type of machine for cell-free and concentrated ascites reinfusion therapy, in a postmarketing clinical study.

Cell-free and concentrated ascites reinfusion therapy (CART) is performed by collecting the ascites from the patient, followed by filtration and concentration. Thereafter, concentrated cell-free ascites is reinfused into the patient intravenously. The new type of machine, Plasauto µ, for managing the process of CART was launched onto the market. We have evaluated the machine through postmarketing clinical study in 17 patients with malignant ascites. The amounts of original and concentrated ascites were 3673 ± 1920 g and 439 ± 228 g, respectively. Recovery rates were acceptable regarding values of total protein, albumin, and IgG that were 55.6% ± 17.3%, 60.2% ± 20.8%, and 58.2% ± 20.5%, respectively. Recovery rates were positively associated with amounts of original ascites and negatively associated with total protein concentration. No adverse events related to the machine were observed. The new type of machine showed preferable performance in processing malignant ascites.

Idiopathic immune complex-mediated tubulointerstitial nephritis with hypocomplementemia and neutrophil-rich interstitial infiltrates
.

A 69-year-old man presented with acute kidney injury, hypocomplementemia, antinuclear antibody, and anti-dsDNA antibody. He had no signs of systemic lupus erythematosus or Sjögren syndrome. He had not begun taking any new drugs in the preceding 6 months. Kidney biopsy revealed 13 glomeruli, 3 with global sclerosis. The remaining glomeruli showed slight mesangial proliferation. The interstitial inflammation was extensive, comprising mainly mature lymphocytes and plasma cells, neutrophils, and a few eosinophils. Remarkable granular and diffuse deposition of IgG and C1q was observed along the tubular basement membranes. Electron microscopy showed electron-dense deposits in the tubular basement membrane. Immunohistochemistry showed only 1 - 4 IgG4-positive plasma cells per high-power field and an IgG4/CD138 ratio of ~ 10%. He was treated with oral prednisolone 35 mg/day, and his kidney function gradually improved. This is a unique case that is not consistent with any known disease entities with immune complex-mediated tubulointerstitial nephritis.
.

Chemotherapy in cancer patients undergoing haemodialysis: a nationwide study in Japan.

BACKGROUND: Cancer is a major cause of death in patients undergoing haemodialysis. However, information about the actual clinical practice of chemotherapy for patients with cancer undergoing haemodialysis is lacking. We conducted a nationwide survey using questionnaires on the clinical practice of chemotherapy for such patients. PATIENTS AND METHODS: The nationwide survey included patients undergoing haemodialysis who were subsequently diagnosed with cancer in 20 hospitals in Japan from January 2010 to December 2012. We reviewed their clinical data, including cancer at the following primary sites: kidney, colorectum, stomach, lung, liver, bladder, pancreas and breast. The questionnaires consisted of the following subjects: (1) patient characteristics; (2) regimen, dosage and timing of chemotherapy; and (3) clinical outcome. RESULTS: Overall, 675 patients were registered and assessed for main primary cancer site involvement. Of 507 patients with primary site involvement, 74 patients (15%) received chemotherapy (44 as palliative chemotherapy and 30 as perioperative chemotherapy). The most commonly used cytotoxic drugs were fluoropyrimidine (15 patients), platinum (8 patients) and taxane (8 patients), and the dosage and timing of these drugs differed between institutions; however, the dosage of molecular targeted drugs (24 patients) and hormone therapy drugs (15 patients) was consistent. The median survival time of patients receiving palliative chemotherapy was 13.0 months (0.1-60.3 months). Three patients (6.8%) died from treatment-related causes and nine patients (20%) died of causes other than cancer. Of the 30 patients who received perioperative chemotherapy, 6 (20%) died of causes other than cancer within 3 years after the initiation of chemotherapy. CONCLUSION: Among the haemodialysis patients with cancer who received chemotherapy, the rates of mortality from causes other than cancer might be high for both palliative and perioperative chemotherapy. Indications for the use of chemotherapy in patients undergoing haemodialysis should be considered carefully.

Membranoproliferative glomerulonephritis with unusual deposits of parallel arrangement striated structure: a new pathological entity?
.

A 71-year-old male with a past history of lower limb arteriosclerosis obliterans developed nephrotic syndrome and renal dysfunction. Renal biopsy showed diffuse global endocapillary proliferative lesions with infiltration of mononuclear cells and occasional foam cells. An irregular double contour of the glomerular basement membrane and global mild-to-moderate mesangial proliferative lesions were observed, indicating membranoproliferative glomerulonephritis. Congo red staining was negative. Routine immunofluorescence studies showed no obvious immunoglobulin or complement depositions. Electron microscopy showed endocapillary proliferative lesions and infiltration of macrophages with abundant lysosomes. Irregular subepithelial, subendothelial, and mesangial electron-dense deposits were observed in glomeruli. In these electron-dense deposits, parallel arrangement striated structures were detected. All known disease entities with Congo red-negative and immunoglobulin-negative glomerular deposits were pathologically excluded. The glomerular lesion in our case might be a new disease entity.
.

Thrombotic microangiopathy associated with cetuximab, an epidermal growth factor receptor inhibitor
.

Cetuximab is a chimeric human-murine monoclonal antibody that binds competitively and with high affinity to the epidermal growth factor receptor (EGFR) and is used to treat advanced squamous cell carcinoma of the head and neck. After receiving a total of six doses of cetuximab, a 72-year-old male presented with pretibial edema, acne-like skin rash, and nephrotic syndrome. The renal biopsy findings revealed features of thrombotic microangiopathy (TMA), with the expansion of the subendothelial zone, reduplication of the glomerular basement, and swelling of the endothelial cells. Nine weeks after the discontinuation of cetuximab, his pretibial edema had disappeared and proteinuria decreased. To our knowledge, this is the first report in which kidney biopsy revealed evidence of TMA due to cetuximab administration. Our report suggests that it may be prudent to monitor patients receiving cetuximab closely for the possible development of nephrotic syndrome.
.

Post-infectious acute glomerulonephritis with vasculitis and pulmonary hemorrhage.

An 84-year-old male complained of fever, cough, sputum, and appetite loss. His renal function rapidly worsened, and he had hypoalbuminemia and hypocomplementemia. His condition worsened and C-reactive protein levels were elevated. Vasculitis syndrome was suspected and he was administered 40 mg of prednisolone, although myeloperoxidase antineutrophil cytoplasmic antibody (ANCA), proteinase-3 ANCA and antiglomerular basement membrane antibody tests were negative. His body temperature decreased and fatigue promptly resumed. On renal biopsy, light microscopy revealed endocapillary and extracapillary glomerulonephritis. Vasculitis was detected in interlobular arteries. Immunofluorescence studies revealed granular deposits of C3 and IgG along capillary walls. Electron microscopy revealed dome-shaped small electron-dense granular subepithelial deposits. Acute post-infectious glomerulonephritis was suspected. Although his renal function improved, he developed hemoptysis and was diagnosed with pulmonary hemorrhage. He received methylprednisolone and plasma exchange, and his respiratory status improved gradually. This is an extremely rare case and suggests the importance of considering a differential diagnosis.

Chaga mushroom-induced oxalate nephropathy.

Chaga mushrooms have been used in folk and botanical medicine as a remedy for cancer, gastritis, ulcers, and tuberculosis of the bones. A 72-year-old Japanese female had been diagnosed with liver cancer 1 year prior to presenting at our department. She underwent hepatectomy of the left lobe 3 months later. Chaga mushroom powder (4 - 5 teaspoons per day) had been ingested for the past 6 months for liver cancer. Renal function decreased and hemodialysis was initiated. Renal biopsy specimens showed diffuse tubular atrophy and interstitial fibrosis. Oxalate crystals were detected in the tubular lumina and urinary sediment and oxalate nephropathy was diagnosed. Chaga mushrooms contain extremely high oxalate concentrations. This is the first report of a case of oxalate nephropathy associated with ingestion of Chaga mushrooms.

Gamma 1-heavy chain deposition disease accompanied by IgG kappa in serum, urine, and bone marrow.

A 32-year-old Japanese woman presented with hypertension, nephrotic syndrome, microhematuria, and severe hypocomplementemia. Her serum creatinine concentration increased from 1.46 mg/dL (129.0 µmol/L) to 3.46 mg/dL (305.8 µmol/L) over 1 month. Renal biopsy revealed Congo red-negative nodular glomerulosclerosis accompanied by mesangial proliferation. There was extensive staining of immunoglobulin (Ig) G in the glomerular and tubular basement membranes and expanded mesangial regions. Staining was negative for IgA, IgM, and kappa and lambda light chains and positive for the gamma 1 IgG subclass. Staining for constant domains of the gamma heavy chains showed a deletion of the first constant domain (CH1). Electron microscopy revealed electron-dense deposits in the glomerular and tubular basement membranes and mesangium. These findings indicated gamma 1-heavy chain deposition disease (HCDD). Serum and urine immunoelectrophoresis revealed an IgG kappa monoclonal band, whereas bone marrow biopsy revealed monoclonal plasmacytosis with positive staining for kappa chains. HCDD associated with kappa light chain is extremely rare. We report the first case of HCDD with IgG kappa detected in the serum, urine, and bone marrow.

Glomerular endotheliosis in a pregnant woman with severe gestational proteinuria.

Preeclampsia is the most common hypertensive disorder to occur during pregnancy. A healthy 38-year-old primipara presented with pretibial edema at 33 weeks of gestation followed by the development of proteinuria at 36 weeks of gestation. She had no past medical history of hypertension and was normotensive during gestation. Her proteinuria persisted after delivery, and she was also hypoalbuminemic. A renal biopsy revealed a remodeling of the glomerular basement membrane (GBM) with double contours. Some of the glomerular segments showed endothelial swelling. Immunoperoxidase staining for C4b-binding protein was positive and Protein S was weakly detected in the GBM. Electron microscopy revealed an expansion of the subendothelial zone as well as mesangial cell interposition. This case suggests that glomerular endotheliosis may therefore sometimes be present despite the absence of hypertension.

Predicting the outcome of chronic kidney disease by the estimated nephron number: the rationale and design of PRONEP, a prospective, multicenter, observational cohort study.

BACKGROUND: The nephron number is thought to be associated with the outcome of chronic kidney disease (CKD). If the nephron number can be estimated in the clinical setting, it could become a strong tool to predict renal outcome. This study was designed to estimate the nephron number in CKD patients and to establish a method to predict the outcome by using the estimated nephron number. METHODS/DESIGN: The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient. This will be a multicenter, prospective (minimum 3 and maximum 5 years follow-up) study. The subjects will comprise CKD patients aged over 14 years who have undergone a kidney biopsy. From January 2011 to March 2013, we will recruit 600 CKD patients from 10 hospitals belonging to the National Hospital Organization of Japan. The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR. The secondary parameter is the rate of eGFR decline per year. The nephron number will be estimated by the glomerular density in biopsy specimens and the renal cortex volume. This study includes one sub-cohort study to establish the equation to calculate the renal cortex volume. Enrollment will be performed at the time of the kidney biopsy, and the data will consist of a medical interview, ultrasound for measurement of the kidney size, blood or urine test, and the pathological findings of the kidney biopsy. Patients will continue to have medical consultations and receive examinations and/or treatment as usual. The data from the patients will be collected once a year after the kidney biopsy until March 2016. All data using this study are easily obtained in routine clinical practice. DISCUSSION: This study includes the first trials to estimate the renal cortex volume and nephron number in the general clinical setting. Furthermore, this is the first prospective study to examine whether the nephron number predicts the outcome of CKD patients. The results from this study should provide powerful new tools for nephrologists in routine clinical practice. TRIAL REGISTRATION: UMIN-Clinical Trial Registration, UMIN000004784.

A rare case of malignant-phase hypertension with pulmonary alveolar hemorrhage.

Malignant-phase hypertension is characterized clinically by severe accelerating hypertension with neuroretinopathy or papilledema and by evidence of renal damage. A Japanese male in his early thirties presented with hemoptysis and general fatigue. He had a 5-year history of hypertension, but had not received any treatment. His blood pressure was 290/150 mmHg and his serum creatinine level was 8.24 mg/dL. Chest X-rays and computed tomography scans of the chest revealed a pulmonary alveolar hemorrhage. He was suspected of having vasculitis syndrome or Goodpasture's syndrome, but his renal biopsy specimen showed malignant nephrosclerosis. Myeloperoxidase antineutrophil cytoplasmic antibody (ANCA), proteinase-3 ANCA and antiglomerular basement membrane antibody were negative. He was treated with a calcium antagonist and a ß-blocker, followed by an angiotensin-converting enzyme inhibitor. After the administration of the ß-blocker, his blood pressure decreased and his renal function gradually improved. This is a rare case of malignant-phase hypertension with pulmonary alveolar hemorrhage; this condition should be considered in the differential diagnosis in order to avoid unnecessary treatment such as immunosuppressive therapy.

Fatal hemoperitoneum due to rupture of the left gastric artery in a patient with microscopic polyangiitis.

Microscopic polyangiitis is a vasculitis which primarily affects capillaries, venules or arterioles. Involvement of small and medium-sized arteries may also occur. A 70-year-old Japanese female with a fever and cough was diagnosed with pneumonia and antibiotics were administered. Her symptoms initially improved, but her fever recurred and she experienced malaise and loss of appetite. Her renal function gradually worsened and she was positive for myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA). She was referred to our hospital on the suspicion of ANCA-associated glomerulonephritis. However, her depressive mental symptoms did not allow her to undergo a renal biopsy. She was clinically diagnosed with ANCA-associated glomerulonephritis, and oral corticosteroids and intravenous methylprednisolone were administered. Her symptoms and renal function were improved, but she died suddenly 15 days after admission. An autopsy disclosed approximately 700 mL bloody ascites. Coagulation adhered to the lesser curvature of the stomach, but the source of hemorrhage could not be detected macroscopically because the gastric mucosa did not show abnormal findings. The histological findings revealed that the left gastric artery showed necrotizing angiitis and rupture. In the kidneys, cellular crescents were found in approximately 10%, fibrous crescents were found in approximately 10%, sclerosis and collapse were found approximately 30% of the glomeruli, and necrotizing angiitis was observed in interlobular arteries and arterioles. From these findings, she was finally diagnosed with microscopic polyangiitis. Microscopic polyangiitis is an extremely rare cause of spontaneous intraperitoneal bleeding, but it must be carefully considered in the differential diagnosis for the appropriate management of such patients.

[Myasthenia-like syndrome induced by cibenzoline overdose in a patient with chronic kidney disease].

A female in her late 60s with chronic kidney disease was admitted to the emergency department with complaints of dizziness four days prior to hospitalization. Cibenzoline (300 mg/day) was administered for atrial fibrillation, which was detected in an electrocardiogram. After three days, she experienced blepharoptosis and was admitted for suspected myasthenia gravis. However, the anti-acetylcholine receptor antibody and edrophonium tests were negative. On day four after hospitalization, she suffered from pneumonia with pleural effusion and she was put on a respirator for four days. From day 16 after hospitalization, she had diarrhea and her renal function worsened. At the same time, a gradual aggravation of right blepharoptosis, dull headache, weakness and difficulty in chewing were noted. She experienced dyspnea on day 31 after hospitalization. Chest X-ray film did not show a pneumonia shadow or pleural effusion, and arterial blood gases revealed hypercapnia; she was diagnosed as having CO2 narcosis due to respiratory muscle fatigue and was put on a respirator again. Myasthenia-like syndrome was suspected because of a probable overdose of cibenzoline and administration of cibenzoline was withdrawn. Her condition improved and she was taken off the respirator on day 35 after hospitalization. Repetitive stimulation of 5 Hz was applied to her right facial nerve along with evoked electromyogram(EMG) on days 2 and 11 after discontinuing cibenzoline. On day 2, the EMG showed a waning phenomenon, whereas no such phenomenon was seen on day 11. The blood concentration of cibenzoline immediately after withdrawal was extremely high (2448 ng/mL). When this drug is administered to a patient with chronic kidney disease, attention must be paid to the indication, dose, and manifestation of the possible side effects.

Role of prostaglandin E receptor EP1 subtype in the development of renal injury in genetically hypertensive rats.

One of the major causes of end-stage renal diseases is hypertensive renal disease, in which enhanced renal prostaglandin (PG) E2 production has been shown. PGE2, a major arachidonic acid metabolite produced in the kidney, acts on 4 receptor subtypes, EP1 through EP4, but the pathophysiological importance of the PGE2/EP subtypes in the development of hypertensive renal injury remains to be elucidated. In this study, we investigated whether an orally active EP1-selective antagonist (EP1A) prevents the progression of renal damage in stroke-prone spontaneously hypertensive rats (SHRSP), a model of human malignant hypertension. Ten-week-old SHRSP, with established hypertension but with minimal renal damage, were given EP1A or vehicle for 5 weeks. After the treatment period, vehicle-treated SHRSP showed prominent proliferative lesions in arterioles, characterized by decreased alpha-smooth muscle actin expression in multilayered vascular smooth muscle cells. Upregulation of transforming growth factor-beta expression and tubulointerstitial fibrosis were also observed in vehicle-treated SHRSP. All these changes were dramatically attenuated in EP1A-treated SHRSP. Moreover, EP1A treatment significantly inhibited both increase in urinary protein excretion and decrease in creatinine clearance but had little effect on systemic blood pressure. These findings indicate that the PGE2/EP1 signaling pathway plays a crucial role in the development of renal injury in SHRSP. This study opens a novel therapeutic potential of selective blockade of EP1 for the treatment of hypertensive renal disease.

Roles of connective tissue growth factor and prostanoids in early streptozotocin-induced diabetic rat kidney: the effect of aspirin treatment.

BACKGROUND: Connective tissue growth factor (CTGF) is a cysteine-rich growth factor induced by transforming growth factor-beta (TGF-beta) and is thought to play a critical role in TGF-beta-stimulated extracellular matrix accumulation. To explore its involvement in early diabetic nephropathy, we investigated the time course of CTGF gene expression and its regulation in streptozotocin (STZ)-induced diabetic rat kidney. METHODS: Northern blot analysis for CTGF, TGF-beta, and fibronectin expression was performed in the glomeruli of STZ-induced diabetic rats from 3 days to 12 weeks after the induction of diabetes, together with histological examination. To investigate the role of prostanoids in this process, aspirin was administered in one group of diabetic rats. Furthermore, CTGF expression was analyzed in rat mesangial cells cultured under high-glucose conditions. RESULTS: Glomerular expression of CTGF and TGF-beta1 mRNA was coordinately upregulated as early as day 3, followed by fibronectin induction and mesangial matrix accumulation. Chronic aspirin treatment in diabetic rats significantly attenuated mesangial expansion, and effectively suppressed CTGF induction, as well as inhibiting the upregulation of TGF-beta1 and fibronectin expression. In cultured mesangial cells, aspirin treatment abolished high glucose-stimulated CTGF upregulation. CONCLUSIONS: These results indicate that CTGF expressed in the glomeruli is upregulated in the early stage of STZ-induced diabetic nephropathy in rats, and could be a critical mediator of the development of diabetic glomerulosclerosis. In addition, the modulatory effects of aspirin during this process suggest a role of the cyclooxygenase pathway in the progression of diabetic nephropathy.

Angiogenic protein Cyr61 is expressed by podocytes in anti-Thy-1 glomerulonephritis.

Dynamic recovery of glomerular structure occurs after severe glomerular damage in anti-Thy-1 glomerulonephritis (Thy-1 GN), but its mechanism remains to be investigated. To identify candidate genes possibly involved in glomerular reconstruction, screening was performed for genes that are specifically expressed by podocytes and are upregulated in glomeruli of Thy-1 GN. Among them, cysteine-rich protein 61 (Cyr61 or CCN1), a soluble angiogenic protein belonging to the CCN family, was identified. By Northern blot analysis, Cyr61 mRNA was markedly upregulated in glomeruli of Thy-1 GN from day 3 through day 7, when mesangial cell migration was most prominent. By in situ hybridization and immunohistochemistry, Cyr61 mRNA and protein were expressed by proximal straight tubules and afferent and efferent arterioles in normal rat kidneys and were intensely upregulated at podocytes in Thy-1 GN. Platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-beta1 (TGF-beta1), of which the gene expression in the glomeruli of Thy-1 GN was upregulated in similar time course as Cyr61, induced Cyr61 mRNA expression in cultured podocytes. Furthermore, supernatant of Cyr61-overexpressing cells inhibited PDGF-induced mesangial cell migration. In conclusion, it is shown that Cyr61 is strongly upregulated at podocytes in Thy-1 GN possibly by PDGF and TGF-beta. Cyr61 may be involved in glomerular remodeling as a factor secreted from podocytes to inhibit mesangial cell migration.

Plasma ghrelin and desacyl ghrelin concentrations in renal failure.

Ghrelin is a novel hormone that possesses growth hormone (GH)-releasing, cardiovascular, and metabolic activities. Ghrelin is a unique acylated polypeptide, and the naked peptide, desacyl ghrelin, does not have the activity. This study examines plasma ghrelin concentrations in 41 patients with mild to severe renal diseases. Two kinds of radioimmunoassays were used: amino-terminal immunoreactivity represents ghrelin alone (N-IR), and carboxyl-terminal immunoreactivity corresponds to the sum of both ghrelin and desacyl ghrelin (C-IR). In all subjects, the plasma N-IR was much smaller than the C-IR, indicating that desacyl ghrelin predominates over ghrelin in the circulation. The plasma C-IR, but not N-IR, was significantly correlated with the serum creatinine level and was increased 2.8-fold in patients with end-stage renal disease compared with those in patients with normal renal function. The plasma GH concentration was significantly correlated with the plasma N-IR and the C-IR, as well as with the serum creatinine level. Bilateral nephrectomy in mice caused marked increase in the plasma C-IR without significant changes in the local C-IR and ghrelin mRNA level in the stomach, which is the main site of ghrelin production. These findings suggest that circulating ghrelin concentrations play a role in the regulation of blood GH concentrations and that the kidney is an important site for clearance and/or degradation of desacyl ghrelin. Furthermore, elevation of blood GH levels in renal failure seems to be caused by a mechanism other than alteration in the circulating ghrelin concentration.