Mechanisms of Epithelial-Mesenchymal Transition of Peritoneal Mesothelial Cells During Peritoneal Dialysis

A growing body of evidence indicates that epithelial-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMC) may play an important role in the development and progression of peritoneal fibrosis during long-term peritoneal dialysis (PD) leading to failure of peritoneal membrane function. Here, we review our own observations and those of others on the mechanisms of EMT of HPMC and suggest potential therapeutic strategies to prevent EMT and peritoneal fibrosis during long-term PD. We found that high glucose and H2O2 as well as transforming growth factor-beta1 (TGF-beta1) induced EMT in HPMC and that high glucoseinduced EMT was blocked not only by inhibition of TGF-beta1 but also by antioxidants or inhibitors of mitogen-activated protein kinases (MAPK). Since MAPKs are downstream target molecules of reactive oxygen species (ROS), these data suggest that high glucose-induced generation of ROS and subsequent MAPK activation mediate high glucose-induced EMT in HPMC. We and others also observed that bone morphogenetic protein-7 (BMP-7) prevented EMT in HPMC. Glucose degradation products (GDP) were shown to play a role in inducing EMT. Involvement of a mammalian target of rapamycin (mTOR) in TGF-beta1-induced EMT has also been proposed in cultured HPMC. A better understanding of the precise mechanisms involved in EMT of HPMC may provide new therapeutic strategies for inhibiting peritoneal fibrosis in long-term PD patients.

Antifibrotic Effect of BMP-7 in the Peritoneum and the Mechanism / 대한신장학회잡지

PURPOSE: Bone morphogenic protein (BMP)-7, a member of TGF-beta1 superfamily, is an endogenous antifibrotic protein highly expressed in normal kidney. It is not known, however, whether human peritoneal mesothelial cells (HPMC) express BMP-7 or if BMP-7 protects against peritoneal fibrosis and by what mechanism. We examined the effect of BMP-7 overexpression in TGF-beta1-induced epithelial-mesenchymal transition (EMT) of HPMC and in TGF-beta1 signaling in HPMC to elucidate the mechanisms of antifibrotic effect of BMP-7. METHODS: Growth arrested and synchronized HPMC were stimulated with 2 ng/mL of TGF-beta1 to induce EMT. HPMC were transiently transfected with adenovirus-mediated human BMP-7 (AdBMP-7) or with GFP (AdGFP). EMT was defined as downregulation of E-cadherin and upregulation of alpha-smooth muscle actin (SMA). RESULTS: HPMC constitutively expressed BMP-7 mRNA and protein. BMP-7 mRNA and protein expression were significantly inhibited by 50 mM D-glucose, 2x diluted commercial peritoneal dialysis solution, and 2 ng/ml of TGF-beta1. Transfection of AdBMP-7 resulted in 2.5-fold increase in BMP-7 mRNA expression in HPMC. TGF-beta1 significantly decreased E-cadherin and increased alpha-SMA expression in GFP transfected cells. BMP-7 overexpression effectively reversed TGF-beta1-induced E-cadherin and alpha-SMA expression and significantly suppressed TGF-beta1-induced phosphorylation of Smad2/3, ERK1/2, JNK, and p38 MAPK in HPMC as compared to GFP transfected cells. CONCLUSION: BMP-7 is an endogenous antifibrotic protein and downregulation of BMP-7 in HPMC by high glucose, PD solution, and TGF-beta1 may permit the development of peritoneal fibrosis during long-term PD. Our data demonstrate that BMP-7 overexpression reverses TGF-beta1-induced EMT of HPMC and consequent peritoneal fibrosis possibly through inhibition of Smad2/3 and MAPK phosphorylation.

Osteomyelitis of the Rib Following Internal Jugular Vein Catheter Insertion / 대한신장학회잡지

Internal jugular vein catheter is frequently used for emergency hemodialysis. Various complications have been reported. Infection is one of the problem after long term use. There have been reports of osteomyelitis of clavicle secondary to subclavian catheterization but not osteomyelitis associated with internal jugular vein catheterization. There are two possible pathways of infection. One is hematogenous spread from another focus in the body or sepsis. The other is transmission of focal infection. Manipulation of the needle may perforate the vein and produce hematoma. The infected hematoma may have resulted in abscess formation around the rib and subsequent osteomyelitis. Herein we report a case of osteomyelitis of the rib complicating internal jugular vein catheterization with a review of the literature.

Role of Reactive Oxygen Species in Transforming Growth Factor - beta1 - inuduced Fibronectin Secretion and alpha - Smooth Muscle Actin Expression in Human Lung Fibroblasts / 결핵및호흡기질환

BACKGROUND: The transforming growth factor-beta1 (TGF-beta1) plays a key role in lung fibrosis. However, the mole?cular mechanisms involved in TGF-beta1-induced lung fibrosis are unclear. TGF-beta1 is the key inducer of myofibroblast transdifferentiation via de novo synthesis of alphasmooth muscle actin (alpha-SMA). Since TGF-beta1 signals through reactive oxygen species (ROS) and ROS have been shown to induce accumulation of extracellular matrix (ECM) in various tissues, this study examined if ROS play a role in TGF-beta1-induced fibronectin secretion and alpha-SMA expression in human lung fibroblasts, MRC-5 cells. METHODS: Growth arrested and synchronized MRC-5 cells were stimulated with TGF-beta1 (0.2-10 ng/ml) in the presence or absence of N-acetylcysteine (NAC) or diphenyleneiodonium (DPI) for up to 96 hours. Dichlorofluorescein (DCF)- sensitive cellular ROS were measured by FACScan and secreted fibronectin and cellular alpha-SMA by Western blot analysis. RESULTS: TGF-beta1 increased the level of fibronectin secretion and alpha-SMA expression in MRC-5 cells in a dose- dependent manner. Both NAC (20 and 30 mM) and DPI (1 and 5 microM significantly inhibited TGF-beta1-induced fibronectin and alpha-SMA upregulation. The TGF-beta1-induced cellular ROS level was also significantly reduced by NAC and DPI. CONCLUSIONS: The results suggest that NADPH oxidase-dependent ROS play an important role in TGF-beta1-induced fibronectin secretion and alpha-SMA expression in MRC-5 cells, which leads to myofibroblast transdifferentiation and progressive lung fibrosis.

Increased Intracellular Reactive Oxygen Species in Peripheral Blood Mononuclear Cells from Renal Transplant Recipients with Decreased Graft Function / 대한이식학회지

PURPOSE: Oxidative stress plays an important role in the development and progression of renal injury. However, the role of reactive oxygen species (ROS) in renal allograft dysfunction is not clear. The present study examined the level of intracellular ROS in healthy control (kidney donor, n=37), end-stage renal disease (ESRD) patients (n=36), transplant recipients with serum creatinine (Scr) less than 1.5 mg% (n=33), and recipients with Scr between 1.5 and 5.0 mg% (n=36) at least one year after renal transplantation. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated by Ficoll-Hypaque gradient method. Dichlorofluorescein (DCF)-sensitive ROS was measured by flow cytometry and expressed as an arbitrary unit. RESULTS: Basal ROS production in PBMC was significantly increased in ESRD patients compared to healthy control. Basal ROS production in both transplant patient groups was not significantly different from healthy control. Phorbol-12-myristate-13- acetate (PMA) and hydrogen peroxide significantly enhanced intracellular ROS in all 4 groups. PMA- and hydrogen peroxide-induced cellular ROS was significantly higher in renal recipients with Scr between 1.5 and 5.0 mg% than in both healthy control and patients with Scr below 1.5 mg%. In regression analysis all, PMA- and hydrogen peroxide- induced as well as basal intracellular ROS in PBMC was correlated with Scr. CONCLUSION: Our results demonstrate that oxidative stress correlates with the declining of renal graft function.

Renal Perfusion Image Using Harmonic Ultrasound with Microbble Contrast Agent: Preliminary Study

PURPOSE: To compare, in terms of their feasibility and normal range, 99mTc-DTPA renal perfusion imaging and renal perfusion imaging using harmonic ultrasound (US) with a microbubble contrast agent for the evaluation of renal perfusion after renal transplantation. MATERIALS AND METHODS: During a six-month period, thirty patients who had received a renal transplant underwent both 99mTc-DTPA renal perfusion imaging and renal perfusion imaging using harmonic US with a microbubble contrast agent. Sonographic renal perfusion images were obtained before and after a bolus injection of the microbubble contrast agent LevovistTM (SH U 508A; Schering AG, Berlin, Germany) every 3 seconds for 3 minutes. Sonographic renal perfusion images were converted into a renal perfusion curve by a computer program and Tpeak of the curve thus obtained was compared with that of the 99mTc-DTPA curve. RESULTS: Average Tpeak of the 99mTc-DTPA renal perfusion curve was 16.2 seconds in the normal group and 39.6 seconds in the delayed perfusion group, while average Tpeak of the sonographic renal perfusion curve was 23.7 seconds and 46.2 seconds, respectively. Tpeak of the sonographic renal perfusion curve showed a good correlation with that of the 99mTc-DTPA curve (correlation coefficient=0.8209; p=0.0001). The cut-off value of Tpeak of the sonographic renal perfusion curve was 35 seconds (sensitivity=90%, specificity=95%). CONCLUSION: In patients who have received a renal transplant, the findings of renal perfusion imaging using harmonic US with a microbubble contrast agent show close correlation with those of 99mTc-DTPA renal perfusion imaging. The optimal cut-off value of Tpeak of the sonographic renal perfusion curve was 35 seconds.

Effects of 2,3,7,8-tetrachlorodibenzo- p-dioxin(TCDD) on Glomerular Mesangial and Tubular Epithelial Cell Activation / 대한신장학회잡지

BACKGROUND: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a prototype compound of polyhalogenated aromatic hydrocarbons, produces diverse biologic effects. Although nephrotoxicity of aromatic hydrocarbons such as benzo[a]pyrene(BP) is well known, little is known about the effects of TCDD on renal function. Thus, the present study examined the effects of TCDD on cell viability, proliferation, and extracellular matrix(ECM) synthesis by glomerular mesangial cells, LLC-PK1 cells representing proximal tubular epithelial cells, and MDCK cells representing distal epithelial cells and compared with the effects of BP. METHODS: Quiescent cells were incubated with serum free media containing different concentrations of TCDD(1-100 nM) and BP(3 and 30 micro M) for 24- 96 hours. Cell viability and proliferation were assessed by lactate dehydrogenase(LDH) release and [3H]-thymidine incorporation, respectively. Secreted fibronectin was measured by Western blot analysis. RESULTS: When cells were continuously exposed to TCDD, LDH release significantly increased in MMC, LLC-PK1, and MDCK in a dose- and a time- dependent manner. [3H]-Thymidine incorporation was increased in MMC and LLC-PK1 but decreased in MDCK by TCDD. Contrary to TCDD, 30 micro BP significantly inhibited [3H]-thymidine incorporation in MMC and MDCK but not in LLC-PK1. Both TCDD and BP increased fibronectin secretion by MMC, LLC-PK1, and MDCK cells, suggesting that TCDD and BP may cause renal fibrosis leading to loss of renal function. CONCLUSION: These data provide experimental evidence that TCDD can alter cell viability and proliferation and increase ECM synthesis by renal cells which may lead to renal injury.

N epsilon(Carboxymethyl)Lysine-Induced Mesangial Cell Activation / 대한신장학회잡지

BACKGROUND: Advanced glycation end products (AGE) are independent risk factors in the development and progression of diabetic nephropathy. Receptor for AGE(RAGE) is considered the main receptor involved in AGE-induced cell activation. Galectin-3, another AGE receptor, has recently been found upregulated in mesangial cells(MC) cultured under high glucose and in diabetic rat kidneys. N epsilon(carboxymethyl)lysine(CML) is a well characterized AGE but its role in MC activation is unknown. The present study examined the effects of CML on MC proliferation and extracellular matrix(ECM) secretion. METHODS: Synchronized rat MC were stimulated with different concentrations of CML-bovine serum albumin(BSA), control BSA, and transforming growth factor-beta(TGF-beta) for up to 72 hours. Cell proliferation was measured by [3H]-thymidine incorporation. Fibronectin, TGF-beta, plasminogen activator inhibitor(PAI)-1 secreted into the media and RAGE and galectin-3 expression in MC were measured by Western blot analysis and ELISA. RESULTS: 1,000 micro /mL of CML-BSA decreased [3H]-thymidine incorporation by MC at 48 hours and 10 ng/mL TGF-beta at 24 and 48 hours. CML-BSA 100 and 1,000 micro /mL, control BSA 1,000 micro /mL, and TGF-beta 10 ng/mL increased fibronectin secretion at 48 hours. CML-BSA up to 1,000 micro /mL did not affect TGF-beta or PAI-1 secretion. TGF-beta 10 ng/mL, however, significantly increased PAI-1 secretion. Cultured MC expressed both RAGE and galectin-3. CML-BSA 100 micro /mL upregulated galectin-3 expression. CONCLUSION: CML-BSA decreased MC proliferation and increased fibronectin secretion, suggesting that CML may lead to ECM accumulation and glomerulosclerosis in diabetic animals. MC express RAGE and galectin-3 constitutively and CML-induced galectin-3 upregulation may have a role in AGE-induced MC activation.

Monocyte Chemoattractant Protein-1 Upregulates Fibronectin Secretion by Human Peritoneal Fibroblasts / 대한신장학회잡지

BACKGROUND: High glucose upregulates MCP-1 expression in rat glomerular mesangial cells and in human peritoneal mesothelial cells. However, the role of high glucose-induced MCP-1 on the development and progression of diabetic renal injury and peritoneal injury during peritoneal dialysis(PD) using high glucose PD solutions are not clear. Since MCP-1 was shown to upregulate transforming growth factor-beta1(TGF-beta1) and collagen expression in lung fibroblasts, the present study investigated the effects of MCP-1 on fibronectin secretion by mouse mesangial cells(MMC), human peritoneal mesothelial cells (HPMC), and human peritoneal fibroblasts(HPFB). METHODS: Synchronized cells were stimulated by different concentrations of MCP-1(0.1-100 ng/mL) or TGF-beta1(0.1-10 ng/mL) for 48 hours. Fibronectin protein secreted into the media was analyzed by Western blot analysis. RESULTS: MCP-1 up to 100 ng/mL did not affect fibronectin secretion by MMC. TGF-beta1 10 ng/mL, however, increased fibronectin secretion by MMC 2.8 fold that of control. MCP-1 up to 100 ng/mL did not affect fibronectin secretion by HPMC. But, TGF-beta1 0.1 ng/mL increased fibronectin secretion by HPMC 1.8 fold compared to control. On the other hand, MCP-1 increased fibronectin secretion by HPFB in a dose-dependent manner. MCP-1 at 1-10 ng/mL significantly increased fibronectin when compared to M199 control. 100 ng/mL MCP-1 further increased fibronectin secretion by HPFB compared to 0.1-10 ng/mL MCP-1. CONCLUSION: These results suggest a possible role for MCP-1 in the development and progression of peritoneal fibrosis and support the view that in addition to recruiting inflammatory cells MCP-1 may play a role in tissue fibrosis in other organs.

Effects of Osmolality and Osmotic Agents on Viability and Proliferation of Human Peritoneal Mesothelial Cells / 대한신장학회잡지

High glucose activates protein kinase C, induces reactive oxygen species generation, and upregulates expression of transforming growth factor-beta1(TGF-beta1) and fibronectin by human peritoneal mesothelial cells(HPMC). High glucose also induces premature senescence in mesothelial cells. Mesothelial cells shrink after exposure to hypertonic medium and intracellular uptake of amino acids increase to ensure subsequent volume increase. Based on these observations, new and more biocompatible peritoneal dialysis solutions that are glucose free and/or iso-osmolar have been developed. We investigated the effects of different osmolality and different osmotic agents including glucose, mannitol, and icodextrin on viability and proliferation of HPMC. HPMC were obtained from the omental tissues of consenting patients undergoing Cesarean section or elective abdominal surgery. All experiments were performed using cells in the 2nd or 3rd passage. Near-confluent HPMC grown in culture dishes were incubated with serum-free medium for 48 hours to arrest and synchronize cell growth. Lactate dehydrogenase(LDH) release was measured for cell viability and [3H]-thymidine incorporation for proliferation of cultured HPMC, after exposing HPMC to different concentrations of glucose, mannitol, and icodextrin for up to 96 hours. High glucose and mannitol at concentrations up to 100 mM(375 mOsm) did not increase LDH release up to 96 hours compared to control M199. When HPMC were exposed to 2, 4, 7.5, and 9% of icodextrin for 24-96 hours, LDH release did not increase. Glucose at 30, 50, and 100 mM significantly inhibited [3H]-thymidine incorporation by HPMC at 24 and 48 hours. Mannitol at 30, 50, and 100 mM for 24 hours and at only 100 mM for 48 hours also significantly inhibited cell proliferation. Icodextrin 9% (305 mOsm) inhibited cell proliferation compared with control M-199 at 24 hours. In conclusion, high osmolality per se dose not appear to increase HPMC death. However, high osmolality appears to inhibit HPMC proliferation at early stage. In addition, high glucose appears to inhibit HPMC proliferation independent of osmolality since high glucose continues to inhibit cell proliferation at 48 and 72 hours when mannitol at the same concentration did not. Icodextrin 9% of which osmolality is 305 mOsm inhibits HPMC proliferation at early stage but does not appear to increase HPMC death.

Peritoneal Dialysis: Past, Present and Future / 대한신장학회잡지

No abstract available.

The Effect of Declining Small Solute Clearance on Protein Intake and Nutritional Status in Progressive Renal Failure / 대한신장학회잡지

BACKGROUNDS: Malnutrition is common in patients with chronic renal failure(CRF) and various signs of malnutrition are strong predictors of increased morbidity and mortality. Monitoring of protein intake and nutritional status is therefore important in the clinical management of CRF patients. Few studies have demonstrated direct correlations among renal function, protein intake, and nutritional status in a prospective study although clinical experiences suggest such relationship. The aim of this study was to prospectively evaluate correlations between renal function, protein intake, and nutritional status during progressive renal failure. METHODS: A total of 431 studies on renal function, protein intake, and nutritional status was carried out in 282 patients with normal renal function and varying degrees of renal failure before beginning dialysis. Renal functional indices included weekly Kt/Vurea, total weekly creatinine clearance(Ccr, L/week/1.73m2), creatinine clearance(Ccr, mL/min/1.73m2), urea clearance(Curea, mL/min) and residual renal function(RRF, mL/min). Protein intake was assessed from the protein equivalent of total nitrogen appearance normalized by standard weight(nPNA, g/kg/day) by DOQI formula[nPNA(D)], Bergstr m formula 1[nPNA(B1)] and Bergstr m formula 2[nPNA(B2)]. Nutritional indices were fat free edema free body mass(FFEFBM, kg) by creatinine kinetics, %lean body mass(LBM, %) and serum albumin(g/dL). We evaluated correlations between renal function, protein intake and nutritional status by linear regression analysis. In a separate analysis, 237 studies from 94 patients with follow-up studies were analyzed for correlations among renal function, protein intake, and nutritional status. RESULTS: There was a highly significant correlation among weekly Kt/Vurea, weekly creatinine clearance, and residual renal function, among nPNA(D), nPNA (B1), nPNA(B2), and between FFEFBM and %LBM. Significant correlation was also observed between weekly Kt/Vurea and nPNA, between weekly Kt/ Vurea and FFEFBM, between weekly Kt/Vurea and %LBM, between nPNA and FFEFBM, and between nPNA and %LBM. The results were the same in patients with follow-up studies. CONCLUSION: These results clearly demonstrate that renal urea and creatinine clearance is closely correlated with protein intake and nutritional status in predialysis patients. With declining small solute clearances, protein intake decreased and nutritional status became worse. Starting dialysis before malnutrition becomes apparent may improve patient morbidity and mortality after dialysis.

The Effects of Lactate and pH on Human Peritoneal Mesothelial Cell Biology / 대한신장학회잡지

Preservation of peritoneal membrane function is important in the success of long-term peritoneal dialysis (PD). During PD, human peritoneal mesothelial cells (HPMC) are continuously exposed to unphysiological peritoneal dialysis solution(PDS) charaterized by high glucose and lactate concentrations, low pH, and hyperosmolality. Since few studies have examined the effects of lactate and pH on HPMC biology, the present study investigated the effects of lactate and pH on the viability and proliferation of cultured HPMC and on the production of TGF-beta1, a fibrogenic cytokine, and fibronectin by cultured HPMC. HPMC were obtained from the omental tissue of pregnant women who were undergoing Cesarean section. Cells at confluence were utilized to determine the viability(LDH release), proliferation([3H]-thymidine incorporation), and the production of fibronectin and TGF-beta1(ELISA) after synchronizing the cell growth by incubating with serum free media for 24 hours. After exposure to the media containing lactate and pH, LDH release increased in dose- and time-dependent manner. Both 1.5% and 4.25% commercial PD solutions were cytotoxic and induced more than 80% LDH release within 24 hours. LDH release decreased with increasing dilution of commercial peritoneal dialysate, but there was no significant difference in LDH release between 1.5% and 4.25% PDS. LDH release increased in response to pH 5.5. Thymidine incorporation assay revealed that lactate and low pH significantly inhibited proliferation of HPMC. ELISA revealed that exposure of HPMC to lactate and low pH decreased fibronectin protein synthesis, when compared to cell exposed to bicarbonate containing M199 media. Our results clearly show that lactate and low pH lead to dose- and time-dependent cell death and reduce proliferation of cultured HPMC. Lactate and low pH per se appear to decrease fibronectin production by HPMC but may set a stage for other factors to promote progressive fibrosis during the healing stage in long-term PD.

A Case of Myelodysplastic Syndrome in a Renal Transplant Recipient / 대한신장학회잡지

A 44-year-old man treated with azathioprine, cyclosporine and prednisolone for 7.5 years after allogeneic renal transplantation was admitted because of exertional dyspnea, fatigue and pancytopenia which were found 3 months ago. He had been on hemodialysis for renal failure of unknown cause for 8 months before the renal transplantation. Bone marrow examination showed hypercellularity, erythroid hyperplasia and 7% of myeloblast, consistent with the diagnosis of myelodysplastic syndrome. Cytogenetic study showed chromosomal abnormalities:deletion of chromosome 5, monosomy 7, trisomy 8, monosomy 14 and deletion of chromosome 17. Immunosuppressive agents were discontinued and he was treated with transfusion, G-CSF, and combination chemotherapy including topotecan and Ara-C. Graft kidney function was normal before and after the treatment, but the clinical course was fatal because of leukemic transformation and eventually sepsis. Although therapy induced myelodysplastic syndrome was rare in renal allograft recipients, thorough evaluations including bone marrow biopsy and cytogenetic study are recommended in patients with anemia of unknown etiology.

Detection of Cytomegalovirus Infection and IE Gene Variants in Renal Transplant Recipients by Shell Vial Culture and DNA Methods / 대한신장학회잡지

Cytomegalovirus (CMV) is a ubiquitous virus and its infections occur commonly after renal transplantation and immunosuppressive therapy. Early and accurate laboratory diagnosis of CMV infection in renal transplant is necessary but often difficult. To find optimal diagnostic methods for CMV infection, we compared shell vial culture and polymerase chain reaction (PCR) and Southern blot of PCR products. A total of 301 specimens of urine, blood neutrophils, tissues, or body fluids were obtained from 75 renal transplant recipients and were submitted to shell vial culture for CMV as well as DNA PCR using primers for immediate early(IE) gene of CMV. The human fibroblast cell line (MRC-5) was used to culture CMV and were examined with immunofluorescence staining using monoclonal antibody to the early antigen of CMV. The PCR products (274 and 379 bp) were detected by gel electrophoresis and ethidium bromide staining. When PCR products were not clearly visible on electrophoresis, PCR products were analyzed by Southern blot using IE gene probe. Sixty four(85.3%) of 75 renal transplant recipients showed CMV infection as analyzed by PCR and Southern blot as well as shell vial culture. On shell vial culture, CMV were detected in 81 specimens from 30(40%) renal transplant recipients in viremic state. On PCR and Southern blot analysis CMV were detected in 55 and 26 specimens, respectively from 59 patients. The sensitivity of culture and PCR to detect CMV infection were 42.4% and 83.3%, respectively. The results of two studies were concordant in 48%. PCR and Southern blot did not detect CMV in 10 and 5 culture proven CMV positive samples, respectively. Mutant CMV were found in 3 patients which showed 5-10 bp deletion in IE gene. Moreover, DNA sequencing analysis showed 5 mutant strains among 11 strains which appeared same by PCR prodcut. These results suggest that PCR followed by Southern blot may be more sensitive, but less specific than shell vial culture in the diagnosis of CMV disease. PCR followed by Southern blot may not detect mutant CMV. Combined analysis using both shell vial culture and PCR followed by Southern blot may be necessary to diagnose CMV infection in renal transplant recipients.

The Effect of rhEPO on Anemia in 5/6 Nephrectomized Rats / 대한신장학회잡지

Anemia is a common clinical feature in chronic renal failure(CRF) patients. The primary cause of anemia in CRF is a deficiency of erythropoietin which is normally produced in the kidney. Erythropoietin therapy for correcting anemia has greatly increased the well-being of CRF patients and decreased cardiac morbidity. In Korea approximately 40% of CRF population on maintenance dialysis are using recombinant human erythropoietin(rhEPO). Commercially available rhEPO used in Korea is imported from abroad. Recently LG Chemical Co., produced rhEPO. In this study we evaluated the effect of LG-rhEPO on anemia in 5/6 nephrectomized rats. A total of 23 normal male Sprague-Dawley rats were used. A two-stage 5/6 nephrectomy was performed under ether anesthesia in 15 rats(group 1), additional 4 rats underwent sham operation(group 2). 4 normal rats served as normal control(group 3). rhEPO was injected subcutaneously 8 weeks after surgery. To evaluate the dose effect of rhEPO 250 IU/kg/day was injected in 2 rats, 500IU/kg/day in 4 rats, and 1000 IU/kg/day in 4 rats in group 1. To exclude the effect of LG-rhEPO vehicle, PBS, the same amount of PBS was injected in 4 rats in group 1. One rat each in groups 2 and 3 received rhEPO 250 IU/kg/day, 500 IU/kg/day, 1000 IU/kg /day, and PBS. rhEPO or PBS were injected daily in the first week, every other day in the second week and twice a week in the third week. Body weight and hematocrit level were observed weekly for the initial 8 weeks of observation period and then every other day for 3 weeks of injection and 1 week after discontinuation of injection, and BUN level every week during the study period. Body weight progressively increased in 3 groups. BUN level increased 1 week after 5/6 nephrectomy in group 1 and was stable in group 2 and 3. Hct level was significantly lower after 2 weeks of nephrectomy in group 1. Hct decreased transiently for the first week after sham operation and then returned to the baseline value in group 2. No significant change in Hct level was observed in group 3. After injection of rhEPO, Hct level increased significantly at 2 days in all 3 groups. Hct level increased significanly at 2 days in all 3 groups. Hct did not change in 3 groups with PBS injecion. In conclusion LG-rhEPO is effective in correcting anemia in animal model of CRF. A further study to evaluate the effect rhEPO on anemia in CRF patients and longterm consequences are required.

Incidence of Hypercalcemia in Dialysis Patients: HD vs. CAPD / 대한신장학회잡지

Oral phosphate binders and high calcium dialysate have been used as standard therapies for dialysis patients to prevent renal osteodystrophy. Calcium containing phosphate binders are used to prevent intestinal absorption of dietary phosphate and to avoid aluminum loading by using aluminum containing phosphate binders. The use of calcium products resulted in hypercalcemia in a substantial portion of dialysis population. Calcium carbonate as a phophate binder is widely used in Korea. However, the incidence of hypercalcemia in Korean dialysis patients has not been reported to date. In this study we evaluated the incidence of hypercalcemia in dialysis patients. Patients with associated diseases that may influence serum calcium level were excluded from the study. A total of 180dialysis patients (116 HD patients and 64 CAPD patients) maintained at Soon Chun Hyang University Hospital were included. Three consecutive 2 monthly measurements of serum calcium, phosphate, albumin, alkaline phosphatase, bicarbonate in HD and two consecutive measurements in 3 month interval in CAPD patients were retrospectively evaluated. Ionized calcium and intact parathyroid hormone (N-terminal) were measured every 6 months. Serum total calcium level was corrected by serum albumin level. Three HD patients(2.5%) were hypercalcemic pre-HD while 50(43.1%) hypercalcemic postdialysis. 5 CAPD patients(7.8%) were hypercalcemic. Pre-HD calcium level did not differ from the value in CAPD patients. An average value of pre-and post-HD calcium, and serum albumin levels were significantly higher in HD patients than those values in CAPD patients(p<0.01). Ionized calcium (p<0.01) and serum PTH(p<0.05) levels were significantly higher, while serum bicarbonate level (p<0.01) was significantly lower in HD patients than in CAPD patients. The amount of calcium carbonate used were 2.2g in HD and 2.8g in CAPD. In conclusion, the incidence of hypercalcemia is low in pre-HD (2.5%) and in CAPD patients(7.8%). However, the high incidence of post-HD hypercalcemia observed in this study advocates a future study to evaluate the effect of low calcium dialyste on calcium-phosphate metabolism.

Acquired Cystic Kindey Disease in Dialysis and Renal Transplant Patients: Ultrasonography and CT Analysis

PURPOSE: To evaluate by US and CT the incidence and complications of acquired cystic kidney disease (ACKD) in dialysis and renal transplant patients and to compare the effectiveness of US and CT in the diagnosis of this entity. MATERIALS AND METHODS: This study was prospectively performed in 70 dialysis patients and 13 renal transplant patients, and excluded any with multiple renal cysts or polycystic kidney disease, on as seen on initial films. US were obtained in all patients, and CT scans were randomly obtained in 27 who had been on dialysis for 3 years or more; all these US and CT scans were analyzed, with particular emphasis on whether or not cysts were present. In order to correlate the numbers of cysts with duration of dialysis, all patients were assigned to one of three groups, according to the number of cysts found (group 1, 0; group 2, 1-4; group 3, >4).Only group 3 was diagnosed as suffering from ACKD. In order to compare the cyst-detection capability of US with that of CT, 27 dialysis patients who had undergone US and CT were divided into four groups according to the numberof cysts found (grade 1, 0; grade 2, 1-4; grade 3, 5-10; grade 4, >10). RESULTS: Seventy dialysis patients were divided according to the results of US, as follows : group 1, 20%; group 2, 47.1%; group 3, 32.9%. The mean duration of dialysis in group 1 (31.9 months) was statistically different from that in group 2 (50.6 months) and in group 3 (95.8 months) (p<0.000). Thirteen renal transplant patients were divided as follows : group1, 61.5%; group 2, 38.5%; group 3, 0%. In dialysis patients with ACKD, complications noted were renal cell carcinoma(n=1), hemorrhagic cysts(n=2), and hematomas(n=2) Among the 27 dialysis patients who underwent CT, this and US showed an equal grade of cystic change in 53.7%, while CT showed a higher grade in 46.3%. The detection rate of ACKD in these 27 patients was 46% on US and 63% on CT. CONCLUSION: A prolongation of dialysis corresponded to an increased incidence of ACKD; renal neoplasm and hemorrhage may occur in dialysis patients, but ACKD and its complications did not develop in renal transplant patients. In long-term dyalysis patients, regular follow-up studies of kidneys using US or CT are therefore needed. CT was superior to US in diagnosing ACKD.

A Case of Primary Aldosteronism, Nephrotic Syndrome and Chronic Renal Failure: A Diagnostic Dilemma / 대한신장학회잡지

Primary aldosteronism is characterized by hypertension, hypokalemia, low plasma renin activity (PRA) and elevated plama aldosterone (PA) level. Primary aldosteronism is suspected in patients with hypertension and unexplained hypokalemia. In chronic renal failure(CRF), however, renin-angiotensin-aldosterone axis is altered by renal disease per se, antihyppertensive drugs used and volume status. Therefore, it is difficult to diagnose primary aldosteronism in CRF on the basis of serum potassium, PRA and PA level. Recently, we experienced a case of primary aldosteronism associated with nephrotic syndrome and CRF. The patient was a 49 years old woman who presented with 10 year old history of high blood pressure and general weakness of one year's duration. Her initial serum creatinine was 7.3mg/dL and serum potassium 2.6mEq/L. PRA was decreased and PA was markedly increased. Persistent hypokalemia urged to evaluate adrenal gland in this case. The round mass was found in left adrenal gland and it was surgically removed. CRF and nephrotic syndrome can alter serum potassium and PRA and there lies the diagnostic dilemma for primary aldosteronsim. It will be well to consider associated primary alodsteronism in a patient with CRF and persistent hypokalemia.

Characteristics of Convective Transport of Glucose During Peritoneal Dialysis / 대한신장학회잡지

The sieving coefficient(S) representing convective transport of glucose during peritoneal dialysis(PD) with glucose containing dialysis solution has been reported to be anomalous, lower than 0 or higher than 1. During peritoneal dialysis using glucose containing dialysis solution, diffusive transport of glucose is from dialysate to blood, and convective transport in the opposite direction i.e., from blood to dialysate. Glucose intolerance and hyperinsulinemia are well known adverse effects of PD using glucose containing dialysis solutions. Insulin is required for glucose transport from extracelluar fluid to intracelluar fluid in adipocytes and muscell cells. Hyperinsulinemia in PD may alter peritoneal glucose transport. If extra to intracellular glucose transport mediated by insulin is involved in the peritoneal glucose transport during PD with conventional glucose containing dialysis solutions, the diffusive and convective transport characteristics for glucose calculated using membrane model between two well-mixed compartments may not represent true values. S can be calculated best when diffusion is minimized. Male Sprague-Dawley rats were used. To minimize the diffusive transport the glucose isochratic solutions containing approximately the same concentration as in serum were used. To maximize ultrafiltration 3.86% mannitol was used as an osmotic agent. To evaluate the effect of insulin on glucose transport two different glucose concentrations, 100mg/dl(NI) and 300mg/dl(HI), were used. During the dialysis with HI solution glucose clamp technique was performed to keep blood glucose level approximately 300mg/dl. A 2 hour peritoneal dialysis was performed in 13 rats(7 Nl and 6 Hl). Serum and dialysate insulin levels were measured in 3rats in Nl, 2 rats in Hl, and 4 rats without dialysis(NC). Intraperitoneal volume(VD) was calculated using volume marker, RISA, dilution method. The diffusive mass transport coefficient(KBD) and S for urea and glucose were calculated using the modified Babb- Randerson-Farrell model. D/P glucose in Nl was 0.61+/-0.05 due to high blood glucose level 187.2+/-17.9mg/dl vs. 114.3+/-7.6 mg/dl in dialysate and 0.99+/-0.26 in Hl(360.6+/-55.6mg/dl in blood vs. 345.0+/-55.6mg/dl in dialysate). VD did not differ between the two groups. KBD for urea and glucose, and S for urea did not differ between the two groups. S for glucose in Hl was negative value and significantly lower than that in Nl(-0.903+/-0.960 vs. 1.036+/-0.137, P<0.001). Plasma insulin level was significantly higher in Hl compared with values in Nl and NC. Dialysate insulin level was similar in Nl and Hl. Dialysate insulin level in Nl was higher than plasma insulin level. The present result that S for glucose at hyperinsulinemic condition was anomalous indicates that not only simple passive transport but also other transport mechanisms mediated by insulin such as glucose influx into cells may be involved in peritoneal glucose transport. The finding of dialysate insulin level higher than plasma concentration in Nl may suggest direct leakage of insulin from pancreas or portal vein into the peritoneal cavity.