Characterization of Adult Canine Kidney Epithelial Stem Cells That Give Rise to Dome-Forming Tubular Cells.

Dome formation can occur in cultured tubular epithelial cells originating from various tissues, including the mammary gland and the kidney. The isolation and characterization of normal kidney epithelial stem cells that give rise to dome-forming tubular cells have never been reported. We attempted to isolate and characterize canine kidney epithelial stem cells using a simple cell culture method that we have previously used to isolate other adult human stem cells. Dome-forming kidney epithelial cells were derived from dissociated adult canine kidney tissues that were cultured in a modified keratinocyte serum-free medium supplemented with N-acetyl-l-cysteine, l-ascorbic acid 2-phosphate, nicotinamide, and fetal bovine serum. These cells exhibited high self-renewal capacity in long-term culture (growth for >13 months and 30 cumulative population doublings) and exhibited characteristics of stem cells, including (1) deficiency in gap junctional intercellular communication, (2) anchorage-independent growth, (3) expression of stem cell markers octamer-binding transcription factor 4 and SRY (sex determining region Y)-box 2, (4) expression of cell surface markers CD24 and CD133, and (5) multipotent differentiation into osteoblasts, adipocytes, chondrocytes, and dome-forming tubular cells. Most of these characteristics are shared by the well-known canine renal tubule-derived immortalized Madin-Darby Canine Kidney cell line. Furthermore, the putative canine kidney stem cells developed in this study formed budding tubule-like organoids on Matrigel and required high cell density (>4,000 cells/cm2) for sustained growth and confluency for dome formation. The signal transducer and activator of transcription-3 (STAT3) phosphorylation inhibitor, AG490, inhibited colony-forming efficiency and dome formation, whereas lipopolysaccharide, an activator of STAT3, increased colony-forming efficiency in a dose-dependent manner. These results are consistent with the hypothesis that high cell density induces STAT3 expression, which promotes both stem cell self-renewal and differentiation into tubular cells. Our novel cell culture method should be useful for the future development of normal human kidney stem cells for clinical applications and for studying mechanisms of nephrotoxicity.

Urinary Uromodulin/Creatinine Ratio as a Potential Clinical Biomarker for Chronic Kidney Disease Patients with Gout: A Pilot Study.

OBJECTIVE: Recent studies have reported that reduced excretion of urinary uromodulin is associated with renal tubular function and risks of progressive kidney disease. Gouty nephropathy is usually seen in patients with gout. Patients with chronic gouty nephropathy are characterized by the deposition of monosodium urate crystals primarily involving the collecting ducts in the medulla. We postulated that this correlation may be specific to gout and may serve as a useful biomarker for chronic kidney disease (CKD). MATERIALS AND METHODS: A total of 114 Taiwanese patients diagnosed with gout (n = 72), CKD (n = 26), or healthy volunteers (n = 16) were prospectively enrolled for this study from the Rheumatology and Nephrology Outpatient Clinics of our institution. We obtained urine and blood samples on patient visits to the outpatient clinics. Demographic data were obtained from medical records. RESULTS: In patients with gout, the spot urinary uromodulin/creatinine ratio (uUMCR; mg/g) in patients with CKD was significantly lower than that in those without CKD (CKD group: 2.2; non-CKD group: 5.6, p = 0.005). Multivariate analysis revealed that patients with CKD and gout had a lower uUMCR than those with gout alone (p = 0.028). A significant association was not observed in our non-gout cohort. CONCLUSION: The association of decreased uUMCR with CKD status was identified only in patients with gout in the present study. We believe that uUMCR might serve as an indicator of differential CKD in patients with gout.

Nosocomial extended-spectrum beta-lactamase-producing Klebsiella pneumoniae bacteremia in hemodialysis patients and the implications for antibiotic therapy.

BACKGROUND: In the face of increasing treatment options for extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-Kp) hemodialysis (HD) access-related bacteremia, the difference in clinical effectiveness between ertapenem and flomoxef remains unclear. We conducted this retrospective study to determine their efficacies and treatment outcomes. METHODS: Patients on maintenance HD with fistula-, graft-, or catheter-related ESBL-Kp bacteremia were enrolled. Data related to clinical features and antibiotic treatments were collected. Outcome was determined by mortality resulting from bacteremia during the 14-day period after the collection of the first positive blood culture for flomoxef-susceptible ESBL-Kp. RESULTS: The 64 patients studied had severe septicemia as determined by the Pitt bacteremia score; 50% (32/64) were in the intensive care unit (ICU) at the time of bacteremia. Old age (>65 years; 57.8%), malnutrition (albumin<3.5g/dl; 92.2%), a history of severe illnesses (defined by shock, intubation, or ICU stay; 82.5%), and prolonged hospitalization prior to the onset of bacteremia (>30 days; 75%) were also highly prevalent. The study population comprised nine fistula-, 10 graft-, and 45 HD catheter-related bacteremia cases, and the mortality rate was high (38/64, 59.4%). The mortality rate was significantly higher in the flomoxef treatment group than in the ertapenem treatment group (22/30, 73% vs. 16/34, 47%, p<0.05). Among patients with catheter-related bacteremia, multivariate analyses revealed that flomoxef use (odds ratio (OR) 2.52, 95% confidence interval (CI) 1.34-35.17) and Pitt bacteremia score (OR 4.37, 95% CI 1.28-5.26) were independently associated with mortality. CONCLUSIONS: In accordance with our previous study, our results have demonstrated the inferiority of flomoxef to carbapenems in the treatment of HD access-related ESBL-Kp bacteremia and provide an insight into the possibility of using ertapenem rather than flomoxef as an initial or de-escalating therapy for infections caused by ESBL-producing bacteria.

Association between hypertensive disorders during pregnancy and end-stage renal disease: a population-based study.

BACKGROUND: Studies into the association between hypertensive disorders during pregnancy and end-stage renal disease are limited. We investigated the risk of end-stage renal disease after delivery among women with hypertensive disorders during pregnancy. METHODS: We used insurance claims data from 1998 to 2009 to identify 26,651 women aged 19-40 years old who experienced hypertensive disorders during pregnancy; these women had no history of hypertension, diabetes, kidney disease or lupus. We also randomly selected 213,397 women without hypertensive disorders during pregnancy as a comparison cohort; the frequency was matched by age and index year of pregnancy. We compared the incidence of end-stage renal disease in the 2 cohorts. We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) after controlling for demographic and clinical factors. RESULTS: Women with hypertensive disorders during pregnancy had a greater risk of chronic kidney disease and end-stage renal disease, with adjusted HRs of 9.38 (95% CI 7.09-12.4) and 12.4 (95% CI 8.54-18.0), respectively, after controlling for urban status, coronary artery disease, congestive heart failure, hyperlipidemia and abruption. The HR for end-stage renal disease was 2.72 (95% CI 1.76-4.22) after we also controlled for hypertension and diabetes. Women with preeclampsia or eclampsia had a higher risk of end-stage renal disease (adjusted HR 14.0, 95% CI 9.43-20.7) than women who had gestational hypertension only (adjusted HR 9.03, 95% CI 5.20-15.7). INTERPRETATION: Women with hypertensive disorders during pregnancy were at a high risk of end-stage renal disease. The risk was much greater for women who had preeclampsia or eclampsia than those who had gestational hypertension only.

Impact of dialysis modality on the survival of end-stage renal disease patients with or without cardiovascular disease.

BACKGROUND: The question of which modality, either peritoneal dialysis (PD) or hemodialysis (HD), confers the survival advantage for incident ESRD patients with pre-existing cardiovascular disease (CVD) remains unanswered. METHODS: Data used in this study were extracted from the National Health Insurance Research Database in Taiwan. From 1997 to 2007, incident ESRD patients who underwent dialysis longer than three months were selected. The established dialysis modality at day 90 was used to analyze the impact of dialysis modality on survival. For each PD patient indentified, five HD patients matched for age, sex, and year in which the patients received their first dialysis treatment were randomly selected. Finally, a total of 35 664 patients including 29 720 HD patients and 5944 PD patients were selected. The primary outcome was death after commencing dialysis. RESULTS: For diabetic ESRD patients with or without coronary artery disease (CAD) or congestive heart failure (CHF), patients receiving PD had inferior survival compared with those receiving HD (P<.001, adjusted HR=1.34 to 1.43). For nondiabetic patients with CAD or CHF, patients receiving PD also had inferior survival compared with those receiving HD (adjusted HR=1.30, CI: 1.08 to 1.57; adjusted HR=1.31, CI: 1.11 to 1.55). For nondiabetic ESRD patients without CAD or CHF, there was no statistically significant difference in survival between PD and HD (adjusted HR=1.00, CI: 0.92 to 1.09; adjusted HR=0.98, CI: 0.90 to 1.07). CONCLUSIONS: PD was associated with poorer survival among ESRD patients with CVD or diabetes mellitus compared with HD.

Discrepancy between effects of carbapenems and flomoxef in treating nosocomial hemodialysis access-related bacteremia secondary to extended spectrum beta-lactamase producing Klebsiella pneumoniae in patients on maintenance hemodialysis.

BACKGROUND: Hemodialysis (HD) patients are susceptible to extended spectrum beta-lactamase (ESBL)-producing bacterial infections. Because the optimal treatment and clinical significance of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) HD access-related bacteremia remain unclear, we conducted this retrospective study to determine the clinical outcomes of patients treated with either flomoxef or a carbapenem. METHODS: The eligibility criterion was fistula or graft- or catheter- related ESBL-Kp bacteremia in patients on maintenance HD. The clinical characteristics and antibiotic management were analyzed. Outcome was determined by mortality resulting from bacteremia during the 14-day period after the first positive blood culture for flomoxef-susceptible ESBL-Kp. RESULTS: The 57 patients studied were predominantly elderly, malnourished, with a history of severe illnesses and broad-spectrum antibiotic use before the onset of bacteremia, and with severe septicemia as determined by the Pitt bacteremia score (PBS). The study population comprised 7 fistula, 8 graft, and 42 HD catheter-related bacteremia (CRB) cases, and the mortality rate was high (36/57, 63.2%) in these 57 patients. Of 42 patients with CRB, those in the deceased group (27/42, 64.3%) had significantly lower levels of serum albumin, longer prior hospital stay and duration of catheter-dependent HD, and higher PBS than patients in the survived group. Failure to receive effective antibiotics (flomoxef or a carbapenem) within 5 days after onset of bacteremia and treatment with flomoxef both significantly contributed to higher mortality. Multivariate analyses revealed that flomoxef use, PBS, and catheter-dependent HD >30 days were independently associated with increased mortality (OR, 3.52; 95% CI, 1.19-58.17, OR, 2.92; 95% CI, 1.36-6.26 and OR, 5.73; 95% CI, 1.21-63.2, respectively). CONCLUSIONS: Considering the high mortality rate, ESBL-Kp should be recognized as a possible pathogen in patients on maintenance HD at high risk of acquiring HD access infections associated with ESBL-producing bacteria. Carbapenems rather than flomoxef should be the therapy of choice in these critically vulnerable patients.

Free p-cresol sulfate is associated with survival and function of vascular access in chronic hemodialysis patients.

BACKGROUND: Protein-bound uremic toxins indoxyl sulfate (IS) and p-cresol sulfate (p-CS) have been implicated as an important factor in uremic syndrome. Recent evidence indicates that both IS and p-CS are predictors of cardiovascular as well as all-cause mortality among chronic dialysis patients. We conducted a study to analyze the relationship between IS and p-CS and vascular access (VA) outcome in chronic hemodialysis (HD) patients. METHODS: A total of 91 chronic stable HD patients were divided into groups according to survival of VA and frequency of VA dysfunction. Demographic and biochemical data were reviewed and recorded. Serum levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1, and the total and free forms of IS and p-CS were determined. RESULTS: Patients with a history of frequent VA failure and dysfunction had lower albumin and higher levels of ICAM-1, free IS, free and total p-CS. Diabetes was associated with higher IS and p-CS. Logistic regression revealed that diabetes and free p-CS were independent factors associated with poor outcome of VA. CONCLUSION: Endothelial dysfunction and uremic toxins were associated with survival and function of VA. Diabetes and free p-CS were significantly related to the outcome of VA among chronic HD patients.

Risks, subtypes, and hospitalization costs of stroke among patients with systemic lupus erythematosus: a retrospective cohort study in Taiwan.

OBJECTIVE: To compare risks, subtypes, and hospitalization costs of stroke between cohorts with and without systemic lupus erythematosus (SLE). METHODS: From the catastrophic illnesses registry of Taiwan's universal health insurance claims data, we identified 13,689 patients with SLE diagnosed in 1997-2008 and selected 54,756 non-SLE controls, frequency-matched with age (every 5 years), sex, and index year. Age-specific and type-specific stroke incidence, hazard, and cost of stroke were compared between the 2 cohorts to the end of 2008. RESULTS: Compared with the non-SLE cohort, the risk of stroke was 3.2-fold higher in the SLE cohort (5.53 vs 1.74 per 1000 person-years) with an overall adjusted HR of 2.90 (95% CI 2.52-3.33). The age-specific risk was the highest in patients 1-17 years old (HR 163, 95% CI 22.2-1197) and decreased as age increased (p = 0.004). Hypertension and renal disease were the most important comorbidities in the SLE cohort predicting stroke risk (HR 1.75, 95% CI 1.28-2.39 and HR 1.66, 95% CI 1.32-2.10, respectively). There were more hemorrhagic strokes in the SLE cohort than in the non-SLE cohort, but not significantly (28.0% vs 23.4%; p = 0.10). The hospitalization cost for stroke patients was more than twice the cost for those with SLE than for those without (p < 0.0001). CONCLUSION: Stroke risk and hospital care costs are considerably greater for patients with SLE than without. The relative risk of stroke is the highest in young patients with SLE.

Refractory Salmonella enterica serotype choleraesuis-related renal cyst infection in a patient with autosomal dominant polycystic kidney disease undergoing hemodialysis treated successfully with intracystic ciprofloxacin infusion.

OBJECTIVE: To report a potential salvage therapy for refractory renal cyst infection secondary to Salmonellaenterica serotype choleraesuis (S. choleraesuis). CLINICAL PRESENTATION AND INTERVENTION: A 52-year-old male with autosomal dominant polycystic kidney disease undergoing hemodialysis experienced an episode of S. choleraesuis-related gastroenteritis subsequently complicated by bloodstream and refractory renal cyst infection with formation of multiple pyocysts. The patient was treated with intracystic indwelling diluted ciprofloxacin solution. CONCLUSION: In this patient, intracystic infusion of ciprofloxacin achieved a sufficient antibiotic level in infected renal cysts and hence completely eradicated S. choleraesuis. Therefore, intracystic antiobiotic infusion could be a potential salvage therapy for refractory renal cyst infection.

Bacteremia in hemodialysis and peritoneal dialysis patients.

OBJECTIVE: To analyze the incidence rates and risk factors for bacteremia in patients undergoing hemodialysis (HD) and peritoneal dialysis (PD). METHODS: The records of 898 consecutive patients undergoing dialysis from January 2003 to December 2008 were reviewed retrospectively. Episodes of bacteremia were recorded. China Medical University (Taichung, Taiwan). RESULTS: The overall incidence rate of bacteremia was 7.63 per 100 patient-years in HD patients and 3.56 per 100 patient-years in PD patients and it was higher in HD patients each year from 2003 to 2008. S. aureus (27.53%) was the most common pathogen in HD patients, whereas Coagulase-negative Staphylococcus (21.3%) was the most common pathogen in PD patients. Vascular access infection was the most common etiology in HD patients, whereas peritonitis was the most common etiology in PD patients. Older age, shorter dialysis vintage, use of HD rather than PD, current smoker, use of a venous dialysis catheter, presence of diabetes mellitus, higher comorbidity score, and lower serum albumin were significant risk factors for bacteremia. Diabetes mellitus and lower serum albumin were significant risk factors for bacteremia-associated mortality. CONCLUSION: Placement of a permanent access (fistula, graft, or PD catheter) prior to initiation of dialysis, smoking cessation, and better nutritional status (i.e. higher serum albumin) were associated with a reduced risk of bacteremia in dialysis patients. Higher serum albumin was also associated with a reduced bacteremia-associated mortality.

Hypertensive disorders in pregnancy and subsequent diabetes mellitus: a retrospective cohort study.

BACKGROUND: Cohort study on the association between hypertensive disorders in pregnancy (HDP) and postpartum diabetes is limited. This retrospective cohort study investigated the incidence of diabetes mellitus after delivery among women with HDP using claims data of a universal insurance system. METHODS: We defined the HDP group as women aged 19-40 years with their first HDP in 2003, excluding those with a history of gestational diabetes mellitus, diabetes mellitus, or hypertension before the date of diagnosis with HDP. Women who had normal pregnancy without HDP were randomly chosen as our comparison group, frequency matched with age and index year of the HDP group. Both groups were followed until December 31, 2008 to evaluate the occurrence of diabetes. RESULTS: This study consisted of 1139 women with HDP cases and 4527 non-HDP pregnant women. Overall, the subsequent incidence of diabetes mellitus was 5.08-fold higher in the HDP group than in the non-HDP group, with an adjusted hazard ratio of 3.42 (95% confidence interval [CI], 2.07-5.64) after controlling for age, occupation, income, and comorbidity. The hazard ratio of developing diabetes increased to 39.5 (95% CI, 13.0-120.6) for women having HDP, hyperlipidemia, and obesity simultaneously. CONCLUSIONS: Women with HDP have a high risk of subsequent diabetes. HDP women with obesity and hyperlipidemia are at an extremely high risk of diabetes mellitus. Early identification of women with HDP is needed for prevention, particularly those with other comorbidities.

Real-time PCR analysis of the intestinal microbiotas in peritoneal dialysis patients.

Bifidobacterium and Lactobacillus can beneficially affect the host by producing acetic acid and lactic acid, which lower pH and thereby inhibit the growth of pathogens or allow the probiotic bacteria to compete with pathogens for epithelial adhesion sites and nutrients. The transmural migration of enteric organisms into the peritoneal cavity can cause peritonitis in peritoneal dialysis (PD) patients. We hypothesized that the composition of the intestinal microbiota with regard to Lactobacillus species and Bifidobacterium species differed between PD patients and healthy controls. The aim of the study was to investigate these differences by real-time PCR analysis of fecal samples. From 1 August 2009 to 31 March 2010, a total of 29 nondiabetic PD patients and 41 healthy controls from China Medical University Hospital were recruited after giving their informed consent. Fecal samples were collected from the PD patients and their age-matched counterparts in the morning using a standardized procedure. DNA extracted from these samples was analyzed by real-time PCR. All bifidobacteria, Bifidobacterium catenulatum, B. longum, B. bifidum, Lactobacillus plantarum, L. paracasei, and Klebsiella pneumoniae were less frequently detected in the patient samples. Dysbiosis (microbial imbalance) may impair intestinal barrier function and increase host vulnerability to pathogen invasion. Further studies are necessary to confirm our findings before clinical trials with probiotic supplementation in PD patients.

Clinical safety and anticoagulation efficacy of low-molecular-weight heparins in chronic hemodialysis patients: a single medical center experience.

BACKGROUND: In many countries low-molecular-weight heparins (LMWHs) are increasingly used for hemodialysis (HD). Low-range activated clotting time (ACT-LR) values and anti-Xa activity had been used to monitor the degree of anticoagulation caused by LMWH. However, the facilities are not easily available at most hospitals. Such data are limited in Taiwan. METHODS: A total of 76 patients receiving maintenance HD were prospectively enrolled. The HD patients were randomized to receive either nadroparin or enoxaparin and checked the ACT-LR values and anti-Xa activity. We aimed to analyze ACT-LR values and anti-Xa activity along with the clotting of the dialyzer or bleeding events associated with two LMWHs after they were administered. We also aimed to determine the dose necessary to reach maximum safety and efficacy. RESULTS: We found no significant differences in LMWH dosage, ACT-LR values, and anti-Xa activity between the two groups. There were no significant differences in bleeding/adverse events and extracorporeal circuit thrombosis between the two groups. Most of the bleeding and adverse events were subcutaneous minor bleeding. No major bleeding or mortality was found. We found significant differences in mean dosage, cost, bleeding/adverse effect, and extracorporeal circuit thrombosis between excessive and reduced nadroparin dosage groups. CONCLUSION: LMWH is not still routinely used due to its high cost in Taiwan. In our clinical experience, nadroparin and enoxaparin exhibited high levels of safety and efficacy in chronic HD patients. Reduced LMWHs dosage could promote patient's safety and decreased HD cost in HD patients with excessive dosage of LMWHs.

Urinary UMOD excretion and chronic kidney disease in gout patients: cross-sectional case-control study.

Patients with gout often have concurrent chronic kidney disease (CKD); the relationship between the two conditions is still unclear. Previous studies have identified an association between low level of urinary uromodulin (UMOD) and CKD within the setting of diabetes and lupus. The aim of this study was to examine the association between urinary UMOD excretion and CKD in patients with gout. A total of 53 Taiwanese gout patients with stable disease activity were enrolled. Patients were divided into a CKD group (n = 25) and a non-CKD group (n = 28). Using Pearson correlation analysis, urinary UMOD excretion was positively correlated with estimated glomerular filtration rate (Ha: ρ > 0, p = 0.004). Using multivariate analysis, patients with CKD and gout were associated with lower urinary UMOD excretion than those who have gout alone [odds ratio (95% CI): 0.826 (0.694-0.985), p < 0.001]. Patients with CKD and gout were also more likely to be older (p < 0.001) and have higher uric acid levels (p < 0.001). This study implicates that UMOD might play a role in the relationship between gout and CKD. Further studies with animal models of gout and CKD would be recommended.

Low-molecular-weight heparin successfully used to treat a nephrotic patient complicated by superior mesenteric vein thrombosis and portal vein thrombosis.

OBJECTIVES: To report the success of treatment with low- molecular-weight heparins (LMWHs) in a case of nephrotic syndrome complicated by mesenteric vein thrombosis (MVT) and portal vein thrombosis (PVT). CLINICAL PRESENTATION AND INTERVENTION: A 53-year-old man with nephrotic syndrome developed persistent mild abdominal pain for 3 days. Hepatic-portal venous system thrombosis of nephrotic syndrome was suspected due to new-onset superficial vein engorgement of the abdomen without liver cirrhosis. Abdominal computed tomography revealed MVT concomitant with PVT. He was successfully treated with LMWH without thrombolytic therapy. After discharge on day 9, he received continuous anticoagulation by LWMH on an outpatient basis at the nephrology clinic. Venous thromboembolic events or proteinuria did not recur within the 6-month follow-up. CONCLUSION: This report showed a case of MVT concomitant with PVT, a critical complication of nephrotic syndrome that was diagnosed in time and successfully treated with LMWH. A high index of clinical suspicion and timely management are crucial to tackle thrombotic complications in nephrotic syndrome.

Hypertensive disorders in pregnancy and preterm delivery and subsequent stroke in Asian women: a retrospective cohort study.

BACKGROUND AND PURPOSE: Few studies exist concerning the risk of stroke associated with hypertensive disorders in pregnancy (HDP) in Asian women. This study investigates whether preterm delivery further complicates this risk in women with HDP in Taiwan. METHODS: Based on universal insurance claims data, 1092 pregnant women with newly diagnosed HDP from 2000 to 2004 and aged 15 to 40 years were identified as the HDP cohort. Then, 4715 randomly selected persons without HDP frequency matched with the index year were designated as the non-HDP controls. Both cohorts were followed-up until the end of 2008 to measure the incidence of stroke. RESULTS: The HDP cohort had a higher incidence of stroke than the non-HDP cohort (30.1 vs 12.8 per 10 000 person-years), with an overall adjusted hazard ratio of 2.04 (95% CI, 1.18- 3.51) for stroke. Preterm delivery increased the risk of stroke to 3.22-fold (95% CI, 1.48-6.99; P for trend=0.002). The age-specific V-shape risk association showed that the highest risk of stroke was noted among subjects 15 to 18 years old in the HDP group (hazard ratio, 13.4; 95% CI, 1.54-116.7) and followed by women aged 35 years and older (hazard ratio, 5.56; 95% CI, 1.47-21.0). CONCLUSIONS: Pregnant women with HDP have an increased risk of subsequent stroke. Preterm delivery and older ages increase the risk of subsequent stroke. Adolescents with HDP also have an elevated risk of stroke. Early identification of women with HDP is needed for prevention.