Seung Seok Han

Seoul National University Hospital, Sŏul, Seoul, South Korea

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Publications (27)58 Total impact

  • Seung Seok Han, Dong Ki Kim, Kook-Hwan Oh, Yon Su Kim
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    ABSTRACT: Peritoneal dialysis (PD) is one potential treatment option for patients starting dialysis after graft loss (DAGL). However, the infectious outcomes and their associations with steroid use remain undetermined in these patients. A total of 41 DAGL patients undergoing PD were recruited. The patients were divided into low- and high-dose steroid groups according to the median level. Additionally, they were categorized into tapering and nontapering groups, for which the tapering regimen was defined as the withdrawal of steroids within 1 year after starting PD. Primary outcomes, such as peritonitis and exit site infection (ESI), were compared between DAGL and 712 transplant-naive (TN) patients. The overall risk of peritonitis was similar between the TN and DAGL groups. However, when the DAGL group was stratified by the steroid variable, the risk was higher in the high-dose or nontapering steroid groups than in the TN or counterpart steroid groups. The DAGL group had a higher risk of ESI than the TN group, irrespective of steroid dose. When the analysis was stratified by tapering regimen, the difference in ESI risks was seen only in the nontapering group and the TN group; the tapering group had a similar risk of ESI as that of the TN group. The present study first addresses the risks of peritonitis and ESI together and then raises awareness of the high risk that should be considered after using high-dose steroids or the nontapering regimen in the DAGL patients.
    Transplantation 01/2015; DOI:10.1097/TP.0000000000000573 · 3.78 Impact Factor
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    ABSTRACT: Both acute kidney injury (AKI) and chronic kidney disease (CKD) are important issues in patients undergoing coronary artery bypass grafting (CABG), particularly with regard to mortality. However, their synergistic or discrete effects on long-term mortality remain unresolved. A total of 1,899 patients undergoing CABG were retrospectively analyzed. The adjusted hazard ratios for all-cause mortality were calculated after stratifying the timeframes. To evaluate the synergistic effects between AKI and CKD, the relative excess risk due to interaction was applied. The presence of AKI, CKD, or both increased the hazard ratios for mortality, compared with the absence of both: AKI alone, 1.84 (1.464-2.319); CKD alone, 2.46 (1.735-3.478); and AKI and CKD together, 3.21 (2.301-4.488). However, the relationships with mortality were different between AKI and CKD, according to the timeframes: AKI primarily affected early mortality, particularly within 3 years, whereas CKD had a relatively constant effect on both the early and late periods. When the parameters from the relative excess risk due to interaction were obtained, there was a synergistic additive effect on early mortality between AKI and CKD. The relationships with mortality after CABG were different between AKI and CKD. However, their effects were not exclusive but synergistic. Copyright © 2015 Elsevier Inc. All rights reserved.
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    ABSTRACT: Echocardiographic parameters can predict cardiovascular events in several clinical settings. However, which echocardiographic parameter is most predictive of each cardiovascular or non-cardiovascular event in patients starting hemodialysis remains unresolved. Echocardiography was used in 189 patients at the time of starting hemodialysis. We established primary outcomes as follows: cardiovascular events (ischemic heart disease, cerebrovascular disease, peripheral artery disease, and acute heart failure), fatal non-cardiovascular events, all-cause mortality, and all combined events. The most predictable echocardiographic parameter was determined in the Cox hazard ratio model with a backward selection after the adjustment of multiple covariates. Among several echocardiographic parameters, the E/e' ratio and the left ventricular end-diastolic volume (LVEDV) were the strongest predictors of cardiovascular and non-cardiovascular events, respectively. After the adjustment of clinical and biochemical covariates, the predictability of E/e' remained consistent, but LVEDV did not. When clinical events were further analyzed, the significant echocardiographic parameters were as follows: s' for ischemic heart disease and peripheral artery disease, LVEDV and E/e' for acute heart failure, and E/e' for all-cause mortality and all combined events. However, no echocardiographic parameter independently predicted cerebrovascular disease or non-cardiovascular events. In conclusion, E/e', s', and LVEDV have independent predictive values for several cardiovascular and mortality events.
    Journal of Korean Medical Science 01/2015; 30(1):44-53. DOI:10.3346/jkms.2015.30.1.44 · 1.25 Impact Factor
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    ABSTRACT: The inverse relationship between 25-hydroxyvitamin D [25(OH)D] status and insulin resistance (IR) has been reported, but many interventional studies failed to reduce IR with 25(OH)D supplementation. In addition, there has been a paucity of literature on the interaction between 25(OH)D status and IR according to the degree of obesity in Asian subjects. We therefore evaluated the association between 25(OH)D status and IR according to the degree of obesity. Data from the Korea National Health and Nutrition Examination Survey in 2008-2010 were analyzed. The study subjects comprised 10,629 participants aged ≥ 20 years with fasting glucose < 100 mg/dL. IR was estimated by the homeostasis model assessment (HOMA). We found an inverse linear association between 25(OH)D and loge(HOMA-IR) in multiple linear regression analysis; namely, 10 ng/mL increase of 25(OH)D was associated with 0.018 decrease of loge(HOMA-IR) (p < 0.0001). In the subgroup analysis, we identified a distinct trend that the inverse linear association between 25(OH)D and loge(HOMA-IR) became more prominent with the progression of body mass index, waist circumference, or fat mass quartile (Q): -0.009, -0.004, -0.029 and -0.037 in Q1-Q4 of body mass index, -0.004, -0.014, -0.02 and -0.038 in Q1-Q4 of waist circumference, and -0.002, -0.001, -0.017 and -0.025 in Q1-Q4 of fat mass. Thus, the IR-lowering effect of 25(OH)D became more evident with the progression of obesity in an adult Korean population without increased fasting glucose levels. We suggest that proper supplementation of vitamin D might be beneficial in obese Korean adults.
    The Tohoku Journal of Experimental Medicine 10/2014; 234(2):89-97. DOI:10.1620/tjem.234.89 · 1.37 Impact Factor
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    ABSTRACT: Vitamin D deficiencies and increases in urinary albumin excretion (UAE) are both important and potentially related health problems; however, the nature of their relationship has not been established in normoalbuminuric subjects.
    BMC Nephrology 06/2014; 15(1):97. DOI:10.1186/1471-2369-15-97 · 1.52 Impact Factor
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    ABSTRACT: BackgroundProteinuria and hematuria are both important health issues; however, the nature of the association between these findings and acute kidney injury (AKI) or mortality remains unresolved in critically ill patients.MethodsProteinuria and hematuria were measured by a dipstick test and scored using a scale ranging from a negative result to 3+ in 1883 patients admitted to the intensive care unit. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. The odds ratios (ORs) for AKI and 3-year mortality were calculated after adjustment for multiple covariates according to the degree of proteinuria or hematuria. For evaluating the synergistic effect on mortality among proteinuria, hematuria, and AKI, the relative excess risk due to interaction (RERI) was used.ResultsProteinuria and hematuria increased the ORs for AKI: the ORs of proteinuria were 1.66 (+/−), 1.86 (1+), 2.18 (2+), and 4.74 (3+) compared with non-proteinuria; the ORs of hematuria were 1.31 (+/−), 1.58 (1+), 2.63 (2+), and 2.52 (3+) compared with non-hematuria. The correlations between the mortality risk and proteinuria or hematuria were all significant and graded (Ptrend < 0.001). There was a relative excess risk of mortality when both AKI and proteinuria or hematuria were considered together: the synergy indexes were 1.30 and 1.23 for proteinuria and hematuria, respectively.ConclusionsProteinuria and hematuria are associated with the risks of AKI and mortality in critically ill patients. Additionally, these findings had a synergistic effect with AKI on mortality.
    BMC Nephrology 06/2014; 15(1):93. DOI:10.1186/1471-2369-15-93 · 1.52 Impact Factor
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    ABSTRACT: Low or high counts of white blood cells (WBCs) and WBC subtypes can be a predictor of morbidity and mortality in several clinical settings. However, the correlations of WBC and its subtypes with acute kidney injury (AKI) and mortality remain unresolved in critically ill patients. The counts of WBC and subtypes, such as neutrophil, lymphocyte, monocyte, and eosinophil, were measured in 2,079 patients admitted to the intensive care unit (ICU) from June 2004 through June 2010. The non-linear relationship between WBC counts and AKI risk was initially explored by a restricted cubic spline analysis. The odds ratios (ORs) for AKI and 1-year mortality were calculated after adjustment for multiple covariates. The relationship between WBC counts and AKI risk was U-shaped. Accordingly, we divided patients into quintiles according to the counts of WBC or subtypes. The 1(st) and 5(th) quintiles of WBC counts had greater ORs for AKI (1.42 and 2.05, respectively) and mortality (1.40 and 1.36, respectively) compared with the 3(rd) quintile. After stratification by WBC subtype, the 5(th) quintile of neutrophil counts and the 1(st) quintiles of lymphocyte and monocyte counts tended to have higher ORs for AKI (1.69, 1.40, and 1.77, respectively). For mortality, the 1(st) quintiles of neutrophil, lymphocyte, and eosinophil counts were associated with higher mortality compared with the 3(rd) quintile (the ORs were 1.48, 1.57, and 1.42, respectively). Both leukopenia and leukocytosis are associated with AKI and mortality risk in critically ill patients. This result may be attributable to the change in the subtype counts.
    The Tohoku Journal of Experimental Medicine 03/2014; 232(3):177-85. DOI:10.1620/tjem.232.177 · 1.37 Impact Factor
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    ABSTRACT: The relationship between body fat mass and vitamin D appears to vary by ethnicity, but our understanding of this predisposition in Asians is limited due to the scarcity of prior investigations. Data on 1,697 Korean adults were obtained from the second and third years (2008-2009) of the fourth Korean National Health and Nutritional Examination Survey. Body fat mass was measured using dual-energy X-ray absorptiometry. Both linear regression analysis for serum 25-hydroxyvitamin D [25(OH)D] and logistic analysis for vitamin D deficiency [25(OH)D <20 ng/mL] were performed to determine significant predictors among BMI, waist circumference (WC), and body fat percentage (BF), after adjustment of multiple covariates. To explore a possible non-linear relationship between them, the fractional polynomials method was used. All analyses were conducted following stratification by sex. In linear regression analysis, BMI and WC were not associated with 25(OH)D. However, BF was inversely related to 25(OH)D, irrespective of the fat location (both appendicular and truncal fat) in both sexes. In logistic regression analysis, the highest quartile group of BF had a greater OR for vitamin D deficiency than the lower quartile groups, irrespective of the fat location and sex. However, the quartiles of BMI and WC were not associated with vitamin D deficiency. The linear relationships between BF and 25(OH)D (or vitamin D deficiency) were confirmed despite use of the fractional polynomials method. Body fat mass is inversely associated with serum 25(OH)D in Korean adults. Monitoring of vitamin D deficiency in Korean adults with high fat mass is needed.
    Asia Pacific Journal of Clinical Nutrition 01/2014; 23(1):65-75. · 1.36 Impact Factor
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    ABSTRACT: Background Periodontitis and chronic kidney disease (CKD) are important health issues; however, the association between periodontitis and CKD markers, especially in Korean adults, remains elusive. Methods Data on 15,729 Korean adults were obtained from the Korean National Health and Nutritional Examination Surveys IV and V. The CKD markers included a decreased estimated glomerular filtration rate (eGFR;<60 mL/min/1.73 m2), proteinuria, and hematuria. Odds ratios (ORs) and 95% confidence intervals were measured using stepwise multivariate logistic regression analyses for CKD markers based on the presence of periodontitis. Results Patients with periodontitis had greater unadjusted ORs for CKD markers compared to those without periodontitis, as follows: decreased eGFR, 4.07 (3.11–5.33); proteinuria, 2.12 (1.48–3.05); and hematuria, 1.25 (1.13–1.39; (all P<0.001). Periodontitis was a significant predictor of decreased eGFR independent of all covariates [1.39 (1.03–1.89), P=0.034]. However, the effect of periodontitis on decreased eGFR seemed to be affected by hypertension and diabetes mellitus. Periodontitis was not an independent predictor of proteinuria; the significance disappeared after adjusting for hypertension and diabetes mellitus. Periodontitis was significantly correlated with hematuria, leading to similar ORs regardless of the adjustment for covariates [1.29 (1.15–1.46), P<0.001]. Conclusion This study confirms the correlation between periodontitis and CKD markers, including decreased eGFR, proteinuria, and hematuria in Korean adults.
    12/2013; DOI:10.1016/j.krcp.2013.09.001
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    ABSTRACT: Anemia and vitamin D deficiency are both important health issues; however, the nature of the association between vitamin D and either hemoglobin or anemia remains unresolved in the general population. Data on 11,206 adults were obtained from the fifth Korean National Health and Nutritional Examination Survey. A generalized additive model was used to examine the threshold level for relationship between serum 25-hydroxyvitamin D [25(OH)D] and hemoglobin levels. A multivariate logistic regression for anemia was conducted according to 25(OH)D quintiles. All analyses were stratified according to sex and menstrual status. The generalized additive model confirmed a threshold 25(OH)D level of 26.4 ng/mL (male, 27.4 ng/mL; premenopausal females, 11.8 ng/mL; postmenopausal females, 13.4 ng/mL). The threshold level affected the pattern of association between 25(OH)D and anemia risk: the odds ratio of the 1(st) quintile but not the 2(nd), 3(rd), and 4(th) quintiles were significantly different from the 5(th) quintile in both premenopausal and postmenopausal females, however there was no obvious trend in males. This population-based study demonstrated a non-linear relationship with a threshold effect between serum 25(OH)D and hemoglobin levels in females. Further interventional studies are warranted to determine whether the appropriate level of hemoglobin can be achieved by the correction of vitamin D deficiency.
    PLoS ONE 08/2013; 8(8):e72605. DOI:10.1371/journal.pone.0072605 · 3.53 Impact Factor
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    ABSTRACT: The addition of relevant parameters to acute kidney injury (AKI) criteria might allow better prediction of patient mortality than AKI criteria alone. Here, we evaluated whether inclusion of AKI duration could address this issue. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines in 2,143 critically ill patients, within 15 days of patient admission. AKI cases were categorized according to tertiles of AKI duration: 1st tertile, 1--2 days; 2nd tertile, 3--5 days; and 3rd tertile, >=6 days. The hazard ratios (HRs) for overall survival rates in three groups were calculated after adjustment for multiple covariates compared with ICU patients without AKI as the reference group. The predictive ability for mortality was assessed by calculating the area under the curve (AUC) of the receiver operating characteristic curve. AKI increased the HRs for overall mortality, and the mortality rate increased with AKI duration: the adjusted HRs were 1.99 (1st tertile), 2.67 (2nd tertile), and 2.85 (3rd tertile) compared with the non-AKI group (all Ps < 0.001). The AUC of the ROC curve for overall mortality based on the AKI duration groups (0.716) was higher than the AUC of AKI staging using the KDIGO guidelines (0.696) (P = 0.001). When considering KDIGO stage and AKI duration together, the AUC (0.717) was also significantly higher than that using the KDIGO stage alone (P < 0.001). AKI duration is an additional parameter for the prediction of mortality in critically ill patients. The inclusion of AKI duration could be considered as a refinement of the AKI criteria.
    BMC Nephrology 06/2013; 14(1):133. DOI:10.1186/1471-2369-14-133 · 1.52 Impact Factor
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    ABSTRACT: INTRODUCTION: Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated. METHODS: Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008-2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables. RESULTS: Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019-1.777; P=0.037); 4th quartile, 1.52 (1.140-2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224-3.160; Ptrend=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses. DISCUSSION: The present study shows that high cadmium exposure is associated with a risk of hematuria.
    Environmental Research 05/2013; DOI:10.1016/j.envres.2013.04.001 · 3.24 Impact Factor
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    ABSTRACT: BACKGROUND: The effects of air pollution on the respiratory and cardiovascular systems, and the resulting impacts on public health, have been widely studied. However, little is known about the effect of air pollution on the occurrence of hemorrhagic fever with renal syndrome (HFRS), a rodent-borne infectious disease. In this study, we evaluated the correlation between air pollution and HFRS incidence from 2001 to 2010, and estimated the significance of the correlation under the effect of climate variables. METHODS: We obtained data regarding HFRS, particulate matter smaller than 10 mum (PM10) as an index of air pollution, and climate variables including temperature, humidity, and precipitation from the national database of South Korea. Poisson regression models were established to predict the number of HFRS cases using air pollution and climate variables with different time lags. We then compared the ability of the climate model and the combined climate and air pollution model to predict the occurrence of HFRS. RESULTS: The correlations between PM10 and HFRS were significant in univariate analyses, although the direction of the correlations changed according to the time lags. In multivariate analyses of adjusted climate variables, the effects of PM10 with time lags were different. However, PM10 without time lags was selected in the final model for predicting HFRS cases. The model that combined climate and PM10 data was a better predictor of HFRS cases than the model that used only climate data, for both the study period and the year 2011. CONCLUSIONS: This is the first report to document an association between HFRS and PM10 level.
    BMC Public Health 04/2013; 13(1):347. DOI:10.1186/1471-2458-13-347 · 2.32 Impact Factor
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    ABSTRACT: The purpose of our study was to evaluate the dietary intake of kidney transplant recipients (KTRs) and assess oral intake related nutrition problems. Fifty patients who had undergone kidney transplantation were included: 24 males, 26 females. The mean age was 46.8 ± 11.2 years, height was 161.3 ± 8.3 cm, and body weight was 60.5 ± 8.7 kg. We conducted nutrition education based on the diet guideline for KTRs (energy 32 kcal/kg of ideal body weight [IBW], protein 1.3 g/kg of IBW) and neutropenic diet guideline before discharge. Dietary intake of the patients at 1 month after transplantation was investigated by 3-day food records. Body weight and laboratory values for nutritional status and graft function were also collected. Body weight was significantly decreased from admission to discharge. Body weight from discharge to 1 month and 3 months after transplantation was increased but was not significant. Biochemical measurements were generally improved but the number of patients with hypophosphatemia increased. The daily dietary intake of energy and protein was adequate (33.1 kcal/kg, 1.5 g/kg, respectively). However, the dietary intake of calcium, folate, and vitamin C did not meet the Korean Recommended Nutrient Intake of vitamins and minerals (86.8%, 62.4%, and 88.0%, respectively). Patients with low intake of calcium, folate, and vitamin C presented low intake in milk and dairy products, vegetables, and fruits, and these foods were related to restricted food items in neutropenic diet. More attention should be paid on improving quality of diet, and reconsideration of present neutropenic diet guideline is necessary. These results can be used to establish evidence-based medical nutrition therapy guideline for KTRs.
    01/2013; 2(1):1-11. DOI:10.7762/cnr.2013.2.1.1
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    ABSTRACT: Kidney transplantation and accompanying medical conditions may result in changes in body composition. Such changes have been evaluated in Caucasian recipients, but not in Asian recipients. Herein, we conducted a study on Asian recipients because Asians have a different body composition from Caucasians. A total of 50 Asian recipients was enrolled as a prospective cohort. Using bioelectrical impedance analysis, body composition (muscle and fat mass) was assessed after 2 weeks (baseline), and at 1, 3, 6, 9, and 12 months following kidney transplantation. To find predictors related to changes, the data were analyzed by multivariate analysis using forward selection. All of the patients had good graft function during the study period. Patients gained approximately 3 kg within 1 yr of kidney transplantation. The proportion of muscle mass significantly decreased (P(trend) = 0.001) and the proportion of fat mass significantly increased over time (P(trend) = 0.002). The multivariate results revealed that male recipients, deceased donor type, and low protein intake were associated with an increase in fat mass and a decrease in muscle mass. The results from this study may help to investigate differences in body composition changes between races, as well as the factors related to these changes.
    Journal of Korean medical science 10/2012; 27(10):1182-7. DOI:10.3346/jkms.2012.27.10.1182 · 0.84 Impact Factor
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    ABSTRACT: Currently, the dosage of tacrolimus used after transplantation is based on the patient's body weight. However, there is a low correlation between body weight and body composition in kidney transplant recipients. In this study, we evaluate the pharmacokinetics of tacrolimus according to body composition in 18 Korean kidney transplant recipients with stable graft function.Methods Body composition parameters were calculated using bioelectrical impedance analysis. Pharmacokinetic profiles were determined 0, 1, 2, 3, and 4 hours after treatment with tacrolimus and were compared between high- and low-level median body composition groups. The values of C0, C1, C2, C3, and C4 were used in determining an abbreviated area under the curve (AUC) for tacrolimus.ResultsThe mean body mass index (BMI) and body composition values were as follows: BMI, 24.3 kg/m2; lean mass, 49.8 kg; and fat mass, 17.4 kg. There were no statistical differences in pharmacokinetic profiles between groups with different BMIs. However, the C0 and C4 in the high-fat group were significantly elevated compared with those of the low-fat group (P=0.024 and 0.031, respectively). Furthermore, the C0, C2, C3, and C4 and the AUC were significantly different between the two lean mass groups (P=0.007, 0.038, 0.047, 0.015, and 0.015, respectively). Other variables, such as waist circumference and arm muscle circumference, did not differentiate between the pharmacokinetic profiles of tacrolimus.Conclusion Taken together, these data suggest that tacrolimus dose monitoring based on body composition may provide adequate dosage leading to favorable long-term outcomes.
    09/2012; 31(3):157-162. DOI:10.1016/j.krcp.2012.06.007
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    ABSTRACT: Idiopathic focal segmental glomerulosclerosis (FSGS) occurring at young age is known to predispose to poor graft outcome, but the outcome of adulthood-onset FSGS (A-FSGS) has not been thoroughly investigated. Here, we compared the graft outcomes between kidney recipients with A-FSGS and childhood-onset FSGS (C-FSGS). We enrolled 47 A-FSGS recipients and 60 C-FSGS recipients with an onset age of ≤ 15, from four of the largest transplant centers in Korea. The baseline characteristics were similar between two groups. The 1- and 3-year cumulative recurrence rates were 20.0 and 22.1%, respectively. FSGS was recurrent in 19 C-FSGS patients [median duration, 2 months (interquartile range, IQR, 1-35)], and 11 patients had recurrent disease in A-FSGS [5 months (IQR, 3-37)]. The recurrence rate was similar between two groups (P = 0.126). The 5- and 10-year graft survival rates were 90.0 and 78.5%, respectively. The overall graft survival rates were not different between two groups. After adjusting baseline characteristics, the development of major outcomes was similar between two groups except acute rejection that was more frequent in A-FSGS. The age of disease onset did not affect recurrence in both groups. While grafts with recurrence had poorer graft survival in the A-FSGS group (P = 0.005), the recurrence was not associated with graft loss in the C-FSGS group (P = 0.558). The onset age did not affect the graft outcome in patients with FSGS, and the recurrence significantly affected graft survival in A-FSGS. Therefore, the main focus should aim for the management of recurrence.
    Nephrology Dialysis Transplantation 12/2011; 27(6):2559-65. DOI:10.1093/ndt/gfr699 · 3.37 Impact Factor
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    ABSTRACT: Diagnosis of acute kidney injury (AKI) has been a major concern due to its association with increased morbidity and mortality. However, the clinical implication of the urine output criterion (UOCr) in diagnosing AKI has not been fully established. We assessed the incidence of AKI among 1625 critically ill patients and analysed the overall survival rates based on the serum creatinine criterion (CrCr) and UOCr, both of which have been defined by the AKI Network (AKIN). Within 7 days of admission, the risk rate of AKI was 57.0% and the rate determined by UOCr alone was 25.7%. AKI determined by the UOCr alone increased hazard ratios (HRs) for mortality; 1.81 (Stage 1), 2.96 (Stage 2) and 4.17 (Stage 3) compared to non-AKI. However, the difference in mortality between Stages 2 and 3 using the CrCr alone was not significant (P = 0.881). In patients with Stages 2 and 3 by the CrCr, the UOCr further separated the survival rates (P = 0.001 among the four UOCr stages). The diuretic dose did not alter the discriminative function of the UOCr for survival rates. However, 42.1% of non-AKI cases, as determined by the UOCr, were identified as AKI cases by the CrCr. Although some AKI cases were not identified by the UOCr alone, the UOCr has an additional role in AKI staging, regardless of diuretic use.
    Nephrology Dialysis Transplantation 06/2011; 27(1):161-5. DOI:10.1093/ndt/gfr312 · 3.37 Impact Factor
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    ABSTRACT: There is a significant immune response to ischemia-reperfusion injury (IRI), but the role of immunomodulatory natural killer T (NKT) cell subtypes is not well understood. Here, we compared the severity of IRI in mice deficient in type I/II NKT cells (CD1d(-/-)) or type I NKT cells (Jα18(-/-)). The absence of NKT cells, especially type II NKT cells, accentuated the severity of renal injury, whereas repletion of NKT cells attenuated injury. Adoptively transferred NKT cells trafficked into the tubulointerstitium, which is the primary area of injury. Sulfatide-induced activation of type II NKT cells protected kidneys from IRI, but inhibition of NKT cell recruitment enhanced injury. In co-culture experiments, sulfatide-induced activation of NKT cells from either mice or humans attenuated apoptosis of renal tubular cells after transient hypoxia via hypoxia-inducible factor (HIF)-1α and IL-10 pathways. Renal tissue of patients with acute tubular necrosis (ATN) frequently contained NKT cells, and the number of these cells tended to negatively correlate with ATN severity. In summary, sulfatide-reactive type II NKT cells are renoprotective in IRI, suggesting that pharmacologic modulation of NKT cells may protect against ischemic injury.
    Journal of the American Society of Nephrology 06/2011; 22(7):1305-14. DOI:10.1681/ASN.2010080815 · 9.47 Impact Factor
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    ABSTRACT: Post-transplant outcome of kidney allografts depends on various factors, one of which may be the compatibility in volume between graft and recipient. However, previous studies adjusted the graft volume only for recipient's size. As the adjusted graft volume for donor's size would be substituted of nephron number more accurately, we adjusted the graft volume for both recipient's and donor's sizes. In 351 cases of living-donor kidney transplantation, we found that the adjusted graft volume for both recipient's and donor's body surface areas (BSAs) yielded larger area under the curves for the transplant outcomes than looking only at the adjusted volume for the recipient's BSA. The recipients were separated into two groups according to the low and high adjusted graft volumes. During the follow-up period (mean 55.6 months), the low-graft-volume group conferred greater risk of rejection, chronic change, glomerulonephritis, and graft loss than the high-graft-volume group (all p's < 0.05). However, the frequency of T-cell infiltration, as evaluated in protocol biopsy, was not different between the two adjusted graft volume groups. In conclusion, the graft volume as the surrogate marker for nephron number should be considered in kidney transplantation, especially in otherwise similar donor conditions.
    Clinical Transplantation 03/2011; 25(3):E327-35. DOI:10.1111/j.1399-0012.2011.01426.x · 1.49 Impact Factor

Publication Stats

125 Citations
58.00 Total Impact Points

Institutions

  • 2009–2015
    • Seoul National University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2010–2012
    • Seoul National University
      • • Department of Internal Medicine
      • • Law Research Institute
      Sŏul, Seoul, South Korea
  • 2009–2010
    • Seoul National University Bundang Hospital
      • Department of Nephrology
      Sŏul, Seoul, South Korea