Efficacy of Integrated Risk Score Using Omics-Based Biomarkers for the Prediction of Acute Rejection in Kidney Transplantation: A Randomized Prospective Pilot Study

Acute rejection (AR) is critical for long-term graft survival in kidney transplant recipients (KTRs). This study aimed to evaluate the efficacy of the integrated risk score of omics-based biomarkers in predicting AR in KTRs. This prospective, randomized, controlled, multicenter, pilot study enrolled 40 patients who recently underwent high-immunologic-risk kidney transplantation (KT). Five omics biomarkers were measured, namely, blood mRNA (three-gene signature), urinary exosomal miRNA (three-gene signature), urinary mRNA (six-gene signature), and two urinary exosomal proteins (hemopexin and tetraspanin-1) at 2 weeks and every 4 weeks after KT for 1 year. An integrated risk score was generated by summing each biomarker up. The biomarker group was informed about the integrated risk scores and used to adjust immunosuppression, but not the control group. The outcomes were graft function and frequency of graft biopsy. Sixteen patients in the biomarker group and nineteen in the control group completed the study. The mean estimated glomerular filtration rate after KT did not differ between the groups. Graft biopsy was performed in two patients (12.5%) and nine (47.4%) in the biomarker and control groups, respectively, with the proportion being significantly lower in the biomarker group (p = 0.027). One patient (6.3%) in the biomarker group and two (10.5%) in the control group were diagnosed with AR, and the AR incidence did not differ between the groups. The tacrolimus trough level was significantly lower in the biomarker group than in the control group at 1 year after KT (p = 0.006). Integrated omics biomarker monitoring may help prevent unnecessary or high-complication-risk biopsy and enables tailored immunosuppression by predicting the risk of AR in KTRs.

Anuria after kidney transplantation diagnosed as early recurrence of focal segmental glomerulosclerosis combined with acute calcineurin inhibitor nephrotoxicity: a case report and literature review

BACKGROUND

Primary focal segmental glomerulosclerosis (FSGS) is a glomerular disease that sometimes recurs in patients after kidney transplantation (KT) and increases the risk of graft loss. Proteinuria is a common early sign of recurrent FSGS, but an abrupt decrease in urine volume is rare. Herein, we report a patient with early recurrence of FSGS with anuria following KT.

CASE PRESENTATION

A 55-year-old man with end-stage kidney disease caused by primary FSGS experienced anuria on postoperative day 2 following deceased donor KT. Laboratory results revealed that serum tacrolimus trough levels were consistently elevated at the time of anuria. At first, we considered acute calcineurin inhibitor (CNI) nephrotoxicity based on graft biopsy on light microscopy, laboratory findings, and clinical courses. However, the allograft function did not recover even after discontinuation of CNI, and recurrent FSGS was diagnosed 2 weeks later on electron microscopy. A total of 13 sessions of plasmapheresis and two administrations of rituximab (375 mg/m2) were required to treat recurrent FSGS. The patient achieved a partial response, and the spot urine protein-to-creatinine ratio decreased from 15.5 g/g creatinine to 5.2 g/g creatinine. At 5 months following KT, the serum creatinine level was stable at 1.15 mg/dL.

CONCLUSIONS

These findings highlight that anuria can occur in cases of early recurrence of FSGS combined with acute CNI nephrotoxicity.

Dual Immunoglobulin Domain-Containing Cell Adhesion Molecule Increases Early in Renal Tubular Cell Injury and Plays Anti-Inflammatory Role

Dual immunoglobulin domain-containing cell adhesion molecule (DICAM) is a type I transmembrane protein that presents in various cells including renal tubular cells. This study evaluated the expression and protective role of DICAM in renal tubular cell injury. HK-2 cells were incubated and treated with lipopolysaccharide (LPS, 30 μg/mL) or hydrogen peroxide (H2O2, 100 μM) for 24 h. To investigate the effect of the gene silencing of DICAM, small interfering RNA of DICAM was used. Additionally, to explain its role in cellular response to injury, DICAM was overexpressed using an adenoviral vector. DICAM protein expression levels significantly increased following treatment with LPS or H2O2 in HK-2 cells. In response to oxidative stress, DICAM showed an earlier increase (2-4 h following treatment) than neutrophil gelatinase-associated lipocalin (NGAL) (24 h following treatment). DICAM gene silencing increased the protein expression of inflammation-related markers, including IL-1β, TNF-α, NOX4, integrin β1, and integrin β3, in H2O2-induced HK-2 cell injury. Likewise, in the LPS-induced HK-2 cell injury, DICAM knockdown led to a decrease in occludin levels and an increase in integrin β3, IL-1β, and IL-6 levels. Furthermore, DICAM overexpression followed by LPS-induced HK-2 cell injury resulted in an increase in occludin levels and a decrease in integrin β1, integrin β3, TNF-α, IL-1β, and IL-6 levels, suggesting an alleviating effect on inflammatory responses. DICAM was elevated in the early stage of regular tubular cell injury and may protect against renal tubular injury through its anti-inflammatory properties. DICAM has a potential as an early diagnostic marker and therapeutic target for renal cell injury.

Severe Acute Kidney Injury Associated with Transformation of Chronic Myelomonocytic Leukemia into Acute Myeloid Leukemia: A Case Report

Chronic myelomonocytic leukemia (CMML) is a rare hematologic disorder that infrequently causes acute kidney injury (AKI). CMML can transform into acute myeloid leukemia (AML), which can be accompanied by a deterioration in kidney function. However, severe AKI due to extramedullary manifestations of AML is rare. Herein, we present the case of a 67-year-old male patient with CMML that transformed into AML with severe AKI necessitating hemodialysis. The cause of the AKI was the AML transformation. The patient, with stable kidney function after chemotherapy for CMML, presented with a sudden decline in kidney function. Hemodialysis was initiated because of severe AKI, and histopathologic evaluation of the kidney biopsy specimen revealed severe, diffuse mixed inflammatory cell infiltrates in the interstitium and c-kit-immunopositive myeloblast-like cells. A bone marrow biopsy was performed because of the kidney biopsy findings suggesting that leukemic infiltration led to the diagnosis of AML. The patient received chemotherapy for AML, and his kidney function recovered. As illustrated in this case, severe AKI can develop as an early extramedullary manifestation during transformation from CMML to AML. Therefore, in patients with CMML and rapidly declining renal function, transformation into AML should be considered and histopathologically confirmed by kidney biopsy.

Factors Associated with Acute Kidney Injury Occurrence and Prognosis in Rhabdomyolysis at the Emergency Department

Background and Objectives: This study aimed to analyze patients with rhabdomyolysis who presented to emergency departments and identify their distribution of related disease and prognostic factors. Materials and Methods: A retrospective cohort study was conducted on patients with rhabdomyolysis who presented to emergency departments over a 10-year period. Patient data, including patients' demographic variables (sex and age), mode of arrival, final diagnosis, statin use, rhabdomyolysis trigger factors, and levels of serum creatine phosphokinase (CPK), myoglobin, creatinine, sodium, potassium, phosphate, calcium, and lactate, were analyzed. Univariate and multivariate logistic regression analyses were conducted to identify the predictive factors of acute kidney injury (AKI). Results: Among the patients, 268 (65.6%) were found to have trigger factors without underlying diseases. Furthermore, 115 (28.2%) patients developed AKI. This comprehensive study sheds light on the diverse factors influencing the occurrence of AKI in rhabdomyolysis and provides insights into AKI predictive markers. Furthermore, we analyzed the cases by dividing them into six groups: occurrence of AKI, occurrence of infection, and simple or complex rhabdomyolysis. CPK time course was found to be important in clinical prognosis, such as AKI occurrence, dialysis or not, and mortality. Conclusions: Age, statin use, elevated creatinine and lactate levels, and initial serum CPK level emerged as significant predictors of AKI. CPK time course was also found to be an important factor in predicting the clinical outcomes of patients with rhabdomyolysis.

Impact of Ring Finger Protein 20 and Its Downstream Regulation on Renal Tubular Injury in a Unilateral Nephrectomy Mouse Model Fed a High-Fat Diet

Abnormal lipid metabolism increases the relative risk of kidney disease in patients with a single kidney. Using transcriptome analysis, we investigated whether a high-fat diet leads to abnormalities in lipid metabolism and induces kidney cell-specific damage in unilateral nephrectomy mice. Mice with unilateral nephrectomy fed a high-fat diet for 12 weeks exhibited progressive renal dysfunction in proximal tubules, including lipid accumulation, vacuolization, and cell damage. Ring finger protein 20 (RNF20) is a ligase of nuclear receptor corepressor of peroxisome proliferator-activated receptors (PPARs). The transcriptome analysis revealed the involvement of RNF20-related transcriptome changes in PPAR signaling, lipid metabolism, and water transmembrane transporter under a high-fat diet and unilateral nephrectomy. In vitro treatment of proximal tubular cells with palmitic acid induced lipotoxicity by altering RNF20, PPARα, and ATP-binding cassette subfamily A member 1 (ABCA1) expression. PPARγ and aquaporin 2 (AQP2) expression decreased in collecting duct cells, regulating genetic changes in the water reabsorption process. In conclusion, a high-fat diet induces lipid accumulation under unilateral nephrectomy via altering RNF20-mediated regulation and causing functional damage to cells as a result of abnormal lipid metabolism, thereby leading to structural and functional kidney deterioration.

The impact of C-reactive protein-to-albumin ratio on mortality in patients with acute kidney injury requiring continuous renal replacement therapy: A multicenter retrospective study

INTRODUCTION

C-reactive protein-to-albumin ratio (CAR) is a prognostic marker in various diseases that represents patients' inflammation and nutritional status. Here, we aimed to investigate the prognostic value of CAR in critically ill patients with severe acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT).

METHODS

We retrospectively collected data from eight tertiary hospitals in Korea from 2006-2021. The patients were divided into quartiles according to CAR levels at the time of CRRT initiation. Cox regression analyses were performed to investigate the effect of CAR on in-hospital mortality. The mortality prediction performance of CAR was evaluated using the area under the curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

RESULTS

In total, 3995 patients who underwent CRRT were included, and the in-hospital mortality rate was 67.3% during the follow-up period. The 7-day, 30-day, and in-hospital mortality rates increased toward higher CAR quartiles (all P < 0.001). After adjusting for confounding variables, the higher quartile groups had an increased risk of in-hospital mortality (quartile 3: adjusted hazard ratio [aHR], 1.26, 95% confidence interval [CI], 1.10-1.43, P < 0.001; quartile 4: aHR, 1.22, 95% CI, 1.07-1.40, P = 0.003). CAR combined with APACHE II or SOFA scores significantly increased the predictive power compared to each severity score alone for the AUC, NRI, and IDI (all P < 0.05).

CONCLUSIONS

A high CAR is associated with increased in-hospital mortality in critically ill patients requiring CRRT. The combined use of CAR and severity scores provides better predictive performance for mortality than the severity score alone.

Effect of immunosuppressive agents on clinical outcomes in idiopathic membranous nephropathy

Background

Few comparative studies on the effects of immunosuppressants in patients with idiopathic membranous nephropathy have been conducted.

Methods

Data from 489 patients who received conservative treatment or immunosuppressants were retrospectively analyzed by propensity score matching. Primary outcomes were complete or partial remission (CR or PR) of proteinuria, and secondary outcomes were renal survival and infection.

Results

Of the 489 patients, 357 (73.0%) received immunosuppressants. Propensity score matching identified 82 patients from the conservative group and 82 patients in the immunosuppressant group. CR or PR at 12 months was significantly higher in the immunosuppressant group compared with the conservative group for the total population (p = 0.002) and the propensity score-matched population (p = 0.02). The use of immunosuppressants was significantly more effective with respect to achieving a CR or PR at 12 months in patients from the total population who were aged <65 years or female, or who had a proteinuria level of ≥4.0 g/g or an estimated glomerular filtration rate of ≥60 mL/min/1.73 m2 (p < 0.05). Renal survival was similar between patients receiving immunosuppressants and conservative treatment in both the total and matched populations. The immunosuppressant group (21.8%) had a significantly higher incidence of infections compared with the conservative group (13.6%) for the total population (p = 0.03), but statistical significance disappeared in the matched population (p > 0.99).

Conclusion

The remission rate was significantly higher in the immunosuppressant group than in the conservative group, particularly in the subgroup of patients who were young or female, or those with heavy proteinuria loads or good renal function.

The impact of severe depression on the survival of older patients with end-stage kidney disease

Background

Incidence of depression increases in patients with end-stage kidney disease (ESKD). We evaluated the association between depression and mortality among older patients with ESKD, which has not been studied previously.

Methods

This nationwide prospective cohort study included 487 patients with ESKD aged >65 years, who were categorized into minimal, mild-to-moderate, and severe depression groups based on their Beck Depression Inventory-II (BDI-II) scores. Predisposing factors for high BDI-II scores and the association between the scores and survival were analyzed.

Results

The severe depression group showed a higher modified Charlson comorbidity index value and lower serum albumin, phosphate, and uric acid levels than the other depression groups. The Kaplan-Meier curve revealed a significantly lower survival in the severe depression group than in the minimal and mild-to-moderate depression groups (p = 0.011). Multivariate Cox regression analysis confirmed that severe depression was an independent risk factor for mortality in the study cohort (hazard ratio, 1.39; 95% confidence interval, 1.01-1.91; p = 0.041). Additionally, BDI-II scores were associated with modified Charlson comorbidity index (p = 0.009) and serum albumin level (p = 0.004) in multivariate linear regression. Among the three depressive symptoms, higher somatic symptom scores were associated with increased mortality.

Conclusion

Severe depression among older patients with ESKD increases mortality compared with minimal or mild-to-moderate depression, and patients with concomitant somatic symptoms require careful management of their comorbidities and nutritional status.

Catastrophic rhabdomyolysis following breast reconstruction operation using an abdominal flap: a case report

Background

Rhabdomyolysis is a potentially fatal clinical syndrome resulting from the damage or breakdown of skeletal muscle, which can also lead to permanent disabilities. Based on our review of studies on rhabdomyolysis after prolonged surgeries, no other cases of rhabdomyolysis caused by muscle injury in the buttock area following breast reconstruction have been reported, making the current report the first to share information related to patient conditions and treatment progress in such cases.

Case Description

Here, we present the case of a 57-year-old Asian patient with left breast cancer. We performed immediate breast reconstruction using a deep inferior epigastric perforator (DIEP) flap anastomosed to the internal mammary vessels after a skin-sparing mastectomy with sentinel lymph node biopsy. The surgery exceeded the estimated time because, after anastomosis, severe congestion was observed in the flap and because of the need to perform re-anastomosis and the reconstruction of the internal mammary vein twice. The surgical team eventually re-performed the breast reconstruction using a contralateral pedicled transverse rectus abdominis myocutaneous (TRAM) flap. The patient underwent breast reconstruction in a sitting position to ensure a symmetrical and natural breast shape resembling its original state. Additionally, a brown splint was placed underneath both legs to keep the hip and knees flexed to ensure donor-site closure when using an abdominal-based flap. The patient was closely monitored in the early postoperative period. On postoperative day (POD) 3, patient developed hypotension and was deemed to have experienced a hypovolemic shock. A complete laboratory workup was performed, and a rhabdomyolysis diagnosis was made based on the laboratory results. We believe that rhabdomyolysis resulted from prolonged pressure on the large gluteus maximus muscle located below the site of the pressure sore in the present patient.

Conclusions

Postoperative rhabdomyolysis often results from prolonged surgery. Given the possibility of prolonged procedure time in patients undergoing breast reconstruction, the current case emphasizes the need to identify each patient's risk factors for rhabdomyolysis and prepare for possible rhabdomyolysis to prevent ischemic injuries and reduce the risk of complications such as hypovolemic shock.

Recurrent C3 Glomerulonephritis along with BK-Virus-Associated Nephropathy after Kidney Transplantation: A Case Report

C3 glomerulonephritis (C3GN) is a rare cause of end-stage kidney disease and frequently recurrent in allografts following kidney transplantation (KT). Herein, we describe the case of a kidney transplant recipient who developed recurrent C3GN along with BK-virus-associated nephropathy (BKVAN) following KT. A 33-year-old man diagnosed with membranoproliferative glomerulonephritis 17 years ago underwent preemptive KT with a donor kidney from his aunt. Proteinuria gradually increased after 3 months following KT, and graft biopsy was performed 30 months after KT. Histopathological examination revealed recurrent C3GN. The dosages of triple immunosuppressive maintenance therapy agents were increased. Subsequently, serum C3 levels recovered to normal levels. However, at 33 months following KT, the BK viral load increased and graft function gradually deteriorated; a second graft biopsy was performed at 46 months following KT, which revealed BKVAN and decreased C3GN activity. The dosages of immunosuppressive agents were decreased; subsequently, BKVAN improved and graft function was maintained with normal serum C3 levels at 49 months following KT. This case indicates that C3GN is highly prone to recurrence following KT and that immunosuppressive therapy for C3GN increases the risk of BKVAN.

Platelet-to-Lymphocyte Ratio and In-Hospital Mortality in Patients With AKI Receiving Continuous Kidney Replacement Therapy: A Retrospective Observational Cohort Study

Rationale & Objective

The platelet-to-lymphocyte ratio (PLR) is a marker of inflammation and a predictor of mortality in a variety of diseases. However, the effectiveness of PLR as a predictor of mortality in patients with severe acute kidney injury (AKI) is uncertain. We evaluated the association between the PLR and mortality in critically ill patients with severe AKI who underwent continuous kidney replacement therapy (CKRT).

Study Design

Retrospective cohort study.

Setting & Participants

A total of 1,044 patients who underwent CKRT in a single center, from February 2017 to March 2021.

Exposures

PLR.

Outcomes

In-hospital mortality.

Analytical Approach

The study patients were classified into quintiles according to the PLR values. A Cox proportional hazards model was used to investigate the association between PLR and mortality.

Results

The PLR value was associated with in-hospital mortality in a nonlinear manner, showing a higher mortality at both ends of the PLR. The Kaplan-Meier curve revealed the highest mortality with the first and fifth quintiles, whereas the lowest mortality occurred with the third quintile. Compared with the third quintile, the first (adjusted HR, 1.94; 95% CI, 1.44-2.62; P < 0.001) and fifth (adjusted HR, 1.60; 95% CI, 1.18-2.18; P = 0.002) quintiles of the PLR group had a significantly higher in-hospital mortality rate. The first and fifth quintiles showed a consistently increased risk of 30- and 90-day mortality rates compared with those of the third quintile. In the subgroup analysis, the lower and higher PLR values were predictors of in-hospital mortality in patients with older age, of female sex, and with hypertension, diabetes, and higher Sequential Organ Failure Assessment score.

Limitations

There may be bias owing to the single-center retrospective nature of this study. We only had PLR values at the time of initiation of CKRT.

Conclusions

Both the lower and higher PLR values were independent predictors of in-hospital mortality in critically ill patients with severe AKI who underwent CKRT.

Renal Sarcoidosis-like Reaction Induced by PD-1 Inhibitor Treatment in Non-Small Cell Lung Cancer: A Case Report and Literature Review

Monoclonal antibodies directed against immune checkpoint proteins have been widely used to treat various cancers and have resulted in favorable clinical outcomes. Despite these beneficial properties, immune checkpoint inhibitors (ICIs) can induce side effects called immune-related adverse events, including sarcoidosis-like reactions (SLR) across multiple organs. Here, we report a case of renal SLR after ICI treatment, and we review the related literature. A 66-year-old Korean patient with non-small cell lung cancer was referred to the nephrology clinic for renal failure after the 14th pembrolizumab treatment dose. A renal biopsy revealed multiple epithelioid cell granulomas, with several lymphoid aggregates in the renal interstitium and a moderate degree of inflammatory cell infiltration in the tubulointerstitium. A moderate dose of steroid therapy was initiated, and the serum creatinine level partially recovered after four weeks of treatment. Judicious monitoring of renal SLR is, therefore, required during ICI therapy, and a timely diagnosis by renal biopsy and appropriate treatment are important.

The effects of muscle mass and quality on mortality of patients with acute kidney injury requiring continuous renal replacement therapy

This study examined the effects of muscle mass on mortality in patients with acute kidney injury requiring continuous renal replacement therapy. It was conducted in eight medical centers between 2006 and 2021. The data of 2200 patients over the age of 18 years with acute kidney injury who required continuous renal replacement therapy were retrospectively collected. Skeletal muscle areas, categorized into normal and low attenuation muscle areas, were obtained from computed tomography images at the level of the third lumbar vertebra. Cox proportional hazards models were used to investigate the association between mortality within 1, 3, and 30 days and skeletal muscle index. Sixty percent of patients were male, and the 30-day mortality rate was 52%. Increased skeletal muscle areas/body mass index was associated with decreased mortality risk. We also identified a 26% decreased risk of low attenuation muscle area/body mass index on mortality. We established that muscle mass had protective effects on the mortality of patients with acute kidney injury requiring continuous renal replacement therapy. This study showed that muscle mass is a significant determinant of mortality, even if the density is low.

In vivo imaging of renal microvasculature in a murine ischemia-reperfusion injury model using optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) provides three-dimensional structural and semiquantitative imaging of microvasculature in vivo. We developed an OCTA imaging protocol for a murine kidney ischemia-reperfusion injury (IRI) model to investigate the correlation between renal microvascular changes and ischemic damage. Mice were divided into mild and moderate IRI groups according to the duration of ischemia (10 and 35 mins, respectively). Each animal was imaged at baseline; during ischemia; and at 1, 15, 30, 45, and 60 mins after ischemia. Amplitude decorrelation OCTA images were constructed with 1.5-, 3.0-, and 5.8-ms interscan times, to calculate the semiquantitative flow index in the superficial (50-70 μm) and the deep (220-340 μm) capillaries of the renal cortex. The mild IRI group showed no significant flow index change in both the superfial and the deep layers. The moderate IRI group showed a significantly decreased flow index from 15 and 45 mins in the superficial and deep layers, respectively. Seven weeks after IRI induction, the moderate IRI group showed lower kidney function and higher collagen deposition than the mild IRI group. OCTA imaging of the murine IRI model revealed changes in superficial blood flow after ischemic injury. A more pronounced decrease in superficial blood flow than in deep blood flow was associated with sustained dysfunction after IRI. Further investigation on post-IRI renal microvascular response using OCTA may improve our understanding of the relationship between the degree of ischemic insult and kidney function.

The benefit of planned dialysis to early survival on hemodialysis versus peritoneal dialysis: a nationwide prospective multicenter study in Korea

Optimal preparation is recommended for patients with advanced chronic kidney disease to minimize complications during dialysis initiation. This study evaluated the effects of planned dialysis initiation on survival in patients undergoing incident hemodialysis and peritoneal dialysis. Patients newly diagnosed with end-stage kidney disease who started dialysis were enrolled in a multicenter prospective cohort study in Korea. Planned dialysis was defined as dialysis therapy initiated with permanent access and maintenance of the initial dialysis modality. A total of 2892 patients were followed up for a mean duration of 71.9 ± 36.7 months and 1280 (44.3%) patients initiated planned dialysis. The planned dialysis group showed lower mortality than the unplanned dialysis group during the 1st and 2nd years after dialysis initiation (1st year: adjusted hazard ratio [aHR] 0.51; 95% confidence interval [CI] 0.37-0.72; P < 0.001; 2nd year: aHR 0.71; 95% CI 0.52-0.98, P = 0.037). However, 2 years after dialysis initiation, mortality did not differ between the groups. Planned dialysis showed a better early survival rate in hemodialysis patients, but not in peritoneal dialysis patients. Particularly, infection-related mortality was reduced only in patients undergoing hemodialysis with planned dialysis initiation. Planned dialysis has survival benefits over unplanned dialysis in the first 2 years after dialysis initiation, especially in patients undergoing hemodialysis. It improved infection-related mortality during the early dialysis period.

Dynamic nature and prognostic value of the neutrophil-to-lymphocyte ratio in critically ill patients with acute kidney injury on continuous renal replacement therapy: A multicenter cohort study

Introduction

Patients with acute kidney injury (AKI) receiving renal replacement therapy constitute the subgroup of AKI with the highest risk of mortality. Despite recent promising findings on the neutrophil-to-lymphocyte ratio (NLR) in AKI, studies have not yet addressed the clinical implication of the NLR in this population. Therefore, we aimed to examine the prognostic value of NLR in critically ill patients requiring continuous renal replacement therapy (CRRT), especially focusing on temporal changes in NLR.

Methods

We enrolled 1,494 patients with AKI who received CRRT in five university hospitals in Korea between 2006 and 2021. NLR fold changes were calculated as the NLR on each day divided by the NLR value on the first day. We performed a multivariable Cox proportional hazard analysis to assess the association between the NLR fold change and 30-day mortality.

Results

The NLR on day 1 did not differ between survivors and non-survivors; however, the NLR fold change on day 5 was significantly different. The highest quartile of NLR fold change during the first 5 days after CRRT initiation showed a significantly increased risk of death (hazard ratio [HR], 1.65; 95% confidence intervals (CI), 1.27–2.15) compared to the lowest quartile. NLR fold change as a continuous variable was an independent predictor of 30-day mortality (HR, 1.14; 95% CI, 1.05–1.23).

Conclusion

In this study, we demonstrated an independent association between changes in NLR and mortality during the initial phase of CRRT in AKI patients receiving CRRT. Our findings provide evidence for the predictive role of changes in the NLR in this high-risk subgroup of AKI.

Pretransplant C-reactive protein-to-albumin ratio predicts mortality in kidney transplant recipients: a retrospective cohort study

Background

The C-reactive protein (CRP)-to-albumin ratio (CAR) is a more effective prognostic indicator than CRP or albumin alone in various diseases. This study aimed to evaluate the predictive value of the CAR for mortality in kidney transplant recipients (KTRs).

Methods

A total of 924 patients who underwent their first kidney transplantation at Kyungpook National University Hospital during 2006-2020 were enrolled and classified into quartile (Q) groups according to their pretransplant CAR values. A Cox regression analysis was conducted to analyze the hazard ratios (HRs) of mortality.

Results

Fifty-nine patients died during the posttransplant period (mean, 85.2±44.2 months). All-cause mortality (Q1, 3.0%; Q2, 4.8%; Q3, 7.8%; Q4, 10.0%; P for trend <0.001) and infection-related mortality increased linearly with an increase in CAR (P for trend=0.004). The Q3 and Q4 had higher risks of all-cause mortality than Q1 after adjusting for confounding factors (Q3 adjusted HR [aHR] 2.49, 95% confidence interval [CI] 1.04-5.99, P=0.041; Q4 aHR 3.09, 95% CI 1.31-7.27, P=0.010). Q4 was also independently associated with infection-related mortality (aHR 5.83, 95% CI 1.27-26.8, P=0.023). The area under the curve of the CAR for all-cause and infection-related mortality was higher than that of CRP or albumin alone. There was no association between CAR and death-censored graft failure or acute rejection.

Conclusions

A higher pretransplant CAR increases the risk of posttransplant mortality, particularly infection-related, in KTRs. Pretransplant CAR can be an effective and easily accessible predictor of posttransplant mortality.

Effect of pretransplant dialysis vintage on clinical outcomes in deceased donor kidney transplant

The waiting time for deceased donor kidney transplants (DDKT) is increasing. We evaluated DDKT prognosis according to the pretransplant dialysis vintage. A total of 4117 first-time kidney transplant recipients were enrolled from a prospective nationwide cohort in Korea. DDKT recipients were divided into tertiles according to pretransplant dialysis duration. Graft failure, mortality, and composite were compared between DDKT and living donor kidney transplant (LDKT) recipients. Pretransplant dialysis vintage was longer annually in DDKT recipients. In the subdistribution of the hazard model for the competing risk, the first tertile did not show an increased risk of graft failure compared with LDKT recipients; however, the second and third tertile groups had an increased risk of graft failure compared to LDKT recipients (adjusted hazard ratio [aHR] 3.59; 95% confidence interval [CI] 1.69-7.63; P < 0.001; aHR 2.37; 95% CI 1.06-5.33; P = 0.037). All DDKT groups showed a significantly higher risk of patient death than LDKT, with the highest risk in the third tertile group (aHR 11.12; 95% CI 4.94-25.00; P < 0.001). A longer pretransplant dialysis period was associated with a higher risk of the composite of patient death and graft failure in DDKT recipients. DDKT after a short period of dialysis had non-inferior results on graft survival compared with LDKT.

Factors Affecting Selection of a Dialysis Modality in Elderly Patients With Chronic Kidney Disease: A Prospective Cohort Study in Korea

Background

We investigated factors associated with the selection of a dialysis modality for elderly patients compared to younger patients.

Methods

This study included 2,514 incident dialysis patients from a Korean multicenter prospective cohort. Multivariate logistic regression analyses were performed with demographic, socioeconomic, and clinical data to analyze factors associated with the chosen dialysis modality. Differences in these factors were compared between the elderly (≥65 years) and younger (<65 years) patients.

Results

Of the enrolled patients, 1,746 (69.5%) and 768 (30.6%) selected hemodialysis (HD) and peritoneal dialysis (PD), respectively. The percentage of PD was higher in younger patients than in elderly patients (37.1 vs. 16.9%, p < 0.001). Multivariate analysis showed that planned dialysis (p < 0.001), employment status (p < 0.001), and independent economic status (p = 0.048) were independent factors for selecting PD, whereas peripheral vascular disease (p = 0.038) and tumor (p = 0.010) were factors for selecting HD in the younger group. In the elderly group, planned dialysis (p < 0.001) and congestive heart failure (CHF; p = 0.002) were associated with choosing PD; however, tumor (p = 0.006) was associated with choosing HD. A two-way ANOVA showed that planned dialysis and CHF showed a significant interaction effect with age on modality selection.

Conclusions

As the age of patients with chronic kidney disease increased, HD was more frequently selected compared to PD. Dialysis planning and CHF interacted with age in selecting dialysis modalities in elderly patients. Elderly patients were less affected by socioeconomic status than younger patients.

Treatment of rituximab in patients with idiopathic membranous nephropathy: a case series and literature review

BACKGROUND/AIMS

Membranous nephropathy (MN) is a major cause of nephrotic syndrome in adults. This study aimed to evaluate the effect of rituximab (RTX) in patients with idiopathic MN (iMN) who have a high risk of progression.

METHODS

We retrospectively analyzed data of 13 patients with iMN, who received RTX treatments from January 2014 to July 2020. RTX was indicated in patients with iMN with severe proteinuria and decreasing estimated glomerular filtration rate (eGFR) in the previous 6 months despite other immunosuppressive therapies.

RESULTS

The patients were predominantly males (n = 11) and with a mean age of 55.3 years; median eGFR, 37.0 mL/min/1.73 m2 (interquartile range [IQR], 26.3 to 66.5); serum albumin level, 2.6 g/dL (IQR, 1.9 to 3.1); and spot urine protein-to-creatinine ratio at baseline, 6.6 g/g (IQR, 5.7 to 12.9). In a median follow-up of 22 months, eight patients (61.5%) achieved complete or partial remission. In responder group (n = 8), median eGFR increased from 31.5 to 61.5 mL/min/1.73 m2 (p = 0.049) and serum albumin level increased from 2.3 to 4.2 g/dL (p = 0.017) from RTX initiation to last follow-up. Antiphospholipase A2 receptor antibody (anti-PLA2R-Ab) was positive in six among seven tested patients, which markedly decreased in the responder group. There were no adverse events after RTX.

CONCLUSION

This study suggests that RTX is a safe and effective treatment option for patients with iMN who have a high risk of progression. Individualized therapy based on anti-PLA2R-Ab titer would be needed for better outcomes.

Omics-based biomarkers for diagnosis and prediction of kidney allograft rejection

Kidney transplantation is the preferred treatment for patients with end-stage kidney disease, because it prolongs survival and improves quality of life. Allograft biopsy is the gold standard for diagnosing allograft rejection. However, it is invasive and reactive, and continuous monitoring is unrealistic. Various biomarkers for diagnosing allograft rejection have been developed over the last two decades based on omics technologies to overcome these limitations. Omics technologies are based on a holistic view of the molecules that constitute an individual. They include genomics, transcriptomics, proteomics, and metabolomics. The omics approach has dramatically accelerated biomarker discovery and enhanced our understanding of multifactorial biological processes in the field of transplantation. However, clinical application of omics-based biomarkers is limited by several issues. First, no large-scale prospective randomized controlled trial has been conducted to compare omics-based biomarkers with traditional biomarkers for rejection. Second, given the variety and complexity of injuries that a kidney allograft may experience, it is likely that no single omics approach will suffice to predict rejection or outcome. Therefore, integrated methods using multiomics technologies are needed. Herein, we introduce omics technologies and review the latest literature on omics biomarkers predictive of allograft rejection in kidney transplant recipients.

Elderly kidney transplant recipients have favorable outcomes but increased infection-related mortality

Background

The number of elderly patients with end-stage kidney disease has been increasing, but the outcomes of kidney transplants (KT) remain poorly understood in elderly patients. Therefore, we evaluated the clinical outcomes of elderly KT recipients and analyzed the impact of elderly donors.

Methods

This retrospective cohort study included patients who underwent KT between 2000 and 2019. KT recipients were divided into four groups according to a combination of recipient and donor age (≥60 or <60 years); elderly recipients: old-to-old (n = 46) and young-to-old (n = 83); young recipients: old-to-young (n = 98) and young-to-young (n = 796). We compared the risks of mortality, graft failure, and acute rejection between groups using Cox regression analysis.

Results

The incidence of delayed graft function, graft failure, and acute rejection was not different among groups. Annual mean tacrolimus trough level was not lower in elderly recipients than young recipients during 10-year follow-up. Mortality was significantly higher in elderly recipients (p = 0.001), particularly infection-related mortality (p < 0.001). In multivariable Cox regression analysis, old-to-old and young-to-old groups had increased risk of mortality (adjusted hazard ratio [aHR], 2.89; 95% confidence interval [CI], 1.14–7.32; p = 0.03; aHR, 3.06; 95% CI, 1.51–6.20; p = 0.002). However, graft failure and acute rejection risks were not increased in elderly recipients.

Conclusion

In elderly recipients, graft survival and acute rejection-free survival were not inferior to those of young recipients. However, mortality, especially risk of infection-related death, was increased in elderly recipients. Thus, low immunosuppression intensity might help decrease mortality in elderly recipients.

Superiority of Simplified Acute Physiologic Score II Compared with Acute Physiologic and Chronic Health Evaluation II and Sequential Organ Failure Assessment Scores for Predicting 48-Hour Mortality in Patients Receiving Continuous Kidney Replacement Therapy

BACKGROUND

Predicting early mortality is important in patients undergoing continuous kidney replacement therapy (CKRT), especially in the first 48 h. This study aimed to determine the predictive performance of the Simplified Acute Physiologic Score (SAPS) II, the Acute Physiologic and Chronic Health Evaluation (APACHE) II, and the Sequential Organ Failure Assessment (SOFA) scores for early mortality in patients receiving CKRT.

METHODS

Data from patients with acute kidney injury receiving CKRT were consecutively and retrospectively obtained at a tertiary medical center between August 2017 and March 2021. The outcomes included 48-h and 7-day mortality. The scoring systems were evaluated via discrimination at the time of CKRT initiation (using area under the receiver operating characteristics curve [AUROC]) and calibration (via Hosmer-Lemeshow goodness-of-fit C statistics).

RESULTS

Among eligible 652 patients, 95 (14.6%) and 212 (32.5%) died within 48 h and within 7 days, respectively. The AUROC for SAPS II (0.71, 95% confidence interval [CI]: 0.65-0.77, p = 0.016 vs. APACHE II score, p = 0.044 vs. SOFA score) was significantly higher than that of the APACHE II (0.66, 95% CI: 0.60-0.72) and SOFA scores (0.66, 95% CI: 0.60-0.72) for 48-h mortality. However, no significant differences in the AUROCs for SAPS II, APACHE II, and SOFA scores for 7-day mortality were observed. The calibration of the SAPS II for 48-h and 7-day mortality was adequate (p = 0.507 and p = 0.141, respectively).

CONCLUSIONS

The predictive performance of SAPS II for mortality within the first 48 h was superior to that of the APACHE II and SOFA scores in patients with acute kidney injury receiving CKRT.

Multiplex Immunofluorescence Assay of Infiltrating Mononu-Clear Cell Subsets in Acute T-Cell-Mediated Rejection and BK Virus-Associated Nephropathy in the Allograft Kidney

Renal allograft biopsy is the gold standard procedure for diagnosis of kidney rejection via specific pathological changes. To provide a better assessment of immunologic events in acute T-cell-mediated rejection (acute TCMR) and BK virus-associated nephropathy (BKVAN) cases, we used multiplex immunofluorescence staining to identify infiltrating mononuclear cell subsets in the cortex area of transplanted kidneys. Antibodies to CD4, CD8, CD20, CD68, Foxp3, and cytokeratin were used. In cortical interstitium, CD8+ cells were significantly more prevalent in acute TCMR than BKVAN cases (34% vs. 22.8%, p = 0.034). In medulla, CD20+ cells were significantly more prevalent in BKVAN than acute TCMR cases (51.9% vs. 11.3%, p = 0.028).

Higher Serum Total Cholesterol to High-Density Lipoprotein Cholesterol Ratio Is Associated with Increased Mortality among Incident Peritoneal Dialysis Patients

This study evaluated the association of the serum total cholesterol to high-density lipoprotein cholesterol ratio (TC/HDL-C) with mortality in incident peritoneal dialysis (PD) patients. We performed a multi-center, prospective cohort study of 630 incident PD patients from 2008 to 2015 in Korea. Participants were stratified into quintiles according to baseline TC, HDL-C, LDL-C and TC/HDL-C. The association between mortality and each lipid profile was evaluated using multivariate Cox regression analysis. During a median follow-up period of 70.3 ± 25.2 months, 185 deaths were recorded. The highest TC/HDL-C group had the highest body mass index, percentage of diabetes and serum albumin level. Multivariate analysis demonstrated that the highest quintile of TC/HDL-C was associated with increased risk of all-cause mortality (hazard ratio 1.69, 95% confidence interval 1.04-2.76; p = 0.036), whereas TC, HDL-C and LDL-C were not associated with mortality. Linear regression analysis showed a positive correlation between TC/HDL-C and body mass index. Increased serum TC/HDL-C was an independent risk factor for mortality in the subgroup of old age, female, cardiovascular disease and low HDL-C. The single lipid marker of TC or HDL-C was not able to predict mortality in PD patients. However, increased serum TC/HDL-C was independently associated with all-cause mortality in PD patients.

Declining trend of preemptive kidney transplantation and impact of pretransplant dialysis: a Korean nationwide prospective cohort study

We evaluated the temporal trend of preemptive kidney transplantation (KT) and the effect of pretransplant dialysis duration on post-transplant outcomes. This was a nationwide cohort study of the first-time 3392 living donor KT (LDKT) recipients (2014-2019). The annual changes in proportion of preemptive KT, factors associated with preemptive KT, and post-transplant outcomes were analyzed. Preemptive KT was performed in 816 (24.1%) patients. Annual trend analysis revealed gradual decrease in preemptive KT over time (P = 0.042). Among the underlying causes of preemptive KT, the proportion of diabetes increased and that of glomerulonephritis decreased during the study period. Glomerulonephritis as the primary renal disease was a predictor of preemptive KT. Patients with pretransplant dialysis >6 months showed increased graft failure risk than preemptive KT in the subdistribution of hazard model for competing risk (adjusted hazard ratio [aHR], 2.53; 95% confidence interval [CI], 1.09-5.87; P = 0.031) and in propensity score-matched analysis (aHR, 2.45; 95% CI, 1.02-5.92; P = 0.034); however, pretransplant dialysis ≤6 months showed comparable graft survival with preemptive KT in both analyses. Preemptive KT declined over successive years, associated with an increase in diabetes and a decrease in glomerulonephritis as underlying causes of KT. Short period of dialysis less than 6 months does not affect graft survival compared with preemptive KT; however, longer dialysis decreases graft survival.

Outcomes of Remote Patient Monitoring for Automated Peritoneal Dialysis: A Randomized Controlled Trial

INTRODUCTION

We hypothesize that remote patient monitoring (RPM) for automated peritoneal dialysis (APD) and feedback could enhance patient self-management and improve outcomes. The aim of this study was to evaluate the efficacy of RPM-APD compared to traditional APD (T-APD) without RPM.

METHODS

In this multicenter, randomized controlled trial, patients on APD were randomized to T-APD (n = 29) or RPM-APD (n = 28) at 12 weeks and followed until 25 weeks. Health-related quality of life (HRQOL), patient and medical staff satisfaction with RPM-APD, and dialysis-related outcomes were compared between the 2 groups.

RESULTS

We found no significant differences in HRQOL scores at the time of enrollment and randomization between RPM-APD and T-APD. At the end of the study, the RPM-APD group showed better HRQOL for the sleep domain (p = 0.049) than the T-APD group and the T-APD group showed better HRQOL for the sexual function domain (p = 0.030) than the RPM-APD group. However, we found no significant interactions between the time and groups in terms of HRQOL. Different HRQOL domains significantly improved over time in patients undergoing RPM-APD (effects of kidney disease, p = 0.025) and T-APD (burden of kidney disease, p = 0.029; physical component summary, p = 0.048). Though medical staff satisfaction with RPM-APD was neutral, most patients were quite satisfied with RPM-APD (median score 82; possible total score 105 on 21 5-item scales) and the rating scores were maintained during the study period. We found no significant differences in dialysis adherence, accuracy, adequacy, overhydration status, blood pressure, or the number of unplanned visits between the 2 groups.

DISCUSSION/CONCLUSION

Although HRQOL and dialysis-related outcomes were comparable between RPM-APD and T-APD, RPM-APD was positive in terms of patient satisfaction. Further long-term and large-scale studies will be required to determine the efficacy of RPM-APD.

TRIAL REGISTRATION

CRIS identifier: KCT0003390, registered on December 14, 2018 - retrospectively registered, https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=12348.

Paricalcitol Improves Hypoxia-Induced and TGF-β1-Induced Injury in Kidney Pericytes

Recently, the role of kidney pericytes in kidney fibrosis has been investigated. This study aims to evaluate the effect of paricalcitol on hypoxia-induced and TGF-β1-induced injury in kidney pericytes. The primary cultured pericytes were pretreated with paricalcitol (20 ng/mL) for 90 min before inducing injury, and then they were exposed to TGF-β1 (5 ng/mL) or hypoxia (1% O₂ and 5% CO₂). TGF-β1 increased α-SMA and other fibrosis markers but reduced PDGFRβ expression in pericytes, whereas paricalcitol reversed the changes. Paricalcitol inhibited the TGF-β1-induced cell migration of pericytes. Hypoxia increased TGF-β1, α-SMA and other fibrosis markers but reduced PDGFRβ expression in pericyte, whereas paricalcitol reversed them. Hypoxia activated the HIF-1α and downstream molecules including prolyl hydroxylase 3 and glucose transporter-1, whereas paricalcitol attenuated the activation of the HIF-1α-dependent molecules and TGF-β1/Smad signaling pathways in hypoxic pericytes. The gene silencing of HIF-1α vanished the hypoxia-induced TGF-β1, α-SMA upregulation, and PDGFRβ downregulation. The effect of paricalcitol on the HIF-1α-dependent changes of fibrosis markers was not significant after the gene silencing of HIF-1α. In addition, hypoxia aggravated the oxidative stress in pericytes, whereas paricalcitol reversed the oxidative stress by increasing the antioxidant enzymes in an HIF-1α-independent manner. In conclusion, paricalcitol improved the phenotype changes of pericyte to myofibroblast in TGF-β1-stimulated pericytes. In addition, paricalcitol improved the expression of fibrosis markers in hypoxia-exposed pericytes both in an HIF-1α-dependent and independent manner.

GDF-15 Predicts In-Hospital Mortality of Critically Ill Patients with Acute Kidney Injury Requiring Continuous Renal Replacement Therapy: A Multicenter Prospective Study

Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine. This study evaluated the association between GDF-15 and in-hospital mortality among patients with severe acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). Among the multicenter prospective CRRT cohort between 2017 and 2019, 66 patients whose blood sample was available were analyzed. Patients were divided into three groups according to the GDF-15 concentrations. The median GDF-15 level was 7865.5 pg/mL (496.9 pg/mL in the healthy control patients). Baseline characteristics were not different among tertile groups except the severity scores and serum lactate level, which were higher in the third tertile. After adjusting for confounding factors, the patients with higher GDF-15 had significantly increased risk of mortality (second tertile: adjusted hazards ratio [aHR], 3.67; 95% confidence interval [CI], 1.05-12.76; p = 0.041; third tertile: aHR, 6.81; 95% CI, 1.98-23.44; p = 0.002). Furthermore, GDF-15 predicted in-hospital mortality (area under the curve, 0.710; 95% CI, 0.585-0.815) better than APACHE II and SOFA scores. Serum GDF-15 concentration was elevated in AKI patients requiring CRRT, higher in more severe patients. GDF-15 is a better independent predictor for in-hospital mortality of critically ill AKI patients than the traditional risk scoring system such as APACHE II and SOFA scores.

Early critical cortical infarction by anti-angiotensin II type 1 receptor antibody: A case report and literature review

RATIONALE

Anti-angiotensin II type 1 receptor antibodies (AT1R-Abs) have been demonstrated to increase the risk of antibody-mediated rejection. We report a case of AT1R-Ab mediated rejection which caused early critical cortical infarction.

PATIENT CONCERNS

A 52-year-old man with end-stage kidney disease underwent preemptive kidney transplantation (KT) from his wife. He had no immunologic risk except ABO incompatibility. Proper desensitization treatment were applied prior to KT. On postoperative day 1, he showed stable clinical course with adequate urine output, but there was no decrease in serum creatinine level and imaging studies showed hypoperfusion in the transplanted kidney.

DIAGNOSES

Allograft biopsy revealed total cortical infarction with severe necrotizing vasculitis, but the medullary area was preserved. Serum AT1R-Ab concentration was elevated from 10.9 U/mL before KT to 19.1 U/mL on 7 days after KT.

INTERVENTIONS

He was treated with plasmapheresis, intravenous immunoglobulin, rituximab, high-dose methylprednisolone, and bortezomib.

OUTCOMES

The treatment showed a partial response, and he was discharged with 7.3 mg/dL creatinine level. At 4 months, his creatinine plateaued at 5.5 mg/dL and AT1R-Ab decreased to 3.6 U/mL.

LESSONS

This case highlights the risk of early active antibody-mediated rejection by preformed AT1R-Ab, suggesting its ability to exhibit atypical histopathologic findings, such as total cortical infarction.

Histopathologic and clinicopathologic classifications of antineutrophil cytoplasmic antibody-associated glomerulonephritis: a validation study in a Korean cohort

Background

Antineutrophil cytoplasmic antibodies (ANCA)-associated glomerulonephritis (AAGN) is a common cause of rapidly progressive glomerulonephritis and requires prompt and proper immunosuppressive therapy to improve renal prognosis. This study aimed to evaluate the predictive value of two different classifications for renal outcomes in Korean AAGN patients.

Methods

Ninety-two patients who were diagnosed with AAGN at two tertiary hospitals between 2004 and 2018 were retrospectively analyzed retrospectively. The histopathologic classification according to glomerular pathology and the clinicopathologic classification according to normal glomeruli ratio, degree of interstitial fibrosis/tubular atrophy, and baseline renal function were evaluated using the Cox proportional hazards model.

Results

Forty-five patients (48.9%) progressed to end-stage kidney disease (ESKD) during the observation period. The mean age was 61.0 ± 15.3 years, and most patients had myeloperoxidase-ANCA (93.5%). In the histopathologic classification, the best renal survival occurred in the focal class, whereas the sclerotic class had the worst renal survival (sclerotic class vs. focal class; adjusted hazard ratio [aHR], 5.05; 95% confidence interval [CI], 1.32–19.31; p = 0.018). The mixed class had intermediate renal outcomes (mixed class vs. focal class; aHR, 4.23; 95% CI, 1.23–14.58; p = 0.022). In the clinicopathologic classification, the high-risk group had poor renal outcomes compared with the low-risk group (aHR, 6.56; 95% CI, 1.25–34.26; p = 0.026), but renal outcomes did not differ between the low- and medium-risk groups.

Conclusion

In Korean AAGN patients, histopathologic and clinicopathologic classifications had predictive value for renal outcomes, especially in the sclerotic class or the high-risk group with higher risk of progression to ESKD despite treatment.

Hypertension and Electrolyte Disorders in Patients with COVID-19

The worldwide coronavirus disease 2019 (COVID-19) pandemic is still in progress, but much remains unknown about the disease. In this article, we review the association of hypertension or the renin-angiotensin system (RAS) with COVID-19 and the correlation between electrolyte disorders and disease severity. Underlying hypertension is likely to be associated with severe or critical COVID-19, but the relationship is not clear owing to confounding factors. Angiotensin-converting enzyme 2 (ACE2) plays an important role in the non-classical RAS pathway and binds to a receptor binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The RAS blockade is known to increase ACE2 levels, but controversy remains regarding the effect of RAS blockade therapy in the course of COVID-19. Some reports have indicated a protective effect of RAS blockade on COVID-19, whereas others have reported an association of RAS blockade therapy with the occurrence of severe complications such as acute kidney injury and admission to the intensive care unit. Electrolyte disorders are not uncommon in patients with COVID-19, and severe COVID-19 has frequently shown hypokalemia, hyponatremia, and hypocalcemia. Electrolyte imbalances are caused by alteration of RAS, gastrointestinal loss, effects of proinflammatory cytokines, and renal tubular dysfunction by the invasion of SARS-CoV-2.

Renoprotective Effects of Alpha-1 Antitrypsin against Tacrolimus-Induced Renal Injury

The protective effects of alpha-1 antitrypsin (AAT) in tacrolimus (TAC)-induced renal injury was evaluated in a rat model. The TAC group rats were subcutaneously injected with 2 mg/kg TAC every day for four weeks. The TAC with AAT group was cotreated with daily subcutaneous injections of TAC and intraperitoneal injections of AAT (80 mg/kg) for four weeks. The effects of AAT on TAC-induced renal injury were evaluated using serum biochemistry, histopathology, and Western blotting. The TAC injection significantly increased renal interstitial fibrosis, inflammation, and apoptosis as compared to the control treatment. The histopathological examination showed that cotreatment of TAC and AAT attenuated interstitial fibrosis (collagen, fibronectin, and α-SMA staining), and α-SMA expression in Western blotting was also decreased. Immunohistochemical staining for inflammation (osteopontin and ED-1 staining) revealed improved interstitial inflammation in the TAC with AAT group compared to that in the TAC group. The TAC treatment increased renal apoptosis compared to the control treatment, based on the results of increased immunohistochemical staining of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), increased caspase-3 activity, and lower Bcl-2 to Bad expression ratio. However, AAT cotreatment significantly changed these markers and consequently showed decreased apoptosis. AAT protects against TAC-induced renal injury via antifibrotic, anti-inflammatory, and antiapoptotic effects.

Idiopathic membranous nephropathy in older patients: Clinical features and outcomes

Background

Various factors can affect renal and patient outcome in idiopathic membranous nephropathy (iMN). We aimed to identify predictors of renal and patient survival in patients with iMN, with a special focus on outcomes among older patients.

Methods

We retrieved data on 1,776 patients (mean age 53.0 ± 14.7 years; 1,075 [60.5%] males) diagnosed with iMN from the Korean GlomeruloNEphritis sTudy (KoGNET), a database compiled from 18 centers in Korea.

Results

The cohort included 428 (24.1%) patients over 65 years old. Compared to younger patients, this group had lower hemoglobin and serum albumin levels, a higher incidence of nephrotic-range proteinuria, and higher prevalences of hypertension and diabetes. At last follow-up, complete or partial remission rates were not significantly different between the older and younger groups. Older age (HR: 0.98, 95%CI: 0.97–0.99), elevated hemoglobin (HR: 0.82, 95%CI: 0.72–0.93), high serum albumin (HR: 0.66, 95%CI: 0.44–0.99), and a high estimated glomerular filtration rate (HR: 0.96, 95%CI: 0.95–0.97) at biopsy were good predictors of renal outcomes. Significant risk factors for patient survival were older age (HR: 1.04, 95%CI: 1.01–1.10) and hypertension at biopsy (HR: 2.76, 95%CI: 1.30–5.90).

Conclusions

Older patients with iMN had favorable renal outcomes, but poor patient survival, compared to younger patients. Prognostic information on outcomes in this study might be helpful for optimizing the management of patients with iMN.

Medium cut-off dialyzer improves erythropoiesis stimulating agent resistance in a hepcidin-independent manner in maintenance hemodialysis patients: results from a randomized controlled trial

The response to erythropoiesis stimulating agents (ESAs) is affected by inflammation linked to middle molecules in hemodialysis (HD) patients. We evaluated the effect of a medium cut-off (MCO) dialyzer on ESA resistance in maintenance HD patients. Forty-nine patients who underwent high-flux HD were randomly allocated to the MCO or high-flux group. The primary outcome was the changes of erythropoietin resistance index (ERI; U/kg/wk/g/dL) between baseline and 12 weeks. The MCO group showed significant decrease in the ESA dose, weight-adjusted ESA dose, and ERI compared to the high-flux group at 12 weeks (p < 0.05). The generalized estimating equation models revealed significant interactions between groups and time for the ESA dose, weight-adjusted ESA dose, and ERI (p < 0.05). Serum iron and transferrin saturation were higher in the MCO group at 12 weeks (p < 0.05). The MCO group showed a greater reduction in TNF-α and lower serum TNF-α level at 12 weeks compared to the high-flux group (p < 0.05), whereas no differences were found in the reduction ratio of hepcidin and serum levels of erythropoietin, erythroferrone, soluble transferrin receptor and hepcidin between groups. HD with MCO dialyzer improves ESA resistance over time compared to high-flux HD in maintenance HD patients. The MCO dialyzer provides superior removal of the inflammatory cytokine and thus improves iron metabolism in a hepcidin-independent manner.

Novel histopathologic predictors for renal outcomes in crescentic glomerulonephritis

Introduction

Crescentic glomerulonephritis (CrGN) is a histologic feature of severe glomerular injury, clinically characterized by a rapid decline of renal function when not treated in a timely fashion. Factors associated with CrGN prognosis have not been thoroughly investigated. This study investigated the prognostic predictors of renal outcomes associated with CrGN, such as the histopathologic classification of anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, arteriosclerosis, and tertiary lymphoid organ (TLO) formation.

Methods

A total of 114 patients diagnosed with CrGN between 2010 and 2018 at two university-based hospitals has been retrospectively analyzed. Relationships between potential predictors and renal outcomes were analyzed using Cox proportional hazards model and linear regression analysis.

Results

The mean age was 61.0 ± 15.3 years, and 49.1% were male. Among them, 92 (80.7%) and 11 (9.6%) patients were positive for ANCA and for anti-glomerular basement membrane antibody, respectively. During the median follow-up of 458.0 days, 55 patients (48.2%) had advanced to end-stage renal disease (ESRD). Cox proportional hazards analysis revealed that patients under the mixed and sclerotic classes had worse renal survival compared to those in the focal class (mixed: hazard ratio [HR], 3.74; 95% confidence interval [CI], 1.18 to 11.82; P = 0.025; sclerotic: HR, 4.84; 95% CI, 1.44 to 16.32; P = 0.011). Severe arteriosclerosis was also associated with poor renal survival (HR, 2.44; 95% CI, 1.04 to 5.77; P = 0.042). TLOs were observed in 41 patients (36.0%). Moreover, TLO formation was also a prognostic factor for ESRD (HR, 1.82; 95% CI, 1.03 to 3.21; P = 0.040). In the multivariate linear regression analysis, age and sclerotic class were independent predictors for the change in estimated glomerular filtration rate during 1 year after biopsy.

Conclusions

Specific histopathologic findings, histopathologic classification, severity of arteriosclerosis, and TLO formation provide helpful information in predicting renal outcomes associated with CrGN.

Impact of Donor-Recipient Age Difference on Graft Function and Survival After Deceased Donor Kidney Transplantation

BACKGROUND

Donor-recipient age difference (DRAD) is one of the reasons why patients on kidney waiting lists refuse to receive the offered organ. However, its impact on deceased donor kidney transplantation (DDKT) outcomes is still controversial.

METHODS

One hundred fifty-three kidney transplant recipients (KTRs) who received their first-time DDKT were enrolled. The KTRs were divided into groups by DRAD: group 1 (n = 74) (DRAD < 0) and group 2 (n = 79) (DRAD ≥ 0). The KTRs in group 2 were divided into 3 subgroups: DRAD 0 to 10 (n = 35), 10 to 20 (n = 32), and ≥ 20 (n = 12). The outcome measures included estimated glomerular filtration rate (eGFR), delayed graft function (DGF), acute rejection (AR), and graft and patient survival.

RESULTS

There were no significant differences in clinical outcomes between group 1 and 2 except eGFR until 5 years after DDKT. Among the subgroups of group 2, DGF, AR, patient survival, and eGFR until 5 years showed no significant differences. However, graft survival was significantly different (P = .015); in addition, in the DRAD ≥ 20 subgroup, graft survival decreased compared with that in the DRAD 10 to 20 subgroup and DRAD 0 to 10 subgroup (P = .020, P = .012, respectively). In a multivariate Cox proportional hazards analysis, the DRAD ≥ 20 subgroup showed a higher risk for graft failure than the DRAD 0 to 10 subgroup.

CONCLUSIONS

Although donors were of the same age or older than recipients, DDKT showed acceptable graft outcomes. However, because donors over 20 years older than recipients showed a decreased graft survival, it might be important to consider this point in donor-recipient matching of DDKT.

Natural soluble human leukocyte antigen class I in donor serum neutralizes donor-specific HLA alloantibodies in recipient serum

Background

Human leukocyte antigen (HLA) molecules are cell-bound but can be identified in a soluble form. These soluble HLA (sHLA) molecules have an immunomodulatory function. We investigated whether natural sHLA in donor serum can neutralize donor-specific HLA alloantibodies (DSAs) in recipient serum.

Methods

Neutralizing effects of donor serum on DSAs in recipient serum were measured using inhibition assay principle of flow cytometric crossmatch (FCXM), performed using sera from 143 kidney transplant recipients and their donors. The adding of donor serum to recipient serum yielded lower mean fluorescence intensity (MFI) ratios (test/control) than when diluent was added [Roswell Park Memorial Institute (RPMI) or third-party serum], which was presumed to be caused by the neutralizing effects of sHLA.

Results

In the recipient group with class I DSAs alone (N=14), donor serum addition to recipient serum resulted in lower T cell MFI ratios [2.25 (1.31‒32.51)] than those observed on RPMI addition [3.04 (1.33‒125.39), P<0.05]. In the recipient group with class II DSAs alone (N=27), donor serum addition showed no significant difference in B cell MFI ratios [5.03 (1.41‒103.53)] compared to diluent addition: RPMI [4.50 (1.34‒145.98)] or third-party serum [5.08 (1.44‒138.47)], P>0.05 for both.

Conclusion

Using inhibition FCXM, we verified that natural sHLA class I in donor serum neutralizes DSAs in recipient serum. However, no neutralizing effects of sHLA class II were revealed in this study. These potentially beneficial effects of sHLA infused via blood-derived products should be considered when desensitizing highly HLA-sensitized patients.

Outcomes of COVID-19 among Patients on In-Center Hemodialysis: An Experience from the Epicenter in South Korea

Patients with advanced chronic kidney disease (CKD) or who are on hemodialysis (HD) could have increased susceptibility to the 2019 coronavirus disease (COVID-19) given their pre-existing comorbidities, older age, compromised immune system, and regular visits to populated outpatient dialysis centers. This study included 14 consecutive patients on HD or with advanced CKD who initiated HD after being diagnosed with laboratory-confirmed COVID-19 from February to April 2020 in hospitals throughout Daegu, South Korea. The included patients, 42.9% of whom were men, had a mean age of 63.5 years. Four patients had a history of contact with a patient suffering from COVID-19. The most common symptom was cough (50.0%), followed by dyspnea (35.7%). The mean time from symptom onset to diagnosis and admission was 2.6 and 3.5 days, respectively. Patients exhibited lymphopenia and elevated inflammatory markers, including C-reactive protein and ferritin. Chest radiography findings showed pulmonary infiltration in 10 patients. All patients underwent regular HD in a negative pressure room and received antiviral agents. Four patients received mechanical ventilation and continuous renal replacement therapy at a median duration of 14.0 and 8.5 days, respectively. One patient underwent extracorporeal membrane oxygenation for three days. Among the 14 patients included, two died due to acute respiratory distress syndrome, nine were discharged from the hospital, and three remained hospitalized. Despite the high-risk conditions associated with worse outcomes, patients on HD did not exhibit extremely poor overall COVID-19 outcomes perhaps due to early diagnosis, prompt hospitalization, and antiviral therapy.

P1798MYCOPHENOLIC ACID TROUGH CONCENTRATION AND DOSE ARE ASSOCIATED WITH HEMATOLOGIC ABNORMALITIES BUT NOT REJECTION IN KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Little is known regarding the safe fixed dose of mycophenolic acid (MPA) for preventing biopsy-proven acute rejection (BPAR) in kidney transplant recipients (KTRs). We investigated the correlation of MPA trough concentration (MPA C0) and dose with renal transplant outcomes and adverse events.

Method

This study included 79 consecutive KTRs who received MPA with tacrolimus (TAC) and corticosteroids. The MPA C0 of all the enrolled KTRs was measured, which was determined monthly by using particle-enhanced turbidimetric inhibition immunoassay for 12 months, and clinical data were collected at each time point. The clinical endpoints included BPAR, any cytopenia, and BK or cytomegalovirus infections.

Results

No differences in MPA C0 and dose were observed between KTRs with or without BPAR or viral infections under statistically comparable TAC concentrations. MPA C0 was significantly higher in patients with leukopenia (P = 0.021) and anemia (P = 0.002) compared with those without cytopenia. The MPA dose was significantly higher in patients with thrombocytopenia (P = 0.002) compared with those without thrombocytopenia. MPA C0 ≥ 3.5 µg/mL was an independent risk factor for leukopenia (adjusted odds ratio [AOR] 3.80, 95% confidence interval [CI] 1.24–11.64, P = 0.019) and anemia (AOR 5.90, 95% CI 1.27–27.51, P = 0.024). An MPA dose greater than the mean value of 1188.8 mg/day was an independent risk factor for thrombocytopenia (AOR 3.83, 95% CI 1.15–12.78, P = 0.029). However, an MPA dose less than the mean value of 1137.3 mg/day did not increase the risk of BPAR.

Conclusion

Either a higher MPA C0 or dose was associated with an increased risk of cytopenia, but neither a lower MPA C0 nor dose was associated with BPAR within the first year of transplantation. Hence, a reduced MPA dose with TAC and corticosteroids might be safe in terms of reducing hematologic abnormalities without causing rejection.

P0411PREDICTORS OF RENAL AND PATIENT OUTCOME IN PATIENTS WITH IDIOPATHIC MEMBRANOUS NEPHROPATHY: FROM KOGNET DATA

Background and Aims

Idiopathic membranous nephropathy (iMN) is a leading cause of nephrotic syndrome and one of the major causes of end-stage renal disease (ESRD). Various factors can affect renal and patient outcome in patients with iMN. In this study, we analyzed the predictors of renal and patient survival in patients with iMN.

Method

We analyzed 1,776 patients diagnosed with iMN in Korean GlomeruloNEphritis STudy (KoGNET), a retrospective database of patients with renal biopsy from 1979 to 2018 from 18 centers in Korea. Student t-test for continuous variables and Chi-square test for categorical variables were performed for analyses. Cox proportional hazard regression was used to determine risk factors affecting renal and patient survival.

Results

The mean age of patients was 53.0 ± 14.7 years old and 1,075 (60.5%) were male. At the time of renal biopsy, 755 (46.0%) and 266 (16.2%) had hypertension and diabetes, respectively. Serum albumin level was 2.7 ± 0.8 g/dL and 871 (49.0%) had nephrotic range of proteinuria. When analyzed by dividing over 65 and under, the hemoglobin and serum albumin level were lower, more patients showed nephrotic ranged proteinuria, and higher prevalence of comorbidities such as hypertension, diabetes, coronary heart disease and cerebrovascular disease in the group over 65 than in the group under 65. Median duration of follow-up was 88.0 (38.0 – 115.1) months. Complete or partial remission rates were 48.5%, 63.8%, and 68.0% at 6 months, 12months after biopsy, and last follow-up, respectively. In Cox proportional hazard regression, high hemoglobin [HR 0.66 (0.47 – 0.93), p=0.017], high serum albumin level [HR 0.41 (0.18 – 0.94), p=0.034], and high estimated GFR by CKD-EPI equation [HR 0.94 (0.91 – 0.96), p&lt;0.001] at biopsy were good predictors for renal outcome, whereas presence of cerebrovascular disease at biopsy [HR 6.45 (1.16 – 35.71), p=0.033] were poor prognostic factors for ESRD. Age 65 and older [HR 3.26 (1.53 – 6.95), p=0.002] and presence of hypertension at biopsy [HR 2.45 (1.09 – 5.54), p=0.031] were significant risk factors for patient survival in multivariate Cox proportional regression analysis.

Conclusion

High hemoglobin and serum albumin, and good renal function at biopsy were good predictors for renal survival. Older age and hypertension at biopsy were poor prognostic factors for patient survival in iMN patients. Prognostic information of outcomes in this study might be helpful to optimize management in iMN patients.

Randomized controlled trial of medium cut-off versus high-flux dialyzers on quality of life outcomes in maintenance hemodialysis patients

Medium cut-off (MCO) dialyzers help remove larger middle molecules associated with symptoms related to the accumulation of uremic retention solutes. We investigated the effect of an MCO dialyzer on the improvement of quality of life (QOL) in maintenance hemodialysis (HD) patients. Forty-nine HD patients with high-flux dialysis were randomly assigned to either an MCO (Theranova 400, Baxter) or a high-flux (FX CorDiax 80 or 60, Fresenius Medical Care) dialyzer and completed the study. QOL was assessed at baseline and after 12 weeks of treatment using the Kidney Disease Quality of Life Short Form-36, and pruritus was assessed using a questionnaire and visual analog scale. The reduction ratios of middle molecules were also evaluated. Laboratory markers, including serum albumin, did not differ between the two groups after 12 weeks. Removals of kappa and lambda free light chains were greater for MCO dialyzer than high-flux dialyzer. The MCO group had higher scores than the high-flux group in the domains of physical functioning and physical role (75.2 ± 20.8 vs. 59.8 ± 30.1, P = 0.042; 61.5 ± 37.6 vs. 39.0 ± 39.6, P = 0.047, respectively), and the MCO group had lower mean scores for morning pruritus distribution and the frequency of scratching during sleep (1.29 ± 0.46 vs. 1.64 ± 0.64, P = 0.034; 0.25 ± 0.53 vs. 1.00 ± 1.47, P = 0.023, respectively). MCO dialyzers may improve patient-reported outcomes, particularly the physical components of QOL and uremic pruritus, in patients with high-flux dialyzers.

Patterns in renal diseases diagnosed by kidney biopsy: A single-center experience

Background

The worldwide incidence of renal disease diagnosed by a kidney biopsy varies with age, race, sex, and region. Owing to a lack of studies and limited research resources for this disease in Korea, we investigated renal disease patterns by analyzing data from kidney biopsies performed over 13 years in a university-based teaching hospital in Korea.

Methods

Among 2,053 kidney biopsies performed from 2001 to 2013 at Kyungpook National University Hospital, 1,924 were retrospectively analyzed for histopathologic, demographic, and clinical data as well as laboratory results.

Results

Among the 1,924 studied kidney biopsies, 1,078 were males (56.0%) and the mean age was 37.7 ± 16.5 years. Asymptomatic urinary abnormalities were the most common clinical manifestation (62.5%). Immunoglobulin A nephropathy (IgAN) was the most common primary glomerular disease (37.4%), followed by minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulonephritis and crescentic glomerulonephritis. Secondary glomerular diseases accounted for 10.3% of the total biopsies, with lupus nephritis being the most common (4.6%) followed by Henoch-Schönlein purpura nephritis and diabetic nephropathy. The most common cause of nephrotic syndrome was MCD (42.1%) followed by MN. Among patients seropositive for hepatitis B or C, IgAN (28.3% and 21.4%, respectively) was the most common cause.

Conclusion

IgAN and lupus nephritis were the most common primary and secondary glomerular diseases, respectively. Race, region, and practice patterns may affect renal disease patterns in different cohorts.

Computer simulations of X-ray phase-contrast images and microtomographic observation of tubules in dentin

An investigation of the problems of X-ray imaging of dentinal tubules is presented. Two main points are addressed. In the first part of this paper, the problem of computer simulating tubule images recorded in a coherent synchrotron radiation (SR) beam has been discussed. A phantom material which involved a two-dimensional lattice of the tubules with parameters similar to those of dentin was considered. By a comparative examination of two approximations, it was found that the method of phase-contrast imaging is valid if the number of tubules along the beam is less than 100. Calculated images from a lattice of 50 × 50 tubules are periodic in free space but depend strongly on the distance between the specimen and the detector. In the second part, SR microtomographic experiments with millimetre-sized dentin samples in a partially coherent beam have been described. Tomograms were reconstructed from experimental projections using a technique for incoherent radiation. The main result of this part is the three-dimensional rendering of the directions of the tubules in a volume of the samples. Generation of the directions is possible because a tomogram shows the positions of the tubules. However, a detailed tubule cross-section structure cannot be restored.