Medium cut-off dialyzer improves reduction ratios of large middle molecules associated with vascular calcification

Background

We aimed to investigate the change in the large middle molecule (>15 kDa) removal rate, which is associated with vascular calcification, when using a medium cut-off (MCO) dialyzer compared to a high-flux (HF) dialyzer.

Methods

Twenty patients with clinically stable maintenance hemodialysis were investigated over a 15-week study period. Dialyzer efficacies were evaluated during the last midweek hemodialysis treatment for each consecutive dialyzer membrane use: 1st HF, MCO, and 2nd HF dialyzer; 5 weeks each period. Changes in α1-microglobulin (33 kDa) during a dialysis session were analyzed to assess the efficacy of the MCO dialyzer as a reference. The levels and reduction ratios of fibroblast growth factor 23 (FGF23, 32 kDa), osteoprotegerin (OPG, 60 kDa), and sclerostin (22 kDa) were analyzed. Large middle molecules were measured using an enzyme-linked immunosorbent assay.

Results

Serum hemoglobin, phosphorus, and corrected calcium levels were not significantly different for each dialyzer period. Total protein and albumin values during the MCO dialyzer period did not decrease compared with the HF dialyzer period. The reduction ratio of α1-microglobulin was significantly higher in the MCO dialyzer than in the HF dialyzer (p < 0.001). The reduction ratios of FGF23 (p < 0.001), OPG (p < 0.001), and sclerostin (p < 0.001) were significantly higher in the MCO dialyzer than those in the HF dialyzer.

Conclusion

The reduction rate of large middle molecules related to vascular calcification, such as FGF23, OPG, and sclerostin, was significantly higher when using the MCO dialyzer than the HF dialyzer.

Incomplete distal renal tubular acidosis uncovered during pregnancy: A case report

BACKGROUND

Renal tubular acidosis (RTA) is a renal cause of non-anion-gap metabolic acidosis characterized by low urinary ammonia excretion. This condition has a low prevalence, and various congenital and acquired etiologies. To date, only a few cases of idiopathic RTA uncovered during pregnancy have been reported.

CASE SUMMARY

A previously healthy 32-year-old Korean woman at 30 wk of gestation was admitted to Pusan National University Hospital with preterm labor. At admission, the patient presented with hypokalemia, non-anion-gap metabolic acidosis, and nephrocalcinosis. Distal RTA was diagnosed based on laboratory blood and urine findings and imaging examinations. Various tests, including next-generation gene sequencing panels for nephropathy, were performed to determine the etiology of the disease, which indicated that it was idiopathic. The patient received sodium bicarbonate and potassium chloride supplementation. After 3 wk, she delivered a baby who was subsequently diagnosed with corpus callosum agenesis and colpocephaly. During regular follow-ups for 6 mo postpartum, her hypokalemia and metabolic acidosis were gradually resolved, and medications eventually discontinued.

CONCLUSION

Herein we describe a case of idiopathic distal RTA discovered during pregnancy. Hypokalemia and metabolic acidosis resolved spontaneously after delivery.

Serum and urine metabolomic biomarkers for predicting prognosis in patients with immunoglobulin A nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most prevalent form of glomerulonephritis worldwide. Prediction of disease progression in IgAN can help to provide individualized treatment based on accurate risk stratification.

METHODS

We performed proton nuclear magnetic resonance-based metabolomics analyses of serum and urine samples from healthy controls, non-progressor (NP), and progressor (P) groups to identify metabolic profiles of IgAN disease progression. Metabolites that were significantly different between the NP and P groups were selected for pathway analysis. Subsequently, we analyzed multivariate area under the receiver operating characteristic (ROC) curves to evaluate the predictive power of metabolites associated with IgAN progression.

RESULTS

We observed several distinct metabolic fingerprints of the P group involving the following metabolic pathways: glycolipid metabolism; valine, leucine, and isoleucine biosynthesis; aminoacyl-transfer RNA biosynthesis; glycine, serine, and threonine metabolism; and glyoxylate and dicarboxylate metabolism. In multivariate ROC analyses, the combinations of serum glycerol, threonine, and proteinuria (area under the curve [AUC], 0.923; 95% confidence interval [CI], 0.667-1.000) and of urinary leucine, valine, and proteinuria (AUC, 0.912; 95% CI, 0.667-1.000) showed the highest discriminatory ability to predict IgAN disease progression.

CONCLUSION

This study identified serum and urine metabolites profiles that can aid in the identification of progressive IgAN and proposed perturbed metabolic pathways associated with the identified metabolites.

Predicting outcomes of continuous renal replacement therapy using body composition monitoring: a deep-learning approach

Fluid balance is a critical prognostic factor for patients with severe acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). This study evaluated whether repeated fluid balance monitoring could improve prognosis in this clinical population. This was a multicenter retrospective study that included 784 patients (mean age, 67.8 years; males, 66.4%) with severe AKI requiring CRRT during 2017-2019 who were treated in eight tertiary hospitals in Korea. Sequential changes in total body water were compared between patients who died (event group) and those who survived (control group) using mixed-effects linear regression analyses. The performance of various machine learning methods, including recurrent neural networks, was compared to that of existing prognostic clinical scores. After adjusting for confounding factors, a marginal benefit of fluid balance was identified for the control group compared to that for the event group (p = 0.074). The deep-learning model using a recurrent neural network with an autoencoder and including fluid balance monitoring provided the best differentiation between the groups (area under the curve, 0.793) compared to 0.604 and 0.606 for SOFA and APACHE II scores, respectively. Our prognostic, deep-learning model underlines the importance of fluid balance monitoring for prognosis assessment among patients receiving CRRT.

Effect of fluid overload on survival in patients with sepsis-induced acute kidney injury receiving continuous renal replacement therapy

The association between fluid overload and survival has not been well elucidated in critically ill patients with sepsis-induced acute kidney injury (SIAKI) receiving continuous renal replacement therapy (CRRT). We investigated the optimal cutoff value of fluid overload for predicting mortality and whether minimizing fluid overload through CRRT is associated with a survival benefit in these patients. We examined 543 patients with SIAKI who received CRRT in our intensive care unit. The degree of cumulative fluid overload in relation to body weight was expressed as the percentage fluid overload (%FO). %FO was further subdivided into %FO from AKI diagnosis to CRRT initiation (%FOpreCRRT) and total fluid overload (%FOtotal). The best cutoff value of fluid overload for predicting the 28-day mortality was %FOpreCRRT > 4.6% and %FOtotal > 9.6%. Multivariable analysis demonstrated that patients with %FOpreCRRT > 4.6% and %FOtotal > 9.6% were 1.9 times and 3.37 times more likely to die than those with %FOpreCRRT ≤ 4.6% and %FOtotal ≤ 9.6%. The 28-day mortality was the highest in patients with %FOpreCRRT > 4.6% and %FOtotal > 9.6% (84.7%), followed by those with %FOpreCRRT ≤ 4.6% and %FOtotal > 9.6% (65.0%), %FOpreCRRT > 4.6% and %FOtotal ≤ 9.6% (43.6%), and %FOpreCRRT ≤ 4.6% and %FOtotal ≤ 9.6% (22%). This study demonstrated that fluid overload was independently associated with the 28-day mortality in critically ill patients with SIAKI. Future prospective studies are needed to determine whether minimizing fluid overload using CRRT improves the survival of these patients.

Rapid decline in kidney function is associated with rapid deterioration of health-related quality of life in chronic kidney disease

This study aimed to evaluate changes in health-related quality of life (HRQOL) in patients with chronic kidney disease (CKD) according to decline in kidney function. HRQOL was assessed using the Short Form-36 questionnaire composed of a physical component summary (PCS) and mental component summary (MCS). Rapid decline in kidney function was defined as a decline in the estimated glomerular filtration rate (eGFR) of > 3 mL/min/1.73 m²/year. Rapid deterioration of HRQOL was defined a change in the HRQOL value greater than the median. Among 970 patients, 360 (37.1%) were in the rapid kidney function decline group. In 720 patients who were 1:1 propensity score-matched, the baseline eGFR was not significantly different between the non-rapid and rapid kidney function decline groups. Compared with the baseline PCS score, the 5-year PCS score decreased in the non-rapid and rapid kidney function decline groups. The 5-year MCS score significantly decreased in the rapid kidney function decline group alone. Rapid decline in kidney function was significantly associated with rapid deterioration of the PCS (odds ratio [OR]: 1.48; 95% confidence interval [CI]: 1.07-2.05; P = 0.018) and MCS (OR: 1.89; 95% CI 1.36-2.62; P < 0.001) scores. Rapid decline in kidney function was associated with rapid deterioration of HRQOL in patients with CKD.

Hospital mortality and prognostic factors in critically ill patients with acute kidney injury and cancer undergoing continuous renal replacement therapy

BACKGROUND

Whether continuous renal replacement therapy (CRRT) should be applied to critically ill patients with both acute kidney injury (AKI) and cancer remains controversial because of poor expected outcomes. The present study determined prognostic factors for all-cause in-hospital mortality in patients with AKI and cancer undergoing CRRT.

METHODS

We included 471 patients with AKI and cancer who underwent CRRT at the intensive care unit of a Korean tertiary hospital from 2013 to 2020, and classified them by malignancy type. The primary outcomes were 28-day all-cause mortality rate and prognostic factors for in-hospital mortality. The secondary outcome was renal replacement therapy (RRT) dependency at hospital discharge.

RESULTS

The 28-day mortality rates were 58.8% and 82% in the solid and hematologic malignancy groups, respectively. Body mass index (BMI), presence of oliguria, Sequential Organ Failure Assessment (SOFA) score, and albumin level were common predictors of 28-day mortality in the solid and hematologic malignancy groups. A high heart rate and the presence of severe acidosis were prognostic factors only in the solid malignancy group. Among the survivors, the proportion with RRT dependency was 25.0% and 33.3% in the solid and hematologic malignancy groups, respectively.

CONCLUSION

The 28-day mortality rate of cancer patients with AKI undergoing CRRT was high in both the solid and hematologic malignancy groups. BMI, presence of oliguria, SOFA score, and albumin level were common predictors of 28-day mortality in the solid and hematologic malignancy groups, but a high heart rate and severe acidosis were prognostic factors only in the solid malignancy group.

Maintenance of the critical care system during the pandemic in non-COVID-19 patients requiring continuous renal replacement therapy: a single center experience

Background

During the COVID-19 pandemic, maintenance of essential healthcare systems became very challenging. We describe the triage system of our institute, and assess the quality of care provided to critically ill non-COVID-19 patients requiring continuous renal replacement therapy (CRRT) during the pandemic.

Methods

We introduced an emergency triage pathway early in the pandemic. We retrospectively reviewed the medical records of patients who received CRRT in our hospital from January 2016 to March 2021. We excluded end-stage kidney disease patients on maintenance dialysis. Patients were stratified as medical and surgical patients. The time from hospital arrival to intensive care unit (ICU) admission, the time from hospital arrival to intervention/operation, and the in-hospital mortality rate were compared before (January 2016 to December 2019) and during (January 2021 to March 2021) the pandemic.

Results

The mean number of critically ill patients who received CRRT annually in the surgical department significantly decreased during the pandemic in (2016–2019: 76.5 ± 3.1; 2020: 56; p < 0.010). Age, sex, and the severity of disease at admission did not change, whereas the proportions of medical patients with diabetes (before: 44.4%; after: 56.5; p < 0.005) and cancer (before: 19.4%; after: 32.3%; p < 0.001) increased during the pandemic. The time from hospital arrival to ICU admission and the time from hospital arrival to intervention/operation did not change. During the pandemic, 59.6% of surgical patients received interventions/operations within 6 hours of hospital arrival. In Cox’s proportional hazard modeling, the hazard ratio associated with the pandemic was 1.002 (0.778–1.292) for medical patients and 1.178 (0.783–1.772) for surgical patients.

Conclusion

Our triage system maintained the care required by critically ill non-COVID-19 patients undergoing CRRT at our institution.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00693-7.

Worsening or improving hypoalbuminemia during continuous renal replacement therapy is predictive of patient outcome: a single-center retrospective study

Background

Hypoalbuminemia at the initiation of continuous renal replacement therapy (CRRT) is a risk factor for poor patient outcomes. However, it is unknown whether the patterns of changes in serum albumin levels during CRRT can be used to predict patient outcomes.

Methods

This retrospective study analyzed data that had been consecutively collected from January 2016 to December 2020 at the Third Affiliated Hospital. We included patients with acute kidney injury who received CRRT for ≥ 72 h. We divided the patients into four groups based on their serum albumin levels (albumin ≥ 3.0 g/dL or < 3.0 g/dL) at the initiation and termination of CRRT.

Results

The 793 patients in this study were categorized into the following albumin groups: persistently low, 299 patients (37.7%); increasing, 85 patients (10.4%); decreasing, 195 patients (24.6%); and persistently high, 214 patients (27.1%). In-hospital mortality rates were highest in the persistently low and decreasing groups, followed by the increasing and persistently high groups. The hazard ratio for in-hospital mortality was 0.481 (0.340–0.680) in the increasing group compared to the persistently low group; it was 1.911 (1.394–2.620) in the decreasing group compared to the persistently high group. The length of ICU stay was 3.55 days longer in the persistently low group than in the persistently high group.

Conclusions

Serum albumin levels changed during CRRT, and monitoring of patterns of change in serum albumin levels is useful for predicting in-hospital mortality and the length of ICU stay.

Clinical features and outcomes of elderly patients with antineutrophil cytoplasmic antibody-positive vasculitis: a single-center retrospective study

Background

We aimed to investigate the clinical characteristics and outcomes of patients aged ≥65 years with antineutrophil cytoplasmic autoantibody (ANCA)-positive ANCA-associated vasculitis (AAV) in Korea.

Methods

Seventy patients diagnosed with ANCA-positive AAV from 2006 to 2019 at a single center were analyzed and categorized into younger (aged <65 years) or elderly (aged ≥65 years) groups. Initial induction treatments were investigated according to age group. All-cause mortality and kidney outcomes were evaluated.

Results

After categorization by age, 34 (48.6%) and 36 patients (51.4%) were in the younger and elderly groups, respectively. In the elderly group, more patients were treated with oral cyclophosphamide (CYC) (30.6%) than with intravenous CYC (19.4%). During a median follow-up of 14.6 months (range, 3.0–53.1 months), 13 patients died (elderly group: 11 patients, 84.6%). In the elderly group, older age (hazard ratio [HR], 1.44; 95% confidence interval [CI], 1.09–1.90; p = 0.01), lower hemoglobin (HR, 0.21; 95% CI, 0.08–0.60; p = 0.003), and higher serum creatinine level (HR 14.17; 95% CI, 1.29–155.84; p = 0.03) were significant risk factors for all-cause mortality after adjustment. Oral CYC + steroid treatment was associated with decreased all-cause mortality compared to untreated induction immunosuppressants (HR, 0.01; 95% CI, 0.001–0.47; p = 0.02). Kidney failure or kidney recovery outcomes were not significantly different between the younger and elderly groups.

Conclusion

Patients aged ≥65 years had higher mortality rates than younger patients, and mortality was associated with older age, lower hemoglobin, higher serum creatinine level, and nontreatment compared to oral CYC + steroids.

Pembrolizumab-induced focal segmental glomerulosclerosis: A case report

RATIONALE

Focal segmental glomerulosclerosis (FSGS) is the most common primary glomerular disorder that leads to end-stage kidney disease. Pembrolizumab, an immune checkpoint inhibitor, is an anti-programmed death 1 (PD-1) immunoglobulin G4 antibody approved for the treatment of advanced melanoma and can cause various renal immune-related adverse events (AEs), including acute kidney injury. Several cases of anti PD-1 therapy-induced glomerulonephritis have been reported so far, but FSGS has seldom been reported.

PATIENT CONCERNS

46-year old woman presented to our hospital with generalized edema.

DIAGNOSES

Laboratory examination revealed features of nephrotic syndrome, and kidney biopsy confirmed FSGS. After other etiological factors of secondary FSGS were ruled out, she was diagnosed with FSGS caused by pembrolizumab.

INTERVENTIONS

She did not resume treatment with pembrolizumab and was treated with irbesartan and furosemide according to the American Society of Clinical Oncology Practice guidelines.

OUTCOMES

After 2 months, the features of nephrotic syndrome resolved.

LESSONS

This case provides valuable insight into the etiology of FSGS that can occur as a renal immune-related AE of PD-1 inhibitor therapy. Therefore, patients should undergo evaluation for renal function and urinalysis at baseline and after treatment. If patients treated with PD-1 inhibitors present with renal injury and/or unexplained proteinuria >1 g/day, we would recommend a kidney biopsy to determine the underlying cause and establish an appropriate therapeutic plan.

Immunoglobulin A nephropathy in a patient with neurofibromatosis type 1: A case report and literature review

RATIONALE

Neurofibromatosis type 1 (NF-1) is an autosomal-dominant neurocutaneous disorder that affects the skin, bones, and nervous system. The most common manifestation of kidney involvement is renal artery stenosis; glomerulonephritis is extremely rare. In this case report, we present a patient with NF-1 and immunoglobulin A nephropathy (IgAN).

PATIENT CONCERNS

A 51-year-old Korean man previously diagnosed with NF-1 presented with persistent proteinuria and hematuria identified during a routine medical check-up. He had no history of hypertension or diabetes, and denied a history of alcohol use or smoking.

DIAGNOSIS

The contrast-enhanced computed tomography scan revealed normal-sized kidneys and no evidence of renal artery stenosis. On the day of the kidney biopsy, laboratory tests showed a serum creatinine level of 1.1 mg/dL, urine protein/creatinine ratio of 1.3 g/g, and urine red blood cell count of >10 to 15/HPF. The kidney biopsy sample revealed IgAN grade III, according to Lee glomerular grading system.

INTERVENTION

The patient was advised to take 4 mg of perindopril.

OUTCOME

Three months after the treatment, the urine protein/creatinine ratio decreased to 0.6 g/g, with no change in the serum creatinine level (1.03 mg/dL).

LESSONS

A genetic link between NF-1 and IgAN or other glomerular diseases is not established. However, activation of the mTOR pathway may explain this association.

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.

Clinical outcomes and prognostic factors of mortality in liver cirrhosis patients on continuous renal replacement therapy in two tertiary hospitals in Korea

Background

Data on liver cirrhosis (LC) patients undergoing continuous renal replacement therapy (CRRT) are lacking despite of the dismal prognosis. We therefore evaluated clinical characteristics and predictive factors related to mortality in LC patients undergoing CRRT.

Methods

We performed a retrospective observational study at two tertiary hospitals in Korea. A total of 229 LC patients who underwent CRRT were analyzed. Patients were classified into survivor and non-survivor groups. We used multivariable Cox regression analyses to identify predictive factors of in-hospital mortality.

Results

During a median follow-up of 5 days (interquartile range, 1-19 days), in-hospital mortality rate was 66.4%. In multivariable analysis, the Acute Physiology and Chronic Health Evaluation II (APACHE II) score (hazard ratio [HR], 1.03; 95% confidence interval [CI], 1.01-1.06; p = 0.02), Model for End-Stage Liver Disease (MELD) score (HR, 1.08; 95% CI, 1.04-1.11; p > 0.001), and delivered CRRT dose (HR, 0.95; 95% CI, 0.92-0.98; p = 0.002) were significant risk factors for in-hospital mortality. Patients with a CRRT delivered dose < 25 mL/kg/hr had a higher mortality rate than those with a delivered dose > 35 mL/kg/hr (HR, 3.13; 95% CI, 1.62-6.05; p = 0.001). Subgroup analysis revealed that a CRRT delivered dose > 25 mL/kg/hr was a significant risk factor for in-hospital mortality among LC patients with a MELD score ≥ 30.

Conclusion

High APACHE II score, high MELD score, and low delivered CRRT dose were significant risk factors for in-hospital mortality. CRRT delivered dose impacted mortality significantly, especially in patients with a MELD score ≥ 30.

Metabolic Acidosis Is an Independent Risk Factor of Renal Progression in Korean Chronic Kidney Disease Patients: The KNOW-CKD Study Results

Background: We aimed to evaluate serum bicarbonate as a risk factor for renal progression, cardiovascular events, and mortality in Korean CKD patients.

Methods: We analyzed 1,808 participants from a Korean CKD cohort whose serum bicarbonate levels were measured at enrollment. Serum bicarbonate levels were categorized as low, lower normal, higher normal, and high (total carbon dioxide <22, 22–26, 26.1–29.9, and ≥30 mmol/L, respectively) groups. Metabolic acidosis was defined as a serum bicarbonate level <22 mmol/L. The primary outcome was renal events defined as doubling of serum creatinine, 50% reduction of eGFR from the baseline values, or development of end-stage kidney disease. The secondary outcome consisted of cardiovascular events and death. In addition, patients whose eGFR values were measured more than three times during the follow-up period were analyzed for eGFR decline. The rapid decline in eGFR was defined as lower than the median value of the eGFR slope.

Results: The mean serum bicarbonate level was 25.7 ± 3.7 mmol/L and 240 (13.2%) patients had metabolic acidosis. During the follow-up period of 55.2 ± 24.1 months, 545 (30.9%) patients developed renal events and 187 (10.6%) patients developed a composite of cardiovascular events and death. After adjustment, the low serum bicarbonate group experienced 1.27 times more renal events than the lower normal bicarbonate group [hazard ratio (HR): 1.27; 95% CI: 1.01–1.60, P = 0.043]. There was no significant association between the bicarbonate groups and the composite outcome of cardiovascular events and death. The low bicarbonate group showed a significantly rapid decline in eGFR [odds ratio (OR): 2.12; 95% CI: 1.39–3.22, P < 0.001] compared to the lower normal bicarbonate group.

Conclusions: Metabolic acidosis was significantly associated with increased renal events and a rapid decline in renal function in Korean predialysis CKD patients.

Effect of Phoxilium on prognostic predictors in patients undergoing continuous venovenous hemodiafiltration

Background

Phosphorus-containing dialysis solution is used to prevent hypophosphatemia in patients undergoing continuous venovenous hemodiafiltration (CVVHDF). This study evaluated the effect of phosphorus-containing dialysis solution on mortality in patients undergoing CVVHDF based on changes in phosphorus and red cell distribution width-coefficient of variation (RDW-CV) levels.

Methods

We included 272 patients with acute kidney injury (AKI) who underwent CVVHDF at the medical intensive care unit from 2017 to 2019 and classified them according to Phoxilium (Baxter Healthcare Ltd.), as a phosphorus-containing dialysis solution, use within 48 hours after CVVHDF initiation. Clinical data were collected at baseline and 48 hours after CVVHDF initiation. The primary outcome was all-cause mortality during the follow-up period.

Results

The non-Phoxilium (NP) group had higher phosphorus and lower RDW-CV levels than the Phoxilium (P) group (phosphorus, 7.3 ± 4.3 vs. 5.0 ± 2.8 mg/dL; RDW-CV, 14.6 ± 1.9 vs. 15.7 ± 2.6%; all p < 0.001). In the multivariable Cox proportional hazard regression of the NP group, an increase in phosphorus and RDW-CV at 48 hours of CVVHDF was associated with mortality (delta phosphorus: median, >0 mg/dL vs. <-2.0 mg/dL; hazard ratio [HR], 8.62; 95% confidence interval [CI], 2.10-35.32; p = 0.003/delta RDW-CV: median, >0% vs. <-0.2%; HR, 4.34; 95% CI, 1.49-13.18; p = 0.008). Meanwhile, in the P group, an increase in delta RDW-CV was associated with mortality (delta RDW-CV: >0% vs. >-0.2% and <0%; HR, 2.65; 95% CI, 1.12-6.24; p = 0.03), while an increase in delta phosphorus was not.

Conclusion

In patients with AKI undergoing CVVHDF, the risk factors for all-cause mortality differed according to the initial phosphorus levels and use of Phoxilium.

Role of Akt1 in renal fibrosis and tubular dedifferentiation during the progression of acute kidney injury to chronic kidney disease

BACKGROUND/AIMS

Acute kidney injury (AKI) is an underestimated yet important risk factor for the development of chronic kidney disease (CKD), characterized by tubulointerstitial fibrosis and tubular dedifferentiation. Tubular dedifferentiation, which is associated with the loss of epithelial markers and the gain of mesenchymal features, is thought to be involved in tubulointerstitial fibrosis. As protein kinase B/Akt is involved in the development of CKD, we investigated the role of Akt1, one of the three Akt isoforms, in a murine model of AKI-to-CKD progression.

METHODS

We subjected C57BL/6 male mice to unilateral ischemia-reperfusion injury (UIRI) and harvested their kidneys after 6 weeks. Mice were divided into four groups, namely, wild-type (WT) UIRI, Akt1-/- UIRI, WT sham, and Akt1-/- sham.

RESULTS

Akt1 (but not Akt2 or Akt3) was markedly activated in WT UIRI mice than in WT sham mice. Tubulointerstitial fibrosis and tubular dedifferentiation significantly increased in WT UIRI mice, but were attenuated in Akt1-/- UIRI mice. Both WT UIRI and Akt1-/- UIRI mice showed markedly upregulated transforming growth factor-β1 (TGF-β1)/Smad signaling compared with WT sham mice. However, TGF-β1/Smad expression did not differ between the two groups. The levels of phosphorylated GSK-3β, β-catenin, and Snail were attenuated in Akt1-/- UIRI mice compared with those in WT UIRI mice.

CONCLUSION

Deletion of Akt1 results in the attenuation of renal fibrosis and tubular dedifferentiation, independent of TGF-β1/Smad signaling, during AKI-to-CKD progression in a UIRI without contralateral nephrectomy model. Thus, Akt1 may serve as a therapeutic target in AKI-to-CKD progression.

Association between serum uric acid and left ventricular hypertrophy/left ventricular diastolic dysfunction in patients with chronic kidney disease

Background

The level of serum uric acid (SUA) has been reported to be associated with left ventricular hypertrophy (LVH) and left ventricular diastolic dysfunction (LVDD). However, this association remains unclear in patients with chronic kidney disease (CKD).

Methods

A total of 1025 patients with pre-dialysis CKD with preserved left ventricular systolic function were enrolled in this cross-sectional study. The LVH and LVDD were assessed using two-dimensional echocardiography and tissue Doppler imaging. The associations of LVH/LVDD with clinical and laboratory variables were investigated using univariable and multivariable logistic regression analyses.

Results

In a multivariable analysis, the SUA level was an independent predictor of LVH (odds ratio [OR]: 1.40, 95% confidence interval [CI]: 1.31–1.50, P < 0.001). In addition, patient age, systolic blood pressure, intact parathyroid hormone levels, and left atrial volume index levels were independent predictors of LVH. The SUA level was also an independent predictor of LVDD (OR: 1.93, 95% CI: 1.53–2.43, P < 0.001). Furthermore, systolic blood pressure and left atrial volume index levels were an independent predictor of LVDD. Receiver-operating characteristic curve analysis showed that the best cutoff values of SUA levels for identifying LVH and LVDD were ≥ 7.5 mg/dL and ≥ 6.3 mg/dL, respectively.

Conclusion

The SUA level was an independent predictor of LVD and LVDD in patients with CKD, suggesting that SUA could be a biomarker for LVH and LVDD.

Impact of nutritional index on contrast-associated acute kidney injury and mortality after percutaneous coronary intervention

The risk of malnutrition in acute kidney injury and mortality in coronary artery disease patients has not been studied. This study aimed to evaluate whether nutritional status assessed by Onodera's prognostic nutritional index (PNI) was related to percutaneous coronary intervention (PCI) outcomes. A total of 3731 patients who received PCI between January 2010 and December 2018 were included. The relationship between PNI at the time of PCI and the occurrence of contrast-associated acute kidney injury (AKI) and all-cause death was evaluated using logistic regression and Cox proportional hazards models, respectively. AKI occurred in 271 patients (7.3%). A low PNI was independently associated with an increased risk of AKI on multivariate logistic regression analysis (OR 0.96, 95% CI 0.94-0.98, P = 0.001). During the median follow-up of 4.3 years, Kaplan-Meier analysis showed that patients with AKI/low PNI < 47.8 had a higher death rate. After adjusting for various risk factors, a low PNI was a significant risk factor for mortality (HR 0.98, CI 0.96-0.99, P = 0.003). A low level of PNI was associated with increased mortality, especially in the group aged over 70 years and female sex. PNI was closely associated with acute kidney outcomes and patient mortality after PCI.

Dialysis unit blood pressure two hours after hemodialysis is useful for predicting home blood pressure and ambulatory blood pressure in maintenance hemodialysis patients

This study aimed to determine which BP measurement obtained in the HD unit correlated best with home BP and ambulatory BP monitoring (ABPM). We retrospectively analyzed data from 40 patients that received maintenance HD who had available home BP and ABPM data. Dialysis unit BPs were the averages of pre-, 2hr- (2 h after starting HD), and post-HD BP during a 9-month study. Home BP was defined as the average of morning and evening home BPs. Dialysis unit BP and home BP were compared over the 9-month study period. ABPM was performed once for 24 h in the absence of dialysis during the final 2 weeks of the study period and was compared to the 2-week dialysis unit BP and home BP. There was a significant difference between dialysis unit systolic blood pressure (SBP) and home SBP over the 9-month period. No significant difference was observed between the 2hr-HD SBP and home SBP. When analyzing 2 weeks of dialysis unit BP and home BP, including ABPM, SBPs were significantly different (dialysis unit BP > home BP > ABPM; P = 0.009). Consistent with the 9-month study period, no significant difference was observed between 2hr-HD SBP and home SBP (P = 0.809). The difference between 2hr-HD SBP and ambulatory SBP was not significant (P = 0.113). In conclusion, the 2hr-HD SBP might be useful for predicting home BP and ABPM in HD patients.

Median nerve swelling is an independent risk factor of carpal tunnel syndrome in chronic hemodialysis patients

Carpal tunnel syndrome (CTS) has a wide variety of underlying causes and occurs in association with dialysis. Early diagnosis is essential to prevent permanent nerve damage and functional sequelae. We evaluated the association between CTS and cross-sectional area (CSA) of the median nerve in chronic hemodialysis (HD) patients. Patients with end-stage renal disease on maintenance HD via arteriovenous fistula were enrolled. We divided 43 patients into two groups; patients diagnosed with CTS (n = 19) and patients without CTS (n = 24). The median nerve CSA was measured at the wrist (CSA-W) and forearm (CSA-F) by ultrasonography. Median nerve swelling was assessed by the wrist-to-forearm ratio (WFR). There were no significant differences in the underlying causes of chronic kidney disease and adequacy of dialysis between the two groups (p = NS). The patients with CTS showed significantly higher WFR than the patients without CTS (p = 0.001). Univariate Cox regression analysis revealed that WFR >1.25 (odds ratio, 6.30; 95% confidence interval, 1.44-27.45; p = 0.014) was associated with CTS in HD patients. The factors traditionally associated with CTS such as age, sex, diabetes, vintage of HD, β2-MG, intact PTH, and Kt/V were not associated with CTS. After adjustment for age and sex, we found a strong correlation between CTS and the WFR >1.25 (odds ratio, 10.8; 95% confidence interval, 1.85-62.4; p = 0.008). High WFR was associated with the development of CTS, and median nerve swelling was an independent risk factor of CTS in chronic HD patients.

Intradialytic Hypotension and Newly Recognized Peripheral Artery Disease in Patients Receiving Hemodialysis

RATIONALE & OBJECTIVE

Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Linking data from the US Renal Data System to the electronic health records of a large dialysis provider, we identified adult patients (≥18 years of age) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD.

EXPOSURE

The time-varying proportion of hemodialysis sessions with IDH defined as the nadir intradialytic systolic blood pressure <90 mm Hg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0% to <15%, 15% to <30%, and ≥30%.

OUTCOMES

Newly recognized PAD was ascertained using PAD diagnostic and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval.

ANALYTICAL APPROACH

To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted subdistribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure.

RESULTS

Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association between IDH and newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (vs 0%) was associated with a 24% (95% CI, 17%-32%) higher hazard than having newly recognized PAD in the subsequent 30 days.

LIMITATIONS

Unmeasured confounding; ascertainment of PAD from claims.

CONCLUSIONS

Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD.

Akt1 is involved in tubular apoptosis and inflammatory response during renal ischemia-reperfusion injury

Renal ischemia-reperfusion injury (IRI) is one of the major causes of acute kidney injury (AKI). Although Akt is involved in renal IRI, it is unclear as to which Akt isoform plays an important role in renal IRI. In this study, we investigated the role of Akt1 in renal IRI. We subjected the C57BL/6 male mice to unilateral IRI with contralateral nephrectomy. Two days after IRI, IRI-kidneys were harvested. The mice were divided into four groups: wild type (WT) IRI, Akt1^-/- IRI, WT sham, and Akt1^-/- sham. We found that Akt1, not Akt2 or Akt3, was markedly activated in WT IRI than in WT sham mice. The histologic damage score and serum creatinine level significantly increased in WT IRI mice, the increase being the highest in Akt1^-/- IRI mice. The number of TdT-mediated dUTP nick-end labeling (TUNEL)-positive tubular cells and expression of cleaved caspase-3/Bax were higher in Akt1^-/- IRI mice than in WT IRI mice. The expression of Bcl-2 was lower in Akt1^-/- IRI mice than in WT IRI mice. The expression of tumor necrosis factor-α/interleukin-6/interleukin-1β and number of F4/80-positive macrophages were markedly higher in Akt1^-/- IRI than in WT IRI mice. The expression of phosphorylated nuclear factor-κB p65 was also higher in Akt1^-/- IRI mice than in WT IRI mice. Our results show that Akt1 deletion exacerbates kidney damage as it increases tubular apoptosis and inflammatory response during renal IRI. Akt1 could be a potential therapeutic target for developing treatments against IRI-induced AKI.

Percutaneous peritoneal dialysis catheter implantation with no break-in period: A viable option for patients requiring unplanned urgent-start peritoneal dialysis

Background

Urgent-start peritoneal dialysis (PD) is applied to patients who need PD within two weeks but are able to wait for more than 48 hours before starting PD. To evaluate the usefulness of percutaneous PD catheter insertion in urgent-start PD, we reviewed the clinical outcomes of percutaneous catheter insertion with immediate start PD and surgical insertion with longer break-in time in Pusan National University Hospital.

Methods

This study included 177 patients who underwent urgent-start PD. Based on the PD catheter insertion techniques, the patients with urgent-start PD were divided into percutaneous (n = 103) and surgical (n = 74) groups. For the percutaneous group, a modified Seldinger percutaneous catheter insertion with immediate initiation of continuous ambulatory PD was performed by nephrologists.

Results

The percutaneous group showed higher serum urea nitrogen, creatinine, and lower serum albumin compared with the surgical group (P < 0.05). Ninety-day infectious and mechanical complications showed no significant differences between the two groups. Ninety-day peritonitis in the percutaneous group was 9.7% compared to 5.4% in the surgical group (P = not significant [NS]). Major leakage was 3.9% in the percutaneous group compared to 1.4% in the surgical group (P = NS). Overall infectious and mechanical complication-free survival was not significantly different between the two groups. The percutaneous group and surgical group showed no statistical difference with respect to catheter survival over the entire observation period (P = NS).

Conclusion

This study suggests that urgent-start PD can be applied safely with percutaneous catheter insertion by nephrologists with no break-in period.

Autoimmune hepatitis in a patient with immunoglobulin A nephropathy: A case report

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most commonly encountered glomerular disease in Asian countries. It has a broad clinical presentation, and it is frequently associated with other conditions. Chronic liver disease is well recognized as the leading cause of secondary IgAN. However, cases of IgAN associated with autoimmune hepatitis (AIH) have seldom been reported.

CASE SUMMARY

A 63-year-old Korean woman was admitted to Pusan National University Hospital for an evaluation of abdominal pain and elevated liver enzymes. Two weeks prior, she had presented to our hospital with proteinuria of approximately 1350 mg/d and hematuria and was diagnosed with IgAN. Autoimmune profiles were highly positive for antinuclear antibodies, and symptoms related to portal hypertension including ascites and peripheral edema were present. A diagnosis of AIH was made according to the simplified scoring system of the International Autoimmune Hepatitis Group. Despite immunosuppression with prednisolone and azathioprine, rapid deterioration of liver function led to end-stage liver disease. After a living-donor liver transplantation, liver function gradually improved, and she had maintained stable liver and kidney function at the six months follow-up.

CONCLUSION

Cases of secondary IgAN with chronic liver disease have been frequently reported in the literature but are rarely associated with AIH. We encountered an IgAN patient with concurrent progressive liver failure due to AIH.

P0547THE DELETION OF AKT1 ATTENUATES RENAL FIBROSIS AND TUBULAR EPITHELIAL-MESENCHYMAL TRANSITION DURING ACUTE KIDNEY INJURY TO CHRONIC KIDNEY DISEASE PROGRESSION

Background and Aims

Acute kidney injury (AKI) is an underestimated, yet important risk factor for the development of chronic kidney disease (CKD), which is characterized by the tubulointerstitial fibrosis and tubular epithelial-mesenchymal transition (EMT). Akt has been reported to be involved in renal fibrosis and EMT. Thus, we investigated the role of Akt1, one of the three Akt isoforms, in the murine model of AKI to CKD progression.

Method

We subjected the wild type and Akt1−/− mice to unilateral ischemia-reperfusion injury (UIRI). UIRI was induced by clamping the left renal artery for 30 min followed by reperfusion. After 6 weeks of UIRI, the renal fibrosis and EMT were assessed by histology, immunohistochemistry, and western blot.

Results

After 6 weeks after UIRI, we found that Akt1, not Akt2 or Akt3, was activated in UIRI-kidney. The tubulointerstitial fibrosis was significantly alleviated in Akt1−/− mice compared with the wild type (WT) mice. Besides, the deletion of Akt1 decreased the expression of the vimentin and α-SMA and increased the expression of E-cadherin, indicating the suppression of tubular EMT. However, there was no difference in the activity of TGF-β1/Smad signalling, which is the potent inducer of renal fibrosis and EMT, between WT mice and Akt1−/− mice. The deletion of Akt1 also increased the GSK-3β activity and decreased the expression of β-catenin, Snail, and twist1.

Conclusion

Our findings demonstrate that the deletion of Akt1 attenuates the renal fibrosis and tubular EMT independently of TGF-β1/Smad signalling during the AKI to CKD progression. Akt1 may be the therapeutic target against the AKI to CKD progression.

P0734THE DELETION OF AKT1 PROMOTES THE RENAL FIBROSIS IN THE MURINE MODEL OF UNILATERAL URETERAL OBSTRUCTION

Background and Aims

Previous studies have found the increased Akt activity in experimental renal fibrosis. We investigated the role of Akt1, one of the three Akt isoforms, in renal fibrosis using the murine model of unilateral ureteral obstruction (UUO).

Method

In vivo, we subjected the wild type and Akt1−/− mice to UUO. In vitro, gene silencing of Akt1 was achieved using the short hairpin RNA delivered by the lentiviral vector in immortalized human proximal tubular cells (HK2 cells) and rat kidney fibroblasts (NRK-49F cells).

Results

In immunohistochemical stain, the expression of Akt1 was significantly higher in obstructed kidneys of wild type mice compared with control sham kidneys and increased gradually as UUO progressed. The fibronectin, type I collagen, and heat shock protein 47 (HSP47) were markedly more expressed in obstructed kidneys of Akt1−/− mice than in those of the wild type mice. Transforming growth factor β1 (TGFβ1) was highly induced within 1 day of UUO in obstructed kidneys of Akt1−/− mice and the expression of TGFβ1 was significantly higher in the Akt1−/− mice than in the wild type mice as UUO progressed. Western blot showed that silencing of Akt1 increased the expression of TGFβ1, which was enhanced by angiotensin II stimulation in HK2 cells, but not in NRK-49F cells. Immunohistochemical stain demonstrated that the expression of cleaved caspase-3 in renal tubules was significantly higher in the Akt1−/− mice than in the wild type mice. Western blot showed that silencing of Akt1 increased the expression of cleaved caspase-3 in HK2 cells, but not in NRK-49F cells.

Conclusion

Our findings suggest that the deletion of Akt1 might contribute to tubulointerstitial fibrosis and tubular apoptosis via TGFβ1 induction. We also showed that TGFβ1 upregulation by genetic deletion of Akt1 is associated with activation of STAT3 independently of the TGFβ1/Smad signaling pathway.

Multifunctional and Sustainable Fe-Iminopyridine Complexes for the Synthesis of Cyclic Carbonates

The use of multifunctional and sustainable Fe catalysts for the formation of cyclic carbonates from epoxides and carbon dioxide at 80 °C and 3 bar pressure is presented. The optimal catalyst possesses a halide counteranion and a hydrogen bond donor to activate the epoxide for ring opening, affording a single-component, cocatalyst-free catalytic system.

Initial Experience With Hand-Assisted Laparoscopic Living Donor Nephrectomy: Training and Clinical Practice as a General Surgeon

BACKGROUND

To analyze our initial results of hand-assisted laparoscopic living donor nephrectomy, executed by a skilled gastrointestinal surgeon.

METHODS

A total of 22 consecutive patients underwent the hand-assisted laparoscopic living donor nephrectomy between December 2014 and January 2017. We retrospectively analyze the patient's perioperative clinical data, which were collected prospectively.

RESULTS

The right kidney was harvested in 12 patients. The mean operative time and intraoperative blood loss was 241.0 ± 43.4 minutes (range, 140-310 min) and 293.2 ± 203.1 mL (range, 50-700 mL), respectively. The mean warm ischemic time was 288.4 ± 103.4 seconds (range, 179-610 s). Postoperative complications included chyle leakage in 2 patients who were left kidney donors and oliguria in 1 patient who was a right kidney donor. All patients recovered with conservative care, and the mean hospital stay was 7.5 ± 1.7 days. The mean creatinine level was 0.7 ± 0.2 mg/dL before surgery, 1.1 ± 0.3 mg/dL at postoperative day (POD) 1, and 1.0 ± 0.2 mg/dL after discharge. The mean glomerular filtration rate was 97.9 ± 18.2 mL/min/1.73 m² before surgery, 60.7 ± 10.4 at POD 1, and 67.3 ± 11.1 after discharge. Operation time was not associated with patient body mass index and case number. No significant differences, other than postoperative complications, were found in the perioperative data for the side of kidney donation.

CONCLUSION

A skilled surgeon with experience in laparoscopic abdominal surgery (such as gastrectomy or colectomy) might safely perform hand-assisted donor nephrectomy. However, we could not identify a clear case number to complete the learning curve.

Plasma neutrophil gelatinase-associated lipocalin is independently associated with left ventricular hypertrophy and diastolic dysfunction in patients with chronic kidney disease

Background

Cardiovascular disease (CVD) is a leading cause of death in patients with chronic kidney disease (CKD). Left ventricular hypertrophy (LVH) and left ventricular diastolic dysfunction (LVDD) are known as predictors of CVD in these patients. Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of acute kidney injury. Recently, elevated NGAL levels have been reported in patients with CVD. This study aimed to evaluate the association between plasma NGAL levels and LVH/LVDD in patients with CKD.

Methods

This study included 332 patients with pre-dialysis CKD (estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m²). Two-dimensional echocardiography was performed to measure the left ventricular mass index (LVMI). Tissue Doppler imaging was used to measure early mitral inflow velocity (E) and the peak early mitral annular velocity (E'). Diastolic function was estimated using E' and the ratio of E to E' (E/E'). The associations of echocardiographic index with clinical and laboratory variables (age, sex, diabetes, hypertension, eGFR, albumin, uric acid, calcium, phosphate, total cholesterol, hemoglobin, C-reactive protein, intact parathyroid hormone (PTH), the inferior vena cava collapse index (IVCCI) < 50%, and plasma NGAL) were investigated using univariate and multivariate analyses.

Results

In multivariate logistic regression analysis, plasma NGAL was an independent predictor of LVH (OR: 1.02, 95% CI: 1.01–1.02), P < 0.001). In addition, hypertension, intact PTH, and IVCCI < 50% were independent predictors of LVH. Plasma NGAL (OR: 1.02, 95% CI: 1.01–1.02, P < 0.001) was also an independent factor of LVDD. Furthermore, hypertension, intact PTH, and IVCCI < 50% were independent predictors of LVDD. Receiver operating characteristic curve analysis (area under the curve: 0.835, 95% CI: 0.792–0.879) showed the best cutoff value of plasma NGAL for identifying LVDD was ≥ 258 ng/ml with an associated sensitivity of 77.6% and a specificity of 87.6%.

Conclusion

Plasma NGAL levels were independent predictors of LVH and LVDD in patients with pre-dialysis CKD, suggesting that plasma NGAL could be a biomarker for LVH and LVDD in these patients.

Importance of Timed and Detailed Evaluation of Kidney Transplantation Candidates

Kidney transplant recipients are at increased risk of cardiovascular morbidity and malignant neoplasm, and meticulous evaluation of potential recipients is needed to minimize risks of complications after transplantation. The purpose of this study was to analyze the results of preoperative assessments and document the importance of timed and detailed examinations.

METHODS

Medical records of patients evaluated as kidney transplant candidates from January 2015 to September 2017 were retrospectively collected and analyzed.

RESULTS

Of the 216 patients evaluated during the study period, 135 (62.5%) were male, 112 (51.9%) had diabetes mellitus, 163 (75.5%) had hypertension, 31 (14.4%) had a cardiovascular event history, and 7 (3.2%) had previous history of malignant neoplasms. Mean (SD) patient age was 50.7 (10.8) years. All 216 recipient candidates underwent echocardiography. Mean (SD) ejection fraction was 57.8% (5.9%), and 48 candidates (22.2%) showed regional wall motional abnormality. Coronary angiography was performed on 81 candidates, and in 57 (70.4%) of these, coronary artery disease was detected. Malignant neoplasms were detected in 10 (4.6%) candidates. Kidney transplantation was performed on 55 candidates. One recipient died of Pneumocystis jirovecii pneumonia at 15 months after kidney transplant, but there was no death-censored graft failure, newly detected malignant neoplasm, or cardiovascular event over a mean (SD) follow-up duration of 15.5 (8.6) months.

CONCLUSION

Evaluation of kidney transplant candidates resulted in diagnoses of malignant neoplasms in 4.6% of patients and coronary artery disease in 26.4% of patients. The results of this study demonstrate candidates for kidney transplant should undergo detailed preoperative evaluation.

The Relationship between Intradialytic Hypotension and Hospitalized Mesenteric Ischemia: A Case-Control Study

BACKGROUND AND OBJECTIVES

Mesenteric ischemia is a rare but devastating condition caused by insufficient blood supply to meet the demands of intestinal metabolism. In patients with ESKD, it can be difficult to diagnose and has a >70% mortality rate. Patients on hemodialysis have a high prevalence of predisposing conditions for mesenteric ischemia, but the contribution of intradialytic hypotension, a potential modifiable risk factor, has not been well described.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used data from the US Renal Data System to identify 626 patients on hemodialysis with a hospitalized mesenteric ischemia event (cases). We selected 2428 controls in up to a 1:4 ratio matched by age, sex, black race, incident dialysis year, diabetes mellitus, coronary artery disease, and peripheral artery disease. We used six different definitions of intradialytic hypotension on the basis of prior studies, and categorized patients as having had intradialytic hypotension if ≥30% of hemodialysis sessions in the 30 days before the event met the specified definition.

RESULTS

The proportion of patients with intradialytic hypotension varied depending on its definition: from 19% to 92% of cases and 11% to 94% of controls. Cases had a higher adjusted odds (1.82; 95% confidence interval, 1.47 to 2.26) of having had intradialytic hypotension in the preceding 30 days than controls when using nadir-based intradialytic hypotension definitions such as nadir systolic BP <90 mm Hg. To examine a potential dose-response association of intradialytic hypotension with hospitalized mesenteric ischemia, we categorized patients by the proportion of hemodialysis sessions having intradialytic hypotension, defined using the Nadir90 definition (0%, 1%-9%, 10%-29%, 30%-49%, and ≥50%), and found a direct association of proportion of intradialytic hypotension with hospitalized mesenteric ischemia (P-trend<0.001).

CONCLUSIONS

Patients with hospitalized mesenteric ischemia had significantly higher odds of having had intradialytic hypotension in the preceding 30 days than controls, as defined by nadir-based definitions.

The expression of two isoforms of matrix metalloproteinase-2 in aged mouse models of diabetes mellitus and chronic kidney disease

Background

This study was undertaken to explore the effects of aging on the kidneys in mouse models of diabetes and chronic kidney disease (CKD), and to compare the expression of two isoforms of matrix metalloproteinase-2 (MMP-2)–secretory full-length MMP-2 and intracellular N-terminal truncated MMP-2 (NTT-MMP-2)–in these models.

Methods

Two experimental ICR mouse models were used: a streptozotocin (STZ)-induced type 1 diabetes mellitus model and a 5/6 nephrectomized (5/6Nx) CKD model. The abundance of each isoform of MMP-2 was determined by quantitative polymerase chain reaction (qPCR), and functional analyses were conducted. Moreover, the protein levels of the two MMP-2 isoforms were determined semi-quantitatively by immunohistochemical staining, and their association with tissue damage was assessed.

Results

Both isoforms of MMP-2 were upregulated in the kidney tissues of STZ-induced diabetic mice and 5/6Nx mice, irrespective of age. Characteristically, NTT-MMP-2 protein expression was elevated in old control mice, in line with the qPCR results. NTT-MMP-2 expression was limited to the renal cortex, and to the tubulointerstitial area rather than the glomerular area. In terms of tissue damage, tubulointerstitial fibrosis was more severe in old 5/6Nx mice than in their young counterparts, whereas glomerulosclerosis was comparable in old and young 5/6Nx mice.

Conclusion

The intracellular isoform of MMP-2 was induced by ageing, irrespective of the presence of diabetes or CKD, and its induction may be related to tubulointerstitial fibrosis in chronic kidney disease.

The two isoforms of matrix metalloproteinase- 2 have distinct renal spatial and temporal distributions in murine models of types 1 and 2 diabetes mellitus

Background

We recently reported on the enhanced tubular expression of two discrete isoforms of the MMP-2 (full length and N-terminal truncated, FL-MMP-2, NTT-MMP-2) in a murine model and human diabetic kidneys. In the present study, we examined in more detail the temporal and spatial distributions of MMP-2 isoform expression in murine models of Type 1 and Type 2 diabetes mellitus.

Methods

Diabetic models were streptozotocin (STZ)-induced diabetes (Type 1 diabetes mellitus) and db/db mice (Type 2 diabetes mellitus). We quantified the abundance of two isoforms of MMP-2 transcripts by qPCR. A spatial distribution of two isoforms of MMP-2 was analyzed semi-quantitatively according to time after injection of STZ and with increasing age of db/db mice. Furthermore, immunohistochemistry for nitrotyrosine was performed to examine a potential association between oxidative stress and MMP-2 isoform expression.

Results

Both isoforms of MMP-2 were upregulated in whole kidneys from STZ and db/db mice. In the case of FL-MMP-2, mRNA levels significantly increased at 12 and 24 weeks in STZ mice, while the isoform expression was significantly increased only at 16 weeks, in the db/db mice. FL-MMP-2 protein levels increased in the cortices and outer medullae of both STZ and db/db mice as a function of the duration of diabetes. For NTT-MMP-2, mRNA levels increased earlier at 4 weeks in STZ mice and at 10 weeks of age in db/db mice. The expression of NTT-MMP-2 also increased, primarily in the cortices of STZ and db/db mice, as a function of the duration of diabetes. Quantitatively, these findings were consistent with the qPCR results in the case of NTT-MMP-2, respectively (STZ 24 weeks, 3.24 ± 3.70 fold; 16 weeks db/db, 4.49 ± 0.55 fold). In addition, nitrotyrosine was expressed primarily in cortex as compared to medulla as a function of the duration of diabetes similar to NTT-MMP-2 expression.

Conclusions

Two isoforms of MMP-2 are highly inducible in two diabetic murine models and become more abundant as a function of time. As the expression patterns were not the same in the two isoforms of MMP-2, it is possible that each isoform has a discrete role in the development of diabetic renal injury.

Low 1,25-dihydroxyvitamin D level is associated with erythropoietin deficiency and endogenous erythropoietin resistance in patients with chronic kidney disease

PURPOSE

Erythropoietin (EPO) deficiency and resistance to endogenous EPO is an important pathophysiological feature in anemia of chronic kidney disease (CKD). Low 1,25 dihydroxyvitamin D [1,25(OH)₂D] level is known to contribute to anemia of CKD. We aimed to investigate the associations between serum 1,25(OH)₂D and anemia, EPO deficiency, and endogenous EPO resistance in patients with CKD.

METHODS

This study included 409 patients with CKD [glomerular filtration rate (GFR) < 60 ml/min/1.73 m²] who were not on dialysis therapy. Patients on exogenous EPO therapy and patients with iron deficiencies were excluded. Endogenous EPO resistance was assessed by calculating the ratio of endogenous EPO to hemoglobin (Hb) (endogenous EPO/Hb ratio). The associations of Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio with clinical and laboratory variables were investigated by univariate and multivariate analyses.

RESULTS

In univariate analysis, serum 1,25(OH)₂D level was correlated with the Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio. Multiple regression analysis revealed that the serum 1,25(OH)₂D level remained significantly associated with the Hb level (β = 0.532, P < 0.001), endogenous EPO level (β = 0.149, P = 0.010), and the endogenous EPO/Hb ratio (β = - 0.187, P = 0.002), even after adjusting for other confounding factors, including the levels of parathyroid hormone and the inflammatory marker C-reactive protein.

CONCLUSION

The serum 1,25(OH)₂D level exhibited significant associations with anemia, EPO deficiency, and endogenous EPO resistance in CKD patients. These associations were independent of secondary hyperparathyroidism and inflammation status.

Long-term outcomes in acute kidney injury patients who underwent continuous renal replacement therapy: a single-center experience

INTRODUCTION

Acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) is the most severe form of AKI associated with poor short- and long-term patient outcomes. The aim of this study was to evaluate the variables associated with long-term patient survival in our clinic.

METHODS

This was a single-center retrospective study with AKI survivors who received CRRT from March 2011 to February 2015. During the study period, all consecutive AKI survivors who underwent CRRT were included. Patients on maintenance dialysis prior to CRRT were excluded. Data were collected by reviewing the patients' medical charts. Long-term follow-up data were gathered through February 2018.

RESULTS

A total of 430 patients were included, and 62.8% of the patients were male. The mean age of the patients was 63.4 ± 14.6 years. The mean serum creatinine level at the time of CRRT initiation was 3.5 ± 2.5 mg/dL. At the time of discharge, the mean eGFR and serum creatinine levels were 58.4 ± 46.7 and 1.7 ± 1.6 mg/dL, respectively. After 3 years, 44.9% of the patients had survived. When we investigated the factors associated with long-term patient mortality, a longer stay in the ICU [OR 1.034 (1.016-1.053), p < 0.001], a history of cancer [OR 3.830 (1.037-3.308), p = 0.037], a prolonged prothrombin time [OR 1.852 (1.037-3.308), p = 0.037] and a lower eGFR at the time of discharge [OR 0.988 (0.982-0.995), p = 0.001] were independently associated with long-term patient mortality.

CONCLUSION

Our study demonstrates that long-term mortality after CRRT is associated with longer ICU stays and lower eGFRs at the time of hospital discharge. Our data imply the importance of renal recovery for long-term survival of AKI patients treated with CRRT.

Change in kidney function after unilateral adrenalectomy in patients with primary aldosteronism: identification of risk factors for decreased kidney function

PURPOSE

Glomerular filtration rate (GFR) has been reported to decrease after unilateral adrenalectomy in patients with primary aldosteronism (PA). The aim of this study was to identify clinical predictors for decreased GFR after adrenalectomy in patients with PA.

METHODS

The records of 187 patients (98 patients with PA and 89 with non-PA adrenal disease) who were followed up for at least 6 months after unilateral adrenalectomy were retrospectively analyzed. Estimated GFR (eGFR) was investigated at 1, 3, and 6 months postoperatively. Preoperative risk factors for eGFR% decline at 1 month ([preoperative eGFR-eGFR at 1 month]/preoperative eGFR × 100) and postoperative CKD development were investigated.

RESULTS

The eGFR decreased significantly at 1 month and remained stable in the PA group. However, there were no significant changes in eGFR in the non-PA group over the 6-month period. In the PA group, a high preoperative eGFR and high aldosterone to renin ratio (ARR) were independently associated with eGFR% decline at 1 month. In patients with PA but without preoperative CKD (n = 68), a low preoperative eGFR and high ARR were independent risk factors for developing postoperative CKD. The best preoperative cut-off values of eGFR and ARR for predicting the development of postoperative CKD were ≤ 102 ml/min/1.73 m² and ≥ 448 ng/dl:ng/ml/h, respectively.

CONCLUSIONS

Renal function deteriorated significantly after unilateral adrenalectomy in patients with PA. Clinicians must pay attention to postoperative renal function in PA patients at elevated risk of developing decreased kidney function.

Primary Glomerulonephritis with Unique C4d Deposition and Concurrent Non-infectious Intermediate Uveitis: a Case Report and Literature Review

C4 glomerulopathy is a recently introduced entity that presents with bright C4d staining and minimal or absent immunoglobulin and C3 staining. We report a case of a 62-year-old man with C4 glomerulonephritis (GN) and uveitis. He presented to the nephrology department with proteinuria and hematuria. The patient also had intermediate uveitis along with proteinuria and hematuria. A kidney biopsy that was performed in light of continuing proteinuria and hematuria showed a focal proliferative, focal sclerotic glomerulopathy pattern on light microscopy, absent staining for immunoglobulin or C3 by immunofluorescence microscopy, with bright staining for C4d on immunohistochemistry, and electron-dense deposits on electron microscopy. Consequently, C4 GN was suggested as the pathologic diagnosis. Although laser microdissection and mass spectrometry for glomerular deposit and pathologic evaluation of the retinal tissue were not performed, this is the first report of C4 GN in Korea and the first case of coexisting C4 GN and uveitis in the English literature.

Light Chain Deposition Disease Associated With Multiple Myeloma Developing in Late Pregnancy

Preeclampsia is the most common cause of proteinuria with hypertension during pregnancy. Primary kidney disease and kidney disease secondary to systemic disorders may rarely occur during pregnancy, resulting in proteinuria. A 34-year-old woman was admitted to our hospital with abdominal distention and lower extremity edema. The pregnancy was terminated at the 24th week of gestation due to preterm labor. Even after the delivery, proteinuria and renal deterioration continued to progress. The M-peak was not found on serum and urine protein electrophoresis. The serum free light chains assay showed absolute elevation of lambda chains at 1013.9 mg/L with a decreased kappa to lambda ratio of 0.05. Kidney biopsy revealed light chain deposition disease with lambda light chain deposits on immunofluorescence. Bone marrow examination was compatible with multiple myeloma. To our knowledge, this is the first reported case of light chain deposition disease associated with multiple myeloma during pregnancy.

The role of the specialized team in the operation of continuous renal replacement therapy: a single-center experience

Background

The requirement of continuous renal replacement therapy (CRRT) is increasing with the growing incidence of acute kidney injury (AKI). The decision to initiate CRRT is not difficult if an adequate medical history is obtained. However, the handling and maintenance of CRRT constitute a labor-intensive intervention that requires specialized skills. For these reasons, our center organized a specialized CRRT team in March 2013. The aim of this study is to report on the role of a specialized CRRT team and to evaluate the team’s outcome.

Methods

This retrospective single-center study evaluated AKI patients who underwent CRRT in the intensive care unit (ICU) from March 2011 to February 2015. Patients were divided into two groups based on whether they received specialized CRRT team intervention. We collected information on demographic characteristics, laboratory parameters, SOFA score, CRRT initiation time, actual delivered dose and CRRT down-time. In-hospital mortality was defined by medical chart review. Binary logistic regression analysis was used to define factors associated with in-hospital mortality.

Results

A total of 1104 patients were included in this study. The mean patient age was 63.85 ± 14.39 years old, and 62.8% of the patients were male. After the specialized CRRT team intervention, there was a significant reduction in CRRT initiation time (5.30 ± 13.86 vs. 3.60 ± 11.59 days, p = 0.027) and CRRT down-time (1.78 ± 2.23 vs. 1.38 ± 2.08 h/day, p = 0.002). The rate of in-hospital mortality decreased after the specialized CRRT team intervention (57.5 vs. 49.2%, p = 0.007). When the multivariable analysis was adjusted, delayed CRRT initiation (HR 1.054(1.036–1.072), p < 0.001) was a significant factor in predicting in-hospital mortality, along with an increased SOFA score, lower serum albumin and prolonged prothrombin time.

Conclusions

Our study shows that specialized CRRT team intervention reduced CRRT initiation time, down-time and in-hospital mortality. This study could serve as a logical basis for implementing specialized CRRT teams hospital-wide.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0746-8) contains supplementary material, which is available to authorized users.