Association between serum osteoprotegerin level and renal prognosis in nondialysis patients with chronic kidney disease in the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (the KNOW-CKD Study)

Background

Osteoprotegerin is an important regulator of bone metabolism and vascular calcification. The association between serum osteoprotegerin level and chronic kidney disease (CKD) progression has not been elucidated. We investigated the prognostic value of serum osteoprotegerin levels in nondialysis CKD patients.

Methods

We analyzed 2,082 patients enrolled in the Korean Cohort Study for Outcomes in Patients with CKD between 2011 and 2016. Patients were divided into quartiles by their serum osteoprotegerin levels. The primary outcome was the occurrence of ≥1 of the following: dialysis initiation, kidney transplantation, a two-fold increase in serum creatinine level from baseline, or a 50% decrease in the estimated glomerular filtration rate (eGFR). Cox proportional hazard regression models were used to investigate the prognostic value of the serum osteoprotegerin level to CKD progression.

Results

The median follow-up period was 48.9 months, and 641 patients (30.8%) experienced the primary outcome. The hazard ratio of serum osteoprotegerin for renal progression in the full extended Cox proportional hazard model was 1.064 (95% confidence interval, 1.041–1.088). Subgroup analyses by age, presence of diabetes, and eGFR showed significant results consistent with the overall analysis results.

Conclusion

Serum osteoprotegerin level is independently associated with renal prognosis and could have prognostic importance in CKD progression.

Association of Circulating Osteoprotegerin Level with Blood Pressure Variability in Patients with Chronic Kidney Disease

Circulating osteoprotegerin (OPG) is a biomarker for cardiovascular complications that are closely related to chronic kidney disease (CKD). To investigate the association between circulating OPG level with long-term visit-to-visit blood pressure variability (BPV) in patients with pre-dialysis CKD, a total of 1855 subjects with CKD from stage 1 to pre-dialysis stage 5 from a prospective cohort were analyzed. Long-term visit-to-visit BPV was determined by average real variability (ARV), standard deviation (SD), and coefficient of variation (CoV) of systolic and diastolic blood pressure (SBP and DBP). ARV of SBP (Adjusted β coefficient 0.143, 95% confidence interval 0.021 to 0.264) was significantly associated with serum OPG level. Although SD and CoV of SBP were not significantly associated with serum OPG level in multivariate linear regression analyses, restricted cubic spline visualized the linear correlation of serum OPG level with all of ARV, SD, and CoV. The association between serum OPG level and DBP variability was not significant. Subgroup analyses revealed that the association of serum OPG with BPV is more prominent in the subjects with Charlson comorbidity index ≤3 and in the subjects without history of diabetes mellitus. In conclusion, circulating OPG level is potentially associated with long-term visit-to-visit BPV in patients with pre-dialysis CKD.

Underweight and Weight Change Increases End-Stage Renal Disease Risk in Patients with Diabetes: A Nationwide Population-Based Cohort Study

Weight variability has known as a risk factor for cardiovascular events and mortality. However, its effect on end-stage renal disease (ESRD) development remains controversial. We investigated the relationship between weight change and ESRD risk. Overall, 97,029 patients with DM aged >20 years were selected from the Korean National Health Screening Program 2009–2012. Weight change was defined as differences in body weight from the index year to 2 years later. Newly diagnosed ESRD was observed until 2017 end. Over a 5.1-year median follow-up period, ESRD was newly diagnosed in 7932 (4.81%) DM patients. BMI < 18.5 kg/m² and waist circumferences <85/80 and >100/95 cm were ESRD risk factors. ESRD risk increased with increasing weight change; ≥10% weight loss (hazard ratio [HR], 1.247) followed by ≥10% weight gain (1.247) was associated with a higher HR than ≤5% weight change after adjusting for several confounding factors. The association between weight change and ESRD risk in a subgroup analysis was significantly stronger in patients aged <65 years, without proteinuria, with BMI ≥ 25, with DM duration <5 years, and prescribed less than 3 classes of DM medication. Underweight patients showed higher ESRD risks than overweight patients. Weight loss >10% was associated with the fastest decline in renal function.

Vimentin Targeted Nano-gene Carrier for Treatment of Renal Diseases

BACKGROUND

Chronic kidney disease (CKD) is a global health problem, and there is no permanent treatment for reversing kidney failure; thus, early diagnosis and effective treatment are required. Gene therapy has outstanding potential; however, the lack of safe gene delivery vectors, a reasonable transfection rate, and kidney targeting ability limit its application. Nanoparticles can offer innovative ways to diagnose and treat kidney diseases as they facilitate targetability and therapeutic efficacy.

METHODS

Herein, we developed a proximal renal tubule-targeting gene delivery system based on alternative copolymer (PS) of sorbitol and polyethyleneimine (PEI), modified with vimentin-specific chitobionic acid (CA), producing PS-conjugated CA (PSC) for targeting toward vimentin-expressing cells in the kidneys. In vitro studies were used to determine cell viability, transfection efficiency, serum influence, and specific uptake in the human proximal renal tubular epithelial cell line (HK-2). Finally, the targeting efficiency of the prepared PSC gene carriers was checked in a murine model of Alport syndrome.

RESULTS

Our results suggested that the prepared polyplex showed low cytotoxicity, enhanced transfection efficiency, specific uptake toward HK-2 cells, and excellent targeting efficiency toward the kidneys.

CONCLUSION

Collectively, from these results it can be inferred that the PSC can be further evaluated as a potential gene carrier for the kidney-targeted delivery of therapeutic genes for treating diseases.

Venous thromboembolism and severe hypernatremia in a patient with lithium-induced nephrogenic diabetes insipidus and acute kidney injury: a case report

We report a case of thromboembolism in a patient with hypernatremia resulting from lithiuminduced nephrogenic diabetes insipidus (NDI). A 49-year-old female patient on chronic lithium therapy due to bipolar disorder was transferred to the emergency department with signs of dehydration, altered mental status, and increased oxygen demand. She was admitted to a local psychiatric clinic first because of an exacerbation of a manic episode. When she was transferred to our clinic, her blood pressure was 130/80 mmHg, she was tachycardic (110 beats/min), had tachypnea (24 breaths/min), normal body temperature (36.5 ℃), and an oxygen saturation of 94% via a face mask (10 L/min). Laboratory results showed hypertonic hypernatremia (osmolality, 363 mOsm/kg; sodium, 171 mEq/L), low urine osmolality (osmolality, 231 mOsm/kg), and normal urine sodium (Na, 63 mEq/L). Her serum lithium concentration was above the therapeutic range (1.52 mmol/L). An increase in cardiac markers and changes in electrocardiogram were detected; therefore, echocardiography was performed, which showed right ventricular dysfunction and small left ventricular chamber size. Computed tomography of the chest and lower extremities showed pulmonary thromboembolism (PTE) and deep venous thrombosis (DVT). She was treated with hypotonic fluid to correct hypernatremia and intravenous heparin for thromboembolism. The size of the thromboembolism decreased, and hypernatremia was corrected. She was discharged with a direct oral anticoagulant (DOAC). Here, we report a case of severe hypernatremia and venous thromboembolism in lithium-induced NDI.

Predictive Model for High Coronary Artery Calcium Score in Young Patients with Non-Dialysis Chronic Kidney Disease

Cardiovascular disease is a major complication of chronic kidney disease. The coronary artery calcium (CAC) score is a surrogate marker for the risk of coronary artery disease. The purpose of this study is to predict outcomes for non-dialysis chronic kidney disease patients under the age of 60 with high CAC scores using machine learning techniques. We developed the predictive models with a chronic kidney disease representative cohort, the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD). We divided the cohort into a training dataset (70%) and a validation dataset (30%). The test dataset incorporated an external dataset of patients that were not included in the KNOW-CKD cohort. Support vector machine, random forest, XGboost, logistic regression, and multi-perceptron neural network models were used in the predictive models. We evaluated the model’s performance using the area under the receiver operating characteristic (AUROC) curve. Shapley additive explanation values were applied to select the important features. The random forest model showed the best predictive performance (AUROC 0.87) and there was a statistically significant difference between the traditional logistic regression model and the test dataset. This study will help identify patients at high risk of cardiovascular complications in young chronic kidney disease and establish individualized treatment strategies.

Association of Urinary Potassium Excretion with Blood Pressure Variability and Cardiovascular Outcomes in Patients with Pre-Dialysis Chronic Kidney Disease

Dietary potassium intake is a dilemma in patients with chronic kidney disease (CKD). We investigated the association of urine potassium excretion, a surrogate for dietary potassium intake, with blood pressure variability (BPV) and cardiovascular (CV) outcomes in patients with pre-dialysis CKD. A total of 1860 participants from a cohort of pre-dialysis CKD (KNOW-CKD) patients were divided into the quartiles by spot urine potassium-to-creatinine ratio. The first quartile (26.423 ± 5.731 mmol/gCr) was defined as low urine potassium excretion. Multivariate linear regression analyses revealed an independent association of low urine potassium excretion with high BPV (adjusted β coefficient 1.163, 95% confidence interval 0.424 to 1.901). Cox regression analyses demonstrated that, compared to high urine potassium excretion, low urine potassium excretion is associated with increased risk of CV events (adjusted hazard ratio 2.502, 95% confidence interval 1.162 to 5.387) but not with all-cause mortality. In conclusion, low urine potassium excretion is associated with high BPV and increased risk of CV events in patients with pre-dialysis CKD. The restriction of dietary potassium intake should be individualized in patients with pre-dialysis CKD.

Anti-fibrotic effect of 6-bromo-indirubin-3'-oxime (6-BIO) via regulation of activator protein-1 (AP-1) and specificity protein-1 (SP-1) transcription factors in kidney cells

PAI-1 and CTGF are overexpressed in kidney diseases and cause fibrosis of the lungs, liver, and kidneys. We used a rat model of unilateral ureteral obstruction (UUO) to investigate whether 6-BIO, a glycogen synthase kinase-3β inhibitor, attenuated fibrosis by inhibiting PAI-1 and CTGF in vivo. Additionally, TGFβ-induced cellular fibrosis was observed in vitro using the human kidney proximal tubular epithelial cells (HK-2), and rat interstitial fibroblasts (NRK49F). Expression of fibrosis-related proteins and signaling molecules such as PAI-1, CTGF, TGFβ, αSMA, SMAD, and MAPK were determined in HK-2 and NRK49F cells using immunoblotting. To identify the transcription factors that regulate the expression of PAI-1 and CTGF the promoter activities of AP-1 and SP-1 were analyzed using luciferase assays. Confocal microscopy was used to observe the co-localization of AP-1 and SP-1 to PAI-1 and CTGF. Expression of PAI-1, CTGF, TGFβ, and α-SMA increased in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Furthermore, UUO and TGFβ treatment induced the activation of P-SMAD2/3, SMAD4, P-ERK 1/2, P-P38, and P-JNK MAPK signaling pathways. PAI-1, CTGF, AP-1 and SP-1 promoter activity increased in response to TGFβ treatment. However, treatment with 6-BIO decreased the expression of proteins and signaling pathways associated with fibrosis in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Moreover, 6-BIO treatment attenuated the expression of PAI-1 and CTGF as well as the promoter activities of AP-1 and SP-1, thereby regulating the SMAD and MAPK signaling pathways, and subsequently exerting anti-fibrotic effects on kidney cells.

Hypertension as a risk factor for retinal vein occlusion in menopausal women: A nationwide Korean population-based study

Retinal vein occlusion (RVO) is an important cause of blindness. Hypertension is a well-known risk factor for RVO. Although the prevalence of hypertension increases in women after menopause, the relationship between blood pressure and RVO in women before and after menopause has not been studied in detail.We retrospectively analyzed 2,619,206 patients from the Korean National Health Insurance System database. A Cox proportional hazard regression model was used to evaluate the independent association between blood pressure and the risk of RVO development and identify differences between premenopausal and postmenopausal women.The incidence of RVO was higher among postmenopausal women than in premenopausal women. In the model adjusted for socioeconomic and clinical variables, there was an association between blood pressure and RVO development in premenopausal and postmenopausal women; however, this was stronger than premenopausal women.Both systolic and diastolic blood pressure are associated with an increased risk of RVO, and their effects are more potent in premenopausal women than postmenopausal women. Thus, comprehensive management of hypertension in premenopausal women is essential to reduce the risk of RVO.

Renoprotective Effects of Maslinic Acid on Experimental Renal Fibrosis in Unilateral Ureteral Obstruction Model via Targeting MyD88

Maslinic acid (MA), also named crategolic acid, is a pentacyclic triterpene extracted from fruits and vegetables. Although various beneficial pharmacological effects of MA have been revealed, its effect on renal fibrosis remains unclear. This study was designed to clarify whether MA could attenuate renal fibrosis and determine the putative underlying molecular mechanisms. We demonstrated that MA-treated mice with unilateral ureteral obstruction (UUO) developed a histological injury of low severity and exhibited downregulated expression of fibrotic markers, including α-smooth muscle actin (α-SMA), vimentin, and fibronectin by 38, 44 and 40%, and upregulated expression of E-cadherin by 70% as compared with untreated UUO mice. Moreover, MA treatment restored the expression levels of α-SMA, connective tissue growth factor, and vimentin to 10, 7.8 and 38% of those induced by transforming growth factor (TGF)-β in NRK49F cells. MA decreased expression of Smad2/3 phosphorylation and Smad4 in UUO kidneys and TGF-β treated NRK49F cells (p < 0.05, respectively). Notably, MA specifically interferes with MyD88, an adaptor protein, thereby mitigating Smad4 nuclear expression (p < 0.01 compared to TGF-β treated group) and ameliorating renal fibrotic changes (p < 0.01 for each fibrotic markers compared to TGF-β induced cells). In addition, in the UUO model and lipopolysaccharide-induced NRK49F cells, MA treatment decreased the expression of IL-1β, TGF-α and MCP-1, ICAM-1, associated with the suppression of NF-κB signaling. These findings suggest that MA is a potential agent that can reduce renal interstitial fibrosis, to some extent, via targeting TGF-β/Smad and MyD88 signaling.

Hyperuricemia is a risk factor for the progression to end-stage renal disease in minimal change disease

BACKGROUND

Minimal change disease (MCD) is one of the most common causes of nephrotic syndrome worldwide. Hyperuricemia increases the end-stage renal disease (ESRD) risk in glomerulonephritis. In this study, we aimed to determine the effect of high serum uric acid levels on the progression to ESRD in MCD.

METHODS

A total of 800 patients diagnosed with MCD by kidney biopsy were retrospectively analyzed. We determined the relationship of hyperuricemia with the progression to ESRD in MCD using the Cox proportional hazard model and Kaplan-Meier survival analysis. The primary outcome was defined as the initiation of dialysis or kidney transplantation.

RESULTS

A total of 42 patients (5.3%) progressed to ESRD during the follow-up period. In the restricted cubic spline curve, serum uric acid levels exhibited a positive correlation with ESRD progression in patients with MCD. In the fully adjusted model, the risk of MCD progression increased by 29% for every 1 mg/dL increase in the baseline serum uric acid level (hazard ratio [HR], 1.29; 95% confidence interval [CI], 1.09-1.54; p = 0.004). Falling into the high uric acid group (serum uric acid level > 7 mg/dL in men and > 6 mg/dL in women) was also a risk factor for progression of MCD to ESRD (HR, 3.40; 95% CI, 1.59-7.31; p < 0.001).

CONCLUSION

Our study shows that hyperuricemia is an independent risk factor for the progression to ESRD in patients with MCD.

Cumulative hypertension burden and risk of end-stage renal disease

Hypertension is the leading risk factor for end-stage renal disease (ESRD). However, the association between sustained exposure to increased blood pressure (BP) and ESRD is not well established. This study investigated whether the cumulative hypertension burden is a substantial risk factor for ESRD. The incidence of ESRD among 2,144,801 participants identified from the Korean National Health Insurance Service database who had documented BP assessment data in their annual health check-up data from between 2006 and 2010, was determined. Over a median follow-up of 7.2 years, ESRD was identified in 1758 participants. Hypertension burden was defined as the cumulative exposure to hypertension (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) during four consecutive follow-up periods and ranged from 0 to 4. The hypertension burden was as follows: 0 (n = 1,164,488), 77.6%; 1 (n = 292,377), 13.6%; 2 (n = 114,397), 5.3%; 3 (n = 52,671), 2.5%; and 4 (n = 20,886), 1.0%. Compared to the hypertension burden of 0, the adjusted hazard ratio for ESRD was 1.35, 1.54, 1.51, and 2.28 for hypertension burdens of 1, 2, 3, and 4, respectively. A positive dose-dependent relationship between hypertension burden and ESRD was found (P for interaction < 0.001). This association was maintained for sustained exposure to both systolic and diastolic hypertension burden. In conclusion, hypertension burden increases the risk of ESRD. Our study underlines the usefulness of a new assessment of the hypertension burden over a certain period for predicting the risk of ESRD in a large population-based cohort.

Risk of Kidney Failure in Patients With Cancer: A South Korean Population-Based Cohort Study

RATIONALE & OBJECTIVE

Reduced kidney function is associated with an increased risk of cancer; however, it is unclear if cancer increases the risk of kidney failure with replacement therapy (KFRT). We assessed the risk of KFRT among patients with various types of cancer collectively and with specific types of cancer.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING & PARTICIPANTS

A total of 2,473,095 participants with (n = 824,365) or without (n = 1,648,730) cancer registered in the Korean National Health Insurance Service database.

PREDICTORS

Cancer and cancer subtypes defined using International Classification of Diseases, 10th Revision, Clinical Modification, codes.

OUTCOMES

Primary outcome was KFRT defined as the initiation of hemodialysis or peritoneal dialysis or kidney transplantation.

ANALYTICAL APPROACH

For each patient with cancer, 2 controls matched for age, sex, estimated glomerular filtration rate, diabetes, and hypertension were included. To address the competing risk of death, a competing risk survival analysis was conducted using the Fine and Gray method.

RESULTS

Occurrence of KFRT was higher in patients with cancer than in controls without cancer (incidence rates of 1.07 vs 0.51 cases per 1,000 person-years). Competing risk analysis showed that cancer was significantly associated with an increased risk of KFRT after adjusting for other potential predictors (adjusted hazard ratio, 2.29 [95% CI, 2.20-2.39]). Multiple myeloma, leukemia, lymphoma, and kidney, ovarian, and liver cancer were most significantly associated with an increased KFRT risk, with multiple myeloma conferring the highest risk across age and sex groups. All subgroups of patients with cancer (based on age, sex, smoking, alcohol, exercise, obesity, and comorbid conditions) exhibited a higher risk of KFRT.

LIMITATIONS

Causal association between cancer and kidney outcomes could not be confirmed.

CONCLUSIONS

Patients with cancer, particularly those with multiple myeloma, exhibited an increased risk of KFRT after accounting for the competing risk of death.

Osmotic Demyelination Syndrome Associated with Hypernatremia Caused by Lactulose Enema in a Patient with Chronic Alcoholism

A 44-year-old man with chronic alcoholism presented with seizure and loss of consciousness. He was diagnosed with alcoholic hepatic encephalopathy, and his neurologic symptoms recovered after lactulose enema treatment. His initial serum sodium level was 141mEq/L. However, his mental state became confused after treatment with lactulose enema for five days, and his serum sodium level increased to 178mEq/L. After five days of gradual correction of serum sodium level from 178mEq/L to 140mEq/L, the patient's mental state recovered, but motor weakness in both limbs remained. Therefore, magnetic resonance imaging of the brain was performed. T2-weighted brain images showed bilateral symmetrical hyperintensities in the central pons, basal ganglia, thalami, hippocampi and unci, which were consistent with central pontine and extrapontine myelinolysis. We report a rare case of osmotic demyelination syndrome that occurred as a result of a rapid increase from a normal sodium level to hypernatremia caused by lactulose enema administered to treat alcoholic hepatic encephalopathy.

An anastomosing hemangioma mimicking a renal cell carcinoma in a kidney transplant recipient: a case report

Background

Although anastomosing hemangiomas are very rare and benign vascular neoplasms, these tumors are more common among patients with end-stage kidney disease. Incidental finding of these tumors in the kidney or adrenal gland has been reported. Herein, we describe a case in which an anastomosing hemangioma was misdiagnosed as a renal cell carcinoma before kidney transplant.

Case presentation

A 35-year-old woman with lupus nephritis was admitted to our emergency department for suspected uremic symptoms of nausea and general weakness. She had received hemodialysis due to end-stage kidney disease, and a living-donor kidney transplantation from her father was planned. On pre-operative contrast-enhanced computed tomography and magnetic resonance imaging, a 1.7 cm renal cell carcinoma was observed in the right kidney. On staining after radical nephrectomy, irregularly shaped vascular spaces of various sizes were observed, with these spaces having an anastomosing pattern. As the findings of the anastomosing hemangioma are similar to those of a renal cell carcinoma on imaging, histology examination was necessary to confirm the diagnosis of anastomosing hemangioma and to prevent delay in listing for kidney transplantation. Good kidney function was achieved after transplantation, with no tumor recurrence.

Conclusion

Our case underlines the importance for prompt surgical resection of an enhancing renal mass to confirm diagnosis in patients scheduled for kidney transplantation to avoid any delay.

Blood pressure prior to percutaneous coronary intervention is associated with the risk of end-stage renal disease: a nationwide population based-cohort study

Background

Hypertension is the most important modifiable risk factor for mortality and morbidity in chronic kidney disease and coronary artery syndrome. The effect of hypertension prior to percutaneous coronary intervention (PCI) on the development of end-stage renal disease (ESRD) is unknown.

Methods

We used nationally representative data from the Korean National Health Insurance System-140,164 subjects were enrolled during 2010-2015; they were free of ESRD at enrolment, underwent PCI, and were followed up until 2017. Blood pressure (BP) was measured within at least 2 years prior to PCI. The primary outcome was the development of ESRD.

Results

During a median follow-up of 5.4 years, 2,082 participants (1.5%) developed ESRD. The highest systolic BP group (>160 mmHg) showed a higher hazard ratio (3.69; 95% confidence interval, 2.61-5.23) than the reference group (110-119 mmHg). Similar results were observed in the highest diastolic BP group (>120 mmHg), which showed a higher hazard ratio than the reference group (70-79 mmHg). However, ESRD risk showed a J-shaped relationship with baseline systolic and diastolic BP at 113 and 74 mmHg in diabetes mellitus subgroup, respectively, after adjustment for potential confounders.

Conclusion

Our study showed that a high systolic or diastolic BP prior to PCI was independently associated with an increased incidence of ESRD.

Retroperitoneal emphysema caused by a renal abscess: a case report

We report a case of retroperitoneal emphysema caused by a renal abscess. A 45-year-old man with underlying type 2 diabetes mellitus visited the emergency department with right flank pain and a fever. On physical examination, right costovertebral tenderness in the ipsilateral flank was noted. Leukocytosis and high inflammatory marker levels were observed. Urinalysis showed pyuria and glucosuria. Urine culture was positive for Streptococcus agalactiae. A computed tomography scan of the abdomen showed a focal, lowattenuation lesion in the right kidney with a 3 cm, exophytic, high-attenuation lesion in the right kidney upper pole and gas-containing fluid collection within the retroperitoneal space. The diagnosis was retroperitoneal emphysema caused by a renal abscess. As the vital signs were stable and the patient refused puncture, we decided on a course of antibiotics alone with follow-up without percutaneous drainage or surgery. The patient improved without any complications. This is a rare case of a renal abscess penetrating the renal fascia and progressing to a posterior paranephric emphysema. The patient was treated with antibiotics alone and cured successfully. Early diagnosis and proper treatment are needed, and percutaneous drainage or urgent surgery would be beneficial for such cases depending on the patient's condition.

Effect of urinary angiotensinogen and high-salt diet on blood pressure in patients with chronic kidney disease: results from the Korean Cohort Study for Outcome in Patients with Chronic Kidney Disease (KNOW-CKD)

BACKGROUND/AIMS

This study aimed to investigate whether urinary angiotensinogen (UAGT) excretion was associated with elevated blood pressure in patients with chronic kidney disease (CKD) and to evaluate the relationship among blood pressure, intra-renal renin-angiotensin system (RAS) activity, and dietary sodium in patients with CKD.

METHODS

Participants from the Korean Cohort Study for Outcome in Patients with Chronic Kidney Disease (KNOW-CKD) were included. Of the total cohort of 2,238 individuals with CKD, we included 1,955 participants who underwent complete 24-hour urinary sodium (24-hour UNa) analysis. They were categorized into three groups according to three tertiles of their 24-hour UNa, reflecting daily salt intake. To measure intra-renal RAS activity, the UAGT excretion was assayed with an enzyme-linked immunosorbent assay.

RESULTS

Elevated 24-hour UNa levels, logarithm of UAGT-to-creatinine ratio (UAGT/Cr), increased waist-to-hip ratio, and decreased estimated glomerular filtration rate were the risk factors for increased systolic blood pressure. Systolic blood pressure showed a positive correlation with 24-hour UNa levels and logarithm of UAGT/Cr.

CONCLUSION

UAGT and urinary sodium excretion are independent determinants of systolic blood pressure in patients with CKD. These findings suggest that increased systolic blood pressure in CKD patients is associated with both increased dietary sodium levels and intra-renal RAS activity. The risk of elevated systolic blood pressure in the 3rd tertile of both the UAGT/Cr and 24-hour UNa groups was about 2.3 times higher than that in the reference group.

Glycol chitosan-based tacrolimus-loaded nanomicelle therapy ameliorates lupus nephritis

Background

Recently, we developed hydrophobically modified glycol chitosan (HGC) nanomicelles loaded with tacrolimus (TAC) (HGC-TAC) for the targeted renal delivery of TAC. Herein, we determined whether the administration of the HGC-TAC nanomicelles decreases kidney injury in a model of lupus nephritis. Lupus-prone female MRL/lpr mice were randomly assigned into three groups that received intravenous administration of either vehicle control, an equivalent dose of TAC, or HGC-TAC (0.5 mg/kg TAC) weekly for 8 weeks. Age-matched MRL/MpJ mice without Fas^lpr mutation were also treated with HGC vehicle and used as healthy controls.

Results

Weekly intravenous treatment with HGC-TAC significantly reduced genetically attributable lupus activity in lupus nephritis-positive mice. In addition, HGC-TAC treatment mitigated renal dysfunction, proteinuria, and histological injury, including glomerular proliferative lesions and tubulointerstitial infiltration. Furthermore, HGC-TAC treatment reduced renal inflammation and inflammatory gene expression and ameliorated increased apoptosis and glomerular fibrosis. Moreover, HGC-TAC administration regulated renal injury via the TGF-β1/MAPK/NF-κB signaling pathway. These renoprotective effects of HGC-TAC treatment were more potent in lupus mice compared to those of TAC treatment alone.

Conclusion

Our study indicates that weekly treatment with the HGC-TAC nanomicelles reduces kidney injury resulting from lupus nephritis by preventing inflammation, fibrosis, and apoptosis. This advantage of a new therapeutic modality using kidney-targeted HGC-TAC nanocarriers may improve drug adherence and provide treatment efficacy in lupus nephritis mice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00857-w.

Trends in the incidence and prevalence of end-stage renal disease with hemodialysis in entire Korean population: A nationwide population-based study

Data on the overall epidemiology and temporal trends of end-stage renal disease (ESRD) requiring hemodialysis in Korea are scarce. We aimed to estimate the prevalence and incidence of ESRD requiring hemodialysis in Korea between 2002 and 2017.Using the National Health Insurance Service database, we analyzed data from the entire Korean population between 2002 and 2017. Hemodialysis patients were identified using rare incurable disease codes (V001) or prescription of medical fee codes of hemodialysis (O7020 and O7021). We only included patients who had been maintained on hemodialysis for more than 90 days from the date of dialysis initiation, to exclude patients who required short-term dialysis for acute kidney injury, conversion to peritoneal dialysis, or kidney transplantation.During the 16-year follow-up, the number of hemodialysis patients in Korea has steadily increased from 11,215 in 2002 to 67,486 in 2017. The mean age of these patients has gradually increased from 55.57 ± 13.31 years in 2002 to 62.13 ± 13.23 years in 2017. In 2017, the crude prevalence rate of hemodialysis was 1303.4 per million population. Overall, the number of men tended to be somewhat higher than that of women, and the proportion of men increased slightly from 55.56% in 2002 to 58.45% in 2017. The proportion of diabetic patients increased rapidly from 23.84% to 47.84%, and the percentage of dyslipidemic patients rose from 18.9% to 86.7%. The number of incident hemodialysis patients increased significantly from 4406 in 2003 to 12,134 in 2014, and then decreased to 8090 in 2017. In the incident cases of hemodialysis, the observed increase in the proportion of male patients and in diabetes and dyslipidemia were similar to that of prevalent patients. The more recent era of hemodialysis initiation, the better 5-year survival rates were observed.The prevalence and incidence of hemodialysis in Korea gradually increased between 2002 and 2017. The proportion of men, and patients with diabetes and dyslipidemia requiring hemodialysis also increased continuously. The survival rate of hemodialysis patients was gradually improving. These findings may serve as a reference for future epidemiological studies on hemodialysis in Korea.

Chronic Kidney Disease Risk of Isolated Systolic or Diastolic Hypertension in Young Adults: A Nationwide Sample Based-Cohort Study

Background

Hypertension among young adults is common. However, the effect of isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), or systolic and diastolic hypertension (SDH) among young adults on chronic kidney disease (CKD) development is unknown.

Methods and Results

From a nationwide health screening database, we included 3 030 884 participants aged 20 to 39 years who were not taking antihypertensives at baseline examination in 2009 to 2010. Participants were categorized as having normal blood pressure (BP), elevated BP, stage 1 IDH, stage 1 ISH, stage 1 SDH, stage 2 IDH, stage 2 ISH, and stage 2 SDH. The primary outcome was incident CKD. A total of 5853 (0.19%) CKD events occurred. With normal BP as the reference, multivariable‐adjusted hazard ratios (HRs) (95% CIs) for CKD were 1.14 (95% CI, 1.04–1.26), elevated BP; 1.19 (95% CI, 1.10–1.28), stage 1 IDH; 1.24 (95% CI, 1.08–1.42), stage 1 ISH; 1.39 (95% CI, 1.28–1.51), stage 1 SDH; 1.88 (95% CI, 1.63–2.16), stage 2 IDH; 1.84 (95% CI, 1.54–2.19), stage 2 ISH; 2.70 (95% CI, 2.44–2.98), stage 2 SDH. The HRs for CKD were attenuated in the patients who were antihypertensive and began medication within 1 year of medical checkup than in those without antihypertensives.

Conclusions

Among Korean young adults, those with elevated BP, stage 1 IDH, stage 1 ISH, stage 1 SDH, stage 2 IDH, stage 2 ISH, and stage 2 SDH were associated with a higher CKD risk than those with normal BP. The CKD risk in ISH and IDH groups was similar but lower than that in the SDH group. Antihypertensives attenuated the risk of CKD in young adults with hypertension.