Lactobacillus acidophilus KBL409 protects against kidney injury via improving mitochondrial function with chronic kidney disease.

PURPOSE: Recent advances have led to greater recognition of the role of mitochondrial dysfunction in the pathogenesis of chronic kidney disease (CKD). There has been evidence that CKD is also associated with dysbiosis. Here, we aimed to evaluate whether probiotic supplements can have protective effects against kidney injury via improving mitochondrial function. METHODS: An animal model of CKD was induced by feeding C57BL/6 mice a diet containing 0.2% adenine. KBL409, a strain of Lactobacillus acidophilus, was administered via oral gavage at a dose of 1 × 109 CFU daily. To clarify the underlying mechanisms by which probiotics exert protective effects on mitochondria in CKD, primary mouse tubular epithelial cells stimulated with TGF-ß and p-cresyl sulfate were administered with butyrate. RESULTS: In CKD mice, PGC-1α and AMPK, key mitochondrial energy metabolism regulators, were down-regulated. In addition, mitochondrial dynamics shifted toward fission, the number of fragmented cristae increased, and mitochondrial mass decreased. These alterations were restored by KBL409 administration. KBL409 supplementation also improved defects in fatty acid oxidation and glycolysis and restored the suppressed enzyme levels involved in TCA cycle. Accordingly, there was a concomitant improvement in mitochondrial respiration and ATP production assessed by mitochondrial function assay. These favorable effects of KBL409 on mitochondria ultimately decreased kidney fibrosis in CKD mice. In vitro analyses with butyrate recapitulated the findings of animal study. CONCLUSIONS: This study demonstrates that administration of the probiotic Lactobacillus acidophilus KBL409 protects against kidney injury via improving mitochondrial function.

MicroRNA-5010-5p ameliorates high-glucose induced inflammation in renal tubular epithelial cells by modulating the expression of PPP2R2D.

INTRODUCTION: We previously reported the significant upregulation of eight circulating exosomal microRNAs (miRNAs) in patients with diabetic kidney disease (DKD). However, their specific roles and molecular mechanisms in the kidney remain unknown. Among the eight miRNAs, we evaluated the effects of miR-5010-5p on renal tubular epithelial cells under diabetic conditions in this study. RESEARCH DESIGN AND METHODS: We transfected the renal tubular epithelial cell line, HK-2, with an miR-5010-5p mimic using recombinant plasmids. The target gene of hsa-miR-5010-5p was identified using a dual-luciferase assay. Cell viability was assessed via the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Moreover, mRNA and protein expression levels were determined via real-time PCR and western blotting, respectively. RESULTS: High glucose levels did not significantly affect the intracellular expression of miR-5010-5p in HK-2 cells. Transfection of the miR-5010-5p mimic caused no change in cell viability. However, miR-5010-5p-transfected HK-2 cells exhibited significantly decreased expression levels of inflammatory cytokines, such as the monocyte chemoattractant protein-1, interleukin-1ß, and tumor necrosis factor-ɑ, under high-glucose conditions. These changes were accompanied by the restored expression of phosphorylated AMP-activated protein kinase (AMPK) and decreased phosphorylation of nuclear factor-kappa B. Dual-luciferase assay revealed that miR-5010-5p targeted the gene, protein phosphatase 2 regulatory subunit B delta (PPP2R2D), a subunit of protein phosphatase 2A, which modulates AMPK phosphorylation. CONCLUSIONS: Our findings suggest that increased miR-5010-5p expression reduces high glucose-induced inflammatory responses in renal tubular epithelial cells via the regulation of the target gene, PPP2R2D, which modulates AMPK phosphorylation. Therefore, miR-5010-5p may be a promising therapeutic target for DKD.

Dietary cholesterol intake is not associated with the development of chronic kidney disease: Results from two Korean cohort studies.

BACKGROUND AND AIMS: Although dyslipidemia is a major risk factor for chronic kidney disease (CKD), the relationship between dietary cholesterol and CKD remains unknown. We investigated the association between cholesterol intake and CKD risk. METHODS AND RESULTS: The Korea National Health and Nutrition Examination Survey (KNHANES) 2019-2021 (n = 13,769) and the Korean Genome and Epidemiology Study (KoGES) (n = 9225) data were used for this study. Cholesterol intake was assessed using a 24-h recall food frequency questionnaire, and participants were categorized into three groups (T1, T2, and T3) based on cholesterol intake. Primary outcomes were prevalence and incidence of CKD. Higher cholesterol intake was modestly associated with increased serum levels of total, low-density lipoprotein, and high-density lipoprotein cholesterol in the KNHANES. However, we found no significant association between cholesterol intake and CKD prevalence in the KNHANES, regardless of a history of hypercholesterolemia. In the KoGES, during a median follow-up of 11.4 years, cholesterol intake was not associated with incident CKD in participants without hypercholesterolemia (hazard ratio [HR] per 10 mg increase, 1.00; 95 % confidence interval [CI], 0.99-1.01) and in those with hypercholesterolemia (HR, 1.01; 95 % CI, 0.98-1.04). Egg consumption also showed no significant association with the risk of incident CKD. Additionally, cholesterol intake had no significant interaction on the relationships between serum cholesterol levels and incident CKD. CONCLUSION: Although cholesterol intake was associated with increased serum cholesterol levels, it was not associated with CKD prevalence and incidence. Our findings suggest that reducing cholesterol intake alone may not be sufficient to prevent CKD.

Proteinuria, measured or estimated albuminuria for risk prediction in patients with chronic kidney disease?

BACKGROUND: Although albuminuria is the gold standard for defining chronic kidney disease (CKD), total proteinuria has also been widely used in real-world clinical practice. Moreover, the superiority of the prognostic performance of albuminuria over proteinuria in patients with CKD remains inconclusive. Therefore, we aimed to compare the predictive performances of albuminuria and proteinuria in these patients. METHODS: From the Korean Cohort Study for Outcome in Patients with CKD we included 2099 patients diagnosed with CKD grades 1-5 who did not require kidney replacement therapy. We measured the spot urine albumin:creatinine ratio (mACR) and protein:creatinine ratio (PCR) and estimated the ACR (eACR) using the PCR. Kidney failure risk equation (KFRE) scores were calculated using the mACR, PCR and eACR. The primary outcome was the 5-year risk of kidney failure with replacement therapy (KFRT). RESULTS: The eACR significantly underestimated mACR in patients with low albuminuria levels. The time-dependent area under the receiver operating characteristics curve showed excellent predictive performance for all KFRE scores from the mACR, PCR and eACR. However, eACR was inferior to mACR based on the continuous net reclassification index (cNRI) and integrated discrimination improvement index (IDI) in all CKD cause groups, except for the group with an unclassified aetiology. Moreover, the cNRI and IDI statistics indicated that both eACR and PCR were inferior to mACR in patients with low albuminuria (<30 mg/g). Conversely, the predictive performance of PCR was superior in severe albuminuria and nephrotic-range proteinuria, in which the IDI and cNRI of the PCR were greater than those of the mACR. CONCLUSIONS: The mACR, eACR and PCR showed excellent performance in predicting KFRT in patients with CKD. However, eACR was inferior to mACR in patients with low albuminuria, indicating that measuring rather than estimating albuminuria is preferred for these patients.

Effect of low-density lipoprotein level and mortality in older incident statin-naïve hemodialysis patients.

BACKGROUND: This study aimed to analyze low-density lipoprotein cholesterol (LDL-C) levels and their relationship with mortality in order to identify the appropriate lipid profile for older Korean hemodialysis patients. METHODS: We enrolled a total of 2,732 incident hemodialysis patients aged > 70 years from a retrospective cohort of the Korean Society of Geriatric Nephrology from 2010 Jan to 2017 Dec, which included 17 academic hospitals in South Korea. Of these patients, 1,709 were statin-naïve, and 1,014 were analyzed after excluding those with missing LDL-C level data. We used multivariate Cox regression analysis to select risk factors from 20 clinical variables among the LDL-C groups. RESULTS: The mean age of the entire patient population was 78 years, with no significant differences in age between quartiles Q1 to Q4. However, the proportion of males decreased as the quartiles progressed towards Q4 (p < 0.001). The multivariate Cox regression analysis, which included all participants, showed that low LDL-C levels were associated with all-cause mortality. In the final model, compared to Q1, the hazard ratios (95% confidence interval) were 0.77 (0.620-0.972; p = 0.027), 0.85 (0.676-1.069; p = 0.166), and 0.65 (0.519-0.824; p < 0.001) for Q2, Q3, and Q4, respectively, after adjusting for covariates, such as conventional and age-specific risk factors. The final model demonstrated that all-cause mortality increased as LDL-C levels decreased, as confirmed by a restrictive cubic spline plot. CONCLUSIONS: In older hemodialysis patients who had not previously received dyslipidemia treatment, elevated LDL-C levels were not associated with increased all-cause mortality. Intriguingly, lower LDL-C levels appear to be associated with an unfavorable effect on all-cause mortality among high-risk hemodialysis patients.

Predictive performance of the new race-free Chronic Kidney Disease Epidemiology Collaboration equations for kidney outcome in Korean patients with chronic kidney disease.

BACKGROUND: The new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations without a race coefficient have gained recognition across the United States. We aimed to test whether these new equations performed well in Korean patients with chronic kidney disease (CKD). METHODS: This study included 2,149 patients with CKD G1-G5 without kidney replacement therapy from the Korean Cohort Study for Outcome in Patients with CKD (KNOW-CKD). The estimated glomerular filtration rate (eGFR) was calculated using the new CKD-EPI equations with serum creatinine and cystatin C. The primary outcome was 5-year risk of kidney failure with replacement therapy (KFRT). RESULTS: When we adopted the new creatinine equation [eGFRcr (NEW)], 81 patients (23.1%) with CKD G3a based on the current creatinine equation (eGFRcr) were reclassified as CKD G2. Accordingly, the number of patients with eGFR of <60 mL/min/1.73 m2 decreased from 1,393 (64.8%) to 1,312 (61.1%). The time-dependent area under the receiver operating characteristic curve for 5-year KFRT risk was comparable between the eGFRcr (NEW) (0.941; 95% confidence interval [CI], 0.922-0.960) and eGFRcr (0.941; 95% CI, 0.922-0.961). The eGFRcr (NEW) showed slightly better discrimination and reclassification than the eGFRcr. However, the new creatinine and cystatin C equation [eGFRcr-cys (NEW)] performed similarly to the current creatinine and cystatin C equation. Furthermore, eGFRcr-cys (NEW) did not show better performance for KFRT risk than eGFRcr (NEW). CONCLUSION: Both the current and the new CKD-EPI equations showed excellent predictive performance for 5-year KFRT risk in Korean patients with CKD. These new equations need to be further tested for other clinical outcomes in Koreans.

Association between abdominal perivascular adipose tissue quantity and quality assessed by CT and cardiometabolic risk.

BACKGROUND & AIMS: Changes in the perivascular adipose tissue (PVAT) are associated with the risk of metabolic syndrome (MetS). We hypothesized that the quantity and quality of PVAT measured by computed tomography (CT) are associated with cardiometabolic risk. METHODS: This study analyzed the data of 505 participants (men, 72.7%) who underwent general health checkups, including abdominal and pelvic CT. We measured the volume and fat attenuation index (FAI) of the abdominal periaortic (APA) and renal sinus (RS) adipose tissues. Participants were categorized into three groups according to the number of MetS components they had based on the modified ATP III criteria (0, 1-2, and ≥3). RESULTS: Moving stepwise from the no MetS component group to the 1-2 components group to the ≥3 components group, all PVAT volumes increased and all PVAT FAIs decreased consistently. Greater PVAT volume was independently associated with greater prevalence of MetS components in the ≥3 components group (P = 0.002 for right RS, P = 0.027 for left RS, and P = 0.001 for APA), whereas lower FAI in all PVATs was associated with greater prevalence of MetS components in the 1-2 components group after adjusting for the corresponding adipose tissue volumes (P = 0.007 for right RS, P = 0.002 for left RS, and P = 0.001 for APA). CONCLUSION: Higher abdominal PVAT volume was independently associated with prevalent MetS. Moreover, lower abdominal PVAT FAI was associated with mild metabolic derangement. Image-based assessment of abdominal PVAT may be a potential biomarker for cardiometabolic risk.

Association of glomerular hyperfiltration with carotid artery plaque in the general population.

BACKGROUND AND AIMS: Glomerular hyperfiltration (GHF) is a hemodynamic change of the kidney as an adaptive response to nephron loss. Although GHF is associated with metabolic risk factors and cardiovascular disease (CVD), the mechanisms that explain these relationships remain largely unknown. This is partially caused by a non-unified definition of GHF based on pathophysiologic vascular changes. Thus, the objective of this study was to evaluate the association between various definitions of GHF and carotid plaque in a health checkup cohort. METHODS: A total of 4493 individuals without history of CVD who had carotid ultrasonography (USG) results available between January 2016 and June 2018 were enrolled. GHF was defined as >90th percentile of eGFR residuals after adjusting for confounding factors. Carotid plaque score was calculated based on carotid USG results. RESULTS: Of 4493 individuals (mean age, 52.3 ± 10.1 years; 3224 [71.8%] males), 449 subjects were included in the GHF group (mean eGFR, 107.0 ± 7.1 ml/min/1.73 m2) and 4044 subjects were included in the non-GHF group (mean eGFR, 92.5 ± 12.3 ml/min/1.73 m2). When the GHF group was compared to the non-GHF group, GHF was associated with the presence of significant carotid plaque (carotid plaque score ≥2) (adjusted OR: 1.46; 95% CI: 1.16 to 1.83; p = 0.001). GHF defined in this study showed higher sensitivity to the presence of carotid plaque than other definitions of GHF. CONCLUSIONS: GHF status was associated with risk of carotid plaque in individuals without history of CVD. Presence of subclinical carotid plaque was associated with risk of future CVD. Therefore, GHF based on creatinine could be a useful surrogate marker for surveillance of CVD in asymptomatic individuals.

Empagliflozin suppresses urinary mitochondrial DNA copy numbers and interleukin-1ß in type 2 diabetes patients.

Sodium-glucose co-transporter 2 (SGLT2) inhibitors improve cardiovascular and renal outcomes in type 2 diabetes mellitus (T2DM) patients. However, the mechanisms by which SGLT2 inhibitors improve the clinical outcomes remain elusive. We evaluated whether empagliflozin, an SGLT2 inhibitor, ameliorates mitochondrial dysfunction and inflammatory milieu of the kidneys in T2DM patients. We prospectively measured copy numbers of urinary and serum mitochondrial DNA (mtDNA) nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND-1) and cytochrome-c oxidase 3 (mtCOX-3) and urinary interleukin-1ß (IL-1ß) in healthy volunteers (n = 22), in SGLT2 inhibitor-naïve T2DM patients (n = 21) at baseline, and in T2DM patients after 3 months of treatment with empagliflozin (10 mg, n = 17 or 25 mg, n = 4). Both urinary mtDNA copy numbers and IL-1ß levels were higher in the T2DM group than in healthy volunteers. Baseline copy numbers of serum mtCOX-3 in the T2DM group were lower than those in healthy volunteers. Empagliflozin induced marked reduction in both urinary and serum mtND-1 and mtCOX-3 copy numbers, as well as in urinary IL-1ß. Empagliflozin could attenuate mitochondrial damage and inhibit inflammatory response in T2DM patients. This would explain the beneficial effects of SGLT2 inhibitors on cardiovascular and renal outcomes.

Serum creatinine to cystatin C ratio and clinical outcomes in adults with non-dialysis chronic kidney disease.

Background: Studies have suggested that the serum creatinine/cystatin C (Cr/CysC) ratio is a surrogate marker for muscle wasting is associated with adverse outcomes in several disease conditions. To clarify the utility of the Cr/CysC ratio as a prognostic marker in chronic kidney disease (CKD) we evaluated the association between the Cr/CysC ratio clinical outcomes in patients with non-dialysis CKD. Methods: This prospective observational cohort study included 1,966 participants of the KoreaN cohort study Outcomes in patients With CKD (KNOW-CKD). We evaluated associated factors with the serum Cr/CysC ratio and association between the serum Cr/CysC ratio and composite outcomes of all-cause death and cardiovascular events (CVEs). Results: The mean age was 54 ± 12 (SD) years and 61% were men. The mean serum Cr/CysC ratio was 10.97 ± 1.94 in men and 9.10 ± 1.77 in women. The Cr/CysC ratio correlated positively with urinary creatinine excretion, a marker of muscle mass. In the fully adjusted Cox proportional hazard model, the Cr/CysC ratio was associated with the occurrence of adverse outcomes through a median follow-up of 5.9 years [hazard ratio (HR) = 0.92, 95% confidence interval (CI) = 0.85-0.99 for the composite outcomes, HR = 0.87, 95% CI, 0.78 - 0.97 for all-cause death, and HR = 0.93; 95% CI, 0.84-1.04 for CVEs]. In subgroup analyses, there were interactions of the Cr/CysC ratio with age and sex for risk of the clinical outcomes, but not eGFR group. Conclusion: A higher Cr/CysC ratio is associated with a lower risk of the composite outcomes, especially all-cause mortality, even after adjusting for eGFR. These suggest that the Cr/CysC ratio is a useful prognostic marker in CKD.

Lactobacillus acidophilus KBL409 Reduces Kidney Fibrosis via Immune Modulatory Effects in Mice with Chronic Kidney Disease.

SCOPE: Intestinal dysbiosis has been reported to play an important role in the pathogenesis of various diseases, including chronic kidney disease (CKD). Here, to evaluate whether probiotic supplements can have protective effects against kidney injury in an animal model of CKD is aimed. METHODS AND RESULTS: An animal model of CKD is established by feeding C57BL/6 mice a diet containing 0.2% adenine. These model mice are administered Lactobacillus acidophilus KBL409 daily for 4 weeks. Features of adenine-induce CKD (Ade-CKD) mice, such as prominent kidney fibrosis and higher levels of serum creatinine and albuminuria are improved by administration of KBL409. Ade-CKD mice also exhibit a disrupted intestinal barrier and elevate levels of TNF-α, IL-6, and 8-hydroxy-2'-deoxyguanosine. These changes are attenuated by KBL409. Administration of KBL409 significantly reduces macrophage infiltration and promotes a switch to the M2 macrophage phenotype and increasing regulatory T cells. Notably, the NLRP3 inflammasome pathway is activated in the kidneys of Ade-CKD and decreases by KBL409. In primary kidney tubular epithelial cells treated with p-cresyl sulfate, short-chain fatty acids significantly increase M2 macrophage polarization factors and decrease profibrotic markers. CONCLUSIONS: These results demonstrate that supplementation with the probiotic KBL409 has beneficial immunomodulating effects and protects against kidney injury.

Executive summary of the Korean Society of Nephrology 2021 clinical practice guideline for optimal hemodialysis treatment.

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists' support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient's condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There are also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

Circulating miRNAs in extracellular vesicles related to treatment response in patients with idiopathic membranous nephropathy.

BACKGROUND: Extracellular vesicle (EV)-microRNAs (miRNAs) are potential biomarkers for various renal diseases. This study attempted to identify the circulating EV-miRNA signature not only for discriminating idiopathic membranous nephropathy (IMN) from idiopathic nephrotic syndrome (INS), but also to predict the treatment response of patients with IMN. METHODS: We prospectively enrolled 60 participants, including those with IMN (n = 19) and INS (n = 21) and healthy volunteers (HVs; n = 20) in this study. Using RNA sequencing, we assessed the serum EV-miRNA profiles of all participants. To identify the EV-miRNAs predictive of treatment response in IMN, we also analyzed EV-miRNAs among patients with IMN with and without clinical remission. RESULTS: The expression levels of 3 miRNAs differed between IMN patients, INS patients and HVs. In addition, compared to HVs, RNA sequencing revealed differential expression of 77 and 44 EV-miRNAs in patients with IMN without and with remission, respectively. We also identified statistically significant (|fold change ≥ 2, p < 0.05) differences in the expression levels of 23 miRNAs in IMN without remission. Biological pathway analysis of miRNAs in IMN without remission indicated that they are likely involved in various pathways, including renal fibrosis. CONCLUSION: Our study identified EV-miRNAs associated with IMN as well as those associations with therapeutic response. Therefore, these circulating EV-miRNAs may be used as potential markers for the diagnosis and prediction of treatment response in patients with IMN.

Weight Change Alters the Small RNA Profile of Urinary Extracellular Vesicles in Obesity.

INTRODUCTION: Various kidney diseases reportedly show different urinary extracellular vesicle (EV) RNA profiles. Although obesity is one of the main causes of chronic kidney disease, the expression pattern of urinary EV RNA in obesity is uncertain. Our aim was to sequence the small RNA profiles of urinary EVs in obese patients before and after weight reduction and compare them to those of healthy volunteers (HVs). METHODS: We recruited age-sex-matched obese patients and HVs. The small RNA profiles of urinary EVs were analyzed using RNA sequencing. To evaluate the effect of weight reduction, small RNA profiles of urinary EVs 6 months after bariatric surgery were also analyzed. RESULTS: The proportion of urinary EVs transfer RNA and microRNA of obese patients differed from that of HVs. Obese patients showed differential expression of 1,343 small RNAs in urinary EVs compared to HVs (fold change ≥2 and p value <0.05). Among those, 61 small RNAs were upregulated in obese patients and downregulated after weight reduction, whereas 167 small RNAs were downregulated in obese patients and upregulated after weight reduction. RNA sequencing revealed the correlation between the specific urinary EV small RNAs and clinical parameters including body weight, low-density lipoprotein cholesterol, triglyceride, high-density lipoprotein cholesterol, serum glucose, estimated glomerular filtration rate, and albuminuria. CONCLUSION: Obese patients showed distinct urinary EV small RNA profiles compared to HVs. Weight reduction altered urinary EV small-RNA profiles in obese patients.

Association between blood pressure and the risk of chronic kidney disease in treatment-naïve hypertensive patients.

BACKGROUND: Although hypertension is a well-known risk factor for chronic kidney disease (CKD), the blood pressure (BP) at which antihypertensive interventions should be initiated remains to be determined. Therefore, we investigated the association between BP and CKD in treatment-naïve individuals. METHODS: This prospective cohort study considered 7,343 individuals in the Korean Genome and Epidemiology Study who were not taking antihypertensive medications. Subjects were categorized into six groups according to their systolic BP (SBP) and five groups according to their diastolic BP (DBP). The primary outcome was incident CKD, which was defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m2 or the development of proteinuria. The secondary outcome was incident cardiovascular disease (CVD). RESULTS: In the time-varying Cox models, the hazard ratios (95% confidence interval [CI]) for CKD were 1.39 (1.10-1.77) with SBP 130-139 mmHg, 1.79 (1.40-2.28) with SBP 140-159 mmHg, and 3.22 (2.35-4.40) with SBP ≥ 160 mmHg, compared with SBP 100-119 mmHg. In addition, the hazard ratios (95% CI) for CKD were 1.88 (1.48-2.37) with DBP 90-99 mmHg and 4.30 (3.20-5.76) with DBP ≥ 100 mmHg, compared with DBP 70-79 mmHg. A significantly increased CVD risk was also observed in subjects with SBP ≥ 130 mmHg or DBP ≥ 90 mmHg. CONCLUSION: Our findings indicate that SBP ≥ 130 mmHg and DBP ≥ 90 mmHg are associated with an increased risk of CKD. Therefore, BP-lowering strategies should be considered starting at those thresholds to prevent CKD development.

Low bone mineral density is associated with coronary arterial calcification progression and incident cardiovascular events in patients with chronic kidney disease.

BACKGROUND: Although it is well known that low bone mineral density (BMD) is associated with an increased risk of cardiovascular disease (CVD) and mortality in the general population, the prognostic role of bone mineral density (BMD) has not been established in the chronic kidney disease (CKD) population. Therefore we aimed to evaluate the association between BMD and the risk of CVD and cardiovascular mortality in patients with predialysis CKD. METHODS: This prospective cohort study was conducted with 1957 patients with predialysis CKD Stages 1-5. BMD was measured using dual-energy X-ray absorptiometry and coronary arterial calcification (CAC) scores were evaluated using coronary computed tomography. The primary outcome was a major adverse cardiovascular event (MACE). RESULTS: When patients were classified based on total hip BMD T-score tertiles stratified by sex, the lowest BMD tertile was significantly associated with an increased risk of MACE {hazard ratio 2.16 [95% confidence interval (CI) 1.25-3.74]; P = 0.006}. This association was also shown with BMD at the femur neck but not with BMD at lumbar spine. In the subgroup of 977 patients with follow-up CACs at their fourth year, 97 (9.9%) showed accelerated CAC progression (>50/year), and BMD was inversely associated with accelerated CAC progression even after adjusting for the baseline CAC score [odds ratio 0.75 (95% CI 0.58-0.99); P = 0.039]. In addition, baseline CAC was associated with an increased risk of MACEs after adjusting for total hip T-score. CONCLUSIONS: Low BMD was significantly associated with CAC progression and MACEs in patients with predialysis CKD.

Abdominal periaortic and renal sinus fat attenuation indices measured on computed tomography are associated with metabolic syndrome.

OBJECTIVES: To investigate the association between abdominal periaortic (APA) and renal sinus (RS) fat attenuation index (FAI) measured on MDCT and metabolic syndrome in non-obese and obese individuals. METHODS: Visceral, subcutaneous, RS, and APA adipose tissue were measured in preoperative abdominal CT scans of individuals who underwent donor nephrectomy (n = 84) or bariatric surgery (n = 155). FAI was defined as the mean attenuation of measured fat volume. Participants were categorized into four groups: non-obese without metabolic syndrome (n = 64), non-obese with metabolic syndrome (n = 25), obese without metabolic syndrome (n = 21), and obese with metabolic syndrome (n = 129). The volume and FAI of each fat segment were compared among the groups. Receiver operator characteristics curve analysis was used to assess the association between the FAIs and metabolic syndrome. RESULTS: FAIs of all abdominal fat segments were significantly lower in the obese group than in the non-obese group (p < 0.001). RS, APA, and the visceral adipose tissue FAIs were significantly lower in participants with metabolic syndrome than in those without metabolic syndrome in the non-obese group (p < 0.001, p = 0.006, and p < 0.001, respectively). The area under the curve for predicting metabolic syndrome was significantly higher for APA FAI (0.790) than subcutaneous, visceral, and RS FAI in all groups (0.649, 0.647, and 0.655, respectively). CONCLUSION: Both metabolic syndrome and obesity were associated with lower RS and APA adipose tissue FAI, and APA FAI performed best for predicting metabolic syndrome. KEY POINTS: • The volume and FAI of RS, APA, and visceral adipose tissue showed opposite trends with regard to metabolic syndrome or obesity. • Both metabolic syndrome and obesity were associated with lower RS FAI and APA FAI. • APA FAI performed best for predicting metabolic syndrome among FAIs of abdominal fat segments.

Pericoronary fat attenuation index in computed tomography angiography is associated with mortality in end-stage renal disease.

BACKGROUND: An increased pericoronary fat attenuation index (FAI) on computed tomography angiography (CTA) is associated with increased all-cause and cardiac mortality in the general population. However, the ability of pericoronary FAI to predict long-term outcomes in chronic kidney disease (CKD) patients is unknown. METHODS: In this single-center retrospective longitudinal cohort study, we assessed the utility of CTA-based pericoronary FAI measurement to predict mortality of CKD patients, including those with end-stage renal disease (ESRD). Mapping and analysis of pericoronary FAI involved three major proximal coronary arteries. The prognostic value of pericoronary FAI for long-term mortality was assessed with multivariable Cox regression models. RESULTS: Among 268 CKD participants who underwent coronary CTA, 209 participants with left anterior descending artery (LAD) FAI measurements were included. The pericoronary FAI measured at the LAD was not significantly associated with adjusted risk of allcause mortality (hazard ratio [HR], 2.08; 95% confidence interval [CI], 0.94-3.51) in any CKD group. However, ESRD patients with elevated pericoronary FAI values had a greater adjusted risk of all-cause mortality compared with the low-FAI group (HR, 2.26; 95% CI, 1.11-4.61). CONCLUSION: The pericoronary FAI measured at the LAD predicted long-term mortality in patients with ESRD, which could provide an opportunity for early primary intervention in ESRD patients.

Executive Summary of the Korean Society of Nephrology 2021 Clinical Practice Guideline for Optimal Hemodialysis Treatment.

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists' support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient's condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There is also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).