Protective effect of Cyclo(His-Pro) on peritoneal fibrosis through regulation of HDAC3 expression.

Peritoneal dialysis is a common treatment for end-stage renal disease, but complications often force its discontinuation. Preventive treatments for peritoneal inflammation and fibrosis are currently lacking. Cyclo(His-Pro) (CHP), a naturally occurring cyclic dipeptide, has demonstrated protective effects in various fibrotic diseases, yet its potential role in peritoneal fibrosis (PF) remains uncertain. In a mouse model of induced PF, CHP was administered, and quantitative proteomic analysis using liquid chromatography-tandem mass spectrometry was employed to identify PF-related protein signaling pathways. The results were further validated using human primary cultured mesothelial cells. This analysis revealed the involvement of histone deacetylase 3 (HDAC3) in the PF signaling pathway. CHP administration effectively mitigated PF in both peritoneal tissue and human primary cultured mesothelial cells, concurrently regulating fibrosis-related markers and HDAC3 expression. Moreover, CHP enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) while suppressing forkhead box protein M1 (FOXM1), known to inhibit Nrf2 transcription through its interaction with HDAC3. CHP also displayed an impact on spleen myeloid-derived suppressor cells, suggesting an immunomodulatory effect. Notably, CHP improved mitochondrial function in peritoneal tissue, resulting in increased mitochondrial membrane potential and adenosine triphosphate production. This study suggests that CHP can significantly prevent PF in peritoneal dialysis patients by modulating HDAC3 expression and associated signaling pathways, reducing fibrosis and inflammation markers, and improving mitochondrial function.

Soluble suppression of tumorigenicity 2 is a potential predictor of post-liver transplant renal outcomes.

Acute kidney injury is considered an independent prognostic factor for mortality in patients with liver cirrhosis. Non-treated acute kidney injury can progress to hepatorenal syndrome with a poor prognosis. As suppression of tumorigenicity 2 (ST2) is a member of the interleukin-1 receptor family that aggravates inflammation and fibrotic changes in multiple organs, we measured soluble ST2 (sST2) level in the serum and urine of liver-transplant recipients at the time of transplantation. The serum sST2 level significantly increased in liver-transplant recipients with suppressed kidney function compared with that in recipients with normal function. In recipients with severely decreased liver function (model for end-stage liver disease score ≥ 30), the serum sST2 level was higher than that in recipients with preserved liver function (model for end-stage liver disease score ≤ 20, P = 0.028). The serum sST2 level in recipients with hepatorenal syndrome was higher than that in liver-transplant recipients without hepatorenal syndrome (P = 0.003). The serum sST2 level in patients with hepatorenal syndrome was higher than that in recipients without a history of acute kidney injury (P = 0.004). Recipients with hepatorenal syndrome and recovered kidney function showed higher sST2 levels than those who did not recover (P = 0.034). Collectively, an increase in the serum sST2 level reflects a decrease in both kidney and liver functions. Thus, measuring sST2 level at the time of liver transplantation can help predict renal outcomes.

Inhibiting Transglutaminase 2 Mediates Kidney Fibrosis via Anti-Apoptosis.

Transglutaminase 2 (TG2) is a calcium-dependent transamidating acyltransferase enzyme of the protein-glutamine γ-glutamyltransferase family implicated in kidney injury. In this study, we identified associations between TG2 and chronic kidney disease (CKD) identified by visualizing TG2 in kidney biopsy samples derived from CKD patients using immunohistochemistry and measuring the plasma TG2 concentrations. Our study revealed a connection between TG2 and the pathological markers of kidney disease. We showed high plasma TG2 levels in samples from patients with advanced CKD. In addition, we observed an increase in TG2 expression in tissues concomitant with advanced CKD in human samples. Moreover, we investigated the effect of TG2 inhibition on kidney injury using cystamine, a well-known competitive inhibitor of TG2. TG2 inhibition reduced apoptosis and accumulation of extracellular molecules (ECM) such as fibronectin and pro-inflammatory cytokine IL-8. Collectively, the increased expression of TG2 that was observed in advanced CKD, hence inhibiting TG2 activity, could protect kidney cells from ECM molecule accumulation, apoptosis, and inflammatory responses, thereby preventing kidney fibrosis.

Renoprotective Effect of KLF2 on Glomerular Endothelial Dysfunction in Hypertensive Nephropathy.

Kruppel-like factor 2 (KLF2) regulates endothelial cell metabolism; endothelial dysfunction is associated with hypertension and is a predictor of atherosclerosis development and cardiovascular events. Here, we investigated the role of KLF2 in hypertensive nephropathy by regulating KLF2 expression in human primary glomerular endothelial cells (hPGECs) and evaluating this expression in the kidney tissues of a 5/6 nephrectomy mouse model as well as patients with hypertension. Hypertension-mimicking devices and KLF2 siRNA were used to downregulate KLF2 expression, while the expression of KLF2 was upregulated by administering simvastatin. After 4 mmHg of pressure was applied on hPGECs for 48 h, KLF2 mRNA expression decreased, while alpha-smooth muscle actin (αSMA) mRNA expression increased. Apoptosis and fibrosis rates were increased under pressure, and these phenomena were aggravated following KLF2 knockdown, but were alleviated after simvastatin treatment; additionally, these changes were observed in angiotensin II, angiotensin type-1 receptor (AT1R) mRNA, and interleukin-18 (IL-18), but not in angiotensin type-2 receptor mRNA. Reduced expression of KLF2 in glomerular endothelial cells due to hypertension was found in both 5/6 nephrectomy mice and patients with hypertensive nephropathy. Thus, our study demonstrates that the pressure-induced apoptosis and fibrosis of glomerular endothelial cells result from angiotensin II, AT1R activation, and KLF2 inhibition, and are associated with IL-18.

Additive harmful effects of acute kidney injury and acute heart failure on mortality in hospitalized patients.

BACKGROUND: Organ crosstalk between the kidney and the heart has been suggested. Acute kidney injury (AKI) and acute heart failure (AHF) are well-known independent risk factors for mortality in hospitalized patients. This study aimed to investigate if these conditions have an additive effect on mortality in hospitalized patients, as this has not been explored in previous studies. METHODS: We retrospectively reviewed the records of 101,804 hospitalized patients who visited two tertiary hospitals in the Republic of Korea over a period of 5 years. AKI was diagnosed using serum creatinine-based criteria, and AHF was classified using International Classification of Diseases codes within 2 weeks after admission. Patients were divided into four groups according to the two conditions. The primary outcome was all-cause mortality. RESULTS: AKI occurred in 6.8% of all patients (n = 6,920) and AHF in 1.2% (n = 1,244). Three hundred thirty-one patients (0.3%) developed both conditions while AKI alone was present in 6,589 patients (6.5%) and AHF alone in 913 patients (0.9%). Among the 5,181 patients (5.1%) who died, 20.8% died within 1 month. The hazard ratio for 1-month mortality was 29.23 in patients with both conditions, 15.00 for AKI only, and 3.39 for AHF only. The relative excess risk of interaction was 11.85 (95% confidence interval, 2.43-21.27), and was more prominent in patients aged <75 years and those without chronic heart failure. CONCLUSION: AKI and AHF have a detrimental additive effect on short-term mortality in hospitalized patients.

Role of the IL-33/ST2 pathway in renal allograft rejection.

The interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) pathway modulates immune response and inflammation, associated with allograft dysfunction and rejection. We hypothesized that IL-33/ST2 is a marker of renal allograft rejection and IL-33/ST2 expression may differ according to rejection type. IL-33/ST2 expression was measured in sera and kidney tissues from recipients with acute antibody-mediated rejection (AAMR), acute cell-mediated rejection (ACMR), chronic antibody-mediated rejection (CAMR), and healthy controls. The soluble ST2 and IL-33/ST2 expression levels were higher in participants with all three rejection types than in controls. Although the expression levels in recipients with AAMR and ACMR were significantly higher than those with CAMR, there was no significant difference between the expression levels in AAMR and ACMR. Although IL-33, IL-8, and fibronectin expression were significantly increased after the addition of the recipients' serum in primary cultured human renal proximal tubular epithelial cells, the levels decreased after treatment with an anti-ST2 antibody. Furthermore, the anti-ST2 antibody specifically suppressed the upregulation of the mixed lymphocyte reaction. Boyden chamber assays demonstrated that anti-ST2 antibody abrogated chemotaxis induced by recombinant IL-33. Thus, IL-33 and ST2 are potent mediators of rejection. Treatment with an anti-ST2 antibody ameliorates rejection and could be a potential therapeutic strategy for renal allograft rejection.

Comprehensive metabolomic profiling in early IgA nephropathy patients reveals urine glycine as a prognostic biomarker.

Identification of a urinary metabolite biomarker with diagnostic or prognostic significance for early immunoglobulin A nephropathy (IgAN) is needed. We performed nuclear magnetic resonance-based metabolomic profiling and identified 26 metabolites in urine samples. We collected urine samples from 201, 77, 47, 36 and 136 patients with IgAN, patients with membranous nephropathy, patients with minimal change disease, patients with lupus nephritis and healthy controls, respectively. We determined whether a metabolite level is associated with the prognosis of IgAN through Cox regression and continuous net reclassification improvement (cNRI). Finally, in vitro experiments with human kidney tubular epithelial cells (hTECs) were performed for experimental validation. As the results, the urinary glycine level was higher in the IgAN group than the control groups. A higher urinary glycine level was associated with lower risk of eGFR 30% decline in IgAN patients. The addition of glycine to a predictive model including clinicopathologic information significantly improved the predictive power for the prognosis of IgAN [cNRI 0.72 (0.28-0.82)]. In hTECs, the addition of glycine ameliorated inflammatory signals induced by tumour necrosis factor-α. Our study demonstrates that urinary glycine may have diagnostic and prognostic value for IgAN and indicates that urinary glycine is a protective biomarker for IgAN.

Nationwide Glaucoma incidence in end stage renal disease patients and kidney transplant recipients.

Glaucoma shares common risk factors with chronic kidney disease (CKD) but previous cross-sectional studies have demonstrated discrepancies in the risk of glaucoma in CKD patients. This study enrolled kidney transplantation recipients (KTRs) (n = 10,955), end stage renal disease (ESRD) patients (n = 10,955) and healthy controls (n = 10,955) from National Health Insurance Service database of the Republic of Korea. A Cox proportional hazard regression model was used to calculate the hazard ratios (HR) for primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) incidences. The incidence of POAG was higher in ESRD patients (3.36/1,000 person-years, P < 0.0001) and KTRs (3.22 /1,000 person-years, P < 0.0001), than in healthy controls (1.20/1,000 person-years). However, POAG risk showed no significant increase in either ESRD patients (P = 0.07) or KTRs (P = 0.08) when adjusted for the confounding factors. The incidence of PACG was significantly higher in ESRD patients (0.41/1,000 person-years) than in healthy controls (0.14/1,000 person-years, P = 0.008). The PACG incidence was significantly lower in KTRs than in ESRD patients (HR = 0.35, P = 0.015). In conclusion, this nationwide cohort study demonstrated that kidney transplantation can reduce the risk of PACG but not POAG in ESRD patients.

Multisample Mass Spectrometry-Based Approach for Discovering Injury Markers in Chronic Kidney Disease.

Urinary proteomics studies have primarily focused on identifying markers of chronic kidney disease (CKD) progression. Here, we aimed to determine urinary markers of CKD renal parenchymal injury through proteomics analysis in animal kidney tissues and cells and in the urine of patients with CKD. Label-free quantitative proteomics analysis based on liquid chromatography-tandem mass spectrometry was performed on urine samples obtained from 6 normal controls and 9, 11, and 10 patients with CKD stages 1, 3, and 5, respectively, and on kidney tissue samples from a rat CKD model by 5/6 nephrectomy. Tandem mass tag-based quantitative proteomics analysis was performed for glomerular endothelial cells (GECs) and proximal tubular epithelial cells (PTECs) before and after inducing 24-h hypoxia injury. Upon hierarchical clustering, out of 858 differentially expressed proteins (DEPs) in the urine of CKD patients, the levels of 416 decreased and 403 increased sequentially according to the disease stage, respectively. Among 2965 DEPs across 5/6 nephrectomized and sham-operated rat kidney tissues, 86 DEPs showed same expression patterns in the urine and kidney tissue. After cross-validation with two external animal proteome data sets, 38 DEPs were organized; only ten DEPs, including serotransferrin, gelsolin, poly ADP-ribose polymerase 1, neuroblast differentiation-associated protein AHNAK, microtubule-associated protein 4, galectin-1, protein S, thymosin beta-4, myristoylated alanine-rich C-kinase substrate, and vimentin, were finalized by screening human GECs and PTECs data. Among these ten potential candidates for universal CKD marker, validation analyses for protein S and galectin-1 were conducted. Galectin-1 was observed to have a significant inverse correlation with renal function as well as higher expression in glomerulus with chronic injury than protein S. This constitutes the first multisample proteomics study for identifying key renal-expressed proteins associated with CKD progression. The discovered proteins represent potential markers of chronic renal cell and tissue damage and candidate contributors to CKD pathophysiology.

Weaning Immunosuppressant in Patients with Failing Kidney Grafts and The Outcomes: A Single-Center Retrospective Cohort Study.

An immunosuppressant weaning protocol in failing allografts has not yet been established. Maintaining immunosuppressants would preserve residual renal function (RRF) and prevent graft intolerance syndrome and sensitization but would increase the risks of infection and malignancy. In this study, graft failure cases after kidney transplantation in a single center were reviewed retrospectively. The outcome differences in all-cause mortality, infection-related hospitalization, cancer, graft intolerance syndrome, re-transplantation, and RRF duration between the immunosuppressant maintaining and weaning groups 6 months after graft failure were compared. Among the weaning group, the outcome differences according to low-dose steroid use were also compared at 6 and 12 months. In a total of 131 graft failure cases, 18 mortalities, 42 infection-related hospitalizations, 22 cancer cases, 11 graft intolerance syndrome cases, and 28 re-transplantations occurred during the 94-month follow-up. Immunosuppressant maintenance significantly decreased the patient survival rate 6 months after graft failure compared with weaning (log-rank P = 0.008) and was an independent risk factor for mortality, even after adjustments (hazard ratio, 3.01; P = 0.025). Infection-related hospitalization, graft intolerance syndrome development, and re-transplantation were not affected by the immunosuppressant weaning protocol. Among the immunosuppressant weaning group, low-dose steroid maintenance at 6 and 12 months helped preserved RRF (P = 0.008 and P = 0.003, respectively).

Association of hypoalbuminemia with short-term and long-term mortality in patients undergoing continuous renal replacement therapy.

BACKGROUND: Hypoalbuminemia reflects several pathological conditions, including nutritional deficiencies and chronic inflammation. However, its relationship with short-term and long-term mortality in patients undergoing continuous renal replacement therapy (CRRT) remains unclear. The present study aimed to assess the effect of hypoalbuminemia on mortality in a large cohort of patients undergoing CRRT. METHODS: The study retrospectively reviewed 1,581 patients who underwent CRRT for the treatment of acute kidney injury from 2010 to 2016. The patients were categorized by tertiles of serum albumin levels at CRRT initiation. The odds ratios and hazard ratios for the risk of all-cause mortality were calculated before and after adjustment for multiple covariates. RESULTS: The mean albumin level was 2.7 ± 0.6 g/dL at CRRT initiation. During a median follow-up period of 14 days (maximum, 4 years), 1,040 patients (65.8%) died. The risk of overall mortality was higher in the first tertile group than in the third tertile group (hazard ratio, 1.9 [1.63-2.21]). When the mortality rate was stratified by timeframe, the risk was steadily higher in the first tertile group than in the third tertile group (odds ratios: 3.0 [2.34-3.87] for 2-week mortality, 2.7 [2.12-3.52] for 1-month mortality, 2.7 [2.08-3.53] for 6-month mortality, and 2.8 [2.11-3.62] for 1-year mortality). Additionally, the rates of intensive care unit mortality and in-hospital mortality were higher in the first tertile group than in the third tertile group. CONCLUSION: The initial hypoalbuminemia was independently associated with short-term and long-term mortality in patients undergoing CRRT. Thus, the serum albumin level should be monitored during CRRT.

The Effect of Health-Related Behaviors on Disease Progression and Mortality in Early Stages of Chronic Kidney Disease: A Korean Nationwide Population-Based Study.

A healthy life style is associated with decreased risk of chronic kidney disease (CKD) and mortality in the general population. However, there is no definitive evidence of the benefits of physical activity and other health-related behaviors in the early-stage of CKD. This study aimed to explore the association between health-related behaviors and end-stage renal disease (ESRD) and mortality in the early stages of CKD. The National Health Insurance Service (NHIS) database from 1 January 2009 to 31 December 2016 was used to screen 83,470 subjects with early stage CKD. Cox proportional hazard regression analysis was used to evaluate the association between health-related behaviors and ESRD and death. Kaplan-Meier curves for mortality and ESRD were plotted according to the physical activity, smoking status, and alcohol consumption pattern. Risk of death decreased significantly in subjects who engaged in sufficient physical activity (adjusted Hazard Ratio (HR) 0.73; 95% CI: 0.64-0.83; p < 0.001). Risk of ESRD and death increased significantly in the current smoker with adjusted HR of 1.44 (95% CI: 1.06-1.95; p < 0.02) and 1.61 (95% CI: 1.44-1.80; p < 0.001) respectively. Therefore, systematic interventions to encourage physical activity and smoking cessation need to be actively considered in the early stages of CKD.

Efficacy of low-dose spironolactone on top of angiotensin receptor blockade in patients with glomerulonephritis.

BACKGROUND: Previous studies have shown that aldosterone antagonists have a proteinuria-lowering effect in patients with proteinuria and progressive proteinuric disease not adequately controlled by the use of angiotensin receptor blockers (ARBs). Aldosterone antagonists, in combination with ARBs, might improve proteinuria in patients with glomerulonephritis (GN). METHODS: In the present retrospective study, we evaluated the proteinuria-lowering effect and drug safety of low-dose spironolactone (12.5 mg/day) in 42 patients with GN being treated with an ARB. RESULTS: Proteinuria decreased from a mean total-protein-to-creatinine (TP/Cr) ratio of 592.3 ± 42.0 mg/g at baseline to 335.6 ± 43.3 mg/g after three months of treatment with spironolactone (P < 0.001). After the initial three months, the mean TP/Cr ratio increased progressively at six, nine, and 12 months; however, it was still less than the baseline value (P = 0.001, < 0.001, and < 0.001, respectively). Although serum Cr levels increased significantly at three and nine months compared with baseline (P = 0.036 and 0.026, respectively), there was no time effect of treatment (P = 0.071). Serum potassium levels tended to increase with time (P = 0.118), whereas systolic and diastolic blood pressures decreased with time (P = 0.122 and 0.044, respectively). CONCLUSION: Low-dose spironolactone in combination with an ARB reduced proteinuria in patients with GN, which could represent a novel treatment option in individuals whose proteinuria is not optimally controlled by the use of ARBs alone.

Successful synchronous chemotherapy and radiotherapy followed by consecutive chemotherapy without surgery for primary intracranial choriocarcinoma: A case report.

We experienced a rare case of primary intracranial choriocarcinoma treated successfully with synchronous chemotherapy and radiotherapy followed by three consecutive courses of chemotherapy without surgery. A 19-year-old male patient presented with a two-week history of diplopia, headache, nausea and vomiting. Neurological examination revealed visual disturbance, bilateral hearing loss, bilateral sixth nerve palsy, left skew deviation, downgaze limitation and clockwise torsional nystagmus on the left upgaze. During image evaluation, the patient suddenly presented with a confused mental status, bradycardia and decreased respiration. An emergency third ventriculostomy was conducted, followed by synchronous ifosfamide, cisplatin and etoposide chemotherapy (ICE; I, 900 mg/m(2); C, 20 mg/m(2); and E, 60 mg/m(2)) on days 1-5, and external radiotherapy (whole brain, 30 Gy/15 Fxs; local boost, 30 Gy/15 Fxs) followed again by three consecutive courses of chemotherapy. This therapy resulted in tumor regression by 63% and full improvement in the patient's neurological condition. However, it was difficult to remove the remaining tumor using a surgical approach due to the risk of postoperative hemorrhage and limited access. We planned to observe the remaining mass without surgery. This patient is now alive and the mass size has not changed for 18 months since treatment. This is the first report of the effectiveness of synchronous chemotherapy and radiotherapy followed by consecutive chemotherapy without surgery in a patient with primary intracranial choriocarcinoma.