Predicting CKD progression using time-series clustering and light gradient boosting machines.

Predicting the transition of kidney function in chronic kidney disease is difficult as specific symptoms are lacking and often overlooked, and progress occurs due to complicating factors. In this study, we applied time-series cluster analysis and a light gradient boosting machine to predict the trajectories of kidney function in non-dialysis dependent chronic kidney disease patients with baseline estimated glomerular filtration rate (GFR) ≥ 45 mL/min/1.73 m2. Based on 5-year changes in estimated GFR, participants were stratified into groups with similar trajectories by cluster analysis. Next, we applied the light gradient boosting machine algorithm and Shapley addictive explanation to develop a prediction model for clusters and identify important parameters for prediction. Data from 780 participants were available for analysis. Participants were classified into five classes (Class 1: n = 78, mean [± standard deviation] estimated GFR 100 ± 19.3 mL/min/1.73 m2; Class 2: n = 176, 76.0 ± 9.3 mL/min/1.73 m2; Class 3: n = 191, 59.8 ± 5.9 mL/min/1.73 m2; Class 4: n = 261, 52.7 ± 4.6 mL/min/1.73 m2; and Class 5: n = 74, 53.5 ± 12.0 mL/min/1.73 m2). Declines in estimated GFR were 8.9% in Class 1, 12.2% in Class 2, 4.9% in Class 3, 12.0% in Class 4, and 45.1% in Class 5 during the 5-year period. The accuracy of prediction was 0.675, and the top three most important Shapley addictive explanation values were 1.61 for baseline estimated GFR, 0.12 for hemoglobin, and 0.11 for body mass index. The estimated GFR transition of patients with preserved chronic kidney disease mostly depended on baseline estimated GFR, and the borderline for estimated GFR trajectory was nearly 50 mL/min/1.73 m2.

Changes in Metabolomic Profiles Induced by Switching from an Erythropoiesis-Stimulating Agent to a Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor in Hemodialysis Patients: A Pilot Study.

Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) are a new class of medications for managing renal anemia in patients with chronic kidney disease (CKD). In addition to their erythropoietic activity, HIF-PHIs exhibit multifaceted effects on iron and glucose metabolism, mitochondrial metabolism, and angiogenesis through the regulation of a wide range of HIF-responsive gene expressions. However, the systemic biological effects of HIF-PHIs in CKD patients have not been fully explored. In this prospective, single-center study, we comprehensively investigated changes in plasma metabolomic profiles following the switch from an erythropoiesis-stimulating agent (ESA) to an HIF-PHI, daprodustat, in 10 maintenance hemodialysis patients. Plasma metabolites were measured before and three months after the switch from an ESA to an HIF-PHI. Among 106 individual markers detected in plasma, significant changes were found in four compounds (erythrulose, n-butyrylglycine, threonine, and leucine), and notable but non-significant changes were found in another five compounds (inositol, phosphoric acid, lyxose, arabinose, and hydroxylamine). Pathway analysis indicated decreased levels of plasma metabolites, particularly those involved in phosphatidylinositol signaling, ascorbate and aldarate metabolism, and inositol phosphate metabolism. Our results provide detailed insights into the systemic biological effects of HIF-PHIs in hemodialysis patients and are expected to contribute to an evaluation of the potential side effects that may result from long-term use of this class of drugs.

A case of systemic sarcoidosis with mesangial proliferative glomerulonephritis showing predominant deposition of IgG in the mesangial region.

A 37-year-old African-British man was referred to our hospital for detailed examination because of persistent fever, swelling and pain in both ankle joints, and blurred vision for two months. Inguinal lymph node biopsy showed a large number of epithelioid granulomas without necrosis. Granulomatous anterior uveitis, nephropathy, high serum angiotensin-converting enzyme activity, and high serum-soluble interleukin-2 receptor were observed, and the diagnosis of systemic sarcoidosis was made. His serum creatinine was 1.4 mg/dL and hematuria, leukocyturia, and urine protein were also seen. The renal biopsy finding was mesangial proliferative glomerulonephritis, with no findings of granuloma formation or tubular interstitial nephritis. Immunofluorescence staining showed deposition of IgG, C3, and C1q in the mesangial region. IgG3 was dominant in subclass staining. There was no monoclonality on kappa and lambda staining. Electron microscopy showed predominant deposition in the mesangial region with some subepithelial and endothelial deposition. His hematuria and leukocyturia disappeared with steroid therapy, suggesting sarcoidosis-related nephropathy. A case of systemic sarcoidosis with mesangial proliferative glomerulonephritis showing predominant deposition of IgG in the mesangial region is presented. No cases of such histological findings have been reported so far, and it is necessary to analyze further cases to clarify the pathogenic significance of the renal biopsy findings observed in this case.

Different clinical impact of hyperuricemia according to etiologies of chronic kidney disease: Gonryo Study.

BACKGROUND: Hyperuricemia is highly prevalent in chronic kidney disease (CKD) patients, but the evidence for a relationship between uric acid (UA) and clinical outcomes in CKD patients is limited and inconsistent. We hypothesized that UA has a different impact on clinical outcomes according to the underlying disease causing CKD. METHODS: This study prospectively investigated the associations between UA and renal and non-renal outcomes according to the underlying disease causing CKD in 2,797 Japanese patients under the care of nephrologists. The patients were categorized into four groups: primary renal disease (n = 1306), hypertensive nephropathy (n = 467), diabetic nephropathy (n = 275), and other nephropathy (n = 749). The renal outcome was defined as end-stage renal disease (ESRD), and the non-renal outcome was defined as a composite endpoint of cardiovascular events (CVEs) and all-cause mortality. RESULTS: During a median 4.8-year follow-up, 359 (12.8%) patients reached the renal outcome, and 260 (9.3%) reached the non-renal outcome. In the all-patient analysis, hyperuricemia was not associated with the risks for renal and non-renal outcomes, but in primary renal disease (PRD) and hypertensive renal disease (HTN) patients, hyperuricemia was significantly associated with non-renal outcomes. Per 1 mg/dl higher UA level, multivariable adjusted hazard ratio was 1.248 (95% CI: 1.003 to 1.553) for PRD, and 1.250 (1.035 to 1.510) for HTN. Allopurinol did not reduce the risks for renal and non-renal outcomes, both in all patients and in the subgroup analysis. CONCLUSIONS: The effect of hyperuricemia on clinical outcomes in CKD patients varies according to the underlying disease causing CKD. Hyperuricemia is an independent risk factor for non-renal outcomes in primary renal disease and hypertensive renal disease patients. Allopurinol did not decrease the risks for renal and non-renal outcomes.

Translational Research of Peritoneal Dialysis Solution with Dissolved Molecular Hydrogen.

BACKGROUND: Improved biocompatibility of peritoneal dialysis solution (PDS) is crucial for peritoneal membrane preservation, thereby ensuring long-term peritoneal dialysis (PD) and preventing encapsulating peritoneal sclerosis. We previously reported the protective effect of molecular hydrogen (H2) on mesothelial cells from PDS in nonuremic rats. SUMMARY: In the present study, we examined the effect of H2-containing PDS (commercially available neutral pH type) regarding the protection of peritoneal tissue in experimental chronic kidney disease rats. Furthermore, we conducted a 2-week clinical trial in which H2-containing PDS was used in place of standard PDS and its feasibility was examined. In the experimental study, test solutions were injected through the subcutaneous port into the abdomen for 3 weeks. Histological study revealed a significant increase in the number of mesothelial cells and a significant decrease in peritoneal thickness in the H2-PD group as compared to the control and PD groups. Also, results of immunostaining analysis revealed increased vimentin and apoptotic cells in the membrane of the PD group, indicating that H2 may play a role in ameliorating PDS-induced peritoneal injury and preserving peritoneal integrity. In the clinical trial with 6 prevalent PD patients, all subjects completed the study with no adverse effects. Moreover, there were substantial changes in surrogate markers, such as increased CA125 and mesothelin, in the effluent in selected cases, suggesting enhanced mesothelial regeneration by H2. Key Message: H2-enriched PDS is a candidate novel PDS with improved biocompatibility. Further, our results support the significance of H2-PD clinical trials in the future.

Skin autofluorescence is associated with the progression of chronic kidney disease: a prospective observational study.

BACKGROUND: Advanced glycation end product (AGE) accumulation is thought to be a measure of cumulative metabolic stress that has been reported to independently predict cardiovascular disease in diabetes and renal failure. The aim of this study was to evaluate the association between AGE accumulation, measured as skin autofluorescence, and the progression of renal disease in pre-dialysis patients with chronic kidney disease (CKD). METHODS: Skin autofluorescence was measured noninvasively with an autofluorescence reader at baseline in 449 pre-dialysis patients with CKD. The primary end point was defined as a doubling of serum creatinine and/or need for dialysis. RESULTS: Thirty-three patients were lost to follow-up. Forty six patients reached the primary end point during the follow-up period (Median 39 months). Kaplan-Meier analysis showed a significantly higher risk of development of the primary end points in patients with skin autofluorescence levels above the optimal cut-off level of 2.31 arbitrary units, derived by receiver operator curve analysis. Cox regression analysis revealed that skin autofluorescence was an independent predictor of the primary end point, even after adjustment for age, gender, smoking history, diabetes, estimated glomerular filtration rate and proteinuria (adjusted hazard ratio 2.58, P = 0.004). CONCLUSIONS: Tissue accumulation of AGEs, measured as skin autofluorescence, is a strong and independent predictor of progression of CKD. Skin autofluorescence may be useful for risk stratification in this group of patients; further studies should clarify whether AGE accumulation could be one of the therapeutic targets to improve the prognosis of CKD.

Hypertrophic cranial pachymeningitis in MPO-ANCA-related vasculitis: a case report and literature review.

A 75-year-old woman presented with rapidly progressive glomerulonephritis with positive results for anti-myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA). Corticosteroid therapy was successfully introduced. However, 7 months later, magnetic resonance imaging revealed marked swelling in the falx cerebri and high density regions were apparent on gallium scintigraphy, leading to diagnosis of hypertrophic cranial pachymeningitis (HCP). Symptoms improved with intensified corticosteroid therapy, but radiological examination 9 months later revealed right nasal sinus inflammation accompanied by osteolytic change. Granulomatosis with polyangiitis (Wegener's) was finally diagnosed. HCP is an important complication in MPO-ANCA-related vasculitis, and needs to be considered during the clinical course.

Dietary Perilla seed oil supplement increases plasma omega-3 polyunsaturated fatty acids and ameliorates immunoglobulin A nephropathy in high immunoglobulin A strain of ddY mice.

BACKGROUND/AIMS: The beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFA) in the treatment of immunoglobulin A nephropathy (IgAN) have been reported. Perilla frutescens (Linn.) Britton var. frutescens is grown in Eastern Asia and its seed (perilla seed) is rich in α-linolenic acid, an n-3 PUFA. We investigated the antinephritic effects of perilla seed oil in a mouse model of IgAN. METHODS: Ten-week-old high IgA ddY mice were fed diets containing either perilla seed oil (PS group) or corn oil (C group, control). After 20 weeks, we compared body weight, blood pressure, serum creatinine levels, IgA levels, fatty acid composition, urinary protein excretion, mesangial matrix expansion, and glomerular transforming growth factor-ß1 mRNA expression between groups. RESULTS: Serum n-3 PUFA levels were higher in the PS group than the C group (p<0.001). Blood urea nitrogen levels were lower (p=0.0246) and urinary protein excretion was reduced (p=0.0198) in the PS group. Mesangial matrix expansion (p=0.0063) and glomerular transforming growth factor-ß1 mRNA expression (p=0.0291) were suppressed in the PS group. No significant differences between groups were found in body weight, blood pressure, serum IgA, and creatinine levels. CONCLUSIONS: Dietary perilla seed oil supplement could suppress the progression of IgAN.