Unveiling the enigma of acute kidney disease: predicting prognosis, exploring interventions, and embracing a multidisciplinary approach.

Acute kidney disease (AKD) is a critical transitional period between acute kidney injury and chronic kidney disease. The incidence of AKD following acute kidney injury is approximately 33.6%, and it can occur without identifiable preceding acute kidney injury. The development of AKD is associated with increased risks of chronic kidney disease, dialysis, and mortality. Biomarkers and subphenotypes are promising tools to predict prognosis in AKD. The complex clinical situations in patients with AKD necessitate a comprehensive and structured approach, termed "KAMPS" (kidney function check, advocacy, medications, pressure, sick day protocols). We introduce "MAND-MASS," an acronym devised to summarize the reconciliation of medications during episodes of acute illness, as a critical component of the sick day protocols at AKD. A multidisciplinary team care, consisting of nephrologists, pharmacists, dietitians, health educators, and nurses, is an optimal model to achieve the care bundle in KAMPS. Although the evidence for patients with AKD is still lacking, several potential pharmacological agents may improve outcomes, including but not limited to angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide 1 receptor agonists. In conclusion, accurate prognosis prediction and effective treatment for AKD are critical yet unmet clinical needs. Future studies are urgently needed to improve patient care in this complex and rapidly evolving field.

Biomarkers in pursuit of precision medicine for acute kidney injury: hard to get rid of customs.

Traditional acute kidney injury (AKI) classifications, which are centered around semi-anatomical lines, can no longer capture the complexity of AKI. By employing strategies to identify predictive and prognostic enrichment targets, experts could gain a deeper comprehension of AKI's pathophysiology, allowing for the development of treatment-specific targets and enhancing individualized care. Subphenotyping, which is enriched with AKI biomarkers, holds insights into distinct risk profiles and tailored treatment strategies that redefine AKI and contribute to improved clinical management. The utilization of biomarkers such as N-acetyl-ß-D-glucosaminidase, tissue inhibitor of metalloprotease-2·insulin-like growth factor-binding protein 7, kidney injury molecule-1, and liver fatty acid-binding protein garnered significant attention as a means to predict subclinical AKI. Novel biomarkers offer promise in predicting persistent AKI, with urinary motif chemokine ligand 14 displaying significant sensitivity and specificity. Furthermore, they serve as predictive markers for weaning patients from acute dialysis and offer valuable insights into distinct AKI subgroups. The proposed management of AKI, which is encapsulated in a structured flowchart, bridges the gap between research and clinical practice. It streamlines the utilization of biomarkers and subphenotyping, promising a future in which AKI is swiftly identified and managed with unprecedented precision. Incorporating kidney biomarkers into strategies for early AKI detection and the initiation of AKI care bundles has proven to be more effective than using care bundles without these novel biomarkers. This comprehensive approach represents a significant stride toward precision medicine, enabling the identification of high-risk subphenotypes in patients with AKI.

Percutaneous Coronary Intervention With a Drug-Eluting Stent Versus Coronary Artery Bypass Grafting in Patients Receiving Dialysis: A National Study From Taiwan.

Rationale & Objective: We aimed to study the comparative effectiveness of percutaneous coronary intervention with drug-eluting stent and coronary artery bypass grafting in patients receiving dialysis. Study Design: This was a retrospective observational cohort study. Setting & Participants: This population-based study identified patients receiving dialysis hospitalized for coronary revascularization between January 1, 2009 and December 31, 2015, in the Taiwan National Health Insurance Research Database. Exposures: Patients received percutaneous coronary intervention with drug-eluting stent versus coronary artery bypass grafting. Outcomes: The study outcomes were all-cause mortality, in-hospital mortality, and repeat revascularization. Analytical Approach: Propensity scores were used to match patients. Cox proportional hazards models and logistic regression models were constructed to examine associations between revascularization strategies and mortality. Interval Cox models were fitted to estimate time-varying hazards during different periods. Results: A total of 1,840 propensity score-matched patients receiving dialysis were analyzed. Coronary artery bypass grafting was associated with higher in-hospital mortality (coronary artery bypass grafting vs percutaneous coronary intervention with drug-eluting stent; crude mortality rate 12.5% vs 3.3%; adjusted OR, 5.22; 95% CI, 3.42-7.97; P < 0.001) and longer hospitalization duration (median [IQR], 20 [14-30] days vs 3 [2-8] days; P < 0.001). After discharge, repeat revascularization, acute coronary syndrome, and repeat hospitalization all occurred more frequently in the percutaneous coronary intervention with drug-eluting stent group. Importantly, with a median follow-up of 2.8 years, coronary artery bypass grafting was significantly associated with a higher risk of all-cause overall mortality (adjusted HR, 1.19; 95% CI, 1.05-1.35; P = 0.006) in the multivariable Cox proportional hazard model. Sensitivity and subgroup analyses yielded consistent results. Limitations: This was an observational study with mainly Asian ethnicity. Conclusions: Percutaneous coronary intervention with drug-eluting stent may be associated with better survival than coronary artery bypass grafting in patients receiving dialysis. Future studies are warranted to confirm this finding.

Although coronary artery bypass grafting offers better long-term survival in the general population than percutaneous coronary intervention with drug-eluting stent, patients receiving dialysis may be too frail to tolerate the increased perioperative mortality risk of coronary artery bypass grafting. In this retrospective study in a national cohort of patients receiving dialysis from Taiwan, percutaneous coronary intervention with drug-eluting stent is associated with lower in-hospital mortality and better long-term survival when compared with coronary artery bypass grafting. Subsequent acute coronary syndrome, repeat revascularization, and rehospitalization were noted more frequently in the percutaneous coronary intervention with drug-eluting stent group. These findings may suggest percutaneous coronary intervention with drug-eluting stent as a safe revascularization strategy for patients receiving dialysis.

The effects of double-filtration plasmapheresis on coagulation profiles and the risk of bleeding.

BACKGROUND/PURPOSE: Double-filtration plasmapheresis (DFPP) can be used to remove circulating pathogenic molecules. By reclaiming filtered albumin, DFPP reduces the need for albumin and plasma replacement. Large proteins, such as fibrinogen, are removed. Our institution adopts a DFPP treatment protocol consisting of active surveillance of coagulation profiles and prophylactic supplementation of blood products containing fibrinogen. This study aims to investigate the effects of consecutive DFPP treatments on serial coagulation profiles and the risk of bleeding under this protocol. METHODS: Serial laboratory data and bleeding events at a single tertiary medical center were prospectively collected. Prophylactic transfusion of cryoprecipitate or fresh frozen plasma (FFP) was instituted if significant coagulopathy or a clinically evident bleeding event was observed. RESULTS: After the first treatment session, plasma fibrinogen levels decreased from 332 ± 106 mg/dL to 96 ± 44 mg/dL in the 37 study patients. In the following sessions, plasma fibrinogen levels were maintained at around 100 mg/dL under prophylactic transfusion. No major bleeding events were recorded, but five (14%) patients experienced minor bleeding. CONCLUSION: DFPP treatment might be performed safely along with active monitoring of coagulation profiles and prophylactic transfusion of cryoprecipitate or FFP.

Update of pericytes function and their roles in kidney diseases.

Studies have highlighted the significant involvement of kidney pericytes in renal fibrosis. Kidney pericytes, classified as interstitial mesenchymal cells, are extensively branched, collagen-producing cells that closely interact with endothelial cells. This article aims to provide an overview of the recent advancements in understanding the physiological functions of pericytes and their roles in kidney diseases. In a healthy kidney, pericytes have essential physiological function in angiogenesis, erythropoietin (EPO) production, and the regulation of renal blood flow. Nevertheless, pericyte-myofibroblast transition has been identified as the primary cause of disease progression in acute kidney injury (AKI)-to-chronic kidney disease (CKD) continuum. Our recent research has demonstrated that hypoxia-inducible factor-2α (HIF-2α) regulates erythropoietin production in pericytes. However, this production is repressed by EPO gene hypermethylation and HIF-2α downregulation which were induced by transforming growth factor-ß1-activated DNA methyltransferase and activin receptor-like kinase-5 signaling pathway during renal fibrosis, respectively. Additionally, AKI induces epigenetic modifications in pericytes, rendering them more prone to extracellular matrix production, cell migration and proliferation, thereby contributing to subsequent capillary rarefaction and renal fibrosis. Further investigation into the specific functions and roles of different subpopulations of pericytes may contribute for the development of targeted therapies aimed at attenuating kidney disease and mitigating their adverse effects.

Extremely Low Dose of Erythropoiesis-Stimulating Agent May Be Associated with Increased Mortality in Hemodialysis Patients.

INTRODUCTION: Although high-dose erythropoiesis-stimulating agent (ESA) has been shown to increase mortality risk and adverse cardiovascular events in hemodialysis patients, the safety of extremely low-dose ESA is unclear. METHODS: We retrospectively analyzed the association between ESA dose and mortality in the monthly dosing range of 0-43,000 U of equivalent epoetin alfa in 304 Taiwan hemodialysis patients by using Cox proportional hazard model and cubic spline model. RESULTS: Compared with mean monthly ESA dose of 15,000-25,000 U (mean ± standard deviation 20,609 ± 2,662 U), monthly ESA dose of less than 15,000 U (mean ± standard deviation 7,413 ± 4,510 U) is associated with increased mortality. Monthly ESA dose of 25,001-43,000 U (mean ± standard deviation 31,160 ± 4,304 U) is not associated with higher mortality risk than monthly ESA dose of 15,000-25,000 U. The results were consistent in Cox proportional hazard models and cubic spline models. Subgroup analyses showed no significant heterogeneities among prespecified subgroups. CONCLUSIONS: Extremely low dose of ESA in hemodialysis patients may be associated with increased mortality risk. Future studies are warranted to prove this association.

Pleotropic effects of hypoxia-inducible factor-prolyl hydroxylase domain inhibitors: are they clinically relevant?

Anemia is common in patients with chronic kidney disease (CKD) and is mainly caused by insufficient production of erythropoietin from fibrotic kidney. Because anemia impairs quality of life and overall prognosis, recombinant human erythropoietin-related products (erythropoiesis-stimulating agents, ESAs) have been developed to increase hemoglobin level for decades. However, many safety concerns have been announced regarding the use of ESAs, including an increased occurrence of cardiovascular events, vascular access thrombosis, cancer progression, and recurrence. Hypoxia-inducible factor (HIF) is crucial to erythropoietin production, as a result, prolyl hydroxylase domain (PHD) enzyme inhibitors have been new therapeutic agents for the treatment of anemia in CKD. They can be administered orally, which is a preferred route for patients not undergoing hemodialysis. In clinical trials, PHD inhibitor could induce noninferior effect on erythropoiesis and improve functional iron deficiency compared with ESAs. Although no serious adverse events were reported, safety is still a concern because HIF stabilization induced by PHD inhibitor has pleotropic effects, such as angiogenesis, metabolic change, and cell survival, which might lead to unwanted deleterious effects, including fibrosis, inflammation, cardiovascular risk, and tumor growth. More molecular mechanisms of PHD inhibition and long-term clinical trials are needed to observe these pleotropic effects for the confirmation of safety and efficacy of PHD inhibitors.

Humoral antibody response to the first dose of the ChAdOx1 nCoV-19 vaccine in Asian patients undergoing hemodialysis.

BACKGROUND AND OBJECTIVES: The immunogenicity of vaccines is known to be attenuated in patients with end-stage kidney disease due to uremia. Patients on dialysis were excluded from coronavirus disease 2019 (COVID-19) vaccine trials; thus, the effectiveness of vaccines for this population is unclear. The aim of this study was to explore whether Asian dialysis patients can effectively produce an immune response after being vaccinated with the first dose of the ChAdOx1 nCoV-19 vaccine. DESIGN SETTING, PARTICIPANTS, AND MEASUREMENTS: In this prospective cohort study, we included Asian hemodialysis patients who received the ChAdOx1 nCoV-19 vaccine. At 3 weeks after the first dose of vaccination, we assessed the humoral immune response by measuring anti-SARS-CoV-2 S antibody titers. The primary outcome was the seropositive rate following vaccination, defined as an antibody titer greater than or equal to 0.8 U/ml. Factors associated with seropositivity were explored in multivariate logistic regression analyses. RESULTS: In total, 434 participants were included. The mean age was 64 years, the mean dialysis vintage was 6 years, and 61% of the participants were men. At a mean time of 22 days from vaccination, 56% of the participants were seropositive. The vast majority (88%) had low antibody titers (< 15 U/ml). The multivariate logistic regression analyses showed that older age (every increase of 10 years, odds ratio [OR] 0.80, 95% CI 0.65-0.98, p = 0.03) was negatively associated with seropositivity and that higher Kt/V (every increase of 0.1, OR 1.14, 95% CI 1.01-1.28, p = 0.03) and higher serum albumin level (every increase of 0.1 g/dl, OR 1.09, 95% CI 1.02-1.18, p = 0.02) were positively associated with seropositivity. CONCLUSIONS: In Asian hemodialysis patients, the seropositive rate was low, and most had low antibody titers after the first dose of the ChAdOx1 nCoV-19 vaccine. Younger age, better dialysis adequacy, and higher albumin levels were associated with seropositivity.

Transforming growth factor-ß1 decreases erythropoietin production through repressing hypoxia-inducible factor 2α in erythropoietin-producing cells.

BACKGROUND: Renal erythropoietin (EPO)-producing (REP) cells produce EPO through hypoxia-inducible factor (HIF) 2α-activated gene transcription. Insufficient EPO production leads to anemia in patients with chronic kidney disease. Although recombinant EPO is effective to improve anemia, no reliable REP cell lines limit further progress of research and development of novel treatment. METHODS: We screened Epo mRNA expression in mouse fibroblast cell lines. Small interfering RNA specific for HIF1α or HIF2α was transfected to study Epo expression in C3H10T1/2 cells. The effect of transforming growth factor-ß1 (TGF-ß1) on HIF-EPO axis was studied in C3H10T1/2 cells and mice. RESULTS: Similar to mouse REP pericytes, C3H10T1/2 cells differentiated to α-smooth muscle actin+ myofibroblasts after exposure to TGF-ß1. Specific HIF knockdown demonstrated the role of HIF2α in hypoxia-induced Epo expression. Sustained TGF-ß1 exposure increased neither DNA methyltransferase nor methylation of Epas1 and Epo genes. However, TGF-ß1 repressed HIF2α-encoding Epas1 promptly through activating activin receptor-like kinase-5 (ALK5), thereby decreasing Epo induction by hypoxia and prolyl hydroxylase domain inhibitor roxadustat. In mice with pro-fibrotic injury induced by ureteral obstruction, upregulation of Tgfb1 was accompanied with downregulation of Epas1 and Epo in injured kidneys and myofibroblasts, which were reversed by ALK5 inhibitor SB431542. CONCLUSION: C3H10T1/2 cells possessed the property of HIF2α-dependent Epo expression in REP pericytes. TGF-ß1 induced not only the transition to myofibroblasts but also a repressive effect on Epas1-Epo axis in C3H10T1/2 cells. The repressive effect of TGF-ß1 on Epas1-Epo axis was confirmed in REP pericytes in vivo. Inhibition of TGF-ß1-ALK5 signaling might provide a novel treatment to rescue EPO expression in REP pericytes of injured kidney.

Kidney pericyte hypoxia-inducible factor regulates erythropoiesis but not kidney fibrosis.

Prolyl hydroxylase domain enzyme (PHD) inhibitors are effective in the treatment of chronic kidney disease (CKD)-associated anemia by stabilizing hypoxia inducible factor (HIF), thereby increasing erythropoietin and consequently erythropoiesis. However, concern for CKD progression needs to be addressed in clinical trials. Although pre-clinical studies showed an anti-inflammatory effect in kidney disease models, the effect of PHD inhibitors on kidney fibrosis was inconsistent probably because the effects of HIF are cell type and context dependent. The major kidney erythropoietin-producing cells are pericytes that produce erythropoietin through HIF-2α-dependent gene transcription. The concern for the impact of HIF in pericytes on kidney fibrosis arises from the fact that pericytes are the major precursor cells of myofibroblasts in CKD. Since cells expressing Gli1 fulfill the morphologic and anatomic criteria for pericytes, we induced Gli1+ cell-specific HIF stabilization or knockout to study the impact of HIF in pericytes on kidney pathology of mice with or without fibrotic injury induced by unilateral ureteral obstruction. Compared with the littermate controls, mice with pericyte-specific HIF stabilization due to von Hippel-Lindau protein or PHD2 knockout showed increased serum erythropoietin and polycythemia rather than a discernible difference in kidney fibrosis. Compared with Gli1+ pericytes sorted from littermate controls, Gli1+ pericytes sorted from PHD2 knockout mice showed increased erythropoietin gene expression rather than discernible changes in Col1a1 or Acta2 expression. Furthermore, pericyte-specific knockout of HIF-1α or HIF-2α did not affect kidney fibrosis. Thus, our study supports the absence of negative effects of PHD inhibitors on kidney fibrosis of mice despite HIF stabilization in pericytes.

Observation of 990-MHz Optical Oscillation From Light Emitters Excited by High-Order Harmonics of Surface Acoustic Waves.

Optomechanical properties have been widely explored on the interactions between phonon, photon, and electrons. The applications range from acoustic filters for mobile handsets to quantum information science./However, up to date, the interaction between harmonic modes of surface acoustic waves (SAWs) and photons has not been studied in detail. Here, we develop radio frequency (RF) - modulated light emitters driven by the coupling between electrical and acoustic signals at room temperature. The light emitter demonstrates a 990-MHz oscillation behavior which cannot be solely achieved by electrical driving due to resistance-capacitance (RC) limit. Instead, the result is attributed to the excitation by the harmonics of SAWs in the light emitter. The ~gigahertz light oscillation enables a new architecture for information processing. In this work, we also demonstrate the coupling between acoustooptical and electrooptical interactions by simultaneously applying 990-MHz acoustic signals and 20-MHz modulated electrical inputs.

The journey from erythropoietin to 2019 Nobel Prize: Focus on hypoxia-inducible factors in the kidney.

The 2019 Nobel Prize in Physiology or Medicine was awarded to William G. Kaelin Jr, Sir Peter J. Ratcliffe, and Gregg L. Semenza "for their discoveries of how cells sense and adapt to oxygen availability." The three pioneers discovered the hypoxia-inducible factor (HIF), elucidated the oxygen sensing mechanism of cells, and confirmed the critical role of HIF in hypoxic cellular responses. The broad and profound biological effects of HIF open up the possibilities for clinical translation. HIF stabilizers have been proven effective on anemia of chronic kidney disease in phase III clinical trials. HIF antagonists for cancer treatment are under phase II clinical trials. It is imperative to gain insight into the biology of HIF. In this article, the discovery of HIF and its oxygen-dependent enzymatic regulation will be introduced, based largely on the groundbreaking work of the three Nobel laureates. Next, the biology of HIF in the kidney will be reviewed. Studies on the HIF stabilizers in the context of kidney disease, as well as the manipulation of HIF in different renal cell types will be covered. Lastly, the clinical application of HIF stabilizers and HIF antagonists for the treatment of anemia and cancer, respectively, will be discussed.

Emergence of T cell immunosenescence in diabetic chronic kidney disease.

BACKGROUND: Type 2 diabetes is an important challenge given the worldwide epidemic and is the most important cause of end-stage renal disease (ESRD) in developed countries. It is known that patients with ESRD and advanced renal failure suffer from immunosenescence and premature T cell aging, but whether such changes develop in patients with less severe chronic kidney disease (CKD) is unclear. METHOD: 523 adult patients with type 2 diabetes were recruited for this study. Demographic data and clinical information were obtained from medical chart review. Immunosenescence, or aging of the immune system was assessed by staining freshly-obtained peripheral blood with immunophenotyping panels and analyzing cells using multicolor flow cytometry. RESULT: Consistent with previously observed in the general population, both T and monocyte immunosenescence in diabetic patients positively correlate with age. When compared to diabetic patients with preserved renal function (estimated glomerular filtration rate > 60 ml/min), patients with impaired renal function exhibit a significant decrease of total CD3+ and CD4+ T cells, but not CD8+ T cell and monocyte numbers. Immunosenescence was observed in patients with CKD stage 3 and in patients with more severe renal failure, especially of CD8+ T cells. However, immunosenescence was not associated with level of proteinuria level or glucose control. In age, sex and glucose level-adjusted regression models, stage 3 CKD patients exhibited significantly elevated percentages of CD28-, CD127-, and CD57+ cells among CD8+ T cells when compared to patients with preserved renal function. In contrast, no change was detected in monocyte subpopulations as renal function declined. In addition, higher body mass index (BMI) is associated with enhanced immunosenescence irrespective of CKD status. CONCLUSION: The extent of immunosenescence is not significantly associated with proteinuria or glucose control in type 2 diabetic patients. T cells, especially the CD8+ subsets, exhibit aggravated characteristics of immunosenescence during renal function decline as early as stage 3 CKD. In addition, inflammation increases since stage 3 CKD and higher BMI drives the accumulation of CD8+CD57+ T cells. Our study indicates that therapeutic approaches such as weight loss may be used to prevent the emergence of immunosenescence in diabetes before stage 3 CKD.

Targeting fibroblast CD248 attenuates CCL17-expressing macrophages and tissue fibrosis.

The role of fibroblasts in tissue fibrosis has been extensively studied. Activated fibroblasts, namely myofibroblasts, produce pathological extracellular matrix. CD248, a type I transmembrane glycoprotein, is expressed in fibroblasts after birth. In human chronic kidney disease, upregulated CD248 in myofibroblasts is linked to poor renal survival. In this study, we demonstrated a novel interaction between CD248 and macrophages to be a key step in mediating tissue fibrosis. CD248 was upregulated in myofibroblasts in murine models of renal and peritoneal fibrosis. Cd248 knockout (Cd248-/-) could attenuate both renal and peritoneal fibrosis. By parabiosis of GFP reporter mice and Cd248-/- mice, we showed that attenuation of renal fibrosis was associated with a decrease of macrophage infiltration in Cd248-/- mice. Moreover, decrease of chemokine (C-C motif) ligand 17 and Ccl22 was found in macrophages isolated from the fibrotic kidneys of Cd248-/- mice. Because galectin-3-deficient macrophages showed decreased Ccl17 and Ccl22 in fibrotic kidneys, we further demonstrated that CD248 interacted specifically with galectin-3 of macrophages who then expressed CCL17 to activate collagen production in myofibroblasts. Mice with DNA vaccination targeting CD248 showed decreased fibrosis. We thus propose that CD248 targeting should be studied in the clinical tissue fibrosis setting.

Methylation in pericytes after acute injury promotes chronic kidney disease.

The origin and fate of renal myofibroblasts is not clear after acute kidney injury (AKI). Here, we demonstrate that myofibroblasts were activated from quiescent pericytes (qPericytes) and the cell numbers increased after ischemia/reperfusion injury-induced AKI (IRI-AKI). Myofibroblasts underwent apoptosis during renal recovery but one-fifth of them survived in the recovered kidneys on day 28 after IRI-AKI and their cell numbers increased again after day 56. Microarray data showed the distinctive gene expression patterns of qPericytes, activated pericytes (aPericytes, myofibroblasts), and inactivated pericytes (iPericytes) isolated from kidneys before, on day 7, and on day 28 after IRI-AKI. Hypermethylation of the Acta2 repressor Ybx2 during IRI-AKI resulted in epigenetic modification of iPericytes to promote the transition to chronic kidney disease (CKD) and aggravated fibrogenesis induced by a second AKI induced by adenine. Mechanistically, transforming growth factor-ß1 decreased the binding of YBX2 to the promoter of Acta2 and induced Ybx2 hypermethylation, thereby increasing α-smooth muscle actin expression in aPericytes. Demethylation by 5-azacytidine recovered the microvascular stabilizing function of aPericytes, reversed the profibrotic property of iPericytes, prevented AKI-CKD transition, and attenuated fibrogenesis induced by a second adenine-AKI. In conclusion, intervention to erase hypermethylation of pericytes after AKI provides a strategy to stop the transition to CKD.

Plasma Leucine-Rich α-2-Glycoprotein 1 Predicts Cardiovascular Disease Risk in End-Stage Renal Disease.

Plasma leucine-Rich α-2-glycoprotein 1 (LRG1) is an innovative biomarker for inflammation and angiogenesis. Many adverse pathophysiological changes including inflammation, atherosclerosis, and premature mortality is associated with End-stage renal disease (ESRD). However, whether levels of plasma LRG1 correlate with the co-morbidities of ESRD patients is unknown. Plasma LRG1 and high-sensitivity C-reactive protein (hsCRP) were analyzed by ELISA in 169 hemodialysis patients from the Immunity in ESRD (iESRD) study. Patient demographics and comorbidities at the time of enrollment were recorded. Peripheral blood monocyte and T cell subsets were assessed by multicolor flow cytometry. In the univariate analysis, a higher level of LRG1 was associated with the presence of cardiovascular disease (CVD) and peripheral arterial occlusive disease (PAOD). In multivariate logistic regression models, higher LRG1 tertile was significantly associated with PAOD (odds ratio = 3.49) and CVD (odds ratio = 1.65), but not with coronary artery disease, history of myocardial infarction, or stroke after adjusting for gender, diabetes, hemoglobin, albumin, calcium-phosphate product, and level of hsCRP. In addition, the level of LRG1 had a positive correlation with IL-6, hsCRP, and also more advanced T cell differentiation. The association suggests that LRG1 participates in the progression of atherosclerosis by inducing inflammation. Therefore, the role of LRG1 in coexisting inflammatory response should be further investigated in the pathogenesis of cardiovascular morbidity and mortality in patients with ESRD.

Rejuvenation: Turning back the clock of aging kidney.

Aging is inevitable in life. It is defined as impaired adaptive capacity to environmental or internal stresses with growing rates of disease and death. Aging is also an important risk factor for various kidney diseases such as acute kidney injury and chronic kidney disease. Patients older than 65 years have nearly 28% risk of failing recovery of kidney function when suffering from acute kidney injury. It is reported that more than a third of population aged 65 years and older have chronic kidney disease in Taiwan, and the occurrence of multiple age-related disorders is predicted to increase in parallel. Renal aging is a complex, multifactorial process characterized by many anatomical and functional changes. Several factors are involved in renal aging, such as loss of telomeres, cell cycle arrest, chronic inflammation, activation of renin-angiotensin system, decreased klotho expression, and development of tertiary lymphoid tissues. These changes can also be observed in many other different types of renal injury. Recent studies suggested that young blood may rejuvenate aged organs, including the kidneys. In order to develop new therapeutic strategies for renal aging, the mechanisms underlying renal aging and by which young blood can halt or reverse aging process warrants further study.

Inflammatory macrophages switch to CCL17-expressing phenotype and promote peritoneal fibrosis.

Peritoneal fibrosis remains a problem in kidney failure patients treated with peritoneal dialysis. Severe peritoneal fibrosis with encapsulation or encapsulating peritoneal sclerosis is devastating and life-threatening. Although submesothelial fibroblasts as the major precursor of scar-producing myofibroblasts in animal models and M2 macrophage (Mϕ)-derived chemokines in peritoneal effluents of patients before diagnosis of encapsulating peritoneal sclerosis have been identified, attenuation of peritoneal fibrosis is an unmet medical need partly because the mechanism for cross talk between Mϕs and fibroblasts remains unclear. We use a sodium hypochlorite-induced mouse model akin to clinical encapsulated peritoneal sclerosis to study how the peritoneal Mϕs activate fibroblasts and fibrosis. Sodium hypochlorite induces the disappearance of CD11bhigh F4/80high resident Mϕs but accumulation of CD11bint F4/80int inflammatory Mϕs (InfMϕs) through recruiting blood monocytes and activating local cell proliferation. InfMϕs switch to express chemokine (C-C motif) ligand 17 (CCL17), CCL22, and arginase-1 from day 2 after hypochlorite injury. More than 75% of InfMϕs undergo genetic recombination by Csf1r-driven Cre recombinase, providing the possibility to reduce myofibroblasts and fibrosis by diphtheria toxin-induced Mϕ ablation from day 2 after injury. Furthermore, administration of antibody against CCL17 can reduce Mϕs, myofibroblasts, fibrosis, and improve peritoneal function after injury. Mechanistically, CCL17 stimulates migration and collagen production of submesothelial fibroblasts in culture. By breeding mice that are induced to express red fluorescent protein in Mϕs and green fluorescence protein (GFP) in Col1a1-expressing cells, we confirmed that Mϕs do not produce collagen in peritoneum before and after injury. However, small numbers of fibrocytes are found in fibrotic peritoneum of chimeric mice with bone marrow from Col1a1-GFP reporter mice, but they do not contribute to myofibroblasts. These data demonstrate that InfMϕs switch to pro-fibrotic phenotype and activate peritoneal fibroblasts through CCL17 after injury. CCL17 blockade in patients with peritoneal fibrosis may provide a novel therapy. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

A comprehensive characterization of aggravated aging-related changes in T lymphocytes and monocytes in end-stage renal disease: the iESRD study.

BACKGROUND: Patients with end-stage renal disease (ESRD) exhibit a premature aging phenotype of the immune system. Nevertheless, the etiology and impact of these changes in ESRD patients remain unknown. RESULTS: Compared to healthy individuals, ESRD patients exhibit accelerated immunosenescence in both T cell and monocyte compartments, characterized by a dramatic reduction in naïve CD4+ and CD8+ T cell numbers but increase in CD8+ TEMRA cell and proinflammatory monocyte numbers. Notably, within ESRD patients, aging-related immune changes positively correlated not only with increasing age but also with longer dialysis vintage. In multivariable-adjusted logistic regression models, the combination of high terminally differentiated CD8+ T cell level and high intermediate monocyte level, as a composite predictive immunophenotype, was independently associated with prevalent coronary artery disease as well as cardiovascular disease, after adjustment for age, sex, systemic inflammation and presence of diabetes. Levels of terminally differentiated CD8+ T cells also positively correlated with the level of uremic toxin p-cresyl sulfate. CONCLUSIONS: Aging-associated adaptive and innate immune changes are aggravated in ESRD and are associated with cardiovascular diseases. For the first time, our study demonstrates the potential link between immunosenescence in ESRD and duration of exposure to the uremic milieu.