Glomerular function in relation to circulating adhesion molecules and inflammation markers in a general population

Plasma soluble tumor necrosis factor receptor I as a biomarker of lupus nephritis and disease activity in systemic lupus erythematosus patients

OBJECTIVES

The goal of our study was to evaluate the potential role of sTNF-RI as a biomarker of renal involvement in SLE patients and active SLE.

METHODS

The study sample consisted of two cohorts. The discovery cohort included 16 SLE patients without renal involvement (non-LN), 60 lupus nephritis (LN) patients and 21 healthy controls (HCs) and the replication cohort included 18 SLE non-LN patients, 116 LN patients and 36 HCs.

RESULTS

The sTNF-RI levels differed significantly in the discovery cohort. The plasma sTNF-RI levels were higher in LN patients than in non-LN patients (p = .009) and HCs (p = 4 × 10^-6). Plasma sTNF-RI levels were significantly higher in non-LN patients than in HCs (p = .03). The finding was confirmed in independent replication cohort (LNs vs. non-LN, p = 4.053 × 10^-7; LNs vs. HCs, p = 2.395 × 10^-18; non-LN vs. HCs, p = 2.51 × 10^-4). The plasma sTNF-RI levels were associated with disease activity, renal function in SLE patients and urine protein in LN patients. The multivariate analysis revealed that high sTNF-RI was an independent risk factor for renal involvement. The multivariate logistic regression results suggested that high TNF-RI, high systolic blood pressure, high serum creatinine, low C4 and positive anti-dsDNA were independent risks of active SLE patients. A nomogram was constructed based on the results of multivariate logistic regression analysis and it was practical in predicting the risk of the active SLE patients. Immunohistochemistry suggested that the expression of TNF-RI in the kidney was increased.

CONCLUSIONS

Plasma sTNF-RI might be a good biomarker of renal involvement and disease activity in SLE patients.

Leukocyte-endothelial interaction in CKD

Chronic kidney disease (CKD) represents an independent risk factor for cardiovascular diseases (CVD). Accordingly, CKD patients show a substantial increased risk of cardiovascular mortality. Inflammation represents an important link between CKD and CVD. The interaction between endothelial cells and effector cells of the innate immune system plays a central role in the development and progression of inflammation. Vascular injury causes endothelial dysfunction, leading to augmented oxidative stress, increased expression of leukocyte adhesion molecules and chronic inflammation. CKD induces numerous metabolic changes, creating a uremic milieu resulting in the accumulation of various uremic toxins. These toxins lead to vascular injury, endothelial dysfunction and activation of the innate immune system. Recent studies describe CKD-dependent changes in monocytes that promote endothelial dysfunction and thus CKD progression and CKD-associated CVD. The NLR family pyrin domain containing 3-interleukin-1β-interleukin-6 (NLRP3-IL-1β-IL-6) signaling pathway plays a pivotal role in the development and progression of CVD and CKD alike. Several clinical trials are investigating targeted inhibition of this pathway indicating that anti-inflammatory therapeutic strategies may emerge as novel approaches in patients at high cardiovascular risk and nonresolving inflammation. CKD patients in particular would benefit from targeted anti-inflammatory therapy, since conventional therapeutic regimens have limited efficacy in this population.

Biomarkers of the End-Stage Renal Disease Progression: Beyond the GFR

Chronic kidney disease can progress to the end-stage renal disease (ESRD) characterized by a high risk of morbidity and mortality. ESRD requires immediate therapy or even dialysis or kidney transplantation, therefore, its timely diagnostics is critical for many patients. ESRD is associated with pathological changes, such as inflammation, fibrosis, endocrine disorders, and epigenetic changes in various cells, which could serve as ESRD markers. The review summarizes information on conventional and new ESRD biomarkers that can be assessed in kidney tissue, blood, and urine. Some biomarkers are specific to a particular pathology, while others are more universal. Here, we suggest several universal inflammatory, fibrotic, hormonal, and epigenetic markers indicative of severe deterioration of renal function and ESRD progression for improvement of ESRD diagnostics.

Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.

Chronic Kidney Disease and Periodontitis Interplay-A Narrative Review

Periodontitis (PO), a chronic microbially-induced inflammation of the supporting tissues of the tooth, is linked to various systemic diseases. We analyze its bidirectional relationship to chronic kidney disease (CKD), a major health-care problem with impressive excess mortality. Overwhelming associative relationship between CKD and PO are analyzed. Major pathophysiologic mechanisms that link CKD to PO are then presented: systemic inflammation, endothelial dysfunction, and imbalance of oxidative stress characteristic of CKD have a role in PO development and might influence escape mechanisms of oral microbiota. Subclinical local and systemic inflammation induced by PO might influence in turn CKD outcomes. Homeostatic changes induced by CKD such as mineral bone disorders, acidosis, uremic milieu, or poor salivary flow are also relevant for the occurrence of PO. There is insufficient evidence to recommend a standardized diagnostic and therapeutic approach regarding association of PO to CKD.

The role of VCAM-1 in diabetic retinopathy: A systematic review and meta-analysis

OBJECTIVE

Vascular cell adhesion molecule-1 (VCAM-1) plays a regulatory role in inflammatory diseases. However, the exact role of VCAM-1 in diabetic retinopathy (DR) remains unclear, and there is a lack of meta-analyses.

METHODS

The role of VCAM-1 in DR was screened by database searching. A random effects model was used, and the estimated mean difference was evaluated.

RESULTS

Twenty articles were included. The level of VCAM-1 increased significantly in the DR group compared with the control group (SMD: 0.67, 95 % CI: 0.34-1.01, P < 0.0001). VCAM-1 levels correlated with sample size and DR type, method and severity based on subgroup analysis.

CONCLUSION

A high level of VCAM-1 is present in DR patients and is related to the severity of DR. Therefore, VCAM-1 is a potential detection biomarker for DR.

Targeted biomarkers of progression in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is an increasingly significant health issue worldwide. Early stages of CKD can be asymptomatic and disease trajectory difficult to predict. Not everyone with CKD progresses to kidney failure, where kidney replacement therapy is the only life-sustaining therapy. Predicting which patients will progress to kidney failure would allow better use of targeted treatments and more effective allocation of health resources. Current diagnostic tests to identify patients with progressive disease perform poorly but there is a suite of new and emerging predictive biomarkers with great clinical promise.

METHODS

This narrative review describes new and emerging biomarkers of pathophysiologic processes of CKD development and progression, accessible in blood or urine liquid biopsies. Biomarkers were selected based on their reported pathobiological functions in kidney injury, inflammation, oxidative stress, repair and fibrosis. Biomarker function and evidence of involvement in CKD development and progression are reported.

CONCLUSION

Many biomarkers reviewed here have received little attention to date, perhaps because of conflicting conclusions of their utility in CKD. The functional roles of the selected biomarkers in the underlying pathobiology of progression of CKD are a powerful rationale for advancing and validating these molecules as prognosticators and predictors of CKD trajectory.

Εndothelial and microvascular function in CKD: Evaluation methods and associations with outcomes

BACKGROUND

Cardiovascular disease is the major cause of morbidity and mortality in patients with chronic kidney disease (CKD). Endothelial dysfunction, the hallmark of atherosclerosis, is suggested to be involved pathogenetically in cardiovascular and renal disease progression in these patients.

METHODS

This is a narrative review presenting the techniques and markers used for assessment of microvascular and endothelial function in patients with CKD and discussing findings of the relevant studies on the associations of endothelial dysfunction with co-morbid conditions and outcomes in this population.

RESULTS

Venous Occlusion Plethysmography was the first method to evaluate microvascular function; subsequently, several relevant techniques have been developed and used in patients with CKD, including brachial Flow-Mediated Dilatation, and more recently, Near-Infrared Spectroscopy and Laser Speckle Contrast Analysis. Furthermore, several circulating biomarkers are commonly used in clinical research. Studies assessing endothelial function using the above techniques and biomarkers suggest that endothelial dysfunction occurs early in CKD and contributes to the target organ damage, cardiovascular events, death and progression towards end-stage kidney disease.

CONCLUSIONS

Older and newer functional methods and several biomarkers have assessed endothelial dysfunction in CKD; accumulated evidence supports an association of endothelial dysfunction with outcomes. Future research with new, non-invasive and easily applicable methods could further delineate the role of endothelial dysfunction on cardiovascular and renal disease progression in patients with CKD.

Glomerular function in relation to fine airborne particulate matter in a representative population sample

From 1990 until 2017, global air-pollution related mortality increased by 40%. Few studies addressed the renal responses to ultrafine particulate [≤ 2.5 µm (PM2.5)], including black carbon (BC), which penetrate into the blood stream. In a Flemish population study, glomerular filtration estimated from serum creatinine (eGFR) and the urinary albumin-to-creatinine ratio were measured in 2005–2009 in 820 participants (women, 50.7%; age, 51.1 years) with follow-up of 523 after 4.7 years (median). Serum creatinine, eGFR, chronic kidney disease (eGFR < 60 mL/min/1.73 m²) and microalbuminuria (> 3.5/> 2.5 mg per mmol creatinine in women/men) were correlated in individual participants via their residential address with PM_2.5 [median 13.1 (range 0.3–2.9) μg/m³] and BC [1.1 (0.3–18) μg/m³], using mixed models accounting for address clusters. Cross-sectional and longitudinally, no renal outcome was associated with PM_2.5 or BC in models adjusted for sex and baseline or time varying covariables, including age, blood pressure, heart rate, body mass index, plasma glucose, the total-to-HDL serum cholesterol ratio, alcohol intake, smoking, physical activity, socioeconomic class, and antihypertensive treatment. The subject-level geocorrelations of eGFR change with to BC and PM2.5 were 0.13 and 0.02, respectively (P ≥ 0.68). In conclusion, in a population with moderate exposure, renal function was unrelated to ultrafine particulate.

Interleukin-8 is increased in chronic kidney disease in children, but not related to cardiovascular disease

Introduction:

In this study, we aimed to detect the cytokine that is involved in the early stage of chronic kidney disease and associated with cardiovascular disease.

Methods:

We included 50 patients who were diagnosed with predialytic chronic kidney disease and 30 healthy pediatric patients in Ege University Medical Faculty Pediatric Clinic, İzmir/Turkey. Interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-13 (IL-13), and transforming grow factor-β1 (TGF-β1) levels (pg/mL) were measured by ELISA. Carotid-femoral pulse wave velocity (PWV), augmentation index (Aix), carotid intima media thickness (cIMT), and left ventricular mass index (LVMI) were evaluated as markers of cardiovascular disease. The presence of a cardiovascular disease marker was defined as an abnormality in any of the parameters (cIMT, PWV, Aix, and left ventricular mass index (SVKI)). The patient group was divided into two groups as with and without cardiovascular disease.

Results:

Mean Aix and PWV values were higher in CKD patients than controls (Aix: CKD 32.8±11.11%, healthy subjects: 6.74±6.58%, PWV CKD: 7.31±4.34m/s, healthy subjects: 3.42±3.01m/s, respectively; p=0.02, p=0.03). The serum IL-8 levels of CKD were significantly higher than of healthy subjects 568.48±487.35pg/mL, 33.67±47.47pg/mL, respectively (p<0.001). There was no statistically significant difference between IL-8, IL-10, IL-13, TGF-1, in CKD patients with and without cardiovascular disease (p> 0.05).

Discussion:

IL-8 is the sole cytokine that increases in pediatric patients with chronic kidney disease among other cytokines (IL-10, IL-13 and TGF-β1). However, we did not show that IL-8 is related to the presence of cardiovascular disease.

Review on Inflammation Markers in Chronic Kidney Disease

Chronic kidney disease (CKD) is one of the major health problems of the modern age. It represents an important public health challenge with an ever-lasting rising prevalence, which reached almost 700 million by the year 2017. Therefore, it is very important to identify patients at risk for CKD development and discover risk factors that cause the progression of the disease. Several studies have tackled this conundrum in recent years, novel markers have been identified, and new insights into the pathogenesis of CKD have been gained. This review summarizes the evidence on markers of inflammation and their role in the development and progression of CKD. It will focus primarily on cytokines, chemokines, and cell adhesion molecules. Nevertheless, further large, multicenter studies are needed to establish the role of these markers and confirm possible treatment options in everyday clinical practice.

Assessment of Endothelial and Microvascular Function in CKD: Older and Newer Techniques, Associated Risk Factors, and Relations with Outcomes

BACKGROUND

Endothelium is the inner cellular lining of the vessels that modulates multiple biological processes including vasomotor tone, permeability, inflammatory responses, hemostasis, and angiogenesis. Endothelial dysfunction, the basis of atherosclerosis, is characterized by an imbalance between endothelium-derived relaxing factors and endothelium-derived contracting factors.

SUMMARY

Starting from the semi-invasive venous occlusion plethysmography, several functional techniques have been developed to evaluate microvascular function and subsequently used in patients with CKD. Flow-mediated dilatation of the forearm is considered to be the "gold standard," while in the last years, novel, noninvasive methods such as laser speckle contrast imaging and near-infrared spectroscopy are scarcely used. Moreover, several circulating biomarkers of endothelial function have been used in studies in CKD patients. This review summarizes available functional methods and biochemical markers for the assessment of endothelial and microvascular function in CKD and discusses existing evidence on their associations with comorbid conditions and outcomes in this population. Key Messages: Accumulated evidence suggests that endothelial dysfunction occurs early in CKD and is associated with target organ damage, progression of renal injury, cardiovascular events, and mortality. Novel methods evaluating microvascular function can offer a detailed, real-time assessment of underlying phenomena and should be increasingly used to shed more light on the role of endothelial dysfunction on cardiovascular and renal disease progression in CKD.

The relationship between inflammation and neurocognitive dysfunction in obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS), a state of sleep disorder, is characterized by repetitive apnea, chronic hypoxia, oxygen desaturation, and hypercapnia. Previous studies have revealed that intermittent hypoxia (IH) conditions in OSAS patients elicited neuron injury (especially in the hippocampus and cortex), leading to cognitive dysfunction, a significant and extraordinary complication of OSAS patients. The repeated courses of airway collapse and obstruction in OSAS patients resulted in apnea and arousal during sleep, leading to IH and excessive daytime sleepiness (EDS) and subsequently contributing to the development of inflammation. IH-mediated inflammation could further trigger various types of cognitive dysfunction. Many researchers have found that, besides continuous positive airway pressure (CPAP) treatment and surgery, anti-inflammatory substances might alleviate IH-induced neurocognitive dysfunction. Clarifying the role of inflammation in IH-mediated cognitive impairment is crucial for potentially valuable therapies and future research in the related domain. The objective of this article was to critically review the relationship between inflammation and cognitive deficits in OSAS.

Metabolic abnormalities, but not obesity per se, associated with chronic kidney disease in a Taiwanese population

BACKGROUND AND AIMS

It is inconclusive whether obesity itself or metabolic abnormalities are linked to chronic kidney disease (CKD). The aim of this study was to examine the association between different subtypes of obesity and metabolic abnormalities with CKD in adults.

METHODS AND RESULTS

This study enrolled 14,983 eligible subjects stratified into metabolically healthy normal weight (MHNW), metabolically healthy overweight (MHOW), metabolically healthy obesity (MHO), metabolically unhealthy normal weight (MUNW), metabolically unhealthy overweight (MUOW), and metabolically unhealthy obesity (MUO) according to body mass index and metabolic syndrome status (ATP-III criteria). The metabolic healthy phenotype was defined as the absence of both metabolic syndrome and any known diabetes, coronary artery disease, stroke, hypertension or dyslipidemia. Early and advanced CKD were defined as eGFR<60, proteinuria, or structural abnormalities as detected by renal sonography. The prevalence of CKD was 2.5, 3.0, 4.0, 10.6, 9.5, and 10.5% in subjects with MHNW, MHOW, MHO, MUNW, MUOW, and MUO, respectively. In the multivariate analysis, the MUNW (OR:2.22, P < 0.001), MUOW (OR:2.22, P < 0.001), and MUO (OR:2.45, P < 0.001) groups were associated with early CKD. For advanced CKD, the OR was 2.56 (P < 0.001), 2.31 (P < 0.001), and 3.49 (P < 0.001) in the MUNW, MUOW, and MUO groups, respectively. The associated risks of early and advanced CKD were not significant in the MHOW and MHO group. MUOW and MUO were associated with higher risk of CKD compared with MHOW and MHO after adjusting other variables.

CONCLUSIONS

Metabolic abnormalities, but neither overweight nor obesity, were associated with a higher risk of CKD in adults.

Analysis of serum inflammatory mediators in type 2 diabetic patients and their influence on renal function

Aim

To evaluate the serum concentrations of inflammatory mediators in patients with type 2 diabetes mellitus (T2DM) with or without renal alteration (RA) function.

Methods

Serum samples from 76 patients with T2DM and 24 healthy individuals were selected. Patients with T2DM were divided into two groups according to eGFR (> or < 60mL/min/1.73m²). Cytokines, chemokines and adipokines levels were evaluated using the Multiplex immunoassay and ELISA.

Results

TNFR1 and leptin were higher in the T2DM group with RA than in the T2DM group without RA and control group. All patients with T2DM showed increased resistin, IL-8, and MIP-1α compared to the control group. Adiponectin were higher and IL-4 decreased in the T2DM group with RA compared to the control group. eGFR positively correlated with IL-4 and negatively with TNFR1, TNFR2, and leptin in patients with T2DM. In the T2DM group with RA, eGFR was negatively correlated with TNFR1 and resistin. TNFR1 was positively correlated with resistin and leptin, as well as resistin with IL-8 and leptin.

Conclusion

Increased levels of TNFR1, adipokines, chemokines and decrease of IL-4 play important role in the inflammatory process developed in T2DM and decreased renal function. We also suggest that TNFR1 is a strong predictor of renal dysfunction in patients with T2DM.

Variation of PEAR1 DNA methylation influences platelet and leukocyte function

BACKGROUND

Platelet-endothelial aggregation receptor 1 (PEAR-1) is a transmembrane receptor involved in platelet activation and megakaryopoiesis whose expression is driven by DNA methylation. PEAR1 variants were associated with differential platelet response to activation and cardiovascular outcomes. We aimed at investigating the link between PEAR1 methylation and platelet and leukocyte function markers in a family-based population.

RESULTS

We measured PEAR1 methylation in 605 Moli-family participants with available blood counts, plasma P-selectin and C-reactive protein, whole blood platelet P-selectin, and platelet-leukocyte mixed conjugate measurements. We performed principal component analysis (PCA) to identify groups of highly correlated CpG sites. We used linear mixed regression models (using age, gender, BMI, smoking, alcohol drinking, being a proband for family recruitment, being a member of myocardial infarction (MI) family as fixed effects, and family as a random effect) to evaluate associations between PEAR1 methylation and phenotypes. PEAR1 methylation Factor2, characterized by the previously identified megakaryocyte-specific CpG sites, was inversely associated with platelet-monocyte conjugates, P-selectin, and WBC counts, while positively associated with the platelet distribution width (PDW) and with leukocyte CD11b and L-selectin. Moreover, PEAR1 Factor2 methylation was negatively associated with INFLAscore, a low-grade inflammation score. The latter was partially mediated by the PEAR1 methylation effect on platelet variables. PEAR1 methylation association with WBC measurements and INFLAscore was confirmed in the independent cohort FLEMENGHO.

CONCLUSIONS

We report a significant link between epigenetic signatures in a platelet functional gene and inflammation-dependent platelet function variability measured in two independent cohorts.

Pathological Characteristics of Periodontal Disease in Patients with Chronic Kidney Disease and Kidney Transplantation

Chronic kidney disease (CKD) is recognized as an irreversible reduction of functional nephrons and leads to an increased risk of various pathological conditions, including cardiovascular disease and neurological disorders, such as coronary artery calcification, hypertension, and stroke. In addition, CKD patients have impaired immunity against bacteria and viruses. Conversely, kidney transplantation (KT) is performed for patients with end-stage renal disease as a renal replacement therapy. Although kidney function is almost normalized by KT, immunosuppressive therapy is essential to maintain kidney allograft function and to prevent rejection. However, these patients are more susceptible to infection due to the immunosuppressive therapy required to maintain kidney allograft function. Thus, both CKD and KT present disadvantages in terms of suppression of immune function. Periodontal disease is defined as a chronic infection and inflammation of oral and periodontal tissues. Periodontal disease is characterized by the destruction of connective tissues of the periodontium and alveolar bone, which may lead to not only local symptoms but also systemic diseases, such as cardiovascular diseases, diabetes, liver disease, chronic obstructive pulmonary disease, and several types of cancer. In addition, the prevalence and severity of periodontal disease are significantly associated with mortality. Many researchers pay special attention to the pathological roles and clinical impact of periodontal disease in patients with CKD or KT. In this review, we provide information regarding important modulators of periodontal disease to better understand the relationship between periodontal disease and CKD and/or KT. Furthermore; we evaluate the impact of periodontal disease on various pathological conditions in patients with CKD and KT. Moreover, pathogens of periodontal disease common to CKD and KT are also discussed. Finally, we examine the importance of periodontal care in these patients. Thus, this review provides a comprehensive overview of the pathological roles and clinical significance of periodontal disease in patients with CKD and KT.

Factors associated with a reduction in glomerular filtration rate in patients with chronic obstructive pulmonary disease

Aim. Analysis of factors associated with reduced glomerular filtration rate (GFR) in patients with chronic obstructive pulmonary disease (COPD). Materials and methods. The study included 198 patients with COPD 1-4 degrees of severity (GOLD 2014), who were on examination and treatment in Krasnodar Regional clinical hospital № 2. The control group consisted of 28 healthy volunteers, comparable in age and sex. In addition to clinical research, all patients, we calculated GFR according to the formula CKD-EPI based on cystatin C serum (GFRcys). The contribution of the factors in the risk of developing CKD was determined using multivariate linear regression analysis, as dependent variable used the value of GFRcys. Results and discussion. It was found that more than half (51.5%) of patients with COPD have a decrease in GFRcys

IL-18, VCAM-1 and P-selectin as early biomarkers in normoalbuminuric Type 2 diabetes patients

Aim: To investigate the pathophysiological role of different biomarkers in diabetic kidney disease (DKD) among normoalbuminuric patients with a low-estimated glomerular filtration rate (eGFR). Methods: In this cross-sectional study of 200 normoalbuminuric Type 2 diabetes patients, 28 patients (14%) had a low eGFR. Results: The IL-18, VCAM-1 and P-selectin levels were significantly higher at a low eGFR. On analyzing the area under the receiver operating characteristic curve, these biomarkers had significant diagnostic value and have important pathophysiological role in the progression of DKD. Conclusion: Among normoalbuminuric Type 2 diabetes patients, IL-18, VCAM-1 and P-selectin may play a significant role in the prediction of early DKD. Further prospective studies need to be conducted to confirm this observation.

Tumor necrosis factor stimulates fibroblast growth factor 23 levels in chronic kidney disease and non-renal inflammation

Fibroblast growth factor 23 (FGF23) regulates phosphate homeostasis, and its early rise in patients with chronic kidney disease is independently associated with all-cause mortality. Since inflammation is characteristic of chronic kidney disease and associates with increased plasma FGF23 we examined whether inflammation directly stimulates FGF23. In a population-based cohort, plasma tumor necrosis factor (TNF) was the only inflammatory cytokine that independently and positively correlated with plasma FGF23. Mouse models of chronic kidney disease showed signs of renal inflammation, renal FGF23 expression and elevated systemic FGF23 levels. Renal FGF23 expression coincided with expression of the orphan nuclear receptor Nurr1 regulating FGF23 in other organs. Antibody-mediated neutralization of TNF normalized plasma FGF23 and suppressed ectopic renal Fgf23 expression. Conversely, TNF administration to control mice increased plasma FGF23 without altering plasma phosphate. Moreover, in Il10-deficient mice with inflammatory bowel disease and normal kidney function, plasma FGF23 was elevated and normalized upon TNF neutralization. Thus, the inflammatory cytokine TNF contributes to elevated systemic FGF23 levels and also triggers ectopic renal Fgf23 expression in animal models of chronic kidney disease.

Predictive Role of Serum Cytokine Profiles in Acute Kidney Injury after Living Donor Liver Transplantation

Introduction

Previous studies have shown that a higher serum interleukin- (IL-) 6 level is associated with a higher risk of acute kidney injury (AKI) development after major nontransplant surgery. Our study investigated the potential association of preoperative serum cytokine profiles with new AKI development in patients who underwent living donor liver transplantation (LDLT).

Methods

Serum levels of cytokines IL-2, IL-6, IL-10, IL-12, and IL-17, interferon-γ, and tumor necrosis factor- (TNF-) α were measured in 226 LDLT recipients preoperatively and analyzed retrospectively. Recipients with a preoperative functional impairment of the kidney were excluded. AKI was defined according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria.

Results

In a univariate regression model, IL-6, IL-17, and TNF-α levels showed an association with AKI development after LDLT. Multivariate analysis showed an independent association of the preoperative serum IL-6 level with AKI development after LDLT and a significant relationship between higher serum IL-6 levels and a greater likelihood of developing AKI. Serum IL-6 levels were higher in patients with stage 3 AKI than in patients who did not develop AKI.

Conclusions

Our results support the need for further investigations of IL-6 as a predictor of AKI development in patients undergoing LDLT.