Elevated interleukin-12 and interleukin-18 in chronic kidney disease are not associated with arterial stiffness

Renoprotective Potency of Sitagliptin versus Pioglitazone in Type 2 Diabetic Patients: Impact on LncMIAT

Background: Diabetes mellitus (DM) represents one of the most important reasons for chronic kidney diseases due to the high level of blood glucose that destructs blood vessels. Objective: The present study focused on investigating the protective impact of sitagliptin on kidney complication in type 2 diabetes mellitus (T2DM) patients in comparison to pioglitazone to examine which has the superior effect against the nephritic complication of DM. Methods: Eighty adult subjects were classified into four groups: control group, pioglitazone-treated T2DM patients (P group), sitagliptin-treated T2DM patients for less than one year (SL group), and sitagliptin-treated T2DM patients for more than one year (SM group). Blood samples were withdrawn from all subjects for analysis of neutrophil gelatinase-associated lipocalin (NGAL), vanin-1, kidney injury molecule-1 (KIM-1), glyoxalase-1 (Glo-1), methylglyoxal (MG), cystatin-C, and interleukin-18 (IL-18) using competitive ELISA kits. Also, long noncoding myocardial infarction associated transcript (lncMIAT) was measured in whole blood using qRT-PCR. Results: The present study revealed that the lncMIAT expression level was significantly higher in the P group as compared to the SL group, SM group, or healthy control group. Additionally, serum NGAL, vanin-1, KIM-1, Glo-1, MG, and cystatin-C were significantly higher in the P group and SL group as compared to the SM group and healthy control group. Conclusion: Sitagliptin protected the kidney through downregulation of lncMIAT besides amelioration of kidney injury marker levels, which was more preferable than in pioglitazone therapy.

Cytokines and their role in cardiovascular diseases

The evaluation of diagnostic and prognostic biomarkers has always been a hot topic in various diseases. Considering that cardiovascular diseases (CVDs) have the highest mortality and morbidity rates in the world, various studies have been conducted so far to find CVD associated biomarkers, including cardiac troponin (cTn) and NT-proBNP. Cytokines are components of the immune system that are involved in the pathogenesis of CVD due to their contribution to the inflammation process. The level of cytokines varies in many cardiovascular diseases. For instance, the plasma level of IL-1α, IL-18, IL-33, IL-6 and IL-8 is positively correlated with atherosclerosis and that of some other interleukins such as IL-35 is negatively correlated with acute myocardial infarction or cardiac angina. Due to its pivotal role in the inflammation process, IL-1 super family is involved in many CVDs, including atherosclerosis. IL-20 among the interleukins of IL-10 family has a pro-atherogenic role, while others, such as IL-10 and IL-19, play an anti-atherogenic role. In the present review, we have collected the latest published evidence in this respect to discuss valuable cytokines from the diagnostic and prognostic stand point in CVDs.

Chronic heat stress induces renal fibrosis and mitochondrial dysfunction in laying hens

BACKGROUND

Heat stress in laying hens negatively affects egg production and shell quality by disrupting the homeostasis of plasma calcium and phosphorus levels. Although the kidney plays an important role in calcium and phosphorus homeostasis, evidence regarding the effect of heat stress on renal injury in laying hens is yet to be elucidated. Therefore, the aim of this study was to evaluate the effects of chronic heat stress on renal damage in hens during laying periods.

METHODS

A total of 16 white-leghorn laying hens (32 weeks old) were randomly assigned to two groups (n = 8). One group was exposed to chronic heat stress (33 °C for 4 weeks), whereas the other group was maintained at 24 °C.

RESULTS

Chronic heat exposure significantly increased plasma creatinine and decreased plasma albumin levels (P < 0.05). Heat exposure also increased renal fibrosis and the transcription levels of fibrosis-related genes (COLA1A1, αSMA, and TGF-β) in the kidney. These results suggest that renal failure and fibrosis were induced by chronic heat exposure in laying hens. In addition, chronic heat exposure decreased ATP levels and mitochondrial DNA copy number (mtDNA-CN) in renal tissue, suggesting that renal mitochondrial dysfunction occurs under conditions of heat stress. Damaged mitochondria leak mtDNAs into the cytosol and mtDNA leakage may activate the cyclic GMP-AMP synthase (cGAS) stimulator of interferon genes (STING) signaling pathway. Our results showed that chronic heat exposure activated the cGAS-STING pathway as indicated by increased expression of MDA5, STING, IRF7, MAVS, and NF-κB levels. Furthermore, the expression of pro-inflammatory cytokines (IL-12) and chemokines (CCL4 and CCL20) was upregulated in heat-stressed hens.

CONCLUSIONS

These results suggest that chronic heat exposure induces renal fibrosis and mitochondrial damage in laying hens. Mitochondrial damage by heat stress may activate the mtDNA-cGAS-STING signaling and cause subsequent inflammation, which contributes to the progression of renal fibrosis and dysfunction.

Association between periodontitis and chronic kidney disease

Periodontitis and chronic kidney disease are chronic conditions with high community prevalence across the world. Patients with chronic kidney disease have been noted to have a high burden of periodontitis, and several shared risk factors have been associated with the prevalence and severity of both conditions. However, the precise relationship between the two conditions, and the extent to which each may contribute to the development of the other, remains a matter of debate. The goals of the present work were to: (a) provide the most current and relevant literature overview of the association between periodontitis and chronic kidney disease; (b) explore mechanisms underlying this association; and (c) determine if evidence exists for an independent association between these conditions. We also assessed whether improved oral hygiene and periodontal treatment could reduce the risk of developing chronic kidney disease and, if so, what protocols these strategies involve. Finally, we aimed to reveal gaps in our current knowledge to delineate the directions of future research. Although the exact relationship between these two conditions has not yet been defined, we highlight the importance of the interprofessional interaction between dental practitioners and the nephrology team and the importance of oral health assessment in the management of chronic kidney disease.

Early renal and vascular damage within the normoalbuminuria condition

OBJECTIVE

A continuous association between albuminuria and cardiorenal risk exists further below moderately increased albuminuria ranges. If only based in albumin to creatinine ratio (ACR) higher than 30 mg/g, a significant percentage of individuals may be out of the scope for therapeutic management. Despite epidemiological outcomes, the identification of biochemical changes linked to early albuminuria is underexplored, and normoalbuminuric individuals are usually considered at no risk in clinical practice. Here, we aimed to identify early molecular alterations behind albuminuria development.

METHODS

Hypertensive patients under renin-angiotensin system (RAS) suppression were classified as control, (ACR < 10 mg/g) or high-normal (ACR = 10-30 mg/g). Urinary protein alterations were quantified and confirmed by untargeted and targeted mass spectrometry. Coordinated protein responses with biological significance in albuminuria development were investigated. Immunohistochemistry assays were performed in human kidney and arterial tissue to in situ evaluate the associated damage.

RESULTS

A total of 2663 identified proteins reflect inflammation, immune response, ion transport and lipids metabolism (P value ≤ 0.01). A1AT, VTDB and KNG1 varied in high-normal individuals (P value < 0.05), correlated with ACR and associated with the high-normal condition (odds ratio of 20.76, 6.00 and 7.04 were found, respectively (P value < 0.001)). After 12 months, protein variations persist and aggravate in progressors to moderately increased albuminuria. At tissue level, differential protein expression was found in kidney from individuals with moderately increased albuminuria and atherosclerotic aortas for the three proteins, confirming their capacity to reflect subclinical organ damage.

CONCLUSION

Early renal and vascular damage is molecularly evidenced within the normoalbuminuria condition.

Applying Proteomics and Integrative "Omics" Strategies to Decipher the Chronic Kidney Disease-Related Atherosclerosis

Patients with chronic kidney disease (CKD) are at increased risk of atherosclerosis and premature mortality, mainly due to cardiovascular events. However, well-known risk factors, which promote "classical" atherosclerosis are alone insufficient to explain the high prevalence of atherosclerosis-related to CKD (CKD-A). The complexity of the molecular mechanisms underlying the acceleration of CKD-A is still to be defied. To obtain a holistic picture of these changes, comprehensive proteomic approaches have been developed including global protein profiling followed by functional bioinformatics analyses of dysregulated pathways. Furthermore, proteomics surveys in combination with other "omics" techniques, i.e., transcriptomics and metabolomics as well as physiological assays provide a solid ground for interpretation of observed phenomena in the context of disease pathology. This review discusses the comprehensive application of various "omics" approaches, with emphasis on proteomics, to tackle the molecular mechanisms underlying CKD-A progression. We summarize here the recent findings derived from global proteomic approaches and underline the potential of utilizing integrative systems biology, to gain a deeper insight into the pathogenesis of CKD-A and other disorders.

Lanthionine, a Novel Uremic Toxin, in the Vascular Calcification of Chronic Kidney Disease: The Role of Proinflammatory Cytokines

Vascular calcification (VC) is a risk factor for cardiovascular events and mortality in chronic kidney disease (CKD). Several components influence the occurrence of VC, among which inflammation. A novel uremic toxin, lanthionine, was shown to increase intracellular calcium in endothelial cells and may have a role in VC. A group of CKD patients was selected and divided into patients with a glomerular filtration rate (GFR) of <45 mL/min/1.73 m² and ≥45 mL/min/1.73 m². Total Calcium Score (TCS), based on the Agatston score, was assessed as circulating lanthionine and a panel of different cytokines. A hemodialysis patient group was also considered. Lanthionine was elevated in CKD patients, and levels increased significantly in hemodialysis patients with respect to the two CKD groups; in addition, lanthionine increased along with the increase in TCS, starting from one up to three. Interleukin IL-6, IL-8, and Eotaxin were significantly increased in patients with GFR < 45 mL/min/1.73 m² with respect to those with GFR ≥ 45 mL/min/1.73 m². IL-1b, IL-7, IL-8, IL-12, Eotaxin, and VEGF increased in calcified patients with respect to the non-calcified. IL-8 and Eotaxin were elevated both in the low GFR group and in the calcified group. We propose that lanthionine, but also IL-8 and Eotaxin, in particular, are a key feature of VC of CKD, with possible marker significance.

Effect of Maternal Dietary Redox Levels on Antioxidative Status and Immunity of the Suckling Off-Spring

This study investigates two levels of dietary selenium (Se) and vitamin E in combination on their status in sows and their progeny, and influence on antioxidant status and immunological responses of the piglets at weaning. Female pigs (n = 6) were provided LOW or HIGH antioxidant nutrition (Se and vitamin E) from mating until weaning of their off-spring. The HIGH treatment elevated the concentration of Se (p = 0.015) and α-tocopherol (p = 0.023) in plasma of piglets compared with piglets of the LOW treatment. Treatments also affected the concentrations of milk and sow plasma immunoglobulins. Piglets from sows on the HIGH treatment had increased (p < 0.001) activity of glutathione peroxidase, lower serum levels of C-reactive protein (p = 0.005), haptoglobin (p = 0.05) and albumin (p = 0.05), and the number of white blood cells (p = 0.023) and the ratio of NEU to LYM was lower (p = 0.025) than in piglets from sows on the LOW group. Furthermore, the dietary antioxidant level influenced responses of cytokines (interleukine (IL) 6 (p = 0.007), 12 (p = 0.01) and 18 (p = 0.01)) in piglets’ plasma. In conclusion, improved antioxidant status via dietary maternal provision improves the robustness of the offspring via immunomodulatory mechanisms.

Biomarkers of Inflammation and Glomerular Filtration Rate in Individuals with Recent-Onset Type 1 and Type 2 Diabetes

CONTEXT

While inflammation has been associated with kidney function in long-standing diabetes, its possible association in newly diagnosed diabetes is unknown.

OBJECTIVE

To investigate cross-sectional and prospective associations between biomarkers of inflammation and kidney function in recent-onset diabetes.

METHODS

The study included individuals with type 1 and type 2 diabetes with known diabetes duration of <1 year from the German Diabetes Study. Baseline serum concentrations of 74 biomarkers were measured using proximity extension assay technology and their associations with estimated glomerular filtration rate (eGFR) and kidney function decline over 5 years were tested using multiple linear and logistic regression analysis.

RESULTS

The cross-sectional analysis included 165 individuals with type 1 diabetes and 291 with type 2 diabetes. Baseline eGFR was higher in type 1 compared with type 2 diabetes (102 ± 15 vs 90 ± 16 mL/min/1.73 m2; P < 0.0001). After full adjustment for covariates and multiple testing, 7 biomarkers were associated with lower baseline eGFR in type 1 diabetes and 24 were associated with lower baseline eGFR in type 2 diabetes. Among these biomarkers, 6 biomarkers (CD5, CCL23, CST5, IL-10RB, PD-L1, TNFRSF9) were inversely associated with eGFR in both diabetes types. The prospective analysis did not detect associations between inflammatory biomarkers and kidney function decline. No evidence of an interaction between diabetes type and inflammatory biomarkers was found.

CONCLUSION

Several biomarkers of inflammation associate with lower baseline eGFR in recent-onset type 1 and type 2 diabetes, but do not associate with kidney function loss during the first 5 years after the diagnosis of diabetes.

Aortic Pulse Wave Velocity in Peritoneal Dialysis Patients Is Not Simply Associated with Extracellular Water Expansion

BACKGROUND

Cardiac death is increased in peritoneal dialysis (PD) patients. Pulse wave velocity (PWV) is a measurement of arterial stiffness, and previous reports linked PWV to increased extracellular water (ECW). As cyclers and icodextrin are increasingly used, we wished to determine whether this association between PWV and ECW remains.

METHODS

We measured aortic PWV (aPWV) and bioimpedance (InBody, Seoul, South Korea) in consecutive PD patients attending for peritoneal membrane testing.

RESULTS

189 patients were included, 62.4% male, mean age 63.1 ± 15.2 years, 45.3% diabetic, median dialysis duration 12.3 (6.5-25.1) months, 71.4% using cyclers, weight 73.0 ± 16.1 kg, systolic blood pressure 142 ± 21 mm Hg, aPWV 10.4 ± 5.1 m/s. aPWV was associated with pulse pressure (r = 0.26, p = 0.001), Davies comorbidity score (r = 0.18, p = 0.013), and N-terminal pro-brain-type natriuretic peptide (NTproBNP; r = 0.18, p = 0.011). Patients with aPWV ≥10 m/s were older (65.9 ± 13.6 vs. 60.1 ± 16.3 years, p < 0.01) with a higher ECW-to-total body water ratio (0.400 ± 0.012 vs. 0.396 ± 0.013, p < 0.05), but ECW/height was not different (8.52 ± 2.32 vs. 8.75 ± 1.78 L/m), as was NTproBNP (2,472 [788-5,422] vs. 1,234 [410-6,230] ng/L). On multivariable testing, aPWV was positively associated with β-blocker prescription (standardised β coefficient [Stβ] 0.3, 95% confidence limits [95% CL] 0.7-2.6, p = 0.001) and negatively with icodextrin prescription (Stβ 0.19, 95% CL -0.2 to -2.1, p = 0.04).

CONCLUSIONS

Compared to previous studies, we did not find an independent association between aPWV and ECW and estimates of ECW excess, using the InBody bioimpedance device, suggesting that vascular stiffness in PD patients is more complex than simple ECW volume expansion in PD patients.

Inflammation-Related Patterns in the Clinical Staging and Severity Assessment of Chronic Kidney Disease

Chronic kidney disease (CKD) is an irreversible loss of kidney function, and it represents a major global public health burden due to both its prevalence and its continuously increasing incidence. Mineral bone disorders (MBDs) constitute a hallmark of CKD, and alongside cardiovascular complications, they underlie a poor prognosis for these patients. Thus, our study focused on novel CKD biomarker patterns and their impact on the clinical staging of the disease. As a first testing approach, the relative expression levels of 105 proteins were assessed by the Proteome Profiler Cytokine Array Kit for pooled CKD stage 2–4 serum samples to establish an overall view regarding the proteins involved in CKD pathogenesis. Among the molecules that displayed significant dysregulation in the CKD stages, we further explored the involvement of Dickkopf-related protein 1 (Dkk-1), a recognised inhibitor of the Wnt signalling pathway, and its crosstalk with 1,25OH₂D₃ (calcitriol) as new players in renal bone and vascular disease. The serum levels of these two molecules were quantified by an ELISA (76 samples), and the results reveal decreasing circulating levels of Dkk-1 and calcitriol in advanced CKD stages, with their circulating expression showing a downward trend as the CKD develops. In the next step, we analysed the inflammation and MBD biomarkers' expression in CKD (by xMAP array). Our results show that the molecules involved in orchestrating the inflammatory response, interleukin-6 (IL-6) and tumour necrosis factor alpha (TNFα), as well as the mineral biomarkers osteoprotegerin (OPG), osteocalcin (OC), osteopontin (OPN), and fibroblast growth factor 23 (FGF-23), correlate with Dkk-1 and calcitriol, raising the possibility of them being potential useful CKD biomarkers. These results reveal the impact of different biomarker patterns in CKD staging and severity, thus opening up novel approaches to be explored in CKD clinical management.

The Effects of OMEGA-3 Fatty Acid Supplementation Upon Interleukin-12 and Interleukin-18 in Chronic Kidney Disease Patients

OBJECTIVE(S)

Cardiovascular disease (CVD) remains a leading cause of mortality in chronic kidney disease (CKD) patients. Interventions targeting traditional risk factors have largely proven ineffective in CKD patients in part because of the increased role of nontraditional risk factors such as chronic inflammation. Omega-3 fatty acids (ω3FA) are inexpensive and safe natural agents, which target inflammation and have potential cardioprotective benefits. The aim of the study was to determine the effects of ω3FA supplementation upon serum interleukin (IL)-12, IL-18, and highly sensitive C-reactive protein (hsCRP) in patients with Stage 3-4 CKD.

METHODS

We performed a post-hoc analysis of a randomized placebo-controlled trial in 73 nondiabetic CKD patients to determine the effects of ω3FA supplementation (4 g daily for 8 weeks) upon serum levels of IL-12, IL-18, and hsCRP.

RESULTS

There were no preintervention differences in IL-12, IL-18, or hsCRP between treatment groups. Postintervention levels of IL-12, IL-18, and hsCRP were similar between the treatment groups. However, IL-12 and IL-18 increased in both treatment groups over the intervention period, whereas hsCRP remained unchanged. The magnitude of increase in serum IL-18 (ΔIL-18) was significantly less in participants in the ω3FA treatment group compared to placebo (P = .047).

CONCLUSION(S)

This study has shown that 4 g daily ω3FA supplementation may lower serum IL-18 levels in patients with moderate CKD. Although there were no apparent effects on several other markers of inflammation, this study provides evidence for a specific effect of ω3FA on inflammatory pathways.

Relationship between pulse pressure and inflammation with left ventricular diastolic dysfunction in chronic kidney disease patients

BACKGROUND

Diastolic dysfunction (DD) is an important cause of cardiovascular disease (CVD) mortality in chronic kidney disease (CKD) patients. Non-traditional risk factors, such as arterial stiffness and inflammation, are implicated in the pathogenesis of DD in CKD patients.

AIM

To determine the association between inflammatory markers (interleukin (IL)-12, IL-18, highly sensitive C-reactive protein (hsCRP)) and non-invasive markers of arterial stiffness (24-h pulse pressure (PP)) with DD in stages 3-4 CKD patients.

METHODS

We performed a sub-analysis of 78 non-diabetic stages 3-4 CKD subjects to determine the relationship between 24-h PP, IL-12, IL-18 and hsCRP with DD.

RESULTS

DD was present in 38 subjects (49%). Subjects with DD were significantly older (61.0 ± 1.9 vs 50.2 ± 2.0 years; P < 0.001) and had higher 24-h PP (48(95% confidence interval 45, 52) vs 43(95% confidence interval 41, 45) mmHg; P < 0.005); 24-h PP was associated with DD (P = 0.02), but this was no longer significant after adjustment for age (P = 0.31). Serum IL-12, IL-18 and hsCRP levels were not significantly different between subjects with or without DD.

CONCLUSION

Asymptomatic subclinical DD was present in 50% of a cohort of stages 3-4 CKD patients but was not associated with IL-12, IL-18 or hsCRP. The association between 24-h PP and DD was no longer apparent following adjustment for age, but given the small sample size, our findings will need to be explored in larger-sized cohorts of individuals with moderate-stage CKD.

Interleukin-12 and its procoagulant effect on erythrocytes, platelets and fibrin(ogen): the lesser known side of inflammation

Inflammation, with its associated inflammatory molecules, is integral to most chronic diseases, including the various cardiovascular diseases. Interleukin 12 (IL12) is one of the inflammatory cytokines that is upregulated during inflammation; however, we know very little about its exact effect on red blood cells (RBCs), platelets and fibrin(ogen). IL12 is an important pleiotropic cytokine in early inflammatory responses and has potent immunomodulatory, antitumour and anti-infection activity. Here we investigate how low levels of circulating IL12, comparable to levels found during chronic inflammation, affect coagulation parameters, platelets and RBCs. We used thromboelastography, scanning electron microscopy, refractometery and wide-field microscopy. Our results show that IL12 caused hypercoagulation, platelet activation and spreading, as well as RBC agglutination. This phenomenon has far-reaching implications for treatment of the plethora of conditions where IL12 is upregulated, since it suggests aberrant haemorheology as agglutination affects blood flow. This information might be used in future to target the lowering of IL12 in inflammatory conditions, as well as address RBC agglutination.

Increased Inflammatory Response in Association with the Initiation of Hemodialysis Compared with Peritoneal Dialysis in a Prospective Study of End-Stage Kidney Disease Patients

BACKGROUND

Large epidemiological studies have demonstrated an early survival advantage with the initiation of peritoneal dialysis (PD) compared to haemodialysis (HD). Chronic inflammation may contribute to atherosclerosis and cardiovascular (CVD) mortality in end-stage kidney disease (ESKD). We hypothesize that the initiation of HD in ESKD patients is associated with a greater inflammatory response compared with PD.

AIMS

To examine the effects of initiating HD and PD upon inflammation and CVD risk markers in ESKD patients.

METHODS

We performed a pilot prospective study on 75 predialysis CKD stage-5 subjects comparing the effects of HD and PD upon high sensitivity C-reactive protein (hsCRP), interleukin(IL)-12, IL-18 and pulse wave velocity (PWV). Study visits were conducted 3 - 6 months before (baseline) and after (follow-up) initiation of dialysis RESULTS: Thirty-nine and 36 patients were initiated on HD and PD respectively. HD patients were older than PD patients (65.1 ± 2.1 vs 57.7 ± 2.7 years; p = 0.03) but had similar baseline systolic blood pressure (SBP), pulse pressure (PP), hsCRP, IL-12, IL-18, and PWV. At follow-up, HD patients had significantly increased hsCRP levels [5.2(3.7, 7.3) vs 1.7(1.0, 2.8)g/L; p < 0.001] compared to PD. Follow-up blood pressure, IL-12, IL-18, and PWV were similar between groups. A significant association remained between hsCRP and HD after adjustment for age, previous CVD, and residual urine output.

CONCLUSION

The initiation of HD was associated with significantly increased hsCRP compared to PD. Further study is required to determine the plausibility of inflammation as a potential underlying contributor to the observed early mortality difference between dialysis modalities.

Inflammatory Markers for Arterial Stiffness in Cardiovascular Diseases

Arterial stiffness predicts an increased risk of cardiovascular events. Inflammation plays a major role in large arteries stiffening, related to atherosclerosis, arteriosclerosis, endothelial dysfunction, smooth muscle cell migration, vascular calcification, increased activity of metalloproteinases, extracellular matrix degradation, oxidative stress, elastolysis, and degradation of collagen. The present paper reviews main mechanisms explaining the crosstalk between inflammation and arterial stiffness and the most common inflammatory markers associated with increased arterial stiffness, considering the most recent clinical and experimental studies. Diverse studies revealed significant correlations between the severity of arterial stiffness and inflammatory markers, such as white blood cell count, neutrophil/lymphocyte ratio, adhesion molecules, fibrinogen, C-reactive protein, cytokines, microRNAs, and cyclooxygenase-2, in patients with a broad variety of diseases, such as metabolic syndrome, diabetes, coronary heart disease, peripheral arterial disease, malignant and rheumatic disorders, polycystic kidney disease, renal transplant, familial Mediterranean fever, and oral infections, and in women with preeclampsia or after menopause. There is strong evidence that inflammation plays an important and, at least, partly reversible role in the development of arterial stiffness, and inflammatory markers may be useful additional tools in the assessment of the cardiovascular risk in clinical practice. Combined assessment of arterial stiffness and inflammatory markers may improve non-invasive assessment of cardiovascular risk, enabling selection of high-risk patients for prophylactic treatment or more regular medical examination. Development of future destiffening therapies may target pro-inflammatory mechanisms.

IL-33 and ST2 levels in chronic kidney disease: Associations with inflammation, vascular abnormalities, cardiovascular events, and survival

Objective

Increased inflammation, associated with the increase in chronic kidney disease (CKD) stage, has a very important influence in vascular injury and cardiovascular diseases. In this study, we aimed to investigate the levels of IL-33 and ST2 in the different stages of CKD and to determine their effect on vascular damage and cardiovascular events (CVE).

Methods

This was an observational cohort study in which serum IL-33 and ST2 were obtained from 238 CKD (stages 1–5) patients. We examined the changes in IL-33/ST2 levels in CKD patients, as well as the association with a surrogate of endothelial dysfunction. Fatal and non-fatal CVE were recorded for a mean of 24 months. We also performed a COX regression analysis to determine the association of IL-33/ST2 levels with CVE and survival.

Results

IL-33 and ST2 levels were significantly increased and estimated glomerular filtration rates (eGFR) were decreased. Flow-mediated dilatation (FMD) was significantly decreased from stage 1 to stage 5 CKD. IL-33 and ST2 levels were associated with FMD, and ST2 was a predictor. Multivariate Cox analysis showed that the presence of diabetes mellitus, smoking, and proteinuria and haemoglobin, Hs-CRP, IL-33, and ST2 were associated with the risk of CVE. Kaplan-Meier survival curves showed that patients with IL-33 and ST2 levels below the median value (IL-33 = 132.6 ng/L, ST2 = 382.9 pg/mL) had a higher cumulative survival compared with patients who had IL-33 and ST2 levels above the median value (log-rank test, p = 0.000).

Conclusion

This is the first study that demonstrates that serum IL-33 and ST2 are associated with vascular injury, cardiovascular events, and survival in CKD patients.

Diagnostic Value of Urine Tissue Inhibitor of Metalloproteinase-2 and Insulin-Like Growth Factor-Binding Protein 7 for Acute Kidney Injury: A Meta-Analysis

Background

Tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein-7 (IGFBP7) are both involved in renal tubular epithelial cell cycle arrest in acute kidney injury (AKI). Several recent studies showed that urine TIMP-2 times IGFBP7 ([TIMP-2]*[IGFBP7]) is a promising biomarker to predict AKI.

Methods

The aim of this meta-analysis was to assess the diagnostic value of urine [TIMP-2]*[IGFBP7] for early diagnosis of AKI. Relevant studies were retrieved from the PubMed, EMBASE, and Cochrane Library databases. The sensitivity and specificity were determined, and summary receiver operating characteristic (SROC) curves were constructed.

Results

Ten full-text prospective studies were included in this meta-analysis. The estimated sensitivity of urine [TIMP-2]*[IGFBP7] for the early diagnosis of AKI was 0.84 (95% CI = 0.80–0.88) and the specificity was 0.57 (95%CI = 0.55–0.60). The SROC analysis showed an area under the curve of 0.8813.

Limitation

The limited number of included studies, small sample size, unpublished negative results and language limitation might have affected the evaluation.

Conclusion

Urine [TIMP-2]*[IGFBP7] is a promising candidate for early detection of AKI, especially in ruling-out AKI. However, the potential of this biomarker should be validated in larger studies with a broader spectrum of clinical settings.

Interleukin-18 increases TLR4 and mannose receptor expression and modulates cytokine production in human monocytes

Interleukin-18 is a proinflammatory cytokine belonging to the interleukin-1 family of cytokines. This cytokine exerts many unique biological and immunological effects. To explore the role of IL-18 in inflammatory innate immune responses, we investigated its impact on expression of two toll-like receptors (TLR2 and TLR4) and mannose receptor (MR) by human peripheral blood monocytes and its effect on TNF-α, IL-12, IL-15, and IL-10 production. Monocytes from healthy donors were stimulated or not with IL-18 for 18 h, and then the TLR2, TLR4, and MR expression and intracellular TNF-α, IL-12, and IL-10 production were assessed by flow cytometry and the levels of TNF-α, IL-12, IL-15, and IL-10 in culture supernatants were measured by ELISA. IL-18 treatment was able to increase TLR4 and MR expression by monocytes. The production of TNF-α and IL-10 was also increased by cytokine treatment. However, IL-18 was unable to induce neither IL-12 nor IL-15 production by these cells. Taken together, these results show an important role of IL-18 on the early phase of inflammatory response by promoting the expression of some pattern recognition receptors (PRRs) that are important during the microbe recognition phase and by inducing some important cytokines such as TNF-α and IL-10.

Cardiovascular risk markers associated with arterial calcification in patients with chronic kidney disease Stages 3 and 4

Background

The contribution of pro-inflammatory markers to cardiovascular (CV) risk and vascular calcification in chronic kidney disease (CKD) remains largely to be elucidated. We investigated the association between plasma levels of several biomarkers and calcification volume in three different vascular beds in CKD Stages 3 and 4 patients.

Methods

This is a cross-sectional, exploratory study in patients with an estimated glomerular filtration rate (eGFR) ≥20 and ≤45 mL/min/1.73 m² and serum phosphorus ≥3.5 and <6.0 mg/dL enrolled in a previously published randomized, double blind, placebo-controlled single-centre trial. Ethylenediaminetetraacetic acid (EDTA) plasma samples were collected at baseline before patients received study medication and analysed for the presence of a number of biomarkers. Coronary artery calcium (CAC), thoracic aortic calcification (TAC) and abdominal aortic calcification (AAC) volumes were measured using standard electron-beam computed tomography protocols. Associations were adjusted for age, sex, smoking, body mass index, diabetes mellitus status, low-density lipoprotein cholesterol (LDL-C), systolic blood pressure and eGFR.

Results

Associations with CAC were found for β2-microglobulin (B2M), fibroblast growth factor 23 (FGF23), interleukin-8 (IL-8) and IL-18. AAC was associated with: B2M, FGF23 and IL-2 receptor alpha (IL-2 RA). TAC was associated with: B2M, FGF23, IL-2 RA, IL-18 and tumour necrosis factor receptor type I. For most of the analysed biomarkers, there were non-significant trends of associations with calcification.

Conclusions

This exploratory study found that elevated plasma levels of several inflammatory biomarkers are significantly associated with arterial calcification in CKD Stages 3 and 4 patients. A greater understanding of inflammation and calcification in CKD patients may help the development of CV risk-assessment algorithms for better management of these patients.