Associations among chronic kidney disease, high total p-cresylsulfate and left ventricular systolic dysfunction

Advances in the Progression and Prognosis Biomarkers of Chronic Kidney Disease

Chronic kidney disease (CKD) is one of the increasingly serious public health concerns worldwide; the global burden of CKD is increasingly due to high morbidity and mortality. At present, there are three key problems in the clinical treatment and management of CKD. First, the current diagnostic indicators, such as proteinuria and serum creatinine, are greatly interfered by the physiological conditions of patients, and the changes in the indicator level are not synchronized with renal damage. Second, the established diagnosis of suspected CKD still depends on biopsy, which is not suitable for contraindication patients, is also traumatic, and is not sensitive to early progression. Finally, the prognosis of CKD is affected by many factors; hence, it is ineviatble to develop effective biomarkers to predict CKD prognosis and improve the prognosis through early intervention. Accurate progression monitoring and prognosis improvement of CKD are extremely significant for improving the clinical treatment and management of CKD and reducing the social burden. Therefore, biomarkers reported in recent years, which could play important roles in accurate progression monitoring and prognosis improvement of CKD, were concluded and highlighted in this review article that aims to provide a reference for both the construction of CKD precision therapy system and the pharmaceutical research and development.

Associations among total p-cresylsulfate, indoxyl sulfate and hippuric acid levels with hemodialysis quality indicators in maintenance hemodialysis patients

BACKGROUND

Total p-cresylsulfate (PCS), indoxyl sulfate (IS) and hippuric acid (HA) are harmful uremic toxins known to be elevated in patients with uremia. Serum total PCS, IS and HA levels have been associated with coronary atherosclerosis, left ventricular hypertrophy, metabolic acidosis, neurological symptoms, and accelerated renal damage associated with chronic kidney disease; however, no study has examined the effect of total PCS, IS and HA on hemodialysis (HD) quality indicators. The aim of this study was to examine associations among total PCS, IS and HA with HD quality indicators in patients undergoing HD treatment.

METHODS

This study included 264 consecutive patients at a single HD center who assessed using previously demonstrated HD quality indicators including anemia, bone-mineral metabolism, dialysis dose, cardiovascular risk, and middle molecule removal area. Serum HA was measured using a capillary electrophoresis method. Serum total PCS and IS concentrations were measured using an Ultra Performance LC System.

RESULTS

Multiple regression analysis showed that sex, potassium, systolic blood pressure (SBP), average BP, β2-microglobulin, and creatinine were independently positively associated with IS level, and that age, total cholesterol, and estimated glomerular filtration rate (eGFR) was independently negatively associated with IS level. In addition, β2-microglobulin was independently positively associated with total PCS. Moreover, potassium, diastolic blood pressure, average BP, β2-microglobulin, dialysis vintage, and albumin were independently positively associated with HA level, and age, transferrin saturation, fasting glucose, and eGFR were independently negatively associated with HA level. When the patients were stratified by age and sex, serum IS and HA levels were still independently associated with some hemodialysis quality indicators. In addition, canonical correlation analysis also confirmed the relationship between uremic toxins (IS and HA) and HD quality indicators (potassium, β2-microglobulin, average BP, creatinine, and eGFR).

CONCLUSION

This study demonstrated that uremic toxins (IS and HA) and HD quality indicators (potassium, β2-microglobulin, average BP, creatinine, and eGFR) constructs were correlated with each other, and that there were sex and age differences in these associations among maintenance HD patients.

Circulating hepassocin level in patients with stable angina is associated with fatty liver and renal function

Background: Chronic kidney disease (CKD) is a major risk factor for coronary artery disease and it is often associated with hepatic steatosis. Hepassocin (also known as hepatocyte-derived fibrinogen related protein or fibrinogen-like 1) is a novel hepatokine that causes hepatic steatosis and induces insulin resistance. However, the role of hepassocin in renal function status remains unclear. Our objective was to investigate the association of plasma hepassocin level with fatty liver and renal function status in patients with stable angina. Methods: Plasma hepassocin levels were determined by enzyme-linked immunosorbent assays in 395 consecutive patients with stable angina. Renal function was defined as an estimated glomerular filtration rate (eGFR). Fatty liver was defined by ultrasonography and fibrosis-4 (FIB-4) index. Results: With increasing hepassocin tertiles, patients had higher prevalence of fatty live, an increased waist-to-hip ratio, and neutrophil count, monocyte count, and FIB-4 index, higher levels of uric acid, blood urine nitrogen and higher sensitivity C-reactive protein. They also had incrementally lower eGFR, serum hemoglobin and albumin levels. In multiple linear stepwise regression analysis, only eGFR was significantly independent negatively associated with plasma hepassocin levels. Conclusion: Our results indicate that circulating hepassocin in patients with stable angina is associated with fatty liver and renal function, which suggests that increased plasma hepassocin may be involved in the pathogenesis of fatty liver and CKD.

The gut microbiota and its relationship with chronic kidney disease

Chronic kidney disease (CKD) is a worldwide health problem, because it is one of the most common complications of metabolic diseases including obesity and type 2 diabetes. Patients with CKD also develop other comorbidities, such as hypertension, hyperlipidemias, liver and cardiovascular diseases, gastrointestinal problems, and cognitive deterioration, which worsens their health. Therapy includes reducing comorbidities or using replacement therapy, such as peritoneal dialysis, hemodialysis, and organ transplant. Health care systems are searching for alternative treatments for CKD patients to mitigate or retard their progression. One new topic is the study of uremic toxins (UT), which are excessively produced during CKD as products of food metabolism or as a result of the loss of renal function that have a negative impact on the kidneys and other organs. High urea concentrations significantly modify the microbiota in the gut also, cause a decrease in bacterial strains that produce anti-inflammatory and fuel molecules and an increase in bacterial strains that can metabolize urea, but also produce UT, including indoxyl sulfate and p-cresol sulfate. UT activates several cellular processes that induce oxidative environments, inflammation, proliferation, fibrosis development, and apoptosis; these processes mainly occur in the gut, heart, and kidney. The study of the microbiota during CKD allowed for the implementation of therapy schemes to try to reduce the circulating concentrations of UT and reduce the damage. The objective of this review is to show an overview to know the main UT produced in end-stage renal disease patients, and how prebiotics and probiotics intervention acts as a helpful tool in CKD treatment.

Association between fibre intake and indoxyl sulphate/P-cresyl sulphate in patients with chronic kidney disease: Meta-analysis and systematic review of experimental studies

BACKGROUND AND OBJECTIVE

Indoxyl sulphate (IS) and p-cresyl sulphate (PCS), which are difficult to excrete adequately out of the body, are closely related to the progression of chronic kidney disease (CKD) and various deuteropathy. Better than peritoneal dialysis (PD) and haemodialysis (HD), dietary fibre has been considered to reduce IS and PCS levels. In view of the absence of formal recommendations on fibre intake in CKD nutritional guidelines, we conducted this meta-analysis to assess the effects of dietary fibre on IS and PCS for CKD patients.

METHODS

The effects were pooled and expressed in terms of weighted mean difference (WMD) with 95% confidence interval (95% CI). Q test and I² statistics were used to assess the heterogeneity.

RESULTS

A total of 12 relevant estimates from 7 reports, including 203 CKD patients, showed that dietary fibre significantly reduced their PCS level (WMD = -16.160, 95% CI: -23.824, -8.495).

CONCLUSIONS

The meta-analysis produced a strong corroboration that dietary fibre intake does have a good therapeutic effect on patients with CKD. The conclusions need to be validated by randomised controlled experiments (RCT) with better design, larger samples, longer course of treatment and higher quality.

Circulating secreted frizzled-related protein 5 and chronic kidney disease in patients with acute ST-segment elevation myocardial infarction

Secreted frizzled-related protein-5 (Sfrp5) known as secreted antagonist binds to Wnt protein. It has been shown to be downregulated by histone acetylation and promoter methylation, and to function as a tumor suppressor gene by inducing apoptosis in renal cell cancer cells. However, its relationship with chronic kidney disease (CKD) has not been well studied. Our objective was to investigate the effect of plasma Sfrp5 levels in subjects with and without CKD. Plasma Sfrp5 levels were determined by enzyme-linked immunosorbent assays in 196 consecutive patients with acute ST-segment elevation myocardial infarction (STEMI). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m². For the purpose of this study, stage 1 or 2 CKD patients (eGFR ≥ 60 ml/min per 1.73 m²) were classified as not having CKD. With increasing Sfrp5 tertiles, the patients had higher frequencies of hypertension, stage 4 or 5 CKD, and waist-to-hip ratio, incrementally lower eGFRs and serum hemoglobin levels, and higher levels of blood urine nitrogen (BUN), creatinine, and adiponectin. Multivariate logistic regression analysis showed that an increased plasma Sfrp5 level was independently associated with CKD for all subjects (adjusted odds ratio (OR), 1.08; 95% confidence interval (CI), 1.02-1.14; p = 0.011). Sfrp5 was also significantly positively related to BUN, creatinine, and adiponectin, and significantly negatively related to eGFR and hemoglobin. When the patients were stratified by age, plasma Sfrp5 level was independently related to CKD for patients >65 years old (adjusted OR, 1.10; 95% CI, 1.00-1.20; p = 0.045), however, the association was not significant for those <65 years old. In addition, Sfrp5 was significantly positively related to BUN, creatinine, and adiponectin, and significantly negatively related to eGFR and hemoglobin in patients >65 years old. Our results suggest that Sfrp5 may play a role in the pathogenesis of CKD in acute STEMI patients who are older than 65 years.

Protein-bounded uremic toxin p-cresylsulfate induces vascular permeability alternations

The goal of the present studies is to investigate that the impact of p-cresylsulfate (PCS) on the endothelial barrier integrity via in situ exposure and systemic exposure. Vascular permeability changes induced by local injection of PCS were evaluated by the techniques of both Evans blue (EB) and India ink tracer. Rats were intravenously injected with EB or India ink followed by intradermal injections of various doses of PCS (0, 0.4, 2, 10 and 50 µmol/site) on rat back skins. At different time points, skin EB was extracted and quantified. The administration of India ink was used to demonstrate leaky microvessels. Skin PCS levels were also determined by liquid chromatography-mass spectrometry. We also investigated whether the increased endothelial leakage occurred in the aortic endothelium in rats treated with 5/6 nephrectomy and intraperitoneal injection of PCS 50 mg/kg/day for 4 weeks. The aortic endothelial integrity was evaluated by increased immunoglobulin G (IgG) leakage. High doses of PCS, but not lower doses, significantly induced vascular leakage as compared to saline injection and EB leakage exhibited in time-dependent manner. A time-correlated increase in leaky microvessels was detected in the tissues examined. The injected PCS declined with time and displayed an inverse relationship with vascular leakage. Chronic kidney disease (CKD) rats administered with PCS, compared to control rats, had significantly higher serum levels of PCS and apparent IgG deposition in the aortic intima. Increased endothelial leakage induced by PCS in skin microvessels and the aorta of CKD rats suggests that the PCS-induced endothelial barrier dysfunction.

p-Cresyl Sulfate

If chronic kidney disease (CKD) is associated with an impairment of kidney function, several uremic solutes are retained. Some of these exert toxic effects, which are called uremic toxins. p-Cresyl sulfate (pCS) is a prototype protein-bound uremic toxin to which many biological and biochemical (toxic) effects have been attributed. In addition, increased levels of pCS have been associated with worsening outcomes in CKD patients. pCS finds its origin in the intestine where gut bacteria metabolize aromatic amino acids, such as tyrosine and phenylalanine, leading to phenolic end products, of which pCS is one of the components. In this review we summarize the biological effects of pCS and its metabolic origin in the intestine. It appears that, according to in vitro studies, the intestinal bacteria generating phenolic compounds mainly belong to the families Bacteroidaceae, Bifidobacteriaceae, Clostridiaceae, Enterobacteriaceae, Enterococcaceae, Eubacteriaceae, Fusobacteriaceae, Lachnospiraceae, Lactobacillaceae, Porphyromonadaceae, Staphylococcaceae, Ruminococcaceae, and Veillonellaceae. Since pCS remains difficult to remove by dialysis, the gut microbiota could be a future target to decrease pCS levels and its toxicity, even at earlier stages of CKD, aiming at slowing down the progression of the disease and decreasing the cardiovascular burden.

The burden of major adverse cardiac events in patients with coronary artery disease

Background

Patients with a history of cardiovascular disease are at high risk of developing secondary major adverse cardiac events (MACE). This study aimed to identify independent predictors of MACE after hospital admission which could be used to identify of high-risk patients who may benefit from preventive strategies.

Methods

This study included 1,520 consecutive patients with coronary artery disease (CAD) (654 with acute coronary syndrome (ACS) and 866 with elective percutaneous coronary intervention (PCI) patients) who received PCI and/or stenting. MACE was defined as all-cause mortality or rehospitalization for a cardiovascular- related illness. Cardiovascular-related illnesses included heart failure, reinfarction (nonfatal), recurrence of angina pectoris and repeat PCI or coronary artery bypass graft.

Results

During a mean follow-up period of 32 months, 558 of the 1,520 patients developed at least one MACE. Cox regression analysis showed that the baseline clinical and biochemical variables which associated with MACE were age, being illiterate, a widow or widower, and/or economically dependent, having triple vessel disease, stent implantation, anemia, and/or diabetes mellitus, waist to hip ratio (WHR), diastolic blood pressure, fasting glucose, total cholesterol, high-density lipoprotein cholesterol (HDL-C), creatinine, estimated glomerular filtration rate (eGFR), red blood cell count, hemoglobin, hematocrit, and mean corpuscular-hemoglobin concentration (MCHC) in ACS patients, and age, malnourished, and/or economically dependent, taking hypoglycemic medication, having triple vessel disease, stent implantation, anemia, diabetes mellitus, and/or hypertension, WHR, fasting glucose, HDL-C, uric acid, creatinine, eGFR, high-sensitivity C-reactive protein, mean corpuscular volume, and MCHC in elective PCI patients. Using multivariate Cox regression analysis, we found the MACE’s independent factors are triple vessel disease, stent implantation, hypertension, and eGFR in ACS patients, and having triple vessel disease, stent implantation, hypertension, and uric acid in elective PCI patients.

Conclusions

Having triple vessel disease, stent implantation, hypertension, and eGFR or uric acid independently predicted MACE in patients with CAD after long-term follow-up. Fortunately, these factors are modifiable and should be identified and monitored early.