Bisphenol A analogs in patients with chronic kidney disease and dialysis therapy

Application of Nanoparticles as Novel Adsorbents in Blood Purification Strategies

BACKGROUND

Blood purification therapy for patients overloaded with metabolic toxins or drugs still needs improvement. Blood purification therapies, such as in hemodialysis or peritoneal dialysis can profit from a combined application with nanoparticles.

SUMMARY

In this review, the published literature is analyzed with respect to nanomaterials that have been customized and functionalized as nano-adsorbents during blood purification therapy. Liposomes possess a distinct combined structure composed of a hydrophobic lipid bilayer and a hydrophilic core. The liposomes which have enzymes in their aqueous core or obtain specific surface modifications of the lipid bilayer can offer appreciated advantages. Preclinical and clinical experiments with such modified liposomes show that they are highly efficient and generally safe. They may serve as indirect and direct adsorption materials both in hemodialysis and peritoneal dialysis treatment for patients with renal or hepatic failure. Apart from dialysis, nanoparticles made of specially designed metal and activated carbon have also been utilized to enhance the removal of solutes during hemoadsorption. Results are a superior adsorption capacity and good hemocompatibility shown during the treatment of patients with toxication or end-stage renal disease. In summary, nanomaterials are promising tools for improving the treatment efficacy of organ failure or toxication.

KEY MESSAGES

(i) The pH-transmembrane liposomes and enzyme-loaded liposomes are two representatives of liposomes with modified aqueous inner core which have been put into practice in dialysis. (ii) Unmodified or physiochemically modified liposomal bilayers are ideal binders for lipophilic protein-bound uremic toxins or cholestatic solutes, thus liposome-supported dialysis could become the next-generation hemodialysis treatment of artificial liver support system. (iii) Novel nano-based sorbents featuring large surface area, high adsorption capacity and decent biocompatibility have shown promise in the treatment of uremia, hyperbilirubinemia, intoxication, and sepsis. (vi) A major challenge of production lies in avoiding changes in physical and chemical properties induced by manufacturing and sterilizing procedures.

Bisphenol A and chlorinated derivatives of bisphenol A assessment in end stage renal disease patients: Impact of dialysis therapy

Patients with end stage kidney disease treated by dialysis (ESKDD) process dialysis sessions to remove molecules usually excreted by kidneys. However, dialysis therapy could also contribute to endocrine disruptors (ED) burden. Indeed, materials like dialyzer filters, ultrapure dialysate and replacement fluid could exposed ESKDD patients to Bisphenol A (BPA) and chlorinated derivatives of BPA (ClxBPAs). Thus, our aim was to compare BPA and ClxBPAs exposure between ESKDD patients, patients with stage 5 chronic kidney disease (CKD5) not dialyzed and healthy volunteers. Then we describe the impact of a single dialysis session, according to dialysis modalities (hemodialysis therapy (HD) versus online hemodiafiltration therapy (HDF)) and materials used with pre-post BPA and ClxBPAs concentrations. The plasma levels of BPA and four ClxBPAs, were assessed for 64 ESKDD patients in pre and post dialysis samples (32 treated by HD and 32 treated by HDF) in 36 CKD5 patients and in 24 healthy volunteers. BPA plasma concentrations were 22.5 times higher for ESKDD patients in pre-dialysis samples versus healthy volunteers (2.208 ± 5.525 ng/mL versus 0.098 ± 0.169 ng/mL) (p < 0.001). BPA plasma concentrations were 16 times higher for CKD5 patients versus healthy volunteers, but it was not significant (1.606 ± 3.230 ng/mL versus 0.098 ± 0.169 ng/mL) (p > 0.05). BPA plasma concentrations for ESKDD patients in pre-dialysis samples were 1.4 times higher versus CKD5 patients (2.208 ± 5.525 ng/mL versus 1.606 ± 3.230 ng/mL) (p < 0.001). For healthy volunteers, ClxBPAs were never detected, or quantified while for CKD5 and ESKDD patients one ClxBPAs at least has been detected or quantified in 14 patients (38.8%) and 24 patients (37.5%), respectively. Dialysis therapy was inefficient to remove BPA either for HD (1.983 ± 6.042 ng/mL in pre-dialysis versus 3.675 ± 8.445 ng/mL in post-dialysis) or HDF (2.434 ± 5.042 ng/mL in pre-dialysis versus 7.462 ± 15.960 ng/mL in post dialysis) regarding pre-post BPA concentrations (p > 0.05). The same result was observed regarding ClxBPA analysis. Presence of polysulfone in dialyzer fibers overexposed ESKDD patients to BPA in pre-dialysis samples with 3.054 ± 6.770 for ESKDD patients treated with a polysulfone dialyzer versus 0.708 ± 0.638 (p = 0.040) for ESKDD patients treated without a polysulfone dialyzer and to BPA in post-dialysis samples with 6.629 ± 13.932 for ESKDD patients treated with a polysulfone dialyzer versus 3.982 ± 11.004 (p = 0.018) for ESKDD patients treated without a polysulfone dialyzer. This work is to our knowledge the first to investigate, the impact of a dialysis session and materials used on BPA and ClxBPAs plasma concentrations and to compare these concentrations to those found in CKD5 patients and in healthy volunteers.

Bisphenol A (BPA) and Cardiovascular or Cardiometabolic Diseases

Bisphenol A (BPA; 4,4'-isopropylidenediphenol) is a well-known endocrine disruptor. Most human exposure to BPA occurs through the consumption of BPA-contaminated foods. Cardiovascular or cardiometabolic diseases such as diabetes, obesity, hypertension, acute kidney disease, chronic kidney disease, and heart failure are the leading causes of death worldwide. Positive associations have been reported between blood or urinary BPA levels and cardiovascular or cardiometabolic diseases. BPA also induces disorders or dysfunctions in the tissues associated with these diseases through various cell signaling pathways. This review highlights the literature elucidating the relationship between BPA and various cardiovascular or cardiometabolic diseases and the potential mechanisms underlying BPA-mediated disorders or dysfunctions in tissues such as blood vessels, skeletal muscle, adipose tissue, liver, pancreas, kidney, and heart that are associated with these diseases.

Endocrine disruptors in dialysis therapies: A literature review

Endocrine disrupting chemicals (EDCs) were defined as "an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects". These compounds are mainly eliminated by the renal route. However, patients with end-stage kidney disease treated by dialysis (ESKDD) can no longer eliminate these EDCs efficiently. Furthermore, EDCs exposure could occur via leaching from medical devices used in dialysis therapy. As a result, ESKDD patients are overexposed to EDCs. The aims of this study were to summarize EDCs exposure of ESKDD patients and to evaluate the factors at the origin of this exposure. To handle these objectives, we performed a literature review. An electronic search on PubMed, Embase and Web of science databases was performed. Twenty-six studies were finally included. The EDCs reported in these studies were Bisphenol A (BPA), Bisphenol S (BPS), Bisphenol B (BPB), Nonylphenol, Di(2-ethylhexyl) phthalate (DEHP), Di-n-butyl phthalate (DBP), and Butylbenzyl phthalate (BBP). Regarding the environment of dialysis patients, BPA, BPB, BPS, DEHP, DBP and nonylphenol have been found. Environmental exposure affects EDCs blood levels in ESKDD patients who are overexposed to BPA, BPS, BPB and DEHP. For ESKDD patients, dialyzers with housing in polycarbonate and fibers in polysulfone seem to overexpose them to BPA. Regarding dialysis therapy, peritoneal dialysis seems to decrease patient exposure vs hemodialysis therapy, and hemodiafiltration therapy seems to reduce this exposure vs hemodialysis therapy. Regarding DEHP, levels tend to increase during dialysis and when DEHP plasticizer is used in PVC devices. Finally, in the European Union a regulation on medical devices was adopted on 5 April 2017 and has been applied recently. This regulation will regulate EDCs in medical devices and thereby contribute to reconsideration of their conceptions and, finally, to reduction of ESKDD patients' exposure.

Bisphenol A and Bisphenol S in Hemodialyzers

Bisphenol A (BPA)-based materials are used in the manufacturing of hemodialyzers, including their polycarbonate (PC) housings and polysulfone (PS) membranes. As concerns for BPA's adverse health effects rise, the regulation on BPA exposure is becoming more rigorous. Therefore, BPA alternatives, such as Bisphenol S (BPS), are increasingly used. It is important to understand the patient risk of BPA and BPS exposure through dialyzer use during hemodialysis. Here, we report the bisphenol levels in extractables and leachables obtained from eight dialyzers currently on the market, including high-flux and medium cut-off membranes. A targeted liquid chromatography-mass spectrometry strategy utilizing stable isotope-labeled internal standards provided reliable data for quantitation with the standard addition method. BPA ranging from 0.43 to 32.82 µg/device and BPS ranging from 0.02 to 2.51 µg/device were detected in dialyzers made with BPA- and BPS-containing materials, except for the novel FX CorAL 120 dialyzer. BPA and BPS were also not detected in bloodline controls and cellulose-based membranes. Based on the currently established tolerable intake (6 µg/kg/day), the resulting margin of safety indicates that adverse effects are unlikely to occur in hemodialysis patients exposed to BPA and BPS quantified herein. With increasing availability of new data and information about the toxicity of BPA and BPS, the patient safety limits of BPA and BPS in those dialyzers may need a re-evaluation in the future.

Human exposure to bisphenol A (BPA) through medical-hospital devices: A systematic review

This systematic review explored the literature pertaining to patient exposure to bisphenol A (BPA) through medical-hospital devices. The acronym PICO: Patient (Medical-hospital devices), Intervention/Exposure (Bisphenol A), Comparison (Different grades of exposure) and Outcome (Assessment of exposure levels) was used. The databases used were LILACS, IBECS, MEDLINE, Capes Journal Portal, Food Science Source, FSTA and CINAHL with Full Text from EBSCO, Embase and Scopus by Elsevier, Web of Science and SCIELO. A total of 9747 references were found. After removing duplicate records, 7129 studies remained. After applying exclusion criteria and qualitative analysis, 12 articles remained. Studies have shown associations between the use of medical-hospital devices and patients' exposure to BPA. For chronic renal patients, there was an association between plasma BPA and disease severity. This review identifies that exposure to BPA is increased after the use of medical-hospital devices. More studies that address the clinical outcome of patients exposed to medical-hospital materials containing BPA are needed.

An overview of the occurrence, fate, and human risks of the bisphenol-A present in plastic materials, components, and products

With over 95% of bisphenol-A (BPA) used in the production of polycarbonate (PC) and epoxy resins, termed here as BPA-based plastic materials, components, and products (MCPs), an investigation of human exposure to BPA over the whole lifecycle of BPA-based plastic MCPs is necessary. This mini-review unpacks the implications arising from the long-term human exposure to BPA and its potential accumulation across the lifecycle of BPA-based plastics (production, use, and management). This investigation is timely and necessary in promoting a sustainable circular economy model. Restrictions of BPA in the form of bans and safety standards are often specific to products, while safety limits rely on traditional toxicological and biomonitoring methods that may underestimate human health implications and therefore the "safety" of BPA exposure. Controversies in regards to the: (a) dose-response curves; (b) the complexity of sources, release mechanisms, and pathways of exposure; and/or (c) the quality and reliability of toxicological studies, appear to currently stifle progress toward the regulation of BPA-based plastic MCPs. Due to the abundance of BPA in our MCPs production, consumption, and management systems, there is partial and inadequate evidence on the contribution of BPA-based plastic MCPs to human exposure to BPA. Yet, the production, use, and end-of-life management of plastic MCPs constitute the most critical BPA source and potential exposure pathways that require further investigation. Active collaboration among risk assessors, government, policy-makers, and researchers is needed to explore the impacts of BPA in the long term and introduce restrictions to BPA-based MCPs. Integr Environ Assess Manag 2023;19:45-62. © 2022 SETAC.

The Relationship between Typical Environmental Endocrine Disruptors and Kidney Disease

Endocrine disrupting chemicals (EDCs) are exogenous substances that alter the endocrine function of an organism, to result in adverse effects on growth and development, metabolism, and reproductive function. The kidney is one of the most important organs in the urinary system and an accumulation point. Studies have shown that EDCs can cause proteinuria, affect glomeruli and renal tubules, and even lead to diabetes and renal fibrosis in animal and human studies. In this review, we discuss renal accumulation of select EDCs such as dioxins, per- and polyfluoroalkyl substances (PFAS), bisphenol A (BPA), and phthalates, and delineate how exposures to such EDCs cause renal lesions and diseases, including cancer. The regulation of typical EDCs with specific target genes and the activation of related pathways are summarized.

Relationship between emergent BPA-substitutes and renal and cardiovascular diseases in adult population

Plastic waste pollution is one of the leading environmental problems of modern society. Its use, disposal, and recycling lead to the release of xenobiotic compounds such as bisphenol A (BPA), a known endocrine disruptor related to numerous pathologies. Due to the new restrictions on its use, it is gradually being replaced by derived molecules, such as bisphenol F or S (BPF or BPS), whose health risks have not yet been adequately studied. In the present work, significant relationships between the new BPA substitute molecules and renal and cardiovascular diseases have been detected by performing binomial and multinomial logistic regressions in one of the world's largest cohorts of urinary phenols. The results have shown a significant relationship between urinary BPF and renal function or heart disease (specifically congestive heart failure). Urinary BPS has shown a positive relationship with the risk of hypertension and a negative relationship with kidney disease. Consequently, applying new substitute molecules could imply potential health risks equivalent to BPA.

Bisphenol A impairs renal function by reducing Na+/K+-ATPase and F-actin expression, kidney tubule formation in vitro and in vivo

The kidney proximal tubule is responsible for reabsorbing water and NaCl to maintain the homeostasis of the body fluids, electrolytes, and nutrients. Thus, abnormal functioning of the renal proximal tubule can lead to life-threatening imbalances. Bisphenol A (BPA) has been used for decades as a representative chemical in household plastic products, but studies on its effects on the kidney proximal tubule are insufficient. In this study, immunocytochemical and cytotoxicity tests were performed using two- and three-dimensional human renal proximal tubular epithelial cell (hRPTEC) cultures to investigate the impact of low-dose BPA (1-10 μM) exposure. BPA was found to interfere with straight tubule formation as observed by low filamentous actin formation and reduced Na⁺/K⁺-ATPase expression in the tubules of hRPTEC 3D cultures. Similar results were observed in rat pup kidneys following oral administration of 250 mg/kg BPA. Moreover, the expression of HO-1 and 8-OHdG, key markers for oxidative stress, was increased in vitro and in vivo following BPA administration, whereas that of OAT1 and OAT, important transporters of the renal proximal tubules, was not altered. Overall, no-observed-adverse-effect-level (NOAEL)-dose BPA exposure can decrease renal function by promoting abnormal tubular formation both in vitro and in vivo. Therefore, we propose that although it does not exhibit life-threatening toxicity, exposure to low levels of BPA can negatively affect homeostasis in the body by means of long-term deterioration of renal proximal tubular function in humans.

Strategies to Protect Dialysis Patients against Bisphenol A

Bisphenol A (BPA), also known as 2,2,-bis(4-hydroxyphenyl) propane, is a common component of plastics worldwide. However, it has been shown to act as an endocrine disruptor with some hormonal functions. Furthermore, high levels of BPA have been related to the development of cardiovascular events and the activation of carcinogenesis pathways. Patients with chronic kidney disease (CKD) have higher serum concentrations of BPA due to their impaired renal function. This situation is aggravated in CKD patients requiring dialysis, because the BPA content of dialysis devices (such as, for example, the filters) is added to the lack of excretion. In addition to the development of BPA-free dialysis filters, some techniques can contribute to the reduction of BPA levels in these patients. The aim of this review is to illustrate the impact of BPA on dialysis patients and suggest some strategies to reduce its inherent risks.

Bisphenol a Exposure and Kidney Diseases: Systematic Review, Meta-Analysis, and NHANES 03-16 Study

Bisphenol A (BPA) is a compound that is especially widespread in most commonly used objects due to its multiple uses in the plastic industry. However, several data support the need to restrict its use. In recent years, new implications of BPA on the renal system have been discovered, which denotes the need to expand studies in patients. To this end, a systematic review and a meta-analysis was performed to explore existing literature that examines the BPA-kidney disease paradigm and to determine what and how future studies will need to be carried out. Our systematic review revealed that only few relevant publications have focused on the problem. However, the subsequent meta-analysis revealed that high blood concentrations of BPA could be a factor in developing kidney disease, at least in people with previous pathologies such as diabetes or hypertension. Furthermore, BPA could also represent a risk factor in healthy people whose urinary excretion is higher. Finally, the data analyzed from the NHANES 03-16 cohort provided new evidence on the possible involvement of BPA in kidney disease. Therefore, our results underline the need to carry out a thorough and methodologically homogeneous study, delving into the relationship between urinary and blood BPA, glomerular filtration rate, and urine albumin-to-creatinine ratio, preferably in population groups at risk, and subsequently in the general population, to solve this relevant conundrum with critical potential implications in Public Health.

Bisphenol A Modulates Autophagy and Exacerbates Chronic Kidney Damage in Mice

BACKGROUND

Bisphenol A (BPA) is a ubiquitous environmental toxin that accumulates in chronic kidney disease (CKD). Our aim was to explore the effect of chronic exposition of BPA in healthy and injured kidney investigating potential mechanisms involved.

METHODS

In C57Bl/6 mice, administration of BPA (120 mg/kg/day, i.p for 5 days/week) was done for 2 and 5 weeks. To study BPA effect on CKD, a model of subtotal nephrectomy (SNX) combined with BPA administration for 5 weeks was employed. In vitro studies were done in human proximal tubular epithelial cells (HK-2 line).

RESULTS

Chronic BPA administration to healthy mice induces inflammatory infiltration in the kidney, tubular injury and renal fibrosis (assessed by increased collagen deposition). Moreover, in SNX mice BPA exposure exacerbates renal lesions, including overexpression of the tubular damage biomarker Hepatitis A virus cellular receptor 1 (Havcr-1/KIM-1). BPA upregulated several proinflammatory genes and increased the antioxidant response [Nuclear factor erythroid 2-related factor 2 (Nrf2), Heme Oxygenase-1 (Ho-1) and NAD(P)H dehydrogenase quinone 1 (Nqo-1)] both in healthy and SNX mice. The autophagy process was modulated by BPA, through elevated autophagy-related gene 5 (Atg5), autophagy-related gene 7 (Atg7), Microtubule-associated proteins 1A/1B light chain 3B (Map1lc3b/Lc3b) and Beclin-1 gene levels and blockaded the autophagosome maturation and flux (p62 levels). This autophagy deregulation was confirmed in vitro.

CONCLUSIONS

BPA deregulates autophagy flux and redox protective mechanisms, suggesting a potential mechanism of BPA deleterious effects in the kidney.

The association between urinary BPA levels and medical equipment among pediatric intensive care patients

We aim to evaluate urinary total BPA (tBPA) levels and association with medical devices used on patients in pediatric intensive care units. This cross-sectional descriptive study included 117 critically ill children. Urinary tBPA levels were determined using high-performance liquid chromatography. General estimating equations with repeated measures analyzed the effect of interventions and devices on urinary BPA levels. A total of 292 urine samples taken from 117 child intensive care patients were studied. When age, sex, and body mass index-for age z-scores were controlled, cases having endotracheal intubation showed higher urinary tBPA levels (p = 0.003) and hemodialyzed patients had considerably higher urinary tBPA levels (p = 0.004). When confounding factors were controlled, cases using both multiple iv treatment and more than four medical devices showed higher urinary tBPA levels than their counterparts (p = 0.007 and p = 0.028, respectively). The use of certain medical devices and interventions could increase BPA exposure in pediatric intensive care patients.

Bisphenol S is a haemodialysis-associated xenobiotic that is less toxic than bisphenol A

BACKGROUND

Bisphenol S (BPS) is a structural analogue of bisphenol A (BPA) that is found in the environment. BPS may accumulate in anuric patients due to decreased urinary excretion. The toxicity and health effects of BPS are poorly characterized.

METHODS

A cross-over study was performed using polynephron (PN) or polysulphone (PS) dialysers for a short (1 week each, 14 patients) or long (3 months each, 20 patients) period on each dialyser. Plasma BPA, BPS and hippuric acid were assessed by SRM mass spectrometry (SRM-MS). The biological significance of the BPS concentrations found was explored in cultured kidney tubular cells.

RESULTS

In haemodiafiltration (HDF) patients, plasma BPS was 10-fold higher than in healthy subjects (0.53 ± 0.52 versus 0.05 ± 0.01 ng/mL; P = 0.0015), while BPA levels were 35-fold higher (13.23 ± 14.65 versus 0.37 ± 0.12 ng/mL; P = 0.007). Plasma hippuric acid decreased after an HDF session, while BPS and BPA did not. After 3 months of HDF with the same membranes, the BPS concentration was 1.01 ± 0.87 ng/mL for PN users and 0.62 ± 0.21 ng/mL for PS users (P non-statistically significant). In vitro, BPS and BPA leaked from dialysers containing them. In cultured tubular cells, no biological impact (cytotoxicity, inflammatory and oxidative stress gene expression) was observed for BPS up to 200 µM, while BPA was toxic at concentrations ≥100 µM.

CONCLUSIONS

BPS may be released from dialysis membranes, and dialysis patients display high BPS concentrations. However, BPS concentrations are lower than BPA concentrations and no BPS toxicity was observed at concentrations found in patient plasma.

Linoleic acid-modified liposomes for the removal of protein-bound toxins: An in vitro study

INTRODUCTION

Protein-bound uremic toxins (PBUTs) and liver failure-related cholestatic solutes are associated with adverse outcomes in patients with chronic kidney disease (CKD) and liver failure, respectively, and are not easily removed by traditional dialysis therapies. We constructed linoleic acid-modified liposomes (LA-liposomes) as indirect adsorbent in the dialysate, and evaluated their effects on the clearance of the representative PBUTs and cholestatic solutes.

METHODS

The LA-liposomes were prepared by the thin-film hydration method. The binding rates of liposomes and protein-bound solutes were detected by the ultrafiltration column. The in vitro dialysis experiments were performed using both non-current and current devices to assay the clearing efficiency of the dialysate supported by LA-liposomes.

RESULTS

The LA-liposomes exhibited good binding properties to the PBUTs, bilirubin and bile acids. The LA-liposome dialysate showed higher solute reduction rates of the representative PBUTs and cholestatic solutes than the traditional dialysate or dialysate supported by the unmodified plain liposomes. Also, albumin binding of the PBUTs was significantly inhibited by the addition of linoleic acid (LA), and the removal efficiency of PBUTs was greatly enhanced by the combination of indirect adsorbent LA-liposomes and LA as the competitive displacer.

CONCLUSION

LA-liposomes were efficient in the clearance of the representative PBUTs and liver failure-related solutes. Moreover, the combination of indirect adsorbent LA-liposomes and competitive displacer suggested a potential application for the extremely highly-bound solutes.