Early-life exposure to bisphenol A and reproductive-related outcomes in rodent models: a systematic review and meta-analysis

Prostatic morphological changes throughout life: Cytochemistry as a tool to reveal tissue aging markers

The prostate undergoes normal or pathological morphological changes throughout life. An understanding of these changes is fundamental for the comprehension of aging-related pathological processes such as benign prostatic hyperplasia (BPH) and cancer. In the present study, we show some of these morphological changes, as well as histochemical techniques like Weigert's resorcin-fuchsin method, Picrosirius Red, and Gömöri's reticulin for use as tools in the study of prostate tissue under light microscopy. For this purpose, prostates of the Mongolian gerbil (n = 9), an experimental model that develops BPH spontaneously, were analyzed at three life stages: young (1 month old), adult (3 months old), and old (15 months old). The results showed that fibrillar components such as collagen, and reticular and elastic fibers, change throughout life. In young animals, the prostate has cuboidal epithelium surrounded by thin layers of smooth muscle, continuous collagen fibers, winding reticular fibers, and sporadic elastic fibers. With adulthood, the epithelium becomes columnar, encircled by compacted muscle cells among slender collagen fibers, elongated reticular fibers, and linear elastic fibers. In aging individuals, the prostate's epithelium stratifies, surrounded by thick muscle layers among dense collagen fibers, disordered reticular fibers, and elastic fibers in different planes. We also identified a few accumulations of lipid droplets and lipofuscin granules in adult animals and high accumulation in old animals evidenced by Oil red O and Gömöri-Halmi techniques, respectively. The histochemical techniques presented here have been demonstrated to be useful and accessible tools in prostate studies. RESEARCH HIGHLIGHTS: Cytochemical techniques to study prostate morphology. The prostate changes with age.

Prognostic and immunotherapeutic significance of immunogenic cell death-related genes in colon adenocarcinoma patients

In recent years, genes associated with immunogenic cell death (ICD)-related genes have garnered significant interest as potential targets for immunotherapy. As a frontier in cancer treatment, immunotherapy has notably enhanced the therapeutic outcomes for cancer patients. However, since only a subset of patients benefits from this treatment approach, there is an imperative need for biomarker research to enhance patient sensitivity to immunotherapy. Expression of ICD-related genes and clinical patient data were sourced from The Cancer Genome Atlas (TCGA) database. Utilizing univariate Cox regression analysis, we constructed a signature for predicting the overall survival of colon adenocarcinoma (COAD) patients. A genomic feature analysis was performed, incorporating tumor mutation burden (TMB) and copy number variation (CNV). The immunological characteristics were analyzed via the ssGSEA and GSEA algorithms, with the resulting data visualized using R software (version 4.2.1). According to the univariate regression analysis for COAD, AIM2 emerged as the gene most significantly associated with overall survival among the 32 ICD-related genes in the TCGA dataset. Patients were divided into two groups based on high or low AIM2 expression, and genomic differences between the groups were explored. Patients expressing high levels of AIM2 had a higher TMB and a lower CNV. In addition, these patients had elevated immune checkpoint, immune cell, and immune function scores, thus indicating increased sensitivity to immunotherapy. TIDE analysis further confirmed that these patients were likely to respond more effectively to immunotherapy. Subclass mapping analysis corroborated our findings, demonstrating that patients with high AIM2 expression responded more positively to immunotherapy. Additionally, our study found that the suppression of AIM2 could significantly enhance the proliferation, invasion, and migration capabilities of colon cancer cells. In this research, we identified a novel prognostic signature suggesting that patients with higher AIM2 expression levels are more likely to respond favorably to immunotherapy.

Identification of DUSP7 as an RNA Marker for Prognostic Stratification in Acute Myeloid Leukemia: Evidence from Large Population Cohorts

Background

The problem of prognostic stratification in acute myeloid leukemia (AML) patients still has limitations.

Methods

The expression profile data and clinical features of AML patients were obtained from multiple publicly available sources, including GSE71014, TCGA-LAML, and TARGET-AML. Single-cell analysis was performed using the TISCH project. All the analysis was conducted in the R software.

Results

In our study, three public AML cohorts, GSE71014, TARGET-AML, and TCGA-AML, were selected. Then, we identified the prognosis-related molecules through bioinformatic analysis. Finally, the DUSP7 was noticed as a risk factor for AML patients, which has not been reported previously. Biological enrichment analysis and immune-related analysis were performed to illustrate the role of DUSP7 in AML. Single-cell analysis indicated that the DUSP7 was widely distributed in various cells, especially in monocyte/macrophages and malignant. Following this, a prognosis model based on DUSP7-derived genes was constructed, which showed a good prognosis prediction ability in all cohorts.

Conclusions

Our results preliminarily reveal the role and potential mechanism of DUSP7 in AML, providing direction for future research.

Integrative analysis illustrates the role of PCDH7 in lung cancer development, cisplatin resistance, and immunotherapy resistance: an underlying target

Background: Cisplatin resistance is a common clinical problem in lung cancer. However, the underlying mechanisms have not yet been fully elucidated, highlighting the importance of searching for biological targets. Methods: Bioinformatics analysis is completed through downloaded public data (GSE21656, GSE108214, and TCGA) and specific R packages. The evaluation of cell proliferation ability is completed through CCK8 assay, colony formation, and EdU assay. The evaluation of cell invasion and migration ability is completed through transwell and wound-healing assays. In addition, we evaluated cell cisplatin sensitivity by calculating IC50. Results: Here, we found that PCDH7 may be involved in cisplatin resistance in lung cancer through public database analysis (GSE21656 and GSE108214). Then, a series of in vitro experiments was performed, which verified the cancer-promoting role of PCDH7 in NSCLC. Moreover, the results of IC50 detection showed that PCDH7 might be associated with cisplatin resistance of NSCLC. Next, we investigated the single-cell pattern, biological function, and immune analysis of PCDH7. Importantly, we noticed PCDH7 may regulate epithelial-mesenchymal transition activity, and the local infiltration of CD8+ T and activated NK cells. Furthermore, we noticed that patients with high PCDH7 expression might be more sensitive to bortezomib, docetaxel, and gemcitabine, and resistant to immunotherapy. Finally, a prognosis model based on three PCDH7-derived genes (GPX8, BCAR3, and TNS4) was constructed through a machine learning algorithm, which has good prediction ability on NSCLC patients' survival. Conclusion: Our research has improved the regulatory framework for cisplatin resistance in NSCLC and can provide direction for subsequent related research, especially regarding PCDH7.

Development and Validation of the Promising PPAR Signaling Pathway-Based Prognostic Prediction Model in Uterine Cervical Cancer

A ligand-activated transcription factor, peroxisome proliferator-activated receptor (PPAR) regulates fatty acid uptake and transport. In several studies, upregulation of PPAR expression/activity by cancer cells has been associated with cancer progression. Worldwide, cancer of the cervix ranks fourth among women's cancers. Angiogenesis inhibitors have improved treatment for recurrent and advanced cervical cancer since their introduction 5 years ago. In spite of that, the median overall survival rate for advanced cervical cancer is 16.8 months, indicating that treatment effectiveness is still lacking. Thus, it is imperative that new therapeutic methods be developed. In this work, we first downloaded the PPAR signaling pathway-related genes from the previous study. In addition, the single-sample gene set enrichment analysis (ssGSEA) algorithm was applied to calculate the PPAR score of patients with cervical cancer. Furthermore, cervical cancer patients with different PPAR scores show different sensitivity to immune checkpoint therapy. In order to screen the genes to serve as the best biomarker for cervical cancer patients, we then construct the PPAR-based prognostic prediction model. The results revealed that PCK1, MT1A, AL096855.1, AC096711.2, FAR2P2, and AC099568.2 not only play a key role in the PPAR signaling pathway but also show good predictive value in cervical cancer patients. The gene set variation analysis (GSVA) enrichment analysis also proved that the PPAR signaling pathway is one of the most enriched pathways in the prognostic prediction model. Finally, further analysis revealed that AC099568.2 may be the most promising biomarker for the diagnosis, treatment, and prognosis in cervical cancer patients. Both the survival analysis and Receiver Operating Characteristic curve demonstrated that AC099568.2 plays a key role in cervical cancer patients. However, to our knowledge, this is the first time a study focused on the role of AC099568.2 in cervical cancer patients. Our work successfully revealed a new biomarker for cervical cancer patients, which also provides a new direction for future research.

Investigation of Underlying Biological Association and Targets between Rejection of Renal Transplant and Renal Cancer

Background

Post-renal transplant patients have a high likelihood of developing renal cancer. However, the underlying biological mechanisms behind the development of renal cancer in post-kidney transplant patients remain to be elucidated. Therefore, this study aimed to investigate the underlying biological mechanism behind the development of renal cell carcinoma in post-renal transplant patients.

Methods

Next-generation sequencing data and corresponding clinical information of patients with clear cell renal cell carcinoma (ccRCC) were obtained from The Cancer Genome Atlas Program (TCGA) database. The microarray data of kidney transplant patients with or without rejection response was obtained from the Gene Expression Omnibus (GEO) database. In addition, statistical analysis was conducted in R software.

Results

We identified 55 upregulated genes in the transplant patients with rejection from the GEO datasets (GSE48581, GSE36059, and GSE98320). Furthermore, we conducted bioinformatics analyses, which showed that all of these genes were upregulated in ccRCC tissue. Moreover, a prognosis model was constructed based on four rejection-related genes, including PLAC8, CSTA, AIM2, and LYZ. The prognosis model showed excellent performance in prognosis prediction in a ccRCC cohort. In addition, the machine learning algorithms identified 19 rejection-related genes, including PLAC8, involved in ccRCC occurrence. Finally, the PLAC8 was selected for further research, including its clinical and biological role.

Conclusion

In all, our study provides novel insight into the transition from the rejection of renal transplant to renal cancer. Meanwhile, PLAC8 could be a potential biomarker for ccRCC diagnosis and prognosis in post-kidney transplant patients.

Hyperthermia intravesical chemotherapy acts as a promising alternative to bacillus Calmette-Guérin instillation in non-muscle-invasive bladder cancer: a network meta-analysis

Introduction

With the shortage of bacillus Calmette-Guérin (BCG) vaccine, it is important to find an alternative to BCG instillation, which is the most commonly used adjuvant treatment for non-muscle-invasive bladder cancer (NMIBC) patients after transurethral resection of bladder tumor treatment (TURBt) to delay tumor recurrence. Hyperthermia intravesical chemotherapy (HIVEC) with mitomycin C (MMC) is a potential treatment choice. We aim to compare HIVEC with BCG instillation for the preventive efficacy of bladder tumor recurrence and progression.

Methods

A network meta-analysis (NMA) was taken with MMC instillation and TURBt as the attached comparators. Randomized controlled trials (RCTs) with NIMBC patients after TURBt were included. Articles with pure BCG unresponsive patients and combined therapies were excluded. The study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO, CRD42023390363).

Results

It was found that HIVEC had a non-significant 22% relative reduction in bladder tumor recurrence compared with BCG instillation [HIVEC vs. BCG: HR 0.78, 95% credible interval (CrI) 0.55-1.08] and a nonsignificant higher risk of bladder tumor progression (BCG vs. HIVEC: HR 0.77, 95% CrI 0.22-3.03).

Discussion

HIVEC is a potential alternative to BCG, and it is expected to be the standard therapy for NMIBC patients after TURBt during the global shortage of BCG.

Systematic Review Registration

PROSPERO identifier, CRD42023390363.

Identifying potential targets for lung cancer intervention by analyzing the crosstalk of cancer-associated fibroblasts and immune and metabolism microenvironment

BACKGROUND

Cancer-associated fibroblasts (CAFs) have been reported to play a crucial role in the tumor microenvironment and progression.

METHODS

The data used in this study were obtained from the Cancer Genome Atlas and Gene Expression Omnibus databases, and all analyses were performed using R software.

RESULTS

We first quantified the CAFs infiltration through single sample gene set enrichment analysis in the TCGA and combined GEO cohort (GSE30219, GSE37745, and GSE50081). Our result showed that patients with high levels of CAF infiltration were associated with worse clinical features and poor prognosis. Immune microenvironment analysis indicated that high CAF infiltration might result in increased infiltration of immune cells, including aDC, B cells, CD8+ T cells, cytotoxic cells, DC, eosinophils, iDC, macrophages, mast cells, neutrophils, NK CD56dim cells, NK cells, pDC, and T cells. Correlation analysis showed a significant positive correlation between CAFs and M2 macrophages, while a negative correlation was found between CAFs and glycerophospholipid metabolism. Kaplan-Meier survival curves indicated that glycerophospholipid metabolism was a protective factor against lung cancer. Biological enrichment analysis showed that pathways such as allograft rejection, epithelial-mesenchymal transition, KRAS signaling, TNF-α signaling, myogenesis, IL6/JAK/STAT3 signaling, IL2/STAT5 signaling were upregulated in the patients with high CAF infiltration. Moreover, patients with high CAF infiltration had a lower proportion of immunotherapy responders. Genome analysis showed that low CAFs infiltration was associated with high genome instability. We identified FGF5 and CELF3 as key genes involved in the interaction between CAFs, M2 macrophages, and glycerophospholipid metabolism, and further analyzed FGF5. In vitro experiments showed that FGF5 promoted the proliferation, invasion and migration of lung cancer cells and was primarily localized in the nucleoli fibrillar center.

CONCLUSIONS

Our study provides novel insights into the roles of CAFs in lung cancer progression and the underlying crosstalk of tumor metabolism and immune microenvironment.

Urinary concentration of phthalates and bisphenol A during minipuberty is associated with reproductive hormone concentrations in infant boys

BACKGROUND

The transient postnatal activation of the hypothalamic-pituitary-gonadal hormone axis is termed minipuberty and considered an important developmental period, which is highly sensitive to endocrine disruption. Here, we explore exposure-outcome associations during minipuberty between concentrations of potentially endocrine disrupting chemicals (EDCs) in urine of infant boys and their serum reproductive hormone concentrations.

METHODS

In total, 36 boys participating in the COPENHAGEN Minipuberty Study had data available for both urine biomarkers of target endocrine disrupting chemicals and reproductive hormones in serum from samples collected on the same day. Serum concentrations of reproductive hormones were measured by immunoassays or by LC-MS/MS. Urinary concentrations of metabolites of 39 non-persisting chemicals, including phthalates and phenolic compounds, were measured by LC-MS/MS. Nineteen chemicals had concentrations above the limit of detection in ≥50% of children and were included in data analysis. Associations of urinary phthalate metabolite and phenol concentrations (in tertiles) with hormone outcomes (age- and sex-specific SD-scores) were analysed by linear regression. Primarily, we focused on the EU regulated phthalates; butylbenzyl phthalate (BBzP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di-(2-ethylhexyl) phthalate (DEHP) as well as bisphenol A (BPA). Urinary metabolites of DiBP, DnBP and DEHP were summed and expressed as ∑DiBPm, ∑DnBPm and ∑DEHPm.

RESULTS

Compared to boys in the lowest ∑DnBPm tertile, urinary concentration of ∑DnBPm was associated with concurrent higher luteinizing hormone (LH) and anti-Müllerian hormone (AMH) SD-scores as well as lower testosterone/LH ratio in boys in the middle ∑DnBPm tertile (estimates (CI 95%) 0.79 (0.04; 1.54), 0.91 (0.13; 1.68), and -0.88 (-1.58;-0.19), respectively). Further, higher insulin-like peptide 3 (INSL3) SD-scores and lower DHEAS SD-score in boys in the highest ∑DnBPm tertile (0.91 (0.12; 1.70) and -0.85 (-1.51;-0.18), respectively) were observed. In addition, boys in the middle and highest ∑DEHPm tertile had higher LH (1.07 (0.35; 1.79) and 0.71 (-0.01; 1.43), respectively) and in the highest ∑DEHPm tertile also higher AMH (0.85 (0.10; 1.61)) concentration SD-scores, respectively. Boys in the highest BPA tertile had significantly higher AMH and lower DHEAS concentration compared to boys in the lowest BPA tertile (1.28 (0.54; 2.02) and -0.73 (-1.45; -0.01)), respectively.

DISCUSSION

Our findings indicate that exposure to chemicals with known or suspected endocrine disrupting potential, especially the EU-regulated DnBP, DEHP and BPA, may modify male reproductive hormone concentrations in infant boys suggesting that minipuberty is a critical window sensitive to endocrine disruption.

Immunotherapy and Immune Infiltration in Patients with Clear Cell Renal Cell Carcinoma: A Comprehensive Analysis

On a global scale, renal cell carcinoma (RCC) is the second most common form of cancer and the 10th leading cause of cancer-related deaths. There are about 70% of cases of RCC that are clear cell renal cell carcinomas (ccRCCs). This study explores possible targets for immune therapy in patients with RCC. In the recent years, immunotherapy has been applied to RCC patients. In order to identify genes that are closely associated with immune cells, a weighted gene coexpression network analysis (WGCNA) was conducted. A close association was found between genes involved in MEred and M0 macrophages, M1 macrophages, and M2 macrophages. A prognostic prediction model is subsequently developed by incorporating the OS and the expression level of key genes from the RCC cohort into a univariate COX regression analysis, a multivariate COX regression analysis, and a combined COX regression analysis. We finally discovered that 6 genes are closely associated with the prognosis of RCC patients, including SLC16A12, SLC2A9, IGF2BP2, EMX2, ANK3, and METTL7A. The survival analysis proved the prognostic prediction value of the model. The 1-year, 3-year, and 5-year AUC of ROC curves are 0.759, 0.723, and 0.733, respectively. For clinical ROC curves, the AUC score for risk score, stage, grade, and T stage is 0.759, 0.824, 0722, and 0.736, respectively. The nomogram was constructed for better prognosis prediction of RCC patients. In addition, GSVA and GO enrichment analysis was performed to explore the potential pathways that are closely associated with genes involved in the prognostic prediction model. Accordingly, our study demonstrates that immune cells play a crucial role in RCC infiltration. The development of a prognostic prediction model is a potential new prognostic biomarker and potential immunotherapy target for tumors.

Prenatal BPA exposure disrupts male reproductive functions by interfering with DNA methylation and GDNF expression in the testes of male offspring rats

BPA is a ubiquitous environmental endocrine-disrupting chemical, and maternal exposure to BPA is associated with impaired male reproductive functions; however, the mechanisms remain to be elucidated. Glial cell line-derived neurotrophic factor (GDNF) plays an important role in maintaining normal spermatogenesis and fertility. However, the effect of prenatal BPA exposure on GDNF expression and its mechanism in the testis has not been reported. In this study, pregnant Sprague-Dawley rats were respectively exposed to 0, 0.05, 0.5, 5, and 50 mg/kg/day BPA via oral gavage from gestational day (GD) 5 to GD 19, with 6 pregnant rats in each group. ELISA, histochemistry, real-time PCR, western blot, and methylation-specific PCR (MSP) were used to detect the sex hormone levels, testicular histopathology, mRNA and protein expression of DNA methyltransferases (DNMTs) and GDNF, and the promoter methylation of Gdnf in the testes of male offspring at postnatal day (PND) 21 and PND 56. Prenatal BPA exposure increased body weight; decreased sperm counts and serum levels of testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH); and induced testicular histological damage, which indicated the damage of male reproductive function. Prenatal BPA exposure also upregulated Dnmt1 in 5 mg/kg group and Dnmt3b in 0.5 mg/kg group, but down-regulated Dnmt1 in 50 mg/kg group at PND 21. At PND 56, Dnmt1 was significantly increased in 0.05 mg/kg group but decreased in 0.5, 5, and 50 mg/kg groups, Dnmt3a was decreased, and Dnmt3b was markedly increased in 0.05 and 0.5 mg/kg groups but decreased in 5 and 50 mg/kg groups. The mRNA and protein expression levels of Gdnf were decreased markedly in 0.5 and 50 mg/kg groups at PND 21. And the methylation level of Gdnf promoter was significantly increased in 0.5 mg/kg group, but decreased in 5 and 50 mg/kg groups at PND 21. In conclusion, our study indicates that prenatal BPA exposure disrupts male reproductive functions, interferes with the expression of DNMTs, and decreases Gdnf expression in the testes of male offspring. Gdnf expression may be regulated by DNA methylation; however, the detailed mechanism needs to be further investigated.

Hazard characterization of bisphenol A (BPA) based on rodent models - Multilevel meta-analysis and dose-response analysis for reproductive toxicity

Bisphenol A (BPA) is a widely used synthetic industrial compound frequently detected in food. Dietary exposure to BPA has been recognised as a potential health concern. However, there are uncertainties regarding BPA toxicity. The primary objective of this study was to summarise and analyse multiple toxicity endpoints of adverse reproductive effects caused by BPA exposure in rodent models. Therefore, a multilevel meta-analysis and subsequent dose-response analysis were conducted. Relevant articles published in English between 2012 and 2021 were collected from online databases, viz. Scopus, EmBase, Web of Science, and PubMed. In total, 41 studies were included for statistical analysis. All statistical analyses were performed using open-source RStudio packages. Summary effects indicated the statistical significance of BPA exposure on decreased sperm concentration (Hedges' g: -1.35) and motility (Hedges' g: -1.12) on average, while no significant effects were observed on the absolute and relative weight of male and female reproductive organs. The lowest mean toxicological reference dose values of 0.0011 mg (kg bw)^-1 day^-1 was proposed for BPA exposure on sperm concentration from the dose-response model. In conclusion, potential health risks from BPA exposure were shown with regards to reproductive toxicity, especially that sperm concentration and sperm motility require further attention.

The Identification of Immune-Related Biomarkers for Osteoarthritis Immunotherapy Based on Single-Cell RNA Sequencing Analysis

Osteoarthritis (OA) is a chronic musculoskeletal disease affecting approximately 500 million people worldwide. Globally, OA is one of the most common and leading causes of disability. Several genetic factors are involved in OA, including inherited genes, genetic susceptibility, and genetic predisposition. As the pathogenesis of OA is unknown, there are almost no effective treatments available to prevent the onset or progression of the disease. In recent years, many researchers focused on bioinformatics analysis to explore new biomarkers for the diagnosis, treatment, and prognosis of human diseases. In this work, we obtain the traditional RNA sequencing data of OA patients from the GEO database. By performing the differentially expressed analysis, we successfully obtain the genes that are closely associated with the OA. In addition, the Venn diagram was applied to evaluate the genes that are involved in OA and immune-related genes. The protein-protein interaction analysis was further conducted to explore the hub genes. The single-cell RNA sequencing analysis was used to evaluate the expression distribution of the MMP, VEGFA, SPI1, and IRF8 in synovial tissues of patients with osteoarthritis. Finally, the GSVA enrichment analysis discovered the potential pathways involved in OA patients. Our analysis provides a new direction for the exploration of the process of OA patients. In addition, VEGFA may be considered a promising biomarker in OA.

Comprehensive Analysis of the Association between Human Diseases and Water Pollutants

Drinking water is an important natural resource. For many people worldwide, especially in developing countries, access to safe drinking water is still a dream. An increasing number of human activities and industrialization have caused various physical, chemical, and biological pollutants to enter water bodies, affecting human health. Water pollutants contain a vast number of additives, such as perfluorinated chemicals, polybrominated diphenyl ethers, phthalate, nanomaterials, insecticides, microcystins, heavy metals, and pharmacologies. In this work, we aim to explore the potential relationship between water pollutants and human diseases. Here, we explored an integrative approach to identify genes, biological processes, molecular functions, and diseases linked to exposure to these water pollutants. These processes and functions affected by water pollutants are related to many diseases, including colonic neoplasms, breast neoplasms, hepatitis B, bladder cancer, and human cytomegalovirus infection. In addition, further analysis revealed the genes that play a key role in the human diseases induced by water pollutants. Therefore, conducting an integrative toxicogenomic analysis of water pollutants is more appropriate for evaluating the potential effects of water pollutants on human health.

Human health risk assessment of bisphenol A (BPA) through meat products

Meat and meat products are often consumed in our daily diet, providing essential nutrients. Contamination by chemical hazards, including bisphenol A (BPA) in meat products, is a concern and is continuously monitored. BPA is well-known for its endocrine-disrupting properties, which may cause potential toxicological effects on reproductive, nervous, and immune systems. Dietary consumption is the main route of BPA exposure, and meat products are a major contributor. BPA exposure from meat consumption is the focus of this review. This review found that BPA has been widely detected in canned and non-canned meat products. BPA in canned meat is assumed to be predominantly from migration from can coatings. Relatively low levels are observed in non-canned products, and the source of contamination in these products has yet to be definitively identified. A recent European Food Safety Authority (EFSA) draft opinion has proposed to lower the tolerable daily intake of BPA from 4 μg kg body weight (bw)^-1 day^-1 to 0.04 ng kg body weight (bw)^-1 day^-1, therefore potential health risks need to be addressed. This review has investigated potential contamination at the farm, industrial processes, and retail levels. Data gaps in the literature are also identified to improve future food safety in the meat industry. Also, a unified risk assessment strategy has been proposed. Further understanding of BPA migration in meat products is needed as a part of the exposure assessment to reduce potential risk, and more data on the dose-response relationship will help comprehend potential adverse health effects of BPA on humans. This research will inform the public, meat producers and processing industry, and policymakers on potential exposure to BPA and risk reduction measures, thus, ensuring food safety.

Systematic Review Methodologies and Endocrine Disrupting Chemicals: Improving Evaluations of the Plastic Monomer Bisphenol A

BACKGROUND

Endocrine disrupting chemicals (EDCs) are found in plastics, personal care products, household items, and other consumer goods. Risk assessments are intended to characterize a chemical's hazards, identify the doses at which adverse outcomes are observed, quantify exposure levels, and then compare these doses to determine the likelihood of risk in a given population. There are many problems with risk assessments for EDCs, allowing people to be exposed to levels that are later associated with serious health outcomes in epidemiology studies.

OBJECTIVE

In this review, we examine issues that affect the evaluation of EDCs in risk assessments (e.g., use of insensitive rodent strains and absence of disease-oriented outcomes in hazard assessments; inadequate exposure assessments). We then review one well-studied chemical, Bisphenol A (BPA; CAS #80-05-7) an EDC found in plastics, food packaging, and other consumer products. More than one hundred epidemiology studies suggest associations between BPA exposures and adverse health outcomes in environmentally exposed human populations.

FINDINGS

We present support for the use of systematic review methodologies in the evaluation of BPA and other EDCs. Systematic reviews would allow studies to be evaluated for their reliability and risk of bias. They would also allow all data to be used in risk assessments, which is a requirement for some regulatory agencies.

CONCLUSION

Systematic review methodologies can be used to improve evaluations of BPA and other EDCs. Their use could help to restore faith in risk assessments and ensure that all data are utilized in decision-making. Regulatory agencies are urged to conduct transparent, well-documented and proper systematic reviews for BPA and other EDCs.