Cyanobacteria blooms and non-alcoholic liver disease: evidence from a county level ecological study in the United States

Geospatial analysis of cyanobacterial exposure and liver cancer in the contiguous United States

BACKGROUND AND AIMS

Cyanobacteria are commonly found in water bodies and their production of hepatotoxins can contribute to liver damage. However, the population health effects of cyanobacteria exposure (CE) are unknown. Our objectives were to determine the effect of chronic exposure to cyanobacteria through proximity to water bodies with high cyanobacteria counts on the incidence and mortality of liver cancers, as well as to identify location-based risk factors.

APPROACH AND RESULTS

Across the contiguous United States, regions with high cyanobacteria counts in water bodies were identified using satellite remote sensing data. The data were geospatially mapped to county boundaries, and disease mortality and incidence rates were analyzed. Distinctive spatial clusters of CE and mortality related to liver diseases or cancer were identified. There was a highly significant spatial association between CE, liver disease, and liver cancer but not between CE and all cancers. Hot spots of CE and mortality were identified along the Gulf of Mexico, eastern Texas, Louisiana, and Florida, and cold spots across the Appalachians. The social vulnerability index was identified as a major location-based determinant by logistic regression, with counties in the fourth or fifth quintiles having the highest prevalence of hot spots of CE and mortality from liver cancer.

CONCLUSIONS

These findings emphasize the importance of environmental exposure to cyanobacteria as a location-based determinant of mortality from liver cancer. Public health initiatives addressing CE may be considered to reduce mortality, particularly in areas of high social vulnerability.

The mediating role of AKT/ERK/JNK signaling on the malignant phenotype of microcystin-LR in gastric adenocarcinoma cells

Microcystin-leucine arginine (MC-LR), a widely distributed and highly toxic environmental pollutant, plays crucial roles in cancer malignancy by activating characteristically toxic signaling pathways. Traditional animal-based toxicity evaluation methods have proven insufficient for identifying the specific role of these signaling pathways. Therefore, this study aimed to uncover the regulatory relationship between the toxic pathways and the progression of gastric cancer (GC). The findings provide novel avenues for conducting in vitro toxicity tests based on the investigated pathways. We found that MC-LR promoted the migration and invasion of SGC-7901 cells while simultaneously inhibiting their apoptosis in a dose-dependent manner. This observed cytotoxicity was primarily mediated through the AKT, JNK, and ERK signaling pathways. By using a mediation analysis model, we determined that AKT and ERK exhibited competitive effects in MC-LR-treated GC malignancy, while AKT and JNK acted independently from one another. This study establishes an in vitro toxicity test model of MC-LR based on toxicity-related pathways and underscores the pivotal roles of AKT, ERK, and JNK signaling in MC-LR toxicity. The findings offer a novel, fundamental framework for conducting chemical toxicity risk assessment.

Remote estimation of phycocyanin concentration in inland waters based on optical classification

In recent years, under the dual pressure of climate change and human activities, the cyanobacteria blooms in inland waters have become a threat to global aquatic ecosystems and the environment. Phycocyanin (PC), a diagnostic pigment of cyanobacteria, plays an essential role in the detection and early warning of cyanobacterial blooms. In this context, accurate estimation of PC concentration in turbid waters by remote sensing is challenging due to optical complexity and weak optical signal. In this study, we collected a comprehensive dataset of 640 pairs of in situ measured pigment concentration and the Ocean and Land Color Instrument (OLCI) reflectance from 25 lakes and reservoirs in China during 2020-2022. We then developed a framework consisting of the water optical classification algorithm and three candidate algorithms: baseline height, band ratio, and three-band algorithm. The optical classification method used remote sensing reflectance (Rrs) baseline height in three bands: Rrs(560), Rrs(647) and Rrs(709) to classify the samples into five types, each with a specific spectral shape and water quality character. The improvement of PC estimation accuracy for optically classified waters was shown by comparison with unclassified waters with RMSE = 72.6 μg L-1, MAPE = 80.4 %, especially for the samples with low PC concentration. The results show that the band ratio algorithm has a strong universality, which is suitable for medium turbid and clean water. In addition, the three-band algorithm is only suitable for medium turbid water, and the line height algorithm is only suitable for high PC content water. Furthermore, the five distinguished types with significant differences in the value of the PC/Chla ratio well indicated the risk rank assessment of cyanobacteria. In conclusion, the proposed framework in this paper solved the problem of PC estimation accuracy problem in optically complex waters and provided a new strategy for water quality inversion in inland waters.

Beyond cyanotoxins: increased Legionella, antibiotic resistance genes in western Lake Erie water and disinfection-byproducts in their finished water

Background

Western Lake Erie is suffering from harmful cyanobacterial blooms, primarily toxic Microcystis spp., affecting the ecosystem, water safety, and the regional economy. Continued bloom occurrence has raised concerns about public health implications. However, there has been no investigation regarding the potential increase of Legionella and antibiotic resistance genes in source water, and disinfection byproducts in municipal treated drinking water caused by these bloom events.

Methods

Over 2 years, source water (total n = 118) and finished water (total n = 118) samples were collected from drinking water plants situated in western Lake Erie (bloom site) and central Lake Erie (control site). Bloom-related parameters were determined, such as microcystin (MC), toxic Microcystis, total organic carbon, N, and P. Disinfection byproducts (DBPs) [total trihalomethanes (THMs) and haloacetic acids (HAAs)] were assessed in finished water. Genetic markers for Legionella, antibiotic resistance genes, and mobile genetic elements were quantified in source and finished waters.

Results

Significantly higher levels of MC-producing Microcystis were observed in the western Lake Erie site compared to the control site. Analysis of DBPs revealed significantly elevated THMs concentrations at the bloom site, while HAAs concentrations remained similar between the two sites. Legionella spp. levels were significantly higher in the bloom site, showing a significant relationship with total cyanobacteria. Abundance of ARGs (tetQ and sul1) and mobile genetic elements (MGEs) were also significantly higher at the bloom site.

Discussion

Although overall abundance decreased in finished water, relative abundance of ARGs and MGE among total bacteria increased after treatment, particularly at the bloom site. The findings underscore the need for ongoing efforts to mitigate bloom frequency and intensity in the lake. Moreover, optimizing water treatment processes during bloom episodes is crucial to maintain water quality. The associations observed between bloom conditions, ARGs, and Legionella, necessitate future investigations into the potential enhancement of antibiotic-resistant bacteria and Legionella spp. due to blooms, both in lake environments and drinking water distribution systems.

Cyanophage-cyanobacterial interactions for sustainable aquatic environment

Cyanobacteria are a type of bloom-forming phytoplankton that cause environmental problems in aquatic ecosystems worldwide. Cyanobacterial harmful algal blooms (cyanoHAB) often produce cyanotoxins that affect public health by contaminating surface waters and drinking water reservoirs. Conventional drinking water treatment plants are ineffective in treating cyanotoxins, even though some treatment methods are available. Therefore, innovative and advanced treatment methods are required to control cyanoHABs and their cyanotoxins. The goal of this review paper is to provide insight into the use of cyanophages as an effective form of biological control method for the removal of cyanoHABs in aquatic systems. Moreover, the review contains information on cyanobacterial blooms, cyanophage-cyanobacteria interactions, including infection mechanisms, as well as examples of different types of cyanobacteria and cyanophages. Moreover, the real-life application of cyanophages in marine and freshwater environments and the mode of action of cyanophages were compiled.

Cyanotoxins Increase Cytotoxicity and Promote Nonalcoholic Fatty Liver Disease Progression by Enhancing Cell Steatosis

Freshwater prokaryotic cyanobacteria within harmful algal blooms produce cyanotoxins which are considered major pollutants in the aquatic system. Direct exposure to cyanotoxins through inhalation, skin contact, or ingestion of contaminated drinking water can target the liver and may cause hepatotoxicity. In the current study, we investigated the effect of low concentrations of cyanotoxins on cytotoxicity, inflammation, modulation of unfolded protein response (UPR), steatosis, and fibrosis signaling in human hepatocytes and liver cell models. Exposure to low concentrations of microcystin-LR (MC-LR), microcystin-RR (MC-RR), nodularin (NOD), and cylindrospermopsin (CYN) in human bipotent progenitor cell line HepaRG and hepatocellular carcinoma (HCC) cell lines HepG2 and SK-Hep1 resulted in increased cell toxicity. MC-LR, NOD, and CYN differentially regulated inflammatory signaling, activated UPR signaling and lipogenic gene expression, and induced cellular steatosis and fibrotic signaling in HCC cells. MC-LR, NOD, and CYN also regulated AKT/mTOR signaling and inhibited autophagy. Chronic exposure to MC-LR, NOD, and CYN upregulated the expression of lipogenic and fibrosis biomarkers. Moreover, RNA sequencing (RNA seq) data suggested that exposure of human hepatocytes, HepaRG, and HCC HepG2 cells to MC-LR and CYN modulated expression levels of several genes that regulate non-alcoholic fatty liver disease (NAFLD). Our data suggest that low concentrations of cyanotoxins can cause hepatotoxicity and cell steatosis and promote NAFLD progression.

Downregulation of LncRNA GCLC-1 Promotes Microcystin-LR-Induced Malignant Transformation of Human Liver Cells by Regulating GCLC Expression

Microcystin-LR (MCLR) is an aquatic toxin, which could lead to the development of hepatocellular carcinoma (HCC). Long non-coding RNAs (lncRNAs) are considered important regulatory elements in the occurrence and development of cancer. However, the roles and mechanisms of lncRNAs during the process of HCC, induced by MCLR, remain elusive. Here, we identified a novel lncRNA, namely lnc-GCLC-1 (lncGCLC), which is in close proximity to the chromosome location of glutamate-cysteine ligase catalytic subunit (GCLC). We then investigated the role of lncGCLC in MCLR-induced malignant transformation of WRL68, a human hepatic cell line. During MCLR-induced cell transformation, the expression of lncGCLC and GCLC decreased continuously, accompanied with a consistently high expression of miR-122-5p. Knockdown of lncGCLC promoted cell proliferation, migration and invasion, but reduced cell apoptosis. A xenograft nude mouse model demonstrated that knockdown of lncGCLC promoted tumor growth. Furthermore, knockdown of lncGCLC significantly upregulated miR-122-5p expression, suppressed GCLC expression and GSH levels, and enhanced oxidative DNA damages. More importantly, the expression of lncGCLC in human HCC tissues was significantly downregulated in the high-microcystin exposure group, and positively associated with GCLC level in HCC tissues. Together, these findings suggest that lncGCLC plays an anti-oncogenic role in MCLR-induced malignant transformation by regulating GCLC expression.

Comprehensive proteomic and phosphoproteomic reveal that Microcystin-LR contributed to the malignant progression of gastric cancer by estrogenic potency

The widespread cyanotoxins in drinking water pose a threat to public health induced by Microcystins (MCs). MC-LR, a predominant toxic form of MCs, has been found to play critical roles in cancer progression. The role of MC-LR in hepatocarcinogenesis has attracted extensive attention. However, as a critical digestive organ, the precise mechanism of MC-LR-induced gastric cancer is still unclear. We found that 100 nM MC-LR promoted the proliferation, migration, invasion, and anti-apoptosis of SGC-7901 cells. Quantitative proteome and phosphoproteome analysis identified differential expression patterns and aberrant pathways of SGC-7901 cells exposed to MC-LR. The results indicated that 48,109 unique peptides from 6320 proteins and 1375 phosphoproteins with 3473 phosphorylation sites were detected after 24 h treatment of MC-LR. Proteome and phosphoproteome conjoint analysis indicated estrogen signaling pathway might play an essential step in MC-LR-treated molecular events. The mechanism underlying these changes may involve MC-LR excessively activating the estrogen signaling pathway by reducing Hsp90 phosphorylation, which results in nucleus translocation of activated ERα and Krt16 overexpression in gastric cells. In general, our results indicate multiple crucial signals triggered by MC-LR, among which MC-LR may promote the development of gastric cancer by exerting estrogenic potency.

Diagnostic and prognostic value of STAP1 and AHNAK methylation in peripheral blood immune cells for HBV-related hepatopathy

Introduction

Although we had identified that the methylation of AHNAK was a good diagnostic marker for hepatopathy, here we speculate that there was also another marker, STAP1, whose methylation also involved in the detection of hepatopathy.

Methods

We investigated the methylation levels of the AHNAK and STAP1 in peripheral blood mononuclear cells of chronic hepatitis B (CHB) patients, compensatory liver cirrhosis (CLC) patients, decompensated liver cirrhosis (DCLC) patients, hepatocellular carcinoma (HCC) patients and healthy controls by methylation-specific PCR. We also evaluated the differences and changes of methylation and expression of AHNAK and STAP1 at different stages of liver disease using the TCGA and GEO public datasets.

Results

Methylation level of STAP1 in PBMC was positively correlated with the course of liver cancer. The combination of AHNAK and STAP1 methylation was able to predict differrent HBV related hepatopathy. The GEO datasets also supported that the methylation of AHNAK and STAP1 was associated with different types of hepatopathy. The TCGA data showed that the levels of methylation and expression of STAP1 were down-regulated in HCC. We also found the STAP1 methylation level in PBMC and T cells was associated with age, gender, alcohol drinking and anti-HBe. Hyper-methylation of STAP1 was correlated with the poor prognosis of patients but its expression had no association.

Conclusion

We concluded that combination of AHNAK and STAP1 methylation in peripheral blood immune cells can be used as a diagnostic marker for HBV related hepatopathy and STAP1 methylation may be a potential prognostic marker for HBV related HCC. Our clinical study registration number was ChiCTR2000039860.

A new identity of microcystins: Environmental endocrine disruptors? An evidence-based review

Microcystins (MCs) are widely distributed cyanobacterial toxins in eutrophic waters. At present, the endocrine-disrupting effects of MCs have been extensively studied, but whether MCs can be classified as environmental endocrine disruptors (EDCs) is still unclear. This review is aimed to evaluate the rationality for MCs as to be classified as EDCs based on the available evidence. It has been identified that MCs meet eight of ten key characteristics of chemicals that can be classified as EDCs. MCs interfere with the six processes, including synthesis, release, circulation, metabolism, binding and action of natural hormones in the body. Also, they are fit two other characteristics of EDC: altering the fate of producing/responding cells and epigenetic modification. Further evidence indicates that the endocrine-disrupting effect of MCs may be an important cause of adverse health outcomes such as metabolic disorders, reproductive disorders and effects on the growth and development of offspring. Generally, MCs have endocrine-disrupting properties, suggesting that it is reasonable for them to be considered EDCs. This is of great importance in understanding and evaluating the harm done by MCs on humans.

Relationship between freshwater harmful algal blooms and neurodegenerative disease incidence rates in South Korea

BACKGROUND

Due to anthropogenic activities and global warming, the severity and distribution of harmful algal blooms (HABs) have been increasing steadily worldwide, including in South Korea (S. Korea). Previous studies reported that exposure to HABs could increase the risk of HAB-related diseases. However, very few studies examined the linkage between HABs and disease occurrence, particularly in S. Korea. The objective of this study was to evaluate the potential impact of HABs on neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, and motor neuron disease, at a population level.

METHODS

Thirteen-year data (2005-2017) for chlorophyll-a (chl-a) concentrations as a bloom-related parameter, annual numbers of NDs, and population information were collected. First, the entire area of S. Korea was divided into a grid of 1 km, and the population number in each 1-km grid was collected using the Statistical Geographic Information Service Plus system. Cross-sectional time series data were analyzed with two statistical models, a generalized linear mixed model and a generalized linear model.

RESULTS

The results show a general trend of increasing chl-a concentration and NDs year by year. We observed positive correlations between HAB intensity and the incidence rate of NDs. Particularly, HABs seem to have the most long-term carry-over effect on Parkinson's disease. Another key finding was that a 5-km radius from the HAB location was the boundary that showed the most significant associations with three NDs.

CONCLUSIONS

This study provides statistical evidence that supports the potential risk of NDs from the exposure to HAB. Thus, it is recommended to monitor a broad spectrum of cyanotoxins, including neurotoxins, in bloom-affected regions in S. Korea and epidemiological studies in the future.

Promotion effect on liver tumor progression of microcystin-LR at environmentally relevant levels in female krasV12 transgenic zebrafish

Microcystin-LR (MC-LR) is a kind of natural toxin which exists widely in aquatic environments and has been reported to be hepatotoxic and carcinogenic. At present, the promoting mechanism of MC-LR on hepatocellular carcinoma (HCC) remains largely unexplored. In this study, the hepatocellular promoting effect of MC-LR was described in Kras^V12 transgenic zebrafish, a doxycycline (DOX) inducible HCC model. Our results showed that MC-LR could aggravate the progression of HCC at an environmentally relevant concentration (3 μg/L), which was accompanied by the decreased activity and down-regulated transcription level of serine/threonine phosphatase 2A (PP2A). Using TMT labeling quantitative phosphoproteomics, we found that the 1049 phosphopeptides were significantly changed (508 up-regulated and 541 down-regulated) in liver from combined exposure to DOX and 3 μg/L MC-LR group compared to the DOX group. Enriched pathways by KEGG analysis suggested that differentially phosphorylated proteins were mainly related to Wnt signaling pathway. Furthermore, the mRNA expression and protein abundance of β-Catenin in Wnt signaling pathway were significantly up-regulated following exposure to MC-LR. In short, our results suggested that MC-LR significantly inhibited the activity of PP2A, which in turn activated Wnt signaling, eventually resulting in progression of liver tumor in transgenic zebrafish.

Environmental Exposure to Cyanobacteria Hepatotoxins in a Pacific Island Community: A Cross-Sectional Assessment

(1) Background: Cyanobacteria produce a wide range of secondary metabolites, including tumor-promoting hepatotoxins. We recently reported evidence of an independent association between oral cyanobacteria and hepatocellular carcinoma in a U.S. population. We sought to characterize the nature, sources, and health correlates of cyanotoxin exposure in the U.S. Pacific Island territory of Guam, which has a high incidence of liver cancer. (2) Methods: Seventy-four adult males and females were enrolled in a cross-sectional study to quantify cyanotoxins in saliva, urine, and blood and their correlation with health behaviors, medical history, and environmental exposures. Plant samples were collected from locations throughout the island. Microcystin/nodularin (MC/NOD), cylindrospermopsin (CYN), and anabaenopeptin (AB) were measured in biospecimens and in plant extracts by ELISA. (3) Results: Overall, among study participants MC/NOD were detected in 53.9% of saliva, 7.5% of urine, and 100% of serum.; CYN in 40.0% of saliva, 100.0% of urine, and 70.4% of serum; AB in 30.8% of saliva, 85% of urine, and 92.6% of serum. Salivary MC/NOD levels were significantly higher in individuals using municipal tap water as their primary source of drinking water; both salivary and urinary MC/NOD levels were higher in those not using store-bought/commercial water. Urine MC/NOD levels were highest among individuals consuming fruits and vegetables exclusively from local sources. Urine MC/NOD levels were elevated in individuals with hypertension and hyperlipidemia and salivary MC/NOD in those with recent alcohol consumption. Cyanotoxins were prevalent in plant samples including MC/NOD (46.6%), CYN (35.1%), and AB (51.7%). (4) Conclusions: Our study provides evidence that exposure to cyanobacterial hepatotoxins, including tumor promoters, may be prevalent in Guam and may originate from environmental sources. Population-based epidemiologic studies are needed to investigate the role of cyanotoxins in liver cancer development.

Ecological River Health Assessment Using Multi-Metric Models in an Asian Temperate Region with Land Use/Land Cover as the Primary Factor Regulating Nutrients, Organic Matter, and Fish Composition

This study was performed to determine the ecological health of a temperate river over nine years (2011−2019); it also analyzed the trophic structure and linkage of nutrients (nitrogen [N] and phosphorus [P]), sestonic chlorophyll-a (CHL-a), and the top trophic fish in the Asian monsoon region. Water chemistry, trophic indicators, and tolerance guilds were primarily influenced by land use and land cover (LULC); the magnitude of variation was also related to geographic elevation, artificial physical barriers (weirs), and point sources. Levels of nutrients, organic matter, and CHL-a largely influenced by the intensity of the monsoon seasonality for a particular LULC and stream order. Mann−Kendall tests based on a long-term annual dataset showed that annual organic matter and CHL-a increased over time because of longer hydraulic residence time after weir construction. The results of empirical nutrient models suggested that P was the key determinant for algal growth (CHL-a); the strong P-limitation was supported by N:P ratios > 17 in ambient waters. Linear regression models and canonical correspondence analysis (CCA) were used to determine the influences of LULC and water quality on the trophic/tolerance linkages, fish community compositions and structures, and river health. Tolerant species had a positive functional relationship with nutrient enrichment through total phosphorus (TP) (R2 = 0.55, p < 0.05) and total nitrogen (TN) (R2 = 0.57, p < 0.05), organic pollution in terms of biological oxygen demand (BOD) (R2 = 0.41, p < 0.05) and chemical oxygen demand (COD) (R2 = 0.49, p < 0.05), and algal growth (R2 = 0.47, p < 0.05); sensitive species exhibited the opposite pattern. The degradation of river health, based on the multi-metric index of biotic integrity (IBI) model, was evident in the downriver region (“fair−poor” condition) and was supported by the quantitative fish community index (QFCI) model. The outcomes suggested that the degradation and variation of ecological river health, trophic linkages of water chemistry (N, P)-algal biomass-fish, were largely controlled by the land use pattern and construction of physical barriers in relation to the Asian monsoon.

Impact of Cyanotoxin Ingestion on Liver Cancer Development Using an At-Risk Two-Staged Model of Mouse Hepatocarcinogenesis

Exposure to cyanobacterial hepatotoxins has been linked to the promotion and increased incidence of liver cancer in pre-clinical and epidemiologic studies. The family of hepatotoxins, microcystins (MCs), are produced by over 40 cyanobacterial species found in harmful algal blooms (HABs) worldwide, with MC-LR being the most common and potent MC congener. In the current study, we hypothesized that the low-dose chronic ingestion of Microcystis cyanotoxins via drinking water would promote liver carcinogenesis in pre-initiated mice. Four groups of C3H/HeJ mice received one intraperitoneal (i.p.) injection of diethylnitrosamine (DEN) at 4 weeks of age. Three weeks later, the mice were administered ad libitum drinking water containing one of the following: (1) reverse osmosis, deionized water; (2) water containing 500 mg/L phenobarbital (PB500); (3) water with purified MC-LR (10 µg/L) added; or (4) water containing lysed Microcystis aeruginosa (lysate; 10 µg/L total MCs). The exposure concentrations were based on environmentally relevant concentrations and previously established Ohio EPA recreational water MC guidelines. Throughout the 30-week exposure, mouse weights, food consumption, and water consumption were not significantly impacted by toxin ingestion. We found no significant differences in the number of gross and histopathologic liver lesion counts across the treatment groups, but we did note that the PB500 group developed lesion densities too numerous to count. Additionally, the proportion of lesions classified as hepatocellular carcinomas in the MC-LR group (44.5%; p < 0.05) and lysate group (55%; p < 0.01) was significantly higher compared to the control group (14.9%). Over the course of the study, the mice ingesting the lysate also had a significantly lower survival probability (64.4%; p < 0.001) compared to water (96.8%), PB500 (95.0%), and MC-LR (95.7%) exposures. Using cyanotoxin levels at common recreational water concentration levels, we demonstrate the cancer-promoting effects of a single cyanotoxin MC congener (MC-LR). Furthermore, we show enhanced hepatocarcinogenesis and significant mortality associated with combinatorial exposure to the multiple MCs and bioactive compounds present in lysed cyanobacterial cells—a scenario representative of the ingestion exposure route, such as HAB-contaminated water and food.

As We Drink and Breathe: Adverse Health Effects of Microcystins and Other Harmful Algal Bloom Toxins in the Liver, Gut, Lungs and Beyond

Freshwater harmful algal blooms (HABs) are increasing in number and severity worldwide. These HABs are chiefly composed of one or more species of cyanobacteria, also known as blue-green algae, such as Microcystis and Anabaena. Numerous HAB cyanobacterial species produce toxins (e.g., microcystin and anatoxin—collectively referred to as HAB toxins) that disrupt ecosystems, impact water and air quality, and deter recreation because they are harmful to both human and animal health. Exposure to these toxins can occur through ingestion, inhalation, or skin contact. Acute health effects of HAB toxins have been well documented and include symptoms such as nausea, vomiting, abdominal pain and diarrhea, headache, fever, and skin rashes. While these adverse effects typically increase with amount, duration, and frequency of exposure, susceptibility to HAB toxins may also be increased by the presence of comorbidities. The emerging science on potential long-term or chronic effects of HAB toxins with a particular emphasis on microcystins, especially in vulnerable populations such as those with pre-existing liver or gastrointestinal disease, is summarized herein. This review suggests additional research is needed to define at-risk populations who may be helped by preventative measures. Furthermore, studies are required to develop a mechanistic understanding of chronic, low-dose exposure to HAB toxins so that appropriate preventative, diagnostic, and therapeutic strategies can be created in a targeted fashion.

Alleviation of microcystin-LR-induced hepatic lipidosis and apoptosis in zebrafish by use of rice straw-derived biochar

Microcystin-LR (MC-LR), mainly released by Microcystis aeruginosa, is posing a tremendous risk to aquatic animals and human health. Meanwhile, biochar (BC) is gradually be used as a sustainable adsorbent to immobilize and remove water pollutants. In our study, we for the first time conducted a full-scale investigation on lipid metabolism and its regulation mechanism of female zebrafish (Danio rerio) exposed to 0, 10 μg/L MC-LR, 100 μg/L BC, and 10 μg/L MC-LR+ 100 μg/L BC. The results indicated that sub-chronic MC-LR exposure induced hepatic lipidosis and apoptosis, including the formation of lipid droplets, significantly elevation of hepatic triglyceride (TG) level as well as significant upregulated expression of lipogenesis-related genes (foxo1a, elovl5, pparγ) and pro-apoptotic genes (bax, casp3). Nevertheless, no significant alteration was observed in the single BC group and the combined exposure group, which indicated that BC may solely functioned as an absorbent agent to lower MC-LR bioaccumulation in zebrafish liver and alleviate MC-LR-induced hepatotoxicity. Our findings revealed that the utilization of rice straw-derived BC can adsorb and immobile MC-LR in the water, subsequently alleviated the MC-LR-induced hepatic lipidosis and apoptosis in female zebrafish. On the basis of fish health, it is urgent to explore the feasibility of using environmentally friendly materials like BC to adsorb pollutants in water.

Oral Cyanobacteria and Hepatocellular Carcinoma

BACKGROUND

Gut microbial alterations have been linked to chronic liver disease and hepatocellular carcinoma (HCC). The role of the oral microbiome in liver cancer development has not been widely investigated.

METHODS

Bacterial 16S rRNA sequences were evaluated in oral samples from 90 HCC cases and 90 controls who were a part of a larger U.S. case-control study of HCC among patients diagnosed from 2011 to 2016.

RESULTS

The oral microbiome of HCC cases showed significantly reduced alpha diversity compared with controls (Shannon P = 0.002; Simpson P = 0.049), and beta diversity significantly differed (weighted Unifrac P = 0.004). The relative abundance of 30 taxa significantly varied including Cyanobacteria, which was enriched in cases compared with controls (P = 0.018). Cyanobacteria was positively associated with HCC [OR, 8.71; 95% confidence interval (CI), 1.22-62.00; P = 0.031] after adjustment for age, race, birthplace, education, smoking, alcohol, obesity, type 2 diabetes, Hepatitis C virus (HCV), Hepatitis B virus (HBV), fatty liver disease, aspirin use, other NSAID use, laboratory batch, and other significant taxa. When stratified by HCC risk factors, significant associations of Cyanobacteria with HCC were exclusively observed among individuals with negative histories of established risk factors as well as females and college graduates. Cyanobacterial genes positively associated with HCC were specific to taxa producing microcystin, the hepatotoxic tumor promotor, and other genes known to be upregulated with microcystin exposure.

CONCLUSIONS

Our study provides novel evidence that oral Cyanobacteria may be an independent risk factor for HCC.

IMPACT

These findings support future studies to further examine the causal relationship between oral Cyanobacteria and HCC risk.

Remote Sensing Detection of Algal Blooms in a Lake Impacted by Petroleum Hydrocarbons

The purpose of this study was to combine all available information on the state of Lake Pertusillo (Basilicata, Italy), both in the field and published, which included Sentinel-2A satellite data, to understand algal blooms in a lacustrine environment impacted by petroleum hydrocarbons. Sentinel-2A data was retrospectively used to monitor the state of the lake, which is located near the largest land-based oil extraction plant in Europe, with particular attention to chlorophyll a during algal blooms and petroleum hydrocarbons. In winter 2017, a massive dinoflagellate bloom (10.4 × 106 cell/L) of Peridinium umbonatum and a simultaneous presence of hydrocarbons were observed at the lake surface. Furthermore, a recent study using metagenomic analyses carried out three months later identified a hydrocarbonoclastic microbial community specialized in the degradation aromatic and nitroaromatic hydrocarbons. In this study, Sentinel-2A imagery was able to detect the presence of chlorophyll a in the waters, while successfully distinguishing the signal from that of hydrocarbons. Remotely sensed results confirmed surface reference measurements of lacustrine phytoplankton, chlorophyll a, and the presence of hydrocarbons during algal blooms, thereby explaining the presence of the hydrocarbonoclastic microbial community found in the lake three months after the oil spill event. The combination of emerging methodologies such as satellite systems and metagenomics represent an important support methodology for describing complex contaminations in diverse ecosystems.

Advances in the toxicology research of microcystins based on Omics approaches

Microcystins (MCs) are the most widely distributed cyanotoxins, which can be ingested by animals and human body in multiple ways, resulting in a threat to human health and the biodiversity of wildlife. Therefore, the study on toxic effects and mechanisms of MCs is one of the focuses of attention. Recently, the Omics techniques, i.e. genomics, transcriptomics, proteomics and metabolomics, have significantly contributed to the comprehensive understanding and revealing of the molecular mechanisms about the toxicity of MCs. This paper mainly reviews current literature using the Omics approaches to explore the toxicity mechanism of MCs in liver, gonad, spleen, brain, intestine and lung of multiple species. It was found that MCs can exert strong toxic effects on various metabolic activities and cell signal transduction in cell cycle, apoptosis, destruction of cell cytoskeleton and redox disorder, at protein, transcription and metabolism level. Meanwhile, it was also revealed that the alteration of non-coding RNAs (miRNA, circRNA and lncRNA, etc.) and gut microbiota plays an essential regulatory role in the toxic effects of MCs, especially in hepatotoxicity and reproductive toxicity. In addition, we summarized current research gaps and pointed out the future directions for research. The detailed information in this paper shows that the application and development of Omics techniques have significantly promoted the research on MCs toxicity, and it is also a valuable resource for exploring the toxic mechanism of MCs.

Microcystin Toxicokinetics, Molecular Toxicology, and Pathophysiology in Preclinical Rodent Models and Humans

Microcystins are ubiquitous toxins produced by photoautotrophic cyanobacteria. Human exposures to microcystins occur through the consumption of contaminated drinking water, fish and shellfish, vegetables, and algal dietary supplements and through recreational activities. Microcystin-leucine-arginine (MCLR) is the prototypical microcystin because it is reported to be the most common and toxic variant and is the only microcystin with an established tolerable daily intake of 0.04 µg/kg. Microcystin toxicokinetics is characterized by low intestinal absorption, rapid and specific distribution to the liver, moderate metabolism to glutathione and cysteinyl conjugates, and low urinary and fecal excretion. Molecular toxicology involves covalent binding to and inhibition of protein phosphatases, oxidative stress, cell death (autophagy, apoptosis, necrosis), and cytoskeleton disruption. These molecular and cellular effects are interconnected and are commonly observed together. The main target organs for microcystin toxicity are the intestine, liver, and kidney. Preclinical data indicate microcystins may also have nervous, pulmonary, cardiac, and reproductive system toxicities. Recent evidence suggests that exposure to other hepatotoxic insults could potentiate microcystin toxicity and increase the risk for chronic diseases. This review summarizes the current knowledge for microcystin toxicokinetics, molecular toxicology, and pathophysiology in preclinical rodent models and humans. More research is needed to better understand human toxicokinetics and how multifactorial exposures contribute to disease pathogenesis and progression.

Variability in microcystin quotas during a Microcystis bloom in a eutrophic lake

Microcystis is a bloom-forming genus of cyanobacteria with some genotypes that produce highly toxic microcystin hepatotoxins. In waterbodies where biological and physical factors are relatively homogenous, toxin quotas (the average amount of toxin per cell), at a single point in time, are expected to be relatively constant. In this study we challenged this assumption by investigating the spatial distribution of microcystin quotas at a single point in time on two separate occasions in a lake with a major Microcystis bloom. Microcystis cell concentrations varied widely across the lake on both sampling occasions (730- and 137-fold) together with microcystin quotas (148- and 362-fold). Cell concentrations and microcystin quotas were strongly positively correlated (R2 = 0.89, P < 0.001, n = 28; R2 = 0.67, P < 0.001, n = 25). Analysis of Microcystis strains using high-throughput sequencing of the 16S-23S rRNA intergenic spacer region showed no relationship between microcystin quota and the relative abundance of specific sequences. Collectively, the results of this study indicate an association between microcystin production and cell density that magnifies the potential for bloom toxicity at elevated cell concentrations.

Lactobacillus acidophilus LA14 Alleviates Liver Injury

Although the probiotic Lactobacillus acidophilus LA14 is used worldwide, its effect on liver diseases remains unelucidated. Here, 32 rats were divided into four groups, gavaged with L. acidophilus LA14 (3 × 10⁹ CFU) or phosphate-buffered saline for 7 days, and then intraperitoneally injected with d-galactosamine or saline. After 24 h, blood, liver, ileum, and feces samples were collected for liver injury, inflammation, intestinal barrier, gut microbiota, metabolome, and transcriptome analyses. Pretreatment with L. acidophilus LA14 alleviated the d-galactosamine-induced elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bile acids; mitigated the histological injury to the liver and gut; and suppressed the inflammatory cytokines macrophage inflammatory protein 1α (MIP-1α), MIP-3α, and MCP-1. L. acidophilus LA14 also ameliorated the d-galactosamine-induced dysbiosis of the gut microbiota and metabolism, such as the enrichment of Bacteroides sp. strain dnLKV3 and the depletion of Streptococcus, butanoic acid, and N-acetyl-d-glucosamine. The underlying mechanism of L. acidophilus LA14 included prevention of not only the d-galactosamine-induced upregulation of infection- and tumor-related pathways but also the d-galactosamine-induced downregulation of antioxidation-related pathways during this process, as reflected by the liver transcriptome and proteome analyses. Furthermore, the administration of L. acidophilus LA14 to healthy rats did not alter the tested liver indicators but significantly enriched the beneficial Lactobacillus and Bifidobacterium species, promoted metabolism and regulated pathways to improve immunity. The ability of L. acidophilus LA14 to alleviate liver injury was further confirmed with an acetaminophen-induced mouse model. These results might provide a reference for future studies on the application of L. acidophilus LA14 for the prevention of liver injury.

IMPORTANCE The probiotic Lactobacillus acidophilus LA14 is widely used, but its effect on liver diseases has not been elucidated. We explored the protective effect of L. acidophilus LA14 on the liver using rats with d-galactosamine-induced liver injury. Pretreatment with L. acidophilus LA14 alleviated the d-galactosamine-induced elevation of serum ALT, AST, ALP, and bile acids, mitigated the histological injury to the liver and gut, and suppressed the inflammatory cytokines MIP-1α, MIP-3α, and MCP-1. These effects were correlated with the modulations of the gut microbiome, metabolome, and hepatic gene expression induced by L. acidophilus LA14. Moreover, the ability of L. acidophilus LA14 to alleviate liver injury was further confirmed with an acetaminophen-induced mouse model. These results might provide a reference for future studies on the application of L. acidophilus LA14 for the prevention of liver injury.

Colonization of toxic cyanobacteria on the surface and inside of leafy green: A hidden source of cyanotoxin production and exposure

Cyanobacteria are a threat to the safety of water sources for drinking, recreation, and food production, because some cyanobacteria, such as Microcystis, produce cyanotoxins. However, the colonization of plants by Microcystis and the fate of their toxin, microcystins (MCs), in agricultural environments have not been thoroughly studied. This study examined the colonization of lettuce, as a representative of leafy greens, by Microcystis and its potential impact on food safety and crop health. The surfaces of lettuce leaves were exposed to environmentally relevant concentrations of M. aeruginosa (104, 106, and 108mcyE gene copies/mL) by mimicking contamination scenarios during cultivation, such as spraying irrigation with contaminated water or deposits of airborne Microcystis. Scanning electron microscope (SEM) and droplet digital PCR were used. The results showed that M. aeruginosa colonized the surface of leaves and MCs accumulated in the edible part of the lettuce (>20 μg/kg of lettuce). Crop productivity (length, weight, and number of leaves) was negatively affected. The SEM images provide evidence that M. aeruginosa deposited on the lettuce surface can be internalized via natural opening sites of the leaves and then proliferate within the plants. Our findings imply that toxic cyanobacteria contamination in agricultural environments can be a significant cyanotoxin exposure pathway.

Oral exposure to environmental cyanobacteria toxins: Implications for cancer risk

BACKGROUND

Areca nut/betel quid (AN/BQ) chewing, a prevalent practice in parts of the Pacific and Asia, is an independent cause of cancers of the oral cavity and esophagus and may be linked to liver cancer. The mechanisms of AN/BQ-associated carcinogenesis are unclear. In a Guam population, we previously demonstrated that AN/BQ chewing alters the oral bacterial microbiome including in chewers with oral premalignant lesions. Enrichment of specific taxa, including Cyanobacteria, was observed.

OBJECTIVES

We undertook an investigation to evaluate Areca catechu and/or Piper betle plants as potential sources of Cyanobacteria and cyanotoxins in AN/BQ chewers in Guam.

METHODS

We evaluated bacterial 16S rRNA with Illumina MiSeq in 122 oral samples and 30 Areca catechu nut and Piper betle leaf samples. Cyanobacteria sequences were interrogated using the NCBI database to identify candidate species and their reference sequences were evaluated for secondary metabolite toxins using AntiSMASH 5.0. Selected toxins were measured by ELISA in extracts from 30 plant samples and in a subset of 25 saliva samples.

RESULTS

Cyanobacteria was the predominant taxa in Areca catechu and Piper betle plants, comprising 75% of sequences. Cyanobacteria was detected at low levels in oral samples but 90-fold higher in current AN/BQ chewers compared to former/never chewers (p = 0.001). Microcystin/nodularin was detected in saliva (15 of 25 samples) and Piper betle leaves (6 of 10 samples). Cylindrospermopsin was detected in all saliva and leaf samples and 7 of 10 nut/husks. Salivary cylindrospermopsin levels were significantly higher in current chewers of betel quid (i.e., crushed Areca catechu nut wrapped in Piper betle leaf) compared to those chewing Areca nut alone. Anabaenopeptin was detected in saliva (10 of 25 samples), all leaf samples, and 7 of 10 nut/husks. Salivary anabaenopeptin concentration was weakly, albeit significantly, correlated with oral Cyanobacteria relative abundance.

DISCUSSION

Our study demonstrates that Cyanobacteria can contaminate AN/BQ plants and expose chewers to potent hepatotoxins. With worldwide increases in climate-related overgrowth of Cyanobacteria, our findings have broad implications for cancer risk across populations.

Development of methods to estimate microcystins removal and water treatment resiliency using mechanistic risk modelling

Drinking water treatment processes are capable of removing microcystins but consistent operation of processes optimized for cyanobacterial harmful algal bloom (cHAB) conditions is not fiscally feasible. Therefore, utilities must ready themselves and start the cHAB processes as a reactionary response. Predictive analytics and modelling are impactful tools to prepare water systems for cHABs, but are still in early stages of development. Until those prospective models are completed, a method to determine best actions in advance of a bloom event thus improving system resiliency is needed. In this study, an adaptation of the quantitative microbial risk analysis (QMRA) methodology was applied to develop this method. This method and resulting models were developed around the Toledo (Ohio, USA) water crisis of 2014, but being mechanistic, they are easily adaptable to other systems' process operations data. Results from this internally validated model demonstrate how rapid action using both powdered activated carbon and measured increases in chlorine dose can mitigate health risks. Our research also demonstrates the importance of modelling the cellular status of the toxins (toxins either in an intact cell or in the water from a lysed cell). Risks were characterized using hazard quotients (HQ) and at the peak of the crisis ranged from a minimum of 0.00244 to a maximum of 2.84 for adults. In simulations where cHAB-specific treatment was used this decreased to 0.00057 and 0.236 respectively. We further outline how this methodology can be used to simulate water system resiliency to likely and aberrant microbial hazard events to plan for the best interventions to protect public health. This method can be used for other hazards expected to be variable in the future, where system prepatory planning is critical to continued public health protection. Considering the water quantity and quality fluctuations occurring and likely to intensify under climate change, this type of computationally supported preparedness is vital to maintaining robust water system resiliency.

Liver cancer mortality over six decades in an epidemic area: what we have learned

Background and aims:

Liver cancer is one of the most dominant malignant tumors in the world. The trends of liver cancer mortality over the past six decades have been tracked in the epidemic region of Qidong, China. Using epidemiological tools, we explore the dynamic changes in age-standardized rates to characterize important aspects of liver cancer etiology and prevention.

Methods

Mortality data of liver cancer in Qidong from 1958 to 1971 (death retrospective survey) and from 1972 to 2017 (cancer registration) were tabulated for the crude rate (CR), and age-standardized rate and age-birth cohorts. The average annual percentage change was calculated by the Joinpoint Regression Program.

Results

The natural death rate during 1958–2017 decreased from 9‰ to 5.4‰ and then increased to 8‰ as the population aged; cancer mortality rates rose continuously from 57/10⁵ to 240/10⁵. Liver cancer mortality increased from 20/10⁵ to 80/10⁵, and then dropped to less than 52/10⁵ in 2017. Liver cancer deaths in 1972–2017 accounted for 30.53% of all cancers, with a CR of 60.48/10⁵, age-standardized rate China (ASRC) of 34.78/10⁵, and ASRW (world) of 45.71/10⁵. Other key features were the CR for males and females of 91.86/10⁵ and 29.92/10⁵, respectively, with a sex ratio of 3.07:1. Period analysis showed that the ASRs for mortality of the age groups under 54 years old had a significant decreasing trend. Importantly, birth cohort analysis showed that the mortality rate of liver cancer in 40–44, 35–39, 30–34, 25–29, 20–24, 15–19 years cohort decreased considerably, but the rates in 70–74, and 75+ increased.

Conclusions

The crude mortality rate of liver cancer in Qidong has experienced trends from lower to higher levels, and from continued increase at a high plateau to most recently a gradual decline, and a change greatest in younger people. Many years of comprehensive prevention and intervention measures have influenced the decline of the liver cancer epidemic in this area. The reduction of intake levels of aflatoxin might be one of the most significant factors as evidenced by the dramatic decline of exposure biomarkers in this population during the past three decades.

Microcystis toxin-mediated tumor promotion and toxicity lead to shifts in mouse gut microbiome

Microcystins (MCs) are the most prevalent cyanotoxins reported in freshwater. While numerous studies have examined the toxicological impacts of MCs on mammalian systems, very few have examined the chronic impacts of MCs on the gut microbiome of exposed organisms. Our understanding of the relationship of MCs, especially lysed toxic cyanobacteria, and the gut microbiota is very limited. The objective of this study was to determine the impacts of MC-LR and Microcystis lysate ingestion on the gut microbiome in a hepatocellular carcinoma mouse model, simulating a high-risk population and exposure at an environmentally relevant MC level. Mice were assigned to 4 groups (MC-LR; Microcystis lysate; Negative control; Positive (liver carcinogen) control). Fecal samples were collected every 8 weeks. Bacterial community and colony counts were analyzed. The abundance of Firmicutes in the positive control and lysate group was higher than the negative control and MC group. Exposure to MC-LR or lysate was associated with significantly decreased bacterial diversity. A distinct separation of the three groups (MC-LR/lysate/carcinogen) from the negative was much more apparent in their gut microbiome as the exposure time increased. The MC-LR and lysate groups showed gut microbiome structure responding to lipid metabolism disturbance and high stress. Bacterial colony count was significantly lower in all the treated groups than the negative control. Our study highlights that chronic exposure to MC-LR and Microcystis lysate negatively impacts gut microbiome succession and altered the bacterial community structure into the one similar to the carcinogen group, which may indicate that the change favors progression of hepatocellular carcinoma. In a future study, more in-depth investigation is warranted to better understand the liver-gut nexus in promoting liver cancer among those exposed to MC and toxic cyanobacteria.

Assessment of diagnostic biomarkers of liver injury in the setting of microcystin-LR (MC-LR) hepatotoxicity

Microcystin-leucine arginine (MC-LR) is a potent liver toxin produced by freshwater cyanobacteria, also known as blue-green algae. While harmful algal blooms are increasing in frequency and severity worldwide, there is still no established method for the diagnosis and assessment of MC-LR induced liver damage. The guidelines for MC-LR safe exposure limits have been previously established based on healthy animal studies, however we have previously demonstrated that pre-existing non-alcoholic fatty liver disease (NAFLD) increases susceptiblity to the hepatotoxic effects of MC-LR. In this study, we sought to investigate the suitability of clinically used biomarkers of liver injury, specifically alanine aminotransferase (ALT) and alkaline phosphatase (ALP), as potential diagnostic tools for liver damage induced by chronic low dose administration of MC-LR in the setting of pre-existing NAFLD. In our Leprdb/J mouse model of NAFLD, we found that while MC-LR induced significant histopathologic damage in the setting of NAFLD, gene expression of ALT and ALP failed to increase with MC-LR exposure. Serum ALT and ALP also failed to increase with MC-LR exposure, except for a moderate increase in ALP with the highest dose of MC-LR used (100 μg/kg). In HepG2 human liver epithelial cells, we observed that increasing MC-LR exposure levels do not lead to an increase in ALT or ALP gene expression, intracellular enzyme activity, or extracellular activity, despite a significant increase in MC-LR induced cytotoxicity. These findings demonstrate that ALT and ALP may be unsuitable as diagnostic biomarkers for MC-LR induced liver damage.

A lack of association between increases in gastrointestinal, liver, and urologic cancers and cyanobacterial contamination of fresh water lakes in Manitoba

Cyanobacteria or blue-green algae are becoming increasingly abundant in North American fresh water lakes. Toxins produced by cyanobacteria have been associated with gastrointestinal injury, liver failure, and nephrotoxicity. They have also been implicated in the pathogenesis of gastrointestinal and liver cancers. The purpose of the present study was to determine whether the incidence rates of gastrointestinal, liver, and urologic cancers are increasing in the province of Manitoba and, if so, whether these increases spatially and/or temporally correlate with areas where cyanobacterial contamination of fresh water lakes have been identified. Cancer incidence data were obtained from the Manitoba Cancer Registry. Cyanobacterial contamination data, as reflected by microcystin toxin concentrations, were available from the Manitoba Water Stewardship. ArcGIS mapping was employed to document spatial and temporal relationships between cancer incidence and cyanobacterial data. The results revealed that although the incidence rates for all three cancers have increased over the past 20-25 years, these increases were not disproportionally higher in zones with high microcystin toxin determinations. The results of this study argue against increased exposure to cyanotoxins as an explanation for the increase in gastrointestinal, liver and urologic cancers in Manitoba.

Zooplankton as Indicator of the Ecological State of Protected Aquatic Ecosystems (Lake Borovoe, Burabay National Nature Park, Northern Kazakhstan)

The enrichment of the protected Borovoe Lake with nutrients has taken place within the last 100 years, from the moment the first resort was formed on its shores. The purpose of this study was to assess the current ecological state of Borovoe based on the structure of zooplankton. According to the chemical data, in the summer of 2019, the content of nutrients in the water was, relatively, not high; the content of heavy metals was very low. Twenty-seven species were found in zooplankton. The average abundance of zooplankton was 988.8 thousand ind./m3 with a biomass of 1.52 g/m3. Rotifera dominated. Cladocera sub-dominated. The Shannon index values were 2.31 bit/ind. and 2.57 bit/mg; the values of Clarke’s W-statistics and Δ-Shannon were negative. The abundance of zooplankton increased more than nine times, but the average individual mass of an organism decreased from 0.0112 to 0.0016 mg over the past decade. Despite the relatively low content of nutrients, the structure of zooplankton demonstrated that the nutritional load on Lake Borovoe is currently close to critical. Statistical mapping of the data and redundancy analysis (RDA) showed that the primary source of lake pollution is the village of Borovoe and sanatoriums located on the southeast and northwest coasts.

Relationship between cyanobacterial bloom impacted drinking water sources and hepatocellular carcinoma incidence rates

Freshwater cyanobacterial blooms have increased in geographic distribution and intensity in recent decades worldwide. Cyanotoxins produced by many of these blooms, such as microcystins, are observed to play a role in tumor promotion and have been associated with increased liver cancer rates at the population level. Exposure occurs primarily via contaminated water (ingestion, inhalation, dermal contact), either from treated drinking water or during recreation in impacted surface waters; additional sources of exposure include consumption of fresh produce grown in cyanotoxin-contaminated environments or through the consumption of seafood caught in bloom-impacted waters. The current ecological study investigates whether populations served by cyanobacterial bloom-impacted surface waters for their drinking water source have higher hepatocellular carcinoma (HCC) incidence rates than those served by non-impacted surface waters and groundwater. Census tract level cancer incidence in the state of Ohio, United States was modeled using a negative binomial generalized linear model, controlling for differences in demographic composition (e.g. age, race, and income) at the census tract level. Presence of cyanobacterial blooms in surface waters was estimated using satellite multi-spectral remote sensing and in situ public water system cyanotoxin monitoring data. Census tracts estimated to be served by bloom-impacted surface waters had 14.2% higher HCC incidence rates than those served by non-bloom-impacted surface waters (incidence rate ratio, IRR: 1.142; 95% CI: 1.037-1.257). Additionally, these bloom-impacted census tracts had a 17.4% higher HCC incidence rate as compared to those estimated to receive drinking water from a groundwater source (IRR: 1.174; 95% CI: 1.101-1.252). No statistical difference was found in HCC incidence rates when comparing areas presumed to be served by non-bloom-impacted surface waters and those presumed to be served by groundwater sources. An important consideration for environmental justice, areas estimated to be served by bloom-impacted surface waters had higher levels of poverty and included a higher percentage of racial and ethnic minority populations than areas served by groundwater. These findings support the need for additional in-depth research into the potential hepatic carcinogenicity and exposures of cyanotoxins in those areas where severe blooms are chronically observed.

Seasonal changes in the bacterial community structure of three eutrophicated urban lakes in Mexico city, with emphasis on Microcystis spp

Artificial urban lakes commonly have physicochemical conditions that contribute to rapid anthropogenic eutrophication and development of cyanobacterial blooms. Microcystis is the dominat genus in most freshwater bodies and is one of the main producter of microcystins. Using 454-pyrosequencing we characterized the bacterial community, with special emphasis on Microcystis, in three recreational urban lakes from Mexico City in both wet and dry seasons. We also evaluated some physicochemical parameters that might influence the presence of Microcystis blooms, and we associated the relative abundance of heterotrophic and autotrophic bacterial communities with their possible metabolic capacities. A total of 14 phyla, 18 classes, 39 orders, 53 families and 48 bacterial genera were identified in both seasons in the three urban lakes. Cyanobacteria had the highest relative abundance followed by Proteobacteria and Actinobacteria. Microcystis was the dominant taxon followed by Arthrospira, Planktothrix and Synechococcus. We also found heterotrophic bacteria associated with the blooms, such as Rhodobacter, Pseudomonas, Sphingomonas and, Porphyrobacter. The highest richness, diversity and dominance were registered in the bacterial community of the Virgilio Uribe Olympic Rowing-Canoeing Track in both seasons, and the lowest values were found in the Chapultepec Lake. The canonical correspondence analysis showed that dissolved oxygen and NO₃-N concentrations might explain the presence of Microcystis blooms. The metabolic prediction indicated that these communities are involved in photosynthesis, oxidative phosphorylation, methane metabolism, carbon fixation, and nitrogen and sulfur metabolism. The lakes studied had a high prevalence of Microcystis, but average values of microcystins did not exceed the maximum permissible level established by the United States Environmental Protection Agency for recreational and cultural activities. The presence of cyanobacteria and microcystins at low to moderate concentrations in the three lakes could result in ecosystem disruption and increase animal and human health risks.

Drinking water treatment residuals from cyanobacteria bloom-affected areas: Investigation of potential impact on agricultural land application

In cyanobacteria bloom-affected areas, drinking water treatment processes are optimized to ensure the absence of cyanotoxins in their finished water. A concern about the sludge generated from water treatment has emerged because the removed cyanotoxins and cyanobacteria can get concentrated in the sludge, called water treatment residuals (WTR), and these WTR are often applied on land for beneficial purposes. However, the impact of WTR from bloom-affected areas on the agricultural application and public health is hardly reported. The objective of this study was to characterize bloom-affected WTR by focusing on cyanotoxins, toxin-producing cyanobacteria, microbiomes, and resistome profiles. In addition, the fate of WTR-originated microcystin in crops and soil was examined. WTR samples were obtained from a bloom-affected area in Ohio, USA in November 2017. Cyanotoxins and toxin-producing cyanobacteria were quantified with the enzyme-linked immunosorbent assay and droplet digital PCR, respectively. Microbiome and resistome were determined with Nanopore sequencing. Cyanotoxin concentrations were measured: microcystin (259 μg/kg), saxitoxin (0.16 μg/kg), anatoxin-a (not detected), and β-Methylamino-L-alanine (BMAA) (575 μg/kg). MC-producing cyanobacteria concentrations were determined: Planktothrix (5.3 × 10⁷ gene copies/g) and Microcystis (3.3 × 10³ gene copies/g). Proteobacteria was the most predominant and Planktothrix phage was a remarkably dominant virus in the WTR microbiome. Aminoglycoside resistance was the most abundant class, and antibiotic resistance was found in multiple pathogens (e.g. Mycobacterium). WTR land application was simulated by growing carrots with a mixture of WTR and soil in a greenhouse. At harvest, ~80% of WTR-originated microcystin was found in the soil (83-96 μg/kg) and 5% accumulated in carrots (19-28 μg/kg). This study provides the first insight into the cyanotoxin, microbiome, and resistome profile of bloom-affected WTR. Our finding suggests that careful WTR management is needed for the beneficial use of WTR for protecting agricultural environments, especially soil and groundwater, and food safety.

Chronic Microcystin-LR Exposure Induces Abnormal Lipid Metabolism via Endoplasmic Reticulum Stress in Male Zebrafish

In order to explore effects of low levels of continuous microcystin-LR (MC-LR) (a cyanotoxin) exposure on hepatic lipid metabolism on the basis of the endoplasmic reticulum stress (ERS) pathway, we exposed adult male zebrafish to MC-LR (0, 1, 5, and 25 μg/L) for 60 days, and hepatic histopathology as well as lipid metabolic parameters were determined with mRNA levels of ERS signal molecules and downstream factors, along with genes associated with lipid metabolism in zebrafish liver. The results revealed that prolonged exposure to MC-LR remarkably altered the levels of hepatic total cholesterol and triglyceride and led to hepatic steatosis, which was also confirmed by hepatic cytoplasmic vacuolization in Hematoxylin/eosin (H&E) stain and lipid droplet accumulation in Oil Red O stain. The severity of hepatic damage and lipidation was increased in a dose-related manner. MC-LR exposure significantly upregulated transcriptional levels of ERS markers including hspa5, mapk8, and chop, indicating the occurrence of ERS in the liver of zebrafish. Concurrently, MC-LR significantly improved mRNA expression of unfolded protein response (UPR) pathway-related genes including atf6, eif2ak3, ern1, and xbp1s, suggesting that all of the three UPR branches were activated by MC-LR. MC-LR also induced significant upregulation of downstream lipid metabolism-related factors and genes including srebf1, srebf2, fatty acid synthase (fasn), acetyl-CoA carboxylase (acaca), stearoyl-CoA desaturase (scd), HMG CoA reductase (hmgcra), and HMG CoA synthase (hmgcs1), and downregulation of genes associated with lipolysis such as triglyceride hydrolase gene (atgl), hormone-sensitive enzyme gene (hsla), and carnitine palmitoyltransferase gene (cpt1aa). Our present results indicated that the cause of hepatic lipid accumulation by MC-LR was mainly by upregulating lipogenic and cholesterol genes but downregulating the expression of lipolytic genes through the induction of srebf1 and srebf2, which were involved in the activation of ERS signal pathways.

Characterization of the gut microbiota of Nicaraguan children in a water insecure context

OBJECTIVES

The gut microbiota varies across human populations. The first years of life are a critical period in its development. While delivery mode and diet contribute to observed variation, the additional contribution of specific environmental factors remains poorly understood. One factor is waterborne enteric pathogen exposure. In this pilot study, we explore the relationship between household water security and the gut microbiota of children.

METHODS

From Nicaraguan households (n = 39), we collected drinking water samples, as well as fecal samples from children aged one month to 5.99 years (n = 53). We tested water samples for total coliforms (CFU/mL) and the presence of common enteric pathogens. Composition and diversity of the gut microbiota were characterized by 16S rRNA sequencing. Households were classified as having drinking water that was "low" (<29 CFU/mL) or "high" (≥29 CFU/mL) in coliforms. We used permutational analyses of variance and Mann-Whitney U-tests to identify differences in the composition and diversity of the gut microbiota of children living in these two home types.

RESULTS

Insecure access led households to store drinking water and 85% tested positive for coliforms. High concentrations of Salmonella and Campylobacter were found in water and fecal samples. Controlling for age, the gut microbiota of children from high coliform homes were compositionally different and less diverse than those from low coliform homes.

CONCLUSIONS

Results indicate that research exploring the ways water insecurity affects human biology should consider the gut microbiome and that investigations of inter-population variation in the gut microbial community of children should consider pathogen exposure and infection.

Harmful algal blooms and liver diseases: focusing on the areas near the four major rivers in South Korea

Freshwater harmful algal blooms (HABs) have become a global concern because blooms contain cyanotoxins that can cause liver damage and other negative health impacts. In South Korea, HABs have been frequently observed along the major rivers (Han, Geum, Nakdong, and Youngsan) in recent years. However, there are hardly any studies that report a linkage between HABs and human health, especially along the four major rivers where dams, weirs, and reservoirs were constructed, and sediments were dredged under the Four Major Rivers Project (FMRP) that ended in 2012. The goals of this study were to summarize spatial distribution patterns of HABs and investigate a potential association between HABs and liver diseases. Chlorophyll-a concentration was used to estimate bloom intensity since it was the only available bloom-related parameter that covers the entire rivers. Liver disease data (ICD-10 codes: K71-K77) were sorted by administrative districts. Generalized linear mixed model was used to analyze the bloom, liver diseases, and population data (2005-2016). The results show that chlorophyll-a levels significantly increased since 2013, except Han River region. There was a significant association between HAB intensity and incidence rate of liver diseases, except Han River area, and the extent of association significantly increased after the completion of the FMRP. For future studies, more in-depth epidemiological investigations are warranted in those areas to accurately determine more specific associations between HABs and liver diseases as well as other bloom-related diseases and symptoms. In addition, identification of major exposure pathways to cyanotoxins is needed to better protect public health in those bloom-affected areas.

Meteorological and Nutrient Conditions Influence Microcystin Congeners in Freshwaters

Cyanobacterial blooms increasingly impair inland waters, with the potential for a concurrent increase in cyanotoxins that have been linked to animal and human mortalities. Microcystins (MCs) are among the most commonly detected cyanotoxins, but little is known about the distribution of different MC congeners despite large differences in their biomagnification, persistence, and toxicity. Using raw-water intake data from sites around the Great Lakes basin, we applied multivariate canonical analyses and regression tree analyses to identify how different congeners (MC-LA, -LR, -RR, and -YR) varied with changes in meteorological and nutrient conditions over time (10 years) and space (longitude range: 77°2'60 to 94°29'23 W). We found that MC-LR was associated with strong winds, warm temperatures, and nutrient-rich conditions, whereas the equally toxic yet less commonly studied MC-LA tended to dominate under intermediate winds, wetter, and nutrient-poor conditions. A global synthesis of lake data in the peer-reviewed literature showed that the composition of MC congeners differs among regions, with MC-LA more commonly reported in North America than Europe. Global patterns of MC congeners tended to vary with lake nutrient conditions and lake morphometry. Ultimately, knowledge of the environmental factors leading to the formation of different MC congeners in freshwaters is necessary to assess the duration and degree of toxin exposure under future global change.

Effects of road salt on microbial communities: Halophiles as biomarkers of road salt pollution

Increased use of salting to de-ice roadways, especially in urban areas, is leading to elevated salinity levels in soil as well as surface- and ground water. This salt pollution may cause long-term ecological changes to soil and aquatic microbial communities. In this study, we examined the impact on microbial communities in soils exposed to urban road salt runoff using both culturing and 16S amplicon sequencing. Both methods showed an increase in halophilic Bacteria and Archaea in samples from road salt-exposed areas and suggested that halophiles are becoming persistent members of microbial communities in urban, road salt-impacted soils. Since salt is a pollutant that can accumulate in soils over time, it is critical to begin assessing its impact on the environment immediately. Toward this goal, we have developed a facile semi-quantitative assay utilizing halophilic microbes as biomarkers to evaluate on-going salt pollution of soils.

Epigenetic inactivation of LHX6 mediated microcystin-LR induced hepatocarcinogenesis via the Wnt/β-catenin and P53 signaling pathways

Microcystins (MCs) have been shown to be carcinogenic by animal and cellular experiments and found to be associated with the development of human hepatocellular carcinoma (HCC) through epidemiological studies. However, the molecular mechanism of microcystin-LR (MC-LR) induced HCC is still unclear. This study is determined to clarify the role and mechanism of LHX6 in MC-LR-induced hepatocarcinogenesis. Using the previously established MC-LR-induced malignant transformation model in L02 cells, we screened out LHX6, homeobox gene that was significantly changed. We found that LHX6 was significantly down-regulated in MC-LR treated L02 cells and the liver tissue of rats treated for 35 weeks with 10 μg/kg body weight of MC-LR. Expression of LHX6 in human tumor tissue was significantly down-regulated in high MC-LR-exposure group. LHX6 was hypermethylated in MC-LR treated L02 cells and up-regulated after treatment with 10 μM of 5-aza-2'-deoxycytidine. Furthermore, overexpression of LHX6 inhibited proliferation, invasion and migration of malignantly transformed L02 cells in vitro and in vivo, while knockdown of LHX6 resulted in an opposite phenotype. In addition, we found that up-regulation of P53 and Bax resulted in apoptosis, and that down-regulation of CTNNB1 and MMP7 led to migration of MC-LR treated L02 cells. Blockade of P53 and CTNNB1 by its inhibitor significantly diminished the effect of LHX6. These genes were working together during the process of MC-LR-induced hepatocarcinogenesis. Our study demonstrated for the first time that LHX6 gene expression is regulated by DNA methylation and can inhibit the proliferation, invasion and migration through Wnt/β-catenin and P53 signaling pathways during the MC-LR-induced hepatocarcinogenesis. This result may suggest that LHX6 gene can be used as a potential target gene and a biomarker for liver cancer treatment.

Examination of Human Health Impacts Due to Adverse Climate Events Through the Use of Vulnerability Mapping: A Scoping Review

Government officials, health professionals, and other decision makers are tasked with characterizing vulnerability and understanding how populations experience risks associated with exposure to climate-related hazards. Spatial analyses of vulnerable locations have given rise to climate change vulnerability mapping. While not a new concept, the spatial analyses of specific health outcomes remain limited. This review explores different methodologies and data that are used to assess vulnerability and map population health impacts to climate hazards. The review retrieved scholarly articles and governmental reports concerning vulnerability mapping of human health to the impacts of climate change in the United States, published in the last decade. After review, 37 studies were selected for inclusion. Climate-related exposures were distributed across four main categories, including: high ambient temperatures; flood hazards; vector-borne diseases; and wildfires. A number of different methodologies and measures were used to assess health vulnerability to climate-related hazards, including heat vulnerability indices and regression analyses. Vulnerability maps should exemplify how variables measuring the sensitivity and adaptive capacity of different populations help to determine the potential for climate-related hazards to have an effect on human health. Recommendations address methodologies, data gaps, and communication to assist researchers and stakeholders in directing adaptations to their most efficient and effective use.

Sub-Chronic Microcystin-LR Liver Toxicity in Preexisting Diet-Induced Nonalcoholic Steatohepatitis in Rats

Microcystin-LR (MCLR) is a hepatotoxic cyanotoxin reported to cause a phenotype similar to nonalcoholic steatohepatitis (NASH). NASH is a common progressive liver disease that advances in severity due to exogenous stressors such as poor diet and toxicant exposure. Our objective was to determine how sub-chronic MCLR toxicity affects preexisting diet-induced NASH. Sprague-Dawley rats were fed one of three diets for 10 weeks: control, methionine and choline deficient (MCD), or high fat/high cholesterol (HFHC). After six weeks of diet, animals received vehicle, 10 µg/kg, or 30 µg/kg MCLR via intraperitoneal injection every other day for the final 4 weeks. Incidence and severity scoring of histopathology endpoints suggested that MCLR toxicity drove NASH to a less fatty and more fibrotic state. In general, expression of genes involved in de novo lipogenesis and fatty acid esterification were altered in favor of decreased steatosis. The higher MCLR dose increased expression of genes involved in fibrosis and inflammation in the control and HFHC groups. These data suggest MCLR toxicity in the context of preexisting NASH may drive the liver to a more severe phenotype that resembles burnt-out NASH.

Valuing Provision Scenarios of Coastal Ecosystem Services: The Case of Boat Ramp Closures Due to Harmful Algae Blooms in Florida

Ecosystem service flows may change or disappear temporarily or permanently as a result of environmental changes or ecological disturbances. In coastal areas, ecological disturbances caused by toxin-producing harmful algae blooms can impact flows of ecosystem services, particularly provisioning (e.g., seafood harvesting) and cultural services (e.g., recreation). This study uses a random utility model of recreational boating choices to simulate changes in the value of cultural ecosystem services provided by recreation in coastal ecosystems resulting from prolonged ecological disturbances caused by harmful algae blooms. The empirical application relies on observed trips to 35 alternative boat access ramps in Lee County, an important marine access destination in southwest Florida. Results indicate that reduced boating access from harmful algae blooms may have resulted in losses of $3 million for the 2018 blooms, which lasted from the end of June to the end of September.

Nonalcoholic fatty liver disease alters microcystin-LR toxicokinetics and acute toxicity

Microcystin-LR (MCLR) is a cyanotoxin produced by blue-green algae that causes liver and kidney toxicities. MCLR toxicity is dependent on cellular uptake through the organic anion transporting polypeptide (OATP) transporters. Nonalcoholic fatty liver disease (NAFLD) progresses through multiple stages, alters expression of hepatic OATPs, and is associated with chronic kidney disease. The purpose of this study was to determine whether NAFLD increases systemic exposure to MCLR and influences acute liver and kidney toxicities. Rats were fed a control diet or two dietary models of NAFLD; methionine and choline deficient (MCD) or high fat/high cholesterol (HFHC). Two studies were performed in these groups: 1) a single dose intravenous toxicokinetic study (20 μg/kg), and 2) a single dose intraperitoneal toxicity study (60 μg/kg). Compared to control rats, plasma MCLR area under the concentration-time curve (AUC) in MCD rats doubled, whereas biliary clearance (Clbil) was unchanged; in contrast, plasma AUC in HFHC rats was unchanged, whereas Clbil approximately doubled. Less MCLR bound to PP2A was observed in the liver of MCD rats. This shift in exposure decreased the severity of liver pathology only in the MCD rats after a single toxic dose of MCLR (60 μg/kg). In contrast, the single toxic dose of MCLR increased hepatic inflammation, plasma cholesterol, proteinuria, and urinary KIM1 in HFHC rats more than MCLR exposed control rats. In conclusion, rodent models of NAFLD alter MCLR toxicokinetics and acute toxicity and may have implications for liver and kidney pathologies in NAFLD patients.

Microcystin-LR in peripheral circulation worsens the prognosis partly through oxidative stress in patients with hepatocellular carcinoma

Prognostic significance of serum microcystin in hepatocellular carcinoma has not been well investigated. The aim of the study was to reveal the relationship between serum microcystin-LR and prognosis in these patients. There were 650 early-stage hepatitis B-induced hepatocellular carcinoma patients, who were not affected by hepatitis C, cirrhosis, heavy drinking or excessive aflatoxin exposure. All of them underwent hepatectomy and were followed up for 5 years. Tumor relapse and overall death were recorded. Blood specimens were collected on admission and at the time of relapse. Serum levels of microcystin-LR and fluorescent oxidation products (FlOP_360, FlOP_320 and FlOP_400) were measured separately using enzyme-linked immunosorbent assay and fluorescence spectrometry. Multifactorial COX regression analysis suggested that serum microcystin-LR ≥ 0.97 ng/ml was associated with the increased risk of the tumor relapse (HR: 1.53, 95% CI: 1.35-1.77) and serum microcystin-LR ≥ 1.09 ng/ml was related to the higher risk of the overall death (HR: 1.58, 95% CI: 1.35-1.84) in the follow-up period. Furthermore, there was a linear relationship between serum level of microcystin-LR and serum levels of FlOP_360, FlOP_320 and FlOP_400 (P = 0.001, P = 0.023, P = 0.047). Serum levels of these fluorescent oxidation products were also higher in the patients with tumor relapse (P < 0.001, P < 0.001, P = 0.001) or overall death (P < 0.001, P = 0.001, P = 0.002) compared with the remaining patients. Serum microcystin-LR independently worsens the prognosis partly through promoting oxidative stress in patients with hepatocellular carcinoma.

Simulation of Sedimentation in Lake Taihu with Geostationary Satellite Ocean Color Data

In this study, the goal is to estimate the sedimentation on the bottom bed of Lake Taihu using numerical simulation combined with geostationary satellite ocean color data. A two-dimensional (2D) model that couples the dynamics of shallow water and sediment transport is presented. The shallow water equations are solved using a semi-implicit finite difference method with an Alternating Direction Implicit (ADI) method. Suspended sediment transport is simulated by solving the general convection-diffusion equation with resuspension and deposition terms using a second-order explicit central difference method in space and two-step Adams–Bashforth method in time. Moreover, the total suspended particulate matter (TSM) is retrieved by the world’s first geostationary satellite ocean color sensor Geostationary Ocean Color Imager (GOCI) using atmospheric correction algorithm for turbid waters using ultraviolet wavelengths (UV-AC) and regional empirical TSM algorithm. The 2D model and GOCI-retrieved TSM are applied to study the sediment transport and sedimentation in Lake Taihu. Validation results show rationale TSM concentration retrieved by GOCI, and the simulated TSM concentrations are consistent with GOCI observations. In addition, simulated sedimentation results reveal the dangerous locations that must be observed and desilted.

Identifying aerosolized cyanobacteria in the human respiratory tract: A proposed mechanism for cyanotoxin-associated diseases

Cyanobacteria produce harmful toxins that have been associated with several acute conditions and chronic human diseases, like gastroenteritis, non-alcoholic liver disease, and amyotrophic lateral sclerosis. Aerosol from waterbodies appears to be a likely mechanism for exposure. We conducted a study of human biospecimens focused on the cyanobacterial aerosilization process by evaluating the extent to which cyanobacteria can invade the human respiratory tract. Our study suggests that humans routinely inhale aerosolized cyanobacteria, which can be harbored in the nostrils and the lungs. Using PCR, cyanobacteria were found at high frequencies in the upper respiratory tract (92.20%) and central airway (79.31%) of our study subjects. Nasal swabs were not predictive of bronchoalveolar lavage (BAL) when detecting inhaled cyanobacteria. Interestingly, we found no evidence that time of year was a significant factor for cyanobacteria positivity (BAL cytology p = 1.0 and PCR p = 1.0); (nasal swab cytology p = 0.051 and PCR p = 0.65). Additionally, we found that proximity to a waterbody was not a significant factor for cyanobacteria positivity in BAL and nasal swabs collected during cyanobacteria bloom season [May-October] (p = 0.46 and p = 0.38). These data suggest that cyanobacteria exposure may be a prevalent and chronic phenomenon not necessarily restricted to waterbodies alone. Sources of indoor exposure warrant future investigation. Given the widespread prevalence of cyanobacterial exposure in the airway, investigation of the aerosol spread of cyanotoxins, more specifically, is warranted. Our findings are consistent with the hypothesis that aerosol is a significant route for cyanobacteria exposure, and thus a likely route of transmission for cyanotoxin-associated human diseases.

Assessment of physiological responses and growth phases of different microalgae under environmental changes by Raman spectroscopy with chemometrics

The assessment for cell physiology and growth phases of microalgae plays important roles in ecological and environmental fields since it can be used to forecast water eutrophication level worldwidely. Herein, growth phases and environmental conditions of microalgae were assessed by combining resonance Raman mapping spectroscopy with multivariate analysis methods. And, primary Raman characteristic peaks of microalgae were mined with two-dimensional synchronous spectra. Thereafter, algal growth phases and environmental conditions of microalgae were preliminary classified with different tendencies of characteristic Raman peaks by unsupervised principal component analysis (PCA) and support vector machine (SVM) methods. Our results demonstrated that resonance Raman mapping spectroscopy with PCA and SVM classification models can be used to assess algal growth phases and preliminary predict environmental conditions with characteristic Raman spectra of microalgae in water bodies.

Distinctive pattern of AHNAK methylation level in peripheral blood mononuclear cells and the association with HBV-related liver diseases

The purpose of this study was to investigate the correlation between AHNAK methylation level in peripheral blood mononuclear cells (PBMC) and the progression of hepatitis B virus (HBV)‐related liver disease. Bioinformatics methods were applied to evaluate the AHNAK methylation level in PBMC and T cells at different stages of HBV related liver disease, to investigate the correlation between AHNAK methylation and clinical features, as well as to compare the methylation site of AHNAK in cancer tissues and adjacent tissues. Subsequently, the differentially expressed gene analysis technique was used to analyze the liver disease‐related genes and immune‐related pathways in hepatitis B patients with different pathological changes. Finally, promoter methylation and mRNA expression of AHNAK gene in liver cancer and adjacent tissues were determined by quantitative polymerase chain reaction (Q‐PCR), and the diagnostic value of AHNAK methylation level in hepatopathy was evaluated by receiver operating characteristic (ROC) curve. The promoter methylation level of AHNAK gene in PBMCs decreased with the progression of HBV‐related liver disease, and showed significant difference among the patients with various HBV‐related liver diseases (P = 0.0001). The AHNAK methylation level in PBMCs and T cells was negatively associated with age, white blood cell count, CREA, drinking, and positively associated with APTT and HbsAg. Higher mRNA expression of AHNAK was found in liver cancer tissues than that of adjacent tissues (P < 0.001), and the methylation level in PBMC decreased with the progression of hepatitis B‐related liver disease. The area under the ROC curve (ROC) was 0.883 (P < 0.001) in diagnosis of chronic hepatitis B (CHB), 0.885 (P < 0.001) in diagnosis of compensatory liver cirrhosis, 0.955 (P < 0.001) in diagnosis of decompensated liver cirrhosis, 0.981 (P < 0.001) in diagnosis of hepatocellular carcinoma. Our results revealed that AHNAK methylation level in peripheral blood decreases with the progression of hepatitis B‐related liver disease. This provided a potential differential diagnostic method for HBV‐related hepatopathies, and thus an early detective tool for liver cancer.