Integrative investigation of hematotoxic effects induced by low doses of lead, cadmium, mercury and arsenic mixture: In vivo and in silico approach

The effect of the lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) mixture (MIX) on hematotoxicity development was investigated trough combined approach. In vivo subacute study (28 days) was performed on rats (5 per group): a control group and five groups orally exposed to increasing metal(loid) mixture doses, MIX 1- MIX 5 (mg/kg bw./day) (Pb: 0.003, 0.01, 0.1, 0.3, 1; Cd: 0.01, 0.03, 0.3, 0.9, 3; Hg: 0.0002, 0.0006, 0.006, 0.018, 0.06; As: 0.002, 0.006, 0.06, 0.18, 0.6). Blood was taken for analysis of hematological parameters and serum iron (Fe) analysis. MIX treatment increased thrombocyte/platelet count and MCHC and decreased Hb, HCT, MCV and MCH values compared to control, indicating the development of anemia and thrombocytosis. BMDIs with the narrowest width were identified for MCH [pg] (6.030E-03 - 1.287E-01 mg Pb/kg bw./day; 2.010E-02 - 4.290E-01 mg Cd/kg bw./day; 4.020E-04 - 8.580E-03 mg Hg/kg bw./day; 4.020E-03 - 8.580E-02 mg As/kg bw./day). In silico analysis showed target genes connected with MIX and the development of: anemia - ACHE, GSR, PARP1, TNF; thrombocytosis - JAK2, CALR, MPL, THPO; hematological diseases - FAS and ALAD. The main extracted pathways for anemia were related to apoptosis and oxidative stress; for thrombocytosis were signaling pathways of Jak-STAT and TPO. Changes in miRNAs and transcription factors enabled the mode of action (MoA) development based on the obtained results, contributing to mechanistic understanding and hematological risk related to MIX exposure.

The m6A reader IGF2BP1 attenuates the stability of RPL36 and cell proliferation to mediate benzene hematotoxicity by recognizing m6A modification

Benzene exposure leads to hematotoxicity, and epigenetic modification is considered to be a potential mechanism of benzene pathogenesis. As a newly discovered post-transcriptional modification, the roles of N6-methyladenosine (m6A) in benzene hematotoxicity are still unclear. m6A can only exert its gene regulatory function after being recognized by m6A reading proteins. In this study, we found that the expression of m6A reader IGF2BP1 decreased in benzene poisoning workers and in 20 μM benzene metabolite 1,4-BQ-treated AHH-1 cells. Further overexpression of IGF2BP1 in mice alleviated 50 ppm benzene-induced hematopoietic damage, suggesting that IGF2BP1 plays a critical role in benzene hematotoxicity. Next, we examined transcriptome-wide m6A methylation in vitro to search for target genes of IGF2BP1. We found that benzene metabolite 1,4-BQ treatment altered the m6A methylation levels of various genes. The comprehensive analysis of mRNA expression and m6A methylation uncovered that the hypomethylated Ribosomal Protein L36 (RPL36) and its consequent reduced expression impaired cell proliferation. Mechanically, m6A modification reduced RNA stability to down-regulate RPL36 expression. Moreover, overexpression of IGF2BP1 relieved RPL36 reduction and cell proliferation inhibition caused by benzene in vitro and in vivo by directly binding with RPL36 mRNA. In conclusion, the m6A reader IGF2BP1 attenuates the stability of RPL36 and cell proliferation to mediate benzene hematotoxicity by recognizing m6A modification. IGF2BP1 and RPL36 may be key molecules and potential therapeutic targets for benzene hematotoxicity.

Modulatory role ulexit against thiamethoxam-induced hematotoxicity/hepatotoxicity oxidative stress and immunotoxicity in Oncorhynchusmykiss

Contamination of the aquatic environment with different insecticides is a major concern in the aquatic ecosystem today. For this reason, in the designed study, Thiamethoxam (TMX) for which there is limited information on its negative effects on Oncorhynchus mykiss was investigated, its effects on hematotoxicity, oxidative status, cytotoxicity, DNA damage and apoptotic status indicators in blood/liver tissue. However, the antitoxic potential of ulexite (UX) supplementation in the elimination of TMX-mediated toxicity has been determined. LC50-96h value determined for TMX 0.73 mg/L has been determined. As a result of hematology profile, TMX application, RBC, Hgb and Hct values showed a temporal decrease compared to the control group, while increases were determined in MCV, MCH and MCHC values. It was determined that the inhibition/induction of hematological parameters was slowed down by adding UX to the medium. During the trial (48th and 96th hours), it was noted that TMX induced cortisol level, while UX supplementation slowed this induction at 48th hour. Antioxidant enzyme activities were significantly inhibited by TMX application, and MDA and MPO values increased as a result of the stimulation of ROS. It was determined that UX added to the medium showed activity in favor of antioxidants and tried to inhibit MDA and MPO levels. When Nrf-2, one of the inflammation parameters, was compared with the administration and control groups, it was determined that it inhibited depending on time, TNF-α, IL-6, DNA damage and apoptosis were induced, and UX suppressed this situation. The results obtained were evaluated as statistically meaningful. Briefly, it was determined that TMX induced oxidative damage in all tissues at 48th - 96th hours, whereas UX mitigated this situation. The results provide possible in vivo evidence that UX supplements can reduce TMX-mediated oxidative stress and tissues damage in O. mykiss blood and liver tissues.

Oxidative stress-affected ACSL1 hydroxymethylation triggered benzene hematopoietic toxicity by inflammation and senescence

Long-term benzene exposure is harmful and causes hematopoietic dysfunction. However, the mechanism of benzene hematopoietic toxicity is still unclear. Acyl-CoA Synthetase Long-Chain Family Member 1 (ACSL1) has been found to participate in the progress of a variety of benign and malignant diseases, but there is no research about its effect on benzene-induced hematopoietic toxicity. Herein, We exposed C57BL/6J mice to benzene to construct an in vivo model. Human peripheral blood mononuclear cells (THP-1 cells) were treated with benzene metabolite 1, 4-BQ to construct an in vitro model. We observed that the ACSL1 expression was upregulated both in vivo and in vitro. Moreover, inhibition of ACSL1 relieved inflammation and senescence development in vitro, suggesting that ACSL1 mediates inflammation and senescence. As for the regulation mechanism of ACSL1 expression, it is closely related to hydroxymethylation modification. This was proved by hydroxymethylated DNA immunoprecipitation (hMeDIP) experiments. Furthermore, oxidative stress influenced the hydroxymethylation process. These results showed that benzene hematopoietic toxicity occurs through the induction of oxidative stress and thus the regulation of ACSL1 hydroxymethylation, which in turn mediates inflammation and senescence. Thus, this study might be of great significance in identifying and preventing benzene exposure in the early stage.

Moderate body lipid accumulation in mice attenuated benzene-induced hematotoxicity via acceleration of benzene metabolism and clearance

Recent population and animal studies have revealed a correlation between fat content and the severity of benzene-induced hematologic toxicity. However, the precise impact of lipid deposition on benzene-induced hematotoxicity and the underlying mechanisms remain unclear. In this study, we established a mouse model with moderate lipid accumulation by subjecting the mice to an 8-week high-fat diet (45% kcal from fat, HFD), followed by 28-day inhalation of benzene at doses of 0, 1, 10, and 100 ppm. The results showed that benzene exposure caused a dose-dependent reduction of peripheral white blood cell (WBC) counts in both diet groups. Notably, this reduction was less pronounced in the HFD-fed mice, suggesting that moderate lipid accumulation mitigates benzene-related hematotoxicity. To investigate the molecular basis for this effect, we performed bioinformatics analysis of high-throughput transcriptome sequencing data, which revealed that moderate lipid deposition alters mouse metabolism and stress tolerance towards xenobiotics. Consistently, the expression of key metabolic enzymes, such as Cyp2e1 and Gsta1, were upregulated in the HFD-fed mice upon benzene exposure. Furthermore, we utilized a real-time exhaled breath detection technique to monitor exhaled benzene metabolites, and the results indicated that moderate lipid deposition enhanced metabolic activation and increased the elimination of benzene metabolites. Collectively, these findings demonstrate that moderate lipid deposition confers reduced susceptibility to benzene-induced hematotoxicity in mice, at least in part, by accelerating benzene metabolism and clearance.

Individual hematotoxicity prediction of further chemotherapy cycles by dynamic mathematical models in patients with gastrointestinal tumors

PURPOSE

Hematotoxicity is a common side-effect of cytotoxic gastrointestinal (GI) cancer therapies. An unsolved problem is to predict the individual risk therefore to decide on treatment adaptions. We applied an established biomathematical prediction model and primarily evaluated its predictive value in patients undergoing chemotherapy for GI cancers in curative intent.

METHODS

In a prospective, observational multicenter study on patients with gastro-esophageal or pancreatic cancer (n = 28) receiving myelosuppressive adjuvant or neoadjuvant chemotherapy (FLO(T) or FOLFIRINOX), individual model parameters were learned based on patients' observed laboratory values during the first chemotherapy cycle and further external data resources. Grades of hematotoxicity of subsequent cycles were predicted by model simulation and compared with observed data.

RESULTS

The most common high-grade hematological toxicity was neutropenia [19/28 patients (68%)]. For the FLO(T) regimen, individual grades of thrombocytopenia and leukopenia could be well predicted for cycles 2-4, as well as grades of neutropenia for cycle 2. Prediction accuracy for neutropenia in the third and fourth cycle differed by one toxicity grade on average. For the FOLFIRINOX-regimen, thrombocytopenia predictions showed a maximum deviation of one toxicity grade up to the end of therapy (8 cycles). Deviations of predictions were less than one degree on average up to cycle 4 for neutropenia, and up to cycle 6 for leukopenia.

CONCLUSION

The biomathematical model showed excellent short-term and decent long-term prediction performance for all relevant hematological side effects associated with FLO(T)/FOLFIRINOX. Clinical utility of this precision-medicine approach needs to be further investigated in a larger cohort.

LncRNA OBFC2A modulated benzene metabolites-induced autophagy and apoptosis by interacting with LAMP2

Exposure to benzene results in peripheral blood cell reduction, aplastic anemia, and leukemia. We previously observed that the lncRNA OBFC2A was upregulated significantly in benzene-exposed workers and correlated with reduced blood cell counts. However, the role of lncRNA OBFC2A in benzene hematotoxicity remains unclear. In this study, we discovered that lncRNA OBFC2A was regulated by oxidative stress and played roles in cell autophagy and apoptosis caused by the benzene metabolite 1,4-Benzoquinone (1,4-BQ) in vitro. Mechanistically, protein chip, RNA pull-down and FISH colocalization uncovered that lncRNA OBFC2A directly bound to LAMP2, a regulator of chaperone-mediated autophagy (CMA), and upregulated its expression in 1,4-BQ-treated cells. LncRNA OBFC2A knockdown alleviated LAMP2 overexpression caused by 1,4-BQ, which confirmed their regulatory relationship. In conclusion, we demonstrate that lncRNA OBFC2A mediates 1,4-BQ-induced apoptosis and autophagy by interacting with LAMP2. LncRNA OBFC2A could serve as a biomarker for hematotoxicity caused by benzene.

Nonlinear low dose hematotoxicity of benzene; a pooled analyses of two studies among Chinese exposed workers

BACKGROUND

Impairment of the hematopoietic system is one of the primary adverse health effects from exposure to benzene. We previously have shown that exposure to benzene at low levels (<1 ppm) affects the blood forming system and that these effects were proportionally stronger at lower versus higher levels of benzene exposure. This observation is potentially explained by saturation of enzymatic systems.

METHODS

Here we extend these analyses by detailed modeling of the exposure response association of benzene and its major metabolites (i.e. catechol, muconic acid, phenol, and hydroquinone) on peripheral white blood cell (WBC) counts and its major cell-subtypes (i.e. granulocytes, lymphocytes, and monocytes) using two previously published cross-sectional studies among occupationally exposed Chinese workers.

RESULTS

Supra-linear exposure response associations were observed between air benzene concentrations (range ∼ 0.1 - 100 ppm) and WBC counts and its cell-subtypes, with a larger than proportional decrease in cell counts at lower than at higher levels of benzene exposure. The hematotoxicity associations were largely similar in shape when the analyses were repeated with benzene urinary metabolites suggesting that enzymatic saturation is not a full explanation of the observed non-linearity with WBC endpoints.

DISCUSSION

We hypothesize that the flattening of the exposure response curve especially at higher benzene exposure levels may reflect a response by the bone marrow to maintain hematopoietic homeostasis. Toxicity to the bone marrow and an induced hyper-proliferative response could both contribute to risk of subsequently developing a hematopoietic malignancy. Additional work is needed to explore this hypothesis.

Hydroquinone triggers pyroptosis and endoplasmic reticulum stress via AhR-regulated oxidative stress in human lymphocytes

Benzene is a frequent component of environmental pollution and is abundant in petrochemicals, decorative materials, motor vehicle exhaust and cigarette smoke. Benzene is a well-known carcinogen in humans and animals, but the molecular mechanism has not yet been elucidated. Our earlier research indicated that hydroquinone (HQ), one of the main reactive metabolites of benzene, could activate aryl hydrocarbon receptor (AhR), which is essential for HQ-induced toxicity, including apoptosis and DNA damage. Since AhR is an important regulator of the immune system that integrates the environmental stimulus and immune response, we examined whether and how HQ-induced AhR activity could lead to NLRP3 inflammasome-dependent pyroptosis in JHP cells. Our results showed that HQ could cause inflammation process and resultant pyroptosis. In JHP cells, HQ also induced endoplasmic reticulum stress (ERS) by releasing excessive reactive oxygen species (ROS). The activation of pyroptosis induced by HQ treatment was reversed by an antioxidant (NAC) and an ERS inhibitor (4-PBA). Interestingly, the treatment of CH223191, an AhR inhibitor, reversed HQ-induced oxidative stress, ERS and pyroptosis. These data suggested that AhR-mediated HQ-induced ERS, ROS and inflammasome activation may play vital roles in the toxic effects of benzene. This work provides insights and prospective strategies into potential mechanisms for reducing benzene-induced hematotoxicity.

Genus unclassified_Muribaculaceae and microbiota-derived butyrate and indole-3-propionic acid are involved in benzene-induced hematopoietic injury in mice

Benzene is a group I carcinogen determined by IARC. The prevalence of benzene in occupational and general environments increases the risk of acute myeloid leukemia (AML) among workers and childhood leukemia. However, the mechanism of hematotoxicity induced by benzene remains unclear. Recently, the gut microbiota has been regarded as a pivotal part of normal and malignant hematopoiesis. Therefore, in this study, we explored the function of gut microbiota in hematopoietic injury induced by benzene by 16S rRNA sequencing. We found that benzene exposure caused bone marrow damage, hematopoietic stem and progenitor cells (HSPCs) dysfunction, and peripheral blood cell reduction. Moreover, intestinal barrier damage and gut microbiota dysbiosis were also observed in benzene-exposed mice. Interestingly, two gut flora, Lachnospiraceae_NK4A136_group and unclassified_Muribaculaceae, were significantly up-regulated and associated with hematopoietic indicators, suggesting that gut-host crosstalk might mediate benzene hematotoxicity. Microbiota-derived metabolites, such as short-chain fatty acids (SCFAs), bile acids, and tryptophan metabolites, are the primary mediators of the gut-host crosstalk. Therefore, we conducted absolute quantitative metabolomics to investigate the impact of benzene exposure on these metabolites in mice. The results showed that the concentration of SCFA butyrate, tryptophan metabolites kynurenine, and Indole-3-propionic acid (IPA) were significantly altered after benzene exposure. However, no difference was found in bile acids. Significant correlations were found between altered metabolites and hematopoietic indicators. We then investigated the flora that derived these metabolites. Lachnospiraceae_NK4A136_group and unclassified_Muribaculaceae were enriched in the butyrate metabolism and tryptophan metabolism pathways. Correlation analysis further suggested that unclassified_Muribaculaceae was positively associated with butyrate (r = 0.588, P < 0.05) and IPA (r = 0.59, P < 0.05). The above results demonstrated that unclassified_Muribaculaceae and microbiota-derived butyrate and IPA were involved in hematopoietic toxicity caused by benzene. This study provides insight into gut microbiota-derived metabolites-host crosstalk in benzene hematopoietic toxicity.

Micro- and nanoplastics: A new cardiovascular risk factor?

Exposure to micro- and nanoplastics (MNPs) is inevitable due to their omnipresence in the environment. A growing body of studies has advanced our understanding of the potential toxicity of MNPs but knowledge gaps still exist regarding the adverse effects of MNPs on the cardiovascular system and underlying mechanisms, particularly in humans. Here, we reviewed up-to-date data published in the past 10 years on MNP-driven cardiovascular toxicity and mechanisms. Forty-six articles concerning ADME (absorption, distribution, and aggregation behaviors) and toxicity of MNPs in the circulatory system of animals and human cells were analyzed and summarized. The results showed that MNPs affected cardiac functions and caused toxicity on (micro)vascular sites. Direct cardiac toxicity of MNPs included abnormal heart rate, cardiac function impairment, pericardial edema, and myocardial fibrosis. On (micro)vascular sites, MNPs induced hemolysis, thrombosis, blood coagulation, and vascular endothelial damage. The main mechanisms included oxidative stress, inflammation, apoptosis, pyroptosis, and interaction between MNPs and multiple cellular components. Cardiovascular toxicity was determined by the properties (type, size, surface, and structure) of MNPs, exposure dose and duration, protein presence, the life stage, sex, and species of the tested organisms, as well as the interaction with other environmental contamination. The limited quantitative information on MNPs' ADME and the lack of guidelines for MNP cardiotoxicity testing makes risk assessment on cardiac health impossible. Furthermore, the future directions of cardiovascular research on MNPs are recommended to enable more realistic health risk assessment.

Patterns, predictors and prognostic relevance of high-grade hematotoxicity after temozolomide or temozolomide-lomustine in the CeTeG/NOA-09 trial

PURPOSE

In the randomized phase III trial CeTeG/NOA-09, temozolomide (TMZ)/lomustine (CCNU) combination therapy was superior to TMZ in newly diagnosed MGMT methylated glioblastoma, albeit reporting more frequent hematotoxicity. Here, we analyze high grade hematotoxicity and its prognostic relevance in the trial population.

METHODS

Descriptive and comparative analysis of hematotoxicity adverse events ≥ grade 3 (HAE) according to the Common Terminology of Clinical Adverse Events, version 4.0 was performed. The association of HAE with survival was assessed in a landmark analysis. Logistic regression analysis was performed to predict HAE during the concomitant phase of chemotherapy.

RESULTS

HAE occurred in 36.4% and 28.6% of patients under CCNU/TMZ and TMZ treatment, respectively. The median onset of the first HAE was during concomitant chemotherapy (i.e. first CCNU/TMZ course or daily TMZ therapy), and 42.9% of patients with HAE receiving further courses experienced repeat HAE. Median HAE duration was similar between treatment arms (CCNU/TMZ 11.5; TMZ 13 days). Chemotherapy was more often discontinued due to HAE in CCNU/TMZ than in TMZ (19.7 vs. 6.3%, p = 0.036). The occurrence of HAE was not associated with survival differences (p = 0.76). Regression analysis confirmed older age (OR 1.08) and female sex (OR 2.47), but not treatment arm, as predictors of HAE.

CONCLUSION

Older age and female sex are associated with higher incidence of HAE. Although occurrence of HAE was not associated with shorter survival, reliable prediction of patients at risk might be beneficial to allow optimal management of therapy and allocation of supportive measures.

TRIAL REGISTRATION

NCT01149109.

Fluxapyroxad disrupt erythropoiesis in zebrafish (Danio rerio) embryos

Fluxapyroxad, a succinate dehydrogenase inhibitor (SDHI) fungicide, is commercialized worldwide to control a variety of fungal diseases. Growing evidence shows that fluxapyroxad is teratogenic to aquatic organisms. In this study, the influence of fluxapyroxad toward hematopoietic development was evaluated using zebrafish embryos which were exposed to fluxapyroxad (0.03 µM, 0.3 µM and 3 µM) from 3 h post fertilization (hpf) to 3 days post fertilization (dpf). Compared to the control groups, the hemoglobin was ectopic and decreased in response to fluxapyroxad treatment. The transcription levels of genes (hbbe1, hbbe2, and gata1a) involved in erythropoiesis were reduced after exposure to fluxapyroxad. In contrast, the distributions and expression of marker genes for myeloid lineage cells were unaffected by fluxapyroxad exposure. Our data suggested that fluxapyroxad might specifically affect erythropoiesis and hold great promise for the assessment of the toxicity of fluxapyroxad to aquatic organisms.

Let-7e-5p, a promising novel biomarker for benzene toxicity, is involved in benzene-induced hematopoietic toxicity through targeting caspase-3 and p21

Benzene is a common industrial chemical and environmental pollutant. However, the mechanism of hematotoxicity caused by exposure to low doses of benzene is unknown. Let-7e-5p pathway regulatory networks were constructed by bioinformatics analysis using a benzene-induced aplastic anemia (BIAA) mouse model. The MTT assay, EdU staining, flow cytometric analysis, dual luciferase reporter gene assay, and RIP assay were utilized to evaluate the effects of benzoquinone (1,4-BQ) on let-7e-5p pathway. This study consisted of 159 workers with a history of low-level benzene exposure and 159 workers with no history of benzene exposure. After the confounding factors were identified, the associations between let-7e-5p expression and hematotoxicity were assessed by multiple linear regression. Furthermore, we used four machine learning algorithms (decision trees, neural network, Bayesian network, and support vector machines) to construct a predictive model for detecting benzene-causing hematotoxicity in workers. In this study, compared with respective controls, let-7e-5p expression was decreased in BIAA mice and benzene-exposed workers. After 1,4-BQ exposure, let-7e-5p overexpression negatively regulated caspase-3 and p21 expression, protected cells from apoptosis, and facilitated cell proliferation. RIP assays, and dual luciferase reporter gene assays confirmed that let-7e-5p could target p21 and caspase-3 and regulate the cell cycle and apoptosis. The support vector machines classifier achieved the best prediction of benzene-induced hematotoxicity (prediction accuracy = 88.27, AUC = 0.83) by statistically characterizing the internal dose of benzene exposure and the oxidative stress index, as well as the expression levels of let-7e-5p pathway-related genes in benzene-exposed workers. Let-7e-5p may be a potential therapeutic target of benzene-induced hematotoxicity, provide a basis for evaluating the health hazards of long-term and low-dose benzene exposure in workers, and supply a reference for revising occupational health standards.

Effects of microsampling on toxicity assessment of hematotoxic compounds in a general toxicity study in rats

Microsampling (MS) has been increasingly used in toxicity studies reducing animal use for toxicokinetic analysis. However, especially for drugs with hematotoxic properties, the potential effects of MS on hematological parameters and subsequent toxicity assessment should be considered, while such properties are frequently unknown at the discovery stage. Here, we conducted a rat 2-week study of hematotoxic compounds and evaluated the effects of MS on toxicity assessment. Six-week-old female SD rats were orally dosed with vehicle, methylene blue trihydrate (MB: 300 mg/kg/day), or azathioprine (AZP: 12 and 24 mg/kg/day) for 2 weeks. Each treatment group was divided into non-MS and MS subgroups, and in the MS subgroups, 50 μL/time point of blood was collected from the jugular vein at 7 time points each on Days 1 and 13 of dosing. The test items included clinical signs, body weight, urinalysis, hematology, blood chemistry, necropsy, organ weight, and histopathology. In the MB non-MS subgroup, there were low values in red blood cell parameters, high values in reticulocytes and bilirubin, and increased extramedullary hematopoiesis, reflecting hemolytic anemia. In the AZP non-MS subgroup, there were low values of red and white blood cell parameters and decreased cellularity in the bone marrow, reflecting myelosuppression. The effects of MB and AZP were similarly observed in the MS subgroups, and the effects of MS on the toxicological endpoints were generally small. Based on these results, the effects of MS on toxicity assessment were considered to be small in rat toxicity studies even for hematotoxic compounds.

Biochemical and hematological effects of lead exposure in Iranian battery workers

OBJECTIVE

The purpose of our study was to evaluate the hematotoxic, hepatotoxic, and nephrotoxic responses following lead exposure among battery workers.

MATERIAL AND METHODS

Seventy-eight battery workers exposed to lead, and 78 non-exposed subjects were studied. Fasting blood samples were collected to assess kidney and liver function and hematological parameters. To determine the breathing zone and blood lead levels (BLLs), the samples were analyzed in accordance with the 7082 and 8003 NIOSH methods, respectively.

RESULTS

The battery workers had significantly higher breathing zone lead and BLLs than the non-exposed group. In battery workers, the most hematological parameters, including red blood cell, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, have significantly decreased. In contrast, white blood cell count has shown a significant increase as compared to the controls. The mean levels of alanine aminotransferase, aspartate aminotransferase as biomarker liver damage, and the serum levels of creatinine as a result of renal failure were significantly higher in the exposed group than in the non-exposed group.

CONCLUSIONS

These observations indicate that occupational exposure to lead exceeding its current threshold limit value (TLV) and biological exposure index (BEI) is associated with hematological symptoms and liver and kidney dysfunction.

LincRNA-p21 promotes p21-mediated cell cycle arrest in benzene-induced hematotoxicity by sponging miRNA-17-5p

Benzene is widely employed in manufacturing and causes hematotoxic effects and leukemia in humans. A long intergenic noncoding RNA (lincRNA)-microRNA (miRNA)-mRNA coexpression and competing endogenous RNA (ceRNA) regulatory network was constructed by bioinformatics analysis based on a benzene-induced aplastic anemia (BIAA) mouse model. In this population-based study, we observed a trend consistent with that in the BIAA mice: lincRNA-p21 and p21 were upregulated, while miRNA-17-5p expression was downregulated in benzene-exposed workers. Moreover, multiple linear regressions indicated that lincRNA-p21 was negatively associated with white blood cell (WBC) counts. Predictive thresholds of hematotoxicity were identified by ROC curve analysis with S-phenylmercapturic acid (SPMA) and lincRNA-p21 showing a better predictive ability than the other parameters and the combination of SPMA and lincRNA-p21 exhibiting the highest predictive value for hematotoxicity. LincRNA-p21 was predominantly present in the cytoplasm of bone marrow cells (BMCs) and K562 cells as assessed by fluorescence in situ hybridization (FISH). Upon exploring the underlying mechanism by which lincRNA-p21 mediates benzene-induced hematotoxicity, we observed that the negative regulation of 1,4-benzoquinone (1,4-BQ) on cell cycle arrest and inhibition of K562 cell proliferation was partially relieved by lincRNA-p21 knockdown, which can inhibit the expression of P21 and thereby suppress the toxic effects of 1,4-BQ. Finally, dual-luciferase reporter gene and RIP assay showed that, by acting as a sponge, lincRNA-p21 reduced the activity of miRNA-17-5p and consequently increased the expression of p21. In conclusion, our research suggested that benzene induces hematotoxicity via the lincRNA-p21/miRNA-17-5p/p21 signaling which might contribute to the underlying mechanism of lincRNA-p21 in benzene-induced hematotoxicity. Therefore, lincRNA-p21 can serve as a potential biomarker for the early detection of hematopoiesis inhibition in individuals with long-term exposure to low-dose benzene.

GCN5-mediated PKM2 acetylation participates in benzene-induced hematotoxicity through regulating glycolysis and inflammation via p-Stat3/IL17A axis

Benzene is a common environmental carcinogen that induces leukemia. Studies suggest that metabolic disorder has a relationship with the toxicity of benzene. Pyruvate kinase M2 (PKM2) is a key rate-limiting enzyme in glycolysis. However, the upstream and downstream regulatory mechanisms of PKM2 in benzene-induced hematotoxicity and the therapeutic effects of targeting PKM2 in vivo are unclear. This study aims to provide insights into the new mechanism of benzene-induced hematotoxicity and reveal the therapeutic significance of targeting PKM2. Herein, we demonstrated that PKM2-dependent glycolysis contributes to benzene-induced hematotoxicity by regulating inflammation reaction. Mechanistically, acetylated proteomics revealed that 1,4-benzoquinone (1,4-BQ) induced acetylation of PKM2 at position K66, and this modification contributed to the increase of PKM2 expression and can be inhibited by inhibition of acetyltransferase GCN5. Meanwhile, the elevated PKM2 was shown to prompt the activation of nuclear phosphorylated Stat3 (p-Stat3) and IL17A. Clinically, pharmacological inhibition of PKM2 alleviated the blood toxicity induced by benzene, which was mainly characterized by an increase in routine blood parameters and improvement of hematopoietic imbalance. Besides, elevated PKM2 is a promising biomarker in people occupationally exposed to benzene. Overall, we identified PKM2/p-Stat3/IL-17A axis participates in the hematotoxicity of benzene, and targeting PKM2 has certain therapeutic implications in hematologic diseases.

Nano-sized zeolite-like metal-organic frameworks induced hematological effects on red blood cell

Understanding the toxicity of metal-organic frameworks (MOFs) is important for improving their biocompatibility in further applications, especially the hematotoxicity of MOFs due to the unavoidable contact of MOFs with blood in biomedical science. Here we report the hematotoxicity and underlying mechanisms of nano-sized zeolite-like MOFs ZIF-8 and ZIF-67 because of their wide applications in biomedical science. ZIF-67 induced significant hemolysis of red blood cell (Rb) through breaking the structure of membrane due to the generation of free radicals, whereas ZIF-8 was hematocompatible. ZIF-67 was thus internalized by Rb and then bound with hemoglobin via hydrogen bond and van der Waals force, which influenced the structure and function of hemoglobin in accompany with heme release. These findings reveal the detailed mechanism of the hematological effects of MOFs on Rb and are helpful to the assessment of the toxicity and potential health risks of MOFs and the design of biosafe MOFs for biomedical applications.

Could Cisplatin Loading on Biosynthesized Silver Nanoparticles Improve Its Therapeutic Efficacy on Human Prostate Cancer Cell Line and Reduce Its In Vivo Nephrotoxic Effects?

Nanotechnology is a possible solution to the drawbacks of cancer therapy because it decreases the clinical side effects of chemotherapeutic drugs and increases their clinical activity. Thus, this work compared the in vitro cytotoxic activity and in vivo side effects of cisplatin (CP) with those of CP-loaded green silver nanoparticles (CP-AgNPs). The cytotoxic activity of CP, green AgNPs, and CP-AgNPs against PC-3, a human prostate cancer cell line, was assessed using MTT assay. CP-AgNPs had a superior cytotoxic effect on PC-3 cells with a 50% inhibition of viability (IC50) of 27.05 μg/mL, followed by CP with an IC50 of 57.64 μg/mL and AgNPs with an IC50 125.4 μg/mL. To evaluate in vivo side effects, 40 male adult Wistar rats were assigned into four groups and intraperitoneally injected with normal saline (control), CP (2.5 mg/kg body weight), green AgNPs (0.1 mL/kg body weight), and CP-AgNPs (2.5 mg/kg body weight). Intraperitoneal CP injection caused a substantial reduction in erythrocyte and leukocyte counts and hemoglobin concentration and a marked increase in urea and creatinine levels and disturbed the renal oxidant/antioxidant status. Furthermore, it caused noticeable structural alterations and significant upregulation of renal Bax and caspase-3 mRNA along with a significant downregulation of B-cell lymphoma 2 mRNA expressions. The loading of CP on green AgNPs significantly relieved the CP-induced pathological alterations and considerably enhanced its therapeutic effectiveness on PC-3 cells. These outcomes reflect the possible use of CP-AgNPs as a more efficient and safer anticancer agent than free CP.

The effects of glucose-6-phosphate dehydrogenase deficiency on benzene-induced hematotoxicity in mice

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme deficiency. Our previous study revealed the level of G6PD changed in wild type (WT) mice after benzene exposure. In this study, the pentose phosphate pathway (PPP) in regulation of benzene-induced hematotoxicity was investigated and other potential pathways were discovered in a G6PD deficiency mouse model. WT and G6PD mutation (G6PD^mut) mice were exposed to benzene (diluted in corn oil) at doses of 0 and 160 mg/kg by subcutaneous injection for 5 days/week, 4 weeks. Peripheral blood samples and bone marrow cells (BMCs) were obtained and measured. The levels of nicotinamide adenine dinucleotide phosphate (NADPH),reduced glutathione (GSH) and malondialdehyde (MDA) were detected and comet assay was analyzed for DNA damage in BMCs. Finally, RNA sequencing (RNA-seq) of BMCs was performed. The results showed that white blood cells decreased significantly in G6PD^mut mice compared with WT mice after benzene treatment. The ratio of hematopoietic stem/progenitor cells significantly decreased in G6PD^mut mice exposed to benzene. The reduction of NADPH and GSH revealed the effect on PPP with G6PD deficiency, which then caused the increase of MDA and DNA damage. Finally, RNA-seq results suggested potential genes including SHROOM4, CAMK2B and REN1 played potential roles of G6PD deficiency on benzene-induced hematotoxicity. Renin-angiotensin system and cAMP signaling pathway were potentially involved in the process. Our study provides a better understanding for the effects of G6PD deficiency on benzene-induced hematotoxicity.

NUDT15 is a key genetic factor for prediction of hematotoxicity in pediatric patients who received a standard low dosage regimen of 6-mercaptopurine

6-Mercaptopurine (6-MP) is commonly used for treatment of acute lymphoblastic leukemia (ALL). The incidence of hematotoxicity caused by this drug is quite high in Asians even using a standard low dosage regimen. The present study was aimed to elucidate the impact of thiopurine S-methyltransferase (TPMT), a nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15), inosine triphosphatase (ITPA) and ATP Binding Cassette Subfamily C Member 4 (ABCC4) polymorphisms on hematotoxicity in pediatric patients who received a standard low starting dose of 6-MP. One hundred and sixty-nine pediatric patients were enrolled and their genotypes were determined. Patients who carried NUDT15^∗3 and NUDT15^∗2 genotypes were at a 10-15 fold higher risk of severe neutropenia than those of the wild-type during the early months of the maintenance phase. Risk of neutropenia was not significantly increased in patients with other NUDT15 variants as well as in patients with TPMT, ITPA or ABCC4 variants. These results suggest that NUDT15 polymorphisms particularly, NUDT15^∗3 and NUDT15^∗2, play major roles in 6-MP-induced severe hematotoxicity even when using a standard low dosage of 6-MP and genotyping of these variants is necessary in order to obtain precise tolerance doses and avoid severe hematotoxicity in pediatric patients.

Heavy metals bioaccumulation and subsequent multiple biomarkers based appraisal of toxicity in the critically endangered Tor putitora

The construction of hydropower projects discharges effluents to aquatic bodies. The effluents consist of different chemicals including heavy metals. The current study assessed the effects of effluents discharged from an under-construction hydropower project on the bioaccumulation of heavy metals in the tissues of critically endangered Tor putitora (Hamilton, 1822) in the river Panjkora. The subsequent toxic impacts of higher bioaccumulation of heavy metals on different biochemical, hematological, and serum biochemical profiles were also studied. Different biochemical changes were observed in the tissues of T. putitora including stress biomarkers such as reactive oxygen species, lipid peroxidation, total protein contents, antioxidant enzymes (peroxidase, superoxide dismutase, catalase, reduced glutathione, glutathione reductase, and glutathione-s-transferase), acetylcholinesterase, and whole-body cortisol. The hematotoxic effects were also observed as the count of red blood cells, hematocrit, and hemoglobin decreased whereas the count of white blood cells increased. Serum biochemical analysis revealed that cholesterol, urea, total bilirubin, and glucose concentration increased, whereas total proteins and albumin decreased with an increase in the concentration of heavy metals across the sampling sites. The fish from the river was found to be under severe stress as compared to the fish from the reference site. To mitigate the current scenario, stocking fish in an appropriate amount is suggested. The fish diversity and water quality should be assessed at regular intervals to avoid further deterioration and diversity loss. The safety and conservation of wild fisheries should be ensured by implementing strict environmental protection and fishing laws.

Gender differences in hematotoxicity of benzene-exposed workers, three cross-sectional studies on 218,061 subjects

Our aim was to analyze the effects of benzene exposure on hematotoxicity in workers, with a focus on gender differences. The study was divided into three parts, and the survey included 218,061 workers. Since 2017, some workers are selected from the total workers each year to explore the possible influencing factors (age, duration of benzene exposure, TWA (8-h time-weighted average) of benzene, SPMA (S-phenylmercapturic acid), MDA (malondialdehyde), 8-OHdG (8-hydroxy-2'-deoxyguanosine) of different hematotoxicity of different genders). The abnormal rate of WBC (white blood cell), ANC (absolute neutrophil count), and platelets of female workers in the benzene exposure group was higher than that of males in the benzene exposure group and also higher than that of the female workers in the control group. Research results in 2019 showed increased SPMA as well as increases their DNA damage including 8-OHdG and MDA in benzene-exposed female workers compared to those in the control female group (all p < 0.05. SPMA, 8-OHdG, and MDA in benzene exposure female workers increased 555%, 183%, and 33.3%, respectively). Female workers are at significantly higher risk for blood system effects of benzene exposure. Therefore, more stringent standards and guidelines may be needed to protect the changing professional population, especially for females.

Glycine/glycine N-methyltransferase/sarcosine axis mediates benzene-induced hematotoxicity

Benzene, an important and widely used industrial chemical, is the cause of different types of blood disorders. However, the mechanisms of benzene-induced hematotoxicity are still unclear. This study aimed to explore the effects of benzene on metabolism, especially in amino acid metabolism, in human peripheral blood B lymphocyte cells (AHH-1 cells) treated with 1,4-benzoquinone (1,4-BQ) and in benzene-exposed population based on the un-targeted and targeted metabolomics platforms. The results showed that 1,4-BQ disturbed the metabolic activity, such as arginine biosynthesis, citrate cycle, glycine, serine, and threonine metabolism pathways, and significantly upregulated the ratio of sarcosine/glycine in vitro. Meanwhile, the targeted metabolomics further showed that the ratio of sarcosine/glycine was also increased in the benzene exposure population. Notably, the expression of glycine N-methyltransferase (GNMT), an enzyme catalyzing the transformation of glycine to sarcosine, was upregulated both in 1,4-BQ treated AHH-1 cells and benzene-exposed workers. These results imply that the glycine/GNMT/sarcosine axis was involved in benzene-induced hematotoxicity. Such evidence will help to develop a better understanding of the underlying mechanism of benzene-induced hematotoxicity at the level of amino acid metabolism.

Pyridoxine deficiency modulates benzene inhalation-induced hematotoxicity associated with hepatic CYP2E1 activity in B6C3F1 mice

•

Modifying effects of pyridoxine deficiency on benzene toxicity were assessed in B6C3F1 mice.

•

The mice were fed either a pyridoxine-deficient diet or control diet.

•

Pyridoxine deficiency was combined with nose-only benzene inhalation exposure (100 ppm).

•

Pyridoxine deficiency and benzene inhalation led to lower body, thymus and spleen weights.

•

The treatment combination also led to higher hepatic CYP2E1 protein expression and activity.

Pyridoxine is a co-factor in many enzymatic reactions and impacts of deficiency have been observed in affected populations. A possible modifying effect of pyridoxine deficiency on benzene toxicity was assessed in male B₆C₃F₁ mice fed either a pyridoxine-deficient diet or a control diet. This treatment was combined with benzene inhalation exposure (100 ppm) or no benzene treatment. Pyridoxine-deficient mice exposed to 100 ppm benzene had significantly lower body, thymus and spleen weights. While total white blood cell counts, percentage of lymphocytes, hematocrit and hemoglobin levels were lower, the percentage of neutrophils was significantly higher in deficient and benzene-exposed mice compared to non-exposed controls. Hepatic CYP2E1 protein expression and activity in the deficient and exposed mice were also significantly higher compared to the non-exposed controls. A significant correlation between CYP2E1 activity and several hematological parameters was observed. These results demonstrated that pyridoxine deficiency significantly impacted benzene-induced hematotoxicity. Moreover, the observed agonistic effect of pyridoxinedeficiency and benzene inhalation exposure on CYP2E1 would seem to indicate an involvement of metabolism, but this needs to be further assessed.

Hematological Consequences of Valproic Acid in Pediatric Patients: A Systematic Review with a Mechanistic Approach

PURPOSE

Although valproate (VPA) has several advantages in controlling seizures, it may cause serious hematological consequences. Hematotoxicity of VPA is particularly important in pediatrics because patients at this age are at a growing risk of leukemia. For a conclusive agreement about the toxicity of VPA, in this study, we systematically reviewed the literature in which the hematological consequences of VPA had been emphasized. <P> Methods: A systematic literature search was performed in June 2021 on electronic databases to find original research on the association between VPA therapy and hematotoxicity in pediatric patients. For this purpose, the following search terms "hematotoxicity", "valproic acid" and "pediatrics" with different spellings and similar terms, were searched in the title, keywords, and abstracts of articles. The data were collected and used for qualitative data description. <P> Results: A total of 36 relevant articles with an overall 1381 study population were included. The results showed that VPA could cause severe hematotoxicity in children even at therapeutic doses. Neutropenia, thrombocytopenia, and bone marrow depression are the most common complications associated with VPA therapy. Also, findings showed that after discontinuation of VPA and starting other antiepileptic drugs or reducing the administered VPA dose, hematologic damages were entirely resolved, and all the hematological parameters improved during two weeks. <P> Conclusions: This review showed that VPA therapy could cause hematotoxicity in children; hence, it is recommended to monitor hematological indices during VPA therapy. Also, according to the suggested mechanistic pathways of VPA side effects, a combination of VPA with antioxidants may reduce hematological side effects.

Quercetin attenuated the Benzene-induced hemato- and hepatotoxicity in mice

The protective effects of Quercetin (QCN) on Benzene (BNZ)-induced hemato- and hepatotoxicy were investigated. To reach this goal, 36 adult male mice were divided into 6 groups (n = 6). The control group was not exposed to BNZ, while animals in BNZ group were exposed to BNZ (30 ppm) and the animals of QCN group were received QCN (50 mg/kg, orally), the fourth, fifth and sixth groups were exposed to 30 ppm BNZ and received 10, 50 and 100 mg/kg QCN one h before the BNZ exposure, for 28 days. The day after the last exposure following anesthesia and the blood collection, the liver and femur tissues were collected. The bone marrow samples were extracted and subjected to micronucleus assay. The blood samples were processed for hematological and biochemical analyses. Histopathological examinations were performed on the liver samples. QCN reduced significantly (p < 0.05) the BNZ-elevated hepatic enzymes and ameliorated the BNZ-induced WBC and RBC reduction. The BNZ-elevated micronucleus percentage both in the bone marrow and peripheral blood was remarkably declined in the QCN-received groups. QCN improved the BNZ-induced histopathological changes and oxidative status in the liver and serum. Our results suggest that QCN could be a protective supplement to reduce the BNZ-induced hemato- and hepatotoxicities.

A retrospective analysis

INTRODUCTION

Nephro- and hematotoxicity after peptide receptor radionuclide therapy (PRRT) have been described in multiple studies with heterogeneous cumulative activities, number of cycles or radiolabelled peptides. Though highly differentiated metastasized neuroendocrine tumours (NET) have long progression free survival, they may progress. We analysed long-term side effects in a homogenous treatment schedule in PRRT-patients and their impact on future oncologic treatment in case of progression.

METHODS

From our database 89/384 patients receiving the same PRRT (Lu-177-DOTATATE or Y-90-DOTATOC) 4 times every 10 to 12 weeks and a follow-up at 12 months were analysed. One patient had three and 11 patients had two times four PRRT-cycles resulting in 102 cases. eGFR, Hb, WBC and platelets before the first and one year after the fourth therapy cycle were compared. eGFR-Grading was done according to chronic kidney disease classification (CKD) and grading of hematotoxicity according to Common Terminology Criteria for Adverse Events (CTCAE). Impact of age, gender, cumulative activity, type of PRRT on long-term-toxicity was also assessed.

RESULTS

eGFR grade 1-2 dropped from 87/102 at the baseline to 71 cases at follow-up (p<0.001). Before treatment grade 3a was found in 13, grade 3b in 2 cases, and at follow-up grade 3a in 25, grade 3b in 5, and grade 4 in 1 case. Anaemia prior to PRRT and at follow-up was grade 0 in 63 versus 48 (p<0.001), grade 1 in 36 versus 48, and grade 2 in three versus six cases. In white blood cell count and platelets, there were no significant changes in grading occurring. Subgroup analysis revealed that only in the age group 65 and older was there a higher incidence for anaemia (p=0.006). CONCLUSIóN: In roughly 20% of cases an increase in grading of nephro- or hematotoxicity is observed. In those patients, except in one, toxicity findings were mild or moderate one year after completion of four cycles of PRRT with either Y-90- or Lu-177-SST-analogues. In terms of safety, PRRT has no critical impact on further oncologic treatment options in the case of disease progression.

Kefir milk alleviates benzene-induced immunotoxicity and hematotoxicity in rats

The adverse health effects of benzene occupational and circumstance pollution exposure are an increasing concern. It leads to damage to various human tissues including bone marrow and ovarian tissues and many vital physiological processes. Previous studies showed that kefir is a rich probiotic, having protective effect, thanks to its antioxidant, anti-inflammatory, and immunomodulatory capacity. The purpose of this study was to evaluate the potential efficacy of kefir to remediate benzene toxicity in rat. Thirty-two female rats were randomly allocated and administered orally with benzene and/or kefir during a period of 21 consecutive days. At the end of the experiment, hematological and bone marrow cell changes were estimated. The animals exposed to benzene exhibited anemia and a significant decrease in the levels of white blood cell. Moreover, benzene led to the activation of gene expression of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-6 (IL-6), a myelotoxicity in bone marrow cells. Our data showed that kefir treatment alleviated benzene-associated weight loss and increased the number of whole blood cells in peripheral blood and nucleated cells in the bone marrow. Furthermore, these physiological results were observed with animals showing high concentrations of lactic acid bacteria (LAB) determined from fecal samples, which are considered an indicator of kefir-associated microorganisms. Our study suggests that kefir is a potential nutritional supplement target to attenuate hematotoxicity induced by benzene.

Hematologic safety of 177Lu-PSMA-617 radioligand therapy in patients with metastatic castration-resistant prostate cancer

BACKGROUND

Myelosuppression is a potential dose-limiting factor in radioligand therapy (RLT). This study aims to investigate occurrence, severity and reversibility of hematotoxic adverse events in patients undergoing RLT with ¹⁷⁷Lu-PSMA-617 for metastatic castration-resistant prostate cancer (mCRPC). The contribution of pretreatment risk factors and cumulative treatment activity is taken into account specifically.

METHODS

RLT was performed in 140 patients receiving a total of 497 cycles. A mean activity of 6.9 [Formula: see text] 1.3 GBq ¹⁷⁷Lu-PSMA-617 per cycle was administered, and mean cumulative activity was 24.6 [Formula: see text] 15.9 GBq. Hematological parameters were measured at baseline, prior to each treatment course, 2 to 4 weeks thereafter and throughout follow-up. Toxicity was graded based on Common Terminology Criteria for Adverse Events v5.0.

RESULTS

Significant (grade ≥ 3) hematologic adverse events occurred in 13 (9.3%) patients, with anemia in 10 (7.1%), leukopenia in 5 (3.6%) and thrombocytopenia in 6 (4.3%). Hematotoxicity was reversible to grade ≤ 2 through a median follow-up of 8 (IQR 9) months in all but two patients who died from disease progression within less than 3 months after RLT. Myelosuppression was significantly more frequent in patients with pre-existing grade 2 cytopenia (OR: 3.50, 95%CI 1.08-11.32, p = 0.04) or high bone tumor burden (disseminated or diffuse based on PROMISE miTNM, OR: 5.08, 95%CI 1.08-23.86, p = 0.04). Previous taxane-based chemotherapy was associated with an increased incidence of significant hematotoxicity (OR: 4.62, 95%CI 1.23-17.28, p = 0.02), while treatment with ²²³Ra-dichloride, cumulative RLT treatment activity and activity per cycle were not significantly correlated (p = 0.93, 0.33, 0.29).

CONCLUSION

Hematologic adverse events after RLT have an acceptable overall incidence and are frequently reversible. High bone tumor burden, previous taxane-based chemotherapy and pretreatment grade 2 cytopenia may be considered as risk factors for developing clinically relevant myelosuppression, whereas cumulative RLT activity and previous ²²³Ra-dichloride treatment show no significant contribution to incidence rates.

Comparison of pretherapeutic osseous tumor volume and standard hematology for prediction of hematotoxicity after PSMA-targeted radioligand therapy

Purpose

Hematotoxicity is a potentially dose-limiting adverse event in patients with metastasized castration-resistant prostate cancer (mCRPC) undergoing prostate-specific membrane antigen (PSMA)-directed radioligand therapy (RLT). We aimed to identify clinical or PSMA-targeted imaging-derived parameters to predict hematological adverse events at early and late stages in the treatment course.

Methods

In 67 patients with mCRPC scheduled for ¹⁷⁷Lu-PSMA-617 RLT, pretherapeutic osseous tumor volume (TV) from ⁶⁸Ga-PSMA-11 PET/CT and laboratory values were assessed. We then tested the predictive capability of these parameters for early and late hematotoxicity (according to CTCAE vers. 5.0) after one cycle of RLT and in a subgroup of 32/67 (47.8%) patients after four cycles of RLT.

Results

After one cycle, 10/67 (14.9%) patients developed leukocytopenia (lymphocytopenia, 39/67 [58.2%]; thrombocytopenia, 17/67 [25.4%]). A cut-off of 5.6 × 10³/mm³ for baseline leukocytes was defined by receiver operating characteristics (ROC) and separated between patients with and without leukocytopenia (P < 0.001). Baseline leukocyte count emerged as a stronger predictive factor in multivariate analysis (hazard ratio [HR], 33.94, P = 0.001) relative to osseous TV (HR, 14.24, P = 0.01). After four cycles, 4/32 (12.5%) developed leukocytopenia and the pretherapeutic leukocyte cut-off (HR, 9.97, P = 0.082) tended to predict leukocytopenia better than TV (HR, 8.37, P = 0.109). In addition, a cut-off of 1.33 × 10³/mm³ for baseline lymphocytes separated between patients with and without lymphocytopenia (P < 0.001), which was corroborated in multivariate analysis (HR, 21.39, P < 0.001 vs. TV, HR, 4.57, P = 0.03). After four cycles, 19/32 (59.4%) developed lymphocytopenia and the pretherapeutic cut-off for lymphocytes (HR, 46.76, P = 0.007) also demonstrated superior predictive performance for late lymphocytopenia (TV, HR, 5.15, P = 0.167). Moreover, a cut-off of 206 × 10³/mm³ for baseline platelets separated between patients with and without thrombocytopenia (P < 0.001) and also demonstrated superior predictive capability in multivariate analysis (HR, 115.02, P < 0.001 vs.TV, HR, 12.75, P = 0.025). After four cycles, 9/32 (28.1%) developed thrombocytopenia and the pretherapeutic cut-off for platelets (HR, 5.44, P = 0.048) was also superior for the occurrence of late thrombocytopenia (TV, HR, 1.44, P = 0.7).

Conclusions

Pretherapeutic leukocyte, lymphocyte, and platelet levels themselves are strong predictors for early and late hematotoxicity under PSMA-directed RLT, and are better suited than PET-based osseous TV for this purpose.

Severe Candida glabrata pancolitis and fatal Aspergillus fumigatus pulmonary infection in the setting of bone marrow aplasia after CD19-directed CAR T-cell therapy - a case report

Background

Prolonged myelosuppression following CD19-directed CAR T-cell transfusion represents an important, yet underreported, adverse event. The resulting neutropenia and multifactorial immunosuppression can facilitate severe infectious complications.

Case presentation

We describe the clinical course of a 59-year-old patient with relapsed/refractory DLBCL who received Axicabtagene-Ciloleucel (Axi-cel). The patient developed ASTCT grade I CRS and grade IV ICANS, necessitating admission to the neurological ICU and prolonged application of high-dose corticosteroids and other immunosuppressive agents. Importantly, neutropenia was profound (ANC < 100/μl), G-CSF-refractory, and prolonged, lasting more than 50 days. The patient developed severe septic shock 3 weeks after CAR transfusion while receiving anti-fungal prophylaxis with micafungin. His clinical status stabilized with broad anti-infective treatment and intensive supportive measures. An autologous stem cell backup was employed on day 46 to support hematopoietic recovery. Although the counts of the patient eventually started to recover, he developed an invasive pulmonary aspergillosis, which ultimately lead to respiratory failure and death. Postmortem examination revealed signs of Candida glabrata pancolitis.

Conclusions

This case highlights the increased risk for fatal infectious complications in patients who present with profound and prolonged cytopenia after CAR T-cell therapy. We describe a rare case of C. glabrata pancolitis associated with multifactorial immunosuppression. Although our patient succumbed to a fatal fungal infection, autologous stem cell boost was able to spur hematopoiesis and may represent an important therapeutic strategy for DLBCL patients with CAR T-cell associated bone marrow aplasia who have underwent prior stem cell harvest.

Key event-informed risk models for benzene-induced acute myeloid leukaemia

Occupational exposure to benzene at levels of 10 ppm or more has been associated with increased risk of acute myeloid leukaemia (AML). The mode of action (MOA) for AML development leading to mortality is anticipated to include multiple earlier key events, which can be observed in hematotoxicity and genetic toxicity in peripheral blood of exposed workers. Prevention of these early events would lead to prevention of the apical, adverse outcomes, the morbidity and mortality caused by the myelodysplastic syndromes (MDS) and AML. Incorporation of key event information should modify the risk model, but few modification approaches have been suggested. To that end, two approaches to risk model modification are described that use sub-linear and segmented linear increases in risk below key events, while maintaining a linear increase in AML mortality risk beginning at 2 ppm, the lowest observed adverse effect concentration (LOAEC) identified for hemato- and geno- toxicity in high quality studies of human occupational exposure. Below 2 ppm two different modification approaches to quantitative risk models were applied: a continuously decreasing slope model and a segmented modification in slope. These two approaches provide greater flexibility to incorporate MOA information in risk model development and selection.

Ethephon causes reproductive malfunction in adult male mice: Histological and biochemical evidence

Ethephon (C₂H₆ClO₃P; ETP), an organophosphorus pesticide regulating plant growth, is widely used for early ripening of fruits and vegetables in agriculture. The aim of this study was to investigate the effects of ETP on histomorphometrical and biochemical parameters in mouse testicular tissue. In this study, 90 adult male mice were randomly divided into six equal groups (n = 15). The ETP was administered orally at different doses (120, 240 and 480 mg kg^-1) daily for 35 days. Untreated control, sham (received only normal saline) and neostigmine bromide-treated (positive control; 0.10 mg kg^-1 orally; once per week) groups were also considered. Following 35 days, animals were euthanized and testicle and serum samples were taken. Accordingly, blood and serum acetylcholinesterase (AChE), catalase, total antioxidant capacity (TAC) and malondialdehyde (MDA) levels as well as histomorphometrical changes of testicles were investigated. The ETP-administered animals represented a significant reduction in AChE, TAC and catalase levels and remarkable increment in MDA content. A marked reduction was also seen in the germinal epithelium height, connective tissue thickness, seminiferous tubules diameter and Leydig cell number as well as spermiogenesis and Sertoli cell indices in ETP-treated mice compared to control ones. Similar findings were found in neostigmine bromide-treated animals. In conclusion, the ETP significantly affects the serum and blood anti-oxidant statuses and results in severe histological damages both at germ and somatic cell levels, suggesting its hematotoxic and reprotoxic characteristic.

Association between benzene exposure, serum levels of cytokines and hematological measures in Chinese workers: A cross-sectional study

BACKGROUND

Low benzene exposure leads to hematotoxicity, but we still lack sensitive early monitoring and early warning markers. Benzene is associated with inflammation, which is mainly mediated by cytokines network. However, until now few studies have conducted high-throughput detection of multi-cytokines to get a global view of cytokine changes and screen for markers of benzene-induced toxicity. We hypothesized that cytokine profiles mediate benzene-induced hematotoxicity.

METHODS

228 subjects consisting of 114 low benzene exposed workers and 114 healthy controls were recruited at Research Center of Occupational Medicine, Peking University Third Hospital, Beijing. The serum concentrations of 27 cytokines were detected by cytokinomics array, urinary benzene series metabolites were measured by UPLC-MS/MS, and peripheral blood cell counts were observed by basic blood test.

RESULTS

Among 27 cytokines, IL-9 and MIP1-α were significantly lower, but IL-4, IL-10, IL-15, MCP-1, TNF-α and VEGF were significantly higher in benzene exposure group than controls. Urinary benzene metabolite S-phenylmercapturic acid (S-PMA) was significantly higher in benzene exposure group and had a negative linear relationship with WBC count. S-PMA was only significantly associated with IL-9, meanwhile IL-9, IL-15 and VEGF had a positive linear relationship with WBC count. The bootstrapping mediation models showed that the effect of S-PMA on WBC count was partially explained by IL-9 for 10.11%.

CONCLUSION

This study suggests that exposure to benzene was associated with alternation of blood cell count and cytokine profiles in workers exposed to low levels of benzene, especially decreases of WBC count and IL-9. We also found IL-9 partially mediated the effect of low benzene exposure on WBC count, which may be a potential and promising early monitoring and early warning marker of benzene hematotoxicity.

Famciclovir leads to failure of hematopoiesis, but may have the benefit of relieving myeloid expansion in MDS-like zebrafish

Famciclovir (FCV) is an antiviral drug that is often utilized after bone marrow transplantation to prevent viral infection. Yet, its role in hematopoiesis is poorly understood. Here, by utilizing a zebrafish model, we found that FCV exposure led to hematopoietic failure by impairing the proliferation of hematopoietic stem and progenitor cell (HSPC) and inducing HSPC apoptosis. On the other hand, FCV treatment could effectively relieve myeloid malignancies in the c-myb^hyper MDS-like fish model, and played a role not only in the embryonic stage but also in adult zebrafish. This study reveals that FCV functions as a double-edged sword, with hematotoxicity at a high level, but that appropriate FCV treatment may be beneficial for the treatment of MDS.

Derivation of an occupational exposure limit for benzene using epidemiological study quality assessment tools

This paper derives an occupational exposure limit for benzene using quality assessed data. Seventy-seven genotoxicity and 36 haematotoxicity studies in workers were scored for study quality with an adapted tool based on that of Vlaanderen et al., 2008 (Environ Health. Perspect. 116 1700-5). These endpoints were selected as they are the most sensitive and relevant to the proposed mode of action (MOA) and protecting against these will protect against benzene carcinogenicity. Lowest and No- Adverse Effect Concentrations (LOAECs and NOAECs) were derived from the highest quality studies (i.e. those ranked in the top tertile or top half) and further assessed as being "more certain" or "less certain". Several sensitivity analyses were conducted to assess whether alternative "high quality" constructs affected conclusions. The lowest haematotoxicity LOAECs showed effects near 2 ppm (8 h TWA), and no effects at 0.59 ppm. For genotoxicity, studies also showed effects near 2 ppm and showed no effects at about 0.69 ppm. Several sensitivity analyses supported these observations. These data define a benzene LOAEC of 2 ppm (8 h TWA) and a NOAEC of 0.5 ppm (8 h TWA). Allowing for possible subclinical effects in bone marrow not apparent in studies of peripheral blood endpoints, an OEL of 0.25 ppm (8 h TWA) is proposed.

Dataset on the effect of Benzene exposure on genetic damage, hematotoxicity, telomere length and polymorphisms in metabolic and DNA repair genes

In this paper, we present an occupational dataset to evaluate benzene exposure on the effective biomarkers of genetic damage, indicated as cytokinesis-block micronucleus (MN) frequency, hematotoxicity, indicated as white blood cells (WBC) counts, and molecular marker of telomere length (TL). And we further to eliminate the mechanism of benzene induced damage. Then evaluate the effects of sites polymorphism in environmental response genes, including 18 sites in metabolic and DNA repair genes, and the interaction between gene polymorphism and benzene exposure. This dataset is supplementary to the submitted research by [1] focused on the biomarkers TL, and a detailed description of the subjects sampling, biomarkers detection, data analysis and discussion are discussed in detail.

Benzene exposure induces gut microbiota dysbiosis and metabolic disorder in mice

The gut microbiota comprises a multispecies microbial community and is essential for maintaining health. Benzene is a widespread environmental and occupational pollutant that mainly causes blood and bone marrow abnormalities. However, the effects of benzene on gut microbiota and metabolism have not yet been investigated. In this study, C57BL/6 mice were exposed to 0, 6, 30 and 150 mg/kg benzene by subcutaneous injection for 30 days. We observed that white blood cell levels significantly decreased in the three benzene exposure groups, while red blood cell and hemoglobin levels were only changed remarkably in 30 and 150 mg/kg benzene-treated mice. The results of 16S rRNA sequencing showed that benzene exposure altered the overall structure of the gut microbial communities. In addition, significant enrichments of Actinobacteria (p < .05) at the phylum level and Helicobacter at the genus level were observed in the cecal contents and feces of mice exposed to 150 mg/kg benzene. Moreover, there was a significant negative correlation between Actinobacteria abundance and basic blood indicators, including white blood cell, red blood cell, and hemoglobin levels. Furthermore, according to LC-MS analysis, a total of 42 cecal metabolites were significantly altered by 150 mg/kg benzene. Several metabolic pathways were significantly influenced by benzene exposure, including cysteine and methionine metabolism, porphyrin and chlorophyll metabolism, steroid biosynthesis, aminoacyl-tRNA biosynthesis, and arginine and proline metabolism. In summary, this study demonstrated that benzene exposure causes dysbiosis of the gut microbiota and metabolic disorder in mice.

An observational single-center study of nivolumab in Indian patients with recurrent advanced non-small cell lung cancer

Purpose

Limited treatment options are available for patients with advanced non-small cell lung cancer (NSCLC) after failure of first-line platinum-based chemotherapy. The treatment of recurrent advanced NSCLC progressed with the arrival of nivolumab and other immunotherapeutic agents. Our single-center prospective study aimed to present the effectiveness and safety of nivolumab in second-line setting after first-line platinum doublet in Indian patients with advanced NSCLC.

Patients and Methods

Twenty-nine adult patients with stage IV NSCLC treated with nivolumab after failure of first-line platinum-based chemotherapy at Bhagwan Mahaveer Cancer Hospital and Research Centre, Jaipur, India, between October 2016 and January 2018, were included in the study. Overall survival (OS), hematological, and nonhematological toxicities were evaluated.

Results

A total of 29 patients (mean age of 59.6 years at enrollment) were evaluated. Histological evaluation revealed adenocarcinoma (44.8%) and squamous (55.2%) type of cancer. The Eastern Cooperative Oncology Group performance score was II in 7 patients (24.1%) and I in 22 (75.9%) patients. Patients received an average of four cycles of nivolumab. The median survival duration was 101 days, and OS rate in the study was 51.7%. Six patients (20.7%) had stable disease response, five patients (17.2%) had partial response, and three patients (10.3%) were lost to follow-up. Asthenia and cough were the most common nonhematological toxicities. Only three patients developed hematological toxicities (anemia and thrombocytopenia).

Conclusion

Data from our study suggest nivolumab is well-tolerated and effective in Indian patients with recurrent advanced NSCLC after failure of the multiple first lines of platinum-based combination chemotherapy.

lncRNAVNN3 mediated benzene-induced hematotoxicity through promoting autophagy and apoptosis

The potential toxicity of low-dose benzene exposure to human health has received attention, but the mechanisms of low-dose benzene-induced hematotoxicity remain largely unknown. The purpose of our study was to investigate the relationships between lncRNAVNN3 expression with benzene-induced autophagy and apoptosis in control and benzene-exposed workers. Seventy benzene-exposed workers and seventy non-benzene-exposed healthy workers were recruited. The expression of lncRNAVNN3, serum autophagy-associated and apoptosis-associated proteins were evaluated, and the relationship among them were also analysed. Furthermore, the mechanism of lncRNAVNN3 on autophagy and apoptosis induced by benzene metabolite (1, 4-benzoquinone, 1, 4-BQ) was investigated in vitro. The results showed that the expression of lncRNAVNN3 increased in benzene-exposed workers (p < 0.05). A positive correlation was found between lncRNAVNN3, serum autophagy-associated and apoptosis-associated proteins. In addition, we found that the knockdown of lncRNAVNN3 reduced phosphorylation of beclin1 and Bcl-2, which mediated 1, 4-benzoquinone-induced autophagy and apoptosis. Overall, lncRNAVNN3 mediated 1, 4-benzoquinone-induced autophagy and apoptosis though regulating phosphorylation of beclin1 and Bcl-2, suggesting that lncRNAVNN3 might be a novel early sensitive biomarker of benzene-induced hematotoxicity.

Benzene metabolites trigger pyroptosis and contribute to haematotoxicity via TET2 directly regulating the Aim2/Casp1 pathway

Background

Long term low-dose benzene exposure leads to the inhibition of haematopoiesis. However, the underlying mechanisms remained poorly defined, especially mediated by early effector molecules.

Methods

Here, we first found in mRNA microarray that pyroptotic classic genes (Casp1, 4, 5, and IL1β) were up-regulated and represented dose-dependent differential expression in controls, low-dose benzene-exposed and chronic benzene-poisoned workers, and the expression of Casp1 and IL1β were confirmed in low-dose benzene-exposed workers and was accompanied with elevated potent proinflammatory IL1β. In vitro studies showed that benzene metabolites induced AHH-1 cell pyroptosis through activating Aim2/Casp1 pathway with the increased expression of GSDMD. Meanwhile, TET2 overexpression was elevated in vivo and in vitro and it was positively correlated with IL1β. Further, we verified that pyroptosis caused by 1,4-BQ could be ameliorated in vitro by RNAi or pretreatment with Dimethyloxalylglycine (DMOG), the inhibitor of TET2.

Findings

Exposure to benzene can trigger pyroptosis via TET2 directly regulating the Aim2/Casp1 signaling pathway to cause haematotoxicity.

Interpretation

Benzene metabolites induced pyroptotic cell death through activation of the Aim2/Casp1 pathway which can be regulated by Tet2 overexpression. Tet2 may be a potential risk factor and is implicated in the development of benzene-related diseases.

Fund

National Natural Science Foundation of China; the Support Project of High–level Teachers in Beijing Municipal Universities in the Period of 13th Five–year Plan; Beijing Natural Science Foundation Program and Scientific Research Key Program of Beijing Municipal Commission of Education.

Current development in integrative therapy of traditional Chinese medicine for cancer treatment: A mini-review

Cancer is a major public health problem worldwide, and there has been a sustained rise in its incidence in both developing and developed countries. Although there are currently numerous effective therapeutic options for cancer, they sometimes exhibit resistance and obvious side effects. Traditional Chinese medicine (TCM) currently plays a major role in cancer therapy by downregulating the growth of cancer cells through various pathways and by relieving side effects. Studies in cultured human malignant cell lines have demonstrated that Solanum nigrum can control cancer cell proliferation and cancer progression by inducing autophagic and apoptotic cell death. Case–control studies have indicated that TCM can relieve the side effects of cancer therapy. This review provides brief insights into the anticancer effects of TCM, the side effects relieved by TCM, and the role of TCM doctors in cancer treatment.

•

Aqueous extracts of Solanum nigrum can control cancer cell proliferation and cancer progression by inducing autophagic and apoptotic cell death.

•

TCM can relieve side effects such as hematotoxicity, hepatotoxicity, and paronychia caused by conventional anticancer treatments.

•

A TCM doctor consulting and referral system for patients with cancer should be established.

Preliminary results of toxicity studies in rats following low-dose and short-term exposure to methyl mercaptan

The present study was carried out to evaluate the hematotoxicity and respiratory toxicity of methyl mercaptan in Sprague-Dawley rats. A dynamic exposure methodology was adopted in this study following 7 days of exposure by repeated inhalation. The concentration of methyl mercaptan used in the exposure was 0.5 ppm and the exposure time was 6 h/day for 7 days. After exposure, the rats were sacrificed to collect lung tissue and blood samples. Routine blood and serum biochemistry were conducted. Morphological injury of lung tissue was detected by hematoxylin and eosin staining. Decreased food consumption and body weight gain in both sexes were noted in the exposure group compared with the control group. Several significant changes in hematological parameters were observed. The results showed that the blood urea nitrogen (UREA) levels and superoxide dismutase (SOD) values were significantly decreased in exposed male rats. Malondialdehyde (MDA) in lung tissue was significantly increased in both males and females in the exposed group. In the histopathological examination of lung tissue, terminal bronchiole constriction, alveolar congestion, and erythrocyte exudation were observed, suggesting that the lungs may be target organs after inhaling methyl mercaptan and workers exposed to this concentration may cause some pulmonary stimulation and injury.

Venetoclax with azacitidine targets refractory MDS but spares healthy hematopoiesis at tailored dose

Patients with Myelodysplastic Syndromes (MDS) and secondary Acute Myeloid Leukemia (sAML) have a very poor prognosis after failure of hypomethylating agents (HMA). Stem cell transplantation is the only effective salvage therapy, for which only a limited number of patients are eligible due to age and comorbidity. Combination therapy of venetoclax and azacitidine (5-AZA) seems to be a promising approach in myeloid malignancies, but data from patients with HMA failure are lacking. Furthermore, a considerable concern of combination regimens in elderly AML and MDS patients is the toxicity on the remaining healthy hematopoiesis. Here, we report in vitro data showing the impact of venetoclax and 5-AZA, alone or in combination, in a larger cohort of MDS/sAML patients (n = 21), even after HMA failure (n = 13). We especially focused on the effects on healthy hematopoiesis and the impact on colony forming capacity as a parameter for long-term effects. To the best of our knowledge, we show for the first time that venetoclax in combination with capped dose of 5-AZA targets cell malignancies, while sparing healthy hematopoiesis.

Establishment of a zebrafish hematological disease model induced by 1,4-benzoquinone

Benzene exposure is associated with various hematological disorders, in particular leukemia. The reactive metabolite of benzene, 1,4-benzoquinone (BQ), generated in bone marrow, is suggested to be a key molecule in mediating benzene-induced hematotoxicity and carcinogenicity. However, its pathogenic role remains largely unknown due to a lack of suitable vertebrate whole-organism models. Here, we present an in vivo study to reveal the effect of BQ exposure on hematotoxicity in zebrafish. From embryonic stages to adulthood, BQ exposure suppressed erythroid and lymphoid hematopoiesis but led to abnormal accumulation of myeloid cells and precursors, which resembles benzene-induced cytopenia and myeloid dysplasia in humans. This myeloid expansion is caused by granulocyte, but not macrophage, lineage, emphasizing the significant role of lineage specificity in BQ-mediated hematopoietic toxicity. Analysis of the c-myb (also known as myb)-deficient mutant cmyb^hkz3 revealed that BQ induced neutrophilia in a c-myb-dependent manner, demonstrating that c-myb is a key intrinsic mediator of BQ hematotoxicity. Our study reveals that BQ causes lineage-specific hematotoxicity in zebrafish from embryonic stages to adulthood. Since c-myb is indispensable for BQ to induce neutrophilia, c-myb could serve as a potential drug target for reversing BQ hematotoxicity.

Summary: Acute exposure to 1,4-benzoquinone leads to lineage-specific hematotoxicity in zebrafish from embryonic stages to adulthood, resembling benzene-induced cytopenia and myeloid dysplasia in humans.

Borax Supplementation Alleviates Hematotoxicity and DNA Damage in Rainbow Trout (Oncorhynchus mykiss) Exposed to Copper

Heavy metals have harmful effects on health of both ecosystems and organisms to their accumulation ability. Copper (Cu) is an essential element for organism survival, but EPA considers Cu as a priority pollutant. On the other hand, boron has well-defined biological effects in living organisms including cytoprotection and genoprotection, although borax (BX) metabolism is poorly described in fish. Moreover, the effects of boron supplementation against Cu-induced hematotoxicity and DNA damage in aquatic organisms are still undetermined. Therefore, the main aim of this study was to provide an overview of the strategy for therapeutic potential of BX against Cu exposure in rainbow trout, Oncorhynchus mykiss. For this aim, fish were fed with different doses of BX and/or copper (1.25, 2.5, and 5 mg/kg of BX; 500 and 1000 mg/kg of Cu) for 21 days in pretreatment and combined treatment options. At the end of the treatments (pre and combined), the hematological index (total erythrocytes count (RBC), total leucocytes count (WBC), hemoglobin (Hb), hematocrit (Hct), total platelet count (PLT), mean cell hemoglobin concentration (MCHC), mean cell hemoglobin (MCH), mean cell volume (MCV)), oxidative DNA damage (8-hydroxy-2-deoxyguanosine (8-OHdG)), and nuclear abnormalities in blood samples of treated and untreated fish were investigated. The statistically significant (p < 0.05) and dose-dependent increases in hematological indices, 8-OH-dG level, and rates of nuclear abnormalities were observed after exposure to Cu in both treatment group fish as compared to untreated group. On the contrary, treatments with BX doses alone did not alter these hematological and DNA damage endpoints. Moreover, both pretreatment and combined treatments with BX significantly alleviated Cu-induced hematotoxicity and genotoxicity. In a conclusion, the obtained data firstly revealed that borax exhibited hematoprotective and genoprotective effects against copper-induced toxicity in fish.

Plasma metabonomics investigation reveals involvement of fatty acid oxidation in hematotoxicity in Chinese benzene-exposed workers with low white blood cell count

Benzene is an environmental and occupational contaminant. Health hazards associated with occupational benzene exposure is a major public health problem in China. In this study, we analyzed metabolite profiles among plasma samples collected from benzene-exposed workers with low white blood cell count (BLWs) and healthy controls using high-performance liquid chromatography-time-of-flight mass spectrometry. To screen potential benzene hematotoxicity biomarkers and metabolic pathways, principal component analysis was used to examine metabolite profile changes in plasma samples. The alterations in fatty acid oxidation (FAO) pathway were consistent with our previous findings in a mouse model; hence, two key genes were selected and verified in WBC samples. A total of nine identified metabolites were significantly changed in BLWs, which were involved in glutathione metabolism, porphyrin metabolism, lipid metabolism pathway, and FAO metabolism. Furthermore, compared with healthy controls, the mRNA expressions of carnitine acyltransferase (CRAT) and ACADVL were significantly increased in BLWs. Particularly, WBC counts was negatively correlated with the expression of AVADVL in BLWs. These aberrant metabolites could act as potential biomarkers for benzene hematotoxicity. In addition, fatty acid oxidation pathway may play a critical role in the development of hematotoxicity caused by benzene.

Functional Assays of Hematopoietic Stem Cells in Toxicology Research

The hematopoietic stem cell is the foundational cell of the entire blood and immune system and as such is particularly sensitive to toxicological insults. While this review will identify some of the classes of chemicals known to be hematotoxic, most of the discussion will focus on the strengths and weaknesses of various hematological assays used in toxicology research. Furthermore, protocols for isolating both human and murine hematopoietic stem cells are described. Methodologies are also described for various culture systems useful for testing the impacts of potential toxicants on hematopoietic stem cells both in vivo and in vitro.