Association and risk of circulating inflammatory markers with hyperglycemia in coal-burning arsenicosis.

BACKGROUND: Several lines of evidence support a significant relationship between exposure to arsenic and diabetes. However, the underlying pathophysiological mechanisms remain incompletely elucidated. OBJECTIVE: This study examined the association and risk of circulating inflammatory mediators with hyperglycemia in coal-induced arsenicosis. METHODS: A cross-sectional study was conducted in the typical coal-burning area in which arsenicosis is endemic in Xingren County, Guizhou, China. A total of 299 arsenicosis subjects and 137 non-arsenic exposed volunteers were recruited for the present study. Participant's hyperglycemia-related parameters, including fasting blood glucose (FBG), fasting serum insulin (FINS), homeostasis model assessment for both insulin resistance (HOMA-IR) and pancreatic ß-cell function (HOMA-ß), as well as circulating inflammatory biomarkers i.e., Interleukins-1ß (IL-1ß), IL- 2, IL - 6, IL-10, IL- 17, IL-18 and TNF-α), were determined and analyzed after completing questionnaire investigation and physical examination. RESULTS: The results clearly showed that coal-burning arsenic exposure was significantly associated with hyperglycemia-related outcomes. Specifically, arsenicosis subjects from the coal-burning endemic area showed a higher level of FBG (median 5.87 mmol/L vs. 4.65 mmol/L) and increased prevalence of hyperglycemia (26.76% vs.16.79%) than reference subjects from the non-arsenic endemic area. Increased HOMA-IR (median 1.93 vs.1.44) and declined HOMA-ß (median 96.23 vs. 84.91) were also noted in arsenicosis subjects. Moreover, arsenic exposure was significantly associated with the increased risk of hyperglycemia (adjusted OR = 2.32, 95% CI: 1.37,3.93). In addition, a positive association between arsenic exposure and inflammatory response was observed, and the alteration in circulating inflammatory markers were found to be significantly associated with hyperglycemia-related parameters. Meanwhile, there was a positive relationship between elevated circulating IL-1ß, IL-18, IL-6, as well as decreased IL-10 and the increasing risk of arsenic-induced hyperglycemia [adjusted OR = 2.19 (95% CI: 1.26, 3.13);1.13 (95%CI: 1.08, 1.37); 1.19 (95% CI: 1.13, 1.56); 1.15(95% CI: 1.05, 1.36); respectively]. Path analysis further revealed that the mediating effect of IL-1ß and IL-18 on the relationship between arsenic exposure and hyperglycemia was closely associated with pancreatic ß-cell dysfunction, while those of IL-6 and IL-10 on the association between arsenic exposure and hyperglycemia were partially through insulin resistance. CONCLUSIONS: This population-based study indicated that arsenic exposure has a clear disruptive effect on glucose homeostasis, and an elevated inflammatory response was implicated in the risk of arsenic-induced hyperglycemia.

Imbalanced inflammatory response in subchronic arsenic-induced liver injury and the protective effects of Ginkgo biloba extract in rats: Potential role of cytokines mediated cell-cell interactions.

Arsenic is a well-known environmental toxicant and carcinogen, which has been epidemiologically proved related to the increased hepatic disorders. Researches have shown that aseptic inflammation and abnormal immune response are associated with arsenic-induced liver injury. However, the immunotoxic effects of liver have not been extensively characterized. Ginkgo biloba extract (GBE), a natural products of G. biloba leaves with proven anti-inflammatory and potential immunoregulatory activities, was used as intervention agent to explore its protective effects on arsenic-induced hepatotoxicity. Thus, the underlying mechanism of the immunotoxic effects on arsenic-induced liver injury were investigated in 2.5, 5.0, and 10.0 mg/kg NaAsO2 of Wistar rats for 16 weeks. Subsequently, GBE was used as intervention agent in 50 mg/kg for 6 weeks after cessation of arsenic exposure. The ratio of Th17 to Treg cells in peripheral blood as well as the secretion of inflammatory cytokines IL-17A, IL-6, TGF-ß1, and IL-10 in serum and liver were detected. Meanwhile, the notable activation of aseptic inflammation-related molecule TLR4 and its downstream targets MyD88 and NF-κB in the liver were observed. In this work, we confirmed that subchronic exposed to arsenic triggered the infiltration of inflammatory cells in rat liver, coupled with obvious histopathological changes and aberrant hepatic serum biochemical parameters. Meanwhile, imbalanced immune response was verified by the notable abnormal ratio of Th17 to Treg cells in peripheral blood as well as the secretion of inflammatory cytokines IL-17A, IL-6, TGF-ß1, and IL-10 in serum and liver of arsenic exposed rats. Further, the level of TLR4, MyD88, and NF-κB in liver both transcription and translation activity were raised. Subsequently, GBE markedly mitigated arsenic-induced liver injury, most impressively, post treatment with GBE prominently suppressed the overactivated inflammatory-related TLR4-MyD88-NF-κB pathway and evidently decreased the secretion of inflammation cytokines. Meanwhile, the disturbance of pro- and anti-inflammatory response was reversed. We concluded that the disruption of pro- and anti-inflammatory T-cells balance caused by cytokines mediated cell-cell interactions may be one of the mechanisms underlying arsenic-induced liver injury and that GBE intervention exerts an evidence protective effects, which might be closely associated with the suppression of inflammatory-related TLR4 pathway.

[CCL2 promotes angiogenesis of primary rat cardiac microvascular endothelial cells].

The aim of the present study was to investigate the role of chemokine CCL2 in angiogenesis of primary adult rat cardiac microvascular endothelial cells (CMEC). The rat CMECs were isolated and identified through morphology examination and immunostaining with CD31 and factor VIII antibodies. The angiogenesis of CMEC on Matrigel was evaluated at different time points. The expression and secretion of CCL2 during the process of angiogenesis was detected by real-time RT-PCR and ELISA, respectively. The results showed that, the primary rat CMEC was isolated successfully, and the angiogenesis of CMEC was significantly induced after Matrigel treatment for 4 h. The expression of CCL2 and CCR2 were increased during angiogenesis, and the secretion of CCL2 was detected after 2 h of angiogenesis and reached the peak concentration of 1 588.1 pg/mL after 4 h. Either CCL2 blocking antibody or CCR2 antagonist significantly reduced the angiogenesis of CMEC. These results suggest that CCL2 is secreted during the process of angiogenesis of CMEC, and CCL2/CCR2 signaling pathway may play an important role in promoting angiogenesis.

Ginkgo biloba extract attenuates the disruption of pro-and anti-inflammatory T-cell balance in peripheral blood of arsenicosis patients.

Endemic arsenicosis is a public health problem that affects thousands of people worldwide. However, the biological mechanism involved is not well characterized, and there is no specific treatment. Exposure to arsenic may be associated with immune-related problems. In the present work, we performed an investigation to determine whether the Th17/Treg balance was abnormal in peripheral blood mononuclear cells (PBMCs) of patients with arsenicosis caused by burning coal. Furthermore, we investigated the effect of Ginkgo biloba extract (GBE) on the Th17/Treg imbalance in patients with arsenicosis. In this trial, 81 arsenicosis patients and 37 controls were enrolled. The numbers of Th17 and Treg cells, as well as related transcription factors and serum cytokines, were determined at the beginning and end of the study. Patients with arsenicosis exhibited higher levels of Th17 cells, Th17-related cytokines (IL-17A and IL-6), and the transcription factor RORγt. There were lower levels of Treg cells, a Treg-related cytokine (IL-10), and the transcription factor Foxp3 as compared with controls. There was a positive correlation between the levels of Th17 cells and IL-17A and the levels of arsenic in hair. Arsenicosis patients were randomly assigned to a GBE treatment group or a placebo group. After 3 months of follow-up, 74 patients completed the study (39 cases in the GBE group and 35 in the placebo group). Administration of GBE to patient upregulated the numbers of Treg cells and the level of IL-10 and downregulated the numbers of Th17 cells and the levels of cytokines associated with Th17 cells. The mRNA levels of Foxp3 and RORγt were increased and decreased, respectively. These results indicated that exposure to arsenic is associated with immune-related problems. The present investigation describes a previously unknown mechanism showing that an imbalance of pro- and anti-inflammatory T cells is involved in the pathogenesis of arsenicosis and that a GBE exerts effects on arsenicosis through regulation of the pro- and anti-inflammatory T cell balance.

Heat shock transcription factor 1 affects kidney tubular cell migration by regulating the TGF­ß1­Smad2/3 signaling pathway.

Cell migration is important for renal recovery from tubular cell injury. Heat shock transcription factor 1 (HSF1) is a well­studied regulatory factor that is active during acute kidney injury. HSF1 is also involved in the migration process during tumor metastasis. Therefore, we hypothesized that HSF1 may promote the recovery of renal function by affecting kidney tubular cell migration. A wound healing assay was used to examine the cell migration rate. The results demonstrated that the migration of rat kidney proximal tubular cells (RPTCs) was increased following knockdown of HSF1. In addition, the invasion ability of HSF1 knockdown RPTCs was also significantly upregulated. The present study also identified that transforming growth factor­ß1 (TGF­ß1) was highly expressed at the edge of the wound in control cells, and its expression was further increased upon knockdown of HSF1. Inhibition of TGF­ß1 signaling prevented RPTC HSF1 knockdown cell migration, suggesting that HSF1­regulated RPTC cell migration was dependent on the TGF­ß1 signaling pathway. Furthermore, phosphorylation of TGF­ß1 and Smad2/3 was induced in HSF1 knockdown cells. Together, these results suggest that HSF1 may suppress RPTC migration by inhibiting the activation of the TGF­ß1­Smad2/3 signaling pathway.

Association and risk of five miRNAs with arsenic-induced multiorgan damage.

Chronic exposure to arsenic remains a major environmental public health concern worldwide, affecting hundreds of millions of people. Arsenic-induced multiorgan damage and miRNA expression changes after arsenic exposure have been determined, but their associations and risks have not been fully examined. In this study, we measured the expression levels of five miRNAs in plasma from control and arsenic poisoned populations, and we analyzed the relationship between miRNAs and multiorgan damage. The results clearly show that the upregulation of miR-155 expression can increase the risk of arsenic induced skin damage (OR = 10.55; 95% CI: 6.02, 18.47); further, there is a link between the expression of miR-21 (OR = 11.84; 95% CI: 5.34, 26.28) and miR-145 (OR = 2.39; 95% CI: 1.61, 3.55) and liver damage, and miR-191 and kidney damage (OR = 3.65; 95% CI: 1.49, 8.93). In addition, we analyzed the diagnostic value of miRNAs associated with specific organ damage in arsenic-induced multiorgan damage. It was found that the miR-155 has a certain diagnostic value in arsenic-induced skin damage (AUC = 0.83), miR-21 and miR-145 have diagnostic value for liver damage (AUC = 0.80, 0.81) and miR-191 has diagnostic value for kidney damage (AUC = 0.83). This study provides the first comprehensive assessment of the association and risk of five miRNAs with arsenic-induced multiorgan damage. The study can provide a scientific basis for further understanding the causes of arsenic-induced multiorgan damage, identification of possible biological markers, and improvement of targeted prevention and control strategies.

Enhanced glycolysis, regulated by HIF-1α via MCT-4, promotes inflammation in arsenite-induced carcinogenesis.

Arsenite is well established as a human carcinogen, but the molecular mechanisms leading to arsenite-induced carcinogenesis are complex and elusive. Accelerated glycolysis, a common process in tumor cells called the Warburg effect, is associated with various biological phenomena. However, the role of glycolysis induced by arsenite is unknown. We have found that, with chronic exposure to arsenite, L-02 cells undergo a metabolic shift to glycolysis. In liver cells exposed to arsenite, hypoxia inducible factor-1α (HIF-1α) and monocarboxylate transporter-4 (MCT-4) are over-expressed. MCT-4, directly mediated by HIF-1α, maintains a high level of glycolysis, and the enhanced glycolysis promotes pro-inflammatory properties, which are involved in arsenite carcinogenesis. In addition, serum lactate and cytokines are higher in arsenite-exposed human populations, and there is a positive correlation between them. Moreover, there is a positive relationship between lactate and cytokines with arsenic in hair. In sum, these findings indicate that MCT-4, mediated by HIF-1α, enhances the glycolysis induced by arsenite. Lactate, the end product of glycolysis, is released into the extracellular environment. The acidic microenvironment promotes production of pro-inflammatory cytokines, which contribute to arsenite-induced liver carcinogenesis. These results provide a link between the induction of glycolysis and inflammation in liver cells exposed to arsenite, and thus establish a previously unknown mechanism for arsenite-induced hepatotoxicity.

Circulating miRNAs and their target genes associated with arsenism caused by coal-burning.

Endemic arsenism, caused by burning coal containing high levels of arsenic, is found only in the Guizhou and Shanxi Provinces of China. Dysregulated microRNAs (miRNAs), detected in the blood, are emerging as promising biomarkers. At present, little is known about the change and clinical efficacy of circulating miRNAs in patients with endemic arsenism produced by burning of coal. Here, we determined, by using TaqMan Human miRNA Array Chips, the differential expression of plasma miRNAs between patients with arsenism caused by coal-burning and a control group. Four increased miRNAs (miR-21, miR-145, miR-155, and miR-191) were verified in a larger sample by quantitative real-time PCR. Furthermore, bioinformatics and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to associate changes in plasma levels of the miRNAs with their functions and their effects on various pathways. The results of chip array assays show that the levels of miR-21, miR-141, miR-148a, miR-145, miR-155, miR-191, miR-218, and miR-491 were most prominently increased and that the levels of miR-200b, miR-200c, miR-26, and miR-34c were decreased. The qRT-PCR results confirm that the circulating levels of miR-21, miR-145, miR-155, and miR-191 are increased in patients with arsenism caused by coal-burning. KEGG analyses show that these miRNAs inhibit the target genes of pathways related to immune inflammation, oxidative stress, and DNA damage repair. Therefore, the four miRNAs may be biomarkers of endemic arsenism caused by coal-burning. Further studies with larger samples should be performed to confirm these findings and to elucidate the underlying mechanisms.