Objective
To investigate the expression of transcription factor forkhead/winged helix transcription factor 3 (Foxp3), immune factor transforming growth factor-beta 1 (TGF-β1), and T-lymphocyte activation related factor interleukin-2 (IL-2) in peripheral blood of patients with coal-burning arsenic poisoning, and to analyze the effects of arsenic exposure on immune function.
Methods
A case-control study was conducted to investigate 149 cases [94 males and 55 females, (50.69 ± 6.14) years old] of arsenic poisoning in Yuzhang coal-burning arsenic poisoning area, southwestern Guizhou Province, and the cases were diagnosed based on the Diagnosis of Endemic Arsenicosis (WS/T 211-2015) and confirmed by clinical review. According to skin damage, the patients were divided into mild arsenic poisoning group (39 cases), moderate arsenic poisoning group (54 cases) and severe arsenic poisoning group (56 cases); and 41 cases [12 males and 29 females, (45.76 ± 7.88) years old] of non-arsenic exposed residents from 12 km of Yuzhang coal-burning area were selected as control group. Morning urine and peripheral blood samples were collected with informed consent. Urine arsenic content was measured by inductively coupled plasma mass spectrometry (ICP-MS). Urine arsenic was corrected by creatinine (Cr). Detection of regulatory T cell (Treg)-specific transcription factor Foxp3 gene expression in human peripheral blood was done by real-time fluorescence quantitative PCR, and the levels of Treg-related immune factor TGF-β1 and IL-2 in serum were detected by enzyme linked immunosorbent assay (ELISA).
Results
The urinary arsenic contents [median (quartile): 29.13 (19.75-54.50), 31.81 (17.52-53.31), 30.51 (18.35-45.76) μg/g Cr] in each arsenic poisoning group were higher than that in the control group [21.62 (17.65-28.44) μg/g Cr, P < 0.05]. The expression levels of Foxp3 mRNA in peripheral blood of each arsenic poisoning group [median (quartile): 0.58 (0.17-1.27), 0.32 (0.17-0.61), 0.33 (0.13-0.62)] were significantly lower than that in the control group [0.87 (0.64-1.50), P < 0.05]; compared with mild arsenic poisoning group, the expression of Foxp3 mRNA in peripheral blood of moderate and severe arsenic poisoning groups decreased (P < 0.05). The contents of serum TGF-β1 [(13.14 ± 5.19), (12.85 ± 5.51), (12.78 ± 4.95) μg/L] in each arsenic poisoning group were significantly higher than that in the control group [(3.90 ± 1.53) μg/L, P < 0.05]. The levels of IL-2 in serum of each arsenic poisoning group [(9.85 ± 5.38), (11.64 ± 6.40), (12.27 ± 6.19) ng/L] were lower than that in the control group [(34.30 ± 4.84) ng/L, P < 0.05]; the serum level of IL-2 in severe arsenic poisoning group was higher than that in mild arsenic poisoning group (P < 0.05).
Conclusions
Arsenic exposure can cause abnormal changes of Treg-specific transcription factor Foxp3 and related immune factors TGF-β1 and IL-2 in peripheral blood of patients. It is suggested that Treg dysfunction may be related to arsenic poisoning.
Key words:
Arsenic poisoning; Coal; Foxp3; Immunologic factors
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.
Increasing evidence supports the role of arsenic in dysregulated immune and inflammation responses, while, safe and effective treatments have not been fully examined. Rosa roxburghii Tratt (RRT), a traditional Chinese edible fruit with potential immunoregulatory activities, was considered as a dietary supplement to explore its protective effects and possible mechanism in arsenic-induced dysregulated inflammation responses. We enrolled 209 arsenicosis patients and 41 controls to obtain baseline data, including the degree of arsenic poisoning prior to the RRT juice (RRTJ) intervention. Then, based on criteria of inclusion and exclusion and the principle of voluntary participation, 106 arsenicosis patients who volunteered to receive treatment were divided into RRTJ (n = 53) and placebo (n = 53) groups randomly. After three months follow-up, 89 subjects (46 and 43 of the RRTJ and placebo groups, respectively) completed the study and were examined for the effects and possible mechanisms of RRTJ on the Th17 cells-related pro-inflammatory responses in peripheral blood mononuclear cells (PBMCs). The PBMCs had higher levels of Th17 and Th17-related inflammatory cytokines IL-17, IL-6, and RORγt. Furthermore, the gene expressions of STAT3 and SOCS3 in PBMCs increased and decreased, respectively. Conversely, RRTJ decreased the number of Th17 cells, secretion of IL-17, IL-6, RORγt, and relative mRNA levels of STAT3, and increased the transcript levels of SOCS3. This study provides limited evidence that possible immunomodulatory effects of RRTJ on the critical regulators, IL-6 and STAT3, of the Th17 cells in arsenicosis patients, which indicated that IL-6/STAT3 pathway might appear as a potential therapeutic target in arsenicosis.
Objective
To observe the change of T helper 17 (Th17), regulatory T cell (Treg) as a percentage of lymphocytes and the Th17/Treg ratio in peripheral blood of patients with coal-burning-borne arsenic poisoning, and to explore the role of Th17 cells and Treg cells balance in arsenic-induced immune injury.
Methods
A case-control study was conducted to investigate 149 cases of arsenic poisoning in Yuzhang arsenic poisoning area in the southwestern Guizhou Province, and the age was (50.69 ± 6.14) years old, including 94 males and 55 females. The diagnosis was based on the Diagnosis of Endemic Arsenicosis (WS/T 211-2015), and the cases were divided into mild arsenic poisoning group (39 cases), moderate arsenic poisoning group (54 cases) and severe arsenic poisoning group (56 cases); forty-one residents of non-arsenic exposed villages about 12 km away from the diseased area were collected as control group, the age was (45.76 ± 7.88) years old, including 12 males and 29 females. Hair samples and peripheral blood were collected from the subjects. The content of hair arsenic was detected by inductively coupled plasma mass spectrometry (ICP-MS). The percentages of Th17 cells and Treg cells in peripheral blood lymphocytes were detected by flow cytometry, and changes in the ratio of Th17/Treg in each group were analyzed.
Results
The hair arsenic contents in control, mild, moderate, and severe arsenic poisoning groups [median (quartile)] were 0.12 (0.08-0.18), 0.20 (0.16-0.33), 0.25 (0.18-0.41), 0.28 (0.21-0.50) μg/g, and the differences were statistically significant between groups (H=52.22, P < 0.01), and the hair arsenic content in each arsenic poisoning group was higher than that of the control group (P < 0.05). The percentages of Th17 cells in peripheral blood lymphocytes of moderate and severe arsenic poisoning groups [(0.42 ± 0.21)%, (0.41 ± 0.23)%] were higher than that of the control group [(0.29 ± 0.16)%, P < 0.05]. The percentages of Treg cells in peripheral blood lymphocytes of mild, moderate and severe arsenic poisoning groups [(0.37 ± 0.18)%, (0.31 ± 0.19)%, (0.27 ± 0.18)%] were lower than that of the control group [(0.71 ± 0.20)%, P < 0.05]; with respect to the mild arsenic poisoning group, the percentage of Treg cells in severe arsenic poisoning group was reduced (P < 0.05). The ratios of Th17/Treg in mild, moderate and severe arsenic poisoning groups (1.17 ± 0.63, 1.56 ± 0.69, 1.83 ± 0.85) were higher than that of the control group (0.43 ± 0.22, P < 0.05); compared with mild arsenic poisoning group, the ratio of Th17/Treg in severe arsenic poisoning group was elevated (P < 0.05). Correlation analysis showed that the hair arsenic content was positively correlated with the percentage of Th17 cells in peripheral blood lymphocytes and the ratio of Th17/Treg (r=0.323, 0.608, P < 0.05), and negatively correlated with the percentage of Treg cells in peripheral blood lymphocytes (r=- 0.486, P < 0.05).
Conclusion
Coal-burning-borne arsenic poisoning can cause the proportion of Th17 cells in the peripheral blood of patients to increase in lymphocytes, and the proportion of Treg cells in lymphocytes to decrease, which in turn changes the balance of Th17/Treg, resulting in weakened immune tolerance and disorder the regulation of inflammatory response, thus participates in the occurrence and development of arsenic-induced immune damage.
Key words:
Arsenic poisoning; Coal; T helper 17; Regulatory T cell
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