Is Chronic Exposure to Low-Dose Organochlorine Pesticides a New Risk Factor of T-cell Immunosenescence?

Alterations in murine macrophage reactivity and bactericidal efficacy following exposure to an environmentally relevant mixture of organochlorine pesticide compounds

While there are a number of factors which may promote chronic inflammation, a major factor is pro-inflammatory activation of resident and infiltrating macrophages. Recently, exposures to persistent organic pollutants including organochlorine (OC) pesticides have been implicated in dysregulation of macrophage function. However, the majority of these studies examined single compound effects and not mixture-based effects. To this end, the present study investigated the effects of an environmentally relevant mixture of three prevalent OC pesticide compounds on macrophage function. Briefly, J77A.1 macrophages were exposed to a mixture of dichlorodiphenyldichloroethylene, trans-nonachlor, and oxychlordane (DTO; 0.2-20 μM) for 24 h then effects on cell viability, caspase 3/7 activity, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), antibacterial activity, and pro-inflammatory cytokine production were determined. Exposure to DTO significantly increased caspase activity and ROS production. The highest concentration of DTO significantly increased Staphylococcus aureus uptake while decreasing phagolysosome formation and bactericidal efficacy. Lastly, exposure to DTO significantly increased basal production of Mcp-1. Taken together, the present study demonstrates an environmentally relevant mixture of OC pesticide compounds increases macrophage ROS and Mcp-1 production while decreasing macrophage bactericidal efficacy which may adversely affect macrophage function and increase susceptibility to S. aureus infection.

Organic food and internal exposure to pollutants among Flemish adolescents

Contrary to the initial hypothesis, Flemish adolescents who reported consuming organic food at least 7.5 times per week did not exhibit reduced internal exposure to the tested recently used pesticides. After adjustment for gender, age, country of origin, socioeconomic status, body mass index, consumption of high-fat foods and foods linked to organic food consumption, and concerning organochlorine derivatives and lead, additional adjustment for the duration of breastfeeding expressed in weeks, they displayed slightly elevated internal exposure to organochlorine derivatives, lead, methyl arsenate, and toxic relevant arsenic. A comparison was also made between the correlation of internal exposure to pollutants with the frequency of organic food consumption on one hand and the total consumption of equivalent products from all sources on the other. Regarding potatoes, vegetables, and fruits, no clear trends were observed. Regarding eggs, there was a trend towards higher internal exposures with organic food consumption, significant for trans-nonachlor, PCB118, and 2,4-dichlorophenoxyacetic acid, and marginally significant for glyphosate. For dairy, there was a trend towards higher internal exposures with organic food consumption, significant for perfluorononanoic acid and marginally significant for PCB153. Regarding nuts and seeds, the higher internal exposure to dichlorophenoxyacetic acid and the lower exposure to 3-phenoxybenzoic acid were marginally significant, while there was also a trend towards higher internal exposure to other pollutants with organic food consumption, significant for PCB118, PCB153, and sum PCBs, and marginally significant for trans-nonachlor. Concerning breakfast cereals and muesli, no clear trends were observed.

Sarcopenia assessed by skeletal muscle mass volume is a prognostic factor for oncological outcomes of rectal cancer patients undergoing neoadjuvant chemoradiotherapy followed by surgery

INTRODUCTION

Recently, sarcopenia has been reported to be associated with poor postoperative outcomes in various cancers. However, its clinical significance for rectal cancer patients undergoing neoadjuvant chemoradiotherapy (NACRT) followed by surgery remains unknown.

MATERIALS AND METHODS

This study included 46 patients with locally advanced rectal cancer who underwent curative surgery after NACRT. Sarcopenia was assessed by measuring the cross-sectional psoas muscle area (PA) at L3 and total bilateral psoas muscle volume (PV). Patients with a lower PV or PA value than the median were assigned to the sarcopenia group while others were assigned to the non-sarcopenia group. Clinical outcomes were then compared between groups.

RESULTS

The sarcopenia group included 22 patients. The rate of overall postoperative complications did not differ between groups. Five-year relapse-free survival (RFS) was significantly lower in the sarcopenia group when sarcopenia was assessed by PV after NACRT (44.0% vs. 82.6%, P = 0.00494). In contrast, RFS did not differ between groups when sarcopenia was assessed by PA. Multivariable analysis identified PV after NACRT as the most significant risk factor for RFS (hazard ratio 4.00; 95% CI 1.27-12.66, P = 0.018).

CONCLUSION

Sarcopenia assessed by total PV after NACRT may be an accurate and reliable predictor of poor oncological outcomes in rectal cancer patients.

Agricultural Pesticides and Shingles Risk in a Prospective Cohort of Licensed Pesticide Applicators

BACKGROUND

Some pesticides are immunotoxic and have been associated with an increased risk of immune-mediated diseases. The risk of shingles, the clinical reactivation of varicella-zoster virus, increases with aging and immunosuppression; little is known about its associations with pesticides.

OBJECTIVE

We examined the use of agricultural pesticides in relation to incident shingles in a prospective cohort of licensed pesticide applicators.

METHODS

The study sample included 12,820 (97% male) farmers (enrolled in 1993-1997 in North Carolina and Iowa), who were followed for a median of 12 y (interquartile range: 11-13). Shingles was self-reported at enrollment and at follow-up. We evaluated ever-use of 48 agricultural pesticides reported at study enrollment in relation to shingles risk and considered exposure-response for intensity-weighted lifetime days (IWLDs) of use. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard models, adjusting for state, and allowing estimates to vary by median attained age (60 y).

RESULTS

Incident shingles was reported by 590 participants. Associations were positive (HRs>1.2) for ever- vs. never-use of eight insecticides, three fumigants, two fungicides, and five herbicides, and exposure-response trends were seen across increasing quartiles (Q3 and Q4>Q1) or tertiles (T3 and T2>T1) of IWLDs for four insecticides [permethrin (crops), coumaphos, malathion, and lindane], two fumigants (carbon tetrachloride/carbon disulfide and methyl bromide), and three herbicides [alachlor, trifluralin (<60 years of age) and 2,4-dichlorophenoxyacetic acid]. Shingles was not associated with total years or days per year mixed or applied any pesticides, but in older participants, shingles was associated with a history of a high pesticide exposure event [HR=1.89 (95% CI: 1.45, 2.45)].

CONCLUSIONS

Several specific pesticides were associated with increased risk of shingles in farmers, especially at higher levels of cumulative use. These novel findings, if replicated in other populations, could have broader implications for the potential effects of pesticides on vaccine efficacy and susceptibility to other infections. https://doi.org/10.1289/EHP7797.

Serum concentrations of persistent organic pollutants and colorectal cancer risk: A case-cohort study within Korean National Cancer Center Community (KNCCC) cohort

BACKGROUND & AIMS

Recent prospective cohort studies have suggested that circulating persistent organic pollutants (POPs) may be associated with the development of cancers. We investigated the association between pre-diagnostic serum concentrations of POPs and colorectal cancer (CRC) risk.

METHODS

A case-cohort study within a community-based prospective cohort was performed, including 104 CRC cases and 235 subcohort participants. Serum concentrations of POPs were measured by high resolution gas chromatography/high-resolution mass spectrometry. Multivariable Cox proportional hazards regression models were used.

RESULTS

The association between serum concentrations of organochlorine pesticides (OCs) and CRC risk was significant (cis-heptachlor epoxide: 3rd tercile [HR (95% CI): 2.76 (1.25-6.07); trans-nonachlor: 2nd tercile [HR (95% CI): 3.90 (1.56-9.75)], 3rd tercile [HR (95% CI): 4.86 (1.95-12.16)]); p,p'-DDD: 2nd tercile [HR (95% CI): 6.02 (2.05-17.70)], 3rd tercile [HR (95% CI): 7.43 (2.42-22.84)]). Certain polychlorinated biphenyls (PCBs) congeners were significantly associated with CRC risk (PCB-105: 3rd tercile HR [95% CI]: 3.15 [1.38-7.19], PCB-118: 3rd tercile HR [95% CI]: 2.68 [1.22-5.92]; PCB-138: 2nd tercile [HR (95% CI): 2.51 (1.19-5.28)], 3rd tercile [HR (95% CI): 3.27 (1.50-7.12)]; PCB-153: 2nd tercile [HR (95% CI): 3.93 (1.81-8.54)], 3rd tercile [HR (95% CI): 5.02 (2.09-12.07)]; PCB-156: 2nd tercile [HR (95% CI): 2.61 (1.21-5.59)], 3rd tercile [HR (95% CI): 4.07 (1.73-9.61)]; PCB-180: 2nd tercile [HR (95% CI): 2.58 (1.15-5.78)], 3rd tercile [HR (95% CI): 4.01 (1.68-9.59)]).results CONCLUSIONS: This study suggests that serum concentrations of POPs could increase the CRC risk in the general population.

Impact of environmental exposure to persistent organic pollutants on lung cancer risk

BACKGROUND

Recent studies suggest that high pre-diagnostic serum concentrations of persistent organic pollutants (POPs) might result in the development of cancers in the general population. However, the association between pre-diagnostic serum POP concentrations and lung cancer risk has not been studied. Here, we evaluated associations between low-dose environmental exposure to POPs and risk of lung cancer using pre-diagnostic serum samples in a case-cohort study based on a population-based prospective cohort.

METHODS

We conducted a case-cohort study based on the Korean National Cancer Center Community Cohort, from which we included 118 lung cancer cases and 252 controls. Serum concentrations of POPs were measured by high resolution gas chromatography/high-resolution mass spectrometry, and data were analyzed using multivariable Cox proportional-hazards regression models.

RESULTS

Risk of lung cancer increased per unit increase in the natural log-transformed concentrations of the sum of chlordane congeners, total PCBs, and all PCBs subgrouped by the number of chlorines or ortho- substituted chlorines on the molecules, except for tri/tetrachlorobiphenyls, in all models. Among individual POP analytes with a detection rate >80%, after Bonferroni adjustment, only trans-nonachlor was associated with lung cancer risk. In categorical models, risk of lung cancer was associated with serum concentration of chlordane (4th vs. 1st quartile, hazard ratio [95% confidence interval], 8.79 [2.77-27.97]). Dose-dependent relationships were also found between risk of lung cancer and serum concentrations of PCBs regardless of their degree of chlorination, substitution pattern, or binding affinity to receptors (total PCBs, P = 0.002; mid-chlorinated PCBs, P = 0.004; high-chlorinated PCBs, P < 0.001; non- and mono-ortho PCBs, P = 0.031; di-ortho PCBs, P = 0.003; PCBs with dioxin-like activity, P = 0.011; non-dioxin-like non-/mono-ortho PCBs, P = 0.060).

CONCLUSIONS

Serum concentrations of chlordane and PCBs are associated with risk of lung cancer in the general population, even decades after the ban on their production and use.

Association of colorectal polyps and cancer with low-dose persistent organic pollutants: A case-control study

BACKGROUND

Low-dose persistent organic pollutants (POPs) have recently been linked to immunosenescence, a key mechanism in carcinogenesis, as well as many aging-related chronic diseases. Since feces are the main excretion route of POPs, the large intestine is a potential target organ for these pollutants. We performed a case-control study to evaluate whether exposure to low-dose POPs is related to the risk of colorectal polyps and cancer.

METHODS

A total of 277 participants were recruited from one hospital: 99 cancer patients, 102 polyp patients, and 76 control subjects. As typical examples of POPs, we measured the serum concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs).

RESULTS

Across the tertiles of the summary measure of POPs, the adjusted odds ratios (ORs) of colorectal polyps and cancer were 2.8 (1.2-6.8) (Ptrend = 0.01) and 3.0 (1.0-8.8) (Ptrend = 0.02), respectively, for subjects in the highest tertile. When OCPs and PCBs were analyzed separately, OCPs were linked to an increased risk of both polyps and cancer; the adjusted ORs were 2.3 (0.9-5.7) (Ptrend = 0.05) for polyps and 3.6 (1.1-11.8) (Ptrend< 0.01) for cancer. However, PCBs were only significantly associated with a high risk of polyps but not cancer; the adjusted OR was 2.8 (1.2-6.6) (Ptrend = 0.01).

CONCLUSION

Chronic exposure to low-dose POPs may be associated with an increased risk of colorectal polyps and cancer. Our findings suggest the carcinogenic potential of strong lipophilic chemical mixtures such as POPs which are accumulated in adipose tissue, released to circulation, and eliminated through feces.