Follistatin-like 1 (FSTL1) levels as potential early biomarker of cardiovascular disease in a Mexican population

Cardiovascular diseases (CVD) are the leading cause of death globally. In recent years, follistatin-like protein 1 (FSTL1) has been proposed as an emerging potential clinical biomarker of CVD, since its concentration is upregulated in heart failure. The aim of the present study was to evaluate the association of FSTL1 levels and classic biomarkers with the risk of CVD in Mexican population. A case-control study was carried out in patients with cardiovascular diseases (CVD), arterial hypertension, but not CVD (cardiovascular risk factor-CRF), and healthy controls (control group) from the Mexican Institute of Social Security. Lipid profile, homocysteine (Hcys), serum amyloid A (SAA), FSTL1 concentration, PON1 concentration and activities [Arylesterase (ARE), and Lactonase (LAC)] were evaluated. High levels of FSTL1 were found in the CRF group and a positive association of FSTL1 (OR = 4.55; 95% CI 1.29-16.04, p = 0.02) with the presence of arterial hypertension, as well as Hcys (OR, 3.09; 95% CI 1.23-7.76, p = 0.02) and SAA (OR, 1.03; 95% CI 1.01-1.05, p < 0.01) with the presence of CVD. LAC activity (OR, 0.26; 95% CI 0.07-0.94, p = 0.04) and PON1 concentration (OR, 0.17; 95% CI 0.05-0.62, p = 0.01) were associated with a decrease in OR belonging to the group with CVD. Our results suggest that FSTL1 may be a useful biomarker for monitoring cardiovascular risk in clinical settings. However, longitudinal studies are needed to evaluate how FSTL1 could influence the association of PON1 activity and Hcys with CVD.

Trends on deaths from acute pesticide poisoning in Mexico, 2000-2021

OBJETIVE

To provide a comprehensive analysis of mortality trends from acute pesticide poisoning in Mexico from 2000 through 2021.

METHODS

The governmental records of deaths from acute pesticide poisoning were used. The age-standardized years of life lost and aged-standardized mortality rates were estimated. Significant changes in trends of annual percentage change were identified using Joinpoint regression.

RESULTS

Between 2000 and 2021, mortality was primarily observed in individuals aged 15 to 19 years. Males were the most affected. Self-inflicted pesticide poisoning was the primary registered reason for death. The age-standardized mortality rate from acute pesticide poisoning was reduced from 2012 to 2021 (APC: -4.4; p=0.003).

CONCLUSION

This report is the first study about the mortality rate from acute pesticide poisoning in Mexico. The results provided evidence to consider in developing laws to prevent acute pesticide poisoning.

β-glucuronidase as a biomarker for assessing the exposure to anticholinergic pesticides: A meta-analysis

INTRODUCTION

The human exposure to anticholinergic pesticides has been associated with the development of various diseases. Therefore, several biomarkers have been proposed for biomonitoring human exposure to anticholinergic pesticides.

OBJECTIVE

This work evaluated the effect of human exposure to anticholinergic pesticides on β-glucuronidase (GUSB) levels.

METHODS

A systematic review was performed using PubMed, Web of Science, Scopus, and EBSCO databases up to December 2021. The statistical analysis employed standardized mean differences and meta-regression. And the trial sequential analysis was performed.

RESULTS

Nine studies were included. A monotonic relationship was observed between poisoning severity and GUSB. Furthermore, BuChE levels were correlated with GUSB levels.

CONCLUSIONS

The results indicated that GUSB levels could be used as a possible diagnosis biomarker in poisoning related to anticholinergic pesticide exposure. However, the use of GUSB to assess the chronic exposure to anticholinergic pesticides could be only performed in recent exposure (≈ 7 days after last exposure).

The situation of chlorpyrifos in Mexico: a case study in environmental samples and aquatic organisms

Chlorpyrifos (CPF) is one of the most commonly used organophosphate pesticides. Because CPF was described as a toxic compound without safe levels of exposure for children, certain countries in Latin America and the European Union have banned or restricted its use; however, in Mexico it is used very frequently. The aim of this study was to describe the current situation of CPF in Mexico, as well as its use, commercialization, and presence in soil, water, and aquatic organisms in an agricultural region of Mexico. Structured questionnaires were applied to pesticide retailers to determine the sales pattern of CPF (ethyl and methyl); in addition, monthly censuses were conducted with empty pesticide containers to assess the CPF pattern of use. Furthermore, samples of soil (48 samples), water (51 samples), and fish (31 samples) were collected, which were analyzed chromatographically. Descriptive statistics were performed. The results indicate that CPF was one of the most sold (3.82%) and employed OP (14.74%) during 2021. Only one soil sample was found above the CPF limit of quantification (LOQ); in contrast, all water samples had CPF levels above the LOQ (x̄ = 4614.2 ng/L of CPF). In the case of fish samples, 6.45% demonstrated the presence of methyl-CPF. In conclusion, the information obtained in this study indicates the need for constant monitoring in the area, since the presence of CPF in soil, water, and fish constitutes a threat to the health of wildlife and humans. Therefore, CPF should be banned in Mexico to avoid a serious neurocognitive health problem.

Hematological indices as indicators of inflammation induced by exposure to pesticides

Pesticide toxicity, both acute and chronic, is a global public health concern. Pesticides are involved in abnormal inflammatory responses by interfering with the normal physiology and metabolic status of cells. In this regard, inflammatory indices aggregate index of systemic inflammation (AISI), monocyte-to-high-density lipoprotein ratio, monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte platelet ratio (NLPR), neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune inflammation index, and systemic inflammation response index (SIRI) have been used as predictive markers of inflammatory status in several diseases and also in acute poisoning events. This study aimed to determine systemic inflammation indices and their relationship with pesticide exposure from urban sprayers in 302 individuals categorized into three groups (reference group and moderate and high exposure groups). The data suggest that the AISI, MLR, NLPR, and SIRI indices were significantly higher in the exposed groups compared with the reference group. In conclusion, this study proposes that inflammation indices warrant further attention in order to assess their value as early biomarkers of acute and chronic pesticide intoxication.

Preliminary survey of the occurrence of mycotoxins in cereals and estimated exposure in a northwestern region of Mexico

Mycotoxins have several toxicological implications. In the present study, we evaluate the presence of aflatoxin B₁ (AFB₁), ochratoxin A (OTA), and fumonisin (FB₁) in paddy rice, polished rice, and maize from the fields and markets in Nayarit State (Mexico). The results indicated the presence of AFB₁ in 21.21% of paddy rice samples and 11.11% of market maize samples. OTA was present in only 3.03% (one sample) of paddy rice samples. FB₁ was detected in 87.50% and 88.88% of maize samples from field and market, respectively. The estimated human exposure was calculated for FB₁ using the probable daily intake (PDI), which suggested that FB₁ could contribute to the development of diseases through the consumption of contaminated maize. Positive samples indicated that some rice and maize samples were not suitable for human consumption. Further efforts are needed to continue monitoring mycotoxins and update national legislation on mycotoxins accordingly.

Temephos, an organophosphate larvicide for residential use: a review of its toxicity

Temephos (O,O,O',O'-tetramethyl O,O'-thiodi-p-phenylene bis(phosphorothioate)) is a larvicide belonging to the family of organophosphate pesticides used for the control of different vectors of diseases, such as dengue, Zika, chikungunya, and dracunculiasis. The aim of this review was to discuss the available published information about temephos toxicokinetics and toxicity in mammals. Temephos is quickly absorbed in the gastrointestinal tract, distributed to all organs, and then it accumulates mainly in adipose tissue. It is metabolized by S-oxidation, oxidative desulfuration, and hydrolysis reactions, with the possible participation of cytochrome P450 (CYP). Temephos is mainly eliminated by feces, whereas some of its metabolites are eliminated by urine. The World Health Organization classifies it as class III: slightly dangerous with a NOAEL (no-observed adverse effect level) of 2.3 mg/kg/day for up to 90 days in rats, based on brain acetylcholinesterase (AChE) inhibition. A LOAEL (lowest observable adverse effect level) of 100 mg/kg/day for up to 44 days in rats was proposed based on cholinergic symptoms. However, some studies have shown that temephos causes toxic effects in mammals. The inhibition of the enzyme acetylcholinesterase (AChE) is one of its main demonstrated effects; however, this larvicide has also shown genotoxic effects and some adverse effects on male reproduction and fertility, as well as liver damage, even at low doses. We performed an extensive review through several databases of the literature about temephos toxicokinetics, and we recommend to revisit current assessment of temephos with the new available data.

The Relationship between Cancer and Paraoxonase 1

Extensive research has been carried out to understand and elucidate the mechanisms of paraoxonase 1 (PON1) in the development of diseases including cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. This review focuses on the relationship between PON1 and cancer. The data suggest that PON1, oxidative stress, chronic inflammation, and cancer are closely linked. Certainly, the gene expression of PON1 will remain challenging to study. Therefore, targeting PON1, redox-sensitive pathways, and transcription factors promise prevention and therapy in the development of several diseases, including cancer.

Methylation patterns of the CDKN2B and CDKN2A genes in an indigenous population exposed to pesticides

The INK4 -ARF locus includes the CDKN2B and CDKN2A genes and is functionally relevant in the regulation of both cell proliferation and senescence. Studies have reported modifications of DNA methylation in this locus by exposure to environmental contaminants including pesticides; however, until now, specific methylation profiles have not been reported in genetically conserved populations exposed to occupational pesticides. The aim of this study was to determine the methylation profiles of the CDKN2B and CDKN2A genes in a genetically conserved population exposed to pesticides. A cross-sectional and analytical study was carried out in 190 Huichol indigenous persons. Information related to pesticide exposure, diet and other variables were obtained through the use of a structured questionnaire. Blood and urine samples were collected for methylation test and dialkylphosphates (DAP) determination, respectively. DNA methylation was measured by the pyrosequencing of bisulfite-treated DNA and DAP concentrations by gas chromatography-tandem mass spectrometry (GC/MS). The most frequent metabolite in the population was dimethylthiophosphate. The farmer group presented a higher methylation percentage of CDKN2B than the non-farmer group, but no differences in CDKN2A were observed between groups. A positive correlation between methylation of CpG site 3 of CDKN2B and time working in the field was observed in the farmer group. An association between methylation percentage of CDKN2B and age was also observed in the non-farmer group. These results suggest that pesticide exposure and exposure time in Huichol indigenous individuals could modify the methylation pattern of the CDKN2B gene.

Organophosphorus pesticide exposure biomarkers in a Mexican population

The organophosphate (OP) pesticides are neurotoxic compounds widely used around the world. Evaluation of OP exposure in human studies is important for enabling adequate data analyses and drawing accurate conclusions. The aim of this study was to analyze OP exposure biomarkers and their relationships in a Mexican population with different exposure levels. Dialkylphosphates (DAP) were determined through gas chromatography-mass spectrometry (GC-MSD); acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), arylesterase (AREase), basal paraoxonase 1 (PONase), and β-glucuronidase activities were detected using spectrophotometric methods. The albumin content was determined in a certified clinical laboratory. The DMTP metabolite was found in the highest concentration, and a negative and significant correlation between DAP and cholinesterase activity was observed. Our results suggested that BuChE is a considerably more sensitive biomarker than AChE. In addition, β-glucuronidase was positively correlated with albumin, BuChE, and PONase. In conclusion, our data strongly support the use of two or more biomarkers of exposure in human monitoring and the application of a strong and validated questionnaire.

Environmental and socio-cultural impacts on global DNA methylation in the indigenous Huichol population of Nayarit, Mexico

Alterations of global DNA methylation have been evaluated in several studies worldwide; however, Long Interspersed Nuclear Elements-1 (LINE-1) methylation in genetically conserved populations such as indigenous communities have not, to our knowledge, been reported. The aim of this study was to evaluate the relationship between LINE-1 methylation patterns and factors such as pesticide exposure and socio-cultural characteristics in the Indigenous Huichol Population of Nayarit, Mexico. A cross-sectional study was conducted in 140 Huichol indigenous individuals. A structured questionnaire was used to determine general and anthropometric characteristics, diet, harmful habits, and pesticide exposure. DNA methylation was determined by pyrosequencing of bisulfite-treated DNA. A lower level of LINE-1 methylation was found in the indigenous population when compared to a Mestizo population previously studied by our group. This difference might be due to the influence of the genetic admixture and differing dietary and lifestyle habits. The males in the indigenous population exhibited increased LINE-1 methylation in comparison to the females. Sex and alcohol consumption showed positive associations with LINE-1 methylation, while weight, current work in the field, current pesticide usage, and folate intake exhibited negative associations with LINE-1 methylation. The results suggest that ethnicity, as well as other internal and environmental factors, might influence LINE-1 methylation.

Relationship between butyrylcholinesterase activity and lipid parameters in workers occupationally exposed to pesticides

Exposure to organophosphate pesticides (OP) has been associated with the inhibition of cholinesterase enzymatic activity, such as butyrylcholinesterase (BuChE). Changes in BuChE activity have been associated with obesity, diabetes, hyperthyroidism, and metabolic syndrome. However, few studies have evaluated the effects of pesticides on both BuChE and lipid parameters. The aim of this study was to evaluate lipid parameters in urban sprayers and their association with BuChE activity. An analytical cross-sectional study was conducted in workers exposed to pesticides. The pesticide exposures were evaluated by the measurement of urinary dialkylphosphates. BuChE activity was determined spectrophotometrically in serum, and biochemical parameters were determined at a certified laboratory. Information regarding general characteristics, lifestyle, and other aspects was obtained from a structured questionnaire. The results showed variations in glucose, cholesterol, albumin, atherogenic index, creatinine, LDL, VLDL, triglycerides, and total lipids according to the level of exposure to pesticides in individuals with overweight and obesity. Furthermore, positive correlations between BuChE activity and lipid parameters were observed; these effects were associated with the body mass index. More studies are needed in human population to better elucidate the role of BuChE in lipid metabolism.

PON1 status and homocysteine levels as potential biomarkers for cardiovascular disease

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death. The mainly risks factors for CVD are diabetes, hypertension and high levels of homocysteine (Hcys), among others. Paraoxonase 1 (PON1) has been proposed as an antiatherogenic target for its ability to hydrolyzing oxi-Low-Density-Lipoproteins (LDL) and Hcys-thiolactone. Thus, the aim of the present study was to evaluate the association of Hcys levels, and the activities and concentration of PON1, as well as vitamin B from the diet with a risk for CVD.

METHODS

A case-control study was carry out in patients with cardiovascular diseases (CVD), Arterial hypertension, but not CVD (AH), and in healthy controls (control group) from the Mexican Institute of Social Security. Lipid profile, intake of vitamin B, Hcys, serum amyloid A (SAA), PON1 concentration, and PON1 activities (Arylesterase activity (ARE), Lactonase activity (LAC), and CMPA activity (CMPA)) were evaluated.

RESULTS

The CVD group had the highest concentration of Hcys and SAA than in the AH and control groups (p < 0.01). ARE, LAC, and CMPA activities and PON1 concentration were lowest in the CVD group. A positive-independent association between Hcys levels and CVD was found (OR = 2.09; 95% CI: 1.69-2.56) and this increase when it was adjusted by age, BMI, ApoA1, vitamin B intake, SAA, and PON1 (OR = 14.41; 95% CI: 1.75-118.71). LAC and CMPA, as well as PON1 concentration, were inversely associated with CVD.

CONCLUSION

LAC activity, PON1 concentration, and Hcys levels might be good biomarkers for CVD and their association could be modified by the intake of vitamin B.

PON1 lactonase activity and its association with cardiovascular disease

BACKGROUND

Paraoxonase 1 (PON1) is important in the development of atherosclerosis, and it has become the subject of intensive research. Our aim was to evaluate the association of serum PON1 activity and polymorphisms with cardiovascular disease (CVD) using four different substrates.

MATERIALS AND METHODS

Activity of PON1-related to arylesterase (AREase and 4-CMPAse), paraoxonase (PONase), and lactonase (LACase), and polymorphisms (A-162G, T-108C, L55M, and Q192R) were evaluated in subjects with CVD, cardiovascular risk factor (CFR), and controls. An ordered logistic-regression analysis of PON1 phenotypes was performed in the CVD group with respect to the control group.

RESULTS AND CONCLUSIONS

Logistic-regression analysis showed that CC-108 genotype was associated with CRF and CVD. The CVD group had the lowest activities of PON1. The LACase might be a better biomarker for CVD (OR, 0.52; 95% CI, 0.44-0.61) followed by CMPAse (OR, 0.82; 95% CI, 0.77-0.86), AREase (OR, 0.98; 95% CI, 0.97-0.99) and PONase (OR, 0.99, 95% CI, 0.99-0.99). Logistic regression of PON1 phenotypes by haplotypes showed that LACase activity was not influenced by the polymorphisms and that it could be a new potential biomarker in the development of CVD. Larger scale longitudinal studies are required.

Relationship between internal and external factors and the activity of PON1

Paraoxonase 1 (PON1) is an A-esterase calcium-dependent enzyme that is associated with high-density lipoprotein (HDL) and capable of hydrolyzing a wide variety of substrates, including organophosphate (OP) pesticides. The PON1 phenotype can be modulated by multiple internal and external factors, thereby affecting the catalytic capacity of the enzyme. The aim of this study was to evaluate factors that could modulate PON1 activity in a sample occupationally exposed to pesticides. A cross-sectional, descriptive, and analytical study was carried out with 240 workers. The participants were stratified according to their level of pesticide exposure as reference, moderate-exposure, and high-exposure groups. PON1 activities (arylesterase/AREase, CMPAase, and ssPONase (salt-stimulated)) were determined by spectrophotometry, and the Q192R and L55MPON1 genotypes by real-time PCR. The most frequent genotypes were heterozygous (QR) and homozygous (LL) for PON1Q192R and PON1L55M polymorphisms, respectively. The internal factors associated with the activity of PON1 were the PON1 genotypes (55 and 192) and biochemical parameters related to the lipid profile, in contrast, various external factors related to diet and harmful habits as well as with exposure to pesticides were associated with the activity of PON1. However, using a multivariate mixed ordinal regression model, we found a significant reduction of ssPONase activity in the high-exposure group compared with the reference group only in haplotypes QQLL and RRLL.

Modified CDKN2B (p15) and CDKN2A (p16) DNA methylation profiles in urban pesticide applicators

Gene-specific changes in DNA methylation by pesticides in occupationally exposed populations have not been studied extensively. Of particular concern are changes in the methylation profile of tumor-suppressor, such as CDKN2B and CDKN2A, genes involved in oncogenesis. The aim of this study was to evaluate the methylation profiles of CDKN2B and CDKN2A genes in urban pesticide applicators and their relationship with occupational exposure to pesticides. A cross-sectional study was conducted in 186 urban pesticide applicators (categorized as high or moderate exposures) and 102 participants without documented occupational exposures to pesticides. Acute and chronic pesticide exposures were evaluated by direct measurement of urinary dialkylphosphates, organophosphate metabolites, and a structured questionnaire, respectively. Anthropometric characteristics, diet, clinical histories, and other variables were estimated through a validated self-reported survey. DNA methylation was determined by pyrosequencing of bisulfite-treated DNA. Decreased DNA methylation of the CDKN2B gene was observed in pesticide-exposed groups compared to the non-exposed group. In addition, increased methylation of the CDKN2A promoter was observed in the moderate-exposure group compared to the non-exposed group. Bivariate analysis showed an association between CDKN2B methylation and pesticide exposure, general characteristics, smoking status, and micronutrients, while changes in CDKN2A methylation were associated with pesticide exposure, sex, educational level, body mass index, smoking status, supplement intake, clinical parameters, and caffeine consumption. These data suggest that pesticide exposure modifies the methylation pattern of CDKN2B and CDKN2A genes and raise important questions about the role that these changes may play in the regulation of cell cycle activities, senescence, and aging.

Genotypes of Common Polymorphisms in the PON1 Gene Associated with Paraoxonase Activity as Cardiovascular Risk Factor

BACKGROUND

Paraoxonase-1(PON1) exhibits hydrolytic activity and prevents the oxidation of high and low-density lipoproteins. Polymorphisms in the PON1 gene have been associated with variations in paraoxonase activity and with the risk of coronary artery disease (CAD).

AIM OF THE STUDY

This study analyzed the association between the frequencies of genotypes of the L55 M and Q192 R SNPs in the PON1 gene with the PON1 activity and with CAD risk factors.

METHODS

Women, determined by body composition, biochemical markers, and arylesterase (AREase) and paraoxonase (CMPase) activities were studied. Genotyping of L55 M and Q192 R polymorphisms was performed by TaqMan. Seventeen studies were used in the meta-analysis.

RESULTS

A significant decrease in PON1 activity in carrying the LM/MM and QQ genotypes is identified, correlations are found between the AREase activity with glucose, cholesterol and atherogenic risk index. Carriers of the LM or MM genotype were related with obesity (OR = 1.6; p = 0.039), and the MQ haplotype has an effect on the decrease in AREase (β = ‒22.4; p <0.001) and CMPase (β = ‒3.8; p <0.001). In addition, a lower proportion of Native American admixture was observed in women with LM or MM genotype, while it was higher for the European proportion compared with the LL genotype (p <0.001).

CONCLUSIONS

The LL-L55 M and QR-Q192 R genotypes are identified as the most frequently in the different states or cities of the country, and genotypic proportions are different, probably depending on the genetic structure of the populations. The association that is reported more frequently in the different studies is with enzymatic activity.

Micronucleus frequency is correlated with antioxidant enzyme levels in workers occupationally exposed to pesticides

Oxidative stress can cause DNA damage leading to nuclear anomalies such as micronuclei (MN). Antioxidant enzymes involved in protection against intracellular oxidative stress include glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT). Pesticide exposure induces oxidative stress and alters antioxidant defense mechanisms, including detoxification and scavenger enzymes. The aim of this study was to evaluate MN frequency in workers occupationally exposed to pesticides and their relationship with antioxidant enzyme activities. A cross-sectional study was conducted in 201 individuals, some of whom were dedicated to the spraying of pesticides. The cytokinesis-block micronucleus (CBMN) assay was conducted, and the activities of GPx, GR, SOD, and CAT were determined. The geometric mean (GM) of MN was 5.4 (1-26 MN). The GM for the antioxidant enzymes was 198.68 U/mL for GPx, 38.96 U/g Hb for GR, 94.78 U/mL for SOD, and 69.77 U/g Hb for CAT. There was a lower MN frequency in males than that in females, and a higher nuclear index. In addition, age affected MN frequency. There was a negative correlation between MN frequency and GPx activity, but a positive one between MN frequency and GR activity. These findings suggest the involvement of GPx in MN frequency.

Oxidative stress and genetic damage among workers exposed primarily to organophosphate and pyrethroid pesticides

The indiscriminate use of pesticides in agriculture and public health campaigns has been associated with an increase of oxidative stress and DNA damage, resulting in health outcomes. Some defense mechanisms against free radical-induced oxidative damage include the antioxidant enzyme systems. The aim of this study was to determine the levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and the relationship of antioxidant enzyme levels with DNA damage among sprayers (workers) occupationally exposed to pesticides. The determinations of MDA and antioxidant enzymes were performed spectrophotometrically. The genotoxic effects were evaluated using the comet assay. The results showed a marginally significant decrease in SOD and CAT activities in the high exposure group compared to the control group. For MDA, statistically significant differences were found among people working long term vs. those working temporarily (P = 0.02) as sprayers. In the moderate exposure group, a positive correlation was observed between MDA levels and GPx activity. In the high exposure group, a negative correlation was observed between GR and CAT activities, and between MDA levels and GPx activities. Furthermore, in the high exposure group, a positive correlation between DNA damage parameters and MDA levels was observed. The results suggest an important role of antioxidant enzymes for the protection of DNA damage caused by occupational exposure to pesticides.

Transcriptional regulation of human Paraoxonase 1 by nuclear receptors

Paraoxonase 1 (PON1) is a calcium-dependent lactonase synthesized primarily in the liver and secreted into the plasma, where it is associates with high density lipoproteins (HDL). PON1 acts as antioxidant preventing low-density lipoprotein (LDL) oxidation, a process considered critical in the initiation and progression of atherosclerosis. Additionally, PON1 hydrolyzes and detoxifies some toxic metabolites of organophosphorus compounds (OPs). Thus, PON1 activity and expression levels are important for determining susceptibility to OPs intoxication and risk of developing diseases related to inflammation and oxidative stress. Increasing evidence has demonstrated the modulation of PON1 expression by many factors is due to interaction with nuclear receptors (NRs). Here, we briefly review the studies in this area and discuss the role of nuclear receptors in the regulation of PON1 expression, as well as how understanding these mechanisms may allow us to manipulate PON1 levels to improve drug efficacy and treat disease.

Downregulation of human paraoxonase 1 (PON1) by organophosphate pesticides in HepG2 cells

Paraoxonase 1 (PON1) is a calcium-dependent esterase synthesized primarily in the liver and secreted into the plasma where it is associated with high-density lipoproteins (HDL). PON1 hydrolyzes and detoxifies some toxic metabolites of organophosphorus compounds (OPs) such as methyl parathion and chlorpyrifos. Thus, PON1 activity and expression levels are important for determining susceptibility against OPs poisoning. Some studies have demonstrated that OPs can modulate gene expression through interactions with nuclear receptors. In this study, we evaluated the effects of methyl parathion and chlorpyrifos on the modulation of PON1 in Human Hepatocellular Carcinoma (HepG2) cells by real-time PCR, PON1 activity assay, and western blot. The results showed that the treatments with methyl parathion and chlorpyrifos decreased PON1 mRNA and immunoreactive protein and increased inflammatory cytokines in HepG2 cells. The effects of methyl parathion and chlorpyrifos on the downregulation of PON1 gene expression in HepG2 cells may provide evidence of OPs cytotoxicity related to oxidative stress and an inflammatory response. A decrease in the expression of the PON1 gene may increase the susceptibility to OPs intoxication and the risk of diseases related to inflammation and oxidative stress. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 490-500, 2017.

Human papilloma virus genotypes in women from Nayarit, Mexico, with squamous intraepithelial lesions and cervical cancer

OBJECTIVE

In Mexico cervical cancer (CC) is the most common cause of death from neoplasia in women. Study aimed to analyze the current distribution of Human papillomavirus (HPV) types in women from Nayarit, Mexico, with Squamous intraepithelial lesions (SIL) and Cervical cancer (CC).

METHODOLOGY

Between January 2011 and July 2013, cervical samples were collected from female residents of the Mexican state of Nayarit and were analyzed by means of a LINEAR ARRAY® HPV genotyping test. Data analyses were performed using Stata ver. 8.0 statistical software.

RESULTS

Of the samples analyzed, 91.2%, HPV DNA was detected. Of these positive samples, 82% were High-risk (HR) viral types. The most prevalent HPV genotypes identified were 16, 58, 31, 18, and 70. Forty two percent of participants had a single infection, while 23 and 26% of participants were infected with two or more HPV genotypes, respectively. HPV 16 was the most prevalent genotype identified and was frequently present as a co-infection with HPV types 18, 51, 52, 59, 66, or 70.

CONCLUSION

Women <20 years of age were most often infected with HPV, and the HPV Quadrivalent vaccine (types 16, 18, 6, and 11), currently available in Mexico, no confers protection against a subset of the HPV genotypes identified in the present study (58, 31, 70, and 35). Thus, it is important evaluate the geographical distribution of specific HPV genotypes in all health of center across Mexico in order to implement a successful vaccination program and to diagnose CC in its early stages.

Effects of diazinon on the lymphocytic cholinergic system of Nile tilapia fish (Oreochromis niloticus)

Fish rearing under intensive farming conditions can be easily disturbed by pesticides, substances that have immunotoxic properties and may predispose to infections. Organophosphorus pesticides (OPs) are widely used in agricultural activities; however, the mechanism of immunotoxicity of these substances is unclear. The aim of this study was to evaluate the effect of diazinon pesticides (OPs) on the cholinergic system of immune cells as a possible target of OP immunotoxicity. We evaluated ACh levels and cholinergic (nicotinic and muscarinic) receptor concentration. Additionally, AChE activity was evaluated in mononuclear cells of Nile tilapia (Oreochromis niloticus), a freshwater fish mostly cultivated in tropical regions around the world. The obtained results indicate that acute exposure to diazinon induces an increase in ACh concentration and a decrease in nAChR and mAChR concentrations and AChE activity in fish immune cells, This suggests that the non-neuronal lymphocytic cholinergic system may be the main target in the mechanism of OP immunotoxicity. This study contributes to the understanding of the mechanisms of immunotoxicity of pollutants and may help to take actions for animal health improvement.

[Initial surgical management of squamous carcinoma of the vulva]

Vulvar cancer accounts for approximately 4% of gynecological malignancies. At the Instituto Nacional de Cancerologia in Mexico it occupies the fourth place. The purpose of this study is to assess the management of squamous carcinoma of the vulva with initial surgical treatment. It is a descriptive retrospective, observational study, from January 1, 2002 to December 31, 2012. Twenty-seven patients, clinical stages I, II, or III, initial surgical management, with at least one year of follow-up were included. In 51.85% a partial vulvectomy was performed and in 40.74% a wide excision; 66.66% underwent inguinofemoral dissection. Recurrence occurred in 25.91% of cases and the overall survival at 10 years was 63%. It is concluded that with invasion of up to 1 mm of lymph node, affection is 0%; with invasion of 1 mm and up to 5 mm this increases to 25%; an invasion of more than 5 mm implies up to 45%. Recurrence in our study was primarily distant, necessitating long-term monitoring with emphasis on symptoms to request imaging studies when suspected. Adjuvant therapy should be offered to patients with positive nodes, close or positive margins, and tumors larger than 4 cm.

Cytostatic and genotoxic effect of temephos in human lymphocytes and HepG2 cells

Temephos is an organophosphorus pesticide that is used in control campaigns against Aedes aegypti mosquitoes, which transmit dengue. In spite of the widespread use of temephos, few studies have examined its genotoxic potential. The aim of this study was to evaluate the cytotoxic, cytostatic and genotoxic effects of temephos in human lymphocytes and hepatoma cells (HepG2). The cytotoxicity was evaluated with simultaneous staining (FDA/EtBr). The cytostatic and genotoxic effects were evaluated using comet assays and the micronucleus technique. We found that temephos was not cytotoxic in either lymphocytes or HepG2 cells. Regarding the cytostatic effect in human lymphocytes, temephos (10 μM) caused a significant decrease in the percentage of binucleated cells and in the nuclear division index as well as an increase in the apoptotic cell frequency, which was not the case for HepG2 cells. The comet assay showed that temephos increased the DNA damage levels in human lymphocytes, but it did not increase the MN frequency. In contrast, in HepG2 cells, temephos increased the tail length, tail moment and MN frequency in HepG2 cells compared to control cells. In conclusion, temephos causes stable DNA damage in HepG2 cells but not in human lymphocytes. These findings suggest the importance of temephos biotransformation in its genotoxic effect.

Morbidity of breast cancer and cervico-uterine cancer in women from the occidental region of Mexico

BACKGROUND

The incidences of breast cancer (BC) and cervico-uterine cancer (CC) vary widely from country to country. In Mexico, BC mortality has doubled in the last 20 years to become the second leading cause of death for women aged 30 to 54 years. CC is the most common cause of death from neoplasia in women over 25 years old. In 2006, the state of Nayarit had one of the highest mortality rates for these types of cancers in Mexico.

OBJECTIVE

To analyze and characterize the current demographics and morbidities associated with BC and CC in the state of Nayarit.

MATERIAL AND METHODS

In this retrospective study, the clinical histories of patients who were diagnosed with BC or CC at the State Cancer Center from January 2006 to December 2010 were analyzed.

RESULTS

A total of 406 patients with BC and 328 patients with CC were registered. The most common clinical stage for both cancer types was IIB. The municipalities of San Pedro Lagunillas and El Nayar presented the highest prevalences of BC and CC, respectively.

CONCLUISION

Our results suggest that women living in poorer and more marginalized regions have a higher possibility of developing BC and CC. Because BC and CC are preventable and treatable in their early stages, demographic information from population records for these cancers is helpful in determining the incidence rates and patterns and improving decision-making processes.

AKRs expression in peripheral blood lymphocytes from smokers: the role of body mass index

Aldo-keto reductases (AKRs) metabolize a wide range of substrates, including polycyclic aromatic hydrocarbons (PAHs), generating metabolites (o-quinones) and reactive oxygen species (ROS), which are capable of initiating and promoting carcinogenesis. Exposure to PAHs, their metabolites, and ROS further increase AKRs isoform expression that may amplify oxidative damage. Human AKR enzymes are highly polymorphic, and allelic variants may contribute to different AKRs expression in individuals. Despite the importance of AKRs in PAHs metabolism, there are no studies that evaluate, in general human populations, the effect of PAHs on AKRs expression in peripheral blood lymphocytes (PBLs). The aim of this study was to determine the effect of tobacco smoke exposure, and AKR1A1*2 and AKR1C3*2 polymorphisms, on AKR1A1 and AKR1C1-AKR1C3 messenger RNA (mRNA) levels in PBLs from smokers. In the smoker group, there is a statistically significant positive association between AKR1A1, AKR1C1, and AKR1C3 mRNA induction and urine cotinine levels in individuals with a body mass index (BMI) less than 25. However, AKR1A1*2 and AKR1C3*2 alleles did not influence AKR1A1 and AKR1C1-AKR1C3 mRNA levels. These results suggest that AKRs induction by PAHs in smokers' PBLs is associated with BMI; therefore, the role of adipose tissue accumulation in PAHs' effects needs further investigation.

Evaluation of pollution in Camichin estuary (Mexico): pro-oxidant and antioxidant response in oyster (Crassostrea corteziensis)

The physiological system of molluscs, particularly pro-oxidant and antioxidant mechanisms, could be altered by pollutants and induce disturbance on health status and productive parameters of aquatic organisms, such as oyster. Therefore, the aim of this study was to evaluate the chemical contamination in water (total metals and polycyclic aromatic hydrocarbons) and oxidative stress parameters in oysters (Crassostrea corteziensis) in Camichin estuary, located in Mexican Tropical Pacific. The results obtained showed the presence of arsenic, lead and zinc, as well as naphthalene, pyrene and benzo[a]pyrene in concentrations relatively higher than criteria established by local and international guidelines. Regarding the biomarkers of oxidative stress response (H2O2 and O2 concentration, catalase activity, lipid peroxidation, and hydroperoxide concentration), differences between oyster from estuary and control group were significant. These results indicate that these pollutants could be related with oxidative stress detected in oyster.

Phytoremediatory effect and growth of two species of Ocimum in endosulfan polluted soil

Endosulfan is a hazardous organochlorine pesticide banned or restricted in several countries. However, it has been found in the environment and in animal samples. To study a potential way to bioremediate soils contaminated with this pesticide, two plant species of the genus Ocimum were studied: Ocimum basilicum L. and Ocimum minimum L., since they are economically feasible and well adapted to the climatic conditions of the Nayarit zone (Mexican pacific coast). Young plants were transplanted into soil experimentally polluted with endosulfan. Growth of both species was not affected by endosulfan, the plants grew, flourished, and produced seeds; 30 days later, endosulfan concentration was lower in the soil with O. basilicum than in the soil without plants. On day 90, no differences in endosulfan concentrations were found between soil with or without O. minimum. At day 1, plants in the polluted soil showed lipoperoxidation, as measured by thiobarbituric acid-reactive species (TBARS). Interestingly, a higher TBARS value was observed at day 3 in transplanted plants as compared to non-transplanted plants. In conclusion, both species can endure endosulfan pollution (as high as 1 g kg(-1)) in soils. O. basilicum seems to be an adequate candidate for bioremediation of soils polluted with endosulfan.

Acetylcholinesterase and metallothionein in oysters (Crassostrea corteziensis) from a subtropical Mexican Pacific estuary

Substantial efforts have been devoted to developing and applying biomarkers for ecological risk assessment. Bivalve mollusks, such as mussels and oysters, are commonly used in environmental monitoring programs because of their wide geographical distribution, great sensitivity to environmental pollutants, and ability to accumulate anthropogenically derived chemicals at a high rate. Acetylcholinesterase (AChE) activity and metallothionein (MT's) content are representative specific biomarkers that indicate the presence of anticholinesterasic compounds (like organophosphorus and carbamate pesticides) and metals, respectively. The aim of this study was to evaluate AChE activity and MT's content in Crassostrea corteziensis from Boca de Camichín estuary. The results obtained here showed that AChE activity was 65% lower in oysters from Boca de Camichín than in control organisms. In contrast, MT's content in collected organisms was not statistically different from that in control organisms. AChE activity and MT's content in oysters could be used as early biomarkers of effects and exposure to pesticides and heavy metals, respectively, in aquatic environments.

Genetic damage caused by methyl–parathion in mouse spermatozoa is related to oxidative stress

Organophosphorous (OP) pesticides are considered genotoxic mainly to somatic cells, but results are not conclusive. Few studies have reported OP alterations on sperm chromatin and DNA, and oxidative stress has been related to their toxicity. Sperm cells are very sensitive to oxidative damage which has been associated with reproductive dysfunctions. We evaluated the effects of methyl-parathion (Me-Pa; a widely used OP) on sperm DNA, exploring the sensitive stage(s) of spermatogenesis and the relationship with oxidative stress. Male mice (10-12-weeks old) were administered Me-Pa (3-20 mg/kg bw/i.p.) and euthanized at 7- or 28-days post-treatment. Mature spermatozoa were obtained and evaluated for chromatin structure through SCSA (Sperm Chromatin Structure Assay; DNA Fragmentation Index parameters: Mean DFI and DFI%) and chromomycin-A(3) (CMA(3))-staining, for DNA damage through in situ-nick translation (NT-positive) and for oxidative stress through lipid peroxidation (LPO; malondialdehyde production). At 7-days post-treatment (mature spermatozoa when Me-Pa exposure), dose-dependent alterations in chromatin structure (Mean DFI and CMA(3)-staining) were observed, as well as increased DNA damage, from 2-5-fold in DFI% and NT-positive cells. Chromatin alterations and DNA damage were also observed at 28-days post-treatment (cells at meiosis at the time of exposure); suggesting that the damage induced in spermatocytes was not repaired. Positive correlations were observed between LPO and sperm DNA-related parameters. These data suggest that oxidative stress is related to Me-Pa alterations on sperm DNA integrity and cells at meiosis (28-days post-treatment) and epididymal maturation (7-days post-treatment) are Me-Pa targets. These findings suggest a potential risk of Me-Pa to the offspring after transmission.

Genetic polymorphisms and activity of PON1 in a Mexican population

Human paraoxonase (PON1) plays a role in detoxification of organophosphorus (OP) compounds by hydrolyzing the bioactive oxons, and in reducing oxidative low-density lipoproteins, which may protect against atherosclerosis. Some PON1 polymorphisms have been found to be responsible for variations in catalytic activity and expression and have been associated with susceptibility to OP poisoning and vascular diseases. Both situations are of public health relevance in Mexico. Therefore, the aim of this study was to evaluate PON1 phenotype and the frequencies of polymorphisms PON1 -162, -108, 55, and 192 in a Mexican population. The studied population consisted of unrelated individuals (n = 214) of either gender, 18-52 years old. Serum PON1 activity was assayed using phenylacetate and paraoxon as substrates. PON1 variants, -162, 55, and 192, were determined by real-time PCR using the TaqMan System, and PON1 -108 genotype by PCR-RFLP. We found a wide interindividual variability of PON1 activity with a unimodal distribution; the range of enzymatic activity toward phenylacetate was 84.72 to 422.0 U/mL, and 88.37 to 1645.6 U/L toward paraoxon. All four PON1 polymorphisms showed strong linkage disequilibrium (D% >90). PON1 polymorphisms -108, 55, and 192 were independently associated with arylesterase activity; whereas the activity toward paraoxon was related only with PON1 192 polymorphism, suggesting that this polymorphism is determinant to infer PON1 activity. A better understanding of the phenotype and genotypes of PON1 in Mexican populations will facilitate further epidemiological studies involving PON1 variability in OP poisoning and in the development of atherosclerosis.