Oral exfoliative cytology – A technical appraisal in oral diseases

Oral exfoliative cytology is one of the easy, simple, economical and non-cumbersome diagnostic adjunct. It involves examining the exfoliated buccal cells for alterations in cellular and nuclear features. It offers the advantage of being useful in less resource setting areas. Though associated with many false results, the newer technological advancements have proven its diagnostic efficiency. Oral exfoliative cytology can readily be used as adjunct to disease diagnosis, however, it cannot replace biopsy.

Impact of Prematurity on the Buccal Epithelial Cells of the Neonates via Wnt/Beta-Catenin Signaling Pathway and Apoptosis

Objective Understanding the reflections of prematurity is necessary for the management of neonatal complications. We focused on the impact of prematurity and related “maternal risk factors/obstetric complications” on buccal cells of the neonates via evaluation of the Wnt/β-catenin signaling pathway and apoptosis. Study Design This study consisted of “early preterm neonates (EPN) (≤34th gestational week [gw]) (n = 36),” “late preterm neonates (LPN) (34th– < 37th gw) (n = 46),” and “term neonates (control) (≥37th gw) (n = 56).” Cohort was also subclassified according to the presence of maternal risk factors, obstetric complications, and neonatal complications. Wnt/β-catenin signaling and caspase-3 activation pathways were studied immunocytochemically. Results Wnt/β-catenin signaling positivity was statistically more frequent at buccal smears of the EPN and LPN groups compared with controls (p < 0.001). The cutoff for gestational age at delivery in receiver operating characteristic curve with the best balance of sensitivity (67.4%) and specificity (67.3%) was 35.8th gw for determining the reduction of Wnt/β-catenin signaling positivity (p < 0.001). The study demonstrated that obstetric complications significantly affected the activity of signaling, while maternal risk factors do not have any effect on Wnt/β-catenin signaling pathway (p = 0.003 and p = 0.828, respectively). This study also demonstrated a significant relationship between Wnt/β-catenin signaling pathway and the presence of neonatal complications (p = 0.015). Conclusion Dynamic characteristics of buccal cells are influenced by prematurity and related obstetric and neonatal problems. Buccal smear is a good tool to investigate the impact of prematurity and obstetric problems on perinatal outcome. Key Points

Comparison of Telomere Length Between Buccal Cells and Blood Cells

Background Telomere length (TL) in blood has been extensively studied as a biomarker of aging and aging-associated disease. TL in blood cells is commonly used as a proxy for TL in other tissue types. The source of DNA of adequate quality and quantity is an important consideration in telomere length analysis. Compared to blood cells, buccal cells easy for genomic DNA preparation would facilitate the rapid and reliable telomere length analysis. However, the feasibility of buccal cells for TL analysis remains yet unestablished. Methods A total of 52 participants ranged in age from 18 to 80 years including 24 males and 28 females were included in this study. Both buccal and blood samples were taken at the same time by using buccal cell swabs and fingertip stick from each participant. Relative telomere length (RTL) was analyzed using the quantitative real-time polymerase chain reaction (qPCR) method. Results The results indicate that there is a strong positive correlation between buccal RTL and blood RTL and negative correlation between both buccal RTL and blood RTL with age. Conclusion The validity of sampling using buccal cell swabs provides simple operation and good reproducibility for telomere length analysis, which overcomes the discomfort and risk of infection caused by blood sampling.

Epigenome association study for DNA methylation biomarkers in buccal and monocyte cells for female rheumatoid arthritis

Genetics (i.e., mutations) has been assumed to be the major factor in rheumatoid arthritis (RA) etiology, but accounts for a minority of the variance in disease risk for RA. In contrast to genetics, the environment can have dramatic impacts on epigenetics that associate with disease etiology. The current study used buccal cells and purified blood monocytes from two different clinical cohorts involving Caucasian or African American female populations with or without arthritis. The differential DNA methylation regions (DMRs) between the control and RA populations were identified with an epigenome-wide association study. The DMRs (i.e., epimutations) identified in the buccal cells and monocytes were found to be distinct. The DMR associated genes were identified and many have previously been shown to be associated with arthritis. Observations demonstrate DNA methylation epimutation RA biomarkers are cell type specific and similar findings were observed with the two racial background populations. Rheumatoid arthritis susceptibility epigenetic diagnosis appears feasible and may improve the clinical management of RA and allowpreventative medicine considerations.

Genome-Wide Analysis of DNA Methylation in Buccal Cells of Children Conceived through IVF and ICSI

Early life periconceptional exposures during assisted reproductive technology (ART) procedures could alter the DNA methylation profiles of ART children, notably in imprinted genes and repetitive elements. At the genome scale, DNA methylation differences have been reported in ART conceptions at birth, but it is still unclear if those differences remain at childhood. Here, we performed an epigenome-wide DNA methylation association study using Illumina InfiniumEPIC BeadChip to assess the effects of the mode of conception on the methylome of buccal cells from 7- to 8-year-old children (48 children conceived after ART or naturally (control, CTL)) and according to the embryo culture medium in which they were conceived. We identified 127 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) (FDR < 0.05) with low delta beta differences between the two groups (ART vs. CTL). DMPs were preferentially located inside promoter proximal regions and CpG islands and were mostly hypermethylated with ART. We highlighted that the use of distinct embryo culture medium was not associated with DNA methylation differences in childhood. Overall, we bring additional evidence that children conceived via ART display limited genome-wide DNA methylation variation compared with those conceived naturally.

Electronic waste exposure and DNA damage: a systematic review and meta-analysis

Objectives Inappropriate processing and disposal of electronic waste (e-waste) expose workers and surrounding populations to hazardous chemicals, including clastogens and aneugens. Recently, considerable literature has grown around e-waste recycling, associated chemical exposures and intermediate health outcomes, including DNA damage. Micronuclei (MN) frequency has been widely used as a biomarker to investigate DNA damage in human populations exposed to genotoxic agents. We conducted a systematic review of published studies to assess DNA damage in e-waste-exposed populations and performed a meta-analysis to evaluate the association between e-waste exposure and DNA damage. Methods This systematic review with meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement checklist. Articles published in English from January 2000 through December 2020 investigating the associations between e-waste exposure and DNA damage were retrieved from the following three major databases: MEDLINE, ProQuest, and Scopus. Studies that reported the use of MN assay as a biomarker of DNA damage were included for meta-analysis. Studies that also reported other DNA damage biomarkers such as chromosomal aberrations, comet assay biomarkers, 8-hydroxy-2′-deoxyguanosine (8-OHdG), telomere length, apoptosis rate were reported using narrative synthesis. Results A total of 20 publications were included in this review, of which seven studies were within the occupational setting, and the remaining 13 studies were ecological studies. The review found six biomarkers of DNA damage (micronuclei, comets assay parameters (tail length, % tail DNA, tail moment, and olive tail moment), 8-OHdG, telomere length, apoptosis rate and chromosomal aberrations) which were assessed using seven different biological matrices (buccal cells, blood, umbilical cord blood, placenta, urine and semen). Most studies showed elevated levels of DNA damage biomarkers among e-waste exposed populations than in control populations. The most commonly used biomarkers were micronuclei frequency (n=9) in peripheral blood lymphocytes or buccal cells and 8-OHdG (n=7) in urine. The results of the meta-analysis showed that electronic waste recycling has contributed to an increased risk of DNA damage measured using MN frequency with a pooled estimate of the standardized mean difference (SMD) of 2.30 (95% CI: 1.36, 3.24, p<0.001) based on 865 participants. Conclusions Taken together, evidence from this systematic review with meta-analysis suggest that occupational and non-occupational exposure to e-waste processing is associated with increased risk of DNA damage measured through MN assay and other types of DNA damage biomarkers. However, more studies from other developing countries in Africa, Latin America, and South Asia are needed to confirm and increase these results’ generalizability.

DNA methylation in peripheral tissues and Left-handedness

Handedness has low heritability and epigenetic mechanisms have been proposed as an etiological mechanism. To examine this hypothesis, we performed an epigenome-wide association study (EWAS) of left-handedness. In a meta-analysis of 3,914 adults of whole-blood DNA methylation, we observed that CpG sites located in proximity of handedness-associated genetic variants were more strongly associated with left-handedness than other CpG sites (P = 0.04), but did not identify any differentially methylated positions. We identified differentially methylated regions at 20q11.23 (P = 0.00004) and 2p25.1 (P = 0.03), which were less methylated in left-handed adults. In longitudinal analyses of DNA methylation in peripheral blood and buccal cells from children (N = 1,737), we observed moderately stable associations across age (correlation range [0.355–0.578]) but inconsistent across tissues (correlation range [-0.384-0.318]). We conclude that DNA methylation in peripheral tissues captures little of the variance in handedness. Future investigations should consider other more targeted sources of tissue, such as the brain.

Micronuclei and Other Nuclear Anomalies in Exfoliated Buccal Mucosa Cells in Breast Cancer

Objectives: This study designed to assess the genomic instability between healthy women and women with breast cancer by means of buccal cells micronucleus (MN) cytome assay. Methods: The current study comprised 25 healthy women and 30 breast cancer patients. The exfoliated cells of buccal mucosa were taken after each participants rinse their mouths with tap water. The micronucleated cell and nuclear anomalies were analyzed under a total magnification of X1000, 2000 cells per subjects ( patient and control group) were scored and the frequencies of nuclear anomalies including MN, binucleates (BN), Pycnotic cell, karyolysis (KL) and karyorrhexis (KR) were evaluated in exfoliated buccal mucosa cells of women with primary BC and healthy women. Results: The frequencies of micronuclei and all nuclear anomalies in buccal cells of BC patients were significantly increased compared with the controls. (For Binucleates cells only, p<0.001; in all other cases, P < 0.0001). The mean scores of micronuclei and all nuclear anomalies for the breast cancer patients were (10.66±0.3845, 6.20±0.26, 8.40±0. 22, 18.40±0. 34, 19.13 ±0.40) were significantly higher than that of healthy women). Conclusion: Elevated frequency of micronucleated cells and all nuclear anomalies in the buccal mucosa of breast cancer patients reveal the genomic instability. These findings propose that the buccal MN-cytome assay can be used to measure both genotoxic and cytotoxic effects in primary cancer patients.

Winter Air Pollution and Genotoxic Effects in Children Living in a Highly Polluted Urban Area

Air pollutants, especially PM, have been found to determine various effects on human health, including genotoxic effects. The aim of this study was to assess DNA damage with micronuclei (MN) and comet tests on buccal cells of 6–8 years old children living in an area with high air pollution. Both tests were repeated in the same children in two consecutive winters to compare the levels of DNA damage under different pollution conditions. A complete data set including lifestyle, air pollutants levels and biological sampling was available for 180 children in the two winters. A high mean MN frequency was found in both seasons, with higher value in the first (0.51 ± 0.59) than the second winter (0.40 ± 0.52), whereas DNA damage measured with comet test showed higher damage in the second versus the first winter (visual score 208.8 ± 67.1 vs. 173.2 ± 50.8). The associations between air pollutant levels (CO, NO2, SO2, benzene, O3, PM10, and PM2.5; PM0.5 and PAHs) and DNA damage were investigated at different lag times, and mainly, no significant association was found. This study on repeated measure of MN frequency and DNA damage in children’s buccal did not show an association with various air pollutants evaluated in an area with high levels of air pollution.

ANALISIS SITOGENETIK SEL EPITEL MUKOSA BUKAL PEKERJA STASIUN PENGISI BAHAN BAKAR UMUM DI KOTA YOGYAKARTA

Workers employed in petroleum station have a high-risk exposure to a wide range of toxic compounds with known mutagenic and carcinogenic potential. Cytogenetic damage might have happened if they continuously exposed to petroleum derivatives. This study aimed to analyse the cytogenetic damage in exfoliated buccal cells among petroleum station workers in Yogyakarta City. This cross-sectional study was carried out on 30 petrol station workers who are working at a different petrol station in Yogyakarta and the control group consisted of 30 healthy subjects. Examination for all subjects included frequencies of nuclear abnormalities, including pycnosis, karyorrhexis, and karyolysis. Cytological preparations were stained according to papanicolaou reaction and analyzed under light microscope for making a score for degenerative nuclear alterations (pycnosis, karyolysis and karyorrhexis). Analysis of buccal cells revealed that frequencies of pycnosis and karyorrhexis in petrol station workers were significantly higher than the control group (P<0.05). Conversely, there was no significant difference in karyolisis among groups. These findings indicate that the petrol station workers are under the risk of significant cytogenetic damage, particularly pycnosis and karyorrhexis.