Associations of phthalates with accelerated aging and the mitigating role of physical activity.

Phthalates are positioned as potential risk factors for health-related diseases. However, the effects of exposure to phthalates on accelerated aging and the potential modifications of physical activity remain unclear. A total of 2317 participants containing complete study-related information from the National Health and Nutrition Examination Survey 2007-2010 were included in the current study. We used two indicators, the Klemera-Doubal method biological age acceleration (BioAgeAccel) and phenotypic age acceleration (PhenoAgeAccel), to assess the accelerated aging status of the subjects. Multiple linear regression (single pollutant models), weighted quantile sum (WQS) regression, Quantile g-computation, and Bayesian kernel machine regression (BKMR) models were utilized to explore the associations between urinary phthalate metabolites and accelerated aging. Three groups of physical activity with different intensities were used to evaluate the modifying effects on the above associations. Results indicated that most phthalate metabolites were significantly associated with BioAgeAccel and PhenoAgeAccel, with effect values (ß) ranging from 0.16 to 0.21 and 0.16-0.37, respectively. The WQS indices were positively associated with BioAgeAccel (0.33, 95% CI: 0.11, 0.54) and PhenoAgeAccel (0.50, 95% CI: 0.19, 0.82). Quantile g-computation indicated that phthalate mixtures were associated with accelerated aging, with effect values of 0.15 (95% CI: 0.02, 0.28) for BioAgeAccel and 0.39 (95% CI: 0.12, 0.67) for PhenoAgeAccel respectively. The BKMR models indicated a significant positive association between the concentrations of urinary phthalate mixtures with the two indicators. In addition, we found that most phthalate metabolites showed the strongest effects on accelerated aging in the no physical activity group and that the effects decreased gradually with increasing levels of physical activity (P < 0.05 for trend). Similar results were also observed in the mixed exposure models (WQS and Quantile g-computation). This study indicates that phthalates exposure is associated with accelerated aging, while physical activity may be a crucial barrier against phthalates exposure-related aging.

Transcriptomics-based analysis reveals the nephrotoxic effects of triphenyltin (TPT) on SD rats by affecting RAS, AQPs and lipid metabolism.

Triphenyltin (TPT) is a class of organotin compounds that are extensively used in industry and agriculture. They have endocrine-disrupting effects and cause severe environmental contamination. Pollutants may accumulate in the kidneys and cause pathological complications. However, the mechanism of TPT's toxicological effects on the kidney remains unclear. This study aimed to investigate the toxic effects and mechanism of action of TPT exposure on renal impairment in rats. Male SD rats were divided into four groups: the Ctrl group (control group), TPT-L group (0.5 mg/kg/d), TPT-M group (1 mg/kg/d), and TPT-H group (2 mg/kg/d). After 28 days of exposure to TPT, we observed the morphology and structure of kidney tissue using HE, PASM, and Masson staining. We also detected serum biochemical indexes, performed transcriptome sequencing of rat kidney tissue using RNA-seq. Furthermore, protein expression levels were measured through immunohistochemistry and gene expression levels were determined using RT-qPCR. The study results indicated a decrease in kidney weight and relative kidney weight after 28 days of exposure to TPT. Additionally, TPT caused damage to kidney structure and function, as evidenced by HE staining, PASM staining, and serum biochemical tests. Transcriptomics identified 352 DEGs, and enrichment analyses revealed that TPT exposure primarily impacted the renin-angiotensin system (RAS). The expression levels of water channel proteins were reduced, and the expression levels of RAS and lipid metabolism-related genes (Mme, Ace, Fasn, Cyp4a8, Cpt1b and Ppard) were significantly decreased in the TPT-treated group. In summary, exposure to TPT may impair renal structure and function in rats by affecting RAS, AQPs, and lipid metabolism.

Quality of clinical practice guidelines relevant to rehabilitation of knee osteoarthritis: A systematic review.

OBJECTIVE: This systematic review summarized the rehabilitation recommendations for treating and managing knee osteoarthritis (OA) in practice guidelines and evaluated their applicability and quality using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. DATA SOURCES: PubMed, the Cochrane Library, EMBASE, CINAHL, PEDro, Guideline central, Guideline International Network and Agency for Healthcare Research and Quality (AHRQ) were used to search for relevant studies published between 1 January 2008 and 31 May 2022. METHODS: AGREE II was used to evaluate the included guidelines quality, SPSS 25.0 statistical software was used for data analysis, and the intra-group correlation coefficient value was calculated to verify the consistency between the raters. The two-way random effects model was used to calculate concordance scores, and each domain's total scores were calculated. Additionally, the median and interquartile range for domain and total scores were calculated. RESULTS: Twenty-four guidelines recommending knee OA rehabilitation were included. Inter-rater consistency evaluation ranged from 0.62 to 0.90. The domains where the guideline's overall and rehabilitation parts scored highest and lowest were scope and purpose (domain 1) and applicability (domain 5), respectively. The highly recommended rehabilitation opinions included aerobic exercise programs (21/24), weight control (16/24), self-education and management (16/24), gait/walking aids (7/24), and tai chi (6/24). However, the orthopedic insole and hot/cold therapy roles remain controversial. CONCLUSION: The clinical practice guidelines' overall quality for knee OA rehabilitation is good; however, the applicability is slightly poor. Therefore, we should improve the promoting factors and hindering factors, guideline application recommendations, tools, and resources when developing relevant guidelines.

Comparative Analysis of Five Correction Methods for Thyroid Volume by Ultrasound and Their Recommended Reference Values in Chinese Children Aged 8-10 Years.

Considering the influence of body's growth and development on thyroid volume (TVOL), whether five existed corrected methods could be applied to correct TVOL remains unclear, in terms of Chinese children's increased growth and development trends. This study aimed to compare the applicability of five correction methods for TVOL: Body Surface Area corrected Volume (BSAV), Body Mass Indicator corrected Volume (BMIV), Weight and Height corrected Volume Indicator (WHVI), Height corrected Volume Indicator 1 (HVI1) and Height corrected Volume Indicator 2 (HVI2); to establish the reference values for correction methods. The data of Iodine Nutrition and Thyroid Function Survey was used to analyse the differences in TVOL between normal and abnormal thyroid function children. Data of National Iodine Deficiency Disorders Survey were used to compare five correction methods and to establish their reference values. The median urinary iodine concentration of children surveyed were 256.1µg/L in 2009 and 192.6µg/L in 2019, respectively. No significant difference was found in TVOL and thyroid goitre rate between children with normal and abnormal thyroid function. In the determination of goitre, HVI1, HVI2, BSAV and BMIV all showed high agreement with TVOL, while the area under the ROC curve (AUC) of WHVI was relatively low for children aged 8(AUC=0.8993) and 9(AUC=0.8866). Most differences of TVOL between light and heavy weight, short and tall height children can be eliminated by BSAV correction. BSAV was the best method of TVOL correction in this research. Reference values were established for corrected thyroid volumes in Chinese children aged 8-10 years by sex.

Prognostic role of Wnt and Fzd gene families in acute myeloid leukaemia.

Wnt-Fzd signalling pathway plays a critical role in acute myeloid leukaemia (AML) progression and oncogenicity. There is no study to investigate the prognostic value of Wnt and Fzd gene families in AML. Our study screened 84 AML patients receiving chemotherapy only and 71 also undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT) from the Cancer Genome Atlas (TCGA) database. We found that some Wnt and Fzd genes had significant positive correlations. The expression levels of Fzd gene family were independent of survival in AML patients. In the chemotherapy group, AML patients with high Wnt2B or Wnt11 expression had significantly shorter event-free survival (EFS) and overall survival (OS); high Wnt10A expressers had significantly longer OS than the low expressers (all P < .05), whereas, in the allo-HSCT group, the expression levels of Wnt gene family were independent of survival. We further found that high expression of Wnt10A and Wnt11 had independent prognostic value, and the patients with high Wnt10A and low Wnt11 expression had the longest EFS and OS in the chemotherapy group. Pathway enrichment analysis showed that genes related to Wnt10A, Wnt11 and Wnt 2B were mainly enriched in 'cell morphogenesis involved in differentiation', 'haematopoietic cell lineage', 'platelet activation, signalling and aggregation' and 'mitochondrial RNA metabolic process' signalling pathways. Our results indicate that high Wnt2B and Wnt11 expression predict poor prognosis, and high Wnt10A expression predicts favourable prognosis in AML, but their prognostic effects could be neutralized by allo-HSCT. Combined Wnt10A and Wnt11 may be a novel prognostic marker in AML.

The establishment of a prognostic scoring model based on the new tumor immune microenvironment classification in acute myeloid leukemia.

BACKGROUND: The high degree of heterogeneity brought great challenges to the diagnosis and treatment of acute myeloid leukemia (AML). Although several different AML prognostic scoring models have been proposed to assess the prognosis of patients, the accuracy still needs to be improved. As important components of the tumor microenvironment, immune cells played important roles in the physiological functions of tumors and had certain research value. Therefore, whether the tumor immune microenvironment (TIME) can be used to assess the prognosis of AML aroused our great interest. METHODS: The patients' gene expression profile from 7 GEO databases was normalized after removing the batch effect. TIME cell components were explored through Xcell tools and then hierarchically clustered to establish TIME classification. Subsequently, a prognostic model was established by Lasso-Cox. Multiple GEO databases and the Cancer Genome Atlas dataset were employed to validate the prognostic performance of the model. Receiver operating characteristic (ROC) and the concordance index (C-index) were utilized to assess the prognostic efficacy. RESULTS: After analyzing the composition of TIME cells in AML, we found infiltration of ten types of cells with prognostic significance. Then using hierarchical clustering methods, we established a TIME classification system, which clustered all patients into three groups with distinct prognostic characteristics. Using the differential genes between the first and third groups in the TIME classification, we constructed a 121-gene prognostic model. The model successfully divided 1229 patients into the low and high groups which had obvious differences in prognosis. The high group with shorter overall survival had more patients older than 60 years and more poor-risk patients (both P< 0.001). Besides, the model can perform well in multiple datasets and could further stratify the cytogenetically normal AML patients and intermediate-risk AML population. Compared with the European Leukemia Net Risk Stratification System and other AML prognostic models, our model had the highest C-index and the largest AUC of the ROC curve, which demonstrated that our model had the best prognostic efficacy. CONCLUSION: A prognostic model for AML based on the TIME classification was constructed in our study, which may provide a new strategy for precision treatment in AML.

Increased expression of IFI16 predicts adverse prognosis in multiple myeloma.

Multiple myeloma (MM) is a malignancy of terminally differentiated plasma cells and does not have sufficient prognostic indicators. Interferon gamma inducible protein 16 (IFI16) plays a crucial role in B-cell differentiation. Several studies have shown that IFI16 predicted prognosis in many cancers. However, the relationship between MM prognosis and IFI16 expression has not been studied. In our study, we analyzed the prognostic role of IFI16 expression and explored the possible mechanism in MM progression by using 4498 myeloma patients and 52 healthy donors from 13 independent gene expression omnibus (GEO) datasets. The IFI16 expression increased with myeloma progression, ISS stage, 1q21 amplification, and relapse (all P < 0.01). MM patients with higher IFI16 expression had shorter survival in six datasets (all P < 0.05). Furthermore, multivariate analysis indicated that enhanced IFI16 expression was an independent poor prognostic factor for EFS and OS (P = 0.007, 0.009, respectively). And PPI, GO, KEGG, and GSEA also confirmed that IFI16 promoted MM progression by participating in tumor-related pathways. In conclusion, our study confirmed that IFI16 was a poor prognostic biomarker in MM.

Up-regulation of DDIT4 predicts poor prognosis in acute myeloid leukaemia.

The mammalian target of rapamycin (mTOR) inhibitor, DNA damage inducible transcript 4 (DDIT4), has inducible expression in response to various cellular stresses. In multiple malignancies, studies have shown that DDIT4 participates in tumorigenesis and impacts patient survival. We aimed to study the prognostic value of DDIT4 in acute myeloid leukaemia (AML), which is currently unclear. Firstly, The Cancer Genome Atlas was screened for AML patients with complete clinical characteristics and DDIT4 expression data. A total of 155 patients were included and stratified according to the treatment modality and the median DDIT4 expression levels. High DDIT4 expressers had shorter overall survival (OS) and event-free survival (EFS) than the low expressers among the chemotherapy-only group (all P < .001); EFS and OS were similar in the high and low DDIT4 expressers of the allogeneic haematopoietic stem cell transplantation (allo-HSCT) group. Furthermore, in the DDIT4high group, patients treated with allo-HSCT had longer EFS and OS than those who received chemotherapy alone (all P < .01). In the DDIT4low group, OS and EFS were similar in different treatment groups. Secondly, we analysed two other cytogenetically normal AML (CN-AML) cohorts derived from the Gene Expression Omnibus database, which confirmed that high DDIT4 expression was associated with poorer survival. Gene Ontology (GO) enrichment analysis showed that the genes related to DDIT4 expression were mainly concentrated in the acute and chronic myeloid leukaemia signalling pathways. Collectively, our study indicates that high DDIT4 expression may serve as a poor prognostic factor for AML, but its prognostic effects could be outweighed by allo-HSCT.

Prognostic role of SCAMP family in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a malignant disease of myeloid hematopoietic stem or progenitor cells characterized by abnormal proliferation of primary and immature myeloid cells in bone marrow and peripheral blood. Gene mutation and expression profiles can be used as prognosis predictors for different prognostic subgroups. Secretory carrier-associated membrane proteins (SCAMPs) are a multigenic family with five members and act as cell surface vectors in the post-Golgi recycling pathways in mammals. Nevertheless, the prognostic and clinical influence of SCAMP family has hardly ever been illustrated in AML. In our study, expression patterns of SCAMP family (SCAMP1-5) were analyzed in 155 AML patients which were extracted from the Cancer Genome Atlas database. In chemotherapy, only subgroup, higher SCAMP1 level was significantly associated with longer EFS and OS (all P = 0.002), and SCAMP1 was confirmed to be an independent favorable factor in un-transplanted patients by Multivariate analysis (all P < 0.05). Nevertheless, in the allogeneic hematopoietic stem cell transplantation (allo-HSCT) treatment subgroup, none of the SCAMP genes had any effect on the clinical survival. Our study found that high expression level of SCAMP1 is a favorable prognostic factor in AML, but allo-HSCT may neutralize its prognostic effect.

High expression of chaperonin-containing TCP1 subunit 3 may induce dismal prognosis in multiple myeloma.

The prognosis role of CCT3 in MM and the possible pathways it involved were studied in our research. By analyzing ten independent datasets (including 48 healthy donors, 2220 MM, 73 MGUS, and 6 PCL), CCT3 was found to express higher in MM than healthy donors, and the expression level was gradually increased from MGUS, SMM, MM to PCL (all P < 0.01). By analyzing three independent datasets (GSE24080, GSE2658, and GSE4204), we found that CCT3 was a significant indicator of poor prognosis (all P < 0.01). KEGG and GSEA analysis showed that CCT3 expression was associated with JAK-STAT3 pathway, Hippo signaling pathway, and WNT signaling pathway. In addition, different expressed genes analysis revealed MYC, which was one of the downstream genes regulated by JAK-STAT3 pathway, was upregulated in MM. This confirms that JAK-STAT3 signaling pathway may promote the progress of disease which was regulated by CCT3 expression. Our study revealed that CCT3 may play a supporting role at the diagnosis of myeloid, and high expression of CCT3 suggested poor prognosis in MM. CCT3 expression may promote the progression of MM mainly by regulating MYC through JAK-STAT3 signaling pathway.

CTRP3 Activates the AMPK/SIRT1-PGC-1α Pathway to Protect Mitochondrial Biogenesis and Functions in Cerebral Ischemic Stroke.

C1q/tumor necrosis factor-related protein-3 (CTRP3) had shown its angiogenesis and enhancement of mitochondrial biogenesis properties in the treatment of myocardial infarction, but its potential roles in cerebral ischemic stroke had not been fully understood. This study aimed to clarify the underlying mechanism of how CTRP3 regulated mitochondrial functions in hippocampal neuronal cells (HPPNCs) after oxygen-glucose deprivation (OGD)/reoxygenation (R) treatment. Results showed that impeded CTRP3 expression and weakened viability were detected in OGD/R treated HPPNCs. CTRP3 showed its ability to enhance the viability and inhibited apoptosis of HPPNCs after OGD/R treatment and it could also promote the mitochondrial biogenesis and physiological functions. Silencing of PGC-1α partially abolished the protective function of CTRP3 on mitochondria and CTRP3 mediated the expression of PGC-1α via the AMPK/SIRT1-PGC-1α pathway. These findings provided information that CTRP3 prevented mitochondria from OGD/R injury through activating the AMPK/SIRT1-PGC-1α pathway. Our study suggested that CTRP3 might have the potential to become an emerging protective agent applied in the reperfusion treatment of ischemic stroke.

Long term impact of surfactants & polymers on the colloidal stability, aggregation and dissolution of silver nanoparticles.

Cetyl trimethyl ammonium bromide (CTAB), Tween 20, polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG) are among the commonly used surfactants and polymers to stabilize silver nanoparticles (AgNPs). However, their interactions with AgNPs are different. The impact of these surfactants and polymers on the colloidal stability of freshly synthesized uncoated AgNPs was evaluated through a series of long-term experiments and analyzed in terms of their physical and chemical behavior. The cationic surfactant, CTAB was able to produce a mono modal particle size distribution in a prolonged period without affecting the dissolution. In the presence of Tween 20, a non-ionic surfactant, dissolution was promoted in the long run and the particles were preserved with minimal aggregation. In the presence of the polymers, PVP and PEG, the particle structure was not affected even though dissolution was observed. This study presents important insights on the interactions of AgNPs with surfactants and polymers, which could significantly affect the transformations and fate of AgNPs in the aquatic environment.

Peyer's patches-derived CD11b+ B cells recruit regulatory T cells through CXCL9 in dextran sulphate sodium-induced colitis.

Regulatory T (Treg) cells play an essential role in the maintenance of intestinal homeostasis. In Peyer's patches (PPs), which comprise the most important IgA induction site in the gut-associated lymphoid tissue, Treg cells promote IgA isotype switching. However, the mechanisms underlying their entry into PPs and isotype switching facilitation in activated B cells remain unknown. This study, based on the dextran sulphate sodium (DSS)-induced colitis model, revealed that Treg cells are significantly increased in PPs, along with CD11b+ B-cell induction. Immunofluorescence staining showed that infiltrated Treg cells were located around CD11b+ B cells and produced transforming growth factor-ß, thereby inducing IgA+ B cells. Furthermore, in vivo and in vitro studies revealed that CD11b+ B cells in PPs had the capacity to recruit Treg cells into PPs rather than promoting their proliferation. Finally, we found that Treg cell recruitment was mediated by the chemokine CXCL9 derived from CD11b+ B cells in PPs. These findings demonstrate that CD11b+ B cells induced in PPs during colitis actively recruit Treg cells to accomplish IgA isotype switch in a CXCL9-dependent manner.

Subcellular Relocalization and Positive Selection Play Key Roles in the Retention of Duplicate Genes of Populus Class III Peroxidase Family.

Gene duplication is the primary source of new genes and novel functions. Over the course of evolution, many duplicate genes lose their function and are eventually removed by deletion. However, some duplicates have persisted and evolved diverse functions. A particular challenge is to understand how this diversity arises and whether positive selection plays a role. In this study, we reconstructed the evolutionary history of the class III peroxidase (PRX) genes from the Populus trichocarpa genome. PRXs are plant-specific enzymes that play important roles in cell wall metabolism and in response to biotic and abiotic stresses. We found that two large tandem-arrayed clusters of PRXs evolved from an ancestral cell wall type PRX to vacuole type, followed by tandem duplications and subsequent functional specification. Substitution models identified seven positively selected sites in the vacuole PRXs. These positively selected sites showed significant effects on the biochemical functions of the enzymes. We also found that positive selection acts more frequently on residues adjacent to, rather than directly at, a critical active site of the enzyme, and on flexible regions rather than on rigid structural elements of the protein. Our study provides new insights into the adaptive molecular evolution of plant enzyme families.

B cells expressing CD11b effectively inhibit CD4+ T-cell responses and ameliorate experimental autoimmune hepatitis in mice.

UNLABELLED: Increasing evidence in recent years has suggested that B cells act as a crucial regulator in autoimmune diseases. However, little is known about their role in autoimmune hepatitis (AIH) and the underlying regulatory mechanisms. In this study, we show that B cells ameliorated experimental AIH (EAH) by suppressing CD4+ T-cell responses and that CD11b expression on B cells was required for the regulatory function of B cells. In vitro studies reveal that the suppressive function of CD11b was mediated by the impairment of T-cell antigen receptor (TCR) signaling transduction and the promotion of TCR down-regulation. Moreover, we show that the increased CD11b expression on B cells was interleukin (IL)-10 dependent and that additional IL-10 stimulation promoted CD11b expression on B cells, thereby enhancing B-cell regulatory effects. CONCLUSION: These findings reveal a previously unrecognized role for CD11b in B-cell regulatory function and its protective effect on EAH.

Thermochemical behavior of tris(2-butoxyethyl) phosphate (TBEP) during co-pyrolysis with biomass.

Co-pyrolysis of plastic waste and wood biomass to recover valuable chemicals is a cost-effective waste-recycling technology. However, widely used organophosphate ester additives in plastic, such as tris(2-butoxyethyl) phosphate (TBEP), can form diverse phosphorus (P)-containing species. These P-containing compounds can pose new environmental challenges when the biochar is reused. In this study, a mixture of TBEP and lignin was used to simulate the feedstock of plastic waste and wood biomass, and the thermochemical behavior of TBEP in slow pyrolysis (20 K min(-1)) and fast pyrolysis at 400-600 °C was investigated. The results show that low temperature in fast pyrolysis favors the enrichment of P in char. Up to 76.6% of initial P in the feedstock is retained in the char resulting from 400 °C, while only 51% is retained in the char from 600 °C. Slow pyrolysis favors the formation of stable P species regardless of the temperature; only 7% of the P retained in the char is extractable from char from slow pyrolysis, while 20-40% of P can be extracted from char resulting from fast pyrolysis. The addition of CaCl2 and MgCl2 can significantly increase the fraction of P retained in the char by the formation of Ca, Mg-P compounds. Online TG-FTIR-MS analysis suggests that TBEP undergoes decomposition through different temperature-dependent pathways. The P-containing radicals react with the aromatic rings produced by the pyrolysis of lignin to form Ar-P species, which is an important factor influencing the distribution and stabilization of P in char.

Investigation on the evolution of N-containing organic compounds during pyrolysis of sewage sludge.

Pyrolysis is an emerging technology for the disposal of huge amounts of sewage sludge. However, the thermochemical decomposition mechanism of organic compounds in sludge is still unclear. We adopt a novel online TG-FTIR-MS technology to investigate the pyrolysis of sludge. The sludge samples were pyrolyzed from 150 to 800 °C with heating rates of 10, 50, and 200 K min(-1). We found for the first time that the heating rate of pyrolysis can significantly change the species of liquid organic compounds produced, but cannot change the gaseous species produced under the same conditions. The contents of produced gas and liquid compounds, most of which were produced at 293-383 °C, are influenced by both the heating rate and temperature of pyrolysis. The results also showed that heterocyclic-N, amine-N, and nitrile-N compounds are obtained from the decomposition of N-compounds in sludge, such as pyrrolic-N, protein-N, amine-N, and pyridinic-N. Heterocyclic-N compounds are the dominant N-containing products, which can be due to the thermochemical decomposition of pyridine-N and pyrrole-N, whereas fewer amine-N compounds are produced during the pyrolysis. A mechanism for the decomposition of N-containing compounds in sludge is proposed based on the obtained data.

Preparation and characterization of nanosilica from oil shale ash.

Nano-sized silica powders was prepared using oil shale ash (OSA) as starting materials. A combined process was proposed for the utilization of OSA in the production of the nanosilica, including three stages: calcination, alkaline leaching and carbon dioxide separation. Effects of the calcining temperature, sodium hydroxide concentration and holding time on the desilication ratio were investigated. The microstructure and morphologies of the nano-sized silica were characterized by X-ray diffraction, transmission electron microscopy, and Brunauer-Emmett-Teller nitrogen-gas adsorption method. The results indicated that the obtained powders with particle size of about 40 nm are homegeneously dispersed and its specific surface area is 387 m2/g. The properties of the nano-sized silica powder meet the requirements of the Chinese Chemical Industry Standard HG/T 3061-1999.

Corneal epithelial thickness map in long-term soft contact lenses wearers.

PURPOSE: To map the corneal epithelial thickness in vivo with Fourier-domain optical coherence tomography in long-term soft contact lens (SCL) wearers. METHODS: This is a cross-sectional observational study. Forty eyes from 40 normal subjects who had never worn SCL and 40 eyes from 40 SCL wearers who had worn lenses for more than 2 years were enrolled. Corneal epithelium over the entire cornea was topographically imaged using a novel optical coherence tomography system. An epithelial thickness map was automatically generated. Epithelial thicknesses of the central 2-mm, paracentral 2- to 5-mm (P1), and midperipheral 5- to 6-mm (P2) zones were obtained. In addition, the epithelial map variability in P1 and P2 zones, including maximum - minimum (MAX - MIN), map SD, and coefficient of variation (CV), was measured and analyzed. RESULTS: The average epithelial thickness of the central, P1, and P2 zones was 54.4 ± 1.1 µm, 53.2 ± 2.2 µm, and 52.3 ± 2.0 µm, respectively, in normal eyes and 49.2 ± 1.9 µm, 48.8 ± 2.2 µm, and 48.7 ± 2.8 µm, respectively, in eyes wearing SCL. Compared with normal control subjects, eyes with long-term SCL had significantly thinner epithelial thickness in all three zones (p < 0.05). However, there was no difference in MAX - MIN, SD, and CV of P1 and P2 zones between two groups. In both groups, there was significant difference in the epithelial thickness among different sectors in the paracentral and midperipheral zones. CONCLUSIONS: There is a decrease in epithelial thickness in subjects who wear SCL long term. Clinicians should take note of the nonuniformity of the paracentral and midperipheral corneal epithelium thicknesses. This method may be useful for detecting early changes in corneal epithelial thickness caused by long-term SCL wear.