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OBJECTIVE: Lung adenocarcinoma (LA) is one of the most common malignancies and is responsible for the greatest number of tumor-related deaths. Our research aimed to explore the molecular subtype signatures of LA to clarify the correlation among the immune microenvironment, clinical outcomes, and therapeutic response. METHODS: The LA immune cell marker genes (LICMGs) identified by single-cell RNA sequencing (scRNA-seq) analysis were used to discriminate the molecular subtypes and homologous immune and metabolic traits of GSE72094 LA cases. In addition, the model-building genes were identified from 1441 LICMGs by Cox-regression analysis, and a LA immune difference score (LIDscore) was developed to quantify individual differences in each patient, thereby predicting prognosis and susceptibility to immunotherapy and chemotherapy of LA patients. RESULTS: Patients of the GSE72094 cohort were divided into two distinct molecular subtypes based on LICMGs: immune activating subtype (Cluster-C1) and metabolically activating subtype (cluster-C2). The two molecular subtypes have distinct characteristics regarding prognosis, clinicopathology, genomics, immune microenvironment, and response to immunotherapy. Among the LICMGs, LGR4, GOLM1, CYP24A1, SFTPB, COL1A1, HLA-DQA1, MS4A7, PPARG, and IL7R were enrolled to construct a LIDscore model. Low-LIDscore patients had a higher survival rate due to abundant immune cell infiltration, activated immunity, and lower genetic variation, but probably the higher levels of Treg cells in the immune microenvironment lead to immune cell dysfunction and promote tumor immune escape, thus decreasing the responsiveness to immunotherapy compared with that of the high-LIDscore patients. Overall, high-LIDscore patients had a higher responsiveness to immunotherapy and a higher sensitivity to chemotherapy than the low-LIDscore group. CONCLUSIONS: Molecular subtypes based on LICMGs provided a promising strategy for predicting patient prognosis, biological characteristics, and immune microenvironment features. In addition, they helped identify the patients most likely to benefit from immunotherapy and chemotherapy.
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Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Humanos , Pronóstico , Genes Reguladores , Adenocarcinoma del Pulmón/tratamiento farmacológico , Adenocarcinoma del Pulmón/genética , Fenotipo , Inmunoterapia , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Microambiente Tumoral/genética , Proteínas de la MembranaRESUMEN
Diabetic retinopathy (DR) is a severe and recurrent microvascular complication in diabetes. The multifunctional response gene to complement 32 (RGC-32) is involved in the regulation of cell cycle, proliferation, and apoptosis. To investigate the role of RGC-32 in the development of DR, we used human retinal microvascular endothelial cells under high-glucose conditions and type 2 diabetes (T2D) mice (+Leprdb/ + Leprdb, db/db). The results showed that RGC-32 expression increased moderately in human retinal endothelial cells under hyperglycemic conditions. Histopathology and RGC-32 expression showed no significant changes between T2D and control mice retina at 16 and 24 weeks of age. However, RGC-32 expression was significantly decreased in T2D mouse retina compared to the control group at 32 weeks of age, which develop features of the early clinical stages of DR, namely reduced retinal thickness and increased ganglion cell death. Moreover, immunohistochemistry showed that RGC-32 was predominantly expressed in the photoreceptor inner segments of control mice, while the expression was dramatically lowered in the T2D retinas. Furthermore, we found that the level of anti-apoptotic protein Bcl-2 was decreased (approximately 2-fold) with a concomitant increase in cleaved caspase-3 (approximately 3-fold) in T2D retina compared to control. In summary, RGC-32 may lose its expression in T2D retina with features of DR, suggesting that it plays a critical role in DR pathogenesis.
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Diabetes Mellitus Experimental/metabolismo , Retinopatía Diabética/metabolismo , Proteínas Nucleares/metabolismo , Retina/metabolismo , Animales , Apoptosis , Humanos , Hiperglucemia/metabolismo , Hiperglucemia/patología , Procesamiento de Imagen Asistido por Computador , Masculino , Ratones , Factores de TiempoRESUMEN
OBJECTIVE: To measure the content of silica in C1 bituminous coal and its combustion products in the high-incidence area of lung cancer in Xuanwei, Yunnan Province, China and to investigate the relationship between high incidence of lung cancer among non-smoking women and silica produced naturally in C1 bituminous coal in Xuan Wei. METHODS: The C1 bituminous coal widely used in the high-incidence area of lung cancer in Xuanwei was selected as experiment group, while the C2+1, K7, and M30 bituminous coal that was mined and used in the low-incidence area of lung cancer in Xuanwei for more than 10 years were selected as control group. Fourteen paraffin-embedded cancer tissue samples from the non-smoking women with non-small cell lung cancer who were born in Xuanwei and were at least the 3rd generation of the family living there were collected from the department of pathology, the third affiliated hospital of kunming medical university (tumor hospital of yunnan province). Titrimetric potassium silicofluoride method was used to measure the content of silica in raw coal and its bottom ashes in 20 samples from the experimental group and control group. Scanning electron microscopy (SEM) was used to observe the morphology of silica particles in C1 bituminous coal and its bottom ashes, and scanning electron microscopy coupled with energy dispersive X-ray analyzer (SEM-EDX) was used to analyze the microscopic composition. Transmission electron microscope (TEM) was used to observe the morphology of silica particles in the bottom ashes and coal soot of C1 bituminous coal as well as the lung cancer tissue from the non-smoking women in Xuanwei, and transmission electron microscope coupled with energy dispersive X-ray analyzer (TEM-EDX) was used to analyze the microscopic composition. The silica particles were separated from the coal soot and bottom ashes and characterized by physical method. RESULTS: The silica content in C1 bituminous coal and its bottom ashes was significantly higher than that in C2+1, K7, and M30 bituminous coal (P < 0.05). The bottom ashes of C1 bituminous coal contained a large quantity of silica particles, mostly with microscale sizes. Silica particles were found in the soot of C1 bituminous coal and the lung cancer tissue from non-smoking women in Xuanwei. The silica particles in the bottom ashes were mostly 120 â¼ 500 nm in diameter, had various shapes, and contained such elements as iron, aluminium, calcium, and potassium; the silica particles in the coal soot were mostly nanoscale, ranging from 37 nm to 80 nm in diameter, had various shapes, with some in fibrous form, had non smooth surfaces, and contained such elements as iron, potassium, calcium, aluminium, and sulfur. CONCLUSION: In Xuanwei, the incidence of lung cancer among non-smoking women is high in the area where silica-rich C1 bituminous coal is produced. There are silica particles enriched in both the combustion products (coal soot and bottom ashes) of C1 bituminous coal and the cancer tissue from the non-smoking women with non-small cell lung cancer, with similar morphology and microscopic composition. We hypothesize that the silica particles from combusted C1 bituminous coal in Xuanwei are mixed with indoor air and inhaled along with other suspended particles.
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Contaminantes Atmosféricos/análisis , Ceniza del Carbón/análisis , Neoplasias Pulmonares/epidemiología , Dióxido de Silicio/análisis , China/epidemiología , Carbón Mineral , Exposición a Riesgos Ambientales , Femenino , Humanos , Incidencia , Factores de Riesgo , FumarRESUMEN
BACKGROUND/AIM: Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and a major cause of blindness in working-age adults. Diosgenin (DG), a natural steroidal sapogenin extracted from fenugreek seeds and wild yam roots, has hypolipidemic, hypoglycemic, anticancer, and anti-inflammatory properties. Given its pharmacological effects, we speculated that DG may be a promising treatment for DR. Therefore, this study was aimed at evaluating the effectiveness of DG in preventing or slowing DR progression in a mouse model (+Leprdb/+Leprdb strain) of type 2 diabetes (T2D). MATERIALS AND METHODS: DG (5.0 mg/kg body weight) or phosphate-buffered saline (PBS) was administered to 8-week-old T2D mice via oral gavage daily for 24 weeks. Paraffin-embedded eye tissues from the mice were collected and stained with hematoxylin and eosin to evaluate retinal histopathology. Apoptosis-related proteins BCL2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), and cleaved caspase-3 were evaluated by western blotting of mouse retinas. RESULTS: Body weight was slightly reduced in the DG-treated group; however, glucose levels were not markedly different between the DG- and PBS-treated groups. Total retinal thickness, thickness of the photoreceptor and outer nuclear layers, and loss of ganglion cells significantly improved in the retina of the DG-treated T2D mice compared with those in the PBS-treated T2D mice. Cleaved caspase-3 level significantly decreased in the retina of the DG-treated T2D mice. Conclusion: DG alleviates DR pathology and exerts a protective effect on the T2D mouse retina. The inhibitory effects of DG on DR may involve mechanisms of the anti-apoptotic pathway.
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Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Retinopatía Diabética , Diosgenina , Sapogeninas , Animales , Ratones , Retinopatía Diabética/etiología , Retinopatía Diabética/genética , Caspasa 3 , Sapogeninas/farmacología , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/tratamiento farmacológico , Peso Corporal , Diosgenina/farmacologíaRESUMEN
Daphnoretin extracted from the stem and roots of Wikstroemia indica (L.) C.A. Mey has been shown to possess antiviral and antitumor activities. Herein, we hypothesized that daphnoretin might induce megakaryocytic differentiation, thereby inhibiting the proliferation of cells and serving as a differentiation therapy agent for chronic myeloid leukemia (CML). Daphnoretin-treated K562 and HEL cells were examined for growth inhibition, cell morphology, and megakaryocyte-specific markers. Potential mechanisms of megakaryocytic differentiation of daphnoretin-treated K562 cells were evaluated. The results showed that daphnoretin inhibited the growth of K562 and HEL cells in a dose- and time-dependent manner. Flow cytometry analyses revealed that daphnoretin treatment slightly increased the proportion of sub-G1 and polyploid cells compared to that of dimethyl sulfoxide (DMSO)-treated control cells. Morphological examination showed that daphnoretin-treated K562 and HEL cells exhibited enlarged contours and multinucleation as megakaryocytic characteristics compared to DMSO-treated control cells. Daphnoretin treatment also dramatically enhanced the expression of megakaryocytic markers CD61 and CD41. Under optimal megakaryocytic differentiation conditions, daphnoretin increased the phosphorylation of STAT3 but not STAT5. In summary, daphnoretin inhibited cell growth and induced megakaryocytic differentiation in K562 and HEL cells. The efficacy of daphnoretin in vivo and in patients with CML may need further investigations for validation.
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Leucemia Mielógena Crónica BCR-ABL Positiva , Leucemia Mieloide , Humanos , Dimetilsulfóxido/farmacología , Diferenciación Celular , Leucemia Mieloide/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Antivirales/farmacologíaRESUMEN
BACKGROUND: The cellular immunity of lung cancer patients is mainly the immune response of T cells, which plays an important role in tumour cell killing and immune surveillance. Transforming growth factor 1 (TGF-ß1) is secreted by tumour cells that can suppress the immune response and is an important group of immune down-regulation factors. Our study aims to investigate the effect of TGF-ß1 on the morphology and cellular immune function of A549 and peripheral blood mononuclear cells (PBMCs). METHODS: A549 cell line was cultured, PBMCs were cultured with different concentrations of TGF-ß1, and the morphology of A549 cells and PBMCs were seen. The levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IFN-γ, and TNF and the numbers of CD3, CD4, CD8, CD4/CD8, and CD3 CD25 and CD4 CD25 in PBMCs were detected. RESULTS: During co-culture of A549 with PBMCs, TGF-ß1 can induced A549 showing epithelial-to-mesenchymal transition, enhanced its ability of migration and infiltration. Simultaneously, TGF-ß1 can depressing the growth and proliferation of PBMCs, inhibiting T-cell activation, and accelerating the PBMCs apoptosis. TGF-ß1 can inhibits A549 Th1 related-cytokines, enhance Th2 related-cytokines, cause the disorder of Th1/Th2, resulting in the Th1 cellular dominate immunity decline. CONCLUSIONS: TGF-ß1 may affect the secretion of related cytokines, hinder the activation of T lymphocytes, destroy the immune surveillance and killing effect of the body, and thus inhibit the cellular immunity.
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BACKGROUND/AIM: Diabetic retinopathy (DR) is a type of retinal damage caused by a complication of diabetes and is a major cause of blindness in working-age adults. Ecto-NOX disulfide-thiol exchanger 1 (ENOX1) is a member of the ecto-NOX family involved in the plasma membrane electron transport pathway. This study aimed to investigate the role of ENOX1 in the development of DR. MATERIALS AND METHODS: Human retinal endothelial cells (HRECs) and human retinal pigment epithelial cells (HREpiCs) exposed to a high concentration (25 mM) of D-glucose and type 2 diabetes (T2D) mice (+Leprdb/+Leprdb, db/db) with retinopathy were used as models to determine the ENOX1 expression levels there. RESULTS: Our results showed that ENOX1 expression levels did not significantly change in both HRECs and HREpiCs under hyperglycemic conditions for 48 h. Nevertheless, ENOX1 expression increased significantly in T2D mouse retinas, particularly in the photoreceptor layer, compared to the control mouse retinas. CONCLUSION: Different retinal ENOX1 expression in T2D mice and control mice suggested that ENOX1 may be involved in DR development.
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Diabetes Mellitus Experimental/metabolismo , Retinopatía Diabética/metabolismo , NADH NADPH Oxidorreductasas/metabolismo , Retina/metabolismo , Animales , Células Cultivadas , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Retinopatía Diabética/patología , Células Endoteliales/metabolismo , Células Endoteliales/patología , Humanos , Masculino , Ratones , Retina/patologíaRESUMEN
Cholesteryl ester transfer protein (CETP) plays an important role in lipid metabolism. Low levels of high-density lipoprotein cholesterol (HDL-C) increase the risk of type 2 diabetes (T2D). This study investigated CETP gene variants to assess the risk of T2D and specific complications of diabetic kidney disease (DKD) and diabetic retinopathy. Towards this, a total of 3023 Taiwanese individuals (1383 without T2D, 1640 with T2D) were enrolled in this study. T2D mice (+Leprdb/+Leprdb, db/db) were used to determine CETP expression in tissues. The A-alleles of rs3764261, rs4783961, and rs1800775 variants were found to be independently associated with 2.86, 1.71, and 0.91 mg/dL increase in HDL-C per allele, respectively. In addition, the A-allele of rs4783961 was significantly associated with a reduced T2D risk (odds ratio (OR), 0.82; 95% confidence interval (CI), 0.71â0.96)), and the A-allele of rs1800775 was significantly related to a lowered DKD risk (OR, 0.78; 95% CI, 0.64â0.96). CETP expression was significantly decreased in the T2D mice kidney compared to that in the control mice (T2D mice, 0.16 0.01 vs. control mice, 0.21 0.02; p = 0.02). These collective findings indicate that CETP variants in the promoter region may affect HDL-C levels. Taiwanese individuals possessing an allele associated with higher HDL-C levels had a lower risk of T2D and DKD.
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Proteínas de Transferencia de Ésteres de Colesterol/genética , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Animales , Pueblo Asiatico/genética , Proteínas de Transferencia de Ésteres de Colesterol/metabolismo , HDL-Colesterol/genética , Diabetes Mellitus Tipo 2/genética , Nefropatías Diabéticas/genética , Retinopatía Diabética/genética , Femenino , Frecuencia de los Genes/genética , Predisposición Genética a la Enfermedad/genética , Variación Genética/genética , Genotipo , Humanos , Masculino , Ratones , Persona de Mediana Edad , Polimorfismo Genético/genética , Factores de Riesgo , Taiwán/epidemiologíaRESUMEN
Diabetic retinopathy (DR) is a common microvascular complication of diabetes. Circulating endothelial progenitor cells (EPCs) are derived from bone marrow and are characterized by pathological retinal neovascularization. Rho GTPase Activating Protein 22 (ARHGAP22) is a DR susceptibility gene that interacts with its downstream regulatory protein ras-related C3 botulinum toxin substrate 1 (Rac1), to assist in endothelial cell angiogenesis and increasing capillary permeability. The aim of this study was to elucidate the relationship between ARHGAP22 expression and EPC levels in type 2 diabetes (T2D) patients with DR. Fifty T2D patients with DR were recruited. Circulating EPCs were characterized as CD31+/vascular endothelial growth factor-2+/CD45dim/CD133+ and were quantified using triple staining flow cytometry. Real-time polymerase chain reaction tests were used to quantify ARHGAP22 expression. We found that T2D patients with proliferative DR had significantly lower EPC levels than those with non-proliferative DR (P = 0.028). T2D patients with EPC levels above the median value (> 4 cells/105 events) had higher levels of ARHGAP22 expression (P = 0.002). EPC levels were positively correlated with ARHGAP22 expression (r = 0.364, P = 0.009). Among T2D patients with DR, a higher expression of ARHGAP22 was associated with higher levels of EPCs. ARHGAP22 may be involved in the mobilization or active circulation of EPCs, thus contributing to neovascularization during DR development.
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OBJECTIVE: To investigate the relationship between miR-501-5p expression and the clinicopathological factors in patients with lung adenocarcinoma in Xuanwei area. METHODS: Surgical specimens of lung adenocarcinoma and paired adjacent tissues from 24 patients with lung adenocarcinoma from Xuanwei area were examined for miR-501-5p expression using microRNA microarray technique and qPCR. Chi-square test was used to analyze the association of miR-501-5P expression with the clinicopathological characteristics of the patients. Multiple regression analysis was performed to analyze the association of miR-501-5p expression with the patients' gender, age, tumor stage, and preoperative CEA level. RESULTS: MicroRNA microarray analysis and qPCR validation results revealed significantly upregulated expressions of miR-501-5p in patients with lung adenocarcinoma from Xuanwei area (Plt;0.01). The microarray data showed an up-regulation of miR-501-5p by 3.17 folds in lung adenocarcinoma tissue compared with the adjacent tissue (P=0.22376, FDR=0.071395). Chi-square test indicated that miR-501-5p expression level was associated with the patients' age (f=7.168, P=0.014), TNM stage (f=36.627, P<0.01), and preoperative serum CEA level (f=30.045, Plt;0.01), but not with the patients' gender (f=3.612, P=0.071). Multiple regression analysis revealed that miR-501-5p expression was positively correlated with the patients' age, TNM stage of the tumor, and serum CEA (Plt;0.05). CONCLUSION: miR-501-5p expression is up-regulated in lung adenocarcinoma with significant associations with the patients' age, TNM stages and serum CEA level in patients from Xuanwei area, suggesting its potential role in the tumorigenesis and progression of lung adenocarcinoma in Xuanwei area.
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Adenocarcinoma/genética , Neoplasias Pulmonares/genética , MicroARNs/genética , Adenocarcinoma del Pulmón , China , Regulación Neoplásica de la Expresión Génica , Humanos , Estadificación de NeoplasiasRESUMEN
The aim of this study was to investigate the function of miR-1244 in cisplatin-treated non-small cell lung cancer (NSCLC). The results of quantitative PCR analysis revealed that the expression levels of miR-1244 in cisplatintreated A549 and NCI-H522 human lung cancer cell lines were lower than those in untreated A549 and NCI-H522 cells. Similarly, the expression level of miR-1244 in NSCLC tissue samples from cisplatin-treated patients was also lower than that in non-cisplatin-treated NSCLC patients. Notably, the overall survival times of cisplatin-treated NSCLC patients with high miR-1244 expression were superior to those patients with low miR-1244 expression. We found that overexpression of miR-1244 suppressed cell viability and increased LDH toxicity in cisplatin-treated A549 and NCI-H522 cells. Additionally, overexpression of miR-1244 induced the apoptosis of cisplatin-treated A549 and NCI-H522 cells. Furthermore, overexpression of miR-1244 promoted caspase-3 activity and p53 and Bax protein expression, and suppressed myocyte enhancer factor 2D (MEF2D) and cyclin D1 protein expression in cisplatintreated A549 and NCI-H522 cells. Small interfering RNA (siRNA) targeting MEF2D suppressed the protein expression of MEF2D, and was able to decrease the proliferation, promote caspase-3 activity, p53 and Bax protein expression and inhibit cyclin D1 protein expression in cisplatin-treated A549 and NCI-H522 cells following the overexpression of miR-1244. In summary, we found that miR-1244 affected cisplatin-treated NSCLC via MEF2D expression.
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Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Cisplatino/administración & dosificación , MicroARNs/genética , Células A549 , Apoptosis/efectos de los fármacos , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Caspasa 3/genética , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Cisplatino/efectos adversos , Ciclina D1/genética , Resistencia a Antineoplásicos/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Factores de Transcripción MEF2/genética , Proteína p53 Supresora de Tumor/genética , Proteína X Asociada a bcl-2/genéticaRESUMEN
OBJECTIVE: To identify differentially expressed microRNAs (miRNAs) related to lung adenocarcinoma in Xuanwei region and predict their target genes and related signaling pathways based on bioinformatic analysis. METHODS: High-throughput microarray assay was performed to detect miRNA expression profiles in 34 paired human lung adenocarcinoma and adjacent normal tissues (including 24 cases in Xuanwei region and 10 in other regions). Gene ontology and KEGG pathway analyses were used to predict the target genes and the regulatory signaling pathways. RESULTS: Thirty-four miRNAs were differentially expressed in lung adenocarcinoma tissues in cases in Xuanwei region as compared with cases in other regions, including 23 upregulated and 11 downregulated miRNAs. The predicted target genes included GF, RTK, SOS, IRS1, BCAP, CYTOKINSR, ECM, ITGB, FAK and Gbeta;Y involving the PI3K/Alt, WNT and MAPK pathways. CONCLUSION: The specific microRNA expression profiles of lung adenocarcinoma in cases found in Xuanwei region allow for a better understanding of the pathogenesis of lung adenocarcinoma in Xuanwei. The predicted target genes may involve the PI3K/Alt, WNT and MAPK pathways.
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Adenocarcinoma/metabolismo , Biología Computacional , Neoplasias Pulmonares/metabolismo , MicroARNs/metabolismo , Transducción de Señal , Adenocarcinoma/genética , Adenocarcinoma del Pulmón , Perfilación de la Expresión Génica , Humanos , Pulmón/metabolismo , Neoplasias Pulmonares/genética , MicroARNs/genéticaRESUMEN
The objective of the study was to establish an in vitro model of Candida albicans-Staphylococcus epidermidis mixed species biofilm (BF) on polyvinyl chloride (PVC) material, and to investigate the formation and the structure of mixed species BF formation using a combined approach of confocal laser scanning microscope (CLSM), scanning electron microscope (SEM), and 3D image reconstruction technique. Mixed species BF is achieved by co-incubating Staphylococcus epidermidis bacteria (ATCC35984) and Candida albicans fungal (ATCC10231) with PVC pieces in Tris-buffered saline. BF formation was examined at 2, 6, 12, 24, 48, and 72 h of co-culture. Thickness of these BFs and the number, and percentage of viable cells in BFs were measured. CT scan images of BFs were obtained using CLSM and SEM and reconstructed 3D images of mixed species BF were acquired, in an effort to examine structure of the BF. Staphylococcus epidermidis attached to various forms of candida albicans (spores, pseudohyphae, and hyphae), formed complex and dense mesh arrays. The BF is constituted of a large number of viable and dead pathogens, the surface of mixed species BF is uneven, with living pathogens predominating protrusive portions and dead pathogens aggregating in concaves. Mixed species BF formation on the surface of PVC material was found to be a dynamic process, with rapid growth being at 24 h of co-culture, maximal thickness peaked at 48 h. These mixed species BF matured at 48-72 h. Significant differences were observed in the proportion of viable cells between interior, middle, and outer layers of BFs (p < 0.05). Mixed species BF Candida albicans-Staphylococcus epidermidis is sophisticated in structure. The combined approach involving CLSM, SEM, and 3D image reconstruction technique is ideal for the investigation of mixed species BF on PVC material.
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Materiales Biocompatibles/farmacología , Biopelículas/efectos de los fármacos , Candida albicans/fisiología , Cloruro de Polivinilo/farmacología , Staphylococcus epidermidis/fisiología , Materiales Biocompatibles/química , Biopelículas/crecimiento & desarrollo , Microscopía Confocal , Microscopía Electrónica de Rastreo , Modelos Biológicos , Cloruro de Polivinilo/químicaRESUMEN
The aim of the study was to establish an in vitro model of Staphylococcus epidermidis biofilms on polyvinyl chloride (PVC) material, and to investigate bacterial biofilm formation and its structure using the combined approach of confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM). Staphylococcus epidermidis bacteria (stain RP62A) were incubated with PVC pieces in Tris buffered saline to form biofilms. Biofilm formation was examined at 6, 12, 18, 24, 30, and 48 h. Thicknesses of these biofilms and the number, and percentage of viable cells in biofilms were measured. CT scan images of biofilms were obtained using CLSM and environmental SEM. The results of this study showed that Staphylococcus epidermidis biofilm is a highly organized multi-cellular structure. The biofilm is constituted of large number of viable and dead bacterial cells. Bacterial biofilm formation on the surface of PVC material was found to be a dynamic process with maximal thickness being attained at 12-18 h. These biofilms became mature by 24 h. There was significant difference in the percentage of viable cells along with interior, middle, and outer layers of biofilms (P < 0.05). Staphylococcus epidermidis biofilm is sophisticated in structure and the combination method involving CLSM and SEM was ideal for investigation of biofilms on PVC material.