M R Chacón

Publications (14)46.84 Total impact

• Article: Distribution of virulence genes in clinical and environmental isolates of Aeromonas spp.

  M.R. Chacón, M.J. Figueras, G. Castro-Escarpulli, L. Soler, J. Guarro
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  ABSTRACT: The distribution and phenotypic activity of the genes encoding for serine protease, glycerophospholipid-cholesterol acyltransferase, lipases, aerolysin/hemolysin and DNases were investigated in 234 isolates identified by 16S rDNA-RFLP representing all the species of Aeromonas. The former three genes were found to be highly conserved among the genus. Aerolysin/hemolysin and DNase genes and β-hemolytic activity were significantly more frequent in clinical than in environmental isolates. Aerolysin/hemolysin and serine protease genes were present in all β-hemolytic strains supporting serine protease as possibly important for the activation of the former gene. The high prevalence of virulence factors in clinical isolates indicates that they may play a role in the mechanisms of pathogenesis of these microorganisms.
  Antonie van Leeuwenhoek 04/2012; 84(4):269-278. · 2.09 Impact Factor
• Article: Plasma PTX3 protein levels inversely correlate with insulin secretion and obesity, whereas visceral adipose tissue PTX3 gene expression is increased in obesity.

  O Osorio-Conles, M Guitart, M R Chacón, E Maymo-Masip, J M Moreno-Navarrete, M Montori-Grau, S Näf, J M Fernandez-Real, J Vendrell, A M Gómez-Foix
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  ABSTRACT: Plasma acutephase protein pentraxin 3 (PTX3) concentration is dysregulated in human obesity and metabolic syndrome. Here, we explore its relationship with insulin secretion and sensitivity, obesity markers, and adipose tissue PTX3 gene expression. Plasma PTX3 protein levels were analyzed in a cohort composed of 27 lean [body mass index (BMI) ≤ 25 kg/m(2)] and 48 overweight (BMI 25-30 kg/m(2)) men (cohort 1). In this cohort, plasma PTX3 was negatively correlated with fasting triglyceride levels and insulin secretion after intravenous and oral glucose administration. Plasma PTX3 protein and PTX3 gene expression in visceral (VAT) and subcutaneous (SAT) whole adipose tissue and adipocyte and stromovascular fractions were analyzed in cohort 2, which was composed of 19 lean, 28 overweight, and 15 obese subjects (BMI >30 kg/m(2)). An inverse association with body weight and waist/hip ratio was observed in cohort 2. In VAT depots, PTX3 mRNA levels were higher in subjects with BMI >25 kg/m(2) than in lean subjects, positively correlated with IL-1β mRNA levels, and higher in the adipocyte than stromovascular fraction. Human preadipocyte SGBS cell line was used to study PTX3 production in response to factors that obesity entails. In SGBS adipocytes, PTX3 gene expression was enhanced by IL-1β and TNFα but not IL-6 or insulin. In conclusion, the negative correlation between PTX3 and glucose-stimulated insulin secretion suggests a role for PTX3 in metabolic control. PTX3 gene expression is upregulated in VAT depots in obesity, despite lower plasma PTX3 protein, and by some proinflammatory cytokines in cultured adipocytes.
  AJP Endocrinology and Metabolism 09/2011; 301(6):E1254-61. · 4.75 Impact Factor
• Article: Human serum levels of fetal antigen 1 (FA1/Dlk1) increase with obesity, are negatively associated with insulin sensitivity and modulate inflammation in vitro.

  M R Chacón, M Miranda, C H Jensen, J M Fernández-Real, N Vilarrasa, C Gutiérrez, S Näf, J M Gomez, J Vendrell
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  ABSTRACT: To investigate fetal antigen 1 (FA1) protein within the context of human obesity and its relation with insulin sensitivity. Cross-sectional study that analyses circulating levels of FA1 in two selected human cohorts: n=127 men for the study of FA1 circulating levels in the context of obesity and insulin sensitivity (S(i)); and n=61 severely obese women before and after bariatric surgery. The response in vitro to FA1 protein on human cell lines of monocytes, preadipocytes and mature adipocytes was studied. Anthropometrical parameters: body mass index, waist-to-hip ratio, waist circumference, fat-free mass and fat mass. Clinical parameters: lipid profile (high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides), glycemic profile (fasting glucose, insulin, S(i), HOMA-IR (Homeostasis Model Assessment of Insulin Resistance), cytokines (sIL-6), adipokines (adiponectin) and circulating soluble fractions of tumor necrosis factor-alpha receptors 1 and 2 (sTNFR1 and sTNFR2). IN the obesity study, levels of FA1 in serum were found to increase with obesity. The S(i) index was negatively dependent on FA1 levels. In severe obesity, serum levels of FA1 decreased 1.4-fold 6 months after bariatric surgery. In vitro assays with FA1 protein on human monocytes and adipocytes cell lines modified the expression of pro-inflammatory cytokines and adipokines (tumor necrosis factor-alpha (TNFalpha), monocyte chemoattractant protein-1 (MCP-1), IL-6 (interleukin-6) and adiponectin). FA1 serum levels were increased in obese subjects and might influence S(i). The stimulatory effect of FA1 protein on pro-inflammatory cytokines on both immune and adipose cell types could contribute to worsening the inflammatory environment observed in obesity.
  International journal of obesity (2005) 08/2008; 32(7):1122-9. · 4.34 Impact Factor
• Article: Different TNFalpha expression elicited by glucose in monocytes from type 2 diabetes mellitus patients.

  M R Chacón, J Vendrell, M Miranda, V Ceperuelo-Mallafré, A Megía, C Gutiérrrez, J M Fernández-Real, C Richart, A Garcia-España
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  ABSTRACT: Increased plasma concentrations of tumor necrosis factor alpha (TNFalpha) system components appear in type 2 diabetes patients with poor glycemic control. We have analyzed the expression of TNFalpha, TNFR1 and TNFR2 when monocytes and lymphocytes isolated from a group of recent onset type 2 diabetic patients, with fasting glucose levels below 7.0mM and glycated haemoglobin (Hb1Ac) in the normal range, were stimulated with high glucose or LPS endotoxin. We report, that cultured monocytes from these type 2 diabetic patients, in comparison to monocytes from non-diabetic individuals, had an enhanced response to LPS but did not respond to an acute glucose challenge (p<0.05). No differences were observed in the cultured lymphocyte fractions. These results indicate the existence of differences, elicited by LPS or high glucose related stimulus, between monocytes isolated from non-diabetic subjects or from type 2 diabetes patients.
  Atherosclerosis 11/2007; 194(2):e18-25. · 3.79 Impact Factor
• Article: Adipose tissue expression of the glycerol channel aquaporin-7 gene is altered in severe obesity but not in type 2 diabetes.

  V Ceperuelo-Mallafré, M Miranda, M R Chacón, N Vilarrasa, A Megia, C Gutiérrez, J M Fernández-Real, J M Gómez, E Caubet, G Frühbeck, J Vendrell
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  ABSTRACT: Aquaporin-7 is required for efflux of glycerol from adipocytes and influences whole-body glucose homeostasis in animal studies. Our objective was to test the hypothesis that AQP7 gene expression levels may be affected by presence of obesity and type 2 diabetes in humans. The obesity study cohort consisted of 12 lean, 22 nonseverely obese, and 13 severely obese subjects. The type 2 diabetes study cohort consisted of 17 lean and 39 obese type 2 diabetic patients. Circulating levels of plasma soluble proteins monocyte chemoattractant protein-1, TNF receptors 1 and 2, and IL-6 and glycerol were measured. The sc adipose tissue gene expression of AQP7, MCP-1, IL-6, TNFalpha, PPARgamma, and SREBP1c genes was measured by real-time PCR. AQP7 gene mutation analysis was performed. Severely obese women showed lower AQP7 expression levels compared with lean and nonseverely obese (P < 0.001). Moreover, circulating glycerol concentration was lower in severely obese subjects, but no correlation with AQP7 adipose tissue expression was observed. AQP7 expression was negatively related with proinflammatory genes (for monocyte chemoattractant protein-1, r = -0.203 and P = 0.044; for TNFalpha, r = -0.209 and P = 0.036). Concerning adipogenic factors, AQP7 expression levels were found to be positively determined by PPARgamma mRNA expression levels (r = 0.265; P = 0.012). AQP7 expression did not show differences regarding the presence of type 2 diabetes. Expression of AQP7 is down-regulated in women with severe obesity. The expression of this glycerol channel is not affected by type 2 diabetes.
  Journal of Clinical Endocrinology &amp Metabolism 09/2007; 92(9):3640-5. · 6.50 Impact Factor
• Article: Expression of TWEAK and its receptor Fn14 in human subcutaneous adipose tissue. Relationship with other inflammatory cytokines in obesity.

  M R Chacón, C Richart, J M Gómez, A Megía, N Vilarrasa, J M Fernández-Real, A García-España, M Miranda, C Masdevall, W Ricard, E Caubet, J Soler, J Vendrell
  [show abstract] [hide abstract]
  ABSTRACT: TWEAK, a cytokine of the TNF family, has been found to be expressed under different inflammatory conditions but no data is available concerning the expression of this cytokine and its receptor (Fn14) in human obesity. In the present work we have evaluated the expression of many pro-inflammatory TNF system cytokines (TNF-alpha, TWEAK and their respective receptors, TNFR1, TNFR2 and Fn14) in human adipose tissue of 84 subjects some with different degree of obesity and type 2 diabetes, and its relation with inflammation by also measuring the expression of macrophage marker CD68. We detected expression of TWEAK and Fn14 in isolated mature adipocytes and in the stromovascular fraction. Additionally, we found that LPS upregulates the expression of both genes on THP-1 human monocytic cell line. TWEAK was expressed in adipose tissue of all studied subjects with no differences between obesity group, and was associated with Fn14 expression in morbid obese, mainly in women with type 2 diabetes. The data obtained here also showed that TNF-alpha and TNFR2 mRNAs were significantly more expressed in subcutaneous adipose tissue of subjects with morbid obesity compared to obese and non-obese subjects. In contrast, TNFR1 gene expression was negatively associated with BMI. Our results suggest that the expression of TNF-derived pro-inflammatory cytokines are increased in severe obesity, where macrophage infiltrate could modulate the inflammatory environment through activation of its receptors.
  Cytokine 03/2006; 33(3):129-37. · 3.02 Impact Factor
• Article: First record of the rare species Aeromonas culicicola from a drinking water supply.

  M J Figueras, A Suarez-Franquet, M R Chacón, L Soler, M Navarro, C Alejandre, B Grasa, A J Martínez-Murcia, J Guarro
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  ABSTRACT: We describe the recovery of the rare species Aeromonas culicicola, so far known only in mosquitoes in India, from a drinking water supply in Spain. Typing, using enterobacterial repetitive intergenic consensus-PCR, revealed that the 27 new isolates belonged to 3 very closely related strains. These strains were genetically identified by 16S rRNA gene sequencing. Spanish strains differed from the mosquito strains in three nucleotide positions. The AHCYTOEN gene was present in these water strains, which may have a public health significance.
  Applied and Environmental Microbiology 02/2005; 71(1):538-41. · 3.83 Impact Factor
• Source

  Available from: ncbi.nlm.nih.gov

  Article: Type III secretion system genes in clinical Aeromonas isolates.

  M R Chacón, L Soler, E A Groisman, J Guarro, M J Figueras
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  ABSTRACT: We have identified the genes ascF and ascG, which encode components of a putative type III secretion system (TTSS) in AEROMONAS: We investigated the distribution of these and other TTSS genes in 84 clinical isolates and found hybridizing sequences in 50% of the strains, with a higher prevalence in Aeromonas hydrophila and Aeromonas veronii than in Aeromonas caviae.
  Journal of Clinical Microbiology 04/2004; 42(3):1285-7. · 4.15 Impact Factor
• Source

  Available from: ncbi.nlm.nih.gov

  Article: Evaluation of two miniaturized systems, MicroScan W/A and BBL Crystal E/NF, for identification of clinical isolates of Aeromonas spp.

  L Soler, F Marco, J Vila, M R Chacón, J Guarro, M J Figueras
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  ABSTRACT: Fifty-two clinical strains and 22 type and reference Aeromonas strains, previously genetically characterized by 16S rRNA gene restriction fragment length polymorphism, were identified in parallel with the MicroScan Walk/Away and BBL Crystal Enteric/Nonfermenter systems. The former identified only 14.8% of the isolates correctly, and the latter identified only 20.3% correctly, which indicates that neither of these systems is useful for this purpose.
  Journal of Clinical Microbiology 01/2004; 41(12):5732-4. · 4.15 Impact Factor
• Article: Characterisation of Aeromonas spp. isolated from frozen fish intended for human consumption in Mexico.

  G Castro-Escarpulli, M J Figueras, G Aguilera-Arreola, L Soler, E Fernández-Rendón, G O Aparicio, J Guarro, M R Chacón
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  ABSTRACT: A total of 82 strains of presumptive Aeromonas spp. were identified biochemically and genetically (16S rDNA-RFLP). The strains were isolated from 250 samples of frozen fish (Tilapia, Oreochromis niloticus niloticus) purchased in local markets in Mexico City. In the present study, we detected the presence of several genes encoding for putative virulence factors and phenotypic activities that may play an important role in bacterial infection. In addition, we studied the antimicrobial patterns of those strains. Molecular identification demonstrated that the prevalent species in frozen fish were Aeromonas salmonicida (67.5%) and Aeromonas bestiarum (20.9%), accounting for 88.3% of the isolates, while the other strains belonged to the species Aeromonas veronii (5.2%), Aeromonas encheleia (3.9%) and Aeromonas hydrophila (2.6%). Detection by polymerase chain reaction (PCR) of genes encoding putative virulence factors common in Aeromonas, such as aerolysin/hemolysin, lipases including the glycerophospholipid-cholesterol acyltransferase (GCAT), serine protease and DNases, revealed that they were all common in these strains. Our results showed that first generation quinolones and second and third generation cephalosporins were the drugs with the best antimicrobial effect against Aeromonas spp. In Mexico, there have been few studies on Aeromonas and its putative virulence factors. The present work therefore highlights an important incidence of Aeromonas spp., with virulence potential and antimicrobial resistance, isolated from frozen fish intended for human consumption in Mexico City.
  International Journal of Food Microbiology 08/2003; 84(1):41-9. · 3.33 Impact Factor
• Article: Distribution of virulence genes in clinical and environmental isolates of Aeromonas spp.

  M R Chacón, M J Figueras, G Castro-Escarpulli, L Soler, J Guarro
  [show abstract] [hide abstract]
  ABSTRACT: The distribution and phenotypic activity of the genes encoding for serine protease, glycerophospholipid-cholesterol acyltransferase, lipases, aerolysin/hemolysin and DNases were investigated in 234 isolates identified by 16S rDNA-RFLP representing all the species of Aeromonas. The former three genes were found to be highly conserved among the genus. Aerolysin/hemolysin and DNase genes and beta-hemolytic activity were significantly more frequent in clinical than in environmental isolates. Aerolysin/hemolysin and serine protease genes were present in all beta-hemolytic strains supporting serine protease as possibly important for the activation of the former gene. The high prevalence of virulence factors in clinical isolates indicates that they may play a role in the mechanisms of pathogenesis of these microorganisms.
  Antonie van Leeuwenhoek 02/2003; 84(4):269-78. · 2.09 Impact Factor
• Article: A DNA probe specific for Aeromonas colonies.

  M R Chacón, G Castro-Escarpulli, L Soler, J Guarro, M J Figueras
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  ABSTRACT: Members of the genus Aeromonas are important enteropathogens. Commercial identification systems are often unable to correctly identify Aeromonas strains and misidentification as Vibrio spp. is common. A digoxigenin-DNA probe based on a 237 bp of the glycerophospholipid-cholesterol acyltransferase gene has been tested in a colony hybridization assay. The probe hybridized with all Aeromonas species tested (n = 16) but not with strains of other enteropathogenic bacteria (n = 20). The probe allowed the unequivocal identification of Aeromonas in primary isolation media within 36 h.
  Diagnostic Microbiology and Infectious Disease 12/2002; 44(3):221-5. · 2.53 Impact Factor
• Source

  Available from: sgmjournals.org

  Article: Extended method for discrimination of Aeromonas spp. by 16S rDNA RFLP analysis.

  M J Figueras, L Soler, M R Chacón, J Guarro, A J Martínez-Murcia
  [show abstract] [hide abstract]
  ABSTRACT: A previously described molecular method, based on 16S rDNA RFLP analysis, for the identification of Aeromonas spp. was unable to separate the species Aeromonas salmonicida, Aeromonas bestiarum and the recently described Aeromonas popoffii. In this study, the method has been extended with endonucleases AIwNI and PstI for the identification of these species. A molecular frame for the identification of all known Aeromonas spp. is presented.
  International journal of systematic and evolutionary microbiology 12/2000; 50 Pt 6:2069-73. · 2.27 Impact Factor
• Article: Expression of TWEAK and its receptor Fn14 in human subcutaneous adipose tissue. Relationship with other inflammatory cytokines in obesity

  M.R. Chacón, C. Richart, J.M. Gómez, A. Megía, N. Vilarrasa, J.M. Fernández-Real, A. García-España, M. Miranda, C. Masdevall, W. Ricard, E. Caubet, J. Soler, J. Vendrell
  [show abstract] [hide abstract]
  ABSTRACT: TWEAK, a cytokine of the TNF family, has been found to be expressed under different inflammatory conditions but no data is available concerning the expression of this cytokine and its receptor (Fn14) in human obesity. In the present work we have evaluated the expression of many pro-inflammatory TNF system cytokines (TNF-α, TWEAK and their respective receptors, TNFR1, TNFR2 and Fn14) in human adipose tissue of 84 subjects some with different degree of obesity and type 2 diabetes, and its relation with inflammation by also measuring the expression of macrophage marker CD68. We detected expression of TWEAK and Fn14 in isolated mature adipocytes and in the stromovascular fraction. Additionally, we found that LPS upregulates the expression of both genes on THP-1 human monocytic cell line. TWEAK was expressed in adipose tissue of all studied subjects with no differences between obesity group, and was associated with Fn14 expression in morbid obese, mainly in women with type 2 diabetes.The data obtained here also showed that TNF-α and TNFR2 mRNAs were significantly more expressed in subcutaneous adipose tissue of subjects with morbid obesity compared to obese and non-obese subjects. In contrast, TNFR1 gene expression was negatively associated with BMI. Our results suggest that the expression of TNF-derived pro-inflammatory cytokines are increased in severe obesity, where macrophage infiltrate could modulate the inflammatory environment through activation of its receptors.
  Cytokine.