Luis Barreiro

Publications (2)35.29 Total impact

• Source

  Available from: Clémentine Chalmey

  Article: Lack of association between genetic polymorphisms in enzymes associated with folate metabolism and unexplained reduced sperm counts.

  Celia Ravel, Sandra Chantot-Bastaraud, Clementine Chalmey, Luis Barreiro, Isabelle Aknin-Seifer, Jerome Pfeffer, Isabelle Berthaut, E Emmanuelle Mathieu, Jacqueline Mandelbaum, Jean-Pierre Siffroi, Ken McElreavey, Anu Bashamboo
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  ABSTRACT: The metabolic pathway of folate is thought to influence DNA stability either by inducing single/double stranded breaks or by producing low levels of S-adenosyl-methionine leading to abnormal gene expression and chromosome segregation. Polymorphisms in the genes encoding enzymes in the folate metabolism pathway show distinct geographic and/or ethnic variations and in some cases have been linked to disease. Notably, the gene Methylenetetrahydrofolate reductase (MTHFR) in which the homozygous (TT) state of the polymorphism c.665C>T (p.A222V) is associated with reduced specific activity and increased thermolability of the enzyme causing mild hyperhomocysteinemia. Recently several studies have suggested that men carrying this polymorphism may be at increased risk to develop infertility. We have tested this hypothesis in a case/control study of ethnic French individuals. We examined the incidence of polymorphisms in the genes MTHFR (R68Q, A222V and E429A), Methionine synthase reductase MTRR; (I22M and S175L) and Cystathionine beta-synthase (CBS; G307S). The case population consisted of DNA samples from men with unexplained azoospermia (n = 70) or oligozoospermia (n = 182) and the control population consisted of normospermic and fertile men (n = 114). We found no evidence of an association between the incidence of any of these variants and reduced sperm counts. In addition haplotype analysis did not reveal differences between the case and control populations. We could find no evidence for an association between reduced sperm counts and polymorphisms in enzymes involved in folate metabolism in the French population.
  PLoS ONE 01/2009; 4(8):e6540. · 4.09 Impact Factor
• Source

  Available from: Ariane Chapgier

  Article: TLR3 deficiency in patients with herpes simplex encephalitis.

  Shen-Ying Zhang, Emmanuelle Jouanguy, Sophie Ugolini, Asma Smahi, Gaëlle Elain, Pedro Romero, David Segal, Vanessa Sancho-Shimizu, Lazaro Lorenzo, Anne Puel, [......], Bénédicte Héron, Louis Vallée, Lluis Quintana-Murci, Alain Hovnanian, Flore Rozenberg, Eric Vivier, Frédéric Geissmann, Marc Tardieu, Laurent Abel, Jean-Laurent Casanova
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  ABSTRACT: Some Toll and Toll-like receptors (TLRs) provide immunity to experimental infections in animal models, but their contribution to host defense in natural ecosystems is unknown. We report a dominant-negative TLR3 allele in otherwise healthy children with herpes simplex virus 1 (HSV-1) encephalitis. TLR3 is expressed in the central nervous system (CNS), where it is required to control HSV-1, which spreads from the epithelium to the CNS via cranial nerves. TLR3 is also expressed in epithelial and dendritic cells, which apparently use TLR3-independent pathways to prevent further dissemination of HSV-1 and to provide resistance to other pathogens in TLR3-deficient patients. Human TLR3 appears to be redundant in host defense to most microbes but is vital for natural immunity to HSV-1 in the CNS, which suggests that neurotropic viruses have contributed to the evolutionary maintenance of TLR3.
  Science 10/2007; 317(5844):1522-7. · 31.20 Impact Factor