title: Abnormal methylation of the promoter of CREM is broadly associated with male factor infertility and poor sperm quality but is improved in sperm selected by density gradient centrifugation.
abstract: OBJECTIVE
  To evaluate the methylation status of the promoter of CREM in patients with an abnormal protamine 1/protamine 2 (P1/P2) ratio or oligozoospermia. The effects of density gradient centrifugation and aging of males on CREM promoter methylation were also investigated.
  
  
  METHODS
  Experimental research study.
  
  
  METHODS
  University andrology and research laboratory.
  
  
  METHODS
  Patients with abnormally low (n=24) and high (n=36) P1/P2 ratio; patients with oligozoospermia (n=32); and normozoospermic, fertile controls with normal P1/P2 ratio (n=40).
  
  
  METHODS
  The CpG methyaltion pattern of the promoter of CREM was examined using pyrosequencing.
  
  
  METHODS
  The percentage of methylation of 12 CpGs in the CREM promoter was compared between patients and fertile controls.
  
  
  RESULTS
  There was a significantly higher rate of methylation of CREM in patients with abnormal protamination and oligozoospermia compared with the control group. Sperm concentration, sperm motility, and normal head morphology were negatively correlated with the amount of CpG methylation. Sperm selected from the 90% gradient fraction exhibited less methylation than sperm from the 35% fraction.
  
  
  CONCLUSIONS
  Patients with two types of male factor infertility display an increased abnormal methylation of CREM compared with control subjects. Increased methylation is associated with decreased semen quality, and sperm selected by density gradient centrifugation have less methylation. Further research is necessary to investigate whether epimutations can be found on other nonimprinted gene promoters as well.
authors.affiliation: Department of Surgery, Andrology and IVF Laboratories, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Nanassy
authors.forename: Douglas T
authors.initials: DT
authors.lastname: Carrell
mesh_terms: D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D002499:Centrifugation, Density Gradient; D018899:CpG Islands; D051786:Cyclic AMP Response Element Modulator / Q000235:genetics*; D019175:DNA Methylation; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D009845:Oligospermia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011401:Promoter Regions, Genetic; D011479:Protamines / Q000032:analysis; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000737:chemistry / Q000473:pathology*; D014589:Utah
chemical_list: D015415:Biomarkers; C497410:CREM protein, human; C082073:PRM1 protein, human; D011479:Protamines; C068621:protamine 2; D051786:Cyclic AMP Response Element Modulator