title: mRNA levels of low-density lipoprotein receptors are overexpressed in the foci of deep bowel endometriosis.
abstract: Is mRNA expression of LDL receptors altered in deep bowel endometriotic foci? SUMMARY ANSWER: mRNA expression of LDL receptors is up-regulated in deep bowel endometriotic foci of patients with endometriosis.
  
  
  
  Several studies have demonstrated the overexpression of low-density lipoprotein receptors in various tumour cell lines and endometriosis has similar aspects to cancer, mainly concerning the pathogenesis of both diseases. This is the first study we know of to investigate lipoprotein receptors expression in deep endometriosis with bowel involvement.
  
  
  
  During 2014-2015, an exploratory case-control study was conducted with 39 patients, including 20 women with a histological diagnosis of deep endometriosis compromising the bowel and 19 women without endometriosis who underwent laparoscopic tubal ligation.
  
  
  
  Peripheral blood samples were collected on the day of surgery for lipid profile analysis, and samples of endometrial tissue and of bowel endometriotic lesions were also collected. The tissue samples were sent for histopathological analysis and for LDL-R and LRP-1 gene expression screening using quantitative real-time PCR.
  
  
  
  Patients with deep endometriosis had lower LDL-cholesterol than patients without the disease (119 ± 23 versus 156 ± 35; P = 0.001). Gene expression analysis of LDL receptors revealed that LDL-R was more highly expressed in endometriotic lesions when compared to the endometrium of the same patient but not more than in the endometrium of women without endometriosis (0.027 ± 0.022 versus 0.012 ± 0.009 versus 0.019 ± 0.01, respectively; P < 0.001). LRP-1 was more highly expressed in endometriotic lesions, both when compared with the endometrium of the same patient and when compared with the endometrium of patients without the disease (0.307 ± 0.207 versus 0.089 ± 0.076 and versus 0.126 ± 0.072, respectively; P < 0.001). The study also showed that LDL-R gene expression in the endometrium of women with endometriosis was higher during the secretory phase of the menstrual cycle (P = 0.001). LRP-1 gene expression was increased during the secretory phase in the endometrium of women without the disease (P = 0.008).
  
  
  
  In the endometriotic lesions, the presence of fibrosis is substantial, restricting access to the stromal and glandular components of the lesion. Despite that, we found that LDL receptor mRNA was overexpressed. Future studies may perform laser microdissection to isolate the area of interest in the target tissue, excluding fibrosis contamination.
  
  
  
  This study supports the feasibility of LDL-R targeted therapy in the treatment of deep endometriosis.
  
  
  
  This study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP #2011/17245-0). The authors have no conflicts of interest to declare.
authors.affiliation: Gynaecological Endoscopy Center of the Perola Byington Hospital Reference Center for Women's Health, CEP: 01317-000, São Paulo, SP, Brazil gibran.luciano@gmail.com.|Obstetrics and Gynaecology Department, University of São Paulo Medical School, CEP: 05403-000, São Paulo, SP, Brazil.
authors.forename: Luciano
authors.initials: L
authors.lastname: Gibran
authors.affiliation: Lipid Metabolism Laboratory of the Heart Institute of the Hospital das Clínicas, University of São Paulo Medical School, CEP: 05403-000, São Paulo, SP, Brazil.|Faculty of Pharmaceutical Sciences, University of São Paulo, CEP: 05508-000, São Paulo, SP, Brazil.
authors.forename: Raul C
authors.initials: RC
authors.lastname: Maranhão
authors.affiliation: Lipid Metabolism Laboratory of the Heart Institute of the Hospital das Clínicas, University of São Paulo Medical School, CEP: 05403-000, São Paulo, SP, Brazil.
authors.forename: Elaine R
authors.initials: ER
authors.lastname: Tavares
authors.affiliation: Lipid Metabolism Laboratory of the Heart Institute of the Hospital das Clínicas, University of São Paulo Medical School, CEP: 05403-000, São Paulo, SP, Brazil.
authors.forename: Priscila O
authors.initials: PO
authors.lastname: Carvalho
authors.affiliation: Obstetrics and Gynaecology Department, University of São Paulo Medical School, CEP: 05403-000, São Paulo, SP, Brazil.
authors.forename: Maurício S
authors.initials: MS
authors.lastname: Abrão
authors.affiliation: Obstetrics and Gynaecology Department, University of São Paulo Medical School, CEP: 05403-000, São Paulo, SP, Brazil.|Jewish Teaching and Research Institute, Albert Einstein Hospital, CEP: 05652-000, São Paulo, SP, Brazil.
authors.forename: Sergio
authors.initials: S
authors.lastname: Podgaec
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004715:Endometriosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007410:Intestinal Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; D011973:Receptors, LDL
keywords: Low Density Lipoprotein Receptor-Related Protein 1; cholesterol, LDL; endometriosis; nanoparticles; receptors, LDL