title: New immunophenotype of circulating endothelial progenitor cells and endothelial microparticles in patients with erectile dysfunction and metabolic syndrome: effects of tadalafil administration.
abstract: OBJECTIVE
  Circulating endothelial progenitor cells (EPCs) and endothelial microparticles (EMPs) increase, respectively, in the attempt to repair the damaged endothelium and in response to endothelial dysfunction. Erectile dysfunction (ED) of arterial origin recognizes endothelial dysfunction as one of its main determinants and shares risk factors and physiopathological evolution with the metabolic syndrome (MetS). Tadalafil, selective inhibitor of phosphodiesterase V, long half-life, is used to treat erectile dysfunction, and several studies have already documented the beneficial effects on endothelial dysfunction. The aim of this paper was to evaluate the concentrations of EPCs and EMPs in patients with arterial ED and MetS, before and after tadalafil administration, and in healthy men.
  
  
  METHODS
  Thirty patients (47-54 years) with ED and MetS (ATP III 1999 criteria) and 17 healthy men (44-57 years) were selected. EPCs (CD45neg/CD34pos/CD144pos) and EMPs (CD45neg/CD34neg/CD144pos) blood concentrations were evaluated by flow cytometry before and after administration of tadalafil (20 mg) on demand for 3 months. After treatment, the patients were divided into responders and poor responders, according to their IIEF-5 score.
  
  
  METHODS
  Blood EPCs and EMPs.
  
  
  RESULTS
  Before treatment, the percentage of EPCs and EMPs was significantly higher in patients with ED and MetS compared to healthy men. Treatment with tadalafil increased significantly EPCs in both responders and poor responders. The latter had significantly higher EPCs compared to responders, both before and after tadalafil. Before tadalafil, EMPs were higher, but not significantly, in poor responders vs. responders. No significant change occurred after tadalafil administration in both responders and poor responders. A significant positive correlation was found between EPCs and age, Body Mass Index (BMI), acceleration time, IMT and EDV; whereas a negative correlation was found with IIEF-5 score, PSV and resistance index. EMPs correlated positively with BMI, acceleration time and IMT and negatively with the IIEF-5 score.
  
  
  CONCLUSIONS
  Tadalafil increased the percentage of EPCs in both responders and poor responders, suggesting the persistence of an adequate bone marrow response. The unchanged EMP concentrations after tadalafil suggest a reduction of the dysfunctional mechanism.
authors.affiliation: Section of Endocrinology, Andrology and Internal Medicine, Human Reproduction and Biotechnology Sciences, Department of Internal Medicine and Systemic Diseases, University of Catania, Catania, Italy. sandrolavignera@email.it
authors.forename: S
authors.initials: S
authors.lastname: La Vignera
mesh_terms: D000704:Analysis of Variance; D015703:Antigens, CD / Q000097:blood*; D018952:Antigens, CD34 / Q000097:blood; D015820:Cadherins / Q000097:blood; D002243:Carbolines / Q000627:therapeutic use*; D055252:Cell-Derived Microparticles / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D042783:Endothelial Cells / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D018783:Impotence, Vasculogenic / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D007558:Italy; D017493:Leukocyte Common Antigens / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000276:immunology* / Q000473:pathology; D008875:Middle Aged; D010641:Phenotype; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D013234:Stem Cells / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D000068581:Tadalafil; D016896:Treatment Outcome; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015820:Cadherins; D002243:Carbolines; D017493:Leukocyte Common Antigens; D058986:Phosphodiesterase 5 Inhibitors; D000068581:Tadalafil; D000099152:Cadherin 5; C516769:PTPRC protein, human