title: The Probiotic Mixture VSL#3 Alters the Morphology and Secretion Profile of Both Polarized and Unpolarized Human Macrophages in a Polarization-Dependent Manner.
abstract: BACKGROUND
  Patients with Inflammatory Bowel Disease (IBD), most commonly Crohn's disease (CD) or ulcerative colitis (UC), suffer from chronic intestinal inflammation of unknown etiology. Increased proinflammatory macrophages (M1) have been documented in tissue from patients with CD. Anti-inflammatory macrophages (M2) may play a role in UC given the preponderance of Th2 cytokines in this variant of IBD. Animal and clinical studies have shown that the probiotic VSL#3 can ameliorate signs and symptoms of IBD. Although animal data suggests a modulatory effect on macrophage phenotype, the effect of VSL#3 on human macrophages remains unknown.
  
  
  OBJECTIVE
  To determine the effect of the probiotic VSL#3 on the phenotype of polarized (M1/M2) and unpolarized (MΦ) human macrophages.
  
  
  METHODS
  Human monocyte-derived macrophages, generated by culturing monocytes with M-CSF, were left unpolarized or were polarized towards an M1 or an M2 phenotype by culture with LPS and IFN-γ or IL-4, respectively, and were then cultured in the presence or absence of VSL#3 for 3 days. Changes in macrophage morphology were assessed. Cytokine and chemokine levels in supernatants were determined by multiplex assay.
  
  
  RESULTS
  VSL#3 decreased the granuloma-like aggregates of M1 macrophages, increased fibroblast-like M2 macrophages, and decreased fibroblast-like MΦ macrophages. VSL#3 increased the secretion of IL-1β, IL-6, IL-10, and G-CSF by M1, M2, and MΦ macrophages. VSL#3 exposure maintained the proinflammatory phenotype of M1 macrophages, sustaining IL-12 secretion, increasing IL-23 secretion, and decreasing MDC secretion. Both VSL#3-treated M2 and MΦ macrophages secreted higher levels of anti-inflammatory and pro-healing factors such as IL-1Ra, IL-13, EGF, FGF-2, TGF-α, and VEGF, as well as proinflammatory cytokines, including IL-12 and TNF-α.
  
  
  CONCLUSIONS
  Under our experimental conditions VSL#3 induced a mixed proinflammatory and anti-inflammatory phenotype in polarized and unpolarized macrophages. This differential effect could explain why patients with CD do not respond to probiotic therapy as well as patients with UC.
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Isidro
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Bonilla
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Hendrick
authors.initials: H
authors.lastname: Pagan
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Myrella L
authors.initials: ML
authors.lastname: Cruz
authors.affiliation: Department of Microbiology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Pablo
authors.initials: P
authors.lastname: Lopez
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Lenin
authors.initials: L
authors.lastname: Godoy
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Siomara
authors.initials: S
authors.lastname: Hernandez
authors.affiliation: Department of Biochemistry, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Raisa Y
authors.initials: RY
authors.lastname: Loucil-Alicea
authors.affiliation: Department of Microbiology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Rivera-Amill
authors.affiliation: Department of Microbiology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamamura
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA ; Department of Pathology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Angel A
authors.initials: AA
authors.lastname: Isidro
authors.affiliation: Department of Physiology and Pharmacology, Ponce School of Medicine and Health Sciences, Ponce, PR 00716, USA.
authors.forename: Caroline B
authors.initials: CB
authors.lastname: Appleyard
keywords: Crohn’s disease; Inflammatory bowel disease; M1; M2; Probiotic; Ulcerative colitis; VSL#3; macrophage