Serum Amyloid P Contained in Alveolar Fluid From Patients With Acute Respiratory Distress Syndrome Mediates the Inhibition of Monocyte Differentiation into Fibrocyte. Issue 7 (July 2016)

• Record Type: Journal Article
• Authors: Garnier, Marc; Mailleux, Arnaud A.; Besnard, Valérie; Abback, Paer S.; Leçon, Véronique; Neuville, Mathilde; Gouel, Aurélie; Crestani, Bruno; Dehoux, Monique; Quesnel, Christophe
• Is Part Of: Critical care medicine. Volume 44:Issue 7(2016)
• Publication Date: 2016-07
• Subjects: acute respiratory distress syndrome -- fibrocyte -- monocyte -- peripheral blood mononuclear cell -- serum amyloid P; Critical care medicine -- Periodicals; Soins intensifs -- Périodiques; 616.028
• DOI: 10.1097/CCM.0000000000001612
• Languages: English
• ISSNs: 0090-3493

Abstract

Abstract : Objective: Alveolar fibrocytes are monocyte-derived mesenchymal cells associated with poor prognosis in patients with acute respiratory distress syndrome. Our aims were to determine the following: 1) the ability of monocytes from acute respiratory distress syndrome patients to differentiate into fibrocytes; 2) the influence of the acute respiratory distress syndrome alveolar environment on fibrocyte differentiation; and 3) mediators involved in this modulation, focusing on serum amyloid P. Design: Experimental in vitro investigation. Setting: Two ICUs of a teaching hospital. Patients: Twenty-five patients (19 mild-to-severe acute respiratory distress syndrome and six matched ventilated controls without acute respiratory distress syndrome) were enrolled. Six healthy volunteers served as non-ventilated controls. Interventions: Peripheral blood mononuclear cells were isolated from acute respiratory distress syndrome, ventilated controls, and non-ventilated controls blood and cultured in vitro. Fibrocytes were counted at basal condition and after culture with broncho-alveolar lavage fluid. Plasma and broncho-alveolar lavage fluid serum amyloid P contents were determined by western blot and enzyme-linked immunosorbent assay. Serum amyloid P was located in normal and acute respiratory distress syndrome lung by immunohistochemistry. Measurements and Main Results: Acute respiratory distress syndrome peripheral blood mononuclear cells had a three-fold increased ability to differentiate into fibrocytes compared to ventilated controls or non-ventilated controls. Acute respiratory distress syndrome broncho-alveolar lavage fluid inhibited by 71% (55–94) fibrocyte differentiation compared to saline control. Ventilated controls' broncho-alveolar lavage fluid was a less potent inhibitor (51% [23–66%] of inhibition), whereas non-ventilated controls' broncho-alveolar lavage fluid had no effect on fibrocyte differentiation. Serum amyloid P concentration was decreased in plasma and dramatically increased in broncho-alveolar lavage fluid during acute respiratory distress syndrome. Alveolar serum amyloid P originated, in part, from the release of serum amyloid P associated with lung connective tissue during acute respiratory distress syndrome. Serum amyloid P depletion decreased the inhibitory effect of acute respiratory distress syndrome broncho-alveolar lavage fluid by 60%, whereas serum amyloid P replenishment of serum amyloid P-depleted acute respiratory distress syndrome broncho-alveolar lavage fluid restored their full inhibitory effect. Conclusions: The presence of fibrocytes in the lung during acute respiratory distress syndrome could result in a balance between higher ability of monocytes to differentiate into fibrocytes and the inhibitory effect of the alveolar environment, mainly dependent on serum amyloid P. Abstract : Supplemental Digital Content is available in the text.