Induction of human aortic myofibroblast-mediated extracellular matrix dysregulation: A potential mechanism of fluoroquinolone-associated aortopathy

Abstract

Objectives: Fluoroquinolone (FQ) antibiotics are associated with adverse aortic clinical events. We assessed human aortic myofibroblast-mediated extracellular matrix (ECM) dysregulation as a possible cellular mechanism underlying FQ-associated aortopathy.

Methods: Human aortic myofibroblasts were isolated from patients with aortopathy undergoing elective ascending aortic resection (N = 9). The capacity for extracellular matrix degradation in cells exposed to FQ was assessed by multiplex analysis of secreted matrix metalloproteinases relative to tissue inhibitors of matrix metalloproteinases (TIMPs). Direct evaluation of extracellular matrix degradation was investigated in human aortic cells using a 3-dimensional gelatin-fluorescein isothiocyanate fluorescence microgel assay. Aortic cellular collagen-1 expression following FQ exposure was determined by immunoblotting and immunofluorescent staining. Cell apoptosis, necrosis, and metabolic viability was determined by annexin-V, propidium iodide staining, and water-soluble tetrazolium salt (WST1) assay.

Results: FQ exposure significantly decreased aortic cell TIMP-1 (P = .004) and TIMP-2 (P = .0004) protein expression compared with vehicle control. The ratio of matrix metalloproteinase-9/TIMP-2 was increased suggesting an increased capacity for extracellular matrix degradation (P = .01). In collagen gels, we show a trend toward increased aortic myofibroblast-mediated collagen fiber degradation with FQ exposure (P = .09). Similarly, FQ exposure attenuated collagen-1 expression as assessed by immunoblotting (P = .002) and immunofluorescence (P = .02). Cell apoptosis, necrosis, and metabolic viability was not significantly influenced by FQ exposure.

Conclusions: For the first time, we document a putative mechanism underlying FQ-associated aortopathy whereby decreased TIMP expression with impaired compensatory collagen-1 expression results in human aortic myofibroblast-mediated extracellular matrix dysregulation. These novel data may provide a cellular and molecular mechanism to explain the established clinical association between FQ exposure and acute aortic events.

Keywords: aortopathy; extracellular matrix; fluoroquinolone.