Possible break-down of redox homeostasis in Beals-Hecht syndrome

Beals-Hecht (BH) syndrome is a rare autosomal dominant disorder caused by a mutation of the FBN-2 gene that codifies for fibrillin-2 (FBN-2). Its nosology includes congenital contractural arachnodactyly. The aim of this study was to evaluate the possible breakdown of redox homeostasis in the thoracic aortic aneurysm (TAA) from patients with BH. We determined OS markers such as malondialdehyde (MDA), total antioxidant capacity (TAC), carbonyl groups, glutathione (GSH), thiols the nitrate/nitrite ratio (NO₃^-/NO₂^-) and super oxide radical (O₂^-) by spectrophotometry in homogenized TAA from BH and the ascending fragment of the thoracic aorta (AFTA) from control subjects (CS). We also measured the activities of some of antioxidant enzymes such as GST, GPx, GR and TrxR. The super oxide dismutase (SOD) isoforms, catalase and peroxidase activities were evaluated by native polyacrylamide gels. The activities of the antioxidant enzymes GPx, TrxR, SOD isoforms, catalase and peroxidases were decreased in the TAA from patients with BH (p ≤ 0.04) and the OS markers NO₃^-/NO₂^-, TAC and thiols were decreased(p ≤ 0.04). In addition, O₂^- was increased in patients with BH (p = 0.02). The results suggest a possible loss of redox homeostasis; this loss could be due to the decrease of some of the enzymatic antioxidant system´s enzymes and some antioxidants of the non-enzymatic system. In addition, the decrease in TrxR activity and the concentration of thiol groups could contribute to the alteration and instability of the FBN-2 protein.