Oxidant/Antioxidant Profile in the Thoracic Aneurysm of Patients with the Loeys-Dietz Syndrome.

Patients with the Loeys-Dietz syndrome (LDS) have mutations in the TGF-ßR1, TGF-ßR2, and SMAD3 genes. However, little is known about the redox homeostasis in the thoracic aortic aneurysms (TAA) they develop. Here, we evaluate the oxidant/antioxidant profile in the TAA tissue from LDS patients and compare it with that in nondamaged aortic tissue from control (C) subjects. We evaluate the enzymatic activities of glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) isoforms, and thioredoxin reductase (TrxR). We also analyze some antioxidants from a nonenzymatic system such as selenium (Se), glutathione (GSH), and total antioxidant capacity (TAC). Oxidative stress markers such as lipid peroxidation and carbonylation, as well as xanthine oxidase (ORX) and nuclear factor erythroid 2-related factor 2 (Nrf2) expressions, were also evaluated. TAA from LDS patients showed a decrease in GSH, Se, TAC, GPx, GST, CAT, and TrxR. The SOD activity and ORX expressions were increased, but the Nrf2 expression was decreased. The results suggest that the redox homeostasis is altered in the TAA from LDS patients, favoring ROS overproduction that contributes to the decrease in GSH and TAC and leads to LPO and carbonylation. The decrease in Se and Nrf2 alters the activity and/or expression of some antioxidant enzymes, thus favoring a positive feedback oxidative background that contributes to the TAA formation.

Genomic Observations of a Rare/Pathogenic SMAD3 Variant in Loeys⁻Dietz Syndrome 3 Confirmed by Protein Informatics and Structural Investigations.

Background and objectives: Loeys-Dietz syndrome 3, also known as aneurysms--osteoarthritis syndrome, is an autosomal dominant genetic connective tissue disease caused by pathogenic variants in SMAD3, a transcription factor involved in TGF-ß signaling. This disorder is characterized by early-onset osteoarthritis and arterial aneurysms. Common features include scoliosis, uvula abnormalities, striae, and velvety skin. Materials and Methods: The pathogenicity of a variant of uncertain significance in the SMAD3 gene was evaluated (variant c.220C > T) through personalized protein informatics and molecular studies. Results: The case of a 44-year-old male, who was originally presumed to have Marfan syndrome, is presented. An expanded gene panel determined the probable cause to be a variant in SMAD3, c.220C > T (p.R74W). His case was complicated by a history of stroke, but his phenotype was otherwise characteristic for Loeys-Dietz syndrome 3. Conclusion: This case emphasizes the importance of comprehensive genetic testing to evaluate patients for connective tissue disorders, as well as the potential benefit of utilizing a protein informatics platform for the assessment of variant pathogenicity.

Three Novel Mutations in FBN1 and TGFBR2 in Patients with the Syndromic Form of Thoracic Aortic Aneurysms and Dissections.

There are many inherited disorders associated with thoracic aortic aneurysms and dissections (TAADs), like Marfan syndrome and Loeys-Dietz syndrome (LDS). The 4 patients in this study all had TAADs and were initially diagnosed with suspected Marfan syndrome. We collected peripheral blood samples from the patients and their family members and then attempted to identify the causal mutation using different methods including PCR, Sanger sequencing, and next generation sequencing. We identified 3 novel heterozygous mutations including 2 splicing mutations of FBN1 and 1 missense mutation of TGFBR2 in our patients. Although these mutation sites have been reported in the Human Gene Mutation Database, the nucleotide changes are different. All novel mutations found in this study were confirmed to be absent in 50 unrelated normal individuals of the same ethnic background. The RT-PCR results of 2 splicing mutations verified that the mutations can lead to the skipping of exons. The RT-qPCR results indicated that FBN1 mRNA levels were nearly 50 percent lower in the patients than in normal controls, indicating that there is almost no expression of truncated fibrillin-1 because of the nonsense-mediated mRNA decay (NMD) mechanism. To the best of our knowledge, we are the first to report these 3 novel mutations. However, the pathogenicity of these mutations still needs further confirmation. Our study has confirmed or corrected the clinical diagnosis, and enlarged the mutation spectrum of FBN1 and TGFBR2. The results should be helpful for prenatal diagnosis and genetic counseling.

Long noncoding RNA AK056155 involved in the development of Loeys-Dietz syndrome through AKT/PI3K signaling pathway.

Loeys-Dietz syndrome (LDS) is an autosomal dominant genetic connective tissue disorder, and most of LDS patients will develop into aortic aneurysm. Unfortunately, there is no known cure, and a high risk of death from aortic aneurysm rupture. However the detailed mechanism is still unknown. In order to explore the mechanism, we firstly used bioinformatics to predict, and then verified with biology methods. Firstly, we found that LncRNA AK056155 was differentially expressed in peripheral blood circulating endothelial cells between normal patients and LDS patients by bioinformatics. Then we further verified that AK056155 was also overexpressed in aortic aneurysm patients by RT-PCR. Moreover, we demonstrated that the expression of AK056155 can be enhanced by TGF-ß1 in a concentration or time depended manner in HUVECs by RT-PCR. Furthermore, the expression of AK056155 was reduced with treatment of PI3K inhibitor (LY294002) or AKT inhibitor (GDC-0068) in combination with TGF-ß1. These results indicate that AK056155 involved in the development of Loeys-Dietz syndrome through AKT/PI3K signaling pathway, it may provide a promising target gene to prevent LDS develop in to aortic aneurysm.

Reversible cerebral vasoconstriction syndrome and posterior reversible encephalopathy syndrome in a boy with Loeys-Dietz syndrome.

Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder, caused by heterozygous mutations in TGFBR1 or TGFBR2 and characterized by vascular complications (cerebral, thoracic, and abdominal arterial aneurysms and/or dissections) and skeletal manifestations. We here report the first patient with LDS presenting with reversible cerebral vasoconstriction syndrome (RCVS), a clinico-radiological condition characterized by recurrent thunderclap headaches, with or without neurological symptoms, and reversible vasoconstriction of cerebral arteries. The patient was a 9-year-old boy with a heterozygous TGFBR2 mutation, manifesting camptodactyly, talipes equinovarus, and lamboid craniosynostosis. He complained of severe recurrent headaches 2 months after total aortic replacement for aortic root dilatation and a massive Stanford type B aortic dissection. A thoracic CT scan revealed a left subclavian artery dissection. Brain MRI and MRA detected bilateral internal carotid artery constriction along with a cortical subarachnoid hemorrhage without intracranial aneurysms. Subsequently, he developed visual disturbance and a generalized seizure associated with multiple legions of cortical and subcortical increased signals including the left posterior lobe, consistent with posterior reversible encephalopathy syndrome (PRES), a condition characterized by headaches, visual disorders, seizures, altered mentation, consciousness disturbances, focal neurological signs, and vasogenic edema predominantly in the white matter of the posterior lobe. Vasoconstriction of the internal carotid artery was undetectable 2 months later, and he was diagnosed as having RCVS. Endothelial dysfunction, associated with impaired TGF-ß signaling, might have been attributable to the development of RCVS and PRES.

Total serum transforming growth factor-ß1 is elevated in the entire spectrum of genetic aortic syndromes.

BACKGROUND: Total serum transforming growth factor-beta 1 (tsTGF-ß1) is increased in patients with Marfan syndrome (MFS), but it has not been assessed in thoracic aortic aneurysm and dissection (TAAD), Loeys-Dietz syndrome (LDS), and bicuspid aortic valve disease (BAVD). HYPOTHESIS: tsTGF-ß1 is increased in genetic aortic syndromes including TAAD, LDS, MFS, and BAVD. METHODS: We measured tsTGF-ß1 and performed sequencing of the genes FBN1, TGFBR1, and TGFBR2 in 317 consecutive patients with suspected or known genetic aortic syndrome (167 men, 150 women; mean age 43 ± 14 years). TAAD was diagnosed in 20, LDS in 20, MFS in 128, and BAVD in 30 patients, and genetic aortic syndrome was excluded in 119 patients. RESULTS: Elevated tsTGF-ß1 levels were associated with causative gene mutations (P = 0.008), genetic aortic syndrome (P = 0.009), and sporadic occurrence of genetic aortic syndrome (P = 0.048), whereas only genetic aortic syndrome qualified as an independent predictor of tsTGF-ß1 (P = 0.001). The tsTGF-ß1 levels were elevated in FBN1 and NOTCH1 mutations vs patients without mutations (both P = 0.004), and in NOTCH1 mutations vs ACTA2/MYH11 mutations (P = 0.015). Similarly, tsTGF-ß1 levels were elevated in MFS (P = 0.003) and in BAVD (P = 0.006) vs patients without genetic aortic syndrome. In contrast to specific clinical features of MFS, FBN1 in-frame mutations (P = 0.019) were associated with increased tsTGF-ß1 levels. CONCLUSIONS: tsTGF-ß1 is elevated in the entire spectrum of genetic aortic syndromes. However, gradual differences in the increases of tsTGF-ß1 levels may mirror different degrees of alteration of tsTGF-ß1 signaling in different genetic aortic syndromes.

Severe eczema and Hyper-IgE in Loeys-Dietz-syndrome - contribution to new findings of immune dysregulation in connective tissue disorders.

Loeys-Dietz syndrome (LDS) is a connective tissue disorder caused by monoallelic mutations in TGFBR1 and TGFBR2, which encode for subunits of the transforming growth factor beta (TGFß) receptor. Affected patients are identified by vascular aneurysms with tortuosity and distinct morphological presentations similar to Marfan syndrome; however, an additional predisposition towards asthma and allergy has recently been found. We describe two patients with a novel missense mutation in TGFBR1 presenting with highly elevated levels of IgE and severe eczema similar to autosomal-dominant Hyper-IgE syndrome (HIES). Mild allergic manifestations with normal up to moderately increased IgE were observed in 3 out of 6 additional LDS patients. A comparison of this cohort with 4 HIES patients illustrates the significant overlap of both syndromes including eczema and elevated IgE as well as skeletal and connective tissue manifestations.