Cumulative radiation exposure during thoracic endovascular aneurysm repair and subsequent follow-up

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miR-34a Promotes Vascular Smooth Muscle Cell Calcification by Downregulating SIRT1 (Sirtuin 1) and Axl (AXL Receptor Tyrosine Kinase).

Objective- Vascular calcification (VC) is age dependent and a risk factor for cardiovascular and all-cause mortality. VC involves the senescence-induced transdifferentiation of vascular smooth muscle cells (SMCs) toward an osteochondrogenic lineage resulting in arterial wall mineralization. miR-34a increases with age in aortas and induces vascular SMC senescence through the modulation of its target SIRT1 (sirtuin 1). In this study, we aimed to investigate whether miR-34a regulates VC. Approach and Results- We found that miR-34a and Runx2 (Runt-related transcription factor 2) expression correlates in young and old mice. Mir34a <sup>+/+</sup> and Mir34a <sup>-/-</sup> mice were treated with vitamin D, and calcium quantification revealed that Mir34a deficiency reduces soft tissue and aorta medial calcification and the upregulation of the VC Sox9 (SRY [sex-determining region Y]-box 9) and Runx2 and the senescence p16 and p21 markers. In this model, miR-34a upregulation was transient and preceded aorta mineralization. Mir34a <sup>-/-</sup> SMCs were less prone to undergo senescence and under osteogenic conditions deposited less calcium compared with Mir34a <sup>+/+</sup> cells. Furthermore, unlike in Mir34a <sup>+/+</sup> SMC, the known VC inhibitors SIRT1 and Axl (AXL receptor tyrosine kinase) were only partially downregulated in calcifying Mir34a <sup>-/-</sup> SMC. Strikingly, constitutive miR-34a overexpression to senescence-like levels in human aortic SMCs increased calcium deposition and enhanced Axl and SIRT1 decrease during calcification. Notably, we also showed that miR-34a directly decreased Axl expression in human aortic SMC, and restoration of its levels partially rescued miR-34a-dependent growth arrest. Conclusions- miR-34a promotes VC via vascular SMC mineralization by inhibiting cell proliferation and inducing senescence through direct Axl and SIRT1 downregulation, respectively. This miRNA could be a good therapeutic target for the treatment of VC

Coronary artery mechanics induces human saphenous vein remodelling via recruitment of adventitial myofibroblast-like cells mediated by Thrombospondin-1

Rationale: Despite the preferred application of arterial conduits, the greater saphenous vein (SV) remains indispensable for coronary bypass grafting (CABG), especially in multi-vessel coronary artery disease (CAD). The objective of the present work was to address the role of mechanical forces in the activation of maladaptive vein bypass remodeling, a process determining progressive occlusion and recurrence of ischemic heart disease. Methods: We employed a custom bioreactor to mimic the coronary shear and wall mechanics in human SV vascular conduits and reproduce experimentally the biomechanical conditions of coronary grafting and analyzed vein remodeling process by histology, histochemistry and immunofluorescence. We also subjected vein-derived cells to cyclic uniaxial mechanical stimulation in culture, followed by phenotypic and molecular characterization using RNA and proteomic methods. We finally validated our results in vitro and using a model of SV carotid interposition in pigs. Results: Exposure to pulsatile flow determined a remodeling process of the vascular wall involving reduction in media thickness. Smooth muscle cells (SMCs) underwent conversion from contractile to synthetic phenotype. A time-dependent increase in proliferating cells expressing mesenchymal (CD44) and early SMC (SM22\u3b1) markers, apparently recruited from the SV adventitia, was observed especially in CABG-stimulated vessels. Mechanically stimulated SMCs underwent transition from contractile to synthetic phenotype. MALDI-TOF-based secretome analysis revealed a consistent release of Thrombospondin-1 (TSP-1), a matricellular protein involved in TGF-\u3b2-dependent signaling. TSP-1 had a direct chemotactic effect on SV adventitia resident progenitors (SVPs); this effects was inhibited by blocking TSP-1 receptor CD47. The involvement of TSP-1 in adventitial progenitor cells differentiation and graft intima hyperplasia was finally contextualized in the TGF-\u3b2-dependent pathway, and validated in a saphenous vein into carotid interposition pig model. Conclusions: Our results provide the evidence of a matricellular mechanism involved in the human vein arterialization process controlled by alterations in tissue mechanics, and open the way to novel potential strategies to block VGD progression based on targeting cell mechanosensing-related effectors

Aloe barbadensis: how a miraculous plant becomes reality

Aloe barbadensis Miller is a plant that is native to North and East Africa and has accompanied man for over 5,000 years. The aloe vera plant has been endowed with digestive, dermatological, culinary and cosmetic virtues. On this basis, aloe provides a range of possibilities for fascinating studies from several points of view, including the analysis of chemical composition, the biochemistry involved in various activities and its application in pharmacology, as well as from horticultural and economic standpoints. The use of aloe vera as a medicinal plant is mentioned in numerous ancient texts such as the Bible. This multitude of medicinal uses has been described and discussed for centuries, thus transforming this miracle plant into reality. A summary of the historical uses, chemical composition and biological activities of this species is presented in this review. The latest clinical studies involved in vivo and in vitro assays conducted with aloe vera gel or its metabolites and the results of these studies are reviewed

MLPA-based copy number variation analysis in patients with Abdominal Aortic Aneurysm: identification of a novel mutation in the human TGFbeta-R1 gene

Background. Abdominal aortic aneurysm (AAA) is a multifactorial condition associated with a strong genetic component. The transforming growth factor beta (TGFB) signalling pathway regulates several cell functions including proliferation, differentiation and vascular remodelling. TGFB receptor 1 and 2 (TGFBR1 and TGFBR2) gene sequencing identified point mutations associated with AAA manifestation. Whether heterozygous exon deletions and duplications may also be associated with AAA is presently unknown. Aim. To screen TGFBR1 and TGFBR2 genes for genomic rearrangements, in a cohort of AAA patients, by using the Multiplex Ligation-dependent Probe Amplification (MLPA) technique. Methods. 50 patients undergoing elective open AAA repair referred to the Unit of Vascular Surgery of the Centro Cardiologico Monzino were enrolled. Genomic DNA was extracted from peripheral blood and MLPA analysis was performed by using an ordinary PCR thermal cycler for the hybridization and amplification steps, and a capillary sequencer for amplicons separation. TGFBR1 protein levels in tissue samples collected during surgery from aneurysmatic abdominal aortic wall were assessed by western blot. Results. MLPA identified a new mutation in TGFBR1, consisting of a heterozygous deletion of exon 1 and 2, encoding for the receptor extracellular domain, and partially of the promoter region, in one out of the 50 patients screened. This mutation does not affect the protein expression levels, which were comparable to those detected in AAA patients who did not carry the new mutation. No rearrangements were identified in the TGFBR2 gene. Conclusions Application of the MLPA analysis to the screening of novel genomic rearrangements allowed the identification of a new heterozygous deletion in the TGFBR1 gene in a patient affected by AAA. Whether this mutation may affect the receptor functional activity, despite the apparently unaltered TGFBR1 protein levels, is currently matter of ongoing investigations

MLPA-BASED COPY NUMBER VARIATION ANALYSIS IN PATIENTS WITH ABDOMINAL AORTIC ANEURYSM: IDENTIFICATION OF A NOVEL MUTATION IN THE HUMAN TGF\u3b2-R1 GENE

Background Abdominal aortic aneurysm (AAA) is a multifactorial condition associated with a strong genetic component. The transforming growth factor \u3b2 (TGF\u3b2) signalling pathway regulates several cell functions including proliferation, differentiation and vascular remodelling. TGF\u3b2 receptor 1 and 2 (TGF\u3b2R1 and TGF\u3b2R2) gene sequencing identified point mutations associated with AAA manifestation. Whether heterozygous exon deletions and duplications may also be associated with AAA is presently unknown. Aim To screen TGF\u3b2R1 and TGF\u3b2R2 genes for genomic rearrangements, in a cohort of AAA patients, by using the Multiplex Ligation-dependent Probe Amplification (MLPA) technique. Methods 50 patients undergoing elective open AAA repair referred to the Unit of Vascular Surgery of the Centro Cardiologico Monzino were enrolled. Genomic DNA was extracted from peripheral blood and MLPA analysis was performed by using an ordinary PCR thermal cycler for the hybridization and amplification steps, and a capillary sequencer for amplicons separation. TGF\u3b2R1 protein levels in tissue samples collected during surgery from aneurysmatic abdominal aortic wall were assessed by western blot. Results MLPA identified a new mutation in TGF\u3b2R1, consisting of a heterozygous deletion of exon 1 and 2, encoding for the receptor extracellular domain, and partially of the promoter region, in one out of the 50 patients screened. This mutation does not affect the protein expression levels, which were comparable to those detected in AAA patients who did not carry the new mutation. No rearrangements were identified in the TGF\u3b2R2 gene. Conclusions Application of the MLPA analysis to the screening of novel genomic rearrangements allowed the identification of a new heterozygous deletion in the TGF\u3b2R1 gene in a patient affected by AAA. Whether this mutation may affect the receptor functional activity, despite the apparently unaltered TGF\u3b2R1 protein levels, is currently matter of ongoing investigations

Tissue factor and atherosclerosis: not only vessel wall-derived TF, but also platelet-associated TF

In the last ten years the contribution of both vessel wall-derived tissue factor (TF) and platelets to atherosclerosis has been revisited. At the beginning of the 2000 a circulating blood-borne TF has been proposed to sustain coagulation activation and propagation on the edge of a growing thrombus. Concomitantly with the observation that platelets not only contribute to thrombus formation, but also take part to the onset of the atherosclerotic lesion, evidences have been provided that they express functionally active TF, making them able to trigger the coagulation cascade