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We studied circulating levels of endothelin-1, catecholamines and nitric oxide after a mental arithmetic test in 14 patients with early ischemic lesions of the extremities due to systemic sclerosis and slightly impaired peripheral vascular flow. The test induced an increase (P < 0.01) in blood pressure, heart rate, endothelin-1 and catecholamine levels, whereas it did not change the low basal levels of nitric oxide. In healthy subjects (n = 20) the test significantly (P < 0.01) decreased endothelin-1 without affecting nitric oxide. The low basal levels of nitric oxide and the high plasma concentration of endothelin-1 after psychological stress cannot be explained by an impaired release from the limited ischemic lesions alone. This suggests a diffuse microvascular derangement that aggravates the course of peripheral microvascular ischemic lesions.

Much evidence in the literature demonstrates the effect of cyclic mechanical stretch in maintaining, or addressing, a muscle phenotype. Such results were obtained using several technical approaches, useful for the experimental collection of proofs of principle but probably unsuitable for application in clinical regenerative medicine. Here we aimed to design a reliable innovative bioreactor, acting as a stand-alone cell culture incubator, easy to operate and effective in addressing mesenchymal stem cells (MSCs) seeded onto a 3D bioreabsorbable scaffold, towards a muscle phenotype via the transfer of a controlled and highly-reproducible cyclic deformation. Electron microscopy, immunohistochemistry and biochemical analysis of the obtained pseudotissue constructs showed that cells 'trained' over 1 week: (a) displayed multilayer organization and invaded the 3D mesh of the scaffold; and (b) expressed typical markers of muscle cells. This effect was due only to physical stimulation of the cells, without the need of any other chemical or genetic manipulation. This device is thus proposed as a prototypal instrument to obtain pseudotissue constructs to test in cardiovascular regenerative medicine, using good manufacturing procedures.

Adipose-derived stem cells (ADSCs) are stromal mesenchymal stem cells isolated from lipoaspirates, and they display a broad potential to differentiate toward different lineages. The role of epigenetics in regulating the expression of their lineage-specific genes is under evaluation, however till date virtually nothing is known about the relative significance of cardiac-specific transcription factor genes in human ADSCs. The aim of this study was to investigate DNA promoter methylation and relevant histone modifications involving MEF-2C, GATA-4, and Nkx2.5 in native human ADSCs. CpG sites at the transcription start in their promoters were found unmethylated using methylation-specific PCR. Chromatin immunoprecipitation assay showed low levels of total acetylated H3 histone (acH3) and high levels of trimethylated lysine 27 in H3 histone (H3K27me3) which were associated with both GATA-4 and Nkx2.5 promoters, indicating their transcriptional repressive chromatin arrangement. On the other hand, the opposite was apparent for MEF-2C promoter. Accordingly, MEF-2C—but not GATA-4 and Nkx2.5— transcripts were evidenced in native human ADSCs. These results suggest that the chromatin arrangement of these early cardiac regulatory genes could be explored as a level of intervention to address the differentiation of human ADSCs toward the cardiac lineage.

Twelve patients with chronic critical limb ischemia in whom a spinal cord stimulation (SCS) system had been implanted for at least one year had increased microvascular flow and achieved healing of trophic acral lesions. After switching off the system, the clinical improvement persisted for 10 days and the neurohormonal pattern showed high plasma values of beta-endorphin and Met-enkephalin, normal dynorphin B, endothelin-1 and catecholamines, and low nitric oxide. Met-enkephalin levels were further increased (P < 0.01) immediately after switching on the electrical stimulation again. The persistence of high plasma opioid levels after switching off the spinal cord stimulation explains the absence of subjective complaints and suggests an involvement of opioids in the regulation and improvement of the microcirculation.