Stem cell populations in the heart and the role of Isl1 positive cells

Cardiac progenitor cells are multipotent stem cells isolated from both embryonic and adult hearts in several species and are able to differentiate at least into smooth muscle cells, endothelial cells and cardiomyocytes. The embryonic origin of these cells has not yet been demonstrated, but it has been suggested that these cells may derive from the first and secondary heart fields and from the neural crest. In the last decade, two diffe-rent populations of cardiac progenitor or stem cells have been identified and isolated, i.e., the Islet1 positive (Isl1+) and c-Kit positive (c-Kit+)/Stem Cell Antigen-1 positive (Sca-1+) cells. Until 2012, these two populations have been considered two separate entities with different roles and a different origin, but new evidence now suggests a con-nection between the two populations and that the two populations may represent two subpopulations of a unique pool of cardiac stem cells, derived from a common immature primitive cell. To find a common consensus on this concept is very important in furthe-ring the application of stem cells to cardiac tissue engineering

Giovanni Filippo Ingrassia: A five-hundred year-long lesson.

Giovanni Filippo Ingrassia was born five centuries ago in Regalbuto, a small town in the center of Sicily. After his medical course in Padua, under the guidance of Vesalius and Fallopius, he gained international fame as a physician and was recruited as a Professor of human anatomy in Naples and later in Palermo. He is remembered as "the new Galen" or "the Sicilian Hippocrates." He contributed to the knowledge of human anatomy through the description of single bones rather than the whole skeleton. In particular, he was the first to describe the "stapes," the "lesser wings of the sphenoid" and various other structures in the head (probably the pharyngotympanic tube) as well as in the reproductive system (corpora cavernosa and seminal vesicles). He was also a pioneer in the study of forensic medicine, hygiene, surgical pathology, and teratology. As Protomedicus of Sicily, he developed the scientific culture in this country. During those years, he faced the spread of malaria and plague with competence and authoritativeness. Indeed, he was one of the first physicians to suppose that certain diseases could be transmitted between individuals, therefore, introducing revolutionary measures of prevention. He is remembered for his intellectual authority and honesty. Five-hundred years after his birth, his teaching is still alive. In this article, we survey the life and contribution of this pioneer of early anatomical study

MicroRNA and Cardiac Stem Cell Therapy

Cardiac Progenitor Cells (CPCs) are multipotent cells of the myocardium. They are located inside niches of the heart muscle, can be isolated, characterized and used for cardiac regeneration in stem cell therapy. Actually, CPCs may be isolated by tissue digestion with or without cell sorting, but it is difficult to achieve the maximum level of differentiation when these cells are implanted into a damaged myocardium. The knowledge recently acquired on small molecules of non-coding RNAs, microRNA (miRNA), may improve the use of these cells in stem cell therapy. In fact, these small molecules may be attached to devices or adminstered as they are or in combination with nanoparticles in order to drive the correct differentiation of stem cells. Regarding heart regeneration, we can acquire knowledge from the role of miRNAs in heart development and use it to reprogram CPCs to gain the correct three-dimensional structure of the cardiac muscle

Structural analysis of rat patellar tendon in response resistance and endurance training.

Little is known about tendon adaptations induced by mechanical loading. Our goal was to evaluate the effects of two different exercise training protocols on adult rat patellar tendon. Ninety-six male Wistar rats were divided into a sedentary group (control), a resistance-trained group and an endurance-trained group. The examinations were performed after 15, 30 and 45 days of training and after 2 weeks of rest since training was stopped. The content of collagen fibers and the cell nuclei number were quantified on tendon cross sections. In order to assess the training effectiveness, we evaluated the heart/body weight ratio, which was higher in 45 day-trained rats than their controls (P<0.01), showing the presence of cardiac hypertrophy. An increase in the content of collagen fibers was observed in the 45 day-trained groups and after 2 weeks of rest in the endurance group. Moreover, both trained groups showed a decrease in cell nuclei number after 30 and 45 days of training and 2 weeks of rest (P<0.05). Endurance and resistance training induces a tendon tissue remodeling that depends on the length and intensity of workload rather than the training type. Further studies are necessary to evaluate whether these structural modifications are associated with an increase in the mechanical strength of tendon

Involvement of caspase-3 and GD3 ganglioside in ceramide-induced apoptosis in Farber disease

Farber's disease (FD) is a rare genetic disorder caused by ceramidase deficiency, which results in ceramide accumulation in lung, liver, colon, skeletal muscle, cartilage, and bone. Although this disease has been symptomatically characterized, little is known about its molecular pathogenetic process. Because recent studies reported that ceramide accumulation induces GD3 ganglioside formation and apoptosis, we investigated, in tissue obtained via colonoscopy from seriously involved patients, the possible involvement of ceramide in FD colonocyte destruction. Histochemical and TUNEL analyses of paraffin-embedded sections revealed that 45 ± 4.3% of FD colonocytes showed morphological signs of apoptosis compared with the 8 ± 2.3% of constitutive epithelial cell death. Importantly, immunohistochemical study for pro-apoptotic factors showed that GD3 accumulation colocalized with active caspase-3 and cleaved K18 in FD colon tissue. These findings provide evidence for a role of the apoptotic ceramide pathway in the pathogenesis of FD