In vitro and in vivo cardiomyogenic differentiation of amniotic fluid stem cells.

Cell therapy has developed as a complementary treatment for myocardial regeneration. While both autologous and allogeneic uses have been advocated, the ideal candidate has not been identified yet. Amniotic fluid-derived stem (AFS) cells are potentially a promising resource for cell therapy and tissue engineering of myocardial injuries.

The cardiovascular unit as a dynamic player in disease and regeneration.

Cell-mediated cardiac regeneration remains a challenge as a therapeutic option in heart failure, but modest success using experimental models suggests that a better understanding of normal histogenesis will be needed to make progress towards cardiac regeneration. Recent studies of the heart show that the interstitium informs organogenesis and responsiveness to pathological stimuli through continuous bidirectional cross-talk between cardiomyocytes and non-cardiac cells. Here, we introduce the concept of the "cardiovascular unit" (CVU) as a building block of the heart, which includes cardiomyocytes and adjacent capillaries and fibroblasts.

The influence of heart valve leaflet matrix characteristics on the interaction between human mesenchymal stem cells and decellularized scaffolds.

The potential for in vitro colonization of decellularized valves by human bone marrow mesenchymal stem cells (hBM-MSCs) towards the anisotropic layers ventricularis and fibrosa and in homo- vs. heterotypic cell-ECM interactions has never been investigated. hBM-MSCs were expanded and characterized by immunofluorescence and FACS analysis.

From fish to amphibians to mammals: in search of novel strategies to optimize cardiac regeneration.

Different vertebrate species have different cardiac regeneration rates: high in teleost fish, moderate in urodele amphibians, and almost negligible in mammals. Regeneration may occur through stem and progenitor cell differentiation or via dedifferentiation with residual cardiomyocytes reentering the cell cycle. In this review, we will examine the ability of zebrafish and newts to respond to cardiac damage with de novo cardiogenesis, whereas rodents and humans respond with a marked fibrogenic response and virtually no cardiomyocyte regeneration.

Clones of interstitial cells from bovine aortic valve exhibit different calcifying potential when exposed to endotoxin and phosphate.

Objective: Our purpose was to study in vitro whether phenotypically-distinct interstitial cell clones from bovine aortic valve (BVIC) possess different calcifying potential in response to endotoxin (lipopolysaccharide [LPS]) and phosphate (Pi).

Methods And Results: Among various clones of BVIC obtained by limited dilution technique we selected 4 clones displaying different growth patterns and immunophenotypes. Uncloned and cloned cells were treated with combinations of LPS (100 ng/mL) and Pi (2.

Different cardiovascular potential of adult- and fetal-type mesenchymal stem cells in a rat model of heart cryoinjury.

Efficacy of adult (bone marrow, BM) versus fetal (amniotic fluid, AF) mesenchymal stem cells (MSCs) to replenish damaged rat heart tissues with new cardiovascular cells has not yet been established. We investigated on the differentiation potential of these two rat MSC populations in vitro and in a model of acute necrotizing injury (ANI) induced by cryoinjury. Isolated BM-MSCs and AF-MSCs were characterized by flow cytometry and cytocentrifugation and their potential for osteogenic, adipogenic, and cardiovascular differentiation assayed in vitro using specific induction media.

Gender differences in endothelial progenitor cells and cardiovascular risk profile: the role of female estrogens.

Objective: Endothelial progenitor cells (EPCs) participate in vascular homeostasis and angiogenesis. The aim of the present study was to explore EPC number and function in relation to cardiovascular risk, gender, and reproductive state.

Methods And Results: As measured by flow-cytometry in 210 healthy subjects, CD34(+)KDR(+) EPCs were higher in fertile women than in men, but were not different between postmenopausal women and age-matched men.

Technical notes on endothelial progenitor cells: ways to escape from the knowledge plateau.

In the last 10 years an increasing interest has been devoted to the study of endothelial progenitor cells (EPCs), a subtype of immature cells involved in endothelial repair and neoangiogenesis. EPCs have been discovered as a novel integrated part of the cardiovascular system, which plays a comprehensive role in tissue homeostasis. Consistently, alterations and/or reduction of the circulating EPC pool have been associated with different manifestations of cardiovascular disorders and atherosclerosis.

Effects of exercise training on endothelial progenitor cells in patients with chronic heart failure.

Background: The enhancement of circulating endothelial progenitor cells (EPCs) obtained by exercise training can be beneficial to patients with cardiac disease. Changes in the levels and differentiation of CD34(pos)/KDR(pos) EPCs, as well as the plasma concentration of vascular endothelial growth factor (VEGF) and stromal cell-derived factor (SDF)-1 EPC-mobilizing cytokines, were evaluated in patients with chronic heart failure after 8 weeks of supervised aerobic training (SAT) and 8 weeks of subsequent discontinued SAT (DSAT).

Methods And Results: The levels of circulating EPC and EPC differentiation potential of 22 patients who underwent SAT were studied by fluorescence-activated cell sorter analysis and colony forming-unit assay, respectively.

Neovascularization induced by porous collagen scaffold implanted on intact and cryoinjured rat hearts.

The potential of collagen scaffolds for promoting angiogenesis/arteriogenesis was studied in vivo by implantation on healthy or cryoinjured left ventricles of rats up to 60 days post-injury. Blood vessels content and extra-vascular cell infiltration were evaluated within the collagen scaffold, the cryoinjured areas, and the "border zones" of the myocardium facing the cryoinjured zones. The collagen cardiac patches were almost completely absorbed in 60 days and became populated by new arterioles and capillaries in both intact and cryoinjured heart (arterioles in cryoinjured vs.

Endothelial progenitor cells in the natural history of atherosclerosis.

Atherosclerotic diseases are responsible for a significant part of morbidity and mortality in western countries. According to the classical views, atherosclerotic lesions develop as the result of an inflammatory process initiated by endothelial damage. The discovery that bone marrow-derived cells participate in endothelial repair and new vessel growth has changed the pathogenetic models of cardiovascular disease.

Age is a risk factor for maladaptive changes in rats exposed to increased pressure loading of the right ventricular myocardium.

Objective: To study the adaptive potential of the right ventricular myocardium after 30 days of mechanical-induced overload in rats from two different age groups.

Materials And Methods: We banded the pulmonary trunk, so as to increase the systolic work load of the right ventricle, in 19 adult Sprague-Dawley rats at the age of 10 weeks, and 16 weanlings when they were 3 weeks-old, using 10 adults and 10 weanlings as controls. We analysed the functional adaptation and structural changes of the right ventricular myocardium, blood vessels and interstitial tissue after 30 days of increased afterload.

Human amniotic fluid-derived stem cells are rejected after transplantation in the myocardium of normal, ischemic, immuno-suppressed or immuno-deficient rat.

Human amniotic fluid-derived stem (AFS) cells, similarly to embryonic stem cells, could possess privileged immunological characteristics suitable for a successful transplantation even in a discordant xenograft system. We investigated whether AFS cells could be fruitfully used in a rat model of myocardial infarction. c-kit immunomagnetic-sorted AFS cells were characterized by flow cytometric analysis and cytospins as well as reverse-transcription polymerase chain reaction, Western blotting and immunocytochemistry for cardiovascular differentiation markers.

Amniotic fluid and bone marrow derived mesenchymal stem cells can be converted to smooth muscle cells in the cryo-injured rat bladder and prevent compensatory hypertrophy of surviving smooth muscle cells.

Purpose: Wound healing of the cryo-injured bladder can bring about organ remodeling because of incomplete reconstitution of depleted smooth muscle cells. Stem cell transplantation could be beneficial to improve smooth muscle cell regeneration and/or modulate the remodeling process. The repair of bladder injury using adult-type stem cells would be useful for adult urological patients but unsuited for neonatal patients, in whom major benefits are likely to derive from fetal-type stem cells.

Differential availability/processing of decorin precursor in arterial and venous smooth muscle cells.

The existence of specific differentiation markers for arterial smooth muscle (SM) cells is still a matter of debate. A clone named MM1 was isolated from a library of monoclonal antibodies to adult porcine aorta, which in vivo binds to arterial but not venous SM cells, except for the pulmonary vein. MM1 immunoreactivity in Western blotting involved bands in the range of M(r) 33-226 kDa, in both arterial and venous SM tissues.

Number and function of endothelial progenitor cells as a marker of severity for diabetic vasculopathy.

Objective: Peripheral arterial disease (PAD) is a threatening complication of diabetes. As endothelial progenitor cells (EPCs) are involved in neovasculogenesis and maintenance of vascular homeostasis, their impairment may have a role in the pathogenesis of diabetic vasculopathy. This study aimed to establish whether number and function of EPCs correlate with PAD severity in type 2 diabetic patients.

Amniotic mesenchymal cells autotransplanted in a porcine model of cardiac ischemia do not differentiate to cardiogenic phenotypes.

Objective: Transplantation of stem cells in the acute ischemic myocardium (AMI) may play a role in the recovery of cardiac function. Here, we investigated the ability of amniotic fluid-derived mesenchymal cells (AFC) for phenotypic conversion to vascular cells and cardiomyocytes (CM) when autotransplanted in a porcine model of AMI.

Methods: Single AFC preparations were taken from 12 fetuses 3 days before normal delivery.

Prevalence of fetal-type smooth muscle cells in the media of microvessels from hypertensive patients.

Significant structural and functional changes in smooth muscle cells (SMCs) of microvessels (diameter 30 to 300 microm) occur in hypertension. However, in microvessels of hypertensive patients, the differentiation pattern of SMCs underlying such changes remains undefined. To analyze the differentiation pattern of SMCs (adult, postnatal, or fetal), 49 muscle biopsies (rectus abdominis) were analyzed: 16 from children (aged 11 months to 11 years), 15 from normotensive adults (aged 55 to 74 years), 18 from hypertensive adults (aged 55 to 74 years).

Role of platelet activation in catheter-induced vascular wall injury.

Purpose: To investigate the role of smooth muscle cell (SMC) response and platelet activation in peripheral venous catheterization using a model of catheter injury associated with thrombocytopenic treatment.

Methods: Silicon elastic catheters were inserted into New Zealand White rabbit external jugular veins from 24 hours to 60 days. Immunocytochemical procedures with antibodies to differentiation markers specific for SMCs, myofibroblasts, and endothelial cells were used to ascertain the phenotypic features of injured venous SMCs and the tissue sleeve formed around the catheter.

Human fibroblasts from normal and malignant breast tissue grown in vitro show a distinct senescence profile and telomerase activity.

The telomerase activity and the senescence profile of cultured breast fibroblasts from normal human interstitial and malignant stromal tissue were studied in comparison with their proliferation and differentiation pattern. Fibroblasts were grown either in the presence or absence of a conditioned medium (CM) obtained from cultures of the oestrogen receptor-positive breast cancer MCF-7 cell line. At different passages (from the 2nd up to the 48th), fibroblasts were examined for the telomerase activity by the Telomerase Repeats Amplification Protocol (TRAP) assay, for proliferation profile by Ki-67 antigen expression, and the myofibroblast or smooth muscle cell-like differentiation pattern by immunofluorescence with monoclonal antibodies specific for smooth muscle markers.

Cell characterization of porcine aortic valve and decellularized leaflets repopulated with aortic valve interstitial cells: the VESALIO Project (Vitalitate Exornatum Succedaneum Aorticum Labore Ingenioso Obtenibitur).

Background: Heart valve bioprostheses for cardiac valve replacement are fabricated by xeno- or allograft tissues. Decellularization techniques and tissue engineering technologies applied to these tissues might contribute to the reduction in risk of calcification and immune response. Surprisingly, there are few data on the cell phenotypes obtained after cellularizing these naturally-derived biomaterials in comparison to those expressed in the intact valve.

Genetics, clinical and pathological features of glomerulonephritis associated with mutations of nonmuscle myosin IIA (Fechtner syndrome).

Background: Fechtner syndrome (FTNS), also known as Alport-like syndrome, is a rare inherited condition characterized by progressive nephritis, macrothrombocytopenia, Döhle-like leukocyte inclusions, deafness, and cataract. Although it recently was shown that FTNS derives from mutation of MYH9, the gene for the heavy chain of nonmuscle myosin IIA (NMMHC-IIA), its pathophysiological characteristics remain unknown.

Methods: We studied a large FTNS family in which 10 components carried a missense mutation of MYH9 determining the D1424H substitution.

Association between the --514 C-->T polymorphism of the hepatic lipase gene promoter and unstable carotid plaque in patients with severe carotid artery stenosis.

Objective: We investigated the potential association between -514 C-->T polymorphism in the promoter of the hepatic lipase gene (LIPC) and the prevalence of inflammatory cells in the plaque of patients with severe carotid artery stenosis.

Background: This common LIPC polymorphism has been related to the presence of an atherogenic lipoprotein pattern.

Methods: We studied 68 consecutive patients undergoing carotid endarterectomy.