The use of human sweat gland-derived stem cells for enhancing vascularization during dermal regeneration.

Vascularization is a key process in tissue engineering and regeneration and represents one of the most important issues in the field of regenerative medicine. Thus, several strategies to improve vascularization are currently under clinical evaluation. In this study, stem cells derived from human sweat glands were isolated, characterized, seeded in collagen scaffolds, and engrafted in a mouse full skin defect model for dermal regeneration.

A novel xenogeneic co-culture system to examine neuronal differentiation capability of various adult human stem cells.

Background: Targeted differentiation of stem cells is mainly achieved by the sequential administration of defined growth factors and cytokines, although these approaches are quite artificial, cost-intensive and time-consuming. We now present a simple xenogeneic rat brain co-culture system which supports neuronal differentiation of adult human stem cells under more in vivo-like conditions.

Methods And Findings: This system was applied to well-characterized stem cell populations isolated from human skin, parotid gland and pancreas.

The role of alpha-smooth muscle actin in myogenic differentiation of human glandular stem cells and their potential for smooth muscle cell replacement therapies.

Importance Of The Field: Cellular replacement therapies in vascular and urogenital organ disorders require an abundant source of smooth muscle cells. A promising approach would be the directed myogenic differentiation (characterized by the expression of alpha-smooth muscle actin (alpha-SMA)) into a sufficient amount of smooth muscle cells through easily obtainable adult stem cells, for example from the sweat gland.

Areas Covered In This Review: We present novel multipotent adult stem cell populations derived from glandular tissues like pancreas, salivary gland and sweat gland and assess their myogenic potential.

Phenotypic indications that human sweat glands are a rich source of nestin-positive stem cell populations.

Background: We have recently shown that the expression of nestin, a progenitor/stem cell marker protein, is localized in different mesenchymal compartments in human skin including the sweat gland stroma.

Objectives: As other exocrine glands are recognized sources of multipotent stem cell populations with potential for multilineage differentiation, it was our aim to isolate, expand and characterize glandular stem cells from human sweat glands.

Methods: Isolation of human sweat glands was based on mechanical and enzymatic digestion of axillary skin.

In vitro cultures of human pancreatic stem cells: gene and protein expression of designated markers varies with passage.

Adult stem cells may possess great plasticity, but the cellular mechanisms regulating their fate are not fully understood. Prior to application of stem cell populations in regenerative medicine, major challenges remain to be overcome. Fundamental questions about in vitro growth and spontaneous differentiation of adult stem cell populations must be resolved.

Controlling alpha-SMA expression in adult human pancreatic stem cells by soluble factors.

In the application of adult stem cells in regenerative medicine, it is indispensable to control stem cell behaviour in vitro. Since stem cells spontaneously differentiate into several cell types, it is mandatory to identify methods to enrich the desired cell types and concurrently block other differentiation pathways. More precisely, generation of a defined cell population is a key prerequisite for a therapeutic application of stem cells.

Adult pancreatic stem/progenitor cells spontaneously differentiate in vitro into multiple cell lineages and form teratoma-like structures.

Cells isolated from pancreas have a remarkable potential for self-renewal and multilineage differentiation. We here present a comprehensive characterisation of stem/progenitor cells derived from exocrine parts of the adult rat pancreas. Using purified cells from either single colonies or even single-cell clones, we specifically demonstrate: (i) the cells contain the typical stem/progenitor cell markers alkaline phophatase, SSEA-1, Oct-4, CD9, Nestin, Pax6, CD44, a-Fetoprotein and Brachyury, demonstrated by immunocytochemistry and RT-PCR; (ii) the cells have the potential to differentiate into lineages of all three germ layers in vitro; (iii) a clonal analysis revealed that even cell lines derived from a single cell have stem/progenitor cell properties such as self-renewal and spontaneous differentiation into various cell lineages; (iv) the cells have the propensity to form three-dimensional, teratoma-like structures in vitro, which contain cells of different lineages; and (v) external stimuli can activate the generation of certain cell types.

Towards the development of a pragmatic technique for isolating and differentiating nestin-positive cells from human scalp skin into neuronal and glial cell populations: generating neurons from human skin?

Nestin+ hair follicle-associated cells of murine skin can be isolated and differentiated in vitro into neuronal and glial cells. Therefore, we have asked whether human skin also contains nestin+ cells, and whether these can be differentiated in vitro into neuronal and/or glial cell populations. In this methodological pilot study, we show that both are indeed the case - employing purposely only very simple techniques for isolating, propagating, and differentiating nestin+ cells from normal human scalp skin and its appendages that do not require selective microdissection and tissue compartment isolation prior to cell culture.