Dental mesenchymal stromal/stem cells in different microenvironments— implications in regenerative therapy

Current research data reveal microenvironment as a significant modifier of physical functions,pathologic changes,as well as the therapeutic effects of stem cells.When comparing regeneration potential of various stem cell types used for cytotherapy and tissue engineering,mesenchymal stem cells(MSCs)are currently the most attractive cell source for bone and tooth regeneration due to their differentiation and immunomodulatory potential and lack of ethical issues associated with their use.The microenvironment of donors and recipients selected in cytotherapy plays a crucial role in regenerative potential of transplanted MSCs,indicating interactions of cells with their microenvironment indispensable in MSC-mediated bone and dental regeneration.Since a variety of MSC populations have been procured from different parts of the tooth and tooth-supporting tissues,MSCs of dental origin and their achievements in capacity to reconstitute various dental tissues have gained attention of many research groups over the years.This review discusses recent advances in comparative analyses of dental MSC regeneration potential with regards to their tissue origin and specific microenvironmental conditions,giving additional insight into the current clinical application of these cells.

IMMUNOHISTOCHEMICAL DEMONSTRATION OF CCAAT/ENHANCER BINDING PROTEIN (C/EBP) IN HUMAN LIVER TISSUES OF VARIOUS ORIGIN

C / EBP is a sequence-specific DNA-binding protein. In order to indentify its distribution and localization, immunohistochemical technique (ABC method) was done using anti-C / EBP polypeptide antibodies 1103#, 425# in liver specimens from 20 normal adults, 5 neonates, 6 patients with hepatitis, 25 with liver cirrhosis, 80 with hepatocellular carcinoma (40 cases were associated with surrounding nontumorous tissues) and 26 patients with cholangiocarcinoma (15 cases were associated with surrounding nontumorous tissues). The results showed that C / EBP was diffusely distributed in nuclei and cytoplasm of differentiated liver cells and very low or undetectable in liver cancer cells. The manifestation of C / EBP correlated with degree of differentiation of tumour cells, and was obviously weaker than that in surrounding nontumorous tussues. C / EBP positive staining has also been found in regenerating epithelial cells of bile ductules. The results suggested that C / EBP should play an important role in establishing and maintaining the differentiation of liver cells.

Identification and characterization of two morphologically distinct stem cell subpopulations from human urine samples

Urine-derived stem cells(USCs)have shown potentials for the treatment of skeletal and urological disorders.Based on published literature and our own data,USCs consist of heterogeneous populations of cells.In this paper,we identify and characterize two morphologically distinct subpopulations of USCs from human urine samples,named as spindle-shaped USCs(SS-USCs)and rice-shaped USCs(RS-USCs)respectively.The two subpopulations showed similar clone-forming efficiency,while SS-USCs featured faster proliferation,higher motility,and greater potential for osteogenic and adipogenic differentiation,RS-USCs showed greater potential for chondrogenic differentiation.POU5F1 was strongly expressed in both subpopulations,but MYC was weakly expressed.Both subpopulations showed similar patterns of CD24,CD29,CD34,CD44,CD73,CD90 and CD105 expression,while a higher percentage of RS-USCs were positive for CD133.SS-USCs were positive for VIM,weakly positive for SLC12A1 and UMOD,and negative for KRT18,NPHS1,AQP1 and AQP2,indicating a renal mesenchyme origin;while RSUSCs are positive for VIM,partially positive for KRT18,NPHS1,AQP1,SLC12A1 and UMOD,and negative for AQP2,indicating a nephron tubule origin.The above results can facilitate understanding of the biological characteristics of subpopulations of USCs,and provide a basis for further research and applications of such cells.