Histology and histopathology Vol.25, nº6 (2010)
Ir a Estadísticas
Permanent URI for this collection
Browse
Recent Submissions
- PublicationOpen AccessDefining adipose tissue-derived stem cells in tissue and in culture(Murcia: F. Hernández, 2010) Lin, Ching-Shwun; Xin, Zhong-Cheng; Deng, Chun-Hua; Ning, Hongxiu; Lin, Guiting; Lue, Tom F.Adipose tissue-derived stem cells (ADSC) are routinely isolated from the stromal vascular fraction (SVF) of homogenized adipose tissue. Similar to other types of mesenchymal stem cells (MSC), ADSC remain difficult to define due to the lack of definitive cellular markers. Still, many types of MSC, including ADSC, have been shown to reside in a perivascular location, and increasing evidence shows that both MSC and ADSC may in fact be vascular stem cells (VSC). Locally, these cells differentiate into smooth muscle and endothelial cells that are assembled into newly formed blood vessels during angiogenesis and neovasculogenesis. Additionally, MSC or ADSC can also differentiate into tissue cells such as adipocytes in the adipose tissue. Systematically, MSC or ADSC are recruited to injury sites where they participate in the repair/regeneration of the injured tissue. Due to the vasculature’s dynamic capacity for growth and multipotential nature for diversification, VSC in tissue are individually at various stages and on different paths of differentiation. Therefore, when isolated and put in culture, these cells are expected to be heterogeneous in marker expression, renewal capacity, and differentiation potential. Although this heterogeneity of VSC does impose difficulties and cause confusions in basic science studies, its impact on the development of VSC as a therapeutic cell source has not been as apparent, as many preclinical and clinical trials have reported favorable outcomes. With this understanding, ADSC are generally defined as CD34+CD31- although loss of CD34 expression in culture is well documented. In adipose tissue, CD34 is localized to the intima and adventitia of blood vessels but not the media where cells expressing alpha-smooth muscle actin (SMA) exist. By excluding the intima, which contains the CD34+CD31+ endothelial cells, and the media, which contains the CD34-CD31- smooth muscle cells, it leaves the adventitia as the only possible location for the CD34+ ADSC. In the capillary, CD34 and CD140b (a pericyte marker) are mutually exclusively expressed, thus suggesting that pericytes are not the CD34+ ADSC. Many other cellular markers for vascular cells, stem cells, and stem cell niche have also been investigated as possible ADSC markers. Particularly the best-known MSC marker STRO-1 has been found either expressed or not expressed in cultured ADSC. In the adipose tissue, STRO-1 appears to be expressed exclusively in the endothelium of certain but not all blood vessels, and thus not associated with the CD34+ ADSC. In conclusion, we believe that ADSC exist as CD34+CD31-CD104b-SMA- cells in the capillary and in the adventitia of larger vessels. In the capillary these cells coexist with pericytes and endothelial cells, both of which are possibly progenies of ADSC (or more precisely VSC). In the larger vessels, these ADSC or VSC exist as specialized fibroblasts (having stem cell properties) in the adventitia.
- PublicationOpen AccessRole of neutrophil-derived matrix metalloproteinase-9 in tissue regeneration(Murcia: F. Hernández, 2010) Heissig, Beate; Nishida, Chiemi; Tashiro, Yoshihiko; Sato, Yayoi; Ishihara, Makoto; Ohki, Makiko; Gritli, Ismael; Rosenkvist, Jeanette; Hattori, KoichiIschemic tissue regeneration depends on neovascularization, the growth of new blood vessels. Bone marrow (BM)-derived cells, including neutrophils, have been shown to contribute to neovascularization during hind limb ischemia and inflammation. Neutrophils produce a broad array of angiogenic growth factors and proteases, which promote remodeling of arterioles into arteries through proteolytic mechanisms. Matrix metalloproteinases (MMPs) have been shown to play a role in the recruitment of neutrophils to sites of inflammation, which requires the extravascular migration of neutrophils through the extracellular matrix. Neutrophils control critical steps during angiogenesis and neutrophil-derived MMPs can promote neoangiogenesis, and collateral growth and perfusion recovery, in part by liberating vital angiogenic growth factors, including vascular endothelial growth factor-A (VEGF-A). This review focuses on the role of neutrophils as key players in the control of the angiogenic process during ischemic tissue regeneration. Aspects of neutrophil regulation, in particular regulation by its major growth factor granulocyte colonystimulating factor (G-CSF), the role of the unique, readily available, neutrophil-derived MMP-9, and the functional consequences of this MMP-9 activation for angiogenesis, such as MMP-mediated release of biologically relevant cytokines from the matrix and cell surfaces, will be discussed.
- PublicationOpen AccessMicroanatomy of lymphocyte-endothelial interactions at the high endothelial venules of lymph nodes(Murcia: F. Hernández, 2010) Tohya, Kazuo; Umemoto, Eiji; Miyasaka, MasayukiLymphocyte trafficking into lymph nodes and Peyer’s patches is mediated primarily by specifically differentiated venules, called high endothelial venules (HEVs), located in the tissue parenchyma. HEVs have a unique morphology and phenotype, which enables them to interact with circulating lymphocytes efficiently. That is, the HEV endothelial cells have a tall and plump appearance, and constitutively express multiple adhesion molecules and chemokines on their surface. These molecules can interact with cognate receptors on circulating lymphocytes, thereby mediating the stepwise and sequential lymphocyte adhesion and transendothelial migration (TEM) at the HEV endothelial luminal surface. This review summarizes the fine morphological aspects of the unique HEV endothelial cells, with special reference to the spatial distribution of the adhesion molecules and chemokines that regulate lymphocyte migration.
- PublicationOpen AccessDynorphin expression, processing and receptors in the alveolar macrophages, cancer cells and bronchial epithelium of lung cancer patients(Murcia: F. Hernández, 2010) Mousa, Shaaban A.; Krajnik, Malgorzata; Sobanski, Piotr; Kowalewski, Janusz; Bloch-Boguslawska, Elzbieta; Zylicz, Zbigniew; Schafer, MichaelFunctional evidence suggests that opioid peptides such as dynorphin are involved in the regulation of airway macrophage functions and of human cancer growth. However, anatomical evidence for components of a putative dynorphin network within lung cancer patients is scarce. Tissue from lung cancer patients was examined immunohistochemically for all components of a local dynorphin (DYN) network. Double immunofluorescence microscopy analysis revealed colocalization of the opioid precursor PDYN with its end-product DYN, and key processing enzymes prohormone convertases 1 and 2 and carboxypeptidase E, as well as the kappa-opioid receptor (KOR) within alveolar macrophages and cancerous cells in varying degrees among patients. Moreover, chromograninAimmunoreactive pulmonary neuroendocrine cells expressing DYN were close to substance P- and KORimmunoreactive sensory nerves. Our findings give a first hint of a neuroanatomical basis for a peripheral DYN network, conceivably regulating pulmonary, immune and cell-proliferative functions within the human lung, most likely in a paracrine/autocrine fashion.
- PublicationOpen AccessOxidized regenerated cellulose does not prevent the formation of experimental postoperative perineural fibrosis assessed by digital analysis(Murcia: F. Hernández, 2010) Hernández Cortés, Pedro; Peregrina, Magdalena; Aneiros Fernández, José; Tassi, Mohamed; Pajares López, Miguel; Toledo, Miguel; O’Valle, FranciscoIntroduction: It is difficult to prevent and treat intra- and peri-neural fibrosis after peripheral nerve surgery. Many authors have attempted to develop and verify the effectiveness of substances to decrease the formation of adherences in different tissues. Material and Methods: this study aimed to assess the effectiveness of a barrier of oxidized regenerated cellulose (ORC) to reduce adherence and perineural fibrosis in a model of surgical perineural induced fibrosis in rat sciatic nerve in 40 rats. After tissue aggression, the nerve of the right rear limb was wrapped in ORC and the left limb served as control. Animals were killed at 3 and 6 weeks, and nerves and muscle mass were extracted en bloc. Connective tissue was quantified by conventional histopathological techniques and Fibrosis HR® automatic image analysis. Results: No significant differences were found in intra- or peri-neural induced fibrosis between control nerves (6.88% and 8.90%, respectively) and treated nerves (6.57% and 9.90%) at 3 or 6 weeks (10.41% and 12.51% in controls; 11.85% and 15.72% in treated nerves). Inflammatory phenomena and granulomatous reactions were more frequent in treated animals. Conclusions: ORC conferred no advantage in prevention of nerve fibrosis and might have interfered with healing.
- «
- 1 (current)
- 2
- 3
- »