Promoting and Harmful Effects of Steroid Hormones on Renal Stem/Progenitor Cell Development

2014

IJMS

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Stem/progenitor cells are promising candidates for the regeneration of parenchyma in acute and chronic renal failure. However, recent data exhibit that survival of stem/progenitor cells after implantation in diseased renal parenchyma is restricted. To elaborate basic parameters improving survival, cell seeding was simulated under advanced in vitro conditions. After isolation, renal stem/progenitor cells were mounted in a polyester interstitium for perfusion culture. During generation of tubules, chemically defined CO2 Independent Medium or Leibovitz’s L-15 Medium was applied. Specimens were then fixed for transmission electron microscopy to analyze morphological features in generated tubules. Fixation in conventional glutaraldehyde (GA) solution shows development of tubules each exhibiting a polarized epithelium, an intact basal lamina and an inconspicuous interstitium. In contrast, special fixation of specimens in GA solution containing cupromeronic blue, ruthenium red or tannic acid unveils previously not visible extracellular matrix. Control experiments elucidate that a comparable extracellular matrix is not present in the interstitium of the matured kidney. Thus, generation of renal tubules in combination with advanced fixation of specimens for electron microscopy demonstrates that development of abnormal features in the newly developed interstitium has to be considered, when repair of renal parenchyma is performed by implantation of stem/progenitor cells.

Section: Resultsmentioning

confidence: 99%

Detection of Abnormal Extracellular Matrix in the Interstitium of Regenerating Renal Tubules

2014

IJMS

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“…Recent data further illustrate that developing tubules avoid a direct contact to each other by keeping a discrete distance during spatial development. The separation seems to be caused by an interaction between the basal lamina of generating tubules, newly synthesized fibers of the extracellular matrix and neighboring polyester fibers of the fleece [116–122].…”

Section: Reviewmentioning

confidence: 99%

“…Finally, perfusion culture experiments exhibited that application of different kinds of polyester fleeces are leading to various patterns of spatial tubule development resulting in new challenging perspectives for the regeneration of diseased renal parenchyma [31]. By performing these pilot experiments it became evident that aldosterone has a stimulating influence on the formation of renal tubules, while glucocorticoids are inducing atypical structures in form of extended cell clusters [122]. In conclusion, it is an important new finding that steroid hormones occurring in the interstitial fluid may exhibit a harmful influence on the regeneration of renal parenchyma.…”

Section: Reviewmentioning

confidence: 99%

Supportive development of functional tissues for biomedical research using the MINUSHEET® perfusion system

Clinical & Translational Med

2012

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Functional tissues generated under in vitro conditions are urgently needed in biomedical research. However, the engineering of tissues is rather difficult, since their development is influenced by numerous parameters. In consequence, a versatile culture system was developed to respond the unmet needs. Optimal adhesion for cells in this system is reached by the selection of individual biomaterials. To protect cells during handling and culture, the biomaterial is mounted onto a MINUSHEET® tissue carrier. While adherence of cells takes place in the static environment of a 24 well culture plate, generation of tissues is accomplished in one of several available perfusion culture containers. In the basic version a continuous flow of always fresh culture medium is provided to the developing tissue. In a gradient perfusion culture container epithelia are exposed to different fluids at the luminal and basal sides. Another special container with a transparent lid and base enables microscopic visualization of ongoing tissue development. A further container exhibits a flexible silicone lid to apply force onto the developing tissue thereby mimicking mechanical load that is required for developing connective and muscular tissue. Finally, stem/progenitor cells are kept at the interface of an artificial polyester interstitium within a perfusion culture container offering for example an optimal environment for the spatial development of renal tubules. The system presented here was evaluated by various research groups. As a result a variety of publications including most interesting applications were published. In the present paper these data were reviewed and analyzed. All of the results point out that the cell biological profile of engineered tissues can be strongly improved, when the introduced perfusion culture technique is applied in combination with specific biomaterials supporting primary adhesion of cells.

“…A new finding was that formation of tubules can be induced by aldosterone, while antagonists such as spironolactone or canrenoate prevent development (Minuth et al 2007b(Minuth et al , 2010a. When the contact between the mineralocorticoid receptor (MR) and heat shock protein 90 is disturbed by geldanamycin, formation of intact tubules is reduced, while atypical features arise in form of cell clusters.…”

Section: Regeneration Of Renal Parenchymamentioning

confidence: 99%

Bridging the gap between traditional cell cultures and bioreactors applied in regenerative medicine: practical experiences with the MINUSHEET perfusion culture system

2015

Cytotechnology

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To meet specific requirements of developing tissues urgently needed in tissue engineering, biomaterial research and drug toxicity testing, a versatile perfusion culture system was developed. First an individual biomaterial is selected and then mounted in a MINUSHEET Ò tissue carrier. After sterilization the assembly is transferred by fine forceps to a 24 well culture plate for seeding cells or mounting tissue on it. To support spatial (3D) development a carrier can be placed in various types of perfusion culture containers. In the basic version a constant flow of culture medium provides contained tissue with always fresh nutrition and respiratory gas. For example, epithelia can be transferred to a gradient container, where they are exposed to different fluids at the luminal and basal side. To observe development of tissue under the microscope, in a different type of container a transparent lid and base are integrated. Finally, stem/progenitor cells are incubated in a container filled by an artificial interstitium to support spatial development. In the past years the described system was applied in numerous own and external investigations. To present an actual overview of resulting experimental data, the present paper was written.