Adipose-derived stromal cells for the reconstruction of a human vesical equivalent

Journal Reference

J Tissue Eng Regen Med. 2015;9(11):E135-43.

Rousseau A¹, Fradette J¹, Bernard G¹, Gauvin R¹, Laterreur V¹, Bolduc S^1,2

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1. Centre LOEX de l’Université Laval, Génie Tissulaire et Régénération, LOEX du Centre de Recherche FRSQ du CHU de Québec, Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
2. CMDGT/LOEX-ÉquipeReconstruction Vésicale, Centre de Recherche FRQS du CHU de Québec, Aile-R, Hôpital de l’Enfant-Jésus, Centre Hospitalier Affilié Universitaire de Québec, QC, Canada.

Abstract

Despite a wide panel of tissue-engineering models available for vesical reconstruction, the lack of a differentiated urothelium remains their main common limitation. For the first time to our knowledge, an entirely human vesical equivalent, free of exogenous matrix, has been reconstructed using the self-assembly method. Moreover, we tested the contribution of adipose-derived stromal cells, an easily available source of mesenchymal cells featuring many potential advantages, by reconstructing three types of equivalent, named fibroblast vesical  equivalent, adipose-derived stromal cell vesical equivalent and hybrid vesical equivalent – the latter containing both adipose-derived  stromal  cells and fibroblasts. The new substitutes have been compared and characterized for matrix composition and organization, functionality and mechanical behaviour. Although all three vesical equivalents displayed adequate collagen type I and III expression, only two of them, fibroblast vesical equivalent and hybrid vesical equivalent, sustained the development of a differentiated and functional urothelium. The presence of uroplakins Ib, II and III and the tight junction marker ZO-1 was detected and correlated with impermeability. The mechanical resistance of these tissues was sufficient for use by surgeons. We present here in vitro tissue-engineered vesical equivalents, built without the use of any exogenous matrix, able to sustain mechanical stress and to support the formation of a functional urothelium, i.e. able to display a barrier function similar to that of native tissue. Copyright © 2013 John Wiley & Sons, Ltd.

Copyright © 2013 John Wiley & Sons, Ltd.

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Regulation of GABA Equilibrium Potential by mGluRs in Rat Hippocampal CA1 Neurons

Journal Reference

PLoS One. 2015;10(9):e0138215.

Yang B¹, Rajput PS², Kumar U², Sastry BR¹.

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1. Neuroscience Research Laboratory, Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, Canada.
2. Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada.

Abstract

The equilibrium potential for GABA-A receptor mediated currents (EGABA) in neonatal central neurons is set at a relatively depolarized level, which is suggested to be caused by a low expression of K+/Cl- co-transporter (KCC2) but a relatively high expression of Na+-K+-Cl- cotransporter (NKCC1). Theta-burst stimulation (TBS) in stratum radiatum induces a negative shift in EGABA in juvenile hippocampal CA1 pyramidal neurons. In the current study, the effects of TBS on EGABA in neonatal and juvenile hippocampal CA1 neurons and the underlying mechanisms were examined. Metabotropic glutamate receptors (mGluRs) are suggested to modulate KCC2 and NKCC1 levels in cortical neurons. Therefore, the involvement of mGluRs in the regulation of KCC2 or NKCC1 activity, and thus EGABA, following TBS was also investigated. Whole-cell patch recordings were made from Wistar rat hippocampal CA1 pyramidal neurons, in a slice preparation. In neonates, TBS induces a positive shift in EGABA, which was prevented by NKCC1 antisense but not NKCC1 sense mRNA. (RS)-a-Methyl-4-carboxyphenylglycine (MCPG), a group I and II mGluR antagonist, blocked TBS-induced shifts in both juvenile and neonatal hippocampal neurons. While blockade of mGluR1 or mGluR5 alone could interfere with TBS-induced shifts in EGABA in neonates, only a combined blockade could do the same in juveniles. These results indicate that TBS induces a negative shift in EGABA in juvenile hippocampal neurons but a positive shift in neonatal hippocampal neurons via corresponding changes in KCC2 and NKCC1 expressions, respectively. mGluR activation seems to be necessary for both shifts to occur while the specific receptor subtype involved seems to vary.

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