title: Non-destructive studies of tissue-engineered phalanges by magnetic resonance microscopy and X-ray microtomography.
abstract: One of the intents of tissue engineering is to fabricate biological materials for the augmentation or replacement of impaired, damaged, or diseased human tissue. In this context, novel models of the human phalanges have been developed recently through suturing of polymer scaffolds supporting osteoblasts, chondrocytes, and tenocytes to mimic bone, cartilage, and tendon, respectively. Characterization of the model constructs has been accomplished previously through histological and biochemical means, both of which are necessarily destructive to the constructs. This report describes the application of two complementary, non-destructive, non-invasive techniques, magnetic resonance microscopy (MRM) and X-ray microtomography (XMT or quantitative computed tomography), to evaluate the spatial and temporal growth and developmental status of tissue elements within tissue-engineered constructs obtained after 10 and 38 weeks of implantation in athymic (nude) mice. These two times represent respective points at which model middle phalanges are comprised principally of organic components while being largely unmineralized and later become increasingly more mineralized. The spatial distribution of mineralized deposits within intact constructs was readily detected by XMT (qCT) and was comparable to low intensity zones observed on MRM hydration maps. Moreover, the MRM-derived hydration values for mineralized zones were inversely correlated with mineral densities measured by XMT. In addition, the MRM method successfully mapped fat deposits, collagenous tissues, and the hydration state of the soft tissue elements comprising the specimens. These results support the application of non-destructive, non-invasive, quantitative MRM and XMT for the evaluation of constituent tissue elements within complex constructs of engineered implants.
authors.affiliation: Magnetic Resonance Microscopy Facility, Armed Forces Institute of Pathology Annex, Rockville, MD 20850, USA.
authors.forename: Kimberlee
authors.initials: K
authors.lastname: Potter
authors.forename: Donald E
authors.initials: DE
authors.lastname: Sweet
authors.forename: Paul
authors.initials: P
authors.lastname: Anderson
authors.forename: Graham R
authors.initials: GR
authors.lastname: Davis
authors.forename: Noritaka
authors.initials: N
authors.lastname: Isogai
authors.forename: Shinichi
authors.initials: S
authors.lastname: Asamura
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Kusuhara
authors.forename: William J
authors.initials: WJ
authors.lastname: Landis
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D021522:Bioartificial Organs; D002358:Cartilage, Articular / Q000166:cytology; D002417:Cattle; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology; D003470:Culture Media; D050278:Finger Phalanges; D006801:Humans; D020007:Implants, Experimental; D019344:Lactic Acid / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D051379:Mice; D008819:Mice, Nude; D010006:Osteoblasts / Q000166:cytology; D011091:Polyesters; D011100:Polyglycolic Acid / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013997:Time Factors; D023822:Tissue Engineering; D014057:Tomography, X-Ray Computed
chemical_list: D003470:Culture Media; D011091:Polyesters; D011108:Polymers; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide)