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Biology Articles » Bioengineering » Soluble, insoluble and geometric signals sculpt the architecture of mineralized tissues » Figures

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- Soluble, insoluble and geometric signals sculpt the architecture of mineralized tissues

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Fig. 1 Tissue induction and morphogenesis by bone morphogenetic/osteogenic proteins (BMPs/OPs). (A) Islands of chondrogenesis with vascular invasion and osteoblastic differentiation and matrix synthesis as a recapitulation of embryonic development, 8 days after heterotopic implantation in a Long-Evans rat of 2.5µg of recombinant hOP-1 in conjunction with 25 mg of bovine insoluble collagenous bone matrix as carrier (original magnification x45). (B) Bone induction by naturally-derived BMPs/OPs purified from baboon bone matrix and implanted orthotopically in a calvarial defect of an adult baboon Papio ursinus: 30 days after implantation of 280µg of baboon osteogenic fractions after gel filtration chromatography there is induction of large osteoid seams in orange-red surfacing newly developed mineralized bone matrix in blue (undecalcified section, original magnification x25). (C) Low-power view of a corticalized ossicle induced after the implantation of 125µg of recombinant hTGF-β in the rectus abdominis muscle of an adult primate Papio ursinus showing vigorous osteogenesis with osteoid synthesis 30 days after heterotopic implantation (undecalcified section, original magnification x4.5).

Figure 1

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Fig. 2 Morphology of calvarial regeneration by recombinant hTGF-β2 in conjunction with collagenous matrix as carrier. Low-power photomicrographs of calvarial defects treated by 100µg hTGF-β2 delivered by insoluble collagenous bone matrix and harvested on day 30 (A) and 90 (B) after implantation in non-healing calvarial defects of the primate Papio ursinus. Minimal bone formation at the edges of the defect on day 30 (A) and osteogenesis albeit limited is found in a specimen harvested 90 days after implantation with bone formation only pericranially. Note the trabeculae of newly formed bone facing scattered remnants of collagenous matrix particles, embedded in a loose but highly vascular connective tissue matrix (undecalcified sections, original magnification x3).

Figure 2

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Fig. 3 Northern analyses of type IV collagen and Smad6 (A) and OP-1, BMP-3, TGF-β1 and type II and IV collagens mRNA expression (B) in tissues generated by rhTGF-β alone (A) and in ossicles generated by doses of porcine platelet-derived TGF-β1 alone and in combination with 25ìg hOP-1 implanted heterotopically with insoluble collagenous bone matrix as carrier in the rectus abdominis muscle of adult primates Papio ursinus and harvested on day 30. Minimal mRNA expression of Smad6 in ossicles generated by rhTGF-β when implanted heterotopically (A). (B) Upon implantation of 5 µg doses of recombinant hTGF-β1 there is expression of osteogenic markers of the TGF-β superfamily, namely OP-1 and BMP-3 gene products. Note the two to three fold increase of expression of collagen type IV mRNA, a marker of angiogenesis, in ossicles generated by TGF-β1 alone and in synergistic binary application with hOP-1 (B).

Figure 3a

Figure 3b

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Fig. 4 Effect of the geometry of the substratum of biomimetic matrices on tissue morphogenesis and bone induction on day 30. (A) Capillary sprouting, invasion and elongation of the capillaries within a concavity of a biomimetic matrix of highly crystalline hidroxyapatite implanted heterotopically in the rectus abdominis muscle of Papio ursinus and harvested 30 days after implantation. Top right note the newly formed bone in direct contact with the hydroxyapatite substratum (decalcified section, original magnification x45). (B) Spontaneous initiation of bone formation within a concavity of the biomimetic matrix without the addition of exogenously applied BMPs/OPs. The newly formed bone in light blue in direct contact with the hydroxyapatite substratum is surfaced by contiguous osteoblasts (decalcified section, original magnification x60). (C) Detail of another specimen showing the spontaneous initiation of bone formation in direct contact to the crystalline hydroxyapatite together with capillary invasion within the fibrovascular tissue invading the concavity (decalcified section, original magnification x60).

Figure 4

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Fig. 5 Tissue morphogenesis in concavities of the substratum 90 days after heterotopic implantation in the rectus abdominis muscle of the primate Papio ursinus. Low power view of a histological section of a monolithic disc of highly crystalline hydroxyapatite: bone has formed only within the concavities prepared on both planar outer surfaces (decalcified section, original magnification x12).

Figure 5

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Source: J. Cell. Mol. Med. Vol 8, No 2, 2004 pp. 169-180  


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