In vivo regeneration functionalities of experimental organo-biomaterials containing water-soluble nacre extract

Abstract

BackgroundNovel multifunctional biomaterials were recently designed to allow for an optimized tissue regeneration process.PurposeTo comprehensively assess (photographic, radiographic and histological) the in vivo functionality of demineralized bovine bone matrix (DBM) associated with an experimental marine organic extract (MOE) from nacre in a sheep ectopic grafting model.Materials and methodsSynthesis of MOE was based on mixing powdered nacre (0.05 g, particles average size <0.1 mm) with acetic acid (5 mL, pH 7) under constant stirring for 72 hours (25 °C). Polyethylene tubes (3/animal, n = 4, diameter: 5.0 mm × length: 10.0 mm) from the control (empty) or experimental groups (DBM or DBM + MOE) were then intramuscularly implanted into the lumbar regions of sheep (n = 8, 2-years old, ≈45 kg). Animals were euthanized at 3 and 6 months to allow for the collection of tissue samples. Tissue samples were fixed in formalin 10% (buffered, 7 days) in preparation for photographic, radiographic and histological assessments. Acquired images were then analyzed using digital image analysis software to quantify the amount of neoformed tissues, whereas radiographic and histological analyses were performed to determine radiopacity and classification of tissues deposited inside of the tubes.ResultsPhotographic and radiographic analyses have shown that both pure (unaltered) and MOE-modified DBM were capable of depositing neoformed tissues (at 3 and 6 months), where higher levels of deposition and radiopacity were observed on groups treated with experimental materials. Histological results, however, demonstrated that tissues formed from both unaltered and MOE-modified DBM were only fibrous connective in origin.ConclusionsAs an ectopic grafting in sheep, the experimental organo-biomaterial association applied did not reveal any osteoinductive property but led to a fibrous tissue repair only.

The Role of Marine Organic Extract in Bone Regeneration: A Pilot Study

“…e reason for the selection of nonreactive polymer carriers was based on results reported previously by our group [19,25], where intramuscular implantation of tubes (identical composition and similar surgical conditions) did not generate any type of allergic or inflammatory reactions in sheep models. Figures 1(a)-1(h) illustrate the macroscopic, radiographic, and histological results for specimens pertaining to the control groups (1 and 4).…”

“…Our laboratory has previously reported the methodology used for the fabrication of the experimental MOE used in the present study [19]. A local seafood supplier provided frozen Perna perna (brown) mussels.…”

“…Procedures. Euthanization of animals was performed (at 3 or 6 months) using a previously published protocol [19]. Sodium thiopental IV (8 mg/Kg, iopentax, Brazil) and potassium chloride (20 mL, 19.1%, Brazil) were intramuscularly administered to allow the removal of specimens (each nonreactive carrier displayed roughly 1.0 cm of encircling tissues).…”

“…Extensive research efforts to overcome previously cited limitations resulted in the attainment of novel biocompatible organobiomaterials such as natural hydroxyapatite (HA) [15,16], β-tricalcium phosphate (TCP) [17], and low-temperature apatites (LTA) [18]. More recently, our laboratory has reported a pilot study describing the in vivo bone repair utility of demineralized bone matrix (DBM) modified by an experimental nacre extract (MOE) in a sheep ectopic model [19].…”

In vivo transdifferentiation, osteoconductive and osteoinductive properties of experimental water-soluble organo-biomaterials – A Pilot Study

“…A recent study investigating the in vivo regeneration functionalities of experimental organo-biomaterials containing watersoluble nacre extracts (Zielak et al, 2018) reported a simple method for the fabrication of experimental implantable biomaterials with favorable osteoinductive and osteogenic properties. According to Addadi et al (2006) and Huang and Li (2012) nacre has attracted wide spread interest in biomineralization studies because of its unique self-assembled hierarchical structure based on a naturally-occurring nanocomposite composed by polygonal aragonite platelets (thickness between 200-500 nm) and interlamellar layers of a water-soluble organic biopolymer.…”