Ideal xenograft or a perfect bone substitute?-A retrospective review and analysis of the historical concept of ivory implants in orthopaedics.

PURPOSE: Surgical treatment of fractures has evolved with the development of anaesthesia in 1846. Experiments with different implants both organic and non-organic had led to introduction of sometimes extremely peculiar materials coming from different species like ox bone or elephant's ivory. The aim of this article is to present not widely known concept of ivory use in bone surgery that set its foot in the history of orthopaedics and laid foundations for orthobiologic reconstructions. METHODS: Retrospective analysis of articles and books published between 1846 and 2017 that describe various examples of ivory application in the treatment of fresh fractures, non-unions and reconstruction of joints. RESULTS: Our research shows that ivory to the surgical world was introduced by Friedrich Dieffenbach, founder of the modern plastic surgery. It was also used with different rate of success by many of the famous surgeons of the nineteenth and twentieth century to include Trendelenburg, Billroth, Volkmann, Paget and Hey Groves. Ivory was immensely popular in bone surgery and became material of choice demonstrating amazing biological properties and very low rate of infections. CONCLUSION: Ivory has served well in successful treatment of various orthopaedic conditions for over 100 years. In this article, we are using history as a stepping stone to examine material that is not rejected by the body and promotes bony healing without increased infection or other complications. It is worth considering further analysis of historically acquired specimens for further development of materials for further orthopaedic fracture and reconstructive techniques.

Phenome of pearl quality traits in the mollusc transplant model Pinctada margaritifera.

The bivalve Pinctada margaritifera exhibits three main transplant phenotypes derived from the donor (from which a mantle graft tissue, the saibo, is excised), the recipient (into which the saibo is implanted with a nucleus, leading to the formation of a pearl sac "chimera") and the cultured pearls themselves. This first phenome study on the species derived from a large experimental graft. Transplant phenotype was assessed at three scales: 1) macro, pearl size, colour, grade, 2) micro, pearl surface microstructure, and 3) molecular, biomineralisation gene expression level in saibo and pearl sac tissues. From donor to pearl, the phenome revealed fine variations of quality traits dependent on the position on the mantle where the saibo was cut, whose variation could overlap with inter-individual donor phenotype differences. A single donor phenotype could therefore produce multiple pearl phenotypes at the scale of the saibo position, mirroring its original activity at the mantle position level and the colour and shape of the shell. This phenome study provides essential information on phenotypic trait architecture enabling us to explore and explain the main biological functions and pave the way for a phenomic project on P. margaritifera that could benefit the pearl industry.

Development and function of pearl-sacs grown from regenerated mantle graft tissue in the black-lip pearl oyster, Pinctada margaritifera (Linnaeus, 1758).

Current pearl grafting techniques were developed in the early 1900s and have changed little since. They involve the sacrifice of donor pearl oysters to provide graft tissue (saibo) that is implanted into host oysters. This study assessed the feasibility of using regenerated graft tissue for pearl production in the 'black-lip' pearl oyster, Pinctada margaritifera. Twelve days after grafting with regenerated graft tissue, there was complete encapsulation of the nucleus by the fully developed pearl-sac and the first layer of organic matrix had been secreted. Sixteen days after grafting, the pearl-sac was completely integrated with host tissue. The epithelial cells in the pearl-sac continued to secrete the organic matrix layer but there were no signs of nacre deposition at this stage. However, after three months of culture, nuclei in oysters grafted with regenerated mantle tissue were completely covered with nacre. The average nacre thickness on pearls produced from regenerated (0.547 ± 0.01 mm, n = 8) and normal (0.532 ± 0.01 mm, n = 8) mantle tissue did not differ significantly (p > 0.05). Nacre secretion rates, over the 80 day period subsequent to pearl-sac formation were 6.84 ± 0.1 µm day(-1) and 6.66 ± 0.1 µm day(-1) for oysters grafted with regenerated and normal mantle tissue, respectively. These means were not significantly different (p = 0.258). Our results clearly show that regenerated mantle tissue can function successfully as saibo for pearl production in P. margaritifera. This finding could provide significant benefits to pearl farmers and a basis for further development of current pearl grafting practices.

A xenograft mantle transplantation technique for producing a novel pearl in an akoya oyster host.

The brightness and color of pearls varies among different pearl-producing shellfish and have been a source of human fascination since ancient times. When produced through cultivation, the characteristics and quality of a pearl depend on the kind of shellfish used and also the transplanted mantle graft. This suggests that the Akoya pearl oyster, which is generally used in Japan for pearl culturing, can produce different kinds of pearl through the use of mantles from different species of shellfish. However, a transplanted heterogeneous mantle would be rejected by the immune system of the Akoya oyster. We have therefore developed a new method to suppress the Akoya immune system that archives immune tolerance to other shellfish. It is generally known that small quantities of antigens can be used to produce archived immunological tolerance in a clinical setting. We successfully suppressed the Akoya pearl oyster immune response against a Mabé pearl oyster graft through repeat injections of mantle homogenates. We then transplanted a Mabé pearl oyster mantle graft into the immunologically tolerant Akoya pearl oyster and obtained a Mabé pearl from an Akoya pearl oyster. Our new technique thus makes the production of novel and different pearls in the Akoya possible. We believe that this has significant future potential for the advancement of the pearl industry.

Expression of osteoblastic and osteoclastic genes during spontaneous regeneration and autotransplantation of goldfish scale: a new tool to study intramembranous bone regeneration.

Complementary DNA of osteoblast-specific genes (dlx5, runx2a, runx2b, osterix, RANKL, type I collagen, ALP, and osteocalcin) was cloned from goldfish (Carassius auratus) scale. Messenger RNA expressions were analyzed during spontaneous scale regeneration. Dlx5 had an early peak of expression on day 7, whereas osterix was constantly expressed during days 7-21. Runx2, a major osteoblastic transcription factor in mammalian bone, did not show any significant expression. The expressions of two functional genes, type I collagen and ALP, continually increased after day 7, while that of osteocalcin increased on day 14. As for osteoclastic markers, in addition to the cloning of two functional genes, TRAP and cathepsin K, in our previous study, we here cloned the transcription factor NFATc1 to use as an early osteoclastic marker. Using these bone markers, we investigate the signal key that controls the onset of scale resorption and regeneration by performing intra-scale-pocket autotransplantation of five groups of modified scales, namely, 1) methanol-fixed scale, 2) proteinase K-treated cell-free scale, 3) polarity reversal (upside-down) scale, 4) U-shape trimmed scale, and 5) circular-hole perforated scale. In this autotransplantation, each ontogenic scale was pulled out, modified, and then re-inserted into the same scale pocket. At post-transplant, inside the pockets of all modified transplant groups, new regenerating scales formed, attaching to the ongoing resorbed transplants. Autotransplantation of methanol-fixed scale, proteinase K-treated cell-free scale, and polarity reversal (upside-down) scale triggered scale resorption and scale regeneration. These two processes of scale resorption and regeneration occurred in accordance with osteoclastic and osteoblastic marker gene expressions. These results were microscopically confirmed using TRAP and ALP staining. Regarding the autotransplantation of U-shape trimmed and circular-hole perforated scales, new scales regenerated and grew at the trimmed/perforated part of each transplant, while scale resorption occurred apparently only around the trimmed/perforated area. In contrast, no scale resorption or regeneration was detected in sham transplantations. Our finding suggests that loss of correct cell-to-cell contact between the scale-pocket lining cells and the scale cortex cells is the key to switch on the onset of scale resorption and regeneration. Overall, the present study shows that goldfish scale regeneration shares similarities in gene expression with intramembranous bone regeneration. Improved understanding of goldfish scale regeneration will help elucidate the process of intramembranous bone regeneration and make goldfish scale a possible new tool to study bone regeneration.

Parathyroid hormone 1 (1-34) acts on the scales and involves calcium metabolism in goldfish.

The effect of fugu parathyroid hormone 1 (fugu PTH1) on osteoblasts and osteoclasts in teleosts was examined with an assay system using teleost scale and the following markers: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Synthetic fugu PTH1 (1-34) (100pg/ml-10ng/ml) significantly increased ALP activity at 6h of incubation. High-dose (10ng/ml) fugu PTH1 significantly increased ALP activity even after 18h of incubation. In the case of TRAP activity, fugu PTH1 did not change at 6h of incubation, but fugu PTH1 (100pg/ml-10ng/ml) significantly increased TRAP activity at 18h. Similar results were obtained for human PTH (1-34), but there was an even greater response with fugu PTH1 than with human PTH. In vitro, we demonstrated that both the receptor activator of the NF-κB ligand in osteoblasts and the receptor activator NF-κB mRNA expression in osteoclasts increased significantly by fugu PTH1 treatment. In an in vivo experiment, fugu PTH1 induced hypercalcemia resulted from the increase of both osteoblastic and osteoclastic activities in the scale as well as the decrease of scale calcium contents after fugu PTH1 injection. In addition, an in vitro experiment with intramuscular autotransplanted scale indicated that the ratio of multinucleated osteoclasts/mononucleated osteoclasts in PTH-treated scales was significantly higher than that in the control scales. Thus, we concluded that PTH acts on osteoblasts and osteoclasts in the scales and regulates calcium metabolism in goldfish.

A new fish scale-derived scaffold for corneal regeneration.

The purpose of this study is to develop a novel scaffold, derived from fish scales, as an alternative functional material with sufficient mechanical strength for corneal regenerative applications. Fish scales, which are usually considered as marine wastes, were acellularized, decalcified and fabricated into collagen scaffolds. The microstructure of the acellularized scaffold was imaged by scanning electron microscopy (SEM). The acellularization and decalcification treatments did not affect the naturally 3-dimentional, highly centrally-oriented micropatterned structure of the material. To assess the cytocompatibility of the scaffold with corneal cells, rabbit corneal cells were cultured on the scaffold and examined under SEM and confocal microscopy at different time periods. Rapid cell proliferation and migration on the scaffold were observed under SEM and confocal microscopy. The highly centrally-oriented micropatterned structure of the scaffold was beneficial for efficient nutrient and oxygen supply to the cells cultured in the three-dimensional matrices, and therefore it is useful for high-density cell seeding and spreading. Collectively, we demonstrate the superior cellular conductivity of the newly developed material. We provide evidences for the feasibility of the scaffold as a template for corneal cells growth and migration, and thus the fish scale-derived scaffold can be developed as a promising material for tissue-engineering of cornea.

The contribution of farm animals to human health.

Farm animals and their products have a longstanding and successful history of providing significant contributions to human nutrition, clothing, facilitation of labour, research, development and medicine and have thus been essential in improving life expectancy and human health. With the advent of transgenic technologies the potential of farm animals for improving human health is growing and many areas remain to be explored. Recent breakthroughs in reproductive technologies, such as somatic cloning and in vitro embryo production, and their merger with molecular genetic tools, will further advance progress in this field. Here, we have summarized the contribution of farm animals to human health, covering the production of antimicrobial peptides, dietary supplements or functional foods, animals used as disease models and the contribution of animals to solving urgent environmental problems and challenges in medicine such as the shortage of human cells, tissues and organs and therapeutic proteins. Some of these areas have already reached the level of preclinical testing or commercial application, others will be further advanced only when the genomes of the animals concerned have been sequenced and annotated. Provided the necessary precautions are being taken, the transmission of pathogens from animals to humans can be avoided to provide adequate security. Overall, the promising perspectives of farm animals and their products warrant further research and development in this field.

Ecdysteroids, juvenile hormone and vitellogenesis in the cockroach Leucophaea maderae.

Topical application of 400 micro g of the juvenile hormone analog, methoprene, to females of the penultimate instar of Leucophaea maderae failed to induce vitellogenin synthesis. However, last instar females showed an increasing response level in making vitellogenin as they aged during the first half of the instar. In the second half of the last instar the response to methoprene declined to nearly zero when the prothoracic glands have become highly active. Then, a few days before the metamorphic molt the responsiveness reached maximal levels, i.e., comparable to adult females. These data suggest that the fat body develops competency to produce vitellogenin during the last nymphal instar, but increasing titers of ecdysone then interfere with the action of methoprene and consequently production of vitellogenin is curtailed. When prothoracic glands from the second half of the last instar were implanted into adult females, the normal activation of the corpora allata, or their accelerated activation induced by mating, did not occur. Likewise, an activation of the corpora allata due to the severance of the NCCI was not observed when prothoracic glands had been implanted prior to such operations. Thus, ecdysone released by the prothoracic glands appeared to directly inhibit the isolated corpora allata in vivo i.e. without the mediation by the brain. Methoprene applied to allatectomized adult females induced vitellogenin synthesis in a dose dependent manner. This induction was, however, quantitatively reduced by implanted active prothoracic glands, particularly when low doses of methoprene had been applied. Methoprene higher than 5 micro g overcame the inhibitory potency of the implanted prothoracic glands. The effect of the prothoracic glands, i.e. ecdysone, appears to signal an interference with the action of methoprene at the target tissues, the fat body. The exposure of the fat body to a given juvenile hormone/ecdysone ratio dictates the apparent effectiveness of ecdysone. The precise mode of the interaction of juvenile hormone and ecdysone on the adult fat body is not known. These data show that ecdysone inhibits vitellogenesis by two independent mechanisms: 1) inhibition of the corpora allata resulting in the inhibition of juvenile hormone production and 2) inhibition of vitellogenin synthesis by the fat body. Both of these mechanisms appear to be operative in immature and mature animals. However, the action of ecdysones on the fat body is only seen after it had acquired competency to make vitellogenin during the last nymphal instar.

Interactions between the foot and bud patterning systems in Hydra vulgaris.

In the freshwater coelenterate, hydra, asexual reproduction via budding occurs at the base of the gastric region about two-thirds of the distance from the head to the foot. Developmental gradients of head and foot activation and inhibition originating from these organizing centers have long been assumed to control budding in hydra. Much has been learned over the years about these developmental gradients and axial pattern formation, and in particular, the inhibitory influence of the head on budding is well documented. However, understanding of the role of the foot and potential interactions between the foot, bud, and head patterning systems is lacking. The purpose of this study was to investigate the role of the foot in the initiation of new axis formation during budding by manipulating the foot and monitoring effects on the onset of first bud evagination and the time necessary to reach the 50% budding point. Several experimental situations were examined: the lower peduncle and foot (PF) were injured or removed, a second PF was laterally grafted onto animals either basally (below the budding zone) or apically (above the budding zone), or both the head and PF were removed simultaneously. When the PF was injured or removed, the onset of first bud evagination was delayed and/or the time until the 50% budding point was reached was longer. The effects were more pronounced when the manipulation was performed closer to the anticipated onset of budding. When PF tissue was doubled, precocious bud evagination was induced, regardless of graft location. Removal of the PF at the same time as decapitation reduced the inductive effect of decapitation on bud evagination. These results are discussed in light of potential signals from the foot or interactions between the foot and head patterning systems that might influence bud axis initiation.