Engineered Immature Testicular Tissue by Electrospun Mats for Prepubertal Fertility Preservation in a Bioluminescence Imaging Transgenic Mouse Model.

Prepubertal boys with cancer may suffer from reduced fertility and maturity following gonadotoxic chemoradiotherapy. Thus, a viable method of immature testicular tissue (ITT) preservation is required in this cohort. In this study, we used poly-L-lactic acid electrospun scaffolds with two levels of fineness to support the development of ITT transplanted from transgenic donors to wild-type recipient mice. The purpose of this study was to evaluate the potential of ITT transplantation and spermatogenesis after using the two scaffolds, employing bioluminescence imaging for evaluation. The results suggest that ITT from 4-week-old mice possessed the most potential in spermatogenesis on the 70th day, together with the fine electrospun scaffolds. Moreover, bioluminescent imaging intensity was observed in recipient mice for up to 107 days, approximately six times more than the coarse electrospun scaffold and the control group. This occurs since the fine scaffold is more akin to the microenvironment of native testicular tissue as it reduces stiffness resulting from micronization and body fluid infiltration. The thermal analysis also exhibited recrystallization during the biodegradation process, which can lead to a more stable microenvironment. Overall, these findings present the prospect of fertility preservation in prepubertal males and could serve as a framework for future applications.

A Novel HA/ß-TCP-Collagen Composite Enhanced New Bone Formation for Dental Extraction Socket Preservation in Beagle Dogs.

Past studies in humans have demonstrated horizontal and vertical bone loss after six months following tooth extraction. Many biomaterials have been developed to preserve bone volume after tooth extraction. Type I collagen serves as an excellent delivery system for growth factors and promotes angiogenesis. Calcium phosphate ceramics have also been investigated because their mineral chemistry resembles human bone. The aim of this study was to compare the performance of a novel bioresorbable purified fibrillar collagen and hydroxyapatite/ß-tricalcium phosphate (HA/ß-TCP) ceramic composite versus collagen alone and a bovine xenograft-collagen composite in beagles. Collagen plugs, bovine graft-collagen composite and HA/ß-TCP-collagen composite were implanted into the left and right first, second and third mandibular premolars, and the fourth molar was left empty for natural healing. In total, 20 male beagle dogs were used, and quantitative and histological analyses of the extraction ridge was done. The smallest width reduction was 19.09% ± 8.81% with the HA/ß-TCP-collagen composite at Week 8, accompanied by new bone formation at Weeks 4 and 8. The HA/ß-TCP-collagen composite performed well, as a new osteoconductive and biomimetic composite biomaterial, for socket bone preservation after tooth extraction.

In vivo evaluation of resorbable bone graft substitutes in beagles: histological properties.

Calcium phosphate cement (CPC) is a promising material for use in minimally invasive surgery for bone defect repairs due to its bone-like apatitic final setting product, biocompatibility, bioactivity, self-setting characteristics, low setting temperature, adequate stiffness, and easy shaping into complicated geometrics. However, even though CPC is stable in vivo, the resorption rate of this bone cement is very slow and its long setting time poses difficulties for clinical use. Calcium sulfate dehydrate (CSD) has been used as a filler material and/or as a replacement for cancellous bone grafts due to its biocompatibility. However, it is resorbed too quickly to be optimal for bone regeneration. This study examines the invivo response of a hydroxyapatite (HA), [apatitic phase (AP)]/calcium sulfate (CSD) composite using different ratios in the mandibular premolar sockets of beagles. The HA (AP)/CSD composite materials were prepared in the ratios of 30/70, 50/50, and 70/30 and then implanted into the mandibular premolar sockets for terms of 5 and 10 weeks. The control socket was left empty. The study shows better new bone morphology and more new bone area in the histological and the histomorphometric study of the HA (AP)/CSD in the 50/50 ratio.

In vivo evaluation of resorbable bone graft substitutes in mandibular sockets of the beagle.

Hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2)), with its high biocompatibility and good bioaffinity, stimulates osteoconduction and is slowly replaced by the host bone after implantation. However, clinical use of HA as a bone substitute has proved problematic. It is difficult to prevent dispersion of the HA granules and to mold the granules into the desired shape. Calcium sulfate as a bone graft substitute is rapidly resorbed in vivo releasing calcium ions, but fails to provide a long-term, three-dimensional framework to support osteoconduction. The setting properties of calcium sulfate, however, allow it to be applied in a slurry form, making it easier to handle and apply in different situations. This study examines the in vivo response of a (Hydroxyapatite, apatitic phase)/calcium sulfate dehydrate (CSD) composite using different ratios in the mandibular premolar sockets of the beagle. The HA (AP)/CSD composite materials prepared in ratios of 30/70, 50/50, and 70/30 were implanted into the mandibular premolar sockets for 5 and 10 weeks. The control socket was empty. The authors compared the radiographic properties and the changes in height and width of the mandibular premolar sockets in the beagle. The composite graft in the 30/70 ratio had the best ability to form new bones.