Fluorescent Nanodiamonds Enable Long-Term Detection of Human Adipose-Derived Stem/Stromal Cells in an In Vivo Chondrogenesis Model Using Decellularized Extracellular Matrices and Fibrin Glue Polymer.

Yur-Ren Kuo,Wei-Ting Wang,Mei-Ling Ho,John Yu,Hui-Min David Wang,Yi-Chia Wu,Long-Jyun Su,Hsin-Hung Lin,Chung-Sheng Lai,Ya-Chin Wang

doi:10.3390/polym11091391

Abstract

Clinically available materials, including allogeneic irradiated costal cartilage and fibrin glue polymer, were used as scaffolds for in vivo chondrogenic differentiation of human adipose-derived stem/stromal cells (hASCs) in the attempt to develop a more efficient treatment over current methods. Current studies include the use of growth-factor stimulation, tissue engineering, and biocompatible materials; however, most methods involve complicated processes and pose clinical limitations. In this report, the xenografts in the experimental group composed of a diced decellularized cartilage extracellular matrix (ECM), hASCs, and fibrin glue polymer were implanted into the subcutaneous layer of nude mice, and the results were compared with two groups of controls; one control group received implantation of decellularized cartilage ECM and fibrin glue polymer, and the other control group received implantation of hASCs mixed with fibrin glue polymer. To evaluate whether hASCs had in vivo chondrogenesis in the xenografts, hASCs were labeled with fluorescent nanodiamonds (FNDs), a biocompatible and photostable nanomaterial, to allow for long-term detection and histological analysis. Increased cellularity, glycosaminoglycan, and collagen deposition were found by the histological examination in the experimental group compared with control groups. With the background-free detection technique and time-gated fluorescence imaging, the numbers and locations of the FND-labeled hASCs could be detected by confocal microscopy. The chondrocyte-specific markers, such as aggrecan and type II collagen, were colocalized with cells containing signals of FNDs which indicated in vivo chondrogenesis of hASCs. Taken together, functional in vivo chondrogenesis of the hASCs could be achieved by clinically available decellularized cartilage ECM and fibrin glue polymer in the nude mice model without in vitro chondrogenic induction. The fluorescent signals of FNDs in hASCs can be detected in histological analysis, such as hematoxylin and eosin staining (H&E staining) without the interference of the autofluorescence. Our study may warrant future clinical applications of the combination of decellular cartilage ECM, fibrin glue polymer, and hASCs for cartilage repair.

Highlights

Articular cartilage is a highly specialized tissue acting as an absorber of weight during sustained static loading that cushions the ends of bones where they come together to form joints [1]
Fluorescent nanodiamonds (FNDs) in distilled deionized water for 15 min. They were mixed with the protein at a weight ratio of FND:human serum albumin (HSA) ≈ 1:1 by gentle shaking at room temperature for 2 h to allow physical adsorption
FNDs have been illustrated as cell-tracking materials [32,38,39], we examined whether the FNDs cytotoxicity in Human Adipose-Derived Stem/Stromal Cells (hASCs)

Summary

Introduction

Articular cartilage is a highly specialized tissue acting as an absorber of weight during sustained static loading that cushions the ends of bones where they come together to form joints [1]. Surgical interventions, aiming to either replace damaged chondral tissue or to induce repair, include arthroscopic debridement [4], bone marrow stimulation techniques [5,6], chondrocyte implantation [7,8], osteochondral autografts [9], osteoarthritis allograft [10], and total joint replacement for end-stage degenerative joint pathology [11]. Many of these approaches, often result in the formation of fibrocartilage that is biochemically and biomechanically inferior to hyaline articular cartilage. The repair of cartilaginous lesions is still a weighty clinical problem

Methods

Results

Conclusion