Development of an alginate-chitosan biopolymer composite with dECM bioink additive for organ-on-a-chip articular cartilage.

In vitro use of articular cartilage on an organ-on-a-chip (OOAC) via microfluidics is challenging owing to the dense extracellular matrix (ECM) composed of numerous protein moieties and few chondrocytes, which has limited proliferation potential and microscale translation. Hence, this study proposes a novel approach for using a combination of biopolymers and decellularised ECM (dECM) as a bioink additive in the development of scalable OOAC using a microfluidic platform. The bioink was tested with native chondrocytes and mesenchymal stem cell-induced chondrocytes using biopolymers of alginate and chitosan composite hydrogels. Two-dimensional (2D) and three-dimensional (3D) biomimetic tissue construction approaches have been used to characterise the morphology and cellular marker expression (by histology and confocal laser scanning microscopy), viability (cell viability dye using flow cytometry), and genotypic expression of ECM-specific markers (by quantitative PCR). The results demonstrated that the bioink had a significant impact on the increase in phenotypic and genotypic expression, with a statistical significance level of p < 0.05 according to Student's t-test. The use of a cell-laden biopolymer as a bioink optimised the niche conditions for obtaining hyaline-type cartilage under culture conditions, paving the way for testing mechano-responsive properties and translating these findings to a cartilage-on-a-chip microfluidics system.

Extracellular matrix composition analysis of human articular cartilage for the development of organ-on-a-chip.

INTRODUCTION: Articular cartilage has a complex extracellular matrix (ECM) that provides it a defined architecture for its load-bearing properties. The complete understanding of ECM components is imperative for developing biomimetic organ-on-a-chip tissue construct. OBJECTIVE: This study aimed to decellularize and characterize the ECM for its protein profiling to generate a niche for enhanced chondrocyte proliferation. METHODS: Articular cartilage scrapings were subjected to mechanical and collagenase digestion, followed by sodium dodecyl sulfate (SDS) treatment for 8 h and 16 h. The de-cellularization efficiency was confirmed by hematoxylin & eosin, alcian blue, masson's trichrome staining, and scanning electron microscopy (SEM). The ECM protein profile was quantified by liquid chromatography tandem mass spectrometry (LC-MS/MS) using a bottom-up approach. RESULTS: Histological characterization revealed void lacunae that lacked staining for cellular components. The ECM, sulfated glycosaminoglycan content, and collagen fibers were preserved after 8 h and 16 h of de-cellularization. The SEM ultrastructure images showed that few chondrocytes adhered to the ECM after 8 h and cell-free ECM after 16 h of de-cellularization. LC-MS/MS analysis identified 66 proteins with heterotypic collagen types COL1A1-COL6A1, COL14A1, COL22A1 and COL25A1 showed moderate fold change and expression levels, while COL18A1, COL26A1, chondroitin sulfate, matrix metalloproteinase-9 (MMP9), fibronectin, platelet glycoprotein 1 beta alpha (GP1BA), vimentin, bone morphogenetic protein 6 (BMP6), fibroblast growth factor 4 (FGF4) and growth hormone receptor (GHR) showed maximum fold change and expression levels. CONCLUSIONS: The standardized de-cellularization process could preserve majority of ECM components, providing structural integrity and architecture to the ECM. The Identified proteins quantified for their expression levels provided insight into engineering the ECM composition for developing cartilage-on-a-chip.

Short-term comparative outcomes between reverse shoulder arthroplasty for shoulder trauma and shoulder arthritis: a Southeast Asian experience.

BACKGROUND: Reverse shoulder arthroplasty (RSA), first introduced as a management option for cuff tear arthropathy, is now an accepted treatment for complex proximal humeral fractures. Few studies have identified whether the outcomes of RSA for shoulder trauma are comparable to those of RSA for shoulder arthritis. METHODS: This is a retrospective, single-institution cohort study of all patients who underwent RSA at our institution between January 2013 and December 2019. In total, 49 patients met the inclusion criteria. As outcomes, we evaluated the 1-year American Shoulder and Elbow Surgeons (ASES) and Constant shoulder scores, postoperative shoulder range of motion, intra- and postoperative complications, and cumulative revision rate. The patients were grouped based on preoperative diagnosis to compare postoperative outcomes across two broad groups. RESULTS: The median follow-up period was 32.8 months (interquartile range, 12.6-66.6 months). The 1-year visual analog scale, range of motion, and Constant and ASES functional scores were comparable between RSAs performed to treat shoulder trauma and that performed for arthritis. The overall complication rate was 20.4%, with patients with a preoperative diagnosis of arthritis having significantly more complications than those with a preoperative diagnosis of trauma (34.8% vs. 7.7%). CONCLUSIONS: Patients who underwent RSA due to a proximal humeral fracture or dislocation did not fare worse than those who underwent RSA for arthritis at 1 year, in terms of both functional and radiological outcomes.