Decellularized extracellular matrix biomaterials for regenerative therapies: Advances, challenges and clinical prospects.

Tissue engineering and regenerative medicine have shown potential in the repair and regeneration of tissues and organs via the use of engineered biomaterials and scaffolds. However, current constructs face limitations in replicating the intricate native microenvironment and achieving optimal regenerative capacity and functional recovery. To address these challenges, the utilization of decellularized tissues and cell-derived extracellular matrix (ECM) has emerged as a promising approach. These biocompatible and bioactive biomaterials can be engineered into porous scaffolds and grafts that mimic the structural and compositional aspects of the native tissue or organ microenvironment, both in vitro and in vivo. Bioactive dECM materials provide a unique tissue-specific microenvironment that can regulate and guide cellular processes, thereby enhancing regenerative therapies. In this review, we explore the emerging frontiers of decellularized tissue-derived and cell-derived biomaterials and bio-inks in the field of tissue engineering and regenerative medicine. We discuss the need for further improvements in decellularization methods and techniques to retain structural, biological, and physicochemical characteristics of the dECM products in a way to mimic native tissues and organs. This article underscores the potential of dECM biomaterials to stimulate in situ tissue repair through chemotactic effects for the development of growth factor and cell-free tissue engineering strategies. The article also identifies the challenges and opportunities in developing sterilization and preservation methods applicable for decellularized biomaterials and grafts and their translation into clinical products.

Initial Fibular Displacement as a Predictor of Medial Clear Space Widening in Weber B Ankle Fractures.

BACKGROUND: The diagnosis of medial ankle instability in Weber B ankle fractures remains controversial. Manual stress and gravity stress radiographs as well as magnetic resonance imaging (MRI) are used, but there is no consensus gold standard. The purpose of this study was to determine the relationship between initial fibular displacement and medial clear space widening on a gravity stress radiograph as a predictor of instability. METHODS: A retrospective review was conducted of all patients with isolated Weber B ankle fractures with both initial injury radiographs and gravity stress view from August 1, 2014, through April 1, 2016. A total of 17 patients were identified. On the mortise view of initial injury radiographs, medial clear space (MCS), superior clear space, lateral fibular displacement (LFDP), and fibular shortening (FS) were measured, and on the lateral view, anterior to posterior fibular gap (A to P FG) was measured. MCS was again measured on the gravity stress view (MCS-W). Statistical analyses identified the correlations of each displacement variable relative to MCS-W as well as the sensitivity and specificity of each parameter. RESULTS: A cutoff point for MCS-W was set as less than 5.0 mm (n = 8) and 5.0 mm or more (n = 9). Strong significant correlations with MCS-W were found for A to P FG (0.84, P < .001), with a trend for LFDP (0.62, P = .008), but no significance with FS (0.38, P = .84). Linear regression analysis revealed significant ability to predict MCS-W for both LFDP ( P = .002) and A to P FG ( P = .001) but not FS. Receiver operating characteristic analysis for A to P FG using a threshold value of 1.0 mm yielded sensitivity and specificity of 100% in predicting an MCS-W of 5.0 mm or more. CONCLUSION: The initial fibular displacement was a strong predictor of MCS-W in Weber B ankle fractures. On lateral radiographs, an A to P FG greater than 1.0 mm showed a sensitivity and specificity of 100% in predicting an MCS-W of 5.0 mm or more on gravity stress view. LEVEL OF EVIDENCE: Level III case series, prognostic.

Acute effects of the Protonics system on patellofemoral alignment: an MRI study.

This study used magnetic resonance imaging (MRI) to determine whether changes in patellofemoral alignment occur after initial treatment with the Protonics exercise device. The first scan was obtained before the device was used. After performing a set of exercises with no resistance on the device the device was removed, and a second scan was obtained. The same set of exercises was again performed with resistance on the device set at the appropriate level, and a final scan was obtained with the device removed. An isometric leg press was maintained as each image was obtained to simulate more closely a functional weight-bearing activity. Subjects were 26 women with complaints of patellofemoral pain. The main outcome measures were: patellar tilt angle, bisect offset, and lateral facet angle. Nonparametric repeated measures analysis of variance tests showed no differences between test conditions for any of the three measures of patellofemoral alignment. We conclude that after an initial treatment session using the Protonics system there is no change in patellofemoral alignment as determined by MRI.