Cite this article: Bone Joint Res 2024;13(3):124–126.

Aims

This study was designed to characterize the recurrence incidence and risk factors of antibiotic-loaded cement spacer (ALCS) for definitive bone defect treatment in limb osteomyelitis.

Intervertebral disc degeneration can lead to physical disability and significant pain, while the present therapeutics still fail to biochemically and biomechanically restore the tissue. Stem cell-based therapy in treating intervertebral disc (IVD) degeneration is promising while transplanting cells alone might not be adequate for effective regeneration. Recently, gene modification and 3D-printing strategies represent promising strategies to enhanced therapeutic efficacy of MSC therapy. In this regard, we hypothesized that the combination of thermosensitive chitosan hydrogel and adipose derived stem cells (ADSCs) engineered with modRNA encoding Interleukin − 4 (IL-4) can inhibit inflammation and promote the regeneration of the degenerative IVD.

Rat ADSCs were acquired from adipose tissue and transfected with modRNAs. First, the kinetics and efficacy of modRNA-mediated gene transfer in mouse ADSCs were analyzed in vitro. Next, we applied an indirect co-culture system to analyze the pro-anabolic potential of IL-4 modRNA engineered ADSCs (named as IL-4-ADSCs) on nucleus pulposus cells.

ModRNA transfected mouse ADSCs with high efficiency and the IL-4 modRNA-transfected ADSCs facilitated burst-like production of bio-functional IL-4 protein. In vitro, IL-4-ADSCs induced increased anabolic markers expression of nucleus pulposus cells in inflammation environment compared to untreated ADSCs.

These findings collectively supported the therapeutic potential of the combination of thermosensitive chitosan hydrogel and IL-4-ADSCs for intervertebral disc degeneration management. Histological and in vivo validation are now being conducted.

Osteoarthritis (OA) is a common age-related degenerative joint disease, affecting 7% of the global population, more than 500 million people worldwide. Exosomes from mesenchymal stem cells (MSCs) showed promise for OA treatment, but the insufficient biological targeting weakens its efficacy and might bring side effects. Here, we report the chondrocyte-targeted exosomes synthesized via click chemistry as a novel treatment for OA.

Exosomes are isolated from human umbilical cord-derived MSCs (hUC-MSCs) using multistep ultracentrifugation process, and identified by electron microscope and nanoparticle tracking analysis (NTA). Chondrocyte affinity peptide (CAP) is conjugated on the surface of exosomes using click chemistry. For tracking, nontagged exosomes and CAP-exosomes are labeled by Dil, a fluorescent dye that highlights the lipid membrane of exosomes. To verify the effects of CAP-exosomes, nontagged exosomes and CAP-exosomes are added into the culture medium of interleukin (IL)-1β-induced chondrocytes. Immunofluorescence are used to test the expression of matrix metalloproteinase (MMP)-13.

CAP-exosomes, compared with nontagged exosomes, are more easily absorbed by chondrocytes. What's more, CAP-exosomes induced lower MMP-13 expression of chondrocytes when compared with nontagged exosomes (p<0.001).

CAP-exosomes show chondrocyte-targeting and exert better protective effect than nontagged exosomes on chondrocyte extracellular matrix. Histological and in vivo validation are now being conducted.

Aims

To fully verify the reliability and reproducibility of an experimental method in generating standardized micromotion for the rat femur fracture model.

Purpose: The purpose of this study was to detect any possible prognostic factors which may affect the spinal deformity progression and their relationships in idiopathic scoliosis.

Methods: The stereo-radiograph of whole spine at each visit was reconstructed with two spinal x-ray images in PA 0° and 20° using DLT techniques. Sequential data sets with 3, 4 or 5 successive values of prognostic factors were extracted from 111 consecutive patients (12.3±2.3 yrs, Cobb angle 30.2±12.4°) and separated into the stable and the progressed groups, based on a progression threshold of Cobb angle 5° and 10°. The prognostic factors included gender, curve pattern, age, curve magnitude, apex location, lateral deviation and spinal growth. Effects of those factors were conducted by comparing them between two groups (statistical significances p< 0.05) and the relationships were determined using Pearson’s correlation coefficient (r).

Results: The progressed subjects were predominantly females (50–79%) with double curves. Double curves progressed on both curves RT and LL at the same times and alternatively. There were no significant differences of initial ages and ages with maximum curve magnitudes between two groups. Initial and maximum curve magnitudes were significantly large in the progressed group, but no significantly different between maximum curve magnitudes in the stable group and initial curve magnitude in the progressed group. High curve apex locations were observed in the progressed group. Initial and maximum apex lateral deviations were clearly different in two groups and correlated with curve magnitudes from well to excellent (r = 0.43–0.98). The relationships between the spinal growth and the curve progressing were not consistent (r = −0.6 – +0.6). There were no evidences to show the significant differences of spinal growths between groups and genders.

Conclusions: Scoliosis progression is case dependent. Double curves dynamically progress between curve regions. Initial curve magnitudes have more significant effect on the progression than initial ages. A great progression can be expected from curves with high apex location. Apex lateral deviations are changing with curve magnitudes and spinal growths and, however, the curve magnitudes are not always increased with spinal growths. Funding: 2 Funding Parties: Alberta Provincial CIHR Training Program in Bone and Joint Health

The pathogenesis of scoliosis progression remains poorly understood. Seventy-two subject data sets, consisting of four successive values of Cobb-angle and lateral deviations at apices for six and twelve-months intervals in the coronal plane, were used to train and test an artificial neural network (ANN) to predict spinal deformity progression. The accuracies of the trained ANN (3-4-1) for training and testing data were within 3.64° (±2.58°) and 4.40° (±1.86°) of Cobb angles, and within 3.59 (±3.96) mm and 3.98 (±3.41) mm of lateral deviations, respectively. The adapted technique for predicting the scoliosis deformity progression has promising clinical applications.

Scoliosis is a common and poorly understood three-dimensional spinal deformity. The study purpose is to predict scoliosis progression at six and twelve months intervals in the future using successive spinal indices with an artificial neural network (ANN).

The adapted ANN technique enables earlier detection of scoliosis progression with high accuracy. Improved prediction of scoliosis progression will impact bracing or surgical treatment decisions, and may decrease hazardous X-ray exposure.

Seventy-two data sets from adolescent idiopathic scoliosis subjects recruited at the Alberta Children’s Hospital were used in this study. Data sets composed of four successive values of Cobb angles and lateral deviations at apices for six and twelvemonth intervals (coronal plane) were extracted to train and test a specific ANN for predicting scoliosis progression.

Progression patterns in Cobb angles (n = 10) and lateral deviations (n = 8) were successfully identified. The accuracies of the trained ANN (3-4-1) with the training and testing data sets were 3.64° (±2.58°) and 4.40° (±1.86°) of Cobb angles, 3.59 (±3.96) mm and 3.98 (±3.41) mm of lateral deviations, respectively. These results are in close agreement with those using cubic spline extrapolation techniques (3.49° ± 1.85° and 3.31 ± 4.22 mm) and adaptive neuro-fuzzy inference system (3.92° ±3.53° and 3.37 ±3.95 mm) for the same testing data.

ANN can be a promising technique for prediction of scoliosis progression with substantial improvements in accuracy over current techniques, leading to potentially important implications for scoliosis monitoring and treatment decisions.

Funding: AHFMR, CIHR, Fraternal Order of Eagles, NSERC, GEOIDE.