Gene Expression in Glenoid Articular Cartilage Varies Across Acute Instability, Chronic Instability, and Osteoarthritis

Periostin Is a Biomarker for Anterior Shoulder Instability: Proteomic Analysis of Synovial Fluid

BACKGROUND

The incremental biological changes in the synovial microenvironment of the shoulder in acute and chronic instability that may contribute to joint degeneration are poorly understood. Proteomic analysis of synovial fluid in patients with shoulder instability may improve our understanding of proteins that are shed into shoulder synovial fluid after an injury.

HYPOTHESIS

Injury-specific factors such as the direction of instability and the severity of glenoid and humeral bone loss are associated with the proteome of synovial fluid in patients with shoulder instability.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Synovial fluid lavage samples were compared between patients with anterior (n = 12) and posterior (n = 8) instability and those without instability (n = 5). Synovial proteins were identified with liquid chromatography-tandem mass spectrometry. Orthogonal validation of protein targets found to be significant on tandem mass spectrometry was performed in a separate set of prospective patients with Western blotting. Data were processed and analyzed, and P values were adjusted with the Benjamini-Hochberg method for multiple comparisons.

RESULTS

A total of 25 patients were included. Tandem mass spectrometry identified 720 protein groups in synovial fluid of patients with shoulder instability. There were 4 synovial proteins that were significantly expressed in patients with anterior instability relative to posterior instability: periostin (POSTN) (adjusted P value = .03; log fold change [logFc] = 4.7), transforming growth factor beta-induced protein ig-h3 (adjusted P value = .05; logFc = 1.7), collagen type VI alpha-3 chain (adjusted P value = .04; logFc = 2.6), and coagulation factor V (adjusted P value = .04; logFc = -3.3). Among these targets, POSTN showed a moderate correlation with the Hill-Sachs lesion size (r = 0.7). Prospective validation with Western blotting confirmed a significantly higher level of POSTN in synovial fluid of patients with anterior instability (P = .00025; logFc = 5.1).

CONCLUSION

Proteomic analysis enriched our understanding of proteins that were secreted into shoulder synovial fluid of patients with shoulder instability. The identification of POSTN, a proinflammatory catabolic protein involved with tissue remodeling and repair, as a significant target in anterior shoulder instability is a novel finding. Therefore, further study is warranted to determine the role that POSTN may play in the progression of bone loss and posttraumatic osteoarthritis.

CLINICAL RELEVANCE

Proteomic analysis of synovial fluid in patients with shoulder instability improved our understanding of this abnormality after an injury.

Musculoskeletal Biorepository: Establishment, Sustainment, and Tips for Success

A biorepository, also referred to as a "biobank," is a collection of biologic samples that are stored for laboratory research. With the emergence of precision medicine, the importance of leveraging individual patient biomolecular signatures to improve diagnosis, prognosis, and treatment is becoming increasingly recognized. Successful development and sustainment of a biorepository provides the potential for transformative preclinical research. Establishing a biobank requires a team approach with involvement of the institutions' research laboratory team and regulatory body. Execution of research activities requires a coordinated team approach for case identification, consent process, data and specimen collection, specimen processing, and storage and archiving. The advancing fields of precision medicine and orthobiologics provide incredible opportunities for institutions to generate novel lines of inquiry in musculoskeletal diseases through a multiomics approach (genomic, transcriptomic, proteomic, microbiomic). In addition, a biobank is an important component of post-market surveillance for the rapidly emerging field of orthobiologics.

Transcriptomic and machine learning analyses identify hub genes of metabolism and host immune response that are associated with the progression of breast capsular contracture

Capsular contracture is a prevalent and severe complication that affects the postoperative outcomes of patients who receive silicone breast implants. At present, prosthesis replacement is the major treatment for capsular contracture after both breast augmentation procedures and breast reconstruction following breast cancer surgery. However, the mechanism(s) underlying breast capsular contracture remains unclear. This study aimed to identify the biological features of breast capsular contracture and reveal the potential underlying mechanism using RNA sequencing. Sample tissues from 12 female patients (15 breast capsules) were divided into low capsular contracture (LCC) and high capsular contracture (HCC) groups based on the Baker grades. Subsequently, 41 lipid metabolism-related genes were identified through enrichment analysis, and three of these genes were identified as candidate genes by SVM-RFE and LASSO algorithms. We then compared the proportions of the 22 types of immune cells between the LCC and HCC groups using a CIBERSORT analysis and explored the correlation between the candidate hub features and immune cells. Notably, PRKAR2B was positively correlated with the differentially clustered immune cells, which were M1 macrophages and follicular helper T cells (area under the ROC = 0.786). In addition, the expression of PRKAR2B at the mRNA or protein level was lower in the HCC group than in the LCC group. Potential molecular mechanisms were identified based on the expression levels in the high and low PRKAR2B groups. Our findings indicate that PRKAR2B is a novel diagnostic biomarker for breast capsular contracture and might also influence the grade and progression of capsular contracture.

Glenohumeral Osteoarthritis: A Biological Advantage or a Missed Diagnosis?

(1) Background: Osteoarthritis is a degenerative joint disease that is commonly diagnosed in the aging population. Interestingly, the lower extremity joints have a higher published incidence of osteoarthritis than the upper extremity joints. Although much is known about the disease process, it remains unclear why some joints are more affected than others. (2) Methods: A comprehensive literature review was conducted utilizing the search engines PubMed, Google Scholar, and Elsevier from 2014 to 2024, directing our search to osteoarthritis of various joints, with the focus being on glenohumeral osteoarthritis. (3) Results and Discussion: The literature review revealed a publication difference, which may be explained by the inconsistency in classification systems utilized in the diagnosis of shoulder osteoarthritis. For instance, there are six classification systems employed in the diagnosis of glenohumeral osteoarthritis, making the true incidence and, therefore, the prevalence unobtainable. Furthermore, susceptibility to osteoarthritis in various joints is complicated by factors such as joint anatomy, weight-bearing status, and prior injuries to the joint. (4) Conclusions: This review reveals the lack of understanding of shoulder osteoarthritis's true incidence and prevalence while considering the anatomy and biomechanics of the glenohumeral joint. In addition, this is the first paper to suggest a single criterion for the diagnosis of glenohumeral osteoarthritis.