Can Whole Spine Magnetic Resonance Imaging Predict Radiographic Progression and Inflammatory Activity in Axial Spondyloarthritis?

Prochondrogenic effect of decellularized extracellular matrix secreted from human induced pluripotent stem cell-derived chondrocytes

Cartilage is mainly composed of chondrocytes and the extracellular matrix (ECM), which exchange important biochemical and biomechanical signals necessary for differentiation and homeostasis. Human articular cartilage has a low ability for regeneration because it lacks blood vessels, nerves, and lymphatic vessels. Currently, cell therapeutics, including stem cells, provide a promising strategy for cartilage regeneration and treatment; however, there are various hurdles to overcome, such as immune rejection and teratoma formation. In this study, we assessed the applicability of the stem cell-derived chondrocyte ECM for cartilage regeneration. Human induced pluripotent stem cell (hiPSC)-derived chondrocytes (iChondrocytes) were differentiated, and decellularized ECM (dECM) was successfully isolated from cultured chondrocytes. Isolated dECM enhanced in vitro chondrogenesis of iPSCs when recellularized. Implanted dECM also restored osteochondral defects in a rat osteoarthritis model. A possible association with the glycogen synthase kinase-3 beta (GSK3β) pathway demonstrated the fate-determining importance of dECM in regulating cell differentiation. Collectively, we suggested the prochondrogenic effect of hiPSC-derived cartilage-like dECM and offered a promising approach as a non-cellular therapeutic for articular cartilage reconstruction without cell transplantation. STATEMENT OF SIGNIFICANCE: Human articular cartilage has low ability for regeneration and cell culture-based therapeutics could aid cartilage regeneration. Yet, the applicability of human induced pluripotent stem cell-derived chondrocyte (iChondrocyte) extracellular matrix (ECM) has not been elucidated. Therefore, we first differentiated iChondrocytes and isolated the secreted ECM by decellularization. Recellularization was performed to confirm the pro-chondrogenic effect of the decellularized ECM (dECM). In addition, we confirmed the possibility of cartilage repair by transplanting the dECM into the cartilage defect in osteochondral defect rat knee joint. We believe that our proof-of-concept study will serve as a basis for investigating the potential of dECM obtained from iPSC-derived differentiated cells as a non-cellular resource for tissue regeneration and other future applications.

Syndesmophyte Growth in Ankylosing Spondylitis: from Laboratory to Bedside

PURPOSE OF REVIEW

This study aims to review recent studies on risk factors for syndesmophyte growth in ankylosing spondylitis (AS) and on treatment effects.

RECENT FINDINGS

New genetic studies, including a genome-wide association study, provided only limited evidence of specific genetic associations with radiographic severity. Measures of inflammation, including vertebral osteitis and C-reactive protein level, were strongly associated with radiographic progression, while studies of adipokines had mixed results. Mesenchymal stem cells from HLA-B27 positive AS patients were found to promote vertebral ossification via a pathway of B27 misfolding, retinoic acid receptor-β activation, and increased bone alkaline phosphatase. Low vertebral trabecular bone density is associated with syndesmophyte growth, with reciprocal effects when bridged. Several observational studies suggested radiographic severity was reduced by treatment with tumor necrosis factor inhibitors, particularly when longer than 2 years. Syndesmophyte development in AS is the result of a complex, incompletely understood, interplay of inflammatory and mechanical factors.

Comparison of Perioperative Outcomes in Patients Undergoing Short-Level Lumbar Fusion Surgery After Implementing Enhanced Recovery After Surgery: A Propensity Score Matching Analysis Focusing on Young-Old and Old-Old

Background

There were exponentially increased studies focused on revealing the satisfactory outcomes after implementing enhanced recovery after surgery (ERAS) in patients undergoing lumbar fusion surgery. However, little attention has been paid to the impact of chronologic age alone on perioperative outcomes.

Methods

In the present study, patients were dichotomized into two groups: young-old (65-79 years), and old-old (80 years and older). Given the heterogeneity and age-related comorbidities in this population and the need to compare similar groups, we performed propensity score matching for gender, body mass index (BMI), operation time, American Society of Anesthesiologists (ASA) grade, Charlson Comorbidity Index (CCI), fusion levels and frail status. Perioperative outcomes were compared between two groups.

Results

In our study, we found there were significant discrepancies in length of stay (LOS) (7.17 ± 2.81 vs 8.11 ± 3.57 days, p = 0.031) and postoperative nausea and vomiting (3.7% vs 11.0%, p = 0.038); however, there were no significant differences in C-reactive protein (21.50 ± 26.52 vs 19.22 ± 22.04 mg/L, p = 0.490), overall complication rates (24.8% vs 33.0%, p = 0.179), ambulation time (2.89 ± 1.34 vs 2.55 ± 1.49 days, p = 0.078) or removal of urinary catheter time (2.47 ± 1.44 vs 2.32 ± 1.40 days, p = 0.446).

Conclusion

There were few differences in perioperative outcomes between young-old and old-old groups. Despite similar postoperative complication rates, the old-old group might experience longer LOS when complications occur. More importantly, current outcomes suggested that chronologic age alone does not appear to have the capacity to reflect the tolerance of elderly patients to surgery.

The Impact of Frailty on Perioperative Outcomes in Patients Receiving Short-Level Posterior Lumbar Interbody Fusion: A Stepwise Propensity Score Matching Analysis

Background

There are many studies on the impact of frailty on postoperative complications; however, there are few studies focusing on stepwise propensity score matching (PSM) to offset the influence of age.

Methods

We gathered data for patients undergoing short-level posterior lumbar interbody fusion from January to December 2021. According to the Fried frailty phenotype, we categorized patients into non-frail, pre-frail, and frail groups, then, stepwise PSM for age, sex, American Society of Anesthesiologists (ASA) and fusion levels were performed to keep comparable clinical data between groups. Univariate and multivariate logistic regressions were used to determine the impact of clinical demographics on postoperative complications.

Results

A total of 559 consecutive patients with complete medical records were enrolled (237 males and 322 females; mean age 72.55 ± 5.86 years). After PSM, we found that pre-frail patients were more vulnerable to develop urinary retention (p = 0.031) and surgical site infections (p = 0.021) than non-frail patients. Longer length of stay (LOS), delayed ambulation and removal of urinary catheter times were observed in pre-frail patients. However, there was a significant difference only in LOS between pre-frail and frail patients. Binary logistic regression revealed that C-reactive protein (CRP) and frail status were independently associated with postoperative complications between non-frail and pre-frail patients, while only CRP was independently correlated with complications between pre-frail and frail patients.

Conclusion

After PSM, we found higher rates of urinary retention and surgical site infections in pre-frail patients than in non-frail patients. CRP was independently related to postoperative complications, while frail status was only independently associated with postoperative complications between pre-frail and non-frail patients. Pre-frail/frail patients tended to have more severe stress responses than non-frail patients.