Neutrophil elastase (NE) has been reported to be a pro-inflammatory stimulus for macrophages. The aim of the present study was to determine the impact of NE exposure on the human macrophage proteome and evaluate its impact on pro-inflammatory signals. Human blood monocytes from healthy volunteers were differentiated to macrophages and then exposed to either 500 nM of NE or control vehicle for 2 h in triplicate. Label-free quantitative proteomics analysis identified 41 differentially expressed proteins in the NE versus control vehicle datasets. A total of 26 proteins were downregulated and of those, 21 were cell surface proteins. Importantly, four of the cell surface proteins were proteoglycans: neuropilin 1 (NRP1), syndecan 2 (SDC2), glypican 4 (GPC4), and CD99 antigen-like protein 2 (CD99L2) along with neuropilin 2 (NRP2), CD99 antigen (CD99), and endoglin (ENG) which are known interactors. Additional NE-targeted proteins related to macrophage function were also measured including CD40, CD48, SPINT1, ST14, and MSR1. Collectively, this study provides a comprehensive unbiased view of selective NE-targeted cell surface proteins in chronically inflamed lungs.

Background: Patellar instability, the subluxation or dislocation of the patella within the patellofemoral joint, is common in adolescents and can significantly affect their function. This study evaluates conservative management for first-time patellar instability events, discussing rehabilitation strategies and criteria for return to activity/sport. Indications: Conservative management is typically indicated for patients experiencing a first-time patellar dislocation, particularly when there are no osteochondral injuries or significant anatomic abnormalities. Technique Description: Physical therapy management begins with an initial evaluation assessing swelling, core and lower extremity strength, range of motion (ROM), and special tests. This management is divided into 3 phases: acute, intermediate, and late. In the acute phase (0-4 weeks), cryotherapy and compression manage effusion, while early ROM exercises prevent stiffness. The intermediate phase (4-6 weeks) focuses on strengthening dynamic knee stabilizers and incorporating progressive open- and closed-chain exercises. The late phase (6-8 weeks) aims to restore full strength and prepare the patient for return to activity through sports-specific drills and higher-intensity exercises. Results: Conservative management for first-time patellar dislocations shows promising outcomes. Early active ROM and strength training are associated with improved knee function, increased ROM, and higher patient satisfaction. Interventions such as patellar taping and nonrigid bracing provide immediate stability and relief, promoting muscle preservation and improved ROM at subsequent follow-ups. Systematic reviews indicate no significant difference in redislocation rates between partial and full weightbearing protocols, supporting the recommendation to avoid immobilization. Key International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) guidelines emphasize complete healing, neuromuscular training, core strength, and psychological readiness for a safe return to sport. Functional assessments like the Y-balance and triple-hop tests help evaluate limb symmetry and functional readiness before resuming activities. Discussion/Conclusion: Conservative management is a suitable plan for most first-time patellar dislocations. While there is no single best rehabilitation plan, important principles for management include early ROM and strengthening exercises to promote knee function. Patient evaluation and criteria can help establish a safe timeline for returning to sport, ensuring optimal recovery, and minimizing recurrence risk. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.