Refractory shoulder injury related to vaccine administration: correlation with culture presence of Cutibacterium acnes.

Background: Shoulder pain following intramuscular administration of vaccine is common. However, a small number of patients experience prolonged pain and dysfunction atypical to normal transient postvaccination shoulder pain. Shoulder Injury Related to Vaccine Administration (SIRVA) remains incompletely understood, whether a robust immune response to vaccine antigen or inappropriate injection technique with needle placement in synovial or bursal tissue, or some combination of the two. Symptoms overlap with those of Cutibacterium acnes (C. acnes) infection but the relationship between the two, if any, has not been evaluated. Methods: Clinical case files were reviewed for 3 cases of SIRVA with positive cultures for C. acnes were reviewed. Presentation, treatment, and clinical outcomes were compared. Results: In all cases, patients were thin (body mass index < 23), females, who had high injection placement of a vaccine, all patients had positive magnetic resonance imaging findings of increased signal in the subacromial bursa, and/or greater tuberosity. All patients underwent arthroscopic débridement and culture harvest and cultures were positive for C. acnes. A combination of oral and intravenous antibiotics was used, and all patients demonstrated clinical improvement from the preoperative state. Discussion: This case series presents 3 patients with refractory SIRVA who ultimately underwent arthroscopic irrigation and débridement with culture biopsy. Each case had culture results positive for C. acnes and all responded, at least partially, to arthroscopic débridement and intravenous antibiotic therapy. The purpose of this manuscript is to raise awareness of potential coexistence of SIRVA and C. acnes which may be of assistance to surgeons treating refractory cases of SIRVA.

3D microcarrier system for efficient differentiation of human pluripotent stem cells into hematopoietic cells without feeders and serum [corrected].

BACKGROUND: Human embryonic stem cells (hESCs) have been derived and maintained on mouse embryonic fibroblast feeders to keep their undifferentiated status. To realize their clinical potential, a feeder-free and scalable system for large scale production of hESCs and their differentiated derivatives is required. MATERIALS & METHODS: hESCs were cultured and passaged on serum/feeder-free 3D microcarriers for five passages. For embryoid body (EB) formation and hemangioblast differentiation, the medium for 3D microcarriers was directly switched to EB medium. RESULTS: hESCs on 3D microcarriers maintained pluripotency and formed EBs, which were ten-times more efficient than hESCs cultured under 2D feeder-free conditions (0.11 ± 0.03 EB cells/hESC input 2D vs 1.19 ± 0.32 EB cells/hESC input 3D). After replating, EB cells from 3D culture readily developed into hemangioblasts with the potential to differentiate into hematopoietic and endothelial cells. Furthermore, this 3D system can also be adapted to human induced pluripotent stem cells, which generate functional hemangioblasts with high efficiency. CONCLUSION: This 3D serum- and stromal-free microcarrier system is important for future clinical applications, with the potential of developing to a GMP-compatible scalable system.