Epitope prime editing shields hematopoietic cells from CD123 immunotherapy for acute myeloid leukemia.

Acute myeloid leukemia (AML) is a malignant cancer characterized by abnormal differentiation of hematopoietic stem and progenitor cells (HSPCs). While chimeric antigen receptor T (CAR-T) cell immunotherapies target AML cells, they often induce severe on-target/off-tumor toxicity by attacking normal cells expressing the same antigen. Here, we used base editors (BEs) and a prime editor (PE) to modify the epitope of CD123 on HSPCs, protecting healthy cells from CAR-T-induced cytotoxicity while maintaining their normal function. Although BE effectively edits epitopes, complex bystander products are a concern. To enhance precision, we optimized prime editing, increasing the editing efficiency from 5.9% to 78.9% in HSPCs. Epitope-modified cells were resistant to CAR-T lysis while retaining normal differentiation and function. Furthermore, BE- or PE-edited HSPCs infused into humanized mice endowed myeloid lineages with selective resistance to CAR-T immunotherapy, demonstrating a proof-of-concept strategy for treating relapsed AML.

The History of Classification Systems for Periprosthetic Femoral Fractures: A Literature Review.

Periprosthetic femoral fractures (PPFFs) following total hip arthroplasty (THA) present a significant clinical challenge due to their increasing incidence with an aging population and evolving surgical practices. Historically, classifications were primarily based on anatomical fracture location, the stability of the implant, and bone quality surrounding the implant. We critically analyzed 25 classification systems, highlighting the emergence and adaptations of key systems such as the Vancouver classification system (VCS) and the Unified classification system (UCS), which are lauded for their simplicity and effectiveness yet require further refinement. VCS, developed in 1995, categorizes fractures based on the site, implant stability, and bone quality, and remains widely used due to its robust applicability across different clinical settings. Introduced in 2014, UCS expands the VCS to encompass all periprosthetic fractures with additional fracture types, aiming for a universal application. Despite their widespread adoption, these systems exhibit shortcomings, including the incomplete inclusion of all PPFF types and the imprecise assessment of implant stability and surrounding bone loss. These gaps can result in misclassification and suboptimal treatment outcomes. This paper suggests the necessity for ongoing improvements in classification systems to include emerging fracture types and refined diagnostic criteria, ensuring that they remain relevant to contemporary orthopedic practices and continue to facilitate the precise tailoring of treatment to patient-specific circumstances. This comprehensive historical review serves as a foundation for future innovations in classification systems, ultimately aiming to standardize PPFF treatment and improve patient prognosis.

Surgical treatment of specific Unified Classification System B fractures: potentially destabilising lesser trochanter periprosthetic fractures.

To investigate the clinical effects of specific Unified Classification System B (UCS B)-lesser trochanter periprosthetic fractures and determine whether they occur only with non-cemented stems. A retrospective analysis of 28 patients with specific UCS B2 fractures who underwent two surgical treatments, longer stem revision and internal fixation (LSRIF) and open reduction and internal fixation (ORIF), was performed. The patients were assessed at 1, 3, 6, 12, and 24 months and annually thereafter. Fracture healing, complications, Harris Hip Score (HHS), and the Short Form Health Survey questionnaire (SF-36) quality of life score were assessed at each follow-up. At the time of the last follow-up, seven patients had been lost: three were lost to contact, two died, and two were hospitalised elsewhere and unavailable for follow-up. The remaining 21 patients were followed for an average of 49.3 ± 15.4 (range: 24-74.4) months. Their average fracture healing time was 13.5 ± 1.1 (12-15.4) weeks. Complications included three cases (10.71%) of thrombus, one (3.57%) of heart failure, and one (3.57%) of pulmonary infection. There were no revisions due to prosthesis loosening, subsidence, or infection. At the last follow-up, the HHS, SF-36 mental score, and SF-36 physical score were recorded, LSRIF vs. ORIF (82.9 ± 6.6 vs. 74.7 ± 3.9, p = 0.059; 50.9 ± 7.6 vs. 38 ± 1.4, p = 0.012, and 51.7 ± 8.4 vs. 39.7 ± 3.4, p = 0.032, respectively). Specific UCS B2 fractures mostly occur with non-cemented stems. LSRIF with cables is the main treatment, while ORIF is an option for those elderly in poor condition.

Reverse traction with Kirschner wires and bilateral external fixation device combined with minimally invasive plate oseoynthesis technique for tibial plateau fractures of type Schatzker V and VI.

PURPOSE: Complex bicondylar tibial plateau fracture (TPF) has always been a tricky problem for surgeons. We created a novel external device used intraoperatively consisting of Kirschner wires, and combined with minimally invasive plate oseoynthesis (MIPO) technique to treat complex bicondylar TPFs, and the clinical effect and feasibility were further evaluated. METHODS: From March 2016 to February 2021, 49 cases (29 males and 20 females) were identified as bicondylar TPF, the mean age 47.2 (27-69). All patients adopted the device and MIPO technique. A series of score, complications, and radiographs in the follow-up period, from three months, six months, one year, and two years and the last follow-up, were recorded, from visual analogue score (VAS), hospital for special surgery (HSS), and Short-Form 36 (SF-36), containing physical (PCS) and mental (MCS), and Rasmussen score. RESULTS: Forty-seven patients showed good functional recovery. No patients were lost, mean follow-up time was 28.17 ± 2.81 (24.2-35.4) months. Operation time was 89.80 ± 13.46 (58-110) min. At the last follow-up, VAS was 1.3 ± 0.92 (0-4), HHS was 93.10 ± 2.63 (89-99), PCS was 49.20 ± 7.40 (38-65), and MCS was 50.08 ± 4.77 (43-62). Complications were as follows: cutaneous necrosis (3, 6%), asymptomatic arthritis (3, 6%), symptomatic arthritis (1, 2%), and deep venous thrombosis (1, 2%). Mean fracture healing time was 11.82 ± 1.5 (10-15.4) weeks. All patients got recovery without extra surgery and removed the implants at 12.85 ± 0.76 (11.2-15.4) months. CONCLUSION: Temporary traction device of bilateral external fixator combined with MIPO technique was simple and convenient, with a smaller soft-tissue damage, an easier operational approach, and its worth being promoted.

Early surgical treatment of closed reduction and internal fixation for a 30-day old intertrochanteric fracture with hemiplegia after acute stroke: A case report.

RATIONALE: Currently, there are no clear guidelines to determine whether and when to perform surgical hip repair in patients with acute stroke and hip fracture. PATIENT CONCERNS: In this case report, we report a case of 75-year-old woman admitted with left hip pain and limited mobility for 1 month. DIAGNOSES: Patient had a history of acute cerebral infarction 42 days ago, and diagnosed with a left intertrochanteric fracture at another hospital 30 days ago. INTERVENTION: Patient was treated with closed reduction and internal fixation with proximal femoral nail anti-rotation. OUTCOMES: At 2-year follow-up, the patient's basic function was restored. The fracture healed well, and the Harris hip score was 75. LESSONS: Without consistent guidelines, individualized treatment strategies including surgical methods and timing of surgery should be made to weigh the risks and benefits for patients with acute stroke and intertrochanteric fractures.

An Innovative Model of ISS-Based Multiple Fractures and Gastrointestinal Dysfunction Related to c-Kit Protein Expression on Interstitial Cells of Cajal.

OBJECTIVE: Gastrointestinal dysfunction seriously affects the prognosis and quality of life of patients with multiple fractures. However, experimental evidence of this relationship is lacking. Here we describe a newly developed mouse model of postoperative gastrointestinal dysfunction after multiple fractures. METHODS: Trauma severity was assessed using the injury severity score (ISS). Based on the ISS, a multiple fracture model was established in mice as follows: limb fractures with pelvic fractures and multiple rib fractures; limb fractures with multiple rib fractures; closed fracture of both forelegs with pelvic fracture and rib fractures; closed limb fractures; limb fracture with pelvic fracture; spinal fractures; hind leg fractures with pelvic fractures; pelvic fracture with multiple rib fractures; closed fracture of both fore legs with pelvic fracture; and closed fracture of both fore legs with multiple rib fractures. In each model group, gastrointestinal motility was assayed and the histopathology of the small intestine was examined. Western blot and immunohistochemical analyses of jejunal tissue were performed to detect c-kit protein expression, the level of which was compared with that of a control group. The results of ANOVA are expressed as mean ± standard deviation. RESULTS: In mice with multiple fractures, food intake was greatly reduced, consistent with histopathological evidence of an injured intestinal epithelium. The jejunal tissue of mice in groups a, c, f, and h was characterized by extensively necrotic and exfoliated intestinal mucosal epithelium and inflammatory cell infiltration in the lamina propria. In the gastrointestinal function assay, gastrointestinal motility was significantly reduced in groups a, b, c, f, and g; these group also had a higher ISS (p < 0.01). The expression of c-kit protein in groups with gastrointestinal dysfunction was significantly up-regulated (p < 0.001) compared with the control group. The close correlation between c-kit expression and the ISS indicated an influence of trauma severity on gastrointestinal motility. CONCLUSION: Gastrointestinal dysfunction after multiple fractures was successfully reproduced in a mouse model. In these mice, c-kit expression correlated with gastrointestinal tissue dysfunction and might serve as a therapeutic target.