Citations

OBJECTIVE The goal of this study was to characterize local tumor control (LC), overall survival (OS), and safety of stereotactic radiosurgery for colorectal brain metastasis (CRBM). METHODS Ten international institutions participating in the International Radiosurgery Research Foundation provided data for this retrospective case series. This study included 187 patients with CRBM (281 tumors), with a median age of 62 years and 56.7% being male. Most patients (53.5%) had solitary tumors, although 10.7% had > 5 tumors. The median tumor volume was 2.7 cm3 (IQR 0.22–8.1 cm3), and the median margin dose was 20 Gy (IQR 18–22 Gy). RESULTS The 3-year LC and OS rates were 72% and 20%, respectively. Symptomatic adverse radiation effects occurred in 1.6% of patients. In the multivariate analysis, age > 65 years and tumor volume > 4.0 cm3 were significant predictors of tumor progression (hazard ratio [HR] 2.6, 95% CI 1.4–4.9; p = 0.003 and HR 3.4, 95% CI 1.7–6.9; p < 0.001, respectively). Better performance status (Karnofsky Performance Scale score > 80) was associated with a reduced risk of tumor progression (HR 0.38, 95% CI 0.19–0.73; p = 0.004). Patient age > 62 years (HR 1.6, 95% CI 1.1–2.3; p = 0.03) and the presence of active extracranial disease (HR 1.7, 95% CI 1.1–2.4; p = 0.009) were significantly associated with worse OS. CONCLUSIONS Stereotactic radiosurgery offers a high LC rate and a low rate of symptomatic adverse radiation effects for the majority of CRBMs. The OS and LC favored younger patients with high functional performance scores and inactive extracranial disease.

Abstract Activation of innate immunity in the brain is a prominent feature of Alzheimer's disease (AD). The present study investigated the regulation of innate immunity by young serum in a transgenic AD mouse model. We found that young serum significantly reduced the number of neutrophils and microglial reactivity in the brains of APP/PS1 mice. Neutrophil depletion via Ly6G neutralizing antibodies mimicked the benefits of young serum on AD brain functions. Serum proteomic analysis of young serum revealed significant enrichment of the factors VEGF-A and CXCL1, which are crucial for neutrophil migration and chemotaxis, leukocyte migration, and cell chemotaxis. Intravenously injected VEGF-A reversed Aβ-induced decreases in Cdk5 and increases in CXCL1 in vitro and blocked neutrophil infiltration into the AD brain. Endothelial Cdk5 overexpression conferred an inhibitory effect on CXCL1 and neutrophil infiltration and thereby restored memory in APP/PS1 mice. Our data uncover a previously unknown link between blood-derived VEGF signaling and neutrophil infiltration and provide a rationale for targeting endothelial Cdk5 signaling as a potential therapeutic strategy for AD.