A spectrum of exercise training reduces soluble Aß in a dose-dependent manner in a mouse model of Alzheimer's disease.

Physical activity has long been hypothesized to influence the risk and pathology of Alzheimer's disease. However, the amount of physical activity necessary for these benefits is unclear. We examined the effects of three months of low and high intensity exercise training on soluble Aß40 and Aß42 levels in extracellular enriched fractions from the cortex and hippocampus of young Tg2576 mice. Low (LOW) and high (HI) intensity exercise training animals ran at speeds of 15m/min on a level treadmill and 32 m/min at a 10% grade, respectively for 60 min per day, five days per week, from three to six months of age. Sedentary mice (SED) were placed on a level, non-moving, treadmill for the same duration. Soleus muscle citrate synthase activity increased by 39% in the LOW group relative to SED, and by 71% in the HI group relative to LOW, indicating an exercise training effect in these mice. Soluble Aß40 concentrations decreased significantly in an exercise training dose-dependent manner in the cortex. In the hippocampus, concentrations were decreased significantly in the HI group relative to LOW and SED. Soluble Aß42 levels also decreased significantly in an exercise training dose-dependent manner in both the cortex and hippocampus. Five proteins involved in Aß clearance (neprilysin, IDE, MMP9, LRP1 and HSP70) were elevated by exercise training with its intensity playing a role in each case. Our data demonstrate that exercise training reduces extracellular soluble Aß in the brains of Tg2576 mice in a dose-dependent manner through an up-regulation of Aß clearance.

Characteristics of benign neuroblastic tumors: Is surgery always necessary?

PURPOSE: Ganglioneuroma (GN) and ganglioneuroblastoma-intermixed (GNB-I) represent benign variants of neuroblastic tumors in children; however, differentiating from more aggressive histological variants of GNB including the nodular subtype (GNB-N) prior to resection can be challenging, even with biopsy. Currently, no standard treatment guidelines exist. The purpose of this study was to identify pre-operative characteristics of benign neuroblastic tumors and evaluate outcomes for patients who underwent surgical resection or observation. METHODS: Retrospective chart review of children treated at a single institution between 2009 and 2019 for non-metastatic tumor with a tissue diagnosis of GN, GNB-N or GNB-I. Demographics, imaging, labs, operative details and outcomes were recorded and analyzed. RESULTS: Of 53 patients, 45% were male. The most common tumor location was abdomen (49%), followed by thorax (34%). Forty-five percent had at least one image defined risk factor. Biopsy was performed in 32% (17/53) and upfront surgery in 68% (36/53). Three patients (3/53, 5.6%) with biopsy demonstrating GN tumors were observed due to high surgical risk. Pathology of resected specimens demonstrated GN in 52% (26/50) and GNB-I or GNB-N in 48% (24/50). The majority of GNB tumors (75% (18/24) were GNB-I and 25% (6/24) were GNB-N. Therefore, 88% of the resected tumors were benign spectrum neuroblastic tumors (GN & GNB-I). Seven (7/50, 14%) patients experienced perioperative complication (temporary paralysis, Horner's syndrome, chylothorax, vocal cord paralysis). Recurrence was noted in 1 patient with GN (1/50, 2%) and 3 with GNB-N (3/50, 6%). There were no tumor-related deaths. Patients with GN were older than those with GNB (8.8 years (IQR 6-11.25) vs 5.6 years for GN (IQR 3-7); p = 0.01). GNB tumors were also more likely to have calcifications on imaging (63% vs. 38%, p = .01) and more commonly had MIBG avidity (88% vs 66%, p = .04). There were no significant differences in tumor size or symptoms at presentation. CONCLUSIONS: In children with neuroblastic tumors, older age, CT without tumor calcifications, lack of MIBG avidity, and/or normal urine catecholamines may indicate benign GN. Close observation could be considered for asymptomatic patients meeting these criteria with biopsy-proven GN, with resection reserved for progressive growth or symptom development. However, larger, multicenter studies are needed for further validation. LEVEL OF EVIDENCE: IV.