Enhancer of Zeste Homolog 2 Inhibition Stimulates Bone Formation and Mitigates Bone Loss Caused by Ovariectomy in Skeletally Mature Mice

Perturbations in skeletal development and bone degeneration may result in reduced bone mass and quality, leading to greater fracture risk. Bone loss is mitigated by bone protective therapies, but there is a clinical need for new bone-anabolic agents. Previous work has demonstrated that Ezh2 (enhancer of zeste homolog 2), a histone 3 lysine 27 (H3K27) methyltransferase, suppressed differentiation of osteogenic progenitors. Here, we investigated whether inhibition of Ezh2 can be leveraged for bone stimulatory applications. Pharmacologic inhibition and siRNA knockdown of Ezh2 enhanced osteogenic commitment of MC3T3 preosteoblasts. Next generation RNA sequencing of mRNAs and real time quantitative PCR profiling established that Ezh2 inactivation promotes expression of bone-related gene regulators and extracellular matrix proteins. Mechanistically, enhanced gene expression was linked to decreased H3K27 trimethylation (H3K27me3) near transcriptional start sites in genome-wide sequencing of chromatin immunoprecipitations assays. Administration of an Ezh2 inhibitor modestly increases bone density parameters of adult mice. Furthermore, Ezh2 inhibition also alleviated bone loss in an estrogen-deficient mammalian model for osteoporosis. Ezh2 inhibition enhanced expression of Wnt10b and Pth1r and increased the BMP-dependent phosphorylation of Smad1/5. Thus, these data suggest that inhibition of Ezh2 promotes paracrine signaling in osteoblasts and has bone-anabolic and osteoprotective potential in adults.

Complication rates of EUS-guided celiac plexus blockade and neurolysis: results of a large case series

BACKGROUND AND STUDY AIMS

Complication rates for EUS-guided celiac plexus blockade (CPB) and celiac plexus neurolysis (CPN) have been largely derived from studies utilizing percutaneous or surgical techniques, with few studies specifically examining rates for EUS-guided CPB and CPN. This study aims to further describe the complication rates of EUS-guided CPB and CPN.

PATIENTS AND METHODS

In a retrospective analysis of a prospectively collected EUS database, tracking patients and complications for a single endosonographer at a tertiary-care teaching hospital, data for consecutive patients between August 2003 and March 2008 undergoing either EUS-guided CPB or CPN were analyzed for indications, methods, and complications. Excellent follow-up data were available for all patients.

RESULTS

189 EUS-CPB and 31 EUS-CPN procedures were done in 128 and 30 patients, respectively (60 men, 98 women). Indications for blockades included chronic pancreatitis (122), relapsing pancreatitis with chronic pain (28), upper abdominal pain of suspected pancreatic origin (37), and suspected (yet unproven) pancreatic cancer with pain (2). Neurolyses were performed for refractory pain from cancer (21) or chronic pancreatitis (10). No prophylactic antibiotics were administered. Acid suppression was not withheld. Complications were defined as procedural side effects treated with anything beyond standard observation. Four complications were observed during clinical follow-up (three after CPB, one after CPN), giving an overall complication rate of 1.8 % (CPB 1.6 %, CPN 3.2 %). Complications included asymptomatic hypotension after neurolysis, retroperitoneal abscess after CPB, and severe self-limited postprocedural pain in two patients after CPB.

CONCLUSIONS

EUS-guided CPB and CPN are reasonably safe procedures with tolerable side-effect profiles and low overall complication rates.