Bone repair using periodontal ligament progenitor cell-seeded constructs.

The success of tissue-engineering therapies is dependent on the ability of scaffolds to guide differentiation of progenitor cells. Here we present a new approach using a biomimetic construct composed of hydroxyapatite modified with an in vitro-derived extracellular matrix (HA-ECM) and seeded with periodontal ligament progenitor cells (PDLCs). The study aimed to investigate the effect of HA-ECM on osteogenic differentiation of PDLCs and in vivo evaluation of the PDLC-seeded HA-ECM constructs using a rat calvarial critical-sized defect model. After flow-cytometric phenotyping of PDLCs for typical mesenchymal stem cell markers, the PDLCs were cultured on HA-ECM or HA alone in osteogenic media and assessed by MTT, alkaline phosphatase (ALP) assays, and real-time qPCR at different time intervals after seeding. New bone formation induced by PDLC-seeded constructs was assessed by histomorphometric analysis at 12 weeks post-operatively. The PDLCs seeded on HA-ECM showed significantly higher ALP activity and up-regulation of bone-related genes. The treatment with PDLC-seeded HA-ECM significantly improved calvarial bone repair, with the highest amount of newly formed bone elicited by cell-seeded constructs cultured for 14 days. Our results highlight the PDLC-seeded HA-ECM constructs as a promising tool for craniofacial bone regeneration.

Timing-dependent effects of restraint stress on eosinophilic airway inflammation in mice.

BACKGROUND: Chronic stress has been proposed to aggravate allergic inflammation, whereas acute stress may have functional beneficial effects. The aim of this study was to investigate the influence of timing of single short restraint stress (RST) in a model of eosinophilic airway inflammation. METHODS: The airways of ovalbumin (OVA)-sensitized mice were exposed to an intranasal OVA challenge. RST was applied in two different ways; either 2 h before (pre-stress) or after (post-stress) the OVA challenge, respectively, or as a combination of stress before and after (double-stress) the OVA challenge. One group of mice was also treated with metyrapone (ME) prior to a pre-stress challenge. The inflammatory cell response was evaluated in bronchoalveolar lavage fluid (BALF), lung and nasal tissue, as well as bone marrow. RESULT: RST applied prior to the OVA challenge (pre-stress) inhibited OVA-induced airway inflammation in BALF and lung tissue, and reduced nasal histopathology compared to unstressed mice. Given as post-stress or double-stress, RST did not affect the inflammation in BALF, lungs or nasal tissue. Pre-treatment with ME prevented the pre-challenge stress evoked decrease in inflammation in BALF and lungs. CONCLUSION: Effects of RST on eosinophilic airway inflammation appear to be strongly dependent on timing and, as could be judged from the ME inhibition pattern, also corticosterone dependent. Hypothalamic-pituitary-adrenal axis activation probably influences eosinophilic inflammation through specific sequences of compartmental activation and thereby timing effects are evident on cellular recruitment pattern during the allergic reaction.

A rare human variation: a major branch of the ulnar artery found in the carpal tunnel.

During a routine anatomic dissection of a 60-year-old female cadaver, a large branch of the ulnar artery in the carpal tunnel was found in the left forearm. This branch crossed the median nerve anteriorly. Guyon's canal contained another branch of the ulnar artery and the ulnar nerve. There was no superficial palmar arch in the left hand. The right forearm was without any vascular anomalies. This anomaly has considerable consequences for surgeons considering endoscopic carpal release, because there is a significant risk of injury to the ulnar artery branch.