Publications

BACKGROUND

Since September 2005 the International Committee of Medical Journal Editors has required that trials be registered in accordance with the World Health Organization (WHO) minimum dataset, in order to be considered for publication. The objective is to evaluate registries' and individual trial records' compliance with the 2006 version of the WHO minimum data set.

METHODS

A retrospective evaluation of 21 online clinical trial registries (international, national, specialty, pharmaceutical industry and local) from April 2005 to February 2007 and a cross-sectional evaluation of a stratified random sample of 610 trial records from the 21 registries.

RESULTS

Among 11 registries that provided guidelines for registration, the median compliance with the WHO criteria were 14 out of 20 items (range 6 to 20). In the period April 2005-February 2007, six registries increased their compliance by six data items, on average. None of the local registry websites published guidelines on the trial data items required for registration. Slightly more than half (330/610; 54.1%, 95% CI 50.1% - 58.1%) of trial records completed the contact details criteria while 29.7% (181/610, 95% CI 26.1% - 33.5%) completed the key clinical and methodological data fields.

CONCLUSION

While the launch of the WHO minimum data set seemed to positively influence registries with better standardisation of approaches, individual registry entries are largely incomplete. Initiatives to ensure quality assurance of registries and trial data should be encouraged. Peer reviewers and editors should scrutinise clinical trial registration records to ensure consistency with WHO's core content requirements when considering trial-related publications.

Induction of effective osteoclastogenesis by RANK (receptor activator of NF-kappaB) requires costimulation by ITAM-coupled receptors. In humans, the TREM-2 (triggering receptor expressed on myeloid cells 2) ITAM-coupled receptor plays a key role in bone remodeling, as patients with TREM-2 mutations exhibit defective osteoclastogenesis and bone lesions. We have identified a new rapidly induced costimulatory pathway for RANK signaling that is dependent on TREM-2 and mediated by calcium signaling. TREM-2-dependent calcium signals are required for RANK-mediated activation of calcium/calmodulin-dependent protein kinase (CaMK)II and downstream MEK and ERK MAPKs that are important for osteoclastogenesis. IL-10 inhibited RANK-induced osteoclastogenesis and selectively inhibited calcium signaling downstream of RANK by inhibiting transcription of TREM-2. Down-regulation of TREM-2 expression resulted in diminished RANKL-induced activation of the CaMK-MEK-ERK pathway and decreased expression of the master regulator of osteoclastogenesis NFATc1. These findings provide a new mechanism of inhibition of human osteoclast differentiation. The results also yield insights into crosstalk between ITAM-coupled receptors and heterologous receptors such as RANK, and they identify a mechanism by which IL-10 can suppress cellular responses to TNFR family members.

Kisspeptin is a product of the Kiss1 gene and is expressed in the forebrain. Neurons that express Kiss1 play a crucial role in the regulation of pituitary luteinizing hormone secretion and reproduction. These neurons are the direct targets for the action of estradiol-17beta (E(2)), which acts via the estrogen receptor alpha isoform (ER alpha) to regulate Kiss1 expression. In the arcuate nucleus (Arc), where the dynorphin gene (Dyn) is expressed in Kiss1 neurons, E(2) inhibits the expression of Kiss1 mRNA. However, E(2) induces the expression of Kiss1 in the anteroventral periventricular nucleus (AVPV). The mechanism for differential regulation of Kiss1 in the Arc and AVPV by E(2) is unknown. ER alpha signals through multiple pathways, which can be categorized as either classical, involving the estrogen response element (ERE), or nonclassical, involving ERE-independent mechanisms. To elucidate the molecular basis for the action of E(2) on Kiss1 and Dyn expression, we studied the effects of E(2) on Kiss1 and Dyn mRNAs in the brains of mice bearing targeted alterations in the ER alpha signaling pathways. We found that stimulation of Kiss1 expression by E(2) in the AVPV and inhibition of Dyn in the Arc required an ERE-dependent pathway, whereas the inhibition of Kiss1 expression by E(2) in the Arc involved ERE-independent mechanisms. Thus, distinct ER alpha signaling pathways can differentially regulate the expression of identical genes across different brain regions, and E(2) can act within the same neuron through divergent ER alpha signaling pathways to regulate different neurotransmitter genes.