Serotonin (5-hydroxytryptamine; 5-HT) is thought to regulate neurodevelopmental processes through maternal-fetal interactions that have long-term mental health implications. Dogma states that beyond fetal 5-HT neurons, there are significant maternal contributions to fetal 5-HT during pregnancy1,2, but this has not been tested empirically. To examine putative central and peripheral sources of embryonic brain 5-HT, we used the Pet-1−/− mice in which most dorsal raphe (DR) neurons lack 5-HT3. Measures of 5-HT revealed previously unknown differences in accumulation between the fore- and hindbrain during early and late fetal stages, through an exogenous source of 5-HT. We show that this source is not of maternal origin. Using additional genetic strategies, a new technology for studying placental biology ex vivo, and direct manipulation of placental neosynthesis, we investigated the nature of this exogenous source and uncovered a placental 5-HT synthetic pathway from a maternal tryptophan precursor, in both mice and humans. This study reveals a new, direct role for placental metabolic pathways in modulating fetal brain development and implicates novel maternal-placental-fetal interactions that could underlie the pronounced impact of 5-HT on long-lasting mental health outcomes.

Intra-articular drug delivery has a number of advantages over systemic administration; however, for the past 20 years, intra-articular treatment options for the management of knee osteoarthritis (OA) have been limited to analgesics, glucocorticoids, hyaluronic acid (HA) and a small number of unproven alternative therapies. Although HA and glucocorticoids can provide clinically meaningful benefits to an appreciable number of patients, emerging evidence indicates that the apparent effectiveness of these treatments is largely a result of other factors, including the placebo effect. Biologic drugs that target inflammatory processes are used to manage rheumatoid arthritis, but have failed to translate to OA. A lack of high-level evidence and methodological limitations hinder our understanding of so called ‘stem’ cell therapies and, although the off-label administration of intra-articular cell therapies (such as platelet-rich plasma and bone marrow aspirate concentrate) is common, high-quality clinical data is needed before these treatments can be recommended. A number of promising intra-articular treatments are currently in clinical development in the United States, including small-molecule and biologic therapies, devices, and gene therapies. Although the prospect of new, non-surgical treatments for OA is exciting, the benefits new treatments must be carefully weighed against their costs and potential risks.

P reeclampsia remains a major problem worldwide for mothers and babies. It is estimated that yearly 50 000 women die in developing countries from preeclampsia.1 Careful maternal observation for the signs of preeclampsia and delivery of women with increasingly severe preeclampsia is the cornerstone of management (as it has been for the past 100 years). Maternal mortality is, therefore, much less in developed countries with the capacity for careful perinatal observation, but morbidity is considerable and remains the leading cause of admissions to intensive care for pregnant women.2 Also, the appropriate delivery of women who develop increasingly severe preeclampsia early in gestation accounts for 8% of all preterm births. Why No Advances in Clinical Management?During the past 20 years, there has been an explosion in our knowledge of preeclampsia. The recognition of inflammation, including endothelial dysfunction as potential unifying pathophysiological concepts and the appreciation of the multisystemic nature of preeclampsia, has directed attention away from blood pressure as the sole or even most important pathophysiological issue of preeclampsia. 4 This concept has resulted in recognition of other origins of organ dysfunction. Despite this, we have not managed to affect the management or early recognition of preeclampsia with this information. Large, well-designed multicenter, clinical intervention trials have, at best, demonstrated a minimal effect on outcome except in perhaps the highest risk cases. Attempts to use factors implicated in the pathophysiology of the disorder to predict preeclampsia have also not as yet provided adequate sensitivity and specificity to be adopted for use in routine clinical practice. 5Is There >1 Subtype of Preeclampsia?Why is this? A recurring theme is success in small studies of prediction, prevention, or treatment of preeclampsia, and failure in larger adequately powered multicenter trials. This Abstract-Preeclampsia remains a major problem worldwide for mothers and babies. Despite intensive study, we have not been able to improve the management or early recognition of preeclampsia. At least part of this is because of failure to standardize the approach to studying this complex syndrome. It is possible that within the syndrome there may be different phenotypes with pathogenic pathways that differ between the subtypes. The capacity to recognize and to exploit different subtypes is of obvious importance for prediction, prevention, and treatment. We present a strategy for research to study preeclampsia, which will allow discrimination of such possible subtypes and also allow comparison and perhaps combinations of findings in different studies by standardized data and biosample collection. To make studies relevant to current clinical practice, the definition of preeclampsia can be that currently used and accepted. However, more importantly, sufficient data should be collected to allow other diagnostic criteria to be used and applied retrospectively.To that end, we present what we ...