A consensus research agenda for optimising nasal drug delivery

Nasal drug delivery has specific challenges which are distinct from oral inhalation, alongside which it is often considered. The next generation of nasal products will be required to deliver new classes of molecule, e.g. vaccines, biologics and drugs with action in the brain or sinuses, to local and systemic therapeutic targets. Innovations and new tools/knowledge are required to design products to deliver these therapeutic agents to the right target at the right time in the right patients. We report the outcomes of an expert meeting convened to consider gaps in knowledge and unmet research needs in terms of (i) formulation and devices, (ii) meaningful product characterization and modeling, (iii) opportunities to modify absorption and clearance. Important research questions were identified in the areas of device and formulation innovation, critical quality attributes for different nasal products, development of nasal casts for drug deposition studies, improved experimental models, the use of simulations and nasal delivery in special populations. We offer these questions as a stimulus to research and suggest that they might be addressed most effectively by collaborative research endeavors

Dynamical effects of subducting ridges: Insights from 3-D laboratory models

We model the subduction of buoyant ridges and plateaus to study their effect on slab dynamics. Oceanic ridges parallel to the trench have a stronger effect on the process of subduction because they simultaneously affect a longer trench segment. Large buoyant slab segments sink more slowly into the asthenosphere, and their subduction result in a diminution of the velocity of subduction of the plate. We observe a steeping of the slab below those buoyant anomalies, resulting in smaller radius of curvature of the slab, that augments the energy dissipated in folding the plate and further diminishes the velocity of subduction. When the 3D geometry of a buoyant plateau is modelled, the dip of the slab above the plateau decreases, as a result of the larger velocity of subduction of the dense "normal" oceanic plate on both sides of the plateau. Such a perturbation of the dip of the slab maintains long time after the plateau has been entirely incorporated into the subduction zone. We compare experiments with the present-day subduction zone below South America. Experiments suggest that a modest ridge perpendicular to the trench such as the present-day Juan Fernandez ridge is not buoyant enough to modify the slab geometry. Already subducted buoyant anomalies within the oceanic plate, in contrast, may be responsible for some aspects of the present-day geometry of the Nazca slab at depth

An siRNA Screen in Pancreatic Beta Cells Reveals a Role for Gpr27 in Insulin Production

The prevalence of type 2 diabetes in the United States is projected to double or triple by 2050. We reasoned that the genes that modulate insulin production might be new targets for diabetes therapeutics. Therefore, we developed an siRNA screening system to identify genes important for the activity of the insulin promoter in beta cells. We created a subclone of the MIN6 mouse pancreatic beta cell line that expresses destabilized GFP under the control of a 362 base pair fragment of the human insulin promoter and the mCherry red fluorescent protein under the control of the constitutively active rous sarcoma virus promoter. The ratio of the GFP to mCherry fluorescence of a cell indicates its insulin promoter activity. As G protein coupled receptors (GPCRs) have emerged as novel targets for diabetes therapies, we used this cell line to screen an siRNA library targeting all known mouse GPCRs. We identified several known GPCR regulators of insulin secretion as regulators of the insulin promoter. One of the top positive regulators was Gpr27, an orphan GPCR with no known role in beta cell function. We show that knockdown of Gpr27 reduces endogenous mouse insulin promoter activity and glucose stimulated insulin secretion. Furthermore, we show that Pdx1 is important for Gpr27's effect on the insulin promoter and insulin secretion. Finally, the over-expression of Gpr27 in 293T cells increases inositol phosphate levels, while knockdown of Gpr27 in MIN6 cells reduces inositol phosphate levels, suggesting this orphan GPCR might couple to Gq/11. In summary, we demonstrate a MIN6-based siRNA screening system that allows rapid identification of novel positive and negative regulators of the insulin promoter. Using this system, we identify Gpr27 as a positive regulator of insulin production

Correlation of adrenomedullin gene expression in peripheral blood leukocytes with severity of ischemic stroke

Human adrenomedullin (ADM), a 52-amino acid peptide, belongs to the calcitonin/calcitonin gene-related peptide (CGRP)/amylin peptide family. ADM acts as a multifunctional regulatory peptide and is upregulated in response to hypoxia. Previous microarray studies have found increased ADM gene (ADM) expression in peripheral blood cells of patients with stroke, however, it is unknown if an increased ADM level is correlated with severity of human ischemic stroke. This study investigated ADM expression in peripheral blood leukocytes (PBL) of healthy controls and subjects at day 1, week 1 and week 3 postacute ischemic stroke using rtPCR methodology. We found that ADM expression was significantly upregulated on the first day of stroke compared to the healthy subjects and the disease controls; the levels remained elevated for up to week 3. Further, ADM expression at day 1 was correlated with stroke severity measured by the National Institute of Healthy Stroke Scale (NIHSS), the modified Barthel Index (mBI) and the modified Rankin Scale (mRS). This could indicate that ADM expression level is related to the severity of tissue damage. We suggest that increased ADM expression in PBL after acute ischemic stroke is most likely to indicate that these cells have been subjected to hypoxia and that the magnitude of expression is likely to be related to the volume of hypoxic tissue. Hypoxia can affect lymphocytes function and could affect the immune response to stroke. The correlation of ADM expression level with the measures of stroke severity implicates ADM - a potential blood bio-marker in studies of ischemic stroke

The ADMR Receptor Mediates the Effects of Adrenomedullin on Pancreatic Cancer Cells and on Cells of the Tumor Microenvironment

Adrenomedullin (AM) is highly expressed in pancreatic cancer and stimulates pancreatic cancer cells leading to increased tumor growth and metastasis. The current study examines the role of specific AM receptors on tumor and cells resembling the tumor microenvironment (human pancreatic stellate--HPSC, human umbilical vein-- HUVEC and mouse lung endothelial cells--MLEC).AM receptors ADMR and CRLR were present in HPSC, HUVEC and MLECs while PDAC cells possessed only ADMR receptors as assessed by RT-PCR and western blotting. All cell lines expressed and secreted AM as indicated by ELISA. The growth of each of the cell lines was stimulated by exogenous AM and inhibited by the antagonist AMA. AM also stimulated in vitro angiogenesis assessed by polygon formation of endothelial cell lines. SiRNA-mediated silencing of ADMR, but not CRLR, reduced basal growth of all cells examined and reduced polygon formation of endothelial cells in vitro. Orthotopic tumors developed with shADMR bearing cancer cells had dramatically reduced primary tumor volume (>90%) and lung and liver metastasis compared to shControl bearing cells. To validate ADMR as a potential therapeutic target, in vivo studies were conducted using neutral nanoliposomes to systemically deliver human siRNA to ADMR to silence human cancer cells and mouse siRNA to ADMR to silence mouse tumor stromal cells. Systemic silencing of both human and mouse ADMR had no obvious adverse effects but strongly reduced tumor development.ADMR mediates the stimulatory effects of AM on cancer cells and on endothelial and stellate cells within the tumor microenvironment. These data support the further development of ADMR as a useful target treatment of pancreatic cancer

Elevated circulating levels of succinate in human obesity are linked to specific gut microbiota

Gut microbiota-related metabolites are potential clinical biomarkers for cardiovascular disease (CVD). Circulating succinate, a metabolite produced by both microbiota and the host, is increased in hypertension, ischemic heart disease, and type 2 diabetes. We aimed to analyze systemic levels of succinate in obesity, a major risk factor for CVD, and its relationship with gut microbiome. We explored the association of circulating succinate with specific metagenomic signatures in cross-sectional and prospective cohorts of Caucasian Spanish subjects. Obesity was associated with elevated levels of circulating succinate concomitant with impaired glucose metabolism. This increase was associated with specific changes in gut microbiota related to succinate metabolism: a higher relative abundance of succinate-producing Prevotellaceae (P) and Veillonellaceae (V), and a lower relative abundance of succinate-consuming Odoribacteraceae (O) and Clostridaceae (C) in obese individuals, with the (P + V/O + C) ratio being a main determinant of plasma succinate. Weight loss intervention decreased (P + V/O + C) ratio coincident with the reduction in circulating succinate. In the spontaneous evolution after good dietary advice, alterations in circulating succinate levels were linked to specific metagenomic signatures associated with carbohydrate metabolism and energy production with independence of body weight change. Our data support the importance of microbe-microbe interactions for the metabolite signature of gut microbiome and uncover succinate as a potential microbiota-derived metabolite related to CVD risk

Exercise and bone health across the lifespan

With ageing, bone tissue undergoes significant compositional, architectural and metabolic alterations potentially leading to osteoporosis. Osteoporosis is the most prevalent bone disorder, which is characterised by progressive bone weakening and an increased risk of fragility fractures. Although this metabolic disease is conventionally associated with ageing and menopause, the predisposing factors are thought to be established during childhood and adolescence. In light of this, exercise interventions implemented during maturation are likely to be highly beneficial as part of a long-term strategy to maximise peak bone mass and hence delay the onset of age- or menopause-related osteoporosis. This notion is supported by data on exercise interventions implemented during childhood and adolescence, which confirmed that weight-bearing activity, particularly if undertaken during peripubertal development, is capable of generating a significant osteogenic response leading to bone anabolism. Recent work on human ageing and epigenetics suggests that undertaking exercise after the fourth decade of life is still important, given the anti-ageing effect and health benefits provided, potentially occurring via a delay in telomere shortening and modification of DNA methylation patterns associated with ageing. Exercise is among the primary modifiable factors capable of influencing bone health by preserving bone mass and strength, preventing the death of bone cells and anti-ageing action provided