Pulsed electric fields stimulate microglial transmitter release of VEGF, IL-8 and GLP-1 and activate endothelial cells through paracrine signaling.

As action potentials propagate along an axon, pulsed extracellular electric fields (E-fields) are induced. We investigated the role of E-fields in activating microglia cells and affecting capillary function and found that E-fields control human microglia secretions in concert with purinergic factors. We generated E-fields by applying transcranial pulsed electromagnetic fields (T-PEMF) identical to those appearing outside neurons as action potentials propagate.

Membrane transporters control cerebrospinal fluid formation independently of conventional osmosis to modulate intracranial pressure.

Background: Disturbances in the brain fluid balance can lead to life-threatening elevation in the intracranial pressure (ICP), which represents a vast clinical challenge. Nevertheless, the details underlying the molecular mechanisms governing cerebrospinal fluid (CSF) secretion are largely unresolved, thus preventing targeted and efficient pharmaceutical therapy of cerebral pathologies involving elevated ICP.

Methods: Experimental rats were employed for in vivo determinations of CSF secretion rates, ICP, blood pressure and ex vivo excised choroid plexus for morphological analysis and quantification of expression and activity of various transport proteins.

Rectal Insulin Instillation Inhibits Inflammation and Tumor Development in Chemically Induced Colitis.

Background And Aims: Epithelial expression of the insulin receptor in the colon has previously been reported to correlate with extent of colonic inflammation. However, the impact of insulin signalling in the intestinal mucosa is still unknown. Here, we investigated the effects of inactivating the epithelial insulin receptor in the intestinal tract, in an experimental model of inflammation-induced colorectal cancer.

Cotransporter-mediated water transport underlying cerebrospinal fluid formation.

Cerebrospinal fluid (CSF) production occurs at a rate of 500 ml per day in the adult human. Conventional osmotic forces do not suffice to support such production rate and the molecular mechanisms underlying this fluid production remain elusive. Using ex vivo choroid plexus live imaging and isotope flux in combination with in vivo CSF production determination in mice, we identify a key component in the CSF production machinery.

Evaluating the involvement of cerebral microvascular endothelial Na/K-ATPase and Na-K-2Cl co-transporter in electrolyte fluxes in an in vitro blood-brain barrier model of dehydration.

The blood-brain barrier (BBB) is involved in brain water and salt homeostasis. Blood osmolarity increases during dehydration and water is osmotically extracted from the brain. The loss of water is less than expected from pure osmotic forces, due to brain electrolyte accumulation.

Tumor microenvironment conditions alter Akt and Na/H exchanger NHE1 expression in endothelial cells more than hypoxia alone: implications for endothelial cell function in cancer.

Background: Chronic angiogenesis is a hallmark of most tumors and takes place in a hostile tumor microenvironment (TME) characterized by hypoxia, low nutrient and glucose levels, elevated lactate and low pH. Despite this, most studies addressing angiogenic signaling use hypoxia as a proxy for tumor conditions. Here, we compared the effects of hypoxia and TME conditions on regulation of the Na/H exchanger NHE1, Ser/Thr kinases Akt1-3, and downstream effectors in endothelial cells.

GLP-1 inhibits VEGFA-mediated signaling in isolated human endothelial cells and VEGFA-induced dilation of rat mesenteric arteries.

We investigated the acute effects of glucagon-like peptide-1 (GLP-1), GLP-1(1-36), and GLP-1(7-36) on vascular endothelial growth factor-A (VEGFA)-induced endothelium-dependent signaling and vasodilation. Our hypothesis was that GLP-1 released from intestinal l-cells modulates processes related to PLCγ activation, Src, and endothelial NOS (eNOS) signaling, thereby controlling endothelial vessel tone. By using RT-PCR analysis, we found mRNA for the GLP-1 receptor (GLP-1R) in human dermal microvascular endothelial cells (HDMEC), human retinal microvascular endothelial cells, and rat arteries.

Elevated p16ink4a Expression in Human Labial Salivary Glands as a Potential Correlate of Cognitive Aging in Late Midlife.

Background: The cell-cycle inhibitor and tumor suppressor cyclin dependent kinase inhibitor, p16ink4a, is one of the two gene products of the ink4a/ARF (cdkn2a) locus on chromosome 9q21. Up-regulation of p16ink4a has been linked to cellular senescence, and findings from studies on different mammalian tissues suggest that p16ink4a may be a biomarker of organismal versus chronological age.

Objective: The aim of this study was to examine the immunolocalization pattern of p16ink4a in human labial salivary gland (LSG) tissue, and to analyze whether its expression level in LSGs is a peripheral correlate of cognitive decline in late midlife.

IL-17A potentiates TNFα-induced secretion from human endothelial cells and alters barrier functions controlling neutrophils rights of passage.

Interleukin-17A (IL-17A) is an important pro-inflammatory cytokine that regulates leukocyte mobilization and recruitment. To better understand how IL-17A controls leukocyte trafficking across capillaries in the peripheral blood circulation, we used primary human dermal microvascular endothelial cells (HDMEC) to investigate their secretory potential and barrier function when activated with IL-17A and TNFα. Activation by TNFα and IL-17A causes phosphorylation of p38 as well as IκBα whereby NFκB subsequently becomes phosphorylated, a mechanism that initiates transcription of adhesion molecules such as E-selectin.

IL-27 inhibits lymphatic endothelial cell proliferation by STAT1-regulated gene expression.

Objective: IL-27 belongs to the IL-12 family of cytokines and is recognized for its role in Th cell differentiation and as an inhibitor of tumor angiogenesis. The purpose of this study was to investigate the effect of IL-27 on proliferation of lymphatic endothelial cells to gain insight into the interplay between the immune system and development of the lymphatic system.

Methods: IL-27-stimulated signal transduction in human dermal lymphatic endothelial cells was measured by western blotting and synthesis of CXCL10 and CXCL11 by use of RT-PCR and ELISA.

Collaborative interplay between FGF-2 and VEGF-C promotes lymphangiogenesis and metastasis.

Interplay between various lymphangiogenic factors in promoting lymphangiogenesis and lymphatic metastasis remains poorly understood. Here we show that FGF-2 and VEGF-C, two lymphangiogenic factors, collaboratively promote angiogenesis and lymphangiogenesis in the tumor microenvironment, leading to widespread pulmonary and lymph-node metastases. Coimplantation of dual factors in the mouse cornea resulted in additive angiogenesis and lymphangiogenesis.

IL-20 activates human lymphatic endothelial cells causing cell signalling and tube formation.

IL-20 is an arteriogenic cytokine that remodels collateral networks in vivo, and plays a role in cellular organization. Here, we investigate its role in lymphangiogenesis using a lymphatic endothelial cell line, hTERT-HDLEC, which expresses the lymphatic markers LYVE-1 and podoplanin. Upon stimulation of hTERT-HDLEC with IL-20, we found an increase in the intracellular free calcium concentration, in Akt and eNOS phosphorylations as well as in perinuclear NO production.

IL-20 is an arteriogenic cytokine that remodels collateral networks and improves functions of ischemic hind limbs.

Successful therapeutic angiogenesis for the treatment of ischemic disorders relies on selection of optimal proangiogenic or arteriogenic agents that are able to promote establishment of functional collateral networks. Here, we show that IL-20, a pleiotropic inflammatory cytokine, displays an imperative effect on vascular remodeling. Stimulation of both large and microvascular endothelial cells with IL-20 leads to activation of receptor-dependent multiple intracellular signaling components, including increased phosphorylation levels of JAK2/STAT5, Erk1/2, and Akt; activation of small GTP-binding proteins Rac and Rho; and intracellular release of calcium.

Treatment of knee osteoarthritis with pulsed electromagnetic fields: a randomized, double-blind, placebo-controlled study.

Objective: The investigation aimed at determining the effectiveness of pulsed electromagnetic fields (PEMF) in the treatment of osteoarthritis (OA) of the knee by conducting a randomized, double-blind, placebo-controlled clinical trial.

Design: The trial consisted of 2h daily treatment 5 days per week for 6 weeks in 83 patients with knee OA. Patient evaluations were done at baseline and after 2 and 6 weeks of treatment.

Nerve growth factor activates aorta endothelial cells causing PI3K/Akt- and ERK-dependent migration.

Nerve growth factor (NGF) is a well-known neurotrophin. We determined whether NGF can activate endothelial cell migration and signalling that underlie angiogenic processes. We showed that aorta endothelial cells express mRNA for both the receptor tyrosine kinase TrkA and the p75 neurotrophin receptor (p75NTR) that associates with TrkA when signalling occurs.

PDGF-BB induces intratumoral lymphangiogenesis and promotes lymphatic metastasis.

Cancer metastases are commonly found in the lymphatic system. Like tumor blood angiogenesis, stimulation of tumor lymphangiogenesis may require the interplay of several tumor-derived growth factors. Here we report that members of the PDGF family act as lymphangiogenic factors.

Small GTP-binding protein Rac is an essential mediator of vascular endothelial growth factor-induced endothelial fenestrations and vascular permeability.

Background: Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induces both angiogenesis and vascular permeability. Although its angiogenic activity has been well characterized, the signaling pathways of VEGF-induced permeability remain poorly understood.

Methods And Results: Using the mouse corneal micropocket assay, Miles assay, and a combination of cytochemical, electron microscopic, and biochemical assays, we demonstrate that VEGF-induced vascular leakage partly can be separated from its angiogenic activity.

Nitric oxide signalling in salivary glands.

Nitric oxide (NO) plays multiple roles in both intracellular and extracellular signalling mechanisms with implications for health and disease. This review focuses on the role of NO signalling in salivary secretion. Attention will be paid primarily to endogenous NO production in acinar cells resulting from specific receptor stimulation and to NO-regulated Ca2+ homeostasis.

Placenta growth factor-1 antagonizes VEGF-induced angiogenesis and tumor growth by the formation of functionally inactive PlGF-1/VEGF heterodimers.

Tumor growth and metastasis require concomitant growth of new blood vessels, which are stimulated by angiogenic factors, including vascular endothelial growth factor (VEGF), secreted by most tumors. Whereas the angiogenic property and molecular mechanisms of VEGF have been well studied, the biological function of its related homolog, placenta growth factor (PlGF), is poorly understood. Here we demonstrate that PlGF-1, an alternatively spliced isoform of the PlGF gene, antagonizes VEGF-induced angiogenesis when both factors are coexpressed in murine fibrosarcoma cells.

Nitric oxide-induced signalling in rat lacrimal acinar cells.

The aim of the present study was to investigate the physiological role of nitric oxide (NO) in mediating secretory processes in rat lacrimal acinar cells. In addition, we wanted to determine whether the acinar cells possess endogenous nitric oxide synthase (NOS) activity by measuring NO production using the fluorescent NO indicator 4,5-diaminofluorescein (DAF-2). We initiated investigations by adding NO from an external source by means of the NO-donor, S-nitroso-N-acetyl-penicillamine (SNAP).

Adrenoceptor-activated nitric oxide synthesis in salivary acinar cells.

We investigated the cellular regulation of nitric oxide synthase (NOS) activity in isolated acinar cells from rat parotid and human labial salivary glands, using the newly developed fluorescent nitric oxide (NO) indicator, DAF-2. We found that sympathetic stimulation with norepinephrine (NE) caused a strong increase in NO synthesis that was not seen after parasympathetic stimulation with acetylcholine. In rat parotid acinar cells, we furthermore investigated to which extent the NOS activity was dependent on the intracellular free Ca2+ concentration ([Ca2+]i) by simultaneously measuring NO synthesis and [Ca2+]i.

Reduction in the rate of inositol 1,4,5-trisphosphate synthesis in rat parotid acini by lithium.

Stimulation of muscarinic cholinergic receptors on rat parotid acinar cells causes a rapid production of inositol phosphates, with the key metabolic event being the breakdown of phosphatidylinositol 4,5-bisphosphate into inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and diacylglycerol. Here a high-performance liquid chromatographic technique was used to measure the effects of intracellular lithium ions on the amount of various inositol phosphates produced. When acini were stimulated maximally with acetylcholine (ACh), the sum of all inositol phosphates produced followed a monoexponential function with a production rate constant for Ins(1,4,5)P3 of 0.

Nitric oxide and cGMP activate Ca2+-release processes in rat parotid acinar cells.

We characterized the enzymic properties of ADP-ribosyl cyclase in rat parotid acinar cells by using a fluorescence technique. ADP-ribosyl cyclase is capable of synthesizing the Ca2+ -mobilizing nucleotide cADP-ribose (cADPR) from NAD(+) and has previously been shown to be regulated by cGMP via a cGMP-dependent protein kinase (G kinase). We therefore investigated whether NO/cGMP-activated pathways are present in rat parotid acinar cells and whether NO/cGMP signalling exerts control over cellular Ca2+ signalling processes.

Nitric oxide synthesis causes inositol phosphate production and Ca2+ release in rat parotid acinar cells.

The activity of nitric oxide synthase (NOS) in rat parotid acinar cells was measured using a newly synthesized fluorescent NO indicator DAF-2/DA. Our results show that NO production is most effectively stimulated by activation of the beta-adrenergic receptor, and to a minor extent by substance P (SP). NO activates the production of cGMP, an intracellular messenger that has been shown to release Ca2+ from ryanodine-sensitive intracellular stores.