Human fetal placental endothelial cells have a mature arterial and a juvenile venous phenotype with adipogenic and osteogenic differentiation potential.

Growing interest in the sources of origin of blood vessel related diseases has led to an increasing knowledge about the heterogeneity and plasticity of endothelial cells lining arteries and veins. So far, most of these studies were performed on animal models. Here, we hypothesized that the plasticity of human fetal endothelial cells depends on their vascular bed of origin i.e. vein or artery and further that the differences between arterial and venous endothelial cells would extend to phenotype and genotype. We established a method for the isolation of fetal arterial and venous endothelial cells from the human placenta and studied the characteristics of both cell types. Human placental arterial endothelial cells (HPAEC) and human placental venous endothelial cells (HPVEC) express classical endothelial markers and differ in their phenotypic, genotypic, and functional characteristics: HPAEC are polygonal cells with a smooth surface growing in loose arrangements and forming monolayers with classical endothelial cobblestone morphology. They express artery-related genes (hey-2, connexin 40, depp) and more endothelial-associated genes than HPVEC. Functional testing demonstrated that vascular endothelial growth factors (VEGFs) induce a higher proliferative response on HPAEC, whereas placental growth factors (PlGFs) are only effective on HPVEC. HPVEC are spindle-shaped cells with numerous microvilli at their surface. They grow closely apposed to each other, form fibroblastoid swirling patterns at confluence and have shorter generation and population doubling times than HPAEC. HPVEC overexpress development-associated genes (gremlin, mesenchyme homeobox 2, stem cell protein DSC54) and show an enhanced differentiation potential into adipocytes and osteoblasts in contrast to HPAEC. These data provide collective evidence for a juvenile venous and a more mature arterial phenotype of human fetal endothelial cells. The high plasticity of the fetal venous endothelial cells may reflect their role as tissue-resident endothelial progenitors during embryonic development with a possible benefit for regenerative cell therapy.

Heterogeneity of microvascular endothelial cells isolated from human term placenta and macrovascular umbilical vein endothelial cells.

The present study compares some phenotypic and physiologic characteristics of microvascular and macrovascular endothelial cells from within one human organ. To this end microvascular endothelial cells from human full-term placenta (PLEC) were isolated using a new method and compared with macrovascular human umbilical vein endothelial cells (HUVEC) and an SV40-transformed placental venous endothelial cell line (HPEC-A2). PLEC were isolated by enzymatic perfusion of small placental vessels, purified on a density gradient and cultured subsequently. Histological sections of the enzyme-treated vessels showed a selective removal of the endothelial lining in the perfused placental cotyledons. The endothelial identity of the cells was confirmed by staining with the endothelial markers anti-von Willebrand factor, Ulex europaeus lectin and anti-QBEND10. The cells internalized acetylated low-density lipoprotein and did not show immunoreactivity with markers for macrophages, smooth muscle cells and fibroblasts. The spindle-shaped PLEC grew in swirling patterns similar to that described for venous placental endothelial cells. However, scanning electron microscopic examination clearly showed that PLEC remained elongated at the confluent state, in contrast to the more polygonal phenotype of HPEC-A2 and HUVEC that were studied in parallel. The amount of vasoactive substances (endothelin-1,2, thromboxane, angiotensin II, prostacyclin) released into the culture medium and the proliferative response to cytokines was more similar to human dermal microvessels (MIEC) derived from non-fetal tissue than to HUVEC. Potent mitogens such as vascular endothelial growth factors (VEGF121, VEGF165) and basic fibroblast growth factor (FGF-2) induced proliferation of all endothelial cell types. Placental growth factors PIGF-1 and PIGF-2 effectively stimulated cell proliferation on PLEC (142 +/- 7% and 173 +/- 10%) and MIEC (160 +/- 20% and 143 +/- 28%) in contrast to HUVEC (9 +/- 8% and 15 +/- 20%) and HPEC-A2 (15 +/- 7% and 24 +/- 6%) after 48 h incubation time under serum-free conditions. These data support evidence for (1) the microvascular identity of the isolated PLEC described in this study, and (2) the phenotypic and physiologic heterogeneity of micro- and macrovascular endothelial cells within one human organ.

Serial hearing organs in the atympanate grasshopper Bullacris membracioides (Orthoptera, Pneumoridae).

In different insect taxa, ears can be found on virtually any part of the body. Comparative anatomy and similarities in the embryological development of ears in divergent taxa suggest that they have evolved multiple times from ubiquitous stretch or vibration receptors, but the homology of these structures has not yet been rigorously tested. Here we provide detailed analysis of a novel set of hearing organs in a relatively "primitive" atympanate bladder grasshopper (Bullacris membracioides) that is capable of signaling acoustically over 2 km. We use morphological, physiological, and behavioral experiments to demonstrate that this species has six pairs of serially repeated abdominal ears derived from proprioceptive pleural chordotonal organs (plCOs). We demonstrate continuity in auditory function from the five posterior pairs, which are simple forms comprising 11 sensilla and resembling plCOs in other grasshoppers, to the more complex anterior pair, which contains 2000 sensilla and is homologous to the single pair of tympanate ears found in "modern" grasshoppers. All 12 ears are morphologically differentiated, responsive to airborne sound at frequencies and intensities that are biologically significant (tuned to 1.5 and 4 kHz; 60-98 dB SPL), and capable of mediating behavioral responses of prospective mates. These data provide evidence for the transition in function and selective advantage that must occur during evolutionary development of relatively complex organs from simpler precursors. Our results suggest that ancestral insects with simple atympanate pleural receptors may have had hearing ranges that equal or exceed those of contemporary insects with complex tympanal ears. Moreover, auditory capability may be more prevalent among modern insect taxa than the presence of overt tympana indicates.

Chemo-nociceptive signalling from the colon is enhanced by mild colitis and blocked by inhibition of transient receptor potential ankyrin 1 channels.

BACKGROUND AND PURPOSE: Transient receptor potential ankyrin 1 (TRPA1) channels are expressed by primary afferent neurones and activated by irritant chemicals including allyl isothiocyanate (AITC). Here we investigated whether intracolonic AITC causes afferent input to the spinal cord and whether this response is modified by mild colitis, morphine or a TRPA1 channel blocker. EXPERIMENTAL APPROACH: One hour after intracolonic administration of AITC to female mice, afferent signalling was visualized by expression of c-Fos in laminae I-II(o) of the spinal dorsal horn at sacral segment S1. Mild colitis was induced by dextran sulphate sodium (DSS) added to drinking water for 1 week. KEY RESULTS: Relative to vehicle, AITC (2%) increased expression of c-Fos in the spinal cord. Following induction of mild colitis by DSS (2%), spinal c-Fos responses to AITC, but not vehicle, were augmented by 41%. Colonic inflammation was present (increased myeloperoxidase content and disease activity score), whereas colonic histology, locomotion, feeding and drinking remained unchanged. Morphine (10 mg.kg(-1)) or the TRPA1 channel blocker HC-030031 (300 mg.kg(-1)) inhibited the spinal c-Fos response to AITC, in control and DSS-pretreated animals, whereas the response to intracolonic capsaicin (5%) was blocked by morphine but not HC-030031. CONCLUSIONS AND IMPLICATIONS: Activation of colonic TRPA1 channels is signalled to the spinal cord. Mild colitis enhanced this afferent input that, as it is sensitive to morphine, is most likely of a chemonociceptive nature. As several irritant chemicals can be present in chyme, TRPA1 channels may mediate several gastrointestinal pain conditions.

Visceral Afferent Neurons: Role in Gastric Mucosal Protection.

Gastric mucosal homeostasis requires rapid alarm of protective mechanisms in the face of pending injury. This article summarizes the evidence that spinal afferent neurons monitor insults to the gastric mucosa and activate local mechanisms of defense and repair through release of transmitter peptides from their endings in the stomach.