Growth requirements of endothelial cells in culture: variations in serum and amino acid concentrations

Zinc inhibits apoptosis and maintains NEP downregulation, induced by ropivacaine, in HaCaT cells

Zinc (Zn), a cell-protective metal against various toxic compounds, is the key agent for neutral endopeptidase (NEP) functional structure. NEP is a zinc metalloenzyme which degrades endogenous opioids and is expressed in human keratinocytes (HaCaT). Ropivacaine, a widely used opiate local anaesthetic, exerts cell toxic and apoptotic effects against HaCaT cells. The aim of the present study is to investigate whether zinc modulates the effects of ropivacaine on proliferation, viability, apoptosis and NEP expression in HaCaT cells. To investigate the role of ropivacaine in NEP function, HaCaT cells overexpressing NEP were generated via cell transfection with plasmids carrying NEP cDNA. Ropivacaine's anti-proliferative effect was tested by Neubauer's chamber cell counting, and induction of cell death was demonstrated by trypan blue exclusion assay. Apoptosis due to ropivacaine was tested via DNA fragmentation and poly-ADP-ribose-polymerase (PARP) cleavage. NEP and PARP expression was performed by western blot analysis. Results showed that zinc (15 μΜ) inhibited proliferation and cell death induction by ropivacaine (0.5, 1 and 2 mM) (p < 0.05) as well as apoptosis induced by the drug (0.5 and 1 mM) in HaCaT cells. Ropivacaine (1.0, 2.0 and 5.0 mM) downregulated NEP expression in the presence of zinc (15 μΜ) while NEP overexpression enhanced ropivacaine's apoptotic effect. In conclusion, the abilities of zinc to inhibit the toxic and apoptotic effects of ropivacaine, to maintain NEP downregulation induced by the drug and, consequently, to enhance its anaesthetic result suggest that zinc may have a significant role in pain management and tissue protection.

Effects of different calcium, magnesium, and zinc concentrations supplemented on hepatopancreatic cell proliferation of kuruma prawn, Penaeus japonicus

The effects of different calcium (Ca(2+)), magnesium (Mg(2+)), and zinc (Zn(2+)) concentrations supplemented on hepatopancreatic cell proliferation of kuruma prawn, Penaeus japonicus was studied. The culture system consists of medium 199 (M 199) supplemented with 0.060 mol/L NaCl, 1.011 g/L glucose, 1,000 UI/ml penicillin, 1,000 μg/ml treptomycin, heat inactivated fetal calf serum (FCS) 20% for primary cell culture and 10% for subculture. The RNA/DNA ratio of the cell cultures was measured. The results show that the cell division of hepatopancreatic cells of P. japonicus was enhanced by the optimal concentration of inorganic salt (Ca(2+), 1.0 g/L; Mg(2+), 5.0 g/L; Zn(2+), 80 μg/L). The hepatopancreatic cell culture system and improved culture conditions described here will be very useful for in vitro experiments to study viruses responsible for infections in shrimp leading to tremendous economic losses.

Effect of different mitogens and serum concentration on HUVEC morphology and characteristics: implication on use of higher passage cells

Human umbilical vein endothelial cells (HUVEC) were cultured in two different media, viz. the commonly used M199 containing 20% fetal bovine serum (FBS) and endothelial cell growth factor and a defined media EGM-2 containing 2% FBS along with growth supplements in known concentrations. The purpose of this study was to determine the effect of different media on the growth potential and cell morphology in subsequent passages. We have established that a dual coating of gelatin and human fibronectin extracellular matrix provides optimal cell attachment. Growth rate for primary culture was almost double in defined media. For secondary culture a two fold higher proliferation rate was observed in defined EGM-2 media. Histological studies were done using phase contrast, confocal and scanning electron microscopy which showed that cells cultured in M199 started losing their morphological characteristic from 3rd passage and after 6th passage appeared to come in senescent stage, while in case of defined media there was no change observed in the cells up to 10th passage. A significant difference was found in the expression of soluble intracellular adhesion molecule-1 (sICAM-1) which is an endothelial cell marker on cells cultured in different media. Additionally it was observed that exposure duration to trypsin-EDTA during cell detachment also plays an important role in maintaining cell morphological characteristics. These results show that significant morphological changes appear in higher order passages if cells are grown in routine medium for a long time and therefore may not be suitable for cell signaling experiments.

A protocol for isolation and culture of human umbilical vein endothelial cells

We describe a protocol for easy isolation and culture of human umbilical vein endothelial cells (HUVECs) to supply every researcher with a method that can be applied in cell biology laboratories with minimum equipment. Endothelial cells (ECs) are isolated from umbilical vein vascular wall by a collagenase treatment, then seeded on fibronectin-coated plates and cultured in a medium with Earles' salts and fetal calf serum (FCS), but without growth factor supplementation, for 7 days in a 37 degrees C-5% CO2 incubator. Cell confluency can be monitored by phase-contrast microscopy; ECs can be characterized using cell surface or intracellular markers and checked for contamination. Various protocols can be applied to HUVECs, from simple harvesting to a particular solubilization of proteins for proteomic analysis.

Taurine supplementation of a low protein diet fed to rat dams normalizes the vascularization of the fetal endocrine pancreas

In rats, an isoenergetic low protein diet (LP) given throughout gestation perturbs the development of the endocrine pancreas by reducing beta-cell mass and islet vascularization at birth. Taurine, an important amino acid during development, has been found to be low in fetal and maternal plasma. When added to a LP diet, taurine normalizes beta-cell mass. Therefore, we investigated the ability of taurine to correct altered islet vascularization. Rats were given 20% [control (C)] or 8% (LP) protein in the diet with or without supplementation with 25 g/L taurine (T) in drinking water (C+T and LP+T) during gestation and lactation. Immunostaining for vascular endothelial growth factor (VEGF) and fetal liver kinase-1 (Flk-1), a VEGF receptor, was performed on fetal and neonatal pancreatic sections. Blood vessel density and blood vessel number were analyzed morphometrically on semi-thin sections. Taurine supplementation restored a normal volume and numerical density of vessels in fetal islets. The number of cells showing immunoreactivity for VEGF and Flk-1 was reduced by 33 and 45%, respectively, in islet cells from LP fetuses. In 1-mo-old pups, VEGF-positive cells remained decreased by nearly 22%. Both VEGF and Flk-1 were restored in pancreatic endocrine cells of fetuses and pups given taurine. The LP diet induced a threefold overexpression of Flk-1 in ductal cells, which contain precursors of beta cells. However, taurine supplementation was without effect. In conclusion, underexpression of VEGF and Flk-1 is associated with the lower fetal islet vascularization induced by the maternal malnutrition. The addition of taurine to the maternal diet prevents such damage and has a potential role in islet vasculogenesis.

Endothelial cell culture: protocol to obtain and cultivate human umbilical endothelial cells

Endothelial cells play a key role in prominent immunological and pathological processes such as leukocyte trafficking, inflammation, atheroma or cancer cell metastasis. Umbilical veins are probably the most widely used source for human endothelial cells, since they are more easily available than many other vessels, they are free from any pathological process and they are physiologically more relevant than many established cell lines. Here, we describe a standard protocol for preparation, maintenance and quality control of these cells.

Glutamine protects mitochondrial structure and function in oxygen toxicity

Glutamine is an important mitochondrial substrate implicated in the protection of cells from oxidant injury, but the mechanisms of its action are incompletely understood. Human pulmonary epithelial-like (A549) cells were exposed to 95% O2 for 4 days in the absence and presence of glutamine. Cell proliferation in normoxia was dependent on glutamine, and glutamine deprivation markedly accelerated cell death in hyperoxia. Glutamine significantly increased cellular ATP levels in normoxia and prevented the loss of ATP in hyperoxia seen in glutamine-deprived cells. Mitochondrial membrane potential as assessed by flow cytometry with chloromethyltetramethylrosamine was increased by glutamine in hyperoxia-exposed A549 cells, and a glutamine dose-dependent increase in mitochondrial membrane potential was detected. Glutamine-supplemented, hyperoxia-exposed cells had a higher O2 consumption rate and GSH content. Electron and fluorescence microscopy revealed that, in hyperoxia, glutamine protected cellular structures, especially mitochondria, from damage. In hyperoxia, activity of the tricarboxylic acid cycle enzyme alpha-ketoglutarate dehydrogenase was partially protected by its indirect substrate, glutamine, indicating a mechanism of mitochondrial protection.

A low-protein isocaloric diet during gestation affects brain development and alters permanently cerebral cortex blood vessels in rat offspring

In humans, low birth weight is associated with nonfatal stroke, cardiovascular disease and diabetes at adulthood. The aim of this study was to investigate in rats the effect of early protein restriction, inducing low birth weight, on brain and endocrine pancreas vascularization at birth and to study if such alterations lasted until adulthood. Pregnant rats were fed either 20 or 8% protein isocaloric diets. Control newborns were nursed by their dams fed the 20% protein diet and low protein (LP) pups by dams fed either the 8 or 20% protein diet. The diets given during lactation were maintained until adulthood. The blood vessel density of cerebral cortex analyzed by morphometry in 3-d-old pups from dams fed the 8% protein diet was lower than in control (C). It remained lower at adulthood whether a LP or a C diet was given postnatally. Reduction of vascularization at adulthood induced by the LP diet limited to fetal life seems characteristic for the brain since vascularization of islets of Langerhans was reduced in neonates but normalized at adulthood by a C diet postnatally. Body and brain weights were lower in LP pups and adults. DNA concentration was lower in forebrain and higher in cerebellum in LP pups. In brain of LP adults, DNA, protein, cholesterol and phospholipid concentrations were lower and were restored at adulthood by a normal diet after birth. In conclusion, cerebral cortex of offspring exposed to a LP isocaloric diet during fetal development showed reduced vascularization which remained throughout life.