Prenatal inflammation-induced NF-κB dyshomeostasis contributes to renin-angiotensin system over-activity resulting in prenatally programmed hypertension in offspring.

Studies involving the use of prenatally programmed hypertension have been shown to potentially contribute to prevention of essential hypertension (EH). Our previous research has demonstrated that prenatal inflammatory stimulation leads to offspring's aortic dysfunction and hypertension in pregnant Sprague-Dawley rats challenged with lipopolysaccharide (LPS). The present study found that prenatal LPS exposure led to NF-κB dyshomeostasis from fetus to adult, which was characterized by PI3K-Akt activation mediated degradation of IκBα protein and impaired NF-κB self-negative feedback loop mediated less newly synthesis of IκBα mRNA in thoracic aortas (gestational day 20, postnatal week 7 and 16). Prenatal or postnatal exposure of the IκBα degradation inhibitor, pyrollidine dithiocarbamate, effectively blocked NF-κB activation, endothelium dysfunction, and renin-angiotensin system (RAS) over-activity in thoracic aortas, resulting in reduced blood pressure in offspring that received prenatal exposure to LPS. Surprisingly, NF-κB dyshomeostasis and RAS over-activity were only found in thoracic aortas but not in superior mesenteric arteries. Collectively, our data demonstrate that the early life NF-κB dyshomeostasis induced by prenatal inflammatory exposure plays an essential role in the development of EH through triggering RAS over-activity. We conclude that early life NF-κB dyshomeostasis is a key predictor of EH, and thus, NF-κB inhibition represents an effective interventional strategy for EH prevention.

[A 3D-ultrasound imaging system based on back-end scanning mode].

A new scanning mode is proposed that the front-end of the probe is fixed, while the back-end makes fan-shaped, scanning movement. The new scanning mode avoided ribs drawbacks successfully. Based on the new scanning mode a 3D-Ultrasound Images System is accomplished to acquire 2D data of fetusfetus fetusfetus phantom and livers and kidneys, to demonstrates the effectiveness of the new scanning mode.

Fluorescence studies on a designed self-assembling peptide of RAD16-II as a potential carrier for hydrophobic drug.

The self-assembling peptide, RAD16-II (Ac-RARADADARARADADA-NH2), has been shown to have many great applications in nanotechnology and tissue engineering. But few studies have been carried out to study the application of self-assembling peptides as a drug carrier. We used hydrophobic drug pyrene as a model and liposome vesicles to mimic bilayer membranes to study the ability of RAD16-II in drug encapsulation and transfer to lipid vesicles. It was found that this designed self-assembling peptide was able to stabilize hydrophobic drug in aqueous solution and deliver it into lipophilic environment. Analysis of the fluorescence excitation spectra showed that pyrene was present in the crystalline form when stabilized by RAD16-II and was able to be dispersed in egg phosphatidylcholine vesicles. This suggested that pyrene was completely released from RAD-Py mixture into the bilayer membranes. Furthermore, the concentration of pyrene transferred into the vesicles was quantified and its transfer rate was determined. The scanning electron micrograph image showed that pyrene microcrystals and peptide were absorbed by each other and the size of the pyrene-peptide complexes was larger than 10 microm. These data further demonstrated that this type of ionic complementary oligopeptides was able to significantly encapsulate hydrophobic drug and provide a new type of nanomaterials for delivering drugs.

Complete loss of ischaemic preconditioning-induced cardioprotection in mice with partial deficiency of HIF-1 alpha.

AIMS: We investigated whether hypoxia-inducible factor 1 alpha (HIF-1 alpha) plays a role in the acute phase of ischaemic preconditioning (IPC). METHODS AND RESULTS: Hearts from wild-type (WT) mice and mice heterozygous for a null allele at the locus encoding HIF-1 alpha (HET) were subjected to IPC (10-min ischaemia/5 min reperfusion, or two cycles of 5 min ischaemia/5 min reperfusion), followed by 30 min ischaemia and reperfusion. Left ventricular-developed pressure, heart rate, and coronary flow rate were measured continuously. Apoptosis and infarct size were assessed by TUNEL assay, cleaved caspase 3 immunohistochemistry, and triphenyltetrazolium chloride staining. Production of reactive oxygen species (ROS) in isolated cardiac mitochondria was measured by a chemiluminescence assay. The phosphatase and tensin homologue (PTEN) and AKT (protein kinase B) were analysed by immunoblot assay. IPC improved functional recovery and limited infarct size and apoptosis after prolonged ischaemia-reperfusion in WT hearts, but not in HET hearts. Mitochondrial ROS production, PTEN oxidation, and AKT phosphorylation were impaired in HET hearts. WT and HET hearts were protected by adenosine, which acts via an ROS-independent mechanism. CONCLUSION: HIF-1 alpha is required for IPC-induced mitochondrial ROS production and myocardial protection against ischaemia-reperfusion injury.

From bench to bedside: successful translational nanomedicine: highlights of the Third Annual Meeting of the American Academy of Nanomedicine.

The Third Annual Meeting of the American Academy of Nanomedicine (AANM) was held at the University of California San Diego, in San Diego, California during September 7-8, 2007. The meeting was focused on successful translational nanomedicine: from bench to bedside. There were four keynote lectures and eight scientific symposiums in this meeting. The researchers and investigators reported the results and process of current nanomedicine research and approaches to clinical applications. The meeting provided exciting information for nanomedicine clinical-related researches and strategy for further development of nanomedicine research which will be benefits to clinical practice.

Recent advances in basic and clinical nanomedicine.

Nanomedicine is a global business enterprise. Industry and governments clearly are beginning to envision nanomedicine's enormous potential. A clear definition of nanotechnology is an issue that requires urgent attention. This problem exists because nanotechnology represents a cluster of technologies, each of which may have different characteristics and applications. Although numerous novel nanomedicine-related applications are under development or nearing commercialization, the process of converting basic research in nanomedicine into commercially viable products will be long and difficult. Although realization of the full potential of nanomedicine may be years or decades away, recent advances in nanotechnology-related drug delivery, diagnosis, and drug development are beginning to change the landscape of medicine. Site-specific targeted drug delivery and personalized medicine are just a few concepts that are on the horizon.

New technology and clinical applications of nanomedicine.

Nanomedicine is the use of nanotechnology to achieve innovative medical breakthroughs. Nanomedicine, with its broad range of ideas, hypotheses, concepts, and undeveloped clinical devices, is still in its early stage. This article outlines present developments and future prospects for the use of nanotechnology techniques in experimental in vivo and in vitro studies and in engineering nanodevices and biosensors for clinical and investigative use n diagnosis and therapy in the fields of genetics, oncology, cardiology, and dermatology. Toxicologic considerations also are discussed.

Nanomedicine and drug delivery.

This article discusses the use of nanotechnology in drug delivery approaches. Magnetic nanotechnology is finding wide applications in medicine, most notably in MRI and magnetic separation. The impedance biosensor is expected to find applications in monitoring cytokines in cancer, bone turnover markers in osteoporosis, and understanding neural-degenerative diseases.

New advances in nanomedicine: diagnosis and preventive medicine.

This article describes the use of nanobiologic techniques in diagnosis and preventive medicine. It discusses the engineering of fluorescent and bioluminescent proteins to visualize biologic functions; single-molecule measurements of protein structure and function; two-photon microscopy for molecular imaging of the structure and function in living cells and tissues; and imaging ligand-induced protein conformations and interactions by fluorescence in single living cells.

Genetic nanomedicine and tissue engineering.

This article describes current investigative directions in nanotechnology-based medicine. It discusses cell sheet engineering, the molecular design of self-assembling peptide nanomaterials; the reconstitution of membrane protein systems on giant liposomes as artificial cell models, a biochemically engineered molecular communication system, and the use of split-reporter reconstitution analysis to image biomolecules in living cells and animals.

Selective decrease in the DNA base excision repair pathway in squamous cell cancer of the esophagus.

OBJECTIVES: Oxidative damage can lead to a highly mutagenic 8-oxoguanine lesion, which mispairs with adenosine residues, leading to G:C-->T:A transversions. In mammalian cells 8-oxoguanine glycosylase initiates the DNA base excision repair pathway to repair the 8-oxoguanine lesion. To date, there is no information regarding oxidative DNA damage and repair pathways in esophageal cancer. Therefore we designed the current study to demonstrate the DNA damage and repair pathways in esophageal cancer by expression of 8-oxoguanine glycosylase in reflux-induced and mutagen (methyl-n-amyl nitrosamine)-induced DNA damage and apoptosis in esophageal tumors. METHODS: Gastroduodenal reflux was surgically created in male Sprague Dawley rats (n = 120). Half of the animals received methyl-n-amyl nitrosamine. Animals not undergoing operations served as control animals (n = 10). The experiment concluded 30 weeks postoperatively. Immunohistochemistry for 8-oxoguanine and 8-oxoguanine glycosylase was assessed by 2 independent observers. Protein expression was assessed by using the Western blot method. RESULTS: There was significantly more DNA damage in both adenocarcinoma (n = 15) and squamous cell carcinoma (n = 19), as exemplified by positive 8-oxoguanine expression compared with that seen in control animals (P < .05). 8-Oxoguanine glycosylase was several folds upregulated in adenocarcinoma (P < .05), but there was significantly decreased expression in squamous cell carcinoma (P < .01). The apoptosis was assessed as caspase-dependent and caspase-independent pathways, and both were active and correlated well with 8-oxoguanine expression. CONCLUSION: These results demonstrate the selective decrease in the DNA base excision repair pathway in combined reflux and methyl-n-amyl nitrosamine-induced squamous cell cancer of the esophagus.

Duodenal reflux leads to down regulation of DNA mismatch repair pathway in an animal model of esophageal cancer.

BACKGROUND: Gastroduodenal reflux is implicated in esophageal carcinogenesis. This effect is mediated by reactive oxygen species. We hypothesized that this is mediated by DNA mismatch lesion 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoG), which is repaired by the Mut Y homologue (MYH). We tested the effect of reflux, either alone or in combination with the human dietary mutagen methyl-n-amyl nitrosamine (MNAN), on DNA damage in adenocarcinoma and squamous cell cancer of the esophagus in a rat model. METHODS: Reflux was promoted in male Sprague-Dawley rats by duodenoesophageal anastomosis (8 weeks) without gastric bypass. MNAN treatment (25 mg/kg per week intraperitoneally for four doses) commenced at 10 weeks age. Ten animals served as controls. Quantification of 8-oxoG was performed by using immunohistochemistry, and MYH was analyzed by Western blot. Apoptosis was assessed by terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling (TUNEL), cytochrome C, and caspase. RESULTS: Tumors (adenocarcinoma) developed in 15 (50%) of 30 animals with reflux alone; this increased to 26 (86.6%) of 30 when reflux was combined with MNAN treatment, with tumor histology consistent with adenosquamous and squamous cell cancer. DNA damage, as reflected by positive 8-oxoG staining in reflux groups, was significantly increased compared with control (p < 0.01), and this was maximal in tissues with malignant transformation. Protein levels of the DNA repair enzyme MYH were significantly less in tissues subjected to reflux compared with controls (p < 0.05). TUNEL, cytochrome C, and caspase positivity confirmed increased apoptosis in cancer lesions. CONCLUSIONS: Gastroduodenal reflux leads to increased DNA damage and downregulation of the DNA mismatch repair pathway. This pathway has an important role in esophageal carcinogenesis in rats.

Epigallocathechin-3 gallate inhibits cardiac hypertrophy through blocking reactive oxidative species-dependent and -independent signal pathways.

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. Recent in vitro and in vivo studies have suggested that reactive oxygen species (ROS) may play an important role in cardiac hypertrophy. It was therefore thought to be of particular value to examine the effects of antioxidants on cardiac hypertrophy. Epigallocatechin-3-gallate (EGCG) is a major bioactive polyphenol present in green tea and a potent antioxidant. The current study was designed to test the hypothesis that EGCG inhibits cardiac hypertrophy in vitro and in vivo. In this study, we investigated the effects of EGCG on angiotensin II- (Ang II) and pressure-overload-induced cardiac hypertrophy. Our results showed that EGCG attenuated Ang II- and pressure-overload-mediated cardiac hypertrophy. Both reactive oxygen species generation and NADPH oxidase expressions induced by Ang II and pressure overload were suppressed by EGCG. The increased hypertension by pressure overload was almost completely blocked after EGCG treatment. Further studies showed that EGCG inhibited Ang II-induced NF-kappaB and AP-1 activation. Inhibition of the activity of NF-kappaB was through blocking ROS-dependent p38 and JNK signaling pathways, whereas inhibition of AP-1 activation was via blocking EGFR transactivation and its downstream events ERKs/PI3K/Akt/mTOR/p70(S6K). The combination of these actions resulted in repressing the reactivation of ANP and BNP, and ultimately preventing the progress of cardiac hypertrophy. These findings indicated that EGCG prevents the development of cardiac hypertrophy through ROS-dependent and -independent mechanisms involving inhibition of different intracellular signaling transductional pathways.

The mitochondrial K-ATP channel opener, diazoxide, prevents ischemia-reperfusion injury in the rabbit spinal cord.

Paraplegia resulting from ischemia is a catastrophic complication of thoracoabdominal aortic surgery. The current study was designed to investigate the effects of diazoxide (DZ) on mitochondrial structure, neurological function, DNA damage-repair, and apoptosis in spinal cord ischemia-reperfusion injury. Rabbits were subjected to 30 minutes of spinal cord ischemia and reperfusion (1 hour) with or without diazoxide (n = 6 in each group) by clamping and releasing the infrarenal aorta. The neurological functional score was significantly improved in the DZ-treated ischemia-reperfusion injury group. Electron microscopic studies demonstrated that mitochondrial damage in the spinal cord after injury was significantly reduced by DZ. Mitochondrial superoxide and hydrogen peroxide levels were also markedly decreased in the DZ-treated injury group compared with the untreated group. DZ decreased levels of the oxidative DNA damage product 8-oxoG and increased levels of the DNA repair enzyme OGG-1. Furthermore, DZ inhibited apoptosis via caspase-dependent and -independent pathways. These studies indicate for the first time that the mitochondrial K-ATP channel opener diazoxide improves neurological function after spinal cord ischemia and reperfusion by diminishing levels of reactive oxygen species, decreasing DNA oxidative damage, and inhibiting caspase-dependent and -independent apoptotic pathways while preserving mitochondrial structure.

Increased mitochondrial reactive oxygen species production in newborn brain during hypoglycemia.

Hypoglycemia is associated with gray and white matter injury in immature brain, but the specific mechanisms responsible for hypoglycemic brain injury remain poorly defined. We postulated that mitochondrial electron transport chain function is altered during hypoglycemia due to the decreased availability of reducing equivalents, and that altered activity of the electron transport chain would increase mitochondrial production of free radicals and lead to mitochondrial oxidant injury. The present study tests the hypothesis that production of reactive oxygen species (ROS) by cerebral mitochondria is increased during acute hypoglycemia. Studies were performed in an awake, chronically catheterized newborn piglet model. Hypoglycemia (blood glucose 1 mmol/L for 2 h) was induced using a bolus of intravenous lispro insulin, 25 U/kg. Superoxide and hydrogen peroxide production by mitochondria isolated from cerebral cortex of normoglycemic and hypoglycemic newborn piglets was measured using lucigenin- and luminol-derived chemiluminescence. After 2 h of hypoglycemia, superoxide generation was 60% higher and hydrogen peroxide generation was two-fold higher in mitochondria from hypoglycemia animals than in controls (p < 0.005). These data confirm that the ability of the mitochondria to produce ROS is increased after hypoglycemia in immature brain, and are, to our knowledge, the first evidence that ROS may play a role in brain injury due to neonatal hypoglycemia. Increased mitochondrial ROS production could result in alterations in brain structure and function due to oxidant injury to mitochondrial proteins and DNA or changes in oxidant-sensitive signal transduction pathways in brain.

beta(2)-Adrenergic stimulation attenuates left ventricular remodeling, decreases apoptosis, and improves calcium homeostasis in a rodent model of ischemic cardiomyopathy.

The benefit of the beta(2)-adrenergic agonist, clenbuterol, in left ventricular assist device patients with dilated cardiomyopathy has been reported, but its effect on ischemic heart failure (HF) is unknown. We investigated whether clenbuterol improves left ventricular remodeling, myocardial apoptosis and has synergy with a beta(1) antagonist, metoprolol, in a model of ischemic HF. Rats were randomized to: 1) HF only; 2) HF + clenbuterol; 3) HF + metoprolol; 4) HF + clenbuterol + metoprolol; and 5) rats with sham surgery. HF was induced by left anterior descending artery (LAD) artery ligation and confirmed by decreased left ventricular fractional shortening, decreased maximum left ventricular dP/dt (dP/dt(max)), and elevated left ventricular end-diastolic pressure (LVEDP) compared with sham rats (p < 0.01). After 9 weeks of oral therapy, echocardiographic, hemodynamic, and ex vivo end-diastolic pressure-volume relationship (EDPVR) measurements were obtained. Immunohistochemistry was performed for myocardial apoptosis and DNA damage markers. Levels of calcium-handling proteins were assessed by Western blot analysis. Clenbuterol-treated HF rats had increased weight gain and heart weights versus HF rats (p < 0.05). EDPVR curves revealed a leftward shift in clenbuterol rats versus metoprolol and HF rats (p < 0.05). The metoprolol-treated group had a lower LVEDP and higher dP/dt(max) versus the HF group (p < 0.05). Clenbuterol and metoprolol groups had decreased myocardial apoptosis and DNA damage markers and increased DNA repair markers versus HF rats (all p < 0.01). Protein levels of the ryanodine receptor and sarcoplasmic reticulum calcium-ATPase were improved in clenbuterol-, metoprolol-, and clenbuterol+metoprolol-treated groups versus HF rats. However, as a combination therapy, there were no synergistic effects of clenbuterol+metoprolol treatment. We conclude that clenbuterol ameliorates EDPVR, apoptosis, and calcium homeostasis but does not have synergy with metoprolol in our model of ischemic HF.

Cardiac myocyte apoptosis is associated with increased DNA damage and decreased survival in murine models of obesity.

Disruption of leptin signaling is associated with obesity, heart failure, and cardiac hypertrophy, but the role of leptin in cardiac myocyte apoptosis is unknown. We tested the hypothesis that apoptosis increases in leptin-deficient ob/ob and leptin-resistant db/db mice and is associated with aging and left ventricular hypertrophy, increased DNA damage, and decreased survival. We studied young (2- to 3-month-old) and old (12- to 14-month-old) ob/ob and db/db mice and wild-type (WT) controls (n=2 to 4 per group). As expected, ventricular wall thickness and heart weights were similar among young ob/ob, db/db, and WT mice, but higher in old ob/ob and db/db versus old WT. Young ob/ob and db/db showed markedly elevated apoptosis by TUNEL staining and caspase 3 levels compared with WT. Differences in apoptosis were further accentuated with age. Leptin treatment significantly reduced apoptosis in ob/ob mice both in intact hearts and isolated myocytes. Tissue triglycerides were increased in ob/ob hearts, returning to WT levels after leptin repletion. Furthermore, the DNA damage marker, 8oxoG (8-oxo-7,8-dihydroguanidine), was increased, whereas the DNA repair marker, MYH glycosylase, was decreased in old ob/ob and db/db compared with old WT mice. Both ob/ob and db/db mice had decreased survival compared with WT mice. We conclude that leptin-deficient and leptin-resistant mice demonstrate increased apoptosis, DNA damage, and mortality compared with WT mice, suggesting that normal leptin signaling is necessary to prevent excess age-associated DNA damage and premature mortality. These data offer novel insights into potential mechanisms of myocardial dysfunction and early mortality in obesity.

Self-assembly peptide prevents blood loss.

Recently, researchers from the Massachusetts Institute of Technology and the University of Hong Kong discovered a new peptide that immediately stopped bleeding at the surgical site. Nanohemostat solution stops blood flow in less than 10 seconds in the cutting site of brain, spinal cord, femoral artery, and liver. Although the actual mechanism of action is not known, it is believed that the peptides are able to self-assemble into a nanofibrous scaffold network that provides these remarkable properties.