A novel angiopoietin-derived peptide displays anti-angiogenic activity and inhibits tumour-induced and retinal neovascularization

BACKGROUND AND PURPOSE

Pathological angiogenesis is associated with various human diseases, such as cancer, autoimmune diseases and retinopathy. The angiopoietin (Ang)-Tie2 system plays critical roles in several steps of angiogenic remodelling. Here, we have investigated the anti-angiogenic effect of a novel angiopoietin-derived peptide.

EXPERIMENTAL APPROACH

Using computational methods, we identified peptides from helical segments within angiopoietins, which were predicted to inhibit their activity. These peptides were tested using biochemical methods and models of angiogenesis. The peptide with best efficacy, A11, was selected for further characterization as an anti-angiogenic compound.

KEY RESULTS

The potent anti-angiogenic activity of A11 was demonstrated in a multicellular assay of angiogenesis and in the chorioallantoic membrane model. A11 bound to angiopoietins and reduced the binding of Ang-2 to Tie2. A11 was also significantly reduced vascular density in a model of tumour-induced angiogenesis. Its ability to inhibit Ang-2 but not Ang-1-induced endothelial cell migration, and to down-regulate Tie2 levels in tumour microvessels, suggests that A11 targets the Ang-Tie2 pathway. In a rat model of oxygen-induced retinopathy, A11 strongly inhibited retinal angiogenesis. Moreover, combination of A11 with an anti-VEGF antibody showed a trend for further inhibition of angiogenesis, suggesting an additive effect.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that A11 is a potent anti-angiogenic compound, through modulation of the Ang-Tie2 system, underlining its potential as a therapeutic agent for the treatment of ocular and tumour neovascularization, as well as other pathological conditions that are dependent on angiogenesis.

Follicular development and expression of nuclear respiratory factor-1 and peroxisome proliferator-activated receptor γ coactivator-1 alpha in ovaries of fetal and neonatal doelings

In livestock, the ovarian reserve of follicles is established during the fetal stage. However, at least two-thirds of the oocytes present in the reserve die because of apoptosis before birth. Notably, mitochondria have been reported to play a crucial role in the fate (life/death) of oocytes. In this study, mitochondrial regulators nuclear respiratory factor-1 (NRF-1) and PPAR γ coactivator-1 alpha (PGC-1α) were examined during this period of follicle development to investigate their effects on follicular development and apoptosis. Fetal and neonatal Capra haimen were used, ranging in age from 60 d postcoitum (dpc) to 30 d postpartum (dpp). Our data demonstrated that egg nests were the earliest recognizable gamete cells in ovaries of fetal and neonatal doelings. Proportions of egg nests decreased from 92.68 to 25.08% whereas single follicles increased from 7.32 to 74.92% between 60 and 120 dpc. Subsequently, between 90 and 120 dpc, the proportion of primordial follicles increased from 9.98 to 61.56% (P < 0.01). However, it did not change between 1 and 30 dpp (P = 0.12). The proportion of primary follicles increased from 1.23 to 37.93% between 90 dpc to 1 dpp (P = 0.01) but did not change between 1 and 30 dpp (P = 0.11). Meanwhile, proportions of secondary and tertiary follicles increased in an age-dependent manner. In addition, results of this study suggested that NRF-1 and PGC-1α proteins are mainly localized in germ cells of egg nests, cytoplasm of oocytes, and granulosa cells of follicles ranging from primordial to tertiary follicles. The transcript abundance of NRF-1 mRNA was up-regulated in 60-dpc-old ovaries compared with 1-dpp-old ovaries (P < 0.05), but the PGC-1α mRNA expression pattern did not change (P = 0.05). Nevertheless, the number of terminal deoxynucleotidyltransferase UTP nick-end labeling (TUNEL) positive cells and caspase-3 activity in 60-dpc-old ovaries was less than those in 1-dpp-old ovaries (P < 0.01, P = 0.01). In conclusion, our results demonstrate that the key stage of primordial follicle formation is between 90 and 120 dpc in Capra haimen. Also, this study suggests that NRF-1 and PGC-1α might have roles in cell apoptosis during ovarian development of fetal and neonatal Capra haimen. These results improve our understanding of apoptotic mechanisms in oogenesis and folliculogenesis.

Prevalence and risk factors of diabetic retinopathy in Chongqing pre-diabetes patients

PURPOSE

To investigate the prevalence of diabetic retinopathy (DR) and relative risk factors among Chongqing pre-diabetes patients.

METHODS

A total of 750 participants were recruited in this cross-sectional study. All participants underwent a complete physical examination and an oral glucose-tolerance test. In all, 110 of the 125 newly diagnosed pre-diabetics and their healthy spouses as controls were examined with fluorescence fundus angiographies, and their blood with biochemical analyses. All the pre-diabetics with DR (23 subjects), 23 normal controls and 23 pre-diabetics without DR were compared for serum concentrations of regulated upon activation, normal T-expressed and secreted (RANTES). Student's t-test was used to compare continuous variables, and χ (2) test and analysis of variance to compare proportions among groups. Multiple logistic regression models were used to determine the risk factors for DR in pre-diabetics.

RESULTS

In all, 20.91% of the 110 pre-diabetics showed mild non-proliferative DR (NPDR). There was a statistically significant difference in serum concentrations of RANTES between pre-diabetics with and without DR (P<0.01), and also between pre-diabetics with DR and normal controls (P<0.01). However, age, body mass index, waist-hip ratio, triacylglycerol (TG), total cholesterol (TC), high-density lipoprotein-C, low-density lipoprotein-C, blood urea nitrogen, blood creatinine, and urine albumin excretion rate seemed to have no reliable relationship with DR in pre-diabetics (P>0.05).

CONCLUSION

The prevalence of DR in Chongqing pre-diabetes patients in the study was about 20.91% and only mild NPDR was found. It seems that RANTES is one possible risk factor associated with DR in pre-diabetics, not age, TG and TC, and others.

The clinical value of in vivo confocal microscopy for diagnosis of ocular surface squamous neoplasia

PURPOSE

To determine the reliability and efficiency of in vivo confocal microscopy for the diagnosis of ocular surface squamous neoplasia (OSSN).

METHODS

A case series with five consecutive cases of OSSN were investigated retrospectively, of which the characteristics and subspecial types had been estimated by in vivo confocal microscopy before surgery. The structure and cellular features of OSSN were analyzed with other examinations, such as anterior-segment optical coherence tomography (AS-OCT), and confirmed by histopathological biopsy.

RESULTS

The tumors revealed red gelatinous surfaces with vascular dilatation on the ocular surface of the conjunctival and corneal epithelium in anterior segment photography. Involvement of only corneal epithelium was observed by AS-OCT in three cases, whereas the Bowman's layer and anterior stroma were also invaded in the other two cases. In vivo confocal microscopy showed cellular anisocytosis and enlarged nuclei with high nuclear to cytoplasmic ratio in three cases diagnosed as conjunctival intraepithelial neoplasia; moreover, nests were partially formed by isolated keratinized, binucleated, and actively mitotic dysmorphic epithelial cells in the other two cases diagnosed as carcinoma in situ and ocular surface squamous carcinoma (OSSC). The characteristics assessed from histopathological biopsy were similar to that revealed by in vivo confocal microscopy in all five cases.

CONCLUSION

In vivo confocal microscopy analysis of cytological characteristics of OSSN is a safe, relatively noninvasive, and effective diagnostic tool in detecting characteristics of OSSN before surgical resection. Although in vivo confocal microscopy cannot replace excisional biopsy for definitive diagnosis, it can be valuable for initial diagnosis and management of patients with OSSN.

Modified detector tomography technique applied to a superconducting multiphoton nanodetector

We present an experimental method to characterize multi-photon detectors with a small overall detection efficiency. We do this by separating the nonlinear action of the multiphoton detection event from linear losses in the detector. Such a characterization is a necessary step for quantum information protocols with single and multiphoton detectors and can provide quantitative information to understand the underlying physics of a given detector. This characterization is applied to a superconducting multiphoton nanodetector, consisting of an NbN nanowire with a bowtie-shaped subwavelength constriction. Depending on the bias current, this detector has regimes with single and multiphoton sensitivity. We present the first full experimental characterization of such a detector.

Tacrolimus enhances the invasion potential of hepatocellular carcinoma cells and promotes lymphatic metastasis in a rat model of hepatocellular carcinoma: involvement of vascular endothelial growth factor-C

PURPOSE

The purpose of this study was to elucidate the effect of tacrolimus treatment on tumor growth and metastasis of hepatocellular carcinoma (HCC).

METHODS

The effect of tacrolimus was investigated on tumor growth and lymph node metastasis in a rat model of HCC. Angiogenesis and lymphangiogenesis were assessed by CD31 and vascular endothelial growth factor receptor 3 (VEGFR-3) immunostaining. Cell proliferation and invasion were monitored in vitro using the Cell Counting Kit-8 (CCK8) and Matrigel Invasion Chambers, respectively. Levels of vascular endothelial growth factor-C (VEGF-C) expression were measured using quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemisty and Western blots.

RESULTS

Tacrolimus had no effect on the proliferation of HCC in vitro or in vivo. Treatment with tacrolimus resulted in a dose-dependent increase in the invasive potential of HCC cells in vitro, in the density of peritumoral lymphatic vessels, and in the number and volume of metastatic lymph nodes in August Copenhagen Irish (ACI) rats. qRT-PCR, immunohistochemisty, and Western blot revealed that tacrolimus increased the levels of expression of VEGF-C in HCC.

CONCLUSIONS

Tacrolimus enhanced the invasive potential of HCC cells, facilitating HCC lymphangiogenesis and promoting lymphatic metastasis in a rat model of HCC. This influence may be the result of an increase in VEGF-C expression by HCC cells. Targeting the VEGF-C/Fms-related tyrosine kinase 4 axis may be a novel treatment for HCC patients after liver transplantation.

Assessment of mental fatigue during car driving by using high resolution EEG activity and neurophysiologic indices

Driving tasks are vulnerable to the effects of sleep deprivation and mental fatigue, diminishing driver's ability to respond effectively to unusual or emergent situations. Physiological and brain activity analysis could help to understand how to provide useful feedback and alert signals to the drivers for avoiding car accidents. In this study we analyze the insurgence of mental fatigue or drowsiness during car driving in a simulated environment by using high resolution EEG techniques as well as neurophysiologic variables such as heart rate (HR) and eye blinks rate (EBR). Results suggest that it is possible to introduce a EEG-based cerebral workload index that it is sensitive to the mental efforts of the driver during drive tasks of different levels of difficulty. Workload index was based on the estimation of increase of EEG power spectra in the theta band over prefrontal areas and the simultaneous decrease of EEG power spectra over parietal areas in alpha band during difficult drive conditions. Such index could be used in a future to assess on-line the mental state of the driver during the drive task.

Therapeutic Effects of Ethyl Pyruvate on Tumor Growth and Metastasis in a Severe Combined Immunodeficiency Mouse Orthotopic Implantation Model

Ethyl pyruvate (EP) has been shown to have significant anti-inflammatory activities. Here, we explore the therapeutic effects of EP administration on tumor growth and metastasis in orthotopic implantation human gastric cancer models in severe combined immunodeficiency (SCID) mice. After SCID mice were treated with EP, the tumor growth and liver metastasis from gastric cancer were investigated and its possible molecular mechanisms were further studied. As a result, it was found that EP could inhibit tumor growth and liver metastasis of gastric cancer, and reduce tumor lymphangiogenesis indicated by lymphatic microvessel density (LVD) in gastric cancer and metastatic liver tumor. Also, EP decreased the expression of high mobility group box-B1 (HMGB1), receptor for advanced glycation endproducts (RAGE), vascular endothelial growth factor (VEGF) and membrane type-1 matrix metalloprotease (MT1-MMP) in gastric cancer and metastatic liver tumor, but it exerted no effect on expression of nuclear factor-kappa B (NF-κB). Taken together, we suggest that the new application of EP could be a therapeutic option in the treatment of gastric cancer and metastatic liver tumor.

Comparison of cryopreservation methods on T-cell responses to islet and control antigens from type 1 diabetic patients and controls

BACKGROUND

Type 1 diabetes (T1D) is a cell-mediated autoimmune disease characterized by destruction of the pancreatic islet cells. The use of cryopreserved cells is preferable to the use of freshly isolated cells to monitor clinical trials to decrease assay and laboratory variability.

METHODS

The T-Cell Workshop Committee of the Immunology of Diabetes Society compared two widely accepted T-cell freezing protocols (warm and cold) to freshly isolated peripheral blood mononuclear cells from patients with T1D and controls in terms of recovery, viability, cell subset composition, and performance in functional assays currently in use in T1D-related research. Nine laboratories participated in the study with four different functional assays included.

RESULTS

The cold freezing method yielded higher recovery and viability compared with the warm freezing method. Irrespective of freezing protocol, B cells and CD8+ T cells were enriched, monocyte fraction decreased, and islet antigen-reactive responses were lower in frozen versus fresh cells. However, these results need to take in to account that the overall response to islet autoantigens was low in some assays.

CONCLUSIONS

In the current study, none of the tested T-cell functional assays performed well using frozen samples. More research is required to identify a freezing method and a T-cell functional assay that will produce responses in patients with T1D comparable to responses using fresh peripheral blood mononuclear cells.