Proteasome activation as a novel antiaging strategy

Homeostasis is a key feature of cellular lifespan. Maintenance of cellular homeostasis influences the rate of aging and is determined by several factors, including efficient proteolysis of damaged proteins. Protein degradation is predominantly catalyzed by the proteasome. Specifically, the proteasome is responsible for cell clearance of abnormal, denatured or in general damaged proteins as well as for the regulated degradation of short-lived proteins. As proteasome has an impaired function during aging, emphasis has been given recently in identifying ways of its activation. A number of studies have shown that the proteasome can be activated by genetic manipulations as well as by factors that affect its conformation and stability. Importantly the developed proteasome activated cell lines exhibit an extended lifespan. This review article discusses in details the various factors that are involved in proteasome biosynthesis and assembly and how they contribute to its activation. Finally as few natural compounds have been identified having proteasome activation properties, we discuss the advantages of this novel antiaging strategy.     

Design and synthesis of nitrate esters of aromatic heterocyclic compounds as pharmacological preconditioning agents

Ischemic preconditioning (IPC) constitutes an endogenous protective mechanism in which one or more brief periods of myocardial ischemia and reperfusion render the myocardium resistant to a subsequent more-sustained ischemic insult. Pharmacological preconditioning represents an ideal alternative of IPC. We now describe the design and synthesis of indole, quinoline, and purine systems with an attached pharmacophoric nitrate ester group. The indole and quinoline derivatives 4 and 5 possess structural features of the nitrate containing K(ATP) channel openers. Purine analogues 11 and 12, substituted at the position 6 by a piperidine moiety and at position 9 by an alkyl nitrate, could combine the effects of the nitrate containing K(ATP) channel openers and those of adenosine. Compound 13 bears the nicotinamide moiety of nicorandil instead of nitrate ester. Compounds 4, 5, and 11 reduced infarction and the levels of malondialdehyde (MDA) at reperfusion in anesthetized rabbits. Compounds 12 and 13 did not significantly reduce the infarct size. Analogues 4 and 5 increased cGMP and MDA during ischemia, while combined analogue 4 and mitoK(ATP) blocker 5-hydroxydecanoic acid (5-HD) abrogated this benefit suggesting an action through mitoK(ATP) channel opening. Treatment with derivative 11 combined with 5-HD as well as treatment with 11 and adenosine receptor blocker 8-(p-sulfophenyl)theophylline (SPT) did not abrogate cardioprotection. Compound 11 is a lead molecule for the synthesis of novel analogues possessing a dual mode of action through cGMP-mitoK(ATP) channel opening-free radicals and through adenosine receptors.     

Is there any potential link among caspase-8, p-p38 MAPK and bcl-2 in clear cell renal cell carcinomas? A comparative immunohistochemical analysis with clinical connotations

Background

Management of endometrial precancerous lesions has been of much debate due to inconsistencies in their classification, natural history and histologic diagnosis. Endometrial hyperplasia constitutes a wide range of histomorphologic features associated with high intra and interobserver diagnostic variability. Although traditional microscopic diagnosis is by far the most applicable method and the gold standard for histomorphologic diagnosis, digitized image analysis has been used as a powerful adjunct to maximize the histologic data retrieval and to add some detailed objective criteria for correct diagnosis in difficult cases.

Methods

A series of 100 endometrial curettage specimens with diagnosis of endometrial hyperplasia or well differentiated adenocarcinoma were blindly reviewed by 5 pathologists; their intra and interobserver reproducibility determined and further compared to the objective morphometric data i.e. D-score and volume percent of stroma (VPS).

Results

The results were assessed using the weighted kappa statistics. Mean intraobserver kappa value was 0.8690 (99.44% agreement). Mean interobserver kappa values by diagnostic category were: simple hyperplasia without atypia: 0.7441; complex hyperplasia without atypia: 0.3379; atypical hyperplasia: 0.3473, and well-differentiated endometrioid carcinoma: 0.6428; with a kappa value of 0.5372 for all cases combined. Interobserver agreement was in substantial rate for simple hyperplasia (SH) and well differentiated adenocarcinoma (WDA) but was in fair limit for complex hyperplasia (CH) and atypical hyperplasia (AH). Intraobserver agreement was almost perfect. The specimens were divided in two groups according to the computerized morphometric analysis: Endometrial Hyperplasia (EH) ( D Score ≥ 1 or VPS ≥ 55%) and Endometrial Intraepithelial Neoplasia (EIN) (D-Score < 1 or VPS < 55%). Morphometric findings were closely compatible with routine WHO classification made by one expert pathologist; however; diagnosis of (CH) and (AH) made by other pathologists were not concordant with morphometric data.

Conclusion

It may be necessary to make some revisions in WHO classification for endometrial hyperplasia and precancerous lesions.     

Tumor Vascular Permeability to a Nanoprobe Correlates to Tumor-Specific Expression Levels of Angiogenic Markers

Background

Vascular endothelial growth factor (VEGF) receptor-2 is the major mediator of the mitogenic, angiogenic, and vascular hyperpermeability effects of VEGF on breast tumors. Overexpression of VEGF and VEGF receptor-2 is associated with the degree of pathomorphosis of the tumor tissue and unfavorable prognosis. In this study, we demonstrate that non-invasive quantification of the degree of tumor vascular permeability to a nanoprobe correlates with the VEGF and its receptor levels and tumor growth.

Methodology/Principal Findings

We designed an imaging nanoprobe and a methodology to detect the intratumoral deposition of a 100 nm-scale nanoprobe using mammography allowing measurement of the tumor vascular permeability in a rat MAT B III breast tumor model. The tumor vascular permeability varied widely among the animals. Notably, the VEGF and VEGF receptor-2 gene expression of the tumors as measured by qRT-PCR displayed a strong correlation to the imaging-based measurements of vascular permeability to the 100 nm-scale nanoprobe. This is in good agreement with the fact that tumors with high angiogenic activity are expected to have more permeable blood vessels resulting in high intratumoral deposition of a nanoscale agent. In addition, we show that higher intratumoral deposition of the nanoprobe as imaged with mammography correlated to a faster tumor growth rate. This data suggest that vascular permeability scales to the tumor growth and that tumor vascular permeability can be a measure of underlying VEGF and VEGF receptor-2 expression in individual tumors.

Conclusions/Significance

This is the first demonstration, to our knowledge, that quantitative imaging of tumor vascular permeability to a nanoprobe represents a form of a surrogate, functional biomarker of underlying molecular markers of angiogenesis.     

Carbon dioxide balneotherapy and cardiovascular disease

Carbon dioxide (CO(2)) balneotherapy is a kind of remedy with a wide spectrum of applications which have been used since the Middle Ages. However, its potential use as an adjuvant therapeutic option in patients with cardiovascular disease is not yet fully clarified. We performed a thorough review of MEDLINE Database, EMBASE, ISI WEB of Knowledge, COCHRANE database and sites funded by balneotherapy centers across Europe in order to recognize relevant studies and aggregate evidence supporting the use of CO(2) baths in various cardiovascular diseases. The three main effects of CO(2) hydrotherapy during whole body or partial immersion, including decline in core temperature, an increase in cutaneous blood flow, and an elevation of the score on thermal sensation, are analyzed on a pathophysiology basis. Additionally, the indications and contra-indications of the method are presented in an evidence-based way, while the need for new methodologically sufficient studies examining the use of CO(2) baths in other cardiovascular substrates is discussed.     

Hematocrit,viscosity and velocity distributions of aggregating and non-aggregating blood in a bifurcating microchannel

Microscale blood flow is characterised by heterogeneous distributions of hematocrit, viscosity and velocity. In microvascular bifurcations, cells are unevenly distributed between the branches, and this effect can be amplified in subsequent branches depending on a number of parameters. We propose an approach to infer hematocrit profiles of human blood flowing through a bifurcating microchannel. The influence of aggregation, induced by the addition of Dextran 2000 to the samples, is also considered. Averaged values indicate plasma skimming, particularly in the presence of red blood cell (RBC) aggregation. Using an empirical model, the hematocrit profiles are used to estimate local relative viscosity distributions. Simulations are used to predict how the non-uniform viscosity influences the velocity profiles. Comparing these data to velocity profiles of RBCs measured using particle image velocimetry provides validation of the model. It is observed that aggregation blunts velocity profiles after a long straight section of channel. Downstream of the bifurcation, skewing of the velocity profiles is detected, which is enhanced by aggregation. The proposed methodology is capable of providing hitherto unreported information on important aspects of microscale blood rheology.     

Proteasome response to interferon-gamma is altered in senescent human fibroblasts

We have investigated immunoproteasomes in human fibroblasts during replicative senescence. Unlike levels of constitutive proteasome catalytic subunits and 26S proteasome regulatory subunits, levels of immunosubunits did not decrease dramatically in senescent cells. However, the induction of immunosubunits by interferon-gamma (IFN-gamma) was lost in senescent cells. In contrast, levels of the 11S proteasome regulator, PA28, were increased by IFN-gamma even in senescent cells, and both immunosubunits and PA28 increased with the reversible growth arrest in confluent cell cultures. The results highlight differences in the mechanisms of regulation of immunoproteasomes compared to constitutive proteasomes and in the irreversible growth arrest of senescent cells compared to reversible contact-induced growth arrest.     

The effect of Debina grapevine indigenous yeast strains of <Emphasis Type="Italic">Metschnikowia</Emphasis> and <Emphasis Type="Italic">Saccharomyces</Emphasis> on wine flavour

The spontaneous alcoholic fermentation of grape must is a complex microbiological process involving a large number of various yeast species, to which the flavour of every traditional wine is largely attributed. Whilst Saccharomyces cerevisiae is primarily responsible for the conversion of sugar to alcohol, the activities of various non-Saccharomyces species enhance wine flavour. In this study, indigenous yeast strains belonging to Metschnikowia pulcherrima var. zitsae as well as Saccharomyces cerevisiae were isolated and characterized from Debina must (Zitsa, Epirus, Greece). In addition, these strains were examined for their effect on the outcome of the wine fermentation process when used sequentially as starter cultures. The resulting wine, as analyzed over three consecutive years, was observed to possess a richer, more aromatic bouquet than wine from a commercial starter culture. These results emphasize the potential of employing indigenous yeast strains for the production of traditional wines with improved flavour.