Liver steatosis coexists with myocardial insulin resistance and coronary dysfunction in patients with type 2 diabetes

Nonalcoholic fatty liver (NAFL) is a common comorbidity in patients with type 2 diabetes and links to the risk of coronary syndromes. The aim was to determine the manifestations of metabolic syndrome in different organs in patients with liver steatosis. We studied 55 type 2 diabetic patients with coronary artery disease using positron emission tomography. Myocardial perfusion was measured with [15O]H2O and myocardial and skeletal muscle glucose uptake with 2-deoxy-2-[18F]fluoro-D-glucose during hyperinsulinemic euglycemia. Liver fat content was determined by magnetic resonance proton spectroscopy. Patients were divided on the basis of their median (8%) into two groups with low (4.6 +/- 2.0%) and high (17.4 +/- 8.0%) liver fat content. The groups were well matched for age, BMI, and fasting plasma glucose. In addition to insulin resistance at the whole body level (P = 0.012) and muscle (P = 0.002), the high liver fat group had lower insulin-stimulated myocardial glucose uptake (P = 0.040) and glucose extraction rate (P = 0.0006) compared with the low liver fat group. In multiple regression analysis, liver fat content was the most significant explanatory variable for myocardial insulin resistance. In addition, the high liver fat group had increased concentrations of high sensitivity C-reactive protein, soluble forms of E-selectin, vascular adhesion protein-1, and intercellular adhesion molecule-1 (P < 0.05) and lower coronary flow reserve (P = 0.02) compared with the low liver fat group. In conclusion, in patients with type 2 diabetes and coronary artery disease, liver fat content is a novel independent indicator of myocardial insulin resistance and reduced coronary functional capacity. Further studies will reveal the effect of hepatic fat reduction on myocardial metabolism and coronary function.     

Contamination routes of Clostridium botulinum in the honey production environment

Factors influencing Clostridium botulinum contamination in the honey production environment were evaluated in a 3-year survey. A number of 1,168 samples from 100 apiaries and related facilities were analysed for the presence of C. botulinum types A, B, E and F, using multiplex polymerase chain reaction targeted to botA, botB, botE and botF genes. Production methods and environmental factors were registered using a questionnaire and by personal observation. Clostridium botulinum was shown to be a common finding throughout the whole honey production chain, and the type most frequently detected was group I type B. In a pulsed-field gel electrophoresis (PFGE) analysis of 202 group I type B isolates, only six different PFGE profiles were observed, of which two clearly distinct profiles predominated. This may indicate the existence of at least two different genetic lineages. The high prevalence of C. botulinum in soil and in samples associated with beeswax suggests the accumulation of soil-derived botulinal spores in wax. Additionally, according to Spearman's rank order correlation and multivariate analysis, production hygiene-dependent factors have a significant influence on the contamination, and thus the number and frequency of C. botulinum spores in honey could possibly be diminished by increasing hygienic level in honey production.     

A Defined and Xeno-Free Culture Method Enabling the Establishment of Clinical-Grade Human Embryonic,Induced Pluripotent and Adipose Stem Cells

Background

The growth of stem cells in in vitro conditions requires optimal balance between signals mediating cell survival, proliferation, and self-renewal. For clinical application of stem cells, the use of completely defined conditions and elimination of all animal-derived materials from the establishment, culture, and differentiation processes is desirable.

Methodology/Principal Findings

Here, we report the development of a fully defined xeno-free medium (RegES), capable of supporting the expansion of human embryonic stem cells (hESC), induced pluripotent stem cells (iPSC) and adipose stem cells (ASC). We describe the use of the xeno-free medium in the derivation and long-term (>80 passages) culture of three pluripotent karyotypically normal hESC lines: Regea 06/015, Regea 07/046, and Regea 08/013. Cardiomyocytes and neural cells differentiated from these cells exhibit features characteristic to these cell types. The same formulation of the xeno-free medium is capable of supporting the undifferentiated growth of iPSCs on human feeder cells. The characteristics of the pluripotent hESC and iPSC lines are comparable to lines derived and cultured in standard undefined culture conditions. In the culture of ASCs, the xeno-free medium provided significantly higher proliferation rates than ASCs cultured in medium containing allogeneic human serum (HS), while maintaining the differentiation potential and characteristic surface marker expression profile of ASCs, although significant differences in the surface marker expression of ASCs cultured in HS and RegES media were revealed.

Conclusion/Significance

Our results demonstrate that human ESCs, iPSCs and ASCs can be maintained in the same defined xeno-free medium formulation for a prolonged period of time while maintaining their characteristics, demonstrating the applicability of the simplified xeno-free medium formulation for the production of clinical-grade stem cells. The basic xeno-free formulation described herein has the potential to be further optimized for specific applications relating to establishment, expansion and differentiation of various stem cell types.     

Early Life Origins Cognitive Decline: Findings in Elderly Men in the Helsinki Birth Cohort Study

Objectives

To examine whether the adverse effects of slow prenatal and postnatal growth on cognitive function persist to old age and predict age related cognitive decline.

Design and Setting

A longitudinal birth cohort study of men born in Helsinki, Finland 1934-44.

Participants

Nine-hundred-thirty-one men of the Helsinki Birth Cohort Study, with detailed data on growth from birth to adulthood, aged 20.1 (SD = 1.4) at the first and 67.9 (SD = 2.5) years at the second cognitive testing.

Main Outcome Measures

The Finnish Defense Forces Basic Intellectual Ability Test assessed twice over nearly five decades apart.

Results

Lower weight, length and head circumference at birth were associated with lower cognitive ability at 67.9 years (1.04–1.55 points lower ability per each standard deviation [SD] unit decrease in body size, 95% Confidence Interval [95%CI]: 0.05 to 2.72) and with cognitive decline after 20.1 years (0.07–0.11 SD decline over time per each SD decrease in body size, 95%CI:0.00 to 0.19). Men who were born larger were more likely to perform better in the cognitive ability test over time (1.22–1.43 increase in odds to remain in the top relative to the lower two thirds in ability over time per each SD increase in body size, 95%CI:1.04 to 1.79) and were more resilient to cognitive decline after 20.1 years (0.69 to 0.76 decrease in odds to decline from than remain in the top third of ability over time per each SD increase in body size, 95%CI:0.49 to 0.99). Slower growth between birth and two years in weight, height and body mass index was associated with lower cognitive ability at 67.9 years, but not with cognitive decline.

Conclusions

Poorer lifetime cognitive ability is predicted by slower growth before and after birth. In predicting resilience to age related cognitive decline, the period before birth seems to be more critical.     

Application of Denaturing High-Performance Liquid Chromatography for Monitoring Sulfate-Reducing Bacteria in Oil Fields

Sulfate-reducing bacteria (SRB) participate in microbially induced corrosion (MIC) of equipment and H₂S-driven reservoir souring in oil field sites. Successful management of industrial processes requires methods that allow robust monitoring of microbial communities. This study investigated the applicability of denaturing high-performance liquid chromatography (DHPLC) targeting the dissimilatory sulfite reductase ß-subunit (dsrB) gene for monitoring SRB communities in oil field samples from the North Sea, the United States, and Brazil. Fifteen of the 28 screened samples gave a positive result in real-time PCR assays, containing 9 × 10¹ to 6 × 10⁵ dsrB gene copies ml⁻¹. DHPLC and denaturing gradient gel electrophoresis (DGGE) community profiles of the PCR-positive samples shared an overall similarity; both methods revealed the same samples to have the lowest and highest diversity. The SRB communities were diverse, and different dsrB compositions were detected at different geographical locations. The identified dsrB gene sequences belonged to several phylogenetic groups, such as Desulfovibrio, Desulfococcus, Desulfomicrobium, Desulfobulbus, Desulfotignum, Desulfonatronovibrio, and Desulfonauticus. DHPLC showed an advantage over DGGE in that the community profiles were very reproducible from run to run, and the resolved gene fragments could be collected using an automated fraction collector and sequenced without a further purification step. DGGE, on the other hand, included casting of gradient gels, and several rounds of rerunning, excising, and reamplification of bands were needed for successful sequencing. In summary, DHPLC proved to be a suitable tool for routine monitoring of the diversity of SRB communities in oil field samples.     

Tumor necrosis factor alpha promotes the expression of immunosuppressive proteins and enhances the cell growth in a human bone marrow-derived stem cell culture

Mesenchymal stem cells (MSCs) are widely used in experimental treatments for various conditions that involve normal tissue regeneration via inflammatory repair. It is known that MSCs can secrete multiple soluble factors and suppress inflammation. Even though the effect of MSCs on inflammation has been extensively studied, the effect of inflammation on MSCs is poorly understood. One of the major cytokines released at the site of inflammation is tumor necrosis factor alpha (TNF-α) which is known to induce MSC invasion and proliferation. Therefore, we wanted to test the effects of TNF-α exposure on MSCs derived from human bone marrow. We found, as expected, that cell proliferation was significantly enhanced during TNF-α exposure. However, according to the cell surface marker analysis, the intensity of several antigens in the minimum criteria panel for MSCs proposed by International Society of Cellular Therapy (ISCT) was decreased dramatically, and in certain cases, the criteria for MSCs were not fulfilled. In addition, TNF-α exposure resulted in a significant but transient increase in human leukocyte antigen and CD54 expression. Additional proteomic analysis by two-dimensional difference gel electrophoresis and mass spectrometry revealed three proteins whose expression levels decreased and 8 proteins whose expression levels increased significantly during TNF-α exposure. The majority of these proteins could be linked to immunosuppressive and signalling pathways. These results strongly support reactive and immunosuppressive activation of MSCs during TNF-α exposure, which might influence MSC differentiation stage and capacity.     

The impact of simulated moose densities on conifer aphids along a productivity gradient

Large herbivores have a significant impact on boreal forest ecosystems. The modification of resources through their feeding induces changes in trophic dynamics and affects the direction of interactions in a community. Moose Alces alces may decrease the available plant biomass for herbivorous insects on one of their main winter forage species in Fennoscandia, Scots pine Pinus sylvestris, and indirectly alter the abundance of invertebrates through exploitative competition. Moose browsing can also induce chemical, morphological, and phenological changes in plants, changing their nutritive value to insect herbivores such as aphids. Habitat productivity may further modify the responses of aphids to moose browsing. We studied the responses of the gray pine aphid Schizolachnus pineti to different moose densities, and their relations to habitat productivity by sampling pine branches and measuring the number of aphids on pine needles. The experimental setup consisted of 8 exclosures along a productivity gradient, where the feeding, defecation, and urination of 4 densities of moose had been simulated for 7 yr. We here show that high levels of simulated browsing decrease the amount of gray pine aphids in areas with high productivity. In areas with low productivity, however, simulated browsing had no such effect. Habitat productivity should therefore be considered as an important factor that may determine the strength of an areas buffering capacity to high moose densities. Low resource environments appear to be favourable to specialist conifer aphids on pines under high browsing pressure, but the performance of generalist insect herbivores might be lowered.     

Effects of Xylitol on Xylitol-Sensitive Versus Xylitol-Resistant Streptococcus mutans Strains in a Three-Species in Vitro Biofilm

We studied the effects of xylitol on biofilms containing xylitol-resistant (Xr) and xylitol-sensitive (Xs) Streptococcus mutans, Actinomyces naeslundii and S. sanguinis. The biofilms were grown for 8 and 24 h on hydroxyapatite discs. The viable microorganisms were determined by plate culturing techniques and fluorescence in situ hybridization (FISH) was performed using a S. mutans-specific probe. Extracellular cell-bound polysaccharides (EPS) were determined by spectrofluorometry from single-species S. mutans biofilms. In the presence of 5 % xylitol, the counts of the Xs S. mutans decreased tenfold in the young (8 h) biofilm (p < 0.05) but no effect was seen in the mature (24 h) biofilm. No decrease was observed for the Xr strains, and FISH confirmed these results. No differences were detected in the EPS production of the Xs S. mutans grown with or without xylitol, nor between Xr and Xs S. mutans strains. Thus, it seems that xylitol did not affect the EPS synthesis of the S. mutans strains. Since the Xr S. mutans strains, not inhibited by xylitol, showed no xylitol-induced decrease in the biofilms, we conclude that growth inhibition could be responsible for the decrease of the counts of the Xs S. mutans strains in the clinically relevant young biofilms.