Relationships between Body Fat Distribution,Epicardial Fat and Obstructive Sleep Apnea in Obese Patients with and without Metabolic Syndrome

Background

Obstructive sleep apnea (OSA) and metabolic syndrome, both closely related to obesity, often coexist in affected individuals; however, body mass index is not an accurate indicator of body fat and thus is not a good predictor of OSA and other comorbidities. The aim of this study was to investigate whether the occurrence of OSA could be associated with an altered body fat distribution and a more evident cardio metabolic risk independently from obesity and metabolic syndrome.

Methods and Results

171 consecutive patients (58 men and 113 women) were included in the study and underwent overnight polysomnography. Anthropometric data, blood pressure, lipid profile, glycaemic parameters were recorded. Body composition by DXA, two-dimensional echocardiography and carotid intima/media thickness measurement were performed. 67 patients (39.2%) had no OSA and 104 (60.8%) had OSA. The percentage of patients with metabolic syndrome was significantly higher among OSA patients (65.4%) that were older, heavier and showed a bigger and fatter heart compared to the control group. Upper body fat deposition index , the ratio between upper body fat (head, arms and trunk fat in kilograms) and lower body fat (legs fat in kilograms), was significantly increased in the OSA patients and significantly related to epicardial fat thickness. In patients with metabolic syndrome, multivariate regression analyses showed that upper body fat deposition index and epicardial fat showed the best association with OSA.

Conclusion

The occurrence of OSA in obese people is more closely related to cardiac adiposity and to abnormal fat distribution rather than to the absolute amount of adipose tissue. In patients with metabolic syndrome the severity of OSA is associated with increase in left ventricular mass and carotid intima/media thickness.     

Functional analysis of the group A streptococcal luxS/AI-2 system in metabolism, adaptation to stress and interaction with host cells

Background

The luxS/AI-2 signaling pathway has been reported to interfere with important physiological and pathogenic functions in a variety of bacteria. In the present study, we investigated the functional role of the streptococcal luxS/AI-2 system in metabolism and diverse aspects of pathogenicity including the adaptation of the organism to stress conditions using two serotypes of Streptococcus pyogenes, M1 and M19.

Results

Exposing wild-type and isogenic luxS-deficient strains to sulfur-limited media suggested a limited role for luxS in streptococcal activated methyl cycle metabolism. Interestingly, loss of luxS led to an increased acid tolerance in both serotypes. Accordingly, luxS expression and AI-2 production were reduced at lower pH, thus linking the luxS/AI-2 system to stress adaptation in S. pyogenes. luxS expression and AI-2 production also decreased when cells were grown in RPMI medium supplemented with 10% serum, considered to be a host environment-mimicking medium. Furthermore, interaction analysis with epithelial cells and macrophages showed a clear advantage of the luxS-deficient mutants to be internalized and survive intracellularly in the host cells compared to the wild-type parents. In addition, our data revealed that luxS influences the expression of two virulence-associated factors, the fasX regulatory RNA and the virulence gene sibA (psp).

Conclusion

Here, we suggest that the group A streptococcal luxS/AI-2 system is not only involved in the regulation of virulence factor expression but in addition low level of luxS expression seems to provide an advantage for bacterial survival in conditions that can be encountered during infections.     

Comparable Long-Term Efficacy of Lopinavir/Ritonavir and Similar Drug-Resistance Profiles in Different HIV-1 Subtypes

Background

Analysis of potentially different impact of Lopinavir/Ritonavir (LPV/r) on non-B subtypes is confounded by dissimilarities in the conditions existing in different countries. We retrospectively compared its impact on populations infected with subtypes B and C in Israel, where patients infected with different subtypes receive the same treatment.

Methods

Clinical and demographic data were reported by physicians. Resistance was tested after treatment failure. Statistical analyses were conducted using SPSS.

Results

607 LPV/r treated patients (365 male) were included. 139 had HIV subtype B, 391 C, and 77 other subtypes. At study end 429 (71%) were receiving LPV/r. No significant differences in PI treatment history and in median viral-load (VL) at treatment initiation and termination existed between subtypes. MSM discontinued LPV/r more often than others even when the virologic outcome was good (p = 0.001). VL was below detection level in 81% of patients for whom LPV/r was first PI and in 67% when it was second (P = 0.001). Median VL decrease from baseline was 1.9±0.1 logs and was not significantly associated with subtype. Median CD4 increase was: 162 and 92cells/µl, respectively, for patients receiving LPV/r as first and second PI (P = 0.001), and 175 and 98, respectively, for subtypes B and C (P<0.001). Only 52 (22%) of 237 patients genotyped while under LPV/r were fully resistant to the drug; 12(5%) were partially resistant. In48%, population sequencing did not reveal resistance to any drug notwithstanding the virologic failure. No difference was found in the rates of resistance development between B and C (p = 0.16).

Conclusions

Treatment with LPV/r appeared efficient and tolerable in both subtypes, B and C, but CD4 recovery was significantly better in virologically suppressed subtype-B patients. In both subtypes, LPV/r was more beneficial when given as first PI. Mostly, reasons other than resistance development caused discontinuation of treatment.     

Immediate Effects of Experimental Human Trampling on Mid-Upper Intertidal benthic Invertebrates at the Asinara Island MPA (NW Mediterranean)

To assess potential risks of human visitation to ecological communities, the immediate effects of human trampling were investigated experimentally on small invertebrates inhabiting mid-upper intertidal hard bottoms covered by algae. Two different experimental intensities of trampling (60 and 120 footsteps) and controls (with no trampling) were applied to quadrats 20×20 cm in size (experimental area), within the two ‘no-entry, no-take’ zones of the Asinara Island MPA (Italy, Mediterranean Sea). One day after trampling ended, samples of benthic fauna were collected and the animals attributed to macrofaunal and meiofaunal components. Analyses of variance on the nine most common taxa of macrofauna identified significant higher abundance of bivalves, gammarid amphipods, polychaetes, isopods, oligochaetes in controls than in trampled plots. For nematodes, polychaetes, ostracods, oligochaetes, bivalves, acari, caprellid amphipods and tanaids a significant higher abundance of meiofaunal animals was found in controls than in trampled areas. Although no information on recovery is available, these results suggest that macrofaunal and meiofaunal taxa are vulnerable to this type of disturbance.     

Kinetics and frequency of adeno-associated virus site-specific integration into human chromosome 19 monitored by quantitative real-time PCR

Adeno-associated virus type 2 (AAV-2) integrates specifically into a site on human chromosome 19 (chr-19) called AAVS1. To study the kinetics and frequency of chr-19-specific integration after AAV infection, we developed a rapid, sensitive, and quantitative real-time PCR assay for AAV inverted terminal repeat-chr-19-specific junctions. Despite the known variability of junction sites, conditions were established that ensured reliable quantification of integration rates within hours after AAV infection. The overall integration frequency was calculated to peak at between 10 and 20% of AAV-infected, unselected HeLa cells. At least 1 in 1,000 infectious AAV-2 particles was found to integrate site specifically up to day 4 postinfection in the absence of selection. Chromosomal breakpoints within AAVS1 agreed with those found in latently infected clonal cell lines and transgenic animals. Use of this quantitative real-time PCR will greatly facilitate the study of the early steps of wild-type and recombinant AAV vector integration.     

Effects of simulated microgravity on thyroid carcinoma cells

We aimed to investigate whether simulated microgravity on thyroid carcinoma cells could help to perform in vitro cancer studies such as antitumor drug tests more reliable and to spare animal experiments. We cultured cancer cells at 0 g to enable formation of three-dimensional multicellular tumor spheroids (MCTS), which will resemble the originating tumors. Under microgravity human follicular cells (ML-1 cell line) keep floating with-out stirring so that initial cell-cell interactions required for spheroid formation will be induced by forces due to biochemical components actually expressed on surfaces of cells, whereas gravity related push- or shear events will not influence MCTS formation. Within 12 hours of clinorotation the monolayer turned spontaneously into MCTS with remarkable features: An increase of extracellular matrix proteins and TGF-beta 1. Thyroglobulin, ft3 and ft4 secretion were markedly reduced. These data are in agreement with the observation that astronauts show low thyroid hormone levels after spaceflight.     

Histone hyperacetylation in mitosis prevents sister chromatid separation and produces chromosome segregation defects

Posttranslational modifications of core histones contribute to driving changes in chromatin conformation and compaction. Herein, we investigated the role of histone deacetylation on the mitotic process by inhibiting histone deacetylases shortly before mitosis in human primary fibroblasts. Cells entering mitosis with hyperacetylated histones displayed altered chromatin conformation associated with decreased reactivity to the anti-Ser 10 phospho H3 antibody, increased recruitment of protein phosphatase 1-delta on mitotic chromosomes, and depletion of heterochromatin protein 1 from the centromeric heterochromatin. Inhibition of histone deacetylation before mitosis produced defective chromosome condensation and impaired mitotic progression in living cells, suggesting that improper chromosome condensation may induce mitotic checkpoint activation. In situ hybridization analysis on anaphase cells demonstrated the presence of chromatin bridges, which were caused by persisting cohesion along sister chromatid arms after centromere separation. Thus, the presence of hyperacetylated chromatin during mitosis impairs proper chromosome condensation during the pre-anaphase stages, resulting in poor sister chromatid resolution. Lagging chromosomes consisting of single or paired sisters were also induced by the presence of hyperacetylated histones, indicating that the less constrained centromeric organization associated with heterochromatin protein 1 depletion may promote the attachment of kinetochores to microtubules coming from both poles.