Adiponectin is inversely associated with intramyocellular and intrahepatic lipids in obese premenopausal women

Adiponectin, an adipokine secreted by adipocytes, exerts beneficial effects on glucose and lipid metabolism and has been found to improve insulin resistance by decreasing triglyceride content in muscle and liver in obese mice. Adiponectin is found in several isoforms and the high-molecular weight (HMW) form has been linked most strongly to the insulin-sensitizing effects. Fat content in skeletal muscle (intramyocellular lipids, IMCL) and liver (intrahepatic lipids, IHL) can be quantified noninvasively using proton magnetic resonance spectroscopy ((1)H-MRS). The purpose of our study was to assess the relationship between HMW adiponectin and measures of glucose homeostasis, IMCL and IHL, and to determine predictors of adiponectin levels. We studied 66 premenopausal women (mean BMI 31.0 ± 6.6 kg/m(2)) who underwent (1)H-MRS of calf muscles and liver for IMCL and IHL, computed tomography (CT) of the abdomen for abdominal fat depots, dual-energy X-ray absorptiometry (DXA) for fat and lean mass assessments, HMW and total adiponectin, fasting lipid profile and an oral glucose tolerance test (homeostasis model assessment of insulin resistance (HOMA(IR)), glucose and insulin area under the curve). There were strong inverse associations between HMW adiponectin and measures of insulin resistance, IMCL and IHL, independent of visceral adipose tissue (VAT) and total body fat. IHL was the strongest predictor of adiponectin and adiponectin was a predictor of HOMA(IR). Our study showed that in premenopausal obese women HMW adiponectin is inversely associated with IMCL and IHL content. This suggests that adiponectin exerts positive effects on insulin sensitivity in obesity by decreasing intracellular triglyceride content in skeletal muscle and liver; it is also possible that our results reflect effects of insulin on adiponectin.     

Validation and application of a PCR primer set to quantify fungal communities in the soil environment by real-time quantitative PCR

Fungi constitute an important group in soil biological diversity and functioning. However, characterization and knowledge of fungal communities is hampered because few primer sets are available to quantify fungal abundance by real-time quantitative PCR (real-time Q-PCR). The aim in this study was to quantify fungal abundance in soils by incorporating, into a real-time Q-PCR using the SYBRGreen® method, a primer set already used to study the genetic structure of soil fungal communities. To satisfy the real-time Q-PCR requirements to enhance the accuracy and reproducibility of the detection technique, this study focused on the 18S rRNA gene conserved regions. These regions are little affected by length polymorphism and may provide sufficiently small targets, a crucial criterion for enhancing accuracy and reproducibility of the detection technique. An in silico analysis of 33 primer sets targeting the 18S rRNA gene was performed to select the primer set with the best potential for real-time Q-PCR: short amplicon length; good fungal specificity and coverage. The best consensus between specificity, coverage and amplicon length among the 33 sets tested was the primer set FR1 / FF390. This in silico analysis of the specificity of FR1 / FF390 also provided additional information to the previously published analysis on this primer set. The specificity of the primer set FR1 / FF390 for Fungi was validated in vitro by cloning - sequencing the amplicons obtained from a real time Q-PCR assay performed on five independent soil samples. This assay was also used to evaluate the sensitivity and reproducibility of the method. Finally, fungal abundance in samples from 24 soils with contrasting physico-chemical and environmental characteristics was examined and ranked to determine the importance of soil texture, organic carbon content, C∶N ratio and land use in determining fungal abundance in soils.     

Allelic frequency and genotypes of prion protein at codon 136 and 171 in Iranian Ghezel sheep breeds

PrP genotypes at codons 136 and 171 in 120 Iranian Ghezel sheep breeds were studied using allele-specific PCR amplification and compared with the well-known sheep breeds in North America, the United States and Europe. The frequency of V allele and VV genotype at codon 136 of Ghezel sheep breed was significantly lower than AA and AV. At codon 171, the frequency of allele H was significantly lower than Q and R. Despite the similarities of PrP genotypes at codons 136 and 171 between Iranian Ghezel sheep breeds and some of the studied breeds, significant differences were found with others. Planning of effective breeding control and successful eradication of susceptible genotypes in Iranian Ghezel sheep breeds will not be possible unless the susceptibility of various genotypes in Ghezel sheep breeds to natural or experimental scrapie has been elucidated.Key words: scrapie, Ghezel sheep breed, PrP genotyping, allele specific amplification, codon 136, codon 171Scrapie was first described in England in 1732,¹ and it is an infectious neurodegenerative fatal disease of sheep and goats belonging to the group of transmissible subacute spongiform encephalopathies (TSEs), along with bovine spongiform encephalopathy (BSE), chronic wasting disease and Creutzfeldt-Jakob disease.^2,3 The term prion, proteinaceous infectious particles, coined by Stanley B. Prusiner, was introduced, and he presents the idea that the causal agent is a protein.⁴ Prion proteins are discovered in two forms, the wild-type form (PrP^c) and the mutant form (PrP^Sc).⁵ Although scrapie is an infectious disease, the susceptibility of sheep is influenced by genotypes of the prion protein (PrP) gene.^2,6 Researchers have found that the PrP allelic variant alanine/arginine/arginine (ARR) at codons 136, 154 and 171 is associated with resistance to scrapie in several breeds.^7–14 Most of the sheep populations in the Near East and North African Region (84% of the total population of 255 million) are raised in Iran, Turkey, Pakistan, Sudan, Algeria, Morocco, Afghanistan, Syria and Somalia.¹⁵ In 2003, the Iranian sheep population was estimated at 54,000,000 head. The Ghezel sheep breed, which also is known as Kizil-Karaman, Mor-Karaman, Dugli, Erzurum, Chacra, Chagra, Chakra, Gesel, Gezel, Kazil, Khezel, Khizel, Kizil, Qezel, Qizil and Turkish Brown, originated in northwestern Iran and northeastern Turkey. By considering sheep breeds as one of the main sources of meat, dairy products and related products, a global screening attempt is started in different areas. In compliance with European Union Decision 2003/100/EC, each member state has introduced a breeding program to select for resistance to TSEs in sheep populations to increase the frequency of the ARR allele. A similar breeding program is established in United States and Canada. The Near East and North African Region still needs additional programs to help the global plan of eradication of scrapie-susceptible genotypes. The current study was the first to assess the geographical and molecular variation of codons 136 and 171 polymorphism between Iranian Ghezel sheep breed and well-known sheep breeds.Polymorphism at codon 136 is associated with susceptibility to scrapie in both experimental and natural models.^10,11,13,16 17 and Austrian Carynthian sheep.¹⁸ Swiss White Alpine showed higher frequency of allele V at position 136 than Swiss Oxford Down, Swiss Black-Brown Mountain and Valais Blacknose.¹⁹ Comparison of polymorphism at codon 136 in the current study with some of other breeds (20 some flock of Hampshire sheep²¹ with current study, but the frequency of it is higher than that of some other breeds.

Table 1

Comparison of PrP allelic and genotype frequencies at codon 136 in different breeds

Contrasting expression of canonical Wnt signaling reporters TOPGAL, BATGAL and Axin2(LacZ) during murine lung development and repair

Canonical WNT signaling plays multiple roles in lung organogenesis and repair by regulating early progenitor cell fates: investigation has been enhanced by canonical Wnt reporter mice, TOPGAL, BATGAL and Axin2(LacZ). Although widely used, it remains unclear whether these reporters convey the same information about canonical Wnt signaling. We therefore compared beta-galactosidase expression patterns in canonical Wnt signaling of these reporter mice in whole embryo versus isolated prenatal lungs. To determine if expression varied further during repair, we analyzed comparative pulmonary expression of beta-galactosidase after naphthalene injury. Our data show important differences between reporter mice. While TOPGAL and BATGAL lines demonstrate Wnt signaling well in early lung epithelium, BATGAL expression is markedly reduced in late embryonic and adult lungs. By contrast, Axin2(LacZ) expression is sustained in embryonic lung mesenchyme as well as epithelium. Three days into repair after naphthalene, BATGAL expression is induced in bronchial epithelium as well as TOPGAL expression (already strongly expressed without injury). Axin2(LacZ) expression is increased in bronchial epithelium of injured lungs. Interestingly, both TOPGAL and Axin2(LacZ) are up regulated in parabronchial smooth muscle cells during repair. Therefore the optimal choice of Wnt reporter line depends on whether up- or down-regulation of canonical Wnt signal reporting in either lung epithelium or mesenchyme is being compared.     

Circulating vascular progenitor cells and central arterial stiffness in polycystic ovary syndrome

Objective

Subjects with Polycystic ovarian syndrome (PCOS) are at increased risk of Type 2 diabetes mellitus (T2DM). The mechanism of this enhanced risk is unclear. Circulating vascular progenitor cells (VPC) are immature bone marrow derived cells capable of differentiating into mature endothelial cells. VPC number/function and central arterial stiffness predict cardio-metabolic disease in at-risk populations.

Design

We studied VPC and arterial stiffness measures in non-obese PCOS subjects as compared to age and body mass index (BMI) matched healthy controls in a cross–sectional study.

Methods

Fourteen subjects with PCOS and 12 controls of similar age, BMI (all <30 kg/m²) and metabolic profile were studied. VPC number and in vitro function were studied by flow cytometry and tube formation assays respectively. Augmentation index (AIx), a measure of central arterial stiffness, and central (aortic) blood pressures (BP) were measured by applanation tonometry.

Results

Subjects with PCOS had a reduced number, mean±SEM, of circulating CD34⁺133⁺ VPCs (317.5±51.0 vs. 558.3±101.2, p = 0.03) and impaired in vitro tube formation (completed tube area 1.0±0.06 vs. 1.2±0.05×10⁶ µm² p = 0.02). PCOS subjects had significantly higher AIx (18.4±1.9% vs. 4.9±2.0%) and this difference remained significant even after adjustments for age, BMI and smoking (p = 0.003) in multivariate analyses. Central systolic and pulse pressure were higher in PCOS subjects but these differences were not statistically significant after adjustment for age. Brachial systolic and pulse pressures were similar. VPC number/function and arterial stiffness or BP measures were not correlated.

Conclusions

Non-obese PCOS is characterized by a reduced VPC number, impaired VPC function and increased central arterial stiffness. These changes in novel vascular risk markers may explain the enhanced risk of T2DM and CVD in PCOS.     

Correlation of circulating omentin-1 with bone mineral density in multiple sclerosis: the crosstalk between bone and adipose tissue

Background

Patients with multiple sclerosis (MS) are at increased risk of osteoporosis and fractures. Adipose tissue-derived adipokines may play important roles in the osteoimmunology of MS. In order to determine whether omentin-1 and vaspin may be related to bone health in MS patients, we compared circulating levels of these recently identified adipokines, between MS patients and healthy controls.

Methods

A total of 35 ambulatory MS patients with relapsing-remitting courses were compared with 38 age- and sex-matched healthy controls. Bone mineral density (BMD) was determined for the lumbar spine (L2–L4) and the proximal femur using dual-energy x-ray absorptiometry. Circulating omentin-1, vaspin, osteocalcin, osteopontin, osteoprotegerin, the receptor activator of nuclear factor-κB ligand, matrix metalloproteinase 9, C-reactive protein and 25-hydroxy vitamin D levels were evaluated by highly specific enzyme-linked immunosorbent assay methods.

Results

There was no significant difference between the two groups regarding bone-related cytokines, adipocytokines, and the BMD measurements of patients with MS and the healthy controls. However, in multiple regression analysis, serum omentin-1 levels were positively correlated with BMD at the femoral neck (β = 0.49, p = 0.016), total hip (β = 0.42, p = 0.035), osteopontin (β = 0.42, p = 0.030) and osteocalcin (β = 0.53, p = 0.004) in MS patients. No correlations were found between vaspin, biochemical, and BMD measures in both groups.

Conclusions

Elevated omentin-1 serum levels are correlated with BMD at the femoral neck and the serum levels of osteocalcin and osteopontin in MS patients. Therefore, there is crosstalk between adipose tissue and bone in MS.     

Eukaryotic richness in the abyss: insights from pyrotag sequencing

Background

The deep sea floor is considered one of the most diverse ecosystems on Earth. Recent environmental DNA surveys based on clone libraries of rRNA genes confirm this observation and reveal a high diversity of eukaryotes present in deep-sea sediment samples. However, environmental clone-library surveys yield only a modest number of sequences with which to evaluate the diversity of abyssal eukaryotes.

Methodology/Principal Findings

Here, we examined the richness of eukaryotic DNA in deep Arctic and Southern Ocean samples using massively parallel sequencing of the 18S ribosomal RNA (rRNA) V9 hypervariable region. In very small volumes of sediments, ranging from 0.35 to 0.7 g, we recovered up to 7,499 unique sequences per sample. By clustering sequences having up to 3 differences, we observed from 942 to 1756 Operational Taxonomic Units (OTUs) per sample. Taxonomic analyses of these OTUs showed that DNA of all major groups of eukaryotes is represented at the deep-sea floor. The dinoflagellates, cercozoans, ciliates, and euglenozoans predominate, contributing to 17%, 16%, 10%, and 8% of all assigned OTUs, respectively. Interestingly, many sequences represent photosynthetic taxa or are similar to those reported from the environmental surveys of surface waters. Moreover, each sample contained from 31 to 71 different metazoan OTUs despite the small sample volume collected. This indicates that a significant faction of the eukaryotic DNA sequences likely do not belong to living organisms, but represent either free, extracellular DNA or remains and resting stages of planktonic species.

Conclusions/Significance

In view of our study, the deep-sea floor appears as a global DNA repository, which preserves genetic information about organisms living in the sediment, as well as in the water column above it. This information can be used for future monitoring of past and present environmental changes.