Soluble CD163 is not increased in visceral fat and steatotic liver and is even suppressed by free fatty acids in vitro

Visceral fat differs from subcutaneous fat by higher local inflammation and increased release of IL-6 and free fatty acids (FFA) which contribute to hepatic steatosis. IL-6 has been shown to upregulate the monocyte/macrophage specific receptor CD163 whose soluble form, sCD163, is increased in inflammatory diseases. Here, it was analyzed whether CD163 and sCD163 are differentially expressed in the human fat depots and fatty liver. CD163 mRNA and protein were similarly expressed in paired samples of human visceral and subcutaneous fat, and comparable levels in portal venous and systemic venous blood of liver-healthy controls indicate that release of sCD163 from visceral adipose tissue was not increased. CD163 was also similarly expressed in steatotic liver when compared to non-steatotic tissues and sCD163 was almost equal in the respective sera. Concentrations of sCD163 were not affected when passing the liver excluding substantial hepatic removal/release of this protein. A high concentration of IL-6 upregulated CD163 protein while physiological doses had no effect. However, sCD163 was not increased by any of the IL-6 doses tested. FFA even modestly decreased CD163 and sCD163. The anti-inflammatory mediators fenofibrate, pioglitazone, and eicosapentaenoic acid (EPA) did not influence sCD163 levels while CD163 was reduced by EPA. These data suggest that in humans neither visceral fat nor fatty liver are major sources of sCD163.

Quantitative analysis of arachidonic acid, endocannabinoids, N-acylethanolamines and steroids in biological samples by LCMS/MS: Fit to purpose.

Arachidonic acid (5Z,8Z,11Z,14Z-eicosatetraenoic acid; C20:4) (arachidonate, AA) is a vital polyunsaturated omega-6 fatty acid (PUFA) without its presence the mammalian brain, muscles, and possibly other organs cannot develop or function [1] and [2]. AA fulfils numerous known and possibly yet unknown functions as integral part of mammalian phospholipid membranes and as free AA which also acts as a precursor of a variety of biologically active lipid mediators generally referred to as eicosanoids (e.g., prostaglandins, leukotrienes). A more recent class of eicosanoids is composed of the endogenous cannabinoids (endocannabinoids) 2-arachidonoyl glycerol (2-AG) and arachidonoyl ethanolamide (anandamide, AEA), which act on cannabinoid CB1 and CB2 receptors but also modulate ion channels and nuclear receptors [3] and [4]. In recent years, the role of endocannabinoids as prominent anti-inflammatory and neuromodulatory eicosanoids has been shown by numerous studies [5].

n-fatty acids of shale partings in the Franciscan bedded cherts

Normal saturated fatty acid (n-fatty acid) in marine sediments from coastal and pelagic environments were analyzed. The coastal sediments contain both short-chained n-fatty acids with carbon numbers from 12 to 18 and long-chained acids from 22 to 32, whereas the pelagic sediments contain predominantly short-chained acids. The relative abundance of short-chained to long-chained n-fatty acids, expressed by the molar ratio C16/C26, can be an indicator to assess the depositional environment of sedimentary rocks. The ratio of long-chained n-fatty acids (C22-C32) to the total n-fatty acids also has the potential to discriminate sedimentary environments. The indicators based on the n-fatty acids were applied to the Franciscan bedded cherts. The result shows that the bedded cherts had deposited in continuous environments from the pelagic to the coastal. This is in harmony with the same inference based on major, trace and rare earth elements and normal paraffins.

(Table 2) Fatty acid profile of blubber from harp seals and hooded seals from the Greenland Sea and Denmark Strait

Sub-Arctic marine ecosystems are some of the most productive ecosystems in the world's oceans. The capacity of herbivorous zooplankton, such as Calanus, to biosynthesize and store large amounts of lipids during the short and intense spring bloom is a fundamental adaptation which facilitates the large production in these ecosystems. These energy-rich lipids are rapidly transferred through the food chain to Arctic seals. The fatty acids and stable isotopes from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) off East Greenland as well as their potential prey, were analysed. The results were used to describe the lipid dynamics and energy transfer in parts of the East Greenland ecosystem. Even if the two seal species showed considerable overlap in diet and occurred at relatively similar trophic levels, the fatty acid profiles indicated that the bases of the food chains of harp and hooded seals were different. The fatty acids of harp seals originate from diatom-based food chain, whereas the fatty acids of hooded seals originate from dinoflagellate and the prymnesiophyte Phaeocystis pouchetii-based food chain. Stable isotope analyses showed that both species are true carnivores on the top of their food chains, with hooded seal being slightly higher on the food chain than harp seal.

Fatty acids, alcohols and hydrocarbons of microbial mats from Lake 2A on Kiritimati Island

Modern microbial mats are widely recognized as useful analogs for the study of biogeochemical processes relevant to paleoenvironmental reconstruction in the Precambrian. We combined microscopic observations and investigations of biomarker composition to investigate community structure and function in the upper layers of a thick phototrophic microbial mat system from a hypersaline lake on Kiritimati (Christmas Island) in the Northern Line Islands, Republic of Kiribati. In particular, an exploratory incubation experiment with 13C-labeled bicarbonate was conducted to pinpoint biomarkers from organisms actively fixing carbon. A high relative abundance of the cyanobacterial taxa Aphanocapsa and Aphanothece was revealed by microscopic observation, and cyanobacterial fatty acids and hydrocarbons showed 13C-uptake in the labeling experiment. Microscopic observations also revealed purple sulfur bacteria (PSB) in the deeper layers. A cyclic C19:0 fatty acid and farnesol were attributed to this group that was also actively fixing carbon. Background isotopic values indicate Calvin-Benson cycle-based autotrophy for cycC19:0 and farnesol-producing PSBs. Biomarkers from sulfate-reducing bacteria (SRB) in the top layer of the mat and their 13C-uptake patterns indicated a close coupling between SRBs and cyanobacteria. Archaeol, possibly from methanogens, was detected in all layers and was especially abundant near the surface where it contained substantial amounts of 13C-label. Intact glycosidic tetraether lipids detected in the deepest layer indicated other archaea. Large amounts of ornithine and betaine bearing intact polar lipids could be an indicator of a phosphate-limited ecosystem, where organisms that are able to substitute these for phospholipids may have a competitive advantage.

Occurrence of metazoans, and gut pigments and fatty acid composition of Acartia bifilosa in ice and under-ice water samples from Santala Bay

A field study was conducted in Santala Bay with weekly samplings during February and March 2000. Ice thickness was 20-28 cm, snow cover 0-1 cm. The under-ice water column was stratified with a cold (-0.3 - 0.2°C) and less saline (S = 2.1-4.9) interface layer. Concentrations of particulate organic carbon (0.5-5.8 mg POC/l) and algal pigments (0.3-18.2 µg chlorophyll a/l) were higher in the ice than in the water (0.2-0.5 mg POC/l, 1.6-7.1 µg chlorophyll a/l) and peaked mostly in the bottom part of the ice. The thin ice and almost lacking snow cover had favoured an early ice-algal and phytoplankton bloom. The diversity of metazoans was low, with six species in the ice and eight species in the under-ice water. The rotifer Synchaeta cf. littoralis dominated both in ice and water, with maximum abundances of 230 individuals/l in the bottom part of the ice. Rotifer eggs were also observed in the ice. Baltic sea ice seems to be a suitable habitat for rotifers. Nauplii and copepodids of the calanoid Acartia longiremis in the under-ice water showed some herbivorous feeding (<0.1-0.23 ng gut pigment/individual), but analysis of fatty acids, fatty alcohols and biomarker ratios indicated a more omnivorous/carnivorous diet. Despite low temperatures, this copepod showed growth and development below the ice, doubling in numbers (mainly CI, CII) from 118 to 230 individuals m during the third week of March.

Lithology, stage, organic carbon, d13C, hydrocarbons and fatty acids at DSDP Hole 93-603B

Organic-matter-rich Upper Cretaceous claystones from DSDP Hole 603B, lower continental rise, had organic carbon values ranging from 1.7 to 13.7%, C/N ratios from 32 to 72, and d13C values from -23.5 to -27.1 per mil. Lipid class maxima for the unbound alkanes (C29 and C31), unbound fatty acids (C28 and C30), and bound fatty acids (C24, C26 , and C28) and the strong odd-carbon and even-carbon preferences, respectively, suggested that the organic matter in these sediments was partially the result of input from continental plant waxes. Transport of the organic-matter-rich sediments to the deep sea from the near-shore environment probably resulted from turbiditic flow under oxygen-stressed conditions.