Investigation of the functions of n-3 very-long-chain PUFAs in skin using in vivo Atlantic salmon and in vitro human and fish skin models

The purpose of this study was to investigate the effect of dietary n-3 very-long-chain PUFA (n-3 VLC-PUFA) on the maturation and development of skin tissue in juvenile Atlantic salmon (Salmo salar) in vivo, as well as their effects on skin keratocyte and human skin fibroblast cell migration in vitro. Atlantic salmon were fed different dietary levels of n-3 VLC-PUFA from an initial weight of 6 g to a final weight of 11 g. Changes in skin morphology were analysed at two time points during the experiment, and the effects on skin tissue fatty acid composition were determined. Additionally, in vitro experiments using human dermal fibroblasts and primary Atlantic salmon keratocytes were conducted to investigate the effect of VLC-PUFA on the migration capacity of the cells. The results demonstrated that increased dietary levels of n-3 VLC-PUFA led to an increased epidermis thickness and more rapid scale maturation in Atlantic salmon skin in vivo, leading to a more mature skin morphology, and possibly more robust skin, at an earlier life stage. Additionally, human skin fibroblasts and salmon skin keratocytes supplemented with n-3 VLC-PUFA in vitro showed more rapid migration, indicating potentially beneficial effects of VLC-PUFA in wound healing. In conclusion, VLC-PUFA may have beneficial effects on skin tissue development, function and integrity.

DIY Flap Monitoring: The Glucose Index

Background

Flap loss is reduced by monitoring, which detects vascular compromise. Glucose levels vary in suffering flaps; therefore, we aimed to show that monitoring flaps with glucose pinprick test is a cheap, reliable, ubiquitous, and easy method.

Methods

We reviewed a prospectively kept database. A pinprick test was performed to measure systemic and flap glucose levels. A glucose index (GI; flap glucose/systemic glucose) was calculated. Comparison between the groups (with occlusive event, and without occlusive event) was done.

Results

In total, 32 flaps in 29 consecutive patients were included. Eleven (34%) were free flaps. Of these, one (9%) was explored twice. Initially, salvage was achieved. However, 36 hours later, a second exploration was needed but was unsuccessful. Of the 21 pedicled flaps (66%), one (5%) needed exploration (suture release), and three (14%) had partial losses that were not clinically relevant. On the ROC curve, we found a cut-off value for a GI of 0.49 or less with a sensitivity of 95% [95% confidence interval (CI): 75.1 to 99.9%] and a specificity of 100% (95% CI: 98.5 to 100%), with a positive predictive value of 100% (95% CI: 81.5 to 100%) and a negative predictive value of 99.6% (95% CI: 97.8 to 100%) for flap suffering.

Conclusions

The GI, as a complement, assists in defining treatment approach. It is an easy, reliable, accessible method that can be performed by nonmedical personnel. Its main drawback is the inability to monitor buried or hard to reach flaps.

Dietary Level of the Omega-3 Fatty Acids EPA and DHA Influence the Flesh Pigmentation in Atlantic Salmon

Atlantic salmon with a start weight of 53 g were fed diets with different levels of EPA and DHA or a diet with 1 : 1 EPA+DHA (0%, 1.0%, and 2.0% of the diet). At 400 g, all fish groups were mixed and equally distributed in new tanks and fed three diets with 0.2%, 1.0%, or 1.7% of EPA+DHA. At 1200 g, the fish were transferred to seawater pens where they were fed the same three diets until they reached a slaughter size of 3.5 kg. The fillet concentration of astaxanthin and its metabolite idoxanthin was analysed before transfer to seawater pens at 1200 g and at slaughter. The fatty acid composition in the fillet was also analysed at the same time points. Salmon fed low levels of EPA and DHA had lower fillet astaxanthin concentration and higher metabolic conversion of astaxanthin to idoxanthin compared to salmon fed higher dietary levels of EPA and/or DHA. DHA had a more positive effect on fillet astaxanthin concentrations than EPA. There were positive correlations between fillet DHA, EPA, sum N-3 fatty acids, and fillet astaxanthin concentration. A negative correlation was found between the concentration of N-6 fatty acids in the fillet and the astaxanthin concentration.

Increasing dietary levels of the n-3 long-chain PUFA, EPA and DHA, improves the growth, welfare, robustness and fillet quality of Atlantic salmon in sea cages

The present study evaluated the effects of increasing the dietary levels of EPA and DHA in Atlantic salmon (Salmo salar) reared in sea cages, in terms of growth performance, welfare, robustness and overall quality. Fish with an average starting weight of 275 g were fed one of four different diets containing 10, 13, 16 and 35 g/kg of EPA and DHA (designated as 1·0, 1·3, 1·6 and 3·5 % EPA and DHA) until they reached approximately 5 kg. The 3·5 % EPA and DHA diet showed a significantly beneficial effect on growth performance and fillet quality compared with all other diets, particularly the 1 % EPA and DHA diet. Fish fed the diet containing 3·5 % EPA and DHA showed 400-600 g higher final weights, improved internal organ health scores and external welfare indicators, better fillet quality in terms of higher visual colour score and lower occurrence of dark spots and higher EPA and DHA content in tissues at the end of the feeding trial. Moreover, fish fed the 3·5 % EPA and DHA diet showed lower mortality during a naturally occurring cardiomyopathy syndrome outbreak, although this did not reach statistical significance. Altogether, our findings emphasise the importance of dietary EPA and DHA to maintain good growth, robustness, welfare and fillet quality of Atlantic salmon reared in sea cages.

DHA Modulates Immune Response and Mitochondrial Function of Atlantic Salmon Adipocytes after LPS Treatment

Adipocytes play a central role in overall energy homeostasis and are important contributors to the immune system. Fatty acids (FAs) act as signaling molecules capable to modulate adipocyte metabolism and functions. To identify the effects of two commonly used FAs in Atlantic salmon diets, primary adipocytes were cultured in the presence of oleic (OA) or docosahexaenoic (DHA) acid. DHA decreased adipocyte lipid droplet number and area compared to OA. The increase in lipid load in OA treated adipocytes was paralleled by an increase in iNOS activity and mitochondrial SOD2-GFP activity, which was probably directed to counteract increase in oxidative stress. Under lipopolysaccharide (LPS)-induced inflammation, DHA had a greater anti-inflammatory effect than OA, as evidenced by the higher SOD2 activity and the transcriptional regulation of antioxidant enzymes and pro- and anti-inflammatory markers. In addition, DHA maintained a healthy mitochondrial structure under induced inflammation while OA led to elongated mitochondria with a thin thread like structures in adipocytes exposed to LPS. Overall, DHA possess anti-inflammatory properties and protects Atlantic salmon against oxidative stress and limits lipid deposition. Furthermore, DHA plays a key role in protecting mitochondria shape and function.

Impact of Reduced Dietary Levels of Eicosapentaenoic Acid and Docosahexaenoic Acid on the Composition of Skin Membrane Lipids in Atlantic Salmon ( Salmo salar L.)

Membrane lipids, including sphingolipids and glycerol-phospholipids, are essential in maintaining the skin's barrier function in mammals, but their composition in fish skin and their response to diets have not been evaluated. This study investigated the impacts of reducing dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on membrane lipids in the skin of Atlantic salmon through a 26 week feeding regime supplying different levels (0-2.0% of dry mass) of EPA/DHA. Ceramide, glucosylceramide, sphingomyelin, sphingosine, and sphinganine in salmon skin were analyzed for the first time. Higher concentrations of glucosylceramide and sphingomyelin and higher ratios of glucosylceramide/ceramide and sphingomyelin/ceramide were detected in the deficient group, indicating interruptions in sphingolipidomics. Changes in the glycerol-phospholipid profile in fish skin caused by reducing dietary EPA and DHA were observed. There were no dietary impacts on epidermal thickness and mucus-cell density, but the changes in the phospholipid profile suggest that low dietary EPA and DHA may interrupt the barrier function of fish skin.

Effects of dietary n-3 fatty acids on Toll-like receptor activation in primary leucocytes from Atlantic salmon (Salmo salar)

The shortage of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the international markets has led to increasing substitution of fish oil by plant oils in Atlantic salmon (Salmo salar) feed and thereby reducing the EPA and DHA content in salmon. However, the minimum required levels of these fatty acids in fish diets for securing fish health are unknown. Fish were fed with 0, 1 or 2% EPA or DHA alone or in combination of both over a period, growing from 50 to 400 g. Primary head kidney leucocytes were isolated and stimulated with Toll-like receptor (TLR) ligands to determine if EPA and DHA deficiency can affect expression of important immune genes and eicosanoid production. Several genes related to viral immune response did not vary between groups. However, there was a tendency that the high-level EPA and DHA groups expressed lower levels of IL-1β in non-stimulated leucocytes. These leucocytes were also more responsive to the TLR ligands, inducing higher expression levels of IL-1β and Mx1 after stimulation. The levels of prostaglandin E2 and leukotriene B4 in serum and media from stimulated leucocytes were lower in both low and high EPA and DHA groups. In conclusion, leucocytes from low EPA and DHA groups seemed to be less responsive towards immunostimulants, like TLR ligands, indicating that low levels or absence of dietary EPA and DHA may have immunosuppressive effects.

Gene expression profile during proliferation and differentiation of rainbow trout adipocyte precursor cells

BACKGROUND

Excessive accumulation of adipose tissue in cultured fish is an outstanding problem in aquaculture. To understand the development of adiposity, it is crucial to identify the genes which expression is associated with adipogenic differentiation. Therefore, the transcriptomic profile at different time points (days 3, 8, 15 and 21) along primary culture development of rainbow trout preadipocytes has been investigated using an Agilent trout oligo microarray.

RESULTS

Our analysis identified 4026 genes differentially expressed (fold-change >3) that were divided into two major clusters corresponding to the main phases observed during the preadipocyte culture: proliferation and differentiation. Proliferation cluster comprised 1028 genes up-regulated from days 3 to 8 of culture meanwhile the differentiation cluster was characterized by 2140 induced genes from days 15 to 21. Proliferation was characterized by enrichment in genes involved in basic cellular and metabolic processes (transcription, ribosome biogenesis, translation and protein folding), cellular remodelling and autophagy. In addition, the implication of the eicosanoid signalling pathway was highlighted during this phase. On the other hand, the terminal differentiation phase was enriched with genes involved in energy production, lipid and carbohydrate metabolism. Moreover, during this phase an enrichment in genes involved in the formation of the lipid droplets was evidenced as well as the activation of the thyroid-receptor/retinoic X receptor (TR/RXR) and the peroxisome proliferator activated receptors (PPARs) signalling pathways. The whole adipogenic process was driven by a coordinated activation of transcription factors and epigenetic modulators.

CONCLUSIONS

Overall, our study demonstrates the coordinated expression of functionally related genes during proliferation and differentiation of rainbow trout adipocyte cells. Furthermore, the information generated will allow future investigations of specific genes involved in particular stages of fish adipogenesis.

EPA, DHA, and Lipoic Acid Differentially Modulate the n-3 Fatty Acid Biosynthetic Pathway in Atlantic Salmon Hepatocytes

The aim of the present study was to investigate how EPA, DHA, and lipoic acid (LA) influence the different metabolic steps in the n-3 fatty acid (FA) biosynthetic pathway in hepatocytes from Atlantic salmon fed four dietary levels (0, 0.5, 1.0 and 2.0%) of EPA, DHA or a 1:1 mixture of these FA. The hepatocytes were incubated with [1-¹⁴C] 18:3n-3 in the presence or absence of LA (0.2 mM). Increased endogenous levels of EPA and/or DHA and LA exposure both led to similar responses in cells with reduced desaturation and elongation of [1-¹⁴C] 18:3n-3 to 18:4n-3, 20:4n-3, and EPA, in agreement with reduced expression of the Δ6 desaturase gene involved in the first step of conversion. DHA production, on the other hand, was maintained even in groups with high endogenous levels of DHA, possibly due to a more complex regulation of this last step in the n-3 metabolic pathway. Inhibition of the Δ6 desaturase pathway led to increased direct elongation to 20:3n-3 by both DHA and LA. Possibly the route by 20:3n-3 and then Δ8 desaturation to 20:4n-3, bypassing the first Δ6 desaturase step, can partly explain the maintained or even increased levels of DHA production. LA increased DHA production in the phospholipid fraction of hepatocytes isolated from fish fed 0 and 0.5% EPA and/or DHA, indicating that LA has the potential to further increase the production of this health-beneficial FA in fish fed diets with low levels of EPA and/or DHA.

Interplay of adiponectin, TNFα and insulin on gene expression, glucose uptake and PPARγ, AKT and TOR pathways in rainbow trout cultured adipocytes

Adipose tissue is being increasingly recognized as an important endocrine organ that produces and releases a variety of factors. In the present study we have evaluated in primary cultures of rainbow trout adipocytes, obtained from visceral adipose tissue, the interplay of the adiponectin system, TNFα and insulin at a transcriptional level and, their effects on the adipogenic transcription factor PPARγ, as well as on the activation of main insulin signaling pathways. Likewise, the implication of these adipokines in the regulation of glucose uptake in the adipocyte and their interactions with insulin or IGF-I were also evaluated. Similarly to the mammalian model, insulin enhanced adiponectin gene expression, while it exerted a negative modulation on adiponectin receptors. TNFα increased the mRNA levels of adiponectin receptor 1, but neither adiponectin nor TNFα modulated each other expression. Therefore, the reciprocal suppressive effect of both adipokines previously reported in mammals was not present in this model. Furthermore, the anti-adipogenic effect of TNFα was revealed by the down-regulation of PPARγ at a protein level, meanwhile adiponectin increased PPARγ expression in insulin-stimulated adipocytes, supporting its insulin-sensitizing role. Both adipokines stimulated glucose uptake without modifying AKT or TOR phosphorylation; however, glucose uptake in insulin-treated adipocytes was enhanced by TNFα but not by adiponectin. All in all, these results contribute to gain knowledge on the role of adipokines in rainbow trout adipose tissue and, to better understand the mechanisms that regulate glucose metabolism in this species.

Adipose tissue and liver metabolic responses to different levels of dietary carbohydrates in gilthead sea bream (Sparus aurata)

This study analyzes the effects of replacing dietary lipids by carbohydrates and carbohydrates by fiber on gilthead sea bream growth, as well as lipid and glucose metabolism in adipose tissue and liver over the course of a 15-week feeding trial. Six different diets were formulated and fish were classified into two experimental groups sharing one diet. In the first group (LS), fish were fed four diets where lipids were reduced (23%-17%) by increasing carbohydrates (12%-28%) and, the second group (SF) consisted on three diets where the amount of carbohydrates (28%-11%) was exchanged at expenses of fiber (1%-18%). Differences in growth were not observed; nevertheless, the hepatosomatic index was positively related to dietary starch levels, apparently not due to enhanced hepatic lipogenesis, partly supported by unchanged G6PDH expression. In the LS group, lipogenic activity of adipose tissue was stimulated with low-lipid/high-carbohydrate diets by up-regulating G6PDH expression and a tendency to increase FAS, and promoted carbohydrate utilization versus fatty acid oxidation by modulating the transcription factors LXRα, PPARα and PPARβ expression. In the SF group, PPARs and LXRα increased parallel to fiber levels in adipose tissue. Furthermore, an adaptation of hepatic GK to dietary starch inclusion was observed in both groups; however, the lack of effects on G6Pase expression indicated that gluconeogenesis was not nutritionally regulated under the conditions examined. Overall, metabolic adaptations directed to an efficient use of dietary carbohydrates are present in gilthead sea bream, supporting the possibility of increasing carbohydrate or fiber content in diets for aquaculture sustainability.

[Nonpuerperal breast abscess caused by Finegoldia magna]

Finegoldia magna is a species of strictly anaerobic gram-positive cocci, arranged in pairs, tetrads, and clusters. These organisms are components of the normal flora of the skin, gastrointestinal and genitourinary female tracts, and oral cavity. They are asaccharolytic and their major energy sources are aminoacids and peptones. The species is usually isolated in polymicrobial cultures from abscesses, soft tissue infections, bone and joints. In the case herein presented, F. magna was recovered in pure culture from a nonpuerperal breast abscess, which adds to the two reported cases in related literature. Species identification was performed by special potency disks, standard bacteriological anaerobic tests, and production of saccharolytic and proteolytic enzymes. Antimicrobial susceptibility testing was performed by using the epsilometric test. The agents assayed and MICs (microg/ml) values were: penicillin, 0.064; cephalotin, 1; metronidazole, 0.25; minocycline, < 0.016; azithromycin, 4; claritromycin, 2. We would like to highlight the importance of identifying anaerobic gram-positive cocci at species level, and of determining the antimicrobial susceptibility pattern, when they are isolated in pure culture from appropriate samples, as in the case presently reported.

[Survey of the attitude of primary care physicians towards AIDS]

A representative group of primary care physicians from Areas 4 and 5 of the Institut Català de la Salut were surveyed in orden to know their opinion about the spreading of HIV infection, the value of serological tests and the methods to prevent the infection of health care providers. More than half of the physicians (58.5%) had never been in contact with an HIV infected patient. Of the surveyed physicians, 47.2% believe that it is necessary to spread out more information on preventive measures amongst health professionals. 48.4% believe that confidentiality is important but only 16.9% consider it is important to obtain an informed consent to perform serological testing and another 22.5% mainly trust systematic serological testing. Primary care can play an important role avoiding the spread of HIV infection and, in fact, the importance of preventive measures and confidentiality are assumed by an elevated percentage of health professionals. The usefulness of serological testing, however, is not properly assessed valued and little importance is granted to the patient's consent for their performance.

[A study on the role of DNA methylation within hCG and hPL genes in trophoblastic disease]

It has been shown that the extent of methylation of cytocine in DNA is inversely correlated with gene expression in many cases. The DNAs extracted from placental tissue, hydatidiform mole and choriocarcinoma tissue were examined to see whether the extent of cytocine methylation is correlated to the gene expression of placental peptide hormones and the transformation of trophoblast. First of all we measured the amount of methylated cytocine per total DNA with HPLC. We then examined cytocine methylation in hCG alpha,beta and hPL genes using methylation sensitive (Hha I, Hpa II) and non sensitive (Msp I) restriction enzymes and molecular hybridization. During pregnancy the total amount of methylated cytocine measured with HPLC increases gradually from 0.72 mol.% at first trimester to 0.92 mol.% at term. The DNA of WBC showed a higher level of methylated cytocine than placental DNA. The extent of DNA methylation in the peptide hormone genes increases during placental development. Hypomethylation in the hCG alpha gene was also seen in molar tissue which expresses a high amount of hCG. Therefore it is inversely correlated that gene expression of hCG alpha,beta and the extent of DNA cytocine methylation. Furthermore some restriction polymorphisms were observed with Msp I in hCG alpha and hPL genes which might be related to malignant transformation of the trophoblast.