Omega-3 fatty acid-based lipid infusion in patients with chronic plaque psoriasis: results of a double-blind, randomized, placebo-controlled, multicenter trial

Inflammatory Disease Processes and Interactions with Nutrition

Inflammation is a stereotypical physiological response to infections and tissue injury; it initiates pathogen killing as well as tissue repair processes and helps to restore homeostasis at infected or damaged sites. Acute inflammatory reactions are usually self-limiting and resolve rapidly, due to the involvement of negative feedback mechanisms. Thus, regulated inflammatory responses are essential to remain healthy and maintain homeostasis. However, inflammatory responses that fail to regulate themselves can become chronic and contribute to the perpetuation and progression of disease. Characteristics typical of chronic inflammatory responses underlying the pathophysiology of several disorders include loss of barrier function, responsiveness to a normally benign stimulus, infiltration of inflammatory cells into compartments where they are not normally found in such high numbers, and overproduction of oxidants, cytokines, chemokines, eicosanoids and matrix metalloproteinases. The levels of these mediators amplify the inflammatory response, are destructive and contribute to the clinical symptoms. Various dietary components including long chain ω-3 fatty acids, antioxidant vitamins, plant flavonoids, prebiotics and probiotics have the potential to modulate predisposition to chronic inflammatory conditions and may have a role in their therapy. These components act through a variety of mechanisms including decreasing inflammatory mediator production through effects on cell signaling and gene expression (ω-3 fatty acids, vitamin E, plant flavonoids), reducing the production of damaging oxidants (vitamin E and other antioxidants), and promoting gut barrier function and anti-inflammatory responses (prebiotics and probiotics). However, in general really strong evidence of benefit to human health through anti-inflammatory actions is lacking for most of these dietary components. Thus, further studies addressing efficacy in humans linked to studies providing greater understanding of the mechanisms of action involved are required.

Antiproliferative effect of docosahexaenoic acid on adult human keratinocytes in vitro / Antiproliferativni efekat dokosaheksanoične kiseline na adultne humane keratinocite in vitro

Numerous clinical studies demonstrate benefits of dietary supplementation with fish oils in autoimmune diseases and other inflammatory diseases such as psoriasis, multiple sclerosis, systemic lupus erythematodes and so on. Docosahexaenoic acid (DHA) is an omega-3 fatty acid which is abundantly found in fish oil. In the present study we investigated effects of DHA on proliferation of human keratinocytes established from skin of seven adult donors, cultivated in growth medium that allows optimal cell proliferation. We found a dose-dependent inhibition of cell proliferation when keratinocytes were incubated with 6.25, 12.5 and 25 -μM of DHA. Inhibition of proliferative capacity considerably varied in keratinocyte cultures derived from different donors, particularly when incubated with the lowest concentration of the assessed substance. Lactate dehydrogenase-release assay excluded necrosis of cultivated keratinocytes as a cause of decreased proliferation. Our results suggest that DHA may potentially be used as a routine adjuvant therapy, with classical therapy of inflammatory hyperproliferative skin diseases.

Psoriatic Arthritis: A Review

Psoriatic arthritis (PsA) is a seronegative inflammatory spondyloarthropathy occurring in individuals with psoriasis. Psoriasis precedes joint disease in approximately 80% of PsA cases. The clinical course of PsA varies from mild arthritis to a severe, debilitating erosive arthropathy that affects functional capacity and quality of life of patients. The incidence of PsA is gender neutral, but a significant genetic component exists. Hallmark clinical features include dystrophic nail changes in the fingers or toes, dactylitis, and enthesitis. Many drugs indicated for use in rheumatoid arthritis have been found useful in the treatment of PsA, suggesting a similar immune-mediated etiology. Nonsteroidal anti-inflammatory drugs and intraarticular corticosteroids are often sufficient to manage mild PsA. Moderate to severe forms of the disease require the initiation of disease modifying anti-rheumatic drugs. Failure of two disease modifying antirheumatic drugs justifies the initiation of biologic therapy with tumor necrosis factor-α inhibitors.

How prominent are patient-reported outcomes in clinical trials of dermatological treatments?

BACKGROUND

Assessment of symptoms or disease improvement by study participants is an important aspect of assessing new dermatological therapies in clinical trials, especially for chronic skin diseases that lack objective severity markers.

OBJECTIVES

We sought to determine the frequency and prominence of reporting of participants' subjective efficacy outcomes in dermatological clinical trials. Our secondary objective was to determine whether participant and physician outcomes agree in terms of direction and magnitude.

METHODS

Systematic review of 125 randomized controlled trials identified from the Archives of Dermatology, British Journal of Dermatology, Clinical & Experimental Dermatology, Journal of Dermatological Treatment and Journal of the American Academy of Dermatology published between 1994 and 2001 (25 from each). Studies were retrieved in hard copy from the Cochrane Skin Group specialized register of trials and data were abstracted and summarized.

RESULTS

Participant efficacy outcomes were mentioned in some form in only 32 of 125 trials (25.6%, 95% exact confidence interval 18.2-34.2%). Of these 32 studies, participant outcomes were mentioned only in the methods section in two studies, in the methods and results section without further data in nine studies and with further data in 21. Data were presented in figure format only in 12 of these studies and in tables and figures in nine. Participant efficacy outcomes were mentioned in the abstract section in just over half (53%) of the 32 trials that included participant efficacy outcomes. There was not enough information to assess agreement in direction and magnitude of participant vs. assessor outcomes. Overall, only 17 papers (13.6%) clearly declared their main outcome measures beforehand in the introduction or methods section.

CONCLUSIONS

Asking study participants for their views of treatment efficacy seems like a good idea in dermatological clinical trials, yet only about a quarter of the trials examined in this review did so. Even when such information was recorded, it was often poorly and incompletely reported and given low prominence within the trial report. Our study findings call for a more comprehensive uptake for including participant efficacy outcomes alongside other assessor outcomes in clinical trials and, when included, to report those outcomes in full.

Identification of inflammatory and proresolving lipid mediators in bone marrow and their lipidomic profiles with ovariectomy and omega-3 intake

Newly described lipoxygenase (LOX)-generated lipid mediators, that is, resolvins and protectins as well as lipoxins, are both anti-inflammatory and proresolving. We aimed to determine whether these lipid mediators are present in bone marrow and whether their lipidomic profiles are altered following ovariectomy or dietary supplementation with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) ethyl esters. Female rats were ovariectomised or sham-operated. Shams and one ovariectomised group received a diet devoid of omega-3 long-chain polyunsaturated fatty acids. The remaining ovariectomised rats received either 0.5 g EPA or DHA ethyl ester/kg body weight/day for 4 months. Bone marrow was analyzed using both GC to determine fatty acid composition and mediator lipidomics by LC/MS/MS profiling for the presence of LOX-pathway lipid mediators derived from arachidonic acid (AA), EPA, and DHA. LOX-derived products including lipoxins, resolvin D1, resolvin E1, and protectin D1 were identified in bone marrow by the presence of diagnostic ions in their corresponding MS-MS spectra. The proportion of AA relative to DHA and of AA-derived relative to DHA-derived mediators in bone marrow was higher in ovariectomised compared to sham-operated rats. DHA or EPA ethyl ester supplementation increased the percentage of DHA and EPA in bone marrow and increased the proportion of LOX mediators biosynthesized from DHA or EPA, respectively. Given the potent bioactivities of the lipoxins, resolvins, and protectins, the presence and changes in profile postovariectomy and with EPA and DHA ethyl ester supplementation may be of interest in bone marrow function and as a potential source of these mediators in vivo.

[The significance of diet and associated factors in psoriasis]

Psoriasis is a T cell mediated inflammatory skin disease characterized by hyperproliferation and reduced differentiation of epidermal keratinocytes. In severe cases, the disease can result in an insufficient nutritional status which may even be promoted by nutrient-drug interactions. Both the general diet and single food components have been suggested to play a role in etiology and pathogenesis of psoriasis. Fasting periods, vegetarian diets, and diets rich in omega-3 polyunsaturated fatty acids from fish oil have all been associated with improvement in some studies. The most likely explanation is the reduced amounts of arachidonic acid and the increased eicosapentaenoic acid intake resulting in a modulated eicosanoid profile. However, only one of four controlled studies showed a benefit of omega-3 fatty acids compared to placebo. Some psoriasis patients are gluten-sensitive and may benefit from a gluten free diet. The active form of vitamin D exhibits anti-proliferative and immunoregulatory effects and has been shown to be useful in the treatment of psoriasis.

Effect of different lipid emulsions on the immunological function in humans: a systematic review with meta-analysis

BACKGROUND & AIMS

Reports regarding the pro- or anti-inflammatory effects of lipid emulsion used in parenteral nutrition are conflicting. Aim was to assess the effect of different intravenous lipid emulsions on immunological function in humans.

METHODS

We performed a computerized bibliographic search, searched reference lists in trial reports, hand-searched journals and contacted experts in the field. Randomized clinical trials evaluating the immunological effects of different parenteral lipid emulsions were included. Three authors independently performed data extraction, statistical processes were performed by two experts. Immunological parameters were classified by two immunologists as marker of improved or worsened immune function. A meta-analysis with standardized effect size estimation was performed for the comparison between long-chain triglycerides vs. glucose or other fat emulsions.

RESULTS

Of 682 assessed studies, 120 compared the immunological effects of intravenously applied lipid emulsions. Of 30 randomized trials, 14 were included in the meta-analysis. None of the lipid regimens showed any clear effect on the evolution of the immunological status or mortality in humans. Length of hospital stay and stay in the intensive care unit could not be evaluated.

CONCLUSION

We found no evidence that lipid emulsions and in particular those containing long-chain triglycerides have an unfavorable effect on immune function.

n-3 Polyunsaturated fatty acids, inflammation and obesity-related disease

Obese individuals are at increased risk from a range of metabolic diseases, including insulin resistance, dyslipidaemia and hypertension. Adipose tissue is an important endocrine organ, secreting a range of inflammatory mediators, including tumour necrosis factor a and interleukin 6. Circulating concentrations of these cytokines are increased in obesity and may contribute to the pathogenesis of metabolic diseases. The present review considers the evidence linking inflammation and obesity-related disease. The data show that an inflammatory phenotype, measured by serum sialic acid concentration, identifies individuals with insulin resistance, dyslipidaemia and hypertension. Serum sialic acid concentration increases progressively in obese individuals with none, one or multiple features of the metabolic syndrome, independent of BMI. Supplementation with long-chain n-3 polyunsaturated fatty acids has shown anti-inflammatory effects in studies of both healthy populations and in models of chronic inflammatory conditions. The effect on insulin sensitivity has been varied, with both positive and negative effects. This variability may relate to the metabolic characteristics of the study population; individuals with high background inflammation may derive greater benefits from n-3 polyunsaturated fatty acid supplements, suggesting a possible interaction between diet and phenotype. Future research is needed to fully evaluate the role of anti-inflammatory strategies in the dietary management of obesity.

Fish oil: what the prescriber needs to know

There is a general belief among doctors, in part grounded in experience, that patients with arthritis need nonsteroidal anti-inflammatory drugs (NSAIDs). Implicit in this view is that these patients require the symptomatic relief provided by inhibiting synthesis of nociceptive prostaglandin E₂, a downstream product of the enzyme cyclo-oxygenase (COX), which is inhibited by NSAIDs. However, the concept of 'safe' NSAIDs has collapsed following a multiplicity of observations establishing increased risk for cardiovascular events associated with NSAID use, especially but not uniquely with the new COX-2-selective NSAIDs. This mandates greater parsimony in the use of these agents. Fish oils contain a natural inhibitor of COX, reduce reliance on NSAIDs, and reduce cardiovascular risk through multiple mechanisms. Fish oil thus warrants consideration as a component of therapy for arthritis, especially rheumatoid arthritis, in which its symptomatic benefits are well established. A major barrier to the therapeutic use of fish oil in inflammatory diseases is ignorance of its mechanism, range of beneficial effects, safety profile, availability of suitable products, effective dose, latency of effects and instructions for administration. This review provides an evidence-based resource for doctors and patients who may choose to prescribe or take fish oil.

Preparation and physical characterization of a novel marine oil emulsion as a potential new formulation vehicle for lipid soluble drugs

Emulsions often contain vegetable oils such as soybean oil. In this study, a 10% (w/w) of marine mammal oil emulsion was prepared. The effect of a group of emulsifying agents on the stability of the 10% of seal oil emulsion was examined. The emulsifying agents studied were hydrogenated castor oil coated with various polyoxyethylene derivatives. It was found that 2.5% of HCO-40 resulted in the most stable seal oil emulsion. The size of the emulsified droplets defined by their diameters was found to be around 240-270 nm. The initial zeta-potential and pH value of the emulsion were found to be around -27 mV and 3.5, respectively, which decreased over time, to about -31 mV and 2.4, respectively. This is believed to be a result of the hydrolysis of triacylglycerides into free fatty acids in the emulsion. The effect of various amounts of Crodasinic LS-30, a negatively charged surfactant, and Incroqal Behenyl TMS, a positively charged surfactant, on the emulsion was investigated. It was shown that Crodasinic LS-30 had very little effect on the particle size, zeta-potential and pH, while the effect of Incroquat Benhenyl TMS was found to be dependent upon the concentration of the surfactant used.

Diet and psoriasis: experimental data and clinical evidence

Psoriasis is considered as a T-cell-mediated inflammatory skin disease which is characterized by hyperproliferation and poor differentiation of epidermal keratinocytes. While susceptibility to psoriasis is inherited, the disease is influenced by environmental factors such as infections and stress. Diet has been suggested to play a role in the aetiology and pathogenesis of psoriasis. Fasting periods, low-energy diets and vegetarian diets improved psoriasis symptoms in some studies, and diets rich in n-3 polyunsaturated fatty acids from fish oil also showed beneficial effects. All these diets modify the polyunsaturated fatty acid metabolism and influence the eicosanoid profile, so that inflammatory processes are suppressed. Some patients with psoriasis show an elevated sensitivity to gluten. In patients with IgA and/or IgG antigliadin antibodies the symptoms have been shown to improve on a gluten-free diet. The active form of vitamin D, 1,25-dihydroxyvitamin D(3), exhibits antiproliferative and immunoregulatory effects via the vitamin D receptor, and thus is successfully used in the topical treatment of psoriasis. In this review, dietary factors which play a role in psoriasis are assessed and their potential benefit is evaluated. Furthermore, the risk of drug-nutrient interactions in psoriasis therapy is discussed.

Fatty acids from lipids of marine organisms: molecular biodiversity, roles as biomarkers, biologically active compounds, and economical aspects

Because of their characteristic living environments, marine organisms produce a variety of lipids. Fatty acids constitute the essential part of triglycerides and wax esters, which are the major components of fats and oils. Nevertheless, phospholipids and glycolipids have considerable importance and will be taken into account, especially the latter compounds that excite increasing interest regarding their promising biological activities. Thus, in addition to the major polyunsaturated fatty acids (PUFA) such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, a great number of various fatty acids occur in marine organisms, e.g. saturated, mono- and diunsaturated, branched, halogenated, hydroxylated, methoxylated, non-methylene-interrupted. Various unprecedented chemical structures of fatty acids, and lipid-containing fatty acids, have recently been discovered, especially from the most primitive animals such as sponges and gorgonians. This review of marine lipidology deals with recent advances in the field of fatty acids since the end of the 1990s. Different approaches will be followed, mainly developing biomarkers of trophic chains in marine ecosystems and of chemotaxonomic interest, reporting new structures, especially those with biological activities or biosynthetic interest. An important part of this review will be devoted to the major PUFA, their relevance to health and nutrition, their biosynthesis, their sources (usual and promising) and market.

Effectiveness of kukui nut oil as a topical treatment for psoriasis

BACKGROUND

No cure for psoriasis exists for the 1-3% of the American population who suffer from it; however, anecdotal reports from patients with psoriasis visiting Hawaii who purchased kukui nut oil, claim it helped reduce the severity of their lesions.

OBJECTIVE

This pilot study was a double-blind, placebo-controlled clinical trial to determine the effectiveness of kukui nut oil as a topical treatment for psoriasis.

METHODS

Thirty adult subjects (18-78 year) were recruited from the community for a 12-week randomized, double-blind, placebo-controlled pilot study. Subjects were previously diagnosed with mild, stable plaque psoriasis (less than 15% of total body surface area [TBSA]) and agreed to abstain from other treatments during the course of the study. Following a 4-week washout period the subjects were randomized into a treatment group (15 subjects applying kukui nut oil) or a control group (15 applying the mineral oil placebo). Patients were seen every 2 weeks (seven visits at 0, 2, 4, 6, 8, 10, and 12 weeks) by a dermatological nurse practitioner under the general supervision of a board certified dermatologist. Measurable outcomes included evaluation of one targeted lesion and of the overall severity of their psoriasis using clinical evaluation, Psoriasis Area and Sensitivity Index (PASI), Global Severity of Psoriasis Scale, and photographs. Each patient also evaluated their own lesions daily using the Global Severity of Psoriasis Scale, and noted any side-effects or other treatments used.

RESULTS

Although both groups improved, we found no significant difference between the treatment (kukui nut oil) and the placebo (mineral oil) among the 24 out of 30 subjects (80%) who completed the study. No side-effects or adverse events were reported.

CONCLUSION

Kukui nut oil did not significantly reduce symptoms of psoriasis; however, this was a small pilot study, and the use of this oil cannot be dismissed without using a larger study population of patients with psoriasis.

Topical application of natural honey, beeswax and olive oil mixture for atopic dermatitis or psoriasis: partially controlled, single-blinded study

OBJECTIVES

To investigate the effects of honey, olive oil and beeswax mixture on patients with atopic dermatitis (AD) or psoriasis vulgaris (PV).

MATERIALS AND METHODS

Twenty-one patients with dermatitis and 18 patients with psoriasis were entered for patient-blinded, partially controlled study; 11 patients with dermatitis used topical betamethasone esters and 10 patients with psoriasis used clobetasol propionate. Honey mixture contained honey, beeswax and olive oil (1:1:1). Mixtures A, B, and C contained honey mixture with the corticosteroids ointment in a ratio of 1:1, 2:1, and 3:1 respectively. Patients with dermatitis were subjected to controlled bilateral half-body comparison to evaluate the efficacy of honey mixture against Vaseline, or mixture A against Vaseline-betamethasone esters mixture (1:1) in patients using topical corticosteroid treatment. In patients with psoriasis, the effect of honey mixture was compared with paraffin in an individual right/left-sites comparison, or mixture A against paraffin-clobetasol propionate mixture (1:1) in patients using corticosteroid topical therapy. In dermatitis, body lesions on right or left half-body were assessed for erythema, scaling, lichenification, excoriation, indurations, oozing and itching on a 0-4 points scale. In psoriasis, lesions of selected site were assessed for redness, scaling, thickening and itching, on a 0-4 points scale.

RESULTS

In honey mixture group, 8/10 patients with dermatitis showed significant improvement after 2 weeks, and 5/11 patients pretreated with betamethasone esters showed no deterioration upon 75% reduction of corticosteroid doses with use of mixture C. In psoriasis, 5/8 patients showed a significant response to honey mixture. In patients using clobetasol propionate, 5/10 patients showed no deterioration upon 75% reduction of corticosteroid doses with use of mixture C.

CONCLUSION

Honey mixture appears useful in the management of dermatitis and psoriasis vulgaris.

Perioperative administration of parenteral fish oil supplements in a routine clinical setting improves patient outcome after major abdominal surgery

BACKGROUND & AIMS

It is hypothesized that provision of pre- and/or postoperative omega-3 fatty acids to surgical patients in clinical routine improves clinical outcome.

METHODS

Retrospective evaluation of a 2-year-longitudinal data base of ICU patients (n=249) elected for major abdominal surgery. Group I (n=110): postoperative standard parenteral nutrition (1.2 g amino acids, 0.3 g glutamine dipeptide, 0.6 g lipids, 4 g/kg glucose; energy ratio glucose to lipid 2:1); group II (n=86): part of postoperative lipid emulsion replaced by fish oil; group III (n=53): in addition 2-3 days preoperative fish oil supplementation (max. 100 ml/d).

RESULTS

A decrease in mortality was observed in group III compared to group I (P=0.02). The number of patients requiring mechanical ventilation was lower with perioperative fish oil (n=34 in groups I and II. 10 in III, P<0.05). The number of days in ICU was not different (group I: 7.6 days, group II: 7.0, group III: 7.3), the length of hospital stay was shorter in group I (group I: 29.2 days, group II: 24.9, group III: 22.2, P<0.05 vs I).

CONCLUSIONS

In a retrospective evaluation, perioperative provision of parenteral fish oil (ca. 10 g/day) beneficially influences patient outcome probably by modulating the immune response.

The role of fish oils in the treatment of rheumatoid arthritis

Fish oils are a rich source of omega-3 long chain polyunsaturated fatty acids (n-3 LC PUFA). The specific fatty acids, eicosapentaenoic acid and docosahexaenoic acid, are homologues of the n-6 fatty acid, arachidonic acid (AA). This chemistry provides for antagonism by n-3 LC PUFA of AA metabolism to pro-inflammatory and pro-thrombotic n-6 eicosanoids, as well as production of less active n-3 eicosanoids. In addition, n-3 LC PUFA can suppress production of pro-inflammatory cytokines and cartilage degradative enzymes. In accordance with the biochemical effects, beneficial anti-inflammatory effects of dietary fish oils have been demonstrated in randomised, double-blind, placebo-controlled trials in rheumatoid arthritis (RA). Also, fish oils have protective clinical effects in occlusive cardiovascular disease, for which patients with RA are at increased risk. Implementation of the clinical use of anti-inflammatory fish oil doses has been poor. Since fish oils do not provide industry with the opportunities for substantial profit associated with patented prescription items, they have not received the marketing inputs that underpin the adoption of usual pharmacotherapies. Accordingly, many prescribers remain ignorant of their biochemistry, therapeutic effects, formulations, principles of application and complementary dietary modifications. Evidence is presented that increased uptake of this approach can be achieved using bulk fish oils. This approach has been used with good compliance in RA patients. In addition, an index of n-3 nutrition can be used to provide helpful feedback messages to patients and to monitor the attainment of target levels.Collectively, these issues highlight the challenges in advancing the use of fish oil amid the complexities of modern management of RA, with its emphasis on combination chemotherapy applied early.

Effect of arachidonic and eicosapentaenoic acids on acute lung injury induced by hypochlorous acid

BACKGROUND

Hypochlorous acid (HOCl) is the main oxidant of activated polymorphonuclear neutrophil granulocytes (PMN) and generated by myeloperoxidase during respiratory burst. This study investigates the effects of HOCl on pulmonary artery pressure (PAP) and vascular permeability and characterises the influence of arachidonic acid (AA) and eicosapentaenoic acid (EPA) on the observed effects.

METHODS

HOCl (500, 1,000, 2,000 nmol/min) was continuously infused into the perfusate (Krebs-Henseleit buffer solution, KHB). AA or EPA in subthreshold doses (both 2 nmol/min) or buffer were simultaneously infused using a separate port. PAP, pulmonary venous pressure (PVP), ventilation pressure, and lung weight gain were continuously recorded. The capillary filtration coefficient (Kf,c) was calculated before and 30, 60, and 90 minutes after starting the HOCl infusion.

RESULTS

HOCl application resulted in a dose dependent increase in PAP and Kf,c. The onset of these changes was inversely related to the HOCl dose used. The combined infusion of AA with HOCl resulted in a significant additional rise in pressure and oedema formation which forced premature termination of all experiments. The combination of EPA with HOCl did not result in an enhancement of the HOCl induced rise in pressure and oedema formation.

CONCLUSIONS

Changes in the pulmonary microvasculature caused by HOCl are differently influenced by omega-6 and omega-3 polyunsaturated free fatty acids, suggesting a link between neutrophil derived oxidative stress and pulmonary eicosanoid metabolism.

Gene polymorphisms, inflammatory diseases and cancer

Genes whose products play a critical role in regulation of the immune response include the human leucocyte antigen (HLA) and cytokine families of genes. The HLA genes are the most polymorphic found in the human genome, and the bulk of this polymorphism results in functional differences in expressed HLA molecules, resulting in inter-individual differences in presentation of peptide antigens to T-cells. In addition, a considerable number of cytokine-associated gene polymorphisms have been identified, the bulk of which occur in the upstream promoter sequences of these genes, which in many cases results in differential in vitro expression of the respective pro- or anti-inflammatory gene product. Particular HLA polymorphisms result in well-defined associations with a large number of immunologically-mediated diseases, including some diseases with known dietary risk factors. For example, individuals of HLA-DQA1*0501, DQB1*0201 genotype have a greater than 200-fold increased risk of developing intolerance to dietary wheat gluten (coeliac disease), and additional HLA-related factors may influence the development of malignant lymphoma within pre-existing coeliac disease. Similarly, HLA-DRB1 alleles sharing a common sequence motif constitute the primary known genetic risk factor for rheumatoid arthritis. The influence of polymorphisms associated with differential cytokine expression on disease susceptibility is currently of much interest. Most attention has been focused on associations with susceptibility to benign immunologically-mediated diseases, including a number of gut diseases. However, recent work from our laboratory indicates that cytokine polymorphisms may influence susceptibility to and prognosis in a number of different cancers, including malignant melanoma skin cancer and solid tumours which may be influenced by diet, such as prostate cancer (collaboration with the CRC/BPG UK Familial Prostate Cancer study). In addition, preliminary work suggests that dietary modulation of expression levels of certain cytokines in healthy human subjects may be genotype dependent.

The ability of fish oil to suppress tumor necrosis factor alpha production by peripheral blood mononuclear cells in healthy men is associated with polymorphisms in genes that influence tumor necrosis factor alpha production

BACKGROUND

Tumor necrosis factor alpha (TNF-alpha) mediates inflammation. High TNF-alpha production has adverse effects during disease. Polymorphisms in the TNF-alpha and lymphotoxin alpha genes influence TNF-alpha production. Fish oil suppresses TNF-alpha production and has variable antiinflammatory effects on disease.

OBJECTIVE

We examined the relation between TNF-alpha and lymphotoxin alpha genotypes and the ability of dietary fish oil to suppress TNF-alpha production by peripheral blood mononuclear cells (PBMCs) in healthy men.

DESIGN

Polymorphisms in the TNF-alpha (TNF*1 and TNF*2) and lymphotoxin alpha (TNFB*1 and TNFB*2) genes were determined in 111 healthy young men. TNF-alpha production by endotoxin-stimulated PBMCs was measured before and 12 wk after dietary supplementation with fish oil (6 g/d).

RESULTS

Homozygosity for TNFB*2 was 2.5 times more frequent in the highest than in the lowest tertile of inherent TNF-alpha production. The percentage of subjects in whom fish oil suppressed TNF-alpha production was lowest (22%) in the lowest tertile and doubled with each ascending tertile. In the highest and lowest tertiles, mean TNF-alpha production decreased by 43% (P < 0.05) and increased by 160% (P < 0.05), respectively. In the lowest tertile of TNF-alpha production, only TNFB*1/TNFB*2 heterozygous subjects were responsive to the suppressive effect of fish oil. In the middle tertile, this genotype was 6 times more frequent than the other lymphotoxin alpha genotypes among responsive individuals. In the highest tertile, responsiveness to fish oil appeared unrelated to lymphotoxin alpha genotype.

CONCLUSION

The ability of fish oil to decrease TNF-alpha production is influenced by inherent TNF-alpha production and by polymorphisms in the TNF-alpha and lymphotoxin alpha genes.

Eicosapentaenoic acid, a n-3 polyunsaturated fatty acid differentially modulates TNF-alpha, IL-1alpha, IL-6 and PGE2 expression in UVB-irradiated human keratinocytes

In response to UVB-irradiation keratinocytes release a variety of cytokines and prostaglandins, including tumor necrosis factor alpha (TNF-alpha), interleukin 1alpha (IL-1alpha), interleukin 6 (IL-6), and prostaglandin E2 (PGE2). n-3 Polyunsaturated fatty acids (PUFA), mainly present in fish oil, can modulate cytokine synthesis, as predominantly studied in macrophages. In order to investigate the immune modulating actions of n-3 PUFA on the UVB response in human skin, we investigated the effect of eicosapentaenoic acid (EPA), a n-3 PUFA and a precursor of eicosanoid biosynthesis, on UVB-modulated TNF-alpha, IL-1alpha, IL-6, and PGE2 expression in normal human keratinocytes (NHK). We show that cultured NHK can efficiently take up EPA. Basal TNF-alpha expression is very low in NHK. IL-1alpha on the contrary is significantly present in untreated cultured NHK. Upon UVB-irradiation (32 mJ per cm2) TNF-alpha mRNA expression and secretion is induced and IL-1alpha mRNA expression is reduced, although IL-1alpha secretion is induced. EPA treatment results in higher TNF-alpha and IL-1alpha expression, both in nonirradiated and UVB-irradiated keratinocytes. Moreover EPA and UVB appear to act synergistically to superinduce TNF-alpha expression. EPA treatment results also in lipid peroxidation and in decreased PGE2 and IL-6 secretion after UVB-irradiation. In contrast to EPA, oleic acid (monounsaturated fatty acid) and linoleic acid (n-6 PUFA) treatment did not result in higher TNF-alpha or IL-1alpha levels in nonirradiated or UVB-irradiated NHK, indicating that the observed effects are specific for EPA. In conclusion, these results show that EPA can differentially modulate UVB-induced cytokine and prostaglandin synthesis in NHK.

Assessment of omega-fatty-acid-supplemented human platelets for potential improvement in long-term storage

Uptake of omega (omega)-3 fatty acids can influence membrane stability and cell mobility. We investigated the effects of omega-3 and -6 fatty acids on the hemostatic efficacy of human platelets using an in vivo rabbit bleeding model. In vitro assays such as platelet aggregation, vWF bead-mediated ATP release and platelet adhesion to beads (measured by the residual platelet count [RPC] [free platelet count after reacting with the beads]/[baseline platelet count]x 100=%RPC; a high %RPC indicates reduced platelet function) were conducted on platelets treated with 1% fish oil (omega-3); 2% fish oil emulsion or 1% soy oil (omega-6). Oil treatment of platelets reduced the vWF bead-induced ATP release insignificantly. Addition of omega-3 agents reduced physical reactivity (%RPC) with the vWF beads by a factor of 1.2 (oil) and 1.9 (emulsion). The omega-6 oil enhanced reactivity by a factor of 1.7. After washing to remove excess reagent, platelet resuspension was most efficient with the omega-3 emulsion. Platelet function was higher with the omega-3-treated platelets (%RPC=52.3%, omega-3 oil; 63.3%, omega-3 emulsion vs. 85%, omega-6 oil; 82% untreated platelets). Ethyl-palmitate-treated thrombocytopenic rabbits were infused with human platelets. Survival times of the treated platelets, as monitored by flow cytometry (6.2-8.2 h) were comparable to untreated platelets (8.6 h). In the rabbit kidney injury model, blood loss after infusion of the treated platelets was similar to that of saline-infused rabbits (75.3+/-3.4 g). However, platelets washed prior to infusion reduced blood loss to a value comparable to that of fresh platelets (48.3+/-5 g). Furthermore, the presence of the infused platelets at the injury site was clearly visualized using FITC-tagged anti CD42a antibody. Thus, the omega-3-based agents protect the platelets from damage during the washing procedure as demonstrated in vitro by improved platelet resuspension, low %RPC, high stimulus-responsive ATP secretion and a reduction in blood loss in vivo.

n-3 fatty acids in psoriasis

Increased concentrations of free arachidonic acid (AA) and its proinflammatory metabolites have been observed in psoriatic lesions. Replacement of arachidonic acid by alternative precursor polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA), which can be metabolized via the same enzymatic pathways as AA, might be a therapeutic option in psoriasis. However the results of studies evaluating the therapeutic benefit of dietary fish oil have been conflicting and not clearly dose-dependent. To overcome the slow kinetics and limited availability of oral supplementation, we have performed three studies to assess the efficacy and safety of an intravenously administered fish oil derived lipid emulsion on different forms of psoriasis. Patients received daily infusions of either an n-3 fatty acid-based lipid emulsion (Omegaven) or a conventional n-6 lipid emulsion (Lipoven) in different time and dose regimens. In addition to an overall assessment of the clinical course of psoriasis, EPA- and AA-derived neutrophil 5-lipoxygenase (LO)--products, thromboxane (TX) B2/B3, PAF and plasma free fatty acids were investigated. Treatment with n-3 fatty acids resulted in a considerably higher response rate than infusion of n-6 lipids. A more than 10-fold increase in neutrophil EPA-derived 5-LO product formation was noted in the n-3 group, accompanied by a rapid increase in plasma-free EPA within the first days. In conclusion, intravenous n-3-fatty acid administration causes reduction of psoriasis, which may be related to changes in inflammatory eicosanoid generation. The rapidity of the response to intravenous n-3 lipids exceeds by orders of magnitude the hitherto reported kinetics of improvement of psoriatic lesions upon use of oral supplementation.

Coincidence of immune-mediated diseases driven by Th1 and Th2 subsets suggests a common aetiology. A population-based study using computerized general practice data

BACKGROUND

The recent rise in the prevalence of immune-mediated diseases has been attributed to environmental factors such as a lack of microbial challenge, or dietary change, that deviate the overall balance between mutually antagonistic subsets of T helper (Th) cells.

OBJECTIVE

An alternative proposal is that recent environmental changes have resulted in an immune system that is more likely to produce both Th1 and Th2 responses against benign antigens. The prediction of this hypothesis, that Th1 and Th2-mediated diseases are not mutually exclusive, and may be positively associated, is tested here in a whole population.

METHODS

Data from General Practices participating in the Scottish Continuous Morbidity Recording (CMR) project were used to determine the coincidence of the major Th2-mediated atopic diseases; asthma, eczema and allergic rhinitis, with the Th1-mediated autoimmune conditions; type I diabetes, rheumatoid arthritis and psoriasis. We also identified the prescription rates of inhaled therapy for asthma in patients with Th1-mediated disease.

RESULTS

There was a significant increase in the risk of presenting with a Th1-mediated autoimmune condition in patients with a history of allergic disease (standardized prevalence ratio (95% confidence interval) 1.28 (1.18-1.37)). Likewise, the standardized prevalence ratios of presenting with either eczema (1.67 (1.48-1.87)) or allergic rhinitis (1.22 (1.02-1.44)) were significantly increased in subjects with a history of Th1-mediated disease. There was a particularly strong association between current psoriasis and current eczema (standardized prevalence ratio ofpsoriasis in subjects with eczema 2.88, 95% confidence interval (CI) 2.38-3.45). There was also a significant increase in prescriptions for inhaled asthma therapy in patients with Th1 disease.

CONCLUSION

It is concluded that Th1- and Th2-mediated diseases are significantly associated in a large General Practice population. This finding supports the proposal that autoimmune and atopic diseases share risk factors that increase the propensity of the immune system to generate both Th1- and Th2-mediated inappropriate responses to non-pathological antigens.

Clinical use of lipid emulsions

Substantial progress has been made in the understanding of the metabolism of intravenous lipid emulsions and the delivery of their various components to specific tissues or cells. Lipid emulsions should be considered not only as a means of providing energy substrates but also specific compounds that participate in the regulation of key metabolic functions. Such improved knowledge should find applications in the metabolic care of different types of patients.