The fatty-acid spectrum in plasma and adipose tissue in patients with psoriasis

The causal relationship between serum metabolites and the risk of psoriasis: a Mendelian randomization and meta-analysis study

Objective

To explore the influence of serum metabolites on the risk of psoriasis.

Methods

In the initial stage, we applied Mendelian randomization to evaluate the association between 1,400 serum metabolites and the risk of psoriasis. Causal effects were primarily assessed through the Inverse-Variance Weighted method and Wald Ratio's odds ratios, and 95% confidence intervals. False Discovery Rate was used for multiple comparison corrections. Sensitivity analyses were conducted using Cochran's Q Test, MR-PRESSO. MR-Steiger Test was employed to check for reverse causality. In the validation stage, we sought other sources of psoriasis GWAS data to verify the initial results and used meta-analysis to combine the effect sizes to obtain robust causal relationships. In addition, we also conducted metabolic pathway enrichment analysis on known metabolites that have a causal relationship with the risk of psoriasis in both stages.

Results

In the initial stage, we identified 112 metabolites causally associated with psoriasis, including 32 metabolite ratios and 80 metabolites (69 known and 11 unknown). In the validation stage, 24 metabolites (16 known, 1 unknown, and 7 metabolite ratios) were confirmed to have a causal relationship with psoriasis onset. Meta-analysis results showed that the overall effect of combined metabolites was consistent with the main analysis in direction and robust in the causal relationship with psoriasis onset. Of the 16 known metabolites, most were attributed to lipid metabolism, with 5 as risk factors and 8 as protective factors for psoriasis. Peptidic metabolite Gamma-glutamylvaline levels had a negative causal relationship with psoriasis, while exogenous metabolite Catechol sulfate levels and amino acid 3-methylglutaconate levels had a positive causal relationship with the disease onset. The metabolites associated with psoriasis risk in the two stages are mainly enriched in the following metabolic pathways: Glutathione metabolism, Alpha Linolenic Acid and Linoleic Acid Metabolism, Biosynthesis of unsaturated fatty acids, Arachidonic acid metabolism, Glycerophospholipid metabolism.

Conclusion

Circulating metabolites may have a potential causal relationship with psoriasis risk, and targeting specific metabolites may benefit psoriasis diagnosis, disease assessment, and treatment.

Obesity and dyslipidemia in patients with psoriasis: A case-control study

The aim of this study was to conduct a more comprehensive analysis of the association between psoriasis and abnormal lipid metabolism.The case-control study included 222 psoriatic patients and 445 non-psoriatic control patients matched for age and gender. Clinical parameters included age, gender, and body mass index (BMI). Serum lipid levels were recorded and included cholesterol (CHO), triglycerides (TG), low-density lipoprotein (LDL), high density lipoprotein (HDL), phospholipids (PLIP), free fatty acids (FFA), lipoprotein (a) [Lp(a)], and apolipoproteins (apoA1, apoB, and apoE). Statistical analysis was carried out through the IBM Statistical Package for the Social Studies version 23.0.Compared with controls, levels of BMI and the prevalence of obesity were significantly higher in psoriatic patients. The results revealed that when compared to controls, significant elevation of serum TG (P <.001) and Lp(a) (P = .022) was observed. Levels of HDL (P <.001) and apoA1 (P <.001) were significantly lower in psoriatic patients. There was no significant difference in CHO (P = .367), LDL (P = .400), apoB (P = .294), apoE (P = .05), PLIP (P = .931) and FFA (P = .554) between patients and controls. The levels of CHO, TG, PLIP, FFA, and apoE were positively correlated with BMI level.Dyslipidemia was more common in psoriatic patients, compared with non-psoriatic controls.

Plasma Phospholipid Fatty Acid Content Is Related to Disease Activity in Ankylosing Spondylitis

Objective.

To investigate fatty acid composition in the diet, plasma phospholipids, and adipose tissue in a cohort of patients with ankylosing spondylitis (AS), and to determine their correlations to disease activity and blood lipids in a cross-sectional study.

Methods.

Diet was assessed using a food frequency questionnaire in 66 patients with AS. Polyunsaturated fatty acids in plasma phospholipids and gluteal adipose tissue were measured using gas chromatography. Disease status was quantified using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein, and proinflammatory cytokines.

Results.

Diet did not correlate with disease activity assessed by the BASDAI, but there were negative correlations between the dietary intake of long-chain omega-3 fatty acids and ESR (rs = –0.27, p < 0.05). The plasma phospholipid content of arachidonic acid correlated significantly with the BASDAI score (rs = 0.39, p < 0.01). There were correlations between the intake of long-chain omega-3 fatty acids and high-density lipoproteins and serum triglycerides (rs = 0.26 and rs = –0.25, respectively, p < 0.05).

Conclusion.

There was a positive correlation between levels of arachidonic acid in plasma phospholipids and disease activity assessed by BASDAI in patients with AS. A Western diet does not appear to influence this correlation, but seems to affect blood lipids involved in atherogenic processes.

Lipid disturbances in psoriasis: an update

Psoriasis is a common disease with the population prevalence ranging from 2% to 3%. Its prevalence in the population is affected by genetic, environmental, viral, infectious, immunological, biochemical, endocrinological, and psychological factors, as well as alcohol and drug abuse. In the recent years, psoriasis has been recognised as a systemic disease associated with numerous multiorgan abnormalities and complications. Dyslipidemia is one of comorbidities in psoriatic patients. Lipid metabolism studies in psoriasis have been started at the beginning of the 20th century and are concentrated on skin surface lipids, stratum corneum lipids and epidermal phospholipids, serum lipids, dermal low-density lipoproteins in the psoriatic skin, lipid metabolism, oxidative stress and correlations between inflammatory parameters, lipid parameters and clinical symptoms of the disease. On the basis of the literature data, psoriasis can be described as an immunometabolic disease.

Serum lipids and apolipoproteins in patients with psoriasis

Psoriasis is characterized by defects in the normal cycle of epidermal development that lead to epidermal hyperproliferation, altered maturation of skin cells, vascular changes and inflammation. Also, psoriasis has been associated with an abnormal plasma lipid metabolism. Changes in plasma lipid and lipoprotein composition in patients with psoriasis may be the reason for the increased risk of atherosclerosis in these patients. We determined serum concentrations of lipids, lipoproteins and apolipoprotein Al and B (apo A1 and apo B) in 72 patients with psoriasis and 30 age matched controls. Serum lipoprotein (a) (Lp(a)), apo A1 and apo B were measured by immunoprecipitation assays, and the lipids and other biochemical parameters by enzymatic methods. Serum Lp(a) and triglyceride (TG) were significantly higher in patients with psoriasis than in healthy control subjects (p<0.01 for both). Apo B was also found to be higher in the patient group, but the difference was not significant. The levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and apo A1 did not differ significantly from those of the controls. These observations imply that serum Lp(a) and TG concentrations may play a role as risk factors for atherosclerotic disease in patients with psoriasis.

Essential fatty acid deficiency in renal failure: can supplements really help?

Abnormal fatty acid metabolism may contribute to clinical problems such as itching, abnormal perspiration, susceptibility to infection, delayed wound healing, anemia, and increased hemolysis, as seen in patients with chronic renal failure. A double-blind study of patients on hemodialysis who received either fish oil, olive oil, or safflower oil documented that patients may have increased levels of the proinflammatory prostaglandin PGE2 and that fish oil intervention may decrease these levels, change the fatty acid profile, improve hematocrit levels, and improve patient perception of symptoms of pruritus.

Evening primrose oil and marine oil in the treatment of psoriasis

The effect of dietary supplementation with a combination of n-3 (marine oil) and n-6 (evening primrose oil) essential fatty acids in the treatment of chronic stable plaque psoriasis was observed. Thirty-seven patients in a double-blind parallel trial were studied. There was no significant improvement in clinical severity of psoriasis or change in transepidermal water loss.

Adipose hormone-sensitive lipase preferentially releases polyunsaturated fatty acids from triglycerides

Rat adipose hormone-sensitive lipase-mediated release of fatty acids from triglycerides was studied in three model systems: i) cultured preadipocytes containing polyunsaturated fatty acid-enriched triglyceride; ii) perfused epididymal fat pads; and iii) in vitro incubations of crude preparations of hormone-sensitive lipase with synthetic triglyceride-analogues as substrates. We found that cultured preadipocytes challenged with 10 microM norepinephrine tended to release more omega 6 and omega 3 polyunsaturated fatty acids than saturated fatty acids. Fat pads perfused with 10 microM norepinephrine preferentially released arachidonate and alpha-linolenate but tended to retain oleate and linoleate. Finally, crude preparations of hormone-sensitive lipase released from the triglyceride-analogue substrates alpha-linolenate twice as fast as oleate. We conclude that rat adipose hormone-sensitive lipase preferentially releases polyunsaturated fatty acids from triglycerides. We suggest that this may be a mechanism by which these fatty acids are kept from being trapped in fat depots and maintained in the circulation.

Modulation of polyunsaturated fatty acid content of triglycerides in rat pre-adipocytes in culture

Rat peri-renal and epididymal pre-adipocytes in culture undergoing triglyceride (TG) accumulation were incubated with oleic (18:1), linoleic (18:2), alpha-linolenic (18:3 omega 3), arachidonic (20:4) and 4,7,10,13,16,19-docosahexaenoic (22:6 omega 3) acids in the presence of 0.8 microM insulin. The fatty acids were incorporated in cellular TG with relative enrichments over control from 1.4-fold for 18:1 to greater than 40-fold for 18:3 omega 3. Greater than 80% of fatty acids taken up were incorporated into cellular TG. The balance was distributed, in decreasing amounts, into phospholipids, unidentified intracellular constituents, and ketone bodies. The P/S ratio of cellular TG was at least an order of magnitude lower than that of the external milieu for both cell types and for all treatment groups, including controls. Doubling the concentration of treatment fatty acid increased its incorporation into cellular TG. However, it did not affect the accumulation of the other fatty acids in TG. Epididymal cells consistently acquire a higher proportion of treatment fatty acids in cell TG than peri-renal cells. Pre-adipocytes with polyunsaturated fatty acids (PUFA)-enriched TG is a potential model for the study of PUFA metabolism in these types of cells.

Essential-fatty-acid metabolites in plasma phospholipids in patients with ichthyosis vulgaris, acne vulgaris and psoriasis

The concentration of essential fatty acids (EFAs) and their metabolites in plasma phospholipids were measured by gas chromatography in normal individuals, and in patients with ichthyosis vulgaris, acne vulgaris or psoriasis. In all three patient groups, concentrations of arachidonic acid (20:4 omega 6) and docosapentaenoic acid (22:5 omega 6) were significantly below those in controls, suggesting that these abnormalities may occur in many skin diseases. Concentrations of dihomogammalinolenic acid (20:3 omega 6) were low in ichthyosis, normal in acne and elevated in psoriasis. Thus ichthyosis, acne and psoriasis each had a characteristic pattern of EFA metabolites.

Transmembrane cation fluxes and fatty acid composition of erythrocytes in psoriatic patients

Cation transport systems and lipid composition of erythrocyte membrane were studied in 27 psoriatic patients and in 34 healthy individuals. Whereas intracellular Na and K content, Na- and K-passive permeability and Li-Na countertransport of psoriatics did not show any statistical difference from normals, the Na/K ATPase pump activity was significantly higher and Na-K cotransport was significantly lower. Membrane lipid composition of psoriatics was different from normals: an increase in arachidonic acid and in unsaturated (poly- and total unsaturated) fatty acid content was found. A positive correlation was demonstrated between unsaturated/saturated fatty acid ratio and Na/K ATPase pump activity. These results demonstrate an alteration of erythrocyte Na/K ATPase pump and Na-K cotransport in psoriasis. These alterations of cation transport are associated with a perturbation of membrane fatty acid composition which appears a widespread phenomenon in cells of psoriatic patients.

Essential fatty acids in clinical dermatology

A deficiency of essential fatty acid intake can produce severe cutaneous abnormalities but is exceedingly rare in clinical practice. Recent research has shown that abnormalities in essential fatty acid metabolism may play a role in atopic eczema, acne, and psoriasis. Therapeutic innovations have already resulted from this knowledge, and more are likely to emerge.

Fish oil supplementation results in decreased hypertriglyceridemia in patients with psoriasis undergoing etretinate or acitretin therapy

Although retinoid derivatives are an effective treatment for severe psoriasis, they result in systemic toxicity, including hyperlipidemia. In an attempt to reverse this retinoid-related hyperlipidemia in patients with psoriasis, a prospective 4-week pilot study of fish oil supplementation was carried out in 25 patients with psoriasis vulgaris receiving etretinate (Ro-10-9359) or acitretin (Ro 10-1670). Daily fish oil supplements containing 3 gm of omega-3 fatty acids (1.8 gm of eicosapentaenoic acid 20:5 omega 3, and 1.2 gm of docosahexaenoic acid 22:6 omega 3) were found to be effective in reducing hypertriglyceridemia, with a significant mean reduction from 215.6 +/- 92.5 to 156.9 +/- 58.5 mg/dl (-27%) when compared with controls (203.6 +/- 46.9 to 204.1 +/- 54.3 mg/dl). High-density lipoprotein cholesterol levels increased from 41.4 +/- 10.5 to 46.1 +/- 10.8 mg/dl (+11%), and the ratio of total cholesterol to high-density lipoprotein cholesterol decreased from 6.6 +/- 1.9 to 5.9 +/- 1.7 (-11%). It is concluded that fish oil supplementation may prove a valuable adjunct to ameliorate the lipid changes secondary to retinoids.