Crosstalk between skin inflammation and adipose tissue-derived products: pathogenic evidence linking psoriasis to increased adiposity

Psoriasis, Cardiovascular Events, and Biologics: Lights and Shadows

Nowadays, it is well established a link between psoriasis and cardiovascular (CV) diseases. A series of different overlapping mechanisms including inflammation, homeostasis dysregulation, and genetic susceptibility are thought to underlie this association. Advances in understanding the molecular patterns involved in the complex scenario of psoriasis have highlighted a tight correlation with atherosclerosis. Indeed, common profiles are shared in term of inflammatory cytokines and cell types. In the last decade, the management of psoriasis patients has been revolutionized with the introduction of biological therapies, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-12/23, and IL-17 inhibitors. In clinical setting, the effectiveness of these therapies as well as the incidence of CV events is related to the type of biologics. In particular, anti-TNF-α agents seem to reduce these events in psoriasis patients whereas anti-IL-12/23 agents related CV events reduction still remain to clarify. It has to be taken into account that IL-12/23 inhibitors have a shorter post-marketing surveillance period. An even more restricted observational time is available for anti-IL-17 agents. IL-17 is associated with psoriasis, vascular disease, and inflammation. However, IL-17 role in atherosclerosis is still debated, exerting both pro-atherogenic and anti-atherogenic effects depending on the specific context. In this review, we will discuss the differences between the onset of CV events in psoriasis patients, referred to specific biological therapy and the underlying immunological mechanism. Given the development of new therapeutic strategies, the investigation of these inhibitors impact on heart failure outcome is extremely important.

Chemerin: a multifaceted adipokine involved in metabolic disorders

Metabolic syndrome is a global public health problem and predisposes individuals to obesity, diabetes and cardiovascular disease. Although the underlying mechanisms remain to be elucidated, accumulating evidence has uncovered a critical role of adipokines. Chemerin, encoded by the gene Rarres2, is a newly discovered adipokine involved in inflammation, adipogenesis, angiogenesis and energy metabolism. In humans, local and circulating levels of chemerin are positively correlated with BMI and obesity-related biomarkers. In this review, we discuss both peripheral and central roles of chemerin in regulating body metabolism. In general, chemerin is upregulated in obese and diabetic animals. Previous studies by gain or loss of function show an association of chemerin with adipogenesis, glucose homeostasis, food intake and body weight. In the brain, the hypothalamus integrates peripheral afferent signals including adipokines to regulate appetite and energy homeostasis. Chemerin increases food intake in seasonal animals by acting on hypothalamic stem cells, the tanycytes. In peripheral tissues, chemerin increases cell expansion, inflammation and angiogenesis in adipose tissue, collectively resulting in adiposity. While chemerin signalling enhances insulin secretion from pancreatic islets, contradictory results have been reported on how chemerin links to obesity and insulin resistance. Given the association of chemerin with obesity comorbidities in humans, advances in translational research targeting chemerin are expected to mitigate metabolic disorders. Together, the exciting findings gathered in the last decade clearly indicate a crucial multifaceted role for chemerin in the regulation of energy balance, making it a promising candidate for urgently needed pharmacological treatment strategies for obesity.

Adipochemokines induced by ultraviolet irradiation contribute to impaired fat metabolism in subcutaneous fat cells

BACKGROUND

Adipose tissue is now appreciated as the pivotal regulator of metabolic and endocrine functions. Subcutaneous (SC) fat, in contrast to visceral fat, may protect against metabolic syndrome and systemic inflammation. We demonstrated that chronic as well as acute ultraviolet (UV) irradiation to the skin induces loss of underlying SC fat. UV-irradiated SC fat may produce chemokines or cytokines that modulate lipid homeostasis and secretion of adipokines.

OBJECTIVES

To elucidate UV-induced specific adipochemokines implicated in UV-induced modulation of SC fat.

METHODS

Primary cultured adipocytes were treated with conditioned medium from UV- or sham-irradiated skin cells. Young and older healthy participants provided SC fat from sun-exposed and sun-protected skin. Sun-protected skin from other participants was irradiated with UV. Differentially expressed adipochemokines were screened by cytokine array, and confirmed in vitro and in vivo. The functions of select adipochemokines involved in lipid metabolism were examined via short interfering RNA-mediated knockdown of cognate receptors.

RESULTS

Specific adipochemokines, including C-X-C motif chemokine (CXCL) family members such as CXCL5/ENA-78, and C-C motif chemokine (CCL) family members such as CCL20/MIP-3α and CCL5/RANTES, were greatly induced in SC fat by UV exposure. They could impair triglyceride synthesis via downregulation of lipogenic enzymes and sterol regulatory element-binding protein-1 through their respective cognate receptors, CXC chemokine receptor type (CXC-R)2, C-C chemokine receptor type (CCR)-6, and CCR-5. In addition, UV irradiation induced infiltration of adipose tissue macrophages responsible for the secretion of several chemokines into SC fat.

CONCLUSIONS

These UV-induced adipochemokines may be implicated in the reduction of lipogenesis in SC fat, leading to impairment of fat homeostasis and associated comorbidities such as obesity.

[Acne inversa/hidradenitis suppurativa: An update]

Acne inversa (AI)/hidradenitis suppurativa is a chronic, recurrent, immune-mediated dermatosis characterized by deep inflammatory nodules, abscesses, fistulas, and undermined scars in skin areas bearing apocrine glands. In addition to the cutaneous manifestation, numerous AI patients show metabolic changes, spondyloarthritis, and depression. AI leads to a strong reduction in the quality of life and an impairment of the sexual life of affected individuals and often culminates in social withdrawal, stigmatization, unemployment, and suicidal thoughts. In this overview, we summarized the most important facts about AI and propose a simple algorithm for therapy.

The impact of biologic agents on health-related quality of life outcomes in patients with psoriasis

INTRODUCTION

Psoriasis is a common, immune-mediated skin disease often associated with significant physical and psychosocial impairment. Antipsoriatic biologic agents offer patients unparalleled treatment potential in regard to greater skin clearance and overall improved quality of life. Evaluation of the therapeutic efficacy of biologic agents on the full psoriasis disease burden must account for their impact on both physical symptoms, as well as patient-reported, health-related quality of life (HRQoL) measurements. Areas covered: Results from numerous clinical trials demonstrate the significant clinical efficacy of biological agents targeting tumor necrosis factor-α (TNF-α) and the interleukin (IL)-12/23 and IL-17 immune pathways. However, relatively limited data is available evaluating their full effect on quality of life outcomes. This review will discuss the most relevant and up-to-date clinical data on HRQoL measurements related to treatment with these aforementioned biologic agents. Expert commentary: Patient-reported outcomes (i.e. Dermatology Life Quality Index) are being used with increasing frequency in clinical trials, and provide valuable information on the impact of psoriasis on numerous aspects of day-to-day living. These outcomes must also be incorporated in clinical practice, in addition to physical assessment of disease severity, treatment decisions, and therapeutic response in the psoriasis patient population.

Psoriasis and Cardiovascular Comorbidities: Focusing on Severe Vascular Events, Cardiovascular Risk Factors and Implications for Treatment

Psoriasis is a common and chronic inflammatory disease of the skin. It may impair the physical and psychosocial function of patients and lead to decreased quality of life. Traditionally, psoriasis has been regarded as a disease affecting only the skin and joints. More recently, studies have shown that psoriasis is a systemic inflammatory disorder which can be associated with various comorbidities. In particular, psoriasis is associated with an increased risk of developing severe vascular events such as myocardial infarction and stroke. In addition, the prevalence rates of cardiovascular risk factors are increased, including hypertension, diabetes mellitus, dyslipidemia, obesity, and metabolic syndrome. Consequently, mortality rates have been found to be increased and life expectancy decreased in patients with psoriasis, as compared to the general population. Various studies have also shown that systemic treatments for psoriasis, including methotrexate and tumor necrosis factor-α inhibitors, may significantly decrease cardiovascular risk. Mechanistically, the presence of common inflammatory pathways, secretion of adipokines, insulin resistance, angiogenesis, oxidative stress, microparticles, and hypercoagulability may explain the association between psoriasis and cardiometabolic disorders. In this article, we review the evidence regarding the association between psoriasis and cardiovascular comorbidities, focusing on severe vascular events, cardiovascular risk factors and implications for treatment.

Historical perspectives of the metabolic syndrome

The metabolic syndrome (MetS) or insulin resistance syndrome is a constellation of obesity-related metabolic derangements predisposing to type 2 diabetes and cardiovascular disease. In 1998, WHO defined the first criteria of MetS. Three years later, the user-friendly National Cholesterol Education Program criteria of MetS were proposed. Different criteria were issued by the International Diabetes Federation in 2005, making abdominal obesity a necessary component. Several international societies, including The International Diabetes Federation, jointly adopted the revised National Cholesterol Education Program criteria as harmonizing criteria of MetS in 2009. WHO warned the next year that MetS has limited practical utility as a management tool. Adipose tissue inflammation has been shown to be a fundamental mechanism of metabolic derangements, associated with ectopic lipid deposit and mitochondrial dysfunction in skeletal muscle and the liver.

Biologics that inhibit the Th17 pathway and related cytokines to treat inflammatory disorders

INTRODUCTION

Advances in the understanding of TNF-α and IL-17 synergistic functions have recently led to the concept that patients who do not respond or who respond inadequately to TNF-α inhibitors may have IL-17-driven diseases, opening up the way for a new class of therapeutic development: Th17-inhibitors. Areas covered: In this review, the authors discuss the central role that the IL-23/Th17 axis plays in the pathogenesis of several inflammatory diseases, such as psoriasis, highlighting its position as a relevant therapeutic target. In particular, the authors start by giving a brief historical excursus on biologic agent development up until the success of TNF-α inhibitors, and continue with an overview of IL12/23 pathway inhibition. Next, they describe Th17 cell biology, focusing on the role of IL-17 in host defense and in human immune-inflammatory diseases, discussing the use and side effects of IL-17 inhibitors. Expert opinion: The IL-23/Th17 signaling pathway plays a central role in the pathogenesis of several inflammatory diseases, such as psoriasis. Recent data has demonstrated that biologics neutralizing IL-17 (ixekizumab, secukinumab) or its receptor (brodalumab) are highly effective with a positive safety profile in treating moderate to severe psoriasis, offering new treatment possibilities, especially for patients who do not respond adequately to anti-TNF-α therapies.

Obesity, Waist Circumference, Weight Change, and Risk of Incident Psoriasis: Prospective Data from the HUNT Study

Although psoriasis has been associated with obesity, there are few prospective studies with objective measures. We prospectively examined the effect of body mass index, waist circumference, waist-hip ratio, and 10-year weight change on the risk of developing psoriasis among 33,734 people in the population-based Nord-Trøndelag Health Study (i.e., HUNT), Norway. During follow-up, 369 incident psoriasis cases occurred. Relative risk (RR) of psoriasis was estimated by Cox regression. One standard deviation higher body mass index, waist circumference, and waist-hip ratio gave RRs of 1.22 (95% confidence interval [CI] = 1.11-1.34), 1.26 (95% CI = 1.15-1.39), and 1.18 (95% CI = 1.07-1.31), respectively. Compared with normal weight participants, obese people had an RR of 1.87 (95% CI = 1.38-2.52), whereas comparing the fourth with the first quartile of waist circumference gave an RR of 1.95 (95% CI = 1.46-2.61). One standard deviation higher weight change gave an RR of 1.20 (95% CI = 1.07-1.35), and people who increased their body weight by 10 kg or more had an RR of 1.72 (95% CI = 1.15-2.58) compared with being weight stable. In conclusion, obesity and high abdominal fat mass doubles the risk of psoriasis, and long-term weight gain substantially increases psoriasis risk. Preventing weight gain and promoting maintenance of a normal body weight could reduce incidence of psoriasis.

Serum fatty acid profile in psoriasis and its comorbidity

Psoriasis is a chronic inflammatory skin disease that is accompanied by metabolic disturbances and cardio-metabolic disorders. Fatty acids (FAs) might be a link between psoriasis and its comorbidity. The aim of the study was to evaluate serum concentrations of FAs and to investigate their association with the disease activity, markers of inflammation and possible involvement in psoriatic comorbidity: obesity, type 2 diabetes and hypertension. We measured 14 total serum fatty acids content and composition by gas-liquid chromatography and flame-ionization detector after direct in situ transesterification in 85 patients with exacerbated plaque psoriasis and in 32 healthy controls. FAs were grouped according to their biologic properties to saturated FA (SFA), unsaturated FA (UFA), monounsaturated FA (MUFA), n-3 polyunsaturated FA (n-3 PUFA) and n-6 PUFA. Generally, patients characteristic included: Psoriasis Area and Severity Index (PASI), Body Mass Index, inflammatory and biochemical markers, lipid profile and presence of psoriatic comorbidity. We have observed highly abnormal FAs pattern in psoriatic patients both with and without obesity compared to the control group. We have demonstrated association of PASI with low levels of circulating DHA, n-3 PUFA (p = 0.044 and p = 0.048, respectively) and high percent of MUFA (p = 0.024) in the non-obese psoriatic group. The SFA/UFA ratio increased with the duration of the disease (p = 0.03) in all psoriatic patients. These findings indicate abnormal FAs profile in psoriasis which may reflect metabolic disturbances and might play a role in the psoriatic comorbidity.

Hypodermal Adipose Tissue Sonoelastography for Monitoring Treatment Response in Patients with Plaque Psoriasis

BACKGROUND

Psoriasis (PsO) is a multifactorial chronic and relapsing skin disease that affects about 125 million people in the world. Several studies have demonstrated the link between adipose tissue, inflammation, and PsO. The purpose of our study is to evaluate hypodermal adipose tissue inflammation underneath PsO plaques quantifying tissue elasticity with sonoelastography before and after treatment. The study was conducted at the Department of Dermatology of the University of "Rome Tor Vergata" and Department of Radiology of the University of "Rome Tor Vergata."

METHODS

We enrolled 60 patients with plaque PsO and a PASI score of ≥5 divided in three groups of treatment: biologic drugs therapy (Group A), systemic therapy with DMARDS (Group B), and topic therapy (Group C). Each Patient underwent sonoelastography examination (TE: transient elastography) at baseline (T0) and after 1 month (T1) of treatment. The region of interest (ROI) 5 × 5 mm area and the strain ratio was obtained dividing muscular elasticity (referral tissue) by hypodermal elasticity.

RESULTS

The difference between T0 and T1 was referred as Δ strain. Sonoelastography is able to identify hypodermal adipose tissue involvement in plaque PsO and on the basis of our experience it could represent a valid method to assess early therapy response in patient with plaque PsO.

CONCLUSIONS

This is the first report regarding the use of sonoelastography in psoriatic patients. Sonoelastography is easy to use, rapid, and is a portable technique that does not use ionizing radiation. The result showed the mean lesional strain ratio significantly higher than the nonlesional one at baseline examination. In the future, the role of ultrasound sonoelastography is likely to be complementary to conventional imaging techniques in providing an additional tool.

Metabolic Syndrome and Selective Inflammatory Markers in Psoriatic Patients

The presented article studies the role of selected inflammatory and anti-inflammatory serum markers of psoriatic patients in the pathogenesis of metabolic syndrome (MS) and psoriasis. The study is based on the comparison between the group of psoriatic patients (74) and the control group (65). We found significantly higher BMI (p < 0.05) and diastolic blood pressure (p < 0.05) in the psoriatic patients. The values of waist circumference and BMI were significantly higher (p < 0.05) in the male patients compared to the men in the control group. The analysis revealed significantly higher CRP (p < 0.001), Lp-PLA2 (p < 0.001), leptin (p < 0.01), and resistin (p < 0.01) levels in the psoriatic patients. Significantly higher levels of CRP (p < 0.01), Lp-PLA2 (p < 0.001), leptin (p < 0.01), and resistin (p < 0.05) were found in the patients with MS compared to the controls with MS. The level of adiponectin was significantly lower (p < 0.01) in the patients with MS. Finally, we found significantly higher level of Lp-PLA2 (p < 0.001) in the group of patients without MS compared to the controls without MS. In conclusion, observed inflammatory and anti-inflammatory markers (CRP, adiponectin, leptin, resistin, and Lp-PLA2) are involved in both pathogenesis of MS and pathogenesis of psoriasis. The level of Lp-PLA2 indicates the presence of subclinical atherosclerosis (cardiovascular risk) in psoriatic patients.

Increase in circulating sphingosine-1-phosphate and decrease in ceramide levels in psoriatic patients

Psoriasis is characterized by hyperproliferation, deregulated differentiation and impaired apoptosis of keratinocytes. Mechanisms of lipid profile disturbances and metabolic syndrome in the psoriatic patients are still not fully understood. Sphingolipids, namely ceramides (CER) and sphingosine-1-phosphate (S1P) are signal molecules which can regulate cell growth, apoptosis and immune reactions. The aim of the study was to evaluate circulating CER and S1P levels in plaque-type psoriasis and their associations with the disease activity, inflammatory or metabolic markers and the presence of psoriatic comorbidities. Eighty-five patients with exacerbated plaque-type psoriasis and thirty-two healthy controls were enrolled. Serum CER and S1P concentrations before the treatment were examined. General patient characteristics included: PASI (Psoriasis Area and Severity Index), BMI (Body Mass Index), inflammatory and biochemical markers, lipid profile and presence of psoriatic comorbidities. Total serum concentration of CER was significantly decreased (p = 0.02) and concomitantly S1P levels significantly increased (p = 0.002) in psoriatic patients compared to the healthy control group. Among patients with psoriasis no significant correlations with the disease activity and inflammation markers were observed and only patients with psoriatic arthritis had significantly higher CER total concentration. Serum sphingolipid disturbances in psoriatic patients were observed. Decreased total CER and increased S1P serum levels may reflect their epidermal altered composition and metabolism. Patients with psoriatic arthritis have higher CER levels than psoriasis with skin involvement only. It might provide additional predictive value for psoriatic arthritis and may convey higher risk of metabolic and cardiovascular disease development in this group of patients.

Serum irisin levels in patients with psoriasis

BACKGROUND

Irisin has been proposed to regulate metabolic diseases such as obesity, diabetes or metabolic syndrome which are common comorbidities in psoriasis.

OBJECTIVES

The aim of this study was to evaluate the serum irisin level in psoriasis and elucidate possible associations with disease activity, inflammatory or metabolic parameters and topical treatment.

METHODS

Thirty-seven individuals with active plaque-type psoriasis and 15 healthy controls were enrolled. Blood samples were collected before and after two weeks of therapy. Serum irisin concentrations were examined by enzyme-linked immunosorbent assay (ELISA). The results were correlated with psoriasis area and severity index (PASI), body mass index (BMI), inflammatory and biochemical markers, lipid profile and effectiveness of topical treatment.

RESULTS

Irisin serum levels were insignificantly increased in psoriatic patients in comparison to the controls (p = 0.38). No significant correlations between investigated adipokine and several indicators of metabolic disorders, nor BMI (p = 0.37) or PASI (p = 0.5) were found. Significant positive correlations with C-reactive protein (CRP) (0.009), lipocalin-2 (p = 0.02), age (p = 0.02) and disease duration (p = 0.008) were noted. After topical treatment, serum irisin level did not significantly change (p = 0.31), despite clinical improvement.

CONCLUSIONS

Irisin might be a marker of inflammation in psoriatic patients, but may not be a reliable indicator of metabolic conditions, severity of psoriasis nor efficacy of antipsoriatic treatment.