Adipocytokines and psoriasis: Insights into mechanisms linking obesity and inflammation to psoriasis

Deciphering the Association Between Psoriasis and Obesity: Current Evidence and Treatment Considerations

PURPOSE OF REVIEW

Obesity and psoriasis represent chronic inflammatory states that are interconnected in a vicious cycle, sharing also a degree of synergy. In this review, we aim to decipher the various lines of evidence supporting the bidirectional association between psoriasis and obesity highlighting their pathophysiologic connections as well as we attempt to strategize a therapeutic holistic approach for obese psoriatic patients.

RECENT FINDINGS

Recent meta-analyses have shown that (1) genetically higher BMI increased the odds of psoriasis occurrence; (2) obesity is associated with higher incidence and prevalence of psoriasis as well as psoriasis severity; (3) obesity is associated with lower efficacy to anti-TNF agents and may predict biologic treatment discontinuation; and (4) weight loss through diet and physical exercise may improve pre-existing psoriasis and prevent from de novo psoriasis. Methotrexate, acitretin, and cyclosporine could worsen hypertension, liver steatosis, and dyslipidemia. Since infliximab and ustekinumab are weight adjusted, they may be ideal drugs to treat obese psoriatic patients. IL-17 inhibitors are very effective independently from body weight; however, they tend to present better clearance rates in normal weight patients. There is a paucity on weight data regarding the efficacious IL-23 inhibitors. Apremilast may induce weight loss as an adverse effect presenting also some beneficial metabolic actions. Finally, simvastatin and some antidiabetic drugs could decrease psoriasis severity. More mechanistic, observational studies and well-conducted RCTs are necessary to decipher the enigmatic link between psoriasis and obesity, and to provide evidence-based specific guidelines for the screening and management of obese psoriatic patients.

Psoriasis is associated with risk of obstructive sleep apnea independently from metabolic parameters and other comorbidities: a large hospital-based case-control study

PURPOSE

Obstructive sleep apnea (OSA) represents a breathing disorder during sleep with significant health consequences. Few studies have examined the prevalence of OSA in psoriatic patients and whether OSA may be associated with psoriasis risk. We aimed to explore: (1) the inverse relationship, that is whether psoriasis might represent an independent predictor of OSA and its severity considering important predisposing factors and (2) the psoriatic phenotype related to severe OSA.

METHODS

In a large hospital-based case-control study, we examined a total of 253 patients with OSA and a control group of 104 subjects without OSA, who underwent full nocturnal polysomnography and dermatologic examination.

RESULTS

The prevalence of psoriasis was significantly greater in OSA patients than in controls (p = 0.03). Psoriasis was associated with OSA risk (p = 0.04) but not severity of OSA, sleepiness severity or sleep efficiency, independently from age, gender, anthropometric features, and significant comorbidities. The phenotype of a psoriatic patient suffering from severe OSA is not different from that of a patient with severe OSA and is not associated with psoriasis severity indexes. OSA psoriatic patients were not compliant with CPAP treatment in comparison with OSA patients without psoriasis.

CONCLUSION

Psoriasis may represent an independent risk factor for OSA above and beyond significant comorbidities, anthropometric and metabolic parameters. Physicians should be aware of the bi-directional association of psoriasis and OSA. Managing psoriasis may be a potential target for preventing OSA as well as the potential cardiovascular mortality related to OSA and psoriasis.

Effect of inhibition of interleukin-12/23 by ustekinumab on the expression of leptin and leptin receptor in human THP-1 macrophages

BACKGROUND

Leptin, an adipocyte-derived circulating cytokine that signals nutritional status, may play a role in the development of psoriasis and its associated systemic diseases. Patients with psoriasis have significantly decreased serum leptin levels compared with controls.

AIM

To investigate the effect of two commonly used anti-psoriatic biologic drugs, adalimumab and ustekinumab, on leptin and leptin receptor expression in human macrophages.

METHODS

THP-1 differentiated macrophages were cultured under the following conditions: (i) untreated control, (ii) adalimumab 5 μg/mL, (iii) ustekinumab 1 μg/mL and (iv) ustekinumab 5 μg/mL. Expression of leptin and leptin receptors were measured using real-time quantitative PCR and immunoblotting techniques.

RESULTS

The presence of either adalimumab or ustekinumab in growth medium significantly upregulated expression of leptin receptor in THP-1 human macrophages to 1.98 ± 0.47 and 2.09 ± 0.24, respectively (n = 3, P < 0.01) vs. 1.12 ± 0.19 for untreated control cells. However, only ustekinumab at a concentration of 5 μg/mL augmented expression of leptin to 1.99 ± 0.56 (n = 3, P < 0.01) vs. control untreated cells.

CONCLUSIONS

Enhanced leptin and leptin receptor expression in macrophages exposed to therapeutic levels of ustekinumab suggest a novel immunomodulatory mechanism for this biologic drug. Further mechanistic studies may yield targeted treatment using the leptin pathway, which could reduce the common obesity-related complications of psoriasis while alleviating symptoms and improving prognosis.

Metabolic co-morbidities and psoriasis: The chicken or the egg?

Accumulating evidence supports that psoriasis may be a potential multisystem inflammatory disease associated with a range of co-morbidities showing an overlapping pathology and an important health impact such as metabolic diseases. Psoriasis is associated with an increased risk of obesity, metabolic syndrome (Mets) and diabetes mellitus type 2, following a “dose-response” relationship from mild to severe psoriasis. Conversely, recent evidence from large prospective studies suggests that obesity constitutes a risk factor for psoriasis and psoriatic arthritis. Also, a dyslipidemic profile may precede psoriasis onset. Both obesity, Mets and psoriasis, characterized as chronic inflammatory states, stem from a shared underlying pathophysiology exhibiting common genetic predisposition and risk factors such as high caloric intake, physical inactivity and psychological stress. Excess weight may potentiate the inflammation of psoriasis through the deregulation of adipocytokines while, at the same time, it may help the development of Mets. Interestingly, recent translational data has shown that psoriasis, through increased T-helper inflammatory cytokines in skin and sera, may exert a plethora of effects on insulin regulation and lipid metabolism. Larger population-based prospective cohort and longitudinal studies are needed to unravel the association between psoriasis and metabolic co-morbidities. The recognition of the intricate complex interplay between psoriasis and metabolic co-morbidities may help dermatologists to be aware of associated metabolic co-morbidities in order to screen for metabolic diseases and manage holistically and effectively the psoriatic patient.