Non-dipping nocturnal blood pressure in psoriasis vulgaris

Liangxue Jiedu formula improves imiquimod-induced psoriasiform dermatitis with circadian desynchrony by regulating Th17 cell differentiation based on network pharmacological analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Liangxue Jiedu formula (LXJDF) is an effective traditional Chinese medicine (TCM) formula for treating psoriasis of blood-heat syndrome and has been used in clinics for decades.

AIM OF THE STUDY

This study aimed to discover the mechanism of LXJDF in psoriasis and the circadian clock by network pharmacology and experimental studies.

MATERIALS AND METHODS

The compounds of LXJDF were obtained from the TCMSP and BATMAN-TCM databases. The genes related to psoriasis and circadian rhythm/clock were identified by the OMIM and GeneCards databases. Then, target genes were integrated by Venn and analyzed by the String, CytoNCA, DAVID (GO and KEGG) databases, and the network was constructed using Cytoscape. Mice were raised under light disturbance for fourteen days. On the eighth day, mouse dorsal skin was shaved and smeared with 62.5 mg 5% imiquimod at 8:00 (ZT0) for six successive days. Mice were randomly divided into the model, LXJDF-H (49.2 g/kg·bw), LXJDF-L (24.6 g/kg·bw), and positive drug (dexamethasone) groups. Other mice were smeared with Vaseline under the normal light cycle as the control. The drug of each group was administered at 10:00 (ZT2) and 22:00 (ZT14). The skin lesions were observed, and PASI was scored daily. HE and immunofluorescence were used to measure pathological morphology. Th17 cytokines in serum and skin were measured by flow cytometry and qPCR. Circadian clock gene and protein expression levels were determined by qPCR and Western blotting.

RESULTS

We found 34 potential targets of LXJDF in the treatment of psoriasis and circadian rhythm and confirmed their importance by topology analysis. KEGG pathway analysis revealed that the two major pathways were Th17 cell differentiation and the HIF-1 signaling pathway. At ZT2 and ZT14, LXJDF improved IMQ-induced light disturbance mouse skin lesions, including alleviating scales, erythema, and infiltration, reducing PASI, and inhibiting keratinocyte hyperproliferation and parakeratosis. LXJDF reduced IL-17A, IL-17F, TNF-α, and IL-6 in serum at ZT2 and increased IL-10 at ZT2 and ZT14. LXJDF downregulated the expression of IL-17A and IL-17F in skin. At ZT2, LXJDF significantly upregulated CLOCK and REV-ERBα expression and downregulated HIF-1α expression. At ZT14, LXJDF decreased HIF-1α and RORγt expression and significantly increased REV-ERBα expression.

CONCLUSION

LXJDF improves psoriasis dermatitis with circadian rhythm disorders by regulating Th17 cell differentiation.

Circadian rhythms in psoriasis and the potential of chronotherapy in psoriasis management

The physiology and pathology of the skin are influenced by daily oscillations driven by a master clock located in the brain, and peripheral clocks in individual cells. The pathogenesis of psoriasis is circadian-rhythmic, with flares of disease and symptoms such as itch typically being worse in the evening/night-time. Patients with psoriasis have changes in circadian oscillations of blood pressure and heart rate, supporting wider circadian disruption. In addition, shift work, a circadian misalignment challenge, is associated with psoriasis. These features may be due to underlying circadian control of key effector elements known to be relevant in psoriasis such as cell cycle, proliferation, apoptosis and inflammation. Indeed, peripheral clock pathology may lead to hyperproliferation of keratinocytes in the basal layers, insufficient apoptosis of differentiating keratinocytes in psoriatic epidermis, dysregulation of skin-resident and migratory immune cells and modulation of angiogenesis through circadian oscillation of vascular endothelial growth factor A (VEGF-A) in epidermal keratinocytes. Chronotherapeutic effects of topical steroids and topical vitamin D analogues have been reported, suggesting that knowledge of circadian phase may improve the efficacy, and therapeutic index of treatments for psoriasis. In this viewpoint essay, we review the current literature on circadian disruption in psoriasis. We explore the hypothesis that psoriasis is circadian-driven. We also suggest that investigation of the circadian components specific to psoriasis and that the in vitro investigation of circadian regulation of psoriasis will contribute to the development of a novel chronotherapeutic treatment strategy for personalised psoriasis management. We also propose that circadian oscillations of VEGF-A offer an opportunity to enhance the efficacy and tolerability of a novel anti-VEGF-A therapeutic approach, through the timed delivery of anti-VEGF-A drugs.

Potential effects of shift work on skin autoimmune diseases

Shift work is associated with systemic chronic inflammation, impaired host and tumor defense and dysregulated immune responses to harmless antigens such as allergens or auto-antigens. Thus, shift workers are at higher risk to develop a systemic autoimmune disease and circadian disruption with sleep impairment seem to be the key underlying mechanisms. Presumably, disturbances of the sleep-wake cycle also drive skin-specific autoimmune diseases, but epidemiological and experimental evidence so far is scarce. This review summarizes the effects of shift work, circadian misalignment, poor sleep, and the effect of potential hormonal mediators such as stress mediators or melatonin on skin barrier functions and on innate and adaptive skin immunity. Human studies as well as animal models were considered. We will also address advantages and potential pitfalls in animal models of shift work, and possible confounders that could drive skin autoimmune diseases in shift workers such as adverse lifestyle habits and psychosocial influences. Finally, we will outline feasible countermeasures that may reduce the risk of systemic and skin autoimmunity in shift workers, as well as treatment options and highlight outstanding questions that should be addressed in future studies.

Circadian Clock and OxInflammation: Functional Crosstalk in Cutaneous Homeostasis

Circadian rhythms are biological oscillations that occur with an approximately 24 h period and optimize cellular homeostasis and responses to environmental stimuli. A growing collection of data suggests that chronic circadian disruption caused by novel lifestyle risk factors such as shift work, travel across time zones, or irregular sleep-wake cycles has long-term consequences for human health. Among the multiplicity of physiological systems hypothesized to have a role in the onset of pathologies in case of circadian disruption, there are redox-sensitive defensive pathways and inflammatory machinery. Due to its location and barrier physiological role, the skin is a prototypical tissue to study the influence of environmental insults induced OxInflammation disturbance and circadian system alteration. To better investigate the link among outdoor stressors, OxInflammation, and circadian system, we tested the differential responses of keratinocytes clock synchronized or desynchronized, in an in vitro inflammatory model exposed to O₃. Being both NRF2 and NF-κB two key redox-sensitive transcription factors involved in cellular redox homeostasis and inflammation, we analyzed their activation and expression in challenged keratinocytes by O₃. Our results suggest that a synchronized circadian clock not only facilitates the protective role of NRF2 in terms of a faster and more efficient defensive response against environmental insults but also moderates the cellular damage resulting from a condition of chronic inflammation. Our results bring new insights on the role of circadian clock in regulating the redox-inflammatory crosstalk influenced by O₃ and possibly can be extrapolated to other pollutants able to affect the oxinflammatory cellular processes.

Higher Frequency of Nocturnal Blood Pressure Dipping but Not Heart Rate Dipping in Inflammatory Bowel Disease

BACKGROUND

Masked hypertension (MHTN) and lack of nocturnal dipping in blood pressure (BP) have been linked to the state of inflammation.

AIMS

We aimed to assess the frequency of nocturnal patterns of BP and heart rate (HR) in patients with IBD.

METHODS

Sixty-three normotensive patients with confirmed IBD during remission and 63 healthy subjects were enrolled in a case-control study. All subjects were monitored for BP and HR over a period of 24 h under ambulatory setting. Means for BP and HR were calculated for nighttime and daytime periods. Daytime BP ≥ 135/85 mmHg, nighttime BP ≥ 120/70 mmHg, and 24-h average BP ≥ 130/80 mmHg were defined as MHTN. The main end points of this study were lack of >10% nocturnal decrease in the systolic BP (NDP-BP) and in HR (NDP-HR).

RESULTS

After exclusion of 8 patients with IBD from analysis, 55 patients and 63 control subjects (49% men) with a mean age of 37.5 ± 11.0 years were enrolled. NDP-BP was more common in the IBD group compared to controls (55 vs. 33%; P = 0.026). MHTN was detected in 24% of IBD patients compared to 8% among controls (P = 0.017). Meanwhile, NDP-HR was observed in 22% of the IBD patients and 30% of the control group (P = 0.402). IBD remained a significant predictor of NDP-BP (odds ratio 2.60, 95% confidence interval 1.19-5.51) following an adjustment for age and gender.

CONCLUSIONS

IBD is associated with higher frequency of NDP-BP and MHTN; however, nocturnal changes in HR were similar in both groups.

Psoriasis and Cardiovascular Disease

Psoriasis is a systemic inflammatory disease that confers significant risk of metabolic derangements and adverse cardiovascular outcomes. Early detection and treatment of modifiable risk factors and modulation of the systemic inflammatory response are important treatment goals. Studies have shown that there is a significant lack of awareness of the relationship between psoriasis and cardiovascular disease, so future considerations should focus on education of and collaboration with health care providers, especially those in primary care, and development of updated, rigorous screening guidelines. In addition, targeted biologic therapies such as TNF-a inhibitors have shown immense promise in targeting the systemic inflammation associated with psoriatic disease, but whether they will impact long-term cardiovascular outcomes remains to be seen.

Circadian Gene Clock Regulates Psoriasis-Like Skin Inflammation in Mice

There are several reports suggesting that the pathophysiology of psoriasis may be associated with aberrant circadian rhythms. However, the mechanistic link between psoriasis and the circadian time-keeping system, “the circadian clock,” remains unclear. This study determined whether the core circadian gene, Clock, had a regulatory role in the development of psoriasis. For this purpose, we compared the development of psoriasis-like skin inflammation induced by the Toll-like receptor 7 ligand imiquimod (IMQ) between wild-type mice and mice with a loss-of-function mutation of Clock. We also compared the development of IMQ-induced dermatitis between wild-type mice and mice with a loss-of-function mutation of Period2 (Per2), another key circadian gene that inhibits CLOCK activity. We found that Clock mutation ameliorated IMQ-induced dermatitis, whereas the Per2 mutation exaggerated IMQ-induced dermatitis, when compared with wild-type mice associated with decreased or increased IL-23 receptor (IL-23R) expression in γ/δ⁺ T cells, respectively. In addition, CLOCK directly bound to the promoter of IL-23R in γ/δ⁺ T cells, and IL-23R expression in the mouse skin was under circadian control. These findings suggest that Clock is a novel regulator of psoriasis-like skin inflammation in mice via direct modulation of IL-23R expression in γ/δ⁺ T cells, establishing a mechanistic link between psoriasis and the circadian clock.

Ambulatory blood pressure monitoring can unmask hypertension in patients with psoriasis vulgaris

BACKGROUND

Psoriasis vulgaris is one of the most prevalent chronic, inflammatory skin disorders. Patients with psoriasis have excess risk of essential hypertension. Masked hypertension (MH), defined as normal office blood pressure (BP) with elevated ambulatory BP (ABPM), has been drawing attention recently due to its association with increased risk of developing sustained hypertension, cardiovascular morbidity, and mortality. The aim of this study was to investigate the prevalence of MH in psoriatic patients.

MATERIAL AND METHODS

On hundred and ten middle-aged, normotensive, non-obese patients with psoriasis vulgaris and 110 age- and sex-matched normotensive controls were included in the study. ABPM was performed in all participants over a 24-h period. The clinical severity of the disease was determined according to current indexes.

RESULTS

The prevalence of MH among subjects with psoriasis vulgaris was 31.8% and increased compared to control subjects (p<0.01). Predictors of MH in patients with psoriasis vulgaris were detected as male sex, smoking, obesity-related anthropometric measures, and disease activity. Male sex, waist circumference, and diffuse psoriatic involvement were detected as independent predictors of MH.

CONCLUSIONS

MH is prevalent in patients with psoriasis vulgaris. Assessment with ABPM and close follow-up for development of hypertension is reasonable.

Aortic arterial stiffness is a moderate predictor of cardiovascular disease in patients with psoriasis vulgaris

Psoriasis is associated with an increased risk of atherosclerosis. Endothelial dysfunction is the critical early step in the process of atherogenesis, and it is commonly investigated by measuring arterial stiffness. We aimed to investigate the relationship between arterial stiffness and high-sensitivity C-reactive protein (hsCRP) in patients with psoriasis. A total of 32 patients with psoriasis and 35 patients with other skin diseases were included in the study. The hsCRP levels and arterial stiffness measurements were compared. Arterial stiffness was significantly different between the 2 groups (P = .01). Arterial stiffness was not associated with the duration of the disease or the disease activity (P = .34 and .64, respectively). In patients with psoriasis, arterial stiffness correlated positively with age, sex, body mass index, diastolic blood pressure, and hsCRP level (P < .05). These findings provide further evidence of a link between inflammation, premature atherosclerosis, and psoriasis.