Cumulative methotrexate dose is not associated with liver fibrosis in patients with a history of moderate to severe psoriasis.

BACKGROUND: Liver fibrosis (LF) has established risk factors, but data on the impact of methotrexate on LF in psoriasis patients are lacking. This cross-sectional study aimed to determine the prevalence of LF in psoriasis patients and to evaluate the relationship between LF, cumulative methotrexate dose and other LF risk factors. METHODS: Adults with a history of moderate to severe chronic plaque psoriasis were recruited between June 2020 and March 2021. Patients underwent transient elastography to evaluate LF. Three values for liver stiffness measurement (LSM) were assessed, indicating mild or worse LF (≥7kPa), moderate or worse LF (≥7.9 kPa) and advanced LF (≥9.5kPa). Cumulative methotrexate dose and other potential risk factors for LF were assessed. RESULTS: 240 patients were recruited and 204 participants with valid LSM values were included in the analysis (median age 48 (IQR 37,57) years; 51% female; 56% Body Mass Index (BMI) ≥30 kg/m2 and median Alcohol Use Disorders Identification Test (AUDIT) score 4 (IQR 1,7, 23% score ≥ 8)). 91% had received methotrexate (median duration 36 months (IQR 14,78)). Prevalence of LF was 36%, 25% and 17 % using LSM ≥7kPa, ≥7.9 kPa and ≥9.5kPa respectively. There was no association between cumulative methotrexate dose (median 2.16 (IQR 0.93, 5.2) and continuous LSM values (unstandardised coefficient 0.16, (95% CI -0.49-0.82, p=0.626) or using the categorical LSM cut off values: ≥7kPa (unadjusted odds ratio 1.06 (95% CI 0.97-1.15), p= 0.192), ≥7.9 kPa (unadjusted odds ratio 1.03 (95% CI 0.94- 1.12), p= 0.577) and ≥9.5kPa (unadjusted odds ratio 1.01 (95% CI 0.91-1.12) p=0.843).The following risk factors were associated with higher LSM values: BMI (p=<0.001), Waist circumference (p=<0.001), metabolic syndrome (p=<0.001), AUDIT score (P=0.020), FIB-4 score (p= 0.03). BMI ≥28, diabetes and metabolic syndrome were shown to be better predictors of LF compared to Fib 4 score. CONCLUSION: This study confirms a high prevalence of significant LF in patients with psoriasis. Cumulative methotrexate dose was not associated with LF. Patients with BMI ≥28 kg/m2, metabolic syndrome and diabetes are at higher risk for LF. These risk factor may help to identify when a more detailed liver health assessment is needed.

Individualised computational modelling of immune mediated disease onset, flare and clearance in psoriasis.

Despite increased understanding about psoriasis pathophysiology, currently there is a lack of predictive computational models. We developed a personalisable ordinary differential equations model of human epidermis and psoriasis that incorporates immune cells and cytokine stimuli to regulate the transition between two stable steady states of clinically healthy (non-lesional) and disease (lesional psoriasis, plaque) skin. In line with experimental data, an immune stimulus initiated transition from healthy skin to psoriasis and apoptosis of immune and epidermal cells induced by UVB phototherapy returned the epidermis back to the healthy state. Notably, our model was able to distinguish disease flares. The flexibility of our model permitted the development of a patient-specific "UVB sensitivity" parameter that reflected subject-specific sensitivity to apoptosis and enabled simulation of individual patients' clinical response trajectory. In a prospective clinical study of 94 patients, serial individual UVB doses and clinical response (Psoriasis Area Severity Index) values collected over the first three weeks of UVB therapy informed estimation of the "UVB sensitivity" parameter and the prediction of individual patient outcome at the end of phototherapy. An important advance of our model is its potential for direct clinical application through early assessment of response to UVB therapy, and for individualised optimisation of phototherapy regimes to improve clinical outcome. Additionally by incorporating the complex interaction of immune cells and epidermal keratinocytes, our model provides a basis to study and predict outcomes to biologic therapies in psoriasis.

Spectral effects of UV on psoriasis.

Ultraviolet B (UVB) is a highly effective, relatively safe, affordable and widely used therapeutic option for moderate psoriasis. Several types of UVB lamp are available to treat psoriasis, both broadband and narrowband, allowing a choice of spectral emission. However despite years of clinical use, the mechanism of action of UVB in clearing psoriasis remained incompletely understood. Moreover, there has been little insight into how the relative effectiveness of different UVB wavelengths linked to the mechanism of action, although it is known that the action spectrum for clearance of psoriasis differs from the action spectrum of erythema. This paper examines the existing literature from which our current treatments have evolved, and offers new insight into the use of keratinocyte apoptosis as a biomarker which may help to optimise UV treatment in the future. When combined with a systems biology approach, this potential biomarker may provide insight into which wavelengths of UV are the most effective in clearing psoriasis, allowing a more rational and potentially an individually tailored approach to optimising phototherapy for psoriasis.

Therapeutic wavelengths of ultraviolet B radiation activate apoptotic, circadian rhythm, redox signalling and key canonical pathways in psoriatic epidermis.

Ultraviolet B radiation (UVB) exerts pleiotropic effects on human skin. DNA damage response and repair pathways are activated by UVB; if damage cannot be repaired, apoptosis ensues. Although cumulative UVB exposure predisposes to skin cancer, UVB phototherapy is widely used as an effective treatment for psoriasis. Previous studies defined the therapeutic action spectrum of UVB and showed that psoriasis is resistant to apoptosis. This study aimed to investigate early molecular responses within psoriasis plaques following irradiation with single equi-erythemogenic doses of clinically-effective (311 nm, narrow-band) compared to clinically-ineffective (290 nm) UVB. Forty-eight micro-dissected epidermal samples from 20 psoriatic patients were analyzed using microarrays. Our bioinformatic analysis compared gene expression between 311 nm irradiated, 290 nm irradiated and control psoriasis epidermis to specifically identify 311 nm UVB differentially expressed genes (DEGs) and their upstream regulatory pathways. Key DEGs and pathways were validated by immunohistochemical analysis. There was a dynamic induction and repression of 311 nm UVB DEGs between 6 h and 18 h, only a limited number of DEGs maintained their designated expression status between time-points. Key disease and function pathways included apoptosis, cell death, cell migration and leucocyte chemotaxis. DNA damage response pathways, NRF2-mediated oxidative stress response and P53 signalling were key nodes, interconnecting apoptosis and cell cycle arrest. Interferon signalling, dendritic cell maturation, granulocyte adhesion and atherosclerotic pathways were also differentially regulated. Consistent with these findings, top transcriptional regulators of 311 nm UVB DEGs related to: a) apoptosis, DNA damage response and cell cycle control; b) innate/acquired immune regulation and inflammation; c) hypoxia/redox response and angiogenesis; d) circadian rhythmicity; f) EGR/AP1 signalling and keratinocyte differentiation; and g) mitochondrial biogenesis. This research provides important insights into the molecular targets of 311 nm UVB, underscoring key roles for apoptosis and cell death. These and the other key pathways delineated may be central to the therapeutic effects of 311 nm in psoriasis.

The Results of Low-Dose Total Skin Electron Beam Radiation Therapy (TSEB) in Patients With Mycosis Fungoides From the UK Cutaneous Lymphoma Group.

PURPOSE: Total skin electron beam radiation therapy (TSEB) is a very effective treatment of mycosis fungoides. Following reports of similar durations of response to lower doses of TSEB, a low-dose schedule of TSEB was introduced in the United Kingdom. METHODS AND MATERIALS: A protocol of 12 Gy in 8 fractions over a period of 2 weeks was agreed on by use of the Stanford University technique. Data were collected prospectively, and the results were analyzed according to the European Organisation for Research and Treatment of Cancer-International Society for Cutaneous Lymphomas endpoints (EORTC-ISCL). Toxicity was scored according to CTCAE v4.0 (Common Terminology Criteria for Adverse Events version 4.0). RESULTS: One hundred three patients received treatment, with a median follow-up period of 20.6 months (range, 3.3-53 months). Of these patients, 54 had stage IB disease, 33 had stage IIB, 12 had stage III, and 4 had stage IV. The median age was 68 years (range, 26-91 years). The complete response rate was 18%, the partial response rate was 69%, stable disease was present in 8%, and progression on treatment was found in 5%. In the patients who had a complete response, the median time to relapse was 7.3 months. The median response duration was 11.8 months. Median progression-free survival for all patients was 13.2 months. It was significantly longer, at 26.5 months, in patients with stage IB disease compared with 11.3 months in patients with stage IIB (P=.003; hazard ratio, 2.66) and 10.2 months in patients with stage III (P=.002; hazard ratio, 4.62). The treatment was well tolerated with lower toxicity than higher-dose schedules. CONCLUSIONS: The low-dose TSEB schedule of 12 Gy in 8 fractions over a period of 2 weeks is well tolerated and is an effective option for patients with mycosis fungoides.

Keratinocyte apoptosis in epidermal remodeling and clearance of psoriasis induced by UV radiation.

Psoriasis is a common chronic skin disorder, but the mechanisms involved in the resolution and clearance of plaques remain poorly defined. We investigated the mechanism of action of UVB, which is highly effective in clearing psoriasis and inducing remission, and tested the hypothesis that apoptosis is a key mechanism. To distinguish bystander effects, equal erythemal doses of two UVB wavelengths were compared following in vivo irradiation of psoriatic plaques; one is clinically effective (311 nm) and one has no therapeutic effect on psoriasis (290 nm). Only 311 nm UVB induced significant apoptosis in lesional epidermis, and most apoptotic cells were keratinocytes. To determine clinical relevance, we created a computational model of psoriatic epidermis. Modeling predicted apoptosis would occur in both stem and transit-amplifying cells to account for plaque clearance; this was confirmed and quantified experimentally. The median rate of keratinocyte apoptosis from onset to cell death was 20 minutes. These data were fed back into the model and demonstrated that the observed level of keratinocyte apoptosis was sufficient to explain UVB-induced plaque resolution. Our human studies combined with a systems biology approach demonstrate that keratinocyte apoptosis is a key mechanism in psoriatic plaques clearance, providing the basis for future molecular investigation and therapeutic development.