IL-17A and TNF-α inhibitors induce multiple molecular changes in psoriasis

Sensory neurons increase keratinocyte proliferation through CGRP release in a tissue engineered in vitro model of innervation in psoriasis

Skin denervation has been shown to cause remission of psoriatic lesions in patients, which can reappear if reinnervation occurs. This effect can be induced by the activation of dendritic cells through sensory innervation. However, a direct effect of nerves on the proliferation of keratinocytes involved in the formation of psoriatic plaques has not been investigated. We developed, by tissue engineering, a model of psoriatic skin made of patient skin cells that showed increased keratinocyte proliferation and epidermal thickness compared to healthy controls. When this model was treated with CGRP, a neuropeptide released by sensory neurons, an increased keratinocyte proliferation was observed in the psoriatic skin model, but not in the control. When a sensory nerve network was incorporated in the psoriatic model and treated with capsaicin to induce neuropeptide release, an increase of keratinocyte proliferation was confirmed, which was blocked by a CGRP antagonist while no difference was noticed in the innervated healthy control. We showed that sensory neurons can participate directly to keratinocyte hyperproliferation in the formation of psoriatic lesions through the release of CGRP, independently of the immune system. Our unique tissue-engineered innervated psoriatic skin model could be a valuable tool to better understand the mechanism by which nerves may modulate psoriatic lesion formation in humans. STATEMENT OF SIGNIFICANCE: This study shows that keratinocytes extracted from patients' psoriatic skin retain, at least in part, the disease phenotype. Indeed, when combined in a 3D model of tissue-engineered psoriatic skin, keratinocytes exhibited a higher proliferation rate, and produced a thicker epidermis than a healthy skin control. In addition, their hyperproliferation was aggravated by a treatment with CGRP, a neuropeptide released by sensory nerves. In a innervated model of tissue-engineered psoriatic skin, an increase in keratinocyte hyperproliferation was also observed after inducing neurons to release neuropeptides. This effect was prevented by concomitant treatment with an antagonist to CGRP. Thus, this study shows that sensory nerves can directly participate to affect keratinocyte hyperproliferation in psoriasis through CGRP release.

Impact of Blood-Count-Derived Inflammatory Markers in Psoriatic Disease Progression

Psoriasis is a chronic immune-mediated disease, linked to local and systemic inflammation and predisposing patients to a higher risk of associated comorbidities. Cytokine levels are not widely available for disease progression monitoring due to high costs. Validated low-cost and reliable markers are needed for assessing disease progression and outcome. This study aims to assess the reliability of blood-count-derived inflammatory markers as disease predictors and to identify prognostic factors for disease severity. Patients fulfilling the inclusion criteria were enrolled in this study. Patients were divided into three study groups according to disease severity measured by the Body Surface Area (BSA) score: mild, moderate, and severe psoriasis. White blood cell count (WBC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), derived neutrophil-to-lymphocyte ratio (d-NLR), systemic immune index (SII), systemic inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI) positively were correlated with disease severity (p < 0.005). d-NLR, NLR, and SII are independent prognostic factors for mild and moderate psoriasis (p < 0.05). d-NLR is the only independent prognostic factor for all three study groups. Moderate psoriasis is defined by d-NLR values between 1.49 and 2.19. NLR, PLR, d-NLR, MLR, SII, SIRI, and AISI are useful indicators of systemic inflammation and disease severity in psoriasis.

Impact of Pretreatment Systemic Inflammatory Markers on Treatment Persistence with Biologics and Conventional Systemic Therapy: A Retrospective Study of Patients with Psoriasis Vulgaris and Psoriatic Arthritis

Systemic inflammation plays a central role in the pathophysiology of psoriasis. This study examined accessible systemic inflammatory markers in patients with psoriasis vulgaris and psoriatic arthritis. We aimed to evaluate their association with psoriasis severity, the presence of arthritis, and drug continuation rates. The findings revealed that neutrophil, monocyte, and platelet count, neutrophil/lymphocyte ratio, monocyte/lymphocyte ratio, systemic inflammation response index, systemic immune/inflammation index (SII), and CRP were positively correlated with Psoriasis Area and Severity Index scores. Patients presenting with higher platelet/lymphocyte ratio (PLR) or CRP values were more likely to be diagnosed with psoriatic arthritis than with psoriasis vulgaris in the multivariate regression analysis. Importantly, patients with higher pretreatment neutrophil or platelet count, PLR, and SII were associated with lower treatment continuation rates of conventional systemic agents. Higher pretreatment scores of systemic inflammatory markers did not affect treatment retention rates of biologics. These findings suggest that several accessible systemic inflammatory markers may effectively assess underlying systemic inflammation and may provide an indication for a therapeutic approach in patients with psoriasis vulgaris and psoriatic arthritis.