Vascular endothelial growth factor‐A (VEGF‐A), the main angiogenic mediator, plays a critical role in the pathogenesis of several inflammatory immune‐mediated diseases, including psoriasis. Even though anti‐angiogenic therapies, such as VEGF inhibitors, are licensed for the treatment of various cancers and eye disease, VEGF‐targeting interventions are not part of current psoriasis therapy. In this viewpoint essay, we argue that the existing preclinical research evidence on the role of VEGF‐A in the pathogenesis of psoriasis as well as clinical observations in patients who have experienced psoriasis remission during oncological anti‐VEGF‐A therapy strongly suggests to systematically explore angiogenesis targeting also in the management of psoriasis. We also point out that some psoriasis therapies decrease circulating levels of VEGF‐A and normalise the psoriasis‐associated vascular pathology in the papillary dermis of plaques of psoriasis and that a subset of patients with constitutionally high levels of VEGF‐A may benefit most from the anti‐angiogenic therapy we advocate here. Given that novel, well‐targeted personalised medicine therapies for the development of psoriasis need to be developed, we explore the hypothesis that VEGF‐A and signalling through its receptors constitute a promising target for therapeutic intervention in the future management of psoriasis.

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The AHR is an environmental sensor and transcription factor activated by a variety of man-made and natural ligands, which has recently emerged as a critical regulator of homeostasis at barrier organs such as the skin. Activation of the AHR pathway downmodulates skin inflammatory responses in animal models and psoriasis clinical samples. In this study, we identify CYP1A1 enzymatic activity as a critical regulator of beneficial AHR signaling in the context of skin inflammation. Mice constitutively expressing Cyp1a1 displayed increased CYP1A1 enzymatic activity in the skin, which resulted in exacerbated immune cell activation and skin pathology, mirroring that observed in Ahr-deficient mice. Inhibition of CYP1A1 enzymatic activity ameliorated the skin immunopathology by restoring beneficial AHR signaling. Importantly, patients with psoriasis displayed reduced activation of the AHR pathway and increased CYP1A1 enzymatic activity compared with healthy donors, suggesting that dysregulation of the AHR/CYP1A1 axis may play a role in inflammatory skin disease. Thus, modulation of CYP1A1 activity may represent a promising alternative strategy to harness the anti-inflammatory effect exerted by activation of the AHR pathway in the skin.

Background/Aims: Vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, plays a key role in physiological processes and is a major contributor to several diseases including cancer and psoriasis. Anti-VEGF therapies are widely used as cancer and ophthalmological treatments. There is some evidence that VEGF blockade may have utility in the management of psoriasis, although their potential has been largely unexplored. We hypothesized that a human skin organ culture could provide a stable ex vivo model in which the cutaneous microvascular network could be studied and experimentally manipulated. Methods: Punch biopsies (3 mm) of skin, donated by healthy individuals (39–72 years old, n = 5), were incubated with monoclonal antibody (mAb) to human VEGF (bevacizumab) at doses based on data from animal and clinical studies. After 3-day culture, cell death and proliferation as well as vascular endothelial cell changes were assessed using quantitative immunohistomorphometry. Results: Anti-VEGF mAb at 0.8 mg/mL induced a significant increase in cleaved caspase-3 expression in CD31⁺ cells (p < 0.05). None of the doses tested increased TUNEL or decreased Ki-67 expression in the basal layer of the epidermis, confirming the model’s viability. In addition, the lactate dehydrogenase (LDH) assay showed no increase in LDH activity in treated samples compared to untreated control. The highest anti-VEGF mAb dose (0.8 mg/mL) induced an increase in TUNEL expression in the upper epidermis, which did not correlate with caspase-3 immunoreactivity. Further investigation revealed that anti-VEGF mAb did not change the expression of markers of terminal differentiation such as keratin 10, filaggrin, and involucrin, suggesting that VEGF depletion does not affect keratinocyte terminal differentiation. In contrast to the control group, levels of VEGF protein were undetectable in the culture supernatant of samples treated with 0.8 mg/mL of anti-VEGF mAb, suggesting sufficient dose. Conclusion: Our pilot study provides the first evidence that anti-VEGF therapy promotes endothelial cell apoptosis in human skin ex vivo. Our pragmatic human skin organ culture assay offers a valuable tool for future preclinical endothelial cell and translational microvascular network/anti-angiogenesis research in human skin.