Whole field laser Doppler imaging of the microcirculation in psoriasis and clinically unaffected skin

Factor XII and prekallikrein promote microvascular inflammation and psoriasis in mice

BACKGROUND AND PURPOSE

Psoriasis is an autoimmune inflammatory skin disease, featuring microvascular abnormalities and elevated levels of bradykinin. Contact activation of Factor XII can initiate the plasma kallikrein-kinin cascade, producing inflammation and angioedema. The role of Factor XII in psoriasis is unknown.

EXPERIMENTAL APPROACH

The effects of deficiency of Factor XII or its enzymatic substrate, prekallikrein, were examined in the imiquimod-induced mouse model of psoriasis. Skin microcirculation was assessed using intravital confocal microscopy and laser Doppler flowmeter. A novel antibody blocking Factor XII activation was evaluated for psoriasis prevention.

KEY RESULTS

Expression of Factor XII was markedly up-regulated in human and mouse psoriatic skin. Genetic deletion of Factor XII or prekallikrein, attenuated imiquimod-induced psoriatic lesions in mice. Psoriatic induction increased skin microvascular blood perfusion, causing vasodilation, hyperpermeability and angiogenesis. It also promoted neutrophil-vascular interaction, inflammatory cytokine release and enhanced Factor XII / prekallikrein enzymatic activity with elevated bradykinin. Factor XII or prekallikrein deficiency ameliorated these microvascular abnormalities and abolished bradykinin increase. Antagonism of bradykinin B2 receptors reproduced the microvascular protection of Factor XII / prekallikrein deficiency, attenuated psoriatic lesions, and prevented protection by Factor XII / prekallikrein deficiency against psoriasis. Furthermore, treatment of mice with Factor XII antibody alleviated experimentally induced psoriasis and suppressed microvascular inflammation.

CONCLUSION AND IMPLICATIONS

Activation of Factor XII promoted psoriasis via prekallikrein-dependent formation of bradykinin, which critically mediated psoriatic microvascular inflammation. Inhibition of contact activation represents a novel therapeutic strategy for psoriasis.

Detection of microvascular changes in systemic sclerosis and other rheumatic diseases

Morphological and functional analysis of the microcirculation are objective outcome measures that are recommended for use in the presence of clinical signs of altered peripheral blood flow (such as Raynaud phenomenon), which can occur in systemic sclerosis (SSc) and other autoimmune rheumatic diseases. Several advanced non-invasive tools are available for monitoring the microcirculation, including nailfold videocapillaroscopy, which is the best-studied and most commonly used method for distinguishing and quantifying microvascular morphological alterations in SSc. Nailfold videocapillaroscopy can also be used alongside laser Doppler techniques to assist in the early diagnosis and follow-up of patients with dermatomyositis or mixed connective tissue disease. Power Doppler ultrasonography, which has been used for many years to evaluate the vascularity of synovial tissue in rheumatoid arthritis, is another promising tool for the analysis of skin and nailbed capillary perfusion in other autoimmune rheumatic diseases. Other emerging methods include raster-scanning optoacoustic mesoscopy, which offers non-invasive high-resolution 3D visualization of capillaries and has been tested in psoriatic arthritis and SSc. The principle functions and operative characteristics of several non-invasive tools for analysing microvascular changes are outlined in this Review, and the clinical roles of validated or tested imaging methods are discussed for autoimmune rheumatic diseases.

Perfusion measured by laser speckle contrast imaging as a predictor for expansion of psoriasis lesions

Background

Skin microvasculature changes are crucial in psoriasis development and correlate with perfusion. The noninvasive Handheld Perfusion Imager (HAPI) examines microvascular skin perfusion in large body areas using laser speckle contrast imaging (LSCI).

Objectives

To (i) assess whether increased perilesional perfusion and perfusion inhomogeneity are predictors for expansion of psoriasis lesions and (ii) assess feasibility of the HAPI system in a mounted modality.

Methods

In this interventional pilot study in adults with unstable plaque psoriasis, HAPI measurements and color photographs were performed for lesions present on one body region at week 0, 2, 4, 6 and 8. The presence of increased perilesional perfusion and perfusion inhomogeneity was determined. Clinical outcome was categorized as increased, stable or decreased lesion surface between visits. Patient feedback was collected on a 10‐point scale.

Results

In total, 110 lesions with a median follow‐up of 6 (IQR 6.0) weeks were assessed in 6 patients with unstable plaque psoriasis. Perfusion data was matched to 281 clinical outcomes after two weeks. A mixed multinomial logistic regression model revealed a predictive value of perilesional increased perfusion (OR 9.90; p < 0.001) and perfusion inhomogeneity (OR 2.39; p = 0.027) on lesion expansion after two weeks compared to lesion stability. HAPI measurements were considered fast, patient‐friendly and important by patients.

Conclusion

Visualization of increased perilesional perfusion and perfusion inhomogeneity by noninvasive whole field LSCI holds potential for prediction of psoriatic lesion expansion. Furthermore, the HAPI is a feasible and patient‐friendly tool.

Handheld versus mounted laser speckle contrast perfusion imaging demonstrated in psoriasis lesions

Enabling handheld perfusion imaging would drastically improve the feasibility of perfusion imaging in clinical practice. Therefore, we examine the performance of handheld laser speckle contrast imaging (LSCI) measurements compared to mounted measurements, demonstrated in psoriatic skin. A pipeline is introduced to process, analyze and compare data of 11 measurement pairs (mounted-handheld LSCI modes) operated on 5 patients and various skin locations. The on-surface speeds (i.e. speed of light beam movements on the surface) are quantified employing mean separation (MS) segmentation and enhanced correlation coefficient maximization (ECC). The average on-surface speeds are found to be 8.5 times greater in handheld mode compared to mounted mode. Frame alignment sharpens temporally averaged perfusion maps, especially in the handheld case. The results show that after proper post-processing, the handheld measurements are in agreement with the corresponding mounted measurements on a visual basis. The absolute movement-induced difference between mounted-handheld pairs after the background correction is [Formula: see text] (mean ± std, [Formula: see text]), with an absolute median difference of [Formula: see text]. Realization of handheld LSCI facilitates measurements on a wide range of skin areas bringing more convenience for both patients and medical staff.

Investigation of water bonding status of normal and psoriatic skin in vivo using diffuse reflectance spectroscopy

Psoriasis affects more than 125 million people worldwide, and the diagnosis and treatment efficacy evaluation of the disease mainly rely on clinical assessments that could be subjective. Our previous study showed that the skin erythema level could be quantified using diffuse reflectance spectroscopy (DRS), and the hemoglobin concentration of most psoriatic lesion was higher than that of its adjacent uninvolved skin. While the compromised epidermal barrier function has been taken as the major cause of clinical manifestation of skin dryness and inflammation of psoriasis, very few methods can be used to effectively evaluate this function. In this study, we investigate the near infrared spectroscopic features of psoriatic (n = 21) and normal (n = 21) skin that could link to the epidermal barrier function. From the DRS measurements, it was found that the water bonding status and light scattering properties of psoriasis are significantly different from those of uninvolved or normal skin. The connection between these parameters to the epidermal barrier function and morphology will be discussed. Our results suggest that objective evaluation of epidermal barrier function of psoriasis could be achieved using a simple DRS system.

Pathogenesis of psoriasis in the "omic" era. Part III. Metabolic disorders, metabolomics, nutrigenomics in psoriasis

Psoriasis is a systemic disease that is strictly connected with metabolic disorders (insulin resistance, atherogenic dyslipidemia, arterial hypertension, and cardiovascular diseases). It occurs more often in patients with a more severe course of the disease. Obesity is specially an independent risk factor and it is associated with a worse treatment outcome because of the high inflammatory activity of visceral fatty tissue and the production of inflammatory mediators involved in the development of both psoriasis and metabolic disorders. However, in psoriasis the activation of the Th17/IL-17 and the abnormalities in the Th17/Treg balance axis are observed, but this pathomechanism does not fully explain the frequent occurrence of metabolic disorders. Therefore, there is a need to look for better biomarkers in the diagnosis, prognosis and monitoring of concomitant disorders and therapeutic effects in psoriasis. In addition, the education on the use of a proper diet as a prophylaxis for the development of the above disorders is an important element of holistic care for a patient with psoriasis. Diet may affect gene expression due to epigenetic modification which encompasses interactions of environment, nutrition and diseases. Patients with psoriasis should be advised to adopt proper diet and dietician support.

Pathogenesis of psoriasis in the "omic" era. Part I. Epidemiology, clinical manifestation, immunological and neuroendocrine disturbances

Psoriasis is a common, chronic, inflammatory, immune-mediated skin disease affecting about 2% of the world's population. According to current knowledge, psoriasis is a complex disease that involves various genes and environmental factors, such as stress, injuries, infections and certain medications. The chronic inflammation of psoriasis lesions develops upon epidermal infiltration, activation, and expansion of type 1 and type 17 Th cells. Despite the enormous progress in understanding the mechanisms that cause psoriasis, the target cells and antigens that drive pathogenic T cell responses in psoriatic lesions are still unproven and the autoimmune basis of psoriasis still remains hypothetical. However, since the identification of the Th17 cell subset, the IL-23/Th17 immune axis has been considered a key driver of psoriatic inflammation, which has led to the development of biologic agents that target crucial elements of this pathway. Here we present the current understanding of various aspects in psoriasis pathogenesis.

Sterol-standardized phytopharmaceutical from ground cherry: Corticoid-like properties on human keratinocytes and fibroblasts and its effects in a randomized double-blind placebo-controlled clinical trial

BACKGROUND

Topical corticosteroids have been the most commonly prescribed drugs to treat skin inflammation, but their uses can lead to several adverse effects. Nowadays, new pharmacological strategies have been evaluated to improve dermatologic efficacy and reduce adverse effects, including natural products.

OBJECTIVES

The aim of this study was to evaluate and compare the effects of a plant sterol standardized supercritical CO₂ phytopharmaceutical of Physalis angulata L. with hydrocortisone on the immune and inflammatory mediators, and skin repair components production. Moreover, we studied effects of both products on the skin microcirculation and temperature in a double-blind placebo-controlled clinical trial.

METHODS

Both products were evaluated on the immune (IL-6, IL-10, INF-γ, TNF-α, and IL-1α), inflammatory (COX-2, LOX, PLA₂ , PGE₂ , LTB₄ , histamine, and NF-κB), and repair components (TGF-β, GM-CSF, collagen, and GAG) production on human keratinocytes and fibroblast in non-stimulated and LPS-stimulated conditions. Indeed, in a randomized double-blind placebo-controlled clinical trial, we evaluated the effects of the both creams on the skin microcirculation and temperature using laser Doppler and infrared thermometer, respectively.

RESULTS

Physalis angulata acted on the skin, modulating immune status and inflammatory response producing corticoid-like effects, but different of hydrocortisone, increased skin repair factors. The effects of phytopharmaceutical cream in the clinical trial promoted a better reduction in skin microcirculation and temperature than hydrocortisone.

CONCLUSIONS

Taken together, the results indicate that sterol standardized CO₂ supercritical preparation of P angulata is a new and innovative phytopharmaceutical with multiple pharmacological effects potentially useful as human skin protective product, particularly against cutaneous inflammatory disorders.

Validity and sensitivity to change of laser Doppler imaging as a novel objective outcome measure for cutaneous lupus erythematosus

OBJECTIVES

The objectives of this study were to assess the reliability of a novel objective outcome measure, laser Doppler imaging (LDI), its validity against skin biopsy histology and other clinical instruments, including localized cutaneous lupus disease area and severity index (L-CLASI) and visual analogue scale (VAS) score of photographs, and its responsiveness to clinical change with therapy.

METHODS

A prospective observational cohort study was conducted in 30 patients with active cutaneous lupus erythematosus (CLE). At baseline and 3 months, disease activity was assessed using L-CLASI and a high resolution LDI system by two assessors. Skin biopsy was scored as 0 = non-active, 1 = mild activity and 2 = active. Photographs were assessed by two clinicians using 100 mm VAS. Inter-rater reliability was analyzed using Bland-Altman limits of agreement. Correlation between histology and LDI, L-CLASI and VAS and sensitivity to change of LDI with physician subjective assessment of change (PSAC) at 3 months were analyzed using Kendall's tau-a.

RESULTS

Of 30 patients with CLE, 28 (93%) were female, mean (SD) age 48.4 (11.5) y, 25 (83%) were Caucasians, 25 (83%) had concurrent systemic lupus erythematosus and 16 (53%) were smokers. CLE subtypes were acute = 9, subacute = 8 and chronic = 13. Inter-rater agreement for LDI was fair but for VAS score of photographs was poor. In 20 patients with biopsy, correlation with histology was better for LDI (tau-a = 0.53) than L-CLASI (tau-a = 0.26) (difference = 0.27; 90% CI 0.05-0.49) or VAS score of photographs (tau-a = 0.17) (difference = 0.36; 90% CI 0.04-0.68). There was a moderate correlation between PSAC score and change in LDI (tau-a = 0.56; 90% CI 0.38-0.74; p < 0.001, n = 15).

CONCLUSION

LDI provides a reliable, valid and responsive quantitative measure of inflammation in CLE. It has a better correlation with histology compared to clinical instruments. LDI provides an objective outcome measure for clinical trials.

Non-invasive Approaches for the Diagnosis of Autoimmune/Autoinflammatory Skin Diseases-A Focus on Psoriasis and Lupus erythematosus

The traditional diagnostic gold standard for inflammatory skin lesions of unclear etiology is dermato-histopathology. As this approach requires an invasive skin biopsy, biopsy processing and analysis by specialized histologists, it is a resource intensive approach requiring trained healthcare professionals. In many health care settings access to this diagnostic approach can be difficult and outside emergency cases will usually take several weeks. This scenario leads to delayed or inappropriate treatment given to patients. With dramatically increased sensitivity of a range of analysis systems including mass spectrometry, high sensitivity, multiplex ELISA based systems and PCR approaches we are now able to "measure" samples with unprecedented sensitivity and accuracy. Other important developments include the long-term monitoring of parameters using microneedle approaches and the improvement in imaging systems such as optical coherence tomography. In this review we will focus on recent achievements regarding measurements from non-invasive sampling, in particular from plucked hair and skin tape-strips which seem well suited for the diagnosis of lupus erythematosus and psoriatic inflammation, respectively. While these approaches will not replace clinical observation-they can contribute to improved subgroup diagnosis, stratified therapeutic approaches and have great potential for providing molecular and mechanistic insight in to inflammatory skin diseases.

The dynamics of endothelial changes in vivo following standardized skin injury

BACKGROUND

Vascular changes, that is, functional and cellular endothelial changes, are of essential importance in healing. Alongside these vascular changes, inflammatory factors and hypoxia may play an important role in recovery.

OBJECTIVES

To investigate the dynamics of functional and cellular endothelial changes and hypoxia in vivo following standardized skin damage caused by tape stripping.

METHODS

Vascular changes (endothelial cell proliferation, vascular network size, vessel diameter) and hypoxia-inducible factor-1α were examined immunohistochemically using a CD31/Ki67 double staining and HIF-1α single staining. Cutaneous perfusion was evaluated using the Twente Optical Perfusion Camera (TOPCam).

RESULTS

The initial phase is seen to be dominated by endothelial cell proliferation, HIF-1α expression, and vasodilatation. Cutaneous perfusion intensity is particularly increased in the first 16 hours. The late phase of recovery (after 72 hours) is characterized by a peak of expansion of the vascular network and a second peak of endothelial cell proliferation and HIF-1α expression.

CONCLUSION

Endothelial cell proliferation and HIF-1α expression appear to be (strongly) related, having maximum levels at 16 hours and 72 hours. Angiogenesis and HIF-1α expression are not continuous processes, but rather occur intermittently.

Pilot Study of Laser Doppler Measurement of Flow Variability in the Microcirculation of the Palatal Mucosa

Background. Histopathological alterations can arise when the denture-supporting mucosa experiences microbial and mechanical stress through the denture base and diagnosis of these diseases usually follows microvascular changes. Microcirculation measurement could allow for detection of such dysfunction and aid in the early diagnosis of palatal mucosa pathologies. Materials and Methods. We tested the sensitivity of laser Doppler for measuring the microcirculation of the palatal mucosa, assessing the median raphe (MR), Schroeder area (SA), and retroincisive papilla (RP). A Doppler PeriFlux 5000 System, containing a laser diode, was used. 54 healthy participants were recruited. We compare the measurements of PU (perfusion unit) using ANOVA test. Results. The numerical values for palatal mucosa blood flow differed significantly among the anatomical areas (p = 0.0167). The mean value of Schroeder area was 92.6 (SD: 38.4) and was significantly higher than the retroincisive papilla (51.9) (SD: 20.2) (p < 0.05), which in turn was higher than that of median raphe (31.9) (SD: 24.2) (p < 0.0001). Conclusion. Schroeder area appeared to have the greatest sensitivity, and vascular flow variability among individuals was also greatest in this region. We suggest that analysis of blood stream modification with laser Doppler of the palatal mucosa can help to detect onset signs of pathological alterations.

Study of in vitro capillary-like structures in psoriatic skin substitutes

Angiogenesis is one of the important hallmarks of psoriasis. The extension of the superficial microvascular structure and activated pro-angiogenic mediators in psoriasis seem to be important factors involved in the pathology. According to the changes of superficial microvasculature in psoriatic lesions, anti-angiogenic treatment could be a promising therapeutic strategy for psoriasis. The aim of this study was to construct an in vitro vascularized psoriatic skin substitute for fundamental research. Psoriatic fibroblasts and keratinocytes were isolated from psoriatic plaque biopsies, while healthy fibroblasts and keratinocytes, as well as microvascular endothelial cells, were isolated from healthy skin biopsies of cosmetic breast surgery. Psoriatic and healthy skin substitutes with and without endothelial cells were produced using the self-assembly approach. Afterward the substitutes were examined by histology, immunofluorescence studies, and three-dimensional (3D) confocal microscopy. Histological analysis and immunofluorescence staining of specific markers for endothelial cells (von Willebrand, PECAM-1 [CD31], and VE-cadherin [CD144]) and basement membrane component (collagen IV) demonstrated that endothelial cells have the ability to form capillary-like tubes. Moreover, the 3D branched structure of the capillary-like structures and an eagle eye view of them were observed by confocal microscopy. Also the semiquantification of capillary-like tubes (CLTs) was carried out with a 3D eagle eye view of substitutes, and more CLTs were observed in psoriatic substitutes. These results suggest that it is possible to observe 3D capillary-like structures in the self-assembled psoriatic skin substitutes, which could become a good in vitro testing model for anti-angiogenic drug research, and facilitate the study of this complex pathology, which links angiogenesis to its development.