Erythrocyte-derived microparticles containing near-infrared (NIR) dyes such as indocyanine green present a promising cell-based platform for optical imaging and phototherapeutics. Using real-time intravital NIR fluorescence imaging of mice vasculature, we investigated the effects of blood type, specifically O+ and B+, used in fabricating these particles, the number concentration (Nv) of the particles, and the relocalization of phosphatidylserine (PS) to the outer leaflet of the particles' membrane on the resulting circulation dynamics following a single retro-orbital injection. Additionally, we quantified the biodistribution of particles in various organs. We found that the fluorescence emission half-life for particles engineered from O+ blood type extended from 11.4 ± 3.0 to 43.1 ± 9.6 min with increased Nv from a low range of 0.4-0.6 to high range of 1.4-1.6 million particles/per μL, when only 30-55% of the particles demonstrated externalized PS. For these particles, the liver and gallbladder, lungs, and spleen showed similar levels of accumulation at 60 min post administration. When >90% of O+-particles showed PS externalization, or when the particles were fabricated from B+ blood type despite PS externalization in 30-55% of the particles, the emission half-life was reduced to 15.8 ± 5.9 and 18.1 ± 4.6 min, respectively. There was lower accumulation of these particles in the spleen as compared to the liver and gallbladder and the lungs. In vitro experiments demonstrated increased PS externalization correlated to a more efficient uptake of the particles by macrophages. These findings emphasize the importance of blood type, Nv, and PS in engineering erythrocyte-derived particles for future clinical applications.

Martin C. (Marty) Mihm made multiple, pivotal contributions over four decades of discovery, innovation, and development leading to the world-wide application of lasers in dermatology. This started with trying to understand how pulses of light could be tailored to affect microscopic "target" structures in skin where the light is absorbed. There were many surprises, often first observed by light or electron microscopy. A host of new capabilities ensued, including laser treatments for microvascular and vascular malformations, non-melanoma pigmented lesions, tattoo and hair removal, rehabilitation of scars, improvement of photoaged skin, and lipid-targeting lasers for reduction of fat and acne. Dr. Mihm extended himself directly to patients, especially children with vascular anomalies. He contributed to the discovery that GLUT1, a glucose transporter expressed on vascular endothelium, is a defining diagnostic for infantile hemangiomas. He established a multispecialty vascular-anomalies clinic at the Massachusetts General Hospital, and co-founded the Vietnam Vascular Anomalies Center (VVAC) in Ho Chi Minh City. In Vietnam, topical radioactive phosphorus (32P) is applied as a misguided treatment for infantile hemangiomas, leading to radiation damage in uncounted thousands of children. By teaching the use of beta-adrenergic drug treatment, the use of 32P has been greatly reduced. Dr. Mihm pioneered the concept of pulsed dye laser (PDL) in combination with angiogenic inhibitors to improve the clinical efficacy of port wine stain (PWS) treatment. Moreover, he made seminal contributions to our understanding of the pathogenesis and spectrum of phenotypes of PWS lesions. The legacy of Martin C. Mihm extends to the entire world.

Background:Capillary malformation (CM) is a congenital vascular anomaly affecting the skin, mucosa, and brain, yet the understanding of its vascular pathogenesis remains limited. Methods:We applied spatial whole-transcriptome profiling (GeoMx) and gene set enrichment analysis within CM lesions at single vasculature level. Differentially expressed genes were validated by immunofluorescence staining. Phosphoproteomics was profiled to uncover lesion-wide phosphorylation sites on proteins. Single-cell RNA sequencing was performed on CM-derived induced pluripotent stem cells (iPSCs) to determine differentiation trajectories of lesional vascular lineages. In silico gene perturbation was used to predict candidate genes for modulating vascular pathological progression, followed by functional validation in CM iPSC-derived endothelial cells (ECs) using a Tet-on system. Results:A spatial transcriptomic atlas was constructed, and pathological landscape of individual CM vasculature was delineated. CM vessels exhibited hallmarks of endothelial-to-mesenchymal transition (EndMT), including disruption of adherens junctions (AJs), vascular identity transitions, and metabolic remodeling. Phosphoproteomics confirmed that differentially phosphorylated proteins were enriched in EndMT- and AJ-related pathways. Aberrant expression of venous transcriptional factor NR2F2 was observed in lesional ECs and correlated with progressive enlargement from capillaries to larger-caliber vessels containing multiple layers of smooth muscle cells (SMCs). In CM iPSCs, differentiation course yielded reduced ECs but increased SMCs. In silico knockout simulation predicted NR2F2 as a crucial regulator of facilitating SMC phenotype in CM. Consistently, enforced NR2F2 expression during iPSC differentiation suppressed endothelial markers while inducing SMC-associated genes. Conclusions:Single CM vasculature displays pathological hallmarks characterized by EndMT and AJ disruption, leading to progressive vascular remodeling. NR2F2 functions as a central regulatory factor orchestrating the acquisition of the SMC phenotype, thereby representing a potential therapeutic target in CM.

Capillary malformation (CM) is a congenital vascular anomaly that affects the skin, mucosa, eye, and brain. A major obstacle to mechanistic and drug screening studies for CM has been the lack of preclinical models. In this study, we established vascular organoids (VOs) generated through the self-assembly of vascular lineages of endothelial cells and smooth muscle cells differentiated from CM-induced pluripotent stem cells (iPSC). Within these VOs induced endothelial cells and smooth muscle cells organized into juxtapositions to form vascular branches. CM patient iPSC-derived VOs showed a higher density of endothelial and smooth muscle cell populations and greater vascular branch lengths as compared with VOs derived from iPSCs generated from healthy skin biopsies. Overall, this study represents the first disease-relevant VO model of CM, providing a valuable platform for future mechanistic studies and drug screening.

Cutaneous neurofibromas (cNF) appear commonly in neurofibromatosis type I (NF1) patients. cNFs usually appear in the skin at puberty and proliferate with increasing numbers and sizes throughout life. If cNFs can be detected and treated in their nascent stage, patient's quality of life can be improved. To detect early-stage cNF, we have employed spatial frequency domain imaging (SFDI) and optical coherence tomography (OCT). SFDI has been applied to screen large skin areas on eleven cNF subjects. Suspect lesions invisible to the unaided eye but detected using SFDI were imaged with OCT to observe lesion microstructure. Three lesions were biopsied to compare with SFDI and OCT images. Suspect nascent cNFs which are invisible to the unaided eye were detected as low optical scattering regions in all patients. Large area screening using SFDI confirmed scattering contrast between the suspect nascent cNF and the surrounding uninvolved skin. Abnormal disc-shaped structures with reduced scattering regions detected by SFDI were also observed in OCT cross-sections.

BACKGROUND:Port wine birthmark (PWB) is a congenital vascular malformation of the skin. Pulsed dye laser (PDL) is the "gold standard" for the treatment of PWB globally. Hematoporphyrin monomethyl ether (HMME or hemoporfin)-mediated photodynamic therapy (HMME-PDT) has emerged as the first choice for PWB treatment, particularly for young children, in many major hospitals in China during the past several decades. AIM:To evaluate whether HMME-PDT is superior to PDL by comparing the clinical efficacies of both modalities. METHOD:PubMed records were searched for all relevant studies of PWB treatment using PDL (1988-2023) or HMME-PDT (2007-2023). Patient characteristics and clinical efficacies were extracted. Studies with a quartile percentage clearance or similar scale were included. A mean color clearance index (CI) per study was calculated and compared among groups. An overall CI (C0), with data weighted by cohort size, was used to evaluate the final efficacy for each modality. RESULT:A total of 18 HMME-PDT studies with 3910 patients in China were eligible for inclusion in this analysis. Similarly, 40 PDL studies with 5094 patients from nine different countries were eligible for inclusion in this analysis. Over 58% of patients in the HMME-PDT studies were minors (<18 years old). A significant portion (21.3%) were young children (<3 years old). Similarly, 33.2% of patients in the PDL studies were minors. A small proportion (9.3%) was young children. The overall clearance rates for PDL were slightly, but not significantly, higher than those for HMME-PDT in cohorts with patients of all ages (C0, 0.54 vs. 0.48, p = 0.733), subpopulations with only minors (C0, 0.54 vs. 0.46, p = 0.714), and young children (C0, 0.67 vs. 0.50, p = 0.081). Regrettably, there was a lack of long-term data on follow-up evaluations for efficacy and impact of HMME-PDT on young children in general, and central nervous system development in particular, because their blood-brain barriers have a greater permeability as compared to adults. CONCLUSION:PDL shows overall albeit insignificantly higher clearance rates than HMME-PDT in patients of all ages; particularly statistical significance is nearly achieved in young children. Collectively, current evidence is insufficient to support HMME-PDT as the first choice of treatment of PWBs in young children given: (1) overall inferior efficacy as compared to PDL; (2) risk of off-target exposure to meningeal vasculature during the procedure; (3) administration of steriods for mitigation of side effects; -and (4) lack of long-term data on the potential impact of HMME on central nervous system development in young children.

Erythrocyte-derived optical microparticles containing near infrared (NIR) dyes such as indocyanine green ( ICG) present a promising platform for fluorescence imaging and laser treatment of abnormal vasculature, including port wine birthmarks. Herein, we have investigated the effects of blood type utilized in fabricating these microparticles, and the number density of the particles on their circulation time in mice by real-time NIR fluorescence imaging of the dermal vasculature. We find that the emission half-life of microparticles engineered from human O+ blood type increases by approximately two-fold as compared to those engineered from B+ blood type. Increasing the number density of the microparticles fabricated from O+ blood type from similar to 0.5 millions/mu l to 1.6 millions/mu l is associated with nearly a fourfold increase in the emission half-life of the particles. These findings emphasize the importance of blood type and number density in engineering erythrocyte-derived particles for clinical applications as treatment of PWBs.

Lesional induced pluripotent stem cell-derived endothelial cells can resemble pathological vascular phenotypes of port-wine birthmark (PWB). Our data demonstrate that multiple pathways, including Hippo and Wnt, NFκB, TNF, MAPK and cholesterol metabolism, are dysregulated. These data suggest new therapeutics can be developed to target such dysregulated pathways in the treatment of PWB.

Port Wine Birthmarks (PWBs) are a congenital vascular malformation on the skin, occurring in 1–3 per 1000 live births. We have recently generated PWB-derived induced pluripotent stem cells (iPSCs) as clinically relevant disease models. The metabolites associated with the pathological phenotypes of PWB-derived iPSCs are unknown, and so we aim to explore them in this study. Metabolites were separated by ultra-performance liquid chromatography and screened with electrospray ionization mass spectrometry. Orthogonal partial least-squares discriminant, multivariate, and univariate analyses were used to identify differential metabolites (DMs). KEGG analysis was used to determine the enrichment of metabolic pathways. A total of 339 metabolites was identified. There were 22 DMs, among which nine were downregulated—including sphingosine—and 13 were upregulated, including glutathione in PWB iPSCs, as compared to controls. Pathway enrichment analysis confirmed the upregulation of glutathione and the downregulation of sphingolipid metabolism in PWB-derived iPSCs as compared to normal ones. We next examined the expression patterns of the key molecules associated with glutathione metabolism in PWB lesions. We found that hypoxia-inducible factor 1α (HIF1α), glutathione S-transferase Pi 1 (GSTP1), γ-glutamyl transferase 7 (GGT7), and glutamate cysteine ligase modulatory subunit (GCLM) were upregulated in PWB vasculatures as compared to blood vessels in normal skin. Other significantly affected metabolic pathways in PWB iPSCs included pentose and glucuronate interconversions; amino sugar and nucleotide sugars; alanine, aspartate, and glutamate; arginine, purine, D-glutamine, and D-glutamate; arachidonic acid, glyoxylate, and dicarboxylate; nitrogen, aminoacyl-tRNA biosynthesis, pyrimidine, galactose, ascorbate, and aldarate; and starch and sucrose. Our data demonstrated that there were perturbations in sphingolipid and cellular redox homeostasis in PWB vasculatures, which could facilitate cell survival and pathological progression. Our data implied that the upregulation of glutathione could contribute to laser-resistant phenotypes in some PWB vasculatures.

1 Beck DB, Ferrada MA, Sikora KA et al. Somatic mutations in UBA1 and severe adult-onset autoinflammatory disease. N Engl J Med 2020; 383:2628–38. 2 van der Made CI, Potjewijd J, Hoogstins A et al. Adult-onset autoinflammation caused by mutations in UBA1: a Dutch case series of patients with VEXAS. J Allergy Clin Immunol 2022; 149(1):432–9. 3 Ferrada MA, Sikora KA, Luo Y et al. Somatic mutations in UBA1 define a distinct subset of relapsing polychondritis patients with VEXAS. Arthritis Rheumatol 2021; 73:1886–95. 4 Georgin-Lavialle S, Terrier B, Guedon AF et al. Further characterization of clinical and laboratory features in VEXAS syndrome: largescale analysis of a multicentre case series of 116 French patients. Br J Dermatol 2022; 186:564–74.

Objective: We retrospectively studied the clinical presentations and outcomes of endovascular management in a mixed pediatric and adult Klippel-Trenaunay syndrome (KTS) population at a single academic medical center. Methods: We performed a retrospective study of patients with KTS who had been referred for endovascular intervention after evaluation and diagnosis by a multidisciplinary team at a single academic medical center during a 10-year period. The patient demographics, areas affected, presenting symptoms, previous treatments, imaging modalities, endovascular treatment types, number of treatments, and complications were assessed. The technical and clinical success rates were calculated. Results: Twenty-six patients with suspected KTS were evaluated. Of these 26 patients, 20, aged 2 to 75 years, had been diagnosed with KTS using the International Society for the Study of Vascular Anomalies criteria and referred for endovascular management. The left lower extremity was affected most often. The presenting symptoms were pain (80%), edema (70%), bleeding (10%), numbness (25%), and claudication (25%). Of the 20 patients, 16 (80%) had undergone treatment of KTS before presenting to our institution. Magnetic resonance imaging and ultrasound (US) were the most common imaging modalities. Fifteen patients underwent 46 endovascular treatments during the study period. The treatments included 5 endovenous ablations only, 4 US-guided sclerotherapies with endovenous ablation, 5 US-guided sclerotherapies only, and 32 catheter-directed venograms with additional interventions. Localized intravascular coagulopathy was the only procedure-related complication and occurred in one patient after three treatments. The technical success rate was 97.8%, and the clinical success rate was 100%. Conclusions: Endovascular intervention is safe and effective for KTS patients for whom conservative management has failed. Pain and edema were the most common presenting symptoms. Presenting symptoms may be related to pathology of anomalous veins, orthotopic superficial veins or deep veins. Venous claudication can be present in those with KTS despite patency of the deep venous system. Magnetic resonance imaging and duplex US are frequently used modalities for venous assessment. The complications of endovascular treatment are rare but include localized intravascular coagulopathy.

ImportanceSturge-Weber syndrome (SWS) is a neurocutaneous syndrome involving the skin, brain, and eyes. Consensus recommendations for management are lacking.ObjectiveTo consolidate the current literature with expert opinion to make recommendations that will guide treatment and referral for patients with port-wine birthmarks (PWBs).Evidence ReviewIn this consensus statement, 12 nationally peer-recognized experts in dermatology with experience treating patients with SWS were assembled. Key topics and questions were formulated for each group and included risk stratification, optimum treatment strategies, and recommendations regarding light-based therapies. A systematic PubMed search was performed of English-language articles published between December 1, 2008, and December 1, 2018, as well as other pertinent studies identified by the expert panel. Clinical practice guidelines were recommended.FindingsTreatment of PWBs is indicated to minimize the psychosocial impact and diminish nodularity and potentially tissue hypertrophy. Better outcomes may be attained if treatments are started at an earlier age. In the US, pulsed dye laser is the standard for all PWBs regardless of the lesion size, location, or color. When performed by experienced physicians, laser treatment can be safe for patients of all ages. The choice of using general anesthesia in young patients is a complex decision that must be considered on a case-by-case basis.Conclusions and RelevanceThese recommendations are intended to help guide clinical practice and decision-making for patients with SWS and those with isolated PWBs and may improve patient outcomes.

Lymphatic malformations (LMs) are rare congenital anomalies. LMs are often refractory to standard treatments, including surgical resection, debulking, and sclerotherapy. Use of sildenafil, a phosphodiesterase-5 inhibitor, for treatment of pediatric LMs has been reported with demonstrated benefit to some patients. This case series reports treatment of three patients (aged 14-37 years) suffering from complicated or refractory LMs with a low-dose oral phosphodiesterase-5 inhibitor, resulting in significant clinical improvement.

Erythrocyte-based carriers can serve as theranostic platforms for delivery of imaging and therapeutic payloads. Engineering these carriers at micro- or nanoscales makes them potentially useful for broad clinical applications ranging from vascular diseases to tumor theranostics. Longevity of these carriers in circulation is important in delivering a sufficient amount of their payloads to the target. We have investigated the circulation dynamics of micro (∼4.95 μm diameter) and nano (∼91 nm diameter) erythrocyte-derived carriers in real time using near-infrared fluorescence imaging, and evaluated the effectiveness of such carrier systems in mediating photothermolysis of cutaneous vasculature in mice. Fluorescence emission half-lives of micro- and nanosized carriers in response to a single intravenous injection were ∼49 and ∼15 min, respectively. A single injection of microsized carriers resulted in a 3-fold increase in signal-to-noise ratio that remained nearly persistent over 1 h of imaging time. Our results also suggest that a second injection of the carriers 7 days later can induce a transient inflammatory response, as manifested by the apparent leakage of the carriers into the perivascular tissue. The administration of the carriers into the mice vasculature reduced the threshold laser fluence to induce photothermolysis of blood vessels from >65 to 20 J/cm2. We discuss the importance of membrane physicochemical and mechanical characteristics in engineering erythrocyte-derived carriers and considerations for their clinical translation.

Background and ObjectivesPort wine stain (PWS) is a congenital vascular malformation of the human skin. Laser is the treatment of choice for PWS. Laser‐resistant PWS is one crucial factor accounting for inadequate treatment outcome, which needs to be fully characterized. This study aims to quantitatively characterize the morphology of laser‐resistant PWS blood vessels in the upper papillary dermis using in vivo reflectance confocal microscopy (RCM).Study Design/Materials and MethodsA total of 42 PWS subjects receiving laser treatment from August 2016 through July 2018 were enrolled into this study. Thirty‐three subjects had facial PWS; nine had extremity PWS. All subject's PWS received multiplex 585/1,064 nm laser treatment. RCM images were taken before and after treatment. The density, diameter, blood flow, and depth of PWS blood vessels were analyzed.ResultsWe found 44.4% PWS on the extremities (four out of nine subjects) were laser‐resistant, which was significantly higher (P < 0.001) when compared with those PWS on the face (15.2%, 5 out of 33 subjects). The laser‐resistant facial PWS blood vessels had significantly higher blood flow (1.35 ± 0.26 U vs. 0.89 ± 0.22 U, P < 0.001), larger blood vessel diameters (109.60 ± 18.24 µm vs. 84.36 ± 24.04 µm, P = 0.033) and were located deeper in the skin (106.01 ± 13.87 µm vs. 87.82 ± 12.57 µm, P < 0.001) in the skin when compared with laser‐responsive PWS on the face. The average PWS blood vessel density (17.01 ± 4.63/mm2 vs. 16.61 ± 4.44/mm2, P = 0.857) was not correlated to the laser resistance.ConclusionsLaser‐resistant PWS blood vessels had significantly higher blood flow, larger diameters, and were located deeper in the skin. RCM can be a valuable tool for a prognostic evaluation on laser‐resistant lesions before treatment, thereby providing guidance for tailored laser treatment protocols, which may improve the therapeutic outcome. The limitations for this study include relative small sample size and acquisitions of different blood vessels before and after 2 months of treatment. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

INTRODUCTION:Port wine stain (PWS) is characterized as a progressive dilatation of immature venule-like vasculatures which result from differentiation-impaired endothelial cells. In this study, we aimed to identify the major biological pathways accounting for the pathogenesis of PWS.METHODS:Sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) was used to identify differentially expressed proteins in PWS lesions, followed by confirmative studies with immunohistochemistry, immunoblot and transmission electron microscopy (TEM).RESULTS:107 out of 299 identified proteins showed differential expressions in PWS lesions as compared to normal skin, mainly involving the functions of biosynthesis, membrane trafficking, cytoskeleton and cell adhesion/migration. The confirmative studies showed that expressions of membrane trafficking/exocytosis related proteins such as VAT1, IQGAP1, HSC70, clathrin, perlecan, spectrin α1 and GDIR1 were significantly increased in PWS blood vessels as compared to normal ones; while collagen subtypes 6A1 and 6A3 were decreased in PWS skin. Furthermore, TEM studies showed there is a significant upregulation of extracellular vesicle exocytosis from PWS blood vessels as compared to control.CONCLUSIONS:The biological process of membrane trafficking and exocytosis is enhanced in PWS blood vessels. Our results imply that the extracellular vesicles released by lesional endothelial cells may act as potential intercellular signaling mediators to contribute to the pathogenesis of PWS.

Pulsed dye laser irradiation in the wavelength range of 585 to 600 nm is currently the gold standard for treatment of port-wine stains (PWSs). However, this treatment method is often ineffective for deeply seated blood vessels and in individuals with moderate to heavy pigmentation. Use of optical particles doped with the FDA-approved near-infrared (NIR) absorber, indocyanine green (ICG), can potentially provide an effective method to overcome these limitations. Herein, we theoretically investigate the effectiveness of particles derived from erythrocytes, which contain ICG, in mediating photothermal destruction of PWS blood vessels. We refer to these particles as NIR erythrocyte-derived transducers (NETs). Our theoretical model consists of a Monte Carlo algorithm to estimate the volumetric energy deposition, a finite elements approach to solve the heat diffusion equation, and a damage integral based on an Arrhenius relationship to quantify tissue damage. The model geometries include simulated PWS blood vessels as well as actual human PWS blood vessels plexus obtained by the optical coherence tomography. Our simulation results indicate that blood vessels containing micron-or nano-sized NETs and irradiated at 755 nm have higher levels of photothermal damage as compared to blood vessels without NETs irradiated at 585 nm. Blood vessels containing micron-sized NETs also showed higher photothermal damage than blood vessels containing nano-sized NETs. The theoretical model presented can be used in guiding the fabrication of NETs with patient-specific optical properties to allow for personalized treatment based on the depth and size of blood vessels as well as the pigmentation of the individual's skin. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.