The Skin of Color Society's Meeting the Challenge Summit, 2022: Diversity in Dermatology Clinical Trials Proceedings

Importance

Clinical trials remain the cornerstone for determining the safety and efficacy of an intervention. A diverse participant pool in dermatology clinical trials is critical to ensure that results are generalizable among the patient population who will ultimately depend on the efficacy of the intervention. The Skin of Color Society hosted the inaugural Meeting the Challenge Summit: Diversity in Dermatology Clinical Trials in Washington, DC, from June 10 to 11, 2022. The summit was an interactive and collaborative effort to advance discussions regarding the need for broader inclusion of racial and ethnic minority patients in dermatology clinical trials.

Observations

The summit focused on 3 principal areas: (1) understanding the current clinical trials landscape; (2) breaking down patient, clinician, industry, and regulatory barriers; and (3) effecting change through a diversity-focused strategy. The program hosted thought-provoking panel talks and discussions with various stakeholder groups, including a keynote presentation from the family of Henrietta Lacks.

Conclusions and Relevance

Panel discussions and insightful presentations from physicians, industry leaders, community trailblazers, and patients fostered new collaborations. The summit provided recommendations and suggested strategies for future initiatives designed to increase the representation of minority individuals in dermatology clinical trials.

Punctate Palmoplantar Keratoderma: A Case Report

Palmoplantar keratoderma (PPK) is an umbrella term for a group of heterogeneous disorders, acquired or inherited, that are characterized by hyperkeratosis of palmar and/or plantar surfaces. Punctate PPK (PPPK) has been shown to have an autosomal dominant pattern of inheritance. It is linked with two loci on chromosomes 8q24.13-8q24.21 and 15q22-15q24. In type 1 PPPK, also known as Buschke-Fischer-Brauer disease, loss-of-function mutations in either the AAGAB or the COL14A1 genes have been associated with the disorder. We report here the clinical and genetic features of a patient with findings most consistent with type 1 PPPK.

A severe presentation of acute generalized exanthematous pustulosis with non-infectious circulatory shock in an adolescent

We present a severe case of acute generalized exanthematous pustulosis (AGEP) secondary to trimethoprim-sulfamethoxazole complicated by non-infectious circulatory shock in a 16-year-old boy. Hemodynamic instability has been reported as a complication of AGEP in adults, but is rarely observed in pediatric patients. The patient we present demonstrated characteristic cutaneous findings of AGEP including isolated non-follicular, sterile pustules on a background of erythema with involvement at intertriginous areas and subsequently developed non-infectious circulatory shock. This case expands the spectrum of possible clinical presentations for AGEP in pediatric patients.

Biallelic variants in RNU12 cause CDAGS syndrome

CDAGS Syndrome is a rare congenital disorder characterized by Craniosynostosis, Delayed closure of the fontanelles, cranial defects, clavicular hypoplasia, Anal and Genitourinary malformations, and Skin manifestations. We performed whole exome and Sanger sequencing to identify the underlying molecular cause in five patients with CDAGS syndrome from four distinct families. Whole exome sequencing revealed biallelic rare variants that disrupt highly conserved nucleotides within the RNU12 gene. RNU12 encodes a small nuclear RNA that is a component of the minor spliceosome and is essential for minor intron splicing. Targeted sequencing confirmed allele segregation within the four families. All five patients shared the same rare mutation NC_000022.10:g.43011402C>T, which alters a highly conserved nucleotide within the precursor U12 snRNA 3' extension. Each of them also carried a rare variant on the other allele that either disrupts the secondary structure or the Sm binding site of the RNU12 snRNA. Whole transcriptome sequencing analysis of lymphoblastoid cells identified 120 differentially expressed genes, and differential alternative splicing analysis indicated there was an enrichment of alternative splicing events in the patient. These findings provide evidence of the involvement of RNU12 in craniosynostosis, anal and genitourinary patterning, and cutaneous disease.

Human cutaneous neurofibroma matrisome revealed by single-cell RNA sequencing

Neurofibromatosis Type I (NF1) is a neurocutaneous genetic syndrome characterized by a wide spectrum of clinical presentations, including benign peripheral nerve sheath tumor called neurofibroma. These tumors originate from the Schwann cell lineage but other cell types as well as extracellular matrix (ECM) in the neurofibroma microenvironment constitute the majority of the tumor mass. In fact, collagen accounts for up to 50% of the neurofibroma's dry weight. Although the presence of collagens in neurofibroma is indisputable, the exact repertoire of ECM genes and ECM-associated genes (i.e. the matrisome) and their functions are unknown. Here, transcriptome profiling by single-cell RNA sequencing reveals the matrisome of human cutaneous neurofibroma (cNF). We discovered that classic pro-fibrogenic collagen I myofibroblasts are rare in neurofibroma. In contrast, collagen VI, a pro-tumorigenic ECM, is abundant and mainly secreted by neurofibroma fibroblasts. This study also identified potential cell type-specific markers to further elucidate the biology of the cNF microenvironment.

A Review of Current Keloid Management: Mainstay Monotherapies and Emerging Approaches

Commonly affecting those with skin of color, keloids are an aberrant wound response that leads to wound tissue expanding above and beyond the original cutaneous injury. Keloids are notoriously and particularly difficult to treat because of their tendency to recur after excision. The current standard of care is intralesional steroid (triamcinolone acetonide). However, because no therapy has yet proven to be fully curative, keloid treatments have expanded to include a number of options, from injections to multimodal approaches. This review details current treatment of keloids with injections (bleomycin, verapamil, hyaluronic acid and hyaluronidase, botulinum toxin, and collagenase), cryotherapy, laser, radiofrequency ablation, radiation, extracorporeal shockwave therapy, pentoxifylline, and dupilumab.

Plasma Angiotensin-converting Enzyme Levels in Patients With Keloids and/or Hypertension

INTRODUCTION

Keloidal scarring is associated with hypertension and its pathogenesis remains poorly understood. The role of angiotensin-converting enzyme (ACE) in both hypertensive and fibrotic conditions suggests ACE may be a common mechanism for the pathogenesis of both hypertension and keloids.

OBJECTIVE

This paper aims to investigate the possible underlying role of ACE in keloid pathogenesis.

MATERIALS AND METHODS

Plasma samples were collected from participants with and without keloids. Enzyme-linked immunosorbent assays were then performed to determine ACE levels in the plasma samples. The plasma ACE levels of patients with and without keloid scarring were compared, while controlling for hypertension.

RESULTS

The 78 samples (39 keloid participants, 39 controls) were divided into 4 cohorts of either 18 (hypertensive) or 21 (normotensive) participants. The mean ± standard deviation ACE levels were 77.9 ± 31.2 ng/mL for the hypertensive keloid group (n = 18), 69.2 ± 18.8 ng/mL for the normotensive keloid group (n = 21), 72.7 ± 21.5 ng/mL for the hypertensive control group (n = 18), and 77.6 ± 18.5 ng/mL for the normotensive control group (n = 21). No significant differences in the mean plasma ACE levels were found between any of the 4 groups.

CONCLUSIONS

Although the data showed no significant correlation between plasma ACE levels, keloids, and hypertension, additional studies may be pursued to determine the possible underlying role of ACE in keloid pathogenesis.

Current Understanding of the Genetic Causes of Keloid Formation

Keloids are an exuberant response to cutaneous wound healing. Several lines of evidence suggest that keloid scarring is influenced by genetic factors. This review will discuss our current understanding of genetic influences on keloidal scarring via familial inheritance patterns; ethnic differences in prevalence; syndromes with keloid occurrence; linkage analysis, genome-wide association studies, and admixture mapping studies; transforming growth factor beta and p53 variant studies; and human leukocyte antigen polymorphisms.

Prescription-level factors associated with primary nonadherence to dermatologic medications

PURPOSE

To analyze factors associated with primary nonadherence to dermatologic medications and study whether prescription-level factors are associated with primary nonadherence.

MATERIALS AND METHODS

A retrospective review of medical records of new dermatology patients from January 2011 to December 2013 at a single urban safety-net hospital outpatient dermatology clinic with a closed pharmacy system.

RESULTS

A total of 4307 prescriptions were written for 2490 patients. The overall primary nonadherence rate was 24.7%. The most prescribed medication classes in order of frequency were topical corticosteroids, topical antibiotics, topical retinoids, oral antibiotics, and topical antifungals. After multivariable adjustment for patient, provider, and prescription characteristics, when compared to topical corticosteroids, topical antibiotics, oral antifungals, and oral antivirals were less likely to be filled (RR 0.9 [95% CI, 0.84-0.95]), (RR 0.69 [95% CI, 0.59-0.81]), and (RR 0.65 [95% CI, 0.46-0.93]), respectively. Conversely, topical vitamin D analogs, oral immunomodulators, and oral retinoids were more likely to be filled (RR 1.15 [95% CI, 1.02-1.28]), (RR 1.11 [95% CI, 1.04-1.19]), and (RR 1.15 [95% CI, 1.04-1.27]), respectively.

CONCLUSIONS

Medication class or administration route may be associated with increased risk of nonadherence, and identifying these factors is important in considering ways to reduce primary nonadherence rates in dermatology.

Primary milia localized to the vulva

Multiple primary milia were found on the vulva of a 52-year-old woman who was referred to the dermatology clinic by her gynecologist. These lesions are commonly distributed on the face and rarely occur in this location without antecedent trauma. This report demonstrates the unique presentation of primary milia in the genital region and explores the diagnostic features and treatment methods of these lesions.

Painful toe ulcers

The patient didn't have diabetes, and wound and blood cultures were negative for infection. So what was causing these recurrent ulcers?

In vivo analysis of Wnt signaling in bone

Bone remodeling requires osteoblasts and osteoclasts working in concert to maintain a constant bone mass. The dysregulation of signaling pathways that affect osteoblast or osteoclast differentiation or function leads to either osteopenia or high bone mass. The discovery that activating and inactivating mutations in low-density lipoprotein receptor-related protein 5, a putative Wnt coreceptor, led to high bone mass and low bone mass in human beings, respectively, generated a tremendous amount of interest in the possible role of the Wnt signaling pathway in the regulation of bone remodeling. A number of mouse models have been generated to study a collection of Wnt signaling molecules that have been identified as regulators of bone mass. These mouse models help establish the canonical Wnt signaling pathway as a major regulator of chondrogenesis, osteoblastogenesis, and osteoclastogenesis. This review will summarize these advances.

Canonical Wnt Signaling in Osteoblasts Is Required for Osteoclast Differentiation

Inactivation of Lrp5, a gene encoding a likely Wnt co-receptor, results in low bone mass (osteopenia) by decreasing bone formation, suggesting that Wnt signaling in osteoblasts regulates bone formation. Here we show that Tcf1 and Tcf4 are expressed in osteoblasts during development and after birth; stabilization of beta-catenin, an essential component of canonical Wnt signaling, in differentiated osteoblasts results in high bone mass while its deletion from differentiated osteoblasts leads to osteopenia. Histological analysis showed that these mutations affect bone resorption. Cellular and molecular studies showed that beta-catenin together with TCF proteins regulates in osteoblasts the expression of Osteoprotegerin, a major inhibitor of osteoclast differentiation. These findings demonstrate that, in differentiated osteoblasts, beta-catenin and presumably Wnt signaling are negative regulators of osteoclast differentiation; thus they broaden our knowledge about functions that Wnt proteins may have at various stages of skeletogenesis.

Molecular bases of the regulation of bone remodeling by the canonical Wnt signaling pathway

Osteoporosis is a common, prevalent, and debilitating condition, particularly in postmenopausal women. Genetics play a major role in determining peak bone mass and fracture risk, but few genes have been demonstrated conclusively to be involved, much less the signaling pathways with which they are affiliated. The identification of mutations in the gene Lrp5, a Wnt coreceptor, as the cause for both osteoporotic and high-bone mass disorders implicated the canonical Wnt signaling pathway in bone mass regulation. Since Lrp5, other Wnt components have been identified as being regulators of bone mass, and Wnt target genes affecting bone homeostasis have begun to be elucidated. This chapter looks at the various components of the canonical Wnt signaling pathway and the data indicating that this pathway plays a major role in the control of both bone formation and bone resorption, the two key aspects of bone remodeling.

WNT7b mediates macrophage-induced programmed cell death in patterning of the vasculature

Macrophages have a critical role in inflammatory and immune responses through their ability to recognize and engulf apoptotic cells. Here we show that macrophages initiate a cell-death programme in target cells by activating the canonical WNT pathway. We show in mice that macrophage WNT7b is a short-range paracrine signal required for WNT-pathway responses and programmed cell death in the vascular endothelial cells of the temporary hyaloid vessels of the developing eye. These findings indicate that macrophages can use WNT ligands to influence cell-fate decisions--including cell death--in adjacent cells, and raise the possibility that they do so in many different cellular contexts.

Canonical Wnt signaling in differentiated osteoblasts controls osteoclast differentiation

Inactivation of beta-catenin in mesenchymal progenitors prevents osteoblast differentiation; inactivation of Lrp5, a gene encoding a likely Wnt coreceptor, results in low bone mass (osteopenia) by decreasing bone formation. These observations indicate that Wnt signaling controls osteoblast differentiation and suggest that it may regulate bone formation in differentiated osteoblasts. Here, we study later events and find that stabilization of beta-catenin in differentiated osteoblasts results in high bone mass, while its deletion from differentiated osteoblasts leads to osteopenia. Surprisingly, histological analysis showed that these mutations primarily affect bone resorption rather than bone formation. Cellular and molecular studies showed that beta-catenin together with TCF proteins regulates osteoblast expression of Osteoprotegerin, a major inhibitor of osteoclast differentiation. These findings demonstrate that beta-catenin, and presumably Wnt signaling, promote the ability of differentiated osteoblasts to inhibit osteoclast differentiation; thus, they broaden our knowledge of the functions Wnt proteins have at various stages of skeletogenesis.

Reversible skeletal abnormalities in gamma-glutamyl transpeptidase-deficient mice

Gamma-glutamyl transpeptidase (GGT) is a widely distributed ectopeptidase responsible for the degradation of glutathione in the gamma-glutamyl cycle. This cycle is implicated in the metabolism of cysteine, and absence of GGT causes a severe intracellular decrease in this amino acid. GGT-deficient (GGT-/-) mice have multiple metabolic abnormalities and are dwarf. We show here that this latter phenotype is due to a decreased of the growth plate cartilage total height resulting from a proliferative defect of chondrocytes. In addition, analysis of vertebrae and tibiae of GGT-/- mice revealed a severe osteopenia. Histomorphometric studies showed that this low bone mass phenotype results from an increased osteoclast number and activity as well as from a marked decrease in osteoblast activity. Interestingly, neither osteoblasts, osteoclasts, nor chondrocytes express GGT, suggesting that the observed defects are secondary to other abnormalities. N-acetylcysteine supplementation has been shown to reverse the metabolic abnormalities of the GGT-/- mice and in particular to restore the level of IGF-1 and sex steroids in these mice. Consistent with these previous observations, N-acetylcysteine treatment of GGT-/- mice ameliorates their skeletal abnormalities by normalizing chondrocytes proliferation and osteoblastic function. In contrast, resorbtion parameters are only partially normalized in GGT-/- N-acetylcysteine-treated mice, suggesting that GGT regulates osteoclast biology at least partly independently of these hormones. These results establish the importance of cysteine metabolism for the regulation of bone remodeling and longitudinal growth.

Cbfa1-independent decrease in osteoblast proliferation, osteopenia, and persistent embryonic eye vascularization in mice deficient in Lrp5, a Wnt coreceptor

The low-density lipoprotein receptor-related protein (Lrp)-5 functions as a Wnt coreceptor. Here we show that mice with a targeted disruption of Lrp5 develop a low bone mass phenotype. In vivo and in vitro analyses indicate that this phenotype becomes evident postnatally, and demonstrate that it is secondary to decreased osteoblast proliferation and function in a Cbfa1-independent manner. Lrp5 is expressed in osteoblasts and is required for optimal Wnt signaling in osteoblasts. In addition, Lrp5-deficient mice display persistent embryonic eye vascularization due to a failure of macrophage-induced endothelial cell apoptosis. These results implicate Wnt proteins in the postnatal control of vascular regression and bone formation, two functions affected in many diseases. Moreover, these features recapitulate human osteoporosis-pseudoglioma syndrome, caused by LRP5 inactivation.

Histologic evaluation of bone inductive proteins complexed with coralline hydroxylapatite in an extraskeletal site of the rat

The purpose of this histologic and biochemical study was to assess the osteogenic potential of bone inductive proteins complexed with coralline hydroxylapatite as the carrier vehicle after implantation in an extraskeletal site of the rat. Inductive proteins were extracted from bovine demineralized bone. Implants were placed in 16 male, 3-month old Long-Evans rats (200-300 grams), using paired subcutaneous sites overlying the ventral thorax. There were four experimental groups, with eight implants per group. These included hydroxylapatite alone (HA), hydroxylapatite with inductive protein (HA + P), inactive demineralized bone matrix with (IBM + P), and without inductive protein (IBM). All implants were harvested at 21 days. Findings indicate a lack of osteogenic potential in groups HA, HA + P, and IBM. However, when HA and HA + P were compared, there was a 79% increase in standardized field mean nuclear point counts in the HA + P group. Also, compared to the other three implant groups, controls of IBM + P histomorphometrically showed chondroid bone formation and increased alkaline phosphatase activity. In this model system it may be concluded that with a composite system of coralline hydroxylapatite and bovine-derived inductive protein, bone formation was not seen; positive controls consisting of IBM + P demonstrated a statistically significant increase in AP activity with corresponding histologic evidence of bone formation.