Therapeutic TNF Inhibitors Exhibit Differential Levels of Efficacy in Accelerating Cutaneous Wound Healing.

Adalimumab but neither etanercept nor certolizumab-pegol has been reported to induce a wound-healing profile in vitro by regulating macrophage differentiation and matrix metalloproteinase expression, which may underlie the differences in efficacy between various TNF-α inhibitors in impaired wound healing in patients with hidradenitis suppurativa, a chronic inflammatory skin disease. To examine and compare the efficacy of various TNF inhibitors in cutaneous wound healing in vivo, a human TNF knock-in Leprdb/db mouse model was established to model the impaired cutaneous wound healing as seen in hidradenitis suppurativa. The vehicle group exhibited severe impairments in cutaneous wound healing. In contrast, adalimumab significantly accelerated healing, confirmed by both histologic assessment and a unique healing transcriptional profile. Moreover, adalimumab and infliximab showed similar levels of efficacy, but golimumab was less effective, along with etanercept and certolizumab-pegol. In line with histologic assessments, proteomics analyses from healing wounds exposed to various TNF inhibitors revealed distinct and differential wound-healing signatures that may underlie the differential efficacy of these inhibitors in accelerating cutaneous wound healing. Taken together, these data revealed that TNF inhibitors exhibited differential levels of efficacy in accelerating cutaneous wound healing in the impaired wound-healing model in vivo.

Importance of PLD2 in an IL-23 driven psoriasiform dermatitis model and potential link to human psoriasis.

Phospholipase D2 (PLD2), a major isoform of the PLD family, has been reported to regulate inflammatory responses. Thus far, the relevance of PLD2 in psoriasis, an inflammatory skin disease, has not been explored. In the current study, we examined PLD2 expression in the skin of psoriasis patients and the role of PLD2 in an interleukin (IL)-23-induced mouse model of psoriasiform dermatitis. Both in situ hybridization and bulk RNA sequencing showed PLD2 gene expression is significantly higher in lesional relative to non-lesional skin of psoriasis patients or the skin of healthy subjects. PLD2 expression is also enriched in residual lesions from patients on biologic therapies. Murine in vivo studies showed that PLD2 deficiency significantly reduced psoriasiform inflammation in IL-23-injected ears, as reflected by decreases in ear thickness, expression of defensin beta 4A and the S100 calcium binding protein A7A, macrophage infiltrate, and expression of CXCL10 and IL-6. However, the expression of type 17 cytokines, IL-17A and IL-17F, were not reduced. Dual knockout of PLD1 and PLD2 offered little additional protection compared to PLD2 knockout alone in the IL-23 model. In addition, pharmacological inhibition with a pan-PLD1/PLD2 inhibitor also suppressed IL-23-induced psoriasiform dermatitis. Bone-marrow-derived macrophages from wild type (WT) and PLD2 knockout (KO) mice exhibited little difference in viability and sensitivity to lipopolysaccharide and/or interferon gamma, or resiquimod (R848). PLD2 deficiency did not alter the differentiation and function of Th17 cells in an ex vivo study with splenocytes isolated from WT and PLD2 KO mice. Overall, these data suggest that PLD2 may play a role in the pathophysiology of psoriasis. Reducing macrophage infiltrate and cytokine/chemokine production might contribute to an anti-inflammatory effect observed in PLD2 knockout mice. Further studies are required to better understand the mechanisms by which PLD2 contributes to skin lesions in psoriasis patients and psoriasiform dermatitis models.

Targeting the NLRP3 inflammasome reduces inflammation in hidradenitis suppurativa skin.

BACKGROUND: Treatment for the debilitating disease hidradenitis suppurativa (HS) is inadequate in many patients. Despite an incidence of approximately 1%, HS is often under-recognized and underdiagnosed, and is associated with a high morbidity and poor quality of life. OBJECTIVES: To gain a better understanding of the pathogenesis of HS, in order to design new therapeutic strategies. METHODS: We employed single-cell RNA sequencing to analyse gene expression in immune cells isolated from involved HS skin vs. healthy skin. Flow cytometry was used to quantify the absolute numbers of the main immune populations. The secretion of inflammatory mediators from skin explant cultures was measured using multiplex and enzyme-linked immunosorbent assays. RESULTS: Single-cell RNA sequencing analysis identified a significant enrichment in the frequency of plasma cells, T helper (Th) 17 cells and dendritic cell subsets in HS skin, and the immune transcriptome was distinct and more heterogeneous than healthy skin. Flow cytometry revealed significantly increased numbers of T cells, B cells, neutrophils, dermal macrophages and dendritic cells in HS skin. Genes and pathways associated with Th17 cells, interleukin (IL)-17, IL-1ß and the NLRP3 inflammasome were enhanced in HS skin, particularly in samples with a high inflammatory load. Inflammasome constituent genes principally mapped to Langerhans cells and a subpopulation of dendritic cells. The secretome of HS skin explants contained significantly increased concentrations of inflammatory mediators, including IL-1ß and IL-17A, and culture with an NLRP3 inflammasome inhibitor significantly reduced the secretion of these, as well as other, key mediators of inflammation. CONCLUSIONS: These data provide a rationale for targeting the NLRP3 inflammasome in HS using small-molecule inhibitors that are currently being tested for other indications.

Noninvasive Tape-Stripping with High-Resolution RNA Profiling Effectively Captures a Preinflammatory State in Nonlesional Psoriatic Skin.

Tape stripping is a minimally invasive, nonscarring method that can be utilized to assess gene expression in the skin but is infrequently used given technical constraints. By comparing different tape stripping technologies and full-thickness skin biopsy results of lesional and nonlesional psoriatic skin from the same patients, we demonstrate that tape stripping with optimized high-resolution transcriptomic profiling can be used to effectively assess and characterize inflammatory responses in the skin. Upon comparison with single-cell RNA-sequencing data from psoriatic full-thickness skin biopsies, we illustrate that tape-stripping efficiently captures the transcriptome of the upper layers of the epidermis with sufficient resolution to assess the molecular components of the feed-forward immune amplification pathway in psoriasis. Notably, nonlesional psoriatic skin sampled by tape stripping demonstrates activated, proinflammatory changes when compared to healthy control skin, suggesting a prepsoriatic state, which is not captured on full-thickness skin biopsy transcriptome profiling. This work illustrates an approach to assess inflammatory response in the epidermis by combining noninvasive sampling with high throughput RNA-sequencing, providing a foundation for biomarker discoveries and mechanism of action studies for inflammatory skin conditions.

Phospholipase A2 enzymes represent a shared pathogenic pathway in psoriasis and pityriasis rubra pilaris.

Altered epidermal differentiation along with increased keratinocyte proliferation is a characteristic feature of psoriasis and pityriasis rubra pilaris (PRP). However, despite this large degree of overlapping clinical and histologic features, the molecular signatures these skin disorders share are unknown. Using global transcriptomic profiling, we demonstrate that plaque psoriasis and PRP skin lesions have high overlap, with all differentially expressed genes in PRP relative to normal skin having complete overlap with those in psoriasis. The major common pathway shared between psoriasis and PRP involves the phospholipases PLA2G2F, PLA2G4D, and PLA2G4E, which were found to be primarily expressed in the epidermis. Gene silencing each of the 3 PLA2s led to reduction in immune responses and epidermal thickness both in vitro and in vivo in a mouse model of psoriasis, establishing their proinflammatory roles. Lipidomic analyses demonstrated that PLA2s affect mobilization of a phospholipid-eicosanoid pool, which is altered in psoriatic lesions and functions to promote immune responses in keratinocytes. Taken together, our results highlight the important role of PLA2s as regulators of epidermal barrier homeostasis and inflammation, identify PLA2s as a shared pathogenic mechanism between PRP and psoriasis, and as potential therapeutic targets for both diseases.

Histologic progression of acne inversa/hidradenitis suppurativa: Implications for future investigations and therapeutic intervention.

Since first recognized in 1839, the pathogenesis of acne inversa (AI) has undergone repeated revisions. Although there is agreement that AI involves occlusion of hair follicles with subsequent inflammation and the formation of tracts, the histologic progression of this disease still requires refinement. The objective of this study was to examine the histologic progression of AI based on the examination of a large cohort of punch biopsies and excisional samples that were examined first by hematoxylin and eosin staining. The most informative of these samples were step-sectioned and stained by immunohistochemistry for epithelial and inflammatory markers. Based on this examination, the following observations were made: 1) AI arises from the epithelium of the infundibulum of terminal and vellus hairs; 2) These form cysts and epithelial tendrils that extend into soft tissue; 3) Immunohistochemical staining demonstrates the epithelium of AI is disordered with infundibular and isthmic differentiation and de novo expression of stem cell markers; 4) The inflammatory response in AI is heterogeneous and largely due to cyst rupture. The conclusions of this investigation were that AI is an epithelial-driven disease caused by infiltrative, cyst forming tendrils and most of the inflammation is due to cyst rupture and release of cornified debris and bacteria. Cyst rupture often occurs below the depths of punch biopsy samples indicating their use for analysis may give an incomplete picture of the disease. Finally, our data suggest that unless therapies inhibit tendril development, it is unlikely they will cause prolonged treatment-induced remission in AI.

Immunopathogenesis of hidradenitis suppurativa and response to anti-TNF-α therapy.

Hidradenitis suppurativa (HS) is a highly prevalent, morbid inflammatory skin disease with limited treatment options. The major cell types and inflammatory pathways in skin of patients with HS are poorly understood, and which patients will respond to TNF-α blockade is currently unknown. We discovered that clinically and histologically healthy appearing skin (i.e., nonlesional skin) is dysfunctional in patients with HS with a relative loss of immune regulatory pathways. HS skin lesions were characterized by quantitative and qualitative dysfunction of type 2 conventional dendritic cells, relatively reduced regulatory T cells, an influx of memory B cells, and a plasma cell/plasmablast infiltrate predominantly in end-stage fibrotic skin. At the molecular level, there was a relative bias toward the IL-1 pathway and type 1 T cell responses when compared with both healthy skin and psoriatic patient skin. Anti-TNF-α therapy markedly attenuated B cell activation with minimal effect on other inflammatory pathways. Finally, we identified an immune activation signature in skin before anti-TNF-α treatment that correlated with subsequent lack of response to this modality. Our results reveal the fundamental immunopathogenesis of HS and provide a molecular foundation for future studies focused on stratifying patients based on likelihood of clinical response to TNF-α blockade.

Persistence of Inflammatory Phenotype in Residual Psoriatic Plaques in Patients on Effective Biologic Therapy.

Many psoriasis patients treated with biologics do not achieve total skin clearance. These patients possess residual plaques despite ongoing biologic treatment. To elucidate mechanisms of plaque persistence despite overall good drug response, we studied 50 subjects: psoriasis patients with residual plaques treated with one of three different biologics, untreated patients, and healthy controls. Skin biopsies from all subjects were characterized using three methods: mRNA expression, histology, and FACS of hematopoietic skin cells. Although all three methods provided evidence of drug effect, gene expression analysis revealed the persistence of key psoriasis pathways in treated plaques, including granulocyte adhesion and diapedesis, T helper type17 activation pathway, and interferon signaling with no novel pathways emerging. Focal decreases in parakeratosis and keratinocyte proliferation and differential reduction in IL-17 producing CD103- T cells, but no change in CD103+ tissue-resident memory T cells were observed. Of note, antitumor necrosis factor increased the interferon signaling pathway already present. Interestingly mast cells were the dominant source of IL-22 in all psoriasis subjects. These data suggest that while subtle differences can be observed in drug-treated plaques, underlying biologic mechanisms are similar to those present in untreated psoriatic lesions.

Synaptic structural protein dysfunction leads to altered excitation inhibition ratios in models of autism spectrum disorder.

Genetics is believed to play a key role in the development of Autism Spectrum Disorder (ASD) and a plethora of potential candidate genes have been identified by genetic characterization of patients, their family members and controls. To make sense of this information investigators have searched for common pathways and downstream properties of neural networks that are regulated by these genes. For instance, several candidate genes encode synaptic proteins, and one hypothesis that has emerged is that disruption of the synaptic excitation and inhibition (E/I) balance would destabilize neural processing and lead to ASD phenotypes. Some compelling evidence for this has come from the analyses of mouse and culture models with defects in synaptic structural proteins, which influence several aspects of synapse biology and is the subject of this review. Remaining challenges include identifying the specifics that distinguish ASD from other psychiatric diseases and designing more direct tests of the E/I balance hypothesis.

Multidisciplinary cancer care: development of an infectious diseases physician assistant workforce at a comprehensive cancer center.

The authors outline the process through which the infectious diseases department at The M. D. Anderson Cancer Center successfully integrated physician assistants into patient care services, as judged by an overall increase in departmental productivity, broadened patient care coverage, and physician satisfaction with midlevel services.

QW-1624F2-2, a synthetic analogue of 1,25-dihydroxyvitamin D3, enhances the response to other deltanoids and suppresses the invasiveness of human metastatic breast tumor cells.

The enzyme 24-hydroxylase, also known as CYP24, metabolizes 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] and is an established marker of vitamin D activity. Our studies evaluated the influence of a low-calcemic 1,25(OH)(2)D(3) analogue, QW-1624F2-2 (QW), on the regulation of CYP24 expression in MKL-4 cells, a metastatic mammary tumor cell model. 1,25(OH)(2)D(3) and its analogue, EB 1089, stimulated CYP24 induction at both protein and transcript levels. In contrast, QW failed to produce a sustained stimulation of CYP24, due, in large part, to a reduction in the stability of the CYP24 message. QW enhanced the capacity of 1,25(OH)(2)D(3) and EB 1089 to inhibit tumor cell proliferation by approximately 2-fold. QW also blocked the sustained induction of CYP24 expression by 1,25(OH)(2)D(3) and EB 1089, increased the potency of 1,25(OH)(2)D(3) and EB 1089, and inhibited breast tumor cell proliferation and invasion.

Life-threatening bradyarrhythmia after massive azithromycin overdose.

9-month-old infant was inadvertently administered azithromycin 50 mg/kg, taken from floor stock, instead of the prescribed ceftriaxone. Shortly thereafter, she became unresponsive and pulseless. The initial heart rhythm observed when cardiopulmonary resuscitation was started was a widecomplex bradycardia, with a prolonged rate-corrected QT interval and complete heart block. The baby was resuscitated with epinephrine and atropine, but she suffered severe anoxic encephalopathy. Torsade de pointes and QT-interval prolongation have been reported after administration of macrolide antibiotics, including azithromycin, both intravenously and orally. This has occurred especially in the context of coadministered drugs that inhibit the cytochrome P450 (CYP) 3A4 isoenzyme, such as ketoconazole and astemizole. However, bradycardia with complete heart block has not, to our knowledge, been reported specifically with intravenous administration of azithromycin alone, either with therapeutic doses or overdose. Clinicians should be alerted about the potential of azithromycin to cause life-threatening bradycardia, and pharmacy systems should be implemented to ensure special care in the safe administration of this drug, especially when dispensed from a point-of-care source.

The use of high-dose epinephrine for patients with out-of-hospital cardiopulmonary arrest refractory to prehospital interventions.

OBJECTIVE: To determine if high-dose epinephrine (HDE) used during out-of-hospital cardiopulmonary arrest refractory to prehospital interventions improves return of spontaneous circulation, 24-hour survival, discharge survival, and neurological outcomes. METHODS: A multicenter randomized controlled trial was conducted between May 1991 and October 1996 to compare the effectiveness of HDE versus standard-dose epinephrine (SDE) in patients having out-of-hospital cardiopulmonary arrest refractory to prehospital resuscitation efforts. Cardiopulmonary arrest was classified as "medical" or "traumatic." Two hundred thirty patients were enrolled in 7 pediatric emergency departments. Ages ranged from newborn to 22 years. Seventeen patients met exclusion criteria. Patients were assigned to receive HDE (0.1 mg/kg for the initial dose and 0.2 mg/kg for subsequent doses) or SDE (0.01 mg/kg). The main end points evaluated were return of spontaneous circulation, 24-hour survival, discharge survival, and neurological outcome. RESULTS: One hundred twenty-seven patients received HDE (32 trauma patients), and 86 patients received SDE (27 trauma patients). Among medical patients, 24 (25%) of 95 experienced return of spontaneous circulation in the HDE group as compared with 9 (15%) of 59 in the SDE group (P = 0.14, chi2 = 2.17, relative risk = 1.66 [0.83-3.31]). Sixteen (17%) of 95 HDE patients and 5 (8%) of 59 SDE patients survived at least 24 hours (P = 0.14, chi2 = 2.16, relative risk = 1.99 [0.77-5.14]). Nine survivors to discharge received HDE, and 2 received SDE (P = 0.21, Fisher exact test, relative risk = 2.75 [0.61-12.28]). There were no long-term survivors among the trauma patients. Eight of 11 long-term survivors had severe neurological outcomes defined by the Glasgow Outcome Scale (2/2 SDE, 6/9 HDE; P = 0.51, Fisher exact test). CONCLUSION: HDE does not improve or diminish return of spontaneous circulation, 24-hour survival, long-term survival, or neurological outcome compared with SDE in out-of-hospital cardiopulmonary arrest.

Passenger seating position and the risk of passenger death or injury in traffic crashes.

OBJECTIVE: To estimate the association of passenger seat position with the risk of death and serious injury for passengers in traffic crashes. METHODS: Using 1993-2000 data from the National Highway Traffic Safety Administration's Crashworthiness Data System (CDS), the risk ratio for death and serious injury was estimated for rear seat passengers compared with front seat passengers in motor vehicle crashes. RESULTS: The adjusted risk ratio for death of passengers in the rear seat in a crash was 0.61 (95% confidence interval (CI) 0.46-0.81). Rear seat passenger position was also associated with a decrease in the risk of death and serious injury compared with the front seat passenger position: risk ratio=0.67 (95% CI 0.57-0.78). CONCLUSION: We estimated that the rear seat passenger position may reduce the risk of death in a motor vehicle crash by about 39% and reduce the risk of death or serious injury in a crash by 33%, compared with the front seat passenger position. If the associations that we report are causal, sitting in the rear seat, compared with the front seat, may prevent about 4 in 10 passenger deaths, or 3 in 10 passenger deaths and injuries, that might otherwise occur.