Abstract Pregnancy is a unique period regarding immune cell regulation. Within the placenta, maternal immune cells play a central role in immune surveillance and tissue remodeling. However, regulatory mechanisms of systemic immunity during pregnancy are less clear. Here, we show that neutrophil function is altered in pregnant mice (E13.5), indicated by increased slow rolling velocity and reduced adhesion. Mechanistically, PreImplantation factor (PIF), a 15 amino acid peptide which is produced by human and murine trophoblast cells of the placenta, is continuously secreted into the maternal circulation and plays a key role in modulating neutrophil function via blocking the voltage-gated potassium channel K V 1.3. This resulted in impaired intracellular Ca 2+ signaling and subsequently disturbance of neutrophil post-arrest modifications and a higher susceptibility to physiological shear forces in vivo and in vitro . Furthermore, PIF-mediated K V 1.3 blockade impaired E-selectin-mediated release of S100A8/A9 and phagocytosis. Taken together, we have identified PIF as an important modulator of neutrophil function during pregnancy suggesting a critical role in regulating innate immune responses throughout gestation.

Diabetic wounds have limited effective therapies to restore tissue repair and resolve excessive inflammation. This study aimed to identify mechanisms of diabetic wound healing defects and test a therapeutic intervention using diabetic mouse and pig models. Here, we show that Smad7 transgene expression in mouse epidermis promotes wound healing in diabetic mice. To restrict the therapeutic effects of Smad7 on wounds, we develop a Smad7-based biologic (Tat-PYC-Smad7) that penetrates cells of the wound. Topical Tat-PYC-Smad7 treatment to diabetic pig and mouse wounds accelerates healing. Tat-PYC-Smad7-treated wounds exhibit reduced TGFβ/NFκB signaling, faster re-epithelialization, and better extracellular matrix remodeling compared to vehicle controls. Tat-PYC-Smad7 also attenuates neutrophil extracellular trap (NET) formation, potentially acting through reductions in MPO enzymatic activity and MPO nuclear entry, consequently reducing chromatin decondensation and the release of NET components. Our study reveals that keratinocytes and neutrophils are the two major cell types targeted by Tat-PYC-Smad7 to promote diabetic wound healing, providing insight into mechanisms of diabetic wound healing defects targetable by Smad7-based therapy.

While T cells play a prominent role, polymorphonuclear neutrophils (PMN) are also significant players in the pathogenesis of psoriasis. This review details the mechanobiology of PMN in the amplification of skin inflammation, a process often under-scrutinized compared to T cell pathways. PMN surveillance of skin microcirculation involves selectin-mediated rolling that transitions to stable β2-integrin-mediated arrest. Upon tissue recruitment, PMN trigger the NLRP3 inflammasome and NETosis, releasing neutrophil extracellular traps, proinflammatory cytokines including IL-1β and IL-18, and damage-associated molecular patterns. These mediators promote keratinocyte proliferation and recruit additional waves of PMN that contribute to a positive feedback loop that sustains skin inflammation and hyperproliferation of keratinocytes. Consequently, assays measuring PMN activation provide a sensitive biomarker for the progression of psoriatic disease. Furthermore, therapeutically targeting upstream mechanosignaling pathways presents a novel therapeutic avenue to move beyond conventional strategies that block downstream cytokines critical for immunocompetence.

BackgroundDespite the increasing use of non-invasive imaging, DSA remains the gold standard for cerebrovascular imaging. However, trends in DSA utilization are poorly understood. The goal of this study was to describe DSA utilization in a large claims database in the US over a 13 year period.MethodsThis retrospective cohort study assessed a nationwide database of privately insured individuals from 2005 to 2018 for patients undergoing cranial CT angiography (CTA), MR angiography (MRA), and DSA. We assessed trends in the overall use of and indications for each modality. For DSA, we examined the types of performing proceduralists.ResultsAmong patients undergoing DSA in 2018, median age was 52 years, and 60% were women. MRA and DSA use decreased, from 289 to 275 claims, and from 38 to 29 claims per 100 000 enrollees, respectively, while CTA use increased from 31 to 286 claims per 100 000 enrollees. These trends differed by geographic region and indication. Nearly half of DSA procedures but <25% of non-invasive imaging were inpatient studies. DSA performed by neurosurgeons increased from 0.5 to 4.1 while those performed by radiologists decreased from 7.2 to 4.0 studies per 100 000 enrollees.ConclusionsDSA use decreased slightly while CTA use increased by ninefold. The reasons for this change are likely complex and may reflect more aggressive imaging for stroke, increased detection of incidental findings, and increased quality of non-invasive imaging. Over time, the proportion of DSA procedures performed by neurosurgeons overtook that performed by radiologists.

Hypertriglyceridemia (HTG), particularly in combined hyperlipidemia, increases risk for atherosclerotic cardiovascular disease, but the underlying mechanisms remain incompletely understood. We sought to determine contributions of circulating monocytes to atherosclerosis associated with HTG in combined hyperlipidemia, created by transgenic expression of human apoCIII in Ldlr-/- mice (Ldlr-/-ApoCIIItg) fed Western high-fat diet (WD). Tissue culture with THP-1 and primary human monocytes was used to examine effects of triglyceride (TG)-rich lipoproteins on monocytes. Ldlr-/-ApoCIIItg mice were also treated with apoCIII antisense oligonucleotide (ASO) and examined for foamy monocytes and atherosclerosis. Compared to Ldlr-/- mice, Ldlr-/-ApoCIIItg mice fed WD had early and persistent increases in lipid accumulation within monocytes and enhanced atherosclerosis. Ldlr-/-ApoCIIItg mice versus Ldlr-/- mice had higher levels of CD11c, CD36, and cytokines in foamy monocytes, with increases in foamy monocyte adhesion to vascular cell adhesion molecule-1 and oxidized LDL uptake. Monocytes took up TG-rich lipoprotein in vivo and in vitro and changed phenotypes. Foamy monocytes infiltrated into atherosclerotic lesions, and specific and sustained depletion of CD11c+ (foamy) monocytes profoundly reduced atherosclerosis in Ldlr-/-ApoCIIItg mice on WD. Treatment with apoCIII ASO lowered plasma TG and cholesterol levels, improved foamy monocyte phenotypes, and reduced atherosclerosis in Ldlr-/-ApoCIIItg mice. In conclusion, HTG in combined hyperlipidemia accelerates atherosclerosis, in part, by increasing foamy monocyte formation and infiltration into atherosclerotic plaques. Treatment with apoCIII ASO is a potential new therapy for improving monocyte phenotypes and reducing atherosclerosis in combined hyperlipidemia.

Mitochondrial dysfunction, which can be caused by metabolic stressors such as oxidized low-density lipoprotein (oxLDL), sensitizes the endothelium to pathological changes. The transcription factor interferon regulatory factor 1 (IRF-1) is a master regulator of inflammation, previously shown to promote oxLDL-induced inflammatory pyroptosis in human aortic endothelial cells (HAEC). However, a presumed role for IRF-1 in regulating the intrinsic apoptotic pathway in response to metabolic stress has not been demonstrated. Here targeted deletion of IRF-1 by siRNA in HAEC aggravated oxLDL-induced, mitochondria-mediated intrinsic apoptosis, as evidenced by increased Caspase-3 and Caspase-9 activation, and chromosomal DNA breakage. The increased apoptosis was concomitant with accumulation of mitochondrial ROS, decrease in intracellular ATP production and respiratory oxygen consumption, and abnormal mitochondrial structure. RNA profiling of endothelial cells isolated from wild type and Irf1 knockout mice, followed by quantitative PCR, luciferase activity assay and chromatin immunoprecipitation (ChIP), revealed that IRF-1 directly regulated the expression of transmembrane protein 70 (TMEM70), an ancillary factor required for the assembly of ATP synthase and conversion of an electrochemical gradient to ATP synthesis. Mirroring the effect of IRF1 knockdown, depletion of TMEM70 in HAEC resulted in impaired mitochondrial function and enhanced cell apoptosis. In contrast, overexpression of TMEM70 rescued ATP biosynthesis and suppressed apoptosis in oxLDL-treated, IRF-1-deficient HAEC. These results reveal a novel homeostatic role for IRF-1 in the regulation of mitochondrial function and associated stress-induced apoptosis.

Introduction: Improved imaging modalities have led to an increased detection of intracranial aneurysms, many of which are small. While studies have shown that many ruptured intracranial aneurysms are small (≤7 mm), the natural history of tiny (≤3 mm) aneurysms, particularly in certain locations such as the middle cerebral artery (MCA) is thought to be relatively benign with a reported rupture rate of less than 0.5% per year. The objective of this study is to evaluate the safety and efficacy of treatment of tiny unruptured MCA aneurysms. Methods: The NVQI-QOD registry was queried for patients with tiny unruptured MCA aneurysms who underwent either microsurgical or endovascular repair. Tiny size was defined as an aneurysm with a maximum dimension of ≤3 mm. Demographics, aneurysm characteristics and treatment safety were queried. Safety data included intra-operative and post-operative complications. Outcomes included modified Rankin Score (mRS) at discharge and last follow up as well as aneurysm occlusion status at discharge. Results: Of 670 treated, unruptured MCA aneurysms, 43 were tiny (6.4%). The mean aneurysm width was 1.9 mm with a mean patient age of 56.3 years. The median pre-operative mRS was 0 (range 0-4). The majority of patients underwent microsurgery (27/43). The overall intra-operative complication rate was 7% (3/43) with an intra-operative rupture rate of 4.7% (2/43). The post-operative complication rate was 9.3% (4/43). New intracerebral hemorrhage occurred in 7% of patients (3/43) and unplanned return to OR occurred in 14.8% of patients who underwent microsurgery (4/27). There were no mortalities. 16.3% (7/43) of patients were discharged to inpatient rehabilitation or a skilled nursing facility. At discharge, 37 (88.1%) patients had complete aneurysm occlusion. In the subgroup of patients with recorded follow up data, only 40% (10/25) had a mRS of 0 at discharge and 40% (6/15) had an mRS of 0 at last follow up (median follow up: 165 days). Conclusions: Our analysis showed that treatment of tiny unruptured MCA aneurysms is associated with a high rate of complications. We suggest that many tiny, unruptured MCA aneurysms should be observed given that the morbidity associated with treatment is likely significantly higher than the risk of rupture.

Psoriasis is one of the most common inflammatory skin diseases in the world and affects 2–3% of the United States population. Decades of research have resulted in advancing our understanding of psoriasis pathogenesis and in the development of more than 10 Food and Drug Administration (FDA)–approved biologic and small-molecule agents that are relatively safe and can be used to treat psoriasis and psoriatic arthritis with variable levels of expected efficacy. Despite the high success rate in treating psoriasis, its etiology remains unknown beyond the involvement of predisposing genes and the interplay with the cutaneous microenvironment.

Neutrophils are the first line of defense of the innate immune system. In response to methicillin-resistant Staphylococcus aureus infection in the skin, hematopoietic stem, and progenitor cells (HSPCs) traffic to wounds and undergo extramedullary granulopoiesis, producing neutrophils necessary to resolve the infection. This prompted the engineering of a gelatin methacrylate (GelMA) hydrogel that encapsulates HSPCs within a matrix amenable to subcutaneous delivery. The authors study the influence of hydrogel mechanical properties to produce an artificial niche for granulocyte-monocyte progenitors (GMPs) to efficiently expand into functional neutrophils that can populate infected tissue. Lin-cKIT+ HSPCs, harvested from fluorescent neutrophil reporter mice, are encapsulated in GelMA hydrogels of varying polymer concentration and UV-crosslinked to produce HSPC-laden gels of specific stiffness and mesh sizes. Softer 5% GelMA gels yield the most viable progenitors and effective cell-matrix interactions. Compared to suspension culture, 5% GelMA results in a twofold expansion of mature neutrophils that retain antimicrobial functions including degranulation, phagocytosis, and ROS production. When implanted dermally in C57BL/6J mice, luciferase-expressing neutrophils expanded in GelMA hydrogels are visualized at the site of implantation for over 5 days. They demonstrate the potential of GelMA hydrogels for delivering HSPCs directly to the site of skin infection to promote local granulopoiesis.

Psoriasis is an inflammatory disease that is initiated by pathogenic T cells within skin lesions that correlates with hyperproliferation of keratinocytes and the release of cytokines and damage-associated molecular pattern molecules into the circulation (Wang and Jin, 2020). Exposure to damage-associated molecular patterns and low levels of cytokines and chemokines shift neutrophils from a quiescent to a primed state characterized by increased sensitivity to subsequent stimulation that induces amplified adhesive and effector function at sites of tissue inflammation (Miralda et al, 2017).

Acute ischemic stroke occurs when a blood clot occludes a cerebral artery. Mechanical interventions, primarily stent retrievers and aspiration thrombectomy, are used currently for removing the occluding clot and restoring blood flow. Aspiration involves using a long catheter to traverse the cerebral vasculature to reach the blood clot, followed by application of suction through the catheter bore. Aspiration is also used in conjunction with other techniques such as stent retrievers and balloon guide catheters. Despite the wide use of aspiration, our physical understanding of the process and the causes of the failure of aspiration to retrieve cerebral clots in certain scenarios is not well understood. Experimental and computational studies can help develop the capability to provide deeper insights into the procedure and enable development of new devices and more effective treatment methods. We recapitulate the aspiration-based thrombectomy techniques in clinical practice and provide a perspective of existing engineering methods for aspiration. We articulate the current knowledge gap in the understanding of aspiration and highlight possible directions for future engineering studies to bridge this gap, help clinical translation of engineering studies, and develop new patient-specific stroke therapy.

Introduction: Based largely on the inclusion criteria of clinical trials, the degree of cervical carotid artery stenosis is often used as an indication for stent placement in the setting of carotid atherosclerotic disease. However, the rigor and consistency with which such stenosis is measured outside of clinical trials is unclear. We compared the percent stenosis as measured by real world physician operators to that measured by independent expert reviewers. Hypothesis: We hypothesized that the documented degree of stenosis, termed operator-reported stenosis (ORS), from real world facilities performing carotid stent placement would be larger than the reviewer-measured stenosis (RMS) as assessed by clinicians experienced in treating carotid artery disease. Methods: Images were selected from patient cases used for carotid stenting facility accreditation. Data collected included demographics, National Institutes of Health Stroke Scale, modified Rankin Score, and the documented degree of stenosis (ORS). The ORS was compared to the RMS, derived from a panel of expert clinicians. Results: A total of 68 angiograms were reviewed from 39 symptomatic and 29 asymptomatic patients. The RMS values demonstrated excellent agreement with an intra-class correlation of 0.80. The median ORS was 90.0% (IQR 80.0, 90.0) versus a median RMS of 61.1% (IQR 49.8, 73.6), with a median difference of 21.8% (IQR 13.7, 34.4), p < 0.001. This discrepancy persisted within several subpopulations and was larger among asymptomatic patients and those treated at facilities granted delayed accreditation. Based on RMS values, 72% of symptomatic patients and only 10% of asymptomatic patients would meet the Centers for Medicare and Medicaid Services criteria for carotid stent placement. Conclusions: Real world operators tend to overestimate cervical carotid artery stenosis compared to external expert reviewers. Since decisions regarding carotid revascularization are often based at least partially on percent stenosis, such measuring discrepancies inevitably lead to a higher volume of procedures, which may in turn represent a degree of procedural over utilization.

In patients with hypertriglyceridemia, a short-term low-saturated fat vs high-saturated fat diet induced lower plasma lipids and improved monocyte phenotypes. These findings highlight the role of diet fat content and composition for monocyte phenotypes and possibly cardiovascular disease risk in these patients. (Effects of Dietary Interventions on Monocytes in Metabolic Syndrome; NCT03591588).

Diabetes mellitus is a chronic disease characterized by metabolic dysregulation which is frequently associated with diabetic foot ulcers that result from a severely compromised innate immune system. The high levels of blood glucose characteristic of diabetes cause an increase in circulating inflammatory mediators, which accelerate cellular senescence and dampen antimicrobial activity within dermal tissue. In diabetic wounds, bacteria and fungi proliferate in a protective biofilm forming a structure that a compromised host defense system cannot easily penetrate, often resulting in chronic infections that require antimicrobial intervention to promote the healing process. The designed host defense peptide (dHDP) RP557 is a synthesized peptide whose sequence has been derived from naturally occurring antimicrobial peptides (AMPs) that provide the first line of defense against invading pathogens. AMPs possess an amphipathic α-helix or β-sheet structure and a net positive charge that enables them to incorporate into pathogen membranes and perturb the barrier function of Gram-positive and Gram-negative bacteria along with fungi. The capacity of skin to resist infections is largely dependent upon the activity of endogenous AMPs that provided the basis for the design and testing of RP557 for the resolution of wound infections. In the current study, the topical application of RP557 stopped bacterial growth in the biofilm of methicillin-resistant Staphylococcus aureus (MRSA) USA300 infected wounds on the flanks of clinically relevant diabetic TALLYHO mice. Topical application of RP557 reduced bacterial load and accelerated wound closure, while wound size in control diabetic mice continued to expand. These studies demonstrate that RP557 reduces or eliminates an infection in its biofilm and restores wound-healing capacity.

Acute ischemic stroke (AIS) is a leading cause of mortality that occurs when an embolus becomes lodged in the cerebral vasculature and obstructs blood flow in the brain. The severity of AIS is determined by the location and how extensively emboli become lodged, which are dictated in large part by the cerebral flow and the dynamics of embolus migration which are difficult to measure in vivo in AIS patients. Computational fluid dynamics (CFD) can be used to predict the patient-specific hemodynamics and embolus migration and lodging in the cerebral vasculature to better understand the underlying mechanics of AIS. To be relied upon, however, the computational simulations must be verified and validated. In this study, a realistic in vitro experimental model and a corresponding computational model of the cerebral vasculature are established that can be used to investigate flow and embolus migration and lodging in the brain. First, the in vitro anatomical model is described, including how the flow distribution in the model is tuned to match physiological measurements from the literature. Measurements of pressure and flow rate for both normal and stroke conditions were acquired and corresponding CFD simulations were performed and compared with the experiments to validate the flow predictions. Overall, the CFD simulations were in relatively close agreement with the experiments, to within ±7% of the mean experimental data with many of the CFD predictions within the uncertainty of the experimental measurement. This work provides an in vitro benchmark data set for flow in a realistic cerebrovascular model and is a first step towards validating a computational model of AIS.

INTRODUCTION: Evidence suggests routine post-operative intensive care unit (ICU) admission in high-risk neurosurgical procedures, including endovascular treatment of unruptured intracranial aneurysms (UIA), may be unnecessary, though current practice patterns are undescribed. We sought to evaluate trends in ICU utilization in patients undergoing elective endovascular repair of UIA in the United States. METHODS: This is a retrospective cohort study utilizing commercial claims from a nationwide longitudinal database of multiple payors in the U.S. (MarketScan) to evaluate ICU use in patients undergoing elective, endovascular repair of UIA between 2005 and 2019. Our initial cohort was defined using diagnosis codes and CPT procedural codes. Patients with ruptured aneurysms were excluded, and the remaining unruptured patients were separated by ICU revenue codes to identify those who were likely admitted to the ICU post-operatively. A combination of diagnosis codes and procedural codes were utilized to evaluate demographics, pre-operative comorbidities, post-procedural complications, and discharge status. Cost analysis was also performed. RESULTS: Of 6218 patients who underwent elective endovascular treatment of UIA, 78.6% (4890) of patients were placed in the ICU post-operatively, and this percentage remained stable over the study period. No differences in age, sex, comorbidity scores, or smoking history were found between patients admitted to the ICU versus those admitted to the floor. ICU utilization was more common in urban locations (p < 0.001). The average total payment was higher in patients admitted to the ICU post-operatively ($46,429 versus $40,552, p < 0.0001). CONCLUSIONS: Almost 80% of patients undergoing elective endovascular repair of UIA are admitted to the ICU postoperatively, despite multiple studies suggesting this practice is unnecessary. Costs are significantly higher in patients utilizing the ICU. Reducing routine ICU use in this subgroup of patients may reduce costs and resource utilization in a safe manner.