The Responsiveness of the Patient-Reported Outcomes Measurement Information System Upper Extremity and Physical Function in Patients With Cubital Tunnel Syndrome.

PURPOSE: The Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity (UE) and PROMIS Physical Function (PF) are increasingly referenced patient-reported outcomes. To interpret treatment effects with these patient-reported outcomes, investigators must understand magnitudes of change that represent clinically relevant improvement. This study assessed the responsiveness of PROMIS UE and PF in patients with cubital tunnel syndrome. METHODS: A retrospective analysis of PROMIS UE and PROMIS PF computer adaptive test scores was performed for patients treated nonoperatively for cubital tunnel syndrome over 3 years at a tertiary institution. The Patient-Reported Outcomes Measurement Information System UE and PROMIS PF outcome scores were collected at initial and return clinic visits. At follow-up appointments, patients completed clinical anchor questions evaluating their degree of interval clinical improvement. Anchor questions allowed categorization of patients into groups that had experienced "no change," "minimal change," and "much change." Minimal clinically important difference (MCID) values were calculated for the PROMIS assessments with anchor-based and distribution-based methods. RESULTS: A total of 304 patients with PROMIS PF scores and 111 with PROMIS UE scores were analyzed. The MCID for the PROMIS UE was 3.1 (95% confidence interval, 1.4-4.8) using the anchor-based method and 3.7 (95% confidence interval, 2.9-4.4) using the distribution-based method. These point estimates exceeded the minimal detectable change of 2.3. The MCID for the PROMIS PF was unable to be determined in this patient sample because patients reporting mild change did not have score changes exceeding measurement error. CONCLUSIONS: The PROMIS UE v2.0 computer adaptive test detected minimal change in patients managed nonoperatively for cubital tunnel syndrome with an estimated MCID range of 3.1-3.7. While PROMIS PF has demonstrated acceptable performance in patients with a variety of upper extremity conditions, for cubital tunnel syndrome, it was less able to detect subtle change. PROMIS UE appears more responsive to subtle changes in cubital tunnel syndrome symptoms. CLINICAL RELEVANCE: Patient-reported outcomes may have varied responsiveness depending on the condition studied.

Functional Outcomes and Health-Related Quality of Life of Adults With Congenital Below-Elbow Amputation in North America.

PURPOSE: Congenital below-elbow amputation (BEA) is a common upper-extremity anomaly and generally encompasses 2 diagnoses, symbrachydactyly and transverse deficiency. Little is known about the physical, mental, and social well-being of adults with congenital BEA. A deeper understanding of longitudinal outcomes within this population may help guide family conversations and counseling for patients with congenital BEA. METHODS: The Shriners Hospitals for Children Health Outcomes Network was queried to identify all patients currently >18 years of age who had been seen as a child between 1975 and 2019 for congenital BEA at 1 of 20 Shriners Hospitals across North America. A unique health survey examining physical functioning, mental health, social outcomes, and health-related quality of life was constructed and sent by mail or in electronic form to eligible patients. RESULTS: A total of 64 questionnaires were completed. Patients ranged between 18 and 34 years of age, and 70% were female. Nearly two-thirds of patients (64%) reported that a prosthesis was not required and only 14% reported daily prosthetic use. Although respondents reported below-average Patient-Reported Outcomes Measurement Information System (PROMIS) upper-extremity scores, there were no differences in Short-Form 12 or Quick Disabilities of the Arm, Shoulder, and Hand scores relative to the US general population. Study participants had lower PROMIS Pain Intensity and higher PROMIS satisfaction with social roles and activities scores than the US general population, translating to clinically meaningful differences. CONCLUSIONS: Although adults with congenital BEA report lower upper-extremity functional scores than the general population, they report no clear differences from normative values in self-efficacy, psychosocial well-being, health-related quality of life, or global life satisfaction. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

An Analysis of Associated Conditions and the Relationship Between the Severity of Hand Manifestations With That of the Forearm in Ulnar Longitudinal Deficiency.

PURPOSE: A deeper investigation of medical and musculoskeletal conditions in patients with ulnar longitudinal deficiency (ULD) is needed. The association between the severity of the manifestations of ULD in the hands and forearms has not been firmly established. The purpose of this study was to describe the medical and musculoskeletal conditions associated with ULD and examine the relationship between hand and forearm anomalies. METHODS: The Congenital Upper Limb Differences registry was queried for all patients with a diagnosis of ULD, as defined by the Oberg-Manske-Tonkin classification system, between 2014 and 2020. The patients' demographic information, medical and musculoskeletal comorbidities, radiographs, and clinical images were reviewed. The participants were classified using the Bayne, Cole and Manske, and Ogino classification systems. RESULTS: Of 2,821 patients from the Congenital Upper Limb Differences registry, 75 patients (2.7%) with ULD (14 bilateral), with 89 affected extremities, were included. Hand anomalies were present in 93% of the patients. Approximately 19% of the patients had an associated medical comorbidity, and 20% of the patients had an associated musculoskeletal condition. Cardiac anomalies were present in 8.0% of the patients, and 12% of the patients had a lower extremity abnormality. Radial head dislocation was observed in 13 of 18 patients with Bayne type II or III ULD compared with 8 of 43 patients with other types of unilateral ULD. There was a significant positive association among the Bayne and Ogino, Bayne and Cole/Manske, and Ogino and Cole/Manske classification systems in patients with unilateral ULD. CONCLUSIONS: Associated medical and musculoskeletal conditions are common in patients with ULD, of which cardiac and lower extremity abnormalities are most frequently observed. There is a significant positive association between the severity of forearm anomalies and that of hand anomalies in patients with unilateral ULD. All patients with ULD should undergo a thorough cardiac evaluation by their pediatrician or a pediatric cardiologist. TYPE OF STUDY/LEVEL OF EVIDENCE: Symptom prevalence study III.

What Is the Financial Impact of Orthopaedic Sequelae of Intravenous Drug Use on Urban Tertiary-care Centers?

BACKGROUND: Orthopaedic sequelae such as skin and soft-tissue abscesses are frequent complications of intravenous drug use (IVDU) and comprise many of the most common indications for emergency room visits and hospitalizations within this population. Urban tertiary-care and safety-net hospitals frequently operate in challenging economic healthcare environments and are disproportionately tasked with providing care to this largely underinsured patient demographic. Although many public health initiatives have been instituted in recent years to understand the health impacts of IVDU and the spreading opioid epidemic, few efforts have been made to investigate its economic impact on healthcare systems. The inpatient treatment of orthopaedic sequelae of IVDU is a high-cost healthcare element that is critically important to understand within the current national context of inflationary healthcare costs. QUESTIONS/PURPOSES: (1) What were the total healthcare costs incurred and total hospital reimbursements received in the treatment of extraspinal orthopaedic sequelae of IVDU? (2) What were the total healthcare costs incurred and total hospital reimbursements received in the treatment of spinal orthopaedic sequelae of IVDU? (3) How did patient insurance status effect the economic burden of orthopaedic sequelae of IVDU? METHODS: An internal departmental record of all successive patients requiring inpatient treatment of orthopaedic sequelae of IVDU was initiated at Boston Medical Center (Boston, MA, USA) in 2012 and MetroHealth Medical Center (Cleveland, OH, USA) in 2015. A total of 412 patient admissions between 2012 to 2017 to these two safety-net hospitals (n = 236 and n = 176, respectively) for orthopaedic complications of IVDU were included in the study. These sequelae included cellulitis, cutaneous abscess, bursitis, myositis, tenosynovitis, septic arthritis, osteomyelitis, and epidural abscess. Patients were included if they were older than 18 years of age, presented to the emergency department for management of a musculoskeletal infection secondary to IVDU, and required inpatient orthopaedic treatment during their admission. Exclusion criteria included all patients presenting with a musculoskeletal infection not directly secondary to active IVDU. Patients presenting with an epidural abscess (Boston Medical Center, n = 36) were evaluated separately to explore potential differences in costs within this subgroup. A robust retrospective financial analysis was performed using internal financial databases at each institution which directly enumerated all true hospital costs associated with each patient admission, independent of billed hospital charges. All direct, indirect, variable, and fixed hospital costs were individually summed for each hospitalization, constituting a true "bottom-up" micro-costing approach. Labor-based costs were calculated through use of time-based costing; for instance, the cost of nursing labor care associated with a patient admission was determined through ascription of the median hospital cost of a registered nurse within that department (that is, compensation for salary plus benefits) to the total length of nursing time needed by that patient during their hospitalization. Primary reimbursements reflected the true monetary value received by the study institutions from insurers and were determined through the total adjusted payment for each inpatient admission. All professional fees were excluded. A secondary analysis was performed to assess the effect of patient insurance status on hospital costs and reimbursements for each patient admission. RESULTS: The mean healthcare cost incurred for the treatment of extraspinal orthopaedic sequelae of IVDU was USD 9524 ± USD 1430 per patient admission. The mean hospital reimbursement provided for the treatment of these extraspinal sequelae was USD 7678 ± USD 1248 per patient admission. This resulted in a mean financial loss of USD 1846 ± USD 1342 per patient admission. The mean healthcare cost incurred at Boston Medical Center for the treatment of epidural abscesses secondary to IVDU was USD 44,357 ± USD 7384 per patient. Hospital reimbursements within this subgroup were highly dependent upon insurance status. The median (range) reimbursement provided for patients possessing a unique hospital-based nonprofit health plan (n = 4) was USD 103,016 (USD 9022 to USD 320,123), corresponding to a median financial gain of USD 24,904 (USD 2289 to USD 83,079). However, the mean reimbursement for all other patients presenting with epidural abscesses (n = 32) was USD 30,429 ± USD 5278, corresponding to a mean financial loss of USD 5768 ± USD 4861. A secondary analysis demonstrated that treatment of extraspinal orthopaedic sequelae of IVDU for patients possessing Medicaid insurance (n = 309) resulted in a financial loss of USD 2813 ± USD 1593 per patient admission. Conversely, treatment of extraspinal orthopaedic sequelae for patients possessing non-Medicaid insurance (n = 67) generated a mean financial gain of USD 2615 ± USD 1341 per patient admission. CONCLUSIONS: Even when excluding all professional fees, the inpatient treatment of orthopaedic sequelae of IVDU resulted in substantial financial losses driven primarily by high proportions of under- and uninsured people within this patient population. These financial losses may be unsustainable for medical centers operating in challenging economic healthcare landscapes. The development of novel initiatives and support of existing programs aimed at mitigating the health-related and economic impact of IVDU must remain a principal priority of healthcare providers and policymakers in coming years. Advocacy for the expansion of Medicaid accountable care organizations and national syringe service programs (SSPs), and the development of specialized outpatient wound and abscess clinics at healthcare centers may help to substantially alleviate the economic burden of the orthopaedic sequelae of IVDU. LEVEL OF EVIDENCE: Level, IV, economic and decision analyses.

Deimination of linker histones links neutrophil extracellular trap release with autoantibodies in systemic autoimmunity.

Autoantibodies to nuclear antigens arise in human autoimmune diseases, but a unifying pathogenetic mechanism remains elusive. Recently we reported that exposure of neutrophils to inflammatory conditions induces the citrullination of core histones by peptidylarginine deiminase 4 (PAD4) and that patients with autoimmune disorders produce autoantibodies that recognize such citrullinated histones. Here we identify histone H1 as an additional substrate of PAD4, localize H1 within neutrophil extracellular traps, and detect autoantibodies to citrullinated H1 in 6% of sera from patients with systemic lupus erythematosus and Sjögren's syndrome. No preference for deiminated H1 was observed in healthy control sera and sera from patients with scleroderma or rheumatoid arthritis. We map binding to the winged helix of H1 and determine that citrulline 53 represents a key determinant of the autoantibody epitope. In addition, we quantitate RNA for H1 histone subtypes in mature human neutrophils and identify citrulline residues by liquid chromatography and tandem mass spectrometry. Our results indicate that deimination of linker histones generates new autoantibody epitopes with enhanced potential for stimulating autoreactive human B cells.-Dwivedi, N., Neeli, I., Schall, N., Wan, H., Desiderio, D. M., Csernok, E., Thompson, P. R., Dali, H., Briand, J.-P., Muller, S., Radic, M. Deimination of linker histones links neutrophil extracellular trap release with autoantibodies in systemic autoimmunity.

Poloxamer surfactant preserves cell viability during photoacoustic delivery of molecules into cells.

Efficient intracellular delivery of molecules is needed to modulate cellular behavior for laboratory and medical applications, but is often limited by trade-offs between achieving high intracellular delivery and maintaining high cell viability. Here, we studied photoacoustic delivery of molecules into cells by exposing DU145 human prostate carcinoma cells to nanosecond laser pulses in the presence of carbon black nanoparticles. Under strong laser exposure conditions, less than 30% of cells were viable and exhibited uptake. Addition of poloxamer surfactant at those laser exposure conditions increased cell viability to almost 90%, with intracellular uptake in >80% of cells. This remarkable increase in efficiency of intracellular delivery and cell viability may be attributed to enhanced cell membrane resealing by poloxamer surfactant after photoacoustic delivery. While F-68 poloxamer was effective, the larger, more-hydrophobic F-127 poloxamer provided the best results. There was no significant protective effect from addition of Ca(2+) , BAPTA-AM, ATP, fetal bovine serum or glycine betaine, which were expected to promote active cell membrane repair mechanisms and other active intracellular protective processes. We conclude that poloxamer surfactant preserves cell viability during photoacoustic delivery of molecules into cells, thereby enabling highly efficient intracellular delivery.

Citrullination of autoantigens implicates NETosis in the induction of autoimmunity.

Tolerance blocks the expression of autoantibodies, whereas autoimmunity promotes it. How tolerance breaks and autoantibody production begins thus are crucial questions for understanding and treatment of autoimmune diseases. Evidence implicates cell death and autoantigen modifications in the initiation of autoimmune reactions. One form of neutrophil cell death called NETosis deserves attention because it requires the post-translational modification of histones and results in the extracellular release of chromatin. NETosis received its name from NET, the acronym given to Neutrophil Extracellular Trap. The extracellular chromatin incorporates histones in which arginines have been converted to citrullines by peptidylarginine deiminase IV (PAD4). The deiminated chromatin may function to capture or 'trap' bacterial pathogens, thus generating an extracellular complex of deiminated histones and bacterial cell adjuvants. The complex of bacterial antigens and deiminated chromatin may be internalised by host phagocytes during acute inflammatory conditions, as arise during bacterial infections or chronic autoinflammatory disorders. The uptake and processing of deiminated chromatin together with bacterial adjuvants by phagocytes may induce the presentation of modified histone epitopes and co-stimulation, thus yielding a powerful stimulus to break tolerance. Autoantibodies to deiminated histones are prevalent in Felty's syndrome patients and are present in systemic lupus erythematosus (SLE) and patients with rheumatoid arthritis (RA). These observations clearly implicate histone deimination as an epigenetic mark that can act as an autoantibody stimulant.

Felty's syndrome autoantibodies bind to deiminated histones and neutrophil extracellular chromatin traps.

OBJECTIVE: To test the hypothesis that autoantigen modifications by peptidylarginine deiminase type 4 (PAD-4) increase immunoreactivity. METHODS: We assembled sera from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Felty's syndrome (FS), and antineutrophil cytoplasmic antibody-associated vasculitides (AAVs), as well as sera from control subjects without autoimmune diseases. The sera were tested for binding to activated neutrophils, deiminated histones, and neutrophil extracellular chromatin traps (NETs). IgG binding to lipopolysaccharide-activated neutrophils was assessed with confocal microscopy, and binding to in vitro-deiminated histones was measured using enzyme-linked immunosorbent assay (ELISA) and Western blotting. In addition, we quantitated histone deimination in freshly isolated neutrophils from the blood of patients and control subjects. RESULTS: Increased IgG reactivity with activated neutrophils, particularly binding to NETs, was paralleled by preferential binding to deiminated histones over nondeiminated histones by ELISA in a majority of sera from FS patients but only in a minority of sera from SLE and RA patients. Immunoblotting revealed autoantibody preference for deiminated histones H3, H4, and H2A in most FS patients and in a subset of SLE and RA patients. In patients with AAVs, serum IgG preferentially bound nondeiminated histones over deiminated histones. Increased levels of deiminated histones were detected in neutrophils from RA patients. CONCLUSION: Circulating autoantibodies in FS are preferentially directed against PAD-4-deiminated histones and bind to activated neutrophils and NETs. Thus, increased reactivity with modified autoantigens in FS implies a direct contribution of neutrophil activation and the production of NET-associated nuclear autoantigens in the initiation or progression of FS.

Neutrophil attachment via Mac-1 (αMß2; CD11b/CD18; CR3) integrins induces PAD4 deimination of profilin and histone H3.

Neutrophil adhesion to endothelia, entry into tissues and chemotaxis constitute essential steps in the immune response to infections that drive inflammation. Neutrophils bind to other cells and migrate via adhesion receptors, notably the αMß2 integrin dimer (also called Mac-1, CR3 or CD11b/CD18). Here, the response of neutrophils to integrin engagement was examined by monitoring the activity of peptidylarginine deiminase 4 (PAD4). Histone H3 deimination was strongly stimulated by manganese, an integrin-activating divalent cation, even in the absence of additional inflammatory stimuli. Manganese-induced cell attachment resulted in neutrophil swarm formation that paralleled histone deimination, whereas antibodies that impair integrin binding prevented both cell adhesion and histone deimination. Manganese treatment led to putative deimination of profilin, a protein that functions as an actin-organizing hub, as detected by two-dimensional gel electrophoresis and citrulline immunoblotting. Cl-amidine, a covalent inhibitor of PAD4, and GSK484, a specific PAD4 inhibitor, blocked profilin deimination. Neutrophil migration toward leukotriene B4 and toward synovial fluid from a rheumatoid arthritis patient were inhibited by chloramidine, thus supporting the contribution of deimination to chemotaxis. The data, based on a simplified system for integrin activation, imply a mechanism whereby integrin attachment coordinates neutrophil responses to inflammation and orchestrates deimination of nuclear and cytoskeletal proteins. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.

Trapeziectomy with Ligament Reconstruction/ Suspensionplasty Compared to Suture Tape Suspensionplasty for the Surgical Treatment of Advanced Thumb Carpometacarpal Osteoarthritis.

Purpose: Trapeziectomy with tendon reconstruction/suspensionplasty (TRS) is the most commonly performed surgical procedure in the United States for treatment of thumb carpometacarpal (CMC) osteoarthritis (OA). Trapeziectomy with suture tape suspensionplasty (STS) has been used recently at the study institution as an alternative surgical treatment option with perceived benefits of earlier return to function and reduced operative time. The purpose of this study was to compare patient outcomes following TRS versus STS for treatment of thumb CMC OA. Methods: All patients who underwent primary, isolated TRS or STS for treatment of thumb CMC OA between 1/1/2014 and 9/1/2020 were analyzed. We assessed demographics and preoperative and postoperative patient-rated outcome scores including Patient-reported outcomes measurement information system scores as well as pain outcomes, satisfaction, and appearance at a mean of 2.6 years after surgery (minimum 6 months). Time to return to work and activities was compared between groups. Bivariate statistics compared outcomes between groups. Results: Ninety-four patients were included in the final study cohort, of which 53 underwent TRS and 41 underwent STS. There were no differences in preoperative, postoperative, or final patient-rated outcome scores between groups. Patients reported high global and appearance satisfaction scores at final follow-up in both groups. Mean tourniquet time was 15 minutes (26%) shorter and return to work was on average 3 weeks faster for the STS group. Conclusions: There were no differences in postoperative patient-rated outcome scores between the STS and TRS groups. The STS group had a shorter surgical time and faster return-to-work after surgery. Type of study/level of evidence: Therapeutic III.

Surgical Treatment of Foot Drop: Patient Evaluation and Peripheral Nerve Treatment Options.

Foot drop is a common clinical condition which may substantially impact physical function and health-related quality of life. The etiologies of foot drop are diverse and a detailed history and physical examination are essential in understanding the underlying pathophysiology and capacity for spontaneous recovery. Patients presenting with acute foot drop or those without significant spontaneous recovery of motor deficits may be candidates for surgical intervention. The timing, mechanism, and severity of neural injury resulting in foot drop influence the selection of the most appropriate peripheral nerve surgery, which may include direct nerve repair, neurolysis, nerve grafting, or nerve transfer.

Surgical Treatment of Foot Drop: Pathophysiology and Tendon Transfers for Restoration of Motor Function.

Foot drop is a common condition that may impact physical function and health-related quality of life. A detailed clinical history and physical examination are critical components of the initial evaluation of patients presenting with foot drop. Patients with refractory foot drop without spontaneous recovery of motor deficits, delayed presentation greater than 12 months from injury, or neural lesions that are not amenable to or have failed nerve reconstruction may be candidates for tendon transfers to restore active ankle dorsiflexion. The modified Bridle procedure is a dynamic tendon transfer that has demonstrated excellent functional outcomes in patients with refractory foot drop.

Radiographic Cobb Angle: A Feature of Congenital Lumbar Spine Stenosis.

PURPOSE: A low cost, reproducible radiographic method of diagnosing congenital lumbar spinal stenosis (CLSS) is lacking. We hypothesized that the Cobb angle for lumbar lordosis would be smaller in patients with CLSS, based on observations in our spine clinic patient population. Here, we compared lumbar lordosis Cobb angles with the radiographic ratio method in patients with normal spine imaging, degenerative spinal stenosis, and with CLSS. MATERIALS AND METHODS: Orthopedic surgeons categorized patients with low back pain as "Normal," "Degenerative spinal stenosis," and "CLSS" based on clinical presentation and findings on lumbar magnetic resonance imaging. We included 30 patients from each cohort who had undergone lateral lumbar spine radiographs and lumbar magnetic resonance imaging. For each lateral radiograph, 2 measurement methods were used (1) 4-line lumbosacral Cobb angle between L2-S1 and (2) the ratio of the anteroposterior vertebral body diameter and spinal canal anteroposterior diameter at the L3 level. We performed logistic regression analyses of CLSS prediction by Cobb angle vs the ratio method in all three cohorts. Covariates included age, gender, and body mass index. RESULTS: The radiographic Cobb angles were smaller in CLSS patients when compared to the degenerative disease and normal cohorts: a smaller radiographic Cobb angle showed higher odds ratio (OR) of predicting CLSS diagnosis compared to the radiographic ratio when compared with degenerative disease (OR = 0.28; 95% CI: 0.11-0.78, P = 0.01) and when compared with the normal cohort (OR = 0.46; 95% CI: 0.24-0.92, P = 0.03). Radiographic ratio measurements showed no difference between the three cohorts (P = 0.12). CLSS was associated with male gender (P = 0.04), younger age (P = 0.01), and higher body mass index (P = 0.01). CONCLUSION: The radiographic Cobb angle method for lumbar lordosis may be useful for raising the possibility of CLSS as the diagnosis.

To NET or not to NET:current opinions and state of the science regarding the formation of neutrophil extracellular traps.

Since the discovery and definition of neutrophil extracellular traps (NETs) 14 years ago, numerous characteristics and physiological functions of NETs have been uncovered. Nowadays, the field continues to expand and novel mechanisms that orchestrate formation of NETs, their previously unknown properties, and novel implications in disease continue to emerge. The abundance of available data has also led to some confusion in the NET research community due to contradictory results and divergent scientific concepts, such as pro- and anti-inflammatory roles in pathologic conditions, demarcation from other forms of cell death, or the origin of the DNA that forms the NET scaffold. Here, we present prevailing concepts and state of the science in NET-related research and elaborate on open questions and areas of dispute.

Dysphagia in acute stroke: correlation with stroke subtype, vascular territory and in-hospital respiratory morbidity and mortality.

AIMS: The study aimed at correlation of post-stroke dysphagia with area and volume of infarct/ bleed, and with subsequent in-hospital respiratory morbidity and mortality. MATERIALS AND METHODS: 50 patients of acute stroke were serially recruited. Standard Staff swallowing assessment was performed within 24 hours of admission along with pulse oximetry. Ischemic strokes were classified as per OCPS registry. In-hospital respiratory morbidity and mortality, mode of nutrition and disability status at discharge were noted. RESULTS: 21/50 (42%) patients had post-stroke dysphagia during their hospital course. Among infarcts, Total Anterior Circulation Infarcts (TACI) had 100% incidence of dysphagia, followed by Partial Anterior Circulation Infarcts (PACI-36%), Posterior Circulation infarcts (POCI-33%), and Lacunar infarcts (LACI-18%). 67% of hemorrhages had post-stroke dysphagia. Staff swallowing assessment had a sensitivity and specificity of 75% and 73% respy., for predicting respiratory morbidity. The corresponding figures for Pulse oximetry were 79% and 91%.

Burning controversies in NETs and autoimmunity: The mysteries of cell death and autoimmune disease.

The causes and mechanisms of autoimmune disease pose continuing challenges to the scientific community. Recent clues implicate a peculiar feature of neutrophils, their ability to release nuclear chromatin in the form of neutrophil extracellular traps (NETs), in the induction or progression of autoimmune disease. Efforts to define the beneficial versus detrimental effects of NET release have, as yet, only partially revealed mechanisms that guide this process. Evidence suggests that the process of NET release is highly regulated, but the details of regulation remain controversial and obscure. Without a better understanding of the factors that initiate and control NET formation, the judicious modification of neutrophil behaviour for medically useful purposes appears remote. We highlight gaps and inconsistencies in published work, which make NETs and their role in health and disease a puzzle that deserves more focused attention.

B Cell Tolerance to Deiminated Histones in BALB/c, C57BL/6, and Autoimmune-Prone Mouse Strains.

Deimination, a posttranslational modification of arginine to citrulline carried out by peptidylarginine deiminases, may compromise tolerance of self-antigens. Patients with connective tissue autoimmunity, particularly rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), or Felty's syndrome, present with autoantibodies to deiminated histones (dH), which thus form a category of antibodies to citrullinated protein antigens (ACPA). In general, ACPA are a sensitive diagnostic for RA and may form in response to the release of nuclear chromatin (DNA plus dH) from granulocytes, usually referred to as neutrophil extracellular traps. The aim of this study was to examine spontaneously autoimmune mice for autoantibodies and T cell responses to dH. We compared IgG binding to deiminated and non-deiminated histones (nH) by ELISA and Western blotting in spontaneously autoimmune strains of (NZB × NZW) F1 and NZM2410 together with their derivative congenic strains, C57BL/6.Sle1 and C57BL/6.Sle1.Sle3, which display profound autoreactivity against nuclear self-antigens. The splenocyte proliferation against the two antigens was determined in the spontaneously autoimmune (NZB × NZW) F1 strain from which other autoimmune strains used in the study were derived. Immunizations with dH and nH were attempted in BALB/c mice to assess their splenocyte response. Splenocytes from BALB/c mice and from autoimmune mice at the time of conversion to autoimmunity proliferated strongly in response to dH, yet serum IgG from autoimmune (NZB × NZW) F1, NZM2410, and C57BL/6.Sle1.Sle3 mice displayed a remarkable bias against binding to dH. At the time of seroconversion, the antibodies already exhibited preference for nH, and only nH were recovered from circulating immune complexes. Analysis of histone deimination showed constitutive deimination in thymic extracts from C57BL/6 and C57BL/6.Sle1.Sle2.Sle3 triply congenic mice and in spleens of autoimmune triply congenic mice. Our study demonstrates that tolerance mechanisms against dH are intact in BALB/c and C57BL/6 mice and continue to be effective in mice with overt autoimmunity to nH. We conclude that, in contrast to human RA and SLE patients, where we frequently observe autoantibodies against dH, autoimmune mice maintain strong tolerance mechanisms to prevent the development of autoantibodies to dH.

Citrullination of NF-κB p65 promotes its nuclear localization and TLR-induced expression of IL-1ß and TNFα.

Many citrullinated proteins are known autoantigens in rheumatoid arthritis, a disease mediated by inflammatory cytokines, such as tumor necrosis factor-α (TNFα). Citrullinated proteins are generated by converting peptidylarginine to peptidylcitrulline, a process catalyzed by the peptidylarginine deiminases (PADs), including PAD1 to PAD4 and PAD6. Several major risk factors for rheumatoid arthritis are associated with heightened citrullination. However, the physiological role of citrullination in immune cells is poorly understood. We report that suppression of PAD activity attenuates Toll-like receptor-induced expression of interleukin-1ß (IL-1ß) and TNFα by neutrophils in vivo and in vitro but not their global transcription activity. Mechanistically, PAD4 directly citrullinates nuclear factor κB (NF-κB) p65 and enhances the interaction of p65 with importin α3, which brings p65 into the nucleus. The citrullination-enhanced interaction of p65 with importin α3 and its nuclear translocation and transcriptional activity can be attributed to citrullination of four arginine residues located in the Rel homology domain of p65. Furthermore, a rheumatoid arthritis-prone variant of PAD4, carrying three missense mutations, is more efficient in interacting with p65 and enhancing NF-κB activity. Together, these data not only demonstrate a critical role of citrullination in an NF-κB-dependent expression of IL-1ß and TNFα but also provide a molecular mechanism by which heightened citrullination propagates inflammation in rheumatoid arthritis. Accordingly, attenuating p65-mediated production of IL-1ß and TNFα by blocking the citrullination of p65 has great therapeutic potential in rheumatoid arthritis.

Insulin Downregulates the Transcriptional Coregulator CITED2, an Inhibitor of Proangiogenic Function in Endothelial Cells.

In patients with atherosclerotic complications of diabetes, impaired neovascularization of ischemic tissue in the myocardium and lower limb limits the ability of these tissues to compensate for poor perfusion. We identified 10 novel insulin-regulated genes, among them Adm, Cited2, and Ctgf, which were downregulated in endothelial cells by insulin through FoxO1. CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2), which was downregulated by insulin by up to 54%, is an important negative regulator of hypoxia-inducible factor (HIF) and impaired HIF signaling is a key mechanism underlying the impairment of angiogenesis in diabetes. Consistent with impairment of vascular insulin action, CITED2 was increased in cardiac endothelial cells from mice with diet-induced obesity and from db/db mice and was 3.8-fold higher in arterial tissue from patients with type 2 diabetes than control subjects without diabetes. CITED2 knockdown promoted endothelial tube formation and endothelial cell proliferation, whereas CITED2 overexpression impaired HIF activity in vitro. After femoral artery ligation, induction of an endothelial-specific HIF target gene in hind limb muscle was markedly upregulated in mice with endothelial cell deletion of CITED2, suggesting that CITED2 can limit HIF activity in vivo. We conclude that vascular insulin resistance in type 2 diabetes contributes to the upregulation of CITED2, which impairs HIF signaling and endothelial proangiogenic function.