Limited Inflammatory Response Research Articles

Age and duration of obesity modulate the inflammatory response and expression of neuroprotective factors in mammalian female brain.

Obesity has become a global epidemic and is associated with comorbidities, including diabetes, cardiovascular, and neurodegenerative diseases, among others. While appreciable insight has been gained into the mechanisms of obesity-associated comorbidities, effects of age, and duration of obesity on the female brain remain obscure. To address this gap, adolescent and mature adult female mice were subjected to a high-fat diet (HFD) for 13 or 26 weeks, whereas age-matched controls were fed a standard diet. Subsequently, the expression of inflammatory cytokines, neurotrophic/neuroprotective factors, and markers of microgliosis and astrogliosis were analyzed in the hypothalamus, hippocampus, and cerebral cortex, along with inflammation in visceral adipose tissue. HFD led to a typical obese phenotype in all groups independent of age and duration of HFD. However, the intermediate duration of obesity induced a limited inflammatory response in adolescent females' hypothalamus while the hippocampus, cerebral cortex, and visceral adipose tissue remained unaffected. In contrast, the prolonged duration of obesity resulted in inflammation in all three brain regions and visceral adipose tissue along with upregulation of microgliosis/astrogliosis and suppression of neurotrophic/neuroprotective factors in all brain regions, denoting the duration of obesity as a critical risk factor for neurodegenerative diseases. Importantly, when female mice were older (i.e., mature adult), even the intermediate duration of obesity induced similar adverse effects in all brain regions. Taken together, our findings suggest that (1) both age and duration of obesity have a significant impact on obesity-associated comorbidities and (2) early interventions to end obesity are critical to preserving brain health.

A comparative study on the effects of biodegradable high-purity magnesium screw and polymer screw for fixation in epiphyseal trabecular bone.

With mechanical strength close to cortical bone, biodegradable and osteopromotive properties, magnesium (Mg)-based implants are promising biomaterials for orthopedic applications. However, during the degradation of such implants, there are still concerns on the potential adverse effects such as formation of cavities, osteolytic phenomena and chronic inflammation. Therefore, to transform Mg-based implants into clinical practice, the present study evaluated the local effects of high-purity Mg screws (HP-Mg, 99.99 wt%) by comparing with clinically approved polylactic acid (PLA) screws in epiphyseal trabecular bone of rabbits. After implantation of screws at the rabbit distal femur, bone microstructural, histomorphometric and biomechanical properties were measured at various time points (weeks 4, 8 and 16) using micro-CT, histology and histomorphometry, micro-indentation and scanning electron microscope. HP-Mg screws promoted peri-implant bone ingrowth with higher bone mass (BV/TV at week 4: 0.189 ± 0.022 in PLA group versus 0.313 ± 0.053 in Mg group), higher biomechanical properties (hardness at week 4: 35.045 ± 1.000 HV in PLA group versus 51.975 ± 2.565 HV in Mg group), more mature osteocyte LCN architecture, accelerated bone remodeling process and alleviated immunoreactive score (IRS of Ram11 at week 4: 5.8 ± 0.712 in PLA group versus 3.75 ± 0.866 in Mg group) as compared to PLA screws. Furthermore, we conducted finite element analysis to validate the superiority of HP-Mg screws as orthopedic implants by demonstrating reduced stress concentration and uniform stress distribution around the bone tunnel, which led to lower risks of trabecular microfractures. In conclusion, HP-Mg screws demonstrated greater osteogenic bioactivity and limited inflammatory response compared to PLA screws in the epiphyseal trabecular bone of rabbits. Our findings have paved a promising way for the clinical application of Mg-based implants.

Optimization of intrauterine interventions in spontaneous abortion

Introduction. Retained products of conception (RPOC) are detected in 15 % of women after spontaneous or medical abortion. RPOC blind removal from the uterine cavity remains the "gold standard" of surgical treatment, which, however, may be associated with a high risk of certain complications that pose a serious threat to female reproductive function and quality of life. An alternative method for eliminating RPOC proposed by operative hysteroscopy demonstrating the visual control advantages.Aim: to evaluate clinical effectiveness and safety of RPOC removal in incomplete spontaneous abortion using hysteroscopic morcellation.Materials and Methods. The prospective comparative study included 135 women with incomplete spontaneous abortion aged 18 to 40 years, divided into 3 groups: group 1 – 42 patients after RPOC electromechanical vacuum aspiration (EVA); group 2 – 44 patients after RPOC manual vacuum aspiration (MVA); group 3 – 49 patients after RPOC hysteroscopic morcellation (HM). In all patients, the level of total endotoxin was measured, metroaspirate cytokine profile was analyzed, the indicator of endometrial microcirculation was assessed before surgical treatment and on day 1 afterwards, and genital ultrasound examination was performed on day 3–5 post-surgery.Results. In the post-surgical vs. pre-treatment period, the EVA and MVA groups revealed significantly increased levels of total endotoxin and interleukin (IL) IL-1β (p < 0.05). In contrast, these parameters in the HM group changed insignificantly (p > 0.05). In all groups, IL-8 and tumor necrosis factor alpha (TNF-α) levels after surgery were significantly elevated (p = 0.001). In the EVA and MVA groups, levels of anti-inflammatory cytokines IL-4 and IL-10 were markedly decreased (p = 0.001), which did not change in the HM group (p > 0.05). A significantly accelerated microcirculation rate was noted in the EVA and MVA groups while comparing it at pre-surgery level (p = 0.001), but not in the HM group (p = 0.415). Incomplete RPOC removal was reported for 4.5 % MVA patients, all EVA and HM patients had total RPOC elimination. Intraoperative bleeding, uterine perforation were not reported in any examined patient.Conclusion. The early-stage treatment results showed that RPOC removal by the HM is an effective and safe approach. Limited inflammatory response and stable endometrial microcirculation upon using the HM evidence about a minimal impact on the endometrium that lowers probability of postoperative adhesion.

Chest wall resections for sulcus superior tumors.

Chemoradiotherapy followed by surgical resection (trimodality therapy) is a guideline recommended treatment for sulcus superior tumors (SST). By definition, SSTs invade the chest wall and therefore require en-bloc chest wall resection with the upper lung lobe or segments. The addition of a chest wall resection, potentially results in higher morbidity and mortality rates when compared to standard anatomical pulmonary resection. This, together with their anatomical location in the thoracic outlet, and varying grades of fibrosis and adhesions resulting from induction chemoradiotherapy in the operation field, make surgery challenging. Depending on the exact location of the tumor and extent to which it invades the surrounding structures, the preferred surgical approach may vary, e.g., anterior, posterolateral, hemi-clamshell, or combined approach; all with their own potential advantages and morbidities. Careful patient selection, adequate staging and discussion in a multidisciplinary tumor board in a center experienced in complex thoracic oncology leads to the best long-term survival outcomes with the least morbidity and mortality. Enhanced recovery guidelines are now available for thoracic surgery, promoting faster recovery and helping to minimize complications and morbidity, including infections and thoracotomy pain. Although minimally invasive surgery can enhance recovery and reduce chest wall morbidity, and is in widespread use in thoracic oncology, its use for SST has been limited. However, this is an evolving area and hybrid surgical approaches (including use of the robot) are being reported. Chest wall reconstruction is rarely necessary, but if so, the prosthetic materials are preferably radiolucent/non-scattering, rigid enough while still being somewhat flexible, and inert, providing structural support, allowing chest wall movement, and closing defects, while inciting a limited inflammatory response. New techniques such as 3D image reconstructions/volume rendering, 3D-printing, and virtual reality modules may help pre-operative planning and informed patient consent.

In Vitro Studies on 3D-Printed PLA/HA/GNP Structures for Bone Tissue Regeneration.

The successful regeneration of large-size bone defects remains one of the most critical challenges faced in orthopaedics. Recently, 3D printing technology has been widely used to fabricate reliable, reproducible and economically affordable scaffolds with specifically designed shapes and porosity, capable of providing sufficient biomimetic cues for a desired cellular behaviour. Natural or synthetic polymers reinforced with active bioceramics and/or graphene derivatives have demonstrated adequate mechanical properties and a proper cellular response, attracting the attention of researchers in the bone regeneration field. In the present work, 3D-printed graphene nanoplatelet (GNP)-reinforced polylactic acid (PLA)/hydroxyapatite (HA) composite scaffolds were fabricated using the fused deposition modelling (FDM) technique. The in vitro response of the MC3T3-E1 pre-osteoblasts and RAW 264.7 macrophages revealed that these newly designed scaffolds exhibited various survival rates and a sustained proliferation. Moreover, as expected, the addition of HA into the PLA matrix contributed to mimicking a bone extracellular matrix, leading to positive effects on the pre-osteoblast osteogenic differentiation. In addition, a limited inflammatory response was also observed. Overall, the results suggest the great potential of the newly developed 3D-printed composite materials as suitable candidates for bone tissue engineering applications.

Single-cycle influenza virus vaccine generates lung CD8+ Trm that cross-react against viral variants and subvert virus escape mutants.

Influenza virus-specific tissue-resident memory (Trm) CD8+ T cells located along the respiratory tract provide cross-strain protection against a breadth of influenza viruses. We show that immunization with a single-cycle influenza virus vaccine candidate (S-FLU) results in the deposition of influenza virus nucleoprotein (NP)-specific CD8+ Trm along the respiratory tract that were more cross-reactive against viral variants and less likely to drive the development of cytotoxic T lymphocyte (CTL) escape mutants, as compared to the lung memory NP-specific CD8+ T cell pool established following influenza infection. This immune profile was linked to the limited inflammatory response evoked by S-FLU vaccination, which increased TCR repertoire diversity within the memory CD8+ T cell compartment. Cumulatively, this work shows that S-FLU vaccination evokes a clonally diverse, cross-reactive memory CD8+ T cell pool, which protects against severe disease without driving the virus to rapidly evolve and escape, and thus represents an attractive vaccine for use against rapidly mutating influenza viruses.

Infections in patients with acute myeloid leukemia

Infections represent one of the most frequent complications during therapy of acute myeloid leukemia (AML). In addition to associated prolonged phases of neutropenia, damage to the mucosal barrier by cytotoxic agents favors infections caused by endogenous pathogens. The source often remains unknown with bacteremia being the most common evidence of infection. Infections with gram-positive bacteria predominate, however, infections with gram-negative bacteria more often lead to sepsis and death. Due to prolonged neutropenia, patients with AML are furthermore at risk for invasive fungal infections. Viruses, on the other hand, are rarely the cause of neutropenic fever. Because of the limited inflammatory response in neutropenic patients, fever is often the only sign of infection and therefore always represents a hematologic emergency. Prompt diagnosis and initiation of an adequate anti-infective therapy are critical to avoid progression to sepsis and possibly death.

IgA2 immune complexes selectively promote inflammation by human CD103+ dendritic cells.

While immunoglobulin A (IgA) is well known for its neutralizing and anti-inflammatory function, it is becoming increasingly clear that IgA can also induce human inflammatory responses by various different immune cells. Yet, little is known about the relative role of induction of inflammation by the two IgA subclasses i.e. IgA1, most prominent subclass in circulation, and IgA2, most prominent subclass in the lower intestine. Here, we set out to study the inflammatory function of IgA subclasses on different human myeloid immune cell subsets, including monocytes, and in vitro differentiated macrophages and intestinal CD103+ dendritic cells (DCs). While individual stimulation with IgA immune complexes only induced limited inflammatory responses by human immune cells, both IgA subclasses strongly amplified pro-inflammatory cytokine production upon co-stimulation with Toll-like receptor (TLR) ligands such as Pam3CSK4, PGN, and LPS. Strikingly, while IgA1 induced slightly higher or similar levels of pro-inflammatory cytokines by monocytes and macrophages, respectively, IgA2 induced substantially more inflammation than IgA1 by CD103+ DCs. In addition to pro-inflammatory cytokine proteins, IgA2 also induced higher mRNA expression levels, indicating that amplification of pro-inflammatory cytokine production is at least partially regulated at the level of gene transcription. Interestingly, cytokine amplification by IgA1 was almost completely dependent on Fc alpha receptor I (FcαRI), whilst blocking this receptor only partially reduced cytokine induction by IgA2. In addition, IgA2-induced amplification of pro-inflammatory cytokines was less dependent on signaling through the kinases Syk, PI3K, and TBK1/IKKϵ. Combined, these findings indicate that IgA2 immune complexes, which are most abundantly expressed in the lower intestine, particularly promote inflammation by human CD103+ intestinal DCs. This may serve an important physiological function upon infection, by enabling inflammatory responses by this otherwise tolerogenic DC subset. Since various inflammatory disorders are characterized by disturbances in IgA subclass balance, this may also play a role in the induction or exacerbation of chronic intestinal inflammation.

Gene expression profiling of human macrophages after graphene oxide and graphene nanoplatelets treatment reveals particle-specific regulation of pathways

Graphene and its derivatives are attractive materials envisaged to enable a wealth of novel applications in many fields including energy, electronics, composite materials or health. A comprehensive understanding of the potential adverse effects of graphene-related materials (GRM) in humans is a prerequisite to the safe use of these promising materials. Here, we exploited gene expression profiling to identify transcriptional responses and toxicity pathways induced by graphene oxide (GO) and graphene nanoplatelets (GNP) in human macrophages. Primary human monocyte-derived macrophages (MDM) and a human macrophage cell line, i.e. differentiated THP-1 cells, were exposed to 5 or 20 μg/mL GO and GNP for 6 and 24 h to capture early and more persistent acute responses at realistic or slightly overdose concentrations. GO and GNP induced time-, dose- and macrophage type-specific differential expression of a substantial number of genes with some overlap between the two GRM types (up to 384 genes (9.6%) or 447 genes (20.4%) in THP-1 or MDM, respectively) but also a high number of genes exclusively deregulated from each material type. Furthermore, GRM responses on gene expression were highly different from those induced by inflammogenic material crystalline quartz (maximum of 64 (2.3%) or 318 (11.3%) common genes for MDM treated with 20 μg/mL GO and GNP, respectively). Further bioinformatics analysis revealed that GNP predominantly activated genes controlling inflammatory and apoptotic pathways whereas GO showed only limited inflammatory responses. Interestingly, both GRM affected the expression of genes related to antigen processing and presentation and in addition, GO activated pathways of neutrophil activation, degranulation and immunity in MDM. Overall, this study provides an extensive resource of potential toxicity mechanisms for future safety assessment of GRM in more advanced model systems to verify if the observed changes in gene expression in human macrophages could lead to long-term consequences on human health.

Research progress on the mechanism of interleukin-1β on epiphyseal plate chondrocytes

Epiphyseal plate injury, a common problem in pediatric orthopedics, may result in poor bone repair or growth defects. Epiphyseal plate, also known as growth plate is a layer of hyaline cartilage tissue between the epiphysis and metaphyseal and has the ability to grow longitudinally. Under normal physiological conditions, the epiphyseal plate has a certain axial resistance to stress, but it is fragile in growth phase and can be damaged by excessive stress, leading to detachment or avulsion of the epiphysis, resulting in life-long devastating consequences for patients. There is an obvious inflammatory response in the phase of growth plate injury, the limited physiological inflammatory response locally favors tissue repair and the organism, but uncontrolled chronic inflammation always leads to tissue destruction and disease progression. Interleukin-1β (IL-1β), as representative inflammatory factors, not only affect the inflammatory phase response to bone and soft tissue injury, but have a potentially important role in the later repair phase, though the exact mechanism is not fully understood. At present, epiphyseal plate injuries are mainly treated by corrective and reconstructive surgery, which is highly invasive with limited effectiveness, thus new therapeutic approaches are urgently needed, so a deeper understanding and exploration of the pathological mechanisms of epiphyseal plate injuries at the cellular molecular level is an entry point. In this review, we fully introduced the key role of IL-1 in the progression of epiphyseal plate injury and repair, deeply explored the mechanism of IL-1 on the molecular transcript level and endocrine metabolism of chondrocytes from multiple aspects, and summarized other possible mechanisms to provide theoretical basis for the clinical treatment and in-depth study of epiphyseal plate injury in children.

Meconium Aspiration Syndrome in Animal Models: Inflammatory Process, Apoptosis, and Surfactant Inactivation.

Meconium Aspiration Syndrome is a condition that causes respiratory distress in newborns due to occlusion and airway inflammation, and surfactant inactivation by meconium. This condition has been described in animal species such as canids, sheep, cattle, horses, pigs, and marine mammals. In its pathogenesis, the pulmonary epithelium activates a limited inflammatory response initiated by cytokines causing leukocyte chemotaxis, inhibition of phagocytosis, and pathogen destruction. Likewise, cytokines release participates in the apoptosis processes of pneumocytes due to the interaction of angiotensin with cytokines and the caspase pathway. Due to these reactions, the prevalent signs are lung injury, hypoxia, acidosis, and pneumonia with susceptibility to infection. Given the importance of the pathophysiological mechanism of meconium aspiration syndrome, this review aims to discuss the relevance of the syndrome in veterinary medicine. The inflammatory processes caused by meconium aspiration in animal models will be analyzed, and the cellular apoptosis and biochemical processes of pulmonary surfactant inactivation will be discussed.

Comparison of the Clinical and Laboratory Features of COVID and Influenza in Children.

Background and ObjectivesCoronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2 and has a clinical presentation ranging from an asymptomatic course to flu-like syndrome up to respiratory failure. Seasonal Influenza, due to the influenza viruses and very common in children, can cause symptoms similar to COVID-19. In order to identify clinical and laboratory characteristics that allow healthcare workers to differentiate COVID-19 from Influenza, we performed a systematic review of the existing literature on the pediatric age. Methods. The research was done via PubMed for articles published from March 2020 to October 2021, combining the MeSH words "COVID-19" and "Influenza" and "Children" and considering the suggestions of the PRISMA Group.ResultsThe most frequently described symptoms were fever and cough in both groups. In most studies, high fever, cough, nasal congestion or rhinorrhea, vomiting, and muscle pain were detected more frequently in the Influenza group. Regarding the value of laboratory tests, the results were mixed. Almost all studies reported significantly lower levels of C-reactive protein and procalcitonin in the COVID-19 group than in the Influenza group. In most manuscripts, COVID-19 had a milder course than Influenza.ConclusionsNo symptoms are characteristic of a single infectious agent, with flu-like disorders being the most common. In addition, laboratory tests do not help in the differential diagnosis; however, they show a limited inflammatory response in COVID-19, which could explain the fewer complications compared to adulthood, with a less severe clinical course.

Bupivacaine-loaded hydroxypropyl chitin based sponges prepared via a solvent-free process provide long-acting local anesthesia for postoperative pain

Local anesthetics have been extensively used in clinical practice to relieve the postoperative pain of patients. However, due to the short half-life of local anesthetics, a simple injection of local anesthetics cannot provide sufficient anesthetic effect for patients. It is important to develop a new delivery system for local drug administration to achieve an extended anesthetic effect without notable side effects. In this study, bupivacaine hydrochloride (BPV) loaded thermosensitive hydroxypropyl chitin (HPCH) based sponges were prepared via a simple solvent-free process for long-lasting drug release. The HPCH sponge showed good mechanical property to resist external stress and maintain the integrity, which was stronger than the collagen/HPCH composite sponge and much better than the pure collagen sponge. The HPCH sponge also displayed good biodegradability and compatibility. The BPV-loaded 2.4%-HPCH (3.6 wt%) sponge showed the most sustained release profile, and the maximal duration of in vitro release was about 8 times longer than that of the control group BPV-loaded 0.8 %-collagen (0.6 wt%) sponge based on commercial Xaracoll. More importantly, the effective duration of blockade (analgesia) of 21.67 h for the BPV-loaded 2.4 %-HPCH (3.6 wt%) sponge was much longer than that of the bupivacaine hydrochloride solution injection (1 h, 0.8 %-BPV solution) in the guinea pig pin-prick test. Hematoxylin-eosin staining data indicated that a very limited mild inflammatory response was observed at the location where the BPV-loaded HPCH (3.6 wt%) sponge was placed. Thus, the HPCH sponge is expected to serve as a promising drug carrier for the sustained release of bupivacaine in postoperative pain management.

Endotoxin tolerance induced by Porphyromonas gingivalis lipopolysaccharide alters macrophage polarization

Endotoxin tolerance refers to a state refractory to subsequent lipopolysaccharide (LPS) stimulations following a primary LPS exposure. To study the relationship between endotoxin tolerance and macrophage polarization, endotoxin tolerance was induced by 1 μg/mL LPS from the periodontal pathogen, Porphyromonas gingivalis (P. gingivalis), in peritoneal macrophages (PMs) and bone marrow-derived macrophages (BMDMs). Repeated P. gingivalis LPS challenges increased the quantities of CD206+ PMs, while the number of CD86+CD206+ PMs was reduced compared with the non-tolerant group (p < 0.05). However, there were no changes in BMDMs (p > 0.05). Down regulations of TNF-α, IL-12, nitric oxide and MMP-2 production, and upregulated IL-10, MMP-9 levels and arginase-1 activities occurred in tolerant PMs and BMDMs (p < 0.05). P. gingivalis LPS-tolerant PMs and BMDMs also enhanced scrape-wound healing abilities of 15p-1 cells (p < 0.05). Expressions of phospho-signal transducer and activator of transcription 6 (p-STAT6) and protein tyrosine phosphatase 1B (PTP1B) were increased, while p-MEK1/2 levels were downregulated in tolerant PMs and BMDMs (p < 0.05). IL-10 production in tolerant Stat6 knockdown RAW264.7 cells was lower than tolerant control cells (p < 0.05). P. gingivalis LPS-tolerant macrophages represented an intermediate state between M1/M2 polarization, which functioned as M2-like cells, and led to limited inflammatory responses and enhanced wound healing activities. The PTP1B-MEK1/2-STAT6 signaling pathway might be involved in the polarization of tolerant macrophages.

Evaluation of tribological and biological properties of TaB2/PEEK composite coatings prepared by electrodeposition

AbstractIt is well‐known that a lower wear rate, favorable mechanical properties, and limited inflammatory response are critical factors in determining the long‐term service of orthopedic implants. In this study, we prepare TaB2/PEEK coatings by electrophoretic deposition (EPD) of borated tantalum (TaB2) and polyether‐ether‐ketone (PEEK) particles on a pure titanium plate (TA2). Nanoindenter, reciprocating ball‐on‐disc tester, and in vitro biological experiments were used to investigate the effects of TaB2 particles on the mechanical properties, tribological properties, and biological properties of composite coatings. The results demonstrate that a small amount of TaB2 particles were equally dispersed in the PEEK matrix, and the mechanical properties are improved, resulting in better tribological properties of the coating. In particular, the wear rate of P‐TB‐3 coating in the simulated body fluid (SBF) was 72% lower than that of the PEEK coating, with a friction coefficient (COF) of 0.164 and a wear rate of 1.45 × 10−6 mm3·N−1 m−1, respectively. Furthermore, the P‐TB‐3 surface boosted Raw264.7 macrophage adherence and proliferation, with a potential to promote Raw264.7 macrophage transition to the M2 phenotype. These results suggest that the P‐TB‐3 coating prepared by EPD is considered as a promising implant replacement material.

Microglia Do Not Restrict SARS-CoV-2 Replication following Infection of the Central Nervous System of K18-Human ACE2 Transgenic Mice.

ABSTRACTUnlike SARS-CoV-1 and MERS-CoV, infection with SARS-CoV-2, the viral pathogen responsible for COVID-19, is often associated with neurologic symptoms that range from mild to severe, yet increasing evidence argues the virus does not exhibit extensive neuroinvasive properties. We demonstrate SARS-CoV-2 can infect and replicate in human iPSC-derived neurons and that infection shows limited antiviral and inflammatory responses but increased activation of EIF2 signaling following infection as determined by RNA sequencing. Intranasal infection of K18 human ACE2 transgenic mice (K18-hACE2) with SARS-CoV-2 resulted in lung pathology associated with viral replication and immune cell infiltration. In addition, ∼50% of infected mice exhibited CNS infection characterized by wide-spread viral replication in neurons accompanied by increased expression of chemokine (Cxcl9, Cxcl10, Ccl2, Ccl5 and Ccl19) and cytokine (Ifn-λ and Tnf-α) transcripts associated with microgliosis and a neuroinflammatory response consisting primarily of monocytes/macrophages. Microglia depletion via administration of colony-stimulating factor 1 receptor inhibitor, PLX5622, in SARS-CoV-2 infected mice did not affect survival or viral replication but did result in dampened expression of proinflammatory cytokine/chemokine transcripts and a reduction in monocyte/macrophage infiltration. These results argue that microglia are dispensable in terms of controlling SARS-CoV-2 replication in in the K18-hACE2 model but do contribute to an inflammatory response through expression of pro-inflammatory genes. Collectively, these findings contribute to previous work demonstrating the ability of SARS-CoV-2 to infect neurons as well as emphasizing the potential use of the K18-hACE2 model to study immunological and neuropathological aspects related to SARS-CoV-2-induced neurologic disease.IMPORTANCE Understanding the immunological mechanisms contributing to both host defense and disease following viral infection of the CNS is of critical importance given the increasing number of viruses that are capable of infecting and replicating within the nervous system. With this in mind, the present study was undertaken to evaluate the role of microglia in aiding in host defense following experimental infection of the central nervous system (CNS) of K18-hACE2 with SARS-CoV-2, the causative agent of COVID-19. Neurologic symptoms that range in severity are common in COVID-19 patients and understanding immune responses that contribute to restricting neurologic disease can provide important insight into better understanding consequences associated with SARS-CoV-2 infection of the CNS.

437. Longitudinal Plasma Cytokine Profiles Differentiating COVID-19 Severity Groups

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), an infection with widely varying clinical severity. Severe COVID-19 was initially proposed to be secondary to cytokine storm syndrome (CSS). However, studies since showed that patients with severe COVID-19 rarely display CSS cytokine phenotypes, and may have more limited inflammatory responses instead. MethodsProspective cohorts, aged 0-90 years of age who tested positive by polymerase chain reaction (PCR) for SARS-CoV-2 were enrolled from inpatient hospitals and outpatient testing centers in Memphis, TN from May 2020-January 2021. Longitudinal blood samples were obtained including acute, sub-acute and convalescent timepoints. Severity scores of asymptomatic, mild, moderate, and severe COVID-19 were assigned at time of convalescent assessment. Plasma was analyzed with a quantitative human magnetic 38-plex cytokine assay.Results: 169 participants were enrolled, including 8 asymptomatic, 117 mild, 22 moderate and 17 severe cases, and 5 children with post-COVID-19 multisystem inflammatory syndrome in children (MIS-C). All moderate and severe patients were hospitalized and received treatment (39%). Clear distinctions were seen between asymptomatic-mild cases and moderate-severe cases at acute timepoints and during disease progression for GCSF, IL-8, IL-10, IL-15, IL-1Ra, IP-10, MIP-1a, MIP-1β, and TGFα. There was a significant difference between participants who did and did not require hospitalization for acute timepoint levels of IL-10, IL-15, MIP-1 β and TGFα (p< 0.01). Only 4 participants with active COVID-19 were found to meet criteria for CSS (2%), only 3 of which were severe. MIS-C participants showed nearly universally elevated cytokine levels compared to those with active COVID-19. Temporal and severity associations of IL-10 and IP-10 Figure 1. Temporal and severity associations of IL-10 and IP-10 Examples of differentiating cytokine profiles by severity and time. Among SARS-CoV-2 PCR positive participants, IL-10 and IP-10 displayed increased levels in their acute plasma samples as clinical severity increased [A,C]. IL-10 and IP-10 also showed distinct time-dependent responses (ln(Cytokine level (pg/mL)) that differentiated the more severe from the less severe groups [B,D].ConclusionModerate and severe acute COVID-19 has a distinct cytokine profile from asymptomatic and mild cases, as detected from acute, subacute and convalescent plasma.Disclosures Joshua Wolf, MBBS, PhD, FRACP, Karius Inc. (Research Grant or Support) Joshua Wolf, MBBS, PhD, FRACP, Nothing to disclose Paul Thomas, PhD, Cytoagents (Consultant)Immunoscape (Consultant)

Transscleral cyclophotocoagulation with MicroPulse® laser versus cyclophotocoagulation with continuous diode laser in patients with open-angle glaucoma.

To present the efficacy and safety of surgical treatment of moderate to advanced stage of open-angle glaucoma using the surgical method of transscleral cyclophotocoagulation with MicroPulse® laser (Iridex, Silicon Valley, California, USA) and to compare these results with those of continuous transscleral cyclophotocoagulation with diode laser. In a prospective observational clinical study 22 patients (30 eyes) with moderate and advanced open-angle glaucoma underwent transscleral cyclophotocoagulation. 15 eyes were treated with transscleral cyclophotocoagulation with MicroPulse® laser with 2500 mW (group A) and 15 eyes with continuous diode laser 810nm and power between 2000 and 2300 mW (group B). The follow-up period of the study was 12months. A reduction of the intraocular pressure > 30% was achieved in 53.3% of the group A and in 60% of the group B during the follow-up period of 12months. A statistically significant decrease of the number of antiglaucoma agents was observed in group A. One eye (6.6%) of group A underwent additional antiglaucoma procedures to achieve target intraocular pressure. The corresponding percentage is 40% in group B. The postoperative inflammatory response was significantly more limited in group A compared to group B. The transscleral cyclophotocoagulation with MicroPulse® diode laser with 2500 mW achieves a similar decrease of the intraocular pressure as cyclophotocoagulation with continuous diode laser for the first postoperative months, but more satisfactory reduction of the number of eye drops as well as more limited postoperative inflammatory response.

Atypical imaging presentation of herpes simplex virus encephalitis in paediatric immunocompromised oncology patients.

We aim to assess the imaging manifestations of brain involvement in paediatric immunocompromised patients with haematological malignancies on chemotherapy presenting with encephalitis and positive HSV CSF PCR. We also aim to determine whether our findings are similar or different to those described in literature for paediatric patients in general. A retrospective study was performed in paediatric ALL/lymphoma patients on chemotherapy, and cases with positive CSF HSV-PCR with at least one head MRI scan were included. On imaging, location(typical/atypical), post-contrast enhancement and haemorrhage/diffusivity/gliosis were evaluated. A total of 28 scans were included in study from 16 patients fulfilling inclusion criteria, 12 (75%) HSV-1 and 4 (25%) HSV-2. Of the 16 initial scans (CT n = 10, MRI n = 6), 11 were normal (CT = 7, MRI = 4). Fourteen patients had follow-up MRI, of which two had normal scans. On the abnormal initial scan (5/16), only 20% had typical medial temporal/inferomedial frontal/cingulate involvement. Most had frontal (80%), parietal (60%) and non-medial temporal (40%) lesions. Abnormal diffusivity/haemorrhage was absent in all, and postcontrast enhancement was seen in 20%. On follow-up, more patients (33%) had typical medial temporal/inferomedial frontal/cingulate involvement. Widespread atypical site involvement of frontoparietal (75%), thalamus (58%), non-medial temporal (50%), occipital/basal ganglia (33%) and cerebellum (8%) was noted. Most lesions were cortical (91%)/subcortical (75%) with few periventricular lesions (58%). Few showed abnormal diffusivity (16%), post-contrast parenchymal enhancement/haemorrhage (8%), post-contrast meningeal enhancement (25%) and gliosis (16%). Immunocompromised paediatric patients with haematological malignancies have widespread atypical brain involvement in herpes simplex encephalitis with lack of diffusion restriction and post-contrast enhancement, likely due to haematogenous spread of HSV across the blood-brain barrier, lack of cellular immunity and limited inflammatory cytokine response.

Biomarkers for severe COVID-19.

Biomarkers for severe COVID-19.