Fibrinogen Deposition Research Articles

P11 Lubricant-infused silver-polytetrafluoroethylene coated urinary catheters inhibit adhesion of host-secreted proteins and biofilm formation

Abstract Objectives The adhesion of specific host-derived proteins (particularly fibrinogen) and subsequent biofilm formation play a central role in the pathogenesis of catheter-associated urinary catheter infections (CAUTIs). However, very few catheter materials have proven to be able to simultaneously prevent both bacterial and protein adhesion in a complex physiological environment (i.e. urine). The aims and objectives of this research were to (i) develop silver-polytetrafluoroethylene (AgF)-based coatings with a wide range of surface energies; (ii) test their antifouling performance; and (iii) investigate the influence of surface energy on biofouling accumulation. Methods Standard AgF coatings with tailored surface energies (ranging from 18 mJ/m2 to 42 mJ/m2) were fabricated using an electroless method. By spontaneous polycondensation 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) onto the AgF sublayer, a lubricant-infused AgF coating (AgFP) was obtained. The surface morphology, chemical composition, and roughness were characterized by SEM, EDS and AFM, respectively. The surface energy was characterized using a contact angle approach and calculated using the Van Oss method. The anti-adhesion performance of the coated catheters against proteins (fibrinogen [Fgn]; BSA) and bacteria (Escherichia coli; Proteus mirabilis) was examined and compared with commercial all-silicone catheters. Results The results showed that there exist two separate optimum surface energies where bacterial (∼25 mJ/m2) and protein adhesion (∼35 mJ/m2) are minimal (Figure 1). The deposition of fibrinogen on surfaces significantly accelerated bacterial attachment and biofilm formation, whereas the AgFP coating with the smoothest surface and ultralow surface energy (∼12 mJ/m2) displayed significant antibiofilm and anti-protein activities compared with uncoated silicone surface traditional AgF coatings (Figure 2). Figure 1.Surface energy on adhesion of bacteria and proteins. Figure 2.Biofilm formation on Si, AgF and AgFP surfaces after 1 day co-culture in pure bacterial suspension and protein-supplemented bacterial suspension. Scale bars correspond to 40 μm. Conclusions The inclusion of lubricant into the AgF matrix leads to the formation of a smooth and super-repelling catheter surface, leading to ultralow adhesion for both bacteria and proteins. Surprisingly, our results indicated that there exists an optimum surface energy where the adhesion of both bacteria and proteins is minimal, which further extended the classic ‘Baier curve’.

Cellular mechanisms of fibrin (ogen): insight from neurodegenerative diseases.

Neurodegenerative diseases are prevalent and currently incurable conditions that progressively impair cognitive, behavioral, and psychiatric functions of the central or peripheral nervous system. Fibrinogen, a macromolecular glycoprotein, plays a crucial role in the inflammatory response and tissue repair in the human body and interacts with various nervous system cells due to its unique molecular structure. Accumulating evidence suggests that fibrinogen deposits in the brains of patients with neurodegenerative diseases. By regulating pathophysiological mechanisms and signaling pathways, fibrinogen can exacerbate the neuro-pathological features of neurodegenerative diseases, while depletion of fibrinogen contributes to the amelioration of cognitive function impairment in patients. This review comprehensively summarizes the molecular mechanisms and biological functions of fibrinogen in central nervous system cells and neurodegenerative diseases, including Alzheimer's disease, Multiple Sclerosis, Parkinson's disease, Vascular dementia, Huntington's disease, and Amyotrophic Lateral Sclerosis. Additionally, we discuss the potential of fibrinogen-related treatments in the management of neurodegenerative disorders.

P13 A rare case of Sjögren syndrome in a White woman with Kikuchi–Fujimoto disease

Abstract A 36-year-old White woman was seen in May 2022 for a rash on her upper back, shoulders, cheeks, forehead and extensor surfaces of the upper limbs. It had developed following sun exposure on the beach despite regularly applying SPF50. Over time, the rash became sore but exhibited no signs of vesicles or oozing. Of note, the patient had been recently diagnosed with Kikuchi–Fujimoto disease (KFD) following a lymph node biopsy. She gave history of Raynaud phenomenon since childhood, and arthralgia primarily affecting the small joints of hands. She also experienced episodic dry eyes, dry mouth, peripheral oedema, dyspnoea, abdominal pain and constipation. For the previous month, she had felt fatigued with some undocumented weight loss. Clinical examination revealed an erythematous rash with discrete nonblanching macules and plaques of varying sizes, oval-to-circular in shape, on the involved areas. Lymph nodes were not palpable. Differential diagnosis included cutaneous lupus, other connective tissue disorders, and—less likely—polymorphic light eruption. Skin biopsy showed focal compact hyperkeratosis and parakeratosis with focal subtle spongiosis, intraepidermal neutrophils and lymphocyte exocytosis, with the presence of perivascular and periappendageal chronic inflammation. There was mild basement membrane thickening with focal deposition of fibrinogen at the basement membrane zone on direct immunofluorescence. She was positive for anti-Ro antibodies, with a titre of 84 kU L−1 (normal < 11 kU L−1). A diagnosis of Sjögren syndrome with KFD was made. The patient was advised on photoprotection with a high-potency topical steroid, and referred to rheumatology for review of her joint problems. After 4 weeks, the patient had only some improvement with topical therapy and was started on oral hydroxychloroquine. At the 12-week follow-up, there was significant improvement. Her skin was clear, with improvement in joint pain and fatigue. KFD, also known as necrotizing lymphadenitis, is a benign and self-limited disorder, characterized by regional cervical lymphadenopathy with tenderness, usually accompanied with mild fever and night sweats. Rarely, the skin and joints are involved. There is an established association between KFD and connective tissue disorders, especially Sjögren syndrome (Gates GA, Li Y, Magyar C, Sarantopoulos GP. Kikuchi–Fujimoto disease with unusual cutaneous findings. Am J Dermatopathol 2021; 43:e213–17). This is more prevalent among Asians and rarely reported in White people (Perry AM, Choi SM. Kikuchi-Fujimoto disease: a review. Arch Pathol Lab Med 2018; 142:1341–6), where it may cause diagnostic difficulties. This case highlights the importance of lateral thinking while formulating a differential diagnosis, despite the time pressures of a busy clinic. Although the reported prevalence of KFD among White people has been negligible (Perry et al.), it should not be dismissed solely based on a patient’s ethnicity. Timely and adequate management of rare conditions can reduce patient morbidity and improve their quality of life.

BIO10: Novel Method of Extracorporeal Membrane Oxygenator Histology

Background: Despite systemic anticoagulation, loss of function of the artificial lung (e.g., oxygenator) remains common. Moreover, the exchange of these artificial organs can be life-threatening as they interrupt continuous support. Current research suggests that cellular activation leading to thrombosis, cellular debris, or hollow-fiber breakdown may be cause of circuit occlusion. The purpose of this study is to develop a method to quantify cellular deposition to determine the source of oxygenator failure. Methods: Seven Getinge Quadrox-iD and one Medtronic Nautilus oxygenators were collected after component failure. Oxygenators were rinsed with saline, fixed with an ethanol-based solution and frozen for processing. The oxygenators were then dissected, and oxygenator fibers were sampled randomly from the inlet surface. Samples were imbedded in an optimum cutting temperature compound, frozen, sliced to 25 mm sections and mounted using a novel ultraviolet tape transfer system. Nucleated cells, fibrinogen, platelets, and proteins for DNA expression (Histone 3) and clot initiation (tissue factor) were stained using immunofluorescence. A square-root transformation was used to normalize all the fluorescence data. Results: There was no difference in gross cell deposition or clot between the Getinge or Medtronic oxygenators. The average nucleated cell count was 102 (min: 4.00; max 546) surrounding a cross-section of an oxygenator hollow-fiber. Fibrinogen deposition was increased in distal sections compared to sections obtained closer to the blood inlet (p < 0.01). Histone 3 was also increased in the distal sections compared to sections closer to the blood inlet (p < 0.03). Tissue factor expression was greater in the oxygenators obtained from patients on venovenous compared to venoarterial support (p < 0.03). Conclusion: Improving understanding of oxygenator failure needs protocolized assessments of the hollow fibers that provide gas exchange. This method of dissection maintains the architecture of the hollow-fiber providing reproducible cellular deposition data and the opportunity for multiple modes of analysis. Quantitative histological evaluation of oxygenator membranes may provide important information to evaluate novel coatings and anticoagulants.Figure 1. Immunofluorescent stain of hollow fiber oxygenator tube with cellular deposition. Leukocytes stained with blue (DAPI), fibrinogen stained green, and platelets (CD61) stained red.

O043 Evaluation of minimal factor H therapy administered to kidneys during ex vivo normothermic perfusion as a treatment to improve ischaemia reperfusion injury

Abstract Introduction Complement activation is a key mechanism of Ischaemia reperfusion injury, with the alternative pathway driving damage in particular. The main regulator of the alternative pathway is factor H. We hypothesised that homodimeric mini-factor H (HDM-FH; PMID:29588430) may protect transplanted kidneys from complement mediated damage when administered during normothermic perfusion machine perfusion. Methods Kidneys were retrieved from female white landrace pigs following an optimised protocol. One kidney from each pair was randomised to receive 5mg of HDM-FH (∼8μg/mL). Kidneys were perfused at 37°C with autologous blood for 6 hours. HDM-FH binding was measured using ELISA and immunofluorescence. Complement activation was measured by quantifying Bb deposition in tissue. The ability of HDM-FH to inhibit complement in serum was measured using haemolytic assays. Results 4mgs of HDM-FH bound from perfusate during perfusion, with &amp;lt;10% lost in urine suggesting saturation was achieved. HDM-FH binding within the kidneys was confirmed using immunofluorescence. HDM-FH localised to glomeruli with deposition increasing over the time of the perfusion. Alternative pathway activation was reduced in kidneys receiving HDM-FH as demonstrated by reduced Bb deposition. Fibrinogen deposition was also reduced and found to colocalise with C3 in glomeruli. HDM-FH inhibits complement activity in serum in a dose-dependent manor. Conclusion Infusion with HDM-FH prior to simulated kidney transplant conditions reduced complement activation and other secondary negative outcomes to the organ. Therefore, organ perfusion with HDM-FH is highly likely to help prolong graft survival after transplant and this will be assessed in future studies.

371 Fractalkine isoforms using gene therapy differentially regulate microglia activation and vascular damage in the diabetic retina

OBJECTIVES/GOALS: Retinal inflammation caused by the activation of resident macrophages (microglia) during diabetes exacerbates glial cell dysfunction, resulting in neuronal loss. The goal is to use rAAV gene therapy to deliver neuronal-derived fractalkine (FKN), minimizing inflammation and vascular damage in the diabetic retina. METHODS/STUDY POPULATION: The human microglial receptor (CX3CR1) binds to FKN, a protein that is expressed on neuronal membranes (mFKN), and undergoes constitutive cleavage to release a soluble domain (sFKN). Deficiencies in CX3CR1 or FKN showed increased microglial activation and elevated retinal pathology. To understand the mechanism by which mFKN and sFKN regulate microglia function, recombinant adeno-associated viruses (rAAVs) expressing mFKN or sFKN were delivered to intact retinas during diabetes. Markers of neuronal loss, vascular damage, and inflammation were analyzed. We hypothesize that the administration of rAAV-sFKN but not rAAV-mFKN will prevent vascular and neuronal damage, and improve visual function. RESULTS/ANTICIPATED RESULTS: rAAV-sFKN minimized microglial activation, blood vessel rupture, fibrinogen deposition, and prevented neuronal loss, compared to mice treated with rAAV-mFKN in a mouse model of diabetic retinopathy (DR). rAAV-sFKN treated mice showed improved visual acuity using a two-choice discrimination task through learning-based behavior. rAAV-sFKN treatment correlated with the success rate of the mice finding the reward based on their ability to distinguish visual cues. Future studies will test the effects of rAAV-sFKN and rAAV-mFKN on microglia inflammatory cytokine release, optic nerve damage and synaptic neurotransmission, peripheral immune responses, and transcriptomic changes in microglia during diabetes. DISCUSSION/SIGNIFICANCE: Current therapies for DR are ineffective in restoring vision. rAAVs-sFKN delivery appears to act as a neuroprotective approach in the diabetic retina. sFKN serves as an alternative pathway to implement translational and therapeutic approaches, minimizing pathology and improving visual function.

Der Lichen planus des Ösophagus – Eine unterschätzte Erkrankung

An involvement of the esophagus in patients with lichen planus was described for the first time in 1982. Ever since, it has been seen as a rarity. However, studies over the last 10 years have shown a higher prevalence than expected. It may even be supposed that esophageal lichen planus (ELP) is more common than eosinophilic esophagitis. ELP mostly affects middleaged women. The principal symptom is dysphagia. Endoscopically, ELP is characterized by denudation and tearing of the mucosa, trachealization and hyperkeratosis and esophageal stenosis may occur in patients with long courses of the disease. Histologic findings including mucosal detachment, T-lymphocytic infiltrate, intraepithelial apoptosis (civatte bodies) and dyskeratosis are crucial. Direct immunofluorescence shows fibrinogen deposits along the basement membrane zone. So far, there is no well-established therapy but a treatment with topic steroids is effective in 2/3 of the patients. Common therapy of lichen planus of the skin seems to be ineffective for treatment of ELP. Symptomatic esophageal stenosis should be endoscopically dilated. ELP joins the group of "new" immunologic diseases of the esophagus.

Difficulties in the Diagnosis of Fibrinogen Aα-Chain Amyloidosis—Literature Review and Case Report of a Patient After Kidney Transplantation

Amyloidosis is a very heterogeneous disease. Correct diagnosis is extremely important because of the various treatment options for different types of amyloidosis. This study presents a case report and literature review of the misdiagnosis of fibrinogen Aα-chain amyloidosis (AFib amyloidosis). We report a 65-year-old man diagnosed with proteinuria in 2009. The kidney biopsy revealed the presence of Congo red-stained amyloid deposits. During differential diagnosis, amyloid deposits were discovered in adipose tissue and gingiva. Bone marrow trephine biopsy showed a predominance of lambda chains presenting plasmocytes. Based on performed medical examination, light chain amyloidosis was identified. Therefore, the patient received high-dose melphalan and underwent successful autologous peripheral blood stem cell transplantation. However, proteinuria, worsening of the kidneys' function, and incorrect levels of free light chains were still observed. In 2019, due to continuous treatment failure, a previously acquired kidney biopsy was examined by mass spectrometry, and numerous fibrinogen deposits were identified. Recommended DNA analysis revealed that the patient had AFib amyloidosis. Therefore, chemotherapy treatment was abandoned, and successful kidney transplantation was performed. Today, it is essential for medical practitioners to remember the possibility of rare and hereditary types of amyloidosis. There are multiple cases where a diagnosis was wrong or delayed because of the atypical course of the disease, the coexistence of another disease, and the rarity of AFib amyloidosis, and all of these reasons may result in the wrong treatment that will delay the right therapy. However, with the new, more precise diagnostics methods, such situations will become rare.

Pharmacological depletion of microglia alleviates neuronal and vascular damage in the diabetic CX3CR1-WT retina but not in CX3CR1-KO or hCX3CR1I249/M280-expressing retina.

Diabetic retinopathy, a microvascular disease characterized by irreparable vascular damage, neurodegeneration and neuroinflammation, is a leading complication of diabetes mellitus. There is no cure for DR, and medical interventions marginally slow the progression of disease. Microglia-mediated inflammation in the diabetic retina is regulated via CX3CR1-FKN signaling, where FKN serves as a calming signal for microglial activation in several neuroinflammatory models. Polymorphic variants of CX3CR1, hCX3CR1I249/M280 , found in 25% of the human population, result in a receptor with lower binding affinity for FKN. Furthermore, disrupted CX3CR1-FKN signaling in CX3CR1-KO and FKN-KO mice leads to exacerbated microglial activation, robust neuronal cell loss and substantial vascular damage in the diabetic retina. Thus, studies to characterize the effects of hCX3CR1I249/M280 -expression in microglia-mediated inflammation in the diseased retina are relevant to identify mechanisms by which microglia contribute to disease progression. Our results show that hCX3CR1I249/M280 mice are significantly more susceptible to microgliosis and production of Cxcl10 and TNFα under acute inflammatory conditions. Inflammation is exacerbated under diabetic conditions and coincides with robust neuronal loss in comparison to CX3CR1-WT mice. Therefore, to further investigate the role of hCX3CR1I249/M280 -expression in microglial responses, we pharmacologically depleted microglia using PLX-5622, a CSF-1R antagonist. PLX-5622 treatment led to a robust (~70%) reduction in Iba1+ microglia in all non-diabetic and diabetic mice. CSF-1R antagonism in diabetic CX3CR1-WT prevented TUJ1+ axonal loss, angiogenesis and fibrinogen deposition. In contrast, PLX-5622 microglia depletion in CX3CR1-KO and hCX3CR1I249/M280 mice did not alleviate TUJ1+ axonal loss or angiogenesis. Interestingly, PLX-5622 treatment reduced fibrinogen deposition in CX3CR1-KO mice but not in hCX3CR1I249/M280 mice, suggesting that hCX3CR1I249/M280 expressing microglia influences vascular pathology differently compared to CX3CR1-KO microglia. Currently CX3CR1-KO mice are the most commonly used strain to investigate CX3CR1-FKN signaling effects on microglia-mediated inflammation and the results in this study indicate that hCX3CR1I249/M280 receptor variants may serve as a complementary model to study dysregulated CX3CR1-FKN signaling. In summary, the protective effects of microglia depletion is CX3CR1-dependent as microglia depletion in CX3CR1-KO and hCX3CR1I249/M280 mice did not alleviate retinal degeneration nor microglial morphological activation as observed in CX3CR1-WT mice.

Striatal fibrinogen extravasation and vascular degeneration correlate with motor dysfunction in an aging mouse model of Alzheimer's disease.

Introduction: Alzheimer's Disease (AD) patients exhibit signs of motor dysfunction, including gait, locomotion, and balance deficits. Changes in motor function often precede other symptoms of AD as well as correlate with increased severity and mortality. Despite the frequent occurrence of motor dysfunction in AD patients, little is known about the mechanisms by which this behavior is altered. Methods and Results: In the present study, we investigated the relationship between cerebrovascular impairment and motor dysfunction in a mouse model of AD (Tg6799). We found an age-dependent increase of extravasated fibrinogen deposits in the cortex and striatum of AD mice. Interestingly, there was significantly decreased cerebrovascular density in the striatum of the 15-month-old as compared to 7-month-old AD mice. We also found significant demyelination and axonal damage in the striatum of aged AD mice. We analyzed striatum-related motor function and anxiety levels of AD mice at both ages and found that aged AD mice exhibited significant impairment of motor function but not in the younger AD mice. Discussion: Our finding suggests an enticing correlation between extravasated fibrinogen, cerebrovascular damage of the striatum, and motor dysfunction in an AD mouse model, suggesting a possible mechanism underlying motor dysfunction in AD.

Glomerular deposition of fibrinogen predicts good prognosis of IgA nephropathy: a single-center cohort study

PurposeIt has been proven that fibrinogen deposition exists in IgA nephropathy (IgAN), but its clinical significance has not been identified. We aim to investigate the clinical implication of fibrinogen deposition in evaluating the activity and prognosis of IgA nephropathy.MethodsIn this cohort, 935 adult IgAN patients were divided into 3 groups according to the intensity of glomerular fibrinogen deposition. Primary outcome refers to a composite event of either a ≥ 50% reduction in eGFR or ESRD (eGFR < 15 ml/min/1.73m2, dialysis, or renal transplantation). Factors associated with fibrinogen deposition and prognosis were identified.ResultsThe results showed that the intensity of fibrinogen deposition was positively correlated with eGFR (P < 0.001), serum albumin (P = 0.041), and hemoglobin levels (P < 0.05), but negatively correlated with age (P = 0.04), serum fibrinogen levels (P < 0.001), serum C4 (P = 0.023), the proportion of patients with hypertension (P = 0.003), and the percentage of glomeruli sclerosis (P < 0.001). The prognostic analyses identified that fibrinogen deposition was an independent predictor for the progression of IgAN (P = 0.033).ConclusionOur study indicated that the deposition of renal fibrinogen can predict the prognosis of IgAN with high reliability.

Discovery of a polymer resistant to bacterial biofilm, swarming, and encrustation.

Innovative approaches to prevent catheter-associated urinary tract infections (CAUTIs) are urgently required. Here, we describe the discovery of an acrylate copolymer capable of resisting single- and multispecies bacterial biofilm formation, swarming, encrustation, and host protein deposition, which are major challenges associated with preventing CAUTIs. After screening ~400 acrylate polymers, poly(tert-butyl cyclohexyl acrylate) was selected for its biofilm- and encrustation-resistant properties. When combined with the swarming inhibitory poly(2-hydroxy-3-phenoxypropyl acrylate), the copolymer retained the bioinstructive properties of the respective homopolymers when challenged with Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Urinary tract catheterization causes the release of host proteins that are exploited by pathogens to colonize catheters. After preconditioning the copolymer with urine collected from patients before and after catheterization, reduced host fibrinogen deposition was observed, and resistance to diverse uropathogens was maintained. These data highlight the potential of the copolymer as a urinary catheter coating for preventing CAUTIs.

Enhanced anti-biofilm and anti-protein adsorption properties of liquid-infused silver-polytetrafluoroethylene coatings

In this work, a slippery liquid-infused silver-polytetrafluoroethylene (AgFP) coating was fabricated via a spontaneous polycondensation of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) onto an electroless AgF sublayer. The AgFP coating demonstrated great stability and superior repellence against liquids with a wide range of surface tensions. The anti-biofouling properties were investigated by adsorption of Escherichia coli, Staphylococcus aureus, fibrinogen, and bovine serum albumin. Owing to the self-cleaning property, the AgFP demonstrated enhanced anti-adhesion activity against both bacteria and proteins relative to traditional electroless coatings, despite the fibrinogen deposition significantly promoting bacterial binding. While its ultra-low surface energy was not within the optimum surface energy region for minimum bacterial or protein adhesion, the AgFP coating still displayed excellent anti-biofilm capability in a protein-bacteria co-deposition model, reducing over 80% of BSA-supplemented biomass coverage on Ag surfaces and over 60% of Fgn-supplemented biomass coverage on AgF surfaces, respectively. To understand the anti-adhesion mechanism, the XDLVO model was used to explain the adhesion behaviour of both bacteria and proteins. Cytotoxicity assays confirmed that the AgFP coating had good biocompatibility with fibroblast cells. The results from this research provide attractive prospects for the application of the AgFP coating in biomedical devices to combat infections.

Clinical, histological and direct immunofluorescence features in oral mucosal patches striae diseases with malignant potential

Background/purposeOral mucosal patches striae diseases (OMPSD) represent an important category of oral mucosal disease, most of which may have malignant potential (OMPSD-MP). The differential diagnosis is challenging due to overlap of their clinical and pathological features. Materials and methods116 OMPSD-MP patients were included in this cross-sectional study from November 2019 to February 2021, including oral lichen planus (OLP), oral lichenoid lesions (OLL), discoid lupus erythematosus (DLE), oral submucous fibrosis (OSF) and oral leukoplakia (OLK). The general information, clinical manifestation, histopathological and direct immunofluorescence (DIF) features were statistically analyzed and compared. ResultsOLP was the major type of OMPSD-MP (64.7%), followed by OLL (25.0%), OLK (6.0%), DLE (2.6%) and OSF (1.7%), which were pooled as non-OLP group for further assessment. They shared many clinical and histological features in common. The rate of clinical-pathological diagnosis concordance was 73.5% for OLP, and 76.7% for total OMPSD-MP. DIF positive rate was significantly higher in OLP group than non-OLP group (76.0% vs. 41.5%, P < 0.001), in which the deposition of fibrinogen (Fib) and IgM were most frequently found. ConclusionA significant overlap in clinical and histopathological features of OMPSD-MP was found, while DIF could be useful in differential diagnosis. Fib and IgM might be important immunopathological factors in OLP, which need further exploration.

Models of microglia depletion and replenishment elicit protective effects to alleviate vascular and neuronal damage in the diabetic murine retina

Microglia, the resident phagocytes of the retina, are believed to influence the development of retinopathy, but their exact contributions to vascular integrity and neuronal loss are unknown. Therefore, utilizing two models of microglia depletion, we aimed to deplete and repopulate microglia to clarify the contribution of microglia to neuronal loss and vascular damage in the diabetic retina in an STZ-induced model of hyperglycemia. Here, we report that 2 weeks exposure to diphtheria toxin (DTx) in diabetic CX3CR1CreER:R26iDTR transgenic mice induced a 62% increase in Iba1+ microglia associated with an increase in TUJ1+ axonal density and prevention of NeuN+RBPMS+ neuronal loss. Conversely, diabetic PBS controls exhibited robust TUJ1+ axonal and NeuN+RBPMS+ neuronal loss compared to non-diabetic controls. A 2-week recovery period from DTx was associated with a 40% reduction in angiogenesis and an 85% reduction in fibrinogen deposition into the diabetic retina in comparison to diabetic PBS-treated controls. Analysis of microglia morphology and marker expression revealed that following a 2-week recovery period microglia displayed a P2RY12+Ly6C– phenotype and high transformation index (TI) values complimented by a ramified-surveillant morphology closely resembling non-diabetic controls. In contrast, diabetic PBS-treated control mice displayed P2RY12+Ly6C+ microglia, with a 50% reduction in TI values with an amoeboid morphology. To validate these observations were due to microglia depletion, we used PLX-5622 to assess vascular and neuronal damage in the retinas of diabetic mice. Confocal microscopy revealed that PLX-5622 also induced an increase in TUJ1+ axonal density and prevented fibrinogen extravasation into the diabetic retina. mRNAseq gene expression analysis in retinal isolates revealed that PLX-5622-induced microglia depletion and repopulation induced a downregulation in genes associated with microglial activation and phagocytosis, B2m, Cx3cr1, and Trem2, and complement-associated synaptic pruning, C1qa, C1qb, and C1qc. Although the levels of microglia depletion induced with DTx in the CX3CR1CreER:R26iDTR model and those induced with the CSF-1R antagonists are distinct, our results suggest that microglia depletion and replenishment is neuroprotective by inducing the proliferation of a homeostatic microglia pool that supports neuronal and vascular integrity.

Esophageal lichen planus: Current knowledge, challenges and future perspectives.

Lichen planus (LP) is a frequent, chronic inflammatory disease involving the skin, mucous membranes and/or skin appendages. Esophageal involvement in lichen planus (ELP) is a clinically important albeit underdiagnosed inflammatory condition. This narrative review aims to give an overview of the current knowledge on ELP, its prevalence, pathogenesis, clinical manifestation, diagnostic criteria, and therapeutic options in order to provide support in clinical management. Studies on ELP were collected using PubMed/Medline. Relevant clinical and therapeutical characteristics from published patient cohorts including our own cohort were extracted and summarized. ELP mainly affects middle-aged women. The principal symptom is dysphagia. However, asymptomatic cases despite progressed macroscopic esophageal lesions may occur. The pathogenesis is unknown, however an immune-mediated mechanism is probable. Endoscopically, ELP is characterized by mucosal denudation and tearing, trachealization, and hyperkeratosis. Scarring esophageal stenosis may occur in chronic courses. Histologic findings include mucosal detachment, T-lymphocytic infiltrations, epithelial apoptosis (Civatte bodies), dyskeratosis, and hyperkeratosis. Direct immuno-fluorescence shows fibrinogen deposits along the basement membrane zone. To date, there is no established therapy. However, treatment with topical steroids induces symptomatic and histologic improvement in two thirds of ELP patients in general. More severe cases may require therapy with immunosuppressors. In symptomatic esophageal stenosis, endoscopic dilation may be necessary. ELP may be regarded as a precancerous condition as transition to squamous cell carcinoma has been documented in literature. ELP is an underdiagnosed yet clinically important differential diagnosis for patients with unclear dysphagia or esophagitis. Timely diagnosis and therapy might prevent potential sequelae such as esophageal stenosis or development of invasive squamous cell carcinoma. Further studies are needed to gain more knowledge about the pathogenesis and treatment options.

Progressive ascending telangiectasias

Progressive ascending telangiectasias

Fibrinogen Depletion Ameliorates Inflammation and Vision Loss in Mouse Models of Diabetes

Abstract Microglia-mediated inflammation plays a significant role in neuronal and vascular damage in diabetic retinopathy, but the mechanism linking inflammation, neurodegeneration, and impaired vascular integrity is still unclear. Our previous studies from diabetic mouse models showed accumulation of fibrinogen, at vessel lesions surrounded by perivascular microglial clusters. In this study, we evaluated whether the pathological hallmarks of gliosis and vascular aberrations characterized in diabetic animal models are consistent with those in diabetic human retinas. Postmortem human retinas were analyzed by immunohistochemistry for markers of gliosis, vascular integrity, and fibrinogen deposition. Immunohistochemical and gene expression analyses of human postmortem retinas revealed evidence of an inflammatory microenvironment, with microgliosis and impaired vasculature. To define the therapeutic potential of reducing fibrinogen in DR, the defibrinogenating agent ancrod was administered in a two-hit inflammatory diabetic mouse model, after which retinal pathology and visual acuity were assessed. Histopathological analyses revealed microglial activation, vascular aberrations, and fibrinogen deposition in the diabetic murine retina. Notably, after treatment with ancrod, diabetic mice appeared to improve visual acuity, which was associated with reduced microglia activation and less fibrinogen deposition in the retina. This study shows that fibrinogen-mediated microglial activation, blood-retinal barrier damage, and vision loss, can be ameliorated by reducing fibrinogen levels. Overall, these findings suggest that that fibrinogen contributes to microglia-mediated inflammation in the diabetic retina. Supported by R01 EY029913

Soluble and membrane-bound isoforms of fractalkine differentially regulate microglia activation and vascular damage in the diabetic retina

Abstract Diabetic retinopathy (DR) is the leading cause of blindness worldwide due to neuronal loss, microgliosis, and vascular damage. Inflammation caused by microglia exacerbates retinal damage, resulting in glial and neuronal cell dysfunction. Microglial-neuronal crosstalk mediated by CX3CR1/FKN signaling regulates microglial responses. CX3CR1 polymorphic variants present in 25% of the population decrease FKN binding affinity to CX3CR1, and their role in microglia function in the retina during diabetes is unknown. FKN exists as a membrane-bound (mFKN) adhesion molecule. When cleaved by proteases, the soluble (sFKN) form exerts chemoattractant properties. Previous studies show that disruption of CX3CR1/FKN signaling worsens retinal pathology and can be rescued by administration of recombinant FKN. Mechanisms by which mFKN and sFKN regulate retinal function are still unknown. We hypothesize that during diabetes, the over-expression of sFKN using recombinant adeno-associated viruses (rAAVs) will prevent vascular and neuronal damage, and improve visual function. To test this hypothesis, rAAVs expressing mFKN or sFKN were delivered to FKN-KO mouse retinas. We validated the expression of FKN levels in retinal protein extracts in mice that received rAAVs expressing mFKN or sFKN. Our findings revealed that rAAV-sFKN minimizes microglial activation, reduces fibrinogen deposition, and rescues neuronal loss, compared to rAAV-mFKN. rAAV-sFKN retinas of diabetic and non-diabetic mice improved visual function in a two-choice visual discrimination task. FKN appears to be neuroprotective, serving as an alternative therapeutic approach to minimize retinal pathology and improve visual function. Supported by NIH/NEI RO1 EY029913

Bullous lupus erythematosus with basement membrane deposits of IgD

Bullous lupus erythematosus is an uncommon blistering subepidermal autoimmune disease with characteristic immunopathological nosologic features. A 67-year-old female presented with the sudden appearance of blisters in the upper area of the right chest. Skin biopsies stained with H&amp;E favored the diagnosis of blistering lupus erythematous with a decrease in dermal sebaceous and eccrine glands. Direct immunofluorescence revealed deposits of IgG, complement C3, fibrinogen, IgM, and IgD in the epidermal corneal layer and the basement membrane zone. Reactivity to some dermal endothelial cell junctions and neural receptors was also noted. Also, complement C4 was positive against upper and middle dermal thin fibers. Complement D2 was positive around some enlarged dermal vessels, colocalizing with factor XIIIa. Our case highlights the complex and previously unreported immunologic response features associated with bullous lupus erythematosus.