Marker CD68 Research Articles

4-aminopyridine attenuates inflammation and apoptosis and increases angiogenesis to promote skin regeneration following a burn injury in mice

Severe thermal skin burns are complicated by inflammation and apoptosis, which delays wound healing and contributes to significant morbidity. Diverse treatments demonstrate limited success in mitigating these processes to accelerate healing. Agents that alter cell behavior to improve healing would alter treatment paradigms. We repurposed 4-aminopyridine (4-AP), a drug approved by the US FDA for multiple sclerosis, to treat severe burns in mice (10-week-old C57BL/6 J male mice weighing 25 ± 3 g). We found that 4-AP, in the early stages of burn healing, significantly reduced the expression of pro-inflammatory cytokines IL1β and TNFα while increasing the expression of anti-inflammatory markers CD206, ARG-1, and IL10. We demonstrated increased intracellular calcium effects of 4-AP through Orai1-pSTAT6 signaling, where 4-AP significantly mitigated inflammatory effects by promoting M2 macrophage differentiation in in-vitro macrophages and post-skin burn tissues. 4-AP attenuated apoptosis, with decreases in apoptotic markers BAX, caspase-9, and caspase-3 and increases in anti-apoptotic markers BCL2 and BCL-XL. Furthermore, 4-AP promoted angiogenesis through increases in the expression of CD31, VEGF, and eNOS. Together, these likely contributed to accelerated burn wound closure, as demonstrated in increased keratinocyte proliferation (K14) and differentiation (K10) markers. In the later stages of burn healing, 4-AP increased TGFβ and FGF levels, which are known to mark the transformation of fibroblasts to myofibroblasts. This was further demonstrated by an increased expression of α-SMA and vimentin, as well as higher levels of collagen I and III, MMP 3, and 9 in mice treated with 4-AP. Our findings support the idea that 4-AP may have a novel, clinically relevant therapeutic use in promoting burn wound healing.

Coumarin-chalcone derivatives as dual NLRP1 and NLRP3 inflammasome inhibitors targeting oxidative stress and inflammation in neurotoxin-induced HMC3 and BE(2)-M17 cell models of Parkinson's disease.

In Parkinson's disease (PD) brains, microglia are activated to release inflammatory factors to induce the production of reactive oxygen species (ROS) in neuron, and vice versa. Moreover, neuroinflammation and its synergistic interaction with oxidative stress contribute to the pathogenesis of PD. In this study, we investigated whether in-house synthetic coumarin-chalcone derivatives protect human microglia HMC3 and neuroblastoma BE(2)-M17 cells against 1-methyl-4-phenyl pyridinium (MPP+)-induced neuroinflammation and associated neuronal damage. Treatment with MPP+ decreased cell viability as well as increased the release of inflammatory mediators including cytokines and nitric oxide in culture medium, and enhanced expression of microglial activation markers CD68 and MHCII in HMC3 cells. The protein levels of NLRP3, CASP1, iNOS, IL-1β, IL-6, and TNF-α were also increased in MPP+-stimulated HMC3 cells. Among the four tested compounds, LM-016, LM-021, and LM-036 at 10 μM counteracted the inflammatory action of MPP+ in HMC3 cells. In addition, LM-021 and LM-036 increased cell viability, reduced lactate dehydrogenase release, ameliorated cellular ROS production, decreased caspase-1, caspase-3 and caspase-6 activities, and promoted neurite outgrowth in MPP+-treated BE(2)-M17 cells. These protective effects were mediated by down-regulating inflammatory NLRP1, IL-1β, IL-6, and TNF-α, as well as up-regulating antioxidative NRF2, NQO1, GCLC, and PGC-1α, and neuroprotective CREB, BDNF, and BCL2. The study results strengthen the involvement of neuroinflammation and oxidative stress in PD pathogenic mechanisms, and indicate the potential use of LM-021 and LM-036 as dual inflammasome inhibitors in treating both NLRP1- and NLRP3-associated PD.

YKL40/Integrin β4 Axis Induced by the Interaction between Cancer Cells and Tumor-Associated Macrophages Is Involved in the Progression of High-Grade Serous Ovarian Carcinoma.

Macrophages in the tumor microenvironment, termed tumor-associated macrophages (TAMs), promote the progression of various cancer types. However, many mechanisms related to tumor-stromal interactions in epithelial ovarian cancer (EOC) progression remain unclear. High-grade serous ovarian carcinoma (HGSOC) is the most malignant EOC subtype. Herein, immunohistochemistry was performed on 65 HGSOC tissue samples, revealing that patients with a higher infiltration of CD68+, CD163+, and CD204+ macrophages had a poorer prognosis. We subsequently established an indirect co-culture system between macrophages and EOC cells, including HGSOC cells. The co-cultured macrophages showed increased expression of the TAM markers CD163 and CD204, and the co-cultured EOC cells exhibited enhanced proliferation, migration, and invasion. Cytokine array analysis revealed higher YKL40 secretion in the indirect co-culture system. The addition of YKL40 increased proliferation, migration, and invasion via extracellular signal-regulated kinase (Erk) signaling in EOC cells. The knockdown of integrin β4, one of the YKL40 receptors, suppressed YKL40-induced proliferation, migration, and invasion, as well as Erk phosphorylation in some EOC cells. Database analysis showed that high-level expression of YKL40 and integrin β4 correlated with a poor prognosis in patients with serous ovarian carcinoma. Therefore, the YKL40/integrin β4 axis may play a role in ovarian cancer progression.

Analysis of CD3, CD68, CD163 and CK-19 expression in thymuses of neonatal children during infectious diseases

Objective: to identify the features of expression of immunohistochemical markers CD3, CD68, CD163 and CK-19 in thymus cells of neonatal children with enlarged thymus who died from infectious diseases. Material and methods. Autopsy material of children of early and late neonatal period (n=33) who died in the hospitals of Saratov city served as the material of the study. The causes of death of children were pneumonia (n=17), sepsis (n=16). Morphologic material was divided into 2 groups: Group 1 (comparison) — children whose thymus gland mass corresponded to the age norm (n=19); Group 2 (study group) — children whose thymus mass exceeded the age norm (n=14). The expression of the following markers was evaluated in the study: CD3, CD68, CD163 and CK-19. Results. As a result of the study, it was found that with increasing thymus mass in its cortical substance the proportion of CD3+ cells increase 2.7 times (p=0.009), the proportion of CD68+ cells increase almost threefold (p=0.009) CD163+ cells decreases by 10% (p=0.005), and CK-19 positive cells do not form a network. Conclusion. Increased thymus mass in children of early neonatal period with infectious diseases is accompanied by disturbances in the processes of migration and differentiation of lymphocytes.

Microglial TREM2 promotes phagocytic clearance of damaged neurons after status epilepticus

In the central nervous system, triggering receptor expressed on myeloid cells 2 (TREM2) is exclusively expressed by microglia and is critical for microglial proliferation, migration, and phagocytosis. Microglial TREM2 plays an important role in neurodegenerative diseases, such as Alzheimer’s disease and amyotrophic lateral sclerosis. However, little is known about how TREM2 affects microglial function within epileptogenesis. To investigate this, we utilized male TREM2 knockout (KO) mice within the intra-amygdala kainic acid seizure model. Electroencephalographic analysis, immunocytochemistry, and RNA sequencing revealed that TREM2 deficiency significantly promoted seizure-induced pathology. We found that TREM2 KO increased both the severity of acute status epilepticus and the number of spontaneous recurrent seizures characteristic of chronic focal epilepsy. Phagocytic clearance of damaged neurons by microglia was also impaired by TREM2 KO and reduced phagocytic activity correlated with increased spontaneous seizures. Analysis of human tissue from patients who underwent surgical resection for drug resistant temporal lobe epilepsy also showed a negative correlation between expression of the microglial phagocytic marker CD68 and focal to bilateral tonic-clonic generalized seizure history. These results indicate that microglial TREM2 and phagocytic activity are important to epileptogenic pathology.

Immune cells and tryptophan metabolism in the joint capsule tissue in rheumatoid arthritis

To the present day, many links in the pathogenesis of rheumatoid arthritis remain unclear, which leads to unsatisfactory results in its therapy.The aim. To study the cells involved in immune reactions and tryptophan metabolites in the joint capsule in rheumatoid arthritis.Materials and methods. The experiments were carried out on 40 Wistar rats. Rheumatoid arthritis was induced by intraperitoneal injection of a solution of type 2 collagen (Chondrex Inc., USA) in incomplete Freund’s adjuvant. On the days 7, 14 and 21, the content of tryptophan, kynurenine, 3-hydrokenurinine, L-5-hydrotryptophan in the joint capsule was determined using high-performance liquid chromatography. Cells with CD3, CD20 and CD68 in joint tissues were studied at the same time using the streptavidin-biotin-peroxidase method. We used enzyme-linked immunosorbent method to determine antibodies to citrulline-containing peptide. Statistical analysis was performed using the Jamovi, version 2.3 software.Results. The content of cells carrying CD3, CD20 and CD68 markers in the joint was high in experimental rheumatoid arthritis. In joint tissues, the content of tryptophan metabolites along the kynurenine pathway also increases and the concentration of metabolites along the serotonin pathway decreases. Direct positive correlations of cells carrying CD3, CD20 and CD68 differential clusters with the content of tryptophan metabolites along the kynurenine pathway and negative correlations with metabolites of the serotonin pathway were established.Conclusions. Cells carrying CD3, CD20 and CD68 markers and tryptophan metabolites – kynurenine and L-5-hydrotryptophan – play an important role in the pathogenesis of rheumatoid arthritis.

Facilitating cholangiocarcinoma inhibition by targeting CD47

Immune evasion is one of the mechanisms by which cancer cells acquire immunity during cancer development and progression. One of these is the increased expression of cluster of differentiation 47 (CD47), a transmembrane glycoprotein that protects cells from phagocytic elimination. The interaction between CD47 and signal regulatory protein alpha (SIRPα) on macrophages alleviates the phagocytic signal. The present group previously reported high CD47 expression in cholangiocarcinoma (CCA), a major health problem in Thailand and East Asia, and that blocking CD47 using anti-CD47 antibodies promoted the removal of CCA. However, the mechanism through which CD47 inhibition attenuates CCA growth remains unclear. This study explored the clinical significance of targeting CD47 in CCA. Expression levels of CD47 and the macrophage marker CD68 were determined in CCA tissues by immunohistochemistry and correlated with clinical parameters. The role of CD47 in CCA cells was established using CD47-deficient KKU-213A CCA clones in vitro and in vivo. The results showed that CD47 was highly expressed in CCA tissues and significantly correlated with lymph node metastasis (P = 0.038). Moderate-to-dense CD68-positive infiltrating cells in CCA tissues were significantly associated with shorter survival of patients (P = 0.019) and were an independent prognostic factor of CCA patients as determined by the Cox proportional hazard model (hazard ratio, 2.040; 95 % confidence interval, 1.109–3.752; P = 0.022). Three CD47-deficient KKU-213A clones (#19, #23, and #28) were generated. The elimination of CD47 did not affect cell proliferation but increased monocyte-derived macrophage-mediated phagocytosis in vitro. Decreased tumor weights and volumes were observed in mice injected with CD47-deficient CCA clones. This revealed a significant role for CD47 in CCA, with a focus on protecting cancer cells from macrophage phagocytosis.

Comparative immunohistochemical expression of Beta catenin and CD163 between dysplastic / non-dysplastic oral lichen planus and lichenoid lesions (EX-VIVO STUDY)

BackgroundOral lichen planus is a well-known chronic inflammatory mucocutaneous disorder, which has clinical and histological presentation that mimics oral lichenoid reaction. According to the fifth edition of WHO, both conditions are considered as oral potentially malignant disorders. Recent studies on oral potential disorders documented deregulation of some signaling molecules related to the Wnt/β-catenin pathway. Therefore this study aimed to compare the immune expression of β-catenin & CD163 in dysplastic /non-dysplastic cases of Oral lichen planus & oral lichenoid lesion. In addition, a statistical correlation between both immune markers was done regardless of the type of the study group.MethodsFour study groups were designated as 2 groups of Oral lichen planus (one dysplastic & one non –dysplastic) and the other 2 groups were oral lichenoid lesions (one dysplastic & one non –dysplastic). Ten cases in each group were collected and investigated by immunohistochemistry. The area percent of beta catenin and also counting of m2 macrophages expressing + CD163 marker was calculated in the study groups.ResultsThe Statistical analysis highlighted a statistically significant difference between the studied groups. Moreover, Pearson correlation test reported a significant moderate positive correlation between beta catenin & CD163 expression in the studied cases.ConclusionOur findings supported new perceptions of the mechanism by which tumor associated macrophage specific β-catenin signaling promotes the aggressive behavior of oral potential malignant disorders.Clinical relevanceEvidence of the relationship between beta catenin and M2 macrophages (+ CD163) may enhance the development of macrophage-based strategies for treatment and improve the prognosis of such cases.

Distinct activation of M1 and M2 macrophages in the primary pterygium lymphangiogenesis

The precise role and innate immunological mechanisms underlying lymphangiogenesis in pterygium remain unclear. This study aimed to investigate the presence of M1 and M2 macrophages and their correlation with pro-lymphangiogenic activation and lymphatic endothelial expression in human pterygium stromal tissues. We analyzed human pterygium and subject-matched normal conjunctival tissues for the expression of these factors and conducted in vitro experiments to assess interactions between macrophages and pterygium fibroblasts. Myeloid and M1 macrophage markers were upregulated in pterygium. M1 macrophages were associated with the upregulation of pro-lymphangiogenic vascular endothelial growth factor C (Vegfc) in pterygium tissues and induced inflammatory signals in pterygium fibroblasts. In contrast, lymphatic vessel endothelial hyaluronan receptor 1 (Lyve1) expression was associated with M2 markers but not with M1 markers. Notably, the clinical severity of pterygium was inversely correlated with the expression of the M2 marker Cd163. These findings suggest that M1 and M2 macrophages play distinct roles in the pathogenesis of pterygium, with M1 macrophages enhancing lymphangiogenic stimulation and inflammatory responses, while M2 macrophages are associated with Lyve1 expression and reduced severity of pterygium. Understanding these mechanisms may advance our current understanding of lymphatic biology in pterygium.

Features of beta cell differentiation during the development of type 2 diabetes mellitus

Type 2 diabetes mellitus is characterized by a mild inflammatory reaction in the pancreas, which affects the structure and function of the pancreatic islets: the number of β-cells decreases and the number of α-cells increases. The work examined the features of β-cell differentiation in the development of experimental type 2 diabetes mellitus and while reducing the inflammatory process. Biochemical, histological methods, enzyme-linked immunosorbent assay, immunohistochemical methods were used using primary antibodies to insulin, glucagon, proliferation marker Ki-67 and secondary antibodies labeled with fluorescent dyes. Streptozotocin and nicotinamide were used to model type 2 diabetes mellitus, and the sodium salt of 5-amino-2,3-dihydrophthalazine-1,4-dione was used to reduce the inflammatory response. Previous studies have shown that it changes the macrophage phenotype from proinflammatory M1 to anti-inflammatory M2. In type 2 diabetes mellitus, against the background of a decrease in the number of macrophages with the CD163 marker and the concentration of the cytokine TGF-β1, which have an anti-inflammatory effect, in the pancreatic islets, a decrease in the number of β-cells and their functional activity was observed, while the content of α-cells synthesizing glucagon increased. After administration of the sodium salt of 5-amino-2,3-dihydrophthalazine-1,4-dione, the opposite picture was observed in the pancreatic islets: against the background of an increase in the number of CD163+ macrophages and the content of TGF-β1, the number of β cells increased and the number of α cells decreased-cells. The increase in the number of insulin-synthesizing cells was not accompanied by their mitotic activity. It is likely that a decrease in the number of CD163+ macrophages and the level of the antiinflammatory cytokine TGF-β1 in the islets are factors contributing to changes in the cell microenvironment and, as a consequence, the differentiation of β-cells into α-cells. On the contrary, an increase in the number of CD163+ macrophages and TGF-β1 against the background of administration of the sodium salt of 5-amino-2,3-dihydrophthalazine-1,4-dione presumably promotes reverse differentiation of α-cells into β-cells and restoration of insulin synthesis pancreas. Targeted effects on the microenvironment of cells in the pancreatic islet in type 2 diabetes mellitus may be a new approach to treating the disease.

Immunological Tumor Microenvironment of Solitary Fibrous Tumors-Associating Immune Infiltrate with Variables of Prognostic Significance.

Solitary fibrous tumors (SFTs) are morphologically heterogeneous tumors characterized by the NAB2::STAT6 gene fusion. Clinical outcomes may vary widely, and while most cases have favorable outcomes, some can progress to aggressive disease, manifesting as recurrence and metastasis, and ultimately resulting in patient death. Herein, we analyze the immunological tumor microenvironment (ITME) of SFTs, aiming to determine its prognostic value and correlation with established risk stratification systems (RSSs). A retrospective observational multicenter study of 52 fusion-confirmed SFTs with clinical follow-up data. Immunohistochemical analysis including CD163, CD68, CD3, CD8, CD20, PDL-1, PD-1, and LAG1 were evaluated in tissue microarrays, using an analog scale with scores ranging from 0 to 3 (0 = ≤9, 1 = 10-49, 2 = 50-99, and 3 = >100 positive cells per 10 high-power fields). The expression of these markers was correlated with clinical outcomes, morphological characteristics previously evaluated in whole slide tissue sections (hypercellularity/hypocellularity, round-oval or spindle dominant constituent cell (DCC) morphology, and necrosis), Ki67, overall survival, and RSS. Only one of the fifty-two cases studied showed progression. In the multivariate analysis, neither the presence nor absence of immune cells (B-lymphocytes, T-lymphocytes, and macrophages) showed any association with the assessed RSSs (Demicco, Sugita, G-score, and Huang). Interestingly, the case that showed progression had high immune infiltrate with expression of CD68, CD163, CD8, and CD20 markers (score of 3). Round-oval cell morphology was associated with the presence of higher levels of CD163 macrophages. Lastly, the scant presence of CD20+ lymphocytes correlated with less necrosis, and cases with higher PDL-1 expression correlated with increased Ki67 values. All cases were negative for LAG-1 and PD-1. SFT ITME components correlated with independent variables with prognostic significance. Nevertheless, ITME did not correlate with RSS scores.

Differences in human and commercial hybrid pig platelet activation induced by borosilicate glass beads in a modified chandler loop-system.

The pig (Sus scrofa) is the most widely used large animal model in Europe, with cardiovascular research being one of the main areas of application. Adequate refinement of interventional studies in this field, meeting the requirements of Russell and Burch's 3 R concept, can only be performed if blood-contacting medical devices are hemocompatible. Because most medical devices for cardiovascular interventional procedures are developed for humans, they are tested only for compatibility with human blood. The aim of this study was therefore to determine whether there are differences in behavior of human and porcine platelets from commercial hybrid pigs when they come into contact with borosilicate glass, which was used as an exemplary thrombogenic material. For this purpose, changes in platelet count, platelet volume and platelet expression of the activation markers CD61, CD62P and CD63 were measured using a modified chandler loop-system simulating the fluidic effects of the bloodflow. Commercial hybrid pig and human platelets showed significant adhesions to borosilicate glass but the commercial hybrid pigs platelets showed a significantly higher tendency to adhere to borosilicate glass. In contrast to human platelets the platelets of commercial hybrid pigs showed significant activation after 4 to 8 minutes exposure to borosilicate glass and there were differences among the ratios of surface and activation markers in between the platelets of both species.

High-fat and High-sucrose Diet-induced Hypothalamic Inflammation Shows Sex Specific Features in Mice.

Hypothalamic inflammation underlies diet-induced obesity and diabetes in rodent models. While diet normalization largely allows for recovery from metabolic impairment, it remains unknown whether long-term hypothalamic inflammation induced by obesogenic diets is a reversible process. In this study, we aimed at determining sex specificity of hypothalamic neuroinflammation and gliosis in mice fed a fat- and sugar-rich diet, and their reversibility upon diet normalization. Mice were fed a 60%-fat diet complemented by a 20% sucrose drink (HFHSD) for 3 days or 24 weeks, followed by a third group that had their diet normalized for the last 8 weeks of the study (reverse diet group, RevD). We determined the expression of pro- and anti-inflammatory cytokines, and of the inflammatory cell markers IBA1, CD68, GFAP and EMR1 in the hypothalamus, and analyzed morphology of microglia (IBA-1+ cells) and astrocytes (GFAP+ cells) in the arcuate nucleus. After 3 days of HFHSD feeding, male mice showed over-expression of IL-13, IL-18, IFN-γ, CD68 and EMR1 and reduced expression of IL-10, while females showed increased IL-6 and IBA1 and reduced IL-13, compared to controls. After 24 weeks of HFHSD exposure, male mice showed a general depression in the expression of cytokines, with prominent reduction of TNF-α, IL-6 and IL-13, but increased TGF-β, while female mice showed over-expression of IFN-γ and IL-18. Furthermore, both female and male mice showed some degree of gliosis after HFHSD feeding for 24 weeks. In mice of both sexes, diet normalization after prolonged HFHSD feeding resulted in partial neuroinflammation recovery in the hypothalamus, but gliosis was only recovered in females. In sum, HFHSD-fed mice display sex-specific inflammatory processes in the hypothalamus that are not fully reversible after diet normalization.

Monocyte and macrophage profiles in patients with inherited long-chain fatty acid oxidation disorders

Patients with inherited disorders of the long-chain fatty acid oxidation (lcFAO) machinery present with a heterogeneous profile of disease manifestations and aggravation of symptoms is often triggered by inflammatory activation. Monocytes and macrophages are innate immune cells that play a major role in the onset and resolution of inflammation. These cells undergo metabolic rewiring upon activation including the regulation of the FAO rate. The rewiring of FAO and the effect of lcFAO disorders (lcFAOD) on human monocyte and macrophage phenotype and function remain largely unknown. Here, we performed extensive phenotyping of circulating monocytes and analyzed plasma cytokine levels in 11 lcFAOD patients and 11 matched control subjects. In patients with lcFAOD, we observed induced plasma levels of the inflammatory cytokines IL-1β and IL-6, and enhanced CD206 and CD62L surface marker expression in circulating monocyte subsets. To mimic the most common lcFAOD very-long-chain acyl-CoA dehydrogenase disorder (VLCADD), we used siRNA-mediated knockdown of the ACADVL gene (encoding VLCAD) in macrophages derived from healthy volunteers. Hereby, we found that siVLCAD affected IL-4-induced alternative macrophage activation while leaving LPS responses and cellular metabolism intact. In the same line, monocyte-derived macrophages from lcFAOD patients had elevated levels of the IL-4-induced alternative macrophage markers CD206 and CD200R. Still, they did not show major metabolic defects or changes in the LPS-induced inflammatory response. Our results indicate that monocytes and macrophages from lcFAOD patients present no major inflammatory or metabolic differences and show that IL-4-induced surface markers are intertwined with lcFAO in human macrophages.

Expression of antigen-presenting cells in lung of postmortem SARS-CoV-2 cases.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a deadly pulmonary disease with impaired immunological response that causes significant tissue damage and organ failure. Postmortem examination of the lung is a useful tool for understanding the immunopathogenesis of this virus. Lung autopsy samples from seven dead SARS-CoV-2 patients were obtained and evaluated using hematoxylin and eosin stain to analyze the histopathological changes in those samples, on the other hand, Immunohistochemical (IHC) staining was used for detection of CD21, CD1a, CR1 (CD35), CD68, Myeloperoxidase (MPO), CD15, CD56, CD3, CD20, CD4, and CD8 cells markers. Histopathological examination revealed diffuse alveolar damage with extensive parenchymal architecture distortion, intravascular fibrin clot, deposition of collagen fibers, vascular congestions and blood vessels containing thrombi, pneumocyte type II with inflammatory cell infiltration. The IHC staining for the innate immune cells such as antigen-presenting cells (APCs) including dendritic cells, Macrophages, and neutrophils showed a strong positive staining, while CD56 Natural killer (NK) cells showed negative staining. On the other hand, the specific immune cells including; CD20 B cells, CD3 T cells, and CD4 helper T cells, showed positive staining while CD8 Cytotoxic T cells showed negative staining. The lung autopsy samples from patients with COVID-19 confirmed the presence of APCs through the positive staining of CD21, CD1a, CD35, CD68, MPO, and CD15 expressed the virus recognition, proinflammatory cytokine production, and adaptive immune cells activation through CD3, CD4, and CD20 positive staining and the role of APCs in the severity of pulmonary infection and pathogenesis of SARS-CoV-2 infection however the absence of the CD56 NK and CD8 cytotoxic T explains the worse infection status for the patients.

Electrospun Fiber Surface Roughness Modulates Human Monocyte-Derived Macrophage Phenotype.

Injuries to fibrous connective tissues have very little capacity for self-renewal and exhibit poor healing after injury. Phenotypic shifts in macrophages play a vital role in mediating the healing response, creating an opportunity to design immunomodulatory biomaterials which control macrophage polarization and promote regeneration. In this study, electrospun poly(-caprolactone) fibers with increasing surface roughness (SR) were produced by increasing relative humidity and inducing vapor-induced phase separation during the electrospinning process. The impact of surface roughness on macrophage phenotype was assessed using human monocyte-derived macrophages in vitro and in vivo using B6.Cg-Tg(Csf1r-EGFP)1Hume/J (MacGreen) mice. In vitro experiments showed that macrophages cultured on mesh with increasing SR exhibited decreased release of both pro- and anti-inflammatory cytokines potentially driven by increased protein adsorption and biophysical impacts on the cells. Further, increasing SR led to an increase in the expression of the pro-regenerative cell surface marker CD206 relative to the pro-inflammatory marker CD80. Mesh with increasing SR were implanted subcutaneously in MacGreen mice, again showing an increase in the ratio of cells expressing CD206 to those expressing CD80 visualized by immunofluorescence. SR on implanted biomaterials is sufficient to drive macrophage polarization, demonstrating a simple feature to include in biomaterial design to control innate immunity.

Decreased sialylation elicits complement-related microglia response and bipolar cell loss in the mouse retina.

Sialylation plays an important role in self-recognition, as well as keeping the complement and innate immune systems in check. It is unclear whether the reduced sialylation seen during aging and in mice heterozygous for the null mutant of UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (Gne+/-), an essential enzyme for sialic acid biosynthesis, contributes to retinal inflammation and degeneration. We found a reduction of polysialic acid and trisialic acid expression in several retinal layers in Gne+/- mice at 9 months of age compared to Gne+/+ wildtype (WT) mice, which was associated with a higher microglial expression of the lysosomal marker CD68. Furthermore, the total number of rod bipolar cells was reduced in 12 months old Gne+/- mice in comparison to WT mice, demonstrating loss of these retinal interneurons. Transcriptome analysis showed up-regulation of complement, inflammation, and apoptosis-related pathways in the retinas of Gne+/- mice. Particularly, increased gene transcript levels of the complement factors C3 and C4 and the pro-inflammatory cytokine Il-1β were observed by semi-quantitative real-time polymerase chain reaction (sqRT-PCR) in 9 months old Gne+/- mice compared to WT mice. The increased expression of CD68, loss of rod bipolar cells, and increased gene transcription of complement factor C4, were all prevented after crossing Gne+/- mice with complement factor C3-deficient animals. In conclusion, our data show that retinal hyposialylation in 9 and 12 months old Gne+/- mice was associated with complement-related inflammation and lysosomal microglia response, as well as rod bipolar cells loss, which was absent after genetic deletion of complement factor C3.

Cytologic diagnosis and differential diagnosis of histiocytic signet ring cells in effusion specimens.

Benign histiocytic proliferation in effusion specimens can be found in a variety of diseases such as rheumatoid arthritis, systemic lupus erythematosus, microorganism infections, trauma, reactive eosinophilic pleuritis, and others. In addition, nodular histiocytic/mesothelial hyperplasia is another well-recognized rare cause. The previous studies have shown that proliferative histiocytes have raisinoid nuclei and abundant eosinophilic granular cytoplasm and can be confused with malignant lesions, especially metastatic carcinomas. In this study, we evaluated the cytomorphology of benign histiocytes, discussed the diagnosis and differential diagnosis, and the clinical significance of histiocytic signet ring cells in effusion cytology. Seven hundred and fifty-five benign effusion cases (433 pleural effusions and 322 abdominal fluids) were found over 1 year. Among benign cases, 35 cases (28 pleural effusions and seven abdominal fluids) were included with findings of dominantly histiocytic signet ring cell morphology as well as immunohistochemical (IHC) stains. The clinical findings were also correlated. In contrast to the well-documented cytomorphology of raisinoid nuclei and eosinophilic cytoplasm of proliferative histiocytes in previous studies, we find that these cells predominately presented as signet ring cell morphology with clear cytoplasm. The most characteristic findings of benign histiocytes in pleural effusions are: (1) cells are arranged in sheets and/or scattered individual cells, but no two- or three-dimensional cell clusters; (2) cells are intermediate in size and with normal N/C ratio; (3) cells have eccentric located nuclei and abundant clear cytoplasm, giving signet ring cell appearance; (4) nuclei have fine granular chromatin pattern, no hyperchromia or coarse chromatin pattern, no nuclear atypia; and (5) immunohistochemical (IHC) stains demonstrate a strongly positivity for macrophage-histiocyte lineage marker CD68, but negativity for epithelial markers and mesothelial markers. Clinically, these patients do not demonstrate nodularity or lesions in the mesothelial lining of serous cavities. Our study provides a detailed characterization of benign histiocytic signet ring cells in effusion cytology. The differential diagnosis of histiocytic signet ring cells is broad. The most important differential diagnoses are metastatic adenocarcinoma and epithelioid signet ring cell mesothelioma. The accurate diagnosis is critical for the appropriate clinical management of the patient. Cytopathologists should be aware of the diagnostic pitfalls of benign histiocytic signet ring cells in effusion samples in daily practice.

Study of histopathological and ultrastructural changes in the lungs of COVID-19 patients

BackgroundCOVID 19 infection is a multi-systemic disease with the lungs bearing the maximum brunt. Very few autopsy studies have been done on the deceased patients. The present study aimed to study the clinical spectrum and lab parameters of COVID-19 patients along with the morphological spectrum of the lung changes in these patients by histology, Immunohistochemistry and Electron microscopy. We also compared the Clinical severity and Lab parameters with the histopathological phase of the lung involvement. MethodsWe conducted a cross sectional observational study between Jun 2021 to Dec 2022 where in needle necropsy of lung tissue of COVID 19 confirmed fatal cases were studied by histopathology, immunohistochemistry (using CD3, CD4, CD8, CD19, CD20, CD68 and Pan CK markers) and Electron microscopy. Various hematological, histopathological and ultrastructural parameters were studied. The results were analyzed using SPSS 25.0 software. ResultsA total of 24 cases were studied. The mean age was 65.9 yrs, male: female ratio was 2:1. Five had moderately severe COVID while 19 had severe COVID infection. Diffuse alveolar damage (DAD) was seen in 83% of all the cases. On the basis of clinical severity and histopathological staging, broadly two histopathological groups were made (Proliferative and Organizing). Difference between TLC, N/L ratio and L/Platelet ratio in two histopathological groups was assessed using unpaired t test, however no significant difference was noted. We did not find any correlation between clinical severity and histopathological groups though severe cases of COVID-19 were found to have a shorter time between admission to the hospital and death. All the biopsies were subjected to electron microscopy and in two of the cases we could demonstrate corona virus particles. ConclusionOur study has shown that severe cases of COVID 19 are associated with a shorter time between admission to hospital and death. While the histopathology of the lung showed diffuse alveolar damage as the most common finding; the Transmission Electron Microscopy (TEM) played an important role in characterizing the ultrastructure of these cells and demonstrating corona virus particles.

Abstract P335: An innate immune component in hypertension-induced cardiac dysfunction Christoph Mora, Katherine Deck, Yunmeng Liu, Lance Benson, Tonya Rafferty, & Shengyu Mu

Hypertension affects nearly half of American adults, inevitably leading to cardiac dysfunction and heart failure. Cardiac fibrosis is a major factor contributing to cardiac dysfunction during hypertension progression. However, the mechanisms involved in cardio-fibrogenesis remain to be elucidated. In the past decade, studies revealed that macrophages could differentiate into professional fibrotic cells, myofibroblasts, through a process termed macrophage to myofibroblast transition (MMT), helping maintain the integrity of major organs, such as the kidney. However, it is unknown whether MMT contributes to fibrotic remodeling in hypertensive hearts. Here, we aim to identify this phenomenon in the hearts of hypertensive animals and determine the role it plays in the pathological progression from hypertension to cardiac diastolic dysfunction. In this study we adopt the classic DOCA + Salt model of hypertension and utilized cardiac ultrasound and direct left ventricular (LV) pressure catheterization to gauge diastolic function. Heart sections from hypertensive and sham mice were stained with Masson’s trichrome to assess the extent of cardiac fibrosis. Furthermore, flow cytometry was utilized to identify MMT cells, which express both CD68 (monocytes) and α-SMA (myofibroblast) markers. These methods gave insight into the role that MMT plays in the degradation of heart function during hypertension. Direct left ventricle pressure catheter revealed that DOCA + salt mice exhibited impaired diastolic function. This result is supported by cardiac ultrasound showing that the compliance of the heart had significantly decreased, as evidenced by the lowering of the efferent/atrial (E/A) ratio and deceleration time (DcT). In addition to this evidence of mechanical cardiac degradation, leukocytes isolated from the heart and stained with macrophage and myofibroblast markers revealed a significant increase in CD68+ & αSMA+ cells—a result reflected by increased fibrotic remodeling via Masson’s trichrome stain, in the hypertensive animals. This study demonstrated an onset of diastolic dysfunction in the heart of DOCA + salt hypertensive mice. Moreover, we found a positive association between MMT cells and fibrosis in the hearts of hypertensive animals. Future studies will aim to parse out both the gravity of MMT in hypertensive heart dysfunction and the mechanism by which macrophages undergo this transition to find new targets against this debilitating disease.