Macrophage polarisation: an immunohistochemical approach for identifying M1 and M2 macrophages

Natural product/diet-based regulation of macrophage polarization: Implications in treatment of inflammatory-related diseases and cancer

Macrophages are phagocytic cells with important physiological functions, including the digestion of cellular debris, foreign substances, and microbes, as well as tissue development and homeostasis. The tumor microenvironment (TME) shapes the aggressiveness of cancer, and the biological and cellular interactions in this complicated space can determine carcinogenesis. TME can determine the progression, biological behavior, and therapy resistance of human cancers. The macrophages are among the most abundant cells in the TME, and their functions and secretions can determine tumor progression. The education of macrophages to M2 polarization can accelerate cancer progression, and therefore, the re-education and reprogramming of these cells is promising. Moreover, macrophages can cause inflammation in aggravating pathological events, including cardiovascular diseases, diabetes, and neurological disorders. The natural products are pleiotropic and broad-spectrum functional compounds that have been deployed as ideal alternatives to conventional drugs in the treatment of cancer. The biological and cellular interactions in the TME can be regulated by natural products, and for this purpose, they enhance the M1 polarization of macrophages, and in addition to inhibiting proliferation and invasion, they impair the chemoresistance. Moreover, since macrophages and changes in the molecular pathways in these cells can cause inflammation, the natural products impair the pro-inflammatory function of macrophages to prevent the pathogenesis and progression of diseases. Even a reduction in macrophage-mediated inflammation can prevent organ fibrosis. Therefore, natural product-mediated macrophage targeting can alleviate both cancerous and non-cancerous diseases.

Characterization and modulation of the pro-inflammatory effects of immune cells in the canine intervertebral disk

Background

Intervertebral disk (IVD) degeneration affects both humans and canines and is a major cause of low back pain (LBP). Mast cell (MC) and macrophage (MØ) infiltration has been identified in the pathogenesis of IVD degeneration (IVDD) in the human and rodent model but remains understudied in the canine. MC degranulation in the IVD leads to a pro-inflammatory cascade and activates protease activated receptor 2 (PAR2) on IVD cells. The objectives of the present study are to: (1) highlight the pathophysiological changes observed in the degenerate canine IVD, (2) further characterize the inflammatory effect of MCs co-cultured with canine nucleus pulposus (NP) cells, (3) evaluate the effect of construct stiffness on NP and MCs, and (4) identify potential therapeutics to mitigate pathologic changes in the IVD microenvironment.

Methods

Canine IVD tissue was isolated from healthy autopsy research dogs (beagle) and pet dogs undergoing laminectomy for IVD herniation. Morphology, protein content, and inflammatory markers were assessed. NP cells isolated from healthy autopsy (Mongrel hounds) tissue were co-cultured with canine MCs within agarose constructs and treated with cromolyn sodium (CS) and PAR2 antagonist (PAR2A). Gene expression, sulfated glycosaminoglycan content, and stiffness of constructs were assessed.

Results

CD 31+ blood vessels, mast cell tryptase, and macrophage CD 163+ were increased in the degenerate surgical canine tissue compared to healthy autopsy. Pro-inflammatory genes were upregulated when canine NP cells were co-cultured with MCs and the stiffer microenvironment enhanced these effects. Treatment with CS and PAR2 inhibitors mediated key pro-inflammatory markers in canine NP cells.

Conclusion

There is increased MC, MØs, and vascular ingrowth in the degenerate canine IVD tissue, similar to observations in the clinical population with IVDD and LBP. MCs co-cultured with canine NP cells drive inflammation, and CS and PAR2A are potential therapeutics that may mitigate the pathophysiology of IVDD in vitro.

Neuroimmunomodulatory effect of Nitric Oxide on chronic wound healing after photodynamic therapy

Neuroimmunomodulation is the capacity of the nervous system to regulate immune processes. The existence of neurotransmitter receptors in immune cells enables this phenomenon to take place. Neuronal mediators possess the capacity to direct and control several occurrences during the wound healing process. Nitric oxide (NO) functions as a neuromodulator, playing a crucial role in the regulation of vascular tone and blood pressure with antimicrobial properties. Photodynamic therapy has been shown to augment the function of immune cells involved in the healing process of venous leg ulcers. Nitric oxide can be secreted into the extracellular environment by these cells. In lesions treated with PDT, the synthesis of iNOs (the enzyme that releases NO) increased, as demonstrated by the experimental results. Therefore the significance of PDT in enhancing the clinical condition of the lesion is thus highlighted.

Melatonin at repeated doses alleviates hyperglycemia-exacerbated cerebral ischemia-reperfusion injury at 72 h via anti-inflammation and anti-apoptosis

Objective

We aimed to investigate how hyperglycemia would exacerbate cerebral ischemia-reperfusion injury (CIRI) in a rat model of type 1 diabetes mellitus (T1DM) and explore the beneficial effects of multiple doses of melatonin in T1DM induced CIRI.

Method

The T1DM rat model was induced with streptozocin, and melatonin (10 mg/kg) was injected at 0.5 h before ischemia as well as at 24 and 48 h after reperfusion.

Results

When compared to normoglycemic (NG) rats, T1DM rats had hyperglycemia with weight loss before CIRI. Despite comparable degrees of ischemia and initial reperfusion, T1DM rats tended to have greater weight loss and had worse neurological deficits and larger infarct volume than NG rats up to 72 h after CIRI. Persistent activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway but not of apoptosis or calpains was a crucial factor in T1DM-mediated exacerbation of CIRI at 72 h. Despite lacking effects on baseline hyperglycemia, ischemia and initial reperfusion, melatonin at multiple doses lessened post-CIRI weight loss, neurological deficits and infarct volume in T1DM rats at 72 h. when compared to vehicle-treated T1DM rats with CIRI. Beneficial effects of melatonin treatment included decreased activation of NF-κB pathway, apoptosis and calpains, leading to reduced expression of inducible nitric oxide synthase and enhanced neuronal density.

Conclusion

Melatonin at multiple doses can alleviate T1DM-mediated exacerbation of CIRI at 72 h through anti-inflammation and anti-apoptosis.

Tumors of the nervous system and hearing loss: Beyond vestibular schwannomas

Hearing loss is a common side effect of many tumor treatments. However, hearing loss can also occur as a direct result of certain tumors of the nervous system, the most common of which are the vestibular schwannomas (VS). These tumors arise from Schwann cells of the vestibulocochlear nerve and their main cause is the loss of function of NF2, with 95 % of cases being sporadic and 5 % being part of the rare neurofibromatosis type 2 (NF2)-related Schwannomatosis. Genetic variations in NF2 do not fully explain the clinical heterogeneity of VS, and interactions between Schwann cells and their microenvironment appear to be critical for tumor development. Preclinical in vitro and in vivo models of VS are needed to develop prognostic biomarkers and targeted therapies. In addition to VS, other tumors can affect hearing. Meningiomas and other masses in the cerebellopontine angle can compress the vestibulocochlear nerve due to their anatomic proximity. Gliomas can disrupt several neurological functions, including hearing; in fact, glioblastoma multiforme, the most aggressive subtype, may exhibit early symptoms of auditory alterations. Besides, treatments for high-grade tumors, including chemotherapy or radiotherapy, as well as incomplete resections, can induce long-term auditory dysfunction. Because hearing loss can have an irreversible and dramatic impact on quality of life, it should be considered in the clinical management plan of patients with tumors, and monitored throughout the course of the disease.

Recent advances in potential targets for myocardial ischemia reperfusion injury: Role of macrophages

Myocardial ischemia-reperfusion injury (MIRI) is a complex process that occurs when blood flow is restored after myocardium infarction (MI) with exacerbated tissue damage. Macrophages, essential cell type of the immune response, play an important role in MIRI. Macrophage subpopulations, namely M1 and M2, are distinguished by distinct phenotypes and functions. In MIRI, macrophages infiltrate in infarcted area, shaping the inflammatory response and influencing tissue healing. Resident cardiac macrophages interact with monocyte-derived macrophages in MIRI, and influence injury progression. Key factors including chemokines, cytokines, and toll-like receptors modulate macrophage behavior in MIRI. This review aims to address recent findings on the classification and the roles of macrophages in the myocardium, spanning from MI to subsequent MIRI, and highlights various signaling pathways implicated in macrophage polarization underlining the complexity of MIRI. This article will shed light on developing advanced therapeutic strategies for MIRI management.

Innate Immunity Activation in Newly Diagnosed Ileocolonic Crohn's Disease: A Cohort Study

BACKGROUND

Recent studies showed that early surgery for Crohn's disease leads to a lower recurrence rate. However, the underlying mechanism is unknown.

OBJECTIVE

The study aims to analyze the innate immunity microenvironment in ileal mucosa according to the duration of Crohn's disease.

DESIGN

A prospective cohort study.

SETTINGS

Tertiary referral center for IBD surgery.

PATIENTS

A total of 88 consecutive patients with Crohn's disease undergoing ileocolonic resection were prospectively enrolled. Mucosal samples were obtained from both healthy and inflamed ileum. Data from a public data set were analyzed as an external validation cohort.

MAIN OUTCOME MEASURES

Neutrophil infiltration was evaluated by histological asessment and macrophage subpopulation was assessed by immunohistochemistry. Expressions of TLR2 , TLR4 , TLR5 , DEFB1 , DEFB4A , DEFB103 , DEFA5 , and DEFA6 were quantified by real-time quantitative polymerase chain reaction. Concentrations of BDNF, CCL-11, ICAM-1, IL-1A, IL-1β, IL-1RN, IL-12p40, IL-12p70, IL-15, IL-17A, IL-23A, MMP-3, CCL-3, KITLG, and VEGFA were determined with an immunometric assay.

RESULTS

Neutrophil infiltration is inversely correlated with disease duration. DEFB4A mRNA expression tended to be higher in late-stage Crohn's disease ( p = 0.07). A higher number of macrophages expressed CD163 at low intensity in late-stage Crohn's disease ( p = 0.04). The concentration of IL-15 ( p = 0.02) and IL-23A ( p = 0.05) was higher in healthy ileal mucosa of early-stage patients. In the external cohort, expressions of DEFB1 ( p = 0.03), DEFB4A ( p = 0.01), IL-2 ( p = 0.04), and IL-3 ( p = 0.03) increased in patients with late-stage Crohn's disease.

LIMITATIONS

A relatively small number of patients, especially in the newly diagnosed group.

CONCLUSIONS

In newly diagnosed Crohn's disease, high levels of IL-15 and IL-23 in healthy mucosa suggest that innate immunity is the starter of acute inflammation. Moreover, M2 macrophages increase in the healthy mucosa of patients with late-stage Crohn's disease, suggesting that reparative and profibrotic processes are predominant in the long term, and in this phase, anti-inflammatory therapy may be less efficient. See Video Abstract .

ACTIVACIN DE LA INMUNIDAD INNATA EN LA RECIENTEMENTE DIAGNOSTICADA ENFERMEDAD DE CROHN ILEOCLICA UN ESTUDIO DE COHORTE

ANTECEDENTES:Estudios recientes demostraron que la cirugía temprana para la enfermedad de Crohn (EC) conduce a una menor tasa de recurrencia. Sin embargo, se desconoce el mecanismo subyacente.OBJETIVO:El estudio tiene como objetivo analizar el microambiente de la inmunidad innata en la mucosa ileal según la duración de la EC.DISEÑO:Un estudio de cohorte prospectivo.AJUSTES:Centro terciario de referencia para cirugía de EII.PACIENTES:Fueron registrados de manera prospectiva y consecutiva 88 pacientes con EC sometidos a resección ileocolónica. Se obtuvieron muestras de mucosa ileal, tanto del íleon sano como del íleon inflamado. Los datos se analizaron como una cohorte de validación externa.PRINCIPALES MEDIDAS DE RESULTADO:Fueron evaluados la infiltración de neutrófilos por histología y la subpoblación de macrófagos por inmunohistoquímica. La expresión de TLR2, TLR4, TLR5, DEFB1, DEFB4A, DEFB103, DEFA5 y DEFA6 fueron cuantificados mediante qPCR en tiempo real. Las concentraciones de BDNF, CCL-11, ICAM-1, IL-1A, IL-1B, IL-1RN, IL-12 p40, IL-12 p70, IL-15, IL-17A, IL-23A, MMP-3, CCL-3, KITLG, VEGFA se determinaron con ensayo inmunométrico.RESULTADOS:La infiltración de neutrófilos se correlaciona inversamente con la duración de la enfermedad. La expresión del ARNm de DEFB4A mostro una tendencia a ser mayor en la EC en etapa tardía ( p = 0,07). Un mayor número de macrófagos expresaron CD163 a baja intensidad en la etapa tardía ( p = 0,04). La concentración de IL15 ( p = 0,02) e IL23A ( p = 0,05) fue mayor en la mucosa ileal sana de pacientes en estadio temprano. En la cohorte externa, la expresión de DEFB1 ( p = 0,03) y DEFB4A ( p = 0,01), IL2 ( p = 0,04) e IL3 ( p = 0,03) aumentó en pacientes en etapa tardía.LIMITACIONES:Un número relativamente pequeño de pacientes, especialmente en el grupo recién diagnosticado.CONCLUSIONES:En la EC recién diagnosticada, los altos niveles de IL-15 e IL-23 en la mucosa sana sugieren que la inmunidad innata es el promotor de la inflamación aguda. Además, los macrófagos M2 aumentan en la mucosa sana de pacientes con EC en etapa tardía, lo que sugiere que los procesos reparadores y profibróticos son predominantes a largo plazo y en esta fase, la terapia antiinflamatoria puede ser menos eficiente. (Traducción-Dr. Osvaldo Gauto ).

Stimuli-Mediated Macrophage Switching, Unraveling the Dynamics at the Nanoplatforms-Macrophage Interface

Macrophages play an essential role in immunotherapy and tissue regeneration owing to their remarkable plasticity and diverse functions. Recent bioengineering developments have focused on using external physical stimuli such as electric and magnetic fields, temperature, and compressive stress, among others, on micro/nanostructures to induce macrophage polarization, thereby increasing their therapeutic potential. However, it is difficult to find a concise review of the interaction between physical stimuli, advanced micro/nanostructures, and macrophage polarization. This review examines the present research on physical stimuli-induced macrophage polarization on micro/nanoplatforms, emphasizing the synergistic role of fabricated structure and stimulation for advanced immunotherapy and tissue regeneration. A concise overview of the research advancements investigating the impact of physical stimuli, including electric fields, magnetic fields, compressive forces, fluid shear stress, photothermal stimuli, and multiple stimulations on the polarization of macrophages within complex engineered structures, is provided. The prospective implications of these strategies in regenerative medicine and immunotherapeutic approaches are highlighted. This review will aid in creating stimuli-responsive platforms for immunomodulation and tissue regeneration.

Phacolytic Glaucoma Diagnosed by Cytopathology: A Clinicopathologic Case Series

PURPOSE

The aim of this study was to describe the clinical presentation, histopathologic characteristics, and management of phacolytic glaucoma.

PATIENTS AND METHODS

The database at the Florida Lions Ocular Pathology Laboratory was searched for surgical specimens at the Bascom Palmer Eye Institute. Patients with a diagnosis of "phacolytic glaucoma" on cytopathology between the years of 1997 and 2023 were included (n = 15). Patient demographics, anatomic site, laterality, clinical features, and ocular examination findings were obtained from available medical records.

RESULTS

The diagnosis of phacolytic glaucoma was established by light microscopic examination of cytology specimens in 15 eyes (Right = 8, Left = 6, not specified = 1). Between 1997 and 2023, there were 32 cytopathology cases with a preoperative diagnosis of phacolytic glaucoma. From this group of 15 cases, there were nine males and six females. Mean age was 64.2 years (Range: 39-87). Thirteen samples were from the anterior chamber and two were obtained from the vitreous. All 15 cases (100%) demonstrated histiocytes with engulfed foamy and/or granular presumed lenticular material. CD68 immunohistochemistry was positive within histiocytes in four cases that were stained (100%). Of the available medical records, clinical features, and ocular examination findings included: eye redness, decreased vision, eye pain, anterior chamber inflammation, dislocated or subluxed crystalline lens, cataract, and elevated intraocular pressure (average = 41.3 ± 8.67 mm Hg).

CONCLUSIONS

Phacolytic glaucoma is a rare complication of mature/hypermature cataracts that presents with ocular pain, decreased vision, and anterior chamber inflammation. AC paracentesis with cytopathologic evaluation is a minimally invasive, rapid technique that can aid in the diagnosis and management of this disease.

Tumor and Peritoneum-Associated Macrophage Gene Signature as a Novel Molecular Biomarker in Gastric Cancer

A spectrum of immune states resulting from tumor resident macrophages and T-lymphocytes in the solid tumor microenvironment correlates with patient outcomes. We hypothesized that in gastric cancer (GC), macrophages in a polarized immunosuppressive transcriptional state would be prognostic of poor survival. We derived transcriptomic signatures for M2 (M2TS, MRC1; MS4A4A; CD36; CCL13; CCL18; CCL23; SLC38A6; FGL2; FN1; MAF) and M1 (M1TS, CCR7; IL2RA; CXCL11; CCL19; CXCL10; PLA1A; PTX3) macrophages, and cytolytic T-lymphocytes (CTLTS, GZMA; GZMB; GZMH; GZMM; PRF1). Primary GC in a TCGA stomach cancer dataset was evaluated for signature expressions, and a log-rank test determined overall survival (OS) and the disease-free interval (DFI). In 341 TCGA GC entries, high M2TS expression was associated with histological types and later stages. Low M2TS expression was associated with significantly better 5-year OS and DFI. We validated M2TS in prospectively collected peritoneal fluid of a GC patient cohort (n = 28). Single-cell RNA sequencing was used for signature expression in CD68+CD163+ cells and the log-rank test compared OS. GC patients with high M2TS in CD68+CD163+ cells in their peritoneal fluid had significantly worse OS than those with low expression. Multivariate analyses confirmed M2TS was significantly and independently associated with survival. As an independent predictor of poor survival, M2TS may be prognostic in primary tumors and peritoneal fluid of GC patients.

[18F]FDG PET/CT Signal Correlates with Neoangiogenesis Markers in Patients with Fibrotic Interstitial Lung Disease Who Underwent Lung Biopsy: Implication for the Use of PET/CT in Diffuse Lung Diseases

The use of [18F]FDG PET/CT as a biomarker in diffuse lung diseases is increasingly recognized. We investigated the correlation between [18F]FDG uptake with histologic markers on lung biopsy of patients with fibrotic interstitial lung disease (fILD). Methods: We recruited 18 patients with fILD awaiting lung biopsy for [18F]FDG PET/CT. We derived a target-to-background ratio (TBR) of maximum pulmonary uptake of [18F]FDG (SUVmax) divided by the lung background (SUVmin). Consecutive paraffin-embedded lung biopsy sections were immunostained for alveolar and interstitial macrophages (CD68), microvessel density (MVD) (CD31 and CD105/endoglin), and glucose transporter 1. MVD was expressed as vessel area percentage per high-power field (Va%/hpf). Differences in imaging and angiogenesis markers between histologic usual interstitial pneumonia (UIP) and non-UIP were assessed using a nonparametric Mann-Whitney test. Correlation of imaging with angiogenesis markers was assessed using the nonparametric Spearman rank correlation. Univariate Kaplan-Meier survival analysis assessed the difference in the survival curves for each of the angiogenesis markers (separated by their respective optimal cutoff) using the log-rank test. Statistical analysis was performed using SPSS. Results: In total, 18 patients were followed for an average of 41.36 mo (range, 5.69-132.46 mo; median, 30.07 mo). Only CD105 MVD showed a significantly positive correlation with [18F]FDG TBR (Spearman rank correlation, 0.556; P < 0.05, n = 13). There was no correlation between [18F]FDG uptake and macrophage expression of glucose transporter 1. CD105 and CD31 were higher for UIP than for non-UIP, with CD105 reaching statistical significance (P = 0.011). In all patients, MVD assessed with either CD105 or CD31 quantification on biopsy predicted overall survival. Patients with CD105 MVD of less than 12 Va%/hpf or CD31 MVD of less than 35 Va%/hpf had a significantly better prognosis (no deaths during follow-up in the case of CD105) than did patients with higher scores of CD105 MVD (median survival, 35 mo; P = 0.041, n = 13) or CD31 MVD (median survival, 28 mo; P = 0.014, n = 13). Conclusion: Previous work has used [18F]FDG uptake in PET/CT as a biomarker in fILD. Here, we highlight a correlation between angiogenesis and [18F]FDG TBR. We show that MVD is higher for UIP than for non-UIP and is associated with mortality in patients with fILD. These data set the scene to investigate the potential role of vasculature and angiogenesis in fibrosis.

Cardiac injury activates STING signaling via upregulating SIRT6 in macrophages after myocardial infarction

AIMS

This work sought to investigate the mechanism underlying the STING signaling pathway during myocardial infarction (MI), and explore the involvement and the role of SIRT6 in the process.

MAIN METHODS

Mice underwent the surgery of permanent left anterior descending (LAD) artery constriction. Primary cardiomyocytes (CMs) and fibroblasts were subjected to hypoxia to mimic MI in vitro. STING expression was assessed in the infarct heart, and the effect of STING inhibition on cardiac fibrosis was explored. This study also evaluated the regulatory effect of STING by SIRT6 in macrophages.

KEY FINDINGS

STING protein was increased in the infarct heart tissue, highlighting its involvement in the post-MI inflammatory response. Hypoxia-induced death of CMs and fibroblasts contributed to the upregulation of STING in macrophages, establishing the involvement of STING in the intercellular signaling during MI. Inhibition of STING resulted in a significant reduction of cardiac fibrosis at day 14 after MI. Additionally, this study identified SIRT6 as a key regulator of STING via influencing its acetylation and ubiquitination in macrophages, providing novel insights into the posttranscriptional modification and expression of STING at the acute phase after myocardial infarction.

SIGNIFICANCE

This work shows the key role of SIRT6/STING signaling in the pathogenesis of cardiac injury after MI, suggesting that targeting this regulatory pathway could be a promising strategy to attenuate cardiac fibrosis after MI.

TPX2 influences the regulation of macrophage polarization via the NF-κB pathway in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the most prevalent subtype of lung cancer. Xklp2 targeting protein (TPX2), a crucial oncogene exhibits high expression levels in various cancers including LUAD, may serve as a potential target for clinical intervention. Additionally, the growth of lung cancer is significantly influenced by the tumor microenvironment (TME). However, there have been no reports on experiments investigating TPX2 in tumor-infiltrating immune cells (TIICs) in LUAD. Therefore, we verified the effect of TPX2 on macrophage polarization both in vitro and in vivo.

METHODS

We silenced TPX2 the gene in A549 cells and collected supernatants for macrophage culture. We then used flow cytometry and Western blot analysis to assess macrophage polarization. Additionally, we verified the expression of macrophage colony-stimulating factor (M-CSF), and CD163 by immunohistochemistry (IHC) in tissue specimens from LUAD patients. Finally, pathways related to TPX2's regulatory function in macrophage polarization were analyzed through whole genome sequencing, Western blotting, and immunofluorescence (IF).

RESULTS

Silencing TPX2 can affect the ratio of CD80+ M1/CD163+ M2 and reduce the polarization of M0 macrophages to CD163+ M2 macrophages mainly by inhibiting the expression of M-CSF. In human LUAD tissues, the expression levels of TPX2, M-CSF and CD163 increased with the degree of differentiation. Silencing TPX2 inhibits the NF-κB signaling pathway, thereby reducing the expression of M-CSF, and affecting macrophage polarization.

CONCLUSION

Silencing TPX2 can inhibit the expression of M-CSF by blocking the NF-κB signal, thereby reducing CD163+ M2 macrophage polarization. The TPX2/NF-κB/M-CSF signaling axis may be involved in regulating macrophage polarization.

Macrophage polarization in lymph node granulomas from cattle and pigs naturally infected with Mycobacterium tuberculosis complex

Tuberculosis in animals is caused by members of the Mycobacterium tuberculosis complex (MTC), with the tuberculous granuloma being the main characteristic lesion. The macrophage is the main cell type involved in the development of the granuloma and presents a wide plasticity ranging from polarization to classically activated or pro-inflammatory macrophages (M1) or to alternatively activated or anti-inflammatory macrophages (M2). Thus, this study aimed to analyze macrophage polarization in granulomas from cattle and pig lymph nodes naturally infected with MTC. Tuberculous granulomas were microscopically categorized into four stages and a panel of myeloid cells (CD172a/calprotectin), M1 macrophage polarization (iNOS/CD68/CD107a), and M2 macrophage polarization (Arg1/CD163) markers were analyzed by immunohistochemistry. CD172a and calprotectin followed the same kinetics, having greater expression in late-stage granulomas in pigs. iNOS and CD68 had higher expression in cattle compared with pigs, and the expression was higher in early-stage granulomas. CD107a immunolabeling was only observed in porcine granulomas, with a higher expression in stage I granulomas. Arg1+ cells were significantly higher in pigs than in cattle, particularly in late-stage granulomas. Quantitative analysis of CD163+ cells showed similar kinetics in both species with a consistent frequency of immunolabeled cells throughout the different stages of the granuloma. Our results indicate that M1 macrophage polarization prevails in cattle during early-stage granulomas (stages I and II), whereas M2 phenotype is observed in later stages. Contrary, and mainly due to the expression of Arg1, M2 macrophage polarization is predominant in pigs in all granuloma stages.

Pulmonary inflammation decreases with ultra-protective ventilation in experimental ARDS under VV-ECMO: a positron emission tomography study

Background

Experimentally, ultra-protective ventilation (UPV, tidal volumes [VT] < 4 mL.kg-1) strategies in conjunction with veno-venous extracorporeal membrane oxygenation (VV-ECMO) are associated with lesser ventilator-induced lung injuries (VILI) during acute respiratory distress syndrome (ARDS). However, whether these strategies reduce lung inflammation more effectively than protective ventilation (PV) remains unclear. We aimed to demonstrate that a UPV strategy decreases acute lung inflammation in comparison with PV in an experimental swine model of ARDS.

Methods

ARDS was induced by tracheal instillation of chlorhydric acid in sedated and paralyzed animals under mechanical ventilation. Animals were randomized to receive either UPV (VT 1 mL.kg-1, positive end-expiration pressure [PEEP] set to obtain plateau pressure between 20 and 25 cmH2O and respiratory rate [RR] at 5 min-1 under VV-ECMO) or PV (VT 6 mL.kg-1, PEEP set to obtain plateau pressure between 28 and 30 cmH2O and RR at 25 min-1) during 4 h. After 4 h, a positron emission tomography with [11C](R)-PK11195 (ligand to TSPO-bearing macrophages) injection was realized, coupled with quantitative computerized tomography (CT). Pharmacokinetic multicompartment models were used to quantify regional [11C](R)-PK11195 lung uptake. [11C](R)-PK11195 lung uptake and CT-derived respiratory variables were studied regionally across eight lung regions distributed along the antero-posterior axis.

Results

Five pigs were randomized to each study group. Arterial O2 partial pressure to inspired O2 fraction were not significantly different between study groups after experimental ARDS induction (75 [68-80] mmHg in a PV group vs. 87 [69-133] mmHg in a UPV group, p = 0.20). Compared to PV animals, UPV animals exhibited a significant decrease in the regional non-aerated compartment in the posterior lung levels, in mechanical power, and in regional dynamic strain and no statistical difference in tidal hyperinflation after 4 h. UPV animals had a significantly lower [11C](R)-PK11195 uptake, compared to PV animals (non-displaceable binding potential 0.35 [IQR, 0.20-0.59] in UPV animals and 1.01 [IQR, 0.75-1.59] in PV animals, p = 0.01). Regional [11C](R)-PK11195 uptake was independently associated with the interaction of regional tidal hyperinflation and regional lung compliance.

Conclusion

In an experimental model of ARDS, 4 h of UPV strategy significantly decreased lung inflammation, in relation to the control of VT-derived determinants of VILI.

Peripheral macrophages in the development and progression of structural cerebrovascular pathologies

The human cerebrovascular system is responsible for maintaining neural function through oxygenation, nutrient supply, filtration of toxins, and additional specialized tasks. While the cerebrovascular system has resilience imparted by elaborate redundant collateral circulation from supportive tertiary structures, it is not infallible, and is susceptible to developing structural vascular abnormalities. The causes of this class of structural cerebrovascular diseases can be broadly categorized as 1) intrinsic developmental diseases resulting from genetic or other underlying aberrations (arteriovenous malformations and cavernous malformations) or 2) extrinsic acquired diseases that cause compensatory mechanisms to drive vascular remodeling (aneurysms and arteriovenous fistulae). Cerebrovascular diseases of both types pose significant risks to patients, in some cases leading to death or disability. The drivers of such diseases are extensive, yet inflammation is intimately tied to all of their progressions. Central to this inflammatory hypothesis is the role of peripheral macrophages; targeting this critical cell type may lead to diagnostic and therapeutic advancement in this area. Here, we comprehensively review the role that peripheral macrophages play in cerebrovascular pathogenesis, provide a schema through which macrophage behavior can be understood in cerebrovascular pathologies, and describe emerging diagnostic and therapeutic avenues in this area.

The clinicopathological impact of tumor-associated macrophages in patients with cutaneous malignant melanoma

BACKGROUND

Tumor-associated macrophages (TAMs) are an immune component of the cutaneous malignant melanoma (CMM) microenvironment and affect tumor growth. TAMs can polarize into different phenotypes, that is, proinflammatory M1 and anti-inflammatory M2 macrophages. However, the role of the macrophage phenotype in CMM remains unclear.

METHODS

We examined 88 patients with CMM. Tissue microarrays were constructed, and the density of M1 and M2 macrophages was analyzed by immunohistochemistry. Immune cells coexpressing CD68 and phosphorylated signal transducer and activator of transcription 1 (pSTAT1) were considered M1 macrophages, whereas those coexpressing CD68 and c-macrophage activating factor (c-Maf) were defined as M2 macrophages. These TAMs were counted, and the relationships between the density of M1 and M2 macrophages and clinicopathological factors including prognosis were investigated.

RESULTS

The CD68/c-Maf score ranged from 0 to 34 (median: 5.5). The patients were divided based on the median score into the CD68/c-Maf high (≥5.5) and low (<5.5) expression groups. Univariate and multivariate analyses revealed that CD68/c-Maf expression was an independent predictive factor for progression-free survival and an independent prognostic factor for overall survival. CD68/pSTAT1 expression was found in only two patients.

CONCLUSION

We suggest that CD68/pSTAT1 coexpression is rarely observed in patients with CMM, and high CD68/c-Maf expression is a predictor of worse prognosis in these patients.

Melatonin modulates L-arginine metabolism in tumor-associated macrophages by targeting arginase 1 in lymphoma

L-Arginine metabolism plays a crucial role in determining the M1/M2 polarization of macrophages. The M1 macrophages express inducible nitric oxide synthase (iNOS), while the M2 macrophages express arginase 1 and metabolize arginine into nitric oxide and urea, respectively. The tumor microenvironment promotes M2 macrophage polarization and consequently switches the metabolic fate of arginine from nitric oxide towards urea production. Importantly, infiltration of M2 macrophages or tumor-associated macrophages (TAMs) has been correlated with poor prognosis of various cancer types. Melatonin is well reported to have antitumor and immunomodulatory properties. However, whether and how it impacts the polarization of TAMs has not been elucidated. Considering the crucial role of arginine metabolism in macrophage polarization, we were interested to know the fate of L-arginine in TAMs and whether it can be reinstated by melatonin or not. We used a murine model of Dalton's lymphoma and established an in vitro model of TAMs. For TAMs, we used the ascitic fluid of tumor-bearing hosts to activate the macrophages in the presence and absence of lipopolysaccharide (LPS). In these groups, L-arginine metabolism was evaluated, and then the effect of melatonin was assessed in these groups, wherein the metabolic fate of arginine as well as the expression of iNOS and arginase 1 were checked. Furthermore, in the in vivo system of the tumor-bearing host, the effect of melatonin was assessed. The in vitro model of TAMs showed a Th2 cytokine profile, reduced phagocytic activity, and increased wound healing ability. Upon investigating arginine metabolism, we observed high urea levels with increased activity and expression of arginase 1 in TAMs. Furthermore, we observed reduced levels of LPS-induced nitric oxide in TAMs; however, their iNOS expression was comparable. With melatonin treatment, urea level decreased significantly, while the reduction in nitric oxide level was not as significant as observed in its absence in TAMs. Also, melatonin significantly reduced arginase activity and expression at the transcriptional and translational levels, while iNOS expression was affected only at the translational level. This effect was further investigated in the in vivo system, wherein melatonin treatment reversed the metabolic fate of arginine, from urea towards nitric oxide, within the tumor microenvironment. This effect was further correlated with pro-apoptotic tumor cell death in the in vivo system. Our results reinforced the immunomodulatory role of melatonin and offered a strong prospect for activating the anti-tumor immune response in cancer conditions.

CD163 protein inhibits lipopolysaccharide-induced macrophage transformation from M2 to M1 involved in disruption of the TWEAK-Fn14 interaction

Macrophages play a crucial role in regulating inflammation and innate immune responses, and their polarization into distinct phenotypes, such as M1 and M2, is involved in various diseases. However, the specific role of CD163, a scavenger receptor expressed by macrophages, in the transformation of M2 to M1 macrophages remains unclear. Here, dexamethasone-induced M2 macrophages were treated with lipopolysaccharide (LPS) to induce the transformation of M2 to M1 macrophages. We found that treatment with lipopolysaccharide (LPS) induced the transformation of M2-like macrophages to an M1-like phenotype, as evidenced by increased mRNA levels of Il1b and Tnf, decreased mRNA levels of Cd206 and Il10, and increased TNF-α secretion. Knockdown of CD163 enhanced the phenotypic features of M1 macrophages, while treatment with recombinant CD163 protein (rmCD163) inhibited the LPS-induced M2-to-M1 transformation. Furthermore, LPS stimulation resulted in the activation of P38, ERK, JNK, and NF-κB P65 signaling pathways, and this activation was increased after CD163 knockdown and suppressed after rmCD163 treatment during macrophage transformation. Additionally, we observed that LPS treatment reduced the expression of CD163 in dexamethasone-induced M2 macrophages, leading to a decrease in the CD163-TWEAK complex and an increase in the interaction between TWEAK and Fn14. Overall, our findings suggest that rmCD163 can inhibit the LPS-induced transformation of M2 macrophages to M1 by disrupting the TWEAK-Fn14 interaction and modulating the MAPK-NF-κB pathway.

Discovery of β-sitosterol's effects on molecular changes in rat diabetic wounds and its impact on angiogenesis and macrophages

Diabetes care, particularly for diabetic foot ulcers (DFUs)-related complications, increases treatment costs substantially. Failure to provide timely and appropriate treatment for severe DFUs significantly increases amputation risk. Neovascularization and macrophage polarization play an important role in diabetic wound healing during different stages of the wound repair process. Therefore, a new treatment method that promotes neovascularization and macrophage polarization may accelerate diabetic wound healing. β-sitosterol possesses anti-inflammatory, lipid-lowering, and antidiabetic properties. However, its therapeutic potential in diabetic wound healing remains underexplored. This study evaluated the healing effects of β-sitosterol on diabetic ulcer wounds in rats. We found that β-sitosterol can promote angiogenesis, alternatively activated macrophages (M2 macrophage) proliferation, and collagen synthesis in diabetic wounds. Transcriptomics analysis and proteomics analysis revealed that MAPK, mTOR and VEGF signaling pathways were enriched in β-sitosterol-treated wounds. Molecular docking revealed Ndufb5 maybe the target of β-sitosterol-treated wounds. Our findings confirm the significant diabetic wound healing effects of β-sitosterol in a rat model. β-sitosterol treatment to diabetic wounds accelerates wound healing through promoting M2 macrophage proliferation and angiogenesis. Interestingly, we also found that the process of M2 macrophage proliferation accompanies angiogenesis. Thus, β-sitosterol may be a promising therapeutic approach to enhance diabetic wound healing and reduce amputation in diabetes.

Tumor-associated macrophages and PD-L1 in prostate cancer: a possible key to unlocking immunotherapy efficacy

PURPOSE

Prostate cancer (PCa) is often considered as a "cold" tumor with low responsiveness to immunotherapy. Recent evidence suggests the activation of specific immune cells, such as tumor-associated macrophages (TAMs), could potentially influence the efficacy of immunotherapy in PCa. However, the relationship between TAMs and PD-L1, a significant regulator in immunotherapy, within PCa remains unexplored.

METHODS

In this study, we assessed TAM infiltration and PD-L1 expression levels in a local cohort of 95 PCa tissue samples and two publicly available PCa datasets. We employed a combination of bioinformatics and experimental techniques, including gene set enrichment analysis, CIBERSORTx, tissue microarray, immunohistochemistry staining, and analysis of single-cell sequencing datasets, to provide a comprehensive understanding of the association between PD-L1 and TAMs in the PCa microenvironment.

RESULTS

The study showed that CD68+ TAMs and CD163+ TAMs (M2-TAMs) were more abundant in the tumor microenvironment than in non-cancerous surrounding tissues. The infiltration of CD163+ TAMs was significantly associated with the Gleason score and risk stratification of PCa. Importantly, elevated PD-L1 expression correlated significantly with high infiltration of CD163+ TAMs. Furthermore, patients displaying high levels of CD163+ TAMs and PD-L1 expression exhibited shorter times to biochemical recurrence-free survival.

CONCLUSION

Our study suggests that CD163+ TAMs are closely associated with PD-L1 expression and can act as a valuable prognostic indicator for PCa. The high infiltration of M2-TAMs, coupled with the overexpression of PD-L1, may contribute to immune escape mechanisms in PCa, thereby influencing disease prognosis.

2-Deoxy-D-glucose ameliorates inflammation and fibrosis in a silicosis mouse model by inhibiting hypoxia-inducible factor-1α in alveolar macrophages

Inhaling silica causes the occupational illness silicosis, which mostly results in the gradual fibrosis of lung tissue. Previous research has demonstrated that hypoxia-inducible factor-1α (HIF-1α) and glycolysis-related genes are up-regulated in silicosis. The role of 2-deoxy-D-glucose (2-DG) as an inhibitor of glycolysis in silicosis mouse models and its molecular mechanisms remain unclear. Therefore, we used 2-DG to observe its effect on pulmonary inflammation and fibrosis in a silicosis mouse model. Furthermore, in vitro cell experiments were conducted to explore the specific mechanisms of HIF-1α. Our study found that 2-DG down-regulated HIF-1α levels in alveolar macrophages induced by silica exposure and reduced the interleukin-1β (IL-1β) level in pulmonary inflammation. Additionally, 2-DG reduced silica-induced pulmonary fibrosis. From these findings, we hypothesize that 2-DG reduced glucose transporter 1 (GLUT1) expression by inhibiting glycolysis, which inhibits the expression of HIF-1α and ultimately reduces transcription of the inflammatory cytokine, IL-1β, thus alleviating lung damage. Therefore, we elucidated the important regulatory role of HIF-1α in an experimental silicosis model and the potential defense mechanisms of 2-DG. These results provide a possible effective strategy for 2-DG in the treatment of silicosis.

Azithromycin with scaling and root planing versus scaling and root planing alone in the treatment of periodontitis: A randomized controlled trial

Background

The growing interest in the possibilities of macrophages modulation with therapeutic purposes promotes new approaches for periodontitis treatment.

Aim

The aim of this randomized controlled open clinical study was to evaluate the early clinical and immunological effects of the long-course azithromycin as an adjunct to scaling and root planing in periodontitis.

Methods

50 patients (with stage I-III, grade A/B periodontitis) and 22 periodontally healthy volunteers as the reference group were recruited. Following scaling and root planing (SRP), the patients were randomly assigned to one of two treatment modalities: SRP only (n = 25) and adjunct azithromycin (Az) treatment (n = 25). The patients were monitored at baseline, and 30 ± 5 days after therapy. Clinical attachment loss (CAL), periodontal probing depth (PPD) and bleeding on probing (BoP) were evaluated. Secondary outcome measures included mean changes in single-positive CD68 + and CD163 + macrophages (Mφs) density and ratio, evaluated by immunohistochemistry, and IL1-β, IL-6, IL-10, TGF-β levels, detected by ELISA.

Results

At 1 month both groups showed significant improvements of CAL, PPD and BoP, without significant added benefit in terms of CAL, PPD and BoP of Az. But Az increased the density of CD68 + and CD163 + Mφs (P < 0.0001), decreased the CD68+/CD163 + ratio (P = 0.043), decreased IL-1β (P < 0.01), IL-6 (P < 0.001) levels, and increased IL-10 (P < 0.0001) and TGF-β (P < 0.001) levels compared to SRP and periodontitis at baseline.

Conclusion

The long course of Az demonstrated modulation of CD68 + and CD163 + Mφs towards M2 polarization, which may play a significant role in achieving favorable long-term treatment outcomes. ClinicalTrials.gov.

The influence of inflammation on the characteristics of adipose-derived mesenchymal stem cells (ADMSCs) and tissue repair capability in a hepatic injury mouse model

BACKGROUND

Mesenchymal stem cells (MSCs) are adult stem cells with self-renewal and multi-directional differentiation potential and possess the functions of immunomodulation, regulation of cell growth, and repair of damage. Over recent years, MSCs have been found to regulate the secretion of inflammatory factors and to exert regulatory effects on various lymphocytes in inflammatory states, and on the subsequent repair of tissue damage caused by inflammation. In the present study, we analyzed the effects of tissue inflammation on the characteristics of MSCs.

METHODS

Human fat derived from the infrapatellar fat pad (IPFP) of knees with differing degrees of inflammation was extracted from specimens derived from total knee arthroplasties. HE and immunohistochemical staining was performed to directly observe the evidence and degree of inflammation in human infrapatellar fat pad tissue in order to classify MSCs cells, by their origin, into highly inflamed and lowly inflamed groups, and to study the effect of tissue inflammation on cell acquisition rates via cellular counting data. Flow cytometry assays were performed to investigate the effect of tissue inflammation on MSC surface marker expression. Trilineage differentiation, including osteogenesis, adipogenesis, and chondrogenesis, was performed to assess the effect of tissue inflammation on the ability of MSCs to undergo directed differentiation. The effect of tissue inflammation on the ability of MSCs to proliferate was investigated via clone formation studies. RNA-sequencing was performed to evaluate the transcriptomes of MSCs derived from different areas of inflammation. The effect of tissue inflammation on tissue repair capacity and safety of MSCs was investigated via a murine model of acute liver injury.

RESULTS

The results of cell count data indicate that a high degree of tissue inflammation significantly decreases the acquisition rate of MSCs, and the proportion of CD34+ and CD146+ cells. The results of our trilineage differentiation assay show that a higher degree of inflammation decreases osteogenic differentiation and enhances adipogenic and chondrogenic differentiation of MSCs. However, these differences were not statistically significant. Clone formation assays indicate that the degree of tissue inflammation at the MSC source does not significantly affect the proliferative capacity of MSCs. The transcriptomes of MSCs remain relatively stable in fat pad tissues derived from both highly and lowly inflamed samples. The results of acute liver injury investigations in mice indicate that MSCs of high and low inflammatory tissue origin have no significant difference in their tissue repair capability.

CONCLUSIONS

High tissue inflammation at the source of MSCs reduces the acquisition rate of MSCs and the percentage of CD34+ and CD146+ cells acquisition. However, source tissue inflammation may not significantly affect trilineage differentiation potential and proliferative capacity of MSCs. Also, MSCs obtained from differing source degrees of inflammation retain stable and similar transcriptomic profile and are both safe and efficacious for tissue repair/regeneration without detectable differences.

The Role of Macrophages in Sarcoma Tumor Microenvironment and Treatment

Sarcomas are a heterogeneous group of malignant mesenchymal tumors, including soft tissue and bone sarcomas. Macrophages in the tumor microenvironment, involved in immunosuppression and leading to tumor development, are called tumor-associated macrophages (TAMs). TAMs are very important in modulating the microenvironment of sarcomas by expressing specific markers and secreting factors that influence immune and tumor cells. They are involved in many signaling pathways, such as p-STAT3/p-Erk1/2, PI3K/Akt, JAK/MAPK, and JAK/STAT3. TAMs also significantly impact the clinical outcomes of patients suffering from sarcomas and are mainly related to poor overall survival rates among bone and soft tissue sarcomas, for example, chondrosarcoma, osteosarcoma, liposarcoma, synovial sarcoma, and undifferentiated pleomorphic sarcoma. This review summarizes the current knowledge on TAMs in sarcomas, focusing on specific markers on sarcoma cells, cell-cell interactions, and the possibly involved molecular pathways. Furthermore, we discuss the clinical significance of macrophages in sarcomas as a potential target for new therapies, presenting clinical relevance, possible new treatment options, and ongoing clinical trials using TAMs in sarcoma treatment.

Prognostic Impact of Tumor-Associated Macrophage-Related Markers in Patients with Adenocarcinoma of the Lung

BACKGROUND

Macrophage polarization is an important pathogenetic factor in neoplastic diseases. Phosphorylated signal transducer and activator of transcription 1 (phospho-STAT1) regulates the M1 phenotype, and c-Maf regulates the M2 phenotype. However, the role of macrophage phenotype in lung adenocarcinoma (LAD) remains unclear.

PATIENTS AND METHODS

We examined whether the density of M1 and M2 macrophages was associated with prognosis in patients with LAD using double-labeling immunohistochemistry. In addition, programmed death ligand 1 (PD-L1) expression was investigated. Immune cells coexpressing CD68 and phospho-STAT1 were considered M1 macrophages, whereas those coexpressing CD68 and c-Maf were recognized as M2 macrophages. Patients with LAD (N = 307) were divided into two cohorts (n = 100 and n = 207) to evaluate the associations of M1 and M2 phenotypes with prognosis in patients with LAD. We determined the cut-off values of CD68/phospho-STAT1-positive cells and CD68/c-Maf-positive cells to assess correlations with overall survival (OS) using receiver operating characteristic curve analysis in the first cohort.

RESULTS

According to the cut-off values of 5 or less CD68/phospho-STAT1-positive cells and more than 11 CD68/c-Maf-positive cells, high expression of CD68/c-Maf and low expression of CD68/Phospho-STAT1 were identified as independent prognostic markers for OS and disease-free survival (DFS). Moreover, the M1/M2 ratio (0.19 or less) was a poor prognostic factor for OS and DFS. However, PD-L1 expression did not correlate with patient outcomes.

CONCLUSIONS

Overall, these findings suggest that double immunostaining of markers of phospho-STAT1 (M1) and c-Maf (M2) can be used as prognostic indicators for patients with LAD.

Osteoprotective Role of the Mir338 Cluster Ablation during Periodontitis

Periodontitis is a chronic inflammatory disease that compromises the integrity of the supporting tissues of the teeth and leads to the loss of the alveolar bone. The Mir338 cluster has been proven to be a potential target for the treatment of osteoporosis and is also enriched in gingival tissues with periodontitis; however, its role in periodontitis remains unknown. Here, we aimed to use periodontitis as a model to expand our understanding of the Mir338 cluster in osteoimmunology and propose a new target to protect against bone loss during periodontitis progression. Significant enrichment of the Mir338 cluster was validated in gingival tissues from patients with chronic periodontitis and a ligature-induced periodontitis mouse model. In vivo, attenuation of alveolar bone loss after 7 d of ligature was observed in the Mir338 cluster knockout (KO) mice. Interestingly, immunofluorescence and RNA sequencing showed that ablation of the Mir338 cluster reduced osteoclast formation and elevated the inflammatory response, with enrichment of IFN-γ and JAK-STAT signaling pathways. Ablation of the Mir338 cluster also skewed macrophages toward the M1 phenotype and inhibited osteoclastogenesis via Stat1 in vitro and in vivo. Furthermore, the local administration of miR-338-3p antagomir prevented alveolar bone loss from periodontitis. In conclusion, the Mir338 cluster balanced M1 macrophage polarization and osteoclastogenesis and could serve as a novel therapeutic target against periodontitis-related alveolar bone loss.

Effect of Oleoylethanolamide-Based Dietary Supplement on Systemic Inflammation in the Development of Alimentary-Induced Obesity in Mice

The complex effect of oleoylethanolamide-based dietary supplement (OEA-DS) was studied in a model of diet-induced obesity in mice. Physiological, biochemical, and immunohistochemical methods were used to reveal differences in the changes in the weight of experimental animals, morphological changes in the spleen tissues, and changes in the cytokine expression profile in the spleen, blood plasma, and macrophage cell culture. First, it is shown that a hypercaloric diet high in carbohydrates and cholesterol led to the development of systemic inflammation, accompanied by organ morphological changes and increased production of proinflammatory cytokines. In parallel, the use of OEA-DS reduced the intensity of cellular inflammatory reactions, accompanied by a decrease in markers of cellular inflammation and proliferation, such as CD68, Iba-1, and Ki67 in the spleen tissue, and stabilized the level of proinflammatory cytokines (IL-1β, IL-6, TNFα) both in animals and in cell culture. In addition, in the macrophage cell culture (RAW264.7), it was shown that OEA-DS also suppressed the production of reactive oxygen species and nitrites in LPS-induced inflammation. The results of this study indicate the complex action of OEA-DS in obesity, which includes a reduction of systemic inflammation.

Necrosis reduction efficacy of subdermal biomaterial mediated oxygen delivery in ischemic skin flaps

Inadequate tissue blood supply as may be found in a wound or a poorly vascularised graft, can result in tissue ischemia and necrosis. As revascularization is a slow process relative to the proliferation of bacteria and the onset of tissue necrosis, extensive tissue damage and loss can occur before healing is underway. Necrosis can develop rapidly, and treatment options are limited such that loss of tissue following necrosis onset is considered unavoidable and irreversible. Oxygen delivery from biomaterials exploiting aqueous decomposition of peroxy-compounds has shown some potential in overcoming the supply limitations by creating oxygen concentration gradients higher than can be attained physiologically or by air saturated solutions. We sought to test whether subdermal oxygen delivery from a material composite that was buffered and contained a catalyst, to reduce hydrogen peroxide release, could ameliorate necrosis in a 9 × 2 cm flap in a rat model that reliably underwent 40 % necrosis if untreated. Blood flow in this flap reduced from near normal to essentially zero, along its 9 cm length and subdermal perforator vessel anastomosis was physically prevented by placement of a polymer sheet. In the middle, low blood flow region of the flap, treatment significantly reduced necrosis based on measurements from photographs and histological micrographs. No change was observed in blood vessel density but significant differences in HIF1-α, inducible nitric oxide synthase and liver arginase were observed with oxygen delivery.

Induction of a different immune response in non-titanized compared to titanized polypropylene meshes

It is well known that pelvic organ prolapse (POP) significantly reduces the quality of life of affected women and in many cases requires corrective surgery. Aim of the study was to compare the immune response against titanized versus non-titanized meshes, especially macrophage polarization and immune checkpoint association. For this, we analyzed 644 POP surgeries, which were performed between 2017 and 2022, in our department. Four of them needed revision surgery caused by erosion. We analyzed the influx of CD68 & CD163 positive macrophages and the expression of immune checkpoint molecules PD-L1 and PD1 in these 4 patients. We identified a large number of CD68 and CD163 positive macrophages and additionally a PD-L1 expression of these cells. Based on the in-vivo results, we isolated monocytes and co-cultivated monocytes with different mesh material covered with or without fibroblasts. We identified a significantly enhanced macrophage activation and PD-L1 expression in macrophages surrounding non-titanized polypropylene mesh material. Encapsulation of the material by fibroblasts was crucial for that. Specifically, CD68-positive macrophages are upregulated (p < 0.001), co-expressing PD-L1 (p < 0.001) in monocytes co-cultivated with non-titanized polypropylene meshes. Monocytes co-cultivated with titanized polypropylene meshes showed significantly lower expression of CD163 (p = 0.027) and PD-L1 (p = 0.022). In conclusion, our in vitro data suggest that the titanium coating leads to a decreased polarization of macrophages and to a decreased immune response compared to non-titanized meshes. This could be an indication for the increased incidence of erosion of the non-titanized meshes, which is a severe complication of this procedure and requires revision surgery. STATEMENT OF SIGNIFICANCE: Pelvic organ prolapse is a well-known problem for women and often requires corrective surgery. Polypropylene meshes are often used, which differ in their coating (titanized vs. non-titanized). A severe side effect of these surgeries is mesh erosion, due to onset of inflammation, which requires revision surgery. We examined all erosion cases (4 of 644 patients) with implanted nontitanium-coated meshes by immunohistochemistry and found upregulation of macrophage polarization (as markers CD68 and CD163) and increased expression of the immune checkpoint molecules PD-L1 and PD1. This suggests inflammatory processes and an enhanced immune response. In addition, we set up an in vitro experiment to investigate whether coating plays a role. Here, we demonstrated that the non-titanized meshes elicited a significantly higher immune response in comparison to titanized meshes, which could lead to the higher erosion rate of the non-titanized meshes. Our results highlight the benefit of titanized meshes, which should lead to a lower revision surgery rate and thus improved patient outcome.

Radiographic and histopathological study of gastrointestinal dysmotility in lipopolysaccharide-induced sepsis in the rat

BACKGROUND

Sepsis is a highly incident condition in which a cascade of proinflammatory cytokines is involved. One of its most frequent consequences is ileus, which can increase mortality. Animal models such as that induced by systemic administration of lipopolysaccharide (LPS) are useful to deeply evaluate this condition. The effects of sepsis on the gastrointestinal (GI) tract have been explored but, to our knowledge, in vivo studies showing the motor and histopathological consequences of endotoxemia in an integrated way are lacking. Our aim was to study in rats the effects of sepsis on GI motility, using radiographic methods, and to assess histological damage in several organs.

METHODS

Male rats were intraperitoneally injected with saline or E. coli LPS at 0.1, 1, or 5 mg kg-1 . Barium sulfate was intragastrically administered, and X-rays were performed 0-24 h afterwards. Several organs were collected for organography, histopathology, and immunohistochemistry studies.

KEY RESULTS

All LPS doses caused gastroparesia, whereas changes in intestinal motility were dose-and time-dependent, with an initial phase of hypermotility followed by paralytic ileus. Lung, liver, stomach, ileum, and colon (but not spleen or kidneys) were damaged, and density of neutrophils and activated M2 macrophages and expression of cyclooxygenase 2 were increased in the colon 24 h after LPS 5 mg kg-1 .

CONCLUSIONS AND INFERENCES

Using radiographic, noninvasive methods for the first time, we show that systemic LPS causes dose-, time-, and organ-dependent GI motor effects. Sepsis-induced GI dysmotility is a complex condition whose management needs to take its time-dependent changes into account.

TRAIL promotes the polarization of human macrophages toward a proinflammatory M1 phenotype and is associated with increased survival in cancer patients with high tumor macrophage content

Background

TNF-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily that can either induce cell death or activate survival pathways after binding to death receptors (DRs) DR4 or DR5. TRAIL is investigated as a therapeutic agent in clinical trials due to its selective toxicity to transformed cells. Macrophages can be polarized into pro-inflammatory/tumor-fighting M1 macrophages or anti-inflammatory/tumor-supportive M2 macrophages and an imbalance between M1 and M2 macrophages can promote diseases. Therefore, identifying modulators that regulate macrophage polarization is important to design effective macrophage-targeted immunotherapies. The impact of TRAIL on macrophage polarization is not known.

Methods

Primary human monocyte-derived macrophages were pre-treated with either TRAIL or with DR4 or DR5-specific ligands and then polarized into M1, M2a, or M2c phenotypes in vitro. The expression of M1 and M2 markers in macrophage subtypes was analyzed by RNA sequencing, qPCR, ELISA, and flow cytometry. Furthermore, the cytotoxicity of the macrophages against U937 AML tumor targets was assessed by flow cytometry. TCGA datasets were also analyzed to correlate TRAIL with M1/M2 markers, and the overall survival of cancer patients.

Results

TRAIL increased the expression of M1 markers at both mRNA and protein levels while decreasing the expression of M2 markers at the mRNA level in human macrophages. TRAIL also shifted M2 macrophages towards an M1 phenotype. Our data showed that both DR4 and DR5 death receptors play a role in macrophage polarization. Furthermore, TRAIL enhanced the cytotoxicity of macrophages against the AML cancer cells in vitro. Finally, TRAIL expression was positively correlated with increased expression of M1 markers in the tumors from ovarian and sarcoma cancer patients and longer overall survival in cases with high, but not low, tumor macrophage content.

Conclusions

TRAIL promotes the polarization of human macrophages toward a proinflammatory M1 phenotype via both DR4 and DR5. Our study defines TRAIL as a new regulator of macrophage polarization and suggests that targeting DRs can enhance the anti-tumorigenic response of macrophages in the tumor microenvironment by increasing M1 polarization.

Morphological and lipid metabolism alterations in macrophages exposed to model environmental nanoplastics traced by high-resolution synchrotron techniques

The release of nanoplastics (NPs) in the environment is a significant health concern for long-term exposed humans. Although their usage has certainly revolutionized several application fields, at nanometer size, NPs can easily interact at the cellular level, resulting in potential harmful effects. Micro/Nanoplastics (M/NPs) have a demonstrated impact on mammalian endocrine components, such as the thyroid, adrenal gland, testes, and ovaries, while more investigations on prenatal and postnatal exposure are urgently required. The number of literature studies on the NPs' presence in biological samples is increasing. However, only a few offer a close study on the model environmental NP-immune system interaction exploited by advanced microscopy techniques. The present study highlights substantial morphological and lipid metabolism alterations in human M1 macrophages exposed to labeled polypropylene and polyvinyl chloride nanoparticles (PP and PVC NPs) (20 μg/ml). The results are interpreted by advanced microscopy techniques combined with standard laboratory tests and fluorescence microscopy. We report the accurate detection of polymeric nanoparticles doped with cadmium selenide quantum dots (CdSe-QDs NPs) by following the Se (L line) X-ray fluorescence emission peak at higher sub-cellular resolution, compared to the supportive light fluorescence microscopy. In addition, scanning transmission X-ray microscopy (STXM) imaging successfully revealed morphological changes in NP-exposed macrophages, providing input for Fourier transform infrared (FTIR) spectroscopy analyses, which underlined the chemical modifications in macromolecular components, specifically in lipid response. The present evidence was confirmed by quantifying the lipid droplet (LD) contents in PP and PVC NPs-exposed macrophages (0-100 μg/ml) by Oil Red O staining. Hence, even at experimental NPs' concentrations and incubation time, they do not significantly affect cell viability; they cause an evident lipid metabolism impairment, a hallmark of phagocytosis and oxidative stress.

Identification of immune infiltration-related biomarkers in carotid atherosclerotic plaques

Atherosclerosis is a chronic lipid-driven inflammatory response of the innate and adaptive immune systems, and it is responsible for several cardiovascular ischemic events. The present study aimed to determine immune infiltration-related biomarkers in carotid atherosclerotic plaques (CAPs). Gene expression profiles of CAPs were extracted from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between the CAPs and control groups were screened by the "limma" package in R software. Immune cell infiltration between the CAPs and control groups was evaluated by the single sample gene set enrichment analysis. Key infiltrating immune cells in the CAPs group were screened by the Wilcoxon test and least absolute shrinkage and selection operator regression. The weighted gene co-expression network analysis was used to identify immune cell-related genes. Hub genes were identified by the protein-protein interaction (PPI) network. Receiver operating characteristic curve analysis was performed to assess the gene's ability to differentiate between the CAPs and control groups. Finally, we constructed a miRNA-gene-transcription factor network of hub genes by using the ENCODE database. Eleven different types of immune infiltration-related cells were identified between the CAPs and control groups. A total of 1,586 differentially expressed immunity-related genes were obtained through intersection between DEGs and immune-related genes. Twenty hub genes were screened through the PPI network. Eventually, 7 genes (BTK, LYN, PTPN11, CD163, CD4, ITGAL, and ITGB7) were identified as the hub genes of CAPs, and these genes may serve as the estimable drug targets for patients with CAPs.

IDO Regulates Macrophage Functions by Inhibiting the CCL2/CCR2 Signaling Pathway in Fungal Keratitis

PURPOSE

The aim of this study was to investigate the effects of indoleamine 2,3-dioxygenase (IDO) on macrophage polarization, phagocytosis, and killing through regulation of the CCL2/CCR2 signaling pathway in Aspergillus fumigatus keratitis.

METHODS

In vivo and in vitro experiments were conducted in mice and mouse peritoneal macrophages after infection with A. fumigatus . Clinical scoring, reverse transcription-polymerase chain reaction, and immunofluorescence staining were used to evaluate the fungal keratitis lesions, macrophage-related cytokines, and macrophage recruitment. The expression of CCL2 and CCR2 was detected by reverse transcription-polymerase chain reaction and western blot after pretreatment with or without an IDO inhibitor (1-MT). After pretreatment with 1-MT, a CCR2 antagonist, a CCL2 neutralizing antibody, an IDO agonist (IFNG), and recombinant CCL2 protein (CCL2), the flow cytometry and colony-forming unit counts were used to detect the polarization, phagocytosis, and killing function.

RESULTS

Compared with the control group, the infected eyes showed increased clinical scores, macrophage-related cytokine expression, and macrophage recruitment. 1-MT pretreatment increased the expression of CCL2 and CCR2 and the proportion of CD206+/CD86+ macrophages; macrophages polarized toward the M2 type, with enhanced killing function. CCR2 antagonists and CCL2 neutralizing antibodies reversed the effects of 1-MT. Compared with the infected group, IFNG pretreatment decreased the proportion of CD206+/CD86+ macrophages, and macrophages polarized toward the M1 type, with decreased phagocytosis and impaired killing function. CCL2 reversed the effect of IFNG.

CONCLUSIONS

IDO can promote the polarization of macrophages to the M1 type by blocking the CCL2/CCR2 signaling pathway, inhibiting the phagocytosis and killing function of macrophages, and mediating the protective immune role of A. fumigatus .

The stereological, immunohistological, and gene expression studies in an infected ischemic wound in diabetic rats treated by human adipose-derived stem cells and photobiomodulation

We investigated the impacts of photobiomodulation (PBM) and human allogeneic adipose-derived stem cells (ha-ADS) together and or alone applications on the stereological parameters, immunohistochemical characterizing of M1 and M2 macrophages, and mRNA levels of hypoxia-inducible factor (HIF-1α), basic fibroblast growth factor (bFGF), vascular endothelial growth factor-A (VEGF-A) and stromal cell-derived factor-1α (SDF-1α) on inflammation (day 4) and proliferation phases (day 8) of repairing tissues in an infected delayed healing and ischemic wound model (IDHIWM) in type 1 diabetic (DM1) rats. DM1 was created in 48 rats and an IDHIWM was made in all of them, and they were distributed into 4 groups. Group1 = control rats with no treatment. Group2 = rats received (10 × 100000 ha-ADS). Group3 = rats exposed to PBM (890 nm, 80 Hz, 3.46 J/cm2). Group4 = rats received both PBM and ha-ADS. On day 8, there were significantly higher neutrophils in the control group than in other groups (p < 0.01). There were substantially higher macrophages in the PBM + ha-ADS group than in other groups on days 4 and 8 (p < 0.001). Granulation tissue volume, on both days 4 and 8, was meaningfully greater in all treatment groups than in the control group (all, p = 0.000). Results of M1 and M2 macrophage counts of repairing tissue in the entire treatment groups were considered preferable to those in the control group (p < 0.05). Regarding stereological and macrophage phenotyping, the results of the PBM + ha-ADS group were better than the ha-ADS and PBM groups. Results of the tested gene expression of repairing tissue on inflammation and proliferation steps in PBM and PBM + ha-ADS groups were meaningfully better than the control and ha-ADS groups (p < 0.05). We showed that PBM, ha-ADS, and PBM plus ha-ADS, hastened the proliferation step of healing in an IDHIWM in rats with DM1 by regulation of the inflammatory reaction, macrophage phenotyping, and augmented granulation tissue formation. In addition PBM and PBM plus ha-ADS protocols hastened and increased mRNA levels of HIF-1α, bFGF, SDF-1α, and VEGF-A. Totally, in terms of stereological and immuno-histological tests, and also gene expression HIF-1α and VEGF-A, the results of PBM + ha-ADS were superior (additive) to PBM, and ha-ADS alone treatments.

Ultrasound-stimulated microbubbles enhancement of fractionated radiation for tumor treatment

BACKGROUND

Radiation therapy (XRT) causes numerous biological changes in tumor microenvironment. Radiation vascular response, due to endothelial disruption, can influence treatment outcomes in a dose-dependent manner. Ultrasound-stimulated microbubbles (USMB) have also been demonstrated to create a vascular response in the tumor microenvironment and enhance tumor response when used in combination with XRT. Single doses of 8-10 Gy are known to induce activation of acid sphingomyelinase (ASMase)-induced ceramide production, causing vascular damage. Destruction of vasculature results in endothelial apoptosis followed by tumor cell death. The effect of tumor response is known to be synergistic by 10-fold higher cell kill observed when USMB is combined with radiation.

METHODS

In this study, we used an USMB approach in combination with conventional low dose fractionated radiation to enhance endothelial cell responses to XRT in human PC3 prostate cancer xenograft model. Mice were divided into untreated, USMB therapy, fractionated XRT, and combined USMB therapy followed by XRT (USMB + XRT) groups. USMB therapy was delivered twice per week in the USMB-alone and combined USMB + XRT treatment groups over four weeks. Radiation treatments were delivered in fractions of 2 Gy/day (total 40 Gy in 20 fractions, BED₁₀ = 48 Gy) in the XRT-alone and combined USMB + XRT groups. The treatment outcome was evaluated using histopathology, power Doppler, and immunohistochemistry assays.

RESULTS

Tumor growth assessment showed that sizes of tumors increased in the control and the single treatment groups over a treatment period of four weeks, but significantly decreased with the combined treatments of USMB + XRT. Immunohistochemical analysis indicated a statistically significant vascular disruption in mice that received treatment involving a full 4-week schedule of combined (USMB + XRT) treatments. A statistically significant increase in vascular disruption was demonstrated through CD68 and trichrome fibrosis staining. Changes in local perfusion assessed using high-frequency power Doppler imaging demonstrated attenuated blood flow in the combined group.

DISCUSSION AND CONCLUSIONS

This work demonstrates the efficacy of using USMB as a radiation sensitizer in a mouse model of human PC3 tumor xenograft. This radiation treatment enhancement modality has the advantage of targeting tumor vasculature with ultrasound stimulation that can be implemented prior to radiation treatment.

Comparative analysis of antigen-presenting cells in gingival tissues in healthy and periodontitis patients

AIMS

Microbial flora of dental plaque trigger innate and adaptive immune responses. The function of antigen-presenting cells (APCs) is to bridge the innate and adaptive immune systems. The human immune system contains three main types of APCs: dendritic cells (DC) (Langerhans cells (LCs) and interstitial DCs, IDCs), macrophages and B lymphocytes. In this study, the distribution and density of all APCs in healthy and inflamed human gingival tissue were comparatively analysed.

METHODS

Research was conducted on gingival biopsy specimens obtained from 55 patients and classified in three groups: healthy gingiva (control group, n=10), moderate periodontal disease (PD) (n=21) and severe PD (n=24). For APCs' identification antibodies raised against CD_1a (for LCs), S₁₀₀ protein (for iDCs), CD₆₈ (for macrophages) and CD₂₀ (for B lymphocytes) were used.

RESULTS

Increased density of IDCs, macrophages and B lymphocytes in lamina propria and reduced density of LCs in the gingival epithelium were found in patients with periodontitis. Simultaneously, it was noticed an increased concentration of macrophages and B cells in the gingival epithelium in patients with PD. No statistically significant difference in the distribution and density of APC was found among patients with moderate and advanced periodontitis.

CONCLUSIONS

It was hypothesised that in the periodontitis the role of antigen presentation was largely taken from LCs by the DCs, macrophages and B cells. These APCs are thought to have less protective and tolerogenic potential than LCs and this is a significant reason for alveolar bone destruction in periodontitis.

Comparative Immunohistochemical Analysis of Macrophage Phenotypes in Cutaneous Sarcoid Granuloma, Suture Granuloma, and Lipogranuloma

ABSTRACT

Granulomas are composed of a heterogeneous population of resident and recruited macrophages according to the type of lesion, extent of injury, and local tissue environment (eg, involved site and interaction with infiltrating lymphocytes). Although macrophage phenotypes in various types of granulomas have been previously described, the experimental conditions varied across studies, precluding a comparative and comprehensive understanding of granulomas. This study was conducted to comparatively analyze the expression of markers of the M1 and M2 phenotypes in macrophages that compose various types of granulomas, including epithelioid lesions, under strict conditions. Surgical specimens of cutaneous sarcoidosis (11 lesions), suture granuloma (10 lesions), and subcutaneous lipogranuloma (12 lesions) were immunohistochemically stained for CD11c, CD206, CD163, and CD10. The expression of these markers in macrophages composing each type of granuloma was scored and statistically analyzed. Granuloma macrophages were mostly immunoreactive for CD11c and CD206 in all the examined cases, although many intermingling CD206-negative cells were observed in 5 cases of lipogranuloma. CD163 and CD10 were diffusely expressed in macrophages composing suture granuloma and lipogranuloma, whereas they were not expressed in epithelioid cells in cutaneous sarcoidosis. Meanwhile, "interstitial" macrophages around epithelioid granulomas revealed moderate to marked CD163 expression in 7 lesions of cutaneous sarcoidosis. These results indicate significant differences of expression of CD163 and CD10 between cutaneous sarcoidosis and suture granuloma/lipogranuloma; CD163 and CD10 are downregulated after the epithelioid transformation of macrophages in cutaneous sarcoidosis.

Prognostic Impact of Tumor Immune Microenvironment and Its Predictive Role in Salivary Gland Cancer

BACKGROUND

Recently, many studies have investigated the role of tumor immune microenvironment (TIME) in carcinogenesis, highlighting its relation to both tumor regression and progression. In particular, the "inflammatory system", made of innate and adaptive immune cells, interacts with cancer cells and their surrounding stroma. In this setting, the aim of this review is to summarize the current literature regarding the TIME of major salivary gland carcinomas (MSGCs), with particular attention on the characteristics and prognostic role of tumor infiltrating lymphocytes (TILs), the mechanisms that lead to TILs exhaustion and the important additional immune infiltrating factors that help SGC progression or remission.

METHODS

A comprehensive literature search was performed concerning published articles on the role of TIME in MSGCs.

RESULTS

In this work we summarize the advancing knowledge on TIME in SGCs by demonstrating the key prognostic and/or predictive value of specific immune features.

CONCLUSION

From the analysis of the current 'status of the art' it clearly emerges a need for precise, unambiguous phenotyping of immune cell populations, as well as a more thorough understanding of the frequencies and interactions of multiple immune cell types inside the TIME and their spatial localization (intratumoral vs. stromal).

Effects of Therapeutic Hypothermia on Macrophages in Mouse Cochlea Explants

Globally, over the next few decades, more than 2.5 billion people will suffer from hearing impairment, including profound hearing loss, and millions could potentially benefit from a cochlea implant. To date, several studies have focused on tissue trauma caused by cochlea implantation. The direct immune reaction in the inner ear after an implantation has not been well studied. Recently, therapeutic hypothermia has been found to positively influence the inflammatory reaction caused by electrode insertion trauma. The present study aimed to evaluate the hypothermic effect on the structure, numbers, function and reactivity of macrophages and microglial cells. Therefore, the distribution and activated forms of macrophages in the cochlea were evaluated in an electrode insertion trauma cochlea culture model in normothermic and mild hypothermic conditions. In 10-day-old mouse cochleae, artificial electrode insertion trauma was inflicted, and then they were cultured for 24 h at 37 °C and 32 °C. The influence of mild hypothermia on macrophages was evaluated using immunostaining of cryosections using antibodies against IBA1, F4/80, CD45 and CD163. A clear influence of mild hypothermia on the distribution of activated and non-activated forms of macrophages and monocytes in the inner ear was observed. Furthermore, these cells were located in the mesenchymal tissue in and around the cochlea, and the activated forms were found in and around the spiral ganglion tissue at 37 °C. Our findings suggest that mild hypothermic treatment has a beneficial effect on immune system activation after electrode insertion trauma.

Biologic Mechanisms of Macrophage Phenotypes Responding to Infection and the Novel Therapies to Moderate Inflammation

Pro-inflammatory and anti-inflammatory types are the main phenotypes of the macrophage, which are commonly notified as M1 and M2, respectively. The alteration of macrophage phenotypes and the progression of inflammation are intimately associated; both phenotypes usually coexist throughout the whole inflammation stage, involving the transduction of intracellular signals and the secretion of extracellular cytokines. This paper aims to address the interaction of macrophages and surrounding cells and tissues with inflammation-related diseases and clarify the crosstalk of signal pathways relevant to the phenotypic metamorphosis of macrophages. On these bases, some novel therapeutic methods are proposed for regulating inflammation through monitoring the transition of macrophage phenotypes so as to prevent the negative effects of antibiotic drugs utilized in the long term in the clinic. This information will be quite beneficial for the diagnosis and treatment of inflammation-related diseases like pneumonia and other disorders involving macrophages.

Spatial Distribution of Macrophage Subtypes Among Rejection Subtypes in Renal Transplant Biopsies by Dual Immunohistochemistry

We performed dual immunohistochemistry for CD163/CD34 and CD68/CD34 in 108 renal transplant indication biopsies to investigate the presence and distribution of macrophages in various renal compartments. All Banff scores and diagnoses were revised according to the Banff 2019 classification. CD163 and CD68 positive cell counts (CD163pos and CD68pos) were evaluated in the interstitium, glomerular mesangium, and, within glomerular and peritubular capillaries. The diagnosis was antibody-mediated rejection (ABMR) in 38 (35.2%), T-cell mediated rejection (TCMR) in 24 (22.2%), mixed rejection in 30 (27.8%), and no rejection in 16 (14.8%). Banff lesion scores t , i , and ti were correlated with both CD163 and CD68 interstitial inflammation scores ( r > 0.30; P < 0.05). Glomerular total CD163pos was correlated to Banff lesion scores g and cg ( r > 0.30; P < 0.05). Glomerular total, mesangial, and intracapillary CD68pos were correlated with g ( r > 0.30; P < 0.05). Both glomerular total and peritubular capillary CD68pos were correlated with peritubular capillaritis ( r > 0.30; P < 0.05). Glomerular CD163pos were significantly higher in ABMR compared with no rejection, in mixed rejection compared with no rejection and TCMR. CD163pos in peritubular capillaries was significantly higher in mixed rejection compared with no rejection. Glomerular CD68pos was significantly higher in ABMR compared with no rejection. CD68pos per peritubular capillary was higher in mixed rejection, ABMR, and TCMR compared with no rejection. In conclusion, compared with CD68 positive macrophages, localization of CD163 positive macrophages in various renal compartments seems to be different among rejection subtypes and their glomerular infiltration seems to be more specific for the presence of ABMR component.

Invasive margin tissue-resident macrophages of high CD163 expression impede responses to T cell-based immunotherapy

BACKGROUND

Primary and secondary resistance is a major hurdle in cancer immunotherapy. Therefore, a better understanding of the underlying mechanisms involved in immunotherapy resistance is of pivotal importance to improve therapy outcome.

METHOD

Here, two mouse models with resistance against therapeutic vaccine-induced tumor regression were studied. Exploration of the tumor microenvironment by high dimensional flow cytometry in combination with therapeutic in vivo settings allowed for the identification of immunological factors driving immunotherapy resistance.

RESULTS

Comparison of the tumor immune infiltrate during early and late regression revealed a change from tumor-rejecting toward tumor-promoting macrophages. In concert, a rapid exhaustion of tumor-infiltrating T cells was observed. Perturbation studies identified a small but discernible CD163^hi macrophage population, with high expression of several tumor-promoting macrophage markers and a functional anti-inflammatory transcriptome profile, but not other macrophages, to be responsible. In-depth analyses revealed that they localize at the tumor invasive margins and are more resistant to Csf1r inhibition when compared with other macrophages. In vivo studies validated the activity of heme oxygenase-1 as an underlying mechanism of immunotherapy resistance. The transcriptomic profile of CD163^hi macrophages is highly similar to a human monocyte/macrophage population, indicating that they represent a target to improve immunotherapy efficacy.

CONCLUSIONS

In this study, a small population of CD163^hi tissue-resident macrophages is identified to be responsible for primary and secondary resistance against T-cell-based immunotherapies. While these CD163^hi M2 macrophages are resistant to Csf1r-targeted therapies, in-depth characterization and identification of the underlying mechanisms driving immunotherapy resistance allows the specific targeting of this subset of macrophages, thereby creating new opportunities for therapeutic intervention with the aim to overcome immunotherapy resistance.

Tumor-associated macrophages and Tregs influence and represent immune cell infiltration of muscle-invasive bladder cancer and predict prognosis

INTRODUCTION AND OBJECTIVE

Muscle-invasive urothelial bladder cancer (MIBC) is associated with limited response rates to systemic therapy, risk of recurrence and death. Tumor infiltrating immune cells have been associated with outcome and response to chemo-and immunotherapy in MIBC. We aimed to profile the immune cells in the tumor microenvironment (TME) to predict prognosis in MIBC and responses to adjuvant chemotherapy.

METHODS

We performed multiplex immunohistochemistry (IHC) profiling and quantification of immune and stromal cells (CD3, CD4, CD8, CD163, FoxP3, PD-1, and CD45, Vimentin, αSMA, PD-L1, Pan-Cytokeratin, Ki67) in 101 patients with MIBC receiving radical cystectomy. We used uni- and multivariate survival analyses to identify cell types predicting prognosis. Samples were subdivided using K-means clustering for Treg and macrophage infiltration resulting in 3 clusters, Cluster 1: Treg high, cluster 2: macrophage high, cluster 3: Treg and macrophage low. Routine CD68 and CD163 IHC were analyzed with QuPath in an extended cohort of 141 MIBC.

RESULTS

High concentrations of macrophages were associated with increased risk of death (HR 10.9, 95% CI 2.8-40.5; p < 0.001) and high concentrations of Tregs were associated with decreased risk of death (HR 0.1, 95% CI 0.01-0.7; p = 0.03) in the multivariate Cox-regression model adjusting for adjuvant chemotherapy, tumor and lymph node stage. Patients in the macrophage rich cluster (2) showed the worst OS with and without adjuvant chemotherapy. The Treg rich cluster (1) showed high levels of effector and proliferating immune cells and had the best survival. Cluster 1 and 2 both were rich in PD-1 and PD-L1 expression on tumor and immune cells.

CONCLUSION

Treg and macrophage concentrations in MIBC are independent predictors of prognosis and are important players in the TME. Standard IHC with CD163 for macrophages is feasible to predict prognosis but validation to use immune-cell infiltration, especially to predict response to systemic therapies, is required.

RNAseq Analysis of FABP4 Knockout Mouse Hippocampal Transcriptome Suggests a Role for WNT/β-Catenin in Preventing Obesity-Induced Cognitive Impairment

Microglial fatty-acid binding protein 4 (FABP4) is a regulator of neuroinflammation. We hypothesized that the link between lipid metabolism and inflammation indicates a role for FABP4 in regulating high fat diet (HFD)-induced cognitive decline. We have previously shown that obese FABP4 knockout mice exhibit decreased neuroinflammation and cognitive decline. FABP4 knockout and wild type mice were fed 60% HFD for 12 weeks starting at 15 weeks old. Hippocampal tissue was dissected and RNA-seq was performed to measure differentially expressed transcripts. Reactome molecular pathway analysis was utilized to examine differentially expressed pathways. Results showed that HFD-fed FABP4 knockout mice have a hippocampal transcriptome consistent with neuroprotection, including associations with decreased proinflammatory signaling, ER stress, apoptosis, and cognitive decline. This is accompanied by an increase in transcripts upregulating neurogenesis, synaptic plasticity, long-term potentiation, and spatial working memory. Pathway analysis revealed that mice lacking FABP4 had changes in metabolic function that support reduction in oxidative stress and inflammation, and improved energy homeostasis and cognitive function. Analysis suggested a role for WNT/β-Catenin signaling in the protection against insulin resistance, alleviating neuroinflammation and cognitive decline. Collectively, our work shows that FABP4 represents a potential target in alleviating HFD-induced neuroinflammation and cognitive decline and suggests a role for WNT/β-Catenin in this protection.

Prone position decreases acute lung inflammation measured by [11C](R)-PK11195 positron emission tomography in experimental acute respiratory distress syndrome

Whether prone positioning (PP) modulates acute lung inflammation by the modulation of biomechanical forces of ventilator-induced lung injuries (VILIs) remains unclear. We aimed to demonstrate that PP decreases acute lung inflammation in animals with experimental acute respiratory distress syndrome (ARDS). Animals were under general anesthesia and protective ventilation (tidal volume 6 mL·kg^-1, PEEP 5 cmH₂O). ARDS was induced by intratracheal instillation of chlorohydric acid. Animals were then randomized to PP, or to supine position (SP). After 4 h, a positron emission tomography (PET) acquisition with [¹¹C](R)-PK11195 was performed coupled with computerized tomography (CT) acquisitions, allowing the CT quantification of VILI-associated parameters. [¹¹C](R)-PK11195 lung uptake was quantified using pharmacokinetic multicompartment models. Analyses were performed on eight lung sections distributed along the antero-posterior dimension. Six animals were randomized to PP, five to SP (median [Formula: see text]/[Formula: see text] [interquartile range]: 164 [102-269] mmHg). The normally aerated compartment was significantly redistributed to the posterior lung regions of animals in PP, compared with SP. Dynamic strain was significantly increased in posterior regions of SP animals, compared with PP. After 4 h, animals in PP had a significantly lower uptake of [¹¹C](R)-PK11195, compared with SP. [¹¹C](R)-PK11195 regional uptake was independently associated with the study group, dynamic strain, tidal hyperinflation, and regional respiratory system compliance in multivariate analysis. In an experimental model of ARDS, 4 h of PP significantly decreased acute lung inflammation assessed with PET. The beneficial impact of PP on acute lung inflammation was consecutive to the combination of decreased biomechanical forces and changes in the respiratory system mechanics.NEW & NOTEWORTHY Prone position decreases acute lung macrophage inflammation quantified in vivo with [¹¹C](R)-PK11195 positron emission tomography in an experimental acute respiratory distress syndrome. Regional macrophage inflammation is maximal in the most anterior and posterior lung section of supine animals, in relation with increased regional tidal strain and hyperinflation, and reduced regional lung compliance.

Assessing the role of tumour-associated macrophage subsets in breast cancer subtypes using digital image analysis

PURPOSE

The number of M1-like and M2-like tumour-associated macrophages (TAMs) and their ratio can play a role in breast cancer development and progression. Early clinical trials using macrophage targeting compounds are currently ongoing. However, the most optimal detection method of M1-like and M2-like macrophage subsets and their clinical relevance in breast cancer is still unclear. We aimed to optimize the assessment of TAM subsets in different breast cancer subtypes, and therefore related TAM subset numbers and ratio to clinicopathological characteristics and clinical outcome.

METHODS

Tissue microarrays of 347 consecutive primary Luminal-A, Luminal-B, HER2-positive and triple-negative tumours of patients with early-stage breast cancer were serially sectioned and immunohistochemically stained for the pan-macrophage marker CD68 and the M2-like macrophage markers CD163, CSF-1R and CD206. TAM numbers were quantified using a digital image analysis algorithm. M1-like macrophage numbers were calculated by subtracting M2-like TAM numbers from the total TAM number.

RESULTS

M2-like markers CD163 and CSF-1R showed a moderate positive association with each other and with CD68 (r ≥ 0.47), but only weakly with CD206 (r ≤ 0.06). CD68 + , CD163 + and CSF-1R + macrophages correlated with tumour grade in Luminal-B tumours (P < 0.001). Total or subset TAM numbers did not correlate with disease outcome in any breast cancer subtype.

CONCLUSION

In conclusion, macrophages and their subsets can be detected by means of a panel of TAM markers and are related to unfavourable clinicopathological characteristics in Luminal-B breast cancer. However, their impact on outcome remains unclear. Preferably, this should be determined in prospective series.

Tumor-associated macrophages mediate gastrointestinal stromal tumor cell metastasis through CXCL2/CXCR2

BACKGROUND

Tumor-associated macrophages (TAMs) are linked with the progression and poor prognosis of multifarious solid tumors, but the regulatory mechanisms involved in gastrointestinal stromal tumors (GIST) remain indistinct. This study intended to delve into the job of TAM-derived chemokines in promoting metastasis in GIST microenvironment.

METHODS

Expression levels of M2-TAM markers and CXCL2 in primary and metastatic tissues of GIST were analyzed by bioinformatics methods, and we analyzed the correlation between CXCL2 and M2-TAM markers. Immunofluorescence was applied to assay CXCL2 and M2-TAM marker protein (CD68 and CD206) expression in tumor tissues. Serum CXCL2 concentration in metastatic and non-metastatic patients was assayed by ELISA. The differentiation of THP-1 cells was tested by flow cytometry. Cell function test was utilized to analyze the viability, invasion and migration of GIST cells. Western blot was used to examine the expression of epithelial-mesenchymal transition (EMT)-related proteins. The mouse liver metastasis model was established, and the effects of CXCL2 and EMT-related genes on metastasis were confirmed by hematoxylin-eosin staining and immunohistochemistry experiments.

RESULTS

Bioinformatics analysis ascertained that M2-TAM marker proteins and chemokine CXCL2 were highly expressed in GIST metastatic tissues, and CXCL2 and TAM were co-located in tumor tissues. Results of in vitro cell function experiments displayed that CXCL2 secreted by M2-TAM promoted the invasion, migration and EMT of GIST tumor cells, and the anti-CXCL2 antibody could block the metastasis promoting effect of CXCL2. Additionally, the silencing of CXCR2 in GIST cells inhibited the metastasis promoting effect of CXCL2. Animal studies further confirmed that CXCL2 promoted liver metastasis of GIST in vivo.

CONCLUSION

This study preliminarily revealed the mechanism of M2-TAM promoting tumor metastasis by secreting CXCL2 in GIST tumor microenvironment, and proffered theoretical reference for the development of immunotherapy strategies targeting M2-TAM.

The imbalance of circulating monocyte subgroups with a higher proportion of the CD14+CD16+CD163+ phenotype in patients with preeclampsia

BACKGROUND

Preeclampsia is a major cause of increased maternal and fetal morbidity and mortality, which is closely related to the abnormal maternal immune response. The skew of decidual macrophage polarization toward M1 phenotype has been proved to promote the pathogenesis of preeclampsia. However, it's not easy to monitor the change of decidual macrophage subtypes. The current study aims to examine the distribution of different circulating monocyte subtypes and analyze whether certain monocyte subtypes act as potential clinical indicators for preeclampsia.

METHODS

A total of 50 pregnant women [mild preeclampsia (n = 20); severe preeclampsia (n = 15); healthy pregnancy (n = 15)] and 15 healthy donors were included in the study. Medical information such as BMI, blood pressure, ALT, creatinine, thrombocyte, etc., were recorded. The frequency of different monocyte subtypes in venous blood were measured by flow cytometry. Serum level of IL-6 was detected using Roche-Hitachi cobas 8000. Serum concentration of inflammatory cytokines (IL-1β, IL-4, IL-10 and TNF-α) were measured by ELISA.

RESULTS

A circulating monocyte subset with both M1 and M2 markers (CD14+CD16+CD163+) was found to occupy an obvious higher proportion in the preeclampsia group than in the normal pregnancy group. The ratio of CD206+/CD206- M2-like monocytes was also increased in the preeclampsia group, and meanwhile, it had statistic difference between the mild- and the severe-preeclampsia group. Furthermore, the serum levels of IL-1β and TNF-α were positively correlated with the frequency of CD14+CD16+CD163+ intermediate monocytes in the preeclampsia group.

CONCLUSIONS

The increased proportion of CD14+C16+CD163+ circulating monocytes and the high ratio of CD206+/CD206- M2-like monocytes may act as potential clinical indicators for preeclampsia, with the superiority of convenience and dynamic monitoring.