Antibody combinations for optimized staining of macrophages in human lung tumours.

The analysis of tumour-associated macrophages (TAMs) has a high potential to predict cancer recurrence and response to immunotherapy. However, the heterogeneity of TAMs poses a challenge for quantitative and qualitative measurements. Here, we critically evaluated by immunohistochemistry and flow cytometry two commonly used pan-macrophage markers (CD14 and CD68) as well as some suggested markers for tumour-promoting M2 macrophages (CD163, CD204, CD206 and CD209) in human non-small cell lung cancer (NSCLC). Tumour, non-cancerous lung tissue and blood were investigated. For immunohistochemistry, CD68 was confirmed to be a useful pan-macrophage marker although careful selection of antibody was found to be critical. The widely used anti-CD68 antibody clone KP-1 stains both macrophages and neutrophils, which is problematic for TAM quantification because lung tumours contain many neutrophils. For TAM counting in tumour sections, we recommend combined labelling of CD68 with a cell membrane marker such as CD14, CD163 or CD206. In flow cytometry, the commonly used combination of CD14 and HLA-DR was found to not be optimal because some TAMs do not express CD14. Instead, combined staining of CD68 and HLA-DR is preferable to gate all TAMs. Concerning macrophage phenotypic markers, the scavenger receptor CD163 was found to be expressed by a substantial fraction (50%-86%) of TAMs with a large patient-to-patient variation. Approximately 50% of TAMs were positive for CD206. Surprisingly, there was no clear overlap between CD163 and CD206 positivity, and three distinct TAM sub-populations were identified in NSCLC tumours: CD163+ CD206+ , CD163+ CD206- and CD163- CD206- . This work should help develop macrophage-based prognostic tools for cancer.

In Vivo MRI of Functionalized Iron Oxide Nanoparticles for Brain Inflammation.

Microglia are intrinsic components of the brain immune system and are activated in many central nervous system disorders. The ability to noninvasively image these cells would provide valuable information for both research and clinical applications. Today, most imaging probes for activated microglia are mainly designed for positron emission tomography (PET) and target translocator proteins that also reside on other cerebral cells. The PET images obtained are not specific for microglia-driven inflammation. Here, we describe a potential PET/MRI multimodal imaging probe that selectively targets the scavenger receptor class A (SR-A) expressed on activated microglia. These sulfated dextran-coated iron oxide (SDIO) nanoparticles are avidly taken up by microglia and appear to be nontoxic when administered intravenously in a mouse model. Intravenous administration of this SDIO demonstrated visualization by T2∗ -weighted MRI of microglia activated by intracerebral administration of tumor necrosis factor alpha (TNF-α). The contrast was significantly enhanced by SDIO, whereas there was little to no contrast change in animals treated with nontargeted nanoparticles or untreated controls. Thus, SR-A targeting represents a promising strategy to image activated microglia in the brain.

Acute exacerbation of IPF has systemic consequences with multiple organ injury, with SRA+ and TNF-α+ cells in the systemic circulation playing central roles in multiple organ injury.

BACKGROUND: The pathophysiologic mechanisms underlying acute exacerbation of idiopathic pulmonary fibrosis (IPF) are not fully understood. Few studies have examined autopsy findings in patients who have died from an acute exacerbation of IPF. The pathologic findings in systemic organs have not been described. METHODS: We retrospectively reviewed the autopsy findings in 12 patients who had died from an acute exacerbation of IPF and two of connective tissue disease- associated interstitial lung disease between 2005 and 2015. We recorded demographic and clinical characteristics, autopsy findings and cytologic findings in peripheral blood. RESULTS: The median age at autopsy was 68 years (range 45-87 years); 11 subjects (78.5 %) were men. High-dose corticosteroid, cyclophosphamide and oxygen therapy had been administered to all patients. Underlying lesions had the usual interstitial pneumonia pattern; diffuse alveolar damage and contraction band necrosis were observed in all cases. Large cells expressing scavenger receptor A (SRA+) had been observed in the systemic circulation of 11 of the 14 cases (78.6 %) before acute exacerbation, and cells expressing tumor necrosis factor-α (TNF-α+) were detected after its diagnosis in nine (64.3 %). Both were detected in all cases at autopsy. There was neutrophil and platelet accumulation predominantly in capillaries, and extensive capillary endothelial cells injury. CONCLUSIONS: Our findings suggest that acute exacerbation of IPF has systemic consequences with multiple organ injury, with SRA+ and TNF-α+ cells in the systemic circulation playing central roles in multiple organ injury.

Low density of CD204-positive M2-type tumor-associated macrophages in Epstein-Barr virus-associated gastric cancer: a clinicopathologic study with digital image analysis.

Recent studies suggest that CD204-positive (CD204(+)) M2-type tumor-associated macrophages (TAMs) are associated with the aggressive behavior of various cancers. However, the clinicopathologic significance of tumor-infiltrating CD204(+) macrophages and their correlation with Epstein-Barr virus (EBV) in gastric cancer is unclear. Tissue microarrays were constructed from 119 surgically resected gastric cancer specimens (86 EBV-negative and 28 EBV-positive cases). After immunohistochemistry of CD204, the density of CD204(+) cells was calculated using image analysis software, and associations between CD204 and clinicopathologic factors including patient survival were examined. High CD204(+) cell density was significantly associated with several adverse prognostic factors, including older age (P = .008), advanced tumor depth (P < .001), lymph node metastasis (P < .001), presence of venous invasion (P < .001), and lymphatic invasion (P = .03). Low CD204(+) cell density was significantly associated with EBV infection. Advanced tumor depth and presence of lymph node metastasis were significantly associated with high CD204(+) cell density in both EBV-positive and EBV-negative subgroups. High CD204(+) cell density was significantly associated with shorter cancer-specific survival (P = .0015). In conclusion, a high density of CD204(+) TAMs was associated with the aggressive behavior and worse survival of gastric cancer. Low density of CD204(+) TAMs was associated with infection of EBV, which may explain the favorable outcome of EBV-associated gastric carcinoma. Our results suggest that a specific immune microenvironment may be associated with the biological behavior of gastric cancer and that EBV-associated gastric carcinoma is distinctive from other gastric carcinomas in tumor immunity.

Initial transient accumulation of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate in rat molars.

INTRODUCTION: M2 (alternatively activated) macrophages are known to participate in wound healing and tissue repair. This study aimed to analyze the temporospatial changes in the distribution and density of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate (MTA) in rat molars to ascertain the role played by M2 macrophages in the healing of MTA-capped pulp tissue. METHODS: The maxillary first molars of 8-week-old Wistar rats were pulpotomized and capped with MTA. After 1-14 days, the teeth were examined after hematoxylin-eosin staining or immunoperoxidase staining of CD68 (a general macrophage marker) and M2 macrophage markers (CD163 and CD204). The density of positively stained cells was enumerated in the surface and inner regions (0-100 µm and 300-400 µm, respectively, from the wound surface). RESULTS: MTA capping initially caused mild inflammatory changes and the formation of a degenerative layer followed by progressive new matrix formation and calcified bridging. At 1-2 days, CD68-, CD163-, and CD204-positive cells started to accumulate beneath the degenerative layer, and the density of these cells was significantly higher in the surface region than in the inner region (P < .05). From 7 days onward, the 3 types of cells displayed an almost normal distribution beneath the newly formed dentinlike matrix. CONCLUSIONS: After the pulpotomy of rat molars with MTA, M2 macrophage-associated molecule-expressing cells transiently accumulated beneath the degenerative layer under the MTA. This suggests that M2 macrophages participate in the initial phases of the healing of MTA-capped pulp tissue.

Keratin pearl degradation in oral squamous cell carcinoma: reciprocal roles of neutrophils and macrophages.

BACKGROUND: We have reported that neutrophilic infiltration was associated with round-shaped dyskeratosis foci, a kind of keratin pearl, of oral carcinoma in situ and that those inflammatory cells are recruited from intra-epithelially entrapped blood vessels. Based on these lines of evidence, we have formulated a hypothesis that keratin pearls are terminally degraded by neutrophils. To confirm this hypothesis, we investigated immunohistochemically stepwise degradation of keratin pearls in oral squamous cell carcinoma (SCC) to clarify any other type scavenger cells in addition to neutrophils are involved in this particular degradation process. METHODS: Neutrophils (neutrophil elastase) and macrophage subpopulations (CD68, CD163 and CD204) were immunohistochemically localized in 30 cases of oral SCC with typical round-shaped keratin pearls. SCC cells were revealed by immunohistochemistry for keratin (K) 17, and blood vessels were demonstrated by CD31. RESULTS: Keratin pearl degradation process was divided into four steps: (i) intact stage: no macrophage infiltration but minimal neutrophils were found in keratin pearls; (ii) neutrophil recruit stage: no macrophage infiltration but focal neutrophilic infiltration within the pearls; (iii) neutrophil predominant stage: dense neutrophil infiltration with minimal macrophages and segregated keratinized cancer cells strongly positive for K17; and (iv) macrophage predominant stage: dense infiltration of CD68-, CD163 (mononuclear)- and CD204 (multinucleated)-positive macrophages engulfing detached keratinized SCC cells. CONCLUSION: Keratin pearl degradation in oral SCC is strictly regulated by two types of scavenger cells: neutrophils, which perform initial tasks, and macrophages, which reciprocally take over from neutrophils the role to finalize the degradation processes.

Prognostic significance of CD204-positive macrophages in upper urinary tract cancer.

BACKGROUND: Evidence suggests that CD204-positive (CD204(+)) tumor-infiltrating macrophages are associated with aggressive behavior of various cancers; however, the clinical, pathological, and prognostic associations of tumor-infiltrating CD204(+) macrophages in urothelial cancer have not been reported. METHODS: A tissue microarray was constructed from the centers and peripheries of 171 upper urinary tract cancers treated with nephroureterectomy. CD204 immunohistochemistry was performed. The density of CD204(+) cells was calculated using image analysis software, and survival analyses were performed using the Kaplan-Meier method and multivariate Cox proportional hazards regression models. RESULTS: High CD204(+) cell density at the centers and peripheries of tumors was significantly associated with several adverse prognostic factors, including sessile architecture, histological high-grade, presence of lymphovascular invasion, concomitant carcinoma in situ, higher tumor stage, and lymph node metastasis. High CD204(+) cell density was significantly associated with shorter metastasis-free and cancer-specific survival (log-rank p < 0.001) and shorter metastasis-free survival in multivariate analysis. CONCLUSIONS: A high density of tumor-infiltrating CD204(+) macrophages was associated with aggressive behavior of upper urinary tract cancer. Our results suggest that a specific immune microenvironment may be associated with the biological behavior of urothelial cancer and that CD204 may serve as a novel prognostic biomarker for these tumors.

Macrophage infiltration and its prognostic relevance in clear cell renal cell carcinoma.

Most malignant tumors evidence infiltration of many macrophages. In this study, we investigated an anti-inflammatory macrophage phenotype (M2) in clear cell renal cell carcinoma (RCC) using CD163 and CD204 as markers. Immunostaining showed a correlation between the number of CD163(+) cells and age, sex, nuclear grade, and TNM classification. High infiltration of CD163(+) cells was significantly associated with poor clinical prognosis in univariate analysis but not in multivariate analysis. We also carried out in vitro studies to examine cell-cell interactions between macrophages and cancer cells. Culture supernatants from RCC cell lines induced polarization of macrophages toward the M2 phenotype. Coculture of macrophages with cancer cells significantly induced activation of signal transducers and activators of transcription-3 (Stat3) in the cancer cells. Direct coculture of RCC cells with macrophages led to stronger activation of Stat3 in the cancer cells than did indirect coculture using Transwell chamber dishes. Because RCC cells expressed membrane-type macrophage colony-stimulating factor (mM-CSF) on the cell surface, we suggested that this mM-CSF plays an important role in direct cell-cell interactions. Stat3 activation in cancer cells that was induced by coculture with macrophages was suppressed by downregulation of the M-CSF receptor (M-CSFR) in macrophages and by an inhibitor of M-CSFR. In conclusion, investigation of CD163(+) tumor-associated macrophages would be useful for assessment of the clinical prognosis of patients with ccRCC. Cell-cell interactions mediated by mM-CSF and M-CSFR binding could contribute to cancer cell activation.

Alteration in the phenotype of macrophages in the repair of renal interstitial fibrosis in mice.

AIM: Renal interstitial fibrosis is the final common pathway determining long-term prognosis of chronic kidney diseases, but its repair process is scarcely understood. Because recent reports indicate that M2 macrophages play important roles in the repair of various tissues, special attention was paid to the phenotypes of infiltrating macrophages in the present study when the histological changes occurring in mouse kidneys after the release of unilateral ureteral obstruction (UUO) inducing renal fibrosis were analyzed. METHODS: The left ureter of male mice was obstructed for 10 days by using a vascular clamp, and that kidney was removed for analysis either on the day when the clamp was removed or after the kidney had been allowed to recover for 3, 7 or 21 days. RESULTS: Interstitial fibrosis assessed by picrosirius red staining decreased with time after the release, and this decrease was paralleled by a decrease in the interstitial area positive for α-smooth muscle actin. Macrophage infiltration assessed by F4/80 staining also significantly decreased from day 3. In contrast, real-time reverse transcription polymerase chain reaction revealed that the ratios of mRNA for the macrophage scavenger receptor (CD204) and the mannose receptor (CD206), both of which are preferentially expressed on M2 macrophages, to CD68 (a general macrophage marker) were significantly greater on day 7 than on day 0 in the UUO-released mice. CONCLUSION: Although the total number of infiltrating myofibroblasts and macrophages decreased after UUO release, the ratios of macrophages expressing CD204 and CD206 increased, suggesting that M2 macrophages play an important role in the repair of renal fibrosis.

Decreased infiltration of macrophage scavenger receptor-positive cells in initial negative biopsy specimens is correlated with positive repeat biopsies of the prostate.

Macrophage scavenger receptor (MSR)-positive inflammatory cells and tumor-associated macrophages (TAMs) have been reported to regulate the growth of various cancers. In this study, the infiltration of MSR-positive cells and TAMs was analyzed to predict the outcome of repeat biopsy in men diagnosed as having no malignancy at the first prostate biopsy. Repeat biopsy of the prostate was carried out in 92 patients who were diagnosed as having no malignancy at the first biopsy. Of these, 30 patients (32.6%) were positive for prostate cancer at the repeat biopsy. Tumor-associated macrophages and MSR-positive cells were immunohistochemically stained with mAbs CD68 and CD204, respectively. Six ocular measuring fields were chosen randomly under a microscope at x400 power in the initial negative biopsy specimens, and the mean TAM and MSR counts for each case were determined. No difference in TAM count was found between the cases with or without prostate cancer. By contrast, the MSR count in patients with cancer was significantly lower than that in patients without cancer at the repeat biopsy (P < 0.001). Logistic regression analysis indicated that the MSR count at first biopsy is a significantly better predictive factor for positive repeat biopsy than PSA velocity, interval between first and repeat biopsies, or TAM count. Decreased infiltration of MSR-positive cells in negative first biopsy specimens was correlated with positive findings in the repeat biopsy. The MSR count might be a good indicator for avoiding unnecessary repeat biopsies.

Recruitment of immune cells across atrial endocardium in human atrial fibrillation.

BACKGROUND: Although clinical studies have suggested a link between inflammation markers and atrial fibrillation (AF), it is still unclear whether local immunologic responses actually exist in human atria during AF. METHODS AND RESULTS: To address this point, human left appendages were obtained from 16 patients who underwent cardiac surgery (5 with sinus rhythm (SR) and 11 with AF) and subjected to immunohistochemical analysis. In all the AF specimens, adhesion and migration of CD45-reactive cells were consistently observed predominantly in the atrial endo- and subendomyocardium and more prominently than in SR. Most of them were immunologically active CD68-positive macrophages, whereas CD3-positive T cells infiltrated to a lesser extent. Scavenger-receptor A staining revealed maturation of macrophages not in the endocardium but in the midmyocardium, a gradient from endo- to midmyocardium. In the endocardium, along with adhesion molecules (intracellular adhesion molecule-1 and vascular cell adhesion molecule-1), a chemotactic protein-1, which facilitates the recruitment, was more abundantly expressed in AF than in SR. Cytokines including transforming growth factor-beta and interleukin-6 were frequently expressed by these macrophages. CONCLUSIONS: These observations collectively imply active adhesion and recruitment of macrophages across the endocardium in human fibrillating atria, thereby supporting the concept of local immunologic inflammatory responses around the atrial endocardium of AF.

Possible involvement of the M2 anti-inflammatory macrophage phenotype in growth of human gliomas.

Within tumours, many non-neoplastic cells such as fibroblasts, endothelial cells, and macrophages assist tumour growth by producing various growth factors and pro-angiogenic cytokines. Various tumour-derived molecules drive tumour-associated macrophages towards an anti-inflammatory phenotype (M2) and thus promoting tumour growth. Here we investigated microglia/macrophage differentiation in glioma tissues by means of immunostaining of paraffin-embedded glioma samples. The number of microglia/macrophages with positive staining for CD163 and CD204, which are believed to be markers for M2 macrophages, was correlated with the histological grade of the gliomas. The ratio of M2 macrophages in the tumour-associated microglia/macrophages was also associated with the histological grade. Culture supernatant from the glioma cell line can stimulate macrophages to develop into the M2 phenotype in vitro. Macrophage colony-stimulating factor (M-CSF), which strongly induces M2 polarization of macrophages, was significantly correlated with histological malignancy and with the proportion of M2 microglia/macrophages in vivo. In addition, the proportion of M2 microglia/macrophages and M-CSF expression in tumour cells correlated well with proliferation of glioblastoma cells. These results suggest that tumour-derived M-CSF induces a shift of microglia/macrophages towards the M2 phenotype, which influences tumour growth. Evaluation of the proportion of M2 microglia/macrophages and M-CSF expression in tumour tissue would be useful for assessment of microglia/macrophage proliferative activity and the prognosis of patients with gliomas.

Analysis of the RNASEL/HPC1, and macrophage scavenger receptor 1 in Asian-Indian advanced prostate cancer.

OBJECTIVES: Prostate cancer (PC) varies widely by geographic location and ethnicity. American men have a high PC risk but most have localized disease. In contrast, Asian Indians have a low PC risk but most are diagnosed with metastatic disease. Epidemiological and genetic data suggest an important role of genetic susceptibility in PC. Most studies were performed in whites. Substantially less is known about gene variation-associated PC in low-risk populations. The objective of this study was to investigate the role of RNASEL and MSR1 in Asian-Indian men with advanced PC. METHODS: We genotyped DNA samples obtained from 113 cases and 245 age-matched controls (Northern India). RESULTS: For RNASEL, we identified 8 variants (7 novel and 1 previously published, D541E), including 4 exonic, 3 intronic, and 1 change in the 3'-noncoding region. Of these, we detected a novel 4-bp truncation mutation (Val51ArgfsX2) in 2 controls. For MSR1, we identified 4 novel variants (2 intronic and 2 exonic) and 2 previously reported variants (P275A and promoter -4,637 A>G). We also genotyped 3 common MSR1 variations (promoter -14,742 A>G, IVS5-59 C>A, and IVS7 delinsTTA). We found no associations among any of the sequence variations and PC. Three major haplotypes account for most of all MSR1 haplotypes in Asian Indians. Haplotype frequencies were not significantly different between cases and controls. CONCLUSIONS: Our results do not support a role for RNASEL, or MSR1 mutations in advanced Asian-Indian PC. This study warrants additional investigations of these genes in etiology particularly among individuals from diverse ethnic and geographic groups.