Number Of Fibrocytes Research Articles

Pravastatin prevents colitis-associated carcinogenesis by reducing CX3CR1high M2-like fibrocyte counts in the inflamed colon

Colorectal cancer (CRC) resulting from chronic inflammation is a crucial issue in patients with inflammatory bowel disease (IBD). Although many reports established that intestinal resident CX3CR1high macrophages play an essential role in suppressing intestinal inflammation, their function in colitis-related CRC remains unclear. In this study, we found that colonic CX3CR1high macrophages, which were positive for MHC-II, F4/80 and CD319, promoted colitis-associated CRC. They highly expressed Col1a1, Tgfb, II10, and II4, and were considered to be fibrocytes with an immunosuppressive M2-like phenotype. CX3CR1 deficiency led to reductions in the absolute numbers of CX3CR1high fibrocytes through increased apoptosis, thereby preventing the development of colitis-associated CRC. We next focused statins as drugs targeting CX3CR1high fibrocytes. Statins have been actively discussed for patients with IBD and reported to suppress the CX3CL1/CX3CR1 axis. Statin treatment after azoxymethane/dextran sulfate sodium-induced inflammation reduced CX3CR1high fibrocyte counts and suppressed colitis-associated CRC. Therefore, CX3CR1high fibrocytes represent a potential target for carcinogenesis-preventing therapy, and statins could be safe therapeutic candidates for IBD.

Effects of Active Chronic Cigarette-Smoke Exposure on Circulating Fibrocytes

PurposeThis study aimed to evaluate the hypothesis that active smoking impacts upon mediators and abundance of circulating fibrocyte cells in smoking-related disease characterised by fibrosis.MethodsFlow cytometry and enzyme-linked immunosorbent assays were used to investigate blood from five patient groups: healthy never-smokers, healthy current smokers, stable chronic obstructive pulmonary disease (COPD) active smokers, idiopathic pulmonary fibrosis (IPF) never-smokers, and IPF active smokers.ResultsA significant inverse dose–response relationship was observed in healthy smokers among cumulative smoking burden (pack-years) and fibrocyte abundance (p = 0.006, r = −0.86). Among serum profibrotic fibrocyte chemokines measured, CCL18 rose significantly alongside fibrocyte numbers in all five subject groups, while having an inverse dose–response relationship with pack-year burden in healthy smokers (p = 0.003, r = −0.89). In IPF, CCL2 rose in direct proportion to fibrocyte abundance irrespective of smoking status but had lower serum levels in those currently smoking (p = < 0.001). For the study population, CXCL12 was decreased in pooled current smokers versus never-smokers (p = 0.03).ConclusionThe suppressive effect of current, as distinct from former, chronic smoking on circulating fibrocyte abundance in healthy smokers, and modulation of regulatory chemokine levels by active smoking may have implications for future studies of fibrocytes in smoking-related lung diseases as a potential confounding variable.

Low-level LASER therapy accelerates fungal lesions cicatrization by increasing the production of Th1 and Th2 cytokines.

Our study focused on the resolution of lesions caused by fungal infection using a subcutaneous air pouch model of infection. We evaluated cell profile and cytokines, fungi viability, and the presence of fibroblasts and fibrocytes at the site of infection. Inoculation of P. brasiliensis (Pb) was performed using a subcutaneous air pouch model and the LLLT irradiation was performed on alternate days on the rear paws of mice for 10days, after which the cells from the air pouch were collected and analyzed. In animals irradiated with LLLT, the influx of cells to the air pouch was reduced, but they were more activated and produced pro-inflammatory (IL-12, IL-17 and TNF-α) and neutrophil (PMN) activating cytokines (IL-8, GM-CSF and γ-IFN). A better resolution of the infection, evidenced by the reduction in the number of viable fungi with preserved morphology in the air pouch, and an increase in the number of fibrocytes, indicating a healing profile were also observed. LLLT decreased the influx of PMN, but those presents were highly activated, with increased fungicidal activity. LLLT irradiation also resulted in earlier cicatrization at the site of infection, leading to a better outcome of the infection. These data are favorable to the use of LLLT as a complementary therapy in PCM.

Efficacy of Sauropus androgynous Leaves Extract Gel on Burn Wound Healing in Albino Rats

Burns not only damage skin locally but generally affect the body system and have been related as the secondary cause of death. Burns can be effectively treated with a topical drug to prevent chronic inflammation. Burn wound healing is really important for ensuring overall health and well-being. This study aimed to determine the effect of Sauropus androgynous leaves extract gel on the number of fibroblasts, fibrocytes, and collagen density on burn wound healing in albino rats. A total of 50 male albino rats were randomly divided into five groups i.e. (C-) was normal skin, (C+) was skin burn treated with placebo, (T1) was skin burn treated with 2.5% of S. androgynous leaves extract gel, (T2) was skin burn treated with 5% of S. androgynous leaves extract gel, and (T3) was skin burn treated with 10% of S. androgynous leaves extract the gel. The amount of 25 albino rats’ skin samples were collected on the 8th day, and the remaining samples were collected on the 15th day. The results showed that 10% of S. androgynous leaves extract gel improved faster, as indicated by the increased number of fibroblasts, fibrocytes, and collagen density. This study can be concluded that 10% of S. androgynous leaves extract gel was the effective dosage to increase the number of fibroblasts, fibrocytes, and collagen density in burn wound healing.

Alterations in the mammary gland and tumor microenvironment of formerly obese mice

BackgroundObesity is a risk factor for breast cancer, and women with obesity that develop breast cancer have a worsened prognosis. Within the mammary gland, obesity causes chronic, macrophage-driven inflammation and adipose tissue fibrosis. Weight loss is a recommended intervention to resolve obesity, but the impact of weight loss on the mammary gland microenvironment and in tumors has not been well identified.MethodsTo examine the effects of weight loss following obesity, mice were fed a high-fat diet for 16 weeks to induce obesity, then switched to a low-fat diet for 6 weeks. We examined changes in immune cells, including fibrocytes, which are myeloid lineage cells that have attributes of both macrophages and myofibroblasts, and collagen deposition within the mammary glands of non-tumor-bearing mice and within the tumors of mice that were transplanted with estrogen receptor alpha positive TC2 tumor cells. ResultsIn formerly obese mice, we observed reduced numbers of crown-like structures and fibrocytes in mammary glands, while collagen deposition was not resolved with weight loss. Following transplant of TC2 tumor cells into the mammary glands of lean, obese, and formerly obese mice, diminished collagen deposition and cancer-associated fibroblasts were observed in tumors from formerly obese mice compared to obese mice. Within tumors of obese mice, increased myeloid-derived suppressor cells and diminished CD8+ T cells were identified, while the microenvironment of tumors of formerly obese mice were more similar to tumors from lean mice. When TC2 tumor cells were mixed with CD11b+CD34+ myeloid progenitor cells, which are the cells of origin for fibrocytes, and transplanted into mammary glands of lean and obese mice, collagen deposition within the tumors of both lean and obese was significantly greater than when tumor cells were mixed with CD11b+CD34− monocytes or total CD45+ immune cells. ConclusionsOverall, these studies demonstrate that weight loss resolved some of the microenvironmental conditions within the mammary gland that may contribute to tumor progression. Additionally, fibrocytes may contribute to early collagen deposition in mammary tumors of obese mice leading to the growth of desmoplastic tumors.

Neoplastic Monocyte-Derived Fibrocytes Induce Bone Marrow Fibrosis in Patients with Primary Myelofibrosis

Progressive bone marrow (BM) fibrosis is a defining feature of primary myelofibrosis (PMF). The extent of BM fibrosis has been closely associated with the clinical manifestations of advanced disease, including anemia and thrombocytopenia, rendering it an important prognostic indicator. Mesenchymal stromal cells (MSCs) have long been regarded as the exclusive inducer of BM fibrosis. However, using xenograft and transgenic animal models, we and other investigators demonstrated that neoplastic monocyte-derived fibrocytes independently contribute to the induction of BM fibrosis in PMF. Notably, our data revealed that PMF fibrocytes but not MSCs, carry pro-fibrotic signaling pathways that are absent in healthy individuals' fibrocytes or MSCs. Despite these findings, the precise contribution of BM fibrocytes and MSCs to the induction of BM fibrosis in patients with PMF remains elusive. To determine which of two subsets of collagen-producing cells are the main contributors to the induction of BM fibrosis in PMF, we analyzed BM biopsies of patients with PMF and assessed whether their distribution spatially correlated with areas of fibrosis. We analyzed formalin-fixed paraffin-embedded BM trephine biopsies obtained from previously untreated patients with PMF (n = 85) and age-matched healthy donors (n = 6). Using a 7-plexed fluorescence immunohistochemistry (IHC) in conjunction with hematoxylin/eosin, Masson's trichrome, and Gomorri's silver stains we analyzed those BM biopsy specimens. To ensure comprehensive assessment, we imaged serial whole-tissue sections from each patient at 400x resolution, meticulously aligning and carefully correcting for bone trabeculae and any artifacts. To quantitate the spatial distribution of individual cells, collagen fibers, and reticulin fibers, we developed a set of analytical algorithms based on a U-Net neural network in Visiopharm software. Our analysis revealed a 6-fold higher density of fibrocytes, defined as CD45 +/CD68 +/procollagen type I + cells, in the BM of patients with PMF ( P=0.0003) compared to normal controls. By contrast, the number of MSCs, defined as CD45 -/CD90 +/CD105 + cells, in the PMF BM was not different from the number of MSCs in normal BM. After dividing the area of each BM biopsy into a 100 μm regular hexagonal grid, the observed spatial distribution of fibrocytes strongly and positively correlated with the areas covered by reticulin and collagen fibers ( P&amp;lt;0.0001 in both). Furthermore, spatial analysis showed that increased densities of fibrocytes were associated with an increased number of fibrotic cellular zones in the BM tissue of PMF patients. To investigate the clonality of PMF BM fibrocytes, we conducted DNA in situ hybridization (ISH) analysis, employing two sets of locus-specific probe pairs. The DNA-ISH analysis provided valuable insights, revealing that fibrocytes obtained from PMF patients with trisomy 9 or 20q deletion carried the same corresponding cytogenetic abnormalities, indicating that PMF fibrocytes indeed originate from the neoplastic PMF clone. Because increased peripheral blood monocyte counts, commonly detected in patients with PMF, are associated with a poor prognosis, we sought to determine the potential correlation between BM fibrocyte and circulating monocyte counts. As expected, we found a significant positive correlation between BM fibrocyte counts and the percentage of circulating monocytes ( P=0.001). Moreover, we also found that fibrocyte numbers correlated with the levels of the plasma cytokines pentraxin 3, known to induce the differentiation of monocytes into fibrocytes, and matrix metalloproteinase 2, as assessed by using magnetic immunoassay, suggesting that neoplastic fibrocytes induce BM fibrosis in PMF and that fibrocyte quantification could serve as a valuable indicator of disease severity and prognosis. Taken together, our quantitative imaging analysis of BM biopsy tissue from treatment naïve PMF patients revealed that neoplastic fibrocytes, rather than MSCs, are the main contributors to the induction of BM fibrosis in PMF. Our findings underscore the importance of BM fibrocytes in the pathogenesis of PMF and warrant further investigation to identify novel therapeutic agents that will either inhibit fibrocyte differentiation or block their pro-fibrotic function.

Old age promotes retinal fibrosis in choroidal neovascularization through circulating fibrocytes and profibrotic macrophages

BackgroundRetinal fibrosis affects 40–70% of neovascular age-related macular degeneration patients. This study investigated the effect of ageing on subretinal fibrosis secondary to choroidal neovascularization and the mechanism of action.MethodsSubretinal fibrosis was induced in young (2.5-month) and aged (15–16-month) C57BL/6J mice using the two-stage laser protocol. Five and 30 days later, eyes were collected and stained for CD45 and collagen-1 and observed by confocal microscopy. Fibrocytes (CD45+collagen-1+) were detected in the bone marrow (BM), blood and fibrotic lesions by flow cytometry and confocal microscopy, respectively. BM-derived macrophages (BMDMs) were cultured from young and aged mice with or without TGF-β1 (10 ng/mL) treatment. The expression of mesenchymal marker αSMA (Acta2), fibronectin (Fn1) and collagen-1 (Col1a1) was examined by qPCR and immunocytochemistry, whereas cytokine/chemokine production was measured using the Luminex multiplex cytokine assay. BM were transplanted from 22-month (Ly5.2) aged mice into 2.5-month (Ly5.1) young mice and vice versa. Six weeks later, subretinal fibrosis was induced in recipient mice and eyes were collected for evaluation of fibrotic lesion size.ResultsUnder normal conditions, the number of circulating fibrocytes (CD45+collagen-1+) and the expression levels of Tgfb1, Col1a1, Acta2 and Fn1 in BMDMs were significantly higher in aged mice compared to young mice. Induction of subretinal fibrosis significantly increased the number of circulating fibrocytes, enhanced the expression of Col1a1, Acta2 and Fn1 and the production of soluble urokinase plasminogen activator surface receptor (suPAR) but decreased the production of CXCL10 in BMDMs. BMDMs from aged subretinal fibrosis mice produced significantly higher levels of VEGF, angiopoietin-2 and osteopontin than cells from young subretinal fibrosis mice. The subretinal fibrotic lesion in 15–16-month aged mice was 62% larger than that in 2.5-month young mice. The lesion in aged mice contained a significantly higher number of fibrocytes compared to that in young mice. The number of circulating fibrocytes positively correlated with the size of subretinal fibrotic lesion. Transplantation of BM from aged mice significantly increased subretinal fibrosis in young mice.ConclusionsA retina–BM–blood–retina pathway of fibrocyte/macrophage recruitment exists during retinal injury. Ageing promotes subretinal fibrosis through higher numbers of circulating fibrocytes and profibrotic potential of BM-derived macrophages.

Possibilities of regulating the reaction of tissues of the implantation area with pyrimidine preparations after prosthetic repair of the hernia ring in the experiment

Purpose of the study. Study of the possibilities of pharmacological regulation of local and systemic inflammatory response, stimulation of reparative regeneration in prosthetic repair of abdominal wall hernias.Materials and methods. The experiment was carried out on 92 rats of both sexes of a pure line, divided into 4 groups. Group I (control) received only 1 ml of 0.9 % sodium chloride solution. Group II – hydroxyethyldimethyldihydropyrimidine 21 mg/day. Group III – potassium orotate 10.5 mg/day. Group IV – methyluracil 14 mg/day. Under anesthesia a mesh implant 4 × 2 cm was placed in the layer between the hypodermis and the superficial fascia. Animals were withdrawn from the experiment on days 5 (n = 52) and 14 days (n = 40). The site of implantation for histomorphometric studies captured the dermis, hypodermis, implant layer, fascia, and muscle. The preparation and staining of the preparations were carried out with hematoxylin-eosin and by Mallory.Results. 1. On the 5th day after the operation group II (hydroxyethyldimethyldihydropyrimidine) was characterized by pronounced neovasculogenesis (p = 0.002, U-test) and more active processes of formation and maturation of connective tissue (p = 0.024, U-test) with a low immune response to a foreign body (p = 0.044, U- test). III (potassium orotate) and IV groups (methyluracil) were characterized by a pronounced decrease in the inflammatory response with a simultaneous increase in tissue edema (p &lt; 0.001, U-test), slowing down the formation and maturation of connective tissue (p = 0.016, U-test). 2. On the 14th day after the operation, group II (hydroxyethyldimethyldihydropyrimidine) was characterized an increase in the area of neovasculogenesis by 208.0 % (p &lt; 0.001, U -criterion), a decrease in the volume of fluid accumulations by 63.4 % (p &lt; 0.001, U-criterion), an increase in the processes of formation and maturation of connective tissue, mainly due to an increase in the number of fibrocytes by 333.3 % (p &lt; 0.001, U-criterion). The parameters of the immune response to a foreign body had significant differences (p &lt; 0.001, U-test).Conclusion. The use of potassium orotate and methyluracil reduces the inflammatory response in the tissues of the implantation area, however, it is associated with the appearance of liquid components and with a decrease in the formation of connective tissue cells. The use of hydroxyethyldimethyldihydropyrimidine is devoid of the above disadvantages, it is characterized by the predominance of regeneration and neovasculogenesis processes, which allows it to be used as a pharmacological support drug for prosthetic hernioplasty.

Characterization of Circulating Fibrocytes in People Living with HIV on Stable Antiretroviral Therapy.

Highly effective combination antiretroviral therapy has reduced HIV infection to a manageable chronic disease, shifting the clinical landscape toward management of noninfectious comorbidities in people living with HIV (PLWH). These comorbidities are diverse, generally associated with accelerated aging, and present within multiple organ systems. Mechanistically, immune dysregulation and chronic inflammation, both of which persist in PLWH with well-controlled virally suppressive HIV infection, are suggested to create and exacerbate noninfectious comorbidity development. Persistent inflammation often leads to fibrosis, which is the common end point pathologic feature associated with most comorbidities. Fibrocytes are bone marrow-derived fibroblast-like cells, which emerged as key effector cells in tissue repair and pathologic fibrotic diseases. Despite their relevance to fibrosis, the circulating fibrocyte concentration in PLWH remains poorly characterized, and an understanding of their functional role in chronic HIV is limited. In this study, utilizing PBMCs from a cross-sectional adult HIV cohort study with matched uninfected controls (HIV-), we aimed to identify and compare circulating fibrocytes in blood. Both the percentage and number of fibrocytes and α-smooth muscle actin+ fibrocytes in circulation did not differ between the HIV+ and HIV- groups. However, circulating fibrocyte levels were significantly associated with increasing age in both the HIV+ and HIV- groups (the percentage and number; r = 0.575, p ≤ 0.0001 and r = 0.558, p ≤ 0.0001, respectively). Our study demonstrates that circulating fibrocyte levels and their fibroblast-like phenotype defined as collagen I and α-smooth muscle actin+ expression are comparable between, and strongly associated with, age irrespective of HIV status.

Analysis of the chemotactic factors for tumor-infiltrating fibrocytes and their prognostic significances in lung cancer.

Fibrocytes, which are bone marrow-derived collagen-producing cells, have been reported to be involved in pathogenesis of pulmonary fibrosis. Our previous study reported that tumor-infiltrating fibrocytes play a role in tumor progression and drug resistance in lung cancer. The present study therefore examined chemotactic factors for fibrocytes in tissues of non-small cell lung cancer (NSCLC) and their prognostic significance. Surgically resected tumor tissues were examined for the expression of chemotactic factors, including C-X-C motif chemokine 12 (CXCL12), CCL2, platelet-derived growth factor (PDGF)-AA and PDGF-BB, as well as tumor-infiltrating fibrocytes by immunostaining. The chemotactic ability of fibrocytes in response to each factor was evaluated using a migration assay by counting the migrated cells microscopically, and expression of receptors for chemotactic factors were analyzed by flow cytometry. The expression of CXCL12, but not CCL2, PDGF-AA, or PDGF-BB, was associated with the number of tumor-infiltrating fibrocytes in lung adenocarcinoma (LUAD), but not lung squamous cell carcinoma (LUSQ). In addition, patients with an increased expression of CXCL12 in LUAD but not LUSQ showed a significantly poorer prognosis compared with those with a decreased expression. However, the expression of CCL2, PDGF-AA and PDGF-BB was not correlated with the prognosis of patients with NSCLC. The number of fibrocytes was associated with a poor prognosis in LUAD. Fibrocytes derived from the peripheral blood of healthy subjects as well as patients with lung cancer expressed higher levels of CXCR4 compared with CCR2, PDGF and receptor-α and receptor-β. Overall, these results suggested that targeting tumor-infiltrating fibrocytes via the CXCL12/CXCR4 axis may be a useful strategy for controlling the progression of NSCLC, particularly LUAD.

The Effectiveness of Intradermal Suture Technique on Hypertrophic Scar Prevention in Rats

Introduction : Hypertrophic scarring is a complication that occurs in post-surgical wounds. There are many ways to prevent scarring, but there have been no satisfactory methods yet. Moreover, no studies investigated the effectiveness of intradermal sutures. Polypropylene thread can be used to repair a scar after surgery. This study aimed to prove the effectiveness of intradermal sutures using polypropylene thread on surgical scar quality.Method : The study was conducted using a randomized, controlled trial, and post-test only with 20 rats (Rattus norvegicus) as animal subjects. The wounds were made on the back, approximately 6 mm x 2 cm. Then, the rats were divided into two groups: a control group without intradermal sutures (K) and treatment group with intradermal sutures (I). Histopathological examination using Hematoxylin and Eosin (H&amp;E) staining was used to identify the fibroblast number on the 21st day. The fibrocytes number were also observed on the 12th week and the Vancouver Scar Scale (VSS) was used to assess the scar quality.Result : The number of fibroblasts and fibrocytes in the control group (K) was significantly smaller (53.60 ± 14.571; 3.20 ± 0.447) than the treatment (I) (243.20 ± 75.334; 171.40 ± 13.221). The VSS value was significantly greater in the control than the treatment.Conclusion: The intradermal sutures using polypropylene thread produced a better-quality scar after surgery compared to wounds without intradermal sutures.

Oxygen Desaturation Is Associated With Fibrocyte Activation via Epidermal Growth Factor Receptor/Hypoxia-Inducible Factor-1α Axis in Chronic Obstructive Pulmonary Disease.

Fibrocytes are bloodborne mesenchymal progenitors which accumulate and differentiate at the disease site. We investigated whether hypoxemia activates fibrocytes, accelerating airflow limitation and exercise intolerance in chronic obstructive pulmonary disease (COPD) patients. Flow cytometry was used to determine collagen I+/CD45+ fibrocytes and α-smooth muscle actin+ differentiating fibrocytes within peripheral blood and cultured cells, as well as the expression of CXC chemokine receptor 4 (CXCR4), epidermal growth factor receptor (EGFR), connective tissue growth factor (CTGF) and hypoxia-inducible factor (HIF)-1α. Fibrocytes in lung specimens were identified by confocal microscopy. Compared to non-desaturators, COPD desaturators (peripheral blood oxygen saturation ≤88% during exercise) had greater number of fibrocytes in peripheral blood and lung specimens, paralleled with faster yearly lung function decline and a 6-minute walk distance. Fibrocytes from desaturators expressed more EGFR, CXCR4, CTGF, and HIF-1α, with a higher capacity of proliferation and myofibroblastic differentiation. Hypoxia (5% oxygen) increased the expression of EGFR, CXCR4, CTGF, and HIF-1α, the number and differentiation in fibrocytes. These effects were attenuated by EGFR inhibitor gefitinib, HIF-1α gene silencing, and anti-CTGF antibody. These data elucidate that hypoxemia triggers fibrocyte activation through the EGFR/HIF-1α axis, aggravating airflow obstruction in COPD.

Topical Administration Effect of Sargassum duplicatum and Garcinia mangostana Extracts Combination on Open Wound Healing Process in Diabetic Mice.

This research aimed to determine the topical administration effect of the combination of Sargassum duplicatum and Garcinia mangostana extracts to ameliorate diabetic open wound healing. The study used 24 adult males of Mus musculus (BALB/c strain, 3–4 months, 30–40 g). They were divided into normal control groups (KN) and diabetic groups. The diabetic group was streptozotocin-induced and divided further into three treatment groups: the diabetic control group (KD), the S. duplicatum treatment group (PA), and the combination of S. duplicatum and G. mangostana treatment group (PAM). The dose of treatment was 50 mg/kg of body weight. Each group was divided into three treatment durations, which were 3 days, 7 days, and 14 days. The wound healing process was determined by wound width, the number of neutrophils, macrophages, fibroblasts, fibrocytes, and collagen density. Histological observation showed that the topical administration of combination extracts increased the re-epithelialization of the wounded area, fibroblasts, fibrocytes, and collagen synthesis. The topical administration of combination extracts also decreased the number of neutrophils and macrophages. This study concluded that the topical administration of the combination of S. duplicatum and G. mangostana extracts improved the open wound healing process in diabetic mice.

First molecular description of Macracanthorhynchus hirudinaceus in wild boars from Italy with pathomorphological and epidemiological insights.

Macracanthorhynchus hirudinaceus is a zoonotic parasite affecting suids worldwide which are the definitive hosts for this helminth species. Macracanthorhynchus hirudinaceus is of significant economic and management concern due to its pathogenicity, causing intestinal obstruction and perforation in the definitive hosts. Current study is the preliminary investigation from Sardinia, Italy, reporting the pathomorphological findings and molecular characterization of M. hirudinaceus in the wild boars (Sus scrofa meridionalis). A total of 59 wild boars were examined showing acanthocephalan infection in 8 (13.6%) animals. In total, 49 parasites were collected with a mean intensity of 6.1. Comparatively higher infection levels were observed for males (16.7%) and young boars (14.3%); however, these epidemiological differences were statistically non-significant. Histopathological examination revealed the presence of a variable number of nodules (∼5 mm) in the intestine of M. hirudinaceus infested animals surrounded by a hyperemic-hemorrhagic halo. Several parasites were recovered from the intestinal lumen attached by the means of characteristic hooks showing necrosis in muscle layers. A moderate number of plump reactive fibroblasts and lesser numbers of fibrocytes were embedded with and at the borders of the inflammatory nodules in a moderate amount of homogeneous intensely eosinophilic fibrillary material rupturing the cell membrane. For molecular characterization, six isolated worms were amplified for the partial mitochondrial cox1 gene showing distinct interindividual variations. This first pathological and molecular description from southern Europe provided new knowledge about the diffusion of M. hirudinaceus in wild boars, furthering the research into the origin and transmission status of M. hirudinaceus in endemic localities.

In vitro effect of biological and conventional disease-modifying antirheumatic drugs on fibrocyte differentiation in patients with rheumatoid arthritis and healthy controls.

Fibrocytes are circulating bone-marrow-derived cells that migrate to organs with ongoing repair or inflammation. In the target organ, the cells differentiate, become long and spindle-shaped, and are able to produce extracellular matrix components. In fibrotic diseases, the levels of fibrocytes are increased, both in circulation and the diseased tissue. In rheumatoid arthritis (RA), fibrocytes have been proposed to be involved in the spread of the disease and possibly in RA fibrotic manifestations, as can be seen in RA interstitial lung disease (RA-ILD). Therefore, we aimed to investigate a range of current RA treatment modalities (corticosteroids and conventional and biological disease-modifying antirheumatic drugs (DMARDs)) regarding their effect on in vitro fibrocyte differentiation. A total of 10 participants were included (5 patients with RA and 5 healthy controls). Peripheral blood mononuclear cells (PBMCs) were isolated and cultured for 5 days with prednisolone, conventional DMARDs (methotrexate, sulfasalazine, and hydroxychloroquine), and biological DMARDs (etanercept, tocilizumab, adalimumab, abatacept, and rituximab). The numbers of fibrocytes were counted. Dose-response data for abatacept and tocilizumab were collected. Abatacept and prednisolone significantly suppressed differentiation of PBMC into fibrocytes compared with control (p=0.02 and p<0.01, respectively) (n=10). In overall analysis (n=10), abatacept reduced fibrocyte levels with an average of 44% overall and 71% in the RA group compared with the control wells. Tocilizumab reduced the fibrocyte count by 63% overall and 45% in the RA group, although it was not significant (p=0.07 and p=0.06, respectively). Both tocilizumab and abatacept display a dose-response relationship. Abatacept and prednisolone suppress the differentiation of mononuclear cells to mature fibrocytes in vitro in patients with RA, and data indicate a similar effect of tocilizumab; this was further supported by the observed dose-response relationship. Clinical trials are needed to compare the effect of these drugs on fibrotic RA manifestations, for example, RA-ILD.

Association of Circulating Fibrocytes With Fibrostenotic Small Bowel Crohn's Disease.

Fibrocytes are hematopoietic cells with features of mesenchymal cells found in the circulation and inflammatory sites implicated in promoting fibrosis in many fibroinflammatory diseases. However, their role(s) in the development of intestinal fibrosis is poorly understood. Here, we investigated a potential role of fibrocytes in the development of fibrosis in Crohn's disease (CD) and sought factors that may impact their development and function. Plasma and mononuclear cells were collected from patients with and without fibrostenotic CD. Fibrocytes defined as CD11b+, CD34+, and Collagen 1+ were correlated with clinical assessments of fibrosis, including evaluation using intestinal ultrasound. We measured the levels of relevant circulating molecules via Luminex and studied the effect of patient plasma proteins on fibrocyte differentiation. Fibrocyte numbers were increased in CD patients with stricturing Crohn's disease compared with patients with an inflammatory phenotype (P = .0013), with strong correlation between fibrocyte numbers and acoustic radiation force impulse (ARFI), a measure of bowel elasticity on intestinal ultrasound (R = .8383, P = .0127). Fibrostenotic plasma was a more potent inducer of fibrocyte differentiation in both primary human monocytes and cell line and contained increased levels of cytokines implicated in fibrocyte differentiation compared with plasma from inflammatory patients. Interestingly, increased fibrocyte numbers at time of ultrasound were associated with escalation of medical therapy and endoscopic/surgical management of small bowel strictures at 30 months follow-up. Circulating fibrocytes strongly correlate with fibrostenotic disease in CD, and they may serve as predictors for escalation of medical +/- surgical therapy.

Systemic Fibrocyte Levels and Keloid Expression of the Chemoattractant CXCL12 Are Upregulated Compared With Patients With Normal Scar.

Fibrocytes are bone marrow mesenchymal precursors with a surface phenotype compatible with leukocytes, fibroblasts, and hematopoietic progenitors that have been shown to traffic to wound healing sites in response to described chemokine pathways. Keloids are focal fibrotic responses to cutaneous trauma characterized by disordered collagen, which may be associated with elevated systemic fibrocyte levels and/or wound bed chemokine expression. Blood specimens from patients with longstanding keloids and those who form grossly normal scars were assayed by fluorescence activated cell sorting analysis for fibrocytes (CD45+, Col I+). The expression of the fibrocyte chemotactic cell surface marker CXCR4, intracellular markers of fibroblast differentiation (pSMAD2/3), and plasma levels of the CXCR4 cognate CXCL12 were compared. Keloid specimens and grossly normal scars were excised, and local expression of CXCL12 was assayed. Keloid-forming patients demonstrated a significantly greater number of circulating fibrocytes (17.4 × 105 cells/mL) than control patients (1.01 × 105 cells/mL, P = 0.004). The absolute number of fibrocytes expressing CXCR4 was significantly greater (P = 0.012) in keloid-forming patients. Systemic CXCL12 levels were insignificantly greater in keloid-forming patients than controls. Keloid specimens had significantly greater CXCL12 expression (529.3 pg/mL) than normal scar (undetectable). Systemic fibrocyte levels and the CXCR4/CXCL12 biologic axis responsible for fibrocyte trafficking to areas of regional fibrosis were both upregulated in patients who form keloids compared with controls. Keloids persistently expressed CXLC12, which serves both as the main chemoattractant for fibrocytes and a downstream mediator for local inflammation, suggesting a role for this biologic axis in keloid formation and possibly recurrence.

Abstract 107: Identifying the role of fibrocytes in obesity-induced mammary gland fibrosis

Abstract Obesity significantly increases breast cancer risk. In addition, obese breast cancer patients have an overall worsened prognosis. The complex relationship between obesity and breast tumor growth and aggressiveness is still being examined. Within breast adipose tissue, obesity causes a state of chronic, macrophage-driven inflammation. Chronic inflammation is associated with increased extracellular matrix (ECM) deposition, however, the underlying mechanisms are not completely understood. In mouse models, increased collagen within the mammary microenvironment is a risk factor for tumor formation, as well as more aggressive tumors. To understand how obesity affects collagen deposition in the mammary gland, we used a diet-induced obesity mouse model. We demonstrated that there was significantly greater collagen deposition around the mammary ducts of high-fat diet (HFD) fed mice compared to control diet (CD) fed mice. To understand how myeloid lineage cells contribute to this fibrosis, CD11b+ cells were sorted from mammary glands of CD- and HFD-fed mice using magnetic beads. When cultured, a population of these sorted CD11b+ cells formed adherent colonies, and colony formation was significantly increased in the CD11b+ cells isolated from HFD-fed mice. When examined further, these colonies expressed myofibroblast markers smooth muscle actin (SMA) and collagen I. These colony-forming CD11b+ cells are consistent with fibrocytes, which have been studied in both chronic inflammatory and fibrotic diseases, but have not been studied in obesity. Fibrocytes are a multipotent, bone-marrow-derived population of cells that originate as myeloid progenitor cells and have characteristics of both macrophages and myofibroblasts. Consistent with an increase in fibrocytes in the mammary gland, myeloid progenitor cells (CD45+CD11b+CD34+) were significantly increased in the bone marrow of HFD-fed mice, indicating an upregulation in the progenitor cell population for both monocytes/macrophages and fibrocytes. To examine differentiation of fibrocytes within the mammary gland, FACS-isolated myeloid progenitor cells from the bone marrow of GFP positive mice were transplanted into the inguinal mammary glands of HFD-fed CCR2 null mice, which have limited movement of myeloid lineage cells out of the bone marrow. Within the mammary glands of these transplanted mice, we observed GFP positive cells that also expressed SMA. Together, our results suggest that chronic inflammation within the obese mammary gland leads to increased fibrocyte numbers, as well as increased collagen deposition around mammary ducts. The effects of obesity on breast tissue fibrosis, as well as the cells responsible for this fibrosis, must be elucidated to better address the risk of breast tumor development in obese women. Citation Format: Genevra M. Kuziel, Lisa M. Arendt. Identifying the role of fibrocytes in obesity-induced mammary gland fibrosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 107.

CLL Cell-Derived Exosomes Promote Bone Marrow Fibrosis and Inhibit Normal Hematopoietic Colony Proliferation

CLL Cell-Derived Exosomes Promote Bone Marrow Fibrosis and Inhibit Normal Hematopoietic Colony Proliferation

Anti-IgE therapy inhibits chemotaxis, proliferation and transformation of circulating fibrocytes in patients with severe allergic asthma.

Circulating fibrocytes act as precursors of myofibroblasts, contribute to airway remodelling in chronic asthma and migrate to injured tissues by expressing CXCR4 and CCR7. Anti-IgE therapy improves severe allergic asthma (SAA) control and airway remodelling in T2-high SAA. The effects of anti-IgE therapy on fibrocyte activities were investigated in this study. The expression of CCR7, CXCR4, ST2 and α-SMA (α-smooth muscle actin) in both circulating and cultured fibrocytes from all patients with asthma was measured, and was repeated after omalizumab treatment in SAA. Fibrocytes recruitment, proliferation and transformation were also measured in response to anti-IgE therapy. Omalizumab effectively improved asthma control and pulmonary function in T2-high SAA, associated with a decline in serum levels of IL-33 and IL-13. Omalizumab down-regulates CXCR4 and CCR7 expression of fibrocytes, which could suppress fibrocyte recruitment into the lungs. Omalizumab also suppressed the increased number of fibrocytes and α-SMA+ fibrocytes within the cultured non-adherent non-T (NANT) cells after 3-7 days of culture. The decrease in serum levels of IL-33 by omalizumab contributed to the effectiveness in inhibiting fibrocyte recruitment, proliferation and myofibroblast transformation through IL-33/ST2 axis. The elevated IL-13 expression in SAA patients potentiated the effects of IL-33 by increasing ST2 expression. Omalizumab reduced the number of circulating fibrocytes, cell and number of fibrocytes as well as α-SMA+ fibrocytes after 3-7 days of culture in SAA patients. IL-33 and IL-13 may be implicated in the effectiveness of omalizumab in inhibiting fibrocyte activation contributing partly to the clinical benefits in reducing lamina propria and basement membrane thickening.