Presence Of Fibrocytes Research Articles

The radioprotective effect of a wheat germ diet on rat myocardial tissue exposed to X-rays

Introduction: To determine whether a diet of wheat (Triticum aestivum) germ has a radioprotective effect on albino rat (Rattus rattus var. Albinus) myocardial tissue. Method: Rats between 200 and 250 g were divided into 4 groups of 6 each: Two groups were fed either a wheat diet or regular diet 16 days before and after a single exposure to 18 mSv of X-rays. The other two groups were fed the same diets but not exposed to X-rays. The animals were sacrificed, and heart tissue was submitted to histopathological study. Results: Rats fed a standard diet and exposed to X-rays presented marked hyperemia of blood vessels, necrosis, presence of connective tissue fibrocytes, loss of muscle architecture and radial arrangement. Exposed rats fed a wheat diet presented with only light necrosis and the presence of fibrocytes. Rats not exposed to X-rays had healthy myocardia. Conclusions: Wheat germ diet may have a radioprotective effect on rat myocardium.

Detection of bone marrow-derived fibrocytes in human dental pulp repair.

To explore the expression profile of CD45+/pro-collagen I+ fibrocytes in intact dental pulps as well as during wound healing in adult dental pulp tissue. A total of 16 healthy permanent teeth were obtained from young patients (18 to 25years) undergoing orthodontic treatment. Routine pulp capping with mineral trioxide aggregate (MTA) was performed under local anaesthesia to induce a mineralized barrier at the exposed surface. Teeth were extracted from patients after 7, 14 and 35days. Sections of the extracted teeth were prepared and stained for various markers using indirect immunofluorescence. Fibrocytes were counted, and the data were statistically evaluated using the Dunnett test. In uninflammed pulp tissue, a pro-collagen I-positive reaction was detected in odontoblasts, as well as in perivascular cells. Most of the CD45-positive cells were negative for pro-collagen I in normal pulp tissue, whereas CD45+/pro-collagen I+ fibrocytes were detected 7days after injury. At day 14, fibrocytes were recognized under the fibrous matrix in contact with MTA and had infiltrated into regions of new capillary formation, where the fibrocytes were positively stained for vascular endothelial growth factor. By 35days, fibrocytes were few, coincident with the formation of dentine bridges. The number of fibrocytes peaked 7days post-injury and decreased at 14days. The presence of fibrocytes in human pulp wound healing was observed. The spatiotemporal distribution of fibrocytes suggests that fibrocytes are involved in the early stages of pulp wound healing, specifically by contributing to new blood vessel formation.

Serum Amyloid P Contained in Alveolar Fluid From Patients With Acute Respiratory Distress Syndrome Mediates the Inhibition of Monocyte Differentiation into Fibrocyte.

Alveolar fibrocytes are monocyte-derived mesenchymal cells associated with poor prognosis in patients with acute respiratory distress syndrome. Our aims were to determine the following: 1) the ability of monocytes from acute respiratory distress syndrome patients to differentiate into fibrocytes; 2) the influence of the acute respiratory distress syndrome alveolar environment on fibrocyte differentiation; and 3) mediators involved in this modulation, focusing on serum amyloid P. Experimental in vitro investigation. Two ICUs of a teaching hospital. Twenty-five patients (19 mild-to-severe acute respiratory distress syndrome and six matched ventilated controls without acute respiratory distress syndrome) were enrolled. Six healthy volunteers served as non-ventilated controls. Peripheral blood mononuclear cells were isolated from acute respiratory distress syndrome, ventilated controls, and non-ventilated controls blood and cultured in vitro. Fibrocytes were counted at basal condition and after culture with broncho-alveolar lavage fluid. Plasma and broncho-alveolar lavage fluid serum amyloid P contents were determined by western blot and enzyme-linked immunosorbent assay. Serum amyloid P was located in normal and acute respiratory distress syndrome lung by immunohistochemistry. Acute respiratory distress syndrome peripheral blood mononuclear cells had a three-fold increased ability to differentiate into fibrocytes compared to ventilated controls or non-ventilated controls. Acute respiratory distress syndrome broncho-alveolar lavage fluid inhibited by 71% (55-94) fibrocyte differentiation compared to saline control. Ventilated controls' broncho-alveolar lavage fluid was a less potent inhibitor (51% [23-66%] of inhibition), whereas non-ventilated controls' broncho-alveolar lavage fluid had no effect on fibrocyte differentiation. Serum amyloid P concentration was decreased in plasma and dramatically increased in broncho-alveolar lavage fluid during acute respiratory distress syndrome. Alveolar serum amyloid P originated, in part, from the release of serum amyloid P associated with lung connective tissue during acute respiratory distress syndrome. Serum amyloid P depletion decreased the inhibitory effect of acute respiratory distress syndrome broncho-alveolar lavage fluid by 60%, whereas serum amyloid P replenishment of serum amyloid P-depleted acute respiratory distress syndrome broncho-alveolar lavage fluid restored their full inhibitory effect. The presence of fibrocytes in the lung during acute respiratory distress syndrome could result in a balance between higher ability of monocytes to differentiate into fibrocytes and the inhibitory effect of the alveolar environment, mainly dependent on serum amyloid P.

MP25-07 PROSTATIC INFLAMMATION EVOKES UPREGULATION OF NEUROTROPHINS IN SENSORY GANGLIA: POSSIBLE CONTRIBUTION TO DYSFUNCTIONAL VOIDING

INTRODUCTION AND OBJECTIVES: Chronic prostatitis/ chronic pelvic pain syndrome (CP/CPPS) is a debilitating condition characterized mainly by pelvic pain. In addition, many patients report voiding complaints and lower urinary tract symptoms (LUTS). While the mechanism behind these voiding complaints is not well understood, it is possible that inflammation induces fibrosis within the prostate, as has been hypothesized to occur in benign prostatic hyperplasia (BPH). To better understand this process, we developed two transient infectioninduced prostatitis murine models where LUTS can be studied in the presence or absence of chronic pain. METHODS: C57BL/6 (B6) and NOD/ShiLtJ (NOD) mice (5-7 weeks old) were transurethrally infected with Escherichia coli strain CP1, a bacteria from a CP/CPPS patient that clears from the prostate and bladder of mice by 30 days. At post-infection days 5, 14, and 35, the mice were pain tested for referred pain with von-Frey filaments and the prostates and bladders harvested for analysis (4-8 mice per time point). Additionally, urodynamic evaluation was completed at day 35 under urethane anesthesia. Prostate and bladder specimens were analyzed by flow cytometry and real-time quantitative PCR (QT-PCR) for the presence of cells and markers involved in fibrosis. RESULTS: B6 mice did not develop pain, however, NOD mice developed significant pain at all time points. Cystometry showed increased frequency of bladder contractions in CP-1 infected mice of both strains. By flow cytometry, B6 mice developed an increase in fibrocytes (vimentinþ, CD45þ) in the prostate at day 14 which became statistically significant at day 35. A similar but delayed trend was noted in NOD mice with an increase in fibrocytes at day 35, however, this was not statistically significant. NOD mice did develop a significant increase in vimentinþ cells (mesenchymal cells) at day 14. The bladders of B6 mice demonstrated a significant increase in vimentinþ cells at day 35 and at day 14 in the NOD mice. There was no difference in the presence of fibrocytes in the bladders. B6 mice had a >1 fold increase in expression of collagen 1a1, 1a2, aSMA, and CXCL5 at day 14 by QTPCR. A similar increase in these markers was noted in the NOD mice but at the earlier time point of day 5. CONCLUSIONS: We have demonstrated in infection-induced prostatitis murine models that urinary frequency develops in the presence and absence of pain. This is associated with the concurrent suggestion of fibrosis within the prostate, with altered kinetics of development in each model. Further studies are underway to identify the pathogenesis of LUTS in the context of inflammation and pain.

Fibrocytes contribute to inflammation and fibrosis in chronic hypersensitivity pneumonitis through paracrine effects.

Hypersensitivity pneumonitis (HP) represents a lung inflammation provoked by exposure to a variety of antigens. Chronic HP may evolve to lung fibrosis. Bone marrow-derived fibrocytes migrate to injured tissues and contribute to fibrogenesis, but their role in HP is unknown. To assess the possible participation of fibrocytes in chronic HP. CD45(+)/CXCR4(+)/Col-I(+) circulating fibrocytes were evaluated by flow cytometry, and the presence of fibrocytes in HP and normal lungs by confocal microscopy. The concentration of CXCL12 in plasma and bronchoalveolar lavage fluids was quantified by ELISA. The effect of fibrocytes on lung fibroblasts and T lymphocytes was examined in co-cultures. The percentage of circulating fibrocytes was significantly increased in patients with HP compared with healthy individuals (5.3 ± 3.4% vs. 0.8 ± 0.7%; P = 0.00004). Numerous fibrocytes were found infiltrating the HP lungs near fibroblasts and lymphocytes. Plasma CXCL12 concentration was significantly increased in patients with HP (2,303.3 ± 813.7 vs. 1,385.6 ± 318.5 pg/ml; P = 0.00003), and similar results were found in bronchoalveolar lavage fluids. The chemokine was primarily expressed by epithelial cells. In co-cultures, fibrocytes induced on lung fibroblasts a significant increase in the expression of α1 type I collagen, matrix metalloprotease-1, and platelet-derived growth factor-β. Likewise, fibrocytes induced the up-regulation of CCL2 in HP lymphocytes and fibroblasts. These findings demonstrate that high levels of fibrocytes are present in the peripheral blood of patients with chronic HP and that these cells infiltrate the HP lungs. Fibrocytes may participate in the pathogenesis of HP, amplifying the inflammatory and fibrotic response by paracrine signaling inducing the secretion of a variety of proinflammatory and profibrotic molecules.

Pathophysiology of vitreoretinal interface disorders

AbstractPathologic changes at the vitreoretinal interface and vitreomacular tractions lead to phenotypic lesions such as epiretinal membranes (ERMs), idiopathic macular holes, vitreomacular traction syndrome (VMTS) and myopic foveoschisis. In the presence of clinically evident posterior vitreous (PVD), remnants of vitreous collagen fibers and/or cellular proliferations of fibrous astrocytes or glial cells, migrate outward from the retina. Migration occuring on the inner vitreo‐retinal interface through the internal limiting membrane(ILM), in the presence of growth factors such as laminin or fibronectin, may contribute to the fibrocellular proliferation at the retinal surface. Most studies regarding idiopathic or diabetic epiretinal membranes or late stages of macular holes, described the presence of fibrocytes or myofibroblasts. More recent studies confirmed those observations by using antibodies against alpha smooth muscle actine (a‐SMA). Based on the mechanistic association between a‐SMA expression and a tractional force generation, there is little doubt that these cells represented the source of traction during the evolution of those pathologies.

First Identification of Resident and Circulating Fibrocytes in Dupuytren’s Disease Shown to Be Inhibited by Serum Amyloid P and Xiapex

Dupuytren’s disease (DD) is a common progressive fibroproliferative disorder causing permanent digital contracture. Proliferative myofibroblasts are thought to be the cells responsible for DD initiation and recurrence, although their source remains unknown. DD tissue has also been shown to harbor mesenchymal and hematopoietic stem cells. Fibrocytes are circulating cells that show characteristics of fibroblasts and they express surface markers for both hematopoietic and mesenchymal stromal cells. Fibrocytes differentiate from peripheral CD14+ mononuclear cells, which can be inhibited by serum amyloid P (SAP). In this study we have demonstrated the presence of fibrocytes in DD blood and tissue, moreover we have evaluated the effects of SAP and Xiapex (Collagenase Clostridium histolyticum) on fibrocytes derived from DD. H&E staining showed typical Spindle shaped morphology of fibrocytes. FACS analysis based on a unique combination of 3 markers, revealed the increased presence of fibrocytes in blood and tissue of DD patients. Additionally, immunohistology of DD nodule and cord tissue showed the presence of collagen 1+/CD34+ cells. No difference in plasma SAP levels was observed between DD and control. Higher concentrations of SAP significantly inhibited fibrocytes differentiated from DD derived monocytes compared to control. DD fascia derived fibrocytes showed resistance to growth inhibition by SAP, particularly nodule derived fibrocytes showed robust growth even at higher SAP concentrations compared to control. DD derived fibrocytes were positive for typical fibrocyte dual markers, i.e. Collagen 1/LSP-1 and collagen 1/CD34. Xiapex was more effective in inhibiting the growth of nodule derived cells compared to commercially available collagenase A. Our results show for the first time the increased presence of fibrocytes in DD patient’s blood and disease tissue compared to control tissue. Additionally, we evaluate the response of these fibrocytes to SAP and Xiapex therapy.

Extracorporeal cardiac shock wave therapy ameliorates myocardial fibrosis by decreasing the amount of fibrocytes after acute myocardial infarction in pigs

Extracorporeal shock wave (SW) therapy ameliorates cardiac remodeling after acute myocardial infarction (AMI). However, it remains to be examined whether and how SW therapy ameliorates myocardial fibrosis after AMI. Fibrocytes are associated with myocardial fibrosis. Thus, we examined whether SW therapy ameliorates myocardial fibrosis and whether fibrocytes are associated after AMI in pigs. AMI was created by coronary embolism. Twenty-five pigs were divided into three groups: AMI+SW group (AMI with SW therapy, n=15), AMI group (without SW therapy, n=5), and sham+SW group (SW therapy without AMI, n=5). The collagen area fraction was examined by Masson's trichrome staining. The presence of fibrocytes was identified by immunofluorescence and confocal microscopy. The location of CXCL12 was examined by immunohistochemistry. Compared with the AMI group, the AMI+SW group showed significantly ameliorated myocardial fibrosis in terms of collagen area fraction (27.21±8.13 vs. 10.13±4.96, P<0.05) and reduced fibrocytes (CD34/α-smooth muscle actin: 35.40±11.72 vs. 12.27±7.71, P<0.05; CXCR4/α-smooth muscle actin: 40.80±8.96 vs. 16.54±6.38, P<0.05). There were positive correlations between the collagen area fraction and the number of fibrocytes (r=0.936; P<0.05) and between the number of CXCR4 fibrocytes and the SDF-1/CXCL12 cells (r=0.802; P<0.05) in the three groups. The results show that SW therapy ameliorates myocardial fibrosis after AMI in pigs, which is associated with the decreased amount of fibrocytes.

Normal and abnormal vitreoretinal interface conditions

AbstractPathologic changes at the vitreoretinal interface and vitreomacular traction, lead to the phenotypic lesions as epiretinal membranes (ERMs), idiopathic macular holes, vitreomacular traction syndrome (VMTS) and myopic foveoschisis. Remnants of vitreous collagen fibers in the presence of clinically evident posterior vitreous detachment (PVD) and/or cellular proliferations of fibrous astrocytes or glial cells growing outward from the retina to the inner retinal surface through the internal limiting membrane (ILM) , in the presence of growth factors as laminin, fibronectin, may contribute to fibrocellular proliferation at the retinal surface. Most studies of idiopathic of diabetic or macular holes related epiretinal membranes, described the presence of fibrocytes or myofibroblasts and more recent studies confirmed these observations using antibodies against alpha smooth muscle actine (a‐SMA). Based on the mechanistic association between a‐SMA expression and tractional force generation, there is little doubt that these cells represented the source of traction during the evolution of those pathologies.

Pig dorsum model for examining impaired wound healing at the skin-implant interface of percutaneous devices

Percutaneous medical devices are indispensable in contemporary clinical practice, but the associated incidence of low to moderate mortality infections represents a significant economic and personal cost to patients and healthcare providers. Percutaneous osseointegrated prosthetics also suffer from a similar risk of infection, limiting their clinical acceptance and usage in patients with limb loss. We hypothesized that transepidermal water loss (TEWL) management at the skin-implant interface may improve and maintain a stable skin-to-implant interface. In this study, skin reactions in a 3-month, pig dorsum model were assessed using standard histology, immunohistochemistry, and quantitative image analysis. Immunohistochemical analysis of peri-implant tissue explants showed evidence of: continuous healing (cytokeratin 6+), hypergranulation tissue (procollagen+), hyper-vascularity (collagen 4+), and the presence of fibrocytes (CD45+ and procollagen type 1+). Importantly, the gross skin response was correlated to a previous load-bearing percutaneous osseointegrated prosthetic sheep study conducted in our lab. The skin responses of the two models indicated a potentially shared mechanism of wound healing behavior at the skin-implant interface. Although TEWL management did not reduce skin migration at the skin-implant interface, the correlation of qualitative and quantitative measures validated the pig dorsum model as a high-throughput platform for translational science based percutaneous interface investigations in the future.

The Use of Laser Doppler Imaging as a Predictor of Burn Depth and Hypertrophic Scar Postburn Injury

Hypertrophic scarring (HTS) is a fibroproliferative disorder that commonly develops after severe burn injuries. Overexpression of transforming growth factor-β (TGF-β) by an increased number of fibrocytes has been associated with increased extracellular matrix molecule expression leading to HTS. The most widely accepted adjuvant to clinical assessment of burn depth is laser Doppler imaging (LDI) and may predict injury to the dermis that corresponds to cellular and molecular changes associated with HTS. A prospective, blinded, control trial was performed comparing LDI and clinical assessment for the decision to operate. Immunohistochemistry and real-time reverse transcription polymerase chain reaction was performed to determine whether there is a correlation between histological assessment of burn depth and LDI, and the presence of fibrocytes was detected using confocal microscopy. The positive predictive value for a burn requiring a graft was calculated to be >90%. Immunohistochemistry on biopsy samples revealed an increased expression of TGF-β, connective tissue growth factor, heat shock protein 47, and collagen type I in deep burn wounds compared to superficial burns. Using the fibrocyte-specific markers procollagen type I and lymphocyte-specific protein-1, there was an increased number of fibrocytes in deep burn areas compared to superficial burn. In deep burn injuries, increased infiltration of fibrocytes occurs leading to an overexpression of TGF-β1 and connective tissue growth factor. More importantly, LDI was >90% accurate at predicting the need for excision and grafting. The accuracy of the decision to debride deep dermal burns to avoid HTS using both clinical parameters and LDI was supported by histological and biochemical measurements.

Fibrocytes are involved in the pathogenesis of human chronic kidney disease

The presence of chronic kidney disease in humans is associated with a risk of kidney function loss as well as the development of cardiovascular disease. Fibrocytes have been shown to contribute to organ fibrosis. In this study, the presence of fibrocytes was investigated immunohistochemically in kidney biopsy specimens from 100 patients with chronic kidney disease. In addition, 6 patients with thin basement membrane disease were studied as a disease control. In patients with chronic kidney disease, the infiltration of fibrocytes was observed mainly in the interstitium. The number of interstitial fibrocytes in patients with chronic kidney disease was higher than that in patients with thin basement membrane disease. The number of infiltrated fibrocytes in the interstitium correlated well with the severity of tubulointerstitial lesions, such as interstitial fibrosis, in patients with chronic kidney disease. In addition, there were significant correlations between the number of interstitial fibrocytes and the number of CD68-positive macrophages in the interstitium as well as urinary monocyte chemoattractant protein-1/CCL2 levels. In particular, there was an inverse correlation between the number of interstitial fibrocytes and kidney function at the time of biopsy. Finally, the numbers of interstitial fibrocytes and macrophages as well as urinary CCL2 levels were significantly decreased during convalescence induced by glucocorticoid therapy. These results suggest that fibrocytes may be involved in the pathogenesis of chronic kidney disease through the interaction with macrophages as well as CCL2.

Are Fibrocytes Present in Pediatric Burn Wounds?

Objective of the study is to investigate for the presence of fibrocytes, a leucocyte found at sites of injury with fibroblast-like properties, within pediatric burn wounds. Seventy 3 mm punch biopsies were taken from 53 burn wounds in 33 children between 7 months and 15 years of age at the time of planned operative debridement and grafting. After fixation and sectioning, immunohistochemistry (IHC) staining was performed for CD34, pro-collagen I, alpha smooth muscle actin, transforming growth factor beta1 and Leucocyte Specific Protein-1 (LSP-1). The presence of fibrocytes was confirmed by double immunofluorescence staining with antibodies to CD34 or LSP-1 with pro-collagen I. CD34 positive cells were present in all burn wound biopsies. Using IHC staining, in 18 patients cells positive for CD34 and pro-collagen I were identified; in 17 patients, cells positive for CD34 and alphaSMA and in 17 patients also cells positive for LSP-1 and pro-collagen I. Double immunofluorescence for CD34/pro-collagen I and LSP-1/pro-collagen I confirmed the presence of fibrocytes in specimens from 17 of 18 patients positive for these markers on IHC. Of the 17 patients whose burn wounds were complicated by hypertrophic scarring, fibrocytes were identified in 88% (n = 15) compared with 18% of those without hypertrophic scarring (P < .001). This study represents the first report of the presence of fibrocytes in acute pediatric burn wounds. These cells appear to be involved in the local response to burn wound injury and may correlate with the later development of hypertrophic burn wound scarring.

Tissue fibrocytes in patients with mild asthma: A possible link to thickness of reticular basement membrane?

BackgroundMyofibroblasts, proposed as being derived from circulating fibrocytes, are considered to be important cells in thickening of the basement membrane in patients with asthma. We have studied the correlation of tissue fibrocyte levels to basement membrane thickness and the presence of fibrocytes in bronchoalveolar lavage fluid (BALF) in steroid-naive patients with mild asthma and controls.MethodsPatients with mild asthma (n = 9) were recruited and divided into two categories based on whether or not fibroblast-like cells could be established from BALF. Non-asthmatic healthy subjects (n = 5) were used as controls. Colocalization of the fibrocyte markers CD34, CD45RO, procollagen I, and α-smooth muscle actin (α-SMA) were identified in bronchial biopsies from patients and controls by confocal microscopy. Kruskall-Wallis method was used to calculate statistical significance and Spearman coefficient of rank correlation was used to assess the degree of association.ResultsIn patients with BALF fibroblasts, a 14-fold increase of tissue cells expressing CD34/CD45RO/α-SMA and a 16-fold increase of tissue cells expressing CD34/procollagen I was observed when compared to controls (p < 0.05). In contrast, patients without BALF fibroblasts displayed a 2-fold increase when compared to controls (p < 0.05). Fibrocytes were localized close to the basement membrane which was significantly thicker in patients with BALF fibroblasts when compared to the other two groups of subjects. Furthermore, basement membrane thickness could be correlated to the number of fibrocytes in tissue (r = 0.711). Fibroblasts-like cells were cultured from BALF where 17.6% of these cells expressed CD34, CD45RO and α-SMA.ConclusionThese findings indicate a correlation between recruited fibrocytes in tissue and thickness of basement membrane. Fibroblast progenitor cells may therefore be important in airway remodeling in steroid-naive patients with mild asthma.