Differences In Collagen Deposition Research Articles

Effects of Moderate Exercise Training on Cancer-Induced Muscle Wasting.

Muscle wasting is a common phenomenon in oncology and seems to be attenuated by exercise training. The aim of this study is to determine the degree of aggressiveness of cancer-induced muscle wasting in two different phenotypic muscles. It will also determine whether exercise training can attenuate this muscle dysfunction. Fifty Sprague Dawley rats were randomly assigned to four experimental groups: two breast cancer model groups (sedentary and exercise) and two control groups (sedentary and exercise). Breast cancer was induced by 1-methyl-1-nitrosoureia (MNU). After 35 weeks of endurance training, animals were sacrificed, and gastrocnemius and soleus muscles harvested for morphometric analysis. In sedentary tumor-bearing animals, a significant reduction in cross-sectional area was found in both muscles (p < 0.05). Interstitial fibrosis was significantly higher in the gastrocnemius muscle of the sedentary tumor-bearing animals (p < 0.05), but not in the soleus muscle. In the gastrocnemius of sedentary tumor-bearing animals, a shift from large to small fibers was observed. This cancer-related muscle dysfunction was prevented by long-term exercise training. In sedentary animals with tumors, the gastrocnemius muscle showed a very pronounced reduction in cross-sectional area and a marked degree of interstitial fibrosis. There was no difference in collagen deposition between tumor groups, and the soleus muscle showed a less pronounced but significant reduction in cross-sectional area. These contrasting results confirm that cancer-induced muscle wasting can affect specific types of fibers and specific muscles, namely fast glycolytic muscles, and that exercise training can be used to improve it.

Depot- and diabetes-specific differences in norepinephrine-mediated adipose tissue angiogenesis, vascular tone, collagen deposition and morphology in obesity

AimsNorepinephrine (NE) is a known regulator of adipose tissue (AT) metabolism, angiogenesis, vasoconstriction and fibrosis. This may be through autocrine/paracrine effects on local resistance vessel function and morphology. The aims of this study were to investigate, in human subcutaneous and omental adipose tissue (SAT and OAT): NE synthesis, angiogenesis, NE-mediated arteriolar vasoconstriction, the induction of collagen gene expression and its deposition in non-diabetic versus diabetic obese subjects. Materials and methodsSAT and OAT from obese patients were used to investigate tissue NE content, tyrosine hydroxylase (TH) density, angiogenesis including capillary density, angiogenic capacity and angiogenic gene expression, NE-mediated arteriolar vasoconstriction and collagen deposition. Key findingsIn the non-diabetic group, NE concentration, TH immunoreactivity, angiogenesis and maximal vasoconstriction were significantly higher in OAT compared to SAT (p < 0.05). However, arterioles from OAT showed lower NE sensitivity compared to SAT (10−8 M to 10–7.5 M, p < 0.05). A depot-specific difference in collagen deposition was also observed, being greater in OAT than SAT. In the diabetic group, no significant depot-specific differences were seen in NE synthesis, angiogenesis, vasoconstriction or collagen deposition. SAT arterioles showed significantly lower sensitivity to NE (10−8 M to 10–7.5 M, p < 0.05) compared to the non-diabetic group. SignificanceSAT depot in non-diabetic obese patients exhibited relatively low NE synthesis, angiogenesis, tissue fibrosis and high vasoreactivity, due to preserved NE sensitivity. The local NE synthesis in OAT and diabetes desensitizes NE-induced vasoconstriction, and may also explain the greater tissue angiogenesis and fibrosis in these depots.

Genomic Designs of rAAVs Contribute to Pathological Changes in the Livers and Spleens of Mice.

Recombinant AAV (rAAV) gene therapy is being investigated as an effective therapy for several diseases including hemophilia B. Reports of liver tumor development in certain mouse models due to AAV treatment and genomic integration of the rAAV vector has raised concerns about the long-term safety and efficacy of this gene therapy. To investigate whether rAAV treatment causes cancer, we utilized two mouse models, inbred C57BL/6 and hemophilia B Balb/C mice (HemB), to test if injecting a high dose of various rAAV8 vectors containing or lacking hFIX transgene, a Poly-A sequence, or the CB or TTR promoter triggered liver fibrosis and/or cancer development over the course of the 6.5-month study. We observed no liver tumors in either mouse cohort regardless of rAAV treatment through ultrasound imaging, gross anatomical assessment at sacrifice, and histology. We did, however, detect differences in collagen deposition in C57BL/6 livers and HemB spleens of rAAV-injected mice. Pathology reports of the HemB mice revealed many pathological phenomena, including fibrosis and inflammation in the livers and spleens across different AAV-injected HemB mice. Mice from both cohorts injected with the TTR-hFIX vector demonstrated minimal adverse events. While not tumorigenic, high dose of rAAVs, especially those with incomplete genomes, can influence liver and spleen health negatively that could be problematic for cementing AAVs as a broad therapeutic option in the clinic.

Glypican‐1 and Remodeling Cardiac Hypertrophy.

Heart failure impacts about 5.7 million people in the U.S. alone and the clinical signs often arise from changes in heart function. Cardiac hypertrophy is a known contributor to impaired cardiac contractility and ejection fraction. The heart deals with a working relationship with volume and pressure and thus mechanosensitive proteins may play a role on heart function. This study investigates the role of heparan sulfate proteoglycans, specifically syndecan1 (Sdc1) and glypican1 (Gpc1) on heart function and hypertrophy. We investigated if global deletion of Gpc1 and Sdc1 in mice alters heart histological features and thus cardiac function. Global male knockout mice for Sdc1 (Sdc1KO) and Gpc1 (Gpc1KO) were used and compared to its respective controls C57B6 and CD1 (7 weeks old). Left ventricular posterior wall thickness at end diastole (LVPWd), interventricular septal thickness at end of diastole (IVSTd) and left ventricular internal diameter in diastole (LVIDd) and myocyte cross‐sectional area in the left ventricle were assessed by transmission microscopy using hematoxylin &amp; eosin (H&amp;E) staining. Collagen deposition was assessed by Masson’s Trichrome staining. No differences in heart dimensions (LVPWd, IVSTd, LVIDd) were found between C57B6 and Sdc1KO. IVSTd and LVPWd was increased in Gpc1KO compared to CD1 (IVSTd: 1.15 mm for Gpc1KO and 1.03 mm for CD1; LVPWd: 0.75 mm for Gpc1KO and 0.64 mm for CD1). Both knock out lines showed decreased myocyte cross‐sectional area in the left ventricle size compared to its control (203.86 μm2 for Gpc1KO, 248.43 μm2 for CD1, 194.64 μm2 for Sdc1KO, and 239.02 μm2 for C57B6). Blind scoring of collagen staining showed that there was not a significant difference in collagen deposition between Gpc1KO and CD1 (1.14 for Gpc1KO and 0.99 for CD1). Taking together, these findings indicate that Sdc1KO and Gpc1KO show alterations in cardiac histological features. Our data raises the possibility of heparan sulfate proteoglycans being involved in cardiomyocyte proliferation or development. Particularly, Gpc1KO show the unique characteristic of having a hypertrophic heart without collagen deposition. Heparan sulfate proteoglycans may play a key role in cardiac function and we speculate that they may be involved in heart disease progression.Support or Funding InformationDepartment of Anesthesiology, College of Medicine, University of Arizona, Tucson

Does CO2 pneumoperitoneum in laparoscopy interfere with collagen deposition in abdominal surgical wounds?

Purpose To determine by histomorphometric analysis whether CO2 pneumoperitoneum interferes with collagen deposition in surgical wounds in the aponeurosis of rats.Methods This experiment involved 80 male Wistar rats, randomly allocated into four groups according to pneumoperitoneum period (PRE: 30 min preoperatively; POST: 30 min postoperatively; PP: 30 min pre- and postoperatively; C: control group). CO2 pneumoperitoneum was insufflated to 5 mmHg of pressure. A laparotomy was performed; 1 cm of the left colon was then resected, and an end-to-end anastomosis was performed to simulate surgical trauma, after which the abdominal wall was closed. On postoperative days 7 or 14, a sample of the abdominal wall was collected, stained with picrosirius red and observed under polarized light in an optical microscope. The amount of collagen was estimated by computerized histomorphometric analysis.Results There were no significant differences in collagen deposition between the control and experimental groups on postoperative days 7 (p=0.720) or 14 (p=0.933). The amount of collagen increased as expected in all groups between postoperative days 7 and 14 (p=0.0003).Conclusion At 5 mmHg, CO2 pneumoperitoneum does not interfere with collagen deposition in abdominal wall surgical wounds in rats.

Plasma-based biomaterials for the treatment of cutaneous radiation injury.

ABSTRACTCutaneous wounds caused by an exposure to high doses of ionizing radiation remain a therapeutic challenge. While new experimental strategies for treatment are being developed, there are currently no off‐the‐shelf therapies for the treatment of cutaneous radiation injury that have been proven to promote repair of the damaged tissues. Plasma‐based biomaterials are biologically active biomaterials made from platelet enriched plasma, which can be made into both solid and semi‐solid forms, are inexpensive, and are available as off‐the‐shelf, nonrefrigerated products. In this study, the use of plasma‐based biomaterials for the mitigation of acute and late toxicity for cutaneous radiation injury was investigated using a mouse model. A 2‐cm diameter circle of the dorsal skin was irradiated with a single dose of 35 Gy followed by topical treatment with plasma‐based biomaterial or vehicle once daily for 5 weeks postirradiation. Weekly imaging demonstrated more complete wound resolution in the plasma‐based biomaterial vs. vehicle group which became statistically significant (p < 0.05) at weeks 12, 13, and 14 postmaximum wound area. Despite more complete wound healing, at 9 and 17 weeks postirradiation, there was no statistically significant difference in collagen deposition or skin thickness between the plasma‐based biomaterial and vehicle groups based on Masson trichrome staining nor was there a statistically significant difference in inflammatory or fibrosis‐related gene expression between the groups. Although significant improvement was not observed for late toxicity, plasma‐based biomaterials were effective at promoting wound closure, thus helping to mitigate acute toxicity.

Imaging of Murine Whole Lung Fibrosis by Large Scale 3D Microscopy aided by Tissue Optical Clearing

Pulmonary fibrosis, characterized by excessive collagen deposition in the lungs, comprises a key and debilitating component of chronic lung diseases. Methods are lacking for the direct visualization of fibrillar collagen throughout the whole murine lung, a capability that would aid the understanding of lung fibrosis. We combined an optimized organ-level optical clearing (OC) approach with large-scale, label-free multiphoton microscopy (MPM) and second harmonic generation microscopy (SHGM) to reveal the complete network of fibrillar collagen in whole murine lungs. An innate inflammation-driven model based on repetitive poly(I:C) challenge was evaluated. Following OC, mosaic MPM/SHGM imaging with 3D reconstruction and whole organ quantitative analysis revealed significant differences in collagen deposition between PBS and poly(I:C) treated lungs. Airway specific analysis in whole lung acquisitions revealed significant sub-epithelial fibrosis evident throughout the proximal conductive and distal airways with higher collagen deposition in the poly(I:C) group vs PBS group. This study establishes a new, powerful approach based on OC and MPM/SHGM imaging for 3D analysis of lung fibrosis with macroscopic views of lung pathology based on microscopy and providing a new way to analyze the whole lung while avoiding regional sampling bias.

Role of Gut-Derived Endotoxin on Type I Collagen Production in the Rat Pancreas After Chronic Alcohol Exposure.

Pancreatic fibrosis is a key pathological feature of alcoholic chronic pancreatitis (ACP). Bacterial endotoxin lipopolysaccharide (LPS) is considered as an important cofactor in the fibrogenesis of ACP. However, there are limitations in the use of exogenous LPS for evaluating the role of endotoxin in ACP pathogenesis. In this study, we determined the relationship between the concentration of LPS in the portal vein and pancreatic type I collagen (Col1) content in chronic alcohol-fed rats. Male Sprague Dawley rats were divided into 2 groups and fed with Lieber-DeCarli isocaloric control (CON) liquid diet or ethanol (EtOH) (15g/kg/d) liquid diet. Eleven CON or EtOH rats were euthanized at the end of week 8, 9, or 10. The plasma LPS from portal vein was determined. Pancreatic inflammatory injury and fibrosis were assessed. Pancreatic stellate cells (PSCs) and macrophages were identified; pancreatic type I collagen alpha 1 (Col1A1) and Toll-like receptor (TLR4) mRNA and protein were examined; pancreatic chemokines and transforming growth factor-beta1 (TGF-β1) were determined. Pancreatic inflammatory scores were increased in 10-week EtOH rats compared with CON rats, but there was no significant difference in collagen deposition between 2 groups. The levels of portal vein LPS and pancreatic TLR4 and Col1A1 mRNA and protein were increased in a time-dependent fashion in EtOH rats, with the highest levels occurring at 10weeks. Additionally, by 8weeks, pancreatic TLR4 and Col1A1 mRNA in EtOH rats were statistically increased as compared to CON rats, whereas portal vein LPS remained unchanged. The number of PSCs and macrophages and expression of chemokines (MCP-1, MIP-1α, and RANTES), TGF-β1, or Col1A1 were significantly increased, each of which was positively correlated with the level of portal vein LPS in 10-week EtOH rats. These results suggest that LPS is associated with alcohol-induced fibrosis in pancreatitis and targeting of bacterial endotoxin may be a promising therapeutic strategy for ACP.

Involvement of matrix metalloproteinases (MMPs) and inflammasome pathway in molecular mechanisms of fibrosis.

Fibrosis is a basic connective tissue lesion defined by the increase in the fibrillar extracellular matrix (ECM) components in tissue or organ. Matrix metalloproteinases (MMPs) are a major group of proteases known to regulate the turn-over of ECM and so they are suggested to be important in tissue remodelling observed during fibrogenic process associated with chronic inflammation. Tissue remodelling is the result of an imbalance in the equilibrium of the normal processes of synthesis and degradation of ECM components markedly controlled by the MMPs/TIMP imbalance. We previously showed an association of the differences in collagen deposition in the lungs of bleomycin-treated mice with a reduced molar pro-MMP-9/TIMP-1 ratio. Using the carbon tetrachloride (CCl4) preclinical model of liver fibrosis in mice, we observed a significant increase in collagen deposition with increased expression and release of tissue inhibitors of metalloproteinase (TIMP)-1 both at 24 h and 3 weeks later. This suggests an early altered regulation of matrix turnover involved in the development of fibrosis. We also demonstrated an activation of NLRP3-inflammasome pathway associated with the IL-1R/MyD88 signalling in the development of experimental fibrosis both in lung and liver. This was also associated with an increased expression of purinergic receptors mainly P2X7. Finally, these observations emphasize those effective therapies for these disorders must be given early in the natural history of the disease, prior to the development of tissue remodelling and fibrosis.

Acticoat™ stimulates inflammation, but does not delay healing, in acute full-thickness excisional wounds.

Acticoat™ has antimicrobial and anti-inflammatory effects which aid wound healing. However, in vitro studies indicate that Acticoat™ is cytotoxic and clinical and in vivo studies suggest that it may delay healing in acute wounds. Therefore, this study investigated the effects of Acticoat™ on healing in acute full-thickness excisional wounds. Using a porcine model, healing was assessed on days 3, 6, 9 and 15 post-wounding. Five wounds dressed with Acticoat™ and five wounds dressed with polyurethane film (control) were assessed per day (n = 40 wounds). The rate of healing, inflammatory response, restoration of the epithelium and blood vessel and collagen formation were evaluated. No difference was found in the rate of healing between wounds treated with Acticoat™ and the control wounds. Inflammation was increased in Acticoat™-treated wounds on day 3 post-wounding compared to the control wounds. However, by day 15 post-wounding, the epithelium of the Acticoat™-treated wounds closely resembled normal epithelium. Acticoat™-treated wounds also contained a higher proportion of mature blood vessels, and differences in collagen deposition were apparent. Despite inducing an inflammatory response, Acticoat™ did not delay healing in acute wounds. Conversely, the improved quality of the epithelium and blood vessels within Acticoat™-treated wounds indicates that Acticoat™ has a beneficial effect on healing.

Abstract 17110: Risk Factors for Hepatic Fibrosis in Children and Adolescents After Fontan Operation

Introduction: Congestive hepatopathy is increasingly recognized as a complication of Fontan physiology. Prospective data regarding the incidence of hepatopathy and risk factors for its development are lacking. Methods: Liver biopsies were obtained as part of a routine program of comprehensive end-organ evaluation offered to all patients &gt;10 years after Fontan operation (FO) through the Single Ventricle Survivorship Program. Evaluation included cardiac catheterization and contemporaneous percutaneous liver biopsy. Quantitative determination of hepatic fibrosis was performed using Sirius red staining for collagen with automated calculation of percent positive staining per slide. Patient specific characteristics, echocardiographic findings, and hemodynamic measures were assessed and evaluated as potential risk factors for collagen deposition using Pearson correlation. Differences in collagen deposition (%CD) between subgroups were assessed using the student t-test. Results: The cohort consisted of 67 patients (36 male) at mean age of 17.3 ±4.5 years and mean time from Fontan of 14.9 ±4.5 years. Right ventricular morphology was present in 37 subjects; 30 with hypoplastic left heart syndrome. Mean %CD by Sirius red staining was 23.8 ±9.5% (range 8.7-49.4%) as compared to 2.6 ±0.3% in controls. There was significant correlation between time from Fontan and degree of Sirius red staining (r=0.33, p=0.006). Serum liver enzymes and platelet count did not correlate with %CD. The median inferior vena cava (IVC) pressure was 13 mmHg (range 6-24 mmHg) and did not correlate with %CD. There was no difference in %CD between those with a measured IVC pressure ≥13 mmHg versus those with a pressure &lt;13 mmHg. There was no difference in %CD based on ventricular morphology or severity of atrioventricular valve insufficiency. Conclusion: In this cohort of predominantly asymptomatic children and adolescents electively evaluated after FO, all exhibited evidence for hepatic fibrosis as measured by collagen deposition in the liver. Time from FO was the only factor in this cohort that was significantly associated with collagen. These findings demonstrate that liver fibrosis is an inherent feature of Fontan physiology and that the degree of fibrosis increases over time.

Bone marrow mesenchymal cells improve muscle function in a skeletal muscle re-injury model.

Skeletal muscle injury is the most common problem in orthopedic and sports medicine, and severe injury leads to fibrosis and muscle dysfunction. Conventional treatment for successive muscle injury is currently controversial, although new therapies, like cell therapy, seem to be promise. We developed a model of successive injuries in rat to evaluate the therapeutic potential of bone marrow mesenchymal cells (BMMC) injected directly into the injured muscle. Functional and histological assays were performed 14 and 28 days after the injury protocol by isometric tension recording and picrosirius/Hematoxilin & Eosin staining, respectively. We also evaluated the presence and the fate of BMMC on treated muscles; and muscle fiber regeneration. BMMC treatment increased maximal skeletal muscle contraction 14 and 28 days after muscle injury compared to non-treated group (4.5 ± 1.7 vs 2.5 ± 0.98 N/cm2, p<0.05 and 8.4 ± 2.3 vs. 5.7 ± 1.3 N/cm2, p<0.05 respectively). Furthermore, BMMC treatment increased muscle fiber cross-sectional area and the presence of mature muscle fiber 28 days after muscle injury. However, there was no difference in collagen deposition between groups. Immunoassays for cytoskeleton markers of skeletal and smooth muscle cells revealed an apparent integration of the BMMC within the muscle. These data suggest that BMMC transplantation accelerates and improves muscle function recovery in our extensive muscle re-injury model.

Su1344 Failure of Infliximab Treatment in Crohn's Disease Is Associated With the Presence of Fibrosis

G A A b st ra ct s operated for colon cancer without UC served as controls. On HE 29% vs 33% vs 54%, p=0.009). Between acute and late UC there was no difference in collagen deposition, however between UC together and controls there was more collagen I expression in the mucosa, MM and muscularis externa (50% vs 10%, p=0.02; 28% vs 10%, p=0.048; 71% vs 20%, p=0.003). In both early and long UC duration, we did not find a correlation between inflammation or collagen deposition or MM thickness. There was a negative correlation between inflammation andαSMApositivity in the submucosa (R=-0.51, p=0.003) and MM (R=-0.37, p=0.04). Conclusion In our series of colectomy specimens, there is more collagen deposition in UC than in controls. No association between disease duration and increased collagen deposition could be found. Expression of αSMA however is lower in UC and correlates with inflammation. Fibrosis in UC does not appear to increase significantly over time.

P075 Epithelial Toll-like receptor 3-dependent synthesis of complement factor B and local complement activation in inflammatory bowel disease

presence of myofibroblasts in all layers of the intestinal wall. Ulcerative colitis (UC) is classically considered to be a purely mucosal disease although rarely transmural complications such as strictures and stenosis develop. Fibrogenesis in UC has not been studied systematically yet and may be a neglected phenomenon. We therefore investigated whether there is a different fibrotic load in acute vs longstanding UC and whether the degree of fibrosis in UC correlates with the severity of inflammation. Methods: Colectomy specimens from all UC patients operated at the AMC between 2007 2012 were reviewed. Specimens from patients with recent onset refractory therapy UC (diagnosis 10 years) were selected. Patients operated for colon cancer without UC served as controls. On HE 29% vs 33% vs 54%, p = 0.009). Between acute and late UC there was no difference in collagen deposition, however between UC together and controls there was more collagen I expression in the mucosa, MM and muscularis externa (50% vs 10%, p = 0.02; 28% vs 10%, p = 0.048; 71% vs 20%, p = 0.003). In both early and long UC duration, we did not find a correlation between inflammation or collagen deposition or MM thickness. There was a negative correlation between inflammation and aSMA positivity in the submucosa (R = 0.51, p = 0.003) and MM (R = 0.37, p = 0.04). Conclusions: In our series of colectomy specimens, there is more collagen deposition in UC than in controls. No association between disease duration and increased collagen deposition could be found. Expression of aSMA however is lower in UC and correlates with inflammation. Fibrosis in UC does not appear to increase significantly over time.

P074 Expression of CCL20 and its corresponding receptor CCR6 is located to epithelium and infiltrating cells in the mucosa of IBD patients

presence of myofibroblasts in all layers of the intestinal wall. Ulcerative colitis (UC) is classically considered to be a purely mucosal disease although rarely transmural complications such as strictures and stenosis develop. Fibrogenesis in UC has not been studied systematically yet and may be a neglected phenomenon. We therefore investigated whether there is a different fibrotic load in acute vs longstanding UC and whether the degree of fibrosis in UC correlates with the severity of inflammation. Methods: Colectomy specimens from all UC patients operated at the AMC between 2007 2012 were reviewed. Specimens from patients with recent onset refractory therapy UC (diagnosis 10 years) were selected. Patients operated for colon cancer without UC served as controls. On HE 29% vs 33% vs 54%, p = 0.009). Between acute and late UC there was no difference in collagen deposition, however between UC together and controls there was more collagen I expression in the mucosa, MM and muscularis externa (50% vs 10%, p = 0.02; 28% vs 10%, p = 0.048; 71% vs 20%, p = 0.003). In both early and long UC duration, we did not find a correlation between inflammation or collagen deposition or MM thickness. There was a negative correlation between inflammation and aSMA positivity in the submucosa (R = 0.51, p = 0.003) and MM (R = 0.37, p = 0.04). Conclusions: In our series of colectomy specimens, there is more collagen deposition in UC than in controls. No association between disease duration and increased collagen deposition could be found. Expression of aSMA however is lower in UC and correlates with inflammation. Fibrosis in UC does not appear to increase significantly over time.

Subfreezing versus Room-Temperature Balloon Dilation of Benign Tracheal Stenosis: A Pilot Study in Rabbits

We conducted an experiment to compare collagen deposition in tracheal stenoses dilated with room-temperature balloons and stenoses dilated with balloons at a subfreezing temperature (-10°C). Six New Zealand white rabbits underwent endoscopic tracheal injury. Tracheal dilation was performed at 3 weeks postinjury with either a room-temperature balloon or a vascular cryoplasty balloon. Five surviving rabbits were sacrificed at either 2 weeks (n = 3) or 4 weeks (n = 2) postdilation (1 rabbit that was not able to tolerate dilation was euthanized during the procedure). A blinded pathologist graded histologic sections of the injured tracheas for collagen content. The tracheal collagen deposits in the 3 animals sacrificed at 2 weeks postdilation were all graded as moderate. However, at the 4-week postdilation examination, there was a marked difference in collagen deposition between the rabbit that underwent room-temperature dilation and the rabbit that underwent subfreezing dilation; while the former showed moderate collagen deposition, the deposition in the latter was only mild. In conclusion, this pilot study showed that tracheal dilation with balloon cryotherapy decreased collagen deposition in the injured airway of 1 animal. Larger studies are required to determine whether balloon cryotherapy improves the long-term patency of immature tracheal stenosis.

Subfreezing versus Room-Temperature Balloon Dilation of Benign Tracheal Stenosis: A Pilot Study in Rabbits

We conducted an experiment to compare collagen deposition in tracheal stenoses dilated with room-temperature balloons and stenoses dilated with balloons at a subfreezing temperature (-10°C). Six New Zealand white rabbits underwent endoscopic tracheal injury. Tracheal dilation was performed at 3 weeks postinjury with either a room-temperature balloon or a vascular cryoplasty balloon. Five surviving rabbits were sacrificed at either 2 weeks (n = 3) or 4 weeks (n = 2) postdilation (1 rabbit that was not able to tolerate dilation was euthanized during the procedure). A blinded pathologist graded histologic sections of the injured tracheas for collagen content. The tracheal collagen deposits in the 3 animals sacrificed at 2 weeks postdilation were all graded as moderate. However, at the 4-week postdilation examination, there was a marked difference in collagen deposition between the rabbit that underwent room-temperature dilation and the rabbit that underwent subfreezing dilation; while the former showed moderate collagen deposition, the deposition in the latter was only mild. In conclusion, this pilot study showed that tracheal dilation with balloon cryotherapy decreased collagen deposition in the injured airway of 1 animal. Larger studies are required to determine whether balloon cryotherapy improves the long-term patency of immature tracheal stenosis.

Effects of prokinetic drugs on the abdominal wall wound healing of rats submitted to segmental colectomy and colonic anastomosis

To assess the effect of prokinetic agents on abdominal wall wound healing in rats submitted to segmental colectomy and colonic anastomosis. Sixty rats were randomly allocated into three groups according to the agents they would receive in the postoperative period: M (metoclopramide); B (bromopride); and C (control, saline 0.9%). Surgical procedures were performed identically in all animals, and consisted of a midline laparotomy followed by resection of a 1-cm segment of large bowel with end-to-end anastomosis. The abdominal wall was closed in two layers with running stitches. Abdominal wall samples were collected on the 3rd or 7th postoperative day for measurement of breaking (tensile) strength and histopathological assessment. There were no statistically significant differences in tensile strength of the abdominal wall scar between groups M, B, and C, nor between the three and seven days after surgery subgroups. On histopathological assessment, there were no statistically significant between-group differences in collagen deposition or number of fibroblasts at the wound site Use of the prokinetic drugs metoclopramide or bromopride had no effect on abdominal wall healing in rats submitted to segmental colectomy and colonic anastomosis.

Effect of Topical Application of Different Substances on Fibroplasia in Cutaneous Surgical Wounds

Background. Fibroblasts on the edges of a surgical wound are induced to synthesize collagen during the healing process which is known as fibroplasia. Objective. The aim of this study was to determine the effect of the application of different substances on fibroplasia of cutaneous surgical wounds on rats. Materials and Methods. 48 Wistar rats were divided into three groups. A surgical wound 1 cm in diameter and 1 mm in depth was created on the dorsum of each animal. The surgical wounds were submitted to the topical application of an alcoholic extract of 30% propolis, 70% alcohol, or 0.001% dexamethasone in a cream base every 12 hours. The animals were sacrificed three, seven, 14, and 28 days postoperatively. The specimens were histologically processed and stained with Masson's trichrome. The assessment of fibroplasia was performed using a scoring system: (1) 5 to 25% collagen deposition; (2) 26 to 50% collagen deposition; (3) 51 to 75% collagen deposition; (4) more than 75% collagen deposition. Results. There were statistically significant differences in collagen deposition between the substances at all postoperative evaluation times. Conclusion. Propolis and alcohol promoted greater collagen deposition in surgical wounds than dexamethasone.

Subepithelial collagen deposition, profibrogenic cytokine gene expression, and changes after prolonged fluticasone propionate treatment in adult eosinophilic esophagitis: A prospective study

Recent research shows that both pediatric and adult patients with eosinophilic esophagitis (EoE) experience esophageal remodeling marked by increased collagen deposition in which TGF-β plays an important role. However, limited data are available on the intensity and reversibility of fibrous remodeling in adults with EoE. We sought to analyze differences in collagen deposition in the lamina propria (LP) and profibrogenic cytokine gene expression along with other changes induced by prolonged treatment with fluticasone propionate in adults with EoE. Ten adults given consecutive diagnoses of EoE were studied prospectively. Deep esophageal biopsy specimens were obtained before and after 1 year of treatment with fluticasone propionate. Collagen deposition in the LP was assessed in tissue sections with the aid of the Masson trichrome technique. IL5, TGFB1, fibroblast growth factor 9 (FGF9), and CCL18 gene expression was quantified through real-time PCR. EoE results were compared among samples from 10 adult patients with gastroesophageal reflux disease and 10 control subjects with healthy esophagi. Patients with EoE showed a significant increase in subepithelial collagen deposition; this correlated positively with eosinophil density in the LP and the patient's age. Prolonged steroid treatment induced a nonsignificant reduction in subepithelial fibrosis, which remained significantly higher than in control subjects. Profibrogenic cytokine gene expression also increased in patients with EoE, with IL5 (P < .001), FGF9 (P = .005), and CCL18 (P = .008) all significantly upregulated. After 1 year of treatment, a reduction was observed in gene expression; for CCL18 expression, this decrease was statistically significant (P < .001). Esophageal remodeling is associated with upregulated gene expression of profibrogenic cytokines in adults with EoE. Prolonged treatment with fluticasone propionate leads to a nonsignificant reduction in subepithelial collagen deposition accompanied by downregulation of profibrogenic cytokine gene expression, with that of CCL18 being especially significant.