Total Collagen Deposition Research Articles

Interleukin-10 deficiency induces thoracic perivascular adipose tissue whitening and vascular remodeling.

Perivascular adipose tissue (PVAT) is an adipose layer, surrounding blood vessels, with a local modulatory role. Interleukin-10 (IL-10) has been shown to modulate vascular tissue. This study aimed to characterize the endogenous role of IL-10 in vascular remodeling, and PVAT phenotyping. Thoracic aortic segments from control (C57BL/6J) and IL-10 knockout (IL-10-/-) male mice were used. Analyzes of aorta/PVAT morphometry, and elastin, collagen and reticulin deposition were performed. Tissue uncoupling protein 1 (UCP1) was accessed by Western blotting. Endogenous absence of IL-10 reduced total PVAT area (p = 0.0310), and wall/lumen ratio (p = 0.0024), whereas increased vascular area and thickness (p < 0.0001). Total collagen deposition was augmented in IL-10-/-, but under polarized light, the reduction of collagen-I (p = 0.0075) and the increase of collagen-III (p = 0.0055) was found, simultaneously with reduced elastic fibers deposition (p = 0.0282) and increased deposition of reticular fibers (p < 0.0001). Adipocyte area was augmented in the IL-10 absence (p = 0.0225), and UCP1 expression was reduced (p = 0.0420). Moreover, relative frequency of white adipose cells and connective tissue was augmented in IL-10-/- (p < 0.0001), added to a reduction in brown adipose cells (p < 0.0001). Altogether, these data characterize aorta PVAT from IL-10-/- as a white-like adipocyte phenotype. Endogenous IL-10 prevents vascular remodeling and favors a brown-like adipocyte phenotype, suggesting a modulatory role for IL-10 in PVAT plasticity.

CXCL10 regulates pressure overload-induced heart failure

Rationale: Heart failure involves tissue inflammation with elevated serum levels of CXCL9 and CXCL10, which are CXCR3 receptor ligands. Both chemokines are expressed by cardiac fibroblasts and myeloid cells in mice subjected to pressure overload induced by transverse aortic constriction (TAC) surgery. Although it is known that CXCR3−/− animals are protected from cardiac remodeling induced by TAC, the role of CXCL10 is unknown. The present study was undertaken to test the hypothesis that CXCL10 is crucial in the cardiac remodeling response to pressure overload induced by TAC in mice. Methods: We subjected wild-type and CXCL10−/− mice to TAC surgery, resulting in 4 experimental groups: WT Sham, WT TAC, CXCL10−/− Sham and CXCL10−/− TAC. WGA was used to analyze the cross-sectional area of cardiomyocytes. To analyze total collagen deposition, PicroSirius Red was used. Immunohistochemistry was performed to measure the number of CD64, CD3g and CD45 positive cells. Echocardiography was used to analyze cardiac function. Results are presented as the mean and standard error of the mean. Comparisons between means were made using two-way variance analysis (ANOVA), as well as Tukey's post hoc test for parametric comparisons, or Kruskal-Wallis and Dunn‘s post hoc test for non-parametric data. Differences with p&lt;0.05 were considered significant. Results: After 1 week, the CXCL10−/− mice showed the same level of cardiac hypertrophy and similar changes in echocardiography parameters, when compared to wild-type mice. However, after 6 weeks, we observed that the CXCL10−/− mice showed an attenuation of heart weight with a reduction in the total collagen deposition compared with wild-type TAC mice. At the cellular level, the genetic deletion of CXCL10 prevented the TAC-induced increase in the cross-sectional area of cardiomyocytes. Moreover, we observed that TAC increased the number of CD3+ T-cells in the heart quantified from stained cross sections of both wild type and CXCL10−/− mice, while no differences were observed for the total number of macrophages. Importantly, echocardiographic changes, including dilation and cardiac dysfunction, induced by pressure overload in wild animals were blunted in CXCL10−/− mice. Corroborating this, the genetic deletion of CXCL10 prevented the increase in lung weight induced by TAC. Conclusion: CXCL10 regulates cardiac hypertrophy and fibrosis induced by pressure overload in mice, as well as the functional changes that characterize heart failure. We are currently unraveling the mechanism through which CXCL10 can accelerate the development of heart failure in response to cardiac pressure overload. Interaction between T cells and macrophages are likely mediating these effects. R01HL155993. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Collagen‐cellulose‐poly(l‐lactide) scaffold by electrospinning and plasma‐assisting fabrication for bone tissue engineering applications

AbstractNovel biomaterials suitable for bone tissue engineering are currently in demand, and reformulating natural and synthetic biomaterials has caught scientists' attention. Cellulose and collagen have been utilized in biomedical fields. This research aimed to fabricate collagen‐cellulose‐poly(l‐lactide) (Col‐Cel‐PLL) scaffold using collagen, cellulose, and poly( l‐lactide) through electrospinning and radiofrequency plasma treatment and to examine the scaffold's physicochemical and biological properties. Fourier transform infrared spectroscopy revealed its chemistry, and scanning electron microscopy showed fine interconnecting microfibrous fibers; it was super‐hydrophilic with low crystallinity (25.59%) and great Young's modulus (163.940 ± 8.008 MPa), and it was reasonably degraded. Regarding biological properties, the scaffold was biocompatible by supporting cell attachment and viability. Cells on the Col‐Cel‐PLL produced high total protein levels and collagen deposition. However, the alkaline phosphatase activity was significantly low.

Residual nasal polyp tissue following dupilumab therapy is associated with periostin-associated fibrosis.

Dupilumab, an anti-interleukin-4 receptor alpha monoclonal antibody, is a new treatment for severe uncontrolled chronic rhinosinusitis with nasal polyps. However, data on the effect of dupilumab on histological changes in nasal polyp tissue are lacking. We aimed to investigate the effect of dupilumab on real-life clinical conditions and nasal polyp tissues from patients with eosinophilic chronic rhinosinusitis (ECRS), which is a refractory subtype. We conducted an open-label, prospective, observational, single-centre study on 63 patients with refractory ECRS on the basis of the criteria of the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis Study. These patients had a history of surgery and received dupilumab for 24weeks. Patient-reported sinonasal symptoms, T&T olfactometry and nasal polyp scores were prospectively evaluated. In 23 patients with residual nasal polyps following dupilumab treatment, changes in systemic and local periostin expression, and total collagen deposition in nasal polyp tissues were investigated before and after dupilumab administration. Dupilumab rapidly improved sinonasal symptoms and reduced the nasal polyp score 24weeks after initiation. 40 (63.5%) patients had resolution of nasal polyps, but the reduction was limited in the remaining 23 (36.5%) patients. Periostin expression in serum and nasal lavage fluid was decreased, whereas periostin and the total collagen deposition area in subepithelial tissues in residual nasal polyps were enhanced after dupilumab administration. Dupilumab improves sinonasal symptoms and reduces the nasal polyp score in refractory ECRS. Periostin-associated tissue fibrosis may be involved in the differential effect of dupilumab on nasal polyp reduction.

Alamandine attenuates oxidative stress in the right carotid following transverse aortic constriction in mice

ObjectivePressure overload can result in significant changes to the structure of blood vessels, a process known as vascular remodeling. High levels of tension can cause vascular inflammation, fibrosis, and structural alterations to the vascular wall. Prior research from our team has demonstrated that the oral administration of alamandine can promote vasculoprotective effects in mice aorta that have undergone transverse aortic constriction (TAC). Furthermore, changes in local hemodynamics can affect the right and left carotid arteries differently after TAC. Thus, in this study, we aimed to assess the effects of alamandine treatment on right carotid remodeling and the expression of oxidative stress-related substances induced by TAC. Methods and resultsMale C57BL/6 mice were categorized into three groups: Sham, TAC, and TAC treated with alamandine (TAC+ALA). Alamandine treatment was administered orally by gavage (30 µg/kg/day), starting three days before the surgery, and continuing for a period of fourteen days. Morphometric analysis of hematoxylin and eosin-stained sections revealed that TAC induced hypertrophic and positive remodeling in the right carotid artery. Picrosirius Red staining also demonstrated an increase in total collagen deposition in the right carotid artery due to TAC-induced vascular changes. Alamandine treatment effectively prevented the increase in reactive oxygen species production and depletion of nitric oxide levels, which were induced by TAC. Finally, alamandine treatment was also shown to prevent the increased expression of nuclear factor erythroid 2-related factor 2 and 3-nitrotyrosine that were induced by TAC. ConclusionOur results suggest that alamandine can effectively attenuate pathophysiological stress in the right carotid artery of animals subjected to TAC.

Col1a2-Deleted Mice Have Defective Type I Collagen and Secondary Reactive Cardiac Fibrosis with Altered Hypertrophic Dynamics.

The adult cardiac extracellular matrix (ECM) is largely comprised of type I collagen. In addition to serving as the primary structural support component of the cardiac ECM, type I collagen also provides an organizational platform for other ECM proteins, matricellular proteins, and signaling components that impact cellular stress sensing in vivo. Here we investigated how the content and integrity of type I collagen affect cardiac structure function and response to injury. We generated and characterized Col1a2-/- mice using standard gene targeting. Col1a2-/- mice were viable, although by young adulthood their hearts showed alterations in ECM mechanical properties, as well as an unanticipated activation of cardiac fibroblasts and induction of a progressive fibrotic response. This included augmented TGFβ activity, increases in fibroblast number, and progressive cardiac hypertrophy, with reduced functional performance by 9 months of age. Col1a2-loxP-targeted mice were also generated and crossed with the tamoxifen-inducible Postn-MerCreMer mice to delete the Col1a2 gene in myofibroblasts with pressure overload injury. Interestingly, while germline Col1a2-/- mice showed gradual pathologic hypertrophy and fibrosis with aging, the acute deletion of Col1a2 from activated adult myofibroblasts showed a loss of total collagen deposition with acute cardiac injury and an acute reduction in pressure overload-induce cardiac hypertrophy. However, this reduction in hypertrophy due to myofibroblast-specific Col1a2 deletion was lost after 2 and 6 weeks of pressure overload, as fibrotic deposition accumulated. Defective type I collagen in the heart alters the structural integrity of the ECM and leads to cardiomyopathy in adulthood, with fibroblast expansion, activation, and alternate fibrotic ECM deposition. However, acute inhibition of type I collagen production can have an anti-fibrotic and anti-hypertrophic effect.

The effect of extracorporeal shock wave on joint capsule fibrosis in rats with knee extension contracture: a preliminary study

ABSTRACT The purpose of this study was to observe the therapeutic effect of extracorporeal shock wave (ESW) on extensional joint contracture of knee joint in rats and its mechanism on articular capsule fibrosis. Thirty-two SD rats were randomly divided into blank control, immobilization, natural recovery, and ESW intervention groups. Except for the control group, the left knee joints of other rats were fixed with external fixation brace for 4 weeks when they were fully extended to form joint contracture. The effect of intervention was assessed by evaluating joint contracture, total cell count and collagen deposition in joint capsule, and protein expression levels of TGF-β1, p-Smad2/3, Smad2/3, p-JNK, JNK, I and III collagen in joint capsule. ESW can effectively reduce arthrogenic contracture, improve the histopathological changes of anterior joint capsule, inhibit the high expression of target protein and the excessive activation of TGF-β1/Smad2/3/JNK signal pathway. Inhibition of excessive activation of TGF-β1/Smad2/3/JNK pathway may be one of the potential molecular mechanisms by which extracorporeal shock wave can play a role.

JMJD3 Promotes Myeloid Fibroblast Activation and Macrophage Polarization in Kidney Fibrosis.

Renal fibrosis is a common feature of chronic kidney disease. Myeloid fibroblasts and macrophages contribute significantly to the pathogenesis of renal fibrosis. However, the molecular mechanisms underlying myeloid fibroblast activation and macrophage polarization are not fully understood. In this study, we examined the role of JMJD3 in myeloid fibroblast activation, macrophage polarization, and renal fibrosis development in a preclinical model of obstructive nephropathy. To examine the role of JMJD3 in renal fibrosis, we generated mice with global or myeloid cell-specific deletion of JMJD3, and we treated wild-type mice with vehicle or GSK-J4, a selective JMJD3 inhibitor. Mice were subjected to unilateral ureteral obstructive injury to induced renal fibrosis. JMJD3 expression was significantly increased in the kidneys during the development of renal fibrosis, which was associated with an increase in H3K27 dimethylation. Mice with global or myeloid JMJD3 deficiency exhibited significantly reduced total collagen deposition and extracellular matrix protein production, myeloid fibroblast activation, and M2 macrophage polarization in the obstructed kidney. Moreover, IFN regulatory factor 4, a mediator of M2 macrophage polarization, was significantly induced in the obstructed kidneys, which was abolished by JMJD3 deficiency. Furthermore, pharmacological inhibition of JMJD3 with GSK-J4 attenuated kidney fibrosis, reduced myeloid fibroblast activation, and suppressed M2 macrophage polarization in the obstructed kidney. Our study identifies JMJD3 as a critical regulator of myeloid fibroblast activation, macrophage polarization, and renal fibrosis development. Therefore, JMJD3 may represent a promising therapeutic target for chronic kidney disease.

Pathologic Mechanical Signaling Mediated by Rac2 Promotes the Foreign Body Response to Biomedical Implants

PURPOSE: An estimated $170 billion is spent annually on biomedical devices including breast implants, pacemakers, neurostimulators and orthopedic prostheses around the world. However, between 10% and 30% of these devices fail prematurely. In most cases, implant failure occurs due to a phenomenon termed the foreign body response (FBR). FBR begins as a wound healing response to the trauma created from the insertion of a foreign object. A continued presence of the implant exacerbates this response, resulting in the formation of a collagenous fibrous capsule around the implanted object. This process eventually leads to device malfunction as well as distortion of the surrounding tissues. Currently, there are no FDA-approved therapies that effectively prevent debilitating fibrotic capsule formation and the resulting functional complications around biomedical devices. METHODS: We compared human breast implant tissue and a novel murine model of FBR (mechanically stimulating implant or MSI model) to identify the key signaling pathways associated with pathological FBR. Subsequently, we utilized pathway analyses to identify potential molecular targets that are central to the signaling associated with pathological FBR. Finally, we employed small molecule inhibitors of mechanotransduction signaling in our mouse model as a proof of concept for a pharmacological strategy to target FBR and analyzed its effect on FBR capsule formation using immunostaining and histopathology. RESULTS: We first identified that Rac2, a hematopoietic-specific Rho-GTPase, was differentially upregulated in Baker IV compared to Baker I breast implant capsule tissue. Additionally, single cell sequencing of murine capsule tissue from our MSI model of FBR revealed significant differences in the activation of Rac2 and associated inflammatory markers relative to standard murine implants. Finally, we demonstrated that pharmacologically blocking Rac2 signaling in our MSI model significantly reduced the degree of FBR capsule formation as measured by decreased capsule thickness, total collagen deposition, percent mature collagen, and myofibroblast activation. CONCLUSION: Our results highlight the important role of Rac2 as a mediator of pathologic foreign body response in both mice and humans. We demonstrate that pharmacological inhibition of Rac2 may potentially serve as an effective therapy to reduce FBR in patients receiving biomedical implants, thereby increasing patient quality of life and reducing implant failure rates. Further, these findings provide novel insights into the molecular mechanisms underlying fibrotic responses to implanted devices.

Possible mechanism of static progressive stretching combined with extracorporeal shock wave therapy in reducing knee joint contracture in rats based on MAPK/ERK pathway.

The study aimed to observe the therapeutic effect of static progressive stretching (SPS) combined with extracorporeal shock wave therapy (ESWT) on extension knee joint contracture in rats and the effect on the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway in the development of joint capsule fibrosis. Thirty-six Sprague Dawley rats were randomly divided into blank control group, immobilization model group, natural recovery group, ESWT intervention group, SPS intervention group, and SPS combined with ESWT intervention group. The left knee joints of the rats, except for the control group, were fixed with an external fixation brace for four weeks at full extension to form joint contractures. The therapeutic effect of each intervention was assessed by evaluating total and arthrogenic contracture, the number of total cells and collagen deposition in the anterior joint capsule, the protein levels of TGF-β1, FGF-2, and ERK2 in the anterior joint capsule, the mean optical density of upstream RAS and downstream ERK2 positive expression in the MAPK/ERK pathway. SPS in combination with ESWT was more effective in relieving joint contracture, improving the histopathological changes in the anterior joint capsule, and suppressing the high expression of target proteins and the overactivated MAPK/ERK pathway. The overactivated MAPK/ERK pathway was involved in the formation of extension knee joint contracture in rats. SPS in combination with ESWT was effective in relieving joint contracture and fibrosis of joint capsule. Moreover, the inhibition of the overactivated MAPK/ERK pathway may be the potential molecular mechanism for its therapeutic effect.

Daily Intake of Smallanthus sonchifolius (Yacon) Roots Reduces the Progression of Non-alcoholic Fatty Liver in Rats Fed a High Fructose Diet.

High-fructose diet is associated with an increased risk of dyslipidemia, metabolic syndrome, and the development of non-alcoholic fatty liver disease (NAFLD) through chronic inflammation. The present study aimed to elucidate the potential benefit of daily consumption of Smallanthus sonchifolius (yacon) roots, rich in fructooligosaccharides (FOS), on the progression to liver fibrosis, in a rat model of NAFLD induced by a high-fructose diet. Male Wistar rats were fed a standard diet (CD, n= 6) or a standard diet plus 10% fructose solution (FD; n= 18). After 20weeks, FD rats were randomly separated into the following groups (n= 6, each): FD; FD treated with yacon flour (340mg FOS/body weight; FD + Y) and FD treated with fenofibrate (30mg/kg body weight; FD + F), for 16weeks. Daily intake of yacon flour significantly reduced body weight gain, plasma lipid levels, transaminase activities, and improved systemic insulin response in FD rats. In the liver, yacon treatment decreased fructose-induced steatosis and inflammation, and reduced total collagen deposition (64%). Also, yacon decreased TGF-β1 mRNA expression (78%), followed by decreased nuclear localization of p-Smad2/3 in liver tissue. Yacon significantly reduced the expression of α-smooth muscle actin (α-SMA), Col1α1, and Col3α1 mRNAs (85, 44, and 47%, respectively), inhibiting the activation of resident hepatic stellate cells (HSCs). These results suggested that yacon roots have the potential to ameliorate liver damage caused by long-term consumption of a high-fructose diet, being a promising nutritional strategy in NAFLD management.

Spironolactone alleviates myocardial fibrosis via inhibition of Ets-1 in mice with experimental autoimmune myocarditis.

Spironolactone improves cardiac structure, function and prognosis in patients with heart failure and delays the progression of cardiac fibrosis. However, the exact underlying mechanism of this process remains to be elucidated. The present study therefore aimed to explore the protective effect and underlying mechanism of the aldosterone receptor antagonist, spironolactone, on myocardial fibrosis in mice with experimental autoimmune myocarditis (EAM). The EAM model was induced in BALB/c mice via immunization with murine cardiac α-myosin heavy chain sequence polypeptides. The cardiac function of the mice was assessed using echocardiography and the levels of inflammatory cytokines were quantified using ELISA. E26 transformation-specific sequence-1 (Ets-1) expression was knocked down using lentivirus-mediated small interference RNA. Total collagen deposition was assessed using Masson's trichrome and Ets-1, TGF-β1, Smad2/3, collagen I and III protein expression levels were detected using immunohistochemistry and western blotting. MMP-2 and MMP-9 mRNA expression levels and activity was determined using reverse transcription-quantitative PCR and gelatin zymography, respectively. The results of the present study demonstrated that spironolactone significantly improved myocardium hypertrophy, diastolic cardiac function and decreased myocardial inflammation and collagen deposition induced by EAM. Spironolactone treatment significantly inhibited Ets-1 and smad2/3 phosphorylation. In addition, inhibition of Ets-1 reduced the expression and activity of MMP-2 and MMP-9 and decreased cardiac fibrosis in EAM mice. The results indicated that the improvement of myocardial fibrosis by spironolactone may be associated with the TGF-β1/Smad-2/3/Ets-1 signaling pathway in EAM mice.

Myeloid PTEN deficiency aggravates renal inflammation and fibrosis in angiotensin II-induced hypertension.

Hypertension is a major cause of chronic kidney disease. However, the pathogenesis of hypertensive kidney disease is not fully understood. Recently, we have shown that CXCL16/phosphoinositide-3 kinase γ (PI3Kγ) plays an important role in the development of renal inflammation and fibrosis in angiotensin II (AngII) induced hypertensive nephropathy. In the present study, we examined the role of phosphatase and tensin homolog (PTEN), a major regulator of PI3K signaling, in the pathogenesis of renal inflammation and fibrosis in an experimental model of hypertension induced by AngII. We generated myeloid PTEN conditional knockout mice by crossing PTENflox/flox mice with LysM-driven Cre mice. Littermate LysM-Cre-/- PTENflox/flox mice were used as a control. Both myeloid PTEN knockout mice and their littermate control mice exhibited similar blood pressure at baseline. AngII treatment resulted in an increase in blood pressure that was comparable between myeloid PTEN knockout mice and littermate control mice. Compared with littermate control mice, myeloid PTEN knockout mice developed more severe kidney dysfunction, proteinuria, and fibrosis following AngII treatment. Furthermore, myeloid PTEN deficiency exacerbated total collagen deposition and extracellular matrix protein production and enhanced myeloid fibroblast accumulation and myofibroblast formation in the kidney following AngII treatment. Finally, myeloid PTEN deficiency markedly augmented infiltration of F4/80+ macrophages and CD3+ T cells into the kidneys of AngII-treated mice. Taken together, these results indicate that PTEN plays a crucial role in the pathogenesis of renal inflammation and fibrosis through the regulation of infiltration of myeloid fibroblasts, macrophages, and T lymphocytes into the kidney.

Abstract P363: Annexin-A1 Deficiency Exaggerates Cardiac Remodeling In Angiotensin II-induced Hypertension

Introduction: We have previously demonstrated that the naturally-occurring anti-inflammatory and pro-resolving protein Annexin-A1 (Anx-A1) limits the acute inflammatory response post myocardial infarction, but its impact on chronic inflammation, such as hypertension, has not been explored. This study aims to investigate the role of Anx-A1 in a preclinical model of hypertension, induced by angiotensin-II (Ang-II). Methods: 15-week-old male C57BL/6 or ANXA1 -/- were anesthetized (isoflurane, 2-4% v/v) and implanted with an osmotic minipump randomly assigned to receive Ang-II (0.7mg/kg/day) or vehicle (saline). Radiotelemetry recordings of blood pressure were taken at 10 intermittent timepoints from baseline to the end of the 29-day infusion period. Animals were euthanized with pentobarbitone (100mg/kg; i.p.) at endpoint and organ weights recorded and normalized to bodyweight. Left ventricle (LV) samples were stained with picrosirius red to assess total LV collagen deposition. Results: Ang II-induced mice at the end of the study had elevated mean arterial pressure (MAP), cardiac hypertrophy and fibrosis compared to normotensive mice (Table). Anx-A1 deficient mice given Ang II had an even greater increase in MAP and cardiac remodeling compared to WT. Interestingly, MAP of Anx-A1 deficient mice at baseline is significantly higher compare to C57BL/6 counterparts (Table). Conclusion: This is the first study to demonstrate that deficiency of Anx-A1 exaggerates cardiac remodeling in AngII-induced hypertension, suggesting that endogenous Anx-A1 might play previously unappreciated physiological role in regulating blood pressure. This supports the development of Anx-A1 based pharmacotherapy against hypertension-induced cardiac damage.

Effect of L-Hyp supplementation on collagen muscle histology, gene expression, growth performance, body composition and fillet texture on big size European sea bass (Dicentrarchux labrax)

Hydroxyproline (L-Hyp) is amply present in fishmeal but limited in plant-protein sources. This study was conducted to evaluate the effects of supplementation with dietary L-Hyp on the distribution of collagen types in the muscle, and on the texture, survival rate, growth rate, feed utilization, body composition as well as the expression of the gene that encodes the pro-alpha2 chains of type I collagen (Col Iα2) of large European sea bass (initial body weight 609.21 ± 75.39 g) from high plant-protein diets. Four isoproteic (42 % crude protein) and isolipidic (20 % crude lipid) experimental diets were formulated adding 0.6 (HL diet), 1.2 (HM diet), and 2% (HH diet) L-Hyp, respectively. Three periods of feeding of 45, 99 and 143 days were studied. L-Hyp supplementation at 1.2 % and 2 % significantly improved specific growth rate (SGR) and feed conversion ratio (FCR). In the white muscle, type I, IV collagen and trichromic stain were significantly higher in HH feed than the control diet. In the red muscle, only type I collagen was higher. HH diet, also increases Col Iα2 mRNA levels in muscle significantly. It can be concluded that the addition of crystalline l-Hyp at 1.2 % or 2 % in high plant-protein diets indicates positive effects on growth performance of adult European sea bass and increase in muscle total collagen deposition.

Effects of chondrogenic priming duration on mechanoregulation of engineered cartilage

Chondrocyte maturation during cartilage development occurs under diverse and dynamic mechanical environments. Mechanical stimulation through bioreactor culture may mimic these conditions to direct cartilage tissue engineering in vitro. Mechanical cues can promote chondrocyte homeostasis or hypertrophy and mineralization, depending potentially on the timing of load application. Here, we tested the effects of chondrogenic priming duration on the response of engineered human cartilage constructs to dynamic mechanical compression. We cultured human bone marrow stromal cells (hMSCs) in fibrin hydrogels under chondrogenic priming conditions for periods of 0, 2, 4, or 6 weeks prior to two weeks of either static culture or dynamic compression. We measured construct mechanical properties, cartilage matrix composition, and gene expression. Dynamic compression increased the equilibrium and dynamic modulus of the engineered tissue, depending on the duration of chondrogenic priming. For priming times of 2 weeks or greater, dynamic compression enhanced COL2A1 and AGGRECAN mRNA expression at the end of the loading period, but did not alter total collagen or glycosaminoglycan matrix deposition. Load initiation at priming times of 4 weeks or less repressed transient osteogenic signaling (RUNX2, OPN) and expression of CYR61, a YAP/TAZ-TEAD-target gene. No suppression of osteogenic gene expression was observed if loading was initiated after 6 weeks of in vitro priming, when mechanical stimulation was observed to increase the expression of type X collagen. Taken together, these data demonstrate that the duration of in vitro chondrogenic priming regulates the cell response to dynamic mechanical compression and suggests that early loading may preserve chondrocyte homeostasis while delayed loading may support cartilage maturation.

MiR155 Deficiency Reduces Myofibroblast Density but Fails to Improve Cardiac Function after Myocardial Infarction in Dyslipidemic Mouse Model.

Myocardial infarction remains the most common cause of heart failure with adverse remodeling. MicroRNA (miR)155 is upregulated following myocardial infarction and represents a relevant regulatory factor for cardiac remodeling by engagement in cardiac inflammation, fibrosis and cardiomyocyte hypertrophy. Here, we investigated the role of miR155 in cardiac remodeling and dysfunction following myocardial infarction in a dyslipidemic mouse model. Myocardial infarction was induced in dyslipidemic apolipoprotein E-deficient (ApoE−/−) mice with and without additional miR155 knockout by ligation of the LAD. Four weeks later, echocardiography was performed to assess left ventricular (LV) dimensions and function, and mice were subsequently sacrificed for histological analysis. Echocardiography revealed no difference in LV ejection fractions, LV mass and LV volumes between ApoE−/− and ApoE−/−/miR155−/− mice. Histology confirmed comparable infarction size and unaltered neoangiogenesis in the myocardial scar. Notably, myofibroblast density was significantly decreased in ApoE−/−/miR155−/− mice compared to the control, but no difference was observed for total collagen deposition. Our findings reveal that genetic depletion of miR155 in a dyslipidemic mouse model of myocardial infarction does not reduce infarction size and consecutive heart failure but does decrease myofibroblast density in the post-ischemic scar.

NLRP3 inflammasome activation determines the fibrogenic potential of PM2.5 air pollution particles in the lung

Airborne fine particulate matter (PM2.5) is known to cause respiratory inflammation such as chronic obstructive pulmonary disease and lung fibrosis. NLRP3 inflammasome activation has been implicated in these diseases; however, due to the complexity in PM2.5 compositions, it is difficult to differentiate the roles of the components in triggering this pathway. We collected eight real-life PM2.5 samples for a comparative analysis of their effects on NLRP3 inflammasome activation and lung fibrosis. In vitro assays showed that although the PM2.5 particles did not induce significant cytotoxicity at the dose range of 12.5 to 100 µg/mL, they induced potent TNF-α and IL-1β production in PMA differentiated THP-1 human macrophages and TGF-β1 production in BEAS-2B human bronchial epithelial cells. At the dose of 100 µg/mL, PM2.5 induced NLRP3 inflammasome activation by inducing lysosomal damage and cathepsin B release, leading to IL-1β production. This was confirmed by using NLRP3- and ASC-deficient cells as well as a cathepsin B inhibitor, ca-074 ME. Administration of PM2.5 via oropharyngeal aspiration at 2 mg/kg induced significant TGF-β1 production in the bronchoalveolar lavage fluid and collagen deposition in the lung at 21 days post-exposure, suggesting PM2.5 has the potential to induce pulmonary fibrosis. The ranking of in vitro IL-1β production correlates well with the in vivo total cell count, TGF-β1 production, and collagen deposition. In summary, we demonstrate that the PM2.5 is capable of inducing NLRP3 inflammasome activation, which triggers a series of cellular responses in the lung to induce fibrosis.

Age-Dependent Remodeling in Infrapatellar Fat Pad Adipocytes and Extracellular Matrix: A Comparative Study.

The infrapatellar fat pad (IFP) is actively involved in knee osteoarthritis (OA). However, a proper description of which developmental modifications occur in the IFP along with age and in absence of joint pathological conditions, is required to adequately describe its actual contribution in OA pathophysiology. Here, two IFP sources were compared: (a) IFP from healthy young patients undergoing anterior-cruciate ligament (ACL) reconstruction for ACL rupture (n = 24); (b) IFP from elderly cadaver donors (n = 23). After histopathological score assignment to confirm the absence of inflammatory features (i.e., inflammatory infiltrate and increased vascularity), the adipocytes morphology was determined; moreover, extracellular matrix proteins were studied through histology and Second Harmonic Generation approach, to determine collagens content and orientation by Fast Fourier Transform and OrientationJ. The two groups were matched for body mass index. No inflammatory signs were observed, while higher area, perimeter, and equivalent diameter and volume were detected for the adipocytes in the elderly group. Collagen III displayed higher values in the young group and a lower total collagen deposition with aging was identified. However, collagen I/III ratio and the global architecture of the samples were not affected. A higher content in elastic fibers was observed around the adipocytes for the ACL-IFPs and in the septa cadaver donor-IFPs, respectively. Age affects the characteristics of the IFP tissue also in absence of a pathological condition. Variable mechanical stimulation, depending on age-related different mobility, could be speculated to exert a role in tissue remodeling.

Cytocompatibility Properties of an Herbal Compound Solution Support I n vitro Wound Healing.

The aim of this study was to evaluate the cytocompatibility of an herbal extract compound oral rinse [StellaLife VEGA (SLife)] against relevant human cellular models of oral surgical wound healing. SL was compared to the gold standard for peri-/post-operative oral surgical use, i.e., Chlorhexidine (CHX) and to a commonly utilized essential-oil (EO) based antiseptic rinse. Fibroblasts and primary oral stem cells of the apical papilla (SCAPs) were employed to assess its comparative cytotoxicity to the active comparator antiseptic rinses and its effects on wound healing in vitro. In cytotoxicity assays, multiple timepoints were tested ranging from clinically relevant of 60-s rinsing to protracted challenge of up to 5 min, to determine dose-dependent toxicity. The SLife group consistently demonstrated minimal cytotoxicity as compared to active comparators across experimental timepoints and different cells lines. At concentrations up to 20% v/v SLife-challenged fibroblasts and SCAPs demonstrated no significant toxicity as compared to unstimulated controls (p > 0.05). When assessing wound healing, a scratch wound assay revealed significantly accelerated cell migration for SLife as compared to CHX (p < 0.05). Notably, all active comparator antiseptic rinses affected wound healing responses by significantly reducing total collagen deposition after intermittent “rinsing” intervals that simulated post-surgical oral rinsing. Nonetheless, intermittent as well as continuous challenge of cells with SLife had a positive effect in functional collagen assays. An herbal extract compound-based oral rinse was found to be cytocompatible to cells critical to oral wound healing and to promote fibroblast migration and differentiation, contrary to existing antiseptic rinses that lack selective cytotoxicity.