Interstitial Collagen Research Articles

Calanus oil attenuates isoproterenol-induced cardiac hypertrophy by regulating myocardial remodeling and oxidative stress

ABSTRACT Calanus oil, an oil extracted from the marine crustacean Calanus finmarchicus, is one of the richest sources of omega-3 and poly-unsaturated fatty acids. Although calanus oil has been shown to have a significant anti-hypertensive, anti-inflammatory, anti-fibrotic and anti-obesity effects in various cardiovascular diseases, but little is known about its effect on pathological cardiac hypertrophy. Thus, the present study was carried out to evaluate the therapeutic effect of calanus oil on cardiac hypertrophy. Cardiac hypertrophy was induced by subcutaneous injections with isoproterenol (5 mg/kg b.w) for 14 consecutive days. Calanus oil (400 mg/kg) was given orally for 4 weeks. Cardiac pathological remodeling was evaluated by echocardiography, after which morphometric, biochemical, histological and ultrastructural analyses were performed. Calanus oil treatment significantly ameliorated isoproterenol-induced structural and functional alterations in echocardiography. Calanus oil also reduced the relative heart weight, significantly decreased the elevated cardiac enzymes (LDH and CK-MB) and the lipid peroxidation marker (MDA), augmented the myocardial antioxidant status (TAC), and ameliorated the histopathological and ultrastructural changes in cardiac tissues and prevented interstitial collagen deposition. The present study, for the first time, provided morphometric, biochemical, histological and ultrastructural evidences supporting the promising anti-hypertrophic effect of calanus oil against ISO-induced cardiac hypertrophy. This anti-hypertrophic effect of calanus oil is via regulating myocardial remodeling and oxidative stress. Therefore, it could be used as potential pharmacological intervention in the management of cardiac hypertrophy.

Determination of Interstitial Collagen Deposition and Related Topography Using the Second Harmonic Generation-Based HistoIndex Platform.

Interstitial fibrosis is characterized by the increased deposition of extracellular matrix (ECM) components within the interstitial space of various organs, such as the kidneys, heart, lungs, liver, and skin. The primary component of interstitial fibrosis-related scarring is interstitial collagen. Therefore, the therapeutic application of anti-fibrotic medication hinges on the accurate measurement of interstitial collagen levels within tissue samples. Current histological measurement techniques for interstitial collagen are generally semi-quantitative in nature and only provide a ratio of collagen levels within tissues. However, the Genesis™ 200 imaging system and supplemental image analysis software, FibroIndex™, from HistoIndex™, is a novel, automated platform for imaging and characterizing interstitial collagen deposition and related topographical properties of the collagen structures within an organ, in the absence of any staining. This is achieved by using a property of light known as second harmonic generation (SHG). Using a rigorous optimization protocol, collagen structures in tissue sections can be imaged with a high degree of reproducibility and ensures homogeneity across all samples while minimizing the introduction of any imaging artefacts or photobleaching (decreased tissue fluorescence due to prolonged exposure to the laser). This chapter outlines the protocol that should be undertaken to optimize HistoIndex scanning of tissue sections, and the outputs that can be measured and analyzed using the FibroIndex™ software.

Research progress in targeting autophagy of traditional Chinese medicine and natural compounds to regulate atherosclerosis

Atherosclerosis(AS) is the common pathological basis of many ischemic cardiovascular diseases, and its formation process involves various aspects such as vascular endothelial injury and platelet activation. Vascular endothelial injury is the initiating factor of AS plaque. Monocytes are recruited to differentiate into macrophages at the damaged endothelial cells, which absorb oxidized low-density lipoprotein(ox-LDL) and slowly transform into foam cells. Smooth muscle cells(SMCs) proliferate and migrate continuously. As the only cell producing interstitial collagen fibers in the fibrous cap, SMCs largely determine whether the plaque ruptured or not. The amplifying inflammatory response during the formation of AS recruits platelets to adhere to the damaged area of vascular endothelium and stimulates excessive platelet aggregation. Autophagy activity is associated with vascular lesions and abnormal platelet activation, and excessive autophagy is considered to be a negative factor for plaque stability. Therefore, precise regulation of different types of vascular autophagy and platelet autophagy to treat AS may provide a new therapeutic perspective for the prevention and treatment of atherosclerotic ischemic cardiovascular disease. Currently, treatment strategies for AS still focus on lowering lipid levels with high-intensity statins, which often cause significant side effects. Therefore, the development of safer and more effective drugs and treatment modes is the focus of current research. Traditional Chinese medicine and natural compounds have the potential to treat AS by targeted autophagy, and have been playing an increasingly important role in the prevention and treatment of cardiovascular diseases in China. This paper summarizes the experimental studies on different vascular cell types and platelet autophagy in AS, and sums up the published research results on targeted autophagy of traditional Chinese medicine and natural plant compounds to regulate AS, providing new ideas for further research.

Salvianolic acid B attenuates tubulointerstitial fibrosis by inhibiting EZH2 to regulate the PTEN/Akt pathway

Context Salvianolic acid B (SAB) can alleviate renal fibrosis and improve the renal function. Objective To investigate the effect of SAB on renal tubulointerstitial fibrosis and explore its underlying mechanisms. Materials and methods Male C57 mice were subjected to unilateral ureteric obstruction (UUO) and aristolochic acid nephropathy (AAN) for renal fibrosis indication. Vehicle or SAB (10 mg/kg/d, i.p.) were given consecutively for 2 weeks in UUO mice while 4 weeks in AAN mice. The serum creatinine (Scr) and blood urine nitrogen (BUN) were measured. Masson’s trichrome staining and the fibrotic markers (FN and α-SMA) were used to evaluate renal fibrosis. NRK-49F cells exposed to 2.5 ng/mL TGF-β were treated with SAB in the presence or absence of 20 μM 3-DZNep, an inhibitor of EZH2. The protein expression of EZH2, H3k27me3 and PTEN/Akt signaling pathway in renal tissue and NRK-49F cells were measured by Western blots. Results SAB significantly improved the levels of Scr by 24.3% and BUN by 35.7% in AAN mice. SAB reduced renal interstitial collagen deposition by 34.7% in UUO mice and 72.8% in AAN mice. Both in vivo and in vitro studies demonstrated that SAB suppressed the expression of FN and α-SMA, increased PTEN and decreased the phosphorylation of Akt, which were correlated with the down-regulation of EZH2 and H3k27me3. The inhibition of EZH2 attenuated the anti-fibrotic effects of SAB in NRK-49Fs. Conclusion SAB might have therapeutic potential on renal fibrosis of CKD through inhibiting EZH2, which encourages further clinical trials.

Deleterious effects of cardiomyocyte-specific prostaglandin E2 EP3 receptor overexpression on cardiac function after myocardial infarction

AimsProstaglandin E2 (PGE2) is a lipid hormone that signals through 4 different G-protein coupled receptor subtypes which act to regulate key physiological processes. Our laboratory has previously reported that PGE2 through its EP3 receptor reduces cardiac contractility at the level of isolated cardiomyocytes and in the isolated working heart preparation. We therefore hypothesized that cardiomyocyte specific overexpression of the PGE2 EP3 receptor further decreases cardiac function in a mouse model of heart failure produced by myocardial infarction. Main methodsOur study tested this hypothesis using EP3 transgenic mice (EP3 TG), which overexpress the porcine analogue of human EP3 in the cardiomyocytes, and their wildtype (WT) littermates. Mice were analyzed 2 wks after myocardial infarction (MI) or sham operation by echocardiography, RT-PCR, immunohistochemistry, and histology. Key findingsWe found that the EP3 TG sham controls had a reduced ejection fraction, reduced fractional shortening, and an increased left ventricular dimension at systole and diastole compared to the WT sham controls. Moreover, there was a further reduction in the EP3 TG mice after myocardial infarction. Additionally, single-cell analysis of cardiomyocytes isolated from EP3 TG mice showed reduced contractility under basal conditions. Overexpression of EP3 significantly increased cardiac hypertrophy, interstitial collagen fraction, macrophage, and T-cell infiltration in the sham operated group. Interestingly, after MI, there were no changes in hypertrophy but there were changes in collagen fraction, and inflammatory cell infiltration. SignificanceOverexpression of EP3 reduces cardiac function under basal conditions and this is exacerbated after myocardial infarction.

Apigenin attenuates high-fat diet-induced nephropathy in rats by hypoglycemic and hypolipidemic effects, and concomitant activation of the Nrf2/antioxidant axis

• The protective potential of apigenin in rats with high-fat diet (HFD)-induced nephropathy by activation of Nrf2. • Apigenin reduced body weight. • Apigenin improved hyperglycemia, hyperinsulinemia, hyperlipidemia and renal tubular damage. • Apigenin increased the mRNA, cytoplasmic, and nuclear levels of Nrf2. • Apigenin reduced levels of GSH, SOD, CAT, MDA, TNF-α, IL-6. This study examined the protective potential of apigenin in rats with high-fat diet (HFD)-induced nephropathy, and tested its involvement in the activation of nuclear factor-erythroid 2 related factor 2 (Nrf2). Control, apigenin, HFD, HFD + apigenin, and HFD + Nrf2 inhibitor (brusatol) groups were formed. Apigenin was administered orally (50 mg/kg), and all treatments were conducted for 12 weeks. Apigenin, administered orally (50 mg/kg), significantly reduced body weight and reversed hyperglycemia, hyperinsulinemia, hyperlipidemia, renal tubular damage, and interstitial collagen deposition induced by HFD-fed rats. Additionally, apigenin significantly increased the mRNA, cytoplasmic, and nuclear levels of Nrf2 and levels of glutathione, superoxide dismutase, and catalase, but significantly reduced the levels of malondialdehyde, tumor necrosis factor-alpha, and interleukin-6, nuclear levels of nuclear factor kappa beta p65, and mRNA levels of transforming growth factor-β1, Bax, and caspase-3. Brusatol co-treatment abolished all the effects of apigenin on these markers, except for body and fat weights, glucose, and insulin. In conclusion, apigenin attenuated HFD-induced nephropathy by activating Nrf2.

Nasal irrigation with licorice extract (Glycyrrhiza glabra) in treating nasal polyps by reducing fibroblast differentiation and extracellular matrix production in TGF-β1-stimulated nasal polyp-derived fibroblasts by inhibiting the MAPK/ERK-1/2 pathway – an in vitro and in clinic study

BackgroundTo date, treating nasal polyps (NPs) is still a medical challenge. However, we have developed an innovative therapy using licorice extract (LE: Glycyrrhiza glabra) to treat rhinitis and sinusitis via nasal irrigation and have discovered that it significantly affects treatment of NPs.Hypothesis/purposeThis study investigated the mechanism of LE on NPs.Study designNPs were collected from three patients using tissue biopsies before and 2 weeks after nasal irrigation with licorice for histopathological analysis. Additionally, NPs from two patients were collected, and nasal polyp-derived fibroblasts (NPDF) were isolated and cultured.MethodsThe TGF-β1-stimulated NPDF model was used to examine the effect of LE on fibroblast differentiation (biomarker: α-SMA), the consequent production of extracellular matrix (ECM; biomarkers: fibronectin, FBN), and the functional signaling pathway.ResultsImmunohistochemistry (IHC) revealed that the number of eosinophils and the expression of α-SMA and interstitial collagen of polyps after licorice treatment significantly decreased. Additionally, RT-PCR, western blotting, and immunofluorescence (IF) showed that α-SMA and FBN expressions were significantly increased in the NPDF, which was stimulated by TGF-β1, and LE dose-dependently could effectively reduce this effect. Furthermore, western blotting showed that LE could attenuate α-SMA and FBN expressions by preventing the signaling pathway of MAPK/ERK-1/2, which IHC and IF further confirmed. In addition, LE effectively suppressed the cell migration of NPDF, which is related to polyp expansion.ConclusionLE is clinically used to treat sinusitis with NPs through nasal irrigation, which significantly reduces the size of NPs. This effect could attenuate fibroblast differentiation, ECM production and cell migration, and one of the functional mechanisms may be through inhibition of the MAPK/ERK-1/2 signaling pathway.Trial registrationISRCTN (No. 51425529) registered on 17/04/2020 (retrospectively registered) - http://www.isrctn.com/ISRCTN51425529

Protective Effect and Mechanism of Placenta Extract on Liver

The placenta contains multiple biologically active substances, which exert antioxidation, anti-inflammatory, immunomodulatory, and delayed aging effects. Its extract can improve hepatic morphology and function: on the one hand, it can reduce liver interstitial collagen deposition, lipogenesis, and inflammatory cell infiltration and improve fibrosis; on the other hand, it can prevent hepatocellular degeneration by scavenging reactive oxygen species (ROS) and inhibiting inflammatory cytokine production, further improve hepatocyte apoptosis and necrosis, and promote hepatocyte regeneration, making it a promising liver-protective agent. Current research on placenta extract (PE) mainly focuses on treating a specific type of liver injury, and there are no systematic reports. Therefore, this review comprehensively summarizes the treatment reports of PE on liver injury and analyzes its mechanism of action.

Abstract 15385: Integrin Alpha 11 is a Critical Regulator of Cardiac Remodelling, Fibrosis and Infarct Formation Following Myocardial Infarction

Cardiac fibrosis (CF), a key feature of cardiac remodelling, defined as the accumulation of excessive amounts of extracellular matrix (ECM), in response to injuries such as myocardial infarction (MI). Cardiac fibroblasts within and surrounding the injured area respond to biochemical and mechanical stimuli transforming into myofibroblasts and begin to secrete collagen. Long term collagen production reduces ventricular compliance and ultimately results in further cardiac dysfunction leading to heart failure. Mechanical activation of collagen production is understood to be a significant mediator of cardiac fibrosis. However, the mechanisms via which mechanical stimuli initiate cardiac fibroblast activation are not well understood. Therefore, we sort to investigate the role of Integrin ⍺11, a collagen binding integrin which preferentially binds to type I collagen, in response to cardiac injury. Fibroblast conditional ⍺11 knockout (KO) mice demonstrated similar cardiac function to that of Wildtype littermates (WT). However, interstitial collagen I (P<0.05) and III (P<0.0001) content was reduce along with cardiac myocyte size (P<0.0001). In response to ligation of the left anterior descending aorta ⍺11 KO mice had significantly increased Infarct size 24 hours post MI (WT=39%, ⍺11KO=64% P<0.05). Larger MI’s resulted in increased mortality in ⍺11 KO mice (22% v’s 57%, P<0.05) due to rupture. Cardiac function 2 days following MI measured by echo demonstrated that Fractional Area Change (FAC) (23% ±1.812 v’s 16%±2.311, P<0.05) and Cardiac Output (8.53ml±1.045 v’s 4.98ml±0.67, P<0.05) were significantly worse in ⍺11 KO compared to WT mice. In the later remodelling response 4 weeks post MI, FAC was again significantly worse for ⍺11 KO mice (~9% ±1.659%, P<0.0001) compared to WT (~19% ± 0.9810%). Moreover, ⍺11 KO mice that survived MI had significantly more collagen I (P<0.0001) content in the remote, peri-infarct and infarct zone’s than that of WT along with, a lack of hypertrophic response. In conclusion, the loss ⍺11 results in increased ventricular dilation, impairs cardiac function and, was associated with increased mortality due to rupture following MI. In mice which survived MI ⍺11 deletion led to increased CF and blunted cardiac myocyte hypertrophy.

Abstract 15337: Chronic Oral Finerenone Treatment Does Not Improve Left Ventricular Diastolic Compliance in Swine With Repetitive Pressure Overload-Induced HFpEF

Introduction: The non-steroidal mineralocorticoid receptor antagonist finerenone has emerged as a potential treatment for heart failure with preserved ejection fraction (HFpEF) based, in part, on initial evidence of its anti-fibrotic properties. However, it is unclear whether chronic oral finerenone therapy can reverse established cardiac fibrosis. Accordingly, we tested the efficacy of chronic oral finerenone in a porcine model of HFpEF characterized by interstitial fibrosis and reduced left ventricular (LV) diastolic compliance in the absence of co-morbidities or anatomic LV hypertrophy. Methods: Swine (n=12) were subjected to daily (1 hr) episodes of repetitive LV pressure overload (RPO) for 2 weeks using phenylephrine (24 mg/hr) to transiently elevate LVEDP to ~30 mm Hg. After 2 weeks, RPO was discontinued and animals were followed for an additional 4 weeks, during which a subset received oral finerenone (20 mg/day; n=6). LV end-diastolic volume (EDV) and pressure (EDP) were measured at normal and elevated preload to assess LV compliance (ΔLVEDV/ΔLVEDP) and post-mortem picrosirius red staining was performed to quantify interstitial fibrosis vs. normal controls (n=8). Results: Four-weeks after cessation of RPO, untreated animals exhibited a significant increase in interstitial fibrosis vs. normal controls that was attenuated in finerenone-treated animals ( Figure A ). Despite this regression of interstitial collagen, a persistent reduction in LV diastolic compliance was observed after finerenone treatment (1.18 ± 0.33 mL/mmHg vs. 2.11 ± 0.22 mL/mmHg in normal controls; p=0.04) that was comparable to that of untreated animals after RPO (0.97 ± 0.22 mL/mmHg; p=0.61; Figure B ). Conclusion: Four weeks of chronic oral finerenone treatment does not restore LV diastolic compliance in swine with RPO-induced HFpEF despite regression of interstitial collagen content, suggesting that other factors may contribute to diastolic stiffening in this model.

Only Acute but Not Chronic Thrombocytopenia Protects Mice against Left Ventricular Dysfunction after Acute Myocardial Infarction.

Platelets are major players of thrombosis and inflammation after acute myocardial infarction (AMI). The impact of thrombocytopenia on platelet-induced cellular processes post AMI is not well defined. The left anterior descending artery was ligated in C57/Bl6 mice and in two thrombocytopenic mouse models to induce AMI. Platelets from STEMI patients and from C57/Bl6 mice displayed enhanced platelet activation after AMI. This allows platelets to migrate into the infarct but not into the remote zone of the left ventricle. Acute thrombocytopenia by antibody-induced platelet depletion resulted in reduced infarct size and improved cardiac function 24 h and 21 days post AMI. This was due to reduced platelet-mediated inflammation after 24 h and reduced scar formation after 21 days post AMI. The collagen composition and interstitial collagen content in the left ventricle were altered due to platelet interaction with cardiac fibroblasts. Acute inflammation was also significantly reduced in Mpl-/- mice with chronic thrombocytopenia, but cardiac remodeling was unaltered. Consequently, left ventricular function, infarct size and scar formation in Mpl-/- mice were comparable to controls. This study discovers a novel role for platelets in cardiac remodeling and reveals that acute but not chronic thrombocytopenia protects left ventricular function post AMI.

Gaseous signal molecule SO2 regulates autophagy through PI3K/AKT pathway inhibits cardiomyocyte apoptosis and improves myocardial fibrosis in rats with type II diabetes.

Myocardial fibrosis is a key link in the occurrence and development of diabetic cardiomyopathy. Its etiology is complex, and the effect of drugs is not good. Cardiomyocyte apoptosis is an important cause of myocardial fibrosis. The purpose of this study was to investigate the effect of gaseous signal molecule sulfur dioxide (SO2) on diabetic myocardial fibrosis and its internal regulatory mechanism. Masson and TUNEL staining, Western-blot, transmission electron microscopy, RT-qPCR, immunofluorescence staining, and flow cytometry were used in the study, and the interstitial collagen deposition, autophagy, apoptosis, and changes in phosphatidylinositol 3-kinase (PI3K)/AKT pathways were evaluated from in vivo and in vitro experiments. The results showed that diabetic myocardial fibrosis was accompanied by cardiomyocyte apoptosis and down-regulation of endogenous SO2-producing enzyme aspartate aminotransferase (AAT)1/2. However, exogenous SO2 donors could up-regulate AAT1/2, reduce apoptosis of cardiomyocytes induced by diabetic rats or high glucose, inhibit phosphorylation of PI3K/AKT protein, up-regulate autophagy, and reduce interstitial collagen deposition. In conclusion, the results of this study suggest that the gaseous signal molecule SO2 can inhibit the PI3K/AKT pathway to promote cytoprotective autophagy and inhibit cardiomyocyte apoptosis to improve myocardial fibrosis in diabetic rats. The results of this study are expected to provide new targets and intervention strategies for the prevention and treatment of diabetic cardiomyopathy.

How to stay attached-Formation of the ricefish plug and changes of internal reproductive structures in the pelvic brooding ricefish, Oryzias eversi Herder et al.(2012) (Beloniformes: Adrianichthyidae).

Teleost fishes show an enormous diversity of parental care, ranging from no care to viviparity with maternal provisioning of embryos. External brooders carry their developing eggs attached to their bodies. This requires the formation of novel morphological structures to support attachment. The pelvic brooding ricefish Oryzias eversi evolved such a structure, called the "plug."The plug anchors attaching filaments from the fertilized eggs inside the female reproductive system, allowing the female to carry the embryos until hatching. Using histological sections and µ-computed tomography scanning, we show that the plug is formed by several types of interstitial cells, blood capillaries, and collagen fibrils that encapsulate the end of the attaching filaments in the anterior part of the gonoduct. Even 15 days after the loss of the protruding attaching filaments, the plug remains. In addition, the developed plug contains multinucleated giant cells that are derived from fusing macrophages. We thus hypothesize that the ricefish plug, which is vital for egg attachment in O. eversi, evolved due to an inflammatory reaction. We assume that it forms similar to a foreign body granuloma, as a reaction to irritation or injury of the gonoduct epithelium by the attaching filaments. Our study further corroborates that pelvic brooding entails a complex set of adaptations to prolonged egg-carrying in the female reproductive system. During brooding, for instance, ovulation in the ovary is suppressed and the anterior part of the gonoduct is characterized by an intricate, recessed folding.

Protective effect of Esculetin on myocardial injury induced by doxorubicin

Objective: To study the protective effect of Esculetin on myocardial injury induced by doxorubicin and explore the mechanism of doxorubicin on myocardial injury in rats. Methods: Doxorubicin(2.5mg/kg) was injected intraperitoneally every other day for 6 times to establish a rat model of myocardial injury. The effects of different doses of Esculetin (10mg/kg & 20mg/kg) on serum myocardial enzymes and myocardial tissue were observed. Results: Doxorubicin significantly increased serum myocardial enzymes and the content of myocardial interstitial collagen fibers in mice. Different doses of Esculetin could reduce myocardial injury in a dose-dependent manner. Conclusion: Esculetin has a protective effect on myocardial injury induced by doxorubicin.

Effect of sacubitril/valsartan and empagliflozin on systemic inflammation and scar remodeling in a swine model of myocardial infarction

Abstract Background Angiotensin receptor neprilysin inhibitor (ARNI) and sodium glucose cotransporter 2 inhibitors (SGLT2i) lead to reduced cardiovascular death and hospitalization rates for heart failure, but mechanisms of action remain unclear. Purpose To evaluate the effect of ARNI and SLGT2i on cardiac function, systemic inflammation and scar remodeling in a porcine model of acute myocardial infarction (MI). Methods Thirty-three pigs (18 female, 15 male) with non-revascularized MI were randomized to receive treatment with beta-blocker (BB) only (BB group, n=8), empagliflozin + BB (SGLT2i group, n=8), sacubitril/valsartan + BB (ARNI group, n=9) or empagliflozin + sacubitril/valsartan + BB (SGLT2i + ARNI group, n=8) for 30 days post-MI. Cardiac function parameters were studied at 2- and 30-days post-MI by cardiac magnetic resonance imaging. The systemic immune response was analysed at baseline, 2-, 15- and 30-days post-MI to estimate 1) the absolute number of neutrophils and lymphocytes by FSC-A/SSC-A, 2) the circulating monocytes (CD172a+) and their phenotype according to CD73+, and CCR2+ expression. Animals were euthanized at 30 days, interstitial collagen and vascular density of the scar were quantified. Results Left ventricular ejection fraction (LVEF) and stoke volume (LVSV) improved in SGLT2i + ARNI group (P=0.02, P=0.002, respectively, 2 vs 30 days post-MI). Right ventricular ejection fraction (RVEF) and stroke volume (RVSV) improved in ARNI treatment arm (P=0.03; P=0.02, respectively, 2 vs 30 days post-MI). Significant increase in LV mass was only observed in BB group (P=0.02; 2 vs 30 days post-MI). SGLT2i and ARNI treatment prevented the acute increase in circulating leukocytes 2 days post-MI (P=0.0095; P=0.0091, respectively). Moreover, SGLT2i reduced the CCR2+ activated monocytes count at 15 days post-infarction (P=0.01). In contrast, the combined treatment increased the number of circulating monocytes (CD172a+) at 30 days (P=0.008). Reduced collagen I (P=0.04), and Col I/Col III ratio (P=0.02) was observed in ARNI group, and higher collagen III content (P=0.02) in SGLT2i group. Vascular density was significantly increased in SGLT2i + ARNI group (P=0.03). Conclusions SGLT2i modulates systemic inflammatory state. ARNI reduces myocardial fibrosis and improves right ventricular function. Combined treatment improves vascular density and left cardiac function in a post-MI porcine model. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Boehringer Ingelheim Spain, S.A, and Instituto de Salud Carlos III, CIBER Cardiovascular

Interstitial Collagen Loss, Myocardial Remodeling, and Function in Primary Mitral Regurgitation

Interstitial collagen loss and cardiomyocyte ultrastructural damage accounts for left ventricular (LV) sphericity and decrease in LV twist and circumferential strain. Normal LV diastolic function belies significantly abnormal left atrial (LA) function and early LV diastolic untwist rate. This underscores the complex interplay of LV and LA myocardial remodeling and function in the pathophysiology of primary mitral regurgitation. In this study, we connect LA function with LV systolic and diastolic myocardial remodeling and function using cardiac magnetic resonance tissue tagging in primary mitral regurgitation.

A Molecular Mechanism Study to Reveal Hirudin's Downregulation to PI3K/AKT Signaling Pathway through Decreasing PDGFRβ in Renal Fibrosis Treatment.

Chronic kidney disease (CKD) is identified as a widespread chronic progressive disease jeopardizing public health which characterized by gradually loss of renal function. However, there is no efficient therapy to prevail over this disease. Our study was attempting to reveal hirudin's regulation to renal fibrosis as well as the molecular mechanism. We built renal fibrosis models on both cell and animal levels, which were subsequently given with hirudin disposal; then, we performed the transwell assay to estimate the cells' migration and had our detection to relevant proteins with western blot and immunofluorescence. Finally, we commenced both the identification and the determination to the hirudin targeted proteins and its downstream signaling pathways with the methods of network pharmacology. And the results turned out that when it was compared with the model group, the group with hirudin addition came with the suppression in the migration of renal tubular epithelial cells NRK-52E and with a conspicuous decline in the expressions of fibronectin, N-cadherin, vimentin, TGF-β, and snail. After that, we predicted that there were 17 hirudin target points mainly involving in the PI3K-AKT signaling pathway. Our outcomes of the animal level demonstrated that the conditions of interstitial fibrosis, severe tubular dilatation or atrophy, inflammatory cell infiltration, and massive accumulation of interstitial collagen in the model group were withdrawn after the addition of hirudin. In addition, p-PDGFRβ, p-PI3K, and p-AKT protein expressions were significantly reduced, and the PI3K/AKT pathway was downregulated after hirudin treatment in the model group of NRK-52E cells and animals. Therefore, we had our conclusion that hirudin is capable of suppressing the PI3K-AKT signaling pathway as well as the EMT by decreasing PDGFRβ phosphorylation.

Effects of chronic intermittent hypoxia on atrial electrical remodeling in rats

The aim of this study was to investigate the effects of chronic intermittent hypoxia (CIH) on atrial electrical remodeling in Sprague-Dawley (SD) rats, which provide the explication for the mechanisms of CIH promoting atrial fibrillation (AF). Eighty SD rats were randomly divided into 2 groups: control group and CIH group (n=40). CIH rats were subjected to CIH 8 h/d for 30 days. After the echocardiography and hemodynamics examination, cardiac electrophysiological experiments, histological experiments, and molecular biological experiments were executed. AF susceptibility was measured by isolated heart electrophysiological experiments. Masson's trichrome stain was used to assess the degree of atrial fibrosis. The protein expression levels of sodium voltage-gated channel alpha subunit 5 (SCN5A/Nav1.5), calcium voltage-gated channel subunit alpha1 C (CACNA1C/Cav1.2) and potassium voltage-gated channel subfamily D member 3 (KCND3/Kv4.3) were measured by Western blot. In whole-cell patch clamp experiments, current clamp mode was used to record AP, and APD90 and APD50 were analyzed and compared between the two groups. In voltage clamp mode, INa, ICa-L, Ito and their kinetic parameters were recorded and compared between the two groups. Compared to the control rats, atrial interstitial collagen deposition (P＜0.01) and AF inducibility (P＜0.05) were increased in CIH rats, whereas the expression levels of Nav1.5, Cav1.2 and Kv4.3 were decreased (P＜0.05). APD90 and APD50 in CIH rats' atrial myocytes were longer than those of control rats, and CIH rats showed decreased current density of INa, ICa-L(P＜0.01) and Ito(P＜0.01). CIH-induced changes in the protein expression levels of ion channel subunits, current intensity, APD, and AF susceptibility, which may be the mechanisms of CIH promoting AF.

A case of patch granuloma annulare with CD68‐negative, CD163‐positive M2 macrophages infiltration in an interstitial pattern

Patch granuloma annulare is a rare type of granuloma annulare. Histopathologically, patch granuloma annulare shows interstitial infiltration of histiocytes. In our case, immunohistochemical analyses demonstrated CD68-negative, CD163-positive M2 macrophages infiltration in an interstitial pattern. Patch granuloma annulare (GA), a rare type of GA, is marked by asymptomatic and nonspecific skin discoloration that progresses slowly.1 Histopathologically, patch GA shows an interstitial pattern, whereas classic GA usually shows a palisading pattern, and both patterns are different in immunohistochemical findings.2 Here, we report a case of patch granuloma annulare with CD68-negative, CD163-positive M2 macrophages infiltration in an interstitial pattern. A 52-year-old Japanese woman presented with subtle, irritated erythematous-to-brown macules and patches that increased in size and number on the legs over one year. Physical examination showed well-demarcated and smooth macules, coalescing into large patches, which were distributed symmetrically and geographically on her extremities (Figure 1A,B). She had no chronic disease or medication use, and her laboratory tests were normal. Since topical corticosteroids and oral anti-allergic drugs had been ineffective, a skin biopsy was taken from her thigh. The histopathological result showed numerous histiocytes that infiltrated between interstitial collagen in the upper and middle dermis with some mucin deposition, which were particularly dense around vessels (Figure 1C–F). The characteristic skin lesions and pathological findings led to the diagnosis of patch granuloma annulare. The NB-UVB treatment was performed based on previous reports3 and almost all lesions faded away after 31 sessions of the exposure (total cumulative dose 19.4 J/cm2). In our case, histopathological and immunohistochemical analyses demonstrated an interstitial pattern of GA with negative CD68 and positive CD163 staining (Figure 1G). GA can be divided into two main types according to histopathology: palisading and interstitial patterns. The former shows focal palisaded granulomatous inflammation, and the latter shows interstitial infiltration of histiocytes. Classic GA often shows a palisading pattern, but it sometimes shows an interstitial pattern; in this situation, it is difficult to reach a diagnosis because of the inconsistency between histopathological findings and the characteristic skin rash. The finding that CD68 and CD163 staining corresponds with histiocytes of the palisading granuloma in the palisading pattern of GA is useful. In the interstitial pattern, CD163 staining corresponds with the histiocytes of the stroma, but CD68 staining is absent.2 CD68 is a pan-macrophage marker and CD163 is an M2 macrophage marker.4 It has been reported that the M1/M2 macrophage ratio reflects inflammatory activity based on the observation that M1 macrophages are pro-inflammatory and M2 macrophages are anti-inflammatory.5 These histopathological and immunohistochemical analyses may lead to the correct diagnosis and evaluation of clinical disease activity of GA. Patch GA is often asymptomatic or just mildly irritating and itchy, and the skin rash is inconspicuous and slowly enlarges. It often disappears spontaneously or in response to topical steroids, but it can also expand over a prolonged period, as was seen in the present case.6-8 The reason for such a mild condition may be related to the large proportion of CD163-positive anti-inflammatory M2 macrophages. In conclusion, patch GA is a rare form of GA characterized by a mild skin rash with an indolent course. Histopathological and immunohistochemical evaluation of the ratio of M1/M2 macrophages may contribute to understanding the disease activity. The authors declare no conflicts of interest. Approval of the research protocol: N/A. Informed consent: N/A. Registry and the Registration No. of the study/trial: N/A. Animal studies: N/A.

In Vivo Delivery of M0, M1, and M2 Macrophage Subtypes via Genipin-Cross-Linked Collagen Biotextile.

Developing strategies to regulate the immune response poses significant challenges with respect to the clinical translation of tissue-engineered scaffolds. Prominent advancements have been made relating to macrophage-based therapies and biomaterials. Macrophages exhibit the potential to influence healing trajectory, and predominance of particular subtypes during early onset of healing influences repair outcomes. This study evaluated short- and long-term healing response and postoperative mechanical properties of genipin-cross-linked, electrochemically aligned collagen biotextiles with comparative administration of M0, M1, and M2 subtypes. Irrespective of macrophage subtype seeded, all the groups demonstrated existence of M2 macrophages at both time points as typified by arginase and Ym-1 expressions, and distinct absence of M1 macrophages, as indicated by lack of inducible nitric oxide synthase (iNOS) and interleukin-1β expression in all the groups for both time points. M2 macrophage-seeded collagen biotextiles revealed promising host tissue responses, such as reduced fibrous capsule thickness and minimal granulation tissue formation. Furthermore, the M2-seeded group displayed more abundant interstitial collagen deposition following degradation of the collagen threads. M2 macrophage supplementation improved structural and mechanical properties at the tissue and cellular level as indicated by increased modulus and stiffness. This study demonstrates improved biomechanical and histological outcomes following incorporation of M2 macrophages into genipin-cross-linked collagen biotextiles for tissue repair and offers future strategies focused on connective tissue regeneration. Impact statement Macrophages exhibit significant plasticity with complex phenotypes ranging from proinflammatory (M1) to proregenerative (M2). They release cytokines and chemokines governing immunological stability, inflammation resolution, and tissue healing and regeneration. However, utilization of macrophages as therapeutic tools for tissue engineering remains limited. In this study, genipin-cross-linked collagen biotextiles were employed to deliver M0, M1, and M2 macrophages and evaluate tissue responses and postsurgical mechanical properties in vivo. M2-seeded collagen biotextiles showed reduced fibrous capsule and favorable healing response. These outcomes shed new light on designing tissue-engineered constructs that offer a novel cell-based therapeutic approach for applications requiring structural augmentation.