The Effect of Lymphangiogenesis in Transplant Arteriosclerosis.

BACKGROUND: Transplant arteriosclerosis is a major complication in long-term survivors of heart transplantation. Increased lymph flow from donor heart to host lymph nodes has been reported to play a role in transplant arteriosclerosis, but how lymphangiogenesis affects this process is unknown. METHODS: Vascular allografts were transplanted among various combinations of mice, including wild-type, Lyve1-CreERT2;R26-tdTomato, CAG-Cre-tdTomato, severe combined immune deficiency, Ccr2KO, Foxn1KO, and lghm/lghdKO mice. Whole-mount staining and 3-dimensional reconstruction identified lymphatic vessels within the grafted arteries. Lineage tracing strategies delineated the cellular origin of lymphatic endothelial cells. Adeno-associated viral vectors and a selective inhibitor were used to regulate lymphangiogenesis. RESULTS: Lymphangiogenesis within allograft vessels began at the anastomotic sites and extended from preexisting lymphatic vessels in the host. Tertiary lymphatic organs were identified in transplanted arteries at the anastomotic site and lymphatic vessels expressing CCL21 (chemokine [C-C motif] ligand 21) were associated with these immune structures. Fibroblasts in the vascular allografts released VEGF-C (vascular endothelial growth factor C), which stimulated lymphangiogenesis into the grafts. Inhibition of VEGF-C signaling inhibited lymphangiogenesis, neointima formation, and adventitial fibrosis of vascular allografts. These studies identified VEGF-C released from fibroblasts as a signal stimulating lymphangiogenesis extending from the host into the vascular allografts. CONCLUSIONS: Formation of lymphatic vessels plays a key role in the immune response to vascular transplantation. The inhibition of lymphangiogenesis may be a novel approach to prevent transplant arteriosclerosis.

Gut microbiome profile of Chinese hypertension patients with and without type 2 diabetes mellitus.

BACKGROUND: The coexistence of hypertension and type 2 diabetes mellitus (T2DM) may largely increase the risk for cardiovascular disease. However, there is no clear consensus on the association between hypertension and the risk of diabetes. Gut microbiota plays important roles in the development of hypertension and T2DM, but whether there is difference between hypertension patients with or without T2DM has not been explored yet. METHODS: We recruited 101 hypertension patients in this study (72 patients without T2DM named HT group and 29 patients with T2DM named HT-T2DM group). Their blood samples were collected for testing clinical characteristics and fecal samples were tested for bacterial DNA using 16 S ribosomal RNA gene sequencing targeting the V3 and V4 region. The data of 40 samples were downloaded from project PRJNA815750 as health control (HC group) in this study. The community composition and structure of the microbiome, taxonomic difference, co-occurrence network and functional enrichment were analyzed by alpha/beta diversity, LEfSe, Fruchterman Reingold's algorithm and PICRUSt2 functional analysis, respectively. RESULTS: Alpha and beta diversity analysis showed significant differences in microbial community richness and composition among the three groups. The HC group had a significantly higher Simpson index and a distinct microbiota community compared to the HT and HT-T2DM groups, as demonstrated by significant differences in unweighted and weighted UniFrac distances. The LEfSe analysis identified specific taxa that had significantly different abundance among the groups, such as Bacteroides uniformis, Blautia wexlerae, Alistipes putredinis, and Prevotella stercorea in the HC group, Prevotella copri and Phascolarctobacterium faecium in the HT group, and Klebsiella pneumoniae in the HT-T2DM group. Co-occurrence network analysis indicates that Prevotella copri, Mediterraneibacter gnavus, Alistipes onderdonkii and some unidentified species act as key nodes in the network. Differentially functional pathway identified by PICRUSt2 were concentrated in nutrition and energy metabolism, as well as the biosynthesis of other secondary metabolites. CONCLUSIONS: Our study found significant differences in microbial community richness, composition, and function among the healthy controls, hypertension patients with and without T2DM. Some specific taxa may explain this difference and serve as potential therapeutic targets for hypertension, T2DM, and their coexistence.

Nonbone Marrow CD34+ Cells Are Crucial for Endothelial Repair of Injured Artery.

[Figure: see text].

Compositional and functional changes in the salivary microbiota related to oral leukoplakia and oral squamous cell carcinoma: a case control study.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumours with increasing incidence, and oral leukoplakia (OLK) has a strong tendency to undergo malignant transformation. The oral microbiota may influence oral cancer progression, but the salivary bacterial composition and functional changes in OSCC and OLK have not been comprehensively elucidated. Therefore, we compared salivary bacteria in OLK and OSCC patients with healthy controls (HC). METHODS: Metagenomic sequencing was used to compare the bacterial composition and functional changes of 18 OSCC patients, 21 OLK patients and 21 HC. Spearman correlation was used to identify possible associations between functions and bacteria. RESULTS: Gemella was the most differentially enriched genus in OSCC. At the species level, Streptococcus sp. NPS 308, Streptococcus agalactiae, Gemella haemolysans and Gemella morbillorum were slightly increased in OLK and OSCC. Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that OSCC was mainly associated with metabolism functions, including lipid metabolism, carbohydrate metabolism and glycan biosynthesis and metabolism. The synthesis and degradation of ketone bodies, cysteine and methionine metabolism and glycerolipid metabolism differed significantly among the three groups, and were highest in OSCC and lowest in HC. And G. haemolysans was significantly associated with these selected metabolic pathways. CONCLUSIONS: Metagenomic analysis revealed significant differences in the salivary microbiota among OSCC, OLK and HC. Thus, salivary microbiota composition and functional changes may be associated with OSCC progression. Metabolism of nonessential amino acids such as cysteine and methionine in bacteria may play an important role in oral oncogenesis, and more studies of the mechanism between metabolisms of bacteria and oral oncogenesis are needed in the future.

The global prevalence of oral leukoplakia: a systematic review and meta-analysis from 1996 to 2022.

BACKGROUND: Oral leukoplakia(OLK) is a common oral potentially malignant disorder. The global prevalence of solely OLK was published in 2003, while the prevalence varied among different studies. In recent years, large-scale summary and definition-related analyses obtain insufficient attention. This study aimed to perform a systematic review of prevalence studies of oral leukoplakia and assess predisposing factors of its occurrence. METHODS: The search terms ("Oral leukoplakia" OR OLK OR leukoplakia) AND (prevalence OR incidence OR epidemiology) were searched in databases (Pubmed, Embase, Scopus, and Web of Science) for OLK studies published from January 1996 until December 2022. The estimated prevalence calculation and risk of bias analysis used STATA 16.0. RESULTS: We obtained 69 studies, including 1,263,028 participants, from 28 countries, and 6 continents. The prevalence was 1.39%, varying from 0.12 to 33.33%. The overall pooled estimated prevalence of OLK was 2.23% for population-based studies, 1.36% for clinic-based population studies, and 9.10% for specific populations. The pooled prevalence in different continents ranged from 0.33 to 11.74% with a statistical difference in the population-based calculation. The estimated prevalence of OLK was higher in males than in females. Those who smoked and consumed alcohol had a higher prevalence than those who did not. CONCLUSION: Combining data from 69 published studies, the prevalence of OLK was determined as 1.39% and the pooling estimated global prevalence was 3.41%. The prevalence was relatively consistent and stable across different continents and different definitions. A higher pooled estimated prevalence was found among males, those aged over 60 years old, smokers, and alcohol consumers. The results from the included studies in this systematic review revealed that the prevalence was relatively consistent and stable across various definitions and continents, which may help in developing global treatment and prevention strategies for oral leukoplakia.

Direct immunofluorescence analysis of oral Tzanck smears for pemphigus vulgaris: A diagnostic test.

BACKGROUND: Pemphigus vulgaris (PV) is a rare and potentially fatal autoimmune blistering disease. Direct immunofluorescence (DIF) and histopathological analysis are crucial methods for PV diagnosis, but oral tissue biopsy is difficult to perform because of the fragile characteristics of the oral mucosa. However, no well-designed diagnostic studies addressing the validity of DIF analysis of oral Tzanck smears for the diagnosis of PV exist. We aimed to design a diagnostic test based on DIF analysis combined with oral Tzanck smears and evaluate its diagnostic accuracy for PV. METHODS: We enrolled 81 patients with oral erosive lesions, of whom 41 patients had PV and 40 were non-PV controls. Oral Tzanck smears were obtained from oral mucosal lesions and observed under a fluorescence microscope after fixing and fluorescence staining. The diagnostic efficacy indexes including sensitivity, specificity, predictive value, Youden index, diagnostic odds ratio, and likelihood ratio were calculated. RESULTS: Of the 41 PV patients, 36 showed DIF-positive findings for oral Tzanck smears, and all 36 DIF-positive PV patients showed IgG and/or C3 deposition, with seven also showing IgA and/or IgM positivity. None of the non-PV controls showed DIF positivity. The sensitivity and specificity of DIF analysis with oral Tzanck smears were 87.80% and 100%, respectively. The area under the receiver operator characteristic curve (ROC) was 0.939, with the test demonstrating significantly high diagnostic efficacy. CONCLUSION: DIF analysis of oral Tzanck smears is a minimally invasive and easy-to-operate technique that can assist the rapid and accurate diagnosis of PV in dental clinic.

Circulating long noncoding RNA, GAS5, as a novel biomarker for patients with atrial fibrillation.

BACKGROUND: Circulating long noncoding RNA (lncRNA) plays a vital role in clinical disease diagnosis and prognosis. Here, we evaluate the role of a lncRNA, named growth arrest specific 5 (GAS5), in atrial fibrillation (AF). METHODS: Expression of GAS5 was measured by qRT-PCR. Diagnostic and prognostic values of GAS5 were assessed by the receiver operating characteristics curve (ROC), Kaplan-Meier (KM) and Cox regression analyses. RESULTS: A total of 173 participants were enrolled in this study. Circulating GAS5 expression was significantly down-regulated in AF patients. This change occurred prior to enlargement of the left atrial volume and was strongly associated with AF progression, which demonstrates the potential use of GAS5 as an early biomarker. The area under the ROC curve (AUC) was 0.858 (95% CI 0.789-0.926, P < .001). Seventy of the 85 AF patients received radiofrequency catheter ablation (RFCA), and 22 (31.4%) had relapsed by the 1-year follow-up. The KM analysis (log-rank test, P = .031) and multivariable Cox analysis (HR = 0.127, 95% CI 0.026-0.616; P = .01) revealed that GAS5 has a role in predicting recurrence after RFCA. CONCLUSION: Circulating lncRNA GAS5 is a potential biomarker for AF diagnosis and prognosis. Down-regulation of GAS5 occurs prior to left atrial enlargement and can be used for the prognosis of AF progression and recurrence.

Noncoding RNAs in Atrial Fibrillation: Current Status and Prospect.

Atrial fibrillation (AF) is an important cause of cardiovascular morbidity and mortality. Current therapies for AF are ineffective, mainly due to incomplete understanding of the pathogenesis of AF. Atrial remodeling contributes to the occurrence and progression of AF, but molecular mechanisms underlying AF remain unclear. Noncoding RNAs, including microRNAs, long noncoding RNAs and circular RNAs, are now considered to play an important role in the pathophysiology of AF. In this review, we summarize recent evidence supporting the role of noncoding RNAs in AF and highlight their diagnostic and prognostic applications as potential biomarkers and therapeutic strategies.

The deficiency of miR-214-3p exacerbates cardiac fibrosis via miR-214-3p/NLRC5 axis.

Cardiac fibrosis is a common pathological feature of many cardiovascular diseases. The regulatory mechanisms of miRNAs in cardiac fibrosis are still unknown. Previous studies on miR-214-3p in cardiac fibroblasts reached contradictory conclusions. Thus the role of miR-214-3p in cardiac fibrosis deserves further exploration. Using a combination of in vitro and in vivo studies, we identified miR-214-3p as an important regulator of cardiac fibrosis, and the proliferation and activation of cardiac fibroblasts. We demonstrated that the expression of miR-214-3p is down-regulated in TGF-ß1-treated myofibroblasts and transverse aortic constriction (TAC)-induced murine model. Additionally, miR-214-3pflox/flox/FSP1-cre mice and miR-214-3pwt/wt/FSP1-cre mice were subjected to TAC operation or sham operation, and the conditional knockout of miR-214-3p in cardiac fibroblasts aggravates TAC-induced cardiac fibrosis. In vitro, our results indicate that miR-214-3p is an important repressor for fibroblasts proliferation and fibroblast-to-myofibroblast transition by functionally targeting NOD-like receptor family CARD domain containing 5 (NLRC5). In conclusion, our findings show that the deficiency of miR-214-3p exacerbates cardiac fibrosis and reveal a novel miR-214-3p/NLRC5 axis in the regulation of cardiac fibrosis.

[Research progress on miR-21 in heart diseases].

Pathological processes such as myocardial apoptosis, cardiac hypertrophy, myocardial fibrosis, and cardiac electrical remodeling are involved in the development and progression of most cardiac diseases. MicroRNA-21 (miR-21) has been found to play an important role in heart diseases as a novel type of endogenous regulators, which can inhibit cardiomyocyte apoptosis, improve hypertension and cardiac hypertrophy, promote myocardial fibrosis and atrial electrical remodeling. In this review, we summarize the research progress on the function of miR-21 in heart diseases and its mechanism, and discuss its potential application in diagnosis and treatment of heart diseases.

Evaluation of the content quality of websites for recurrent aphthous ulcers and oral lichen planus.

BACKGROUND: The Internet is one of the most popular resources for people to obtain medical information; however, only a limited number of studies have reported the quality of the available health information related to oral mucosal diseases. The present study aimed to evaluate the quality of information on websites for recurrent aphthous ulcers (RAU) and oral lichen planus (OLP), in both Chinese and English. METHODS: Common search engines, BaiDu, Google, and Yahoo in Chinese; and Bing, Google, and Yahoo in English were used to identify websites providing content related to the oral mucosal diseases. The first 100 links for keywords "recurrent aphthous ulcers" and "oral lichen planus" were visited and content was downloaded within 24 h. Two separate trained researchers use the validated DISCERN rating instrument and JAMA benchmarks to evaluate the content. The rating scores were analyzed and the quality was assessed according to the scores and content of websites. RESULTS: A total of 145 websites for RAU and 128 of OLP were analyzed. Based on the DISCERN instrument, the quality of the content in websites for both diseases, whether in English or Chinese, was not high, generally scoring 2 to 3 (max. 5). Only 13 of the RAU websites and 21 of the OLP websites fulfilled the four criteria of the JAMA benchmarks. Generally, the scores of the English websites were higher than those of the Chinese websites. During the twelve searches, only four (Yahoo of RAU in Chinese, Bing and Yahoo of RAU in English, and Google of OLP in Chinese) showed moderate correlation between the website's ranking and their rating scores. People cannot obtain high quality medical information if they only look at the top ranked sites on the viewing lists. Websites belonging to universities or medical centers had relatively higher scores compared with the others. CONCLUSIONS: The quality of the content on websites relating to RAU and OLP in Chinese and English was moderate. More good quality websites and information are needed in the future.

Autophagy protects against senescence and apoptosis via the RAS-mitochondria in high-glucose-induced endothelial cells.

BACKGROUNDS: Autophagy is an important process in the pathogenesis of diabetes and plays a critical role in maintaining cellular homeostasis. However, the autophagic response and its mechanism in diabetic vascular endothelium remain unclear. METHODS AND RESULTS: We studied high-glucose-induced renin-angiotensin system (RAS)-mitochondrial damage and its effect on endothelial cells. With regard to therapeutics, we investigated the beneficial effect of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) against high-glucose-induced endothelial responses. High glucose activated RAS, enhanced mitochondrial damage and increased senescence, apoptosis and autophagic-responses in endothelial cells, and these effects were mimicked by using angiotensin II (Ang). The use of an ACEI or ARB, however, inhibited the negative effects of high glucose. Direct mitochondrial injury caused by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) resulted in similar negative effects of high glucose or Ang and abrogated the protective effects of an ACEI or ARB. Additionally, by impairing autophagy, high-glucose-induced senescence and apoptosis were accelerated and the ACEI- or ARB-mediated beneficial effects were abolished. Furthermore, increases in FragEL™ DNA Fragmentation (TUNEL)-positive cells, ß-galactosidase activation and the expression of autophagic biomarkers were revealed in diabetic patients and rats, and the treatment with an ACEI or ARB decreased these responses. CONCLUSIONS: These data suggest that autophagy protects against senescence and apoptosis via RAS-mitochondria in high-glucose-induced endothelial cells.

Possible involvement of fibrocytes in atrial fibrosis in patients with chronic atrial fibrillation.

BACKGROUND: Chronic atrial fibrillation (AF) is characterized by a remodeling process with prominent atrial fibrosis. Fibrocytes, a bone marrow-derived population of fibroblast-like cells, have been placed at the center of a number of fibrosing conditions. The purpose of this study was to evaluate the contribution of fibrocytes to atrial fibrosis in patients with chronic AF and the possible mechanisms. METHODS AND RESULTS: We enrolled 22 consecutive valvular heart disease patients with chronic AF (>6 months: CAF group) and 15 valvular heart disease patients in sinus rhythm served as controls (SR group). Left atrial tissue samples were obtained during cardiac surgery. The infiltration of fibrocytes into the atrial interstitium was observed by confocal microscopy. The number of atrial fibrocytes was approximately three-fold higher in the CAF group compared with the SR controls, and positively correlated with both the atrial collagen volume fraction (r=0.713; P=0.0002) and the left atrial volume index (r=0.631; P=0.002). In the peripheral blood samples collected before the operation, approximately 2.5-fold higher percentage of circulating fibrocytes was identified in the CAF group. These fibrocytes showed a stronger proliferative capacity (≍2.5-fold) and higher level expression of collagen I and α-SMA (≍2-fold and 4-fold, respectively) compared with the SR controls. CONCLUSIONS: The results suggested that fibrocytes may be involved in atrial fibrosis in chronic AF through enhanced profibrotic characteristics.

Efficacy and side effects of pembrolizumab plus chemotherapy vs. chemotherapy alone in patients with advanced gastric or gastroesophageal junction adenocarcinoma: A meta­analysis.

Recently, the treatment plan of pembrolizumab plus chemotherapy was regarded as a promising treatment for patients with advanced gastric cancer or gastroesophageal junction adenocarcinoma (GC/GEJC). However, the efficacy and side effects of pembrolizumab plus chemotherapy still lack evidence-based medical evidence to support. Therefore, a meta-analysis was conducted to evaluate the hot issue. By searching PubMed, EMBASE, Cochrane Library, Web of Science, any randomized clinical studies of pembrolizumab plus chemotherapy versus chemotherapy in patients with advanced GC/GEJC met the inclusion criteria were included. The quality of the literature was evaluated and the data was extracted. A correlative software was also used to analyze the data and to draw a conclusion. After screening 14,015 studies, four studies were eligible for the meta-analysis. Compared with chemotherapy alone group, the overall survival (OS) rate was significantly longer. In programmed cell death ligand 1 (PD-L1) combined positive score (CPS) ≥1 subgroup and PD-L1 CPS ≥10 subgroup analyses, the results showed that the response rate (RR) and complete response rate (CR) were both higher in pembrolizumab plus chemotherapy group compared with chemotherapy alone group. There were not significant differences in the CR, the treatment-related adverse events, succumbed to drug-related events and succumbed to immune-mediated events between the two groups. However, the effect events such as the treatment-related adverse events led to discontinuation, the 3-5 treatment-related adverse events and the immune-mediated adverse events and infusion reactions were more common in pembrolizumab plus chemotherapy group. In conclusion, the current meta-analysis revealed that, in treating advanced GC/GEJC, pembrolizumab plus chemotherapy had improved therapeutic efficacies than chemotherapy alone, as evidenced by the significantly longer OS. Furthermore, the patients in PD-L1 CPS ≥1 subgroup and PD-L1 CPS ≥10 subgroup appeared to benefit from pembrolizumab plus chemotherapy treatment because of higher RR and CR. However, side effects such as the treatment-related adverse events leading to discontinuation, the 3-5 treatment-related adverse events, and immune-mediated adverse events and infusion reactions deserved more attention.

Mitochondrial Dysfunction: A Roadmap for Understanding and Tackling Cardiovascular Aging.

Cardiovascular aging is a progressive remodeling process constituting a variety of cellular and molecular alterations that are closely linked to mitochondrial dysfunction. Therefore, gaining a deeper understanding of the changes in mitochondrial function during cardiovascular aging is crucial for preventing cardiovascular diseases. Cardiac aging is accompanied by fibrosis, cardiomyocyte hypertrophy, metabolic changes, and infiltration of immune cells, collectively contributing to the overall remodeling of the heart. Similarly, during vascular aging, there is a profound remodeling of blood vessel structure. These remodeling present damage to endothelial cells, increased vascular stiffness, impaired formation of new blood vessels (angiogenesis), the development of arteriosclerosis, and chronic vascular inflammation. This review underscores the role of mitochondrial dysfunction in cardiac aging, exploring its impact on fibrosis and myocardial alterations, metabolic remodeling, immune response remodeling, as well as in vascular aging in the heart. Additionally, we emphasize the significance of mitochondria-targeted therapies in preventing cardiovascular diseases in the elderly.

Remote Ischemic Conditioning Mediates Cardio-protection After Myocardial Ischemia/Reperfusion Injury by Reducing 4-HNE Levels and Regulating Autophagy via the ALDH2/SIRT3/HIF1α Signaling Pathway.

Remote ischemic conditioning (RIC) can be effectively applied for cardio-protection. Here, to clarify whether RIC exerts myocardial protection via aldehyde dehydrogenase 2 (ALDH2), we established a myocardial ischemia/reperfusion (I/R) model in C57BL/6 and ALDH2 knockout (ALDH2-KO) mice and treated them with RIC. Echocardiography and single-cell contraction experiments showed that RIC significantly improved myocardial function and alleviated I/R injury in C57BL/6 mice but did not exhibit its cardioprotective effects in ALDH2-KO mice. TUNEL, Evan's blue/triphenyl tetrazolium chloride, and reactive oxygen species (ROS) assays showed that RIC's effect on reducing myocardial cell apoptosis, myocardial infarction area, and ROS levels was insignificant in ALDH2-KO mice. Our results showed that RIC could increase ALDH2 protein levels, activate sirtuin 3 (SIRT3)/hypoxia-inducible factor 1-alpha (HIF1α), inhibit autophagy, and exert myocardial protection. This study revealed that RIC could exert myocardial protection via the ALDH2/SIRT3/HIF1α signaling pathway by reducing 4-HNE secretion.

Fibroblasts facilitate lymphatic vessel formation in transplanted heart.

Rationale: Lymphangiogenesis plays a critical role in the transplanted heart. The remodeling of lymphatics in the transplanted heart and the source of newly formed lymphatic vessels are still controversial, especially the mechanism of lymphangiogenesis remains limited. Methods: Heart transplantation was performed among BALB/c, C57BL/6J, Cag-Cre, Lyve1-CreERT2;Rosa26-tdTomato and Postn(2A-CreERT2-wpre-pA)1;Rosa26-DTA mice. scRNA-seq, Elisa assay, Western blotting, Q-PCR and immunohistochemical staining were used to identify the cells and cell-cell communications of allograft heart. Cell depletion was applied to in vivo and in vitro experiments. Whole-mount staining and three-dimensional reconstruction depicted the cell distribution within transparent transplanted heart. Results: Genetic lineage tracing mice and scRNA-seq analysis have revealed that these newly formed lymphatic vessels mainly originate from recipient LYVE1+ cells. It was found that LECs primarily interact with activated fibroblasts. Inhibition of lymphatic vessel formation using a VEGFR3 inhibitor resulted in a decreased survival time of transplanted hearts. Furthermore, when activated fibroblasts were ablated in transplanted hearts, there was a significant suppression of lymphatic vessel generation, leading to earlier graft failure. Additional investigations have shown that activated fibroblasts promote tube formation of LECs primarily through the activation of various signaling pathways, including VEGFD/VEGFR3, MDK/NCL, and SEMA3C/NRP2. Interestingly, knockdown of VEGFD and MDK in activated fibroblasts impaired cardiac lymphangiogenesis after heart transplantation. Conclusions: Our study indicates that cardiac lymphangiogenesis primarily originates from recipient cells, and activated fibroblasts play a crucial role in facilitating the generation of lymphatic vessels after heart transplantation. These findings provide valuable insights into potential therapeutic targets for enhancing graft survival.

Low molecular weight heparin inhibits circulating fibrocytes differentiation by modulating neuronal nitric oxide synthase and TGF-ß1/Smad pathway.

BACKGROUND/AIMS: Circulating fibrocytes (CFs) have been placed at the center of a number of fibrosing conditions. Recently, attention has been drawn to the non-anticoagulant activities of low molecular weight heparin (LH), especially its anti-fibrotic effects. The purpose of this study was to investigate the effects of LH on CFs differentiation and possible underlying mechanisms. METHODS/RESULTS: CFs were cultured from human peripheral blood mononuclear cells and identified by dual-immunofluorescence staining. Incubation with LH inhibited CFs trans-differentiation by upregulating CD34 and downregulating pro-Collagen I and a-SMA in a concentration- and time-dependent manner, all of which were detected by flow cytometry. Similar effects were observed after incubation with L-NAME, an inhibitor of NOS. NO production was measured by Griess methods and markedly decreased in CFs treated with LH. Three NOS isoforms were assessed by western blot and nNOS was the predominant isoform involved in this process. Additionally, LH and L-NAME had similar down-regulating effects on the expression of TGF-ß1 and pSmad2/3, which indicated that TGF-ß/Smad pathway might be a downstream signaling of nNOS/NO during LH treatment. CONCLUSION: These results suggested that LH could exhibit anti-fibrotic effects by inhibiting CFs transdifferentiation, in which the involvement of nNOS/NO and TGF-ß/Smad pathway were identified.

Angiotensin-(1-7) suppresses the number and function of the circulating fibrocytes by upregulating endothelial nitric oxide synthase expression.

There is growing evidence suggesting that circulating fibrocytes (CFs) play a pivotal role in tissue repair and fibrosis. In contrast, in recent studies, angiotensin-(1-7) [Ang-(1-7)] has been shown to antagonize fibrosis. The purpose of this study was to examine the direct effect of Ang-(1-7) on CFs. Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation. Using laser scanning confocal microscopy, CFs were identified as adherent cells that stained positive for both CD34 and collagen-I. After 14 days of culture, CFs were stimulated with Ang-(1-7) at concentrations of 10 nM, 100 nM, 1 µM or 10 µM, in the absence and presence of pretreatment with A-779, N(G)-nitro-L-arginine methyl ester (L-NAME) or both, for 24, 48 or 72 h. The number of cells, cellular proliferation, and level of apoptosis were determined by hematoxylin and eosin staining, the Cell Counting Kit-8 (CCK8) assay and the annexin V/propidium iodide binding assay, respectively. The collagen content of CFs was measured by the concentration of hydroxyproline, which was detected using the enzymatic digestion method. The expression of endothelial nitric oxide synthase (eNOS) was assayed by western Blot analysis, while nitric oxide (NO) generation was detected using the Griess method. We found that Ang-(1-7) increases apoptosis and eNOS/NO production in CFs. In addition, Ang-(1-7) decreases the number, proliferative capacity and collagen-secretion of CFs in a concentration- and time-dependent manner. These data suggest that Ang-(1-7) suppresses the both the number and function of CFs possibly by increasing eNOS/NO production in the CFs.