Wuxi Ninth People's Hospital

Rationale: Use of ACEIs (angiotensin-converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers) is a major concern for clinicians treating coronavirus disease 2019 (COVID-19) in patients with hypertension. Objective: To determine the association between in-hospital use of ACEI/ARB and all-cause mortality in patients with hypertension and hospitalized due to COVID-19. Methods and Results: This retrospective, multi-center study included 1128 adult patients with hypertension diagnosed with COVID-19, including 188 taking ACEI/ARB (ACEI/ARB group; median age 64 [interquartile range, 55–68] years; 53.2% men) and 940 without using ACEI/ARB (non-ACEI/ARB group; median age 64 [interquartile range 57–69]; 53.5% men), who were admitted to 9 hospitals in Hubei Province, China from December 31, 2019 to February 20, 2020. In mixed-effect Cox model treating site as a random effect, after adjusting for age, gender, comorbidities, and in-hospital medications, the detected risk for all-cause mortality was lower in the ACEI/ARB group versus the non-ACEI/ARB group (adjusted hazard ratio, 0.42 [95% CI, 0.19–0.92]; P =0.03). In a propensity score-matched analysis followed by adjusting imbalanced variables in mixed-effect Cox model, the results consistently demonstrated lower risk of COVID-19 mortality in patients who received ACEI/ARB versus those who did not receive ACEI/ARB (adjusted hazard ratio, 0.37 [95% CI, 0.15–0.89]; P =0.03). Further subgroup propensity score-matched analysis indicated that, compared with use of other antihypertensive drugs, ACEI/ARB was also associated with decreased mortality (adjusted hazard ratio, 0.30 [95% CI, 0.12–0.70]; P =0.01) in patients with COVID-19 and coexisting hypertension. Conclusions: Among hospitalized patients with COVID-19 and coexisting hypertension, inpatient use of ACEI/ARB was associated with lower risk of all-cause mortality compared with ACEI/ARB nonusers. While study interpretation needs to consider the potential for residual confounders, it is unlikely that in-hospital use of ACEI/ARB was associated with an increased mortality risk.

Abstract Rationale The coronavirus disease (COVID-19) pandemic is now a global health concern. Objectives We compared the clinical characteristics, laboratory examinations, computed tomography images, and treatments of patients with COVID-19 from three different cities in China. Methods A total of 476 patients were recruited from January 1, 2020, to February 15, 2020, at three hospitals in Wuhan, Shanghai, and Anhui. The patients were divided into four groups according to age and into three groups (moderate, severe, and critical) according to the fifth edition of the Guidelines on the Diagnosis and Treatment of COVID-19 issued by the National Health Commission of China. Measurements and Main Results The incidence of comorbidities was higher in the severe (46.3%) and critical (67.1%) groups than in the moderate group (37.8%). More patients were taking angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers in the moderate group than in the severe and critical groups. More patients had multiple lung lobe involvement and pleural effusion in the critical group than in the moderate group. More patients received antiviral agents within the first 4 days in the moderate group than in the severe group, and more patients received antibiotics and corticosteroids in the critical and severe groups. Patients >75 years old had a significantly lower survival rate than younger patients. Conclusions Multiple organ dysfunction and impaired immune function were the typical characteristics of patients with severe or critical illness. There was a significant difference in the use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers among patients with different severities of disease. Involvement of multiple lung lobes and pleural effusion were associated with the severity of COVID-19. Advanced age (≥75 yr) was a risk factor for mortality.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic globally.1 As of 18 April, it had infected over 2 million people worldwide. Recently, a study reported that the median duration of SARS-CoV-2 RNA shedding in 113 patients was 17 days from symptom onset in Zhejiang and Shenzhen centers.2 In Wuhan, where the coronavirus disease 2019 (COVID-19) first started, the duration of the infection and clinical characteristics of the patients remain unknown. Herein, we studied the clinical characteristics of 36 confirmed COVID-19 patients who continued to shed viral RNA for longer than 30 days. The 378 patients diagnosed with COVID-19 based on the New Coronavirus Pneumonia Prevention and Control Program (5th edition) published by the National Health Commission of China,3 were admitted to the 4th Infectious Disease Department in Wuhan Huoshenshan Hospital from 11 February to 11 April 2020. We searched their electronic medical records and found that their duration of SARS-CoV-2 RNA shedding was longer than 30 days. The 36 patients were tested for SARS-CoV-2 using the real-time reverse transcriptase polymerase chain reaction (RT-PCR) test, on samples collected from the respiratory tract using the Chinese Center for Disease Control and Prevention (CDC) recommended Kit (BioGerm, Shanghai, China), and following World Health Organization (WHO) guidelines for qRT-PCR.4 The median age of the patients was 57.5 years (interquartile range [IQR] 52-65) and 11.1% of them were below 40 years old. Among the patients, 13 (36.1%) were females. Most patients had associated comorbidities (22 [61.1%]), including cardiovascular diseases like hypertension and coronary heart disease (16 [44.4%]), metabolic diseases like diabetes and gout (7 [19.4%]), and chronic respiratory diseases like chronic bronchitis (3 [8.3%]). In addition, some patients had more than one comorbidity. On admission, 33 (91.7%) and 3 (8.3%) patients had mild and severe COVID-19, respectively. A recent report by Yang et al5 described a patient whose clinical course lasted for more than 2 months. However, in our study, prolonged viral RNA shedding even after symptomatic relief was not rare, and the median duration of viral RNA shedding was 53.5 days (IQR 47.75-60.5). The longest duration of viral RNA shedding could be 83 days. We divided the patients into two groups: early-onset group whose symptoms started before 1 February 2020 and late-onset group whose symptoms started after 1 February 2020. Compared to the late-onset group, the patients in the early-onset group had longer durations of viral shedding and more severe illnesses. SARS-CoV-2 immunoglobulin M (IgM) and IgG antibodies were analyzed by chemiluminescent immunoassay following the protocol of the manufacture (Shenzhen Yahuilong Biotechnology Co, Ltd). Although the IgM level reached its peak as in SARS-CoV,6 it could remain persistently high in these patients even until the ninth week (Figure 1). The high levels of IgM indicated the duration of viral infection and may be related to the prolonged viral RNA shedding. Most of the patients received antiviral therapy at the beginning of the infection for at least 1 week, including arbidol (34 [91.9%]), ribavirin (1 [2.7%]), and remdesivir (2 [5.4%]). In addition, 17 patients received antiviral treatment again at the final stage, due to the prolonged viral RNA shedding. Among them, 13 patients received chloroquine phosphate therapy and 4 patients received chloroquine and favipiravir combined therapy for at least 5 days until their nucleic acid test turned negative. Although the mortality caused by COVID-19 is lower than that by SARS and MERS, the infectivity and transmissibility of the virus is higher.7 A definite and an effective treatment for the disease is still under investigation and the targeted vaccine is undergoing clinical trials. The most effective way to control the disease spread is by the isolation of patients. According to our results, prolonged viral RNA shedding is not a rare phenomenon regardless of symptomatic relief. Moreover, a study by Xiao et al8 showed a high rate of patients got positive viral RNA nucleic acid tests again after two consecutive negative tests. Therefore, a longer observation period for COVID-19 patients is necessary independent of symptomatic relief and even when the patients have met the discharge standard—two consecutive negative nucleic acid tests. The IgM titer test may be an effective supplementary test. A study reported that viral RNA shedding from asymptomatic patients was similar to that of other patients.9 And Jiang et al10 even described an asymptomatic patient whose viral detection was positive in stools for 42 days but persistent negative in throat samples. Therefore, further studies are necessary to investigate the infectivity of these prolonged-RNA-shedding patients at the later stage of the clinical course and their viral RNA shedding in stools, and the use of some antiviral drugs may be effective to eliminate the virus. The authors declare that there are no conflict of interests.

Anemia commonly aggravates the severity of respiratory diseases, whereas thus far, few studies have elucidated the impact of anemia on coronavirus disease 2019 (COVID-19). The aim of this study was to evaluate the clinical characteristics of patients with anemia, and to further explore the relationship between anemia and the severity of COVID-19. In this single-center, retrospective, observational study, a total of 222 confirmed patients admitted to Wuhan Ninth Hospital from 1 December 2019 to 20 March 2020 were recruited, including 79 patients with anemia and 143 patients without anemia. Clinical characteristics, laboratory findings, disease progression and prognosis were collected and analyzed. Risk factors associated with the severe illness in COVID-19 were established by univariable and multivariable logistic regression models. In our cohort, compared to patients without anemia, patients with anemia were more likely to have one or more comorbidities and severe COVID-19 illness. More patients demonstrated elevated levels of C-reactive protein (CRP), procalcitonin (PCT) and creatinine in anemia group. Levels of erythrocyte sedimentation rate, D-dimer, myoglobin, T-pro brain natriuretic peptide (T-pro-BNP) and urea nitrogen in patients with anemia were significantly higher than those without. In addition, the proportion of patients with dyspnea, elevated CRP, and PCT was positively associated with the severity of anemia. The odd ratio of anemia related to the severe condition of COVID-19 was 3.47 (95% confidence interval [CI]: 1.02-11.75; P = .046) and 3.77 (95% CI: 1.33-10.71; P = .013) after adjustment for baseline date and laboratory indices, respectively. Anemia is an independent risk factor associated with the severe illness of COVID-19, and healthcare professionals should be more sensitive to the hemoglobin levels of COVID-19 patients on admission. Awareness of anemia as a risk factor for COVID-19 was of great significance.

OBJECTIVE: This study aimed to estimate the global burden of atrial fibrillation/atrial flutter (AF/AFL). METHODS: We retrieved data from the Global Health Data Exchange query tool and estimated the age-standardised rates (ASRs) of prevalence, incidence and disability-adjusted life-years (DALYs) of AF/AFL, as well as the population attributable fraction (PAF) of risk factors contributing to DALYs. ASRs and sociodemographic index (SDI) were assessed using Pearson's correlation coefficients. RESULTS: In 2017, there were 37.6 million (95% uncertainty interval (UI) 32.5 to 42.6 million) individuals with AF/AFL globally. The prevalence rates increased with increased SDI values in most regions for all years. Men had a higher prevalence than women across all regions except for China. From 1990 to 2017, global prevalence rate decreased by 5.08% (95% UI -6.24% to -3.82%), with the largest decrease noted in the region with high SDI values. The global DALYs rate declined by 2.53% (95% UI -4.16 to -0.29). PAF of elevated systolic blood pressure for attributable DALYs accounted for the highest percentage, followed by high body mass index, alcohol use, high-sodium diet, smoking and lead exposure. CONCLUSIONS: Although the ASRs of prevalence, incidence and DALYs decreased from 1990 to 2017, the absolute number of patients with AF/AFL, annual number of new AF/AFL cases and DALYs lost due to AF/AFL increased. This indicates that the burden of AF/AFL is likely to remain high. Systematic surveillance is needed to better identify and manage AF/AFL so as to prevent its various risk factors and complications.

Stem cell therapy based on advanced biomaterials provides a promising strategy in bone tissue engineering. Nevertheless, guided bone regeneration which fulfills the criteria in terms of biomechanics, biodegradability and bioactivity is highly appealing but challenging. Inspired by the superior double-network (DN) structure, herein, a biodegradable hybrid DN hydrogel is proposed to promote in situ bone regeneration. The DN hydrogel is constructed by interspersing a methacrylated gelatin (GelMA) network into a well-defined nanocomposite (NC) hydrogel consisting of methacrylated chitosan (CSMA) and polyhedral oligomeric silsesquioxane (POSS) via a two-step photo-crosslinking process. The hybrid DN hydrogel has the following advantageous characteristics: (i) it exhibits enhanced stiffness and toughness benefiting from the inorganic POSS units and unique energy dissipation; (ii) naturally occurring biomacromolecules (chitosan and gelatin) as the hydrogel framework result in an appropriate biodegradation behavior, which can be replaced by newly formed tissues; (iii) it preferentially guides mesenchymal stem cells (MSCs) toward osteogenic differentiation in vitro by detecting the elevated levels of enzyme activity and calcium deposition along with the up-regulated osteogenesis-related genes and proteins; and (iv) accelerated in situ bone regeneration is observed after implanting MSC-loaded hydrogels into rat calvarial defects. Therefore, we provide a new insight to develop functional hydrogels for triggering specific cellular responses toward stem cell therapy and bone-related tissue engineering.

Shape memory polymers (SMPs) have exhibited great potential in biomedical applications. However, the typical triggers of shape recovery such as heat, UV light, and electricity may be harmful to humans. Accordingly, water-responsive SMPs have become significant, especially for in vivo applications, due to the intrinsic biocompatibility and ready availability of water. However, the reported water-responsive SMPs are limited and relatively complicated. Here, we design a new water-responsive SMP, poly(butanetetrol fumarate) (PBF); the properties of PBF could be modulated by curing. The cured PBF scaffolds exhibited high shape recovery and fixity rates (>95%). PBF showed good biodegradability, and it could support the attachment, viability and alkaline phosphatase activity of osteoblasts. Furthermore, PBF could be readily functionalized via pendant hydroxyl groups, which was demonstrated by the immobilization and controlled release of bone morphogenetic protein 2. We expect that PBF will be useful for various biomedical applications including water-responsive scaffolds, sensors or actuators.

: ACP5/TRAP: acid phosphatase 5, tartrate resistant; ATP6V0D2: ATPase, H+ transporting, lysosomal V0 subunit D2; BCL2: B cell leukemia/lymphoma 2; BECN1: beclin 1, autophagy related; BMs: bone marrow cells; CTSK: cathepsin K; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MMP9: matrix metallopeptidase 9; OVX: oophorectomy; RUNX1: runt related transcription factor 1; SOCS3: suppressor of cytokine signaling 3; SPI1/PU.1: Spi-1 proto-oncogene; TNFSF11/RANKL: tumor necrosis factor (ligand) superfamily, member 11; TET2: tet methylcytosine dioxygenase 2.

Bioactive glass nanoparticles (BGN) are promising materials for a number of biomedical applications.

Bone regeneration under osteoporotic conditions with impaired angiogenesis, osteogenesis and remodeling represents a great challenge. In the present study, the effects of quercetin on proliferation, osteogenic differentiation and angiogenic factor secretion as well as on the osteoclastogenic factor secretion of ovariectomized (OVX) rat bone marrow-derived mesenchymal stem cells (rBMSCs) were first evaluated in vitro. The role of mitogen-activated protein kinase (MAPK) signaling pathways and the protein kinase B (AKT) signaling pathway in these processes was also investigated. Finally, hydroxyapatite (HA) bioceramic microspheres with a micro-nano hybrid surface (nHA bioceramic microspheres) were fabricated and used as drug delivery carriers of quercetin, and the ability to induce osteogenesis and angiogenesis in vivo was confirmed in an OVX rat critical-sized femur defect model. In vitro studies showed that quercetin significantly promoted cell proliferation, ALP activity and the expression of osteogenic and angiogenic factors of OVX rBMSCs as well as inhibited the expression of receptor activator of nuclear factor-κB ligand (RANKL) in a dose-dependent manner, with a concentration of 1 μM yielding the greatest effect. Moreover, the activation of the extracellular signal-regulated protein kinase (ERK), p38 and AKT signaling pathways was observed in quercetin-treated OVX rBMSCs, and the crosstalk among these signaling pathways was evident. Furthermore, the nHA bioceramic microspheres could efficiently release quercetin in a sustained manner, and quercetin loaded in the nHA bioceramic microspheres could promote new bone formation and blood vessel formation in vivo. The present study revealed that quercetin could promote osteogenesis and angiogenesis while inhibiting osteoclastogenesis both in vitro and in vivo under osteoporotic conditions. Moreover, HA bioceramic microspheres with a micro-nano hybrid surface could act as injectable drug delivery carriers of quercetin and could be applied for osteoporotic bone regeneration.

Background and Object. There is a growing body of evidence highlighting the significant role of gut microbiota in various neurological and psychiatric disorders. We performed an evidence mapping to review the association between different microbiota and these disorders and assessed the strength of evidence for these associations. Methods. We searched PubMed, Cochrane Library, and Epistemonikos to identify systematic reviews and meta-analysis (SRs). We searched for neurological diseases and psychiatric disorders, including Alzheimer’s disease (AD), attention deficit hyperactivity disorder (ADHD), amyotrophic lateral sclerosis (ALS), autism spectrum disorder (ASD), anorexia nervosa (AN), bipolar disorder (BD), eating disorder (ED), generalized anxiety disorder (GAD), major depressive disorder (MDD), multiple sclerosis (MS), obsessive compulsive disorder (OCD), Parkinson’s disease (PD), posttraumatic stress disorder (PTSD), spinal cord injury (SCI), schizophrenia, and stroke. We used A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) to evaluate the quality of included SRs. We also created an evidence map showing the role of gut microbiota in neurological diseases and the certainty of the evidence. Results. In total, 42 studies were included in this evidence mapping. Most findings were obtained from observational studies. According to the AMSTAR-2 assessment, 21 SRs scored “critically low” in terms of methodological quality, 16 SR scored “low,” and 5 SR scored “moderate.” A total of 15 diseases have been investigated for the potential association between gut microbiome alpha diversity and disease, with the Shannon index and Simpson index being the most widely studied. A total of 12 diseases were investigated for potential link between beta diversity and disease. At the phylum level, Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia were more researched. At the genus level, Prevotella, Coprococcus, Parabacteroides, Phascolarctobacterium, Escherichia Shigella, Alistipes, Sutteralla, Veillonella, Odoribacter, Faecalibacterium, Bacteroides, Bifidobacterium, Dialister, and Blautia were more researched. Some diseases have been found to have specific flora changes, and some diseases have been found to have common intestinal microbiological changes. Conclusion. We found varied levels of evidence for the associations between gut microbiota and neurological diseases; some gut microbiota increased the risk of neurological diseases, whereas others showed evidence of benefit that gut microbiota might be promising therapeutic targets for such diseases.

The musculoskeletal system supports the movement of the entire body and provides blood production while acting as an endocrine organ. With aging, the balance of bone homeostasis is disrupted, leading to bone loss and degenerative diseases, such as osteoporosis, osteoarthritis, and intervertebral disc degeneration. Skeletal diseases have a profound impact on the motor and cognitive abilities of the elderly, thus creating a major challenge for both global health and the economy. Cellular senescence is caused by various genotoxic stressors and results in permanent cell cycle arrest, which is considered to be the underlying mechanism of aging. During aging, senescent cells (SnCs) tend to aggregate in the bone and trigger chronic inflammation by releasing senescence-associated secretory phenotypic factors. Multiple signalling pathways are involved in regulating cellular senescence in bone and bone marrow microenvironments. Targeted SnCs alleviate age-related degenerative diseases. However, the association between senescence and age-related diseases remains unclear. This review summarises the fundamental role of senescence in age-related skeletal diseases, highlights the signalling pathways that mediate senescence, and discusses potential therapeutic strategies for targeting SnCs.

The adverse effect of acidosis on the skeletal system has been recognized for almost a century. Although the underlying mechanism has not been fully elucidated, it appears that acidosis acts as a general stimulator of osteoclasts derived from bone marrow precursors cells and enhances osteoclastic resorption. Prior work suggests that acidosis plays a significant role in osteoclasts formation and activation via up-regulating various genes responsible for its adhesion, migration, survival and bone matrix degradation. Understanding the role of acidosis in osteoclast biology may lead to development of novel therapeutic approaches for the treatment of diseases related to low bone mass. In this review, we aim to discuss the recent investigations into the effects of acidosis in osteoclast biology and the acid-sensing molecular mechanism.

BACKGROUND: Macrophage in the spinal cord injury (SCI) area imparts a chronic pro-inflammation effect that challenges the recovery of SCI. Previously, endothelial progenitor cell-produced exosomes (EPC-EXOs) have been noticed to facilitate revascularization and inflammation control after SCI. However, their effects on macrophage polarization remained unclear. This study aimed to investigate the EPC-EXOs' role in macrophage polarization and reveal its underlying mechanism. METHODS: We extracted the macrophages and EPC from the bone marrow suspension of C57BL/L mice by centrifugation. After cell identification, the EPC-EXOs were collected by ultra-high-speed centrifugation and exosome extraction kits and identified by transmission electron microscopy and nanoparticle tracking analysis. Then, macrophages were cultured with EPC-EXOs in different concentrations. We labeled the exosome to confirm its internalization by macrophage and detected the macrophage polarization marker level both in vitro and in vivo. We further estimated EPC-EXOs' protective effects on SCI by mice spinal cord tissue H&E staining and motor behavior evaluation. Finally, we performed RT-qPCR to identify the upregulated miRNA in EPC-EXOs and manipulate its expression to estimate its role in macrophage polarization, SOCS3/JAK2/STAT3 pathway activation, and motor behavior improvement. RESULTS: We found that EPC-EXOs decreased the macrophages' pro-inflammatory marker expression and increased their anti-inflammatory marker expression on the 7 and 14 days after SCI. The spinal cord H&E staining results showed that EPC-EXOs raised the tissue-sparing area rate significantly after 28 days of SCI and the motor behavior evaluation indicated an increased BMS score and motor-evoked potential by EPC-EXOs treatment after SCI. The RT-qPCR assay identified that miR-222-3P upregulated in EPC-EXOs and its miRNA-mimic also decreased the pro-inflammatory macrophages and increased the anti-inflammatory macrophages. Additionally, miR-222-3P mimic activated the SOCS3/JAK2/STAT3 pathway, and SOCS3/JAK2/STAT3 pathway inhibition blocked miR-2223P's effects on macrophage polarization and mouse motor behavior. CONCLUSION: Comprehensively, we discovered that EPC-EXOs-derived miR-222-3p affected macrophage polarization via SOCS3/JAK2/STAT3 pathway and promoted mouse functional repair after SCI, which reveals EPC-EXOs' role in modulation of macrophage phenotype and will provide a novel interventional strategy to induce post-SCI recovery.

Background: Interleukin-6 (IL-6) is produced by a variety of cells involved in inflammation and acts as local intensification signals in pathological processes associated with chronic eye inflammation. This meta-analysis was performed to provide a better understanding of the relationship between IL-6 and diabetic retinopathy.Methods: The study was started with systematic search for literatures by using the PubMed, Web of Science and Embase online databases. The standard mean difference (SMD) and its 95% confidence intervals (CIs) were was included and then pooled with a random effects model.Results: Thirty-one articles, containing1099 DR patients and 1010 controls, were included in this meta-analysis. The level of IL-6 in the DR group was found to be higher than that in the control group (SMD: 2.12, 95% CI: 1.53−2.70, p < 0.00001).Obvious heterogeneity existed between the studies (p < 0.00001, I2 = 96%). So a subgroup analysis and sensitivity analysis were performed. Removing the sensitivity studies, the stability of the overall treatment effect was good. Subgroup analysis showed that the levels of IL-6 in case group were observed to be higher than those in the control group; and the IL-6 levels in the proliferative diabetic retinopathy (PDR) group were also higher than those in the non-proliferative diabetic retinopathy (NPDR) group. (SMD: 0.78, 95% CI: 0.26–1.31, p= 0.003)Conclusion: The results from this current meta-analysis indicated that increased level of IL-6 generally exist in DR patients. And it may associated with the severity of DR. However, large-scale and high-quality studies in future are required to confirm the present findings.

Osteoclasts are the main cells involved in normal bone remodeling and pathological bone destruction in vivo. Overactivation of osteoclasts can lead to osteolytic diseases, including breast cancer, bone tumors, arthritis, the aseptic loosening of orthopedic implants, and Paget's disease. Excessive reactive oxygen species are the main cause of osteoclast overactivation. We have synthesized chitosan derived nitrogen-doped carbon dots (N-CDs) with a high synthetic yield and the ability to scavenge reactive oxygen species (ROS). N-CDs effectively abrogated RANKL-induced elevation in ROS generation and therefore impaired the activation of NF-κB and MAPK pathways. Osteoclastogenesis and bone resorption was effectively attenuated in vitro. Furthermore, the in vivo administration of N-CDs in mice protected them against lipopolysaccharide (LPS)-induced calvarial bone destruction and breast cancer cell-induced tibial bone loss. Based on the good biocompatibility of N-CDs and the ability to efficiently remove ROS, a nanomaterial treatment scheme was provided for the first time for the clinical treatment of osteolytic diseases.

aqueous solutions, respectively. Moreover, the effects of surface morphologies and Si substitution on cell attachment, proliferation, and osteogenic differentiation of rat bone marrow stromal cells (rBMSCs) were systematically investigated in vitro. The results showed that nano-topography surfaces could enhance cell attachment, cell proliferation, alkaline phosphatase (ALP) activity, and mRNA expression levels of collagen 1 (COL1), bone morphogenetic protein 2 (BMP-2), bone sialoprotein (BSP) and osteopontin (OPN). Moreover, the Si substitution could further promote cell proliferation and osteogenic differentiation, while Si-substituted bioceramics with a nanorod surface possessed the highest stimulatory effect. More importantly, the in vivo rat critical-sized calvarial defect model confirmed that HAp bioceramic scaffolds with nanosheet and nanorod surfaces showed definitive bone regeneration as compared with control HAp bioceramic scaffolds with a traditional smooth surface. Moreover, Si substitution could synergistically enhance bone regeneration and mineralization, while Si-substituted HAp bioceramic scaffolds with a nanorod surface achieved the best bone repair ability. The present study suggests that the modification of the surface morphology and Si substitution on the HAp bioceramic scaffold may be an effective synergistic strategy to improve its clinical performance.

Irisin is well-known to contribute to bone homeostasis due to its bidirectional regulation on osteogenesis and osteoclastogenesis. However, the mechanisms of irisin involved in mesenchymal stem/stromal cells (MSCs)-derived osteogenesis are still under investigated. Fibronectin type III domain-containing protein 5 (FNDC5) is the precursor protein of irisin, compare with wild type (WT) littermates, FNDC5 -/-mice lost bone mass significantly, collectively evidenced by the decrease of bone mineral density (BMD), impaired bone formation and reduced N-terminal propertied of type I procollagen (P1NP) in sera. Meanwhile, the bone resorbing of FNDC5 -/-mice has enhanced accompanied by increased tartrate phosphatase (TRAP) staining cells morphologically and cross-Linked C-telopeptide of type 1 collagen (CTX) level in sera. In vitro study showed that lack of irisin impeded the MSC-derived osteogenesis of FNDC5 -/-mice. The addition of irisin promote the osteogenesis of WT and irisin-deficient MSCs, by activating V integrin-induced ERK/STAT pathway, subsequently enhancing bone morphogenetic protein 2 (BMP2) expression and BMP/SMAD signaling activation. Taken together, these findings further indicate that irisin regulates bone homeostasis. Moreover, irisin promotes MSC-derived osteogenesis by binding to V integrin and activating BMP/SMAD signaling consequently. Thus, irisin may be a promising therapeutic target for osteoporosis and bone defects.

BACKGROUND: Hypoxia is the hallmark of the tumor microenvironment (TME) and plays a critical role during the progress of tumor development. A variety of microRNAs (miRNAs) transmitted by tumor-derived exosomes were involved in intercellular communication. We aimed to elucidate the precise mechanism by which tumor cell-derived exosomes promote lung cancer development by affecting macrophage polarization under hypoxic conditions. METHODS: CD163 signal in tumor tissue from lung cancer patients was detected by immunohistochemical (IHC). The M2 polarization-related markers were assessed by flow cytometry and western blot. Exosomes were isolated from normoxic and hypoxic lung cancer cell culture and characterized by transmission electron microscope (TEM), dynamic light scattering (DLS), and western blot. RNA sequencing was performed to show the abnormally expressed miRNAs in exosomes from normoxic and hypoxic lung cancer cell culture. In addition, CCK-8 and clone formation assays were used to assess cell proliferation. Dual luciferase reporter assay was used to evaluate the relationship between miR-21 and IRF1. For in vivo experiment, the male nude mice were injected with H1299 cells with exosomes and miR-21 mimic treatment. RESULTS: Firstly, we found a strong CD163 signal in tumor tissue from lung cancer patients by IHC. Subsequently, we co-cultured lung cancer cell line H1299 with M0 macrophage THP-1 and found that H1299 in a hypoxic environment promoted THP-1 M2 polarization. PKH67 fluorescence staining experiments confirmed that exosomes of H1299 origin were able to enter THP-1 and induced M2 polarization. RNA sequencing of exosomes showed that miR-21 level was significantly higher in the hypoxic culture group compared to the normoxic group. Subsequent cellular assays showed that miR-21 inhibited the expression of IRF1 by targeting it. In addition, the overexpression of IRF1 reversed the role of miR-21 on macrophage M2 polarization. Finally, we have confirmed through animal experiments that either hypoxic environment or high miR-21 level promoted tumor progression. CONCLUSIONS: High miR-21 level in hypoxic environments promoted macrophage M2 polarization and induced lung cancer progression through targeting IRF1.

Spherical TiO₂-NPs permeabilize the BBB most efficiently by inducing cytoskeletal re-organization, and the neurotoxicity of TiO₂-NPs appears minimal.