Mesenchymal stem cell-conditioned medium improved mitochondrial function and alleviated inflammation and apoptosis in non-alcoholic fatty liver disease by regulating SIRT1

Non-alcoholic fatty liver disease (NAFLD), an emerging risk factor for diabetes, is now recognized as the most common liver disease worldwide. Mesenchymal stem cells (MSCs), a promising tool in regenerative medicine, release abundant molecules into the conditioned medium (CM). Increasing evidence showed that MSC-CM is beneficial for diabetes-associated NAFLD. However, the mechanism of how MSC-CM improves NAFLD remains uncertain. In this study, to determine the effects of MSC-CM on NAFLD, streptozotocin (STZ) and high-fat diet (HFD) induced T2DM mice model and palmitic acid (PA)-stimulated L-O2 cells were used and treated with MSC-CM. Our results demonstrated that MSC-CM improved insulin resistance in diabetic mice, amended the pathological structure of the liver, enhanced the liver's total antioxidant capacity and mitochondrial function, reduced inflammation and cell apoptosis. We further verified that SIRT1 played a key role in mediating the protective effect of MSC-CM. These findings provide novel evidence that MSC-CM has the potential to treat T2DM patients with NAFLD clinically.

Bioactivity Prediction Based on Matched Molecular Pair and Matched Molecular Series Methods

BACKGROUND

Enhancing a compound's biological activity is the central task for lead optimization in small molecules drug discovery. However, it is laborious to perform many iterative rounds of compound synthesis and bioactivity tests. To address the issue, it is highly demanding to develop high quality in silico bioactivity prediction approaches, to prioritize such more active compound derivatives and reduce the trial-and-error process.

METHODS

Two kinds of bioactivity prediction models based on a large-scale structure-activity relationship (SAR) database were constructed. The first one is based on the similarity of substituents and realized by matched molecular pair analysis, including SA, SA_BR, SR, and SR_BR. The second one is based on SAR transferability and realized by matched molecular series analysis, including Single MMS pair, Full MMS series, and Multi single MMS pairs. Moreover, we also defined the application domain of models by using the distance-based threshold.

RESULTS

Among seven individual models, Multi single MMS pairs bioactivity prediction model showed the best performance (R2 = 0.828, MAE = 0.406, RMSE = 0.591), and the baseline model (SA) produced the most lower prediction accuracy (R2 = 0.798, MAE = 0.446, RMSE = 0.637). The predictive accuracy could further be improved by consensus modeling (R2 = 0.842, MAE = 0.397 and RMSE = 0.563).

CONCLUSION

An accurate prediction model for bioactivity was built with a consensus method, which was superior to all individual models. Our model should be a valuable tool for lead optimization.

One step further into the blackbox: a pilot study of how to build more confidence around an AI-based decision system of breast nodule assessment in 2D ultrasound

OBJECTIVES

To investigate how a DL model makes decisions in lesion classification with a newly defined region of evidence (ROE) by incorporating "explainable AI" (xAI) techniques.

METHODS

A data set of 785 2D breast ultrasound images acquired from 367 females. The DenseNet-121 was used to classify whether the lesion is benign or malignant. For performance assessment, classification results are evaluated by calculating accuracy, sensitivity, specificity, and receiver operating characteristic for experiments of both coarse and fine regions of interest (ROIs). The area under the curve (AUC) was evaluated, and the true-positive, false-positive, true-negative, and false-negative results with breakdown in high, medium, and low resemblance on test sets were also reported.

RESULTS

The two models with coarse and fine ROIs of ultrasound images as input achieve an AUC of 0.899 and 0.869, respectively. The accuracy, sensitivity, and specificity of the model with coarse ROIs are 88.4%, 87.9%, and 89.2%, and with fine ROIs are 86.1%, 87.9%, and 83.8%, respectively. The DL model captures ROE with high resemblance of physicians' consideration as they assess the image.

CONCLUSIONS

We have demonstrated the effectiveness of using DenseNet to classify breast lesions with limited quantity of 2D grayscale ultrasound image data. We have also proposed a new ROE-based metric system that can help physicians and patients better understand how AI makes decisions in reading images, which can potentially be integrated as a part of evidence in early screening or triaging of patients undergoing breast ultrasound examinations.

KEY POINTS

• The two models with coarse and fine ROIs of ultrasound images as input achieve an AUC of 0.899 and 0.869, respectively. The accuracy, sensitivity, and specificity of the model with coarse ROIs are 88.4%, 87.9%, and 89.2%, and with fine ROIs are 86.1%, 87.9%, and 83.8%, respectively. • The first model with coarse ROIs is slightly better than the second model with fine ROIs according to these evaluation metrics. • The results from coarse ROI and fine ROI are consistent and the peripheral tissue is also an impact factor in breast lesion classification.

A Lattice-Based Homomorphic Proxy Re-Encryption Scheme with Strong Anti-Collusion for Cloud Computing

The homomorphic proxy re-encryption scheme combines the characteristics of a homomorphic encryption scheme and proxy re-encryption scheme. The proxy can not only convert a ciphertext of the delegator into a ciphertext of the delegatee, but also can homomorphically calculate the original ciphertext and re-encryption ciphertext belonging to the same user, so it is especially suitable for cloud computing. Yin et al. put forward the concept of a strong collusion attack on a proxy re-encryption scheme, and carried out a strong collusion attack on the scheme through an example. The existing homomorphic proxy re-encryption schemes use key switching algorithms to generate re-encryption keys, so it can not resist strong collusion attack. In this paper, we construct the first lattice-based homomorphic proxy re-encryption scheme with strong anti-collusion (HPRE-SAC). Firstly, algorithm TrapGen is used to generate an encryption key and trapdoor, then trapdoor sampling is used to generate a decryption key and re-encryption key, respectively. Finally, in order to ensure the homomorphism of ciphertext, a key switching algorithm is only used to generate the evaluation key. Compared with the existing homomorphic proxy re-encryption schemes, our HPRE-SAC scheme not only can resist strong collusion attacks, but also has smaller parameters.

Visualization of an Accelerated Electrochemical Reaction under an Enhanced Electric Field

Locally enhanced electric fields produced by high-curvature structures have been reported to boost the charge transport process and improve the relevant catalytic activity. However, no visual evidence has been achieved to support this new electrochemical mechanism. Here, accelerated electrochemiluminescence (ECL) reactions emitting light are visualized for the first time at the heterogeneous interfaces between microbowls and the supporting electrode surface. The simulation result shows that the electric intensity at the interface with a high curvature is 40-fold higher than that at the planar surface. Consequently, local high electric fields concentrate reactive species to the heterogeneous interfaces and efficiently promote the charge transport reactions, which directly leads to the enhancement of ECL emission surrounding the microbowls. Additionally, the potential to induce visual ECL from a ruthenium complex drops to 0.9 V, which further illustrates the promotion of an electrochemical reaction with the aid of an enhanced electric field. This important visualization of electric field boosted electrochemical reactions helps to establish the proposed electron transfer mechanism and provide an alternative strategy to improve electrocatalytic efficiency.

Cross-Sectional Analysis of the Involvement of Interleukin-17A in Diabetic Retinopathy in Elderly Individuals with Type 2 Diabetes Mellitus

BACKGROUND

To investigate the correlation between serum interleukin-17A (IL-17A) levels and diabetic retinopathy (DR) in elderly individuals with type 2 diabetes mellitus (T2DM).

METHODS

The study included 194 elderly patients (94 males and 100 females) with T2DM. Digital retinal photography as well as fundus fluorescein angiography was employed to distinguish between nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). In addition, multiple logistic regression analysis was conducted to determine the correlation between serum IL-17A levels and DR status.

RESULTS

The average age of the study cohort was 69.14 ± 6.33 years, of which 52.08% were male. The study participants with the highest IL-17A (Q4) levels had higher TC, DBP, and low-density lipoprotein cholesterol (LDL-C) values than those the other groups. Analysis using unadjusted and adjusted linear regression revealed that the effect size of 1.09 for DR in the unadjusted model indicates that IL-17A is associated with an increase of 1.09 in DR (mmol/L) (β 1.09, 95% confidence interval (CI) 1.03, 1.16). Using the minimum-adjusted model (the model 2), as IL-17A increased, DR was higher by 1.11 (β 1.11, 95% CI 1.04, 1.18). With the fully adjusted model (the model 3), for each additional IL-17A increase, DR was higher by 1.15 (β 1.15, 95% CI 1.06, 1.24).

CONCLUSION

Serum IL-17A levels are apparently positively correlated to DR in Chinese elderly individuals with T2DM.

Correction: Regioselective synthesis of substituted thiazoles via cascade reactions from 3-chlorochromones and thioamides

Correction for 'Regioselective synthesis of substituted thiazoles via cascade reactions from 3-chlorochromones and thioamides' by Tianzi Dai et al., Org. Biomol. Chem., 2020, 18, 6162-6170, DOI: .

Tannic Acid-Silver Dual Catalysis Induced Rapid Polymerization of Conductive Hydrogel Sensors with Excellent Stretchability, Self-Adhesion, and Strain-Sensitivity Properties

The application of conductive hydrogels in intelligent biomimetic electronics is a hot topic in recent years, but it is still a great challenge to develop the conductive hydrogels through a rapid fabrication process at ambient temperature. In this work, a versatile poly(acrylamide) @cellulose nanocrystal/tannic acid-silver nanocomposite (NC) hydrogel integrated with excellent stretchability, repeatable self-adhesion, high strain sensitivity, and antibacterial property, was synthesized via radical polymerization within 30 s at ambient temperature. Notably, this rapid polymerization was realized through a tannic acid-silver (TA-Ag) mediated dynamic catalysis system that was capable of activating ammonium persulfate and then initiated the free-radical polymerization of the acrylamide monomer. Benefiting from the incorporation of TA-Ag metal ion nanocomplexes and cellulose nanocrystals, which acted as dynamic connecting bridges by hydrogen bonds to efficiently dissipate energy, the obtained NC hydrogels exhibited prominent tensile strain (up to 4000%), flexibility, self-recovery, and antifatigue properties. In addition, the hydrogels showed repeatable adhesiveness to different substrates (e.g., glass, wood, bone, metal, and skin) and significant antibacterial properties, which were merits for the hydrogels to be assembled into a flexible epidermal sensor for long-term human-machine interfacial contact without concerns about the use of external adhesive tapes and bacterial breeding. Moreover, the remarkable conductivity (σ ∼ 5.6 ms cm^-1) and strain sensitivity (gauge factor = 1.02) allowed the flexible epidermal sensors to monitor various human motions in real time, including huge movement of deformations (e.g., wrist, elbow, neck, shoulder) and subtle motions. It is envisioned that this work would provide a promising strategy for the rapid preparation of conductive hydrogels in the application of flexible electronic skin, biomedical devices, and soft robotics.

The STING-IRF3 pathway is involved in lipotoxic injury of pancreatic β cells in type 2 diabetes

Lipotoxic injury of pancreatic β cells is an important pathological feature in type 2 diabetes mellitus (T2DM). Stimulator of interferon genes (STING) can recognize its own DNA leaked into the cytoplasm from damaged mitochondria or nuclei of the host cell, thus activating its downstream factor interferon regulatory factor 3 (IRF3), causing inflammation and apoptosis. The STING-IRF3 signaling pathway is closely related to glycolipid metabolism, but its relationship with the lipotoxicity of pancreatic β cells has rarely been reported. Here, we investigated the role of the STING-IRF3 signaling pathway in lipotoxicity-induced inflammation, apoptosis, and dysfunction of pancreatic β cells. We examined the activation of STING and IRF3 in islets of db/db mice and identified the role of the STING-IRF3 signaling pathway in palmitic acid (PA)-induced lipotoxic injury of INS-1, a rat insulinoma cell line. STING and phosphorylated IRF3 including downstream interferon-β were upregulated in islets of db/db mice and PA-induced INS-1 cells. Gene silencing of STING or IRF3 ameliorated PA-induced INS-1 cell inflammation and apoptosis, and reversed impaired insulin synthesis. Additionally, PA induced downregulation of the phosphoinositide 3-kinase-AKT signaling pathway, and impaired high glucose-stimulated insulin secretion was reversed after knockdown of STING or IRF3. Our results suggest that activation of the STING-IRF3 pathway triggers inflammation and apoptosis of pancreatic β cells, leading to β-cell damage and dysfunction. Hence, inhibition of this signaling pathway may represent a novel approach for β-cell protection in T2DM.

Detection of Myocardial Fibrosis and Left Ventricular Dysfunction with Cardiac MRI in a Hypertensive Swine Model

Purpose

To quantitatively evaluate the dynamic changes of extracellular volume (ECV) and native T1 in hypertensive swine over time using histologic findings as standard of reference.

Materials and Methods

Eighteen hypertensive (hypertension group) and six healthy (control group) swine aged 6-12 months were studied. Both groups underwent cardiac MRI, including pre- and postcontrast T1 mapping and late gadolinium enhancement (LGE) imaging at three time points: baseline, 1 month, and 3 months after hypertensive model induction. The left ventricular function, strain, and strain rate were also calculated using the cine images. Animals were killed after the last MRI examination. Histopathologic examination of the heart was performed later. Analysis of the relationship between strain, ECV, and native T1 was carried out by Pearson correlation and linear regression models.

Results

The mean systolic and diastolic pressure increased from 111 mg Hg and 68 mm Hg to 160 mm Hg and 97 mm Hg, respectively, over 3 months during developing hypertension (P = .03, .02, respectively). There was no LGE detected at any of three imaging times. The ECV and native T1 value of myocardium in the hypertension group increased over 3 months (ECV, increased from 21.5% ± 4.4 to 27.3% ± 5.4; native T1, increased from a mean of 1056 msec ± 32 [standard deviation] to 1218 msec ± 66; all P < .001). The collagen volume fraction (CVF) was calculated and correlated with ECV (r = 0.63, P = .01) and native T1 (r = 0.80, P < .001). In addition, ECV was associated with longitudinal diastolic strain rate (r =-.34, P = .04). Native T1 was associated with radial strain (r = -0.62, P < .001) as well as circumferential strain (r = 0.57, P < .001).

Conclusion

Native T1 and ECV correlated significantly with the CVF, indicating that early myocardial interstitial fibrosis exists in hypertensive heart disease. As hypertension progresses, the values of ECV fraction and T1 native increase. Supplemental material is available for this article. © RSNA, 2020.

Effect of 0.01% atropine eye drops on choroidal thickness in myopic children

PURPOSE

To examine the effects of low-dose atropine on the choroidal thickness (CT) of young children in Shanghai, China, as well as the ocular biometrics of myopic patients.

METHODS

A total of 59 eyes of 35 myopic children had subfoveal CT and ocular biometry measurements taken before and after 2weeks, 4weeks, and 8weeks of treatment with 0.01% atropine. All eyes were measured using swept-source optical coherence tomography. CT and changes in it were also recorded.

RESULTS

The choroid exhibited significant and continuous thickening under the fovea after patients were treated with 0.01% atropine. The magnitude of change in CT varied with the location and with the duration of treatment. The greatest change was observed in the fovea. There was no significant relationship between changes in subfoveal CT and axial length.

CONCLUSIONS

Using 0.01% atropine eye drops significantly increased CT in eyes of young myopic children, by variable magnitude depending upon location.

Glucagon-Like Peptide 1 Attenuates Lipotoxicity-Induced Islet Dysfunction in ApoE-/- Mice

AIM

Glucagon-like peptide-1 (GLP1) is known to decrease glucagon release and may be beneficial for the reduction of elevated blood glucose. However, its role and mechanism of action in diabetes remain elusive. This study aimed to examine the function of GLP1 and analyze the mechanism of effect that GLP1exerts on inducible nitric oxide synthase (iNOS) in diabetic mice.

METHODS

A diabetes model was established in ApoE-/- mice fed a high-fat diet and treated with GLP1 and/or lentivirus-expressing PARP1. PARP1, iNOS, and inflammatory factors in islets were detected by Western blot and ELISA. Islet α cells and β cells and CD8+ T lymphocytes were detected by immunostaining. Islet-cell apoptosis was detected by TUNEL.

RESULTS

GLP1 inhibited the expression of PARP1 and iNOS in islets, alleviated decrease in β cells, and suppressed cell apoptosis induced by the high-fat diet. Moreover, GLP1 recovered the decline in insulin sensitivity and glucose tolerance in ApoE-/- mice fed the high-fat diet, and the effects of GLP1 were related to the inhibition of COX2 and NFκB expression.

CONCLUSION

GLP1 significantly alleviated the decrease in β-cell numbers, suppressed β-cell apoptosis induced by the high-fat diet, inhibited the expression of iNOS, and alleviated inflammatory islet injury via inhibiting the COX2-NFκB pathway.

Anti-CD19 mAb-conjugated human serum albumin nanoparticles effectively deliver doxorubicin to B-lymphoblastic leukemia cells

B-Lymphoblastic leukemia (B-LL) is the most common childhood hematological malignancy. Although its overall prognosis is good, the outcome after relapse is poor. CD19 is highly expressed on the membrane of most malignant B-cells, and was shown to be a promising therapeutic target of B-LL. In this present work, we designed and synthesized a novel drug carrier, anti-CD19 monoclonal antibody-conjugated human serum albumin nanoparticles (HSA-CD19 NPs). Doxorubicin (DOX) was well encapsulated into the HSA-CD19 NPs to form an anticancer nanodrug DOX/HSA-CD19. DOX/HSA-CD19 was preferentially uptaken by CD19⁺ B-LL cell line KOPN-8. DOX/HSA-CD19 showed strong antiproliferative effect on KOPN-8 cells with an IC₅₀ value of 4.1 μg/mL. Further, proapoptotic Bax and caspase-3 were significantly elevated, but antiapoptotic Bcl2 was reduced in DOX/HSA-CD19 treated KOPN-8 cells, indicating the activation of the apoptosis pathway by the nanodrug. By contrast, DOX/HSA-CD19 did not show affinity to CD19-monocytic cell line, U937, and did not affect its proliferation. Collectively, HSA-CD19 NPs are a kind of effective novel drug carrier, and DOX/HSA-CD19 is a promising antitumor nanodrug for the treatment of B-LL.

Role of PTH1R Signaling in Prx1+ Mesenchymal Progenitors during Eruption

Tooth eruption is a complex process requiring precise interaction between teeth and adjacent tissues. Molecular analysis demonstrates that bone remodeling plays an essential role during eruption, suggesting that a parathyroid hormone 1 receptor (PTH1R) gene mutation is associated with disturbances in bone remodeling and results in primary failure of eruption (PFE). Recent research reveals the function of PTH1R signaling in mesenchymal progenitors, whereas the function of PTH1R in mesenchymal stem cells during tooth eruption remains incompletely understood. We investigated the specific role of PTH1R in Prx1⁺ progenitor expression during eruption. We found that Prx1⁺-progenitors occur in mesenchymal stem cells residing in alveolar bone marrow surrounding incisors, at the base of molars and in the dental follicle and pulp of incisors. Mice with conditional deletion of PTH1R using the Prx1 promoter exhibited arrested mandibular incisor eruption and delayed molar eruption. Micro-computed tomography, histomorphometry, and molecular analyses revealed that mutant mice had significantly reduced alveolar bone formation concomitant with downregulated gene expression of key regulators of osteogenesis in PTH1R-deficient cells. Moreover, culturing orofacial bone-marrow-derived mesenchymal stem cells (OMSCs) from Prx1Cre;PTH1R^fl/fl mice or from transfecting Cre recombinase adenovirus in OMSCs from PTH1R^fl/fl mice suggested that lack of Pth1r expression inhibited osteogenic differentiation in vitro. However, bone resorption was not affected by PTH1R ablation, indicating the observed reduced alveolar bone volume was mainly due to impaired bone formation. Furthermore, we found irregular periodontal ligaments and reduced Periostin expression in mutant incisors, implying loss of PTH1R results in aberrant differentiation of periodontal ligament cells. Collectively, these data suggest that PTH1R signaling in Prx1⁺ progenitors plays a critical role in alveolar bone formation and periodontal ligament development during eruption. These findings have implications for our understanding of the physiologic and pathologic function of PTH1R signaling in tooth eruption and the progression of PFE.

Mesenchymal stem cell-derived exosomes exert ameliorative effects in type 2 diabetes by improving hepatic glucose and lipid metabolism via enhancing autophagy

Background

Mesenchymal stem cell (MSC)-based therapy is currently considered to be an effective treatment strategy for diabetes and hepatic disorders, such as liver cirrhosis and non-alcoholic fatty liver disease. Exosomes are important mediators of cellular connections, and increasing evidence has suggested that exosomes derived from MSCs may be used as direct therapeutic agents; their mechanisms of action, however, remain largely unclear. Here, we evaluated the efficacy and molecular mechanisms of human umbilical cord MSC-derived exosomes (HucMDEs) on hepatic glucose and lipid metabolism in type 2 diabetes mellitus (T2DM).

Methods

HucMDEs were used to treat T2DM rats, as well as palmitic acid (PA)-treated L-O2 cells, in order to determine the effects of HucMDEs on hepatic glucose and lipid metabolism. To evaluate the changes in autophagy and potential signaling pathways, autophagy-related proteins (BECN1, microtubule-associated protein 1 light chain 3 beta [MAP 1LC3B]), autophagy-related genes (ATGs, ATG5, and ATG7), AMP-activated protein kinase (AMPK), and phosphorylated AMPK (p-AMPK) were assessed by Western blotting.

Results

HucMDEs promoted hepatic glycolysis, glycogen storage, and lipolysis, and reduced gluconeogenesis. Additionally, autophagy potentially contributed to the effects of HucMDE treatment. Transmission electron microscopy revealed an increased formation of autophagosomes in HucMDE-treated groups, and the autophagy marker proteins, BECN1 and MAP 1LC3B, were also increased. Moreover, autophagy inhibitor 3-methyladenine significantly reduced the effects of HucMDEs on glucose and lipid metabolism in T2DM rats. Based on its phosphorylation status, we found that the AMPK signaling pathway was activated and induced autophagy in T2DM rats and PA-treated L-O2 cells. Meanwhile, the transfection of AMPK siRNA or application of the AMPK inhibitor, Comp C, weakened the therapeutic effects of HucMDEs on glucose and lipid metabolism.

Conclusions

These findings demonstrate that HucMDEs improved hepatic glucose and lipid metabolism in T2DM rats by activating autophagy via the AMPK pathway, which provides novel evidence suggesting the potential for HucMDEs in clinically treating T2DM patients.

Antibacterial Activity of Fruiting Body Extracts from Culinary-Medicinal Winter Mushroom, Flammulina velutipes (Agaricomycetes) against Oral Pathogen Streptococcus mutans

The edible medicinal mushroom Flammulina velutipes (enokitake) has many applications as food and medicine, but its application in dentistry is unknown. This study aims to investigate the inhibitory effect of fruiting body extracts from F. velutipes on the growth and adhesion of Streptococcus mutans, the main cause of human caries, in vitro. Of the four extracts (named TG01 from water, TG02 from 95% ethanol, TG03 from 50% ethanol, and TG04 from ethyl acetate), TG03 had significant antibacterial activity (MIC = 10 mg/mL; MBC = 20 mg/mL). Planktonic growth and biofilm formation in S. mutans was repressed by TG03 at 5 mg/mL and above. Meanwhile, cytotoxicity analysis showed that TG03 was not toxic to human oral keratinocyte cells. HPLC-QQQ-MS analysis showed that the TG03 extract contained a large amount of arabitol, a sucrose substitute that reduces the development of caries. Thus, F. velutipes extracts can effectively inhibit the growth of the oral pathogen S. mutans without cytotoxicity against human oral keratinocytes. Therefore, F. velutipes is a good candidate for the development of oral hygiene agents to control dental caries.

Preventing Child Sexual Abuse Using Picture Books: The Effect of Book Character and Message Framing

The aim of this study was to investigate whether and how a picture book preventing child sexual abuse can improve children's self-protection skills. The study was conducted in China with Chinese children. In a 2 × 2 between-subjects design, character in the book (human versus animal) and message framing (gain versus loss) were manipulated. Compared to a baseline group who were not exposed to the prevention book, children in the experimental groups significantly enhanced their ability to recognize a potential abuse situation and refuse an inappropriate touch request. Results suggest that the prevention picture books are more effective when using a human character and a gain-framed message. The explanation for this was that human characters simulated children's perceived norm and gain-framed messages increased children's message recall, perceived self-efficacy and positive attitude toward the message, all of which in turn positively affected children's self-protection skills.

Parathyroid hormone ameliorates temporomandibular joint osteoarthritic-like changes related to age

OBJECTIVES

Ageing could be a contributing factor to the progression of temporomandibular joint osteoarthritis (TMJ OA), whereas its pathogenesis and potential therapeutic strategy have not been comprehensively investigated.

MATERIALS AND METHODS

We generated ageing mouse models (45-week and 60-week; 12-week mice as control) and intermittently injected 45-week mice with parathyroid hormone (PTH(1-34)) or vehicle for 4 weeks. Cartilage and subchondral bone of TMJ were analysed by microCT, histological and immunostaining. Western blot, qRT-PCR, ChIP, ELISA and immunohistochemical analysis were utilized to examination the mechanism of PTH(1-34)'s function.

RESULTS

We showed apparent OA-like phenotypes in ageing mice. PTH treatment could ameliorate the degenerative changes and improve bone microarchitecture in the subchondral bone by activating bone remodelling. Moreover, PTH inhibited phosphorylation level of Smad3, which can combine with p16^ink4a gene promoter region, resulting in reduced senescent cells accumulation and increased cellular proliferation of marrow mesenchymal stem cells (MSCs). ELISA also showed relieved levels of specific senescent-associated secretory phenotype (SASP) in ageing mice after PTH treatment.

CONCLUSIONS

In summary, PTH may reduce the accumulation of senescent cells in subchondral bone by inhibiting p16^ink4a and improve bone marrow microenvironment to active bone remodelling process, indicating PTH administration could be a potential preventative and therapeutic treatment for age-related TMJ OA.

Integrin β1D Deficiency-Mediated RyR2 Dysfunction Contributes to Catecholamine-Sensitive Ventricular Tachycardia in Arrhythmogenic Right Ventricular Cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary heart disease characterized by fatty infiltration, life-threatening arrhythmias, and increased risk of sudden cardiac death. The guideline for management of ARVC in patients is to improve quality of life by reducing arrhythmic symptoms and to prevent sudden cardiac death. However, the mechanism underlying ARVC-associated cardiac arrhythmias remains poorly understood.

METHODS

Using protein mass spectrometry analyses, we identified that integrin β1 is downregulated in ARVC hearts without changes to Ca²⁺-handling proteins. As adult cardiomyocytes express only the β1D isoform, we generated a cardiac specific β1D knockout mouse model and performed functional imaging and biochemical analyses to determine the consequences of integrin β1D loss on function in the heart in vivo and in vitro.

RESULTS

Integrin β1D deficiency and RyR2 Ser-2030 hyperphosphorylation were detected by Western blotting in left ventricular tissues from patients with ARVC but not in patients with ischemic or hypertrophic cardiomyopathy. Using lipid bilayer patch clamp single channel recordings, we found that purified integrin β1D protein could stabilize RyR2 function by decreasing RyR2 open probability, mean open time, and increasing mean close time. Also, β1D knockout mice exhibited normal cardiac function and morphology but presented with catecholamine-sensitive polymorphic ventricular tachycardia, consistent with increased RyR2 Ser-2030 phosphorylation and aberrant Ca²⁺ handling in β1D knockout cardiomyocytes. Mechanistically, we revealed that loss of DSP (desmoplakin) induces integrin β1D deficiency in ARVC mediated through an ERK1/2 (extracellular signal-regulated kinase 1 and 2)-fibronectin-ubiquitin/lysosome pathway.

CONCLUSIONS

Our data suggest that integrin β1D deficiency represents a novel mechanism underlying the increased risk of ventricular arrhythmias in patients with ARVC.

Aortic regurgitation is common in hypertrophic cardiomyopathy: An echocardiography and cardiovascular magnetic resonance study

PURPOSE

To investigate the incidence, mechanism, and risk factors of aortic regurgitation (AR) in patients with hypertrophic cardiomyopathy (HCM) by using echocardiography and cardiac magnetic resonance (CMR).

METHODS

105 HCM patients, 52 hypertension (HTN) patients and 50 healthy controls (HC) were retrospectively recruited. HCM patients were divided into 38 with AR (HCMAR) subject and 67 without AR. The subaortic complex, D1 (the largest distance of the interventricular septum that protruded into the LVOT) and D3 (the LVOT effective width) were assessed and compared between the two groups of HCM patients.

RESULTS

AR was more common in HCM than in HTN and HC (36 %, 17 %, and 10 %, respectively, P = 0.001). HCM patients with AR were older (58 ± 11 vs. 45 ± 16 years, P < 0.001) and had a higher incidence of hypertension (55 % vs. 33 %, P = 0.03). D1 was greater (13.5 ± 4.4 vs. 10.6 ± 4.0 mm, P = 0.001), and D3 was shorter in the HCMAR group (10.2 ± 5.3 vs. 13.7 ± 5.9 mm, P = 0.003). Anterior mitral leaflet length and left atrial diameter were greater in HCMAR group (all P < 0.05). On multivariable logistic regression analysis, the independent risk factors of AR in HCM patients were LVOTO and age.

CONCLUSIONS

This study demonstrated that AR is a common comorbidity of HCM, especially in patients with LVOTO. LVOTO and age were independent risk factors of AR in HCM patient.