Automated fibroglandular tissue segmentation in breast MRI using generative adversarial networks.

Fibroglandular tissue (FGT) segmentation is a crucial step for quantitative analysis of background parenchymal enhancement (BPE) in magnetic resonance imaging (MRI), which is useful for breast cancer risk assessment. In this study, we develop an automated deep learning method based on a generative adversarial network (GAN) to identify the FGT region in MRI volumes and evaluate its impact on a specific clinical application. The GAN consists of an improved U-Net as a generator to generate FGT candidate areas and a patch deep convolutional neural network (DCNN) as a discriminator to evaluate the authenticity of the synthetic FGT region. The proposed method has two improvements compared to the classical U-Net: (1) the improved U-Net is designed to extract more features of the FGT region for a more accurate description of the FGT region; (2) a patch DCNN is designed for discriminating the authenticity of the FGT region generated by the improved U-Net, which makes the segmentation result more stable and accurate. A dataset of 100 three-dimensional (3D) bilateral breast MRI scans from 100 patients (aged 22-78 years) was used in this study with Institutional Review Board (IRB) approval. 3D hand-segmented FGT areas for all breasts were provided as a reference standard. Five-fold cross-validation was used in training and testing of the models. The Dice similarity coefficient (DSC) and Jaccard index (JI) values were evaluated to measure the segmentation accuracy. The previous method using classical U-Net was used as a baseline in this study. In the five partitions of the cross-validation set, the GAN achieved DSC and JI values of 87.0 ± 7.0% and 77.6 ± 10.1%, respectively, while the corresponding values obtained through by the baseline method were 81.1 ± 8.7% and 69.0 ± 11.3%, respectively. The proposed method is significantly superior to the previous method using U-Net. The FGT segmentation impacted the BPE quantification application in the following manner: the correlation coefficients between the quantified BPE value and BI-RADS BPE categories provided by the radiologist were 0.46 ± 0.15 (best: 0.63) based on GAN segmented FGT areas, while the corresponding correlation coefficients were 0.41 ± 0.16 (best: 0.60) based on baseline U-Net segmented FGT areas. BPE can be quantified better using the FGT areas segmented by the proposed GAN model than using the FGT areas segmented by the baseline U-Net.

Comparison of hemocoagulase atrox versus tranexamic acid used in primary total knee arthroplasty: A randomized controlled trial.

BACKGROUND: Total knee arthroplasty (TKA) has been considered as an effective choice for end-stage osteoarthritis or rheumatic arthritis. Tranexamic acid (TXA) has been widely used to prevent excessive blood loss perioperatively. Similarly, hemocoagulase atrox can significantly diminish blood loss and transfusion requirements in surgeries, however, it was rarely used in TKA. The purpose of this study is to identify whether hemocoagulase atrox is equal to TXA in reducing blood loss and transfusion rates following TKA, and compare clinical outcomes and complications between the two groups. METHODS: 74 patients were randomized to receive TXA (1.5 g intra-articular combined with 1.5 g intravenous), or hemocoagulase atrox (1 U intra-articular combined with 1 U intravenous). The primary outcome was total blood loss. The secondary outcomes included reduction of hemoglobin concentration, clinical outcomes, blood coagulation values, thromboembolic complications, and transfusion rates. RESULTS: The mean total blood loss was 431.7 mL in the TXA group compared with 644.6 mL in the hemocoagulase atrox group, with statistical significance (P < 0.05). There were significant differences in reduction of hemoglobin level (P < 0.05). The rate of deep vein thrombosis (DVT) in patients given TXA was higher than those given hemocoagulase atrox, however, there were no significant differences. No transfusions were required in either group, and no significant differences were found in the length of hospital stay and clinical outcomes. CONCLUSIONS: Although the blood loss was significantly greater in the hemocoagulase atrox group, no transfusions were required and no significant differences were observed for any other outcomes measured. Meanwhile, the rate of DVT in the hemocoagulase atrox group tends to be lower than those in TXA group. We concluded that hemocoagulase atrox was not superior to TXA in reducing perioperative blood loss. Further studies are warranted to evaluate if hemocoagulase atrox use could improve perioperative blood loss in patients with high thrombotic risk undergoing TKA.

Different roles of Akt and mechanistic target of rapamycin in serum­dependent chondroprotection of human osteoarthritic chondrocytes.

Despite various animal serums being used widely to culture chondrocytes, the regulatory mechanism of serum on chondrocyte activities has not been elucidated. In the present study, human osteoarthritis (OA) chondrocytes were used to perform in vitro investigations on the effect of different concentrations of bovine fetal serum on extracellular matrix synthesis, cell proliferation and autophagy using the Cell Counting Kit­8 analysis, a laser­scanning confocal microscope, and western blot analysis. The results demonstrated that 5% serum exerted a chondroprotective effect more than the other concentrations of serum, as it simultaneously promoted cell proliferation, autophagy, and ECM synthesis in human OA chondrocytes. Furthermore, the decreased mechanistic target of rapamycin (mTOR) and increased Akt were observed in 5% serum­treated OA chondrocytes. Either mTOR or Akt inhibitor influenced the effect of 5% serum on cell proliferation and autophagy in human OA chondrocytes, which was associated with LC­3B or B­cell lymphoma-2 (Bcl­2) signal molecules. Consistent with previous studies, the present study proposes that 5% serum promotes cell proliferation via the Akt/Bcl­2 axis and induces autophagy via the mTOR/LC­3B axis in human OA chondrocytes. Furthermore, the different roles of Akt and mTOR in the cell processes of human OA chondrocytes require consideration for preclinical and clinical therapy of OA.

Overexpression of microRNA-634 suppresses survival and matrix synthesis of human osteoarthritis chondrocytes by targeting PIK3R1.

Osteoarthritis (OA) is a degenerative disease characterized by deterioration of articular cartilage. Recent studies have demonstrated the importance of some microRNAs in cartilage damage. The aim of this study was to identify and characterize the expression of microRNA-634 (miR-634) in normal and OA chondrocytes, and to determine its role in OA pathogenesis. Human normal and OA chondrocytes obtained from patients were cultured in vitro. Transfection with miR-634 mimic or inhibitor was employed to investigate the effect of miR-634 on chondrocyte survival and matrix synthesis, and to identify miR-634 target. The results indicated that miR-634 was expressed at lower level in high grade OA chondrocyte compared with normal chondrocytes. Overexpression of miR-634 could inhibit cell survival and matrix synthesis in high grade OA chondrocytes. Furthermore, miR-634 targeted PIK3R1 gene that encodes the regulatory subunit 1 of class I PI3K (p85α) and exerted its inhibitory effect on the phosphorylation of Akt, mTOR, and S6 signal molecules in high grade OA chondrocytes. Therefore, the data suggested that miR-634 could suppress survival and matrix synthesis of high grade OA chondrocytes through targeting PIK3R1 gene to modulate the PI3K/Akt/S6 and PI3K/Akt/mTOR/S6 axes, with important implication for validating miR-634 as a potential target for OA therapy.

Protein kinase B and extracellular signal-regulated kinase contribute to the chondroprotective effect of morroniside on osteoarthritis chondrocytes.

Despite extensive studies on the multifaceted roles of morroniside, the main active constituent of iridoid glycoside from Corni Fructus, the effect of morroniside on osteoarthritis (OA) chondrocytes remains poorly understood. Here, we investigated the influence of morroniside on cultured human OA chondrocytes and a rat experimental model of OA. The results showed that morroniside enhanced the cell viability and the levels of proliferating cell nuclear antigen expression (PCNA), type II collagen and aggrecan in human OA chondrocytes, indicating that morroniside promoted chondrocyte survival and matrix synthesis. Furthermore, different doses of morroniside activated protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) in human OA chondrocytes, and in turn, triggered AKT/S6 and ERK/P70S6K/S6 pathway, respectively. The PI3K/AKT inhibitor LY294002 or the MEK/ERK inhibitor U0126 attenuated the effect of morroniside on human OA chondrocytes, indicating that the activation of AKT and ERK contributed to the regulation of morroniside in human OA chondrocytes. In addition, the intra-articular injection of morroniside elevated the level of proteoglycans in cartilage matrix and the thickness of articular cartilage in a rat experimental model of OA, with the increase of AKT and ERK activation. As a consequence, morroniside has chondroprotective effect on OA chondrocytes, and may have the therapeutic potential for OA treatment.

Berberine ameliorates cartilage degeneration in interleukin-1ß-stimulated rat chondrocytes and in a rat model of osteoarthritis via Akt signalling.

Berberine, a plant alkaloid used in Chinese medicine, has broad cell-protective functions in a variety of cell lines. Chondrocyte apoptosis contributes to the pathogenesis of cartilage degeneration in osteoarthritis (OA). However, little is known about the effect and underlying mechanism of berberine on OA chondrocytes. Here, we assessed the effects of berberine on cartilage degeneration in interleukin-1ß (IL-1ß)-stimulated rat chondrocytes and in a rat model of OA. The results of an MTT assay and western blotting analysis showed that berberine attenuated the inhibitory effect of IL-1ß on the cell viability and proliferating cell nuclear antigen expression in rat chondrocytes. Furthermore, berberine activated Akt, which triggered p70S6K/S6 pathway and up-regulated the levels of aggrecan and Col II expression in IL-1ß-stimulated rat chondrocytes. In addition, berberine increased the level of proteoglycans in cartilage matrix and the thickness of articular cartilage, with the elevated levels of Col II, p-Akt and p-S6 expression in a rat OA model, as demonstrated by histopathological and immunohistochemistry techniques. The data thus strongly suggest that berberine may ameliorate cartilage degeneration from OA by promoting cell survival and matrix production of chondrocytes, which was partly attributed to the activation of Akt in IL-1ß-stimulated articular chondrocytes and in a rat OA model. The resultant chondroprotective effects indicate that berberine merits consideration as a therapeutic agent in OA.

Requirement of the phosphatidylinositol 3-kinase/Akt signaling pathway for the effect of nicotine on interleukin-1beta-induced chondrocyte apoptosis in a rat model of osteoarthritis.

Chondrocyte apoptosis is mainly responsible for the progressive degeneration of cartilage in osteoarthritis (OA). Interleukin-1beta (IL-1ß) was widely used as a modulating and chondrocyte apoptosis-inducing agent. Nicotine is able to confer resistance to apoptosis and promote cell survival in some cell lines, but its regulatory mechanism is ambiguous. We aimed to investigate the effect of nicotine on IL-1ß-induced chondrocyte apoptosis and the mechanism underlying how nicotine antagonizes IL-1ß-induced apoptosis of rat chondrocytes. Chondrocytes isolated from newborn rat joints were exposed to IL-1ß. The cell viability was analyzed by the MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide) assay, and the apoptotic cells were counted with DAPI staining. The levels of Akt, phosphorylated-Akt (p-Akt) and downstream protein targets of Akt were detected by western blotting. The results showed that nicotine neutralized the effect of IL-1ß on chondrocytes by activating PI3K/Akt signaling pathways, including the PI3K/Akt/Bcl-2 pathway, to block IL-1ß-induced cell apoptosis and the PI3K/Akt/p70S6K (p70S6 kinase)/S6 pathway for promoting protein synthesis, modulating its downstream effectors such as TIMP-1 and MMP-13. Activation of the PI3K/Akt pathway is, in part, required for the effect of nicotine on IL-1ß-induced chondrocyte apoptosis in a rat model of osteoarthritis.

[Effects of PTHrP and Notch signaling on the proliferation of epiphysis stem cells].

OBJECTIVE: To study the regulation of the proliferation of epiphysis stem cells by the PTHrP (parathyroid hormone related peptide) and Notch signaling systems. METHODS: An organ culture system of femurs of SD rat in 24 h after birth was employed. PTHrP (1 - 34) was used as the activator of the PTHrP signaling pathway and PTHrP (7 - 34) as the antagonist of PTH (parathyroid hormone)-receptor. For Notch signaling system, Jagged1/Fc was used as the activator and DAPT as its inhibitor. The femurs were cultured in DMEM (Dulbecco's modified Eagle's medium)/F12 medium while phosphate buffered saline was used for the control groups. Hematoxylin and eosin staining and bromodeoxyuridine analysis were used to analyze the length of the epiphysis stem cells zone and the proliferation of epiphysis stem cells. The expression of NICD (Notch intra-cellular domain) and Jagged1 were analyzed by immunohistochemistry. The epiphysis stem cells were transfected with the lentiviral vectors with rat PTHrP gene overexpression or inhibition properties, the cells transfected with the PGC-GFP-lentivirus or NC-GFP-lentivirus were used as control. Western blot was employed to detect the expression of NICD and Jagged1 genes. RESULTS: PTHrP (1 - 34) and Jagged1/Fc could dramatically elevate the rate of epiphysis stem cells zone by the whole growth plate length measurement while PTHrP (7 - 34) and DAPT could decrease the rate. Brdu analysis also showed that the number of proliferative epiphysis stem cells could be up-regulated by the PTHrP (1 - 34) or Jagged1/Fc signaling. By contrast, the treatment with PTHrP (7 - 34) or DAPT reduced the number of proliferative epiphysis stem cells. Immunohistochemistry and Western blot showed a significantly elevated expression of NICD and Jagged1 when PTHrP signaling was activated while a reductive expression of NICD and Jagged1 when PTHrP signaling was inactivated. CONCLUSION: Both of PTHrP and Notch signaling system could promote the proliferation of epiphysis stem cells. And the PTHrP signaling can stimulate Notch signaling to promote the proliferation of epiphysis stem cells.