IntroductionObesity is a major risk factor for the development of osteoarthritis in both weight-bearing and nonweight-bearing joints. The mechanisms by which obesity influences the structural or symptomatic features of osteoarthritis are not well understood, but may include systemic inflammation associated with increased adiposity. In this study, we examined biomechanical, neurobehavioral, inflammatory, and osteoarthritic changes in C57BL/6J mice fed a high-fat diet.MethodsFemale C57BL/6J mice were fed either a 10% kcal fat or a 45% kcal fat diet from 9 to 54 weeks of age. Longitudinal changes in musculoskeletal function and inflammation were compared with endpoint neurobehavioral and osteoarthritic disease states. Bivariate and multivariate analyses were conducted to determine independent associations with diet, percentage body fat, and knee osteoarthritis severity. We also examined healthy porcine cartilage explants treated with physiologic doses of leptin, alone or in combination with IL-1α and palmitic and oleic fatty acids, to determine the effects of leptin on cartilage extracellular matrix homeostasis.ResultsHigh susceptibility to dietary obesity was associated with increased osteoarthritic changes in the knee and impaired musculoskeletal force generation and motor function compared with controls. A high-fat diet also induced symptomatic characteristics of osteoarthritis, including hyperalgesia and anxiety-like behaviors. Controlling for the effects of diet and percentage body fat with a multivariate model revealed a significant association between knee osteoarthritis severity and serum levels of leptin, adiponectin, and IL-1α. Physiologic doses of leptin, in the presence or absence of IL-1α and fatty acids, did not substantially alter extracellular matrix homeostasis in healthy cartilage explants.ConclusionsThese results indicate that diet-induced obesity increases the risk of symptomatic features of osteoarthritis through changes in musculoskeletal function and pain-related behaviors. Furthermore, the independent association of systemic adipokine levels with knee osteoarthritis severity supports a role for adipose-associated inflammation in the molecular pathogenesis of obesity-induced osteoarthritis. Physiologic levels of leptin do not alter extracellular matrix homeostasis in healthy cartilage, suggesting that leptin may be a secondary mediator of osteoarthritis pathogenesis.

Objective. To examine the pathogenetic mechanisms of osteoarthritis (OA)-like changes in Col9a1 ؊/؊ mice, which are deficient in type IX collagen.Methods. Knee joints and temporomandibular joints (TMJs) from Col9a1 ؊/؊ mice and their wild-type (Col9a1 ؉/؉ ) littermates were examined by light microscopy. Immunohistochemical staining was performed to examine the expression of matrix metalloproteinase 3 (MMP-3) and MMP-13, degraded type II collagen, and the discoidin domain receptor 2 (DDR-2) in knee joints. Cartilage mechanics were also evaluated for compressive properties by microindentation testing of the tibial plateau and for tensile properties by osmotic loading of the femoral condyle.Results. Histologic analysis showed agedependent OA-like changes in the knee and TMJs of Col9a1 ؊/؊ mice starting at the age of 3 months. At the age of 6 months, enhanced proteoglycan degradation was observed in the articular cartilage of the knee and TMJs of the mutant mice. The expression of MMP-13 and DDR-2 protein and the amount of degraded type II collagen were higher in the knee joints of Col9a1 ؊/؊ mice than in their wild-type littermates at the age of 6 months. Changes in cartilage mechanics were observed in the femoral and tibial plateaus of Col9a1 ؊/؊ mice at 6 months, including a decrease in the compressive modulus and uniaxial modulus. At 3 and 6 months of age, tibial cartilage in Col9a1 ؊/؊ mice was found to be more permeable to fluid flow, with an associated compromise in the fluid pressurization mechanism of load support. All of these changes occurred only at medial sites.Conclusion. Lack of type IX collagen in Col9a1 ؊/؊ mice results in age-dependent OA-like changes in the knee joints and TMJs.

BackgroundsLung adenocarcinoma (LAC) accounts for the majority of lung cancer, which is the leading cause of cancer-related mortality worldwide. Keratin 17 (KRT17) was reported to promote the tumor development of skin tumor and oral cancer. The aim of this study was to investigate the expression and function of KRT17 in LAC.Material/MethodsImmunohistochemical staining and quantitative PCR were performed to explore the expression of KRT17 in both LAC tissues and adjacent normal liver tissues. Chi-square test, univariate analysis, and multivariate analysis were conducted to statistically evaluate the clinical significance of KRT17 in LAC. Proliferation, migration, and invasion capacities of LAC cells were assessed after overexpression or silencing KRT17.ResultsBoth the RNA and protein levels of KRT17 were up-regulated in LAC tissues compared to normal lung tissues. High expression of KRT17 was correlated with advanced TNM stage and poor overall survival. Moreover, KRT17 was identified as a novel independent prognostic factor for LAC patients. Cellular studies showed that KRT17 can enhance the proliferation, migration, and invasion capacities of LAC cells, thereby promoting tumor progression.ConclusionsHigh expression of KRT17 is frequent in LAC tissues, which promotes tumor proliferation and invasion, and is correlated with a poor overall survival. Targeting KRT17 may be a novel direction for LAC drug development.

Enterovirus A71 (EV-A71) is a major etiological agent of human hand, foot and mouth disease, and it can cause severe neurological complications. Although several genotypes of EV-A71 strains are prevalent in different regions of the world, the genotype C4 has circulated in mainland China for more than 20 years. The pathogenicity of different EV-A71 clinical isolates varies and needs to be explored. In this study, hSCARB2 knock-in mice (N = 181) with a wide range of ages were tested for their susceptibility to two EV-A71 strains with the subgenotypes C4 and C2, and two infection routes (intracranial and venous) were compared. The clinical manifestations and pathology and their relationship to the measured viral loads in different tissues were monitored. We observed that 3 weeks is a crucial age, as mice younger than 3-week-old that were infected became extremely ill. However, mice older than 3 weeks displayed diverse clinical symptoms. Significant differences were observed in the pathogenicity of the two strains with respect to clinical signs, disease incidence, survival rate, and body weight change. We concluded that hSCARB2 knock-in mice are a sensitive model for investigating the clinical outcomes resulting from infection by different EV-A71 strains. The intracranial infection model appears to be suitable for evaluating EV-A71 neurovirulence, whereas the venous infection model is appropriate for studying the pathogenicity of EV-A71.

ObjectivesPreventing stroke after coronary artery bypass grafting (CABG) remains a therapeutic goal, due in part to the lack of identifiable risk factors. The aim of this study, accordingly, was to identify risk factors in CABG patients with a previous history of stroke.MethodsPatients with a history of stroke who underwent CABG at Beijing An Zhen hospital from January 2007 to July 2010 were selected (n = 430), and divided into two groups according to the occurrence of postoperative stroke. Pre-operative and post-operative data were retrospectively collected and analyzed by univariate and multivariate logistic regression analyses.ResultsThirty-two patients (7.4%) suffered post-operative stroke. Univariate analysis identified several statistically significant risk factors in the post-operative stroke group, including pre-surgical left ventricular ejection fractions (LVEF) ≤50%, on-pump surgery, post-operative atrial fibrillation (AF), and hypotension. Multivariable analysis identified 4 independent risk factors for recurrent stroke: unstable angina (odds ratio (OR) = 2.95, 95% CI: 1.05-8.28), LVEF ≤50% (OR = 2.77, 95% CI: 1.23-6.27), AF (OR = 4.69, 95% CI: 1.89-11.63), and hypotension (OR = 2.55, 95% CI: 1.07-6.04).ConclusionUnstable angina, LVEF ≤50%, post-operative AF, and post-operative hypotension are independent risk factors of recurrent stroke in CABG patients with a previous history of stroke.