Tenascin-C fragments are endogenous inducers of cartilage matrix degradation

Cartilage destruction is a hallmark of osteoarthritis (OA) and is characterized by increased protease activity resulting in the degradation of critical extracellular matrix (ECM) proteins essential for maintaining cartilage integrity. Tenascin-C (TN-C) is an ECM glycoprotein, and its expression is upregulated in OA cartilage. We aimed to investigate the presence of TN-C fragments in arthritic cartilage and establish whether they promote cartilage degradation. Expression of TN-C and its fragments was evaluated in cartilage from subjects undergoing joint replacement surgery for OA and RA compared with normal subjects by western blotting. The localization of TN-C in arthritic cartilage was also established by immunohistochemistry. Recombinant TN-C fragments were then tested to evaluate which regions of TN-C are responsible for cartilage-degrading activity in an ex vivo cartilage explant assay measuring glycosaminoglycan (GAG) release, aggrecanase and matrix metalloproteinase (MMP) activity. We found that specific TN-C fragments are highly upregulated in arthritic cartilage. Recombinant TN-C fragments containing the same regions as those identified from OA cartilage mediate cartilage degradation by the induction of aggrecanase activity. TN-C fragments mapping to the EGF-L and FN type III domains 3-8 of TN-C had the highest levels of aggrecan-degrading ability that was not observed either with full-length TN-C or with other domains of TN-C. TN-C fragments represent a novel mechanism for cartilage degradation in arthritis and may present new therapeutic targets for the inhibition of cartilage degradation.     

Awareness, anxiety, compliance: community perceptions and response to the threat and reality of an influenza pandemic

This study compared community response prior to and during the H1N1 2009 influenza pandemic using a cross-sectional phone survey of rural and metropolitan South Australia, conducted in 2007 and 2009. Awareness of pandemic influenza was significantly higher and anxiety lower in 2009 than in 2007. Reported seasonal influenza vaccine uptake increased from 51.7% in 2007 to 61.4% in 2009, but there was more interest in receiving pandemic vaccine in 2007 (87.5%) than in 2009 (57%).     

Mineralocorticoid receptor blockade in chronic kidney disease

Mineralocorticoid receptor blockers (MRBs) have proven highly successful in the treatment of congestive heart failure and resistant hypertension. In contrast, their use in chronic kidney disease (CKD) has lagged due to the concern of hyperkalemia and, possibly, because of the incorrect assumption that traditional therapy with angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers consistently reduce aldosterone activity in all patients. Low-dose MRB therapy may offer additional antihypertensive and unique anti-inflammatory benefits in select CKD populations.     

Pegylated interferon for chronic hepatitis C in children affects growth and body composition: results from the pediatric study of hepatitis C (PEDS-C) trial

Weight loss and changes in growth are noted in children treated with interferon alpha (IFN-α). The aim of this study was to prospectively determine changes in weight, height, body mass index (BMI), and body composition during and after treatment of children with hepatitis C virus (HCV). Children treated with pegylated interferon alpha-2a (Peg-IFN-α2a) ± ribavirin in the Pediatric Study of Hepatitis C (PEDS-C) trial underwent anthropometric measurements, dual-energy X-ray absorptiometry scan, as well as dietary and activity assessments during and after treatment. One hundred and fourteen (55% male) children, with a mean age of 11 ± 3 years, were randomized, and 107 received treatment for at least 24 weeks. Subjects were divided into three groups according to duration of treatment: 24 (N = 14), 48 (N = 82), or 72 (N = 11) weeks. Decrements of up to 0.50 z score were observed for weight, height, and BMI while on therapy among all groups (P ≤ 0.01, compared to baseline). In the group treated for 48 weeks, 29 (33%) subjects had greater than 0.5-unit decrement in height-for-age z (HAZ) score. Though weight-for-age and BMI z scores returned to baseline after cessation of therapy, mean HAZ score was slower to rebound, still lower than baseline at 96 weeks post-therapy for the long-treatment duration group (P = 0.03) and lower than baseline in most children treated for 48 weeks. Percent body fat, fat-free mass z scores, and triceps skinfold z scores decreased with therapy. Dietary energy intake and levels of physical activity did not change during treatment. CONCLUSIONS: Peg-IFN-α2a was associated with significant changes in body weight, linear growth, BMI, and body composition in children. These effects were generally reversible with cessation of therapy, although HAZ scores had not returned to baseline after 2 years of observation in many. Longer term growth data are needed among children treated for chronic HCV.     

A human monoclonal antibody targeting scavenger receptor class B type I precludes hepatitis C virus infection and viral spread in vitro and in vivo

Endstage liver disease caused by chronic hepatitis C virus (HCV) infection is the leading indication for liver transplantation in the Western world. However, immediate reinfection of the grafted donor liver by circulating virus is inevitable and liver disease progresses much faster than the original disease. Standard antiviral therapy is not well tolerated and usually ineffective in liver transplant patients, whereas anti-HCV immunotherapy is hampered by the extreme genetic diversity of the virus and its ability to spread by way of cell-cell contacts. We generated a human monoclonal antibody against scavenger receptor class B type I (SR-BI), monoclonal antibody (mAb)16-71, which can efficiently prevent infection of Huh-7.5 hepatoma cells and primary hepatocytes by cell-culture-derived HCV (HCVcc). Using an Huh7.5 coculture system we demonstrated that mAb16-71 interferes with direct cell-to-cell transmission of HCV. Finally we evaluated the in vivo efficacy of mAb16-71 in "human liver urokinase-type plasminogen activator, severe combined immune deficiency (uPA-SCID) mice" (chimeric mice). A 2-week anti-SR-BI therapy that was initiated 1 day before viral inoculation completely protected all chimeric mice from infection with serum-derived HCV of different genotypes. Moreover, a 9-day postexposure therapy that was initiated 3 days after viral inoculation (when viremia was already observed in the animals) suppressed the rapid viral spread observed in untreated control animals. After cessation of anti-SR-BI-specific antibody therapy, a rise of the viral load was observed. CONCLUSION: Using in vitro cell culture and human liver-chimeric mouse models, we show that a human mAb targeting the HCV coreceptor SR-BI completely prevents infection and intrahepatic spread of multiple HCV genotypes. This strategy may be an efficacious way to prevent infection of allografts following liver transplantation in chronic HCV patients, and may even hold promise for the prevention of virus rebound during or following antiviral therapy.     

Should We Establish a New Protocol for the Treatment of Peripartum Myocardial Infarction?

Peripartum myocardial infarction is a rare event that is associated with high mortality rates. The differential diagnosis includes coronary artery dissection, coronary artery thrombosis, vascular spasm, and stenosis. Our evaluation of 2 cases over a 5-year time period has led to a hypothesis that peripartum myocardial infarction is an immune-mediated event secondary to coronary endothelial sensitization by fetal antigen. In our patients, we supplemented standard medical therapy with immunotherapy consisting of corticosteroids, plasmapheresis, and intravenous immunoglobulin. Herein, we present our most recent case-that of a 29-year-old black woman (gravida V, para IV), 2 weeks postpartum with no relevant medical history. She presented with a 1-week history of chest pain. Initial electrocardiographic and cardiac biomarkers were consistent with acute coronary syndrome. Echocardiography revealed reduced systolic function with inferior-wall hypokinesis. Angiography revealed diffuse disease with occlusion of the left anterior descending coronary artery not amenable to revascularization. We were successful in treating the myocardial infarction without the use of catheter-based interventions, by modifying the immunologic abnormalities. Two cases do not make a protocol. Yet we believe that this case and our earlier case lend credence to the hypothesis that peripartum myocardial infarction arises from sensitization by fetal antigens. This concept and the immune-modifying treatment protocol that we propose might also assist in understanding and treating other inflammatory-disease states such as peripartum cardiomyopathy and standard acute myocardial infarction. All of this warrants further investigation.     

Hypoplastic right-heart syndrome presenting as multiple miscarriages

Reversible causes of miscarriage are many, but they affect only 1% of women who are trying to conceive. Herein, we describe the case of a 23-year-old woman who presented for evaluation of repeated miscarriages and was found to have hypoxemia and erythrocytosis. Further evaluation revealed hypoplastic right-heart syndrome with an intracardiac shunt. She underwent hybrid repair with pulmonary valve balloon valvuloplasty, followed by surgery to perform atrial septal defect closure and a Glenn anastomosis. The erythrocytosis and hypoxemia resolved, and she was able to conceive and deliver a healthy baby at term 2 years later. This is a unique case of a rare congenital heart defect that went unnoticed until adulthood, when attempts at pregnancy failed because of the associated hypoxemia. Timely and appropriate treatment led to a successful pregnancy after repeated miscarriages. This case exemplifies the need for a comprehensive medical evaluation of every woman with a history of multiple miscarriages to determine whether a reversible cause exists.