Thrombin generates previously unidentified C5 products that support the terminal complement activation pathway

The coagulation and complement pathways simultaneously promote homeostasis in response to injury but cause tissue damage when unregulated. Mechanisms by which they cooperate are poorly understood. To delineate their interactions, we studied the effects of thrombin and C5 convertase on C5 in purified and plasma-based systems, measuring release of the anaphylatoxin C5a, and generation of C5b, the initial component of the lytic membrane attack complex. Thrombin cleaved C5 poorly at R751, yielding minimal C5a and C5b. However, thrombin efficiently cleaved C5 at a newly identified, highly conserved R947 site, generating previously undescribed intermediates C5(T) and C5b(T). Tissue factor-induced clotting of plasma led to proteolysis of C5 at a thrombin-sensitive site corresponding to R947 and not R751. Combined treatment of C5 with thrombin and C5 convertase yielded C5a and C5b(T), the latter forming a C5b(T)-9 membrane attack complex with significantly more lytic activity than with C5b-9. Our findings provide a new paradigm for complement activation, in which thrombin and C5 convertase are invariant partners, enhancing the terminal pathway via the generation of newly uncovered C5 intermediates. Delineating the molecular links between coagulation and complement will provide new therapeutic targets for diseases associated with excess fibrin deposition and complement activation.     

Left ventricular mass and function with reduced-fat or reduced-carbohydrate hypocaloric diets in overweight and obese subjects

In animals, carbohydrate and fat composition during dietary interventions influenced cardiac metabolism, structure, and function. Because reduced-carbohydrate and reduced-fat hypocaloric diets are commonly used in the treatment of obesity, we investigated whether these interventions differentially affect left ventricular mass, cardiac function, and blood pressure. We randomized 170 overweight and obese subjects (body mass index, 32.9±4.4; range, 26.5-45.4 kg/m(2)) to 6-month hypocaloric diets with either reduced carbohydrate intake or reduced fat intake. We obtained cardiac MRI and ambulatory blood pressure recordings over 24 hours before and after 6 months. Ninety subjects completing the intervention period had a full cardiac MRI data set. Subjects lost 7.3±4.0 kg (7.9±3.8%) with reduced-carbohydrate diet and 6.2±4.2 kg (6.7±4.4%) with reduced-fat diet (P<0.001 within each group; P=not significant between interventions). Caloric restriction led to similar significant decreases in left ventricular mass with low-carbohydrate diets (5.4±5.4 g) or low-fat diets (5.2±4.8 g; P<0.001 within each group; P=not significant between interventions). Systolic and diastolic left ventricular function did not change with either diet. The 24-hour systolic blood pressure decreased similarly with both interventions. Body weight change (β=0.33; P=0.02) and percentage of ingested n-3 polyunsaturated fatty acids (β=-0.27; P=0.03) predicted changes in left ventricular mass. In conclusion, weight loss induced by reduced-fat diets or reduced-carbohydrate diets similarly improved left ventricular mass in overweight and obese subjects over a 6-month period. However, n-3 polyunsaturated fatty acid ingestion may have an independent beneficial effect on left ventricular mass.     

The endocrine role of the skeleton: background and clinical evidence

Based on the observation that diabetes, obesity, and hypogonadism influence bone metabolism, the existence of a feedback loop and a common regulation was postulated and an endocrine role ascribed to the skeleton. In the first part of this review, two pathways are described whereby adipose tissue acts on bone mass. In the first, leptin activates the sympathetic nervous system via serotonin and diminishes bone mass accrual. The second pathway functions via the activation of CART (CARTPT) and inhibits bone resorption. The first pathway leads to a decrease in bioactivity of the osteoblast-produced hormone osteocalcin (OC) (part 2). In its undercarboxylated form, OC acts on the three targets pancreas, adipose tissue, and gonads (part 3) and thereby causes an increase in insulin secretion and sensitivity, β-cell proliferation, and male fertility. Insulin (part 4) is part of a recently discovered regulatory feedback loop between pancreas and osteoblasts. It is a strong counterplayer of leptin as it causes a decrease in OPG expression and enhances bone resorption and OC decarboxylation. Numerous clinical studies (part 5) have shown associations of total and undercarboxylated OC and markers of energy metabolism. Interventional studies, to date only performed in murine models, have shown positive effects of OC administration on energy metabolism. Whether bone tissue has an even further-reaching endocrine role remains to be elucidated.     

Unsustainable funding of high‐burden tuberculosis control programmes: who is responsible?

The literature suggests that crowding‐out effects of government funding for health happen in low‐income countries with a high HIV burden. In a survey, we investigated the hypothesis that domestic funding for TB control has fallen in 11 low‐income, high‐TB‐burden countries in the context of changes in gross domestic product (GDP), development assistance inflows and national health expenditures. We found that despite rises in GDP per capita between 2003 and 2009, health expenditure as per cent of GDP fell or stayed the same for the majority of these countries. Although TB control budgets increased for all 11 countries in absolute terms, 6 countries reduced government contribution to TB control. For health programmes to become sustainable in the long run, we suggest increases in donor funding for health to be accompanied by requirements to increase domestic funding for health. We thereby attribute responsibility to avoid crowding‐out effects to donors and governments alike. Moreover, it is the responsibility of both to ensure essential items to be funded by government sources to avoid a collapse of programmes once aid is withdrawn.     

Histone deacetylase inhibitors as potential therapeutic approaches for chordoma: An immunohistochemical and functional analysis

Chordomas are rare malignancies of the axial skeleton. Therapy is mainly restricted to surgery. This study investigates histone deacetylase (HDAC) inhibitors as potential therapeutics for chordomas. Immunohistochemistry (IHC) was performed using the HDAC 1–6 antibodies on 50 chordoma samples (34 primary tumors, 16 recurrences) from 44 patients (27 male, 17 female). Pan‐HDAC‐inhibitors Vorinostat (SAHA), Panobinostat (LBH‐589), and Belinostat (PXD101) were tested for their efficacy in the chordoma cell line MUG‐Chor1 via Western blot, cell cycle analysis, caspase 3/7 activity (MUG‐Chor1, UCh‐1), cleaved caspase‐3, and PARP cleavage. p‐Values below 0.05 were considered significant. IHC was negative for HDAC1, positive for HDAC2 in most (n = 36; 72%), and for HDACs 3–6 in all specimens available (n = 43; 86%). HDAC6 expression was strongest. SAHA and LBH‐589, but not PXD101 caused a significant increase of G2/M phase cells and of cleaved caspase‐3 (p = 0.0003, and p = 0.0014 after 72 h, respectively), and a peak of caspase 3/7 activity. PARP cleavage confirmed apoptosis. The presented chordoma series expressed HDACs 2–6 with strongest expression of HDAC6. SAHA and LBH‐589 significantly increased apoptosis and changed cell cycle distribution in vitro. HDAC‐inhibitors should be further evaluated as therapeutic options for chordoma. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1999–2005, 2013     

Trauma Exposure and Posttraumatic Stress Disorder in Adolescents: A National Survey in Switzerland

There are a limited number of epidemiological studies that have focused on trauma exposure and prevalence of posttraumatic stress disorder (PTSD) in representative general population samples of adolescents, especially outside of the United States. We therefore aimed to assess the lifetime prevalence of traumatic events (TEs) and current prevalence of PTSD, and to examine demographic risk factors for TEs and PTSD in a representative sample of adolescents. Data were collected by a school survey among a sample of 6,787 9th‐grade students in Switzerland. Roughly 56% of the adolescents (females 56.6%; males 55.7%) reported having experienced at least 1 TE. Non‐Swiss nationality (OR = 1.80), not living with both biological parents (OR = 1.64), and lower parental education (OR = 1.18) were associated with a higher risk of trauma exposure. The current prevalence of PTSD according to the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM‐IV‐TR; American Psychiatric Association, 2000) criteria was 4.2% (females 6.2%; males 2.4%). Female gender (OR = 2.70), not living with both biological parents (OR = 1.47), lower parental education (OR = 1.51), and exposure to multiple TEs (OR = 9.56) were significant risk factors for PTSD. Results suggest considerably high rates of TEs and PTSD among adolescents. Intervention efforts must be intensified to reduce trauma exposure and treat PTSD.     

The predictive potential of the sweat chloride test in cystic fibrosis patients with the G551D mutation

BackgroundIvacaftor, a cystic fibrosis transmembrane regulator (CFTR) potentiator, decreased sweat chloride concentrations and improved clinical measures in cystic fibrosis (CF) patients with the G551D mutation.ResultsSweat chloride measurements at day 15 had an overall positive predictive value (PPV) of 86.3%, a negative predictive value (NPV) of 65.5%, sensitivity of 73.9%, and specificity of 80.9% for an FEV₁ improvement of ≥ 5% from baseline at week 16. For ivacaftor patients the median FEV₁ improvement was 16.7%; for placebo patients 0.4%. For patients aged 6–11 years who received ivacaftor and who had a sweat chloride decrease of ≥ 40 mmol/L from baseline at day 15, a median weight gain of 11.2% at week 16, compared to 6% for those with a smaller decrease was observed.ConclusionsChanges in sweat chloride concentration at day 15 following treatment with ivacaftor may have sufficient predictive potential to identify individuals that show improvement in pulmonary function and weight gain after 16 weeks of treatment.     

Peripheral neuropathy as initial manifestation of primary systemic vasculitides

Peripheral neuropathies are well-known complications of primary systemic vasculitides. In rare cases, peripheral neuropathies are among the first symptoms of these diseases. In this prospective study, 89 consecutive adult patients with newly diagnosed primary systemic vasculitis were screened, of whom 22 patients (25 %, 12 men, ten women, mean age, 59 years, range, 26–82 years) suffered from peripheral neuropathy due to systemic vasculitis at initial presentation. Peripheral neuropathy was most frequent in newly diagnosed patients with eosinophilic granulomatosis with polyangiitis (Churg–Strauss syndrome, 12 out of 20 patients, 60 %) and polyarteritis nodosa (three out of six patients, 50 %), and less common in patients with granulomatosis with polyangiitis (six out of 47 patients, 13 %) and microscopic polyangiitis (one out of 16 patients, 6 %). Multiplex mononeuropathy was more frequent (n = 13, 59 %) than symmetric polyneuropathy (n = 9, 41 %). The nerves commonly affected were the peroneal nerve, followed by the sural, posterior tibial, and median nerves. Treatment options were chosen according to current guidelines of the national neurological and rheumatologic societies, with initial corticosteroid monotherapy for patients with a mild disease form and a combination of corticosteroids and intravenously pulsed cyclophosphamide for patients with a more extended organ involvement. During follow-up (mean, 34 months, range, 12–112 months), new neurological complications were rare (9 %): One patient suffered from a cerebral infarct while another patient sustained epileptic seizures. Two patients (9 %) died from sepsis (after 60 months) or severe gastrointestinal bleeding (after 13 months). The degree of neurological disability measured by the functional disability score (described by Prineas) improved in 20 of 22 patients after 12 months of therapy.